Taking a Look at Affirmative Action - 2016 Words

Introduction of Issue Affirmative action is a product of the 1960’s Civil Rights Movement and it is intended to provide equal opportunities for those who have been historically discriminated against within our society. Affirmative action policies are those that make an effort to improve opportunities for historically excluded groups within our society. When focusing on higher education, affirmative action is often referring to admission policies that have been put in place to provide equal access to education for groups that have been historically discriminated against, such as minority groups. This topic is greatly debated across college campuses within the United States. Supporters of affirmative action argue that after California Colleges in 1998 had dropped their affirmative action programs, that minority admissions had reportedly fallen. For example UC Berkeley’s admissions fell 61%, and UCLA 36% (Messerli, 2014). Critics of affirmative action argue that the policy is outdated, that we no longer live in a highly racial society, and that this policy is now causing reverse discrimination by favoring one group over another affirmative action is currently an issue not because there is extensive public outcry in support of racial discrimination, this is not to say that racial discrimination does not persist. The controversy of this issue surrounds around the disagreement about how to best fight discrimination in the current day, and whether to even recognize ifShow MoreRelated Problems with Affirmative Action Essay737 Words   |  3 Pages Affirmative Action   Ã‚  Ã‚  Ã‚  Ã‚  For many years, people have presumed that Affirmative Action has played and continues to play a vital and important role in the lives of most minorities . However, some people have raised questions about the effectiveness of Affirmative Action. Since its conception, it has been believed that in some instances, Affirmative Action has been more harmful then helpful. One may ask the question, is Affirmative Action really worth fighting for? Some may argue, that if it had notRead More Affirmative Action Essay1086 Words   |  5 Pages The roots of Affirmative Action can be traced back to the passage of the Civil Rights Act where legislation redefined public and private behavior. The act states that to discriminate in private is legal, but anything regarding business or public discrimination is illegal. There are two instances when opposing affirmative action might seem the wrong thing to do. The nobility of the cause that help others. Affirmative Action was a great starter for equality in the work place. The mostRead MoreSummary : Rough Draft And Affirmative Action Program1575 Words   |  7 PagesJarron Jones 4-11-15 Moral Problems Rough Draft Affirmative Action In 2003, the Supreme Court issued its ruling on a case challenging the University of Michigan’s undergraduate affirmative action program, ultimately declaring the scheme unconstitutional. The admission scheme was based generally on a 150 point scale system in which the Office of Admission assigned points based on a number of factors, including high school grades, standardized test scores, high school quality, alumni strength, andRead More Affirmative Action Essay561 Words   |  3 Pages The purpose of affirmative action is to ensure equal opportunity for minorities. But it has strayed from its original intent and has become largely a program to achieve not equal opportunity but equal results. It is a system of quotas forced upon American businesses and working class by the federal government. A law which forces people to look at race before looking at the individual cannot promote equal opportunity. Affirmative action continues the judgement of minorities by race; it causes reverseRead MoreAffirmative Actions1078 Words   |  5 PagesRunning Head: AFFERMATIVE ACTION Affirmative Actions Affirmative action is an action taken by an organization to select on the basis of race, gender, or ethnicity by giving due preferences to minorities like women and races being not adequately represented under the existing employment. To make the presentation of all these compositions almost equal in proportion to do away the injustice done in the past. The Supreme Company need to design an affirmative action program in the light ofRead MoreThe Precedency: Supporting the Affrimative Action Essay1486 Words   |  6 PagesAffirmative action is a government policy that gives opportunities to minorities, women, and any group who has been the victim of discrimination in the past. Affirmative action is the outcome of the 1960’s Civil Rights movement, growing out of the Civil Rights Act of 1964 which outlawed discrimination based on race, ethnicity, or gender. It was the 1978 Supreme Court decision, The Regents of the University of California v. Bakke, which allowed for the use of race-based preferences as a means ofRead MoreAffermative Action1316 Words   |  6 PagesBy: Elissa Thomas E-mail: elissa@usais.net Affirmative Action Affirmative Action efforts were started in 1964 to end the long history of overlooking qualified people of color and women from higher education. Affirmative Action sets standards for a business or office of admissions, so that a white man does not have the upper-hand over an equally or greater educated minority. The initial way the government tried to justify Affirmative Action was to develop a human resource approach: first identifyingRead MoreAffirmative Action: Social Policy1348 Words   |  6 PagesAffirmative Action Affirmative action is a social policy created to promote the welfare of minorities by supporting the idea that individuals are all created equal and should not be judged by race or gender. Therefore, in situations like job and university applications, we should consider minorities to be as feasible a choice for hire as a white male candidate, taking into consideration their background. In short, it tries to give minorities that have been at a disadvantage their whole life, anRead MoreDoes Affirmative Action Make Moral Sense?1084 Words   |  5 PagesDoes affirmative action make moral sense? A moral being is one capable of conforming to the rules of right conduct, but a big question that follows concerns the idea if there even is such a thing as â€Å"right conduct.† â€Å"Whatever can be proved to be good, must be so by being shown to be a means to something admitted to be good† (Mill 6). In John Stuart Mill’s book, â€Å"Utilitarianism,† he states this notion where an individual assumes good things are good without knowing why they’re good. Defined fromRead MoreDifferences Between Equal Employment Opportunity Initiatives, Affirmative Action Initiatives and Diversity Initiatives in Organizations1120 Words   |  5 Pages(Wisconsin Work Force Planning) Differences between Equal Employment Opportunity initiatives, Affirmative Action initiatives and Diversity initiatives in organizations Tim Piper Issues in Human Resources Management – MBA 910 February 14, 2012 To best understand how affirmative action (AA), equal employment opportunity (EEO) and diversity work together, I will take a look at each of them and how they interact with each other and also explore the differences of the three initiatives . First

Free Will and Fate Things Fall Apart - 844 Words

Fate and Free Will The idea about free will and fate is still unsolved and debatable throughout the world. Some claim that humans have their own power to create their own destiny, however, others argue that they are inescapable victims of fate. The novel, Things Fall Apart, portrays the relationship between human’s determination to succeed and his or her own fate by describing Okonkwo as a tragic figure. While Okonkwo believes that he can overcome his fate through his hard work, Chinua Achebe reveals that fate is a powerful, inevitable event in the novel. In the beginning of Things Fall Apart, Okonkwo is highly praised all over Umuofia for his great wealth and power. Achebe praises the achievements of the protagonist as he†¦show more content†¦Fearing that these changes might result his downfall in his social status and destruction of his family, he abhors Christianity. Through this misfortunes, Okonkwo starts to realizes that destiny is more powerful than himself as he mentions, â€Å"A man could not rise beyond the destiny of his chi. The saying of the elders was not true – that if a man said yeah his chi also affirmed. Here was a man whose chi said nay despite his own affirmation.† (131) Even though Okonkwo does some violent and cruel things, such as beating his wife and killing Ikemefuna, these are what he has to do to pursue what he believes for and obey the gods. These deeds are not that immoral and sinful to bring great calamities to his life. This demonstrates that fate is more powerful than humansâ₠¬â„¢ acts and beliefs. As a result, Okonkwo, is a man who thinks that he can overcome the destiny, however, he begins to laments for his misfortunes and slowly accept the existent power of fate that dominates his life. Still unable to accept and adapt to the change he encounters, Okonkwo uses a method of violence by killing the messenger from the Christians and at last kills himself. Okonkwo’s suicide marks that he finally meets his fate. He stands for his power, strength, and masculinity and has great pride for his achievement. After realizing that he cannot conquer his chi and escape from miserable events, he gives up his life byShow MoreRelated Fate and Free Will in Chinua Achebes Things Fall Apart Essay1232 Words   |  5 PagesFate and Free Will in Chinua Achebes Things Fall Apart   Ã‚  Ã‚   The tragic story of Okonkwo in Chinua Achebes Things Fall Apart offers many examples of Igbo beliefs regarding free will and fate. Religious life for the Igbo was thoroughly intertwined with secular life. According to the text, the Igbo believed in fate; that nothing happened by chance as every happenstance was the result of Chukwu or Gods will. Yet the Igbo also believed that ancestors, lesser gods, and their own chi or personalRead MoreThe Book Things Fall Apart Is One Of Africa’S Most Significant1601 Words   |  7 PagesThe book Things Fall Apart is one of Africa’s most significant works of literature. Because of its unique spin on European colonialism from an African tribesman’s perspective and its eloquent use of Igbo vocabulary, the volume continually draws in readers from various backgrounds and locations. Attention to detail and foreshadowing are common throughout the book; zeroing in on certain motifs and themes relating to African c ulture. One motif examined throughout the novel is chi. Author Chinua AchebeRead MoreExamples Of Free Will In Macbeth1015 Words   |  5 PagesIs one’s life dominated by fate or free will? Perhaps one’s future has been predetermined by some external force or perhaps one has the choice to pave their future. These ideas are further explored in the the novel Things Fall Apart by Chinua Achebe and the play Macbeth by Shakespeare. Things Fall Apart is about a man named Okonkwo’s struggle between the changes that arise with the arrival of white missionaries in the villages of his home in Nigeria, the conflicts that arise between the arrival ofRead MoreFahrenheit 451 Comparison Essay1698 Words   |  7 Pageswant to be on--what they want to be remembered for. Whether that’s fighting for transgender rights as can be seen in the 21st century, or fighting to be considered a free man as can be seen in the 19th century. This fight can be seen throughout history boo ks and literary classics such as Fahrenheit 451 by Ray Bradbury and Things Fall Apart by Chinua Achebe. In Fahrenheit 451, the main character, Guy Montag is fighting against the technological revolution taking place in the 23rd century. He battles withRead MoreThings Fall Apart : A Great African Tragedy1727 Words   |  7 PagesPeter Thomas Mid-Term Paper English 3510 10-12-17 Things Fall Apart: A Great African Tragedy Tragedy is not new to Africa, precolonial, colonial, or postcolonial. Despite this, the continent of Africa and the countries within are not known for tragic literature. If any single work can make African literature, especially African tragedy stand out, Things Fall Apart can. Things Fall Apart fits the genre of tragedy due to Okonkwo’s role as a tragic character. He exhibits all of the traits of the tragicRead More Moving as a Child Essays999 Words   |  4 PagesMoving as a Child Some things in life are just meant to happen. Fate brought me to the seat I am sitting at, in this university, miles and miles from where I was born. I never thought I would move. The idea was inconceivable for an eight-year-old girl. Life was an endless cycle of days spent chasing butterflies, catching ladybugs, and blowing apart dandelions while nights were full of stars, crickets, and peace. I have learned since that moment that fate has a different idea in mind,Read MoreThe Death Of A Salesman And Oedipus The King797 Words   |  4 Pageshis questionable and mysterious death, to Oedipus dynamic and complex choices and kingly personality that determines his fate. A tragic hero is a literary character who makes a judgement that leads to his/her downfall. In other words, even though both characters made incredible contributions and left a very noble legacy, their choices and decisions determined their ultimate fate. In today’s world tragic heroes are commonly prese nt, with the increasingly bad error that causes hamartia. Therefore, bothRead MoreOedipus, an Ironic Tragic Hero1034 Words   |  5 PagesTragic Hero Much of the tragedy of the play comes from the irony involved in fate Oedipus’s life. Being a tragic hero Oedipus is on a quest for truth, during his quest he realizes that if he continues on his quest for truth he will cause himself great harm yet he continues his pursuit for truth. The audience is seized by the ironic nature of this play, and the tragic nature of Oedipus’s life. Oedipus is lines up against fate and takes steps to try not to fulfill the prophecy that he will kill his fatherRead MoreThings Fall Apart By Chinua Achebe1204 Words   |  5 Pagesroles in determining a person’s life in Umuofia society. Sometimes a man with sheer force of will cannot change his future through hard work. One of the main conflicts in Things Fall Apart by Chinua Achebe is the clash between Okonkwo’s determination to succeed, his free will, and fate – which seems to have less appealing things in mind. Okonkwo’s will plays a major factor in determinin g his future; he chooses to kill Ikemefuna with his own hands, he chooses to kill a government official, and in theRead MoreLiterary Analysis Of Things Fall Apart Themes1246 Words   |  5 PagesLiterary Analysis of Things Fall Apart Themes Masculinity â€Å"Okonkwo ruled his household with a heavy hand. His wives, especially the youngest, lived in perpetual fear of his fiery temper† (Achebe 13). Okonkwo is the definition of hypermasculinity. As someone who condemns all things feminine, he never learned how to express his feelings, leading to him lashing out in violence instead. It is important to note his treatment of the women in his life as well. Okonkwo’s poor, often times abusive relationship

IRA Peace Settlement Essay Example For Students

IRA Peace Settlement Essay The Irish Republican Army, also known as the IRA, is a parliamentary and nationalist organization that opposes the connection of Northern Ireland to Great Britain. The IRA is also dedicated to the creation of a single unified Irish state. The name IRA derived from the veterans of the Easter Battles of 1916. The battle was fought for support of Irish independence. Accordingly the IRA became the political division of the Sinn Fein party. The political leaders of Britain and Ireland, negotiated a treaty that incorporated 26 of Ireland’s counties as the Irish Free State. The remainder of Ireland, remained part of the United Kingdom. The Irish Republican Army began to decline after Eamon de Valera became a prime minister and took over the Irish government. The IRA and the Irish state were in constant conflict, during the 1930s and 1940s. The IRA started to concentrate on Northern Ireland in the 1950s. The IRA tried to gain favor from Northern Ireland, but failed. In 1969 the IRA started new radical social reforms in Northern Ireland, and the British government couldn’t overcome them after a dozen years.This crisis also allowed the IRA to make a drastic comeback. The Irish Republican Army was split into two groups.The officials, which promoted a Socialist Ireland by democratic means, and provisionals, that promoted terrorism.In 1972 the Provisional IRA’s terrorist tactics led to the downfall of the Northern Ireland government. From 1972 to 1994 the Provisional IRA maintained their campaign on terminating British victims in Northern Ireland and Britain. On August 31, 1994, the Irish Republican Army announced a cease-fire. This would affect the 25-year-old battle against British domination of Northern Ireland. This cease-fire came about from several years of confidential meetings between the IRA and the British government. This arrangement for peace is called the â€Å"Downing Street Declaration.†The controversy between Northern Ireland and Britain began with Roman Catholic objections against favoritism by the protestant majority in the country. British troops were sent into Northern Ireland to patrol the country. They still remained there in 1994. The Catholic minority wanted a reunion with the Republic of Ireland, which was mainly Catholic. The Protestants of Northern Ireland resisted the reunification. The IRA gave no amount of time for the duration of the cease fire, nor did they surrender their weapons. There were two earlier cease-fires in 1972 and 1975, but they failed to last. Nationalists, supporters of the Irish Republican Army and others have grown tired of the Northern Ireland conflict, and celebrated the announcement of the cease-fire. The IRA has commanded its units to obey a complete halt of military actions. In the first public meeting between Gerry Adams (the leader of Sinn Fein), Albert Reynolds (the Irish Republic’s prime minister), and John Hume (the leader of Northern Ireland’s Catholic nationalist), the British government was not pleased with the stating of the cease-fire. The British government was warily optimistic about the conference. A political scandal led to the collapse of the Irish government in Dublin. Throughout the years, Dublin acted as a halfway house between the Irish, British and American governments. The prime minister Albert Reynolds was replaced by John Bruton. A terrorist, loyalist and Protestant militia called the Ulster Defense Association shot and killed a Catholic man. The loyalists work with the sympathetic Protestant officers in the Royal Ulster Constabulary.This proved that the IRA was not the only forceful group in the Northern Ireland crisis. The Protestant militia soon after the killing called a cease-fire. This group was responsible for more deaths than the IRA, in the two years before the cease-fire was called. Ian Paisley, a leader of the Ulster Unionist Party, protested that the IRA must surrender their arms before any contact between the IRA and the British government can proceed. Paisley also continued to disapprove the idea of representatives of Sinn Fein to take part in all the meetings dealing with the future of Northern Ireland. Minds Are Open Only When Hearts Are Open Argumentative EssayThe political leaders of Britain and Ireland agreed to a peace agreement that would end violence. It gave the Catholic minority more privileges in the north, and it confirmed that the Protestants would not be dominated by the Catholic south. It addressed the largest reform in Ireland’s political structures since it was split in 1921. The result of the arrangement took place on June 25, 1998. This also created a Northern Ireland Assembly, a council for the North and the South. The people of Ireland voted in support of the Good Friday peace agreements, that assured adjustment in the way Northern Ireland will be governed. Majority of both Northern Ireland and the Irish Republic voted yes. To test the peace agreement the â€Å"Real IRA† planted a bomb, which killed 29 peoples and injured hundreds. The â€Å"Real IRA† apologized for the attack and announced a truce of its own. More killings continued within the Protestant and Catholic communities, and this raised the concern that the violence would continue despite the peace process. The Northern Ireland Assembly in 1998 reached an accord for an all-party cabinet. This gave way for the new system of government. The plan was put forth by David Trimble, the Ulster Unionist leader, and his deputy from the Catholic Social Democratic and Labor Party, Seamus Mallon. The plan was approved by a vote, but it was almost ruined by Protestant deputies who wanted the IRA to start decommissioning its large weapon stashes before the Assembly undertook power. On April 1, 1999, Tony Blair, British Prime Minister, and Bertie Ahern, Irish Prime Minister, predicted they would find a solution to the Protestant-Catholic Administration for Northern Ireland. Ahern and Blair tried to convince the other parties to agree on a â€Å"national day of reconciliation.†This would start the means of disarmament for the IRA and other British gangs. David Trimble would not get his party to support Sinn Fein until they would disarm. Mitchel McLaughlin, Sinn Fein chairman, claimed that the agreement does not require the IRA to disarm. McLaughlin also stated that negotiations on disarmament could be brought about if Sinn Fein politicians could have power in the new government. After four nights of negotiations at the all-party peace talks in Belfast no solution was found, and Tony Blair called for a break. The Anglo-Irish summit was reconvened on April 14, 1999. The political leaders of Irish and British governments tried to break the deadlock over the issue of disarmament. There was no proof that pointed to an early progress between Sinn Fein and the Ulster Unionists conflict. The issue of disarmament was the biggest conflict since the Good Friday agreement. At Belfast on May 3, 1999, the Irish and British governments, led by Tony Blair and Bertie Ahern, again tried to negotiate a new plan to end the stalemate. The plan would organization a transitional executive made up of ministers from all parties, and it would have six-month limit for settlement on the issue of disarmament. The proposal also stated that the Sinn Fein party would have until May 2000 to disarm, and all arms have to be shed before entering the executive. Though the cease-fires are maintaining, there are occasional cases of violence from the rivals of the Good Friday agreement. Also on May 3, 1999, Bertie Ahern denied information that the Irish and the British were contemplating on a plan to form a new executive. The IRA has dismissed the pleas to disarm by comparing disarmament to degrading surrender. Years of negotiating and devising new plans to solve the Northern Ireland crisis has failed to be solved. After solving the problem of the cease-fire, the problem of disarmament still consists. Tony Blair and Bertie Ahern have not yet found a solution for the issue of disarmament. The Irish Republican Army believes disarmament to be surrender and the Ulster Unionists believes disarmament to be a scare tactic. Therefore, giving each other no choice but to disagree and stagnate.

IRA Is Force Justified Essays - Irish Republicanism,

IRA : Is Force Justified? The Irish Republican Army is not justified in using force to achieve its aims because the Irish Republican Army (IRA) represents the minority of the population in Northern Ireland. The IRA also is not justified in using force because using force does not work and it turns their supporters against them. The IRA's goals are political and political rights should be achieved through political methods, not by force. In cases where the majority of the population is not fairly represented in the government and peaceful protests and demonstrations have not been successful, then resorting to armed resistance is justified. For example, in the case of the American Revolution, the colonists' armed resistance was justified because they represented the majority, and they had already tried to gain independence peacefully through protests and demonstrations and they probably would have never have gained their independence otherwise. Another example when armed resistance is justified is in South Africa, where the Black majority has been trying for years to gain equal rights. In the case of the IRA, even though it has tried to gain independence from Great Britain through demonstrations and protests, it does not represent the majority of people in Northern Ireland. Therefore, the IRA is not justified in using force to achieve it's aims. In order to understand the IRA, one has to understand the history of Ireland. In 1641 a ten-year rebellion began in Ireland to gain it's independence from England. England had been occupying Ireland for centuries. The rebellion cost 60,000 Irish lives. For the next 150 years, Protestants dominated Ireland. In 1801 the Act of Union joined Ireland with Great Britain, forming the United Kingdom. In 1829 the English Parliament passed an act giving the Catholics in Ireland political equality for most purposes. Later, Ireland set forth to eliminate the Act of Union. The Catholics in Southern Ireland wanted Home Rule, but the Protestants in Northern Ireland wanted to keep the Act of Union with Great Britain. On Easter Monday, 1916, Irish volunteers armed themselves and united with the Citizen army and staged an unsuccessful rebellion in Dublin, a town in Northern Ireland. The leaders of the rebellion were executed by the English, which made the Irish nationalists mad at England. In 1918 el ections took place electing members of Sein Fein, the Irish revolutionary party, into the seats of the English Parliament. Instead of taking their seats, they set up a new Parliament in Ireland, and proclaimed Ireland's independence from Great Britain. The Irish Republican Army (IRA) was developed when the Irish volunteers tried to defend themselves from the British, who tried to put down the new Parliament. In 1921 a truce was signed between Great Britain and the IRA called the Anglo-Irish treaty. It gave Home Rule to Southern Ireland, which was later called the Irish Free State. Northern Protestant Ireland was left a colony of Great Britain because that is what the majority of the people in Northern Ireland wanted. The Irish Catholics of Southern Ireland voted their approval of the treaty. Some Catholics remained in Northern Ireland when the border was made to separate the North and the South. The Catholics in Northern Ireland continued to want unity with Southern Ireland and inde pendence from Great Britain, so the IRA remained intact fighting for independence. The Catholics do have many reasons to want political unity and equal rights in Northern Ireland. In the past in Northern Ireland, the Catholics were convicted of crimes without being tried, and their religion determined their housing and their jobs, which for the Catholics, usually meant they lived in the ghettos and had the ?left-over? jobs. ?(Catholic) housing was poor. They suffered from the usual forms of anti-Catholic discrimination. Their economic prospects were bleak.? As recently as 1985 unemployment in Northern Ireland was 21.8 percent compared to 17.2 percent in the South. The IRA does have reasons to be mad at the Protestants of Northern Ireland, but terrorism will not solve their problems. Terrorism will only bring them farther from their aims, and terrorism is never justified as a means to solve problems. Great Britain has been trying for several years to appease the people of Ireland and to gain peace.

Role of Technology in Retail Sector

Role of Technology in Retail Sector Today, in the 21st century, retailers all over the world are increasingly obtaining profit in return by delivering customer satisfaction through the adoption of many powerful technologies.Advertising We will write a custom assessment sample on Role of Technology in Retail Sector specifically for you for only $16.05 $11/page Learn More Indeed, technology has substantially shifted the landscape of the retail industry, as more retailers adopt and implement technological solutions that accentuate mobility, efficiency, competitiveness and sustainability (Delgado 2012; Fiorito et al 2010). The present paper attempts to discuss how technology is utilized in the retail sector, how it has impacted the retail business and its customers, and the critical technologies found in the retail industry. Technology is utilized in the retail sector in numerous ways not only to achieve profitability and competitiveness for the organization, but also to generate value for custome rs and change the relationship with customers and other trading agencies (Ko Kincade, 1997). Novel technologies such as Point-of-Sale (POS) systems can be utilized in the retail sector for efficient and effective transactions, proper accounting, â€Å"customer loyalty, CRM [Customer Relationship Management], PCI [Payment Card Industry] issues, back office transfers and receiving, time-keeping and scheduling, and task management†(Delgado, 2010 p. 10). Other technological solutions, such as the Retail Pro system and Microsoft Retail Management System, have been effectively used in retail to, among other things: minimize theft and human error; enhance efficiency and speed in the checkout process; provide extensive tracking of business transactions, discounts and products; avail up-to-date sales productivity statistics; facilitate inventory control and management; undertake purchase order management; and promote customer relationship management as well as payment processing solu tions (Delgado, 2010) Furthermore, some technological solutions such as e-business can be utilized to integrate emerging communication technologies with business processes and management practices via the internet, resulting in overall transformation of the relationships that retailers have with their customers, suppliers and other business partners (Bordonaba-Juste et al., 2012). In discussing the impact of technology on retail business and its customers, extant literature demonstrates that â€Å"web technologies help firms to understand customer needs, to customize products, to adopt product-market solutions, and to take customers’ orders† (Bordonaba-Juste et al., 2012 p. 533).Advertising Looking for assessment on business economics? Let's see if we can help you! Get your first paper with 15% OFF Learn More Retail businesses, in particular, are impacted by newer disruptive innovations such as e-business as they have to reorganize and restruct ure themselves continuously, with the view to integrating the technological solutions into their existing work processes to achieve profitability and competitiveness. Additionally, mobile payment programs have positively impacted the retail sector in terms of faster checkout times and the capacity by customers to receive e-mail receipts that are more convenient since they can be stored on a smart phone and accessed more easily than paper-based receipts (Delgado, 2010). Moving on, it is a well known fact that critical technologies in the retail sector have the capacity to tie a customer to a transaction, and consequently to a broad range of products, not only leading to the opening up of a new frontier for one-on-one marketing (Delgado, 2010), but also substantially changing the way business is conducted through availing important data both within the organization and to suppliers, channel partners and customers (Bordonaba-Juste et al., 2012). Such capabilities have been known to sig nificantly reduce customers’ search-related costs, facilitate the speed of reaction to important market information, provide a better shopping experience, decrease stock-out rate, improve inventory and replenishment rates, assist retailers to predict what is likely to occur and decide what to do next, and enhance access to new products in new channels, hence positively affecting the retailer’s bottom-line in terms of profits and competitive advantage (Fiorito et al., 2010; Ko Kincade, 1997; Puleri, 2011). However, a major negative impact of technology on retailers concerns the fact that â€Å"competitors are more numerous because the marketplace has no barriers and new entrants have access to a global market† (Bordonaba-Juste et al., 2012 p. 534). Another negative impact concerns the fact that some web-based technologies such as e-business avail critical market information not only to customers but also to competitors, implying that retailers must employ strate gies to ensure such information becomes a core competency rather than a disadvantage to the company (Barlow et al., 2004). In discussing the last section of the paper, which concerns the critical technologies found in the retail industry, it can be argued that quick response technologies such as electronic data interchange (EDI), bar-coding, and point-of-sale (POS) data capture act to improve inventory and replenishment rates, optimize the flow of information and merchandise between channel partners to optimize customer value and satisfaction, and improve turn of goods (Ko Kincade, 1997).Advertising We will write a custom assessment sample on Role of Technology in Retail Sector specifically for you for only $16.05 $11/page Learn More It is important to note the POS software solutions presently utilized in the retailing sector comprise â€Å" Retail Pro, Microsoft Retail Management System (RMS), and Keystroke POS, while examples of leading POS hardware sys tems are HP’s rp5800 Point of Sale solution, IBM’s SurePOS 500 system, and NCR’s RealPOS 25 system† (Delgado, 2010 p. 11). Other technologies currently used in the retail sector include smart phones, iPods, iPads, tablets, Quick Response (QR) codes, and Radio Frequency Identification (RFID). Individually and collectively, these technologies are known to enhance mobility, efficiency and customer satisfaction, while also providing valuable product information and facilitating the capacity for the retailer to know how much inventory of any particular product they have, right down to size, quantity and color (Barlow et al., 2004; Delgado, 2010). Overall, it can be concluded that the adoption of emerging technologies is the right way to go for retailers in their attempt to revolutionalize the sector in not only achieving profitability and competitive advantage for the businesses, but also in enhancing customers’ value, satisfaction and ability to researc h any product offering and making purchases wherever and whenever they wish. References Barlow, A.K.J., Siddiqui, N.Q., Mannion, M. (2004). Developments in information and communication technologies for retail marketing channels. International Journal of Retail Distribution Management, 32(3), 157-163. Bordonaba-Juste, V., Lucia-Palacios, L., Polo-Redondo, Y. (2012). Antecedents and consequences of e-business adoption for European retailers. Internet Research, 22(5), 532-550. Delgado, F.J. (2012). New retail technologies. Sporting Goods Business, 45(9), 10-13. Fiorito, S.S., Gable, M., Conseur, A. (2010). Technology: Advancing retail buyer performance in the 21st century. International Journal of Retail Distribution Management, 38(11/12), 879-893.Advertising Looking for assessment on business economics? Let's see if we can help you! Get your first paper with 15% OFF Learn More Ko, E., Kincade, D.H. (1997). The impact of quick response technologies on retail store attributes. International Journal of Retail Distribution Management, 25(2), 90-98. Puleri, J. (2011). The future of technology in retail. Chain Store Age, 87(7), 22-22.

Judgement at Nuremberg analysi essays

Judgement at Nuremberg analysi essays Nuremberg Trials were trials conducted to put the surviving prominent German leaders on trial for various "war crimes". These trials were conducted by the govenments of United States, Soviet Union, Britain and France. The movie Judgement at Nuremberg depicts one of these trials. It seems the movie makers intention was to show that the people in the Justice Department should also be put on trial for aiding the killings of millions of people. It seems it the movie makers were playing devils advocate. They were trying to convey that these killings were wrong and unjustful and that everybody involved with it should be found guilt ( as seen at the end of the movie that all Judges are found guilty). But also the arguments presented by the defense are strong that could show that the Justices on trial were innocent as they abidded to the law that the time in their country. The prosecution's opening statement states that the individuals on the trial are guilty. They reason that these people were educated, before Nazis came to power. They cannot claim innocence like the young people who were coopted into Nazism. They had power to prevent this. But the defense argues that though the judges were educated they do not make law, but intrepret it and carry it out. That's what these individuals did and now they were on trial. It doesn't matter if they think that it is wrong or right. It seems here the director is trying to send a message saying that the judges that followed the laws of their country it was ok to kill somebody due to their race. So saying that each country's or culture has their own code of conduct. Also the defense lawyer mentions that if these Justices are on trial then all the German people should also be on trial. The director also shows that judge sent to Nuremberg for this case was probably not the best of the available. As he had just lost the elections, and not much liked. The director seems to be questioning this. ...

Evaluate emerging trends in organizational behavior related to Essay

Evaluate emerging trends in organizational behavior related to high-performance workplaces and stress management techniques - Essay Example An organizational culture refers to a system of shared actions, values and beliefs that is present among the members of an organization. For example the corporate culture of Apple computers values the importance of innovation and creativity. Stress can be defined as tension from extraordinary demands, constraints, or opportunities (Schermerhorn, et al., 2003). There different stressors that cause stress in the workplace. Some of those stressors include task demands, ethical dilemmas, physical setting, and interpersonal problems. There are different techniques managers are using to deal with stress in the workplace. An emerging technique that is helping a lot of workers deal with stress is wellness programs. A wellness program involves maintaining a balance between physical and mental health. Providing the employees of a company with a gymnasium is an example of a wellness initiative that can help reduce stress in the workplace. People can reduce their stress by practicing relaxation techniques, meditation, or yoga. A simple way managers can help reduce stress in the workplace is by having several short breaks during a workday. References Schermerhorn, J., Hunt, J., Osborn, R. (2003). Organizational Behavior (8th ed.). New York: John Wiley & Sons.

What new problems arose for the Roman Empire during the first two Essay

What new problems arose for the Roman Empire during the first two centuries A.D - Essay Example lous reign of Augustus Caesar (63 B.C- 14 A.D), the empire underwent political and economic downturn under the Julio Claudio emperors; especially at the time of Nero (A.D 54-68). A major blaze devastated Rome in A.D 64 and subsequently Christians were brutally persecuted throughout the empire. It was followed by a number of rebellions until the emergence of Flavian dynasty. Although Vespasian (A.D 69-79) the first Flavian was a good ruler, Domitian (A.D 81-96) was brutal and notably inefficient. The period between A.D. 96 and A.D161 was comparatively peaceful under the emperors Nerva (A.D 96-98), Trajan (98-117), Hadrian (117-138), and Antonius Pius (138-161) respectively. Again the Empire fell in wars against Germanic tribes during the reign of Marcus Aurelius (A.D 161-180). His son and successor Commodus (180-192) being an unfaithful ruler left the great empire to terrible civil wars. The empire was literarily fragmented under various military groups and finally occupied by 7 different dynasties since 193 A.D. In short, during the first two centuries the Roman Empire experienced numerous

Office of Strategic Services Essay Example for Free

Office of Strategic Services Essay The Office of Strategic Services (OSS) was created on June 13, 1942 by President Franklin Roosevelt after he decided that he needed a new and different form of espionage group modeled after a British Intelligence agency. The primary reason for the OSS was to gather enemy information, carry out sabotage operations, distribute propaganda to attack the enemies and plan out special operations for different agencies. Willam J.  Donovan was the head of OSS appointed by President Roosevelt, who soon began to recruit everyone he thought was necessary for the job including, consulting, British spy-master Lan Fleming, author of the popular series James Bond. Donovan was born on January 1, 1883 and was a very successful man outside of all of his military duty. He was a lawyer and intelligence officer outside of the battlefield but also was a Colonel during WWI and reached Major General during WWII. Donovan was also named the Coordinator Of Information (COI) and received multiple medals for all of his service including: Distinguished Service Medal, three Oak Leaf Cluster Medals, a Medal of Honor (MOH) and three Purple Hearts. Donovan died on February 8, 1959 and is now a part of the Military Intelligence Hall of Fame. The OSS was formed from the COI but half of its members stayed to work with the government for the Foreign Information Service (FIS). When the OSS first began, many people didnt like the group because they thought it to be taking over and it was actually banned from all Japanese intercepts and was only allowed to certain German intercepts under FBI terms. The Counterintelligence unit (X-2) was only allowed to operate in the Eastern Hemisphere where the FBI was operated in the Western Hemisphere. However, the British Intelligence services were very helpful to the OSS, understanding what they were going through, British Intelligence helped with OSS training, information and experience. The OSS was separated into three different branches, The Research and Analysis Branch, The Moral Operations Branch and The Labor Division. The Research and Analysis Branch was responsible for employing academics for plan strategies for future invasions. The Moral Operations Branch was responsible for producing all of the propaganda used to attack enemies and The Labor Division was responsible for discouraging activity within trade unions. There were also three, main functional branches which were made of the Special Operations (SO), the Secret Intelligence (SI) and the Counterintelligence (X-2). Weapons and spy gear were a big part of the OSS and all of their success. Donovan created in-house capability to fabricate tools and weapons but by the end of the war there were multiple labs which created mass-productions of weapons and spy gear for all of the OSS to use. There was a Research and Development Branch which was the main-inventing station for all weapons and gadgets. Stanley P. Lovell was in charge of the Research and Development Branch. The OSS is now the Central Intelligence Agency (CIA) and has the most responsibilities that the OSS did during WWII. The functions of the OSS were split between the Department of State and the Department of War. The State Department received the Research and Analysis Branch of OSS which was renamed the Interim Research and Intelligence Service and the War Department took over the Secret Intelligence (SI) and Counter-espionage (X-2) Branches. The OSS was dissolved September 20, 1945 by President Truman. Over the years, the OSS conducted successful espionage and sabotage operations in Europe and Asia along with employing almost 13,000 men and women.

Herpes Essay -- essays research papers

Herpes Herpes is one of the common of more than 30 different sexually transmitted diseases (STD’s) in America today. Herpes is an infection that is caused by one of two closely related viruses, herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2). Both of which are very easily caught, have similar symptoms, and can occur on different parts of the body. Even though it is most common to see the virus HSV-1 appear as oral herpes and to see the virus HSV-2 appear as genital herpes.   Ã‚  Ã‚  Ã‚  Ã‚  Most often herpes is a relatively harmless disease that is rarely life threatening. The most common form of herpes is oral herpes and usually shows up on the lips or inside of the mouth as â€Å"cold sores† or â€Å"fever blisters†. Cold sores are common in young children who acquire them from being exposed to active cold sores of adults and other children. This form of herpes is annoying but harmless in both children and adult, but is however very harmful to a newborn. It can sometimes be difficult to distinguish whether or not someone has been exposed to the other form of herpes, genital herpes. This is because there are very often no symptoms that go along with the virus. This is not always the case though and when symptoms do occur they are often seen as a cluster of blister sores, usually on the vagina, vulva, cervix, penis, or anus. For genital herpes, symptoms may last several weeks, go away but only to return again weeks, months, or even year s later. Symptoms may a...

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Under this contract, the customer selects the capital equipment or property (assets) to be nuanced by the bank and the bank then purchases these assets from the manufacturer or supplier and then leases them to the customer for an agreed period. In conformity with the Shari's, the owner of the assets (in this case the bank) must be paid rent (fixed or variable, as agreed by the lesson and lessee) and must exercise all the rights and obligations that are incidental to ownership such as maintaining, insuring and repairing the assets.The lessee, on the other hand, obtains the use of the asset for the period of the lease subject to paying the rent. The lessee may assume the obligations, such as maintaining, insuring and repairing the asset, in return for a reduced rent. 1 . 3. 2 What is Car Ajar? As mentioned above ‘Jar is basically the transfer of suffuses (defined below) of a fixed asset to another person for an agreed period, for an agreed consideration. Under a Car ‘Jar ag reement the car will be rented to the customer for the period agreed at the time of contract.Upon completion of the lease period the customer in the Means case discussed below, gets ownership of the car against his initial security deposit. Car ‘Jar is a Shari's-compliant car-leasing scheme. It is based on the principles of Jar and is completely free from the element of interest. This product is designed for interpretative individuals, looking for a car-financing scheme that helps in avoiding interest-based transactions. So Car ‘Jar is simply a rental agreement under which the car will be given to the customer in exchange for rent for a period, agreed at the time of the contract.Means Bank, based in Pakistan and a pioneer in this area, purchases the car and rents it out to the customer for a period of three, four or five years. Upon completion of the lease period the customer gets ownership of the car against his initial security deposit. Somewhat confusingly, the Means Car ‘Jar scheme has elements of ‘Jar WA Satin within it. In this case study I propose to follow the Means assumption in using ‘Jar in the sense that it involves car ownership at the end of the maturity of the deal. This is in line with Shari's methodology and terminology. . 3. 2. 1 What is Suffuses? Suffuses is the right of enjoying a thing, the property of which is vested in another, and to draw from the same all the profit, utility and advantage that it may produce, provided it be without altering the substance of the thing. Items without suffuses cannot be leased. It is necessary for a valid lease contract that the corpus of the leased asset remains in the ownership of the seller, and only its suffuses is transferred to the lessee. 1 . 3. 3 In what Sense is Car ‘Jar Interest Free?In Car Ajar, the asset remains under the ownership and at the risk of the bank and the customer only pays the rental for the use of the asset, Just like the rent of a house. 3 Und er leasing or lease purchase, the Islamic financial institution buys the financed asset and retains the title through the life of the contract. The customer makes a series of lease payments over a specified period of time, and may have the option at the end to buy the item from the lesson (and owner) at a pre specified residual value. Leasing was not originally a mode of financing.It was simply a transaction meant to transfer the suffuses of a property from one person to another for an agreed period and an agreed upon consideration. Leasing can be used as a mode of financing, in Islamic banks, as an alternative to conventional car financing. However, the consideration of leasing as a mode of financing should be based on certain notations. It should be understood, by all using it as a mode of financing, that it is not sufficient to substitute the term ‘interest' with the term ‘rent', and use the term ‘mortgage' instead of the term ‘leased asset'.There must be a significant difference between leasing and an interest-bearing loan. It is no secret that an Islamic bank or financial institution will take into consideration the same factors as a conventional bank when determining the rental payments and residual value. These would include the rate of inflation, the creditworthiness of the Jesse, the opportunity cost value of the money (as reflected by market interest rates) and so on. An implicit ‘interest rate' can trivially be calculated from the price, residual value, term of the lease and the lease payment.This fact is not hidden. Indeed Muslim customers are encouraged to ‘shop around' and ensure that the Islamic financial institution is not implicitly charging an interest rate, which is in line with the conventional market. In the final analysis, however, the difference is in the form of the contract. If the lease is structured in accordance with the various conditions within Islamic Jurisprudence, t will contract no rib and e nsure that it cannot contain such forbidden rib in the future (e. G. In terms of late payment fees, etc. ). 1 . 3. 4 What is the Difference between a Conventional Lease and an Islamic Lease? The most important financial difference between Islamic leasing and conventional leasing is that, with Islamic leasing, the leasing agency must own the leased object for the duration of the lease. Therefore, although leasing a car from a car manufacturer or car dealership may in principle be permitted for Muslims (if the contract satisfies the other conditions), Muslims should investigate further.In many cases, the car dealership may in fact use a bank or other financial intermediary to provide a loan for the present value of lease payments, and charge the customer interest on this loan. This would constitute the forbidden rib. Scrupulous Islamic financial institutions ensure that the contract abides by all the restrictions set out in the Shari's (e. G. , subleasing requires the permission of th e lesson; late payment penalties must be handled very carefully to avoid rib, etc. ). The differences between conventional and Islamic financing schemes are described in he sections below. 1. 3. 4. Leasing versus Conventional Financing Conventional Financing The conventional financing schemes provide financing for purchasing a car; that is, in essence the financier is giving a loan and charging interest. 4 Islamic Financing The Islamic car financing – ‘Jar – is based on a lease contract. It is not a financing scheme; rather it is a lease contract. As mentioned earlier leasing is a contract whereby suffuses rights to an asset are transferred by the owner, known as the lesson, to another person, known as the lessee, at an agreed-upon price, called the .NET, and for an agreed-upon period of time, called the term of lease. . 3. 4. 2 Rentals versus Installments A conventional car financing scheme is actually an interest-based loan given by the financial institution, w ith interest being charged on the loan. Islamic car financing is based on pure rentals. In Car ‘Jar the asset remains at the ownership and risk of the bank and the customer only pays the rental for use of the asset, Just like the rent for a house. 1. 3. 4. 3 Ownership In conventional car financing, the car is purchased in the name of the buyer from the dealer. Islamic FinancingUnder ‘Jar the ownership remains with the bank; that is, the car is purchased from the dealer in the name of the bank. This is because it is one of the foremost conditions of the Islamic mode of leasing that an object cannot be leased out unless it is in the possession of the lesson. 1. 3. 4. 4 Risk/loss Since the car is bought in the name of the buyer in the traditional mode of car financing, the risk is immediately transferred to the buyer, whereas in the case of Islamic financing, this is not so. The car is purchased in the name of the bank from the dealer and so the risk mains entirely with the bank.As the corpus of the leased property remains in the ownership of the lesson, all the liabilities and risks emerging from the ownership are borne by the lesson. The lessee is responsible for any loss caused to the asset by misuse or negligence. The lessee can also be made liable for the wear and tear, which normally occurs during its use. But the lessee cannot be made liable for a loss caused by factors beyond his control. (The agreements CIO 5 with traditional car financing generally do not differentiate between these two situations.In a lease based on Islamic principles, both situations should be dealt with separately. 1. 3. 4. 5 Down-payment versus Security Deposit Both the down-payment and the security deposit are one-time payments. The major difference occurs because the buyer can buy back the car against the security deposit in the case of Ajar, whereas in conventional banking the down-payment remains with the bank, and no buy-back of the car can occur against the down- p ayment. With ‘Jar the buyer is required to keep a security deposit at the bank.There is a minimum and a maximum requirement for the security deposit. The requirement is efferent in the case of conventional car financing, where a down-payment is made by the buyer of the car. 1. 3. 4. 6 Return of the Car In a traditional car financing scheme, the customer takes out a loan to purchase the car, which he cannot return under any circumstances whatsoever, unless he pays off the loan. Islamic Financing In the Islamic mode of financing, the buyer has the right to return the car anytime during or at the end of the lease period.Since this is a lease agreement, and the lessee has been paying rentals, he can return the car to the bank and take back the security deposit any time he wishes. . 3. 4. 7 Termination of Contract The buyer of the car has the option and right to terminate the contract and return the car before the contract reaches its maturity in both the conventional and Islamic m ode of car financing. The difference lies in the post-termination phase. In the conventional car financing scheme, if the customer wants to terminate the contract the only option he has is to buy the car by paying the rest of the installments.In the Islamic car financing scheme, the customer has two options: either return the car and get back the security deposit or buy the car from the bank at the market alee plus a certain percentage of spread for the bank. 6 1. 3. 4. 8 Documentation Differences Sequence/process Islam considers the procedure in which any transaction takes place as a significant factor in all modes of financing. The underlying difference between the Islamic and conventional modes of financing is that of the process. To Muslims, not only the end result but also the means to it are important.If the result is correct and the steps are wrong, or vice versa, the entire process is deemed invalid, from a Shari's perspective. According to Shari's principles, lawful steps t o lawful results are very important. The most important financial difference between Islamic permitted leasing and conventional financial leasing is that the leasing agency must own the leased object for the duration of the lease. Ownership of the asset is the prerequisite for leasing out its suffuses. As mentioned, Islam places great emphasis on the sequencing. 1 . 3. The Means Bank Car ‘Jar Scheme Means Banks Car ‘Jar has been designed according to the principles of Islam and is completely interest-free. Moreover the ‘Jar contract and other documentation also comply with Shari's requirements. In contrast, a conventional car-financing scheme s actually an interest-based loan given by the financial institution with interest being charged on the loan. Also, in conventional car-leasing schemes, the lease contract is not in compliance with Shari's law and has rib and other UN-lilacs elements in it. 1. 3. 5. What Makes Car ‘Jar Unique? Some of the key characteris tics of the Means Car ‘Jar are described in the following sections. Rights and Liabilities of Owner Versus User ‘Jar is an asset-based contract, that is, the lesson should have ownership of the asset during the life of the contract. Under Shari's law all ownership-related rights and abilities should lie with the owners while all usage-related rights and liabilities should lie with the user. A conventional lease contract does not distinguish between the nature of these liabilities and dumps all liabilities on the user.This is not permitted under the Shari's. Under ‘Jar all ownership-related risks lie with the bank and all usage related links lie with the user, thus making the lesson the true owner of the asset and making the income generated through the contract permissible (hall) for the Islamic bank. Continuation of Lease Rentals in the Case of Total Loss or Theft of Vehicle If the eased vehicle is stolen or completely destroyed the conventional leasing company wo uld continue charging the lease holder rent until the settlement of the insurance claim.Under the Islamic system, however, rent is consideration for usage of the leased asset and, if the asset has been stolen or destroyed, the concept of rental becomes void. As such, in the above-mentioned eventualities, Means Bank does not charge the lease rental. Is there a Penalty for Late Payment of Rent? If so How is This Permissible Under the Shari's? In most conventional financial leases an extra monetary amount is charged if rent is to paid on time. This extra amount is considered as rib under the Shari's and is distinctly forbidden 7 (harm).The lessee may be asked to undertake that if he fails to pay rent on its due date, he will pay a certain amount to a charity that will be administered through the bank. For this purpose Means Bank maintains a charity fund where such amounts may be credited and disbursed for charitable purposes. What is the Insurance Arrangement under Car Ajar? Being the owner of the car, the bank will be responsible for insurance of the car and for paying the insurance premium. If Tactful (Islamic insurance) is not available, the insurance is done under the conventional system.Can the User Buy the Car Prior to the Termination of Rental Agreement? Yes. The rental agreement contains the purchase price schedule. Is the Product Approved by Means Banks Shari's Board Yes. Car ‘Jar is designed under the supervision of Means Banks Shari's Supervisory Board and is approved by the Board. In order for any Islamic financing technique to be acceptable to the Islamic community it has to be endorsed by the appropriate Shari's Board who will provide a Fatwa (a religious ruling). The appendix to this case illustrates the Fatwa applicable to the Means Bank Car ‘Jar agreement.

The Environment, what are the issues?

It is a fair assessment to say that as a race we humans have not really cared for our environment as well as we could have. As a world we face some major changes to the environment, which can be looked at in three main reason. 1. Increases in the World's population. There has been a major increase in the amount of people who live on the planet. It is estimated that the population has increased by over 75 million per year. That means that it has been predicted that by 2050 the world population is expected to be at 9 billion. 2. The increased use of natural resources, which cannot be replaced. Due to advances in technology we are becoming more reliant on them. We are using up natural resources (like coal, oil and wood) to turn them into energy (like electricity). When these resources are used, they change the environment. They are making by ~ products like carbon monoxide and toxic chemicals. 3. People want more material things than ever before. People who live in countries like ours have a higher standard of living and expect to have a comfortable lifestyle. People who live in less economically developed countries want the same lifestyle. How are people interacting with the environment? If we all lived with the same attitudes to the world, we would not be facing the issues we are today. But we know that every one of us has a different set of priorities and as such are exploiting the environment to achieve our own aims. If we look at the Tropical rainforests we can see this in action. The tropical rainforests cover up to a third of the world's surface. My species of animals live there and many of them are unique to that area. If one area is changed / damaged this will have a knock on effect to the rest of the world. If you like it is a kind of jigsaw that fits together. When one piece is missing, the eco system is not complete. The trees in the rainforests are important for a number of reasons: 1. Trees absorb carbon dioxide and produce oxygen. 2. Without forests radiation bounces back into the atmosphere raising the temperatures. 3. This could alter the air circulation (convection). 4. It is also involved in recycling the water in the earth to return as rainfall in other parts of the world. 5. Streams will disappear if the forests are not there to store the water. This is happening now in parts of Africa!

Trust essays

Trust essays Lack of trust is a reoccurring theme through out the three cases. One might ask, why you need trust in any civil society? Lack of trust in a civil society has the society with no real stability. Trust in authority is lacking in each case. The approval rating for Bill Clinton is high. Does this mean that most Americans trust Bill Cliton? Most polls would tell that trust is a serious issue. So, what is the consequences of Americans not having trust in there president? It cant be to bad because the economy is doing great and the budget and finally balanced. Most Americans are happy so what is the problem? The lack of trust is a direct correlation with weak and/or illegitimate authority. Trust with our president has always been a sensitive issue. Richard Nixion broke that trust with the country and sealed the fate for himself and his party for a short term. No one really understood why Nixon had ordered the break in of the democratic offices in the first place. What made matters worse is Nixion never came out and admitted his mistake even when the evidence was overwhelming. Clintons case has some similarities to it. While he finally did come out and admit what he had done he showed little remorse and accusations still remain about a cover up. The lack of trust in a political position in this country tends to the norm. It is created and redefined every day in Washington with a political figure. This creates an image and a strong stereotype for all political figures. This in turn hurts all of our civil society. Without the trust then how do you have the legitimate authority to lead the country. Most would say that Clintons leadership really is not the question but his judgment is. To me, that is a contradiction and that poor judgment leads to poor leadership. His poor judgment leads to his ethics and morals that he has. People with weak family values will have a hard time tru ...

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Financing Education Equitably & Sources of Revenue Essay

Financing Education Equitably & Sources of Revenue - Essay Example But are these funds enough to cater for the rising population? The issue of funds allocation in the education system has over the years been debatable. 1. In the modern century, several trends have come up which detects the mode of allocation and expenditure of the funds. In general the trends are developed to determine the school district wealth. One of the most used methods is the determining of the state’s current operating expenditure per pupil (COEPP). The measurement covers expenditure on curriculum materials and teacher’s salaries. It is also inclusive of administration and student’s transportation charges. Generally, it detects the difference in expenditure costs per children in different regions of the country. This trend however provides a good field to fraud the government. According to Brimley & Rulon (2008) the trend can be easily fraud by increasing the totals in the expenditures which will provide unnecessary inequality. Another trend is the assump tion of activities and projects to be undertaken by a school at the start of every educational year. These assumptions are obtained from the regional school calendar. The calendar contains all the possible events of the year and their financial estimates. Apart from the activities there is also the determination of possible curriculum changes. The teachers’ funds are also included in the estimates. The estimates and assumptions are close to accurate which provides less probability for great deficits. After the allocation of these funds the regional schools are provided with surplus cash which will cover small adjustments in the course of the year. With these allocations, there is prior planning and management of these funds and school projects. However, if in the course of the year there are major adjustments it could be difficult for regions to tackle the issues. Another shortcoming is that schools may be forced to stick to a particular program and curriculum thus preventing elasticity (Brimley & Rulon, 2008). 2 a. Equity: This is the financial benefits of investors after all liabilities have been accounted for. In educational matters if refers to the benefits the students will have from allocation of funds. Generally, it can be referred to the value of an institution or organization’s assets after all debts and liabilities have been cleared. b. Regressive tax: This is a tax whereby the taxation rate reduces while the amount subject to taxation increases. c. Proportional tax: This is tax whereby the tax rate remained fixed. The amount subject to taxation is directly proportional to the amount of the tax. d. Progressive tax: this is a tax imposed whereby the tax rate increases while the amount subject to taxation also increases. e. Tennessee Basic Education Program (BEP): this is a money generating and funding program whereby state education funds are generated and distributed to Tennessee schools. f. ADA: It is the acronym of Average Daily Atten dance. The average student attendance helps in the determining of allocation of funds. ADA is calculated by the number of days of school attendance by a student divided by the number of the days teachers taught in the school (Brimley & Rulon, 2008). For example, if Isaac attended 142 days of the total 142 of teaching days, he has a 1.0 ADA. g. ADM: it the acronym of Average Daily Membership. This is the count of residential and state based

Australian painting, colony to nation Essay Example | Topics and Well Written Essays - 3000 words

Australian painting, colony to nation - Essay Example The essay "Australian painting, colony to nation" discovers the Australian landscape paintings. Landscape art is an art form that depicts the natural beauty of the scenery. This art involves the capturing of features like mountains, rivers, valleys, forests among many others. On the other hand, contemporary arts are works of art from during the post World War II period to date. The Australian Aboriginal art describes the artistic aspects of the indigenous people of Australia whose way of life was nomadic uncivilized. In short, all these forms of art complement one another in describing what Australian historic art entails. They bring out the evolution of art in this isolated island nation that is rich and wealthy. Therefore, this essay will seek to bring out the history of landscape art in Australia in a sense that it was not a progressive discovery. It will blend ideas on the establishment of changing concepts in building pictures that are more appropriate. It will also the cultural construction that tend to out play one another in the complexity of invention web. Since the pre-colonial period, art has been a way of preserving a community’s heritage and pride. The techniques varied between different communities in the world. The artists in these societies used the locally available materials to try to express their concepts. Over the years, civilization led to the improvement in the doing of arts. For instance, during the Paleolithic age the people used to do their paintings or works of art. in walls of caves that existed in their vicinity. These magnificent art works exist to date in museums and cultural heritage sites. Most of them are thousand and thousand years old, but they still portray the way of living for people in that era (Sayers, 2001:19). These paintings have helped archaeologists in writing the history of their nations as they give documented evidence. In essence, the history of art in Australia is no different from the histories of other countries as the stages it took in evolution are relatively the same to the others. Ideally, the art market in the traditional times strongly believed in oil paintings in representing landscapes of Australia. However, contemporary art over took the oil paintings within the domestic market paving way for international accreditation for artistes from Australia (Coombes, 2006:23). With the focus on landscape painting, the Australian landscape is one guided by notions of beauty, style, and decor. The landscape paintings by artists from Australia depicted their artistic tastes and preferences. In essence, paintings do not speak, but they tend to communicate. The expressions within a painting need to have a proper arrangement to depict its social relations to power. The communicative aspect and the social aspect need not separated as they will detract the meaning hidden in the painting (Short, 2005:197). Ideally, landscape painting is a highly selective process meaning that only the eleme nts that are of essence get to select to be part of the painting. However, emphasize is also on some key aspects that trend to portray the meaning of the scenery in question. Essentially, these paintings provide a relation between them and the original landscape where drawn. Remarkably, some foreign painters also managed to paint out the landscapes in Australia despite the fact

Bullying Essay Example | Topics and Well Written Essays - 750 words - 3

Bullying - Essay Example All of this came about because of one simple thing: I was teased. The experience of being bullied, even though it was not very intense, had a profound effect on my life after that point. Indeed, bullying is one of the most devastating social experiences many children, teens, and young adults face across the world today. According to the American Academy of Child and Adolescent Psychiatry, fully half of all children in public school systems will experience some sort of bullying at some point in their lives. This bullying can range from verbal teasing, as I experienced, to much more vicious physical and emotional abuse that can have a serious impact on the victim’s mental and physical well-being. Bullying during a child’s teenage years can take a heavy toll, and lead to depression, drug use, and stunted social development well into that person’s adult life. In severe cases, the victim may even commit suicide. As technology advances and more people become users of social media websites such as Facebook or MySpace, a new type of bullying has emerged. This is cyber-bullying, the use of virtual tools or places to insult and degrade a victim instead of doing it in person. This can be as simple as a text message, or as complicated as creating a fake social network account and making the victim believe you are their friend, before cruelly insulting them and utterly destroying their faith in other human beings. This was the case with Megan Meier, who hanged herself after the mother of one of her friends created a fake account and pretend to be a boy she liked, only to constantly insult her and tell her she was worthless. Clearly, then, bullying of all sorts is a serious problem. It is not only a problem I myself has experienced, but one which affects communities the world over. It is also a problem which communities need to tackle as communities, and not as individuals. There are several ways

Tobacco Targeting Children Essay Example for Free

Tobacco Targeting Children Essay Tobacco is one of the main products that affect our children today. Companies that distribute these products do not think about who is getting affected by their product, but think about the profit they will make from selling their product. Big companies like Philip Morris who sell Marlboro, Basic, Virginia Slim and many other types of tobacco target young adults. Gene Emery quoted the amount spent on tobacco advertising is targeting youngsters. Some points Gene Emery presents are quiet different than what I believe. From working at my previous store that I owned in Sacramento, during these eight years, I didnt recognize some of the points Gene Emery brings out. Gene Emery suggests that they found the amount spent to advertise three brands popular with young people- Camel, Marlboro and Newport- in youth-oriented magazines increased immediately. The first point I would like to point out is that Gene Emery targets young people and also said that brands for adult-oriented products like Basic, Winston or Virginia Slims spend less money on advertising because they target only adults. He says that certain products are for young people while some are for adults. The way he presented his idea was false because from my past experience, I have realized that Newport cigarettes targets African Americans, Marlboro targets originally Asians, Camel cigarettes targets construction workers, Virginia Slim targets women and Basic targets the less fortunate who cant buy Marlboro. Dont get me wrong that I am defend the tobacco companies, I am actually against this. Philip Morris spend more money on ads for Marlboro than Basic because Marlboro is more popular and brings in more profit than Basic does. When we deal with children, we have to be cautious about everything we do. Some adults who smoke, do not realize that their children are getting affected by them. Gene Emery believes that the advertising is to blame. I am agreeing with him, but we should not also forget the family actions in front of their children. In order to prevent our children to smoke, we should start at home. The parents have a great responsibility to act right in front of their kids like put out the cigarette they see their child coming through the door or to try to even stop smoking. I was raised with a family that does not smoke. We are eight girls and one boy and still none of us smoke till now because my family knew how to act and set the perfect role model for us. I am trying to do the same thing for my two boys. I tell them that smoking is awful and it makes you sick and die and whenever they see somebody smoking they say that this person is stupid because he is hurting himself. The laws in this country protects our children; in order for oneself to buy any tobacco, they have to be 18 years of age or older. There is also an agreement to stop promoting cigarettes to children. This agreement was passed in 1998. Attached to this paper is the lawsuit to control tobacco companies. Also, attached to this paper is an article that differs the US laws with other country like Australia and Britain. In my country, the government supports tobacco companies. Ads are placed everywhere about tobaccos, places like TVs, radios, in the street, magazine covers and they also made candys for kids that looks like cigarettes. I believe that the American children are lucky to have such great laws to protect them and that anybody can sue them if something went wrong. Difficult as it may be for tobacco control advocates to demand accountability, tobacco control programs will not survive if the nongovernmental organizations that care about the program will not protect it. The preservation of the intent and spirit of these programs will not occur simply because an initiative is approved by the voters. This approval is a powerful force, but it must be used effectively by those who accept the responsibility for defending the public interest. Exercising oversight over the elected and appointed officials who had authority over the tobacco control program was even more challenging for the public health groups than getting the program enacted. In the years immediately following an election or legislative action to create a tobacco control program, the effort to keep the will of the voters before the Legislature is not difficult, since both the press and the public are likely to be paying attention. But voter approval is likely to become less obvious and thus less powerful over time, and tobacco control advocates need to seek ways to keep the public informed and involved on the tobacco issue. If advocates instead retreat to playing only the insider political game, they will probably fail. They must be willing to withstand and embrace the controversy that the tobacco industry and its allies will generate. Appendix B Important California Tobacco Control Events April 1977 Berkeley passes an indoor air ordinance. November 1978 Proposition 5 (statewide initiative covering clean indoor air and Research Accounts until 1996, passes. SB 493 sought to issues) is defeated. November 1980 Proposition 10 (statewide initiative covering clean indoor air issues) is defeated. December 1980 Californians for Nonsmokers Rights forms to pass local clean indoor air ordinances. November 1983 Proposition P (San Francisco referendum) is defeated; smoke-free workplace law remains on the books. November 1988 Proposition 99 (statewide initiative) passes.

Existentialism in Albert Camus The Plague and Samuel Becketts Waiting

All of the characters in The Plague and Waiting For Godot exist in their fictional worlds. However, none is able to explain why. Neither work gives the reader an explanation of human existence except to say that humans exist. Providing an answer to the question of existence would constitute a paradox. To an existentialist, if you answer the question, then you've missed the whole point. Existentialism is a philosophy that emphasizes the uniqueness and isolation of the individual experience in a hostile or indifferent universe, regards human existence as unexplainable, and stresses freedom of choice and responsibility for the consequences of one's acts (Bigelow 134). Basically, existentialism addresses man's existence. An existentialist believes that man does not exist under God or as part of a society or race. Man does exist, and that is all. An explanation as to why man exists cannot be found. Finally, an individual exists not as a function of a greater good or evil; thus, the individual is free to live his life (135). Existentialism as a literary movement is most often associated with post World War II France. The images that come to mind are of Frenchmen with uncombed beards, smoky basement cafes, and beatniks conversing with one another on the subject of despair between sips of absinthe. However, many of the most prominent existentialist writers had rigorous and significant experiences in the Resistance during the Nazi occupation of France (Lottman 54). Out of true despair they formed ideas and posed questions of great importance. They sought to understand and explain human existence. They concluded that existence is to be acknowledged, but can never be explained. Two existentialist works are Samuel Beckett's Waiti... ... them to reevaluate their relations to others and to question their own existence. At first, most citizens assume that they will not get the plague, but they soon realize that even they are not immune to it. In this way they question their own humanity and are faced with something bigger than they have ever contemplated. They, like Vladimir and Estragon, are unable to come up with answers. All of the characters in The Plague and Waiting For Godot exist in their fictional worlds. However, none is able to explain why. Neither work gives the reader an explanation of human existence except to say that humans exist. Providing an answer to the question of existence would constitute a paradox. To an existentialist, if you answer the question, then you've missed the whole point. The key is in asking the question. The realization is in accepting that there is no answer

Internet and Intranet Connectivity Through Wireless Local Area Network (Wlan)

CHAPTER 1 Introduction Chapter 1 Introduction 1. 1 What is WLAN? 1. 1. 1 WLAN Wireless Local Area Network (WLAN) is a kind of local area network which established using a wireless link between the service providers and the clients using some wireless equipment. This network development is based on the IEEE 802. 11 standard. 1. 1. 2 IEEE 802. 11 IEEE 802. 11 denotes a set of Wireless LAN/WLAN standards developed by working group 11 of the IEEE LAN/MAN Standards Committee (IEEE 802). The term 802. 11x is also used to denote this set of standards and is not to be mistaken for any one of its elements. There is no single 802. 1x standard. The term IEEE 802. 11 is also used to refer to the original 802. 11, which is now sometimes called â€Å"802. 11 legacy† [1]. The 802. 11 family currently includes six over-the-air modulation techniques that all use the same protocol. The most popular techniques are those defined by the b, a, and g amendments to the original standard; security was originally included and was later enhanced via the 802. 11i amendment. 802. 11n is another modulation technique that has recently been developed; the standard is still under development, although products designed based on draft versions of the standard are being sold. Other standards in the family (c–f, h, and j) are service enhancements and extensions or corrections to previous specifications. 802. 11b was the first widely accepted wireless networking standard, followed by 802. 11a and 802. 11g [1]. 802. 11b and 802. 11g standards use the 2. 40 GHz (gigahertz) band, operating (in the United States) under Part 15 of the FCC Rules and Regulations. Because of this choice of frequency band, 802. 11b and 802. 11g equipment can incur interference from microwave ovens, cordless telephones, Bluetooth devices, and other appliances using this same band. The 802. 1a standard uses the 5 GHz band, and is therefore not affected by products operating on the 2. 4 GHz band. Table 1. 1: Protocol Summary of IEEE 802. 11 Protocol Legacy 802. 11a 802. 11b 802. 11g 802. 11n Release Date 1997 1999 1999 2003 2006 Operating Frequency GHz 2. 4-2. 5 5 2. 4-2. 5 2. 4-2. 5 2. 4 and/or 5 Throughput (Typ) Mbps 0. 7 23 4 19 74 Data Rate (Max) Mbps 2 54 11 54 248 = 2Ãâ€" 2 ant Range (Indoor) meters ~25 ~30 ~35 ~35 ~70 Range (Outdoor) meters ~75 ~100 ~110 ~115 ~160 2 1. 2 Why it should be used? Bangladesh entered the Internet world in 1993 using offline E-mail services. Online Dial-up services started in 1996 through VSAT based data connectivity. But it is not possible to give a Dial-up connection to all because; it uses the BTTB’s telephone line. While Dial-up is active the phone line is busy and it is not possible to give a client more than 4/5 Kbps speed. Using an ADSL modem it can be increased to more than 2 Mbps. But it is not enough for a corporate user and also it is very costly and there are many other problems which has described below. The Ethernet connectivity can give a maximum of 100 Mbps. But its range is too small. Wireless LAN has vast benefits over wired network in some aspects. In our country especially in big cities like Dhaka, it is very hard job to establish a wired network all over the city. Because, it is over populated, buildings were made with out any proper plan and also the roads. Generally the wire lines are established over head, which is not so secured. Wire can be broken due to any kind of natural or man made problem. It may be theft. Or it can be misused by any one by taking a parallel line from it. It may create leak of data security. It is also very expensive to establish a copper wire network road by road and maintenance of it. Besides that there are many rivers, cannels in our county, and also hill tracks in some parts. It is not possible to give a wired network over those. For all those reasons it is not a wise decision to use a wired network in our country. A Wireless LAN can be more reliable, low cost, convenient network considering above aspects. There are a number of Internet Service Provider (ISP) companies in our country giving Wireless LAN support to the clients. Those are known as Wireless ISP. These ISPs give internet or intranet service to the clients as their requirements. Those networks are reliable and also secured. It is easy to establish a connection in the company’s coverage area using a wireless device at the client end. The Wireless ISP Company should have proper resources to give that coverage. A model of a Wireless ISP company’s wireless part for Bangladesh is given below. The nation wide link can be a optical fiber or microwave link. Here the main coverage is shown in Dhaka city and thus BSSs are shown at here is more than one. It can be expand the network in other areas by adding additional equipments required to establish a BSS. And also it can give coverage on other areas by establish same network on that area. Figure 1. 1: Model of a Wireless ISP 1. 3 Why one should be interested in WLAN field? The telecom industry is changing with breathtaking speed. There are a lot of telecommunication and Wireless ISP companies working in our country and there are a lot of companies to come. At present telecommunication is the most challenging and interesting field out of all other e ngineering fields. All the telecom company has some common structure. So, there are many similarities between a mobile or PSTN (Public Switched Telephone Network) operator and a Wireless ISP. The skills one gather from a Wireless ISP can use in the telecom companies. The man can be skilled on installing different devices, surveying a site, proposing a link budget. He can face the practical problems occur in installing radio networks and can be skilled in solving those problems and also troubleshoot the devices and the radio link. In the mobile operators, there are many restrictions. One can not work with all things. But as still Wireless ISP companies are smaller in our country one can get opportunity to work in different sections which will increase his experiences and skills. Lastly it can be say that, as it is a challenging field, the person likes facing challenges will enjoy working in this field 4 1. 4 Organization of this report This Internship report has seven chapters in total. The second chapter contains theory about the radio frequency properties and different modulation techniques In third chapter, different RF antennas and it accessories are described. Fourth chapter contains the Wireless LAN’s theory and architecture in brief. Chapter five analyzes to survey a site, and how to budget a link. The sixth chapter describes the device installation process for the APERTO and CANOPY devices. The seventh and final chapter is the concluding chapter where limitations of this works are reported and few suggestions of our work are provided along with the concluding remarks. 1. 5 Aims and objectives 5 RF Properties and Modulation Techniques CHAPTER 2 6 Chapter 2 RF Properties and Modulation Techniques 2. 1 Radio Frequency 2. 2. 1 Radio Frequency Radio frequencies are high frequency alternating current (AC) signals that are passed along a copper conductor and then radiated into the air via an antenna. An antenna converts/transforms a wired signal to a wireless signal and vice versa. When the high frequency AC signal is radiated into the air, it forms radio waves. These radio waves propagate (move) away from the source (the antenna) in a straight line in all directions at once. 2. 2. 2 RF Behaviors RF is sometimes referred to as â€Å"smoke and mirrors† because RF seems to act erratically and inconsistently under given circumstances. Things as small as a connector not being tight enough or a slight impedance mismatch on the line can cause erratic behavior and undesirable results. The following sections describe these types of behaviors and what can happen to radio waves as they are transmitted. Gain Gain, illustrated in Figure 2. 1, is the term used to describe an increase in an RF signal' amplitude [2]. Gain is usually an active process; meaning that an external s power source, such as an RF amplifier, is used to amplify the signal or a high-gain antenna is used to focus the beam width of a signal to increase its signal amplitude. Figure 2. 1: Power gain However, passive processes can also cause gain. For example, reflected RF signals combine with the main signal to increase the main signal' strength. Increasing the RF s signal' strength may have a positive or a negative result. Typically, more power is s better, but there are cases, such as when a transmitter is radiating power very close to legal power output limit, where added power would be a serious problem. 7 Loss Loss describes a decrease in signal strength (Figure 2. 2). Many things can cause RF signal loss, both while the signal is still in the cable as a high frequency AC electrical signal and when the signal is propagated as radio waves through the air by the antenna. Resistance of cables and connectors causes loss due to the converting of the AC signal to heat. Impedance mismatches in the cables and connectors can cause power to be reflected back toward the source, which can cause signal degradation. Objects directly in the propagated wave' transmission path can absorb, reflect, or s destroy RF signals. Loss can be intentionally injected into a circuit with an RF attenuator. RF attenuators are accurate resistors that convert high frequency AC to heat in order to reduce signal amplitude at that point in the circuit. [2] Figure 2. 2: Power loss Being able to measure and compensate for loss in an RF connection or circuit is important because radios have a receive sensitivity threshold. A sensitivity threshold defined as the point at which a radio can clearly distinguish a signal from background noise. Since a receiver’s sensitivity is finite, the transmitting station must transmit signal with enough amplitude to be recognizable at the receiver. If losses occur between the transmitter and receiver, the problem must be corrected either by removing the objects causing loss or by increasing the transmission power. Reflection Reflection, (as illustrated in Figure 2. 3) occurs when a propagating electromagnetic wave impinges upon an object that has very large dimensions when compared to the wavelength of the propagating wave [3]. Reflections occur from the surface of the earth, buildings, walls, and many other obstacles. If the surface is smooth, the reflected signal may remain intact, though there is some loss due to absorption and scattering of the signal. Figure 2. 3: Reflection 8 RF signal reflection can cause serious problems for wireless LANs. This reflecting main signal from many objects in the area of the transmission is referred to as multipath. Multipath can have severe adverse affects on a wireless LAN, such as degrading or canceling the main signal and causing oles or gaps in the RF coverage area. Surfaces such as lakes, metal roofs, metal blinds, metal doors, and others can cause severe reflection, and hence, multipath. Reflection of this magnitude is never desirable and typically requires special functionality (antenna diversity) within the wireless LAN hardware to compensate for it. Refraction Refraction describes the bending of a radio wave as it passes through a medium of different density. A s an RF wave passes into a denser medium (like a pool of cold air lying in a valley) the wave will be bent such that its direction changes. When passing through such a medium, some of the wave will be reflected away from the intended signal path, and some will be bent through the medium in another direction, as illustrated in Figure 2. 4. [3] Figure 2. 4: Refraction Refraction can become a problem for long distance RF links. As atmospheric conditions change, the RF waves may change direction, diverting the signal away from the intended Diffraction Diffraction occurs when the radio path between the transmitter and receiver is obstructed by a surface that has sharp irregularities or an otherwise rough surface [3]. At high frequencies, diffraction, like reflection, depends on the geometry of the obstructing object and the amplitude, phase, and polarization of the incident wave at the point of diffraction. Diffraction is commonly confused with and improperly used interchangeably with refraction. Care should be taken not to confuse these terms. Diffraction describes a wave bending around an obstacle (Figure 2. 5), whereas refraction describes a wave bending through a medium. Taking the rock in the pond example from above, now consider a small twig sticking up through the surface of the water near where the rock. As the ripples hit the stick, they would be blocked to a small degree, but to a larger degree, the ripples would bend around the twig. This illustration shows how diffraction acts with obstacles in its path, depending on the makeup of the obstacle. If Object was large or jagged enough, the wave might not bend, but rather might be blocked. 9 Figure 2. 5: Diffraction Diffraction is the slowing of the wave front at the point where the wave front strikes an obstacle, while the rest of the wave front maintains the same speed of propagation. Diffraction is the effect of waves turning, or bending, around the obstacle. As another example, consider a machine blowing a steady stream of smoke. The smoke would flow straight until an obstacle entered its path. Introducing a large wooden block into the smoke stream would cause the smoke to curl around the corners of the block causing a noticeable degradation in the smoke' velocity at that point and a significant s change in direction. Scattering Scattering occurs when the medium through which the wave travels consists of objects with dimensions that are small compared to the wavelength of the signal, and the number of obstacles per unit volume is large [3]. Scattered waves are produced by rough surfaces, small objects, or by other irregularities in the signal path, as can be seen in Figure 2. 6. Figure 2. 6: Scattering Some outdoor examples of objects that can cause scattering in a mobile communications system include foliage, street signs, and lampposts. Scattering can take place in two primary ways. First, scattering can occur when a wave strikes an uneven surface and is reflected in many directions simultaneously. Scattering of this type yields many small amplitude reflections and destroys the main RF signal. Dissipation of an RF signal may occur when an RF wave is reflected off sand, rocks, or other jagged surfaces. When scattered in this manner, RF signal degradation can be significant to the point of intermittently disrupting communications or causing complete signal loss. 10 Second, scattering can occur as a signal wave travels through particles in the medium such as heavy dust content. In this case, rather than being reflected off an uneven surface, the RF waves are individually reflected on a very small scale off tiny particles. Voltage Standing Wave Ratio (VSWR) VSWR occurs when there is mismatched impedance (resistance to current flow, measured in Ohms) between devices in an RF system. VSWR is caused by an RF signal reflected at a point of impedance mismatch in the signal path. VSWR causes return loss which is defined as the loss of forward energy through a system due to some of the power being reflected back towards the transmitter. If the impedances of the ends of a connection do not match, then the maximum amount of the transmitted power will not be received at the antenna. When part of the RF signal is reflected back toward the transmitter, the signal level on the line varies instead of being steady. This variance is an indicator of VSWR. [2] As an illustration of VSWR, imagine water flowing through two garden hoses. As long as the two hoses are the same diameter, water flows through them seamlessly. If the hose connected to the faucet were significantly larger than the next hose down the line, there would be backpressure on the faucet and even at the connection between the two hoses. This standing backpressure illustrates VSWR, as can be seen in Figure 2. . In this example, you can see that backpressure can have negative effects and not nearly as much water is transferred to the second hose as there would have been with matching hoses screwed together properly. Figure 2. 7: VSWR-like water through a hose VSWR Measurements VSWR is a ratio, so it is expressed as a relationship between two numbers. A typical VSWR value would be 1. 5:1. The two numbers re late the ratio of impedance mismatch against a perfect impedance match. The second number is always 1, representing the perfect match, where as the first number varies. The lower the first number (closer to 1), the better impedance matching your system has. For example, a VSWR of 1. 1:1 is better than 1. 4:1. A VSWR measurement of 1:1 would denote a perfect impedance match and no voltage standing wave would be present in the signal path. Effects of VSWR Excessive VSWR can cause serious problems in an RF circuit. Most of the time, the result is a marked decrease in the amplitude of the transmitted RF signal. However, 11 since some transmitters are not protected against power being applied (or returned) to the transmitter output circuit, the reflected power can burn ut the electronics of the transmitter. VSWR' effects are evident when transmitter circuits burn out, power s output levels are unstable, and the power observed is significantly different from the expected power. The methods of changing VSWR in a circuit include proper use of proper equipment. Tight connections between cables and connectors, use of impedance matched hardware throughout, and use of high-quality equipment with calibration reports where necessary are all good preventative measures against VSWR. VSWR can be measured with high-accuracy instrumentation such as SWR meters, but this measurement is beyond the scope of this text and the job tasks of a network administrator. 2. 2 Spread Spectrum 2. 2. 1 Spread Spectrum Spread spectrum is a communications technique characterized by wide bandwidth and low peak power. Spread spectrum communication uses various modulation techniques in wireless LANs and possesses many advantages over its precursor, narrow band communication [4]. Spread spectrum signals are noise-like, hard to detect, and even harder to intercept or demodulate without the proper equipment. Jamming and interference have a lesser affect on a spread spectrum communication than on narrow band communications. For these reasons, spread spectrum has long been a favorite of the military. 2. 2. 2 Narrow Band Transmission A narrowband transmission is a communications technology that uses only enough of the frequency spectrum to carry the data signal and no more, spread spectrum is in opposition to that mission since it uses much wider frequency bands than is necessary to transmit the information. This brings us to the first requirement for a signal to be considered spread spectrum. A signal is a spread spectrum signal when the bandwidth is much wider than what is required to send the information. [4] Figure 2. 8 illustrates the difference between narrowband and spread spectrum transmissions. One of the characteristics of narrow band is high peak power. More power is required to send a transmission when using a smaller frequency range. In order for narrow band signals to be received, they must stand out above the general level of noise, called the noise floor, by a significant amount. Because its band is so narrow, and high peak power ensures error-free reception of a narrow band signal. 12 Figure 2. 8: Narrow band verses Spread Spectrum on a frequency domain A compelling argument against narrowband transmission-other than the high peak power required to send it-is that narrow band signals can be jammed or experience interference very easily. Jamming is the intentional overpowering of a transmission using unwanted signals transmitted on the same band. Because its band is so narrow, other narrow band signals, including noise, can completely eliminate the information by overpowering a narrowband transmission; much like a passing train overpowers a quiet conversation. 2. 2. 3 Spread Spectrum Technology Spread spectrum technology allows taking the same amount of information than previously using a narrow band carrier signal and spreading it out over a much larger frequency range. For example, 1 MHz at 10 Watts with narrow band, but 20 MHz at 100 mW with spread spectrum. By using a wider frequency spectrum, we reduce the probability that the data will be corrupted or jammed. A narrow band jamming attempt on a spread spectrum signal would likely be thwarted by virtue of only a small part of the information falling into the narrow band signal' frequency range. s s Most of the digital data would be received error-free [4]. Today' spread spectrum RF radios can retransmit any small amount of data loss due to narrowband interference. While the spread spectrum band is relatively wide, the peak power of the signal is quite low. This is the second requirement for a signal to be considered spread spectrum. For a signal to be considered spread spectrum, it must use low power. These two characteristics of spread spectrum (use of a wide band of frequencies and very low power) make it look to most receivers as if it were a noise signal. Noise is a wide band, low power signal, but the difference is that noise is unwanted. Furthermore, since most radio receivers will view the spread spectrum signal as noise, these receivers will not attempt to demodulate or interpret it, creating a slightly more secure communication. 2. 2. 4 Frequency Hopping Spread Spectrum (FHSS) Frequency hopping spread spectrum is a spread spectrum technique that uses frequency agility to spread the data over more than 83 MHz. Frequency agility refers to the radio’s ability to change transmission frequency abruptly within the usable RF frequency band [4]. In the case of frequency hopping wireless LANs, the usable portion of the 2. GHz ISM band is 83. 5 MHz, per FCC regulation and the IEEE 802. 11 standard. 13 How FHSS Works In frequency hopping systems, the carrier changes frequency, or hops, according to a pseudorandom sequence. The pseudorandom sequence is a list of several frequencies to which the carrier will hop at specified time intervals before repeating the pattern. The transmitter uses this hop sequence to select it s transmission frequencies. The carrier will remain at a certain frequency for a specified time (known as the dwell time), and then use a small amount of time to hop to the next frequency (hop time). When the list of frequencies has been exhausted, the transmitter will repeat the sequence. Figure 2. 9 shows a frequency hopping system using a hop sequence of five frequencies over 5 MHz band. In this example, the sequence is: 1. 2. 449 GHz 2. 2. 452 GHz 3. 2. 448 GHz 4. 2. 450 GHz 5. 2. 451 GHz Figure 2. 9: Single frequency hopping system Once the radio has transmitted the information on the 2. 451 GHz carrier, the radio will repeat the hop sequence, starting again at 2. 449 GHz. The process of repeating the sequence will continue until the information is received completely. The receiver radio is synchronized to the transmitting radio' hop sequence in order to s receive on the proper frequency at the proper time. The signal is then demodulated and used by the receiving computer. Effects of Narrow Band Interference Frequency hopping is a method of sending data where the transmission and receiving systems hop along a repeatable pattern of frequencies together. As is the case with all spread spectrum technologies, frequency hopping systems are resistant-but not immune-to narrow band interference. In example in Figure 2. 9, if a signal were to interfere with our frequency hopping signal on, say, 2. 51 GHz, only that portion of the spread spectrum signal would be lost. The rest of the spread spectrum signal would remain intact, and the lost data would be retransmitted. 14 In reality, an interfering narrow band signal may occupy several megahertz of bandwidth. Since a frequency hopping band is over 83 MHz wide, even this interfering signal will cause little de gradation of the spread spectrum signal. Frequency Hopping Systems The IEEE and Open-Air standards regarding FHSS systems describe: 1. The frequency bands which may be used 2. Hop sequences 3. Dwell times 4. Data rates The IEEE 802. 1 standard specifies data rates of 1 Mbps and 2 Mbps and Open-Air (a standard created by the now defunct Wireless LAN Interoperability Forum) specifies data rates of 800 kbps and 1. 6 Mbps. In order for a frequency hopping system to be 802. 11 or Open-Air compliant, it must operate in the 2. 4 GHz ISM band (which is defined by the FCC as being from 2. 4000 GHz to 2. 5000 GHz). Both standards allow operation in the range of 2. 4000 GHz to 2. 4835 GHz. Channels A frequency hopping system will operate using a specified hop pattern called a channel. Frequency hopping systems typically use the FCC’s 26 standard hop patterns or a subset thereof. Some frequency hopping systems will allow custom hop patterns to be created, and others even allow synchronization between systems to completely eliminate collisions in a co-located environment. Figure 2. 10: Co-located frequency hopping system Though it is possible to have as many as 79 synchronized, co-located access points, with this many systems, each frequency hopping radio would require precise synchronization with all of the others in order not to interfere with (transmit on the same frequency as) another frequency hopping radio in the area. The cost of such a set of systems is prohibitive and is generally not considered an option. If synchronized radios are used, the expense tends to dictate 12 co-located systems as the maximum. 15 If non-synchronized radios are to be used, then 26 systems can be co-located in a wireless LAN; this number is considered to be the maximum in a medium-traffic wireless LAN. Increasing the traffic significantly or routinely transferring large files places the practical limit on the number of co-located systems at about 15. More than 15 co-located frequency-hopping systems in this environment will interfere to the extent that collisions will begin to reduce the aggregate throughput of the wireless LAN. Dwell Time In frequency hopping systems, it must transmit on a specified frequency for a time, and then hop to a different frequency to continue transmitting. When a frequency hopping system transmits on a frequency, it must do so for a specified amount of time. This time is called the dwell time. Once the dwell time has expired, the system will switch to a different frequency and begin to transmit again. Suppose a frequency hopping system transmits on only two frequencies, 2. 401 GHz and 2. 402 GHz. The system will transmit on the 2. 01 GHz frequency for the duration of the dwell time100 milliseconds (ms), for example. After 100ms the radio must change its transmitter frequency to 2. 402 GHz and send information at that frequency for 100ms. Hop Time When considering the hopping action of a frequency hopping radio, dwell time is only part of the story. When a frequency hopping radio jumps from frequency A to frequency B, it must change the transmit frequency in one of two ways. It ei ther must switch to a different circuit tuned to the new frequency, or it must change some element of the current circuit in order to tune to the new frequency. In either case, the process of changing to the new frequency must be complete before transmission can resume, and this change takes time due to electrical latencies inherent in the circuitry. There is a small amount of time during this frequency change in which the radio is not transmitting called the hop time. The hop time is measured in microseconds ( µs) and with relatively long dwell times of around 100-200 ms, the hop time is not significant. A typical 802. 11 FHSS system hops between channels in 200-300  µs. With very short dwell times of 500 – 600 µs, like those being used in some frequency hopping systems such as Bluetooth, hop ime can become very significant. If we look at the effect of hop time in terms of data throughput, we discover that the longer the hop time in relation to the dwell time, the slower the data rate of bits being transmitted. 2. 2. 5 Direct Sequence Spread Spectrum (DSSS) Direct sequence spread spectrum is very widely known and the most used of the spread spectrum types, owing most of its popularity to its ease of implementation and high data rates. The majority of wireless LAN equipment on the market today uses DSSS technology. DSSS is a method of sending data in which the transmitting and receiving systems are both on a 22 MHz-wide set of frequencies. The wide channel enables devices to transmit more information at a higher data rate than current FHSS systems. 16 How DSSS Works DSSS combines a data signal at the sending station with a higher data rate bit sequence, which is referred to as a chipping code or processing gain. A high processing gain increases the signal’s resistance to interference. The minimum linear processing gain that the FCC allows is 10, and most commercial products operate under 20. The IEEE 802. 11 working group has set their minimum processing gain requirements at 11. The process of direct sequence begins with a carrier being modulated with a code sequence. The number of–chips-in the code will determine how much spreading occurs, and the number of chips per bit and the speed of the code (in chips per second) will determine the data rate. Direct Sequence Spread Spectrum (DSSS) Direct sequence spread spectrum is very widely known and the most used of the spread spectrum types, owing most of its popularity to its ease of implementation and high data rates. The majority of wireless LAN equipment on the market today uses DSSS technology. DSSS is a method of sending data in which the transmitting and receiving systems are both on a 22 MHz-wide set of frequencies. The wide channel enables devices to transmit more information at a higher data rate than current FHSS systems. How DSSS Works DSSS combines a data signal at the sending station with a higher data rate bit sequence, which is referred to as a chipping code or processing gain. A high processing gain increases the signal’s resistance to interference. The minimum linear processing gain that the FCC allows is 10, and most commercial products operate under 20. The IEEE 802. 11 working group has set their minimum processing gain requirements at 11. The process of direct sequence begins with a carrier being modulated with a code sequence. The number of-chips-in the code will determine how much spreading occurs, and the number of chips per bit and the speed of the code (in chips per second) will determine the data rate. Channels Unlike frequency hopping systems that use hop sequences to define the channels, direct sequence systems use a more conventional definition of channels. Each channel is a contiguous band of frequencies 22 MHz wide and 1 MHz carrier frequencies are used just as with FHSS. Channel 1, for instance, operates from 2. 401 GHz to 2. 423 GHz (2. 412 GHz  ± 11 MHz); channel 2 operates from 2. 406 to 2. 429 GHz (2. 417  ± 11 MHz), and so forth. Figure 2. 11 illustrates this point. 17 Figure 2. 11: channel allocation and Spectral relationship The chart in Table 2. 1 has a complete list of channels used in the United States and Europe. The FCC specifies only 11 channels for non-licensed use in the United States. Each of the frequencies listed in this chart are considered center frequencies. From this center frequency, 11 MHz is added and subtracted to get the useable 22 MHz wide channel. Easy to see that adjacent channels (channels directly next to each other) would overlap significantly. Table 2. 1: DSSS channel frequency Assignment Channel ID 1 2 3 4 5 6 7 8 9 10 11 FCC Channel Frequencies GHz 2. 412 2. 417 2. 422 2. 427 2. 432 2. 437 2. 442 2. 447 2. 452 2. 457 2. 462 ETSI Channel Frequencies GHz N/A N/A 2. 422 2. 427 2. 432 2. 437 2. 442 2. 447 2. 452 2. 457 2. 462 To use DSSS systems with overlapping channels in the same physical space would cause interference between the systems. DSSS systems with overlapping channels should not be co-located because there will almost always be a drastic or complete reduction in throughput. Because the center frequencies are 5 MHz apart and the channels are 22 MHz wide, channels should be co-located only if the channel numbers are at least five apart: channels 1 and 6 do not overlap, channels 2 and 7 do not overlap, etc. There is a maximum of three co-located direct sequence systems possible because channels 1, 6 and 11 are the only theoretically non-overlapping channels. The 3 non-overlapping channels are illustrated in Figure 2. 2 18 Figure 2. 12: DSSS non-overlapping Channel 2. 2. 6 Comparing FHSS and DSSS Both FHSS and DSSS technologies have their advantages and disadvantages, and it incumbent on the wireless LAN administrator to give each its due weight when deciding how to implement a wireless LAN [4]. This section will cover some of the factors that should be discussed when determining which technology is appropriate f or your organization, including: 1. Narrowband interference 2. Co-location 3. Cost 4. Equipment compatibility 5. Data rate and throughput 6. Security 7. Standards support Narrowband Interference The advantages of FHSS include a greater resistance to narrow band interference. DSSS systems may be affected by narrow band interference more than FHSS because of the use of 22 MHz wide contiguous bands instead of the 79 MHz used by FHSS. This fact may be a serious consideration if the proposed wireless LAN site is in an environment that has such interference present. Co-location An advantage of FHSS over DSSS is the ability for many more frequency hopping systems to be co-located than direct sequence systems. Since frequency hopping systems are-frequency agile-and make use of 79 discrete channels, frequency hopping systems have a co-location advantage over direct sequence systems, which have a maximum co- location of 3 access points. 19 Figure 2. 13: Co-location Comparison However, when calculating the hardware costs of an FHSS system to get the same throughput as a DSSS system, the advantage quickly disappears. Because DSSS can have 3 co-located access points, the maximum throughput for this configuration would be: 3 access points ? 1 Mbps = 33 Mbps At roughly 50% of rated bandwidth, the DSSS system throughput would be approximately: 33 Mbps / 2 = 16. 5 Mbps To achieve roughly the same rated system bandwidth using an IEEE 802. 11 compliant FHSS system would require: 16 access points ? 2 Mbps = 32 Mbps At roughly 50% of rated bandwidth, the FHSS system throughput would be approximately: 32 Mbps / 2 = 16 Mbps In this configuration, an FHSS system would require 13 additional access points t o be purchased to get the same throughput as the DSSS system. Also, additional installation services for these units, cables, connectors, and antennas would all need to be purchased. Cost: When implementing a wireless LAN, the advantages of DSSS may be more compelling than those of FHSS systems, particularly when driven by a tight budget. The cost of implementing a direct sequence system is far less than that of a frequency hopping system. DSSS equipment is widely available in today’s marketplace, and its rapid adoption has helped in driving down the cost. Only a few short years ago, equipment was only affordable by enterprise customers. Today, very good quality 802. 11b compliant PC cards can be purchased for under $100. FHSS cards complying with either the 802. 11 or Open-Air standards typically run between $150 and $350 in today' market depending on the manufacturer and the standards to which the cards s adhere. 20 Equipment compatibility and availability The Wireless Ethernet Compatibility Alliance (WECA) provides testing of 802. 11b compliant DSSS wireless LAN equipment to ensure that such equipment will operate in the presence of and interoperate with other 802. 11b DSSS devices. The interoperability standard that WECA created and now uses is called Wireless Fidelity, or Wi-Fi, and hose devices that pass the tests for interoperability are-Wi-Fi compliant-devices. Devices so deemed are allowed to affix the Wi-Fi logo on the related marketing material and devices themselves showing that they have been tested and interoperate with other Wi-Fi compliant devices. There are no such compatibility tests for equipment that uses FHSS. There are standards such as 802. 11 and Open-Air, but no organization h as stepped forward to do the same kind of compatibility testing for FHSS as WECA does for DSSS. Due to the immense popularity of 802. 11b compliant radios, it is much easier to obtain these units. The demand seems only to be growing for the Wi-Fi compliant radios while the demand for FHSS radios has remained fairly steady, even decreasing to some degree over the past year. Data rate and throughput The latest frequency hopping systems are slower than the latest DSSS systems mostly because their data rate is only 2 Mbps. Though some FHSS systems operate at 3 Mbps or more, these systems are not 802. 11 compliant and may not interoperate with other FHSS systems. FHSS and DSSS systems have a throughput (data actually sent) of only about half of the data rate. When testing the throughput of a new wireless LAN installation, achieving 5-6 Mbps on the 11 Mbps setting for DSSS or 1 Mbps on the 2 Mbps setting common using DSSS. When wireless frames are transmitted, there are pauses between data frames for control signals and other overhead tasks. With frequency hopping systems, this interframe spacing is longer than that used by direct sequence systems, causing a slow-down in rate that data is actually sent (throughput). Additionally, when the frequency hopping system is in the process of changing the transmit frequency, no data is sent. This translates to more lost throughput, albeit only a minor amount. Some wireless LAN systems use proprietary physical layer protocols in order to increase throughput. These methods work, yielding throughputs as high as 80% of the data rate, but in so doing, sacrifice interoperability. Security: It is widely touted-and is a myth-that frequency hopping systems are inherently more secure than direct sequence systems. The first fact that disproves this myth is that FHSS radios are only produced by a minimal number of manufacturers. Of this small list of manufacturers, all of them adhere to standards such as 802. 1 or Open-Air in order to sell their products effectively. Second, each of these manufacturers uses a standard set of hop sequences, which generally comply with a pre-determined list, produced by the standards body (IEEE or WLIF). These 2 items together make breaking the code of hop sequences relatively simple. 21 Other reasons that make finding the hop sequence quite simple is that the channel number is broadcasted in the clear with each beacon. Also, the MAC address of the transmitting access point can be seen with each beacon (which indicates the manufacturer of the radio). Some manufacturers allow the administrator the flexibility of defining custom hopping patterns. However, even this custom capability is no level of security since fairly unsophisticated devices such as spectrum analyzers and a standard laptop computer can be used to track the hopping pattern of a FHSS radio in a matter of seconds. Standards Support: DSSS has gained wide acceptance due to low cost, high speed, WECA' Wi-Fi s interoperability standards, and many other factors. This market acceptance will only accelerate due to the industry moving toward newer, faster DSSS systems such as the new 802. 1g and 802. 11a compliant wireless LAN hardware. WECA' new Wi-Fi5 s interoperability standard for 5 GHz DSSS systems operating in the UNII bands will help move the industry along even faster in the same direction it is already headed. The new standards for FHSS systems include Home RF 2. 0 and 802. 15 (in support of WPANs such as Bluetooth), but none for advancing FHSS systems in the enterp rise. 2. 2. 7 BPSK In BPSK, the phase of the carrier is varied to represent binary 1 or 0 . Both peak amplitude and frequencies remain constant as the phase changes. For example, if a phase of 0 represents binary 0, then the phase 180 represents binary 1. the phase of the signal during each bit duration is constant. And its value depends on the bit (0 or 1). Figure 2. 14 shows a conceptual view of BPSK. BPSK is also known as 2-PSK. because two different phases (0 and 180) are used. The table below shows BPSK which makes the relationship of phase to bit value. Bit 0 1 Phase 0? 180? Figure 2. 14: BPSK. 2. 2. 8 QPSK The diagram for the signal is given in Figure 2. 15. A phase of 0 now represents 00; 90 represents 01; 180 represents10; and 270 represents 11. This technique is called QPSK. The pair of bits represented by each phase is called a dibit. 22 Bit 00 01 10 11 Figure 2. 15: QPSK. Phase 0? 90? 180? 270? 2. 2. 9 QAM QAM is a Combination of ASK and PSK so that a maximum contrast between each signal unit (bit, dibit, tribit, and so on) is achieved. QAM takes the advantages of the fact that it is possible to send two different signals simultaneously on the same carrier frequency . by using two copies of the carrier frequency. One shifted by 90 with respect to the other. For QAM, each carrier is ASK modulated. The two independent signals are simultaneously transmitted over the same medium. In QAM the number of amplitude shifts is fewer than the number of phase shifts. Because amplitude changes are susceptible to noise and require greater shift distances than do phase changes, the number of phase shifts used by a QAM system is always larger than the number of amplitude shifts. [5] Figure 2. 16: QAM. 23 2. 2. 10 Orthogonal Frequency division Multiplexing (OFDM) Orthogonal Frequency division Multiplexing offers the highest data rates and maximum resistance to interference and corruption of all the signal manipulation techniques in use in 802. 1 today [5]. Although it is not considered a spread spectrum technique by the FCC, OFDM shares many qualities with spread spectrum communicators, including using a low transmit power and wider-than-necessary bandwidth. OFDM is used to provide data rates up to 54 Mbps in 802. 11a and 802. 11g. How OFDM Works OFDM achieves high data rates by squeezing a large number of Communication Channels into a given frequency band. Normally, two c ommunication channels must be separated by a certain amount of bandwidth or they overlap and interfere. Specially, each Channel has harmonics that extend up and down the frequency space, decreasing in amplitude as they get farther from the channels fundamental signal. Even if two channels are non-overlapping, their harmonics may overlap and the signal can be corrupted. An OFDM communicator can place adjacent communication channels very precisely in the frequency space in such a way that the channels harmonics exactly cancel each other, effectively leaving only the fundamental signals. OFDM achieves high data rates by dividing a single communication channel into a large number of closely-spaced, small bandwidth sub-carriers. Each sub-carrier individually has a relatively low data rate, but by transmitting data in parallel on all sub-carriers simultaneously, high data rates can be achieved. Figure 2. 17: OFDM frequency plot. Figure 2. 17 shows an example of a frequency spectrum for an OFDM transmitter. Each of the peaks represents a single sub-carrier, and the sub-carriers together make up the communications channel. The sub-carriers are precisely aligned so that the zero-points of their harmonics overlapped exactly. The majority of the harmonic energy will cancel out, leaving just the sub-carriers. 4 CHAPTER 3 RF Antenna and Accessories 25 Chapter 3 RF Antenna and Accessories 3. 1 Introduction Antennas are most often used to increase the range of wireless LAN systems, but proper antenna selection can also enhance the security of your wireless LAN. A properly chosen and positioned antenna can reduce the signal leaking out of workspace, and make signal interception extremely difficult. 3. 2 RF Antennas An RF antenna is a device used to convert high frequency (RF) signals on a transmission line (a cable or waveguide) into propagated waves in the air [6]. The electrical fields emitted from antennas are called beams or lobes. Antenna convert electrical energy into RF waves in the case of a transmitting antenna, or RF waves into electrical energy in the case of a receiving antenna. The physical dimensions of an antenna, such as its length, are directly related to the frequency at which the antenna can propagate waves or receive propagated waves. The physical structure of an antenna is directly related to the Shape of the area in which it concentrates most of its related RF energy. There are three generic categories of RF antennas: 1. Omni-directional 2. Semi-directional 3. Highly-directional Each category has multiple types of antennas, each having different RF characteristics and appropriate uses. As the gain of an antenna goes up, the coverage area narrows so that high-gain antennas offer longer coverage areas than low-gain antennas at the same input power level. 3. 2. 1 Omni-directional (Dipole) Antennas The dipole is an omni- directional antenna, because it radiates its energy equally in all directions around its axis. Dipole antenna is Simple to design; dipole antenna is standard equipment on most access points. Directional antennas concentrate their energy into a cone, known as a â€Å"beam. † Figure 3. 1: Dipole doughnut 26 Figure 3. 1 shows that the dipole' radiant energy is concentrated into a region that s looks like a doughnut, with the dipole vertically through the â€Å"hole† of the â€Å"doughnut. † The signal from an omni-directional antenna radiates in a 360-degree horizontal beam. If an antenna radiates in all directions equally (forming a sphere), it is called an isotropic radiator, which is the theoretical reference for antennas, but rather, practical antennas all have some type of gain over that of an isotropic radiator. The dipole radiates equally in all directions around its axis, but does not radiate along the length of the wire itself – hence the doughnut pattern. The side view of a dipole radiator as it radiates waves in Figure 3. 2. Figure 3. 2: Dipole-side view If a dipole antenna is placed in the center of a single floor of a multistory building, most of its energy will be radiated along the length of that floor, with some significant fraction sent to the floors above and below the access point. Figure 3. 3 shows examples of some different types of omni-directional antennas. Figure 3. 3: Sample omni-directional antenna Figure 3. 4 shows a two-dimensional example of the top view and side view of a dipole antenna. Figure 3. 4: Coverage area of an omni-directional antenna High-gain omni-directional antennas offer more horizontal coverage area, but the vertical coverage area is reduced, as can be seen in Figure 3. 5. 27 Figure 3. 5: Coverage area of high gain omni-directional antennas This characteristic can be an important consideration when mounting a high-gain omni antenna indoors on the ceiling. If the ceiling is too high; the coverage area may not reach the floor, where the users are located. Usages Omni-directional antennas are used when coverage in all directions around the horizontal axis of the antenna is required. Omni-directional antennas are most effective where large coverage areas are needed around a central point. For example, placing an omni- directional antenna in the middle of a large, open room would provide good coverage. Omni-directional antennas are commonly used for point-tomultipoint designs with a hub-n-spoke topology. Used outdoors, an omni-directional antenna should be placed on top of a structure (such as a building) in the middle of the Figure 3. 6: Point to multipoint link coverage area. For example, on a college campus the antenna might be placed in the center of the campus for the greatest coverage area. When used indoors, the antenna should be placed at the middle of the building or desired coverage area, near the ceiling, for optimum coverage. Omni-directional antennas emit a large coverage area in a circular pattern and are suitable for warehouses or tradeshows where coverage is usually from one corner of the building to the other. 3. 2. 2 Semi directional Antenna Semi directional antennas direct the energy from the transmitter significantly more in one particular direction rather than the uniform circular pattern that is common with the omni- directional antenna; Semi-directional antennas come in many different styles and shapes. Some semi- directional antennas types frequently used with wireless LANs are Patch, Panel, and Yagi (pronounced â€Å"YAH-gee†) antennas. All of these antennas are generally flat and designed for wall mounting. Each type has different coverage characteristics. Figure 3. shows some examples of semidirectional antennas. 28 Figure 3. 7: Sample semi-directional antenna Semi-directional antennas often radiate in a hemispherical or cylindrical coverage pattern as can be seen in Figure 3. 8. Figure 3. 8: Coverage area of a semi-directional antenna Usages Semi-directional antennas are ideally suited for short and medium range bridging. For example, two office buildings that are across the street from one another and n eed to share a network connection would be a good scenario in which to implement semidirectional antennas. In a large indoor space, if the transmitter must be located in the corner or at the end of a building, a corridor, or a large room, a semi-directional antenna would be a good choice to provide the proper coverage. Figure 3. 9 illustrates a link between two buildings using semi-directional antennas. Figure 3. 9: Point to point link using semi-directional antenna In some cases, semi-directional antennas provide such long-range coverage that they may eliminate the need for multiple access points in a building. For example, in a long hallway, several access points with omni antennas may be used or perhaps only one or two access points with properly placed semi-directional antennas – saving the customer a significant amount of money. In some cases, semi- directional antennas have back and side lobes that, if used effectively, may further reduce the need for additional access points. 29 3. 2. 3 Highly directional antenna Highly-directional antennas emit the most narrow signal beam of any antenna type and have the greatest gain of these three groups of antennas. Highly-directional antennas are typically concave, dish-shaped devices, as can be seen Figures 3. 10 and 3. 11. These antennas are ideal for long distance, point-to-point wireless links. Some models are referred to as parabolic dishes because they resemble small satellite dishes. Others are called grid antennas due to their perforated design for resistance to wind loading. Figure 3. 10: sample of a highly directional antenna Figure 3. 11: sample of a highly directional grid antenna Figure 3. 12: Radiation pattern of a highly directional antenna Usages High-gain antennas do not have a coverage area that client devices can use. These antennas are used for point-to-point communication links, and can transmit at distances up to 25 miles. Potential uses of highly directional antennas might be to connect two buildings that are miles away from each other but have no obstructions in their path. Additionally, these antennas can be aimed directly at each other within a building in order to â€Å"blast† through an obstruction. This setup would be used in order to get network connectivity to places that cannot be wired and where normal wireless networks will not work. 0 3. 2. 4 Antenna Gain An antenna element without the amplifiers and filters typically associated with it is a passive device. There is no conditioning, amplifying, or manipulating of the signal by the antenna element itself. The antenna can create the effect of amplification by virtue of its physical shape. Antenna amplification is the result of focusing the RF ra diation into a tighter beam, just as the bulb of a flashlight can be focused into a tighter beam creating a seemingly brighter light source that sends the light further. The focusing of the radiation Measured by way of beam widths, which are measured in degrees horizontal and vertical. For example, an omni-directional antenna has a 360-degree horizontal beam width. By limiting the 360-degree beam width into a more focused beam of, say, 30 degrees, at the same power, the RF waves will be radiated further. This is how patch, panel, and Yagi antennas (all of which are semi-directional antennas) are designed. Highly directional antennas take this theory a step further by very tightly focusing both horizontal and vertical beam widths to maximize distance of the propagated wave at low power. . 2. 5 Intentional Radiator As defined by the Federal Communication Commission (FCC), an intentional radiator is an RF device that is specifically designed to generate and radiate RF signals. In terms of hardware, an intentional radiator will include the RF device and all cabling and connectors up to, but not including, the antenna, as illustrated in Figure 3. 13 below . Figure 3. 13: Intentional Radiator Any reference to â€Å"power output of the Intentional Radiator† refers to the power output at the end of the last cable or connector before the antenna. For example, consider a 30- milliwatt transmitter that loses 15 milliwatts of power in the cable and another 5 milliwatts from the connector at the antenna. The power at the intentional radiator would be 10 milliwatts. As an administrator, it is your responsibility to understand the FCC rules relating to Intentional Radiators and their power output. Understanding how power output is measured, how much power is allowed, and how to calculate these values are all covered in this book. FCC regulations concerning output power at the Intentional Radiator and EIRP are found in Part 47 CFR, 1 3. 2. 6 Equivalent Isotropically Radiated Power (EIRP) EIRP is the power actually radiated by the antenna element, as shown in Figure 3. 14. This concept is important because it is regulated by the FCC and because it is used in calculating whether or not a wireless link is viable. EIRP takes into account the gain of the antenna. Figure 3. 14: Equivalent Isotropically Radiated Power Suppose a transmittin g station uses a 10-dBi antenna (which amplifies the signal 10fold) and is fed by 100 mill watts from the intentional radiator. The EIRP is 1000 mW, or 1 Watt. The FCC has rules defining both the power output at the intentional radiator and the antenna element. 3. 3 RF Accessories When wireless LAN devices connect together, the appropriate cables and accessories need to purchase that will maximize throughput, minimize signal loss, and, most importantly, allow making connections correctly. Different types of accessories are needed in a wireless LAN design. [7] 1. RF Amplifiers 2. RF Attenuators 3. Lightning Arrestors 4. RF Connectors 5. RF Cables 3. 3. 1 RF Amplifiers An RF amplifier is used to amplify, or increase the amplitude of, RF signal, which is measured in +dB. An amplifier will be used when compensating the loss incurred by the RF signal, either due to the distance between antennas or the length of cable from a wireless infrastructure device to its antenna. Most RF amplifiers used with wireless LANs are powered using DC voltage fed onto the RF cable with an injector near the RF signal source (such as the access point or bridge). Sometimes this DC voltage used to power RF amplifiers is called â€Å"phantom voltage† because the RF amplifier seems to magically power up. This DC injector is powered using AC voltage from a wall outlet, so it might be located in a wiring closet. In this scenario, the RF cable carries 32 both the high frequency RF signal and the DC voltage necessary to power the in-line amplifier, which, in turn, boosts the RF signal amplitude. Figure 3. 15 shows an example of an RF amplifier (left), and how an RF amplifier is mounted on a pole (right) between the access point and its antenna. Figure 3. 15: A sample of a fixed gain Amplifier RF amplifiers come in two types: unidirectional and bi-directional. Unidirectional amplifiers compensate for the signal loss incurred over long RF cables by increasing the signal level before it is injected into the transmitting antenna. Bi-directional amplifiers boost the effective sensitivity of the receiving antenna by amplifying the received signal before it is fed into the access point, bridge, or client device. Configuration and Management RF amplifiers used with wireless LANs are installed in series with the main signal path seen below in Figure 3. 16. Amplifiers are typically mounted to a solid surface using screws through the amplifier’s flange plates. Configuration of RF amplifiers is not generally required unless the amplifier is a variable RF amplifier. If the amplifier is variable, the amplifier must be configured for the proper amount of amplification required, according to RF math calculations. The manufacturer' user manual will s explain how to program or configure the amplifier. Figure 3. 16: RF amplifier placement in the wireless LAN system 3. 3. 2 RF Attenuators An RF attenuator is a device that causes precisely measured loss (in dB) in an RF signal. While an amplifier will increase the RF signal, an attenuator will decrease it. Consider the case where an access point has a fixed output of 100mW, and the only antenna available is an omni-directional antenna with +20 dBi gain. Using this equipment together would violate FCC rules for power output, so an attenuator could be added to decrease the RF signal down to 30mW before it entered the antenna. This configuration would put the power output within FCC parameters. Figure 3. 17 shows examples of fixed-loss RF attenuators with BNC connectors (left) and SMA connectors (right). Figure 3. 18 shows an example of an RF step attenuator. 33 Figure 3. 7: Sample of a fixed loss Amplifier Figure 3. 18: A sample of a RF step attenuator (Variable loss) Configuration and Management Figure 3. 19 shows the proper placement in a wireless LAN for an RF attenuator, which is directly in series with the main signal path. Fixed, coaxial attenuators are connected directly between any two-connection points between the transmitter and the antenna. For example, a fixed, coaxial antenn a might be connected directly on the output of an access point, at the input to the antenna, or anywhere between these two points if multiple RF cables are used. Variable antennas are generally mounted to a surface with screws through their flange plates or simply placed in a wiring closet on a shelf. Configuration of RF attenuators is not required unless a variable attenuator is used, in which case, the amount of attenuation required is configured according to your RF calculations. Configuration instructions for any particular attenuator will be included in the manufacturer' user manual. s Figure 3. 19: RF attenuator placement in a wireless LAN 3. 3. 3 Lightning Arrestors A lightning arrestor is used to shunt transient current into the ground that is caused by lightning. Lightning arrestors are used for protecting wireless LAN hardware such as access points, bridges, and workgroup bridges that are attached to a coaxial transmission line. Coaxial transmission lines are susceptible to surges from nearby lightning strikes. Lightning arrestor are only needed for outdoor antennas that are 34 Susceptible to lighting sticks in the vicinity. They are not necessary for indoor antennas because of the existing building ground. A lightning arrestor can generally shunt surges up to 5000 Amperes at up to 50 volts. Lightning arrestor performs the following function 1. Lightning strikes a nearby object 2. Transient current are induced in the antenna or the RF transmission line 3. The lightning arrestor senses these currents and immediately ionizes the gases held internally to cause a short (a path of almost no resistance) directly to earth ground. Figure 3. 20: Lightning Arrestors installed in a network 3. 3. 4 RF Connectors RF connectors are specific types of connection devices used to connect cables to devices or devices to devices. Traditionally, N, F, SMA, BNC, and TNC connectors (or derivatives) have been used for RF connectors on wireless LANs. In 1994, the FCC and DOC (Canadian Department of Communications) ruled that connectors for use with wireless LAN devices should be proprietary between manufacturers [7]. For this reason, many variations on each connector type exist such as: 1. N-type 2. Reverse polarity N-type 3. Reverse threaded N-type Figure 3. 21: Sample N-type and SMA Connector 35 Choosing an RF Connector There are five things that should be considered when purchasing and installing any RF connector, and they are similar in nature to the criteria for choosing RF amplifiers and attenuators. . The RF connector should match the impedance of all other wireless LAN components (generally 50 ohms). 2. Know how much insertion loss each connector inserted into the signal path causes. The amount of loss caused will factor into your calculations for signal strength required and distance allowed. 3. Know the upper frequency limit (frequency response) specified for the particular connectors. This point will be very important as 5 GHz wireless LANs become more and more common. Some connectors are rated only as high as 3 GHz, which is fine for use with 2. GHz wireless LANs, but will not work for 5 GHz wireless LANs. Some connectors are rated only up to 1 GHz and will not work with wireless LANs at all, other than legacy 900 MHz wireless LANs. 4. Beware of bad quality connectors. First, always consider purchasing from a reputable company. Second, purchase only high-quality connectors made by name-brand manufacturers. This kind of purchasing particularity will help eliminate many problems with sporadic RF signals, VSWR, and bad connections. 5. Make sure you know both the type of connector (N, F, SMA, etc. ) that you need and the sex of the connector. Connectors come in male and female. Male connectors have a center pin, and female connectors have a center receptacle. 3. 3. 5 RF Cables Proper cables are needed for connecting an antenna to an access point or wireless bridge. Below are some criteria to be considered in choosing the proper cables for your wireless network. 1. Cables introduce loss into a wireless LAN, so make sure the shortest cable length necessary is used. 2. Plan to purchase pre-cut lengths of cable with pre-installed connectors. Doing minimizes the possibility of bad connections between the connector and the cable. Professional manufacturing practices are almost always superior to cables manufactured by untrained individuals. 3. Look for the lowest loss cable available at your particular price range (the lower the loss, the more expensive the cable). Cables are typically rated for loss in dB/100-feet. The table in Figure 5. 29 illustrates the loss that is introduced by adding cables to a wireless LAN. 4. Purchase cable that has the same impedance as all of your other wireless LAN components (generally 50 ohms). 5. The frequency response of the cable should be considered as a primary decision factor in your purchase. With 2. 4 GHz wireless LANs, a cable with a rating of at least 2. 5 GHz should be used. With 5 GHz wireless LANs, a cable with a rating of at least 6 GHz should be used. 36 Table 3. 1: Coaxial Cable attenuation ratings LMR Cable 100A 195 200 240 300 400 400UF 500 600 600UF 900 1200 1700 30 3. 9 2. 0 1. 8 1. 3 1. 1 0. 7 0. 8 0. 54 0. 42 0. 48 0. 29 0. 21 0. 15 50 5. 1 2. 6 2. 3 1. 7 1. 4 0. 9 1. 1 0. 70 0. 55 0. 63 0. 37 0. 27 0. 19 150 8. 9 4. 4 4. 0 3. 0 2. 4 1. 5 1. 7 1. 2 1. 0 1. 15 0. 66 0. 48 0. 35 220 10. 9 5. 4 4. 8 3. 7 2. 9 1. 9 2. 2 1. 5 1. 2 1. 0. 80 0. 59 0. 43 450 15. 8 7. 8 7. 0 5. 3 4. 2 2. 7 3. 1 2. 2 1. 7 2. 0 1. 17 0. 89 0. 63 900 22. 8 11. 1 9. 9 7. 6 6. 1 3. 9 4. 5 3. 1 2. 5 2. 9 1. 70 1. 3 0. 94 1500 30. 1 14. 5 12. 9 9. 9 7. 9 5. 1 5. 9 4. 1 3. 3 3. 8 2. 24 1. 7 1. 3 1800 33. 2 16. 0 14. 2 10. 9 8. 7 5. 7 6. 6 4. 6 3. 7 4. 3 2. 48 1. 9 1. 4 2000 35. 2 16. 9 15. 0 11. 5 9. 2 6. 0 6. 9 4. 8 3. 9 4. 5 2. 63 2. 0 1. 5 2500 39. 8 19. 0 16. 9 12. 9 10. 4 6. 8 7. 8 5. 5 4. 4 5. 1 2. 98 2. 3 1. 7 37 CHAPTER 4 Wireless LAN 38 Chapter 4 Wireless LAN 4. 1 Wireless LAN (WLAN) 4. 1. 1 Wireless LAN Linking of t