Microwave Oven Effects On Wireless Lans Essays - Wireless Networking

Microwave Oven Effects On Wireless Lans Microwave Oven Interference on Wireless LANs Operating in the 2.4 GHz ISM Band Abstract - Commercial microwave ovens as applied in restaurants have two magnetron tubes and compared to domestic kitchen counterparts they spread the higher RF power and radiated heating energy more evenly. The domestic kitchen or residential microwave ovens have only one magnetron tube. The interference from the commercial type of microwave ovens is more difficult to characterise than the interference from the residential ones. The commercial type of microwave ovens radiate a CW-like interference that sweeps over tens of MHz during the two bursts per mains power cycle. The residential ones give a CW-like interference that has a more or less stable frequency near 2.45 GHz occurring once per mains power cycle. The impact of the interference from the commercial type of microwave ovens on wireless LANs conforming the IEEE 802.11 standard for both DSSS (direct sequence spread spectrum) and FHSS (frequency hopping spread spectrum) has been evaluated. I. INTRODUCTION The release of the 2.4 GHz unlicensed band (2400 -2483.5 MHz) for ISM (industrial, scientific, medical applications) prompted a significant interest in the design of wireless LAN products. Interference from extraneous sources (unintentional radiators) impacts the reliability of communication in this 2.4 GHz ISM band. Sources of such interference are the millions of residential microwave ovens radiating at frequencies close to 2.45 GHz, and they have been described largely in the literature. Commercial microwave ovens, based on two magnetron tubes as used in restaurants, have been hardly described in the literature. Since commercial ovens are expected more often in the vicinity of office buildings with a high population density of office equipment and PCs, this type has been evaluated with respect to the nature of the interference signal and the impact on wireless LANs operating in the 2.4 GHz ISM band. At first, published material on residential microwave ovens, the reports from the NTIA (National Telecommunications and Information Administration, in the US) - [1] and [2] - are discussed. Next, the commercial microwave ovens and the nature of their interference is considered. The characterization of the interference from such ovens requires a dedicated measurement set up. Then the robustness of wireless LANs based on DSSS and FHSS conformant to IEEE 802.11 against CW interference is discussed. At last, the interference from the commercial microwave ovens on wireless LANs based on DSSS and FHSS is measured with a dedicated set up and the impact of the interference nature is considered. II. NTIA REPORTS The NTIA makes [1] and [2] some pessimistic conclusions about the possibility of sustaining highly-reliable communication links in this band. The ubiquitousness of these ovens and the wideband interference picture that emerges from peak-power measurements using, for example, conventional spectrum analysers in max-hold mode and multiple sweeps, has led to these pessimistic conclusions. The NTIA describes measurement results for residential microwave ovens with a maximum EIRP for these radiators that lies lay between +16 and +33 dBm. Some shortcomings in the NTIA measurement methods are presented in [3]. The NTIA reports give results of frequency- and time-domain measurements. Spectrum analysers in max-hold mode were used to measure in the frequency domain, which resulted in traces that capture the peak emission, at each frequency sampling point, occurring during the time interval of observation. Spectrum analysers in zero-span trace mode were used to find how the signal power around the selected frequency varies over time. [3] mentions that the NTIA peak spectrum measurements and frequency-domain characterisation with time-domain plots show a pulsed III. RESIDENTIAL MICROWAVE OVENS Microwave ovens have become more popular over the last fifteen years and can be found in over two hundred million home kitchens. The heating source of these residential microwave ovens is based on a single magnetron tube mostly positioned in an upper corner. Without further provisions, such an oven would produce an uneven heating effect, because of static stable standing wave patterns inside the cavity of the oven. Therefore, the usage of a rotating disk results in such a heating process at which the different sides of the rotated food or drink are ?illuminated? more evenly. The power consumption is mostly in the 600 - 800 Watt range. 2445 MHz 2452 MHz 2459 MHz 2466 MHz # RES BW 10 kHz # VBW 10 kHz # SWP 15.0 sec Peak 10 dB/div 2.41 GHz 2.48 GHz Frequency Fig. 1. Max-hold spectrum for residential microwave oven. # RES BW 3.0 MHz #VBW 1 MHz # SWP 30.0 msec Peak 10 dB/div fcentre 2.456 MHz Time 0 30 msec Fig. 2. Zero-span spectrum for residential microwave oven. NTIA measurement approach. With a high speed digital oscilloscope it can be shown, that during the active period the emitted signal is a CW with a frequency that moves over a few MHz. The beginning of the burst looks like a pulsed CW

Agoraphobia essays

Agoraphobia essays Grocery Store Disease Agoraphobia is a widely misunderstood disease. Agoraphobia has a couple of definitions because it is very complicated and difficult to understand. It is the fear of open spaces. It is also the fear of being in situation where a person can experience anxiety and begin to panic. People with agoraphobia may also have panic attacks if they are in a situation they consider to be difficult or embarrassing. Agoraphobia begins to develop when people start to avoid situations that are related to anxiety. People sometimes become housebound because they are always so nervous and paranoid and are scared to get out and possibly be stuck in a situation that they relate to anxiety. Some people with agoraphobia try to go out and have a normal life but it can be very difficult because they are so busy trying to hide their discomfort. Agoraphobia is an extremely severe anxiety condition that leads to avoidant behavior. Agoraphobia was commonly known as the Supermarket Disease before people began to learn more about it (Sharon Matt). The reasoning for that was because many women were having these unusual panic attacks in the middle of grocery stores. There are many typical situations where people have theses attacks. Shopping, driving, traveling, leaving town, and social gatherings are a few of the situations that bother those people with agoraphobia. They also fear large places like malls, theaters, parks, and grocery stores. Visiting the doctor and being on a bridge can make a person feel trapped (Sharon Matt). People with agoraphobia will worry that they will not be able to get to a place that they consider to be safe. Some people experience nervous feelings so regularly that it is more a feeling of discomfort rather than a feeling of panic. They fear going anywhere or doing anything where they have had panicky feelings before. They avoid these situations and places and they sometimes get depr e...

Business Case Study

A report on investigation into Business Case Date: May 02, 2013 Acquainted with your Business situation. I see a few problems within your business. One of the problems is changes in economic environment, which lead to conflict between stakeholders. The other problem is change of business structure. A success factor for any business is to analyse and understand the external environment in which it operates. Understanding of different types of stakeholders within business is essential too. To analyse business situation various method can be used. To analyse your current business situation I have used SWAT analyse which will give you opportunity better understand external environment and how it can impact your business. And will help you better understand conflict between stakeholders. The most basic SWOT analyse will examine how threats and opportunities can be dealt with while allowing the organisation to utilise its strengths and weaknesses to meet its key success factors [objectives]. A basic SWOT analysis should include an assessment of where the company is at current time and where it wishes to be at some point in the future . The organisation also needs to decide how far away that future is-it will vary from a few month to many years depending on the organisation, the nature of the business and its current situation (B 120, Book 1). SWOT analysis for the The Lodge Bistro Chain Strengths New IT system Initiative management stuff Possibility to adjust to changes Name and business recognition| Weaknesses Informal structure High stuff turnover Inconsistency in standards | | | | | | | | | | | | | | | Opportunities New consumers base Reinstate some formal structure and rules| Threats Complete loss of concept Lose of standards Competition External economic environment| | | | | | | | | | | | | | | | | As you can see from analyse above that the strengths will be recognition of your business and possibility of the business to adjust to new economic environment as you have initiative management team as it is described in Business Case: As an example of these issues, the young manager of one of the cafes in a central urban location began to offer a range of less expensive snacks to cater for diners on low incomes and reduced packaging to respond to the environmentally friendly principles of many customers. Another, in an area close to an office complex, offered a range of healthy eating options. It clearly shows that you have opportunities to attract new consumer’s base. Reinstate some formal structure and rules will give you better opportunity to control business Weaknesses arise from high stuff turnover, as you spend time, recourses for educating stuff. I think it would be beneficial to investigate why they leaving and looking for benefits packages you can purpose to your stuff And main threats arise from losing standards, huge competition and economic environment. For future I would purpose you to use methods like SWAT, STEEP and analyse of stakeholders before making any changes. Would be beneficial to make SWAT analyse on the way business was in 80’s and use it as comparison to current situation. It will give you opportunity to reinforce some formal structure more successfully. References The Open University (2006) B120 An Induction to business studies, Book 1, What is a business? ’, Milton Keynes, The Open University, page 95.

Students Own Experiences of Digital Technology and Implications for Research Proposal

Students Own Experiences of Digital Technology and Implications for the Design of University Education - Research Proposal Example In the last decade, higher education in Saudi Arabia has undergone a major transformation. There has been a three-fold increase in the number of universities in the last ten years. Consequentially, postgraduate students have increased in number. Along with this, improvement in the quality of education and making Saudi education come at par with the education of technologically advanced countries in terms of quality has been the major goal of Saudi universities in the 21st century. Several events have recently occurred that have reflected the increased interest of the students in Saudi Arabia in e-learning. In the year 2009, an international conference regarding cyberlearning and distance education was held in Saudi Arabia for the first time in her entire history. This led to the establishment of the Center for e-Learning and Distance Learning. This center was developed in accordance with the plan prepared by the Saudi Ministry of Higher Education that was directed at cultivating a ro bust infrastructure for the promotion of technology led education in the Universities of Saudi Arabia. Taking a look at the recent advancements that have been made in the field of education in Saudi Arabia, it becomes evident that this is a very crucial time for understanding how students’ own experiences of digital technology use in their personal lives influence their perceptions of ideal university education. Young people have conventionally been the primary users of innovation information technology (Rheingold, n.d. p. 97) â€Å"remaining at the top of Internet usage statistics and distinguishing themselves as early adopters of features such as instant messaging, peer-to-peer file sharing, and social networking tools† (Xenos and Foot, n.d.). Thus, the matter fundamentally concerns the youth and hence the future of Saudi nationals. This research will generate this information so that educationalists may be facilitated in adjusting the university education according to the aspirations of students which is conducive to the students’ increased participation and better academic performance. Provision of digital media in Saudi universities will â€Å"enhance their civic engagement, which comprises political activism, deliberation, problem-solving, and participation in shaping a culture† (Levine, n.d., p. 119).

Obtaining Civil Rights. How have African-Americans worked to end Essay

Obtaining Civil Rights. How have African-Americans worked to end segregation, discrimination, and isolation to attain equality and civil rights - Essay Example Establishment of slavery in America: The early 17th century marks the start of slavery in the US. During the era of 17th century humungous numbers of slaves were brought into US from different areas of Africa. The life expectancy rate during that time period in the Brazilian regions was quite low so these slaves were brought to US where the level of life expectancy was better. Many historians claim that nearly 6 million highly competent slaves were brought from abroad especially from Africa to America in the 18th century (Griffin, 2009, 605). During the 18th century, most of the black slaves worked on the tobacco and rice plants, located near the southern coast. Many colonists claim that after the American Revolution, the black slaves in America were overpowered by the British in order to abolish slavery in the nation because they expected that this would end up in resulting in adverse effects. However, as the war ended, the new American constitution counted every slave in the country as three-fifths of a person with the intention of taxation and ensuring the right to seize ‘any person who is acquired for labor or other services’. Role of cotton gin: The number of slaves in America began to reduce in the late 18th century due to shortage of lands required for growth of tobacco. Due to this terrible exhaustion of tobacco plants, an economic crisis hit the South. During this period, textile industries were rapidly growing in the Britain and the demand for cotton reached its zenith. The textile industries in the Britain demanded the American cotton for speedy growth of these industries. Unfortunately, growth of American cotton was restricted in America due to difficulty of elimination of seeds from raw fibers of cotton by hand. This problem was sorted out in 1700s by a young school teacher, Eli Whitney, who invented a machine known as cotton gin for easy removal of seeds (Griffin, 2009, 598). This device brought a revolution not only in America, but in South Asia too as a rapid transition from production of tobacco to production of cotton was witnessed. A great number of businessmen benefitted by investing on cotton plants and this investment aided them in earning high levels of wealth. Almost all northern states put an end to slavery between the years 1700s to 1800s and the US Congress excluded the African slave trade from the benefit of the law, but these actions never really affected the growth of slaves in America. The population of slaves in the United States of America grew so rapidly that it had tripled over the next 45 years. By the year 1860, the population of slaves rose to 5,97,000 individuals, with most of the slaves dwelling in the cotton-producing southern states. Brutal behavior of slaveholders and the slave revolts: One-third of the southern population comprised of slaves in the Antebellum South. A good number of these slaves subsisted on either huge farms or plantations with most of the masters owning only less than 50 slaves. A strict method of restrictive codes regulated the lives of these slaves as the slave owners wanted the slaves to be entirely dependent upon their masters. The slaves we re strictly interdicted by their masters from educating themselves. The behavior as well as the movement of the slaves were also governed by the slave owners and were restricted. Slave owners took sexual privileges with slave

THE IMPACT OF MONETARY POLICY ON NIGERIAS ECONOMIC DEVELOPMENT Essay Example for Free

THE IMPACT OF MONETARY POLICY ON NIGERIAS ECONOMIC DEVELOPMENT Essay Monetary policy being an economic tool is used to stabilize the economy. It is a tool used by the government through monetary agencies like the Central Bank to control the supply of money in an economy. It is used to bring about economic growth and development through the control of inflation. It impacts the economy cannot over-emphasized. It has very positive impacts on the economy and helps in building a sustainable economy. Monetary policy is the process by which the monetary authority of a country controls the supply of money, often targeting a rate of interest for the purpose of promoting economic growth and stability. It is maintained through actions such as increasing the interest rate, or changing the amount of money banks has to keep in the vault(bank reserves). It can be used to increase or decrease the volume of money in circulation based on the situation at hand. PURPOSE OF THE STUDY The intent of the proposed study is to critically examine the impact of monetary policies on the Nigerian economy. The focus will be on how monetary policies adopted in recent years have impacted on the Nigerian economy. How the federal government have strived through the use of monetary policies to stabilize and develop the Nigerian economy. The intent is to provide adequate information to readers on the roles played by monetary authorities and monetary policies in ensuring economic growth and development in the entity called Nigeria. An objective approach shall be employed in order to bring about valid arguments and conclusions. LITERATURE REVIEW Scholars in the economic and financial field have written articles on the proposed research topic. Professor Kunle Adamson in 2002 wrote an article in this regard.he placed emphasis on the then proposed re-denomination of the naira by the then CBN governor Professor Charles Soludo. He critically analysed how the re-denomination of the naira would have impacted the Nigerian economy. Another literature to be reviewed is the article written by Dr Okoro A. Sunday(Ph.D) of the Ebonyi State University. He critically examined the long-run equilibrium relationship between monetary policy instruments and economic growth in Nigeria. The intent  of the proposed research is to explore the various angles to the research topic. The poor implantation process would also be critically examined.

Communist Controversy over Film Salt of the Earth Essay -- Politics Mc

Communist Controversy over Film Salt of the Earth Salt of the Earth was released in 1954, during the anticommunist McCarthy era by a collection of blacklisted individuals, including screenwriter Michael Wilson, producer Paul Jarrico, and Hollywood 10 director Herbert J. Biberman. Salt is based on the Empire Zinc strike of Local 890 in Bayard County, New Mexico that took place from 1950-1952. In many ways, Salt of the Earth resembles the archetypal American dream by presenting the triumph of ordinary, working class Americans over the forces of discrimination, inequality, and injustice. Salt enjoyed widespread acclaim in Europe, and won prestigious awards in Czechoslovakia and France. Yet in the United States, its production encountered violent opposition from agencies such as the Screen Actors Guild, the American Federation of Labor and the Federal Bureau of Investigation. What particular element of Salt made it seem so threatening and subversive? According to film critic Pauline Kael Salt was nothing more than "shrewd propaganda for the urgent business of the USSR." (Kael, 331-332) She unhesitatingly asserts that Salt is "as clear a piece of communist propaganda as we have had in many years" (Kael 331-332). In short, Kael argues that Salt is fundamentally subversive, threatening and un-American. Yet what does it mean to be subversive in the context of the McCarthy era? The Oxford English Dictionary defines the noun subversive as wishing to "overthrow a regime" (OED). Kael’s argument seems to be congruous to this definition. Does Salt of the Earth intend to overthrow the existing political order and replace it with a communist form of government? Several scholars have responded to Kael’s communist reading of Salt. Lorence... ...d English Dictionary. Accessed 2. June.2003 9. Rosseau, Jean-Jacques. The Social Contract. Liberty, Equality, Fraternity: Exploring the French Revolution. Hunt, Lynn & Censer, Jack. University Park, Pennsylvania: The Pennsylvania State University Press (2001) 10. Rosenfelt, Deborah S. Salt of the Earth: commentary by Deborah Silverton Rosenfelt and Screenplay by Michael Wilson New York: The Feminist Press, (1978) 11. Salt of the Earth. Dir. Herbert J. Bibberman. Produced by Paul Jarrico. Screenplay by Michael Wilson. Video recording. Independent Productions Corporation and the International Union of Mine. (1954) 12. Wilson, Michael. Salt of the Earth: commentary by Deborah Silverton Rosenfelt and Screenplay by Michael Wilson. (The Screenplay) New York: The Feminist Press, (1978)