Open System Interconnection (OSI) Essay Example | Topics and Well Written Essays - 1250 words

Open System Interconnection (OSI) - Essay Example The data transport or 'lower layers' of the OSI model handle data transport issues and are implemented in hardware and software. The lowest layer, the physical layer, is responsible for actually placing information on the medium. As a side note, most systems today use a modified version of this model; for example TCP/IP uses a 6-layer model. The OSI model is generic and is not a communication model -it makes no assumptions about programming language bindings, operating system bindings or application and user interface issues. Communications are implemented through protocols which are a formal set of rules and conventions that govern how computers exchange information over a network medium. A protocol implements the functions of one or more of the OSI layers. The table below describes the role of each of the 7 layers in greater detail: Responsible for activating, maintaining and deactivating the physical link between network objects. Network interface cards and interfaces on routers run at this level. Physical layer specifications define characteristics such as voltage levels, timing of voltage changes, physical data rates, maximum transmission distances, and physical connectors. Physical layer implementations can be categorized as either LAN or WAN specifications. When an application on Computer 1 sends dat... Provides error checking, error recovery and flow control. The transport protocols used on the Internet are TCP and UDP. 3 Network Layer Makes the upper layers independent of the data transmission, switching technologies, and topology of the network. Determines which path(s) in the network that data will be routed. This layer is very important to the design and configuration for internetworking. IP and routing protocols operate here. 2 Data Link Layer Provides reliable transfer across the physical links. Establishes the beginning and end of blocks of data (with synchronization when necessary) Reorder frames which are out of sequence [framing]; error detection and correction rate of data transmission [flow control]. It is subdivided into the logical Link Control (LLC) and Media Access Control (MAC) sub layers. Bridges and switches interface here. 1 Physical Layer Responsible for activating, maintaining and deactivating the physical link between network objects. Network interface cards and interfaces on routers run at this level. Physical layer specifications define characteristics such as voltage levels, timing of voltage changes, physical data rates, maximum transmission distances, and physical connectors. Physical layer implementations can be categorized as either LAN or WAN specifications. electrical optical mechanical When an application on Computer 1 sends data to Computer 2 that data passes through each layer of the OSI model on Computer 1 until it gets to the Physical layer. At that point it is transmitted on the physical medium (e.g. cabling) across to the Physical layer on Computer 2. The data then passes up through the Physical, Data, Network, Transport, Session, Presentation and

The Zachman Framework Essay Example | Topics and Well Written Essays - 1500 words

The Zachman Framework - Essay Example Despite numerous achievements, many information systems leave sufficient room for improvement. Less than a decade ago, John A. Zachman (1996) wrote that information technologies and systems in most of Fortune 500 enterprises were in the state of deep frustration. Today’s information technologies are much better than those in the middle of the 1990s, but there are no limits to excellence. The Zachman framework exemplifies a successful attempt to revolutionize enterprise architecture principles and solve the centuries old problem of inefficient enterprise architecture, which hinders the development of relevant business frameworks. The beginning of the 1980s was marked with the rapid advancement of information technologies and systems. However, it was not before the end of the 1980s-the beginning of the 1990s that enterprise engineering ideas became popular and relevant. Throughout of the 1980s, most enterprise modeling ideas were limited to simplified application development, with no attention given to the concept of architecture and its implications for information systems evolution (Zachman, 1993). The lack of attention to enterprise architecture and reengineering precipitated the development of the Zachman framework. In today’s information systems practice, the Zachman framework is believed to be the most comprehensive and practical of all enterprise architecture systems known to the public (Urbaczewski & Mrdalj, 2006). The Zachman framework represents a logical structure that helps to clarify, classify, and organize the main descriptive representations of enterprise architecture (Zachman, 1993). ... The Zachman framework represents a logical structure that helps to clarify, classify, and organize the main descriptive representations of enterprise architecture (Zachman, 1993). The Zachman framework â€Å"comprises descriptive representations that are essential to successful management of enterprises and future development of information systems† (Zachman, 1993). The framework is built on previous models of architecture and engineering, used to organize processes and decisions in complex manufacturing processes (Zachman, 1993). The main goal of the framework is to simplify and facilitate the development of complex enterprise architecture solutions (Zachman, 1993). The Zachman framework is a bi-dimensional scheme of classifying all descriptive representations of any enterprise (Frankel et al, 2003). The framework comprises one vertical and one horizontal dimension; the former describes all perspectives of those who use the descriptions and models in the cells, whereas the la tter helps to answer â€Å"the basic questions of enterprise architecture – what, how, where, who, when, and why† (Frankel et al, 2003). Models represented in the Zachman framework include (from the top to the bottom) â€Å"scope, business model, system model, technology model, detailed representations, and the functioning enterprise† (Frankel et al, 2003). The scope sets the boundaries of enterprise architecture and creates a general picture of enterprise architecture to be considered by managers (Frankel et al, 2003). The business model incorporates all types of architectures and frameworks used by corporate owners (Frankel et al, 2003). The system model is devoted to architectures and systems used by architects and engineers,

Policy Change Essay Example | Topics and Well Written Essays - 1000 words

Policy Change - Essay Example Thus, this essay will argue that ideas affect policy change only indirectly, as paradigms frames and determinants of interest, such that its importance in understanding policy change is only secondary to other approaches. To better understand the importance of a study of ideas in policy change, it is first necessary to understand what ideas are. Ideas are shared beliefs held by individuals. However, a distinction must be made between two categories of shared beliefs, particularly "consensual beliefs" and "economic ideas", where although not mutually exclusive differ in their relation to policy. As Jacobsen explains, the difference lies between those of "means" to "ends", where consensual beliefs "shape the legitimate ends of economic activity"; economic ideas are the means to reach these ends. 3 Taking this definition of ideas, the importance of a study of ideas in policy change can be summarised in their roles as paradigms, roadmaps, or ideational frames. Comparing policy change to scientific revolutions, Hall (1989) places emphasis on the role of ideas through "policy paradigms", or "roadmaps" as Goldstein and Keohane (1993) calls them, where ideas guide policies by determining the "tracks" of policymaking and setting constraints in the policy process4. As Hall argues, policy paradigms, determine policy change in acting as "a framework that specifies the goals of policy and the kind of instruments that can be used to attain them", as well as the "nature of the problems they are meant to be addressing."5 Campbell's (1998) and Beland's (2005) ideational frames or programmes also echoes Hall's concept of paradigms, varying only in the manner that ideas are presented and implemented in the policy process. Within this strand of literature, the failures of policies to achieve economic goals are seen as the impetus for policymakers to search for alternative ideas that pave the way for new policy paradigms to be accepted. Hence, in times of uncertainty marked with "exogenous shocks, demographic changes [or] the perception of failed policy", new ideas emerge as either roadmaps or focal points that reduce uncertainty and provide alternatives.6 The policy shift during the first Thatcher government can therefore be explained as the result of a shift in policy paradigms; replacing Keynesian ideas with monetarist ideas (Hall, 1993). Looking at the first Thatcher government, it is evident that the policy shift coincided with an ideational shift from Keynesian to monetarist where Keynesian policies were perceived to have failed in resolving rising inflation (Walsh, 2000). In this respect,

Strategic management Essay Example | Topics and Well Written Essays - 3500 words - 3

Strategic management - Essay Example outstanding business performance on the part of the company considering that Cathay Pacific earned only HK$812 million during the first and second quarter of 2009 (ibid). It is a common knowledge that the economic and financial performance of each country could somehow significantly affect the supply and demand for airline services. Basically, economic recession associated with stock market crashes, currency crises, real estate crises, and financial bubbles among the long list of other financial and banking problems such as the case of the Lehman Brothers could adversely affect the business performance of airline companies. In some cases, the rise and fall of oil prices in the world market, the presences of SARS outbreak, and the post September 11-crises could also affect the profitability of airline companies. Considering the past and present global economic crisis and the actual business performance of Cathay Pacific in the global markets, this study aims to identify and discuss the prevailing strategies used by the company to enable the business remain strong despite the challenges faced by the airline companies. Basically, analyzing the strategies used by Cathay Pacific will enable the readers to have a better understanding behind the secret of the company’s successful endeavour. Today, Cathay Pacific is considered as one of the best and most competitive â€Å"Asian Airline Business† within the global airline industry. As part of determining the competitive advantages of Cathay Pacific against its close competitors like the Singapore Airlines Limited, major factors that made the company successful in implementing its business strategies will be mentioned and critically analyzed. In line with going through the main discussion, the company’s superiorities and inferiorities could significantly affect the decision-making process of its top management will be tackled in details. Airways, the company managed to effectively surpass the declining demand for

The effectiveness of Polymer reinforced Concrete Masonry (CMU) Walls Essay

The effectiveness of Polymer reinforced Concrete Masonry (CMU) Walls as Compared to unreinforced CMU Walls - Essay Example Using of FRP composites have been viewed as a suitable and cost-effective way for strengthening URM. Seismic design in the USA is nearly completely grounded on the consideration that the structural system gives a flexible failure mode. Masonry walls strengthened by FRP actually have fragile failure modes as a result of the nature of the strengthening system itself. The idea explored in our research paper is the introduction of flexibility using some kind of hybrid strengthening system. We based our investigation on the experiments held by J.J. Myers and P. Carney (cited in Tumialan, 2005). The research study investigated the practicability of developing continuity between the FRP and the surrounding reinforced concrete frame system. In the paper, we evaluated strengthened URM wall's functioning using static tests as tools for our investigation. The authors whose works we used for the examination utilized 2 strengthening methods including the application of glass FRP (GFRP) laminates to the wall's surface and the installation of near surface mounted (NSM) GFRP rods. In both methods, the strengthening material was anchored to boundary members above and below the wall on some of the specimens in the research program. A shear retrofit, the effects of bond pattern, and the effects of FRP laminate strip width were also investigated in our paper. The development of continuity between the FRP materials and the surrounding framing system is important to improving the blast resistance of URM infill walls. Keywords: FRP strengthening; blast resistance; masonry wall retrofits; masonry wall connections. 1. INTRODUCTION 1.1. BACKGROUND Recent events in the world have attracted attention to the vulnerability and sustainability of buildings and infrastructure to acts of terrorism. Our infrastructure is vital to this nation's economy and way of life. Any damage to it would and has had drastic effects on our culture. Attacks may cause a variety of results ranging from minor building damage to complete structural failure and considerable loss of life. Some examples within the United States include the bombing of the Murrah Federal Building in Oklahoma City (1995) and the bombing and attacks on the World Trade Center in New York City (1993, 2001). Abroad, numerous attacks have been directed toward embassies, and suicide car bombers have been used to targetpopulated areas. In the cases where complete structural failure is not an issue, the dangers of flying debris have resulted in loss of life or injury to numerous civilians. Of particular concern are unreinforced masonry (URM) infill walls. Structural sys tems composed of a reinforced concrete (RC) framing system with URM infill walls makes up a significant portion of the building inventory in the United States and around the world. Since there is no reinforcement within these walls, they have little resistance to out-of-plane loads such as a blast load. As a result, an effort has been undertaken to examine retrofit methods that are feasible to enhance their out-of-plane resistance. One method of strengthening URM walls is the application of fiber reinforced polymers (FRP) to the surface of the wall to improve their performance. Today, FRP is considered an emerging technology. Its use began becoming

Quantitative Analysis for Finance Coursework Example | Topics and Well Written Essays - 2000 words

Quantitative Analysis for Finance - Coursework Example Basing on the calculated percentages, the return of each portfolio was calculated. Therefore, based on the results, the plan consists of the losses and the highest drawdown which could help investors prepare for what they could face in future. In relation to this, even if the financial plan is considered to be the simplest, it needs assumptions about the way the investment could perform. It is known that such assumptions might not be accurate, but they are required to be reasonable as well as thoughtful. The projections won’t be that useful in case you assume a balanced portfolio with a return of 7 percent every day. It was found that the returns of the total portfolio of investors during the year are negative and this indicates that the portfolio is not good enough to invest. Such resulted from the drop in value of the initial investment of the common bond which was from 30 000 pounds to 23 000 pounds. There was rise in value of the stock investment from 20 000 pounds to 25 0 00 pounds and this implies that the stock portfolio is good for investment. In regard to the determination of the capital market line equation (CML), we considered the fact that there was a correlation coefficient between the stock returns of 30 percent and the risk free rate of 5 percent .The risk profile could be altered easily when the asset risk is adjusted with the use of the risk –free rate. Based on the capital market line, the market portfolio has a combination of all risky-free asset and risky assets, with the use of the asset‘s market value to calculate the weights. The capital market line was derived by capital market model (CAPM) where the expected return at different risk levels was solved. For exercise 2, the capital market line was determined and in this case, it indicated that the diversified portfolio returns on the capital

Ethical issue at Starbucks Research Paper Example | Topics and Well Written Essays - 1250 words

Ethical issue at Starbucks - Research Paper Example However, recent discoveries show an otherwise picture (Cross et al 2009). According to Rhetoric Society of America et al (2004), Starbucks has been covering up many things such as serving milk with GM growth hormone in US. Besides, it has been running relentless campaigns of bursting unions. According to Schultz et al (2011), the company is also accused of attempting to block the attempts of Ethiopia to improve the coffee grower’s livelihoods. Furthermore, it has also petitioned a federal judge to accept in past sexual history evidence of a former employee aged 16 years when she took sexual harassment case to court. Despite the fact that the company has sold as standard Fair-trade Coffee since 2009 in all its stores in UK, the rest of the operation globally on the uptake has been slower. The firm has been criticized even for its operations in US by Organic Consumers Association also dragging its feet in Fair-trade launch (Michelli 2007). In addition, Gilbert (2008) points out the order by the US court on Starbucks to pay low wage staff more than $100million in California in a ruling that the workers improperly shared with their bosses some tips although was overturned subsequently after a successful appeal. The lawsuit against Starbucks was for using tactics that are anti competitive to eliminate their competitors. The employees of Starbucks would give out their coffee rights as free sample outside the small shops of coffee in their neighborhoods, thereby gaining more profit and business for themselves. Furthermore, Bussing-Burks (2009) add that they sometimes even tried to buyout other shops of coffee near them. They would sometime sign leases for almost 3 times of the market price to make the landlords not rent it out to other sellers of coffee. Marie et al (2009) adds that Howard Schultz the chief executive officer earned a pay rise of 25% after a cost of $580 million slashed from the company in the year 2009. By analyzing the actions of Starbucks, it is unethical because the stores of small coffee give much to the people in the towns they are located compared to what Starbucks does. Majority of people love small coffee shops with reasonable coffee prices in their surrounding towns. On the other hand other people would be contented with Starbucks. However, Kachra (1997) explains that although you might love Starbucks, you would not like a coffee shop that has been in existence in your town for long being faced out of business. According to Schultz et al (2007) the small coffee shops found in most towns gives happiness to more people unlike Starbucks which overcharge their coffee. It is very unethical for a firm like Starbucks to overprice their products since they know they are alone in the market after displacing other businesses therefore people will lack other options. Moreover, they disregarded other small business by being selfish and negatively facing them off gaining all the clients and profits. Fellner (2008) observes th at the company did not value people but considered them as sources of profits. Their technique of expansion does not have goodwill and they are also not motivated rightfully. Simon (2009) observes that the company does not also comply with their set legislations. This is because Starbucks motto clearly elaborates they will treat their clients dignity and respect. However, no dignity or respect is shown to their clients or even the communities. According to Olsen (1994), Starbucks