Background & The Evolution of the Internet

The Internet has undergone explosive growth since the first connections were established in 1969. This growth has necessitated an extremely large system scale-up that has required new developments in the technology of information transfer. These new developments allow simplified solutions to the problem of how to reliably get information from point A to point B. Unfortunately, the rapid pace of the required technological advancement has not allowed for optimal solutions to the scale-up problem.Rather, these solutions appear to have been the most convenient and practical at the time. Thus, the information transfer technology of today’s internet does not guarantee the ‘best path’ for data transmission. The definition of the best path may mean the most cost effective or the fastest path or some path based on optimization of multiple protocols, but the current technology used in the internet cannot guarantee that the best path for data transmission will be chosen. The result is a reduction in economic and system resource efficiency. The Evolution of the InternetThe Internet has become integrated into the economic, technological and security infrastructure of virtually every country in the world. However, the internet had quite a humble beginning. It was originally designed as a back-up military communications network (MILNET) and as a university research communications network (National Science Foundation Network, NFSNET / Advanced Research Projects Agency Network, ARPANET). The original technology developed for these limited systems was not designed for the massive scale-up that has occurred since inception.Moreover, the original design of the internet system was based on the sharing of resources. The recent applications of the internet for commerce and proprietary information transfer processes make resource sharing an undesirable aspect. A more recent development is resource usage based on policies limiting what part of the internet can use a specific service or data transmission line. An Introduction to Networks and Routing What is a network? A network is a group of computers linked together by transmission lines that allow communication between the computers.Some of these computers are the equipment used by people on their desktop. Other computers in the network are computers that are designed only to direct traffic on the network or between different networks. Computer scientists often think of networks as large graphs with lines used to connect dots. The dots are called nodes and correspond to computers and the lines correspond to the transmission lines that connect the computers. The Internet is a giant network of smaller networks, called autonomous systems, that allows computers to be connected around the globe.What is routing? The process of transmitting information from a source computer to a destination computer is called routing. The way this is done can greatly effect how quickly the information is transmitte d between the two computers. What is a router? A router is a computer with more than one connection to the rest of the network that is programmed to choose which transmission lines to send information. Some routers or designed to route information between networks, as on the Internet, while other routers work to route information between computers on the same network.How do routers route? In order for routers to choose the best route (or path) from the source computer to the destination computer, it is necessary that the routers communicate with each other about what computers and networks they are connected to and the routes that can be used to reach these computers and networks. Often these routes must go through other routers. What are advertisements? Advertisements are the messages sent between routers to communicate information about routes to reach each destination. What is convergence?Convergence occurs on the network or internet when all the routers know all the routes to al l the destinations. The time required for all the routers to agree on the state of the network, the network topology, is known as the convergence time. When convergence does not occur, then data can be transmitted to a router which does not know how to get to a destination and this data is then lost. This is called a black hole. It is also possible that the data can be passed around a set of routers continuously without getting to the destination. This is called a routing loop. What is a data packet?When a large message is being transmitted, the message will probably be broken up into smaller messages called data packets, and these data packets may not all be sent by the same path across the Internet, although they will hopefully all reach the same destination What is a metric? A routing metric is a measure associated with a particular path between a source and a destination used by the router to decide what path is the best path. Typical metrics used by routing algorithms include p ath length, bandwidth, load, reliability, delay (or latency) and communication cost.Path length is a geometric measure of how long the transmission lines are. Bandwidth is used to describe the available transmission rate (bps) of a given section the possible transmission path. The load is the data packet transmission per unit time. The reliability of a data transmission path is essentially the number of errors per unit time. The delay in data transmission along a certain path is due to a combination of the metrics that have already been discussed, including geometric length of the transmission lines, bandwidth, and data traffic congestion.The communication cost is essentially the commercial cost of data transmission along a certain transmission line. What is a router protocol? A router protocol is the way the router is programmed to choose the best path for data transmission and communicate with other routers. This algorithm will consider path metrics associated with each path in a way defined by the by the manager of each AS. What is an internet address? In order for routers to identify the destination of a data transmission, every destination must have an address.The internet protocol (IP) method of addressing destinations uses a series of digits separated by dots. An example of an Internet address is 227. 130. 107. 5. Each of the 4 numbers separated by a dot has a value between 0 and 255. This range of values is set from the amount of computer memory designated for addressing at the beginning of the internet. The internet addressing scheme is similar to a scheme for international telephone calls. There is a ‘country code’ which is a fixed number for each country, and then there are other numbers which change on the phone number to refer to specific locations within the country.The numbers on the IP address for a network on the internet correspond to what would be the country code on an international phone number are referred to as ‘prefix ’. The other numbers on the IP address change to refer to individual computers on that particular network. A ‘netmask’ can also be used to specify which numbers on the IP address for a given network are fixed and which ones can be changed. A netmask is a series on ones and zeroes that can be put over the IP address. The part of the IP address under the ones is fixed as a network address.The part of the IP address under the zeros can be changed to indicate specific computers on the network. What is a Domain Name System (DNS), the domain name and the Uniform Resource Locator (URL)? The DNS is a combination of computer hardware and software that can rapidly match the text specification of an IP address, like www. helpmegetoutofthis. com, to an IP address. The part, helpmegetoutofthis. com, is called the domain name. The whole text, www. helpmegetoutofthis. com, is called the Uniform Resource Locator (URL).When you send an e-mail or use the Internet, you use the doma in name and the URL to locate specific sites. This allows people to type in the text name, or domain name, of an internet site into the Netscape browser instead of trying to remember the numerical IP address. The DNS automatically matches the text name to the IP address for the user when the transmission request is submitted. What are servers and clients? All of the computers on the Internet are classified as either servers or clients. The computers that provide services to other computers are called servers.The computers that connect to servers to use the services are called clients. Examples of servers are Web servers, e-mail servers, DNS servers and FTP servers. The computers used at the desktop are generally clients. How the internet works. Although the details of routing and software are complex, the operation of the internet from the users’ perspective is fairly straight forward. As an example of what happens when the Internet is used, consider that you type the URL www . helpmegetoutofthis. com into the Netscape browser.The browser contacts a DNS server to get the IP address. A DNS server would start its search for an IP address. If it finds the IP address for the site, then it returns the IP address to the browser, which then contacts the server for www. helpmegetoutofthis. com, which then transmits the web page to your computer and browser so you can view it. The user is not aware that of the operation of an infrastructure of routers and transmission lines behind this action of retrieving a web page and transmitting the data from one computer to another.The infrastructure of the internet can be seen as a massive array of data relay nodes (routers) interconnected by data transmission lines, where each node can service multiple transmission lines. In the general case where information must be sent across several nodes before being received, there will be many possible pathways over which this transmission might occur. The routers serve to find a p ath for the data transmission to occur. The routing of a file or data packets of a file is either be done by the technique of source routing or the technique of destination routing.In source routing, the path the data transmission will follow id specified at the source of the transmission, while destination routing is controlled by the routers along the path. In the modern internet, almost all routing is done by destination routing because of security issues associated with source routing. Thus, the routers must be programmed with protocols that allow a reasonable, perhaps optimum, path choice for each data packet. For the routers to choose an optimum path also requires that the interconnected routers communicate information concerning local transmission line metrics.Router communication is thus itself a massive information transfer process, given that there is more than 100,000 networks and millions of hosts on the Internet. When viewing the enormity of the problem, it is perhaps e asier to understand why engineers have accepted a sub-optimal solution to the problem of efficiency in data transfer on the Internet. When initially confronting a problem, the practical engineering approach is to simplify the problem to the point where a working solution can be obtained and then refine that solution once the system is functional.Some of the simplifying assumptions used by engineers for the current internet data transmission system include 1) A transmission line is never over capacity and is always available as a path choice. 2) The performance of the router and transmission line does not depend on the amount of traffic. These two assumptions do simplify the problem of path choice considerably because now all the transmission lines and nodes may be considered equal in capacity and performance completely independent of traffic. As such, it is a much simpler optimization problem consisting of finding the route with the shortest path length.To simplify the problem even further, another assumption is made: 3) Consider that an â€Å"Autonomous System† (AS), is a small internet inside the Internet. An AS is generally considered to be a sub-network of an Internet with a common administrative authority and is regulated by a specific set of administrative guidelines. It is assumed that every AS is the same and provides the same performance. The problem of Internet routing can now be broken down into the simpler problem of selecting optimum paths inside the AS and then considering the optimum paths between the AS.Since there are ‘only’ around 15,000 active AS’s on the Internet, the overall problem is reduced to finding the best route over 15,000 AS nodes, and then the much simpler problem of finding the best route through each AS. There is an important (to this thesis) set of protocols which control the exchange of routing information between the AS’s. The sort of routers in an AS which communicates with the rest of the internet and other AS’s are called border routers. Border routers are controlled by a set of programming instructions known as Border Gateway Protocol, BGP.A more detailed discussion of computer networking principals and the Internet facts can be found in e. g. [7]. An Introduction to Router Protocols. Routers are computers connected to multiple networks and programmed to control the data transmission between the networks. Usually, there are multiple paths that are possible for transmission of data between two points on the Internet. The routers involved in the transmission between two points can be programmed to choose the ‘best path’ based on some metric. The ‘protocols’ used to determine the path for data transmission are routing algorithms.Typical metrics used by routing algorithms include path length, bandwidth, load, reliability, delay (or latency) and communication cost. Path length. Path length is a geometric measure of how long the transmiss ion lines are. The routers can be programmed to assign weights to each transmission line proportional to the length of the line or each network node. The path length is then the sum of the weights of the nodes, lines or lines plus nodes along the possible transmission path. Bandwidth. Bandwidth is used to describe the available transmission rate (bps) of a given section the possible transmission path.An open 64 kbps line would not generally be chosen as the pathway for data transmission if an open 10 Mbps Ethernet link is also open, assuming everything else is equal. However, sometimes the higher bandwidth path is very busy and the time required for transmission on a busy, high bandwidth line is actually longer than on a path with a lower bandwidth. Load. This data packet transmission per unit time or the percent of CPU utilization of a router on a given path is referred to as the load on this path. Reliability.The reliability of a data transmission path can be quantitatively descri bed as the bit error rate and results in the assignment of numeric reliability metrics for the possible data transmission pathways. Delay. The delay in data transmission along a certain path is due to a combination of the metrics that have already been discussed, including geometric length of the transmission lines, bandwidth, and data traffic congestion. Because of the hybrid nature of the communications delay metric, it is commonly used in routing algorithms. Communication Cost.In some cases, the commercial cost of data transmission may be more important the time cost. Commercial organisations often prefer to transmit data over low capacity lines which they own as opposed to using public, high capacity lines that have usage charges. The routing algorithms do not have to use just one metric to determine the optimum route; rather it is possible to choose the optimum route based on multiple metrics. In order for the optimum path to be chosen by the routers between the data source and the data destination, the routers must communicate information about the relevant metrics with other routers.This nature of this communication process is also defined by the routing algorithm and the transmission time is linked to the time required for the routers to have the necessary information about the states of the surrounding routers. The time required for all the routers to agree on the state of the network, the network topology, is known as the convergence time and when all routers are aware of the network topology, the network is said to have converged. Some of the common routing algorithm types can indeed affect the convergence of the network.Some of the different algorithms characteristics that must be chosen when designing are static or dynamic routing, single path or multi-path routing and link state or distance vector routing. Static Routing. Static routing is done by use of a static list of attributes describing the network topology at the initiation of the network. This list, called a routing table, is used by the routers to decide the optimum routes for each type of data transmission and can only be changed manually. Therefore, if anything changes in the network, such as a cable breaking or a router crashing, the viability of the network is likely to be compromised.The advantage is that there is no communication required between routers, thus the network is always converged. Dynamic Routing. In contrast to static routing, dynamic routing continually updates the routing tables according to changes that might occur in the network topology. This type of real time information processing allows the network to adjust to variations in data traffic and component reliability, but does require communication between the routers and thus there is a convergence time cost associated with this solution.Single Path vs Multi-path Routing. Single path and muli-path routing are accurate descriptive terms regarding the use of either a single line to send multip le packets of data from a given source to a given destination as opposed to using multiple paths to send all the data packets from the source to the destination. Multiple path algorithms achieve a much higher transmission rate because of a more efficient utilization of available resources. Link State vs Dynamic Routing Protocols.Link-state algorithms are dynamic routing algorithms which require routers to send routing table information to all the routers in the network, but only that information which describes its own operational state. Distance-vector algorithms, however, require each router to send the whole of its router table, but only to the neighbouring routers. Because the link-state algorithms require small amounts of information to be sent to a large number of routers and the distance vector algorithm requires large amounts of information sent to a small number of routers, the link state algorithm will converge faster.However, link state algorithms require more system reso urces (CPU time and memory). There is a new type of algorithm developed by CISCO which is a hybrid of the link-state algorithm and the distance vector algorithm [8].. This proprietary algorithm converges faster than the typical distance-vector algorithm but provides more information to the routers than the typical link-state algorithm. This is because the routers are allowed to actively query one another to obtain the necessary information missing from the partial tables communicated by the link-state algorithms.At the same time, this hybrid algorithm avoids communication of any superfluous information exhibited in the router communications of the full tables associated with distance-vector algorithm. Switching. The distance vector, link state or hybrid algorithms all have the same purpose, to insure that all of the routers have an updated table that gives information on all the data transmission paths to a specific destination. Each of these protocols requires that when data is tra nsmitted from a source to a destination, the routers have the ability to ‘switch’ the address on the data transmission.When a router receives a data packet from a source with the destination address, it examines the address of the destination. If the router has a path to that destination in the routing table, then the router determines the address of the next router the data packet will ‘hop’ to and changes the physical address of packet to that of the next hop, and then transmits the packet. This process of physical address change is called ‘switching’. It will be repeated at each hop until the packet reaches the final destination.Although the physical address for the forwarding transmission of the data packet changes as the packet moves across the Internet, the final destination address remains associated with the packet and is a constant. The internet is divided up into hierarchical groups that are useful in the description of the switching process. At the bottom of this hierarchy are network devices without the capability to switch and forward packets between sub-networks, where an AS is a sub-network.These network devices are called end systems (ESs), because if a packet is transmitted there, it cannot be forwarded and has come to the end. At the top of the hierarchy are the network devices that can switch physical addresses are called intermediate systems (ISs). An IS which can only forward packets within a sub-network are referred to as intra-domain ISs while those which communicate either within or between sub-networks are called intra-domain ISs. Details of Routing Algorithms Link State AlgorithmsIn a link state algorithm, every router in the network is notified of a topology change at the same time. This avoids some of the problems associated with the nearest neighbour update propagation that occurs in the distance vector algorithms. The ‘Open Shortest Path First’ (OSPF) protocol uses a graph topolo gy algorithm like Dijkstra’s Algorithm to determine the best path for data transmission between a given data source and a data destination. The metric used for route optimisation is specific to the manual configuration of the router.However, the default metric is the speed of the interface. The OSPF uses a two level, hierarchical network classification. The lower level of hierarchy is groups of routers called areas. All the routers in an area have full knowledge of all the other routers in the area, but reduced knowledge of routers in a different area. The different areas organized within the OSPF algorithm are connected by border routers, which have full knowledge of multiple areas. The upper level of the hierarchy is the backbone network, to which all areas must be connected.That is, all data traffic going from one area to another must pass through the backbone routers. Distance Vector Algorithms In order for data to be transmitted from a source to a destination on the Inte rnet, the destination must be identified using some mechanism. That is, each possible destination for data transmission must be described with an address. The scheme currently used to address the internet space is the Internet Protocol (IP) version 4. The IP version 4 uses an address length limited by 32 bits. An example of an Internet address is 227. 130. 107.5 with the corresponding bit vector 11100011 10000010 01101011 00000101. An initial difficulty in managing the available address space was the implementation of a class structure, where large blocks of internet address space was reserved for organisations such as universities, leaving commercial applications with limited address space. Routing of data transmission in this address environment was referred to as class-full routing. To alleviate this problem of limited address space, the internet community has slowly evolved to a classless structure, with classless routing.In distance vector protocols, each router sends adjacent routers information about known paths to specific addresses. The neighbouring routers are sent information giving a distance metric of each one from a destination address. The distance metric could be the number of routers which must be used to reach the destination address, known as the ‘hop count’, or it could be the actual transmission distance in the network. Although this information is advertised only to the adjacent routers, these routers will then communicate the information with their neighbouring routers, and so on, until the entire network has the same information.This information is then used to build the routing table which associates the distance metric with a destination address. The distance vector protocol is implemented when a router receives a packet, notes the destination, determines the path with the shortest distance to the destination and then forwards the packet to the next router along the shortest distance path. One of the first distance vector protocols implemented on the Internet was the Routing Information Protocol (RIP). RIP uses the distance metric of hop count to determine the shortest distance to the destination address.It also implements several protocols to avoid having data packets pass through the same router more than once (router loops). The path vector protocol is a distance vector protocol that includes information on the routes over which the routing updates have been transmitted. It is this information on path structure which is used to avoid routing loops. Path Vector Protocols are also somewhat more sophisticated than RIP because an attempt is made to ‘weight’ each path based on a locally defined criteria that may not simply reflect the highest quality of service, but rather the highest profit for an ISP.The implementation of these types of router algorithms may be different in different parts of the Internet. When the algorithms are implemented inside an autonomous system, they are called Interior Gateway Protocols (IGP). Because the different autonomous systems that make up the Internet are independent from one another, the type of routing algorithm used within the autonomous systems can also be independent of one another.That is, the managers of each autonomous system are free to choose the type of algorithm which best suits their particular network, whether it is static or dynamic link-state or dynamic distance-vector. When the algorithms are implemented to control data transmission between autonomous systems, they are referred to as Exterior Gateway Protocols (EGP). The EGP connect all autonomous systems together to form the Internet and thus all EGP should use the same algorithm.The specific algorithm currently used as the EGP on the Internet is the Border Gateway Protocol (BGP), which is a type of distance vector algorithm called a path vector algorithm [9]. A path vector algorithm uses information about the final destination of the data transmission in additio n to the attributes of the neighbouring links. It should be noted that the BGP algorithm can also be used as a router protocol within an autonomous system and is called an interior BGP (IBGP) in that instance. This necessitates calling the BGP an EBGP when it is implemented as an EGP.

Analysis of Dickens’ Description of Fog In London in Great Expectations Essay

Dickens uses repetition of the word â€Å"fog† throughout this passage. The use of the repetition helps reinforces and emphasises how foggy it is, constantly reminding the reader of the peculiar weather. It also conveys the idea that it isn’t just a normal foggy day but a day with fog so peculiar and heavy that you have to repeat it several times to portray the idea of a heavy, unusual fogbound city. It is constantly repeated to remind us of how thick and strange it is. Usually fog isn’t particularly interesting to be repeated so many times.H e emphasise and focus is put on the fog to try and express and give an impression of an unusual and intense foggy atmosphere to the reader. Dickens also uses various prepositions in this passage.For example he uses prepositions in this quotes : â€Å"Fog up the river† ; † fog down the river† ; † fog on the Essex marshes†; â€Å"fog in the stem and bowl† ; â€Å"fog wheezing by†. The uses of these various prepositions help emphasise and convey the fact that fog is indeed everywhere (â€Å"fog everywhere†). In and out, up and down,quite literally everywhere which makes the reader vividly picture all London covered in heavy thick fog. Another way Dickens uses language to convey the idea of a fog bound London is through the technique personification. â€Å"Fog creeping in†, â€Å"fog cruelly pinching toes and fingers†, â€Å"fog wheezing by†. The use of personification brings the fog to life. The adverb â€Å"creepily† conveys an idea of the fog being a mysterious, sinister but yet eerily quiet being. â€Å"Cruelly pinching toes†, by using this personification it links to the idea that the fog is a sinister, sly being. The adjective â€Å"cruelly†, portrays the fog as a brutal, wicked person, it shows no remorse even though he if pinching † of a shivering little ‘prentice boy†. It shows the reader the force and greatness of the fog (even though it is serene and quiet as implied by the word â€Å"creeping†) which connects to the intensity and strength of the fog as mentioned before- creating an impression of a fog bound city. This contrasts against our normal impression of fog as a misty, subtle delicate weather but transforms this idea into a great menacing bully in the form of a mysterious fog. the phrase † wheezing by could make the fog seem like acranky old man, creeping in and out preying on young children. pinching, creeping,cruelly all have negative connotations portraying the fog as an evil dark being.

The Values Of Philosophy Essay Example | Topics and Well Written Essays - 1250 words

The Values Of Philosophy - Essay Example paper will analyze the value of Philosophy in several areas such as professional setting, educational world as well as in terms of critical thinking. If one takes a look at the way students study Philosophy, one can not help noticing that this discipline is great when it comes to structuring one’s mind and understanding of the world (Kelly). Indeed, while many think that a philosophy major provides a person with nothing, but a set of abstract knowledge about vague concepts, in reality it prepares one to a better understanding of such crucial areas of life as law, medicine, business or computer science. In other words, if one studies Philosophy, one will be able to analyze the above mentioned sciences easier compared to an ordinary person because of the helpful background that this disciple has provided one with. Another point that should be mentioned is that studying Philosophy also teaches a person how to express oneself in writing properly (Kelly). Indeed, nowadays it may be crucial to write a specific document in manner that would convey a particular message in a concise and clear manner making sure that the recipient will understand everything what the sender wanted to express. With the help of various tools, Philosophy helps a person to learn how to structure writing properly, avoiding simple mistakes that distort the meaning. What is why important is that Philosophy become irreplaceable when it comes to the issue of Business ethics. Indeed, if it had not been for this discipline, people could hardly understand what it is and the entire concept would not have emerged (Marcoux). At the present moment, the idea of Business ethic guides every business and it is virtually impossible to imagine a company that would not pay attention to it. Philosophy provides a person with a necessary set of concepts that make the idea in question understandable and applicable to a concrete situation. Moreover, Philosophy is often engaged when it comes to designing Codes of

Relationship Between the Characters in Winter Dreams by F. Scott Essay

Relationship Between the Characters in Winter Dreams by F. Scott Fitzgerald - Essay Example Dexter has American dream since he employed his efforts in pursuing the interest of his life. When he met Jones for the first time, he was attracted to her. He did not move, instead he spent a lot of time staring at the beautiful woman. This paper analyzes Dexter relationship with Judy. The relationship between Dexter and Jones seems to be a first sight love relationship (Becnel, 140). When Dexter saw Jones for the first time, he was glued to her. The attraction of Dexter to Jones influenced the choices that Dexter made. He was ready to quit his job because of the beautiful Jones. Dexter told caddy master that he was done with his job. He made this remarks after a strong attraction to Jones. He wanted to spend his life with Jones and would do anything to achieve that ambition. The extent to which he was attracted to Jones shows how true feelings could influence his decisions. Dexter left a low a paying job to seek a means that could help him win the heart of Jones (Fitzgerald 513). D exter’s decision to quit the golf club hanged on the influence of the eleven-year-old Jones who treated him like a junior. Jones undermined Dexter because of the wealth that her family had. The relationship that existed between Dexter and Jones was an intimate relationship. Dexter wanted Jones to be with him. He could not control or hide his feelings towards Jones. It was difficult for Dexter to make any decision that could keep him away from Jones. Dexter had a dream of winning the heart of Jones. He was convinced that wealth could help him win the heart of Jones. On the hand, Jones did not reciprocate Dexter’s love. In intimate relationship, partners need to exercise dialogue. Dialogue held between partners provides a chance for making correction and ironing out relationship differences. Jones did not offer any information that was transparent in their relationship. The relationship between Dexter and Jones portrays a theme of emptiness (Stanley 333). Dexter dream en ded when Devlin gave him news regarding the status of Jones. He took his time to know more about Jones life. Their conversation ends when his American dream of leading his life with Jones ends. The reaction of Dexter indicated the extent of love that he had for Jones. Though Jones had been out of his life for about seven years, he had a deep feeling for her. Life in the story ceases to have meaning because of the shattered dream of Dexter. He does not find any meaning to life since the dream in his entire life is meaningless. Dexter looked at his age and realized that he had spent his life chasing for a dream that could not come true. At the end of Dexter’s discussion with Devlin, Dexter saw the reality in their relationship. He realized that he had banked his hopes where they could not be appreciated. Sometimes a relationship could prove to be sour. When a partner does not reciprocate in a relationship, life in that relationship ceases to have a meaning. Dexter had spent his time acquiring wealth in order to meet the needs of his desired love. He knew that Jones could not accept him without wealth. He ventured into business with an aim of making wealth, which could sustain his life with Jones. Devlin message comes as a shock to the relationship. It shuttered the dream that Dexter had about Jones. It is important to note that Dexter knew that Jones had been married. Ironically, he felt that Jones could still

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COMPERATIVE STUDY TO DETERMINE THE BEST DIANOSTIC IMAGE MODALITY IN PERIPHERAL ARTERIAL DISEASE (PAD) - Essay Example Similar to pathology in the coronary arteries, the pathologic hallmark of the lesions involves plaques of atherosclerosis with calcium deposition, thinning of the media, patchy destruction of muscle and elastic fibers, fragmentation of the internal elastic lamina, and thrombi composed of platelets and fibrin (Duerschmied et al., 2006, 310-315). According to statistics delineated in different articles, the primary sites of involvement are the abdominal aorta and iliac arteries comprising 30% of symptomatic patients; the femoral and popliteal arteries consisting of 80 to 90% of patients, and the more distal vessels, including the tibial and peroneal arteries making 40 to 50% of patients (McDermott, 2006, S2). Mechanically and topographically, atherosclerotic lesions occur preferentially at arterial branch points, which are sites of increased turbulence leading to altered shear stress, and hence injury to the tunica intima. Epidemiologic and demographic data suggest that the distal vasc ulature is most commonly involved in elderly individuals, mostly in patients with diabetes mellitus (Marso and Hiatt, 2006, 921-929). The history and physical examination are usually sufficient to establish the diagnosis of peripheral arterial disease (PAD). An objective assessment of the severity of disease is obtained by noninvasive techniques. These include digital pulse volume recordings; Doppler flow velocity waveform analysis; duplex ultrasonography, which combines B-mode imaging and pulse-wave Doppler examination; segmental pressure measurements; transcutaneous oximetry; stress testing, usually using a treadmill; and tests of reactive hyperemia (Mohler, III, 2003, 2306-2314). In the presence of significant PAD, the volume displacement in the leg is decreased with each pulse, and the Doppler velocity contour becomes progressively flatter. Duplex ultrasonography is often useful in detecting stenotic lesions in native

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Security Frameworks Comparison - Case Study Example Therefore, COBIT acts as a supporting toolset that enables managers to bridge the gap between technical issues, control requirements and business risks. The business orientation of the Control Objectives for Information and Related Technology consists of linking business goals to IT goals, providing maturity and metric models to measure their success and identifying the associated obligations of business and Information Technology process owners. The unique nature of COBIT is that: its focus is illustrated through a process model that subdivides Information Technology into 4 domains and 34 processes in line with the responsibility areas of planning, developing, running and monitoring, providing the much needed view of IT (Brand, 2007). Founded in the year 1901, the National Institute of Standards and Technology is one of the US oldest physical science laboratories. NIST measurements support the smallest of technologies to the largest and most complex of human made creations. Much of its developed technology ranges from earthquake resistant skyscrapers to wide-body jetliners to world wide communication networks. The lab assists the industry in the development of technology that helps in: improving product quality, modernization of the manufacturing processes and facilitation of rapid commercialization of products based on current scientific discoveries (NIST monograph, 1900). Data security standard (PCIDSS) is one of the security standards offered by PCI security standards council. The PCI data security standard (PCI DSS) provides an actionable framework for building a full-bodied payment card data security process which comprise of detection, prevention and appropriate reaction to security incidents. Data Security Standard (PA-DSS) was developed to help in provision of definitive data standard for software vendors that develop payment applications. Its

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Adult education and postmoderism - Essay Example Knowledge is often constructed by men, and so women may have difficulty accessing it. Most knowledge is facts, figures, and well-thought-out theories (produced by men), which leaves learners, both male and female, out of the picture. Personal experiences become secondary to memorizing a set way of doing things and demonstrating how well the learner memorized it through tests and quizzes. When learning is disconnected from learners, it’s difficult to apply to everyday life or understand where the learner fits into the process. When learning is constructed by a male-dominated culture, that removes it even one more step from women learners. Women may feel they have nothing to add to the knowledge base or the learning experience. If the knowledge base is constructed by a male-dominated structure, it affects the learners and instructors, even if those are all women. Creating connections between each individual and the learning, and each individual and every other individual in the learning environment, promotes understanding of the lessons and allows learners to both make it personal and to add to it as they see fit. Seeing each person in the classroom as unique and valuable enhances how much is learned, and changes the dynamic process. Another thing feminist theories are trying to overcome is the idea that women must construct identities to deal with life situations, rather than simply being themselves. When women learners have to construct a false identity in order to participate in learning environments, much of the impact of the knowledge can be lost for them. If we have to concentrate on supporting other group members during a group project, for instance, our own thoughts and feelings on the subject matter become secondary to cheering each other on. The teacher can also experience tension in the learning environment when there are conscious or subconscious authority issues. If a teacher sets

Documentary Realism in Films Movie Review Example | Topics and Well Written Essays - 1500 words

Documentary Realism in Films - Movie Review Example In the discussion and analysis in this paper, three kinds of films are analyzed based on their social function-specifically, how each film represent a criticism of war and conflict at different periods in history. These films are "Fahrenheit 9/11," "Life is Beautiful," and "The Aviator," which are categorized as documentary, fiction, and non-fiction films, respectively. These films are analyzed and interpreted based on their ability to provide a critical look at the conflicts that occurred and which became the basis-primary or otherwise-for the development of the narrative in each. The analysis posits that the three films criticize war and conflict in various ways. "Fahrenheit 9/11" criticizes the political instability caused by the offensive attack that US waged against Iraq, causing greater discord between the Middle Eastern nations and US and its allies. "Life is Beautiful" reflected the absurdity of World War II, as millions of lives, particularly Jews, were unnecessarily lost as a result of the genocide imposed on them by Adolf Hitler of Germany. Lastly, "The Aviator" provides an in-depth look at the lives of the people in the context of Howard Hughes' life and using the World War II as the socio-political background. In it, the film reflected the politico-economic machineries that motivated and supported World War II, uncovering also the politics that occurs 'behind the scenes,' the politicking of businessmen and aircraft manufacturers in order to benefit best and profit the most from the war. Apart from these comparisons among the three films in terms of their depiction and critical interpretation of war and conflict, this paper also looks into the differences in the execution of the directors in depicting these interpretations into film. For "Fahrenheit," Moore's critical look at the 9/11 bombing and US invasion of Iraq is more explicit and direct, in the sense that real film clips were used to critically interpret the Bush administration's actions before, during, and after the tragic event. "Life" provides a different execution as well, weaving its criticism into the story of Guido's family as Jews persecuted for their race and religion. However, unlike Moore's "Fahrenheit," Benigni's film depicts a fictional scenario put into a real event in human history. "Aviator," meanwhile, illustrates the life of Howard Hughes, depicting his life and achievements and chronicling the events relevant and significant to his development as an important personality in both the entertainment and automotive businesses, as well as politics. In understanding the contrasts among "Fahrenheit," "Life," and "Aviator," it is vital to understand first their crucial differences. "Fahrenheit" is a realist documentary, because it provides real images and accounts of events surrounding the 9/11 bombing, events that Moore had organized in a manner that provides support to his criticisms and arguments against President Bush and the administration. As explicated by Bordwell and Thompson (1997), a documentary does convey truth in that it illustrates "events as they actually occur," but it can also be depicted realistically when the director 'controls the editing of the images' to be included in the film. A documentary is realistically portrayed even if these

Comparative International Accounting Essay Example | Topics and Well Written Essays - 3000 words

Comparative International Accounting - Essay Example ntal bodies to determine what taxes a business must pay; and occasionally by customers to determine the price to be paid when contracts call for cost-based payments. (Encyclopedia Britannica, 2007) The aim of this paper is to critically compare and contrast the accounting methods, structure and regulation in Canada with the UK including a critical and detail analysis of both current issues and academic literature surveyed relevant to the country. To begin we will talk briefly about the evolution of Accounting in both countries. According to Baylin et al (1996), Accounting standard setting in Canada has undergone a number of significant structural adjustments since the late 19th century. Following Canada’s emergence from its colonial status and due to the establishment of new trading partners, there was a change in the demand for accounting and the accounting standard setting process in Canada (Baylin et al, 1996). There have also been changes in the source of authority for standard setting, the range of interests were formally included in the standard setting process and changes in relative influence of technical versus political concerns. Canada continues to have one of the few private standard-setting processes in the world. (Baylin et al, 1996). No central source of accounting standards existed in Canada before 18646. Accounting standards were governed by common law. For example, the Dominium Insolvent Act was introduced in 1864 and was the first legislation to recognise the need for the regulation of accounting and the quality of financial information. (Baylin et al, 1996). Following this act, Canada witnessed the first real appearance of public accountants to act as â€Å"Official Assignees† for the handling of the affairs of estates, which were bankrupt. Foreign influences, government, and the internal needs of the early accounting firms drove the accounting profession, which was still at its infancy. (Baylin et al, 1996). As a result, the legal

Maybank online banking system Essay Example for Free

Maybank online banking system Essay Maybank is a trade name for Malayan Banking Berhad and is the largest bank and financial group in Malaysia with significant banking operations in Singapore, Indonesia and the Philippines. Maybank was founded by Malaysian business tycoon Khoo Teck Puat, who died in 2004. The bank also has large interests in Islamic banking through Maybank Islamic Berhad and insurance via its Etiqa subsidiary. Maybank is the largest bank in Malaysia with 401 domestic branches. Maybank operates consumer banking, business and corporate banking as well as private banking services, through a network of 401 branch offices and more than 2,900 automated teller machines in Malaysia Beside its commercial banking network, Maybank operates a number of specialized subsidiaries in the insurance, investment banking and assets management, and finance sectors. Online banking is becoming more and more popular because the advantages of online banking for the majority of banking users. You can apply most of it without leaving your home, if you wish. Internet banking is a great secure and convenient way to handle your cash flow.By using the internet banking, you can make most of different transactions. It is possible to pay bills directly from the checking account online. This saves you the cost of a stamp and saves your times. It also provides you more leeway in how quickly you need to pay your monthly bill. In case you need to mail it, you can send it out long ahead of the due date.Consumers will become more comfortable with doing the majority of their shopping online. Maybank online banking system has provided its full day access to bank accounts and advanced services. Currently, users can now check their finances status with a click of button. They can also view their bank statements, check the balances or manage some transaction by using the online banking system. Recently Maybank had taken a huge step by announcing its internet banking services for the customers. This is due to achieve the same standard as other conventional banking facilities that are in Malaysia. In this era of technology, people tend to seek for things or option that could benefit them in many ways.

Moral Perspectives On Euthanasia Philosophy Essay

Moral Perspectives On Euthanasia Philosophy Essay Should individuals, especially terminally ill-people in excruciating pain, be able to end their lives? If so, may they hasten their deaths only be refusing medical treatment designed to sustain their lives, or may they take active measures to kill themselves? Can they ask others to assist them? Who can they ask: their spouses? Close friends? Their doctors? Should they expect the law to support their decision?  [1]  These are commonly asked question when debating on euthanasia. In this paper I shall try to answers these questions from different moral perspectives. According to Vincent Barry, euthanasia is the act of painlessly putting to death a person suffering from terminal or incurable disease or condition  [2]  . To elaborate, euthanasia is deliberate act; it is painless killing and is performed to people with incurable disease or irreversible coma. In addition euthanasia is performed only to those patients who have confirmed diagnosis of untreatable disease, are at their terminal stage of life and are suffering from intense pain or other painful medical symptoms. The term euthanasia is often used interchangeably with physician assisted suicide/death as it is usually assisted or advised by a physician. There are six categories of euthanasia. However it can be classified in two different ways. First is the way life is taken from the patient suffering from terminal disease, which is known as active or passive euthanasia. Active euthanasia is an act of killing the person by injecting lethal drugs to cause immediate and painless death. While passive euthanasia is omitting the act of saving a persons life with incurable disease, and is not benefiting from the existing medical treatment. Hence passive euthanasia is allowing the patient to die (Daniel Gorman, 1998). Moreover it could be painful or painless depending on the present condition of the sufferer. Not everyone agrees with classifying passive euthanasia under the category of euthanasia as it is not a deliberate act of killing, and is usually prolong and painful. Therefore allowing the patient to die can be morally permissible (Gay-Williams, 1979). Others argue killing and allowing dying holds same moral position in some cases and therefore should be answered separately (James Rachels, 1975). The second method of classification of euthanasia is (a) voluntary i.e. the sufferer who is competent adult is giving consent for particular form of treatment for euthanasia. (b) Non-voluntary euthanasia i.e. when the consent is given by some other person because the patient to die is not eligible to give consent (Vincent Barry, 1985, pg 195). Different moral positions and arguments are held for different forms of euthanasia. Therefore in this paper I would discuss voluntary active euthanasia from Kantian and utilitarians perspective. In additions I would be discussing arguments for and against voluntary active euthanasia. Immanuel Kant focuses on actions and labels an action morally right if it is done for the sake and respect of duty. For him rational being is someone who guides his will and duty with reason. In addition he talks about principal of categorical imperatives that actions are morally correct if a person can will it to be universalized. Also he says not to use human beings as mere beings. Kant would look at voluntary active euthanasia as a form of suicide. In his groundwork for metaphysics of morals he talks about it as Act in such a way as to treat humanity, whether in your own person or in that of anyone else, always as an end and never merely as a means  [3]  . So a person choosing euthanasia is using himself as mere being and is not respecting his own rationality. Hence Kant would strictly forbidden voluntary euthanasia as the person in pain inclined to take his life, is not acting according to duty and is therefore always immoral. The action is moral as Kant says if the unfortuna te one, strong in mind, indignant at his fate rather than desponding or dejected, wishes for death, and yet preserves his life without loving it not from inclination or fear, but from duty, then his maxim has a moral worth  [4]  . There are many schools of thoughts on utilitarianism but John Stuart Mills theory on utilitarianism and euthanasia will be discussed. Mills ethical theory mainly talks about pleasure and avoidance of pain. According to him, actions are right in proportion as they tend to promote happiness, wrong as they tend to produce reverse of happiness  [5]  . Hence voluntary active euthanasia can produce happiness for a number of people. Firstly the persons suffering from pain will get rid of it and having control over their lives would give pleasure. Secondly the family of the patients, who feel the pain of their close ones, and who are spending lots of money in the treatment, will ultimately be free of pain. Therefore utilitarians would allow active voluntary euthanasia because it follows greatest happiness principle. In my point of view, voluntary active euthanasia can be morally permissible. Keeping utilitarianism in mind, active voluntary euthanasia holds many advantages. It terminates the suffering and pain of the terminally ill persons and their families. In addition the material resources and paramedical staff needed to keep alive patients, whose death is certain, can be used for those patients who have curable diseases. Moreover families of such patients suffer from economic burden of medical expenses, hence it is also relieved. Lastly and most importantly, euthanasia gives a sense of autonomy and control to people, to decide how and when their lives should end, when death with incurable disease is certain. Now I shall converse the arguments for and against the act of voluntary active euthanasia. The first argument made by most of the opponents is that act of euthanasia is against the divine will of God and it interferes in the natural processes that God has formulated for human beings. As argued by Gay-Williams (1979), man as trustee of his body act against God, its rightful possessor, when he takes his own life. Hence killing human life is violation of Gods commandments. However Vincent Barry in his writings answers this argument in the light of modern medicine. He argues that contemporary advances in medicine have also interfered with the divine plan of God as it has prolonged peoples life who would have died long before. Hence if active euthanasia is said to be immoral, then prolonging peoples life against the will of God can also said to be immoral. Opponents of euthanasia argue that diagnosis made by physicians may at times be wrong. Therefore a patient diagnosed as having incurable disease might be an error. That is a mistaken diagnosis is made, and patient is forced to go for euthanasia. In addition they claim that physicians as human beings are inclined to make errors therefore euthanasia leads to an immoral and unacceptable act (Hooker, 2002, pg 28)  [6]  . In answer to this argument, proponents respond that there are very few cases in which such error is made. This doesnt imply that euthanasia shouldnt be legalized. If euthanasia is to be legalized and practiced, only medical experts would be eligible to make a diagnosis. Further to reduce the error of misdiagnosis, three medical experts shall discuss the diagnosis and come to the conclusion of whether euthanasia is applicable or not. The third argument made by the opponents is regarding new treatment options. They argue that what if new treatment modalities are available after acting on euthanasia? The outcomes would be terrible. Moreover people and physicians would become hopeless as soon as they encounter fatal disease and would not look for new treatment options. Brad Hooker (2002) talks about two standards that need to be followed for euthanasia. First he says that as euthanasia is always implied at the end stages of a fatal disease, where there is no possibility of the diseased being benefited from new medical treatments, hence in such cases active voluntary euthanasia can be entertained. Secondly on the other hand, if there is a possibility that a patient might benefit from any innovative medical treatment, euthanasia should always be restricted. Slippery slope argument on the legalization of voluntary active euthanasia is also made by most of the opponents. They argue that once we have allowed voluntary euthanasia, in no time, non voluntary euthanasia will also be allowed and legalized. Hence doctors and sufferers family will start killing them without their consent. These people will be killed for wealth they posses, doctors will kill them so they can save hospitals resources and so on. Thus it will lead to a chain of reaction leading to devastating results. The Stanford encyclopedia of philosophy cites a study done in Netherlands in 1995 to explore the reality of slippery slope argument. The researchers found the slippery slope argument groundless. That is to say, there a clear distinction between voluntary and non voluntary euthanasia, therefore there is no point in saying that legalization of active euthanasia will lead to abuses of non voluntary euthanasia. Moreover if active voluntary euthanasia would be legalized, it would need to be carefully drafted. And the law would have to be rigorously policed, to prevent abuse (Hooker, 2002, pg 30). In the conclusion, as euthanasia has six classifications, each type should be evaluated for moral worth. Some opponents might argue that good palliative care and pain relief measures are adequate and hence euthanasia is not required. However regardless of our maximum effort to provide best palliative care, euthanasia will always be picture. Moreover the price for not allowing active euthanasia will be paid by sufferer whose suffering and pain will increase (Gorman, 1999, p.860), thus active voluntary euthanasia should be legalized. However in order to ensure that people do not misuse it, law should be strictly implemented. In this way, the victim would feel autonomous and will die with dignity.