Wednesday, October 30, 2019

Aviation Safety Essay Example | Topics and Well Written Essays - 2750 words

Aviation Safety - Essay Example Success in this endeavor is defined by the extent to which aviation security personnel remain one step ahead of terrorists. When the "Shoe Bomber," Richard Reed, was able to board a transatlantic commercial airliner following 9/11, it marked a monumental failure of aviation security. Since then the sight of airline passengers in security checkpoints removing their footwear has become commonplace. Obviously, adjusting security to account for methods of terror that have already been attempted is essential. However, the real success of security happens when those threats are predicted and guarded against before anyone actually carries them out. Among all such threats that have been contemplated, there is one that stands out as a glaring risk about which shockingly little has been done. That is the potential for checked luggage and cargo loaded into the hold of an airplane to be rigged with explosives. To date, no airline or airport routinely screens checked bags and cargo for explosives. Some small scale pilot projects are in the works to test methods of doing this. Nevertheless, it is quite surprising that five years after 9/11, a terrorist could go to an airport and check through a bomb-laden suitcase that very likely would make it aboard a commercial airliner. ... ee's antitrust subcommittee, faulted airlines for not ensuring that a person who checks luggage actually gets on the flight, already the practice in Europe. At the same time, he noted, checked bags are not routinely screened for explosives." The AP went on to quote Senator Kohl stating, "On a given day, a group of saboteurs could load up 12 different airplanes across the country with explosives, go home, and we would have a disaster." The airline industry responded that it would be impossible to match luggage to passengers given the structure of the U.S. air travel system; and even if it were possible, such an undertaking would not thwart a terrorist who was willing to die by boarding the flight on which his/her checked bags contained a bomb (Associated Press, 2001). Donald Carty, President and CEO of American Airlines, asserted that a bag to passenger matching system would ultimately lead to reduced flights and layoffs. Senator Kohl described a two-pronged problem with aviation security. The first, and arguably the key, issue is that checked luggage makes its way on board commercial airliners without being screened for explosives or other potential threats. Secondarily, the failure to ensure that those who check luggage actually board their flight makes it possible for someone to place a bomb aboard a flight with no risk to him/herself. Arguably, if the former problem were adequately addressed, then the latter one would not be nearly as great a concern. Many would consider it shocking that even before 9/11 checked luggage was not screened. The procedure of going through airport security checkpoints, scanning carry-on items and going through metal detectors fostered a false sense of security in many people. Surely, many would think, if such precautions were taken with

Sunday, October 27, 2019

An Overview of Network Topologies

An Overview of Network Topologies A network topology refers to the way in which nodes in a network are connected to one another. The network structure defines how they communicate. It is the arrangement with which computer systems or network devices are connected to each other. Topologies may define both physical and logical aspect of the network. Both logical and physical topologies could be same or different in a same network. Point-to-Point Topology Bus Topology In this topology, all devices share single communication line or cable. This central cable is the backbone of the network and is known as Bus. Every point communicates with the other point through this Bus. This topology may have problem while multiple hosts sending data at the same time. Therefore, Bus topology either uses CSMA/CD technology or recognizes one host as Bus Master to solve the issue. It is one of the simple forms of networking where a failure of a device does not affect the other devices. But failure of the shared communication line can make all other devices stop functioning. Both ends of the shared channel have line terminator. The data is sent in only one direction and as soon as it reaches the extreme end, the terminator removes the data from the line. A signal from the source is broadcasted and it travels to all workstations connected to bus cable. Although the message is broadcasted but only the intended recipient, whose MAC address or IP address matches, accepts it. If the MAC /IP address of machine doesnt match with the intended address, machine discards the signal. A terminator is added at ends of the central cable, to prevent bouncing of signals. A barrel connector can be used to extend it. Below I have given a basic diagram of a bus topology and then have discussed advantages and disadvantages of Bus Network Topology Advantages Disadvantages It is easy to set-up and extend bus network. If the main cable (Bus) encounters some problem, whole network breaks down. Cable length required for this topology is the least compared to other networks. Proper termination is required to dump signals. Use of terminators is must. Bus topology costs very less. It is not suitable for networks with heavy traffic. Linear Bus network is mostly used in small networks. Good for LAN. Security is very low because all the computers receive the sent signal from the source. Table 1 Star Topology Ring Topology       Mesh Topology Tree Topology Hybrid Topology IP Addressing An Internet Protocol address (IP address) is a numerical label assigned to each device (e.g., computer, printer) participating in a computer network that uses the Internet Protocol for communication. An IP address serves two principal functions: host or network interface identification and location addressing. Two versions of IP technology exist today. Traditional home computer networks use IP version 4 (IPv4), but some other networks, particularly those at educational and research institutions, have adopted the next generation IP version 6 (IPv6). Internet Protocol Version 4 (IPv4) IPv4 is the fourth version in the development of the Internet Protocol (IP) and the first version of the protocol to be widely deployed. IPv4 is described in IETF publication RFC 791 (September 1981), replacing an earlier definition (RFC 760, January 1980). IPv4 Classes Class IP Start Range Purpose A 0 127 B 128 191 C 192 223 D 224 239 Multicast E 240 255 Research Table 2 Class A Class B Class C Internet Protocol Version 6 (IPv6) IPv4 vs IPv6 Comparison Feature IPv4 IPv6 Deployed 1981 1999 Size 32 bits (4 Bytes) 128 bits (16 Bytes) Unit Allocation 8 bits X 4 16 bits X 8 No of IPs 232 = 2128 = 3.4 X 1038 Unicasting Yes Yes Multicasting Yes Yes Broadcasting Yes No Any casting No Yes Address Format Dotted Decimal Notation (192.168.1.1) Hexadecimal Notation (3FFE:F200:0234:AB00::) Table 3 : IPv4 vs IPv6 Network Models Network models define a set of network layers and how they interact. There are several different network models depending on what organization or company started them. The most important two are: ISO OSI Model The International Standards Organization (ISO) has defined a standard called the Open Systems Interconnection (OSI) reference model. This is a seven-layer architecture listed in the next section. TCP/IP Model This model is sometimes called the DOD model since it was designed for the department of defense It is also called the internet model because TCP/IP is the protocol used on the internet. ISO OSI Model Layer No Layer Name PDU Description 7 Application 6 Presentation 5 Session 4 Transport 3 Network 2 Data-link 1 Physical VLANS Ethernet Network Standards No Tasks Week 1 Week 2 Week3 Week4 1 2 3 4 5 6 Table 5: Gantt Chart TutorialsPoint, 2017, DCN Computer Network Topologies. [Online]. Available at [Accessed on 18th February 2017]

Friday, October 25, 2019

Osama Bin Laden and Al Qaeda :: History of Osama Bin Laden

Osama Bin Laden who is better known as Al Qaeda's Emir-General was born on July 30, 1957 in Saudi Arabia to Muhammad bin Judah bin Laden and Humid. He was the seventeenth child out of fifty-two. Osama went to Kin Abdulaziz University where he began studies in economics and management but left college in his third year. While at the university he learned Islamic studies and became very intrigued with this religion. Osama's father always urged his children to refrain from politics and religion debate, but Osama seemed interested in government and international politics. In 1973 Osama focused his time and energy on resources and advancement of Islam and Islamism. He also gained higher knowledge in mujahid fighting with wealth and sake for Allah. Osama is well established among the Afghan people. He is one of the scholars of the Jihad as well as being the main commander of the mujahideen worldwide. Dr. Abjullah Azzam leading Islamist influenced Osama for the next 10 years. Together in 1984 the two set up the Afghan service Bureau. Osama's first cam, al-Ansar, in Jaji in Afghanistan's Pakita province was built. In 1982 Essam al-Ride, a flight instructor, joined al Qaeda where he served as procurement officer and Osama's personal pilot. During this time Osama's father died and he inherited a huge sum of money, which he invested. He began to build several training camps and quest houses for the Arab mujidian's. In the mid 1980's Osama began to import machinery, building roads, cave complexes, and supervising the blasting of massive tunnels. Osama then began to win over the Afghan people by becoming humble and starting to live a simplistic life. He seemed to have the ability to befriend and communicate with fighters and live with the Afghan peasants. During his stay on the Afghan-Pakistan border his religious convictions began to deepen. In 1987 what was known as the Lion's Den Operation occurred, exposing Osama to Soviet poison gas. He suffered minor injuries from this attack. This in turn upset him and his dislike of the soviets grew. Osama's wealth and influence made him a natural leader of the Arab Mujahidin people. Osama spent much of his time after this on the front line while Azzam was the one who conceptualized Al Qaeda.

Thursday, October 24, 2019

The Beloved Country

Cry, The Beloved Country, a novel by South African Alan Paton, is the story of a father's search for his son, an experience which opened his mind to the prejudice and poverty prevalent in his country. As the story opens, Reverend Stephen Kumalo, is summoned to go to Johannesburg to help Kumalo's sister who was very ill. He goes to help his sister and also to look for a long-lost son, Absalom, who has gone to the city and never came back.When Kumalo arrives at Johannesburg, he discovers that his sister has become a prostitute and that his brother, John, has become a politician. He visits his brother for help in locating his son and from him Kumalo learns that his son worked at the Doornfontein Textiles Company with John's own son years before. From the factory, Kumalo is forwarded to a couple of addresses until he eventually finds his son in prison. Absalom killed a white man, Arthur Jarvis, who was also a proponent and activist for racial equality.Furthermore, he also meets a girl wh ich Absalom got pregnant and would have married before he was sent to prison. Kumalo talks to his son and finds a lawyer for him. The second part of the novel shifts to the viewpoint of James Jarvis, the father of the murdered Arthur. The police inform him of his son's death and he flies from Ndotsheni to the city to attend his son's funeral. There he learns the activities of his son and sets out to continue his cause. He also meets Kumalo whom he has to comfort and forgive.Absalom is found guilty of the murder and sentenced to death. Before Kumalo returns home to Ndotsheni, he marries his son to the pregnant girl and brings her and his nephew with Gertrude to the village. Back in Ndotsheni, he and Jarvis comes together to plan a way to help the village which at the time has been experiencing drought. The novel ends with Kumalo going up on a mountain on the evening of his son's execution. As the dawn breaks, he contemplates on his life, the blessings he has received, and of South Af rica and its social problems.How the novel relates to culture and values The novel takes a look at how elements in society, whether they are events or changing situations, affect the culture and values of a country. Cry, The Beloved Country explores how the social situations between the black and white races promote a culture of apartheid in South Africa, threaten the loss of the long-held values of the natives, and cause other social illnesses that plague the country even in contemporary times.Paton uses the story of Reverend Kumalo to define the larger problems discussed in the novel. The most obvious of these is how the divisions among the peoples of South Africa have been causing a series of problems that threaten to destroy the entire country. The more affluent and privileged whites are claiming the lands which the black natives have long revered and cultivated. As a result, more blacks are leaving the countryside for the cities where they believe they could find more meaningfu l and better-paying jobs as workers in industries.This results to a breakdown of the tribal system and the loss of previously strong-held beliefs and traditions. When these natives arrive in the city, they find that the situation is worse in that the urban areas themselves plague the black population with poverty and injustices. In retaliation, they commit violent crimes against the more privileged white people. The fear among whites against â€Å"native crime† and the hate of the blacks against â€Å"white injustice† fuels a cycle of violence and further chaos for the whole South African country.Yet, instead of being a pessimistic look at the situation, the novel would like to promote the values of kindness and cooperation among races to create change and a better future for the country. The friendship which evolves between Kumalo and the white Jarvis contains the author’s sentiments of everyone coming together instead of fighting each other to solve the basic problems of both the countryside and the urban areas. Paton promotes the values of family and religion as means by which the lost values could be reclaimed. Reference Paton, Alan. Cry, The Beloved Country.

Wednesday, October 23, 2019

Charles Dickens Essay

One lesson we witness in A Kestrel for a Knave also aims to teach the pupils about facts. However this lesson is taught by Farthing who is caring and a more fatherly teacher and this is communicated by his name. Mr Farthing has used his kind personality to gain some respect from the boys in the class. Although the lesson has the same content as the lesson in Hard Times during the lesson it becomes obvious that Farthing’s teaching is different. He manages to involve Billy, who is normally quite shy and lacking motivation, positively in the lesson. Farthing teaches in a more relaxed way and lets the lesson flow as well as welcoming input from the boys. He encourages Billy to participate and makes him feel special as he has something interesting to share. Farthing lets Billy’s thought tumble out and does not cut him short. Billy tells all about his bird, which he has raised and trained, and Farthing seems genuinely interested † ‘Jesses, how do you spell that?’ † He writes words on the board, allowing the whole class to learn about Billy’s unusual talent. Billy becomes the teacher for a while and as Farthing is not controlling like Gradgrind he allows this to happen. The lesson becomes full of individuality as Billy shares his unusual hobby and his confidence grows. This would never have happened in a lesson taught by Gradgrind, he would never encourage a pupil to take over his position and would think a pastime like Billy’s ridiculous. The way in which Farthing nurtures Billy’s thoughts reflect the way in which Billy has nurtured Kes. The time and devotion that Billy has shown the bird is matched, although on a smaller level, by the way Farthing waits for Billy to talk and persist to question him gently as if he knows Billy has a lot to share. Another contrast between the two schools is the way in which Billy and his classmates’ behaviour changes depending on the teacher, whereas Gradgrind’s pupils are always the same. The different methods of teaching present at Billy’s school become obvious when the PE teacher Sugden is introduced. Sugden is a bully and again Hines has highlighted the teacher’s personality with his name, as Sugden is a thug. Billy dislikes PE and does not have a PE kit, as his family cannot afford to buy him one. He arrives late to the lesson as he has been talking to Farthing. Instead of discreetly giving him a kit to wear Sugden mocks Billy in front of the other boys. The way in which Billy is treated provokes him to answer back and be cheeky. Sugden’s verbal bullying brings out the negative aspects of Billy’s personality. Not only does Sugden verbally bully his pupils but as a big man he does not hesitate to physically abuse them too. â€Å"He hit Billy twice with the ball, holding it between both hands as though he was murdering him with a boulder.† The whole lesson is a bullying game for Sugden. There is an absence of skills taught and so the lesson consists of a game of football in which Sugden is the captain of one of the teams as well as being the referee. He bullies the opposing team as well as his own teammates if they make mistakes. His attitude is immature and shows no sportsmanship or fairness, two lessons which should always be reinforced in PE lessons. His negative attitude has a clear affect on the boys, who leave the lesson cold and uninspired. The education system presented by Charles Dickens is extreme and unnecessarily harsh. However the title Hard Times makes it seem like Dickens is writing honestly about a time which lead to harsh methods of education. He highlights the naivety of the people as now teaching methods have improved and young people are encouraged to be themselves and achieve the best that they can. Satire is used by Dickens to emphasize the mistakes of the system. Charles Dickens could of attended a school like the one in Hard Times and so I think he aims to make the problems obvious to people who otherwise might not notice the wrongs in society. Barry Hines also writes the truth about the education system in his era and I think he also aims to highlight the incorrectness of the organization. However Barry Hines writes more realistically as the book is more recent and therefore easier to relate to. Both authors present systems, which now seem very wrong but at the time they were thought of as acceptable. Both books probably contain memories of the authors’ school days and particularly in A Kestrel for a Knave the scenes seem very believable. I could conclude that neither system would be justifiable now but in their time the schools seemed fair.