The Role of Corporate Governance Mechanism of Independent Directors Essay

The Role of Corporate Governance Mechanism of Independent Directors - Essay Example The mechanism suggests that the Board of Directors should comprise of an equal numbers of executive and non-executive (independent) directors. Executive directors are responsible for the management of the company’s operations whereas the non-executive directors, which are appointed by the shareholders, are responsible for the supervision of the executive directors’ performance as a whole. Under the framework, the independent directors are responsible for setting up board committees, which govern the performance of the board. These committees include audit committee, remuneration committee and nomination committee. The audit committee supervises the reporting of the financial statements between the management and the shareholders of the company, remuneration committee is responsible for devising remuneration packages for the executive directors of the board after considering their performance and the nomination committee is responsible for nominating directors that can b ecome the part of the board after elected by the board of directors. This whole framework is then observed in the real life examples of various organizations in UK, so as to see how effectively the mechanism has been applied and how well it is performing in achieving the main purpose of the framework. The Role of Corporate Governance Mechanism of Independent Directors According to the Cadbury report (1992), Corporate Governance has been defined as ‘the system by which companies are directed and controlled (P 15, paragraph 2.5).’ The system states that the board of directors is assigned the responsibility of governing the companies on the behalf of the shareholders, whereas the shareholders are in charge of appointing a board of directors along with auditors, so that they can be satisfied that a suitable system of governance is in place. In this paper the mechanism of independent directors, defined by the Corporate Governance, will be discussed to see how this mechanism works for the effective execution of governance. The concept of independent directors was originally acquired from the Anglo-American model of Corporate Governance, where there was a unified structure of board of directors. The main reason behind the concept was to apply checks and controls where there was a separation between ownership and control of the organization (Ali and Gregoriou, 2006). Recent progress in economic theory suggests that the appointed board of directors play a vital part in the effective governance of a corporation. With the authority to hire, fire and compensate the senior management of the company, the board of directors ensures that the problems relating to the conflicts of interest among the shareholders and the management are resolved and controlled. This contributes to economizing the transaction costs (also called the agency costs) that arises as a result of the separation of ownership and control, thus facilitating the existence of an organization as an open corporation (Baysinger and Butler, 1985). The basic agency problems that arise as a consequence of the separation of control and ownership include; managers acting in order to serve their personal interests, non-transparency of financial performance between the managers and the shareholders in ord er to portray a better picture of the company’s performance by keeping the shareholders in the dark and the management’s motivation to focus on short term performance and manipulation of the financial performance in order to secure incentives (Rezaee, 2007). In order to overcome these issues corporate governance defined a framework of board of directors to introduce independent direc

Should young children be shielded from fear-inducing events, like Essay

Should young children be shielded from fear-inducing events, like Halloween, or should they be allowed to have the human emotion - Essay Example However, despite the fact that quite a number of the children enjoy the Halloween images, a large number of the children development experts believe that the holiday psychologically damages most of the children. These experts favour the protection of the children from the intense effects of Halloween. Other experts argue that fear is a natural human emotion, and as such, it is harmful preventing children being afraid. It is wrong to shield children from fear-inducing events like Halloween, and thus, it is important to subject them to human emotions of fear. Such situations act as means of training children to have fear-management skills, and thus are very important. According to Pain and Susan (2), fear is an emotion induced by a perceived threat, which causes people, or animals to draw away from any fear-causing situation immediately they get that feeling. Fear is very important to children and other people due to a number of reasons. As children grow up, we expect them to become bo ld and brave adults. A brave person is one who can tackle any situation whenever it occurs to them. Therefore, a brave person does not run away from a challenging situation, but faces it with their right senses. This is the main reason why children should face both fear-inducing and scary situations such as the Halloween. Halloween, being one of the most controversial festivals in the history of Americans continuously receives positive and negative criticisms. One of the major reasons for its negative criticisms is the kind of images it draws in the minds of the young children. Halloween images of children dressed in scary costumes create anxiety and fear among the young children. This is the main reason why most of the people argue that children should not be part of the event. Further, experts point out that most of the children undergo traumatizing situations if they were to face such situations. On the other hand, their opponents argue that fear is a necessity to the growth and development of a human being. At an early age, the biggest source of fear for young children is Halloween. Therefore, they should take part in the event for experiencing the scary images of Halloween. These images make them brave people in future, making them confident enough to handle any challenging situation. Life is full of fear and anxiety, as it is characterized by incidences of high levels of uncertainty and anarchy. People cannot choose the kind of situations that they pass through in their course of life. Therefore, we have to be always vigilant enough to handle any situation whenever it happens. Situations that are likely to cause fear to adult people include the site of an accident, adventurous situations, very serious decisions that are very costly, new places and meeting new people. Emotions characterizing such situations are overwhelming to the people involved. While it is impossible to avoid such situations, we can prepare for them by having the ability to control our fear. Too much fear could escalate aq problem, especially in the event of the happening of an accident. A very emotional person, with little experience of emotional situations that require braveness can panic and cause an avoidable accident. The fact that such a person has no knowledge of facing such a situation, as well as what they should do in such circumstances lead to panic and loss of critical thinking. As such, they end up worsening a situation that if handles properly, is preventable. One of the reasons why people

Chinese photographer, Yang Fudong Essay Example | Topics and Well Written Essays - 250 words

Chinese photographer, Yang Fudong - Essay Example It is a cinematographic adaptation of the traditional Chinese stories. Yang is known for coming out with some of the most refreshing and impressive works in the contemporary Chinese cinema (Yu 35). Yang’s films and photos are well known for their psychological gravity and density (Yu 35). His films and photography tends to delve on the most fundamental philosophical questions marking the human existence in an intensely visual format (Yu 35). The hallmark of Yang’s art is that his photos and films aspire to blend the vivacity and verve of youthful ideas and feelings with the stark and sobering realities of life (Yu 35). In his works Yang makes stylistic references to and extends a nostalgic homage to varied salient periods and aspects of Chinese cinema (Yu 35). Yang’s photos extend symbolic answers to the questions pertaining to creativity and identity in the contemporary world. The strange thing is that Yang’s photos and films lack any discernible political

Frankenstein and Lord of the Flies Essay Example for Free

Frankenstein and Lord of the Flies Essay Frankenstein and Lord of the Flies were written in different centuries. Analyse the similarities and discuss the differences which you have found in these texts. You should pay particular attention to characterisation, style and theme. Mary Shelley wrote Frankenstein in the 18th Century. As there was no cinema or television available books were a widely accessible form of entertainment. Particularly fantastical texts like Dracula and Vathek were popular, books like these were not meant to be thought of as a portrayal of realism, this is why Frankenstein is very unbelievable. Frankenstein is set in a time when new science posed a threat to Christian beliefs, as society started to believe that man could be created. This all seemed very possible in the early 18th Century because Benjamin Franklin had previously invented a lightning conductor and in 1802 Galvani ran a current through a frogs legs and it produced a twitch. The thought of starting life with lightning terrified people because of the dangers it appeared to pose to endanger human life. William Golding published Lord of the Flies in 1954, nine years after the end of the Second World War. So there were still conflicts going on between Russia and America, Golding used the idea of continuous war and portrayed it onto the island. The text concerns a group of public school boys getting trapped on an island after their plane crashes; they all have traditional upbringings and attitudes. Other books, which had previously been written such as Swiss Family Robinson and Coral Island, featured a similar situation but with a happier ending, these types of books were all very unrealistic and fairytale like. William Golding wrote what he thought would really happen if anyone ever faced this situation. The two tribes that develop in Lord of the Flies (Jacks and Ralphs) represent Hitler and the Nazis against the allies (America, Great Britain etc). The Italians swapped sides during the war as the Nazis became weaker; Sam and Eric reflect this as they join Jacks tribe because Ralphs is less popular. Both books have many similarities and differences between them. The main similarity is that both books are about lines of civilisation being broken revealing the darker sides of peoples characters. The boys in Lord of the Flies are immediately, physically desolate after their plane crashes. Nobody knows where they are and there are no adults. In Shelleys book, the character Frankenstein chooses to be isolated as his work is more important to him than anything around him. One similarity between the two books are the characters Piggy and the creature. These two characters are both judged by their appearance. Piggy is shorter than the fair boy and very fat. He has asthma and thick spectacles. The creature has yellow skin and straight black lips, in both cases we can immediately tell that they are physically different. Even Frankenstein, the creatures creator dreaded to behold him. They both become isolated and victimised because other people see them as being different; this creates a feeling of sympathy towards both characters throughout the books. They also both have no parents as Piggys dads dead, and [his] mum, and the creature said: No father has watched my infant days, no mother had blessed me with smiles and caresses. The creature feels sadness and rejection and believes that having parents is important, this is also implicit in the case of Piggy, but the creature has never been loved by anyone so the feeling of depression is greater. It can be argued however that, in a way the creature has been loved as Frankenstein loved him while he was creating him. When he is brought to life the love he had previously received from Frankenstein ends. The difference between these two characters is that Piggys intelligence is threatening to the other boys as he has some sensible ideas that the boys do not wish to carry out. He says: Which is better- to have rules and agree, or to hunt and kill? The boys ignore him as they have already descended into tribalism at this point. Piggys intelligence is threatening because he has a very defined idea of what is right and wrong and he is a very moral person. The creatures intelligence is harmless as he only wishes to fit in. However, as the creature becomes more knowledgeable he discovered what a wretched outcast he was. He has no idea of what is right and wrong and only wants to fit in. The level of intelligence an individual has, whether it is a lot or a little can still make them isolated from others. From the start of Lord of the Flies we can tell that Piggy wants to fit in by the way he follows Ralph. Ralph disentangled himself cautiously and stole away through the branches. In a few seconds the fat boys grunts were behind him. He is last to put his hand up to vote for Ralph: Every hand outside the choir except Piggys was raised immediately. He hesitates because although he wants to vote for Ralph he does not want to be the only one who votes for him. He wants to fit in and not be the odd one out. It is implicit that Piggy was not very popular at school as They used to call [him] Piggy. This is why he follows Ralph in the way he does; he desperately tries to try and make friends as he feels depressed and sad about his previous school life. He is not very attractive; this is a reflection of how people perceive him. There are not just similarities between Piggy and the creature. Frankenstein and Ralph are also similar because although they are in different situations, they both have something they want to achieve. Ralph desperately wants to be rescued from the island. He constantly tries to keep the fire going as The fire is the main thing, because it is a signal to people to show that they are stranded. Frankensteins aim is to take science a step further by creating new life without using nature. They are both headstrong and both have will power to achieve what they want to. Unlike Frankenstein, Ralph sees reality as he acknowledges that if they do not try to get rescued they will die on the island. without the smoke signal well die here! Ralph is far more considerate than Frankenstein. Frankenstein does not consider the consequences of his actions and as a result of this he creates a disaster. He does not see reality as he becomes so determined to be the first person to create life. While Frankenstein is preoccupied with creating life, Ralph believes that preserving life is more important. Frankenstein can also be compared to Simon from Lord of the Flies. They are both symbolic of Christ. Simon passed food down to outstretched hands and Frankenstein stated that; food that I had killed, which after taking a small part, I always presented to those who had provided me. They are both kind and considerate and the way they give to others is much like the same way that Jesus did. Although Frankenstein has been isolated and anti social for a few years he is still amiable. Simon is surrounded by a lot of biblical images all through the book. The way that Simon appreciates the island and nature seems quite strange to the other boys. He is described as cracked and batty. In the same way Frankenstein gets remarks because he enjoys the structure of the human frame. and philosophy. Both Simon and Frankenstein are intransigent as they ignore any comments tackling their views. Frankenstein believes that: A new species would bless me as its creator would owe their being to me. He wants to be worshipped and idolised for creating life like God. Simon wants to appreciate his surroundings, which God as created. Frankenstein states that; No father could claim the gratitude of his child so completely as I should deserve theirs. He becomes arrogant and his ego begins to swell. He wants to totally change the way in which humans are brought to life and he becomes insatiably infatuated with this. Simon willingly accepts the beauty of nature and he sees things differently to other people, like the beast only being a fallen pilot (this shows more clarity of thought than the other boys). Unlike Frankenstein, Simons character is very vague, he is simply known as the boy who fainted towards the beginning of the book. He is also described as a vivid little boy. No one really understands him as he has more maturity to understand things than the other boys, but he does not have the vocabulary to express his views and feelings. Frankensteins character is not constant through the book. At first he is very unorthodox, as he does not consider the views or beliefs of anyone around him. Towards the end of the book he becomes remorseful as he realises that he has created a demoniacal corpse. When Simon died the clouds opened and let down the rain like a waterfall. This is pathetic fallacy as it reflects what is happening in the story. Simon is seen as God- like, and the storm and heavy rain is like Gods anger against the savage boys sin. It is as if they killed the good on the island and it cannot be justified or tolerated. After he is killed the language used is very calming; there was a trickle of water and no noise. This is ethereal, as if Simons body is being taken by angels up to heaven. The way Simons dead body moved out towards the open sea is very heavenly. When Simon sees the Lord of the Flies for the first time, Golding says: Even if he shut his eyes, the sows head still remained like an after- imageThey assured Simon that everything was a bad business. It is as if Simon is getting a vision from God; the sows head demonstrated how the hunting has got out of control. God is warning him that what is happening on the island cannot be accepted. After this has happened it is ironic that Simon is killed for being mistaken for the beast. The message given to him was right; the hunting on the island had become a bad business. The difference between the two books is that Frankenstein is a man of science and Simon is a man of spirit. In Frankenstein it is science against religion, where as in Lord of the Flies the human need to survive is put against society. Another character from Lord of the Flies who can be compared to Frankenstein is Jack. It is clear from the start that Jack will potentially be a threat from his appearance. He has red hair which signifies a fiery temper, and red is also used for warning signs, which indicate danger. Both Jack and Frankenstein become obsessive about certain things. Frankenstein becomes obsessed with creating the creature and Jack lets hunting become his obsession. Jack begins to bring up hunting in most conversations, he said: All the same- in the forest. I mean when youre hunting. He is the first to suggest that the choir form a group called the hunters and he is always the first to lead them out into the forest to go on a hunt he insists to the other boys that meat is important. Jack becomes excited by droppings that steamed he bends down to them as though he loved them. This is clearly not natural behaviour and these are definite signs that his obsession with hunting has gone too far. Frankenstein gets so engrossed with his work that he forgets about his family. He, like Jack, becomes disturbingly infatuated with his project as he does many inhumane things: [He]collected bones from charnel- houses and disturbed, with profane fingers, the tremendous secrets of the human frame. The word profane is important because it illustrates the way he shows disrespect for religion. In Lord of the Flies the other religion could be classed as Ralphs tribe. Jack does not consider the welfare of these boys and he becomes so obsessed with hunting that he forgets both his morals and the fact that the boys need to be rescued. While Jack is hunting The madness came into his eyes again. He has the urge to kill and his obsession has got so far out of control he is losing his sanity. However, these two characters are also very different because Jack has a cruel personality; he picks on the weaker boys. Piggy is usually his victim; he singles him out for the way he looks, he says, shut up fatty and you fat slug. He smacked Piggys head and he is also very sarcastic towards him: We mustnt let anything happen to Piggy, must we? His character is also very fierce; this becomes apparent from the language used. The way he slashed, slammed and snatched shows he is destructive. He acts like this so that the other boys become afraid of him and do not challenge his views; he feels powerful and dominant. He gains respect from the other boys by behaving like this: Jack looked round for understanding and found only respect. He regains the power which he lost from not being voted chief by behaving in this way, and he also feels he has control over the other boys. The boys do not always agree with him, they just followed him obediently because they are afraid of him. Jack is also like the creature because they both show their darker sides after being isolated. Jack believes he has the qualities to be leader because he can sing C sharp. When Ralph is voted leader, Jack immediately becomes isolated, and tension occurs between them as he constantly challenges Ralph to be leader. The creature becomes isolated because he is not socially accepted, as he looks different. His treacherous side shows as his level of intelligence increases. He begins to feel rage and revenge towards Frankenstein, in the same way Jack feels for Ralph. The creature says that: I declared ever-lasting war against the species, and more than all, against him who had formed me. The language used here is very strong; he shows feelings of hate towards Frankenstein because he enrolled him into a world of misery. Jack and the creature both develop feelings of hatred towards the ones who have ostracised them. Some of the words used to describe Jack and Frankenstein are animalistic. When Jack is hunting it is like he almost becomes an animal, he sniffs the air and comes trotting back. When Frankenstein gets angry he gnashed [his] teeth and ground them together. They do mot appear human as they are stripped of human characteristics such as conscience and morality. This suggests that they have evil natures. These evil natures can also be shown by the inhumane killings that occur in both books. Lord of the Flies and Frankenstein both feature violence, death and murder. In Frankenstein the creature becomes completely demoralized like Jack and Roger, the murders they commit are brutal, but the reader is more sympathetic for the creature because he has never been loved and however desperately he tried to find a friend he was always rejected. The boys in Lord of the Flies have been loved and brought up in a religious manner, so they have no excuse to kill. The boys deconstruction of their reality mirrors the creatures construction of reality. This can be shown when Simon is brutally torn apart, where as the monster is pieced together. Simon can also be related to the creature because he has a problem, which he cannot do anything about. Simon is epileptic and the creature is ugly and 8 foot tall. These are problems, which can stop them from being like other people. In Frankenstein the style in which the book is written is totally different than that of Lord of the Flies. There are three concentric layers, one within the other. The outer layer, which is the shortest, is Robert Waltons letters to his sister describing his voyage to the North Pole. In the next layer Frankenstein tells the story of how he created the monster and how he abandoned it in disgust. In the third layer the creature describes the struggle he has trying to fit in. There are also multiple storytellers in Frankenstein. In Lord of the Flies the book has a linear narrative as it reads from beginning to end, it is narrated entirely by the author. As Frankenstein is a gothic horror book, the murders do not come as much of a surprise to the reader, where as Lord of the Flies features innocent, young school boys committing brutal murders. So the shock value in Lord of the Flies is greater and indeed more horrific than that in Frankenstein. The books are also both written in a way so that the reader looses track of time. Many phrases are used in the text to imply that a lot of time has passed, like Two years had now nearly elapsed and Six years had elapsed. This reflects the insanity that develops in the characters. In Lord of the Flies there is a system of hierarchy, as there is only one place at the top Jack and Ralph constantly fight to be the highest so that they have power over the other boys. These boys are underneath Jack and Ralph in the hierarchy so they are not as powerful they are, this is why they follow one of them. Piggy is one of the weaker boys at the bottom; this is why he is victimised. In Frankenstein there is no system of hierarchy, everyone in the text is considered as equal. In both books there is a role reversal. In Lord of the Flies Ralph goes from being leader to an outcast who is left to survive on his own. Jacks hunting tribe eventually over powers Ralphs tribe who want to be rescued. This shows the immaturity of the boys as they forget their priorities. The role reversal in Frankenstein occurs between Frankenstein and the creature. Frankenstein has power over the creature while he is creating him, but when he disowns him; he is left to do what he likes. He becomes more powerful than Frankenstein (and indeed any human being) because of his sheer stature and his increased level of intelligence. Frankenstein is aware of the fact that he does not have any morals as he killed innocent children. The creature realises this: You are my creator, but I am your master; obey! Role reversals are used in the text to show that the goodness in a person does not always win. I have already discussed thematic issues within characterisation, but the main theme in both books is about the darkness of Mans soul. The evil side of man, which is inherent in everybody, can be brought out in different situations. The two books show this in different ways. Frankenstein involves an adult world confronted with many scientific changes. Lord of the Flies shows a world entirely populated by children who struggle to survive. However, in both books the same message is delivered; the notion of society breaks down when there is nothing to uphold it. This is explored through the themes of isolation, difference, anger, ambition and obsession. While the boys on the island are unwillingly taken out of society structure and the creature is forcefully thrust into it, the result is the same- the hidden darkness of mans soul is revealed.

The Tcp Service Model Information Technology Essay

The Tcp Service Model Information Technology Essay The transport service is implemented by a transport protocol used between two transport entities. The transport protocol have to deal with error control, sequencing, and flow control. UDP is a simple protocol and it has some niche uses, such as client-server interactions and multimedia, but for the most Internet applications, reliable, sequenced delivery is needed.UDP cannot provide this, so another protocol is required. It is called TCP and is the main workhouse of the internet. THE TCP SERVICE MODEL: TCP service is obtained by both the sender and receiver creating end points, called sockets. A socket may be used for multiple connections at the same time. All TCP connections are full duplex and point to point. Full duplex means that the traffic can go in both directions at the same time. Point-to-point connection contains exactly two end points. Another feature of the TCP service is URGENT DATA. When the urgent data are received at the destination. The receiving application is interrupted so it can stop whatever it was doing and read the data stream to find the urgent data. The start of the urgent data is not marked while the end is marked so the application knows when it is over. This scheme basically provides a crude signaling. THE TCP PROTOCOL: A key feature of TCP, and one which dominates the protocol design, is that every byte on a TCP connection has its own 32-bit sequencer. When the internet began, the lines between routers were mostly 56-kbps leased lines, so a host blasting away at full speed took over 1 week to cycle through the sequence numbers. Separate 32-bit sequence numbers are used for acknowledgements and for the window mechanism. The sending and receiving TCP entities exchange data in the form of segments. What should a segment have? 1.Each segment including the TCP header, must fit in the 65,515-bytes IP payload. 2.Each network has a maximum transfer unit, or MTU, and each segment must fit in the MTU. THE TCP SEGMENT HEADER: The following is the dissection of TCP header field by field. The Source port and Destination port fields identify the local end points of the connection. The source port number is of 16 bits and indentifies the sending host TSAP(client port number). The destination port number is of 16 bits and is used to identify the receiver host TSAP(server port number). The sequence number is of 32 bits size. Since TCP supports Byte-stream, in which each byte is numbered, big space is allocated for numbering i.e.(2 power 32=4096 million).With the help of these numbers only ,one can be able to differentiate the old delayed duplicate with fresh ones. The acknowledgement number is of 32 bits size. It specifies the next byte expected. The length of TCP header is of 4 bits size and indicates the number of rows. Next comes a 6-bit field that is UNUSED. The fact that this field has survived intact for over a quarter of a century is testimony to how well thought out TCP is. Lesser protocols would have needed it to fix bugs in the original design. Six 1-bit flags: 1. URG is set to 1 if the urgent flag pointer is in use. 2. The ACK bit is set to 1 to indicate that the acknowledgement number is valid. If ACK is 0, the segment does not contain an acknowledgement so the ACKNOWLEDGEMENT NUMBER is ignored. 3. The PSH bit indicates pushed data. 4. The RST bit is used to reset a connection that has become confused due to a host crash or some other reason. It is also used to reject an invalid segment or refuse an attempt to open a connection. In general, if you get a segment with the RST bit on, you have problem on your hands. 5. The SYN bit is Synchronization flag. It is used to establish connections. The connection request has SYN=1 and ACK=0 to indicate that the piggyback acknowledgement field is not in use. The connection reply does bear an acknowledgement, so it has SYN=1 and ACK=1. 6. The FIN bit is finish flag. It is used to release a connection. It specifies that the sender has no more data to transmit. CHECKSUM: A checksum is also provided for extra reliability. It checks the header, the data and the conceptual pseudoheader. When performing this computation, the TCP Checksum field is set to zero and the data field is padded out with an additional zero byte if its length is an odd number. PSEUDOHEADER: The pseudoheader contains the 32-bit IP addresses of the source and destination machines, the protocol number for TCP (6), and the byte count for the TCP segment. Including the pseudoheader in the TCP checksum computation helps detect misbelieved packets. TCP CONNECTION MANAGEMENT MODELING: The steps required to establish and release connections can be represented in a finite state machine with the 11 states listed below. In each state, certain events are legal .when a legal event happens, some action may be taken. If some other event happens, an error is reported. State Description CLOSED No connection is active or pending LISTEN The server is waiting for an incoming call SYN, RCVD A connection request has arrived: wait for ACK SYN SENT The application has started to open a connection ESTABLISH The normal data transfer state FIN WAIT 1 The application has said it is finished FIN WAIT 2 The other side has agreed to release TIMED WAIT Wait for all packets to die off CLOSING Both sides have tried to close simultaneously CLOSING WAIT The other side has initiated a release LAST ACK Wait for all packets to die off Each connection starts in the CLOSED state. When it performs either a passive open {LISTEN}, or an active open {CONNECT}, it leaves the state. If the other side does the opposite one, a connection is established and the state becomes ESTABLISHED. Connection release can be initiated by either side. The state returns to CLOSED, after it is completed. Description of the figure: The heavy solid line is the normal path for a client. The heavy dashed line is the normal path for a server. The light lines are unusual events. Each transition is labeled by the event causing it and the action resulting from it, separated by a slash. The event can either be a user à ¢Ãƒ ¢Ã¢â‚¬Å¡Ã‚ ¬initiated system call {CONNECT, LISTEN, SEND or CLOSE}, a segment arrival [SYN, FIN, ACK or RST}, or in one case, a timeout of twice the maximum packet lifetime. The action is the sending of a control segment {SYN, FIN or RST} or nothing, indicated by -.Comments is shown in parentheses. Figure: TCP connection management finite state machine. TCP TRANSMISSION POLICY: Windows Management in TCP is not directly tied to acknowledgements as it is in most data link protocols. If the sender transmits a 2048-byte segment that is correctly received, the receiver will acknowledge the segment. However, since it now has only 2048 bytes of buffer space (until the application removes some data from the buffer), it will advertise a window of 2048 starting at the next byte expected. The window management in TCP is shown in the following figure. Now the sender transmits another 2048 bytes, which are acknowledged, but the advertised window is 0. The sender must stop until the application process on the receiving host has removed some data from the buffer, at which time TCP can advertise a larger window. Senders are not required to transmit data as soon as they come in from the application. When the first 2 KB of data came in, TCP, knowing that it had a 4 KB window available, would have been completely correct in just buffering the data until another 2KB came in, to be able to transmit a segment with a 4KB payload. This freedom can be exploited to improve performance. On the following grounds the sender com still send segments upon receiving the win=0(window size) or (buffer available). When the window=0;the sender may not normally send segments, with two exceptions i)URGENT DATA MAY BE SENT To allow the user to kill the process running on the remote machine. ii)The sender may send a 1byte segment to make the receiver re-announce the next byte expected and window size. SILLY WINDOW SYNDROME: To transmit 1byte of message TCP overhead 20 bytes, IP are required.In other words just to transmit 1 byte, extra 40 Bytes are required. Whenever there is a 1 byte room available at the receiver buffer, the window update segment is sent. Since the receiver is requested for 1 byte the sender sends 1 byte which leads to the receiver buffer to be full over again. Asking for 1 Byte and sending 1 byte appears to be silly, hence the name silly window syndrome. To avoid Silly window syndrome, Nagle suggested NAGLES APPROACH: When the data comes to the sender 1 byte at a time, just send the first Byte and buffer, all the rest until the outstanding Byte is acknowledged. Then send all the buffered characters in one 1 TCP segment and start buffering again until they are all acknowledged. Nagles approach cannot be implemented for all applications. In particular, when as X-windows application is being run over the internet, mouse movements have to be sent to the remote computer. Gathering them and sending them in bursts makes the mouse cursor more erratically, which makes users dissatisfied. CLARKS ALGORITHM: This approach is to prevent the receiver from sending a window update for 1byte instead, it is forced to wait until it has a decent amount of space available and then advertise that. Nagles algorithm is with respect to sender and Clarkà ¢Ãƒ ¢Ã¢â‚¬Å¡Ã‚ ¬Ãƒ ¢Ã¢â‚¬Å¾Ã‚ ¢s algorithm with respect to solve Silly window syndrome. The overall goal is for the sender not to send small segments and the receiver not to ask for them. TCP CONGESTION CONTROL: When the load offered to any network is more than it can handle, congestion builds up. The Internet is no exception. Although network layer also tries to manage congestion, most of the heavy lifting is done by TCP because the real solution to congestion is to slow down the data rate. In theory, congestion can be dealt with by employing a principle borrowed from physics: the law of conservation of packets. The idea is to refrain from injecting a new packet into the network until an old one leaves.TCP attempts to achieve this goal by dynamically manipulating the window size. The first step in managing congestion is detecting it. A timeout caused by a lost packet could have been caused by either (1) noise on a transmission line or (2) packet discard at a congested router. Nowadays, packet loss due to transmission errors is relatively rare because most long-haul trunks are fiber. All the Internet TCP algorithms assume that timeouts are caused by congestion and monitor timeouts for signs of trouble the way miners watch their canaries. TCP TIMER MANAGEMENT: TCP uses multiple timers to do its work. The most important of these is the retransmission timer. When a segment is sent, a retransmission timer is started. If the segment is acknowledged before the timer expires, the timer is stopped. If, on the other hand, the timer goes off before the acknowledgement comes in, and the segment is retransmitted. A second timer is the persistence timer. It is designed to prevent the following deadlock. The receiver sends an acknowledgement with a window size of 0, telling the sender to wait.Later, the receiver updates the window, but the packet with the update is lost. Now both the sender and the receiver are waiting for each other to do something. When the persistence timer goes off, the sender transmits a probe to the receiver. The response to the probe gives the window size. If it is still zero, the persistence timer is set again and the cycle repeats. If it is nonzero, data can now be sent. A third timer that some implementations use is the keep alive timer. When a connection has been idle for a long time, the keep alive timer may go off to cause one side to check whether the other side is still here. If it fails to respond, the connection is terminated. This feature is controversial because it adds overhead and may terminate an otherwise healthy connection due to transient network partition. The last timer used on each TCP connection is the one used in the TIMED WAIT state while closing. It runs for twice the maximum packet lifetime to make sure that when a connection is closed; all packets created by it have died off.

Progeria - Hutchinson-Gilford Syndrome Essay -- genetic childhood dis

Progeria, otherwise known as Hutchinson-Gilford syndrome is an extremely rare, genetic childhood disorder with a reported incidence of about one in a million. Hutchinson reported the syndrome in 1886 when he found the first patient with Progeria. In 1904 Gilford described a second case of Progeria, thus creating the term to reflect the syndrome’s senile features. There are only about a hundred reported cases since the disorder has been discovered over a century ago. Currently, there are about thirty to forty known cases worldwide of Progeria. Affected children age up to seven times faster, have â€Å"plucked bird† appearance, many health problems and their lifespan is about thirteen years. There is neither known cause nor cure for this disease. It is usually first diagnosed based only on appearance and treatment is given for other conditions associated with the aging process rather the disease it self.   Ã‚  Ã‚  Ã‚  Ã‚  Effected children usually appear normal at birth. But within the first year of life severe changes come into accordance. These include: baldness and bodily hair loss, including eyebrows and eyelashes; â€Å"skin wrinkling accompanied by pigmented age spots; [†¦] unusually high pitched voice; undeveloped or underdeveloped sexual maturation; bone lesions, often resulting in fractures and hip dislocation† (Livneh, Antonak and Maron, 1995, p.434). Death usually occurs between the age of twelve and thirteen and it is due to â€Å"cardiovascular deterioration and generally includes arthrosclerosis, myocardial infraction and congestive heart failure (Livneh, Antonak and Maron, 1995, p.434).   Ã‚  Ã‚  Ã‚  Ã‚  The cause of Progeria is unknown as of yet. Because of its very rare nature, no definite cause can be pinpointed. However it is determined to be generic. In other words, it is thought that it is due to single mutated gene and each case might represent a single sporadic new mutation, which happens at conception. Therefore, as mentioned above, the diagnosis must be made solely on the appearance.   Ã‚  Ã‚  Ã‚  Ã‚  During my Internet research on this subject, I have found a real story of a thirteen-year-old girl, named Ashley. Her story captured my heart and I would like to use Ashley as an example in helping to understand the disease, its progress and how it affects people involved. Ashley was born on May 23, 1991 as what it seemed a normal and healthy baby girl. In July 1991 doctors disco... ...f the disease and death to help cope and adapt properly. General intervention recommendations can focus on; the child’s needs, other family members and the parents. Other intervention can address social issues such as spirituality, emotionality, coping modes and adaptation techniques. It is very hard to say to a parent of a dying child that any of the above might help a broken heart, however, professional help, understanding and loving environment and family might ease the hardships of loosing one’s child, sibling or a friend. Bibliography DeBusk, F.L. (1972). The Hutchinson-Gilford Progeria Syndrome. Jurnal of Pediatrics, 80, 697-724.  Ã‚  Ã‚  Ã‚  Ã‚   Livneh, Hanoch; Antonak, Richard F.; Maron, Sheldon. (1995). Progeria: Medical aspects, psycholosocial perspectives, and intervention guidelines. Death Studies, Vol .19(5), Sep-Oct 1995. pp. 433-452. Lori and Ashley’s Website. http://www.geocities.com/lori_and_ashley/. Visited on April 23, 2003. Mac Michael, R.A. (1996-2003) Hutchinson-Gilford Progeria Syndrome Network. http://www.hgps.net/about/. Visited on April 23, 2003. Progeria Research Foundation Inc. (1999) http://www.progeriaresearch.org/. Visited on May 2, 2002.

Knowledge Is Power: How To Buy A Computer :: essays research papers

Knowledge is Power: How To Buy A Computer Buying a personal computer can be as difficult as buying a car. No matter how much one investigates, how many dealers a person visits, and how much bargaining a person has done on the price, he still may not be really certain that he has gotten a good deal. There are good reasons for this uncertainty. Computers change at much faster rate than any other kind of product. A two-year-old car will always get a person where he wants to go, but a two-year-old computer may be completely inadequate for his needs. Also, the average person is not technically savvy enough to make an informed decision on the best processor to buy, the right size for a hard drive, or how much memory he or she really needs. Just because buying a computer can be confusing does not mean one should throw up his hands and put himself at the mercy of some salesman who may not know much more than he does. If one would follow a few basic guidelines, he could be assured of making a wise purchase decision. A computer has only one purpose; to run programs. Some programs require more computing power than others. In order to figure out how powerful a computer the consumer needs, therefore, a person must first determine which programs he wants to run. For many buyers, this creates a problem. They cannot buy a computer until they know what they want to do with it, but they cannot really know all of the uses there are for a computer until they own one. This problem is not as tough as it seems, however. The consumer should go to his local computer store, and look at the software that's available. Most programs explain their minimum hardware requirements right on the box. After looking at a few packages, it should be pretty clear to the consumer that any mid-range system will run 99% of the available software. A person should only need a top-of-the-line system for professional applications such as graphic design, video production, or engineering. Software tends to lag behind hardware, because it's written to reach the widest possible audience. A program that only works on the fastest Pentium Pro system has very limited sales potential, so most programs written in 1985 work just fine on a fast '486, or an entry-level Pentium system. More importantly, very few programs are optimized to take advantage of a Pentium's power. That means that even if the consumer pays a large premium for the fastest