Picture & musical instrument Essay Example for Free

Picture musical instrument Essay In this picture, it showcases a man playing a musical instrument called bagpipes which are prominent and widely used in Scotland and Ireland. Based on the composition of the image, the man is probably a musician from an average social class because his choice clothing is typically worn by commoners probably during the Renaissance period. Generally, this illustration depicts an ordinary event in a musician’s life in the early periods. There are many components in this image that can tell the story of this single picture. Lines, shapes, color, shading and proportions are the elements that give life to a portrait. For the hat, it is a simple head ornament made from a plain fabric. The color gray with touches of brown suggest that it must had been used numerous times. The color combination gives it an aged look making it in a way look stylish. More so, the flower with a hint of light purple and baby pink colored petals that is surrounded by a couple of olive green leaves provided a natural component in the musician’s head cover. At first, it may seem that the beautiful flower is wilting probably because of its downward position but if viewers would look closely, the loveliness of the flower resides on its perfect color combination which exudes harmony. Additionally, a two-toned colored feather is also present on the hat. It is seamlessly intertwined with the flower. The feather added life on this very minimal hat through the blending of the colors gold and cream. Furthermore, the soft brushstrokes on the strands of the feathers give a sense of movement. It contrasted the stiff but delicate position of the flower. Moreover, the feather and the flower can be considered as accents of the hat that showcases the creativity of the musician and his love for things that possess simple yet striking beauty. On another note, hats are usually are worn outdoors during sunny days to protect the face from the rays of the sun. But on this picture, the black background suggests that the time was around in the evening or he was probably indoors which justifies the dark backdrop. Meanwhile, the relatively large brim of the hat had cast a shadow on the musician’s face. In a way, his wrinkles were partly concealed from the viewers’ line of sight. But if it will be examined closely, the series of lines on the forehead and on the mouth area can be considered as the focal points of the facial features. These lines indicate that the musician is probably in his late 40s or early 50s. On the other hand, the eyes tell a different story. It is hard to tell whether the arch of the left eyebrow and the roundness of the eyes signify an emotion. He can either be feeling tired or impassive during his performance. The semi-closed mouth with ripples of lines along the cheek area also adds up to the anonymity of the musician’s emotions. No outstanding feature can really be distinguished making it hard to determine the prominent mood of the painting. Overall, the musician’s face was painted in details. The realistic skin-toned color of the face accented by a small blush of red on the cheeks, the protruding nose, big black eyes, arched eyebrows, nude lips and the fine facial lines made an accurate representation of a male’s physical appearance. Furthermore, the layers of wardrobe added more personality into the painting. The musician is wearing three layers of garments. In the first layer is a white collared long sleeve shirt which is covered by a red V-shaped long sleeve with a wide collar. The bottom of the red shirt is tightened by a garter producing sections of scrunched up fabrics. Also, it seems that there is a set of embroidery at the bottom of the red shirt which serves as the accents to this plain piece of clothing. It is evident from the collar line to the sleeves that the musician is wearing layered clothes. Also, the combination of red and white complements very well. The simplicity of the white is balanced off by the intensity of the red. The third layer is a coat which has the same color as the hat with a dominant grayish tone but with touches of light brown and white. Also, the utilization of dark colors gave a slimming effect on the musician which made him look less stocky. The lining of the coat has a similar shade with the red shirt but more on the orange side. Probably this was intended to give continuity and proper blending of the colors used in the outfit. The whole look of the clothes did not seem stiff because of the folds seen all over the layers of clothing. The folds were intricately added to add movement in order for the clothes to look like as if they were moving with the musician. More so, these folds or lines contrasted the heaviness of the coat which gave a fluid quality to the whole picture. An unusual element was present on the left sleeve of the coat. This object has a circular shape with three layers of different sizes ranging from small to large. At one end is a hole where a red ribbon was tied which was pinned into the coat. Most likely this object is a type of medal that represents the musician’s profession or his achievements or this could just be an ornament used for fashion purposes. Regardless of its function, the circular object adds a touch of splendor to the whole garment. Moreover, the layers of clothing suggest that the weather was cold and that the musician needed the three levels of shirts to provide heat in order for him to properly play his bagpipes. Meanwhile, the bagpipe was illustrated in a neutral mocha brown color. Four pipes of varying heights and appearance were strategically strewn all over the irregularly shaped leather bagpipe. Because of the different sizes of pipes, it gave an illusion of elevation giving some dimension to a flat medium. Also, the creases on the bagpipe added some movement and tension to the image. Furthermore, the hands of the musician holding the main pipe were precisely demonstrated. The veins, the nails and even the lines on the knuckles were accurately portrayed. The viewers can really notice these details which suggest that these hands have been through a lot of experience in playing musical instruments. Despite the rigidity of the details on the hands, the way the hands were positioned displayed softness and finesse which is a true mark of a talented musician.

Pre-activity Health Screening Case Study

Pre-activity Health Screening Case Study When an inactive person decides to participate in physical activity for the first time, there is a risk of possible major coronary problems. Sharkey and Gaskill (2007) state that inactive people who decide to start an activity are five times more at risk during vigorous exercise. The risk of engaging in exercise varies by the type of exercise and intensity, which a person participates in. This would mean the individual with cardiovascular problems is more at risk of having coronary problems. Sharkey and Gaskill (2007). As suggested by NHS Choices (n.d.) the risk can be dramatically reduced when completing a pre-activity health screening. Pre-activity health screening is a tool used mostly by exercise professionals. It refers to the process of collecting information about an individuals medical history and health status Heaney and Goodey (2012, p.136). This normally involves completion of a physical activity readiness questionnaire (PAR-Q). In addition physiological measures would also be done like height, weight, body mass index (BMI) body-fat percentage and waist-to-hip ratio (WHR). These are necessary to identify any further potential risks factors a person has relating to coronary heart disease(CHD)Heaney and Goody (2012) The American College of Sports Medicine (ACSM) cited in Heaney and Goodey (2012, p.139) recommended that people are categorized into low, medium and high-risk factors. For example, primary risk factors are those at the highest risk, this includes hypertension, cigarette smoking and those with high-cholesterol levels. Secondary risk factors are those classified as medium risk. For example, diabetes type one and two obesity and physical inactivity. Furthermore, the non-modifiable risk factors are classified as low risk. This would include men over 45 and women over 55, in addition to gender and a family history of heart disease. Another important factor is customer care, Sinka, I. (2012) suggested that if a fitness company wants to offer their services to a customer, then the customer needs to believe the service is worth taken part in. Not only does a pre-activity health screening ensure that the correct exercise programmes are offered, but also helps to understand and meet the customer needs. Furthermore, It is necessary for health and safety reasons. Completion of a pre-activity health screening demonstrates that health, and safety is always being considered. Similarly, as suggested by Jason Wamala pre active health screening reduces the risk against potential legal liability to the organization and employees. The open University (2008) Do Daisys results from the health screening physiological measurements fall into healthy ranges. The results show a number of risk factors that are likely to lead to the development of cardiovascular disease. Daisy is 55 years-old sources from ACSM, 2006; Woolf-May, (2006) cited in Heaney and Goodey (2012, p.139) implies that Daisy is at risk to coronary heart disease genetic or lifestyle factors cause plaque to be build-up in your arteries as you age. By the time youre middle-aged or older, enough plaque has built up to cause signs or symptoms. National heart and lung Institute (n.d.) Blood pressure tends to rise with age this could indicate part of the reason why Daisy has a resting blood pressure of 160/100 millimeters of mercury (mmHg), this indicates that Daisy has high blood pressure referred to as stage two hypertension. The Open University (2008) suggested that high blood pressure greater than 140/90 mmHg can dramatically increase your risk of developing cardiovascular disease such as heart attack or stroke. Marie Toms suggested that it may be worth retesting Daisy more than once The Open University (2008). National heart and lung Institute (n.d.) suggested that blood pressure did not stay the same throughout the day. It is a lot lower while you sleep and rise when you wake up. Blood pressure tends to rise when youre excited, nervous or active. If your blood pressure is above average most of the time, youre at risk to CHD. Daisys resting heart rate is ninety six beats per minute (bpm), the average bpm should be between sixty to one hundred bpm, NHS, (n.d.). However, Daisy is within the guidelines yet still at risk. NHS (n.d.) states that the resting heart rate is the number of beats in one minute when the body are at a complete resting state so the more your heart beats the more strain you put on your heart. Looking at Daisys body mass index (bmi) which is 29.01, this indicates that Daisy has an increased health risk. Using the guidelines from Sharkey and Gaskill (2007, p.242.), indicates that Daisy has a desirable BMI of between nineteen to twenty five. Sharkey and Gaskill (2007) also suggested that having a higher than desired BMI puts Daisy more at risk of atherosclerotic heart disease and hypertension. Since Daisy is inactive, and the results from the BMI indicate she is overweight NHS, (n.d.) suggested that these are 2 factors that have an increase risk of hypertension waist to hip ratio of 0.9 would indicate that Daisy has she is above average 0.86(study guide) this would indicate Daisy is more at risk In particular, heart disease, high blood pressure and diabetes develop when the inflammatory effects of that mass of fat hit your blood vessels Sharkey and Gaskill (2007) This would indicate why this individuals body fat percentage is so high, 25 for women is average so 33 percent is bad. The excess weight can put you at increased risk of heart disease, stroke and type two diabetes. To conclude Daisy needs to make some big life changes to avoid being at risk of CHD. For example, exercise regular to help her lose weight, lower her BMI and WHR. In addition to lowering her risk factors to CHD. Outline how physical activity could have a positive effect on Daisys health. Daisy is overweight and is bordering obesity with a BMI of 29.01, Sharkey and Gaskill (2007) suggested that obesity along with lack of activity has been suspected to have a link between coronary artery disease (CAD), hypertension and type two diabetes. For example, an increase level of blood lipids (fat) in the body increases insulin resistance. This means that the insulin-resistant cells cant take in glucose. Glucose levels then rise, which results in the release of more insulin, this in turn increases blood pressure causing possible hypertension and type two diabetes. Sharkey and Gaskill (2007) For example, a study was published by Morris and raffle (1954) cited in Sharkey and Gaskill (2007, p.17.) Showing a link between inactivity and CAD, the bus drivers were tested along with the conductors. The conductors were more active then the bus drivers and were shown to have a 30 percent lower risk of CAD then the bus drivers. It is also suggested by NHS (n.d.) that inactivity increases the risk of hypertension by thirty-five percent. The result published by (Morris and raffle) would suggest that physical activity would benefit Daisy and lower her risk to hypertension and CAD. In addition, People with very high blood pressure are three times more likely to experience CAD and four times more likely to get congestive heart failure then others. Sharkey and Gaskill (2007). Research has shown that physical activity can reduce blood pressure, in middle-aged and older women and Any inactive person engaging in exercise has a 60 percent lower risk of heart attack. Sharkey and Gaskill (2007). It is suggested that regular physical activity help prevent CHD by increasing the efficiency of the cardiovascular system, and example would be increased blood volume and decreased blood pressure. Daisy also runs her own business, which suggested Daisy may be under stress. Sharkey and Gaskill (2007) suggested that stress is associated with heart disease and hypertension. To conclude daisy needs to include some regular moderate activity may minimize the effects of stress and more importantly reduce the risk from cardiovascular disease. What legislation governs health and safety in a sports and fitness facility, and how might these relate to this incident? (250 words/13 marks) Health and safety requirements are supported by tort law. This is a wide area of law covering areas such as negligence and occupiers liability. For example, Heaney and Goody (2012) negligence in tort law concerns situations where a person suffers injuries due to carelessness, forgetfulness or thoughtlessness due to the results of another person. This would mean that person has breached their legal duty to take care. It would make them liable to that person for negligence. An example would be Susan the 14-year-old daughter of Alistair, the father and daughter are fully aware of the health clubs policy relating to no under-16s, and every member has to complete a gym induction and health screening. The father owes a duty of care to his daughter, as he should be competent to understand the policies that the gym has in place. In addition, Goodey, J (2008) p152) suggested that an occupier may not be liable for injuries to a child if accompanied by someone competent enough to look after them. Furthermore, statute law refers to the act of law made by parliament, this includes the health and safety at work act 1974 (HASWA 1974). For example, HASWA 1974) cited in Heaney and Goody (2012) 153 an employer must undertake all necessary measures to ensure visitors to their premises are not exposed to risks of health and safety. There is the management of health and safety at work regulations 1999 (MHSWR 1999) MHSWR 1999) cited in Heaney and Goody (2012) state that management running a health and safety facility are required to conduct a risk assessment to ensure the welfare of employees and visitors. Consequently, the fact Susan was still able to access the gym after claiming to be using the pool only may indicate that the employer has not taken all the necessary measures that fall under (HASWA 1974) and (MHSWR 1999). Discuss whether or not Alistair and his 14-year-old daughter Susan would have a case for a claim for negligence against the facility. There are many factors to consider that explain why Susan may not have a claim for negligence against the facility. One consideration may be that it falls within the occupiers liability act 1984 cited in Goodey, J (2008 p.151) states that a person who controls the premises is responsible for allowing or preventing access to visitors. It can be argued that Susan gained access to an unauthorized part to the facility. Therefore, the duty of care expected of the facilities owner was not met. This would be due to insufficient security measures to prevent unauthorized access to non gym members and people under the age of sixteen. However, Alistair is Susans father so already has a duty of care toward his child. Alistair is already a member of the gym, he has participated in an induction and health screening. Alistair is aware of the facilities policy that under sixteens are not allowed within the gym area therefore, Alistair has been a regular user with the facility. You would therefore expect Alistair to have a higher standard of competence. In addition, Susan is fourteen years old, it is thought that age fourteen they would have some awareness. (Heaney and Goody (2012) Susan went on to use a piece of gym equipment inappropriately, which highlights the cause of her injury. You could argue that the instructor supervising the gym at the time breached the duty of care for inadequate supervision. (Heaney and Goody (2012) However, the gym instructor would assume that all members in the gym at the time would have met the gym requirements and completed the induction and health screening. In addition, the instructors response to the accident was immediate and appropriate, as a result would indicate that the facility takes its duty of care seriously. To conclude the majority of Susan and Alistairs own negligence may have contributed to her injuries. Therefore, it would be suggested that Alistair and his 14-year-old daughter Susan would not have a case for negligence against the facility. Word count 1989

Fully Connected Mesh Topology Information Technology Essay

Fully Connected Mesh Topology Information Technology Essay These five labels describe how the devices in a network are interconnected rather than their physical arrangement. For example, having a star topology does not mean that all of the computers in the network must be placed physically around a hub in a star shape. A consideration when choosing a topology is the relative status of the devices be linked. Two relationships are possible: peer-to-peer, where the devices share the link equally, and primary-secondary, where one device controls traffic and the others must transmit through it. Ring and mesh topologies are more convenient for peer-to-peer transmission, while star and tree are more convenient for primary-secondary, bus topology is equally convenient for either. Mesh In a mesh topology, every device has a dedicated point-to-point link to every other device. The term dedicated means that the link carries traffic only between the two devices it connects. A fully connected mesh network therefore has n*(n l)/2 physical channels to link n devices. To accommodate that many links, every device on the network must have 7 input/output (I/O) ports. tifsTmp9.tif Figure (9) Fully Connected Mesh Topology A mesh offers several advantages over other network topologies. First, the use of dedicated links guarantees that each connection can carry its own data load, thus eliminating the traffic problems that can occur when links must be shared by multiple devices. Second, a mesh topology is robust. If one link becomes unusable, it does not incapacitate the entire system. Another advantage is privacy or security. When every message sent travels along dedicated line, only the intended recipient sees it. Physical boundaries prevent other users from gaining access to messages. Finally, point-to-point links make fault identification and fault isolation easy. Traffic can be routed to avoid links with suspected problems. This facility enables the network manager to discover the precise location of the fault and aids in finding its cause and solution. The main disadvantages of a mesh are related to the amount of cabling and the number of I/O ports required. First, because every device must be connected to ever other device, installation and reconfiguration are difficult. Second, the sheer bulk of the wiring can be greater than the available space (in walls, ceilings, or floors) can accommodate. And, finally, the hardware required connecting each link (I/O ports and cable can be prohibitively expensive). For these reasons a mesh topology is usually implemented in a limited fashionà ¢Ãƒ ¢Ã¢â‚¬Å¡Ã‚ ¬for example, as a backbone connecting the main computers of a hybrid network that can include several other topologies. Star In a star topology, each device has a dedicated point-to-point link only to a central controller, usually called a hub. The devices are not directly linked to each other. Unlike a mesh topology, a star topology does not allow direct traffic between devices. The controller acts as an exchange. If one device wants to send data to another, it sends the data to the controller, which then relays the data to the other connected device. HubtifsTmp10.tif Figure (10) Star topology A star topology is less expensive than a mesh topology. In a star, each device needs only one link and one I/O port to connect it to any number of others. This factor also makes it easy to install and reconfigure. Far less cabling needs to be housed, and additions, moves, and deletions involve only one connection: between that device and the hub. Other advantages include robustness. If one link fails, only that link is affected. All other links remain active. This factor also lends itself to easy fault identification and fault isolation. As long as the hub is working, it can be used to monitor link problems and bypass defective links. However, although a star requires far less cable than a mesh, each node must be linked to a central hub. For this reason more cabling is required in a star than in some other topologies (such as tree, ring, or bus). Tree A tree topology is a variation of a star. As in a star, nodes in a tree are linked to a central hub that controls the traffic to the network. However, not every device plugs directly into the central hub. The majority of devices connect to a secondary hub that in turn is connected to the central hub. The central hub in the tree is an active hub. An active hub contains a repeater, which is a hardware device that regenerates the received bit patterns before sending them out. Repeating strengthens trans- missions and increases the distance a signal can travel. tifsTmp11.tif Figure (11) Tree Topology The secondary hubs may be active or passive hubs. A passive hub provides a simple physical connection between the attached devices. The advantages and disadvantages of a tree topology are generally the same as those of a star. The addition of secondary hubs, however, brings two further advantages. First, it allows more devices to be attached to a single central hub and can therefore increase the distance a signal can travel between devices. Second, it allows the network to isolate and prioritize communications from different computers. For example, the computers attached to one secondary hub can be given priority over computers attached to another secondary hub. In this way, the network designers and operator can guarantee that time-sensitive data will not have to wait for access to the network. A good example of tree topology can be seen in cable TV technology where the main cable from the main office is divided into main branches and each branch is divided into smaller branches and so on. The hubs are used when a cable is divided. Bus The preceding examples all describe point-to-point configurations. A bus topology, on the other hand, is multipoint. One long cable acts as a backbone to link all the devices in the network. Nodes are connected to the bus cable by drop lines and taps. A drop line is a connection running between the device and the main cable. A tap is a connector that either splices into the main cable or punctures the sheathing of a cable to create a contact with the metallic core. As a signal travels along the backbone, some of its energy is transformed into heat. Therefore, it becomes weaker and weaker the farther it has to travel. For this reason there is a limit on the number of taps a bus can support and on the distance between those taps. Advantages of a bus topology include ease of installation. Backbone cable can be laid along the most efficient path, then connected to the nodes by drop lines of various lengths. In this way, a bus uses less cabling than mesh, star, or tree topologies. In a star, for example, four network devices in the same room require four lengths of cable reaching all the way to the hub. In a bus, this redundancy is eliminated. Only the backbone cable stretches through the entire facility. Each drop line has to reach only as far as the nearest point on the backbone. tifsTmp12.tif Figure (12) Bus Topology Disadvantages include difficult reconfiguration and fault isolation. A bus is usually designed to be optimally efficient at installation. It can therefore be difficult to add new devices. As mentioned above, signal reflection at the taps can cause degradation in quality. This degradation can be controlled by limiting the number and spacing of devices connected to a given length of cable. Adding new devices may therefore require modification or replacement of the backbone. In addition, a fault or break in the bus cable stops all transmission, even between devices on the same side of the problem. The damaged area reflects signals back in the direction of origin, creating noise in both directions. Ring In a ring topology, each device has a dedicated point-to-point line configuration only with the two devices on either side of it. A signal is passed along the ring in one direction, from device to device, until it reaches its destination. Each device in the ring incorporates a repeater. When a device receives a signal intended for another device, its repeater regenerates the bits and passes them along. A ring is relatively easy to install and reconfigure. Each device is linked only to its immediate neighbors (either physically or logically). To add or delete a device requires moving only two connections. The only constraints are media and traffic considerations (maximum ring length and number of devices). In addition, fault isolation is simplified. Generally in a ring, a signal is circulating at all times. If one device does not receive a signal within a specified period, it can issue an alarm. The alarm alerts the network operator to the problem and its location. However, unidirectional traffic can be a disadvantage. In a simple ring, a break in the ring (such as a disabled station) can disable the entire network. This weakness can be solved by using a dual ring or a switch capable of closing off the break. tifsTemp 13.a.tif Figure (13) Ring Topology OSI Model This model is based on a proposal developed by the International Standards Organization (ISO) as a first step toward international standardization of the protocols used in the various layers. The model is called the ISO-OSI (Open Systems Interconnection) Reference Model because it deals with connecting open systemsà ¢Ãƒ ¢Ã¢â‚¬Å¡Ã‚ ¬that is, systems that are open for communication with other systems. We will usually just call it the OSI model for short. The OSI model has seven layers. The principles that were applied to arrive at the seven layers are as follows 1. A layer should be created where a different level of abstraction is needed. 2. Each layer should perform a well-defined function. 3. The function of each layer should be chosen with an eye toward defining internationally standardized protocols. 4. The layer boundaries should be chosen to minimize the information flow across the interfaces. 5. The number of layers should be large enough that distinct functions need not be thrown together in the same layer out of necessity, and small enough that the architecture does not become unwieldy. Below we will discuss each layer of the model in turn, starting at the bottom layer. Note that the OSI model itself is not network architecture because it does not specify the exact services and protocols to be used in each layer. It just tells what each layer should do. However, ISO has also produced standards for all the layers, although these are not part of the reference model itself. Each one has been published as a separate international standard. tifsTmp2-a.tif Figure (16) The OSI Reference Model The Physical Layer The physical layer is concerned with transmitting raw bits over a communication channel. The design issues have to do with making sure that when one side sends a 1 bit, it is received by the other side as a 1 bit, not as a 0 bit. Typical questions here are how many volts should be used to represent a 1 and how many for a 0, how many microseconds a bit lasts, whether transmission may proceed simultaneously in both directions, how the initial connection is established and how it is torn down when both sides are finished, and how many pins the network connector has and what each pin is used for. The design issues here largely deal with mechanical, electrical, and procedural interfaces, and the physical transmission medium, which lies below the physical layer. The Data Link Layer The main task of the data link layer is to take a raw transmission facility and transform it into a line that appears free of undetected transmission errors to the network layer. It accomplishes this task by having the sender break the input data up into data frames (typically a few hundred or a few thousand bytes), transmit the frames sequentially, and process the acknowledgement frames sent back by the receiver. Since the physical layer merely accepts and transmits a stream of bits without any regard to meaning or structure, it is up to the data link layer to create and recognize frame boundaries. This can be accomplished by attaching special bit patterns to the beginning and end of the frame. If these bit patterns can accidentally occur in the data, special care must be taken to make sure these patterns are not incorrectly interpreted as frame delimiters. A noise burst on the line can destroy a frame completely. In this case, the data link layer software on the source machine can retransmit the frame. However, multiple transmissions of the same frame introduce the possibility of duplicate frames. A duplicate frame could be sent if the acknowledgement frame from the receiver back to the sender were lost. It is up to this layer to solve the problems caused by damaged, lost, and duplicate frames. The data link layer may offer several different service classes to the network layer, each of a different quality and with a different price. Another issue that arises in the data link layer (and most of the higher layers is well) is how to keep a fast transmitter from drowning a slow receiver in data. Some traffic regulation mechanism must be employed to let the transmitter know how much buffer space the receiver has at the moment. Frequently, this flow regulation and the error handling are integrated. If the line can be used to transmit data in both directions, this introduces a new complication that the data link layer software must deal with. The problem is that the acknowledgement frames for A to B traffic compete for the use of the line with data frames for the B to A traffic. Broadcast networks have an additional issue in the data link layer to control access to the shared channel. A special, sub layer of the data link layer, the medium access sub layer, deals with this problem. The Network Layer The network layer is concerned with controlling the operation of the subnet. A key design issue is determining how packets are routed from source to destination. Routes can be based on static tables that are wired into the network and rarely changed. They can also be determined at the start of each conversation, for example a terminal session. Finally, they can be highly dynamic, being determined anew for each packet, to reflect the current network load. If too many packets are present in the subnet at the same time, they will get in each others way, forming bottlenecks. The control of such congestion also belongs to the network layer. Since the operators of the subnet may well expect remuneration for their efforts, there is often some accounting function built into the network layer. At the very least, the software must count how many packets or each customer sends characters or bits, to produce billing information. When a packet crosses a national border, with different rates on each side, the accounting can become complicated. When a packet has to travel from one network to another to get to its destination, many problems can arise. The addressing used by the second network may be different from the first one. The second one may not accept the packet at all because it is too large. The protocols may differ, and so on. It is up to the network layer to overcome all these problems to allow heterogeneous networks to be interconnected. In broadcast networks, the routing problem is simple, so the network layer is often thin or even nonexistent. The Transport Layer The basic function of the transport layer is to accept data from the session layer, split it up into smaller units if need be, pass these to the network layer, and ensure that the pieces all arrive correctly at the other end. Furthermore, all this must be done efficiently, and in a way that isolates the upper layers from the inevitable changes in the hardware technology. Under normal conditions, the transport layer creates a distinct network connection for each transport connection required by the session layer. If the transport connection requires a high throughput, however, the transport layer might create multiple network connections, dividing the data among the network connections to improve throughput. On the other hand, if creating or maintaining a network connection is expensive, the transport layer might multiplex several transport connections onto the same network connection to reduce the cost. In all cases, the transport layer is required to make the multiplexing transparent to the session layer. The transport layer also determines what type of service to provide the session layer, and ultimately, the users of the network. The most popular type of transport connection is an error-free point-to-point channel that delivers messages or bytes in the order in which they were sent. However, other possible kinds of transport service are transport of isolated messages with no guarantee about the order of delivery, and broadcasting of messages to multiple destinations. The type of service is determined when the connection is established. The transport layer is a true end-to-end layer, from source to destination, in other words, a program on the source machine carries on a conversation with a similar program on the destination machine, using the message headers and control messages. In the lower layers, the protocols are between each machine and its immediate neighbors, and not by the ultimate source and destination machines, which may be separated by many routers. There is a difference between layers 1 through 3, which are chained, and layers 4 through 7, which are end-to-end. Many hosts are multi-programmed, which implies that multiple connections will be entering and leaving each host. Their needs to be some way to tell which message belong to which connection. The transport header is one place this information can be put. In addition to multiplexing several message streams onto one channel, the transport layer must take care of establishing and deleting connections across the network. This requires some kind of naming mechanism, so that a process on one machine has a way of describing with whom it wishes to converse. There must also be a mechanism to regulate the flow of information, so that a fast host cannot overrun a slow one. Such a mechanism is called flow control and plays a key role in the transport layer (also in other layers). Flow control between hosts is distinct from flow control between routers, although we will later see that similar principles apply to both. The Session Layer The session layer allows users on different machines to establish sessions between them. A session allows ordinary data transport, as does the transport layer, but it also provides enhanced services useful in some applications. A session might be used to allow a user to log into a remote timesharing system or to transfer a file between two machines. One of the services of the session layer is to manage dialogue control. Sessions can allow traffic to go in both directions at the same time, or in only one direction at a time. If traffic can only go one way at a time (analogous to a single railroad track), the session layer can help keep track of whose turn it is. A related session service is token management. For some protocols, it is essential that both sides do not attempt the same operation at the same time. To manage these activities, the session layer provides tokens that can be exchanged. Only the side holding the token may perform the critical operation. Another session service is synchronization. Consider the problems that might occur when trying to do a 2-hour file transfer between two machines with a 1-hour mean time between crashes. After each transfer was aborted, the whole transfer would have to start over again and would probably fail again the next time as well. To eliminate this problem, the session layer provides a way to insert checkpoints into the data stream, so that after a crash, only the data transferred after the last checkpoint have to be repeated. The Presentation Layer The presentation layer performs certain functions that are requested sufficiently often to warrant finding a general solution for them, rather than letting each user solve the problems. In particular, unlike all the lower layers, which are just interested in moving bits reliably from here to there, the presentation layer is concerned with the syntax and semantics of the information transmitted. A typical example of a presentation service is encoding data in a standard agreed upon way. Most user programs do not exchange random binary bit strings. They exchange things such as peoples names, dates, amounts of money, and invoices. These items are represented as character strings, integers, floating-point numbers, and data structures composed of several simpler items. Different computers have different codes for representing character strings, integers, and so on. In order to make it possible for computers with different representations to communicate, the data structures to be exchanged can be defined in an abstract way, along with a standard encoding to be used on the wire. The presentation layer manages these abstract data structures and converts from the representation used inside the computer to the network standard representation and back. The Application Layer The application layer contains a variety of protocols that are commonly needed. For example, there are hundreds of incompatible terminal types in the world. Consider, the plight of a full screen editor that is supposed to work over a network with many different terminal types, each with different screen layouts, escape sequences for inserting and deleting text, involving the cursor, etc. One way to solve this problem is to define an abstract network virtual terminal that editors and other programs can be written to deal with. To handle each terminal type, a piece of software must be written to map the functions of the network virtual terminal onto the real terminal. For example, when the editor moves the virtual terminals cursor to the upper left-hand corner of the screen, this software must issue the proper command sequence to the real terminal to get its cursor there too. All the virtual terminal software is in the application layer. Another application layer function is file transfer. Different file systems have different file naming conventions, different ways of representing text lines, and so on. Transferring a file between two different systems requires handling these and other incompatibilities. This work, too, belongs to the application layer, as do electronic mail, remote job entry, directory lookup, and various other general purpose and special-purpose facilities.

Invisible Man Essay: Invisible Mans Emergence -- Invisible Man Essays

Invisible Man's Emergence    During the epilogue of Invisible Man, the narrator's invisibility "placed [him] in a hole" (Ellison 572). This leads the reader to ask questions. Why did the narrator descend underground? Will he ever emerge?   By examining his reasons for going underground, comparing and contrasting his emergence versus his staying below, why he would want to emerge, and the importance of social responsibility, one will see that Invisible Man will clearly emerge (Parker ). Before one can determine whether or not the narrator will emerge from his proverbial hole, he must asses Invisible Man's reasons for going underground (Parker ). The literal reason for his initial descent was to escape two white men chasing after him. It is at this point that he says, "I felt myself plunge down, down; a long drop that ended upon a load of coal... and I lay in the black dark upon the black coal no longer running" (Ellison 565). If the reader then thinks back to the prologue, where Invisible Man introduces his living quarters, he sees some irony. During the prologue Invisible Man says, I doubt if there is a brighter spot in all New York...In my hole in the basement there are exactly 1,369 lights, I've wired the entire ceiling, every inch of it (Ellison 6-7). This extreme lighting contrasts with the darkness and blackness that is shown in the hole that he falls into. According to one critic, the brightness connotes an optimistic viewpoint that is new to Invisible Man (Parker ). He believed that "[his invisibility] placed [him] in a hole- or showed [him] the the [he] was in" (Ellison 572). He remained in the cellar to get away from "it all" (Ellison 573), and to contemplate his life and his grandfather's words- to po... ...ng] the foul air out" (Ellison 581). It is here that he wants to put his past behind him and move forward. He says: I'm shaking off the old skin and and I'll leave it here in the hole. I'm coming out, no less invisible without it, but coming out nevertheless. And i suppose it's damn well time (Ellison 581). Works Cited and Consulted Bellow, Saul. "Man Underground" Review of Ralph Ellison's Invisible Man. Commentary. June 1952. 1st December 2001 Available: http://www.english.upeen.edu/~afilreis /50s/bellow-on-ellison.html Ellison, Ralph. Invisible Man. New York: The Modern Library, 1994. O'Meally, Robert, ed. New Essays on Invisible Man. Cambridge; New York: Cambridge University Press, 1988. Parker, Robert Dale "Black Identity and the Marketplace of Masculinity" 30 January 2002 Available: http://www.english.cmu.edu/~ Parker/50s/ellison.htm Invisible Man Essay: Invisible Man's Emergence -- Invisible Man Essays Invisible Man's Emergence    During the epilogue of Invisible Man, the narrator's invisibility "placed [him] in a hole" (Ellison 572). This leads the reader to ask questions. Why did the narrator descend underground? Will he ever emerge?   By examining his reasons for going underground, comparing and contrasting his emergence versus his staying below, why he would want to emerge, and the importance of social responsibility, one will see that Invisible Man will clearly emerge (Parker ). Before one can determine whether or not the narrator will emerge from his proverbial hole, he must asses Invisible Man's reasons for going underground (Parker ). The literal reason for his initial descent was to escape two white men chasing after him. It is at this point that he says, "I felt myself plunge down, down; a long drop that ended upon a load of coal... and I lay in the black dark upon the black coal no longer running" (Ellison 565). If the reader then thinks back to the prologue, where Invisible Man introduces his living quarters, he sees some irony. During the prologue Invisible Man says, I doubt if there is a brighter spot in all New York...In my hole in the basement there are exactly 1,369 lights, I've wired the entire ceiling, every inch of it (Ellison 6-7). This extreme lighting contrasts with the darkness and blackness that is shown in the hole that he falls into. According to one critic, the brightness connotes an optimistic viewpoint that is new to Invisible Man (Parker ). He believed that "[his invisibility] placed [him] in a hole- or showed [him] the the [he] was in" (Ellison 572). He remained in the cellar to get away from "it all" (Ellison 573), and to contemplate his life and his grandfather's words- to po... ...ng] the foul air out" (Ellison 581). It is here that he wants to put his past behind him and move forward. He says: I'm shaking off the old skin and and I'll leave it here in the hole. I'm coming out, no less invisible without it, but coming out nevertheless. And i suppose it's damn well time (Ellison 581). Works Cited and Consulted Bellow, Saul. "Man Underground" Review of Ralph Ellison's Invisible Man. Commentary. June 1952. 1st December 2001 Available: http://www.english.upeen.edu/~afilreis /50s/bellow-on-ellison.html Ellison, Ralph. Invisible Man. New York: The Modern Library, 1994. O'Meally, Robert, ed. New Essays on Invisible Man. Cambridge; New York: Cambridge University Press, 1988. Parker, Robert Dale "Black Identity and the Marketplace of Masculinity" 30 January 2002 Available: http://www.english.cmu.edu/~ Parker/50s/ellison.htm

The Debate Regarding the Freedmans Bureau Essay -- African American B

The Debate Regarding the Freedman's Bureau Historians and political theorists have delineated the concept of equality into two categories: the competitive individualist notion of equality of process and the egalitarian ideal of equality of results. The former is concerned with providing a level playing field for all, while the latter focuses on a just distribution resulting from the process. Richard Ellis, in his book American Political Cultures, challenges the Hartzian thesis that historically Americans favored equality of process over equality of results, making them competitive individualists. Ellis argues that â€Å"what is exceptional about America is not that it lacked a results-oriented vision of equality but that those who favored equalizing results believed that equal process was a sufficient condition for realizing equal results† (Ellis 1993: 44). In other words, the egalitarian spirit was not absent from American history, but Americans believed that justice would best be served through competition. Ellis is correct in making this fine distinction, yet it is important to note that historical evidence suggests that some factions clearly emphasized equality of results regardless of equality of process. In The Souls of Black Folk, W.E.B. Du Bois’ recounting of the political debate regarding the Freedman’s Bureau, clearly highlights this ideological difference. Du Bois poignantly captures the necessity for a legal equalizing measure in his description of the tragedy of slavery and the ragged, conflicted nature of the black consciousness that resulted. He writes, â€Å"the facing of so vast a prejudice could not but bring the inevitable self-questioning, self-disparagement, and lowering of ideals which ever accompany repressio... ...ows, that given dire circumstances, Americans indeed turn to measures to ensure equality of results rather than relying on equality of processes. Of course, suffrage left much to be desired for African American equality. Jim Crow laws and other forms of racism continued to plague American society for many decades to follow. Nonetheless, the legacy of the Bureau remains an important part of American political history. It may require extreme instances of human misery, tragedy, and utter inequality (such as the institution of slavery) to highlight a push for equality of results regardless of the processes. This egalitarian ideology clearly is evident in post-Civil War American legislation. Works Cited: Du Bois, W.E.B. 1997. The Souls of Black Folk. Boston: Bedford Books. Ellis, Richard. 1993. American Political Cultures, New York: Oxford University Press.

Lost at the Fair

Lost at the Fair Every august the family would load up and head to the big fair in Leitchfield. Always excited to get there and head to the rides while dad went to the tractor pull. It was always a great experience until the year 1993. Mom was taking me and my brothers to the rides. We had been to several was having an absolute blast. Then my world froze and I was scared for my life. We were coming out of the fun house my brothers were ahead of me and suddenly I couldn’t find them.I looked in front of me then behind me no where’s around I decided to take the exit and go to my mom. I thought she’d be right around the corner, but when I rounded it she was no where’s insight. I started walking around scared and crying I couldn't find my mom no where’s. Suddenly this woman came to me. I wasn’t sure if she was going to help me or take me she was just a stranger. Luckily this was a very sweet woman who took me to the announcer box; she was going to help me get back to my mom.The announcer asked me my mom’s names and they hollered several times I was worried she couldn’t hear them and what was I going to do. Four years old in the middle of a fair with hundreds of people. Finally my aunt came to the announcer box after they assured she was my aunt they released me to her. Then out of nowhere I heard my mom’s voice hollering for me. Both scared and crying we were reunited and thankful I was safe. I learned a valuable lesson that day and I wasn’t going to wonder off anymore.

The Historical Biography of Martin Luther

It is obviously important to note that society has evolved and that the issues of the sixteenth century although dictated by time are not all that different than what our schools face today. There may not have been a separation of church and state but there was a need for educational reformation. â€Å"It is sometimes forgotten that the Reformation was as much concerned with school as it was with church and home. Appreciating the role of education in directing church and society back to the source of the Christian faith, the reformers were committed to the schooling of the young. (Faber, 1998) There is no doubt that Martin Luther appreciated the structured approach of schools since one of his first official acts as a reformer was an attempt to convert existing monasteries schools. â€Å"For Luther, of course, education was grounded in the study of Scripture, a study that was to take place both within homes and schools. Committed by the First Amendment to separation of church and state and to freedom of religious expression, pluralistic America of the twenty- first century is very different from Luther†s Germany of the sixteenth century. (Harran, 2004) Many of the underlying foundation of the modern public schools systems around the world owe a great deal to the sixteenth century Reformation and Martin Luther. â€Å"In home, school, church, and community, fostering that awareness and understanding is the purpose of education and the responsibility of educators. No challenge is more urgent than empowering young people courageously to step into the stream of human events, refusing to stand upon the shore as bystanders. (Harran, 2004) Who better to use as a scholar for this particular work. I believe that Martin Luther would agree with the notion that our graduates should not only have a desire for collaboration, but should also strive to develop the bonds within a school†s collaborative learning environment. Luther lived in a time where only the wealthy or well connected received an education. This class isolationism went against the philosophies of today where diversity and interdependent social cultures strive to exist. In opposition to those who saw education as the privilege of only a few, Luther argued vociferously for compulsory education for all, recognizing the value of each individual before God. In an age in which only a few could afford to attend school and women received little if any education, Luther eloquently argued for expanding educational opportunities. † (Harran, 2004) Luther believed that a universal educational opportunity offered more to society and that mass education would be more advantageous because of the fact that it offered more collaborative opportunities. In the words of Martin Luther, â€Å"My dear sirs, if we have to spend such large sums every year on guns, roads, bridges, dams and countless similar items to insure the temporal peace and prosperity of a city, why should not much more be devoted to the poor neglected youth? † (Harran, 2004) Luther believed that society would benefit if more individuals were given the opportunity to improve themselves and he also seemed to understand that this process should include more collaborative educational methods. I also agree with the idea of collaborative educational methods and goals. I also believe that as teachers, we should promote the idea of students working together so they can learn from one another and at the same time extend their willingness and ability to interact and learning outside of the classroom. Today†s kids need PDA†s and other technology just to keep up with their own and friend†s busy schedules. Between commuting, extra curricular activities and homework, students may find that it is hard to coordinate with their peers. That is why we as teachers must create scenarios that promote togetherness through properly applying classroom settings, the use of technology and sound planning to eliminate the barriers of collaboration. It is a teachers responsibility to create an atmosphere that provides a comfortable setting for contribution by all, enable collaboration without regard to time or place and to help students learn from each other no matter what their diverse backgrounds might be. Luther was an advocate of a well conceived educational process. Writing in times far different than ours, Luther underscored the importance of a curriculum that truly engages young people and that inspires them to a genuine love of learning in all its many forms. † (Harran, 2004) This atmosphere can only occur if the teachers and administrative entities support critical self-reflection by the teachers. Teachers can only provide curriculums that engage if they themselves are up to date in their personal reflections and educations. I also agree with the fact that self awareness, professional development and personal achievement by teachers are areas that are critical to the success of the entire educational process. Professional development for example can be considered important in the realm of critical self-reflection because it is a vital piece of the teaching puzzle. Teachers who evaluate their needs and performance can use professional development opportunities to stay current with the new or available practices in teaching, learning and presentation. Consider that a large number of math teachers simply place far too much influence and credence on outdated text books and techniques. â€Å"Even while educators work to reduce the dominance of text-based learning in mathematics classrooms, publishers and teachers need to explore new modes of publication that will enable good innovative ideas to enter expeditiously into typical classroom practice. † (National Research Council 1989, p. 67) Self reflection will provide opportunities to change. Martin Luther and his reformers were the most social conscious individuals of their time. The reformations that he promoted were basically social justice reformations. Luther believed that the existing class system was not fair and that all classes should receive the opportunity for an education. â€Å"Not only would the state benefit from a reformed education, but also – and especially – the church. † (Faber, 1998) In the sixteenth century, those who could not read or write were forced to learn their religious scriptures form the religiously factions thus putting the poor and uneducated at a distinct disadvantage. Luther promoted that all individuals be educated and therefore eliminate those social injustices. Similar to the unfair class separation of Luther†s times, I believe we must address the social injustices of our times. â€Å"Schools in the United States face a multiplicity of challenges, from gaining adequate funds to hiring well-qualified and dedicated teachers to meeting the ever-increasing obligations of state-mandated testing to determining policy about such complex issues as bi-lingual education. † (Harran, 2004) We today face the distinction of having schools in poor urban areas that have no books, are literally unsafe, have no clean running water and certainly few to no good teachers while less than a mile down there could be an affluent school with a plethora of extras and well manicured lawns. Social justice always boils down to the haves and the have not†s. Consider the differentiation with the technology have line today. Schools that can afford new technology have it in abundance and every child has access to the internet and other educational tools. But, in our urban communities there are whole high schools that may only have five or six computers and those are for administrative applications. Today we are more adept at working with the special needs of race, ethnicity, class, cultural and linguistic diversity, religion, gender, sexuality and special needs. In Martin Luther†s sixteenth century, diversity was focused more on the differences between rich and poor and religious preference was a one way street. So when he wrote or worked to reform the system, he was trying to incorporate those who were considered to be the minorities of their time. Yet, whether the differences were color or religion is not relevant. The key is that there was a need for reform with the existing process just like we have a need for change in our modern day educational process. â€Å"The need for educational reform was urgent at the beginning of the sixteenth century. At that time there existed no school system as such, and teaching was often limited to the children of wealthy merchants and city rulers. In many places the Roman Catholic church supervised the training of the youth in monasteries, cloisters, and other church-run institutions. But these were falling into disrepute and disrepair, as the populace reacted against the corruption and abuses among the clergy. † (Faber, 1998) Today, research covering the effects of diversity in the classroom show how and why effective teaching can be linked to the ability of instructors to incorporate diversity into their classrooms. These studies repeatedly show that there is a direct correlation between a child†s attitude towards his or her race and ethnic grouping and other cultural groups from as early as the preschool years. In other words, young children develop their stereotypes in the classroom or in the home environment at very early ages. Teachers can therefore help reduce or hopefully even eliminate negative stereotypes by being diversity conscious themselves. Through the use of culturally sensitive class initiatives for example, teachers have an opportunity to establish more positive examples for their students. â€Å"Researchers agree that new models of professional development are needed, and that such models must include a focus on the development of local cultures of interest if they are to be sustainable. (Swan, Vargas, & Holmes, 2004) In conclusion, this paper was on Martin Luther and also my interpretations of his views on the treatise of scholarship and education. From Luther†s point of view, this report attempted to propose possible reforms in the area of curriculum. The report was formatted in the form of an action plan that articulated my personal philosophies of teaching and identified with Martin Luther as my selected scholar. Issues addressed were the educational and conceptual frameworks of collaboration, social justice, diversity and critical self-reflection. Obviously Martin Luther appreciated the structured approach of schools since one of his first official acts as a reformer was to convert existing monasteries into schools. This may even be the underlying foundation of all modern public schools systems around the world. Who could be a better scholar for this particular project. â€Å"There is no denying the huge gap between the sixteenth century and the twenty- first. Luther†s Germany was overwhelmingly Christian; he could look to the state to further the agenda of Christian education, although he insisted that the responsibility for education was not solely, or even primarily, the responsibility of government. We live in a very different world from that of Luther. The United States is rich in cultural and religious diversity, and, from an early age, children experience that diversity and multiplicity of religious traditions and values in school and community. † (Harran, 2004)