WAN devices Essay Example for Free

WAN devices Essay Switches are very similar to hubs with the exception of containing the ability to read the packets received. This means that the device gets the packets, reads them and only forwards them to the appropriate attached device. Because switches can read the packets instead of just sending them on to all devices, it means they operate at the data link layer, layer 2. Repeaters A repeater is a simple device that boosts the signal so that it can travel much greater distances or avoid obstacles. They operate at Layer 1 of the OSI Model. Hubs A hub is simply a device that connects parts of LANs together. They are multiport devices and copy the data received from one port onto the other ports. Hubs operate at the physical layer (level 1) as they operate by using simple physical transmissions to send data from one device to the next. Hubs only use bits to send the data and cannot understand anything above bits on the OSI model. Bridges Bridges and Routers are quite similar they both direct traffic between two devices. A bridge will connect hardware together using hardware assigned MAC addresses. Bridges are a layer two device. This means that bridges cannot determine the type of network that theyre running on. Routers Routers, like hubs and switches, connect together multiple networks. Routers use headers and forwarding tables to create and send packets to determine the path through the networks and this means they operate at level 3, the network layer. Gateways Gateways are used to interface with another network that uses different protocols. This allows two different systems using two different protocols to work with each other. Gateways operate at all levels of the OSI model. Gateways can handle what can access the network and what cannot and helps to control the applications that require networks to run. LAN Connectivity Local Area Networks are very easily constructed with the use of these devices. LANs are quite easily created using; routers; hubs, switches, bridges; gateways and repeaters as well as UTP wiring. The network consists of many devices. Depending on the purpose of the network; the devices attached to it will be different. A network that needs an external connection will include a router as this makes external access possible but Local Area Networks could use hubs, switches or bridges to connect parts of the network together. Gateways are also a possibility when connecting devices together that dont necessarily know how to interface with each other. Connectivity Uses Range Main Points Copper Twisted Pair Cable Short to medium distance networks 100 meters. Â  Can have problems with interference. Â  Cheaper than newer types of technology. Â  Main different types used for many varied uses. Created when two conductors are twisted together. Â  More twists desirable less interference. Coaxial Cable TV, broadband and radio Between 750ft and 1500ft dependant on cable type Uses insulation to carry the signal with the least amount of interference. A lot of research has gone into creating the most effective systems those with space carry the signal better. Â  Extremely cheap and easily available. Â  Two types rigid and flexible. Fibre Optic Cable TV, broadband and radio 160km when used with amplifiers. Â  Light is sent down an optical cable. Â  Created in the 1980s. Â  Replacing older systems. Â  Much more reliable less chance of interference. Â  Expensive. Wireless Ethernet Sharing a connection or resources across a short distance network 30 meters. Standards known as 802. 11. G and B are the most common. Â  Requires a wireless router to project the signal to a computer or other electronic device. Satellite The internet and WWW. Worldwide signal sent across many satellites. Bandwidth of 34 Mbit/s* Ability to send large amounts of information across the world. Microwave Internet, mobile phones, networks, TV and many other uses. Line of sight unless amplification is used. Â  Transmitter and receiver need to line up. Â  Used in many ways 802. 11g is one example of a microwave. Importance to Small Office, Medium Business and Large Company on a scale of 1 to 3. Small Office Medium Organisation Large Organisation Speed 2 2 3 Size 3 2 1 Cost 3 3 2 Connectivity 1 2 3 Selecting Equipment Choosing any type of network equipment is a very important decision. Each and every organisation and office will be unique in its requirements. Speed Speed is a necessity for some offices; usually those that rely heavily on the network for day to day activities. The more computers that are connected the network, the more bandwidth the equipment must be capable of providing. A single slow device on the network is going to slow down everything as networks are only capable of running at the speed of their slowest device so ensuring that all devices are capable of carrying the correct speeds. Other networks are not going to need high speeds such as those that only connect just a few computers together, or those that will only connect to the network occasionally. Size The size of a device is not necessarily all that important for most businesses if they have the room to keep it. For a medium to large business, finding space to place your hardware is unlikely to be a major problem. Smaller businesses will usually have less space to place their hardware, particular the type of safe and secure space that is required by such important devices. Finding a device that is small enough to be stored but still fulfils other requirements is required. Cost The cost of a device is not going to be all that important to larger businesses; spending a lot of money on a useful device seems only natural. But when spending the vast majority of a networks budget on a single device, cost definitely becomes a factor. It must be the right device and it must do the job its required to do but it should also be at the right cost to the business. Connectivity Connectivity is heavily dependent on the number of computers that are being connected as well as what services the network is trying to provide and how the devices are going to be connected. The device that is eventually chosen must be a combination of the most important needs of the network. Placing a value on each of these factors should suggest the device that is needed.

Neural Network Architecture Construction

Neural Network Architecture Construction Introduction This article is going to discuss neural network construction from a different perspective than is usual in conventional approaches. This approach, which will be referred to as Neural Architecture, is intended to explore construction of neural networks using neurons as explicit building blocks rather than anonymous elements trained en mass. Simple Python programs will be used to demonstrate the concept for simple boolean logic functions. The approach of this article is intentionally named Neural Architecture because it is meant to parallel the way in which a traditional architect systematically constructs a fine building: by developing well-known patterns of construction elements, which may be re-used to create ever more sophisticated structures. The conventional approach to neural network development is to define a network as consisting of a few layers in a multilayer-perceptron type of topology with an input layer, output layer, and one or two hidden layers. Then a training algorithm such as backpropagation is applied to develop the interconnection weights. Sometimes a more sophisticated approach is taken such as using a cascade or recurrent topology but for all intents and purposes, the end result is a standard topology of a few highly-connected layers. This approach was a major breakthrough in the field because it led some people to start thinking outside the box of symbolic reasoning that dominated Artificial In telligence at the time. It has also been successfully used in a variety of pattern recognition and control applications that are not effectively handled by other AI paradigms. However, these applications would not generally be considered to represent higher levels of intelligence or cognitive processing. For example, suppose a neural network is developed that can successfully recognize human faces under a variety of conditions. This is a highly useful application and well within the realm of conventional neural networks. However, that is where the capability of the network leaves offat recognizing the facial image. Aside from generalizing facial features, it can offer nothing more in terms of reasoning about those facial features. Further, it is asserted that the standard approach to neural network development is not suitable for realizing these higher levels of intelligence. One of the fundamental problems is the limited manner in which we approach the neural architecture. To illustrate this problem, we will return to the building architecture analogy. In this way, our standard approach to neural architecture can be likened to designing a building using bricks. An architect who always thinks in terms of bricks will not likely progress beyond a certain level of sophistication, because as a component, a brick only offers one purpose: to support other bricks. Instead, an architecture progressively develops more sophisticated, proven structures based on the brick (or other primitive components) which can be re-used to develop higher-level components. A house is conceived, not in terms of bricks and wood, but rather in terms of walls, doors, and rooms. A sophisticated architect might even find these components mundane and instead think in more abstract terms of spaces, energy and flow of human traffic. This is the notion of patterns, and in fact these (architectural) patterns were exactly the inspiration for the field of software patterns. The same thinking can be applied to neural networks: a neuron by itself only serves the function of exciting other neurons. And conventional neural net learning algorithms are geared toward categorization or other mapping operations. As a proponent of neural networks, one believes that arbitrarily complex intelligence processes can be realized, and we have the human brain as pretty convincing support of that belief. However, to continue progress in this direction, it is likely that we have to develop more sophisticated abilities as neural architects and develop useful, proven neural patterns similar to the way that building architects have done over time, and in the way software architects are now doing. Enough philosophy we will now be taking a fresh look at how patterns can be constructed starting with simple neural elements, and specifically we will start with boolean logic elements. Architecting using boolean logic does not immediately offer an advantage over using regular logic gates, but illustrates how crisp logic or symbolic elements can arise from fuzzy neural processing elements. It will also provide a conceptual foundation for future articles. Neural networks Neural network: information processing paradigm inspired by biological nervous systems, such as our brain Structure: large number of highly interconnected processing elements (neurons) working together Like people, they learn from experience. Neural networks are configured for a specific application, such as pattern recognition or data classification, through a learning process In a biological system, learning involves adjustments to the synaptic connections between neurons. The first step in the architecture process is to define the primitive building block, and if you havent fallen asleep at this point, you have no doubt figured out that this will be a neuron. The neuron model we will use is a version of the tried-and-true model used for software neural networks, also known as the perceptron. As illustrated in , the perceptron has multiple inputs and one output. The mathematical model of the perceptron is given by: a = squash(ÃŽ £(iiwi)) where: is input i to the perceptron is the weight for input i is the activation (output) and squash(x) = { 1 if x >threshold 0 otherwise The nature of the perceptron has been discussed many times elsewhere, including in Matthews, so we wont dwell on it here. But basically, the perceptron calculates a weighted sum of the inputs and then subjects it to a nonlinear squashing functionin our case, this is a simple threshold operation. The nonlinear threshold operation is part of what makes a neural net exhibit interesting behavior. Otherwise it would amount to matrix operations. Nature of the game Now that we have the model for a basic neuron defined, we can now proceed to define basic logic gates by simply working out two things: the weight values the threshold For our discussion we will assume that weights can be positive (excitory) or negative (inhibitory) and be in the range between -1 and 1. The threshold will also be assumed to be in the range -1 to 1. If we cast this in terms of signals, then it equates to the requirement that both inputs have to be sufficiently high to produce an output. So, we will set our threshold to a high value of 0.8. Next we will set the weights for the two inputs at 0.5 each. If one input is one (=1) then the neuron activation (output) will be given by a = squash( 1 * 0.5 + 0 * 0.5) = squash( 0.5 ) = 0 since 0.5

Descartes philosophy Essay -- essays research papers

Descartes’ â€Å"evil genius scenario† provides the possibility for the existence of an evil genius that is in control of our world in place on an omnipotent god. By in control, I mean that he would in some magical way compose our lives by his own will, thus making any certain knowledge about material objects impossible. This scenario presents some real questions with Descartes’ argument because it basically completely rules out the possibility of any god.   Ã‚  Ã‚  Ã‚  Ã‚  We are imagining that Dr. Spiritus has invaded a small rural hospital and has stolen the brains of several babies. He places the brains in a large vat, provides them with the essential nutrients as well as hooking them up to electrodes that feed the false images into their minds. These impulses that the doctor would distribute at his own will would make the babies brains think that they are actually in their bodies living their lives as normal people. The doctor would provide all the necessary experiences such as childhood, school, first love and etc. However since Dr. Spiritus is an evil genius, he feels it necessary to feed these minds the stimuli of pain, suffering, and disaster.   Ã‚  Ã‚  Ã‚  Ã‚  The first question that arises is if it is possible to determine if one is not among Dr. Spiritus’ victims. According to Descartes, the answer is yes. Descartes states that God is an infinite, omnipotent, omniscient substance. He also says that humans are not capable of causing this thoug...

Contact Essay -- essays research papers

b) Why are astronomers using radio telescopes looking for far stars instead of a telescope? First of all, what is a radio telescope? The first non-visual spectral region that was used extensively for astronomical observations was the radio frequency band. Telescopes observing at these wavelengths are commonly called radio telescopes. Radio telescopes may be made much larger than optical/infrared telescopes because the wavelengths of radio waves are much longer than wavelengths of optical light. A rule of thumb is that the reflecting surface must not have irregularities larger than about 1/5 the wavelength of light that is being focused. By that criterion a radio telescope is several hundred thousand times easier to figure than an optical telescope of the same size In the movie "Contact," astronomer Ellie Arroway, played by actress Jodie Foster, searches for signs of extraterrestrial life using massive, Earth-bound radio telescopes. Much of Contact's scientific intrigue, based on Carl Sagan's 1985 bestseller, unfolds at two National Science Foundation-supported radio astronomy facilities where real-life astronomical mysteries continue to be probed. Scientists use the government-supported telescopes to detect radio waves not from distant civilizations but from planets, stars, galaxies and other objects in space. Radio observations extend astronomers' reach into space and time, letting them "see" through gas and dust in space to detect celestial objects whose visible light cannot be seen from Earth. In "Contact," Foster hears the first guttural, throbbing message transmitted by other-worldly life using the world's most powerful radio telescope, the Very Large Array in Socorro, New Mexico, a collection of 27 antennas spread in a three-armed configuration across the desert. NSF’s National Radio Astronomy Observatory runs the huge dishes, which Foster manipulates in the film from her laptop computer like a high-tech, movable Stonehenge, in reality. Electronically linked to simulate a single radio telescope up to 20 miles in diameter, the antennas can be bunched together or moved apart along railroad tracks into different configurations. About 700 astronomers visit the VLA each year to observe the universe. In "Contact," Foster gets her scientific start at another NSF-supported facility, the... ... fastest moving man made objects in the process. If those same probes were to be launched to the stars, however, they would take thousands of years to reach them! The distances to the stars are huge So huge, in fact, that the light from the nearest star to the Sun, a triple star system known as Alpha, Beta and Proxima Centauri, takes over four and a quarter years to get here. Since, according to special relativity, nothing in the universe can travel faster than the speed of light, it would seem that travel times with even the most advanced starships are going to be extremely long indeed. There are also highly exotic ideas, which lie on the tantalizing fringes of modern theoretical physics. If the universe is a multidimensional place with human beings only able to perceive three dimensions, perhaps a way can be found to shortcut through the 'higher' dimensions. These so-called wormholes are currently having their mathematics calculated by the theorists but if they can be utilized for travel then perhaps the entire universe will become accessible to us. Traveling to different planets may take no more time than traveling to different countries does now!

Nuclear Power :: Papers

Nuclear Power Entering the twenty-first century, six billion people inhabit the earth. A number that is expected to double in a hundred and twenty years, yet only 4% of that world population live in the United States. Even though the United States has only 4% of the population of the world, it still uses 25% of the world’s resources. Coal and oil are a major energy provider around the world, particularly in the US. Countries without these abundances have turned to nuclear energy, due to its supreme effectiveness. Nuclear energy produces more energy per unit weight than coal and oil, releases no pollutants into the atmosphere, and is less cancer causing than the burning of coal and oil. Yet nuclear power has been attacked in the US since the day that it was instituted as being a non-safe and environmentally non-friendly form of energy. Right now the United States does not have to worry about running out of fossil fuels for a long time, even though they generate 51.7% of the US’s power , and power almost all forms of modern transportation. But what happens down the road, when all of the natural resources are gone? In many countries, such as France, nuclear power is accepted and welcome. Why is this not the same way in the US? The media and all forms of entertainment have misconstrued the facts of nuclear energy. The word unsafe is synonymous with nuclear power in this country, but time has shown that there is so reason for this feeling. Americans do not hold the facts on this issue. They have the unwarranted fears of a mass and free speaking culture. Nuclear energy is safe, clean, and effective. The voice that is heard among the people is that nuclear energy is unsafe to the environment. There should be no debate about the environmental concerns of nuclear power. If there is anything that makes nuclear power unpractical it is government spending. Nuclear power is the cleanest form of power for a rapidly increasing world population. Nuclear reactors produce electri city by the fission of uranium, not the burning of fossil fuels. Nuclear power does not emit sulfur dioxide, nitrogen oxides, particulate soot, or greenhouse gases. In countries around the world nuclear energy is the largest source of emission-free electrical generation. Making one million kilowatt-hours of electricity in a natural gas power plant produces 550 tons of carbon dioxide. Producing the same amount in an oil-fired plant makes 850 tons of carbon dioxide and 1,110 in a coal plant.

Early Autum Essay

Langston Hughes short story â€Å"Early Autumn† demonstrates how distance and time can heal a broken heart. The main character Bill illustrates his distance from Mary showing that he has moved on with his life and relationship. The symbolism in Langston Hughes short story â€Å"Early Autumn† reveals the coldness and distance Bill has towards his and Mary’s once relationship. Hughes writes, â€Å"It was late afternoon. Nearly sunset. Cold. † (Hughes, n. d. , para 4) is a perfect example of Bill’s and Mary’s lost relationship. The sunset symbolizes the darkness and coldness in Bill and Mary’s now relationship. Bill is unable to see anything other than a casual friendship with Mary. The coldness has moved in and fall has packed her bags and winter has now arrived to take up residence. The trees are bare and lifeless, it resembles how Bill feels towards the relationship him and Mary once shared, he is emotionless almost lifeless towards Mary. For Bill the darkness is so thick he is unable to see anything in front of him. This woman standing before him may have been someone he once knew a long time ago but she is now someone he no longer recognizes. It’s like the grim reaper had made his appearance taking any life and happiness that had been for Bill and Mary’s once relationship. For Bill that part of his life had been buried and laid to rest a long time ago. The handshake symbolizes the finality of the once relationship for Bill. Mary still clings to the hope that Bill has feelings for her upon seeing him again (â€Å"Unconsciously, she lifted her face as though wanting a kiss, but he held out his hand. Hughes, n. d. , para 3). Bill extends his hand to Mary almost instantly severing any idea of romanticism that Mary could have possibly had. Bill extends his hand to Mary almost instantly severing any idea of romanticism that Mary could have possibly had. Bill’s almost business like handshake shows that he doesn’t foster the same ideas or cling to the same memories that Mary does. Bill treats Mary as a colleague, not someone he one shared such an intimate part of himself with. He buried his feelings for Mary the day she gave up on him and their relationship. He now only sees Mary as an acquaintance. The unknown people walking around symbolize how Bill and Mary really no longer know each other. Standing talking to Mary in the hustle and bustle of the New York City streets, (â€Å"A great many people went past them through the park. People they didn’t know† Hughes, n. d. , para 4). Throughout the years that past and the lives they have lived people have weaved in and out. They now both lived two separate lives; Bills life was full of happiness and Mary’s life full of regret. But standing there on the street that day they were strangers themselves. Many years passing just like the people passing by on the busy city street. Even though knowing each other, sharing stories and lives with each other once upon a time, having an intimacy knowing each other in and out. Distance, time and experience have made them different people almost foreign to each other in a way. They are no longer the people they once knew now they are strangers much like the people weaving in and out on the busy streets. The use of Bill’s wife’s name symbolizes his happiness with his marriage and his wife. Bill has made a life for himself and is a very happy man. He tells Mary of this life and of his family with such enthusiasm and pride that you can tell he is right where he wants to be. When talking with Mary at one point Bill mentions his wife by name, Mary on the other hand seems to forget her that she husband. Not once during her and Bill’s conversation does she mention him by name. (â€Å"Sure,† he replied. â€Å"You and your husband must have dinner with my family some night. Any night. Lucille and I’d love to have you. † Hughes, n. d. , para 7). Bill invites Mary and her husband to his house for dinner and calls his wife by name. Saying (â€Å"Lucille and I’d love to have you†. ) Bill added a hidden intimacy for his wife by calling her by name. Letting Mary know then and there he loved his wife, by stating her name brought a reality to the fantasy for Mary. Ending and crushing any hope Mary may had clung to. Bill was happy and enjoyed his life; never once regretting his decision’s. Whereas Mary will live with regret for the rest of her life. I truly enjoyed this short story; I think a majority of people can relate. For me it was the lost love or the one who got away. I think that everyone in some way has had this happen to them I know that I have. I can relate to Bill, I can understand how he loved someone so much and they could just move on so easily without so much as a single word. Having your trust broken and it taking years before you can trust someone again is a long and painful road. I think love and relationships are something a lot of people take for granted now a days. Fighting over petty things, putting material possessions over human worth seems to be the norm for most relationships now a days. Fighting with someone and instead of talking it over or working it out; people holding grudges or moving on without so much as a single word uttered. But for Bill it worked out he found love, true love. I think for me the story showed that sometimes it takes a couple of wrong ones until your find the right one. To not let one bad experience jade you for the rest of your life because at the end of it all there is always a silver lining.

Unit 332 Engage in Personal Development

Unit 332 – Engage in personal development in health, social care or children’s and young people’s settings. OUTCOME 1 1. 1 My responsibilities and duties include †¢ Helping pupils individually and in groups †¢ Support literacy †¢ Support numeracy †¢ Support science †¢ Supervising art activities †¢ Listening pupils read †¢ Support PE lessons †¢ Support the use of ICT in learning activities †¢ Supervising role play activities †¢ Supporting other members of staff †¢ Feedback teacher Going on school trips †¢ Providing resources for lessons †¢ Providing clerical support 1. 2 Since National Occupational Standards were introduced, the role of the TA becomes professional. It specifies the standard of performance we need to achieve in place of work together with knowledge and understanding that we need to meet standards consistently. What it means is that we need to develop all the time in order to keep in p eace with ever changing demands of the education.Also gaining Level 3 qualification gives us great opportunity to progress to the foundation degree. Teaching assistants should have qualities like: to be good communicators, use initiative, be a good listener, respect confidentiality, have emotional intelligence, be consistent, have sense of humour, will undertake CPD. OUTCOME 2 1. Practitioners should reflect on their practice in order to achieve good results in professional development. Being reflective: †¢ Demonstrates that practitioners are actively concerned about the aims. Enables practitioners to monitor, evaluate and revise their own practice continuously †¢ Requires an ability to look carefully at practice in order to develop new skills and understanding †¢ Requires an open-minded attitude †¢ Enhances professional learning and personal fulfilment through collaboration and dialogue between practitioners What does reflection involves? †¢ Reflection â₠¬ in† action, or thinking on your feet †¢ Reflection â€Å"on† action, or after the event †¢ Our thoughts and ideas †¢ Our colleagues ideas The views and knowledge gained from our own experiences and that of theoretical literature It might be hard to reflect on practice if we have negative feelings like anger or anxiety, lack of confidence, questions if my behaviour is consistent with model behaviour. Unrealistic, high expectations – I am a perfectionist, reluctance to accept help and admittance to weakness. 2. I reflected on my practice by completing PDP and answering 11 questions (see attachment 1 and 2). The aim was to spot where my strengths and weaknesses lie.In what ways I have succeeded in classroom and in what ways can I improve? To ensure â€Å"best† practice. To see what training might be necessary. This gives me the chance to build on my strengths and develop strategies to minimise my weaknesses. I also did my SWOK analysis (atta chment 3). 3. Everyone has different values, beliefs and preferences. We might get across people whose views we do not agree, our reaction to the differences and how they affect the way we work is a crucial part of personal and professional development.We need to respect and promote people’s individual views and wishes. Everyone’s values and beliefs are affected to different degrees by the same range of factors, they might include: family values, psychical, social and emotional stages of development, national/regional, cultural background, education, employment, religious beliefs and values. They might affect how we relate to people. It is important that we are aware of how we might behave differently towards people because it could make a difference to the quality of our work.Our beliefs and experiences can help us within our role. OUTCOME 3 4. 1 It is important to continuously engage in personal development to make sure that we are equipped with the necessary skills and knowledge not only to perform our current role but also to prepare ourselves for future opportunities and changes required in order to support success of our work place. There are ways in which we can plan personal development. through many types of learning experiences.We can attend training event or workshop, studying for a formal qualification, reading a newspaper, journal, even in discussion. In order to aid the continuous learning, we should keep personal development record. Is it important to identify priorities when agreeing to the plan because it contributes to stability and growth. It provides a basis for monitoring progress, and for assessing results and impact. It enables to look into future in orderly and systematic way, provides clear focus.