关于通信网络的英语论文参考文献

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1Wireless technology was little more than just a distant idea for the majority of ordinary consumers ten years ago. However, it has exploded over recent years with the use of 3G phones and wireless home computing increasingly commonplace.It would be foolish to suggest that wireless communication has reached its peak. Whilst mobile phones and home computing will continue to be the major focus in the quest for ever increasing sophistication within the technology, new applications are emerging daily.One company, Securecom Technologies, based in Ireland, have been at the forefront of harnessing wireless technologies in the area of personal safety. They already have a number of products in the marketplace designed to enable users to activate an alarm signal to a remote emergency centre wirelessly. Their Benefon range of applications are used by vulnerable elderly people, lone workers and VIPs to increase their sense of security and ability to effortlessly get in touch with help at the touch of the button.They are now in the process of developing PERUSE1, which stands for 'Personal Safety System Utilising Satellite combined with Emerging Technologies'. The Peruse project will develop a Wireless Personal Alarm (WPA) solution which will be carried by or worn on a person and will allow the user to summon help at the touch of a button. When the alarm has been activated, the WPA will transmit a low power signal to a satellite communications headset which will forward a message to an authorised number. This will include the identity of the person in distress, as well as their current location. However, the ingenuity of the technology goes further as it will also have the potential to transmit the user's current state of health and local environmental parameters.It is envisaged that the recipient of the users SOS signal will be a fully equipped Emergency Monitoring Centre to whom the user will have previously given full instructions as to the steps they would wish to have the Centre take on their behalf in the event of an emergency.There are two core components that are in the development phase. The wireless personal alarm (WPA) and a 'dongle' which provides the handset for satellite communication use which will have a low power wireless link to the WPA.The important issues here are that the two components will need to take into account size, cost, accuracy of location and battery autonomy. The main benefits will be that the device will be able to be worn or carried on a person discreetly. This makes it ideal for professions such as personal security, where the ability to communicate a message quickly and without fuss can often be of paramount importance. It will herald a new era in satellite communication. No longer will the user have to tap a keypad to enter a number nor will they have to move the handset for optimal signal strength prior to sending an emergence message. This technology will be invaluable to professions such as mountain rescue and will also be a tremendous benefit to those who enjoy hiking and climbing in the course of their leisure pursuits where conventional mobile phone technology can often be rendered useless.There are currently no known competitors for this potentially life saving technology for which Securecom has filed for both Irish and European Patent Applications. Prototypes have already been manufactured and pilot programmes and laboratory tests are well under way.UWB (Ultra Wide Band)2 is another example of emerging wireless technology. Alongside traditional wireless uses, UWB can also detect images through solid objects, such as people on the opposite side of a wall. This has led to an equal number of supporters and opponents.Although UWB can be used for consumer applications in a similar fashion to Bluetooth technology such as cable elimination between a PC and its peripheral equipment, the more interesting applications focus on its 'radar 'like imagery. These applications could be used to find people trapped in a burning building, locating hostages and captors behind a thick wall and finding objects such as those that might be buried in the ground. Heightened security at airports and other public buildings can use UWB technology to detect weapons on people and bombs in luggage and packages. In this age of heightened security, post 9/11, the benefits of this emerging technology should not be understated.A few companies have started to develop UWB products, including XtremeSpectrum, Time Domain and Aether Wire. XtremeSpectrum is developing products to enable the sending and receiving of multiple streams of digital audio and video for both battery powered and other consumer devices such as digital cameras, DVDs, DVRs, camcorders, MP3 players and set top boxes. Time Domain has developed a UWB chip set targeting three core technologies: wireless communication, precision location and tracking, and high definition portable radar whilst Aether Wire is working on miniature, distributed-position location and low data-rate communication devices. One of its goals is to develop coin sized devices that are capable of localisation to centimetre accuracy over kilometre distances.However, privacy violation is one of the major concerns of the technology's opponents. Any technology that can 'see' through solid objects can be used for illegal purposes as well as legitimate ones. In theory, a UWB-enabled system could 'look through' the walls of a house to locate valuable objects and could detect when the occupants are not at home. Supporters, however, could rightly point out that this is a dilemma shared by many technologies that are used to enhance public safety - the juggling act between increased security versus decreased personal freedom. It could be argued that baggage searches at airports via x-ray and metal detection are common examples of us giving up privacy for better security, a price most people are willing to pay.No other area is more at the forefront of the emergence of innovation in wireless technology than space exploration. Future missions to nearby planets like Mars will require space communication technologies that can provide an interplanetary satellite and navigation infrastructure via space systems that are far more compact and efficient than seen ever before. A longer term commitment will be necessary to resolve the challenges of efficient planetary communication due to the increase in distances involved as space exploration ventures further out into the solar system. To support planetary exploration, techniques developed for Earth-bound usage will be transferred to other planets as well. Exploration of Mars, for example, will require a high accuracy positioning capability such as a 'Martian GPS' as an aid to exploratory roving vehicles.This very day, the 'Mars Spirit' space rover continues to send data back to Earth, almost 18 months after it touched down on the red planet, surviving more than 4 times its expected mission length. One day it is highly likely that we may see astronauts walking on Mars carting around wi-fi enabled PCs. In a remote Arizona meteor crater, NASA has already begun testing a mobile wi-fi system that could enable those on a Mars mission to easily deploy wireless data connectivity at a transmission rate of just more than a megabit per second over a 2 square mile area, and then change that coverage area at will through the use of mobile access points, making it entirely feasible to explore different terrain on any given day.Tropos Networks3 developed the technology which NASA has adopted whereby the astronauts could have inter-connectivity via a three node mesh network. They would first establish a base communications station near their spacecraft and then set up an Ethernet connection between that base and a main access point. Then each node in the network would pick up its wireless connectivity from the access point.Testing is still in its infancy and there is some way to go before astronauts would be strutting their stuff on Mars and communicating wirelessly with one and other and with mission control in this way.However, the Mars Spirit space rover is still sending back images and data from the red planet today, relying heavily on wireless technology to do so. It may appear that these vehicles have been designed solely for the purpose of space exploration but closer scrutiny reveals applications that could also be modified and used on Earth. Unlike, say, a car manufacturing robot which knows where and when the engine or body appears on the assembly line, the Mars rovers are working in an unstructured and unknown environment. As a result, the rovers have had to learn about their new home through their own sensors, including a set of nine cameras on each rover. The rovers have two navigation cameras for a 3D view of their surroundings, two hazard avoidance cameras for a 3D view of nearby terrain and panoramic cameras to capture the images of the planet's surface. However, the rovers cannot just look around them, process the images and know where to go. Neither can the mission controllers on Earth grab a joystick and start steering the rovers whilst watching images being beamed back from thousands of miles away. A key reason is processing power. The central processor in each rover has a top speed of 20 MHz. Instead, during the Martian night, while a rover is 'asleep', a team on Earth with much more powerful computers programs its activities for the day ahead, and then sends basic instructions on where to go and how to get there. Along with taking pictures, each rover is examining the planet with several instruments on a robotic arm. The arms have 'shoulder', 'elbow' and 'wrist' joints for manoeuvrability and are equipped with four sensors: a microscopic camera for close up pictures of rocks, an alpha particle x ray spectrometer for determining the mineral content of rocks, another spectrometer for detecting iron and a rock abrasion tool for cutting through the layer of oxidation that forms on the surfaces of Martian rocks. As with the movement of the rovers, the arms are controlled mostly via prepared commands from mission control.Some observers have noted that some of these applications may prove useful here on Earth. For example, a robotic arm that doesn't require real time human control might be good for disabled people who use wheelchairs and can't control a joystick with their hands. Using its own sensors, it could reach out and get things for the person in the wheelchair, for example.In addition, a robot that can deal with new and unknown environments might save manufacturers money. In current factories with 'robotic' workers, when the company shifts to making a new product, the whole factory floor has to be reconfigured and the robots reprogrammed to deal with the new arrangement. A robot that could use feedback from sensors to figure out where things are could adapt to changes by itself, saving the company the time and effort of building a new structured environment and reprogramming the robots.With all the emerging technologies around and, inevitably, with more to come, the inevitable hurdle will be one of convergence and integration as the IT industry seeks to develop the tools that will be most sought after. Inevitably, there will be winners and losers.However, there is no doubt that the wireless phenomenon is reshaping enterprise connectivity worldwide and is definitely here to stay. Business needs information mobility for better customer interaction. Employees will be even more equipped to perform their job functions from their workplace of choice and, though this sounds like utopia, a societal change from office based to 'wherever they feel like being' based might conjure up an horrific vision of the future for company leaders who have enjoyed the traditions of having all their employees working from under the same roof.Another major issue has to be one of security. There are many issues when it comes to security over wireless networks. Wireless networks do not follow the rules of traditional wired networks. Many times, the signals are carried far beyond the physical parameters they are meant to be controlled within making it easier to intercept signals and capture information.There will also be the question posed of what happens to the have nots? - Those people and developing countries in particular that don't have the resources to wirelessly interact with others. The same thing could be said about the Internet itself but satellites could alleviate that problem far more quickly than the ability to put broadband connections in every office and home throughout the world.Another major hurdle has to be that business and society can only adapt at a certain pace. Technology evolves far more quickly and there may be many a product developed for which the demand is not yet there. But the mobile phone and PC market driven by what the consumer wants will determine what the future of wireless holds.But there is no question that wireless communication is here to stay and will grow even more.Signs of the new wireless technologies abound. Consumers are setting up wireless local area networks (WLANS) in their homes. These allow multiple computers to hook up to one fast internet connection or laptop users to connect from the comfort of their sofa or back garden patio. Away from home, 'Hotspots' that permit wireless connection to the internet are popping up everywhere, in book stores, coffee shops, airports and even pubs. Within the next year, airlines are expected to announce the availability of wi-fi during flights. However, until there is increased competition in the market place, this new epoch will be there for the privileged few as opposed to the mass market who will still be relying solely on their mobile phones for wireless connectivity on the move. It remains to be seen whether the new generation of 3G phones has arrived too late to push aside wi-fi and it's even conceivable that mobile phone companies could one day find themselves obsolete unless they look for new ways to attract and retain customers.But issues like security, along with the problems of cost, intrusion on privacy and identifying such things as hotspot locations is not going to hold wireless communication and technology back. In the end, there will always be solutions to problems and wi-fi is no different in this respect.David Reed, an adjunct professor at MIT's Media Lab in Cambridge, Massachusetts has been studying the future of wireless communications. He draws a comparison with the new wi-fi revolution with that of the 'paperless society' which was often mooted in offices and homes all over the world with the advent of the PC. He said, The market will push us towards a wireless future. People love paper but I can't find a single person who can say that about wires.4As more wi-fi systems are developed which will, in turn, drive the cost down it will become an increasingly less disruptive way to communicate in the future and it will become very difficult for anything else out there to compete with that.2It is used by millions of people every minute. For many people the Internet is a "room" that is situated somewhere behind their computer screens in a cyberspace. Though the Internet exists for about a decade it has become the medium of the new network society. The popular and commercial spreading of the Internet has been exceedingly significant - promoting changes in almost every sphere of human activity and society. From the very beginning of the Internet in 1991, it has completely changed the way firms do business, as well as the way customers buy and use products and services. The Internet gives extra opportunities for marketing. The spreading of the Internet has been so impetuous that it has been the point for well-grounded analysis. The Internet, virtual reality, can or cannot have negative effects on our culture and society? This paper is concentrated on the Internet phenomenon and on the spreading of the Internet culture and its effects on people. The first ideas appeared in the 1950s. In the 1980s, technologies that became the basis of the modern Internet began to spread worldwide. In the 1990s the World Wide Web was used all over the world. The infrastructure of the Internet spread all over the world and the modern world wide network of computers have appeared. It spread amidst the western countries, then came into the developing countries and created a worldwide admittance to communications and data and a digital divide in admittance to this new infrastructure. While studying the amount of Internet users, the Internet had 30 million users on 10 million computers linked to over 240,000 networks in about 100 states. The last figures indicate the fact that International Data Corp values that 40 million people are home web users in the USA in 1999, which consists of 15% of the population. “Le Monde” in 1998 published that 100 million people use the Internet all over the world. Jupiter Communications estimates that active Internet users - 4 to 5 million USA customers - shop regularly on the Internet by 2000, which represents 3% of grown-ups.The Internet is a very attractive marketing tool with the possibility to customize pages, as well as new promotional systems, giving firms the possibility of communication and promotion effectively by adapting to consumers’ likings. Interactive traits of the Internet permit asking customers their likings, and then the firm can adapt product offers and promotions to these likings. It provides the effective recruit of new customers. For instance, some car manufacturers ask Internet users for concrete information and in return give potential customers a $1,000 discount coupon or a free CD player coupon. 这里有很多，不知是通讯的具体什么方面，看看这里，找你想要的吧