4.9 Bluetooth The driving force for the development of the Bluetooth standard was to eliminate the need for connecting wires between local IT devices such as keyboards, monitors, printers, PDAs (Personal Digital Assistants), cell phones and headsets. This was already possible using infrared technology, but the requirement for line-of-sight positioning between the communicating interfaces limits infrared's usefulness. Because Bluetooth uses radio waves, Bluetooth devices can communicate with each other with
4.7 WiFi data rates and operating range Just as for Ethernet, developments in technology have increased the achievable data rates since the first WiFi standard was developed in 1997. At the time of writing, the latest WiFi standard to be published – IEEE 802.11g – defines a data rate of 54 Mbps. 3.3 Wired network configurations Network nodes can be connected together in different arrangements known as topologies. We are going to describe four common topologies that you may come across. 1.2 Skimming to get an overview A well-structured document usually contains a number of clues about its contents. Skimming is the practice of finding and using these clues. These are: visual clues such as a document's title, headings, subheadings, figures and figure captions; words in boldface and italics; and numbered and bulleted lists; verbal clues such as the introduction and conclusion or summary, and the first (or sometimes the last) sentence in each paragraph Learning outcomes After studying this course, you should be able to: understand and use correctly terms introduced in this course in relation to communication networks understand general principles involved in data exchange between IT devices work with numbers expressed in scientific notation, and use the Windows calculator to perform calculations on these numbers. 1 The incredible shrinking chip Two Scottish computer engineers with little or no physics knowledge set out to make a semiconductor transistor. This was 50 years ago, and their efforts gained them the Nobel Prize. The versatility of that transistor is now at the heart of the electronics industry. Millions of transistor switches are shrunk down into the microprocessors that are found in computers, mobile phones and almost everything else electrical. The first transistor took years to plan and make; today more are made 7.3 Using flowcharts to describe a task Application programs are designed to perform specific tasks. These tasks range from the relatively simple to the extremely complex. In this section you will look at what is involved in planning a program to perform some simple tasks. In order to write a program, the task the program will perform has to be first written as a list of actions. The actions have to be given in an order that will ensure the task is carried out successfully. 7.3 Quality of customer service This is probably the key determinant of customer satisfaction. Most online transactions go through flawlessly. But some don't. Goods fail to arrive, or are delayed, or delivered to the wrong address. Or what is delivered doesn't match what you ordered. With a real-world bricks-and-mortar retailer, the solution is obvious: you phone or turn up at their premises and speak to a human being. But what do you do if an online order goes wrong? Whom do you phone? And where is the number for customer 4.4.1 Voltage, current and resistance
Voltage (or, more correctly, electromotive force, emf – but I shall follow common practice and just say voltage) is a measure of the force with which electricity is 'pushed'. Nothing happens, however, unless there is an electric circuit, which is a path from one terminal of a voltage source (the battery, in this case) to the other, along which the electricity can flow (Author(s): Acknowledgements Except for third party materials and otherwise stated (see terms and conditions), this content is made available under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence 4.3 Ethical and legal considerations You will need to be aware of privacy and confidentiality in relation to online communication. Email is generally considered private and should not be quoted without permission. Some conferences are not wholly public, so messages should not be copied outside the conference. Online discussion may be read by people from other cultures and backgrounds, so be careful to avoid giving offence. Although people are usually very tolerant, it is still possible that someone could sue for libel. 4.2.4 Make clear your perspective Try to avoid speaking impersonally: 'This is the way it is…', 'It is a fact that…'. That will sound dogmatic and leaves no room for anyone else's perspective. Why not start, 'I think…'? A common abbreviation is IMHO (in my humble opinion) – or even IMNSHO (in my not so humble opinion). If you are presenting someone else's views, say so, perhaps by a quote and acknowledgement. 2.2 Evaluating web resources One of the good things about the Web is also one of its drawbacks – anybody can publish anything. This means that the Web is an amasing source of information and is full of fascinating resources. However, in order to get to useful information you may have to work your way through lots of irrelevant material. Even when you think you have found something relevant, how do you know it is reliable, and how can you judge the quality, accuracy and bias of what you find? Most publicatio References 6.6 Modelling the relationships between use cases There are two situations when you would consider adding details to a use case diagram: to identify a common task (and its associated scenarios) that is shared between two or more use cases; to record any alternatives or additions to the main success scenario as separate use cases. In both situations, the new tasks are shown as new use cases (ovals) and, as you will see below, the UML provides a suitable notation (known as 6.4 Scenarios The purpose of a use case is to meet the goal of its associated actor(s), such as a guest making a reservation with a hotel. This implies that a use case should include everything that must be done to meet that goal. For example, if it is necessary to check the availability of rooms in the hotel for the desired length of stay before accepting a reservation, then we expect the use case to contain that check. In general, a use case contains a narrative about the flow of events that specifies a 7.2.1 E-shop This is the most ubiquitous form of commerce on the World Wide Web. It involves a company presenting a catalogue of its wares to internet users and providing facilities whereby such customers can purchase these products. Almost invariably such a site will contain facilities for ordering and paying for products by means of credit cards. The sophistication of sites described by this business model range from just the simple presentation of a static catalogue to the presentation of an interactiv 5.6 Design Designing a distributed system can also be a problem, for example the fact that computers in a distributed system are joined by communication media which can stretch over thousands of miles provides an added dimension to the design process in that response time can be a problem. Another, equally serious problem is that of reliability, for example the fact that a hardware malfunction can bring down a poorly-designed distributed system. As an example of one design problem that a distribut Harrowlegal-Contract Dispute Lawyers
Activity 17: exploratory
Video link (see supported sites below). Please use the original link, not the shortcut, e.g. www.youtube.com/watch?v=abcde
Author(s):