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
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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
6.4 The Sydney Olympic Games system IBM was responsible for the computer systems which were used in the 2000 Olympic Games. There were a number of components to the system, these included: A website which was publicly accessible and which contained features on the Games, the competitors and the results. A Games management system which administered the logistics of the Games, for example arranging transportation, accreditation and accommodation for athletes.
6.3 The architecture The architecture of the system is shown in Figure 4. It consists of a number of components. The most important of these is the web server. This communicates with browsers used by customers. There are two other computers that are used in the system which are directly connected to the web server: a mail server which sends and receives mail from customers and a mailing list server which administers the mailing lists of customers and their interests. Both these servers communicate with the
6.1 The architecture of a typical e-commerce system Before finishing this unit it is worth looking at the architecture of a typical e-commerce system in order to see some of the technologies. This is followed by details of a real application which I shall use to discuss some of the issues involved in distributed system development. The description used is closely modelled on the Amazon site.
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
5.5 Problems with transactions A distributed transaction is a sequence of operations applied to a number of distributed databases which form a single functional step. For example, a transaction which moves an amount of money from a customer's account to an account owned by the same customer is an example of a transaction. It consists of two operations: the operation of debiting one account and the operation of crediting another account. There are a number of problems associated with distributed transactions. This section w
5.1 Security and privacy The internet is not a particularly secure place. There are two aspects to this: the first is that information is widely published throughout the internet which can be used for criminal and near-criminal activities. The second aspect is that since the internet is an open system, details of its underlying technologies are freely available to anybody. This means that the way data passes through the internet is in the public domain; the consequence of this is that, theoretically, anyone with the
3.4 Newsgroups A newsgroup is a collection of internet users who are interested in a particular topic. The topic may be a technical one, for example the LINUX operating system, or a recreational one such as fly fishing. Members of a newsgroup send messages associated with a particular issue such as the date of release of the next version of LINUX or the efficacy of using certain fiies on certain rivers. Each message – known as a posting – will contain the user's thoughts on the topic. Once
1.6.3 Supporting users and user processes Use of a database involves user processes (either application programs or database tools) which must be developed outside of the database development. In terms of the three-schema architecture we now need to address the development of the external schema. This will define the data accessible to each user process or group of user processes. In reality, most DBMSs, and SQL itself, do not have many facilities to support the explicit definition of the external schema. However, by using built-in q
1.3 Summary This section briefly discussed the public awareness of computers and how quickly this has developed from a situation where computers hardly impacted on most people to one where they are involved in virtually every facet of modern life. As an illustration, you examined the contents of your wallet to determine how much data about you (your persona) might be kept by a variety of organisations. This sets the scene for developing an understanding of how this affects you as an individual in modern
Introduction This course examines four of the ‘grand theories’ of child development: behaviourism, social learning, constructivism and social constructivism. This OpenLearn course provides a sample of Level 2 study in Education.
Working with young people in sport and exercise
This unit examines the special considerations of coaching or instructing young people in sport and exercise. The physiological differences between children and adults will be considered along with the practical implications of coaching young people. First published on Wed, 23 May 2012 as Author(s):
Geometry
Geometry is concerned with the various aspects of size, shape and space. In this unit, you will explore the concepts of angles, shapes, symmetry, area and volume through interactive activities. First published on Tue, 04 Dec 2012 as Geometry. To find out more visit The Open Un
7 Logarithms The equation 23Â =Â 8 means that 3 is the index of the power to which we raise the number 2 to produce 8. A logarithm is an index, and in this example, 3 is the logarithm of 8 to the base 2. We write this as Log2 8Â =Â 3 These two equations are identical: 23Â =Â 8 and log2 8Â =Â 3 They express the same fact in the language of logarithms. 4.1.1 Getting off to a good start You may find it useful to plan the way you will start your exam. Having a routine can be calming when under pressure. This is from a student who recommends a checklist:
I have a mental checklist of what I need to do once I've turned over the paper. I do this because I used to rush in and answer the fir
