6.1 Further reading There is not a lot published on distributed development paradigms. The book by Coulouris et al. [2] indirectly introduces some of the paradigms introduced in this unit. Lynch's book [3] on distributed algorithms is full of algorithms which are message passing based. The book by Patzer and 14 others [4] is a good practical introduction to many of the technologies detailed in this unit. One of the few current books on JavaSpaces has been written by Freeman et al. [1].
4.1 Introduction Many of you will already be familiar with event processing if you have developed visual interfaces with the later versions of Java. Developing such an interface consists of a number of steps: A visual object such as a button is placed in a container such as an applet or a
object.
2.2 Fixed and adaptive protocols The protocol described above for a simple naming service is an example of a fixed protocol. This is a protocol whose vocabulary is fixed: it is embedded in the client and server's code and data and does not change. An adaptive protocol is one where the protocol changes. A fixed protocol could change over a period of time because the functionality provided by a server changes. However, this change will be over months or years rather than over seconds. There are some instances wher
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
2.7 Other commercial websites So far I have detailed e-commerce applications which are connected with very large organisations; to conclude this section it is worth looking at a number of smaller applications, many of which are distinguished by the fact that they are novel. They are in contrast to the applications discussed in previous subsections which mainly consist of standard functions such as order processing. 1.7 Testing The aim of testing is to uncover errors in the design and implementation of the database, its structure, constraints and associated user and management support. Testing is usually considered to involve two main tasks – validation and verification. Without adequate testing users will have little confidence in their data processing. Validation answers the question: has the right database been developed to meet the requirements? It attempts to confirm that the right database has been co 1.6.2 Populating the database After a database has been created, there are two ways of populating the tables – either from existing data, or through the use of the user applications developed for the database. For some tables, there may be existing data from another database or data files. For example, in establishing a database for a hospital you would expect that there are already some records of all the staff that have to be included in the database. Data might also be bought in from an outside agency (address 5.2 Art and the common computer Art is difficult to define. But all art involves the Exercise of human skill. A natural object, such as a piece of driftwood, a flower, a bird song, can move us to admire it as beautiful or intriguing or comforting, but it isn't art. Artists (be they photographers, painters, sculptors, actors, musicians, authors or dancers) use their skill to transform natural objects, materials or signs (paint, clay, their own body or voice, the sounds of musical instrument, words) into somethi 5.1.2 The human genome All life is ‘encoded’ chemically in genes. What this means is that the structure of an organism, the organs it possesses, its colouring, and so on are all determined by different genes. A very simple organism may have just a few genes, and a complex one tens of thousands. The ‘map’ of an organism's genes is referred to as its genome. It shows, in essence, which genes give rise to which characteristics or traits of the organism. The word ‘template’ would describe the 4.1 Where am I and how do I get to … ? Computers can be used to find things and the obvious thing they can find is information. The World Wide Web (WWW or just the web) is just one example of a vast store of information which can be searched to find what you want using computers (The web consists of linked data which is accessed via the internet using a browser). But computers can also ‘find’ things in the sense of locating them geographically, either by generating maps that can be used for navigation or by locat 3.4.1 A computer system is the combination of: the computer (with its processor and storage); other equipment such as a scanner or printer, the software programs that make it all work (software programs that are designed to help with some human task are often referred to as applications). 2.3 Summary This section showed that computers pervade our daily lives, but that many of them are invisible to us. It investigated the information requirements of certain individuals, such as shoppers and doctors. You learned that their requirements can range from the simple and obvious to the complex and not so obvious. You also learned that it is not just individuals who require information: it is also essential to the operation of organisations. The example of loyalty cards was used 1.1 What this unit is about Each venture Is a new beginning, a raid on the inarticulate … T. S. Eliot, ‘East Coker’ Some years ago I was playing with my nephew. ‘Guess what’, he said. ‘My gran remembers before there was television!’ He was clearly thinking about the past in terms of ‘before there was television’. At that time, I was working in computing, and most people couldn't really un Learning outcomes After studying this unit you should be able to: identify some of the instances in daily life where a computer is, or is likely to be, involved; given a simple scenario, list most of the obvious information or data required by the parties in that scenario, and give some examples of how the information or data might be used; explain briefly what perceptual data is, and how it is turned into a form that can be used by a person for reasoning or by a co Introduction This unit is from our archive and it is an adapted extract from Data, computing and information (M150) which is no longer in presentation. If you wish to study formally at The Open University, you may wish to explore the courses we offer in this curriculum area. Computers are used to find, store, process and share data and information. The World Wide Web is an example 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. Introduction There are many approaches to using film music in the classroom, including: a focus on pupil experience; a focus on the structure of composition; a focus on the relationship between music and image; This course will explore some of these approaches through various activities. Find out more about studying with The Open University by Author(s): Prices Introduction This course introduces you to the concepts of: It will provide you with the skills and confidence to engage in further OER work as both creator and user. Find out more about studying with The Open University by Am I ready to study in English?
This unit looks at a wide variety of ways of comparing prices and the construction of a price index. You will also look at the Retail Price Index (RPI) and the Consumer Price Index (CPI), indices used by the UK Government to calculate the percentage by which prices in general have risen over any given period. You wil also look at the important statistical and mathematical ideas that contribute to the construction of a price index.Author(s):
Even if you feel confident using English in everyday situations, studying in English at higher education level might present extra challenges. This free course, Am I ready to study in English?, provides an opportunity for you to reflect on your English language skills through a series of academic exercises.
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