Lesson Title: Digging Deeper: Mission San Saba
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40
pages
English
Documents
Obtenez un accès à la bibliothèque pour le consulter en ligne En savoir plus
- cours - matière potentielle : duration
- leçon - matière potentielle : student handout
- cours - matière potentielle : title
- persia chart with a partner
- victory
- spanish motives
- student product
- presidio
- san sabá
- mission
- view
- students
chapter 2
INFORMATION SYSTEMS A ND DATABASES
Outcomes • applies an understanding of the nature and function of information technologies to a specific practical situation (H1.1) • explains and justifies the way in which information systems relate to information processes in a specific context (H1.2) • analyses and describes a system in terms of the information processes involved (H2.1) • develops solutions for an identified need which address all of the information pro-cesses (H2.2) • evaluates the effect of information systems on the individual, society and the environ-ment (H3.1) • demonstrates ethical practice in the use of information systems, technologies and processes (H3.2) • proposes ways in which information systems will meet emerging needs (H4.1) assesses the ethical implications of selecting • and using specific resources and tools (H5.2)
Overview The emphasis in this chapter is on the infor-mation processes of organising, storing and retrieving with database systems and hyper-media. You will gain a greater understanding of information systems and develop skills with relational databases.
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Core
2.1 Information systems
INPUT
ST ORAGE
PROCESSING CONTROL
OUTPUT
OUTPUT
f an information ocesses requiring hey perform the storing/retrieving, The relationship n Figure 2.1. The ation s stems are
Figure 2.1 Information system. Characteristics of information systems Information systems are created to provide access to information for an organisa-tion or individual. For a large number of information systems, the data is held in a database and access is achieved using a DBMS. The characteristics of an informa-tion system are the: • Organisation of data into information. Data must be organised before it can be stored and analysed by the information system. Careful thought is needed to organise data; otherwise, the resulting information will be meaningless. Organising may require sorting, summarising or classifying. Data in an information system is organised into data structures using such organisational methods as data dictionaries. • Analysis of information to give knowledge. Access to information and the resulting knowledge is the purpose of an information system. For people to gain knowledge from information, the information must be analysed. Information systems provide a range of tools for the analysis of data, such as tables, queries and reports. People make decisions based on the information they receive from an information system.
IT IT Fa Fa ct ct A spider or crawler is a program that visits Web sites and reads their pages to create entries for a search engine. It is called a spider because its ‘legs’ span a large area of the ‘Web’.
Types and purposes of information systems The types of information systems and their purposes are changing with develop-ments in information technology. These types and purposes are also not mutually exclusive. They often overlap and change as new applications or new versions of existing applications are introduced. Five types of information systems are examined in this section. Transaction processing systems (TPSs) collect, store, modify and retrieve the daily transactions of an organisation. Some examples of the application of TPSs are buying goods at a point-of-sale (POS) terminal, processing credit card pay-ments and tracking receipts of materials from suppliers. Organisations rely heavily on their TPS. A breakdown will disrupt operations or even stop the business. For this reason, well-design backup and recovery procedures are essential. There are two types of transaction processing: batch processing and real-time processing. Batch processing collects the transaction data into a group and processes it later. It is currently used where transaction data is on paper, such as processing cheques. Batch processing has a time delay, and this may be a significant disadvantage. In real-time processing, each transaction is immediately processed. It provides instant confirmation of a transaction but does require access to an online database. Decision support systems (DSSs) assist people to make decisions by providing information, models and analysis tools. A DSS can be used on a daily basis or when an organisation has to react to something unexpected or make changes. One example of a DSS is a system that analyses the stockmarket and helps the user make decisions about buying and selling shares. A DSS creates a mathematical model of the variables affecting the decision, using statistical tools, databases, spreadsheets and graphics. The model allows a manager to ask what-if questions by changing one or more of the variables and seeing the projected results. What would happen if the price were raised? What would happen if the organisation changed the design of its package? The DSS depends on the accuracy of the mathematical model and the ability of the manager to formulate appropriate questions. Expert systems are a type of DSS. Expert systems provide information and solve problems that would otherwise require a person experienced in that field (an expert). They are useful in diagnosing, monitoring, selecting, designing, predicting and training. An expert system asks users a set of questions and compares their answers to a knowledge base. The knowledge base is a set of general facts and if-then rules supplied by an expert. The expert system must reason to obtain a possible solution. For example, one expert system has been designed to help doctors diagnose infectious blood diseases and prescribe antibiotics (see Figure 2.2). The system uses the patient ’ s medical history, symptoms and laboratory test results as its input and compares these to its knowledge base. If a match occurs, the system uses its pharmacological knowledge base to recommend an antibiotic. The solutions from an expert system are not always correct, and it is up to the user to accept or reject the solution.
Information systems and databas
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Core
Figure 2.2 Expert systems are used in medicine. Management information systems (MISs) provide information for the organisation ’ s managers. An MIS presents basic facts about the performance of the organisation. Some common examples of MIS output are reports on sales, stock inventory, payroll, orders and budgets. The fact that people are aware of how the performance is measured helps managers motivate workers and make decisions. A special type of management information system is called the Executive Information System (EIS). The EIS is designed for the information needs of senior managers and provides information on strategic issues, using data from the share market, commodity prices, interest rates and other economic indicators. Office automation systems provide people with effective ways to complete administrative tasks in an organisation. An office automation system uses a range of software tools, such as word processors, spreadsheets, databases, desktop publishing, presentation programs and project management software. Office automation systems also use communications technology, such as Web browsers, email, facsimile, and video-conferencing. In office automation systems, letters and documents are constructed quickly, edited if required and easily stored for future reference or re-use. Email improves productivity by delivering messages and data more quickly than the paper-based interoffice mail system could. Desktop publishing software is used to create high-quality flyers, reports and brochures. Examples of database information systems Most information systems store data in a database. Information systems that use a database are called database information systems . You will remember from the Preliminary course that a database is an organised collection of data. Databases are accessed by a database management system (DBMS). A DBMS has no data in it. It is a software package that allows the user to enter, maintain and provide access
