INFS 328 Systems Analysis and Design

Size: px

Start display at page:

Download "INFS 328 Systems Analysis and Design"

Carol Newman
6 years ago
Views:

1 INFS 328 Systems Analysis and Design Session 6 System Design Part 1 Lecturer: Prof. Ellis Edwin Badu, Dept. of Information Studies Contact Information: eebadu@ug.edu.gh College of Education School of Continuing and Distance Education 2017

2 Session Overview In the Analysis phase, you studied how to analyse a current information system by coming up with a logical model of the new system and other development strategies. With this phase you will learn about physical design of an information system that will meet the specifications described in the system requirements document. System design tasks include output and user interface design and data design. Slide 2

3 Session Outline The key topics to be covered in the session are as follows: Output Design User Interface Design Input Design Data Design Slide 3

4 Topic One OUTPUT DESIGN Slide 4

5 System Design Output Design Output Design As a system analyst, you will have to design the screen for your users and other output printed forms. The following are the essential elements of the output design. 1. Purpose of the output. 2. Audience of the information and why the information is needed and how the information will be used. 3. Specific information needed. 4. Form of output either printed, screen view or both or the type of device the output will go to. 5. When the information will be provided and update frequency 6. Security and confidentiality.. Slide 5

6 System Design Output Design Types of output The type of output needed and the technology needed usually are decided during the analysis phase based on user requirements. In the design phase, actual reports, screen forms and other delivery methods are designed. Some of the other delivery methods are: Internet, E- mail, Audio output, automated facsimile systems, computer output microfilm, computer output to laser disk.. Slide 6

7 System Design Output Design Types of output Internet-based information delivery. Some organisations use the internet to reach new customers and markets so web designers must provide user-friendly screen interfaces that display output and accept input from customers. For example, a system provides customised responses to product inquiry or requests technical support, the system responds with appropriate information from an on-site knowledge base. This is an essential means of internal and external business communication. has virtually replaced traditional memos and printed correspondence. Companies send new product information to customers via and financial services companies use messages to confirm on-line stock trades. Slide 7

8 System Design Output Design Types of output Audio Output This can be attached to an message or inserted as an audio clip in a Microsoft word document. In addition, many organisations use automated systems to handle voice transactions and provide information to customers. For, example, by using a telephone keypad, a customer can confirm an airline seat assignment, check a credit card balance or determine the current price of a commodity. Automated Facsimile System Some companies use automated facsimile, sometimes called faxback systems to allow a customer to request a fax using via the company s website or by telephone. The response is transmitted in a matter of seconds back to the user s fax machine. Slide 8

9 System Design Output Design Types of output Computer Output Microfilm (COM) Examples of these are Microfilm and Microfiche. These capture an image of a document and produce film output. Users then retrieve, view and print the images. Microfilm records the images on a roll of film, and microfiche records images using a small sheet of film. Computer output to laser disk (COLD) This is another way to store images of paper documents. Using COLD technology a paper document is scanned and the digital image is stored on a high density laser disk medium. COLD technology also enables rapid information retrieval of formatted information. Slide 9

10 System Design Output Design Other Specialised Forms of Output There are other specialised forms of output. Some of them are briefly described below: retail point of sale terminals to handle computer based credit card transactions, print receipts and update inventory records automatic teller machines special purpose printers that produce labels, photos driving licenses and even lottery tickets plotters that produce high quality images such as blue prints maps digitised photos that companies can print on employee identification cards Slide 10

11 System Design Output Design Printed and Screen Output Reports can be printed outputs or screen outputs. Whether printed or viewed on screen, reports should be attractive and easy to understand. Managers and users judge an entire project by the quality of the reports. Reports can be classified into: Detail reports, Exception reports and Summary reports. The users of an information system must approve all report designs in advance as the information is delivered to them. In designing a report, a sample report called Mock-up or prototype is normally prepared for review by users. Reports can be created using word processor, report generator or a printer spacing chart. The principles for report design include report headers and footers, page headers and footers, column headings and alignment, column spacing, field order and grouping of detail lines. Slide 11

12 Questions Individual Assignment: List eight delivery outputs. Forum Question Explain the difference between printed and screen output Slide 12

13 Topic Two USER INTERFACE DESIGN Slide 13

14 User Interface Design Guidelines for User Interface Design A good user interface design is based on ergonomics, aesthetics and interface technology. Ergonomics describes how people work, learn and interact with computers. Aesthetics focuses on how an interface can be made attractive and easy to use. Interface technology provides the operational structure required to carry out the design objectives. Every interface should therefore be designed to make it easy to use, be attractive and efficient and must be guided by the following points. Slide 14

15 User Interface Design User Interface Design Guides Focus on basic objectives. Facilitate the system design objectives rather than calling attention to the interface Build an interface that is easy to learn and use. Promote features that promote efficiency by organising tasks commands and functions in groups that resemble actual business operation. Make it easy for users to obtain HELP or correct errors. Ensure that HELP is always available. HELP screens should provide information about menu choices, procedures, shortcuts and errors. Slide 15

16 User Interface Design User Interface Design Guides Minimise input problems by providing messages, for example, an ID number not found. Create an attractive layout and design by using appropriate columns to highlight different areas of the screen, avoid gaudy and bright columns. Use familiar terms and images. For example, file, exit, help. Use familiar commands such as cut, copy and print etc. Slide 16

17 Questions Individual Assignment: Design a printed output for a student registration system. The output should include statement name, name of residence, course, department and name of faculty. Let the heading be student registration system. Forum Question What do you understand by user interface? Slide 17

18 Topic Three INPUT DESIGN Slide 18

19 Input Design Input Design After designing the output, the input should also be designed as a second part of the interface. Input technology has changed dramatically. Businesses use the new technology to speed up the input process, reduce costs and captured data in new forms such as digital signature. A good input design ensures quality, accuracy and timeliness. Input design is about how data will be captured and entered into the information system. Slide 19

20 Input Design Input Design Data capture uses an automated or manually operated device to identify source data and convert it into computer readable form. Examples of data capture devices include credit card scanners and bar code readers. Data entry is the process of manually entering data into the information system, usually in the form of key strokes or mouse clicks. Every input design must have the following objectives. Slide 20

21 Input Design Six Main Objectives of Input Design Select a suitable input and data entry method. An example is batch input (entry on a specified time schedule) or online input such as source data automation. Reduce input volume. (Reduce the number of data items required for each transaction in order to reduce volume). This avoids unnecessary labour cost as data capture or data entry require time and effort. Design attractive data entry screen. Slide 21

22 Input Design Six Main Objectives of Input Design Use validation checks to reduce input errors. Reducing errors improves data quality. Design required source documents. A source document is a form used to request and collect input data, trigger or authorise an input action, and provide a record of the original transaction. During the input design stage, you develop source documents that are easy to complete and inexpensive. Develop effective input controls. Input control includes the necessary measures to ensure that input data is correct, complete and secure. There are some common types of input devices you should be familiar with. Slide 22

23 Input Design Common Types of Input Devices The following are some input devices: Biological feedback device this creates digital image of biological data such as finger prints, retina patterns etc. Digital collection device this is a fixed or portable device that can read data on site, like ATM. Digital camera. Electronic whiteboard this is an electronic version of traditional white board that can capture and store text or graphics written or drawn on the board. Slide 23

24 Input Design Common Types of Input Devices The following are some input devices: Graphic input devices include light pens, digitisers and graphics tablets that allow drawings to be translated into digital form. Hand held computer stylus device that allows users to form characters on the screen of a hand held computer. Input devices for physically challenged Internet workstation enables user to provide input to web-based intranet or internet recipients Key board - Slide 24

25 Input Design Common Types of Input Devices The following are some input devices: MICR (magnetic ink-character recognition) technology used to read magnetic ink Mouse pointing device that allows the user to move the insertion point to a specific location on a computer screen Micro phone a microphone converts sound waves into digital information Scanner device that reads printed bar codes, characters or images Terminal device such as screen on monitor Slide 25

26 Input Design Common Types of Input Devices Video input video camera input, in digital form that can be stored and played later Touch screen sensors that allow users to interface with the computer and select options by touching specific locations on the screen Voice input device device that allows users to enter data and issue commands using spoken words Wireless input wireless input devices are wireless versions of traditional scanners, barcode readers and data collection devices Radio Frequency Identification (RFID) this is a technology used to track down items in a wide range of information systems including inventory control, point- of-sale and monitor peoples movement in security management system Slide 26

27 Questions Individual Assignment: List ten common types of inputs. Forum Question Discuss five input devices and their uses Slide 27

28 Topic Four DATA DESIGN Slide 28

29 Data Design Introduction Data Design touches on the physical design plan for data organisation, storage and retrieval. It is exactly the same as data base management course you studied in the first semester of level 300. Because of this, the section will provide only a summary of what you have already studied in level 300. Summary of Data Design Before constructing an information system, you must understand basic data design concepts, including data structures and the characteristics of file processing and database systems including Web-based database design. The following is a summary of the essential facts you should know. Slide 29

30 Data Design Files and tables These usually contain data about people, places, things or events that affect the information system. File processing systems also file-oriented systems, manage data stored in separate files including master files, table files, transaction files, work files, security files and history files. A database consists of linked tables that form an overall data structure. A data base management system is a collection of tools, features, and interfaces that enable users to add, update, manage, access and analyse data in a database. Slide 30

31 Data Design Database Management Systems (DBMS) These are more powerful and flexible than traditional file oriented systems. A database environment offers scalability support for organisation-wide access, economy of scale, data sharing among user groups, balancing of conflicting user requirements, enforcement of standards, controlled redundancy, effective security, flexibility, better programmer productivity and data dependence. Database management system components include interfaces for users, database administrators and related systems, a data manipulation language; a scheme, and a physical data repository. Other data management techniques include data warehousing, which stores data in an easily accessible form for users access and data mining which looks for meaningful patterns and relationships among data. Slide 31

32 Data Design Task Data Design Data design tasks include creating an initial entity relationship diagram; assigning data elements to an entity, normalising all table designs; and completing the data dictionary entries for files, records and data elements. Files and database tables should be sized to estimate the amount of storage space they will require. File and database control measures include limiting access to the data, data encryption, backup/recovery procedures, audittrack files and internal audit fields. Slide 32

33 Questions Individual Assignment: 1. What factors would you consider when designing a database 2. Design a database of students in your class. The data items should include student name, student ID, course, faculty department, hall of residence. Using the student ID, manipulate this data use on your computer screen Forum Question Describe the r ole of data design in a systems development project Slide 33

Computing Today. Boston: Mc Craw-Hill Rowley, J. (1990).

34 References Checkland, P. (1999). System Thinking, System Practice. Chiches: John Wiley. O Brien, J. A. (2003). Introduction to Information Systems: Essentials for E-Business Enterprise. Boston: Irwin O Leary, I. and O leary, T. I. (2004). Computing Today. Boston: Mc Craw-Hill Rowley, J. (1990). The Basics of Systems Analysis and Design for Information Managers. Ludin: Clive Bingley Whitten, J. et al (2000). Systems Analysis and Design Methods. 6th ed., Boston: Mc Craw-Hill Slide 34

INFS 328 Systems Analysis and Design

INFS 328 Systems Analysis and Design Session 13 Systems Analysis and Construction Tools Lecturer: Prof. Ellis Edwin Badu, Dept. of Information Studies Contact Information: eebadu@ug.edu.gh College of Education