Analysis vs. Design Stage

• During requirement analysis stage– What is the problem?– What can be improved?– What does the user wants?– What are the services & constraints of the system?

• During design stage– How will the system be designed to meet user

requirements?– How will the user interface look like?– How will the database (files) be designed?

Design stages

1. Identify the objective of the new system – Functional and non-functional requirements– Described in measurable way

2. Develop alternatives to achieve objectives– Decide on design strategies

3. Decide the most feasible solution4. Update project plan and budget5. Describe the design of the new system

– Design parts

Issues to Consider for Design Strategies

2.1 Sources of software2.2 Implementation issues

– Installation of software– Training– Data migration– Changes to the business process and relations

2.3 Buying off- the-shelf software2.4 Consider current hardware and software

– You may need to upgrade your hardware, network and software environment for a new system

Sources of Software

2.1.1 Outsourcing: giving the responsibility of running or developing part or all of the information system to an outside organization

2.1.2 Hardware manufacturers

2.1.3 Off-the-shelf software (generic systems)

2.1.4 Custom software producers

2.1.5 Application service provider

2.1.6 Enterprise software solutions

2.1.7 In-house development

Buying Off-The-Shelf Software

• Criteria to consider when buying– Cost -software functionality– Documentations - Vendor support & viability– Software quality (reliability, usability, security, efficiency..)– Ease of integration with the environment

• Sources of information for evaluation– Vendor information (Request for bid)– General publications that makes comparisons between

software – Trial versions– Reference to customers

Decide the Best Alternative

3.1 List essential requirements and constraints

3.2 Give weights according to importance

3.3 List alternatives

3.4 Rate each alternative on a scale (1-5) for ech criteria

3.5 Calculate the score for each alternative

3.6 Decide on the best solution

Design Parts

• Software packaging design – Architecture design – Component design – Data structure design– Algorithm design

• User interface design

• Database and file design

User interface design

• The importance of user interface design– Users judge the software based on its user interface– Good design make the SW easy to use and reduce

training time.– Poor design can cause the user to make errors– Poor interface is the reason why SW are never used

• User interface is divided into – User interaction (input)– Information presentation (output)

User interface design principles

Principle Description

User familiarity The interface should use terms and concepts which are drawn from the experience of the user

Consistency Comparable operations should be activated in the same way

Minimal surprise Users should never be surprised by the behaviour of the system

Recoverability The interface should include mechanism to allow users to recover from their errors

User guidance The interface should incorporate some form of context sensitive user guidance and assistance

User Interface design

• Design considerations– User needs and experience– System needs– Human capabilities

• During the UI design, prototypes should be produced and user feedback should be collected

Types of User Interfaces

• Command– Not user friendly, a lot of memorization– Good for experienced users

• Menus (options)– Either text based or pull down menu– Good for inexperienced

• Question & Answer (wizard dialogs)– Reduce the complexity of achieving a process– Good for novice users

Types of User Interfaces• Graphical User Interface

– Direct manipulation of graphical representations– Provides continues feedback (drag & drop)– Uses metaphors & meaningful icons

• Icons are pictorial on screen representations which symbolize a computer action

• Easy to understand

• Be consistent in meanings

– Good for novice users

• Natural Language (text based)– Use simple English to process data

• Touch screens & voice recognition

User interface evaluation

• Some evaluation of the user interface design should be carried out to assess its usability

• Simple evaluation methods:– Questionnaires for user feedback– Video recording of system use– System code collects information about user errors – Observation of users at work

User guidance

• The user guidance is integrated with the user interface to help users when they need information about the system or when they make some error

• User guidance includes:– System messages, including error messages– Documentation provided for users (user manual,

multi-entry help tree, installation instructions, system administration instructions)

– On-line help

User guidance

• Always give the user feedback confidence

• Give feedback in the following situations:– Acceptable input format– Report processing delay– Process is completed– Unacceptable input

• Use clear & polite messages, suggest an action

• Don’t use beeps or sound (embarrassing)

User Interface design

• Color – Use it to indicate error

– Can be used to highlight important information

– Adds an extra dimension to the interface and help the user understand complex structures

• Guidelines for using color– Use matching colors

– Provide a color key when using it as an extra dimension

– Do NOT use more than 4 colors

– Be careful with law resolution screens

Output design

• Types of output– External (targeted to people outside the organization)

• Put instructions on how to use, company logo, company contact info.

– Internal (used within the organization)

• Output technologies– Printers - Microfilm

– Screen - CD- ROM

– Audio - Electronic output

• Output technologies differ in their speed, cost, portability, flexibility, storage and retrieval possibilities

Output design

• Guidelines for good output design– Consider the user (non computer professional, disabled,

remote, .. etc)

– Serve the intended purpose– Present the output on time– Deliver the appropriate amount of output (clutter)– Choose the output method according to content

• Printed, screen, audio, CD and DVD, Microfilm, distributed electronic output (email, web site, fax)

Output Methods

• Criteria to choose the output technology– Who will see the output?

– How many users?

– User distribution

– Purpose of the output

– How fast does the user need the output?

– How frequent does the user need the output?

– How long will it be stored?

– Legislation

– Initial and maintenance cost

Output Design

• Output can affect the user in the wrong way, which creates a source of bias.– Information sorting (alphabetically, higher marks)– Size, and colors of graphs and tables– Acceptable limits used in the system

• Solutions– Tell the user about sources of bias– Give the user the ability to change output format– Use prototypes to reach the best design with the user

Input design• Input types:

– Manual forms– Screen or web forms

• Objectives of input design– Effective: input should serve the purpose– Consistency: similar processes invoked by similar actions– Accuracy: prevent the user from doing mistakes– Ease of use & simplicity: clear, not cluttered & no need for

extra help– Attractive: input should be interesting to use– No duplication in data collection

Input design• Guidelines to make forms easy to fill

– Logical flow of information– Three parts of input form (heading, body, end)– Clear caption– Provide instructions– Multi-purpose forms (duplication of information)

• Guidelines for screen forms– Simple and consistent (don’t clutter)– Provide help and examples – Facilitate user movement among screens (scrolling, call another

window for more details, hyperlinks)– Attractive ( use color, boxes and different fonts)

Web Site Design

• Number of web pages ordered, designed and maintained together

• How to design good web sites:– Use authoring tools to help you– Look at other web sites (good & bad)– Use resources on the web (texture, images,gif,..)– Consistency of design– Be careful with download time – Avoid using technologies that require plug-ins– Plan your web site

Web Site Guidelines

• Structure– Web pages are linked together (use a tree diagram)

– Each page has a message (main page to link)

• Content– What are you trying to say?

– Provide interaction, attractive material & update them

• Text– Title and text words should reflect content (search engines)

Web Site Guidelines

• Graphics– Use simple background color or texture– Small size images (GIF, JPEG)– Test your pages on different browsers & monitors

• Presentation– Entry page, links to other pages– Avoid too much multimedia, blinking & animation– Don’t clutter the screen– Theme of the web site

Web Site Guidelines• Navigation

– Keep a roadmap of the options available all the time– Download time specially first page (entry image !!)– Give the user the information they want at first

• Promotion– Register in search engines– Put exciting & dynamic information– Maintain the web site (modified date)

• Input forms– Use the right control to input data– Give clear instructions on how to fill– Use clear captions (optional & mandatory fields)– Use scripts to validate user input