User Interfaces 4 BTECH: IT WIKI PAGE:

Topic 3 Design Processes USCD analysed Key activities Hierarchical task analysis Requirement gathering

USCD analysed Methods Waterfall Model design Iterative Model design V- Model design Big Bang Model design and Application Agile RAD Software Prototyping

Waterfall Model design This diagram and following pages taken from

Iterative Model design Iterative process starts with a simple implementation of a subset of the software requirements and iteratively enhances the evolving versions until the full system is implemented. At each iteration, design modifications are made and new functional capabilities are added. The basic idea behind this method is to develop a system through repeated cycles (iterative) and in smaller portions at a time (incremental).

V- Model design

Big Bang Model design and Application Big bang model consists of focusing all the possible resources in software development and coding, with very little or no planning. The requirements are understood and implemented as they come. Any changes required may or may not need to revamp the complete software. This model is ideal for small projects with one or two developers working together and is also useful for academic or practice projects. It’s an ideal model for the product where requirements are not well understood and the final release date is not given.

Agile

RAD

Software Prototyping Basic Requirement Identification Developing the initial Prototype Review of the Prototype Revise and enhance the Prototype Good for systems having high level of user interactions e.g. online systems. Not good when too much data processing and most of the functionality is internal not good

Weaknesses It is assumed that the users can specify their requirements precisely at the beginning, and will not change them as the development process proceeds All knowledge of the implementation of the existing system is discarded No attention is paid to the mechanisms through which the steps can be carried out, the assumption being that they are logical and obvious.

User Centred Design Understand the context of use: look at the characteristics (including language and literacy levels) of the users, their tasks and environment. Involve users in the design process frequently: do usability tests. Use iteraterative design solutions: refine designs and prototypes step by step, based on user feedback. Integrate User Centred Design in all development steps. Use existing knowledge: apply existing Human Computer Interaction guidelines.

Key Activities of UCD Task analysis Requirements gathering Design and Storyboarding Prototyping Evaluation and Installation

Task Analysis Description of tasks when interacting with the system (goals) Description of process of interaction when completing the tasks (actions) Before changes to the stem are made What skills and abilities are needed Most commonly used: hierarchy Contribute towards a better understanding of requirements Written in simple language, cover both tasks and users

Approaches to Task Analysis Focus on: Goals and actions (procedures and methods) What users know bout their work and tasks Psychological processes Objects and entities o which users will act Objects and attributes Inputs Problem statement Observations Analysis of users

Task Analysis continued Output Profile of users Diversity of population Improvements to provide universal acess Reasons why users don’t like/use the existing system Review design

Data collection methods Observation Interviews, focus groups, informal talks Existing documentations and manuals Do task yourself Get to know existing system (manual or computerised)analyse real tasks Conduct experiments Inquiry methods Triangulation: more than one method to obtain results Task Analysis continued

Example: cash withdrawal from ATM 0withdraw ash 1Check whether machine works o Status indicator o Card logo 2Insert card 3Choose language 4Enter pin 5Initiate withdrawal o Select withdraw cash o Enter amount 6Complete transaction 6Take card 7Take cash

Exercise Do a task analysis of how to send an sms using your cell phone

Requirement Gathering User models Paper modelling Task analysis Existing system: documents, manuals Surveys: online suggestions, trouble reporting Interviews, interactive Focus group discussions Online bulletin board News letters

Design Identify design space: question, option, criteria o E.g. Q: How do you support database query for novices? o O1: query by pointing from displayed lists o O2 : Query via virtual reality library metaphor o Criteria: ….hide complexities of SQL from user Storyboarding: relate design to requirements

Prototyping Techniques Rapid prototyping: quick look and feel of system, LaTeX High fidelity vs low fidelity Horizontal and vertical: wide range vs small subset greater depth of functionality Wizard of Oz: connect user machine with designer, team members controls system outputs and responses. Limited functionality simulation: database mock up, credit card responses.