tailieunhanh - Lecture Software construction - Lecture 14: Usability and user interface design

After this chapter the student should have acquired the following knowledge and skills: Usability, usability engineering, why isn’t UE done regularly? benefits of UE to an organization, benefits of UE to the user, typical web-site usability problems, user centered design, GUI design is multi disciplinary. | Software Construction Lecture 14 USABILITY and USER INTERFACE DESIGN Usability What is Usability? Ease of learning Ease of use Ease of remembering Subjective satisfaction Efficiency of use Effectiveness of use Usability Engineering Usability Engineering (UE): Processes to build “Usability” into products Various methods can be used throughout the design lifecycle Methods can be incorporated into design process easily Methods maintain focus on user throughout design Why Isn’t UE Done Regularly? Developers believe it takes too long is too expensive is not critical to development they can afford to learn about user problems during “live” use Also developers may not know how to do it Benefits of UE to an Organization Reduce training costs Reduce development costs Identify and fix problems early Reduce support costs; minimize need for support personnel/help desks fixes, maintenance, upgrades Enhance organization’s reputation - positive “word-of-mouth” trade Larger numbers of “hit” and “return visit” rates Benefits of UE to the User Less time to complete work Greater success with tasks Increased user satisfaction “The fun theory” Typical Web-site Usability Problems Navigation Knowing where you are Finding what you want Structure of web site Layout Needs sufficient white space Use of large graphics “The Google problem” User Centered Design UCD is a dialog between the customer and the designer Rules of thumb: Get to know and understand the users. Build an application, applying usability principles. Test designs by observing users in a real work setting (environment and work load). Usability Principles Mini-Exercise Apply the principles to a web-site of your choosing, or try: GUI Design is Multi Disciplinary A team includes Analyst Designer Technology expert Graphic artist Social and behavioral scientist Programmer Basic Principles Assume users Have not read the manual Have not attended training Do not have external help readily at hand So All controls should be clear and understandable and placed in an intuitive location on the screen. Usability Design Process Use Scenario Development You already know about use cases Use scenarios are just a single thread through a use case – much simpler! UI Structure/Flow of Control