Kiến trúc máy tính và hợp ngữ - Chapter 3: Software elicitation

What is Requirement Elicitation? Participants in elicitation Risks of requirements elicitation Requirements elicitation techniques The most common causes of poor quality, cost overruns and late delivery of software: Incorrect, incomplete, or misunderstood requirement Requirements elicitation is “the process of discovering the requirements for a system by communicating with customers, system users and others who have a stake in the system development” Gather requirement from various sources: identify requirement providers: stakeholders Analyse the gathered information, looking for implications, inconsistencies or unresolved issues Confirm understanding of the requirements with the users Synthesize appropriate statements of the requirements Requirement elicitation involves many people. Customer/Client: Person who pays for the software development. Ultimately, has the final word on what will be the product Software engineer: Expert who knows the technology and process -> produce the requirements specifications The potential users: of the current system or future systems  indicate which functions to maintain or improve Articulation problems: The user can’t express their needs The users may not aware of their needs or not understand how the technology may be able to help them The user may aware of a need but be afraid of express it. Users and developers misunderstand concepts or relationships because they have different meanings for common terms(ex:implementation) Communication Barriers: Users and developers come from different worlds and have different professional vocabularies The users have different concerns from those of developer (high-level attributes vs low-level technical issues) Different personality types and different value systems among people Knowledge and cognitive limitations The users and developers don’t have enough domain or technical knowledge The users and developers don’t remember exactly what was said  may misinterpret that information late Try to simplify the propblem or ignore parts of problem  distort the problem State the problem in terms of favored solution Human behavior issues: Requirement elicitations is a social process  human behavior issues are involved Conficts and ambiguities in the roles of stakeholders  lead to gap in requirements Fear the new system will necessitate the changes in behavior of individuals and group  withhold information Technical issues The problems are becoming increasingly complex Requirements change over time There are many sources of requirements.. Asking Observing and inferring Discussing and formulating Negotiating Studying and identifying problems Discovering through creative process Interview Brainstorming JAD Prototype The most commonly used requirements gathering technique. Three main objectives: Record information to be used as input to requirements analysis and modeling Discover information from interviewee accurately and efficiently Reassure interviewee that his/her understanding of the topic has been explored, listened to, and valued Process consists of three important steps: Planning and preparation Conducting the interview Postinterview follow-up. Planning and preparation Set goals and objectives for the interview Select interviewees Create an interview schedule Designing Interview Questions Closed-Ended Questions Opened-Ended Questions Probing Questions Conducting the interview Make the interviewee comfortable and confident Be polite and respectful! Take careful notes Don’ t afraid to ask Postinterview follow-up Prepare an interview report that describes the information from the interview. Send the interview report to the interviewee with a request to read it and inform the analyst of clarifications or updates. Problem solving stages includes: Problem Identification Idea Generation Idea Selection (decision making) Implementation Brainstorming requires multiple people, the Project Manager functions as a facilitator of the session Two main activities: The Storm: Generating as many ideas as possible (quantity, not quality) – wild is good! Idea Selection : Filtering out of ideas (combine, clarify, prioritize, improve) to keep the best one(s) – may require some voting strategy Planning the Session Define the problem Identify participants Create groups out of the participants (just 3-4 members/group). Each group should consist of people from diverse and relevant backgrounds Conducting the Session After the Brainstorming Session Give a reward or recognize the participant follow-up and monitor the solution to closure. An information gathering technique that allows the project team, users, and management to work together to identify requirements for the system JAD is a structured process 10 to 20 users meet together under the direction of facilitator skilled in JAD techniques. Preparation Pre-session Planning Pre-work Conduction the JAD session Summary Pre-session Planning Evaluate project Identify contentious issues and scope of JAD session Select JAD participants Create preliminary agenda Determine deliverables for the working session Enable participants to prepare for the session Pre-work Planning Gather information Clear schedules for the working session Refine session agenda Finalize pre-session assignments Prepare material for session (flip-charts, presentations, marker...) Set-up stage Session leader welcomes participants, presents task to be discussed, establishes rules and what is on/off topic Generate common understanding Achieve agreement on decisions Create the deliverables Identify open issues and questions Follow-up Resolve open issues and questions Evaluate the JAD process Follow-up on action items Re-evaluate project Discuss "lessons learned" Finalize deliverables Facilitator - JAD expert Good with people skills, enthusiastic, sets tone of meeting Set the meeting agenda and guide the discussion Do not join in the discussion as a participant - do not provide ideas or opinions on the topics under discussion to remain neutral during the session. Must be an expert in both group process techniques and systems analysis and design techniques. Others: Executive sponsor User representatives Information system representatives Specialists A new form of JAD called electronic JAD or e-JAD Each participant uses special software on a networked computer to send anonymous ideas and opinions to everyone else. All participants can contribute at the same time, without fear of reprisal from people with differing opinions. A software requirements prototype is a model or partial implementation of a software system. Helps developers, users, and customers better understand system requirements Helps clarify and complete requirements Helps find new functionalities, discuss usability, and establish priorities Prototyping is effective in resolving uncertainties early in the development process Focus prototype development on these uncertain parts Encourages user participation and mutual understanding Prototypes that focus on user-interface tends to lose the focus of demonstrating/exploring functionality Prototypes can bring customers’ expectations about the degree of completion unrealistically up Do not end-up considering a throwaway prototype as part of the production system Always clearly state the purpose of each prototype before building it