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1 Elicitation I. 2 Why do We Need Requirements Engineering? von Neumann: “There is no sense in being precise when you don’t even know what you are talking.

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Presentation on theme: "1 Elicitation I. 2 Why do We Need Requirements Engineering? von Neumann: “There is no sense in being precise when you don’t even know what you are talking."— Presentation transcript:

1 1 Elicitation I

2 2 Why do We Need Requirements Engineering? von Neumann: “There is no sense in being precise when you don’t even know what you are talking about”

3 3 von Neumann If people do not believe that mathematics is simple, it is only because they do not realize how complicated life is.

4 4 Basic Needs for Elicitation (Questions from Polya) What is unknown? Do you know any related problem? Can you reinvent the problem?

5 5 Elicitation Elicit [Var. elicit + make it clearer + extract], make explicit, get as much information as possible to understand the object being studied.

6 6 Elicitation Identify sources of information Gather facts Communication

7 7 Identifying Sources of Information Actors in the Universe of Discourse –Clients –Users –Developers Documents Books Software Systems COTS

8 8 Who is related to the software? interested customer developers users clients Owner Especialist Hired Partner Tierd party clients Investor Quality Control (QC) Technical writers Software Engineer clients Non-clients

9 9 Criteria Experience Knowledge about the domain Volume of investment Function

10 10 Sources of Information UofD Source of Information = { a,b,c,d,e,f} U {g,h}

11 11 Heuristics to identify sources of information Who is the client? Who owns the system? Is there any customized system available? What are the books related to the application? Is it possible to reuse software artifacts? What are the documents most cited by the actors of UofD?

12 12 Abstract tree of people interested in the software CFO Accounting Acquisition Sales Revenue Manager Emplyee A Employee B requirements

13 13 Facts gathering Document Reading Observation Interviews Reunions Questionnaires Anthropology Active participation from actors Protocol Analysis Reverse Engineering Reuse

14 14 Enterviews Interviews Estructured ????? –Usually 1 to 1 –Can be 1 to n or n to 1 –Requires some knowledge about the problem to formulate the questions

15 15 Structured Interview What to ask –Objective questions with precise target –One question should be related to the other How to ask Ask whom

16 16 Non-Structured Interview More flexible Informal Mostly used during eploratory phases

17 17 Tacit Knowledge The kind of knowledge that is trivial for the actor being interviewed but not for the interviewer Because it is trivial, people almost never remebers to mention it. The interviewer in his/her turn, not knowing about the tacit knowledge can not ask about it.

18 18 Interviews + –direct contact with the actors –Can validate information immediately - –Tacit knowledge –Cultural diferences

19 19 Reading Books –Summary per chapter –Highlight the most important parts –Use a key-word index –vocabulary

20 20 Reading Macrosystem Documents (A more careful reading) –Underline repeated words –Synonymies –Take note of unknown terms –Search for relationships among terms –Vocabulary –Try to understand and document the structure of the documents

21 21 Reading Reading Similar Documents: –Identify structures –Relate structures –vocabulary

22 22 Document Reading + –Easy access to different sources of information –Volume of information - –Information can very dispersed –Considerable amount of work is required to identify relevant facts

23 23 Questionnaires What should one ask ? –Asks for some knowledge about the problem –similar to the structured interview

24 24 Questionnaires Types qualitative –Allows the one answering to further considerations –Makes a later analysis more difficult –Control questions – We can stimulate conflicts in order to verify the consistency of what is being told quantitative –grading ( Yes, No/ Good, mdeium, bad/ 0,1,2,3,4) –Question has to be well formed to allow a good distribution of the answers

25 25 Examples Quantitative 5 - XXX keeps statistical data about the software development process Number of Answers No Yes

26 26 Examples 8 – How easyly can you retrieve information from Patient’s Medical Records ? Number of Answers Not easy at all Kind of easily easily

27 27 Examples Qualitative How do you see your background regarding the development od quality software? What do you think would be necessary to improve your performance? What knowledges would like to get? Why ? –Objetive: verify the opinion regarding training policy –Why ?: A mature organization has to have well defined training policies. Control question.

28 28 Questionnaires + –Standard questions –Statistical treatment possible - –Answers are constrained –Few or no interaction/participation –Number of questionnaires returned can be disappointing

29 29 Meetings An extension of an interview or Direct and Intense participation –Short and intense periods –focus Brainstorm JAD Requirements Workshop –Uses facilitators –Previous planning

30 30 Meetings Requirements Workshop Preparation –Adequate place –Choosing Participants –Prepare the material ahead –agenda

31 31 Meetings Requirements Workshop Facilitator –Trained –Team spirit –Respected by all participants –“Powefull” “Powerfull” enough to make decisions when conflicts arise

32 32 Meetings Requirements Workshop During the meeting –relax participants –Focus on ideas not people –Conduct to a brainstorming –Register the meeting (minutes are highly desirable) –follow up e agenda for next meetings

33 33 Meetings Requirements Workshop Problems –People with a reign attitude –Passive attitude –People arriving late –Negative/mocking comments –It is always hard to resume a meeting after a disruptive interruption

34 34 Meetings Brainstorm Generate and condensate ideas Frequently, the best ideas are combinations of two or more ideas Prioritize the ideas It is better to be done locally, but it is possible to have it over the web or using video-conference

35 35 Meetings Brainstorm Phase I – Generating ideas Goal: Generate the more ideas possible Rules – Do not allow critics or debate at this point – Let the imagination flows –Change and combine ideas

36 36 Meetings Brainstorm Phase II –Reducing the number of ideas Discard ideas that are not worth to invest Group ideas – make meaningful names and group ideas according them Anotate small descriptions about the rationale regarding the ideas and its authors Prioritize –vote –categorize - critical, important, useful

37 37 Meetings JAD (Joint Application Design) Involves Objectives System Requirements External Project

38 38 Meetings Principles of JAD Group dynamic Visual resources Organized and rational process Documenting using the idea of “What you see is what you get” (WYSISYG)

39 39 Meetings JAD Target Identify high level (abstract) requirements Define and Associate the scope Plan the activities for each phase of the project Post and approve resulting documents

40 40 Meetings JAD’s Phases Customization Meetings –Present the tasks –Join ideas –Evaluate –Compromise Closing

41 41 Meetings JAD - Documents Requirements –High level requirements –Goals –Anticipated benefits –Strategies and future considerations –Hypothesis and constraints –Security, auditing and control –System scope –System users and their locations –Functional areas outside the application

42 42 Meetings JAD - Documents Plans: –Participant matrix –Identification of the JAD/PROJECT –Estimative

43 43 Meetings + –Gives the RE multiple options –Collective work - –Dispersion –Cost

44 44 Observation + –low cost –Easy task (Not always) - –Depends on the actor not being influenced because he knows he’s being observed –Depends on the observer’s skills –Tends to be superficial due to the weak exposition to the UofD

45 45 Protocol Analysis Analyze the work the person “besides” you is doing Speak loud during the tasks SOme claim one can use the memory Goal – identify the rationale used to perform a task

46 46 Protocol Analysis + –Elicit facts not shown –Better understanding about tasks and rationales behind them - –Focus on performance (not necessarily true) –Not always what I say is what I do !!!

47 47 Ethnography Deeply integrate to the environment The Analyst becomes a client or even the responsible for some tasks Slow Long Term results

48 48 Ethnography + –Focus from the inside to the outside –Contextualized - –Time –Lack of systematization

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