Asper School of Business University of Manitoba.ppt

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1、Asper School of Business University of Manitoba,Systems Analysis & Design,Instructor: Bob Travica,Determining system requirements,Updated: September 2018,3510 Systems Analysis & Design * Bob Travica,2 of 14,Outline,Requirements determination = system analysis activity done by a system analyst Concep

2、t of system requirement Modeling requirements via diagrams Requirements gathering methods(Interviewing, Focus Groups, Observation,ThinkAloud Protocol, Joint Application Design,Survey),3510 Systems Analysis & Design * Bob Travica,3 of 14,Requirements activity in SDLC,System is analyzed - requirements

3、 are collected - in each iteration; most of it is in the Elaboration phase.Requirements activity precedes design, implementation, testing In the end of each iteration (a column) is working software, whose development can be continued later.,3510 Systems Analysis & Design * Bob Travica,4 of 14,System

4、s analysts job,Define & document system requirements (functional & non-functional): Investigate user needs (interview, etc.) Understand business (application domain) Study existing system (hands-on, documentation, inputs/outputs) Study benchmark systems Create diagrams & descriptions to capture requ

5、irementsthat will translate into systems data model and functionality Model user interface,3510 Systems Analysis & Design * Bob Travica,5 of 14,System Requirements,Functional: Specification of tasks system should perform (e.g., calculate pay)Non-functional: User interface (e.g., ease of use) Technic

6、al performance (e.g., execution speed, reliability) Security,3510 Systems Analysis & Design * Bob Travica,6 of 14,Object-oriented diagrams,Activity Diagram,3510 Systems Analysis & Design * Bob Travica,7 of 14,Requirements gathering methods,Interviewing Focus Groups Observation ThinkAloud Protocol Jo

7、int Application Design Survey,3510 Systems Analysis & Design * Bob Travica,8 of 14,Interviewing,Data collection through talking with users,Natural, pervasive, basic method,Considerations:Communication issuesLevel of structuring (open-ended vs. close-ended)Time expenditures,Advantages: Can provide sp

8、ecific & rich account of needs,Challenges: Striking a right balance between considerations,Good example: Consultants developing custom software, multiple visits, working with clientBad example: Too short interviewing, biased user samples, inappropriate outsourcing of interviewing task,3510 Systems A

9、nalysis & Design * Bob Travica,9 of 14,Interviewing example,3510 Systems Analysis & Design * Bob Travica,10 of 14,Focus Groups,Group interviewing with many interviewers,Origin: Marketing research,Considerations: Discussion focus Time distribution (talkative vs. silent interviewees),Advantages: Deep

10、initial insight in user situation.,Challenges: Managing group dynamics,3510 Systems Analysis & Design * Bob Travica,11 of 14,Observation,Collecting data by watching, listening and asking spontaneousquestions with various degrees of the observers visibility.,Considerations: Involvement in user situat

11、ionSubjectivityObtrusiveness,Advantages: Learning in natural context, rich in detail.,Challenges: Hawthorne effect (negative effect from obtrusiveness), validity of conclusions,3510 Systems Analysis & Design * Bob Travica,12 of 14,Think-Aloud Protocol,Recording users thoughts they speak aloud while

12、performinga task with a system; “short memory “dump”,Considerations: Relaxing the user to talking along with doing (not a natural behavior),Advantages: Insight in users short-term memory thatotherwise may be lost,Challenges: Users account may be narrow and not reflexive (thought-through),Can be comb

13、ined with observation (in usability study),Example Simulation systems for risky situations (pilots)Example Lack of prompting users to speak,3510 Systems Analysis & Design * Bob Travica,13 of 14,Survey,Collecting mostly quantitative data by administering a questionnaire (mail, or electronic).,Conside

14、rations: Limitations of written communication,Advantages: Specific coverage and time savings, electronictrail (direct entry of answers to database),Challenges: Validity of users responses and lower response rates,Example Quick probing a general feeling about an existing system & a need for new sys.

15、User satisfaction.Example Asking too specific & too many questions, anonymity issue,3510 Systems Analysis & Design * Bob Travica,14 of 14,Joint Application Design,A JAD Facility,Discussion in a small group (designated team, committee) to define system requirements. Made for waterfall methodologybut may be iterative. Example: IBM,