Suche senden
Hochladen
Software Engineering - Ch7
•
14 gefällt mir
•
8,366 views
S
Siddharth Ayer
Folgen
Technologie
Business
Melden
Teilen
Melden
Teilen
1 von 52
Jetzt herunterladen
Downloaden Sie, um offline zu lesen
Empfohlen
Requirements Engineering Processes in Software Engineering SE6
Requirements Engineering Processes in Software Engineering SE6
koolkampus
Software Development Life Cycle
Software Development Life Cycle
Slideshare
Deploying java beans in jsp
Deploying java beans in jsp
Priyanka Pradhan
Taxonomy for bugs
Taxonomy for bugs
Harika Krupal
Software Engineering ppt
Software Engineering ppt
shruths2890
Testing strategies in Software Engineering
Testing strategies in Software Engineering
MuhammadTalha436
Software quality management lecture notes
Software quality management lecture notes
AVC College of Engineering
Software Process Models
Software Process Models
Hassan A-j
Empfohlen
Requirements Engineering Processes in Software Engineering SE6
Requirements Engineering Processes in Software Engineering SE6
koolkampus
Software Development Life Cycle
Software Development Life Cycle
Slideshare
Deploying java beans in jsp
Deploying java beans in jsp
Priyanka Pradhan
Taxonomy for bugs
Taxonomy for bugs
Harika Krupal
Software Engineering ppt
Software Engineering ppt
shruths2890
Testing strategies in Software Engineering
Testing strategies in Software Engineering
MuhammadTalha436
Software quality management lecture notes
Software quality management lecture notes
AVC College of Engineering
Software Process Models
Software Process Models
Hassan A-j
Software Testing and Quality Assurance Assignment 3
Software Testing and Quality Assurance Assignment 3
Gurpreet singh
Chapter 01 software engineering pressman
Chapter 01 software engineering pressman
RohitGoyal183
Integration test
Integration test
sadegh salehi
Requirement Elicitation Techniques
Requirement Elicitation Techniques
Shwetha-BA
Types of testing
Types of testing
Sonam Agarwal
Testing concepts ppt
Testing concepts ppt
Rathna Priya
Convert ER diagram to Relational model and Normalization
Convert ER diagram to Relational model and Normalization
Saadi Rahman
Structured Vs, Object Oriented Analysis and Design
Structured Vs, Object Oriented Analysis and Design
Motaz Saad
Requirements Engineering Processes
Requirements Engineering Processes
Ra'Fat Al-Msie'deen
Comparison of the Waterfall, Spiral, and Prototype SDLC Models
Comparison of the Waterfall, Spiral, and Prototype SDLC Models
Teresa Rothaar
SQE Lecture 1.pptx
SQE Lecture 1.pptx
UsmanShafique23
ppt on sOFTWARE DEVELOPMENT LIFE CYCLE
ppt on sOFTWARE DEVELOPMENT LIFE CYCLE
Swarnima Tiwari
Software Testing - Defect/Bug Life Cycle - Complete Flow Chart of Defect States
Software Testing - Defect/Bug Life Cycle - Complete Flow Chart of Defect States
eVideoTuition
The four generations of test automation
The four generations of test automation
renard_vardy
Software Engineering Process Models
Software Engineering Process Models
Satya P. Joshi
Software development life cycle (SDLC)
Software development life cycle (SDLC)
Simran Kaur
Software Devlopment Life Cycle
Software Devlopment Life Cycle
Vivek Gupta
Requirement engineering evaluation
Requirement engineering evaluation
Ishraq Al Fataftah
Requirements Engineering Process Improvement
Requirements Engineering Process Improvement
Ian Sommerville
ISTQB Foundation Level Basic
ISTQB Foundation Level Basic
Selin Gungor
Software Engineering - Ch4
Software Engineering - Ch4
Siddharth Ayer
Software Engineering - Ch6
Software Engineering - Ch6
Siddharth Ayer
Weitere ähnliche Inhalte
Was ist angesagt?
Software Testing and Quality Assurance Assignment 3
Software Testing and Quality Assurance Assignment 3
Gurpreet singh
Chapter 01 software engineering pressman
Chapter 01 software engineering pressman
RohitGoyal183
Integration test
Integration test
sadegh salehi
Requirement Elicitation Techniques
Requirement Elicitation Techniques
Shwetha-BA
Types of testing
Types of testing
Sonam Agarwal
Testing concepts ppt
Testing concepts ppt
Rathna Priya
Convert ER diagram to Relational model and Normalization
Convert ER diagram to Relational model and Normalization
Saadi Rahman
Structured Vs, Object Oriented Analysis and Design
Structured Vs, Object Oriented Analysis and Design
Motaz Saad
Requirements Engineering Processes
Requirements Engineering Processes
Ra'Fat Al-Msie'deen
Comparison of the Waterfall, Spiral, and Prototype SDLC Models
Comparison of the Waterfall, Spiral, and Prototype SDLC Models
Teresa Rothaar
SQE Lecture 1.pptx
SQE Lecture 1.pptx
UsmanShafique23
ppt on sOFTWARE DEVELOPMENT LIFE CYCLE
ppt on sOFTWARE DEVELOPMENT LIFE CYCLE
Swarnima Tiwari
Software Testing - Defect/Bug Life Cycle - Complete Flow Chart of Defect States
Software Testing - Defect/Bug Life Cycle - Complete Flow Chart of Defect States
eVideoTuition
The four generations of test automation
The four generations of test automation
renard_vardy
Software Engineering Process Models
Software Engineering Process Models
Satya P. Joshi
Software development life cycle (SDLC)
Software development life cycle (SDLC)
Simran Kaur
Software Devlopment Life Cycle
Software Devlopment Life Cycle
Vivek Gupta
Requirement engineering evaluation
Requirement engineering evaluation
Ishraq Al Fataftah
Requirements Engineering Process Improvement
Requirements Engineering Process Improvement
Ian Sommerville
ISTQB Foundation Level Basic
ISTQB Foundation Level Basic
Selin Gungor
Was ist angesagt?
(20)
Software Testing and Quality Assurance Assignment 3
Software Testing and Quality Assurance Assignment 3
Chapter 01 software engineering pressman
Chapter 01 software engineering pressman
Integration test
Integration test
Requirement Elicitation Techniques
Requirement Elicitation Techniques
Types of testing
Types of testing
Testing concepts ppt
Testing concepts ppt
Convert ER diagram to Relational model and Normalization
Convert ER diagram to Relational model and Normalization
Structured Vs, Object Oriented Analysis and Design
Structured Vs, Object Oriented Analysis and Design
Requirements Engineering Processes
Requirements Engineering Processes
Comparison of the Waterfall, Spiral, and Prototype SDLC Models
Comparison of the Waterfall, Spiral, and Prototype SDLC Models
SQE Lecture 1.pptx
SQE Lecture 1.pptx
ppt on sOFTWARE DEVELOPMENT LIFE CYCLE
ppt on sOFTWARE DEVELOPMENT LIFE CYCLE
Software Testing - Defect/Bug Life Cycle - Complete Flow Chart of Defect States
Software Testing - Defect/Bug Life Cycle - Complete Flow Chart of Defect States
The four generations of test automation
The four generations of test automation
Software Engineering Process Models
Software Engineering Process Models
Software development life cycle (SDLC)
Software development life cycle (SDLC)
Software Devlopment Life Cycle
Software Devlopment Life Cycle
Requirement engineering evaluation
Requirement engineering evaluation
Requirements Engineering Process Improvement
Requirements Engineering Process Improvement
ISTQB Foundation Level Basic
ISTQB Foundation Level Basic
Andere mochten auch
Software Engineering - Ch4
Software Engineering - Ch4
Siddharth Ayer
Software Engineering - Ch6
Software Engineering - Ch6
Siddharth Ayer
Software Engineering - Ch11
Software Engineering - Ch11
Siddharth Ayer
Software Engineering - Ch1
Software Engineering - Ch1
Siddharth Ayer
software engineering
software engineering
ramyavarkala
Software Engineering - Ch8
Software Engineering - Ch8
Siddharth Ayer
software engineering notes for cse/it fifth semester
software engineering notes for cse/it fifth semester
rajesh199155
Architectural patterns for real-time systems
Architectural patterns for real-time systems
sommerville-videos
Software engineering lecture notes
Software engineering lecture notes
Siva Ayyakutti
Software engineering presentation
Software engineering presentation
MJ Ferdous
Andere mochten auch
(10)
Software Engineering - Ch4
Software Engineering - Ch4
Software Engineering - Ch6
Software Engineering - Ch6
Software Engineering - Ch11
Software Engineering - Ch11
Software Engineering - Ch1
Software Engineering - Ch1
software engineering
software engineering
Software Engineering - Ch8
Software Engineering - Ch8
software engineering notes for cse/it fifth semester
software engineering notes for cse/it fifth semester
Architectural patterns for real-time systems
Architectural patterns for real-time systems
Software engineering lecture notes
Software engineering lecture notes
Software engineering presentation
Software engineering presentation
Ähnlich wie Software Engineering - Ch7
Ch7
Ch7
phanleson
5. SE RequirementEngineering task.ppt
5. SE RequirementEngineering task.ppt
HaiderAli252366
Ch6
Ch6
phanleson
SRE.pptx
SRE.pptx
KalsoomBajwa
Lecture10.ppt
Lecture10.ppt
WasekaPropertyportal
Unit2 Software engineering UPTU
Unit2 Software engineering UPTU
Mohammad Faizan
software recq.ppt
software recq.ppt
karinaabyys
Requirementengg
Requirementengg
Prof.Dharmishtha R. Chaudhari
3. 1 req elicitation
3. 1 req elicitation
Ashenafi Workie
UNIT-II MMB.pptx
UNIT-II MMB.pptx
sayalishivarkar1
REQUIREMENT ENGINEERING
REQUIREMENT ENGINEERING
Saqib Raza
Requirements Engineering for LSCITS
Requirements Engineering for LSCITS
Ian Sommerville
Lecture_three_Requirements_analysis.pptx
Lecture_three_Requirements_analysis.pptx
GracePeter10
Requirements Engineering
Requirements Engineering
MuhammadTalha436
Requirements engineering
Requirements engineering
Sutha31
Reqmt_Engn.ppt
Reqmt_Engn.ppt
DrCMeenakshiVISTAS
Wireless communication.ppt
Wireless communication.ppt
ssuser183d67
Requirement Engineering.pdf
Requirement Engineering.pdf
Muhammad Imran
WINSEM2021-22_ITE2004_ETH_VL2021220500452_Reference_Material_I_03-01-2022_Sof...
WINSEM2021-22_ITE2004_ETH_VL2021220500452_Reference_Material_I_03-01-2022_Sof...
madhurpatidar2
Software Requirements.pptx
Software Requirements.pptx
Prem Chandrakar
Ähnlich wie Software Engineering - Ch7
(20)
Ch7
Ch7
5. SE RequirementEngineering task.ppt
5. SE RequirementEngineering task.ppt
Ch6
Ch6
SRE.pptx
SRE.pptx
Lecture10.ppt
Lecture10.ppt
Unit2 Software engineering UPTU
Unit2 Software engineering UPTU
software recq.ppt
software recq.ppt
Requirementengg
Requirementengg
3. 1 req elicitation
3. 1 req elicitation
UNIT-II MMB.pptx
UNIT-II MMB.pptx
REQUIREMENT ENGINEERING
REQUIREMENT ENGINEERING
Requirements Engineering for LSCITS
Requirements Engineering for LSCITS
Lecture_three_Requirements_analysis.pptx
Lecture_three_Requirements_analysis.pptx
Requirements Engineering
Requirements Engineering
Requirements engineering
Requirements engineering
Reqmt_Engn.ppt
Reqmt_Engn.ppt
Wireless communication.ppt
Wireless communication.ppt
Requirement Engineering.pdf
Requirement Engineering.pdf
WINSEM2021-22_ITE2004_ETH_VL2021220500452_Reference_Material_I_03-01-2022_Sof...
WINSEM2021-22_ITE2004_ETH_VL2021220500452_Reference_Material_I_03-01-2022_Sof...
Software Requirements.pptx
Software Requirements.pptx
Mehr von Siddharth Ayer
Software Engineering - Ch12
Software Engineering - Ch12
Siddharth Ayer
Software Engineering - Ch9
Software Engineering - Ch9
Siddharth Ayer
Software Engineering - Ch5
Software Engineering - Ch5
Siddharth Ayer
Software Engineering - Ch3
Software Engineering - Ch3
Siddharth Ayer
Software Engineering - Ch2
Software Engineering - Ch2
Siddharth Ayer
Software Engineering - Ch17
Software Engineering - Ch17
Siddharth Ayer
Mehr von Siddharth Ayer
(6)
Software Engineering - Ch12
Software Engineering - Ch12
Software Engineering - Ch9
Software Engineering - Ch9
Software Engineering - Ch5
Software Engineering - Ch5
Software Engineering - Ch3
Software Engineering - Ch3
Software Engineering - Ch2
Software Engineering - Ch2
Software Engineering - Ch17
Software Engineering - Ch17
Kürzlich hochgeladen
Breaking the Kubernetes Kill Chain: Host Path Mount
Breaking the Kubernetes Kill Chain: Host Path Mount
Puma Security, LLC
EIS-Webinar-Prompt-Knowledge-Eng-2024-04-08.pptx
EIS-Webinar-Prompt-Knowledge-Eng-2024-04-08.pptx
Earley Information Science
08448380779 Call Girls In Civil Lines Women Seeking Men
08448380779 Call Girls In Civil Lines Women Seeking Men
Delhi Call girls
Strategies for Unlocking Knowledge Management in Microsoft 365 in the Copilot...
Strategies for Unlocking Knowledge Management in Microsoft 365 in the Copilot...
Drew Madelung
Partners Life - Insurer Innovation Award 2024
Partners Life - Insurer Innovation Award 2024
The Digital Insurer
Neo4j - How KGs are shaping the future of Generative AI at AWS Summit London ...
Neo4j - How KGs are shaping the future of Generative AI at AWS Summit London ...
Neo4j
Salesforce Community Group Quito, Salesforce 101
Salesforce Community Group Quito, Salesforce 101
Paola De la Torre
TrustArc Webinar - Stay Ahead of US State Data Privacy Law Developments
TrustArc Webinar - Stay Ahead of US State Data Privacy Law Developments
TrustArc
From Event to Action: Accelerate Your Decision Making with Real-Time Automation
From Event to Action: Accelerate Your Decision Making with Real-Time Automation
Safe Software
Unblocking The Main Thread Solving ANRs and Frozen Frames
Unblocking The Main Thread Solving ANRs and Frozen Frames
Sinan KOZAK
Top 5 Benefits OF Using Muvi Live Paywall For Live Streams
Top 5 Benefits OF Using Muvi Live Paywall For Live Streams
Roshan Dwivedi
Data Cloud, More than a CDP by Matt Robison
Data Cloud, More than a CDP by Matt Robison
Anna Loughnan Colquhoun
IAC 2024 - IA Fast Track to Search Focused AI Solutions
IAC 2024 - IA Fast Track to Search Focused AI Solutions
Enterprise Knowledge
🐬 The future of MySQL is Postgres 🐘
🐬 The future of MySQL is Postgres 🐘
RTylerCroy
How to convert PDF to text with Nanonets
How to convert PDF to text with Nanonets
naman860154
The Codex of Business Writing Software for Real-World Solutions 2.pptx
The Codex of Business Writing Software for Real-World Solutions 2.pptx
Malak Abu Hammad
[2024]Digital Global Overview Report 2024 Meltwater.pdf
[2024]Digital Global Overview Report 2024 Meltwater.pdf
hans926745
04-2024-HHUG-Sales-and-Marketing-Alignment.pptx
04-2024-HHUG-Sales-and-Marketing-Alignment.pptx
HampshireHUG
Presentation on how to chat with PDF using ChatGPT code interpreter
Presentation on how to chat with PDF using ChatGPT code interpreter
naman860154
Raspberry Pi 5: Challenges and Solutions in Bringing up an OpenGL/Vulkan Driv...
Raspberry Pi 5: Challenges and Solutions in Bringing up an OpenGL/Vulkan Driv...
Igalia
Kürzlich hochgeladen
(20)
Breaking the Kubernetes Kill Chain: Host Path Mount
Breaking the Kubernetes Kill Chain: Host Path Mount
EIS-Webinar-Prompt-Knowledge-Eng-2024-04-08.pptx
EIS-Webinar-Prompt-Knowledge-Eng-2024-04-08.pptx
08448380779 Call Girls In Civil Lines Women Seeking Men
08448380779 Call Girls In Civil Lines Women Seeking Men
Strategies for Unlocking Knowledge Management in Microsoft 365 in the Copilot...
Strategies for Unlocking Knowledge Management in Microsoft 365 in the Copilot...
Partners Life - Insurer Innovation Award 2024
Partners Life - Insurer Innovation Award 2024
Neo4j - How KGs are shaping the future of Generative AI at AWS Summit London ...
Neo4j - How KGs are shaping the future of Generative AI at AWS Summit London ...
Salesforce Community Group Quito, Salesforce 101
Salesforce Community Group Quito, Salesforce 101
TrustArc Webinar - Stay Ahead of US State Data Privacy Law Developments
TrustArc Webinar - Stay Ahead of US State Data Privacy Law Developments
From Event to Action: Accelerate Your Decision Making with Real-Time Automation
From Event to Action: Accelerate Your Decision Making with Real-Time Automation
Unblocking The Main Thread Solving ANRs and Frozen Frames
Unblocking The Main Thread Solving ANRs and Frozen Frames
Top 5 Benefits OF Using Muvi Live Paywall For Live Streams
Top 5 Benefits OF Using Muvi Live Paywall For Live Streams
Data Cloud, More than a CDP by Matt Robison
Data Cloud, More than a CDP by Matt Robison
IAC 2024 - IA Fast Track to Search Focused AI Solutions
IAC 2024 - IA Fast Track to Search Focused AI Solutions
🐬 The future of MySQL is Postgres 🐘
🐬 The future of MySQL is Postgres 🐘
How to convert PDF to text with Nanonets
How to convert PDF to text with Nanonets
The Codex of Business Writing Software for Real-World Solutions 2.pptx
The Codex of Business Writing Software for Real-World Solutions 2.pptx
[2024]Digital Global Overview Report 2024 Meltwater.pdf
[2024]Digital Global Overview Report 2024 Meltwater.pdf
04-2024-HHUG-Sales-and-Marketing-Alignment.pptx
04-2024-HHUG-Sales-and-Marketing-Alignment.pptx
Presentation on how to chat with PDF using ChatGPT code interpreter
Presentation on how to chat with PDF using ChatGPT code interpreter
Raspberry Pi 5: Challenges and Solutions in Bringing up an OpenGL/Vulkan Driv...
Raspberry Pi 5: Challenges and Solutions in Bringing up an OpenGL/Vulkan Driv...
Software Engineering - Ch7
1.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 1 Requirements Engineering Processes
2.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 2 Objectives ● To describe the principal requirements engineering activities and their relationships ● To introduce techniques for requirements elicitation and analysis ● To describe requirements validation and the role of requirements reviews ● To discuss the role of requirements management in support of other requirements engineering processes
3.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 3 Topics covered ● Feasibility studies ● Requirements elicitation and analysis ● Requirements validation ● Requirements management
4.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 4 Requirements engineering processes ● The processes used for RE vary widely depending on the application domain, the people involved and the organisation developing the requirements. ● However, there are a number of generic activities common to all processes • Requirements elicitation; • Requirements analysis; • Requirements validation; • Requirements management.
5.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 5 The requirements engineering process
6.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 6 Requirements engineering
7.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 7 Feasibility studies ● A feasibility study decides whether or not the proposed system is worthwhile. ● A short focused study that checks • If the system contributes to organisational objectives; • If the system can be engineered using current technology and within budget; • If the system can be integrated with other systems that are used.
8.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 8 Feasibility study implementation ● Based on information assessment (what is required), information collection and report writing. ● Questions for people in the organisation • What if the system wasn’t implemented? • What are current process problems? • How will the proposed system help? • What will be the integration problems? • Is new technology needed? What skills? • What facilities must be supported by the proposed system?
9.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 9 Elicitation and analysis ● Sometimes called requirements elicitation or requirements discovery. ● Involves technical staff working with customers to find out about the application domain, the services that the system should provide and the system’s operational constraints. ● May involve end-users, managers, engineers involved in maintenance, domain experts, trade unions, etc. These are called stakeholders.
10.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 10 Problems of requirements analysis ● Stakeholders don’t know what they really want. ● Stakeholders express requirements in their own terms. ● Different stakeholders may have conflicting requirements. ● Organisational and political factors may influence the system requirements. ● The requirements change during the analysis process. New stakeholders may emerge and the business environment change.
11.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 11 The requirements spiral
12.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 12 Process activities ● Requirements discovery • Interacting with stakeholders to discover their requirements. Domain requirements are also discovered at this stage. ● Requirements classification and organisation • Groups related requirements and organises them into coherent clusters. ● Prioritisation and negotiation • Prioritising requirements and resolving requirements conflicts. ● Requirements documentation • Requirements are documented and input into the next round of the spiral.
13.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 13 Requirements discovery ● The process of gathering information about the proposed and existing systems and distilling the user and system requirements from this information. ● Sources of information include documentation, system stakeholders and the specifications of similar systems.
14.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 14 ATM stakeholders ● Bank customers ● Representatives of other banks ● Bank managers ● Counter staff ● Database administrators ● Security managers ● Marketing department ● Hardware and software maintenance engineers ● Banking regulators
15.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 15 Viewpoints ● Viewpoints are a way of structuring the requirements to represent the perspectives of different stakeholders. Stakeholders may be classified under different viewpoints. ● This multi-perspective analysis is important as there is no single correct way to analyse system requirements.
16.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 16 Types of viewpoint ● Interactor viewpoints • People or other systems that interact directly with the system. In an ATM, the customer’s and the account database are interactor VPs. ● Indirect viewpoints • Stakeholders who do not use the system themselves but who influence the requirements. In an ATM, management and security staff are indirect viewpoints. ● Domain viewpoints • Domain characteristics and constraints that influence the requirements. In an ATM, an example would be standards for inter-bank communications.
17.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 17 Viewpoint identification ● Identify viewpoints using • Providers and receivers of system services; • Systems that interact directly with the system being specified; • Regulations and standards; • Sources of business and non-functional requirements. • Engineers who have to develop and maintain the system; • Marketing and other business viewpoints.
18.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 18 LIBSYS viewpoint hierarchy
19.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 19 Interviewing ● In formal or informal interviewing, the RE team puts questions to stakeholders about the system that they use and the system to be developed. ● There are two types of interview • Closed interviews where a pre-defined set of questions are answered. • Open interviews where there is no pre-defined agenda and a range of issues are explored with stakeholders.
20.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 20 Interviews in practice ● Normally a mix of closed and open-ended interviewing. ● Interviews are good for getting an overall understanding of what stakeholders do and how they might interact with the system. ● Interviews are not good for understanding domain requirements • Requirements engineers cannot understand specific domain terminology; • Some domain knowledge is so familiar that people find it hard to articulate or think that it isn’t worth articulating.
21.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 21 Effective interviewers ● Interviewers should be open-minded, willing to listen to stakeholders and should not have pre-conceived ideas about the requirements. ● They should prompt the interviewee with a question or a proposal and should not simply expect them to respond to a question such as ‘what do you want’.
22.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 22 Scenarios ● Scenarios are real-life examples of how a system can be used. ● They should include • A description of the starting situation; • A description of the normal flow of events; • A description of what can go wrong; • Information about other concurrent activities; • A description of the state when the scenario finishes.
23.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 23 LIBSYS scenario (1) Initial assumption: The user has logged on to the LIBSYS system and has located the journal containing the copy of the article. Normal: The user selects the article to be copied. He or she is then prompted by the system to ei ther provide subscriber information for the journal or to indicate how they will pay for the article. Alternative payment methods are by credit card or by quoting an organisational account number. The user is then asked to fill in a copyright form that maintains details of the transaction and they then submit this to the LIBSYS system. The copyright form is c hecked and, if OK, the PDF version of the article is downloaded to the LIBSYS working area on the user’s computer and the user is informed that it is available. The user is asked to select a printer and a copy of the article is printed. If the article has been flagged as ‘print-only’ it is deleted from the user’s system once the user has confirmed that printing is complete.
24.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 24 LIBSYS scenario (2) What can go wrong: The user may fail to fill in the copyright form correctly. In this case, the form should be re-presented to the user for correction. If the resubmitted form is still incorrect then the user’s request for the article is rejected. The payment may be rejected by the system. The user’s request for the article is rejected. The article download may fail. Retry until successful or the user terminates the session. It may not be possible to print the article. If the article is not flagged as ‘print-only’ then it is held in the LIBSYS workspace. Otherwise, the article is deleted and the user’s account credited with the cost of the article. Other activities: Simultaneous downloads of other articles. System state on completion: User is logged on. The downloaded article has been deleted from LIBSYS workspace if it has been flagged as print-only.
25.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 25 Use cases ● Use-cases are a scenario based technique in the UML which identify the actors in an interaction and which describe the interaction itself. ● A set of use cases should describe all possible interactions with the system. ● Sequence diagrams may be used to add detail to use-cases by showing the sequence of event processing in the system.
26.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 26 Article printing use-case
27.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 27 LIBSYS use cases
28.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 28 Article printing
29.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 29 Print article sequence
30.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 30 Social and organisational factors ● Software systems are used in a social and organisational context. This can influence or even dominate the system requirements. ● Social and organisational factors are not a single viewpoint but are influences on all viewpoints. ● Good analysts must be sensitive to these factors but currently no systematic way to tackle their analysis.
31.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 31 Ethnography ● A social scientists spends a considerable time observing and analysing how people actually work. ● People do not have to explain or articulate their work. ● Social and organisational factors of importance may be observed. ● Ethnographic studies have shown that work is usually richer and more complex than suggested by simple system models.
32.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 32 Focused ethnography ● Developed in a project studying the air traffic control process ● Combines ethnography with prototyping ● Prototype development results in unanswered questions which focus the ethnographic analysis. ● The problem with ethnography is that it studies existing practices which may have some historical basis which is no longer relevant.
33.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 33 Ethnography and prototyping
34.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 34 Scope of ethnography ● Requirements that are derived from the way that people actually work rather than the way I which process definitions suggest that they ought to work. ● Requirements that are derived from cooperation and awareness of other people’s activities.
35.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 35 Requirements validation ● Concerned with demonstrating that the requirements define the system that the customer really wants. ● Requirements error costs are high so validation is very important • Fixing a requirements error after delivery may cost up to 100 times the cost of fixing an implementation error.
36.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 36 Requirements checking ● Validity. Does the system provide the functions which best support the customer’s needs? ● Consistency. Are there any requirements conflicts? ● Completeness. Are all functions required by the customer included? ● Realism. Can the requirements be implemented given available budget and technology ● Verifiability. Can the requirements be checked?
37.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 37 Requirements validation techniques ● Requirements reviews • Systematic manual analysis of the requirements. ● Prototyping • Using an executable model of the system to check requirements. Covered in Chapter 17. ● Test-case generation • Developing tests for requirements to check testability.
38.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 38 Requirements reviews ● Regular reviews should be held while the requirements definition is being formulated. ● Both client and contractor staff should be involved in reviews. ● Reviews may be formal (with completed documents) or informal. Good communications between developers, customers and users can resolve problems at an early stage.
39.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 39 Review checks ● Verifiability. Is the requirement realistically testable? ● Comprehensibility. Is the requirement properly understood? ● Traceability. Is the origin of the requirement clearly stated? ● Adaptability. Can the requirement be changed without a large impact on other requirements?
40.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 40 Requirements management ● Requirements management is the process of managing changing requirements during the requirements engineering process and system development. ● Requirements are inevitably incomplete and inconsistent • New requirements emerge during the process as business needs change and a better understanding of the system is developed; • Different viewpoints have different requirements and these are often contradictory.
41.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 41 Requirements change ● The priority of requirements from different viewpoints changes during the development process. ● System customers may specify requirements from a business perspective that conflict with end-user requirements. ● The business and technical environment of the system changes during its development.
42.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 42 Requirements evolution
43.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 43 Enduring and volatile requirements ● Enduring requirements. Stable requirements derived from the core activity of the customer organisation. E.g. a hospital will always have doctors, nurses, etc. May be derived from domain models ● Volatile requirements. Requirements which change during development or when the system is in use. In a hospital, requirements derived from health-care policy
44.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 44 Requirements classification Requirement Type Description Mutable requirements Requirements that change because of changes to the environment in which the organisation is operating. For example, in hospital systems, the funding of patient care may change and thus require different treatment information to be collected. Emergent requirements Requirements that emerge as the customer's understanding of the system develops during the system development. The design process may reveal new emergent requirements. Consequential requirements Requirements that result from the introduction of the computer system. Introducing the computer system may change the organisations processes and open up new ways of working which generate new system requirements Compatibility requirements Requirements that depend on the particular systems or business processes within an organisation. As these change, the compatibility requirements on the commissioned or delivered system may also have to evolve.
45.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 45 Requirements management planning ● During the requirements engineering process, you have to plan: • Requirements identification • How requirements are individually identified; • A change management process • The process followed when analysing a requirements change; • Traceability policies • The amount of information about requirements relationships that is maintained; • CASE tool support • The tool support required to help manage requirements change;
46.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 46 Traceability ● Traceability is concerned with the relationships between requirements, their sources and the system design ● Source traceability • Links from requirements to stakeholders who proposed these requirements; ● Requirements traceability • Links between dependent requirements; ● Design traceability • Links from the requirements to the design;
47.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 47 A traceability matrix Req. id 1.1 1.2 1.3 2.1 2.2 2.3 3.1 3.2 1.1 D R 1.2 D D D 1.3 R R 2.1 R D D 2.2 D 2.3 R D 3.1 R 3.2 R
48.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 48 CASE tool support ● Requirements storage • Requirements should be managed in a secure, managed data store. ● Change management • The process of change management is a workflow process whose stages can be defined and information flow between these stages partially automated. ● Traceability management • Automated retrieval of the links between requirements.
49.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 49 Requirements change management ● Should apply to all proposed changes to the requirements. ● Principal stages • Problem analysis. Discuss requirements problem and propose change; • Change analysis and costing. Assess effects of change on other requirements; • Change implementation. Modify requirements document and other documents to reflect change.
50.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 50 Change management
51.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 51 Key points ● The requirements engineering process includes a feasibility study, requirements elicitation and analysis, requirements specification and requirements management. ● Requirements elicitation and analysis is iterative involving domain understanding, requirements collection, classification, structuring, prioritisation and validation. ● Systems have multiple stakeholders with different requirements.
52.
©Ian Sommerville 2004
Software Engineering, 7th edition. Chapter 7 Slide 52 Key points ● Social and organisation factors influence system requirements. ● Requirements validation is concerned with checks for validity, consistency, completeness, realism and verifiability. ● Business changes inevitably lead to changing requirements. ● Requirements management includes planning and change management.
Jetzt herunterladen