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Analysis I

This analysis focuses on identifying and organizing the parts of a system, analyzing how it is stored and organized, and ensuring traceability and verification. It includes formal and informal techniques such as inspections and prototypes, aiming to validate the system and meet user/stakeholder expectations.

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Analysis I

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  1. Analysis I

  2. Analysis • Identify the parts • How is it organized? • How is it stored? • traceability • Verification • formal • reuse domains • inspections

  3. Analysis • Validation • Close to the users/stakeholders • informal • prototyping (mock up, storyboard)

  4. Analysis do Carry out use Carry out Validation use use Identify the parts People Verification dependes on Tools Methods Points of View

  5. Verification Are we building the thing right? (compared to other products) among models Validation Are we building the right thing? (regarding stakeholders/users desire) Between the UofD and a Model Verification vs Validation

  6. Analysis Loop UofD Facts gathering communication * model ** yes problems? problems communication No * modeling ** identifying the parts model

  7. Identification of the parts • Depends on the models are organized and stored • Linked to modelling and elicitation • 90% of the problems in 10% do system

  8. REQUIREMENTS UofD a e c j g b d f i h problem Req. document Version 1 Requirements Documentation definition Req. document Version 2 Req. document Version 3 design software implementation maintenance

  9. Validation • Are we building the right product? • We have to compare the UofD with users/stakeholders expectations • Run Scenarios (Reading them in meetings) • Prototype

  10. Validation Strategies • Informal corroboration • storyboards • prototypes

  11. representation info Facts gathering facts methods analyze problems More Information Needed communicate Delta

  12. Identifying Deltas • Informal corroboration  = list of problems (information, facts) • Using prototypes  = facts behavior (users expectations, facts) • Using viewpoints  = inconsistencies (Factsa, Factsb) wrong facts(Factsa, Factsb) missing facts (Factsa, Factsb)

  13. Validating through scenarios use • As many times as possible • The earliest the better • If possible validate the candidate scenarios list • Scenario Validation goal: elaborate the DEO list( Discrepancies, errors and omissions) • Users’ commitiment is essential

  14. Main stream • Validate scenarios with users using structured interviews • Strategies: • Read scenarios aloud together with users • Ask Why

  15. Validation Through Scenarios • Gradual confirmation of scenarios parts (objective, actors, resources) • Feedback for LEL • Tag scenarios where doubts arise • Make notes of discrepancies, errors or omissions

  16. Storyboard [Leffingwell & Widrig] • Elicit reaction such as “Yes, but…” • Passive, Active or iterative • Identify actors, explain what happens to them and describe how it happens • More effective to projects with innovative or unknown content

  17. Storyboard • Pros: • cheap • User friendly, informal and iterative • Allow to criticize system interface early in the project • Easy to create and modify

  18. Types of storyboard • Passive • Static screens • Business rules • Reports • Active • Presentation (As in PowerPoint) • animation • simulation • Iterative • demo ( free browsing) • Iterative presentation

  19. Storyboard passive active iterative presentation screen prototype animation demo Business Rules simulation Iterative Presentation reports Complexity and cost

  20. Prototype • Prototypes are partial implementation to help stakeholders, users and developers to better understand system requirements

  21. Prototypes • Also helps to elicit reactions such as “ Yes, but…” • Help to clarify fuzzy requirements • Requirements that are known but not well defined or not well understood • Help elicit reactions such as “Now that I can see it working it comes to me that I also need…..” • Availability of tools that help to build fast and cheap prototypes

  22. Types of Prototypes [Davis] • Throw away • It has to work • Use any means to implement the desired result (it does not care for quality code) • Once the requirements are elicited the prototype is deleted • Evolving • Implemented using the same architecture being used in the system • The system may be an evolution of this prototype

  23. Prototype Vertical X Horizontal • Horizontal • Implements a large portion of the functionality • Vertical • Implement a few functions • Better quality

  24. Verification • Are we building the product correctly ? • Use of Models • representations/languages • Use of formalisms • Informal Techniques

  25. Use of formalisms • Formal Proofing of a model • Theorem proofing • Detection of discrepancies between the model and the meta models • Model Proofing

  26. Informal Techniques • Walk through • Inspections

  27. Walk through • ad hoc preparation • Meeting (author(s), evaluator(s), secretary) • Reading • author reads • Evaluators hear • Evaluators point out problems (questions) • Secretaries write down problems • List of problems

  28. ... Isnpection Meeting Preparation List of problems Processes For Meetings Reading Inspection Protocol Inspections

  29. Inspections • Process • planning • Global Vision • preparation • inspection (meeting) • re-work (corrections) • Follow-up

  30. Inspections • Roles • moderator • author • codifier (secretary) • inspector

  31. Checklist • Points to be checked/observed during the inspection process • Depends on the type of material to be inspected (DFD, scenarios, use cases …) • Depends on the focus for the inspection

  32. DFD • Checklist DFD • The documentation should contain: • Date, numbered pages, list of topics, change and version control • Process represented by a numbered circle • Identifier should begin with a verb • Maximum number of processes should be 7 +- 2

  33. OO • Checklist OO: • Are all classes represented using rectangles with 1, 2 or 3 compartments? • Are there two classes with the same name? • Are there classes without defined relationships? • Are the attributes and methods for each class adequate?

  34. N-Fold Inspection • Many teams • Each one carries out an independent inspection process • Compare results • Final Report

  35. User Moderator Leaders Team 3 Team 2 Team 1 Each document is revised by n teams where each team uses the inspection process to find errors Figura N-fold

  36. Parallel is better • Multiple inspection teams find more defects than one single bigger team • The teams tend to find sub sets of different defects • The combination of the various results from the different teams tends to sum not to be redundant

  37. Example – ?? HP ?? • Roles: • inspectors: • Items – errors, omissions, inconsistencies, confusion • Related subjects: items that go beyond the scope of the inspection • Owner of the document • Identify (agrees) • Correct the errors • secretary • Annotate items and subjects • Before and during the meeting

  38. Example - HP • Main Moderator • Owner of the inspection process • Collects and communicate statistics • Points to correction in the inspection process • Focal point for changes on inspection standards and checklist • moderator • Manages the process • Facilitates inspection • Statistics • Send status and subjects to management

  39. HP - Process • Planning • plan inspection • moderator and owner • kick off • Quickly update the team about the document and the inspection process • All member involved

  40. HP - Process • Preparation • Identify items and subjects • All members participate • Meeting • Identify items and subjects • Report items and subjects • All members participate • Cause/Prevention • brainstorm causes • recommend solutions • All members participate

  41. HP - Process • Re-work • Verify and point errors or defects • Owner and moderator • Follow up • Release the document • Owner and moderator Key lessons in achieving widespread inspection use - Grady & Slack - IEEE Software, July1994, pp.46-57

  42. Challenges from inspections • Big Requirements Document • Informal and incremental revisions during the development of specification • Each inspector starts from a different point • Divide into many small teams – each inspects a specific part of the document

  43. Challenges from inspections • Large inspection teams • Difficult to schedule meetings • Parallel conversation • Difficult to get an agreement • What to do? • Be sure the participants are thee to inspect and not to “spy” the specification or to keep a political status

  44. Challenges from inspections • Large inspection teams • Understand which point of view (client, user, developer) the inspector is using and keep only one to each interested part • Establish many small teams and carry out the inspection in parallel. Combine the lists and remove redundancies.

  45. Challenges from inspections • Geographical distance between inspectors • videoconference, teleconference, e-mail, web • Difficult to observe corporal language and expressions, • Difficult to moderate • 25% reduction on the effectiveness • [Wiegers98] - The seven deadly sins of software reviews - Software Development -6(3) pp.44-47

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