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Traceability

Traceability. Systems Engineering STD. Requirements Management2 Traceability. Contents. Terminologies Techniques A model of traceability Tools : case study (RTM, Slate, DOORS : what will be available at HPI !!). What specific to Traceability in Req. Management ?.

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Traceability

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  1. Traceability Systems Engineering STD Requirements Management2 Traceability

  2. Contents • Terminologies • Techniques • A model of traceability • Tools : case study (RTM, Slate, DOORS : what will be available at HPI !!)

  3. What specific to Traceability in Req. Management ? • Traceability increase software quality throughout the life of the project • Most important issue in RM • Many facets of Soft.Eng. Can be improved through RT • Standard 2167A (US DoD)

  4. A recent event : Mad cow and Hamburger !! ?

  5. Terminologies • Part of requirement management process • Technique to provide relationship between requirement design and final implementation • How and why system development products satisfy stakeholders requirements • Ability to discover the history of every feature of a system • A quality factor • Many standards (2167-A then 498) require the development of traceability documents

  6. Techniques • Objectif : get all links during lifecycle of requirement • Link to stakeholders • Associated design • Associated implementation • Validation procedure • Concept of operation • Etc ...

  7. Techniques • Cross reference schemes • Keyphrase dependancy • Templates • Matrices • Matrix sequence • Hypertext • Integration documents All differs in the intent of information traced and objective of tracing

  8. Essence of traceability • Of What (information) • In what way (information prsentation) • For whom • Example : Who coded the program • Who : we need the programmer • What way : name, the company, the team ? • For whom : to whom this information is addressed (not anybody can have any information : information abstraction and ... Security)

  9. Traceability Matrix • Used to relate requirements to others software developments artifacts The relation can be allocatted a type Design Di S/w modules Req R1 R2 X Rn N/A X : relational link between a requirement and a design N/A : Non applicable (no apparent link)

  10. Cross references and index schemes • References made across several items (design, modules, requirements,..) in order to link two items or artifacts. • Example : There should be a high-level of traceability between "Logical Architecture" and "Physical Architecture" • The logical and physical architecture are tied together with a collection of cross-reference tables in the "Traceability Matrix"

  11. Tracing languages • Database query languages Used in existing powerfull RT tools (RTM use runtime version of Oracle) • Regular expressions Used in formal TOOR approach TOOR • is designed for tracing requirements in system development. • It considers as objects, in the computing science sense of the word, any artifacts used during the development of a software system, e.g., an interview transcript, a video tape, a design chart, a program specification text, a system manual, etc. • It also considers the possible relations between any two objects as an object itself

  12. Tracing Process and models • Trace definition : precise semantic (formalising links between objects) • Trace production : results of action (ideally : automated tracing production) • Trace model : link between classes dont give exact purpose of the link • Trace extraction : What are the requirement that are linked to a specific software; or what are the software modules linked to a specific requirement • Traceability support : A huge amount of information to manage

  13. TOOR . A formal approach • Developped at Oxford (Goguen, Pinheiro) • Object based (see RTM tool too) • Declaration using FOOP (based on OBJ) • Traceability links between any artifacts created by different documents • Graphical interface • Tracing are forward and backward

  14. TOOLS : RTM • Requirements Traceability Module (Chipware) • Other tools : DOORS (telelogic), Slate (QSS) • Essential approach • A generic meta model • All links are specified in the relation between between classes • Document generation • Can be customised to any meta-model defined by user

  15. A model of traceability

  16. A model of traceability Separation between source and other objects • A manager • A user • A programmer • -Email • Doc • phone call • Meeting minutes • A Requirement • A Designed architecture • A software module

  17. A model of traceability

  18. Dependancy links issues • Existence of a link and its meaning • Stakeholders dependencies • Requirements dependancies : a requirement is based on the assumption on satisfaction of another requirements : the software can be coded in C only if here is available compiler on operating systems imposed in another requirement • Task dependencies • Resource dependancies • Temporal dependancies (temporal order)

  19. Relative importance of dependancy links • Attribution of weight on on link • Qualitative • Quantitative • Example : The voltage change in one component affect another component • Links can be many levels of abstraction • Requirement and derived rtequirement • Requirement and stackholder • Not injective or surjective relation

  20. Conclusions • A model of traceability should be defined • A need for a tool • Two way to implement the tool • Specific tool for RT • A database system as Oracle.

  21. Conclusions and recommendations • State of the art and limitations • All approaches require a great deal of manual effort to define the links • All rely on purely syntactic information with no semantic or context • capture situations where many people participate • Capture changing patterns of participants

  22. Conclusions and recommendations • Informational problem • Tracking useful information • Inadequate prerequirement traceability • Informal communication • People attach great importance to personal contact and informal communication • These always supplement what is recorded in database • Traceability links database tells only a part of the story • Finding the appropriate people

  23. Conclusions and recommendations • Involvement Who has been involved in the production of a requirement and how • Responsibility • Who is responsible for a specific requirement • Who is currently responsible • Context in defining change of responsibility • Change • At what point in the life of a requirement a need for a change is possible • Who needs to be informed by a change

  24. Conclusions and recommendations • Loss of a knowledge  What are the items regarding the loss of a project knowledge due to turnover over concerned personnel • Others • Verification and validation • Maintenance • Coverage (types of links)

  25. Next lecture Requirements management Traceability Validation and Verification

  26. Paper Reading and assignments • Paper reading Mandatory : Traceability : IEEE Trans jan 2001 by Jark & Ramesh • Other : see list paper reading assignment

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