1pbi_sas_08_exec_shullseptember 2008mac-t ivv-08-153 dr. forrest shull, fcmd kurt woodham, l-3...

1PBI_SAS_08_Exec_Shull September 2008MAC-T IVV-08-153

Dr. Forrest Shull, FCMDKurt Woodham, L-3 Communications

OSMA SAS 08

Infusion of Perspective-Based Inspections for

NASA IV&V

(Executive Briefing)


A procedural technique incorporating three best practices: Giving each reviewer a particular and unique focus (or perspective)

on the document under review Base perspectives on document stakeholders to help understand

necessary participants, relate inspection tasks to development skills

Making individual review of a document an active (rather than passive) undertaking

Articulating the quality aspects of interest

Uses defect analysis (e.g. from bug trackers, configuration management systems, previous inspection, or test results) as one input on which to customize a solution

Perspective-Based Inspection (PBI)


History 2001-2003: SARP research funding

Refined basic approach, implemented on NASA projects and in classrooms, measured results

2004: Tech infusion with Flight Software Branch / GSFC Goal: Produce new Branch standards Success metric: Based on experiences on pilot(s), how much of the recommended

process is adopted by Branch?

2004: Tech infusion with United Space Alliance / JSC Goal: Reduce defect slippage over current increment Success metric: Show reduced defect slippage on PB-inspected artifacts

2007-2009: SARP funding for improved general inspection planning

Other Results and Benefits Improved defect detection effectiveness substantially (NASA & elsewhere) Helped re-invigorate inspection practices Forms the basis of industrial and academic training

Perspective-Based Inspection (PBI)


Tailoring required for new domain, new issues, new artifacts

Adopting PBI for IV&V

Requirements

Specifications

PB Inspection

System reference model

Fanny May : Loan Arranger

Borrower : Borrower

A Lender : Specified Lender

Loan : Loan

verify_report()

new_loan(lender, borrowers)

new_

look_for_a_lender(lender)

look_for_a_loan(loan)

look_for_a_

update_loan(lender, borrower)

update_

lender :

new_lender(name,contact, phone_number)

update(lender)

monthly_report(lender, loans, borrowers)

identify_report_format()

Receive Monthly Report


Borrower : Borrower


Loan : Loan

verify_report()


new_



look_for_a_


update_

lender :


update(lender)





Borrower : Borrower


Loan : Loan

verify_report()


new_



look_for_a_


update_

lender :


update(lender)




PB Inspection

Requirements defects

Model defects


Adopting PBI for IV&V: Tailoring Process Understand team-specific quality concerns Understand likely perspectives for the team Refine set of perspectives and define

procedures for each. E.g., What quality concerns map to which

perspectives What is a feasible/effective process for checking

those concerns

Finalize procedures and provide training Analyze ongoing inspection results (and

update procedures if necessary) Monitor downstream defect profile Write final report

Status: Reviewed sample models & processes;

Constructed draft PBI techniques;

Created draft training course


Initial perspectives for this domain: Modeler

Uses requirements & existing models to create the next iteration Quality foci: Appropriate level of detail in requirements; completeness

and clarity of requirements & models; consistency and correctness of models

Domain expert Assesses whether model accurately and usefully captures domain Quality foci: Correctness of requirements (independent of models);

identification of stakeholders and evaluation of usability from their POV; checking flow of control & use of reusable components

Quality assurance Assesses whether models and system can be validated properly Quality foci: Handling of exception cases / unexpected system conditions;

robustness of system; testability

Adopting PBI for IV&V


Validate & refine PBI instantiation via interviews Check perspectives and associated scenarios with key stakeholders Flesh out detailed approaches for each perspective with respect to

each defect category

Application In context of IV&V of JWST Training course material delivered and training will be executed near-

term Technology provider will facilitate initial inspections, and will be on-

call during subsequent inspections

Evaluation Success metric: Effectiveness of PB inspection in comparison to past

inspections

Path Forward


Forrest Shull

[email protected]

301-403-8970

Contact information

Kurt Woodham

[email protected]

757-644-5807

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