from requirements management to requirements authoring - innovate 2014
DESCRIPTION
The presentation suggests an improved way to produce high quality requirements at authoring stage, where the quality of the specification is calculated on the fly, while the analyst writes the requirements. The correctness of a single requirement, as well as the consistency and completeness of the specification is calculated and managed.TRANSCRIPT
From Requirements Management to Requirements Authoring – An Experience Report from Airbus Group
Jean-Claude Roussel, Gerard Auvray - Airbus Group
Juan Llorens – The REUSE Company
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50%50%
29%29%
21%21%
30%30%
52%52%
18%18%
20%20%
22%22%
58%58%
Requirements Engineering Capability
Pro
ject
Pe
rfo
rman
ces
Correlation between Project Performances and Requirement Engineering Capability
Why doing Requirements Engineering ?
Source : Report on SE Effectiveness Survey NDIA-IEEE-SEI/CMU-INCOSE Nov 2012
• 70% of defects are introduced during requirements phases– It is important to write effective Requirements
• Experiences shown that about 25% of system Requirements are critical and can grammatically be improved
– No Shall: 8 to 10%
– Forbidden words: 10 to 15%
– Subject, multiple objects, design: 15%– Incorrect grammar: 50%, …
• Requirements error costs are high– Fixing requirements after delivery may cost up to 100 times the one for fixing a requirement error
• Training, best practices and verifying requirements by reviews can help to get complete and consistent requirements:
– But the process is costly and time consuming
• Reduce the number of iterations between System Engineers and sub-contractors and improve the verification activities
Why doing Requirements Engineering ?
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(source: INCOSE Systems Engineering Handbook )
Why doing Requirements Engineering ?
Survey on Industrial Practices: Most common defects on Requirements
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Study in the scope of RAMP project (Requirements Analysis and Modeling Process) in partnership with Airbus Group, RENAULT, EDF, ADN, CORTIM, ENSTA, IRIT, PARIS 1 UNIVERSITY (end 2010 over 22 industrials in several domains worldwide: interviews and questionnaires)
10/04/23
Requirements are mainly written in natural language
QUALITYISSUES !
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A perfect…bad requirement !
Whatever the context, the system should be able to switch-off as quickly as possible, to restart without inducing any perturbation and at the same time to inform the operator in a friendly and understandable manner…
Need to perform a Requirement Quality Analysis against all the set of the system Requirements to improve the requirement quality before any delivery.
Requirement not SMART (Specific, Measurable, Attainable, Realisable, Traceable)
Ambiguous (What System ?)Several muddled requirements (switch-off, restart, inform)No use of shallNot measurable (quickly, same time,,..)Not testable (friendly, understandable,..)…
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From Requirements Management to Requirements Authoring
Requirements Quality Control:Huge review effort for quality verification
My tailor is rich
I should need RAT
Requirements Writing:Working with requirements inside DOORS
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Requirements Quality Control:Huge review effort for quality verification
Requirements Quality Assurance:Authoring “right the first time” on top of DOORS
My tailor is rich
I should need RAT
Requirements Writing:Working with requirements inside DOORS
Requirements Quality Control:Smaller review effort for quality verification
From Requirements Management to Requirements Authoring
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A first answer : Requirements Quality Analysis (RQA) Tool
– Tool delivered by TRC (The Reuse Company)– Completely linked with DOORS Tool
– Focusing on Syntactic analysis (DQA) and Semantic analysis (RQA V4.1)
– Tool evaluation– Airbus Group Innovations
– Airbus Defense and Space
– Close cooperation with TRC in order to improve the tool
– Tool deployment– Limited in Airbus Defense and Space
– R&T project focusing on how to improve the requirements quality analysis process
– Operationally deployed in Airbus (Commercial Aircraft)• A320neo Cabin Flex
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From Requirements Analysis to Authoring
So far RQA V3 was a verification tool:– Checking the quality of individual requirements once they are written
– Based on +25 metrics
– Checking the consistency of the overall specification
RQA has evolved towards the Requirements Quality Suite (RQS) in V4– Supports the CCC approach (Correctness, Consistency and Completeness)
– V4 is mainly focused on “authoring”
– Includes RQA, Requirements Authoring Tool (RAT) and KM
RAT: “The SMARTer* way to create requirements”:An assistant to Engineers during the authoring processIncluding a wide set of customizable boilerplatesHelping Engineers during authoring with an intellisense system * SMART stands for Specific, Measurable, Attainable, Realisable,
Traceable
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Requirements Quality Analysis : Product Improvement
DQAV2.1
RQAV3.1
RQSV4 – V14S
em
an
tic
s
Syntactic +
Semantic
Syntactic Check
Authoring
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The Requirements Quality Suite (RQS)
The Requirements Quality Suite (RQS) intends to tackle requirements quality management by offering a set of tools and processes.RQS models requirements quality using the CCC approach (Correctness, Consistency and Completeness)
Requirements Quality Analyzer (RQA): to setup, check and manage the quality of a requirements specification.
Requirements Authoring Tool (RAT): to assist authors in the process of creating requirements with the right level of quality
knowledgeMANAGER (kM): to manage knowledge around a requirements specification: -the ontology it is based on-the structure of the requirements to be used in the project-the communication between authors and domain architects.
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Requirements Quality Metrics : CCC Support
Consistency(semantic)
Consistency(inconsistent
units)
Completeness(missing req.)
Correctness(individualmetrics)
Completeness(missing links)
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Correctness : Individual requirement supported metrics
– Size
– Readability
– Conditional vs. imperative
sentences
– Active vs. passive voice
– Optional sentences
– Ambiguous sentences
– Subjective sentences
– Implicit sentences
– Abuse of connectors
– Negations
– Speculative sentences
– Use of false friends
– Design terms
– Flow terms
– Number of domain nouns and
verbs
– Acronyms
– Hierarchical levels
– Volatility
– Number of dependences
– Forbidden Words
– Standard Requirement (match
pattern)
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Consistency : Supported Metrics
Consistency applies to requirements sets
–Redundant requirements: Several requirements expressing the same
need at the same level of abstraction.
–Inconsistent units: Different requirements in the same
module/block/project uses different metric units.
–Inconsistent Content: Different requirements present value restrictions
that are not compatible.
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Completeness: Supported Metrics
Completeness applies to requirements sets
–Missing requirements: Lacks the existence of requirements expressing
the same need at the different level of abstraction in different modules/blocks
of the same project.
–Missing Links Lacks the existence of links between requirements
expressing the same need at the different level of abstraction in different
modules/blocks of the same project.
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RAT : Requirements Authoring Tool
• Main features:– Assisting authors while they’re writing requirements– Following a agreed upon set of patterns
• Other (on the fly) features:– Quality assessment (correctness based
on individual metrics) on the fly– Consistency analysis on the fly– Missing links on the fly– Inconsistent units analysis on the fly
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• Author assistance on the fly (typing requirement)
Pattern choicePattern choice
Valid paths to fulfill the selected patterns
Ontology terms to keep fulfilling the selected patterns
RAT : Requirements Authoring Tool
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• Author assistance on the fly (done requirement)
Pattern fulfilledPattern fulfilled
RAT : Requirements Authoring Tool
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• Quality assessment on the fly
RAT : Requirements Authoring Tool
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• Semantically similar requirements on the fly
There’s a requirement in the SKB very similar to the writing requirement
There’s a requirement in the SKB very similar to the writing requirement
RAT : Requirements Authoring Tool
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• Inconsistent measurement units on the fly
There’s a requirement in the SKB conflicting with the writing requirement
There’s a requirement in the SKB conflicting with the writing requirement
RAT : Requirements Authoring Tool
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Knowledge Manager
• Main features:– Vocabulary management– Thesaurus management– Requirements Patterns management– Semantic indexing and retrieval services
• Ontology construction:– By reusing existing vocabulary, thesauri, ontologies– By creating a semantic graph out of existing
documentation – By “elicitating” with the help of experts– By attending the suggestions provided by end users
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The System Knowledge Base: An ontology
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Controlled vocabulary: valid terms, forbidden terms… Optionally can include a Glossary (description for every term)
Taxonomy: terms hierarchically organized
Thesaurus: hierarchies, associations, synonyms…
Light Ontology: syntactic and Semantic groupings for Terms and Actions (verbs). Domain terms and verbs
Full-Ontology: patterns and requirements structures
Pattern Management
Full-Ontology: boilerplates and requirements structures
Knowledge (Ontology)Management
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Knowledge Manager
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