quality re pres ebert rudorfer med conf2011 v4
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© 2011 Siemens Healthcare Diagnostics Inc. Page 1Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
© 2011 Siemens Healthcare Diagnostics Inc. All rights reserved.
Quality Requirements Engineering for Medical Systems
MedConf 2011 Munich, 05. October 2011
© 2011 Siemens Healthcare Diagnostics Inc. Page 2Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Contents
Goals
Brief Look on Siemens and Vector
Business and Environment
Quality Requirements Engineering
Results and Summary
Further Information
© 2011 Siemens Healthcare Diagnostics Inc. Page 3Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Goals
Provide an overview on quality requirements engineering challenges in a medical device project
Apply quality requirements engineering for a critical system
Share experiences how quality requirements can be successfully addressed
Show lessons learned and achieved benefits
© 2011 Siemens Healthcare Diagnostics Inc. Page 4Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Contents
Goals
Brief Look on Siemens and Vector
Business and Environment
Quality Requirements Engineering
Results and Summary
Further Information
© 2011 Siemens Healthcare Diagnostics Inc. Page 5Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Siemens Healthcare
Immunoassay Clinical ChemistryMolecular Hematology Lab AutomationUrinalysis Point of Care
In vitro diagnostics (laboratory systems)
X-Ray ComputedTomography
MagneticResonance
MolecularImaging
Ultrasound
In vivo diagnostics (imaging)
IT Solutions
Oncology
© 2011 Siemens Healthcare Diagnostics Inc. Page 6Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Vector Consulting ServicesYour Partner in Achieving Engineering Excellence
… offers a comprehensive consulting and training portfolio as well as process tools for optimizing product development
… serves industries such as automotive, aviation, IT and telecom, machinery and plants, medical, and railway
… is supporting clients on efficiency improvement, PLM/ALM, functional safety, CMMI/SPICE, requirements engineering and product management
… as a group serves companies across the world, with over 1000 employees and sales of well over 150 Mio € pa
www.vector.com/consulting Railway
IT & Telecom
Automotive
Aviation& Defense
Machinery& Plants
Medical
© 2011 Siemens Healthcare Diagnostics Inc. Page 7Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Contents
Goals
Brief Look on Siemens and Vector
Business and Environment
Quality Requirements Engineering
Results and Summary
Further Information
© 2011 Siemens Healthcare Diagnostics Inc. Page 8Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Business Challenges
Environment: Shorten time-to-market Cuts in healthcare budgets Continuous product innovation
© 2011 Siemens Healthcare Diagnostics Inc. Page 9Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Business Challenges
Product:Safety-critical: Critical for health and sustainability(e.g. bodily injuries, wrong treatment)Security-critical: Critical for preserving information integrity(e.g. access to sensitive data)Mission-critical: Critical for mission continuity(e.g. unavailability)Business-critical: Critical for business success(e.g. damage to image)
Critical need for quality requirements engineering
© 2011 Siemens Healthcare Diagnostics Inc. Page 10Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Contents
Goals
Brief Look on Siemens and Vector
Business and Environment
Quality Requirements Engineering
Results and Summary
Further Information
© 2011 Siemens Healthcare Diagnostics Inc. Page 11Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Quality Requirements Engineering (QRE):Overview
Quality Requirements (QR) A quality requirement describes a qualitative property that a system
or individual component of the system must exhibit. Sometimes called: non-functional requirements. They extend the functional requirements. Examples: Availability, maintainability, security, reliability.
Quality Requirements Engineering (QRE) The disciplined and systematic approach to elicit, specify, analyze,
prioritize, commit, verify, validate, assure and manage quality requirements throughout the life-cycle. Focus areas: Systems engineering, processes and product life-
cycle
© 2011 Siemens Healthcare Diagnostics Inc. Page 12Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
QRE: Focus on Systems engineering, processes and product life-cycle
Quality Requirements Engineering (QRE) needs to balance systems perspective and business needs.
SystemsEngineering
ProcessesProduct
Life-Cycle
© 2011 Siemens Healthcare Diagnostics Inc. Page 13Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Quality Requirements Engineering (QRE):Example: Security
System analysisSystem designVerification
Subsystem analysisSubsystem designVerification
SW AnalysisSW designVerification
Software- / Hardware Implementation and Verification
System testValidation
System integration
Subsystem testSubsystem integration
SW- / HW- testSW- / HW- integration
Security reviewPenetration tests
Risk assessmentArchitectures, components
Design for securityGuidelines, standards
Common criteria
Security requirementsEnvironmental analysis
Operational threatsMisuse Cases
Code analysisSecurity reviews
Security assessments
Incident / risk alertsFailure analysis
Patch management
Life-Cycle Perspective
Test scenariosSecurity archi-tecture design
Test driven development
Checklists
Life-Cycle
© 2011 Siemens Healthcare Diagnostics Inc. Page 14Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Quality Requirements Engineering (QRE):Example: Security
Security architecture and design Develop security architecture on system level Keep architecture as simple as possible Adaptation of existing building blocks is difficult
Implementation Create and use proven software components Use coding standards, guidelines Employ tools for static analysis, fix compiler warning causes
Consider quality requirements as a system property.Use different means to prevent critical defects.
SystemsEngineering
© 2011 Siemens Healthcare Diagnostics Inc. Page 15Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Quality Requirements Engineering (QRE):Example: Security
Security verification:Security reviews on all security-relevant artifactsTests and simulations
Security validation:Validation tests (completeness, correctness) – can be
handled in context of “normal” validationPenetration tests (vulnerabilities) – high manual effort,
requires specific expertise
Strive for detection of potential weaknesses and insufficient implementation at the earliest possible point of time.
SystemsEngineering
© 2011 Siemens Healthcare Diagnostics Inc. Page 16Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Quality Requirements Engineering (QRE):Example: Security
SecurityProtocolDesign
Specification
Test Cases
Simulation / Test
Test Results
Example: Simulation / test of a security protocolSystems
Engineering
© 2011 Siemens Healthcare Diagnostics Inc. Page 17Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Quality Requirements Engineering (QRE):Example: Security
Activity Benefit
Adapt mature development
processes to factor in
security engineering.
Security engineering activities are known,
scheduled, and executed within “normal” development.
Security is not treated as add-on.
Synergies can be exploited.
Elicit security requirements
in the beginning of the
project.
Assets to be protected are clearly identified.
Basis for realization of security.
Test cases for security validation can be deduced.
Review or test every security
relevant artifact, use analysis
and test tools.
Identification of issues at the earliest possible time.
Automated tools increase confidence and reduce effort.
Manage embedded security
competencies.
Specific embedded security expertise available when necessary.
Quality requirements engineering is deeply engrained in systematic requirements engineering
Processes
© 2011 Siemens Healthcare Diagnostics Inc. Page 18Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Project Overview
Large-Scale Medical Device Projects
Several thousand single product requirements
Several million lines of code
Several hundred developers in 5+ locations worldwide
Multi-fold clinical applications
© 2011 Siemens Healthcare Diagnostics Inc. Page 19Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Case Study: Embed Quality Requirements Engineering into an Existing RE process
Selected Issues
Difficult mapping of requirements to existing platform
• Identification of customer value
• Controlling architectural complexity
• NFRs difficult to define
Solutions
Feature model
Value-based ranking of QR
Architecture Model Mapping
Quality Tree
© 2011 Siemens Healthcare Diagnostics Inc. Page 20Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Issue 1: Mapping of requirements to Platform – Solution “Feature Model”
Highest Level
Hierarchical View
Graphical View
Benefits: Higher level abstraction of grouping of
requirements into sellable units: From 5,000
product requirements to 800+ features
(factor ~ 6)
Visual domain model for healthcare
workflows (tree & graphical)
Reduction of (de-) scoping effort by ~ 30% (*)
Reduction in time to understand aspects of
the system
Hierarchical relationships enable mapping of
stakeholder requests and visualize
dependencies
Basis for introducing variability management
Feeds the product backlog
(*) S
ourc
e:E
stim
ates
from
pro
duct
man
ager
s
© 2011 Siemens Healthcare Diagnostics Inc. Page 21Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Issue 2: Identification of customer value –Solution “Forced Ranking”
Characteristics:
Ranking is used to determine the release backlog Main criteria for ranking are business value,
technical risk and effort
Benefits:
Only features with the highest business value (and feasibility) are implemented Feature independence assures
parallelization of development Simulation of optimal release plan (what-
if analysis)
© 2011 Siemens Healthcare Diagnostics Inc. Page 22Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Issue 3: Controlling – Solution “Architecture Model Mapping”
Characteristics:
Identifies links between features and their
implementation
Explicit modeling of variability in the architecture
Benefits: Architectural decisions motivated by features
and product-line variability
Enable reduction of architectural complexity
Support impact analysis for (de-) scoping
sessions Early identification of architectural risks
Improved accuracy of early effort estimates
Reduction of number of scoping sessions
F
F F F
SWF SWF SWF SWF SWF SWF SWF
S
SS SS SS
C C C C C C
Feature Model
Architecture Model
© 2011 Siemens Healthcare Diagnostics Inc. Page 23Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Issue 4: NFRs difficult to define for platform – Solution “Quality Tree”
Characteristics: Quality requirements most challenging to
define (subjective, domain-specific)
Quality Tree provides an effective means for collecting and prioritizing qualities
Analysis technique based on business drivers, key usage scenarios and international standards
Benefits:
Identification of key architectural risks to consider Transparency of qualities‘ definition to all
stakeholders Explicit link of business drivers and
platform architecture
Example Quality Tree - Extract
Example: Learnability
Learning time of an educated physician shall be less than x minutes ...
© 2011 Siemens Healthcare Diagnostics Inc. Page 24Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Contents
Goals
Brief Look on Siemens and Vector
Business and Environment
Quality Requirements Engineering
Results and Summary
Further Information
© 2011 Siemens Healthcare Diagnostics Inc. Page 25Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Quality Requirements Engineering
Value orientation Global competition Cost pressure Shorter Life-Cycles Reliability Safety Resilience Serviceability Complexity Auditability
Impacts on RequirementsEngineering
1. Understand valuation of quality requirements
2. Consistently prioritize
3. Address system context
4. Stay agile and lean
5. Model quality requirements end-to-end
6. Systematically build quality
7. Manage knowledge
© 2011 Siemens Healthcare Diagnostics Inc. Page 26Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
ResultsQuality Requirements Engineering Pays Off
Improved system availability and reliability Ca. 30% Reduction of review
effort due to early feature reviews vis-a-vis quality requirements Ca. 25% reduction of upfront
requirement engineering work due to incremental requirements engineering Use of quality tree assures a clear
focus on future customer needs and elimination of unnecessary redesigns
© 2011 Siemens Healthcare Diagnostics Inc. Page 27Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Key Take-Aways
Successful development of critical systems requires a business-driven requirements engineering approach with specific consideration of quality requirements
A value-feature perspective for functional and quality requirements allows tracing business needs to implementation details
Introducing a platform concept means to restructure quality requirements and link them to architecture components
Continuous assessment and verification of business needs is necessary to judge priorities of quality requirements
Consequent quality requirements engineering needs profound organizational change management to facilitate cross-cutting perspectives, innovative methodologies and collaboration
© 2011 Siemens Healthcare Diagnostics Inc. Page 28Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Thank you for your attention!
Copyright © Siemens AG 2011. All rights reserved.
© 2011 Siemens Healthcare Diagnostics Inc. Page 29Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Contents
Goals
Brief Look on Siemens and Vector
Business and Environment
Quality Requirements Engineering
Results and Summary
Further Information
© 2011 Siemens Healthcare Diagnostics Inc. Page 30Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Documented Experiences and Best Practices from various Industry Projects
Link to web site McGrawHill
English language:
Software & Systems Requirements Engineering: In Practice
2009
McGrawHill
German language:
SystematischesRequirements Engineering
Third edition, 2010
Dpunkt.verlagLink to web site Dpunkt
© 2011 Siemens Healthcare Diagnostics Inc. Page 31Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Arnold RudorferProgram Manager Platform DevelopmentSiemens Healthcare Diagnostics62 Flanders Bartley RoadFlanders, NJ, 07836
Phone: +1 973 927 28 28Mobile: +1 609 954 23 84
Email:[email protected]
© 2011 Siemens Healthcare Diagnostics Inc. Page 32Arnold Rudorfer, Siemens Healthcare Diagnostics, Christof Ebert, Vector Consulting
Dr. Christof EbertManaging DirectorVector Consulting Services GmbH
Ingersheimerstrasse 24D-70499 Stuttgart
Phone: +49 711 – 80670-175Fax: +49 711 – 86070-444
Email:[email protected]