Quality Re Pres Ebert Rudorfer Med Conf2011 V4

© 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


Contents

Goals

Brief Look on Siemens and Vector

Business and Environment

Quality Requirements Engineering

Results and Summary

Further Information


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


Contents

Goals




Results and Summary

Further Information


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


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


Contents

Goals




Results and Summary

Further Information


Business Challenges

Environment: Shorten time-to-market Cuts in healthcare budgets Continuous product innovation


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


Contents

Goals




Results and Summary

Further Information


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


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


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



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



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



SecurityProtocolDesign

Specification

Test Cases

Simulation / Test

Test Results

Example: Simulation / test of a security protocolSystems

Engineering



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


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


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


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


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)


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


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 ...


Contents

Goals




Results and Summary

Further Information



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


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


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


Thank you for your attention!

Copyright © Siemens AG 2011. All rights reserved.


Contents

Goals




Results and Summary

Further Information


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


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]


Dr. Christof EbertManaging DirectorVector Consulting Services GmbH

Ingersheimerstrasse 24D-70499 Stuttgart

Phone: +49 711 – 80670-175Fax: +49 711 – 86070-444

Email:[email protected]

Date post:	01-Dec-2014
Category:	Documents
Upload:	arnold-rudorfer
View:	316 times
Download:	2 times

Quality Re Pres Ebert Rudorfer Med Conf2011 V4

Documents