DeSyRe: decomposition of systems and their requirements [Elektronische Ressource] : transition from system to subsystem using a criteria catalogue and systematic requirements refinement / Birgit Penzenstadler

Sujets

• Wissenschaft

Informations

• Publié par: technische_universitat_munchen
• Publié le: 01 janvier 2010
• Nombre de lectures: 27
• Langue: English
• Poids de l'ouvrage: 8 Mo

Extrait

Institut für Informatik
der Technischen Universität München
DeSyRe: Decomposition of Systems and their
Requirements
— Transition from System to Subsystem using
a Criteria Catalogue and Systematic
Requirements Refinement
Birgit Penzenstadler
Vollständiger Abdruck der von der Fakultät für Informatik der Technischen Universität
München zur Erlangung des akademischen Grades eines
Doktors der Naturwissenschaften (Dr. rer. nat.)
genehmigten Dissertation.
Vorsitzender: Univ.-Prof. Michael Beetz, Ph.D.
Prüfer der Dissertation:
1. Univ.-Prof. Dr. Dr. h.c. Manfred Broy
2. Dr. Barbara Paech, Ruprecht-Karls-Universität Heidelberg
Die Dissertation wurde am 21.10.2010 bei der Technischen Universität München
eingereicht und durch die Fakultät für Informatik am 19.12.2010 angenommen.Abstract
In software systems development, companies try to handle the increasing size
and complexity of their systems by signing up different subcontractors for
subsystems. For distributed development and smooth integration, a major
challenge is to deduce subsystem specifications from system specifications in
order to deliver them to the subcontractors. Thereby, thorough requirements
engineering lays the basis for successful systems’ development in such a
divide-and-conquer approach in order to provide a subcontractor with all
information they need.
Missing information within the subsystem requirements is the pitfall for
successful distributed development, so that either the subsystem requirements
do not fulfill the overall system requirements completely, or there is a mismatch
between subsystems during integration due to inconsistencies between the
specifications for the respective subsystems.
Consequently, the research objective of this work is to investigate how
a requirements engineer can systematically derive subsystem requirements
specifications from system requirements specifications. The guiding questions
are:
What is a good way for the system architect to obtain the initial system
decomposition?
What is a good way for the requirements engineer to deduce subsystem
requirements from system requirements?
How do the requirements engineer and the system architect perform both
the decomposition and deduction during the requirements specification
development process?
Currently, there is no encompassing approach in the literature that provides
guidance to systematic decomposition of systems and refinement of their
requirements to avoid loss of information.
This dissertation provides such guidance by means of a reference catalogue
of decomposition criteria and an approach to requirements decomposition and
refinement. The contributions are:
A reference criteria catalogue for initial system decomposition that serves
as extensive checklist during the first design step
An approach to systematically derive subsystem requirements from
system requirements by use of assumption / guarantee reasoning and
decomposition patterns
A process that exemplarily guides the application of the approach using a
requirements artifact model
The results are demonstrated using a running example from the automotive
domain and evaluated in an industrial case study with respect to applicability.Contents
1 Introduction 1
1.1 Motivation and Problem Statement . . . . . . . . . . . . . . . . . 1
1.2 Research Questions . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3h Design . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.4 Contribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.5 Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2 State of the Art 7
2.1 State of Practice in Automotive Software Development . . . . . . 7
2.2 Interview Study on the State of Practice . . . . . . . . . . . . . . 11
2.2.1 Context . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.2.2 Research Objective . . . . . . . . . . . . . . . . . . . . . . 12
2.2.3 Hypothesis . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.2.4 Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.2.5 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.2.6 Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.2.7 Validity of the Study . . . . . . . . . . . . . . . . . . . . . 16
2.2.8 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.3 Software Systems Architecture Model . . . . . . . . . . . . . . . 16
2.4 Requirements Engineering Reference Model . . . . . . . . . . . . 18
2.5 The REMsES Project . . . . . . . . . . . . . . . . . . . . . . . . 20
2.5.1 Structure Concepts . . . . . . . . . . . . . . . . . . . . . . 21
2.5.2 Specification Techniques . . . . . . . . . . . . . . . . . . . 24
2.5.3 Artifact Model . . . . . . . . . . . . . . . . . . . . . . . . 25
2.5.4 Results and Evaluation . . . . . . . . . . . . . . . . . . . 38
2.6 Example: Driver Assistance Systems . . . . . . . . . . . . . . . . 38
3 Decomposition Criteria 41
3.1 Related Work for the Decomposition of Systems . . . . . . . . . 41
3.2 Overview of the Criteria Catalogue . . . . . . . . . . . . . . . . . 43
3.2.1 Optimization Factors . . . . . . . . . . . . . . . . . . . . . 43
3.2.2 Criteria Categories . . . . . . . . . . . . . . . . . . . . . . 44
3.2.3 The Description Template . . . . . . . . . . . . . . . . . . 45
3.3 Directive Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
3.3.1 Organization . . . . . . . . . . . . . . . . . . . . . . . . . 48
3.3.2 Legislation . . . . . . . . . . . . . . . . . . . . . . . . . . 49
3.3.3 Economics . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
3.3.4 Directive Criteria of the Running Example . . . . . . . . 50
iCONTENTS ii
3.4 Functional Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . 50
3.4.1 Clustering According to Services . . . . . . . . . . . . . . 51
3.4.2 Functional Dependencies . . . . . . . . . . . . . . . . . . . 51
3.4.3 Unwanted Feature Interaction . . . . . . . . . . . . . . . . 52
3.4.4 Functional Criteria of the Running Example . . . . . . . . 52
3.5 Quality Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
3.5.1 Quality Criteria of the Running Example . . . . . . . . . 54
3.6 Technical Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
3.6.1 Communication Requirements . . . . . . . . . . . . . . . . 55
3.6.2 Technical Constraints . . . . . . . . . . . . . . . . . . . . 56
3.6.3 Legacy Systems . . . . . . . . . . . . . . . . . . . . . . . . 57
3.6.4 Technical Criteria of the Running Example . . . . . . . . 57
3.7 Coherence of the Criteria . . . . . . . . . . . . . . . . . . . . . . 58
3.7.1 Dependencies between Criteria . . . . . . . . . . . . . . . 58
3.8 Impact of the Criteria on Decomposition . . . . . . . . . . . . . . 60
4 Subsystem Requirements 62
4.1 Related Work for Subsystem Requirements . . . . . . . . . . . . 63
4.2 Prerequisites for Requirements Refinement . . . . . . . . . . . . . 65
4.2.1 Assumption / Guarantee Specifications . . . . . . . . . . 66
4.2.2 Semi-formal View of the Problem . . . . . . . . . . . . . . 67
4.3 Subsystem Modeling . . . . . . . . . . . . . . . . . . . . . . . . . 68
4.3.1 Definition of a Subsystem Model . . . . . . . . . . . . . . 69
4.3.2 Subsystem Distribution across Abstraction Levels . . . . . 71
4.3.3 Description Levels . . . . . 73
4.4 Refinement Application Guideline . . . . . . . . . . . . . . . . . . 74
4.5 Case Differentiation for Requirements Distribution . . . . . . . . 77
4.5.1 One-to-one Transition of Requirements . . . . . . . . . . . 77
4.5.2 One-to-many T ofts . . . . . . . . . 77
4.6 Decomposition and Refinement Patterns . . . . . . . . . . . . . . 78
4.6.1 Pipeline Decomposition Pattern . . . . . . . . . . . . . . . 80
4.6.2 Subserviceosition Pattern . . . . . . . . . . . . . 82
4.6.3 General Decomposition Pattern . . . . . . . . . . . . . . . 84
4.7 Discussion: Quality Requirements . . . . . . . . . . . . . . . . . . 87
4.7.1 Definition of Quality Requirements . . . . . . . . . . . . . 87
4.7.2 Precondition for Decomposition: Compositionality . . . . 88
4.7.3 Decomposition and Alternative Handling of Quality
Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 89
4.8 Tracing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
4.8.1 State of the Art of Tracing . . . . . . . . . . . . . . . . . 97
4.8.2 State of the Practice of Tracing . . . . . . . . . . . . . . . 98
4.8.3 Proposed Tracing Approach . . . . . . . . . . . . . . . . . 99
5 The DeSyRe Method 102
5.1 Related Work for the DeSyRe Approach . . . . . . . . . . . . . . 103
5.2 Outline of the DeSyRe Method Phases . . . . . . . . . . . . . . . 104
5.3 Starting Point: Required Artifacts . . . . . . . . . . . . . . . . . 106
5.4 Decomposition into Subsystems . . . . . . . . . . . . . . . . . . . 107
5.4.1 Consideration of the Reference Catalogue . . . . . . . . . 108
5.4.2 Decomposition Realization . . . . . . . . . . . . . . . . . 109CONTENTS iii
5.5 Transition to Subsystem Requirements . . . . . . . . . . . . . . . 112
5.5.1 Context . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
5.5.2 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 114
5.5.3 Design . . . . . . .