A Rationale-based Model for Architecture Design Reasoning

More documents

Recommendations

Info

2.1. Industry practice of design rationale be more than one answer and most likely the answers are non-trivial. However, there is something fundamental that underlies such project issues - the soundness of the design decisions. Software engineering practices mostly focus on the design of concrete and visible artefacts and either omit or treat the decision making documentation as separate [43]. Design rationale is commonly ignored and undocumented. Most of the time they are not mandated as part of the software deliverable. Even though architecture design is thought to be a very important stage in the development process, the architecture design rationale are usually not rigorously tested in the design review process. The treatment of those factors which influence the design decisions are usually implicit and ad hoc. For instance, architecture decisions would make assumptions on factors such as delivery schedule, level of expertise in the development team and platform stability, but these assumptions are mostly implicit. Designers could be biased toward personal preferences and agenda that would affect the objectivity of the design decisions. Given that design decisions are predominantly an implicit process, it is possible and quite common that a series of incorrect decisions can escape quality checks set out by development methodologies and standards, resulting in project failures. Thus we posit that improving the decision making process can help minimise mistakes and failures. Along with many other researchers [11, 12, 124], we argue that making quality decisions is an essential part of software development. High quality design requires that each decision is rational and that all relevant factors which influence the decision are well considered. As such, the system design process will improve if a methodology to enhance design decision making is available. In a successful project, planning and architecture design are two of the crucial steps [154]. These two factors are interrelated in that the project plans set the constraints for the architecture design, and the architecture design dictates the resources required in a project. For instance, design decisions made during the architecture design dictate the resources required to develop the system. Even though the role of architecture design is very important in a project, its decisions are often not sufficiently justified. Less than optimal decisions could be made and risk could arise when decisions are not justified systematically. The author has numerous encounters of such incidents and some real-life examples are illustrated below: • Design for the Future - arguing for reusability or flexibility, the architects make architecture design overly complex and costly without delivering additional benefits. The reusable or flexible features are actually never required or necessary [15]. 13
2.2. Architecture frameworks and design rationale • Schedule Constraints - management may have a budget and schedule constraint on the project. In view of such constraints, architecture designs are compromised to meet the schedule. The opportunity cost incurred is that the future enhancements are more costly [98]. • Platform Selection - selecting a software platform such as a database system is sometimes influenced by reasons that are not technical or financial in nature. It could be due to political reasons. As such, non-functional requirements such as performance, security and features that are essential to satisfy system requirements can be overlooked and compromised [98]. • Design Choices - the choice of a technical design may be influenced by architects’ familiarity with certain technologies. It may be a subjective opinion based on what designers are comfortable with rather than an objective rationale to measure the effectiveness of a solution. On the other hand, some architects may choose to use a new technology not because it is a suitable solution but because the architects want to gain experience in such technologies. Mystical software architectures without justified design decisions are quite common [170]. Creators of such architectures seem to want the project stakeholders to take many things on faith. There are many assumptions about the architecture that it could satisfy the business drivers, deliver the requirements and are implementable. Defects might be entrenched in the architecture design unknowingly. Existing quality and software engineering methodologies might not be able to detect these defects because design decisions are unjustified and undocumented. Design rationale are implicit in the design process and are probably not captured systematically, so they do not persist and can be lost over time. In order to address the issue of design knowledge evaporation, we study the process of architecture design rationalisation and the retention of design rationale. 2.2 Architecture frameworks and design rationale Software systems are becoming more complex as more components are used in their construction, thus the organisation of the overall system - the software architecture - presents a new set of design problems [46]. With that complexity, changes in an architecture are more difficult because they would affect a large part of the system [105]. To manage the complexity in architecture design, a number of architecture frameworks [21, 31, 30] and research work [119, 46, 147, 90, 85] have been devoted to this subject. A common approach to organising system components in an architecture is by using 14
Page 1 and 2: A Rationale-based Model for Archite
Page 3 and 4: maintenance. These techniques can h
Page 5 and 6: Declaration This thesis contains no
Page 7 and 8: 2.2.6 DoD Architecture Framework .
Page 9 and 10: 5.4.6 Risk assessment in architectu
Page 11 and 12: 8.2 The architecture rationalisatio
Page 13 and 14: 12.2 Contributions . . . . . . . .
Page 15 and 16: 6.10 ≪AR≫ and ≪AAR≫ Stereot
Page 17 and 18: 11.13A Process to Synchronise Chang
Page 19 and 20: 5.13 Design Rationale Helps Evaluat
Page 21 and 22: that architecture design is highly
Page 23 and 24: 1.2. Research motivations and resea
Page 25 and 26: 1.2. Research motivations and resea
Page 27 and 28: 1.4. Structure of the thesis the ch
Page 29 and 30: Part I Problem Analysis 10
Page 31: 2.1. Industry practice of design ra
Page 35 and 36: 2.2. Architecture frameworks and de
Page 43 and 44: Chapter 3 Related work in design ra
Page 45 and 46: 3.2. Why do we need design rational
Page 47 and 48: 3.2. Why do we need design rational
Page 49 and 50: 3.3. Existing methods for capturing
Page 57 and 58: 3.4. Other related studies 3.3.7 Qu
Page 59 and 60: 3.4. Other related studies evolutio
Page 61 and 62: 3.5. How well design rationale meth
Page 63 and 64: 3.5. How well design rationale meth
Page 65 and 66: Chapter 4 Research methodology and
Page 67 and 68: 4.1. Software engineering research
Page 69 and 70: 4.2. The chosen research and valida
Page 71 and 72: Part II Architecture Design Rationa
Page 73 and 74: on a regular basis. Their inputs ha
Page 75 and 76: 5.1. Architecture rationale in the
Page 77 and 78: 5.2. Survey methodology data collec
Page 79 and 80: 5.3. Survey findings experience). I
Page 81 and 82: 5.3. Survey findings Table 5.1: Fre
Page 83 and 84:
5.3. Survey findings Business Goals
Page 85 and 86:
5.3. Survey findings 5.3.5 Document
Page 87 and 88:
5.3. Survey findings Table 5.8 summ
Page 89 and 90:
5.3. Survey findings We used Spearm
Page 91 and 92:
5.3. Survey findings previous desig
Page 93 and 94:
5.4. Discussion of findings Since t
Page 95 and 96:
5.4. Discussion of findings or cons
Page 97 and 98:
5.5. Limitations and use design rat
Page 99 and 100:
Part III The Representation and App
Page 101 and 102:
6.1. A conceptual model for design
Page 103 and 104:
6.2. Architecture Rationale and Ele
Page 105 and 106:
6.2. Architecture Rationale and Ele
Page 107 and 108:
6.3. Architecture elements Figure 6
Page 109 and 110:
6.4. Architecture rationale Figure
Page 111 and 112:
6.4. Architecture rationale • ris
Page 113 and 114:
6.4. Architecture rationale depicts
Page 115 and 116:
6.5. The extended AREL To prevent c
Page 117 and 118:
6.6. A UML representation of AREL a
Page 119 and 120:
6.6. A UML representation of AREL a
Page 121 and 122:
6.7. AREL usability AE by ≪AEsupe
Page 123 and 124:
6.8. Summary The AREL model is exte
Page 125 and 126:
7.1. The EFT system reasoning, a co
Page 127 and 128:
7.1. The EFT system The processing
Page 129 and 130:
7.1. The EFT system not chosen beca
Page 131 and 132:
7.1. The EFT system Figure 7.5: Int
Page 133 and 134:
7.1. The EFT system sequence checki
Page 135 and 136:
7.1. The EFT system Figure 7.7: Dec
Page 137 and 138:
7.1. The EFT system Therefore, in a
Page 139 and 140:
7.1. The EFT system Figure 7.10: De
Page 141 and 142:
7.2. An empirical study to validate
Page 143 and 144:
Page 145 and 146:
Page 147 and 148:
Page 149 and 150:
Page 151 and 152:
7.3. Summary The case study is spec
Page 153 and 154:
8.1. Background Based on these assu
Page 155 and 156:
8.2. The architecture rationalisati
Page 157 and 158:
Page 159 and 160:
Page 161 and 162:
Page 163 and 164:
8.3. Other applications of ARM As d
Page 165 and 166:
8.3. Other applications of ARM Figu
Page 167 and 168:
8.3. Other applications of ARM area
Page 169 and 170:
Chapter 9 Architecture rationale an
Page 171 and 172:
9.1. Background 9.1 Background In t
Page 173 and 174:
9.2. Traceability of architecture r
Page 175 and 176:
9.4. AREL and eAREL traceability ap
Page 177 and 178:
Page 179 and 180:
Page 181 and 182:
Page 183 and 184:
Page 185 and 186:
Chapter 10 Architecture decision de
Page 187 and 188:
10.1. Background 10.1.2 Introductio
Page 189 and 190:
10.2. Building a BBN to represent a
Page 191 and 192:
Page 193 and 194:
Page 195 and 196:
Page 197 and 198:
10.3. Reasoning about change impact
Page 199 and 200:
Page 201 and 202:
Page 203 and 204:
Page 205 and 206:
Page 207 and 208:
Page 209 and 210:
10.5. Summary design object may cau
Page 211 and 212:
11.1. Capturing architecture design
Page 213 and 214:
11.1. Capturing architecture design
Page 215 and 216:
11.2. Checking AREL models Figure 1
Page 217 and 218:
11.3. Tracing AREL models Figure 11
Page 219 and 220:
11.4. Analysing AREL with BBN • S
Page 221 and 222:
11.5. Limitations Figure 11.13: A P
Page 223 and 224:
Chapter 12 Conclusions 12.1 Summary
Page 225 and 226:
12.2. Contributions reasoning metho
Page 227 and 228:
12.2. Contributions implementations
Page 229 and 230:
12.3. Future work architecture deci
Page 231 and 232:
12.3. Future work to examine the co
Page 233 and 234:
BIBLIOGRAPHY [10] B. W. Boehm, Soft
Page 235 and 236:
BIBLIOGRAPHY [37] A. Eden and R. Ka
Page 237 and 238:
BIBLIOGRAPHY [62] J. D. Herbsleb an
Page 239 and 240:
BIBLIOGRAPHY [89] N. Lassing, D. Ri
Page 241 and 242:
BIBLIOGRAPHY [115] D. L. Parnas,
Page 243 and 244:
BIBLIOGRAPHY [142] Z. Simsek and J.
Page 245 and 246:
BIBLIOGRAPHY [167] W. F. Tichy, N.
Page 247 and 248:
Appendix A AREL Tool User Manual 1
Page 249 and 250:
4.1 AREL Check Model When the Check
Page 251 and 252:
4.2 AREL Model Tracing AREL model t
Page 253 and 254:
Figure 9 - result of downward trace
Page 255 and 256:
To initiate the graph’s creation,
Page 257 and 258:
onto the diagram 14 Assign values t
Page 259 and 260:
Useful Definitions The following ar
Page 261 and 262:
) Some projects only c) Not at all
Page 263 and 264:
19. I revisit architecture design d
Page 265 and 266:
Complaint Procedure If you have any
Page 267 and 268:
Privacy Protection Only investigato
Page 269 and 270:
B. Exploring design reasoning. 1. W
Page 271 and 272:
3. Why does the system use asynchro
Page 273 and 274:
C. General Comments on AREL Modelli
Page 275:
IEEE Computer Society Press. A. Tan
show all

A Rationale-based Model for Architecture Design Reasoning

Create successful ePaper yourself

Delete template?

Save as template?