INSEAD Library

Includes bibliographical references and index

Includes chapter by Maxwell, Katrina "What you need to know about statistics" p. 365-408

Digitized

Web Engineering Table of Contents 1 The Need for Web Engineering: An Introduction......................... 1 1.1 Introduction .................................................................................. 1 1.2 Web Applications Versus Conventional Software....................... 3 1.2.1 Web Hypermedia, Web Software, or Web Application?...................................................... 3 1.2.2 Web Development vs. Software Development................. 4 1.3 The Need for an Engineering Approach..................................... 13 1.4 Empirical Assessment................................................................. 17 1.5 Conclusions.................................................................................. 24 Acknowledgements.................................................................. 24 References................................................................................ 24 Authors' Biographies................................................................ 26 Web Effort Estimation.................................................................... 29 2.1 Introduction.................................................................................. 29 2.2 Effort Estimation Techniques..................................................... 30 2.2.1 Expert Opinion................................................................ 31 2.2.2 Algorithmic Techniques.................................................. 32 2.2.3 Artificial Intelligence Techniques................................... 34 2.3 Measuring Effort Prediction Power and Accuracy...................... 39 2.3.1 Measuring Predictive Power............................................39 2.3.2 Measuring Predictive Accuracy...................................... 40 2.4 Which Is the Most Accurate Prediction Technique?................... 41 2.5 Case Study................................................................................... 42 2.5.1 Data Validation................................................................ 44 2.5.2 Variables and Model Selection........................................ 47 2.5.3 Extraction of effort Equation........................................... 67 2.5.4 Model Validation............................................................. 67 2.6 Conclusions.................................................................................. 69 References................................................................................ 70 Authors' Biographies................................................................ 73 2 3 Web Productivity Measurement and Benchmarking......................... 75 3.1 Introduction.................................................................................. 75 3.2 Productivity Measurement Method............................................. 76 3.3 Case Study................................................................................... 77 3.3.1 Productivity Measure Construction................................. 79 3.3.2 Productivity Analysis..................................................... 96 X Table of Contents 3.4 Conclusions................................................................................. References.............................................................................. Acknowledgements................................................................ Authors' Biographies.............................................................. 104 105 105 105 4 Web Quality..........................................................................................109 4.1 Introduction............................................................................... 109 4.2 Different Perspectives of Quality.............................................. 112 4.2.1 Standards and Quality................................................... 112 4.2.2 Quality Versus Quality in Use....................................... 116 4.2.3 Quality and User Standpoints........................................ 119 4.2.4 What is Web Quality?................................................... 120 4.3 Evaluating Web Quality using WebQEM................................. 123 4.3.1 Quality Requirements Definition and Specification........................................................ 125 4.3.2 Elementary Measurement and Evaluation..................... 125 4.3.3 Global Evaluation.......................................................... 128 4.3.4 Conclusions and Recommendations.............................. 129 4.3.5 Automating the Process using WebQEM_Tool............ 129 4.4 Case Study: Evaluating the Quality of Two Web Applications...................................................... 130 4.4.1 External Quality Requirements..................................... 130 4.4.2 Designing and Executing the Elementary Evaluation......................................... 131 4.4.3 Designing and Executing the Partial/Global Evaluation..................................... 134 4.4.4 Analysis and Recommendations................................... 136 4.5 Concluding Remarks................................................................. 139 Acknowledgements................................................................ 140 References.............................................................................. 140 Authors' Biographies.............................................................. 142 5 Web Usability: Principles and Evaluation Methods.................. 143 5.1 Introduction................................................................................ 143 5.1.1 Usability in the Software Lifecycle............................... 144 5.1.2 Chapter Organisation..................................................... 145 5.2 Defining Web Usability............................................................. 146 5.2.1 Usability and Accessibility............................................ 147 5.3 Web Usability Criteria............................................................... 149 5.3.1 Content Visibility.......................................................... 151 5.3.2 Ease of Content Access................................................. 153 5.3.3 Ease of Content Browsing............................................. 155 Table of Contents XI 5.4 Evaluation Methods.................................................................... 156 5.4.1 User Testing.................................................................. 157 5.4.2 Inspection Methods....................................................... 159 5.5 Automatic Tools To Support Evaluations.................................. 165 5.6 Evaluation of the DEI Application............................................. 166 5.6.1 Design Inspection......................................................... 167 5.6.2 Web Usage Analysis..................................................... 170 5.7 Concluding Remarks.................................................................. 173 References.............................................................................. 175 Authors' Biographies.............................................................. 179 6 Web System Reliability and Performance:................................. 181 6.1 Introduction............................................................................... 181 6.2 Web Application Services......................................................... 183 6.2.1 Web Resource Classification........................................ 184 6.2.2 Web Application's Bearing on System Resources........ 186 6.2.3 Workload Models and Performance Requirements...... 187 6.3 Applications Predominantly Dynamic...................................... 189 6.3.1 Dynamic Request Service............................................. 189 6.3.2 Software Technologies for the Application Logic ....... 190 6.3.3 System Platforms.......................................................... 193 6.4 Testing Loop Phase................................................................... 197 6.4.1 Representation of the Workload Model........................ 198 6.4.2 Traffic Generation......................................................... 199 6.4.3 Data Collection and Analysis........................................ 199 6.5 Performance Improvements...................................................... 203 6.5.1 System Tuning.............................................................. 203 6.5.2 System Scale-up............................................................204 6.5.3 System Scale-out...........................................................204 6.6 Case Study.................................................................................205 6.6.1 Service Characterisation and Design............................ 205 6.6.2 Testing Loop Phase.......................................................208 6.6.3 System Consolidation and Performance Improvement.............................................................. 212 6.7 Conclusions............................................................................... 214 Acknowledgements................................................................214 References.............................................................................. 214 Authors' Biographies.............................................................. 217 Web Application Testing...............................................................219 7.1 Introduction...............................................................................219 7.2 Web Application Testing: Challenges and Perspectives.......... 221 7 XII Table of Contents 7.2.1 Testing the Non-functional Requirements of a Web Application................................................. 222 7.2.2 Testing the Functional Requirements of a Web Application................................................. 225 7.3 Web Application Representation Models................................. 227 7.4 Unit Integration and System Testing of a Web Application............................................................. 230 7.4.1 Unit Testing...................................................................230 7.4.2 Integration Testing........................................................ 232 7.4.3 System Testing.............................................................. 233 7.5 Strategies for Web Application Testing.................................... 233 7.5.1 White Box Strategies.................................................... 234 7.5.2 Black Box Strategies.....................................................237 7.5.3 Grey Box Testing Strategies......................................... 241 7.5.4 User Session Based Testing.......................................... 242 7.6 Tools for Web Application Testing...........................................243 7.7 A Practical Example of Web Application Testing....................246 7.8 Conclusions............................................................................... 257 References.............................................................................. 258 Authors' Biographies..............................................................260 8 An Overview of Process Improvement in Small Settings..........261 8.1 Introduction............................................................................... 261 8.1.1 Why Do Organisations Initiate SPI Efforts?.................262 8.1.2 Process Improvement Cycle..........................................265 8.1.3 Process Assessments..................................................... 267 8.2 Implementation in Small Settings............................................. 269 8.2.1 Availability of Funds.....................................................269 8.2.2 Resources For Process Improvement............................269 8.2.3 Process Model............................................................... 270 8.2.4 Training......................................................................... 270 8.2.5 Relevance of Practices in Assessment Models............. 271 8.2.6 Changing Behaviour......................................................271 8.2.7 Piloting Practices...........................................................272 8.2.8 Where To Start.............................................................. 272 8.3 Conclusions............................................................................... 274 References....................................................................................... 274 Author's Biography......................................................................... 275 Conceptual Modelling of Web Applications: The OOWS Approach...................................................................277 9.1 Introduction............................................................................... 277 9.2 A Method to Model Web Applications..................................... 278 9 Table of Contents XIII 9.2.1 OO-Method Conceptual Modelling............................... 279 9.2.2 OOWS: Extending Conceptual Modelling to Web Environments................................................ 280 9.3 A Strategy To Develop the Web Solution................................ 286 9.4 Case Study: Valencia CF Web Application............................. 287 9.5 Conclusions...............................................................................300 References............................................................................. 300 Authors' Biographies............................................................. 301 10 Model-Based Web Application Development..................................303 10.1 The OOHDM approach ­ An Overview.................................303 10.1.1 Requirements Gathering.............................................304 10.1.2 Conceptual Design......................................................305 10.1.3 Navigational Design................................................... 305 10.1.4 Abstract Interface Design...........................................306 10.1.5 Implementation........................................................... 306 10.2 Building an Online CD Store with OOHDM..........................307 10.2.1 Requirements Gathering.............................................307 10.2.2 Conceptual Modelling................................................ 313 10.2.3 Navigation Design...................................................... 315 10.2.4 Abstract Interface Design...........................................321 10.3 From Design to Implementation............................................. 327 10.4 Discussion and Lessons Learned............................................ 331 10.5 Concluding Remarks.............................................................. 332 Acknowledgements............................................................... 332 References............................................................................. 332 Authors' Biography................................................................333 11 W2000: A Modelling Notation for Complex Web Applications..........................................................................335 11.1 Introduction............................................................................. 335 11.2 Modelling Elements................................................................337 11.3 Models.................................................................................... 341 11.3.1 Adaptability................................................................ 343 11.3.2 Tool Support............................................................... 346 11.4 Example Application.............................................................. 346 11.4.1 Information Model......................................................348 11.4.2 Navigation Model....................................................... 353 11.4.3 Presentation Model.....................................................356 11.4.4 Service Model.............................................................358 11.5 Conclusions and Future Work................................................ 362 References............................................................................. 362 Authors' Biographies............................................................. 363 XIV 12 What You Need To Know About Statistics......................................365 12.1 Describing Individual Variables............................................. 365 12.1.1 Types of Variables...................................................... 365 12.1.2 Descriptive Statistics................................................... 367 12.2 The Normal Distribution......................................................... 374 12.3 Overview of Sampling Theory............................................... 375 12.4 Other Probability Distributions............................................... 378 12.5 Identifying Relationships in the Data..................................... 379 12.5.1 Chi-Square Test for Independence............................. 380 12.5.2 Correlation Analysis................................................... 384 12.5.3 Regression Analysis.................................................... 390 12.5.4 Analysis of Variance (ANOVA).................................400 12.5.5 Comparing Two Estimation Models...........................405 12.5.6 Final Comments..........................................................407 Author's Biography................................................................407 13 Empirical Research Methods in Web and Software Engineering............................................................. 409 13.1 Introduction.............................................................................409 13.2 Overview of Empirical Methods.............................................411 13.3 Empirical Methods in an Improvement Context.....................415 13.4 Controlled Experiments.......................................................... 416 13.4.1 Introduction.................................................................416 13.4.2 Design......................................................................... 417 13.4.3 Operation.................................................................... 419 13.4.4 Analysis and Interpretation.........................................420 13.5 Case Study.............................................................................. 422 13.5.1 Introduction.................................................................422 13.5.2 Case Study Arrangements...........................................423 13.5.3 Confounding Factors and Other Aspects.................... 423 13.6 Survey..................................................................................... 424 13.6.1 Survey Characteristics................................................ 424 13.6.2 Survey Purposes..........................................................425 13.6.3 Data Collection........................................................... 426 13.7 Post-mortem Analysis.............................................................426 13.8 Summary................................................................................. 428 References............................................................................. 428 Authors Biographies.............................................................. 429