Mingshu Li

Phase distribution of software development effort

Effort distribution by phase or activity is an important but often overlooked aspect compared to other steps in the cost estimation process. Poor effort allocation is among the major root causes of rework due to insufficiently resourced early activities. This paper provides results of an empirical study on phase effort distribution data of 75 industry projects, from the China Software Benchmarking Standard Group (CSBSG) database. The phase effort distribution patterns and variation sources are presented, and analysis results show some consistency in effects of software size and team size on code and test phase distribution variations, and some considerable deviations in requirements, design, and transition phases, compared with recommendations in the COCOMO model. Finally, this paper discusses the major findings and threats to validity and presents general guidelines in directing effort allocation. Empirical findings from this study are beneficial for stimulating discussions and debates to improve cost estimation and benchmarking practices.

A survey on software cost estimation in the chinese software industry

Although a lot of attention has been paid to software cost estimation since 1960, making accurate effort and schedule estimation is still a challenge. To collect evidence and identify potential areas of improvement in software cost estimation, it is important to investigate the estimation accuracy, the estimation method used, and the factors influencing the adoption of estimation methods in current industry. This paper analyzed 112 projects from the Chinese software project benchmarking dataset and conducted questionnaire survey on 116 organizations to investigate the above information. The paper presents the current situations related to software project estimation in China and provides evidence-based suggestions on how to improve software project estimation. Our survey results suggest, e.g., that large projects were more prone to cost and schedule overruns, that most computing managers and professionals were neither satisfied nor dissatisfied with the project estimation, that very few organizations (15%) used model-based methods, and that the high adoption cost and insignificant benefit after adoption were the main causes for low use of model-based methods.

Pricing crowdsourcing-based software development tasks

Many organisations have turned to crowdsource their software development projects. This raises important pricing questions, a problem that has not previously been addressed for the emerging crowdsourcing development paradigm. We address this problem by introducing 16 cost drivers for crowdsourced development activities and evaluate 12 predictive pricing models using 4 popular performance measures. We evaluate our predictive models on TopCoder, the largest current crowdsourcing platform for software development. We analyse all 5,910 software development tasks (for which partial data is available), using these to extract our proposed cost drivers. We evaluate our predictive models using the 490 completed projects (for which full details are available). Our results provide evidence to support our primary finding that useful prediction quality is achievable (Pred(30)>0.8). We also show that simple actionable advice can be extracted from our models to assist the 430,000 developers who are members of the TopCoder software development market.

Investigating dependencies in software requirements for change propagation analysis

Context: The dependencies between individual requirements have an important influence on software engineering activities e.g., project planning, architecture design, and change impact analysis. Although dozens of requirement dependency types were suggested in the literature from different points of interest, there still lacks an evaluation of the applicability of these dependency types in requirements engineering. Objective: Understanding the effect of these requirement dependencies to software engineering activities is useful but not trivial. In this study, we aimed to first investigate whether the existing dependency types are useful in practise, in particular for change propagation analysis, and then suggest improvements for dependency classification and definition. Method: We conducted a case study that evaluated the usefulness and applicability of two well-known generic dependency models covering 25 dependency types. The case study was conducted in a real-world industry project with three participants who offered different perspectives. Results: Our initial evaluation found that there exist a number of overlapping and/or ambiguous dependency types among the current models; five dependency types are particularly useful in change propagation analysis; and practitioners with different backgrounds possess various viewpoints on change propagation. To improve the state-of-the-art, a new dependency model is proposed to tackle the problems identified from the case study and the related literature. The new model classifies dependencies into intrinsic and additional dependencies on the top level, and suggests nine dependency types with precise definitions as its initial set. Conclusions: Our case study provides insights into requirement dependencies and their effects on change propagation analysis for both research and practise. The resulting new dependency model needs further evaluation and improvement.

Requirement-centric traceability for change impact analysis: a case study

Requirement change occurs during the entire software lifecycle,which is not only inevitable but also necessary. However, uncontrolled requirementchange will lead to a huge waste of time and effort. Most studiesabout the change impact analysis assume changes take place in code, which resultsin the analysis only at the source code level and ignoring the requirementchange is the fundamental cause. This paper introduces a Requirement CentricTraceability (RCT) approach to analyze the change impact at the requirementlevel. The RCT combines with the requirement interdependency graph and dynamicrequirement traceability to identify the potential impact of requirementchange on the entire system in late phase. This approach has been successfullyapplied to a real-life project, and the benefits and lessons learned will also bediscussed.

An empirical study on evolution of API documentation

With the evolution of an API library, its documentation also evolves. The evolution of API documentation is common knowledge for programmers and library developers, but not in a quantitative form. Without such quantitative knowledge, programmers may neglect important revisions of API documentation, and library developers may not effectively improve API documentation based on its revision histories. There is a strong need to conduct a quantitative study on API documentation evolution. However, as API documentation is large in size and revisions can be complicated, it is quite challenging to conduct such a study. In this paper, we present an analysis methodology to analyze the evolution of API documentation. Based on the methodology, we conduct a quantitative study on API documentation evolution of five widely used real-world libraries. The results reveal various valuable findings, and these findings allow programmers and library developers to better understand API documentation evolution.

Software process management: practices in china

Software process management has been proven a useful means to help software organizations improve their development processes and produce high quality products. It focuses on providing process-related products and services to software developer. Chinese software industry is developing rapidly. Effective software process methods, technology and tools that help them produce quality products while reducing the costs are in desperate need. This paper discusses the current state of project management in Chinese software companies and presents a solution and practices meeting this need.

Process Trustworthiness as a Capability Indicator for Measuring and Improving Software Trustworthiness

Due to increasing system decentralization, component heterogeneity, and interface complexities, many trustworthiness challenges become more and more complicated and intertwined. Moreover, there is a lack of common understanding of software trustworthiness and its related development methodology. This paper reports preliminary results from an ongoing collaborative research project among 6 international research units, which aims at exploring theories and methods for enhancing existing software process techniques for trustworthy software development. The results consist in two parts: 1) the proposal of a new concept of Process Trustworthiness, as a capability indicator to measure the relative degree of confidence for certain software processes to deliver trustworthy software; and 2) the introduction of the architecture of a Trustworthy Process Management Framework (TPMF) toolkit for process runtime support in measuring and improving process trustworthiness in order to assess and assure software trustworthiness.

A risk-driven method for eXtreme programming release planning

XP (eXtreme Programming) has become popular for IID (Iteration and Increment Development). It is suitable for small teams, lightweight projects and vague/volatile requirements. However, some challenges are left to developers when they desire to practise XP. A critical one of them is constructing the release plan and negotiating it with customers. In this paper, we propose a risk-driven method for XP release planning. It has been applied in a case study and the results show the method is feasible and effective. XP practicers can follow it to decide a suitable release plan and control the development process.

Improving software testing process: feature prioritization to make winners of success-critical stakeholders

For a successful software project, acceptable quality must be achieved within an acceptable cost, demonstrating business value to customers and satisfactorily meeting delivery timeliness. Testing serves as the most widely used approaches to determine that the intended functionalities are performed correctly and achieve the desired level of services; however, it is also a labor‐intensive and expensive process during the whole software life cycle. Most current testing processes are often technique‐centered, rather than organized to maximize business value. In this article, we extend and elaborate the ‘4+1’ theoretical lenses of Value‐based Software Engineering (VBSE) framework in the software testing process; propose a multi‐objective feature prioritization strategy for testing planning and controlling, which aligns the internal testing process with value objectives coming from customers and markets. Our case study in a real‐life business project shows that this method allows reasoning about the software testing process in different dimensions: it helps to manage the testing process effectively and efficiently, provides information for continuous internal software process improvement, and increases customer satisfaction, which makes winners of all success‐critical stakeholders (SCSs) in the software testing process. Copyright