Development of software for structural analysis adapted to construction engineering applications

The paper presents the development and application of software for structural analysis adapted to construction engineering applications. The software consists of data structures, application subroutine libraries and the built-in Matlab subroutine library. For each application, the user writes an application-specific main program using the data structures and routines in the subroutine libraries. This gives the user flexibility to build a main program that is adapted to the specific needs of the current application. The software has been tested in a number of real-world projects, e.g. tunnels and bridges. The examples show that the software is a useful design tool for design work.     

A tabu search algorithm for structural software testing

This paper presents a tabu search metaheuristic algorithm for the automatic generation of structural software tests. It is a novel work since tabu search is applied to the automation of the test generation task, whereas previous works have used other techniques such as genetic algorithms. The developed test generator has a cost function for intensifying the search and another for diversifying the search that is used when the intensification is not successful. It also combines the use of memory with a backtracking process to avoid getting stuck in local minima. Evaluation of the generator was performed using complex programs under test and large ranges for input variables. Results show that the developed generator is both effective and efficient.     

A binomial software reliability model based on coverage of structural testing criteria

A new approach to software reliability modeling is discussed where variables indirectly related with software reliability are used to provide additional information for the modeling process. Previous studies, empirical and theoretical evidences, and results from experiments indicate that there is a strong relationship between software reliability and coverage of program elements required to be exercised by structural testing criteria. This paper develops a binomial type coverage-based software reliability model through the definition of a coverage-based failure rate function. The Binomial software reliability Model Based on Coverage—BMBC—is proposed and discussed. In the BMBC test data between failures is used instead of time as independent variable; the model was assessed with test data from a real application, making use of the following structural testing criteria: all-nodes, all-edges, and potential-uses—a data-flow based family of testing criteria. The results from our experiments have shown that our modeling approach has some advantages over some traditional reliability models and points to a very promising research direction in software reliability.

Visualizing protected variations in evolving software designs

Identifying and tracking evolving software structures at a design level is a challenging task. Although there are ways to visualize this information statically, there is a need for methods that help analyzing the evolution of software design elements. In this paper, we present a new visual approach to identify variability zones in software designs and explore how they evolve over time. To verify the usefulness of our approach, we did a user study in which participants had to browse software histories and find visual patterns. Most participants were able to find interesting observations and found our approach intuitive and useful. We present a number of design aspects that were observed by participants and the authors using our IHVis tool on four open-source projects.     

Studying software evolution using artefacts’ shared information content

In order to study software evolution, it is necessary to measure artefacts representative of project releases. If we consider the process of software evolution to be copying with subsequent modification, then, by analogy, placing emphasis on what remains the same between releases will lead to focusing on similarity between artefacts. At the same time, software artefacts-stored digitally as binary strings-are all information. This paper introduces a new method for measuring software evolution in terms of artefacts’ shared information content. A similarity value representing the quantity of information shared between artefact pairs is produced using a calculation based on Kolmogorov complexity. Similarity values for releases are then collated over the software’s evolution to form a map quantifying change through lack of similarity. The method has general applicability: it can disregard otherwise salient software features such as programming paradigm, language or application domain because it considers software artefacts purely in terms of the mathematically justified concept of information content. Three open-source projects are analysed to show the method’s utility. Preliminary experiments on udev and git verify the measurement of the projects’ evolutions. An experiment on ArgoUML validates the measured evolution against experimental data from other studies.     

An empirical study of fine-grained software modifications

Software is typically improved and modified in small increments (we refer to each of these increments as a modification record—MR). MRs are usually stored in a configuration management or version control system and can be retrieved for analysis. In this study we retrieved the MRs from several mature open software projects. We then concentrated our analysis on those MRs that fix defects and provided heuristics to automatically classify them. We used the information in the MRs to visualize what files are changed at the same time, and who are the people who tend to modify certain files. We argue that these visualizations can be used to understand the development stage of in which a project is at a given time (new features are added, or defects are being fixed), the level of modularization of a project, and how developers might interact between each other and the source code of a system.     

A conceptual model of software testing

As code is executed correctly under test, confidence in the correctness of the code increases. In this context, an intuitive conceptual model of the process of software testing which draws upon experience gained with mutation analysis is presented. The model is used to explain how the testing of one path can influence confidence in other (possibly unexecuted) paths. It is also discussed in relation to software reliability and systematic structural testing, and is shown to be consistent with observations made during these forms of testing.     

用PSP塑造合格的软件工程师

本文首先简要介绍了PSP的原理,阐述了如何使学生理解从个体软件开发过程到软件产品工程过程,培养学生从开发简单小程序的实践转向开发大规模软件。然后结合实际的教学环境对教学策略加以详细的说明,并对收集到的学生数据进行总结和分析。     

The evaluation of software systems' structure using quantitative software metrics

The design and analysis of the structure of software systems has typically been based on purely qualitative grounds. In this paper we report on our positive experience with a set of quantitative measures of software structure. These metrics, based on the number of possible paths of information flow through a given component, were used to evaluate the design and implementation of a software system (the UNIX operating system kernel) which exhibits the interconnectivity of components typical of large-scale software systems. Several examples are presented which show the power of this technique in locating a variety of both design and implementation defects. Suggested repairs, which agree with the commonly accepted principles of structured design and programming, are presented. The effect of these alterations on the structure of the system and the quantitative measurements of that structure lead to a convincing validation of the utility of information flow metrics.     

Macro-level software evolution: a case study of a large software compilation

Software evolution studies have traditionally focused on individual products. In this study we scale up the idea of software evolution by considering software compilations composed of a large quantity of independently developed products, engineered to work together. With the success of libre (free, open source) software, these compilations have become common in the form of ‘software distributions’, which group hundreds or thousands of software applications and libraries into an integrated system. We have performed an exploratory case study on one of them, Debian GNU/Linux, finding some significant results. First, Debian has been doubling in size every 2 years, totalling about 300 million lines of code as of 2007. Second, the mean size of packages has remained stable over time. Third, the number of dependencies between packages has been growing quickly. Finally, while C is still by far the most commonly used programming language for applications, use of the C++, Java, and Python languages have all significantly increased. The study helps not only to understand the evolution of Debian, but also yields insights into the evolution of mature libre software systems in general.

The Small Project Observatory: Visualizing software ecosystems

Software evolution research has focused mostly on analyzing the evolution of single software systems. However, it is rarely the case that a project exists as standalone, independent of others. Rather, projects exist in parallel within larger contexts in companies, research groups or even the open-source communities. We call these contexts software ecosystems. In this paper, we present the Small Project Observatory, a prototype tool which aims to support the analysis of software ecosystems through interactive visualization and exploration. We present a case study of exploring an ecosystem using our tool, we describe the architecture of the tool, and we distill lessons learned during the tool-building experience.     

Risk of using pirated software and its impact on software protection strategies

The software protection strategy of software developer and the inherent risk to end user in using pirated software are two major factors that affect a user's decision on whether to purchase or pirate a software product. This paper analyzes the optimal protection strategy for software developer in horizontally and vertically differentiated markets. We find that the implementation cost of software protection constitutes the primary factor for software developers to determine their software protection strategies. However, in a vertically differentiated market, the lower quality product should always adopt a non-protection strategy, regardless of the protection implementation cost. In other cases, protection would only be optimal if the protection implementation cost to the software developer is relatively small. These findings are consistent with anecdotal evidence.     

Generalized approximate regularities in strings

We concentrate on generalized string regularities and study the minimum approximate λ-cover problem and the minimum approximate λ-seed problem of a string. Given a string x of length n and an integer λ, the minimum approximate λ-cover (respectively, seed) problem is to find a set of λ substrings each of equal length that covers x (respectively, a superstring of x) with the minimum error, under a variety of distance models containing the Hamming distance, the edit distance and the weighted edit distance. Both problems can be solved in polynomial time.     

Characterization of contour regularities based on the Levenshtein edit distance

This paper describes a new method for quantifying the regularity of contours and comparing them (when encoded by Freeman chain codes) in terms of a similarity criterion which relies on information gathered from Levenshtein edit distance computation. The criterion used allows subsequences to be found from the minimal cost edit sequence that specifies an alignment of contour segments which are similar. Two external parameters adjust the similarity criterion. The information about each similar part is encoded by strings that represent an average contour region. An explanation of how to construct a prototype based on the identified regularities is also reviewed. The reliability of the prototypes is evaluated by replacing contour groups (samples) by new prototypes used as the training set in a classification task. This way, the size of the data set can be reduced without sensibly affecting its representational power for classification purposes. Experimental results show that this scheme achieves a reduction in the size of the training data set of about 80% while the classification error only increases by 0.45% in one of the three data sets studied.     

The changing industry structure of software development for consumer electronics and its consequences for software architectures

During the last decade the structure of the consumer electronics industry has been changing profoundly. Current consumer electronics products are built using components from a large variety of specialized firms, whereas previously each product was developed by a single, vertically integrated company. Taking a software development perspective, we analyze the transition in the consumer electronics industry using case studies from digital televisions and mobile phones. We introduce a model consisting of five industry structure types and describe the forces that govern the transition between types and we describe the consequences for software architectures.We conclude that, at this point in time, software supply chains are the dominant industry structure for developing consumer electronics products. This is because the modularization of the architecture is limited, due to the lack of industry-wide standards and because resource constrained devices require variants of supplied software that are optimized for different hardware configurations. Due to these characteristics open ecosystems have not been widely adopted. The model and forces can serve the decision making process for individual companies that consider the transition to a different type of industry structure as well as provide a framework for researchers studying the software-intensive industries.     

Alignment within the software development unit: Assessing structural and relational dimensions between developers and testers

Just as business-IT alignment has received significant focus as a strategic concern in the IS literature, it is also important to consider internal alignment between the diverse subunits within the IT organization. This study investigates alignment between developers and testers in software development to understand alignment within the IT unit. Prior evidence of tension between these sub-groups (and others as well) suggests that all is not necessarily well within the IT organization. Misalignment within the IT unit can certainly make it difficult for the IT unit to add strategic value to the organization. This study is an important initial step in investigating IT subunit alignment which can inform future research focusing on the alignment of other IT subunits such as architecture, operations, and customer-support. Using theoretical concepts from strategic business-IT alignment, we test a research model through a survey of professional software developers and testers. Results suggest that relational but not structural dimensions influence IT subunit alignment.     

The adoption of software measures: A technology acceptance model (TAM) perspective

The use of software measures for project management and software process improvement has been encouraged for many years. However, the low level of acceptance and use of software measures in practice has been a constant concern. In this paper we propose and test a model which explains and predicts the use of software measures. The model is based on the technology acceptance model (TAM) and operationalizes the perceived usefulness construct according to the “desirable properties of software measures.” Our research provides guidance for software engineers in selecting among different software measures and for software metrics coordinators who are planning measurement programs.     

A systematic review of software architecture evolution research

Context

Software evolvability describes a software system’s ability to easily accommodate future changes. It is a fundamental characteristic for making strategic decisions, and increasing economic value of software. For long-lived systems, there is a need to address evolvability explicitly during the entire software lifecycle in order to prolong the productive lifetime of software systems. For this reason, many research studies have been proposed in this area both by researchers and industry practitioners. These studies comprise a spectrum of particular techniques and practices, covering various activities in software lifecycle. However, no systematic review has been conducted previously to provide an extensive overview of software architecture evolvability research.

Objective

In this work, we present such a systematic review of architecting for software evolvability. The objective of this review is to obtain an overview of the existing approaches in analyzing and improving software evolvability at architectural level, and investigate impacts on research and practice.

Method

The identification of the primary studies in this review was based on a pre-defined search strategy and a multi-step selection process.

Results

Based on research topics in these studies, we have identified five main categories of themes: (i) techniques supporting quality consideration during software architecture design, (ii) architectural quality evaluation, (iii) economic valuation, (iv) architectural knowledge management, and (v) modeling techniques. A comprehensive overview of these categories and related studies is presented.

Conclusion

The findings of this review also reveal suggestions for further research and practice, such as (i) it is necessary to establish a theoretical foundation for software evolution research due to the fact that the expertise in this area is still built on the basis of case studies instead of generalized knowledge; (ii) it is necessary to combine appropriate techniques to address the multifaceted perspectives of software evolvability due to the fact that each technique has its specific focus and context for which it is appropriate in the entire software lifecycle.