Danilo Caivano

Iterative reengineering of legacy systems

During its life, a legacy system is subjected to many maintenance activities, which cause degradation of the quality of the system: When this degradation exceeds a critical threshold, the legacy system needs to be reengineered. In order to preserve the asset represented by the legacy system, the familiarity with it gained by the systems maintainers and users, and the continuity of execution of current operations during the reengineering process, the system needs to be reengineered gradually. Moreover, each program needs to be reengineered within a short period of time. The paper proposes a reengineering process model, which is applied to an in-use legacy system to confirm that the process satisfies previous requirements and to measure its effectiveness. The reengineered system replaced the legacy one to the satisfaction of all the stakeholders; the reengineering process also had a satisfactory impact on the quality of the system. Finally, this paper contributes to validate the cause-effect relationship between the reengineering process and overcoming the aging symptoms of a software system.

Investigating and promoting UX practice in industry: an experimental study

Abstract The efforts of addressing user experience (UX) in product development keep growing, as demonstrated by the proliferation of workshops and conferences bringing together academics and practitioners, who aim at creating interactive software able to satisfy their users. This special issue focuses on “Interplay between User Experience Evaluation and Software Development”, stating that the gap between human-computer interaction and software engineering with regard to usability has somewhat been narrowed. Unfortunately, our experience shows that software development organizations perform few usability engineering activities or none at all. Several authors acknowledge that, in order to understand the reasons of the limited impact of usability engineering and UX methods, and to try to modify this situation, it is fundamental to thoroughly analyze current software development practices, involving practitioners and possibly working from inside the companies. This article contributes to this research line by reporting an experimental study conducted with software companies. The study has confirmed that still too many companies either neglect usability and UX, or do not properly consider them. Interesting problems emerged. This article gives suggestions on how they may be properly addressed, since their solution is the starting point for reducing the gap between research and practice of usability and UX. It also provides further evidence on the value of the research method, called Cooperative Method Development, based on the collaboration of researchers and practitioners in carrying out empirical research; it has been used in a step of the performed study and has revealed to be instrumental for showing practitioners why to improve their development processes and how to do so.

Evaluating software degradation through entropy

Software systems are affected by degradation as an effect of continuous change. Since late interventions are too much onerous, software degradation should be detected early in the software lifetime. Software degradation is currently detected by using many different complexity metrics, but their use to monitor maintenance activities is costly. These metrics are difficult to interpret, because each emphasizes a particular aspect of degradation and the aspects shown by different metrics are not orthogonal. The purpose of our research is to measure the entropy of a software system to assess its degradation. In this paper, we partially validate the entropy class of metrics by a case study, replicated on successive releases of a set of software systems. The validity is shown through direct measures of software quality, such as the number of detected defects, the maintenance effort and the number of slipped defects.

Prediction Models for BPMN Usability and Maintainability

The measurement of a business process in the earlystages of the lifecycle, such as the design andmodelling stages, could reduce costs and effort infuture maintenance tasks. In this paper we present aset of measures for assessing the structural complexityof business processes models at a conceptual level. Theaim is to obtain useful information about processmaintenance and to estimate the quality of the processmodel in the early stages. Empirical validation of themeasures was carried out along with a linearregression analysis aimed at estimating process modelquality in terms of modifiability and understandability.

Assessing the Influence of Stereotypes on the Comprehension of UML Sequence Diagrams: A Controlled Experiment

The main goal of this paper is to provide empirical evidence, through a controlled experiment, of the influence of stereotypes when modelers, developers, and maintainers have to comprehend UML sequence diagrams. The comprehension of UML sequence diagrams with and without stereotypes was analyzed from three different perspectives: semantic comprehension, retention and transfer. The experiment was carried out with 77 fourth year undergraduate students of Computer Science from the University of Bari in Italy. The results obtained show a slight tendency in favor of the use of stereotypes in facilitating the comprehension of UML sequence diagrams, although it is not statistically significant. Further replications are needed to obtain more conclusive results.

Harmonization of ISO/IEC 9001: 2000 and CMMI-DEV: from a theoretical comparison to a real case application

In the past years, both industrial and research communities in Software Engineering have shown special interest in Software Process Improvement—SPI. This is evidenced by the growing number of publications on the topic. The literature offers numerous quality frameworks for addressing SPI practices, which may be classified into two groups: ones that describe “what” should be done (ISO 9001, CMMI) and ones that describe “how” it should be done (Six Sigma, Goal Question Metrics-GQM). When organizations decide to adopt improvement initiatives, many models may be implied, each leveraging the best practices provided, in the quest to address the improvement challenges as well as possible. This may at the same time, however, generate confusion and overlapping activities, as well as extra effort and cost. That, in turn, risks generating a series of inefficiencies and redundancies that end up leading to losses rather than to effective process improvement. Consequently, it is important to move toward a harmonization of quality frameworks, aiming to identify intersections and overlapping parts, as well as to create a multi-model improvement solution. Our aim in this work is twofold: first of all, we propose a theoretical harmonization process that supports organizations interested in introducing quality management and software development practices or concerned about improving those they already have. This is done with specific reference to CMMI-DEV and ISO 9001 models in the direction “ISO to CMMI-DEV”, showing how GQM is used to define operational goals that address ISO 9001 statements, reusable in CMMI appraisals. Secondly, we apply the theoretical comparison process to a real case, i.e., a Small Enterprise certified ISO 9001.

Assessing the influence of stereotypes on the comprehension of UML sequence diagrams: A family of experiments

Context: The conventional wisdom states that stereotypes are used to clarify or extend the meaning of model elements and consequently should be helpful in comprehending the diagram semantics. Objective: The main goal of this work is to present a family of experiments that we have carried out to investigate whether the use of stereotypes improves the comprehension of UML sequence diagrams. Method: The family of experiments consists of an experiment and two replications carried out with 78, 29 and 36 undergraduate Computer Science students, respectively. The comprehension of UML sequence diagrams with and without stereotypes was analyzed from three different perspectives borrowed from the Cognitive Theory of Multimedia Learning (CTML): semantic comprehension, retention and transfer. In addition, we carried out a meta-analysis study to integrate the different data samples. Results: The statistical analysis and meta-analysis of the data obtained from each experiment separately indicates that the use of the proposed stereotypes helps improving the comprehension of the diagrams, especially when the subjects are not familiar with the domain. Conclusions: The set of stereotypes presented in this work seem to be helpful for a better comprehension of UML sequence diagrams, especially with not well-known domains. Although further research is necessary for strengthening these results, introducing these stereotypes both in academia and industry could be an interesting practice for checking the validity of the results.

An industrial case study on reuse oriented development

Software reuse can become a key factor for improving and guaranteeing software quality, when adopted systematically all along the software process. The main characteristic of reuse-oriented processes is that they require a common repository for storing, searching and retrieving software modules. Moreover, reuse occurs systematically and is an integrated part of the process. Previous works of the same authors have empirically shown that the full reuse maintenance model (FRM) slows down quality degradation following to maintenance interventions on a software system. This work is a further step in the investigation towards demonstrating how reuse oriented development (ROD) impacts on software quality; how it favors FRM model; and finally, whether reuse-oriented development influences productivity, and as so, is more efficient. This has been done through a case study carried out on two ongoing industrial projects. Results are positive and support our research hypotheses.

Managing Software Process Improvement (SPI) through Statistical Process Control (SPC)

Measurement based software process improvement is nowadays a mandatory activity. This implies continuous process monitoring in order to predict its behavior, highlight its performance variations and, if necessary, quickly react to them. Process variations are due to common causes or assignable ones. The former are part of the process itself while the latter are due to exceptional events that result in an unstable process behavior and thus in less predictability. Statistical Process Control (SPC) is a statistical based approach able to determine whether a process is stable or not by discriminating between the presence of common cause variation and assignable cause variation. It is a well-established technique, which has shown to be effective in manufacturing processes but not yet in software process contexts. Here experience in using SPC is not mature yet. Therefore a clear understanding of the SPC outcomes still lacks. Although many authors have used it in software, they have not considered the primary differences between manufacturing and software process characteristics. Due to such differences the authors sustain that SPC cannot be adopted as is but must be tailored. In this sense, we propose an SPC-based approach that reinterprets SPC, and applies it from a Software Process point of view. The paper validates the approach on industrial project data and shows how it can be successfully used as a decision support tool in software process improvement.

Method and process for iterative reengineering of data in a legacy system

This paper presents an iterative approach to database reengineering, starting from the assumption that for the user organization, the data are the most important assets in a legacy system. The most innovative feature of the proposed approach, in comparison with other rival approaches, is that it can eliminate all the ageing symptoms of the legacy database. The new database can therefore be readily used to integrate data used by new functions introduced in the legacy software. Moreover, the approach allows all the services offered by modern database management systems to be exploited. To test the effectiveness of the process described in this paper, it was experimented on a real legacy system; the results reported confirm its effectiveness.