Jürgen Börstler

The PLUSS approach: domain modeling with features, use cases and use case realizations

This paper describes a product line use case modeling approach tailored towards organizations developing and maintaining extremely long lived software intensive systems. We refer to the approach as the PLUSS approach, Product Line Use case modeling for Systems and Software engineering . An industrial case study is presented where PLUSS is applied and evaluated in the target domain. Based on the case study data we draw the conclusion that PLUSS performs better than modeling according to the styles and guidelines specified by the IBM-Rational Unified Process (RUP) in the current industrial context.

Teaching PSP: challenges and lessons learned

Software engineering educators need to provide environments where students learn about the size and complexity of modern software systems and the techniques available for managing these difficulties. Five universities used the personal software process to teach software engineering concepts in a variety of contexts.

Empirical evidence on the link between object-oriented measures and external quality attributes: a systematic literature review

There is a plethora of studies investigating object-oriented measures and their link with external quality attributes, but usefulness of the measures may differ across empirical studies. This study aims to aggregate and identify useful object-oriented measures, specifically those obtainable from the source code of object-oriented systems that have gone through such empirical evaluation. By conducting a systematic literature review, 99 primary studies were identified and traced to four external quality attributes: reliability, maintainability, effectiveness and functionality. A vote-counting approach was used to investigate the link between object-oriented measures and the attributes, and to also assess the consistency of the relation reported across empirical studies. Most of the studies investigate links between object-oriented measures and proxies for reliability attributes, followed by proxies for maintainability. The least investigated attributes were: effectiveness and functionality. Measures from the C&K measurement suite were the most popular across studies. Vote-counting results suggest that complexity, cohesion, size and coupling measures have a better link with reliability and maintainability than inheritance measures. However, inheritance measures should not be overlooked during quality assessment initiatives; their link with reliability and maintainability could be context dependent. There were too few studies traced to effectiveness and functionality attributes; thus a meaningful vote-counting analysis could not be conducted for these attributes. Thus, there is a need for diversification of quality attributes investigated in empirical studies. This would help with identifying useful measures during quality assessment initiatives, and not just for reliability and maintainability aspects.

Managing requirements specifications for product lines - An approach and industry case study

Software product line development has emerged as a leading approach for software reuse. This paper describes an approach to manage natural-language requirements specifications in a software product line context. Variability in such product line specifications is modeled and managed using a feature model. The proposed approach has been introduced in the Swedish defense industry. We present a multiple-case study covering two different product lines with in total eight product instances. These were compared to experiences from previous projects in the organization employing clone-and-own reuse. We conclude that the proposed product line approach performs better than clone-and-own reuse of requirements specifications in this particular industrial context.

A controlled empirical evaluation of a requirements abstraction model

Requirement engineers in industry are faced with the complexity of handling large amounts of requirements as development moves from traditional bespoke projects towards market-driven development. There is a need for usable and useful models that recognize this reality and support the engineers in a continuous effort of choosing which requirements to accept and which to dismiss off hand using the goals and product strategies put forward by management. This paper presents an evaluation of such a model that is built based on needs identified in industry. The evaluations primary goal is to test the models usability and usefulness in a lab environment prior to large scale industry piloting, and is a part of a large technology transfer effort. The evaluation uses 179 subjects from three different Swedish Universities, which is a large portion of the university students educated in requirements engineering in Sweden during 2004 and 2005. The results provide a strong indication that the model is indeed both useful and usable and ready for industry trials.

An industrial case study on requirements volatility measures

Requirements volatility is an important risk factor for software projects. Software measures can help in quantifying and predicting this risk. In this paper, we present an industrial case study that investigated measures of volatility for a medium size software project. The goal of the study was twofold: 1) to empirically validate a set of measures associated with the volatility of use case models (UCM); 2) to investigate the correlation between subjective and objective volatility. Measurement data was collected in retrospect for all use case models of the software project. In addition, we determined subjective volatility by interviewing stakeholders of the project. Our data analysis showed a high correlation between our measures of size of UCM and total number of changes, indicating that the measures of size of UCMs are good indicators of requirements volatility. No correlations was found between subjective and objective volatility. These results suggest that project managers at this company should measure their projects because of the risk to take wrong decisions based on their own and the developers perceptions.

Software product line modeling made practical

An example from the Swedish Defense Industry.

The PLUSS toolkit?: extending telelogic DOORS and IBM-rational rose to support product line use case modeling

The PLUSS approach (Product Line Use case modeling for Systems and Software engineering) is a domain modeling method tailored towards the development of long lived software intensive systems. PLUSS provides means to maintain a common and complete use case model for a whole family of systems. In this paper, we describe how the commercial requirements management tool Telelogic DOORS and the UML modeling tool IBM-Rational Rose can be extended and used for managing system family models in accordance with the PLUSS approach.

Client sponsored projects in software engineering courses

A growing trend in Software Engineering (SE) courses, especially in capstones, is to use an actual business or industry client for case-based projects. We will broadly examine approaches taken to deal with situations occurring when projects with outside clients are brought into the classroom at various size institutions in different countries. Specifically we will discuss the issues of client management, team management, project assessment, and preparation and planning for courses utilizing external clients.

On the Quality of Examples in Introductory Java Textbooks

Example programs play an important role in the teaching and learning of programming. Students as well as teachers rank examples as the most important resources for learning to program. Example programs work as role models and must therefore always be consistent with the principles and rules we are teaching. However, it is difficult to find or develop examples that are fully faithful to all principles and guidelines of the object-oriented paradigm and also follow general pedagogical principles and practices. Unless students are able to engage with good examples, they will not be able to tell desirable from undesirable properties in their own and others’ programs. In this article we report on a study in which experienced educators evaluated the quality of object-oriented example programs for novices from popular Java textbooks. The evaluation was accomplished using an online checklist that elicited responses on the technical, object-oriented, and didactic quality of examples. In total 25 reviewers contributed 215 reviews to our dataset, based on 38 example programs from 13 common introductory programming textbooks. Results show that the evaluation instrument is reliable in terms of inter-rater agreement. Overall, example quality was not as good as one might expect from common textbooks, in particular regarding certain object-oriented properties. We conclude that educators should be careful when taking examples straight out of a textbook.