Amador Durán

Automated error analysis for the agilization of feature modeling

Software Product Lines (SPL) and agile methods share the common goal of rapidly developing high-quality software. Although they follow different approaches to achieve it, some synergies can be found between them by (i) applying agile techniques to SPL activities so SPL development becomes more agile; and (ii) tailoring agile methodologies to support the development of SPL. Both options require an intensive use of feature models, which are usually strongly affected by changes on requirements. Changing large-scale feature models as a consequence of changes on requirements is a well-known error-prone activity. Since one of the objectives of agile methods is a rapid response to changes in requirements, it is essential an automated error analysis support in order to make SPL development more agile and to produce error-free feature models. As a contribution to find the intended synergies, this article sets the basis to provide an automated support to feature model error analysis by means of a framework which is organized in three levels: a feature model level, where the problem of error treatment is described; a diagnosis level, where an abstract solution that relies on Reiters theory of diagnosis is proposed; and an implementation level, where the abstract solution is implemented by using Constraint Satisfaction Problems (CSP). To show an application of our proposal, a real case study is presented where the Feature-Driven Development (FDD) methodology is adapted to develop an SPL. Current proposals on error analysis are also studied and a comparison among them and our proposal is provided. Lastly, the support of new kinds of errors and different implementation levels for the proposed framework are proposed as the focus of our future work.

Supporting requirements verification using XSLT

We present a light-weight approach for the automatic verification of requirements. This approach is not based on natural language parsing techniques but on the representation of requirements in XML. In our approach, XSLT stylesheets are used not only to automatically generate requirements documents, but also to provide verification-oriented heuristics as well as to measure the quality of requirements using some verification-oriented metrics. These ideas have been implemented in REM, an experimental XML-based requirements management tool also described.

A Quality-Aware Approach to Web Services Procurement

Web services bring programmers a new way to develop advanced applications able to integrate any group of services on the Internet into a single solution. Web services procurement (WSP) is focussed on the acquisition of web services, including some complex tasks such as the specification of demands, the search for available offers, and the best choice selection. Although the technology to support them already exists, there are only a few approaches wherein quality-of-service in demands and offers is taken into account, in addition to functionality. In this paper, we present some implementation issues on a quality-aware approach to WSP, whose solution is mainly based on using mathematical constraints to define quality-of-service in demands and offers.

Automated support for quality requirements in Web-service-based systems

The automatic checking of quality requirements will play a fundamental role in the future market of Web services. The reason is that it will allow one to build economically-optimal systems whose quality level can be guaranteed. We identify some of the main problems with which this kind of future system is going to be faced, and also make a realistic proposal to solve them. The key point is to view quality requirements from a twofold perspective: a natural language sentence and a constraint on a quality attribute. Thanks to this principle, some of the classical disadvantages of formal methods may be overcome.

Using templates and linguistic patterns to define process performance indicators

Process performance management (PPM) aims at measuring, monitoring and analysing the performance of business processes (BPs), in order to check the achievement of strategic and operational goals and to support decision-making for their optimisation. PPM is based on process performance indicators (PPIs), so having an appropriate definition of them is crucial. One of the main problems of PPIs definition is to express them in an unambiguous, complete, understandable, traceable and verifiable manner. In practice, PPIs are defined informally – usually in ad hoc, natural language, with its well-known problems – or they are defined from an implementation perspective, hardly understandable to non-technical people. In order to solve this problem, in this article we propose a novel approach to improve the definition of PPIs using templates and linguistic patterns. This approach promotes reuse, reduces both ambiguities and missing information, is understandable to all stakeholders and maintains traceability with the process model. Furthermore, it enables the automated processing of PPI definitions by its straightforward translation into the PPINOT metamodel, allowing the gathering of the required information for their computation as well as the analysis of the relationships between them and with BP elements.

Automating the Procurement of Web Services

As government agencies and business become more dependent on web services, software solutions to automate their procurement gain importance. Current approaches for automating the procurement of web services suffer from an important drawback: neither uncertainty measures nor non-linear, and complex relations among parameters can be used by providers to specify quality-of-service in offers. In this paper, we look deeply into the roots of this drawback and present a proposal which overcomes it. The key point to achieve this improvement has been using the constraint programming as a formal basis, since it endows the model with a very powerful expressiveness. A XML-based implementation is presented along with some experimental results and comparisons with other approaches.

Modelling Service Level Agreements for Business Process Outsourcing Services

Many proposals to model service level agreements (SLAs) have been elaborated in order to automate different stages of the service lifecycle such as monitoring, implementation or deployment. All of them have been designed for computational services and are not well–suited for other types of services such as business process outsourcing (BPO) services. However, BPO services supported by process–aware information systems could also benefit from modelling SLAs in tasks such as performance monitoring, human resource assignment or process configuration. In this paper, we identify the requirements for modelling such SLAs and detail how they can be faced by combining techniques used to model computational SLAs, business processes, and process performance indicators. Furthermore, our approach has been validated through the modelling of several real BPO SLAs.

Automated metamorphic testing of variability analysis tools

Variability determines the capability of software applications to be configured and customized. A common need during the development of variability‐intensive systems is the automated analysis of their underlying variability models, for example, detecting contradictory configuration options. The analysis operations that are performed on variability models are often very complex, which hinders the testing of the corresponding analysis tools and makes difficult, often infeasible, to determine the correctness of their outputs, that is, the well‐known oracle problem in software testing. In this article, we present a generic approach for the automated detection of faults in variability analysis tools overcoming the oracle problem. Our work enables the generation of random variability models together with the exact set of valid configurations represented by these models. These test data are generated from scratch using stepwise transformations and assuring that certain constraints (a.k.a. metamorphic relations) hold at each step. To show the feasibility and generalizability of our approach, it has been used to automatically test several analysis tools in three variability domains: feature models, common upgradeability description format documents and Boolean formulas. Among other results, we detected 19 real bugs in 7 out of the 15 tools under test. Copyright

Verifying software requirements with XSLT

In this article, we present an approach for the automatic verification of software requirements documents. This approach is based on the representation of software requirements in XML and the usage of the XSLT language not only to automatically generate requirements documents, but also to verify some desired quality properties and to compute some metrics. These ideas have been implemented in REM, an experimental requirements management tool that is also described in this paper.

Empirically Driven Use Case Metamodel Evolution

Metamodel evolution is rarely driven by empirical evidences of metamodel drawbacks. In this paper, the evolution of the use case metamodel used by the publicly available requirements management tool REM is presented. This evolution has been driven by the analysis of empirical data obtained during the assessment of several metrics–based verification heuristics for use cases developed by some of the authors and previously presented in other international fora. The empirical analysis has made evident that some common defects found in use cases developed by software engineering students were caused not only by their lack of experience but also by the expressive limitations imposed by the underlying use case metamodel used in REM. Once these limitations were clearly identified, a number of evolutionary changes were proposed to the REM use case metamodel in order to increase use case quality, i.e. to avoid those situations in which the metamodel were the cause of defects in use case specifications.