Miguel Toro

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.

Evolutionary learning of hierarchical decision rules

This paper describes an approach based on evolutionary algorithms, hierarchical decision rules (HIDER), for learning rules in continuous and discrete domains. The algorithm produces a hierarchical set of rules, that is, the rules are sequentially obtained and must therefore be tried until one is found whose conditions are satisfied. Thus, the number of rules may be reduced because the rules could be inside of one another. The evolutionary algorithm uses both real and binary coding for the individuals of the population. We tested our system on real data from the UCI repository, and the results of a ten-fold cross-validation are compared to C4.5s, C4.5Rules, See5s, and See5Rules. The experiments show that HIDER works well in practice.

An evolutionary approach to estimating software development projects

Abstract The use of dynamic models and simulation environments in connection with software projects paved the way for tools that allow us to simulate the behaviour of the projects. The main advantage of a Software Project Simulator (SPS) is the possibility of experimenting with different decisions to be taken at no cost. In this paper, we present a new approach based on the combination of an SPS and Evolutionary Computation. The purpose is to provide accurate decision rules in order to help the project manager to take decisions at any time in the development. The SPS generates a database from the software project, which is provided as input to the evolutionary algorithm for producing the set of management rules. These rules will help the project manager to keep the project within the cost, quality and duration targets. The set of alternatives within the decision-making framework is therefore reduced to a quality set of decisions.

IMPROVING THE AUTOMATIC PROCUREMENT OF WEB SERVICES USING CONSTRAINT PROGRAMMING

Software solutions to automate the procurement of web services are gaining importance when technology evolves, the number of providers increases and the needs of the clients become more complex. There are several proposals in this field, but they all have important drawbacks, namely: many of them are not able to check offers and demands for internal consistency; selecting the best offer usually relies on evaluating linear objective functions, which is quite a naive solution; the language to express offers is usually less expressive than the language to express demands; and, last but not least, providers cannot impose constraints on their clients. In this article, we present a solution to overcome these problems that relies on constraint programming; furthermore, we present a run-time framework, some experimental results, and a comparison with other proposals.

Finding representative patterns with ordered projections

This paper presents a new approach to 2nding representative patterns for dataset editing. The algorithm patterns by ordered projections (POP), has some interesting characteristics: important reduction of the number of instances from the dataset; lower computational cost (� (mn log n)) with respect to other typical algorithms due to the absence of distance calculations; conservation of the decision boundaries, especially from the point of view of the application of axis-parallel classi2ers. POP works well in practice withbothcontinuous and discrete attributes. The performance of POP is analysed in two ways: percentage of reduction and classi2cation. POP has been compared to IB2, ENN and SHRINK concerning the percentage of reduction and the computational cost. In addition, we have analysed the accuracy of k-NN and C4.5 after applying the reduction techniques. An extensive empirical study using datasets with continuous and discrete attributes from the UCI repository shows that POP is a valuable preprocessing method for the later application of any axis-parallel learning algorithm. ? 2002 Pattern Recognition Society. Published by Elsevier Science Ltd. All rights reserved.

An order‐based algorithm for implementing multiparty synchronization

Multiparty interactions are a powerful mechanism for coordinating several entities that need to cooperate in order to achieve a common goal. In this paper, we present an algorithm for implementing them that improves on previous results in that it does not require the whole set of entities or interactions to be known at compile‐ or run‐time, and it can deal with both terminating and non‐terminating systems. We also present a comprehensive simulation analysis that shows how sensitive to changes our algorithm is, and compare the results with well‐known proposals by other authors. This study proves that our algorithm still performs comparably to other proposals in which the set of entities and interactions is known beforehand, but outperforms them in some situations that are clearly identified. In addition, these results prove that our algorithm can be combined with a technique called synchrony loosening without having an effect on efficiency. Copyright

A simplified model of software project dynamics

Abstract The simulation of a dynamic model for software development projects (hereinafter SDPs) helps to investigate the impact of a technological change, of different management policies, and of maturity level of organisations over the whole project. In the beginning of the 1990s, with the appearance of the dynamic model for SDPs by Abdel-Hamid and Madnick [Software Project Dynamics: An Integrated Approach, Prentice-Hall, Englewood Cliffs, NJ, 1991], a significant advance took place in the field of project management. From this work, several dynamic models have been developed in order to simulate the behaviour of these kinds of projects. From the comparison made between one of the best known empirical estimation models and dynamic estimation models, we have analysed the existing problems in dynamic models in order to make dynamic estimations at the early stages of software projects, when little information is available. We present the results obtained from a Reduced Dynamic Model developed to estimate and analyse the behaviour of SDPs in the early phases, in which there is not much information regarding the project. The modelling approach followed to obtain this simplified model has been determined by the simplification of Abdel-Hamid and Madnicks model using the works of Eberlein [Syst. Dyn. Rev. 1(5) (1989) 51] about understanding and simplification of models.

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.

Implementing multiparty interactions on a network computer

Classical client/server interaction primitives such as remote procedure call or rendez-vous are not adequate when we need to describe the behaviour of three or more processes that need to collaborate simultaneously in order to solve a problem. Multiparty interactions are the key to describe these problems, and there are several languages that use them for the description of reactive systems. In this paper, we show and compare two different fair implementations of this mechanism and also outline the research we are carrying out in an effort to improve them.