Automated generation of computationally hard feature models using evolutionary algorithms

This is the post-print version of the final paper published in Expert Systems with Applications. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2014 Elsevier B.V.A feature model is a compact representation of the products of a software product line. The automated extraction of information from feature models is a thriving topic involving numerous analysis operations, techniques and tools. Performance evaluations in this domain mainly rely on the use of random feature models. However, these only provide a rough idea of the behaviour of the tools with average problems and are not sufficient to reveal their real strengths and weaknesses. In this article, we propose to model the problem of finding computationally hard feature models as an optimization problem and we solve it using a novel evolutionary algorithm for optimized feature models (ETHOM). Given a tool and an analysis operation, ETHOM generates input models of a predefined size maximizing aspects such as the execution time or the memory consumption of the tool when performing the operation over the model. This allows users and developers to know the performance of tools in pessimistic cases providing a better idea of their real power and revealing performance bugs. Experiments using ETHOM on a number of analyses and tools have successfully identified models producing much longer executions times and higher memory consumption than those obtained with random models of identical or even larger size.European Commission (FEDER), the Spanish Government and the Andalusian Government

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 qualityof- 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.Ministerio de Ciencia y Tecnología TIC2000-1106-C02-01Ministerio de Ciencia y Tecnología FIT-150100-2001-78Junta de Comunidades de Castilla La Mancha PCB-02-00

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-ofservice 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.Comisión Interministerial de Ciencia y Tecnología TIC 2000–1106–C02–01Ministerio de Ciencia y Tecnología TIC2003-02737-C02-01Ministerio de Ciencia y Tecnología FIT-150100-2001-7

Building and implementing policies in autonomous and autonomic systems using MaCMAS

Autonomic Computing, self-management based on high level guidance from humans, is increasingly being accepted as a means forward in designing reliable systems that both hide complexity from the user and control IT management costs. Effectively, AC may be viewed as Policy-Based Self-Management.We look at ways of achieving this, and in particular focus on Agent-Oriented Software Engineering. We propose utilizing MaCMAS, an AOSE methodology, for specifying autonomic and autonomous properties of the system independently, and later, by means of composition of these specifications, guided by a policy specification, construct a specification for the policy and its subsequent deployment. We illustrate this by means of a case study based on a NASA concept mission, and describe future work on a support toolkit

A Conceptual Framework for Efficient Web Crawling in Virtual Integration Contexts

Virtual Integration systems require a crawling tool able to navigate and reach relevant pages in the Web in an efficient way. Existing proposals in the crawling area are aware of the efficiency problem, but still most of them need to download pages in order to classify them as relevant or not. In this paper, we present a conceptual framework for designing crawlers supported by a web page classifier that relies solely on URLs to determine page relevance. Such a crawler is able to choose in each step only the URLs that lead to relevant pages, and therefore reduces the number of unnecessary pages downloaded, optimising bandwidth and making it efficient and suitable for virtual integration systems. Our preliminary experiments show that such a classifier is able to distinguish between links leading to different kinds of pages, without previous intervention from the user.Ministerio de Educación y Ciencia TIN2007-64119Junta de Andalucía P07-TIC-2602Junta de Andalucía P08- TIC-4100Ministerio de Ciencia e Innovación TIN2008-04718-EMinisterio de Ciencia e Innovación TIN2010-21744Ministerio de Economía, Industria y Competitividad TIN2010-09809-EMinisterio de Ciencia e Innovación TIN2010-10811-EMinisterio de Ciencia e Innovación TIN2010-09988-

Tool Supported Error Detection and Explanations on Feature Models

Automated analysis of feature models (FM) is a field of interest in recent years. Many operations over FMs have been proposed and developed, and many researchers and industrial companies have adopted FMs as a way to express variability. This last makes more necessary having support to detect, explain and fix errors on FMs. The notation of FMs makes very easy to express variability, but makes hard detecting errors and find their cause manually. and these errors may cause the model does not express the variability what we want of it. Therefore, we need support to detect errors and find their causes. The contribution of this paper is a method to detect errors in FMs, based on the concept of observation. We also present implementations of this approach and of an approach to explain errors, in FaMa Framework [1] tool. To detect FM errors, firstly we have to identify the different error types and what it means each of them. Void FM error means that the FM does not represent any product, dead feature error means that a feature of the FM does not appear in any product, false optional error means that an optional feature appears in every product that its parent feature also appears, and wrong cardinality error means that one or more values of a set relationship cardinality are not reachable. We can check for these errors in a intuitive way. For instance, to detect if a FM has dead features, we can calculate every product and check if each feature appears in, at least, one product. But further, we propose a method based on observations, it means, FM configurations associated with a specific element (feature or cardinality). Each type of error has its type of observation associated too. With an algorithm, we calculate the set of observations of a FM. Then, for each observation, we check if FM has at least one product. If not, we have found an error. For instance, dead feature observation sets its feature as selected. If the FM with a dead feature observation is not valid, it means the feature we are checking is dead. When we have found the errors, explanations tell us what is the cause of each error. An explanation is a set of relationships that originates one or more errors. Changing or removing these relationships we can fix a error. However, explanations by themselves do not provide information about how to change the relationship. For instance, if an explanation about a dead feature is a mandatory relationship, we can turn it into a optional relationship, but the explanation does not tell us directly. We have implemented observations and explanations approaches in FaMa Framework, a tool for the automated analysis of FMs. The observations approach implemented is the previously mentioned, while the explanations approach implemented is the one described by Trinidad et al. [3] [4]. With these approaches, we have detected errors in SPLOT FM repository [2], and we have obtained explanations for them also

A Tool for Web Links Prototyping

Crawlers for Virtual Integration processes must be efficient, given that VI process is online, which means that while the system is looking for the required information, the user is waiting for a response. Therefore, downloading a minimum number of irrelevant pages is mandatory in order to improve the crawler efficiency. Most crawlers need to download a page in order the determine its relevance, which results in a high number of irrelevant pages downloaded. We propose a tool that builds a set of prototype links for a given site, where each prototype represents links leading to pages containing a certain concept. These prototypes can then be used to classify pages before downloading them, just by analysing their URL. Therefore, they are the support for crawlers to navigate through sites downloading a minimum number of irrelevant pages while reducing bandwidth, making them suitable for VI systems.Ministerio de Educación y Ciencia TIN2007-64119Junta de Andalucía P07-TIC-2602Junta de Andalucía P08-TIC-4100Ministerio de Ciencia e Innovación TIN2008-04718-EMinisterio de Ciencia e Innovación TIN2010-21744Ministerio de Ciencia e Innovación TIN2010-09809-EMinisterio de Ciencia e Innovación TIN2010-10811-EMinisterio de Ciencia e Innovación TIN2010-09988-

Primeros datos polínicos de la secuencia "fuentillejo-1" de la laguna del Maar de Fuentillejo (Campo de Calatrava, Ciudad Real)

XV lnternational A.P.L.E. Symposium of Palynolog

A First Approach to Build Product Lines of Multi-organizationalWeb Based Systems (MOWS)

From the recent past and current state of the Internet, it is possible to forecast a wide growing of Multi Organizational Web–based Systems (MOWS). Therefore, the reduction of both costs and time–to–market is desirable. On the other hand, the success of building software in Product Lines (PL) is being demonstrated in different contexts reducing both time–to–market and costs. However, research on PL topics has not been oriented to include web–based assets. In this article, we propose a first approach to use PL methodologies to build MOWS.We identify quality aspects as a key point when building Product Lines of MOWS and we give a way to specify quality aspects in PL.Ministerio de Ciencia y Tecnología TIC 2003-02737-C02-0