WS-Governance: a Policy Language for SOA Governance

The widespread use of Service Oriented Architectures (SOA) is beginning to create problems derived from the governance of said structures. To date there is not a single effective solution to solve all existing challenges to govern this type of infrastructure. This paper describes the problems encountered when designing a SOA governance solution in a real e-Government scenario. More specifically, we focus on problems related to specification and automated analysis of government policies. We propose a novel SOA governance specification model as a solution to these problems. We have named this model WS-Governance. in order to ease its adoption by SOA practitioners it: i) shares WS-Policy guidelines and is compatible with it, ii) has XML serialization as well as a plain-text one and iii) has a CSP based semantics that provides a precise description as well as facilitating the automation of some editing and WS-Governance related activities such as consistency checking

Spectrum-Based Fault Localization in Model Transformations

Model transformations play a cornerstone role in Model-Driven Engineering (MDE), as they provide the essential mechanisms for manipulating and transforming models. The correctness of software built using MDE techniques greatly relies on the correctness of model transformations. However, it is challenging and error prone to debug them, and the situation gets more critical as the size and complexity of model transformations grow, where manual debugging is no longer possible. Spectrum-Based Fault Localization (SBFL) uses the results of test cases and their corresponding code coverage information to estimate the likelihood of each program component (e.g., statements) of being faulty. In this article we present an approach to apply SBFL for locating the faulty rules in model transformations. We evaluate the feasibility and accuracy of the approach by comparing the effectiveness of 18 different stateof- the-art SBFL techniques at locating faults in model transformations. Evaluation results revealed that the best techniques, namely Kulcynski2, Mountford, Ochiai, and Zoltar, lead the debugger to inspect a maximum of three rules to locate the bug in around 74% of the cases. Furthermore, we compare our approach with a static approach for fault localization in model transformations, observing a clear superiority of the proposed SBFL-based method.Comisión Interministerial de Ciencia y Tecnología TIN2015-70560-RJunta de Andalucía P12-TIC-186

Achieving Replicability: Is There Life for Our Experiments After Publication?

Metaheuristics are algorithmic schemes that ease the derivation of novel algorithms to solve optimization problems. These algorithms are typically approximated and stochastic, leading to the preeminence of experimentation as the mean of supporting claims in research and applications. However, the huge number of variants and parameters of most metaheuristics, the ambiguity of natural language used in papers, and the lack of widely accepted reporting standards threatens the replicability of those experiments. This problem, that has been identified in the literature by several authors, significantly hinders the construction of a complete and cohesive body of knowledge on the behavior of metaheuristics. This paper proposes a set of minimum information guidelines for reporting metaheuristic experiments, and an experiment description language that supports the meeting of those guidelines. By using this language, metaheuristic optimization experiments are described in a toolindependent and unambiguous way, while maintaining readability and succinctness. Those contributions pave the way for replication using different problem instances and parameters, bringing a new life to metaheuristic experiments after publication.Ministerio de Ciencia e Innovación TIN2009-07366Ministerio de Economía y Competitividad TIN2012-32273Junta de Andalucía P07-TIC-2533Junta de Andalucía TIC-590

SLAWS: Towards a Conceptual Architecture for SLA Enforcement

Current technologies in Service Oriented Computing (SOC) provide a solid framework to drive the interaction of organizations from a functional point of view. in order to introduce non-functional properties in this scenario, the concept of Service Level Agreement (SLAs) comes into play as a key element. SLAs can be seen as containers of the functional and non-functional properties that both parties (the service consumer and the service provider) agree specifying its rights and obligations during the interaction. However this SLAs represent an additional responsibility for the service provider since it motivates the need of a SLAEnforcement process in its infrastructure. A proper SLAenforcement implies optimized resource usage that meet SLAs established with consumer, making it possible to the provider afford a larger number of customers to maximize its benefits. Current approaches to SLA enforcement are domainspecific approaches and/or based on monolithic platforms (from a SOC point of view).In this paper we propose a conceptual architecture (SLAWs) for SLA enforcement. The main goal of the proposed architecture is to be used as a conceptual framework to build a flexible SLA enforcement layer. This layer could be integrated in a seamless way in the pre-existing provider infrastructure when is based upon the service oriented architecture principles

STATService: Herramienta de análisis estadístico como soporte para la investigación con Metaheurísticas

Actualmente, la aplicación de técnicas estadísticas es una necesidad cuando se trabaja con metaheurísticas. A pesar de que existen multitud de paquetes software para el cálculo estadístico, estos sistemas exigen en la mayoría de los casos la instalación de componentes y no son fáciles de integrar con otros sistemas. En este artículo presentamos un conjunto de herramientas para análisis estadístico denominado STATService, que puede usarse a través de un portal web. STATService provee además interfaces programáticas a través de servicios web que hacen que su integración con otros sistemas sea extremadamente simple, independientemente de la plataforma y tecnologías concretas de dichos sistemas

FAST-SE: An Esb Based Framework for SLA Trading

SLA driven service transaction has been identified as a key challenge to take advantage of a SOA. FAST System provides a software framework for the automated creation of SLAs. in particular it have been developed as an extension to the ESB (Enterprise Service Bus) paradigm to create a transparent SLA management layer that drives any service invocation. Our framework has been successfully applied in two different scenarios and provides an extensible architecture to address new domains

WS-Governance Tooling: SOA Governance Policies analysis and authoring

Governance is a capital issue in current Service Oriented Arcuitectures, and governance policies are at its base. The governance policies definition must be supported by proper languages and tools, allowing for comfortable and collaborative editing, consistency checking and the evaluation policy meeting. In this paper we present a policy analizer for WS-Governance (a governance policy definition language created by authors, described in [1]) together with an online editor and test suite with classical examples of WS-Governance Documents for consistency validation. Both the test model and the analysis tool prove the suitability of WS-Governance to define SOA governance policiesComisión Interministerial de Ciencia y Tecnología (CICYT) SETI (TIN2009-07366)Junta de Andalucía TIC-2533Junta de Andalucía TIC-590

QoS-Aware Semantic Service Selection: An Optimization Problem

In order to select the best suited service among a set of discovered services, with respect to QOS parameters, a user have to state his or her preferences, so services can be ranked according to these QOS parameters. Current Se- mantic Web Services ontologies do not support the defini- tion of QOS-aware user preferences, though there are some proposals that extend those ontologies to allow selection based on those preferences. However, their selection algo- rithms are very coupled with user preferences descriptions, which are defined without semantics or at a different seman- tic level than service functionality. In this work, we present a service selection framework that transforms user prefer- ences into an optimization problem where the best service is selected. This framework is based on an ontology that conceptualizes these user preferences. Thus, we use a very expressive solution decoupled with the concrete selection technique by using XSL transformations, while describing QOS-aware user preferences at the same semantic level of functional preferences.Comisión Interministerial de Ciencia y Tecnología TIN2006-00472Junta de Andalucía TIC-253

Metaheuristic Optimization Frameworks: a Survey and Benchmarking

This paper performs an unprecedented comparative study of Metaheuristic optimization frameworks. As criteria for comparison a set of 271 features grouped in 30 characteristics and 6 areas has been selected. These features include the different metaheuristic techniques covered, mechanisms for solution encoding, constraint handling, neighborhood specification, hybridization, parallel and distributed computation, software engineering best practices, documentation and user interface, etc. A metric has been defined for each feature so that the scores obtained by a framework are averaged within each group of features, leading to a final average score for each framework. Out of 33 frameworks ten have been selected from the literature using well-defined filtering criteria, and the results of the comparison are analyzed with the aim of identifying improvement areas and gaps in specific frameworks and the whole set. Generally speaking, a significant lack of support has been found for hyper-heuristics, and parallel and distributed computing capabilities. It is also desirable to have a wider implementation of some Software Engineering best practices. Finally, a wider support for some metaheuristics and hybridization capabilities is needed