A Framework for the Evaluation of Semantics-based Service Composition Approaches

The benefits of service composition are being largely acknowledged in the literature nowadays. However, as the amount of available services increases, it becomes difficult to manage, discover, select and compose them, so that automation is required in these processes. This can be achieved by using semantic information represented in ontologies. Currently there are many different approaches that support semantics-based service composition. However, still little effort has been spent on creating a common methodology to evaluate and compare such approaches. In this paper we present our initial ideas to create an evaluation framework for semantics-based service composition approaches. We use a collection of existing services, and define a set of evaluation metrics, confusion matrix-based and time-based. Furthermore, we present how composition evaluation scenarios are generated from the collection of services and specify the strategy to be used in the evaluation process. We demonstrate the proposed framework through an example. Currently there are mechanisms and initiatives to address the evaluation of the semantics-based service discovery and matchmaking approaches. However, still few efforts have been spent on the creation of comprehensive evaluation mechanisms for semantics-based service composition approaches

Tree structure data change detection method

The new method, increasing efficiency and reliability of change detection in three structures in the Internet data under indetermination of data structure (DTD, XML-Schema) is proposed in this paper. The Boolean linear programming problem was solved in two exact methods – modified Balazs with filter and modified DP method and A modified method for selecting a neural network architecture was proposed. There is also considered publish/subscribe system description enhanced with core module, which provides notifications of changes to subscribers only in case they occurred

Підходи до семантичного пошуку веб-сервісів в глобальному середовищі

Олексенко О. О. Підходи до семантичного пошуку веб-сервісів в глобальному середовищі / О. О. Олексенко, Л. С. Глоба // Інформатика та системні науки (ІСН-2015): матеріали VI Всеукраїнської науково-практичної конференції за міжнародною участю, (м. Полтава, 19–21 берез. 2015 р.). – Полтава: ПУЕТ, 2015

Підходи до семантичного пошуку веб-сервісів в глобальному середовищі

Олексенко О. О. Підходи до семантичного пошуку веб-сервісів в глобальному середовищі / О. О. Олексенко, Л. С. Глоба // Інформатика та системні науки (ІСН-2015): матеріали VI Всеукраїнської науково-практичної конференції за міжнародною участю, (м. Полтава, 19–21 берез. 2015 р.). – Полтава: ПУЕТ, 2015

Be4SeD: Benchmarking para evaluación de técnicas de descubrimiento de servicios

Actualmente, el creciente número de procesos de negocio y servicios ofrecidos, es fuente de innumerables proyectos de investigación, orientados a generar mecanismos de descubrimiento; teniendo como resultado un sinnúmero de algoritmos para recuperar servicios. Sin embargo, dichos proyectos no utilizan una base común para evaluar sus técnicas de búsqueda, impidiendo que las evaluaciones sean objetivas. Por lo tanto, se hace necesaria una herramienta pública, que proporcione una referencia común, que permita comparar y valorar los resultados de los diferentes algoritmos utilizados en el emparejamiento de servicios, con el fin de mejorar la calidad de las técnicas de descubrimiento propuestas. Este artículo presenta una aplicación pública, que implementa una metodología de benchmarking para evaluar la calidad de recuperación de las técnicas de emparejamiento de servicios. Este benchmarking está compuesto de un mecanismo de evaluación intuitivo, de un módulo de ingreso de los datos correspondientes al algoritmo a evaluar y un componente que entrega resultados estadísticos: recall, precision, overall, k-precision y p-precision. Sus funcionalidades se ofrecen como servicio web para facilitar la integración con las implementaciones de algoritmos a evaluar. Finalmente se evalúa un algoritmo de emparejamiento, el cual evidencia el uso de la plataforma Be4SeD en este contexto

Enhanced matching engine for improving the performance of semantic web service discovery

Web services are the means to realize the Service Oriented Architecture (SOA) paradigm. One of the key tasks of the Web services is discovery also known as matchmaking. This is the act of locating suitable Web services to fulfill a specific goal and adding semantic descriptions to the Web services is the key to enabling an automated, intelligent discovery process. Current Semantic Web service discovery approaches are primarily classified into logic-based, non-logic-based and hybrid categories. An important challenge yet to be addressed by the current approaches is the use of the available constructs in Web service descriptions to achieve a better performance in matchmaking. Performance is defined in terms of precision and recall as well-known metrics in the information retrieval field. Moreover, when matchmaking a large number of Web services, maintaining a reasonable execution time becomes a crucial challenge. In this research, to address these challenges, a matching engine is proposed. The engine comprises a new logic-based and nonlogic- based matchmaker to improve the performance of Semantic Web service discovery. The proposed logic-based and non-logic-based matchmakers are also combined as a hybrid matchmaker for further improvement of performance. In addition, a pre-matching filter is used in the matching engine to enhance the execution time of matchmaking. The components of the matching engine were developed as prototypes and evaluated by benchmarking the results against data from the standard repository of Web services. The comparative evaluations in terms of performance and execution time highlighted the superiority of the proposed matching engine over the existing and prominent matchmakers. The proposed matching engine has been proven to enhance both the performance and execution time of the Semantic Web service discovery

Enhancement of the usability of SOA services for novice users

Recently, the automation of service integration has provided a significant advantage in delivering services to novice users. This art of integrating various services is known as Service Composition and its main purpose is to simplify the development process for web applications and facilitates reuse of services. It is one of the paradigms that enables services to end-users (i.e.service provisioning) through the outsourcing of web contents and it requires users to share and reuse services in more collaborative ways. Most service composers are effective at enabling integration of web contents, but they do not enable universal access across different groups of users. This is because, the currently existing content aggregators require complex interactions in order to create web applications (e.g., Web Service Business Process Execution Language (WS-BPEL)) as a result not all users are able to use such web tools. This trend demands changes in the web tools that end-users use to gain and share information, hence this research uses Mashups as a service composition technique to allow novice users to integrate publicly available Service Oriented Architecture (SOA) services, where there is a minimal active web application development. Mashups being the platforms that integrate disparate web Application Programming Interfaces (APIs) to create user defined web applications; presents a great opportunity for service provisioning. However, their usability for novice users remains invalidated since Mashup tools are not easy to use they require basic programming skills which makes the process of designing and creating Mashups difficult. This is because Mashup tools access heterogeneous web contents using public web APIs and the process of integrating them become complex since web APIs are tailored by different vendors. Moreover, the design of Mashup editors is unnecessary complex; as a result, users do not know where to start when creating Mashups. This research address the gap between Mashup tools and usability by the designing and implementing a semantically enriched Mashup tool to discover, annotate and compose APIs to improve the utilization of SOA services by novice users. The researchers conducted an analysis of the already existing Mashup tools to identify challenges and weaknesses experienced by novice Mashup users. The findings from the requirement analysis formulated the system usability requirements that informed the design and implementation of the proposed Mashup tool. The proposed architecture addressed three layers: composition, annotation and discovery. The researchers developed a simple Mashup tool referred to as soa-Services Provisioner (SerPro) that allowed novice users to create web application flexibly. Its usability and effectiveness was validated. The proposed Mashup tool enhanced the usability of SOA services, since data analysis and results showed that it was usable to novice users by scoring a System Usability Scale (SUS) score of 72.08. Furthermore, this research discusses the research limitations and future work for further improvements

Personalised service discovery in mobile environments

In recent years, some trends have emerged that pertain both to mobile devices and the Web. On one side, mobile devices have transitioned from being simple wireless phones to become ubiquitous Web-enabled users' companions. On the other side, the Web has evolved from an online one-size-fits-all collection of interlinked documents to become an open platform of personalised services and content. It will not be long before these trends will converge and create a Seamless Web: an integrated environment where, besides traditional services delivered by powerful server machines accessible via wide area networks, new services and content will be offered by users to users via their portable devices. As a result, mobile users will soon be exposed - in addition to traditional "on-line" Web services/content - to a parallel universe of pervasive "off-line" services provided by devices in their surroundings. Such circumstances will raise new challenges when it comes to selecting the services to rely on, that will require solutions grounded on the characteristics of mobile environments. Two aspects will require particular attention: first, users will have access to a countless multitude of services impossible to explore; they will need assistance to identify, among this multitude, those services they are most likely to enjoy. Secondly, if today's services (and their providers) are always-on, `static' and aiming at Five 9s availability, tomorrow's pervasive services will be mobile (as devices move), fine-grained, increasingly composite (to provide richer functionalities) and so more unreliable by nature. Our research tackles the problem of service discovery in pervasive environments in two ways: on one hand, we support personalised discovery by means of a mobile recommender system, easing the discovery of pervasive services appealing to end-users. On the other hand, we enable reliable discovery, by reasoning on the composite nature of pervasive services and the physical availability of their component providers. Overall, we provide a discovery method that enables 'better' pervasive services, where by 'better' we mean both `more interesting' to the user and 'more reliable'

Découverte de services web via le cloud computing à base d’agent mobile

Avec la rapidité de l'évolution des services Cloud, en nombre comme en fonctionnalités, le besoin d'un moteur de découverte et de composition de services devient une nécessité incontournable. Afin de réaliser un tel système, nous devons faire recours aux technologies adaptées à la nature de ce type d'applications, à savoir, les technologies d'agents et cloud computing. La technologie d'agent est très adéquate pour la modélisation des systèmes qui nécessite une collaboration entre plusieurs entités, afin de réaliser un but commun, comme la réalisation d'un système où les agents collaborent pour trouver les meilleurs services web qui correspondent aux exigences fonctionnelles et non-fonctionnelles des clients. Outre, la nature distribuée des services Cloud nous impose l’utilisation d’agents mobiles afin de chercher et créer des pistes de communications sécurisées et à moindre coût entre le moteur de recherche et les fournisseurs de services web. La technologie cloud computing, représente un atout considérable pour les applications distribuées sur internet. D'un côté cette technologie permet aux clients de payer seulement ce qu'ils utilisent comme ressources virtuelles et logicielles et leurs évite d'acheter à chaque fois la nouvelle version du système qu'ils utilisent ; d'un autre côté, cette technologie permet d'avoir un support physique et virtuel avec des capacités de stockage et de traitement illimitées. Dans notre thèse on s’est à l’étude et la proposition d’un moteur de découverte et composition qui peut accueillir et traiter des milliers de requêtes et de fichiers WSDL en même temps, et avec les meilleurs temps de réponse. Dans cette thèse nous proposant une nouvelle architecture Cloud computing basée agents pour la découverte et composition des services SaaS. Cette architecture a pour but de supporter et d'exécuter un nouveau mécanisme de sélection, composition et classification de services, ce mécanisme est basé sur une nouvelle mesure, qu'on a appelé "le degré d'existence", cette mesure nous permet de calculer le degré d'adaptation de la requête par rapport aux représentations arborescente des fichiers WSDL. De plus, ce mécanisme combine les paramètres QoS et fonctionnels pour effectuer la composition de services SaaS, ce qui permet d'avoir des services composites qui répondent aux exigences fonctionnelles et non fonctionnelles des clients. Les résultats de la simulation montrent l'efficacité du moteur de découverte et composition de services SaaS notamment en temps de réponse. L'accent est mis sur la nécessité de développer un modèle économique qui s'adapte aux fonctionnements et techniques de ce genre de moteur. Enfin, nous avons proposé un modèle de comparaison et d’évaluation afin de pouvoir comparer l’approche proposée avec les autres approches du domaine

Evaluation of Semantic Service Discovery -- A Survey and Directions for Future Research

In recent years a huge amount of effort and money has been invested in the area of semantic service discovery and presented approaches have become more sophisticated and mature. Nevertheless surprisingly little effort is being put into the evaluation of these approaches. We argue that the lack of established and theoretically well-founded methodologies and test beds for comparative evaluation of semantic service discovery is a major blocker of the advancement of the field. To lay the ground for a comprehensive treatment of this problem we discuss the applicability of well-known evaluation methodologies from information retrieval and provide an exhaustive survey of the current evaluation approaches