261 research outputs found
A Review on Framework and Quality of Service Based Web Services Discovery
Selection of Web services (WSs) is one of the most important steps in the application of different types of WSs such as WS composition systems and the Universal
Description, Discovery, and Integration (UDDI) registries. The more available these WSs
on the Internet are, the wider the number of these services whose functions match the various service requests is. Selecting WSs with higher quality largely depends on the quality of service (QoS) since it plays a significant role in selecting such services. In
achieving this selection of the best WSs, the potential WSs are ranked according to the user’s necessities on service quality. In many cases, the value of QoS ontology is realized by its support for nonfunctional features of WSs. This ontology is also capable of providing
solutions to the interoperability of QoS description. Moreover, based on the QoS ontology,
it becomes more possible to develop a framework of semantic WS discovery. The framework enhances the automatic discovery of WSs and can improve the users’ efficiency in finding the best web services. Thus, Web Services are software functionalities publish
and accessible through the Internet. Different protocols and web mechanism have been defined to access these Services
Fruit fly optimization algorithm for network-aware web service composition in the cloud
Service Oriented Computing (SOC) provides a framework for the realization of loosely coupled service oriented applications. Web services are central to the concept of SOC. Currently, research into how web services can be composed to yield QoS optimal composite service has gathered significant attention. However, the number and spread of web services across the cloud data centers has increased, thereby increasing the impact of the network on composite service performance experienced by the user. Recently, QoS-based web service composition techniques focus on optimizing web service QoS attributes such as cost, response time, execution time, etc. In doing so, existing approaches do not separate QoS of the network from web service QoS during service composition. In this paper, we propose a network-aware service composition approach which separates QoS of the network from QoS of web services in the Cloud. Consequently, our approach searches for composite services that are not only QoS-optimal but also have optimal QoS of the network. Our approach consists of a network model which estimates the QoS of the network in the form of network latency between services on the cloud. It also consists of a service composition technique based on fruit fly optimization algorithm which leverages the network model to search for low latency compositions without compromising service QoS levels. The approach is discussed and the results of evaluation are presented. The results indicate that the proposed approach is competitive in finding QoS optimal and low latency solutions when compared to recent techniques
A graph-based framework for optimal semantic web service composition
Web services are self-described, loosely coupled software components that are network-accessible
through standardized web protocols, whose characteristics are described in XML. One of the key
promises of Web services is to provide better interoperability and to enable a faster integration
between systems. In order to generate robust service oriented architectures, automatic composition
algorithms are required in order to combine the functionality of many single services into composite
services that are able to respond to demanding user requests, even when there is no single service
capable of performing such task. Service composition consists of a combination of single services
into composite services that are executed in sequence or in a different order, imposed by a set of
control constructions that can be specified using standard languages such as OWL-s or BPEL4WS.
In the last years several papers have dealt with composition of web services. Some approaches treat
the service composition as a planning problem, where a sequence of actions lead from a initial state
to a goal state. However, most of these proposals have some drawbacks: high complexity, high
computational cost and inability to maximize the parallel execution of web services. Other
approaches consider the problem as a graph search problem, where search algorithms are applied
over a web service dependency graph in order to find a solution for a particular request. These
proposals are simpler than their counterparts and also many can exploit the parallel execution of
web services. However, most of these approaches rely on very complex dependency graphs that
have not been optimized to remove data redundancy, which may negatively affect the overall
performance and scalability of these techniques in large service registries. Therefore, it is necessary
to identify, characterize and optimize the different tasks involved in the automatic service
composition process in order to develop better strategies to efficiently obtain optimal solutions. The
main goal of this dissertation is to develop a graph-based framework for automatic service
composition that generate optimal input-output based compositions not only in terms of complexity
of the solutions, but also in terms of overall quality of service solutions. More specifically, the
objectives of this thesis are: (1) Analysis of the characteristics of services and compositions. The
aim of this objective is to characterize and identify the main steps that are part for the service
composition process. (2) Framework for automatic graph-based composition. This objective will
focus on developing a framework that enables the efficient input-output based service composition,
exploring the integration with other tasks that are part of the composition process, such as service
discovery. (3) Development of optimal algorithms for automatic service composition. This objective
focuses on the development of a set of algorithms and optimization techniques for the generation of
optimal compositions, optimizing the complexity of the solutions and the overall Quality-of-
Service. (4) Validation of the algorithms with standard datasets so they can be compared with other
proposals
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Discovering Services during Service-Based System Design Using UML
Recently, there has been a proliferation of service-based systems, i.e., software systems that are composed of autonomous services but can also use software code. In order to support the development of these systems, it is necessary to have new methods, processes, and tools. In this paper, we describe a UML-based framework to assist with the development of service-based systems. The framework adopts an iterative process in which software services that can provide functional and nonfunctional characteristics of a system being developed are discovered, and the identified services are used to reformulate the design models of the system. The framework uses a query language to represent structural, behavioral, and quality characteristics of services to be identified, and a query processor to match the queries against service registries. The matching process is based on distance measurements between the queries and service specifications. A prototype tool has been implemented. The work has been evaluated in terms of recall, precision, and performance measurements
Semantic Web Services Provisioning
Semantic Web Services constitute an important research area, where vari ous underlying frameworks, such as WSMO and OWL-S, define Semantic Web
ontologies to describe Web services, so they can be automatically discovered,
composed, and invoked. Service discovery has been traditionally interpreted
as a functional filter in current Semantic Web Services frameworks, frequently
performed by Description Logics reasoners. However, semantic provisioning
has to be performed taking Quality-of-Service (QOS) into account, defining
user preferences that enable QOS-aware Semantic Web Service selection.
Nowadays, the research focus is actually on QOS-aware processes, so cur rent proposals are developing the field by providing QOS support to semantic
provisioning, especially in selection processes. These processes lead to opti mization problems, where the best service among a set of services has to be
selected, so Description Logics cannot be used in this context. Furthermore,
user preferences has to be semantically defined so they can be used within
selection processes.
There are several proposals that extend Semantic Web Services frameworks
allowing QOS-aware semantic provisioning. However, proposed selection
techniques are very coupled with their proposed extensions, most of them
being implemented ad hoc. Thus, there is a semantic gap between functional
descriptions (usually using WSMO or OWL-S) and user preferences, which are
specific for each proposal, using different ontologies or even non-semantic de scriptions, and depending on its corresponding ad hoc selection technique.
In this report, we give an overview of most important Semantic Web Ser vices frameworks, showing a comparison between them. Then, a thorough
analysis of state-of-the art proposals on QOS-aware semantic provisioning and
user preferences descriptions is presented, discussing about their applicabil ity, advantages, and defects. Results from this analysis motivate our research
work, which has been already materialized in two early contributions.Los servicios web semánticos constituyen un importante campo de inves tigación, en el cual distintos frameworks, como por ejemplo WSMO y OWL-S,
definen ontologĂas de la web semántica para describir servicios web, de for ma que estos puedan ser descubiertos, compuestos e invocados de manera
automática. El descubrimiento de servicios ha sido interpretado tradicional mente como un filtro funcional en los frameworks actuales de servicios web
semánticos, usando para ello razonadores de lógica descriptiva. Sin embargo,
las tareas de aprovisionamiento semántico deberĂan tener en cuenta la calidad
del servicio, definiendo para ello preferencias de usuario de manera que sea
posible realizar una selección de servicios web semánticos sensible a la cali dad.
Actualmente, el foco de la investigación está en procesos sensibles a la ca lidad, por lo que las propuestas actuales están trabajando en este campo intro duciendo el soporte adecuado a la calidad del servicio dentro del aprovisio namiento semántico, y principalmente en las tareas de selección. Estas tareas
desembocan en problemas de optimizaciĂłn, donde el mejor servicio de entre
un concjunto debe ser seleccionado, por lo que las lógicas descriptivas no pue den ser usadas en este contexto. Además, las preferencias de usuario deben ser
definidas semánticamente, de forma que puedan ser usadas en las tareas de
selecciĂłn.
Existen bastantes propuestas que extienden los frameworks de servicios
web semánticos para habilitar el aprovisionamiento sensible a la calidad. Sin
embargo, las técnicas de selección propuestas están altamente acopladas con
dichas extensiones, donde la mayorĂa de ellas implementan algoritmos ad hoc.
Por tanto, existe un salto semántico entre las descripciones funcionales (nor malmente usando WSMO o OWL-S) y las preferencias de usuario, las cuales
son definidas especĂficamente por cada propuesta, usando ontologĂas distin tas o incluso descripciones no semánticas que dependen de la correspondiente
técnica de selección ad hoc
Constructing distributed time-critical applications using cognitive enabled services
Time-critical analytics applications are increasingly making use of distributed service interfaces (e.g., micro-services) that support the rapid construction of new applications by dynamically linking the services into different workflow configurations. Traditional service-based applications, in fixed networks, are typically constructed and managed centrally and assume stable service endpoints and adequate network connectivity. Constructing and maintaining such applications in dynamic heterogeneous wireless networked environments, where limited bandwidth and transient connectivity are commonplace, presents significant challenges and makes centralized application construction and management impossible. In this paper we present an architecture which is capable of providing an adaptable and resilient method for on-demand decentralized construction and management of complex time-critical applications in such environments. The approach uses a Vector Symbolic Architecture (VSA) to compactly represent an application as a single semantic vector that encodes the service interfaces, workflow, and the time-critical constraints required. By extending existing services interfaces, with a simple cognitive layer that can interpret and exchange the vectors, we show how the required services can be dynamically discovered and interconnected in a completely decentralized manner. We demonstrate the viability of this approach by using a VSA to encode various time-critical data analytics workflows. We show that these vectors can be used to dynamically construct and run applications using services that are distributed across an emulated Mobile Ad-Hoc Wireless Network (MANET). Scalability is demonstrated via an empirical evaluation
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Multimedia delivery in the future internet
The term “Networked Media” implies that all kinds of media including text, image, 3D graphics, audio
and video are produced, distributed, shared, managed and consumed on-line through various networks,
like the Internet, Fiber, WiFi, WiMAX, GPRS, 3G and so on, in a convergent manner [1]. This white
paper is the contribution of the Media Delivery Platform (MDP) cluster and aims to cover the Networked
challenges of the Networked Media in the transition to the Future of the Internet.
Internet has evolved and changed the way we work and live. End users of the Internet have been confronted
with a bewildering range of media, services and applications and of technological innovations concerning
media formats, wireless networks, terminal types and capabilities. And there is little evidence that the pace
of this innovation is slowing. Today, over one billion of users access the Internet on regular basis, more
than 100 million users have downloaded at least one (multi)media file and over 47 millions of them do so
regularly, searching in more than 160 Exabytes1 of content. In the near future these numbers are expected
to exponentially rise. It is expected that the Internet content will be increased by at least a factor of 6, rising
to more than 990 Exabytes before 2012, fuelled mainly by the users themselves. Moreover, it is envisaged
that in a near- to mid-term future, the Internet will provide the means to share and distribute (new)
multimedia content and services with superior quality and striking flexibility, in a trusted and personalized
way, improving citizens’ quality of life, working conditions, edutainment and safety.
In this evolving environment, new transport protocols, new multimedia encoding schemes, cross-layer inthe
network adaptation, machine-to-machine communication (including RFIDs), rich 3D content as well as
community networks and the use of peer-to-peer (P2P) overlays are expected to generate new models of
interaction and cooperation, and be able to support enhanced perceived quality-of-experience (PQoE) and
innovative applications “on the move”, like virtual collaboration environments, personalised services/
media, virtual sport groups, on-line gaming, edutainment. In this context, the interaction with content
combined with interactive/multimedia search capabilities across distributed repositories, opportunistic P2P
networks and the dynamic adaptation to the characteristics of diverse mobile terminals are expected to
contribute towards such a vision.
Based on work that has taken place in a number of EC co-funded projects, in Framework Program 6 (FP6)
and Framework Program 7 (FP7), a group of experts and technology visionaries have voluntarily
contributed in this white paper aiming to describe the status, the state-of-the art, the challenges and the way
ahead in the area of Content Aware media delivery platforms
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