Rashid J. Al-Ali

Bio: Rashid J. Al-Ali is an academic researcher from Cardiff University. The author has contributed to research in topics: Grid computing & Mobile QoS. The author has an hindex of 11, co-authored 15 publications receiving 831 citations. Previous affiliations of Rashid J. Al-Ali include University of the Pacific (United States) & Argonne National Laboratory.

UDDIe: an extended registry for Web services

Abstract: The Universal Description, Discovery and Integration (UDDI) is a specification for distributed Web-based information registries for Web Services. UDDI allows HTTP-enabled business services to be published, and subsequently searched, based on their interface. UDDI consists of three components: "white pages" to hold basic contact information and identifiers for a company, "yellow pages" to enable companies to be listed based on their industry categories (using standard taxonomies), and "green pages" to record interface details of how a Web service is to be invoked. UDDI is however limited in scope - allowing white, yellow or green pages to be searched based on a few attributes, and does not provide an automatic mechanism for updating the registry as services (and service providers) change. We implement UDDIe -an extension to UDDI, which supports the notion of "blue pages", to record user defined properties associated with a service - and to enable discovery of services based on these. UDDIe enables a registry to be more dynamic, by allowing services to hold a lease - a time period describing how long a service description should remain in the registry. UDDIe can co-exist with existing UDDI - and has been implemented as open-source software.

G-QOSM: Grid Service Discovery Using QoS Properties

Abstract: We extend the service abstraction in the Open Grid Services Architecture~\cite{ogsa} for Quality of Service (QoS) properties. The realization of QoS often requires mechanisms such as advance or on-demand reservation of resources, varying in type and implementation, and independently controlled and monitored. Foster et al. propose the GARA~\cite{FostKessl99} architecture. The GARA library provides a restricted representation scheme for encoding resource properties and the associated monitoring of Service Level Agreements (SLAs). Our focus is on the application layer, whereby a given service may indicate the QoS properties it can offer, or where a~service may search for other services based on particular QoS properties.

Analysis and Provision of QoS for Distributed Grid Applications

Abstract: Grid computing provides the infrastructure necessary to access and use distributed resources as part of virtual organizations. When used in this way, Grid computing makes it possible for users to participate in collaborative and distributed applications such as tele-immersion, visualization, and computational simulation. Some of these applications operate in a collaborative mode, requiring data to be stored and delivered in a timely manner. This class of applications must adhere to stringent real-time constraints and Quality-of-Service (QoS) requirements. A QoS management approach is therefore required to orchestrate and guarantee the timely interaction between such applications and services. We discuss the design and a prototype implementation of a QoS system, and demonstrate how we enable Grid applications to become QoS compliant. We validate this approach through a case study of an image processing task derived from a nanoscale structures application.

QoS Adaptation in Service-Oriented Grids.

Abstract: Some applications utilizing Grid computing infrastructure require the simultaneous allocation of resources, such as compute servers, networks, memory, disk storage and other specialized resources. Collaborative working and visualization is one example of such applications. In this context, Quality of Service (QoS) is related to Grid services, and not just to the network connecting these services. With the emerging interest in service-oriented Grids, resources may be advertised and traded as services based on a Service Level Agreement (SLA). Such a SLA must include both general and technical specifications, including pricing policy and properties of the resources required to execute the service – to ensure QoS requirements are satisfied. A QoS adaptation algorithm is presented to enable the dynamic adjustment of behavior of an application based on changes in the pre-defined SLA. The approach is particularly useful if workload or network traffic changes in unpredictable ways during an active session. The proposed QoS adaptation scheme is used to compensate for QoS degradation and optimize resource utilization, by increasing the number of requests managed over a particular time.

Supporting QoS-based discovery in service-oriented Grids

Abstract: In this paper the service abstraction is extended to support quality of service (QoS) attributes - and implemented in the Grid QoS Management (G-QoSM) framework. The framework supports three main functions: (1) providing mechanisms for establishing QoS guarantees via service level agreements (SLAs), (2) enabling QoS management on allocated QoS-aware services, and (3) supporting discovery of services based on QoS attributes. The framework relies on each service offering both a "functional" interface and a "management" interface. The functional interface provides attributes on how a service is to be invoked and how it returns results, whereas the management interface is used to provide QoS attributes and performance characteristics associated with a service. The focus of this paper is on implementing a QoS-based service discovery system, which utilises an extended version of the universal description, discovery and integration (UDDI) registry.

QoS-based Discovery and Ranking of Web Services

Abstract: Discovering Web services using keyword-based search techniques offered by existing UDDI APIs (i.e. Inquiry API) may not yield results that are tailored to clients' needs. When discovering Web services, clients look for those that meet their requirements, primarily the overall functionality and quality of service (QoS). Standards such as UDDI, WSDL, and SOAP have the potential of providing QoS-aware discovery, however, there are technical challenges associated with existing standards such as the client's ability to control and manage discovery of Web services across accessible service registries. This paper proposes a solution to this problem and introduces the Web service relevancy function (WsRF) used for measuring the relevancy ranking of a particular Web service based on client's preferences, and QoS metrics. We present experimental validation, results, and analysis of the presented ideas.

Personalized QoS Prediction forWeb Services via Collaborative Filtering

Abstract: Many researchers propose that, not only functional but also non-functional properties, also known as quality of service (QoS), should be taken into consideration when consumers select services. Consumers need to make prediction on quality of unused web services before selecting. Usually, this prediction is based on other consumers' experiences. Being aware of different QoS experiences of consumers, this paper proposes a collaborative filtering based approach to making similarity mining and prediction from consumers' experiences. Experimental results demonstrate that this approach can make significant improvement on the effectiveness of QoS prediction for web services.

A game-theoretic method of fair resource allocation for cloud computing services

Abstract: As cloud-based services become more numerous and dynamic, resource provisioning becomes more and more challenging. A QoS constrained resource allocation problem is considered in this paper, in which service demanders intend to solve sophisticated parallel computing problem by requesting the usage of resources across a cloud-based network, and a cost of each computational service depends on the amount of computation. Game theory is used to solve the problem of resource allocation. A practical approximated solution with the following two steps is proposed. First, each participant solves its optimal problem independently, without consideration of the multiplexing of resource assignments. A Binary Integer Programming method is proposed to solve the independent optimization. Second, an evolutionary mechanism is designed, which changes multiplexed strategies of the initial optimal solutions of different participants with minimizing their efficiency losses. The algorithms in the evolutionary mechanism take both optimization and fairness into account. It is demonstrated that Nash equilibrium always exists if the resource allocation game has feasible solutions.

Toward autonomic web services trust and selection

Abstract: Emerging Web services standards enable the development of large-scale applications in open environments. In particular, they enable services to be dynamically bound. However, current techniques fail to address the critical problem of selecting the right service instances. Service selection should be determined based on user preferences and business policies, and consider the trustworthiness of service instances.We propose a multiagent approach that naturally provides a solution to the selection problem. This approach is based on an architecture and programming model in which agents represent applications and services. The agents support considerations of semantics and quality of service (QoS). They interact and share information, in essence creating an ecosystem of collaborative service providers and consumers. Consequently, our approach enables applications to be dynamically configured at runtime in a manner that continually adapts to the preferences of the participants. Our agents are designed using decision theory and use ontologies. We evaluate our approach through simulation experiments.

RATEWeb: Reputation Assessment for Trust Establishment among Web services

Abstract: We introduce RATEWeb, a framework for establishing trust in service-oriented environments. RATEWeb supports a cooperative model in which Web services share their experiences of the service providers with their peers through feedback ratings. The different ratings are aggregated to derive a service provider's reputation. This in turn is used to evaluate trust. The overall goal of RATEWeb is to facilitate trust-based selection and composition of Web services. We propose a set of decentralized techniques that aim at accurately aggregating the submitted ratings for reputation assessment. We conduct experiments to assess the fairness and accuracy of the proposed techniques.