Issue 3 • Date July-Sept. 2013
With the increasing presence and adoption of web services on the World Wide Web, the demand of efficient web service quality evaluation approaches is becoming unprecedentedly strong. To avoid the expensive and time-consuming web service invocations, this paper proposes a collaborative quality-of-service (QoS) prediction approach for web services by taking advantages of the past web service usage experiences of service users. We first apply the concept of user-collaboration for the web service QoS information sharing. Then, based on the collected QoS data, a neighborhood-integrated approach is designed for personalized web service QoS value prediction. To validate our approach, large-scale real-world experiments are conducted, which include 1,974,675 web service invocations from 339 service users on 5,825 real-world web services. The comprehensive experimental studies show that our proposed approach achieves higher prediction accuracy than other approaches. The public release of our web service QoS data set provides valuable real-world data for future research. View full abstract»
With the widespread adoption of cloud computing, the ability to record and account for the usage of cloud resources in a credible and verifiable way has become critical for cloud service providers and users alike. The success of such a billing system depends on several factors: The billing transactions must have integrity and nonrepudiation capabilities; the billing transactions must be nonobstructive and have a minimal computation cost; and the service level agreement (SLA) monitoring should be provided in a trusted manner. Existing billing systems are limited in terms of security capabilities or computational overhead. In this paper, we propose a secure and nonobstructive billing system called THEMIS as a remedy for these limitations. The system uses a novel concept of a cloud notary authority for the supervision of billing. The cloud notary authority generates mutually verifiable binding information that can be used to resolve future disputes between a user and a cloud service provider in a computationally efficient way. Furthermore, to provide a forgery-resistive SLA monitoring mechanism, we devised a SLA monitoring module enhanced with a trusted platform module (TPM), called S-Mon. The performance evaluation confirms that the overall latency of THEMIS billing transactions (avg. 4.89 ms) is much shorter than the latency of public key infrastructure (PKI)-based billing transactions (avg. 82.51 ms), though THEMIS guarantees identical security features as a PKI. This work has been undertaken on a real cloud computing service called iCubeCloud. View full abstract»
User-perceived performance continues to be the most important QoS indicator in cloud-based data centers today. Effective allocation of virtual machines (VMs) to handle both CPU intensive and I/O intensive workloads is a crucial performance management capability in virtualized clouds. Although a fair amount of researches have dedicated to measuring and scheduling jobs among VMs, there still lacks of in-depth understanding of performance factors that impact the efficiency and effectiveness of resource multiplexing and scheduling among VMs. In this paper, we present the experimental research on performance interference in parallel processing of CPU-intensive and network-intensive workloads on Xen virtual machine monitor (VMM). Based on our study, we conclude with five key findings which are critical for effective performance management and tuning in virtualized clouds. First, colocating network-intensive workloads in isolated VMs incurs high overheads of switches and events in Dom0 and VMM. Second, colocating CPU-intensive workloads in isolated VMs incurs high CPU contention due to fast I/O processing in I/O channel. Third, running CPU-intensive and network-intensive workloads in conjunction incurs the least resource contention, delivering higher aggregate performance. Fourth, performance of network-intensive workload is insensitive to CPU assignment among VMs, whereas adaptive CPU assignment among VMs is critical to CPU-intensive workload. The more CPUs pinned on Dom0 the worse performance is achieved by CPU-intensive workload. Last, due to fast I/O processing in I/O channel, limitation on grant table is a potential bottleneck in Xen. We argue that identifying the factors that impact the total demand of exchanged memory pages is important to the in-depth understanding of interference costs in Dom0 and VMM. View full abstract»
Enforcing access control in composite services is essential in distributed multidomain environment. Many advanced access control models have been developed to secure web services at execution time. However, they do not consider access control validation at composition time, resulting in high execution-time failure rate of composite services due to access control violations. Performing composition-time access control validation is not straightforward. First, many candidate compositions need to be considered and validating them can be costly. Second, some service composers may not be trusted to access protected policies and validation has to be done remotely. Another major issue with existing models is that they do not consider information flow control in composite services, which may result in undesirable information leakage. To resolve all these problems, we develop a novel three-phase composition protocol integrating information flow control. To reduce the policy evaluation cost, we use historical information to efficiently evaluate and prune candidate compositions and perform local/remote policy evaluation only on top candidates. To achieve effective and efficient information flow control, we introduce the novel concept of transformation factor to model the computation effect of intermediate services. Experimental studies show significant performance benefit of the proposed mechanism. View full abstract»
Context-aware web services have been attracting significant attention as an important approach for improving the usability of web services. In this paper, we explore a novel approach to model dynamic behaviors of interacting context-aware web services, aiming to effectively process and take advantage of contexts and realize behavior adaptation of web services and further to facilitate the development of context-aware application of web services. We present an interaction model of context-aware web services based on context-aware process network (CAPN), which is a data-flow and channel-based model of cooperative computation. The CAPN is extended to context-aware web service network by introducing a kind of sensor processes, which is used to catch contextual data from external environment. Through modeling the register link's behaviors, we present how a web service can respond to its context changes dynamically. The formal behavior semantics of our model is described by calculus of communicating systems process algebra. The behavior adaptation and context awareness in our model are discussed. An eXtensible Markup Language-formatted service behavior description language named BML4WS is designed to describe behaviors and behavior adaptation of interacting context-aware web services. Finally, an application case is demonstrated to illustrate the proposed model how to adapt context changes and describe service behaviors and their changes. View full abstract»
As a promising standard of television, Internet protocol television (IPTV) gains increasing popularity with its on-demand services. However, supporting scalable on-demand IPTV services remains to be an important challenge. Existing IPTV architecture dedicates a regional station to serve subscribers in the respective region regardless of temporal and spatial dynamics in service demand. This may cause significant imbalance of resource utilization and service provisioning delay among stations, especially with increasing subscribers and service catalog. In this paper, we propose CiTV, a collaborative Internet TV service platform that achieves efficient and scalable IPTV service delivery through interstation collaboration. First, CiTV employs a novel request dispatching algorithm that enables stations to autonomously dispatch requests among themselves and achieves low per-view cost and load variance at the same time. Second, CiTV also leverages a distributed content placement algorithm to globally optimize content utilization at multistation level, which is important for deployment scalability. Last but not the least, CiTV also ensures service delivery quality and efficiency through fine-grained collaboration scope control. We perform both theoretical and empirical analysis of CiTV. Our experiment results suggest that CiTV significantly improves the scalability of on-demand IPTV services for the existing IPTV architecture. View full abstract»
Quality of service (QoS) is a major concern in the design and management of a composite service. In this paper, a systematic approach is proposed to calculate QoS for composite services with complex structures, taking into consideration of the probability and conditions of each execution path. Four types of basic composition patterns for composite services are discussed: sequential, parallel, loop, and conditional patterns. In particular, QoS solutions are provided for unstructured conditional and loop patterns. We also show how QoS-based service selection can be conducted based on the proposed QoS calculation. Experiments have been conducted to show the effectiveness of the proposed method. View full abstract»
Web services (WSs) can cooperate with each other to provide more valuable WSs. Current approaches for WS cooperation have typically assumed that WSs are always willing to participate in some form of cooperation, and have undermined the fact that WSs are autonomous in this open environment. This assumption, however, becomes more problematic in community-based WS cooperation due to the dynamic nature of WS community. It is, therefore, important to devise a cooperation scheme respecting WS autonomy for community-based WS cooperation. In this paper, we model the community-based cooperation among autonomous WSs as a coalitional game in graph form. We show this game is non-cohesive and design a distributed coalition formation algorithm. We prove that the proposed algorithm can lead to an individually stable coalition partition, which indicates that every WS can maximize its benefit through cooperation without decreasing other WSs' benefit. We also conduct extensive simulations, and the results show that the proposed algorithm can greatly improve the average payoff per WS and average availability per coalition when compared with other cooperation schemes. View full abstract»
The transfer of streaming data is not well supported by current web services standards. To include multimedia streaming support in the web services domain, this paper presents a novel multimedia streaming web services framework for the transfer of streaming multimedia content. First, the framework includes an implementation of a query service for publishing a description of the multimedia content that is input to or output from a multimedia web service. This query service is specified in an extension of WSDL. Using MPEG-7 metadata, content descriptions can be queried before the invocation of a multimedia web service. Second, two new MEPs and their SOAP HTTP bindings are created for the exchange of streaming data between two SOAP endpoints. The implementations of these new MEPs use the MIME multipart/related structure and MTOM packaging when transferring the multimedia packets as SOAP messages. To reduce the transfer overhead introduced by the packaging method, this paper investigated extensively the application of various compression schemes for the SOAP messages as well as for the packaging of the binary packet data. Experiments show that the proposed framework can achieve a performance comparable to a simple HTTP multimedia streaming method. View full abstract»
This paper describes a novel model for the service selection problem of workflow-based applications in the context of self-managing situated computing. In such systems, the execution environment includes different types of devices, from remote servers to personal notebooks, smartphones, and wireless sensors, which build an infrastructure that can dynamically change both its physical and logical architecture at runtime. We assume that workflows are defined abstractly; i.e., they invoke abstract services whose concrete counterparts can be selected dynamically. We also assume that concrete service implementations may possibly migrate on the nodes of the infrastructure. The selection problem we address is framed as an optimization problem of the quality of service (QoS), which evaluates at runtime the optimal binding to concrete services as well as the tradeoff between the remote execution of software fragments and their dynamic deployment on local nodes of the computational environment. The final deployment takes into account quality of service constraints, the capabilities of the physical devices involved, including their performance and energy consumption, and the characteristics of the networking links connecting them. View full abstract»
Aims & Scope
The scope covers all computing and software aspects of the science and technology of services innovation research and development. IEEE Transactions on Services Computing emphasizes the algorithmic, mathematical, statistical and computational methods that are central in services computing, the emerging field of Service Oriented Architecture, Web Services, Business Process Integration, Solution Performance Management, Services Operations and Management. Specifically, the transactions covers but is not limited to the following topics: Mathematical foundation of Services Computing, Service-Oriented Architecture (SOA), Service creation, development, and management, Linkage between IT services and business services, Web services security and privacy, Web services agreement and contract, Web services discovery and negotiation, Web services management, Web services collaboration, Quality of Service for Web services, Web services modeling and performance management, Solution frameworks for building service-oriented applications, Composite Web service creation and enabling infrastructures, Business and scientific applications using Web services and SOA, Business process integration and management using Web services, Standards and specifications of Services Computing, Utility models and solution architectures, Resource acquisition models in Utility Computing, Mathematical foundation of business process modeling, integration and management, Business process modeling, integration, and collaboration.
TSC is a scholarly, archival journal published quarterly.
It is noted that only service-oriented grid computing topics will be covered by TSC.
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Georgia Institute of Technology