http://www.computer.org/tsc The IEEE Transactions on Services Computing will emphasize 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, this new title covers but not limited to the following topics: a) Mathematical foundation of Services Computing; b) Service-Oriented Architecture (SOA); c) Service creation, development, and management; d) Linkage between IT services and business services; e) Web services security and privacy; f) Web services agreement and contract; g) Web services discovery and negotiation; h) Web services management; i) Web services collaboration; j) Quality of Service for Web Services; k) Web services modeling and performance management; l) Solution frameworks for building service-oriented applications; m) Composite Web service creation and enabling infrastructures; n) Business and scientific applications using Web services and SOA; o) Business process integration and management using Web Services; p) Standards and specifications of Services Computing; q) Utility Models and Solution Architectures; r) Resource acquisition models in Utility Computing; s) Mathematical foundation of business process modeling, integration and management; t) Business process modeling, integration, and collaboration. It is noted that only Web service-oriented Grid computing will be covered by Services Computing. en-us Thu, 23 May 2013 10:00:05 GMT http://csdl.computer.org/common/images/logos/tsc.gif List of recently published journal articles http://www.computer.org/tsc http://doi.ieeecomputersociety.org/10.1109/TSC.2013.24 Increasing number of the cloud-based Internet applications demands for efficient resource and cost management. This paper proposes a real-time group auction system for the cloud instance market. The system is designed based on a combinatorial double auction, and its applicability and effectiveness are evaluated in terms of resource efficiency and monetary benefits to auction participants (e.g., cloud users and providers). The proposed auction system assists them to decide when and how providers allocate their resources to which users. Furthermore, we propose a distributed algorithm using a group formation game that determines which users and providers will trade resources by their cooperative decisions. To find how to allocate the resources, the utility optimization problem is formulated as a binary integer programming problem, and the nearly optimal solution is obtained by a heuristic algorithm with quadratic time complexity. In comparison studies, the proposed real-time group auction system with cooperation outperforms an individual auction in terms of the resource efficiency (e.g., the request acceptance rate for users and resource utilization for providers) and monetary benefits (e.g., average payments for users and total profits for providers). http://doi.ieeecomputersociety.org/10.1109/TSC.2013.24 http://doi.ieeecomputersociety.org/10.1109/TSC.2013.9 WS-Agreement is one of the most widely used SLA specifications. An advantage of WS-Agreement over other agreement metamodels is that it allows one to define conditional and optional term sets inside an agreement document, which are commonly found features in real-world agreements. Unfortunately, they increase the complexity of the automated detection and explanation of conflicts between SLA terms, leading to new kind of conflicts that are not supported by current techniques. Furthermore, creating a general-purpose conflict analyser in WS-Agreement is a hard task since it should understand the semantics of an unbounded number of languages that can be used in the eight extension points that WS-Agreement includes for the sake of flexibility. In this article we address these issues by providing a conflict classification for SLAs that includes new conflicts derived from the use of conditional and optional term sets; and a novel, language-agnostic technique based on constraint satisfaction problems to automatically detect and explain these conflicts. In pursuing these results, we defined some WS-Agreement concepts as well as a fully-fledged WS-Agreement-compliant language. The developed technique and its reference implementation have been thoroughly validated. http://doi.ieeecomputersociety.org/10.1109/TSC.2013.9 http://doi.ieeecomputersociety.org/10.1109/TSC.2013.8 Dependability is an important consideration during the design and development of IT systems and services. But in services computing systems, the traditional definition and evaluation methods from the systems' and components' point of view meet challenges. In this paper, we veer from the angle of view, and study the dependability and their attributes from the service-oriented perspective. A stochastic model using semi-Markov process is put forward, and the quantitative analysis of the dependability attributes is carried out. By extending and transforming this model, the mean time to dependability attributes failure is calculated. Based on the analysis and calculations, some theorems are proposed and proved, to show the inter-relationships and comparisons of the different dependability attributes. Furthermore, we model the service composition and conduct workflow analysis to show how this model could deal with complex services. In addition, LANL service systems are analyzed as a case study to show how the proposed model and calculation methods could apply to real systems, and sensitivity analysis is also performed to identify the bottlenecks and find effective ways for dependability optimization. http://doi.ieeecomputersociety.org/10.1109/TSC.2013.8 http://doi.ieeecomputersociety.org/10.1109/TSC.2013.5 Currently, we are witnessing a proliferation in the number of cloud-hosted applications with a tremendous increase in the scale of the data generated as well as being consumed by such applications. The specifications of existing service level agreements (SLA) for cloud services are not designed to flexibly handle even relatively straightforward performance and technical requirements of consumer applications. In this article, we present a novel approach for SLA-based management of cloud-hosted databases from the consumer perspective. The framework facilitates adaptive and dynamic provisioning of the database tier of the software applications based on application-defined policies for satisfying their own SLA performance requirements, avoiding the cost of any SLA violation and controlling the monetary cost of the allocated computing resources. In this framework, the SLA of the consumer applications are declaratively defined in terms of goals which are subjected to a number of constraints that are specific to the application requirements. The framework continuously monitors the application-defined SLA and automatically triggers the execution of necessary corrective actions (scaling out/in the database tier) when required. The experimental results demonstrate the effectiveness of our SLA-based framework in providing the consumer applications with the required flexibility for achieving their SLA requirements. http://doi.ieeecomputersociety.org/10.1109/TSC.2013.5 http://doi.ieeecomputersociety.org/10.1109/TSC.2013.2 Service-Oriented Computing enables the composition of loosely coupled services provided with varying Quality of Service (QoS) levels. Selecting a near-optimal set of services for a composition in terms of QoS is crucial when many functionally equivalent services are available. As the number of distributed services, especially in the cloud, is rising rapidly, the impact of the network on the QoS keeps increasing. Despite this, current approaches do not differentiate between the QoS of services themselves and the network. Therefore, the computed latency differs from the actual latency, resulting in suboptimal QoS. Thus, we propose a network-aware approach that handles the QoS of services and the QoS of the network independently. First, we build a network model in order to estimate the network latency between arbitrary services and potential users. Our selection algorithm then leverages this model to find compositions with a low latency for a given execution policy. We employ a self-adaptive genetic algorithm which balances the optimization of latency and other QoS as needed and improves the convergence speed. In our evaluation, we show that our approach works under realistic network conditions, efficiently computing compositions with much lower latency and otherwise equivalent QoS compared to current approaches. http://doi.ieeecomputersociety.org/10.1109/TSC.2013.2 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.32 Advancements in cloud computing enable the easy deployment of numerous services. However, the analysis of cloud service access platforms from a client perspective shows that maintaining and managing clients remain a challenge for end-users. In this paper, we present the design, implementation, and evaluation of an asymmetric virtual machine monitor (AVMM), which is an asymmetric partitioning-based bare-metal approach that achieves near-native performance while supporting a new out-of-operating system mechanism for value-added services. To achieve these goals, AVMM divides underlying platforms into two asymmetric partitions: a user partition and a service partition. The user partition runs a commodity user OS, which is assigned to most of the underlying resources, maintaining end-user experience. The service partition runs a specialized OS, which consumes only the needed resources for its tasks and provides enhanced features to the user OS. AVMM considerably reduces virtualization overhead through two approaches: (1) Peripheral devices, such as graphics equipment, are assigned to be monopolized by a single user OS. (2) Efficient resource management mechanisms are leveraged to alleviate complicated resource sharing in existing virtualization technologies. We implement a prototype that supports Windows and Linux systems. Experimental results show that AVMM is a feasible and efficient approach to client virtualization. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.32 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.26 Service modeling and service composition are software architecture paradigms that have been used extensively in web services where there is an abundance of resources. They mainly capture the idea that advanced functionality can be realized by combining a set of primitive services provided by the system. Many efforts in web services domain focused on detecting the initial composition, which is then followed for the rest of service operation. In sensor networks however, communication among nodes is error-prone and unreliable, while sensor nodes have constrained resources. This dynamic environment requires a continuous adaptation of the composition of a complex service. In this paper, we first propose a graph-based formulation for modeling sensor services that maps to the operational model of sensor networks and is amenable to analysis. Based on this model, we formulate the process of sensor service composition as a cost-optimization problem and show that it is NP-complete. Two heuristic methods are proposed to solve the composition problem: the top-down and the bottom-up approaches.We discuss centralized and distributed implementations of these methods. Finally, using ns-2 simulations, we evaluate the performance and overhead of our proposed methods. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.26 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.14 Recently, the evolution and widespread adoption of virtualization, SOA, autonomic, and utility computing have converged letting a new paradigm to emerge: Cloud computing. Currently the Cloud offer is becoming wider and wider, since all the major IT Companies and Service providers have started providing solutions. As Cloud-based services are more numerous and dynamic, the development of efficient service provisioning policies becomes increasingly challenging. In this paper we take the perspective of SaaS providers which host their applications at an IaaS. Each SaaS needs to comply with QoS requirements, specified in SLA contracts with the end-users, which determine the revenues and penalties on the basis of the achieved performance level. SaaS providers want to maximize their revenues from SLAs, while competing and bidding for the use of infrastructural resources. In this paper we model the service provisioning problem as a generalized Nash game and we show the existence of equilibria for such game. Moreover, we propose two solution methods based on the best-reply dynamics and we prove their convergence in a finite number of iterations to a generalized Nash equilibrium. We demonstrate the effectiveness of our approach by simulation and performing tests on a real prototype environment deployed on Amazon EC2. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.14 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.23 E-contract evolves over a period of time due to changes in e-contract environment. E-contract evolution adversely affects the execution of e-contracts. An e-contract is specified by a model at conceptual level, supported by a DBMS at logical level and by both DBMS and Workflow Management System at implementation level. Any changes in the design as well as run-time environment during e-contract enactment must be reflected at all levels. Conventional modeling approaches simply model the e-contracts as specified workflows and execute them. Since, e-contracts are complex in nature, such models have to undergo large number of transformations during e-contract enactment. Meta-modeling approach guides the correctness of transformed models by generating appropriate model instances according to e-contract constraints in order to support evolution. A meta-model has structural artifacts to capture the relationships among contract elements and model the required specifications and semantics present in an e-contract as a template. In this paper, we develop (i) an active meta-modeling approach by (a) introducing the taxonomy of evolution operations and (b) handling meta-events to facilitate the structural and behavioural conformance during e-contracts evolution, and (ii)an ER*EC architecture for enacting evolving e-contracts. Our methodology actively capture behaviour features from e-contract executions to drive e-contract evolution. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.23 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.15 The service-oriented architecture style supports desirable qualities, including distributed, loosely-coupled systems spanning organizational boundaries. Such systems and their configurations are challenging to understand, reason about, and test. Improved understanding of these systems will support activities such as autonomic run-time configuration, application deployment, and development/testing. Simulation is one way to understand and test service systems. This paper describes a literature survey of simulation frameworks for service-oriented systems, examining simulation software, systems, approaches, and frameworks used to simulate service-oriented systems. We identify a set of dimensions for describing the various approaches, considering their modeling methodology, their functionalities, their underlying infrastructure, and their evaluation. We then introduce the Services-Aware Simulation Framework (SASF), a simulation framework for predicting the behavior of service-oriented systems under different configurations and loads, and discuss the unique features that distinguish it from other systems in the literature. We demonstrate its use in simulating two service-oriented systems. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.15 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.12 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. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.12 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.1 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 have a minimal computation cost; and the 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. It 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. This work has been undertaken on a real cloud computing service called iCubeCloud. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.1 http://doi.ieeecomputersociety.org/10.1109/TSC.2013.27 With the recent widespread adoption of service-oriented architecture, the dynamic composition of services is now a crucial issue in the area of distributed computing. The coordination and execution of composite Web services are today typically conducted by heavyweight centralized workflow engines, leading to an increasing probability of processing and communication bottleneck and failures. In a world where platforms are more and more dynamic and elastic as promised by cloud computing, decentralized and dynamic interaction schemes are required. Addressing the characteristics of such platforms, nature-inspired analogies recently regained attention to provide autonomous service coordination on top of dynamic large scale platforms. In this paper, we propose a approach for the decentralized execution ofcomposite Web services based on an unconventional programming paradigm that relies on the chemical metaphor. It provides a high-level execution model that allows executing composite services in a decentralized manner. Composed of services communicating through a persistent shared space containing control and data flows between services, our architecture allows to distribute the composition coordination among nodes. A proof of concept is given, through the deployment of a software prototype implementing these concepts, showing the viability of an autonomic vision of service composition. http://doi.ieeecomputersociety.org/10.1109/TSC.2013.27 http://doi.ieeecomputersociety.org/10.1109/TSC.2013.26 Service identification is one of the main phases in the design of a service-oriented application. The way in which services are identified may influence the effectiveness of the SOA architecture. More specifically, the granularity of the services is very important in reaching flexibility and reusing them. Such properties are crucial in inter-organizational interactions based on collaborative business processes. In fact, collaboration is facilitated by ensuring a homogeneous description of services at the right level of granularity. In this paper, we provide a detailed description of P2S (Process-to-Services), a computer aided methodology to enable the identification of services that compose a collaborative business process. The methodology is based on metrics defined to setup service granularity, cohesion, coupling and reuse. A prototype tool based on the methodology is also described with reference to a real case scenario. http://doi.ieeecomputersociety.org/10.1109/TSC.2013.26 http://doi.ieeecomputersociety.org/10.1109/TSC.2013.25 Cloud computing has changed the way organizations create, manage, and evolve heir applications. While the abundance of computing resources at low cost opens up many possibilities for migrating applications to the cloud, this migration also comes at a price. Cloud applications, in many cases, depend on certain provider specific features or services. In moving applications to the cloud, application developers face the challenge of balancing these dependencies to avoid vendor lock-in. We present an abstraction-driven approach to address the application portability issues and focus on the application development process. We also present our theoretical basis and experience in two practical projects where we have applied the abstraction driven approach. http://doi.ieeecomputersociety.org/10.1109/TSC.2013.25 http://doi.ieeecomputersociety.org/10.1109/TSC.2013.23 By discovering and reusing relevant web services, an organization can select and compose those services that most closely meet its business and Quality of Service (QoS) needs. As the number of available web services increases, selecting the best fit services for a given task becomes more challenging. QoS attributes play a significant role in the selection process by directing service composition constraints to a workflow plan that has the best QoS values. Two major problems arise at runtime when undesirable events necessitate the need to reselect services and replan the service bindings. First, if the reselection process consumes additional time, it can impact a temporal QoS constraint. Second, the newly generated composition might not comply with other QoS constraints imposed on the plan. This paper proposes an approach to composing web services that both performs reselection and avoids the violation of QoS constraints after replanning by defining and evaluating a replaceability property. Replaceability factors directly into the algorithm's original service selection process considering all QoS constraints. http://doi.ieeecomputersociety.org/10.1109/TSC.2013.23 http://doi.ieeecomputersociety.org/10.1109/TSC.2013.22 The cost of electricity contributes significantly to the operating expense incurred in hosting cloud services. It is necessary to consider this cost while charging the consumers for their service utilization. In this work, we arrive at a metering mechanism for cloud services, in which the price of a cloud service tracks the input cost of electricity. The power-aware cloud metering developed here is a dynamic pricing and billing model where tariff for a cloud service is varied in accordance with the input electricity cost. We arrive at a model for power consumption of virtual machines hosted on the cloud infrastructure. This power consumption model is used in calculating the cost of operation of the service. A cloud instance leased by a consumer is billed based on the cost of operation obtained and its resource utilization. Experimental results validate the approach presented. http://doi.ieeecomputersociety.org/10.1109/TSC.2013.22 http://doi.ieeecomputersociety.org/10.1109/TSC.2013.21 Contracts are legally binding descriptions of business service engagements. In particular, we consider business events as elements of a service engagement. Business events such as purchase, delivery, bill payment, bank interest accrual not only correspond to essential processes but are also inherently temporally constrained. Identifying and understanding the events and their temporal relationships can help a business partner determine what to deliver and expect from others as it participates in the specified service engagement. However, contracts are expressed in unstructured text and their insights are buried therein. Our contributions are threefold. We develop a novel approach employing a hybrid of surface patterns, grammar parsing, and classification to (1) extract business events and (2) their temporal constraints from contract text. We use topic modeling to (3) automatically organize the event terms into clusters. An evaluation on a real-life contract dataset demonstrates the viability and promise of our hybrid approach, yielding an F-measure of 0.89 in event extraction and 0.90 in temporal constraints extraction. The topic model yields event term clusters with an average match of 85% between two independent human annotations and an expert-assigned set of class labels for the clusters. http://doi.ieeecomputersociety.org/10.1109/TSC.2013.21 http://doi.ieeecomputersociety.org/10.1109/TSC.2013.20 Web services have had a tremendous impact on the Web for supporting a distributed service-based economy on a global scale. However, despite the outstanding progress, their uptake on a Web scale has been significantly less than initially anticipated. The isolation of services and the lack of social relationships among related services have been identified as reasons for the poor uptake. In this paper, we propose connecting the isolated service islands into a global social service network to enhance the services' sociability on a global scale. First, we propose linked social service-specific principles based on linked data principles for publishing services on the open Web as linked social services; then, we suggest a new framework for constructing the global social service network following linked social service-specific principles based on complex network theories. Next, an approach is proposed to enable the exploitation of the global social service network, providing Linked Social Services as a Service. Finally, experimental results show that our approach can solve the quality of service discovery problem, improving both the service discovering time and the success rate by exploring service-to-service based on the global social service network. http://doi.ieeecomputersociety.org/10.1109/TSC.2013.20 http://doi.ieeecomputersociety.org/10.1109/TSC.2013.19 Since the behavior is the essential characteristic of business process models, and ordering relations between execution of tasks can be used to describe the behavior of process models, we need to compute the ordering relations between tasks in process models. This computation can be used for compliance checking and querying process models based on behavior. There are three types of ordering relations, i.e. causal, conflict and concurrency. In this paper, we refine the causal and concurrency relations with uncertainty according to whether one task is always executed with the other task in the same instance. To compute the refined ordering relations with uncertainty efficiently, we propose some rules for adjacent tasks and some transitive laws for non-adjacent tasks together with their proofs. Based on these rules and laws, we propose an algorithm to compute the refined ordering relations for acyclic process models based on unfolding technology. The algorithm has a biquadrate time to the size of complete prefix unfolding of the original model. http://doi.ieeecomputersociety.org/10.1109/TSC.2013.19 http://doi.ieeecomputersociety.org/10.1109/TSC.2013.18 Data as a Service (DaaS) builds on service-oriented technologies to enable fast access to data resources on the Web. However, this paradigm raises several new privacy concerns that traditional privacy models do not handle. In addition, DaaS composition may reveal privacy-sensitive information. In this paper, we propose a formal privacy model in order to extend DaaS descriptions with privacy capabilities. The privacy model allows a service to define a privacy policy and a set of privacy requirements. We also propose a privacy-preserving DaaS composition approach allowing to verify the compatibility between privacy requirements and policies in DaaS composition. We propose a negotiation mechanism that makes it possible to dynamically reconcile the privacy capabilities of services when incompatibilities arise in a composition. We validate the applicability of our proposal through a prototype implementation and a set of experiments. http://doi.ieeecomputersociety.org/10.1109/TSC.2013.18 http://doi.ieeecomputersociety.org/10.1109/TSC.2013.11 Service-orientation paves the way for the Internet of Services (IoS), where millions of services will be available to realize the everyday user applications or tasks. Consequently, as a great number of functionally-equivalent services will be available for a specific user task, the service non-functional aspect should be considered for filtering and selecting among these services. The state-of-the-art approaches in non-functional service discovery exploit constraint solving techniques to optimize the matchmaking time between a service offer and demand pair. However, they do not scale well, as matchmaking time is proportional to the offer number, so they are not yet suitable for the IoS. To this end, this article proposes three novel alternative techniques that intelligently organize the service offer space to improve the overall matchmaking time. These techniques are theoretically and experimentally evaluated. The results show that all techniques optimize the matchmaking time without sacrificing accuracy and that each technique is better in different circumstances. http://doi.ieeecomputersociety.org/10.1109/TSC.2013.11 http://doi.ieeecomputersociety.org/10.1109/TSC.2013.12 Infrastructure as a Service systems use virtual appliances to initiate virtual machines. As virtual appliances encapsulate applications and services with their support environment, their delivery is the most expensive task of the virtual machine creation. Virtual appliance delivery is a well-discussed topic in the field of cloud computing. However, for high efficiency, current techniques require the modification of the underlying IaaS systems. To target the wider adoptability of these delivery solutions, this article proposes the concept of minimal manageable virtual appliances (MMVA) that are capable of updating and configuring their virtual machines without the need to modify IaaS systems. To create MMVAs, we propose to reduce manageable virtual appliances until they become MMVAs. This research also reveals a methodology for appliance developers to incorporate MMVAs in their own appliances to enable their efficient delivery and wider adoptability. Finally, the article evaluates the positive effects of MMVAs on an already existing delivery solution: the Automated Virtual appliance creation Service (AVS). Through experimental evaluation, we present that the application of MMVAs not only increases the adoptability of a delivery solution but it also significantly improves its performance in highly-dynamic systems. http://doi.ieeecomputersociety.org/10.1109/TSC.2013.12 http://doi.ieeecomputersociety.org/10.1109/TSC.2013.10 Business processes play an important role in organizations; however, not enough attention is given to analyzing and modeling errors in them. In this paper we study syntactic and control flow error frequencies in business processes from real industry projects. Our samples come from a number of application domains such as Banking and Capital Markets, Insurance and Healthcare, and Retail. We consider industrial business processes modeled in Business Process Modeling Notation (BPMN) and use graph-theoretic techniques and Petri net-based analyses to detect syntactic and control flow related errors respectively. We then use a set of metrics that capture different network characteristics of the models and study the empirical relations between the metrics and process errors. The major results of the empirical investigation are: (a) multiple edges to or from tasks as well as hanging nodes are the predominant forms of syntactic errors (b) syntactic errors occur frequently in Retail & Logistics domain and significantly less in the Insurance and Healthcare domain and (c) the probability of error occurrence can be modeled as a function of node-size and coefficient of connectivity; the logistic regression model correctly classified 97.6% of the cases, with a sensitivity of 100% and specificity of 86.2%. http://doi.ieeecomputersociety.org/10.1109/TSC.2013.10 http://doi.ieeecomputersociety.org/10.1109/TSC.2013.7 Complex Event Processing (CEP) has so far been implemented in technology and vendor-specific manner. Introducing CEP concepts to the Service Oriented Architecture (SOA) provides an opportunity to enhance the capabilities of SOA. We define a model that supports the CEP usage in SOA where the actual pattern recognition can be done by any external CEP Engine. We define a new service type - a Complex Event Aware (CEA) service that automatically reacts to complex events specified in its interface. The proposed model includes a CEP Manager that provides centralized management of complex events and, through its pluggable adapters, communicates with CEA Services and CEP Engines. It includes a CEP Registry and a CEP Repository enabling versioning and reuse of complex event types, and a CEP Dispatcher providing publish/subscribe communication framework. We design a generic XML schema for abstract complex event type definition and propose new extensions for Service Component Architecture (SCA) and Web Services Description Language (WSDL) specifications, which enable definitions of complex event types and complex event sinks in the CEA Service interface. As a proof-of-concept we develop a prototype implementation for the largest national telecommunication provider and in the real-world scenario show advantages of the proposed model. http://doi.ieeecomputersociety.org/10.1109/TSC.2013.7 http://doi.ieeecomputersociety.org/10.1109/TSC.2013.4 Semantic annotation of web services has been proposed as a solution to the problem of discovering services to fit a particular need, and reusing them appropriately. While there exist tools that assist human users in the annotation task, e.g., Radiant and Meteor-S, no semantic annotation proposal considers the problem of verifying the accuracy of the resulting annotations. Early evidence from workflow compatibility checking suggests that the proportion of annotations that are inaccurate is high, and yet no tools exist to help annotators to test the results of their work systematically before they are deployed for public use. In this paper, we adapt techniques from conventional software testing to the verification of semantic annotations for web service input and output parameters. We present an algorithm for the testing process, and discuss ways in which manual effort from the annotator during testing can be reduced. We also present two adequacy criteria for specifying test cases used as input for the testing process. These criteria are based on structural coverage of the domain ontology used for annotation. The results of an evaluation exercise, based on a collection of annotations for bioinformatics web services, show that defects can be successfully detected by the technique. http://doi.ieeecomputersociety.org/10.1109/TSC.2013.4 http://doi.ieeecomputersociety.org/10.1109/TSC.2013.1 We address the problem of usage license administration in federated settings. This problem arises whenever organizations (such as educational or research groups or institutions) share resources for business and scientific reasons. In such settings, each user's usage of a licensed resource is typically supported by the user's organization. License administration involves satisfying legal requirements while applying organizational strategies for effective resource usage, and carrying out suitable accounting and audit controls. We propose an approach, Licit, wherein an agent represents each resource sharing site and administers licenses in collaboration with other agents. We show how to represent a variety of usage licenses formally as executable policies and provide a simple information model using which each party can specify both the attributes involved in its licenses and how to resolve them. Our architecture naturally accommodates a variety of site-specific (custom) strategies for license administration. Licit has been implemented in a popular open source framework for virtual computing, and yields performance results indicating its practical feasibility. http://doi.ieeecomputersociety.org/10.1109/TSC.2013.1 http://doi.ieeecomputersociety.org/10.1109/TSC.2013.3 The modern information systems on the Internet are often implemented as composite services built from multiple atomic services. These atomic services have their interfaces publicly available while their inner structure is unknown. The quality of the composite service is dependent on both the availability of each atomic service and their appropriate orchestration. In this paper, we present LUCS, a formal model for predicting the availability of atomic web services that enhances the current state-of-the-art models used in service recommendation systems. LUCS estimates the service availability for an ongoing request by considering its similarity to prior requests according to the following dimensions: the user's and service's geographic location, the service load, and the service's computational requirements. In order to evaluate our model, we conducted experiments on services deployed in different regions of the Amazon cloud. For each service, we varied the geographic origin of its incoming requests as well as the request frequency. The evaluation results suggest that our model significantly improves availability prediction when all of the LUCS input parameters are available, reducing the prediction error by 71% compared to the current state-of-the-art. http://doi.ieeecomputersociety.org/10.1109/TSC.2013.3 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.41 Managing virtualized services efficiently over the cloud is an open challenge. Traditional models of software development are not appropriate for the cloud computing domain, where software (and other) services are acquired on demand. In this paper, we describe a new integrated methodology for the lifecycle of IT services delivered on the cloud, and demonstrate how it can be used to represent and reason about services and service requirements and so automate service acquisition and consumption from the cloud. We have divided the IT service lifecycle into five phases of requirements, discovery, negotiation, composition, and consumption. We detail each phase and describe the ontologies that we have developed to represent the concepts and relationships for each phase. To show how this lifecycle can automate the usage of cloud services, we describe a cloud storage prototype that we have developed. This methodology complements previous work on ontologies for service descriptions in that it is focused on supporting negotiation for the particulars of a service and going beyond simple matchmaking. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.41 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.35 Recently, cloud computing rapidly expands as an alternative to conventional computing due to it can provide a flexible, dynamic and resilient infrastructure for both academic and business environments. In public cloud environment, the client moves its data to public cloud server (PCS) and can not control its remote data. Thus, information security is an important problem in public cloud storage, such as data confidentiality, integrity, and availability. In some cases, the client has no ability to check its remote data possession, such as the client is in prison because of comitting crime, on the ocean-going vessel, in the battlefield because of the war, {\em et al}. It has to delegate the remote data possession checking task to some proxy. In this paper, we study proxy provable data possession (PPDP). In public clouds, PPDP is a matter of crucial importance when the client can not perform the remote data possession checking. We study the PPDP system model, security model and design method. Based on the bilinear pairing technique, we design an efficient PPDP protocol. Through security analysis and performance analysis, our protocol is provable secure and efficient. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.35 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.40 Location-based services (LBS) are widely deployed. When the implementation of a LBS-enabled service has evolved, regression testing can be employed to assure the previously established behaviors not having been adversely affected. Proper test case prioritization helps reveal service anomalies efficiently. A key observation is that locations captured in the inputs and the expected outputs of test cases are physically correlated by the LBS-enabled service, and these services heuristically use estimated and imprecise locations for their computations, making these services tend to treat locations in close proximity homogenously. This paper exploits this observation. It proposes a suite of metrics and initializes them to demonstrate input-guided techniques and point-of-interest (POI) aware test case prioritization techniques, differing by whether the location information in the expected outputs of test cases is used. It reports a case study on a stateful LBS-enabled service. The case study shows that the POI-aware techniques can be more effective and more stable than the baseline, which reorders test cases randomly, and the input-guided techniques. We also find that one of the POI-aware techniques, cdist, is either the most effective or the second most effective technique among all the studied techniques in our evaluated aspects. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.40 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.39 Developing robust web services is a difficult task. Field studies show that a large number of web services are deployed with robustness problems (i.e., presenting unexpected behaviors in the presence of invalid inputs). Although several techniques for the identification of robustness problems have been proposed in the past, there is no practical approach to automatically fix those problems. This paper proposes a mechanism that automatically fixes robustness problems in web services. The approach consists of using robustness testing to detect robustness issues and then mitigate those issues by applying inputs verification based on well-defined parameter domains, including domain dependencies between different parameters. This integrated and fully automated methodology has been used to improve three different implementations of the TPC-App web services and several services publicly available on the Internet. Results show that the proposed approach can be easily used to improve the robustness of web services code. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.39 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.34 Quality-of-Service (QoS) is widely employed for describing non-functional characteristics of Web services. Although QoS of Web services has been investigated intensively in the field of service computing, there is a lack of real-world Web service QoS datasets for validating various QoS-based techniques and models. To investigate QoS of real-world Web services and to provide reusable research datasets for future research, we conduct several large-scale evaluations on real-world Web services. Firstly, addresses of 21,358 Web services are obtained from the Internet. Then, three large-scale real-world evaluations are conducted. In our evaluations, more than 30 million real-world Web service invocations are conducted on Web services in more than 80 countries by users from more than 30 counties. Detailed evaluation results are presented in this paper and comprehensive Web service QoS datasets are publicly released online. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.34 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.31 With the increasing of amount of Web services on the Internet, personalized Web service selection and recommendation is becoming more and more important. In this paper, we present a new similarity measure for Web service similarity computation and propose a novel collaborative filtering approach, called normal recovery collaborative filtering, for personalized Web service recommendation. To evaluate the Web service recommendation performance of our approach, we conduct large-scale real-world experiments, involving 5,825 real-world Web services in 73 countries and 339 service users in 30 countries. To the best of our knowledge, our experiment is the largest scale experiment in the field of service computing, improving over the previous record by a factor of 100. The experimental results show that our approach achieves better accuracy than other competing approaches. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.31 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.27 Web service composition (WSC) is the task of combining a chain of connected single services together to create a more complex and value-added composite service. Quality of Service (QoS) has been mostly applied to represent nonfunctional properties of Web services and differentiate those with the same functionality. Many research has been done on QoS-aware WSC. However, existing methods are restricted to predefined workflows, which can incur a couple of limitations, including the lack of guarantee for the optimality on QoS and for the completeness of finding a composite service. In this paper, instead of predefining a workflow for service composition, we propose a novel planning-based approach that can automatically convert a QoS-aware composition task to a planning problem with temporal and numerical features. Furthermore, we use state-of-the-art planners, including an existing one and a self-developed one, to handle complex temporal planning problems with logical reasoning and numerical optimization. Our approach can find a composite service graph with the optimal overall QoS. We implement a prototype system and conduct extensive experiments on large Web service repositories. The experimental results show that our proposed approach largely outperforms existing ones in terms of solution quality and is efficient enough for practical deployment. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.27 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.21 In modern utility computing infrastructures, like Grids and Clouds, one of the significant actions of a Service Provider is to predict the resources needed by the services included in its platform in an automated fashion for service provisioning optimization. Furthermore, a variety of software toolkits exist that implement an extended set of algorithms applicable to workload forecasting. However, their automated use as services in the distributed computing paradigm includes a number of design and implementation challenges. In this paper, a decoupled framework is presented, for taking advantage of software like GNU Octave in the process of creating and using prediction models during the service lifecycle of a SOI. A performance analysis of the framework is also conducted. In this context, a methodology for creating parametric or gearbox services with multiple modes of operations based on the execution conditions is portrayed and is applied to transform the aforementioned service framework in order to optimize service performance. A new estimation algorithm is introduced, that creates performance rules of applications as black boxes, through the creation and usage of genetically optimized artificial neural networks. Through this combination, the critical parameters of the networks are decided through an evolutionary iterative process. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.21 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.20 While many process mining algorithms have been proposed recently, there does not exist a widely-accepted benchmark to evaluate and compare these process mining algorithms. As a result, it can be difficult to choose a suitable process mining algorithm for a given enterprise or application domain. Some recent benchmark systems have been developed and proposed to address this issue. However, evaluating available process mining algorithms against a large set of business models (e.g., in a large enterprise) can be computationally expensive, tedious and time-consuming. This paper investigates a scalable solution that can evaluate, compare and rank these process mining algorithms efficiently, and hence proposes a novel framework that can efficiently select the process mining algorithms that are most suitable for a given model set. In particular, using our framework, only a portion of process models need empirical evaluation and others can be recommended directly via a regression model. As a further optimization, this paper also proposes a metric and technique to select high quality reference models to derive an effective regression model. Experiments using artificial and real datasets show that our approach is practical and outperforms the traditional approach. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.20 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.25 Web services are an emerging technology to implement and integrate business processes within and across enterprises. Service-orientation can be used to decompose complex systems into loosely coupled software components that may run remotely. However, the distributed nature of services complicates the design and analysis of service-oriented systems that support end-to-end business processes. Fortunately, services leave trails in so-called event logs and recent breakthroughs in process mining research make it possible to discover, analyze, and improve business processes based on such logs. Recently, the Task Force on Process Mining released the Process Mining Manifesto. This manifesto is supported by 53 organizations and 77 process mining experts contributed to it. The active participation from end-users, tool vendors, consultants, analysts, and researchers illustrate the growing significance of process mining as a bridge between data mining and business process modeling. In this paper, we focus on the opportunities and challenges for service mining, i.e., applying process mining techniques to services. We discuss the guiding principles and challenges listed in the Process Mining Manifesto and also highlight challenges specific for service-orientated systems. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.25 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.22 Service-based software modeling is considered as an effective technique for developing high-quality service-based systems. One major challenge of this approach is how to effectively utilize existing software services in the process of system modeling to ensure the reliability of the system while reducing the development cost and effort. In this paper, we propose a novel formal engineering framework by integrating an evolutionary service selection approach into a formal engineering method to tackle this problem. In the framework, initial requirements are gradually transformed into a formal design specification through three steps during which existing services are discovered, filtered, selected, and employed. Candidate services are discovered through a keyword-based searching. A static behavior analysis technique is then used to filter the candidate services and a specification-based testing method is adopted to rigorously select the candidate services. The selected services are finally incorporated into the formal design model of the system. We present an empirical case study that was conducted for evaluating the usability of our framework by applying it to develop a Travel Agency System. The result of the study demonstrates several advantages of the framework over existing approaches but meanwhile also shows some limitation in practice. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.22 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.19 Large-scale scientific data analysis projects have catalyzed service-based workflow management systems. We present an approach for integrating user preferences on completion time and workflow accuracy in a workflow composition system. The relationship between workflow execution time and the accuracy of results is exploited by our workflow system. Specifically, our system is equipped with a way for users to define cost models on service completion time and error propagation (prevalent in many scientific and data analysis applications). Together with these models and an ontology for describing Web service and data depedencies, our system plans service-based workflows to answer high level queries. Our system was evaluated under a real service-based environment against user constraints on time, accuracy, and network bandwidth variations. In the worst case in our experiments, we observed an average deviation of 14.3% below the desired time constraints, which suggests that our system is time-conservative. Within varying network bandwidth environments, we can also meet time constraints through sampling, and only a 12.4% deviation below time expectations are observed on average. We further show that, though negotiating with services' error models, our system is capable of planning data reduction measures (e.g., sampling) directly within workflow plans to achieve the desired accuracy. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.19 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.18 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 run-time. We assume that worflows 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, which evaluates at run-time the optimal binding to concrete services as well as the trade-off 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. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.18 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.16 The availability of large volumes of Semantic Web data has created the potential of discovering vast amounts of knowledge. Semantic relation discovery is a fundamental technology in analytical domains, such as business intelligence and homeland security. Because of the decentralized and distributed nature of Semantic Web development, semantic data tends to be created and stored independently in different organizations. Under such circumstances, discovering semantic relations faces numerous challenges, such as isolation, scalability, and heterogeneity. This paper proposes an effective strategy to discover semantic relationships over large-scale distributed networks based on a novel hierarchical knowledge abstraction and an efficient discovery protocol. The approach will effectively facilitate the realization of the full potential of harnessing the collective power and utilization of the knowledge scattered over the Internet. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.16 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.13 Modern scientific data management and analysis usually rely on multiple scientists with diverse expertise. In recent years, such a collaborative effort is often composed as and automated by a dataflow-oriented process called scientific workflow. However, such workflows may have to be designed and revised among multiple scientists over a long time period. Existing workbenches are single user-oriented and do not support scientific workflow application development in a "collaborative fashion." In this paper, we report our research on enabling collaboration techniques in the aspect of collaboration provenance management and reproduciability. Based on a scientific collaboration ontology, we propose a service-oriented collaboration model supported by a set of composable collaboration primitives and patterns. The collaboration protocols are then applied to support effective concurrency control in the process of collaborative workflow composition. We also report the design and development of Confucius, a service-oriented collaborative scientific workflow composition tool that extends an open-source, single-user environment. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.13 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.7 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. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.7 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.6 Context-aware web services have been attracting significant attention as an important approach to improve the usability of web services. In this paper, we explore a novel approach to model dynamic behaviors of interacting context-aware web services. It aims to effectively process and take advantage of contexts and realize behavior adaptation of web services, 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 dataflow and channel based model of cooperative computation. 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 (CCS) process algebra. The behavior adaptation and context-awareness in our model are discussed. A XML (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 context, service behaviours and their changes. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.6 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.4 As a promising standard of 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 inter-station 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 multi-station 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. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.4 http://doi.ieeecomputersociety.org/10.1109/TSC.2012.2 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 critical management capability in virtualized clouds. Although a fair amount of research have dedicated to measuring and scheduling jobs among VMs, there still lacks of in-depth understanding of interference factors that impact the efficiency and effectiveness of resource multiplexing and scheduling. In this paper, we present experimental study on performance interference in parallel processing of CPU-bound and network-bound workloads on Xen Virtual Machine Monitor (VMM). Based on our study, we conclude five key findings that are critical for cloud service providers and consumers. First, co-locating network-intensive workloads in isolated VMs incurs high overheads for extensive context switches and events in Dom0 and VMM. Second, co-locating CPU-intensive workloads in isolated VMs incurs CPU contention due to fast I/O processing in I/O channel. Third, running CPU-intensive and network-intensive workloads in conjunction delivers higher aggregate performance. Fourth, performance of network-intensive workload is insensitive to CPU assignment among VMs, whereas adaptive CPU assignment is critical to CPU-intensive workload. Last, limitation on grant table is a potential bottleneck in the current Xen system. http://doi.ieeecomputersociety.org/10.1109/TSC.2012.2 http://doi.ieeecomputersociety.org/10.1109/TSC.2011.60 How to rationally allocate the limited advertising budget is a critical issue in sponsored search auctions. There are plenty of uncertainties in the mapping from the budget into the advertising performance. This paper presented some preliminary efforts to deal with uncertainties in search marketing environments, following principles of a hierarchical budget optimization framework (BOF). We proposed a stochastic, risk-constrained budget strategy, by considering a random factor of clicks per unit cost to capture a kind of uncertainty at the campaign level. Uncertainties of random factors at the campaign level lead to risk at the market/system level. We also proved its theoretical soundness through analyzing some desirable properties. Some computational experiments were made to evaluate our proposed budget strategy with real-word data collected from reports and logs of search advertising campaigns. Experimental results illustrated that our strategy outperforms two baseline strategies. We also noticed that, (1) the risk tolerance has great influences on the determination of optimal budget solutions; (2) the higher risk tolerance leads to more expected revenues. http://doi.ieeecomputersociety.org/10.1109/TSC.2011.60 http://doi.ieeecomputersociety.org/10.1109/TSC.2011.58 Online Social networks have provided the foundation for some new applications in recent years, e.g., for the recommendation of service providers or services. In these applications, trust is one of the most important indications for consumers' decision making that requires the evaluation of the trustworthiness of a service provider along the social trust paths from a service consumer to the service provider. However, there are usually many social trust paths. Also, some social information, e.g., social relationships and recommendation roles of participants, has significant influence on trust evaluation and should be considered. In this paper, we first present a novel complex social network structure incorporating trust and important social information. We also present a new concept, Quality of Trust (QoT), and model the optimal social trust path selection with multiple end-to-end QoT constraints as an NP-Complete Multi-Constrained Optimal Path (MCOP) selection problem. Towards solving this challenging problem, we propose a novel Multiple Foreseen Path Based Heuristic algorithm MFPB-HOSTP. The results of our experiments conducted on a real dataset of online social networks illustrate that MFPB-HOSTP can efficiently identify the social trust paths with better quality than our previously proposed H_OSTP algorithm that outperforms prior algorithms for the MCOP selection problem. http://doi.ieeecomputersociety.org/10.1109/TSC.2011.58 http://www.computer.org/portal/site/tsc/ IEEE Transactions on Services Computing http://www.computer.org/portal/site/tsc/