Hai Liu

USTC-CityU Joint Advanced Research Center, Hong Kong, Hong Kong

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Publications (10)0.48 Total impact

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    ABSTRACT: Web services technologies promise to create new business applications by composing existing services and to publish these applications as services for further composition. The business logic of applications is described by abstract processes consisting of tasks which specify the required functionality. Web services provision refers to assigning concrete Web services to perform the constituent tasks of abstract processes. It describes a promising scenario where Web services are dynamically chosen and invoked according to their up-to-date functional and non-functional capabilities. It introduces many challenging problems and has therefore received much attention. In this article, the authors provide a comprehensive overview of current research efforts. The authors divide the lifecycle of Web services provision into three steps: service discovery, service selection, and service contracting. They also distinguish three types of Web services provision according to the functional relationship between services and tasks: independent provision, cooperative provision and multiple provision. Following this taxonomy, we investigate existing works in Web services provision, discuss open problems, and shed some light on potential research directions.
    IJSSOE. 01/2010; 1:26-45.
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    ABSTRACT: Web services provision is the process of assigning particular services to the constituent tasks of business processes. It describes a promising scenario where services are dynamically chosen and invoked in a business process according to their functional and non-functional capabilities. It also introduces many challenging problems and has received much attention recently. In this paper, we distinguish three types of provision: independent provision, cooperative provision and multiple provisioning. For each type, we consider three major phases, that is, service discovery, service selection and service contracting. Following this rule, we investigate existing works in web services provision and shed some light on potential research directions.
    Proceedings of the 3rd International Conference on Ubiquitous Information Management and Communication, ICUIMC 2009, Suwon, Korea, January 15-16, 2009; 01/2009
  • Hai Liu, Qing Li, Naijie Gu, An Liu
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    ABSTRACT: Currently, the natural expectation of contracting a set of Web services by virtue of their semantics is becoming more and more feasible and popular. Meanwhile, it is generally accepted that a formalism with a well-defined model-theoretic semantics (i.e. some sort of logics) should be considered as the underpinning of Semantic Web Services [1]. In this paper, concrete domain and action theory are incorporated into a very expressive DL, called ALCQO. Notably, this extension can significantly augment the expressive power for modeling and reasoning about dynamic aspects of services contracting. At the same time, the original nature and advantages of classical DLs, particularly the ability to describe "static" aspects of Web services, are also preserved to the extent possible.
    Web-Age Information Management, 2008. WAIM '08. The Ninth International Conference on; 08/2008
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    ABSTRACT: QoS-aware Web services composition has recently received much attention. While most work focused on service selection, we study QoS in another stage of the life cycle of composite services, namely, scheduling. An interesting problem is whether we can obtain better QoS via scheduling even when the component services have been fixed. In this paper, we propose an approach to find an optimal (near-optimal) schedule with the least cancellation cost, which can further improve the overall QoS of composite services. An approach to analyze the expected cancellation cost of a schedule of a composite service is proposed and QoS-Aware service scheduling is formalized as a Constraint Satisfaction Optimization Problem (CoSOP). Two algorithms - heuristic back tracking and genetic algorithm - are presented to find an optimal (near-optimal) schedule, and their performance is studied by simulations. Preliminary experimental results show that our approach is effective.
    Web-Age Information Management, 2008. WAIM '08. The Ninth International Conference on; 08/2008
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    ABSTRACT: Service composition is becoming a prevalent way to building service-oriented business applications (SOBAs). In an open service environment, the profit of composition (PoC) is a primary concern of building such applications. How to improve the PoC is a significant issue in developing SOBAs but was largely overlooked by current research. Particularly, the modeling and prediction of PoC should play a key role to drive the composition process. In this paper, we focus on how to model and predict PoC in SOBAs. We regard the PoC of a composite service as a function of the quality of service (QoS) attributes, defined in the service level agreement (SLA) between the service and its external partners. Based on the PoC prediction approach, we further propose a profit-driven composition methodology to assist enterprises to make more profit in their SOBAs.
    2008 IEEE International Conference on Web Services (ICWS 2008), September 23-26, 2008, Beijing, China; 01/2008
  • Hai Liu, Qing Li, Naijie Gu, An Liu
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    ABSTRACT: Web services composition process needs business rules to regulate the behavior of the partner services. However, designing these rules is time-consuming and error-prone, especially under the condition that current standards barely provide any abstract and high-level guidance. In this spirit, rule analysis and verification for services composition is urgently required to augment its reliability and usability. In this paper, we choose a variant of Description Logics, called ALCO(Q*), as the underlying logic, and provide a formal mapping to transform ECA rules, so that the semantics in the original ECA rules can be captured and are computationally traceable. To this end, we further investigate some important properties for business rules, namely, redundancy, termination and conflict, and propose several sound and complete algorithms to resolve them.
    2008 IEEE International Conference on Web Services (ICWS 2008), September 23-26, 2008, Beijing, China; 01/2008
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    Hai Liu, Qing Li, Naijie Gu, An Liu
    [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we incorporate concrete domain and action theory into a very expressive Description Logic (DL), called ALCQO. Notably, this extension can significantly augment the expressive power for modeling and reasoning about dynamic aspects of services contracting. Meanwhile, the original nature and advantages of classical DLs are also preserved to the extent possible.
    Proceedings of the 17th International Conference on World Wide Web, WWW 2008, Beijing, China, April 21-25, 2008; 01/2008
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    ABSTRACT: The successful execution of a composite service relies on not only its internal design and states, but also the execution of its autonomous, heterogeneous, and distributed participants. Exception handling for a composite service is facing great challenge. This paper presents a mechanism to capture external exception contexts from partners' applications through contexts enhanced Web services conversation (CeWSC), which introduces just a minimal overhead by an effective use of SOAP header and acknowledgement. Moreover, we also propose an enhanced event-driven mechanism to incorporate exception contexts into exception handling for a composite service to facilitate its flexible and reliable execution.
    E-Commerce Technology and the 4th IEEE International Conference on Enterprise Computing, E-Commerce, and E-Services, 2007. CEC/EEE 2007. The 9th IEEE International Conference on; 08/2007
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    Hai Liu, Qing Li, Naijie Gu
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    ABSTRACT: In this paper, we present a context-based mechanism to facilitate Web service discovery, which takes user preferences and dislikes into account. A novel method to quantify and evaluate contexts is proposed, which lays down a possible foundation to address such practical problems like user-centered service discovery.
    Tenth IEEE International Enterprise Distributed Object Computing Conference (EDOC 2006), 16-20 October 2006, Hong Kong, China; 01/2006
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    ABSTRACT: Composite Web services need transactional support to guarantee their consistent and reliable execution. Due to the long running and inter-organizational characteristics of Web services, current approaches for transactional Web services composition adopt compensation mechanism to maintain atomicity. A common assumption is that a compensation operation can be applied at any time with no cost. However, compensation operations are typically associated with temporal and cost constraints, which make compensation mechanism problematic in this new environment. To address this problem, we distinguish two types of scheduling for transactional Web services composition: time aware scheduling and cost aware scheduling. We devise several algorithms for scheduling, which can ensure the atomicity of composite services when compensation operations have temporal constraints, and assist composite services to maintain atomicity with minimum compensation cost when compensation operations have cost constraints. We benchmark our algorithms by simulations and the results show that our algorithm decreases the compensation cost and in turn improves the QoS of transactional services composition.
    Journal of Computer Science and Technology 24(4):638-651. · 0.48 Impact Factor

Publication Stats

31 Citations
0.48 Total Impact Points

Institutions

  • 2006–2010
    • USTC-CityU Joint Advanced Research Center
      Hong Kong, Hong Kong
  • 2009
    • City University of Hong Kong
      Chiu-lung, Kowloon City, Hong Kong
  • 2007–2008
    • University of Science and Technology of China
      • School of Computer Science and Technology
      Hefei, Anhui Sheng, China