• Journal of Korea Multimedia Society
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• v.11 no.9
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• pp.1310-1323
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• 2008

Recently, many studies on automated generation of composite Web services have been done. Most of these works compose Web services by chaining their inputs and outputs, but do not consider the functional semantics. Therefore, they may construct unsatisfied composite services against users' intention. Futhermore, they have high time-complexity since every possible combinations of available services should be considered. To resolve these problems, this paper proposes a sophisticated composition method that explicitly specifies and uses the functional semantics of Web services. Specifically, A graph model is constructed to represent the functional semantics of Web services as well as the dependency among inputs and outputs. On the graph, we search core services which provide the requested function ality and additional services which transform between I/O types of the user request and the core services. Then, composite services are built from combinations of the discovered services. The proposed method improves the semantic correctness of composite services by the functional semantics of Web services, and reduces the time complexity by combinations of functionally related services.

• Asia pacific journal of information systems
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• v.13 no.2
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• pp.145-170
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• 2003

Open Decision Support System(DSS) is an automated and transparent system that is built to be shared both within and across organizations. The open DSS has been thought to be a set of decision components that are communicating through Web protocols. These characteristics intuitively invite the Web services concepts, which are currently one of the new trends in network-based business services. However, web services still are not active enough to be autonomous, and to provide for composing functionalities. These lead to the motivation on building a sophisticated web service to contain these features and to utilize web services on behalf of the user. This paper aims to propose a new concept of Meta Web Service, a web service-based open DSS. Decision modules in a dynamic and open DSS can be viewed as a web service. The Meta Web Service understands the users problem statement with ontology, performs web service discovery, web service composition, and automatically generates codes for composite web service execution. A prototype of example web service has been developed to show the feasibility of the proposed idea.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.7
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• pp.1252-1273
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• 2011

In Web Service Composition (WSC) area, services selection aims at selecting an appropriate candidate from a set of functionally-equivalent services to execute the function of each task in an abstract WSC according to their different QoS values. In despite of many related works, few of previous studies consider transactional constraints in QoS-aware WSC, which guarantee reliable execution of Composite Web Service (CWS) that is composed by a number of unpredictable web services. In this paper, we propose a novel global selection-optimal approach in WSC by considering both transactional constraints and end-to-end QoS constraints. With this approach, we firstly identify building rules and the reduction method to build layer-based Directed Acyclic Graph (DAG) model which can model transactional relationships among candidate services. As such, the problem of solving global optimal QoS utility with transactional constraints in WSC can be regarded as a problem of solving single-source shortest path in DAG. After that, we present Graph-building algorithms and an optimal selection algorithm to explain the specific execution procedures. Finally, comprehensive experiments are conducted based on a real-world web service QoS dataset. The experimental results show that our approach has better performance over other competing selection approaches on success ratio and efficiency.

• The KIPS Transactions:PartD
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• v.14D no.2
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• pp.265-272
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• 2007

In this paper, we implement an automated composition system of web services using hybrid techniques that merge the benefit of BPEL techniques, with the advantage of OWL-S, BPEL techniques have practical capabilities that fulfil the needs of the business environment such as fault handling and transaction management. However, the main shortcoming of these techniques is the static composition approach, where the service selection and flow management are done a priori and manually. In contrast, OWL-S techniques use ontologies to provide a mechanism to describe the web services functionality in machine-understandable form, making it possible to discover, and integrate web services automatically. This allows for the dynamic integration of compatible web services, possibly discovered at run time, into the composition schema. However, the development of these approaches is still in its infancy and has been largely detached from the BPEL composition effort. In this work, we describe the design of the SemanticBPEL architecture that is a hybrid system of BPEL4WS and OWL-S, and propose algorithms for web service search and integration. In particular, the SemanticBPEL has been implemented based on the open source tools. The proposed system is compared with existing BPEL systems by functional analysis. These comparisions show that our system outperforms existing systems.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.3
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• pp.1260-1281
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• 2015

As the number of services available on the Web increases, it is vital to be able to identify which services can be trusted. Since there can be an extremely large number of potential services that offer similar functionality, it is challenging to select the right ones. Service requestors have to decide which services closelysatisfy their needs, and theymust worry about the reliability of the service provider. Although an individual service can be trusted, a composed service is not guaranteed to be trustworthy. In this paper, we present a trust model that supports service discovery and composition based on trustworthiness. We define a method to evaluate trust in order to discover trustworthy services. We also provide a method to perform trust estimation for dynamic service composition, and we present results of two experiments. The proposed model allows for service requestors to obtain the most trustworthy services possible. Our mechanism uses direct and indirect user experience to discover the trustworthiness of the services and service providers. Moreover, composing services based on quantitative trust measurements will allow for consumers to acquire a highly reliable service that meet their quality and functional requirements.

• The KIPS Transactions:PartB
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• v.11B no.4
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• pp.457-464
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• 2004

The Web Services descriptions such as DAML-S/OWL-S, BPEL4WS and WSMF focusing on the functional aspects of Web Services have limitations for the representation of the conceptual and semantic capabilities of Web Services, although WSMF is based on ontology and can represent the goal of Web Services. This paper proposes the new description formalism based on the competence ontology that can represent both functional and semantic aspects of Web Services. This paper also presents the integration and the composition of Web Services by means of Data Mediator(D-Mediator) and Control Mediator(C-Mediator) to mediate compositional in compatibility between heterogeneous Web Services.

• Proceedings of the Korea Society for Simulation Conference
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• 2005.05a
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• pp.50-55
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• 2005

웹 서비스와 웹 프로세스(Web Processes)는 다양한 시스템 상에서 이종의 소프트웨어 컴포넌트들을 효과적으로 통합할 수 있는 기술이다. 웹 서비스의 활용이 증대함에 따라 성능(performance), 비용(cost) 등 005(Quality of Service)는 서비스 제공자들 간의 차별화를 위한 요건으로 그 중요성이 증가하고 있다. 본 논문에서는 웹 서비스 성능 분석 도구인 sPAC(Web Service Performance Analysis Center)을 소개하여, 웹 서비스 조합시 성능의 만족 여부를 미리 고려할 수 있음을 보인다. sPAC은 1) 그래픽 기반 웹 프로세스 구성 환경을 제공, 2) 경부하(light load) 조건에서의 성능 테스트를 위해 웹 서비스를 호출, 3) 웹 프로세스에 대한 시뮬레이션 모델을 자동 생성 하여, 과부하(heavy load) 조건에서 시뮬레이션 기반의 성능 분석 수행, 4) 웹 서비스의 성능 분석 결과와 평가 데이터의 보고서 생성을 제공한다.

• Journal of the Korea Society of Computer and Information
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• v.14 no.11
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• pp.145-157
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• 2009

OSGi enables services to be dynamically discovered through its service registry for fostering interactions among themselves, positioning itself as one of the most prominent SOA technologies. Web Services also provide a mature technical base of open business services being employed over the Internet and allow more value-added applications to be built up from component services. In this paper, we propose a new architecture, built on the concept of dynamic service binding, to support interbred service compositions of OSGi and Web Services. Web Services are imported into OSGi domains, and the compositions are described in WS-BPEL language. The support for crossbred compositions of OSGi services and Web Services opens up a new opportunity of a wider range of applications beyond their respective traditional target domains of home gateways in LAN environments and business applications in global Internet environments.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10b
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• pp.247-249
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• 2004

그동안 planning 분야에서는 action 또는 plan이 epistemically feasible한지에 대한 Knowledge Preconditions(KP) 문제(1)를 다루기 위해 여러 연구들이 제안되었다. 하지만 기존 연구에서는 feasibility에 대한 검사를 design-time에만 수행하며 run-time에서 수행하지 않기 때문에 여러 agent의 트랜잭션들이 발생하는 웹서비스 조합(WSC : Web Services Composition)에서는 문제가 발생하게 된다. 따라서 본 논문에서는 이 문제(Interfering Agent Problem)를 해결하기 위해 transactionally feasible한 WSC를 정의하고 WSC의 atomicity를 보장하기 위한 방법을 제안한다. 뿐만 아니라 WSC를 표현하기 위해 Description Logics기반의 TL-ALCF(2)를 적용하여 시맨틱 웹의 온톨로지(OWL-S)와 성능이 좋은 기존 subsumption 프로시저를 그대로 이용할 수 있도록 한다.

• The KIPS Transactions:PartD
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• v.15D no.6
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• pp.879-888
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• 2008

As web services have become an important architecture solution, web service composition applications are developed actively. A mobile application supporting multiple services requires a complex user interface so that the interface needs to consist of more than one view and to provide a way to navigate between views. In this paper, we presented a formal way to analyze a set of views for a given service specification, and a relation model between views and methods. We then provided an algorithm to generate codes for service method calls and navigation between views. Therefore, with an optional user configuration input, we could automatically generated XForms codes from the web service specifications. Finally, we developed a proof of concept implementation of XForms browser to show that the generated codes works well as an interface for web service compositions.