• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.12
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• pp.5231-5248
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• 2016

As a service-oriented paradigm, web service composition has obtained great attention from both academia and industry, especially in the area of cloud service. Nowadays more and more web services providing the same function but different in QoS are available in cloud, so an important mission of service composition strategy is to select the optimal composition solution according to QoS. Furthermore, the selected composition solution should satisfy the service level agreement (SLA) which defines users' request for the performance of composite service, such as price and response time. A composite service is feasible only if its QoS satisfies user's request. In order to obtain composite service with the optimal QoS and avoid SLA violations simultaneously, in this paper we first propose a QoS evaluation method which takes the SLA satisfaction into account. Then we design a service selection algorithm based on our QoS evaluation method. At last, we put forward a parallel running strategy for the proposed selection algorithm. The simulation results show that our approach outperforms existing approaches in terms of solutions' optimality and feasibility. Through our running strategy, the computation time can be reduced to a large extent.

• Journal of Information Processing Systems
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• v.2 no.2
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• pp.114-123
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• 2006

We present in this paper the methodology for automatic generation of OWL-S service model ontology along with the results and issues. First, we extract information related to atomic services and their properties such as IOPE from the UML class diagram, and retrieve information related to the composition of services from the UML state-chart diagram. Then, the XSLT applications utilize the acquired information to generate the OWL-S service model ontology through the predefined mappings between OWL-S constructs for composite services and UML state-chart primitives. For the justification of generated service ontology, several validation checks are performed. Our service ontology generation method is general and fully automatic, as well as effective, in that it is achieved in an environment familiar to developers, and information needed to generate service ontology is provided necessarily during service development. It is also noticeable to facilitate representing the condition with GUI rather than a complex language such as OCL.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11b
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• pp.13-15
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• 2005

웹 서비스는 서비스 지향 컴퓨팅 환경으로의 변화를 주도하는 기술로써 많은 각광을 받고 있다. 본 논문에서는 사용자가요구하는 품질의 서비스를 선택할 수 있는 방법을 제안한다. 제안된 방법은 워크플로우를 분할하는 휴리스틱에 기반하여 기존의 LP(Linear Programming) 기반의 서비스 선택 알고리즘의 수행시간을 단축한다.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10b
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• pp.98-103
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• 2007

복합 웹 서비스에 대한 요청이 증가하고 있지만 유비쿼터스 환경에서 일반 사용자들이 쉽게 복합 웹 서비스를 사용할 수 있는 환경은 마련되지 않고 있다. 본 논문에서는 자연어 기반의 사용자 친화적인 인터페이스를 개발하여 이를 통해 웹 서비스나 해당 서비스 도메인 영역에 대해 지식이 전혀 없는 일반 사용자가 쉽게 자신의 요구사항을 표현하고, 사용자의 표현을 효율적으로 분석하여 복합 웹 서비스를 자동 구성하는 시스템을 제안한다. 특히 복수 문장으로 구성된 복잡한 자연어 요청으로부터 정교한 수준의 추상 워크플로우를 추출하는 방법을 제안한다.

• Steel and Composite Structures
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• v.6 no.6
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• pp.459-477
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• 2006

A theoretical research project is undertaken to develop integrated analysis and design tools for long span composite beams in modern high-rise buildings, and it aims to develop non-linear finite element models for practical design of composite beams. As the first paper in the series, this paper presents the development study as well as the calibration exercise of the proposed finite element models for simply supported composite beams. Other practical issues such as continuous composite beams, the provision of web openings for passage of building services, the partial continuity offered by the connections to columns as well as the behaviour of both unprotected and protected composite beams under fires will be reported separately. In this paper, details of the finite elements and the material models for both steel and reinforced concrete are first described, and finite element studies of composite beams with full details of test data are then presented. It should be noted that in the proposed finite element models, both steel beams and concrete slabs are modelled with two dimensional plane stress elements whose widths are assigned to be equal to the widths of concrete flanges, and the flange widths and the web thicknesses of steel beams as appropriate. Moreover, each shear connector is modelled with one horizontal spring and one vertical spring to simulate its longitudinal shear and pull-out actions based on measured load-slippage curves of push-out tests of shear connectors. The numerical results are then carefully analyzed and compared with the corresponding test results in terms of load mid-span deflection curves as well as load end-slippage curves. Other deformation characteristics of the composite beams such as stress and strain distributions across the composite cross-sections as well as distributions of shear forces and slippages in shear connectors along the beam spans are also examined in details. It is shown that the numerical results of the composite beams compare well with the test data in terms of various load-deformation characteristics along the entire deformation ranges. Hence, the proposed analysis and design tools are considered to be simple and yet effective for composite beams with practical geometrical dimensions and arrangements. Structural engineers are strongly encouraged to employ the models in their practical work to exploit the full advantages offered by composite construction.

• Journal of KIISE:Software and Applications
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• v.36 no.10
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• pp.800-815
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• 2009

Recently, Web services based service-oriented architecture is widely used to integrate effectively various applications distributed on the networks. In the service-oriented architecture BPEL as a standard modeling language for the business processes provides the way to integrate various services provided by applications. Over the past few years, some types of studies have been made on testing compatibility of services and on discriminating and tracing of the business processes in the services composition. Now a lot of studies about the services composition with BPEL are going on. However there were few efforts to solve the problems caused by the services composition. Especially, there is no effort to evaluate whether a composite service is reliable and whether it is robust against to exceptional situations. In this paper, we suggest a test framework and a testing method for robustness of the composite service written in WS-BPEL. For this, firstly we extract some information from the BPEL process and the participant services. Next, with the extracted information we construct the virtual testing environment that generates various faults and exceptional cases which may be raised within the real services. Finally the testing work for robustness of a composite service is performed on the test framework.

• Journal of Intelligence and Information Systems
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• v.18 no.3
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• pp.35-51
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• 2012

Cloud computing is internet-based computing where computing resources are offered over the Internet as scalable and on-demand services. In particular, in case a number of various cloud services emerge in accordance with development of internet and mobile technology, to select and provide services with which service users satisfy is one of the important issues. Most of previous works show the limitation in the degree of user satisfaction because they are based on so called concept similarity in relation to user requirements or are lack of versatility of user preferences. This paper presents cloud service selection reasoning which can be applied to the general cloud service environments including a variety of computing resource services, not limited to web services. In relation to the service environments, there are two kinds of services: atomic service and composite service. An atomic service consists of service attributes which represent the characteristics of service such as functionality, performance, or specification. A composite service can be created by composition of atomic services and other composite services. Therefore, a composite service inherits attributes of component services. On the other hand, the main participants in providing with cloud services are service users, service suppliers, and service operators. Service suppliers can register services autonomously or in accordance with the strategic collaboration with service operators. Service users submit request queries including service name and requirements to the service management system. The service management system consists of a query processor for processing user queries, a registration manager for service registration, and a selection engine for service selection reasoning. In order to enhance the degree of user satisfaction, our reasoning stands on basis of the degree of conformance to user requirements of service attributes in terms of functionality, performance, and specification of service attributes, instead of concept similarity as in ontology-based reasoning. For this we introduce so called a service attribute graph (SAG) which is generated by considering the inclusion relationship among instances of a service attribute from several perspectives like functionality, performance, and specification. Hence, SAG is a directed graph which shows the inclusion relationships among attribute instances. Since the degree of conformance is very close to the inclusion relationship, we can say the acceptability of services depends on the closeness of inclusion relationship among corresponding attribute instances. That is, the high closeness implies the high acceptability because the degree of closeness reflects the degree of conformance among attributes instances. The degree of closeness is proportional to the path length between two vertex in SAG. The shorter path length means more close inclusion relationship than longer path length, which implies the higher degree of conformance. In addition to acceptability, in this paper, other user preferences such as priority for attributes and mandatary options are reflected for the variety of user requirements. Furthermore, to consider various types of attribute like character, number, and boolean also helps to support the variety of user requirements. Finally, according to service value to price cloud services are rated and recommended to users. One of the significances of this paper is the first try to present a graph-based selection reasoning unlike other works, while considering various user preferences in relation with service attributes.

• Journal of Internet Computing and Services
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• v.4 no.1
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• pp.67-74
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• 2003

According to change of software development technique as design pattern, component based development etc.., web server development part is applied activity to fit in various user requirement. Especially, EJB as sewer side component model much researches and introduce by easy and various development support. Also, component composing techniques is receiving many interests by easy and efficient application way that architecture based C2 style architecture with message handling. But, in case of EJB component that can not cail thread, C2 framework modification is unavoidable for component composition by C2 style architeccture. For this, we propose techniques to use Adapter pattern to be one of structure pattern among pattern. That is, did so that component composition by C2 style architecture may can consist changing to be able to call thread function in EJB by Adapter pattern.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.8
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• pp.2030-2052
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• 2023

Analysis of a bipartite (two-mode) network is a significant research area to understand the formation of social communities, economic systems, drug side effect topology, etc. in complex information systems. Most of the previous works talk about a projection-based model or latent feature model, which predicts the link based on singular similarity. The projection-based models suffer from the loss of structural information in the projected network and the latent feature is hardly present. This work proposes a novel method for link prediction in the bipartite network based on an ensemble of composite similarities, overcoming the issues of model-based and latent feature models. The proposed method analyzes the structure, neighborhood nodes as well as latent attributes between the nodes to predict the link in the network. To illustrate the proposed method, experiments are performed with five real-world data sets and compared with various state-of-art link prediction methods and it is inferred that this method outperforms with ~3% to ~9% higher using area under the precision-recall curve (AUC-PR) measure. This work holds great significance in the study of biological networks, e-commerce networks, complex web-based systems, networks of drug binding, enzyme protein, and other related networks in understanding the formation of such complex networks. Further, this study helps in link prediction and its usability for different purposes ranging from building intelligent systems to providing services in big data and web-based systems.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06c
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• pp.7-9
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• 2006

본 논문은 워크플로우 분할에 기반하여 복합 웹 서비스를 빠르게 선택하는 방법을 제안한다. 제안된 방법은 QoS 요구사항의 제약정도 계산, 워크플로우 분할, QoS 요구사항 분해, 그리고 서비스 선택의 네 단계로 구성된다. 특히 QoS 요구사항의 분해과정이 휴리스틱에 기반하기 때문에 워크플로우 분할 시 QoS 요구사항을 만족하는 서비스를 찾지 못할 가능성이 있다. 제안된 방법은 분할에 따른 서비스 선택 실패를 줄이기 위해 주어진 QoS 요구사항의 제약정도를 계산하여 워크플로우의 분할 여부를 판단한다. 실험 결과 제안된 방법은 분할 속도, 성공률, 품질 면에서 우수한 성능을 보였다.