Earticle

현재 국내외 빅 데이터 분석 서비스에 대한 수요가 증가하고 있다. 하지만 빅 데이터 분석 서비스의 개발은 장기간에 걸친 다양한 인력의 투입과 많은 개발 비용이 필요하다. 이에 본 논문에서는 빅 데이터를 분석하기 위한 다양한 웹 서비스들을 조합하여 손쉽게 빅 데이터 분석 서비스를 만들어내는 빅 데이터 서비스 조합 프레임워크를 제시한다. 서 비스 조합에 대한 기존의 많은 연구가 존재하지만, 프레임워크는 빅 데이터를 다루는 웹 서비스들을 조합해서 실행할 때 문제가 되는 사항들을 고려한 실행 구조를 갖는다. 그리고 이러한 구조 하에서 서비스를 조합하고 실행하기 위한 방법에 대해 설명하고, 교통 빅 데이터 분석을 위해 교통 도메인에 적용한 사례를 소개한다. 향후에는 프레임워크를 더욱 다양한 도메인에 적용하여 빅 데이터 분석 서비스 개발 비용이나 인력 문제 등을 해결할 수 있을 것이다.

In recent years, demand for big data analysis service is increasing in Korea and abroad. However, the development of big data service requires a substantial amount of time and human resources. In this paper, we suggest a “Big data Service Composition Framework” for the development of a new big data service that easily combines various big data services. Users can develop a big data analysis service easily through the framework. The earlier studies about service composition already exist, but the framework has specific structure to execute composite service for solving problems about adapting to big data. We present the structure and the execution method and an application of the framework in Transportation domain. In the future, we can solve problems with expenses and human resources when developing a big data service by applying the service composition framework to various domains.

Web services need to be orchestrated to achieve complex demand. However, existing approaches on Web service composition are mainly based on syntax match. It is very difficult to compose heterogeneous Web services with syntax in accord with function. Gradually, Petri net becomes a powerful system modeling and analysis tools research discrete event dynamic system. In order to solve this problem, we present a method to compose Web services automatically based on generalized stochastic Petri nets. Firstly, the generalized stochastic Petri nets (GSPN) and OWL-S composition process are used to model the automatic composition process, and then the Web service composition is realized. Finally, the feasibility of this method is demonstrated though the analyses of a case study with a booking service system. Compared with the existing methods of Web service composition, this method can describe Web service automatic composition more effectively.

With the rapid development of cloud computing and service computing, Web services are combined to form the composite service with a large granularity is an important research direction at present. The current service composition methods have the problems of low composition efficiency and accuracy, this paper proposes a semantic Web service composition method based on the binary tree. This method uses the ontology semantic reasoning relationship and binary tree theory to composite Web services. The composition relations between Web service interfaces are mainly considered. The approach can enhance the efficiency and accuracy of service composition, and the experiments are used to validate and analyze the proposed methods.

In recent years, the Web service composition technology has developed rapidly, as a result, the energy consumption problem is also increasingly prominent. Faced with this situation, the paper firstly gives out the power model of single service; then derives the model of service composition according to its characteristics, and gives out the corresponding QoS constraints at the same time. After finishing the model, the paper talks about the allocation of feasible path, which is one of the problem in model calculation. The author introduces a graph-plan based searching algorithm, and uses the concept of hierarchical search to solve the problem. At last, the experimental results show that compared with traditional methods, the approach in this paper can not only satisfy the user requests with QoS restricted, but also reduce the energy consumption of service composition effectively.

Automatic composition of Web services is a challenging task as independently developed Web services are not always compatible with each other. In order to resolve the heterogeneity between Web services and improve the quality of Web service composition, we propose a new approach based on semantics for Web service composition, which widely deploys Petri Nets and ontology. This paper proposes a framework for semantic Web service composition that builds Petri net model of interactions between Web services and builds ontology representing domain knowledge, then combines the Petri net models with ontology-based mediation.

The privacy protection model under Web service composition framework is studied in depth, then the privacy of customers can be protected effectively. Firstly, the basic framework of Web service composition is studied; Secondly, the managing method of service publication is analyzed; Thirdly, the privacy protection model under Web service composition framework is discussed; finally the evaluation method of algorithm for privacy protection is summarized.

With widely used at present, web service can enhance not only the reusability of code, but also the utilization rate of the service resources shared on the web services composition. To solve the difficulty in the communication and expression of the requirement information in complex web service composition, this study proposed a visualization method to describe service composition models through animation. This method employed the requirement behavior model established by the behavioral description language as the research object. In the execution mechanism of the animation, state machine and state block were utilized as the execution model and description model respectively. Each state migration was corresponded to a behavior that calls for visualized description. The motion of figure was controlled by associating each migration in the state block model with an action primitive through an association element. The visualization of the requirement behavior model was thereby realized. The advantages of the method lie in that the requirement changes are avoided. This attributes to that the missing and incorrect potential requirements are observable for the users with different backgrounds owning to the intuition of animation. Moreover, the correctness of the requirement animation is ensured through a series of detection on the BDL model. Finally, this study empirically analyzed the method using a travel system and introduced the modeling and animation tools it realized.

Web service composition is a mature and effective way to realize the rapidly changing requirements of business in service-oriented solutions. Testing the compositions of web services is complex, due to their distributed nature and asynchronous behaviour. Control flow testing focuses on the transfer of control, while data flow testing focuses on the definitions of data and their subsequent use. The execution of a service is driven by the received and manipulated data; hence validation of data flow is very critical in composition. Colored Petri Nets (CPNs) is one model that combines data and control flow with behavioural aspects of a given business requirement. In this paper, a test framework based on a data-driven CPN model for functional testing of web service composition is proposed. The test framework also includes test design coverage measurement using three newly formulated metrics: Decision Coverage, Input Output Coverage and Implementation Coverage. The framework was applied to airline reservation system and the generated test sequences were evaluated against the coverage criteria.

Traditional web service discovery composition technology is hard to get adapted to dynamic, flexible modern business workflow. Due to the advantage of Cloud computing, dynamic, distributed, heterogeneous and autonomous nature to solve this problem provides a new way of thinking. This paper proposes a cloud computing environment that supports dynamic application service composition model, and in order to meet the real dynamic workflow environment, proposed cloud computing Web Service workflow management system CCB_WSFMS.

With the widespread proliferation of web services, the demand on highly reliable and available services increases to satisfy business and personal needs. As the number of functionally similar web service increases on the Internet, Quality of Service (QoS) based web service selection and composition has gained much attention. However, the existing architectures for runtime service composition requires discovery of all functionally similar services, which consumes too much time. Instead, it can be possible to discover only those services which are highly reliable and thus included in composition. This issue can be solved by introducing a broker based architecture for automated dynamic web service discovery and composition in which the composition operation accepts as input a set optimized services along with their QoS specifications. The proposed architecture is able to reduce the composition time by performing optimized selection of services using Local Selection and Local Optimization (LSLO) approach during service composition. The architecture is fault tolerant and ensures improved reputation prediction accuracy of selected services using Mixed Opinion based Reputation Prediction (MORP) approach. In this paper, a comparative analysis is also performed on the basis of set of criterion to analyze the existing dynamic web service discovery and composition architectures for their strengths and weaknesses.

The web service developed by telecommunication domain is ineffective since they are demonstrated by syntactic description rather than semantic. The motivation of the research is to have semantic description with existing web services, and provides discovery, composition and invocation of web services automatically. The objective is to identify the discovery and composition concerns and devise a compositional approach that covers all concerns. So a new prototype named Semantic Web Service Engine for Telecommunication which automatically discover and composite a web service was proposed, enables semantic through upper ontology and maps Web Service Description Language to Ontology Web Language-Semantic. For composition, a genetic algorithm was proposed which can solve problems with great distinctiveness. This approach automatically discovers and generates the required composite semantic web services and considers all identified concerns concurrently, improves the accuracy for the service discovery and unifies the semantic representation of telecommunications without human intervention.

최근 웹 서비스(Web Service)와 웹 프로세스(Web Process)는 이기종 시스템의 통합과 웹 애플리케이션 배포를 위한 대안으로 주목받고 있으며, 이에 따라 웹 서비스의 QoS(Quality of Services)의 중요성도 증가하고 있다. 본 논문에서는 웹 서비스의 QoS 분석 방법을 제안하고, QoS 중심의 웹 서비스 조합 도구인 SimQom4W (Simulation-based QoS-aware Composer for Web Services)를 소개한다. SimQom4W는 첫째, 웹 서비스와 웹 프로세스의 구성을 시각으로 기술하고, 둘째, 웹 프로세스에 대한 테스트 코드와 시뮬레이션 코드를 자동 생성하여 실행시킴으로써 QoS를 분석한다. 셋째, 다양한 QoS 요구사항을 만족하는 최적의 웹 프로세스를 선택할 수 있도록 하며, 넷째, 웹 서비스의 QoS 분석 및 평가 데이터의 보고서를 생성하여 제공한다.

Web services and their composition (web processes) are promising technologies to efficiently integrate disparate software components over various types of systems. As many web services are nowadays available on Internet, quality of services (QoS) and performance/cost become increasingly important to differentiating between similar service providers. In this work, we introduce sPAC (Web Services Performance Analysis Centre) and show how customers can benefit from sPAC to consider performance in composing and commercializing web services. sPAC 1) helps users to graphically describe the workflow of web services, 2) invokes web services to test out performance for light load conditions, 3) automatically converts the web services and the flow between them into a simulation model, 4) conducts extensive simulations for heavy load conditions and various usage patterns, and 5) reports analysis results and estimation data for the web services.

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.

최근 인터넷의 발달과 함께 웹을 기반으로 하는 클라이언트-서버 분산 구조의 웹서비스 시스템 구조가 점차 확산되고 있다. 게다가, 최근에는 스마트폰을 이용한 스마트폰 애플리케이션이 대중화 되면서, 웹 서비스의 활용이 점차 확대되는 추세이다. 웹을 기반으로 클라이언트와 서버 사이에 통신을 하기 위해서는 원격 프로시저를 정의한 인터페이스가 규정되어야 하며, 기존에는 W3C에서 정의한 WSDL를 사용하여 웹서비스를 기술하곤 하였다. 그러나, 이와 같은 기존의 웹서비스 기술 및 사용방법은 그 구성이 복잡하고 오버헤드가 큰 이유로 널리 활용되지 못하였다. 최근에는 스마트폰이 대중화 되면서 REST 웹서비스의 활용이 확산되는 추세다. SOAP 기반 웹서비스에 대해서는 서비스 조합에 대해서 충분히 다루어 졌으며, 어느정도 정리된 연구분야이다. SOAP 웹서비스는 기계가 인식하기 쉽도록 엄격한 규약과 인터페이스를 정의한 것이기 때문이다. 하지만, REST 웹서비스 조합 방법에 대해서는 현재까지도 충분히 연구되지 않았다. REST 웹서비스는 사람이 사용하기 편리하도록 설계된 기술이고, 그 조합에 대해서는 표준에서 관여하지 않기 때문이다. 본 논문에서는 REST 웹서비스의 기존의 소켓(socket)을 이용한 서버-클라이언트 통신 방법 대신에, REST 웹서비스를 활용하는 서버-클라이언트 스마트폰 앱개발 방법을 제안한다.

OSGi는 서비스 레지스트리를 통한 런타임 서비스 검색을 지원함으로써 서비스간의 인터랙션을 진작하는 대표적인 SOA기술이다. OSGi와 더불어 SOA의 선두 그룹을 형성하고 있는 웹 서비스 기술은 광역 인터넷에 위치한 네트워크 서비스들이 개방 인터페이스에 따라 상호 작용하여 새로운 부가 기능을 지원할 수 있도록 하는 토대를 제공하고 있다. 본 논문에서는 OSGi 프레임워크 환경에서 웹 서비스 조합 언어인 WS-BPEL을 이용하여 OSGi 서비스와 웹 서비스를 합성하여 복합 서비스 및 응용을 구성할 수 있도록 하는 새로운 기법을 제안한다. 이 결과 랜 환경을 주 대상으로 하는 OSGi 서비스와 광역 엔터프라이즈 환경의 웹 서비스가 소속 도메인 경계를 넘어 서비스 조합에 참여할 수 있게 됨으로써 단일 도메인 내 조합에서는 가능하지 않았던 응용 기능 지원이 가능해진다.

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.

시멘틱 웹 서비스의 최종적인 목표는 네트웍으로 연결된 프로그램들과 장치들이 사람의 명령 없이 긴밀하게 상호작용 하는 것이다. 시멘틱 웹은 정보의 의미를 알 수 있는 프레임워크를 연구하였는데, 이는 인공지능을 기반으로 하는 RDF. RDFS, DAML+OIL, OWL등의 언어를 기반으로 하여 연구되었다 시멘틱 웹 커뮤니티에서는 웹의 정보 뿐 아니라 서비스에도 정확한 의미를 부여하기 위해서 DAML+OIL 온톨로지 기반의 새로운 기술인 DAML-S 온톨로지 기술을 제안하였다. DAML-S는 Service. Service Profile. Service Model. Service Grounding의 4개의 상위 온톨로지로 구성되는데, 특히 Service Profile, Service Model 온톨로지와 인스턴스를 이용하여 사용자의 요구에 적합한 서비스 검색과 Composition01 가능하다. 사용자의 요구가 atomic 서비스가 아닌 여러 atomic 서비스들을 함께 이용해야 하는 경우에는 시멘틱 웹 서비스 검색 시스템 외에 추가적인 웹 서비스 Composer가 필요하게 된다. 본 논문에서는 사용자의 요구로부터 필요한 웹 서비스 chain을 구성함에 있어서 사람이 개입하지 않는 STRIPS 타입의 자동 웹 서비스 Composer를 제안한다.

시맨틱 웹서비스 조합을 위해 인공지능 분야의 계획수립 기법을 적용하려는 연구들이 최근 늘고 있다. 하지만 전통적인 계획수립 기법이 갖는 계획작성 단계와 실행 단계가 분리되어 있기 때문에 여러가지 한계성을 나타낸다. 본 논문에서는 이의 대안으로서 동적 재연결을 지원하는 반응형 계획기 기법을 사용함으로써 제기된 문제점들을 해결하고자 하였으며, 온톨로지 처리 결과를 계획수립 과정에 반영함으로써 의미 기반의 웹서비스 조합이 이루어지도록 하였다. 그리고 이를 지원하는 시스템의 개발과 응용을 통해 반응형 계획기술이 시맨틱 웹서비스의 조합과정에서 견고하고, 유연하게 동작함을 알 수 있었다.