Web Service System Research Articles

Rough Set-Based Debugging for Web Services System

Web services technology provides a flexible and cost-effective paradigm to construct highly dynamic systems through service discovery, composition, and ultra-late binding. However, its new features bring great pressure to maintain Web service-based system. Based on the massive testing results, how to locate the fault points in system is a challenging task. In the paper, a two level diagnosis framework for Web services system is proposed. In service unit level, the WSDL interface information is used to construct decision table. In service composition level, the decision information system is built by comprehensively using process specifications and interface information. Then, rule mining algorithm in rough set reasoning is adopted to reveal the input cases associated with service or system failures. How to utilize such rules to locate faults in Web services system is also discussed. In addition, two cases are introduced to validate the feasibility and effectiveness of our approach.

Design of Department Curriculum Manangement System based on Ontology

Currently, basic simple search techniques for curriculum are being implemented. But curriculum information retrieval applying ontology technologies is still weak level. In this paper, the curriculum of university was divided into the liberal arts and majors, and we proposed frame model by these methodes and designed management system to construct ontology. This management system was composed of ontology input system and ontology web service system. Ontology input system constructed curriculum of department into ontology by administrator and we designed web service system to retrieve curriculum by students. We validated ontology designed for curriculum using ontology tool.

Towards conceptual foundations for service-oriented requirements engineering: bridging requirements and services ontologies

The engineering of a service-oriented system requires the specification of functions that Web services (WSs) should provide, before WSs are built or selected. Written in a service description language, the service specification instantiates concepts different than those used for requirement engineering (RE): the former speaks in terms of operations, metrics and bindings, whereas the latter manipulates, goals, evaluations and domain assumptions. It is, however, clear that functions expected of WSs to select or build will be relevant to the stakeholders if they satisfy the stakeholders' requirements. As a result, there is a gap between the two specifications which must be bridged in order to ensure that the WS system is adequate w.r.t. requirements. This study proposes mappings between the concepts of requirements ontology and those of service taxonomy induced by the WSLD and the WSLA languages. A working prototype is presented that implements the mappings and is used to translate the instances of RE concepts into instances of WSLD and WSLA concepts. The mappings and the prototype facilitate the engineering of WS systems, as fragments of WS descriptions can be generated from requirements as a first specification of a service request.

Web Monitoring System and Gateway for Serial Communication PLC

An industrial process requires interacting with the rest of the plant, being able to exchange data with other devices and monitoring systems in order to optimize production, reporting information and providing control capabilities to distant users. Internet, and, especially web browsers are an excellent tool to provide information for remote users, allowing not only monitoring but also controlling the industrial process as an SCADA software or HMI system. The proposed system does not need specific proprietary software and its associated license costs. In this work, a webserver system is implemented under a Freescale microcontroller, acting as a gateway for a simple PLC with single RS232 communication capabilities. The webserver is modular, providing independent access to single I/O PLC locations. Different webpage design can offer different monitoring capabilities by combining the required I/O modules according to the required application without any change in the microcontroller programming. This capability is close to SCADA software or industrial HMI systems where custom screens can be made. This proposal offers a low cost and flexible monitoring solution to old or basic industrial processes controlled by PLC with low communication capabilities. Using a web browser, the system can be monitored from any internet capable device: PC, tablet, smartphone, etc. An example for a pneumatic PID levitation control system is given.

Formal Description of Services Interfaces of SMALServices in Services Computing Environment

In this paper, we describe U-S and S-S variants of interactions for services defined for SMAL organization which are described using the web services ontologies. We identify that just by defining ontologies for U-S interfaces will not suffice for the system, rather we require a state-of-the-art ontologies for S-S interfaces too. The services ontologies are defined using WSML which is a standard defined by Web Services Modeling Ontologies (WSMO). The policy-based access control framework requirement of the system presented can be accomplished by deploying either XACML or SAML, or some other rule-based implementation of access control framework which has been defined as the future scope of our work.Further, by describing and identifying the problem, we move onto the later phases, i.e., formal specification, verification, and development for evaluating the system on defined parameters. Index Terms—Semantic computing, semantic web services, communication (U-S) and service-service (S-S) communication. In this paper, we intend to describe a web-services system using ontologies and also identify two kinds of communications between the services, viz., user-service communication (U-S) interface; and service-service communication (S-S) interface. The U-S interface is obvious and is mostly observed when any user communicates or instructs a web-service. The command instructed by the user is generally given as set of parameters to the web-service from the front-end interface of the web-service. However, in case of an S-S interface, a web-service invokes another web-service with the same parameters or a subset of parameters; which can be observed as a case of delegation. We focus on both the kinds of communications and describing ontologies for both U-S and S-S communications. Specifying a U-S communication is obvious, but, specifying ontology for S-S kind-of communication would make the service intelligent enough to understand policies. In this paper, we intend to achieve an ontology description and formal methodology for the specification of web-services system which will later be used for other phases of state-of-the-art access control implementation for defining the system. Section II describes the problem, which is the service interaction of the SMAL organization. The services interactions of SMAL organization evolve in the Section II of the paper only. Section III discusses the ontology modeling for developing ontologies of the system proposed. Along with modeling ontologies, we also model the services and services interactions required at the SMAL-end to identify various U-S and S-S interactions in the system. And finally, Section IV presents the conclusions and future work. II. MOTIVATION AND PROBLEM DESCRIPTION

Performance Study of a Distributed Web Server: An Analytical Approach

With the rapid expansion of the Internet, Web servers have played a major role in accessing the enormous mass of Web pages to find the information needed by the user. Despite the exponential growth of the WWW, a very negligible amount of research has been conducted in Web server performance analysis with a view to improve the time a Web server takes to connect, receive, and analyze a request sent by the client and then sending the answer back to client. In this paper, we propose a multi-layer analytical approach to study the web server performance. A simple client-server model is used to represent the WWW server in order to demonstrate how to apply the proposed approach. We developed a systematic, analytical methodology to quantify the communication delay and queuing overhead in a distributed web server system. The approach uses the Computation Structure Model to derive server processing time required to process a request sent from a client and queueing model to analyze the communication between the clients and the server.

Improving the Automatic Derivation of Choreography-conforming Web Services Systems

We present DIEGO 2.0, a new version of our tool DIEGO. Given a WS-CDL choreography, it automatically ex-tracts a set of WS-BPEL web services such that, if these services interact with each other, they necessarily produce the behavior defined in the choreography even if the natural projection does not work. This is achieved by introducing some control messages which make services coordinate as expected. The main improvement with respect to the pre-vious version of the tool is that the number of these messages has been dramatically reduced. We formally define the new derivation, prove its correctness, and empirically compare the efficiency of new and former derivation algorithms. We also introduce other improvements of the new tool version, such as the testing engine.

Load Balancing in the Parallel Queueing Web Server System

With the explosive use of internet, contemporary web servers are susceptible to overloads during which their services deteriorate drastically and often lead to denial of services. Many companies are trying to address this problem using multiple web servers with a front-end load balancer. Load balancing has been found to provide an effective and scalable way of managing the ever-increasing web traffic. Load balancing is one of the central problems that have to be solved in parallel queueing web server system. To analyze load balancing this paper presents a queueing system that has two web servers. Firstly the centralized load balancing system is considered. The next, two routing policies are studied, the average response time and the rejection rate are derived. Finally some of our results are further considered.

A centralized and a decentralized method to automatically derive choreography-conforming web service systems

We present a formal model to represent orchestrations and choreographies and we define several conformance semantic relations allowing to detect whether a set of orchestration models, representing some web services, leads to the overall communications described in a choreography. Given this formal model, we develop automatic methods to derive a set of web services from a given choreography, in such a way that the system consisting of these services necessarily conforms to the choreography. These methods enable the construction of conforming systems of services even in cases where projecting the choreography into each service would lead to a non-conforming system. This issue is addressed by adding some control messages that make services interact as required by the choreography. Two different derivation methods are presented. In the centralized method, a new service is responsible of managing these additional control messages. In the decentralized method, the responsibility of handling these messages is distributed among all services.

Web Service System for Cultivation Test Data in Protected Horticulture

Web Service System for Cultivation Test Data in Protected Horticulture

Consideration for employing a Web services system

The main implementation in a Web services system is enterprise application integration (EAI), which has been presented for years. The emergence of Web services technology has opened up several new and previously unimaginable ways to achieve similar results. It has become a lingua franca for integrating business-to-business (B2B) applications across corporate boundaries to build a true and federated environment. Enterprises with legacy systems that migrate to use Web services may meet some problems with system integration because there is no experienced implementation guideline. Thus, the environmental factor study is important to the Web services system implementation among enterprises. This research proposes an approach for providing key factors for the enterprises to implement Web services systems. It adopts the Delphi method to scheme the appropriate Web services system implementation with some conditions in planning, development, and operation phases. The deployment circumstances are also analyzed in corporate internal and external scenarios in studies of cases. The conclusion provides the key environmental factors for enterprises to adopt Web services successfully.

A Stochastic Breakdown Model for an Unreliable Web Server System and an Optimal Admission Control Policy

Web servers have to be protected against overload since overload can lead to a server breakdown, which in turn causes high response times and low throughput. In this paper, a stochastic model for breakdowns of server systems due to overload is proposed and an admission control policy which protects Web servers by controlling the amount and rate of work entering the system is studied. Requests from the clients arrive at the server following a nonhomogeneous Poisson process and each requested job takes a random time to be completed. It is assumed that the breakdown rate of the server depends on the number of jobs which are currently being performed by the server. Based on the proposed model, the reliability function and the breakdown rate function of the server system are derived. Furthermore, the long-run expected number of jobs completed per unit time is derived as the efficiency measure, and the optimal admission control policy which maximizes the efficiency will be discussed.

A Stochastic Breakdown Model for an Unreliable Web Server System and an Optimal Admission Control Policy

Web servers have to be protected against overload since overload can lead to a server breakdown, which in turn causes high response times and low throughput. In this paper, a stochastic model for breakdowns of server systems due to overload is proposed and an admission control policy which protects Web servers by controlling the amount and rate of work entering the system is studied. Requests from the clients arrive at the server following a nonhomogeneous Poisson process and each requested job takes a random time to be completed. It is assumed that the breakdown rate of the server depends on the number of jobs which are currently being performed by the server. Based on the proposed model, the reliability function and the breakdown rate function of the server system are derived. Furthermore, the long-run expected number of jobs completed per unit time is derived as the efficiency measure, and the optimal admission control policy which maximizes the efficiency will be discussed.

온톨로지 학습에 의한 유사 웹 서비스 오퍼레이션 발견 방법

시맨틱 웹 서비스 기술의 성공을 보장하기 위해서는 품질 좋은 온톨로지의 사용이 필수적이다. 하지만 온톨로지 사용의 중요성에도 불구하고 현재 웹 서비스를 위한 온톨로지는 거의 존재하지 않으며 이들의 구축도 쉬운 일이 아니다. 이러한 문제는 오늘날 웹 서비스의 확산과 발전을 가로막는 큰 저해 요인이 되고 있다. 본 논문에서는 웹 서비스를 개발할 때 자동으로 생성되는 WSDL 문서만 가지고 항목 간 숨어있는 시맨틱 정보를 찾아내어 온톨로지를 자동 구축하고, 이를 이용한 유사 웹 서비스 오퍼레이션 발견 방법을 제안한다. 핵심 내용은 WSDL 입출력 항목들로부터 의미적으로 같은 개념들을 묶고, 각 항목들 간의 계층관계를 형성하여 자동적으로 시맨틱 온톨로지를 구축한다. 그리고 새로운 유사도 측정 방법을 통해 우선순위별 유사 오퍼레이션을 발견하며, 발견된 오퍼레이션들 중 가장 적합한 오퍼레이션을 선택하여 웹 서비스 조합에 직접 활용할 수 있는 웹 서비스 오퍼레이션 검색 시스템을 구현한다. To ensure the successful employment of semantic web services, it is essential that they rely on the use of high quality ontologies. However, building such ontologies is difficult and costly, thus hampering web service deployment. This study automatically builds ontologies from WSDL documents and their underlying semantics, and presents discovery methods of similar web service operations using these ontologies. The key ingredient is techniques that cluster parameters in the collection of web services into semantically meaningful concepts, and capture the hierarchical relationships between the words contained in the tag. We implement an operation retrieval system for web services. This system finds out a ranked set of similar operations using a novel similarity measurement method, and selects the most optimal operation which satisfies user's requirements. It can be directly used for the web services composition.

Expressive and Deployable Access Control in Open Web Service Applications

Traditional access control solutions, based on preliminary identification and authentication of the access requester, are not adequate for the context of open web service systems, where servers generally do not have prior knowledge of the requesters. The research community has acknowledged such a paradigm shift and several investigations have been carried out for new approaches to regulate access control in open dynamic settings. Typically based on logic, such approaches, while appealing for their expressiveness, result not applicable in practice, where simplicity, efficiency, and consistency with consolidated technology are crucial. The eXtensible Access Control Markup Language (XACML) has established itself as the emerging technological solution for controlling access in an interoperable and flexible way. Although supporting the most common policy representation mechanisms and having acquired a significant spread in the research community and the industry, XACML still suffers from some limitations which impact its ability to support actual requirements of open web-based systems. In this paper, we provide a simple and effective formalization of novel concepts that have to be supported for enforcing the new access control paradigm needed in open scenarios, toward the aim of providing an expressive solution actually deployable with today's technology. We illustrate how the concepts of our model can be deployed in the XACML standard by exploiting its extension points for the definition of new functions, and introducing a dialog management framework to enable access control interactions between web service clients and servers.

이종 온라인 게임 서버 간의 게임 캐릭터 이주를 위한 웹 서비스 시스템 설계 및 구현

온라인 게임에서 게임 플레이어를 대신하는 게임 캐릭터는 동일한 게임 내에서만 존재하며, 다른 온라인 게임으로 이주하는 것이 매우 어렵다. 또한 게임 플레이어는 자신의 게임 캐릭터의 성장에 많은 시간과 노력을 빼앗기고 있으며, 최근에는 이것이 많은 사회적 부작용을 낳고 있다. 따라서 본 논문은 이러한 문제점을 해결하기 위해서 기존 연구를 기반으로 이종 온라인 게임 서버 간의 게임 캐릭터 이주를 위한 웹 서비스 시스템을 설계 및 구현하였다. 그리고 제안된 시스템은 실험을 통하여 게임 캐릭터 이주 요소 중에서 4가지 능력치 (금전, HP:Hit Point, MP:Mana Point, 레벨)를 중심으로 검증하였다. In the online game, a game character to replace game player exists within the same game and it is very difficult to migrate to another on-line games. Also, players have taken a lot of time and effort in the character's growth. In recent years, it has raised many social side effects. Therefore, in order to solve these problems, this paper was implemented web services system based on previous studies for the migration of game character between different-type on-line game severs, and the proposed system verified through the experiment focused on 4 capability numerical value (money, HP:Hit Point, MP:Mana Point, level) between migration element of game character.

Wake on LAN Over the Internet as Web Service System on Chip

In this paper, we introduce a system on chip designed to run a particular Web service (WS) in an application-specific integrated circuit. The system has been designed devoid of processor and software and conceived as a hardware pattern for a trouble-free design of network services offered as WS in a service-oriented architecture (SOA). Therefore, the chip is not only able to act as a Simple Object Access Protocol service provider but also capable of registering the service on its own in an external broker server using the Universal Description, Discovery and Integration Standard publication protocol. This proposal has been named WS on chip, and its main goal is to implement more cost-effective and zero-management SOA network devices. To validate this approach, a prototypical device has been developed using a field-programmable gate array technology. The particular network service selected has been Wake on LAN (WoL) over the Internet, thus allowing any WS client to wake up any network node compatible with WoL technology. A full SOA scenario has also been developed to test the prototype functionalities and show the proposal validity.

Rummaging Around Workload Portrayal for Web Servers

Use of the Internet and the World Wide Web has improved swiftly over the past few years. Personals deploying Web servers crave to appreciate how their servers are being used by Internet users, how those patterns of use are changing over time, and what steps they should take to ensure adequate server response to the incoming requests today and in the future. This requires an evaluation of the requests offered to the Web server and the characteristics of the server’s response to those requests over a suitably long time interval. In this paper we present the results of a study of Web server system of http://www.lawetalnews.com for a six month period. In this duration the traffic to the website raised drastically in terms of incoming requests and outgoing bytes. We study the request and response types, and portray the traffic distribution on the basis of request size, response time, as well as some other factors. We wind up with system performance recommendations and identify future directions for our Web research.

Controller design and closed-loop stability analysis for admission control in Web service systems

AbstractIT systems have to provide to their users prescribed Quality of Service (QoS) levels, usually defined in terms of application performance, which must hold irrespectively of the significantly time-varying workload. To handle system overload issues, admission control is used as an overload protection mechanism which rejects requests under peak workload conditions in order to provide QoS guarantees to the running applications. For ensuring QoS levels at design time, the performance of such mechanisms should be a priori guaranteed. To this end, this paper proposes an appropriate controller, the closed-loop stability properties pf which are formally assessed.

A Remote Robot Control System Based on RIA and Flex Platform

A remote robot control system was introduced, which is based on RIA (Rich Internet Application) technology and Flex platform. The system is comprised of two parts, which are the robot control module and the design module for foreground Web page application. This paper introduced the functions of each sub block, as well as the design of the programs. Meanwhile, the construction of the whole Web Service system has been specifically outlined. By using Flex technology, the system realized an asynchronous communication between Web and Web Service components， so that the real-time capacity has been greatly enhanced.