• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.3B
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• pp.105-113
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• 2005

In this paper, through the implementation of the application service, we evaluated the feasibility and availability of the staged application service platform, which is based on the sharing of the PVM cluster. Application service platform provides three managers for dividing the request processing steps into two stages, such as a request processing stage and a service providing stage. Three managers and its relation to the divided stages are as follows, service manager and load manager to distribute the request in front-end server for a request processing stage, job manager in clustered(back-end) servers for a service providing stage. The experiment shows that the staged application service platform provides more stable and scalable characteristics and better performance improvement on the dynamic load changes than the single server system. And also it shows that real application service system can be implemented easily without modification of the proposed service platform.

• Journal of Information Technology Services
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• v.6 no.3
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• pp.87-110
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• 2007

Recently, researches on IT Service Management (ITSM) for improving information system operation service and information system outsourcing cost estimation model are proliferating. This study suggests a new cost model of IT operation service and optimizing method based upon the characteristics of operation service as a long-term and continuous business service for both user's and service provider's point of view. This study explains the cost optimization model of IT operation service by improving service request management process, such as adequate reception and control, proper valuation, process management using project management methodology, effective organization and time management of service personnel. Especially in this study, service ability improvement effect and fixed operation cost reduction effect are defined to prove the proposed new cost model.

• Journal of Internet Computing and Services
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• v.3 no.6
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• pp.1-11
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• 2002

The purpose of this paper is the design and implementation of asynchronous remote procedure call (RPC) resource service system using the XML technology. For this purpose, the request information of client is encoded into XML document based on XML-DOM and transferred to server, Server classifies the client requests into general application program and XML-RPC service using the object which can deal with the XML-DOM. In addition, server saves the request result of client in XML-DOM structure not transmitting it immediately in order to support asynchronous service, and makes the client request redirected to another request server in XML-DOM information. As a result, general RPC and XML-RPC services were attained and client request was redirected to servers, and the execution environment was simplified compared to common RPC.

• Journal of KIISE:Computing Practices and Letters
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• v.12 no.3
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• pp.149-159
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• 2006

To provide on-demand video streaming services through the network, video objects with both high and low client request rates should be served efficiently. In this paper, we propose a dynamic on-demand streaming approach for providing services efficiently regardless of the client request rate. This approach can maintain QoS by transitioning the service scheme according to the request rate. The server provides services by the Heuristic broadcasting approach when the client request rate is low and by Striping broadcast, one of many Periodic broadcast approaches, when the client request rate is high. The server knows the variations of client request rates by the number of service channels and decides the transition to more efficient service schemes on its own. We simulated this scheme transition with various client request intervals and traces from a company providing streaming services. The results show that the performance of our approach is reasonable.

• Journal of Digital Convergence
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• v.14 no.6
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• pp.151-156
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• 2016

The purpose of this study is to find out key factors(specialized knowledge, manner, interaction) of real estate brokerage service quality derived from previous researches and to identify degrees of relations among the key factors and request intention. To do this, first of all, this study makes surveys including variables of estate brokerage service quality, credibility, and request intention. Second, it collects the data from respondents who have visited real estate brokerage firms. Finally, the data are analyzed by applying an exploratory factor analysis and a confirmatory factor analysis which is based on a structural equation modeling. The result of these surveys describes that only the interaction affects the credibility positively and the credibility has positive effects on the request intention. At the same time, the interaction impacts on the request intention directly. Therefore, these analysis results suggest that managers of real estate brokerage firm focus on the interaction of the real estate brokerage service quality factors in order to improve the customers' request intention.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.57-60
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• 2003

IEEE 802.16 Wireless MAN standard specifies the air interface of fixed point-to-multipoint broadband wireless access systems providing multiple service. Among the service classes supported by the wireless MAN, the BE class is ranked on the lowest position in priority and is usually deployed by multicast and broadcast polling MAC scheme. In provisioning such BE service, the delay performance is influenced by a number of components including restrictions on resource request per SS, the number of request opportunities in upward frame, scheduling requests at BS, and contention resolution method. As candidate components of MAC function for BE service, we propose single and multiple request schemes (for controling the number of requests per SS), exhaustive and limited request schemes (for regulating the amount of grant per request) and FCFS, H-SMF, pure SMF, SS-wise Round Robin, and pure Round Robin (for scheduling requests at BS). Then, we construct MAC schemes by combining the above components and evaluate the delay performance exhibited by each MAC scheme using a simulation method. From numerical results, we investigate the effect of MAC components on average delay and delay variation and observe the dissonance on collision reduction in a resource - limited environment.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.10
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• pp.1248-1257
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• 1999

MDDS는 디스크 시스템의 성능을 향상시키기 위해 하이퍼큐브의 각 노드에 디스크 블록들을 분산 저장하며, 인접한 노드에서 분산 저장하고 있는 디스크 블록을 중복 저장하고 있는 디스크 시스템이다. 본 논문에서는 디스크 서비스 시간을 분석하기 위한 선행 연구로서 소스 노드에서 생성된 디스크 서비스 요구 메시지가 디스크 서비스를 제공하는 목적 노드에 수신될 때까지의 시간인 전송 시간을 분석한다. 이러한 메시지의 전송 시간을 분석하기 위해 이 메시지가 링크를 통해 전송되지 못하고 대기할 확률인 전송 대기 확률을 분석한다. 이들 메시지의 전송 대기 확률을 분석하기 위해 메시지가 각 링크에서 전송되지 못하고 대기해야 하는 시간인 전송 대기 시간을 분석한다. 또 디스크 서비스 요구 메시지의 전송을 위해 링크가 사용되는 비를 분석하며, 메시지의 전송 대기 확률, 전송 대기 시간, 메시지 전송을 위해 링크가 사용될 비를 이용하여 디스크 서비스 요구 메시지의 전송 시간을 분석한다. Abstract Mirrored Declustering Disk System(MDDS) is the disk system to enhance the performance of disk system for hypercube. In MDDS, each node stores the disk blocks using the declustering technique. And the node also duplicates the disk blocks stored in neighboring nodes. In this paper, as the leading research for analyzing the disk service time, we analyze the transmission time of the disk service request message from the source node to the destination node. To analyze the transmission time of disk service request message, we analyze the probability of blocking the message related to the disk service request. For the analysis of the blocking probability, we analyze the blocking time at the link. We also analyze the rate at which the transmission link is used for transferring the disk service requests. And we analyze the transmission time of disk service request message by using the blocking probability, the blocking time, and the usage rate of link for transmitting the message.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.1-6
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• 2014

This paper proposes a mobile content curation service to collect various online/offline publications. The company publishes one-time topic information to a broker server in advance and customer curates topic information on a mobile device by requesting it. The main characteristics of the proposed service are: it is based on request/response model rather than existing publish/subscribe model, can easily specify topic information by input string without QR code or audio recognition, and retrieves all of topic information anywhere anytime by storing it on mobile device. This service can be used for second screen campaign for TV and various online/offline events.

• Journal of the Korean Society for Library and Information Science
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• v.32 no.1
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• pp.7-26
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• 1998

In this study, an ILL request system was implemented using Z39.50 item order extended service. ILL requests in this system are initiated by users through a gateway acting as a Z39.50 origin for searching remote catalog databases. When users initiate a request while searching OPACs of other libraries, an extended service request PDU for item order is first sent to the home library which subsequently generates an ILL protocol message to be sent to the target library. This approach enables users to request an item online while searching. and at the same time allows the home library to retain control over the ILL transaction.

• Journal of Korea Multimedia Society
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• v.6 no.6
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• pp.1100-1110
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• 2003

Design and implementation of remote procedure cail (RPC) resource service system based on the XML considering the request delegation between the servers are described for the resource application and efficient processing of distributed environment. For this purpose, the request information about several server, which would be used by client, is encoded into XML document based on XML-DOM and transferred to server. Server classifies the client requests using objects which can deal with the XMLL-DOM. For the request delegation between the servers, server saves the request result of client in XMLL-DOM structure without replying it immediately, and makes the client request delegated to another server in XML-DOM's request information. In addition, the resource repository are managed for resource transparency of distributed environment. As a result, resource application and processing efficiency are improved by reduction of response time caused by integration of RPC and XML-RPC services and request delegation between the servers. Extension of asynchronous and average blocking time of client were reduced and information of resource which can be used by client was offered.