• Journal of Information Technology Services
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• v.16 no.1
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• pp.99-118
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• 2017

Growing importance of online security on certification, many of the web-related security technology introduced day by day. Especially, using smart certificate (USIM) is recognized as one of the most safe and convenient method for the security of public certificate. The purpose of this study is to find the factors that affect the Intention of switching to smart certificate for the general public who use public certificate service. Based on migration theory, this study determined the relationship between pull factors, push factors and mooring factors which can affect the intention of switching to smart certificate. To empirically analyze the proposed hypothesis, the statistical analysis were conducted based on the response from 350 public certificate service users using SPSS 22.0 and Smart PLS 2.0. The results of this study can be summarized as follows. First, system quality, one of the pull factors has positive influence on perceived ease of use. On the other hand, the other pull factor, service quality has positive influence on both perceived ease of use and perceived usefulness. Second, push factors, user experience and information security awareness have positive influence on perceived ease of use only. Third, mooring factor, switching cost does not have influence on switching intention while perceived usefulness has positive influence on. The results of this research can be used for whom has interest to the switching intention of public certificate service for online security and provide the proper understanding about smart certificate service mechanism.

• The KIPS Transactions:PartC
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• v.15C no.4
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• pp.253-262
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• 2008

Providing Quality-of-Service (QoS) guarantee requires the reservation of resource needed to accommodate the traffic flow of service for which resource reservation protocol (RSVP) was introduced. However, if any RSVP-capable router on the path fails to accommodate the traffic flow due to lack of resource, the flow is not allowed no matter how much surplus resources other routers on the path have. In order to solve this problem, this paper proposes a resource reservation method with available resource migration between RSVP-capable routers in which the routers use the recently developed latency optimized fair queuing scheduler. The results of the simulation applying the proposed method to an evaluation network show that it may yield the gain of up to 165% compared to that in the original one in terms of the number of admitted flows.

• Journal of the Korean Geographical Society
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• v.51 no.4
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• pp.525-539
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• 2016

This study attempts to predict the changes in the spatial distribution of occupational employment in Korea by applying Markov Chain Model. For the purpose we analyze the job-related migration pattern and estimate the transition probability with the last six years job-related migration data. By applying the Chapman-Kolmogorov equation based on the transition probability, we predict the changes in the spatial distribution of occupational employment for the next ten years. The result reveals that the employment of professional jobs is predicted to increase at every city and region except Seoul, while the employment of elementary labor jobs is predicted to increase slightly in Seoul. In particular, Gangwon-do and Chuncheongdo are predicted to increase in the employment of all occupational jobs.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.12
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• pp.568-575
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• 2008

Server consolidation by sever virtualization can make one physical machine(PM) to run several virtual machines simultaneously. Although It is attractive in cost, it has complex workload behaviors. For that reason, efficient resource management method is required. Dynamic relocation of virtual machine(VM)[3,4] by live migration[1,2] is one of resource management methods. We proposed SCOA(Server Consolidation Optimizing Algorithm) : a fine-grained load balancing mechanism worked on this dynamic relocation mechanism. We could obtain accurate resource distribution information through pointed physical machines on multi dimensional resource usage coordination, so we could maintain more balanced resource state. In this paper, we show the effectiveness of our algorithm by comparison of experimental results between SCOA and sandpiper[3] by software simulation.

• Smart Media Journal
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• v.8 no.3
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• pp.41-46
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• 2019

In a MMORPG, a typical application of virtual environment systems, it is a common desire to play in a more realistic environment. However, it is very difficult to provide a latency-free virtual environment to a large user base, mainly due to the fact that the real environment must be configured on multiple servers rather than on single server and that data must be shared on the real server when users move from one region to another. Experiencing response delays continuously in the process of information synchronization between servers greatly deteriorates the degree of immersion. In order to solve this problem, it is necessary to minimize the response delay occurring in the information synchronization process between the servers. In this paper, we propose Migration Agent for efficient information synchronization between field servers providing information of virtual environment and minimizing response delay between Field Server and PC(Player Character) and implement it in cloud computing network. In the proposed system, CPU utilization of field server increased by 6 ~ 13%, and response time decreased by 5 ~ 10 seconds over the existing system in 70,000 ~ 90,000 PCs

• The Journal of the Korea Contents Association
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• v.6 no.11
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• pp.295-301
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• 2006

The scope ID field of IPv6 multicast address indicates the zone of the destination for which a multicast traffic is intended. Without any further examination on the header field, the scope ID enables a router to determine whether the traffic will be forwarded to a subnet or not. For the graceful migration from IPv4 networks to IPv6 networks, various IPv6 applications working through IPv4 networks are indispensable during the migration period. This paper describes development of an interactive remote lecture system providing service integration on voice, image, and data of teaching materials. Access right to the network for dialog among multicast group members is controlled via additional TCP (Transmission Control Protocol) session. A jitter buffer algorithm was implemented to improve the voice communication jitters.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.215-218
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• 2012

스팟 인스턴스(Spot instance)는 클라우드 환경에서 사용자가 제시한 입찰 가격으로 클라우드 내의 자원을 이용하여 작업을 수행할 수 있게 하는 새로운 방식이다. 사용자는 자신의 입찰 금액이 클라우드 내의 스팟 인스턴스 가격을 초과하는 한 인스턴스를 실행할 수 있다. 그러나 입찰 가격이 스팟 가격보다 낮다면 작업 실패가 발생하고, 이로 인해 작업 완료 시간은 지연되며 서비스 품질은 저하된다. 이 문제를 해결하기 위해, 본 논문에서는 스팟 인스턴스에서 사용자 비드가 초과되어 작업 수행이 중지된 VM에 대하여 체크포인트 기법과 VM 이주(migration) 기법을 이용함으로써 작업 대기 시간을 줄이는 방법을 제안한다. 이는 작업 중인 스팟 인스턴스에서 작업 실패가 발생할 경우 다른 인스턴스로 이주하여 작업을 재수행하는 기법이다. 실험 결과는 제안하는 VM 이주 기법이 작업을 수행할 수 있는 스팟 인스턴스의 가용성을 증가시킬 수 있음을 보여준다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.3B
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• pp.314-324
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• 2004

Recently, high-speed internet subscribers have grown continuously, and reached up to 10 millions. But existing network management that is responsible only for user access is confronted with many difficulties, since user access network(xDSL, Cable, B-WILL, and so on) has diversified and value added wired/wireless contents service has developed. In this paper propose the Agent based Inter Networking platform as object-oriented hierarchical system that can provide various service such as access QoS(Quality of Service), customized application service and security service according to user on demand. This system has divided into two parts(user agent and agent management system ＆ local and central management systems). Management system periodically receive status information such as bandwidth, download speed, delay, current service, and so on, and process them, then build a policy based on processed information. According to personal user profile that is generated by this policy, the customized service can be provided for users. And This system adopt the object-oriented modeling in case that system migration and integration, and implement a system that is robust and stable for security through hierarchical server system.

• Journal of the Korea Society of Computer and Information
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• v.17 no.12
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• pp.229-239
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• 2012

In 2011, more than 2000 million smartphone users are in our country. As a result, consumer demand have been developed for a variety of applications, especially in the information service-related applications that combine location-based services and augmented reality in addition to related information for the virtual reality of things are rapidly increased. This paper analysed location-based services and augmented reality technology as related research and designed and implemented the system that provides the same environment as if the user is shopping and purchasing the items in the real world and offers the information characterizing the real situation combines location-based service and augmented reality which provides with an excellent reality in the smart phone environment. The proposed system in this paper is excellent in mobility, scalability and reality as a result of analysis of functions and services compared to web-based systems and has advantages to apply for the suitable system in ubiqutous environment which can be used in anytime and anywhere.

• Journal of the Korea Society of Computer and Information
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• v.3 no.4
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• pp.19-26
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• 1998

Mobile database system address information processing based on database system in mobile computing environment. In the mobile database system, when a mobile transaction host enter a other radio coverage area called a cell while processing a transaction, it have to alter the communication network address to new database server. This is called transactional service handoff. This paper propose a transaction processing scheme for providing the proper function of this transactional service handoffs in mobile database system. This scheme apply coordinator migration mechanism which perform the transaction in new database server when posed to be the transaction service handoff. Fially, the proposed scheme will improve system performance by minimizing the tansmission of message for processing the transactions in mobile database system.