• Proceedings of the Korea Information Processing Society Conference
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• 2001.04b
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• pp.809-812
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• 2001

본 연구에서는 웹과 분산된 환경에서 신뢰할 수 있고 확장성 있는 워크플로우 관리 시스템의 구조와 워크플로우 관리 시스템의 핵심인 워크플로우 엔진의 구조를 설계하고 제안한 구조에 맞는 프로토타입 엔진을 구현하였다. 구현된 엔진은 다양한 Transition 타입을 지원하므로 실제 B2B환경에서 발생하는 다양한 형태의 비즈니스 타입을 지원한다. 또한 엔진 내의 인스턴트를 관리하는 인스턴트 관리자에 인스턴트들 사이의 처리 순서를 결정하는 인스턴트 스케줄링 기능이 들어있다. 이 인스턴트 스케줄링 기능은 인스턴트들을 사이에 우선순위를 부여한다든지 인스턴트의 실시간 보장을 위한 여러 관련 처리가 가능케 하여준다. 이외에 Invoked Application으로 웹 애플리케이션을 사용할 경우 Relevant Data를 어떻게 전달할 것인지, Notification 서비스, Monitoring 서비스 기능들을 고려하여 설계 및 구현하였다.

• Journal of KIISE:Databases
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• v.33 no.5
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• pp.495-512
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• 2006

Recently, researches on a future position prediction of moving objects have been progressed as the importance of the future position retrieval increases. New index structures are required to efficiently retrieve the consecutive positions of moving objects. Existing index structures significantly degrade the search performance of the moving objects because the search operation makes the unnecessary extension of the node in the index structure. To solve this problem, we propose a space partition based index structure considering the mobility of moving objects. To deal with the overflow of a node, our index structure first merges it and the sibling node. If it is impossible to merge them, our method splits the overflow node in which moving properties of objects are considered. Our index structure is always partitioned into overlap free subregions when a node is split. Our split strategy chooses the split position by considering the parameters such as velocities, the escape time of the objects, and the update time of a node. In the internal node, the split position Is determined from preventing the cascading split of the child node. We perform various experiments to show that our index structure outperforms the existing index structures in terms of retrieval performance. Our experimental results show that our proposed index structure achieves about $17%{\sim}264%$ performance gains on current position retrieval and about $107%{\sim}19l%$ on future position retrieval over the existing methods.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.393-393
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• 2004

• Proceedings of the Korea Information Processing Society Conference
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• 2001.04a
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• pp.487-490
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• 2001

Mobile IP는 HA(Home Agent)와 FA(Foreign Agent)간의 터널링을 이용하여 IP망에서 단말기의 이동성을 지원하는 표준 프로토콜이다. 하지만 이러한 터널링 방법은 현재 제안되고 있는 인터넷 서비스 연구 즉 통합 서비스(Integrated Service) 및 차별화 서비스(Differentiated Service) 등을 적용하기 위해서는 많은 문제점을 가진다. 대표적인 문제점은 통신망에서는 전송되는 IP 패킷의 헤더에 의해서 세션을 구별하게 되는데 터널링 패킷의 경우 실제 세션과 다른 헤더를 사용하므로 망에서 세션에 대한 처리를 하기 위해서는 내재된 패킷의 정보가 터널링 패킷의 헤더에 반영되어야 한다. 본 논문은 이러한 문제점을 도메인 게이트웨이 라우터에 HA/FA 기능을 추가하는 동시에 RSVP(Resource Reservation Protocol) 플로우를 군집하는 도메인 레벨 QoS(Quality of Service)와 이동성 지원 프로토콜에 QoS를 의존하는 마이크로 레벨 QoS를 분리하는 이단계 구조를 통해 단-대-단 QoS를 보장할 수 있는 방안을 제안한다.

• Journal of Digital Convergence
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• v.18 no.2
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• pp.385-393
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• 2020

Focusing on the Chinese market of MSNG (Mobile Social Network Game), perceived flow and satisfaction were designed as parameters, purchasing intention was set up as dependent variables, the purpose of present research is to analyze the factors influencing purchase intention of the paid items in mobile social games by studying the game and personal characteristics in terms of interoperability, accessibility, interesting, operability, innovativeness and challenge. Data was collected by questionnaires, Amos was employed to analyze the relationship between purchase intention and target influencing factors. Results showed that characteristics of game and consumers of MSNG have positive effects on the flow and satisfaction of paid items. Moreover, the flow of paid items in MSNG has a positive effect on satisfaction; the flow and satisfaction of paid items in MSNG have a positive effect on purchase intention. more samples and references should be involved in the further study in order to acheive an comprehensive result on comparative study of the social and cultural characteristics between Chinese MSNG and Korean counterpart.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.1
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• pp.7-14
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• 2014

The rapid increase of mobile devices such as smart phone and smart pad have raised the needs for seamless multimedia services during moving at anytime and anywhere. Current 4G mobile devices are equipped with both 4G (LTE) and WLAN (WiFi) interfaces, and mobile services operators provide wireless Internet services using 4G network with a wider coverage and WiFi zone. Generally users prefer to use the Internet services through WLAN rather than LTE in the coverage of WLAN. However, since WLAN has a long L2 handover latency, it is difficult to support seamless services during a handover. In this paper, we proposed an efficient handover scheme based on flow mobility for WLANs to support a seamless service during handovers by using the overlaid 4G network with a wider coverage. Also, we showed the outperformance of the proposed scheme on a testbed.

• Journal of the Korea Society of Computer and Information
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• v.19 no.12
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• pp.71-80
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• 2014

Recently, most mobile nodes, such as smartphones, will have multiple wireless radio interfaces. This feature allows a mobile node to access a multi-network through multiple wireless radio interfaces simultaneously. Accordingly, various networking technology has been studied to use wireless multi-interface more efficiently. In this paper, MPTCP based handover scheme is proposed to reduce data loss and end-to-end latency during the handover in PMIPv6 domain. The proposed scheme performs 2-step flow mobility on the multi-path established through the multi-interface of mobile node in the handover procedure and uses MPTCP subflow function to overcome end-to-end disconnection during the handover. Therefore, the proposed scheme takes the advantage of being able to minimize data loss and a latency generated during performing the handover of mobile node.

• Journal of Internet Computing and Services
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• v.10 no.2
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• pp.65-73
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• 2009

IEEE802.11 Wireless LAN(WLAN) is being widely used in public space such as airport, and increases the networking boundary in campus and enterprise, and it has lastly attracted considerable attention for mesh network and converged network with other 3G mobile communication networks. In WLAN, load balancing among Access Points(AP) is an important issue for efficient resource management or supporting the Quality of Service(QoS) of traffic, but most researches focused on the AP selection in network entry or roaming of Stations(STA). In this paper, we propose an AP-Initiated Flow Redirection(FR) for AP load balancing by monitoring AP's availability in the true sense. When the AP's resource becomes almost saturated, that is used more than a specific threshold, the AP queries the roaming possible neighbor APs about their availability and calculates the distribution of traffic load with statistical methods such as entropy or chi-square. Finally, the AP decides flows and new APs for redirection and performs it. Our simulation results show that our FR mechanism increases the performance in the various views.

• Journal of Digital Convergence
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• v.9 no.6
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• pp.217-229
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• 2011

Conventional IT device has been evolving into smart device based on more powerful computing, the adoption of platforms, and next generation networking. There are not many empirical studies with regard to the early adoption stage of smart IT technology devices. This paper aims to investigate intention to use smart device based an extended technology acceptance model (TAM) with flow empirically. We get the results that there are positive influences among multidimensional user characteristics and flow, perceived usefulness and the intention to use. According to this results, companies which want to dominate the market in advance should understand the characteristics of potential consumers in developing marketing strategies and contents.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4B
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• pp.281-290
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• 2002

In this paper, we propose an efficient packet forwarding method for an IP-based wireless Internet access network. Packets are forwarded along with a flow, that is a kind of connection-oriented connection and established before delivering packets. For this purpose, we also propose a flow resolution method and a modified IPv6 header for delivering packet in the wireless Internet access network. In addition, the method to support the mobility of mobile stations is explained, and the implementation issues are discussed. In order to estimate the performance of the proposed method, we analyzed the delay time to deliver packets in the wireless Internet access network. The numerical results show that the proposed method is very efficient, in the view point of delay.