• The Journal of the Korea Contents Association
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• v.5 no.4
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• pp.36-44
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• 2005

Recommender services are being used by an ever-increasing number of mobile commerce applications to help consumers find items to purchase with the use of the situated contexts. In this paper, we propose a new leveled recommendation for context-aware mobile commerce. This enables a consumer to obtain relevant information efficiently by using leveled recommendation, patterns and prefetching. This paper describes the method and application scenarios. Several experiments are performed and the results verify that the proposed method's recommendation performance is better than other existing methods.

• Journal of the Korean Data and Information Science Society
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• v.17 no.4
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• pp.1261-1270
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• 2006

This paper proposes a mobile computing prefetching method providing the effective information about location change of mobile user or mobile computing in mobile information services. For mobile computing environments, there exist restrictions as like low bandwidth, latency and traffic. To solve those problems, a variety of techniques have been developed including caching and prefetching. In this paper we present a Statistical Poisson Prefetching Scheme using the reference count to provide a mobile user information that will be likely referenced in the near future. Comparing to existing methods in numerical results, the proposed method improves the prefetching performance to give the maximum effectiveness and reduces the failure rate of information searching.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.1359-1363
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• 2007

인터넷 상에서 VoD 서비스를 제공하기 위해서는 시스템 자원과 네트워크 대역폭을 효율적으로 사용 해야 한다. 이러한 효율성을 높이기 위해서 오버레이 멀티캐스트를 생각 할 수 있지만 실제로 On-Demand 서비스에 적용하기 위해서는 많은 결점의 보완이 필요하다. 본 논문에서는 이러한 결점을 보완하고 기존 시스템의 간단한 확장으로 VoD 서버의 자원과 대역폭을 효율적으로 사용할 수 있는 오버레이 멀티캐스트 모델을 제안 한다. 제안된 모델은 호스트의 공유 버퍼와 패칭 채널 그리고 트리구성 알고리즘을 이용하여 사용자 데이터의 요구시점은 물론 다양한 재생율 지원 등 제한이 없는 On-Demand 서비스 수행이 가능하다.

• Journal of Industrial Technology
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• v.24 no.B
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• pp.177-186
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• 2004

The main bottleneck for a VOD system is bandwidth of storage or network I/O due to the high bandwidth requirements and long-lived nature of digital video. Patching is one of the most efficient techniques to overcome the bottleneck of the VOD system through the use of multicast scheme. In this paper, we propose a new patching scheme, P2P proxy patching, for improving the typical patching technique by jointly using the proxy prefix caching scheme and the P2P proxy. In our proposed scheme, each client play a role in a proxy for multicasting a regular stream to other clients that request the same stream. Due the use of the P2P proxy and the prefix caching, the server bandwidth is required significantly less than that of the typical patching technique. In the performance study, we show that our patching scheme can reduce the server bandwidth requirements compared with the existing patching techniques.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06d
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• pp.122-125
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• 2011

버퍼 오버플로우(buffer overflow) 취약점은 1988년 모리스 웜(Morris worm)을 통하여 널리 알려진 이후 이를 해결하기 위한 많은 연구들이 진행되었으며, 동시에 이를 이용한 공격 역시 끊임없이 이루어지고 있다. 기존의 버퍼 오버플로우 취약점에 대한 연구는 크게 컴파일러 및 라이브러리, 커널, 하드웨어 단계로 나눌 수 있다. 하지만 이러한 방법들은 다양한 한계를 가진다. 본 논문은 이러한 문제들을 해결하기 위하여 버퍼 오버플로우 취약점을 발생시키는 코드를 바이너리에서 직접 검색하고, 이를 패치하여 버퍼 오버플로우 취약점을 제거하는 BinaryReviser를 구현하였다.

• Journal of Ocean Engineering and Technology
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• v.22 no.3
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• pp.89-95
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• 2008

Fatigue cracked components often needs to be repaired during service. Standard repair schemes involve strengthening the component by connecting reinforcing members by means of rivets or welding by reducing the crack-tip stress intensity factors. Recent technological advances in fiber reinforced composite materials and adhesive bonding have led to the development of efficient repair schemes. In this study, the influence of various shape parameters on fatigue crack growth in the CCT type uniform thickness plates and the thin-ta-thick type stiffened panels repaired with woven fabric type Kevlar-Epoxy composite patch are studied experimentally.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11c
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• pp.1547-1550
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• 2003

네트워크의 발달과 다양한 서비스의 요구에 따라 새로운 소프트웨어의 패러다임에 대한 요구와 함께 이동 에이전트에 대한 많은 연구가 진행 중이다. 이동 에이전트의 수행에 있어 이주비용은 이동 에이전트의 성능에 많은 영향을 미친다. 본 논문에서 이동에이전트의 이주비용을 최적화하기 위한 기법을 제안한다. 제안하는 이주기법의 특징은 다음과 같다. 첫째, 네트워크 상태 및 플랫폼 상태변화에 적절하게 대응할 수 있는 동적 경로를 생성하여 에이전트 수행 효율을 높인다. 둘째, 수행할 코드를 프리패칭하여 이동 데이터량을 줄이고, 필요한 에이전트를 미리 인스턴스시켜 수행 시간을 단축한다. 셋째, 체크포인트기법을 사용하여 에이전트 수행 중에 에러가 발생할지라도 에이전트는 재 수행을 하지 않고 에러 이전의 상태로 복구하는 방법을 사용하여 수행 효율을 높인다.

• 전자공학회논문지 IE
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• v.43 no.1
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• pp.67-72
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• 2006

According to the growth of wireless networks, and the spread of mobile devices, the provision of recommender services to help consumers find items to purchase with the use of the suited contexts is an important issue in mobile commerce. In this paper, we propose a proactive mobile commerce service that enables a consumer to obtain relevant information efficiently by using differentiated recommendation in context-aware environment. This paper describes the recommendation method and presents grocery shopping application prototype that implement the method. Several experiments are performed and the results verify that the proposed method's recommendation performance is better than other existing methods.

• International Journal of Highway Engineering
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• v.2 no.3
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• pp.145-153
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• 2000

Pavement evaluation is a fundamental component for rational pavement management. Optimal rehabilitation method and the priority of rehabilitation should be based on the evaluation data. Some types of pavement condition index are needed for objective evaluation of Pavement condition and management of road network. In this study a expressway concrete pavement condition index model is developed through regression analysis that correlates panel rating with distress measurement from the test sections. The derived condition index can be used for network level PMS for the expressway concrete pavement. Correlation coefficient of the model was 0.68. The selected independent variables were International Roughness Index, crack and area of patching.

• The Journal of Society for e-Business Studies
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• v.13 no.4
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• pp.161-171
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• 2008

The most important reason for increasing web traffic and overloaded web servers is a dramatic growth of web users which leads to a great dissatisfaction of each individual user. For overcoming this situation, studies for an acceleration of web content have been conducted actively. We use web caching technology for reducing the load of the web system and traffic in the network. In this paper, we proposed a new web caching technology with the related web object which based on the unit of web processing and characteristics of the web object. Also we verified the availability of the proposed system with comparison and experiments.,