• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.11
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• pp.911-923
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• 2013

Multipath routing is one of challenging issues for improving the reliability of end-to-end data delivery in wireless sensor networks. Recently, a disjointedness and management of path have been studying to enhance the robustness and efficiency of the multipath routing. However, previous multipath routing protocols exploit the disjointed multipath construction method that is not to consider the wireless communication environment. In addition, if a path failures is occurred due to the node or link failures in the irregular network environment, they maintain the multipath through the simple method that to construct a new extra path. Even some of them have no a method. In order to cope with the insufficiency of path management, a hole detouring scheme, to bypass the failures area and construct the new paths, was proposed. However, it also has the problem that requires a heavy cost and a delivery suspension to the some or all paths in the hole detouring process due to the centralized and inflexible path management. Due to these limitations and problems, the previous protocols may lead to the degradation of data delivery reliability and the long delay of emergency data delivery. Thus, we propose a flexible disjoint multipath routing protocol which constructs the radio disjoint multipath by considering irregular and constrained wireless sensor networks. It also exploits a localized management based on the path priority in order to efficiently maintain the flexible disjoint multipath. We perform the simulation to evaluate the performance of the proposed method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.1
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• pp.97-105
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• 2015

Recently, due to an explosive growth of the internet traffic, the limitations of a current framework for a mobility management have been focused. The current centralized mobility management is prone to several problems and limitations: suboptimal routing, low scalability, signaling overhead, and a single point of failure. To overcome these problems and limitations, IETF is working about the distributed mobility management scheme that the centralized mobility functions of HA(Home Agents) are distributed to networks edges such as access routers. These distributions of mobility functions overcome the limitations of the centralized mobility managements and go with the trend of flat networks e.g. more simple network architecture. This paper analyzes the distributed mobility management based on Proxy Mobile IPv6 and demonstrates the performance superiority.

• Journal of the Korea Society of Computer and Information
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• v.20 no.4
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• pp.25-32
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• 2015

The Genetic algorithm is a search algorithm using evaluation, genetic operator, natural selection to populational solution iteratively. The convergence and divergence characteristic of genetic algorithm are affected by selection strategy, generation replacement method, genetic operator when genetic algorithm is designed. This paper proposes fast convergence genetic algorithm for time-limited robot path planning. In urgent situation, genetic algorithm for robot path planning does not have enough time for computation, resulting in quality degradation of found path. Proposed genetic algorithm uses fast converging selection strategy and generation replacement method. Proposed genetic algorithm also uses not only traditional crossover and mutation operator but additional genetic operator for shortening the distance of found path. In this way, proposed genetic algorithm find reasonable path in time-limited situation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.463-466
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• 2009

MANET(Mobile Ad-Hoc Network) mean network that configured to mobile device without the help of Fixed infra. Node in MANET constraints have such as liquidity and battery. Node concentrated areas or the size of the network becomes large that causes some issues. It's the problem of routing overhead when path set, path navigation and reset path. In this paper ZRP(Zone Routing Protocol) and ZHLS(Zone-Based Hierarchical Link State) are analyzed. As a result, offers the Fixed ZRP.

• Journal of the Korea Society of Computer and Information
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• v.10 no.1 s.33
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• pp.201-208
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• 2005

Recently, the container terminal requires the study of method to increase efficiency through change of its operation method. Loading plan is a very important part to increase the efficiency of container terminal. Loading Plan is largely divided into two cases, deciding loading location and loading scheduling and this Paper proposes a more efficient method of container loading scheduling. Container loading scheduling is a problem of combination optimization to consider several items of loading location and operation equipments. etc. An existing method of cluster composition that decides the order of container loading scheduling has a restriction to increase the efficiency of work owing to rehandling problem. Therefore, we Propose a more efficient method of container loading scheduling which composes containers with identical attribution, based on ship loading list and yard map, into stack units of cluster, applying to hierarchical clustering method, and defines the restriction of working order. In this process, we can see a possible working path among clusters by defining the restriction of working order and search efficiency will be increased because of restricted search for working path.

• Journal of KIISE:Databases
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• v.27 no.2
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• pp.216-226
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• 2000

This paper suggests a new access path, hashed B-tree which is an efficient access method for integrity checking. Hashed B-tree is based on the observation that most query patterns in enforcing integrity constraints are point queries. Hashed B-tree compresses the key by hashing procedure, which reduces the height of tree and results in fast node search. This method has the advantages such as it can be implemented easily and use the B-tree concurrency control and recovery algorithm with minor modifications.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.364-366
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• 2001

현재 제안되고 있는 멀티캐스트 메커니즘은 각 라우터에서 멀티캐스트 라우팅을 위만 상태 정의를 바탕으로 데이터를 전송하게 된다. 따라서, 각 라우터는 상태정보를 유지해야 하므로 확장성 문제가 발생하게 된다. 이 문제의 해결을 위하여 제안된 메커니즘으로 Explicit Multicast (Xcast)[1]가 있다. 하지만 Xcast의 경우 각 경로상의 라우터는 반드시 Xcast를 탑재해야 하는 제약을 가지고 있다. 이러만 제약은 현재의 망에 구현 관점에서는 큰 문제가 된다. 따라서 본 논문은 상태 정보가 없이 멀티캐스트를 점진적으로 적응할 수 있는 Multicast based on Virtual Topology (MVT)즉 제안한다. MVT는 멀티캐스트 데이터가 분기되는 라우터를 분기라우터로 지정하고 분기라우터간의 가상 토폴로지 정보를 헤더에 삽입함으로써 멀티캐스트 서비스를 제공하는 메커니즘이다.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06b
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• pp.150-152
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• 2012

일반적으로 테스트 데이터 자동 생성을 지원하기 위해 심볼릭 실행기나 제약 해결기와 같은 도구를 요구한다. 그러나 이와 같은 도구들을 개발하는 것은 상당한 노력이 요구되는 것도 사실이다. 이 논문에서는 이러한 도구들의 지원 없이 분기 커버리지를 효과적으로 달성할 수 있는 테스트 데이터 생성 방법을 제안한다. 이를 위해 경로 지향 테스트 데이터 생성을 위해 개발된 Korel의 방법을 확장하여 프로그램의 분기들을 가능한 많이 실행할 수 있는 테스트 데이터를 효과적으로 생성하는 방법을 제안한다.

• Korean Journal of Food Science and Technology
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• v.51 no.2
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• pp.141-146
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• 2019

Sparassis crispa is an edible mushroom that is distributed in Korea, Japan, Europe, and North America. It exerts various biological activities such as immunopotentiation, anti-diabetic, anti-cancer, and anti-inflammatory effects. Recently, we separated the health functional non-aqueous fraction from the chloroform extract of S. crispa (SCF4). In this study, we evaluated the antiangiogenic activity of SCF4 in human umbilical vein endothelial cells (HUVECs). SCF4 effectively inhibited vascular endothelial growth factor (VEGF)-induced cell growth at concentrations ($5-25{\mu}g/mL$) showing no cytotoxic effects. SCF4 inhibited VEGF-induced invasiveness and tube formation ability, which are in vitro angiogenic features of HUVECs, in a dose-dependent manner. In addition, SCF4 markedly suppressed in vivo angiogenesis of chorioallantoic membrane from growing chick embryos without cytotoxicity. Furthermore, SCF4 downregulated the phosphorylation of VEGFR2, AKT, and ERK1/2, which are major angiogenic signal mediators. These results suggest that SCF4 inhibited angiogenesis by suppressing the VEGFR2 signaling pathways without cytotoxicity.

• Korea Trade Review
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• v.42 no.3
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• pp.49-74
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• 2017

Drawing on the organizational learning theory, we argue that international patenting allows firms to assess the potential value of their innovation in host countries and find out latent local competitors. The information obtained from international patenting enables firms to make refined innovations that facilitate export performance. However, structural inertia and old knowledge can impede learning from international patenting. Thus, we expect larger firms and older firms to display greater reluctance to use the knowledge obtained from international patenting. Our empirical analysis of Korean pharmaceutical companies from 1998 to 2010 shows that international patent application increases export intensity but firm size and age weaken the positive effect of international patenting on export performance.