• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2005년도 추계학술대회 및 정기총회
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• pp.27-37
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• 2005

The rectilinear Steiner tree problem (RSTP) is to find a minimum-length rectilinear interconnection of a set of terminals in the plane. It is well known that the solution to this problem will be the minimal spanning tree (MST) on some set Steiner points. The RSTP is known to be NP-complete. The RSTP has received a lot of attention in the literature and heuristic and optimal algorithms have been proposed, A key performance measure of the algorithm for the RSTP is the reduction rate that is achieved by the difference between the objective value of the RSTP and that of the MST without Steiner points. A hybrid evolution strategy on RSTP based upon the Prim algorithm was presented. The computational results show that the evolution strategy is better than the previously proposed other heuristic. The average reduction rate of solutions from the evolution strategy is about 11%, which is almost similar to that of optimal solutions.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2003년도 춘계공동학술대회
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• pp.1056-1064
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• 2003

The Euclidean steiner tree problem (ESTP) is to find a minimum-length euclidean interconnection of a set of points in the plane. It is well known that the solution to this problem will be the minimal spanning tree (MST) on some set steiner points, and the ESTP is NP-complete. The ESTP has received a lot of attention in the literature, and heuristic and optimal algorithms have been proposed. In real field, heuristic algorithms for ESTP are popular. A key performance measure of the algorithm for the ESTP is the reduction rate that is achieved by the difference between the objective value of the ESTP and that of the MST without steiner points. In recent survey for ESTP, the best heuristic algorithm showed around $3.14\%$ reduction in the performance measure. We present a evolution programming (EP) for ESTP based upon the Prim algorithm for the MST problem. The computational results show that the EP can generate better results than already known heuristic algorithms.

• Asian-Australasian Journal of Animal Sciences
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• 제4권1호
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• pp.21-24
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• 1991

A mixed infection of Haemophilus paragallinarum (Hpg), Mycoplasma gallisepticum (MG) and M. synoviae (Ms) was detected in layers of a poultry farm in Iwate prefecture in Japan by pathological, serological and bacteriological investigation. Hpg strains were isolated from three of five birds investigated and all strains were identified to be type C. The Hpg isolates were more susceptible in vitro to a combination of sulfamonomethoxine and ormetoprim (Ektecin) than each of sulfamethoxasol, sulfamonomethoxine, oxytetracycline, tetracycline, streptomycin, erythromycin and thianphinicol. After a total of six days' medication of 1% feed additive Ektecin, symptoms of infectious coryza of hens in the farm almost disappeared and no Hpg was detected even from birds showing nasal discharge.

• 경영과학
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• 제26권1호
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• pp.65-76
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• 2009

The undirected Steiner tree problem in graphs is known to be NP-hard. The objective of this problem is to find a shortest tree containing a subset of nodes, called terminal nodes. This paper proposes a method based on a two-step procedure to solve this problem efficiently. In the first step. graph reduction rules eliminate useless nodes and edges which do not contribute to make an optimal solution. In the second step, a max-min ant colony optimization combined with Prim's algorithm is developed to solve the reduced problem. The proposed algorithm is tested in the sets of standard test problems. The results show that the algorithm efficiently presents very correct solutions to the benchmark problems.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.197.1-197.1
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• 2003

To investigate biological active constituents from natural products, we have studied the roots of Angelica koreana Max. (Umbelliferae). Fifteen compounds were isolated from the MeOH extract by column chromatography on a silica gel. The compounds were identified as isoimperatorin, oxypeucedanin, oxypeucedanin hydrate, osthol, nodakenin, 2-hydroxy-4-methylacetophenone, cimifugin, falcarindiol, heraclenin, pabulenol, umbelliferone, demethylsuberosin, hamaudol, sec-O-glucosylhamaudol, and prim-O-glucosylcimifugin, respectivelv, by spectroscopic means. Among these, the latter eight compounds were isolated for the first time form this plant.

• 한국인터넷방송통신학회논문지
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• 제12권6호
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• pp.165-173
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• 2012

무방향성, 가중치를 가진 그래프에서 최소신장트리(Minimum Spanning Tree, MST)는 사이클이 발생하지 않으면서 모든 정점들을 간선들로 연결한 그래프로 간선들의 가중치 합이 최소가 되어야 한다. 최소신장트리(MST)를 구하는 알고리즘으로 Borůvka 알고리즘이 가장 먼저 제안되었지만 일반적으로 사용되지 않고, Prim과 Kruskal 알고리즘이 일반적으로 널리 알려져 왔다. Borůvka 알고리즘은 각 정점에서 최소 가중치를 갖는 간선(Minimum Weight Edge, MWE)을 선택하고 사이클을 제거하는 $1^{st}$ Stage와 MSF(Minimum Spanning Fores)의 MWE를 선택하는 $2^{nd}$ Stage를 수행한다. 이 과정은 시각적으로는 쉽게 MWE를 구하지만 프로그램으로 구현하는데 어려움이 있다. 본 논문은 일반화된 Borůvka 알고리즘을 제안한다. $1^{st}$ Stage에서 각 정점에서 MWE들을 모두 선택하고, Kruskal 방법을 도입하여 오름차순으로 정렬된 MWE들에 대해 사이클의 최대 가중치 간선을 제거하면서 MSF를 형성시킨다. 만약, MSF가 1개 이상 발생하면 $2^{nd}$ Stage에서 MSF 간선들을 오름차순으로 정렬시켜 MWE를 선택하였다. 제안된 알고리즘을 7개의 여러 간선들 가중치가 동일하거나 상이한 그래프에 적용하여 알고리즘 적합성을 검증하였다. 검증 결과, 일반화된 Borůvka 알고리즘은 사이클 검증에 요구되는 간선 수가 Kruskal 알고리즘보다 적어 보다 빠르게 MST를 구할 수 있었다.

• 한국수정란이식학회:학술대회논문집
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• 한국수정란이식학회 2002년도 국제심포지엄
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• pp.118-118
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• 2002

Programmed cell death (PCD) is thought as a well-controlled process by which unwanted cells are selectively eliminated. During the last decade many researches have elucidated molecules and their interactions involved in cell death by using largely in vitro induction of cell death or survival signals in a more defined manner, While these critical information and novel findings provide us with clearer understanding of mechanisms underlying cell death, it does by no means explain how PCD occurs and which cells or tissues are affected during normal embryonic development in vivo. In this study, we used zebrafish to examine whether the PCD is occurring selectively or randomly in developing embryos by whole mount in situ TUNEL analysis with specific markers for neural cells. The result revealed that the degree and distribution of TUNEL staining varied considerably throughout gastrulation stage, and there was also a number of TUNEL-negative embryos. Most of TUNEL-positive cells were scattered randomly throughout the blastoderm. During the gastrulation stage about 75 % of the embryos analyzed exhibited more than 5 TUNEL-positive cells. As the dorsal epiblast begins to thicken rather abruptly near the end of gastrulation, TUNEL-positive cells were mainly located along the dorsal side. Although there were some variations in TUNEL staining during segmentation and pharyngeal stages, TUNEL staining continued to be localized to the central nervous system, and was also detected in the sensory organs, trigeminal ganglions, and the primary sensory neurons. High levels of the cell death in developing brain between 20-somite and prim-6 stages are thought to play a role in the morphogenesis and organization of the brain. At prim-16 stage, cell death is considerably reduced in the brain region. Dying cells are mainly localized to the prospective brain region where ectodermal cells are about to initiate neurogenesis. As development progressed, high levels and more reproducible patterns of cell death were observed in the developing nervous system. Intensive TUNEL staining was restricted to the trigeminal ganglions, the primary sensory neurons, and sensory organs, such as olfactory pits and otic vesicles. Thus, PCD patterning in zebrafish embryos occurs randomly at early stages and becomes restricted to certain region of the embryos. The spatio-temporal pattern of PCD during the early embryonic development in zebrafish will provide basic information for further studies to elucidate genes involved in. regulation of PCD largely unknown in vivo during vertebrate embryogenesis.

• 정보처리학회논문지C
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• 제15C권4호
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• pp.273-280
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• 2008

무선 센서 네트워크(Wireless Sensor Network : WSN)에서 한정된 에너지를 가진 센서 노드의 동작 기간을 연장하기 위해서 LEACH와 PEGASIS, PEDAP 등의 대표적인 라우팅 방식이 제안되었다. 이들은 데이터가 완전 퓨전(perfect fusion)되는 환경에서 주기적으로 데이터를 수집하여 한 노드로 전송하는 convergecast 라우팅 방식을 사용한다. 그러나 convergecast와 에너지 분배를 동시에 다루는 과정에서 토폴로지에 관한 특성과 한계에 대한 연구는 거의 이루어지지 않았다. 이 논문은 한 번의 convergecast에 소비되는 총에너지의 관점에서 토폴로지를 다음과 같이 연구하였다. 우리는 주요 라우팅 토폴로지로 최소 스패닝 체인(Minimum Spanning Chain : MSC)과 최소 스패닝 트리(Minimum Spanning Tree : MST), PEGASIS 체인, 제안하는 LECSEN체인을 소개하거나 정의하였다. 우리는 MSC를 선형 프로그래밍(LP) 방식으로 풀었으며, MSC나 MST에 준하는 토폴로지를 만들기 위해서 LECSEN 체인을 제안하였다. Monte Carlo 방식의 시뮬레이션을 통해 토폴로지의 전체 길이와 각 링크 길이의 분포를 분석한 결과, 대부분의 WSN 환경에서 LECSEN은 MST에 필적할 만큼 에너지를 적게 소모하고, 각 센서 노드의 에너지 소비가 매우 균등하였다. 그러므로 우리는 LECSEN 체인이 WSN 라우팅에서 매우 유용하다는 사실을 확인하였다.

• Nuclear Engineering and Technology
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• 제50권3호
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• pp.356-367
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• 2018

A series of tests dedicated to station blackout (SBO) accident scenarios have been recently performed at the $Prim{\ddot{a}}rkreislauf-Versuchsanlage$ (primary coolant loop test facility; PKL) facility in the framework of the OECD/NEA PKL-3 project. These investigations address current safety issues related to beyond design basis accident transients with significant core heat up. This work presents a detailed analysis using the best estimate thermal-hydraulic code TRACE (v5.0 Patch4) of different SBO scenarios conducted at the PKL facility; failures of high- and low-pressure safety injection systems together with steam generator (SG) feedwater supply are considered, thus calling for adequate accident management actions and timely implementation of alternative emergency cooling procedures to prevent core meltdown. The presented analysis evaluates the capability of the applied TRACE model of the PKL facility to correctly capture the sequences of events in the different SBO scenarios, namely the SBO tests H2.1, H2.2 run 1 and H2.2 run 2, including symmetric or asymmetric secondary side depressurization, primary side depressurization, accumulator (ACC) injection in the cold legs and secondary side feeding with mobile pump and/or primary side emergency core coolant injection from the fuel pool cooling pump. This study is focused specifically on the prediction of the core exit temperature, which drives the execution of the most relevant accident management actions. This work presents, in particular, the key improvements made to the TRACE model that helped to improve the code predictions, including the modeling of dynamical heat losses, the nodalization of SGs' heat exchanger tubes and the ACCs. Another relevant aspect of this work is to evaluate how well the model simulations of the three different scenarios qualitatively and quantitatively capture the trends and results exhibited by the actual experiments. For instance, how the number of SGs considered for secondary side depressurization affects the heat transfer from primary side; how the discharge capacity of the pressurizer relief valve affects the dynamics of the transient; how ACC initial pressure and nitrogen release affect the grace time between ACC injection and subsequent core heat up; and how well the alternative feeding modes of the secondary and/or primary side with mobile injection pumps affect core quenching and ensure stable long-term core cooling under controlled boiling conditions.

• 한국경영과학회지
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• 제33권3호
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• pp.17-28
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• 2008

The Steiner arborescence problem is known to be NP-hard. The objective of this problem is to find a minimal Steiner tree which starts from a designated node and spans all given terminal nodes. This paper proposes a method based on a two-step procedure to solve this problem efficiently. In the first step, graph reduction rules eliminate useless nodes and arcs which do not contribute to make an optimal solution. In the second step. ant colony algorithm with use of Prim's algorithm is used to solve the Steiner arborescence problem in the reduced graph. The proposed method based on a two-step procedure is tested in the five test problems. The results show that this method finds the optimal solutions to the tested problems within 50 seconds. The algorithm can be applied to undirected Steiner tree problems with minor changes. 18 problems taken from Beasley are used to compare the performances of the proposed algorithm and Singh et al.'s algorithm. The results show that the proposed algorithm generates better solutions than the algorithm compared.