• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.245-248
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• 2009

Recently, Many studies have been progressing to path-finding with dynamic information on the Terminal Based Navigation System(TBNS). However, the most of existing algorithms are based on $A{\ast}$ algorithm. Path-finding algorithms which use heuristic function may occur a problem of the increase of exploring cost in case of that there is no way determined by heuristic function or there are 2 way more which have almost same cost. In this paper, two abstract graph(AG) that are different method of construction, Homogeneous Node merging($AG^H$) and Connected Node Merging($AG^C$), are implemented. The abstract graph is a simple graph of real road network. The method of using the abstract graph is proposed for reducing dependency of heuristic and exploring cost. In result of evaluation of performance, $AG^C$ has better performance than $AG^H$ at construction cost but $AG^C$ has worse performance than $AG^H$ exploring cost.

• Journal of The Korean Association of Information Education
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• v.2 no.2
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• pp.252-259
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• 1998

Vehicle navigation systems employ a certain route planning algorithm that provides the shortest path between the starting point and the destination point. The performance of a given route planning algorithm is measured through the degree of optimal route selection and the time cost to complete searching an optimal path. In this paper, various route planning algorithms are evaluated through computer simulation based on a real digital map database. Among those algorithms evaluated in this paper, the Modified Bi-directional A${\ast}$ algorithm is found to be the best algorithm for use in vehicle navigation systems.

• The Transactions of the Korea Information Processing Society
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• v.4 no.10
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• pp.2477-2484
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• 1997

Best-first heuristic search algorithm, such as $A^{\ast}$ algorithm, are one of the most important techniques used to solve many problems in artificial intelligence. A common feature of heuristic search is its high computational complexity, which prevents the search from being applied to problems is practical domains such as route-finding in road map with significantly many nodes. In this paper, several heuristic search algorithms are concerned. A new dynamic weighting heuristic method called the pat-sensitive heuristic is proposed. It is based on a dynamic weighting heuristic, which is used to improve search effort in practical domain such as admissible heuristic is not available or heuristic accuracy is poor. It's distinctive feature compared with other dynamic weighting heuristic algorithms is path-sensitive, which means that ${\omega}$(weight) is adjusted dynamically during search process in state-space search domain. For finding an optimal path, randomly scattered road-map is used as an application area.

• The Transactions of the Korea Information Processing Society
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• v.4 no.10
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• pp.2470-2476
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• 1997

We propose a new real-time search algorithm and provide experimental evaluation and comparison of the new algorithm with mini-min lookahead algorithm. Many other real-time heuristic-search approached often divide the problem space to several sub-problems. In this paper, the proposed algorithm guarantees not only the sub-problem deadline but also total deadline. Several heuristic real-time search algorithms such as $RTA^{\ast}$, SARTS and DYNORA have been proposed. The performance of such algorithms depend on the quality of their heuristic functions, because such algorithms estimate the search time based on the heuristic function. In real-world problem, however, we often fail to get an effective heuristic function beforehand. Therefore, we propose a new real-time algorithm that determines the sub-problem deadline based on the status of search space during sub-problem search process. That uses the cut-off method that is a dynamic stopping-criterion-strategy to search the sub-problem.

• The Journal of the Korea Contents Association
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• v.20 no.3
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• pp.18-30
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• 2020

Recently, as graph-structured data is widely used in various fields such as social networks and semantic Webs, needs for an effective and efficient search on a large amount of graph data have been increasing. Previous keyword-based search methods often find results by considering only the relevance to a given query. However, they are likely to produce semantically similar results by selecting answers which have high query relevance but share the same content nodes. To improve the diversity of search results, we propose a top-k search method that finds a set of subtrees which are not only relevant but also diverse in terms of the content nodes by controlling their similarity. We define a criterion for a set of diverse answer trees and design two kinds of diversified top-k search algorithms which are based on incremental enumeration and A^⁎ heuristic search, respectively. We also suggest an improvement on the A^⁎ search algorithm to enhance its performance. We show by experiments using real data sets that the proposed heuristic search method can find relevant answers with diverse content nodes efficiently.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.448-449
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• 2016

Enlargement and complexification of current structures increase the expected casualty in case of accident in those e.g., fire. In that case, there only have been basic instructions such as announcement of that situation, alarm bell, exit signs, etc. but any guidance to lead to proper escape route was not been provided so far. To tackle the problem, several schemes have been proposed. However, various risk factors were not considered and route discovery performance must be improved to be applied to structures. Therefore, this paper proposes an optimal route discovery system for emergency escape from disaster situations which takes into account various possible risk factors and enhances the searching efficiency by using the $A^{\ast}$ algorithm. Performance evaluation by computer simulation shows that the proposed scheme effectively leads to safe escape route.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.449-452
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• 2005

그레이팅(grating) 생산 공정에서 절단공정은 패널(panel)을 원하는 형태의 그레이팅으로 절단하여 제품을 생산한다. 실제 절단이 이루어지기 전에 절단 계획을 생성하는데, 이것은 절단 대상이 되는 그레이팅들의 배치 방법을 결정한다. 이 계획은 제품의 생산비용의 증감에 중요한 역할을 한다. 절단 계획의 생성은 2차원 절단 문제와 유사하다. 본 논문에서는 금속 그레이팅 생산 공정의 절단 계획에 대하여 연구하고 인공지능 탐색 방법 중 하나인 $A{\ast}$ 알고리즘을 계획 생성에 적용한다. 또한 시뮬레이션을 통하여 자재의 손실을 기준으로 제안된 방법과 기존의 방법을 비교 평가 하겠다.

• Food Industry And Nutrition
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• v.10 no.2
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• pp.26-31
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• 2005

천연물 유래 기능성 물질 탐색의 일환으로 녹차 추출물의 산업적 적용을 용이하게 하기 위하여 감마선 조사를 병용하여 추출물의 색도 및 라디칼 소거능을 확인하고, 이 추출 파우더를 돈육 패티에 적용하여 항산화, 색도 및 관능검사를 통해 기호도를 조사하였다. 생리활성을 가지는 녹차 잎 추출물의 라디칼 소거능은 $68.2\%$를 나타냈으며, 20 kGy로 조사했을 경우 비조사구와 큰 차이를 나타내지 않았다. 또한, 감마선조사에 의한 색도의 변화는 감마선 조사 후 $L^{\ast}-value$는 증가했고, $a^{\ast}$- 및 $b^{\ast}-value$는 감소하는 것으로 확인되었다. 또한, 녹차 잎 추출 파우더를 돈육 패티에 적용해본 결과 비첨가구에 비해 라디칼 소거능 및 지질 산화를 지연시키며, 조사된 녹차 잎 추출 파우더를 첨가한 돈육패티가 비첨가구 혹은 비조사된 녹차 잎 첨가구에 비해 저장 기간에 따라$L^{\ast}-value$가 높게 나타났다. 또한, 모든 처리구에서 관능적으로도 큰 차이를 보이지 않았다 그러므로 천연물 유래 녹차 추출물 파우더는 돈육 패티의 기능성 첨가제로서 우수하며, 감마선 조사는 녹차 잎 추출 파우더의 산업적 적용을 용이하게 하는 방법 중의 하나라고 사료된다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.1
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• pp.181-190
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• 2007

This paper presents a collision avoidance system for intelligent ship. Unlike collision avoidance system of other unmanned vehicles, the collision avoidance system for intelligent ship aims at not only deriving a reasonable and safe path to the goal but also keeping COLRECs(International Regulations for Preventing Collisions at Sea). The heuristic search based on the BK-products is adopted to achieve the general purpose of collision avoidance system; deriving a reasonable and safe path. The rule of action to avoid collision is adopted for the other necessary and sufficient condition; keeping the COLREGs. The verification of proposed collision avoidance system is performed with scenarios that represent encounter situations classified in the COLREGs, then it is compared with $A^{\ast}$ search method in view of optimality and safety. The analysis of simulation result revels that the proposed collision avoidance system is practical and effective candidate for real-time collision avoidance system of intelligent ship.

• Korean Journal of Plant Resources
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• v.17 no.3
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• pp.283-288
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• 2004

Effect of Siho (Bupleurum falcatum L.) extracts on liver function were investigated in CCl4 intoxicated rats. Plasma $\alpha$-fetoprotein and total protein concentration showed a tendency to decrease in Siho extracts groups. However plasma albumin concentration showed no significantly different in all treatment groups. Activities of plasma asparate aminotransferase and alanine aminotransferase in Siho extracts groups showed a lower values than control group. Alkan phosphatase and lactate dehydrogenase activities showed a tendency to decrease in Siho extracts groups. However ${\gamma}$-glutamyl transferase activity showed no significantly different in all treatment groups. Concentration of plasma triglyceride and total cholesterol showed no significantly different in all treatment groups.