• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.233-234
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• 2009

본 논문에서는 움직임 추정을 위한 탐색 영역내의 스캔 방법을 움직임 벡터가 나올 확률에 근거하여 가변적으로 적용하여 불필요한 후보 블록을 건너뛰고 탐색 영역 안에서의 블록 정합을 PDE(partial distortion elimination) 기반으로 하여 고속 블록 매칭이 가능한 알고리즘을 제안한다. 제안한 방법은 기존의 방법보다 불필요한 계수를 효율적으로 제거하기 위하여 탐색 영역 안에서 움직임 벡터가 존재 할 확률이 가장 높은 영역은 모두 검색하고, 움직임 벡터가 존재할 확률이 낮은 영역은 가로 세로 각각 한 픽셀 건너뛰어서 블록 정합하고 만약 현재의 최소 비용보다 낮은 비용을 가지는 위치가 존재한다면 가로 세로 이웃한 4개의 화소를 추가적으로 정합하여 계산 비용을 효율적으로 감소시키면서 정확도를 높이도록 하였다. 제안한 알고리즘은 극히 낮은 화질 저하를 가지며, 기존의 전역 탐색 알고리즘에 비해 약 85% 이상의 계산 비용 감소가 있어 비디오 압축 응용 분야에 유용하게 사용될 수 있을 것이다.

• Journal of Korean Society of Transportation
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• v.23 no.7 s.85
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• pp.99-110
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• 2005

Total travel cost of route which connects origin with destination (O-D) is consist of the total sum of link travel cost and route perception cost. If the link perception cost is different according to the origin and destination, optimal route search has limitation to reflect the actual condition by route enumeration problem. The purpose of this study is to propose optimal route searching formulation and algorithm which is enable to reflect different link perception cost by each route, not only avoid the enumeration problem between origin and destination. This method defines minimum unit of route as a link and finally compares routes using link unit costs. The proposed method considers the perception travel cost at both origin and destination in optimal route searching process, while conventional models refect the perception cost only at origin. However this two-way searching algorithm is still not able to guarantee optimum solution. To overcome this problem, this study proposed an orign based optimal route searching method which was developed based on destination based optimal perception route tree. This study investigates whether proposed numerical formulas and algorithms are able to reflect route perception behavior reflected the feature of origin and destination in a real traffic network by the example research including the diversity of route information for the surrounding area and the perception cost for the road hierarchy.

• Journal of Internet Computing and Services
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• v.9 no.3
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• pp.1-8
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• 2008

With growing interest in location-based service (LBS), there is increasing necessity for nearest neighbor (NN) search through query while the user is moving. NN search in such a dynamic environment has been performed through the repeated applicaton of the NN method to the search segment, but this increases search cost because of unnecessary redundant calculation. We propose slabbed continuous nearest neighbor (Slabbed_CNN) search, which is a new method that searches CNN in the search segment while moving, Slabbed_CNN reduces calculation costs and provides faster services than existing CNN by reducing the search area and calculation cost of the existing CNN method through reducing the search segment using slabs.

• Journal of Korea Spatial Information System Society
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• v.11 no.4
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• pp.39-46
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• 2009

Generally, 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, we propose an abstract graph for path-finding with dynamic information. The abstract graph is a simple graph as real road network is abstracted. The abstract graph is created by fixed-size cells and real road network. Path-finding with the abstract graph is composed of two step searching, path-finding on the abstract graph and on the real road network. We performed path-finding algorithm with the abstract graph against A* algorithm based on fixed-size cells on road network that consists of 106,254 edges. In result of evaluation of performance, cost of exploring in path-finding with the abstract graph is about 3~30% less than A* algorithm based on fixed-size cells. Quality of path in path-finding with the abstract graph is, However, about 1.5~6.6% more than A* algorithm based on fixed-size cells because edges eliminated are not candidates for path-finding.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04a
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• pp.6-8
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• 2000

결함허용 시스템은 다양한 형태의 중복을 사용하여 신뢰도를 향상시킬 수 있는 반면, 시스템의 비용을 크게 증가시킨다. 본 논문은 만족스러운 신뢰도를 갖추면서 추가 비용을 적게 요구하는 결함허용 컴퓨터 시스템의 구조를 결정하기 위한 설계 문제를 정의하고 탐색에 기반을 둔 해결법을 제안한다. 이 때, 탐색 기법이 방문하는 탐색 공간의 크기를 줄이기 위하여 사용되는 세 가지의 유용한 사실을 설명한다. 이를 바탕으로 삼중 모듈 중복(TMR: Triple-Modular-Redundancy), 백업 예비(backup sparing), 그리고 혼합 중복(hybride redundancy) 기법과 같은 결함허용 기법들이 시스템 구조에 적용되었을 때, 탐색 공간을 줄이는 용도로 사용될 수 있는 신뢰도 제약조건을 유도해낸다.

• Journal of the Korean Society for information Management
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• v.6 no.2
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• pp.69-85
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• 1989

This study aims at reviewing the manual searching and the on-line Searching one of literature at the library or the information center, based on the comparative cost-effectiveness analysis. For this purpose, the two literature searching modes, the MEDLINE database and the corresponding Index Medicos one were used at the Medical school library of the‘s’university under same conditions of using six requests.

• Journal of the Korean Society for Library and Information Science
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• v.30 no.2
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• pp.51-86
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• 1996

The primary purpose of this study is to verify the difference of behavioural characteristics between the subject specialists and professional searchers in searching full-text databases. The major findings and conclusions from this study are summarized as follows. Analyses of Search questions(the degree of understanding with search questions, the degree of difficulty in selecting terms, and the degree of expectation of search results), search processes(the number of search terms used, the number of Boolean operators and qualifiers used, the number of documents browsed and the search time(the connecting time, time to spend per one output document, time to spend per one relevant output document) and search results(the searching efficiency(the number of relevant documents, the ,recall ratio and the precision ratio), the search cost(the total search cost. the search cost per one output document and the search cost per one relevant output document) and the degree of satisfaction with search results) are significantly different between the subject specialists and professional searchers in searching full-text databases.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.10
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• pp.1217-1224
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• 1999

이동 호스트들의 위치 정보를 관리하는 것은 이동 컴퓨터 시스템에서 중요한 문제이다. 이동 호스트가 이동할 때 위치 수정과 위치 탐색간에는 상반관계가 존재한다. 본 논문에서는 위치 서버를 이용한 간단한 quorum 기반 분산 동적 위치 관리 방법을 제안한다. 이 방법에서는 이동 호스트들의 위치 정보가 모든 위치 레지스터가 아닌 위치 레지스터들의 부분집합에서 효율적으로 관리되기 때문에 위치 수정 비용과 위치 탐색 비용이 감소된다. 그리고 위치 레지스터들의 부분집합은 동적으로 변하고, 각 위치 서버의 부하는 이동 호스트에 대한 질의율을 고려하므로 균등해진다. 제안된 알고리즘의 성능은 위치 수정비용과 위치 탐색비용의 전체비용으로 평가되었고, Prakash의 알고리즘과 비교되었다.Abstract Managing location information of mobile hosts is an important issue in mobile computing systems. There is a trade-off between location update and search, when a mobile host moves. This paper proposes a simple quorum-based distributed dynamic location management method using location registers. The cost of location updates and searches is reduced by our method because the location information of mobile hosts is managed efficiently in a subset of location registers instead of in all location registers. In our method, the subset of location registers is dynamically changed, and the load of each location register is balanced by considering query rate for mobile hosts. The performance of proposed algorithm is evaluated in terms of the total cost of a location update and a location search, and is compared with Prakash's algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.4
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• pp.365-373
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• 2019

An Image Infra-Red(IIR) seeker is widely used for precision guided munitions to provide intelligent and precise target detection in terms of high kill probability. However, there have been issues in determining the performance versus cost trade-offs due to high cost of seeker comparing to other units of the munitions. In this paper, performance/cost evaluations have been carried out to find the most cost-effective solution for developing the IIR seekers. The relationships between the critical parameters and cost are investigated to determine the optimal point which represents the low cost with high performance. It is expected that the presented approach will be able to be used for guidelines to select the appropriate IIR seeker for the given operating conditions and can be useful to estimate the cost effectiveness of the precision guided munitions at early design stage.

• 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.