• 한국정보처리학회논문지
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• 제6권4호
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• pp.1129-1135
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• 1999

DTW 알고리즘을 이용한 고립단어 인식은 화자종속이라는 상황에 있어서는 좋은 인식 율을 제공하여 준다. 그러나 DTW 알고리즘은 검색해야 할 단어가 많을 경우 검색시간이 상대적으로 높아지게 되므로 현실적으로 적용하기가 힘들다. 웹에서의 교육용 학습 지와 같이 상황 의존적 단답형 질의 응답을 요구하는 시스템의 경우에 있어서는 주어진 질문에 대한 응답이 비교적 제한되어 있어 검색대상을 줄일 수 있다. 본 논문에서는 이와 같은 상황에서 사용할 수 있는 저가형 음성 인식기를 DTW로 구현하였다. DTW의 단점을 보완하기 위해 검색할 대상을 상황에 따라 줄이는 방법을 이용하였다. 질문에 따라 관심대상을 선정하여 이들만을 검색대상으로 삼았다. 실제적인 구현을 통하여 검색대상을 줄인 결과 높은 인식 율을 얻을 수 있었고, 그룹을 설정한 만큼의 빠른 검색시간을 얻을 수 있었다.

• 한국음향학회지
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• 제21권3호
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• pp.304-309
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• 2002

LSP (Line Spectrum Pairs) 파라미터는 음성코덱 (codec)이나 인식기에서 음성신호를 분석하여 전송형이나 저장형 파라미터로 변환되어, 주로 저전송률 음성부호화기에 사용된다. 그러나 LPC (Linear Predictive Coding) 계수를 LSP로 변환하는 방법이 복잡하여 계산시간이 많이 소요된다는 단점이 있다. 기존의 LSP변환 방법 중 음성 부호화기에서 주로 사용하는 실근 (real root)방법은 근을 구하기 위해 주파수 영역을 순차적으로 검색하기 때문에 계산시간이 많이 소요되는 단점을 갖는다. 본 논문에서 기존의 실근 방법과 비교 평가한 알고리즘은 첫 번째 검색 대역에 멜 스케일 (met scale)을 사용하였고, 두 번째는 LSP 파라미터의 분포 특성을 조사하여 이를 토대로 검색구간의 순서와 검색간격을 달리 하였다. 실험결과, 기존의 실근 방식에 비하여 두 가지 방식 모두가 변환시간의 47% 이상이 감소되는데 반하여 동일한 근을 찾음을 알 수가 있었다.

• 한국정보통신학회논문지
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• 제13권7호
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• pp.1422-1428
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• 2009

독립형 무선 인지 시스템은 보통 채널에 대한 면허를 가지는 기사용자가 사용하지 않는 빈 채널을 사용하는 2차 사용자로서 동작한다. 기존연구에서는 이와 같은 2차 사용자가 가용한 채널을 찾을 때, 순차 혹은 무작위로 채널을 선택하여 기사용자의 사용 유무를 확인하였다. 하지만 이러한 방법은 무선 채널의 특성에 맞지 않다. 그러므로 본 논문에서는 이전에 채널을 기사용자가 사용한 경우를 고려하여 가중치 값을 결정하고, 각 채널별 상태 값 중에서 작은 순서대로 채널을 선택함으로써 빈 채널을 찾는데 소요되는 시간을 줄이는 방법을 제안하고, 2차 사용자의 평균 채널 찾기 시간과 평균 전송 횟수의 관점에서 순차적, 무작위적 방법과 그 성능을 비교 분석 한다.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1994년도 제11회 음성통신 및 신호처리 워크샵 논문집 (SCAS 11권 1호)
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• pp.188-194
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• 1994

Code excited linear prediction speech coders exhibit good performance at data rates as low as 4800bps. But the major drawback to CELP type coders is their large computational requirements. Therefore, in this paper a comparative performance study of three pitch searching algorithms for the CELP vocoder was conducted. For each of the algorithms, a standard pitch searching algorithm was used by the full pitch searching algorithm that was implimented in the QCELP vocoder. The algorithms used in this study is to reduce the pitch searching time 1) using the skip table, 2) using the symmetrical property of the autocorrelation , and 3) using the preprocessing autocorrelation, 4) using the positive autocorrelation, 5) using the preliminary pitch. Performance scores are presented for each of the five pitch searching algorithms based on computation speed and on pitch prediction error.

• 대한인간공학회지
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• 제11권1호
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• pp.21-29
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• 1992

A study on analyze the effect of positive and negative contrast for user performance on the VDT tasks);text typing, text deiting, and searching task) has been performed. The performances were measured in terms of the completion time and the number of errors. The results of each VDT task are followings. In the text typing task and the searching task, the performances measured by the number of errors were better at the condition of negative contrast than at that of positive contrast. In the text deiting task, the performance showed a reverse tendency.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.759-762
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• 2005

Recently, Intelligent Transportation System(ITS) has been applied to satisfy increasing traffic demand every year and to solve many traffic problems. Especially, Advanced Traveller Information System(ATIS) is a transportation system to optimize the trip of each other vehicle. It is important to provide the driver with quick and comfortable path from source to destination. However, it is difficult to provide a shortest path in a road network with dynamic cost. Because the existing research has a static cost. Therefore, in this paper we propose an operator for searching traffic dependent shortest path. The proposed operator finds the shortest path from source to destination using a current time cost and a difference cost of past time cost. Such a method can be applied to the road status with time. Also, we can expect a predicted arrival time as well as the shortest path from source to destination. It can be applied to efficiently application service as ITS and have the advantages of using the road efficiently, reducing the distribution cost, preparing an emergency quickly, reducing the trip time, and reducing an environmental pollution owing to the saving the fuel.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2843-2845
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• 2000

A lane detection based on a road model or feature all need correct acquirement of information on the lane in a image, It is inefficient to implement a lane detection algorithm through the full range of a image when being applied to a real road in real time because of the calculating time. This paper defines two searching range of detecting lane in a road, First is searching mode that is searching the lane without any prior information of a road, Second is recognition mode, which is able to reduce the size and change the position of a searching range by predicting the position of a lane through the acquired information in a previous frame. It is allow to extract accurately and efficiently the edge candidates points of a lane as not conducting an unnecessary searching. By means of removing the perspective effect of the edge candidate points which are acquired by using the inverse perspective transformation, we transform the edge candidate information in the Image Coordinate System(ICS) into the plane-view image in the World Coordinate System(WCS). We define linear approximation filter and remove the fault edge candidate points by using it This paper aims to approximate more correctly the lane of an actual road by applying the least-mean square method with the fault-removed edge information for curve fitting.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1998년도 학술발표대회 논문집 제17권 1호
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• pp.155-158
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• 1998

IMBE(Improved Multi-Band Excitation) vocoders exhibit good performance at low data rates. The major drawback to IMBE coders is their large computational requirements. In this paper, thus, we propose a new pitch search method that preserves the quality of the IMBE vocoder with reduced complexity. The basic idea is to reduce computation complexity of the pitch searching by using the SAMDF. Applying the proposed method to the IMBE vocoder, we can get approximately 52.02% searching time reduction in the pitch search. There is no difference in voice quality between conventional IMBE and proposed IMBE.

• 한국경영과학회지
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• 제8권1호
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• pp.11-18
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• 1983

This paper shows a new efficient solution method of finding an optimal path for a cruise missile or aircraft to a target which has the maximal survivability and penetration effectiveness against sophisticated defenses and over varied terrain. We first generate a grid structure over the terrain, to construct a network. Since our network usually has about 10,000 nodes, the conventional Dijkstra algorithm takes too much computational time in its searching process for a new permanent node. Our method utilizes the Hashing technique to reduce the computational time of the searching process. Extensive computational results are presented.

• 산업경영시스템학회지
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• 제38권4호
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• pp.11-21
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• 2015

In order to achieve success in ground operations, searching for moving targets is one of critical factors. Usually, the system of searching for adversary ground moving targets has complex properties which includes target's moving characteristics, camouflage level, terrain, weather, available search time window, distance between target and searcher, moving speed, target's tactics, etc. The purpose of this paper is to present a practical quantitative method for effectively searching for infiltrated moving targets considering aforementioned complex properties. Based upon search theories, this paper consists of two parts. One is infiltration route analysis, through terrain and mobility analysis. The other is building dynamic probability maps through Monte Carlo simulation to determine the prioritized searching area for moving targets. This study primarily considers ground moving targets' moving pattern. These move by foot and because terrain has a great effect on the target's movement, they generally travel along a constrained path. With the ideas based on the terrain's effect, this study deliberately performed terrain and mobility analysis and built a constrained path. In addition, dynamic probability maps taking terrain condition and a target's moving speed into consideration is proposed. This analysis is considerably distinct from other existing studies using supposed transition probability for searching moving targets. A case study is performed to validate the effectiveness and usefulness of our methodology. Also, this study suggests that the proposed approach can be used for searching for infiltrated ground moving target within critical time window. The proposed method could be used not only to assist a searcher's mission planning, but also to support the tactical commander's timely decision making ability and ensure the operations' success.