• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.9 no.2
• /
• pp.338-347
• /
• 2005

In this paper, a decimation-in-time search direction algorithm for displacement prediction of moving object is proposed. The initialization of the proposed algorithm for moving direction prediction is performed by detecting moving objects at sequential frames and by obtaining a moving angle and a moving distance. A moving direction of the moving object at current frame is obtained by applying the decimation-in-time search direction mask. The decimation-in-tine search direction mask is that the moving object is detected by thinning out frames among the sequential frames, and the moving direction of the moving object is predicted by the search mask which is decided by obtaining the moving angle of the moving object in the 8 directions. to examine the propriety of the proposed algorithm, velocities of a driving car are measured and tracked, and to evaluate the efficiency, the proposed algorithm is compared to the full search algorithm. The evaluated results show that the number of displacement search times is reduced up to 91.8$\%$ on the average in the proposed algorithm, and the processing time of the tracking is 32.1ms on the average.

• Journal of Advanced Navigation Technology
• /
• v.4 no.1
• /
• pp.67-77
• /
• 2000

This paper proposes a reduction scheme for codebook search time in the adaptive codebook using wavelet transformed coefficients. In a CELP coder, pitch estimation with a combined open loop and closed loop search in adaptive codebook needs a lengthy search. More precisely, the pitch search using autocorrelation function over all possible ranges has been shown inefficient compared to the consuming time. In this paper, we propose a new adaptive codebook search algorithm which ensures the same position for the pitch with maximum wavelet coefficient over various scaling factors in Dyadic wavelet transform. A new adaptive codebook search algorithm reduces 25% conventional search time with almost the same quality of speech.

• The Journal of the Convergence on Culture Technology
• /
• v.9 no.5
• /
• pp.159-165
• /
• 2023

This study was limited to the underwater search part among water accidents on the inland water surface, and analyzed five underwater search methods and lifesaving time at 5m underwater. The subjects of the experiment were 10 people. The semi-circle search took the longest with 259 seconds, and the modified round-trip search took 78.60 seconds, showing a significant difference with an average of 180.04 seconds. Subjects B and D showed similar values, with average underwater search times of 199 seconds and 202 seconds, respectively. Subject C showed a significantly higher average underwater search time of 209 seconds. The reason seems to be from increased anxiety and excessive tension due to poor underwater watch. Subject A showed a significantly lower underwater search time of 187 seconds. The reason seems to be the result of E's experience being the most among the test subjects and his rich diving experience in the Han River with poor visibility. As for convenience, semicircle search showed a low score of 6~7, and modified reciprocal search showed a high score of 8~9. The most suitable rescue method as an underwater search method in the Han River where visibility is poor is determined to be a modified round-trip search method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.23 no.6
• /
• pp.740-747
• /
• 2012

An Active Electronically Scanned Array(AESA) radar required necessarily as the Fire Control Radar(FCR) of recent fighters has ununiform detection range with regard to scan angle due to scan loss. Although the compensation method of scan loss in an AESA radar with variable dwell time is investigated, the effectiveness of the method in a fighter FCR with multi-function such as search, track, and missile guidance within limited resources should be considered systematically. In this paper, uniform search performance of an AESA radar using variable dwell time with regard to scan angle is derived. We assumed the search load of 50 % for case without changing dwell time in fixed frame time and showed the fighter FCR requirement for multi-function is not satisfied because the search load for the uniform search performance should be increased by about 100 %. On the other hand, in case of increasing the frame time for the uniform search performance and search load of 50 %, degradation of the search performance is shown by 86.7 % compared with the former. Based on these analyses, the effective beam operation strategy on an airborne AESA radar with uniform search performance in whole scan area is described with consideration of frame time, search load and performance as a whole.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.1B
• /
• pp.24-33
• /
• 2002

The cell search scheme for W-CDMA consists of the following three stages: slot synchronization(1st stage), group identification and frame boundary detection(2nd stage), and long code identification(3rd stage). The performance of the cell search when a mobile station is switched on, which is referred to as initial cell search, is decreased by the initial frequency and timing error. In this paper, we propose the pipeline structured initial cell search scheme using time trackers to compensate for the impact of the initial timing error in the stage 2 and stage 3. The simulation results show that the performance of the proposed scheme is maximal 1.5dB better than that of the conventional one when the initial timing error is near ${\pm}T_c$/2.

• Proceedings of the KIEE Conference
• /
• 2005.07d
• /
• pp.2918-2920
• /
• 2005

본 논문에서는 네비게이션 시스템 사용 시 교통 체증 등의 상황이 발생하여 최적 경로를 따라 가는 경우의 소요시간이 실제 예상시간보다 크게 증가하게 되는 경우 주변의 샛길을 이용하여 보다 빠른 시간에 체증 구간을 회피하여 목적지에 도착 할 수 있게 하는 알고리즘을 제안하고 이를 항법서버에 구현한다. 교통 체증상황이 발생하는 경우 경로 탐색시의 각 길에 대한 weighting 을 조절함으로써 원래 최적경로와 다른 우회로를 찾아 낼 수 있도록 한다. 상용화 되어있는 네비게이션 단말기를 사용하였으며 PC 시뮬레이터와 개발 서버를 이용하여 샛길 탐색 기능을 구현하였다. 최적경로 탐색에는 A* 알고리즘을 응용하였으며 최적경로에서 샛길 탐색구간을 구하여 전체 경로를 탐색하는 알고리즘을 구현하였다.

• Journal of the Korean Society for Library and Information Science
• /
• v.31 no.3
• /
• pp.209-237
• /
• 1997

The main purpose of this study is to find the difference of information searching behaviours consist of information pursuit cognition and searching character by time pressure of researchers. The majar findings and result by time pressure of researchers are summarized as follows : In terms of information retrieval systems, according to the time pressure, there is a significant difference in recall, precision and diversity. In terms of main used material, there is a significant difference in a book, a research report, and a Journal. In terms of resource types, there is a significant difference in both record and human resource. Also, in terms of searching behaviours, there is a difference to spend time for information collection and information searching strategy, and to decide information searching method and degree of searching.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37 no.2A
• /
• pp.113-118
• /
• 2012

In this paper, we propose the removal of search point using motion vector correlation and distance between reference frames in H.264/AVC. We remove the search points in full search method and predictive motion vectors in enhanced predictive zonal search method. Since the probability that the reference frame far from the current frame is selected as the best reference frame is decreased, we apply the weighted average based on distance between the current and reference frame to determine the fianl search range. In general, the size of search range is smaller than initial search range. We reduce motion estimation time using the final search range in full search method. Also, the refinement process is adaptively applied to each reference frame. The proposed methods reduce the computational throughput of full search method by 57.13% and of enhanced predictive zonal search by 14.71% without visible performance degradation.

• Proceedings of the Korean Information Science Society Conference
• /
• 2005.11b
• /
• pp.145-147
• /
• 2005

최근 들어 저장장치의 발전과 네트워크의 발달로 인하여 대용량의 데이터가 매우 빠르게 증가되고 있다. 또한, 대용량의 데이터에 내재되어 있는 정보를 빠른 시간 내에 처리하여 새로운 지식을 창출하려는 요구가 증가하고 있다. 연속적이고 빠르게 증가하는 데이터를 지칭하는 데이터 스트림에서 데이터 마이닝 기법을 이용하여 시간이 흐름에 따라 변하고, 무한적으로 증가하는 데이터 스트림에서의 빈발항목을 찾는 연구가 활발하게 진행되고 있다. 하지만 기존의 연구들은 시간의 흐름에 따른 빈발항목 탐색방법을 적절히 제시하지 못하고 있으며 단지 집계를 이용하여 빈발항목을 탐색하고 있다. 본 논문에서는 데이터 스트림에서 시간적 측면을 고려하여 상대적인 빈발항목을 탐색하기 위한 새로운 알고리즘을 제안한다. 논문에서 제안하는 알고리즘의 성능은 다양한 실험을 통해서 검증된다.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2023.01a
• /
• pp.361-364
• /
• 2023

볼륨 렌더링은 3D 밀도 데이터를 가시화 할 때 활용되는 기술로써 이 알고리즘에서 중요한 것은 렌더링 시간 단축이며, 본 논문에서는 이 계산시간을 효율적으로 개선시킬 수 있는 방법을 제시한다. 렌더링의 처리시간은 탐색하는 횟수에 따라 결과 차이가 발생하지만, 탐색 횟수가 적을 경우 렌더링의 품질이 저하되고 반대인 경우에는 화질의 표현력은 높으나 많은 처리시간이 소요된다. 따라서 화질이 떨어지지 않는 최소의 탐색 방법이 요구되므로 본 논문에서는 밀도의 탐색 최적화와 시간별 밀도가 존재하는 위치를 예측하여 계산을 효율적으로 처리 할 수 있는 PyCUDA 프레임워크에 대해서 소개한다.