• Proceedings of the KSRS Conference
• /
• 2006.03a
• /
• pp.311-314
• /
• 2006

본 연구에서는 서로 다른 센서간의 영상 자료 융합을 위하여 Dempster-Shafer 기법을 제안하고 있다. 제안 된 Dempster-Shafer 기법은 불확실성의 최소 값을 대표하는 Belief 함수와 불확실성의 최대 값을 나타내는 Plausibility 함수를 사용한다. 이러한 두 함수의 차이는 Belief Interval 로 정의되며 이 값은 분석 대상에 존재하는 불확실 정도의 Measure 로 사용되며 Evidence Combination의 이론에 근거하여 서로 다른 센서간의 자료 융합이 가능하며 분류 결과로 클래스 맵 뿐 만 아니라 분류 결과에 대한 불확실성 정도를 나타내는 Belief 함수 값과 Plausibility 함수 값을 생성하여 분류 결과에 대한 보충적인 분석을 가능하게 하여 사용자의 분석 정확성을 증대 시킬 수 있다.

• Journal of Broadcast Engineering
• /
• v.3 no.1
• /
• pp.85-92
• /
• 1998

The block matching algorithm is the most popular motion estimation method in image sequence coding. In this paper, we propose a VLSI architecture. for implementing a recently proposed fast bolck matching algorith, which uses spatial correlation of motion vectors and hierarchical searching scheme. The proposed architecture consists of a basic searching unit based on a systolic array and two shift register arrays. And it covers a search range of -32~ +31. By using the basic searching unit repeatedly, it reduces the number of gatyes for implementation. For basic searching unit implementation, a proper systolic array can be selected among various conventional ones by trading-off between speed and hardware cost. In this paper, a structure is selected as the basic searching unit so that the hardware cost can be minimized. The proposed overall architecture is fast enough for low bit-rate applications (frame size of $352{\times}288$, 3Oframes/sec) and can be implemented by less than 20,000 gates. Moreover, by simply modifying the basic searching unit, the architecture can be used for the higher bit-rate application of the frame size of $720{\times}480$ and 30 frames/sec.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.46 no.10
• /
• pp.40-45
• /
• 2009

In this paper, we introduce a mobile-type tiny sensor device that can classify the activities of daily living based on the state-dependent motion analysis using a 3-axial accelerometer in real-time. The device consists of an accelerometer, GPS module, 32bit micro-controller for sensor data processing and activity classification, and a bluetooth module for wireless data communication. The size of device is 50*47*14(mm) and lasts about 10 hours in operation-mode and 160 hours in stand-by mode. Up to now, the device can recognize three user activities ("Upright", "Running", "Walking") based on the decision tree. This tree is constructed by the pre-learning process to activities of subjects. The accuracy rate of recognizing activities is over 90% for various subjects.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2014.06a
• /
• pp.226-229
• /
• 2014

본 논문은 효과적인 열화영상의 복원을 위해 Multiresolution Bilateral Filter (MBF) 기반의 구간적 노이즈 분석을 제안한다. 기존의 MBF 알고리즘은 최적화되지 않은 노이즈 추정 값을 중첩적으로 사용하다보니 over smoothing 현상이 발생되는 결과가 도출되기도 하였다. 이에 따른 보완점으로 열화영상 내 전체 화소를 일정한 블록 단위의 영역으로 나누어, 영상특성을 최대한 보존하며 노이즈제거를 진행하기 위해 블록 단위의 영역 내에서 노이즈 추정을 위한 파라미터를 추가한다. 실험을 통해 제안된 알고리즘이 노이즈 추정을 수행하여 얻어진 노이즈의 분산 값을 보다 정확히 추정하였고, 이로 인하여 향상된 노이즈 제거 영상 획득이 가능함을 확인할 수 있었다.

• Proceedings of the Korean Statistical Society Conference
• /
• 2004.11a
• /
• pp.135-140
• /
• 2004

Lindsay and Basu (1994)에 의해 소개된 최소차이추정량 (Minimum Disparity Estimators)들은 실제 자료 분석 도구로써 유용하다. 본 논문에서는 최소일반화음지수 차이추정량 (Minimum Generalized Negative Exponential Disparity Estimator, MGNEDE)이 최대가능도추정량 (Maximum Likelihood Estimator, MLE)와 최소가중 헬링거거리추정량 (Minimum Blended Weight Hellinger Distance Estimator, MBWHDE)에 비해 오염된 정규모형에서 효율적이고 로버스트하다는 것을 모의실험을 통하여 확인하였다. 또한 세 가지 추정량들에 의해 추정된 모수들을 이용하여 판별하였을 때 자 추정량득의 판별율을 비교함으로써 오염된 정규모형에서 MLE의 대안으로 MGNEDE와 MBWHDE를 사용할 수 있음을 보였다.

• Journal of KIISE:Databases
• /
• v.34 no.5
• /
• pp.379-388
• /
• 2007

Disordered streams may cause inaccurate or delayed results in window-based queries. Existing approaches usually leverage buffers to hand]e the streams. However, most of the approaches estimate the buffer size simply based on the maximum network delay in the streams, which tends to over-estimate the buffer size and result in high latency. In this paper, we propose a probabilistic approach to estimate the buffer size adaptively according to the fluctuated network delays. We first assume that intervals of tuple generations follow an exponential distribution and network delays have a normal distribution. Then, we derive an estimation function from the assumptions. The function takes a drop ratio as an input parameter, which denotes a percentage of tuple drops permissible during query execution. By describing the drop ratio in a query specification, users can control the quality of query results such as accuracy or latency according to application requirements. Our experimental results show that the proposed function has better adaptivity than the existing function based on the maximum network delay.

• Journal of Korea Water Resources Association
• /
• v.49 no.2
• /
• pp.107-119
• /
• 2016

Since future climate scenarios indicate that extreme precipitation events will intensity, probable maximum precipitations (PMPs) without being taken climate change into account are very likely to be underestimated. In this study future PMPs in accordance with the variation of future rainfall are estimated. The hydro-meteorologic method is used to calculate PMPs. The orographic transposition factor is applied in place of the conventional terrain impact factor which has been used in previous PMPs estimation reports. Future DADs are indirectly obtained by using bias-correction and moving-averaged changing factor method based on daily precipitation projection under KMA RCM (HEDGEM3-RA) RCP 8.5 climate change scenario. As a result, future PMPs were found to increase and the spatially-averaged annual PMPs increase rate in 4-hour and $25km^2$ was projected to be 3 mm by 2045. In addition, the increased rate of future PMPs is growing increasingly in the future, but it is thought that the uncertainty of estimating PMPs caused by future precipitation projections is also increased in the distant future.

• Proceedings of the KAIS Fall Conference
• /
• 2008.05a
• /
• pp.248-250
• /
• 2008

This paper proposes a prediction method to prevent traffic accident and reduce to vehicle waiting time using neural network. Computer simulation results proved reducing average vehicle waiting time which proposed coordinating green time better than electro-sensitive traffic light system dose not consider coordinating green time. Moreover, we present neural network approach for traffic accident prediction with unnormalized (actual or original collected) data. This approach is not consider the maximum value of data and possible use the network without normalizing but the predictive accuracy is better. Also, the unnormalized method shows better predictive accuracy than the normalized method given by maximum value. Therefore, we can make the best use of this model in software reliability prediction using unnormalized data. Computer simulation results proved reducing traffic accident waiting time which proposed neural network better than conventional system dosen't consider neural network.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.12 no.5
• /
• pp.755-764
• /
• 2001

In this paper, we propose maximum likelihood (ML) decision feedback channel estimation (DFCE) for M-ary orthogonal modulation in direct sequence/code division multiple access (DS/CDMA) systems. The proposed DFCE uses the maximum combiner output in a RAKE receiver as decision feedback information, enabling M-ary orthogonal signals to be demodulated coherently and a RAKE receiver to use a em maximal ration combining (MRC) scheme. However, the performance of the proposed DFCE in the multiuser environment is severely degraded due to multiple access interference (MAI). To overcome this problem, a multistage parallel interference cancellation (PIC) scheme is combined with the proposed DFCE for multiuser environments. Accurate knowledge of the channel coefficient estimated by the proposed DFCE is used to regenerate the signal of each user for the multistage PIC scheme. According to the results of our simulations, the performance of coherent demodulation using the proposed system is significantly improved in comparison with conventional noncoherent demodulation.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2010.11a
• /
• pp.257-259
• /
• 2010

본 논문에서는 지상파 3D HDTV 방송 서비스를 제공하기 위해 수정된 ATSC (Advanced Television Systems Committee) 전송 시스템 [2]을 위한 시변다중경로채널에 강인한 프레임 구조를 제안하고 성능을 측정하였다. 수정된 ATSC 전송 시스템 [2]은 기존 ATSC 전송 시스템[1]의 채널 부호화부를 수정하고, 변조 성상도를 증가 시키면서 적정한 수준의 TOV (Threshold of Visibility)에서의 전송 용량 증대 가능성을 확인하였다. 이를 토대로, 증가된 전송 데이터 전송률에 대한 순수 데이터 전송률을 최대한 보장하면서 시변다중경로채널에서 효율적으로 채널을 추정하고 복구하기 위해, ISI (Inter Symbol Interference)를 방지하기 위한 프레임 헤더의 보호구간에 알려진 PN (Pseudorandom Noise) 심벌을 삽입하였다. PN 심벌을 보호 구간에 이용할 경우 시간 영역에서 채널 임펄스 응답 (CIR: Channel Impulse Response)을 추정하여, 주파수 영역에서의 채널 보상을 가능케 하여 정확한 채널 추정 및 보상을 수행할 수 있다. 또한 수신기의 속도에 따른 다양한 최대 도플러 주파수가 존재하는 채널에 강인한 프레임 구조들을 제안하였다. 컴퓨터 시뮬레이션을 통해 수정된 ATSC 전송 시스템에 제안된 프레임 구조를 적용하여 TU (Typical Urban)-6 채널에서의 SER (Symbol Error Rate) 성능을 측정하였다.