• 대한전자공학회논문지SP
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• 제40권5호
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• pp.417-425
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• 2003

ITU-T(International Telecommunication Union-Telecommunication standardization sector)와 MPEG(Moving Picture Experts Group)에 의해서 최근 표준화가 완성된 H.264는 가변 블록 크기 움직임 추정, 복수참조영상, 1/4화소 움직임 예측/보상, 4×4 정수 DCT(Integer Discrete Cosine Transform), 율-왜곡 최적화(Rate-Distortion Optimization) 등의 새로운 부호화 기술로 H.263, MPEG-4 등 기존 비디오 표준에 비해 더 좋은 부호화 효율을 제공하고 있다. 그러나 새로운 부호화 기술들은 H.264 의 전반적인 복잡도를 심화시키는 주된 요인이기도 하다. 따라서, H.254 의 실제 응용을 용이하게 하기 위해서는 이러한 기술에 대한 고속 알고리즘이 요구된다. 본 논문에서는 율-왜곡 최적화를 통한 부호화 모드 결정시 부호화기의 복잡도에서 가장 큰 비중을 차지하는 가변 블록 크기 움직임 추정 및 공간예측 부호화를 효율적으로 생략하여 부호화 모드 결정을 빠르게 수행하는 고속 모드 결정법을 제안한다. 실험결과, 제안된 방법은 부호화 효율의 손실이 거의 없으면서도 계산법을 약 4배 향상시킨다.

• 한국컴퓨터정보학회논문지
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• 제16권4호
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• pp.73-81
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• 2011

본 논문에서는 모델 히스토그램 개수를 적응적으로 조절하는 블록기반의 배경 모델링 방법을 제안한다. 기존의 블록 기반의 배경 모델링 방법은 각 블록에 대한 모델 히스토그램의 개수를 고정한다. 따라서 조명변화와 움직이는 객체에 대해 오검출이 발생하는 문제가 있고 움직임이 없는 객체에 대해서는 검출이 되지 않는 문제가 있다. 또한 입력영상의 종류마다 달라질 수 있는 최적의 모델 히스토그램의 개수를 수동적으로 찾아야 하는 문제가 있다. 본 논문에서는 실험을 통해 엘리베이터 내에서 조명변화가 있고 객체가 움직이는 상황과 조명변화가 없고 객체가 정지해 있는 상황에 대해 기존의 방법과 성능을 비교하여 제안한 알고리즘의 효용성을 입증한다.

• 한국항해항만학회지
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• 제29권1호
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• pp.83-90
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• 2005

블록 내 이적이란 컨테이너를 선박에 싣는 적하 작업을 효율적으로 수행하기 위하여 하나의 장치장 블록 여기저기에 흩어져 있는 컨테이너들을 적하 순서에 맞춰 몇 개의 베이로 모으는 작업이다. 이전시 적하 순서를 고려하지 않고 단순히 컨테이너들을 모으기만 하면, 적하 작업 과정에서 보다 일찍 적하될 컨테이너를 반출하기 위하여 상단의 컨테이너들을 임시로 옮겨야 하는 재취급이 빈번히 발생할 수 있다. 이러한 재취급은 적하 작업의 효율을 저해하는 가장 중요한 요소 중의 하나이다. 본 논문에서는 휴리스틱을 이용하여 적하 작업 과정에서 재취급이 발생하지 않게 컨테이너들을 이적할 수 있는 컨테이너 이동 순서를 찾는 방안을 제안한다. 시뮬레이션을 통한 실험 결과 본 제안 방안이 다양한 환경에서 컨테이너 이동 순서를 실시간에 생성할 수 있음을 확인하였다.

• 한국지능시스템학회논문지
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• 제21권1호
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• pp.106-111
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• 2011

영상 기반의 움직이는 객체의 검출 및 추적은 실시간 감시 시스템이나 영상회의 시스템 등에서 널리 사용되어지고 있다. 또한 인간-컴퓨터 상호 작용(Human-Computer Interface)이나 인간-로봇 상호 작용(Human-Robot Interface)으로 확장되어 사용할 수 있기 때문에 움직이는 객체의 추적 기술은 중요한 핵심 기술 중에 하나이다. 특히 다중 객체의 움직임 환경에서 특정 객체의 움직임만을 추적할 수 있다면 다양한 응용이 가능할 것이다. 본 논문에서는 파티클 필터를 이용한 특정 객체의 움직임 추적에 관하여 연구 하였다. 실험 결과들로부터 파티클 필터를 이용한 단일 객체의 움직임 추적과 다중 객체의 움직임 환경에서 특정 객체의 움직임 추적에서 좋은 결과를 얻을 수 있었다.

• 대한조선학회논문집
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• 제54권5호
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• pp.421-429
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• 2017

It is very important to manage the position of the blocks in the shipyard where the work is completed, or the blocks need to be moved for the next process operation. The moving distance of the block increases according to the position of the block stockyard. As the travel distance increases, the number of trips and travel distance of the transporter increases, which causes a great deal of operation cost. Currently, the selection of the block position in the shipyard is based on the know-how of picking up a transporter worker by the production schedule of the block, and the location where the block is to be placed is determined according to the situation in the stockyard. The know-how to select the position of the block is the result of optimizing the position of the block in the shipyard for a long time. In this study, we used the accumulated data as a result of the operation of the yard in the shipyard and tried to select the location of blocks by learning it. Decision tree learning algorithm was used for learning, and a prototype was developed using it. Finally, we prove the possibility of selecting a block stockyard through this algorithm.

• ETRI Journal
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• 제23권4호
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• pp.190-198
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• 2001

The performance of Motion Compensated Discrete Cosine Transform (MC-DCT) video coding is improved by using the region adaptive subband image coding [18]. On the assumption that the video is acquired from the camera on a moving platform and the distance between the camera and the scene is large enough, both the motion of camera and the motion of moving objects in a frame are compensated. For the compensation of camera motion, a feature matching algorithm is employed. Several feature points extracted using a Sobel operator are used to compensate the camera motion of translation, rotation, and zoom. The illumination change between frames is also compensated. Motion compensated frame differences are divided into three regions called stationary background, moving objects, and newly emerging areas each of which is arbitrarily shaped. Different quantizers are used for different regions. Compared to the conventional MC-DCT video coding using block matching algorithm, our video coding scheme shows about 1.0-dB improvements on average for the experimental video samples.

• 전자공학회논문지B
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• 제31B권8호
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• pp.129-136
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• 1994

In this paper an adaptive moving method of the search region tracking the motion is proposed. The search region in BMA is determined by the capability of hardware implementation and the degree of motion. But once determined nothing can be changed during coding procedure. In this paper we predict the level of motion of the current block using motion vectors of previous frames without overhead information and change the location of the search region according to the level of the motion predicted. In short the proposed method can be archieved the dsirable effect such that the size of search region gets large when the motion is large. Results of experiments show that prediction efficiency has been improved by using adaptive moving method resulting in reduced prediction error in the blocks with large motion.

• 한국통신학회논문지
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• 제21권6호
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• pp.1361-1369
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• 1996

Motion estimation is one of the key components for high quality video coding. In this paper, a new motion estimation scheme for MPEG-like video coder is suggested. The proposed temporally adaptive motion estimation scheme consists of five functional blocks: Temporal subband analysis (TSBA), extraction of temporal information, scene change detection (SCD), picture type replacement (PTR), and temporally adapted block matching algorithm (TABMA). Here all the functional components are based on the temporal subband analysis. In this papre, we applied the analysis part of subband decompostion to the temporal axis of moving picture sequence, newly defined the temporal activity distribution (TAD) and average TAD, and proposed the temporally adapted block matching algorithm, the scene change detection algorithm and picture type replacement algorithm which employed the results of the temporal subband analysis. A new block matching algorithm TABMA is capable of controlling the block matching area. According to the temporal activity distribution of objects, it allocates the search areas nonuniformly. The proposed SCD and PTR can prevent unavailable motion prediction for abrupt scene changes. Computer simulation results show that the proposed motion estimation scheme improve the quality of reconstructed sequence and reduces the number of block matching trials to 40% of the numbers of trials in conventional methods. The TSBA based scene change detection algorithm can detect the abruptly changed scenes in the intentionally combined sequence of this experiment without additional computations.

• 전자공학회논문지B
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• 제30B권1호
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• pp.45-55
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• 1993

In this paper, a two-stage block matching algorithm (BMA), which can reduce greatly the computational complexity of the conventional BMAs, is proposed, in which the onedimensional distortion measure based on the integral projection is introduced to determine the candidate motion vectors and then among them a final motion vector is detected based on the conventional two-dimensional distortion measure. Due to the one-dimensional calculation of a distortion measure, the proposed algorithm can reduce the computational complexity of the conventional BMA (full search method with a 16$\times$16 block) by a factor of 4, with its performance comparable to those of the conventional ones. Simulation results based on the original and noisy image sequences are shown. Also the simulation of the proposed method combined with the MPEG (Moving Picture Experts Group) SM3 (Simulation Model Three) is presented. Computer simulation shows that the proposed algorithm is fast with its performance comparable to those of the conventional ones.

• The Journal of the Acoustical Society of Korea
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• 제27권1E호
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• pp.17-24
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• 2008

Blind speech separation (BSS) is well-known as a powerful technique for speech enhancement in many real world environments. In this paper, we propose a new application of BSS - acoustic echo cancellation (AEC) in a car environment. For this purpose, we develop a block-online BSS algorithm which provides robust separation than a batch version in changing environments with moving speakers. Simulation results using real world recordings show that the block-online BSS algorithm is very robust to speaker movement. When combined with AEC, simulation results using real audio recording in a car confirm the expectation that BSS improves double talk detection and echo suppression.