• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.744-749
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• 2007

물체 추적시스템은 비디오 감시 시스템, 화상회의 시스템과 같은 다양한 비전 응용 분야에서 점점 비중이 높아지고 있다. 이 시스템에서 가장 널리 사용되고 있는 방법 중 하나로 Particle-Filter를 들 수 있다. 하지만, 이 Particle-Filter의 단점은 유사한 여러 물체를 추적할 때에 그 물체들이 겹치거나 사라질 경우 정확한 추적을 하기 어렵다는 것이다. 이 단점을 극복하기 위해 많은 연구가 진행되고 있으며, 본 논문에서는 이 문제를 극복하기 위한 새로운 방법을 제안하고자 한다. 다중 물체 추적에서 빈번히 일어나는 문제는 두 가지로 요약할 수 있는데, 동일한 다중 물체가 부분적으로 엇갈리거나 다른 객체에 완전히 겹친 후 떨어질 때 한 물체를 중복하여 추적하는 문제(merge and split problem)와 이 때 분리되어 추적은 됐지만, 물체를 혼동하여 추적하는 문제(Labeling problem)이다. 본 논문에서는 이 러한 문제들을 풀기 위해 이미지 필드에서 보다 정확한 확률분포를 만들고, 이 확률분포의 신뢰성을 높이기 위해서 물체의 특징정보를 표현하는 몇 가지 방법을 제안한다. 전자의 문제는 두 가지 문제로 나누어 생각해 보았다. 첫째, 복잡환 환경에서의 분포를 찾아내는 것과 둘째, 추적 중인 물체를 잃어버릴 경우 새로운 샘플을 생성함으로써 나누어 보았다. 이 문제 중 첫번째는 K-means 클러스터링을 이용하여 유사한 물체가 주변에 퍼져 있을 때, 하나의 후보 위치가 아닌, K개의 후보 위치들을 만들어 내어 보다 정확한 추적이 가능하게 하였으며, 두 번째 문제는 추적 중인 물체가 다른 커다란 물체에 가려질 경우이다. 이 상황에서 샘플을 생성하는 방법은 지금까지 해왔던 간단한 환경에서의 생성 범위와는 다르게 넓게 해야 생성시켜야 한다. 이 때 샘플링의 수를 늘리지 않으면서, 최대한 정확하게 추적하기 위해서 동영상에서 물체의 모션을 이용한 모션 히스토그램을 얻어내고, 그 정보를 이용하여 샘플을 생성하는 위치를 조절함으로써 이 문제를 풀어 보았다. 그리고, 후자의 문제인 이미지 필드상에서 확률분포의 신뢰성을 높이기 위한 특징 정보는 기존에 많이 사용하던 칼라 히스토그램에 공간정보의 의미를 부여하는 칼라 히스토그램을 분할하는 방법과 SIFT에서 사용하는 방향정보와 크기정보를 사용했다. 이것들을 사용하여 보다 정확한 물체추적시스템을 다음과 같이 제안한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.6
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• pp.1229-1235
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• 2003

When finite length image signal is decomposed into 2-band signal and synthesized using 2-band orthogonal wavelet transform, boundary signals are not reconstructed perfectly. To reconstruct them perfectly, the filters which are different from wavelet filter are applied to the boundary signals. Since the existing boundary filters show poor frequency characteristic, the improvement of performance is bounded in practical applications. In this paper, the design method of improvement of frequency characteristic is proposed using inserting a zero to boundary filters which can reconstruct the boundary regions perfectly. Even though the length of proposed boundary filters is shorter, they show 4.2dB∼6.59dB gains in pass band and stop band error power compared with existing boundary filters. But synthesis process is some complicated.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.8
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• pp.1675-1685
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• 2012

DVC (Distributed Video Coding) technique plays an essential role in providing low-complexity video encoder. But, in order to achieve the better rate-distortion performances, most DVC systems need feedback channel for parity bit control. This causes the DVC-based system to have high decoding latency and becomes as one of the most critical problems to overcome for a real implementation. In order to overcome this problem and to accelerate the commercialization of the DVC applications, this paper analyzes an effect of LDPCA frame size for adaptive LDPCA frame-based parity bit request estimations. First, this paper presents the LDPCA segmentation method in pixel-domain and explains the temporal-based bit request estimation method and the spatial-based bit request estimation method using the statistical characteristics between adjacent LDPCA frames. Through computer simulations, it is shown that the better performance and fast decoding is observed specially when the LDPCA frame size is 3168 in QCIF resolution.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.4
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• pp.767-773
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• 2017

In this paper, we propose a design of Intra prediction angular mode decision for HEVC encoder. Intra prediction coding of HEVC is a method for predicting a current block by referring to samples reconstructed around a current block. Intra prediction supports a total of 35 modes with 1 DC mode, 1 Planar mode, and 33 Angular modes. Intra prediction coding of HEVC works by performing all 35 modes for efficient encoding. However, in order to process all of the 35 modes, the computational complexity and operational time required are high. Therefore, this paper proposes comparing the difference in the value of the original pixel, using an algorithm that determines angular mode efficiently. This new algorithm reduces the Hardware size. The hardware which is proposed was designed using Verilog HDL and was implemented in 65nm technology. Its gate count is 14.9K and operating speed is 2GHz.

• 한국HCI학회:학술대회논문집
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• 2007.02b
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• pp.7-14
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• 2007

디지털 컨버전스가 가속화됨에 따라 휴대폰의 기능은 나날이 복잡해져 가고 있으며, 이러한 경향은 사람들에게 자신에게 불필요한 기능까지 익혀야 하는 불편함을 초래하고 있다, 특히, 단순한 통화방식에 익숙하고 인지적으로 새로운 것을 유연하게 받아들이지 못하는 고령 사용자들에게도 이미 생활필수품이 된 휴대폰은 사용하는데 어렵고 불편한 부분이 많이 있다. 본 연구에서는 한국의 고령사용자들을 대상으로 휴대폰 사용에 있어 문맥적, 정성적 조사(Contextual & Qualitative research)기법을 적용하여 평소 그들이 일상생활에서 느끼는 휴대폰 관련 요구사항을 도출하고자 하였다. 조사는 세 단계로 이루어졌다. 먼저, 휴대폰을 사용 중인 60대 이상 고령사용자 83명을 대상으로 사용 현황 및 수준을 파악하고 적절한 사용자를 섭외하기 위한 설문을 진행하였으며, 둘째, 초보사용자 8명, 중급사용자 3명을 대상으로 휴대폰 사용 기록을 기반으로 하는 심층인터뷰를 진행하였으며, 초보사용자들을 대상으로는 문자메세지, 전화번호부, 카메라 폰 기능 교육 세션을 통한 행동 관찰법을 시행하였다. 마지막으로, 교육 세션 한달 후, 사용성 평가와 추가 인터뷰를 진행하였다. 이상과 같이 장기간에 걸친 사용자 조사를 통해, 고령사용자들의 휴대폰 사용에 있어 심리, 문화적 특이사항과 인터랙션 상의 불편요소들을 발견할 수 있었으며, 수집된 동영상 데이터를 분석하여 고령사용자의 휴대폰 관련 요구사항을 신체적 요인, 인지적요인, 심리적 요인의 세가지로 구분하여 제시하였다. 본 연구에서는 문맥적, 정성적 사용자 조사를 통해 고령사용자들의 일상생활에서의 휴대폰 관련 요구사항을 도출함으로써 풍부하고 실증적인 경험데이터를 수집할 수 있었다. 이와 같이 도출된 요구사항 데이터는 이후 고령사용자를 위한 유니버설 디자인 휴대폰 개발 전략수립과 UI 디자인 개발에 활용되었다. 뿐만 아니라, 이 연구는 휴대폰 사용 경험 연구에 적용할 수 있는 문맥적 조사기법 프로세스의 사례를 제시하고 있다는데 의의가 있다고 하겠다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11C
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• pp.1077-1084
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• 2006

This paper proposed a fast algorithm to reduce the amount of calculation for inter prediction which takes a great deal of the operational time in H.264/AVC. This algorithm decides a search range according to the direction of predicted motion vector, and then performs an adaptive spiral search for the candidates with JM(Joint Model) FME(Fast Motion Estimation) which employs the rate-distortion optimization(RDO) method. Simultaneously, it decides a threshold cost value for each of the variable block sizes and performs the motion estimation for the variable search ranges with the threshold. These activities reduce the great amount of the complexity in inter prediction encoding. Experimental results by applying the proposed method .to various video sequences showed that the process time was decreased up to 80% comparing to the previous prediction methods. The degradation of video quality was only from 0.05dB to 0.19dB and the compression ratio decreased as small as 0.58% in average. Therefore, we are sure that the proposed method is an efficient method for the fast inter prediction.

• Journal of the Korea Convergence Society
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• v.9 no.5
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• pp.21-26
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• 2018

In this study, HRD-NET (http://hrd.go.kr), a vocational and training integrated computer network operated by the Ministry of Employment and Labor, is used to confirm whether job training information required by job seekers is being provided smoothly The question bulletin board was extracted using 'R' program which is optimized for big data technique. Therefore, the effectiveness, appropriateness, visualization, frequency analysis and association analysis of the vocational training system were conducted through this, The results of the study are as follows. First, the issue of vocational training card, video viewing, certificate issue, registration error, Second, management and processing procedures of learning cards for tomorrow 's learning cards are complicated and difficult. In addition, it was analyzed that the training cost system and the refund structure differentiated according to the training occupation, the process, and the training institution in the course of the training. Based on this paper, we will study not only the training system of the Ministry of Employment and Labor but also the improvement of the various training computer system of the government department through the analysis of big data.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.2
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• pp.78-84
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• 2009

In general video coding systems, motion estimation (ME) is regarded as a vital component in a video coder as it consumes a large amount of computation resources. Fractional pixel motion estimation can improve the video compression rate at the cost of higher computational complexity. It is based on the experimental results that the sum of absolute differences (SAD) shows parabolic shape and thus can be approximated by using interpolation technique. In this paper, we propose a fast fractional pixel search algorithm by combining SASR (Simplified Adaptive Search Range) and the CBCDS (Center Biased Cross-Diamond Search) pattern with the predicted motion vector. Compare with the fractional pel full search and the CBFPS, the proposed CBCDS algorithms can reduce fractional pel search points up to 81.4%, respectively with the PSNR lost about 0.05dB.

• Journal of Information Technology Application
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• v.3 no.4
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• pp.43-62
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• 2001

Time variable has been one of the most important ones to explain consumer behavior. Time-pressure could give some impact on decision making process, consuming process of goods, the frequency of purchasing activities and their behavior about after service. It is widely accepted that on-line shopping through Internet can overcome the time and space limitations consumers usually meet for their shopping activities. If that concept is true, on-line shopping through Internet might be an attractive way for those who feel high time pressure for their shopping activities. To test the impact of time pressure on consumer behavior at Electronic Commerce, this paper set three hypothesis. Questionnaire were distributed to married women around Taejon. Sample size were 73, 39 of which from women who have job, 34 who don't have job. The result of this paper might shed some light on the policy making to develop Internet shopping malls.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.8
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• pp.86-95
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• 1998

Intra-frame video compression, which cannot make use of temporal predictions, requires much higher bit rates compared with inter-frame schemes. In order to reduce bit rates, intra-frame predictive coding methods in DCT domain have been studied especially within the framework of the MPEG-4 video coding standard currently being developed. In this paper, we propose novel intra-frame predictive coding methods in DCT domain with the marginal complexity increase over the conventional methods . The proposed methods consist of a DC coefficient prediction method and two AC coefficient prediction methods. The proposed methods consist of a DC coefficient prediction method and two AC coefficient prediction methods. The proposed DC coefficient prediction method makes it possible to adaptively select the prediction directions without overhead bits, by comparing gradients of DC coefficients from neighboring blocks. As the AC coefficient prediction methods, first, we present an effective method which can improve the prediction directions of the MPEG-4 scheme by considering the DC coefficient of the current block to be coded. And, we present another effective method that decision on the prediction is carried out for each AC coefficient. Simulation results show that substantial bit savings can be achieved by the proposed methods.