• Journal of Korea Multimedia Society
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• v.7 no.11
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• pp.1521-1530
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• 2004

In this paper, we present effective quantization noise reduction algorithm using signal adaptive filter and linear combination between blocks in multimedia system. In the proposed method, all of the blocks are classified into low frequency blocks, high frequency blocks, and midrange blocks according to DCT coefficients. Ringing artifacts are shown in high frequency blocks. So ringing artifact reduction algorithm is performed in high frequency blocks using a signal adaptive filter. And the blocking artifact reduction is performed by replacing the pixel value of blocky blocks using linear combination between blocky block and remote unblocky block. The simulation results shows better performance in respective of the subjective and objective image quality than the conventional method.

• Journal of Advanced Navigation Technology
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• v.18 no.4
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• pp.312-318
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• 2014

The altitudes of GEO satellites are higher than those of GPS satellites. Therefore the visibility and the received power of GPS signals are totally different from those of the users near the Earth's surface. In this study, we analyzed the visibility of GPS signals received on GEO satellites. And we also developed a software GPS receiver that works on GEO satellites using CCMDB algorithm which is a weak signal receiver algorithm. GPS signals received on a GEO satellite are generated by a commercial hardware GPS simulator and used for the verification of the developed software GPS receiver. The mean 3D position and velocity error are calculated as 165.636 m and 0.5081 m/s.

• Journal of Korean Society of Forest Science
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• v.94 no.4 s.161
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• pp.277-280
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• 2005

In order to prevent chestnuts from damage by the peach pyralid moth, Dichocrosis punctiferalis, a sprinkler system was installed on the chestnut orchard. Such a test was conducted at Yeoju-gun, Gyeonggi-do, Korea in 2002. Insecticides of fenitrothion 50% EC, x1,000 and diflubenzuron 25% Wp, x2,500 were sprayed at ten-day fifteen-day and twenty-day intervals during the period of D. punctiferalis adult occurrence by sprinkler system. The peach pyralid moths generally emerged for about 60 days from early July to early September, and peak emergence was 10 days from late July to early August. Damage rate of chestnuts were 0.9-4.0% on average with this crown insecticide spraying with diflubenzuron, while 30.4% when not treated. Control effectiveness of this insecticide spraying was 92%(86.7-97.0%). In conclusion, effectual times and number of insecticide application with sprinkle system against peach pyralid moth were from early July to late August and four or five times at ten or fifteen day intervals, respectively.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.4
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• pp.685-692
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• 1995

The effect of five different surface treatments on the shear bond strength of the resin bond to Type IV Gold alloy was studied by bonding resin to metal. The metal surface was subjected to one of the following treatments and bonded ;(1) air abraded with $50{\mu}m$ alumina particles,(2) beads(3) beads and tin-plated at curreant density of 300mA/$cm^2$,(4) tin-plated at current density of 300mA/$cm^2$,(5) silicacoating with sililink, and bonded with an MDP Opaque primer, CESEAD resin system. The bonded specimens were immersed in water for 23 hours after 1 hour resin curing and shear bond strength were recorded. On the basis of this study, the following conclusions can be drawn; 1. Difference were found in the shear bond strength among all experimental groups. And bead glroup exihibited the highest shear bond strength and sand blasting group exhibited the lowest shear bond strength on five groups. 2. Bead group, mechanical bonding was significantly higher than that obtained with the samples, tinplating, silicacoating, and chemical bonding. 3. No statistically signiflcant difference was found between the shear bond strengths obtained with bead and bead-tinplating, and between tinplating and sili cacoating.

• Journal of Korea Multimedia Society
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• v.11 no.1
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• pp.13-22
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• 2008

This paper proposes an efficient ROI code block discrimination algorithm for dynamic ROI coding. The proposed algorithm calculates the girth of the ROI only with some mask information in consideration of the characteristics of the shape of the ROI for reducing a ROI code block discrimination time, and this proposed algorithm discriminates whether there is a ROI code block by the girth and the critical value of the ROI. Also, this discrimination algorithm is capable of treating the coefficients of the background within a ROI code block preferentially and controlling a loss by controlling the threshold value of the ROI. In order to demonstrate the utility of the proposed method, this paper conducted a comparative experiment of the proposed method with the existing methods. As a result of this experiment, it was confirmed that the proposed method was superior to the conventional methods in terms of quality and speed.

• Journal of Korea Multimedia Society
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• v.14 no.8
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• pp.981-991
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• 2011

MIP(Maximum Intensity Projection) is a volume rendering technique which is essential for the medical imaging system. MIP rendering based on the ray casting method produces high quality images but takes a long time. Our aim is improvement of the rendering speed using GPGPU(General-purpose computing on Graphic Process Unit) technique. In this paper, we present the ray casting algorithm based on CUDA(an acronym for Compute Unified Device Architecture) which is a programming language for GPGPU and we suggest new acceleration methods for CUDA. In detail, we propose the block based space leaping which skips unnecessary regions of volume data for CUDA, the bisection method which is a fast method to find a block edge, and the initial value estimation method which improves the probability of space leaping. Due to the proposed methods, we noticeably improve the rendering speed without image quality degradation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.5
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• pp.1002-1011
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• 2005

In this paper. we design and implement a bi-directional broadcasting system, so called return channel server, to allow users to participate in a broadcasting program by using a hi-directional interaction channel. To provide user participation in a program and reflect the user's opinions or responses in real time, the return channel server can be viewed as consisting of four major functional modules: a control module, network interface module, DBMS module, and real-time content authoring module. To construct a return channel server that has a service independent architecture, we designed a return channel server to include the hierarchical structure. The presented return channel server consists of two parts: an RCSAE(return channel server application environment) and RCSA(return channel server application). An RCSA is composed of an execution code and a parameter for executing the execution code. RCSA defines the procedures for providing a specific broadcasting program using the return channel server. On the other hand, an RCSAE provides the environment for the execution of RCSAS. By adopting RCSAE and RCSA, we construct the return channel server that has a service-independent architecture which are shown by the test.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.901-904
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• 2007

Nowadays, in many fields of medical treatment, we can make an observation and a diagnosis of inward disease without using a surgical operation. As one of them, ultra-sound diagnosis system can be available widely in its cost and size compared with other medical instruments. This system also make it possible for us to see the inner parts of the body in real time harmlessly for a long time. So it can be utilized to inspect the movement of heart or fetus and to diagnose an internal disease of the soft tissues. Ultra-sound images can be generated by the reflexive and scattered wave through the pulse generator and so in ultrasound images there exist inherently many affective noised signals. In this paper, we are to take an noise-restrained image and to extract a more affective regions of the images.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1998.05a
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• pp.39-44
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• 1998

현재 국내에 보급되어 있는 현대화 온실 203개를 대상으로 냉난방과 관련된 설비현황을 조사하여 분석한 결과를 요약하면 다음과 같다. \circled1 온실의 건설방위는 남북동(58.1%)과 동서동(26.8%)이 대부분이었고, 철골온실은 Wide-span형이 81.8%, 플라스틱온실은 1-2W형 온실이 97.5%였다. 휴작하는 온실은 약 41%정도였고, 재배작물은 채소류가 약 80%, 화훼류가 약 20%정도였으며, 재배방식은 철골온실의 경우 양액재배가 57.2%, 플라스틱온실에서는 토양재배가 88.5%였다. \circled2 온실의 외부 피복재는 철골온실은 유리가 92.2%, 플라스틱온실에서는 PE가 43.3%, EVA가 51.9%로 대부분이었다. 철골온실은 1중피복이 98.7%로 거의 전부이었고, 플라스틱온실에서는 2중피복이 78.7%로 나타나, 철골온실에서 보온커튼을 통한 보온성 향상과 밀폐성이 더욱 중요함을 알 수 있다. \circled3 보온용 피복재는 부직포가 64.9%로 가장 많았고 대부분 2층커튼(85.9%)이었으며, 개폐방식은 대부분 예인식(92.7%)의 자동개폐방식(75.2%)이었다. 한편 바닥을 피복한 온실은 약 30% 정도로 나타나, 바닥피복으로 인한 축열이나 반사효과를 감안할 때 효율적인 바닥처리가 요망된다. \circled4 온실의 난방방식은 철골온실에서는 온수안방(47.3%)이 온풍난방(33.8%)보다 다소 많았으며, 플라스틱온실에서는 대부분 온풍난방(90.8%)이었다. 온실의 난방위치는 대부분 지상난방(89.8%)이었고 지중난방은 극소수로 나타나, 앞으로 지중난방을 통한 난방비 절감과 품질향상에 관한 실용화 연구가 요망된다. 난방용 연료는 대부분 경유(83.9%)로 나타나, 난방비를 절감할 수 있는 저가의 연료를 사용할 수 있는 난방시스템의 개발이 요청된다. \circled5 온실의 냉방방법은 차광(51.8%)과 지붕살수(33.9%)가 대부분이었으며 미스트와 포그시스템을 설치한 온실은 소수에 불과하였고, 극소수의 온실에서는 지붕위나 온실내에 지붕면과 평행하게 설치한 경우도 있었다.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.372-376
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• 2011

본 연구는 설마천 시험유역(경기도 파주시 적성면 소재)을 운영하면서 수문현상을 관측하여 신뢰성 있는 수문자료를 지속적으로 획득하고 물순환 과정을 규명하는데 있다. 이를 위하여 2010년에도 지속적인 수문관측 및 측정을 하였으며, 수문자료의 품질 향상을 위한 관측기기의 유지관리와 수집된 자료의 처리절차를 통하여 신뢰성 있는 수문자료를 생성하고, 이들 자료를 바탕으로 유역의 수문특성을 분석하였다. 시험유역에서 생성되는 자료에는 6개 우량관측소의 우량자료, 2개 수위관측소의 하천수위 및 지하수위, 유량측정성과, 수질 자료, 1개 하천수위관측소의 부유사량 자료, 1개 기상관측소의 기상자료 등이 있으며, 이로부터 산정된 유역평균우량과 유량자료 등이 있다. 실시간 전송장비와 설마천 시험유역 홈페이지(http://seolmacheon.kict.re.kr)로 구성된 수문정보시스템을 통해 관측자료와 가공자료를 등록하였으며, 실시간 전송자료 제공은 물론 확정된 자료를 신청절차를 통해 일반에게 제공하고 있다. 확정된 강우-유출 자료를 이용하여 강우의 호우사상 분석(강우강도, 지속기간), 강우의 지속기간별 최대강우량, 각 지점간 강우량 비교, 강우의 시 공간분포 특성 분석, 월별 유출 및 주요 호우사상의 유출특성 분석 등 기본적인 강우-유출 특성을 분석하였다. 그리고, 유량측정성과의 불확실도 분석을 통하여 측정한 유량자료의 정확도 제고와 현장의 유량자료의 정확도를 개선하기 위하여 유량정보시스템(Parshall Flume, Argonaut-SW, Cableway System에 의한 유량정보 생성)을 운영 평가하였다. 또한, 수질, 부유사량의 특성 분석은 본 유역의 물질순환 해석을 위한 기초자료로 충분히 활용될 수 있다. 관측자료를 이용하여 유역의 유입량과 유출량에 대한 물수지 분석을 하였으며, 각 요소별 정량적인 값을 도출함으로써 물순환 과정을 해석 할 수 있는 기반을 구축하였다. 설마천 시험유역에서 축적된 수문자료는 자료의 공유를 통하여 자료의 검증을 확보함과 동시에 시험유역의 연구성과가 수자원 개발 분야에 활용되기 위해서는 지속적이고 안정적인 자료확보와 수문관측 기술개발을 위한 기반구축이 더욱더 필요한 상황이다.