• Proceedings of the Korean Society of Computer Information Conference
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• 2021.01a
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• pp.325-326
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• 2021

LNG는 환경규제에 따라 화석에너지에서 친환경 재생에너지로 전환되는데 중요한 역할을 하는 에너지원이다. UN산하 세계해사기구(IMO)의 MARPOL협약에 따라 선박 황산화물 배출가스규제로 LNG추진 선박에 대한 수요가 증가되고 있을 뿐만 아니라 미국의 쉐일혁명으로 LNG를 수출함에 따라 공급의 변화가 급격하게 이뤄지고 있다. 과거 국가 주도의 프로젝트 성격이 강한 LNG 운송시장은 장기정기용선계약이 대부분이었으나 수요와 공급시장의 급격한 변화로 스팟시장의 중요성이 커지고 있다. 따라서 본 논문은 LNG 운송시장에서 시장참여자들의 스팟거래에 합리적인 의사결정이 이뤄지도록 과학적인 예측방법을 제시하고자 한다. LNG 스팟운임 예측에 기계학습모델 중 인공신경망 모델을 적용할 것이며 기존의 시계열분석 방법인 ARIMA모델과 비교하여 본문에서 제시된 모델의 예측성능의 우수성을 확인하였다. 본 논문은 LNG 스팟운임을 다룬 최초의 연구로서 학문적인 차별성이 기대된다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2023.01a
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• pp.289-291
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• 2023

다양한 신재생 에너지 발전 중에서 수력발전은 풍력발전과 더불어 탄소배출이 가장 적은 에너지 발전 중 하나이며, 정부의 "2050 탄소중립" 발표에 따라 근래 수력발전에 대한 관심이 증폭되고 있는 추세이다. 하지만 국내의 지리적 특성상 수력발전의 규모가 국외에 비해 소규모이며, 대규모 수력발전의 경우에도 설치가능지역이 고갈되어 다수의 소규모 수력 발전소 설치라는 방향성이 불가피한 현실이다. 이에 따라 본 연구에서는 유한요소법을 이용하여 소규모 수력발전에 가장 많이 사용되는 콘크리트 댐 형상에 대한 구조해석을 실시하고 정수압 하에서 각 콘크리트 댐의 변형 거동 및 안정성을 분석하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.11a
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• pp.805-807
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• 2007

컴퓨팅 환경이 유비쿼터스 환경으로 변화함에 따라 정보의 량은 증가하지만, 사용자가 이 모든 정보를 수용하기에는 한계가 있다. 그래서 유비쿼터스 환경에서는 장치 스스로 상황을 인지하고 능동적으로 처리할 필요가 있다. 본 논문에서는 블루투스 라디오 신호 세기를 기반하여 위치 인지를 하고 이를 바탕으로 이동중인 사용자에게 동적으로 멀티미디어 스트리밍 스위칭 서비스를 제공하는 u-MESSAGE(ubiquitous MEdia Stream Switcher At Genius home Entertainment) 시스템을 소개한다.

• Journal of the Korea Computer Graphics Society
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• v.17 no.2
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• pp.37-43
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• 2011

OpenVG and SVG Tiny are the most widely used 2D vector graphics technologies for outputs in the various embedded environments including smart phones. Especially, to show high refresh rates on the high resolution screens, it is necessary to effectively accelerate them. Until now, OpenVG and SVG Tiny are available as hardware implementations such as the fully-dedicated graphics chips or full software implementations. Currently available vector graphics silicon chips are relatively expensive and require high power consumption. In contrast, previous full software implementations show lower performance even with almost 100% CPU usages, which would disrupt other multi-threaded applications, In this paper, we present a cost-effective way of accelerating both of OpenVG and SVG Tiny, based on the multimedia-processing hardware, which is wide-spread on the media devices and mobile phones. Through the effective use of these multimedia processors, we successfully accelerated OpenVG and SVG Tiny at least 3.5 times to at most 30 times, even with lower power consumption and lower CPU usage.

• Journal of the Korea Society of Computer and Information
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• v.12 no.4
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• pp.61-68
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• 2007

Two experiments examined the visual memory distortion by presenting 170 subjects with wide-angle views of four scenes on monitor screen. Retention interval of 0, 1 and 48 hours tested in reproduction and recognition experiment. The results of reproduction showed that the subjects tend to magnify the foreground and background of scenes compared to the real input (scene) for all retention intervals. The viewers recognized mure wide-angle views for the same scenes at the retention interval of 1 and 48 hours. These results demonstrated boundary extension is not a robust and unidirectional phenomenon but boundary contraction can be occurred with wide-angle views. The results also suggested that boundary contraction is the product of the activation of a memory schema hypothesis: In memory the representation moves toward a prototypical view and prototypical object size.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.2
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• pp.19-38
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• 2023

Nitrous oxide, one of the six greenhouse gases from Kyoto protocol, is known to be emitted in biological nitrification and denitrification reactions at wastewater treatment plant. In this study, EQPS which is a computer program that can simulate nitrous oxide gas emission amount at wastewater treatment plants is used. The MLE process which treats wastewater from combined sewer is studied. Operational variables which are MLR, water temperature at reactor and primary clarifier by-pass percentage are changed to define the condition which produces the least amount of nitrous oxide gas. 200 % of MLR, 20 ℃ of water temperature at bioreactor and 15 % of primary clarifier by-pass percentage are shown the least nitrous oxide emission factor. Also, it is found that the deep aeration tank produces less amount of nitrous oxide gas since less air is required to meet oxygen demand in this type of aeration tank.

• Journal of the Korean Magnetics Society
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• v.8 no.4
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• pp.231-240
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• 1998

We investigated that the fabrication and reproducing signal characteristics of tri-layered magnetoresistance (MR) element for the high density magnetic thin film heads and sensors. Magnetoresistance curve of tri-layered MR element predicted by computer modeling was saturated above external field of -15 Oe~+22 Oe, and it was shifted to linearized region as large as 4 Oe. In the case of fabricated real device, magnetoresistance curve was saturated above external field of $\pm$15 Oe, and it was shifted to linearized region as large as 4 Oe. As shown in real device, MR response curve was in good agreement with the simulation results. As a result of experimental data of reproducing output signal in real device, it retained normal sinusoidal waveforms in 1~4 Oe external magnetic field. In this magnetic field region, the fabricated heads with tri-layered MR element can be operated with good reproduced characteristics. This will be beneficial to the use of efficient processes of manufacturing elements and the vacuum deposition techniques which control thin film properties.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.12
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• pp.2179-2187
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• 2008

The P2P technology has been widely used to distribute files efficiently, and its use in streaming is rapidly increasing. P2P streaming has issues about startup-delay, scalability, and real-time playback, however, what affects these factors has not been researched sufficiently. This paper suggests a buffering model for progressive download within mesh-based P2P system, which corresponds to downloading and playing the content at the same time. It is used to analyze PDF(Playback Deadline First), Rarest algorithms which are block-selection strategies of P2P streaming and proposes a mixed selection of them. The mixed block selection strategy dynamically performs different strategies based on whether the blocks to be played are received or not. In consequence, it enhances the QoS of streaming in a single peer point of view, as well as improving block distributions in an overlay network.

• Proceedings of The KACE
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• 2018.08a
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• pp.89-91
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• 2018

초 고령사회가 전망됨에 따라 적극적인 문화향유를 즐기는 다양한 신체적 활동성이 있는 새로운 실버세대를 스마트 시니어라고 지칭한다. 이전 연구에서는 스마트 시니어의 신체적 노화나 운동능력 저하를 고려하여 제공하는 맞춤형 UI/UX 콘텐츠 서비스를 제공하였다. 또한 스마트 시니어의 인지 반응 검사를 통하여 인지적 특성 저하 요소를 파악하고 A, B, C 그룹으로 나뉘어 그룹 특성에 맞게 글자 크기, 폰트 종류, 재생 속도 등 설정을 조정하여 맞춤형 UI/UX 콘텐츠를 제공하였다. 그러나 약 180여개의 인지 반응 검사를 진행함에 따라 스마트 시니어의 집중력 저하의 문제점이 있었다. 본 논문에서는 스마트 시니어의 인지 반응 검사지와 온라인 콘텐츠에서 스마트 시니어가 활동하여 변경된 설정 값을 이용하여 유의미한 인지반응 검사지를 추출하고 인지 반응 검사지 결과를 통해 상세한 맞춤형 UI/UX 콘텐츠를 제공하는 모델을 제안한다.

• Journal of the Korea Computer Industry Society
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• v.7 no.3
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• pp.217-226
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• 2006

Intensive studies have been made in the area of N-VOD server Multimedia files in the N-VOD sever are characterized with the large volume of data, the requirements of synchronization and real-time playback of streams. The basic goal of the study is to find an efficient mechanism to allow maximum number of users under the limited resources such as Buffer size and disk bandwidth. we propose a efficient VCR-LIKE operations and buffer, disk scheduling policy for multimedia services with management of VOD sever resources. Simulation results show that the rate of buffer usage and service time of proposed scheme are about 18% performance improved than that of traditional methods. This implies that our method can allow much more users for given resources.