• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.5
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• pp.1200-1210
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• 1990

Conventional efficiencies of the adiabatic compression process such as isentropic efficiency and polytropic efficiency can be explained as exergetic efficiencies replacing the reference atmospheric temperature with the temperature which can be determined in the process itself. So that, other efficies such as maximum isentropic efficiency can be defined by giving proper reference temperatures. By applying the same logical principles, exergetic and other rational efficiencies for the non-adiabatic compression process are also defined and discussed for their physical meanings and reasonable engineering applications.

• Resources Recycling
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• v.27 no.2
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• pp.63-67
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• 2018

Gibbs free energy is a measure of relative stability among substances. Since the nature of the ions in aqueous solution is diverse, their thermodynamic data at extensive experimental conditions is scarce. In this work, the calculation procedure was introduced to obtain the absolute and conventional standard molar enthalpies and entropies of hydration of ions from the standard enthalpies and entropies of formation of hydrated ions. The application of correspondence principle to estimate thermodynamic data at high temperature was explained.

• Bioinformatics and Biosystems
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• v.1 no.2
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• pp.103-108
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• 2006

Computational prediction of protein-ligand binding has been widely used as a tool to discover lead compounds fur new drugs. Prediction accuracy is determined in part by the scoring function used in docking calculations. Diverse scoring functions are available, and these can be classified into force-field based, empirical, and knowledge-based functions depending upon the basic assumptions made in development. Among these, force-field based functions consider physical interactions the most in detail. However, the force-field based functions have the drawback of not including the entropic effect while considering only the energy contribution such as dispersion or electrostatic forces. In this article, a method to take into account of the entropic effect using the colony energy is suggested when force-field based scoring functions is used by extracting conformational information obtained from the pre-existing docking program. An improved result for decoy discrimination is illustrated when the method is applied to the DOCK scoring function, and this implies that more accurate docking calculation is possible.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.2
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• pp.206-212
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• 2006

Many image and video compression algorithms work by splitting the input image into blocks and producing variable-length coded bits for each block data. If variable-length coded data are transmitted consecutively, then the resulting coder is highly sensitive to channel errors. Therefore, most image and video techniques for providing some protection to the stream against channel errors usually involve adding a controlled amount of redundancy back into the stream. Such redundancy might take the form of resynchronization markers, which enable the decoder to restart the decoding process from the known state, in the event of transmission errors. The Error Resilient Entropy Code (EREC) is a well known method which can regain synchronization without any redundant information to convert from variable-length code to fixed-length code. This paper proposes an enhancement to EREC, which greatly improves its transmission ability for the compressed image quality without any redundant bits in the event of errors. The simulation result shows that the both objective and subjective quality of transmitted image is enhanced compared with the existing EREC at the same BER(Bit Error Rate).

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.287-290
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• 2011

분산 동영상 부호화 시스템에서는 복호기에서 움직임 보상 보간 기법을 이용하여 부가정보를 생성한다. 생성된 부가정보와 원 Wyner-Ziv 프레임간의 차이를 채널 부호로 오류 정정하게 되는데 이때 부호기에서는 복호기에서의 오류 정정을 위하여 패리티 비트인 Wyner-Ziv 비트를 복호기로 보내게 되고 복호기에서는 이 Wyner-Ziv 비트를 이용하여 Wyner-Ziv 프레임을 복원하는데 더 많은 Wyner-Ziv 비트가 필요할 경우 피드백 채널을 통해 Wyner-Ziv 비트를 요청하게 된다. 이때 부호기에서 조건부 엔트로피를 구할 수 있다면 이를 이용하여 Wyner-Ziv 비트 전송량을 제어함으로써 피드백 채널을 제거 할 수 있다. 이를 위해 부호기에서도 부가정보를 알아야하는데 복호기에서 사용하는 부가정보 생성 기법은 복잡도가 높기 때문에 사용할 수 없다. 본 논문에서는 부호기에서 간단한 부가정보를 생성하는 방법을 제안하고 분산 동영상 부호화 시스템에 적용하여 피드백 채널을 제거하였을 때의 성능을 분석하였다.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2002.11a
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• pp.328-335
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• 2002

최근 들어 인터넷 기술의 발달로 웹 상에 많은 자료들이 산재해 있습니다. 사용자가 원하는 정보를 검색하기 위해서 키워드 검색을 이용하고 있는데 이러한 키워드 검색은 사용자들이 입력한 단편적인 정보에 바탕하여 검색하고 검색된 결과들을 자체적인 기준으로 순위를 매겨 나열식으로 제시하고 있다. 이러한 경우 사용자들의 생각과는 다르게 결과가 제시될 수 있다. 따라서 사용자들의 검색 시간을 줄이고 편리하게 검색하기 위한 환경의 필요성이 높아지고 있다. 본 논문에서는 Suffix Tree 알고리즘을 사용하여 관련있는 문서들을 분류하고 각각의 분류된 클러스터에 제목을 생성하기 위하여 문서 빈도수, 단어 빈도수와 역문서 빈도수, 카이 검정, 공통 정보, 엔트로피 방법을 비교 평가하여 제목을 생성하는데 어떠한 방법이 가장 효과적인지 알아보기 위해 비교 평가해본 결과 문서빈도수가 TF-IDF보다 약 10%정도 성능이 좋은 결과를 보여주었다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.140-142
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• 2021

Mobile communication technology after 5th generation requires high speed, hyper-connection, and low latency communication. In order to meet technical requirements for secure hyper-connectivity, low-spec IoT devices that are considered the end of IoT services must also be able to provide the same level of security as high-spec servers. For the purpose of performing these security functions, it is required for cryptographic keys to have the necessary degree of stability in cryptographic algorithms. Cryptographic keys are usually generated from cryptographic random number generators. At this time, good noise sources are needed to generate random numbers, and hardware random number generators such as TRNG are used because it is difficult for the low-spec device environment to obtain sufficient noise sources. In this paper we used the chip which is based on quantum characteristics where the decay of radioactive isotopes is unpredictable, and we presented a variety of methods (TRNG) obtaining an entropy source in the form of binary-bit series. In addition, we conducted the NIST SP 800-90B test for the entropy of output values generated by each TRNG to compare the amount of entropy with each method.

• Journal of The Korean Association of Information Education
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• v.19 no.1
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• pp.139-148
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• 2015

The purpose of image fusion is to combine the relevant information from a set of images into a single image, where the resultant fused image will be more informative and complete than any of the input images. Image fusion techniques can improve the quality and increase the application of these data important applications of the fusion of images include medical imaging, remote sensing, and robotics. In this paper, we suggest a new method to generate a fusion image using the close relation of image features obtained through maximum entropy threshold and mutual information. This method represents a good image registration in case of using a blurring image than other image fusion methods.

• Annual Conference on Human and Language Technology
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• 2018.10a
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• pp.522-526
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• 2018

본 연구는 수많은 챗봇이 생성될 수 있는 챗봇 빌더 시스템에서 저비용 컴퓨팅 파워에서도 구동 가능한 가벼운 문장 분류 시스템을 제안하며, 미등록어 처리를 위해 워드 임베딩 기법인 GloVe를 이용하여 문장 벡터를 생성하고 이를 추가 자질로 사용하는 방법을 소개한다. 제안한 방법으로 자체 구축한 테스트 말뭉치를 이용하여 성능을 평가해본 결과 최대 93.06% 성능을 보였으며, 자체 보유한 CNN 모델과의 비교 평가 결과 성능은 2.5% 낮지만, 모델 학습 속도는 25배, 학습 시 메모리 사용량은 6배, 생성된 모델 파일 크기는 302배나 효율성 있음을 보였다.

• The KIPS Transactions:PartB
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• v.11B no.4
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• pp.477-484
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• 2004

The technique of sequential pattern mining means generating a set of inter-transaction patterns residing in time-dependent data. This paper proposes a new method for generating sequential patterns with the use of Hellinger measure. While the current methods are generating single dimensional sequential patterns within a single attribute, the proposed method is able to detect multi-dimensional patterns among different attributes. A number of heuristics, based on the characteristics of Hellinger measure, are proposed to reduce the computational complexity of the sequential pattern systems. Some experimental results are presented.