• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2010년도 춘계학술발표논문집 2부
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• pp.961-964
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• 2010

A semi-empirical fluctuation term is presented to improve a classical equation of state (EOS) for volumetric properties in the critical region. The term is based on the two assumptions: (1) The Helmholtz energy is individually divided into classical and long-range density fluctuation contribution (2) All molecules form cluster near the critical region due to long-range density fluctuation. To formulate such molecular cluster, we extended the Veytsman statistics originally developed for the cluster due to hydrogen bonding. The probability function in the statistics is modified to represent the characteristics of long-range density fluctuation vanishing far from critical region. The proposed fluctuation contribution was incorporated into the Sanchez-Lacombe EOS and the combined model with 6 adjustable parameters has been tested against experimental VLE data. The combined model is found to well represent flatten critical isotherm for methane and top of the coexistence curve for the tested components. The prediction results for caloric data are in good agreement with the experimental data.

• 한국인터넷방송통신학회논문지
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• 제24권3호
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• pp.95-101
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• 2024

주어진 숫자 쌍 간에 빈 셀을 경유하는 선을 연결함에 있어 다른 숫자의 연결선과 교차가 발생하지 않도록 하는 숫자 연결 퍼즐은 다항시간으로 퍼즐을 풀 수 있는 방법이 알려져 있지 않은 NP-완전 문제이다. 지금까지는 임의의 숫자를 선정하여 시행착오 법으로 퍼즐을 풀고 있다. 본 논문은 주어진 문제에 대해 빈 셀을 정점으로, 인접 셀들 간에 간선으로 연결한 격자 그래프로 변환하였다. 다음으로 숫자 쌍 들 간에 직선을 긋고, 교차가 발생한 숫자 그룹으로 분할하였다. 교차 숫자 그룹에서 교차를 회피하는 우회 경로를 설정하였다. 제안된 알고리즘을 18개의 벤치마킹 데이터들에 적용한 결과 모든 데이터에 대해 퍼즐을 O(n)의 선형시간 복잡도로 풀 수 있음을 보였다.

• 광물과 암석
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• 제33권3호
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• pp.259-272
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• 2020

지각내부에서의 지진파 전파 특성은 지각의 주요 구성광물들의 격자선호방향에 크게 영향을 받는다. 따라서 지진파 전파속도자료를 이용해 지구내부구조를 해석하기 위해서는 해당 지역의 주요 구성 광물들의 격자선호방향과 이를 이용해 계산된 암석별 지진파 전파속도 특성 자료가 필요하다. 하지만 국내의 암석과 광물의 격자선호방향에 대한 연구는 거의 없는 상황이다. 이번 연구에서는 경기육괴 북부에 위치한 가평 위곡리 일대의 두 각섬암체에서 각섬암을 채취하여, 각섬암 내부의 주요 광물들, 특히 각섬석과 사장석의 격자선호방향을 전자현미경/후방산란전자회절 기기를 통해 분석하고, 이를 이용해 가평지역 각섬암에서 나타나는 지진파 전파속도 특성을 계산하였다. 분석결과 가평 위곡리 일대 두 개의 각섬암체에서 각각 type I과 type IV로 정의된 두 가지 타입의 각섬석 격자선호방향이 관찰되었다. 사장석은 비교적 약한 격자선호방향을 보여주었다. Type I 각섬석 격자선호방향이 관찰된 각섬암에서는 큰 지진파 비등방성이 관찰되었으나, type IV 각섬석 격자선호방향이 관찰된 각섬암에서는 작은 지진파 비등방성이 관찰되었다. 이것은 이전의 실험결과와 일치하는 결과이다. 빠른 S파의 편파방향은 각섬석의 격자선호방향에 관계없이 선구조방향에 평행하게 나타났다. 가평지역의 각섬암에서 관찰된 이러한 지진파 전파 특성은 경기육괴 지각 내부의 구조와 지진파 자료를 해석하는데 도움을 줄 수 있을 것으로 기대된다.

• 전자통신동향분석
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• 제36권6호
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• pp.1-12
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• 2021

As the demand for big data and big data-based artificial intelligence (AI) technology increases, the need for privacy preservations for sensitive information contained in big data and for high-speed encryption-based AI computation systems also increases. Fully homomorphic encryption (FHE) is a representative encryption technology that preserves the privacy of sensitive data. Therefore, FHE technology is being actively investigated primarily because, with FHE, decryption of the encrypted data is not required in the entire data flow. Data can be stored, transmitted, combined, and processed in an encrypted state. Moreover, FHE is based on an NP-hard problem (Lattice problem) that cannot be broken, even by a quantum computer, because of its high computational complexity and difficulty. FHE boasts a high-security level and therefore is receiving considerable attention as next-generation encryption technology. However, despite being able to process computations on encrypted data, the slow computation speed due to the high computational complexity of FHE technology is an obstacle to practical use. To address this problem, hardware technology that accelerates FHE operations is receiving extensive research attention. This article examines research trends associated with developments in hardware technology focused on accelerating the operations of representative FHE schemes. In addition, the detailed structures of hardware that accelerate the FHE operation are described.

• 응용통계연구
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• 제24권6호
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• pp.1225-1235
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• 2011

본 논문은 수치기상모형에 의해 계산된 수치기상모의풍속($1km{\times}1km$ 해상도)의 정확도를 향상시키기 위한 통계적 보정법을 제안하였다. 이를 위해 남한전역을 $1km{\times}1km$ 격자로 나눈 지점(345,682지점)에 적합한 통계적 바람장 모형으로 부터 남한지역의 바람장을 추정하는 절차와 격자지점별/월별 보정인자를 계산하여 추정된 바람장과 수치 기상모의풍속간의 간극을 보정하는 절차로 이루어진 보정인자법을 개발하였다. 또한 75개 기상관측소지점에서 계산된 수치기상모의풍속자료에 보정인자법을 적용시켜 본 논문에서 제안된 보정법의 유용성을 보였다.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1997년도 Proceedings of the 12th KACG Technical Meeting and the 4th Korea-Japan EMGS (Electronic Materials Growth Symposium)
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• pp.149-155
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• 1997

We have successfully grown colorless and transparent Rb-doped potassium niobate (KRN) single crystals using the top seeded solution growth(TSSG) technique. In our crystal growth experiments, the Rb doping concentrations within the melt range from 2-15 mol% relative to that of Nb$_2$O5. Atomic absorption measurements indicate that the Rb content in the KRN solid solution is rather low; the Rb segregation coefficient is found to be on the order of 0.05. It is believed that this is due to the relatively much larger Rb+ ionic radius compared to that of K+, rendering it more difficult for Rb to replace K in the KNbO$_3$(KN) host lattice. Preliminary single-pass second harmonic generation (SHG) experimental results indicate that there exists marginal improvement in the phase-matching temperature tolerance of KRN compared to that of pure Kn single crystals.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1549-1552
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• 1997

In this paper, a optimal algorithm that can produce the FOV is proposed in terms of using the Kohonen's Self-Organizing Map(KSOM). A FOV, that stands for "Field Of View", means maximum area where a camera could be wholly seen and influences the total time of inspection of vision system. Therefore, we draw algorithm with a KSOM which aims to map an input space of N-dimensions into a one-or two-dimensional lattice of output layer neurons in order to optimize the number and location of FOV, instead of former sequentila method. Then, we show demonstratin through computer simulation using the real PCB data. PCB data.

• 전자공학회논문지B
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• 제33B권5호
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• pp.109-178
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• 1996

For each reference station and user, the proposed DGPS system is implemented by a GPS module and a modem. The reference station makes plans of the receiving schedule from the satellite sets at each period and then provides the correction data for various satellite sets in a period. Users can utilize the correction data continuously and efficiently through the recursive least squares lattice filters. Furthermore, after taking DGPS techniques, we can improve the positioning accuracy using a kalman filter by decreasing anti-common errors between a reference station and a user. Experimental results show the positioning accuracy of better than 5 meters in almost real time.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.580-583
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• 1992

In calculating the hysteresis loops with the Preisach model for ferromagnetism, Everett function is used generally. Because the Everett function is usually given as a table of the lattice-shaped, it is very difficult to directly obtain the Everest table from the data. Therefore this makes some defects in the calculation processes or the accuracy of the results. In this study, using the data sufficiently obtained from the experiment by drawing up the Everett table in the triangle-shaped, and applying the generalized hysteresis model in which the magnetization is depend on the sum of the applied magnetic field and the molecular field, it is shown that our proposal is acceptible in calculating the hysteresis processes.

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권5호
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• pp.414-418
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• 2004

A 'minimally complex problem set' for ab initio protein Structure prediction has been proposed. As well as consisting of non-redundant and crystallographically determined high-resolution protein structures, without disulphide bonds, modified residues, unusual connectivities and heteromolecules, it is more importantly a collection of protein structures. with a high probability of being the same in the crystal form as in solution. To our knowledge, this is the first attempt at this kind of dataset. Considering the lattice constraint in crystals, and the possible flexibility in solution of crystallographically determined protein structures, our dataset is thought to be the safest starting points for an ab initio protein structure prediction study.