• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.3
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• pp.77-85
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• 2002

A Research of binary random sequence generator that uses a linear shift register had been studied since the 1970s. These generators were used in stream cipher. In general, the binary random sequence generator consists of linear shift registers that generate sequences of maximum period and a nonlinear filter function or a nonlinear combination function to generate a sequence of high linear complexity. Therefore, To generate a sequence that have long period as well as high linear complexity becomes an important factor to estimate safety of stream cipher. Usually, the maximum period of the sequence generated by a linear feedback shift register with L resistors is less than or equal to $2^L$-1. In this paper, we propose new binary random sequence generator that consist of L registers and 2 sub-characteristic polynomials. According to an initial state vector, the least period of the sequence generated by the proposed generator is equal to or ions than it of the sequence created by the general linear feedback shift register, and its linear complexity is increased too.

• Journal of the Korean Society for Railway
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• v.16 no.2
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• pp.99-103
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• 2013

In this paper, research on the thermal analysis method is reported for the characterization of heat generation while operating an Interior Permanent Magnet Synchronous Motor (IPMSM) for railway vehicles. Efficient cooling of the heat generated in the IPMSM is important because the excessive heat generated from the winding, core and permanent magnets increases the difficulty of continuously operating an IPMSM over long time periods. Therefore, in this study, in order to analyze the heat generation characteristics of the IPMSM for advanced research in the application of IPMSMs to cooling devices, the heat transfer coefficients for each component of the IPMSM were derived and the thermal equivalent circuit was configured to perform thermal analyses. Finally, the validation of the suggested thermal analysis method was performed through comparison with the heat experimental data of an IPMSM prototype.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.213-213
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• 2022

본 논문은 슬로싱(Sloshing) 거동에 놓인 극저온 액체수소 화물창의 BOG 예측을 위한 CFD 해석 절차를 다루고 있다. 특히, 적재율(Filling Ratio)에 따라 달라지는 열 유입과 그에 따른 액체수소의 기화 경향을 파악하기 위한 목적으로 수행되었다. 액체수소와 기체수소의 혼재에 의한 다상 열유동(Multiphase-Thermal flow) 특성을 반영하고 유동에 따른 강제 대류 현상을 열유속에 반영하기 위한 CFD 해석을 수행하였다. 다상 유동 모델의 정확성을 검증하기 위하여 슬로싱 실험의 압력 계측 값과 해석의 압력 값 및 자유수면(Free surface) 형상을 비교하였다. 소형 C-Type 독립형 액화수소 탱크를 대상으로 슬로싱 유동과 BOG 발생을 수치적으로 예측하였다. 해석 과정에서 VOF(Volume of fraction) 모델과 Eulerian 모델을 모두 적용하여, 액체수소에 유입되는 열 유속(Heat flux)의 예측 정확성을 비교하였다. 슬로싱 유무에 따라 액체수소에 유입되는 열 유속을 비교하여 슬로싱 유동의 포함 여부에 따른 BOG 발생량의 변화를 제시하였으며, 최종적으로 액체수소의 충전율(Filling ratio) 별로 BOG 발생량의 경향성을 제시하였다.

• Horticultural Science & Technology
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• v.33 no.4
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• pp.479-485
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• 2015

This study was conducted to study the factors inducing micro-cracking and determine proper practices to reduce its occurrence in 'Mansoo' pear fruits. Micro-cracking was observed on ripe fruits. Occurrence of micro-cracking was closely related to sun duration time in August. Micro-cracking occurred severely with shorter sun duration, but weakly with longer sun duration and continuous sunlight. Micro-cracking fruits occurred more frequently in trees with a pergola training system than in those with Y-trellis, but there was no difference between the irrigated and non-irrigated groups. While no micro-cracking was observed without fruit bagging, micro-cracking occurred in fruits with black and yellow outer paper bagging at rates of 62.2 and 17.3%, respectively. Our results suggest that the light condition was the most important cause of micro-cracking because the occurrence of micro-cracking in 'Mansoo' fruits was affected by factors including sun duration, trellis system and fruit bag color. We suggested that micro-cracking could be reduced in 'Mansoo' fruit by optimizing the light conditions with the proper trellis system, bagging color and summer pruning.

• Magazine of the Korea Concrete Institute
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• v.14 no.6
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• pp.82-87
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• 2002

매스 콘크리트 구조물에서는 콘크리트의 타설후 시멘트의 수화반응에 의해 발생하는 수화열로 인하여 적지 않은 크기의 인장응력이 유발되어 균열이 발생할 가능성이 크다. 토목분야에서 통용되고 있는 많은 범용구조해석 프로그램들은 유한요소법을 이용하여 수화열에 의한 온도분포해석 및 열응력해석을 수행할 수 있는 기능을 내장하고 있다. 그러나, 다른 모든 구조해석들이 그러하듯이 수화열 해석 역시 해석자가 적절한 입력자료를 프로그램에 제공하지 않았을 경우 예상과는 다른 결과를 산출할 수 있다.(중략)

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2013.11a
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• pp.219-220
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• 2013

본 연구에서는 최근 5년간 서울 지역에서 발생한 월별 화재 건수와 동일한 지역에서 같은 기간 동안 가정용으로 사용된 전기량 사이에 존재하는 연관성을 파악하기 위하여, 이 두 변수에 대하여 시계열분석을 수행하였다. 본 연구에서는 통계전용 인터프리터 언어 R이 사용되었으며, 특히 칼만 필터를 이용한 데이터 처리를 위해 R에서 제공되는 KFAS(Kalman Filtering And Smoothing) 패키지가 사용되었다. 우선 시계열분석을 통해 월별 화재발생 건수는 1년을 주기로 하는 사인파 곡선의 형태로 변화하지만, 가정용 전기사용량은 1년에 두 번씩, 즉 여름철과 겨울철에 크게 증가한다는 사실을 확인할 수 있었다. 더 나아가 KFAS의 파라미터를 적절히 조절함으로써, 가정용 전기사용량과 월별 화재발생 건수 사이의 연관성을 가시적으로 보여줄 수 있었다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.3
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• pp.1147-1152
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• 2012

In this paper, it is key issue about analysis of characteristics processing of digital random output stream of hardware random number generator, which is applied in medical area. The output stream of random number generator based on hardware binary random number is effected from factors such as delay, jitter, temperature, and so on. In this paper, it presents about major factor, which effects hardware output random number stream, and the randomness of output stream data, which are combined output stream and postprocessing data such as encryption algorithm, encoding algorithm, is analyzed. the analyzed results are evaluated by major test items of randomness.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.1980-1982
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• 2005

Power MOSFET의 구동시에는 많은 열이 발생하게 된다. 이때 발생하는 열은 소자의 특성이나 수명에 영향을 주어 오동작을 하게되는 원인이 되기도 한다. 일반적으로 열이 많이 발생하는 chip이나 개별소자의 경우 히트싱크를 부착하여 사용하게 된다. 본 논문에서는 열을 방출시키기 위해 사용되는 히트싱크에 의한 열 전달(Thermal Transient) 특성의 변화 및 히트싱크의 부착에 이용되는 히트싱크 컴파운드(heat sink compound)에 의한 열 전달 특성에 미치는 영향 등을 실험을 통하여 분석하였고, 이를 기술하였다.

• Electric Engineers Magazine
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• v.230 no.10
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• pp.30-33
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• 2001

음향공명 발생원인 가스가 들어있는 방전관내에 방전전류가 흐르면 전력에너지가 발생하여 열을 발생 시키고 이 열은 방전관내의 압력변화를 가져온다. 이 압력변화는 방전관내의 음향변화와 같다. 주기적인 압력변화가 내벽에 반사되어 정재파가 발생되는 현상이 방정관의 고유진동수이며 이 고유진동수와 전원주파수가 일치될 때 음향공명현상이 일어난다.

• Geophysics and Geophysical Exploration
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• v.23 no.1
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• pp.1-12
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• 2020

In the development of geodynamic structures such as subduction and rift zones, a weakening mechanism is essential for localized weak zone formation in the lithosphere. Shear heating, a weakening mechanism, generates short-wavelength temperature elevation in the lithosphere; the increased temperature can reduce lithospheric strength and promote its breakup. A two-dimensional elastoplastic extensional basin model was used to conduct benchmarking based on previous numerical simulation studies to quantitatively analyze shear heating. The amount of shear heating was investigated by controlling the yield strength, extensional velocity, and strain- and temperature-dependent weakening. In the absence of the weakening mechanism, the higher yield strength and extensional velocity led to more vigorous shear heating. The reference model with a 100-MPa yield strength and 2-cm/year extension showed a temperature increase of ~ 50 K when the bulk extension was 20 km (i.e., 0.025 strain). However, in the yield-strength weakening mechanism, depending on the plastic strain and temperature, more efficient weakening induced stronger shear heating, which indicates positive feedback between the weakening mechanism and the shear heating. The rate of shear heating rapidly increased at the initial stage of deformation, and the rate decreased by 80% as the lithosphere weakened. This suggests that shear heating with the weakening mechanism can significantly influence the strength of relatively undamaged lithosphere.