• 한국학교수학회논문집
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• 제6권2호
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• pp.101-115
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• 2003

DES는 수학의 치환을 사용한 암호 알고리즘이다. 현재는 이를 개선한 AES가 표준화되어 사용되고 있다. 본 논문에서는 중 고등학교의 특별활동 자료로 사용할 수 있도록 DES를 소개하고 이의 구현을 시도하였다. 특히 한글의 처리를 할 수 있도록 하였다. 수학의 간단한 이론이 현대의 복잡한 정보화 사회에서 첨단 기술로 사용하고 있음을 알 수 있다.

• 조형예술학연구
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• 제5권
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• pp.67-86
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• 2003

In der vorliegenden Arbeit geht es um die Rezeptionsproblem des Bildes im Zeitalter der neuen Median. Heuzutage erleben wir einen Medien-Boom, bzw. digital-Medien. Manche Theoretiker diskutieren deshalb ueber das Problem der digital-Median in den verschiedenen Bereich. Im Bereich der Kunst und Kultur handelt os sich auch urn die Varaenderung des Kunstwerkes, der Rezeption und der Herstellung des Kunstwerkes. In dieser Fragestellung ist es wichtig, das Problem ueber Bild zu erlaeutern, weil das Bild abhaengig von den Medien ist. Durch Medien wird das Bild veraendern koennen. Und auch wird die Rezeption des Bildes veraendern muessen. In Zeitalter der neunen Medien, bzw digital Medien, veraenderten sich die Rezeption des Bildes von der konzentrativen Rezeption zur zerstreuuten und konzentrativen Rezeption. Diese erneuerte Rezeption nenne ich das zerstreuute Kontemplation. Das ist eine Rezeption im Zeitalter der neuen Medien.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제30회 춘계학술대회논문집
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• pp.343-346
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• 2008

초음속 주 유동내 연료의 수직분사 유동장에 대한 비정상 3차원 수치해석이 DES 난류 모델을 이용하여 수행되었다. 해석 결과는 시간에 따른 에디의 위치 및 에디 생성 빈도에 대하여 실험과 비교되었다. DES 난류 모델은 에디의 대류 특성을 비교적 정확하게 모사하고 있는 반면에 에디 생성 빈도는 다소 과대 예측하고 있다.

• 한국전산유체공학회지
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• 제11권2호
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• pp.25-31
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• 2006

A two-dimensional backward facing step flow is simulated by using URANS and Detached Eddy Simulations(DES) approaches. Turbulence models adopted for URANS and DES simulations are Spalart-Allmaras(S-A) model and Shear Stress Transport(SST) model. The target flow with ER=1.125, $Re_H=37,500$ is experimentally studied by Driver & Seegmiller. Various versions of DES have been tested in this paper. Results of the simulations are compared with the experimental data available to evaluate the merits and demerits of URANS and several versions of DES. URANS simulation converges to a steady state and hence unsteady characteristics are not featured. DES simulations in general successfully mimic large scale structures and oscillation characteristics of the flow.

• 한국군사과학기술학회지
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• 제14권2호
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• pp.238-245
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• 2011

We suggest a DES key expansion algorithm which is strong enough to overcome Differential Cryptanalysis(DC) and Linear Cryptanalysis(LC). Checking the weak points of DES, we found that the opened S box provide all information on the various kinds of attack. Using the key expansion we redesigned the S box which is not open to anybody who has no key. DC and LC can not be applied to the suggested algorithm without the redesigned S box information. With the computer experiments we show that the efficiency of this algorithm is almost the same as that of DES with respect to the crypto speed.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.114-117
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• 2007

DES is an improvement of the algorithm Lucifer developed by IBM in the 1977. IBM, the National Security Agency (NSA) and the National Bureau of Standards (NBS now National Institute of Standards and Technology NIST) developed the DES algorithm. The DES has been extensively studied since its publication and is the most widely used symmetric algorithm in the world. But nowadays, Triple DES (TDES) is more widely used than DES especially in the application in case high level of data security is required. Even though TDES can be implemented based on standard algorithm, very high speed TDES codec performance is required to process when encrypted high resolution satellite image data is down-linked at high speed. In this paper, Intel SSE2 (Streaming SIMD (Single-Instruction Multiple-Data) Extensions 2 of Intel) is applied to TDES Decryption algorithm and proved its effectiveness in the processing time reduction by comparing the time consumed for two cases; original TDES Decryption and TDES Decryption with SSE2

• Smart Structures and Systems
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• 제9권4호
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• pp.303-311
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• 2012

The possibility of suppressing critical speeds by using electromagnetic actuators (EMAs) is assessed experimentally in this paper. The system studied is composed of a horizontal flexible shaft supported by two ball bearings at one end and one roller bearing that is located in a squirrel cage at the other end. Four identical EMAs supplied with constant current are utilized. The EMAs associated to the squirrel cage constitutes the hybrid bearing. Results obtained, show that the constant current, when applied to the EMAs, produces a shift of the first critical speed toward lower values. Moreover, the application of constant current for a speed interval around the critical speed enables a smooth run-up or run-down without crossing any resonance.

• JSTS:Journal of Semiconductor Technology and Science
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• 제10권2호
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• pp.143-151
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• 2010

In this work, we propose a single electron memory 'SEM' design which consist of two key blocs: A memory bloc, with a voltage source $V_{Mem}$, a pure capacitor connected to a tunnel junction through a metallic memory node coupled to the second bloc which is a Single Electron Transistor "SET" through a coupling capacitance. The "SET" detects the potential variation of the memory node by the injection of electrons one by one in which the drainsource current is presented during the memory charge and discharge phases. We verify the design of the SET/SEM cell by the SIMON tool. Finally, we have developed a MAPLE code to predict the retention time and nonvolatility of various SEM structures with a wide operating temperature range.

• Nuclear Engineering and Technology
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• 제38권8호
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• pp.733-752
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• 2006

Severe accidents in PWRs are characterized by a continuously changing geometry of the core due to chemical reactions, melting and mechanical failure of the rods and other structures. These local variations of the porosity and other parameters lead to multi-dimensionnal flows and heat transfers. In this paper, a comprehensive set of multi-dimensionnal models describing heat transfers, thermal-hydraulics and melt relocation in a reactor vessel is presented. Those models are suitable for the core description during a severe accident transient. A series of applications at the reactor scale shows the benefits of using such models.

• 정보보호학회논문지
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• 제5권1호
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• pp.25-36
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• 1995

Differential Cryptanalysis(DC) 및 선형암호분석 공격방법은 DES와 같은 비밀키 암호시스템을 실질적으로 공격할 수 있는 효과적인 방법들이다. 본 논문에서는 DC 및 선형암호분석을 통한 DES의 취약점을 분석하고 이를 보완할 수 있는 효과적인 80비트 블록 암호시스템을 설계하였다. 설계된 암호알고리즘은 DES보다 일반 특성과 DC 및 선형암호분석 공격에 대한 비도를 향상시킨 것으로 분석되었다.