• ETRI Journal
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• 제26권6호
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• pp.635-640
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• 2004

A new low-complexity differential detection technique, fractional multi-bit differential detection (FMDD), is proposed in order to improve the performance of continuous phase modulation (CPM) signals such as Gaussian minimum shift keying (GMSK) and Gaussian frequency shift keying (GFSK). In comparison to conventional one-bit differential detected (1DD) GFSK, the FMDD-employed GFSK provides a signal-to-noise ratio advantage of up to 1.8 dB in an AWGN channel. Thus, the bit-error rate performance of the proposed FMDD is brought close to that of an ideal coherent detection while avoiding the implementation complexity associated with the carrier recovery. In the adjacent channel interference environment, FMDD achieves an even larger SNR advantage compared to 1DD.

• 대한산업공학회지
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• 제12권1호
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• pp.95-105
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• 1986

This paper presents an adaptive algorithm to generate a near-optimal closed-loop solution for a non-zero sum differential game by periodically updating the solutions of the two-point boundary-value problem. Applications to competitive advertising problem show that the adaptive algorithm can be used as an efficient tool to solve the differential game problem in which one player may take advantage of the other's non-optimal play.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.1227-1233
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• 1993

In this paper we present the differential geometric approach for the analysis and design of sliding modes in nonlinear variable structure feedback systems. We also design the robust controller for the nonlinear system using variable structure control theory on the basis of differential geometric methods and feedback linearization applying Min-Max control based on the Lyapunov second method. The robustness against parameter uncertainties for robot manipulators with flexible joint is considered. Simulation results are presented and show the advantage of the proposed nonlinear control method.

• JSTS:Journal of Semiconductor Technology and Science
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• 제2권1호
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• pp.7-18
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• 2002

Single-ended differential RF circuit topologies fully utilizing complementary characteristics of both NMOS and PMOS are proposed, which have inherent advantage of both single-ended and differential circuits. Using this concept, we propose a CCPP (Complementary CMOS parallel push-pull) amplifier which has single-ended input/output with differential amplifying characteristics, leading to more than 30 dB improvement on $IIP_2$. In addition, complementary resistive mixer is also proposed, which provides not only differential IF outputs from single-ended RF input, but much better linearity as well as isolation characteristics. Experimental results using $0.35{\;}\mu\textrm{m}$ CMOS process show that, compared with conventional NMOS resistive mixer, the proposed mixer shows 15 dB better LO-to-IF isolation, 4.6 dB better $IIP_2$, and 4.5 dB better $IIP_3$performances.

• Structural Engineering and Mechanics
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• 제72권4호
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• pp.491-502
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• 2019

This paper explores the analytical buckling solution of rectangular thin plates by the finite integral transform method. Although several analytical and numerical developments have been made, a benchmark analytical solution is still very few due to the mathematical complexity of solving high order partial differential equations. In solution procedure, the governing high order partial differential equation with specified boundary conditions is converted into a system of linear algebraic equations and the analytical solution is obtained classically. The primary advantage of the present method is its simplicity and generality and does not need to pre-determine the deflection function which makes the solving procedure much reasonable. Another advantage of the method is that the analytical solutions obtained converge rapidly due to utilization of the sum functions. The application of the method is extensive and can also handle moderately thick and thick elastic plates as well as bending and vibration problems. The present results are validated by extensive numerical comparison with the FEA using (ABAQUS) software and the existing analytical solutions which show satisfactory agreement.

• 한국항행학회논문지
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• 제19권1호
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• pp.48-52
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• 2015

본 논문에서는 2011년에 제안된 암호와 복호가 동일한 블록 암호 SSB에 대한 차분 오류 공격을 제안한다. 이 알고리즘은 국제표준 블록암호를 기반으로 설계된 블록 암호로써 하드웨어 구현에서 장점을 갖게 설계되었다. 차분 오류 공격은 부채널 공격 기법 중 하나로 오류 주입 공격과 차분 공격을 결합한 것이다. SSB는 하드웨어 환경에 적합한 알고리즘이므로 차분 오류 공격에 대해 안전성을 가져야 한다. 그러나 본 논문에서 제안하는 차분 오류 공격을 이용하면, 1 개의 랜덤 바이트 오류를 주입과 $2^8$의 전수조사를 통해 SSB의 128 비트 비밀키를 복구할 수 있다. 이 결과는 암호와 복호가 동일한 블록 암호 SSB의 안전성을 분석한 첫 번째 결과이다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2001년도 Proceeding of KIN-CIN Joint Symposium 2001 on Satellite Navigation/AIS, lntelligence , Computer Based Marine Simulation System and VDR
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• pp.81-87
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• 2001

In this article, we have done some analysis about the collision-avoidance specialty of “pressing complexion” and “pressing danger”in the meet process of two boats, and offered a mathematic model of differential coefficient countermeasure decision for collision-avoidance, which adapt to the right complexion. The basal idea is, in the right condition whatever do the coming boat do, and our boat will always adept dynamic, continuous and the best countermeasure. When both the controlling capabilities of two boats have advantage and inferior position, we can working-out with the qualitative differential coefficient countermeasure.

• 한국정밀공학회지
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• 제18권3호
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• pp.205-215
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• 2001

Continuously variable transmission(CVT) mechanisms considered here combine the functions of a 2K-H I type differential gear unit and a V-belt continuously variable unit(CVU). One shaft of the V-belt CVU is connected directly to the differential gear unit and remaining shaft of it is linked to the output shaft. These mechanisms have many advantage which are the decrease of CVT size, the increase of overall efficiency, the extension of speed ratio range, and the generation of geared neutral. In this paper six different mechanisms of output coupled type CVT are proposed. Some useful theoretical formula related to speed ratio, power flow and efficiency are derived and analyzed, and theoretical analysis are proven by various experiments.

• 대한지리학회지
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• 제47권1호
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• pp.140-157
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• 2012

세계화 시대에도 대부분의 세계인들은 각 지역이나 지방이 정체성을 지니고 공생관계 속에서 평화롭게 살기를 원한다. 이러한 관점에서, 세계의 도시 또는 산업지역 간의 글로벌 경쟁력 강화에 초점을 둔 신산업지구, 산업클러스터, 지역혁신체제, 세계도시지역과 같은 신지역주의 발전론은 세계의 몇몇 선진 산업지역에서 유도된 것으로 보편적 지역발전론이 될 수 없다. 본 연구는 대안적 지역발전론으로서 지역차이발전론의 개발을 시도했다. 지역차이발전론은 현실세계에 존재하는 지역 간의 차이 또는 상이한 산업발전이 세계인의 공생과 지역 정체성과 같은 두 가지 핵심적인 발전 가치를 내포하고 있음을 중시한다. 지역차이발전론은 지역의 지리적 요소 중에서 차이우위를 지닌 요소를 기반으로 이에 적합한 지역의 차별적 산업발전을 추구하는 것으로서, 지역의 지리적 요소 중 지역 간에 현저한 차이를 보이고 있는 위치, 자연환경(지형, 토양, 기후 등), 천연자원, 인구, 교통, 문화, 경관의 차이우위를 중요시 한다. 그리고 지역차이발전이 성공적으로 이루어지기 위해서는 정부, 기업, 관련 기관, 지역주민과 같은 네 주체가 발전목표를 공유하고 협력과 갈등 관계 속에서 상보적 역할을 적극적으로 수행하는 것이 관건이다. 이 이론은 많은 경험적인 연구를 통해 이론의 보편적 타당성을 확보하는 것이 향후 과제이다.

• Smart Structures and Systems
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• 제5권3호
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• pp.279-290
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• 2009

Two degrees of freedom resonant systems are employed to improve the resonant property of resonant sensor, as compared to a single degree of freedom resonant system. This paper presents design, development and testing of two degrees of freedom resonant sensor. To measure absolute mass, cantilever shaped two different masses (smaller/absorber mass and bigger/drive mass) with identical resonant frequency are mechanically linked to form 2 - Degree-of-Freedom (DOF) resonator which exhibits higher amplitude of displacement at the smaller mass. The same concept is extended for measuring differential quantity, by having two bigger mass and one smaller mass. The main features of this work are the 3 - DOF resonator for differential detection and the microcontroller based closed loop electronics for resonant sensor with piezoelectric sensing and excitation. The advantage of using microcontroller is that the method can be easily extended for any range of measurand.