• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.23-24
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• 2008

• Journal of the korean Society of Automotive Engineers
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• v.26 no.2
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• pp.10-16
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• 2004

일반적으로 기구라 함은 어떤 한정된 상대운동을 할 수 있도록 각종 Joint로 연결된 여러 강체들의 조합을 의미한다. 또한 기구는 많은 기계적 장치들의 가장 중요한 설계인자중의 하나라 할 수 있는 기하학적 특성들을 구현할 수 있도록 구성되어지며, 그 기하학적 특성은 주로 주 관심 대상인 강체의 기준 강체에 대한 궤적 특성이라 할 수 있겠다.(중략)

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.1
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• pp.96-107
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• 1996

A voice personality transformation algorithm using orthogonal vector space conversion is proposed in this paper. Voice personality transformation is the process of changing one person's acoustic features (source) to those of another person (target). In this paper, personality transformation is achieved by changing the LPC cepstrum coefficients, excitation spectrum and pitch contour. An orthogonal vector space conversion technique is proposed to transform the LPC cepstrum coefficients. The LPC cepstrum transformation is implemented by principle component decomposition by applying the Karhunen-Loeve transformation and minimum mean-square error coordinate transformation(MSECT). Additionally, we propose a pitch contour modification method to transform the prosodic characteristics of any speaker. To do this, reference pitch patterns for source and target speaker are firstly built up, and speaker's one. The experimental results show the effectiveness of the proposed algorithm in both subjective and objective evaluations.

• Korean Journal of Optics and Photonics
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• v.3 no.1
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• pp.27-36
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• 1992

Frequency modulation spectroscopy of the super-cavity, of which finesse is app. 40,000 has been demonstrated by using a sigle mode He-Ne laser. In-phase and quardrature components of frequency modulation signals (FM signal) were obtained by using the 1.5 MHz-driven-electrooptic phase modulator. The vector locus of the FM signa in the phase space, which is consisted of in-phase and quardrature components of the FM signal, was observed and analyzed for the dependence of FM signal upon the phase of the reference signal of a phase-sensitive-detector. According to rotating the phase of the reference signal, the vector locus was observed to rotate with the same phase angle as the reference signal. The in-phase component of the FM signals will be used to stabilize the frequency of the He-Ne laser to the resonant frequency of the super-cavity.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.12
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• pp.1124-1132
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• 2011

This paper deals with smooth path generation using B-spline for fixed-wing unmanned aerial vehicles manuevering in 2D environment. Hexagonal cell representation is employed to model the 2D environment, which features increased connectivity among cells over square cell representation. Subsequently, hexagonal cell representation enables smoother path generation based on a discrete sequence of path from the path planner. In addition, we present an on-line path smoothing algorithm incorporating B-spline path templates. The path templates are computed off-line by taking into account all possible path sequences within finite horizon. During on-line implementation, the B-spline curves from the templates are stitched together repeatedly to come up with a reference trajectory for UAVs. This method is an effective way of generating smooth path with reduced on-line computation requirement, hence it can be implemented on a small low-cost autopilot that has limited computational resources.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.5
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• pp.634-642
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• 1993

In this paper a new trajectory control method is proposed for a robot manipulator using a time delay neural network(TDNN) as a feedforward controller with an algorithm to learn inverse dynamics of the manipulator. The TDNN structure has so favorable characteristics that neurons can extract more dynamic information from both present and past input signals and perform more efficient learning. The TDNN neural network receives two normalized inputs, one of which is the reference trajectory signal and the other of which is the error signals from the PD controller. It is proved that the normalized inputs to the TDNN neural network can enhance the learning efficiency of the neural network. The proposed scheme was investigated for the planar robot manipulator with two joints by computer simulation.

• Journal of Advanced Navigation Technology
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• v.10 no.2
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• pp.113-120
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• 2006

In this paper, a vision-based robust controller for tracking the desired trajectory a robot manipulator is proposed. The trajectory is generated to move the feature point into the desired position which the robot follows to reach to the desired position. To compensate the parametric uncertainties of the robot manipulator which contain in the control input, the robust controller is proposed. In addition, if there are uncertainties in the Jacobian, to compensate it, a vision-based robust controller which has control input is proposed as well in this paper. The stability of the closed-loop system is shown by Lyapunov method. The performance of the proposed method is demonstrated by simulations and experiments on a two degree of freedom 5-link robot manipulators.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.5
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• pp.533-541
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• 2011

This paper presents a frequency-response test performed on an antagonistic actuation system consisting of two Mckibben pneumatic artificial muscles and a pneumatic circuit with pressure valves. Varying switching frequency to pressure valves from 0.1 Hz to 5 Hz, parameters of a linear model were estimated optimally to predict dynamic characteristics of the antagonistic actuation. A model-base control scheme with estimated parameters was built for the precise trajectory tracking of the antagonistic structure and realized on a reconfigurable embedded control system, CompactRIO. Experimental results showed that the proposed model-based control scheme gave good performance in trajectory tracking comparing with a PD control scheme when square wave and sinusoidal wave were given as references to follow.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.764-765
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• 2017

A trajectory analysis program was developed using a 3 DOF model to analyze KSLV-II performance with the reducing weight. The program estimates the injection performance on the SSO orbit, which is determined as payload weight for the orbit, with various vehicle structural ratios. The KSLV-II can transport 2.58 ton to the target orbit with a reduced structural ratio similar to the Angara rockets.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.05a
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• pp.233-235
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• 2022

서비스 제공자는 사용자의 위치를 기반으로 용이한 정보를 제공한다. 과거에는 사용자가 질의를 요청하는 순간(snapshot)에 대해 사용자의 위치를 보호하는 기법들이 주를 이루었다면 최근에는 연속적인 질의를 요청할 때 사용자의 위치를 보호하는 기법들이 연구되고 있다. 그러나 연속적인 질의처리는 시간별로 요청되는 질의의 묶음으로서 영역을 보호할 수 있으나 영역을 연결할 경우 사용자의 궤적이 노출되는 문제가 발생할 수 있다. 가장 최근 연속적인 질의에서 이동 궤적을 보호하는 k-ATY가 제안되었지만 사용자와 동일한 이동 속도와 일정한 방향을 기준으로 더미를 생성하기 때문에 장애물(다리, 건물 등)이 있을 경우 더미의 위치가 노출될 수 있다. 본 논문에서는 이러한 문제점을 개선하기 위하여 장애물을 고려한 k-oATY 기법을 제안하고 기존기법과 비교한다.