• Journal of Industrial Technology
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• v.15
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• pp.63-70
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• 1995

This paper presents an impact control algorithm for reducing the potentially damaging effects by interation of redundant manipulators with their environments. In the proposed control algorithm, the redundancy is resolved at the torque level by locally minimizing joint torque, subject to the operational space dynamic formulation which maps the joint torque set into the operational forces. For a given pre-impact velocity of the manipulator, the proposed approach is on generating joint space trajectories throughout the motion near the contact which instantaneously minimize the impulsive force which is a scalar function of manipulator's configurations. The comparative evaluation of the proposed algorithm with a local torque optimization algorithm with a local torque optimization algorithm without reducing impact is performed by computer simulation. The simulation results illustrate the effectiveness of the algorithm in reducing both the effects of impact and large torque requirements.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06a
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• pp.118-120
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• 2006

최신 GPU는 일반 CPU보다 10배 이상 빠른 연산능력을 갖추고 있는데다가 사용자가 직접 프로그래밍 할 수 있기 때문에 이를 이용한 고속 볼륨 렌더링 알고리즘에 대한 연구가 활발하게 진행되고 있다. 그러나 스트림 프로세싱에 특화 돼있는 GPU의 특성상 early ray termination과 empty space skipping을 구현하는 것이 쉽지만은 않다. 특히 지금까지 제안됐던, 프록시 도형(proxy geometry)을 사용하는 볼륨 렌더링 알고리즘은 empty space skipping은 비교적 효율적으로 구현하지만 early ray termination의 지원은 상대적으로 미비했다. 본 논문에서는 스텐실 버퍼와 OpenGL 확장(extension)을 이용한 2-Pass 알고리즘을 통해서 early ray termination과 empty space skipping을 동시에 구현하는 방법을 제시하고, 그 성능을 측정했다.

• Proceedings of the KAIS Fall Conference
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• 2005.05a
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• pp.198-201
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• 2005

본 논문에서는 직류전동기의 속도 및 전류제어를 위하여 dSPACE 시스템을 이용하여 전류 궤환을 갖는 속도 제어시스템을 구현하였다 속도 및 전류제어기의 설계는 MATLAB/SIMULINK 프로그램을 사용하여 간편하고 손쉽게 구현하였으며 직류전동기 속도제어의 안정성과 응답성을 향상시킬 수 있었다. 직류전동기의 전류제어 및 속도제어는 DSP 보드와 dSPCE 시스템을 사용하여 수행하였으며, 속도의 궤환은 속도센서인 엔코더 펄스를 이용해서 QEP로 처리하였고 전류의 궤환은 전류센서인 홀센서를 통해서 A/D 변환기로 처리하였다. 제어기들은 각각 PI 속도제어기 및 PI 전류제어기를 설계하였고 시뮬레이션과 실험을 통해서 속도 및 전류 응답을 확인하였다.

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.5
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• pp.1-8
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• 2018

This paper proposes a simple encryption technology for space-time block coding algorithm. Space-time block coding algorithm uses two antennas in transmitting data which consists of original data and transformed data for the purpose of combining in the receiver. This kind of two transmission antenna data could be exchanged and transmitted on each other's antenna individually, which can be used as a simple encryption algorithm. Encryption timing control informations should be shared between transmitter and receiver beforehand. It is shown that the proposed architecture can give performance enhancement compared with no encryption cases.

• Geophysics and Geophysical Exploration
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• v.7 no.1
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• pp.19-24
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• 2004

Frequency-space domain full-wave tomography is a promising technique for delineating detailed subsurface structure with high resolution. However, this method requires criteria for the selection of a set of optimal temporal frequency components, to achieve stability in the sequence of inversion processes together with computational efficiency. We propose a method of selecting optimal temporal frequencies, based on wavenumber continuity. The proposed method is tested numerically and is shown to be able to select an optimal set of frequency components that are sufficient to image the anomalies.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2017.11a
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• pp.1321-1321
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• 2017

Recently the attention to the 4th industrial revolution has been increasing. In the 4th industrial revolution era, the boundaries of physical space, digital space, and biological space are becoming blurred since the active convergence between various fields There are a lot of issues on the 4th industrial revolution such as artificial intelligence, internet of thing, big data, and cyber physical system. Accordingly, this study aims to analyse the main issues of the 4th industrial revolution. Data mining such as topic modelling method is used for the analysis. This study is expected to be helpful for the researcher and policy maker of the 4th industrial revolution.

• Journal of National Security and Military Science
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• s.2
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• pp.285-314
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• 2004

The forms of current war are diversified over the pan-national industry. Among these, one kind of threats which has permeated the cyber space based on the advanced information technology causes a new type of war. C4ISR, the military IT revolution, as a integrated technology innovation of Command, Control, Communications, Computer, Intelligence, Surveillance and Reconnaissance suggests that the aspect of the future war hereafter is changing much. In this paper, we design the virtual decoy system and intrusion trace marking mechanism which can capture various attempts and evidence of intrusion by hackers in cyber space, trace the penetration path and protect a system. By the suggested technique, we can identify and traceback the traces of intrusion in cyber space, or take a legal action with the seized evidence.

• East Asian mathematical journal
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• v.31 no.1
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• pp.65-75
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• 2015

In modern times, coupled fixed point theorems have been rigorously studied by many researchers in the milieu of partially ordered G-metric spaces using different contractive conditions. In this note, some coupled fixed point theorems using mixed monotone property in partially ordered G-metric spaces are obtained. Furthermore some theorems by omitting the completeness on the space and continuity conditions on function, are obtained. Our results partially generalize some existing results in the present literature. To exemplify our results and to distinguish them from the existing ones, we equip the article with suitable examples.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.1
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• pp.77.2-77.2
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• 2013

xIn the present work, we explored the effect of the radiation on the effective impact parameter for capture in a fully general relativistic manner. To summarize our results, evidently due to the radiation drag (the Poynting-Robertson effect), critical impact parameter of point particle gets larger by the factor of two, thus, the effective cross section of the luminous relativistic star becomes 4 times larger than that of the star without radiation emission. In addition, the finite size effect of the star adds up to this growth of the effective cross section.

• Journal of the Korea Institute of Military Science and Technology
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• v.6 no.3
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• pp.113-121
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• 2003

In this paper, the transmit antenna for the space feeder used for the phased array antennas is investigated. The multi-aperture horn antenna is proposed as the transmit antenna and the characteristics are verified with the Matlab coding, HFSS of Ansoft Corp., and MWS of CST Corp., The E-plane and H-plane beam patterns of the multi-aperture horn antenna are nearly symmetrical and the sidelobe level of the I-plane beam pattern is lower than that the of general pyramidal horn antenna. The fabricated multi-aperture horn antenna is measured using the near-field measurement system. The measured results show good agreement with the simulated ones.