• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.8
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• pp.1334-1341
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• 2008

This paper introduces an approach of Hybrid Particle Swarm Optimization(HPSO) for a security-constrained economic dispatch(SCED) with line flow constraints. To reduce a early convergence effect of PSO algorithm, we proposed HPSO algorithm considering a mutation characteristic of Genetic Algorithm(GA). In power system, for considering N-1 line contingency, we have chosen critical line contingency through a process of Screening and Selection based on PI(performance Index). To prove the ability of the proposed HPSO in solving nonlinear optimization problems, SCED problems with nonconvex solution spaces are considered and solved with three different approach(Conventional GA, PSO, HPSO). We have applied to IEEE 118 bus system for verifying a usefulness of the proposed algorithm.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2007.11a
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• pp.444-448
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• 2007

이차원바코드 기술과 암호화 알고리즘을 이용하여 문서의 위${\cdot}$변조 등을 방지하고 문서의 상태를 기업체나 공공기관 등에서 쉽게 확인하여 판단할 수 있는 시스템을 제안한다. 모든 위${\codt}$변조 확인이 필요한 문서에 암호화된 이차원바코드를 첨부한다. 확인자 측에서는 첨부된 이차원 바코드를 바코드 리더기로 인식하거나 이차원 바코드의 사진을 관련 인터넷 웹 사이트를 통해 문서의 위${\cdot}$변조를 판단한다.

• Journal of the Korea Society of Computer and Information
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• v.5 no.3
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• pp.91-98
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• 2000

In this paper we design implement the speaker verification system for verifying personal identification using voice. Filter bank magnitude was used as a feature parameter and code-book was made using LBG a1gorithm. The code book convert feature parameters into code sequence. The difference between reference pattern and input pattern measures using DTW(Dynamic Time Warping). The similarity measured using DTW and threshold value derived from deviation were used to discriminate impostor from client speaker.

• Journal of Positioning, Navigation, and Timing
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• v.10 no.2
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• pp.131-137
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• 2021

The Angle-of-Arrival (AOA) estimation in real time is one of core technologies for the real-time tracking system, such as a radar or a satellite. Although AOA estimation algorithms for various antenna types have been studied, most of them are for the single-shaped array antenna suitable to the specific frequency. In this paper, we propose the cascade AOA estimation algorithm for the combined array antenna with Uniform Rectangular Frame Array (URFA) and Uniform Circular Array (UCA), with the excellent performance for various frequencies. The proposed technique is consisted of Capon for roughly finding AOA groups with multiple signal AOAs and Beamspace Multiple Signal Classification (MUSIC) for estimating the detailed signal AOA in the AOA group, for the combined array antenna. In addition, we provide computer simulation results for verifying the estimation performance of the proposed algorithm.

• Korean Journal of Ecology and Environment
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• v.53 no.4
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• pp.336-343
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• 2020

Large-scale cultivation of Microcystis aeruginosa in different light conditions was conducted for verifying the cell growth in a greenhouse system. Environmental and chemical parameters of the large-scale culture medium were measured for analyzing the interaction between M. aeruginosa and its symbiotic bacteria. During cultivation, a difference in cell growth pattern was observed between control (natural light) and light-limited groups (reduction of blue, green, and blue/green light, respectively). Comparing the control group, the light reduced groups showed slow and delayed cell growth through the cultivation period. Also, there is differences in the consuming pattern of total nitrogen and total phosphorus which indicated that the possibility of interaction between M. aeruginosa and symbiotic bacteria.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.15 no.4
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• pp.232-239
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• 2015

Studies on the control of the inverted pendulum type system have been widely reported. This is because it is a typical complex nonlinear system and may be a good model for verifying the performance of a proposed control system. In this paper, we propose the design of some fuzzy logic control (FLC) systems for controlling a Segway-type mobile robot, which is an inverted pendulum type system. We first derive a dynamic model of the Segway-type mobile robot and then analyze it in detail. Next, we propose the design of some FLC systems that have good performance for the control of any nonlinear system. Then, we design two conventional FLC systems for the position and balance control of the Segway-type mobile robot, and we demonstrate their usefulness through simulations. Next, we point out the possibility of simplifying the design process and reducing the computational complexity,, which results from the skew symmetric property of the fuzzy control rule tables. Finally, we design two other FLC systems for position and balance control of the Segway-type mobile robot. These systems have only one input variable in the FLC systems. Furthermore, we observe that they offer similar control performance to that of the conventional two-input FLC systems.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.10
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• pp.78-88
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• 1990

To evaluate the performance of a multiprocessor system, a discrete event model of memory interference in the system employing multiple-bus interconnection networks is proposed. An analytic model of the system is presented and then simulator models are implemented for cross-verifying the analytic results and simulation results. The simulator model takes as input the number of processors, the number of memory modules, the number of buses and the local memory miss ratio. The model produces as output the memory bandwidth, the processor, memory module and bus utilization and the bus contention ratio. Using the model in the design of the system, it is possible to evaluate the system performance by analyzing the interaction of the input parameters.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.1331-1334
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• 2002

Micropayment is an electronic payment system for small value transaction. It needs to use a little amount of resources, such as communication and computation due to its small value. In other words, the processing cost for the micropayment must be less than the value of the payment. Several kinds of transactions are suitable for micropayment, eg. the purchasing of train tickets or digital newspapers. Since micropayment systems are designed for small-amount payment the key factor for any micropayment system design is believed to be the minimization of resource consumption without compromising the standard security. In this paper, we propose an adaptive agent approach to credit-based micropayment system, which employs the concept of dynamic balancing between the resource consumption and the risk in the system. As a result of the dynamic balancing, our system not only solves the problem of global overspending but also uses fewer amount of resources than existing approaches. Our approach limits the amount of money spent by untrusted customers to all merchants. Thus, our approach provides a boundary of the global overspending. In addition, for trusted customers, our approach requires less scale of communication for verifying authorizations than all existing approaches.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.10a
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• pp.165-170
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• 2000

Port State Control (PSC) is the inspection of foreign ships in national ports for the purpose of verifying th\ulcorner the condition of the ships and its equipments comply with the requirement of international conventions and the ship is manned and operated in compliance with applicable international laws. On the other hand, check items in PSC are nearly similar to periodical survey of Classification Societies, because they have the same background regarding safety and maritime pollution prevention. The purpose of this study is to develope computer-aided information systems for ship inspection item which is useful for effective implementation of Port State Control. For this work, the status of PSC is reviewed, and the related scheme of ship survey system in Classification Societies is investigated. On these bases, a computer software integrated database system and object-oriented technique is developed. The developed system is expected helpful to establish and maintain an effective system of Port State Control.

• Journal of Power Electronics
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• v.18 no.3
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• pp.892-901
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• 2018

SiC MOSFETs have been used to improve system efficiency in high frequency converters due to their extremely high switching speed. However, this can result in undesirable parasitic oscillations in practical systems. In this paper, models of the key components are introduced first. Then, theoretical formulas are derived to calculate the switching oscillation frequencies after full turn-on and turn-off in clamped inductive circuits. Analysis indicates that the turn-on oscillation frequency depends on the power loop parasitic inductance and parasitic capacitances of the freewheeling diode and load inductor. On the other hand, the turn-off oscillation frequency is found to be determined by the output parasitic capacitance of the SiC MOSFET and power loop parasitic inductance. Moreover, the shifting regularity of the turn-off maximum peak voltage with a varying switching speed is investigated on the basis of time domain simulation. The distortion of the turn-on current is theoretically analyzed. Finally, experimental results verifying the above calculations and analyses are presented.