• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.184-188
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• 1989

This paper presents a fast realistic method based on a P-Q decoupled linearized model for contingency analysis. This method involves new idea to correct the errors caused by neglecting the resistance of transmission lines and/or by linearizing the model. The idea is to use fast correction method of errors by the principle of superposition for compensating these errors. Results demonstrating the effectiveness of the method on 25-bus model system and IEEE30-model system are presented

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.147-149
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• 2000

This paper describes a power flow method for distribution systems, applying the method of symmetrical component to back/forward sweep method. The proposed algorithm is effective for unbalanced radial distribution system, with process of distributed resource(PQ & PV node), AVR(Auto Voltage Regulator), shunt capacitor. This proposed method compared conventional back/forward sweep method with the using three phase unbalanced distribution systems with 34 nodes.

• Journal of the Korea Convergence Society
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• v.10 no.12
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• pp.143-149
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• 2019

Radiologist image perceived by radiology students plays important role for them in establishing a positive Radiology professionalism as well as having a satisfaction on their job. Thus, this study was conducted to examine the image of Radiologist perceived by both radiology students. Q-methodology was used for this study. 110 Q statements were extracted from qualitative survey from 110 radiology students. The selected statements were reviewed and revised by experts and 33 Q samples were finally selected. Then, 30 radiology students were recruited for this study and were asked to arrange the statement cards on a 9 point scale, which shaped a normal distribution. The data were then analyzed by using PQ method program. As a result, two types of Radiologist's images were explored: 'professional technology type', 'safety of patient type' The results of this study will be helpful to provide the direction that we have to pursue regarding educational and political perspectives.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.5
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• pp.185-189
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• 2012

It is almost impossible to directly find the prime factor, p,q of a large semiprime, n=pq. So Most of the integer factorization algorithms uses a indirect method that find the prime factor of the p=GCD(a-b,n),q=GCD(a+b,n) after getting the congruence of squares of the $a^2{\equiv}b^2$(mod n). Many methods of getting the congruence of squares have proposed, but it is not easy to get with RSA number of greater than a 100-digit number. This paper proposes a fast algorithm to get the congruence of squares. The proposed algorithm succeeded in getting the congruence of squares to a 19-digit number.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.4
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• pp.745-752
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• 2005

In this paper we propose and implement a digital part of a receiver system for identifying a moving object and its tracking position in wireless environment. We assumed UWB(Ultra Wide Band)-based communication system for target application and used serial communication method(RS-232). The proposed digital receiver consists of RS-232-type1/RS-232-type2 for input and output of serial communication, ID Detector for detecting IDs, and PISO&Buffer circuit to buffer input signals for appropriate operation of ID Detector. We implemented the digital receiver with minimal hardware(H/W) resource according to target application of UWB-based communication system. So it correlates input patterns with pre-stored patterns though repeated detecting method for multiple IDs. Since it has reference panerns in the Ve-stored form, it can detect various IDs instantly. Also we can program content and size of reference patterns considering compatibility with other systems .The implemented H/W was mapped into XC2S100PQ208-5 FPGA of Xilinx, occupied 727($30\%$) cells, and stably operated in the clock frequency of 75MHz(13.341ns).

• Journal of Digital Convergence
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• v.17 no.4
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• pp.167-176
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• 2019

This study was conducted to determine the types of nurse's image in nurses and nursing students by using Q-methodology. Total 40 Q-samples were extracted from Q-population consisted of the 385 statements, which were collected from 135 nurses with more than one year clinical experience in H city and 250 nursing students at H university. The Q-sample classification was conducted by 10 nurses and 40 nursing students, and data were analyzed by using PQ method program. As results, the types of nurse's images were derived as 'textbooked', 'realistic' and 'periodic.' This study was meaningful in analyzing the types of nurse image from both nurses and nursing students. In order to improve the image of nurses, we propose not only to develop a systematic nursing curriculum but also to develop health and medical policies reflecting reality of care settings.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.304-306
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• 2002

This paper presents a new method to characterize sag event. Power quality monitoring algorithm to analyze PQ problems is described. This paper shows that conventional characterizing method which makes use of only sag magnitude and sag duration has some limitations. It characterizes non-rectangular sag as more severe one. In addition, it can't count on voltage tolerance characteristics of each apparatus. In order to solve these problems, this paper present a new characterizing method and it properly characterizes non-rectangular sag considering the voltage tolerance characteristics.

• Journal of Electrical Engineering and Technology
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• v.10 no.6
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• pp.2442-2447
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• 2015

Because an electric railway vehicle is a large scale moving load, it can cause various kinds of power quality problems in the railroad power system. The power quality impacts are considered as the strong instantaneous stresses to the related power systems and can cause an accelerating aging and a malfunction of the power supplying components. Therefore, it is necessary to detect the small and intermittent symptoms mixed in the voltage waveform. However, they cannot be detected by the triggering functions of the existing power analyzers installed in the railway systems. This paper will examine the drawback of some fast detection tools and propose an advanced detecting and analyzing method based on a combined TEO and STFT algorithm.

• Journal of the Semiconductor & Display Technology
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• v.2 no.2
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• pp.31-37
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• 2003

This paper presents a measurement system of mechanical property using dual servo system. There are many kinds of method to measure material properties such as tensile test, indention and bending test. It is highly required to measure the properties of nano-sized material and structure. However, It is need more accurate measurement system, more stable and frequency response than conventional test. In this paper, we designed the dual servo system for a measuring instrument The dual servo system consisting of a coarse stage and a fine motion stage with VCM and PZT is proposed. Mechanical mechanism is designed with the leaf spring type of flexure hinge joint. Lead compensator is applied to this control system, and is designed by PQ method.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.11
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• pp.531-535
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• 2000

A method to compute the reactive powers of the added buses by the decoupled UPFC model for the optimal voltage profile is presented, by which the voltage magnitudes of PQ buses can get closer to the reference value(usually one p.u.). The performance index for assessing how much the voltage magnitude is closer to the reference value is defined as the squared sum of the present voltage minus the reference voltage multiplied by the weighting number associated with the relative importance of the buses. Numerical example in a 10-unit 39-bus power system with 2 UPFC's shows that the performance index can be very much reduced by operating many UPFC's with the reactive powers for the optimal voltage profile proposed in this paper.