• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 C
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• pp.1054-1056
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• 1999

It is the most important in small signal stability analysis of large scale Power systems to compute only the dominant eigenvalues selectively with numerical stability and efficiency. In this Paper evoluted linear analysis program, transformed state matrix using Inverse transformation with complex shift and then Hessenberg process and iterative scheme are used to accelerate Hessenberg process, can calculate dominant eigenvalues. In this Paper, The accuracy of this Program has been validated against 4-machines 11-bus system and New England 10-machines 39-bus system. Also applied to KEPCO system - about 791-bus 250-machines 2500-branches, got 2568 order state matrix, and calculated two dominant modes. This analysis result equaled to result of EPRI's SSSP program to use commonly, and calculating time is faster.

• 한국기계가공학회지
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• 제17권2호
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• pp.15-21
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• 2018

In this paper, a detection and warning system is proposed for the remaining kids in a school bus. For detecting the remaining kids, an ultrasonic sensor is used. The basic experiments of the ultrasonic sensor are performed, and a modified ultrasonic sensor is proposed. Also, the appropriate location of the ultrasonic sensor is proposed by considering various sitting positions. Based on the above kid detection system, a warning algorithm is designed. Using the above detection and warning system, experiments are performed. From the experimental results, it is found that the proposed system, based on the modified ultrasonic sensor, can detect the remaining kids in a school bus. The proposed system can also give an appropriate warning signal.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.732-735
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• 2006

Downtown cities in Japan are facing sharp fall in customers and continued shut down of shops due to decrease of population, increase in family cars and flowing of customers into the suburban large-scale retail stores. Omura City in Nagasaki Prefecture, Japan is no exception to this. For the revitalization of the downtown, many actions have been taken to open the vacant shops. However, transportation problem is the most important one to be solved for the citizens including the elderly people having difficulty in movement. Accordingly, this study was aimed at the revitalization of the downtown by substantiality public transportation. We have attempted to develop routes from the view-point of convenience by using Analytic Hierarchy Process (AHP) and Geographic Information Systems (GIS). As a result of the study, we were able to select three bus transportation areas by incorporating qualitative factors into the analysis. Finally, the study concluded that, revitalization activities of the downtown city itself is required in addition to re-structuring of bus transportation system for the revitalization of the downtown city.

• 대한전기학회논문지:전력기술부문A
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• 제48권9호
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• pp.1081-1087
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• 1999

Load Flow calulation methods can usually be divided into Gauss-Seidel method, Newton-Raphson method and decoupled method. Load flow calculation is a basic on-line or off-line process for power system planning. operation, control and state analysis. These days Newton-Raphson method is mainly used since it shows remarkable convergence characteristics. It, however, needs considerable calculation time in construction and calculation of inverse Jacobian matrix. In addition to that, Newton-Raphson method tends to fail to converge when system loading is heavy and system has a large R/X ratio. In this paper, matrix equation is used to make algebraic expression and then to slove load flow equation and to modify above defects. And it preserve P-Q bus part of Jacobian matrix to shorten computing time. Application of mentioned algorithm to 14 bus, 39 bus, 118 bus systems led to identical results and the same numbers of iteration obtained by Newton-Raphson method. The effect of computing time reduction showed about 28% , 30% , at each case of 39 bus, 118 bus system.

• 한국재료학회지
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• 제13권2호
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• pp.101-105
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• 2003

In this study, we have investigated the availability of the electroless Ni-B plating for a diffusion barrier of the bus electrode. The Ni-B layer of 1$\beta$: thick was electroless deposited on the electroplated Cu bus electrode for AC plasma display. The layer was to encapsulate Cu bus electrode to prevent from its oxidation and to serve as a diffusion barrier against Cu contamination of the transparent dielectric layer in AC plasma display. The microstructure of the as-plated barrier layer was made of an amorphous phase and the structure was converted to crystalline at about 30$0^{\circ}C$. The concentration of boron was about 5∼6 wt.% in the electroless Ni-B deposit regardless of DMAB concentration. The electroless Ni-B deposit was coated on the surface of the electroplated Cu bus electrode uniformly. And the electroless Ni-B plating was found to be an appropriate process to form the diffusion barrier.

• 자동차안전학회지
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• 제14권4호
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• pp.113-119
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• 2022

The structural safety of hydrogen buses is being evaluated for the successful introduction of hydrogen buses. The crash test methodology, for example, side impact test procedure is being discussed for hydrogen bus structure safety with a compressed hydrogen storage system located under the bus floor. Thus this study describes a new experiment method for side impact test with compressed hydrogen storage system independently based on finite element analysis instead of side impact test using full hydrogen bus. A side crash procedure of conceptual compressed hydrogen storage structure was investigated and impact simulations were performed. The finite element models of hydrogen bus, simplified structures, fuel tank system and side impact moving barrier were set up and simulation results reported model performance and result comparison of three different simplified models. Computational results and research discussion proposed the fundamental test framework for safety assessment of the compressed hydrogen storage system.

• Journal of Electrical Engineering and Technology
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• 제11권1호
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• pp.76-85
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• 2016

This paper presents a method of decision on where bus splitting is needed to reduce fault current level of power systems and to satisfy the fault current constraints. The method employs a modified fault current constrained optimal power flow (FCC-OPF) with X variables for the candidate locations of splitting and for decision making on whether to split or not, it adopts soft-discretization by augmenting inversed U-shaped penalty terms. Also, this paper discusses the procedure on the adequate selection of bus splitting locations based on the results of the modified FCC-OPF, to reduce the total number of the actions taken.

• JSTS:Journal of Semiconductor Technology and Science
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• 제11권1호
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• pp.33-39
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• 2011

H.264 decoders usually have pipeline architecture by a macroblock or a 4 ${\times}$ 4 sub-block. The period of the pipeline is usually fixed to guarantee the operation in the worst case which results in many idle cycles and higher data bandwidth. Adaptive pipeline architecture for H.264 decoders has been proposed for efficient decoding and lower the requirement of the bandwidth for the memory bus. However, it requires a controller for the adaptive priority control to utilize the advantage. We propose a smart bus arbiter that replaces the controller. It is introduced to adjust the priority adaptively the QoS (Quality of Service) control of the decoding process. The smart arbiter can be integrated the arbiter of bus systems and it works when certain conditions are met so that it does not affect the original functions of the arbiter. An H.264 decoder using the proposed architecture is designed and implemented to verify the operation using an FPGA.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전력기술부문
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• pp.28-30
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• 2003

Probabilistic Load Flow(PLF) solution based on the method of moments is used for security assessment of bus voltages in power systems. Bus voltages, line currents, line admittances, generated real and reactive power, and bus loads are treated as complex random variables. These complex random variables are known in terms of probability density functions(PDF). Also, expressions for the convolutions of complex random variables in terms of moments and cumulants have been derived. Proposed PLF solution using the method of moments is fast, because the process of convolution of various complex random variables is performed in moment and cumulant domain. Therefore, the method is applied to security assessment of power systems in this paper. Finally, system operator also can be used information of security assessment to improve reliability of power systems.

• 한국표면공학회지
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• 제49권5호
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• pp.447-453
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• 2016

In this study, we intended to extend the life of electropolishing solution through the reduction of electric resistance by improving the electrolysis efficiency. The optimum conditions were obtained by half round bus bar and Taguchi method. As the main control factors in the electropolishing process, current density, polishing time, electrolyte temperature and flow rate were selected. The electrolyte temperature was the most significant to the electrolysis efficiency. The optimum conditions for the life extension of electropolishing solution were as follows: current density, $45A/dm^2$; polishing time, 6 min; electrolyte temperature, $70^{\circ}C$; flow rate, 11 L/min. As a results of ANOVA of SN ratios, it was found that the electrolyte temperature was significant factor at the 90% confidence level.