• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.2
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• pp.118-125
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• 2022

With the aim to maximize the use of a given voltage source in the field of railway and electric vehicles, this study applies a technique for controlling the overmodulation region between the linear and the six-step regions. High linearity overmodulation techniques that do not use look-up table (LUT) to digital signal processor (DSP) using carrier based pulse width modulation (PWM) are proposed. Such technique requires the phase of the voltage vector at the point where the circular trajectory of the voltage command vector and hexagonal cross each other. Therefore, a method is proposed to obtain a phase of a voltage vector that is derived through an equation and applied to a carrier-based PWM. Validity of the proposed implementation method is confirmed through simulation and experiment.

• Journal of Advanced Information Technology and Convergence
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• v.9 no.1
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• pp.103-113
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• 2019

Motivation: Polymerized actin-based cytoskeletal structures are crucial in shape, dynamics, and resilience of a cell. For example, dynamical actin-containing ruffles are located at leading edges of cells and have a significant impact on cell motility. Other filamentous actin (F-actin) bundles, called stress fibers, are essential in cell attachment and detachment. For this reason, their mechanistic understanding provides crucial information to solve practical problems related to cell interactions with materials in tissue engineering. Detecting and counting actin-based structures in a cellular ensemble is a fundamental first step. In this research, we suggest a new method to characterize F-actin wrapping fibers from confocal fluorescence image stacks. As fluorescently labeled F-actin often envelope the fibers, we first propose to segment these fibers by diminishing an energy based on maximum flow and minimum cut algorithm. The actual actin is detected through the use of bilateral filtering followed by a thresholding step. Later, concave actin bundles are detected through a graph-based procedure that actually determines if the considered actin filament is enclosing the fiber.

• International Journal of Advanced Culture Technology
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• v.11 no.4
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• pp.169-176
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• 2023

This study aims to assess the current status of career education at C University and to gather foundational data for developing a step-by-step career education curriculum and an integrated roadmap for curriculum and extracurricular career education. This research involves a comparative analysis of C University's enrolled students and external university students through a survey using the [University Career Exploration Model]. Data collection took place over one month in October 2023, and statistical analysis was conducted using the SPSS Statistics 25.0 program. The survey results enabled a comparative analysis of the career exploration processes and levels between enrolled students at C University and external university students. The proportion of enrolled students at C University responding positively to the career exploration process and level was high. Through this study, a better understanding of the career exploration processes and levels of university students was achieved. It is deemed necessary to conduct systematic research for continuous, tailored integration of curriculum and extracurricular career education at the university level.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.03a
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• pp.323-330
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• 1999

Daylight collapse have been occurred by about 5.0m deep at ground surface and collapse of the crown head part of the tunnel have connected to the ground surface during first step of shotcrete work after blasting of upper half section of the tunnel driving at two-way double track tunnel face section on highway construction. This study is for a successful illustration case for the earth improvement method through applying such strengthening methods as cement milk grouting, S.G.R grouting,, steel pipe reinforced multi-step grouting etc. for the purpose of earth strengthening of loosened earth block occurred by tunnel collapse.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2383-2388
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• 2011

LSMs are installed under girders along the long track. In order to improve the efficiency of the LSM, long stator LSM should be divided into the specified length and the propulsion inverters should have the system topology to generate high voltage and current for LSMs. This paper presents a system topology with two-step inverter in order to generate high voltage in inverter. A LSM propulsion system is developed and implemented in Maltab/Simulink. A system model of the two-step Inverter is applied to developed model. This paper demonstrates through simulation, advantages of multi-step inverter. The conclusions can serve the design of LSM propulsion system.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2298-2303
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• 2003

In this paper, very simple methods based on the exponential analysis are presented by which transfer function models for processes can easily be obtained. These methods employ step responses or impulse responses of the processes. These can also give a more precise transfer function model compared to the well-known graphical methods. Transfer functions are determined based on Prony method, which is one of the oldest and the most representative methods in the exponential analysis. Here, the method is reformed and applied to obtain the so-called low-order transfer function with pure time delay from the data of the step response. The effectiveness of the proposed method is examined through several numerical examples and experiments of the 2-tank level control process.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2090-2092
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• 2003

Adaptive algorithms are widely used for various applications. One challenging application is an echo canceller in the long distance telephony network. This paper proposes the new variable step-size algorithm for adaptive lattice structure for echo cancellation. The new algorithm is using power of the output signal and the error signal to controlled the step of adaptation process. By this technique, the proposed algorithm is an excellent and effective in good stability. Performance comparison of the proposed algorithm and the other algorithm is made through simulation results.

• The Journal of the Acoustical Society of Korea
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• v.28 no.3E
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• pp.93-98
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• 2009

In this paper, we propose a new VSS-NLMS algorithm through a simple modification of the conventional NLMS algorithm, which leads to a low complexity algorithm with enhanced performance. The step size of the proposed algorithm becomes smaller as the error signal is getting orthogonal to the input vector. We also show that the proposed algorithm is an approximated normalized version of the KZ-algorithm and requires less computation than the KZ-algorithm. We carried out a performance comparison of the proposed algorithm with the conventional NLMS and other VSS algorithms using an adaptive channel equalization model. It is shown that the proposed algorithm presents good convergence characteristics under both stationary and non-stationary environments despites its low complexity.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.261-264
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• 2003

Semi-solid processing is now becoming of great interest for the production of various parts by pressure die casting. Many advantages are associated with this forming process at the condition that the forming operation is performed under appropriate conditions. The thixoforming process, which needs a suspension of a globular, non-dendritic solid phase in the liquid phase, is characterized by three major steps. The first step is casting of billets with a microstructure suited for thixoforming. The second step is reheating of slugs cut from these billets. The third step is injection of the semi-solid slugs into a die. In this paper, the horizontal reheating machine to obtain the optimal conditions suitable for semiu-solid die casting process was used and applied to extrusion material. It is estimated the possibility of application on semi-solid die casting with extrusion material through various results.

• Culinary science and hospitality research
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• v.6 no.3
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• pp.425-442
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• 2000

The main purpose of this study is to propose that Beverage sales should be step-up in Family Restaurant. To achieve the purpose of this study theoretical and empirical approaches were used. In review of theoretical background, basic concepts and characteristics of beverage were studied. For empirical study, three Family Restaurant in Korea was selected and analyzed the beverage sales which classified to Liquor, Beer Wine and Non-alcoholic beverage. Based on it, I suggest a plan of beverage sales step-up of Family Restaurant as follow. First, keep the appropriate valance of the whole item: non-alcohol and alcohol item. Second, develop the menu should be effect beverage sales. Third, through the promotion and event the restaurant should derive the customer to purchasing behavior. Fourth. server can accommodate and offer the information of food and beverage menu that can evoke the customer's attention.