• 설비공학논문집
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• 제15권5호
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• pp.372-381
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• 2003

This study aims to find out the optimized insulation thickness of refrigerated warehouse with different envelope structures (RC and PC wall) and insulation materials (urethane and icynene). Each of them is compared according to the thickness of insulation (100, 150, 200 mm/50 or 250 mm) and the temperature of cold storage room (0, -6, -15$^{\circ}C$). As results, it is proved to have the best economical efficiency in life cycle cost when PC wall with thickness of 100 mm (0 and -6$^{\circ}C$) and 150 m (-15$^{\circ}C$) urethane, respectively, are applied.

• 전기학회논문지
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• 제57권12호
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• pp.2322-2329
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• 2008

In this study, we introduce the design methodology of an optimized fuzzy cascade controller with the aid of particle swarm optimization(PSO) for ball & beam system. The ball & beam system consists of servo motor, beam and ball, and remains mutually connected in line in itself. The ball & beam system determines the position of ball through the control of a servo motor. We introduce the fuzzy cascade controller scheme which consists of the outer(1st) controller and the inner(2nd) controller as two cascaded fuzzy controllers, and auto-tune the control parameters(scaling facrors) of each fuzzy controller using PSO. For a detailed comparative analysis from the viewpoint of the performance results and the design methodology, the proposed method for the ball & beam system which is realized by the fuzzy cascade controller based on PSO, is presented in comparison with the conventional PD cascade controller based on serial genetic alogritms.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 A
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• pp.118-120
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• 1999

This paper describes a new procedure to develop a systems model of a universal motor based on finite element analysis. The purpose of this paper optimized fabrication of Universal Motor for improving its efficiency and performance and driving range. To do this, various design parameters are set such as a number of teeth and stator shape, etc. As results, the optimized model has made good improvement compared with those of the initial.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 A
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• pp.247-249
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• 1998

This paper has proposed an optimized universal motor for improving its performance and cost using FEM program. To do this, various design parameters are set such as air gap length, shape of stator and pole shoe, rotor slot, rotor shaft diameter, etc. As results, the optimized model has made good improvement compared with those of the initial.

• 전자통신동향분석
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• 제33권2호
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• pp.39-47
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• 2018

The fundamental problem of communication is that of transmitting a message from a source to a destination over a channel through the use of a transmitter and receiver. To derive a theoretically optimal solution, the transmitter and receiver can be divided into several processing blocks, with each component analyzed and optimized. The idea of machine learning (or deep learning) communications systems goes back to the original definition of the communi-cation problem, and optimizes the transmitter and receiver jointly. Although today's systems have been optimized over the last decades, and it seems difficult to compete with their performance, deep learning based communication is attractive owing to its simplicity and the fact that it can learn to communicate over any type of channel without the need for mathematical modeling or analysis.

• International Journal of Aeronautical and Space Sciences
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• 제13권1호
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• pp.27-33
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• 2012

The relationship between the excitation frequency and the vortex shedding frequency is analyzed during the oscillation of the circular cylinder. Two-dimension unsteady Navier-Stoke's equation is calculated by using the Optimized High Order Compact (OHOC) scheme. The flow condition is Mach number 0.3 and Reynold's number 1000. From the results acquired by calculation, it can be inferred that, when the excitation frequency is near the vortex shedding frequency at the fixed cylinder wake, the oscillation frequency of lift and drag coefficients appears to lock-on. The lock-on refers to a phenomenon in which the aerodynamic coefficient appears as one primary oscillation frequency through excitation and its amplitude is amplified. In the non-lock-on zone, the excitation frequency is not in the lock-on mode anymore and beat is formed in which two or more primary oscillation frequencies of the aerodynamic coefficient are mixed together.

• 한국토양비료학회지
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• 제48권6호
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• pp.724-730
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• 2015

The aim of this study was to produce Aminotosan$^{(R)}$ fertilizer using optimized chitosan coagulant from waste livestock blood. Amino-acid fertilizer was produced by pretreated livestock blood. Chitosan coagulant was aggregated with amino-acid fertilizer to produce Aminotosan$^{(R)}$. Optimized coagulation conditions were set using chitosan coagulant such as 10% citric acid and 500 ppm chitosan coagulant by analysis of CST and TTF. The efficiency of coagulation by chitosan coagulant under the optimal conditions was better than chemical coagulants. After solid/liquid separation for coagulated amino-acid fertilizer, Aminotosan$^{(R)}$ fertilizer which added eco-friendly and aesthetic functions was produced.

• Current Optics and Photonics
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• 제3권3호
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• pp.236-242
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• 2019

An Nd:YAG slab structure was designed for a high-power zigzag slab laser amplifier based on computational simulation of the wavefront distortion. For the simulation, the temperature distribution in the slab was calculated at first by thermal analysis. Then, the optical path length (OPL) was obtained by a ray tracing method for the corresponding refractive index variation inside the slab. After that, the OPL distribution of the double-pass amplified beam was calculated by summing the results obtained for the first and second passes. The amount of wavefront distortion was finally obtained as the peak-to-valley value of the OPL distribution. As a result of this study, the length and position of the gain medium were optimized by minimizing the transverse wavefront distortion. Under the optimized conditions, the transverse wavefront distortion of the double-pass amplified beam was less than $0.2{\mu}m$ for pump power of 14 kW.

• 한국물환경학회지
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• 제27권5호
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• pp.617-624
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• 2011

In order to confirm the creation of the OH radical which influences to RNO bleaching processes, it experimented using laboratory reactor of dielectric barrier discharge plasma (DBDP). The experiments performed in about 4 kind process variables (diameter of ground electrode, diameter of discharge electrode, diameter of quartz tube and effect of air flow rate) which influence to process. In order to examine optimum conditions of design factors as shown in Box-Behnken experiment design, ANOVA analysis was conducted against four factors. The actual RNO removal at optimized conditions under real design constraints were obtained, confirming Box-Behnken results. Optimized conditions under real design constraints were obtained for the highest desirability at 1, 1 mm diameter of ground and discharge electrode, 6 mm diameter of quartz tube and 5.05 L/min air flow rate, respectively.

• ETRI Journal
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• 제44권2호
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• pp.313-326
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• 2022

This study presents a noble scheme for distributed and parallel simulations with optimized agent placement for simulation instances. The traditional parallel simulation has some limitations in that it does not provide sufficient performance even though using multiple resources. The main reason for this discrepancy is that supporting parallelism inevitably requires additional costs in addition to the base simulation cost. We present a comprehensive study of parallel simulation architectures, execution flows, and characteristics. Then, we identify critical challenges for optimizing large simulations for parallel instances. Based on our cost-benefit analysis, we propose a novel approach to overcome the performance constraints of agent-based parallel simulations. We also propose a solution for eliminating the synchronizing cost among local instances. Our method ensures balanced performance through optimal deployment of agents to local instances and an adaptive agent placement scheme according to the simulation load. Additionally, our empirical evaluation reveals that the proposed model achieves better performance than conventional methods under several conditions.