• Journal of the military operations research society of Korea
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• v.25 no.1
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• pp.37-54
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• 1999

In this paper, we proposed a modeling method of continuous combat simulation by using VENSIM. VENSIM is a CASE tool for developing continuous simulation. It provides a simple and flexible way of building simulation models from causal loop or influence diagram. As a case model, we developed "a prototype model of battle"incorporating infantry, artillery, air defense weapon, aircraft, and guerrilla engagement.ngagement.

• KIEE International Transactions on Electrophysics and Applications
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• v.11C no.4
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• pp.107-112
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• 2001

Laser Thomson scattering measurements of electrom temperature and density in a neutral loop discharge (NLD) plasma were performed in order to reveal the electron behavior around the neutral loop (NL). The experimental results were examined by using a simulation model that included effects of a three dimensional electromagnetic field with spatial decay of the RF electric field, and the limitation of the spatial extent of the electron motion and collision effect. From the experiments and modeling of the electron behavior, it was found that NLD plasma posses the electron temeprature $T_{e}$ and density ne peaks around the NL is essential for the formation of plasma. Also, the optimum condition of plasma production could be simply estimated by the calculation of $U_{av}$ and $F_{0}$././.

• East Asian mathematical journal
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• v.36 no.3
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• pp.365-376
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• 2020

Nonalcoholic fatty liver is a type of fatty liver in which fat accumulates in the liver without alcohol. In the accumulation, Nrf1 and miR-378 genes play very important role, so called negative feedback loop, in which the two genes suppress the other's production. In other words, Nrf1 activates fatty acid oxidation which promotes fat consumption in the liver, while miR-378 deactivates fatty acid oxidation. Thus, both genes regulate nonalcoholic fatty liver. In this paper, the negative feedback loop of Nrf1 and miR-378 are expressed by a system of ordinary differential equations. And, bifurcation simulation shows the change in the amount of each gene with significant parameter range changes. Bifurcation simulation has also used to determine the thresholds for transit between disease and steady state.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.10
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• pp.1633-1638
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• 2016

Loop system arrangement in the primary distribution system has been increased for higher reliability of power supply to the customer. This paper presents a new fault calculation method for the loop structured unbalanced distribution feeders. Mathematical modeling method of the distribution system and superposition principal based fault calculation procedures are provided. In order to establish feasibility of the proposed method, various case studies have been performed using Matlab power system toolbox.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1327-1331
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• 1990

A new dual loop controller using color LCD bar graphs with LED back lights has been developed. An optional memory card is used to load or save the controller configuration, which may be a preprogrammed standard package or a user-programmed configuration, in addition to the built-in functions ready for user selection. The bar-graph display is selectable for single-loop or dual-loop use. A high grade of self-tuning functions using a modeling technique is built-in as standard. The controller can accommodate optional plug-in modules for thermocouples, communication, etc. All the options are fully field upgradable.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.3 no.1
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• pp.58-65
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• 2003

In this paper, a new model, which is a Takagi-Sugeno fuzzy model, for mobile robot is presented. A controller, consisting of two loops the one of which is the inner state feedback loop designed for stability and the outer loop is a PI controller designed for tracking the reference input, is suggested. Because the robot dynamics is nonlinear, it requires the controller to be insensitive to the nonlinear term. To achieve this objective, the model is developed by well known T-S fuzzy model. The design algorithm of inner state-feedback loop is regional pole-placement. In this paper, regions, for which poles of the inner state feedback loop are lie in, are formulated by LMI's. By solving these LMI's, we can obtain the state feedback gains for T-S fuzzy system. And this paper shows that the PI controller is equivalent to the state feedback and the cost function for reference tracking is equivalent to the LQ(linear quadratic) cost. By using these properties, it is also shown in this paper that the PI controller can be obtained by solving the LQ problem.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.3 s.246
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• pp.246-254
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• 2006

The present study shows the experimental and modeling results of the cooling system using nanofludic loop thermosyphon. the experimental results show that nanofluid is not effective for small scale cooling system. The heat transfer performance is not much improved with the current small scale loop system comparing with the convectional water based loop system. In this study, various effects of nanofluids such as the concentration, the md of particle, host fluid, and heat capacity and so on were investigated. With nanofluid as the working fluid, the flow instability was improved at a certain concentration.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.85-86
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• 2022

Traditionally, the facility inspection was visually conducted by the managers, and consequently the result can be subjective because of different perspective and experience of them. To solve this problem, the studies on this topic has tried to integrate the UAS. However, it is still concerned to use in practice due to the lack of analysis of the performance factors affecting the UAS-based facility condition inspection. Hence, the purpose of this study is to identify the critical factors as well as their correlations by modeling causal loop diagram (CLD). A total of 20 variables were derived in four categorized groups, and the relationships were analyzed. Further study will develop a system dynamics (SD) model to simulate various scenarios based on stock-flow diagram through the defined relationships in this study.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.10
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• pp.871-880
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• 2000

A twin-servo mechanism is used to increase the payload capacity and assembling speed of high precision motion control systems such as semiconductor chip mounters. In this paper, we focus on the modeling of the twin-servo system and propose its network representation. And also, we propose a robust synchronizing motion control algorithm to cancel out the skew motion of the twin-servo system caused by different dynamic characteristics of two driving systems and the vibration generated by high accelerating and decelerating motions. The proposed control algorithm consists of separate feedback motion control algorithms for each driving system and a skew motion compensation algorithm. A robust tracking controller based on internal-loop compensation is proposed as a separate motion controller and its disturbance attenuation property is shown. The skew motion compensation algorithm is also designed to maintain the synchronizing motion during high speed operation, and the stability of the whole closed loop system is proved based on passivity theory. Finally, experimental results are shown to illustrate control performance.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.7
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• pp.343-351
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• 2003

In this paper, interleaved boost converter is applied as a first-stage converter in switch mode power supply. The first-stage converter plays a role to improve power factor. Interleaved Boost Power Factor Corrector(IBPFC) can reduce input current ripple as a single voltage control loop only without inner current loop, because input current is divided each 50% by two switching devices. Each converter cell is also operated in discontinuous current mode and inductor current of each converter is discontinuous. Total input current which is composed by each converter cell is continuous current. Thus, IBPFC is able to improve input current ripple. IBPFC operating in discontinuous current mode can be classified as six modes from switching state and be carried out state space averaging small signal modeling. A control transfer function is obtained according to the modeling. Not only steady-state characteristics but also dynamic characteristics is considered. Single voltage control loop is also constructed by the control transfer function. From experimental result, improvement of power factor and input current ripple are verified.