• Proceedings of the Korean Society of Computational and Applied Mathematics Conference
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• 2003.09a
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• pp.6-6
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• 2003

In this work we consider the mathematical formulation and numerical resolution of the linear feedback control problem for Boussinesq equations. The controlled Boussinesq equations is given by $$\frac{{\partial}u}{{\partial}t}-{\nu}{\Delta}u+(u{\cdot}{\nabla}u+{\nabla}p={\beta}{\theta}g+f+F\;\;in\;(0,\;T){\times}\;{\Omega}$$, $${\nabla}{\cdot}u=0\;\;in\;(0,\;T){\times}{\Omega}$$, $$u|_{{\partial}{\Omega}=0,\;u(0,x)=\;u_0(x)$$ $$\frac{{\partial}{\theta}}{{\partial}t}-k{\Delta}{\theta}+(u{\cdot}){\theta}={\tau}+T,\;\;in(0,\;T){\times}{\Omega}$$ $${\theta}|_{{\partial}{\Omega}=0,\;\;{\theta}(0,X)={\theta}_0(X)$$, where $\Omega$ is a bounded open set in $R^{n}$, n=2 or 3 with a $C^{\infty}$ boundary ${\partial}{\Omega}$. The control is achieved by means of a linear feedback law relating the body forces to the velocity and temperature field, i.e., $$f=-{\gamma}_1(u-U),\;\;{\tau}=-{\gamma}_2({\theta}-{\Theta}}$$ where (U,$\Theta$) are target velocity and temperature. We show that the unsteady solutions to Boussinesq equations are stabilizable by internal controllers with exponential decaying property. In order to compute (approximations to) solution, semi discrete-in-time and full space-time discrete approximations are also studied. We prove that the difference between the solution of the discrete problem and the target solution decay to zero exponentially for sufficiently small time step.

• Korean Journal of Animal Reproduction
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• v.15 no.2
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• pp.109-115
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• 1991

This experiment was conducted to find out the time to farrowing induction after PGF2$\alpha$ treatment, the rate of farrowing induction, the effect of kids born by the induced farrowing on birth weight and development with study on artificial control of parturition in Korean native goats. A total of 24 pluriparous goats were offered for this experiment. The animals were divided into 4 goats per treatment by administration time(142, 145 or 148 day of pregnancy) and dosage (5 or 7.5mg). The results obtained in this experiments were as follows : 1. The effect of synchronization of estrus was induced 23 goats(95.1%), 16 goats(66.6%) in the 1st treatment and 7 goats(28.5%) in the 2nd treatment PGF2$\alpha$ and exhibited estrus at a mean interval of 75$\pm$5 hours after PGF2$\alpha$ injection. 2. The time to farrowing induction after PGF2$\alpha$ treatment on day 145 or 148 was significantly(P<0.01) shorter than that of the 5mg treatment, but there was no significant difference(P>0.01). 3. Parturition was induced in all goats(100%) treated 5 or 7.5mg of PGF2$\alpha$ on day 148 and 7.5mg of PGF2$\alpha$ on day 145, but was induced 75% in treatment with 5mg of PGF2$\alpha$ on day 145 and 5 or 7.5mg of F2$\alpha$ on day 142. 4. The birth weight and development of kids induced farrowing was heaviest (P<0.01) on days 148 among treatment, but there was no significant difference in dosage.

• The Korean Journal of Nuclear Medicine Technology
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• v.22 no.1
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• pp.51-54
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• 2018

Purpose $^{18}F-THK5351$ is the newly developed PET probe for tau imaging in alzheimer's disease. The purpose of study was to establish the automated production of $^{18}F-THK5351$ on a commercial module. Materials and Methods Two different approaches were evaluated for the synthesis of $^{18}F-THK5351$. The first approach (method I) included the nucleophilic $^{18}F$-fluorination of the tosylate precursor, subsequently followed by pre-HPLC purification of crude reaction mixture with SPE cartridge. In the second approach (method II), the crude reaction mixture was directly introduced to a semi-preparative HPLC without SPE purification. The radiosynthesis of $^{18}F-THK5351$ was performed on a commercial GE $TRACERlab^{TM}$ $FX-_{FN}$ module. Quality control of $^{18}F-THK5351$ was carried out to meet the criteria guidelined in USP for PET radiopharmaceuticals. Results The overall radiochemical yield of method I was $23.8{\pm}1.9%$ (n=4) as the decay-corrected yield (end of synthesis, EOS) and the total synthesis time was $75{\pm}3min$. The radiochemical yield of method II was $31.9{\pm}6.7%$ (decay-corrected, n=10) and the total preparation time was $70{\pm}2min$. The radiochemical purity was>98%. Conclusion This study shows that method II provides higher radiochemical yield and shorter production time compared to the pre-SPE purification described in method I. The $^{18}F-THK5351$ synthesis by method II will be ideal for routine clinical application, considering short physical half-life of fluorine-18 ($t_{1/2}=110min$).

• Asian Journal of Turfgrass Science
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• v.24 no.2
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• pp.211-217
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• 2010

This study was conducted to investigate a proper method of ball mark repair by comparing the creeping bentgrass recovery speed on golf course green treated by various methods of ball mark repair. Nine general repairing methods were tested and compared; control (no repair, A type), two common methods of USGA (B type) and GCSAA (C type), three methods with fork shaped hand set performing at Korean golf courses (Ansung Benest, D; Sky72, E; Lakeside, F type), and three methods using the repair machine with 6, 8, or 14 teeth (G, H, I type, respectively). Three creeping bentgrass cultivar of 'Penncross', 'T-1', and 'CY-2' were tested in this field experiment. This test was carried out from September to November in 2009 at the nursery on the Seoul Lakeside Golf course. The average speed of turfgrass recovery after various ball mark repairing methods have been ranked as in the order of E, D, C, B, F, I, H, G, and A. The methods of hand practise showed more effective results than repair method using machines. The ball mark recovery speeds of 'Penncross' were in the order of E, D, B, C, F, I, H, and A. In the case of 'T1' and 'CY-2', similar orders were showed as D, E, B, F, C, H, I, A, G and the order of D, E, C, F, B, H, G, I, A, respectively. The ball mark recovery speed among creeping bentgrass cultivar resulted in the order of 'CY-2', 'Penncross', and 'T-1'. The most proper method of ball mark repair was repair method using a hand set tool especially the method of the Sky72 Golf course (E type). At the first, remove a damaged grass area with fork and tap. And then gather the side grasses into the center area with pulling the grasses with fork. After that, make harden and flat on the turf surface by pounding and rolling with the round wooden stick. The final Nstep, water the repaired grass surface. This ball mark repairing practise showed a most rapid and proper recovery method on creeping bentgrass green.

• Journal of Digital Convergence
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• v.10 no.10
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• pp.397-404
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• 2012

The purpose of this study is to investigate the change of hamstring muscle relaxation and craniosacral reciprocal movement by using S. O. T. (sacrooccipital technique) categoryⅠ block-intervention process. 26 subjects with heel tension were randomly divided into two groups (EXP=13 and CON=13). This study carried out the category I block-intervention process on the experimental group and the false block-intervention process on the control group. Then, this study measured the sit-and-reach and sacral reciprocal movement of subjects before and after the intervention. The result values before and after the intervention were analyzed through ANCOVA by using SPSS PC Program (Ver. 20.0). In both investigations, the degree of hamstring muscle relaxation and the change of sacral reciprocal movement, there were statistically significant differences between the experimental group and the control group as [F(1, 23)=7.73, p<0.5] and [F(1, 23)=7.07, p<.05] respectively. According to the results of this study, it is expected that S. O. T category I bllock-intervention technique will have positive effect on both hamstring muscle relaxation and craniosacral reciprocal movement.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.115-118
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• 1998

ATM(Asynchronous Transfer Mode)을 기반으로한 BSC(Base Station Controller)를 이용한 무선 이동통신망에서는 크게 MSC, BSC, BTS로 구성 되어진다. BSC는 MSC(Mobile Switch Center)와의 STM-1급 (155.52Mbps) 정합이 이루어지며, 여러 BTS(Base Transceiver Subsystem)와 T1(1.544Mbps)/E1(2.048Mbps)급 정합이 이루어져 호연결, 관리, 제어 및 MT(Mobile Terminal)의 soft-handoff를 담당한다. BSC내의 저속 가입자 I/F에서는 BTS와 BSC내의 ATM switch와의 정합을 수행하면서 VPI/VCI변환, BSC 내부 cell format으로 변환, 그리고 UPC(Usage Parameter Control)등이 이루어진다. 본 논문에서는 ATM switch를 이용한 BSC 내부의 저속 가입자 I/F의 구현에 관해서 살펴본다.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.4
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• pp.121-128
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• 1998

In this study, when tension and bending stress act on plate simultaneously, stress intensity factor is analyzed at crack tip with using BEM(Boundary Element Method). In this analysis, stress intensity factors(S.I.F) are defined for variable ligament, aspect and stress ratio($\sigma$T/$\sigma$B). Consequently, predicted that crack grow to depth direction at low aspect and ligament ratio in tension stress and to surface direction in bending stress. Tension and bending stress act on plate same time, effect of tension stress in the first stage and effect of bending stress in the after stage was to observed. The outbreak of secondary crack in backside is under the control of stress amplitude and predict that the point of outbreak is mear backside.

• Korean Journal of Animal Reproduction
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• v.25 no.2
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• pp.125-130
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• 2001

This study was performed to report a direct dose dependent stimulatory effect of the Flavonoid(F) on basal testosterone secretion and a dose dependent effect on LH induced testosterone production by Leydig cell of matured rats in vitro culture. F was obtained kom the Rhus vernicifua through aceton extraction and silica gel adsorption column chromatography. Leydig cells (1$\times$10$^{6}$ cells/well) from 12 weeks old rats were incubated with or without F(0, 20, 40, 80, 160 ng) or insulin-like growth factor-I(IGF-I) in the presence or absence of LH(10, 100ng). 1. The maximal stimulatory concentrations of testosterone in culture media were showed at 24hr of culture. but these testosterone level were decreased at 36 hr of culture. 2. Flavonoid(80ng) were significantly(P ＜ 0.05) increased testosterone production compared with control groups for 12 hr culture. 3. Testosterone secretion by Leydig cells stimulated with LH(10, 100ng) for 6 hr and 12hr culture compared with 3 hr culture. 4. LH 10 ng augmented testosterone were increased by addition of F 40 ng for 12 hr culture. 5. F(0 and 40 ng) also enhanced LH 10 ng stimulated testosterone for 3 hr Leydig cells culture. 6. Addition of IGF-I 100 ng to the culture medium for 6 hr were increased the concentration of testosterone by Leydig cells stimulated with 100 ng LH. These results indicate that Flavonoid has a direct stimulatory effect on basal testosterone secretion in rat Leydig cells, and also modulates LH mediated testosterone. Therefore, Flavonoid may act as a modulator on gonadal development or gonadal steroidogenesis in direct or indirect.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.350-350
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• 2000

Since the heat exchange system, such as the boiler of power plant, gas turbine, and radiator require a high rate heat efficiency and the efficiency of these systems is depended on the control methods. However, it is important f3r operator to understand control system of these systems. In order to properly apply control equipment to these process control systems, such as boiler, any other heat process, or process control system it is necessary to understand the basic aspects and operation principle of the process that relate control, interrelationships of the process characteristics, and the dynamics that are involved. Generally, PID controllers are used in these systems but it is difficult for engineer to understand the complex dynamics and the tuning method because of the coupling action and disturbance in the system loop. In this paper, we design an effective experimental system fur automatic control education and analyze its characteristics through experimental system and industrial plant control software to study how they can team automatic control system by experiments.

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.211-219
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• 2018

This paper designs a nonlinear PI-type controller for the robust control of a boost DC-DC converter using a particle swarm optimization (PSO) algorithm. Based on the common knowledge that the transient responses can be improved if the P and I gains increase when the transient error is big, a nonlinear PI-type control design method is developed. A design procedure to autotune the nonlinear P and I gains is given based on a PSO algorithm. The proposed nonlinear PI-type controller is implemented in real time on a Texas Instruments TMS320F28335 floating-point DSP. Simulation and experimental results are given to demonstrate the effectiveness and practicality of the proposed method.