• Nuclear Engineering and Technology
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• v.49 no.7
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• pp.1457-1462
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• 2017

Unsteady thermal processes in storage containers with spent nuclear fuel were modeled. The daily fluctuations of outer ambient temperatures were taken into account. The modeling approach, which is based on the solving of conjugate and inverse heat transfer problems, was verified by comparison of measured and calculated temperatures in outer channels. The time delays in the reaching of maximal temperatures for each spent fuel assembly were calculated. Results of numerical investigations show that daily fluctuation of outer temperatures does not have a large influence on the maximal temperatures of stored spent fuel, so that fluctuation can be neglected and only daily average temperature should be considered for safety estimation using the "best estimation" approach.

• Journal of Korean Institute of Industrial Engineers
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• v.23 no.4
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• pp.719-728
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• 1997

In the AGV routing a vehicle can select the shortest route on which no conflicts are anticipated. The procedure includes time constraint and the node/arc occupation times of vehicles in order to locate the conflicting paths. The slight differences among AGV routing algorithms exist in identifying the conflict regions encountered while reaching out to the destination node. In this paper, a novel approach to the use of the re-routing scheme is presented. It will be used to minimize the travel distance of vehicles in a regular vehicle routing process rather than to cope with emergency situations. The proposed algorithm provides existing active vehicles with the ability of changing their current paths for a new vehicle whenever the equal-distance paths exist, in on attempt to optimize the AGV transportation system. This ability is possible because of the flexibility of on AGV system controlled by a computer system.

• The Journal of Korean Physical Therapy
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• v.10 no.1
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• pp.149-154
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• 1998

This study was designed 1) to quantitatively observe changes in static platform and 2) to observe balance performance using vision. Seventy-five subjects participated in the study. Subjects comprised 39 males and 36 females(mean ages=23.8 years) without neurologic and orthopaedic impairments. Static balance was measured with eyes open and closed. Subjects was required to move the cneter of balance curser in a counterclockwise for 30 sec. The effect for the COBx(-) suggests that subjects tended to maintain their weight slightly In the left. The time taken and the accuracy to move the center of balance from target to target was 14 sec, $49.47\%$. The body sway upon reaching the target was 7.3 AP sway and 11.88 LR sway distance. In this study, the data developed could be appropriate to use for sine comparisons when balance training patients with neurologic or orthopaedic impairments.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.06a
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• pp.449-452
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• 1998

In this paper, we implemented the variable fuzzy speed controller of an IM(induction motor) using the fuzzy control algorithms. Specially, we proposed a self-tuning technique of scale factors which could make easily the fuzzy speed controller optimize. Comparing with the conventional PI speed controller, the dynamic performances of a proposed fuzzy controller such as the reaching time, the maximum overshoot and the robustness against load disturbance were substantially improved.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1996.10b
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• pp.193-205
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• 1996

This paper deals with experimental study on thermal characteristics that a cooling fluid is affected to ice ball as being measuring the temperature in storage tank and ice ball governing the rate of heat storage. Distributor was taken as inlet geometry factor. flow rate of cooling fluid which was a brine were 2, 4, and 6LPM, and 8, 10, and 12$^{\circ}C$ in the temperature difference for dynamic factors with respect to three ice ball types(103, 96, 76mm). In case of in flowing cooling fluid, since inertia force is suppressed by lower flow rate the amount of heat was transferred to ice ball by heat conduction high because density difference is high. And in case of larger ice ball, a long-term storage was available because reaching time at steady state is relatively long. consequently, smaller ice ball could be suitable to a short-term storage.

• Journal of IKEEE
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• v.15 no.2
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• pp.149-156
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• 2011

In this paper, a new discrete variable structure controller based on a new sliding surface and discrete version of the disturbance observer is suggested for the control of uncertain linear systems. The reaching phase is completely removed by introducing a new proposed sliding surface. The discrete version of the disturbance observer is derived for the effective compensation of the effect of uncertainties and disturbances. A corresponding control input with the disturbance compensation is selected to guarantee the quasi sliding mode on the predetermined sliding surface for guaranteeing the designed output in the sliding surface from any initial condition to the origin for all the parameter variations and disturbances. By using Lyapunov function, the closed loop stability and the existence condition of the quasi sliding mode is proved. Finally, an illustrative example is presented to show the effectiveness of the algorithm.

• Journal of Pharmaceutical Investigation
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• v.18 no.2
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• pp.49-53
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• 1988

Pivaloyloxymethyl ester of piperacillin was synthesized by reacting sodium piperacillin with chloromethyl pivalate, and its chemical structure was determined by infrared and $^1H$ nuclear magnetic resonance spectroscopic methods. The pharmaceutical properties of the ester were investigated to assess its potential as a novel prodrug of piperacillin. The interface transfer of piperacillin and the ester was studied in a two-phase in vitro system composed of aqueous pH buffers and n-octanol. The ester was more lipophilic, and less water soluble above pH 4.0 than piperacillin. Significant antibacterial activity was not observed in the ester in vitro, but the ester was hydrolyzed into the parent drug in the rat liver homogenate. The serum levels of orally administered ester suspension containing 0.1% Tween 80 were measured in rabbits. It was found that the ester showed higher blood level, comparing with no observation of piperacillin in serum, but the time reaching the maximum serum concentration was 5 hr.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.815-820
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• 2001

This study is to set a new standard for using of the colorimetric method through grasping the character of the colorimetric method, and measuring the chloride concentration at the place of the change of color. Also, to predict chloride concentration around rebar and time reaching limit chloride concentration through measuring the chloride concentration of concrete surface by the colorimetric method and this study presents the new program of concrete degradation and diagnosis of the durability by salt damage. First the use of the colorimetric method was examinated, second the chloride concentration through slicing concrete submerged in artificial seawater for 6 months was measured. And the chloride concentration at the place of the change of color was calculated by using colorimetric method. Finally, the cloride concentration of the concrete surface was calculated.

• Environmental Engineering Research
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• v.10 no.4
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• pp.199-204
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• 2005

Experiments were performed to estimate the organic release from the aquifer soil in riverbank and/or riverbed filtration via a kinetic approach. Organic release was assumed as a reaction of first order regarding concentrations in both soil and water phases. The reaction rate constants were obtained by comparing the model predictions with the experimental data of organic release reaction and the equilibrium distribution of organic matter between water and soil phases. Results show that the organic release from the aquifer soil was not negligible under normal conditions in Korea reaching 4.7mg-COD/L-day. This indicates that manganese and iron start to be released from aquifer soil in the riverbank filtration in the middle reach of the Nakdong river if the travel time of the filtrate exceeds about 5 days. It was also seen that the COD of the soil organic matter was 0.89mg-COD/mg-OM and that 65% of the COD was BOD5.

• Journal of the korean Society of Automotive Engineers
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• v.14 no.3
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• pp.80-89
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• 1992

An experimental study of in-cylinder of flow and combustion characteristics in two gasoline engines of different intake ports which are denoted as original port and masked shroud head (MSH) ports is presented. The flows generated by the MSH and the original port are invest- igated by laser Doppler velocimeter(LDV) under steady flow and motoring (non-firing) condit -ions. Combustion characteristics with different swirl levels produced by two intake ports are analyzed by combustion pressure measurement and statistical calculation. The swirl inside the cylinder of the MSH port engine is found to be much higher than the original port, and the MSH has a large eddy motion of cylinder diameter size. Using ensemble average method to valuate engine turbulence under motoring condition, the MSH port engine is shown to have h -igher turbulence intensity than the original port, so that the effect of the MSH port on fast burn is shown. Also the cyclic variations of peak pressure and the reaching time in the MSH port are apparently reduced.