• Proceedings of the KSME Conference
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.286-291
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• 2001

This paper describes an optimal scheduling for ice slurry systems for energy cost saving. The optimization technique applied in the study is the dynamic programming method, for which the state variable is the storage in the ice storage tank and the control variable is the state of chiller's on-off switching. Though the costs during charge period is included in optimization by taking the average cost of ice per hour for slurry making, the time horizon for the simulation is limited building cooling period because accurate charge rate from the ice maker into the ice storage tank cannot be estimated during the charge period. In the operating simulation after optimizing procedure, energy consumption and operating cost for the optimal control are calculated and compared with them for a conventional control with one case of cooling load profile.

• Journal of the Korean Society of Food Science and Nutrition
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• 제23권4호
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• pp.618-624
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• 1994

The addition of mustard leaf to kimchi making for extanding the optimum edible period was studied. The quality and sensory characteristics of mustard leaf added kimchi were evaluated . The activity, lactic and acetic acid contents of mustard leaf added kimchi showed lower than that of control kimchi but reducing sugar and vitamin C contents was higher. The duration of optimum edible periods of mustard leaf added kimchi lasted one more weak. While the optimum pH of kimchi for eating lasted, the sensory pannel score for sour taste of mustard leaf added kimchi was lower than that of control but the scoreas for savory taste, carbonated taste and hardness were higher . Especially , the sour taste score between two groups were significantly different (p<0.05). Overall quality score for the mustard leaf added kimchi was higher. There was no differences in texture determined by Penetrometer between mustard leaf added kimchi and control kimchi until the fermentation reached the optimal condition for eating . After that period , the degree of degradation of texture was much delayed in mustard leaf added kimchi.

• Industrial Engineering and Management Systems
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• 제15권2호
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• pp.123-130
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• 2016

We introduce a queueing system with general arrival stream and exponential service time under the N-policy, where customers may renege during idle period and arrival rates may vary according to the server's status. Probability distributions of the lengths of idle period and busy period are derived using absorbing Markov chain approach and a method to obtain the optimal control policy that minimizes long-run expected operating cost per unit time is provided. Numerical analysis is done to illustrate and characterize the method.

• Asian-Australasian Journal of Animal Sciences
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• 제14권12호
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• pp.1712-1718
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• 2001

An experiment was carried out to study the effect of monensin administration on mammary functions in crossbred Holstein cattle. Fourteen non-pregnant late lactating crossbred Holstein cattle, approximately 270 days postpartum, were selected for the experiment. They were divided into two groups of 7 animals each. Seven animals in the treated group were given sodium monensin orally in a slow-release capsule. Animals in both control and treated groups were fed the similar diet to maintain milk production and body score at 2.5. Rice straw was fed as a source of dietary fiber throughout the experimental period. After monensin administration, a significant increase in the molar percent of ruminal propionate (p<0.05) and a significant decrease in the molar percent of ruminal acetate (p<0.05) were apparent in comparison to the pretreated period. The ratio of acetate to propionate concentration decreased significantly after monensin administration (p<0.05), while it was maintained at the similar level throughout the period of experiment in the control group. Monensin did not affect the molar percent of ruminal butyrate and valerate. The concentration of milk allantoin between the control group and monensin treated group was not different. An excretion rate of allantoin in milk decreased in animals treated with monensin (p<0.05). Mammary blood flow did not show significant difference between control and monensin treated groups. The plasma glucose concentration, arteriovenous concentration difference and mammary gland uptake of glucose remained constant in both groups. Milk yield of the later stage of lactation in the control group declined during lactation advance while a tendency to increase in the milk yield was apparent after 21 days monensin administration. Milk compositions for concentration of lactose, fat and protein in both control group and monensin treated group did not change throughout the experimental periods. From these results, it can be concluded that the action of monensin could affect the ruminal fermentation pattern. Monensin could not increase milk yield in the late lactating period.

• Asian-Australasian Journal of Animal Sciences
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• 제12권3호
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• pp.354-357
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• 1999

Hypothyroidism was induced in three age groups (8 months, 1 year and 2 years) of Black Bengal goats by administering thiourea subcutaneously for 30 days. From fourth day onwards the animals were observed to be in hypothyroid state. For 8 months age group, a control group of similar age was taken. For the 1 year and 2 years age groups there was no control group but the values obtained on the pre-treatment day were considered as control values. For confirming the establishment of hypothyroidism, peripheral plasma triiodothyronine $(T_3)$ and thyroxine $(T_4)$ were estimated in all the animals before and during the treatment period by radioimunoassay. In the thiourea treated 8 months age group the $T_3$ and $T_4$ levels were significantly (p<0.001) lower than those in the control group during the treatment period. In all the thiourea treated groups the $T_3$ and $T_4$ levels observed during the treatment period were significantly (p<0.01) lower than the pre-treatment levels. A nonsignificant loss in the body weight was observed in all the thiourea treated groups whereas there was a significant growth in the control group of animals. The study indicates that hypothyroidism has a negative effect on growth in goats.

• Journal of the Korea institute for structural maintenance and inspection
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• 제7권2호
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• pp.135-140
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• 2003

As a construction technique is developed recently, the construction space and construction period are considered to important matters. Especially, in case of construction period, several method is proposed for strength control in the construction field. However there are very little strength control models for application of internal condition. The purpose of this study is to develop a strength control model for application of variety internal condition at construction field. The results are as follows ; 1) According to the results of compressive strength of concrete evaluated by logistic curve and proposed curve, proposed curve is applicable of construction field because there is similar relation with logistic curve. 2) It is shown that the construction period is shortened by reduction of the formwork removal time, because a predicted compressive strength of using the new curve is higher than the proposed compressive strength of standard.

• Korean Journal of Health Education and Promotion
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• 제24권2호
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• pp.93-109
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• 2007

Objectives: The purpose of the study was to examine the effects of experience based menstrual education program on menstrual attitude and menstrual discomfort among female elementary students. Methods: Non-equivalent control group, pre-post test design was utilized for the study. The participants in the study were 122 female elementary students in P city. They were assigned into 2 groups: The experimental group of 62 and the control group of 60. The experience based education program consisted of 5 sessions with 40 minute length. For control group, no treatment was provided during the period. Post-tests were conducted just after the following menstrual period for both experimental and control groups. The data was analyzed using SPSS WIN 12.0 program. The t-tests were used to answer the research questions. Results: There were significant differences in menstrual attitude and menstrual discomfort between experimental and control groups, The students who participated in the program reported more positive attitude to the menstruation and less discomfort during menstrual period than the students who did not participate in the program. Conclusions: Experience based education had a positive influence on menstrual attitude and menstrual discomfort among female elementary students. Further application of the program would be beneficial for the female elementary students. Future research to standardize the program to the broader population is warranted.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• 제27권8호
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• pp.432-439
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• 2015

Current building procedures seek to minimize external air supplies to reduce the energy consumption of air conditioning, resulting in a high dependency on mechanical ventilation. We therefore studied an economizer-cycle system, whereby the introduction of external air saves energy. We analyzed different economizer-control methods, addressing mixed-air temperatures and outdoor-air fractions according to outdoor-air temperatures; also, we analyzed the energy consumption of the three economizer-cycle control types using detailed EnergyPlus simulation modeling. A differential enthalpy control method showed a lower energy consumption range from 5.8% to 6.2% than that of other methods during the simulated period. A differential dry-bulb control method showed a 12.7% lower energy consumption than the no-economizer method in the intermediate period, but also showed 7.1% more energy consumption during the summer period. When latent heat was not removed due to high summer humidity, we found a significant level of resultant energy consumption.

• Journal of The Korean Society of Agricultural Engineers
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• 제55권4호
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• pp.83-93
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• 2013

Annual average precipitation of Korea is 1,277 mm and around 2/3 of annual precipitation and 74 % of available water resources occurred during monsoon period. In recent years, many agricultural reservoirs have been heightened to increase flood control capacity, reduce flooding damage at downstream areas, and provide sustainable environmental flow during drought period. Thus in this study, the flood control effects of heightening of reservoir banks were simulated with HEC-ResSim and HEC-RAS models. These modes were applied to Bonghak reservoir and it was found that flood control effects were 3~4.5 % with 7 -m heightening. Also, with proper operation (1 m lower of full water level) of reservoir right before the monsoon period, flooding at downstream could be prevented even with design storm of 80 -year recurrence interval. As shown in this study, heightening of agricultural reservoir provides positive effects in flood control and flood damage reduction.

• International Journal of Precision Engineering and Manufacturing
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• 제6권3호
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• pp.37-44
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• 2005

Gait control capacity for most trans-femoral prostheses is significantly different from that of a normal person, and training is required for a long period of time in order for a patient to walk properly. People become easily tired when wearing a prosthesis or orthosis for a long period typically because the gait angle cannot be smoothly adjusted during wearing. Therefore, to improve the gait control problems of a trans-femoral prosthesis, the proper gait angle is estimated through surface EMG(electromyogram) signals on a normal leg, then the gait posture which the trans-femoral prosthesis should take is calculated in the neural network, which learns the gait kinetics on the basis of the normal leg's gait angle. Based on this predicted angle, a postural control method is proposed and tested adaptively following the patient's gait habit based on the predicted angle. In this study, the gait angle prediction showed accuracy of over $97\%$, and the posture control capacity of over $90\%$.