• Journal of the Korean Operations Research and Management Science Society
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• v.31 no.3
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• pp.81-96
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• 2006

We consider a rental company that dynamically manages Its capacity level through capacity addition and return While serving customer with its own capacity, the company expands its capacity by renting items from an outside source so that it can avoid lost opportunities of rental which occur when stock is not sufficient. If stock becomes sufficiently large enough to cope with demands, the company returns expanded capacity to the outside source. Formulating the model into a Markov decision problem, we identify an optimal capacity management Policy which states when the company should expand its capacity and when it should return expanded capacity after capacity addition. Since it is intractable to analytically find the optimal capacity management policy and the optimal size of capacity expansion, we present a numerical procedure that finds these optimal values based on the value iteration method. Numerical analysis is implemented and we observe monotonic properties of the optimal performance measures by system parameters, which are meaningful in developing effective heuristic policies.

• Journal of the Korean Society for Railway
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• v.3 no.4
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• pp.213-218
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• 2000

Waste landfill is so loose that it may cause the insufficient bearing capacity and the differential settlement. And so, characteristics and conditions of the ground should be considered in applications of ground improvement in waste landfill. In this paper, analysis of field tests as the static loading test and the bearing capacity test were performed. In result, PG(Pack Grouting) pile method is proved effective and economic, because it could bring about the increase of end bearing capacity, the prevention of differential settlement and increase of density by expansion of pile.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.8 no.2
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• pp.208-218
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• 1996

Performance of a VM heat pump is considerably affected by various losses, such as enthalpy dump, reheat loss, pumping loss, conduction loss and shuttle loss. A second-order analysis model of VM heat pumps, which allows consideration of the major losses, was presented. Actual heat transfer rates for heat exchangers were calculated from the heat transfer rates obtained by the adiabatic analysis and various losses. New effective temperatures of heat exchangers were calculated from the actual heat transfer rates and the mean heat transfer coefficients until there was no appreciable change in the effective temperatures. Effects of design parameters, such as phase angle, swept volume ratio, regenerator length and speed on heating capacity, cooling capacity and COP were shown.

• Journal of Korean Institute of Industrial Engineers
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• v.32 no.2
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• pp.104-110
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• 2006

When a new facility such as automobile assembly line is designed, computer simulation is often used to estimate its actual throughput level. If it falls short of the target throughput level, then the design must be modified to increase the throughput capacity. For complex facilities having parallel processes and network of material flows, the modification procedure is not trivial. Even if the capacity of a particular bottleneck process is increased, the target throughput may not be achieved because the bottleneck may move to another process. Furthermore, each process has a different set of options with different cost to increase the capacity. In this study, we present a systematic procedure of determining the cost-effective set of options which achieves the target throughput.

• The Journal of Korean Physical Therapy
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• v.32 no.2
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• pp.121-125
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• 2020

Purpose: The purpose of this study was to evaluate the forced vital capacity and sway area of respiratory muscles taping with threshold inspiratory muscles training for 1 week. Methods: Nineteen stroke patients were divided into two groups: experimental group (respiratory muscles taping with threshold inspiratory muscles training, n=10) and control group (threshold inspiratory muscles training, n=9). Forced vital capacity tests were performed using a spirometer. The instrument records the forced vital capacity (FVC). COP excursion test was performed using Zebris. The instrument records the sway area. All tests were measured before and after intervention. Results: The experimental group and control group showed significant increase in FVC (p<0.05). The sway area showed a significant decrease only in the experimental group (p<0.05). The FVC and sway area was no significant difference between the two groups (p>0.05). Conclusion: Threshold inspiratory muscles training is an effective intervention for improving FVC. Threshold inspiratory muscles training with respiratory taping is an effective intervention for improving FVC and sway area. Threshold inspiratory muscles training with respiratory taping can improve balance ability.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.4
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• pp.480-486
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• 2005

The main goals of this work are to investigate the effect of molecular weight distribution(MWD) and activated carbon adsorption capacity after conventional coagulation and enhanced coagulation. The ozonation was very effective to decompose the NOM to smaller size and to remove molecular smaller than 1,000. The concentration of DOC was reduced 0.25mg/L and 0.56mg/L by the conventional coagulation and the enhanced coagulation, respectively The conventional coagulation was not effective to remove NOM. However, the enhanced coagulation was effective to remove MW bigger than 10,000. The higher MW was shifted to smaller weight by ozonation in the raw water and the after conventional coagulation. After enhanced coagulation the MW had not changed significantly by ozonation. Also, it was observed that the ozone dosage did not have significant impact on MW shifting to smaller size. The adsorption capacity simulated by IAST comparing K values showed that the adsorption capacity was not impacted by ozone doses. There was very strong correlation between MW smaller than 10,000 and the mid- and strongly adsorbable fractions.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.3
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• pp.297-304
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• 2014

The purpose of this study is to evaluate the experimental performance characteristics of a water-to-water geothermal heat pump featuring a vapor refrigerant injection for the production of hot water. The performance of geothermal heat pump with a vapor injection was evaluated by comparing with that of a conventional geothermal heat pump without a vapor injection. For heating operation, the geothermal heat pump with a vapor injection is superior in COP and heating capacity. The vapor injection was more effective for supplying hot water while overloading. The vapor injection was effective for the improvement of the cooling capacity. However, the vapor injection was not effective for the increasing of COP according to the increased input of a compressor. The advantage of vapor injection in water-to-water geothermal heat pump become disappeared while cooling operation with lower part loading.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.4
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• pp.123-132
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• 2008

Aseries of in-situ tests and ground water level measurements with stone and slug materials had been conducted to find out effect of ground settlement reduction and bearing capacity improvement by the Stone Column method. As the result of the tests, it was proved that the Stone Column method is effective for reduction of ground settlement and improvement of bearing capacity. In addition the ground water level went down without overburden load. These results show that the Stone Column method is effective for an increase in density and resistance to liquefaction. The results of estimation of ground settlement and bearing capacity by general theoretical equation, it show that the Stone Column method increases bearing capacity by 2.7~5.7 times and decreases ground settlement by 2~3.5 times.

• Journal of Information Technology Applications and Management
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• v.18 no.1
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• pp.101-123
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• 2011

Considering how an organization is timely competitive for survival in the rapidly changing environment of today, it is more important to get new information and knowledge continuously by teams. However team system provides organization with opportunities and, at the same time, is provoked into conflict by the diversity of team members. This study examines the effect of team diversity on knowledge creation and investigates the influence of absorptive capacity and conflict as mediators. The sample population consisted of officials who work in teams at two business corporations that have successfully achieved knowledge creation. The result presents team diversity serves as an effective factor for absorptive capacity and absorptive capacity also serves as an effective factor for knowledge creation. In contrast, team diversity brings team members into conflict and conflict has a negative effect on knowledge creation. Another significant finding of this research is the fact that a positive effect of absorptive capacity on knowledge creation is greater than a negative effect of conflict on it. It clearly demonstrates that team diversity can be an important determinant of knowledge creation if an organization tries to reduce team member's conflict.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.733-741
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• 2018

Capacity estimation is indispensable to ensure the safety and reliability of lithium-ion batteries in electric vehicles (EVs). Therefore it's quite necessary to develop an effective on-board capacity estimation technique. Based on experiment, it's found constant current charge time (CCCT) and the capacity have a strong linear correlation when the capacity is more than 80% of its rated value, during which the battery is considered healthy. Thus this paper employs CCCT as the health indicator for on-board capacity estimation by means of relevance vector machine (RVM). As the ambient temperature (AT) dramatically influences the capacity fading, it is added to RVM input to improve the estimation accuracy. The estimations are compared with that via back-propagation neural network (BPNN). The experiments demonstrate that CCCT with AT is highly qualified for on-board capacity estimation of lithium-ion batteries via RVM as the results are more precise and reliable than that calculated by BPNN.