• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.5
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• pp.403-410
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• 2007

In this study, natural refrigerants and their mixtures that can supplement and replace R12 and R134a in automobile air-conditioners are studied. R134a is currently used as the refrigerant in new motor vehicle air conditioners, replacing the ozone depleting refrigerant R12. Although R134a has no ozone depletion potential, it has a relatively large global warming potential, approximately 1300 times that of $CO_2$ over a 100 year time horizon. For this reason, performance of natural refrigerants and their mixtures containing R152a, RE170 (Dimethylether, DME) and R600a (Isobutane) are measured under 2 different temperature conditions. They were tested in a refrigerating bench tester with an open type compressor. The test bench provided about 4 kW capacity and water and water/glycol mixture were employed as the secondary heat transfer fluids. Test results show that the coefficient of performance (COP) of these refrigerants is up to 21.55% higher than that of R12 in all temperature conditions. Overall, these fluids provide good performance with reasonable energy savings without any environmental problem and thus can be used as long term alternatives for automobile air-conditioners.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.10
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• pp.761-767
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• 2006

In this study, performance of 2 pure hydrocarbons R290 and R1270 was measured in an attempt to substitute R22 under 3 different temperature conditions. They were tested in a refrigerating bench tester with a hermetic rotary compressor. The test bench provided about 3.5 kW capacity and water and water/glycol mixture were employed as the secondary heat transfer fluids. All tests were conducted under the same external conditions resulting in the average saturation temperatures of $7/45^{\circ}C$ and $-7/41^{\circ}C$ and $-21/28^{\circ}C$ in the evaporator and condenser, respectively. Test results show that the coefficient of performance (COP) of these refrigerants is up to 11.54% higher than that of R22 in all temperature conditions. Compressor discharge temperatures were reduced by $14{\sim}31^{\circ}C$ with these fluids. There was no problem with mineral oil since the mixtures were mainly composed of hydrocarbons. The amount of charge was reduced up to 58% as compared to R22. Overall, these fluids provide good performance with reasonable energy savings without any environmental problem and thus can be used as long term alternatives for residential air-conditioning and heat pumping application.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.58-63
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• 2006

In this study, performance of 2 pure hydrocarbons and 3 mixtures was measured in an attempt to substitute R22 under 3 different temperature conditions. The mixtures were composed of R1270(propylene), R290(propane) and R152a. They were tested in a refrigerating bench tester with a hermetic rotary compressor The test bench provided about 3.5 kW capacity and water and water/glycol mixture were employed as the secondary heat transfer fluids. All tests were conducted under the same external conditions resulting in the average saturation temperatures of $7^{\circ}C/45^{\circ}C$ and $-7^{\circ}C/41^{\circ}C$ and $-21^{\circ}C/28^{\circ}C$ in the evaporator and condenser, respectively. Test results show that the coefficient of performance (COP) of these refrigerants is up to 11.54% higher than that of R22 in all temperature conditions. Compressor discharge temperatures were reduced by $14{\sim}31^{\circ}C$ with these fluids. There was no problem with mineral oil since the mixtures were mainly composed of hydrocarbons. The amount of charge was reduced up to 58% as compared to R22. Overall, these fluids provide good performance with reasonable energy savings without any environmental problem and thus can be used as long term alternatives for residential air-conditioning and heat pumping application.

• Journal of Arbitration Studies
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• v.32 no.1
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• pp.71-91
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• 2022

The legal integration in the European Union that seeks a unified system in consumer disputes and the German Consumer Dispute Mediation Act based on this pursues the procedural fairness of consumer disputes and the equality of results. The role and legal status of the dispute mediator, who plays a very important role in this process, and the stable operation of the dispute resolution system and the guarantee of reasonable results through the guarantee of fairness and independence are very important values. In particular, the dispute mediator under the Act is conceptually different from the existing mediator or mediator, and through this distinction, the duties and contents of the dispute mediator are also distinguished. For this reason, the qualifications of dispute mediators that affect the outcome of dispute mediation are strictly stipulated. There have been some criticisms of this strictness, and such strictness is also seen as an excessive limitation. However, these standards can be understood as one of the efforts to make the dispute mediation procedure more systematic and to operate objectively in accordance with laws and procedures. In addition, in relation to the issue of independence and impartiality of the dispute mediator, the status of the dispute mediator is guaranteed in various aspects. In economic terms, it is not influenced by external factors, and furthermore, in order to guarantee job stability, the results of job security and dispute resolution are not linked. By examining the appropriate level of discipline for these dispute mediators, we expect the developmental growth of the consumer dispute resolution system under our Act.

• Journal of the Korea Institute of Building Construction
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• v.10 no.4
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• pp.49-57
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• 2010

Selecting an appropriate formwork to fit the construction of a high-rise building is an important factor that can influence the success or failure of a construction. Currently, however, the reality is that in domestic high-rise building construction, the selection of an appropriate formwork with consideration of the characteristics of the formwork has not been done in a reasonable manner. To select formwork in a systematic and reasonable fashion, comprehensive consideration is required that must not only include the aspect of construction costs, but also air, quality, safety, and environmental issues. Therefore, this study aims to rationalize the selection process of formwork by applying the scientific method of Analytic Hierarchy Process (AHP) to the selection process of formwork, in terms of construction costs, quality and safety. To do this, the researcher investigated the current status of formwork being used in high-rise residential building construction. Then, based on the results of this investigation, the researcher selected an alternative for the formwork, and taking construction experts as the subjects of this study, conducted a survey on the applicability of the formwork as well as the priority of management thereof when selecting formwork. It is judged that the results of this research will contribute a more scientific and reasonable decision-making process than the existing non-scientific method in selecting formwork for high-rise residential building construction.

• Journal of Navigation and Port Research
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• v.27 no.3
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• pp.335-343
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• 2003

Currently serious conflicts of interests are arisen for the use of coastal area in Korea. However, there no mediation program, mediators' consistent policies and reasonable laws to resolve conflict of interests which may be arisen when developing coastal area. The objective of this study is to lay the evaluation criteria for the formalized objective evaluation among disputants of coastal conflicts for the better understanding and characterizing of coastal conflicts in Korea. In order to do so, this study has adopted for the extraction of the evaluation factors to describe the present conditions of conflicts in the selected study area(Sihwa lake), to analyze the problems, and then to explore alternative approaches for resolving the conflicts. As research methodologies, we have depended upon literature review and field survey methods. As field survey methods, we employed structured questionnaires for the various samples from the experts of research institutes, professors, representatives of NGOs and citizens. Survey results suggested that 5 representative elements comprising 35 detailed elements could be identified. Based on these results, this study was able to identify and classify the evaluation factors and help to resolve coastal conflicts in Korea.

• 한국연소학회:학술대회논문집
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• 2004.11a
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• pp.231-237
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• 2004

Vacuum carburizing continues to gain acceptance as an alternative to atmosphere carburizing particularly in the car industry. The advantages of low-pressure carburization over atmospheric gas carburization is not only the creation of a surface entirely free of oxide and the environmentally friendly nature of these methods but also an improvement in deformation behaviour achieved by combining carburization with gas quenching, a reduction in batch times by increasing the carburization temperature, low gas and energy consumption and the prevention of soot to a large extent. In present study, an improved vacuum carburizing method is provided which is effective to deposit carbon in the surface of materials and to reduce cycle time. Also LPC process simulator was made to optimize to process controls parameters such as pulse/pause cycles of pressure pattern, temperature, carburizing time, diffusion time. The carburizing process was simulated by a diffusion calculation program, where as the model parameters are proposed with help the experimental results and allows the control of the carburizing process with good accordance to the practical results. Thus it can be concluded that LPC process control method based on the theoretical simulation and experimental datas appears to provide a reasonable tool for prototype LPC system.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.585-593
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• 2011

Actual fire test under a laboratory and fire simulation by using computer are considered into main methodology in order to estimate and predict fire size of railway train. Even if practical fire size could be obtained from the full-model railway car test such as a large scale cone-calorimeter test, it is not always possible and realistic due to that expensive cost and attendant dangers could in no way be negligible. In this point of view, fire simulation analysis method based on the computational fluid dynamics could be proposed as an alternative and it seems to be also efficient and reasonable. However, simulation results have to be verified and validated in accordance with the proper procedure including comparing analysis with the actual fire test. In this paper, fire load and growth aspect was investigated through the room corner test (ISO 9705) for the mock-up model of the actual railway car. Then, it was compared with the output data derived from the simulation by using Pyrolysis Model of the FDS (Fire Dynamics Simulator, by NIST) for the exact same domain and condition corresponding with pre-performed room-corner test. This preliminary verified and validated fire modeling method could enhance the reliability of output data derived from the fire simulation under the similar domain and condition.

• Archives of Reconstructive Microsurgery
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• v.21 no.2
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• pp.111-117
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• 2012

Purpose: To report the clinical results of the perforated-based propeller flap for lower extremity soft tissue reconstruction. Materials and Methods: Between January 2010 and June 2012, a total of 16 defects in the lower extremities were covered with perforator-based propeller flaps. Retrospective data for location and size of the defect, flap dimension, pedicle artery, pedicle rotation, complications were obtained. Results: Peroneal artery-based perforator flap were used in eleven cases, posterior tibial artery-based perforator flap in two cases, anterior tibial artery-based perforator flap in one case and medial plantar artery-based perforator flap in two cases. The average size of the flaps was $63cm^2$. The marginal skin necrosis of the flaps as a complication was developed in two cases, one of which was covered with split-thickness skin graft. There were no functional deficits from the donor site. Conclusion: For the reconstruction of lower extremities, the perforator-based propeller flap could be a reasonable alternative as it is a simple, safe and versatile technique.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.6
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• pp.457-463
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• 2018

This paper compares the results of ${\Sigma}{\Delta}-STAP$ applied to actual radar test data and simulation data. The radar received a target signal from a virtual target generator and the clutter signal from a signal generator in an anechoic chamber. The simulation data were generated from ideal baseband radar signal modeling using the same parameter as that for the test radar. The ${\Sigma}{\Delta}-STAP$ results of the test and simulation data are similar in terms of the target signal shape and noise level. The SINR(Signal-to-Interfrence-plus-Noise Ratio) loss also had similar aspects, but the simulation result shows 1~2 dB higher SINR loss than the test result. This result verified that the simulation data can be a reasonable alternative test data when the ${\Sigma}{\Delta}-STAP$ is applied.