• Water Engineering Research
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• 제4권3호
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• pp.127-139
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• 2003

This paper presents the hydraulic analysis of the oxygen transfer through the air entrainment and the relationships between the efficiency of the oxygen transfer and the hydraulic parameters in the riparian riffles. Field survey on the pool-riffle formation of the river reach and the measurements of the oxygen transfer in the riffles were performed. Air entrainment occurred more frequently in the edged gravels rather than in the round and edgeless ones, and it was formed mainly from behind the trailing edges of the gravels. Oxygen transfer was found to be proportional to the flow velocity, the flow discharge, and the Froude number, but to be not closely related to the particle diameter. Average value of oxygen transfer in the riffles of study area was about 0.085, which shows good efficiency compared with results of smooth chute. Variation of the water level, which increases in proportion to the flow velocity and the flow discharge, seems to make the air entrainment more active, but has not been verified quantitatively. Relationships between the air entrainment and the variation of the water level must be considered in the further study.

• Journal of Information Technology Services
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• 제12권4호
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• pp.187-204
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• 2013

In this study, we developed a comprehensive model to measure the National Information Security Level based on PRM framework. The proposed model reflected a rapidly changing technology environments such as social network service, mobile devices, and etc. This new model consists of three layers:Infrastructure Layer, the Action Layer and the Performance Layer, and there are 16 sub-indexes under the 3 layers. To develop new model and sub-indexes for measuring the National Information Security Level, much amounts of documents related to security indexes or deliberation criteria and security guidelines from international organization were reviewed and then most probable index pool were composed. The Index pool were verified by expert group consisting of professors and specialists. Through five times of screening and having an evaluation review, 16 sub-indexes were deduced and then Delphi and AHP have been conducted to obtain validity and objectiveness of the indexes. Thus the new proposed national information security index will show more exact national information security level and we expect that the indexes give much implications for establishing information protection policy.

• Journal of the Korean Applied Science and Technology
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• 제36권4호
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• pp.1224-1234
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• 2019

This study examines the relationship between service quality, satisfaction and customer loyalty of children's pool. The population distributed a questionnaire to a sample of 300 subjects, and a total of 297 questionnaires were used for data analysis, excluding 3 questionnaires that were determined to be unsatisfactory among the collected questionnaires. In this study, frequency analysis, reliability analysis, exploratory factor analysis, correlation analysis, multiple regression analysis, and simple regression analysis were performed using PASW 21.0. In this study, the significance level of all statistics was set to .05 and the following conclusions were drawn. First, facilities, programs, costs, human resources, and trust in the service quality of children's pools were found to affect satisfaction. Second, the cost, personnel nursery, and trust of the children's pool service quality were found to affect customer loyalty. Third, satisfaction with the service quality of the children's pool affects customer loyalty.

• Nuclear Engineering and Technology
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• 제48권4호
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• pp.881-892
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• 2016

Following the Fukushima accident and its extended station blackout, attention was brought to the importance of the spent fuel pools' (SFPs) behavior in case of a prolonged loss of the cooling system. Since then, many analytical works have been performed to estimate the timing of hypothetical fuel uncovery for various SFP types. Experimentally, however, little was done to investigate issues related to the formation of a flammable gas mixture, distribution, and stratification in the SFP building itself and to some extent assess the capability for the code to correctly predict it. This paper presents the main outcomes of the Experiments on Spent Fuel Pool (ESFP) project carried out under the auspices of Swissnuclear (Framework 2012-2013) in the PANDA facility at the Paul Scherrer Institut in Switzerland. It consists of an experimental investigation focused on hydrogen concentration build-up into a SFP building during a predefined scaled scenario for different venting positions. Tests follow a two-phase scenario. Initially steam is released to mimic the boiling of the pool followed by a helium/steam mixture release to simulate the deterioration of the oxidizing spent fuel. Results shows that while the SFP building would mainly be inerted by the presence of a high concentration of steam, the volume located below the level of the pool in adjacent rooms would maintain a high air content. The interface of the two-gas mixture presents the highest risk of flammability. Additionally, it was observed that the gas mixture could become stagnant leading locally to high hydrogen concentration while steam condenses. Overall, the experiments provide relevant information for the potentially hazardous gas distribution formed in the SFP building and hints on accident management and on eventual retrofitting measures to be implemented in the SFP building.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제18권11호
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• pp.2664-2669
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• 2014

Recently, many research efforts have paid attention to spectrum pooling meshanism that provides efficient way to manage transient spectrum requests of secondary users in cognitive radio networks. Spectrum pooling is maintained by WSP (wireless service provider). WSP leases the spectrums stored in her spectrum pool to secondary users with being paid for it. It is natural that WSP tries to get profits as much as possible, which implies the WSP tries to minimize the cost required for maintaining her spectrum pool. In this paper, we model the spectrum pool into a probabilistic inventory model. Assuming secondary users' spectrum requests follow normal distribution, we give a strategic way that minimizes the maintenance cost of the spectrum pool. By a series of simulations, we show that WSP can reduce the total maintenance cost through our inventory model-based spectrum pooling than maintaining fixed inventory level.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국정보통신학회 2014년도 추계학술대회
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• pp.338-341
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• 2014

Recently, many research efforts have paid attention to spectrum pooling meshanism that provides efficient way to manage transient spectrum requests of secondary users in cognitive radio networks. Spectrum pooling is maintained by WSP (wireless service provider). WSP leases the spectrums stored in her spectrum pool to secondary users with being paid for it. It is natural that WSP tries to get profits as much as possible, which implies the WSP tries to minimize the cost required for maintaining her spectrum pool. In this paper, we model the spectrum pool into a probabilistic inventory model. Assuming secondary users' spectrum requests follow normal distribution, we give a strategic way that minimizes the maintenance cost of the spectrum pool. By a series of simulations, we show that WSP can reduce the total maintenance cost through our inventory model-based spectrum pooling than maintaining fixed inventory level.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 추계 학술대회논문집
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• pp.39-44
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• 2005

In HANARO, a multi-purpose research reactor of 30 MWth, the emergency water supply system consists essentially of an emergency water storage tank located in the level of about thirteen meter (13 m) above the reactor core, a three inch ('3\%') diameter water injection pipe line including injection valves from the tank to the reactor cooling inlet pipe and a test loop to do periodic system performance test. When the water level of the reactor pool comes down to the extremely low due to a loss of reactor pool water accident the emergency water stored in the tank should be fed to the core by the gravity force and at that time the design flow rate is eleven point four kilogram per second (11.4 kg/s). But it is impossible periodically to measure the injection flow rate under the emergency condition because the normal water level should be maintained during the reactor operation. This paper describes a flow network analysis to simulate the flow rate under the emergency condition. As results, it was confirmed through the analysis results that the calculated flow rate agrees with the design requirement under the emergency condition.

• Proceedings of the KIEE Conference
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.391-393
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• 2000

This paper presents an new algorithm for the economic load dispatch considering the reliability level constraints of composite power system under deregulated electricity market. It is the traditional ELD problem that generation powers have been dispatched In order to minimize total fuel cost subjected to constraints which sum of powers generated must equal the received load and no violating lower and upper limit constraints on generation. Under deregulated electricity market, however, generation powers of a pool have to be reallocated newly in order to satisfy the reliability differentiated level required at a load point because of a reliability differentiated electricity service which is a part of the priority service. In this study, new economic load dispatch algorithm for reallocating the generation powers of a pool in order to satisfy the reliability differentiated level under deregulated competitive electricity market is proposed. The uncertainties of not only generators but also transmission lines are considered fer the reliability evaluation. The characteristics and effectiveness of this methodology are illustrated by the case studies on MRBTS and IEEE-RTS.

• Journal of the Korean Society of Food Science and Nutrition
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• 제21권5호
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• pp.580-593
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• 1992

Cholesterol have many essential functions as a component of cellular and subcellular membranes, metabolic precursor of bile acids and steroid hormones, and obligatory part of the metabolic systems involved in DNA synthesis and cell division. These essential funtions demand a continuous and appropriate supply of cholesterol to the tissues. Body cholesterol pool is maintained by the balance of acquirement from diets, de novo synthesis, and excretion either as bile acids or neutral steroids. In these metabolic process, cholesterol biosynthesis is controlled by the change in the activity of 3-hydroxy-3methylglutaryl coenzyme A (HMG-CoA) reductase. Under most physiological or nutritional situations, the activity of this enzyme is adroitly regulated to maintain tissue cholesterol balance. Excess cholesterol accumulation in the cells induces the decrease in the number of LDL-receptor, followed by the increase in the level of serum LDL-cholesterol. Increase in the level of serum cholesterol appears to be an important determinant for the incidence of the coronary heart disease. Dietary intervention may be helpful in alleviating an increase in the level of serum cholesterol or body cholesterol pool.

• Korean Institute of Interior Design Journal
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• 제22권1호
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• pp.328-338
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• 2013

This study aims at exploring the characteristics of interior design of the Cruise line running Korea, Japan and China, and the satisfaction level of the Korean passengers for the interior design. Literature review and the physical traces of the cruise ship interior including 4 types of cabins and public spaces such as main hall, restaurants, outdoor swimming pool, jogging track, theater, meeting room, duty-free shop were performed. Also, the questionnaire to the passengers were used to understand their preferences and satisfaction level for each space. The results show that the passengers are very satisfied with the color and atmosphere of the cabin, while they complain the inconvenience of the bathroom size. Also in the public space, they prefer western classic style and modern style rather than Asian or Korean style. This means that they want the exotic feeling coming out of home. Also they prefer buffet restaurant, duty-free shop, theater, observation platform compared to other public spaces. However, the problem is that there are no place for the Korean family members with young children except for the outdoor pool. The interior and the program should be redesigned for the public spacs such as cinema room, family karaoke and internet-free room for Korean passengers.