• Journal of Communications and Networks
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• v.15 no.5
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• pp.527-537
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• 2013

Improving resource utilization has been a hot issue in heterogeneous wireless networks (HWNs). This paper proposes a radio resource management (RRM) method based on access proportion optimization. By considering two or more wireless networks in overlapping regions, users in these regions must select one of the networks to access when they engage in calls. Hence, the proportion of service arrival rate that accesses each network in the overlapping region can be treated as an optimized factor for the performance analysis of HWNs. Moreover, this study considers user mobility as an important factor that affects the performance of HWNs, and it is reflected by the handoff rate. The objective of this study is to maximize the total throughput of HWNs by choosing the most appropriate factors. The total throughput of HWNs can be derived on the basis of a Markov model, which is determined by the handoff rate analysis and distribution of service arrival rate in each network. The objective problem can actually be expressed as an optimization problem. Considering the convexity of the objective function, the optimization problem can be solved using the subgradient approach. Finally, an RRM optimization scheme for HWNs is proposed. The simulation results show that the proposed scheme can effectively enhance the throughput of HWNs, i.e., improve the radio resource utilization.

• Journal of Korean Society on Water Environment
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• v.26 no.1
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• pp.140-147
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• 2010

In existing design method for aeration tank water temperature was considered as governing variable for applying safety factor. This study tried a few new approach of aeration tank design using SOUR at various temperature conditions. Specific substrate utilization rate (U) and specific oxygen uptake rate (SOUR) both were analyzed at various temperature and SRT. The laboratory scale reactor was operated on various temperature ($10^{\circ}C$, $20^{\circ}C$, $25^{\circ}C$) and SRT (5day, 10day, 20day, 30day). In this study, SOUR tended to increase with the temperature increased. On the other hand, SOUR tended to decrease when SRT increased from 5 days to 30 days. Empirical equations were obtained SOUR=a/SRT+b and $SOUR=(a/m){\cdot}U+(b-a(n/m))$ from the relationship between SRT, U and SOUR. Empirical equations shows the possibility as a new design method for the aeration basin.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.176-179
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• 2003

Fuel oxygenates, such as Methyl tertiary Butyl Ether (MTBE) is additive in gasoline used to reduce air pollution. Gasoline components and fuel additives can leak form underground storage tanks. MTBE is far more water soluble than gasoline hydrocarbons like BTEX then it travels at essentially the same velocity as groundwater. MTBE in drinking water causes taste and odor problems. Therefore, the purpose of the this study is to examine the ability of ground rubber to sorb MTBE form water. The study consisted of running both batch and column tests to determine the sorption capacity and the flow through utilization efficiency of ground rubber. The result of Column test indicate that ground tire rubber has on the 36% utilization rate. Finally, it is clear that ground rubber present an attractive and relatively inexpensive sorption medium for a MTBE. The Author thought that to determine the economic costs of ground rubber utilization, the cost to sorb a given mass of contaminant by ground rubber will have to be compared to currently accepted sorption media.

• Journal of Communications and Networks
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• v.16 no.2
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• pp.209-216
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• 2014

Cognitive radio (CR) has been proposed to solve the spectrum utilization problem by dynamically exploiting the unused spectrum. In CR networks, a spectrum selection scheme is an important process to efficiently exploit the spectrum holes, and an efficient channel allocation scheme must be designed to minimize interference to the primary network as well as to achieve better spectrum utilization. In this paper, we propose a multichannel selection algorithm that uses spectrum hole prediction to limit the interference to the primary network and to exploit channel characteristics in order to enhance channel utilization. The proposed scheme considers both the interference length and the channel capacity to limit the interference to primary users and to enhance system performance. By using the proposed scheme, channel utilization is improved whereas the system limits the collision rate of the CR packets.

• KDI Journal of Economic Policy
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• v.45 no.1
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• pp.33-68
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• 2023

The present article investigates empirically whether non-reciprocal trade preferences (NRTPs) offered by QUAD countries (Canada, the European Union, Japan, and the United States) to developing countries have helped to promote economic growth in the beneficiary countries. Two main blocks of NRTPs are considered here: Generalized System of Preferences (GSP) programs and other trade preferences programs. The analysis used a set of 90 beneficiary countries of NRTPs that are concurrently recipients of development aid over the period of 2002-2018. Using the two-step system generalized method of moments, the analysis indicated that while a higher degree of utilization of each of these two blocks of NRTPs has been associated with a high economic growth rate, development aid enhances this positive effect. This highlights the need for donors to support a development strategy based on the provision of both development aid and NRTPs if they are to help beneficiary countries to promote economic growth. Finally, when the positive economic growth effect of the utilization of NRTPs is higher, the result is a greater country's share of exports (under preferential tariffs) to QUAD countries out of their total merchandise exports.

• Health Policy and Management
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• v.1 no.1
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• pp.27-41
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• 1991

The purpose of this study is to estimate cesarean section rate in Korea and analyze characteristics of health care institution which affect regional variation in the rate. We have searched vaginal and cesarean section deliveries among Diagnosis Related Group dat based upon insurance claim bills which have been submitted to Korean Insurance Corporation for two years since March, 1985. The results are as follows: 1. Out of all delivery cases of 87,500, cesarean section rate was 16.3% (14,299 cases). 2. Cesarean section rate varied according to size and ownership of health care institutions. In above 6- bed sized hospitals, the rate was at about 20% higher than small sized institutions, but rather in hospitals that have more than 500 beds, it was somewhat low. Classified by the hospital ownership, the rate was low at 18.4% in hospitals of religious organization and highest at private or corporate hospitals. 3. This study shows large regional variation in cesarean section rate; there are two times differences between region with the highest and lowest rate. Strongly related factors in that variation was the ownership of health care institution and urbanization variables. Low level of cesarean section rate in a region is explained by high proportion of delivery cases at institutions of religious organization and at insitutions in county level site. This result shows that apart from medical conditions of patients, indications of cesarean section differs from health care providers, and especially ownership of institution strongly affect them. Cesarean section rate in Korea is supposed to be at high level and development of utilization review programs to keep appropriate cesarean section rate is needed.

• Journal of Preventive Medicine and Public Health
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• v.41 no.4
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• pp.241-248
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• 2008

Objectives: The purpose of the study was to identify a gap between consumer characteristics and utilization of health information on the Internet. Methods: A telephone survey of nationally representative samples was conducted using structured questionnaires, and 1,000 of the 1,189 responses obtained were included in our analysis. The following variables were included in the analysis as potential predictors of health information use on the Internet: predisposing factors such as gender, age, and education status; enabling factors such as region and monthly household income; consumer need for health information; and attitude to health. Multiple logistic regression analysis was used to evaluate the association between utilization rate and the potential predictors. Results: Thirty-nine percent of consumers had obtained health information on the Internet over a one-year period. The utilization rates were higher for consumers who were young, educated, worked in the office setting, had higher incomes, wanted health information, and were able to use the Internet. The utilization rate was 5.35 times higher in the younger group (20-30 years) than in the elderly group (95% CI=2.21-12.97); 2.21 times higher for office workers than for manual workers (95% CI=1.16-4.20); 3.61 times higher for college graduates than for middle school graduates and below (95% CI=1.07-11.59); 1.99 times higher for people with monthly household incomes over 3,000,000 won than for those with monthly household incomes below 1,500,000 won (95% CI=1.01-3.92). Conclusions: There needs to be a paradigm shift, with consideration of not only Internet accessibility in the digital age, but also consumer ability and attitudes toward utilization of health information.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.3
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• pp.157-165
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• 2017

Being a staple food for more than half of the population of the world and South Korea, rice is an important crop. For the past 20 years, global paddy rice cultivation area and production have shown an annual growth of 0.46% and 1.61%, respectively. Global rice consumption for food and processing has increased by 1.37% and 3.68%, respectively. Due to the main reason for such increasing human population, it is expected that from 439 million tons in 2010, additional 116 million tons will be needed in 2035. Global rice imports and exports have doubled in the last 20 years. However, in spite of such increment, global rice exports in 2013 were 8.4% of the total production. It is thought that rice protection policies in the producing countries are the main reason for such small scale of rice trading. In the past 5 years, India recorded the largest growth rate in rice exports (51.4%), whereas China showed the largest growth rate in imports (61.0%). For global utilization of milled rice during the same period, approximately 79.4% was used as food, 7.2% as animal feeds, and 1.4% for processing. Regionally, Asia has shown a similar pattern to the global rice usage, whereas utilization for processing in America, for food in Africa, and for animal feed in Europe was relatively higher than the global rice usage. Korea's cultivation area and production since the last 5 years, are 0.5% and 0.8% of those of the world, respectively. Its annual rice export is approximately 3,000 tons, which is 0.01% of the global rice export. Korea's rice utilization is high for food and low for feed and for processing relative to global rice utilization. Therefore, a review must be conducted to increase Korea's utilization of rice for processing and for feed production.

• Fisheries and Aquatic Sciences
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• v.20 no.5
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• pp.7.1-7.6
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• 2017

A feeding trial was designed to assess the effects of dietary protein and lipid content on growth, feed utilization efficiency, and muscle proximate composition of juvenile mandarin fish, Siniperca scherzeri. Six experimental diets were formulated with a combination of three protein (35, 45, and 55%) and two dietary lipid levels (7 and 14%). Each diet was fed to triplicate groups of fish ($8.3{\pm}0.1g$) to apparent satiation for 8 weeks. The results showed that growth performance in terms of weight gain (WG) and specific growth rate (SGR) increased with increasing dietary protein level from 35 to 55% at the same dietary lipid level. At the same dietary lipid content, WG and SGR obtained with diets containing 55% protein was significantly higher than those obtained with diets containing 45 and 35% protein. No significant effect on growth rate was found when the dietary level of lipid was increased from 7 to 14%. While the levels of protein and lipid in the diets had no significant effect on feed intake, other nutrient utilization efficiency parameters including daily protein intake (DPI), feed efficiency (FE), and protein efficiency ratio (PER) showed a similar trend to that of growth rates, with the highest values obtained with diets containing 55% protein. Muscle chemical composition was not significantly affected by the different dietary treatments for each dietary lipid or protein level tested. These findings may suggest that a practical diet containing 55% protein and 7% lipid provides sufficient nutrient and energy to support the acceptable growth rates and nutrient utilization of mandarin fish juveniles.

• Health Policy and Management
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• v.30 no.4
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• pp.451-459
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• 2020

Background: Although Korean government have been adopting several policies to expand coverage of National Health Insurance (NHI) program, the coverage rate is still below average across Organization for Economic Cooperation and Development countries. This study was to identify public perception on appropriateness of coinsurance rate and factors associated with coinsurance rate in National Health Insurance. Methods: For this cross-sectional study, 507 participants over aged 20 years were recruited from telephone surveys. Respondents experienced at least one and more visiting medical facilities due to medical problems in last 12 months. Demographic factors, socioeconomic positions, and experiences on medical utilization were measured in order to identify factors associated with perception appropriateness of coinsurance rate. Results: The 49.9% (n=209) of the public responded that the coinsurance rate of NHI program was appropriate. There were no differences in positive perception according to socio-demographic factors and experiences on medical utilization except for gender, residential area, and felt expensive when using medical services. People who felt burden of medical expenditure were more likely to perceive coinsurance rate inappropriate (odds ratio, 2.33; 95% confidence interval, 1.52-3.58) Conclusion: In spite of the relatively low coverage rate of NHI, this study identified that 49.9% of the public perceived the current coinsurance rate was adequate. However, people who felt the burden of medical expenditure were still had a negative perception of the coinsurance rate needed to decrease the coinsurance rate.