• Journal of Periodontal and Implant Science
• /
• v.47 no.5
• /
• pp.264-272
• /
• 2017

Purpose: This study evaluated trends in tooth extraction due to acute and chronic periodontal disease (PD) using data from the National Health Insurance Service-National Sample Cohort for 2002-2013. Methods: A random sample of 1,025,340 individuals was selected as a representative sample of the population, and a database (DB) of diagnostic and prescription codes was followed up for 12 years. We used multivariate logistic regression analysis to assess the incidence of total extraction (TE), extraction due to periodontal disease (EPD), and immediate extraction due to periodontal disease (IEPD) according to sociodemographic factors (sex, age, household income, health status, and area of residence). Results: The incidence of tooth extraction was found to be increasing, and at a higher rate for TE in PD patients. In 2002, 50.6% of cases of TE were caused by PD, and this increased to 70.8% in 2013, while the number of cases of IEPD increased from 42.8% to 54.9% over the same period. The incidence rates of extraction due to acute and chronic PD increased monotonically. We found that the incidence rates of TE, EPD, and IEPD were all 2-fold higher among patients with high income levels and those who were not beneficiaries of health insurance. Conclusions: The rates of TE, EPD, and IEPD have been steadily increasing despite dental healthcare policies to expand public health insurance coverage, increasing the accessibility of dental clinics. Moreover, the effects of these policies were found to vary with both income and education levels. Consistent patient follow-up is required to observe changes in trends regarding tooth extraction according to changes in dental healthcare policies, and meticulous studies of such changes will ensure optimal policy reviews and revisions.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.13 no.3
• /
• pp.601-608
• /
• 2018

While the legislation on the protection of personal information in public institutions was enacted and amended, the guidelines and laws on information security were focused, contracted and realized with focus on specific institutions. Mutual laws and guidelines have been applied and realized for the dual purpose of securing both the asset of macroscopic information and the asset of personally identification information, which are mutually different media information. However, in a bid to present the definition and direction of the fourth industrial revolution in 2017, a variety of products and solutions for security designed to ensure the best safety line of the 21st century, and the third technology with the comprehensive coverage for all these fields, a number of solutions and technologies, including IOT(: Internet of Things), ICT Internet of Things(: ICT), ICT Cloud, and AI (: Artificial Intelligence) are pouring into the security market as if plastic doll toys were manufactured in massive scale into the market. With the rising need for guaranteeing the interrelation for securities with dualistic physical, administrative, logical and psychological differences, that is, information security and personal information security that are classified into two main categories and for the enhanced security for integrated management and technical application, the study aims to acquire the optimal security by analyzing the interrelationship between the two cases and applying it to the study results.

• The Journal of the Korea Contents Association
• /
• v.17 no.6
• /
• pp.504-513
• /
• 2017

This study investigated one of the controversial issues on debate or even controversial between policy makers at the government and corporate levels: To examine any financial determinants on the cash holdings of the firms in the advanced and emerging capital markets. Futhermore, it focused on the large representative firms headquartered in the U.S. and the Republic of Korea, taking into account scarcity of the previous literature concentrated on the comparative studies on this particular subject. Several legitimate, but robust econometric estimations such as static and dynamic panel data models and Tobit regression, were applied to investigate possible financial factors ono the cash liquidity. Given the continued debates or arguments on the excess cash reserves between interest partied at the government and corporate levels in the advanced and/or emerging capital markets, and more accelerated capital transfers among associated nations by engaging in the arrangements of the FTAs, the results of the study may provide a vision to search for the optimal level of corporate cash holdings for firms in the two nations.

• Journal of Korea Water Resources Association
• /
• v.32 no.5
• /
• pp.537-545
• /
• 1999

This study examines three counterplans for the improvement in price structure of Korean multi-regional water supply system. First, price differentiation between industrial and residential water uses is analyzed using several pricing methods. It has been estimated that the industrial water price by the Ramsey pricing method is needed to be two to two and half times higher than the price of residential water to achieve maximum social welfare. Second, peak-load pricing is then studied to seek for the effectiveness of seasonal differentiation in water price. It has been found that consideration of dam facilities and their functions is the key factor for the effectiveness of the seasonal differentiation in water price. Finally, the discussion about the introduction of contract pricing system to the multi regional water supply system to achieve optimal investment plan for the future water demand is presented. We has found that the introduction of contract pricing system will greatly increase the efficiency in future investment plan of the multi-regional water supply system.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.8 no.8
• /
• pp.1161-1170
• /
• 2013

Currently in 2013, a law that was drawn as a result of social agreement for personal information protection was enacted, and through several amendments, definite policy of written law and guideline were presented for definitive information protection in various fields of social business including IT field. Based on a series of social issues about the importance of personal information, a new access paradigm to personal information appeared. And from macroscopic access method called information protection, the necessity of technical access method came to the fore. Of course, it seems somewhat irrational to restrict all data in the form of personal information to a certain category of information until now. But in the deluge of information based on IT field, it is true that the part of checking the flow of personal information and selecting as security target has been standardized. But still there are cases in which it is difficult to routinely apply the five standardized flows of personal information Life-Cycle-collect, process, provide, store, and destroy-to information that all companies and organizations have. Therefore, the researcher proposes the standardized methodology by proposing the access control methodology for dualised hierarchical personal information Life-Cycle. The results of this research aim to provide practical data which makes optimal access control to personal information Life-Cycle possible.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.11
• /
• pp.239-249
• /
• 2019

Recently, the Korean government has implemented a policy to expand renewable energy sources. Large-scale PV systems are being actively interconnected with the distribution system. On the other hand, when a large-scale PV system is installed and operated, the customer voltages could violate the allowable voltage limit due to reverse power flow of the PV system. To overcome these problems, an enhancement method for hosting the capacity of the PV system in a distribution system is being actively conducted. Therefore, to improve the hosting capacity of the PV system, this paper proposes a model of a reconfiguration of the distribution system, which is composed of three sections and three connections based on PSCAD/EMTDC S/W, and proposes an evaluation algorithm for the feeder reconfiguration to maximize an adaption of the PV system. In addition, this paper presents the optimal method of the feeder reconfiguration section to evaluate the maximum capacity of the PV system to keep customer voltages within the allowable voltage limits based on various operation scenarios, such as the capacity of a PV system and section of feeder reconfiguration. From the simulation results based on the PSCAD/EMTDC modeling and evaluation algorithm, it was confirmed that they are a useful and practical tool to enhance hosting the capacity of a PV system in a distribution system.

• Journal of Chest Surgery
• /
• v.49 no.sup1
• /
• pp.28-36
• /
• 2016

Background: This study aimed to develop the models for regional cardiac surgery centers, which take regional characteristics into consideration, as a policy measure that could alleviate the concentration of cardiac surgery in the metropolitan area and enhance the accessibility for patients who reside in the regions. Methods: To develop the models and set standards for the necessary personnel and facilities for the initial management plan, we held workshops, debates, and conference meetings with various experts. Results: After partitioning the plan into two parts (the operational autonomy and the functional comprehensiveness), three models were developed: the 'independent regional cardiac surgery center' model, the 'satellite cardiac surgery center within hospitals' model, and the 'extended cardiac surgery department within hospitals' model. Proposals on personnel and facility management for each of the models were also presented. A regional cardiac surgery center model that could be applied to each treatment area was proposed, which was developed based on the anticipated demand for cardiac surgery. The independent model or the satellite model was proposed for Chungcheong, Jeolla, North Gyeongsang, and South Gyeongsang area, where more than 500 cardiac surgeries are performed annually. The extended model was proposed as most effective for the Gangwon and Jeju area, where more than 200 cardiac surgeries are performed annually. Conclusion: The operation of regional cardiac surgery centers with high caliber professionals and quality resources such as optimal equipment and facility size, should enhance regional healthcare accessibility and the quality of cardiac surgery in South Korea.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.29 no.3
• /
• pp.125-137
• /
• 1987

The purpose of this paper is to examine some difficulties in water management of agricultural reservoirs in Korea, for there are approximately more than 15,000 reservoirs which are now being utilized for the purpose of irrigation, along with the much amount of expenses and labors to be invested against droughts and floods periodically occurred. Recently, the effective use of water resources in the agricultural reservoirs with a single purpose, is becomming multiple according to the alterable environment of water use. Therefore, the task to allocate agricultural water rationally and economically must be solved for the multiple use of agricultural reservoirs. On the basis of the above statement, this study aims at suggesting the rational method of water management by introducing an optimal technique to allocate the water in an existing agricultural reservoir rationally, for the sake of maximizing the economic effect. To achieve this objective, a reservoir, called "0-Bongje" as a sample of the case study, is selected for an agricultural water development proiect of medium scale. As a model for the optimum allocation of water in the multi-purpose use of reservoirs a linear programming model is developed and analyzed. As a result, findings of the study are as follows : First, a linear programing model is developed for the optimum allocation of water in the multi-purpose use of agricultural reservoirs. By adopting the model in the case of reservoir called "O-Bongje," the optimum solution for such various objects as irrigation area, the amount of domestic water supply, the size of power generation, and the size of reservoir storage, etc., can be obtained. Second, by comparing the net benefits in each object under the changing condition of inflow into the reservoir, the factors which can most affect the yearly total net benefit can be drawn, and they are in the order of the amount of domestic water supply, irrigation area, and power generation. Third, the sensitivity analysis for the decision variable of irrigation which may have a first priority among the objects indicate that the effective method of water management can be rapidly suggested in accordance with a condition under the decreasing area of irrigation. Fourth, in the case of decision making on the water allocation policy in an existing multi-purpose reservoir, the rapid comparison of numerous alternatives can be possible by adopting the linear programming model. Besides, as the resources can be analyed in connection with various activities, it can be concluded that the linear programing model developed in this study is more quantitative than the traditional methods of analysis. Fifth, all the possible constraint equations, in using a linear programming model for adopting a water allocation problem in the agricultural reservoirs, are presented, and the method of analysis is also suggested in this study. Finally, as the linear programming model in this study is found comprehensive, the model can be adopted in any different kind of conditions of agricultural reservoirs for the purpose of analyzing optimum water allocation, if the economic and technical coefficients are known, and the decision variable is changed in accordance with the changing condition of irrigation area.

• Journal of Advanced Navigation Technology
• /
• v.4 no.2
• /
• pp.114-131
• /
• 2000

An airline should consider the number of seats or size of aircraft, when it composes fleet or selects a type of aircraft for some routes. There are two major factors considered for this choice problem under the assumption that the objectives of an airline is a profit maximization: the operating cost and revenue from the aircraft operated. This research tries to solve the problem of aircraft size selection by airline. The study applies four steps to get optimal choice of aircraft size: (1) cost analysis for the relationship between airline operation cost and aircraft size: (2) market share and revenue analysis: (3) flight segment-level analysis, based on the derived cost, demand and revenue functions: and (4) network-level analysis to see how airlines make choice of aircraft size systematically at a network level. An airline can accommodate the increasing air travel demand by either increasing operation frequency, or increasing aircraft size that is represented by seat capacity, or both. Airport runway capacity and productivity depend on the size of aircraft used at airport. This paper presents the understanding of how airlines make decisions on the size of aircraft to operate, how they will adjust their choices when airport capacity is constrained, and how public regulation such as policy for landing fees could influence airlines' aircraft choice.

• Nutrition Research and Practice
• /
• v.14 no.4
• /
• pp.384-400
• /
• 2020

BACKGROUND/OBJECTIVES: Dietary factors are important contributors to cardiometabolic and cancer mortality. We examined the secular trends of nine dietary factors (fruits, vegetables, whole grains, nuts and seeds, milk, red meat, processed meat, sugar-sweetened beverages, and calcium) and the associated burdens of cardiometabolic and cancer mortality in Korea using representative cross-sectional survey data from 1998 to 2016. SUBJECTS/METHODS: Using dietary data from Korean adults aged ≥ 25 years in the Korea National Health and Nutrition Examination Survey (KNHANES), we characterized secular trends in intake levels. We performed comparative risk assessment to estimate the population attributable fraction and the number of cardiometabolic and cancer deaths attributable to each dietary factor. RESULTS: A total of 231,148 cardiometabolic and cancer deaths were attributable to nine dietary risk factors in Korea from 1998 to 2016. Suboptimal intakes of fruits and whole grains were the leading contributors. Although the intakes of fruits, vegetables, and whole grains moderately improved over time, the intake levels in 2016 (192.1 g/d, 225.6 g/d, and 10.9 g/d, respectively) remained far below the optimal levels. Deaths attributable to the low intakes of nuts and seeds (4.5 g/d), calcium (440.5 mg/d), and milk (37.1 g/d) and the high intakes of red meat (54.7 g/d), processed meat (4.7 g/d), and sugar-sweetened beverages (33.0 g/d) increased since 1998. Compared with older age groups (≥ 45 years), more unfavorable changes in dietary patterns were observed in the younger population aged 25-44 years, including more sharply increased intakes of processed meat. CONCLUSIONS: We observed improvement in the intakes of fruits, vegetables, and whole grains and unfavorable changes in the intakes of processed meat and sugar-sweetened beverages over the past few decades. Our data suggest that to reduce the chronic disease burden in Korea, more effective nutritional policies and interventions are needed to target these dietary risk factors.