• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.2
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• pp.138-143
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• 2006

This paper presents intelligent digital redesign method for hybrid state space fuzzy-model-based controllers. For effectiveness and stabilization of continuous-time uncertain nonlinear systems under discrete-time controller, Takagi-Sugeno(TS) fuzzy model is used to represent the complex system. And global approach design problems viewed as a convex optimization problem that we minimize the error of the norm bounds between nonlinearly interpolated linear operators to be matched. Also, by using the bilinear and inverse bilinear approximation method, we analyzed nonlinear system's uncertain parts more precisely. When a sampling period is sufficiently small, the conversion of a continuous-time structured uncertain nonlinear system to an equivalent discrete-time system have proper reason. Sufficiently conditions for the global state-matching of the digitally controlled system are formulated in terms of linear matrix inequalities (LMIs). Finally, a TS fuzzy model for the chaotic Lorentz system is used as an . example to guarantee the stability and effectiveness of the proposed method.

• Journal of Technologic Dentistry
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• v.16 no.1
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• pp.78-104
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• 1994

Under the fee for service schedule of Korean health insurance system, rational fee for dental laboratory products based on the cost is required to be formulated. The purpose of this study was to find actual cost of dental laboratory products in case of a University Hospital. Materials of this study were used as follows : 1. Balance sheet at Dec. 31, 1992 and profit and loss report of the year 1992 of the sample hospital 2. Performance report of dental laboratory department. 3. Purchasing and other accounting bills of dental laboratory materials. The following methods were used. 1. Actual cost finding of dental laboratory department was performed. 2. Work sampling methods were used for measuring standard working time by the process of working. 3. To porcelain fused to metal crown(non-precious), Relative value of the cost of dental laboratory products was calculated as 1.00. 4. Fee and cost of those products were compared on the basis of Relative values. The results of the study can be summarized as follow : 1. Overall, it took longs time than other items. to product denture-related items. 2. When several teeth are made in a time, average production time is much sorter than when one tooth is made in a time. 3. The relative price cost of Dicor cast crown and denture related items are higher than the criterion items. 4. The material cost occupies average 11% out of the total price cost, proportion of personnel expenses is average as 60.0%. 5. Some of the components consisting of the price cost are not reflected adequately in setting the level of the reimbursement price. 6. Relative values of dental laboratory products price cost are varied in the range from 0.05 to 2.83, overall, the reimbursement price of dental products appears not to reflect adequately the price cost. On the basis of this study results, the following ideas would be suggested : 1. Fee Schedule of dental laboratory products should be renovated in order to reflect their costs. 2. Dental laboratory product manufacturers should be enlarged for the economy of scale which may be useful for cost- containment. 3. Dental laboratory producters themselves are required to be standardiqed according to the categories of skill.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.10
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• pp.1849-1854
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• 2009

This paper describes the design, evaluation and implementation of a compensating algorithm for an iron-cored measurement current transformer (CT) that removes the effects of the hysteresis characteristics of the iron-core. The exciting current resulting from the hysteresis characteristics of the core causes an error of the CT. The proposed algorithm decomposes the exciting current into the core loss current and the magnetizing current and each of them is estimated. The core loss current is calculated from the secondary voltage and the voltage-core loss current curve. The core flux linkage is calculated and then inserted into the flux-magnetizing current curve to estimate the magnetizing current. The exciting current at every sampling interval is obtained by summing the core loss and magnetizing currents and then added to the measured current to obtain the correct secondary current. The voltage-core loss current curve and flux-magnetizing current curves, which are different from the conventional curves, are derived in this paper. The performance of the proposed algorithm is validated under various conditions using EMTP generated data. The experimental test results of an iron-core type electronic CT, which consists of the iron-core and the compensation board, are also included. The results indicate that the proposed algorithm can improve the accuracy of the measurement CT significantly, and thus reduce the size and the cost of the CT.

• Journal of Pharmacopuncture
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• v.7 no.1 s.12
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• pp.15-26
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• 2004

Background : This study was conducted to evaluate the effects of wild ginseng herbal acupuncture developed for the intravenous use. Healthy male and female volunteers(n=57) went through Randomized Control Trials(RCT). Methods : For those who are under a medication due to common cold or other illnesses were excluded in the primary stage and the subjects with possible abnormalities in the pre-screening process were also excluded in the secondary stage. Then the examination groups were determined by random sampling. Experiment groups were divided into Normal saline injection group(control group), cultivated wild ginseng herbal acupuncture group(experiment group 1) and natural wild ginseng herbal acupuncture group(experiment group 2) Blood tension, body temperature, pulse, and other criteria were measured and analyzed. Results : 1. Intravenous injection of cultivated wild ginseng herbal acupuncture and natural wild ginseng herbal acupuncture didn't cause significant changes in the blood tension, pulse, body temperature, and etc. 2. No significant differences were witnessed in CBC, ESR, biochemistry of blood test and UA between the experiment groups. 3. No significant changes were noted in the thermography before and after the test in the experiment groups. 4. Some of the common physical changes occurring during and after the administration were fatigue, chest distension, and headache in all of the experiment groups. 5. Comparing general condition after one week from the termination of administration, the control group showed worst condition while as the natural wild ginseng herbal acupuncture group displayed best condition. Conclusion : From the above results, we can carefully deduce that the intravenous injection of the wild ginseng herbal acupuncture didn't show significant differences compared to injection of the normal saline. We can infer it is safe on the human body and further studies and reports must be followed.

• Korean Journal of Community Nutrition
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• v.21 no.5
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• pp.451-462
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• 2016

Objectives: This study was designed with the goal of understanding the factors affecting the frequency of skipping meals of prime-aged mothers with children as well as their nutritional status. Methods: Utilizing data from the 2010-2011 Korea National Health and Nutrition Survey, the frequency of skipping meals of mothers aged between 30 to 49 years with children aged between 3 to 11 years during a two day period was statistically analyzed. The number of meals skipped calculated and categorized into skipping no meals, skipping one meal, skipping two meals or more. Results: Compared to subjects who corresponded to mean nutrient adequacy ratio(MAR) of 4 quartile, subjects who corresponded to MAR of 2 quartile had 2.766 (95% CI: 1.552-4.931) probability of being in the 1 meal skippers group, while the probability of being in the more than 2 meals skippers group was 2.743(95% CI: 1.353-5.564). Also, compared to subjects who corresponded to MAR of 4 quartile, subjects who corresponded to MAR of 1 quartile had 3.471 (95% CI: 1.871-6.442) probability of being in the 1 meal skippers group, while the odds ratio for being in the more than 2 meals skippers group was 5.258(95% CI: 2.642-10.466). Conclusions: The results have the advantage of being generalized because the study selected subjects from probability sampling of the female population of Korea. The research results showed that the elements influencing skipping meals of prime-aged mothers with children were mean nutrient adequacy ratio and the number of nutrients, under estimated average requirement intake, and others. Therefore, to encourage dietary behaviors in the right direction, an integrated approach that considers the associated factors must be realized. Future studies are needed to understand how the frequency of skipping meals of mothers affects their children.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1313-1319
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• 2013

The purpose of this study was to survey body image according to BMI. The subjects were 600 students, data were collected by questionnaire surveys using convenience sampling and analyzed by the SPSS 20.0 program. Body mass index(BMI) and body image between high school and college students were significantly different. Although significant difference between two groups, BMI of high school and college students among women were not significant difference. BMI and body image according to gender were significantly different. Body image according to BMI between men and women were significantly different and expecially subjects of under weight had highest body image(F =15.86, p <.001). These results mean that body weight misunderstood by the early adulthood. It is needed to revise of perception on their own body weight in order to improve body image.

• The Journal of Korean Society for School & Community Health Education
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• v.16 no.1
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• pp.27-38
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• 2015

Objectives: The purpose of this study is to develop programs that help students adjust to school and provide basic data for the students who have difficulty adjusting to school by analyzing the influence of elementary school students' stress and their relationship with parents on school adjustment. Methods: The study surveyed fourth graders in 3 elementary schools in G district. The researcher used convenience sampling to select the 3 elementary schools. The combined 158 students were selected for the analysis, and the survey was conducted for a month in September 2011. The stress monitoring tool used in the 5th year of Korean Youth Panel Survey was mobilized to measure levels of stress among the participants. To measure the parent-child relationship, the Korean Parent-Child Relationships Scale was used. For the measurement of school adjustment, a tool designed to identify the school adjustment of elementary school students was used. The SPSS 21 software and a two-sided test under the significance level of ${\alpha}=0.05$ were used to analyze data. The regression analysis was also used to identify the relative influence of the stress and parent-child relationship on children's adjustment to school. Results: The regression analysis has found the following: the higher peer stress (B=-0.175) and parental strictness (B=-0.159) grow, the lower the level of school adjustment gets; the higher the level of intimacy between parent and child gets, the higher the level of school adjustment grows; and intimacy between parent and child (${\beta}=0.400$) has the largest influence on the child's school adjustment. Conclusions: For elementary school students to be well adjusted to school, their stress and relationships with their parents should be managed. In particular, using the programs that can reduce stress from peers and increase parent-child intimacy will be effective in helping students adjust to school.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.4
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• pp.662-666
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• 2011

In this study, distribution characteristics of dioxins in soils in Busan, Korea were investigated regarding different land use types. Soil sampling sites that distributed through the Busan city showed dioxin concentration ranging from 0.489 to $322.736pg-TEQ\;g^{-1}$ dry weight with a mean value of $26.257pg-TEQ\;g^{-1}$ dry weight. The mean dioxin concentrations of investigated soils ranged from 1.554 to $50.357pg-TEQ\;g^{-1}$ dry weight in consideration of each land use type. That in metal refinery sites with $50.357pg-TEQ\;g^{-1}$ dry weight was higher than any other sites, followed by waste incinerator sites with $44.285pg-TEQ\;g^{-1}$ dry weight. The majority of soil samples had the same dioxin congener profiling despite the different range of dioxin concentration. Octa-CDD was the major contributor among seventeen dioxin congeners with the range from 29.5 to 70.1% in real values. In contrast to real values, dioxin congener profiles in TEQ values were dominated by 2,3,4,7,8-PeCDF which contributed about 35.3~43.8% to the total dioxin concentrations. It was judged by these results that penta-CDF was the major contributor of soil samples in Busan city. The mean ratio of PCDFs/PCDDs in real values was about 0.71, but that in TEQ values was, in contrast to it, approximately 3.03.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.2
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• pp.207-212
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• 2011

A hydraulic breaker is an attachment installed at the end of excavator arm and is used for breaking. As per the authors' knowledge, there have been no research results on reducing the weight of the hydraulic breaker even though this weight reduction is very important for improving the performance of the excavator. In this study, we minimize the weight of the housing of the hydraulic breaker under normal operating conditions, while the maximum stress of the housing is lower than the allowable stress. A meta-model, which is generated by using the CAE results for the sampling design points determined by an orthogonal array, is used to solve the minimization problem. The weight of the housing according to the optimal design is found to be lower than the original weight by 4.8% while satisfying the constraint on the maximum stress.

• Journal of Preventive Medicine and Public Health
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• v.44 no.6
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• pp.267-274
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• 2011

Objectives: We examined health care disparities in Korean urban homeless people and individual characteristics associated with the utilization of health care. Methods: We selected a sample of 203 homeless individuals at streets, shelters, and drop-in centers in Seoul and Daejeon by a quota sampling method. We surveyed demographic information, information related to using health care, and health status with a questionnaire. Logistic regression analysis was adopted to identify factors associated with using health care and to reveal health care disparities within the Korean urban homeless population. Results: Among 203 respondents, 89 reported that they had visited health care providers at least once in the past 6 months. Twenty persons (22.5%) in the group that used health care (n = 89) reported feeling discriminated against. After adjustment for age, sex, marital status, educational level, monthly income, perceived health status, Beck Depression Inventory score, homeless period, and other covariates, three factors were significantly associated with medical utilization: female sex (adjusted odds ratio [aOR, 15.95; 95% CI, 3.97 to 64.04], having three or more diseases (aOR, 24.58; 95% CI, 4.23 to 142.78), and non-street residency (aOR, 11.39; 95% CI, 3.58 to 36.24). Conclusions: Health care disparities in Seoul and Daejeon homeless exist in terms of the main place to stay, physical illnesses, and gender. Under the current homeless support system in South Korea, street homeless have poorer accessibility to health care versus non-street homeless. To provide equitable medical aid for homeless people, strategies to overcome barriers against health care for the street homeless are needed.