• Journal of The Korean Astronomical Society
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• v.19 no.2
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• pp.91-107
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• 1986

Making use of our extended version of $\ddot{O}pik's$ convection theory, we have calculated magnetic cycle periods of the sun and late type stars by using Parker's dynamo theory, where we have included the non-linear effect. We presented a relationship between the computed cycle period and spectral type to analyze observed magnetic activities of the late type stars and long-term luminosity variations. It is found that (1) the stellar magentic-cycle period increases towards the later spectral type, (2) the rapid rotation facilitates the activity-related luminosity variation of stars later than about K5, (3) differential rotation plays a critical role in determining the magnetic activity-cycle period, and (4) the non-local effect should be taken into account in order to understand the observed long-term luminosity variations.

• Journal of the Korean Mathematical Society
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• v.43 no.5
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• pp.967-990
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• 2006

In this paper, we evaluate first variations, conditional first variations and conditional Fourier-Feynman transforms of cylinder type functions over Wiener paths in abstract Wiener space and then, investigate relationships among first variation, conditional first variation, Fourier-Feynman transform and conditional Fourier-Feynman transform of those functions. Finally, we derive the conditional Fourier-Feynman transform for the product of cylinder type function which defines the functions in a Banach algebra introduced by Yoo, with n linear factors.

• Health Policy and Management
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• v.8 no.1
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• pp.1-14
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• 1998

Analysis of practice variations has been one of important issues in trying to contain costs as well as to manage quality in health care. This study was conducted to provide statistical model for analysing variations in inpatient costs by type of hospitals. Four K-DRGs including Cesarean section, appendectomy, cataract extraction, and pediatric pneumonia with CC class 0 were selected, and means and dispersions of inpatient procedure and operation costs were simultaneously compared between type of hospitals. The results indicated that joint modelling of means and dispersions by gamma distribution was a very useful analytic tool for identifying factors which might have relationship with variations in inpatient costs. This model can be expanded to test the significance of several independent variables in analysing cost variations. In surgical conditions, means and unit variations of procedure and operation costs showed consistent pattern which was tertiarty hospital, general hospital, and hospital in descending order. Different findings were identified in pediatric pneumonia, from which mean and unit variation of procedure and operation cost was the highest in general hospital. The practical implication of this difference could not be drawn from this study. It will be done by further sophisticated researches. In order to develop health policy for cost containment and quality management in Korea, it is essential to find out manageable factors affecting variations in practice patterns which include characteristics of population, providers, regions, and so on. The statistical model presented in this study will give health services researchers useful insights for future investigations in analysing cost variations.

• Journal of the Korean Home Economics Association
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• v.42 no.9
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• pp.111-134
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• 2004

The purpose of this dissertation is firstly to examine the level of pro-environmental behavior of urban employed wives depending on their life style type and secondly to identify effective ways to promote their pro-environmental behavior. A structured questionnaire interview was conducted with 700 urban employed wives who lived in the Seoul Metropolitan area, and 566 of the responses were valid for analysis. For statistical analysis, this research reviewed the frequencies, percentage, mean, standard deviation(SD), Pearson's correlations, Cronbach's u, factor analysis, cluster analysis, ANOVA, $\chi$$^2$-test, Duncan's Multiple Range Test, and multiple regression using SPSS/PC WIN. The findings of analysis of the study are as follows: 1. Among life style types of employed wives, the order of ecological value was orientation type (37.3%), followed by economical value orientation type (25.8%), uninterested type (18.7%), and convenience-centric value orientation type (18.2%).Pro-environmental behavior scored relatively highly at 3.45 in average. 2. In the analysis of the relationship between life style and background variations, every variation except environmental knowledge was meaningful. 3. In the relationship between pro-environment behavior and background variations, every variation was meaningful except housing types, having helper or not, and environmental knowledge. 4. The recognition level of environmental pollution was important among the variations affecting pro-environmental behavior. 5. There was a difference in pro-environmental behaviors by the following life style types: ecological value orientation, economical value orientation, convenience centric orientation and uninterested. 6. For the relative contribution comparison of background variations (socio-economic variation and environmental variation) and life style variations to the pro-environmental behavior of urban empolyed wives, this research additionally applied each independent variable group. As a result, the explanation level drastically increased in the third step that analyzed the relationship with life style.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.478-486
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• 1993

For satisfactory greenhouse culture, environmental factors must be kept in proper conditions. Therefore, it is important to know relations between environmental conditions and greenhouse systems. In this study, the environment variations and distributions in different types of greenhouses were measured and analyzed. The elements of environment analyzed were temperature , relative humidity, illumination, carbon dioxide and wind velocity. The analyzed greenhouse types were three different types. One of them, A type, was propagation model type by government and the other one, B type, was multiple continuous arches type which was made by farmers himself. The last one, C type, was single arch type which has no environment control system without manual temperature keeping method. The results of this study can be used for reasonable greenhouse environments managements and control.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.563-567
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• 2009

The polymer electrolyte membrane fuel cell(PEMFC) with the advantages of low-operating temperature, high current density, low cost and volume, fast start-up ability, and suitability for discontinuous operation becomes the most reasonable and attractive power system for transportation vehicle and micro-grid power plant in a household. 200W PEM-type FCs system was integrated by this study, then the electrical characteristics and diagnosis of the fuel cell were analyzed with variations on mass flow rate and stack temperature. The ranges of the variations are 1~8L/min on $H_2$ volume and $20{\sim}70^{\circ}C$ on stack temperature.

• Journal of Pharmaceutical Investigation
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• v.36 no.6
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• pp.421-435
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• 2006

The objective of this report is to introduce the European Union's variation rules governing medicinal products that are subject to post-approval changes. The EMEA outlines a variety of changes occurring to approved medicinal products. It also recommends a marketing authorisation holder to follow specific post-approval applications in various situations. For instance, the Commission Regulation(EC) No. 1085/2003 explains variation types and suggests post-authorisation procedures with which an applicant should comply. In all cases of minor and major variations the applicant has to investigate and validate whether or not the intended changes would have impact on the safety, efficacy and quality of a drug product. The applicant should then submit to the EMEA a variation application with adequate documentation in support of the notified changes. This procedure is implemented to ensure that changes to the approved medicinal product do not cause my public health concerns. In fact, the post-authorisation guidance categorizes post-approval changes into type IA/IB variations, type II variations, and extension applications. Such classifications determine administrative procedures to be followed in an efficient manner. Based on the type of a variation, the regulatory agency opts to reduce or extend the evaluation time-frame. The thrust of the EU's post-authorisation guidance is introduced in text with appropriate explanation. All these information will be likely to be helpful in updating a Korean regulatory guidance that could better deal with post-approval changes to generic drugs available in the market.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.61-64
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• 2004

In this paper, we investigated the variations of initial fault current limiting instant according to fault angles in the flux-lock type SFCL. The flux-lock type SFCL consists of the coil 1 and the coil 2 that are wound in parallel each other through an iron core. The operation of the flux-lock type SFCL can be divided into the subtractive polarity winding and the additive polarity winding operations according to the winding directions between the coil 1 and coil 2. The subtractive polarity winding operation could be analyzed with three modes. On the other hand, the additive polarity winding operation could be analyzed with five modes. The variations of initial fault current limiting instant in two winding directions were dependent on the fault angles. It was confirmed from experiment that the fault current limiting instant was getting faster and the magnitude of fault current at the initial fault time was getting higher for higher fault angle.

• Health Policy and Management
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• v.9 no.2
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• pp.118-138
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• 1999

This study presents the variations on drug utilization for outpatients' URI, gastritis. and hypertension by the type of hospital- tertiary hospital. general hospital. hospital. clinic. It investigated drug expenses. daily drug expenses. days of medication. the highest price of the drugs used. and the number of the different drugs used for each disease and type of hospital. This study also performed analysis to see how much the variations of variables related to drug use affect the variations of drug expenses. The dependent variable was drug expenses and the independent variables were days of medication. the average price of the drugs used. and the number of the different drugs used. Analysis of the drug utilization was performed on NFMI(National Federation of Medical Insurance) 1994 medical expense claim data. Patients with secondary diseases were excluded. In this study. 379 patients with URI, 386 patients with gastritis. 1.257 patients with hypertension were included. It was founded that there were large variation on drug utilization between the types of hospital for same diseases. Days of medication were longest in tertiary hospitals and shortest in hospitals or clinics. Clinics showed the lowest daily drug expenses in all of the diseases investigated. Daily drug expenses were highest in general hospitals or hospitals. which also tended to use drugs of higher price than other types of hospital. General hospitals and hospitals had larger variations in daily drug expenses and the highest price of drugs. It suggested that drug might be utilized overly in general hospitals and hospitals and some other factors might influence on drug utilization in these hospitals. It was found that the variations of drug expenses were affected by the variations of drug price and days of medication rather than the number of the different drugs. Then the strategy to reduce the variations of drug utilization and to improve the quality of drug utilization should focus on the drug price and days of medication. Further study is needed to assess the quality as well as the variation of drug utilization and to show the factors which affect them.

• Imaging Science in Dentistry
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• v.53 no.1
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• pp.77-82
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• 2023

Purpose: This study evaluated anatomical variations in the root canals of the lower premolars and molars in a Brazilian sub-population using cone-beam computed tomography (CBCT). Materials and Methods: In total, 121 CBCT images of patients were selected from a database. All images contained lower first and second premolars and molars on both sides of the arch, fully developed roots, and no treatment, resorption, or calcifications. In each image, the root canals of the lower premolars and molars were evaluated according to the Vertucci classification in On-Demand 3D software in the multiplanar reconstruction with dynamic navigation. Twenty-five percent of the images were re-assessed to analyze intraobserver confidence with the kappa test. Data were statistically evaluated with linear regression to evaluate the correlations of anatomic variations with age and sex, and the Wilcoxon test to analyze the laterality of variations, with a significance level of 5%. Results: The intraobserver agreement (0.94) was excellent. In general, the root canals of lower premolars and molars showed a higher prevalence of type I than other Vertucci classification types, followed by type V in premolars and type II in molars. When the molar roots were evaluated separately, type II was more frequent in mesial roots and type I in distal roots. Although age showed no correlations with the results, sex and laterality showed correlations with tooth 45 and the lower second premolars, respectively. Conclusion: The lower premolars and molars of a Brazilian sub-population showed a wide range of root canal anatomic variations.