• Journal of the Korean Statistical Society
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• v.32 no.2
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• pp.121-150
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• 2003

The National Health Interview Survey (NHIS) is one of the surveys used to assess the health status of the US population. One indicator of the nation's health is the total number of doctor visits made by the household members in the past year, There is a substantial nonresponse among the sampled households, and the main issue we address here is that the nonrespones mechanism should not be ignored because respondents and nonrespondents differ. It is standard practice to summarize the number of doctor visits by the binary variable of no doctor visit versus at least one doctor visit by a household for each of the fifty states and the District of Columbia. We consider a nonignorable nonresponse model that expresses uncertainty about ignorability through the ratio of odds of a household doctor visit among respondents to the odds of doctor visit among all households. This is a hierarchical model in which a nonignorable nonresponse model is centered on an ignorable nonresponse model. Another feature of this model is that it permits us to "borrow strength" across states as in small area estimation; this helps because some of the parameters are weakly identified. However, for simplicity we assume that the hyperparameters are fixed but unknown, and these hyperparameters are estimated by the EM algorithm; thereby making our method Bayes empirical Bayes. Our main result is that for some of the states the nonresponse mechanism can be considered non-ignorable, and that 95% credible intervals of the probability of a household doctor visit and the probability that a household responds shed important light on the NHIS.

• Journal of Preventive Medicine and Public Health
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• v.39 no.5
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• pp.433-437
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• 2006

Objectives: The aim of this study is to develop a methodology for estimating a nationwide statistic for hernia operations with using the claim database of the Korea Health Insurance Cooperation (KHIC). Methods: According to the insurance claim procedures, the claim database was divided into the electronic data interchange database (EDI_DB) and the sheet database (Paper_DB). Although the EDI_DB has operation and management codes showing the facts and kinds of operations, the Paper_DB doesn't. Using the hernia matched management code in the EDI_DB, the cases of hernia surgery were extracted. For drawing the potential cases from the Paper_DB, which doesn't have the code, the predictive model was developed using the data mining technique called SEMMA. The claim sheets of the cases that showed a predictive probability of an operation over the threshold, as was decided by the ROC curve, were identified in order to get the positive predictive value as an index of usefulness for the predictive model. Results: Of the claim databases in 2004, 14,386 cases had hernia related management codes with using the EDI system. For fitting the models with applying the data mining technique, logistic regression was chosen rather than the neural network method or the decision tree method. From the Paper_DB, 1,019 cases were extracted as potential cases. Direct review of the sheets of the extracted cases showed that the positive predictive value was 95.3%. Conclusions: The results suggested that applying the data mining technique to the claim database in the KHIC for estimating the nationwide surgical statistics would be useful from the aspect of execution and cost-effectiveness.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.4
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• pp.368-376
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• 2015

This paper is the study on the establishment of design model to improve design efficiency using modified weight estimation equation on the initial design stage for development of a helicopter. The methodology to extract coefficients of the weight estimation equation was proposed through the influence investigation for the weight of components and the parameter study and sensitivity analysis for design variables such as the rotor disk loading, the number of blade and the aspect ratio of blade were also performed. As a result of study, the relation of parameters and degree of sensitivity of parameters on helicopter design are considerable points for optimization of helicopter characteristics, and it is necessary for designer to consider the complex relation of main parameters.

• The Journal of the Korea Contents Association
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• v.9 no.8
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• pp.147-157
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• 2009

Recently, there has been continued research on UCP from the development effort estimation method to a software development project applying object oriented development methodology. Current research proposes a linear model estimating the developmenteffort by multiplying a constant to AUCP which applies technical and environmental factors. However, the fact that a non-linear regression model is more appropriate as the software size increases, the development period increases exponentially. In addition, in the UCP calculation process the occurrence of FP errors due to the application of TCF and EF, it is unrealistic to estimate the size with AUCP. This paper presents the issue of current research based on UCP without considering problems of the research, for example, TCF and EF and expresses the models (linear, logarithmic, polynomial, power and exponential type) estimating the development effort directly from UUCP. Consequently, the exponential model within non-linear models exhibit more accurate results than the current linear model. Therefore, after calculating the UUCP of the developing software system, using the proposed model to estimate the development effort, it is possible to estimate the direct cost required in development.

• The KIPS Transactions:PartB
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• v.12B no.1 s.97
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• pp.17-24
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• 2005

In this paper, we will show that a control search methodology is a alternative method of a sequential search which is difficult in finding books for arrangement at library or a bookstore when books are out of place. To solve the problem of the sequential search, we apply a edge operator and the Hough Transform to boundary of a taken photograph image book. We generate histogram by a projected image from boundary range of selected books and select title areas from this and possible areas which are a character number of title, authors, a publishing company and an array sequence. Finally, we can select the final possible area of a book location by a curve fitting and a regression line extraction, and show utility through experiment.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.6
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• pp.881-887
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• 2011

In this paper, age exploration of ${\bigcirc}{\bigcirc}$ anti-ship missiles which were deployed on RoKN ships were analysed using parametric estimation method. Additionally, Life distribution and failure pattern of ${\bigcirc}{\bigcirc}$ anti-ship missile were analysed by using field data such as collected inspection, fail, maintenance record for 6 years. Storage failure and MTBF of missile and components were analysed by using reliability analysis s/w Weibull++ v7. The results were compared with maintenance policy including periodic inspection and MTBF which were analysed during development phase. Finally, the suggested methodology using field data analysis of oo anti-ship missile will be applied on re-estabilishment of maintenance policy of ${\bigcirc}{\bigcirc}$ anti-ship missile for TLCSM(Total Life Cost System Management) effectively.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2B
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• pp.147-154
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• 2011

Physical habitat assessment models based on Instream Flow Incremental Methodology have been developed as a decision making tool to estimate appropriate discharge for environmental flow and water use management. These models, however, require extensive knowledge on various academic disciplines, complicated input data, and empirical data. We propose a Simplified Habitat (SIMHAB) simulation model for the estimation of physical structure of fish habitat and environmental flow at the planning stage. SIMHAB is applied to a river system for which physical and ecological data are available, and its applicability is investigated. Simulated results appeared to be similar to field survey data and those of such models as PHABSIM and River2D. However, SIMHAB requires much less input data. As such, the proposed model, SIMHAB can easily be applicable to river restoration projects including designing of physical habitat, estimation of environmental flow, and water resource management.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.9
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• pp.740-753
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• 2008

The conventional Split Hopkinson Pressure Bar (C-SHPB) technique with aluminum pressure bars to achieve a closer impedance match between the pressure bars and the specimen materials such as hot temperature degraded POM (Poly Oxy Methylene) and PP (Poly Propylene) to obtain more distinguishable experimental signals is used to obtain a dynamic behavior of material deformation under a high strain rate loading condition. An experimental modification with Pulse shaper is introduced to reduce the nonequilibrium on the dynamic material response during a short test period to increase the rise time of the incident pulse for two polymeric materials. For the dynamic stress strain curve obtained from SHPB experiment under high strain rate, the Johnson-Cook model is applied as a constitutive equation, and we verify the applicability of this constitutive equation to the probabilistic reliability estimation method. The methodology to estimate the reliability using the probabilistic method such as the FORM and the SORM has been proposed, after compose the limit state function using Johnson-Cook model. It is found that the failure probability estimated by using the SORM is more reliable than those of the FORM, and the failure probability increases with the increase of applied stress. Moreover, it is noted that the parameters of Johnson-Cook model such as A and n, and applied stress affect the failure probability more than the other random variables according to the sensitivity analysis.

• Nuclear Engineering and Technology
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• v.44 no.7
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• pp.791-798
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• 2012

Since standardized fracture test specimens cannot be easily extracted from in-service components, several alternative fracture toughness test methods have been proposed to characterize the deformation and fracture resistance of materials. One of the more promising alternatives is the local approach employing the SP(Small Punch) testing technique. However, this process has several limitations such as a lack of anisotropic yield potential and tediousness in the damage parameter calibration process. The present paper investigates estimation of ductile fracture resistance(J-R) curve by FE(Finite Element) analyses using an anisotropic damage model and enhanced calibration procedure. In this context, specific tensile tests to quantify plastic strain ratios were carried out and SP test data were obtained from the previous research. Also, damage parameters constituting the Gurson-Tvergaard-Needleman model in conjunction with Hill's 48 yield criterion were calibrated for a typical nuclear reactor material through a genetic algorithm. Finally, the J-R curve of a standard compact tension specimen was predicted by further detailed FE analyses employing the calibrated damage parameters. It showed a lower fracture resistance of the specimen material than that based on the isotropic yield criterion. Therefore, a more realistic J-R curve of a reactor material can be obtained effectively from the proposed methodology by taking into account a reduced load-carrying capacity due to anisotropy.

• Health Policy and Management
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• v.9 no.2
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• pp.95-117
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• 1999

The purposes of the study was to analysis the factors on the physicians' indemnity experience and indemnity on malpractice. Data was collected from mail interview for the physicians from August, to October in 1996. Questions were asked to the physician who selected with random sample(n=8.338) about the opinion of malpractice insurance. experience that he(she) have requested the indemnity from patience. context of experienced indemnity and demographic characteristics of physician and patience. Response rate is 37.5%(n=3,124). This study was analyzed in two levels' the first. influential factors on whether physician has experience of indemnity and the second. influential factors of indemnity among physicians who had experienced the indemnity. The major findings were as follows : 1. Logistic regression on whether physicians had experience of indemnity request was conducted. And it indicated that statistically meaningful variables of model 1 (about all physicians) were department of surgery, physicians who have intention of insurance fee, physician age and income, physicians who owned the hospitals and statistically meaningful variables of model 11 (about physicians who owned the hospital) were department of surgery and internal treatment. 2. Multiple regression on the influential factors on indemnity was conducted. And it showed that statistically meaningful variables in model 1 were method of malpractice quarrel(physician association), whether physician had malpractice, whether suit succeeded, physician age, average practice time and income and whether physician owned the hospital and statistically meaningful variables of model 11 were whether physician had malpractice, number of outpatient, number of beds. As the conclusion, the thesis was examined about the variables related with experience of indemnity and cost of malpractice. But in order to prevent malpractice and promote medical quality, the reasonable system to solve a malpractice have to settle and cost estimation on malpractice is essential. Therefore an advanced research is progressed with methodology to decide the indemnity bases.