• Journal of the Korean Operations Research and Management Science Society
• /
• v.16 no.2
• /
• pp.13-35
• /
• 1991

The purpose of this study is to develop an efficient exact algorithm for the problem of scheduling n in dependent jobs on m unequal parallel processors to minimize makespan. Efficient solutions are already known for the preemptive case. But for the non-preemptive case, this problem belongs to a set of strong NP-complete problems. Hence, it is unlikely that the polynomial time algorithm can be found. This is the reason why most investigations have bben directed toward the fast approximate algorithms and the worst-case analysis of algorithms. Recently, great advances have been made in mathematical theories regarding Lagrangean relaxation and the subgradient optimization procedure which updates the Lagrangean multipliers. By combining and the subgradient optimization procedure which updates the Lagrangean multipliers. By combining these mathematical tools with branch-and-bound procedures, these have been some successes in constructing pseudo-polynomial time algorithms for solving previously unsolved NP-complete problems. This study applied similar methodologies to the unequal parallel processor problem to find the efficient exact algorithm.

• Journal of Korean Dental Science
• /
• v.10 no.2
• /
• pp.74-81
• /
• 2017

This report describes two cases of complete arch implant-supported restorations. The first patient had seven dental implants in each arch with monolithic zirconia frameworks. At four weeks' follow-up, the one-piece maxillary framework was fractured, which was re-designed and re-fabricated using laser-sintered cobalt-chrome alloy. The second patient had four implants in the mandible only. A mandibular monolithic zirconia framework and a maxillary conventional complete denture were fabricated and delivered. At five years' follow-up, the patient reported no significant discomfort. Careful consideration and monitoring of the status of antagonistic arches and stress distribution on zirconia frameworks were suggested for complete arch implant-supported fixed restorations.

• Journal of KSNVE
• /
• v.4 no.3
• /
• pp.283-295
• /
• 1994

This work presents the experimental and finite element analysis results for the free vibration of 4 edges clamped, isotropic square plates with 2 collinear circular holes. Natural frequencies of finite element analysis are obtained for the complete square plate, the square plates with a central circular hole and the square plates with 2 collinear circulare holes. And natural frequencies are experimentally measured for the complete square plate, the square plate with a central circular hole(d = 150 mm) and the square plates with 2 collinear circular holes. Agreement between experimental and FEM results is excellent. Mode shapes in special case are presented. The conclusions of the study are as follows. There is little variation of nondimensional frequency parameters for the first six mode when the aspect ratio of circular hole is less than 1/6 in the isotropic square plates with 2 collinear circular holes. And the first nondimensional frequency parameter doesn't vary as the aspect ratio of circular hole increase.

• Journal of the Korean Statistical Society
• /
• v.18 no.1
• /
• pp.13-25
• /
• 1989

This paper suggests a classification rule with unequal covariance matrices when a patterned incomplete data are involved in the discriminant analysis. This is an extension of Geisser's (1966) result to the case of missing observations. For the calssificaiton rule, we introduce an algorithm which contains data augmentation step and Monte Carlo integration step and show that the algorithm yields a consistant estimator of true classification probability. The proposed method is compared to the complete observation vector method through a Monte Carlo study. The results show that the suggested method, in general, performs better than the complete observation vector method which ignores those vectors of observation with one or more missing values from the analysis. The results also verify the consistency of the algorithm.

• Tribology and Lubricants
• /
• v.35 no.4
• /
• pp.229-236
• /
• 2019

This study investigates the stress singularity that occurs at the contact edge of three bodies in a frictional complete contact. We use the asymptotic analysis method, wherein we constitute an eigenvalue problem and observe the eigenvalue behavior, which we use to obtain the order of the stress singularity. For the present geometry of three bodies in contact, a contact between a cracked indenter and half plane is considered. This is a typical geometry of the PCMI problem of a nuclear fuel rod. Thus, this paper, specifically presents the characteristics of the PCMI problem from the perspective of stress singularity. Consequently, it is noted that the behavior of the stress singularity varies with the difference in the crack angle, coefficient of friction, and material dissimilarity, as is observed in a frictional complete contact of two bodies. In addition, we find that the stress singularity changes essentially linearly with respect to the coefficient of friction, regardless of the variation in the crack angle and material dissimilarity. Concurrently, we find the order of singularity to be 0.5 at a certain coefficient of friction, irrespective of the crack angle, which we also observe in the crack problem of a homogeneous and isotropic body. The order of singularity can also exceed 0.5 in the frictional complete contact problem of three bodies. This implies that the propensity for failure when three bodies are in frictional complete contact can be even worse than that in case of a failure induced by a crack.

• Asian Pacific Journal of Cancer Prevention
• /
• v.17 no.10
• /
• pp.4567-4575
• /
• 2016

A number of studies have evidenced the effect of modifiable lifestyle factors such as diet, breastfeeding and nutritional status on breast cancer risk. However, none have addressed the missing data problem in nutritional epidemiologic research in South America. Missing data is a frequent problem in breast cancer studies and epidemiological settings in general. Estimates of effect obtained from these studies may be biased, if no appropriate method for handling missing data is applied. We performed Multiple Imputation for missing values on covariates in a breast cancer case-control study of $C{\acute{o}}rdoba$ (Argentina) to optimize risk estimates. Data was obtained from a breast cancer case control study from 2008 to 2015 (318 cases, 526 controls). Complete case analysis and multiple imputation using chained equations were the methods applied to estimate the effects of a Traditional dietary pattern and other recognized factors associated with breast cancer. Physical activity and socioeconomic status were imputed. Logistic regression models were performed. When complete case analysis was performed only 31% of women were considered. Although a positive association of Traditional dietary pattern and breast cancer was observed from both approaches (complete case analysis OR=1.3, 95%CI=1.0-1.7; multiple imputation OR=1.4, 95%CI=1.2-1.7), effects of other covariates, like BMI and breastfeeding, were only identified when multiple imputation was considered. A Traditional dietary pattern, BMI and breastfeeding are associated with the occurrence of breast cancer in this Argentinean population when multiple imputation is appropriately performed. Multiple Imputation is suggested in Latin America's epidemiologic studies to optimize effect estimates in the future.

• Asian-Australasian Journal of Animal Sciences
• /
• v.8 no.6
• /
• pp.651-655
• /
• 1995

A simulation study on detection of linkage between genetic markers and QTL in backcross design was conducted. The effects of various sample sizes and the degree of QTL dominance on detention of linkage were examined by using a simple regression analysis. The results indicated that as sample size increased, the standard error of the estimated slope became smaller. When the dominance effect of QTL was complete, the estimated slope tended to be negative but was statistically not significant at all with type I error of greater than 50%. With complete linkage between genetic Marker and QTL, the estimated intercept value was smallest but the estimated slope was largest as expected. In most cases with various degree of dominance and sample sizes, when the actual recombination rate became larger, greater values were obtained for the slope except in the case of complete dominance of QTL.

• Annals of Pediatric Endocrinology and Metabolism
• /
• v.23 no.4
• /
• pp.220-225
• /
• 2018

Androgen insensitivity syndrome (AIS) is a rare genetic disease caused by various abnormalities in the androgen receptor (AR). The AR is an essential steroid hormone receptor that plays a critical role in male sexual differentiation and development and preservation of the male phenotype. Mutations in the AR gene on the X chromosome cause malfunction of the AR so that a 46,XY karyotype male has some physical characteristics of a woman or a full female phenotype. Depending on the phenotype, AIS can be classified as complete, partial or mild. Here, we report 2 cases of complete AIS in young children who showed complete sex reversal from male to female as a result of AR mutations. They had palpable inguinal masses and normal female external genitalia, a blind-end vagina and absent $M{\ddot{u}}llerian$ duct derivatives. They were both 46,XY karyotype and AR gene analysis demonstrated pathologic mutations in both. Because AIS is inherited in an X-linked recessive manner, we performed genetic analysis of the female family members of each patient and found the same mutation in the mothers of both patients and in the female sibling of case 2. Gonadectomy was performed in both patients to avoid the risk of malignancy in the undescended testicles, and estrogen replacement therapy is planned for their adolescence. Individuals with complete AIS are usually raised as females and need appropriate care.

• Korea Journal of Hospital Management
• /
• v.26 no.3
• /
• pp.43-55
• /
• 2021

Purposes: The purpose of this study is to confirm the effect of mother's nationality on screening rates for infants and children health screening. We intend to find out if there is a difference in health level between infants of multicultural families and infants of domestic families, and contribute to policies to enhance future national health levels by providing information on them. Methodology: Data for those who received the first infant and children health screening between 2012 and 2018 were obtained from the National Health Insurance Service(NHIS) DB. Frequency analysis, chi-square test and logistic regression analysis were performed with the SAS 9.4 program, and the case where all the 1st to 3rd checkups were completed was defined as type I, and the case of all the 1st to 7th checkups completed, type II. Findings: Complete screening rates for type I and type II were 45.8% and 20.0%, respectively. Especially, complete screening rate of infants whose mothers nationality is foreign is only 3-4th of that of domestic mothers, and it also differed according to nationality. Practical Implications: The difference in the screening rate according to the mother's nationality is likely to lead to a health gap between multicultural families and domestic families. It is necessary to promote and encourage proper monitoring and health management through continuous health screening for infants and children.

• The Journal of Internal Korean Medicine
• /
• v.28 no.4
• /
• pp.872-885
• /
• 2007

Objective : Stroke is one of the most common causes of death in Korea. This study was done to evaluate the association of complete blood count (CBC) with the risk of hemorrhagic stroke and ischemic stroke. Methods : In 217-case patients with ischemic stroke or hemorrhagic stroke and 146 healthy control subjects without stroke, hypertension, diabetes mellitus, hyperlipidemia, or ischemic heart disease and 160 controls without ischemic stroke or hemorrhagic stroke, we tested and compared white blood cell count (WBC), red blood cell count (RBC), hemoglobin (Hgb), hematocrit (Hct) and platelet. These data were statically analyzed by general linear models and binary logistic regression analysis to get each adjusted odds ratio. Results :The level of WBC was significantly higher in all cases. The level of RBC, Hct and Hgb was significantly lower in patients of ischemic stroke. The level of platelet was significantly higher in patients of ischemic stroke. Conclusion : These results suggest high WBC may be a risk factor of hemorrhagic stroke and ischemic stroke and low RBC, low Hct, low Hgb and high platelet may be risk factors of ischemic stroke in Koreans.