• Tunnel and Underground Space
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• v.23 no.5
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• pp.383-391
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• 2013

A number of true triaxial tests on rock samples have been conducted since the late 1960 and their results strongly suggest that the intermediate principal stress has a considerable effect on rock strength. Based on these experimental evidence, various 3-D rock failure criteria accounting for the effect of the intermediate principal stress have been proposed. Most of the 3-D failure criteria, however, are focused on the phenomenological description of the rock strength from the true triaxial tests, so that the associated strength parameters have little physical meaning. In order to confirm the likelihood that the intermediate principal stress dependency of rock strength is related to the presence of weak planes and their distribution to the preferred orientation, true triaxial tests are simulated with the transversely isotropic rock model. The conventional Mohr-Coulomb criterion is extended to its anisotropic version by incorporating the concept of microstructure tensor. With the anisotropic Mohr-Coulomb criterion, the critical plane approach is applied to calculate the strength of the transversely isotropic rock model and the orientation of the fracture plane. This investigation hints that the spatial distribution of microstructural planes with respect to the principal stress triad is closely related to the intermediate principal stress dependency of rock strength.

• Journal of Korea Water Resources Association
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• v.32 no.4
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• pp.403-415
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• 1999

This study is to derive the rainfall intensity formula based on the representative probability distribution in Korea. The 11 probability distributions which has been widely used in hydrologic frequency analysis are applied to the annual maximum rainfall. The parameters of each probability distribution are estimated by method of moments, maximum likelihood method and method of probability weighted moments. Four tests such as $x^2$-test, Kolmogorv-Smirnov test, difference test and modified difference test are used to determine the goodness of fit of the distributions. The homogeneous tests (Mann-Whitney U test, Kruskal-Wallis one-way analysis of variance of nonparametric test) are applied to find the stations with rainfall homogeneity. The results of homogeneous tests show that there is no representative appropriate distribution for the whole duration in Korea. The whole region could be divided into five zones for 12-durations. The representative probability distribution of each divided zone for 12-durations was determined. The GEV distribution for I,II,V zones and the 3-parameter Weibull distribution for III,IV zones were determined as the representative probability distribution. The rainfall were obtained from representative probability distribution for the selected return periods. Rainfall intensity formula was determined by linearization technique for the rainfall.

• Health Policy and Management
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• v.24 no.4
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• pp.349-356
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• 2014

Background: This study aimed to explore factors associated with the non-use of beneficiaries of long-term care insurance services for the elderly in Jeollanam-do Province by analyzing a dataset obtained from National Health Insurance Service. Methods: The study sample consists of 1,663 individuals who were evaluated as eligible for long-term care insurance services in Jeollanam-do Province during the period of July 1, 2008 through June 30, 2009. As a dependent variable, the non-use of the service was defined as one when a beneficiary had used it once or more times during one year after he or she was evaluated as eligible and as zero otherwise. A proportion analysis was conducted to describe characteristics of study sample. Chi-square tests were used to compare general characteristics between beneficiaries who had used the services and those who had not used them. Multiple logistic regressions were performed by three models including additional sets of explanatory variables such as socio-demographic characteristics, health conditions, and economic status. Results: Main results are summarized as follows. The proportion of beneficiaries who had not used the service was 14.5% of all beneficiaries. According to the results from the model using all explanatory variables, the factors associated with the non-use of the services were residence location, dwelling place, type of desired service, level of care needs, and instrumental activities of daily life limitations. Conclusion: In particular, regarding the type of desired service, the cash benefit showed a high likelihood of the non-use of the service; it had an odds ratio (OR) of 50.212 (95% confidence interval [CI], 24.00-105.04) compared with home service. In case of dwelling place, a hospital showed also a high likelihood of the non-use with an OR of 20.71 (95% CI, 10.12-42.44) compared with home.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.6
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• pp.1908-1918
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• 1991

Fatigue tests have been carried out to measure the degradation of the residual strength and the fatigue life in carbon/epoxy (0/45/90/-45)$_{2s}$ composite materials. Theoretical predictions of residual strength and fatigue life were compared with experimental results. Distribution characteristics were studied using the probability of failure based on the cumulative distribution function and median rand. The static ultimate strength of carbon/epoxy composites used herein is observed to be relatively higher than that of existing similar composites ; while fatigue life is shorter due to the brittleness of matrix. The fatigue life obtained in these experiments is shorter than that estimated by residual strength degradation model when the stress level above 0.6 For the stress level of 0.6, the experimental value was abruptly increased. The cumulative distribution function for the static ultimate strength is well correlated to that for the strength converted from the measured fatigue life. Also, the predicted distribution of residual strength shows good agreement with the experimental results. Therefore, it is proven that the residual strength degradation model is reasonable.e.

• Molecules and Cells
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• v.23 no.1
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• pp.39-48
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• 2007

Charcot-Marie-Tooth (CMT) disease and hereditary neuropathy with liability to pressure palsies (HNPP) are frequent forms of genetically heterogeneous peripheral neuropathies. Reciprocal unequal crossover between flanking CMT1A-REPs on chromosome 17p11.2-p12 is a major cause of CMT type 1A (CMT1A) and HNPP. The importance of a sensitive and rapid method for identifying the CMT1A duplication and HNPP deletion is being emphasized. In the present study, we established a molecular diagnostic method for the CMT1A duplication and HNPP deletion based on hexaplex PCR of 6 microsatellite markers (D17S921, D17S9B, D17S9A, D17S918, D17S4A and D17S2230). The method is highly time-, cost- and sample-saving because the six markers are amplified by a single PCR reaction and resolved with a single capillary in 3 h. Several statistical and forensic estimates indicated that most of these markers are likely to be useful for diagnosing the peripheral neuropathies. Reproducibility, as determined by concordance between independent tests, was estimated to be 100%. The likelihood that genotypes of all six markers are homozygous in randomly selected individuals was calculated to be $1.6{\times}10^{-4}$, which indicates that the statistical error rate for this diagnosis of HNPP deletion is only 0.016%.

• Proceedings of the KAIS Fall Conference
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• 2012.05a
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• pp.22-24
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• 2012

The tools that classify the severity of patients based on the prediction of mortality include APACHE, SAPS, and MPM. Theses tools rely crucially on the evaluation of patients' general clinical status on the first date of their admission to ICU. Nursing activities are one of the most crucial factors influencing on the quality of treatment that patients receive and one of the contributing factors for their prognosis and safety. The purpose of this study was to identify the goodness-of-fit of CPSCS of critical patient severity classification system(CPSCS) and Glasgow coma scale(GCS) and the clinical usefulness of its death rate prediction. Data were collected from the medical records of 187 neurological patients who were admitted to the ICU of C University Hospital. The data were analyzed through $x^2$ test, t-test, Mann-Whitney, Kruskal-Wallis, goodness-of-fit test, and ROC curve. In accordance with patients' general and clinical characteristics, patient mortality turned out to be statistically different depending on ICU stay, endotracheal intubation, central venous catheter, and severity by CPSCS. Homer-Lemeshow goodness-of-fit tests were CPSCS and GCS and the results of the discrimination test using the ROC curve were $CPSCS_0$, .734, $GCS_0$,.583, $CPSCS_{24}$,.734, $GCS_{24}$, .612, $CPSCS_{48}$,.591, $GCS_{48}$,.646, $CPSCS_{72}$,.622, and $GCS_{72}$,.623. Logistic regression analysis showed that each point on the CPSCS score signifies1.034 higher likelihood of dying. Applied to neurologically ill patients, early CPSCS scores can be regarded as a useful tool.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.2
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• pp.225-230
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• 2017

To generate mechanical movements in one-shot devices such as missiles and space launch vehicles, pyrotechnic mechanical device(PMD) such as pin pullers using pyrotechnic charge has been widely used. Reliability prediction of pin pullers is crucial to successfully execute target missions for the one-shot devices. Because the pin pullers require destructive tests to evaluate their reliability, one would need about 3,000 samples of success to guarantee a reliability of 99.9 % with a confidence level of 95 %. This paper suggests the application of a probit model using the charge amount as a functional parameter for estimation of functional reliability of pin puller. To guarantee target reliability, we propose estimation methods of the lower bound of functional reliability by applying the probit model. Given lower bound of functional reliability, we quantitatively show that the optimum amount of charge increases as the number of samples decreases. Along with a variety of simulations the validity of our new model via real test results is confirmed.

• Clinical and Experimental Pediatrics
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• v.59 no.2
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• pp.80-90
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• 2016

Purpose: Studies have been conducted to identify predictive factors of resistance to intravenous immunoglobulin (IVIG) for Kawasaki disease (KD). However, the results are conflicting. This study aimed to identify laboratory factors predictive of resistance to high-dose IVIG for KD by performing meta-analysis of available studies using statistical techniques. Methods: All relevant scientific publications from 2006 to 2014 were identified through PubMed searches. For studies in English on KD and IVIG resistance, predictive factors were included. A meta-analysis was performed that calculated the effect size of various laboratory parameters as predictive factors for IVIG-resistant KD. Results: Twelve studies comprising 2,745 patients were included. Meta-analysis demonstrated significant effect sizes for several laboratory parameters: polymorphonuclear leukocytes (PMNs) 0.698 (95% confidence interval [CI], 0.469-0.926), C-reactive protein (CRP) 0.375 (95% CI, 0.086-0.663), pro-brain natriuretic peptide (pro-BNP) 0.561 (95% CI, 0.261-0.861), total bilirubin 0.859 (95% CI, 0.582-1.136), alanine aminotransferase (AST) 0.503 (95% CI, 0.313-0.693), aspartate aminotransferase (ALT) 0.436 (95% CI, 0.275-0.597), albumin 0.427 (95% CI, -0.657 to -0.198), and sodium 0.604 (95% CI, -0.839 to -0.370). Particularly, total bilirubin, PMN, sodium, pro-BNP, and AST, in descending numerical order, demonstrated more than a medium effect size. Conclusion: Based on the results of this study, laboratory predictive factors for IVIG-resistant KD included higher total bilirubin, PMN, pro-BNP, AST, ALT, and CRP, and lower sodium and albumin. The presence of several of these predictive factors should alert clinicians to the increased likelihood that the patient may not respond adequately to initial IVIG therapy.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.5
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• pp.527-531
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• 2008

For statistical modeling, the model parameters are usually estimated by maximizing a probability measure, such as the likelihood or the posterior. In contrast, a variational Bayesian method treats the parameters of a model as probability distributions and computes optimal distributions for them rather than values. It has been shown that this approach effectively avoids the overfitting problem, which is common with other parameter optimization methods. This paper applies a variational Bayesian technique to surface fitting for height field data. Then, we propose point cloud denoising based on the basic surface fitting technique. Validation experiments and further tests with scan data verify the robustness of the proposed method.

• The Korean Journal of Applied Statistics
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• v.25 no.1
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• pp.55-66
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• 2012

Option pricing models using L$\acute{e}$evy processes are suggested as an alternative to the Black-Scholes model since empirical studies showed that the Black-Sholes model could not reflect the movement of underlying assets. In this paper, we investigate whether the Variance Gamma model can reflect the movement of underlying assets in the Korean stock market better than the Black-Scholes model. For this purpose, we estimate parameters and perform likelihood ratio tests using KOSPI 200 data based on the density for the log return and the option pricing formula proposed in Madan et al. (1998). We also calculate some statistics to compare the models and examine if the volatility smile is corrected through regression analysis. The results show that the option price estimated under the Variance Gamma process is closer to the market price than the Black-Scholes price; however, the Variance Gamma model still cannot solve the volatility smile phenomenon.