• Transactions of the Korean Society of Mechanical Engineers
• /
• v.19 no.6
• /
• pp.1451-1459
• /
• 1995

The objective of this paper is to evaluate the material properties of SA312 TP316 and SA312 TP304 stainless steels and their associated welds manufactured for safety injection system of Yonggwang 3,4 nuclear generating stations. A total of 62 tensile tests and 46 fracture toughness tests were conducted and the effects of various parameters such as pipe size, crack plane orientation, tests were conducted and the effects of various parameters such as pipe size, crack plane orientation, test temperature, welding on material properties were discussed. Test results show that the effect of test temperature on fracture toughness was significant while the effects of pipe size and crack plane orientation on fracture toughness were negligible. Fracture toughness of the weld metal was in general higher than that of the base metal.

• Journal of the Korean Wood Science and Technology
• /
• v.24 no.3
• /
• pp.65-71
• /
• 1996

In the design of wood structures, the consideration of the dynamic load effect has been increased. Generally, damping ratio is presented as the method of considering dynamic load effect. So, the relationship between joint type and damping ratio was investigated. It has been known that the joint extremely damp the dynamic load in wood structures. Static test was performed to determine the effects of nail size and friction area on joint strength and stiffness. Joint strength and stiffness were increased with nail size. However, the static properties of joint was not affected by friction area. Cyclic test was performed to determine the effects of nail size, friction area and load magnitude on damping ratio, Damping ratio was affected by all factors. Increasing the width of the bottom plate was suggested as the most adequate method to increase the damping ratio without the reduction of the static properties of the structures.

• Journal of the Korean Institute of Navigation
• /
• v.5 no.1
• /
• pp.25-35
• /
• 1981

Since 1960 tankers and bulk carriers have rapidly increased in size up to 500, 000 dwt. in operating as main system of transportation for the international trade at sea, and studies are doing carried out by various groups with a view to increasing the size still further. However, the service speed of these ships has remained almost constant, and steering devices of them have nearly not changed, comparing with regular size of a dry cargo ship. This creats the dituation where stopping distance and advance are proportionally longer for larger ships. In case of collision at sea, these vessels have been arised some serious casualties, such as sinking, fire and oil pollution. This paper analyzers a study for the handling of super huge vessels to avoid collision at sea, basing on the results of the crash astern test and turning test of them.

• Journal of the Korean Data and Information Science Society
• /
• v.28 no.6
• /
• pp.1557-1564
• /
• 2017

We take genomic sequences of high-dimensional low sample size (HDLSS) without ordering of response categories into account. When constructing an appropriate test statistics in this model, the classical multivariate analysis of variance (MANOVA) approach might not be useful owing to very large number of parameters and very small sample size. For these reasons, we present a pseudo marginal model based upon the Gini-Simpson index estimated via Bayesian approach. In view of small sample size, we consider the permutation distribution by every possible n! (equally likely) permutation of the joined sample observations across G groups of (sizes $n_1,{\ldots}n_G$). We simulate data and apply false discovery rate (FDR) and positive false discovery rate (pFDR) with associated proposed test statistics to the data. And we also analyze real SARS data and compute FDR and pFDR. FDR and pFDR procedure along with the associated test statistics for each gene control the FDR and pFDR respectively at any level ${\alpha}$ for the set of p-values by using the exact conditional permutation theory.

• Journal of Fashion Business
• /
• v.4 no.3
• /
• pp.103-114
• /
• 2000

The purpose of this study was to test the discriminant analysis model of Quick Response system and to examine the detailed relationship between each discriminant factor and Quick Response adoption. In this discriminant analysis model of Quick Response system, firm size, strategic type, product category, fashion trend, selling time and the Quick Response benefits were included as discriminant factors. Onehundred and two subjects were randomly selected for the survey study and discriminant analysis, descriptive analysis, t-test, and x square test were used for the data analysis. The results of this study were: 1. Wilks Lambda and F value support the discriminant analysis model that, taken together firm size, strategic type, product category, fashion trend, selling time and the Quick Response benefits significantly help to explain Quick Response adoption. 2. The importance of discriminant ability was, in order, firm size, the Quick Response benefits, women's wear, fashion trend, analyzer, selling time, reactor, defender and men's wear. 3. The discriminant function had the high hit ratio, so this can be well used for the classification of Quick Response adoption/nonadoption.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2003.10a
• /
• pp.191-194
• /
• 2003

The purpose of this paper was to derive soil-water characteristic curve equation for unsaturated soil. To this end, a series of suction measured test was conducted on the selected 4 kinds of soil which is located in Korea, used the modified pressure plate apparatus. From the test results, it was proved that characteristic curve changes according to grain size distribution, size of void and fine grained soil contents. Residual degree of saturation(Sr) was decreased with void ratio and changed with fine grained soil contents, parameter ${\lambda}$ and hr was increased with void ratio. Soil-water characteristic curve equation based on the test result was suggested by void ratio or grain size distribution.

• Journal of Korean Society for Atmospheric Environment
• /
• v.22 no.E1
• /
• pp.27-34
• /
• 2006

Although the importance of size-resolved raindrops study has been known, it has not been popularized up to the present. In the present study, an attempt was made to generalize the size-resolved raindrops study by a combination of the frozen raindrop collection method and a commercially available high-performance capillary electrophoresis (HPCE). Samplings were carried out at Kyoto, Japan in October 2002. The inorganic ions (chloride, nitrate, sulphate, calcium, ammonium, sodium, magnesium, potassium) in size classified raindrop samples were successfully analyzed by HPCE with good repeatability. To assure the accuracy and precision of HPCE data, t-test was conducted with paired analytical data, which were experimentally constructed by analyzing standard solutions with HPCE and IC, respectively. T-test showed that there is no notable difference between the concentrations determined by the two analytical methods. Every ionic concentration in both cation and anion was found to be strong raindrop size dependence. Though there was slight increase of sodium and sulphate concentrations between 0.85 mm and 1.15 mm raindrop radius, it showed a strong decrease for every ionic component with increasing droplet radius. The combination of the frozen raindrop collection method and a commercially available HPCE can meet the need of size-resolved raindrops study.

• The Korean Journal of Applied Statistics
• /
• v.8 no.2
• /
• pp.87-97
• /
• 1995

When there is no main effcts or only one main effect in a $2 \times 2$ factorial design, Type I error rates and power for the rank transformed F test (FR test) for interaction are nearly equal to those of the classical F test. However the power of FR test is quite superior under the exponential distribution rather than the of FR test is quite superior under the exponential distribution rather than the normal distribution. Meanwhile when both main effects are in the model, Type I error rates of FR test, compared with those of F test, decrease as the effect size increases and are dependent on the fashion in which main effects are constructed. In addition, the power of FR test increases as the effect size and the sample size increase and is highly dependent on the manner in which main effects are constructed and the type of population distribution.

• Journal of the Korean Society of Radiology
• /
• v.14 no.1
• /
• pp.39-44
• /
• 2020

The purpose of this study was learning about chest X-ray image classification and accuracy research through Deep Learning using big data technology with Convolution Neural Network. Normal 1,583 and Pneumonia 4,289 were used in chest X-ray images. The data were classified as train (88.8%), validation (0.2%) and test (11%). Constructed as Convolution Layer, Max pooling layer size 2×2, Flatten layer, and Image Data Generator. The number of filters, filter size, drop out, epoch, batch size, and loss function values were set when the Convolution layer were 3 and 4 respectively. The test data verification results showed that the predicted accuracy was 94.67% when the number of filters was 64-128-128-128, filter size 3×3, drop out 0.25, epoch 5, batch size 15, and loss function RMSprop was 4. In this study, the classification of chest X-ray Normal and Pneumonia was predictable with high accuracy, and it is believed to be of great help not only to chest X-ray images but also to other medical images.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.03a
• /
• pp.755-758
• /
• 2010

본 연구에서는 토목구조물에 대하여 상사율을 고려한 1g 진동대실험(Shaking Table Test)과 전산해석을 수행하여, 실제 지진하중(단주기, 장주기, 인공지진)에 대한 토목구조물의 안정성을 분석 및 평가 하였다. 상사율에 따른 지표면 가속도 거동을 비교 분석하기 위하여 여러 가지 상사율을 적용한 실험을 수행하여 측정된 결과와 전산해석 결과를 상호 비교 분석하여 상사비에 따른 실험결과의 적절성을 평가하였다. 상사율을 1/50과 1/50보다 크게 조성하여 진동대실험과 전산해석 결과에 의하면, 지표면 가속도의 결과는 모두 유사한 결과를 보였다. 상사율 1:50 이상인 단면의 경우 진동대실험과 전산해석 결과 사이의 유사성이 떨어지는 것으로 볼 때, 1:50 이하인 상사단면이 실제 현장에서의 거동을 모사하는데 더 높은 신뢰성을 제공하는 것으로 판단된다.