• Journal of Sericultural and Entomological Science
• /
• v.15 no.1
• /
• pp.27-30
• /
• 1973

The present research has been carried out in an attempt to obtain fundamental data which contribute to enhansing the accuracy of cocoon reeling test and improving the method of it more effectively. The results obtained are as follows: 1. The standard deviation and coefficient of variation of percentage of reelability and of percentage of raw silk yield to the sample size tended to show a gradual decrease according to the increasing of the sample size. However, the significant differences in the standard deviation and coefficient of variation of percentage of reelability and of percentage of raw silk yield between the different sizes of the samples having more than 300 cocoons have not been observed according to their sizes. 2. The significant difference in the standard errors from percentage of reelability between the samples of 300 cocoons and 400 cocoons have not been observed. 3. The significant difference in the standad errors from percentage of raw silk yield between the samples of 300 cocoons, 500 cocoons and 600 cocoons have not been observed. 4. The significant difference in the standard deviation, the standard errors and coefficient of variation to the length of a bave between the different sizes of the samples have not been shown. 5. From the above result, it is estimated that the optimum sire of the sample for the cocoon reeling test is the 300 cocoons.

• Journal of the Korean Society of Earth Science Education
• /
• v.15 no.2
• /
• pp.224-234
• /
• 2022

The purpose of this study was to analyze STEAM elements and convergence types that appeared in the creative and convergent activities in elementary school science textbooks, which were converted from the national issuance system to the authorized system in 2022. For this study, 6 elementary school science textbooks for 3rd and 4th graders were selected. And STEAM elements in creative and convergent activities were analyzed by publishers, grade-semesters, and science fields, and the convergence type was analyzed for each publisher. The results of this study are as follows. First, the total frequencies of STEAM elements and the ratios of each element in the creative and convergent activities of textbooks were different for each publisher. However, among the four elements except for science (S) element in all publishers, the tendency to have a high proportion of art (A) element and a very low proportion of mathematics (M) element was common. Second, the higher the number of fused STEAM elements, the lower the rate of appearance in the textbooks in overall. Also the ratio of convergence types of STEAM elements varied by each publisher. Third, the ratio deviations of art (A), technology (T), and engineering (E) elements for each grade-semester were not large, but the ratio deviation of the mathematics (M) element was large. Fourth, technology (T) and engineering (E) elements appeared a lot in the fields of 'movement and energy' and 'material', while art (A) element appeared a lot in the fields of 'earth and universe', 'life', and 'integration'.

• Korean Management Science Review
• /
• v.8 no.1
• /
• pp.127-133
• /
• 1991

본 연구에서는 Karmarkar법의 변형인 Todd&Burrell 알고리즘을 분석하고 이 알고리즘의 수행속도를 증가시키기 위한 몇가지 방안을 제시하였다. 또한, 몇가지 실험을 통하여 제안된 방안들을 비교 분석하였다. 사영행렬의 계산에 QR 분해법과 Cholesky 분해법을 도입함으로써 계산 시간을 줄일 수 있었고, 구내최적화를 위한 개선폭의 결정에 비율검정법과 선형탐색법을 사용함으로써 수행횟수 및 총 수행시간을 줄일 수 있었다. 수행실험을 통하여 알고리즘을 분석한 결과, 수행시간의 대부분을 사영행렬의 계산이 차지하는 것으로 나타나 이론적으로 계산복잡도를 분석한 결과와 일치하였다. 또한, 사영행렬과 개선폭의 결정에 사용된 각 방법들을 실험을 통해 비교 분석한 바로는 사영행렬의 계산에 있어서 Cholesky 분해법이 Gauss소거법이나 QR 분해법을 쓰는 경우보다 우수했으며, 개선폭을 결정하는 데 있어서는 비율검정법이 속도면에서 가장 우수했다.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.32 no.1
• /
• pp.26-38
• /
• 2020

A statistical test was carried out on the IID (Independently and Identically Distributed) assumption of the AM (Annual Maxima) data used to estimate the design wave height. The test was divided into independence (randomness) test and homogeneity test, and each test was conducted on AM data of 210 and 310 stations in coastal and inner coastal grids in typhoon and non-typhoon (monsoon) conditions. As a result of the independence test, the rejection ratios of the test are in the range of 1.8~5.3% and 1.4~6.0% for the non-typhoon and typhoon data sets, respectively. On the other hand, in the distribution difference test of typhoon data and nontyphoon data, the same distribution hypothesis was found to be rejected in the range of 47~79% according to the test method for both coastal grid and inner coastal grid. Therefore, in estimating design wave height by extreme value analysis, the estimation process by dividing the typhoon and non-typhoon data is appropriate.

• The Korean Journal of Financial Management
• /
• v.16 no.1
• /
• pp.61-82
• /
• 1999

대주주들이 경영권을 직접 행사하고 있는 우리나라의 경영환경에서 기업의 의사결정은 대주주의 보유지분 정도에 따라 상당히 달라 질 수 있다. 즉, 소유경영자의 지분이 적으면 적을수록 경영자 자신의 이익과 전체 주주의 이익은 괴리되고 경영자의 경영상의 위험수용성(危險受容性)은 높아지게 된다. 이에 따라 내부지분율이 낮은 기업일수록 보다 높은 성장을 선호하고 위험성이 높은 투자대안을 선택할 가능성이 증대된다. 상기한 연구가설을 검정하기 위하여 94년부터 97년까지 4년간의 상장기업 자료를 이용하여 내부지분율과 부채비율, 그리고 성장률과의 관계를 분석하였다. 특히, 내부지분율을 포함하는 기업의 재무구조 다중회귀모형과 성장률의 다중회귀모형을 구축하여 내부지분율이 기업의 재무구조와 성장률에 대한 유의적인 설명력을 보유하고 없는지 여부를 검정하였다. 실증분석 결과는 내부지분율이 낮은 기업일수록 부채비율과 성장률이 상대적으로 높다는 연구가설을 일관성 있게 지지하고 있다. 이러한 연구결과는 정부의 기업정책에 대한 중요한 시사점을 던져주고 있다. 즉, 이제까지 기업들은 경영권에 대한 위협없이 내부지분율을 저하시킬 수 있었고, 이러한 상황에서 기업의 고부채, 고성장 전략은 소유경영자의 시각에서 볼 때는 극히 합리적인 것이었다. 하지만, 정부가 기업의 매수합병시장을 활성화시키면 많은 기업들은 경영권의 보호를 위해 내부지분율을 높이게 될 것이다. 이 경우 기업들은 보다 보수적인 경영을 하게 되어 부채비율은 낮아지고 과도한 성장정책은 지양될 것으로 예상된다. 따라서, 보다 건전한 기업경영을 유도하기 위해서는 내부지분율이 제고되어야 하고, 이를 위해서는 아직도 남아있는 매수합병의 장애요인들을 조속히 제거하는 것이 필요할 것이다.

• The Korean Journal of Applied Statistics
• /
• v.32 no.3
• /
• pp.331-348
• /
• 2019

Understanding the tumor heterogeneity due to differences in the growth pattern of metastatic tumors and rate of change is important for understanding the sensitivity of tumor cells to drugs and finding appropriate therapies. It is often possible to test for differences in population means using t-test or ANOVA when the group of N samples is distinct. However, these statistical methods can not be used unless the groups are distinguished as the data covered in this paper. Statistical methods have been studied to test heterogeneity between samples. The minimum combination t-test method is one of them. In this paper, we propose a maximum combinatorial t-test method that takes into account combinations that bisect data at different ratios. Also we propose a method based on the idea that examining the heterogeneity of a sample is equivalent to testing whether the number of optimal clusters is one in the cluster analysis. We verified that the proposed methods, maximum combination t-test method and gap statistic, have better type-I error and power than the previously proposed method based on simulation study and obtained the results through real data analysis.

• The Korean Journal of Applied Statistics
• /
• v.24 no.5
• /
• pp.883-891
• /
• 2011

For survival data we sometimes want to test a log normality hypothesis that can be changed into normality by transforming the survival data. Hence the Shapiro-Wilk type statistic for normality is generalized to randomly censored data based on the Kaplan-Meier product limit estimate of the distribution function. Koziol and Green (1976) derived Cram$\acute{e}$r-von Mises statistic's randomly censored version under the simpl hypothesis. These two test statistics are compared through a simulation study. As for the distribution of censoring variables, we consider Koziol and Green (1976)'s model and other similar models. Through the simulation results, we can see that the power of the proposed statistic is higher than that of Koziol-Green statistic and that the proportion of the censored observations (rather than the distribution of censoring variables) has a strong influence on the power of the proposed statistic.

• Animal Systematics, Evolution and Diversity
• /
• v.11 no.3
• /
• pp.359-377
• /
• 1995

Morphological and isozyme analyses were used to examine closely related species of Tridentiger obscurus and \ulcorner: brevispinis, a pair of cryptic species which has intricate problem with regard to species boundary, and to clarify the taxonomic position. In this study, it was revealed from their 17 allopatric streams that there are differences of band ornamentation on the lateral side and three genetic markers between two species. However, genetic relationship between them (S = 0.813, D = 0.192) was within the intraspecific level of similarity. However, at the sympatry of two species no hybrid was found except at Bangjuk stream where the electrophoretic hybrids with slight deficiency of heterozygosity were observed. It is shown that at sympatry there is a finer microenvironmental subdivision between two species at all populations including Bangjuk stream. To manifest the extent of assortative mating, four syrnpatric subpopulations at Bangjuk stream were analyzed for departure from Hardy-Weinberg equillibrium by F-statistics. All subpopulations were deviated significantly from the expectation under random mating. The evidences presented here supports the recognition of Tridentiger obscurus and T. brevispinis as semispecies in the late stage of reproductive isolation

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.19 no.4
• /
• pp.309-316
• /
• 1999

This Study was carried out to compare growth characteristics and yield of 10 cultivated soybean varieties, Jinpum I, Jinpum II, Hwanggum, Gumjung I, Gumjung II, Seukryangboot, Jangyup, Gumjungol, Bokwang, Manri for improvement of soiling crop. Plant height of Gumjung I(118cm), Gumjung II(114cm) and Jinpum I(114cm) were taller than other varieties based on dough stage. In total fresh weight and DM yield of Jinpum I, Jinpum II, Gumjung II were the highest of all varieties as 23,841kg, 23,499kg and 22,815kg per hectare, and 5,531kg, 5,173kg and 5,236kg per hectare, respectively. The highest leaf/stem ratio of ten soybean varieties were Manri(2.1), Jinpum I(1.9) and Hwanggum(1.9). Except early matured varieties, Seukryangboot(25.9%) and Gumjungol(25.4%), dry matter percent at dough stage were in the range of 22.0~23.4%. According to plant height, fresh weight, dry matter yield, and leaf/stem ratio, Jinpum I and Gumjung II were proper varieties to improve soiling crop.

• International Area Studies Review
• /
• v.13 no.3
• /
• pp.527-549
• /
• 2009

This paper investigates the relation of invert U-shape between the M/B ratio and leverage ratio by market, firm size, and a level of technology of firm. Our sample consists of 510 manufacturing firms continually listed on the Korea Securities Market and Kosdaq Market from January 1, 2001 to December 31, 2008. The total sample consists of the Korea Securities Market(large firms, high technology industry) sample of 2,248(1,816, 1,704) observations and the Kosdaq Market(small and medium firms, high technology industry) sample of 1,632(2,264, 2,376) observations. The empirical results show that the relation of invert U shape appears on the sample of the Kosdaq Market, small and medium firms, and high technology industry. However, the relation doesn't appear on the sample of the Korea Securities Market, large firms, and low technology industry. These mutually different results may be caused by the relatively low M/B ratio of the latter.