• 한국전산구조공학회논문집
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• 제29권6호
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• pp.583-590
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• 2016

본 논문은 강형식 기반의 MLS 차분법에 Rayleigh 감쇠효과를 적용한 동적균열진전 해석기법을 제시한다. Rayleigh 감쇠 효과가 반영된 동적 평형방정식과 구성방정식을 도출하고, MLS 미분근사식을 이용하여 지배방정식들을 이산화하였다. 평형방정식뿐만 아니라 구성방정식에서도 감쇠효과를 적절하게 고려하여 기존의 무요소 강정식화 기법에서 고려하지 못했던 비례감쇠 알고리즘을 구현하였다. 시간관련 항을 포함한 동적 평형방정식은 중앙차분법(central difference method)을 이용하여 시간적분 하였고, 속도에 대한 차분식을 lagging시켜 이산화 방정식을 간소화시켰다. 균열의 기하학적 특성은 표면력 '0'인 자연경계 조건을 균열면에 놓인 절점들에 부과하여 묘사하였으며, 균열성장으로 인해 해석단계마다 변하는 절점의 생성 및 이동 효과를 계방정식 구성에 반영하였다. 단일균열과 다중균열을 갖는 수치예제를 통해서 제안된 수치기법의 정확성을 검증하였으며, 비례감쇠 효과의 고려가 동적균열진전 해석결과에 미치는 영향을 보였다.

• 대한약리학회지
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• 제10권2호
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• pp.13-23
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• 1974

Results of an experiment on the general behavior of rats in order to explore the possible pharmacological actions of Panax Ginseng upon the central nervous system can be summarized as follows: 1) The rats treated with Ginseng-saponin intraperitoneally with the doses of 50 or 100 mg/kg show the decreased sleeping component and increase in lying and grooming component and walking and rearing component of general behavior. 2) There are no difference between control group and saline treated group in pattern of general behavior components. 3) In the Ginseng-saponin treated groups, the amphetamine stimulated walking and rearing component of genenarl behavior are reduced but lying and grooming component are elevated. 4) Ginseng-saponin shows very low acute toxicity in mice. The $LD_{50}$ in mice of 24 hours after intraperitoneal injection was 795 mg/kg. From the above findings, it is to suggest that the Ginseng saponin might stimulate the central nervous system but its mode of action appears to be different from that of amphetamine. And the effects of Ginseng saponin may be varied depending on various experimental situation or condition of animals.

• Tribology and Lubricants
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• 제12권3호
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• pp.115-122
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• 1996

In this paper, a finite difference method and the Newton-Raphson method are used to evaluate the Hamrock and Dowson's EHL film thickness formulas in elliptical contact problems. The minimum and central film thicknesses are compared with the Hamrock and Dowson's numerical results for various dimensionless parameters and with their film thickness formulas. The results of present analysis are more accurate and physically reasonable. The minimum film thickness formula is similar with the Hamrock and Dowson's results, however, the central film thickness formula shows large differences. Therefore, the Hamrock and Dowson's central film thickness formula should be replaced by following equation. $H_{c} = 4.88U^{0.68}G^{0.44}W^{0.096}(1-0.58e^{-0.60k})$ More accurate film thickness formula for general elliptical contact problems can be expected using present numerical methods and further research should be required.

• Communications for Statistical Applications and Methods
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• 제21권6호
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• pp.539-559
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• 2014

We derive the exact distribution of summation for random samples from uniform distribution and then compare the exact distribution with the approximated normal distribution obtained by the central limit theorem. To check the similarity between two distributions, we consider five existing normality tests based on the difference between the target normal distribution and empirical distribution: Anderson-Darling test, Kolmogorov-Smirnov test, Cramer-von Mises test, Shapiro-Wilk test and Shaprio-Francia test. For the purpose of comparison, those normality tests are applied to the simulated data. It can sometimes be difficult to derive an exact distribution. Thus, we try two different transformations to find out which transform is easier to get the exact distribution in terms of calculation complexity. We compare two transformations and comment on the advantages and disadvantages for each transformation.

• The Journal of Korean Physical Therapy
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• 제18권3호
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• pp.37-45
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• 2006

Purpose: This study analyzed changes in spinal neuron and action potential of motor unit depending on voluntary contraction on spinal neuron adaptation. Methods: It selected 80 university students in their twenties and divided into experimental groups of 25% MVIC (I), 50% MVIC (II), 75% MVIC (III) and 100% MVIC (IV) depending on maximum voluntary isometric contraction (MVIC) and performed isometric exercise of plantar flexor muscle to each experimental group with given contraction for 20 times. It measured Mmax, H/Mmax, Hmax latency, V/Mmax, V wave latency before and after exercise, compared method and volume of contraction. Results: H/Mmax ratio showed significant difference in comparison among groups (p<0.01) and there was difference in I and IV groups. V/Mmax ratio showed significant difference in comparison among experimental groups (p<0.05) and there was difference in I and IV groups. When voluntary contraction level was maximum, changes were greatest. However, no significantly difference was to Mmax, H latency and V wave latency. Conclusion: These results suggest that amplitude changes of voluntary contraction level, spinal neuron and supra-spinal neuron had a dose connection that the more contraction level, the better central activation seem to decrease highly for a short time.

• 한국연초학회지
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• 제27권1호
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• pp.5-10
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• 2005

Studies on effect of Decyl alcohol EC and Butralin EC on tobacco sucker control were conducted in the tobacco field of Agro-tech Research Group of KT&G Central Research Institute, in 2004. Control effects of two chemicals were highest at the sucker length of 1$1\~2cm$. This indicates that the first application of Decyl alcohol should be conducted before button stage in the flue-cured and at the button stage in the burley tobacco. Effects of Decyl alcohol and Butralin on sucker control were $89.6\%\;and\;90.7\%$, respectively at 14 days after application in the variety KF118. But that of sequential application of two chemicals was $81.9\%$ at 30 days after application in the variety KF118 and $86.1\%$ in the variety KB303. Effect of two applications of Yellow ribbon or Butralin was highest in two varieties. The central downward spray showed a little higher control effect than the pouring of two chemicals. There was not significant difference of sucker control effect between forty and fifty times solution of Decyl alcohol in the variety KB303.

• The Journal of Advanced Prosthodontics
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• 제9권2호
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• pp.93-98
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• 2017

PURPOSE. The purpose of this study was to compare the width ratio of maxillary anterior teeth according to age in the Korean population and to evaluate the maxillary central incisor width-to-length (W/L) ratio, given differences in age and gender. MATERIALS AND METHODS. Ninety-three Korean adults were divided into 3 groups (n = 31) by age. Group I was 20 - 39 years old, Group II was 40 - 59 years old, and Group III was over 60 years of age. After taking an impression and a cast model of the maxillary arch, the anterior teeth width ratio and central incisor W/L ratio were calculated from standard digital images of the cast models using a graph paper with a digital single lens reflex (DSLR) camera. The calculated ratios were compared among all groups and central incisor W/L ratio were analyzed according to age and gender. All comparative data were statistically analyzed with one-sample t-tests, one-way ANOVAs with Tukey tests, and independent t-tests. RESULTS. No significant differences in maxillary anterior teeth ratios were found among the age groups. The maxillary central incisor W/L ratios in Group III were the greatest and were significantly higher than those in the other groups. The central incisor W/L ratio of men was higher than that of women in Group II. CONCLUSION. Maxillary anterior teeth width ratios were similar in all age groups in the Korean population. The maxillary central incisor was observed as worn teeth in the group over 60 years of age, and a significant difference between genders was found in 40 to 50 year olds.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.256-256
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• 2017

The purpose of this study was to evaluate the effects of rice cultivars (Hangaru, Seolgaeng, Dasan-1 and Anda) on quality characteristics of rice beer. As for moisture content, Hangaru and Seolgaeng that are soft rice were higher than Dasan-1 and Anda as 14.48 and 14.62%, respectively. Dasan-1 and Anda showed higher protein content as compared to other varieties. As for amylose content, Hangaru turned out to be lower than other varieties as 17.71%, whereas reducing sugar content of Hangaru and Seolgaeng was higher than Dasan-1 and Anda. Results of hardness showed that Hangaru and Seolgaeng were measured lower than Dasan-1 and Anda. As a result of measuring alcohol content, pH and color of beer brewed by rice cultivars, no significant difference by cultivars was found, but measurement result of bitterness showed that beer brewed with Hangaru and Seolgaeng showed lower bitterness comparing to the beer brewed with Dasan-1 and Anda. The results of this study suggest that Hangaru and Seolgaeng are considered cultivars suitable for brewing quality of rice beer.

• 대한치과교정학회지
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• 제45권5호
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• pp.245-252
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• 2015

Objective: To assess the labial and lingual alveolar bone thickness in adults with maxillary central incisors of different inclination by cone-beam computed tomography (CBCT). Methods: Ninety maxillary central incisors from 45 patients were divided into three groups based on the maxillary central incisors to palatal plane angle; lingual-inclined, normal, and labial-inclined. Reformatted CBCT images were used to measure the labial and lingual alveolar bone thickness (ABT) at intervals corresponding to every 1/10 of the root length. The sum of labial ABT and lingual ABT at the level of the root apex was used to calculate the total ABT (TABT). The number of teeth exhibiting alveolar fenestration and dehiscence in each group was also tallied. One-way analysis of variance and Tukey's honestly significant difference test were applied for statistical analysis. Results: The labial ABT and TABT values at the root apex in the lingual-inclined group were significantly lower than in the other groups (p < 0.05). Lingual and labial ABT values were very low at the cervical level in the lingual-inclined and normal groups. There was a higher prevalence of alveolar fenestration in the lingual-inclined group. Conclusions: Lingual-inclined maxillary central incisors have less bone support at the level of the root apex and a greater frequency of alveolar bone defects than normal maxillary central incisors. The bone plate at the marginal level is also very thin.

• 한국지리정보학회지
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• 제26권3호
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• pp.65-84
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• 2023

지자체 차원의 균형발전 계획을 수립하기 위해서는 현 상태의 도시공간구조를 파악해야 한다. 특히 중심지는 균형발전의 핵심 요소이므로 그 위치와 규모를 정확히 판단하는 것이 필요하다. 따라서 본 연구는 부산시를 대상으로 중심지 체계를 식별하고 중심지의 기능을 누릴 수 있는 중심지의 영향권에서 소외되는 지역을 도출하고자 하였다. 중심지 체계 식별을 위해 부산시 전역에 대해 4개 지표(지가, 생활인구, 카드 소비, 상업 용도 건축물)를 활용하여 중심지 면적 지수를 산출하고 Getis-Ord Gi*와 DBSCAN 분석을 수행하였다. 식별된 중심지에 대해서는 위계를 구분하고 위계별 네트워크 분석을 통해 영향권을 도출하였다. 분석 결과 중심지는 서면, 중앙, 연산, 장산, 해운대, 덕천, 동래, 대연, 사상, 부산대, 부산역, 사직 총 12곳으로 나타났다. 중심지 영향권 소외지역은 대부분 동부산권역과 서부산권역에서 나타났으며 노후 공업지역과 주거지역, 신도시 일부에서도 도출되었다. 본 연구는 기존 연구에서 다루지 않았던 머신러닝 방법론을 적용하여 기존 계획상 중심지와 실제 데이터 간 차이를 밝히고 중심지 위치와 소외지역을 식별하였다는 점에서 의의가 있다.