• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2005.11a
• /
• pp.53-56
• /
• 2005

In this study, the material characterization and the dynamic behavior of 3D orthogonal woven composite materials has been studied under transverse central low-velocity impact condition by means of the micromechanical model using finite elements. To build up the micromechanical model considering tow spacing and waviness, an accurate unit structure is stacked in x-y-z direction repeatedly. First, the mechanical properties of 3D orthogonal woven composites arc obtained by means of virtual experiment using full scale Finite Element Analysis based on the DNS concepts, and the computed elastic properties arc validated by comparison to available experimental results. Second, using the implementation of this validated micromechanical model, 3D transient finite-clement analysis is performed considering contact and impact, and the impact behavior of 3D orthogonal woven composite is investigated. A comparison study with the homogenized model will be carried out in terms of global and local behaviors.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2002.10a
• /
• pp.170-174
• /
• 2002

In this study, the material characterization and the dynamic behavior of 3D orthogonal woven composite materials has been studied under transverse central low-velocity impact condition by means of the micromechanical model using finite elements. To build up the micromechanical model considering tow spacing and waviness, an accurate unit structure is stacked in x-y-z direction repeatedly. First, the mechanical properties of 3D orthogonal woven composites are obtained by means of virtual experiment using full scale Finite Element Analysis based on the DNS concepts, and the computed elastic properties are validated by comparison to available experimental results[9]. Second, using the implementation of this validated micromechanical model, 3D transient finite-element analysis is performed considering contact and impact, and the impact behavior of 3D orthogonal woven composite is investigated. A comparison study will be carried out in terms of energy absorption capabilities.

• Phonetics and Speech Sciences
• /
• v.1 no.2
• /
• pp.63-73
• /
• 2009

The present study was conducted to explore how the processing of lexical ambiguity between homonymy and polysemy differs from each other, and whether the representation of mental lexicon was separated from each lexical ambiguity by a semantic priming paradigm. Homonymy (M1 means the literal meaning of '사과', i.e. apple and M2 means another literal meaning of '사과', i.e. apologize) was used in Experiment I, and polysemy (M2 means the literal meaning of '바람', i.e. wind and M2 means the figurative meaning of '바람', i.e. wanton) was used in Experiment 2. The results of both experiments showed that a significant semantic priming effect occurs regardless of the type of ambiguities (homonymy and polysemy) and the difference of their semantic processes. However, the semantic priming effect for polysemy was larger than that for homonymy. This result supports the hypothesis that the semantic process of homonymy is different from that of polysemy.

• Journal of information and communication convergence engineering
• /
• v.20 no.3
• /
• pp.153-159
• /
• 2022

Plain radiographic analysis is the initial imaging modality for suspected small bowel obstruction. Among the many features that affect the diagnosis of small bowel obstruction (SBO), the presence of gas-filled or fluid-filled small bowel loops is the most salient feature that can be automatized by computer vision algorithms. In this study, we compare three frequently applied pixel-clustering algorithms for extracting gas-filled areas without human intervention. In a comparison involving 40 suspected SBO cases, the Possibilistic C-Means and Fuzzy C-Means algorithms exhibited initialization-sensitivity problems and difficulties coping with low intensity contrast, achieving low 72.5% and 85% success rates in extraction. The Adaptive Resonance Theory 2 algorithm is the most suitable algorithm for gas-filled region detection, achieving a 100% success rate on 40 tested images, largely owing to its dynamic control of the number of clusters.

• Restorative Dentistry and Endodontics
• /
• v.41 no.3
• /
• pp.231-234
• /
• 2016

• Restorative Dentistry and Endodontics
• /
• v.41 no.1
• /
• pp.74-78
• /
• 2016

• Journal of the speleological society of Korea
• /
• no.4
• /
• pp.23-32
• /
• 1996

The geographic environment means the general state of the environment in the area. Especially, which means the generation cause, the development process of the cave, and the validity of cave development and conservation in the side of the place of the cave. This study put emphasis on lying in which place Hwaam cave in Tong-myon, Chong son-gun, Kangwondo is situated and having in which stand is in comparison with other districts, and how the geological structure which determine the cave forming cause is.(omitted)

• Journal of the Korean Professional Engineers Association
• /
• v.29 no.2
• /
• pp.71-79
• /
• 1996

This paper evaluates the clustering performance of a neural network and a statistical method. Algorithms which are used in this paper are the GLVQ(Generalized Loaming vector Quantization) for a neural method and the k -means algorithm for a statistical clustering method. For comparison of two methods, we calculate the Rand's c statistics. As a result, the mean of c value obtained with the GLVQ is higher than that obtained with the k -means algorithm, while standard deviation of c value is lower. Experimental data sets were the Fisher's IRIS data and patterns extracted from handwritten numerals.

• Communications for Statistical Applications and Methods
• /
• v.4 no.3
• /
• pp.715-723
• /
• 1997

Multivariate control statistics to simultaneously monitor both means and variances for several quality variables under multivariate normal process are proposed. Performances of the proposed multivariate charts are evaluated in terms of average run length(ARL). Multivariate Shewhart chart is also proposed to compare the performances of multivariate exponentially weighted moving average(EWMA) charts. A numerical comparison shows that multivariate EWMA charts are more efficient than multivariate Shewhart chart for small and moderate shifts and multivariate EWMA scheme based on accumulate-combine approach is more efficient than corresponding multivariate EWMA chart based on combine-accumulate approach.

• Journal of Oriental Neuropsychiatry
• /
• v.11 no.2
• /
• pp.113-122
• /
• 2000

In order to understand the psychological charateristics of Sasang Constitution. the Korean version of 20-item Toronto Alexithymia Scale(TAS-20K) was completed by 59 sixth grade students of oriental medical college of KyungHee university who defined as one of Sasang constitution from June 2000 to August, and the mean scores of Yangin versus Eumin and Sasang constitution on TAS-20K was compared. The results of this study were as follows.1. Comparison between male and female on Means of TAS-20K ScoreMann-Whitney U test detected no significant differences between mean ranks of TAS-20K scores of male and those of female in F1, F2 and Total, but significant difference in F3(Mann-Whitney U test, t=2.493. p=.018)2. Comparison between Yangin and Eumin on Means of TAS-20K ScoreMann-whitney U test detected no significant differences between mean ranks of TAS-20K scores of Yangin and those of Eumin in F1. F3 and Total, but significant difference in F2(Mann-Whitney U test. t=-2.805. p=.008)3. Comparison among Sasang constitution on Means of TAS-20K ScoreAlthough mean of TAS-20K score of Taeyangin. Soyangin and Soeumin, there were no significant differences among Sasang constitution in F1, F2 and F3 as well as Total when mean ranks of TAS-20K scores of Sasang constitution were compaed by one-way ANOVA.