• Korean Journal of Ichthyology
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• v.28 no.2
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• pp.79-86
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• 2016

Stomach contents of Amblychaeturichthys hexanema and A. sciistius (Perciformes: Gobiidae) from southeastern waters off Korea were analyzed to determine dietary habits and the presence of any inter- and intra-specific partitioning of food resources. These two species were bottom-feeding carnivores that consumed mainly benthic crustaceans, and other demersal invertebrates and planktonic organisms were also important in their diets. Non-metric multidimensional scaling (nMDS) ordination and multivariate analyses based on gravimetric contributions of the different prey taxa to stomach contents revealed significant inter-specific dietary differences; i.e. partitioning of food resources between the two species. Size-related changes, however, were not significant for their diets. Differences in the types and range of prey ingested by the two species could often be related to differences in the feeding behaviors. Our results of stomach contents analyses provide clear evidence of niche segregation between co-occurring A. hexanema and A. sciistius in southeastern Korean waters, which would reduce the likelihood of inter-specific competition for food resources.

• Journal of the Korean Institute of Gas
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• v.12 no.2
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• pp.77-84
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• 2008

Experimental study was conducted to clarify the importance of buoyancy effects in laminar lifted flames which have been well understood by cold jet similarity theory. To evaluate buoyancy effects, lifted flame behaviors were systematically observed in methane and propane lifted flames diluted with He as changing the fuel nozzle diameter from 0.1 to 6 mm. Important physical parameters such as fuel strength, flame stretch and flame curvature, which were derived through simple physical scaling laws, were estimated. It is experimentally proven that buoyancy effects are important in relatively large fuel nozzle diameter and large fuel dilution with He. The results of Chen et al., which displayed the existence of stably lifted flames for 0.5

• Structural Engineering and Mechanics
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• v.80 no.5
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• pp.503-522
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• 2021

This paper investigates experimentally and numerically the influence of drilling process on the mechanical and thermomechanical behaviors of woven glass fiber reinforced polymer (GFRP) composite plate. Through the experimental analysis, a CNC machine with cemented carbide drill (point angles 𝜙=118° and 6 mm diameter) was used to drill a woven GFRP laminated squared plate with a length of 36.6 mm and different thicknesses. A produced temperature during drilling "heat affected zone (HAZ)" was measured by two different procedures using thermal IR camera and thermocouples. A thrust force and cutting torque were measured by a Kistler 9272 dynamometer. The delamination factors were evaluated by the image processing technique. Finite element model (FEM) has been developed by using LS-Dyna to simulate the drilling processing and validate the thrust force and torque with those obtained by experimental technique. It is found that, the present finite element model has the capability to predict the force and torque efficiently at various drilling conditions. Numerical parametric analysis is presented to illustrate the influences of the speeding up, coefficient of friction, element type, and mass scaling effects on the calculated thrust force, torque and calculation's cost. It is found that, the cutting time can be adjusted by drilling parameters (feed, speed, and specimen thickness) to control the induced temperature and thus, the force, torque and delamination factor in drilling GFRP composites. The delamination of woven GFRP is accompanied with edge chipping, spalling, and uncut fibers.

• Journal of Korean society of Dental Hygiene
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• v.11 no.5
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• pp.615-627
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• 2011

Objectives : The study has three aims: 1) to assess the perceptions, attitudes, and behaviors of dental hygiene students and other college students towards oral and dental care, 2) to provide grounds for developing an oral and dental health educational program, and 3) to improve the oral and dental health status among the college student population. Methods : The subjects in this study were 520 students who included dental hygiene students from J health college and other majors from a four-year university located in Seoul. The survey was conducted from September, 2010, to June 3, 2011. The collected 507 questionnaires were analyzed. The collected data were analyzed by the statistical package SPSS WIN 12.0, and the level of significance was set at 0.05. Results : 1. As for a daily toothbrushing frequency, the largest number of the students brushed their teeth three times a day, and the dental hygiene students did that more often than the other majors(p<0.001). Concerning awareness of the toothbrushing method and the time for the change of the toothbrush, the rolling method was more prevailing among the dental hygiene students than the others(p<0.001). 2. In regard to education experience about the toothbrushing method and satisfaction with the existing toothbrushing method, 64.7% of respondents ever received education about the toothbrushing method(p<0.001). 3. As to scaling experience and gingival bleeding, the dental hygiene students had more scaling experiences(p<0.001), and the other majors who underwent gingival bleeding from time to time outnumbered the dental hygiene students who did(p<0.01). 4. In relation to subjective oral health status, the dental hygiene students found themselves to be in better oral health than the other majors(p<0.001), and the latter had more parts of the mouth in which they didn't feel well than the former(p<0.01). The dental hygiene students were more concerned about their oral health(p<0.001) and felt more uncomfortable in chewing(p<0.05). The other majors felt more uncomfortable in pronunciation(p<0.01). Conclusions : The results of this study indicated that dental hygiene students strongly recognized the importance of knowledge, motivation, and self-care behaviors, and attitudes towards oral health and dental care compared to other college students. It suggested that regular educational programs for the college student population should be implemented to increase their concern for oral and dental issues and to improve their oral and dental health status.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.1
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• pp.17-23
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• 2020

In this study, the behaviors of a vessel and the ground during the vessel impacting an underwater slope that is part of an artificial protective island are analyzed using the coupled Eulerian-Lagrangian scheme. To consider the large deformation including the shear failure of soil, the Eulerian domain is used to model the ground and water, while the impacting objects are modeled as the Lagrangian domain. For efficiency, the mass scaling scheme is applied to the modeling of the impacting objects, and the ground is modeled by setting the Eulerian volume fraction values. To verify the applicability of the constructed model, a dynamic penetration anchor problem is analyzed. The impacting vessel is modeled using solid elements following the external shape of a container ship, and an analysis of a collision on the slope is performed. As a result, collision behaviors such as displacement, velocity, and dissipation energy are estimated, and the necessity of a parametric study as further research is established.

• The Journal of Korean Society for School & Community Health Education
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• v.14 no.3
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• pp.1-14
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• 2013

Objectives: The purpose of this study was to investigate the possible impact factors(oral health level, oral health promotion behaviors, health level, health behaviors, and mental health) on oral health related quality of life using OHIP-14 of health allied college students. Methods: A total of 363 self-administered questionnaires were collected from university student in Seoul. To investigate the casual relationship between each variable presented in the research model, descriptive statistics, t-test, one-way ANOVA(Scheffe's test), man-whitney, kruskal wallis, multiple regression analysis were carried out by using SPSS ver. 21.0 Results: The study shows that the students reported mean score of OHIP-14 ($8.32{\pm}7.51$), of which physical pain was the highest score($1.88{\pm}1.45$) and social disability was the lowest score($0.69{\pm}1.13$). Multiple regression revealed that the score of OHIP-14 was shown to be significantly higher for the following people: who were get more self-reported symptom of periodontitis, halitosis, negative self-perceived general health and oral health, no received dental scaling treatment, and participants who had no experience awareness of distress in two weeks. The explanatory power was 18.2%. The most powerful factor regarding to self-reported symptom of periodontitis was shown to be negatively relations oral health-related quality of life. Conclusions: In order to enhance the students' life quality, there need to be considered for a comprehensive oral health-related quality of life program for the students through health education policy.

• Journal of Korean society of Dental Hygiene
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• v.17 no.5
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• pp.757-767
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• 2017

Objectives: The purpose of this study is to identify the associated factors with subjective oral symptoms experience of obesity adolescents. Methods: The study subjects were targeting 8,139 obesity adolescents and 55,601 non-Obesity adolescents who completed 2016 Korean Youth Risk Behavior Web-based survey. Dependent variables were subjective oral symptoms experiences of fracture teeth, pain, throbbing pain, periodontal pain & bleeding, mucosal disease and bad breath. Independent variables were demographic characteristics of the subjects, oral health behaviors, health behaviors and eating habits. Results: Obesity adolescents were 12.8% with 61.9% subjective oral symptoms experience. Regarding the related factors of subjective oral symptoms experience of obesity adolescents, the factors were identified to be significantly higher in high school (OR=1.72) compared to middle school, learning achievement was higher in middle (OR=1.09) and lower (OR=1.31) compared to high, economic status was higher in lower (OR=1.09) compared to high, sealant experience (OR=1.10) and scaling experiences (OR=1.12) responded no were higher compared to responded yes, smoking experiences responded yes(OR=1.08) were higher compared to responded no, sweet drink (OR=1.14) and fastfood (OR=1.13) consumption were higher in consumption compared to non-consumption and females (OR=0.46) were higher than males. Oral symptoms experience were lower that father and mother's level of education were under high school graduation (OR=0.86) compared to unknown, economic status was in case of middle (OR=0.93) compared to high, tooth brushing was lower in under 1 time (OR=0.76), 2 times (OR=0.61) compared to more than 3 times, vigorous physical activities responded no (OR=0.75) were lower, compared to yes, vegetable consumption was lower in non-consumption (OR=0.68) compared to consumption. Conclusions: Subjective oral symptoms experiences were identified higher in obesity adolescents than non-obesity adolescents. It would be useful to use the results of this study to reduce oral symptoms and necessary to develop a program system considering characteristics of obesity adolescents.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2126-2131
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• 2005

Interactions of a humanoid with a human are important, when the humanoid is requested to provide people with human-friendly services in unknown or uncertain environment. Such interactions may require more complicated and human-like behaviors from the humanoid. In this work the arm motions of a human are discussed as the early stage of human motion imitation by a humanoid. A motion capture system is used to obtain human-friendly arm motions as references. However the captured motions may not be applied directly to the humanoid, since the differences in geometric or dynamics aspects as length, mass, degrees of freedom, and kinematics and dynamics capabilities exist between the humanoid and the human. To overcome this difficulty a method to adapt captured motions to a humanoid is developed. The geometric difference in the arm length is resolved by scaling the arm length of the humanoid with a constant. Using the scaled geometry of the humanoid the imitation of actor's arm motions is achieved by solving an inverse kinematics problem formulated using optimization. The errors between the captured trajectories of actor arms and the approximated trajectories of humanoid arms are minimized. Such dynamics capabilities of the joint motors as limits of joint position, velocity and acceleration are also imposed on the optimization problem. Two motions of one hand waiving and performing a statement in sign language are imitated by a humanoid through dynamics simulation.

• The Journal of the Korea Contents Association
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• v.16 no.8
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• pp.81-89
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• 2016

This study performed an investigation to determine the impact of the oral health status and oral health behavior of pregnant women on quality of life and analyzed the results. The data was tested using the Shapiro-Wilk normality test for the key measuring parameters by using PASW Statistics 18.0. There were significant differences in subjective oral health status and oral health interest had significant differences depending on the period of in pregnancy. 46.5% of surveyed subjects considered themselves as 'healthy', and 51.2% considered their oral health status was 'healthy' while 57.5 responded they were interested in the oral health. As for the quality of life according to the oral health behaviors, when the subjects did not have any experience of receiving oral health education, when the tooth brushings were ${\leq}3$ times, when they had not received examination on a regular basis, and when they had no experience of scaling, the quality of life was very low. Significant impact variables on the OHIP-14 include longer pregnancy term, no experience of childbirth, subjective health status and poorer subjective oral health status, and the low health-related quality of life. In this study, it was considered as necessary to develop improved oral health education programs because the oral health-related quality of life was closely associated with oral health and oral health behaviors perceived subjectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.576-584
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• 2015

This research studiedthe correlation between dental implant patients' oral hygiene behaviors and satisfaction. By doing so, this study seeks to provide the basic data for the development of diagonal and educational programs to improve implant prosthesis maintenance and satisfaction. The data was collected from January 7 to June 30, 2014, analyzed by SAS (ver 9.2) and for this research, 6 dental hospitals and clinics in Daegu, Busan and Jinju, South Korea were examined for their implant patients receiving treatment. As a result, a total of 266 sets of data were investigated herein to reach the following findings: 1. The survey on status of dental implant prosthesis use and maintenance knowledge found 1.41 on average out of the total score of 3. 2. In the survey on implant prosthesis maintenance after putting in, the dental scaling cycle was found to be 'none' (63.2%). 3. In the survey on implant use status and satisfaction with their implant prosthesis, the masticatory function (p=0.001) were found to be significantly higher in the group using such oral-hygiene goods. 4. In the correlation analysis among one's knowledge on dental implant maintenance, discomfort and satisfaction, it was found that the more they used oral-hygiene supplementary goods (${\beta}=0.095$), the more they had knowledge on implant maintenance (${\beta}=0.069$) and the more they experienced oral health education (${\beta}=0.032$), the higher their satisfaction levels were. It is deemed that, for enhanced satisfaction of dental implant patients, their maintenance behaviors need to be further improved through oral health educational programs.