• Coupled systems mechanics
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• v.12 no.4
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• pp.391-407
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• 2023

This paper presents a static study of a rectangular functional graded material (FGM) plate, simply supported on its four edges, adopting a refined higher order theory that looks for, only,four unknowns,without taking into account any corrective factor of the deformation energy with the satisfaction of the zero shear stress conditions on the upper and lower faces of the plate. We will have determined the contribution of these stresses in the transverse deflection of the plate, as well as their effects on the axial stress within the interfaces between the layers(to avoid any problem of imperfections such as delamination) and on the top and bottom edges of the plate in order to take into account the fatigue phenomenon when choosing the distribution law of the properties used during the design of the plate. A numerical statement, in percentage, of the contribution of the shear effect is made in order to show the reliability of the adopted theory. We will also have demonstrated the need to add the shear effect when the aspect ratio is small or large. Code routines are programmed to obtain numerical results illustrating the validity of the model proposed in the theory compared to those available in the literature.

• KDI Journal of Economic Policy
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• v.35 no.2
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• pp.1-39
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• 2013

Considering the relationship between state-owned enterprise (SOE) CEOs and political circles, this study examines the performance impacts of CEO's succession type, board chair separation, and industry expertise and finance expertise of CEOs and outside directors. I propose the definition of political independence in SOE CEOs based on the independence in appearance that might affect general people's perception. It means that there are no relationships or circumstances that might affect SOE CEO's judgment, activity, and report. The definition is able to overcome the limitations of the prior research that could not discover the CEOs who were affiliated to political circles because the research just distinguished the CEOs following their pre-jobs. This study focused on the performance impacts of political independence impaired CEO as well as the CEO's impacts on the relationship between the performance and other corporate governance variables. I selected as dependent variables the average return on asset as operating income divided by total assets and the average customer satisfaction rate evaluated by Korean government during the first three years following the year of the events of explanatory variables. My theory and evidence from the various CEO's personal background and financial information from SOEs in Lee Myung-bak Administration and Rho Moo-hyun Administration suggest the following important things. First, the analysis based on whether or not a SOE CEO keeps political independence shows that a political independence impaired CEO made a significantly negative impact on customer satisfaction rate. Second, the separation between a board chair and a CEO in SOEs introduced by Korean Act on Management of Public Institutions made a significantly positive impact on customer satisfaction rate. However, the positive impact of the board chair separation was removed in a political independence impaired CEO's SOE. Third, outside director's industry expertise made a significantly positive impact on return on asset. However, the positive impact of the outside director's industry expertise was removed in a political independence impaired CEO's SOE. Fourth, the comparison between Lee Myung-bak Administration and Roh Moo-hyun Administration on the corporate governance and performance of SOEs shows that the ratio of political independence impaired CEO was significantly higher in Lee Administration and the ratio of outside director's industry expertise and finance expertise were respectively significantly higher in Roh Administration. Based on these results, I suggested a few policy alternatives for CEO's improved political independence and requirements for executive's expertise in SOEs.

• 대한공업교육학회지
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• v.41 no.1
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• pp.128-146
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• 2016

The purpose of this study was to provide a basic research data for increasing the quality of 'creative engineering design' lesson and the teaching learning capability of high school teachers by analyzing the teaching learning management status and improvement plan of 'technology home economics subject' lesson for high school teachers. In order to investigate the teaching learning management status, the survey questionnaires from 63 teachers were collected from high school teachers who teach technology home economics subject currently and analyzed by statistical program SPSS 20. The main results of this study were as follows: First, for the contents of 'creative engineering design' lesson, the highest mean of response was 'creative thinking method'(M=4.22). In the learning activities, the teachers perceived the importance of the 'idea concept' highly. Second, in the management of 'creative engineering design' lesson, the teachers perceived the importance of the secure of tool, material budget, and practice space for the lesson highly. In the teaching capabilities, the teacher perceived the importance of the preparing teaching learning strategy most($$M{\frac{._-}{.}}4.14$$). Third, the teachers preferred to product for making uncomfortable things better in life and the other production outside from the content of textbook. Fourth, in the ratio of practice:theory lesson, they perceived the ratio of 3:7(36.5%), 4:6(25.4%), and 2:8(23.8%) are appropriate. In the assessment, the combination of production, portfolio, and presentation was preferred most. Fifth, there were statistically significant difference in teachers' interest and satisfaction and contents about 'creative engineering design' lesson between groups divided by the existence of practice space, certification held(technology teacher, non technology teacher), etc. Therefore, in order to improve the interest and satisfaction about the 'creative engineering design' lesson, the secure of space for technology practice and material budget were required. In addition, training and seminars program for improving the teaching capability for 'creative engineering design' lesson were required.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.2
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• pp.118-126
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• 2019

Purpose: This research is to investigate factors that affect dental aesthetics and analyze whether individual perception affects and difference of genders affects the esthetic factors. Materials and methods: Seventy dental students of Chonnam University aged from 25 to 35 years old without periodontal problems were included. Maxillary dental cast for participants were made, and standardized photo was taken with a digital camera. Maximum visual width and the position of gingival zenith of maxillary anterior teeth and maximum height of the maxillary central incisors were measured by a measurement program and the shape of central incisor was categorized. Questionnaire was conducted to evaluate esthetic perception. SPSS program was used to perform statistical analysis. Results: The average visual width ratio of right maxillary anteriors was 1.38:1:0.78 and 1.41:1:0.81 for the left which differ from the golden ratio. The width to height ratio for right and left central incisor was 0.84 and 0.83 respectively. The gingival zenith position was determined to be: mostly, central incisors and canines were located in the distal side, lateral incisors were located in the center. The visual width ratio of right maxillary anterior teeth, ratio of width to height of central incisor, gingival zenith position, crown morphology and amounts of gingival exposure upon smiling were not significantly different between genders, and facial patterns and these dental esthetic factors were not related to aesthetic perception. Conclusion: Even though participants had the visual width ratio of maxillary anteriors or ideal width to ideal height of central incisors that did not agree with the golden ratio, they had high satisfaction for dental esthetics. Esthetic perception depends more on subjective judgements of participants than objective indices.

• Journal of the Korean Society for Library and Information Science
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• v.32 no.2
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• pp.189-209
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• 1998

The purpose of this study is to verify the difference of behavioral characteristics between the primary and secondary search, the influence of the primary search results on Online databases. Data is collected by surveying the professional and end-user searchers in 33 online information service centers. 262 valid responses out of 308 questionaire are analyzed by the t-test, ANOVA, $\chi^2-test$ using SAS program. The major findings are as follows : (1) Preparatory searches(the levels of expectation, the degree of question comprehension), search results(the number of output documents, precision ratio, recall ratio, degree of satisfaction) are significantly different between the primary and secondary searches on Online Databases. But the number of search terms, Boolean logics, files, systems, relevant documents are not significantly different between the primary and secondary searches. (2) The results of the primary search affect the secondary searches. The number of output documents in the primary search affect the modification of search strategies and objects in the secondary searches. The number of relevant documents affect the variation of search scopes in the secondary searches. The precision ratio affect the change of search strategies and scopes in the secondary searches.

• Applied Chemistry for Engineering
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• v.28 no.4
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• pp.442-447
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• 2017

In this study, we extracted an antioxidant from natural products which are known to have a high antioxidant content and also optimized the extraction process by applying a response surface methodology (RSM). In addition, by measuring the total flavonoids and total polyphenols of the active ingredient extracted persimmon leaf and thistle, the functionality of the active ingredient was evaluated. Both ultrapure water and alcohol were used as extraction solvents and the ratio of ultrapure and alcohol, amount of sample, extraction time, extraction temperature were set as independence variables. Also, the yield, total polyphenols, and flavonoids was set as the response. Optimal extraction conditions were as follows; for persimmon leaf, the extraction time = 3.1 h, ratio of alcohol/ultrapure = 63.4 vol%, and temperature = $54.6^{\circ}C$ while for thistle the extraction time = 2.9 h, ratio of alcohol/ultrapure = 40.7 vol%, and temperature = $68.4^{\circ}C$. Also, the response were as follows; for persimmon leaf, the yield = 27.7%, total polyphenols = 33.2 mg GAE/g, and total flavonoids = 47.8 mg QE/mg dw, whereas for thistle the yield = 27.0%, total polyphenols = 17.9 mg GAE/g, and total flavonoids = 28.8 mg QE/mg dw at the optimal conditions. The overall satisfaction level was 71.7%.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.11
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• pp.990-999
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• 2013

Previous studies based on the theoretical evidence and based on the empirical data have been constantly revealing related factors affecting visual fatigue in viewing 3D images. however, the measurement data coupled with the factors that affect the viewers to feel fatigue is insufficient. this study research that the viewers feel the visual functional data is based on subjective fatigue such as IPD, AC/A ratio, and the degree of phoria and the effects on variance in these data, is to examine the correlation between these data. based on the average score of subjective fatigue which is $6.00{\pm}3.88$, total fatigue points from 0 up to 6 is classified as a group not appealing for the fatigue and from 7 up to 16, they were classified as the fatigue appealing group. the results showed no difference in satisfaction of the images by each subjective fatigue, IPD and far phoria. AC/A ratio was higher from the fatigue not appealing group, near phoria was higher from the fatigue appealing group. after watching 3D images, the fatigue not appealing group showed a tendency of higher increase of exophoria. correlations appeared in this experiment showed that AC/A ratio and near phoria are closely related to level of subjective fatigue which feel when watching 3D images. when watching 3D images based on two data appear to be able to predict the fatigue, even during content production fatigue reduce the data dimensions to be used as the main basis is expected.

• The korean journal of orthodontics
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• v.30 no.3 s.80
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• pp.367-375
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• 2000

If a mandibular prognathic patient has an extremely unnatural anteroposterior and vertical maxilla or keen esthetical perception for facial profile, orthognathic surgery must be performed along with orthodontic treatment, which alone cannot provide satisfactory results in this case. Esthetical improvement becomes an important factor in the satisfaction level of the patient's treatment result, but an attempt to objectively measure beauty holds many problems. Therefore, in the end, the patient submits the final esthetical evaluation based on his/her subjective viewpoint. Because Korean people have a tendency to prefer the facial appeareance of westerners, they favor an oval shaped face over the traditional round face. This research was conducted in response to the complaints raised by patients who claim that their face had become more round from widening of facial width after the orthognathic surgery for manidibular prognathism than before the surgery. The following results were obtained on the changes in facial appearance and patient satisfaction level by analyzing the skull P-A analysis of total of 14 patients (8 male and 6 female) who underwent orthognathic surgery primarily chief complaint for manidibular prognathism and from their responses on questionnaires. These results are to be used in the research on the pre- and post- operative changes in facial height and width from orthognatic surgery. 1. Three ($21.4\%$) of 14 patients said that their face had widened. 2. The A group showed no change in mandibular width but B group showed a 0.7mm reduction. The facial width increased by 0.45mm and 0.66mm in groups A and B, respectively, after the orthognathic surgery 3. After the surgery the facial length changed by an 0.52mm increase in upper facial height , 1.19mm reduction in lower facial height, and 0.7mm reduction in mandibular height in group A. In group B group, there was a 0.67mm reduction in upper facial height, 3.66mm reduction in lower facial height, and 5mm reduction in mandibular height. 4. In reference to facial width, the facial height showed $1.5\%$ reduction in group A and $3.6\%$ reduction in group B after the surgery. 5. In reference mandibular height-to-facial width ratio, there was a $1.3\%$ reduction in group A, and $4.4\%$ reduction in group B after the surgery. 6. In reference to the mandibular height-to-width ratio, there was a $1.3\%$ reduction in group A and $4.3\%$ reduction in group B after the surgery. 7. Although the change in the facial width due to surgery can be ignored, sufficient explanation should be Provided to the patient before surgery on the fact that the face can appear to be relatively wide because of the reduced facial length as result of the surgery.

• Journal of dental hygiene science
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• v.14 no.4
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• pp.516-524
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• 2014

Workers' oral health is important to guarantee workers' right of health and increase productivity. The aim of this study was to investigate recognition and satisfaction of national oral examination for workers in Incheon and Daejeon. Three hundred seventy-nine workers who were selected by convenience cluster sampling answered the questionnaire about experience, recognition and satisfaction of national health examination and oral examination by self recording type. A total of 76.0 percent of the subjects had national health examination, and 51.7% had national oral examination. A total of 64.9 percent had experienced notice about national health examination from the company, and 28.2% about national oral examination. The subjects had high positive score about intention of treatment, dental scaling, and change of toothbrushing method depending on oral examination, need of national health and oral examination, and usefulness to one's health through national health and oral examination. Office workers, regular workers, and the workers with monthly income more than 2 million won had more notice about national health and oral examination compared with sales and production workers, contract workers and the workers with monthly income less than 2 million won. We suggest institutional management of the notice about national oral examination be needed, especially for economically poor, or contract workers to increase the ratio to have national oral examination.

• Journal of the Korean association of regional geographers
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• v.18 no.1
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• pp.86-100
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• 2012

This study examines turnover intentions of social workers in the public and private sectors from a comparative perspective. Major findings of this study are as follows: 1. There exists a paradox between public and private social workers that private social workers show their turnover intentions more saliently than public social workers, even though the former is paid much less, but more satisfied with their jobs, and then expresses turnover intentions more often than the latter. 2. The 'voice hypothesis' can be an alternative explanation to figure out why the paradoxical difference exists between the two groups of social workers when we include the mechanism of empowerment into the equations regarding social workers' turnover intentions and job satisfaction. 3. The equity theory of motivation can explain the paradoxical difference if we make use of the meaning of the 'equity' formula which stands for the ratio between inputs and outputs exerted by the social workers.