• Applied Chemistry for Engineering
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• v.19 no.2
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• pp.161-167
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• 2008

Multi-walled carbon nanotubes (MWCNT)-reinforced poly(ethylene-co-ethyl acrylate) (EEA) nanocomposites were prepared by both melt and solution mixing methods. The mechanical, thermal, and electrical properties were investigated as a function of type and loading of CNT. The tensile strength and modulus increased, while elongation at break decreased with increasing MWCNT content. The hollow-type MWCNT showed an improved tensile strength and elongation at break compared with a conventional MWCNT. The thermal degradation temperature was increased by around $40^{\circ}C$ with increasing the amount of MWCNT. The melt-mixed composites showed the highest volume resistivity. In the case of solution-mixed composites, the conventional MWCNT was estimated to show much lower volume resistivity than that of hollow MWCNT. The number and length of extruded CNT onto the fractured surface increased by both increasing the content of CNT and employing the tensile strain to the sample. The melt-mixed specimens showed much smaller number and shorter length of extruded CNT.

• Journal of Internet Computing and Services
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• v.19 no.1
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• pp.27-35
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• 2018

This paper is a study to classify malicious applications in Android environment. And studying the threat and behavioral analysis of malicious Android applications. In addition, malicious apps classified by machine learning were performed as experiments. Android behavior analysis can use dynamic analysis tools. Through this tool, API Calls, Runtime Log, System Resource, and Network information for the application can be extracted. We redefined the properties extracted for machine learning and evaluated the results of machine learning classification by verifying between the overall features and the main features. The results show that key features have been improved by 1~4% over the full feature set. Especially, SVM classifier improved by 10%. From these results, we found that the application of the key features as a key feature was more effective in the performance of the classification algorithm than in the use of the overall features. It was also identified as important to select meaningful features from the data sets.

• Health Policy and Management
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• v.18 no.3
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• pp.58-89
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• 2008

The purpose of this study was to evaluate comparatively the content of the Expanded National Immunization Program according to the provision method between 2005 and 2006 in Korea. We assessed the impact of the mutually exclusive vaccination policy using the result reports of the 2005 and 2006 Demonstration Project and the related references by the content analysis. The public health centers paid vaccination fees to the private clinic and hospital in the 2005 Demonstration Project in Daegu metropolitan city and Gunpo city. But, the public health centers directly supplied free vaccination services to the children in the 2006 Demonstration Project in Gangneung city, Yangsan city, and Yeongi-gun. The total budgets of 2005 and 2006 Demonstration Project were 6.57 billion won and 0.65 billion won, respectively. The computerized registration rates and timeliness rates of administration of each vaccination had improved all in the 5 Demonstration Project regions. However, the computerized registration rates of most vaccination in Gunpo city were higher than those in the 2006 Demonstration Project regions except hepatitis B. Especially, the computerized registration rate of BCG was 48.3%, but the BCG coverage rate by the follow-up telephone survey was 99.8% in Daegu metropolitan city. The community parents in all the regions were satisfied because of expanding financial and geographical access to immunization coverage. In conclusions, from the aspect of the main outcomes, the implementation of two different financial immunization aids appears to be widely accepted among these parents and to have had an impact on vaccination coverage. In the future, the government must try to enact that the national immunization policy including under-immunised or incompletely immunised groups would be achieved by the affordable method of the public-private dynamics.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.4895-4900
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• 2014

This study examined the impact of Government-ownership of banks on the firm size using South Korean data. The impact of Government ownership of banks as both the largest lender of government banks and the bank loan dependency of firms on government-ownership bank were measured. Empirical models considering endogenous problems and various effects of firm size were developed. All results in this paper showed that government-ownership of the main banks might have a relationship with the smaller firms. In addition, the bank loan dependency of firms on government-ownership banks might have effects on the firm size. A higher loan dependency of firms on government-owned banks resulted in smaller firms. This study used micro firm level data to analyze, from several perspectives, the relationship between government-owned banks and firm size. The existing studies go as far as inferring the effects of government-owned banks showing theoretical evidence, performing surveys, or using international comparison data. This study is differentiated from existing studies in that it analyzed in a direct manner the effects of the government-owned banks on both the firm size. This study provides insights into the privatization of government-owned banks.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.5
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• pp.93-101
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• 2016

In this study, the governing equations of motion for multi-cracked nonuniform nanobeam based on nonlocal elasticity theory and embedded in an elastic medium were derived. DTM(differential transformation method) was applied to vibration analysis of multi-cracked nonuniform nanobeam based on nonlocal elasticity theory and embedded in an elastic medium. The non-dimensional natural frequencies of this nanobeam were obtained for eoe, crack stiffness and elastic medium stiffness with various boundary conditions. The results obtained by this method was compared with previous works and showed the close agreement between two methods. The important conclusions obtained by this study are as follows : 1. As the length of nanobeam is shorter, the effect of scale coefficient is greater. 2. The locations of crack change non-dimensional natural frequency, In the case of fixed-fixed ends, the non-dimensional natural frequency is the biggest in the first crack location of 0.6L of nanobeam length, and the smallest in both ends. In the case of fixed-free ends, the closer the location of first crack go tho the free end, the bigger the non-dimensional natural frequency. 3. As the stiffness of crack is greater, the non-dimensional natural frequency is smaller, And the effect of crack stiffness is similar on both fixed-free ends and fixed-fixed ends. 4. The bigger the stiffness of elastic medium, the greater the non - dimensional natural frequency.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.1
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• pp.138-149
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• 2014

This study proposes an estimation method of strain distribution for multi-span steel beam structure under unspecific loading conditions. The estimation method in this paper employs the curve fitting using the least square method from measured strain data, not analytical method. To verify the proposed estimation method, a static loading test for multi-span steel beam on which distributed and concentrated loads act was conducted. The strain data for verification was measured by FBG sensors that have multiplexing technology. The analysis of the accuracy of strain estimation for distributed and concentrated loads and the errors by considering the number of measured points used in the estimation were conducted. In the maximum strain points, the strains could be estimated with the errors of 5.89% (loading step 1) and 6.26% (loading step 2). In case of decreasing the number of sensors, it was also confirmed that the errors increased (0.26~0.37%). Through the curve fitting method, it is possible to estimate the strain distribution (maximum strains and their locations) of multi-span beam for unspecific loads and go over the limit of the analytical estimation method which is suitable for specific distributed loads.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.1
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• pp.58-66
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• 2010

In this paper, we have constructed high-resolution topographical map of macro-tidal Malipo beach through integration of terrestrial LiDAR measurement and MBES survey data at inter-tidal zone. To acquire the enough information of inter-tidal zone, we have done terrestrial LiDAR measurement mounted on the roof of vehicle with DGPS through go-stop-scan method at the ebb tide and MBES depth surveying with tide gauge and eye staff measurement for tide correction and MSL calculation at the high tide all together. To integrate two kinds of data, we have unified the vertical coordination standard to Incheon MSL. The mean error of overlapped inter-tidal zone is about 2~6 cm. To verify the accuracy of terrestrial LiDAR, RTK-DGPS measurement have done simultaneously and the difference of Z value RMSE is about 4~7 cm. The resolution of Malipo topographical map is 50 cm and it has constructed to DEM (Digital Elevation Model) based on GIS. Now it has used as an input topography information for the storm-surge inundation prediction models. Also it will be possible to use monitoring of beach process through the long-term periodic measurement and GIS-based 3D spatial analysis calculating the erosion and deposition considering with the artificial beach transition and coastal environmental parameters.

• Journal of Korean society of Dental Hygiene
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• v.6 no.3
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• pp.187-201
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• 2006

The purpose of this study is to examine the satisfaction for college life and oral prophylaxis subject and improve the satisfaction for this subject by satisfying students' desire through the results of correlation, and to inspire a professional sense by helping students enjoy healthy college life. In order to achieve these purposes, 127 senior students of the Dental Hygiene Department, Kwangju Health College took part in this study to examine the satisfaction for a study course, a lab, professors, a college, and subjects. The following results were obtained. 1. The overall satisfaction for the Dental Hygiene Department was 2.83 and the highest dissatisfaction factors included difficult subjects and non-aptitude. The overall satisfaction for professors was 3.33 and students wanted professors' human contact with students and a well-prepared lecture. The overall satisfaction for college life was 2.65, suggesting not very high satisfaction, and the highest dissatisfaction factors included similar life to high school and surrounding environment. 2. The overall satisfaction for theory was 3.83 and for practice was 3.91 in oral prophylaxis. While the highest satisfaction was found in 'the objective and direction of class' and 'class and a supplementary lesson in not giving a lecture', the lowest satisfaction was found in 'experience in reading textbook-related materials or books'. 3. The correlation of the satisfaction of theory and practice of oral prophylaxis was examined. The satisfaction of oral prophylaxis theory was positively correlated with a school course, professors, and college, while the satisfaction of oral prophylaxis practice was positively correlated with a school course, professors, college, satisfaction of oral prophylaxis theory, and present health condition(p<0.05). 4. Factors influencing the satisfaction for the theory of oral prophylaxis included professors, while factors influencing the satisfaction for the practice were statistically significant in professors and health condition(p<0.05). Based on these results, in order for professional dental hygienists to be developed as professionals serving society, it is recommended to enhance the satisfaction for an oral prophylaxis subject and that professors should provide warm-hearted support and become a role model as an educator.

• Journal of Korean society of Dental Hygiene
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• v.16 no.5
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• pp.651-660
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• 2016

Objective: The purpose of the study is to investigate clinical skill proficiency in core dental hygiene competency in dental hygienists. Methods: The study subjects were 208 dental hygienists in Seoul and Gyeonggido. A complete self-reported questionnaire was filled out by 171 dental hygienists. The questionnaire consisted of general characteristics of the subjects, assessment of core dental hygiene competency, implementation of core dental hygiene competency, and education of core dental hygiene competency. Data were analyzed by PASW Statistics 18.0 to carry out a frequency analysis, one-way ANOVA and Pearson's correlation. Results: Chief complaint confirmation($4.08{\pm}0.91$), scaling (ultrasonic scaler)($4.36{\pm}0.88$), and toothbrushing education($4.35{\pm}0.86$) were found to be the most important in the areas of dental hygiene assessment, implementation, and education, respectively. In dental hygiene education, statistically significant differences were identified by 'level of education,' 'working career,' 'type of workplace,' 'department,' and 'main task.' Conclusions: Respondents were found to think that their level of proficiency should be above average for most jobs. Proficiency in core competency was shown to be different according to 'general characteristics of dental hygienists,' 'type of workplace,' and 'department.'

• Korean Journal of Environmental Agriculture
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• v.34 no.4
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• pp.282-287
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• 2015

BACKGROUND: The current study was carried out to investigate Cd, Hg, Pb and As contaminations in 222 commercial medicinal plants and to estimate the potential health risk through dietary intake of commercial medicinal plants in Korea.METHODS AND RESULTS: The Cd, Hg, Pb, and As in medicinal plants were analyzed by ICP/MS and mercury analyzer.The potential health risk was estimated using risk assessment tools. Total amount of Cd in medicinal plants with 29% samples exceeded the standard limit legislated in 'Pharmaceutical Affairs Act' while all plant samples were lower than the standard limit value for As, Hg, and Pb. However, when applying the standard limit for root vegetable (fresh weight) in the Food Sanitation Act, four samples exceeded the standard limit of Pb. For health risk assessment, the values of cancer risk probability were 0.3~5.9×10^-7which were less than the acceptable cancer risk of 10^-6~10^-4for regulatory purpose. Also, Hazard quotientvalues were lower than 1.0.CONCLUSION: Therefore, these results demonstrated that human exposure to Cd, Hg, Pb, and As through dietary intake of commercial medicinal plants might notcause adverse health effects although some medicinal plants were higher than the standard limit values for Cd and Pb.