• Elastomers and Composites
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• v.46 no.2
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• pp.164-170
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• 2011

In this study, silicone rubber filled with environmentally-friendly perlite was prepared by mechanical mixing in order to improve thermal properties, such as heat and fire resistances. We found that the properties of silicone rubber composites depended on perlite concentration by various characterization methods. Thermogravimetric analysis(TGA) indicated that the initial degradation temperature of silicone/perlite composite was higher than that of pristine silicone rubber. The gas torch test showed that the opposite side temperature of composite materials was remarkably low as compared to that of pristine silicone rubber. In addition, the composites containing 5 wt% and 10 wt% of perlite showed remarkable thermal stability at elevated temperatures according to the results of both fireproof furnace tests under the RABT condition and carbonization furnace tests. The images from a scanning electron microscope(SEM) showed the degree of dispersion of perlite in silicone rubber. Finally, it was confirmed that limited oxygen index(LOI) was increased with perlite concentration.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.33 no.1 s.60
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• pp.23-28
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• 2007

Ascorbic acid (vitamin C, AsA) has been known as a strong reducing agent and is supposed to retard the synthesis of melanin pigment. A main problem that arose in using vitamin C in cosmetic formulation was its poor stability and low skin permeability, which result in low lightening efficacy in clinical trials. In this study, iontophoretic gel patch with flexible thin layer battery was employed in order to enhance skin permeation of vitamin c derivative (ascorbyl glucoside, AsAG) and to increase its lightening efficacy. in vitro iontophoretic skin permeation and stability of AsAG, safety and clinical lightening efficacy of iontophoretic patch containing 2% AsAG solution were examined. A optimun current of ionthophoretic patch for korean women was 0.1 mA, considering the skin permeability and skin irritation of consumers. We suggest that iontophoretic gel patch could be a safe system for enhancing the skin permeation of AsAG and lightning efficacy.

• Polymer(Korea)
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• v.30 no.3
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• pp.271-278
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• 2006

In order to investigate the structure and dynamics of atatic poly (vinyl alcohol) (PVA)/water system, laser light scattering experiment has been done in the semi-dilute concentration regime at $25^{\circ}C$. The scattering intensity I(q) can be analyzed with the fractal equation of $I(q){\sim}q^{-m}$ instead of Onstein-Zernike type equation. The fractal dimensionality m was found to be constant after reaching the plateau value of $m=2.6{\pm}0.3$ above C=3wt%. The time correlation function of dynamic light scattering has always two different modes such as fast mode and slow one. The cooperative diffusion of fast mode showed concentration independence contrary 4o the reptation theory's concentration dependent exponent of 3/4. The slow mode can be interpreted as the motion of large scale heterogeneities and its strong concentration dependence is apparent with a large negative exponent of -3.0. It is considered that the stereo-regular arrangement with four successive meso units of -OH plays as a key role in forming such heterogeneity.

• Journal of Korea Water Resources Association
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• v.47 no.10
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• pp.973-983
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• 2014

This study focused on the selection of appropriate plant species of VFS (vegetative fiter strips) and the assessment of VFS effects for reducing NPS (non-point source) pollution from uplands. The experimental field was constructed with 1 control and 6 treated plots in the upland area of $1,500m^2$ with 5% slope which is located in Gunwi-gun, Gyeongbuk province. Six vegetation including Chufa, Common crabgrass, Barnyard grass, Turf grass, Tall fescue, Kenturky bluegrass, were applied to install VFS systems during the study period from June 2011 to Dec. 2012. The results of this study showed that 6.1~77.8% in runoff and 15.6~90.3% in TS, 49.9~96.6% in T-P, and 6.7~91.1% in T-N were reduced from the VFS treated plots. Generally high reduction effects were observed from TS, T-P, T-N, and SS, while BOD, TOC, and $NO_3^-$ showed low reductions. The best vegetation type was Turf grass showing higher reduction effects of NPS pollutions and having relatively easier maintenance efforts compared to other vegetations selected in this study. Based on these results, VFS technique found to be an effective management practice for reducing agricultural NPS pollutions in Korean upland conditions. Further study needs to be performed through various field experiments with long term monitoring in order to develop a design manual of VFS system for practical applications.

• The Journal of the Korea Contents Association
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• v.14 no.3
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• pp.176-185
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• 2014

This study deals with the precedents regarding music works among 'The suits to claim an infringement of copyright' and 'Suits to claim indemnification for damage' that have been filed in Korea up so far in order to establish clear criteria to judge plagiarism based on the ground of legal judgment and judge the similarity of two works that have been in controversy previously. The study has been performed through literature review and also precedents. According to the study result, 'criteria to judge music works on plagiarism' are largely classified into (1) creativity, (2) access, and (3) substantial similarity. It is almost the same to judge creativity and substantial similarity. With the components of music works, say, melody, harmony, and rhythm, comparative analysis is conducted. About creativity, the original composer's song is analyzed with another object to be compared whereas about substantial similarity, two songs in controversy get to be analyzed. Regarding the current criteria to judge creativity, it is needed to set the number of objects to be compared which have been regarded similar. And access has limitations in setting up objective criteria for it. Lastly, we should develop digitized criteria for substantial similarity based on the preliminary review system of the Committee on Performance Ethics in the past.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.4
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• pp.173-180
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• 2014

Compressive sensing is a new signal acquisition paradigm that enables sparse/compressible signal to be sampled under the Nyquist-rate. To fully benefit from its much simplified acquisition process, huge efforts have been made on improving the performance of compressive sensing recovery. However, concerning color images, compressive sensing recovery lacks in addressing image characteristics like energy distribution or human visual system. In order to overcome the problem, this paper proposes a new group-sparsity hard thresholding process by preserving some RGB-grouped coefficients important in both terms of energy and perceptual sensitivity. Moreover, a smoothed group-sparsity iterative hard thresholding algorithm for compressive sensing of color images is proposed by incorporating a frame-based filter with group-sparsity hard thresholding process. In this way, our proposed method not only pursues sparsity of image in transform domain but also pursues smoothness of image in spatial domain. Experimental results show average PSNR gains up to 2.7dB over the state-of-the-art group-sparsity smoothed recovery method.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.2
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• pp.22-34
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• 2011

This paper presents the investigation results of a research on how engineers can analyze the economic effect of the ETCS(Electronic Toll Collection System) installed to minimize the vehicle delays on freeway tollgates during toll payments. This research considered this economic effect to occur in the form of vehicle passing time reductions at the ETCS, and the multi-service queuing theory was applied to estimate these values. This research found: 1) When vehicles approaching tollgates show Poisson distribution and the service time of the ETCS shows Exponential distribution, the multi-service queuing theory would be applicable for estimating vehicle passing times at toll-gates, 2) Despite the ETCS placement, exit sections of tollgates give a greater reduction of vehicle passing times than entering sections due to more delays at conventional toll payments, and 3)The ETCS would not guarantee vehicle passing time reductions all the time, because in such a case as many vehicles were queuing at the ETCS, the total delay level for a toll gate would increase greatly. In addition, in order to examine the accuracy of the estimated vehicle passing values, this research compared the values from the multi-service queuing theory with the observed values from a set of field survey values at freeway toll-gates, and found that the two values were in a good agreement with a very low error range of 1-3 seconds per vehicle. Based on this result, the multi-service queuing theory was recommended for practice.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.2
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• pp.128-139
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• 2017

Railway is one of the public transportation systems along with shipping and aviation. With the recent introduction of high speed train, its proportion is increasing rapidly, which results in the higher risk of catastrophic failures. The wheel bearing to support the train is one of the important components requiring higher reliability and safety in this aspect. Recently, many studies have been made under the name of prognostics and health management (PHM), for the purpose of fault diagnosis and failure prognosis of the bearing under operation. Among them, the most important step is to extract a feature that represents the fault status properly and is useful for accurate remaining life prediction. However, the conventional features have shown some limitations that make them less useful since they fluctuate over time even after the signal de-noising or do not show a distinct pattern of degradation which lack the monotonic trend over the cycles. In this study, a new method for feature extraction is proposed based on the observation of relative frequency energy shifting over the cycles, which is then converted into the feature using the information entropy. In order to demonstrate the method, traditional and new features are generated and compared using the bearing data named FEMTO which was provided by the FEMTO-ST institute for IEEE 2012 PHM Data Challenge competition.

• Korean Journal of Health Education and Promotion
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• v.5 no.2
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• pp.110-141
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• 1988

This study was conducted to find out the mental health state of high school students. First-year students and third-year students af liberal high schools is Seoul were subject to this study. Questionnaire of Symptom Checklist-90 and various factors was adopted for the survey. A total of 916 questionnaires was sellected for the analysis, and the results are obtained as follows; 1) The characteristics in responses to mental health scale showed that obsessive-compulsive scale score was the highest, followed by interpersonal-sensitivity, depression, hostility, and anxiety. The subject group of the students showed higher scores in nine symptom dimensions except somatization than other normal group. 2) Girl-students showed higher scores than boy-students in somatization, depression, and anxiety, whereas the opposite was true in hostility. 3) Third-year students got high scores, in somatization, anxiety and Depression. 4) Parental marriage state of the repondents showed significant differences in nine symptom dimensions of mental health. Scores of the students with parents was the lowest, followed by those of students with only mother, only father and the rest(no parents, divorced, sepaerated, step-parent) in increasing order. 5) Smoking students showed high score in obsessive-compulsive, depression, hostility, paranoid ideation, and psychoticism. Especially in hostility, they got much higher score. 6) Students with poor record at school got higher scores in every symptom dimension than those with good record at school, especially in obsessive-compulsive and depression scale. 7) Parents' attitude toward student showed significant effect on every scale. Students under over-expectation or indifference from parents were in bad mental health state. 8) Students who have advisor proved to be in better mental health state than those who never consult their personal problems with others. 9) He who has family history got higher scores in some scales. 10) Respondents who looked upon what they have learned in high school as being rather an obstacle to sound social life got high scores in all the symptom dimensions and next came those of the students who answered that there were a lot of unnecessary things in their learning. 11) Those for whom it would not quite necessary to enter college if there were little formal schooling discrimination in society got high scores in obsessive-compulsive, interpersonal sensitivity, depression, hostility, and in psychoticism, especially higher in obsessive-compulsive scale. 12) Mental health state of the students who are influenced by the social surroundings, mass media, and the home environments showed high score in 8 symptom dimensions. 13) Abnormal response frequency of this sample is as follows; 24.0％ of boys, 23.8％ of girls, 22.5％ of the first-year students, and 26.9％ of the third-year students. There were significant difference among the grades. 14) The factors of distinctive correlation between the dimensions of SCL-90 and 16 factors were the father's negative attitude and depression, negative responses on teaching contents and anxiety, and smoking and hostility. In conclusion, mental health state of liberal highschool students on the whole showed worse than other normal groups. It had close terms with relation with their parents, schoolwork, smoking, teaching contents, the social surrounding, mass media, and the home environments. Thus I believe there need not only mental health education of students, training of teachers, counceling of parents, but also changes in teaching contents, and the improvement of educational system and the social surroundings under the national support.

• Culinary science and hospitality research
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• v.23 no.2
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• pp.45-55
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• 2017

The fundamental objective of cultivating organic farm produces is to preserve the natural environment and protect eco system so as to maintain the environment where people can live. In the current social atmosphere, the value and attitude of the college students to the environment are significant as they will take the leading part in the future. College students in Busan participated in the survey for the study to prove the moderating effect of the confidence with organic farm produces by investigating the casual relationship among the purchase intention, the environmentally-friendly attitude, and the consumption value of college students. The questionnaires were distributed over the period from October $15^{th}$, 2016 to $30^{th}$.261 papers of the questionnaires were analyzed with SPSS (V 23.0) and AMOS (V 21.0) programs. The analysis on Confidence, Confirmatory Factors, Structural Equation Modeling was compared with Chi-square considering the degrees of freedom between the two models in order to investigate the moderating effect from the purchasing frequency. The result from the analysis confirms that there is a casual relationship between college students' values of organic farm products and the environmentally-friendly attitude. Consumer confidence has a moderating effect on the attitude and purchase intention. As it can be seen from the result of the analysis, it is necessary for municipal governments and the government to push ahead with the policies on organic farm products in the future as it is proved that there is a casual relationship among the attitude, purchase intention and the students' values of the organic farm products.