• Journal of Preventive Medicine and Public Health
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• v.38 no.1
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• pp.9-15
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• 2005

Objectives : To analyze medical expenses by cancer site and survival time among cancer patients in their last year of life. Method : The study subjects were 45,394 people that had died of cancers in 2002, were registered by the Korea Central Cancer Registry and received National Health Insurance benefit in the last year (360 days) of life. Personal identification data, general characteristics, dates of death and cancer incidence, and site of cancer were collected from the National Statistical Office and the Korea Central Cancer Registry, and merged with the data of the individual medical expenses of the Health Insurance Review Agency. Results : Average monthly cost curves were U-shaped with high costs near the time of diagnosis and death, and lower costs in between. Medical expenses in the last year of life were around 30.3, 16.7, 13.0, and 12.1 million won among leukemia, lymphoma, ovarian cancer, and breast cancer patients, respectively. Digestive organ cancers including stomach, esophagus, liver, pancreas, and colorectal cancers had relatively low medical expenses. Medical expenses in the last year of life were inverse U-shaped with high expenses near one year of survival. Average monthly cost in the 12 months before death among the patients who had survived $10{\sim}15$ years were more than two-fold greater than the cost before diagnosis among those who had survived for less than one year. Conclusions : Leukemia was the most expensive cancer. It is possible that once diagnosed as cancer, medical expenses do not return to the level before diagnosis. Further research will be needed to understand the magnitude and change of the medical expenses among cancer patients with long term follow up data.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.12 s.105
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• pp.1378-1388
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• 2005

Spatial control of sound is essential to deliver better sound to the listener's position in space. As it can be experienced in many listening environments. the quality of sound can not be manifested over every Position in a hall. This motivates us to control sound in a region we select. The primary focus of the developed method has to do with the brightness and contrast of acoustic image in space. In particular, the acoustic brightness control seeks a way to increase loudness of sound over a chosen area, and the contrast control aims to enhance loudness difference between two neighboring regions. This enables us to make two different kinds of zone - the zone of quiet and the zone of loud sound - at the same time. The other perspective of this study is on the direction of sound. It is shown that we can control the direction of perceived sound source by focusing acoustic energy in wavenumber domain. To begin with, the proposed approaches are formulated for pure-tone case. Then the control methods are extended to a more general case, where the excitation signal has broadband spectrum. In order to control the broadband signal in time domain, an inverse filter design problem is defined and solved in frequency domain. Numerical and experimental results obtained in various conditions certainly validate that the acoustic brightness, acoustic contrast, direction of wave front can be manipulated for some finite region in space and time.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.53-53
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• 2011

This paper describes results for surface and bulk characterization of the most promising thin film solar cell material for high performance devices, (Ag,Cu) (In,Ga) Se2 (ACIGS). This material in particular exhibits a range of exotic behaviors. The surface and general materials science of the material also has direct implications for the operation of solar cells based upon it. Some of the techniques and results described will include scanning probe (AFM, STM, KPFM) measurements of epitaxial films of different surface orientations, photoelectron spectroscopy and inverse photoemission, Auger electron spectroscopy, and more. Bulk measurements are included as support for the surface measurements such as cathodoluminescence imaging around grain boundaries and showing surface recombination effects, and transmission electron microscopy to verify the surface growth behaviors to be equilibrium rather than kinetic phenomena. The results show that the polar close packed surface of CIGS is the lowest energy surface by far. This surface is expected to be reconstructed to eliminate the surface charge. However, the AgInSe2 compound has yielded excellent atomic-resolution images of the surface with no evidence of surface reconstruction. Similar imaging of CuInSe2 has proven more difficult and no atomic resolution images have been obtained, although current imaging tunneling spectroscopy images show electronic structure variations on the atomic scale. A discussion of the reasons why this may be the case is given. The surface composition and grain boundary compositions match the bulk chemistry exactly in as-grow films. However, the deposition of the heterojunction forming the device alters this chemistry, leading to a strongly n-type surface. This also directly explains unpinning of the Fermi level and the operation of the resulting devices when heterojunctions are formed with the CIGS. These results are linked to device performance through simulation of the characteristic operating behaviors of the cells using models developed in my laboratory.

• Child Health Nursing Research
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• v.9 no.4
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• pp.432-440
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• 2003

Purpose: To provide basic data for strategy of substance abuse through the investigation of the status of substance abuse and knowledge and attitude about drugs in the elementary students. Method: Subjects were 565 6th grade of elementary students. Data were collected from June to July 2001 by using structured questionnaire. Result: 1) Among the students of respondents, 10.2% of them had the experience in smoking, 26.7% and 08% of them in drinking and inhalants, respectively. 2) The degree of students' knowledge about substance was 20.9 points on average with the highest score being 30. Students' knowledge about substances, smoking came on top, next came drinking and inhalants followed them. There were no significant differences in the knowledge of substances by general and drug related characteristics of the students. 3) The students' attitude about substances was negative with 30 points on average with the highest score being 108. As for the attitude about substances, they revealed the most generous in drinking next in smoking and inhalants. Those of boys, bored in school life and experienced in substance abuse were significantly generous in the attitude about substances. 4) There was a significant weak inverse relationship between the student's knowledge and attitude about substances (r=-0.13). As for the relationship between the student's knowledge and attitude about substances, the strongest relationship was shown in inhalants (r=-0.18) next in drinking (r=-0.16) and smoking (r=-0.06). Conclusion: The results of the finding suggest that the developing of programs in substance abuse for the elementary students are needed not only for the prevention but also for the cessation.

• Fire Science and Engineering
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• v.28 no.2
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• pp.69-75
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• 2014

This study derives the factors which affect the occurrence of arson from statistical data (population, economic, and social factors) by multiple regression analysis. Multiple regression analysis applies to 4 forms of functions, linear functions, semi-log functions, inverse log functions, and dual log functions. Also analysis respectively functions by using the stepwise progress which considered selection and deletion of the independent variable factors by each steps. In order to solve a problem of multiple regression analysis, autocorrelation and multicollinearity, Variance Inflation Factor (VIF) and the Durbin-Watson coefficient were considered. Through the analysis, the optimal model was determined by adjusted Rsquared which means statistical significance used determination, Adjusted R-squared of linear function is scored 0.935 (93.5%), the highest of the 4 forms of function, and so linear function is the optimal model in this study. Then interpretation to the optimal model is conducted. As a result of the analysis, the factors affecting the arson were resulted in lines, the incidence of crime (0.829), the general divorce rate (0.151), the financial autonomy rate (0.149), and the consumer price index (0.099).

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.2
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• pp.399-406
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• 2009

In this study, Polynomial Radial Basis Function Neural Network(pRBFNN) based on Fuzzy Inference System is designed and its parameters such as learning rate, momentum coefficient, and distributed weight (width of RBF) are optimized by means of Particle Swarm Optimization. The proposed model can be expressed as three functional module that consists of condition part, conclusion part, and inference part in the viewpoint of fuzzy rule formed in 'If-then'. In the condition part of pRBFNN as a fuzzy rule, input space is partitioned by defining kernel functions (RBFs). Here, the structure of kernel functions, namely, RBF is generated from HCM clustering algorithm. We use Gaussian type and Inverse multiquadratic type as a RBF. Besides these types of RBF, Conic RBF is also proposed and used as a kernel function. Also, in order to reflect the characteristic of dataset when partitioning input space, we consider the width of RBF defined by standard deviation of dataset. In the conclusion part, the connection weights of pRBFNN are represented as a polynomial which is the extended structure of the general RBF neural network with constant as a connection weights. Finally, the output of model is decided by the fuzzy inference of the inference part of pRBFNN. In order to evaluate the proposed model, nonlinear function with 2 inputs, waster water dataset and gas furnace time series dataset are used and the results of pRBFNN are compared with some previous models. Approximation as well as generalization abilities are discussed with these results.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.4
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• pp.393-398
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• 2015

A very important part in vibration analysis is to calculate the frequency response function (FRF). In general, a large sized or/and complicated structure has many thousands to millions of degrees. Therefore, the FRF cannot be calculated by the traditional analysis method using an inverse matrix. This paper presents a new FRF calculation method of a superstructure by synthesizing sub-structure modes, of which the DOF can be deduced by partitioning into some sub-structures. To confirm its analysis results, the method was applied to an assembled plate ($B300{\times}L900{\times}t5mm$) with three diagonal sub-plates($B300{\times}L300{\times}t5mm$) in series and compared with the measured data. The test results have were comparable those of the calculated ones with an error less than 5%.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.3
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• pp.172-176
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• 2010

Postirradiation extraosseous osteogenic sarcomas are uncommon in the head and neck, despite the extensive use of high-dose radiation. It has been described as de novo radiation-induced neoplasm. We present a 73-year-old male who had been treated by radiotherapy for gingival cancer 7 years earlier and later developed extraosseous osteogenic sarcomas (EOSs) of the neck. Microscopically, the neck mass was composed with mesenchymal malignant cells with cartilaginous and osteogenic differentiation. Immunohistochemical stain demonstrated strong positivity of tumor cells for Snail, the one of major epithelial-mesenchymal transition (EMT) inducer. The E-cadherin expression was scarce, showing inverse relationship to Snail expression. Compared with previous squamous cell carcinoma (SCC) of the gingiva, the present EOS sample revealed the remained epithelial cells on cytokeratin immunohistochemistry, suggesting the tumor arise from the cells of epithelial origin. We have also reviewed the previous 6 cases of head and neck EOSs carefully. The clinicopathologic features of the unusual lesion suggest that it is an incomplete EMT of precedent epithelial malignancy rather than de novo pathology.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.6
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• pp.125-132
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• 2008

Omnidirectional camera system with a wide view angle is widely used in surveillance and robotics areas. In general, most of previous studies on estimating a projection model and the extrinsic parameters from the omnidirectional images assume corresponding points previously established among views. This paper presents a novel omnidirectional camera calibration based on automatic contour matching. In the first place, we estimate the initial parameters including translation and rotations by using the epipolar constraint from the matched feature points. After choosing the interested points adjacent to more than two contours, we establish a precise correspondence among the connected contours by using the initial parameters and the active matching windows. The extrinsic parameters of the omnidirectional camera are estimated minimizing the angular errors of the epipolar plane of endpoints and the inverse projected 3D vectors. Experimental results on synthetic and real images demonstrate that the proposed algorithm obtains more precise camera parameters than the previous method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.6180-6189
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• 2015

The purpose of this study is to clarify the factors that affects smartphone addiction of elementary school students. The subjects were 263 students, from 4 elementary schools located in G-city. Data were collected from July, 2014 and analyzed using SPSS 19.0 program. The prevalence of addiction risk group and non-addicted group were 16.0% and 84.0%, respectively. The variables which had statistically significant differences with smart phone addiction of general characteristics are grade, living together family, economic status, school record, motivation for usage, advantage of usage and using time (p<.05). There was pure correlation between the smartphone addiction and impulsivity (r=.496, p<.001), daily stress (r=.471, p<.001). However, perceived parental attitude (r=-.375, p<.001) and self-esteem (r=-.444, p<.001) were inverse correlation with smartphone addiction. Higher using time, higher impulsivity and higher daily stress were all associated with increased of smartphone addiction level. These results suggest that more attentions should be given to early adolescents and could be effectively used as fundamental data to develop intervention programs, which can prevent the smartphone addiction.