• Journal of environmental and Sanitary engineering
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• v.17 no.4
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• pp.61-67
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• 2002

NIRS(Near infrared spectroscopy) scanning from 1300nm to 2400nm was appl ied for the DEHP(di-(2 ethylhexyl)phthalate) in PVC(polyvinyl chloride_packing material. All samples were devided into calibration group and validation group. As a result of conduction the multiple regression analysis on the correlation between the NIR spectrum data and chemical assay value obtained by the Korea Food Sanitation Act. The validation model for measuring the DEHP content had R of 0.997, SEC of 0.132, SEP of 0.176 by MLR and R of 0.996, SEC of 0.142, SEP of 0.198 by PLS and the detection limit was 0.1%. The obtained results indicate that the NIR procedure can potentially be used as a nondestructive analysis method for the purpose of rapid and simple measurement of DEHP in PVC packing material.

• International Journal of Advanced Culture Technology
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• v.10 no.2
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• pp.213-219
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• 2022

This study tried to find various alternatives to live the rest of life positively by examining whether satisfaction with work in old age has a positive effect on psychological adjustment in old age. Using the 15th (2020) data of the Korea Welfare Panel Study (KOWEPS), 117 men and 355 women were analyzed as a sample to verify the effect of job participation satisfaction among the elderly on psychological adjustment. The results of the regression analysis in this paper (F=11.680, p<.001) were analyzed to be significant. The results showed gender (β=-.192, p<.001), age (β=2.004, p<.001), and job participation satisfaction (β=-3.726, p<.001). Therefore, it was found to have an effect on psychological adaptation. In terms of gender, it was found that men had higher psychological adaptability than women, and that the lower the age, the higher the psychological adaptability. As a result, it was confirmed that the elderly's job participation is a simple economic part of the elderly, and the psychologically positive influence increased. The higher the job participation satisfaction, the higher the psychological adaptability.

• International Journal of Advanced Culture Technology
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• v.11 no.4
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• pp.123-130
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• 2023

The purpose of this study was to find out how tennis participants' participation affects their optimism and aggression. A total of 249 (male: 163, female: 86) subjects were studied. The Revised Life Orientation Test (LOT-R) developed by Scheier, Carver, and Bridges (1994) was used as an optimism test, and the Aggression Questionnaire developed by Buss and Perry (1992) was used as an aggressiveness test. As data analysis methods, one-sample t-test, Pearson's correlation analysis, and simple regression analysis were performed. As a result, first, those who participate in tennis were more optimistic than those who do not. Second, those who participate in tennis were less aggressive than those who do not. Third, optimism affects physical aggression, anger and hostility negatively

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.4805-4811
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• 2013

The purpose of this study is to analyse the satisfaction level and psychological status of senior students of "Silver College," or seniors' college. For the analysis, questionnaire survey was conducted to senior students of Silver Colleges of B and K University in Busan from May 1 through 31, 2013. The analysis methods used are SPSS Win 18.0 program on analysis of frequency, one-way analysis of variance, a correlation analysis, simple regression analysis and multiple regression analysis, with analysis of actual proof for 5% significance level. The result of analysis indicates that the senior students' satisfaction level rose and serious physical symptoms improved after taking silver college programs from before. This study is significant in that it provides theoretical grounds for increasing the number of silver colleges with professional and socially-renowned professors as faculty, and developing further programs and policies for the solution of aggravating physical and mental problems more and more senior people are faced with in this fast aging society.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.9 s.114
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• pp.897-903
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• 2006

The reduction of the vehicle interior noise has been the main interest of noise and vibration harshness (NVH) engineers. The driver's perception on the vehicle noise is affected largely by psychoacoustic characteristic of the noise as well as the SPL. In particular, the heating, ventilation and air conditioning (HVAC) system sound among the vehicle interior noise has been reflected sensitively in psychoacoustics view point. Even though the HVAC noise is not louder than overall noise level, it clearly affects subjective perception to drivers in the way of making to be nervous or annoyed. Therefore, these days a vehicle engineer takes aim at developing sound quality as well as reduction of noise. In this paper, we acquired noises in the HVAC from many vehicles. Through the objective and subjective sound quality (SQ) evaluation with acquiring noises recorded by the vehicle HVAC system, the simple and multiple regression models were obtained for the subjective evaluation 'Pleasant' using the semantic differential method (SDM). The regression procedure also allows you to produce diagnostic statistics to evaluate the regression estimates including appropriation and accuracy. Furthermore, the neural network (NN) model were obtained using three inputs(loudness, sharpness and roughness) of the SQ metrics and one output(subjective 'Pleasant'). Because human's perception is very complex and hard to estimate their pattern, we used NN model. The estimated models were compared with correlations between output indexes of SQ and hearing test results for verification data 'Pleasant'. As a result of application of the SQ indexes, the NN model was shown with the largest correlation of SQ indexes and we found possibilities to predict the SQ metrics.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1443-1448
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• 2006

The reduction of the vehicle interior noise has been the main interest of NVH engineers. The driver's perception on the vehicle noise is affected largely by psychoacoustic characteristic of the noise as well as the SPL. In particular, the HVAC sound among the vehicle interior noise has been reflected sensitively in the side of psychology. Even though the HVAC noise is not louder than overall noise level, it clearly affects subjective perception in the way of making a diver become nervous or annoyed. Therefore, these days a vehicle engineer takes aim at developing sound quality as well as reduction of noise. In this paper, we acquired noises in the HVAC from many vehicles. Through the objective and subjective sound quality evaluation with acquiring noises caused by the vehicle HVAC system, the simple and multiple regression models were obtained for the subjective evaluation 'Pleasant' using the sound quality metrics. The regression procedure also allows you to produce diagnostic statistics to evaluate the regression estimates including appropriation and accuracy. Furthermore, the neural network model were obtained using three inputs(loudness, sharpness and roughness) of the sound quality metrics and one output(subjective 'Pleasant'). And then the models were compared with correlations between sound quality index outputs and hearing test results for 'Pleasant'. As a result of application of the sound quality index, the neural network was verified with the largest correlation of the sound quality index.

• Toxicological Research
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• v.30 no.1
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• pp.7-11
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• 2014

Malondialdehyde (MDA), used as an oxidative stress marker, is commonly assayed by measuring the thiobarbituric acid reactive substances (TBARS) using HPLC, as an indicator of the MDA concentration. Since the HPLC method, though highly specific, is time-consuming and expensive, usually it is not suitable for the rapid test in large-scale environmental epidemiologic surveys. The purpose of this study is to develop a simple and rapid method for estimating TBARS levels by using a multiple regression equation that includes TBARS levels measured with a microplate reader as an independent variable. Twelve hour urine samples were obtained from 715 subjects. The concentration of TBARS was measured at three different wavelengths (fluorescence: ${\lambda}-_{ex}$ 530 nm and ${\lambda}-_{em}$ 550 nm; ${\lambda}-_{ex}$ 515 nm and ${\lambda}-_{em}$ 553 nm; and absorbance: 532 nm) using microplate reader as well as HPLC. 500 samples were used to develop a regression equation, and the remaining 215 samples were used to evaluate the validity of the regression analysis. The induced multiple regression equation is as follows: TBARS level (${\mu}M$) = -0.282 + 1.830 ${\times}$ (TBARS level measured with a microplate reader at the fluorescence wavelengths ${\lambda}-_{ex}$ 530 nm and ${\lambda}-_{em}$ 550 nm, ${\mu}M$) -0.685 ${\times}$ (TBARS level measured with a microplate reader at the fluorescence wavelengths ${\lambda}-_{ex}$ 515 nm and ${\lambda}-_{em}$ 553 nm, ${\mu}M$) + 0.035 ${\times}$ (TBARS level measured with a microplate reader at the absorbance wavelength 532 nm, ${\mu}M$). The estimated TBARS levels showed a better correlation with, and are closer to, the corresponding TBARS levels measured by HPLC compared to the values obtained by the microplate method. The TBARS estimation method reported here is simple and rapid, and that is generally in concordance with HPLC measurements. This method might be a useful tool for monitoring of urinary TBARS level in environmental epidemiologic surveys with large sample sizes.

• The Journal of Industrial Distribution & Business
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• v.9 no.12
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• pp.31-43
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• 2018

Purpose - Smartphone shopping malls provide customers with a variety of tangible and intangible services including web sites, web design, use convenience, information for products and shopping and various after services. Accordingly, it is needed to expand and classify service qualities based on the various services provided by smartphone shopping malls, and then analyze path structures of smartphone shopping malls' qualities → customer satisfaction → behavioral intention. The purpose of this study is to categorize the qualities of smartphone shopping mall users based on the e-SERVQUAL by Lee(2002) and the SERVQUAL by Parasuraman et al.(1988, 2005), the smartphone shopping malls' service qualities based on service quality of smartphone shopping malls used in the previous use studies, and the Website quality factors of service industry and to analyze path structure of smartphone shopping mall's qualities → customer satisfaction → behavioral intention on college students in order to confirm the system of smartphone shopping malls' qualities. Research design, data, and methodology - This study's survey was carried out on the college students of university located in northeastern of Seoul. It was from December 7 - 15, 2017, and a total of 240 questionnaires were distributed, with 228 collected. Of them, effective questionnaires used in the final study were a total of 201 except 27 that couldn't be used. In this study, empirical analysis was done with factor analysis, correlation analysis, multiple regression analysis, simple multiple regression analysis and moderating regression analysis by using Statistics Package SPSS18.0. Results - The study results are as follows: First, smartphone shopping malls' qualities were classified into six categories like customer system quality, Web design quality, convenience quality, information-offering quality, service quality, and product quality. Second, it showed that system quality, Web design quality, and information-offering quality had a positive impact on customer satisfaction, respectively. Third, it suggested that quality factors of smartphone shopping mall users had a positive impact on customer satisfaction in the order of quality, information-offering quality, system quality and Web design quality. Finally, it showed that customer service quality, product quality, and convenience quality did not have a positive impact on customer satisfaction. In addition, it said that customer satisfaction of smartphone shopping mall users had a positive impact on behavioral intention and thereby, the higher the customer satisfaction was, the higher the relations between reuse intention and recommendation intention were. Meanwhile, moderating regression analysis showed that trust did not have moderating effect in the relations between customer satisfaction and behavioral intention. The above study revealed that smartphone shopping malls' qualities were classified into six categories and it was possible to generalize after empirical analysis was made in the path structure. Conclusions - Smartphone shopping mall users consider usefulness of obtaining shopping information and quality on quick and abundant shopping information more important than access environment of smartphone shopping malls and kind services of smartphone shopping mall managers. Thereby, smartphone shopping mall marketers need to take service qualities like system quality and information-offering quality into more consideration.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.5
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• pp.273-278
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• 2019

In this study, a new simple method for the estimation of hyperelastic material properties by indentation tests is proposed. Among hyperelastic material models, the Yeoh model with three material properties ($C_{10}$, $C_{20}$, $C_{30}$) is adopted to describe the strain energy density in terms of strain invariants. Finite element simulations of the spherical indentation of hyperelastic materials of the Yeoh model with different material properties are performed to establish a database of indentation force-displacement curves. The indentation force-displacement curves are fitted by cubic polynomials, which are approximated as a product of third-order polynomials of ($C_{10}$, $C_{20}$, $C_{30}$). A regression analysis is conducted to determine the coefficients of the equations for the indentation force-displacement curve approximations. A regression equation is used to estimate the hyperelastic material properties. The present method is verified by comparing the estimated material properties with true values.

• Journal of Korean Society on Water Environment
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• v.29 no.6
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• pp.832-841
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• 2013

In recent years, eutrophication in the Paldang Lake has become one of the major environmental problems in Korea as it may threaten drinking water safety and human health. Thus it is important to understand the phenomena and predict the time and magnitude of algal blooms for applying adequate algal reduction measures. This study performed seasonal water quality assessment and chlorophyll-a prediction using Bayseian simple/multiple linear regression analysis. Bayseian regression analysis could be a useful tool to overcome limitations of conventional regression analysis. Also it can consider uncertainty in prediction by using posterior distribution. Generally, chlorophyll-a of a P2(Paldang Dam 2) site showed high concentration in spring and it was similar to that of P4(Paldang Dam 4) site. For the development of Bayseian model, we performed seasonal correlation. As a result, chlorophyll-a of a P2 site had a high correlation with P5(Paldang Dam 5) site in spring (r = 0.786, p<0.05) and with P4 in winter (r = 0.843, p<0.05). Based on the DIC (Deviance Information Criterion) value, critical explanatory variables of the best fitting Bayesian linear regression model were selected as a $PO_4-P$ (P2), Chlorophyll-a (P5) in spring, $NH_3-N$ (P2), Chlorophyll-a (P4), $NH_3-N$ (P4) in summer, DTP (P2), outflow (P2), TP (P3), TP (P4) fall, COD (P2), Chl-a (P4) and COD (P4) in winter. The results of chlorophyll-a prediction showed relatively high $R^2$ and low RMSE values in summer and winter.