• Title/Summary/Keyword: Multi-level regression analysis

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Human Multi-route Exposure Assessment of Lead and Cadmium for Korean Volunteers (일부 자원자를 통한 납, 카드뮴의 다경로 인체 노출평가)

  • Oh, Eun-Ha;Lim, Ho-Sub;Jang, Jae-Yeon;Lee, Eun-Il
    • Journal of Preventive Medicine and Public Health
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    • v.39 no.1
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    • pp.53-58
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    • 2006
  • Objectives: We wanted to evaluate the main route of exposure to lead and cadmium for the general population in Korea by using multi-route and multi-media exposure assessment Methods: Samples of air at the homes, samples of the food and water and peripheral blood samples were collected from thirty volunteers living in Seoul (the metropolitan area), Yong-in (the suburban area) and Ansan (the industrial area) in 2001. Graphite furnace atomic absorption spectrometric methods were used for the determination of the Pb and Cd levels in the air, food, water and blood samples. Results: The average intake of lead through the air, drinking water and food were $5.06{\mu}g/day\;(26.3%)\;0.002{\mu}g/day\;(0.1%),\;and\;16.4{\mu}g/day\;(73.6%)$, respectively. The average intake of cadmium through the air, drinking water and food were $0.082{\mu}g/day\;(0.9%),\;0.001{\mu}g/day\;(0.007%),\;and\;12.61 {\mu}g/day\;(99.0%)$, respectively. The blood lead level was statistically higher in the male subjects than in the female subjects (3.39 and $2.22{\mu}g/dl$, respectively), and only gender was a significant variable on the multiple regression analysis for blood lead. Conclusions: This study showed that the intake of lead and cadmium through food was the major route of exposure. A policy to reduce the pollutants according to the exposure routes should be established. However, more studies will be needed to support these data for the general population.

The Influence of Resident Satisfaction Regarding Buffer Green Space at Meoyng-ji Multi-family Housing in Busan Metropolitan City (부산광역시 명지주거단지 완충녹지가 거주생활 만족에 미치는 영향)

  • Yang, Geon-Seok
    • Journal of the Korean Institute of Landscape Architecture
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    • v.41 no.5
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    • pp.38-45
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    • 2013
  • Buffer green space in the residential area is a mechanism for improving the residential environment and also significant for residential life satisfaction and its various social roles. Accordingly, this study aimed to discover the effect of the buffer green space, which was established to minimize environmental influences of the residential environment, on residential life satisfaction. For this purpose, a survey was conducted on residents in Myeongji Residential Area where the buffer green space was installed, to examine the factors of the buffer green space and to analyze its causal relation with residential life satisfaction. The SPSS(statistical package for social science) 21 program was used for analysis and factorial analysis, correlation analysis and multiple regression analysis were executed. As a result, the roles of the buffer green space in Myeong-ji Residential Area included residential comfort, disaster protection, green space usability and environmental ecological property. In the overall accrued factorial contribution rate, residential comfort was very high with 40.54% out of total 62.48%. In addition, the residential comfort and green area usability had a higher correlation with residential life satisfaction. However, the significant level of disaster protection and environmental ecological property were 0.725 and 0.898, respectively, which were not significant as a preference factor in multiple regression analysis. Accordingly, the buffer green space for improving residential comfort and green space usability was confirmed to enhance residential life satisfaction.

The Effect of Community- and Individual-Level Factors on Suicidal Ideation and Attempts: A Multilevel Analysis (2021년 지역사회건강조사를 활용한 지역사회 및 개인 수준의 요인이 자살 생각과 자살 시도에 미치는 영향: 다수준 분석)

  • So Young Ha;Jinhwan Kim;Haegyun Park;Youngsoo Kim
    • Korean Journal of Psychosomatic Medicine
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    • v.32 no.1
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    • pp.24-33
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    • 2024
  • Objectives : The purpose of this study was to investigate individual- and community-level factors on suicidal ideation and suicide attempt among Korean adults. Methods : This study was conducted on 225,965 adults collected through data from the 2021 Community Health Survey and the Korean Statistical Information Service (KOSIS). The general characteristics, suicidal behavior (e.g., suicidal ideation, and suicide attempts), and community-level characteristics of the study subjects were analyzed using frequency (%) and mean (standard deviation). The effects on individual- and community-level factors on suicidal ideation and suicide attempts was analyzed using multilevel logistic regression models. Results : The community-level factor associated with suicidal ideation was unmet health care (Odds Ratio [OR]=1.053, 95% CI=1.035-1.071), and the community-level factor associated with suicide attempt was the aging rate (OR=1.015, 95% CI=1.001-1.030). Regarding health-related variables, the individual-level factors associated with suicidal ideation were stress status (OR=9.388, 95% CI=8.629-10.213), depressive experience in the past year (OR=6.737, 95% CI=6.454-7.032), and the predominantly individual-level factors associated with suicide attempt were also stress status (OR=5.213, 95% CI=3.699-7.347), and depressive experience in the last one year (OR=13.433, 95% CI: 11.247-16.044). Conclusions : We confirmed individual-level and community-level factors influencing suicidal ideation and suicide attempt. Through these findings, we need to establish suicide prevention policies, considering managing individual-level factors such as stress and depression as well as community-level factors such as unmet health care.

The Effects of Compliance Timing on Multinational Enterprises' Corporate Performance in China: An Application of Institutional Perspectives

  • Yang, Woo-Young;Han, Byoung-Sop
    • Journal of Korea Trade
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    • v.24 no.4
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    • pp.71-94
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    • 2020
  • Purpose - Multi-National Enterprises (MNEs) tend to face a high level of institutional pressures in regions with high institutional development level. When complying with institutional pressures, firms try to make decisions to maximize profit while minimizing the risks to them. The purpose of this study is to investigate the influence of the institutional development level on institutional compliance timing by MNEs and the relationship between compliance speed and corporate performance. Design/methodology - The research focuses on three main variables, which are the institutional development level (as a determination of the institutional pressure level), the firm's compliance speed (as a determination of the compliance timing), and the firm's financial performance (as a determination of the corporate performance). We collected 19,869 firm-level data from CSMAR (the China Stock Market and Accounting Research), 6,922 CSR data from RKS (the Rankins CSR Ratings), and province and city-level data from the NERIM (National Economic Research Institute Index of Marketization) and NBSC (National Bureau of Statistics of China). The firms in China were chosen for analysis, and the analysis period was from 2008 to 2017. Random Effects GLS Regression was used to test the relationships among the variables. Findings - This study examined the effect of the institutional development level on the firm's compliance speed, together with the effect of compliance speed on the firm's financial performance of the MNEs in China. We found that the institutional development level positively influenced firms' financial performances, which means the firms' financial performances are better in the region with a high institutional development level. The compliance speed of institutional practice by firms was faster in the higher level of institutional development. However, the firm's delayed compliance led to better financial performance. Originality/value - Studies in the resource dependence view of Institutional Theory often fall short in understanding the theory by overlooking the firm's active decision-making. Thus, the findings do not present a full scope of corporate performance in this regard. This study not only found a way to test the role of a firm's independent decision-making (i.e., compliance timing) when facing the institutional pressure but also prove the significant role of the compliance timing on corporate performance. Also, we were able to test the effect of institutional development level, controlling location-specific variables because we used CSR performance data for MNEs operating in China. Lastly, by doing the above, the findings of this study suggest practical implications to the industry practitioners in MNEs.

A Cross-Cultural Investigation of Adults' Formation of Sense of Community through Environmental Autobiography

  • Kim, Wonpil
    • Architectural research
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    • v.14 no.4
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    • pp.125-132
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    • 2012
  • In contemporary Korean society, urban community environment is often associated with high-density and high-rise residences that make people's relationships superficial, instrumental and impersonal. Furthermore, urban community consistently interplays with neighboring residents and childhood emotional experience are influential on their unconscious images and attitude about their current neighborhood environment, while affecting the environmental attitude and the formation of community sense. Previous research found evidences that increased level of community sense is fostering more feeling of living in so-called "real neighborhood environment." This study aimed to cross-culturally examine what the respondents' emotional perception and their attitude were about the community environment in their childhood through environmental autobiography method and to examine the effects of the results on adults' formation of sense of community for their current community environment. Extensive literature review explored a few important theoretical framework which are closely related to sense of community (SOC) as a result of emotional experience: membership, influence, integration and fulfillment of needs, shared emotional connection and community satisfaction. Chi-square and GLM analysis revealed that there were no demographic, and socio-economic differences between two groups of Korean and US residents. Correlation analysis indicated that childhood emotional experience of Koreans and US citizens was statistically significant on sense of community for their current living community. Multi-regression analysis also found that the degree of influence were the main predictors for building strong sense of current community throughout a cross-cultural group. Furthermore, the relationship between various emotional experience of each factor in previous and current community environment were statistically significantly related. It is concluded that as the positive childhood experience of influence in their past community was going up, the level of sense of community for their current community was strengthened across their cross-cultural background.

Improvement of the Accuracy of Wrist Noninvasive Blood Pressure Measurement Using Multiple Bio-signals (다중 생체 신호를 통한 손목 혈압 측정의 정확도 향상)

  • Jung, Woon-Mo;Sim, Myeong-Heon;Jung, Sang-O;Kim, Min-Yong;Yoon, Chan-Sol;Jung, In-Chol;Yoon, Hyung-Ro
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.8
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    • pp.1606-1616
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    • 2011
  • The blood pressure measuring equipment, which is being supplied and used most widely by being recognized convenience and accuracy now generally, is oscillometric blood pressure monitor. However, a change in blood pressure is basically influenced by diverse elements such as each individual's physiological status and physical condition. Thus, the measurement of blood pressure, which used single element called oscillation in blood pressure of being conveyed to cuff, is not considered on physiological elements such as cardiovascular system status and blood vessel stiffness index, and on external elements, thereby being quite in error. Accordingly, this study detected diverse bio-signals and body informations in each individual as the measurement subject such as ECG, PPG, and Korotkoff Sound in order to enhance convenience and accuracy of measuring blood pressure in the complex measurement equipment, thereby having extracted regression method for compensation in error of oscillometric blood pressure measurement on the wrist, and having improved accuracy of measuring blood pressure. To verify a method of improving accuracy, the blood pressure value in each of SBP, DBP, MAP was acquired through 4-stage experimental procedure targeting totally 51 subjects. Prior to experiment, the subjects were divided into two groups such as the experimental group for extracting regression method and the control group for verifying regression method. Its error was analyzed by comparing the reference blood pressure value, which was obtained through the auscultatory method, and the oscillometric blood pressure value on the wrist. To reduce the detected error, the blood pressure compensation regression method was calculated through multiple linear regression analysis on elements of blood pressure, individual body information, PTT, HR, K-Sound PSD change. Verification was carried out on improving significance and accuracy by applying the regression method to the data of control group. In the experimental results, as a result of confirming error on the reference blood pressure value in SBP, DBP, and MAP, which were acquired through applying regression method, the results of $-0.47{\pm}7.45$ mmHg, $-0.23{\pm}7.13$ mmHg, $0.06{\pm}6.39$ mmHg could be obtained. This is not only the numerical value of satisfying the sphygmomanometer reference of AAMI, but also shows the lower result than the numerical value in SBP : $-2.5{\pm}12.2$ mmHg, DBP : $-7.5{\pm}8.4$ mmHg, which is the mean error in the experimental results of Brram's research for verifying accuracy of Omron RX-M, which shows relatively high accuracy among wrist sphygmomanometers. Thus, the blood pressure compensation could be confirmed to be made within significant level.

Submarket Identification in Property Markets: Focusing on a Hedonic Price Model Improvement (부동산 하부시장 구획: 헤도닉 모형의 개선을 중심으로)

  • Lee, Chang Ro;Eum, Young Seob;Park, Key Ho
    • Journal of the Korean Geographical Society
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    • v.49 no.3
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    • pp.405-422
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    • 2014
  • Two important issues in hedonic model are to specify accurate model and delineate submarkets. While the former has experienced much improvement over recent decades, the latter has received relatively little attention. However, the accuracy of estimates from hedonic model will be necessarily reduced when the analysis does not adequately address market segmentation which can capture the spatial scale of price formation process in real estate. Placing emphasis on improvement of performance in hedonic model, this paper tried to segment real estate markets in Gangnam-gu and Jungrang-gu, which correspond to most heterogeneous and homogeneous ones respectively in 25 autonomous districts of Seoul. First, we calculated variable coefficients from mixed geographically weighted regression model (mixed GWR model) as input for clustering, since the coefficient from hedonic model can be interpreted as shadow price of attributes constituting real estate. After that, we developed a spatially constrained data-driven methodology to preserve spatial contiguity by utilizing the SKATER algorithm based on a minimum spanning tree. Finally, the performance of this method was verified by applying a multi-level model. We concluded that submarket does not exist in Jungrang-gu and five submarkets centered on arterial roads would be reasonable in Gangnam-gu. Urban infrastructure such as arterial roads has not been considered an important factor for delineating submarkets until now, but it was found empirically that they play a key role in market segmentation.

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Development of Growth Model Using Ecological Momentary Assessment: Based on Senior Vitality Quotient (생태순간평가를 이용한 성장모형개발: 노년 활력 지수를 활용하여)

  • Jeon, Hee Jin;Song, Hye Sun;Lee, Ji Hyun;Park, Kiho;Choi, Kee-Hong;Seo, Dong Gi
    • Journal of the Korea Convergence Society
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    • v.12 no.5
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    • pp.313-326
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    • 2021
  • This study was to introduce ecological momentary assessment and show how to apply it to real-world research. As preliminary study for sustainable development, the result explained growth model using senior's longitudinal data and suitability of multi-level model in EMA data with regression analysis. The total variance of dependent variable was determined through a base model with only intercept and approximately 47% of total variance was caused by individual differences and 53% by time point differences. Second model was used to verified that each individual has a different effect on the senior vitality and effect on time was not significant. This is because it is the result of a preliminary stage where treatment is not involved and there is no significant change in process of collecting EMA data without external intervention. Third model that add gender as an independent variable showed significant change in both time and gender. Finally compared the PRD for each model and found models that without gender variables fit the data more effectively. This suggests that studies dealing with longitudinal data such as EMA data should adopt multi-level model that can measure individual characteristics, taking into account respondents' time and context.

A Study on Influences of the Characteristics of Medical Consumers' Words-Transmission Information to its Acceptance Level and its Activities (의료소비자의 구전정보특성이 구전수용수준과 구전활동에 미치는 영향에 관한 실증적 연구)

  • Kang, Soo-Won;Shim, Wan-Sop
    • Korea Journal of Hospital Management
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    • v.3 no.1
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    • pp.192-218
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    • 1998
  • This study is the positive one about the influence which the characteristics of medical consumers' perceived words-transmission information exercises on its acceptance level and its activities. The aim of this study was to investigate how the characteristics-reliability of perceived information, its directionity, and its availability-had an influence on the acceptance level and activities of words-transmission information. For the purpose of that aim, the positive research by questionnaire was applied. In addition, to collect necessary data, investigation was performed about 20 days from July 1st, 1938 to July 20th, 1938. As for the respondents' sampling in sample planning, the method of Simple Random Sampling was used laying stress on patients or their responsible person aged over 20s in second and third medical institutions. And the collected sample were 230 people. Of these, However, the number of sample used actually for this study analysis was 211 except 19 people who responded unfaithfully. The analysis of the data collected by the abovesaid investigation used SPSS/PC statistical package. The study result to have proved the hypothesis by experiment is as follows. First, as the result of having analysed the influence relations on the acceptance level and activities of words-transmission information among the factors of reliability about medical consumers' perceived information, I found that 'specialty' had an affirmative effect and there was a significant effect relations. Second, as the result of having made a multi-regression analysis of the effect relations on the acceptance level and activities of words-transmission information of the factors of directionity on medical consumers' perceived information, 'reliablity' was found as having a significant effect on the acceptance of words-transmission information. Third, 'importantness' was revealed as having a significant effect on the words-transmission activities in the acceptance level and activities of words-transmission information among the factors of reliability on medical consumers' perceived information. Fourth. for medical consumers there was a statistical correlation between the acceptance level and activities of words-transmission information. Therefore, words-transmission communication will be very useful for hospital promotion programs having a limited advertising ability in business. Especially, I suggest that a person in charge of his/her hospital marketing should not only excavate a source of words-transmission communication in order to arrive effectively at sampling market, but also use a marketing mix suitable to that The test result shows that the unsatisfied patients over their hospital treatment tend to be more stronger in transmitting words to the other positive minded patients than the satisfied ones. Therefore, all relating representatives in hospital should concentrate their energies on decreasing or eliminating these unwanted results.

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Operation analysis and application of modified slope-area method for the estimation of discharge in multi-function weir (다기능보의 방류량 산정 개선을 위한 운영 분석 및 수정 경사-면적법의 적용)

  • Oh, Ji-Hwan;Jang, Suk-Hwan;Oh, Kyoung-Doo
    • Journal of Korea Water Resources Association
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    • v.51 no.8
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    • pp.687-701
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    • 2018
  • A multi-function weir is representative control structure in the stream flow. Estimation of accurate flood discharge according to gate operations and prediction of floodwave travel times at the downstream are very important in terms of water use and river management. This study analyzed the limitation and improvement through the current gate operation data on the Young-san river. in addition, flood discharge was calculated considering lower and upper water level condition and gate operating using the modified slope-area method in the Seoung-chon weir. As a result, the current state was required improvement because exceed the theoretical range and rapidly fluctuation of discharge coefficient, can not be considered difference between the upper and lower water level and the estimation by the regression equation. As a result of applying the proposed method in this study, the above mentioned limitations can be compensated, compared with the current discharge data. Also it was analyzed as more physically valid because using the evaluated hydraulic equation and estimate the slope and friction loss of natural stream by iteration and to reduce the error. In conclusion, the process carried out serves as a representative flow control point of the water system through reliable discharge estimation, it is expected that it will be possible to properly river management.