• Title/Summary/Keyword: Multi linear regression analysis

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Body Mass Index Compared with Waist Circumference Indicators as a Predictor of Elevated Intraocular Pressure (안압상승의 위험인자로서 체질량지수(BMI)와 허리둘레의 비교)

  • Park, Sang-Shin;Lee, Eun-Hee;Paek, Domyung;Cho, Sung-Il
    • Journal of Korean Ophthalmic Optics Society
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    • v.15 no.3
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    • pp.293-297
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    • 2010
  • Purpose: The aim of the current study was to compare body mass index (BMI) with waist circumference (WC) as a predictor of elevated intraocular pressure (IOP). Methods: The subjects were consisted of 458 adults, aged 20 year or above, of one community in Kyunggi-do. Mean IOPs were stratified jointly for BMI and WC tertiles. Multi-variate linear regression analysis was also used to compare between BMI and WC. Results: Although any BMI tertiles were not associated with IOP within each tertile of WC, WC tertiles was significantly related to elevation of IOP within the third BMI tertile (${\geq}24.9kg/m^2$). After adjusting for age and sex, only WC showed significant association with IOP. In additional adjustment for lifestyle variables, both BMI and WC were significantly associated with elevation of IOP. However, the results showed the stronger association of IOP with WC than BMI, whether they were adjusted by age and sex or additionally lifestyle variables. Conclusions: These data showed that BMI and WC were positively associated with IOP. However, WC appeared to be a better indicator for higher IOP than BMI.

A STUDY OF SPATIAL ABILITY AND WINDOW PRESENTATION STYLES IN WEB-BASED INSTRUCTION (웹 기반 학습에 있어서 공간 지각력과 정보제공 창의 형태 간의 관계 분석)

  • Im, Yeon-Wook
    • Journal of The Korean Association of Information Education
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    • v.9 no.4
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    • pp.649-659
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    • 2005
  • A window presentation style, either tiled window or single page design, determines the spatial arrangement of information in a modern computer-based instructional design. This study investigates the interaction between spatial ability and window presentation style in terms of student's achievement of cognitive knowledge through Web-based instruction. Seventy-one students from the Falk School in Pennsylvania were pre-tested to determine their level of spatial ability, then randomly divided into two treatment groups in order to study a Web-based instructional unit on flowering plants. The Web-based instructional package was organized with either tiled window presentation or single page presentation. A posttest measured participants'acquisition of the instructional content. Posttest and spatial ability test scores were analyzed using multi-variate linear regression for the full sample (n=71) and three sub-samples: (a) 4th and 5th grade students only, (b) female students only, and (c) 4th and 5th grade female students only. The goals of the data analysis included the examination of (i) the correlation between spatial ability and posttest scores; (ii) the correlation between window presentation style and posttest score; and (iii) the interaction between spatial ability (aptitude) and presentation style (treatment).The data from all four sample groups showed a significant relationship between spatial ability and achievement of cognitive knowledge at the 1% level of significance. The aptitude-treatment interaction between spatial ability and style of window presentation was not significant in the full sample, but was significant in the sub-samples either at the 10% or 5% level. In neither the full sample nor any sub-sample data did window presentation style have an impact on average posttest score. In all analyses, the higher the level of spatial ability, the higher the posttest score. The sub-samples revealed that students with low spatial ability performed better with the tiled window presentation, while those with high spatial ability did better with the single page presentation. Neither window presentation style was shown to better foster learning by children of all levels of spatial ability.

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Some Factors Affecting Profitability of Local Public Hospitals (지방의료원의 재무성과 영향요인)

  • Park, Jong-Young
    • Korea Journal of Hospital Management
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    • v.12 no.3
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    • pp.47-67
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    • 2007
  • This paper aims at suggesting several ways lo change financial vulnerability and to improve managerial capability of local public hospitals (LPHs) in Korea through the identification of factors affecting profitability. Several findings of the research are as follows: To begin with, LPHs exhibited a statistically significant difference in their profitability from one another, according to tile analyses of their profitable margins from tile general characteristics. It depends on the number of hospitals in the area, the population of the hospital-built area, the number of competing hospitals, the number of staff per 100 beds, the opening of special clinic, the educational function, and the capacity of rooms. However, there was no variable in the managerial characteristics, presenting a significant difference, in contrast with hospitals which have been managed by private companies and made a great amount of profits. Second, according to the analyses of profit differences in behavioral effort-characteristics, a statistically significant difference was revealed upon the basis of the efforts to improve the clinic service, invite special patients, and shorten the period of being hospitalized. Third, the result of analyses about the difference of profitability from medical care and finance is statistically significant in the rate of labor cost, the rate of management cost, bed-occupancy rate, and the period of being hospitalized. Fourth, according to the analyses of the factors influencing the net profit ratio of the entire capital, Adjusted explanatory power(Adjusted $R^2$) was shown up to 65.2%, which is high. To compare the adjusted explanatory power stage by stage, the first stage model applying only two variables such as structural and strategic characteristics exhibited 23.8%, and the second stage model adding financial characteristics showed 51.5%. The explanatory power was much improved up to 65.2% when the third stage model incorporated the outcome of medical care performance. When the return on investment(ROI) was examined by using the multi-variate linear regression analysis at the final model of third stage, it was found that ROI had a positive relationship with the increase rate of patients, labor costs per doctor, and medical care rate of socially protected inpatients. However, it revealed that ROI had a negative relationship with the ratio of labor costs, the number of patients per managerial staff, and occupancy rate of rooms, respectively. The research suggests that in order for LPHs to increase profitability, LPH, should make efforts not only to attract patients to the hospitals without any discrimination of the patients depending on their financial status, but also to develop efficient management methods to reduce labor costs.

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How to Avoid Graft-Tunnel Length Mismatch in Modified Transtibial Technique for Anterior Cruciate Ligament Reconstruction Using Bone-Patellar Tendon-Bone Graft

  • Ko, Dukhwan;Kim, Hyeung-June;Oh, Seong-Hak;Kim, Byung-June;Kim, Sung-Jae
    • Clinics in Orthopedic Surgery
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    • v.10 no.4
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    • pp.407-412
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    • 2018
  • Background: We conducted this study to determine the optimal length of patellar and tibial bone blocks for the modified transtibial (TT) technique in anterior cruciate ligament (ACL) reconstruction using the bone-patellar tendon-bone (BPTB) graft. Methods: The current single-center, retrospective study was conducted in a total of 64 patients with an ACL tear who underwent surgery at our medical institution between March 2015 and February 2016. After harvesting the BPTB graft, we measured its length and that of the patellar tendon, patellar bone block, and tibial bone block using the arthroscopic ruler and double-checked measurements using a length gauge. Outcome measures included the length of tibial and femoral tunnels, inter-tunnel distance, length of the BPTB graft, patellar tendon, patellar bone block, and tibial bone block and graft-tunnel length mismatch. The total length of tunnels was defined as the sum of the length of the tibial tunnel, inter-tunnel distance and length of the femoral tunnel. Furthermore, the optimal length of the bone block was calculated as (the total length of tunnels - the length of the patellar tendon) / 2. We analyzed correlations of outcome measures with the height and body mass index of the patients. Results: There were 44 males (68.7%) and 20 females (31.3%) with a mean age of 31.8 years (range, 17 to 65 years). ACL reconstruction was performed on the left knee in 34 patients (53%) and on the right knee in 30 patients (47%). The optimal length of bone block was 21.7 mm (range, 19.5 to 23.5 mm). When the length of femoral tunnel was assumed as 25 mm and 30 mm, the optimal length of bone block was calculated as 19.6 mm (range, 17 to 21.5 mm) and 22.1 mm (range, 19.5 to 24 mm), respectively. On linear regression analysis, patients' height had a significant correlation with the length of tibial tunnel (p = 0.003), inter-tunnel distance (p = 0.014), and length of patellar tendon (p < 0.001). Conclusions: Our results indicate that it would be mandatory to determine the optimal length of tibial tunnel in the modified TT technique for ACL reconstruction using the BPTB graft. Further large-scale, multi-center studies are warranted to establish our results.

Factors Affecting Emotional Labor among Physical Therapists and Occupational Therapists (물리치료사 및 작업치료사의 감정노동 수준에 미치는 요인)

  • Hur, Yoon-Jung;Lee, Suk-Min
    • Journal of the Korea Convergence Society
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    • v.10 no.9
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    • pp.237-247
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    • 2019
  • The purpose of this study was to evaluate the level and intensity of emotional labor of physical therapists and occupational therapists, and to identify the factors affecting them. Cross-sectional study was conducted on physical therapists and occupational therapists across the country using self-populated questionnaire. A total of 2,000 questionnaires were distributed to retrieve 1,500 questionnaires(75%), of which 1,374 questionnaires(68.7%) were finally analyzed, excluding 126 that answered duplicates or were missing answers. Multi-linear regression was performed to identify factors on the strength of emotional labor. According to the analysis results, high-risk groups in the areas under 'Emotional demand and regulation' and 'Overload and conflict in customer service' and 'Emotional disharmony and hurt' were 29.4%, 19.0% and 22.0% respectively, especially in 'Emotional demand and regulation', 'Overload and conflict in customer service', 'Emotional disharmony and hurt' for women working days, and 49% of daily work hours. Accordingly, we will be able to regularly screen physical therapists and occupational therapists for dangerous groups, and manage the intensity of emotional labor through the creation of a therapist's working environment, such as limiting overtime hours and assigning appropriate number of patients. Through this study, the grounds and methods for mitigating the negative effects of emotional labor and mediating emotional labor should be provided.

The Effect of Factors on Aggression in Adolescents: Focusing on Individual, Parent, Friend Factors and SNS Usage (청소년의 공격성에 영향을 미치는 요인: 개인·부모·친구 요인과 소셜네트워크서비스(SNS) 이용 정도를 중심으로)

  • Lee, Yejin;Kim, Kyong-Beom;Heo, Min-Hee;Noh, Jin-Won;Im, Yu-Mi
    • The Journal of the Korea Contents Association
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    • v.21 no.4
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    • pp.699-706
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    • 2021
  • This study aims to identify the effects of factors on aggression in adolescents, focusing on the individual, parent, friend factors and SNS usage. In particular, this study is to provide a basis for easing aggression in adolescence by considering the emotional relationship of parents and friends. This study analyzed frequency, t-test, one-way batch distribution analysis(ANOVA), and multi-linear regression, using the data from the 7th year of the Korean Children and Youth Panel Survey. As a result, adolescents who frequently use SNS are more aggressive than adolescents who use less. Among the parental factors, the more abuse and excessive interference were found to be more aggressive, and the higher the coach, the lower the aggressiveness. Furthermore, among the friend factors, it has been shown that the higher the alienation, the more aggressive adolescents are. In order to reduce aggression among adolescents, it is necessary to prepare an integrated program considering the emotional relationship of parents and friends, who are the most influential neighbors, rather than simply restricting the use of SNS.

Association of osteoarthritis and bone mineral density in women -The health and nutritional examination survey in Kuri- (여성의 골관절염과 골밀도간의 관련성 분석 -구리시민 건강.영양진단 조사결과를 바탕으로-)

  • Sheen, Seung-Soo;Lee, Soon-Young;Min, Byung-Hyun;Suh, Il
    • Journal of Preventive Medicine and Public Health
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    • v.30 no.4 s.59
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    • pp.669-685
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    • 1997
  • Previous studies, reporting the inverse relationship between osteoarthritis and osteoporosis suggest the existence of possible pathophysiologic mechanisms between them. To examinine the hypothesis that 'bone mineral densities of women with osteoarthritis are significantly higher than that of women without osteoarthritis in Korea', subjects from the health and nutritional examination survey in Kuri city were sampled. Samples were selected through multi-stage sampling frame using established clusters in Kuri city. From August 18 to September 10,1997, the survey was conducted. Among the. total number of selected sample population (1,656 people), response .ate was 52.4 percent (348 men and 519 women). 420 women who took BMD measurement, radiologic exam, and anthropometric exam were selected for the analysis. The analytic results are as follows. 1. General characteristics: Mean BMD was $0.493g/cm^2$, mean age was 43.0, mean BMI was $23.9kg/m^2$. The number of women who experienced menopause was 106, hysterectomy was 19. There were 0 case of osteoarthritis of hip, 64 cases of osteoarthritis of knee, and 2 cases of osteoarthritis of hand. 2. Univariate analysis results: Mean BMD of women with the osteoarthritis of knee was significantly lower than that of women without the osteoarthritis of knee(0.4269 vs. $0.5057g/cm^2$). But, there were too few cases of osteoarthritis of hip and hand, so comparative studies of BMD in osteoarthritis of hip and hand could not be conducted. There were significant differences of BMD among pre-menopause group(0.5204), post-menopause group(0.4206), and hysterectomy group(0.4881). Additionally, there were significant differences of BMD among diabetes group(0.4297), impaired glucose tolerance group(0.4874), and normal group(0.5057). Furthermore, age, parity, BMI, bioimpedance were significantly related with BMD. 3. Multivariate analysis results: To examinine the relationship between osteoarthritis and BMD while controlling the other variables' effects which were significant in the univariate analyses, multiple linear regression analysis was done. But, it was found that osteoarthritis of knee was not a significant variable to BMD anymore. While age and menopause had significant negative relationship with BMD. Diabetes, parity, BMI, and bioimpedance did not have significant relationships with BMD. After stratification of subjects according to menopause, multiple linear regression analyses were done to each strata. Consequently, age in post-menopause group, age and osteoarthritis of knee in hysterectomy group showed significant negative relationship with BMD. The results did not support the many results of other previous studies done with white men and women. further studies of biological plausibility to Korean women are recommended. Also it is suggested that longitudinal study to verify the relationship between osteoarthritis and BMD will be valuable.

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Rice Yield Estimation Using Sentinel-2 Satellite Imagery, Rainfall and Soil Data (Sentinel-2 위성영상과 강우 및 토양자료를 활용한 벼 수량 추정)

  • KIM, Kyoung-Seop;CHOUNG, Yun-Jae;JUN, Byong-Woon
    • Journal of the Korean Association of Geographic Information Studies
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    • v.25 no.1
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    • pp.133-149
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    • 2022
  • Existing domestic studies on estimating rice yield were mainly implemented at the level of cities and counties in the entire nation using MODIS satellite images with low spatial resolution. Unlike previous studies, this study tried to estimate rice yield at the level of eup-myon-dong in Gimje-si, Jeollabuk-do using Sentinel-2 satellite images with medium spatial resolution, rainfall and soil data, and then to evaluate its accuracy. Five vegetation indices such as NDVI, LAI, EVI2, MCARI1 and MCARI2 derived from Sentinel-2 images of August 1, 2018 for Gimje-si, Jeollabuk-do, rainfall and paddy soil-type data were aggregated by the level of eup-myon-dong and then rice yield was estimated with gamma generalized linear model, an expanded variant of multi-variate regression analysis to solve the non-normality problem of dependent variable. In the rice yield model finally developed, EVI2, rainfall days in September, and saline soils ratio were used as significant independent variables. The coefficient of determination representing the model fit was 0.68 and the RMSE for showing the model accuracy was 62.29kg/10a. This model estimated the total rice production in Gimje-si in 2018 to be 96,914.6M/T, which was very close to 94,470.3M/T the actual amount specified in the Statistical Yearbook with an error of 0.46%. Also, the rice production per unit area of Gimje-si was amounted to 552kg/10a, which was almost consistent with 550kg/10a of the statistical data. This result is similar to that of the previous studies and it demonstrated that the rice yield can be estimated using Sentinel-2 satellite images at the level of cities and counties or smaller districts in Korea.

A Study of Tasseled Cap Transformation Coefficient for the Geostationary Ocean Color Imager (GOCI) (정지궤도 천리안위성 해양관측센서 GOCI의 Tasseled Cap 변환계수 산출연구)

  • Shin, Ji-Sun;Park, Wook;Won, Joong-Sun
    • Korean Journal of Remote Sensing
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    • v.30 no.2
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    • pp.275-292
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    • 2014
  • The objective of this study is to determine Tasseled Cap Transformation (TCT) coefficients for the Geostationary Ocean Color Imager (GOCI). TCT is traditional method of analyzing the characteristics of the land area from multi spectral sensor data. TCT coefficients for a new sensor must be estimated individually because of different sensor characteristics of each sensor. Although the primary objective of the GOCI is for ocean color study, one half of the scene covers land area with typical land observing channels in Visible-Near InfraRed (VNIR). The GOCI has a unique capability to acquire eight scenes per day. This advantage of high temporal resolution can be utilized for detecting daily variation of land surface. The GOCI TCT offers a great potential for application in near-real time analysis and interpretation of land cover characteristics. TCT generally represents information of "Brightness", "Greenness" and "Wetness". However, in the case of the GOCI is not able to provide "Wetness" due to lack of ShortWave InfraRed (SWIR) band. To maximize the utilization of high temporal resolution, "Wetness" should be provided. In order to obtain "Wetness", the linear regression method was used to align the GOCI Principal Component Analysis (PCA) space with the MODIS TCT space. The GOCI TCT coefficients obtained by this method have different values according to observation time due to the characteristics of geostationary earth orbit. To examine these differences, the correlation between the GOCI TCT and the MODIS TCT were compared. As a result, while the GOCI TCT coefficients of "Brightness" and "Greenness" were selected at 4h, the GOCI TCT coefficient of "Wetness" was selected at 2h. To assess the adequacy of the resulting GOCI TCT coefficients, the GOCI TCT data were compared to the MODIS TCT image and several land parameters. The land cover classification of the GOCI TCT image was expressed more precisely than the MODIS TCT image. The distribution of land cover classification of the GOCI TCT space showed meaningful results. Also, "Brightness", "Greenness", and "Wetness" of the GOCI TCT data showed a relatively high correlation with Albedo ($R^2$ = 0.75), Normalized Difference Vegetation Index (NDVI) ($R^2$ = 0.97), and Normalized Difference Moisture Index (NDMI) ($R^2$ = 0.77), respectively. These results indicate the suitability of the GOCI TCT coefficients.

Decomposition Characteristics of Fungicides(Benomyl) using a Design of Experiment(DOE) in an E-beam Process and Acute Toxicity Assessment (전자빔 공정에서 실험계획법을 이용한 살균제 Benomyl의 제거특성 및 독성평가)

  • Yu, Seung-Ho;Cho, Il-Hyoung;Chang, Soon-Woong;Lee, Si-Jin;Chun, Suk-Young;Kim, Han-Lae
    • Journal of Korean Society of Environmental Engineers
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    • v.30 no.9
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    • pp.955-960
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    • 2008
  • We investigated and estimated at the characteristics of decomposition and mineralization of benomyl using a design of experiment(DOE) based on the general factorial design in an E-beam process, and also the main factors(variables) with benomyl concentration(X$_1$) and E-beam irradiation(X$_2$) which consisted of 5 levels in each factor was set up to estimate the prediction model and the optimization conditions. At frist, the benomyl in all treatment combinations except 17 and 18 trials was almost degraded and the difference in the decomposition of benomyl in the 3 blocks was not significant(p > 0.05, one-way ANOVA). However, the % of benomyl mineralization was 46%(block 1), 36.7%(block 2) and 22%(block 3) and showed the significant difference of the % that between each block(p < 0.05). The linear regression equations of benomyl mineralization in each block were also estimated as followed; block 1(Y$_1$ = 0.024X$_1$ + 34.1(R$^2$ = 0.929)), block 2(Y$_2$ = 0.026X$_2$ + 23.1(R$^2$ = 0.976)) and block 3(Y$_3$ = 0.034X$_3$ + 6.2(R$^2$ = 0.98)). The normality of benomyl mineralization obtained from Anderson-Darling test in all treatment conditions was satisfied(p > 0.05). The results of prediction model and optimization point using the canonical analysis in order to obtain the optimal operation conditions were Y = 39.96 - 9.36X$_1$ + 0.03X$_2$ - 10.67X$_1{^2}$ - 0.001X$_2{^2}$ + 0.011X$_1$X$_2$(R$^2$ = 96.3%, Adjusted R$^2$ = 94.8%) and 57.3% at 0.55 mg/L and 950 Gy, respectively. A Microtox test using V. fischeri showed that the toxicity, expressed as the inhibition(%), was reduced almost completely after an E-beam irradiation, whereas the inhibition(%) for 0.5 mg/L, 1 mg/L and 1.5 mg/L was 10.25%, 20.14% and 26.2% in the initial reactions in the absence of an E-beam illumination.