• Title/Summary/Keyword: Mean-Variance Analysis

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$\frac{1}{4}$ß$\frac{1}{2}$ (주요 식량작물에 대한 시비적량 추정에 관한 연구)

  • 장석환;최재성
    • The Korean Journal of Applied Statistics
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    • v.1 no.2
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    • pp.34-44
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    • 1987
  • In order to estimate the optimum fertilizer level for rice, a major food crop, the experimental results obtained from the fertilizer trials conducted at 642 experimental sites(farmers' fields) throughout the country for the period from 1976 to 1979 were examined. Since non-significant interactions among fertilizers have been ovserved from the past experiences, only thirteen treatments(combinations of fertilizer levels) for the experiments as given in the Table 1 were chosen such that simple response curves can be fitted with independent variables being N, $P_2O_5, and K_2O$. Weighted combining analysis of variance was also carried out for each type of paddy fields to test the significance of Treatments $\times$ Experimental sites interaction, and highly significant variability in response to treatments among experimental sites in the same type of paddy fields was observed in most types of fields. For the types of paddy fields where the treatments $\times$ experimental sites interaction was not significant, separate response curves for N, $P_2O_5, and K_2O$ were estimated on the basis of the mean yields of rice, and common values of the optimum levels of fertilizers were extimated thereform. When the interaction is significant, response curves were fitted for each experimental sites. The average fertilizer doses estimated for the types of paddy fields based on the individual sites are given in Tables 7-1 and 7-2.

A Comparison of Density and Patient Doses According to kVp and mAs Changes in General Radiography (일반촬영에서 kVp와 mAs의 변화에 따른 농도와 환자 선량 비교)

  • Kang, Eun Bo
    • Journal of the Korean Society of Radiology
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    • v.13 no.7
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    • pp.987-994
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    • 2019
  • Low energy x-rays that occur in the low tube voltage radiography of general radiography are absorbed strongly in the body and do not aid image quality enhancement. This study maintains titer in general radiography while using tube current that are proportional to density and the tube voltage 15% principle according to density to reduce patient exposure doses, and area doses and entrance surface doses were measured to compare patient exposure doses. In hand, knee, abdomen, and skull radiography, kVp was increased to 115% and mAs was decreased to 50% and kVp was decreased to 85% while mAs was increased to 200% and area doses and entrance surface doses were measured to compare relative doses. Also, 5 places in each image were set, density was measured, and Kruskal wallis H test was conducted to observe significance probabilities between groups. To fix density, kVp was increased to 115% and mAs was decreased to 50% and after measurements of mean area doses and entrance surface doses were made by each part, each decreased to 58.68% and 59.85% when standard doses were set to 100%, and each increased to 147.28% and 159.9% when kVp was decreased to 85% and mAs was increased to 200%. Comparisons of density changes showed that hand, knee, abdomen, and skull radiography all displayed significance probabilities>0.05, showing no changes in concentration. Radiography that increases kVp and lowers mAs through reasonable calculations within ranges that don't affect resolution and contrast seems to be a simple way to decrease patient exposure doses.

Influencing Factors for Post-traumatic Growth in Patients with Breast Cancer (유방암 환자의 외상 후 성장 영향 요인)

  • Choi, Sung-Hee;Lee, Young-Whee
    • The Journal of the Korea Contents Association
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    • v.16 no.11
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    • pp.499-509
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    • 2016
  • This study was undertaken to investigate the factors that influence post-traumatic growth in patients with breast cancer. The study subjects were 100 outpatients with breast cancer who visited the outpatient clinic of a university hospital. The instruments used for this study were Korean Post-traumatic Inventory (K-PTGI), Modified Medical Outcomes Study Social Support Survey (mMOS-SS), Self-Efficacy Scale for Self-Management of Breast Cancer (SESSM-B) and Cancer Coping Questionnaire (CCQ). The data were analyzed by t-test, ANOVA, Pearson-correlation coefficient, and stepwise multiple regression using SPSS/WIN 21.0. The mean score of post-traumatic growth was $3.4{\pm}0.9$ out of 5. Post traumatic growth had statistically significant correlation with social support, breast cancer self-management self-efficacy, and coping behavior. In stepwise multiple regression analysis, post-traumatic growth was significantly influenced by therapeutic compliance related self-efficacy and positive reframing coping behavior and it was account for 29% of the total variance. These results suggest that these influencing factors should be considered in developing the nursing intervention to improve the post-traumatic growth in patient with breast cancer.

Safety-practice and Its Related Factors among Elementary students in a rural area (일부 초등학생의 안전실천 관련요인)

  • Lee, Young-Mee
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.5
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    • pp.1115-1125
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    • 2009
  • Purpose: The purpose of this study was to investigate the Safety-practice and Its Related Factors among Elementary students in rural area, to provide the basic data for prevention for safety accident occurrence in order to improve the QOL. Methods: The subjects of this study were 549 elementary students using self-report questionnaires. The collected data was analyzed using descriptive statistics, t-test, ANOVA, Scheffe's test, Pearson correlation coefficient and stepwise multiple regression with SPSS 12.0 Program. Results: The mean score for level of the safety awareness was 3.55(${\pm}.36$) and of the safety practice, 2.98(${\pm}.48$). The score of Safety-practice was statistically significant difference according to students' gender(p= .028) and students' grade(p= .004), the number of friends(p= .002), the level of school life adaptation(p= .000), recognized learning proficiency(p= .000), personality(p= .005), curiosity(p= .003), the level of demand for safety education(p= .000), the level of safety-education conducted by parents(p= .000), the level of safety-education conducted by teacher(p= .000). Stepwise multiple regression analysis for Safety-practice revealed that the most powerful predictor was level of Safety-awareness and self-esteem, the level of safety-education conducted by parents explained 28.8% of the variance. Conclusions: Therefore, it is necessary to develop safety practice promotion program in order to enhance the quality of life of elementary students. Future studies need to be pursued to find various variances.

The Influence of Communication, Resilience, Mental health on Military Adjustment of Soldiers in the Rear Air Force (후방 공군 병사의 의사소통, 회복탄력성, 정신건강이 군 적응에 미치는 영향)

  • AN, Hyo-Ja;Bae, Yeong-Ju;Cho, Myeong-Suk;Kim, Eun-Ha;Kim, Young-Ok;Lee, Young-Lye;Kim, Jeong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.7
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    • pp.694-703
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    • 2016
  • This study was designed to investigate the factors that influence soldiers' military adjustment in the rear air force. The data were collected through a survey of 160 soldiers in N city from Nov. 16th to Dec. 11th, 2015, using appropriate instruments to assess their military adjustment, type of communication, resilience and mental health, and analyzed using IBM SPSS WIN 21. The mean scores for military adjustment, resilience, mental well-being and disorder were $1.25{\pm}0.33$, $3.69{\pm}0.56$, $2.98{\pm}0.94$ and $1.24{\pm}0.36$, respectively. In the analysis of their general characteristics, there were significant differences in age, perceived health and future career. Significantly positive correlations were found between adjustment and placating, blaming and irrelevant communication and mental disorder and significantly negative correlations were found between adjustment and resilience and mental well-being. Mental disorder and blaming communication accounted for 41% of the variance in the military adjustment. The result of this study shows that soldiers' military adjustment is related to mental disorder and blaming communication.

A Study on the Relation between the Number of First Aid Training and the Performance of Facilities Security Personnel (시설보안요원의 응급처치교육이수와 직무수행 관계에 관한 연구)

  • Kim, Sin-Hye;Han, I-Jun
    • Korean Security Journal
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    • no.59
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    • pp.91-108
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    • 2019
  • The purpose of this study is to investigate the relationship between the number of first aid training and safety performance. The researcher's questionnaire consisted of three variables: necessity of first aid education, application to security practice, and improvement of job satisfaction. In this study, Chronbach's Alpha coefficients were calculated to measure the internal validity for the reliability of the questionnaire. In order to verify the validity of the measured variables, exploratory factor analysis was carried out using the Berimax rotation method. The mean variance extracted AVE and the conceptual reliability CR value of the measurement result variables were both above the allowable reference value of 0.5 and it was judged to be a good test in terms of intensive validity. As a result of the hypothesis test, the standardization coefficient was 1.106 for 'necessity of first aid education ⇒ applied to security practice work', and 'applied to security work practice ⇒ improvement of job satisfaction' was 1.063 and the relationship of hypothesis 1 hypothesis 2 was significant (+), Respectively. Therefore, in order to increase the job satisfaction of security related workers, it is necessary to support first aid education and to receive first aid education.

Estimating Benzene Exposure Level over Time and by Industry Type through a Review of Literature on Korea

  • Park, Donguk;Choi, Sangjun;Ha, Kwonchul;Jung, Hyejung;Yoon, Chungsik;Koh, Dong-Hee;Ryu, Seunghun;Kim, Soogeun;Kang, Dongmug;Yoo, Kyemook
    • Safety and Health at Work
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    • v.6 no.3
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    • pp.174-183
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    • 2015
  • The major purpose of this study is to construct a retrospective exposure assessment for benzene through a review of literature on Korea. Airborne benzene measurements reported in 34 articles were reviewed. A total of 15,729 individual measurements were compiled. Weighted arithmetic means [AM(w)] and their variance calculated across studies were summarized according to 5-year period intervals (prior to the 1970s through the 2010s) and industry type. Industries were classified according to Korea Standard Industrial Classification (KSIC) using information provided in the literature. We estimated quantitative retrospective exposure to benzene for each cell in the matrix through a combination of time and KSIC. Analysis of the AM(w) indicated reductions in exposure levels over time, regardless of industry, with mean levels prior to the 1980-1984 period of 50.4 ppm (n = 2,289), which dropped to 2.8 ppm (n = 305) in the 1990-1994 period, and to 0.1 ppm (n = 294) in the 1995-1999 period. There has been no improvement since the 2000s, when the AM(w) of 4.3 ppm (n = 6,211) for the 2005-2009 period and 4.5 ppm (n = 3,358) for the 2010-2013 period were estimated. A comparison by industry found no consistent patterns in the measurement results. Our estimated benzene measurements can be used to determine not only the possibility of retrospective exposure to benzene, but also to estimate the level of quantitative or semiquantitative retrospective exposure to benzene.

Development of Line Density Index for the Quantification of Oceanic Thermal Fronts (해양의 수온전선 정량화를 위한 선밀도 지수 개발)

  • Cho, Hyun-Woo;Kim, Kye-Hyun
    • Journal of the Korean Association of Geographic Information Studies
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    • v.9 no.2
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    • pp.227-238
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    • 2006
  • Line density index(LDI) was developed to quantify a densely isothermal line rate as standard index in the ocean environment. Theoretical background on the LDI development process restricting index range 0 to 100 was described. And validation test was done for the LDI application condition that total line length is not greater than 1/10 of unit area. NOAA SST(Sea Surface Temperature) data were used for the experimental application of LDI in the South Sea of Korea. Using GIS, $0.1^{\circ}C$ isothermal lines were linearized as vector data form SST raster data, and unit area were built as polygon data. For the LDI calculation, spatial overlapping(line in polygon) was implemented. To analyze the effect of unit area size for the LDI distribution, two cases of unit area size were designed and descriptive statistics was calculated including performing normality test. The results showed no change of LDI's essential characteristics such as mean and normality except for the range of value, variance and standard deviation. Accordingly, it was found that complex structure of thermal front and even smaller scale of front width than unit area size could influence on the LDI distribution. Also, correlation analysis performed between LDI and difference of temperature(${\Delta}T^{\circ}C$), and horizontal thermal gradient(${\Delta}T^{\circ}C/km$) on the front was obtained from linear regression model. This obtained value was compared with the results from previous researches. Newly developed LDI can be used to compare the thermal front regions changing spatio-temporally in the ocean environment using absolute index value. It is considered to be significant to analyze the relationship between thermal front and marine environment or front and marine organisms in a quantitative approach described in this study.

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The Contribution of Maternal-Fetal Attachment: Taegyo, Maternal Fatigue and Social Support during Pregnancy (태아애착에의 영향요인: 임부의 피로, 사회적지지, 태교실천)

  • Yu, Mi;Kim, Miok
    • Child Health Nursing Research
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    • v.20 no.4
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    • pp.247-254
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    • 2014
  • Purpose: Maternal-fetal attachment in a pregnant woman is important for her health and for her child's emotional stability. This study was done to identify the contribution of maternal fatigue, social support, and Taegyo to maternal-fetal attachment based on a survey of pregnant women. Methods: The study was a descriptive correlation study. Participants were 211 from two women's health clinic centers. Data were analyzed using t-test, ANOVA, Pearson correlation coefficients and stepwise multiple regression. Results: Mean scores for maternal-fetal attachment, Taegyo, maternal fatigue, and social support were 93.74 (range 25-125), 64.76 (17-85), 24.12 (10-40), and 54.43 (22-132), respectively. There were significant differences in maternal-fetal attachment according to parity, breast feeding experience, and putting prenatal education into practice. Multiple regression analysis showed that the key determinants of maternal-fetal attachment, were Taegyo (${\beta}$=.67), maternal fatigue (${\beta}$=.21), and social support (${\beta}$=.13), and these explained 55% of the total variance of attachment. Conclusion: The results suggest a need to encourage Taegyo in prenatal management program and provide methods for fatigue resolution and promotion of social support.

Comparison of Relative Thickness of the Iliotibial Band Following Four Self-Stretching Exercises

  • Kim, Hyun-Sook;Yoon, Tae-Lim
    • Physical Therapy Korea
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    • v.19 no.4
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    • pp.24-31
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    • 2012
  • The aim of this study was to investigate the effectiveness of self-stretching exercises for iliotibial band (ITB) (Side-lying; right hip and knee were flexed to support the pelvis while left hip was extended and adducted, Standing A; side-bending of the trunk on standing with crossed leg, Standing B; same as Standing A, except the hands were clasped overhead and shifted right side, and Standing C; same as Standing B, except moving the arms diagonally downward) to help determine the most effective self-stretching method to stretch ITB. Twenty-one healthy subjects who do not have ITB shortness from Yonsei University (14 men and 7 women) between the ages of 18 to 28 years voluntarily participated. Ultrasound was performed to measure the thickness of the ITB between the long axis of the ITB and the level parallel to the lateral femoral epicondyle during four self-stretching exercises. All data were found to approximate a normal distribution. We used a one-way repeated-measures analysis of variance (ANOVA) to compare the thickness of the ITB among all self-stretching exercises. The level of significance was set at ${\alpha}$=.05. The ANOVA was followed by Bonferroni's correction. The overall mean of ITB thickness was $1.14{\pm}.4$ mm (${\pm}$ standard deviation) in resting status. The change in the ITB thickness in percentages between the tested position of each self-stretching exercises and resting status was significant (p<.05) (Side-lying $26.62{\pm}10.18%$ with 95% confidence interval [CI]=21.99~31.25%; Standing A $29.46{\pm}16.19%$ with 95% CI=22.09~36.84%; Standing B $44.06{\pm}14.82%$ with 95% CI=37.31~50.81%; Standing C $53.76{\pm}12.1%$ with 95% CI=48.25~59.29%). Results indicated significant differences among four self-stretching exercises except Side-lying versus Standing A (p<.01). Based on these findings, the Standing C self-stretching exercise was the most effective in stretching the ITB thickness among four types of ITB self-stretching exercises. Additionally, the Side-lying self-stretching exercise using gravity to stretch the ITB is recommended as a low-load (low-intensity), long-duration stretch.