• Title/Summary/Keyword: mean-variance model

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A Study on the Sociopsychological Factors Influencing the Dietary Compliance of Diabetics Using Questionnaire (당뇨환자의 식사처방 순응도에 영향을 미치는 사회심리적 요인 분석 II: 설문조사 방법을 이용하여)

  • 박동연;최선정;박혜련;안홍석
    • Korean Journal of Community Nutrition
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    • v.5 no.1
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    • pp.36-49
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    • 2000
  • The purpose of the study was to find the sociopsychological factors predicting the intention of compliance with the dietary regimen in diabetes with a questionnaire. Data were collected from 282 adult noninsulin-dependent diabetics in Seoul, Kyoggida, and Kyongsangbukdo in Korea. Stepwise multiple regression analysis was conducted with predictor variables from theories of the Health Belief Model, Social Cognitive Model, The Theory of Reasoned Action , and Social Support. The behavioral intention of compliance with the prescribed diet was the independent variable. Subjects norm self-efficacy knowledge about diet therapy, outcome expectation, relationship with medical team, threat of deterioration of disease, and social support were the independent variables, The mean score of behavior intention was high ie 35.3 out to 42. Subjective norm and self-efficacy were the significant variables to predict the intention of dietary compliance. These variables comprised 39% of the common variance. To increase dietary compliance by influence of the referents and improve self-efficacy significant referents must be included and concrete and practical methods to follow the dietary regimen must be provided in nutrition education.

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A Study on the Stochastic Modeling for Stream Flow Generation (하천유량의 모의발생을 위한 추계학적 모형의 적용에 관한 연구)

  • Lee, Joo-Heon
    • Journal of the Korean Society of Hazard Mitigation
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    • v.1 no.2 s.2
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    • pp.115-121
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    • 2001
  • The purpose of the synthetic generation of monthly river flows based on the short term observed data by means of stochastic models is to provide abundant input data to the water resources systems of which the system performance and operation policy are to be determined beforehand. In this study, a multivariate autoregressive model has been applied to generate monthly flows of the multi sites considering the correlations between each site. The model performance was examined using statistical comparisons between the historical and generated monthly series such as mean, variance, skewness and correlation coefficients. The results of this study showed that the modeled generated flows were statistically similar to the historical flows.

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Development of Synthetic Unit Hydrograph for Estimation of Runoff in Ungauged Watershed (미계측 유역의 유출량 산정을 위한 합성단위도 개발)

  • Choi, Yong Joon;Kim, Joo Cheol;Jeong, Dong Kug
    • Journal of Korean Society on Water Environment
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    • v.26 no.3
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    • pp.532-539
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    • 2010
  • The synthetic unit hydrograph is developed and verified using Nash model and characteristic velocities considering geomorphological dispersion in this present study. Application watersheds are selected 5 subwatersheds of Bocheong basin. The mean and variance of hillslope and stream path length are estimated in each watershed with GIS. Characteristic velocities are calculated using estimated path lengths and moment characteristics of rainfall-runoff data. Characteristic velocities of random devised 7 ungauged watersheds are estimated through regional analysis of chracteristic velocities in guaged watershed. And Nash model parameters and IUH are derived using characteristic velocities and path length in the gauged and ungauged watershed. The result to compare of IUH about gauged watershed and random devised ungauged watershed in application watershed presents coherently hydrologic response characteristics that peak discharge is reduced and peak time is extended. In conclusion, Developed synthetic unit hydrograph in this study expects that it is useful method to estimate runoff discharge for managing of water pollution in ungauged watershed.

Tolerance Optimization of Design Variables in Lower Arm by Using Response Surface Model and Process Capability Index (반응표면모델과 공정능력지수를 적용한 로워암 설계변수의 공차최적화)

  • Lee, Kwang Ki;Ro, Yun Cheol;Han, Seung Ho
    • Korean Journal of Computational Design and Engineering
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    • v.18 no.5
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    • pp.359-366
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    • 2013
  • In the lower arm design process, a tolerance optimization of the variance of design variables should be preceded before manufacturing process, since it is very cost-effective compared to a strict management of tolerance of products. In this study, a design of experiment (DOE) based on response surface model (RSM) was carried out to find optimized design variables of the lower arm, which can meet a given requirement of probability constraint for the process capability index (Cpk) of the weight and maximum stress. Then, the design space was explored by using the central composite design method, in which the 2nd order Taylor expansion was applied to predict a standard deviation of the responses. The optimal solutions satisfying the probability constraint of the Cpk were found by considering both of the mean value and the standard deviation of the design variables.

Predictors of Behavioral and Psychological Symptoms of Dementia: Based on the Model of Multi-Dimensional Behavior (다차원적 행동 모델에 근거한 치매 노인의 정신행동 증상 예측요인)

  • Yang, Jeong Eun;Hong, Gwi-Ryung Son
    • Journal of Korean Academy of Nursing
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    • v.48 no.2
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    • pp.143-153
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    • 2018
  • Purpose: The purpose of this study was to identify factors predicting behavioral and psychological symptoms of dementia (BPSD) in persons with dementia. Factors including the patient, caregiver, and environment based on the multi-dimensional behavioral model were tested. Methods: The subjects of the study were 139 pairs of persons with dementia and their caregivers selected from four geriatric long-term care facilities located in S city, G province, Korea. Data analysis included descriptive statistics, inverse normal transformations, Pearson correlation coefficients, Spearman's correlation coefficients and hierarchical multiple regression with the SPSS Statistics 22.0 for Windows program. Results: Mean score for BPSD was 40.16. Depression (${\beta}=.42$, p<.001), exposure to noise in the evening noise (${\beta}=-.20$, p=.014), and gender (${\beta}=.17$, p=.042) were factors predicting BPSD in long-term care facilities, which explained 25.2% of the variance in the model. Conclusion: To decrease BPSD in persons with dementia, integrated nursing interventions should consider factors of the patient, caregiver, and environment.

Appropriate identification of optimum number of hidden states for identification of extreme rainfall using Hidden Markov Model: Case study in Colombo, Sri Lanka

  • Chandrasekara, S.S.K.;Kwon, Hyun-Han
    • Proceedings of the Korea Water Resources Association Conference
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    • 2019.05a
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    • pp.390-390
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    • 2019
  • Application of Hidden Markov Model (HMM) to the hydrological time series would be an innovative way to identify extreme rainfall events in a series. Even though the optimum number of hidden states can be identify based on maximizing the log-likelihood or minimizing Bayesian information criterion. However, occasionally value for the log-likelihood keep increasing with the state which gives false identification of the optimum hidden state. Therefore, this study attempts to identify optimum number of hidden states for Colombo station, Sri Lanka as fundamental approach to identify frequency and percentage of extreme rainfall events for the station. Colombo station consisted of daily rainfall values between 1961 and 2015. The representative station is located at the wet zone of Sri Lanka where the major rainfall season falls on May to September. Therefore, HMM was ran for the season of May to September between 1961 and 2015. Results showed more or less similar log-likelihood which could be identified as maximum for states between 4 to 7. Therefore, measure of central tendency (i.e. mean, median, mode, standard deviation, variance and auto-correlation) for observed and simulated daily rainfall series was carried to each state to identify optimum state which could give statistically compatible results. Further, the method was applied for the second major rainfall season (i.e. October to February) for the same station as a comparison.

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A Structural Equation Model for Quality of Life of Super-Aged Women

  • Jung-Hyun Choi
    • Journal of Practical Engineering Education
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    • v.14 no.3
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    • pp.609-615
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    • 2022
  • This study aims to investigate the relationship between quality of life, activities of daily living, and depression among Korean super-aged women. In this study, the 7th (2018) data of the Korean Longitudinal Study of Aging (KLoSA) were used. The participants in this study were 363 super-aged women. The mean age was 88.67 years old. Quality of life was significantly related with Activities of daily living (ADL) (r = .34, p < .001), and depression (r = -.47, p < .001). The analysis of the hypothesized model showed a good fit to the data except for the χ2 value (χ2 = 38.8, df = 11, p < .001, CFI = .98, TLI = .96, RMSEA = 0.08). The hypothesized model explained 34% of the variance in super-aged women. The activities of daily living of elderly women had an indirect effect on quality of life via depression. Very old women with a high level of ADL were more likely to be feeling less depression, and elderly people who had less depression were likely to have a better quality of life. The findings thus highlight prevailing depression and activities of daily living as critical foci for clinical management strategies in super-aged women.

Contribution of local site-effect on the seismic response of suspension bridges to spatially varying ground motions

  • Adanur, Suleyman;Altunisik, Ahmet C.;Soyluk, Kurtulus;Dumanoglu, A. Aydin;Bayraktar, Alemdar
    • Earthquakes and Structures
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    • v.10 no.5
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    • pp.1233-1251
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    • 2016
  • In this paper, it is aimed to determine the stochastic response of a suspension bridge subjected to spatially varying ground motions considering the geometric nonlinearity. Bosphorus Suspension Bridge built in Turkey and connects Europe to Asia in Istanbul is selected as a numerical example. The spatial variability of the ground motion is considered with the incoherence, wave-passage and site-response effects. The importance of site-response effect which arises from the difference in the local soil conditions at different support points of the structure is also investigated. At the end of the study, mean of the maximum and variance response values obtained from the spatially varying ground motions are compared with those of the specialised cases of the ground motion model. It is seen that each component of the spatially varying ground motion model has important effects on the dynamic behaviour of the bridge. The response values obtained from the general excitation case, which also includes the site-response effect causes larger response values than those of the homogeneous soil condition cases. The variance values calculated for the general excitation case are dominated by dynamic component at the deck and Asian side tower. The response values obtained for the site-response effect alone are larger than the response values obtained for the incoherence and wave-passage effects, separately. It can be concluded that suspension bridges are sensitive to the spatial variability of ground motion. Therefore, the incoherence, the wave-passage and especially the site-response effects should be considered in the stochastic analysis of this type of engineering structures.

Estimation of genetic relationships between growth curve parameters in Guilan sheep

  • Hossein-Zadeh, Navid Ghavi
    • Journal of Animal Science and Technology
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    • v.57 no.5
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    • pp.19.1-19.6
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    • 2015
  • The objective of this study was to estimate variance components and genetic parameters for growth curve parameters in Guilan sheep. Studied traits were parameters of Brody growth model which included A (asymptotic mature weight), B (initial animal weight) and K (maturation rate). The data set and pedigree information used in this study were obtained from the Agricultural Organization of Guilan province (Rasht, Iran) and comprised 8647 growth curve records of lambs from birth to 240 days of age during 1994 to 2014. Marginal posterior distributions of parameters and variance components were estimated using TM program. The Gibbs sampler was run 300000 rounds and the first 60000 rounds were discarded as a burn-in period. Posterior mean estimates of direct heritabilities for A, B and K were 0.39, 0.23 and 0.039, respectively. Estimates of direct genetic correlation between growth curve parameters were 0.57, 0.03 and -0.01 between A-B, A-K and B-K, respectively. Estimates of direct genetic trends for A, B and K were positive and their corresponding values were $0.014{\pm}0.003$ (P < 0.001), $0.0012{\pm}0.0009$ (P > 0.05) and $0.000002{\pm}0.0001$ (P > 0.05), respectively. Residual correlations between growth curve parameters varied form -0.52 (between A-K) to 0.48 (between A-B). Also, phenotypic correlations between growth curve parameters varied form -0.49 (between A-K) to 0.47 (between A-B). The results of this study indicated that improvement of growth curve parameters of Guilan sheep seems feasible in selection programs. It is worthwhile to develop a selection strategy to obtain an appropriate shape of growth curve through changing genetically the parameters of growth model.

The influence of eHealth literacy, reproductive health knowledge, and self-esteem on health-promoting behaviors in early adult women: a cross-sectional survey (성인초기 여성의 e헬스 문해력, 생식건강지식, 자아존중감이 건강증진행위에 미치는 영향: 설문조사연구)

  • Hye Sook Shin;Young A Song
    • Women's Health Nursing
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    • v.28 no.4
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    • pp.329-337
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    • 2022
  • Purpose: The purpose of this study was to investigate the influence of eHealth literacy, reproductive health knowledge, and self-esteem on early adult women's health-promoting behaviors (HPB). This study was based on Pender's health promotion model as a theoretical underpinning. Methods: Early adult women aged 18 to 35 years (n=165) were recruited by posting advertisements on social network sites for a student club and a faith-based community in Ansan, Korea. Willing individuals were invited to participate in the online survey from June 1 to June 30, 2022. Standardized instruments were used to measure HPB, eHealth literacy, reproductive health knowledge, and self-esteem. General characteristics included income level, perceived subjective health, and internet usage time. The collected data were analyzed using the independent t-test, one-way analysis of variance, Pearson correlation coefficients, and multiple regression. Results: The mean age of the respondents was 21.97±3.87 years. The total HPB score was 120.69, corresponding to a moderate level; and the total scores for eHealth literacy (30.24), knowledge of reproductive health (23.04), and self-esteem (35.62) were higher than the midpoint. The model explained 53.3% of variance in HPB, and self-esteem (β=.48, p<.001) was the most influential factor. Other influential factors were, in descending order, higher economic level, higher subjective health status, greater eHealth literacy, and less internet use time (<2 hours/day). Conclusion: In order to promote the health of early adult women, counseling or programs that positively improve self-esteem appear promising, and eHealth literacy should be considered as a way to promote HPB using information technology.