• Title/Summary/Keyword: mean-variance model

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Subjective Health and Factors of Health-related Quality of Life in Elderly Haenyo (해녀 노인의 건강수준과 건강 관련 삶의 질에 영향을 미치는 요인연구)

  • Chae, Myungah;Kim, Jeung-Im;Choi, Kyung Sook;Han, Ki-Hye
    • Women's Health Nursing
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    • v.24 no.2
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    • pp.105-115
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    • 2018
  • Purpose: To investigate the subjective health and health-related quality of life (HRQoL) in Haenyo. Methods: Subjects were 100 elderly Haenyo in Jeju island who belonged to a fishing-village society. Main variables were activities of daily living (ADL), instrumental ADL (IADL), the HRQoL, subjective health, and depression. Subjective health and differences of HRQoL by variables were analyzed by t-test or ANOVA using IBM SPSS Statistics 23. Hierarchical multiple regression was executed to examine the effects of the major factors on the quality of life. Results: The mean age was 69.9 years, the mean period for diving career was 51.5 years, and work hours per month were 37.8. Comorbidity of diseases was 2.74, and the common health problems were osteoporosis and headache/dizziness. HRQoL was significantly different by age (F=4.52, p=.013), education (F=6.10, p=.003), muljil work years (F=3.93, p=.050), depression (t=-3.04, p=.030), subjective health state (F=30.62, p<.01), and degenerative arthritis (F=-2.38, p=.019). In the final model by hierarchical multiple regression, ADL/IADL (${\beta}=.41$, p<.001), depression (${\beta}=-.29$, p<.001), and subjective health (${\beta}=.43{\sim}.51$, p<.001) were significant and explained 63.5% of the total variance of HRQoL. Conclusion: Haenyo have specific health problems different from those of elderly women in general. ADL/IADL, depression and subjective health affected their HRQoL. It is clear that Haenyos' health problems need further study to improve their health.

A Study on the Determination of Grain Size of Heat-treated Stainless Steel Using Digital Ultrasonic Signal Processing Techniques. (디지털 초음파 신호처리 기법을 이용한 열처리된 스테인레스 스틸의 그레인 크기 결정에 관한 연구)

  • 임내묵;이영석;김성환
    • The Journal of the Acoustical Society of Korea
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    • v.18 no.8
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    • pp.84-93
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    • 1999
  • Determination of grain size of heat-treated stainless steel based fm digital ultrasonic signal processing technique is presented. This techniques consist in evidence accumulation with multiple feature parameters, difference absolute mean value(DAMV), variance(VAR), mean frequency (MEANF), auto regressive model coefficient(ARC) and linear cepstrum coefficient(LCC). Feature parameters were extracted from ultrasonic echo signal of heat-treated metals. It was found that a few parameters might not be sufficient to exactly evaluate the grain size of heat-treated metals. The determination of grain size of heat-treated metals was carried out through the evidence accumulation procedure using the distances measured with reference parameters. A fuzzy mapping function is designed to transform the distances for the application of the evidence accumulation method. In the work presented, heat-treated stainless steel samples with various grain sizes are examined. The processed experimental results supports the feasibility of the grain size determination technique presented.

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Financial Distress and its Predicting Factors among Iranian Cancer Patients

  • Fathollahzade, Abazar;Rahmani, Azad;Dadashzadeh, Abbas;Gahramanian, Akram;Esfahani, Ali;Javanganji, Leila;Nabiolahi, Leila
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.4
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    • pp.1621-1625
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    • 2015
  • Background: Financial distress due to the cost of cancer treatments is prevalent among cancer patients. Identifying the level of financial distress and its affecting factors has an important role in providing supportive services. Accordingly, the aims of this study were to determine these parameters among Iranian cancer patients. Materials and Methods: This descriptive-correlational study was undertaken among 262 cancer patients admitted to both private and public hospitals in East Azerbaijan province, Iran. The financial distress/financial well being scale was used to determine financial distress. The data were analyzed using SPSS software using descriptive and inferential statistics (multiple linear regression). Results: Among the 262 cancer patients, 57.3% were male and their mean age was 47.0 years. The mean score for financial distress was 4.12 (2.01). The final regression model demonstrated that the independent variables (predictors) of income less than living expenses, income equal to living expenses, having an employed spouse in governmental job and living with parents, with regression coefficients of -1.029, -0.515, 0.198, and 0.096, respectively, were predictors of financial distress among cancer patients. These variables accounted for 50% of changes in variance of financial distress. Conclusions: Iranian cancer patients have moderate to high levels of financial distress. Considering policies for managing direct and indirect costs of cancer treatments must be followed.

Validity and Reliability of Korean Version of the Revised Stress Appraisal Measure (RSAM) (한국어판 수정된 스트레스 평가 도구(Revised Stress Appraisal Measure)의 타당도와 신뢰도)

  • Kim, Jeong Sun;Kim, Kye-Ha;Kang, Hyuncheol
    • The Journal of the Korea Contents Association
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    • v.15 no.3
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    • pp.290-302
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    • 2015
  • The study purpose was to test the validity and reliability of the Korean version of the Revised Stress Appraisal Measure (RSAM) to assess stress appraisal in undergraduate students. Internal consistency reliability, construct and criterion validity were calculated using IBM SPSS Statistics 21 and AMOS 21 program. Survey data were collected from a convenience sample of 296 undergraduate students enrolled in five universities in G city and C area, South Korea. The Korean version of RSAM categorized into 5 factors explaining 68.4% of the total variance. The model of five subscales was validated by confirmatory factor analysis (p<.001, Goodness of Fit Index, Adjusted Goodness of Fit Index, Normed Fit Index, Comparative Fit Index >.08, Root Mean Square Error of Approximation=.056). In criterion validity, the scores for the scale were significantly correlated with the Perceived Stress Scale-Korean. Cronbach's alpha coefficient for the 19 items was .73~.89. The Korean RSAM showed satisfactory construct and criterion validity and reliability. Thus it may be an appropriate instrument for measuring stress appraisal in Korean university students.

Molecular analysis of genetic diversity, population structure, and phylogeny of wild and cultivated tulips (Tulipa L.) by genic microsatellites

  • Pourkhaloee, Ali;Khosh-Khui, Morteza;Arens, Paul;Salehi, Hassan;Razi, Hooman;Niazi, Ali;Afsharifar, Alireza;Tuyl, Jaap van
    • Horticulture, Environment, and Biotechnology : HEB
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    • v.59 no.6
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    • pp.875-888
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    • 2018
  • Tulip (Tulipa L.) is one of the most important ornamental geophytes in the world. Analysis of molecular variability of tulips is of great importance in conservation and parental lines selection in breeding programs. Of the 70 genic microsatellites, 15 highly polymorphic and reproducible markers were used to assess the genetic diversity, structure, and relationships among 280 individuals of 36 wild and cultivated tulip accessions from two countries: Iran and the Netherlands. The mean values of gene diversity and polymorphism information content were 0.69 and 0.66, respectively, which indicated the high discriminatory power of markers. The calculated genetic diversity parameters were found to be the highest in wild T. systola Stapf (Derak region). Bayesian model-based STRU CTU RE analysis detected five gene pools for 36 germplasms which corresponded with morphological observations and traditional classifications. Based on analysis of molecular variance, to conserve wild genetic resources in some geographical locations, sampling should be performed from distant locations to achieve high diversity. The unweighted pair group method with arithmetic mean dendrogram and principal component analysis plot indicated that among wild tulips, T. systola and T. micheliana Hoog exhibited the closest relationships with cultivated tulips. Thus, it can be assumed that wild tulips from Iran and perhaps other Middle East countries played a role in the origin of T. gesneriana, which is likely a tulip species hybrid of unclear origin. In conclusion, due to the high genetic variability of wild tulips, they can be used in tulip breeding programs as a source of useful alleles related to resistance against stresses.

Development of Nursing Clinical Judgment Scale (간호사의 임상판단 측정도구 개발)

  • Kwon, Shi Nae;Park, Hyojung
    • Journal of Korean Academy of Nursing
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    • v.53 no.6
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    • pp.652-665
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    • 2023
  • Purpose: This study aimed to develop a nursing clinical judgment scale (NCJS) and verify its validity and reliability in assessing the clinical judgment of nurses. Methods: A preliminary instrument of the NCJS comprising 38 items was first developed from attributes and indicators derived from a literature review and an in-depth/focus interview with 12 clinical nurses. The preliminary tool was finalized after 7 experts conducted a content validity test based on a data from a preliminary survey of 30 hospital nurses in Korea. Data were collected from 443 ward, intensive care unit, emergency room nurses who voluntarily participated in the survey through offline and online for the verification of the construct validity and reliability of the scale. Results: The final scale comprised 23 items scored on a 5-point Likert scale. Six factors - integrated data analysis, evaluation and reflection on interventions, evidence on interventions, collaboration among health professionals, patient-centered nursing, and collaboration among nurse colleagues - accounted for 64.9% of the total variance. Confirmatory factor analysis supported the fit of the measurement model, comprising six factors (root mean square error of approximation = .07, standardized root mean square residual = .04, comparative fit index = .90). Cronbach's α for all the items was .92. Conclusion: The NCJS is a valid and reliable tool that fully reflects the characteristics of clinical practice, and it can be used effectively to evaluate the clinical judgment of Korean nurses. Future research should reflect the variables influencing clinical judgment and develop an action plan to improve it.

Measurement of Shunt Amount Using Radionuclide Angiocardiography: Accuracy According to Level of Shunt and Associated Lesion (방사성 동위원소 심혈관 조영술을 이용한 단락량 측정법: 정확성에 영향을 미치는 인자)

  • Kim, Yang-Min
    • Nuclear Medicine and Molecular Imaging
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    • v.40 no.4
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    • pp.200-204
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    • 2006
  • Purpose: Determination of pulmonary to systemic blood flow ratio (QP/QS) is important for the management of patients with left-to-right shunt. This study was performed to assess the agreement of Qp/Qs ratio using the radionuclide method and oxymetry, to investigate the factors influencing the agreement, and to know how interchangeable the results of each technique. Materials and Methods: We compared the Qp/Qs measured by single-pass radionuclide angiocardiography and oxymetry during catheterization in 207 patients who underwent both studies. In radionuclide method, Qp/Qs was calculated from the pulmonary time-activity curves using a gamma variate fit. The correlation and Bland-Altman analysis were performed according to the levels of shunt and associated lesions. Results: The mean Qp/Qs was $1.83{\pm}0.50$ by radionuclide, and $1.74{\pm}0.51$ by oxymetry. The overall correlation coefficient was 0.86(p<0.001), and Bland-Altman range of agreement encompassing 4SD was 1.05. For atrial septal defect, ventricular septal defect, patent ductus arteriosus, tricuspid and mitral insufficiency, the correlation coefficient was 0.78, 0.90, 0.84, 0.63 and 0.44, and Bland-Altman range was 1.51, 0.74, 0.96, 1.57, and 1.50, respectively. Conclusion: There is good agreement but wide variance between the Qp/Qs ratios by radionuclide method and oxymetry. Associated atrioventricular valvar insufficiency decreases the correlation coefficient and widens the variance. Wide overall variance suggests that Qp/Qs measurements by two techniques should not be used interchangeably.

Development of Statistical Downscaling Model Using Nonstationary Markov Chain (비정상성 Markov Chain Model을 이용한 통계학적 Downscaling 기법 개발)

  • Kwon, Hyun-Han;Kim, Byung-Sik
    • Journal of Korea Water Resources Association
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    • v.42 no.3
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    • pp.213-225
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    • 2009
  • A stationary Markov chain model is a stochastic process with the Markov property. Having the Markov property means that, given the present state, future states are independent of the past states. The Markov chain model has been widely used for water resources design as a main tool. A main assumption of the stationary Markov model is that statistical properties remain the same for all times. Hence, the stationary Markov chain model basically can not consider the changes of mean or variance. In this regard, a primary objective of this study is to develop a model which is able to make use of exogenous variables. The regression based link functions are employed to dynamically update model parameters given the exogenous variables, and the model parameters are estimated by canonical correlation analysis. The proposed model is applied to daily rainfall series at Seoul station having 46 years data from 1961 to 2006. The model shows a capability to reproduce daily and seasonal characteristics simultaneously. Therefore, the proposed model can be used as a short or mid-term prediction tool if elaborate GCM forecasts are used as a predictor. Also, the nonstationary Markov chain model can be applied to climate change studies if GCM based climate change scenarios are provided as inputs.

Development of Stochastic Downscaling Method for Rainfall Data Using GCM (GCM Ensemble을 활용한 추계학적 강우자료 상세화 기법 개발)

  • Kim, Tae-Jeong;Kwon, Hyun-Han;Lee, Dong-Ryul;Yoon, Sun-Kwon
    • Journal of Korea Water Resources Association
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    • v.47 no.9
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    • pp.825-838
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    • 2014
  • The stationary Markov chain model has been widely used as a daily rainfall simulation model. A main assumption of the stationary Markov model is that statistical characteristics do not change over time and do not have any trends. In other words, the stationary Markov chain model for daily rainfall simulation essentially can not incorporate any changes in mean or variance into the model. Here we develop a Non-stationary hidden Markov chain model (NHMM) based stochastic downscaling scheme for simulating the daily rainfall sequences, using general circulation models (GCMs) as inputs. It has been acknowledged that GCMs perform well with respect to annual and seasonal variation at large spatial scale and they stand as one of the primary sources for obtaining forecasts. The proposed model is applied to daily rainfall series at three stations in Nakdong watershed. The model showed a better performance in reproducing most of the statistics associated with daily and seasonal rainfall. In particular, the proposed model provided a significant improvement in reproducing the extremes. It was confirmed that the proposed model could be used as a downscaling model for the purpose of generating plausible daily rainfall scenarios if elaborate GCM forecasts can used as a predictor. Also, the proposed NHMM model can be applied to climate change studies if GCM based climate change scenarios are used as inputs.

Marginal Effect Analysis of Travel Behavior by Count Data Model (가산자료모형을 기초로 한 통행행태의 한계효과분석)

  • 장태연
    • Journal of Korean Society of Transportation
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    • v.21 no.3
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    • pp.15-22
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    • 2003
  • In general, the linear regression model has been used to estimate trip generation in the travel demand forecasting procedure. However, the model suffers from several methodological limitations. First, trips as a dependent variable with non-negative integer show discrete distribution but the model assumes that the dependent variable is continuously distributed between -$\infty$ and +$\infty$. Second, the model may produce negative estimates. Third, even if estimated trips are within the valid range, the model offers only forecasted trips without discrete probability distribution of them. To overcome these limitations, a poisson model with a assumption of equidispersion has frequently been used to analyze count data such as trip frequencies. However, if the variance of data is greater than the mean. the poisson model tends to underestimate errors, resulting in unreliable estimates. Using overdispersion test, this study proved that the poisson model is not appropriate and by using Vuong test, zero inflated negative binomial model is optimal. Model reliability was checked by likelihood test and the accuracy of model by Theil inequality coefficient as well. Finally, marginal effect of the change of socio-demographic characteristics of households on trips was analyzed.