• 제목/요약/키워드: Model fit

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모바일 SFA(mSFA) 시스템의 수용 요인 및 도입 성과에 관한 연구 (A Study on the Adoption Factors and Performance Effects of Mobile Sales Force Automation Systems)

  • 김동현;이선로
    • 경영과학
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    • 제24권1호
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    • pp.127-145
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    • 2007
  • This study attempts to examine the acceptance factors of mSFA systems based on the innovation diffusion and technology acceptance model, and to measure the performance effects of mSFA systems using BSC metrics. Results show that (1) the characteristics of mobility and interactivity have positive impacts on perceived usefulness, ease of use, and professional fit. But the characteristics of personal identity were not perceived as useful due to users' negative feelings about privacy infringement and surveillance. (2) Job fit has positive impacts on perceived usefulness and professional fit. (3) Perceived usefulness, ease of use, and professional fit positively influence the degree of users' dependence on mSFA systems, which have positive impacts on users' performance measured by the personal BSC metrics including perspectives of finance, customer, internal process, and learning and growth.

일 도시 지역 중년 여성의 정신건강상태 예측모형 (Prediction Model on Mental Health Status in Middle-aged Women of an Urban Area)

  • 이평숙;손정남;이용미;강현철
    • 대한간호학회지
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    • 제35권2호
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    • pp.239-251
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    • 2005
  • Purpose: This study was designed to construct a structural model for explaining mental health status in middle - aged women. Methods: The data was collected by self - reported questionnaires from 206 middle - aged women in Seoul. Data analysis was done with the SAS pc program for descriptive statistics and a PC - LISREL Program for finding the best fit model which assumes causal relationships among variables. Results: The overall fit of the hypothetical model to the data was good, but paths and variables of the model were modified by considering theoretical implications and statistical significances of parameter estimates. Thus it was modified by excluding 3 paths, The modified model showed was good fit to the data($x^2=177.55$, p=.00), GFI=0.908, AGFI=0.860, RMR=0.013, NFI=0.972, NNFI=0.982). Perceived stress, anger expression method, and self -esteem were found to have direct effects on mental health status in middle - aged women. These predictive variables of mental health status explained $66.6\%$ of the model. Conclusion: Programs to enhance mental health status in middle - aged women should include stress management skill, anger expression skill, and self -esteem enhancement skills to be effective.

서브쿨드 비등 영역에서의 기포계수 계산에 관한 연구 (The Prediction of Void Fraction in the Subcooled Boiling Region)

  • Goon Cherl Park
    • Nuclear Engineering and Technology
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    • 제16권4호
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    • pp.195-201
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    • 1984
  • 축방향 비균일 열유량을 가지는 서브쿨드 비등영역에서 첨단적인 mechanistic 모델을 사용하여 기포계수를 정확히 계산하고저 한다. 이 모델에서는 Lahey/Ohama model에서 구한 기포계수에 의존하는 drift-flux계수를 사용하였고 또한 실제 실험치와 비교하여 질량유량에 의존하는 응축계수의 상관식을 구하여 사용하였다. 이 모델은 고 정확도를 증명하기 위해 잘 알려진 실험치들과 비교되었고 최종적으로 고리 1호기 1주기의 고온 연료집합체 기포계수를 계산하므로서 profilefit 모델과 비교되었다. 이러한 계산결과는 실험치와 잘 일치하고 있으며 profile-fit model은 서브쿨드 비등영역에서 기포 계수를 낮게 계산하고 있음이 밝혀졌다.

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단일방정식과 관련방정식체계를 적용한 소비지출 함수의 모델 적합성 비교 (A Comparison of the Goodness-of-Fit between Two Models of Expenditure Function: a Single-Equation Model versus a Complete- System-of-Demand-Equation Model)

  • 황덕순;김숙향
    • 가정과삶의질연구
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    • 제20권1호
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    • pp.45-56
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    • 2002
  • The main purposes of this article are to introduce the theoretical backgrounds and empirical application methods of two different Models for the function of expenditure, and to compare the goodness-o(-fit of the two models: a single-equation model and a complete-system-of-demand-equation model. For the empirical analysis of the single-equation model, a linear formula and a double-leg formula were employed. In order to test the complete-system-of-demand-equation model empirically, the \"Linear Approximation/Almost Ideal Demand System (LA/AIDS)" was used. The independent variables were the total living expense and expenditure categories Price index. The data used in this study were obtained from the quarterly statistics of "The Annual Report on the Urban Family Income and Expenditure Survey (Dosigagyeyonbo)" and "The Annual Report on the Consumer Price Index (Sobijamulgajaryo)," for the years 1994 to 1997. The goodness-of-fit (R-square) was higher with the complete-system-of-demand-equation model than with the single-equation model for the budget share on food (excluding eating-out expenses) and for the share on cultural and recreational activities. However, there was no difference between the two models in terms of the proportion of the expenditure on automobile fuel.fuel.

Nonlinear Regression on Cold Tolerance Data for Brassica Napus

  • Yang, Woohyeong;Choi, Myeong Seok;Ahn, Sung Jin
    • Journal of the Korean Data Analysis Society
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    • 제20권6호
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    • pp.2721-2731
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    • 2018
  • This study purposes to derive the predictive model for the cold tolerance of Brassica napus, using the data collected in the Tree Breeding Lab of Gyeongsang National University during July and August of 2016. Three Brassica napus samples were treated at each of low temperatures from $4^{\circ}C$ to $-12^{\circ}C$ by decrement of $4^{\circ}C$, step by step, and electrolyte leakage levels were measured at each stage. Electrolyte leakages were observed tangibly from $-4^{\circ}C$. We tried to fit the six nonlinear regression models to the electrolyte leakage data of Brassica napus: 3-parameter logistic model, baseline logistic model, 4-parameter logistic model, (4-1)-parameter logistic model, 3-parameter Gompertz model, and (3-1)-parameter Gompertz model. The baseline levels of the electrolyte leakage estimated by these models were 4.81%, 4.07%, 4.19%, 4.07%, 4.55%, and 0%, respectively. The estimated median lethal temperature, LT50, were $-5.87^{\circ}C$, $-6.31^{\circ}C$, $-6.05^{\circ}C$, $-6.35^{\circ}C$, $-4.98^{\circ}C$, and $-5.15^{\circ}C$, respectively. We compared and discussed the measures of goodness of fit to select the appropriate nonlinear regression model.

류마티스 관절염 환자가 지각하는 불확실성에 관한 모형 구축 (Model Construction of Perceived Uncertainty in Rheumatoid Arthritis Patients)

  • 유경희;이은옥
    • 근관절건강학회지
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    • 제5권1호
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    • pp.7-25
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    • 1998
  • Rheumatoid arthritis, unlike other chronic diseases, causes the patients to experience uncertainty in their daily lives and thus to feel threat on their emotional comfort because of inconsistent and unpredictable symptoms such as pain. Therefore, a theoretical framework is needed for explanation of uncertainty in patients having rheumatoid arthritis. A hypothetical model was constructed on the basis of Mishel's Uncertainty Theory and other literature review. The model included 9 theoretical concepts and 19 paths. Subjects of the study constituted 330 partients who visited outpatient clinics of two university hospitals and one general hospital in Seoul. Self report questionnaires were used to measure the variables affecting uncertainty. Reliability coefficients of these instruments were found Cronbach's Alpha=$.70{\sim}.94$. In data analysis, SAS program and PC-LISREL 8.03 computer program were utilized for descriptive statistics and covariance structure analysis. The results of covariance structure analysis for model fitness were as follows : 1) Hypothetical model showed a good fit to the empirical data : Chi-square($X^2$)=41.81 (df=11, P=.000), Goodness of Fit Index=.974, Root Mean Square Residual=.049, Normed Fit Index=.928, Non Normed Fit Index=.814. 2) For the validity and the parcimony of model, a modified model was constructed by appending 2 paths and deleting 5 paths according to the criteria of statistical significance and meaningfulness. 3) The results of hypothesis testing were as follows : (1) Educational level, event familiarity and severity of illness had a direct effect on uncertainty : Event congruency had both direct and indirect effect on uncertainty : Credible authority and symptom consistency had a nonsignificant direct effect on uncertainty, (2) Illness duration, symptom consistency, and event congruency had a direct effect on severity of illness ; Credible authority had a both direct and indirect effect on severity of illness ; Event congruency had the greatest effect on severity of illness, and event familiarity had a nonsignificant direct effect on severity of illness.

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목질계 바이오매스 유래 바이오차의 특성과 메틸렌블루 흡착 효과 (Characteristics of Biochar Derived from Lignocellulosic Biomass and Effect of Adsorption of Methylene Blue)

  • 신윤정;송대연;이은주;이재원
    • 공업화학
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    • 제34권2호
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    • pp.153-160
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    • 2023
  • 본 논문에서는 미이용 바이오매스로부터 바이오차를 생산하고 메틸렌블루 흡착 특성을 평가하였다. 바이오매스는 주로 셀룰로오스, 헤미셀룰로오스, 리그닌으로 구성되어 있으며 회분의 함량은 벌채부산물에서 가장 높았다. 탄화 온도가 증가할수록 탄화 수율은 감소하였으며, 수소와 산소 함량도 감소하였다. 반면, 탄소 함량은 증가하였다. 탄화 온도가 증가할수록 바이오차의 비표면적과 미세기공은 증가하였다. 바이오차 비표면적은 탄화 온도 600 ℃에서 가장 높았다(216.15~301.80 m2 /g). 600 ℃에서 탄화한 바이오차를 이용하여 메틸렌블루 흡착 실험을 수행한 결과, 참나무, 벌채부산물, 사과 전정가지의 흡착 거동은 Freundlich model, 복숭아 전정가지는 Langmuir model에 적합하였다. 흡착 동역학에서 참나무와 복숭아 전정가지는 pseudo-first-order model, 벌채부산물과 사과 전정가지는 pseudo-second-order model에 적합하였다.

호흡기 보호구 착용시 움직임과 매일 착용에 따른 Fit Factors의 변화 (Day-to-Day and Movement-Dependent Variations of Quantitative Fit Tests for an Individual Wearing A Respirator)

  • 한돈희
    • 한국산업보건학회지
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    • 제6권2호
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    • pp.176-186
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    • 1996
  • The fit of a respirator to the face of an individual can be determined by a qualitative fit test (QLFT) or a quantitative fit test (QNFT). The pass/fail decision from a QLFT or QNFT for the same respirator on the same individual may vary from one wearing to the next, because the human facial features are complex and the respirator may not fit to the face in the same way every time it is worn. This study reports how the fit factors (FF) resulting from a QNFT on an individual vary from day to day and depend on the movements in the six fit test exercises. The reported FFs provide an objective and numerical basis (FF) which does not depend on the subject's voluntary or involuntary response. Four half-mask (H1-H4) and four full-facepiece respirators (F1-F4) were fit tested on one wearer 10 times a day for 5 days with a PortaCount (model 8010, TSI). The FFs obtained for each set of 10 fit tests on a specific day and 50 fit tests on five days involving one of the six exercise regimes have been recorded as log-normal distributions. All of the geometric standard deviations (GSD) of the overall FFs varied widely among every wearing and day except for H1 and F3, and the variability of the half-mask respirators was larger than that of the full-facepiece respirators. Among the six exercise regimes, reading or talking (RT) had markedly the lowest exercise FFs on the tested individual. Generally, there were significant differences between the first normal breathing (NB1) FFs and the remaining exercise FFs.

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THE DEVELOPMENT OF A ZERO-INFLATED RASCH MODEL

  • Kim, Sungyeun;Lee, Guemin
    • 한국수학교육학회지시리즈B:순수및응용수학
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    • 제20권1호
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    • pp.59-70
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    • 2013
  • The purpose of this study was to develop a zero-inflated Rasch (ZI-Rasch) model, a combination of the Rasch model and the ZIP model. The ZI-Rasch model was considered in this study as an appropriate alternative to the Rasch model for zero-inflated data. To investigate the relative appropriateness of the ZI-Rasch model, several analyses were conducted using PROC NLMIXED procedures in SAS under various simulation conditions. Sets of criteria for model evaluations (-2LL, AIC, AICC, and BIC) and parameter estimations (RMSE, and $r$) from the ZI-Rasch model were compared with those from the Rasch model. In the data-model fit indices, regardless of the simulation conditions, the ZI-Rasch model produced better fit statistics than did the Rasch model, even when the response data were generated from the Rasch model. In terms of item parameter ${\lambda}$ estimations, the ZI-Rasch model produced estimates similar to those of the Rasch model.

Accuracy of Data-Model Fit Using Growing Levels of Invariance Models

  • Almaleki, Deyab A.
    • International Journal of Computer Science & Network Security
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    • 제21권12호
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    • pp.157-164
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    • 2021
  • The aim of this study is to provide empirical evaluation of the accuracy of data-model fit using growing levels of invariance models. Overall model accuracy of factor solutions was evaluated by the examination of the order for testing three levels of measurement invariance (MIV) starting with configural invariance (model 0). Model testing was evaluated by the Chi-square difference test (∆𝛘2) between two groups, and root mean square error of approximation (RMSEA), comparative fit index (CFI), and Tucker-Lewis index (TLI) were used to evaluate the all-model fits. Factorial invariance result revealed that stability of the models was varying over increasing levels of measurement as a function of variable-to-factor ratio (VTF), subject-to-variable ratio (STV), and their interactions. There were invariant factor loadings and invariant intercepts among the groups indicating that measurement invariance was achieved. For VTF ratio (3:1, 6:1, and 9:1), the models started to show accuracy over levels of measurement when STV ratio was 6:1. Yet, the frequency of stability models over 1000 replications increased (from 69% to 89%) as STV ratio increased. The models showed more accuracy at or above 39:1 STV.