• Title/Summary/Keyword: Model fit

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Measuring the Factors Influencing Customers' Value Perceptions of Foodservice in Namhaean Tourist Area's Restaurant (남해안 관광지 식당의 음식서비스에 대한 내국인 관광객들의 가치 지각에 영향을 주는 요인 분석)

  • Kang, Jong-Heon;Ko, Beom-Seok
    • Journal of the Korean Society of Food Culture
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    • v.23 no.1
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    • pp.48-54
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    • 2008
  • The purpose of this study was to measure the factors influencing customers’ value perception of foodservice in tourist area’s restaurant. A total of 273 questionnaires were completed. Structural equation model was used to measure the causal effects. Results of the study demonstrated that the confirmatory factor analysis model also indicated excellent model fit. The proposed model yielded a significantly better fit to the data than the parsimonious model and extended model. In proposed model, the effects of perceived sacrifice, overall service quality and customer satisfaction on perceived value were statistically significant. The effects of perceived value on loyalty intention were statistically significant. As expected, the overall service quality had a significant effect on customer satisfaction. Moreover, the customer satisfaction played a mediating role in the relationship between overall service quality and loyalty intention.

Symptom Management to Predict Quality of Life in Patients with Heart Failure: A Structural Equation Modeling Approach (증상관리를 통한 심부전 환자의 삶의 질 예측모형)

  • Lee, Ja Ok;Song, Rhayun
    • Journal of Korean Academy of Nursing
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    • v.45 no.6
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    • pp.846-856
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    • 2015
  • Purpose: The focus of this study was on symptom management to predict quality of life among individuals with heart failure. The theoretical model was constructed based on situation-specific theory of heart failure self-care and literature review. Methods: For participants, 241 outpatients at a university hospital were invited to the study from May 19 to July 30, 2014. Data were collected with structured questionnaires and analyzed using SPSSWIN and AMOS 20.0. Results: The goodness of fit index for the hypothetical model was .93, incremental fit index, .90, and comparative fit index, .90. As the outcomes satisfied the recommended level, the hypothetical model appeared to fit the data. Seven of the eight hypotheses selected for the hypothetical model were statistically significant. The predictors of symptom management, symptom management confidence and social support together explained 32% of the variance in quality of life. The 28% of variance in symptom management was explained by symptom recognition, heart failure knowledge and symptom management confidence. The 4% of variance in symptom management confidence was explained by social support. Conclusion: The hypothetical model of this study was confirmed to be adequate in explaining and predicting quality of life among patients with heart failure through symptom management. Effective strategies to improve quality of life among patients with heart failure should focus on symptom management. Symptom management can be enhanced by providing educational programs, encouraging social support and confidence, consequently improving quality of life among this population.

Comparison of the fit of automatic milking system and test-day records with the use of lactation curves

  • Sitkowska, B.;Kolenda, M.;Piwczynski, D.
    • Asian-Australasian Journal of Animal Sciences
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    • v.33 no.3
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    • pp.408-415
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    • 2020
  • Objective: The aim of the paper was to compare the fit of data derived from daily automatic milking systems (AMS) and monthly test-day records with the use of lactation curves; data was analysed separately for primiparas and multiparas. Methods: The study was carried out on three Polish Holstein-Friesians (PHF) dairy herds. The farms were equipped with an automatic milking system which provided information on milking performance throughout lactation. Once a month cows were also subjected to test-day milkings (method A4). Most studies described in the literature are based on test-day data; therefore, we aimed to compare models based on both test-day and AMS data to determine which mathematical model (Wood or Wilmink) would be the better fit. Results: Results show that lactation curves constructed from data derived from the AMS were better adjusted to the actual milk yield (MY) data regardless of the lactation number and model. Also, we found that the Wilmink model may be a better fit for modelling the lactation curve of PHF cows milked by an AMS as it had the lowest values of Akaike information criterion, Bayesian information criterion, mean square error, the highest coefficient of determination values, and was more accurate in estimating MY than the Wood model. Although both models underestimated peak MY, mean, and total MY, the Wilmink model was closer to the real values. Conclusion: Models of lactation curves may have an economic impact and may be helpful in terms of herd management and decision-making as they assist in forecasting MY at any moment of lactation. Also, data obtained from modelling can help with monitoring milk performance of each cow, diet planning, as well as monitoring the health of the cow.

A Model for Predicting Career Satisfaction of Nurses Experiencing Rotation (직무순환을 경험한 간호사의 경력만족 예측모형)

  • Shin, Sook;Yu, Mi
    • Journal of Korean Academy of Nursing
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    • v.47 no.4
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    • pp.551-561
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    • 2017
  • Purpose: This study aimed to present and test a structural model for describing and predicting the factors affecting subjective career satisfaction of nurses experiencing rotation and to develop human resources management strategies for promoting their career satisfaction related to rotation. Methods: In this cross-sectional study, we recruited 233 nurses by convenience sampling who had over 1 year of career experience and who had experienced rotation at least once at G university hospital. Data were collected from August to September in 2016 using self-reported questionnaires. The exogenous variables consisted of rotation perception and rotation stress. Endogenous variables consisted of career growth opportunity, work engagement, and subjective career satisfaction. A hypothetical model was tested by asymptotically distribution-free estimates, and model goodness of fit was examined using absolute fit, incremental fit measures. Results: The final model was approved and had suitable fit. We found that subjective career satisfaction was directly affected by rotation stress (${\beta}=.20$, p=.019) and work engagement (${\beta}=.58$, p<.001), indirectly affected by rotation perception (${\beta}=.43$, p<.001) through career growth opportunity and work engagement. However, there was no total effect of rotation stress on subjective career satisfaction (${\beta}=-.09$, p=.270). Career growth opportunity directly and indirectly affected subjective career satisfaction (${\beta}=.29$, p<.001; ${\beta}=.28$, p<.001). These variables accounted for 65% of subjective career satisfaction. Conclusion: The results of this study suggest that it is necessary to establish systematic and planned criteria for rotation so that nurses can grow and develop through sustained work and become satisfied with their career.

Kinetics of Cr(VI) Sorption/Reduction from Aqueous Solution on Activated Rice Husk

  • El-Shafey, E.I.;Youssef, A.M.
    • Carbon letters
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    • v.7 no.3
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    • pp.171-179
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    • 2006
  • A carbonaceous sorbent was prepared from rice husk via sulphuric acid treatment. After preparation and washing, the wet carbon with moisture content 85% was used in its wet status in this study due to its higher reactivity towards Cr(VI) than the dry carbon. The interaction of Cr(VI) and the carbon was studied and two processes were investigated in terms of kinetics and equilibrium namely Cr(VI) removal and chromium sorption. Cr(VI) removal and chromium sorption were studied at various initial pH (1.6-7), for initial Cr(VI) concentration (100 mg/l). At equilibrium, maximum Cr(VI) removal occurred at low initial pH (1.6-2) where, Cr(III) was the only available chromium species in solution. Cr(VI) removal, at such low pH, was related to the reduction to Cr(III). Maximum chromium sorption (60.5 mg/g) occurred at initial pH 2.8 and a rise in the final pH was recorded for all initial pH studied. For the kinetic experiments, approximate equilibrium was reached in 60-100 hr. Cr(VI) removal data, at initial pH 1.6-2.4, fit well pseudo first order model but did not fit pseudo second order model. At initial pH 2.6-7, Cr(VI) removal data did not fit, anymore, pseudo first order model, but fit well pseudo second order model instead. The change in the order of Cr(VI) removal process takes place in the pH range 2.4-2.6 under the experimental conditions. Other two models were tested for the kinetics of chromium sorption with the data fitting well pseudo second order model in the whole range of pH. An increase in cation exchange capacity, sorbent acidity and base neutralization capacity was recorded for the carbon sorbent after the interaction with acidified Cr(VI) indicating the oxidation processes on the carbon surface accompanying Cr(VI) reduction.

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Synergy and contingency fit analysis for digital convergence value attributes (디지털융합 가치요소의 시너지와 상황 적합 분석)

  • Han, Hyun-Soo;Moon, Tae-Eun
    • Journal of Digital Convergence
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    • v.10 no.11
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    • pp.403-418
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    • 2012
  • In this paper, we attempted to theorize the synergy effect between the value creating attributes for digital convergence model in the service industry. Our investigation is based upon contingency fit theory to understand the strategic fit for the two inherent value attributes of fixed and mobile value, as well as resolving fundamental limitations of service processes. Empirical validation of the derived research model is analyzed using hierarchical regression method. The results indicate that the relative advantage of each value creating attributes are strongly associated with the characteristics of domain service industries, and compatibility is critical to user adoption of convergent service model. Moreover, the less significant statistical impact of the synergy between mobile and fixed value attributes and others implies that each value attribute uniquely contributes to particular IT convergence model, which thereby offers critical insight that focusing the convergent value in conjunction with specific application domain is the most appealing managerial focus. The findings provide useful insight for the further research in IT based industry convergent business model areas.

The high-rate brittle microplane concrete model: Part I: bounding curves and quasi-static fit to material property data

  • Adley, Mark D.;Frank, Andreas O.;Danielson, Kent T.
    • Computers and Concrete
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    • v.9 no.4
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    • pp.293-310
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    • 2012
  • This paper discusses a new constitutive model called the high-rate brittle microplane (HRBM) model and also presents the details of a new software package called the Virtual Materials Laboratory (VML). The VML software package was developed to address the challenges of fitting complex material models such as the HRBM model to material property test data and to study the behavior of those models under a wide variety of stress- and strain-paths. VML employs Continuous Evolutionary Algorithms (CEA) in conjunction with gradient search methods to create automatic fitting algorithms to determine constitutive model parameters. The VML code is used to fit the new HRBM model to a well-characterized conventional strength concrete called WES5000. Finally, the ability of the new HRBM model to provide high-fidelity simulations of material property experiments is demonstrated by comparing HRBM simulations to laboratory material property data.

Optimizing Food Processing through a New Approach to Response Surface Methodology

  • Sungsue Rheem
    • Food Science of Animal Resources
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    • v.43 no.2
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    • pp.374-381
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    • 2023
  • In a previous study, 'response surface methodology (RSM) using a fullest balanced model' was proposed to improve the optimization of food processing when a standard second-order model has a significant lack of fit. However, that methodology can be used when each factor of the experimental design has five levels. In response surface experiments for optimization, not only five-level designs, but also three-level designs are used. Therefore, the present study aimed to improve the optimization of food processing when the experimental factors have three levels through a new approach to RSM. This approach employs three-step modeling based on a second-order model, a balanced higher-order model, and a balanced highest-order model. The dataset from the experimental data in a three-level, two-factor central composite design in a previous research was used to illustrate three-step modeling and the subsequent optimization. The proposed approach to RSM predicted improved results of optimization, which are different from the predicted optimization results in the previous research.

Testing Goodness-of-Fit for No Effect Models

  • Sungho Lee;Jongtae Kim;GyoungAe Moon
    • Communications for Statistical Applications and Methods
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    • v.5 no.3
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    • pp.935-944
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    • 1998
  • This paper investigates the problem of goodness of fit tests for no effect model. The proposed test statistic $Z_{mn}$ is obtained by multiplying constant on the model free curve estimation techniques. The small and large sample properties of$Z_{mn}$ are investigated and the good results of power studies for the proposed test are illustrated.

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Suppression and Collapsibility for Log-linear Models

  • Sun, Hong-Chong
    • Communications for Statistical Applications and Methods
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    • v.11 no.3
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    • pp.519-527
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    • 2004
  • Relationship between the partial likelihood ratio statistics for logisitic models and the partial goodness-of-fit statistics for corresponding log-linear models is discussed. This paper shows how definitions of suppression in logistic model can be adapted for log-linear model and how they are related to confounding in terms of collapsibility for categorical data. Several $2{times}2{times}2$ contingency tables are illustrated.