• Title/Summary/Keyword: Goodness of fit

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Non-linear modelling to describe lactation curve in Gir crossbred cows

  • Bangar, Yogesh C.;Verma, Med Ram
    • Journal of Animal Science and Technology
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    • v.59 no.2
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    • pp.3.1-3.7
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    • 2017
  • Background: The modelling of lactation curve provides guidelines in formulating farm managerial practices in dairy cows. The aim of the present study was to determine the suitable non-linear model which most accurately fitted to lactation curves of five lactations in 134 Gir crossbred cows reared in Research-CumDevelopment Project (RCDP) on Cattle farm, MPKV (Maharashtra). Four models viz. gamma-type function, quadratic model, mixed log function and Wilmink model were fitted to each lactation separately and then compared on the basis of goodness of fit measures viz. adjusted $R^2$, root mean square error (RMSE), Akaike's Informaion Criteria (AIC) and Bayesian Information Criteria (BIC). Results: In general, highest milk yield was observed in fourth lactation whereas it was lowest in first lactation. Among the models investigated, mixed log function and gamma-type function provided best fit of the lactation curve of first and remaining lactations, respectively. Quadratic model gave least fit to lactation curve in almost all lactations. Peak yield was observed as highest and lowest in fourth and first lactation, respectively. Further, first lactation showed highest persistency but relatively higher time to achieve peak yield than other lactations. Conclusion: Lactation curve modelling using gamma-type function may be helpful to setting the management strategies at farm level, however, modelling must be optimized regularly before implementing them to enhance productivity in Gir crossbred cows.

A Study on the Socio-economic Characteristics of the Angler Population and the Estimation of A Fishing Frequency Function (유어낚시인구의 사회경제학적 특성과 출조빈도함수의 추정에 관한 연구)

  • Park Cheol-Hyung
    • The Journal of Fisheries Business Administration
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    • v.36 no.1 s.67
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    • pp.81-101
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    • 2005
  • This article is to estimate the fishing frequency function in Korean recreational fishery with respect to socio-economic characteristics of anglers. First, the study described the characteristics of the entire angler population on the view points of 9 socio-economic variables. And then, the study divided the total angler population into three groups of in-land, sea, and mixed angler populations in order to investigate the differences in their characteristics. The study could confirm the existence of differences in regions, size of regions, and educational levels between the in - land and the sea angler populations by testing heterogeneity in the frequency table. The fishing frequency function is estimated using Poisson regression model in order to accomodate the count data(non-negative discrete random variable) aspects of the fishing frequency. However, the model specification error is found due to overdispersion of data. The model exhibits the lack of goodness of fit. The negative binomial regression model is adopted to cure the overdispersion of the data as an alternative estimation methodology. Finally, the study can confirm overdispersion does not exist in the model any more and the goodness of fit improved significantly to the reasonable level. The results of estimation of fishing frequency population modeled by the negative binomial regression models are following. The three variables of region, sex, and education have effects on the decision making process of fishing frequency in the case of in-land recreation fishery. On the other hand, the three variables of sex, age, and marriage status do the same job in the case of sea angler population. Among the left-over variables, both income and use of Internet variables now affect on the process in mixed angler population. Finally, the results of whole angler population show that all of the previous variables are proven to be statistically significant due to the summation of data with all three sub-groups of angler population.

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Multivariate design estimations under copulas constructions. Stage-1: Parametrical density constructions for defining flood marginals for the Kelantan River basin, Malaysia

  • Latif, Shahid;Mustafa, Firuza
    • Ocean Systems Engineering
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    • v.9 no.3
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    • pp.287-328
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    • 2019
  • Comprehensive understanding of the flood risk assessments via frequency analysis often demands multivariate designs under the different notations of return periods. Flood is a tri-variate random consequence, which often pointing the unreliability of univariate return period and demands for the joint dependency construction by accounting its multiple intercorrelated flood vectors i.e., flood peak, volume & durations. Selecting the most parsimonious probability functions for demonstrating univariate flood marginals distributions is often a mandatory pre-processing desire before the establishment of joint dependency. Especially under copulas methodology, which often allows the practitioner to model univariate marginals separately from their joint constructions. Parametric density approximations often hypothesized that the random samples must follow some specific or predefine probability density functions, which usually defines different estimates especially in the tail of distributions. Concentrations of the upper tail often seem interesting during flood modelling also, no evidence exhibited in favours of any fixed distributions, which often characterized through the trial and error procedure based on goodness-of-fit measures. On another side, model performance evaluations and selections of best-fitted distributions often demand precise investigations via comparing the relative sample reproducing capabilities otherwise, inconsistencies might reveal uncertainty. Also, the strength & weakness of different fitness statistics usually vary and having different extent during demonstrating gaps and dispensary among fitted distributions. In this literature, selections efforts of marginal distributions of flood variables are incorporated by employing an interactive set of parametric functions for event-based (or Block annual maxima) samples over the 50-years continuously-distributed streamflow characteristics for the Kelantan River basin at Gulliemard Bridge, Malaysia. Model fitness criteria are examined based on the degree of agreements between cumulative empirical and theoretical probabilities. Both the analytical as well as graphically visual inspections are undertaken to strengthen much decisive evidence in favour of best-fitted probability density.

A Study on Statistical Distribution of Muzzle Velocity of 155mm Propelling Charge (155mm 추진장약 포구속도의 확률분포 특성 연구)

  • Park, Sung-Ho;Park, No-Seok;Choi, Beong-Doo;Kim, Jae-Hoon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2009.11a
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    • pp.339-343
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    • 2009
  • The aim of the study was to investigate the statistical distribution of muzzle velocity of 155mm propelling charge K676 which is for the use of K9, a korean 155mm self-propelled artillery. A plenty of muzzle velocity data were collected from lot assessment test of propelling charge. The muzzle velocity of each test round is compensated by reference round. In the present work, the detailed statistical analysis of the muzzle velocity data is carried out using probability models including normal, Weibull 2-parameter and Weibull 3-parameter distributions. The results of goodness of fit test showed that the normal distribution described more appropriately the experimentally measured muzzle velocity data and the Weibull distribution is also applicable. The coefficient of variation showed that the mass production capability of each propelling charge lot has been maintained.

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Verification of Validity of MPM II for Neurological Patients in Intensive Care Units (신경계중환자의 사망예측모델(Mortality Probability Model II)에 대한 타당도 검증)

  • Kim, Hee-Jeong;Kim, Kyung-Hee
    • Journal of Korean Academy of Nursing
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    • v.41 no.1
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    • pp.92-100
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    • 2011
  • Purpose: Mortality Provability Model (MPM) II is a model for predicting mortality probability of patients admitted to ICU. This study was done to test the validity of MPM II for critically ill neurological patients and to determine applicability of MPM II in predicting mortality of neurological ICU patients. Methods: Data were collected from medical records of 187 neurological patients over 18 yr of age who were admitted to the ICU of C University Hospital during the period from January 2008 to May 2009. Collected data were analyzed through $X^2$ test, t-test, Mann-Whiteny test, goodness of fit test, and ROC curve. Results: As to mortality according to patients' general and clinically related characteristics, mortality was statistically significantly different for ICU stay, hospital stay, APACHE III score, APACHE predicted death rate, GCS, endotracheal intubation, and central venous catheter. Results of Hosmer-Lemeshow goodness-of-fit test were MPM $II_0$ ($X^2$=0.02, p=.989), MPM $II_24$ ($X^2$=0.99 p=.805), MPM $II_48$ ($X^2$=0.91, p=.822), and MPM $II_72$ ($X^2$=1.57, p=.457), and results of the discrimination test using the ROC curve were MPM $II_0$, .726 (p<.001), MPM $II_24$, .764 (p<.001), MPM $II_48$, .762 (p<.001), and MPM $II_72$, .809 (p<.001). Conclusion: MPM II was found to be a valid mortality prediction model for neurological ICU patients.

Evaluation of Applicability of SWAT-CUP Program for Hydrologic Parameter Calibration in Hardware Watershed (Hardware 유역의 수문매개변수 보정을 위한 SWAT-CUP 프로그램의 적용성 평가)

  • Sang Min, Kim
    • Journal of The Korean Society of Agricultural Engineers
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    • v.59 no.3
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    • pp.63-70
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    • 2017
  • The purpose of this study was to calibrate the hydrologic parameters of SWAT model and analyze the daily runoff for the study watershed using SWAT-CUP. The Hardware watershed is located in Virginia, USA. The watershed area is $356.15km^2$, and the land use accounts for 73.4 % of forest and 23.2 % of pasture. Input data for the SWAT model were obtained from the digital elevation map, landuse map, soil map and others. Water flow data from 1990 to 1994 was used for calibration and from 1997 to 2005 was for validation. The SUFI-2 module of the SWAT-CUP program was used to calibrate the hydrologic parameters. The parameters were calibrated for the highly sensitive parameters presented in previous studies. The P-factor, R-factor, $R^2$, Nash-Sutcliffe efficiency (NS), and average flow were used for the goodness-of-fit measures. The applicability of the model was evaluated by sequentially increasing the number of applied parameters from 4 to 11. In this study, 10-parameter set was accepted for calibration in consideration of goodness-of-fit measures. For the calibration period, P-factor was 0.85, R-factor was 1.76, $R^2$ was 0.51 and NS was 0.49. The model was validated using the adjusted ranges of selected parameters. For the validation period, P-factor was 0.78, R-factor was 1.60, $R^2$ was 0.60 and NS was 0.57.

Evaluation and Analysis of Gwangwon-do Landslide Susceptibility Using Logistic Regression (로지스틱 회귀분석 기법을 이용한 강원도 산사태 취약성 평가 및 분석)

  • Yeon, Young-Kwang
    • Journal of the Korean Association of Geographic Information Studies
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    • v.14 no.4
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    • pp.116-127
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    • 2011
  • This study conducted landslide susceptibility analysis using logistic regression. The performance of prediction model needs to be evaluated considering two aspects such as a goodness of fit and a prediction accuracy. Thus to gain more objective prediction results in this study, the prediction performance of the applied model was evaluated considering two such evaluation aspects. The selected study area is located between Inje-eup and Buk-myeon in the middle of Kwangwon. Landslides in the study area were caused by heavy rain in 2006. Landslide causal factors were extracted from topographic map, forest map and soil map. The evaluation of prediction model was assessed based on the area under the curve of the cumulative gain chart. From the results of experiments, 87.9% in the goodness of fit and 84.8% in the cross validation were evaluated, showing good prediction accuracies and not big difference between the results of the two evaluation methods. The results can be interpreted in terms of the use of environmental factors which are highly related to landslide occurrences and the accuracy of the prediction model.

A Study on the Application ratio of Directional wind speeds Characteristics by Gumbel Model Simulation Using Directional wind Patterns (풍향패턴에 따른 굼벨 모델 시뮬레이션에 의한 풍향풍속성의 적용율 평가에 관한 연구)

  • Chung, Yung-Bea
    • Journal of Korean Society of Steel Construction
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    • v.22 no.6
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    • pp.573-580
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    • 2010
  • In this study, an assessment method that considers the effects of directional wind speeds on buildings or structures that are sensitive to wind is proposed. Also, the basic characteristics of directional wind speeds were assessed by means of local annual maximum wind speeds. From the method of assessment of the characteristics of directional wind speeds, their goodness-of-fit was verified by applying extreme value distribution to the data on annual maximum wind speeds from the Korea Meteorological Administration. To consider the characteristics of directional winds, an assessment method is suggested that divides the directional wind pattern of each directional wind speed into four groups. From the study results, all the data on directional wind speeds based on the Gumbel distribution were examined using data on annual maximum wind speeds from Seoul, Tongyung, and Incheon. Since the Gumbel model of all directional wind speeds has independent probability characteristics that govern the 4 directional wind pattern groups, the application ratio proposed was based on the assessment of these four groups. According to the goodness-of-fit of the data on the annual maximum wind speeds based on the Gumbel distribution, new application ratios were proposed that consider the directional wind speeds in Seoul, Tongyung, and Incheon.

The influence of consumers' personality types on perceived risk to loyalty and purchase intentions - Focusing on the judging and perceiving types of MBTI - (소비자의 성격유형별 위험지각이 충성도 및 구매의도에 미치는 영향 - MBTI의 판단유형과 인식유형을 중심으로 -)

  • Yu, Jihun;Lee, Sang In
    • The Research Journal of the Costume Culture
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    • v.25 no.5
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    • pp.682-693
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    • 2017
  • The purpose of the study was to compare two different MBTI personality types by evaluating the influence of perceived risk on brand and store loyalty and purchase intention. 340 questionnaires were used for the analysis. For statistical analysis, SPSS 20.0 and AMOS 20.0 were performed, and frequency tests, reliability analyses and Structural Equation Modeling were used. The results of SEM analysis, confirmed that one question of brand loyalty and one question of store loyalty were inappropriate for this study. Thus, these two questions were removed and the research model was modified. To determine the goodness of fit of the research model, convergent validity was tested. Most items fell into the goodness of fit, and the average coefficient was fulfilled. According to the results of a path coefficient analysis for the Judging type, perceived risk has a significant influence on brand loyalty and brand loyalty also affected store loyalty. Furthermore, brand loyalty and store loyalty have a significant effect on purchase intentions, but perceived risk did not affect brand loyalty for the Perceiving type. Brand loyalty influences store loyalty and purchase intentions, but store loyalty did not influence purchase intentions. As a result of this study, it is concluded that considering consumers' personality types is critical to developing strategies that enhance brand loyalty.

Mediating Effects of Self-esteem on the Convergent Relationship between Respect for Human Rights and School Adjustment of Adolescents (청소년의 인권존중과 학교적응의 융합적 관계에서 자아존중감의 매개효과)

  • Cha, Yu-Mi;Cha, Sung-Hyun
    • Journal of the Korea Convergence Society
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    • v.10 no.10
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    • pp.207-214
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    • 2019
  • The purpose of the study was to examine the mediating effect of self-esteem on the convergent relationship between respect for human rights and school adjustment of adolescents. Data came from the Korean Survey on the rights of Children and Youth in 2016 and a total of 2,366 of the 2nd grade students in middle school were employed. Structural equation modeling approach was utilized to test the goodness of research model fit and especially the mediating effect was tested by bootstrapping method. Results showed that goodness of model fit was acceptable and self-esteem mediated the convergent relationship between respect for human rights and school adjustment of adolescents. This indicates that the more experiences in respect for human rights and the higher their self-esteem students have, the better school adjustment they acquire. The results of the study imply that it is necessary to expand the human rights education for teachers and develop a new educational program that links between respect for human rights and self-esteem.