habib jafari - Academia.edu (original) (raw)

Papers by habib jafari

Communications in statistics. Theory and methods/Communications in statistics, theory and methods, Mar 19, 2024

Arabian Journal of Geosciences

International Journal of Geosynthetics and Ground Engineering

Applied Mathematics-a Journal of Chinese Universities Series B, 2013

During sampling, a researcher may sometimes encounter a population, in wh ich selection chance of... more During sampling, a researcher may sometimes encounter a population, in wh ich selection chance of each one of the samples is not equal; in such a situation, it is better to utilize weighted distribution instead of main distribution for data analysis. Accordingly, considering a weighted distribution (for a state in which response variable has such a distribution in a linear regression model) and also a mu ltip le regression (two regressors) model, this paper proposed an appropriate design (for estimating the parameters) using the known optimality design (D-optimality) to obtain optimality of the presented design.

Today, entrepreneurial skills are considered as the appropriate strategy for the expanding of pro... more Today, entrepreneurial skills are considered as the appropriate strategy for the expanding of productivity and overall development of any organization. Some scholars believe that the entrepreneurial skills, promote efficiency in different levels in organizations. The aim of this study was to investigate the relationship between organizational justice and organizational commitment with entrepreneurial skills in Urmia industrial Estate’s Companies. The results showed that there is a significant relationship between procedural, distributive and interactional components of organizational justice and affective, normative and continuance dimensions of organizational commitment with entrepreneurial skills. Regression analysis also showed that procedural and distributive components of organizational justice are better predictor for entrepreneurial skills and affective and continuance dimensions of organizational commitment are better predictor for entrepreneurial skills than others. The res...

One of the practical and important issue in statistics is the fitness of regression models. Optim... more One of the practical and important issue in statistics is the fitness of regression models. Optimal design is a way to obtain suitable fitness of this type of models. In addition, we need to use some criteria for attaining optimal design in regression models. The D-optimality criterion is one of the most famous criteria which is used here. An appropriate method to obtain the optimal designs is the Bayesian method that need to the prior distribution for the parameters of the model (coefficient regression). In this paper, by using Bayesian methods, D-optimal designs are obtained for quadratic beta regression model. Also, uniform and normal distributions are considered as the prior distributions and obtained results are analyzed.

In this paper we calculate the information matrix for a three-level nested Multinomial logit mode... more In this paper we calculate the information matrix for a three-level nested Multinomial logit model and derive the locally D-optimal design to estimate the parameter vector.

The present paper aims at studying the impact of organizational culture and social capital on org... more The present paper aims at studying the impact of organizational culture and social capital on organizational entrepreneurship of the personnel of Iraq's Babel and Kermanshah's Razi Universities.The methodology is descriptive-Survey with respect to the purpose of the study.The statistical society of the study contains 509 personnel of Iraq's Babel and Kermansha's Razi Universities, 219 of which selected as the sample of the study through stratified random sampling. Robins' Organizational Culture, Onagh's Social Capital and Margrit Hill's Organizational Entrepreneurship questionnaires were the data collection tools. Using Chronbach's Alpha Ratio the consistency of the questionnaires were computed 95%, 91% and 96% respectively for Organizational Culture questionnaire, Social Capital questionnaire and Organizational Entrepreneurship questionnaire.This paper addresses the impact of organizational culture and social capital on organizational entrepreneurshi...

Communications in Statistics - Simulation and Computation, 2021

A two-layered product can be molded through various processes. Rotational molding is a useful pro... more A two-layered product can be molded through various processes. Rotational molding is a useful process used to produce a two-layered thermoplastic product. However, the rotational molding requires a complicated technique as well as special and expensive equipment. The particle size and size distribution of plastic are one of the process criteria. In this research we studied the possibility of using the one-step rotational molding technique to produce a two-layered molding of polypropylene (PP) and polyethylene (PE) by focusing on the effects of different particle shapes, sizes of PP and the rotational speed. The axial powder flow apparatus was used for molding study. The particle sizes of PP were determined as equal as, 2 and 4 times as large than those of PE. PP particles were determined to be a spherical and non-spherical shape, and the rotational speed was compared for 7 and 60 rpm. The two materials were mixed in a ratio of 50:50 (wt%) by a dry blending method. The phenomenon happening during the molding was observed and recorded in real time by a high-resolution camera. After molding, the specimens were investigated in terms of their layer separation, thermal property, surface quality, thickness distribution and mechanical property. The results of the experiment indicated that the two-layered molding of PP and PE using an uncomplicated technique for rotational molding had a high probability of success. Particularly, in the case of PP with a spherical shape, it was 4 times as large as that of PE at the rotational speed of 7 rpm. It was also found that an increase in rotational speed resulted in a more chance of two-layered separation.

Journal of Mathematics and Computer Science, 2014

Journal of Statistical Computation and Simulation, 2016

ABSTRACT According to investigated topic in the context of optimal designs, various methods can b... more ABSTRACT According to investigated topic in the context of optimal designs, various methods can be used to obtain optimal design, of which Bayesian method is one. In this paper, considering the model and the features of the information matrix, this method (Bayesian optimality criterion) has been used for obtaining optimal designs which due to the variation range of the model parameters, prior distributions such as Uniform, Normal and Exponential have been used and the results analysed.

PLOS ONE, 2022

Anthropometry is a Greek word that consists of the two words “Anthropo” meaning human species and... more Anthropometry is a Greek word that consists of the two words “Anthropo” meaning human species and “metery” meaning measurement. It is a science that deals with the size of the body including the dimensions of different parts, the field of motion and the strength of the muscles of the body. Specific individual dimensions such as heights, widths, depths, distances, environments and curvatures are usually measured. In this article, we investigate the anthropometric characteristics of patients with chronic diseases (diabetes, hypertension, cardiovascular disease, heart attacks and strokes) and find the factors affecting these diseases and the extent of the impact of each to make the necessary planning. We have focused on cohort studies for 10047 qualified participants from Ravansar County. Machine learning provides opportunities to improve discrimination through the analysis of complex interactions between broad variables. Among the chronic diseases in this cohort study, we have used th...

Malaysian Online Journal of Educational Management