Iran and COVID-19: A Bottom-up,Faith-Driven,Citizen-Supported Response

Public Organization Review - The COVID-19 pandemic cast doubts on governments' traditional crisis responses and sparked a surge in citizen-led, participatory, bottom-up responses. Iran's...     

The competing risks analysis for parallel and series systems using Type-II progressive censoring

Abstract

Recently, the study of the lifetime of systems in reliability and survival analysis in the presence of several causes of failure (competing risks) has attracted attention in the literature. In this paper, series and parallel systems with exponential lifetime for each item of the system are considered. Several causes of failure independently affect lifetime distributions and observations of failure times of the systems are considered under progressive Type-II censored scheme. For series systems, the maximum likelihood estimates of parameters are computed and confidence intervals for parameters of the model are obtained using Fisher information matrix. For parallel systems, the generalized EM algorithm which uses the Newton-Raphson algorithm inside the EM algorithm is used to compute the maximum likelihood estimates of parameters. Also, the standard errors of the maximum likelihood estimates are computed by using the supplemented EM algorithm. The simulation study confirms the good performance of the introduced approach.     

Dimensions of Identity Development Scale: Confirmatory factor analysis,gender invariance,and external validity of the Persian version

The present study was conducted to examine the psychometric properties and gender invariance of the Iranian version of the Dimensions of Identity Development Scale (DIDS). A total of 1453 adolescents (50.8% female; 14–18 years old, mean = 15.48) participated in a cross-sectional study and completed the DIDS and the Youth Self-Report of behavior problems. The Confirmatory Factor Analysis supported the six-factor model of the DIDS, echoing past studies showing the original 5th factor (Exploration in Depth) being divided into Exploration in Depth and Reconsidering the Commitment. The invariance testing showed comparable measurement properties of the DIDS across males and females (strict measurement invariance). Further, behavior problems were associated positively with Ruminative Exploration and negatively with Commitment Making, Identification with Commitments, Exploration in Depth, and Reconsideration of Commitments, whereas the opposite was true for academic performance. A six-factor DIDS was shown to be a valid and reliable measure for the assessment of identity development dimensions among Iranian adolescents. Future studies in the Iranian context evaluating the identity clusters derived from identity dimensions and their gender differences are warranted.     

Multivariate normal mean-variance mixture distribution based on Lindley distribution

This article introduces a new asymmetric distribution constructed by assuming the multivariate normal mean-variance mixture model. Called normal mean-variance mixture of the Lindley distribution, we derive some mathematical properties of the new distribution. Also, a feasible maximum likelihood estimation procedure using the EM algorithm and the asymptotic standard errors of parameter estimates are developed. The performance of the proposed distribution is illustrated by means of real datasets and simulation analysis.     

Mixtures of general location model with factor analyzer covariance structure for clustering mixed type data

Cluster analysis is one of the most widely used method in statistical analyses, in which homogeneous subgroups are identified in a heterogeneous population. Due to the existence of the continuous and discrete mixed data in many applications, so far, some ordinary clustering methods such as, hierarchical methods, k-means and model-based methods have been extended for analysis of mixed data. However, in the available model-based clustering methods, by increasing the number of continuous variables, the number of parameters increases and identifying as well as fitting an appropriate model may be difficult. In this paper, to reduce the number of the parameters, for the model-based clustering mixed data of continuous (normal) and nominal data, a set of parsimonious models is introduced. Models in this set are extended, using the general location model approach, for modeling distribution of mixed variables and applying factor analyzer structure for covariance matrices. The ECM algorithm is used for estimating the parameters of these models. In order to show the performance of the proposed models for clustering, results from some simulation studies and analyzing two real data sets are presented.     

Perceived Environmental Response Mechanism in Tehran Public Spaces

Social Indicators Research - Perception of environmental quality, figured out as a feeling of a space that extend beyond a visual perceptual quality that is usually assumed; it is a complex...     

On the Qualities of a Teacher and a Student: An Eastern perspective based on Buddhism,Vedanta and Sufism

This essay looks at the requirements and qualities of a student and a teacher as seen from Eastern traditions such as Vedanta, Zen Buddhism and Sufism. The objective is to show or to propose that the same qualities are also needed in our present-day education system, no matter what the subject of study is. Though the emphasis is on these three particular systems, it is understood that one can find the same or similar qualities in other spiritual traditions. At the end of the essay, a heat transfer model is developed whereby the different aspects of an "ideal" teacher, sometimes also referred to as the real teacher, or the true teacher, can be obtained from such a model.     

A doubly robust goodness-of-fit test in general linear models with missing covariates

In this article, we utilize a form of general linear model where missing data occurred randomly on the covariates. We propose a test function based on the doubly robust method to investigate goodness of fit of the model. For this aim, kernel method is used to estimate unknown functions under estimating equation method. Doubly robustness and asymptotic properties of the test function are obtained under local and alternative hypotheses. Furthermore, we investigate the power of the proposed test function by means of some simulation studies and finally we apply this method on analyzing a real dataset.     

The impact of acculturation identification and acculturative stress on creativity among Iranian immigrants living in Malaysia

The authors investigate how patterns of heritage and mainstream cultural identification and acculturative stress may explain how Iranians living in Malaysia demonstrate enhanced creativity in creative achievements and creative problem-solving. The sample included 328 Iranian students who were recruited using a cluster sampling method. The results reveal that acculturative strategies (biculturalism, bicultural integration, or bicultural marginalisation) are associated with enhanced creativity. Specifically, strategies that involve disengaging from cultural practices, also referred to as marginalisation, are associated with creative achievements and finding creative solutions to problems. Moreover, heritage cultural identification mediated the relationship between culture shock and creative solution. That is, students who experienced culture shock in the mainstream culture relied on their cultural heritage knowledge and showed decline in their ability to solve a problem creatively. The findings illuminate how creative accomplishment and enhanced creativity potential may be linked to acculturation strategies.     

A new four-parameter lifetime distribution

Generalizing lifetime distributions is always precious for applied statisticians. In this paper, we introduce a new four-parameter generalization of the exponentiated power Lindley (EPL) distribution, called the exponentiated power Lindley geometric (EPLG) distribution, obtained by compounding EPL and geometric distributions. The new distribution arises in a latent complementary risks scenario, in which the lifetime associated with a particular risk is not observable; rather, we observe only the maximum lifetime value among all risks. The distribution exhibits decreasing, increasing, unimodal and bathtub-shaped hazard rate functions, depending on its parameters. It contains several lifetime distributions as particular cases: EPL, new generalized Lindley, generalized Lindley, power Lindley and Lindley geometric distributions. We derive several properties of the new distribution such as closed-form expressions for the density, cumulative distribution function, survival function, hazard rate function, the rth raw moment, and also the moments of order statistics. Moreover, we discuss maximum likelihood estimation and provide formulas for the elements of the Fisher information matrix. Simulation studies are also provided. Finally, two real data applications are given for showing the flexibility and potentiality of the new distribution.