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Let X be a random variable and X(w) be a weighted random variable corresponding to X. In this paper, we intend to characterize the Pearson system of distributions by a relationship between reliability measures of X and X(w), for some weight function w>0.
Journal of Statistical Planning and Inference (03783758)81(2)pp. 201-207
Many characterization results of the bivariate exponential distribution and the bivariate geometric distribution have been proved in the literature. Recently Nair and Nair (1988b, Ann. Inst. Statist. Math. 40 (2), 267-271) obtained a characterization result of the Gumbel bivariate exponential distribution and a bivariate geometric distribution based on truncated moments. In this note, we extend the results of to obtain a general result, characterizing these two bivariate distributions based on the truncated expectation of a function h, satisfying some mild conditions.
In this paper, we characterize some multivariate distributions based on a relationship between the multivariate hazard rate, as defined by Johnson and Kotz (1975) and Marshall (1975), and the multivariate mean residual life as defined by Arnold and Zahedi (1988). The results are extensions of the results obtained earlier by Roy (1989, 1990) and Ma (1996, 1997).
Statistics and Probability Letters (01677152)49(3)pp. 263-269
A direct approach to measure uncertainty in the residual life time distribution has been initiated by Ebrahimi (1996, Sankhya Ser. A 58, 48-57) and explored further by Ebrahimi and Pellerey (1995) and Ebrahimi and Kirmani (1996). In this paper, some new properties of the proposed measure in connection to order statistics and record values are derived. The generalized Pareto distribution has been widely used in the literature. We have also given several characterizations of this distribution in terms of the proposed measure.
Asadi, M., Ebrahimi, N., Hamedani, G., Soofi, E.S.
Journal of Applied Probability (00219002)41(2)pp. 379-390
A formal approach to produce a model for the data-generating distribution based on partial knowledge is the well-known maximum entropy method. In this approach, partial knowledge about the data-generating distribution is formulated in terms of some information constraints and the model is obtained by maximizing the Shannon entropy under these constraints. Frequently, in reliability analysis the problem of interest is the lifetime beyond an age t. In such cases, the distribution of interest for computing uncertainty and information is the residual distribution. The information functions involving a residual life distribution depend on t, and hence are dynamic. The maximum dynamic entropy (MDE) model is the distribution with the density that maximizes the dynamic entropy for all t. We provide a result that relates the orderings of dynamic entropy and the hazard function for distributions with monotone densities. Applications include dynamic entropy ordering within some parametric families of distributions, orderings of distributions of lifetimes of systems and their components connected in series and parallel, record values, and formulation of constraints for the MDE model in terms of the evolution paths of the hazard function and mean residual lifetime function. In particular, we identify classes of distributions in which some well-known distributions, including the mixture of two exponential distributions and the mixture of two Pareto distributions, are the MDE models.
Communications in Statistics - Theory and Methods (1532415X)36(7)pp. 1333-1341
In recent years, several attempts have been made to characterize the generalized Pareto distributions (GPD) based on the properties of order statistics and record values. In the present article, we give some characterization results on GPD based on order statistics and generalized order statistics. Some characterizations of uniform distribution based on expectation of some functions of order statistics are also given.
Communications in Statistics - Theory and Methods (1532415X)37(9)pp. 1347-1352
In recent years, several attempts have been made to characterize the generalized Pareto distribution (GPD) based on the properties of order statistics and record values. In the present article, we give a characterization result on GPD based on the spacing of generalized order statistics.
European Journal of Social Sciences (discontinued) (14502267)15(4)pp. 599-610
Management is increasingly transforming to Knowledge management. This means that we manage Knowledge of people not themselves, and leadership means providing good condition for producing valued Knowledge by human and accomplishing this by the way that persuade people to accountability. Contemporary clear sighted says that Knowledge is considered as the main source of competitive advantage, and for the organizations to achieve such advantage. This paper seeks for Amount of Paying Attention to Knowledge Management in Automobile Industry of Iran. The results indicate that there has been attention to creating, maintaining, and disseminating and applying knowledge management in Automobile Industry Findings of data analysis show that in Iran's automobile industry, attention paid to creating, maintaining, sharing, applying and generally knowledge management has been lower than the intended amount.
Asl, N.S., Dost, H.N., Kalantery, M., Talebi, H., Khosravi, A.
Koomesh (23453699)11(4)pp. 294-302
Introduction: Essential hypertension is one of the most important factors on quality of life and third casual of death in the world. The purpose of the present study was to determine the effect of cognitive behavioral therapy and drug therapy on improvement of quality of life in the patients with essential hypertension. Materials and Methods: This clinical trial was performed in Heart center of Medical Uuniversity of Isfahan (Iran) between April 2007 and April 2008. 40 Patients with essential hypertension were selected randomly and assigned into 2 groups: experimental group that received cognitive behavioral therapy and control group with drug therapy. All of the patients completed the quality of life and a demographic questionnaire before start of interventions as pre test. The post test was completed after the end of intervention and follow up completed after 4 month later. Results: Findings showed that cognitive behavioral therapy was more effective than drug therapy on improvement of quality of life in the patients with essential hypertension in post test and follow up. Conclusion: Cognitive behavioral therapy was effective on improvement of quality of life in the patients with essential hypertension. According to findings of this work, we suggest that team work approach consist of psychologists and heart professional can be useful for treatment of quality of life in the patients with essential hypertension.
In this paper some models are applied to analyze insomnia data. Insomnia is a sleep disorder in which the patient does not get enough or satisfactory sleep and investigating the use of hypnotic drug for its cure is so important. For studying the effect of drugs on insomnia, it is useful to observe the response of interest (cured or not cured) for each subject repeatedly at several times. So, a longitudinal study of repeated binary responses along with a treatment variable (with two levels hypnotic or placebo) are used for some individuals on two times. A very important feature of the data is that the correlation between the two longitudinal responses depends on the level of hypnotic drug. This is, firstly, shown by an exploratory data analysis. Then, as an option, Dale's bivariate model for analyzing longitudinal or repeated measurements of binary responses, considering the effect of treatment on the responses and the correlation structure, is used to find an overall population effect on the responses. As other options, transition and random effect models for analyzing these data are used to investigate, respectively, the reasons for the change of the responses and to find the subject-specific variations. How the interpretation of the results is different with the use of the Dale's model and how one may find out the effect of the drug on the correlation structure by a transition or random effect model are also discussed.
