An alternative estimator for multiple characteristics in PPS sampling

The problem considered relates to large-scale sample surveys. A new estimator of population total for the characteristics that are poorly correlated with the selection probabilities has been developed for the PPSWR sampling scheme. The relative efficiency of the proposed estimator has been studied under a super-population model. A numerical investigation into the performance of the estimator has also been made.     

Managing Demand Uncertainty through Core Acquisition in Remanufacturing

We discuss the optimal raw material acquisition strategy for a third party remanufacturer (3PR). We specifically investigate whether a 3PR should acquire used products or cores in bulk with uncertain quality levels, or in sorted grades with known quality levels; and whether to acquire and remanufacture cores before the demand is realized (planned acquisition), or after the demand is realized (reactive acquisition), or on both occasions (sequential acquisition). When only sorted cores are acquired, we find that, (i) it is optimal to acquire cores in multiple grades to balance acquisition and remanufacturing costs; (ii) if reactive acquisition is possible, it reduces the assortment size (number of grades in which cores are acquired) and the total inventory acquired in the planned acquisition; and (iii) the optimal portfolio of grades to acquire and the optimal acquisition and remanufacturing quantities of these grades can be determined analytically. When bulk cores are acquired in addition to sorted cores, the property of reduction in assortment size of the planned acquisition is preserved. We also show that the 3PR should acquire only a fraction of the demand in planned acquisition, and leave the rest for reactive acquisition. This fraction changes during the lifecycle of a remanufactured product. Using a combination of empirical and realistic data from a smartphone remanufacturer we show that sequential acquisition increases expected profit by up to 8% and 27% over only planned and only reactive acquisitions respectively, and reduces the inventory acquired by up to 21% over only planned acquisition.     

The Pune Slum Census: creating a socio-economic and spatial information base on a GIS for integrated and inclusive city development

Urban planning systems rarely include the poor. Cities are growing and so is the urban population. Pune is a large city in Western Maharashtra. According to the National Census, 2001, the population of the Pune urban agglomeration is 3.5 million and it is (in some estimates) to reach nearly 6 million by 2021.¹ Out of this, the city of Pune has a 2.5 million people living in it. Forty percent and above of the population live in slums. One of the biggest shortfalls of Pune's urban planning is that it still fails to include the poor in mainstream policies. The reason is that the poor are hardly known about, in fact, even government authorities are unaware about how many poor people there are in Pune. This attitude, and the fact that Shelter Associates (SA) work is closely connected with the poor regarding basic services and housing, started the development of a slum database by SA. Finally, the Pune Municipal Corporation asked us to make a complete census of the slum dwellers in the year 2000. That gave rise to a detailed survey of Pune's slum dwellers, to become, amongst other things, the first ever spatial and socio-economic census processed and analysed on a geographical information system (GIS). The Pune Slum Census has built upon this experience and expanded the communities’ information base, and has created a methodology which the city can use to work on detailed urban planning using a GIS and with the slum database as the base. This article focuses on the Pune Slum Census in progress.     

An Application of EM Algorithm to a Change-Point Problem

We consider the problem of change-point in a classical framework while assuming a probability distribution for the change-point. An EM algorithm is proposed to estimate the distribution of the change-point. A change-point model for multiple profiles is also proposed, and EM algorithm is presented to estimate the model. Two examples of Illinois traffic data and Dow Jones Industrial Averages are used to demonstrate the proposed methods.     

Bayes Prediction for a Heteroscedastic Regression Superpopulation Model Using Balanced Loss Function

We consider Prais–Houthakker heteroscedastic normal regression model having variance of the dependent variable same as square of its expectation. Bayes predictors for the regression coefficient and the mean of a finite population are derived using Zellner's balanced loss function. Bayes predictive expected losses are obtained and compared with those of classical predictors and Bayes predictors under squared error loss function to examine their loss robustness.     

On the mixtures of Weibull and Pareto (IV) distribution: An alternative to Pareto distribution

Finite mixture models have provided a reasonable tool to model various types of observed phenomena, specially those which are random in nature. In this article, a finite mixture of Weibull and Pareto (IV) distribution is considered and studied. Some structural properties of the resulting model are discussed including estimation of the model parameters via expectation maximization (EM) algorithm. A real-life data application exhibits the fact that in certain situations, this mixture model might be a better alternative than the rival popular models.     

Bayesian decision theoretic approach to hypothesis problems with skewed alternatives

Many hypothesis problems in practice require the selection of the left side or the right side alternative when the null is rejected. For parametric models, this problem can be stated as _H0:θ=_θ0$H_0:\theta ={\theta }_0$vs.  _H−:θ<_θ0$H_{-}:\theta <{\theta }_0$ or _H+:θ>_θ0$H_{+}:\theta >{\theta }_0$. Frequentists use Type-III error (directional error) to develop statistical methodologies. This approach and other approaches considered in the literature do not take into account the situations where the selection of one side may be more important or when one side may be more probable than the other. This problem can be tackled by specifying a loss function and/or by specifying a hierarchical prior structure with allowing the skewness in the alternatives. Based on this, we develop a Bayesian decision theoretic methodology and show that the resulted Bayes rule perform better in the side of the alternatives which is more probable. The methodology can be also used in a frequentist's framework when it is desired to discover an alternative that is more important. We also consider the multiple hypotheses problem and develop new false discovery rates for the selection of the left and the right sides of alternatives. These discovery rates would be useful in the situations when one side of the alternatives are more important or more probable than the other.     

Rethinking non-traditional resistance at work: The case of the Indian Diaspora in Mauritius

Resistance at work can take many forms and be theorised in multiple ways. In this paper, I use postcolonial theorist Homi Bhabha's concepts of mimicry, ambivalence and hybridity to explore non-traditional forms of resistance among Indo-Mauritians working in the hotel industry. I employ a two-stage qualitative research approach by conducting focus groups in eight hotels in Mauritius followed by focused ethnography with 20 Indo-Mauritians. The findings reveal that the Indian diasporic community is actively engaging with its past (India) through the materiality of its home, its sacred space and its use of Bhojpuri to communicate. By unfolding and maintaining its difference, it is constantly demarcating its personal space from that of the Other. As this behaviour extends to the workplace, salient forms of non-traditional resistance surface in rural regions.