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1.
The special issue focuses on the theory and evidence linking the use of Big Data related technologies by businesses with their performance. Here we connect the papers accepted for the special issue to the overarching theme of Big Data as an emerging concept within the business management literature. We present two prominent case studies examining the use Big Data technologies on performance and strategy, followed by a discussion on how themes around Big Data and Performance may be examined from a theoretical perspective. Finally, based on a synthesis of papers in the current issue, we discuss the emerging issues and trends within the academic literature, relevant for future research. 相似文献
2.
Predictive Inference for Big,Spatial, Non‐Gaussian Data: MODIS Cloud Data and its Change‐of‐Support 下载免费PDF全文
Aritra Sengupta Noel Cressie Brian H. Kahn Richard Frey 《Australian & New Zealand Journal of Statistics》2016,58(1):15-45
Remote sensing of the earth with satellites yields datasets that can be massive in size, nonstationary in space, and non‐Gaussian in distribution. To overcome computational challenges, we use the reduced‐rank spatial random effects (SRE) model in a statistical analysis of cloud‐mask data from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on board NASA's Terra satellite. Parameterisations of cloud processes are the biggest source of uncertainty and sensitivity in different climate models’ future projections of Earth's climate. An accurate quantification of the spatial distribution of clouds, as well as a rigorously estimated pixel‐scale clear‐sky‐probability process, is needed to establish reliable estimates of cloud‐distributional changes and trends caused by climate change. Here we give a hierarchical spatial‐statistical modelling approach for a very large spatial dataset of 2.75 million pixels, corresponding to a granule of MODIS cloud‐mask data, and we use spatial change‐of‐Support relationships to estimate cloud fraction at coarser resolutions. Our model is non‐Gaussian; it postulates a hidden process for the clear‐sky probability that makes use of the SRE model, EM‐estimation, and optimal (empirical Bayes) spatial prediction of the clear‐sky‐probability process. Measures of prediction uncertainty are also given. 相似文献
3.
Alternative decision rules for aggregate production scheduling are specified here under chance-constrained sales and compared with the HMMS model. These rules are evaluated for their performance on the basis of simulated data on sales and it is found that the linear decision rules of the HMMS model can be considerably improved. 相似文献
4.
Manimay Sengupta 《Journal of Economic Inequality》2009,7(3):273-294
We propose a framework in which the welfare bases of various unemployment measures available in the literature can be analyzed
and a decomposition of these measures can be made into aggregate unemployment and the concentration of its distribution. A
set of axioms for an unemployment measure is then introduced, which relate to the sensitivity of an unemployment measure to
the inequality in the distribution of the unemployment. An unemployment measure is derived on the basis of these axioms that
captures the distributional considerations in the measurement of unemployment.
相似文献
5.
Sedigheh Mirzaei Salehabadi Debasis Sengupta Rituparna Das 《Scandinavian Journal of Statistics》2015,42(1):290-305
Menarche, the onset of menstruation, is an important maturational event of female childhood. Most of the studies of age at menarche make use of dichotomous (status quo) data. More information can be harnessed from recall data, but such data are often censored in a informative way. We show that the usual maximum likelihood estimator based on interval censored data, which ignores the informative nature of censoring, can be biased and inconsistent. We propose a parametric estimator of the menarcheal age distribution on the basis of a realistic model of the recall phenomenon. We identify the additional information contained in the recall data and demonstrate theoretically as well as through simulations the advantage of the maximum likelihood estimator based on recall data over that based on status quo data. 相似文献
6.
S. Sengupta 《统计学通讯:理论与方法》2013,42(19):5745-5750
ABSTRACTLet P be the proportion of individuals in a finite population possessing a sensitive attribute. We consider the problem of unbiased estimation of (i) the variance of a linear unbiased estimator of P and (ii) the population variance P (1—P) for a given probability sampling design under Warner's (1965) randomized response (RR) plan when independent responses are obtained from each sampled individual as many times as he/she is selected in the sample and prove the admissibility of a quadratic unbiased estimator for each. 相似文献
7.
A sequence of independent lifetimes X 1,…, X m , X m+1,…, X n were observed from inverse Weibull distribution with mean stress θ1 and reliability R 1(t 0) at time t 0 but later it was found that there was a change in the system at some point of time m and it is reflected in the sequence after X m by change in mean stress θ1 and in reliability R 2(t 0) at time t 0. The Bayes estimators of m, R 1(t 0) and R 2(t 0) are derived when a poor and a more detailed prior information is introduced into the inferential procedure. The effects of correct and wrong prior information on the Bayes estimators are studied. 相似文献
8.
Two types of estimates of process level, namely repeated median estimates (Siegel, 1982) and full online estimates (Gather et al., 2006) based on repeated median filters, are used to develop control charts. The distributional properties of the estimates are studied using simulation and these are found to closely follow normal distribution. The repeated median being robust against outliers with asymptotically 50% breakdown value and having small standard deviation is found to be useful as a basis for monitoring process averages. The control charts using repeated median estimates have been recommended for general use. 相似文献
9.
Anirban Sengupta 《Children and youth services review》2011,33(2):284-290
Media reports on incidences of abuse on the internet, particularly among teenagers, are growing at an alarming rate causing much concern among parents of teenagers and prompting legislations aimed at regulating internet use among teenagers. Social networking sites (SNS) have been criticized for serving as a breeding ground for cyber-bullying and harassment by strangers. However, there is a lack of serious research studies that explicitly identify factors that make teenagers prone to internet abuse, and study whether it is SNS that is causing this recent rise in online abuse or is it something else. This study attempts to identify the key factors associated with cyber-bullying and online harassment of teenagers in the United States using the 2006 round of Pew Internet™ American Life Survey that is uniquely suited for this study. Results fail to corroborate the claim that having social networking site memberships is a strong predictor of online abuse of teenagers. Instead this study finds that demographic and behavioral characteristics of teenagers are stronger predictors of online abuse. 相似文献
10.
In this paper, we have considered the issues concerning dynamic changes in HDI and its various components from a relative standpoint. The analysis of HDI mobility should entail directional movement introduced by Fields (in Distribution and development: a new look at the developing world. MIT Press, Cambridge, 2001). However, Fields’ analysis was in the space of absolute values. Here, we will try to extend this exercise to the positional mobility index by considering the question of improvement and deterioration in relative positions. This requires the concept of partial mobility where mobility is judged from the viewpoint of a particular group. We then try to introduce directional changes in partial mobility through axiomatic framework. Finally, we provide an illustrative example from the Indian data. 相似文献