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2757 items in total found

Working Papers | 2013

Market-Driving Behaviors: A Framework for Developing Theory and Practice

Arvind Sahay

Whereas marketing scholars have explored firms' market-driven behaviors, relatively limited attention has focused on firms' market-driving behaviors. Early writings on the subject suggest that market-driving behaviors serve as an important complement to market-driven behaviors. The purpose of this paper is to develop a framework for studying market-driving behaviors and their antecedent conditions. We develop a taxonomy for classifying the different ways in which a firm can drive markets, and delineate the major classes of antecedent conditions under which market-driving behaviors are likely to be observed. An illustrative set of propositions is developed in an effort directed at building theory on the subject. Our framework offers managers a way to structure their strategic thinking in actionable terms. Additionally, the framework offers a platform for further developing theory about market-driving behaviors.

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Working Papers | 2013

Modelling and Analysis of Multivariate Ordinal Categorical Data in Longitudinal Set up

Atanu Biswas and Apratim Guha

In recent years, there has been a tremendous continuing attention to-
wards the modelling and analysis of longitudinal data, although not much
attention is paid to the ordinal categorical data. The problem becomes
more complicated if the observation at every longitudinal time point is
multivariate, and every component of the response vector is ordinal categorical. We develop urn model-type joint probability models with different
correlation structures when the data are of a longitudinal bivariate ordinal
nature, and discuss the methods of their estimation. Some examples which
motivate us to model and analyse such kind of data are also discussed.

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Working Papers | 2013

Modelling and coherent forecasting of zero-inflated time series count data

Raju Maiti, Atanu Biswas, Apratim Guha, and Huat Ong Seng

In this article, a new kind of stationary zero-inflated Pegrams operator based integer-valued time series process of order p with Poisson marginal or ZIPPAR(p) is constructed for modelling a count time series consisting a large number of zeros compared to standard Poisson time series processes. Estimates of the model parameters are studied using three methods, namely Yule-Walker, conditional least squares and maximum likelihood estimation. Also h-step ahead coherent forecasting distributions of the proposed process for p = 1; 2 are derived. Real data set is used to examine and illustrate the proposed model with some simulation studies.

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Working Papers | 2013

On Estimation of Number of Species and Biodiversity

Atanu Biswas and Apratim Guha

Suppose S is the unknown number of species in a community, and the sample consists of m distinct species, fj species are represented j times in the sample, j = 1; 2; ... ; k. Let f0 be the number of missing species in the sample. Several existing approaches are available for estimating f0 (and hence S), and also the measure of biological diversity given by Shannons index of diversity, denoted by H. The standard approach, although derived from elegant distribution theory, uses some sort of approximation, and essentially ignores all the species in the sample with counts two or more. The present paper proposes an alternative estimate of f0, and hence of H, using all the observed counts f1; f2; ; fk. The performance of the proposed estimates are studied and compared with the existing competitors through simulations. Some real data sets are used for illustration.

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Working Papers | 2013

Some Auto-power Divergence Measures for Stationary Time Series of Categorical Data

Atanu Biswas, Maria del Carmen Pardo, and Apratim Guha

For stationary time series of nominal categorical data or ordinal categorical data (with arbitrary ordered numberings of the categories), autocorrelation does not make much sense. Biswas and Guha (2009) used mutual information as a measure of association and introduced the concept of auto-mutual information in this context. In this present paper we generalise to auto-power divergence measures for this purpose and study some special cases. Theoretical properties and simulation results are given along with an illustrative real data example.

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Working Papers | 2013

A Test for the Two-Sample Problem using Mutual Information

Apratim Guha and Tom Chothia

For two independently drawn samples from continuous distributions,
a statistical test based on the mutual information statistic is proposed
for the null hypothesis that both the samples originate from the same
population. Asymptotic properties of the test statistic under the null
hypothesis of equality is developed. It is demonstrated through simulation
that this test is more powerful than the commonly used nonparametric
tests in many situations. As an application we discuss the information
leak of e-passports. Using the mutual information based test, we detect
information leak in a situation where other non-parametric tests fail.

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Working Papers | 2013

Auto-Havra Charvat entropic measures for stationary time series of categorical data

Atanu Biswas, Maria del Carmen Pardo, and Apratim Guha

For stationary time series of nominal categorical data or ordinal categorical data (with arbitrary ordered numberings of the categories), autocorrelation does not make much sense. One can alternatively think of
using some entropic measures, of which a measure introduced by Havrda and Charvat (1967) could be particularly useful. We discuss some theoretical properties of measures from this class in the context of categorical
time series and look at specific examples. Theoretical properties and simulation results are given along with an illustrative real data example.

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Working Papers | 2013

Identifying defective valves in a blowout preventer valve network

Diptesh Ghosh

Blowouts are nancially damaging for drilling companies and are ecological hazards. Hence
blowout prevention equipment is critical infrastructure for drilling companies. Blowout preventer
valves are important components of blowout prevention equipments and need to be checked
regularly. However, since these valves are often physically inaccessible, they are checked in
batches called test sets. In this paper we present an exact method to check the functional status
of all blowout preventer valves using a minimum number of test sets. We also present a heuristic
method to identify malfunctioning valves if they exist. We illustrate both methods using a real
world example.

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Working Papers | 2013

Strategies To Improve Urban Water Delivery In West Bengal, India: An Analysis Of Water Institutions And Benchmarking Of Water Delivery Organizations

Tirthankar Nag and Amit Garg

The study examines the status of urban water delivery in India through a case study of the state of West Bengal in India. The state has been selected as a unit of study to bring out the regional variances that are not captured at a more aggregate or country level study. The study focuses on various types of urban local bodies in the state, the organizational and institutional structure for water delivery and issues around them. The study also benchmarks various urban local bodies for their water service delivery through data envelopment analysis. The study finds that in the current state of fragmented institutions and shared responsibilities between various water organizations, there needs to be a focused policy guideline for integrated development of the water sector in the state. The study also identifies certain categories of urban local bodies, for which there are further scope for efficiency improvement.

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Working Papers | 2013

SB-robustness of Performance Measures of Control Chart

A. K. Laha and Pravida Raja

Control charts play a very important role in the control of manufacturing processes. In this paper we consider the commonly used performance measures for control charts and study their SB-robustness. It is shown that the False Alarm Probability, Average Sample Number (ASN) when the process is in-control, No-Signal Probability and ASN when the process is out-of-control are all SB-robust at the family of all normal distributions with bounded mean and standard deviation. It is also shown that these performance measures are not SB-robust at the larger family of normal distributions with unbounded mean and standard deviation.

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