PLANNING FOR TRUCK FLEET SIZE IN THE PRESENCE OF A COMMON-CARRIER OPTION

This paper considers a class of network optimization problems in which certain directed arcs must be covered by a set of cycles. Our study was motivated by a distribution planning problem of a commercial firm that had to make deliveries over several origin-destination pairs (directed arcs) and that could service any demand arc by using a vehicle in its own fleet or by paying a common carrier. The problem is to determine an optimal fleet size and the resulting vehicle routes while satisfying maximum route-time restrictions. We formulate the problem, describe some approximate solution strategies, and discuss important implementation issues.     

Financing Empowerment? How Foreign Aid to Southern Ngos and Social Movements Undermines Grass‐Roots Mobilization

The article examines why many foreign‐funded, resource‐ rich movements in developing countries have been unable to produce the massive mobilization found in other successful social movements with access to fewer resources. While foreign ties have brought substantial benefits to local movements, many such social movements have limited grass‐roots support. The issue of external aid is at the core of an emerging research agenda in the fields of international relations, social movements, and development studies that focuses on the relationship between participatory development, democratization, and the process of transnationalization. Drawing on research work from these different fields, the article argues that by making constituency support irrelevant, internationalization through financial assistance has transformed conflict movements into consensus movements that follow an institutional, resource‐dependent, non‐conflictual strategy with no deep roots in the community. The article specifies the mechanisms by which foreign funding affects grass‐roots mobilization. These arguments are examined with respect to evidence from around the world.     

On Maximum Likelihood Estimation for the Two Parameter Burr XII Distribution

This article considers three related aspects of maximum likelihood estimation of parameters in the two-parameter Burr XII distribution. Specifically, we first provide further clarification to some limiting results in Wingo (1993 Wingo , D. R. ( 1993 ). Maximum likelihood estimation of Burr XII distribution parameters under Type II censoring . Microelectron. Reliab. 33 : 1251 – 1257 .[Crossref], [Web of Science ®] , [Google Scholar]). We then focus on details in a proof of the uniqueness of the maximum likelihood estimators. Finally, we consider using the likelihood approach for data which does not satisfy Wingo's criterion, and show that this results in fitting either a Pareto distribution or an intuitively sensible degenerate distribution to the data. The discussion here is completely general, and not restricted to data obtained under Type II censoring.     

International Funding of NGOs in India: Bringing the State Back In

This article seeks to understand how the Indian state exercises control over transnational ties between foreign and domestic actors by examining the national legislative practices that determine receipt of foreign funds and the data on foreign funding flows to NGOs (a database of more than 18,000 associations). The article shows how legislative practices of democratic states serve to reduce foreign influence. Issue characteristics are also shown to determine state response to externalization, blocking transnational ties in “high politics” areas such as minority claims. Finally, within state imposed restrictions, religious rather than secular organizations remain dominant transnational actors in India. The study contributes evidence to suggest that contrary to the arguments of world polity theory and many transnational social movement scholars, states continue to remain powerful actors limiting transnationalization.

Reversible jump MCMC to identify dropout mechanism in longitudinal data

Existence of missing values is an inseparable part of longitudinal studies in epidemiology, medical and clinical studies. Usually researchers, for simplicity, ignore the missingness mechanism while, ignoring a not at random mechanism may lead to misleading results. In this paper, we use a Bayesian paradigm for fitting selection model of Heckman, which allows the non-ignorable missingness for longitudinal data. Also, we use reversible-jump Markov chain Monte Carlo to allow the model to choose between non-ignorable and ignorable structures for missingness mechanism, and show how the selection can be incorporated. Some simulation studies are performed for illustration of the proposed approach. The approach is also used for analyzing two real data sets.     

Parameter Estimation and Censored Lives

The usual likelihood used to make inferences about parameters of lifetime distributions when lives may be censored consists of the product of probability densities for completed lives and reliabilities for the censored lives. This works well in many situations. We consider two special cases of a model which assumes a Poisson birth process for the items: in one case the usual method works well, but in the other case it does not, and better estimates are found.     

Importance of Components for a System

Which component is most important for a system's survival? We answer this question by ranking the information relationship between a system and its components. The mutual information (M) measures dependence between the operational states of the system and a component for a mission time as well as between their life lengths. This measure ranks each component in terms of its expected utility for predicting the system's survival. We explore some relationships between the ordering of importance of components by M and by Zellner's Maximal Data Information (MDIP) criterion. For many systems the bivariate distribution of the component and system lifetimes does not have a density with respect to the two-dimensional Lebesgue measure. For these systems, M is not defined, so we use a modification of a mutual information index to cover such situations. Our results for ordering dependence are general in terms of binary structures, sum of random variables, and order statistics.     

A series of single array 2m factorial search designs for even m

By means of a search design one is able to search for and estimate a small set of non‐zero elements from the set of higher order factorial interactions in addition to estimating the lower order factorial effects. One may be interested in estimating the general mean and main effects, in addition to searching for and estimating a non‐negligible effect in the set of 2‐ and 3‐factor interactions, assuming 4‐ and higher‐order interactions are all zero. Such a search design is called a ‘main effect plus one plan’ and is denoted by MEP.1. Construction of such a plan, for 2^m factorial experiments, has been considered and developed by several authors and leads to MEP.1 plans for an odd number m of factors. These designs are generally determined by two arrays, one specifying a main effect plan and the other specifying a follow‐up. In this paper we develop the construction of search designs for an even number of factors m, m≠6. The new series of MEP.1 plans is a set of single array designs with a well structured form. Such a structure allows for flexibility in arriving at an appropriate design with optimum properties for search and estimation.