Fitting bivariate multilevel models to assess long-term changes in body mass index and cigarette smoking

Using data from the National Health interview Survey from 1997 to 2006, we present a multilevel analysis of change in body mass index (BMI) and number of cigarettes smoked per day in the USA. Smoking and obesity are the leading causes of preventable mortality and morbidity in the USA and most parts of the developed world. A two-stage bivariate model of changes in obesity and number of cigarette smoked per day is proposed. At the within subject stage, an individual's BMI status and the number of cigarette smoked per day are jointly modeled as a function of an individual growth trajectory plus a random error. At the between-subject stage, the parameters of the individual growth trajectories are allowed to vary as a function of differences between subjects with respect to demographic and behavioral characteristics and with respect to the four regions of the USA (Northeast, West, South and North central). Our two-stage modeling techniques are more informative than standard regression because they characterize both group-level (nomothetic) and individual-level (idiographic) effects, yielding a more complete understanding of the phenomena under study.     

Sharing Responsibility for Product Recovery Across the Supply Chain

Extended producer responsibility (EPR) programs typically hold the producer—a single actor defined by the regulator—responsible for the environmental impacts of end‐of‐life products. This is despite emphasis on the need to involve all actors in the supply chain in order to best achieve the aims of EPR. In this paper, we examine the economic and environmental implications of product recovery mandates and shared responsibility within a supply chain. We use a two‐echelon model consisting of a supplier and a manufacturer to determine the impacts of product collection and recycling mandates on the incentive to recycle and resulting profits in the integrated and decentralized supply chains. For the decentralized supply chain, we demonstrate how the sharing of responsibility for product recovery between the echelons can improve total supply chain profit and suggest a contract menu that can Pareto‐improve profits. To examine both the economic and environmental performance associated with responsibility sharing, we propose a social welfare construct that includes supply chain profit, consumer surplus, and the externalities associated with virgin material extraction, product consumption, and disposal of nonrecycled products. Using a numerical example, we discuss how responsibility sharing may or may not improve social welfare. The results of this paper are of value to firms either anticipating or subject to product recovery legislation, and to social planners that attempt to balance economic and environmental impacts and ensure fairness of such legislation.     

Remanufacturing and the Component Commonality Decision

Firms often determine whether or not to make components common across products by focusing on the manufacturing and sales of new products only. However, component commonality decisions that ignore remanufacturing can adversely affect the profitability of the firm. In this article we analyze how remanufacturing could reverse the OEM's commonality decision that is based on the manufacturing and sales of new products only. Specifically, we determine the conditions under which the OEM's optimal decision on commonality may be reversed and illustrate how her profit can be significantly higher if remanufacturing is taken into account ex ante. We illustrate the implementation of our model for two products in the Apple iPad family.     

Strategic planning catches on in U.S. retailers

This article examines the strategic planning practices of large American retailers. Most retailers surveyed have engaged in strategic planning, almost one-third have hired employees whose main jobs are strategic planning and over two-thirds use outside consultants. Top management participation is also high, the scope of strategic planning is broad both internally and externally, and several standard strategic planning methods are used. Moreover, in spite of the rapid pace of change in retailing, over half of the retailers use long-range time frames. They recognize the value of strategic planning because almost three-quarters intend to increase their emphasis in this area.     

Selection of logistics service provider: An analytic network process (ANP) approach

This article presents a comprehensive methodology for the selection of a logistic service provider. The proposed methodology consists of two parts: (i) preliminary screening of the available providers, and (ii) analytic network process (ANP)-based final selection. The criteria, which are relevant in the selection of a provider, have been identified and used to construct an ANP model. Thereafter, the application of ANP for the final selection of a provider has been demonstrated through an illustrative example. The results of this example indicate that compatibility between the user and the provider companies is the most important determinant, which influences the final selection process. This approach also enables the decision-makers to better understand the complex relationships of the relevant attributes in the decision-making, which may subsequently improve the reliability of the decision.     

Approximation Algorithms for Certain Network Improvement Problems

We study budget constrained network upgrading problems. Such problems aim at finding optimal strategies for improving a network under some cost measure subject to certain budget constraints. Given an edge weighted graph G = (V, E), in the edge based upgrading model, it is assumed that each edge e of the given network also has an associated function ce (t) that specifies the cost of upgrading the edge by an amount t. A reduction strategy specifies for each edge e the amount by which the length (e) is to be reduced. In the node based upgrading model, a node v can be upgraded at an expense of c(v). Such an upgrade reduces the delay of each edge incident on v. For a given budget B, the goal is to find an improvement strategy such that the total cost of reduction is at most the given budget B and the cost of a subgraph (e.g. minimum spanning tree) under the modified edge lengths is the best over all possible strategies which obey the budget constraint.After providing a brief overview of the models and definitions of the various problems considered, we present several new results on the complexity and approximability of network improvement problems.     

Knowledge management based collaboration moderator services to support SMEs in virtual organizations

Abstract

Collaboration Moderator Services (CMS) are discussed as a Knowledge management service for SMEs operating in a virtual organization (VO). In this research, a CMS supports the pre-creation stage of a VO by quickly identifying potential business opportunities and collaborative partners. Text mining techniques are used to analyze calls for tender documents based on the competencies and areas of interest stored in the shared information about companies in a collaboration pool. A case study of UK-based SMEs demonstrates the application of text mining as a knowledge discovery tool, supporting SMEs at the pre-creation stage of a VO. Results show that text mining can be used to (1) identify possible business opportunities for SMEs in the collaborative network (2) Indicate potential collaborations between pairs of SMEs using link analysis and (3) Raise awareness of business opportunities and possible SME partners for multi-enterprise collaborations using a dimensional matrix.     

Dynastic inequality,mobility and equality of opportunity

One often heard counter to the concern about rising income and wealth inequality is that it is wrong to focus on inequality of outcomes in a “snapshot”. Intergenerational mobility and “equality of opportunity”, so the argument goes, is what matters for normative evaluation. In response to this counter, we ask what pattern of intergenerational mobility leads to lower inequality not between individuals but between the dynasties to which they belong? And how does this pattern in turn relate to commonly held views on what constitutes equality of opportunity? We revive and revisit here our earlier contributions which were in the form of working papers (Kanbur and Stiglitz 1982, 1986) in order to engage with the current debate. Focusing on bistochastic transition matrices in order to hold constant the steady state snapshot income distribution, we develop an explicit partial ordering which ranks matrices on the criterion of inequality between infinitely lived dynasties. A general interpretation of our result is that when comparing two transition matrices, if one matrix is “further away” from the identity matrix then it will lead to lower dynastic inequality. More specifically, the result presents a computational procedure to check if one matrix dominates another on dynastic inequality. We can also assess “equality of opportunity”, defined as identical prospects irrespective of starting position. We find that this is not necessarily the mobility pattern which minimizes dynastic inequality.     

Modelling critical success factors for sustainability initiatives in supply chains in Indian context using Grey-DEMATEL

Sustainability assists organisations to enhance ecological, financial and societal performances of their entire supply chains. The present paper uncovers the Critical Success Factors (CSFs) for effective adoption of sustainability initiatives in the supply chain in Indian context. Fifteen CSFs for the successful adoption of sustainability initiatives were identified and finalised firstly from the literature and followed by expert inputs. A methodology based on Grey-Decision Making Trial and Evaluation Laboratory (DEMATEL) was used to envisage the organisation of complex causal relationships between the recognised CSFs. ‘Government Legalisation’ has been found to be the most influential factor and ‘Community Welfare and Development’ is most easily influenced factor. A multiple case example of three automotive companies operating in India is conducted. To the end, some important policy measures and recommendations are proposed to help practicing managers and government bodies to adopt and effectively manage the concepts of sustainability oriented supply chains in India.