The topology aware file distribution problem

We present theoretical results for large-file distribution on general networks of known topology (known link bandwidths and router locations). We show that the problem of distributing a file in minimum time is NP-hard in this model, and we give an O(logn) approximation algorithm, where n is the number of workstations that require the file. We also characterize our method as optimal amongst the class of “no-link-sharing” algorithms.     

Risk Pooling Advantages of Manufacturing Network Configuration

The decision of a firm to set up a plant network is influenced by a number of factors, including demand fluctuations across its portfolio of products, logistics costs, and service level requirements. Product plant networks offer the benefits of consolidated production and reduced transshipment costs; on the other hand, process plant networks allow intensive dedication to process expertise and economies of scale. In this paper, we show that, aside from these benefits, process plant networks offer significant risk pooling advantages under a wide range of conditions. We analytically demonstrate that, even without accounting for economies of scale advantages, firms may prefer the process plant network configuration due to the risk pooling benefits offered.     

Investing in a Shared Supplier in a Competitive Market: Stochastic Capacity Case

When firms invest in a shared supplier, one key concern is whether the invested capacity will be used for a competitor. In practice, this concern is addressed by restricting the use of the capacity. We consider what happens when two competing firms invest in a shared supplier. We consider two scenarios that differ in how capacity is used: exclusive capacity and first‐priority capacity. We model firms' investment and production decisions, and analyze the equilibrium outcomes in terms of the number of investing firms and capacity levels for each scenario; realized capacity is a stochastic function of investment levels. We also identify conditions under which the spillover effect occurs, where one firm taps into the other firm's invested capacity. Although the spillover supposedly intensifies competition, it actually discourages firms' investment. We also characterize the firms' and supplier's preference about the capacity type. While the non‐investing firm always prefers spillovers from the first‐priority capacity, the investing firm does not always want to shut off the other firm's access to its leftover capacity, especially when allowing spillover induces the other firm not to invest. The supplier's preference depends on the trade‐off between over‐investment and flexibility.     

New algorithms for online rectangle filling with <Emphasis Type="BoldItalic">k</Emphasis>-lookahead

We study the online rectangle filling problem which arises in channel aware scheduling of wireless networks, and present deterministic and randomized results for algorithms that are allowed a k-lookahead for k≥2. Our main result is a deterministic min {1.848,1+2/(k−1)}-competitive online algorithm. This is the first algorithm for this problem with a competitive ratio approaching 1 as k approaches +∞. The previous best-known solution for this problem has a competitive ratio of 2 for any k≥2. We also present a randomized online algorithm with a competitive ratio of 1+1/(k+1). Our final result is a closely matching lower bound (also proved in this paper) of $1+1/(\sqrt{k+2}+\sqrt{k+1})^{2}>1+1/(4(k+2))$1+1/(\sqrt{k+2}+\sqrt{k+1})^{2}>1+1/(4(k+2)) on the competitive ratio of any randomized online algorithm against an oblivious adversary. These are the first known results for randomized algorithms for this problem.     

Racialized Incorporation: The Effects of Race and Generational Status on Self‐Employment and Industry‐Sector Prestige in the United States

This study examines how race and generational status shape self‐employment propensities and industry‐sector prestige among the self‐employed in the U.S. It draws on theories of assimilation, racialization, and a combined framework, racialized incorporation, to guide the analysis and interpret the results. It uses data from the U.S. March Current Population Survey (2000–2010) offering the first nationally representative examination of second‐generation self‐employment in the U.S. This study investigates three questions. First, do the odds of being self‐employed decline in the second and third generations? Second, do generational patterns in self‐employment propensities vary by race? And finally, do race and generational status affect the odds of being self‐employed in low‐, medium‐, and high‐prestige industry sectors? Results offer some support for the assimilation perspective: Immigrants are generally more likely than third‐generation groups to be self‐employed with the exception of Asians, where second‐generation Asians have the greatest odds of being self‐employed. However, results also reveal that generational patterns in self‐employment propensities vary by race and industry‐sector prestige. Accordingly, first‐ and second‐generation whites have the greatest odds of being self‐employed (across all levels of industry‐sector prestige), and third‐generation whites are more likely than all generations of blacks and Hispanics to be engaged in high‐prestige self‐employment. These findings suggest that immigrants, their offspring, and native‐born groups undergo a racialized incorporation in which self‐employment is organized along hierarchical and racial lines associated with uneven levels of prestige.     

Exploring the influence of pre-training factors on training effectiveness-moderating role of trainees’ reaction: a study in the public sector in India

Organizations invest in training initiative with an objective to improve the performance of its employees and ultimately organizational performance. However, training literature highlights the gap between the learning and the transfer of learning at the workplace. Thus, there is a need to have a deeper understanding of those variables which contributes to training transfer/effectiveness. This study is an attempt to understand those organizational factors that can help in improving training effectiveness. Data was collected at three different points of time (before training, immediately at the end of training and after some time of training) to determine the antecedents of motivation to learn and the training effectiveness. Findings of the study reveal that motivation to learn mediates the relationship between the predictor variables – training needs analysis, training information and type of training, and the resultant variable training effectiveness. Also, trainees’ reaction towards training was found to moderate the relationship between trainees’ motivation to learn and training effectiveness. The study reinforces the significance of organizational factors in ensuring motivation to learn and training effectiveness. Theoretical and managerial implications are discussed in the paper.     

An autopsy-based evaluation of deaths of homeless unknown persons (HUPs)

Background: India is a significant host to homeless unknown persons (HUPs) and subsequently to their untimely deaths due to various reasons. The autopsy-based evaluation has been always important in knowing the exact reasons behind it. Objective: To know about the epidemiological mortality profile such as magnitude, cause and manner of death, seasonality, and year-wise distribution of their untimely and unattended deaths. Materials and Methods: A retrospective autopsy-based evaluation of unnatural deaths among HUPs was done at LHMC, New Delhi for a total duration of 5 years (January 2006 to December 2010). Results: Out of 749 cases in the study group in this duration, 536 deaths have been caused due to some natural events and 213 due to some unnatural events. Among the natural deaths, the pulmonary pathology did contribute for 509 cases. Conclusion: The study population is a vulnerable segment of the society which often suffers the extreme adversity of natural and unnatural events in the form of their deaths. It is a significant host to the pulmonary infections that often spread to the other segments of the society at the point of contact. Thereby it deserves an urgent public health intervention and a policy response for the same for the well-being of HUPs and the general public at large.     

An Experimental Analysis of Capacity-Sensitive Setup Parameters for MRP Lot Sizing

Most material requirements planning (MRP) systems apply standard costing (absorption costing) approaches to define setup costs that are used as fixed (time invariant) setup parameters in single-level lot-sizing methods. This paper presents a computationally simple approach for estimating more appropriate setup parameters based on estimates of work-center shadow prices. These setup parameters then are used in traditional single-level MRP lot-sizing procedures. The shadow price of capacity at each work center is calculated as the increase in the overall inventory carrying cost for each additional hour of capacity lost to setups. The opportunity cost of a setup for an order subsequently is determined based on the routing information for each order and is used by traditional MRP lot-sizing procedures to calculate lot sizes. A simulation experiment compares the performance period order quantity lot sizing with capacity-sensitive setup parameters with the fixed accounting-based setup parameters. The simulation replicates the planning and control functions of a typical MRP system. The results of the experiment show that capacity-sensitive setup parameters can make significant reductions in both carrying cost and lateness and can achieve many of the benefits of optimized production technology in the context of an MRP system.