A two-agent single machine scheduling problem with due-window assignment and a common flow-allowance

We study a single-machine scheduling model combining two competing agents and due-date assignment. The basic setting involves two agents who need to process their own sets of jobs, and compete on the use of a common processor. Our goal is to find the joint schedule that minimizes the value of the objective function of one agent, subject to an upper bound on the value of the objective function of the second agent. The scheduling measure considered in this paper is minimum total (earliness, tardiness and due-date) cost, based on common flow allowance, i.e., due-dates are defined as linear functions of the job processing times. We introduce a simple polynomial time solution for this problem (linear in the number of jobs), as well as to its extension to a multi-agent setting. We further extend the model to that of a due-window assignment based on common flow allowance.     

Poetics of place and the transformation of the Russian Jewish American self in Lara Vapnyar’s The Scent of Pine and Yelena Akhtiorskaya’s Panic in a Suitcase

ABSTRACT

In The Scent of Pine and Panic in a Suitcase, Russian Jewish American authors Lara Vapnyar and Yelena Akhtiorskaya explore the interiority of the immigrant self in various stages of the immigrant journey from the former Soviet Union to the United States and back. Both novels display a general trend in this literature to move away from the prescribed paradigms of Jewish American immigrant self-understanding, and toward a more private sense of the immigrant self, a movement away from the familiar confines of immigrant urban enclaves and toward a poetics of place that expands the modalities in which post-Soviet Jewish characters interact with US American space.     

Complexity and inapproximability results for the Power Edge Set problem

We consider the single channel PMU placement problem called the Power Edge Set problem. In this variant of the PMU placement problem, (single channel) PMUs are placed on the edges of an electrical network. Such a PMU measures the current along the edge on which it is placed and the voltage at its two endpoints. The objective is to find the minimum placement of PMUs in the network that ensures its full observability, namely measurement of all the voltages and currents. We prove that PES is NP-hard to approximate within a factor (1.12)-\(\epsilon \), for any \(\epsilon > 0\). On the positive side we prove that PES problem is solvable in polynomial time for trees and grids.     

Aggregate, Disaggregate, and Hybrid Analyses of Ecological Risk Perceptions

Laypeople's perceptions of health and safety risks have been widely studied, but only a few studies have addressed perceptions of ecological hazards. We assembled a list of 39 attributes of ecological hazards from the literatures on comparative risk assessment, ecological health, environmental conservation and management, environmental psychology, and risk perception. In Study 1, 125 laypeople evaluated 83 hazards on subsets of this attribute set. Factor analysis of attribute ratings (averaged over participants) revealed six oblique factors: ecological impacts, human impacts, human benefits, aesthetic impacts, scientific understanding, and controllability. These factors predicted mean judgments of overall riskiness, ecological riskiness, acceptability, and regulatory strictness. In Study 2, 30 laypeople each evaluated 34 hazards on 17 attributes and 3 dependent variables. Aggregate-level factor analysis of these data replicated the appropriate portion of the factor solution and yielded similar regression results. Parallel analyses at the individual-participant level yielded factors that explained less variance in judgments of overall riskiness, ecological riskiness, and acceptability. However, the decrease in explanatory power was much less than is often reported for disaggregate-level analyses of psychometric data. This discrepancy illustrates the importance of distinguishing between the level of analysis (aggregate versus disaggregate) and the focus of analysis (distinctions among hazards versus distinctions among participants). In a hybrid analysis, aggregate-level factor scores predicted individual participants' riskiness judgments reasonably well. Psychometric studies such as these provide a sound empirical basis for selecting attributes of ecological hazards for use in comparative risk assessment.     

What Do People Know About Global Climate Change? 2. Survey Studies of Educated Laypeople

Drawing on results from earlier studies that used open-ended interviews, a questionnaire was developed to examine laypeople's knowledge about the possible causes and effects of global warming, as well as the likely efficacy of possible interventions. It was administered to two well-educated opportunity samples of laypeople. Subjects had a poor appreciation of the facts that (1) if significant global warming occurs, it will be primarily the result of an increase in the concentration of carbon dioxide in the earth's atmosphere, and (2) the single most important source of additional carbon dioxide is the combustion of fossil fuels, most notably coal and oil. In addition, their understanding of the climate issue was encumbered with secondary, irrelevant, and incorrect beliefs. Of these, the two most critical are confusion with the problems of stratospheric ozone and difficulty in differentiating between causes and actions specific to climate and more general good environmental practice.     

The status of research on teleworking and an agenda for future research

Teleworking is a relatively new mode of alternative work arrangements. During its short life, the study of teleworking gained considerable attention in the literature for both its academic relevance and its practical implications for management. This paper provides a comprehensive review of the developments in this area, studying the nature of teleworking, its antecedents, processes and outcomes. Different models and perspectives are presented and analysed with emphasis shared between both positive and negative aspects. Directions for future research on teleworking issues, as well as recommendations for a new research agenda, are offered within a framework of Why , What and How to explore the future of teleworking.