Pocketbook Money Keys

A Poem

Budget Feasible Mechanisms

We study a novel class of mechanism design problems in which the outcomes are constrained by the payments. This basic class of mechanism design problems captures many common economic situations, and yet it has not been studied, to our knowledge, in the past. We focus on the case of procurement auctions in which sellers have private costs, and the auctioneer aims to maximize a utility function on subsets of items, under the constraint that the sum of the payments provided by the mechanism does not exceed a given budget. Standard mechanism design ideas such as the VCG mechanism and its variants are not applicable here. We show that, for general functions, the budget constraint can render mechanisms arbitrarily bad in terms of the utility of the buyer. However, our main result shows that for the important class of submodular functions, a bounded approximation ratio is achievable. Better approximation results are obtained for subclasses of the submodular functions. We explore the space of budget feasible mechanisms in other domains and give a characterization under more restricted conditions

Review of: Eleanor Singer & Phyllis M. Endreny, Reporting on Risk

Review of: Eleanor Singer & Phyllis M. Endreny, Reporting on Risk (Russell Sage Foundation 1993). Acknowledgments, index, notes, preface, references, tables. LC 92-40130; ISBN 0-87154-801-1. [256 pp. Cloth $24.95. 112 East 64th Street, New York NY 10021.

Biomarkers in sepsis.

Purpose of review: This review discusses the current developments in biomarkers for sepsis. Recent findings: With quantum leaps in technology, an array of biomarkers will become available within the next decade as point-of-care tools that will likely revolutionize the management of sepsis. These markers will facilitate early and accurate diagnosis, faster recognition of impending organ dysfunction, optimal selection and titration of appropriate therapies, and more reliable prognostication of risk and outcome. These diagnostics will also enable an improved characterization of the biological phenotype underlying sepsis and thus a better appreciation of the condition. Summary: The potential for novel biomarkers in sepsis will need to be properly realized with considerable funding, academic–industry collaborations, appropriate investigations and validation in heterogenous populations, but these developments do hold the capacity to transform patient care and outcomes

Twenty Questions

In the first of this new series for the journal, Peter Singer responds to questions from the editors and Theron Pummer

Development of Economic Water Usage Sensor and Cyber-Physical Systems Co-Simulation Platform for Home Energy Saving

In this thesis, two Cyber-Physical Systems (CPS) approaches were considered to reduce residential building energy consumption. First, a flow sensor was developed for residential gas and electric storage water heaters. The sensor utilizes unique temperature changes of tank inlet and outlet pipes upon water draw to provide occupant hot water usage. Post processing of measured pipe temperature data was able to detect water draw events. Conservation of energy was applied to heater pipes to determine relative internal water flow rate based on transient temperature measurements. Correlations between calculated flow and actual flow were significant at a 95% confidence level. Using this methodology, a CPS water heater controller can activate existing residential storage water heaters according to occupant hot water demand. The second CPS approach integrated an open-source building simulation tool, EnergyPlus, into a CPS simulation platform developed by the National Institute of Standards and Technology (NIST). The NIST platform utilizes the High Level Architecture (HLA) co-simulation protocol for logical timing control and data communication. By modifying existing EnergyPlus co-simulation capabilities, NIST’s open-source platform was able to execute an uninterrupted simulation between a residential house in EnergyPlus and an externally connected thermostat controller. The developed EnergyPlus wrapper for HLA co-simulation can allow active replacement of traditional real-time data collection for building CPS development. As such, occupant sensors and simple home CPS product can allow greater residential participation in energy saving practices, saving up to 33% on home energy consumption nationally

ENGINEERING A VISUAL FIELD

Of the branches of mathematics, geometry has, from the earliest Hellenic period, been given a curious position that straddles empirical and exact science. Its standing as an empirical and approximate science stems from the practical pursuits of artistic drafting, land surveying and measuring in general. From the prominence of visual application, such as figures and constructions in the twentieth century Einstein's General Theory of Relativity holds that the geometry of space-time is dependent upon physical quantities