An efficient parallel immersed boundary algorithm using a pseudo-compressible fluid solver

We propose an efficient algorithm for the immersed boundary method on distributed-memory architectures, with the computational complexity of a completely explicit method and excellent parallel scaling. The algorithm utilizes the pseudo-compressibility method recently proposed by Guermond and Minev [Comptes Rendus Mathematique, 348:581-585, 2010] that uses a directional splitting strategy to discretize the incompressible Navier-Stokes equations, thereby reducing the linear systems to a series of one-dimensional tridiagonal systems. We perform numerical simulations of several fluid-structure interaction problems in two and three dimensions and study the accuracy and convergence rates of the proposed algorithm. For these problems, we compare the proposed algorithm against other second-order projection-based fluid solvers. Lastly, the strong and weak scaling properties of the proposed algorithm are investigated

Operations Management Curricula: Literature Review and Analysis

A review and analysis of studies on the interface between Operations Management (OM) academicians and industry practitioners indicate the existence of a persistent gap between what is being taught and what is relevant to practitioners in their daily jobs. The majority of practitioner studies have been directed at upper management levels, yet academia typically educates students for entry level or management trainee (undergraduate) and mid-management (MBA) positions. A recurring finding was that academicians prefer to teach quantitative techniques while practitioners favor qualitative concepts. The OM curricula literature shows some disagreements between academicians concerning subject matter, and a wide variety of teaching opinions. This paper provides an extensive analytical review of OM curricula literature along with their respective authors’ conclusions. From this analysis we suggest a customer-focused business plan to close the gap between industry and academia. This plan can be modified to account for faculty teaching and research interests, local industry requirements and institution specific factors such as class sizes and resources

MCFM for the Tevatron and the LHC

A summary is given of the current status of the next-to-leading order (NLO) parton-level integrator MCFM. Some details are given about the Higgs + 2-jet process and the production and decay of $t \bar{t}$, both of which have recently been added to the code. Using MCFM, comparisons between the Tevatron running at $\sqrt{s}=2$~TeV and the LHC running at $\sqrt{s}=7$~TeV are made for standard model process including the production of Higgs bosons. The case for running the Tevatron until 16fb$^{-1}$ are accumulated by both detectors is sketched.Comment: Talk presented by R.K Ellis at Loops and Legs in Quantum Field Theory 2010, Woerlitz, Germany, April 25-30, 2010, (6 pages and 4 figures

A nonparametric analysis of the Cournot model

An observer makes a number of observations of an industry producing a homogeneous good. Each observation consists of the market price, the output of individual firms and perhaps information on each firm's production cost. We provide various tests (typically, linear programs) with which the observer can determine if the data set is consistent with the hypothesis that firms in this industry are playing a Cournot game at each observation. When cost information is wholly or partially unavailable, these tests could potentially be used to derive cost information on the firms. This paper is a contribution to the literature that aims to characterize (in various contexts) the restrictions that a data set must satisfy for it to be consistent with Nash outcomes in a game. It is also inspired by the seminal result of Afriat (and the subsequent literature) which addresses similar issues in the context of consumer demand, though one important technical difference from most of these results is that the objective functions of firms in a Cournot game are not necessarily quasiconcave

Estimating Abundance from Counts in Large Data Sets of Irregularly-Spaced Plots using Spatial Basis Functions

Monitoring plant and animal populations is an important goal for both academic research and management of natural resources. Successful management of populations often depends on obtaining estimates of their mean or total over a region. The basic problem considered in this paper is the estimation of a total from a sample of plots containing count data, but the plot placements are spatially irregular and non randomized. Our application had counts from thousands of irregularly-spaced aerial photo images. We used change-of-support methods to model counts in images as a realization of an inhomogeneous Poisson process that used spatial basis functions to model the spatial intensity surface. The method was very fast and took only a few seconds for thousands of images. The fitted intensity surface was integrated to provide an estimate from all unsampled areas, which is added to the observed counts. The proposed method also provides a finite area correction factor to variance estimation. The intensity surface from an inhomogeneous Poisson process tends to be too smooth for locally clustered points, typical of animal distributions, so we introduce several new overdispersion estimators due to poor performance of the classic one. We used simulated data to examine estimation bias and to investigate several variance estimators with overdispersion. A real example is given of harbor seal counts from aerial surveys in an Alaskan glacial fjord.Comment: 37 pages, 7 figures, 4 tables, keywords: sampling, change-of-support, spatial point processes, intensity function, random effects, Poisson process, overdispersio

An Experimental Analysis of Compliance in Dynamic Emissions Markets

Two important design elements for emission trading programs are whether and to what extent firms are able to bank emissions permits, and how these programs are to be enforced. In this paper we present results from laboratory emissions markets designed to investigate enforcement and compliance when these markets allow permit banking. Banking is motivated by a decrease in the aggregate permit supply in the middle of multi-period trading sessions. Consistent with theoretical insights, our experiments suggest that high permit violation penalties have little deterrence value in dynamic emissions markets, and that the main challenge of enforcing these programs is to motivate truthful self-reports of emissions.compliance, enforcement, emissions trading, laboratory experiments, permit markets, permit banking

Imperfect Enforcement of Emissions Trading and Industry Welfare: A Laboratory Investigation

This paper uses laboratory experiments to investigate the performance of emission permit markets when compliance is imperfectly enforced. In particular we examine deviations in observed aggregate payoffs and expected penalties from those derived from a model of risk-neutral payoff-maximizing firms. We find that the experimental emissions markets were reasonably efficient at allocating individual emission control choices despite imperfect enforcement and significant noncompliance. However, violations and expected penalties were lower than predicted when these are predicted to be high, but were about the same as predicted values when these values were predicted to be low. Thus, although a standard model of compliance with emissions trading programs tends to predict significantly higher violations than we observe when subjects have strong incentives to violate their emissions permits, individual emissions control responsibilities are distributed among firms as predicted.enforcement, compliance, emissions trading, permit markets, pollution, laboratory experiments

B2C Mass Customization in the Classroom

The purpose of this article is to describe an internet-based mass customization assignment in Operations Management/Supply Chain Management classes where students utilize the Web site of a company that offers a customized product. Students evaluate the user interface, judge the value proposition of the product they demonstrate, and discuss issues of product design, process design and scheduling, inventory management, Supply Chain Management, marketing, and competitors. The students learn about mass customization from both the producer\u27s perspective and the consumer\u27s perspective. Through their own research and the class presentations students are able to develop a better understanding of the implementation requirements and challenges of mass customization. The assignment is highly interactive and has been successfully used in Operations Management and Supply Chain Management courses at under-graduate and graduate levels and at multiple universities. In addition, practitioners interested in implementing a mass customization process can use the assignment as a brainstorming or benchmarking exercise