Physical Sciences and Mathematics Commons^™

The Power Of Fair Pricing Mechanisms, Christine Chung, Katrina Ligett, Aaron Roth, Kirk Pruhs

Computer Science Faculty Publications

We explore the revenue capabilities of truthful, monotone (“fair”) allocation and pricing functions for resource constrained auction mechanisms within a general framework that encompasses unlimited supply auctions, knapsack auctions, and auctions with general non-decreasing convex production cost functions. We study and compare the revenue obtainable in each fair pricing scheme to the profit obtained by the ideal omniscient multi-price auction. We show that for capacitated knapsack auctions, no constant pricing scheme can achieve any approximation to the optimal profit, but proportional pricing is as powerful as general monotone pricing. In addition, for auction settings with arbitrary bounded non-decreasing convex production …

Heavy Metal Analysis Of Sabine River And Toledo Bend Reservoir Bed Sediments, Michael A. Janusa

Faculty Posters

Core samples were collected from the Sabine River and Toledo Bend Reservoir beds, digested, and analyzed using atomic absorption spectroscopy for several heavy metals. The magnitude of heavy metal concentrations in the bed sediments and the pattern of deposition can help determine which heavy metals are present, the source of heavy metals found in the fish (bed sediment or water), and the source of the heavy metal pollution, if any: industrial, geologic, or atmospheric.

No Fear: Leadership, "Digital Cowboys" And The "Playstation Generation", Singapore Management University

Perspectives@SMU

Finnish entrepreneur Pekka Viljakainen would be considered as successful by most measures. At only 38 years of age, he has managed a staff of 8,000 across 20 countries from Munich. His information technology (IT) consultancy, Oy Visual Systems, had merged with Tieto, another European IT firm, and Viljakainen was made executive vice-president.

A Visual Analytics System For Metropolitan Transportation, Siyuan Liu, Ce Liu, Qiong Luo, Lionel M. Ni, Huamin Qu

LARC Research Publications

With the increasing availability of metropolitan transportation data, such as those from vehicle GPSs (Global Positioning systems) and road-side sensors, it becomes viable for authorities, operators, as well as individuals to analyze the data for a better understanding of the transportation system and possibly improved utilization and planning of the system. We report our experience in building the VAST (Visual Analytics for Smart Transportation) system. Our key observation is that metropolitan transportation data are inherently visual as they are spatiotemporal around road networks. Therefore, we visualize traffic data together with digital maps and support analytical queries through this interactive visual …

Exploring Information Technologies To Support Shotgun Proteomics, Alexander M. Mendoza

Regis University Student Publications (comprehensive collection)

Shotgun proteomics refers to the direct analysis of complex protein mixtures to create a profile of the proteins present in the cell. These profiles can be used to study the underlying biological basis for cancer development. Closely studying the profiles as the cancer proliferates reveals the molecular interactions in the cell. They provide clues to researchers on potential drug targets to treat the disease. A little more than a decade old, shotgun proteomics is a relatively new form of discovery, one that is data intensive and requires complex data analysis. Early studies indicated a gap between the ability to analyze …

Comparison Of Several Tests For Combining Several Independent Tests, Madhusudan Bhandary, Xuan Zhang

Journal of Modern Applied Statistical Methods

Several tests for combining p-values from independent tests have been considered to address a particular common testing problem. A simulation study shows that Fisher’s (1932) Inverse Chi-square test is optimal based on a power comparison of several different tests.

Discriminant Analysis For Repeated Measures Data: Effects Of Mean And Covariance Misspecification On Bias And Error In Discriminant Function Coefficients, Tolulope T. Sajobi, Lisa M. Lix, Longhai Li, William Laverty

Journal of Modern Applied Statistical Methods

Discriminant analysis (DA) procedures based on parsimonious mean and/or covariance structures have been proposed for repeated measures (RM) data. Bias and means square error of discriminant function coefficients (DFCs) for DA procedures are investigated when the mean and/or covariance structures are correctly specified and misspecified.

Construction Of Control Charts Based On Six Sigma Initiatives For The Number Of Defects And Average Number Of Defects Per Unit, R. Radhakrishnan, P. Balamurugan

Journal of Modern Applied Statistical Methods

A control chart is a statistical device used for the study and control of a repetitive process. In 1931, Shewart suggested control charts based on 3 sigma limits. Today manufacturing companies around the world apply Six Sigma initiatives, with a result offewer product defects. Companies practicing Six Sigma initiatives are expected to produce 3.4 or less number of defects per million opportunities, a concept suggested by Motorola in 1980. If companies practicing Six Sigma initiatives use control limits suggested by Shewhart, then no points will fall outside the control limits due to the improvement in the quality of the process. …

Identification Of Optimal Autoregressive Integrated Moving Average Model On Temperature Data, Olusola Samuel Makinde, Olusoga Akin Fasoranbaku

Journal of Modern Applied Statistical Methods

Autoregressive Integrated Moving Average (ARIMA) processes of various orders are presented to identify an optimal model from a class of models. Parameters of the models are estimated using an Ordinary Least Square (OLS) approach. ARIMA (p, d, q) is formulated for maximum daily temperature data in Ondo and Zaira from January 1995 to November 2005. The choice of ARIMA models of orders p and q is intended to retain persistence in a natural process. To determine the performance of models, Normalized Bayesian Information Criterion is adopted. The ARIMA (1, 1, 1) is adequate for modeling maximum daily temperature in Ondo …

Height-Diameter Relationship In Tree Modeling Using Simultaneous Equation Techniques In Correlated Normal Deviates, S. O. Oyamakin

Journal of Modern Applied Statistical Methods

In other to study the complex simultaneous relationships existing in forest/tree growth modeling, six estimation methods of a simultaneous equation model are examined to determine how they cope with varying degrees of correlation between pairs of random deviates using average parameter estimates. A two-equation simultaneous system assumed covariance matrix was considered. The model was structured to have a mutual correlation between pairs of random deviates: a violation of the assumption of mutual independence between pairs of such random deviates. The correlation between the pairs of normal deviates were generated using three scenarios r = 0.0, 0.3 and 0.5. The performances …

Tests For Correlation On Bivariate Non-Normal Data, L. Beversdorf, Ping Sa

Journal of Modern Applied Statistical Methods

Two statistics are considered to test the population correlation for non-normally distributed bivariate data. A simulation study shows that both statistics control type I error rates well for left-tailed tests and have reasonable power performance.

Lq-Moments For Regional Flood Frequency Analysis: A Case Study For The North-Bank Region Of The Brahmaputra River, India, Abhijit Bhuyan, Munindra Borah

Journal of Modern Applied Statistical Methods

The LQ-moment proposed by Mudholkar, et al. (1998) is used for regional flood frequency analysis of the North-Bank region of the river Brahmaputra, India. Five probability distributions are used for the LQmoment: generalized extreme value (GEV), generalized logistic (GLO) and generalized Pareto (GPA), lognormal (LN3) and Pearson Type III (PE3). The same regional frequency analysis procedure proposed by Hosking (1990) for the L-moment is used for the LQ-moment. Based on the LQ-moment ratio diagram and |Z_i^dist| -statistic criteria, the PE3 distribution is identified as the robust distribution for the study area. For estimation of floods of various …

Explicit Equations For Acf In Autoregressive Processes In The Presence Of Heteroscedasticity Disturbances, Samir Safi

Journal of Modern Applied Statistical Methods

The autocorrelation function, ACF, is an important guide to the properties of a time series. Explicit equations are derived for ACF in the presence of heteroscedasticity disturbances in pth order autoregressive, AR(p), processes. Two cases are presented: (1) when the disturbance term follows the general covariance matrix, Σ , and (2) when the diagonal elements of Σ are not all identical but σ_i,j = 0 ∀i ≠ j.

Type I Error Rates Of The Two-Sample Pseudo-Median Procedure, Nor Aishah Ahad, Abdul Rahman Othman, Sharipah Soaad Syed Yahaya

Journal of Modern Applied Statistical Methods

The performance of the pseudo-median based procedure is examined in terms of controlling Type I error for a two independent groups test. The procedure is a modification of the one-sample Wilcoxon statistic using the pseudo-median of differences between group values as the central measure of location. The proposed procedure was shown to have good control of Type I error rates under the study conditions regardless of distribution type.

Modified Ratio And Product Estimators For Population Mean In Systematic Sampling, Housila P. Singh, Rajesh Tailor, Narendra Kumar Jatwa

Journal of Modern Applied Statistical Methods

The estimation of population mean in systematic sampling is explored. Properties of a ratio and product estimator that have been suggested in systematic sampling are investigated, along with the properties of double sampling. Following Swain (1964), the cost aspect is also discussed.

Estimation Of Parameters Of Johnson’S System Of Distributions, Florence George, K. M. Ramachandran

Journal of Modern Applied Statistical Methods

Fitting distributions to data has a long history and many different procedures have been advocated. Although models like normal, log-normal and gamma lead to a wide variety of distribution shapes, they do not provide the degree of generality that is frequently desirable (Hahn & Shapiro, 1967). To formally represent a set of data by an empirical distribution, Johnson (1949) derived a system of curves with the flexibility to cover a wide variety of shapes. Methods available to estimate the parameters of the Johnson distribution are discussed, and a new approach to estimate the four parameters of the Johnson family is …

Robust Inference For Regression With Spatially Correlated Errors, Juchi Ou, Jeffrey M. Albert

Journal of Modern Applied Statistical Methods

A robust variance estimator for a regression model with spatially correlated errors is proposed using the estimated empirical covariogram. Simulations studies show unbiasedness and robustness for the OLS but not for the GLS estimates. The new robust variance estimation method is applied to hospital quality data.. Stephanie A.

Maximum Log Likelihood Estimation Using Em Algorithm And Partition Maximum Log Likelihood Estimation For Mixtures Of Generalized Lambda Distributions, Steve Su

Journal of Modern Applied Statistical Methods

Two mixture distribution fitting methods based on maximizing the likelihood using generalized lambda distributions are presented. The fitting algorithms are demonstrated on various data and the strengths and weakness of the algorithms which can influence their use under different mixture modeling situations are discussed. The procedures described are available in GLDEX package in R.

A Sequential Monte Carlo Approach For Online Stock Market Prediction Using Hidden Markov Models, Ahani E. Bridget, O. Abass

Journal of Modern Applied Statistical Methods

A sequential Monte Carlo (SMC) algorithm prediction approach is developed based on joint probability distribution in hidden Markov Models (HMM). SMC methods, a general class of Monte Carlo methods, are typically used for sampling from sequences of distributions and simple examples of these algorithms are found extensively throughout the tracking and signal processing literature. Recent developments indicate that these techniques have much more general applicability and can be applied very effectively to statistical inference problems. Due to the problem involved in estimating the parameter of HMM, the HMM is represented in a state space model and the sequential Monte Carlo …

Jmasm31: Manova Procedure For Power Calculations (Spss), Alan Taylor

Journal of Modern Applied Statistical Methods

D’Amico, Neilands & Zambarano (2001) showed how the SPSS MANOVA procedure can be used to conduct power calculations for research designs. This article demonstrates a simple way of entering data required for power calculations into SPSS and provides examples that supplement those given by D’Amico, Neilands & Zambarano.

A Pooled Two-Sample Median Test Based On Density Estimation, Vadim Y. Bichutskiy

Journal of Modern Applied Statistical Methods

A new method based on density estimation is proposed for medians of two independent samples. The test controls the probability of Type I error and is at least as powerful as methods widely used in statistical practice. The method can be implemented using existing libraries in R.

Higher Order Markov Structure-Based Logistic Model And Likelihood Inference For Ordinal Data, Soma Chowdhury Biswas, M. Ataharul Islam, Jamal Nazrul Islam

Journal of Modern Applied Statistical Methods

Azzalini (1994) proposed a first order Markov chain for binary data. Azzalini’s model is extended for ordinal data and introduces a second order model. Further, the test statistics are developed and the power of the test is determined. An application using real data is also presented.

Valine Sulfonamidecinnamic Acid Asymmetric Crystal Reactions, Kraig A. Wheeler, Steven H. Malehorn, Annie E. Egan

Faculty Research and Creative Activity

Racemic and homochiral valine sulfonamidecinnamic acidscrystallize with components aligned by use of thecomplementary features of hydrogen bonds and moleculartopology to give supramolecular dimers. These discretemotifs effectively organize adjacent olefins for UV initiated10 single-crystal-to-single-crystal [2+2] photodimerizationreactions. The racemic crystals produce inversion relatedcyclobutane products, while the desymmetrized crystallinearchitectures of the homochiral phase promote asymmetricphotodimerization with 90% conversion.

Evolution Of Spur-Length Diversity In Aquilegia Petals Is Achieved Solely Through Cell-Shape Anisotropy, Joshua R. Puzey, Sharon J. Gerbode, Scott A. Hodges, Elena M. Kramer, L. Mahadevan

All HMC Faculty Publications and Research

The role of petal spurs and specialized pollinator interactions has been studied since Darwin. Aquilegia petal spurs exhibit striking size and shape diversity, correlated with specialized pollinators ranging from bees to hawkmoths in a textbook example of adaptive radiation. Despite the evolutionary significance of spur length, remarkably little is known about Aquilegia spur morphogenesis and its evolution. Using experimental measurements, both at tissue and cellular levels, combined with numerical modelling, we have investigated the relative roles of cell divisions and cell shape in determining the morphology of the Aquilegia petal spur. Contrary to decades-old hypotheses implicating a discrete meristematic zone …

Understanding Melt Generation Beneath The Slow-Spreading Kolbeinsey Ridge Using (238)U, (230)Th, And (231)Pa Excesses, Lynne J. Elkins, K.W.W. Sims, J. Prytulak, T. Elliot, N. Mattielli, J. Blichert-Toft, J. Blusztajn, N. Dunbar, C. Devey, D. F. Mertz, J. G. Schilling, M. Murrell

Geology Faculty Research and Scholarship

To examine the petrogenesis and sources of basalts from the Kolbeinsey Ridge, one of the shallowest locations along the global ridge system, we present new measurements of Nd, Sr, Hf, and Pb isotopes and U-series disequilibria on 32 axial basalts. Young Kolbeinsey basalts (full-spreading rate = 1.8 cm/yr; 67 degrees 05'-70 degrees 26'N) display ((230)Th/(238)U) < 1 and ((230)Th/(238)U) > 1 with ((230)Th/(238)U) from 0.95 to 1.30 and have low U (11.3-65.6 ppb) and Th (33.0 ppb-2.40 ppm) concentrations. Except for characteristic isotopic enrichment near the Jan Mayen region, the otherwise depleted Kolbeinsey basalts (e. g. (87)Sr/(86)Sr = 0.70272-0.70301, epsilon(Nd) = 8.4-10.5, epsilon(Hf) = 15.4-19.6 …

Combinatorics Of Two-Toned Tilings, Arthur T. Benjamin, Phyllis Chinn, Jacob N. Scott '11, Greg Simay

All HMC Faculty Publications and Research

We introduce the function a(r, n) which counts tilings of length n + r that utilize white tiles (whose lengths can vary between 1 and n) and r identical red squares. These tilings are called two-toned tilings. We provide combinatorial proofs of several identities satisfied by a(r, n) and its generalizations, including one that produces kth order Fibonacci numbers. Applications to integer partitions are also provided.

Proxy Pattern-Mixture Analysis For A Binary Variable Subject To Nonresponse., Rebecca H. Andridge, Roderick J. Little

The University of Michigan Department of Biostatistics Working Paper Series

We consider assessment of the impact of nonresponse for a binary survey

variable Y subject to nonresponse, when there is a set of covariates

observed for nonrespondents and respondents. To reduce dimensionality and

for simplicity we reduce the covariates to a continuous proxy variable X

that has the highest correlation with Y, estimated from a probit

regression analysis of respondent data. We extend our previously proposed

proxy-pattern mixture analysis (PPMA) for continuous outcomes to the binary

outcome using a latent variable approach. The method does not assume data

are missing at random, and creates a framework for sensitivity analyses.

Maximum …

Thermodynamics Of Strongly Interacting Fermions In Two-Dimensional Optical Lattices, Ehsan Khatami, Marcos Rigol

Faculty Publications

We study finite-temperature properties of strongly correlated fermions in two-dimensional optical lattices by means of numerical linked cluster expansions, a computational technique that allows one to obtain exact results in the thermodynamic limit. We focus our analysis on the strongly interacting regime, where the on-site repulsion is of the order of or greater than the band width. We compute the equation of state, double occupancy, entropy, uniform susceptibility, and spin correlations for temperatures that are similar to or below the ones achieved in current optical lattice experiments. We provide a quantitative analysis of adiabatic cooling of trapped fermions in two …

Fabrication And Performance Of A Microfluidic Traveling-Wave Electrophoresis System, K. D. Jo, J. E. Schiffbauer, Boyd F. Edwards, R. L. Carroll, A. T. Timperman

All Physics Faculty Publications

A microfluidic traveling-wave electrophoresis (TWE) system is reported that uses a locally defined traveling electric field wave within a microfluidic channel to achieve band transport and separation. Low voltages, over a range of −0.5 to +0.5 V, are used to avoid electrolysis and other detrimental redox reactions while the short distance between electrodes, 25 μm, provides high electric fields of 200 V cm⁻¹. It is expected that the low voltage requirements will simplify the future development of smaller portable devices. The TWE device uses four interdigitated electrode arrays: one interdigitated electrode array pair is on the top of …

Changing The Way We View Humanity And The Rest Of Nature, Robert Costanza

Institute for Sustainable Solutions Publications and Presentations

An introduction is presented in which the editor discusses various reports within the issue on topics including the idea of ecosystem services, how ecosystem aided to solve the mother of all problems and how ecosystem services offer real solutions to problems.