Physical Sciences and Mathematics Commons^™

Comparison Of Estimators In Glm With Binary Data, D. M. Sakate, D. N. Kashid

Journal of Modern Applied Statistical Methods

Maximum likelihood estimates (MLE) of regression parameters in the generalized linear models (GLM) are biased and their bias is non negligible when sample size is small. This study focuses on the GLM with binary data with multiple observations on response for each predictor value when sample size is small. The performance of the estimation methods in Cordeiro and McCullagh (1991), Firth (1993) and Pardo et al. (2005) are compared for GLM with binary data using an extensive Monte Carlo simulation study. Performance of these methods for three real data sets is also compared.

Objective Priors For Estimation Of Extended Exponential Geometric Distribution, Pedro L. Ramos, Fernando A. Moala, Jorge A. Achcar

Journal of Modern Applied Statistical Methods

A Bayesian analysis was developed with different noninformative prior distributions such as Jeffreys, Maximal Data Information, and Reference. The aim was to investigate the effects of each prior distribution on the posterior estimates of the parameters of the extended exponential geometric distribution, based on simulated data and a real application.

Bayesian Estimation Of The Parameters Of Two-Component Mixture Of Rayleigh Distribution Under Doubly Censoring, Tahassum N. Sindhu, Navid Feroze, Muhammad Aslam

Journal of Modern Applied Statistical Methods

Recently, the Bayesian analysis of the two-component mixture of lifetime models under singly type I censored samples was discussed. The Bayes estimation of the parameters of mixture of two Rayleigh distributions (MTRD) is developed under doubly censoring. Different informative priors, under squared error loss function and k-loss function, have been assumed for the posterior estimation. The performance of different estimators has been compared in terms of posterior risks by analyzing the simulated and real life data sets.

Life Testing Analysis Of Failure Censored Generalized Exponentiated Data, Anwar Hassan, Mehraj Ahmad

Journal of Modern Applied Statistical Methods

A generalized exponential distribution is considered for analyzing lifetime data; such statistical models are applicable when the observations are available in an ordered manner. This study examines failure censored data, which consist of testing n items and terminating the experiment when a pre-assigned number of items, for example r ( < n), have failed. Due to scale and shape parameters, both have flexibility for analyzing different types of lifetime data. This distribution has increasing, decreasing and a constant hazard rate depending on the shape parameter. This study provides maximum likelihood estimation and uniformly minimum variance unbiased techniques for the estimation of reliability of a component. Numerical computation was conducted on a data set and a comparison of the performance of two different techniques is presented.

Some Methods Of Estimation From Censored Samples In Exponential And Gamma Models, R R. L Kantam, B Sriram

Journal of Modern Applied Statistical Methods

Two popular life testing models exponential and one where its generalization is gamma are considered. Estimation of scale parameter from a general Type-II doubly censored sample is attempted by the principle of maximum likelihood method. Resulting equations found to be giving iterative solutions. As an alternative to iterative solution certain admissible modifications to the estimating equations are suggested in special cases. The resulting estimates are compared with the exact maximum likelihood estimates analytically or through simulation. The results are also extended for reliability estimation.

Double Bootstrap Confidence Interval Estimates With Censored And Truncated Data, Jayanthi Arasan, Mohd B. Adam

Journal of Modern Applied Statistical Methods

Traditional inferential procedures often fail with censored and truncated data, especially when sample sizes are small. In this paper we evaluate the performances of the double and single bootstrap interval estimates by comparing the double percentile (DB-p), double percentile-t (DB-t), single percentile (B-p), and percentile-t (B-t) bootstrap interval estimation methods via a coverage probability study when the data is censored using the log logistic model. We then apply the double bootstrap intervals to real right censored lifetime data on 32 women with breast cancer and failure data on 98 brake pads where all the observations were left truncated.

Contrast Of Bayesian And Classical Sample Size Determination, Farhana Sadia, Syed S. Hossain

Journal of Modern Applied Statistical Methods

Sample size determination is a prerequisite for statistical surveys. A comprehensive overview of the Bayesian approach for computation of the sample size, and a comparison with classical approaches, is presented. Two surveys are taken as example to illustrate the accuracy and efficiency of each approach, and to make recommendations about which method is preferred. The Bayesian approach of sample size determination may require fewer subjects if proper prior information is available.

Estimation Of Gumbel Parameters Under Ranked Set Sampling, Omar M. Yousef, Sameer A. Al-Subh

Journal of Modern Applied Statistical Methods

Consider the MLEs (maximum likelihood estimators) of the parameters of the Gumbel distribution using SRS (simple random sample) and RSS (ranked set sample) and the MOMEs (method of moment estimators) and REGs (regression estimators) based on SRS. A comparison between these estimators using bias and MSE (mean square error) was performed using simulation. It appears that the MLE based on RSS can be a robust competitor to the MLE based on SRS.

Estimates And Forecasts Of Garch Model Under Misspecified Probability Distributions: A Monte Carlo Simulation Approach, Olaoluwa S. Yaya, Olusanya E. Olubusoye, Oluwadare O. Ojo

Journal of Modern Applied Statistical Methods

The effect of misspecification of correct sampling probability distribution of Generalized Autoregressive Conditionally Heteroscedastic (GARCH) processes is considered. The three assumed distributions are the normal, Student t, and generalized error distributions. The GARCH process is sampled using one of the distributions and the model is estimated based on the three distributions in each sample. Parameter estimates and forecast performance are used to judge the estimated model for performance. The AR-GARCH-GED performed better on the three assumed distributions; even, when Student t distribution is assumed, AR-GARCH-Student t does not perform as the best model.

Local Bandwidths For Improving Performance Statistics Of Model-Robust Regression 2, Efosa Edionwe, Julian L. Mbegbu

Journal of Modern Applied Statistical Methods

Model-Robust Regression 2 (MRR2) method is a semi-parametric regression approach that combines parametric and nonparametric fits. The bandwidth controls the smoothness of the nonparametric portion. We present a methodology for deriving data-driven local bandwidth that enhances the performance of MRR2 method for fitting curves to data generated from designed experiments.

Bayesian Inference For Volatility Of Stock Prices, Juliet G. D'Cunha, K. A. Rao

Journal of Modern Applied Statistical Methods

Lognormal distribution is widely used in the analysis of failure time data and stock prices. Maximum likelihood and Bayes estimator of the coefficient of variation of lognormal distribution along with confidence/credible intervals are developed. The utility of Bayes procedure is illustrated by analyzing prices of selected stocks.

Front Matter, Jmasm Editors

Journal of Modern Applied Statistical Methods

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End Matter, Jmasm Editors

Journal of Modern Applied Statistical Methods

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Vol. 13, No. 2 (Full Issue), Jmasm Editors

Journal of Modern Applied Statistical Methods

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Measuring Privacy Disclosures In Url Query Strings, Andrew G. West, Adam J. Aviv

Andrew G. West

Publicly posted URLs may contain a wealth of information about the identities and activities of the users who share them. URLs often utilize query strings (i.e., key-value pairs appended to the URL path) as a means to pass session parameters and form data. While often benign and necessary to render the web page, query strings sometimes contain tracking mechanisms, user names, email addresses, and other information that users may not wish to publicly reveal. In isolation this is not particularly problematic, but the growth of Web 2.0 platforms such as social networks and micro-blogging means URLs (often copy-pasted from web …

Intelligent Firefly Algorithm For Global Optimization, Seif-Eddeen K. Fateen, Adrián Bonilla-Petriciolet

Seif-Eddeen K Fateen

Intelligent firefly algorithm (IFA) is a novel global optimization algorithm that aims to improve the performance of the firefly algorithm (FA), whichwas inspired by the flashing communication signals among firefly swarms. This chapter introduces the IFA modification and evaluates its performance in comparison with the original algorithm in twenty multi-dimensional benchmark problems. The results of those numerical experiments show that IFA outperformed FA in terms of reliability and effectiveness in all tested benchmark problems. In some cases, the global minimum could not have been successfully identified via the firefly algorithm, except with the proposed modification for FA.

Differential Effects Of Canopy Trimming And Litter Deposition On Litterfall And Nutrient Dynamics In A Wet Subtropical Forest, Steven J. Hall, Whendee L. Silver, Grizelle González

Steven J. Hall

Humid tropical forests have the highest rates of litterfall production globally, which fuels rapid nutrient recycling and high net ecosystem production. Severe storm events significantly alter patterns in litterfall mass and nutrient dynamics through a combination of canopy disturbance and litter deposition. In this study, we used a large-scale long-term manipulation experiment to explore the separate and combined effects of canopy trimming and litter deposition on litterfall rates and litter nutrient concentrations and content. The deposition of fine litter associated with the treatments was equivalent to more than two times the annual fine litterfall mass and nutrient content in control …

Complex Spatiotemporal Responses Of Global Terrestrial Primary Production To Climate Change And Increasing Atmospheric Co2 In The 21st Century, Shufen Pan, Hanqin Tian, Shree R. S. Dangal, Chi Zhang, Jia Yang, Bo Tao, Zhiyun Ouyang, Xiaoke Wang, Chaoqun (Crystal) Lu, Wei Ren, Kamaljit Banger, Qichun Yang, Bowen Zhang, Xia Li

Chaoqun (Crystal) Lu

Quantitative information on the response of global terrestrial net primary production (NPP) to climate change and increasing atmospheric CO2 is essential for climate change adaptation and mitigation in the 21st century. Using a process-based ecosystem model (the Dynamic Land Ecosystem Model, DLEM), we quantified the magnitude and spatiotemporal variations of contemporary (2000s) global NPP, and projected its potential responses to climate and CO2 changes in the 21st century under the Special Report on Emission Scenarios (SRES) A2 and B1 of Intergovernmental Panel on Climate Change (IPCC). We estimated a global terrestrial NPP of 54.6 (52.8–56.4) PgC yr−1 as a result …

Rnase L Interacts With Filamin A To Regulate Actin Dynamics And Barrier Function For Viral Entry, Krishnamurthy Malathi, Mohammad Adnan Siddiqui, Shubham Dayal, Merna Naji, Heather J, Ezelle, Chun Zeng, Aimin Zhou, Bret A. Hassel

Chemistry Faculty Publications

The actin cytoskeleton and its network of associated proteins constitute a physical barrier that viruses must circumvent to gain entry into cells for productive infection. The mechanisms by which the physical signals of infection are sensed by the host to activate an innate immune response are not well understood. The antiviral endoribonuclease RNase L is ubiquitously expressed in a latent form and activated upon binding 2-5A, a unique oligoadenylate produced during viral infections. We provide evidence that RNase L in its inactive form interacts with the actin-binding protein Filamin A to modulate the actin cytoskeleton and inhibit virus entry. Cells …

X-Ray Emission From Magnetic Massive Stars, Yaël Nazé, Véronique Petit, Melanie Rinbrand, David H. Cohen, Stanley P. Owocki, Asif Ud-Doula, Gregg A. Wade

Aerospace, Physics, and Space Science Faculty Publications

Magnetically confined winds of early-type stars are expected to be sources of bright and hard X-rays. To clarify the systematics of the observed X-ray properties, we have analyzed a large series of Chandra and XMM-Newton observations, corresponding to all available exposures of known massive magnetic stars (over 100 exposures covering 60% of stars compiled in the catalog of Petit et al.). We show that the X-ray luminosity is strongly correlated with the stellar wind mass-loss rate, with a power-law form that is slightly steeper than linear for the majority of the less luminous, lower- B stars and flattens for the …

A Combinatorial Proof Of A Theorem Of Katsuura, Brian K. Miceli

Mathematics Faculty Research

We give a combinatorial proof of an algebraic result of Katsuura's. Moreover, we use the proof of this result to shed some light on an interesting property of the result itself.

A Parallel Genetic Algorithm For Tuning Neural Networks, Nathan Chadderdon, Ben Harsha, Steven Bogaerts

Annual Student Research Poster Session

One challenge in using artificial neural networks is how to determine appropriate parameters for network structure and learning. Often parameters such as learning rate or number of hidden units are set arbitrarily or with a general "intuition" as to what would be most effective. The goal of this project is to use a genetic algorithm to tune a population of neural networks to determine the best structure and parameters. This paper considers a genetic algorithm to tune the number of hidden units, learning rate, momentum, and number of examples viewed per weight update. Experiments and results are discussed for two …

The Mass Evolution Of The First Galaxies: Stellar Mass Functions And Star Formation Rates At 4 < Z < 7 In The Candels Goods-South Field, K. Duncan, C. J. Conselice, A. Mortlock, W. G. Hartley, Y. Guo, H. C. Ferguson, R. Davé, Y. Lu, J. Owensworth, M. L. N. Ashby, A. Dekel, M. Dickinson, S. Faber, M. Giavalisco, N. Grogin, Dale D. Kocevski, A. Koekemoer, R. S. Somerville, C. E. White

Physics and Astronomy Faculty Publications

We measure new estimates for the galaxy stellar mass function and star formation rates for samples of galaxies at z ∼ 4, 5, 6 and 7 using data in the CANDELS GOODS South field. The deep near-infrared observations allow us to construct the stellar mass function at z ≥ 6 directly for the first time. We estimate stellar masses for our sample by fitting the observed spectral energy distributions with synthetic stellar populations, including nebular line and continuum emission. The observed UV luminosity functions for the samples are consistent with previous observations; however, we find that the observed M_{UV …}

Measurement Of “Pretzelosity” Asymmetry Of Charged Pion Production In Semi-Inclusive Deep Inelastic Scattering On A Polarized 3He Target, K. Allada, C. Dutta, A. Kolarkar, Wolfgang Korsch, Y. Zhang, X. Qian, J. Huang, J. Katich, Y. Wang, K. Aniol, J. R. M. Annand, T. Averett

Physics and Astronomy Faculty Publications

An experiment to measure single-spin asymmetries of semi-inclusive production of charged pions in deep-inelastic scattering on a transversely polarized ³He target was performed at Jefferson Laboratory in the kinematic region of 0.16<x<0.35 and 1.42<2.7 GeV² Pretzelosity asymmetries on ³He, which are expressed as the convolution of the h^⊥_1T transverse-momentum-dependent distribution functions and the Collins fragmentation functions in the leading order, were measured for the first time. Under the effective polarization approximation, we extracted the corresponding neutron asymmetries from the measured ³He asymmetries and cross-section ratios between the proton and ³He. Our results show that both …

Nonlinear Optimal Filter Technique For Analyzing Energy Depositions In Tes Sensors Driven Into Saturation, B. Shank, J. J. Yen, Blas Cabrera, J. M. Kreikebaum, R. Moffatt, P. Redl, Betty A. Young, P. L. Brink, M. Cherry, A. Tomada

Physics

We present a detailed thermal and electrical model of superconducting transition edge sensors (TESs) connected to quasiparticle (qp) traps, such as the W TESs connected to Al qp traps used for CDMS (Cryogenic Dark Matter Search) Ge and Si detectors. We show that this improved model, together with a straightforward time-domain optimal filter, can be used to analyze pulses well into the nonlinear saturation region and reconstruct absorbed energies with optimal energy resolution.

Weak Measurement And Bohmian Conditional Wave Functions, Travis Norsen

Physics: Faculty Publications

It was recently pointed out (and demonstrated experimentally) by Lundeen et al. that the wave function of a particle (more precisely, the wave function possessed by each member of an ensemble of identically-prepared particles) can be "directly measured" using weak measurement. Here it is shown that if this same technique is applied, with appropriate post-selection, to one particle from a (perhaps entangled) multi-particle system, the result is precisely the so-called "conditional wave function" of Bohmian mechanics. Thus, a plausibly operationalist method for defining the wave function of a quantum mechanical sub-system corresponds to the natural definition of a sub-system wave …

Using Interviews In Cer Projects: Options, Considerations, And Limitations, Deboarh G. Herrington, Patrick L. Daubenmire

Peer Reviewed Articles

Interviews can be a powerful chemistry education research tool. Different from an assessment score or Likert-scale survey number, interviews can provide the researcher with a way to examine and describe what we cannot see, aspects such as feelings, thoughts, or explanations of thinking or behavior. Most people have no doubt seen countless interviews on TV news and talk shows. These sessions might convey interviewing as a spontaneous, easy, and straightforward process. However, using interviews as a meaningful research tool requires considerable thought, preparation, and practice. This chapter provides a general introduction to the use of interviews as a tool within …

Separation Of The Ribbon From Globally Distributed Energetic Neutral Atom Flux Using The First Five Years Of Ibex Observations, N. A. Schwadron, E. Moebius, S. A. Fuselier, D. J. Mccomas, H. O. Funsten, Paul H. Janzen, Daniel B. Reisenfeld, H. Kucharek, M. A. Lee, K. Fairchild, F. Allegrini, M. Dayeh, G. Livadiotis, M. Reno, M. Bzowski, J. M. Sokol, M. A. Kubiak, E. R. Christian, R. Demajistre, P. Frisch, A. Galli, P. Wurz, M. Gruntman

Physics and Astronomy Faculty Publications

The Interstellar Boundary Explorer (IBEX) observes the IBEX ribbon, which stretches across much of the sky observed in energetic neutral atoms (ENAs). The ribbon covers a narrow (∼20^◦–50^◦) region that is believed to be roughly perpendicular to the interstellar magnetic field. Superimposed on the IBEX ribbon is the globally distributed flux that is controlled by the processes and properties of the heliosheath. This is a second study that utilizes a previously developed technique to separate ENA emissions in the ribbon from the globally distributed flux. A transparency mask is applied over the ribbon and …

A Regional Look At Hanpp: Human Consumption Is Increasing, Npp Is Not, Steven W. Running

Ecosystem and Conservation Sciences Faculty Publications

Abdi et al (2014 Environ. Res. Lett. 9 094003), have adapted the concept of comparing supply and demand of annual plant production known as human appropriation of net primary production (HANPP) to a region of the Sahel with rapid population growth. They found that HANPP more than doubled over the study period of 2000–2010, from 19% to 41%, suggesting increasing vulnerability of these populations to food insecurity.

Does The Worsening Galactic Cosmic Radiation Environment Observed By Crater Preclude Future Manned Deep Space Exploration?, Nathan A. Schwadron, J. B. Blake, Anthony Case, Colin J. Joyce, Justin Kasper, J. E. Mazur, N. Petro, M. Quinn, Jamie A. Porter, Charles W. Smith, Sonya S. Smith, Harlan E. Spence, Lawrence W. Townsend, R. Turner, Jody K. Wilson, Cary Zeitlin

Physics & Astronomy

Abstract

The Sun and its solar wind are currently exhibiting extremely low densities and magnetic field strengths, representing states that have never been observed during the space age. The highly abnormal solar activity between cycles 23 and 24 has caused the longest solar minimum in over 80 years and continues into the unusually small solar maximum of cycle 24. As a result of the remarkably weak solar activity, we have also observed the highest fluxes of galactic cosmic rays in the space age and relatively small solar energetic particle events. We use observations from the Cosmic Ray Telescope for the …