Statistics and Probability Commons^™

Divide And Recombine: Autoregressive Models And Stl+, Xiang Han

Open Access Dissertations

In this thesis multiple methods are proposed and applied to the Akamai CIDR time series data. The Akamai network is one of the world's largest distributed-computing platforms, with more than 250,000 servers in more than 80 countries. It is responsible for 15-20 percent of all web traffic. We obtained 110 GB raw CIDR data over a 18 month period, collected on the Akamai network from November 2011 to April 2013. ^ The Seasonal-Trend Decomposition procedure based on loess (STL+) is used to model the CIDR series. Motivated by the CIDR series analysis, we propose a general prediction based model selection …

Spatial Marked Point Processes: Models And Inferences, Yen-Ning E Huang

Open Access Dissertations

A spatial marked point process describes the locations of randomly distributed events in a region, with a mark attached to each observed point. Nowadays, the availability of spatiotemporal data is increasing and many spatiotemporal models are studied with applications in a wide range of disciplines. Spatial marked point processes are then extended to spatiotemporal marked point processes if time component is taken into account. In general, the marks can be quantitative or categorical variables. Independence between points and marks is a convenient assumption, but may not be true in practice. Tests for independence between points and marks are proposed previously, …

The Tessera D&R Computational Environment: Designed Experiments For R-Hadoop Performance And Bitcoin Analysis, Jianfu Li

Open Access Dissertations

D&R is a statistical framework for the analysis of large complex data that enables feasible and practical analysis of large complex data. The analyst selects a division method to divide the data into subsets, applies an analytic method of the analysis to each subset independently with no communication among subsets, selects a recombination method that is applied to the outputs across subsets to form a result of the analytic method for the entire data. The computational tasking of D&R is nearly embarrassingly parallel, so D&R can readily exploit distributed, parallel computational environments, such as our D&R computational environment, Tessera.^ In …

Exploring The Relationship Between K-8 Prospective Teachers’ Algebraic Thinking Proficiency And The Questions They Pose During Diagnostic Algebraic Thinking Interviews, Leigh A. Van Den Kieboom, Marta T. Magiera, John C. Moyer

Mathematics, Statistics and Computer Science Faculty Research and Publications

In this study, we explored the relationship between prospective teachers’ algebraic thinking and the questions they posed during one-on-one diagnostic interviews that focused on investigating the algebraic thinking of middle school students. To do so, we evaluated prospective teachers’ algebraic thinking proficiency across 125 algebra-based tasks and we analyzed the characteristics of questions they posed during the interviews. We found that prospective teachers with lower algebraic thinking proficiency did not ask any probing questions. Instead, they either posed questions that simply accepted and affirmed student responses or posed questions that guided the students toward an answer without probing student thinking. …

Relatively Congruence-Free Regular Semigroups, Peter R. Jones

Mathematics, Statistics and Computer Science Faculty Research and Publications

Yu, Wang, Wu and Ye call a semigroup S τ -congruence-free, where τ is an equivalence relation on S, if any congruence ρ on S is either disjoint from τ or contains τ . A congruence-free semigroup is then just an ω-congruence-free semigroup, where ω is the universal relation. They determined the completely regular semigroups that are τ -congruence-free with respect to each of the Green’s relations. The goal of this paper is to extend their results to all regular semigroups. Such a semigroup is J –congruence-free if and only if it is either a semilattice or has …

Generalized Exponentiated Moment Exponential Distribution, Zafar Iqbal, Syed Anwer Hasnain, Muhammad Salman, Munir Ahmad, Gholamhossein Hamedani

Mathematics, Statistics and Computer Science Faculty Research and Publications

Moment distributions have a vital role in mathematics and statistics, in particular in probability theory, in the perspective research related to ecology, reliability, biomedical field, econometrics, survey sampling and in life-testing. Hasnain (2013) developed an exponentiated moment exponential (EME) distribution and discussed some of its important properties. In the present work, we propose a generalization of EME distribution which we call it generalized EME (GEME) distribution and develop various properties of the distribution. We also present characterizations of the distribution in terms of conditional expectation as well as based on hazard function of the GEME random variable.

Some Remarks On Recent Characterizations Of Continuous Distributions, Gholamhossein Hamedani

Mathematics, Statistics and Computer Science Faculty Research and Publications

We would closely look at two recent published papers dealing with characterizations of certain univariate continuous distributions. We shall explain that the main results reported lack important assumptions. These results nevertheless are based on the conditional expectations of monotone functions of the generalized order statistics. We will also mention that similar results have recently been reported without the assumption of monotonicity of the functions of the generalized order statistics.

Using Graphs To Characterize Nationwide Physician Referral Networks, Ding Tong, Shu-Xia Li, Isuru Ranasinghe, Sudhakar Nuti, Hongyu Zhao, Harlan Krumholz

Yale Day of Data

AIM:

Evaluating physician referral network characteristics can help to understand how physicians and hospitals interact to provide patient services within the US healthcare system and ultimately how this may influence patient outcomes.

METHOD:

We used the 2012-2013 national Physician Referral data from the Centers for Medicare & Medicaid Services (CMS), which consists of 73,071,804 pairs of referrals from one health provider to another in calendar year 2012 and the first two quarters of year 2013 within 30 days of care. These referrals are from 642,144 national-wide physicians and 4,811 hospitals. We obtained information for each provider, physician or hospital, from …

Stratified Meta-Analysis To Examine Data Biases In Lung Cancer Studies Of Refinery Workers, Sherman Selix

Yale Day of Data

Petroleum refineries employ a variety of workers who historically experienced different potentials for asbestos exposure depending on job tasks. Associations between petroleum refinery work and lung cancer related to occupational asbestos exposure have been quantified among various locations, corporations, and time periods. To combine the data from several individual refinery studies and examine an overall effect, a systematic review and stratified meta-analysis was employed. Using set search terms among four databases, 112 potential publications were identified, of which 29 qualified for meta-analysis. Risk estimates and confidence intervals were extracted from these publications to construct four separate datasets. Inverse variance weighting …

Online Targeted Learning, Mark J. Van Der Laan, Samuel D. Lendle

U.C. Berkeley Division of Biostatistics Working Paper Series

We consider the case that the data comes in sequentially and can be viewed as sample of independent and identically distributed observations from a fixed data generating distribution. The goal is to estimate a particular path wise target parameter of this data generating distribution that is known to be an element of a particular semi-parametric statistical model. We want our estimator to be asymptotically efficient, but we also want that our estimator can be calculated by updating the current estimator based on the new block of data without having to revisit the past data, so that it is computationally much …

Lung Flute Improves Symptoms And Health Status In Copd With Chronic Bronchitis: A 26 Week Randomized Controlled Trial, Sanjay Sethi, Jingjing Yin, Pamela K. Anderson

Biostatistics: Faculty Publications

Background: Chronic obstructive pulmonary disease (COPD) is characterized by mucus hypersecretion that contributes to disease related morbidity and is associated with increased mortality. The Lung Flute® is a new respiratory device that produces a low frequency acoustic wave with moderately vigorous exhalation to increase mucus clearance. We hypothesized that the Lung Flute, used on a twice daily basis will provide clinical benefit to patients with COPD with chronic bronchitis.

Methods: We performed a 26 week randomized, non-intervention controlled, single center, open label trial in 69 patients with COPD and Chronic Bronchitis. The primary endpoint was change in respiratory symptoms measured …

Estimation Of The Overall Treatment Effect In The Presence Of Interference In Cluster-Randomized Trials Of Infectious Disease Prevention, Nicole Bohme Carnegie, Rui Wang, Victor De Gruttola

Harvard University Biostatistics Working Paper Series

No abstract provided.

Novel Image Markers For Non-Small Cell Lung Cancer Classification And Survival Prediction, Hongyuan Wang, Fuyong Xing, Hai Su, Arnold J. Stromberg, Lin Yang

Statistics Faculty Publications

BACKGROUND: Non-small cell lung cancer (NSCLC), the most common type of lung cancer, is one of serious diseases causing death for both men and women. Computer-aided diagnosis and survival prediction of NSCLC, is of great importance in providing assistance to diagnosis and personalize therapy planning for lung cancer patients.

RESULTS: In this paper we have proposed an integrated framework for NSCLC computer-aided diagnosis and survival analysis using novel image markers. The entire biomedical imaging informatics framework consists of cell detection, segmentation, classification, discovery of image markers, and survival analysis. A robust seed detection-guided cell segmentation algorithm is proposed to accurately …

Computational Methods For Historical Research On Wikipedia’S Archives, Jonathan Cohen

e-Research: A Journal of Undergraduate Work

This paper presents a novel study of geographic information implicit in the English Wikipedia archive. This project demonstrates a method to extract data from the archive with data mining, map the global distribution of Wikipedia editors through geocoding in GIS, and proceed with a spatial analysis of Wikipedia use in metropolitan cities.

Cox Regression Models With Functional Covariates For Survival Data, Jonathan E. Gellar, Elizabeth Colantuoni, Dale M. Needham, Ciprian M. Crainiceanu

Johns Hopkins University, Dept. of Biostatistics Working Papers

We extend the Cox proportional hazards model to cases when the exposure is a densely sampled functional process, measured at baseline. The fundamental idea is to combine penalized signal regression with methods developed for mixed effects proportional hazards models. The model is fit by maximizing the penalized partial likelihood, with smoothing parameters estimated by a likelihood-based criterion such as AIC or EPIC. The model may be extended to allow for multiple functional predictors, time varying coefficients, and missing or unequally-spaced data. Methods were inspired by and applied to a study of the association between time to death after hospital discharge …

Alterations In Gene Array Patterns In Dendritic Cells From Aged Humans, Jia-Ning Cao, Anshu Agrawal, Edward Sharman, Zhenyu Jia, Sudhir Gupta

Statistics Faculty Research

Dendritic cells (DCs) are major antigen-presenting cells that play a key role in initiating and regulating innate and adaptive immune responses. DCs are critical mediators of tolerance and immunity. The functional properties of DCs decline with age. The purpose of this study was to define the age-associated molecular changes in DCs by gene array analysis using Affymatrix GeneChips. The expression levels of a total of 260 genes (1.8%) were significantly different (144 down-regulated and 116 upregulated) in monocyte-derived DCs (MoDCs) from aged compared to young human donors. Of the 260 differentially expressed genes, 24% were down-regulated by more than 3-fold, …

Targeted Learning Of An Optimal Dynamic Treatment, And Statistical Inference For Its Mean Outcome, Mark J. Van Der Laan, Alexander R. Luedtke

U.C. Berkeley Division of Biostatistics Working Paper Series

Suppose we observe n independent and identically distributed observations of a time-dependent random variable consisting of baseline covariates, initial treatment and censoring indicator, intermediate covariates, subsequent treatment and censoring indicator, and a final outcome. For example, this could be data generated by a sequentially randomized controlled trial, where subjects are sequentially randomized to a first line and second line treatment, possibly assigned in response to an intermediate biomarker, and are subject to right-censoring. In this article we consider estimation of an optimal dynamic multiple time-point treatment rule defined as the rule that maximizes the mean outcome under the dynamic treatment, …

On Second Order Elliptic Equations And Variational Inequalities With Anisotropic Principal Operators, Vy Khoi Le

Mathematics and Statistics Faculty Research & Creative Works

This paper is about boundary value problems of the form where ƨ is a convex function of ξ.∈ RN rather than a function of the norm|ξ|. The problem is formulated appropriately in an anisotropic Orlicz-Sobolev space associated with ƨ. We study the existence of solutions and some other properties of the above problem and its corresponding variational inequality in such space.

Generalized Least-Squares Regressions Iv: Theory And Classification Using Generalized Means, Nataniel Greene

Publications and Research

The theory of generalized least-squares is reformulated here using the notion of generalized means. The generalized least-squares problem seeks a line which minimizes the average generalized mean of the square deviations in x and y. The notion of a generalized mean is equivalent to the generating function concept of the previous papers but allows for a more robust understanding and has an already existing literature. Generalized means are applied to the task of constructing more examples, simplifying the theory, and further classifying generalized least-squares regressions.

Existence Of Disjoint Weakly Mixing Operators That Fail To Satisfy The Disjoint Hypercyclicity Criterion, Rebecca Sanders, Stanislav Shkarin

Mathematics, Statistics and Computer Science Faculty Research and Publications

No abstract provided.