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Articles 2371 - 2400 of 16838

Full-Text Articles in Physical Sciences and Mathematics

Precipitation Modulation By The Saint Lawrence River Valley In Association With Transitioning Tropical Cyclones, Shawn M. Milrad, Eyad H. Atallah, John R. Gyakum Jun 2018

Precipitation Modulation By The Saint Lawrence River Valley In Association With Transitioning Tropical Cyclones, Shawn M. Milrad, Eyad H. Atallah, John R. Gyakum

Shawn M. Milrad

The St. Lawrence River valley (SLRV) is an important orographic feature in eastern Canada that can affect surface wind patterns and contribute to locally higher amounts of precipitation. The impact of the SLRV on precipitation distributions associated with transitioning, or transitioned, tropical cyclones that approached the region is assessed. Such cases can result in heavy precipitation during the warm season, as during the transition of Hurricane Ike (2008). Thirty-eight tropical cyclones tracked within 500 km of the SLRV from 1979 to 2011. Utilizing the National Centers for Environmental Prediction (NCEP) North American Regional Reanalysis (NARR), 19 of the 38 cases …


A Diagnostic Examination Of Consecutive Extreme Cool-Season Precipitation Events At St. John's, Newfoundland, In December 2008, Shawn M. Milrad, Eyad H. Atallah, John R. Gyakum Jun 2018

A Diagnostic Examination Of Consecutive Extreme Cool-Season Precipitation Events At St. John's, Newfoundland, In December 2008, Shawn M. Milrad, Eyad H. Atallah, John R. Gyakum

Shawn M. Milrad

St. John’s, Newfoundland, Canada (CYYT), is frequently affected by extreme precipitation events, particularly in the cool season (October–April). Previous work classified precipitation events at CYYT into categories by precipitation amount and a manual synoptic typing was performed on the 50 median extreme precipitation events, using two separate methods. Here, consecutive extreme precipitation events in December 2008 are analyzed. These events occurred over a 6-day period and produced over 125 mm of precipitation at CYYT. The first manual typing method, using a backward-trajectory analysis, results in both events being classified as “southwest,” which were previously defined as the majority of the …


A Meteorological Analysis Of The 2013 Alberta Flood: Antecendent Large-Scale Flow Pattern And Synoptic-Dynamic Characteristics, Shawn M. Milrad, John R. Gyakum, Eyad H. Atallah Jun 2018

A Meteorological Analysis Of The 2013 Alberta Flood: Antecendent Large-Scale Flow Pattern And Synoptic-Dynamic Characteristics, Shawn M. Milrad, John R. Gyakum, Eyad H. Atallah

Shawn M. Milrad

The 19–21 June 2013 Alberta flood was the costliest (CAD $6 billion) natural disaster in Canadian history. The flood was caused by a combination of above-normal spring snowmelt in the Canadian Rockies, large antecedent precipitation, and an extreme rainfall event on 19–21 June that produced rainfall totals of 76 mm in Calgary and 91 mm in the foothills. As is typical of flash floods along the Front Range of the Rocky Mountains, rapidly rising streamflow proceeded to move downhill (eastward) into Calgary.

A meteorological analysis traces an antecedent Rossby wave train across the North Pacific Ocean, starting with intense baroclinic …


A Diagnostic Examination Of The Eastern Ontario And Western Quebec Wintertime Convection Event Of 28 January 2010, Shawn M. Milrad, John R. Gyakum, Eyad H. Atallah, Jennifer F. Smith Jun 2018

A Diagnostic Examination Of The Eastern Ontario And Western Quebec Wintertime Convection Event Of 28 January 2010, Shawn M. Milrad, John R. Gyakum, Eyad H. Atallah, Jennifer F. Smith

Shawn M. Milrad

The priority of an operational forecast center is to issue watches, warnings, and advisories to notify the public about the inherent risks and dangers of a particular event. Occasionally, events occur that do not meet advisory or warning criteria, but still have a substantial impact on human life and property. Short-lived snow bursts are a prime example of such a phenomenon. While these events are typically characterized by small snow accumulations, they often cause very low visibilities and rapidly deteriorating road conditions, both of which are a major hazard to motorists. On the afternoon of 28 January 2010, two such …


Dynamical And Precipitation Structures Of Poleward-Moving Tropical Cyclones In Eastern Canada, 1979-2005, Shawn M. Milrad, Eyad H. Atallah, John R. Gyakum Jun 2018

Dynamical And Precipitation Structures Of Poleward-Moving Tropical Cyclones In Eastern Canada, 1979-2005, Shawn M. Milrad, Eyad H. Atallah, John R. Gyakum

Shawn M. Milrad

Tropical cyclones in the western North Atlantic basin are a persistent threat to human interests along the east coast of North America. Occurring mainly during the late summer and early autumn, these storms often cause strong winds and extreme rainfall and can have a large impact on the weather of eastern Canada. From 1979 to 2005, 40 named (by the National Hurricane Center) tropical cyclones tracked over eastern Canada. Based on the time tendency of the low-level (850–700 hPa) vorticity, the storms are partitioned into two groups: ‘‘intensifying’’ and ‘‘decaying.’’ The 16 intensifying and 12 decaying cases are then analyzed …


A Meteorological Analysis Of Important Contributions To The 1999-2005 Canadian Prairie Drought, Lisa M. Hryciw, Eyad H. Atallah, Shawn M. Milrad, John R. Gyakum Jun 2018

A Meteorological Analysis Of Important Contributions To The 1999-2005 Canadian Prairie Drought, Lisa M. Hryciw, Eyad H. Atallah, Shawn M. Milrad, John R. Gyakum

Shawn M. Milrad

Drought is a complex natural hazard that is endemic to the Canadian prairies. The 1999–2005 Canadian prairie drought, which had great socioeconomic impacts, was meteorologically unique in that it did not conform to the traditional persistent positive Pacific–North American (PNA) pattern and west coast ridging paradigm normally associated with prairie drought. The purpose of this study is to diagnose the unique synoptic-scale mechanisms responsible for modulating subsidence during this drought. Using 30-day running means of the percent of normal precipitation from station data, key severe dry periods during 1999–2005 are identified. Analysis of the mean fields from reanalysis data shows …


A Thermodynamic Analysis Of An Intense North American Arctic Air Mass, Jessica K. Turner, John Gyakum, Shawn M. Milrad Jun 2018

A Thermodynamic Analysis Of An Intense North American Arctic Air Mass, Jessica K. Turner, John Gyakum, Shawn M. Milrad

Shawn M. Milrad

Northwestern Canada is a genesis region of arctic air masses often considered to be formed primarily through radiative processes. However, the details of their life cycle are poorly understood. This paper examines the formation, maintenance, and dissipation of an intense and long-lived arctic air mass, using a thermodynamic budget analysis.

The airmass formation is characterized by a deep-layer, multistage process that begins with snow falling into a nascent air mass. Radiative cooling from cloud tops begins the process. After the snow abates and clear skies are observed, the surface temperature drops rapidly, aided by the high emissivity of fresh snow …


Inversion Copulas From Nonlinear State Space Models With An Application To Inflation Forecasting, Michael S. Smith, Worapree Ole Maneesoonthorn May 2018

Inversion Copulas From Nonlinear State Space Models With An Application To Inflation Forecasting, Michael S. Smith, Worapree Ole Maneesoonthorn

Michael Stanley Smith

We propose the construction of copulas through the inversion of nonlinear state space models. These copulas allow for new time series models that have the same serial dependence structure as a state space model, but with an arbitrary marginal distribution, and flexible density forecasts. We examine the time series properties of the copulas, outline serial dependence measures, and estimate the models using likelihood-based methods. Copulas constructed from three example state space models are considered: a stochastic volatility model with an unobserved component, a Markov switching autoregression, and a Gaussian linear unobserved component model. We show that all three inversion copulas …


Developing A Mathematical Social Machine For Computational Network Analysis, Manfred Minimair May 2018

Developing A Mathematical Social Machine For Computational Network Analysis, Manfred Minimair

Manfred Minimair

A social mathematical machine is a networked system integrating humans and software to cooperatively solve mathematical problems. The software system MathChat impelments an instance of a social mathematical machine for collaboratively carrying out mathematical computations by entering instructions in a command shell. The software design of the MathChat system tightly integrates chat with command entry to support user communication and coordination. A theoretical model for the MathChat system is proposed. The theoretical model is based on the psychological theory of Distributed Cognition and the formalism of Message Passing in distributed computation, which allows formalizing the knowledge acquired by the system …


Distance-Varying Assortativity And Clustering Of The International Trade Network, Angela Abbate, Luca De Benedictis, Giorgio Fagiolo, Lucia Tajoli May 2018

Distance-Varying Assortativity And Clustering Of The International Trade Network, Angela Abbate, Luca De Benedictis, Giorgio Fagiolo, Lucia Tajoli

Luca De Benedictis

In this paper we study how the topology of the International Trade Network (ITN) changes in geographical space, and along time. We employ geographical distance between countries in the World to filter the links in the ITN, building a sequence of sub-networks, each one featuring trade links occurring at similar distance. We then test if the assortativity
and clustering of ITN subnetworks changes as distance increases, and we nd that this is indeed the case: distance strongly impacts, in a non-linear way, the topology of the ITN.We show that the ITN is disassortative at long distances while it is assortative …


Predication Of The Sources Of Particulate Polycyclic Aromatic Hydrocarbons In China With Distinctive Characteristics Based On Multivariate Analysis, Ruoyu Wang May 2018

Predication Of The Sources Of Particulate Polycyclic Aromatic Hydrocarbons In China With Distinctive Characteristics Based On Multivariate Analysis, Ruoyu Wang

Ruoyu Wang

Particulate polycyclic aromatic hydrocarbons (PAHs) have the characteristics of high carcinogenicitydegradation resistance, and long-distance transport. It is necessary to determine the critical sources that contribute to PAHs in atmospheric particulatematter (PM), soils, and sediments. In the present study, particulate PAHs were collected from Chinese cooking, biomass combustion, waste incineration, coal combustion, and petroleum combustion in different regions of the Chinese mainland. Through linear regression analysis, the relationships have been investigated between different measurement units, including the mass of particulate PAHs per mass of particle matter, mass of particulate PAHs per volume of …


Exact Confidence Intervals And Rectangles For The Endpoints Of The Uniform Distribution, Iosif Pinelis May 2018

Exact Confidence Intervals And Rectangles For The Endpoints Of The Uniform Distribution, Iosif Pinelis

Iosif Pinelis

No abstract provided.


Status Of The Ucnτ Experiment, Robert W. Pattie Jr. May 2018

Status Of The Ucnτ Experiment, Robert W. Pattie Jr.

Robert W. Pattie Jr.

The neutron is the simplest nuclear system that can be used to probe the structure of the weak interaction and search for physics Beyond the Standard Model. Measurements of neutron lifetime and β-decay correlation coefficients with precisions of 0.02% and 0.1%, respectively, would allow for stringent constraints on new physics. The UCNτ experiment uses an asymmetric magneto-gravitational UCN trap with in situ counting of surviving neutrons to measure the neutron lifetime, \tau_n=877.7(0.7)_{stat}(+0.3 /-0.1 )_{sys}s. I will discuss the recent result from UCNτ, the status of ongoing data collection and analysis, and the path toward a 0.2 …


An Investigation Into Trust And Security In The Mandatory And Imposed Use Of Financial Icts Upon Older People, David Michael Cook May 2018

An Investigation Into Trust And Security In The Mandatory And Imposed Use Of Financial Icts Upon Older People, David Michael Cook

Dr. David M Cook

Care needs to be taken to reduce the number of people who are fearful and mistrustful of using ICT where that usage is forced upon them without choice or alternative. The growing incidence of mandatory and imposed online systems can result in confusion, misuse, fear, and rejection by people with only rudimentary ICT skills. A cohort where a high percentage of such people occur is older people, defined in this study as people over the age of 60 Examples of compulsory ICT interactions include some banks limiting bank statement access through online rather than paper-based options. Other examples include the …


Space Operations In The Suborbital Space Flight Simulator And Mission Control Center: Lessons Learned With Xcor Lynx, Pedro Llanos, Christopher Nguyen, David Williams, Kim O. Chambers Ph.D., Erik Seedhouse, Robert Davidson May 2018

Space Operations In The Suborbital Space Flight Simulator And Mission Control Center: Lessons Learned With Xcor Lynx, Pedro Llanos, Christopher Nguyen, David Williams, Kim O. Chambers Ph.D., Erik Seedhouse, Robert Davidson

Pedro J. Llanos (www.AstronauticsLlanos.com)

This study was conducted to better understand the performance of the XCOR Lynx vehicle. Because the Lynx development was halted, the best knowledge of vehicle dynamics can only be found through simulator flights. X-Plane 10 was chosen for its robust applications and accurate portrayal of dynamics on a vehicle in flight. The Suborbital Space Flight Simulator (SSFS) and Mission Control Center (MCC) were brought to the Applied Aviation Sciences department in fall 2015 at Embry-Riddle Aeronautical University, Daytona Beach campus. This academic and research tool is a department asset capable of providing multiple fields of data about suborbital simulated flights. …


Heteroclinic And Homoclinic Connections Between The Sun-Earth Triangular Points And Quasi-Satellite Orbits For Solar Observations, Pedro J. Llanos, Gerald R. Hintz, Martin W. Lo, James K. Miller May 2018

Heteroclinic And Homoclinic Connections Between The Sun-Earth Triangular Points And Quasi-Satellite Orbits For Solar Observations, Pedro J. Llanos, Gerald R. Hintz, Martin W. Lo, James K. Miller

Pedro J. Llanos (www.AstronauticsLlanos.com)

Investigation of new orbit geometries exhibits a very attractive behavior for a spacecraft to monitor space weather coming from the Sun. Several orbit transfer mechanisms are analyzed as potential alternatives to monitor solar activity such as a sub-solar orbit or quasi-satellite orbit and short and long heteroclinic and homoclinic connections between the triangular points L4 and L5 and the collinear point L3 of the CRTBP (circular restricted three-body problem) in the Sun-Earth system. These trajectories could serve as channels through where material can be transported from L5 to L3 by performing small maneuvers at the departure of the Trojan orbit. …


Search For Dark Matter Decay Of The Free Neutron From The Ucna Experiment: N → Χ + E^+E^−, Xiaohui Sun, Edith Adamek, Bruno Allgeier, Matthias A. Blatnik, Thomas J. Bowles, Leah J. Broussard, Matthew A. Brown, Richard Carr, Steven M. Clayton, Chris Cude-Woods, Sonja Currie, Eric B. Dees, Xingxing Ding, Bradley W. Filippone, A. Bello García, Peter Geltenbort, Salajeghe Hasan, Kevin P. Hickerson, J. Todd Hoagland, R. Hong, Gary E. Hogan, Anthony T. Holley, Takeyasu M. Ito, Amanda L. Knecht, Chao-Yu Liu, Jingyang Liu, María Makela, Russel Mammei, J. W. Martin, Dan Melconian, Michael P. Mendenhall, Stephen D. Moore, Charles L. Morris, Sushil Nepal, N. Vahedi Nouri, Robert W. Pattie Jr., A. Pérez Galván, David G. Phillips, Richard H. Picker, Margaret L. Pitt, Blakely A. Plaster, Jana C. Ramsey, R. Barreto Rios, Daniel J. Salvat, Andy Saunders, Walter Sondheim, S. Sjue, Steven Slutsky, Charles Swank, Gyani Swift, E. Tatar, R. Bruce Vogelaar, Brittany Vorndick, Z. Wang, Wanchun Wei, J. Wexler, T. Womack, Christopher Wrede, Andrew R. Young, B. A. Zeck May 2018

Search For Dark Matter Decay Of The Free Neutron From The Ucna Experiment: N → Χ + E^+E^−, Xiaohui Sun, Edith Adamek, Bruno Allgeier, Matthias A. Blatnik, Thomas J. Bowles, Leah J. Broussard, Matthew A. Brown, Richard Carr, Steven M. Clayton, Chris Cude-Woods, Sonja Currie, Eric B. Dees, Xingxing Ding, Bradley W. Filippone, A. Bello García, Peter Geltenbort, Salajeghe Hasan, Kevin P. Hickerson, J. Todd Hoagland, R. Hong, Gary E. Hogan, Anthony T. Holley, Takeyasu M. Ito, Amanda L. Knecht, Chao-Yu Liu, Jingyang Liu, María Makela, Russel Mammei, J. W. Martin, Dan Melconian, Michael P. Mendenhall, Stephen D. Moore, Charles L. Morris, Sushil Nepal, N. Vahedi Nouri, Robert W. Pattie Jr., A. Pérez Galván, David G. Phillips, Richard H. Picker, Margaret L. Pitt, Blakely A. Plaster, Jana C. Ramsey, R. Barreto Rios, Daniel J. Salvat, Andy Saunders, Walter Sondheim, S. Sjue, Steven Slutsky, Charles Swank, Gyani Swift, E. Tatar, R. Bruce Vogelaar, Brittany Vorndick, Z. Wang, Wanchun Wei, J. Wexler, T. Womack, Christopher Wrede, Andrew R. Young, B. A. Zeck

Robert W. Pattie Jr.

It has been proposed recently that a previously unobserved neutron decay branch to a dark matter particle (χ) could account for the discrepancy in the neutron lifetime observed in experiments that use two different measurement techniques. One of the possible final states discussed includes a single χalong with an e+e pair. We use data from the UCNA (Ultracold Neutron Asymmetry) experiment to set limits on this decay channel. Coincident electron-like events are detected with ∼4π acceptance using a pair of detectors that observe a volume of stored ultracold neutrons. The summed kinetic energy …


High Consequence Scenarios For North Korean Atmospheric Nuclear Tests With Policy Recommendations For The U.S. Government, Thomas S. Popik, Jordan T. Kearns, George H. Baker Iii, Henry F. Cooper, William R. Harris May 2018

High Consequence Scenarios For North Korean Atmospheric Nuclear Tests With Policy Recommendations For The U.S. Government, Thomas S. Popik, Jordan T. Kearns, George H. Baker Iii, Henry F. Cooper, William R. Harris

George H Baker

The government of North Korea has declared high-altitude EMP-capability to be a “strategic goal” and has also threatened an atmospheric test of a hydrogen bomb. Atmospheric nuclear tests have the potential to cripple satellites and the undersea cable networks critical to communication, and navigation necessary for trans-Pacific trade among the U.S., China, and other nations. When a nuclear warhead is detonated at high altitude, a series of electromagnetic pulses radiate downward within the line of sight of the blast. These pulses can disable equipment with miniature electronics and long conductors. Electric grid controls and transmission systems are especially vulnerable. Intense …


Measurement Of The Neutron Lifetime Using A Magneto-Gravitational Trap And In Situ Detection, Robert W. Pattie Jr., Nathan B. Callahan, Chris Cude-Woods, Edith R. Adamek, Leah J. Broussard, Stephen M. Clayton, Scott A. Currie, Eric B. Dees, Xiaoping Ding, Egbert M. Engel, D. E. Fellers, William Fox, Peter Geltenbort, Kevin P. Hickerson, Mark A. Hoffbauer, Anthony T. Holley, A. Komives, Chen Liu, S. W. T. Macdonald, Mark Makela, Christopher L. Morris, Joseph D. Ortiz, John C. Ramsey, Daniel J. Salvat, Alexander Saunders, Susan J. Seestrom, E. I. Sharapov, S. K. Sjue, Zebo Tang, J. Vanderwerp, Bruce Vogelaar, P. L. Walstrom, Zhehui Wang, Wei Wei, H. L. Weaver, Judith W. Wexler, Tanner L. Womack, Andrew R. Young, B. A. Zeck May 2018

Measurement Of The Neutron Lifetime Using A Magneto-Gravitational Trap And In Situ Detection, Robert W. Pattie Jr., Nathan B. Callahan, Chris Cude-Woods, Edith R. Adamek, Leah J. Broussard, Stephen M. Clayton, Scott A. Currie, Eric B. Dees, Xiaoping Ding, Egbert M. Engel, D. E. Fellers, William Fox, Peter Geltenbort, Kevin P. Hickerson, Mark A. Hoffbauer, Anthony T. Holley, A. Komives, Chen Liu, S. W. T. Macdonald, Mark Makela, Christopher L. Morris, Joseph D. Ortiz, John C. Ramsey, Daniel J. Salvat, Alexander Saunders, Susan J. Seestrom, E. I. Sharapov, S. K. Sjue, Zebo Tang, J. Vanderwerp, Bruce Vogelaar, P. L. Walstrom, Zhehui Wang, Wei Wei, H. L. Weaver, Judith W. Wexler, Tanner L. Womack, Andrew R. Young, B. A. Zeck

Robert W. Pattie Jr.

The precise value of the mean neutron lifetime, tn, plays an important role in nuclear and particle physics and cosmology. It is used to predict the ratio of protons to helium atoms in the primordial universe and to search for physics beyond the Standard Model of particle physics. We eliminated loss mechanisms present in previous trap experiments by levitating polarized ultracold neutrons above the surface of an asymmetric storage trap using a repulsive magnetic field gradient so that the stored neutrons do not interact with material trap walls. As a result of this approach and the use of an in …


Rainbow Matchings And Hamilton Cycles In Random Graphs, Deepak Bal, Alan Frieze May 2018

Rainbow Matchings And Hamilton Cycles In Random Graphs, Deepak Bal, Alan Frieze

Deepak Bal

Let HPn,m,k be drawn uniformly from all m-edge, k-uniform, k-partite hypergraphs where each part of the partition is a disjoint copy of [n]. We let HP(κ) n,m,k be an edge colored version, where we color each edge randomly from one of κ colors. We show that if κ = n and m = Kn log n where K is sufficiently large then w.h.p. there is a rainbow colored perfect matching. I.e. a perfect matching in which every edge has a different color. We also show that if n is even and m = Kn log n where K is sufficiently …


The T-Tone Chromatic Number Of Random Graphs, Deepak Bal, Patrick Bennett, Andrzej Dudek, Alan Frieze May 2018

The T-Tone Chromatic Number Of Random Graphs, Deepak Bal, Patrick Bennett, Andrzej Dudek, Alan Frieze

Deepak Bal

A proper 2-tone k-coloring of a graph is a labeling of the vertices with elements from ([k]2) such that adjacent vertices receive disjoint labels and vertices distance 2 apart receive distinct labels. The 2-tone chromatic number of a graph G, denoted τ 2(G) is the smallest k such thatG admits a proper 2-tone k coloring. In this paper, we prove that w.h.p. for p≥Cn−1/4ln9/4n,τ2(Gn,p)=(2+o(1))χ(Gn,p) where χ represents the ordinary chromatic number. For sparse random graphs with p = c/n, c constant, we prove that τ2(Gn,p)=⌈(8Δ+1−−−−−−√+5)/2 where Δ represents the maximum degree. For …


A Greedy Algorithm For Finding A Large 2-Matching On A Random Cubic Graph, Deepak Bal, Patrick Bennett, Tom Bohman, Alan Frieze May 2018

A Greedy Algorithm For Finding A Large 2-Matching On A Random Cubic Graph, Deepak Bal, Patrick Bennett, Tom Bohman, Alan Frieze

Deepak Bal

A 2-matching of a graph G is a spanning subgraph with maximum degree two. The size of a 2-matching U is the number of edges in U and this is at least $n-\k(U)$ where n is the number of vertices of G and $\k$ denotes the number of components. In this paper, we analyze the performance of a greedy algorithm \textsc{2greedy} for finding a large 2-matching on a random 3-regular graph. We prove that with high probability, the algorithm outputs a 2-matching U with$\k(U) = \tilde{\Theta}\of{n^{1/5}}$.


Power Of K Choices And Rainbow Spanning Trees In Random Graphs, Deepak Bal, Patrick Bennett, Alan Frieze, Pawel Pralat May 2018

Power Of K Choices And Rainbow Spanning Trees In Random Graphs, Deepak Bal, Patrick Bennett, Alan Frieze, Pawel Pralat

Deepak Bal

We consider the Erdős-Rényi random graph process, which is a stochastic process that starts with nvertices and no edges, and at each step adds one new edge chosen uniformly at random from the set of missing edges. Let G(n,m) be a graph with m edges obtained after m steps of this process. Each edge ei (i=1,2,…,m) of G(n,m) independently chooses precisely k∈N colours, uniformly at random, from a given set of n−1 colours (one may view ei as a multi-edge). We stop the process prematurely at time M when the following two events hold: G(n,M) is connected and every colour …


Packing Tree Factors In Random And Pseudo-Random Graphs, Deepak Bal, Alan Frieze, Michael Krivelevich, Po-Shen Loh May 2018

Packing Tree Factors In Random And Pseudo-Random Graphs, Deepak Bal, Alan Frieze, Michael Krivelevich, Po-Shen Loh

Deepak Bal

For a fixed graph H with t vertices, an H-factor of a graph G with n vertices, where t divides n, is a collection of vertex disjoint (not necessarily induced) copies of H in G covering all vertices of G. We prove that for a fixed tree T on t vertices and ϵ>0, the random graph Gn,p, with n a multiple of t, with high probability contains a family of edge-disjoint T-factors covering all but an ϵ-fraction of its edges, as long as ϵ4np≫log2n. Assuming stronger divisibility conditions, the edge probability can be taken down to p>Clognn. A …


Rainbow Arborescence In Random Digraphs, Deepak Bal, Patrick Bennett, Colin Cooper, Alan Frieze, Pawel Pralat May 2018

Rainbow Arborescence In Random Digraphs, Deepak Bal, Patrick Bennett, Colin Cooper, Alan Frieze, Pawel Pralat

Deepak Bal

We consider the Erd˝os-R´enyi random directed graph process, which is a stochastic process that starts with n vertices and no edges, and at each step adds one new directed edge chosen uniformly at random from the set of missing edges. Let D(n, m) be a graph with m edges obtained after m steps of this process. Each edge ei (i = 1, 2, . . . , m) of D(n, m) independently chooses a colour, taken uniformly at random from a given set of n(1 + O(log log n/ log n)) = n(1 + o(1)) colours. We stop the process …


Packing Tight Hamilton Cycles In Uniform Hypergraphs, Deepak Bal, Alan Frieze May 2018

Packing Tight Hamilton Cycles In Uniform Hypergraphs, Deepak Bal, Alan Frieze

Deepak Bal

We say that a k-uniform hypergraph C is a Hamilton cycle of type ℓ, for some 1 ≤ ℓ ≤ k, if there exists a cyclic ordering of the vertices of C such that every edge consists of k consecutive vertices and for every pair of consecutive edges Ei−1, Ei in C (in the natural ordering of the edges) we have |Ei−1 \ Ei | = ℓ. We define a class of (ε, p)-regular hypergraphs, that includes random hypergraphs, for which we can prove the existence of a decomposition of almost all edges into type ℓ Hamilton cycles, where ℓ < k/2.


Antedependence Models For Skewed Continuous Longitudinal Data, Shu-Ching Chang May 2018

Antedependence Models For Skewed Continuous Longitudinal Data, Shu-Ching Chang

Shu-Ching Chang, PhD, MS

This thesis explores the problems of fitting antedependence (AD) models and partial antecorrelation (PAC) models to continuous non-Gaussian longitudinal data. AD models impose certain conditional independence relations among the measurements within each subject, while PAC models characterize the partial correlation relations. The models are parsimonious and useful for data exhibiting time-dependent correlations.

Since the relation of conditional independence among variables is rather restrictive, we first consider an autoregressively characterized PAC model with independent asymmetric Laplace (ALD) innovations and prove that this model is an AD model. The ALD distribution previously has been applied to quantile regression and has shown promise …


“Fkamathamnareshbabusp18”.Pdf, Nareshbabu Kamatham May 2018

“Fkamathamnareshbabusp18”.Pdf, Nareshbabu Kamatham

Nareshbabu Kamatham

No abstract provided.


Leih-Shan Yeung(Alex) Thesis-Final Version Accept W Signature-03may2018.Pdf, Leih-Shan Yeung, Leih-Shan Yeung May 2018

Leih-Shan Yeung(Alex) Thesis-Final Version Accept W Signature-03may2018.Pdf, Leih-Shan Yeung, Leih-Shan Yeung

Leih-Shan Yeung

this research is to explore a more general column categorization method using the test attributes in alignment with the common mobile phase components. As we know, the primary driving force for solute retention on a reversed-phase surface is hydrophobic interaction, thus hydrophobicity of the column will directly affect the analyte retention. This research describes a method to determine the column hydrophobicity by the ratio of adsorbed acetonitrile and methanol to water on the column surface using excess adsorption isotherm estimation. An excess adsorption isotherm for a binary mobile phase system represents a competitive interaction of both solvent components with the …


Scrumtutor: A Web-Based Interactive Tutorial For Scrum Software Development, Sindhura Potineni, Srividya K. Bansal, Ashish Amresh Apr 2018

Scrumtutor: A Web-Based Interactive Tutorial For Scrum Software Development, Sindhura Potineni, Srividya K. Bansal, Ashish Amresh

Ashish Amresh

In a traditional software engineering class, students are typically engaged in theoretical lectures followed by homework assignments or a project. Use of hands-on training and laboratory activities using realworld projects is more likely to produce students with a higher level of achievement and more confidence in the course material. If every topic or technique introduced in the course has a corresponding hands-on activity that demonstrates an application or use of the concept in the industry, students better understand the need for the technique and the learning environment is more interactive, engaging, and interesting to students. This paper presents a project …