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Physical Sciences and Mathematics Commons™

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2014

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Articles 11551 - 11580 of 12299

Full-Text Articles in Physical Sciences and Mathematics

Simulation Of The Sampling Distribution Of The Mean Can Mislead, Ann E. Watkins, Anna E. Bargagliotti, Christine Franklin Jan 2014

Simulation Of The Sampling Distribution Of The Mean Can Mislead, Ann E. Watkins, Anna E. Bargagliotti, Christine Franklin

Mathematics, Statistics and Data Science Faculty Works

Although the use of simulation to teach the sampling distribution of the mean is meant to provide students with sound conceptual understanding, it may lead them astray. We discuss a misunderstanding that can be introduced or reinforced when students who intuitively understand that “bigger samples are better” conduct a simulation to explore the effect of sample size on the properties of the sampling distribution of the mean. From observing the patterns in a typical series of simulated sampling distributions constructed with increasing sample sizes, students reasonably—but incorrectly—conclude that, as the sample size, n, increases, the mean of the (exact) sampling …

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Polarization Of Bi2te3 Thin Film In A Floating-Gate Capacitor Structure, Hui Yuan, Kai Zhang, Haitao Li, Hao Zhu, John E. Bonevich, Helmut Baumgart, Curt A. Richter, Qiliang Li Jan 2014

Polarization Of Bi2te3 Thin Film In A Floating-Gate Capacitor Structure, Hui Yuan, Kai Zhang, Haitao Li, Hao Zhu, John E. Bonevich, Helmut Baumgart, Curt A. Richter, Qiliang Li

Electrical & Computer Engineering Faculty Publications

Metal-Oxide-Semiconductor (MOS) capacitors with Bi2Te3 thin film sandwiched and embedded inside the oxide layer have been fabricated and studied. The capacitors exhibit ferroelectric-like hysteresis which is a result of the robust, reversible polarization of the Bi2Te3 thin film while the gate voltage sweeps. The temperature-dependent capacitance measurement indicates that the activation energy is about 0.33 eV for separating the electron and hole pairs in the bulk of Bi2Te3, and driving them to either the top or bottom surface of the thin film. Because of the fast polarization speed, potentially excellent …

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Principles And Properties Of Eukaryotic Mrnps, Sarah F. Mitchell Jan 2014

Principles And Properties Of Eukaryotic Mrnps, Sarah F. Mitchell

Chemistry and Biochemistry Faculty Works

The proper processing, export, localization, translation, and degradation of mRNAs are necessary for regulation of gene expression. These processes are controlled by mRNA-specific regulatory proteins, noncoding RNAs, and core machineries common to most mRNAs. These factors bind the mRNA in large complexes known as messenger ribonucleoprotein particles (mRNPs). Herein, we review the components of mRNPs, how they assemble and rearrange, and how mRNP composition differentially affects mRNA biogenesis, function, and degradation. We also describe how properties of the mRNP "interactome" lead to emergent principles affecting the control of gene expression.

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Identification And Characterization Of Functionally Critical, Conserved Motifs In The Internal Repeats And N-Terminal Domain Of Yeast Translation Initiation Factor 4b (Yeif4b), Sarah F. Mitchell Jan 2014

Identification And Characterization Of Functionally Critical, Conserved Motifs In The Internal Repeats And N-Terminal Domain Of Yeast Translation Initiation Factor 4b (Yeif4b), Sarah F. Mitchell

Chemistry and Biochemistry Faculty Works

EIF4B has been implicated in attachment of the 43 S preinitiation complex (PIC) to mRNAs and scanning to the start codon. We recently determined that the internal seven repeats (of ∼26 amino acids each) of Saccharomyces cerevisiae eIF4B (yeIF4B) compose the region most critically required to enhance mRNA recruitment by 43 S PICs in vitro and stimulate general translation initiation in yeast. Moreover, although the N-terminal domain (NTD) of yeIF4B contributes to these activities, the RNA recognition motif is dispensable. We have now determined that only two of the seven internal repeats are sufficient for wildtype (WT) yeIF4B function in …

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Structure And Dynamics Of The Hiv-1 Frameshift Element Rna, Kathryn Mouzakis Jan 2014

Structure And Dynamics Of The Hiv-1 Frameshift Element Rna, Kathryn Mouzakis

Chemistry and Biochemistry Faculty Works

The HIV-1 ribosomal frameshift element is highly structured, regulates translation of all virally encoded enzymes, and is a promising therapeutic target. The prior model for this motif contains two helices separated by a three-nucleotide bulge. Modifications to this model were suggested by SHAPE chemical probing of an entire HIV-1 RNA genome. Novel features of the SHAPE-directed model include alternate helical conformations and a larger, more complex structure. These structural elements also support the presence of a secondary frameshift site within the frameshift domain. Here, we use oligonucleotide-directed structure perturbation, probing in the presence of formamide, and in-virion experiments to examine …

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An Incremental Reseeding Strategy For Clustering, Xavier Bresson, Huiyi Hu, Thomas Laurent, Arthur Szlam, James Von Brecht Jan 2014

An Incremental Reseeding Strategy For Clustering, Xavier Bresson, Huiyi Hu, Thomas Laurent, Arthur Szlam, James Von Brecht

Mathematics, Statistics and Data Science Faculty Works

In this work we propose a simple and easily parallelizable algorithm for multiway graph partitioning. The algorithm alternates between three basic components: diffusing seed vertices over the graph, thresholding the diffused seeds, and then randomly reseeding the thresholded clusters. We demonstrate experimentally that the proper combination of these ingredients leads to an algorithm that achieves state-of-the-art performance in terms of cluster purity on standard benchmarks datasets. Moreover, the algorithm runs an order of magnitude faster than the other algorithms that achieve comparable results in terms of accuracy. We also describe a coarsen, cluster and refine approach similar to GRACLUS and …

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Complete Bipartite Graphs Whose Topological Symmetry Groups Are Polyhedral, Blake Mellor Jan 2014

Complete Bipartite Graphs Whose Topological Symmetry Groups Are Polyhedral, Blake Mellor

Mathematics, Statistics and Data Science Faculty Works

We determine for which n, the complete bipartite graph Kn,n has an embedding in S3 whose topological symmetry group is isomorphic to one of the polyhedral groups: A4, A5, or S4.

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La Formazione Degli Insegnanti: Una Necessità Non Più Rinviabile, Anna E. Bargagliotti Jan 2014

La Formazione Degli Insegnanti: Una Necessità Non Più Rinviabile, Anna E. Bargagliotti

Mathematics, Statistics and Data Science Faculty Works

No abstract provided.

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Robust Noise Attenuation Under Stochastic Noises And Worst-Case Unmodelled Dynamics, Araz Hashemi, Ben G. Fitzpatrick, Le Yi Wang, George Yin Jan 2014

Robust Noise Attenuation Under Stochastic Noises And Worst-Case Unmodelled Dynamics, Araz Hashemi, Ben G. Fitzpatrick, Le Yi Wang, George Yin

Mathematics, Statistics and Data Science Faculty Works

This paper investigates noise attenuation problems for systems with unmodelled dynamics and unknown noise characteristics. A unique methodology is introduced that employs signal estimation in one phase, followed by control design for noise rejection. The methodology enjoys certain advantages in its simple control design process, accommodation of unmodelled dynamics, and non-conservative noise rejection performance. Under mild information on unmodelled dynamics, we first derive robust performance bounds on noise attenuation with respect to unmodelled dynamics without noise estimation errors. Then more general results are presented for systems that are subject to both stochastic signal estimation errors and unmodelled dynamics. Examples are …

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Mathematical Methods Applied To Digital Image Processing, Yi-Hung Liu, Chung Hao Chen, Paul C.P. Chao Jan 2014

Mathematical Methods Applied To Digital Image Processing, Yi-Hung Liu, Chung Hao Chen, Paul C.P. Chao

Electrical & Computer Engineering Faculty Publications

Introduction: Digital image processing (DIP) is an important research area since it spans a variety of applications. Although over the past few decades there has been a rapid rise in this field, there still remain issues to address. Examples include image coding, image restoration, 3D image processing, feature extraction and analysis, moving object detection, and face recognition. To deal with these issues, the use of sophisticated and robust mathematical algorithms plays a crucial role. The aim of this special issue is to provide an opportunity for researchers to publish their latest theoretical and technological achievements in mathematical methods and their …

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Emergence Of Algal Blooms: The Effects Of Short-Term Variability In Water Quality On Phytoplankton Abundance, Diversity, And Community Composition In A Tidal Estuary, Todd A. Egerton, Ryan E. Morse, Harold G. Marshall, Margaret R. Mulholland Jan 2014

Emergence Of Algal Blooms: The Effects Of Short-Term Variability In Water Quality On Phytoplankton Abundance, Diversity, And Community Composition In A Tidal Estuary, Todd A. Egerton, Ryan E. Morse, Harold G. Marshall, Margaret R. Mulholland

OES Faculty Publications

Algal blooms are dynamic phenomena, often attributed to environmental parameters that vary on short timescales (e.g., hours to days). Phytoplankton monitoring programs are largely designed to examine long-term trends and interannual variability. In order to better understand and evaluate the relationships between water quality variables and the genesis of algal blooms, daily samples were collected over a 34 day period in the eutrophic Lafayette River, a tidal tributary within Chesapeake Bay's estuarine complex, during spring 2006. During this period two distinct algal blooms occurred; the first was a cryptomonad bloom and this was followed by a bloom of the mixotrophic …

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A Coupled Geochemical And Biogeochemical Approach To Characterize The Bioreactivity Of Dissolved Organic Matter From A Headwater Stream, Rachel L. Sleighter, Rose M. Cory, Louis A. Kaplan, Hussain A.N. Abdulla, Patrick G. Hatcher Jan 2014

A Coupled Geochemical And Biogeochemical Approach To Characterize The Bioreactivity Of Dissolved Organic Matter From A Headwater Stream, Rachel L. Sleighter, Rose M. Cory, Louis A. Kaplan, Hussain A.N. Abdulla, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

The bioreactivity or susceptibility of dissolved organic matter (DOM) to microbial degradation in streams and rivers is of critical importance to global change studies, but a comprehensive understanding of DOM bioreactivity has been elusive due, in part, to the stunningly diverse assemblages of organic molecules within DOM. We approach this problem by employing a range of techniques to characterize DOM as it flows through biofilm reactors: dissolved organic carbon (DOC) concentrations, excitation emission matrix spectroscopy (EEMs), and ultrahigh resolution mass spectrometry. The EEMs and mass spectral data were analyzed using a combination of multivariate statistical approaches. We found that 45% …

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Efficient Frameworks For Lifetime Maximization In Tree Based Sensor Networks, Sk Kajal Arefin Imon Jan 2014

Efficient Frameworks For Lifetime Maximization In Tree Based Sensor Networks, Sk Kajal Arefin Imon

Computer Science and Engineering Dissertations

In most wireless sensor network (WSN) applications, data are typically gathered by the sensor nodes and reported to a data collection point, called the sink. In order to support such data collection, a tree structure rooted at the sink is usually defined. Based on different aspects, including the actual WSN topology and the available energy budget, the energy consumption of nodes belonging to different paths in the data collection tree may vary significantly. This affects the overall network lifetime, defined in terms of when the first node in the network runs out of energy. In this thesis, we address the …

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Modified Seed Growth Of Iron Oxide Nanoparticles In Benzyl Alcohol: Magnetic Nanoparticles For Radio Frequency Hyperthermia Treatment Of Cancer, Stanley E. Gilliland Iii Jan 2014

Modified Seed Growth Of Iron Oxide Nanoparticles In Benzyl Alcohol: Magnetic Nanoparticles For Radio Frequency Hyperthermia Treatment Of Cancer, Stanley E. Gilliland Iii

Theses and Dissertations

Iron oxide nanoparticles have received sustained interest for biomedical applications as synthetic approaches are continually developed for precise control of nanoparticle properties. This thesis presents an investigation of parameters in the benzyl alcohol synthesis of iron oxide nanoparticles. A modified seed growth method was designed for obtaining optimal nanoparticle properties for magnetic fluid hyperthermia. With a one or two addition process, iron oxide nanoparticles were produced with crystallite sizes ranging from 5-20 nm using only benzyl alcohol and iron precursor. The effects of reaction environment, temperature, concentration, and modified seed growth parameters were investigated to obtain precise control over properties …

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Building Community Resilience And Developing Adaptive Capabilities To Cope With Sea Level Rise In Hampton Roads And Beyond, Hans-Peter Plag, Ray Toll Jan 2014

Building Community Resilience And Developing Adaptive Capabilities To Cope With Sea Level Rise In Hampton Roads And Beyond, Hans-Peter Plag, Ray Toll

Presentations, Lectures, Posters, Reports

No abstract provided.

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Integrating People And Place: A Density-Based Measure For Assessing Accessibility To Opportunities, Mark Horner, Joni A. Downs Jan 2014

Integrating People And Place: A Density-Based Measure For Assessing Accessibility To Opportunities, Mark Horner, Joni A. Downs

School of Geosciences Faculty and Staff Publications

Mobile object analysis is a well-studied area of transportation and geographic information science (GIScience). Mobile objects may include people, animals, or vehicles. Time geography remains a key theoretical framework for understanding mobile objects' movement possibilities. Recent efforts have sought to develop probabilistic methods of time geography by exploring questions of data uncertainty, spatial representation, and other limitations of classical approaches. Along these lines, work has blended time geography and kernel density estimation in order to delineate the probable locations of mobile objects in both continuous and discrete network space. This suite of techniques is known as time geographic density estimation …

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Rejoinder Of “Dynamic Treatment Regimes: Technical Challenges And Applications", Eric B. Laber, Daniel J. Lizotte, Min Qian, William Pelham, Susan A. Murphy Jan 2014

Rejoinder Of “Dynamic Treatment Regimes: Technical Challenges And Applications", Eric B. Laber, Daniel J. Lizotte, Min Qian, William Pelham, Susan A. Murphy

Center for Children and Families Faculty Publications

No abstract provided.

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Dynamic Treatment Regimes: Technical Challenges And Applications, Eric B. Laber, Daniel J. Lizotte, Min Qian, William E. Pelham, Susan A. Murphy Jan 2014

Dynamic Treatment Regimes: Technical Challenges And Applications, Eric B. Laber, Daniel J. Lizotte, Min Qian, William E. Pelham, Susan A. Murphy

Center for Children and Families Faculty Publications

Dynamic treatment regimes are of growing interest across the clinical sciences because these regimes provide one way to operationalize and thus inform sequential personalized clinical decision making. Formally, a dynamic treatment regime is a sequence of decision rules, one per stage of clinical intervention. Each decision rule maps up-to-date patient information to a recommended treatment. We briefly review a variety of approaches for using data to construct the decision rules. We then review a critical inferential challenge that results from nonregularity, which often arises in this area. In particular, nonregularity arises in inference for parameters in the optimal dynamic treatment …

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An Unusual Occurrence Of Arthrophycus Alleghaniensis(?) On The Shawangunk Ridge, Lower Mid-Hudson Valley, New York, Howard R. Feldman, Alexander Bartholomew, Beryl Kahn Jan 2014

An Unusual Occurrence Of Arthrophycus Alleghaniensis(?) On The Shawangunk Ridge, Lower Mid-Hudson Valley, New York, Howard R. Feldman, Alexander Bartholomew, Beryl Kahn

Lander College for Women - The Anna Ruth and Mark Hasten School Publications and Research

The Shawangunk Formation is a medial Silurian conglomerate that crops out from near Rosendale, south through Wurtsboro, New York, High Point State Park and the Delaware Water Gap in New Jersey, and at Lehigh Gap, Pennsylvania after which it continues into Maryland and Virginia. The formation overall is interpreted to primarily represent a braided stream environment with flowage from mountains to the east that arose during the Taconic Orogeny into a basin toward the west. The trace fossil Arthrophycus was found in the upper-middle part of the formation on the Shawangunk Ridge at Mohonk, near New Paltz, New York. Arthrophycus …

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Graph Embedding Discriminative Unsupervised Dimensionality Reduction, Yun Liu Jan 2014

Graph Embedding Discriminative Unsupervised Dimensionality Reduction, Yun Liu

Computer Science and Engineering Theses

In this thesis, a novel graph embedding unsupervised dimensionality reduction method was proposed. Simultaneously, we assigned the adaptive and optimal neighbors on the basis of the projected local distances, thus we developed the dimensionality reduction along with the graph construction. The clustering results could be directly exhibited from the learnt graph which has the explicit block diagonal structure.The analysis of experimental result on different databases also determines that the proposed dimensionality reduction method is superior to other related dimensionality reduction methods, like PCA and LPP. In this study, we use synthetic data and real-world benchmark data sets. Also experimental results …

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A Hmm-Based Prediction Model For Spatio-Temporal Trajectories, Sakthi Kumaran Shanmuganathan Jan 2014

A Hmm-Based Prediction Model For Spatio-Temporal Trajectories, Sakthi Kumaran Shanmuganathan

Computer Science and Engineering Theses

Spatio-temporal trajectories are time series data that represent movement of an object over the time. Hidden Markov Models (HMM), a variant of Markov Models (MM), were first applied at a large scale to speech recognition but have also been used in time series prediction by analyzing trends in historical time series data. In this research, we propose a storm prediction model using a HMM built from overall storm trajectories derived from raw rainfall data. This HMM is built by assuming the states are associated with clusters created by clustering the locations of each storm from the overall storm trajectories. Then …

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Improving Tor Performance By Modifying Path Selection, Mehrdad Amirabadi Jan 2014

Improving Tor Performance By Modifying Path Selection, Mehrdad Amirabadi

Computer Science and Engineering Theses

Tor is a popular volunteer-based overlay network that provides anonymity andprivacy for Internet users. Using the Onion Proxy (OP) client, users connect to anetwork of Onion Routers (ORs) and send their traffic through an encrypted path ofthree ORs. One of the main problems of the Tor network is its slow performance, anda key cause of this is the Tor path selection algorithm. In Tor, ORs are selected basedprimarily on their bandwidth. In this work, we improve on the Tor path selectionalgorithm by proposing a new algorithm that besides bandwidth, uses distance as afactor to help reduce propagation delay. In our …

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Linking Entity Profiles, Ramesh Venkataraman Jan 2014

Linking Entity Profiles, Ramesh Venkataraman

Computer Science and Engineering Theses

Entity linking allows one to have collections of data from multiple sources as a global dataset and then query those data. Entity linking allows us to do knowledge discovery on this global dataset which might result in the discovery of some interesting facts and information. Microsoft Academic Search (MAS) is a free public search engine for academic papers and contains the bibliographic information for papers published in journals, conference proceedings and respective citations. As of February 2014, it has indexed over 40 million publications and 20 million authors. LinkedIn is a social networking service used for professional networking. LinkedIn has …

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Estimation Myopia: Tinkering With Perception In Software Estimation And Placebo Estimation In Edw, Hazem Hasan Yassin Jan 2014

Estimation Myopia: Tinkering With Perception In Software Estimation And Placebo Estimation In Edw, Hazem Hasan Yassin

Computer Science and Engineering Theses

The goal of this study is to explore an effective way to provide timely and accurate size estimates for software and for an enterprise data warehouse (EDW). Several research papers attempt to adapt function point (FP) analysis to EDW, but there is not much research in comprehensive techniques to estimate large EDW projects. Despite the generality of FP, it is challenging to employ in an EDW environment. This thesis describes such a technique. Additionally, the thesis provides an overview of general estimating approaches, techniques, models, and tools.This work presents a software tool that is a custom built estimation utility that …

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A Method To Evade Keyword Based Censorship, Ritu R. Patil Jan 2014

A Method To Evade Keyword Based Censorship, Ritu R. Patil

Computer Science and Engineering Theses

Many countries block the content of web pages which are deemed against the morals, religious rules or policies set by government or organization. Countries like China block the post which is against their government interest. Germany blocks contents related to Neo-Nazi group. Most of these web pages are subjected to IP address blocking, DNS poisoning and keyword based filtering. We mainly focus on keyword based filtering as it is fine grained filtering technique where the contents of web pages are filtered using blacklisting. So with increase in surveillance over network, arms race for circumvention techniques has also increased. We propose …

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A Cloud Based Automated Anomaly Detection Framework, Prathibha Datta Kumar Jan 2014

A Cloud Based Automated Anomaly Detection Framework, Prathibha Datta Kumar

Computer Science and Engineering Theses

A machine-to-machine (M2M) communications network hosts millions of heterogeneous devices such as for vehicle tracking, medical services, and home automation and security services. These devices exchange thousands of messages over cellular networks. These messages are Signaling System No. 7 (SS7) messages of various types like authentication, mobility management, and many more, resulting in tera bytes of SS7 signaling traffic data over a period of days. The data generated is diverse, depending on several factors like device activity, hardware manufacturers, and radio / tower interaction. This inherent diversity makes anomaly detection in a M2M network challenging. With millions of messages to …

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Design And Development Of Scalable Solar Powered Water Purification Systems For Developing Nations, Shavin Pinto Jan 2014

Design And Development Of Scalable Solar Powered Water Purification Systems For Developing Nations, Shavin Pinto

Doctoral Dissertations and Master's Theses

This thesis presents the design and development of solar powered water purification systems. The systems were designed to meet specific customer requirements that were established from the experiences gained after the installation of five water purification systems in various Haitian communities. The systems are scalable and are able to supply 10,000-20,000 gallons of clean drinking water per day. The design consists of a three-stage filtration system with a disc-type sediment filter, a 0.1 micron ultrafiltration membrane, and an ultraviolet light for disinfection. The backwash cycle extends the life of the ultrafiltration membrane to 4-7 years before a new filter is …

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Nh-Acidities And Hammett Correlation Of 3-Para Substituted Phenyl-1,2,4-Oxadiazol-5(4h)-Ones And 1,2 \Lambda^43,5-Oxathiadiazole 2-Oxides In Nonaqueous Media, Nedi̇me Dürüst, Yaşar Dürüst, Emi̇ne Özge Gözlükaya Jan 2014

Nh-Acidities And Hammett Correlation Of 3-Para Substituted Phenyl-1,2,4-Oxadiazol-5(4h)-Ones And 1,2 \Lambda^43,5-Oxathiadiazole 2-Oxides In Nonaqueous Media, Nedi̇me Dürüst, Yaşar Dürüst, Emi̇ne Özge Gözlükaya

Turkish Journal of Chemistry

NH acidities of some 3-(p-substitutedphenyl)-1,2,4-oxadiazol-5(4H)-ones and 4-(p-substitutedphenyl)-1,2 \lambda^43,5-oxathiadiazole 2-oxides were determined in methanol by means of potentiometric titration with sodium methoxide. pK_a values of the title compounds calculated from the potentiometric data were interpreted on the basis of structural effects caused by para-substituted groups on the phenyl ring by plotting pK_a values versus Hammett \sigma_p^+ constants, which gave excellent linear correlations.

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Nano-Pipette As Nanoparticle Analyzer And Capillary Gated Ion Transistor, Yauheni Rudzevich Jan 2014

Nano-Pipette As Nanoparticle Analyzer And Capillary Gated Ion Transistor, Yauheni Rudzevich

Electronic Theses and Dissertations

The ability to precisely count inorganic and organic nanoparticles and to measure their size distribution plays a major role in various applications such as drug delivery, nanoparticles counting, and many others. In this work I present a simple resistive pulse method that allows translocations, counting, and measuring the size and velocity distribution of silica nanoparticles and liposomes with diameters from 50 nm to 250 nm. This technique is based on the Coulter counter technique, but has nanometer size pores. It was found that ionic current drops when nanoparticles enter the nanopore of a pulled micropipette, producing a clear translocation signal. …

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Complementary Layered Learning, Sean Mondesire Jan 2014

Complementary Layered Learning, Sean Mondesire

Electronic Theses and Dissertations

Layered learning is a machine learning paradigm used to develop autonomous robotic-based agents by decomposing a complex task into simpler subtasks and learns each sequentially. Although the paradigm continues to have success in multiple domains, performance can be unexpectedly unsatisfactory. Using Boolean-logic problems and autonomous agent navigation, we show poor performance is due to the learner forgetting how to perform earlier learned subtasks too quickly (favoring plasticity) or having difficulty learning new things (favoring stability). We demonstrate that this imbalance can hinder learning so that task performance is no better than that of a suboptimal learning technique, monolithic learning, which …

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