Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

204,807 Full-Text Articles 249,624 Authors 47,230,550 Downloads 403 Institutions

All Articles in Physical Sciences and Mathematics

Faceted Search

204,807 full-text articles. Page 5612 of 5616.

Symmetries Of The Central Vestibular System: Forming Movements For Gravity And A Three-Dimensional World, Gin McCollum, Douglas A. Hanes 2009 Portland State University

Symmetries Of The Central Vestibular System: Forming Movements For Gravity And A Three-Dimensional World, Gin Mccollum, Douglas A. Hanes

Gin McCollum

Intrinsic dynamics of the central vestibular system (CVS) appear to be at least partly determined by the symmetries of its connections. The CVS contributes to whole-body functions such as upright balance and maintenance of gaze direction. These functions coordinate disparate senses (visual, inertial, somatosensory, auditory) and body movements (leg, trunk, head/neck, eye). They are also unified by geometric conditions. Symmetry groups have been found to structure experimentally-recorded pathways of the central vestibular system. When related to geometric conditions in three-dimensional physical space, these symmetry groups make sense as a logical foundation for sensorimotor coordination.


Improving State-Of-The-Art Ocr Through High-Precision Document-Specific Modeling, Andrew Kae, Gary B. Huang, Carl Doersch, Erik G. Learned-Miller 2009 University of Massachusetts - Amherst

Improving State-Of-The-Art Ocr Through High-Precision Document-Specific Modeling, Andrew Kae, Gary B. Huang, Carl Doersch, Erik G. Learned-Miller

Erik G Learned-Miller

Optical character recognition (OCR) remains a difficult problem for noisy documents or documents not scanned at high resolution. Many current approaches rely on stored font models that are vulnerable to cases in which the docu- ment is noisy or is written in a font dissimilar to the stored fonts. We address these problems by learning character models directly from the document itself, rather than using pre-stored font models. This method has had some success in the past, but we are able to achieve substantial improve- ment in error reduction through a novel method for creating nearly error-free document-specifictraining data and ...


Constructing Skill Trees For Reinforcement Learning Agents From Demonstration Trajectories, George Konidaris, Scott Kuindersma, Andrew Barto, Roderic Grupen 2009 University of Massachusetts - Amherst

Constructing Skill Trees For Reinforcement Learning Agents From Demonstration Trajectories, George Konidaris, Scott Kuindersma, Andrew Barto, Roderic Grupen

Roderic Grupen

We introduce CST, an algorithm for constructing skill trees from demonstration trajectories in continuous reinforcement learning domains. CST uses a change-point detection method to segment each trajectory into a skill chain by detecting a change of appropriate abstraction, or that a segment is too complex to model as a single skill. The skill chains from each trajectory are then merged to form a skill tree. We demonstrate that CST constructs an appropriate skill tree that can be further refined through learning in a challenging continuous domain, and that it can be used to segment demonstration trajectories on a mobile manipulator ...


A Closer Look At The Relative Age Effect In The National Hockey League, Vittorio Addona, P. A. Yates 2009 Macalester College

A Closer Look At The Relative Age Effect In The National Hockey League, Vittorio Addona, P. A. Yates

Vittorio Addona

No abstract provided.


Learning From A Single Demonstration: Motion Planning With Skill Segmentation, Scott Kuindersma, George Konidaris, Roderic Grupen, Andrew Barto 2009 University of Massachusetts - Amherst

Learning From A Single Demonstration: Motion Planning With Skill Segmentation, Scott Kuindersma, George Konidaris, Roderic Grupen, Andrew Barto

Roderic Grupen

We propose an approach to control learning from demonstration that first segments demonstration trajectories to identify subgoals to solve the overall task. Using this approach, we show that a mobile robot is able to solve a combined navigation and manipulation task robustly after observing only a single successful trajectory.


The 1905 Einstein Equation In A General Mathematical Analysis Model Of Quasars, Byron E. Bell 2009 DePaul University and Columbia College Chicago

The 1905 Einstein Equation In A General Mathematical Analysis Model Of Quasars, Byron E. Bell

Byron E. Bell

No abstract provided.


Gis @ Ut Libraries, Allison Roberts 2009 University of Tennessee - Knoxville

Gis @ Ut Libraries, Allison Roberts

Allison Roberts

Information handout/poster for GIS services at UT


Joint Feature Selection And Classification For Taxonomic Problems Within Fish Species Complexes, Yixin Chen, Shuqing Huang, Huimin Chen, Henry L. Bart 2009 University of Mississippi

Joint Feature Selection And Classification For Taxonomic Problems Within Fish Species Complexes, Yixin Chen, Shuqing Huang, Huimin Chen, Henry L. Bart

Huimin Chen

It is estimated that 90% of the world’s species are yet to be discovered and described. The main reason for the slow pace of new species description is that the science of taxonomy can be very laborious. To formally describe a new species, taxonomists have to manually gather and analyze data from large numbers of specimens and identify the smallest subset of external body characters that uniquely diagnose the new species as distinct from all its known relatives. In this paper, we present an automated feature selection and classification scheme using logistic regression with controlled false discovery rate to ...


Using Description Logics For The Provision Of Context-Driven Content Adaptation Services, Stephen J.H. Yang, Jia Zhang, Jeff J.S. Huang, Jeffrey J.P. Tsai 2009 Carnegie Mellon University, Silicon Valley

Using Description Logics For The Provision Of Context-Driven Content Adaptation Services, Stephen J.H. Yang, Jia Zhang, Jeff J.S. Huang, Jeffrey J.P. Tsai

Jia Zhang

No abstract provided.


Constraint-Driven Rank-Based Learning For Information Extraction, Sameer Singh, Limin Yao, Sebastian Riedel, Andrew McCallum 2009 University of Massachusetts - Amherst

Constraint-Driven Rank-Based Learning For Information Extraction, Sameer Singh, Limin Yao, Sebastian Riedel, Andrew Mccallum

Andrew McCallum

Most learning algorithms for factor graphs require complete inference over the dataset or an instance before making an update to the parameters. SampleRank is a rank-based learning framework that alleviates this problem by updating the parameters during inference. Most semi-supervised learning algorithms also rely on the complete inference, i.e. calculating expectations or MAP configurations. We extend the SampleRank framework to the semi-supervised learning, avoiding these inference bottlenecks. Different approaches for incorporating unlabeled data and prior knowledge into this framework are explored. We evaluated our method on a standard information extraction dataset. Our approach outperforms the supervised method significantly and ...


Valency Dependence Of Polymorphism And Polyamorphism In Dna-Functionalized Nanoparticles, Wei Dai, Chia Wei Hsu, Francesco Sciortino, Francis W. Starr 2009 Wesleyan University

Valency Dependence Of Polymorphism And Polyamorphism In Dna-Functionalized Nanoparticles, Wei Dai, Chia Wei Hsu, Francesco Sciortino, Francis W. Starr

Francis Starr

Nanoparticles (NP) functionalized with single-stranded DNA (ssDNA) offer a route to custom-designed, self- assembled nanomaterials with potentially unusual properties. The bonding selectivity of DNA guarantees one-to-one binding to form double-stranded DNA (dsDNA), and an appropriate base sequence results in head-to-tail binding linking NP into networks. We explore the phase behavior and structure of a model for NP functionalized with between 3 and 6 short ssDNA through simulations of a coarse-grained molecular model, allowing us to examine both the role of the number of attached strands (valency) and their relative orientations. The NP assemble into networks where the number of NP ...


My Italian Connections: Otto Vogl In Italy, Otto Vogl, Gerald S. Kirshenbaum 2009 University of Massachusetts - Amherst

My Italian Connections: Otto Vogl In Italy, Otto Vogl, Gerald S. Kirshenbaum

Otto Vogl

This document describes Otto Vogl's work in Italy. From 1975, Vogl served for 3 years as the Chairman of the Scientific Advisory Committee to the President Italo Trapasso of the Plastic Materials Company of Montedison SA, Milan, Italy. He was assigned to restructure the research activities and to organize the Research Division. He was responsible for the appointment of DiDrusco as the Vice President of Research and Paolo Galli as the Director of Research at the company’s facilities in Ferrara. Within a year of Vogl’s reorganization of the research organization the high yield catalyst for the polymerization ...


How A Bayesian Might Estimate The Distribution Of Cronbach’S Alpha From Ordinal-Dynamic Scaled Data A Case Study Measuring Nursing Home Resident Quality Of Life, Byron J. Gajewski, Diane K. Boyle, Sarah Thompson 2009 University of Kansas Medical Center

How A Bayesian Might Estimate The Distribution Of Cronbach’S Alpha From Ordinal-Dynamic Scaled Data A Case Study Measuring Nursing Home Resident Quality Of Life, Byron J. Gajewski, Diane K. Boyle, Sarah Thompson

Diane Kay Boyle PhD, RN, FAAN

We demonstrate the utility of a Bayesian based approach for calculating intervals of Cronbach’s alpha from a psychological instrument having ordinal responses with a dynamic scale. A small number of response options on an instrument will cause traditional-based interval estimates to be biased. Ordinal-based solutions are problematic because there is no clear mechanism for handling the dynamic scale. One way to remedy the bias is to adjust with a Bayesian approach. The Bayesian approach adjusts the bias and allows theoretically simple calculations of Cronbach’s alpha and intervals. We demonstrate the calculations of the Bayesian approach while at the ...


Statistical Modeling Of Agatston Score In Multi-Ethnic Study Of Atherosclerosis (Mesa), Anna Liu, S. Ma, J. Carr, W. Post, R. Kronmal 2009 University of Massachusetts - Amherst

Statistical Modeling Of Agatston Score In Multi-Ethnic Study Of Atherosclerosis (Mesa), Anna Liu, S. Ma, J. Carr, W. Post, R. Kronmal

Anna Liu

The MESA (Multi-Ethnic Study of Atherosclerosis) is an ongoing study of the prevalence, risk factors, and progression of subclinical cardiovascular disease in a multi-ethnic cohort. It provides a valuable opportunity to examine the development and progression of CAC (coronary artery calcium), which is an important risk factor for the development of coronary heart disease. In MESA, about half of the CAC scores are zero and the rest are continuously distributed. Such data has been referred to as “zero-inflated data” and may be described using two-part models. Existing two-part model studies have limitations in that they usually consider parametric models only ...


Self-Assembly, Condensation, And Order In Aqueous Lyotropic Chromonic Liquid Crystals Crowded With Additives, Luana Tortora, Heung-Shik Park, Shin-Woong Kang, Victoria Savaryn, Seung-Ho Hong, Konstantine Kaznatcheev, Daniele Finotello, Samuel Sprunt, Satyendra Kumar, Oleg Lavrentovich 2009 Kent State University - Kent Campus

Self-Assembly, Condensation, And Order In Aqueous Lyotropic Chromonic Liquid Crystals Crowded With Additives, Luana Tortora, Heung-Shik Park, Shin-Woong Kang, Victoria Savaryn, Seung-Ho Hong, Konstantine Kaznatcheev, Daniele Finotello, Samuel Sprunt, Satyendra Kumar, Oleg Lavrentovich

Satyendra Kumar

Dense multicomponent systems with macromolecules and small solutes attract a broad research interest as they mimic the molecularly crowded cellular interiors. The additives can condense and align the macromolecules, but they do not change the degree of covalentpolymerization. We chose a lyotropic chromonic liquid crystal with reversibly and non-covalently assembled aggregates as a much softer system, reminiscent of “living polymers”, to demonstrate that small neutral and charged additives cause condensation of aggregates with ensuing orientational and positional ordering and nontrivial morphologies of phase separation, such as tactoids and toroids of the nematic and hexagonal columnar phase coexisting with the isotropic ...


Africa Water Atlas, Stanley Mubako 2009 University of Texas at El Paso

Africa Water Atlas, Stanley Mubako

Stanley Mubako

No abstract provided.


Forced Patterns Near A Turing-Hopf Bifurcation, Chad M. Topaz, Anne Catlla 2009 Macalester College

Forced Patterns Near A Turing-Hopf Bifurcation, Chad M. Topaz, Anne Catlla

Chad M. Topaz

We study time-periodic forcing of spatially-extended patterns near a Turing-Hopf bifurcation point. A symmetry-based normal form analysis yields several predictions, including that (i) weak forcing near the intrinsic Hopf frequency enhances or suppresses the Turing amplitude by an amount that scales quadratically with the forcing strength, and (ii) the strongest effect is seen for forcing that is detuned from the Hopf frequency. To apply our results to specific models, we perform a perturbation analysis on general two-component reaction-diffusion systems, which reveals whether the forcing suppresses or enhances the spatial pattern. For the suppressing case, our results explain features of previous ...


Commissioning And Performance Of The Cms Pixel Tracker With Cosmic Ray, Serguei Chatrchyan Muons, stefan spanier 2009 University of Tennessee - Knoxville

Commissioning And Performance Of The Cms Pixel Tracker With Cosmic Ray, Serguei Chatrchyan Muons, Stefan Spanier

stefan spanier

The pixel detector of the Compact Muon Solenoid experiment consists of three barrel layers and two disks for each endcap. The detector was installed in summer 2008, commissioned with charge injections, and operated in the 3.8 T magnetic field during cosmic ray data taking. This paper reports on the first running experience and presents results on the pixel tracker performance, which are found to be in line with the design specifications of this detector. The transverse impact parameter resolution measured in a sample of high momentum muons is 18 microns.


The Globular Cluster System Of Ngc 1399. V. Dynamics Of The Cluster System Out To 80 Kpc, Y. Schuberth, T. Richtler, M. Hilker, B. Dirsch, L. Bassino, Aaron J. Romanowsky, L. Infante 2009 Universidad Nacional de La Plata

The Globular Cluster System Of Ngc 1399. V. Dynamics Of The Cluster System Out To 80 Kpc, Y. Schuberth, T. Richtler, M. Hilker, B. Dirsch, L. Bassino, Aaron J. Romanowsky, L. Infante

Aaron J. Romanowsky

Globular clusters (GCs) are tracers of the gravitational potential of their host galaxies. Moreover, their kinematic properties may provide clues for understanding the formation of GC systems and their host galaxies. We use the largest set of GC velocities obtained so far of any elliptical galaxy to revise and extend the previous investigations (Richtler et al. 2004) of the dynamics of NGC 1399, the central dominant galaxy of the nearby Fornax cluster of galaxies. The GC velocities are used to study the kinematics, their relation with population properties, and the dark matter halo of NGC 1399. We have obtained 477 ...


Central Dark Matter Content Of Early-Type Galaxies: Scaling Relations And Connections With Star Formation Histories, N. R. Napolitano, Aaron J. Romanowsky, A. J. Tortora 2009 San Jose State University

Central Dark Matter Content Of Early-Type Galaxies: Scaling Relations And Connections With Star Formation Histories, N. R. Napolitano, Aaron J. Romanowsky, A. J. Tortora

Aaron J. Romanowsky

We examine correlations between masses, sizes and star formation histories for a large sample of low-redshift early-type galaxies, using a simple suite of dynamical and stellar population models. We confirm an anticorrelation between the size and stellar age and go on to survey for trends with the central content of dark matter (DM). An average relation between the central DM density and galaxy size of 〈ρDM〉∝R−2eff provides the first clear indication of cuspy DM haloes in these galaxies – akin to standard Λ cold dark matter haloes that have undergone adiabatic contraction. The DM density scales with galaxy mass ...


Digital Commons powered by bepress