Physical Sciences and Mathematics Commons^™

Analysis Of Angular Dependence Of Strong-Field Tunneling Ionization For Co₂, Song-Feng Zhao, Cheng Jin, Anh-Thu Le, T. F. Jiang, C. D. Lin

Physics Faculty Research & Creative Works

We analyzed the discrepancy of the angular dependence of strong-field ionization for CO₂ among the different theoretical calculations and experiments. Using a more accurate ground-state wave function of CO₂ in the asymptotic region, we showed that the accuracy in the earlier tunneling ionization theory of Tong et al. [Phys. Rev. A 66, 033402 (2002)] is much improved. We also concluded that the angular dependence deduced from the experiment of Pavicic [Phys. Rev. Lett. 98, 243001 (2007)] appears to be too narrowly distributed.

Correlated Two-Photon Emission By Transitions Of Dirac-Volkov States In Intense Laser Fields: Qed Predictions, Erik Lotstedt, Ulrich D. Jentschura

Physics Faculty Research & Creative Works

In an intense laser field, an electron may decay by emitting a pair of photons. The two photons emitted during the process, which can be interpreted as a laser-dressed double Compton scattering, remain entangled in a quantifiable way: namely, the so-called concurrence of the photon polarizations gives a gauge-invariant measure of the correlation of the hard gamma rays. We calculate the differential rate and concurrence for a backscattering setup of the electron and photon beam, employing Volkov states and propagators for the electron lines, thus accounting nonperturbatively for the electron-laser interaction. The nonperturbative results are shown to differ significantly compared …

Analysis Of Subgroup Data In Clinical Trials, Kao-Tai Tsai, Karl E. Peace

Biostatistics Faculty Presentations

This conference abstract was published in the Proceedings of the Sixteenth Annual Biopharmaceutical Applied Statistics Symposium.

Full Issue: Vol. 63, Issue 4

Sci-Tech News

No abstract provided.

Environmental Risks Monitoring Of Shipwrecks In Italian Seas, Giuseppe Masetti, Fulvia Orsini

Center for Coastal and Ocean Mapping

After a description of the international regulatory framework, this paper examines the European project DE.E.P.P. and provides an overview of shipwreck databases in Italy. Afterwards, it reconstructs the recent history of the supertanker VLCC Haven which represents one of the largest Mediterranean shipwrecks. The findings of this paper emphasize the need to unify all the various agencies databases into a national Territorial Information System of potentially polluting wrecks. This System would be completed by all the information available in archives and press, to allow an adequate environmental risk monitoring and classification of shipwrecks in the Italian seas.

Estimation Of Sounding Uncertainty From Measurements Of Water Mass Variability, Jonathan Beaudoin, Brian R. Calder, J Hiebert, Gretchen Imahori

Center for Coastal and Ocean Mapping

Analysis techniques are introduced that allow for estimation of potential sounding uncertainty due to water mass variability from reconnaissance campaigns in which oceanographic parameters are measured at a high temporal and spatial resolution. The analysis techniques do not require sounding data, thus analyses can be tailored to match any survey system; this allows for pre-analysis campaigns to optimize survey instrumentation and sound speed profiling rates such that a desired survey specification can be maintained. Additionally, the output of the analysis methods can potentially provide a higher fidelity estimation of sounding uncertainty due to water mass variability than uncertainty models in …

Assessing The Merits Of The Ctbt, David W. Hafemeister

Physics

The Treaty on the Non-Proliferation of Nuclear Weapons and the nonproliferation regime have been weakened; perhaps no other issue demonstrates this as dramatically as the status of the Comprehensive Nuclear-Test-Ban Treaty (CTBT), the ratification of which the U.S. Senate rejected in October 1999. Despite the U.S. rejection, the test ban has strong international support—the most recent vote to promote the CTBT in the UN General Assembly passed overwhelmingly, with 175 votes to 1 (the United States) and three abstentions. The Obama administration favors U.S. ratification of the CTBT, but this is no guarantee that Washington will ratify the test ban. …

Characterization Of Arsenic-Tolerant Bacterial Cultures From The Lower Laguna Madre Of South Texas, Gemma A. Berlanga, Michael W. Persans, Thomas Eubanks, Kristine L. Lowe

Biology Faculty Publications and Presentations

Two forms of arsenic are found in the environment: As(V) and As(III), the latter being more toxic, water-soluble, and mobile. Microorganisms may increase the mobility of arsenic by reducing As(V) to As(III); however, detoxification and immobilization can occur via the oxidation of As(III) to As(V). The US EPA has set a minimum contaminant level of 10 parts per billion (ppb) for arsenic in drinking water. The research objective was to confirm the presence of arsenic-tolerant bacteria in the Lower Laguna Madre of south Texas. Sediment samples were collected and inoculated into growth media which contained either 2 mM As(III) or …

Activity-Aware Ecg-Based Patient Authentication For Remote Health Monitoring, Janani Sriram, Minho Shin, Tanzeem Choudhury, David Kotz

Dartmouth Scholarship

Mobile medical sensors promise to provide an efficient, accurate, and economic way to monitor patients' health outside the hospital. Patient authentication is a necessary security requirement in remote health monitoring scenarios. The monitoring system needs to make sure that the data is coming from the right person before any medical or financial decisions are made based on the data. Credential-based authentication methods (e.g., passwords, certificates) are not well-suited for remote healthcare as patients could hand over credentials to someone else. Furthermore, one-time authentication using credentials or trait-based biometrics (e.g., face, fingerprints, iris) do not cover the entire monitoring period and …

The Effects Of Intralayer Metal Composition Of Layered Double Hydroxides On Glass Transition, Dispersion, Thermal And Fire Properties Of Their Pmma Nanocomposites, Charles Manzi-Nshuti, Dan Chen, Shengpei Su, Charles A. Wilkie

Chemistry Faculty Research and Publications

A series of aluminum-containing layered double hydroxides (LDHs), containing Mg, Ca, Co, Ni, Cu and Zn as the divalent metals, have been prepared by the co-precipitation method and used to prepare nanocomposites of PMMA by in situ bulk polymerization. The additives were characterized by Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy (XRD) and thermogravimetric analysis while the polymer composites were characterized by XRD, transmission electron microscopy, differential scanning calorimetry and cone calorimetry. Polymerization of methyl methacrylate in the presence of these undecenoate LDHs results in composites with enhanced thermal stability. The glass transition temperatures of the composites and the pristine …

Online Fault Detection Of Induction Motors Using Independent Component Analysis And Fuzzy Neural Network, Zhaoxia Wang, C. S. Chang, X. German, W.W. Tan

Research Collection School Of Computing and Information Systems

This paper proposes the use of independent component analysis and fuzzy neural network for online fault detection of induction motors. The most dominating components of the stator currents measured from laboratory motors are directly identified by an improved method of independent component analysis, which are then used to obtain signatures of the stator current with different faults. The signatures are used to train a fuzzy neural network for detecting induction-motor problems such as broken rotor bars and bearing fault. Using signals collected from laboratory motors, the robustness of the proposed method for online fault detection is demonstrated for various motor …

Vireo/Dvmm At Trecvid 2009: High-Level Feature Extraction, Automatic Video Search, And Content-Based Copy Detection, Chong-Wah Ngo, Yu-Gang Jiang, Xiao-Yong Wei, Wanlei Zhao, Yang Liu, Jun Wang, Shiai Zhu, Shih-Fu Chang

Research Collection School Of Computing and Information Systems

This paper presents overview and comparative analysis of our systems designed for 3 TRECVID 2009 tasks: high-level feature extraction, automatic search, and content-based copy detection.

Computational Thinking...And Doing, George K. Thiruvathukal

Computer Science: Faculty Publications and Other Works

Computing in Science and Engineering, From the Editors

Mcc: A Runtime Verification Tool For Mcapi User Applications, Eric G. Mercer, Ganesh Gopalakrishnan, Jim Holt, Subodh Sharma

Faculty Publications

We present a dynamic verification tool MCC for Multicore Communication API applications – a new API for communication among cores. MCC systematically explores all relevant interleavings of an MCAPI application using a tailormade dynamic partial order reduction algorithm (DPOR). Our contributions are (i) a way to model the non-overtaking message matching relation underlying MCAPI calls with a high level algorithm to effect DPOR for MCAPI that controls the lower level details so that the intended executions happen at runtime; and (ii) a list of default safety properties that can be utilized in the process of verification. To our knowledge, this …

Banach Spaces On Infinitely Branching Trees, Annette B. Locke

Electronic Theses and Dissertations

An example of a Banach space, X_∞, with a nonseparable dual such that l₁ does not imbed in X_∞ is investigated. Not every weakly null sequence has a subsequence equivalent to the usual basis of c₀, but c₀ imbeds in many subspaces of X_∞. The space l₁ does imbed in X_∞^∗, the dual space of X_∞, yet weakly converging sequences in X_∞^∗ need not converge in norm.

New Learning Approach, Aurelia Spaulding

ALIVE Center Publications

No abstract provided.

Finite Temperature Effects In Magnetic Materials: Model And Ab Initio Studies, Aleksander L. Wysocki

Department of Physics and Astronomy: Dissertations, Theses, and Student Research

The understanding of finite temperature behavior of magnetic materials is of vital importance for spintronic applications. In this dissertation different theoretical techniques for studying magnetic thermodynamics of various materials are discussed. Cr₂O₃ is an antiferromagnetic insulator that was proposed to be a key component of new spintronic devices. The magnetic properties of Cr₂O₃ were studied using the LDA+U method. Magnetism was found to be very well described by the Heisenberg model. Subsequently, magnetic thermodynamics was explored using quantum pair cluster approximation. Overall, very good agreement with experiment was found for the ground state and …

Simulations Of The Dipole-Dipole Interaction Between Two Spatially Separated Groups Of Rydberg Atoms, Thomas J. Carroll, Christopher Daniel, Leah Hoover, Timothy Sidie, Michael Noel

Physics Faculty Research and Scholarship

The dipole-dipole interaction among ultracold Rydberg atoms is simulated. We examine a general interaction scheme in which two atoms excited to the x and x(') states are converted to y and y(') states via a Förster resonance. The atoms are arranged in two spatially separated groups, each consisting of only one species of atom. We monitor the state mixing by recording the fraction of atoms excited to the y(') state as the distance between the two groups is varied. With zero detuning a many-body effect that relies on always resonant interactions causes the state mixing to have a finite range. …

Fisheries Research Report No.196 - Management Of Bioeroding Sponges In Wild Stocks Of Pinctada Maxima In Western Australia, Sabine Daume, Jane Fromont, Anthony M. Hart

Fisheries research reports

Final FRDC Report – Project 2005/074

The Western Australian fishery is the only remaining significant fishery for pearl oysters in the world and comprises most of the exported pearl product of Australia, currently worth around $125 million annually. The majority of pearl shells used to culture pearls come from the pearling beds in the inshore waters near Broome. The fishery for pearl oysters preferentially targets smaller ‘culture’ shell (4-5 years age class, 120mm - 160mm shell length) that are more suitable for growing pearls, leaving larger MOP oysters (6+ age class, 175mm+) on the fishing grounds.

Silver-lipped pearl oysters (Pinctada …

Stability Of The Rotation Axis In High‐Resolution Mantle Circulation Models: Weak Polar Wander Despite Strong Core Heating, K. Schaber, H. -P. Bunge, B. S. A. Schuberth, Rocco Malservisi, A. Horbach

School of Geosciences Faculty and Staff Publications

Growing evidence points to a substantial heat flow across the core‐mantle boundary (CMB), but the rotational stability of strongly bottom heated mantle flow with prominent upwelling plumes is poorly known. Here we calculate polar motion for the past 100 Myr induced in a new class of isochemical high‐resolution mantle circulation models (MCMs) with Earth‐like convective vigor and up to 12 TW core heat flux. Our MCMs include internal heating and a simple three‐layer viscosity profile associated with the lithosphere (1023 Pa s) and the upper (1021 Pa s) and the lower mantle (1023 Pa s), separated at 100 and 650 …

Polymer Nanocomposites Using Zinc Aluminum And Magnesium Aluminum Oleate Layered Double Hydroxides: Effects Of The Polymeric Compatibilizer And Of Composition On The Thermal And Fire Properties Of Pp/Ldh Nanocomposites, Charles Manzi-Nshuti, Ponusa Songtipya, Evangelos Manias, Maria Del Mar Jimenez-Gasco, Jeanne Hossenlopp, Charles A. Wilkie

Chemistry Faculty Research and Publications

A series of five oleate-containing layered double hydroxides with varied ratios of zinc to magnesium, i.e., with the general formula Zn_2−yMg_yAl(OH)₆ [CH₃(CH₂)₇CHCH(CH₂)₇COO]·nH₂O, were synthesized and used to prepare nanocomposites of polypropylene (PP). The nanomaterials were characterized by elemental analysis, attenuated total reflection-infrared spectroscopy (ATR-IR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA), while the composites were characterized by XRD, TGA, transmission electron microscopy (TEM) and cone calorimetry. The zinc-containing LDH showed better dispersion in the polymer at the micrometer level …

Fragmentation Properties Of Three-Membered Ring Heterocyclic Molecules By Partial Ion Yield Spectroscopy: C2h4o And C2h4s, Wayne C. Stolte, I. Dumitriu, S-W Yu, Gunnar Ohrwall, Maria Novella Piancastelli, Dennis W. Lindle

Chemistry and Biochemistry Faculty Research

We investigated the photofragmentation properties of two three-membered ring heterocyclic molecules, C₂H₄O and C₂H₄S, by total and partial ion yield spectroscopy. Positive and negative ions have been collected as a function of photon energy around the C 1s and O 1s ionization thresholds in C₂H₄O, and around the S 2p and C 1s thresholds in C₂H₄S. We underline similarities and differences between these two analogous systems. We present a new assignment of the spectral features around the C K-edge and the sulfur L_{2 …}

Climate, Agricultural Strategies, And Sustainability In The Precolumbian Andes, Charles Ortloff, Michael E. Moseley

Andean Past

No abstract provided.

Microbial-Induced Heterogeneity In The Acoustic Properties Of Porous Media, Caroline A. Davis, Laura J. Pyrak-Nolte, Estella A. Atekwana, D. Dale, Werkema, Marisa E. Haugen

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

It is not known how biofilms affect seismic wave propagation in porous media. Such knowledge is critical for assessing the utility of seismic techniques for imaging biofilm development and their effects in field settings. Acoustic wave data were acquired over a two-dimensional region of a microbial-stimulated sand column and an unstimulated sand column. The acoustic signals from the unstimulated column were relatively uniform over the 2D scan region. The data from the microbial-stimulated column exhibited a high degree of spatial heterogeneity in the acoustic wave amplitude, with some regions exhibiting significant increases in attenuation while others exhibited decreases. Environmental scanning …

Mining Communities In Networks: A Solution For Consistency And Its Evaluation, Haewoon Kwak, Yoonchan Choi, Young-Ho Eom, Hawoong Jeong, Sue Moon

Research Collection School Of Computing and Information Systems

Online social networks pose significant challenges to computer scientists, physicists, and sociologists alike, for their massive size, fast evolution, and uncharted potential for social computing. One particular problem that has interested us is community identification. Many algorithms based on various metrics have been proposed for communities in networks [18, 24], but a few algorithms scale to very large networks. Three recent community identification algorithms, namely CNM [16], Wakita [59], and Louvain [10], stand out for their scalability to a few millions of nodes. All of them use modularity as the metric of optimization. However, all three algorithms produce inconsistent communities …

Static Validation Of C Preprocessor Macros, Andreas Saebjornsen, Lingxiao Jiang, Daniel Quinlan, Zhendong Su

Research Collection School Of Computing and Information Systems

The widely used C preprocessor (CPP) is generally considered a source of difficulty for understanding and maintaining C/C++ programs. The main reason for this difficulty is CPP’s purely lexical semantics, i.e., its treatment of both input and output as token streams. This can easily lead to errors that are difficult to diagnose, and it has been estimated that up to 20% of all macros are erroneous. To reduce such errors, more restrictive, replacement languages for CPP have been proposed to limit expanded macros to be valid C syntactic units. However, there is no practical tool that can effectively validate CPP …

Udel/Smu At Trec 2009 Entity Track, Wei Zheng, Swapna Gottipati, Jing Jiang, Hui Fang

Research Collection School Of Computing and Information Systems

We report our methods and experiment results from the collaborative participation of the InfoLab group from University of Delaware and the school of Information Systems from Singapore Management University in the TREC 2009 Entity track. Our general goal is to study how we may apply language modeling approaches and natural language processing techniques to the task. Specically, we proposed to find supporting information based on segment retrieval, to extract entities using Stanford NER tagger, and to rank entities based on a previously proposed probabilistic framework for expert finding.

Dataset Threshold For The Performance Estimators In Supervised Machine Learning Experiments, Zanifa Omary, Fredrick Mtenzi

Conference papers

The establishment of dataset threshold is one among the first steps when comparing the performance of machine learning algorithms. It involves the use of different datasets with different sample sizes in relation to the number of attributes and the number of instances available in the dataset. Currently, there is no limit which has been set for those who are unfamiliar with machine learning experiments on the categorisation of these datasets, as either small or large, based on the two factors. In this paper we perform experiments in order to establish dataset threshold. The established dataset threshold will help unfamiliar supervised …

City Of Newport News, Virginia Shoreline Inventory Report Methods And Guidelines, Marcia Berman, Harry Berquist, Sharon Killeen, Carl Hershner, Karinna Nunez, Karen Reay, Tamia Rudnicky, Daniel Schatt, Dave Weiss

Reports

This shoreline inventory is developed as a tool for assessing conditions along the tidal shoreline in the City of Newport News. Field data were collected during July and September 2002, and data were updated using VBMP 2006/2007 imagery. Conditions are reported for three zones within the immediate riparian river area: riparian land use, bank and buffers, and the shoreline. A series of maps and tabular data are published to illustrate and quantify results of an extensive shoreline survey. Shorelines of the James River, Skiffes Creek, Warwick River and Deep Creek, including small tributaries, were surveyed. Some sections were coded using …

User Interfaces For Visual Analysis And Monitoring In Business Intelligence, Lars Grammel, Margaret-Anne Storey, Christoph Treude

Research Collection School Of Computing and Information Systems

Business intelligence is concerned with understanding and leveraging the vast amounts of information stored in the databases of modern enterprises. Visualization techniques have been used to make sense of this data for a long time, first in the form of simple charts, and nowadays in the form of interactive visualizations. By leveraging the strengths of the human perceptual system and incorporating user interaction, they support the flexible analysis of data as well as data monitoring by users. The recent progress in the fields of information and data visualization as well as new hardware developments and trends in business intelligence have …