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2009

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Articles 2581 - 2610 of 7616

Full-Text Articles in Physical Sciences and Mathematics

Impact Of The Intraseasonal Variability Of Large-Scale Circulation Over The Western North Pacific On The Characteristics Of Tropical Cyclone Track, T. C. Chen, Shih-Yu (Simon) Wang, M. C. Yen, A. J. Clark Jun 2009

Impact Of The Intraseasonal Variability Of Large-Scale Circulation Over The Western North Pacific On The Characteristics Of Tropical Cyclone Track, T. C. Chen, Shih-Yu (Simon) Wang, M. C. Yen, A. J. Clark

Plants, Soils, and Climate Faculty Publications

The life cycle of the Southeast Asian–western North Pacific monsoon circulation is established by the northward migrations of the monsoon trough and the western Pacific subtropical anticyclone, and is reflected by the intraseasonal variations of mo nsoon westerlies and trad e easterlies in the form of an east–west seesaw oscillation. In this paper, an effort is made to disclose the influence of this monsoon circulation on tropical cyclone tracks during its different ph ases using composite charts of large-scale circulation for certain types of tracks. A majority of straight-moving (recurving) tropical cyclones appear during weak (strong) monsoon west- erlies and …


Gaussian Perturbations Of Circle Maps: A Spectral Approach, John Mayberry Jun 2009

Gaussian Perturbations Of Circle Maps: A Spectral Approach, John Mayberry

College of the Pacific Faculty Articles

In this work, we examine spectral properties of Markov transition operators corresponding to Gaussian perturbations of discrete time dynamical systems on the circle. We develop a method for calculating asymptotic expressions for eigenvalues (in the zero noise limit) and show that changes to the number or period of stable orbits for the deterministic system correspond to changes in the number of limiting modulus 1 eigenvalues of the transition operator for the perturbed process. We call this phenomenon a λ-bifurcation. Asymptotic expressions for the corresponding eigenfunctions and eigenmeasures are also derived and are related to Hermite functions. © Institute of Mathematical …


Analysis Of Rotating Flow Around A Growing Protein Crystal, Daniel N. Riahi, Charles W. Obare Jun 2009

Analysis Of Rotating Flow Around A Growing Protein Crystal, Daniel N. Riahi, Charles W. Obare

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

We consider the problem of steady flow around a growing protein crystal in a medium of its solution in a normal gravity environment. The whole flow system is assumed to be rotating with a constant angular velocity about a vertical axis which is anti-parallel to the gravity vector. Convective flow takes place due to the solute depletion around the growing crystal which leads to a buoyancy driven flow. Such convective flow can produce inhomogeneous solute concentration, which subsequently generate non-uniformities in the crystal’s structure finalizing lower quality protein crystal. Using scaling analysis within a diffusion boundary layer around the crystal, …


Deamon: Energy-Efficient Sensor Monitoring, Minho Shin, Patrick Tsang, David Kotz, Cory Cornelius Jun 2009

Deamon: Energy-Efficient Sensor Monitoring, Minho Shin, Patrick Tsang, David Kotz, Cory Cornelius

Dartmouth Scholarship

In people-centric opportunistic sensing, people offer their mobile nodes (such as smart phones) as platforms for collecting sensor data. A sensing application distributes sensing `tasks,' which specify what sensor data to collect and under what conditions to report the data back to the application. To perform a task, mobile nodes may use on-board sensors, a body-area network of personal sensors, or sensors from neighboring nodes that volunteer to contribute their sensing resources. In all three cases, continuous sensor monitoring can drain a node's battery. \par We propose DEAMON (Distributed Energy-Aware MONitoring), an energy-efficient distributed algorithm for long-term sensor monitoring. Our …


The Onset Of Warps In Spitzer Observations Of Edge-On Spiral Galaxies., Kanak Saha, Roelof De Jong, Benne W. Holwerda Jun 2009

The Onset Of Warps In Spitzer Observations Of Edge-On Spiral Galaxies., Kanak Saha, Roelof De Jong, Benne W. Holwerda

Faculty and Staff Scholarship

We analyse warps in the nearby edge-on spiral galaxies observed in the Spitzer/Infrared Array Camera (IRAC )4.5-μm band. In our sample of 24 galaxies, we find evidence of warp in 14 galaxies. We estimate the observed onset radii for the warps in a subsample of 10 galaxies. The dark matter distribution in each of these galaxies are calculated using the mass distribution derived from the observed light distribution and the observed rotation curves. The theoretical predictions of the onset radii for the warps are then derived by applying a self-consistent linear response theory to the obtained mass models for six …


Applying Domain Knowledge From Structured Citation Formats To Text And Data Mining: Examples Using The Cite Architecture, D Neel Smith, Gabriel A. Weaver Jun 2009

Applying Domain Knowledge From Structured Citation Formats To Text And Data Mining: Examples Using The Cite Architecture, D Neel Smith, Gabriel A. Weaver

Computer Science Technical Reports

Domain knowledge expressed in structured citation formats can be exploited in data mining. We propose four structural properties of canonically cited texts, then look at to two classic problems in the study of the scholia, or ancient scholarly commentary, found in the manuscripts of the Iliad. We cluster citations of scholia to analyze their distribution in different manuscripts; this leads to a revised view of how the manuscripts' scribes drew on their source material. Correlated frequencies of named entities suggest that one group of manuscripts had access to material more closely based on the work of the greatest Hellenistic editor …


A Computational Framework For Certificate Policy Operations, Gabriel A. Weaver, Scott Rea, Sean W. Smith Jun 2009

A Computational Framework For Certificate Policy Operations, Gabriel A. Weaver, Scott Rea, Sean W. Smith

Computer Science Technical Reports

The trustworthiness of any Public Key Infrastructure (PKI) rests upon the expectations for trust, and the degree to which those ex- pectations are met. Policies, whether implicit as in PGP and SDSI/SPKI or explicitly required as in X.509, document expectations for trust in a PKI. The widespread use of X.509 in the context of global e-Science infrastructures, financial institutions, and the U.S. Federal government demands efficient, transparent, and reproducible policy decisions. Since current manual processes fall short of these goals, we designed, built, and tested computational tools to process the citation schemes of X.509 certificate policies defined in RFC 2527 …


Phenylbenzimidazole-Based New Bipolar Host Materials For Efficient Phosphorescent Organic Light-Emitting Diodes, Shin-Ya Takizawa, Victor A. Montes, Pavel Anzenbacher Jr. Jun 2009

Phenylbenzimidazole-Based New Bipolar Host Materials For Efficient Phosphorescent Organic Light-Emitting Diodes, Shin-Ya Takizawa, Victor A. Montes, Pavel Anzenbacher Jr.

Chemistry Faculty Publications

Two new bipolar host materials based on a 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene (TPBI) core with the carbazole and diphenylamine groups were designed, synthesized, and applied in phosphorescent organic light-emitting diodes (PhOLEDs). The DFT calculations indicated desirable distribution of HOMO and LUMO densities, suggesting potential for bipolar charge transport. In addition, the electrochemical and phosphorescence studies revealed that neither the LUMO level nor the triplet energies differ significantly from the parent TPBI suggesting that the new materials would be suitable as hosts capable of both electron and hole transport and suitable for harvesting green electrophosphorescence. As a result of broader charge recombination zone resulting …


Electronic Properties Of 4-Substituted Naphthalimides, Pavel Kucheryavy, Guifeng Li, Shubham Vyas, Christopher Hadad, Ksenija D. Glusac Jun 2009

Electronic Properties Of 4-Substituted Naphthalimides, Pavel Kucheryavy, Guifeng Li, Shubham Vyas, Christopher Hadad, Ksenija D. Glusac

Chemistry Faculty Publications

This paper describes a study of excited-state properties of naphthalmide (NI) and four 4-substituted derivatives: 4-chloronaphthalimide (Cl-NI), 4-methylthionaphthalmide (MeS-NI), 4-nitronaphthalimide (O(2)N-NI), and 4-(N,N-dimethylaminonaphthalimide (Me(2)N-NI). Steady-state absorption and fluorescence spectra were collected in solvents of varying polarity to determine the excited-state character of NI derivatives. Furthermore. the excited-state dynamics were studied Using femtosecond transient absorption spectroscopy. The experimental findings were compared to calculated data obtained using time-dependent density functional (TD-DFT) methods. We found that light absorption by all NI derivatives leads to the production of the second excited state (S(2)), which was found to have a n,pi* character. Within similar to …


Energetic Path Finding Across Massive Terrain Data, Andrew N. Tsui Jun 2009

Energetic Path Finding Across Massive Terrain Data, Andrew N. Tsui

Master's Theses

Before there were airplanes, cars, trains, boats, or bicycles, the primary means of transportation was on foot. Unfortunately, many of the trails used by ancient travelers have long since been abandoned. We present a software tool which can help visualize and predict where these forgotten trails might lie through the use of a human-centered cost metric. By comparing the paths generated by our software with known historical trails, we demonstrate how the tool can indicate likely trails used by ancient travelers. In addition, this new tool provides novel visualizations to better help the user understand alternate paths, effect of terrain, …


Super-Resolution Via Recapture And Bayesian Effect Modeling, Bryan S. Morse, Kevin Seppi, Neil Toronto, Dan A. Ventura Jun 2009

Super-Resolution Via Recapture And Bayesian Effect Modeling, Bryan S. Morse, Kevin Seppi, Neil Toronto, Dan A. Ventura

Faculty Publications

This paper presents Bayesian edge inference (BEI), a single-frame super-resolution method explicitly grounded in Bayesian inference that addresses issues common to existing methods. Though the best give excellent results at modest magnification factors, they suffer from gradient stepping and boundary coherence problems by factors of 4x. Central to BEI is a causal framework that allows image capture and recapture to be modeled differently, a principled way of undoing downsampling blur, and a technique for incorporating Markov random field potentials arbitrarily into Bayesian networks. Besides addressing gradient and boundary issues, BEI is shown to be competitive with existing methods on published …


Tidal Sediment Yield Estimate Methodology In Virginia For The Chesapeake Bay Program Water Quality Model, C. Scott Hardaway Jr., Donna A. Milligan, Lyle M. Varnell, Julie Herman Jun 2009

Tidal Sediment Yield Estimate Methodology In Virginia For The Chesapeake Bay Program Water Quality Model, C. Scott Hardaway Jr., Donna A. Milligan, Lyle M. Varnell, Julie Herman

Reports

Water quality in Chesapeake Bay has degraded over the past 50 years with respect to oxygen depletion and reduced light attenuation. While the causes are numerous, sediment resuspension from wave and tidal action cloud the water column and reduce light attenuation thereby negatively affecting submerged aquatic vegetation (SAV) beds. Sediments on the Bay bottom come from upland runoff and shoreline erosion, each of which has significant contributions to the loading of sediments into estuary. The purpose of this report is to assess the present methods used to calculate sediment loading from tidal shoreline erosion that is input to the Chesapeake …


Understanding Terrorism Through The Use Of Gis - Crj 346: Terrorism And Society, Joseph F. Ryan, Ph.D., Daniel Farkas, Ph.D. Jun 2009

Understanding Terrorism Through The Use Of Gis - Crj 346: Terrorism And Society, Joseph F. Ryan, Ph.D., Daniel Farkas, Ph.D.

Cornerstone 3 Reports : Interdisciplinary Informatics

This is a study that concentrates on methodologies on collecting and analysis of intelligence information.


Meta Analyses Of Multiple Baseline Time Series Design Intervention Models For Dependent And Independent Series, Oluwagbohunmi Adetunji Awosoga Jun 2009

Meta Analyses Of Multiple Baseline Time Series Design Intervention Models For Dependent And Independent Series, Oluwagbohunmi Adetunji Awosoga

Dissertations

Most wireless networks are deployed strictly in the radio frequency (RF) domain, since RF channels provide natural support for radial broadcast operations. However, the downside of RF channels is that they introduce many limiting externalities that make providing scalable quality of service (QoS) support difficult, if not intractable. These well-known technical challenges include bandwidth scarcity, lack of security, high interference, and high bit error rates.

Faced with such daunting obstacles to QoS, the use of Free Space Optics (FSO) for wireless communications has been proposed in which it has the potential to support higher link data rates compared to present …


Applying Sanitizable Signature To Web-Service-Enabled Business Processes: Going Beyond Integrity Protection, Kar Way Tan, Robert H. Deng Jun 2009

Applying Sanitizable Signature To Web-Service-Enabled Business Processes: Going Beyond Integrity Protection, Kar Way Tan, Robert H. Deng

Research Collection School Of Computing and Information Systems

This paper studies the scenario where data in business documents is aggregated by different entities via the use of web services in streamlined business processes. The documents are transported within the Simple Object Access Protocol (SOAP) messages and travel through multiple intermediary entities, each potentially makes changes to the data in the documents. The WS-Security provides integrity protection by allowing portions of a SOAP message to be signed using eXtensible Markup Language (XML) signature scheme. This method however, has not considered the situation where a portion of data may be modified by another entity, therefore a need to allow the …


Architectural Dualities In Complex Systems: Components, Interfaces, Technologies And Organizations, C. Jason Woodard, Joel West Jun 2009

Architectural Dualities In Complex Systems: Components, Interfaces, Technologies And Organizations, C. Jason Woodard, Joel West

Research Collection School Of Computing and Information Systems

Research on technological innovation and product development has long recognized the importance of product architecture, and many scholars have explored its relationship to the organizational structure of the product development process. Product architecture, in turn, has long encompassed both the allocation of functionality to components and the pattern of linkages between them. In this paper, we forge new connections among these established ideas by examining them as two pairs of dual relationships. First, we draw attention to the duality between components and interfaces. While innovation and product development researchers have historically emphasized the partitioning of products and systems into components, …


A Revisit Of Generative Model For Automatic Image Annotation Using Markov Random Fields, Yu Xiang, Xiangdong Zhou, Tat-Seng Chua, Chong-Wah Ngo Jun 2009

A Revisit Of Generative Model For Automatic Image Annotation Using Markov Random Fields, Yu Xiang, Xiangdong Zhou, Tat-Seng Chua, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

Much research effort on Automatic Image Annotation (AIA) has been focused on Generative Model, due to its well formed theory and competitive performance as compared with many well designed and sophisticated methods. However, when considering semantic context for annotation, the model suffers from the weak learning ability. This is mainly due to the lack of parameter setting and appropriate learning strategy for characterizing the semantic context in the traditional generative model. In this paper, we present a new approach based on Multiple Markov Random Fields (MRF) for semantic context modeling and learning. Differing from previous MRF related AIA approach, we …


Cyber Attacks: Cross-Country Interdependence And Enforcement, Qiu-Hong Wang, Seung Hyun Kim Jun 2009

Cyber Attacks: Cross-Country Interdependence And Enforcement, Qiu-Hong Wang, Seung Hyun Kim

Research Collection School Of Computing and Information Systems

This study empirically characterizes the interdependence in cyber attacks and examines theimpact from the first international treaty against cybercrimes (Convention on Cybercrimes:Europe Treaty Series No. 185). With the data covering 62 countries over the period from year2003 to 2007, we find that, international cooperation in enforcement as measured by theindicator of joining the Convention on Cybercrimes, deterred cyber attacks originating from anyparticular country by 15.81% ~ 24.77% (in 95% confidence interval). Second, joining theConvention also affected the interdependence in cyber attacks from two angels. First, for anypair of country, closer status in joining or not joining the Convention was associated …


Intentional Learning Agent Architecture, Budhitama Subagdja, Liz Sonenberg, Iyad Rahwan Jun 2009

Intentional Learning Agent Architecture, Budhitama Subagdja, Liz Sonenberg, Iyad Rahwan

Research Collection School Of Computing and Information Systems

Dealing with changing situations is a major issue in building agent systems. When the time is limited, knowledge is unreliable, and resources are scarce, the issue becomes more challenging. The BDI (Belief-Desire-Intention) agent architecture provides a model for building agents that addresses that issue. The model can be used to build intentional agents that are able to reason based on explicit mental attitudes, while behaving reactively in changing circumstances. However, despite the reactive and deliberative features, a classical BDI agent is not capable of learning. Plans as recipes that guide the activities of the agent are assumed to be static. …


What Is Ccs?, University Of North Dakota. Energy And Environmental Research Center Jun 2009

What Is Ccs?, University Of North Dakota. Energy And Environmental Research Center

EERC Brochures and Fact Sheets

Fact sheet about carbon capture and storage (CCS) and the Plains CO2 Reduction (PCOR) Partnership. Outlines the three phases of U.S. Department of Energy National Energy Technology Laboratory’s Regional Carbon Sequestration Partnership program.


Confidence Intervals For The Ratio Of Two Exponential Means With Applications To Quality Control, James Albert Polcer,Iii Jun 2009

Confidence Intervals For The Ratio Of Two Exponential Means With Applications To Quality Control, James Albert Polcer,Iii

Student Research Conference Select Presentations

We considered the problem of statistical quality control based on the ratio of two population means. We restrict the discussion for two exponential rates, which are commonly used for modeling failure times of components, machines, or systems. Closed form expressions via the moment generation function (MGF) technique will be presented, and numerical examples will be shown using engineering data sets.


Store And Forward Routing For Sparse Pico-Satellite Sensor Networks With Data-Mules, Trevor Joseph Koritza Jun 2009

Store And Forward Routing For Sparse Pico-Satellite Sensor Networks With Data-Mules, Trevor Joseph Koritza

Master's Theses

Satellites are playing an increasingly important role in collecting scientific information, providing communication services, and revolutionizing navigation. Until recently satellites were large and very expensive, creating a high barrier to entry that only large corporations and government agencies could overcome. In the past few years the CubeSat project at California Polytechnic University in San Luis Obispo (Cal Poly) has worked to refine the design and launching of small, lightweight, and less expensive satellites called pico-satellites, opening space up to a wider audience. Now that Cal Poly has the launch logistics and hardware under control, a new problem has arisen. These …


Boundless Fluids Using The Lattice-Boltzmann Method, Kyle J. Haughey Jun 2009

Boundless Fluids Using The Lattice-Boltzmann Method, Kyle J. Haughey

Master's Theses

Computer-generated imagery is ubiquitous in today's society, appearing in advertisements, video games, and computer-animated movies among other places. Much of this imagery needs to be as realistic as possible, and animators have turned to techniques such as fluid simulation to create scenes involving substances like smoke, fire, and water. The Lattice-Boltzmann Method (LBM) is one fluid simulation technique that has gained recent popularity due to its relatively simple basic algorithm and the ease with which it can be distributed across multiple processors. Unfortunately, current LBM simulations also suffer from high memory usage and restrict free surface fluids to domains of …


Sequence Characterization Of Riordan Arrays, Tian-Xiao He, Renzo Sprugnoli May 2009

Sequence Characterization Of Riordan Arrays, Tian-Xiao He, Renzo Sprugnoli

Tian-Xiao He

In the realm of the Riordan group, we consider the characterization of Riordan arrays by means of the A- and Z-sequences. It corresponds to a horizontal construction of a Riordan array, whereas the traditional approach is through column generating functions. We show how the A- and Z-sequences of the product of two Riordan arrays are derived from those of the two factors; similar results are obtained for the inverse. We also show how the sequence characterization is applied to construct easily a Riordan array. Finally, we give the characterizations relative to some subgroups of the Riordan group, in particular, of …


Overcoming Visibility Issues In A Small-To-Medium Retailer Using Automatic Identification And Data Capture Technology: An Evolutionary Approach, Dane Hamilton, K. Michael, Samuel F. Wamba May 2009

Overcoming Visibility Issues In A Small-To-Medium Retailer Using Automatic Identification And Data Capture Technology: An Evolutionary Approach, Dane Hamilton, K. Michael, Samuel F. Wamba

Professor Katina Michael

The aim of this paper is to review the inventory control practices of a small-to-medium retailer, in order to identify common challenges these organizations experience with respect to automated data capture (ADC) and the implementation of an enterprise wide information system. The study explores a single case of a hardware store in a regional town of NSW, Australia. Four semi-structured interviews were conducted with employees of a small-to-medium retailer focusing on issues related to inventory control including: delivery discrepancies, the checking and sorting of orders, locating stock and goods, loss prevention, customer purchasing and point of sale processing and replenishment. …


Intra-Annual Comparison Of Mesospheric Gravity Waves Over Halley And Rothera Stations, Antarctica., Jonathan R. Pugmire, Mike J. Taylor, Kim Nielsen May 2009

Intra-Annual Comparison Of Mesospheric Gravity Waves Over Halley And Rothera Stations, Antarctica., Jonathan R. Pugmire, Mike J. Taylor, Kim Nielsen

Jonathan Pugmire

As part of a collaborative program between British Antarctic Survey and Utah State University, we present an intra-annual study of short-period, mesospheric gravity wave events observed over Antarctica in the near infrared OH emission. The measurements were made using an all-sky airglow imager operated at either Halley Station on the Brunt Ice Shelf, or Rothera Station, situated on the Antarctic Peninsula. A total of six austral winter seasons have been analyzed (2000-2006). This study comprises the first detailed winter seasonal investigation of short-period mesospheric gravity waves at high-Antarctic latitudes. Distributions of their observed wave parameters were found to be similar …


The Diagnostic Challenge Competition: Probabilistic Techniques For Fault Diagnosis In Electrical Power Systems, Brian W. Ricks, Ole J. Mengshoel May 2009

The Diagnostic Challenge Competition: Probabilistic Techniques For Fault Diagnosis In Electrical Power Systems, Brian W. Ricks, Ole J. Mengshoel

Ole J Mengshoel

Reliable systems health management is an important research area of NASA. A health management system that can accurately and quickly diagnose faults in various on-board systems of a vehicle will play a key role in the success of current and future NASA missions. We introduce in this paper the ProDiagnose algorithm, a diagnostic algorithm that uses a probabilistic approach, accomplished with Bayesian Network models compiled to Arithmetic Circuits, to diagnose these systems. We describe the ProDiagnose algorithm, how it works, and the probabilistic models involved. We show by experimentation on two Electrical Power Systems based on the ADAPT testbed, used …


Interview With Ted Labbe, Depave, 2009 (Audio), Ted Labbe May 2009

Interview With Ted Labbe, Depave, 2009 (Audio), Ted Labbe

All Sustainability History Project Oral Histories

Interview of Ted Labbe by Chris Fogg in Portland, Oregon on May 31st, 2009.

The interview index is available for download.


Self Similar Flows In Finite Or Infinite Two Dimensional Geometries, Leonardo Xavier Espin Estevez May 2009

Self Similar Flows In Finite Or Infinite Two Dimensional Geometries, Leonardo Xavier Espin Estevez

Dissertations

This study is concerned with several problems related to self-similar flows in pulsating channels. Exact or similarity solutions of the Navier-Stokes equations are of practical and theoretical importance in fluid mechanics. The assumption of self-similarity of the solutions is a very attractive one from both a theoretical and a practical point of view. It allows us to greatly simplify the Navier-Stokes equations into a single nonlinear one-dimensional partial differential equation (or ordinary differential equation in the case of steady flow) whose solutions are also exact solutions of the Navier-Stokes equations in the sense that no approximations are required in order …


Predictive Decoding Of Neural Data, Yaroslav O. Halchenko May 2009

Predictive Decoding Of Neural Data, Yaroslav O. Halchenko

Dissertations

In the last five decades the number of techniques available for non-invasive functional imaging has increased dramatically. Researchers today can choose from a variety of imaging modalities that include EEG, MEG, PET, SPECT, MRI, and fMRI.

This doctoral dissertation offers a methodology for the reliable analysis of neural data at different levels of investigation. By using statistical learning algorithms the proposed approach allows single-trial analysis of various neural data by decoding them into variables of interest. Unbiased testing of the decoder on new samples of the data provides a generalization assessment of decoding performance reliability. Through consecutive analysis of the …