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

Physical Sciences and Mathematics Commons™

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

2010

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 91 - 120 of 8620

Full-Text Articles in Physical Sciences and Mathematics

Shortest Path Computation On Air Indexes, Georgios Kellaris, Kyriakos Mouratidis Dec 2010

Shortest Path Computation On Air Indexes, Georgios Kellaris, Kyriakos Mouratidis

Kyriakos MOURATIDIS

Shortest path computation is one of the most common queries in location-based services that involve transportation net- works. Motivated by scalability challenges faced in the mo- bile network industry, we propose adopting the wireless broad- cast model for such location-dependent applications. In this model the data are continuously transmitted on the air, while clients listen to the broadcast and process their queries locally. Although spatial problems have been considered in this environment, there exists no study on shortest path queries in road networks. We develop the rst framework to compute shortest paths on the air, and demonstrate the practicality and …

Go to article

A Threshold-Based Algorithm For Continuous Monitoring Of K Nearest Neighbors, Kyriakos Mouratidis, Dimitris Papadias, Spiridon Bakiras, Yufei Tao Dec 2010

A Threshold-Based Algorithm For Continuous Monitoring Of K Nearest Neighbors, Kyriakos Mouratidis, Dimitris Papadias, Spiridon Bakiras, Yufei Tao

Kyriakos MOURATIDIS

Assume a set of moving objects and a central server that monitors their positions over time, while processing continuous nearest neighbor queries from geographically distributed clients. In order to always report up-to-date results, the server could constantly obtain the most recent position of all objects. However, this naïve solution requires the transmission of a large number of rapid data streams corresponding to location updates. Intuitively, current information is necessary only for objects that may influence some query result (i.e., they may be included in the nearest neighbor set of some client). Motivated by this observation, we present a threshold-based algorithm …

Go to article

Preference Queries In Large Multi-Cost Transportation Networks, Kyriakos Mouratidis, Yimin Lin, Man Lung Yiu Dec 2010

Preference Queries In Large Multi-Cost Transportation Networks, Kyriakos Mouratidis, Yimin Lin, Man Lung Yiu

Kyriakos MOURATIDIS

Research on spatial network databases has so far considered that there is a single cost value associated with each road segment of the network. In most real-world situations, however, there may exist multiple cost types involved in transportation decision making. For example, the different costs of a road segment could be its Euclidean length, the driving time, the walking time, possible toll fee, etc. The relative significance of these cost types may vary from user to user. In this paper we consider such multi-cost transportation networks (MCN), where each edge (road segment) is associated with multiple cost values. We formulate …

Go to article

Crystalline Order On Catenoidal Capillary Bridges, Mark Bowick, Zhenwei Yao Dec 2010

Crystalline Order On Catenoidal Capillary Bridges, Mark Bowick, Zhenwei Yao

Physics - All Scholarship

We study the defect structure of crystalline particle arrays on negative Gaussian curvature capillary bridges with vanishing mean curvature (catenoids). The threshold aspect ratio for the appearance of isolated disclinations is found and the optimal positions for dislocations determined. We also discuss the transition from isolated disclinations to scars as particle number and aspect ratio are varied.

Go to article

Crystalline Order On Catenoidal Capillary Bridges, Mark Bowick, Zhenwei Yao Dec 2010

Crystalline Order On Catenoidal Capillary Bridges, Mark Bowick, Zhenwei Yao

Physics - All Scholarship

We study the defect structure of crystalline particle arrays on negative Gaussian curvature capillary bridges with vanishing mean curvature (catenoids). The threshold aspect ratio for the appearance of isolated disclinations is found and the optimal positions for dislocations determined. We also discuss the transition from isolated disclinations to scars as particle number and aspect ratio are varied.

Go to article

The Kepler Light Curve Of V344 Lyrae: Constraining The Thermal-Viscous Limit Cycle Instability, John K. Cannizzo, Martin D. Still, Steve B. Howell, Matt A. Wood, Alan P. Smale Dec 2010

The Kepler Light Curve Of V344 Lyrae: Constraining The Thermal-Viscous Limit Cycle Instability, John K. Cannizzo, Martin D. Still, Steve B. Howell, Matt A. Wood, Alan P. Smale

Aerospace, Physics, and Space Science Faculty Publications

We present time-dependent modeling based on the accretion disk limit cycle model for a 270 d light curve of the short-period SU UMa-type dwarf nova V344 Lyr taken by Kepler. The unprecedented precision and cadence (1 minute) far surpass that generally available for long-term light curves. The data encompass two superoutbursts and 17 normal (i.e., short) outbursts. The main decay of the superoutbursts is nearly perfectly exponential, decaying at a rate ~12 d mag−1, while the much more rapid decays of the normal outbursts exhibit a faster-than-exponential shape. Our modeling using the basic accretion disk limit cycle can produce the …

Go to article

University Of Richmond Climate Action Plan, University Of Richmond Dec 2010

University Of Richmond Climate Action Plan, University Of Richmond

Plans

The Climate Action Plan for the University of Richmond establishes the framework for achieving the University’s climate action goals under the American College and University Presidents Climate Commitment. The University of Richmond’s goal is to reduce greenhouse gas emissions 30% by 2020 and 100% by 2050. In addition to emissions reduction, the Climate Action Plan articulates goals for embedding sustainability into the curricular and co-curricular aspects of a Richmond education. The plan has been developed under the leadership of the Sustainability Working Group and the University’s Sustainability Coordinator. Climate Action Plan subgroups, with representation of staff, faculty, and students, drafted …

Go to article

Metastable Anions Of Dinitrobenzene: Resonances For Electron Attachment And Kinetic Energy Release, A. Mauracher, S. Denifl, A. Edtbauer, M. Hager, M. Probst, Olof E. Echt, T. D. Maerk, P. Scheier, T. A. Field, K. Graupner Dec 2010

Metastable Anions Of Dinitrobenzene: Resonances For Electron Attachment And Kinetic Energy Release, A. Mauracher, S. Denifl, A. Edtbauer, M. Hager, M. Probst, Olof E. Echt, T. D. Maerk, P. Scheier, T. A. Field, K. Graupner

Physics & Astronomy

Attachment of free, low-energy electrons to dinitrobenzene (DNB) in the gas phase leads to DNB as well as several fragment anions. DNB, (DNB-H), (DNB-NO), (DNB-2NO), and (DNB-NO(2)) are found to undergo metastable (unimolecular) dissociation. A rich pattern of resonances in the yield of these metastable reactions versus electron energy is observed; some resonances are highly isomer-specific. Most metastable reactions are accompanied by large average kinetic energy releases (KER) that range from 0.5 to 1.32 eV, typical of complex rearrangement reactions, but (1,3-DNB-H)(-) features a resonance with a KER of only 0.06 eV for loss of NO. (1,3-DNB-NO)(-) offers a rare …

Go to article

Pitch Angle Scattering In The Outer Heliosheath And Formation Of The Interstellar Boundary Explorer Ribbon, Konstantin V. Gamayunov, Ming Zhang, Hamid K. Rassoul Dec 2010

Pitch Angle Scattering In The Outer Heliosheath And Formation Of The Interstellar Boundary Explorer Ribbon, Konstantin V. Gamayunov, Ming Zhang, Hamid K. Rassoul

Aerospace, Physics, and Space Science Faculty Publications

The dominant and unexpected feature in the first Interstellar Boundary EXplorer (IBEX) maps is a ribbon of the enhanced energetic neutral atom (ENA) emissions. Presenting the first results from IBEX,McComas et al. identified six possible mechanisms of ribbon formation. One of the mechanisms, the so-called secondary ENA mechanism, was already quantitatively elaborated by Heerikhuisen et al., and they successfully reproduced the main features of the ribbon. We further study the "secondary ENA" mechanism by quantifying a previously omitted stage of the proton evolution between two consecutive acts of the charge-exchange in the outer heliosheath (OHS). The main findings can be …

Go to article

Pitch Aangle Scattering In The Outer Heliosheath And Formation Of The Interstellar Boundary Explorer Ribbon, Konstantin V. Gamayunov, Ming Zhang, Hamid K. Rassoul Dec 2010

Pitch Aangle Scattering In The Outer Heliosheath And Formation Of The Interstellar Boundary Explorer Ribbon, Konstantin V. Gamayunov, Ming Zhang, Hamid K. Rassoul

Aerospace, Physics, and Space Science Faculty Publications

The dominant and unexpected feature in the first Interstellar Boundary EXplorer (IBEX) maps is a ribbon of the enhanced energetic neutral atom (ENA) emissions. Presenting the first results from IBEX,McComas et al. identified six possible mechanisms of ribbon formation. One of the mechanisms, the so-called secondary ENA mechanism, was already quantitatively elaborated by Heerikhuisen et al., and they successfully reproduced the main features of the ribbon. We further study the "secondary ENA" mechanism by quantifying a previously omitted stage of the proton evolution between two consecutive acts of the charge-exchange in the outer heliosheath (OHS). The main findings can be …

Go to article

Precision Frequency Measurements With Interferometric Weak Values, David J. Starling, P. Ben Dixon, Andrew N. Jordan, John C. Howell Dec 2010

Precision Frequency Measurements With Interferometric Weak Values, David J. Starling, P. Ben Dixon, Andrew N. Jordan, John C. Howell

Mathematics, Physics, and Computer Science Faculty Articles and Research

We demonstrate an experiment which utilizes a Sagnac interferometer to measure a change in optical frequency of 129 ± 7 kHz/√Hz with only 2 mW of continuous-wave, single-mode input power. We describe the measurement of a weak value and show how even higher-frequency sensitivities may be obtained over a bandwidth of several nanometers. This technique has many possible applications, such as precision relative frequency measurements and laser locking without the use of atomic lines.

Go to article

Exploring Sustainable Environmental Management Practices For Golf Courses In Semi-Arid Environments, Angelica V. Gurule Dec 2010

Exploring Sustainable Environmental Management Practices For Golf Courses In Semi-Arid Environments, Angelica V. Gurule

Masters Theses, 2010-2019

For the past several years NM government officials have been working to increase economic growth via tourism in NM. As a result several dozen golf courses have popped up around the state. Golf courses are conceived to be problematic as they consume large quantities of water and typically use lots of harmful pesticides to manage turfgrass. Water scarcity has already shown its face in NM: there are drought plans in place and growing evidence that illustrates the decrease in precipitation and an increase in temperatures, which will further reduce water resources. The scope of this paper is to analyze the …

Go to article

Implementation Of The Clas12 Htcc Into Gemc, Nathan A. Harrison Dec 2010

Implementation Of The Clas12 Htcc Into Gemc, Nathan A. Harrison

Master's Theses

No abstract provided.

Go to article

An Investigation Of How Surface Coal Mining Affects Water Quality., Sara Moore Dec 2010

An Investigation Of How Surface Coal Mining Affects Water Quality., Sara Moore

Undergraduate Honors Theses

Surface coal mining has become the ideal method for extracting coal from the Appalachia Mountains. However, surface coal mining generates large amounts of waste which may decrease the water quality in central Appalachia. This research is an attempt to determine whether surface coal mining negatively impacts water quality. This research consists of a literature review in addition to an analysis of data obtained through the Virginia Department of Environmental Quality. This data was analyzed at three separate locations along the Clinch River, VA to determine trends and cycles in pH, temperature, total hardness, and chloride, sulfate and metal concentrations. After …

Go to article

Transport Of Nordic Seas Overflow Water Into And Within The Irminger Sea: An Eddy-Resolving Simulation And Observations, Xiaobiao Xu, W.J. Schmitz Jr., Harley E. Hulbert, Patrick J. Hogan, Eric P. Chassignet, H.M. Van Aken Dec 2010

Transport Of Nordic Seas Overflow Water Into And Within The Irminger Sea: An Eddy-Resolving Simulation And Observations, Xiaobiao Xu, W.J. Schmitz Jr., Harley E. Hulbert, Patrick J. Hogan, Eric P. Chassignet, H.M. Van Aken

Faculty Publications

Results from a climatologically forced, eddy-resolving (1/12 degrees) Atlantic simulation using the Hybrid Coordinate Ocean Model help clarify some presently unresolved connections between volume transports of Nordic Seas overflow water at key locations in the northernmost North Atlantic Ocean. The model results demonstrate that, in addition to the known westward flow through the Charlie Gibbs Fracture Zone (CGFZ), some Iceland Scotland overflow water (ISOW) flows westward through gaps in the Reykjanes Ridge north of the CGFZ into the Irminger Sea, and some flows southward along the eastern flank of the Mid-Atlantic Ridge into the West European Basin. These results provide …

Go to article

Conjugate Additions And Transposition Of The Allylic Alcohols Of Enol Ethers Of 1, 2-Cyclohexanedione., Barnabas Otoo Dec 2010

Conjugate Additions And Transposition Of The Allylic Alcohols Of Enol Ethers Of 1, 2-Cyclohexanedione., Barnabas Otoo

Electronic Theses and Dissertations

A variety of protected enolic forms of 1, 2-cyclohexanedione was prepared as substrates for conjugate addition studies using organocopper reagents. The sequence involved the enol ether preparation via the enolate, alkylation with an organometalic reagent, and oxidative rearrangement with pyridinium chlorochromate followed by the conjugate addition reactions. Protection of 1, 2-cyclohexanedione was achieved by reacting with chloro tert-butyldimethyl silane and subjected to alkylation. Steric problems were encountered and so an alternative protective group the methoxymethyl acetal was prepared and studied. Alkylation of these derivatives was successful; however, the oxidation was problematic and although evidence for rearrangement was observed in one …

Go to article

P300-Based Bci Performance Prediction Through Examination Of Paradigm Manipulations And Principal Components Analysis., Nicholas Edward Schwartz Dec 2010

P300-Based Bci Performance Prediction Through Examination Of Paradigm Manipulations And Principal Components Analysis., Nicholas Edward Schwartz

Electronic Theses and Dissertations

Severe neuromuscular disorders can produce locked-in syndrome (LIS), a loss of nearly all voluntary muscle control. A brain-computer interface (BCI) using the P300 event-related potential provides communication that does not depend on neuromuscular activity and can be useful for those with LIS. Currently, there is no way of determining the effectiveness of P300-based BCIs without testing a person's performance multiple times. Additionally, P300 responses in BCI tasks may not resemble the typical P300 response. I sought to clarify the relationship between the P300 response and BCI task parameters and examine the possibility of a predictive relationship between traditional oddball tasks …

Go to article

The Correlation Of The Concentration Of Selected Metals Determined In Water And Fish Samples From A Public Pond., Paula Kay Edwards Dec 2010

The Correlation Of The Concentration Of Selected Metals Determined In Water And Fish Samples From A Public Pond., Paula Kay Edwards

Electronic Theses and Dissertations

The concentrations of heavy metals (Cd, Cu, Fe, Ni, Pb, Zn) were measured in water, and fish samples caught from the pond at Fishery Park in Unicoi County, TN. The water samples were collected once a week for 8 weeks. The amounts of metals in the muscle tissues, gill, and liver of the two fish species were measured. This was to determine if any correlation exists between the metal contents in water and those in the fish samples. The concentration ranges for the heavy metals found in the water samples are as follows: Zn 0.04-0.13; Cu, 0.00-0.00; Pb, 0.00-0.59; Cd, …

Go to article

A Landscape Assessment Study Of The South Gozo Fault Area, Mariella Xuereb Dec 2010

A Landscape Assessment Study Of The South Gozo Fault Area, Mariella Xuereb

Masters Theses, 2010-2019

The South Gozo Fault region features a heterogeneous landscape which extends from Ras il-Qala on the east, to „Mgarr ix-Xini‟ on the south-eastern littoral. In recent decades, parts of this region have experienced substantial levels of development while others remain untouched. This study seeks to explore the impact of existing and proposed development projects on the character and value of the South Gozo Fault landscape. A landscape character assessment, together with an assessment of the value of the landscape will be conducted, with the aim of analyzing the present character and value of the landscape, and comparing this with the …

Go to article

Integrated Waste Management In Malta-Future Scenario Development, Ruth Debrincat Dec 2010

Integrated Waste Management In Malta-Future Scenario Development, Ruth Debrincat

Masters Theses, 2010-2019

Waste management is recognised as a major international environmental challenge since it is considered to be the loss of environmental resources. The Sixth Environment Action Programme (European Commission) calls for a cultural shift towards sustainable consumption patterns to bring about a reduction in waste generation. In Malta, the scale of waste generation, presently at 648 kg per capita (MEPA, 2008), and the need for sustainable waste management policies are of particular concern. The main objective of this dissertation was to adopt a systems view to evaluate the current status of integrated waste management in Malta and anticipate possible solutions in …

Go to article

A Comparative Social, Economic And Environmental Study Of How Malta Could Best Achieve Its 2020 “20-20-20” Goals, Charles G. Sinn Dec 2010

A Comparative Social, Economic And Environmental Study Of How Malta Could Best Achieve Its 2020 “20-20-20” Goals, Charles G. Sinn

Masters Theses, 2010-2019

The European Union has recognized the need for an action plan to facilitate the gradual transition to a dominant, renewable energy production base for the myriad of benefits that renewable over non-renewable production brings. Malta, as a member of the EU, is obliged to achieve nationwide goals as specified in the Renewable Energy Directive with regards to electrical efficiency, carbon emissions and renewable energy production share. The goals for Malta include an achievement by 2020 of a 10 % renewable production base, a 10 % electrical efficiency improvement and an allowance for a 5 % increase in carbon emissions as …

Go to article

Extraction And Determination Of A Selected Polyphenol From Selected Red And Black Grapes By High Performance Liquid Chromatography., Summer Nicole Niles Dec 2010

Extraction And Determination Of A Selected Polyphenol From Selected Red And Black Grapes By High Performance Liquid Chromatography., Summer Nicole Niles

Undergraduate Honors Theses

Polyphenols are a group of compounds found naturally in plants and they provide much of the flavor, color, and taste to fruits, vegetables, seeds, and other parts of the plants They also act as antioxidants which provide numerous health benefits by protecting cells against damage caused by free radicals. Their antibacterial, anti-inflammatory and anti-allergenic properties have also contributed to the prevention of degenerative diseases, such as cardiovascular diseases and cancers by slowing the rate of oxidative stress on cells. This study was aimed at the identification and quantitation of a specific polyphenol, quercetin, found in grapes commonly purchased at grocery …

Go to article

Identifying Landscape Quality Objectives For Gozo, Stephanie Farrugia Dec 2010

Identifying Landscape Quality Objectives For Gozo, Stephanie Farrugia

Masters Theses, 2010-2019

The study of landscape quality has not been researched to a significant degree in Malta to date. This qualitative study explores different viewpoints in relation to perceptions of landscape quality, at present and in the future, on the island of Gozo, based on provisions of the European Landscape Convention. The latter, to which Malta is a signatory state, calls for the identification of landscape quality objectives, which should reflect public aspirations. Primary data collection methods, comprising community focus groups and key informant semi-structured interviews were used, together with an extensive document analysis, to understand a range of perceptions of present …

Go to article

Assessing The Potential Benefits Of Learning About Environmental Issues Through A Systems Thinking Pedagogy, Abigail Noble Graefe Dec 2010

Assessing The Potential Benefits Of Learning About Environmental Issues Through A Systems Thinking Pedagogy, Abigail Noble Graefe

Masters Theses, 2010-2019

Systems thinking is a fundamental learning methodology in sustainability education and in some K-12 standards-based education systems in the United States. However, there is little research and practical application on the use of systems thinking in environmental education, especially at the elementary level. This thesis uses a case study on climate change to assess whether a pedagogy based on systems thinking can fulfill learning objectives derived from the Illinois Learning Standards for Science (ILSS) and provide further insights and understandings on the subject being studied. Three learning modules on climate change consisting of systems thinking habits of mind, concepts, and …

Go to article

Assessing Vulnerability To Coastal Hazards Case Study: Gozo, Jonathan Portelli Dec 2010

Assessing Vulnerability To Coastal Hazards Case Study: Gozo, Jonathan Portelli

Masters Theses, 2010-2019

All coastal areas around the globe are vulnerable to a series of potential hazards at different degrees depending on location, altitude above sea level, geomorphological features and socio-economic factors, including demography, human settlement and infrastructural development. Since the 1990s a major effort in developing appropriate methodologies and guidelines to assess coastal vulnerability has been made. Of significant importance, the coast of Gozo embraces both natural and anthropogenic features that occupy a relatively small area. Consequently, coastal vulnerability by multiple coastal hazards is a fact due to the topography of the island, overpopulation in some coastal locations, and intensive coastal development …

Go to article

A Heuristic For Local Land Planning: Linking Ecological Function And Policy-In Context To Charlotte, North Carolina-, Kimberlee Robertella Dec 2010

A Heuristic For Local Land Planning: Linking Ecological Function And Policy-In Context To Charlotte, North Carolina-, Kimberlee Robertella

Masters Theses, 2010-2019

Ecological systems and services are foundational to human well-being, and in recent years have received increasing scholastic attention. The functional ability of these systems is influenced however, by human-induced land transformation related to conventional patterns of growth and development. Such land transformations, which commonly occur as single-family residential development, are criticized as being wasteful and inefficient, leading to issues like air and water pollution, diminished forests and wetlands, and habitat loss and fragmentation. In the United States a patchwork of policy exists aimed at addressing such ecological concerns. Despite best efforts, most local governments and planning offices still miss the …

Go to article

A Preliminary Assessment Of The Long-Term Prospects For Offshore Wind Farms In Maltese Territorial Waters, Dane Orion Zammit Dec 2010

A Preliminary Assessment Of The Long-Term Prospects For Offshore Wind Farms In Maltese Territorial Waters, Dane Orion Zammit

Masters Theses, 2010-2019

Almost all of Malta’s current interest in offshore wind development is focused on the development of an offshore wind farm at Sikka L-Bajda in northwest Malta by 2020, to help the country reach its mandated 2020 RES target. The offshore wind industry is rapidly gaining momentum, with larger projects in deeper waters further offshore being commissioned every year. Countries like Germany and the United Kingdom have actively constructed, or are planning to construct, offshore wind farms at transitional water depths before 2020. The offshore wind energy market has historically been restricted to the North Sea, the Baltic Sea and the …

Go to article

The Sir Model When S(T) Is A Multi-Exponential Function., Teshome Mogessie Balkew Dec 2010

The Sir Model When S(T) Is A Multi-Exponential Function., Teshome Mogessie Balkew

Electronic Theses and Dissertations

The SIR can be expressed either as a system of nonlinear ordinary differential equations or as a nonlinear Volterra integral equation. In general, neither of these can be solved in closed form. In this thesis, it is shown that if we assume S(t) is a finite multi-exponential, i.e. function of the form S(t) = a+ ∑nk=1 rke-σkt or a logistic function which is an infinite-multi-exponential, i.e. function of the form S(t) = c + a/b+ewt, then …

Go to article

Predicting Treatment Efficacy Via Quantitative Mri: A Bayesian Joint Model, Jincao Wu, Tim Johnson Dec 2010

Predicting Treatment Efficacy Via Quantitative Mri: A Bayesian Joint Model, Jincao Wu, Tim Johnson

The University of Michigan Department of Biostatistics Working Paper Series

The prognosis for patients with high-grade gliomas is poor, with a median survival of one year. Treatment efficacy assessment is typically unavailable until 5{6 months post diagnosis. Investigators hypothesize that quantitative MRI (qMRI) can assess treatment efficacy three weeks after therapy starts, thereby allowing salvage treatments to begin earlier. The purpose of this work is to build a predictive model of treatment efficacy using qMRI data and to assess its performance. The outcome is one-year survival status. We propose a joint, two-stage Bayesian model. In stage I, we smooth the image data with a multivariate spatio-temporal pairwise dierence prior. We …

Go to article

Efficient Measurement Error Correction With Spatially Misaligned Data, Adam A. Szpiro, Lianne Sheppard, Thomas Lumley Dec 2010

Efficient Measurement Error Correction With Spatially Misaligned Data, Adam A. Szpiro, Lianne Sheppard, Thomas Lumley

UW Biostatistics Working Paper Series

Association studies in environmental statistics often involve exposure and outcome data that are misaligned in space. A common strategy is to employ a spatial model such as universal kriging to predict exposures at locations with outcome data and then estimate a regression parameter of interest using the predicted exposures. This results in measurement error because the predicted exposures do not correspond exactly to the true values. We characterize the measurement error by decomposing it into Berkson-like and classical-like components. One correction approach is the parametric bootstrap, which is effective but computationally intensive since it requires solving a nonlinear optimization problem …

Go to article

First Prev Next Last