Physical Sciences and Mathematics Commons^™

Analysis Of The Peerrank Method For Peer Grading, Joshua Kline

Honors Theses

Peer grading can have many benefits in education, including a reduction in the time instructors spend grading and an opportunity for students to learn through their analysis of others work. However, when not handled properly, peer grading can be unreliable and may result in grades that are vastly different from those which a student truly deserves. Therefore, any peer grading system used in a classroom must consider the potential for graders to generate inaccurate grades. One such system is the PeerRank rule proposed by Toby Walsh, which uses an iterative, linear algebra based process reminiscent of the Google PageRank algorithm …

Annealing 2-Decanol In Nano-Confined Systems: Effects Of Annealing Time, Caleb Novins

Honors Theses

We studied melting and freezing of 2-decanol nano-crystals (100 Angstrom to 1000 Angstrom) using a Differential Scanning Calorimeter (DSC). In agreement with the Gibbs-Thompson equation, the melting temperature of nano crystals decreases with physical size and its change scales linearly with the inverse of physical size. The apparent heat of fusion of the nano scaled systems, however, has been found to be lower than the heat of fusion for the bulk. Although this is in agreement with previous experimental observations, it is in contradiction with the assumptions used to develop the Gibbs-Thompson equation. We believe that the apparent heat of …

Liftings And Stresses For Planar Periodic Frameworks, Ciprian Borcea, Ileana Streinu

Computer Science: Faculty Publications

We formulate and prove a periodic analog of Maxwell’s theorem relating stressed planar frameworks and their liftings to polyhedral surfaces with spherical topology. We use our lifting theorem to prove rigidity-theoretic properties for planar periodic pseudo-triangulations, generalizing their finite counterparts. These properties are then applied to questions originating in mathematical crystallography and materials science, concerning planar periodic auxetic structures and ultrarigid periodic frameworks.

Why We Need Extra Physical Dimensions: A Simple Geometric Explanation, Olga Kosheleva, Vladik Kreinovich

Departmental Technical Reports (CS)

It is known that a consistent description of point-wise particles requires that we add extra physical dimensions to the usual four dimensions of space-time. The need for such dimensions is based on not-very-intuitive complex mathematics. It is therefore desirable to try to come up with a simpler geometric explanation for this phenomenon. In this paper, we provide a simple geometric explanation of why extra physical dimensions are needed.

How To Gauge Disruptions Caused By Garbage Collection: Towards An Efficient Algorithm, Gabriel Arellano, Edward Hudgins, David Pruitt, Adrian Veliz, Eric Freudenthal, Vladik Kreinovich

Departmental Technical Reports (CS)

Comprehensive garbage collection is employed on a variety of computing devices, including intelligent cell phones. Garbage collection can cause prolonged user-interface pauses. In order to evaluate and compare the disruptiveness of various garbage collection strategies, it is necessary to gauge disruptions caused by garbage collection. In this paper, we describe efficient algorithms for computing metrics useful for this purpose.

The Effect Of The El Nino-Southern Oscillation On U.S. Regional And Coastal Sea Level, B. D. Hamlington, R. R. Leben, K. -Y. Kim, R. S. Nerem, L. P. Atkinson, P. R. Thompson

CCPO Publications

Although much of the focus on future sea level rise concerns the long-term trend associated with anthropogenic warming, on shorter time scales, internal climate variability can contribute significantly to regional sea level. Such sea level variability should be taken into consideration when planning efforts to mitigate the effects of future sea level change. In this study, we quantify the contribution to regional sea level of the El Niño-Southern Oscillation (ENSO). Through cyclostationary empirical orthogonal function analysis (CSEOF) of the long reconstructed sea level data set and of a set of U.S. tide gauges, two global modes dominated by Pacific Ocean …

Lessons From Pollution Control: Response To Heller And Hobbs 2014, Robert L. Fischman, James Salzman

Articles by Maurer Faculty

Heller and Hobbs (2014) provide an incisive analysis of the challenges inherent in setting endpoint states as conservation goals. The social construct of nature, nonequilibrium ecosystems, global climate change, large-scale transformations of the landscape, and increasing population and economic activity confound efforts to establish conservation goals. Stakeholders often disagree on endpoint targets, whereas competing notions of historic fidelity and future flexibility frustrate our ability to articulate success, never mind actually achieve it. As Heller and Hobbs describe, this leaves managers in the bind of finding the “balance between future-looking management emphasizing change and past-looking management emphasizing persistence.” As a result, …

Erratum: Theoretical And Experimental (E,2e) Study Of Electron-Impact Ionization Of Laser-Aligned Mg Atoms [Physical Review A 90, 062707 (2014)], Sadek Amami, Andrew J. Murray, Al Stauffer, Kate Nixon, Gregory Armstrong, James Colgan, Don H. Madison

Physics Faculty Research & Creative Works

We have recently reported a theoretical and experimental study of electron-impact ionization of laser-aligned magnesium. Results were presented for both ionization of the ground state, as well as for laser-aligned atoms in the 3p state. For ionization from the 3p state, theoretical results were presented using the distorted wave Born (DWBA) and three-body distorted wave (3DW) approximations. Unfortunately, after publication we learned that the theoretical results were incorrect due to one of the arrays in the computer code dimensioned too small. The figures affected by this error are Figs. 3–5 in the original paper. The present Figs. 3–5 …

Imaging An Aligned Polyatomic Molecule With Laser-Induced Electron Diffraction, Michael G. Pullen, Benjamin Wolter, Anh-Thu Le, Matthias Baudisch, Michael Hemmer, Arne Senftleben, Claus Dieter Schroeter, Joachim Ullrich, Robert Moshammer, C. D. Lin, Jens Biegert

Physics Faculty Research & Creative Works

Laser-induced electron diffraction is an evolving tabletop method that aims to image ultrafast structural changes in gas-phase polyatomic molecules with sub-Ångström spatial and femtosecond temporal resolutions. Here we demonstrate the retrieval of multiple bond lengths from a polyatomic molecule by simultaneously measuring the C-C and C-H bond lengths in aligned acetylene. Our approach takes the method beyond the hitherto achieved imaging of simple diatomic molecules and is based on the combination of a 160kHz mid-infrared few-cycle laser source with full three-dimensional electron-ion coincidence detection. Our technique provides an accessible and robust route towards imaging ultrafast processes in complex gas-phase molecules …

Comparison Of Robotics, Functional Electrical Stimulation, And Motor Learning Methods For Treatment Of Persistent Upper Extremity Dysfunction After Stroke: A Randomized Controlled Trial, Jessica Mccabe, Michelle Monkiewicz, John P. Holcomb, Svetlana Pundik, Janis J. Daly

Mathematics and Statistics Faculty Publications

Objective

To compare response to upper-limb treatment using robotics plus motor learning (ML) versus functional electrical stimulation (FES) plus ML versus ML alone, according to a measure of complex functional everyday tasks for chronic, severely impaired stroke survivors.

Design

Single-blind, randomized trial.

Setting

Medical center.

Participants

Enrolled subjects (N=39) were >1 year post single stroke (attrition rate=10%; 35 completed the study).

Interventions

All groups received treatment 5d/wk for 5h/d (60 sessions), with unique treatment as follows: ML alone (n=11) (5h/d partial- and whole-task practice of complex functional tasks), robotics plus ML (n=12) (3.5h/d of ML and 1.5h/d of shoulder/elbow robotics), …

Umphlett Qci June 2015, Natalie A. Umphlett

High Plains Regional Climate Center: Personnel Publications

Highlights for the Basin

Temperature and Precipitation Anomalies

Drought Conditions

Water Supplies Recovering

Heavy Rains Cause Flooding

Agriculture Impacts

3-Month Precipitation and Temperature Outlooks

Hydrologic Response To Conifer Removal From An Encroached Mountain Meadow, Gregory F. Van Oosbree

Master's Theses

Meadows in the Sierra Nevada Mountains are an important ecological resource that have degraded in quality and distribution due to several environmental and anthropogenic stressors. The encroachment of conifers beyond forest meadow ecotones is largely responsible for the decline of meadow habitat throughout the past century. Currently, there is little research that quantifies the hydrologic response to removal of conifers encroaching meadows in terms of implicating successful meadow restoration. This study has implemented a before after control intervention (BACI) study design to determine the hydrologic response associated with the removal of conifers from a historic meadow encroached by conifers. The …

Imaging The Dipole-Dipole Energy Exchange Between Ultracold Rubidium Rydberg Atoms, Donald P. Fahey, Thomas J. Carroll, Michael W. Noel

Physics and Astronomy Faculty Publications

The long-range, anisotropic nature of the interaction among atoms in an ultracold dipolar gas leads to a rich array of possibilities for studying many-body physics. In this work, an ultracold gas of highly excited atoms is used to study energy transport due to the long-range dipole-dipole interaction. A technique is developed to measure both the internal energy states of the interacting Rydberg atoms and their positions in space. This technique is demonstrated by observing energy exchange between two spatially separated groups of Rydberg atoms excited to two different internal states. Simulations confirm the general features of the energy transport in …

Towards A Physics-Motivated Small-Velocities Approximation To General Relativity, Vladik Kreinovich, Olga Kosheleva

Departmental Technical Reports (CS)

In the general case, complex non-linear partial differential equations of General Relativity are very hard to solve. Thus, to solve the corresponding physical problems, usually appropriate approximations are used. The first approximation to General Relativity is, of course, Newton's theory of gravitation. Newton's theory is applicable when the gravitational field is weak and when all velocities are much smaller than the speed of light. Most existing approximations allow higher velocities, but still limit us to weak gravitational fields. In this paper, he consider the possibility of a different approximation, in which strong fields are allowed but velocities are required to …

Method For Matching Probabilistic Encrypted Data, Hwee Hwa Pang, Xuhua Ding

Research Collection School Of Computing and Information Systems

Determining if a first encrypted data of a first data value is equal to a second encrypted data of a second data value. Comprising: a first cyclic group; a second cyclic group including a first element. Applying an operation to the first cyclic group to map its elements to an element in the second cyclic group. Randomly selecting a second element from the first cyclic group; producing the first encrypted data by mapping the second element and the first data value into one or more elements of the first cyclic group. Randomly selecting a third element from the first cyclic …

Supramolecular Approaches To Nanoscale Morphological Control In Organic Solar Cells, Alexander M. Haruk, Jeffrey M. Mativetsky

Physics, Applied Physics and Astronomy Faculty Scholarship

Having recently surpassed 10% efficiency, solar cells based on organic molecules are poised to become a viable low-cost clean energy source with the added advantages of mechanical flexibility and light weight. The best-performing organic solar cells rely on a nanostructured active layer morphology consisting of a complex organization of electron donating and electron accepting molecules. Although much progress has been made in designing new donor and acceptor molecules, rational control over active layer morphology remains a central challenge. Long-term device stability is another important consideration that needs to be addressed. This review highlights supramolecular strategies for generating highly stable nanostructured …

Investigations Into Non-Degenerate Quasihomogeneous Polynomials As Related To Fjrw Theory, Scott C. Mancuso

Theses and Dissertations

The motivation for this paper is a better understanding of the basic building blocks of FJRW theory. The basics of FJRW theory will be briefly outlined, but the majority of the paper will deal with certain multivariate polynomials which are the most fundamental building blocks in FJRW theory. We will first describe what is already known about these polynomials and then discuss several properties we proved as well as conjectures we disproved. We also introduce a new conjecture suggested by computer calculations performed as part of our investigation.

Using Declassified Satellite Imagery To Quantify Geomorphic Change: A New Approach And Application To Himalayan Glaciers, Joshua Michael Maurer

Theses and Dissertations

Himalayan glaciers are key components of earth's cryosphere, acting as hydrological reservoirs vital to many human and natural systems. Most Himalayan glaciers are shrinking in response to changing climate, which will potentially impact water resources, natural hazards, sea level rise, and many other aspects. However, there is much uncertainty regarding the state of these glaciers, as direct field data are difficult to obtain. Accordingly, long-timespan remote sensing techniques are needed to measure changing glaciers, which have memory and often respond to climate on decadal timescales. This study uses declassified historical imagery from the Hexagon spy satellite database to fulfill this …

A Models And Modeling Approach To Risk And Uncertainty, Corey Brady, Richard Lesh

The Mathematics Enthusiast

In this article we describe potential contributions of a Models and Modeling Perspective to research focused on learners’ developing conceptions about uncertainty and variation. In particular, we show how a particular class of realistic problem-solving tasks can illuminate how learners develop models to identify, describe, and predict emergent patterns of regularity in the behavior of various types of systems and in the data these systems generate. We begin by situating current design work in this area within a larger project to investigate idea development in the domain of data modeling over extended (course-length) periods. We give design principles and examples …

Calculated Risks: The Teacher As Big Data Producer And Risk Analyst, Nat Banting

The Mathematics Enthusiast

Teachers’ work is often subjected to data analysis from outside sources in the forms of standardized examinations and media critique. This article uses the literature of risk analysis to play with two important analogies for teachers with regards to the emerging big data culture and the risk decisions therein. The complex context of the classroom facilitates the exploration of teacher as big data producer, while the multi-faceted nature of risk decisions provide the groundwork for the exploration of teacher as risk analyst. Illustrative classroom episodes portray examples of real and virtual risk faced by teachers, and a third category—curricular risk—is …

Service Quality And Perceived Value Of Cloud Computing-Based Service Encounters: Evaluation Of Instructor Perceived Service Quality In Higher Education In Texas, Eges Egedigwe

CCE Theses and Dissertations

Cloud computing based technology is becoming increasingly popular as a way to deliver quality education to community colleges, universities and other organizations. At the same time, compared with other industries, colleges have been slow on implementing and sustaining cloud computing services on an institutional level because of budget constraints facing many large community colleges, in addition to other obstacles. Faced with this challenge, key stakeholders are increasingly realizing the need to focus on service quality as a measure to improve their competitive position in today's highly competitive environment. Considering the amount of study done with cloud computing in education, very …

Emerging Criticality In The Disordered Three-Color Ashkin-Teller Model, Qiong Zhu, Xin Wan, Rajesh Narayanan, José A. Hoyos, Thomas Vojta

Physics Faculty Research & Creative Works

We study the effects of quenched disorder on the first-order phase transition in the two-dimensional three-color Ashkin-Teller model by means of large-scale Monte Carlo simulations. We demonstrate that the first-order phase transition is rounded by the disorder and turns into a continuous one. Using a careful finite-size-scaling analysis, we provide strong evidence for the emerging critical behavior of the disordered Ashkin-Teller model to be in the clean two-dimensional Ising universality class, accompanied by universal logarithmic corrections. This agrees with perturbative renormalization-group predictions by Cardy. As a byproduct, we also provide support for the strong-universality scenario for the critical behavior of …

Repcoin: The Only Reputation Market, Matthew Ritter

Dartmouth College Undergraduate Theses

With the internet taking over as a one-stop shop for information, finding credible material is becoming difficult. People look increasingly to the web to satisfy their questions along with their professional and entertainment needs. For the content seeker, the right content can be hard to find. Forums are cluttered with unreliable answers, entertainment sites overflow with mediocre artists, and professional searches yield countless novices. For the content creator, building a credible online presence is also difficult. Bloggers and professionals can be drowned out by similar candidates. Repcoin attempts to alleviate problems for both the content creator and the content seeker …

Wiprint: 3d Printing Your Wireless Coverage, Justin Chan

Dartmouth College Undergraduate Theses

Wireless signals are everywhere in residential, commercial and industrial environments. Directing wireless signals to conform to custom physical boundaries is of great importance in improving the performance, security and privacy of a wireless system. Unfortunately current solutions like directional antennas are bulky and expensive for ordinary users. We propose WiPrint, a novel approach to customizing wireless signal maps using 3D printed glossy reflectors. This solution is easily manufactured and adapts easily to different environments. The WiPrint system is highly flexible as it does not require adding additional APs or moving the AP to new locations. This is significant in the …

Hurricanes And Climate The U.S. Clivar Working Group On Hurricanes, Kevin J.E. Walsh, Suzana J. Camargo, Gabriel A. Vecchi, Anne Sophie Daloz, James Elsner, Kerry Emanuel, Michael Horn, Young-Kwon Lim, Malcom Roberts, Christina Patricola, Enrico Scoccimarro, Adam H. Sobel, Sarah Strazzo, Gabrielle Villarini, Michael Wehner, Ming Zhao, James P. Kossin, Tim Larow, Kazuyoshi Oouchi, Sigfried Schubert, Hui Wang, Julio Bacmeister, Ping Chang, Fabrice Chauvin, Christiane Jablonowski, Arun Kumar, Hiroyuki Murakami, Tomoaki Ose, Kevin A. Reed, Ramalingam Saravanan, Yohei Yamada, Colin M. Zarzycki, Pier Luigi Vidale, Jefferey A. Jonas, Naomi Henderson

Publications

While a quantitative climate theory of tropical cyclone formation remains elusive, considerable progress has been made recently in our ability to simulate tropical cyclone climatologies and to understand the relationship between climate and tropical cyclone formation. Climate models are now able to simulate a realistic rate of global tropical cyclone formation, although simulation of the Atlantic tropical cyclone climatology remains challenging unless horizontal resolutions finer than 50 km are employed. This article summarizes published research from the idealized experiments of the Hurricane Working Group of U.S. Climate and Ocean: Variability, Predictability and Change (CLIVAR). This work, combined with results from …

Multiphysics Modeling To Enhance Understanding Of Microwave Heating Of Food In Domestic Ovens, Jiajia Chen

Department of Biological Systems Engineering: Dissertations and Theses

Nonuniform heating is the biggest issue in the microwave heating of prepared meals. Multiphysics based models are promising tools to improve microwave heating uniformity by properly designing the food product. However, limited availability of accurate temperature-dependent material properties, inadequate model prediction accuracy, and high computational power and complexity in model development are three gaps that greatly limited the application of these models in the food industry.

To fill in the gaps, firstly, we developed a multitemperature calibration protocol to measure temperature-dependent dielectric properties (dielectric constant and loss factor). The temperature-dependent dielectric and thermal (thermal conductivity and specific heat capacity) properties …

Adaptive Resource Provisioning Mechanism In Vees For Improving Performance Of Hla-Based Simulations, Zengxiang Li, Wentong Cai, Stephen John Turner, Xiaorong Li, Nguyen Binh Duong Ta

Research Collection School Of Computing and Information Systems

Parallel and distributed simulations (or High-Level Architecture (HLA)-based simulations) employing optimistic synchronization allow federates to advance simulation time freely at the risk of overoptimistic executions and execution rollbacks. As a result, the simulation performance may degrade significantly due to the simulation workload imbalance among federates. In this article, we investigate the execution of parallel and distributed simulations on Cloud and data centers with Virtual Execution Environments (VEEs). In order to speed up simulation execution, an Adaptive Resource Provisioning Mechanism in Virtual Execution Environments (ArmVee) is proposed. It is composed of a performance monitor and a resource manager. The former measures …

Replica Placement For Availability In The Worst Case, Peng Li, Debin Gao, Mike Reiter

Research Collection School Of Computing and Information Systems

We explore the problem of placing object replicas on nodes in a distributed system to maximize the number of objects that remain available when node failures occur. In our model, failing (the nodes hosting) a given threshold of replicas is sufficient to disable each object, and the adversary selects which nodes to fail to minimize the number of objects that remain available. We specifically explore placement strategies based on combinatorial structures called t-packings; provide a lower bound for the object availability they offer; show that these placements offer availability that is c-competitive with optimal; propose an efficient algorithm for computing …

Author Topic Model-Based Collaborative Filtering For Personalized Poi Recommendations, Shuhui Jiang, Xueming Qian, Jialie Shen, Yun Fu, Tao Mei

Research Collection School Of Computing and Information Systems

From social media has emerged continuous needs for automatic travel recommendations. Collaborative filtering (CF) is the most well-known approach. However, existing approaches generally suffer from various weaknesses. For example, sparsity can significantly degrade the performance of traditional CF. If a user only visits very few locations, accurate similar user identification becomes very challenging due to lack of sufficient information for effective inference. Moreover, existing recommendation approaches often ignore rich user information like textual descriptions of photos which can reflect users' travel preferences. The topic model (TM) method is an effective way to solve the "sparsity problem," but is still far …

Wifi-Based Indoor Line-Of-Sight Identification, Zimu Zhou, Zheng Yang, Chenshu Wu, Longfei Shangguan, Haibin Cai, Yunhao Liu, Lionel M. Ni

Research Collection School Of Computing and Information Systems

Wireless LANs, particularly WiFi, have been pervasively deployed and have fostered myriad wireless communication services and ubiquitous computing applications. A primary concern in designing these applications is to combat harsh indoor propagation environments, particularly Non-Line-Of-Sight (NLOS) propagation. The ability to identify the existence of the Line-Of-Sight (LOS) path acts as a key enabler for adaptive communication, cognitive radios, and robust localization. Enabling such capability on commodity WiFi infrastructure, however, is prohibitive due to the coarse multipath resolution with MAC-layer received signal strength. In this paper, we propose two PHY-layer channel-statistics-based features from both the time and frequency domains. To further …