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Articles 1 - 30 of 482

Full-Text Articles in Physical Sciences and Mathematics

A Model For The Spread Of Infectious Diseases In A Region, Elizabeth Hunter, Brian Mac Namee, John D. Kelleher Apr 2020

A Model For The Spread Of Infectious Diseases In A Region, Elizabeth Hunter, Brian Mac Namee, John D. Kelleher

Articles

In understanding the dynamics of the spread of an infectious disease, it is important to understand how a town’s place in a network of towns within a region will impact how the disease spreads to that town and from that town. In this article, we take a model for the spread of an infectious disease in a single town and scale it up to simulate a region containing multiple towns. The model is validated by looking at how adding additional towns and commuters influences the outbreak in a single town. We then look at how the centrality of a ...


Economic Review Of Pasture Development Options For North Australian Beef Enterprises, Neil D. Macleod, Dianne Mayberry, Lindsay Bell, Ian Watson Apr 2020

Economic Review Of Pasture Development Options For North Australian Beef Enterprises, Neil D. Macleod, Dianne Mayberry, Lindsay Bell, Ian Watson

International Grassland Congress Proceedings

Beef cattle grazing (~14 million head) native pastures is the dominant economic use of northern grazing lands (2.3 million km2). Few enterprises make positive economic returns in most years or achieve the necessary productivity gains (~2% per annum) to offset an ongoing cost-price squeeze (McCosker et al., 2010). A significant contributor to poor performance is low reproductive performance, management of first calving heifers, calf growth and weaning rates and liveweight gain - linked to nutrition and the low quality of pastures. Pasture development technologies (Gramshaw and Walker, 1988) are available but uptake has been poor. Three pasture development options offering ...


Improved Modelling Of Lucerne (Medicago Sativa L.) Production For Grazing Livestock, Andrew Smith Apr 2020

Improved Modelling Of Lucerne (Medicago Sativa L.) Production For Grazing Livestock, Andrew Smith

International Grassland Congress Proceedings

Lucerne (or alfalfa; Medicago sativa L.)-based pastures play an important role in livestock and mixed farms (croplivestock) in Australia. If lucerne is to be more widely adopted, it will be important that landholders are able to plan to maximize its benefits to their livestock enterprises (usually as a part of a diverse feed base), as well as assess the benefits and minimizing the costs of lucerne phases to subsequent crops. However, the ability to accurately model lucerne plant physiology across the full spectrum of environments, genotypes and cultivars remains elusive. This study aimed to review and revise the description ...


Estimating Error And Bias In Offline Evaluation Results, Mucun Tian, Michael D. Ekstrand Mar 2020

Estimating Error And Bias In Offline Evaluation Results, Mucun Tian, Michael D. Ekstrand

Computer Science Faculty Publications and Presentations

Offline evaluations of recommender systems attempt to estimate users’ satisfaction with recommendations using static data from prior user interactions. These evaluations provide researchers and developers with first approximations of the likely performance of a new system and help weed out bad ideas before presenting them to users. However, offline evaluation cannot accurately assess novel, relevant recommendations, because the most novel items were previously unknown to the user, so they are missing from the historical data and cannot be judged as relevant.

We present a simulation study to estimate the error that such missing data causes in commonly-used evaluation metrics in ...


Modelling Complex Sheep Systems Using Ausfarm, Susan M. Robertson, Michael A. Friend Jan 2020

Modelling Complex Sheep Systems Using Ausfarm, Susan M. Robertson, Michael A. Friend

International Grassland Congress Proceedings

Simulation modelling can be a valuable method for extrapolating experimental findings to different weather or management conditions. However, most of the decision support tools which are available for sheep grazing systems, for example GrassGro® (Donnelly et al. 1997), are limited to modelling of relatively simple sheep management. This makes validation of simulations against experimental results difficult where management changes from year to year, and where more complex sheep management is used. This study evaluated the use of the AusFarm® decision support tool (Moore et al. 2007) to model a split-joined sheep system, using different ram breeds against experimental results.


Towards Agent-Based Traffic Simulation Using Live Data From Sensors For Smart Cities, Johan Barthelemy, Yan Qian, Pascal Perez Jan 2020

Towards Agent-Based Traffic Simulation Using Live Data From Sensors For Smart Cities, Johan Barthelemy, Yan Qian, Pascal Perez

SMART Infrastructure Facility - Papers

The Smart City and Internet-of-Things revolutions enable the collection of various types of data in real-time through sensors. This data can be used to improve the decision tools and simulations used by city planners. This paper presents a new framework for real-time traffic simulation integrating an agent-based methodology with live CCTV and other sensor data while respecting the privacy regulations. The framework simulates traffic flows of pedestrians, vehicles and bicycles and their interactions. The approach has been applied in Liverpool (NSW, Australia) showing promising preliminary results and can easily ingest additional sensor data, e.g. air quality.


The Trolley Problem In Virtual Reality, Jungsu Pak, Ariane Guirguis, Nicholas Mirchandani, Scott Cummings, Uri Maoz Dec 2019

The Trolley Problem In Virtual Reality, Jungsu Pak, Ariane Guirguis, Nicholas Mirchandani, Scott Cummings, Uri Maoz

Student Scholar Symposium Abstracts and Posters

Would people react to the Trolley problem differently based on the medium? Immersive Virtual Reality Driving Simulator was used to examine participants respond to the trolley problem in a realistic and controlled simulated environment.


Exploration Of Nucleic Acid Hydrogran Bonding Using Molecular Mechanics And Dft Calculations, Simi Kaur Dec 2019

Exploration Of Nucleic Acid Hydrogran Bonding Using Molecular Mechanics And Dft Calculations, Simi Kaur

Biological Sciences

Many recent theoretical and experimental techniques have been developed to probe the structurefunction relationships of complex biomolecules. The roles of RNAs are dependent upon various intricate structural motifs and interactions, including hairpins, pseudoknots, long range territory contacts, bulges and internal loops, that are not easily captured by these methods. We had previously developed an enhanced replica exchange molecular dynamics method that incorporated secondary structure information in the form of distance restraints in order to effectively overcome kinetic barriers and sample conformational space. In several structures, restrained RNA base pairs near large bulges displayed a preference for stacking over hydrogen bonding ...


Domain Adaptation In Unmanned Aerial Vehicles Landing Using Reinforcement Learning, Pedro Lucas Franca Albuquerque Dec 2019

Domain Adaptation In Unmanned Aerial Vehicles Landing Using Reinforcement Learning, Pedro Lucas Franca Albuquerque

Computer Science and Engineering: Theses, Dissertations, and Student Research

Landing an unmanned aerial vehicle (UAV) on a moving platform is a challenging task that often requires exact models of the UAV dynamics, platform characteristics, and environmental conditions. In this thesis, we present and investigate three different machine learning approaches with varying levels of domain knowledge: dynamics randomization, universal policy with system identification, and reinforcement learning with no parameter variation. We first train the policies in simulation, then perform experiments both in simulation, making variations of the system dynamics with wind and friction coefficient, then perform experiments in a real robot system with wind variation. We initially expected that providing ...


A Collaborative Visual Localization Scheme For A Low-Cost Heterogeneous Robotic Team With Non-Overlapping Perspectives, Benjamin Abruzzo, David Cappelleri, Philippos Mordohai Nov 2019

A Collaborative Visual Localization Scheme For A Low-Cost Heterogeneous Robotic Team With Non-Overlapping Perspectives, Benjamin Abruzzo, David Cappelleri, Philippos Mordohai

West Point Research Papers

This paper presents and evaluates a relative localization scheme for a heterogeneous team of low-cost mobile robots. An error-state, complementary Kalman Filter was developed to fuse analytically-derived uncertainty of stereoscopic pose measurements of an aerial robot, made by a ground robot, with the inertial/visual proprioceptive measurements of both robots. Results show that the sources of error, image quantization, asynchronous sensors, and a non-stationary bias, were sufficiently modeled to estimate the pose of the aerial robot. In both simulation and experiments, we demonstrate the proposed methodology with a heterogeneous robot team, consisting of a UAV and a UGV tasked with ...


The Impact Of Protostellar Feedback On Astrochemistry, Brandt Gaches Oct 2019

The Impact Of Protostellar Feedback On Astrochemistry, Brandt Gaches

Doctoral Dissertations

Star formation is the lynch pin that lies in between the scales of galaxy and planet formation. Observational studies of molecular clouds, the sites of star formation, primarly use molecular line emission, providing dynamical and chemical information. Two of the key parameters of astrochemical models are far-ultraviolet (FUV) flux and the cosmic ray ionization rate. We use analytic accretion histories to predict the bolometric and FUV luminosities of protostar clusters and compare different histories with observed bolometric luminosities. We find that the Tapered Turbulent Core model best represents the observed luminosities and their dispersion. We extend the models to calculate ...


Development Of An Autonomous Aerial Toolset For Agricultural Applications, Terrance Life Oct 2019

Development Of An Autonomous Aerial Toolset For Agricultural Applications, Terrance Life

Honors College Capstone Experience/Thesis Projects

According to the United Nations, the world population is expected to grow from its current 7 billion to 9.7 billion by the year 2050. During this time, global food demand is also expected to increase by between 59% and 98% due to the population increase, accompanied by an increasing demand for protein due to a rising standard of living throughout developing countries. [1] Meeting this increase in required food production using present agricultural practices would necessitate a similar increase in farmland; a resource which does not exist in abundance. Therefore, in order to meet growing food demands, new methods ...


Coverage Properties Of Weibull Prediction Interval Procedures To Contain A Future Number Of Failures, Fanqi Meng, William Q. Meeker Sep 2019

Coverage Properties Of Weibull Prediction Interval Procedures To Contain A Future Number Of Failures, Fanqi Meng, William Q. Meeker

Statistics Publications

Prediction intervals are needed to quantify prediction uncertainty in, for example, warranty prediction and prediction of other kinds of field failures. Naïve prediction intervals (also known as intervals from the “plug-in method”) ignore the uncertainty in parameter estimates. Simulation-based calibration methods can be used to improve the accuracy of prediction interval coverage probabilities. This article investigates the finite-sample coverage probabilities for naive and calibrated prediction interval procedures for the number of future failures, based on the failure-time information obtained before a censoring time. We have designed and conducted a simulation experiment over combinations of factors with levels covering the ranges ...


A Tale Of Two Bays: The Development And Applications Of The Saco And Casco Modeling Project, Stephen M. Moore Aug 2019

A Tale Of Two Bays: The Development And Applications Of The Saco And Casco Modeling Project, Stephen M. Moore

Electronic Theses and Dissertations

This thesis details the development and application of a finite-volume, hydrodynamic model of Saco and Casco Bays. The primary study conducted herein focused on coupling storm simulations with sea level rise (SLR) to identify vulnerabilities of the two bays. The February 1978 Northeaster and an April freshwater discharge event in 2007 following the Patriot’s Day Storm were modeled by utilizing the Finite-Volume Coastal Ocean Model (FVCOM). Both events were repeatedly simulated under SLR scenarios ranging from 0 to 7 ft. Modeled storm responses were identified from the 1978 blizzard simulations and were tracked across SLR scenarios. By comparing changes ...


Estimating Error And Bias Of Offline Recommender System Evaluation Results, Mucun Tian Aug 2019

Estimating Error And Bias Of Offline Recommender System Evaluation Results, Mucun Tian

Boise State University Theses and Dissertations

Recommender systems are software applications deployed on the Internet to help people find useful items (e.g. movies, books, music, products) by providing recommendation lists. Before deploying recommender systems online, researchers and practitioners generally conduct offline evaluations to compare the accuracy of top- recommendation lists among candidate algorithms using users’ history consumption data. These offline evaluations typically use metrics and methodologies borrowed from machine learning and information retrieval and have several well-known biases that affect the validity of their results, including popularity bias and other biases arising from the missing-not-at-random nature of the data used. The existence of these biases ...


Ducci’S Four-Number Game: Making Sense Of A Classic Problem Using Mobile Simulation, Lingguo Bu Jul 2019

Ducci’S Four-Number Game: Making Sense Of A Classic Problem Using Mobile Simulation, Lingguo Bu

Journal of Humanistic Mathematics

Ducci’s Four-Number Game is a classic mathematical puzzle appealing to a wide audience for its procedural simplicity, mathematical richness, and aesthetic values. This article first describes a few activities appropriate for school students and mathematics teachers to make sense of the intriguing behavior of the game. Then, using a mobile simulation, we delve into the lengths of the Four-Number Game and the corresponding probability distribution. The Ducci number game is playful, engaging, and full of mathematical surprises.


Simulating Epidemics And Interventions On High Resolution Social Networks, Christopher E. Siu Jun 2019

Simulating Epidemics And Interventions On High Resolution Social Networks, Christopher E. Siu

Master's Theses and Project Reports

Mathematical models of disease spreading are a key factor of ensuring that we are prepared to deal with the next epidemic. They allow us to predict how an infection will spread throughout a population, thereby allowing us to make intelligent choices when attempting to contain the disease. Whether due to a lack of empirical data, a lack of computational power, a lack of biological understanding, or some combination thereof, traditional models must make sweeping assumptions about the behavior of a population during an epidemic.

In this thesis, we implement granular epidemic simulations using a rich social network constructed from real-world ...


Combining Geographic Information Systems And Agent-Based Models In Archaeology: Part 2 Of 3, Benjamin Davies, Iza Romanowska, Kathryn Harris, Stefani A. Crabtree May 2019

Combining Geographic Information Systems And Agent-Based Models In Archaeology: Part 2 Of 3, Benjamin Davies, Iza Romanowska, Kathryn Harris, Stefani A. Crabtree

Environment and Society Faculty Publications

Archaeologists are using spatial data in increasingly sophisticated analyses and invoking more explicit considerations of space in their interpretations. Geographic information systems (GIS) have become standard technology for professional archaeologists in the collection and management of spatial data. Many calls have been made to develop and adapt digital geospatial technologies for interpretation and understanding past social dynamics, but this has been limited to some extent by the static nature of map-oriented GIS approaches. Here, we illustrate how coupling GIS with agent-based modeling (ABM) can assist with more dynamic explorations of past uses of space and geospatial phenomena.


Smart Home Simulation In The Virtual World, Thomas Jones-Moore, David Son May 2019

Smart Home Simulation In The Virtual World, Thomas Jones-Moore, David Son

Scholars Week

The goal of this project is to produce a 'smart home' by using IoT and RFID like things in the virtual world to help solve problems. Some of these problems can be CPR training, etc. Used as an evaluation platform of suggested hardware to get a desired (or best fit) set of smart objects, or combinations with computer vision. Cost model to determine best fit based on: accuracy, lowest cost, easiest deployment, etc.


Paper Structure Formation Simulation, Tyler R. Seekins May 2019

Paper Structure Formation Simulation, Tyler R. Seekins

Electronic Theses and Dissertations

On the surface, paper appears simple, but closer inspection yields a rich collection of chaotic dynamics and random variables. Predictive simulation of paper product properties is desirable for screening candidate experiments and optimizing recipes but existing models are inadequate for practical use. We present a novel structure simulation and generation system designed to narrow the gap between mathematical model and practical prediction. Realistic inputs to the system are preserved as randomly distributed variables. Rapid fiber placement (~1 second/fiber) is achieved with probabilistic approximation of chaotic fluid dynamics and minimization of potential energy to determine flexible fiber conformations. Resulting digital ...


Autonomous Watercraft Simulation And Programming, Nicholas J. Savino May 2019

Autonomous Watercraft Simulation And Programming, Nicholas J. Savino

Undergraduate Theses and Capstone Projects

Automation of various modes of transportation is thought to make travel more safe and efficient. Over the past several decades advances to semi-autonomous and autonomous vehicles have led to advanced autopilot systems on planes and boats and an increasing popularity of self-driving cars. We simulated the motion of an autonomous vehicle using computational models. The simulation models the motion of a small-scale watercraft, which can then be built and programmed using an Arduino Microcontroller. We examined different control methods for a simulated rescue craft to reach a target. We also examined the effects of different factors, such as various biases ...


Spatio-Temporal Cluster Detection And Local Moran Statistics Of Point Processes, Jennifer L. Matthews Apr 2019

Spatio-Temporal Cluster Detection And Local Moran Statistics Of Point Processes, Jennifer L. Matthews

Mathematics & Statistics Theses & Dissertations

Moran's index is a statistic that measures spatial dependence, quantifying the degree of dispersion or clustering of point processes and events in some location/area. Recognizing that a single Moran's index may not give a sufficient summary of the spatial autocorrelation measure, a local indicator of spatial association (LISA) has gained popularity. Accordingly, we propose extending LISAs to time after partitioning the area and computing a Moran-type statistic for each subarea. Patterns between the local neighbors are unveiled that would not otherwise be apparent. We consider the measures of Moran statistics while incorporating a time factor under simulated ...


High-Performance Reductive Strategies For Big Data From Lc-Ms/Ms Proteomics, Muaaz Gul Awan Apr 2019

High-Performance Reductive Strategies For Big Data From Lc-Ms/Ms Proteomics, Muaaz Gul Awan

Dissertations

Mass Spectrometry (MS)-based proteomics utilizes high performance liquid chromatography in tandem with high-throughput mass spectrometers. These experiments can produce MS data sets with astonishing speed and volume that can easily reach peta-scale level, creating storage and computational problems for large-scale systems biology studies. Each spectrum output by a mass spectrometer may consist of thousands of peaks, which must all be processed to deduce the corresponding peptide. However, only a small percentage of peaks in a spectrum are useful for further processing, as most of the peaks are either noise or are not useful. Our experiments have shown that 90 ...


Jmasm 51: Bayesian Reliability Analysis Of Binomial Model – Application To Success/Failure Data, M. Tanwir Akhtar, Athar Ali Khan Mar 2019

Jmasm 51: Bayesian Reliability Analysis Of Binomial Model – Application To Success/Failure Data, M. Tanwir Akhtar, Athar Ali Khan

Journal of Modern Applied Statistical Methods

Reliability data are generated in the form of success/failure. An attempt was made to model such type of data using binomial distribution in the Bayesian paradigm. For fitting the Bayesian model both analytic and simulation techniques are used. Laplace approximation was implemented for approximating posterior densities of the model parameters. Parallel simulation tools were implemented with an extensive use of R and JAGS. R and JAGS code are developed and provided. Real data sets are used for the purpose of illustration.


Initial Stage Of Fluid-Structure Interaction Of A Celestial Icosahedron Shaped Vacuum Lighter Than Air Vehicle, Dustin P. Graves Mar 2019

Initial Stage Of Fluid-Structure Interaction Of A Celestial Icosahedron Shaped Vacuum Lighter Than Air Vehicle, Dustin P. Graves

Theses and Dissertations

The analysis of a celestial icosahedron geometry is considered as a potential design for a Vacuum Lighter than Air Vehicle (VLTAV). The goal of the analysis is ultimately to understand the initial fluid-structure interaction of the VLTAV and the surrounding airflow. Up to this point, previous research analyzed the celestial icosahedron VLTAV in relation to withstanding a symmetric sea-level pressure applied to the membrane of the structure. This scenario simulates an internal vacuum being applied in the worst-case atmospheric environmental condition. The next step in analysis is to determine the aerodynamic effects of the geometry. The experimental setup for obtaining ...


Time Varying Parameter Estimation Scheme For A Linear Stochastic Differential Equation, Olusegun Michael Otunuga Feb 2019

Time Varying Parameter Estimation Scheme For A Linear Stochastic Differential Equation, Olusegun Michael Otunuga

Olusegun Michael Otunuga

In this work, an attempt is made to estimate time varying parameters in a linear stochastic differential equation. By defining mk as the local admissible sample/data observation size at time tk, parameters and state at time tk are estimated using past data on interval [tkmk+1, tk]. We show that the parameter estimates at each time tk converge in probability to the true value of the parameters being estimated. A numerical simulation is presented by applying the local lagged adapted generalized method of moments (LLGMM) method to the stochastic differential models governing prices of energy commodities and stock ...


Exploring The Variance Of The Sample Variance Through Estimation And Simulation, Christina Stradwick Jan 2019

Exploring The Variance Of The Sample Variance Through Estimation And Simulation, Christina Stradwick

Theses, Dissertations and Capstones

In this thesis, we examine properties of the variance of the sample variance, which we will denote V (S 2 ). We derive a formula for this variance and show that it only depends on the sample size, variance, and kurtosis of the underlying distribution. We also derive the maximum likelihood estimators for this parameter, Vˆ (S 2 ), under the normal, exponential, Bernoulli, and Poisson distributions and end the thesis with simulations demonstrating the distributions of these estimators.


Virtual Reality And Analysis Framework For Studying Different Layout Designs, Madison Glines Jan 2019

Virtual Reality And Analysis Framework For Studying Different Layout Designs, Madison Glines

Browse all Theses and Dissertations

This thesis describes the tools for studying different design prototypes. The goal was to develop effective tools to study these designs using a data-driven approach. “Proof of concept” experiments were conducted, in which participants were allowed to interact with a virtual environment depicting different designs as data pertaining to their virtual location and orientation was recorded for later analysis. The designs included “flat” store racks, as opposed to racks with more varied shapes, as well as “curved” racks. Focus of the design studies was to assist in identifying optimal locations for different product types. The automated data collection mechanisms required ...


A Coupled Modeling Framework For Allocation Design In Land-Use And Land-Cover Changes To Optimize Biofuel Feedstock Production, Ana C. Cram Jan 2019

A Coupled Modeling Framework For Allocation Design In Land-Use And Land-Cover Changes To Optimize Biofuel Feedstock Production, Ana C. Cram

Open Access Theses & Dissertations

Environmental awareness has increased the demand for renewable energy. Notably, the production of biofuels from feedstock is gaining interest as a viable measure to reduce fossil fuels consumption. Nevertheless, it is crucial to identify the trade-offs between bioenergy crop cultivation and the environmental impact on land, water, and atmosphere.

Intensifying biofuel cultivation trigger effects associated with Land Use and Land-use-change, which are complex to assess. While hydrological models had been used to investigate the environmental impacts of land-use changes on water and soil quality, their quantitative assessment is often incomplete. Changes in land use and agricultural activities also contribute to ...


Personal Universes: A Solution To The Multi-Agent Value Alignment Problem, Roman V. Yampolskiy Jan 2019

Personal Universes: A Solution To The Multi-Agent Value Alignment Problem, Roman V. Yampolskiy

Faculty Scholarship

AI Safety researchers attempting to align values of highly capable intelligent systems with those of humanity face a number of challenges including personal value extraction, multi-agent value merger and finally in-silico encoding. State-of-the-art research in value alignment shows difficulties in every stage in this process, but merger of incompatible preferences is a particularly difficult challenge to overcome. In this paper we assume that the value extraction problem will be solved and propose a possible way to implement an AI solution which optimally aligns with individual preferences of each user. We conclude by analyzing benefits and limitations of the proposed approach.