Physical Sciences and Mathematics Commons^™

Jmasm 57: Bayesian Survival Analysis Of Lomax Family Models With Stan (R), Mohammed H. A. Abujarad, Athar Ali Khan

Journal of Modern Applied Statistical Methods

An attempt is made to fit three distributions, the Lomax, exponential Lomax, and Weibull Lomax to implement Bayesian methods to analyze Myeloma patients using Stan. This model is applied to a real survival censored data so that all the concepts and computations will be around the same data. A code was developed and improved to implement censored mechanism throughout using rstan. Furthermore, parallel simulation tools are also implemented with an extensive use of rstan.

Modeling Covid-19 Spread Using An Agent-Based Network, Stephen Yh Hung

Master's Theses

Beginning in 2019 and quickly spreading internationally, the Coronavirus disease Covid-19 became the first pandemic that many people have witnessed firsthand along with the severe disruption to their daily lives. A key field of research for Covid-19 that is studied by epidemiologists, biologists, and computer scientists alike is modeling the spread of Covid-19 in order to better predict future outbreaks of the pandemic and evaluate potential strategies to reduce infections, hospitalizations, and deaths.

This thesis proposes a method of modeling Covid-19 spread and interventions for local environments based on different levels of perspective. The goal for this thesis is to …

Physically Based Rendering Techniques To Visualize Thin-Film Smoothed Particle Hydrodynamics Fluid Simulations, Aditya H. Prasad

Dartmouth College Undergraduate Theses

This thesis introduces a methodology and workflow I developed to visualize smoothed hydrodynamic particle based simulations for the research paper ’Thin-Film Smoothed Particle Hydrodynamics Fluid’ (2021), that I co-authored. I introduce a physically based rendering model which allows point cloud simulation data representing thin film fluids and bubbles to be rendered in a photorealistic manner. This includes simulating the optic phenomenon of thin-film interference and rendering the resulting iridescent patterns. The key to the model lies in the implementation of a physically based surface shader that accounts for the interference of infinitely many internally reflected rays in its bidirectional surface …

Simulation Of Alfalfa Production With Epic, L. Chun, X. Xin, H. Tang

IGC Proceedings (1993-2023)

No abstract provided.

Statistical And Variational Modeling And Analysis Of Passive Integrated Photonic Devices, Norbert Dinyi Agbodo

Legacy Theses & Dissertations (2009 - 2024)

The success of Si as a platform for photonic devices and the associated availabilityof wafer-scale, ultra-high resolution lithography for Si CMOS has helped lead to the rapid advance of Si-based integrated photonics manufacturing over the past decade. This evolution is nearing the point of integration of Si-based photonics together with Si-CMOS for compact, high speed, high bandwidth, and cost-effective devices. However, due to the sensitive nature of passive and active photonic devices, variations inherent in wafer-based fabrication processes can lead to unacceptable levels of performance variation both within a give die and across a given wafer. Fully understanding the role …

Observational Studies In Group Testing And Potential Applications., Alexander Christopher Noll

Electronic Theses and Dissertations

The use of group testing to identify individuals with targeted outcomes in a population can greatly improve the efficiency, speed, and cost effectiveness of testing a population for an outcome, or at least for identifying the prevalence of an outcome in a population. The implementation of causal inference techniques can provide the basis for an observational study that would allow an investigator to gather estimates for treatment effectiveness if group testing was conducted on the population in a certain way. This thesis examines a simulation of the above outlined principles in order to demonstrate a potential application for determining treatment …

A Simulation Framework For Traffic Safety With Connected Vehicles And V2x Technologies, Md Abu Sayed

Theses and Dissertations

With the advancement in automobile technologies, existing research shows that connected vehicle (CV) technologies can provide better traffic safety through Surrogate Safety Measure (SSM). CV technologies involves two network systems: traffic network and wireless communication network. We found that the research in the wireless communication network for CV did not interact properly with the research in SSM in transportation network, and vice versa. Though various SSM has been proposed in previous studies, a few of them have been tested in simulation software in limited extent. On the other hand, A large body of researchers proposed various communication architecture for CV …

Incorporating Demographic Structure And Variable Interaction Types Into Community Assembly Models, Akhil Reddy Alasandagutti, Nayan Chawla

Honors Theses

Theoretical studies of ecological food webs have allowed ecologists to remove the constraints of specific location and timescales from their study of ecological communities; food webs are generally complex and thus empirical study is difficult. Further, this theoretical approach allows ecologists to compare ecological processes and outcomes across any possible food web structures. However, these simulated communities are only as useful as the model from which they were constructed. Modifying existing considerations in these models, and generating new ones, are the jobs of theoretical ecologists that seek to achieve the shared goal of a majority of simulations: representation of real …

The Effects Of Differences In Vaccination Rates Across Socioeconomic Groups On The Size Of Measles Outbreaks, Elizabeth Hunter, John D. Kelleher

Conference papers

Vaccination rates are often presented at the level of a country or region. However, within those areas there might be geographic or demographic pockets that have higher or lower vaccination rates. We use an agent-based model designed to simulate the spread of measles in Irish towns to examine if the effectiveness of vaccination rates to reduce disease at a population level is sensitive to the uniformity of vaccinations across socioeconomic groups. We find that when vaccinations are not applied evenly across socioeconomic groups we see more outbreaks and outbreaks with larger magnitudes.

Snore: An Intuitive Algorithm For Accurately Simulating N-Body Orbits, Connor L. Nance

Honors College Theses

We present SnOrE (Simple n-body Orbital Engine), a Python package which aims to simulate n-body orbital systems while simultaneously overcoming early educational barriers of computational astrodynamics for undergraduate physics students. SnOrE exploits rudimentary syntax and commonly-understood Python libraries to accurately simulate orbits of systems, given initial position and momentum conditions of each body in the system. As the n-body problem is as of yet unsolvable theoretically for n ≥ 3, having a numerical perspective on complicated orbits is of great importance to potentially understanding the processes of star and planet formation. Especially significant examples of this research …

Simulated Contact Tracing Of Covid-19 Propagation At Kutztown University For Fall 2020, Dale E. Parson

Computer Science and Information Technology Faculty

From mid-May through August 2020 the author designed, built, revised, and analyzed resulting data from two simulation programs for virtual contact tracing of COVID-19 infection propagation at Kutztown University in the fall 2020 semester. The first was command-line driven and non-graphical, with results distributed to faculty and administrators on May 28. The second was a three-dimensional interactive graphical simulation, distributed to faculty, administrators, and the public as a narrated video via YouTube on July 16. The algorithm is an adaptation of spreading activation as used in theoretical psychology and artificial intelligence research since the 1970s. It propagates discrete, probable infections …

Optomechanical Quantum Entanglement, Kahlil Y. Dixon

LSU Doctoral Dissertations

As classical technology approaches its limits, exploration of quantum technologies is critical. Quantum optics will be the basis of various cutting-edge research and applications in quantum technology. In particular, quantum optics quite efficacious when applied to quantum networks and the quantum internet. Quantum Optomechanics, a subfield of quantum optics, contains some novel methods for entanglement generation. These entanglement production methods exploit the noise re-encoding process, which is most often associated with creating unwanted phase noise in optical circuits. Using the adapted two-photon formalism and experimental results, we simulate (in an experimentally viable parameter space) optomechanical entanglement generation experiments. These simulations …

Application Of Physically Based Semi-Distributed Hec-Hms Model For Flow Simulation In Tributary Catchments Of Kaohsiung Area Taiwan, Fiaz Hussain, Ray-Shyan Wu, Kai-Chun Yu

Journal of Marine Science and Technology

Hydrologic modeling is a commonly used tool to understand the rainfallerunoff processes of gauged and ungauged catchments for proper quantitative estimation of water resources availability. In the present study, an attempt is made to simulate surface runoff using a physically based semi-distributed hydrological (HEC-HMS) model for four local-scale tributary catchments of Kaohsiung area Taiwan. The input physical parameters of the model were calculated and preprocessed in HEC-GeoHMS based on digital elevation model (DEM), land use, soil and hydro-meteorological data. The model performance was satisfactory with Nash Sutcliffe Efficiency (NSE) ¼ 0.51 to 0.86 and the coefficient of determination (R2) ¼ …

Using A Hybrid Agent-Based And Equation Based Model To Test School Closure Policies During A Measles Outbreak, Elizabeth Hunter, John D. Kelleher

Articles

Background

In order to be prepared for an infectious disease outbreak it is important to know what interventions will or will not have an impact on reducing the outbreak. While some interventions might have a greater effect in mitigating an outbreak, others might only have a minor effect but all interventions will have a cost in implementation. Estimating the effectiveness of an intervention can be done using computational modelling. In particular, comparing the results of model runs with an intervention in place to control runs where no interventions were used can help to determine what interventions will have the greatest …

The Wargaming Commodity Course Of Action Automated Analysis Method, William T. Deberry

Theses and Dissertations

This research presents the Wargaming Commodity Course of Action Automated Analysis Method (WCCAAM), a novel approach to assist wargame commanders in developing and analyzing courses of action (COAs) through semi-automation of the Military Decision Making Process (MDMP). MDMP is a seven-step iterative method that commanders and mission partners follow to build an operational course of action to achieve strategic objectives. MDMP requires time, resources, and coordination – all competing items the commander weighs to make the optimal decision. WCCAAM receives the MDMP's Mission Analysis phase as input, converts the wargame into a directed graph, processes a multi-commodity flow algorithm on …

Physics Engine On The Gpu With Opengl Compute Shaders, Quan Huy Minh Bui

Master's Theses

Any kind of graphics simulation can be thought of like a fancy flipbook. This notion is, of course, nothing new. For instance, in a game, the central computing unit (CPU) needs to process frame by frame, figuring out what is happening, and then finally issues draw calls to the graphics processing unit (GPU) to render the frame and display it onto the monitor. Traditionally, the CPU has to process a lot of things: from the creation of the window environment for the processed frames to be displayed, handling game logic, processing artificial intelligence (AI) for non-player characters (NPC), to the …

Ar-Based Simulation Interaction And Human Factor Assessment For Human Robot Cooperation Assembly Planning, Wang Qiang, Xiumin Fan, Qichang He, Wenmin Zhu

Journal of System Simulation

Abstract: To improve assembly efficiency, it has become a trend for traditional manual assembly workstations to be carried out human-robot collaboration transformation. To realize the safe and fast evaluation of the improvement scheme, a general human-robot collaboration simulation method and human factor evaluation method based on Augmented Reality are proposed. Four levels of human-robot collaboration assembly simulation are established. An interactive scheme between real human and virtual robot for visual detection, perception and feedback is established. A fuzzy comprehensive evaluation model of human physiological and psychological indicators for workstation design is constructed. The prototype system is developed. Taking the assembly …

A Quantized State System Method With Adaptive Quantum, Zhihua Li, Dongjin Fu, Li Guang, Zhihua Fan

Journal of System Simulation

Abstract: Quantized state system (QSS) is a new numerical integration method. It has advantages over the traditional time-discrete integration methods in solving general ordinary differential equation (ODE) systems. But it is hard to choose an appropriate quantum for the QSS method. In order to improve the accuracy and efficiency of QSS, a quantized state system method with adaptive quantum (VQSS) is proposed. Combined with the idea of step control in the variable step Runge-Kutta method, it can adaptively change the quantum in the process of computation. The feasibility of this algorithm is verified by the simulation of two examples …

Architecture Design Of An Emergency Command Simulation Exercise Platform Based On Tena, Peng Zhang, Qinfu Li

Journal of System Simulation

Abstract: Based on the analysis of the current situation and development needs of the emergency command simulation exercise platform and the common characteristics of most emergency command case scenarios, an emergency command simulation exercise platform architecture based on TENA (Test and Training Enabling Architecture) is designed and put forward, which can expand various simulation models such as disaster accidents, disaster-bearing subjects, higher-lower linkage command organizations, rescue forces, natural environment, etc. in a multi-granularity and modular manner, and interface with various exercise support and analysis evaluation tools, as well as heterogeneous systems such as external three-dimensional simulation, virtual reality/augmented reality equipment …

A Quantization-Based Integration Method For Stiff Ordinary Differential Equations, Zhihua Li, Jiang De, Chenjia Wu, Zhihua Fan

Journal of System Simulation

Abstract: QSS(Quantized State System) has advantages over the traditional time-discrete integration methods in solving general ordinary differential equation (ODE) systems, but it is not suitable for solving the stiff ODE systems. To effectively solve the stiff ODE systems, a step-correction optimization algorithm based on QSS (SCOA based-on QSS) is proposed, which combines the ideas of the QSS method and the implicit trapezoidal integral method. The simulation results of three typical stiff ODE cases show that the SCOA based-on QSS algorithm has advantages over other algorithms, and the simulation accuracy can be significantly improved by appropriately reducing the quantum size.

Collision Simulation Analysis Of Sam Movable Guardrail, Hongjun Cui, Sixue Li, Minqing Zhu, Li Xia

Journal of System Simulation

Abstract: Aiming at the problem of low anti-collision grade of the movable guardrail at the opening of the central divding belt of the expressway, a SAm-level concrete movable guardrail and a new connecting device are proposed. Based on the finite element method, the collision model between the vehicle and the guardrail is established, and the collision process is also calculated by LS-DYNA. According to the collision results of different vehicle types, the safety performance of the guardrail is evaluated in terms of cushioning, blocking and guiding performance. The OIV value is less than 12 m/s for small vehicles' collision with …

Integrating Dual‐Purpose Wheat Crops Into Different Sheep Production Systems In Southern Australia: Impacts On Livestock, Economic Returns And Risk, Andrew D. Moore, H. Dove, W. M. Kelman

IGC Proceedings (1993-2023)

No abstract provided.

Study On Validation Of Simulation Models Based On Weight Matrix Gray Relational Analysis, Xiaolei Ning, Yingxia Wu, Zhanqi Chen

Journal of System Simulation

Abstract: When used to validation of simulation models, ordinary gray relational analysis (GRA) usually stresses the similarity but ignores the nearness between the simulation test time series and flight test time series, while the nearness is part of model error. To reduce the risk in application of GRA to validation of simulation models, a new matrix gray relational analysis was proposed, which was in view of the similarity and the nearness between the simulation test time series and flight test time series, so it had a higher accuracy and reliability. The new model could solve the relational analysis problem with …

Research On Safety Protection Compositive Simulation Test Bed For Electric Secondary System, Zheniu Zhou, Angang Zheng, Heping Zou

Journal of System Simulation

Abstract: Existing information and network security simulation methodologies of model construction were analyzed and compared with each other, and applicability and limitations of each of them were summarized. Then according to safety protection needs to electric secondary system, based on previous research results of security simulation aiming at individual and partial objects, a safety protection compositive simulation test bed was designed and implemented in which eight kinds of simulation technology and solutions were integrated. This test bed included four simulation layers and seventeen categories of simulation test, and achieved a large scale, distributed, linkage-type simulation for comprehensive information security. This …

Modeling And Simulation Of Traction System In Hybrid Shunting Locomotive, Kun Shen, Wang Ling, Wang Jian, Xiaoyang Yao

Journal of System Simulation

Abstract: The structure of traction system in hybrid shunting locomotive was analyzed, and the working principles of traction system under multiform power models were introduced. Based on which, the models of traction system and power accumulators of this hybrid shunting locomotive were built by MATLAB/Simulink, then the simulation experiments on hybrid shunting locomotive with the power models of hybrid power, and pure diesel generator power or pure accumulator power were done respectively. The simulation results show that hybrid shunting locomotive can achieve reliable operation in diflFerent conditions by the designed main circuit structure, parameters and system energy management strategy.

Redesign Of The Jefferson Lab -300 Kv Dc Photo-Gun For High Bunch Charge Operations, S.A.K. Wijethunga, J. Benesch, Jean R. Delayen, C. Hernandez-Garcia, Geoffrey A. Krafft, Gabriel Palacios-Serrano, M.A. Mamun, M. Poelker, R. Suleiman

Physics Faculty Publications

Production of high bunch charge beams for the ElectronIon Collider (EIC) is a challenging task. High bunch charge (a few nC) electron beam studies at Jefferson Lab using an inverted insulator DC high voltage photo-gun showed evidence of space charge limitations starting at 0.3 nC, limiting the maximum delivered bunch charge to 0.7 nC for beam at -225 kV, 75 ps (FWHM) pulse width, and 1.64 mm (rms) laser spot size. The low extracted charge is due to the modest longitudinal electric field (Ez) at the photocathode leading to beam loss at the anode and downstream beam pipe. To reach …

Investigating The Effect Of Self-Trapped Holes In The Current Gain Mechanism Of $ \Beta \Mathbf{-}{\Mathbf{Ga}}_{\Mathbf{2}}{\Mathbf{O}}_{\Mathbf{3}}$ Schottky Diode Photodetectors, Fati̇h Akyol

Turkish Journal of Physics

Monoclinic gallium oxide $(\beta\mathrm{-}{\mathrm{Ga}}_{\mathrm{2}}{\mathrm{O}}_{\mathrm{3}})$ has found great research interest in solar blind photodetector (SBP) applications due to its' bandgap $\mathrm{\sim}$4.85 eV and availability of high quality native crystal growth. Applications including missile guidance, flame detection, underwater/intersatellite communication and water purification systems require SBPs. $\beta\mathrm{-}{\mathrm{Ga}}_{\mathrm{2}}{\mathrm{O}}_{\mathrm{3}}$ SBPs with high responsivity values have been published indicating internal gain in these devices. The gain has been attributed to accumulation of self-trapped hole (STH) below Schottky metal which the lowers Schottky barrier in these devices based on some approximations rather than a proper device simulation. In this paper, technology computer-aided design (TCAD) simulation of $\beta\mathrm{-}{\mathrm{Ga}}_{\mathrm{2}}{\mathrm{O}}_{\mathrm{3}}$ …

Equations Of State For Warm Dense Carbon From Quantum Espresso, Derek J. Schauss

Theses and Dissertations

Warm dense plasma is the matter that exists, roughly, in the range of 10,000 to 10,000,000 Kelvin and has solid-like densities, typically between 0.1 and 10 grams per centimeter. Warm dense fluids like hydrogen, helium, and carbon are believed to make up the interiors of many planets, white dwarfs, and other stars in our universe. The existence of warm dense matter (WDM) on Earth, however, is very rare, as it can only be created with high-energy sources like a nuclear explosion. In such an event, theoretical and computational models that accurately predict the response of certain materials are thus very …

Implementation Strategies For Modeling And Simulation In Military Organizations, Cody Lynn Taylor

Walden Dissertations and Doctoral Studies

Some IT project managers working for U.S. military organizations are struggling to implement modern modeling and simulation (M&S) technology. Implementation strategies are needed to help IT practitioners deliver meaningful simulations and models that ultimately help senior leaders make logical and science-based decisions. Grounded in the extended technology acceptance model, the purpose of this qualitative multiple-case study was to explore strategies some IT project managers supporting U.S. military organizations use to implement modern M&S technology. The participants included 10 civil servants who successfully implemented modeling and simulation technology for military organizations located in the United States eastern region. Data was collected …

The Simulation Extrapolation Method With Differential Measurement Error, Dominic Partipilo

Graduate Research Theses & Dissertations

Most of statistical theory operates under the assumption that the true values of covariates have been measured correctly, but it is not always possible to obtain the true values of these covariates. A common issue, specifically in regression models, is that predictors are misclassified or measured with systematic measurement error. There have been many methods developed for handling measurement error, specifically in the case where measurement error is nondifferential, where the measurement error can be treated as independent from the covariates. The frequentist method known as simulation extrapolation (SIMEX) is one of these methods that specifically handles the case for …