Physical Sciences and Mathematics Commons^™

Gravity Waves, Na Lidar, Yafang Guo, Alan Z. Liu

Publications

Vertical energy transports due to dissipating gravity waves in the mesopause region (85–100 km) are analyzed using over 400 h of observational data obtained from a narrow-band sodium wind-temperature lidar located at Andes Lidar Observatory (ALO), Cerro Pachón (30.25°S, 70.73°W), Chile. Sensible heat flux is directly estimated using measured temperature and vertical wind; energy flux is estimated from the vertical wavenumber and frequency spectra of temperature perturbations; and enthalpy flux is derived based on its relationship with sensible heat and energy fluxes. Sensible heat flux is mostly downward throughout the region. Enthalpy flux exhibits an annual oscillation with maximum downward …

Setting Constraints On The Lunar Exosphere: A Comprehensive Analysis Of Velocity Resolved Sodium And Potassium Line Profile Measurements, Dona Chathuni P. Kuruppuaratchi

Doctoral Dissertations and Master's Theses

This dissertation outlines and presents the most comprehensive set of velocity-resolved measurements of sodium D2 (5889.9509 Å) lines taken over multiple lunations spanning seven years (2011 – 2017). These data are used to study the morphology and dynamics of the lunar exosphere. Additionally, potassium D1 (7698.9646 Å) is used as a complement to sodium. The two species approach, with sodium being the main attraction, provides constraints on the critical drivers of the lunar exosphere. Observations were made at the National Solar Observatory McMath – Pierce Telescope, Kitt Peak, Arizona where I personally collected both sodium and potassium data over about …

Nearly 30,000 Late-Type Main-Sequence Stars With Stellar Age From Lamost Dr5, Jiajun Zhang, Terry D. Oswalt, Jingkun Zhao, Xilong Liang, Xianhao Ye, Gang Zhao

Publications

We construct a sample of nearly 30,000 main-sequence stars with 4500K < Teff < 5000K and stellar ages estimated by the chromospheric activity−age relation. This sample is used to determine the age distribution in the R − Z plane of the Galaxy, where R is the projected Galactocentric distance in the disk midplane and Z is the height above the disk midplane. As |Z| increases, the percentage of old stars becomes larger. It is known that scale-height of Galactic disk increases as R increases, which is called flare. A mild flare from R ∼ 8.0 to 9.0 kpc in stellar age distribution is found. We also find that the velocity dispersion increases with age as confirmed by previous studies. Finally we present spiral-shaped structures in Z − υZ phase space in three stellar age bins. The spiral is clearly seen in the age bin of [0, 1] Gyr, which suggests that a vertical perturbation to the disk probably took place within the last ∼ 1.0 Gyr.

The Dynamics Of Nonlinear Atmospheric Acoustic-Gravity Waves Generated By Tsunamis Over Realistic Bathymetry, P. A. Inchin, C. J. Heale, J. B. Snively, M. D. Zettergren

Publications

The investigation of atmospheric tsunamigenic acoustic and gravity wave (TAGW) dynamics, from the ocean surface to the thermosphere, is performed through the numerical computations of the 3D compressible nonlinear Navier-Stokes equations. Tsunami propagation is first simulated using a nonlinear shallow water model, which incorporates instantaneous or temporal evolutions of initial tsunami distributions (ITD). Ocean surface dynamics are then imposed as a boundary condition to excite TAGWs into the atmosphere from the ground level. We perform a case study of a large tsunami associated with the 2011 M9.1 Tohuku-Oki earthquake and parametric studies with simplified and demonstrative bathymetry and ITD. Our …

Kelvin-Helmholtz Billow Interactions And Instabilities In The Mesosphere Over The Andes Lidar Observatory: 1. Observations, J. H. Hecht, R. L. Walterscheid, A. Z. Liu, D. C. Fritts, L. J. Gelinas, R. J. Rudy

Publications

A very high spatial resolution (∼25 m pixel at 90 km altitude) OH airglow imager was installed at the Andes Lidar Observatory on Cerro Pachón, Chile, in February 2016. This instrument was collocated with a Na wind-temperature lidar. On 1 March 2016, the lidar data showed that the atmosphere was dynamically unstable before 0100 UT and thus conducive to the formation of Kelvin-Helmholtz instabilities (KHIs). The imager revealed the presence of a KHI and an apparent atmospheric gravity wave (AGW) propagating approximately perpendicular to the plane of primary KHI motions. The AGW appears to have induced modulations of the shear …

A Statistical Learning Regression Model Utilized To Determine Predictive Factors Of Social Distancing During Covid-19 Pandemic, Timothy A. Smith, Albert J. Boquet, Matthew V. Chin

Publications

In an application of the mathematical theory of statistics, predictive regression modelling can be used to determine if there is a trend to predict the response variable of social distancing in terms of multiple predictor input “predictor” variables. In this study the social distancing is measured as the percentage reduction in average mobility by GPS records, and the mathematical results obtained are interpreted to determine what factors drive that response. This study was done on county level data from the state of Florida during the COVID-19 pandemic, and it is found that the most deterministic predictors are county population density …

An Exploratory Study Of General Aviation Visual To Instrument Meteorological Condition Contextual Factors, James Harry Hartman Iii

Doctoral Dissertations and Master's Theses

The purpose of this dissertation was to bridge the existing literature gap of outdated contextual factor (CF) research through examination and determination of current General Aviation (GA) Title 14 Code of Federal Regulations (CFR) Part 91 visual flight rules (VFR)-into-instrument meteorological condition (IMC) contextual factors. Contextual factors are a multifaceted arrangement of pertinent events or occurrences contributing to pilot accidents in weather-related decision-making errors. A total of 46 contextual factors were identified and examined from the reviewed research literature. The study examined and determined the presence of the 46 contextual factors, frequencies, and manifestations in the GA VFR-into-IMC Aviation Accident …

A Forensic First Look At A Pos Device: Searching For Pci Dss Data Storage Violations, Stephen Larson, James Jones, Jim Swauger

Journal of Digital Forensics, Security and Law

According to the Verizon 2018 Data Breach Investigations Report, 321 POS terminals (user devices) were involved in about 14% of the 2,216 data breaches in 2017 (Verizon, 2018). These data breaches involved standalone POS terminals as well as associated controller systems. This paper examines a standalone Point-of-Sale (POS) system which is ubiquitous in smaller retail stores and restaurants. An attempt to extract unencrypted data and identify possible violations of the Payment Card Industry Data Security Standard (PCI DSS) requirement to protect stored cardholder data were be made. Persistent storage (flash memory chips) were removed from the devices and their contents …

Towards Increasing Trust In Expert Evidence Derived From Malware Forensic Tools, Ian M. Kennedy, Blaine Price, Arosha Bandara

Journal of Digital Forensics, Security and Law

Following a series of high profile miscarriages of justice in the UK linked to questionable expert evidence, the post of the Forensic Science Regulator was created in 2008. The main objective of this role is to improve the standard of practitioner competences and forensic procedures. One of the key strategies deployed to achieve this is the push to incorporate a greater level of scientific conduct in the various fields of forensic practice. Currently there is no statutory requirement for practitioners to become accredited to continue working with the Criminal Justice System of England and Wales. However, the Forensic Science Regulator …

Finite-Time State Estimation For An Inverted Pendulum Under Input-Multiplicative Uncertainty, Sergey V. Drakunov, William Mackunis, Anu Kossery Jayaprakash, Krishna Bhavithavya Kidambi, Mahmut Reyhanoglu

Publications

A sliding mode observer is presented, which is rigorously proven to achieve finite-time state estimation of a dual-parallel underactuated (i.e., single-input multi-output) cart inverted pendulum system in the presence of parametric uncertainty. A salient feature of the proposed sliding mode observer design is that a rigorous analysis is provided, which proves finite-time estimation of the complete system state in the presence of input-multiplicative parametric uncertainty. The performance of the proposed observer design is demonstrated through numerical case studies using both sliding mode control (SMC)- and linear quadratic regulator (LQR)-based closed-loop control systems. The main contribution presented here is the rigorous …

Finite-Time State Estimation For An Inverted Pendulum Under Input-Multiplicative Uncertainty, William Mackunis, Sergey V. Drakunov, Anu Kossery Jayaprakash, Krishna Bhavithavya Kidambi, Mahmut Reyhanoglu

Publications

A sliding mode observer is presented, which is rigorously proven to achieve finite-time state estimation of a dual-parallel underactuated (i.e., single-input multi-output) cart inverted pendulum system in the presence of parametric uncertainty. A salient feature of the proposed sliding mode observer design is that a rigorous analysis is provided, which proves finite-time estimation of the complete system state in the presence of input-multiplicative parametric uncertainty. The performance of the proposed observer design is demonstrated through numerical case studies using both sliding mode control (SMC)- and linear quadratic regulator (LQR)-based closed-loop control systems. The main contribution presented here is the rigorous …

Two Portions Of Sagittarius Stream In The Lamost Complete Spectroscopic Survey Of Pointing Area At Southern Galactic Cap, J. K. Zhao, Terry D. Oswalt, X. H. Ye, H. Wu, M. Yang, X. X. Xue, Y. Q. Chen, J. J. Zhan, G. Zhao

Publications

We constructed a sample of 13,798 stars with Teff , log g, [Fe/H], radial velocity, proper motions and parallaxes from LAMOST DR5 and Gaia DR2 in the LAMOST Complete Spectroscopic Survey of Pointing Area (LaCoSSPAr) at the Southern Galactic Cap consisting of areas A and B. Using the distributions in both proper motions and radial velocity, we detected very significant overdensi- ties in these two areas. These substructures most likely are portions of Sagittarius (Sgr) stream. With the Density-Based Spatial Clustering of Applications with Noise (DBSCAN) algorithm, 220 candidates stream members were identified. Based upon distance to the Sun and …

Large Scale Upper-Level Precursors For Dust Storm Formation Over North Africa And Poleward Transport To The Iberian Peninsula. Part I: An Observational Analysis, J.A. G. Orza, Michael L. Kaplan, S. Dhital, S. Fiedler

Publications

The analysis of three extreme African dust outbreaks over the Iberian Peninsula (IP) shows that a double Rossby wave breaking (RWB) process in the polar jet (PJ) creates the conditions for dust storm formation over subtropical deserts in North Africa and the restructuring of upper-level air flows critical for the dust transport poleward after ablation. Two consecutive anticyclonic RWBs initiate over the IP and the adjacent Atlantic, the first commencing 10 days before dust reaches the IP and the second three to five days later. The first RWB becomes quasi-stationary over the eastern Mediterranean when the second RWB develops. In …

Cryptography, Passwords, Privacy, And The Fifth Amendment, Gary C. Kessler, Ann M. Phillips

Journal of Digital Forensics, Security and Law

Military-grade cryptography has been widely available at no cost for personal and commercial use since the early 1990s. Since the introduction of Pretty Good Privacy (PGP), more and more people encrypt files and devices, and we are now at the point where our smartphones are encrypted by default. While this ostensibly provides users with a high degree of privacy, compelling a user to provide a password has been interpreted by some courts as a violation of our Fifth Amendment protections, becoming an often insurmountable hurdle to law enforcement lawfully executing a search warrant. This paper will explore some of the …

A Two-Stage Model For Social Network Investigations In Digital Forensics, Anne David, Sarah Morris, Gareth Appleby-Thomas

Journal of Digital Forensics, Security and Law

This paper proposes a two-stage model for identifying and contextualizing features from artefacts created as a result of social networking activity. This technique can be useful in digital investigations and is based on understanding and the deconstruction of the processes that take place prior to, during and after user activity; this includes corroborating artefacts. Digital Investigations are becoming more complex due to factors such as, the volume of data to be examined; different data formats; a wide range of sources for digital evidence; the volatility of data and the limitations of some of the standard digital forensic tools. This paper …

Experimental Study Of Breathers And Rogue Waves Generated By Random Waves Over Non-Uniform Bathymetry, A. Ludu, A. Wang, Z. Zong, L. Zou, Y. Pei

Publications

We present experimental evidence of formation and persistence of localized waves, breathers, and solitons, occurring in a random sea state and uniformly traveling over non-uniform bathymetry. Recent studies suggest connections between breather dynamics and irregular sea states and between extreme wave formation and breathers, random sea states, or non-uniform bathymetry individually. In this paper, we investigate the joint connection between these phenomena, and we found that breathers and deep-water solitons can persist in more complex environments. Three different sets of significant heights have been generated within a Joint North Sea Wave Observation Project wave spectrum, and the wave heights were …

Observations Of An Extreme Atmospheric River Storm With A Diverse Sensor Network, B. J. Hatchett, Michael L. Kaplan, Q. Cao, P. B. Dawson, C. J. Ellis, Et Al.

Publications

Observational networks enhance real‐time situational awareness for emergency and water resource management during extreme weather events. We present examples of how a diverse, multitiered observational network in California provided insights into hydrometeorological processes and impacts during a 3‐day atmospheric river storm centered on 14 February 2019. This network, which has been developed over the past two decades, aims to improve understanding and mitigation of effects from extreme storms influencing water resources and natural hazards. We combine atmospheric reanalysis output and additional observations to show how the network allows: (1) the validation of record cool season precipitable water observations over southern …

Dynamics Of Discontinuities In Elastic Solids, Arkadi Berezovski, Mihhail Berezovski

Publications

The paper is devoted to evolving discontinuities in elastic solids. A discontinuity is represented as a singular set of material points. Evolution of a discontinuity is driven by the configurational force acting at such a set. The main attention is paid to the determination of the velocity of a propagating discontinuity. Martensitic phase transition fronts and brittle cracks are considered as representative examples.

Use Of Lidar Data To Investigate The Influence Of Bottom Friction Coefficients For Storm Surge Modeling Of Hurricane Michael In The Florida Panhandle, Sky Comarsh White

Doctoral Dissertations and Master's Theses

Current storm surge modeling typically uses local land use land cover (LULC) maps coupled with lookup tables to parameterize surface roughness because the process is defensible and easily automated at the regional scale. However, this is not a truly accurate method since LULC data is generalized for an area and often contains misclassifications. Intra-class variability is also a concern as variations in obstacle density within LULC classifications are prominent at typical storm surge model resolution scales ranging from 20-meters to 200-meters in the floodplain. Using lidar data, topography and the 3-dimensional structure of above-ground obstructions can be more accurately characterized, …

An Aviation Weather Preflight Decision Support Tool To Improve Ga Pilots Preflight And Inflight Performance, Jayde M. King

Doctoral Dissertations and Master's Theses

Low hour, inexperienced General Aviation (GA) pilots account for the majority of weather-related incidents, which often result in fatalities. Previous research identifies poor preflight planning practices and a lack of aviation weather knowledge as key contributing factors to the high novice private pilot accident and fatality rate. Research invested into resolving these issues often attempt to introduce new inflight weather technology to assist pilots with weather avoidance. However, these interventions usually result in pilots using the information to strategically navigate closer to degraded weather conditions (Beringer & Ball, 2004; Burgess & Thomas, 2004). Therefore, the purpose of this study was …

Optimization Of Spacecraft Formations About Lagrange Points For The Next Generation Space Weather Prediction Mission, Roberto Cuéllar Rangel

Doctoral Dissertations and Master's Theses

This thesis’s work serves as proof of concept for the Next Generation Space Weather Prediction Mission, a multi-spacecraft mission at various libration points whose objective is to forecast Space Weather hazards with a 12day warning time. This thesis deals with the design and control of orbits of spacecraft formations at different libration points. The systems studied are SunEarth, SunVenus, SunMercury, and SunMars. The orbit design and formation keeping control of the spacecraft are solved simultaneously using an optimization software called DIDO. Initial conditions are obtained through two different strategies. The first one, by placing the spacecraft in a tetrahedral formation …

Python Implementation Of Batch Least-Squares Filter For Satellite Orbit Determination, Austin Ogle

Doctoral Dissertations and Master's Theses

Accurate orbit determination techniques are fundamental to the maintenance and execution of any ongoing space-based mission. This project serves as a guide and demonstration of a batch sequential least-squares filter for Earth-orbiting satellites using exclusively open-source technologies. The target audience for this project was an academic institution aiming to keep track of an irregularly documented satellite. The observation function mimics a telescope, accepting right ascension and declination as measured values.

State propagation was handled using the Poliastro library. This package boasts FORTRANlevel speed by utilizing the DOPRI8 integrator, explicitly calling FORTRAN code. Matrix inversion was solved using the SciPy banded …

What’S In The Cloud? - An Examination Of The Impact Of Cloud Storage Usage On The Browser Cache., Graeme Horsman

Journal of Digital Forensics, Security and Law

Cloud storage is now a well established and popular service adopted by many individuals, often at limited or no cost. It provides users with the ability to store content on a cloud service provider’s infrastructure offering the benefit of redundancy, reliability, security, flexibility of access and the potential assumed liability of the provider for data loss within the contexts of a licensing agreement. Consequently, this form of remote storage provides a regulatory challenge as content which once resided upon a seized digital exhibit, available for scrutiny during a digital forensic investigatory, may no longer be present where attempting to acquire …

An Evaluation Of Data Erasing Tools, Andrew Jones, Isaac Afrifa

Journal of Digital Forensics, Security and Law

The permanent removal of data from media is a major area of concern mainly because of the misconception that once a file is deleted or storage media is formatted, it cannot be recovered. There has been the development of both commercial and freeware data erasing tools, which all claim complete file or disk erasure. This report analyzes the efficiency of a number of these tools in performing erasures on an electromechanical drive. It focuses on a selection of popular and modern erasing tools; taking into consideration their usability, claimed erasing standards and whether they perform complete data erasure with the …

2n-Dimensional Canonical Systems And Applications, Andrei Ludu, Keshav Baj Acharya

Publications

We study the 2N-dimensional canonical systems and discuss some properties of its fundamental solution. We then discuss the Floquet theory of periodic canonical systems and observe the asymptotic behavior of its solution. Some important physical applications of the systems are also discussed: linear stability of periodic Hamiltonian systems, position-dependent effective mass, pseudo-periodic nonlinear water waves, and Dirac systems.

Semi-Lagrangian Implicit Bhatnagar-Gross-Krook Collision Model For The Finite-Volume Discrete Boltzmann Method, Leitao Chen, Sauro Succi, Xiaofeng Cai, Laura Schaefer

Publications

In order to increase the accuracy of temporal solutions, reduce the computational cost of time marching, and improve the stability associated with collisions for the finite-volume discrete Boltzmann method, an advanced implicit Bhatnagar-Gross-Krook (BGK) collision model using a semi-Lagrangian approach is proposed in this paper. Unlike existing models, in which the implicit BGK collision is resolved either by a temporal extrapolation or by a variable transformation, the proposed model removes the implicitness by tracing the particle distribution functions (PDFs) back in time along their characteristic paths during the collision process. An interpolation scheme is needed to evaluate the PDFs at …

From Degree To Chief Information Security Officer (Ciso): A Framework For Consideration, Wendi M. Kappers, Martha Nanette Harrell,

Publications

Educational entities are establishing program degree content designed to ensure cybersecurity and information security assurance skills are adequate and efficient for preparing students to be successful in this very important field. Many Master’s level programs include courses that address these skills in an attempt to provide a well-rounded program of study. However, undergraduates who are in the practitioner’s world have other alternatives to gain these skills. These individuals can gain various certifications, such as the Certified Information Systems Security Professional (CISSP) or the Certified Information Security Manager (CISM). Due to a perceived gap between academics and field knowledge, it appears …

Mesopause Airglow Disturbances Driven By Nonlinear Infrasonic Acoustic Waves Generated By Large Earthquakes, P. A. Inchin, J. B. Snively, J. Aguilar Guerrero, M. D. Zettergren, A. Williamson, D. Melgar

Publications

Near-epicentral mesopause airglow perturbations, driven by infrasonic acoustic waves (AWs) during a nighttime analog of the 2011 M9.1 Tohoku-Oki earthquake, are simulated through the direct numerical computation of the 3D nonlinear Navier-Stokes equations. Surface dynamics from a forward seismic wave propagation simulation, initialized with a kinematic slip model and performed with the SPECFEM3D_GLOBE model, are used to excite AWs into the atmosphere from ground level. Simulated mesopause airglow perturbations include steep oscillations and persistent nonlinear depletions up to 50% and 70% from the background state, respectively, for the hydroxyl OH(3,1) and oxygen O(1S) 557.7-nm emissions. Results suggest that …

Coherent Captain Mills: The Search For Sterile Neutrinos, Ashley Elliott, Jeramy Gordon, Jonah Greenwood, Rachel Lake, Ryder Moreno, Emily Strawn, Kate Walker

Discovery Day - Prescott

The observation of neutrino oscillations confirms that the active neutrinos (νe, νμ, ντ) are comprised of three mass eigenstates with Δm2 values between 10-3 to 10-5 eV2 . However, a persistent phenomenon has been observed at LSND, MiniBooNE and other shortbaseline experiments (SBE) where Δm2 ~ 1eV2 and is not compatible with the current mixing between mass eigenstates. However, a 4th neutrino, a sterile neutrino (νs) that doesn’t participate in weak interactions could explain the phenomena observed as SBE’s. An experiment has been constructed at TA-53 at Los Alamos National Laboratory to investigate this large Δm2 ~ 1eV2 and determine …

Discontinuity-Driven Mesh Alignment For Evolving Discontinuities In Elastic Solids, Mihhail Berezovski, Arkadi Berezovski

Publications

A special mesh adaptation technique and a precise discontinuity tracking are presented for an accurate, efficient, and robust adaptive-mesh computational procedure for one-dimensional hyperbolic systems of conservation laws, with particular reference to problems with evolving discontinuities in solids. The main advantage of the adaptive technique is its ability to preserve the modified mesh as close to the original fixed mesh as possible. The constructed method is applied to the martensitic phase-transition front propagation in solids.