# Physical Sciences and Mathematics Commons™

## All Articles in Physical Sciences and Mathematics

178,117 full-text articles. Page 5 of 4575.

A Bit Like Cash: Understanding Cash-For-Bitcoin Transactions Through Individual Vendors, 2018 University of Central Oklahoma

#### A Bit Like Cash: Understanding Cash-For-Bitcoin Transactions Through Individual Vendors, Stephanie J. Robberson, Mark R. Mccoy

##### Journal of Digital Forensics, Security and Law

As technology improves and economies become more globalized, the concept of currency has evolved. Bitcoin, a cryptographic digital currency, has been embraced as a secure and convenient type of money. Due to its security and privacy for the user, Bitcoin is a good tool for conducting criminal trades. The Financial Crimes Enforcement Network (FinCEN) has regulations in place to make identification information of Bitcoin purchasers accessible to law enforcement, but enforcing these rules with cash-for-Bitcoin traders is difficult. This study surveyed cash-for-Bitcoin vendors in Oklahoma, Texas, Arkansas, Missouri, Kansas, Colorado, and New Mexico to determine personal demographic information, knowledge of ...

Using Cyclical Components To Improve The Forecasts Of The Stock Market And Macroeconomic Variables, 2018 Curtin University Malaysia

#### Using Cyclical Components To Improve The Forecasts Of The Stock Market And Macroeconomic Variables, Kenneth R. Szulczyk, Shibley Sadique

##### Journal of Modern Applied Statistical Methods

Economic variables such as stock market indices, interest rates, and national output measures contain cyclical components. Forecasting methods excluding these cyclical components yield inaccurate out-of-sample forecasts. Accordingly, a three-stage procedure is developed to estimate a vector autoregression (VAR) with cyclical components. A Monte Carlo simulation shows the procedure estimates the parameters accurately. Subsequently, a VAR with cyclical components improves the root-mean-square error of out-of-sample forecasts by 50% for a stock market model with macroeconomic variables.

Using Coherent Phonons For Ultrafast Control Of The Dirac Node Of Srmnsb2, 2018 Santa Clara University

#### Using Coherent Phonons For Ultrafast Control Of The Dirac Node Of Srmnsb2, Christopher P. Weber, Madison G. Masten, Thomas C. Ogloza, Bryan S. Berggren, Michael K. L. Man, Keshav M. Dani, Jinyu Liu, Zhiqiang Mao, Dennis D. Klug, Adebayo A. Adeleke, Yansun Yao

##### Physics

SrMnSb2 is a candidate Dirac semimetal whose electrons near the Y point have the linear dispersion and low mass of a Dirac cone. Here we demonstrate that ultrafast, 800-nm optical pulses can launch coherent phonon oscillations in Sr0.94Mn0.92Sb2, particularly an Ag mode at 4.4 THz. Through first-principles calculations of the electronic and phononic structure of SrMnSb2, we show that high-amplitude oscillations of this mode would displace the atoms in a way that transiently opens and closes a gap at the node of the Dirac cone. The ability to control ...

Land-Use/Land-Cover Changes And Their Influence On The Ecosystem In Chengdu City, China During The Period Of 1992–2018, 2018 Chinese Academy of Sciences

#### Land-Use/Land-Cover Changes And Their Influence On The Ecosystem In Chengdu City, China During The Period Of 1992–2018, Xiaojuan Lin, Min Xu, Chunxiang Cao, Ramesh P. Singh, Wei Chen, Hongrun Ju

##### Mathematics, Physics, and Computer Science Faculty Articles and Research

Due to urban expansion, economic development, and rapid population growth, land use/land cover (LULC) is changing in major cities around the globe. Quantitative analysis of LULC change is important for studying the corresponding impact on the ecosystem service value (ESV) that helps in decision-making and ecosystem conservation. Based on LULC data retrieved from remote-sensing interpretation, we computed the changes of ESV associated with the LULC dynamics using the benefits transfer method and geographic information system (GIS) technologies during the period of 1992–2018 following self-modified coefficients which were corrected by net primary productivity (NPP). This improved approach aimed to ...

Positive And Z-Operators On Closed Convex Cones, 2018 University of Maryland Baltimore County

#### Positive And Z-Operators On Closed Convex Cones, Michael J. Orlitzky

##### Electronic Journal of Linear Algebra

Let $K$ be a closed convex cone with dual $\dual{K}$ in a finite-dimensional real Hilbert space. A \emph{positive operator} on $K$ is a linear operator $L$ such that $L\of{K} \subseteq K$. Positive operators generalize the nonnegative matrices and are essential to the Perron-Frobenius theory. It is said that $L$ is a \emph{\textbf{Z}-operator} on $K$ if % \begin{equation*} \ip{L\of{x}}{s} \le 0 \;\text{ for all } \pair{x}{s} \in \cartprod{K}{\dual{K}} \text{ such that } \ip{x}{s} = 0. \end{equation*} % The \textbf{Z}-operators are generalizations of \textbf{Z ...

Spectral Bounds For The Connectivity Of Regular Graphs With Given Order, 2018 Maastricht University

#### Spectral Bounds For The Connectivity Of Regular Graphs With Given Order, Aida Abiad, Boris Brimkov, Xavier Martinez-Rivera, Suil O, Jingmei Zhang

##### Electronic Journal of Linear Algebra

The second-largest eigenvalue and second-smallest Laplacian eigenvalue of a graph are measures of its connectivity. These eigenvalues can be used to analyze the robustness, resilience, and synchronizability of networks, and are related to connectivity attributes such as the vertex- and edge-connectivity, isoperimetric number, and characteristic path length. In this paper, two upper bounds are presented for the second-largest eigenvalues of regular graphs and multigraphs of a given order which guarantee a desired vertex- or edge-connectivity. The given bounds are in terms of the order and degree of the graphs, and hold with equality for infinite families of graphs. These results ...

Bounded Linear Operators That Preserve The Weak Supermajorization On $\Ell^1(I)^+$, 2018 Faculty of Mechanical Engineering, Department of Mathematics,University of Niš, Serbia

#### Bounded Linear Operators That Preserve The Weak Supermajorization On $\Ell^1(I)^+$, Martin Z. Ljubenović, Dragan S. Djordjevic

##### Electronic Journal of Linear Algebra

Linear preservers of weak supermajorization which is defined on positive functions contained in the discrete Lebesgue space $\ell^1(I)$ are characterized. Two different classes of operators that preserve the weak supermajorization are formed. It is shown that every linear preserver may be decomposed as sum of two operators from the above classes, and conversely, the sum of two operators which satisfy an additional condition is a linear preserver. Necessary and sufficient conditions under which a bounded linear operator is a linear preserver of the weak supermajorization are given. It is concluded that positive linear preservers of the weak supermajorization ...

Of Mice And Math: Four Models, Four Collaborations., 2018 Pomona College

#### Of Mice And Math: Four Models, Four Collaborations., Ami Radunskaya

##### Annual Symposium on Biomathematics and Ecology: Education and Research

No abstract provided.

Novel Cell-Based Model Of The Generation And Maintenance Of The Shape And Structure Of The Multi-Layered Shoot Apical Meristem Of Arabidopsis Thaliana, 2018 University of California, Riverside

#### Novel Cell-Based Model Of The Generation And Maintenance Of The Shape And Structure Of The Multi-Layered Shoot Apical Meristem Of Arabidopsis Thaliana, Mikahl Banwarth-Kuhn, Ali Nematbakhsh, Stephen Snipes, Kevin Rodriguez, Carolyn Rasmussen, G. Venugopala Reddy, Mark Alber

##### Annual Symposium on Biomathematics and Ecology: Education and Research

No abstract provided.

Theory On Thermodynamic Constraints To Biogeochemical And Metabolic Diversity, 2018 Arizona State University

#### Theory On Thermodynamic Constraints To Biogeochemical And Metabolic Diversity, Jordan Okie, Everett Shock

##### Annual Symposium on Biomathematics and Ecology: Education and Research

No abstract provided.

2018 Department of Mathematics, Illinois State University

#### Color Space Standardization And Image Analysis For High-Throughput Phenotyping Of Sorghum Bicolor, Alexandria A. Pokorny

##### Annual Symposium on Biomathematics and Ecology: Education and Research

No abstract provided.

A Mathematical Model Of The Inflammatory Response To Pathogen Challenge, 2018 University of Richmond

#### A Mathematical Model Of The Inflammatory Response To Pathogen Challenge, Lester Caudill, Fiona Lynch

##### Annual Symposium on Biomathematics and Ecology: Education and Research

No abstract provided.

Transformations On Double Occurrence Words Motivated By Dna Rearrangement, 2018 University of South Florida

#### Transformations On Double Occurrence Words Motivated By Dna Rearrangement, Daniel Cruz, Margherita Maria Ferrari, Lukas Nabergall, Natasa Jonoska, Masahico Saito

##### Annual Symposium on Biomathematics and Ecology: Education and Research

No abstract provided.

Analyzing Bigger Networks With Polynomial Algebra, 2018 Portland State University

#### Analyzing Bigger Networks With Polynomial Algebra, Ian H. Dinwoodie

##### Annual Symposium on Biomathematics and Ecology: Education and Research

No abstract provided.

2018 University of Arizona

#### Application Of Data Assimilation In Forecasting Of Influenza In The United States, Hannah Biegel

##### Annual Symposium on Biomathematics and Ecology: Education and Research

No abstract provided.

Semi-Tensor Product Representations Of Boolean Networks, 2018 Illinois State University

#### Semi-Tensor Product Representations Of Boolean Networks, Matthew Macauley

##### Annual Symposium on Biomathematics and Ecology: Education and Research

No abstract provided.

2018 Illinois State University

#### Modeling The Transmission Of Wolbachia In Mosquitoes For Controlling Mosquito-Borne Diseases, Zhuolin Qu

##### Annual Symposium on Biomathematics and Ecology: Education and Research

No abstract provided.

2018 Illinois State University

#### The Influence Of Canalization On The Robustness Of Finite Dynamical Systems, Claus Kadelka

##### Annual Symposium on Biomathematics and Ecology: Education and Research

No abstract provided.

Using Canalization For The Control Of Discrete Networks, 2018 University of Kentucky

#### Using Canalization For The Control Of Discrete Networks, David Murrugarra

##### Annual Symposium on Biomathematics and Ecology: Education and Research

No abstract provided.

Modeling Influenza Outbreaks On A College Campus, 2018 University of Colorado Boulder

#### Modeling Influenza Outbreaks On A College Campus, Eli Goldwyn, Subekshya Bidari

##### Annual Symposium on Biomathematics and Ecology: Education and Research

No abstract provided.