Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

2022

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 781 - 810 of 18300

Full-Text Articles in Physical Sciences and Mathematics

Direct Ink Write And Thermomechanical Characterization Of Thermoset Composites, Sergio Dante Favela Dec 2022

Direct Ink Write And Thermomechanical Characterization Of Thermoset Composites, Sergio Dante Favela

Open Access Theses & Dissertations

This research will be divided into two sections. The first section discusses direct ink writing and thermomechanical characterization for thermoset composites. The thermoset ink is prepared with fillers aiding the printing process by modifying the rheology of the ink and geometry retention by allowing for the part to have an initial UV cure step. Three specimen formulations with different weight percentages were printed by material extrusion in the shape of tensile specimens following ASTM standard D638 to characterize the mechanical properties at room temperature, 100â?? and 200â??. Furthermore, the ink resin was characterized through DSC, TGA, and rheology testing. The …


Two-Step Single Qubit Gates For Superconducting Qubits, Edward Takyi Dec 2022

Two-Step Single Qubit Gates For Superconducting Qubits, Edward Takyi

Open Access Theses & Dissertations

Why quantum information processing? Contemporary manipulation and transmission of information is executed through physical machines (computers, routers, scanners, etc.) in which Classical Mechanics is used to describe the embodiment and transformation of information. However, the physical theory of the world is not Classical Mechanics. And so, there is no reason to suppose that machines following the laws of Classical Mechanics would have the same computational power like quantum machines. Quantum computers would break the rules of classical computers and they would be able solve problems that are intractable on conventional supercomputers.

In order to fabricate quantum computers and make significant …


Using Ground Penetrating Radar To Investigate Controls On Pedogenic Calcium Carbonate Distribution In Dryland Critical Zones, Nohemi Valenzuela Garay Dec 2022

Using Ground Penetrating Radar To Investigate Controls On Pedogenic Calcium Carbonate Distribution In Dryland Critical Zones, Nohemi Valenzuela Garay

Open Access Theses & Dissertations

Caliche or pedogenic calcium carbonate (CaCO3) layers are a common feature of arid soils, but the environmental controls on their distribution are not fully understood. Caliche layers are thought to play an important role in shallow subsurface water storage and movement, due to their water retention capacity and ability to impede vertical water transport (Hennessy et al., 1983). Therefore, caliche distribution and stability play a role in controlling water distribution in arid lands. However, due to its largely subsurface nature, caliche can be difficult to investigate and map without significant effort. I hypothesize that noninvasive geophysical methods, such as ground-penetrating …


Investigating 9-1-1 Call Experience For Medical Emergencies For Future Design, Leanna Machado Dec 2022

Investigating 9-1-1 Call Experience For Medical Emergencies For Future Design, Leanna Machado

Honors College Theses

Emergency calling services have continued to use the 9-1-1 phone number to share information about a medical emergency for around 60 years. However, there are limitations to the current emergency call services that can have improved communication, speed, and accuracy with the implementation of advancing technology. By examining the experience and opinions of 9-1-1 medical emergency callers, we are able to investigate the design of 9-1-1 services to enhance the call experience. The major challenges found in the study are difficulty in verbally explaining the emergency situation and difficulty in describing the location of the emergency. Technologies such as location …


Analytical Techniques For The Analysis Of Uranium Bearing Materials, Nathaniel D. Fletcher Dec 2022

Analytical Techniques For The Analysis Of Uranium Bearing Materials, Nathaniel D. Fletcher

Doctoral Dissertations

The interest in the use of nuclear power has increased drastically in recent years. This is due to significantly increased efficiency at producing energy when compared to fossil fuels. With the increased use of nuclear power comes an increased need to for monitor for uranium bearing materials outside of regulatory control. This dissertation covers four projects aimed at improving the analysis of these materials. The first projects aims to develop a method that allows for the analysis of elements that exist in nature as anions by triple quadrupole ICP – MS. This would allow for the ability to measure more …


Obstacles In Learning Algorithm Run-Time Complexity Analysis, Bailey Licht Dec 2022

Obstacles In Learning Algorithm Run-Time Complexity Analysis, Bailey Licht

Theses/Capstones/Creative Projects

Algorithm run-time complexity analysis is an important topic in data structures and algorithms courses, but it is also a topic that many students struggle with. Commonly cited difficulties include the necessary mathematical background knowledge, the abstract nature of the topic, and the presentation style of the material. Analyzing the subject of algorithm analysis using multiple learning theories shows that course materials often leave out key steps in the learning process and neglect certain learning styles. Students can be more successful at learning algorithm run-time complexity analysis if these missing stages and learning styles are addressed.


2022 Fall Engr333 Poster, Section B, Nicholas Paternoster, Nick Grossman, Jared Ruba, Zac Runhaar, Caleb Styf, Anne Ghata, Micah Lee, Thomas Noble, Liam Austin, Kai Barboza, Mark Bekhet, Jordan Tuter, Jacob Tanis, Sara Vansolkema, Aidan Bakker, Ben Casey, Sarah Maccarthy, Elise Miera, Christine Vanoyen Dec 2022

2022 Fall Engr333 Poster, Section B, Nicholas Paternoster, Nick Grossman, Jared Ruba, Zac Runhaar, Caleb Styf, Anne Ghata, Micah Lee, Thomas Noble, Liam Austin, Kai Barboza, Mark Bekhet, Jordan Tuter, Jacob Tanis, Sara Vansolkema, Aidan Bakker, Ben Casey, Sarah Maccarthy, Elise Miera, Christine Vanoyen

ENGR 333

  • “What would it take to eliminate Calvin's natural gas-related net CO2 emissions?”
  • Former Calvin President Michael Le Roy signed the President’s Climate Commitment on Dec 6, 2017
  • Pledged carbon neutrality by 2057
  • Results so far have been mixed due to the COVID-19 pandemic, but gains have come from: Improved lighting efficiency, Reduced enrollment, Renewable electricity is already being tackled through partnerships with companies like Sun FundED.


2022 Fall Engr333 Poster, Section A, Dat Cao, Izuchi Ebeku, Samuel Hoover, Sawyer Masselink, Ian Vanderkooi, Matthew Carlson, Jacob Heeres, Anthony Nykamp, Jacob Vanwyngarden, Nate Anderson, Anna Giboney, Gia Mien Le, Jonathan Washburn, Jess Camp, Ryan Macintyre, Aubree Peters, Alin Stoica, Drew Stoneburner, Claire Sheppard, Alayna Spiering, Reid Veneman, James Viel Dec 2022

2022 Fall Engr333 Poster, Section A, Dat Cao, Izuchi Ebeku, Samuel Hoover, Sawyer Masselink, Ian Vanderkooi, Matthew Carlson, Jacob Heeres, Anthony Nykamp, Jacob Vanwyngarden, Nate Anderson, Anna Giboney, Gia Mien Le, Jonathan Washburn, Jess Camp, Ryan Macintyre, Aubree Peters, Alin Stoica, Drew Stoneburner, Claire Sheppard, Alayna Spiering, Reid Veneman, James Viel

ENGR 333

In 2017 President Michael K. Le Roy signed Second Nature’s President Climate Commitment. This commitment outlines that Calvin’s governing body will ensure Calvin University is a carbon neutral educational institution by 2057. In June of 2022, Calvin University’s presidential seat was passed from Dr. Michael K. Le Roy to Dr. Wiebe Boer. In his short time as the president of Calvin University, Dr. Boer has put many projects into motion to help Calvin achieve its goal of becoming carbon neutral by 2057. This past fall Dr. Boer tasked the ENGR 333 class with answering the following question: What would it …


How Viscosity Of An Asphalt Binder Depends On Temperature: Theoretical Explanation Of An Empirical Dependence, Edgar Daniel Rodriguez Velasquez, Vladik Kreinovich Dec 2022

How Viscosity Of An Asphalt Binder Depends On Temperature: Theoretical Explanation Of An Empirical Dependence, Edgar Daniel Rodriguez Velasquez, Vladik Kreinovich

Departmental Technical Reports (CS)

Pavement must be adequate for all the temperatures, ranging from the winter cold to the summer heat. In particular, this means that for all possible temperatures, the viscosity of the asphalt binder must stay within the desired bounds. To predict how the designed pavement will behave under different temperatures, it is desirable to have a general idea of how viscosity changes with temperature. Pavement engineers have come up with an empirical approximate formula describing this change. However, since this formula is purely empirical, with no theoretical justification, practitioners are often somewhat reluctant to depend on this formula. In this paper, …


Graph Approach To Uncertainty Quantification, Hector A. Reyes, Cliff Joslyn, Vladik Kreinovich Dec 2022

Graph Approach To Uncertainty Quantification, Hector A. Reyes, Cliff Joslyn, Vladik Kreinovich

Departmental Technical Reports (CS)

Traditional analysis of uncertainty of the result of data processing assumes that all measurement errors are independent. In reality, there may be common factor affecting these errors, so these errors may be dependent. In such cases, the independence assumption may lead to underestimation of uncertainty. In such cases, a guaranteed way to be on the safe side is to make no assumption about independence at all. In practice, however, we may have information that a few pairs of measurement errors are indeed independent -- while we still have no information about all other pairs. Alternatively, we may suspect that for …


Will Nanotechnology Bring In The Judgement Day?, Olga Kosheleva, Vladik Kreinovich Dec 2022

Will Nanotechnology Bring In The Judgement Day?, Olga Kosheleva, Vladik Kreinovich

Departmental Technical Reports (CS)

There are many current and prospective positive aspects of nanotechnology. However, while we look forward to its future successes, we need to keep our eyes open and be prepared for what will really be a future shock: that quantum computing – an inevitable part of nanotechnology – will enable the future folks to read all our encrypted messages and thus, learn everything that we wanted to keep secret. This will be really the Judgement Day, when all our sins will be open to everyone. How we will react to it? Will this destroy our civilization? Let us hope that the …


An Argument In Favor Of Piecewise-Constant Membership Functions, Marina Tuyako Mizukoshi, Weldon Lodwick, Martine Ceberio, Olga Kosheleva, Vladik Kreinovich Dec 2022

An Argument In Favor Of Piecewise-Constant Membership Functions, Marina Tuyako Mizukoshi, Weldon Lodwick, Martine Ceberio, Olga Kosheleva, Vladik Kreinovich

Departmental Technical Reports (CS)

Theoretically, we can have membership functions of arbitrary shape. However, in practice, at any given moment of time, we can only represent finitely many parameters in a computer. As a result, we usually restrict ourselves to finite-parametric families of membership functions. The most widely used families are piecewise linear ones, e.g., triangular and trapezoid membership functions. The problem with these families is that if we know a nonlinear relation y = f(x) between quantities, the corresponding relation between membership functions is only approximate -- since for piecewise linear membership functions for x, the resulting membership function for y is not …


Epistemic Vs. Aleatory: Case Of Interval Uncertainty, Marina Tuyako Mizukoshi, Weldon Lodwick, Martine Ceberio, Vladik Kreinovich Dec 2022

Epistemic Vs. Aleatory: Case Of Interval Uncertainty, Marina Tuyako Mizukoshi, Weldon Lodwick, Martine Ceberio, Vladik Kreinovich

Departmental Technical Reports (CS)

Interval computations usually deal with the case of epistemic uncertainty, when the only information that we have about a value of a quantity is that this value is contained in a given interval. However, intervals can also represent aleatory uncertainty -- when we know that each value from this interval is actually attained for some object at some moment of time. In this paper, we analyze how to take such aleatory uncertainty into account when processing data. We show that in case when different quantities are independent, we can use the same formulas for dealing with aleatory uncertainty as we …


Scaling Investment In Renewable Energy Generation To Achieve Sustainable Development Goals 7 (Affordable And Clean Energy) And 13 (Climate Action) And The Paris Agreement: Roadblocks And Drivers, Mithatcan Aydos, Perrine Toledano, Martin Dietrich Brauch, Ladan Mehranvar, Theodoros Iliopoulos, Sunayana Sasmal Dec 2022

Scaling Investment In Renewable Energy Generation To Achieve Sustainable Development Goals 7 (Affordable And Clean Energy) And 13 (Climate Action) And The Paris Agreement: Roadblocks And Drivers, Mithatcan Aydos, Perrine Toledano, Martin Dietrich Brauch, Ladan Mehranvar, Theodoros Iliopoulos, Sunayana Sasmal

Columbia Center on Sustainable Investment

The zero-carbon energy transition is the solution to the 2022 energy crisis and a fundamental part of the solution to the global climate crisis. Yet, there are relatively low levels of investment in renewable energy in developing countries, hindering their achievement of the Sustainable Development Goals (SDGs) and contribution to the Paris Agreement goals.

In 2021, the Asia–Pacific region (excluding China) accounted for less than 8% of investments in energy transition technologies, Latin America and the Caribbean for less than 4%, and Africa and the Middle East for less than 2%. Annual investment in zero-carbon energy in developing economies other …


Make Your Own Sprites: Aliasing-Aware And Cell-Controllable Pixelization, Zongwei Wu, Liangyu Chai, Nanxuan Zhao, Bailin Deng, Yongtuo Liu, Qiang Wen, Junle Wang, Shengfeng He Dec 2022

Make Your Own Sprites: Aliasing-Aware And Cell-Controllable Pixelization, Zongwei Wu, Liangyu Chai, Nanxuan Zhao, Bailin Deng, Yongtuo Liu, Qiang Wen, Junle Wang, Shengfeng He

Research Collection School Of Computing and Information Systems

Pixel art is a unique art style with the appearance of low resolution images. In this paper, we propose a data-driven pixelization method that can produce sharp and crisp cell effects with controllable cell sizes. Our approach overcomes the limitation of existing learning-based methods in cell size control by introducing a reference pixel art to explicitly regularize the cell structure. In particular, the cell structure features of the reference pixel art are used as an auxiliary input for the pixelization process, and for measuring the style similarity between the generated result and the reference pixel art. Furthermore, we disentangle the …


Graviweak Theory In Bicomformal Space, Mubarak Ukashat Dec 2022

Graviweak Theory In Bicomformal Space, Mubarak Ukashat

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

There are four basic forces in nature: the electromagnetic force, which accounts for interactions of particles with charges; the weak force, which is responsible for radioactive decay; the strong force, which holds the particles inside a nucleus tightly bound together; and the gravitational force, which is responsible for keeping us on our beautiful planet, Earth and holding together our entire solar system. Physicists have been on the hunt for a theory that can single-handedly explain all these forces under the same underlying mathematical formulation. So far, physicists have suceeded in unifying the electromagnetic and weak forces in what is called …


Data Visualization, Dimensionality Reduction, And Data Alignment Via Manifold Learning, Andrés Felipe Duque Correa Dec 2022

Data Visualization, Dimensionality Reduction, And Data Alignment Via Manifold Learning, Andrés Felipe Duque Correa

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The high dimensionality of modern data introduces significant challenges in descriptive and exploratory data analysis. These challenges gave rise to extensive work on dimensionality reduction and manifold learning aiming to provide low dimensional representations that preserve or uncover intrinsic patterns and structures in the data. In this thesis, we expand the current literature in manifold learning developing two methods called DIG (Dynamical Information Geometry) and GRAE (Geometry Regularized Autoencoders). DIG is a method capable of finding low-dimensional representations of high-frequency multivariate time series data, especially suited for visualization. GRAE is a general framework which splices the well-established machinery from kernel …


Temperature Dependent Density Of States Models And Compiled Data For Radiation Induced Conductivity, Jodie Gillespie Dec 2022

Temperature Dependent Density Of States Models And Compiled Data For Radiation Induced Conductivity, Jodie Gillespie

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Radiation Induced Conductivity (RIC) is the change in conductivity of a material due to bombardment from incident high energy radiation. RIC has consistently been found to follow a standard power law relation, 𝜎𝑅𝐼𝐶(𝑇) = 𝑘𝑅𝐼𝐶(𝑇)∆(𝑇), between conductivity, 𝜎𝑅𝐼𝐶 and adsorbed dose rate, . 𝑘𝑅𝐼𝐶(𝑇) and ∆(𝑇) are material dependent parameters. Previous RIC models were developed in the 𝑇 → 0 limit. Now expanded models are developed in the low temperature limit (within a few 𝑘𝐵𝑇 of the effective Fermi level) by approximating the Fermi-Dirac equation within a …


River Response To Sediment Supply: The Sand Bed Case, Christina M. Leonard Dec 2022

River Response To Sediment Supply: The Sand Bed Case, Christina M. Leonard

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Effective management of in-channel and floodplain habitat requires an ability to forecast river response to changes in water and sediment supply. These changes may result from dam construction/decommissioning, changes in reservoir operations, or changes in grazing or forestry practices. If a change in water and sediment supply causes sediment to be delivered faster than the channel’s capacity to transport it, sediment will accumulate in the reach, leading to changes in channel form and increasing the potential for flooding. A decrease in sediment supply relative to transport capacity can lead to channel incision. The extent and timing of sediment accumulation or …


Design Of Environment Aware Planning Heuristics For Complex Navigation Objectives, Carter D. Bailey Dec 2022

Design Of Environment Aware Planning Heuristics For Complex Navigation Objectives, Carter D. Bailey

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A heuristic is the simplified approximations that helps guide a planner in deducing the best way to move forward. Heuristics are valued in many modern AI algorithms and decision-making architectures due to their ability to drastically reduce computation time. Particularly in robotics, path planning heuristics are widely leveraged to aid in navigation and exploration. As the robotic platform explores and navigates, information about the world can and should be used to augment and update the heuristic to guide solutions. Complex heuristics that can account for environmental factors, robot capabilities, and desired actions provide optimal results with little wasted exploration, but …


Relativistic, Continuum Drift-Kinetic Capability In The Nimrod Plasma Fluid Code, Tyler Markham Dec 2022

Relativistic, Continuum Drift-Kinetic Capability In The Nimrod Plasma Fluid Code, Tyler Markham

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A ”runaway” electron is an electron that, through a self-reinforcing process, accelerates to relativistic speeds. At multiple points during tokamak discharges, relativistic runaway electron (RE) beams can form. RE beams pose a serious risk in the form of severe damage to plasma facing components in ITER and future burning plasma reactors. Early RE studies used simplified geometric and transport models, but enabled feedback on the overall plasma evolution. This feedback is important for understanding the evolution of the RE current column. The work in this thesis is an important step toward self-consistently evolving an RE distribution in the plasma fluid …


Tethered Axial Coordination As A Control Modality In Rhodium(Ii)-Catalyzed Carbene Transfer Reactions, Anthony Dean Abshire Dec 2022

Tethered Axial Coordination As A Control Modality In Rhodium(Ii)-Catalyzed Carbene Transfer Reactions, Anthony Dean Abshire

Doctoral Dissertations

Rhodium(II) paddlewheels are versatile carbene transfer catalyst that are broadly applied in insertion reactions, cycloadditions, and ylide transformations. The effects of axial coordination in rhodium(II)-catalyzed carbene transfer reactions are still little understood due to compounding factors that are difficult to isolate. Traditionally, researchers study axial coordination by addition of Lewis base additives. To ensure interaction between the Lewis base and catalyst, high molar equivalents are used. This can also have the undesired effect of hampering the activity of the catalyst and suppressing the yield of the reaction. We have developed ligands with a tethered Lewis base to overcome these issues. …


Experimental Approaches To Evaluating Silicate Melt Properties And Trace Element Fractionation During Crystallization At High Pressures And High Temperatures, Megan D. Mouser Dec 2022

Experimental Approaches To Evaluating Silicate Melt Properties And Trace Element Fractionation During Crystallization At High Pressures And High Temperatures, Megan D. Mouser

Doctoral Dissertations

Current understanding of the evolution and behavior of silicate materials that form in planetary interiors at high-pressures and high-temperatures largely come from experimental work as natural samples are either rare, or physically inaccessible. Laboratory experiments provide a comprehensive way to constrain the crystallization history, elemental partitioning, and viscosity of different silicate materials at planetary mantle pressure and temperature conditions. This work utilizes two high-pressure experimental techniques, the Paris-Edinburgh apparatus, and the piston cylinder apparatus, to measure physical and chemical properties of silicate materials. The viscosity of reduced, Fe-free silicate liquids, with and without sulfur (S-free and S-bearing), were measured to …


Imaging Normal Fluid Flow In He Ii With Neutrons And Lasers — A New Application Of Neutron Beams For Studies Of Turbulence, Xin Wen Dec 2022

Imaging Normal Fluid Flow In He Ii With Neutrons And Lasers — A New Application Of Neutron Beams For Studies Of Turbulence, Xin Wen

Doctoral Dissertations

Turbulence is ubiquitous in life —from biology to astrophysics. The best direct numeric simulations (DNS) have only been benchmarked against low resolution, time-averaged experimental configurations—partly because of limitations in computing power. With time, computing power has greatly increased, so there is need for higher quality data of turbulent flow. In this dissertation, we explore a solution that enables quantitative visualization measurement of the velocity field in liquid helium, which has the potential of breaking new ground for high Reynolds number turbulence research and model testing.

Our technique involves creation of clouds of molecular tracers using 3He-neutron absorption reaction in liquid …


Developing And Facilitating Temporary Team Mental Models Through An Information-Sharing Recommender System, Geoffrey Musick Dec 2022

Developing And Facilitating Temporary Team Mental Models Through An Information-Sharing Recommender System, Geoffrey Musick

All Dissertations

It is well understood that teams are essential and common in many aspects of life, both work and leisure. Due to the importance of teams, much research attention has focused on how to improve team processes and outcomes. Of particular interest are the cognitive aspects of teamwork including team mental models (TMMs). Among many other benefits, TMMs involve team members forming a compatible understanding of the task and team in order to more efficiently make decisions. This understanding is sometimes classified using four TMM domains: equipment (e.g., operating procedures), task (e.g., strategies), team interactions (e.g., interdependencies) and teammates (e.g., tendencies). …


Carbon Sinks And Sources In Great Salt Lake: Consequences Of Declining Lake Levels, Melissa Cobo Arias Dec 2022

Carbon Sinks And Sources In Great Salt Lake: Consequences Of Declining Lake Levels, Melissa Cobo Arias

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Globally, saline lakes are experiencing declining water level as a consequence of climate change, water diversions for human consumption, and management strategies that do not account for changing climate and drought conditions. Great Salt Lake (GSL) is a large saline lake in Utah, USA, and is, as most saline lakes, experiencing decreasing lake levels which may impact local carbon cycling. It is unknown how lakebed drying affects processes that control carbon sequestration and carbon emissions to the atmosphere. The goal of this research was to measure various biological processes that use, create, and transform carbon in GSL to understand the …


On Variants Of Sliding And Frank-Wolfe Type Methods And Their Applications In Video Co-Localization, Seyed Hamid Nazari Dec 2022

On Variants Of Sliding And Frank-Wolfe Type Methods And Their Applications In Video Co-Localization, Seyed Hamid Nazari

All Dissertations

In this dissertation, our main focus is to design and analyze first-order methods for computing approximate solutions to convex, smooth optimization problems over certain feasible sets. Specifically, our goal in this dissertation is to explore some variants of sliding and Frank-Wolfe (FW) type algorithms, analyze their convergence complexity, and examine their performance in numerical experiments. We achieve three accomplishments in our research results throughout this dissertation. First, we incorporate a linesearch technique to a well-known projection-free sliding algorithm, namely the conditional gradient sliding (CGS) method. Our proposed algorithm, called the conditional gradient sliding with linesearch (CGSls), does not require the …


Statistical Methods For Modern Threats, Brandon Lumsden Dec 2022

Statistical Methods For Modern Threats, Brandon Lumsden

All Dissertations

More than ever before, technology is evolving at a rapid pace across the broad spectrum of biological sciences. As data collection becomes more precise, efficient, and standardized, a demand for appropriate statistical modeling grows as well. Throughout this dissertation, we examine a variety of new age data arising from modern technology of the 21st century. We begin by employing a suite of existing statistical techniques to address research questions surrounding three medical conditions presenting in public health sciences. Here we describe the techniques used, including generalized linear models and longitudinal models, and we summarize the significant associations identified between research …


Lindley Processes With Correlated Changes, John Grant Dec 2022

Lindley Processes With Correlated Changes, John Grant

All Dissertations

This dissertation studies a Lindley random walk model when the increment process driving the walk is strictly stationary. Lindley random walks govern customer waiting times in many queueing models and several natural and business processes, including snow depths, frozen soil depths, inventory quantities, etc. Probabilistic properties of a Lindley process with time-correlated stationary changes are explored. We provide a streamlined argument that the process admits a limiting stationary distribution when the mean of the incremental changes is negative and that the Lindley process is strictly stationary when starting from this stationary distribution. The Markov characteristics of the process are explored …


Pasta: Table-Operations Aware Fact Verification Via Sentence-Table Cloze Pre-Training, Zihui Gu, Ju Fan, Nan Tang, Preslav Nakov, Xiaoman Zhao, Xiaoyong Du Dec 2022

Pasta: Table-Operations Aware Fact Verification Via Sentence-Table Cloze Pre-Training, Zihui Gu, Ju Fan, Nan Tang, Preslav Nakov, Xiaoman Zhao, Xiaoyong Du

Natural Language Processing Faculty Publications

Fact verification has attracted a lot of research attention recently, e.g., in journalism, marketing, and policymaking, as misinformation and disinformation online can sway one's opinion and affect one's actions. While fact-checking is a hard task in general, in many cases, false statements can be easily debunked based on analytics over tables with reliable information. Hence, table-based fact verification has recently emerged as an important and growing research area. Yet, progress has been limited due to the lack of datasets that can be used to pre-train language models (LMs) to be aware of common table operations, such as aggregating a column …