Porting WarpX to GPU accelerated platforms

WarpX is a general purpose electromagnetic particle-in-cell code that was originally designed to run on many-core CPU architectures . We describe the strategy followed to allow WarpX to use the GPU-accelerated nodes on OLCF’sSummit supercomputer . We believe this strategy will extend to the upcoming Frontier and Aurora supercomputers .…

GPU Optimization for High Quality Kinetic Fluid Simulation

Fluid simulations are often performed using the incompressible Navier-Stokesequations (INSE), leading to sparse linear systems which are difficult to solveefficiently in parallel . Recently, kinetic methods based on theadaptive-central-moment multiple-relaxation-time (ACM-MRT) model havedemonstrated impressive capabilities to simulate both laminar and turbulentflows, with quality matching or surpassing that of state-of-the-art INSE solvers .…

Early insights into the Arabic Citation Index

The Arabic Citation Index (ARCI) was launched in 2020 . As of October 2020, ARCI indexed 65,208 records covering the 2015-2019 period . Close to 99% of documents indexed are articles . Results reveal theconcentration of publications in the Arts & Humanities and Social Sciencesfields .…

BIP DB A Dataset of Impact Measures for Scientific Publications

BIP! DB is an open dataset that contains a variety of impact measures calculated for a large collection of more than 100 million scientific publications from various disciplines . The growth rate of the number of scientific publications is constantly creating challenges in the identification of valuableresearch and in various scholarly data management applications, in general .…

A Spectral Approach to Polytope Diameter

We prove upper bounds on the graph diameters of polytopes in two settings . The bounds rely on spectral techniques — applied to a certain matrix and a certain continuous time Markov chain . Thenecessary spectral gap bounds arise from the log-concavity of the volume of an asimple polytope in terms of its slack variables .…

Random Graph Matching with Improved Noise Robustness

Graph matching, also known as network alignment, refers to finding abijection between the vertices of two given graphs so as to maximally aligntheir edges . This fundamental computational problem arises frequently in fields such as computer vision and biology . Recently, there has been aplethora of work studying efficient algorithms for graph matching underprobabilistic models .…

Continuous One Counter Automata

We study the reachability problem for continuous one-counter automata, COCAfor short . In such automata transitions are guarded by upper and lower boundtests against the counter value . We claim the problem is decidable in polynomialtime . We also claim that the problem can be (non-deterministically) scaled down by a nonzerofactor between zero and one .…

Equilibrium Learning in Combinatorial Auctions Computing Approximate Bayesian Nash Equilibria via Pseudogradient Dynamics

Bayesian Nash equilibria (BNE) remain poorlyunderstood . Analytical solutions are known only for a few cases where the problem can be reformulated as a tractable partial differential equation (PDE) In this study, we present a scalable alternative multi-agent equilibrium learning method that represents strategies as neural networks and applies policy iteration based on gradient dynamics in self-play .…

Symmetric equilibrium of multi agent reinforcement learning in repeated prisoner s dilemma

We investigate the repeated prisoner’s dilemma game where both players use reinforcement learning to obtain their optimal memory-onestrategies . We theoretically solve the joint Bellman optimum equations ofreinforcement learning . We find that the Win-stay Lose-shift strategy, the Grimstrategy, and the strategy which always defects can form symmetric equilibrium of the mutual reinforcement learning process .…

Participatory Funding Coordination Model Axioms and Rules

We present a new model of collective decision making that captures important crowd-funding and donor coordination scenarios . We identify meaningful axioms that capture concerns including fairness, efficiency, and participation incentives . An experimental study indicates the relative performance of different rules as well as the price of enforcing fairness axiom .…

WallStreetBets Positions or Ban

r/wallstreetbets (WallStreetBets or WSB) is a subreddit devoted to irreverentmemes and high-risk options trading . As of March 30, 2020, the subreddit boasts a usership of nearly 1.1 millions subscribers and self-describes as “if 4chanfound a Bloomberg terminal” This paper will utilize Amy Jo Kim’s community design principles along with social psychology theory as frameworks tounderstand how this chaotic, oftentimes offensive community has developed one of the largest and most loyal user bases on the platform .…

Visualization of Nonlinear Programming for Robot Motion Planning

Nonlinear programming targets nonlinear optimization with constraints, which involves humans for problem modeling and algorithms for problem solving . We address the challenge of handling, understanding, and trouble-shooting high-dimensional optimization with a large number of constraints . We report on the experiences from thisdesign study, illustrate the usefulness for relevant example cases, and discussthe extension to visual analytics for nonlinear programming in general .…

AHMoSe A Knowledge Based Visual Support System for Selecting Regression Machine Learning Models

Decision support systems have become increasingly popular in the domain of agriculture . AHMoSe is a visual support system that allows experts to better understand, diagnose and compare different regression models, primarily by enriching model-agnostic explanations with domain knowledge . We describe a use case scenario in theviticulture domain, grape quality prediction, where the system enables users to select prediction models that perform better.…

HEMVIP Human Evaluation of Multiple Videos in Parallel

In many research areas, objectivemeasures alone do not provide an accurate impression of key stimulus traits such as perceived quality or appropriateness . The gold standard is instead toevaluate these aspects through user studies, especially subjective evaluationsof video stimuli . The time and resources required for suchevaluations scale poorly as the number of conditions to be compared increases .…

Exploring Lightweight Interventions at Posting Time to Reduce the Sharing of Misinformation on Social Media

When users on social media share content without considering its veracity, they may unwittingly be spreading misinformation . Such assessment may deter users from posting misinformation in the first place, authors say . Findings have implications for designing social media and news sharing platforms that draw from richer signals of content credibility, they say .…

Not Now Ask Later Users Weaken Their Behavior Change Regimen Over Time But Expect To Re Strengthen It Imminently

How effectively do we adhere to nudges and interventions that help us control our online browsing habits? If we have a temporary lapse and disable thebehavior change system, do we later resume our adherence, or has the dambroken? In this paper, we investigate these questions through log analyses of 8,000+ users on HabitLab, a behavior change platform that helps users reduce their time online .…

Type Based Analysis of Logarithmic Amortised Complexity

We introduce a novel amortised resource analysis couched in a type-and-effect system . Our analysis is formulated in terms of the physicist’s method ofamortised analysis, and is potential-based . The type system makes use of potential functions and is the first such system to exhibit*logarithmic complexity*.…

Alignment Completeness for Relational Hoare Logics

Relational Hoare logics (RHL) provide rules for reasoning about relations between programs . Several RHLs include a rule, Sequential-Product, that infers a relational correctness judgment from judgments of ordinary Hoare logic (HL) Alignment completeness results are given to account for several different setsof rules .…

Agent Based Virus Model using NetLogo Infection Propagation Precaution Recovery Multi site Mobility and Un Lockdown

This paper presents a novel virus propagation model using NetLogo . The model allows agents to move across multiple sites using different routes . Routes can be configured, enabled for mobility and (un)locked down independently . Agents can getinfected, propagate their infections to others, can take precautions againstinfection and also subsequently recover from infection .…

Detecting Deepfake Videos Using Euler Video Magnification

Recent advances in artificial intelligence make it hard to distinguish between genuine and counterfeit media, especially images and videos . Deepfake videos are based onmanipulating videos using advanced machine learning techniques . This involves replacing the face of an individual from a source video with a second person, in the destination video .…

Bayesian Paired Comparison with the bpcs Package

This article introduces the bpcs R package (Bayesian Paired Comparison inStan) and the statistical models implemented in the package . The goal of thispackage is to facilitate the use of Bayesian models for paired comparison datain behavioral research . Bayesiandata analyses are less sensitive to optional stopping, have better control of type I error, have stronger evidence towards the null hypothesis .…

An Analysis Of Protected Health Information Leakage In Deep Learning Based De Identification Algorithms

Modern deep learning algorithms have the highest potential of suchleakage due to complexity of the models . Recent research in the field has highlighted such issues in non-medical data, but all analysis is likely to bedata and algorithm specific . Results indicate that the model does not provide any strong evidence intothe identification of the individuals in the training data set and there is notyet empirical evidence it is unsafe to distribute the model for general use .…

Projection based model reduction for the immersed boundary method

Fluid-structure interactions are central to many bio-molecular processes . In this paper, we consider the immersed boundary method (IBM) for biofluid systems . We apply reduced-order techniques to eliminate degrees of freedom associated with a large number of fluidvariables . We show how reduced models can be derived using Petrov-Galerkinprojection and subspaces that maintain the incompressibility condition .…

Reproducing kernel Hilbert spaces polynomials and the classical moment problems

We show that polynomials do not belong to the reproducing kernel Hilbertspace of infinitely differentiable translation-invariant kernels whose spectral measures have moments corresponding to a determinate moment problem . Our proof is based on relating this question to the problem of best linear estimation incontinuous time one-parameter regression models with a stationary error process defined by the kernel .…

Stagnation Detection with Randomized Local Search

$SD-(1+1)EA$ introduced by Rajabi andWitt (GECCO 2020) adds stagnation detection to the classical $(1-EA$ with standard bit mutation . Stagnance detection adjusts the mutation rate of evolutionary algorithms when they encounter local optima . We propose additional schemes that prevent infinite optimization times even if the algorithm misses a workingchoice of $k$ due to unlucky events .…

BENDR using transformers and a contrastive self supervised learning task to learn from massive amounts of EEG data

Deep neural networks (DNNs) used for brain-computer-interface (BCI) classification are commonly expected to learn general features when trained across a variety of contexts . While some success is found in such an approach, we suggest that this interpretation is limited and an alternative would better leveragethe newly (publicly) available massive EEG datasets .…

Safety Verification of Parameterized Systems under Release Acquire

We study safety verification problem for parameterized systems under therelease-acquire (RA) semantics . It has been shown that the problem isintractable for systems with unlimited access to atomic compare-and-swap (CAS)instructions . We show that safety verification is only \pspace-complete for the bounded modelchecking problem where the distinguished threads are loop-free.…