## The Anarchy Stability Tradeoff in Congestion Games

This work focuses on the design of incentive mechanisms in congestion games . Our main result provides a characterization of this tradeoff interms of upper and lower bounds on the Pareto frontier between the price ofanarchy and price of stability .…

## On the Impact of Information Acquisition and Aftermarkets on Auction Efficiency

A common assumption in auction theory is that the information available to agents is given exogenously and that the auctioneer has full control over the market . We show that if an auction is smooth (e.g., first-price auction, all-pay auction), then the corresponding price of anarchy bound due to smoothness continues to hold in any environment with (a) information acquisition onopponents’ valuations, and/or (b) an aftermarket satisfying two mild conditions(voluntary participation and weak budget balance) We also consider the specialcase with two ex ante symmetric bidders, where the first- price auction is knownto be efficient in isolation .…

## ProGS Property Graph Shapes Language Extended Version

Property graphs constitute data models for representing knowledge graphs . They allow for the convenient representation of facts, including facts about facts, represented by triples in subject or object position of other triples . In RDF representations, this error can be addressed by shapelanguages such as SHACL or ShEx .…

## A Projector Camera System Using Hybrid Pixels with Projection and Capturing Capabilities

We propose a novel projector-camera system (ProCams) in which each pixel has both projection and capturing capabilities . We implemented a proof-of-concept ProCams prototype anddemonstrated its applicability to a dynamic projection mapping .…

## Contrastive Learning for Cold Start Recommendation

Recommending cold-start items is a long-standing and fundamental challenge inrecommender systems . CFscheme fails to use collaborative signals to infer user preference on these items . CLCRec aims to maximize themutual dependencies between item content and collaborative signals . It allows us to preserve collaborative signals in the content representations in thecontent representations for both warm and cold start items .…

## Separating LREC from LFP

LREC= is an extension of first-order logic with a logarithmic recursion operator . It was introduced by Grohe et al. and shown to capture complexityclass L over trees and interval graphs . It does not capture L in general as it is contained in FPC – fixed-point logic with counting .…

## Giotto ph A Python Library for High Performance Computation of Persistent Homology of Vietoris Rips Filtrations

giotto-ph is based on Morozov andNigmetov’s lockfree (multicore) implementation of Ulrich Bauer’s Ripser package . It also contains a re-implementation of Boissonnat and Pritam’s “EdgeCollapser”, implemented so far only in the GUDHI library . The final implementation of our persistent homology backend establishes a new state ofthe art, surpassing even GPU-accelerated implementations such as Ripsing when using as few as 5–10 CPU cores .…

## EduCOR An Educational and Career Oriented Recommendation Ontology

EduCOR is an educational, career-oriented ontology that provides a foundation for representing online learning resources for personalised learning systems . The EduCOR ontology is designed to enable learningmaterial repositories to offer learning path recommendations . It is designed for the user’s learning goals, academic and psychological parameters, and the labour-market skills .…

## Incremental Vulnerability Detection via Back Propagating Symbolic Execution of Insecurity Separation Logic

We present the first compositional, incremental static analysis for detectingmemory-safety and information leakage vulnerabilities in C-like programs . We develop the first under-approximate relational program logics, including InsecSL . We show how InSecSL can be automated viaback-propagating symbolic execution (BPSE) to build a bottom-up,inter-procedural and incremental analysis .…

## Finding a Maximum Clique in a Grounded 1 Bend String Graph

A grounded 1-bend string graph is an intersection graph of a set of polygonallines, each with one bend, such that the lines lie above a common horizontal line . We show that finding a maximum clique is APX-hard, even for strictly $y$-monotone strings .…

## PonderNet Learning to Ponder

In standard neural networks the amount of computation used grows with the size of the inputs, but not with the complexity of the problem being learnt . PonderNet learns end-to-end the number of computational steps to achieve aneffective compromise between training prediction accuracy, computational cost and generalization .…

## Bounds for Multiple Packing and List Decoding Error Exponents

Multiple packing is a natural generalization of sphere packing . We revisit the problem of high-dimensional multiple packing in Euclideanspace . We study the multiplepacking problem for both bounded point sets and unbounded point sets . We derive various bounds on the largest possible density of a multiple packing .…

## Tortured phrases A dubious writing style emerging in science Evidence of critical issues affecting established journals

More complex AI-powered generation techniques produce texts indistinguishable from that of humans . Some websites offer to rewrite texts for free, generating gobbledegook full of tortured phrases . We believe some authors used rewrittentexts to pad their manuscripts . Deception with synthetic texts threatens the integrity of the scientific literature.…

## Inapproximability of counting hypergraph colourings

Recent developments in approximate counting have made startling progress indeveloping fast algorithmic methods for approximating the number of solutionsto constraint satisfaction problems (CSPs) with large arities . However, the boundaries of these methods for CSPs with non-Boolean domain are not well-understood .…

## ReconVAT A Semi Supervised Automatic Music Transcription Framework for Low Resource Real World Data

Most of the current supervised automatic music transcription (AMT) models lack the ability to generalize . The proposed ReconVAT usesreconstruction loss and virtual adversarial training . When combined withexisting U-net models for AMT, it achieves competitive results on common datasets such as MAPS and MusicNet .…

## Topological synchronization explosive transition and rhythmic phase

Topological signals defined on nodes, links and higher dimensional simplices define the dynamical state of a network or of a simplicial complex . The dynamics ofsignals defined on the nodes is affected by a phase lag depending on the state of nearby nodes .…

## Let s Play for Action Recognizing Activities of Daily Living by Learning from Life Simulation Video Games

Recognizing Activities of Daily Living (ADL) is a vital process forintelligent assistive robots . But collecting large annotated datasets require temporal labeling and raises privacy concerns . We build Sims4Action by specifically executingactions-of-interest in a “top-down” manner . We integrate two modern algorithms for video-based activityrecognition in our framework .…

## COPER a Query adaptable Semantics based Search Engine for Persian COVID 19 Articles

Iranian Healthcare magazines have been published in Iran to inform the public of the COVID-19 crisis . However, finding answers in this volume of information is an extremely difficult task . With the surge of pretrained language models, a new pathway has been opened to incorporate Persian text contextual information .…

## MMSys 21 Grand Challenge on Detecting Cheapfakes

Cheapfake is a recently coined term that encompasses non-AI (“cheap”)manipulations of multimedia content . Cheapfakes are known to be more prevalent than deepfakes . OOC media is much harder to detect than fake media,since the images and videos are not tampered .…

## Inapproximability of counting hypergraph colourings

Recent developments in approximate counting have made startling progress indeveloping fast algorithmic methods for approximating the number of solutionsto constraint satisfaction problems (CSPs) with large arities . However, the boundaries of these methods for CSPs with non-Boolean domain are not well-understood .…

## On the Computational Complexity of the Chain Rule of Differential Calculus

Many modern numerical methods in computational science and engineering rely on derivatives of mathematical models for the phenomena under investigation . The computation of these derivatives often represents the bottleneck in termsof overall runtime performance . The chain rule of differentiation is the fundamental prerequisite for computing accurate derivatives of composite functions which perform apotentially very large number of elemental function evaluations .…

## Approximate Normalization and Eager Equality Checking for Gradual Inductive Families

We present a gradual dependently-typed language that supports inductive typefamilies, has decidable type-checking, and provably supports smooth migration between static and dynamic . To facilitate these checks, we define an algebraicnotion of gradual precision, axiomatizing certain semantic properties ofgradual terms .…

## MidiBERT Piano Large scale Pre training for Symbolic Music Understanding

This paper presents an attempt to employ the mask language modeling approach of BERT to pre-train a 12-layer Transformer model over 4,166 pieces of polyphonic piano MIDI files for tackling a number of symbolic-domaindiscriminative music understanding tasks . We find that, given a pre-trained Transformer, our models outperform recurrent neural network based baselines with less than 10epochs of fine-tuning .…

## Peer Selection with Noisy Assessments

In this paper we extend PeerNomination, the most accurate peer reviewing algorithm to date, into WeightedPeerNomination . We show analytically that a weighting scheme can improve the overall accuracy of the selection significantly . We explicitly formulate assessors’ reliability weights in a way that doesn’t violate strategyproofness, and use this information to reweight their scores .…

## Separating Data Examples by Description Logic Concepts with Restricted Signatures

We study the separation of positive and negative data examples in terms of description logic concepts in the presence of an ontology . We add a signature that specifies a subset of the symbols that can be used for separation .…

## ProGS Property Graph Shapes Language Extended Version

Property graphs constitute data models for representing knowledge graphs . They allow for the convenient representation of facts, including facts about facts, represented by triples in subject or object position of other triples . In RDF representations, this error can be addressed by shapelanguages such as SHACL or ShEx .…

## Finding a Maximum Clique in a Grounded 1 Bend String Graph

A grounded 1-bend string graph is an intersection graph of a set of polygonallines, each with one bend, such that the lines lie above a common horizontal line . We show that finding a maximum clique is APX-hard, even for strictly $y$-monotone strings .…

## Parallel Element based Algebraic Multigrid for H curl and H div Problems Using the ParELAG Library

This paper presents the use of element-based algebraic multigrid (AMGe)hierarchies, implemented in the ParELAG (Parallel Element AgglomerationAlgebraic Multigrid Upscaling and Solvers) library . It produces multilevelvelpreconditioners and solvers for H(curl) and H(div) formulations . This paper demonstrates some of the capabilities of the library and outlines some of its components and procedures .…

## A Splitting Scheme for Flip Free Distortion Energies

We introduce a robust optimization method for flip-free distortion energies . We exploit the special structure of distortion energies to employ an operatorsplitting technique . The scheme results in an efficient method where theglobal step involves a single matrix multiplication and the local steps are closed-form per-triangle/per-tetrahedron expressions that are highlyparallelizable .…

## How to Approximate Ontology Mediated Queries

We introduce and study several notions of approximation for ontology-mediatedqueries based on description logics ALC and ALCI . Our approximations are oftwo kinds: we may (1) replace the ontology with one formulated in a tractableontology language such as ELI or certain TGDs .…

## Teaching Design by Contract using Snap

Snap! is a visual programming language aimed at high school students . We provide support both for static and dynamic verification of Snap! programs . Special attention is given to the error messaging, to make this as intuitive as possible .…

## ROBIN A Robust Optical Binary Neural Network Accelerator

Domain specific neural network accelerators have garnered attention because of their improved energy efficiency and inference performance compared to CPUs and GPUs . However, mapping sophisticated neural network models on theseaccelerators still entails significant energy and memory consumption, alongwith high inference time overhead .…

## Measuring scientific output of researchers by t index and Data Envelopment Analysis

There is a growing need for ranking universities, departments, research groups, and individual scholars . The t-index takes into account the number of citations, number of coauthors on every published paper, and career duration . We also use in this paper the data Envelopment Analysis (DEA) to measure the scientific merits of the researchers within the observed group of researchers .…

## Quantum Radon Transform and Its Application

A new kind ofperiodic discrete Radon transform (PDRT) called quantum Radon transforms (QRT) is proposed . The QRT has a quantum implementation that is exponentially faster than the classical Radon Transform . The simulation results show that QRTpreserves the good denoising capability as in the classical PDRT .…

## Separating LREC from LFP

LREC= is an extension of first-order logic with a logarithmic recursion operator . It was introduced by Grohe et al. and shown to capture complexityclass L over trees and interval graphs . It does not capture L in general as it is contained in FPC – fixed-point logic with counting .…

## Strong recovery of geometric planted matchings

We study the problem of efficiently recovering the matching between anunlabelled collection of $n$ points in $\mathbb{R}^d$ and a small randomperturbation of those points . In this setting, the maximum likelihood estimator can be found in polynomial time as the solution of a linear assignmentproblem .…