Variations on the Post Correspondence Problem for free groups

The Post Correspondence Problem is a classical decision problem about equalisers of free monoid homomorphisms . We prove connections between severalvariations of this classical problem, but in the setting of free groups and free group homomorphism . Among other results, and working under certaininjectivity assumptions, we prove that computing the rank of the equaliser of apair of free grouphomomorphisms can be applied to computing a basis of this equaliser .…

Sparse Coding Frontend for Robust Neural Networks

Deep Neural Networks are known to be vulnerable to small, adversariallycrafted, perturbations . The current most effective defense methods against these adversarial attacks are variants of adversarial training . In this paper, we introduce a radically different defense trained only on clean images .…

ON OFF Privacy Against Correlation Over Time

We consider the problem of ON-OFF privacy in which a user is interested inthe latest message generated by one of n sources available at a server . The challenge of allowing the privacy tobe toggled between ON and OFF is that the user’s online behavior is correlated over time .…

Extractive Multi Product Line Engineering

Cloning is a general approach to create new functionality within variants as well as new system variants . It is a fast, flexible, intuitive, and economical approach to evolve systems in the short run . However, clones within a variant are usually not considered in the process, but are also a cause for unsustainable software .…

Equivariant geometric learning for digital rock physics estimating formation factor and effective permeability tensors from Morse graph

We present a SE(3)-equivariant graph neural network (GNN) approach that predicts the formation factor and effective permeability from micro-CT images . FFT solvers are established to compute both the formationfactor and effectiveness permeability, while the topology and geometry of the porespace are represented by a persistence-based Morse graph .…

On Analyzing Churn Prediction in Mobile Games

In mobile games industry, the churn rate is often pronounced due to the high competition and cost in customer acquisition . This needs churn prediction, predicting users who will be churning within a given time period . Accuratechurn prediction can enable the businesses to devise and engage strategicremediations to maintain a low churn rate.…

Speaking of Trust Speech as a Measure of Trust

We propose to use speech cues (on what, when and how the user talks) as an objective real-time measure of trust . This could be implemented in the robot to calibrate towards appropriate trust . However, we would like to open the discussion on how to deal with the ethical implications of this trust measure .…

A Scalable Algorithm for Decentralized Actor Termination Detection

Automatic garbage collection (GC) prevents certain kinds of bugs and reducesprogramming overhead . GC techniques for sequential programs are based onreachability analysis . However, testing reachability from a root set is inadequate for determining whether an actor is garbage . We present a low-overhead reference listing technique (called DRL) fortermination detection in actor systems .…

Noether The More Things Change the More Stay the Same

Symmetries have proven to be important ingredients in the analysis of neuralnetworks . We undertake a systematic study of the role that symmetry plays . Symmetry alone does not specify the optimization path, but the more symmetries are contained in the model the more restrictions are imposed on the path .…

MIPROT A Medical Image Processing Toolbox for MATLAB

This paper presents a Matlab toolbox to perform basic image processing and visualization tasks, particularly designed for medical image processing . The toolbox is entirely written in native Matlab code, but is fast and flexible . Main use cases for the toolbox are illustrated here, including image input/output, pre-processing, filtering, image registration and visualisation .…

Towards Collaborative Mobile Crowdsourcing

Collaborative Mobile Crowdsourcing (CMC) enables task requesters tohire groups of IoT devices’ users that must communicate with each other and coordinate their operational activities in order to accomplish complex tasks . The vast majority of previous studies focused on non-cooperative MC schemes in Internet of Things (IoT) systems .…

A High Performance Persistent Memory Key Value Store with Near Memory Compute

MCAS (Memory Centric Active Storage) is a persistent memory tier for durable data storage . It is designed from the ground-up toprovide a key-value capability with low-latency guarantees and data durability . To reduce data movement and makefurther gains in performance, we provide support for user-defined “push-down”operations (known as Active Data Objects) that can execute directly and safely on the value-memory associated with one or more keys .…

A coevolutionairy approach to deep multi agent reinforcement learning

Recent research shows that Deep Neuroevolution (DNE) is alsocapable of evolving multi-million-parameter DNN’s . So far, DNE has only been applied to complex single-agent problems . In this paper, we describe and validate a new approachbased on Coevolution . To validate our approach, we benchmark two DeepCoevolutionary Algorithms on a range of multi-agent Atari games and compare our results against the results of Ape-X DQN .…

MIMO OFDM Based Massive Connectivity With Frequency Selectivity Compensation

In this paper, we study how to efficiently and reliably detect active devicesand estimate their channels in a multiple- input multiple-input multiple-output (MIMO)orthogonal frequency-division multiplexing (OFDM) system . We propose a block-wise linear channel model and an efficient turbo message passing (Turbo-MP) algorithm to resolve the Bayesian inference problem with near-linearcomplexity .…

Polar Precoding A Unitary Finite Feedback Transmit Precoder for Polar Coded MIMO Systems

We propose a unitary precoding scheme to improve polar-coded MIMO systems . The proposed polar-precoding scheme relies on the polarization criterion . Our simulation results show that the proposal outperforms the state-of-the-art DFT pre-code scheme . In contrast to the traditional design of MIMo precoding criteria, we design a matrix for maximizing polarization among data streams without degrading the capacity .…

What We Measure in Mixed Reality Experiments

There are many potential measures that one might use when evaluating mixed reality experiences . In this position paper I will argue that there arevarious stances to take for evaluation, depending on the framing of the work . I will sketch out some directions for developing more robust measures that can help the field move forward.…

Epigenetic evolution of deep convolutional models

The genome encoding and the crossover operator are extended to make them applicable to layered networks . The proposed layout enables the size and shape of individual kernels within a convolutional layer to be evolved with acorresponding new mutation operator. The proposed framework employs a hybridoptimisation strategy involving structural changes through epigenetic evolutionand weight update through backpropagation in a population-based setting .…

Loss of structural balance in stock markets

We establish theoretical relationship between the level of balance in a network and stockpredictability . We use rank correlations as distance functions to establish theinterconnectivity between stock returns . We find a clear balance-unbalance transition for six of the nine countries, following the August 2011 Black Monday in the US, when the Economic PolicyUncertainty index for this country reached its highest monthly level before theCOVID-19 crisis .…

LocalViT Bringing Locality to Vision Transformers

We study how to introduce locality mechanisms into vision transformers . Locally-enhanced transformers outperform the baselines DeiT-T and PVT-t by 2.6\% and 3.1\% with a negligible increase in the number of parameters and effort . The same mechanism was used to apply to 4 visiontransformers, which shows the generalization of the locality concept .…

Personalized Bundle Recommendation in Online Games

The bundle recommendation model has been deployed in production formore than one year in a popular online game developed by Netease Games . The model yields more than 60\% improvement on conversion rate of Bundles, and a relative improvement of more than 15\% on gross merchandisevolume .…

Unsuitability of NOTEARS for Causal Graph Discovery

Causal Discovery methods aim to identify a DAG structure that represents causal relationships from observational data . We stress that it is important to test such methods for robustness in practical settings . We conclude that NOTEARS is not suitable for identifying truly causalrelationships from the data .…

Can Author Collaboration Reveal Impact The Case of h index

A more intense collaboration can result into increased productivity which can potentially have an impact on the author’s future$h$-index . The proposed method outperforms standard machinelearning techniques based on simple graph metrics along with noderepresentations learned from the textual content of the authors’ papers .…

A Coq Formalization of Lebesgue Integration of Nonnegative Functions

Integration, just as much as differentiation, is a fundamental calculus tool that is widely used in many scientific domains . Formalizing the mathematicalconcept of integration and the associated results in a formal proof assistant helps providing the highest confidence on the correction of numerical programs involving the use of integration, directly or indirectly .…

Entropoid Based Cryptography

Entropoid Diffie-Hellman problem is hard in Sylow $q$-subquasigroups . We post a conjecture that DEDHP is hard for Sylow- $q$.-subaquasig Groups . The entropoid based cryptographic primitives are supposed to be resistant to quantum algorithms . We give a proof-of-concept implementation in SageMath 9.2 for all proposed algorithms and schemes in an appendix .…

Pure Exploration with Structured Preference Feedback

We consider the problem of pure exploration with subset-wise preferencefeedback, which contains $N$ arms with features . The learner is allowed to query subsets of size $K$ and receives feedback in the form of a noisy winner . This setting is relevant in various online decision-makingscenarios involving human feedback such as online retailing, streamingservices, news feed, and online advertising; since it is easier and more reliable for people to choose a preferred item from a subset than to assign alikability score to an item in isolation .…

A Non Negative Matrix Factorization Game

We present a novel game-theoretic formulation of Non-Negative MatrixFactorization (NNMF) The NNFF is a popular data-analysis method with many scientific and engineering applications . The NNFF is shown to havefavorable scaling and parallelization properties .…

WLFC Write Less in Flash based Cache

Flash-based disk cache has been widely used in indurstry in the last decade, such as flashcache (facebook, 2010), bcache (opensource, 2013) These cachesystems typically use commercial SSDs to store and manage cache data . WLFC can significantly reduce the write latency by 70%, increase the write-throughput up to 4.5x, and remove 88.9% unnecessary erase operations at most .…