Linear Size Universal Discretization of Geometric Center Based Problems in Fixed Dimensions

Many geometric optimization problems can be reduced to finding points inspace (centers) minimizing an objective function which continuously depends on the distances from the centers to given input points . Examples are $k-Means, $k$-Median/Center, Continuous Facility Location, $m$-Variance, etc. The existence of such a linear-size set of candidates is also shown for any metric space offixed doubling dimension .…

Temporal Induced Self Play for Stochastic Bayesian Games

Temporal-Induced Self-Play (TISP) is a novel reinforcement learning-basedframework to find strategies with decent performances from any decision point onward . TISP uses belief-space representation, backward induction, policylearning, and non-parametric approximation . The results show that TisP-PG is more scalable than existing mathematicalprogramming-based methods and significantly outperforms other learning–basedmethods .…

Full waveform inversion using triangular waveform adapted meshes

In this article, continuous Galerkin finite elements are applied to performfull waveform inversion (FWI) for seismic velocity model building . Atime-domain FWI approach is detailed that uses meshes composed of variablysized triangular elements to discretize the domain . To resolve both the forwardand adjoint-state equations, and to calculate a mesh-independent gradient associated with the FWI process, a fully-explicit, variable higher-order (up todegree $k=5$ in $2$D) mass lumping method is used .…

Making RDBMSs Efficient on Graph Workloads Through Predefined Joins

Joins in native graph database management systems (GDBMSs) are predefined to the system as edges, which are indexed in adjacency list indices and serve aspointers . This contrasts with and can be more performant than value-based joins in RDBMS . Wepropose a purely relational approach to integrate predefined joins in columnar databases that uses row IDs (RIDs) of tuples as pointers .…

Art Gallery Plus Single Specular reflection

Given a simple polygon in the Art Gallery problem, the goal is to find the minimum number of guards needed to cover the entire $cal P$ . This paper studies a variant of the problem in which theboundaries of the polygon are replaced by single specular-reflection edges .…

Consistent Simplification of Polyline Tree Bundles

The Polyline Bundle Simplification (PBS) problem is a generalization of the classical polyline simplification problem . Given a set of polylines, which mayshare line segments and points, PBS asks for the smallest consistentsimplification of these polylines with respect to a given distance threshold .…

Full waveform inversion using triangular waveform adapted meshes

In this article, continuous Galerkin finite elements are applied to performfull waveform inversion (FWI) for seismic velocity model building . Atime-domain FWI approach is detailed that uses meshes composed of variablysized triangular elements to discretize the domain . To resolve both the forwardand adjoint-state equations, and to calculate a mesh-independent gradient associated with the FWI process, a fully-explicit, variable higher-order (up todegree $k=5$ in $2$D) mass lumping method is used .…

Context aware Telco Outdoor Localization

Telco localization is a technique employed by Telco operators to localize outdoor mobile devices by using measurement report (MR) data . RLoc consists of three main components: amachine-learning-based localization algorithm, a detection algorithm to find outflawed samples, and a repair algorithm to replace outlier localization results by better ones (ideally ground truth positions) For example, RLoc on a large 4G MR data setcan achieve 32.2 meters of median errors, around 17.4% better than state-of-the-art RLoc can greatlyimprove Telco location accuracy, says the authors of a paper on the subject of a new form of machine-learning algorithm that takes into account spatio-temporal locality of MR locations and exploit trajectory context to detect and repair flawed positions .…

Fast Evaluation of Smooth Distance Constraints on Co Dimensional Geometry

We present a new method for computing a smooth minimum distance function for point clouds, edge meshes, trianglemeshes and combinations of all three . We derive blending weights and amodified Barnes-Hut acceleration approach that ensure our method isconservative (points outside the zero isosurface are guaranteed to be outsidethe surface) Our method is accurate and efficient to evaluate for all the above data types .…

Linear Size Universal Discretization of Geometric Center Based Problems in Fixed Dimensions

Many geometric optimization problems can be reduced to finding points inspace (centers) minimizing an objective function which continuously depends on the distances from the centers to given input points . Examples are $k-Means, $k$-Median/Center, Continuous Facility Location, $m$-Variance, etc. The existence of such a linear-size set of candidates is also shown for any metric space offixed doubling dimension .…

Quasi upward Planar Drawings with Minimum Curve Complexity

This paper studies the problem of computing quasi-upward planar drawings of bimodal plane digraphs with minimum curve complexity . We prove that every bimmodalplane digraph admits a quasi-upsar drawing with curve complexity two, which is worst-case optimal . We also show that the problem can be modeled as a min-costflow problem on a unit-capacity planar flow network .…

VizLinter A Linter and Fixer Framework for Data Visualization

VizLinter aims to help users detect flaws and rectify already-built butdefective visualizations . The framework consists of two components, (1) avisualization linter, (2) a visualization fixer, whichautomatically corrects the detected violations according to the linter . We implement the framework into an online editor prototype based on Vega-Litespecifications.…

Outdoor Position Recovery from HeterogeneousTelco Cellular Data

Recent years have witnessed unprecedented amounts of data generated by bytelecommunication (Telco) cellular networks . PRNet+ is a multi-tasklearning-based deep neural network (DNN) framework, namely PRNet+. It incorporates outdoor position recovery and transportation mode detection . The existing solutions cannot handle these heterogeneous mobility patterns due to mixed transportation modes of the underlying mobile devices and uneven distribution of the positions associated with MR samples .…

The complexity of testing all properties of planar graphs and the role of isomorphism

Newman-Sohler (SICOMP2013) asserts that all properties of planar graphs (more generally hyperfinite)are testable with query complexity only depending on $poly(\varepsilon$) The upper bound is a straightforward adapation of an analysis that tracks dependencies on the variables on a graph . The natural property of testing isomorphism to a fixed graph requires $\exp(O(O)\exp) O(O(‘O))’)’satisfactory’ is the hardest property to test .…

The staircase property How hierarchical structure can guide deep learning

This paper identifies a structural property of data distributions that enables deep neural networks to learn hierarchically . The “staircase”property for functions over the Boolean hypercube posits that high-orderFourier coefficients are reachable from lower-order Fourier coefficients alongincreasing chains . We prove that functions satisfying this property can belearned in polynomial time using layerwise stochastic coordinate descent on regular neural networks .…

An Efficient ADER DG Local Time Stepping Scheme for 3D HPC Simulation of Seismic Waves in Poroelastic Media

Many applications from geosciences require simulations of seismic waves inporous media . We present a novel realisation of the discontinuous Galerkin schemewith Arbitrary DERivative time stepping (ADER-DG) that copes with stiff sourceterms . The block-wiseback-substitution is mapped to a sequence of small matrix-matrix multiplications, for which code generators are available to generate highlyoptimised code .…

Randomized C C dynamic memory allocator

Randomization is a key feature intended to protect applications from “use-after-free” or similar attacks . At the same time, the state in the algorithm consists only of one pointer, so it does not consume extra memory foritself . However, our algorithm is not a universal solution.…

Quasi upward Planar Drawings with Minimum Curve Complexity

This paper studies the problem of computing quasi-upward planar drawings of bimodal plane digraphs with minimum curve complexity . We prove that every bimmodalplane digraph admits a quasi-upsar drawing with curve complexity two, which is worst-case optimal . We also show that the problem can be modeled as a min-costflow problem on a unit-capacity planar flow network .…

Consistent Simplification of Polyline Tree Bundles

The Polyline Bundle Simplification (PBS) problem is a generalization of the classical polyline simplification problem . Given a set of polylines, which mayshare line segments and points, PBS asks for the smallest consistentsimplification of these polylines with respect to a given distance threshold .…

The Mays and Musts of Concurrent Strategies

Concurrent strategies based on event structures are examined from theviewpoint of ‘may’ and ‘must’ testing in traditional process calculi. In theirpure form concurrent strategies fail to expose the deadlocks and divergencesthat can arise in their composition . This motivates an extension of thebicategories of concurrent strategies to treat the ‘may and must’ behaviour of strategies under testing .…

Language Transformations in the Classroom

Language transformations are algorithms that take a language specification in input, and return the language specification modified . They are useful for automatically adding features such as subtyping to programming languages, and for automatically deriving abstract machines . In this paper, we set forth the thesis that teaching programming languagesfeatures with the help of language transformations can be beneficial for students to help them deepen their understanding of the features being taught .…

Access to Digital Platforms Can Mobile Network Coverage Reports be Relied Upon Observations from Rural Zambia and Zimbabwe

Access to digital platforms in Africa is mostly through ‘mobile’ networks . Paper shines a critical light on the meaning of terms like access and the 4th industrial revolution from an African context . Itargues for the need to invest in contextual research and development, also togain a comprehensive understanding of how to access digital platforms .…

The Moderating Effect of Gender on Adopting Digital Government Innovations in Ethiopia

Digital government innovation is being recognised as a solution to many problems faced by governments in providing services to their citizens . It is especially important for low-income countries where there are resource constraints . Research was aimed at exploring the moderating effect of gender on the adoption of a digital government innovation in Ethiopia based on the UTAUT model (n=270) and using structural equation modeling (SEM) The results reveal that gender only moderates the relationship between facilitatingconditions and usage behavior of government employees to adopt the digitalgovernment innovation which is inconsistent with other findings .…

Artificial Intelligence in the Global South AI4D Potential and Risks

Artificial intelligence is becoming more widely available in all parts of the world . This paper examines the key issues and questions arising in the emergingsub-field of AI for global development (AI4D) We propose that although there are many risks associated with the use of AI, the potential benefits are enough to warrant detailed research and investigation of the most appropriate and effective ways to design, develop, implement, and use such technologies in the Global South .…

Medical Graphs in Patient Information Systems in Primary Care

Graphs are very effective tools in visualizing information and are used in many fields including the medical field . In most developing countries primarycare, graphs are used to monitor child growth . These measures are therefore often displayed using line graphs, basing it on three indicators (stunting,underweight and wasting) based on the WHO 2006 Child Growth Standard .…