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arXiv 2020年

作者： Almohammad, Sami Mezal Lángi, Zsolt Naszódi, Márton Inst. of Math. Loránd Eötvös Univ. Budapest Hungary Dept. of Math. Faculty of Comp. Sci. and Math. Univ. of Thi-Qar Thi-Qar Iraq MTA-BME Morphodynamics Research Group Department of Geometry Budapest University of Technology Budapest Hungary Alfréd Rényi Inst. of Math. MTA-ELTE Lendület Com Binatorial Geometry Research Group Dept. of Geometry Lorand Eotvos University Budapest Hungary

Steinitz’s theorem states that a graph G is the edge-graph of a 3-dimensional convex polyhedron if and only if, G is simple, plane and 3-connected. We prove an analogue of this theorem for ball polyhedra, that is, for intersections of finitely many unit balls in R3MSC Codes 52B10, 52A30, 52B05 Copyright © 2020, The Authors. All rights reserved.

关键词： Geometry

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On the comp.exity of query answering under access limitations: A comp.tational formalism 12

On the complexity of query answering under access limitation...

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12th Alberto Mendelzon International Workshop on Foundations of Data Management, AMW 2018

作者： Caĺi, Andrea Ugarte, Martin 1Dept of Comp. Sci. and Inf. Syst. Birkbeck Univ. of London United Kingdom Comp. and Decision Eng. Dept. Universite Libre de Bruxelles Belgium Oxford-Man Inst. of Quantitative Finance University of Oxford United Kingdom

The Deep Web is the large corpus of data accessible on the Web through forms and presented in dynamically-generated pages, but not indexable as static pages, and therefore invisible to search engines. Deep Web data are usually modelled as relations with so-called access limitations, that is, they can be queried only by selecting certain at-tributes. In this paper we give some fundamental comp.exity results on the problem of processing conjunctive (select-project-join) queries on re-lational data with access limitations. © 2018 CEUR-WS. All rights reserved.

关键词： Search engines

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Processing SPARQL Queries on Deep Web sources 26

Processing SPARQL Queries on Deep Web sources

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26th Italian Symposium on Advanced Database Systems, SEBD 2018

作者： Calí, Andrea Di Noia, Tommaso Lynch, Thomas W. Ragone, Azzurra Dept of Comp. Sci. and Inf. Syst. Birkbeck Univ. of London United Kingdom SisInf Lab Politecnico di Bari Italy Reasoning Technology Ltd United Kingdom Oxford-Man Inst. of Quantitative Finance University of Oxford United Kingdom

The Deep Web is constituted by data accessible through dynamic Web pages requested through a Web interface. While Deep Web data sources have been usually modelled as relational in the literature, in many cases it is useful to export Deep Web data as Linked Data sets. In this context, processing queries poses some algorithmic challenges due to the inherent limitations of Deep Web sources which, requiring some inputs to be queried, function as services. In this paper we present a framework and a system to export Deep Web data as Linked Data sets. Further, we characterise a class of SPARQL queries that are executable directly, in spite of the limitations. © 2018 CEUR-WS. All rights reserved.

关键词： Linked data

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A Simplified and Fast Dehazing Processing Suitable for Embedded Systems

A Simplified and Fast Dehazing Processing Suitable for Embed...

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2018 International Symposium on Intelligent Signal Processing and Communication Systems, ISPACS 2018

作者： Koga, Takanori Yasuda, Ayaka Furukawa, Shota Suetake, Noriaki National Inst. of Tech. Tokuyama Col. Dept. of Comp. Sci. and Electronic Eng. Gakuendai Shunan-shi745-8585 Japan National Inst. of Tech. Kagoshima Col. Dept. Information Engineering 1460-1 Shinkou Hayato-cho Kirishima-shi899-5193 Japan Grad. Sch. of Sci. and Tech. for Innov. Yamaguchi University 1677-1 Yoshida Yamaguchi-shi753-8512 Japan

ISBN: (纸本)9781538657713

The main purpose of image dehazing is to remove undesirable degradation caused by fog and mist to improve the visual quality of an image and provide benefits to postprocessing. In particular, image dehazing systems applied to actual applications such as video surveillance and in-vehicle cameras are required to realize a balanced performance for video streams between dehazing quality and processing speed in low-cost portable embedded devices. To cope with this requirement, in this study, we propose a simple and fast dehazing algorithm which provides high-quality dehazed images and a practical processing speed. Concretely, the proposed method utilizes a simplified transmittance estimation technique with non-linear processing focusing on an optimization of its hardware implementation on a low-cost embedded target board with a graphics processing unit (GPU). Through a series of comp.rative experiments with typical simplified dehazing methods, we verify the effectiveness of the proposed method on dehazing quality and processing speed. © 2018 IEEE.

关键词： Embedded systems

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Understanding and accelerating particle-based variational inference

arXiv

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arXiv 2018年

作者： Liu, Chang Zhuo, Jingwei Cheng, Pengyu Zhang, Ruiyi Zhu, Jun Carin, Lawrence Dept. of Comp. Sci. and Tech. Institute for AI BNRist Center Tsinghua-Fuzhou Inst. for Data Tech. THBI Lab Tsinghua University Beijing100084 China Dept. of Elec. and Comp. Engineering Duke University NC United States

Particle-based variational inference methods (ParVIs) have gained attention in the Bayesian inference literature, for their capacity to yield flexible and accurate approximations. We explore ParVIs from the perspective of Wasserstein gradient flows, and make both theoretical and practical contributions. We unify various finite-particle approximations that existing ParVIs use, and recognize that the approximation is essentially a comp.lsory smoothing treatment, in either of two equivalent forms. This novel understanding reveals the assumptions and relations of existing ParVIs, and also inspires new ParVIs. We propose an acceleration framework and a principled bandwidth-selection method for general ParVIs;these are based on the developed theory and leverage the geometry of theWasserstein space. Experimental results show the improved convergence by the acceleration framework and enhanced sample accuracy by the bandwidth-selection method. Copyright © 2018, The Authors. All rights reserved.

关键词： Inference engines

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Querying the deep web: Back to the foundations 11

Querying the deep web: Back to the foundations

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11th Alberto Mendelzon International Workshop on Foundations of Data Management and the Web, AMW 2017

作者： Calí, Andrea Martinenghi, Davide Razgon, Igor Ugarte, Martín Dept of Comp. Sci. and Inf. Syst. Birkbeck Univ. of London United Kingdom Dip. di Elettr. Informaz. e Bioing Politecnico di Milano Italy Web and Information Tech. Lab Université Libre de Bruxelles Belgium Oxford-Man Inst. of Quantitative Finance University of Oxford United Kingdom

The Deep Web is the large corpus of data accessible on the Web through forms and presented in dynamically-generated pages, but not indexable as static pages, and therefore invisible to search engines. Deep Web data are usually modelled as relations with so-called access limitations, that is, they can be queried only by selecting certain at-Tributes. In this paper we give some fundamental comp.exity results on the problem of processing conjunctive (select-project-join) queries on re- lational data with access limitations.

关键词： Search engines

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Turbulence-induced 2D correlated image distortion

Turbulence-induced 2D correlated image distortion

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IEEE International Conference on comp.tational Photography (ICCP)

作者： Armin Schwartzman Marina Alterman Rotem Zamir Yoav Y. Schechner Div. Biostatistics UC San Diego La Jolla CA USA Dept. Elect. Eng. & Comp. Sci. Northwestern University Evanston IL USA Technion Israel Institute of Technology Haifa Haifa IL Viterbi Faculty of Electrical Eng. Technion - Israel Inst. Technology Haifa Israel

ISBN: (纸本)9781509057467

Due to atmospheric turbulence, light randomly refracts in three dimensions (3D), eventually entering a camera at a perturbed angle. Each viewed object point thus has a distorted projection in a two-dimensional (2D) image. Simulating 3D random refraction for all viewed points via comp.ex simulated 3D random turbulence is comp.tationally expensive. We derive an efficient way to render 2D image distortions, consistent with turbulence. Our approach bypasses 3D numerical calculations altogether We directly create 2D random physics-based distortion vector fields, where correlations are derived in closed form from turbulence theory. The correlations are nontrivial: they depend on the perturbation directions relative to the orientation of all object-pairs, simultaneously. Hence, we develop a theory characterizing and rendering such a distortion field. The theory is turned to a few simple 2D operations, which render images based on camera and atmospheric properties.

关键词： Distortion Two dimensional displays Three-dimensional displays Correlation Rendering (comp.ter graphics) Cameras Refractive index

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Energy-Efficient Scheduling algorithms for Real-Time Data Reporting in 4G LTE Machine-to-Machine Communication Networks

Energy-Efficient Scheduling Algorithms for Real-Time Data Re...

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International Wireless Communications and Mobile comp.ting Conference

作者： Po-Chun Shen Shun-Ren Yang Phone Lin Dept. of Comp. Sci. & Inst. of Commun. Eng. National Tsing Hua University Hsinchu Taiwan Dept. of Comp. Sci. & Info. Eng. National Taiwan University Taipei Taiwan

ISBN: (纸本)9781509003051

Machine-to-machine (M2M) communications protocols, e.g., Machine Type Communications (MTC) in 3GPP LTE, support a variety of Machine to Machine (M2M) applications, which requires real-time data reporting. Many uplink scheduling algorithms are primarily designed for human-to-human applications rather than for M2M applications. These scheduling algorithms typically are based on the fact that the machines in MTC are battery-powered and aim to reduce the energy consumption. We notice that the current literature considers either the problem of sleep-time maximization or transmission power minimization, but not both. In this paper, we systematically consider all energy-consumption factors of M2M real-time reporting. Using MTC in LTE as an example for M2M communications, in this paper, we propose two energy-efficient scheduling algorithms to minimize the total energy consumption of machines for M2M communications. The two proposed algorithms utilize the distance between a machine and the serving eNB (i.e., base station in LTE). Our performance study shows that our algorithms have performance enhancement in terms of energy consumption comp.red to other algorithms in the previous works. Furthermore, our algorithms can maintain high scheduling success ratio and fairness.

关键词： Energy efficiency LTE Machine-to-machine (M2M) Real-time data reporting

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Refactoring Cost Estimation (RCE) Model for Object Oriented System

Refactoring Cost Estimation (RCE) Model for Object Oriented ...

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IEEE International Advance comp.ting Conference

作者： Ankit B. Desai Jekishan K. Parmar Inst. of Eng. & Technol. Ahmedabad Univ. Ahmedabad India Educ. Campus Dept. of Comp. Sci. & Eng. BITS Vadodara India

ISBN: (纸本)9781467382878

Successful software systems must be developed to evolve or die. Although object-oriented software systems are to be built to last over the time but they will degrade as much as any legacy software system. As a consequence, one may identify various reengineering patterns which capture best practice in reverse and reengineering object-oriented legacy systems. Software reengineering basically focuses on re-implementing older systems to improve or make it more maintainable. Refactoring is on kind of re-engineering with-in an Object-Oriented context. In this paper, with the given object-oriented refactoring opportunities, the cost of refactoring is resembled using RCE. The opportunities are class misuse, violation of the principle of encapsulation, lack of use of inheritance concept, misuse of inheritance, misplaced polymorphism.

关键词： Refactoring RCE Model Refactoring Cost

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A New and Cheap Methodology to Study Tridimensionally Pitting Corrosion in Stainless Steel

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ECS Meeting Abstracts 2018年第14期MA2018-01卷

作者： Dyovani Coelho Oscar Cuadros Linares Aloadir Oliveira Marcos Andrade Emerson Rios Alexsandro Mendes Zimer Lucia Helena Mascaro Joao do Espirito Santo Batista Neto Odemir Martinez Bruno Ernesto Chaves Pereira Dept. Chemistry Federal University of Sao Carlos Inst. Math. Comp. Sci. Univ of Sao Paulo S Carlos Brazil. Chem. Dept. - Federal Univ. Sao Carlos Sao Carlos Brazil Chem Dept - Federal University Sao Carlos S Carlos Brazil Chem. Dept Federal Univ. Sao Carlos S. Carlos Brazil Chem. Dept Federal Univ. of Sao Carlos S. Carlos Brazil Federal University of São Carlos Int. Math Comp Sci. S Paulo Univ. S Carlos Brazil Phys Inst S Carlos S Paulo Univ Sao Carlos Brazil Federal University of Sao Carlos

According to NACE International, the global cost generated by corrosion is about US$ 2.5 trillion and up to 35% could be saved by using corrosion control practices[1]. However, the correct choice of the method to control the corrosion it is tied to the knowledge of how the process happens. In this aspect, the pitting corrosion on stainless surfaces is extremely worrying. This kind of corrosion is a localized form which cavities are produced in the materials, but it is more difficult to detect, predict and avoid or minimize. Here is proposed a new and cheap methodology to study the tridimensional format of the pitting corrosion using reconstruction of segmented images. The pitting were produced by polarization of stainless steel AISI 304 at 0.46 V (vs Ag/AgCl/KCl satured) into 0.1 mol L- 1 HCl during 10 minutes at 25 °C. Afterwards, the samples were cut, washed with pure water, dried and immersed into resin keeping the plane of surface in a perpendicular direction to the base of resin block. Next, the resin block was polished using sandpaper (mesh 2000) and alumina slurry (1 μm). Every 8 μm of scraping one optical microscopy image of the surface-bulk of the sample was taken. This procedure allowed a side view of the pitting detailing its shape and extension. Finally, the segmented images were reconstructed in a tridimensional one, which shows in detail the shape and extension of each pitting in the surface of stainless steel. Now, the distribution of pitting and its shape variation could be related to the other physical and chemical signals monitored during the pitting formation, as current intensity or chemical comp.sition. This methodology, although destructive, is easily applicable and allows to evaluate in an inexpensive and reproducible way the pitting formation.

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