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Evaluation of Crowdsourcing Wi-Fi Radio Map Creation in a Real Scenario for AAL Applications

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Evaluation of Crowdsourcing Wi-Fi Radio Map Creation in a Re...

International Conference on Intelligent Environments (IE)

作者： Óscar Belmonte-Fernández Arturo Gascó-Compte Emilio Sansano-Sansano Mario Quinde José Ginés Giménez Manuel Juan Carlos Augusto University Jaume I Castellon de la Plana Spain Dpt. Computer Languages and Systems University Jaume I Castellón de la Plana Spain Dpt. Computer Science Middlesex University London UK Dpt. Ingeniería Industrial y de Sistemas Universidad de Piura Piura Perú Middlesex University London UK

ISBN: (数字)9781728129341

ISBN: (纸本)9781728129358

Indoor location at room level plays a key role for providing useful services for Ambient Assisted Living (AAL) applications. Wi-Fi fingerprinting indoor location methods are extensively used due to the widespread availability of Wi-Fi infrastructures. A main drawback of Wi-Fi fingerprinting methods is the temporal cost involved in creating the radio maps. Crowdsourcing strategies have been presented as a way to minimize the cost of radio map creation. In this work, we present an extensive study of the issues involved when using crowdsourcing strategies for that purpose. Results provided by extensive experiments performed in a real scenario by three users during two weeks are presented. The main conclusions are: i) crowdsourcing data improves accuracy location in most studied cases; ii) accuracy of Wi-Fi fingerprinting methods decay along time; iii) device diversity is an important issue even when using the same device model.

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Active flow control for external aerodynamics: from micro air vehicles to a full aircraft in stall

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Journal of Physics: Conference Series 2020年第1期1522卷

作者： Oriol Lehmkuhl Adrián Lozano-Durán Ivette Rodriguez Dpt. of Computer Applications in Science and Engineering Barcelona Supercomputing Center Spain Center for Turbulence Research Stanford University USA Dpt. of Heat Engines Universitat Politecnica de Catalunya Spain

We investigate the aerodynamic performance of active flow control of airfoils and wings using synthetic jets with zero net-mass flow. The study is conducted via wall-resolved and wall-modeled large-eddy simulation using two independent CFD solvers: Alya, a finite-element-based solver; and charLES, a finite-volume-based solver. Our approach is first validated in a NACA4412, for which numerical and experimental results are already available in the literature. The performance of synthetic jets is evaluated for two flow configurations: a SD7003 airfoil at moderate Reynolds number with laminar separation bubble, which is representative of Micro Air Vehicles, and the high-lift configuration of the JAXA Standard Model at realistic Reynolds numbers for landing. In both cases, our predictions indicate that, at high angles of attack, the control successfully eliminates the laminar/turbulent recirculations located downstream the actuator, which increases the aerodynamic performance. Our efforts illustrate the technology-readiness of large-eddy simulation in the design of control strategies for real-world external aerodynamic applications.

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MONITROID: A runtime smart alert malware detection system

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MONITROID: A runtime smart alert malware detection system

2018 International Conference on Smart Systems and Inventive Technology, ICSSIT 2018

作者： Arya, M.A. Philomina, Josna Dpt of Computer Science and Engineering SCMS School of Engineering and Technology Karukutty Angamaly India

ISBN: (纸本)9781538658734

Smart phone has established itself as an inevitable part of one's life. Hence the growth rate of smart phone is expanding every year. In addition to the basic communication services such as voice calls and SMS a smart phone provides a wide variety of useful services such as internet connectivity, gaming, wireless connections with other devices, global positioning systems, digital camera, embedded memory etc. The improved popularity of Android devices and their convenient price attracted the malware developers also, which results in a drastic growth in the development of the Android malware applications (apps), between 2010 and 2018. Researchers have discovered that about four million new malware samples are developed and spread across the android market per year, and it was reported that more than 90% of these new malware samples belongs to any of the existing malware families. Through this paper, we propose a framework named MONITROID which generates a smart alert whenever a malicious app is launched in a user's phone. The alert message informs users about the dangerous impact of currently executing application. The backend server performs a massive malware detection and the identification of the malware family. © 2018 IEEE.

关键词： Android (operating system)

Linear time canonicalization and enumeration of non-Isomorphic 1-Face embeddings 20

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Linear time canonicalization and enumeration of non-Isomorph...

20th Workshop on Algorithm engineering and Experiments, ALENEX 2018

作者： Hellmuth, Marc Knudsen, Anders S. Kotrbík, Michal Merkle, Daniel Nøjgaard, Nikolai Dpt. of Mathematics and Computer Science University of Greifswald Walther-Rathenau-Strasse 47 GreifswaldD-17487 Germany Department of Mathematics and Computer Science University of Southern Denmark Denmark University of Queensland Department of Mathematics QLD4072 Australia Department of Mathematics and Computer Science University of Southern Denmark Denmark Dpt. of Mathematics and Computer Science University of Greifswald Walther-Rathenau-Strasse 47 GreifswaldD-17487 Germany Department of Mathematics and Computer Science University of Southern Denmark Denmark

ISBN: (纸本)9781611975055

Antiparallel strong traces (ASTs) are a type of walks in graphs which use every edge exactly twice. They correspond to 1-face embeddings in orientable surfaces and can be used to design self-assembling protein or DNA strands. Based on a novel canonical form invariant for ASTs, gap vector, we provide a linear-time isomorphism test for ASTs and thus, also for orientable 1-face embeddings of graphs. Using the canonical form, we develop an algorithm for enumerating all pairwise non-isomorphic 1-face embeddings of graphs. We compare our algorithm with an independent implementation of a recent algebraic approach (Baši? et al., MATCH Commun. Math. Comput. Chem. 78 (3), 2017) on large data sets. Our results yield the first large-scale enumeration of non-isomorphic embeddings and investigation of their properties. Copyright © 2018 by SIAM.

关键词： Embeddings

A strong baseline for question relevancy ranking

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arXiv 2018年

作者： González-Garduño, Ana V. Augenstein, Isabelle Søgaard, Anders Dpt. of Computer Science University of Copenhagen

The best systems at the SemEval-16 and SemEval-17 community question answering shared tasks - a task that amounts to question relevancy ranking - involve complex pipelines and manual feature engineering. Despite this, many of these still fail at beating the IR baseline, i.e., the rankings provided by Google's search engine. We present a strong baseline for question relevancy ranking by training a simple multi-task feed forward network on a bag of 14 distance measures for the input question pair. This baseline model, which is fast to train and uses only language-independent features, outperforms the best shared task systems on the task of retrieving relevant previously asked questions. Copyright © 2018, The Authors. All rights reserved.

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A mixture of experts model for predicting persistent weather patterns

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arXiv 2019年

作者： Pérez-Ortiz, M. Gutiérrez, P.A. Tino, P. Casanova-Mateo, C. Salcedo-Sanz, S. Computer Laboratory University of Cambridge United Kingdom Dpt. of Computer Science and Numerical Analysis University of Córdoba Spain School of Computer Science University of Birmingham United Kingdom Department of Civil Engineering: Construction Infrastructure and Transport Universidad Politécnica de Madrid Madrid Spain Department of Signal Processing and Communications University of Alcalá Spain

Weather and atmospheric patterns are often persistent. The simplest weather forecasting method is the so-called persistence model, which assumes that the future state of a system will be similar (or equal) to the present state. Machine learning (ML) models are widely used in different weather forecasting applications, but they need to be compared to the persistence model to analyse whether they provide a competitive solution to the problem at hand. In this paper, we devise a new model for predicting low-visibility in airports using the concepts of mixture of experts. Visibility level is coded as two different ordered categorical variables: cloud height and runway visual height. The underlying system in this application is stagnant approximately in 90% of the cases, and standard ML models fail to improve on the performance of the persistence model. Because of this, instead of trying to simply beat the persistence model using ML, we use this persistence as a baseline and learn an ordinal neural network model that refines its results by focusing on learning weather fluctuations. The results show that the proposal outperforms persistence and other ordinal autoregressive models, especially for longer time horizon predictions and for the runway visual height variable. Copyright © 2019, The Authors. All rights reserved.

关键词： Weather forecasting

TRUTH-PRESERVATION UNDER FUZZY PP-FORMULAS

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arXiv 2019年

作者： Dellunde, Pilar Vidal, Amanda Philosophy Dpt. of the Autonomous University of Barcelona Graduated School of Mathematics & IIIA - CSIC Bellaterra Spain Institute of Computer Science Czech Academy of Sciences Praha Czech Republic

How can non-classical logic contribute to the analysis of complexity in computer science? In this paper, we give a step towards this question, taking a logical model-theoretic approach to the analysis of complexity in fuzzy constraint satisfaction. We study fuzzy positive-primitive sentences, and we present an algebraic characterization of classes axiomatized by this kind of sentences in terms of homomorphisms and direct products. The ultimate goal is to study the expressiveness and reasoning mechanisms of non-classical languages, with respect to constraint satisfaction problems and, in general, in modelling decision scenarios. fuzzy constraint satisfaction, fuzzy logics, model theory. Copyright © 2019, The Authors. All rights reserved.

关键词： Fuzzy logic

Nightmare at test time: How punctuation prevents parsers from generalizing

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arXiv 2018年

作者： Søgaard, Anders De Lhoneux, Miryam Augenstein, Isabee Dpt. of Computer Science University of Copenhagen Dpt. of Linguistics and Philology Uppsala University

Punctuation is a strong indicator of syntactic structure, and parsers trained on text with punctuation often rely heavily on this signal. Punctuation is a diversion, however, since human language processing does not rely on punctuation to the same extent, and in informal texts, we therefore often leave out punctuation. We also use punctuation ungrammaticay for emphatic or creative purposes, or simply by mistake. We show that (a) dependency parsers are sensitive to both absence of punctuation and to alternative uses;(b) neural parsers tend to be more sensitive than vintage parsers;(c) training neural parsers without punctuation outperforms a out-of-the-box parsers across a scenarios where punctuation departs from standard punctuation. Our main experiments are on syntheticay corrupted data to study the effect of punctuation in isolation and avoid potential confounds, but we also show effects on out-of-domain data. Copyright © 2018, The Authors. All rights reserved.

关键词： Computational linguistics

Efficient artifacts filter by density-based clustering in long term 3D whale passive acoustic monitoring with five hydrophones fixed under an Autonomous Surface Vehicle

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Efficient artifacts filter by density-based clustering in lo...

2019 OCEANS - Marseille, OCEANS Marseille 2019

作者： Ferrari, Maxence Poupard, Marion Giraudet, Pascale Marxer, Ricard Prevot, Jean-Marc Soriano, Thierry Glotin, Herve Univ. Toulon Aix Marseille Univ. CNRS LIS DYNI Marseille France LAMFA CNRS Amiens Univ. France U. Toulon AMU CNRS LIS DYNI Marseille France SMIoT Toulon France Biosong SARL France U. Toulon DSIUN Computer Science Dpt. France U. Toulon COSMER France

ISBN: (纸本)9781728114507

Passive underwater acoustics allows for the monitoring of the echolocation clicks of cetaceans. Static hydrophone arrays monitor from a fixed location, however, they cannot track animals over long distances. More flexibility can be achieved by mounting hydrophones on a mobile structure. In this paper, we present the design of a small non-uniform array of five hydrophones mounted directly under the Autonomous Surface Vehicle (ASV) Sphyrna (also called an Autonomous Laboratory Vehicle) built by SeaProven in France. This configuration is made challenging by the 40cm aperture of the hydrophone array, extending only two meters below the surface and above the thermocline, thus presenting various artifacts. The array, fixed under the keel of the drone, is numerically stabilized in yaw and roll using the drone's Motion Processing Unit (MPU). To increase the accuracy of the 3D tracking computed from a four hour recording of a Sperm Whale diving several kilometers away, we propose an efficient joint filtering of the clicks in the Time Delay of Arrival (TDoA) space. We show how the DBSCAN algorithm efficiently removes any outlier detection among the thousands of transients, and yields to coherent high definition 3D tracks. © 2019 IEEE.

关键词： Surveys