59 research outputs found

    LIPIcs, Volume 261, ICALP 2023, Complete Volume

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    LIPIcs, Volume 261, ICALP 2023, Complete Volum

    LIPIcs, Volume 274, ESA 2023, Complete Volume

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    LIPIcs, Volume 274, ESA 2023, Complete Volum

    Closing the loop: the integration of long-term ambient vibration monitoring in structural engineering design

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    his study investigated the integration of long-term monitoring into the structural engineering design process to improve the design and operation of civil structures. A survey of civil and structural engineering professionals, conducted as part of this research, identified the cost and complexity of in-situ monitoring as key barriers to their implementation in practice. Therefore, the research focused on the use of ambient vibration monitoring as it is offers a low cost and unobtrusive method for instrumenting new and existing structures. The research was structured around the stages of analysing ambient vibration data using operational modal analysis (OMA), defined in this study as: i) pre-selection of analysis parameters, ii) pre-processing of the data, iii) estimation of the modal parameters, iv) identification of modes of vibration within the modal estimates, and v) using modal parameter estimates as a basis for understanding and quantifying in-service structural behaviour. A method was developed for automating the selecting of the model order, the number of modes of vibrations assumed to be identifiable within the measured dynamic response. This method allowed the modal estimates from different structures, monitoring periods or analysis parameters to be compared, and removed part of the subjectivity identified within current OMA methods. Pre-processing of ambient acceleration responses through filtering was identified as a source of bias within OMA modal estimates. It was shown that this biasing was a result of filtering artefacts within the processed data. Two methods were proposed for removing or reducing the bias of modal estimates induced by filtering artefacts, based on exclusion of sections of the response corrupted by the artefacts or fitting of the artefacts as part of the modal analysis. A new OMA technique, the short-time random decrement technique (ST-RDT) was developed on the basis of the survey of industry perceptions of long-term monitoring and limitations of existing structural monitoring techniques identified within the literature. Key advantages of the ST-RDT are that it allows the uncertainty of modal estimates and any changes in modal behaviour to be quantified through subsampling theory. The ST-RDT has been extensively validated with numerical, experimental and real-world case studies including multi-storey timber buildings and the world's first 3D printed steel bridge. Modal estimates produced using the ST-RDT were used as a basis for developing an automated method of identifying modes of vibration using a probabilistic mixture model. Identification of modes of vibration within OMA estimates was previously a specialized skill. The procedure accounts for the inherent noise associated with ambient vibration monitoring and allows the uncertainty within the modal estimates associated with each mode of vibration to be quantified. Methods of identifying, isolating and quantifying weak non-linear modal behaviour, changes in dynamic behaviour associated with changes in the distributions of mass or stiffness within a structure have been developed based on the fundamental equations of structural dynamics. These methods allow changes in dynamic behaviour associated with thermally-induced changes in stiffness or changes in static loading to be incorporated within the automated identification of modes of vibration. These methods also allow ambient vibration monitoring to be used for estimating structural parameters usually measured by more complex, expensive or delicate sensors. Examples of this include estimating the change in elastic modulus of simple structures with temperature or estimating the location and magnitude of static loads applied to a structure in-service. The methods developed in this study are applicable to a wide range of structural monitoring technologies, are accessible to non-specialist audiences and may be adapted for the monitoring of any civil structure

    Foundations of Software Science and Computation Structures

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    This open access book constitutes the proceedings of the 25th International Conference on Foundations of Software Science and Computational Structures, FOSSACS 2022, which was held during April 4-6, 2022, in Munich, Germany, as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2022. The 23 regular papers presented in this volume were carefully reviewed and selected from 77 submissions. They deal with research on theories and methods to support the analysis, integration, synthesis, transformation, and verification of programs and software systems

    Law and Policy for the Quantum Age

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    Law and Policy for the Quantum Age is for readers interested in the political and business strategies underlying quantum sensing, computing, and communication. This work explains how these quantum technologies work, future national defense and legal landscapes for nations interested in strategic advantage, and paths to profit for companies

    Hamiltonian Complexity in Many-Body Quantum Physics

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    The development of quantum computers has promised to greatly improve our understanding of quantum many-body physics. However, many physical systems display complex and unpredictable behaviour which is not amenable to analytic or even computational solutions. This thesis aims to further our understanding of what properties of physical systems a quantum computer is capable of determining, and simultaneously explore the behaviour of exotic quantum many-body systems. First, we analyse the task of determining the phase diagram of a quantum material, and thereby charting its properties as a function of some externally controlled parameter. In the general case we find that determining the phase diagram to be uncomputable, and in special cases show it is P^{QMA_{EXP}}-complete. Beyond this, we examine how a common method for determining quantum phase transitions --- the Renormalisation Group (RG) --- fails when applied to a set of Hamiltonians with uncomputable properties. We show that for such Hamiltonians (a) there is a well-defined RG procedure, but this procedure must fail to predict the uncomputable properties (b) this failure of the RG procedure demonstrates previously unseen and novel behaviour. We also formalise in terms of a promise problem, the question of computing the ground state energy per particle of a model in the limit of an infinitely large system, and show that approximating this quantity is likely intractable. In doing this we develop a new kind of complexity question concerned with determining the precision to which a single number can be determined. Finally we consider the problem of measuring local observables in the low energy subspace of systems --- an important problem for experimentalists and theorists alike. We prove that if a certain kind of construction exists for a class of Hamiltonians, , the results about hardness of determining the ground state energy directly implies hardness results for measuring observables at low energies

    Mobile Robots

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    The objective of this book is to cover advances of mobile robotics and related technologies applied for multi robot systems' design and development. Design of control system is a complex issue, requiring the application of information technologies to link the robots into a single network. Human robot interface becomes a demanding task, especially when we try to use sophisticated methods for brain signal processing. Generated electrophysiological signals can be used to command different devices, such as cars, wheelchair or even video games. A number of developments in navigation and path planning, including parallel programming, can be observed. Cooperative path planning, formation control of multi robotic agents, communication and distance measurement between agents are shown. Training of the mobile robot operators is very difficult task also because of several factors related to different task execution. The presented improvement is related to environment model generation based on autonomous mobile robot observations

    The Significance of Evidence-based Reasoning in Mathematics, Mathematics Education, Philosophy, and the Natural Sciences

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    In this multi-disciplinary investigation we show how an evidence-based perspective of quantification---in terms of algorithmic verifiability and algorithmic computability---admits evidence-based definitions of well-definedness and effective computability, which yield two unarguably constructive interpretations of the first-order Peano Arithmetic PA---over the structure N of the natural numbers---that are complementary, not contradictory. The first yields the weak, standard, interpretation of PA over N, which is well-defined with respect to assignments of algorithmically verifiable Tarskian truth values to the formulas of PA under the interpretation. The second yields a strong, finitary, interpretation of PA over N, which is well-defined with respect to assignments of algorithmically computable Tarskian truth values to the formulas of PA under the interpretation. We situate our investigation within a broad analysis of quantification vis a vis: * Hilbert's epsilon-calculus * Goedel's omega-consistency * The Law of the Excluded Middle * Hilbert's omega-Rule * An Algorithmic omega-Rule * Gentzen's Rule of Infinite Induction * Rosser's Rule C * Markov's Principle * The Church-Turing Thesis * Aristotle's particularisation * Wittgenstein's perspective of constructive mathematics * An evidence-based perspective of quantification. By showing how these are formally inter-related, we highlight the fragility of both the persisting, theistic, classical/Platonic interpretation of quantification grounded in Hilbert's epsilon-calculus; and the persisting, atheistic, constructive/Intuitionistic interpretation of quantification rooted in Brouwer's belief that the Law of the Excluded Middle is non-finitary. We then consider some consequences for mathematics, mathematics education, philosophy, and the natural sciences, of an agnostic, evidence-based, finitary interpretation of quantification that challenges classical paradigms in all these disciplines

    Western Oregon University 2019-2020 Course Catalog

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    https://digitalcommons.wou.edu/coursecatalogs/1022/thumbnail.jp

    29th International Symposium on Algorithms and Computation: ISAAC 2018, December 16-19, 2018, Jiaoxi, Yilan, Taiwan

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