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2011 American Control Conference (ACC)

作者： Jeff Borggaard John Burns Lizette Zietsman Interdisciplinary Center for Applied Mathematics and the Department of Mathematics Virginia Technology USA

We discuss four metrics for determining sensor placement in energy efficient building design. These include the norm of the observer gain, the trace of the observer Riccati solution, the distance to the nearest unobservable system, and the linear quadratic Gaussian (LQG) cost from given initial state and state estimates. These metrics have different computational complexity, but all lead to the same optimal sensor location in this study where a single room model is considered.

关键词： Observers Measurement Mathematical model Equations Temperature sensors Computational modeling Control systems

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An efficient long-time integrator for Chandrasekhar equations

An efficient long-time integrator for Chandrasekhar equation...

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IEEE Conference on Decision and Control

作者： Jeff Borggaard Miroslav Stoyanov Department of Mathematics and the Interdisciplinary Center for Applied Mathematics Virginia Technology USA

ISBN: (纸本)9781424431236

A drawback of using Chandrasekhar equations for regulator problems is the need to perform long-time integration of these equations to reach a steady state. Since the equations are stiff, this long-time integration frequently defeats the computational advantages the Chandrasekhar equations have over solving the algebraic Riccati equations. In this paper, we present a strategy for approximating the long-time behavior of the Chandrasekhar equations. Our approach leverages recent developments in building accurate, empirical, reduced-order models for high-order systems. The aim here is to build a reduced-order model for the Chandrasekhar equations that is accurate near the steady state gain. We then assemble a corresponding low-dimensional Riccati equation that can be solved easily. For this study, we use the proper orthogonal decomposition (POD) to generate the reduced-order model. A heuristic for building a suitable input collection for POD is proposed. Numerical experiments using a 2D advection-diffusion-reaction (ADR) equation demonstrate the computational feasibility of our approach.

关键词： Riccati equations Steady-state Reduced order systems Regulators Infinite horizon State feedback Assembly Control systems Distributed parameter systems Distributed control

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Modeling maneuvering targets with GARCH

Modeling maneuvering targets with GARCH

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53rd Israel Annual Conference on Aerospace Sciences 2013

作者： Sigalov, Daniel Oshman, Yaakov Technion-Israel Institute of Technology Haifa 32000 Israel Interdepartmental Program for Applied Mathematics Israel Department of Aerospace Engineering Israel

ISBN: (纸本)9781627481144

We present a novel idea for modeling maneuvering targets using GARCH process noise. GARCH processes seem to capture well the desired properties of evading aerial target maneuvers and, hence, overcome the shortcomings of classical modeling methods. We derive two recursive state estimation algorithms for systems following the new model. The first method is based on a heuristic utilization of the KF mechanization with an ad-hoc technique for process noise estimation. The second algorithm consists of a direct utilization of the EKF approach. Being only an initial attempt, both filters succeed, to some extent, to estimate the target acceleration using position-only measurements.

关键词： Machinery

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Tracking maneuvering targets with a soft bound on the number of maneuvers

Tracking maneuvering targets with a soft bound on the number...

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51st Israel Annual Conference on Aerospace Sciences 2011

作者： Sigalov, Daniel Oshman, Yaakov Technion - Israel Institute of Technology Haifa 32000 Israel Interdepartmental Program for Applied Mathematics Israel Department of Aerospace Engineering Israel

ISBN: (纸本)9781617824012

We revisit the problem of tracking the state of a hybrid system capable of performing a bounded number of mode switches. In a previous paper we have addressed a version of the problem where we have assumed the existence of a deterministic, known hard bound on the number of mode transitions. In addition, it was assumed that the system can possess only two modes, e.g., the maneuvering and non-maneuvering regimes of a tracked target. In the present paper we relax both assumptions: we assume a soft, stochastic bound on the number of mode transitions, and altogether remove the restriction on the number of modes of the system (thus, e.g., the target can have multiple different maneuvering modes, in addition to the non-maneuvering one). While admitting an unlimited number of mode transitions, the soft bound renders that number finite with probability 1. In addition, similarly to the case where the number of transition was deterministically hard-bounded, the existence of the bound renders the mode switching mechanism non-Markov. Thus, the two formulations address similar, though not identical, problems, that cannot be solved by direct application of algorithms devised for hybrid systems having Markov mode switching mechanisms. The novel solution approach adopted herein is based on transforming the non-Markovian mode switching mechanism to an equivalent Markovian one, at the price of augmenting the mode definition, and increasing the dimension of the state space involved. A standard interacting multiple model (IMM) filter is then applied to the transformed (Markovian) problem in a straightforward manner. The performance of the new method is demonstrated via a simulation study comprising three examples, in which the new method is compared with 1) the filter for hard-bounded mode transitions, and 2) a standard IMM filter directly applied to the original problem. The study shows that even when working outside its operating envelope (e.g., when the number of mode switches is har

关键词： Hybrid systems

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Generalization of Advanced Encryption Standard Based on Field of Any Characteristic

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Computers, Materials & Continua 2022年第12期73卷 6121-6138页

作者： Nabilah Abughazalah Majid Khan Noor Munir Ammar SAlanazi Iqtadar Hussain Department of Mathematical Sciences College of SciencePrincess Nourah Bint Abdulrahman UniversityP.O.Box 84428Riyadh 11671Saudi Arabia Department of Applied Mathematics&Statistics Institute of Space TechnologyIslamabadPakistan King Abdulaziz City for Science and Technology RiyadhSaudi Arabia Mathematics Program Department of MathematicsStatistics and PhysicsCollege of Arts and SciencesQatar University2713DohaQatar Statistical Consulting Unit College of Arts and ScienceQatar UniversityDohaQatar

Nowadays most communications are done by utilizing digital transmission *** security of this digital information transmitted through different communication systems is quite *** secrecy of digital data is one of the burning topics of the digitally developed *** exist many traditional algorithms in the literature to provide methods for robust *** most important and recent modern block cipher named the advanced encryption standard(AES)is one of the extensively utilized encryption schemes with binary *** is a succession of four fundamental steps:round key,sub-byte,shift row,and mix *** this work,we will provide an innovative methodology for extending the AES in a Galois fieldwith any characteristic *** four steps in the fundamental process with binary characteristics will be adjusted because of the new *** applying double affine transformations,we have enhanced the number of options in our suggested substitution *** reconstruction of the nonlinear confusion component and encryption structure provides robustness in the generalized *** increase in the keyspace due to the Galois field generalization implies that we have improved additional confusion abilities and broadened the current *** implementation of the proposed structure of AES for image,audio,and video encryption will provide high security for secure communication.

关键词： AES generalized AES binary field ternary function

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Theory of differential approximations of radiative transfer equation 1

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作者： Han, Weimin Eichholz, Joseph A. Sheng, Qiwei Department of Mathematics and Program in Applied Mathematical and Computational Sciences University of Iowa Iowa City IA 52242 United States Department of Mathematics Rose-Hulman Institute of Technology Terre Haute IN 47803 United States

ISBN: (数字)9781461463931

ISBN: (纸本)9781461463924

The radiative transfer equation (RTE) arises in a variety of applications. The equation is challenging to solve numerically for a couple of reasons: high dimensionality, integro-differential form, highly forward-peaked scattering in application. In the literature, various approximations of RTE have been proposed in the literature. In an earlier publication, we explored a family of differential approximations to RTE, to be called RT/DA equations. In this paper, we study the RT/DA equations and investigate numerically the closeness of solutions of the RT/DA equations to that of the RTE. © Springer Science+Business Media New York 2013.

关键词： Radiative transfer

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Recovery of frequency-sparse signals from compressive measurements

Recovery of frequency-sparse signals from compressive measur...

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48th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2010

作者： Duarte, Marco F. Baraniuk, Richard G. Program in Applied and Computational Mathematics Princeton University United States Department of Electrical and Computer Engineering Rice University United States

ISBN: (纸本)9781424482146

Compressive sensing (CS) is a new approach to simultaneous sensing and compression for sparse and compressible signals. While the discrete Fourier transform has been widely used for CS of frequency-sparse signals, it provides optimal sparse representations only for signals with components at integral frequencies. There exist redundant frames that provide compressible representations for frequency-sparse signals, but such frames are highly coherent and severely affect the performance of standard CS recovery. In this paper, we show that by modifying standard CS recovery algorithms to prevent coherent frame elements from being present in the signal estimate, it is possible to bypass the shortcomings introduced by the coherent frame. The resulting algorithm comes with theoretical guarantees and is shown to perform significantly better for frequency-sparse signal recovery than its standard counterparts. The algorithm can also be extended to similar settings that use coherent frames. ©2010 IEEE.

关键词： Compressed sensing

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Scanning protocol influence on relative electron Density-CT number calibrations and radiotherapy dose calculation for a Halcyon Linac

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Radiation Physics and Chemistry 2025年

作者： Thanh Tai, Duong Nhu Tuyen, Pham Duc Tuan, Hoang Hung, Hoang T.P. Kandemir, Recep Omer, Hiba Sulieman, Abdelmoneim Bradley, David Chow, James C.L. Department of Medical Physics Faculty of Medicine Nguyen Tat Thanh University 298-300A Nguyen Tat Thanh Street Ward 13 District 4 Ho Chi Minh City Viet Nam Department of Radiation Oncology University Medical Shing Mark Hospital Dong Nai 810000 Viet Nam Danang Irradiation Facility Research and Development Center for Radiation Technology VINATOM 550000 Da Nang Viet Nam Dokuz Eylül University Institute of Health Sciences Department of Medical Physics Izmir Turkey Dokuz Eylül University Vocational School of Health Services The Program of Radiotherapy Izmir Turkey Department of Radiological Sciences College of Applied Medical Sciences Imam Abdulrahman Bin Faisal University P. O. Box 1982 Dammam34212 Saudi Arabia Department of Radiological Sciences College of Applied Medical Sciences King Saud Bin Abdulaziz University for Health Sciences Al Ahsa Saudi Arabia Imaging Physics Section Research and Innovation Department King Faisal Specialist Hospital & Research Center Riyadh Saudi Arabia Applied Radiation Physics and Technologies Group Sunway University 46150 PJ Malaysia School of Mathematics and Physics University of Surrey GuildfordGU2 7XH United Kingdom Department of Radiation Oncology University of Toronto TorontoONN5T 1P5 Canada Radiation Medicine Program Princess Margaret Cancer Centre University Health Network ONM5G 1X6 Canada

Tissue Relative Electron Density (RED), typically determined via computation of CT-based Hounsfield unit (HU) values, has an accuracy which is affected by the choice of CT scanning parameters. The influence of these on the RED-CT number calibration curves is of importance, not least concerning variations in CT x-ray tube voltage and current. The purpose of this study was to examine the effect of variations in CT x-ray tube voltage and current on the calibration curves of RED - CT number conversion, with the aim of improving the accuracy of dose calculation in radiotherapy treatment planning. An electron density phantom CIRS have been conducted at 200 mAs, for tube voltages of 80, 110, and 130 kVp, corresponding images being calibrated in terms of RED-CT number conversion curves. Subsequent treatment plans have been generated, identified in terms of the applied tube voltages, the 130 kVp plan being designated the reference plan. The remaining plans have been compared to the reference plan via analysis of isodose distribution and dose. The influence of tube voltage were being found to be greatest for high-density substances such as bone in comparison to low-density materials. Conversely, the CT number of a titanium rod has been consistent, regardless of the choice of tube voltage or current. The effect of tube current variation on the calibration curves has been minor at higher tube voltages but more pronounced using lower voltages and current. The presence in the phantom of plugs of high-density materials has resulted in beam hardening artefacts, impacting on the RED values for other plugs. In achieving accurate dose calculation for radiotherapy treatment plans the work underscores the need to account for effects of CT scanning parameters on the RED-CT number conversion curves. Further emphasized is the importance of careful selection of imaging protocols in seeking to minimize beam hardening artefacts and to ensure accurate determination of RED. The study demonstrat

关键词： X ray tubes

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An Efficient Three-Factor Authenticated Key Agreement Technique Using FCM Under HC-IoT Architectures

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Computers, Materials & Continua 2022年第7期72卷 1373-1389页

作者： Chandrashekhar Meshram Agbotiname Lucky Imoize Sajjad Shaukat Jamal Parkash Tambare Adel R.Alharbi Iqtadar Hussain Department of Post Graduate Studies and Research in Mathematics Jayawanti Haksar Government Post-Graduation CollegeCollege of Chhindwara UniversityBetul460001M.P.India Department of Electrical and Electronics Engineering Faculty of EngineeringUniversity of LagosAkokaLagos100213Nigeria Department of Electrical Engineering and Information Technology Institute of Digital CommunicationRuhr University44801BochumGermany Department of Mathematics College of ScienceKing Khalid UniversityAbhaSaudi Arabia Water Resources&Applied Mathematics Research Lab Nagpur440027India College of Computing and Information Technology University of TabukTabuk71491Saudi Arabia Mathematics Program Department of MathematicsStatistics and PhysicsCollege of Arts and SciencesQatar University2713DohaQatar

The Human-Centered Internet of Things(HC-IoT)is fast becoming a hotbed of security and privacy *** users can establish a common session key through a trusted server over an open communication channel using a three-party authenticated key *** of the early authenticated key agreement systems relied on pairing,hashing,or modular exponentiation processes that are computationally intensive and *** order to address this problem,this paper offers a new three-party authenticated key agreement technique based on fractional chaotic *** new scheme uses fractional chaotic maps and supports the dynamic sensing of HC-IoT devices in the network architecture without a password *** projected security scheme utilized a hash function,which works well for the resource-limited HC-IoT *** results show that our new technique is resistant to password guessing attacks since it does not use a ***,our approach provides users with comprehensive privacy protection,ensuring that a user forgery attack causes no ***,our new technique offers better security features than the techniques currently available in the literature.

关键词： Three-party authenticated key agreement anonymity fractional chaotic maps Chebyshev polynomial password table human-centered internet of things(HC-IoT)

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Learning ordered representations with nested dropout 31

Learning ordered representations with nested dropout

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31st International Conference on Machine Learning, ICML 2014

作者： Rippel, Oren Gelbart, Michael A. Adams, Ryan P. Department of Mathematics School of Engineering and Applied Sciences Harvard University United States Program in Biophysics School of Engineering and Applied Sciences Harvard University United States

ISBN: (纸本)9781634393973

In this paper, we present results on ordered representations of data in which different dimensions have different degrees of importance. To learn these representations we introduce nested dropout, a procedure for stochastically removing coherent nested sets of hidden units in a neural network. We first present a sequence of theoretical results for the special case of a semi-linear autoencoder. We rigorously show that the application of nested dropout enforces identifiability of the units, which leads to an exact equivalence with PCA. We then extend the algorithm to deep models and demonstrate the relevance of ordered representations to a number of applications. Specifically, we use the ordered property of the learned codes to construct hash-based data structures that permit very fast retrieval, achieving retrieval in time logarithmic in the database size and independent of the dimensionality of the representation. This allows codes that are hundreds of times longer than currently feasible for retrieval. We therefore avoid the diminished quality associated with short codes, while still performing retrieval that is competitive in speed with existing methods. We also show that ordered representations are a promising way to learn adaptive compression for efficient online data reconstruction. Copyright 2014 by the author(s).

关键词： Learning systems

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