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Trajectory design and resource allocation for UAV energy minimization in a rotary-wing UAV-enabled WPCN

ALEXANDRIA ENGINEERING JOURNAL 2021年第1期60卷 1787-1796页

作者： Wang, Zhen Wen, Miaowen Dang, Shuping Yu, Lisu Wang, Yuhao Beijing Univ Posts & Telecommun Sch Informat & Commun Engn Beijing 100876 Peoples R China Nanchang Univ Sch Informat Engn Nanchang 330031 Jiangxi Peoples R China South China Univ Technol Sch Elect & Informat Engn Guangzhou 510641 Peoples R China King Abdullah Univ Sci & Technol KAUST Comp Elect & Math Sci & Engn Div Thuwal 239556900 Saudi Arabia Chinese Acad Sci Inst Comp Technol State Key Lab Comp Architecture Beijing 100190 Peoples R China

Due to the low efficiency of energy harvest (EH) for the traditional wireless powered communication network (WPCN), we propose a communication scheme based on unmanned aerial vehicle (UAV)-enabled WPCN, which can greatly improve the EH efficiency problem. In this paper, the UAV trajectory, time allocation, transmit power of UAVs, scheduling of wireless information transfer (WIT) and wireless power transfer (WPT) are jointly optimized to minimize the whole energy consumption. To solve the formulated non-convex problem with multiple constraints and attain locally optimal solution, an iterative algorithm is proposed. Simulations show that our proposed algorithm is superior to other benchmark algorithms. (C) 2020 The Authors. Published by Elsevier B.V. on behalf of Faculty of Engineering, Alexandria University. This is an open access article under the CC BY-NC-ND license (http://***/licenses/by-nc-nd/4.0/).

关键词： Energy harvest (EH) Wireless powered communi-cation network (WPCN) Unmanned aerial vehicle (UAV) UAV trajectory Non-convex problem iterative algorithm

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On Hermitian positive definite solutions of a nonlinear matrix equation

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JOURNAL OF FIXED POINT THEORY AND APPLICATIONS 2021年第2期23卷 1-19页

作者： Masoudi, Mohsen Salemi, Abbas Univ Guilan Fac Math Sci Rasht Iran Shahid Bahonar Univ Kerman Dept Appl Math Kerman Iran Shahid Bahonar Univ Kerman Mahani Math Res Ctr Kerman Iran

In this paper, the Hermitian positive definite solutions of the matrix equation X-s + A* X-t A = Q, where A is an n x n nonsingular complex matrix, Q is an n x n Hermitian positive definite matrix and s, t > 0, are discussed. Some conditions for the existence of Hermitian positive definite solutions of this equation are derived. In addition, two iterative methods to obtaining the maximum or minimum Hermitian positive definite solutions of this equation are proposed. In addition, a necessary and sufficient condition for the existence of these solutions is presented. Theoretical results are illustrated by some numerical examples.

关键词： Nonlinear matrix equation positive definite solution fixed point theorem iterative algorithm

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On the reconstruction of material properties of a radially inhomogeneous cylindrical waveguide

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MATHEMATICAL METHODS IN THE APPLIED SCIENCES 2021年第6期44卷 4756-4769页

作者： Vatulyan, Alexandr Ovanesovich Yurov, Victor Olegovich Southern Fed Univ II Vorovich Inst Math Mech & Comp Sci Rostov Na Donu Russia

The scheme of solving the inverse problem (IP) for reconstructing three functions characterizing the radial change in the Lame parameters and in the density in a cylindrical waveguide is presented. The displacement fields corresponding to three types of loading are used as an additional information for solving the IP. An iterative process is constructed, at each step of which a direct problem is solved for the radially inhomogeneous waveguide, and the corrections to the restored functions are determined. The corrections are identified by solving the system of three Fredholm integral equations of the first kind with smooth kernels. The solution is constructed by the A. N. Tikhonov regularization method. A series of computational experiments was carried out. The role of the initial approximation and the frequency range is discussed.

关键词： cylindrical waveguide inhomogeneous properties integral Fourier transform inverse problem iterative algorithm regularization

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Quasi-Optimization Problems: Existence, iterative algorithms and Well-Posedness

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JOURNAL OF OPTIMIZATION THEORY AND APPLICATIONS 2025年第2期206卷 1-21页

作者： Zeng, Shengda Nie, Qing Vetro, Calogero Chongqing Normal Univ Natl Ctr Appl Math Chongqing Chongqing 401331 Peoples R China Chongqing Normal Univ Sch Math Sci Chongqing 401331 Peoples R China Chongqing Jiaotong Univ Coll Math & Stat Chongqing 400074 Peoples R China Dept Math & Comp Sci Via Archirafi 34 I-90123 Palermo Italy

The aim of this article is to introduce and study a quasi-optimization problem (QOP, for short) on an infinite dimensional Banach space. First, under mild assumptions, we deliver three existence theorems for (QOP) by employing Kluge's fixed point principle for multivalued operators. Then, several sufficient and necessary conditions for a solution of (QOP) are proved. Furthermore, two iterative algorithms are proposed and the convergence results are obtained. Finally, the well-posedness and generalized well-posedness of (QOP) are introduced and its equivalent metric characteristic is established.

关键词： Quasi-optimization problem Existence Well-posedness iterative algorithm Sufficient and necessary condition

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A comparison of proton stopping power measured with proton CT and x-ray CT in fresh postmortem porcine structures

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MEDICAL PHYSICS 2021年第12期48卷 7998-8009页

作者： DeJongh, Don F. DeJongh, Ethan A. Rykalin, Victor DeFillippo, Greg Pankuch, Mark Best, Andrew W. Coutrakon, George Duffin, Kirk L. Karonis, Nicholas T. Ordonez, Caesar E. Sarosiek, Christina Schulte, Reinhard W. Winans, John R. Block, Alec M. Hentz, Courtney L. Welsh, James S. ProtonVDA LLC Naperville IL 60563 USA Northwestern Med Chicago Proton Ctr Warrenville IL USA Northern Illinois Univ Dept Phys De Kalb IL 60115 USA Northern Illinois Univ Dept Comp Sci De Kalb IL 60115 USA Argonne Natl Lab Data Sci & Learning Div 9700 S Cass Ave Argonne IL 60439 USA Loma Linda Univ Loma Linda CA 92350 USA Edward Hines Jr VA Med Ctr Radiat Oncol Serv Hines IL USA Loyola Univ Stritch Sch Med Dept Radiat Oncol 2160 S 1st Ave Maywood IL 60153 USA

Purpose: Currently, calculations of proton range in proton therapy patients are based on a conversion of CT Hounsfield units of patient tissues into proton relative stopping power. Uncertainties in this conversion necessitate larger proximal and distal planned target volume margins. Proton CT can potentially reduce these uncertainties by directly measuring proton stopping power. We aim to demonstrate proton CT imaging with complex porcine samples, to analyze in detail three-dimensional regions of interest, and to compare proton stopping powers directly measured by proton CT to those determined from x-ray CT scans. Methods: We have used a prototype proton imaging system with single proton tracking to acquire proton radiography and proton CT images of a sample of porcine pectoral girdle and ribs, and a pig's head. We also acquired close in time x-ray CT scans of the same samples and compared proton stopping power measurements from the two modalities. In the case of the pig's head, we obtained x-ray CT scans from two different scanners and compared results from high-dose and low-dose settings. Results: Comparing our reconstructed proton CT images with images derived from x-ray CT scans, we find agreement within 1% to 2% for soft tissues and discrepancies of up to 6% for compact bone. We also observed large discrepancies, up to 40%, for cavitated regions with mixed content of air, soft tissue, and bone, such as sinus cavities or tympanic bullae. Conclusions: Our images and findings from a clinically realistic proton CT scanner demonstrate the potential for proton CT to be used for low-dose treatment planning with reduced margins.

关键词： digitally reconstructed radiograph iterative algorithm proton computed tomography proton imaging proton radiography relative stopping power

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A constrained optimization method for blocking artifact compensation in JPEG infrared image

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SIGNAL IMAGE AND VIDEO PROCESSING 2021年第7期15卷 1361-1368页

作者： Pei, Jihong Mo, Wenying Shao, Xuhui Wang, Lixia Shenzhen Univ Sch Elect & Informat Engn Shenzhen 518060 Peoples R China

Aiming to improve the quality of JPEG decompressed infrared images, this paper presents a constrained optimization method for blocking artifact compensation. First, we define the drop value between image blocks and measure the DC component loss by the drop value. Second, a constrained optimization object function is constructed based on the DC component compensation model. Both global and local constraints are used to avoid overcompensation. Finally, the optimal compensation value is obtained using iterative processing. Experimental results show that the proposed algorithm can remove the blocking artifact in JPEG infrared image effectively and outperform the existing methods.

关键词： Blocking artifact removal DC component compensation Constrained optimization objective function iterative algorithm

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Sliding Mode Output Feedback Controller Design of Discrete-Time Markov Jump System Based on Hidden Markov Model Approach

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IEEE ACCESS 2021年 9卷 101089-101096页

作者： Xu, Ming Ma, Longhua Ma, Hongyu Xu, Zhaowen NingboTech Univ Inst Automat & Elect Engn Ningbo 315100 Peoples R China Zhejiang Cybstar Sci & Technol Co Ltd Hangzhou 311121 Peoples R China Shenzhen Polytech Inst Intelligence Sci & Engn Shenzhen 518055 Peoples R China

This paper investigates the problem of sliding mode controller design based on output feedback for discrete-time Markov jump systems. Considering the typical asynchronous phenomenon for jump systems, here we adopt the Hidden Markov Model (HMM) to quantify the asynchronous degree. Based on this, a static output feedback sliding surface is constructed. Sufficient conditions in terms of bilinear matrix inequalities are proposed ensuring the sliding motion dynamic to be stochastically stable and its H-infinity performance for the considered discrete time Markov jump systems. Moreover, the reachability of the sliding mode surface is ensured by a predesigned control law. The whole design scheme is presented by using an iterative algorithm. Finally, simulation results are presented to illustrate the effectiveness of the design methodology.

关键词： Markov processes Hidden Markov models Symmetric matrices Sliding mode control Output feedback Dynamics Licenses Sliding mode control HMM output feedback iterative algorithm

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Parameterizing the Curvilinear Roofs of Traditional Chinese Architecture

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NEXUS NETWORK JOURNAL 2021年第2期23卷 475-492页

作者： Shen, Yuan Zhang, Enhe Feng, Yanxiao Liu, Siyuan Wang, Julian Qingdao Univ Technol Coll Architecture & Urban Planning Qingdao 266033 Peoples R China Penn State Univ Dept Architectural Engn University Pk PA 16802 USA Univ Cincinnati Sch Architecture & Interior Design Cincinnati OH 45221 USA

The curvilinear roofs of ancient Chinese wooden architecture feature unique functional, hierarchical, and aesthetic elements. However, the digitalization of these roofs has yet to be explored because of the lack of accurate mathematical models for these roof geometries. This research aims to parameterize the design and construction rules for these roofs as stipulated in theYingzao fashi. We first illustrate the major features of curvilinear roofs, followed by a comprehensive investigation on the raising and bending rules via the original texts and drawing samples provided in theYingzao fashiand theAnnotated yingzao fashiby Sicheng Liang. Then, the mathematical models are developed. The main contribution of this research is the transformation of the design and building rules for complex curvilinear roofs into mathematical models, enabling designers to generate such roof architecture and adding new insights to existing mathematical methods in studying ancient architecture.

关键词： Parametric design iterative algorithm Traditional architecture Logic of design Roof architecture Chinese architecture

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Research on Dynamics Modeling and Simulation of Constrained Metamorphic Mechanisms

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IRANIAN JOURNAL OF SCIENCE AND TECHNOLOGY-TRANSACTIONS OF MECHANICAL ENGINEERING 2021年第2期45卷 321-336页

作者： Song, Yanyan Chang, Boyan Jin, Guoguang Wei, Zhan Li, Bo Zhu, Yongjie Tiangong Univ Sch Mech Engn Tianjin 300387 Peoples R China Tianjin Key Lab Modern Electromech Equipment Tech Tianjin 300387 Peoples R China

This paper presents a method for establishing a unified dynamics model of constrained metamorphic mechanisms. Based on the equivalent resistance, the influences of geometric constraints and/or force constraints on metamorphism are discussed, and the kinematic characteristics of metamorphic joints are described and analyzed in detail. On this basis, the metamorphic configurations of augmented Assur groups can be classified into three types, including non-collision, internal collision and external collision configurations, and the configuration complete dynamics models of augmented Assur groups are established. Then, the dynamics models of active parts, Assur groups and augmented Assur groups are summarized into a unified mathematical framework, and the unified dynamics model of constrained metamorphic mechanisms can be obtained. Based on the research mentioned above, the initial conditions of all components and the motion law of the active parts are given. The motion laws of all components, the driving force/torque of the active parts and the constraint force/torque of the metamorphic joints can be obtained by iteration and solution based on the theory that velocity and acceleration are same in an extremely brief period. Taking the planar double-folded metamorphic mechanism and the metamorphic nipper swing mechanism as examples, the computer numerical analysis and dynamic simulation are carried out to verify the correctness and effectiveness of the proposed theory and method.

关键词： Constrained metamorphic mechanisms Augmented Assur groups Dynamics iterative algorithm

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Fast iterative reconstruction for photoacoustic tomography using learned physical model: Theoretical validation

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PHOTOACOUSTICS 2023年 29卷 100452页

作者： Hsu, Ko-Tsung Guan, Steven Chitnis, Parag, V George Mason Univ Dept Bioengn Fairfax VA 22030 USA

iterative reconstruction has demonstrated superior performance in medical imaging under compressed, sparse, and limited-view sensing scenarios. However, iterative reconstruction algorithms are slow to converge and rely heavily on hand-crafted parameters to achieve good performance. Many iterations are usually required to reconstruct a high-quality image, which is computationally expensive due to repeated evaluations of the physical model. While learned iterative reconstruction approaches such as model-based learning (MBLr) can reduce the number of iterations through convolutional neural networks, it still requires repeated evaluations of the physical models at each iteration. Therefore, the goal of this study is to develop a Fast iterative Reconstruction (FIRe) algorithm that incorporates a learned physical model into the learned iterative reconstruction scheme to further reduce the reconstruction time while maintaining robust reconstruction performance. We also propose an effi-cient training scheme for FIRe, which releases the enormous memory footprint required by learned iterative reconstruction methods through the concept of recursive training. The results of our proposed method demon-strate comparable reconstruction performance to learned iterative reconstruction methods with a 9x reduction in computation time and a 620x reduction in computation time compared to variational reconstruction.

关键词： Photoacoustic tomography iterative algorithm Deep learning Image reconstruction Learned forward operator Neural operator

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