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Why To Model Remote Sensing Measurements In 3d? Recent Advances In Dart: Atmosphere, Topography, Large Landscape, Chlorophyll Fluorescence And Satellite Image Inversion

Why To Model Remote Sensing Measurements In 3d? Recent Advan...

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International Conference on Advanced Technologies for Signal and Image Processing (ATSIP)

作者： J.P. Gastellu-Etchegorry Y. Wang O. Regaieg T. Yin Z. Malenovsky Z. Zhen X. Yang Z. Tao L. Landier A. Al Bitar Deschamps N. Lauret J. Guilleux E. Chavanon B. Cao J. Qi A. Kallel Z. Mitraka N. Chrysoulakis B. Cook D. Morton Université de Toulouse CESBIO - UPS CNES CNRS IRD Toulouse France Earth System Science Interdisciplinary Center University of Maryland College Park MD 20740-3823 USA School of Technology Environments and Design University of Tasmania Hobart Australia College of Geo-Exploration Science and Technology Jilin University Changchun China Chinese Academy of Sciences Institute of Remote Sensing and Digital Earth Beijing China Key Laboratory of Geographical Information Science East China Normal University Shanghai China CNES 18 Av. Belin Toulouse France Beijing Forestry University Beijing China CRNS ATMS Sfax Tunisia Foundation for Research and Technology Hellas (FORTH) Heraklion Greece NASA Goddard Space Flight Center Greenbelt USA

ISBN: (数字)9781728175133

ISBN: (纸本)9781728175140

Remote sensing (RS) dedicated to the study of land surfaces benefits from more and more advanced sensors. However, the interpretation of RS data is often is often inaccurate due to the complexity of the observed land surfaces. Therefore, RS models, in particular physical models, that simulate RS observations of the three-dimensional (3D) landscapes are critical to correctly interpret RS data. DART is one of the most comprehensive 3D models of Earthatmosphere optical radiative transfer (RT), from ultraviolet (UV) to thermal infrared (TIR). It simulates the optical signal of proximal, aerial and satellite imaging spectrometers and laser scanners, the 3D RB and solar-induced chlorophyll fluorescence (SIF) signal, for any urban or natural landscape and any experimental or instrument configuration. It is freely available for research and teaching activities (***). After illustrating three significant sources of inaccuracy in RS interpretation, five recent DART advances are presented: RT in the atmosphere and topography, fast RS image simulation of large landscapes, SIF modelling, and satellite image inversion.

关键词： Atmospheric modeling Three-dimensional displays Reflectivity Surface topography Sun Forestry Solid modeling

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Federated learning with differential privacy: Algorithms and performance analysis

arXiv

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arXiv 2019年

作者： Wei, Kang Li, Jun Ding, Ming Ma, Chuan Yang, Howard H. Farhad, Farokhi Jin, Shi Quek, Tony Q. S. Poor, H. Vincent School of Electrical and Optical Engineering Nanjing University of Science and Technology Nanjing210094 China Data61 Csiro SydneyNSW2015 Australia Singapore University of Technology and Design Information System Technology and Design Pillar Singapore National Mobile Communications Research Laboratory Southeast University Nanjing210096 China Department of Electrical Engineering Princeton University PrincetonNJ08544 United States

Federated learning (FL), as a manner of distributed machine learning, is capable of significantly preserving clients' private data from being exposed to external adversaries. Nevertheless, private information can still be divulged by analyzing on the differences of uploaded parameters from clients, e.g., weights trained in deep neural networks. In this paper, to effectively prevent information leakage, we propose a novel framework based on the concept of differential privacy (DP), in which artificial noises are added to the parameters at the clients side before aggregating, namely, noising before model aggregation FL (NbAFL). First, we prove that the NbAFL can satisfy DP under distinct protection levels by properly adapting different variances of artificial noises. Then we develop a theoretical convergence bound of the loss function of the trained FL model in the NbAFL. Specifically, the theoretical bound reveals the following three key properties: 1) There is a tradeoff between the convergence performance and privacy protection levels, i.e., a better convergence performance leads to a lower protection level;2) Given a fixed privacy protection level, increasing the number N of overall clients participating in FL can improve the convergence performance;3) There is an optimal number of maximum aggregation times (communication rounds) in terms of convergence performance for a given protection level. Furthermore, we propose a K-random scheduling strategy, where K (1 Copyright © 2019, The Authors. All rights reserved.

关键词： Deep neural networks

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Locomotion Mode Recognition based on Foot posture and Ground Reaction Force 15

Locomotion Mode Recognition based on Foot posture and Ground...

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15th International Conference on Ubiquitous Robots, UR 2018

作者： Zhu, Aibin Li, Ying Wu, Yuexuan Wu, Mengke Zhang, Xiaodong Key Laboratory of Intelligent Robot of Shaanxi Province Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System Xi'an Jiaotong University Xi'an710049 China Shaanxi University of Science Technology Xi'an710000 China

ISBN: (纸本)9781538663349

Efficient and accurate locomotion mode recognition is the basis and the key to compliance control of exoskeleton. Considering the fact that single ground reaction force information can not realize continuous gait phase recognition in the whole gait cycle and traditional inertial sensors' installation method tends to cause binding error, this paper established a wearable gait analysis system based on inertial sensor and foot pressure sensor which entirely embedded in a shoe insole. An inertial sensor mounting structure for foot posture information acquisition was designed to reduces the binding errors caused by the uncertain binding position and the random errors caused by the relative position changes with the movement. Two force sensors was set to measure the force load on the shoe insole at the heel and the forefoot during walking. Then, the gait curve of the normal human beings measured by this wearable gait analysis system is segmented by a periodic segmentation method combining power spectrum and feature points, and features is extracted from the time series of sensor signals according to the characteristics of the human gait. Probabilistic neural network is used to identify the locomotion modes and to verify the effectiveness of this wearable gait analysis system, experiments on different terrains are performed. The experiment results show that this method can effectively reduce binding error and random error, and reflect the foot movement during walking. Furthermore, the measurement method can accurately and effectively identify level-ground walking, stair ascent and stair decent, showing great potential for further development and applicability in control of exoskeleton. © 2018 IEEE.

关键词： Random errors

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Small Cluster Underwater Robot design with Variable Pitch Propeller 15

Small Cluster Underwater Robot design with Variable Pitch Pr...

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15th International Conference on Ubiquitous Robots, UR 2018

作者： Zhu, Aibin Song, Jiyuan Li, Ying Wu, Mengke Zhang, Xiaodong Key Laboratory of Intelligent Robot of Shaanxi Province Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System Xi'an Jiaotong University Xi'an710049 China Shaanxi University of Science Technology Xi'an710021 China

ISBN: (纸本)9781538663349

Most underwater robots use multiple sets of thrusters with motors and propellers to drive them independently that makes them bulky, inflexible and complex. In this paper, the propeller is innovatively designed that it can change the pitch that can be applied to underwater robots. The compact design, propeller response speed and high movement flexibility are the biggest advantage of this robot over current conventional designs. The movement of robot is controlled by three propellers and their rotations are driven by a common motor and each propeller is equipped with a servo to control the pitch. Transmission structure designed is symmetrical and compact that creates dynamic balance of the strong structure in itself. The retractable float completes the data transfer between the robot and the ground control also informs space assisted position of the robot when it is underwater and the float is outside of water. In addition, the robot also includes a matching electronic drive and remote control box. Basic movement requirements can be achieved through the independent and coordinated control of the three actuators of the robot. The actual underwater test of the robot verifies the flexibility and horizontal stability of the robot designed. The characteristics of carrying sensors in underwater robots to move more flexibly and effectiveness of the proposed control method is also verified in the actual water test. © 2018 IEEE.

关键词： Robots

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Research on Hydrodynamic Interference of a DSRV and a Wrecked Submarine

Research on Hydrodynamic Interference of a DSRV and a Wrecke...

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IEEE International Conference on Underwater system technology: Theory and Applications (USYS)

作者： Hao TAN Duanfeng HAN Lei JU Haitao ZHU Yiran MIAO College of Shipbuilding Engineering Harbin Engineering University Harbin 150000 China Science and Technology on Reactor System Design Technology Laboratory Unclear Power Institute of China Chengdu 610041 China

ISBN: (纸本)9781538694060

In this paper, the viscous flow method based on Computational Fluid Dynamics (CFD) is used to simulate the hydrodynamic interaction of the Deep Submergence Rescue Vehicle (DSRV) involved in the rescue of a wrecked submarine. As the object of study, the drag of the DSRV moving in unbounded flow field is numerically calculated and the calculation results are compared with the experimental values to validate the accuracy of the numerical method. When the DSRV approaches the wrecked submarine in a positive flotation in quasi-static way, the effects of different inflow velocities and the distance between the two objects on the DSRV's drag, lift and pitching moment are simulated and monitored. The results show that when the DSRV is far away from the wrecked submarine, it is subject to the repulsive force from the submarine; when the distance is gradually reduced, the repulsive force is reduced until becoming suction; when the two objects are docking, the DSRV is subjected to the repulsive force from the submarine. This study will provide a reference for the operation of DSRV drivers.

关键词： Underwater vehicles Mathematical model Hydrodynamics Force Numerical models Load modeling Drag

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An investigation of numerical performance enhancement of RELAP5: Numerical stability, higher resolution and an alternative constitutive relation

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Nuclear Engineering and design 2018年 328卷 309-320页

作者： Wei Li Xiaoli Wu Koroush Shirvan Guanghui Su Science Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu 610213 China Massachusetts Institute of Technology 77 Massachusetts Ave Cambridge MA 02139 USA School of Nuclear Science and Technology Xi’an Jiaotong University No. 28 Xianning West Road Xi’an Shanxi 710049 China

The nuclear reactor safety system code RELAP5 decomposes complex flow system of a nuclear reactor into a series of one-dimensional control volumes connected by flow junctions, and solves a set of two-phase two-fluid equations to predict the nuclear reactor system behavior. In spite of its extensive applications, there indeed exist many numerical shortcomings in RELAP5 and it is desirable to constantly improve its numerical performance. In the present work, the numerical performance improvement to RELAP5/MOD3 is carried out from the aspects of numerical stability, high-resolution and alternative constitutive relations. For the enhancement of numerical stability, the virtual mass term is replaced and an interfacial pressure term is added in the phase momentum equations of RELAP5 to make all the characteristic roots real, thus improve the model’s hyperbolicity. In addition, the second-order Minmod TVD flux-limiter scheme replaces the original first-order upwind scheme for advection terms to reduce the numerical diffusion. Furthermore, an alternative interphase friction relation is substituted for the built-in model in RELAP5 to calculate the interphase drag for bubbly/slug flow in the vertical bundle channels. The performance improvement measures work reasonably well, as indicated by the simulation of selected numerical examples and the Bethsy 6.2TC integral effect experiment which corresponds to an intermediate break Pressurized Water reactor Loss of Coolant Accident (PWR LOCA).

关键词： Virtual mass force Interfacial pressure Flux-limiter Interphase friction RELAP5

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Preliminary study on the radiation heat removal capacity in SMR core under high temperature condition

Preliminary study on the radiation heat removal capacity in ...

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2017 International Congress on Advances in Nuclear Power Plants: A New Paradigm in Nuclear Power Safety, ICAPP 2017

作者： Li, Zhongchun Ding, Shuhua Li, Songwei Deng, Jian Nulcear Power Institute of China Chengdu610041 China Science and Technology on Reactor System Design Technology Laboratory Chengdu610041 China

ISBN: (纸本)9784890471676

The advanced fuel design, such as accident tolerant fuel (ATF) was design concept to withstand the high temperatures for extreme condition. When it was equipped in reactor core, the heat removal by radiation would be quite considerable. The radiation heat removal in a simplified SMR core was studied in the present study. The calculation was assumed to be 2D and at steady state. The calculation models were established from fuel assembly to fuel rod. The radiation heat flux was calculated based on the heat balance model when the limitation temperature in the core was reached. The results showed that the radiation heat flux contribute large proportion when the limitation temperature on fuel clad was high. The radiation heat flux was increased with fuel clad temperature limitation value. The higher the emissivity was, the more radiation heat flux removed.

关键词： Temperature

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Identification of dynamic process response in DED-type additive manufacturing process and its application to process optimization

Identification of dynamic process response in DED-type addit...

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作者： Ueda, Masahiro Carter, David Yamazaki, Kazuo Kakinuma, Yasuhiro Department of System Design Engineering Faculty of Science and Technology Keio University 3-14-1 Hiyoshi Kouhoku-ku Yokohama-shi Kanagawa223-8522 Japan IMS-Mcchatronics Laboratory Department of Mechanical and Aerospace Engineering University of California Davis One Shields Avenue DavisCA95616 United States Precision Manufacturing Center Department of Mechanical Engineering University of California Berkeley Hearst Avenue BerkeleyCA94706 United States

For aiming at successful operation of directed energy deposition (DED) type additive manufacturing (AM) system, three different kinds of process elements, machine motion, powder supply and laser application, needs to be synchronously controlled for accurate shape creation of the work piece. In order to synchronize these elements, in this study, measurement method of these response delay time has been proposed. According to the method, using the specific DED type AM system, the response delay time has been identified as that of laser application is 0.72 ±0.2 second and the powder supply control has about 15 seconds response time delay while the evaluated response delay time of nozzle motion was negligible compared to that of other two elements. Using identified response characteristics, dead time compensation control has been adopted to absorb the response delay time of laser and powder application processes. Laser application commands were indicated prior to reaching targeted positions and a pseudo motion command was inserted to absorb the response delay time of powder supply before starting the subsequent actual deposition with the correct powder supplied amount. Performing experimental studies, target deposition shapes have been achieved without unintended deposition and effectiveness of the proposed optimization method has been confirmed. © 2019 Japan Society for Precision Engineering. All rights reserved.

关键词： Optimization

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PBDW method for state estimation: Error analysis for noisy data and nonlinear formulation

arXiv

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arXiv 2019年

作者： Gong, Helin Maday, Yvon Mula, Olga Taddei, Tommaso Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610041 China Paris75005 France Institut Universitaire de France Paris75005 France Université Paris-Dauphine PSL Research University CNRS UMR 7534 CEREMADE Paris75016 France IMB UMR 5251 Univ. Bordeaux Talence33400 France Inria Bordeaux Sud-Ouest Team MEMPHIS Talence33400 France

We present an error analysis and further numerical investigations of the Parameterized-Background Data-Weak (PBDW) formulation to variational Data Assimilation (state estimation), proposed in [Y Maday, AT Patera, JD Penn, M Yano, Int J Numer Meth Eng, 102(5), 933-965]. The PBDW algorithm is a state estimation method involving reduced models. It aims at approximating an unknown function utrueliving in a highdimensional Hilbert space from M measurement observations given in the form ym= m(utrue), m = 1, ⋯, M, where mare linear functionals. The method approximates utruewith u = z + η. The background Z belongs to an N-dimensional linear space ZNbuilt from reduced modelling of a parameterized mathematical model, and the update η belongs to the space UMspanned by the Riesz representers of (1, ⋯, M). When the measurements are noisy - i.e., ym= m(utrue) + ϵmwith ϵmbeing a noise term - the classical PBDW formulation is not robust in the sense that, if N increases, the reconstruction accuracy degrades. In this paper, we propose to address this issue with an extension of the classical formulation, which consists in searching for the background z either on the whole ZNin the noise-free case, or on a well-chosen subset KN⊂ ZNin presence of noise. The restriction to KNmakes the reconstruction be nonlinear and is the key to make the algorithm significantly more robust against noise. We further present an a priori error and stability analysis, and we illustrate the efficiency of the approach on several numerical examples. Copyright © 2019, The Authors. All rights reserved.

关键词： Parameterization

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Optimization of Machining Parameters of SiC Single Crystal Cut by Diamond Wire Saw

Optimization of Machining Parameters of SiC Single Crystal C...

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2018 2nd International Conference on Electronic Information technology and Computer Engineering (EITCE 2018)

作者： Lun Li Shaodong Yang Jishun Li School of Mechatronics Engineering Henan University of Science and Technology Henan Key Laboratory for Machinery Design and Transmission System Henan University of Science and Technology

For the process of optimizing the process parameters in the process of cutting the hard and brittle materials such as single-crystal SiC by diamond wire saw, the process parameters such as wire saw speed, workpiece feed speed and workpiece rotation speed are the design variables, and the sawing force and surface roughness are the processing targets by orthogonal experimental design. The grey system theory is introduced to optimize the multi-objective cutting process. According to the experimental data, the grey correlation resolution coefficient is determined. The significant relationship between the processing parameters and the target characteristics is analyzed. The optimal combination of process parameters under multi-target conditions is obtained, namely the workpiece feed rate is 0.025 mm/min, the wire saw speed is 1.6 m/s, and the workpiece rotating speed is 16 r/min.

关键词： Optimization of Machining Parameters of SiC Single Crystal Cut by Diamond Wire Saw SiC

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