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30th International Conference on Nuclear Engineering, ICONE 2023

作者： Ge, Wenjia Wen, Peizheng Li, Zhuofan Luo, Qi Zhao, Chen Wang, Jipu Yang, Ming Institute for Advanced Study in Nuclear Energy & Safety College of Physics and Optoelectronic Engineering Shenzhen University Shenzhen518060 China Nuclear Reactor System Design Technology Key Laboratory China Nuclear Power Research and Design Institute Chendu China

ISBN: (纸本)9784888982566

The method of characteristics (MoC) has become an accepted tool for lattice physics calculations. MoC has many advantages such as accurate representations of both the lattice geometry and the boundary conditions. The flat source (FS) approximation is most commonly used, and the linear source (LS) approximation can improve the accuracy by preserving higher order spatial moments of the neutron source. However, as a non-standard spatial discretization method, the order of accuracy of the spatial discretization is more difficult to obtain, especially for analyzing linear source approximation, because the MoC method utilizes two sets of spatial meshes - the FS mesh and the set of characteristic rays that integrate the transport equation over the FS mesh. In this work, we analyze the order of accuracy with spatial resolution in MoC in planar geometry for both FS and LS approximations and verify our predictions with the Method of Manufactured Solutions (MMS). It is shown that the flat source approximation is second order accurate and that the linear source approximation has a fourth order accuracy. © 2023 by JSME.

关键词： Nuclear reactors

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DPN: Decoupling Partition and Navigation for Neural Solvers of Min-max Vehicle Routing Problems 41

DPN: Decoupling Partition and Navigation for Neural Solvers ...

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41st International Conference on Machine Learning, ICML 2024

作者： Zheng, Zhi Yao, Shunyu Wang, Zhenkun Tong, Xialiang Yuan, Mingxuan Tang, Ke Department of Computer Science and Engineering Southern University of Science and Technology Shenzhen China Department of Computer Science City University of Hong Kong Hong Kong School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen China China Huawei Noah's Ark Lab Shenzhen China

The min-max vehicle routing problem (min-max VRP) traverses all given customers by assigning several routes and aims to minimize the length of the longest ***, reinforcement learning (RL)-based sequential planning methods have exhibited advantages in solving efficiency and ***, these methods fail to exploit the problem-specific properties in learning representations, resulting in less effective features for decoding optimal *** paper considers the sequential planning process of min-max VRPs as two coupled optimization tasks: customer partition for different routes and customer navigation in each route (i.e., partition and navigation).To effectively process min-max VRP instances, we present a novel attention-based Partition-and-Navigation encoder (P&N Encoder) that learns distinct embeddings for partition and ***, we utilize an inherent symmetry in decoding routes and develop an effective agent-permutation-symmetric (APS) loss *** results demonstrate that the proposed Decoupling-Partition-Navigation (DPN) method significantly surpasses existing learning-based methods in both single-depot and multi-depot minmax *** code is available at. Copyright 2024 by the author(s)

关键词： Sales

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Active Flow Control of Hydrodynamic Characteristics around a Square Cylinder with Symmetric Synthetic Jets 34th

Active Flow Control of Hydrodynamic Characteristics around a...

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34th International Ocean and Polar Engineering Conference, ISOPE 2024

作者： Ding, Hao Liu, Mingyue Zhou, Jihui Zhu, Shenglong State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Shanghai China SJTU YaZhou Bay Institude of Deepsea Science and Technology Sanya China System Design Institute of Hubei Aerospace Technology Academy Wuhan China

ISBN: (纸本)9781880653784

To explore the active control method of the square cylinder wake field modification, a self-developed piston-driven synthetic jet actuator is used to generate periodic blowing and suction jets through the slits to affect the external flow field. The flow characteristics around the square cylinder controlled by synthetic jet is experimentally investigated with the force measuring system and Particle Image Velocity (PIV) technique. The statistical fluid forces, the frequency characteristics, and the time-averaged flow flied are compared with different control parameters, i.e. jet exit angle (β), the momentum coefficient (Cμ), and the excitation frequency (f*). With control, dramatic reduction in CLrms (up to 61%) is attained and the corresponding value of CD is 12% at β =45°. Narrower and longer backflow region represents a decrease in flow-induced forces. © 2024 by the International Society of Offshore and Polar Engineers (ISOPE).

关键词： Jets

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DeepRank: Test Case Prioritization for Deep Neural Networks 35

DeepRank: Test Case Prioritization for Deep Neural Networks

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35th International Conference on Software Engineering and Knowledge Engineering, SEKE 2023

作者： Li, Wei Zhang, Zhiyi Jian, Yifan Liu, Chen Huang, Zhiqiu Collage of Computer Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing China Collaborative Innovation Center of Novel Software Technology and Industrialization Nanjing China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China School of Marxism Yangzhou University Yangzhou China Ministry Key Laboratory for Safety-Critical Software Development and Verification Nanjing University of Aeronautics and Astronautics Nanjing China

Deep neural networks (DNNs) have been widely used in safety-critical fields such as autonomous driving and medical diagnosis. However, DNNs are easily disturbed to make wrong decisions, which may lead to loss of life or property. Therefore, it is vital to test DNN adequately. In practice, to reveal the incorrect behavior of DNN and improve its robustness, testers usually need massive labeled data to test and optimize DNN. However, labeling test inputs to detect the correctness of DNN predictions is an expensive and time-consuming task that even affects the efficiency of DNN testing. To relieve the labeling-cost problem, we propose DeepRank, a test case prioritization technique based on cross-entropy loss. The key idea of DeepRank is that the higher the loss value of a test case relative to the DNN, the more likely it is to be mispredicted and the more conducive it is to improve the robustness of the DNN through retraining. Therefore, the cross-entropy loss value can be used for test case prioritization. We experimentally validate our approach on two datasets and three DNNs models. The experimental results demonstrate that DeepRank is significantly better than existing test case prioritization methods regarding fault-revealing capability and retraining effectiveness. © 2023 Knowledge systems Institute Graduate School. All rights reserved.

关键词： Deep neural networks

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Effect of Fission Defects on Tensile Strength of U3si2 Σ5(210) Grain Boundary from First-Principles Calculations

SSRN

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SSRN 2023年

作者： Zhao, Jiajun Sun, Dan Xi, Liu Chen, Ping Zhao, Jijun Wang, Yuanyuan Dalian University of Technology Liaoning Dalian China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Sichuan Chengdu China

U3Si2 is regarded as a promising accident tolerant fuel (ATF) to replace the commercial fuel UO2;however, U3Si2 grain boundary (GB) embrittlement caused by irradiation-induced defect segregation remains to be clarified. In this work, U3Si2 Σ5(210) symmetrically tilt GB is taken as representative to elucidate the individual effect of xenon (Xe) and vacancy on the tensile strength and failure of GB using first-principles calculations. Compared with the predicted segregation energies of defects at the most energetically favourable positions of GB, Si vacancy (VSi) has much stronger preference to segregate to GB than that of Xe substitution on Si sublattice (XeSi). Moreover, the strengthening/embrittlement potency of GB with single vacancy/Xe is evaluated using the first-principles-based uniaxial tensile test. Although both VSi and XeSi yield a weakening effect on the strength of U3Si2 Σ5(210) GB, such defective GBs exhibit significantly stronger interface strengths compared to the corresponding defects segregated to UO2 Σ3(111) GB. The underlying mechanism of strength change of U3Si2 GB is discussed in terms of charge analysis. Our results can provide fundamental understanding on the mechanical behavior of irradiated GB from an atomic perspective. © 2023, The Authors. All rights reserved.

关键词： Grain boundaries

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Study on hydrogen stratification and erosion process in Chinese SMR containment under severe accident scenario

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International Journal of Advanced Nuclear reactor design and technology 2020年 2卷 43-51页

作者： Fan, Yang Songwei, Li Wei, Zeng Zhifang, Qiu Jian, Deng Science and Technology on Reactor System Design Technology Laboratory NPIC China Design and Research Sub-institute NPIC China

During postulated severe accident, large amount of hydrogen-vapor mixture will be released into the containment and inflammable gas mixture may form. Once the gas will be ignited, the generated pressure loads can jeopardize the integrity of the internal structures. As the local accumulation of high content hydrogen related much to the stratification and erosion mechanism, it is therefore of interest whether a stratification of gas layers will form within small containment. In this study, a stratification/erosion experiment is performed and the criteria under which the steady stratification will be destroyed by steam jet discussed. Then the simulation method is validated by the experimental data. At last, several severe accident scenarios for Chinese SMR performed and one of them is adopted for containment hydrogen CFD analysis. It is shown that high content of hydrogen will form in the upper part of the containment, and clear gas stratification will form, such stratification will be enhanced due to the condensation effect of steel containment wall. © 2020

关键词： Hydrogen

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Greenhouse Heat Map Generation with Deep Neural Network Using Limited Number of Temperature Sensors 48

Greenhouse Heat Map Generation with Deep Neural Network Usin...

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48th Annual Conference of the IEEE Industrial Electronics Society, IECON 2022

作者： Sonoda, Ayu Takayama, Yuki Sugawara, Ayaki Nishi, Hiroaki Keio University Graduate School of Science and Technology Yokohama Japan Keio University Faculty of Science and Technology Department of System Design Yokohama Japan

ISBN: (数字)9781665480253

ISBN: (纸本)9781665480253

In recent years, there have been many attempts in smart agriculture to increase efficiency and profitability, especially in horticultural agriculture, where profitability is high. One of the measures to achieve this goal is to realize uniform quality by equalizing temperatures in greenhouses which have a huge influence on a process of growth. The most common method for measuring temperatures in greenhouses is the use of temperature sensors. However, to measure continuous temperature distribution by scattering temperature sensors, a large number of temperature sensors must be installed, a method that should be avoided because of its high cost. Therefore, the goal of this paper is to estimate the temperature of substances such as crops and soil in greenhouses, which are secondarily affected by the atmospheric temperature, at a low cost instead of measuring atmospheric temperatures in a costly way. Temperature sensors for substances must be directly attached to the target object to measure its surface temperature, which can lead to the deterioration in quality. In contrast, infrared array sensors can measure the surface temperature of materials from a distance. They have been increasingly used in recent years due to growing demand, and they can be used to measure the surface temperature of a wide range of objects in a greenhouse. However, infrared array sensors also have many operational problems, such as dirty lenses, and the measurement error is larger than that of temperature sensors. Therefore, this paper proposes a machine learning model that predicts continuous temperature distribution in the form of a 16 ×18 pixels heat map from a limited number of temperature sensors. Evaluation results show that our approach is useful in different greenhouse environments, including different airconditioning systems. In addition, the model is computationally inexpensive enough to run in practical fields with limited computational resources;therefore, it can be run on relatively

关键词： Atmospheric temperature

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Simulation and Calculation of Proximity Effect of Coils under Fast Transients 13

Simulation and Calculation of Proximity Effect of Coils unde...

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13th Asia-Pacific International Symposium on Electromagnetic Compatibility and Technical Exhibition, APEMC 2022

作者： Wang, Zongyang Song, Wenchang Xie, Yanzhao He, Xianjian Xi'An Jiaotong University State Key Laboratory of Electrical Insulation and Power Equipment School of Electrical Engineering Xi'an China Nuclear Power Institute of China Science and Technology on Reactor System Design Technology Laboratory Chengdu China

ISBN: (数字)9781665416719

ISBN: (纸本)9781665416719

Proximity effect over a broad frequency range plays an important role in analyzing transients in the coils. The frequency dependent characteristic makes proximity effect a tricky problem. This paper first introduces FEM simulation to calculate the complex impedance of proximity effect and compares different axial arrangement of two conductors, shows a good agreement. In addition, different formulas are used to compare their results with FEM simulation to verify their accuracy. Kane formula and Modified formula can both get relatively accurate results. Considering the accuracy and conciseness of Modified formula, it is preferred in the analysis of transients in coils. © 2022 IEEE.

关键词： Finite element method

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Super-Twisting Control for Re-entry Rigid-Elastic Coupled Hypersonic Vehicles

Super-Twisting Control for Re-entry Rigid-Elastic Coupled Hy...

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2023 China Automation Congress, CAC 2023

作者： Tang, Wentao Fan, Junfang Ji, Yi Li, Yafeng Xu, Xiaobin Zang, Luyao Beijing Information Science and Technology University Beijing Key Laboratory of High Dynamic Navigation Technology Beijing China School of Automation Beijing Information Science and Technology University Beijing China The System Design Institute of Mechan-ical-Electrical Engineering Beijing China

ISBN: (纸本)9798350303759

A super-twisting control strategy is proposed to tackle the complex problem of attitude stabilization control for rigid-elastic coupled hypersonic vehicles experiencing significant aerodynamic perturbations. Initially, the elastic modes are treated as uncertain factors, leading to the construction of a control-oriented dynamic model. To design the attitude subsystem, a combination of a super-twisting algorithm and a non-singular terminal sliding mode is proposed. A first-order differentiator is introduced to address the 'derivative explosion' issue commonly found in traditional control methods, thus eliminating the need for intricate differential computations. Moreover, a switching control strategy is integrated into the nonlinear feedback control law design, ensuring robust velocity tracking. Simulation results validate that the proposed control method surpasses conventional methods in both tracking performance and robustness. © 2023 IEEE.

关键词： Sliding mode control

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Optimization of Newton's Iterative Algorithm for Fractal Art Graphic design

Optimization of Newton's Iterative Algorithm for Fractal Art...

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2023 IEEE International Conference on Integrated Circuits and Communication systems, ICICACS 2023

作者： Wei, Jingying Tan, Yong College of Art and Design Guangdong University of Science and Technology Dongguan China Graduate School University of Perpetual Help System Dalta Manila Philippines

ISBN: (纸本)9798350398465

Graphic design is the main content of fractal art, but in graphic design, the amount of visual information and design means will affect the optimization results, reduce the accuracy of graphic design, and make the design optimization results unsatisfactory. Based on this, this paper proposes a Newtonian iterative algorithm to carry out graphic design on graphic data, improve the level of fractal art, and shorten the graphic design time. The graphical data is then comprehensively designed. Finally, the rule analysis produces artistic graphic design and outputs the final design optimization results. The research and optimization results show that Newton's iterative algorithm can accurately carry out graphic design and improve the level of graphic design, and the accuracy of graphic design is greater than 95%, which is better than the manual design method. Therefore, Newton's iterative algorithm can meet the optimization requirements of graphic design and is suitable for iterative analysis of fractal art. © 2023 IEEE.

关键词： Iterative methods

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