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Two-Stage Point Cloud Super Resolution with Local Interpolation and Readjustment via Outer-Product Neural Network

Journal of systems Science & complexity 2021年第1期34卷 68-82页

作者： WANG Guangyu XU Gang WU Qing WU Xundong School of Computer Science and Technology Hangzhou Dianzi UniversityHangzhou 310018China Key Laboratory of Complex Systems Modeling and Simulation Ministry of EducationHangzhou 310018China

This paper proposes a two-stage point cloud super resolution framework that combines local interpolation and deep neural network based readjustment. For the first stage, the authors apply a local interpolation method to increase the density and uniformity of the target point cloud. For the second stage, the authors employ an outer-product neural network to readjust the position of points that are inserted at the first stage. Comparison examples are given to demonstrate that the proposed framework achieves a better accuracy than existing state-of-art approaches, such as PU-Net, Point Net and DGCNN(Source code is available at https://***/qwerty1319/PC-SR).

关键词： Neural network outer-product network point cloud super resolution

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Interfacial Thermal Transport and Energy Dissipation in Multilayer PdSe2 Field Effect Transistors

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Advanced Materials 2025年第0期 e2503264页

作者： Xie, Jiaqiu Yu, Zehao Sun, Yuanchen Gan, Qikang Liu, Chenhan Wang, Lei Zhang, Lifa Zhao, Yunshan Phonon Engineering Research Center of Jiangsu Province Ministry of Education Key Laboratory of NSLSCS Center for Quantum Transport and Thermal Energy Science Institute of Physics Frontiers and Interdisciplinary Sciences School of Physics and Technology Nanjing Normal University Nanjing210023 China National Laboratory of Solid-State Microstructures School of Physics Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing210093 China Micro- and Nano-scale Thermal Measurement and Thermal Management Laboratory Jiangsu Key Laboratory for Numerical Simulation of Large-Scale Complex Systems School of Energy and Mechanical Engineering Nanjing Normal University Nanjing210046 China

The continuous miniaturization of 2D electronic circuits results in increased power density during device operation, leading to heat localization and placing higher demands on their performance thresholds. The risk to thermal breakdown and subsequent damage, due to the energy dissipation in the 2D semiconductor field-effect transistors (FETs) supported on the bulk substrates, represents a significant challenge in maintaining their optimal performance. Herein, this study investigates energy dissipation behavior in multilayer PdSe2 FETs for the first time. The high-field breakdown behavior is firstly studied in multilayer PdSe2 FETs on SiO2/Si substrates, where a maximum current density of ≈2.74 MA cm−2 is observed, which is comparable to that of multilayer black phosphorus FET and significantly higher—by about five times—than that of multilayer MoS2 FET. Additionally, the thermal boundary conductance (TBC) of PdSe2/SiO2 interface is measured at room temperature using Raman thermometry. The TBC is found to be ≈12–13 MW m−2 K−1, which is relatively low compared to the other known solid–solid interfaces, indicating that enhancing the performance of PdSe2 FETs can be possible by optimizing the TBC at the PdSe2/SiO2 interface. These findings provide valuable insights for design of high-quality and high-performance PdSe2 electronic and optoelectronic devices. © 2025 Wiley-VCH GmbH.

关键词： Multilayers

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A new general formulation of a transfer-function matrices of 2D digital systems

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Australian Journal of Electrical and Electronics Engineering 2019年第2期16卷 81-85页

作者： Bouhamla, Lakhdar Adamou-Mitiche, Amel Baha Houda Mitiche, Lahcène Laboratory of Research Modeling Simulation and Optimization of Real Complex Systems University Ziane Achour Djelfa Algeria

The contribution of our paper is a new simple method for transfer-function matrices derivation in two-dimensional digital systems from Roesser’s model is given. The main idea of this method is changing the form of the transfer-function, from state space to a fraction with a polynomial numerator and denominator. Then by identity, we can derive matrices of numerator and denominator. Numerical examples are given to prove the effectiveness and the simplicity of the proposed method. © 2019, © 2019 Engineers Australia.

关键词： Transfer functions

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O(1/t) complexity analysis of the generalized alternating direction method of multipliers

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Science China Mathematics 2019年第4期62卷 795-808页

作者： Xingju Cai Deren Han School of Mathematical Sciences and Key Laboratory for Numerical Simulation of Large Scale Complex Systems of Jiangsu Province Nanjing Normal University

Owing to its efficiency in solving some types of large-scale separable optimization problems with linear constraints, the convergence rate of the alternating direction method of multipliers(ADMM for short) has recently attracted significant attention. In this paper, we consider the generalized ADMM(G-ADMM), which incorporates an acceleration factor and is more efficient. Instead of using a solution measure that depends on a bounded set and cannot be easily estimated, we propose using the original ?-optimal solution measure, under which we prove that the G-ADMM converges at a rate of O(1/t). The new bound depends on the penalty parameter and the distance between the initial point and the solution set, which is more reasonable than the previous bound.

关键词： generalized alternating direction method of multipliers separable convex optimization iteration complexity sublinear convergence rate

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Relationship graph learning network for visual relationship detection 2

Relationship graph learning network for visual relationship ...

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2nd ACM International Conference on Multimedia in Asia, MMAsia 2020

作者： Li, Yanan Yu, Jun Zhan, Yibing Chen, Zhi Key Laboratory of Complex Systems Modeling and Simulation School of Computer Science and Technology Hangzhou Dianzi University Hangzhou China

ISBN: (纸本)9781450383080

Visual relationship detection aims to predict the relationships between detected object pairs. It is well believed that the correlations between image components (i.e., objects and relationships between objects) are significant considerations when predicting objects' relationships. However, most current visual relationship detection methods only exploited the correlations among objects, and the correlations among objects' relationships remained underexplored. This paper proposes a relationship graph learning network (RGLN) to explore the correlations among objects' relationships for visual relationship detection. Specifically, RGLN obtains image objects using an object detector, and then, every pair of objects constitutes a relationship proposal. All relationship proposals construct a relationship graph, in which the proposals are treated as nodes. Accordingly, RGLN designs bi-stream graph attention subnetworks to detect relationship proposals, in which one graph attention subnetwork analyzes correlations among relationships based on visual and spatial information, and the other analyzes correlations based on semantic and spatial information. Besides, RGLN exploits a relationship selection subnetwork to ignore redundant information of object pairs with no relationships. We conduct extensive experiments on two public datasets: the VRD and the VG datasets. The experimental results compared with the state-of-the-art demonstrate the competitiveness of RGLN. © 2021 ACM.

关键词： Semantics

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A first-principles study of the structural and elastic properties of orthorhombic and tetragonal Ca_3Mn_2O_7

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Chinese Physics B 2013年第6期22卷 465-471页

作者：张玮童培庆 Department of Physics Institute of Theoretical PhysicsNanjing Normal University Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University

The structural and elastic properties of multiferroic Ca3Mn2O7 with ferroelectric orthorhombic （O-phase） and paraelectric tetragonal structures （T-phase） have been studied by first-principles calculations within the generalized gradient approximation （GGA） and the GGA plus Hubbard U approaches （GGA ＋ U）. The calculated theoretical structures are in good agreement with the experimental values. The T-phase is found to be antiferromagnetic （AFM） and the AFM O-phase is more stable than the T-phase, which also agree with the experiments. On these bases, the single-crystal elastic constants （Cijs） and elastic properties of polycrystalline aggregates are investigated for the two phases. Our elasticity calculations indicate Ca3Mn2O7 is mechanically stable against volume expansions. The AFM O-phase is found to be a ductile material, while the AFM T-phase shows brittle nature and tends to be elastically isotropic. We also investigate the influence of strong correlation effects on the elastic properties, qualitatively consistent results are obtained in a reasonable range of values of U. Finally, the ionicity is discussed by Bader analysis. Our work provides useful guidance for the experimental elasticity measurements of Ca3Mn2O7, and makes the strain energy calculation in multiferroic Ca3Mn2O7 thin films possible.

关键词： elastic constant elastic anisotropy strong correlation effect multiferroic

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The effects of the Dzyaloshinskii-Moriya interaction on the ground-state properties of the XY chain in a transverse field

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Chinese Physics B 2013年第9期22卷 285-291页

作者：钟鸣徐卉刘小贤童培庆 Department of Physics and Institute of Theoretical Physics Nanjing Normal University Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University

The effects of the Dzyaloshinski-Moriya （DM） interaction on the ground-state properties of the anisotropic XY chain in a transverse field have been studied by means of correlation functions and entanglement. Different from the case without the DM interaction, the excitation spectra ek of this model are not symmetrical in the momentum space and are not always positive. As a result, besides the ferromagnetic （FM） and the paramagnetic （PM） phases, a gapless chiral phase is induced. In the chiral phase, the von Neumann entropy is proportional to log2 L （L is the length of a subchain） with the coefficient A ~ 1/3, which is the same as that of the XY chain in a transverse field without the DM interaction for 7 = 0 and 0 〈 h 〈 1. And in the vicinity of the critical point between the chiral phase and the FM （or PM） phase, the behaviors of the nearest- neighbor concurrence and its derivative are like those for the anisotropy transition.

关键词： Dzyaloshinskii-Moriya interaction the XY chain in a transverse field quantum entanglement,ground-state properties

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Query modeling for click data based image recognition using graph based propagation and sparse coding

Query modeling for click data based image recognition using ...

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9th International Conference on Internet Multimedia Computing and Service, ICIMCS 2017

作者： Wu, Weichen Tan, Min Zheng, Guangjian Yu, Jun Key Laboratory of Complex Systems Modeling and Simulation School of Computer Science and Technology Hangzhou Dianzi University Hangzhou310018 China

ISBN: (纸本)9789811085291

We address the fine-grained image recognition problem using user click data, wherein each image is represented as a semantical query-click feature vector. Usually, the query set obtained from search engines is large-scale and redundant. We propose a novel query modeling approach to merge semantically similar queries and construct a compact click feature. We represent each query as a click feature, and design a graph based propagation approach to predict the zero-clicks, ensuring similar images have similar clicks. Afterwards, using this feature, we formulate the problem as a sparse coding based recognition task, wherein the dictionary is discriminatively trained. We evaluate our method for fine-grained image recognition on the public Clickture-Dog dataset. It is shown that, the propagated click feature performs much better than the original one. Also, sparse coding performs better than K-means in query merging. © Springer Nature Singapore Pte Ltd. 2018.

关键词： Image recognition

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Control Design of Flight simulation Turntable Based on Model-Free Adaptive Control

Control Design of Flight Simulation Turntable Based on Model...

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2023 China Automation Congress, CAC 2023

作者： Yue, Mingtan Zhang, Yu Huo, Xin Control & Simulation Center Harbin Institute of Technology Harbin150080 China Beijing Simulation Center National Key Laboratory of Modeling and Simulation for Complex Systems Beijing100854 China

ISBN: (纸本)9798350303759

Aiming at the problem of periodic interference in flight simulation turntables, a design method of full-form dynamic linearization model free adaptive control (FFDL-MFAC) is proposed. An equivalent dynamic linearized data model is established at each dynamic operating point of the closed-loop system to achieve adaptive control of the nonlinear system, which gives the controller the advantage of online adjustment of internal parameters and improves the robustness of the control system. Aiming at the difficulty of parameter adjustment caused by the increase of dimension of the pseudo partial derivative matrix, a PID-like MFAC parameter adjustment method is proposed, which greatly reduces the difficulty of parameter adjustment of the model-free adaptive controller. The simulation results of MFAC and PID show that the designed FFDL-MFAC controller outperforms the conventional PID in tracking command signals and suppressing periodic disturbances. © 2023 IEEE.

关键词： Controllers

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Frequency and Voltage Computation on Protection Settings in Renewable Resources 4

Frequency and Voltage Computation on Protection Settings in ...

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4th IEEE Workshop on Power Electronics and Power Quality Applications (PEPQA)

作者： Arias-Guzman, S. Ustariz-Farfan, A. J. Cano-Plata, E. A. McCann, Roy Key Laboratory of Complex Systems Modeling and Simulation Ministry of Education Hangzhou Dianzi University Hangzhou China Computing Center Shanghai University Shanghai China

ISBN: (纸本)9781728116266

The presence of inverter based renewable resources has introducing new challenges on transmission systems due sudden loss of several MW after voltage and frequency excursions. These sudden disconnections have been related with a fault ride through control in voltage and frequency excursions following PRC-024 standard. The NERC Inverter-Based Resource Performance Task Force has expressed the necessity for a full ride-through standard with clear requirements as to how the resource can behave in terms on control and protection aspects. In consequence, this article addresses the problem to define the control and protection that can be taken under frequency and voltage excursions to avoid disconnections. For this purpose, this article proposes a new magnitude and frequency computation with computations delays under 16 ms and the use of new detection techniques to add new control and protection functions to the inverter based renewable resources.

关键词： Momentary Cessation Protection systems Frequency computation Estate estimation Renewable resources

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