检索结果-内蒙古大学图书馆

Journal of Organometallic Chemistry 2016年 825-826卷 33-40页

作者： Tianzhi Yu Yanjun Bao Yuling Zhao Hui Zhang Zixuan Xu Xiaomeng Wu Key Laboratory of Opto-Electronic Technology and Intelligent Control (Ministry of Education) Lanzhou Jiaotong University Lanzhou 730070 China School of Chemical and Biological Engineering Lanzhou Jiaotong University Lanzhou 730070 China School of Materials Science and Engineering Southwest Jiaotong University Sichuan 611756 China

Two new red-emitting Ir(III) complexes containing 2-(1-naphthyl)benzothiazole as cyclometalated ligands and the carrier transporting group-functionalized picolinate as ancillary ligands have been successfully synthesized and characterized. The Ir(III) complexes have good thermal stability with less than 2% weight-reduction occurring at 285 °C, and exhibit strong red emissions. The doped light-emitting devices using the Ir(III) complexes as dopants were fabricated. The result indicated that the light-emitting devices fabricated by the carbazole-functionalized complex and the diaryl-1,3,4-oxadiazole-functionalized complex exhibited red emissions with a maximum brightness of 3074 and 2520 cd/m 2 at 10.7 V and a maximum current efficiency of 4.84 and 5.18 cd/A, respectively.

关键词： Iridium(III) complex 2-(1-Naphthyl)benzothiazole Photoluminescence Electroluminescence

Novel approach to avoid singularities of PUMA-type manipulators

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Zidonghua Xuebao/Acta Automatica Sinica 2008年第6期34卷 670-675页

作者： Xu, Wen-Fu Liang, Bin Liu, Yu Li, Cheng Qiang, Wen-Yi Institute of Space Intelligent System Harbin Institute of Technology Harbin 150001 China Department of Control Science and Engineering Harbin Institute of Technology Harbin 150001 China

Existing methods to avoid the kinematic singularities are complex. A novel approach (named singularity separation plus damped reciprocal method) is proposed for PUMA-type manipulators. Firstly, we analyze the singularity conditions and separate the singularity parameters from the Jacobian inverse. Then, the damped reciprocals are used to avoid the singularities by replacing their reciprocals. Since the SVD decomposition and the estimate of the minimum singularity value are not required, the algorithm is more efficient and fit for real-time application. And not all components of the end-effector velocities are sacrificed in accuracy. The method can be used for prescribed or real-time trajectory tracking. Simulation and experiment results verify the method.

关键词： Motion planning

Characterizing The Groundwater Circulation Of Gently Inclined Soil Landslides Along The Soil-Bedrock Interface Based on in Situ Monitoring and Electrical Resistivity Tomography (Wangzhengbang Landslide, Southwest China)

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SSRN 2023年

作者： Wang, Weizao Xu, Qiang An, Junpeng Shao, Wenyuan Liu, Xiaoyang Hebei GEO University Shijiazhuang050031 China State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of Technology Chengdu610059 China Hebei Technology Innovation Center for Intelligent Development and Control of Underground Built Environment Hebei Shijiazhuang050031 China Key Laboratory of Intelligent Detection and Equipment for Underground Space of Beijing-Tianjin-Hebei Urban Agglomeration Ministry of Natural Resources Shijiazhuang050031 China

Abstract: The groundwater circulation characteristics of earthy slopes play a key role in the instability of landslides. To ascertain the migration characteristics of groundwater in earthy slopes, we conducted field double-ring infiltration tests,rainfall monitoring test, real-time pore water pressure monitoring test, and electrical resistivity tomography (ERT) tests on the Wangzhengbang landslide in Southwest China. The results of the field double-ring infiltration tests on the Wangzhengbang landslide revealed that the permeability coefficient at different parts of the slope varies greatly, ranging from 3.66e-5 to 1.15e-7m/s from the top and bottom of the investigated slope, *** results of rainfall monitoring test and real-time pore water pressure monitoring test on the Wangzhengbang landslide revealed that (1) the overall change in the groundwater level is not large in the flood season;(2) the groundwater level rises with heavy rain, then drops slightly and remains above the soil-bedrock interface after the rain stops;(3) the pore water pressure decayed rapidly, the groundwater level gradually decreased, and the groundwater level dropped gradually below the interface of soil-bedrock after the flood season;(4) the groundwater level changed with the rainfall process, but the response of the groundwater level was later than the rainfall *** from the ERT tests on the Wangzhengbang landslide revealed that (1) the water in the soil is replenished by atmospheric rainfall and is discharged through surface evaporation or outward along the soil-bedrock interface from the distribution of the water content at different times after rainfall;(2) the surface soil is sensitive to rainfall, the water content of the surface soil fluctuates with the rainfall process, and the fluctuation range is large;(3) the main source of water in the surface soil is the vertical infiltration of rainfall;(4) the sources of water in the deep soil are vertical infiltration a

关键词： Landslides

Mitigating Low-Frequency Bias: Feature Recalibration and Frequency Attention Regularization for Adversarial Robustness

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arXiv

arXiv 2024年

作者： Zhang, Kejia Weng, Juanjuan Cai, Yuanzheng Luo, Zhiming Li, Shaozi Department of Artificial Intelligence Xiamen University Xiamen361005 China Fujian Provincial Key Laboratory of Information Processing and Intelligent Control College of Computer and Control Engineering Minjiang University Fuzhou350108 China College of Information Science and Technology Jinan University Guangzhou510632 China

Ensuring the robustness of deep neural networks against adversarial attacks remains a fundamental challenge in computer vision. While adversarial training (AT) has emerged as a promising defense strategy, our analysis reveals a critical limitation: AT-trained models exhibit a bias toward low-frequency features while neglecting high-frequency components. This bias is particularly concerning as each frequency component carries distinct and crucial information: low-frequency features encode fundamental structural patterns, while high-frequency features capture intricate details and textures. To address this limitation, we propose High-Frequency Feature Disentanglement and Recalibration (HFDR), a novel module that strategically separates and recalibrates frequency-specific features to capture latent semantic cues. We further introduce frequency attention regularization to harmonize feature extraction across the frequency spectrum and mitigate the inherent low-frequency bias of AT. Extensive experiments demonstrate our method’s superior performance against white-box attacks and transfer attacks, while exhibiting strong generalization capabilities across diverse scenarios. Copyright © 2024, The Authors. All rights reserved.

关键词： Generative adversarial networks

Distributed mirror descent algorithm with bregman damping for nonsmooth constrained optimization

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arXiv

arXiv 2021年

作者： Chen, Guanpu Li, Weijian Xu, Gehui Hong, Yiguang Key Laboratory of Systems and Control Academy of Mathematics and Systems Science Beijing China School of Mathematical Sciences University of Chinese Academy of Sciences Beijing China Department of Automation University of Science and Technology of China Anhui Hefei China Department of Control Science and Engineering Shanghai Research Institute for Intelligent Autonomous Systems Tongji University Shanghai China

To solve distributed optimization efficiently with various constraints and nonsmooth functions, we propose a distributed mirror descent algorithm with embedded Bregman damping, as a generalization of conventional distributed projection-based algorithms. In fact, our continuous-time algorithm well inherits good capabilities of mirror descent approaches to rapidly compute explicit solutions to the problems with some specific constraint structures. Moreover, we rigorously prove the convergence of our algorithm, along with the boundedness of the trajectory and the accuracy of the solution. © 2021, CC0.

关键词： Mirrors

Rapid Detection of Incomplete Coal and Gangue Based on Improved Pspnet

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SSRN 2022年

作者： Wang, Xi Guo, Yongcun Wang, Shuang Cheng, Gang Wang, Xinquan He, Lei School of Mechanical Engineering Anhui University of Science and Technology Huainan232001 China State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines Anhui University of Science and Technology Huainan232001 China Mining Intelligent Technology and Equipment Provinces and Ministries jointly build a Collaborative Innovation Center Anhui University of Science and Technology Huainan232001 China

Aiming at the rapid identification difficulty of coal and gangue under the conditions of multi-scale, adhesion and half-occlusion, we propose a semantic segmentation network of coal and gangue image (SSNet_CG). The attention mechanism is embedded in the inverted residual block (IRB) to strengthen the detailed feature information of coal and gangue image;depthwise separable convolution (DSC) and atrous convolution (AC) are used to replace typical convolution to reduce the number of parameters;The pyramid pooling module(PPM)'s structure is optimized to minimize parameter redundancy;Two feature fusion channels are added to refine the segmentation boundary of coal and gangue in an adhesive state by connecting the preceding position information. The results show that our method has the best effects, the MPA, mIoU and F1_scores are respectively 97.3, 95.4 and 0.98, and the single image test time is 0.027s. This method can accurately identify multi-scale and partially blocked coal and gangue. © 2022, The Authors. All rights reserved.

关键词： Coal

A Many-Objective Evolutionary Algorithm Assisted by Ideal Hyperplane

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SSRN 2022年

作者： Zhang, Zhixia Wen, Jie Wang, Hui Cai, Xingjuan Cui, Zhihua Zhang, Wensheng School of Computer Science and Technology Taiyuan University of Science and Technology China School of Information Engineering Nanchang Institute of Technology Nanchang330099 China State Key Laboratory of Intelligent Control and Management of Complex System Institute of Automation Chinese Academy of Sciences China State Key Lab. for Novel Software Technology Nanjing University China

In many-objective optimization problems (MaOPs), it is a difficult task for evolutionary algorithms to balance convergence and diversity while rapidly converging to the Pareto front. As the number of objectives increases, the difficulty of evolutionary algorithms increases with individual selection pressure. To address above problems, we propose a many-objective evolution algorithm assisted by an ideal hyperplane (MaOEA-IH). Firstly, the ideal hyperplane as a reference surface to guide the individual to search the Pareto front, which is established from the extremum of each dimension of the objective space. Secondly, a parallel p -norm mating selection strategy is proposed to improve convergence. In addition, two factors are considered in this strategy: 1) different p -norm are used to measure different spatial scales;2) individual selection uncertainty is defined by incorporating a probabilistic perturbation mechanism. Thirdly, the improved shift-based density estimation strategy is used as the evaluation criterion for environmental selection to improve the convergence and diversity of solution sets and enhance selection pressure. To verify the effectiveness of the proposed algorithm, MAOEA-IH is compared with seven excellent algorithms in three benchmark sets (DTLZ, WFG and MaF). The results show that the proposed MAOEA-IH is highly competitive in solving MaOPs. © 2022, The Authors. All rights reserved.

关键词： Geometry

A survey on negative transfer

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arXiv

arXiv 2020年

作者： Zhang, Wen Deng, Lingfei Zhang, Lei Wu, Dongrui the Key Laboratory of the Ministry of Education for Image Processing and Intelligent Control School of Artificial Intelligence and Automation Huazhong University of Science and Technology Wuhan430074 China the School of Microelectronics and Communication Engineering Chongqing University Chongqing400044 China

—Transfer learning (TL) utilizes data or knowledge from one or more source domains to facilitate the learning in a target domain. It is particularly useful when the target domain has very few or no labeled data, due to annotation expense, privacy concerns, etc. Unfortunately, the effectiveness of TL is not always guaranteed. Negative transfer (NT), i.e., leveraging source domain data/knowledge undesirably reduces the learning performance in the target domain, has been a long-standing and challenging problem in TL. Various approaches have been proposed in the literature to handle it. However, there does not exist a systematic survey on the formulation of NT, the factors leading to NT, and the algorithms that mitigate NT. This paper fills this gap, by first introducing the definition of NT and its factors, then reviewing about fifty representative approaches for overcoming NT, according to four categories: secure transfer, domain similarity estimation, distant transfer, and NT mitigation. NT in related fields, e.g., multi-task learning, lifelong learning, and adversarial attacks, are also discussed. Copyright © 2020, The Authors. All rights reserved.

关键词： Surveys

A Multiple-Image Authentication Method Based on Phase-Only Hologram and Logistic Map

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SSRN 2024年

作者： Liansheng, Sui Zishan, Jiang Haiwei, Lu Zhaolin, Xiao Tianyu, Zeng School of Computer Science and Engineering Xi’an University of Technology Xi’an710048 China Shaanxi Key Laboratory for Network Computing and Security Technology Xi’an710048 China Hebei Normal University Shijiazhuang050024 China Hebei Provincial Key Laboratory of Information Fusion and Intelligent Control Shijiazhuang050024 China

An interesting security method for multiple-image authentication scheme is proposed based on computer-generated holograms and logistic map. First, each original image is encoded as the complex-valued hologram under the point light source model. The resulting hologram is then converted to a phase-only hologram using the Floyd-Steinberg dithering algorithm. Second, each phase-only hologram is randomly sampled by the aid of a binary mask. Through the catenation of all selected pixels, a phase-only pixel sequence is formed. Finally, a non-periodic and non-converging sequence generated with logistic map is used to scramble this sequence. After only preserving the phase data of the scrambled sequence, the real-valued ciphertext carrying the information of all original images is obtained. In the process of authentication, although no valid information can be discerned from noisy reconstructed images at a small sampling rate, the verification of original images can be efficiently accomplished using the nonlinear correlation maps. Besides binary masks, the parameters of logistic map are served as secret keys. Due to their high sensitivity, the security of the proposed method is greatly enhanced. The proposed authentication mechanism has been demonstrated to be effective and robust through experiments. To our best knowledge, it is first time to implement multiple-image authentication using phase-only holograms, which can provide a new perspective for optical information security. © 2024, The Authors. All rights reserved.

关键词： Holograms

Bit Bounce Detection for Drilling Process Based on Multi-Feature Graph and Graph Convolutional Network

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Bit Bounce Detection for Drilling Process Based on Multi-Fea...

Annual Conference of Industrial Electronics Society

作者： Peng Zhang Wenkai Hu Weihua Cao Min Wu Jiandong Wang School of Automation China University of Geosciences Wuhan China Hubei Key Laboratory of Advanced Control and Intelligent Automation for Complex Systems Wuhan China Ministry of Education Engineering Research Center of Intelligent Technology for Geo-Exploration Wuhan China College of Electrical Engineering and Automation Shandong University of Science and Technology Qingdao Shandong Province China

Prompt detection of bit bounce can prevent serious incidents and is of great importance for safe and efficient deep geological drilling. In the early stage of bit bounce, signal changes are relatively weak. In addition, there are differences in the topological relationships of samples at different time instances in normal state and bit bounce. These factors present a challenge to timely and accurate bit bounce detection. Therefore, this paper proposes a bit bounce detection method based on multi-feature graph and graph convolution networks. A multi-feature graph construction method using process variables, mean value, Mahalanobis distance, and Euclidean distance is proposed, and a two-layer graph convolutional network is designed to realize deep feature extraction and incident detection. The effectiveness and superiority of the proposed method are demonstrated by a real drilling industrial case.

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