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Stability analysis of intermittently jointed rock slopes based on the stepped failure mode

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Journal of Mountain Science 2024年第3期21卷 1019-1035页

作者： li dejian FU Junwen li Hekai CHENG Xiao ZHAO lianheng ZHANG Yingbin PENG Xinyan School of Civil Engineering Southwest Jiaotong UniversityChengdu 610031China Institute for Disaster Management and Reconstruction College of Architecture&EnvironmentSichuan UniversityChengdu 610065China School of Civil Engineering Key Laboratory of Heavy-Haul Railway Engineering StructureMinistry of EducationHunan Provincial Key Laboratory for Disaster Prevention and Mitigation of Rail Transit Engineering StructureCentral South UniversityChangsha 410075China

In practical engineering,due to the noncontinuity characteristics of joints in rock slopes,in addition to plane failure,stepped sliding failure may occur for intermittently jointed rock *** for intermittently bedding jointed rock slopes,the correlation and difference in strength parameters between joints and rock bridges,along with the various failure modes and intermittency of rock bridges,contribute to the complexity of stepped failure modes and the unpredictability of failure *** on the upper-bound limit analysis method and multi-sliders step-path failure mode,considering the shear and tensile failure of rock bridges and the weakened relationship between the strength parameters of rock bridges and jointed surfaces,by introducing the modified M-C failure criterion and the formula for calculating the energy consumption of tensile failure of rock bridges,two failure mechanisms are constructed to obtain the safety factor(F_(s))of intermittently jointed rock *** sequential quadratic programming method is used to obtain the optimal upper-bound solution for F_(s).The influence of multiple key parameters(slope height H,horizontal distance L,Slope angleβ,shear strength parameters of the rock bridgeφr and cr,Dimensionless parameter u,weakening coefficients of the internal friction angle and cohesion between the rock bridges and joint surfaces Kφand Kc)on the stability analysis of intermittently jointed rock slopes under the shear failure mode of rock bridges as well as under the tensile failure mode is also *** reliability of the failure mechanisms is verified by comparative analysis with theoretical results,numerical results,and landslide cases,and the variation rules of F_(s)with each key parameter are *** results show that F_(s) varies linearly withφr and cr of the rock bridge and with K_(φ)and K_(c),whereas F_(s)changes nonlinearly with H and *** particular,with the increase in Kφand Kc,Fs increases by approximately 52.

关键词： Jointed rock slopes Stepped sliding failure Weakening characteristics Modified M‒C failure criterion

Research on denoising of joint detection signal of water quality with multi-parameter based on IEEMD

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Optoelectronics Letters 2024年第2期20卷 107-115页

作者： li Wen li dejian MA Yongyue TIAN Wang WEN Xin li Jie Institute of Mechanical and Electrical Engineering North China University of TechnologyBeijing 100144China1

An improved ensemble empirical mode decomposition(IEEMD) is suggested to process water quality spectral signals in order to address the issue that noise interference makes it difficult to extract and evaluate water quality spectral *** algorithm effectively solves the problems of modal mixing,poor reconstruction accuracy in the empirical mode decomposition(EMD),and a large amount of calculation in the ensemble empirical mode decomposition(EEMD).Based on EEMD,IEEMD firstly preprocesses the original water quality spectral signals,then performs Savitzky-Golay(S-G) smoothing on the decomposed effective intrinsic mode function(IMF) components,and finally reconstructs them to obtain the denoised *** sample data at different concentrations can be accurately analyzed based on the noise-reduced spectral *** this paper,three water quality parameters are used as research objects:benzene(C_(6)H_(6)),benzo(b)fluoranthene(C_(20)H_(12)),and chemical oxygen demand(COD).The original water quality multi-parameter(C_(6)H_(6),C_(20)H_(12),COD) spectral signals were subjected to denoising based on the IEEMD and the water quality multi-parameter joint detection *** signal-to-noise ratio(SNR) and the correlation coefficient(R^(2)) of the fitted curves obtained from the processing of the IEEMD were compared and analyzed with those obtained from the processing of the EMD and the *** experimental results show that the SNR of the spectral signals and the R^(2) of the fitting curve in three water quality parameters have been significantly ***,the IEEMD effectively improves the phenomenon of modal mixing,reduces the amount of calculation,improves the reconstruction accuracy,and provides an important guarantee for the effective extraction of multi-parameter spectral signals of water quality.

关键词： signal parameter noise

Fragmentation characteristics analysis of sandstone fragments based on impact rockburst test

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Journal of Rock Mechanics and Geotechnical Engineering 2014年第3期6卷 251-256页

作者： Dongqiao liu dejian li Fei Zhao Chengchao Wang State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and Technology School of Mechanics and Civil Engineering China University of Mining and Technology

Impact rockburst test on sandstone samples with a central hole is carried out under true triaxial static loads and vertical dynamic load conditions, and rock fragments after the test are collected. The fragments of sandstone generated from strain rockburst test and uniaxial compression test are also collected. The fragments are weighed and the length, width and thickness of each piece of fragments are measured respectively. The fragment quantities with coarse, medium, fine and micro grains in different size ranges, mass and particles distributions are also analyzed. Then, the fractal dimension of fragments is calculated by the methods of size-frequency, mass-frequency and length-to-thickness ratio-frequency. It is found that the crushing degree of impact rockburst fragments is higher, accompanied with blocky character- istics observably. The mass percentage of small grains, including fine and micro grains, in impact rock- burst test is higher than those in strain rockburst test and uniaxial compression test. Energy dissipation from rockburst tests is more than that from uniaxial compression test, as the quantity of micro grains generated does.

关键词： Impact rockburst testFragmentsFragmentation characteristicsFractal dimension

Fast Fourier transform convolutional neural network accelerator based on overlap addition

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The Journal of China Universities of Posts and Telecommunications 2024年第5期31卷 71-84页

作者： You Chen li dejian Feng Xi Shen Chongfei Wei Jizeng liu Yu School of Microelectronics Tianjin UniversityTianjin 300072China Beijing Smart-Chip Microelectronics Technology Company limited Beijing 102200China College of Intelligence and Computing Tianjin UniversityTianjin 300072China

In convolutional neural networks(CNNs), the floating-point computation in the traditional convolutional layer is enormous, and the execution speed of the network is limited by intensive computing, which makes it challenging to meet the real-time response requirements of complex applications. This work is based on the principle that the time domain convolution result equals the frequency domain point multiplication result to reduce the amount of floating-point calculations for convolution. The input feature map and the convolution kernel are converted to the frequency domain by the fast Fourier transform(FFT), and the corresponding point multiplication is performed. Then the frequency domain result is converted back to the time domain, and the output result of the convolution is obtained. In the shared CNN, the input feature map is much larger than the convolution kernel, resulting in many invalid operations. The overlap addition method is proposed to reduce invalid calculations and speed up network execution better. This work designs a hardware accelerator for frequency domain convolution and verifies its efficiency on the Xilinx Zynq UltraScale+MPSoC ZCU102 board. Comparing the calculation time of visual geometry group 16(VGG16) under the ImageNet dataset faster than the traditional time domain convolution, the hardware acceleration of frequency domain convolution is 8.5 times.

关键词： convolutional neural network(CNN) fast Fourier transform(FFT) overlap addition

Design and Optimization of Winograd Convolution on Array Accelerator

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Journal of Beijing Institute of Technology 2023年第1期32卷 69-81页

作者： Ji Lai lixin Yang dejian li Chongfei Shen Xi Feng Jizeng Wei Yu liu School of Microelectronics Tianjin UniversityTianjin 300072China Beijing Smart-Chip Microelectronics Technology Company limited Beijing 100192China College of Intellegence and Computing Tianjin UniversityTianjin 300072China

With the rapid development and popularization of artificial intelligence technology,convolutional neural network(CNN)is applied in many fields,and begins to replace most traditional algorithms and gradually deploys to terminal ***,the huge data movement and computational complexity of CNN bring huge power consumption and performance challenges to the hardware,which hinders the application of CNN in embedded devices such as smartphones and smart *** paper implements a convolutional neural network accelerator based on Winograd convolution algorithm on field-programmable gate array(FPGA).Firstly,a convolution kernel decomposition method for Winograd convolution is *** convolution kernel larger than 3×3 is divided into multiple 3×3 convolution kernels for convolution operation,and the unsynchronized long convolution operation is ***,we design Winograd convolution array and use configurable multiplier to flexibly realize multiplication for data with different *** results on VGG16 and AlexNet network show that our accelerator has the most energy efficient and 101 times that of the CPU,5.8 times that of the *** the same time,it has higher energy efficiency than other convolutional neural network accelerators.

关键词： convolutional neural network Winograd convolution algorithm accelerator

Remodeling Electrophysiological Microenvironment for Promoting Bone Defect Repair via Electret Hybrid Electrospun Fibrous Mat

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Advanced Fiber Materials 2024年第6期6卷 1855-1873页

作者： Jinjie Cui Bin Yu dejian li Zeyu Fu Xiuyi Yang lingyong Jiang Xudong Wang Kaili lin Department of Oral and Cranio‑Maxillofacial Surgery College of StomatologyNational Center for StomatologyNational Clinical Research Center for Oral DiseasesShanghai Key Laboratory of StomatologyResearch Unit of Oral and Maxillofacial Regenerative MedicineShanghai Ninth People’s HospitalShanghai Jiao Tong University School of MedicineChinese Academy of Medical SciencesShanghai 200011China State Key Lab for Modification of Chemical Fibers&Polymer Materials College of Material Science&EngineeringDonghua UniversityShanghai 201620China Department of Orthodontics The Affiliated Stomatological Hospital of Soochow UniversitySuzhou Stomatological HospitalSuzhou 215005China

Improving the osteogenic properties of bone grafts plays a critical role in the repair and functional restoration of critical-sized bone *** endogenous electric field,one of the most crucial physiological signals,has been confirmed to maintain physiological function and reconstruct the structure of bone,which is inadequate in bone defect *** for the devel-opment of electroactive osteogenic biomaterials arise to remodel and promote the electrophysiological *** the electroactive materials,electret biomaterials can provide a stable and persistent endogenous electrical stimulation,which better conforms to the physiological microenvironment and has long-term effectiveness in the bone repair ***,an electret hybrid electrospun fibrous mat(EHFM)was developed to mimic the structure of the natural extracellular matrix(ECM)with a suitable and persistent electrophysiological *** EHFM was constructed with a core-shell structure,in which silicon dioxide electrets were loaded in the core-layer to remodel and maintain the electrical microenvironment over the long *** EHFM significantly promoted the osteogenesis of bone mesenchymal stem cells(BMSCs)in vitro and showed remarkable ability in bone repair,which was three times better than that of the control group in a critical-sized rat calvarial defect ***,it was verified that EHFM-derived osteogenesis was related to the activation of the calcium ion-sensing receptor(CaSR),while increasing intracellular calcium ion concentration of *** study puts forward a novel engineering strategy to promote bone defect repair by remodeling a stable and persistent electrophysiological microenvironment,showing potential for clinical applications.

关键词： Electret Electrophysiological microenvironment Osteogenesis Electrospun fibrous mat

Analysis of microscopic pore structures of rocks before and after water absorption

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Mining Science and Technology 2011年第2期21卷 287-293页

作者： li dejian Wang Guilian Han liqiang liu Peiyu He Manchao Yang Guoxing Tai Qimin Chen Cheng State Key Laboratory of Geomechanics and Deep Underground Engineering Beijing 100083 China Institute of Geotechnical Engineering China University of Mining ＆ Technology Beijing 100083 China Sichuan Staff University of Science and Technology Sichuan 610101 China Engineering Research Institute of General Armament Department Beijing 100083 China

Hydrophilic characteristics of rocks are affected by their microscopic pore structures,which clearly change after water *** absorption tests and scanning electron microscopic（SEM） experiments on rock samples,located at a site in Tibet,China,were carried out Changes of rock pore structures before and after water absorption were studied with the distribution of pore sizes and fractal characteristics of *** results show that surface porosities,fractal dimensions of pores and the complexity of pore structures increased because the number of new small pores produced increased or the original macropore flow channels were expanded after rocks absorbed *** were points of inflection on their water absorption *** water absorption of other rocks,surface porosities and fractal dimensions of pores and complexity of pore structures decreased as the original pore flow channels became *** absorption curves did not *** porosity and the pore fractal dimensions of rocks have good linear relationships before and after water absorption.

关键词： Hydrophilic characteristics Pore structures Pore size distribution Pore fractal characteristics

Detection of Sunken Defects on the FPC Trace

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Instrumentation 2017年第2期4卷 1-8页

作者： li dejian YUAN Weiqi Computer Vision Group Shenyang University of Technology

Trace is the important composition structure of printed circuit board,w hich connects the devices,it is also the module that taking up the highest proportion,thus,it is the major testing target of quality assurance. The sunken defects proposed in this paper is a w idth abnormity defect on the FPC trace,w hich w ould cause the latent open circuit defect and affect the electrical function of circuit. The problem of flexible deformation and w idth difference make the FPC trace detection harder. Therefore,this paper proposed a detection scheme combined w ith linear masks and circle distribution characteristic. Firstly,this scheme preprocessed the acquired FPC image,divided the trace into several sub-regions and obtained the line w idth values of each trace transverse section. Then the line w idth sequences w ere searched w ith the linear difference template of gray scale. Thus,the sunken defects alternative positions w ere located. Lastly,the circle distribution characteristic is defined to identify the real defect areas from the alternative regions acquired from the previous step. Thus,the detection of sunken defects on the FPC trace w as *** algorithm w as tested in the self-built image database,w hich show s the better detection performance than the other typical algorithms.

关键词： FPC Trace Sunken Defect linear Difference Template line Width Sequences Circle Distribution Characteristic

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基于骨架的柔性变形FPC断路检测

仪器仪表学报 2017年第4期38卷 996-1004页

作者：苑玮琦李德健李绍丽沈阳工业大学视觉检测技术研究所沈阳110870 辽宁省机器视觉重点实验室沈阳110870

为了解决柔性印刷电路(FPC)翘曲变形容易导致图像出现柔性形变现象造成当前的FPC断路检测方法性能降低的问题,在建立柔性形变模型、分析形变机理的基础上,提出了一种基于骨架处理策略的检测方案。首先提取预处理后FPC图像的线路骨架,然... 详细信息

为了解决柔性印刷电路(FPC)翘曲变形容易导致图像出现柔性形变现象造成当前的FPC断路检测方法性能降低的问题,在建立柔性形变模型、分析形变机理的基础上,提出了一种基于骨架处理策略的检测方案。首先提取预处理后FPC图像的线路骨架,然后将其输入到建立的动态模板尺度空间(DTSS)模型中,以去除骨架的分支噪声、得到‘纯净’骨架;接着,提取上一步骤处理所得骨架的全部端点,并通过形态学操作和局部模板匹配定位线路异形结构区域,剔除该端点集合中处于异形结构区域内的噪声端点,从而得到断路端点集合,再根据集合中成员与图像位置的对应关系识别断路缺陷。在基于实际环境建立的SUT-F1图库上进行了算法效果验证,并与其他经典方法进行了对比分析。结果表明,本文方法具备良好的抗形变性能,检测正确率(CDR)高达99.30%,误检率(FDR)低至2.25%,表明了方法的有效性;相比于其他方法,CDR至少提高了5.03%,FDR最少降低了8.22%,显示了方法的优势,且具有一定的实际应用价值。

关键词：骨架柔性形变柔性印刷电路断路动态模板尺度空间