检索结果-南通市图书馆

Predicting Rock Burst in Underground Engineering Leveraging a Novel Metaheuristic-Based LightGBM Model

Computer Modeling in Engineering & Sciences 2024年第7期140卷 229-253页

作者： Kai wang Biao He Pijush Samui Jian Zhou No.Three Engineering Co. Ltd.CCCC First Highway Engineering CompanyBeijing101102China Department of Civil Engineering Faculty of EngineeringUniversiti MalayaKuala Lumpur50603Malaysia Department of Civil Engineering National Institute of Technology PatnaBihar800005India School of Resources and Safety Engineering Central South UniversityChangsha410083China

Rock bursts represent a formidable challenge in underground engineering,posing substantial risks to both infrastructure and human *** sudden and violent failures of rock masses are characterized by the rapid release of accumulated stress within the rock,leading to severe seismic events and structural ***,the development of reliable prediction models for rock bursts is paramount to mitigating these *** study aims to propose a tree-based model—a Light Gradient Boosting Machine(LightGBM)—to predict the intensity of rock bursts in underground engineering.322 actual rock burst cases are collected to constitute an exhaustive rock burst dataset,which serves to train the *** population-basedmetaheuristic algorithms are used to optimize the hyperparameters of the LightGBM ***,the sensitivity analysis is used to identify the predominant factors that may incur the occurrence of rock *** results show that the population-based metaheuristic algorithms have a good ability to search out the optimal hyperparameters of the LightGBM *** developed LightGBM model yields promising performance in predicting the intensity of rock bursts,with which accuracy on training and testing sets are 0.972 and 0.944,*** sensitivity analysis discloses that the risk of occurring rock burst is significantly sensitive to three factors:uniaxial compressive strength(σc),stress concentration factor(SCF),and elastic strain energy index(Wet).Moreover,this study clarifies the particular impact of these three factors on the intensity of rock bursts through the partial dependence plot.

关键词： Rock burst prediction LightGBM coati optimization algorithm pelican optimization algorithm partial dependence plot

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

基于弹塑性理论的复杂截面导轨校直模型研究

引用

组合机床与自动化加工技术 2024年第7期 51-56,63页

作者：王永昱梁医沈永斌欧屹南京理工大学机械工程学院南京210094 浙江天裕型钢科技有限公司丽水323000

为解决具有复杂截面导轨的横向和纵向弯曲变形校直问题,建立校直挠度的理论模型,并给出明确的校直行程公式。首先,分析导轨基于线性强化弹塑性材料的弹塑性阶段应力与应变几何关系;其次,依据弯矩与应力的表达式,结合弯矩的轴向变化规律... 详细信息

为解决具有复杂截面导轨的横向和纵向弯曲变形校直问题,建立校直挠度的理论模型,并给出明确的校直行程公式。首先,分析导轨基于线性强化弹塑性材料的弹塑性阶段应力与应变几何关系;其次,依据弯矩与应力的表达式,结合弯矩的轴向变化规律,确定塑性阶段校直压力的范围,得到校直压力与总校直挠度和初始挠度的关系;最后,建立校直的理论计算模型。为验证理论模型的正确性,在ABAQUS中建立导轨的线性强化弹塑性力学模型,采用一端固定一端滑动的约束,加载头加载的方式,仿真校直压力与挠度之间的关系。结果表明,理论模型与有限元仿真的挠度与校直压力曲线规律完全一致,验证了理论模型的可行性与正确性。

关键词：直线导轨校直压力总校直挠度回弹挠度

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

基于凹槽结构的导管螺旋桨梢部流动研究

引用

船舶力学 2024年第6期28卷 866-876页

作者：金志辉王鹏董华超温志文丁永乐西安精密机械研究所西安710077 西北工业大学航海学院西安710072

针对导管螺旋桨的梢部流动,受压气机中“机匣处理”的启发,将矩形凹槽结构应用于导管内壁,用于降低导管螺旋桨梢涡强度和抑制梢涡空化,进而有望改善导管螺旋桨的水动力和空泡性能。采用计算流体力学方法,针对19A导管和Ka4-70螺旋桨有无... 详细信息

针对导管螺旋桨的梢部流动,受压气机中“机匣处理”的启发,将矩形凹槽结构应用于导管内壁,用于降低导管螺旋桨梢涡强度和抑制梢涡空化,进而有望改善导管螺旋桨的水动力和空泡性能。采用计算流体力学方法,针对19A导管和Ka4-70螺旋桨有无凹槽/不同凹槽结构进行非定常数值计算,研究凹槽结构对桨叶叶梢压力、梢涡强度、梢涡结构以及水动力性能的影响。结果表明:凹槽结构会明显改变导管螺旋桨梢部流场涡的形成,减弱梢涡强度,提高叶片梢部最小压力,并且对推进性能几乎没有影响。研究结果可为导管螺旋桨的梢涡控制以及减振降噪提供一种新的解决途径。

关键词：导管螺旋桨凹槽结构梢涡结构空泡机匣处理

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

考虑空间需求不均的模块化公交线路运行方案优化研究

引用

交通运输系统工程与信息 2024年第4期24卷 166-175页

作者：易洪波刘昱岗王童语西南交通大学交通运输与物流学院成都611756 西南交通大学综合交通运输智能化国家地方联合工程实验室成都611756 西南交通大学综合交通大数据应用技术国家工程实验室成都611756 纽约大学阿布扎比分校工程系阿布扎比129188阿拉伯联合酋长国

传统固定容量公交车辆难以应对公交线路上空间分布不均的需求。为解决这一问题,引入模块化公交车辆,通过编组与解编的方式实现车队在运行中的容量动态变化,以更贴合需求在空间上的变化。基于运行时空图重构的方法,建立描述模块化公交线... 详细信息

传统固定容量公交车辆难以应对公交线路上空间分布不均的需求。为解决这一问题,引入模块化公交车辆,通过编组与解编的方式实现车队在运行中的容量动态变化,以更贴合需求在空间上的变化。基于运行时空图重构的方法,建立描述模块化公交线路运行方案的优化模型,所构建模型为混合整数非线性规划(Mixed Integer-Nonlinear Program,MINLP)模型,模型决策变量包括车队的运行方案以及模块化公交单元的运行方案。为方便求解,采用时间离散化手段,通过一系列方法将所构建的MINLP模型转化为易于求解的混合整数线性规划(Mixed Integer-Linear Program,MILP)模型,并基于成都市真实公交线路与乘客需求数据进行案例分析。实验结果表明,与传统容量固定式公交相比,模块化公交的应用能够使乘客成本降低11.44%,运营成本降低31.35%,综合降低20.32%的系统总成本。敏感性分析实验结果分析了系统供给与需求变化对系统成本产生的影响。

关键词：城市交通运行方案优化混合整数非线性优化模型模块化公交时间离散化 Gurobi

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Discrete Element Modelling of Damage Evolution of Concrete Considering Meso-Structure of ITZ

引用

Computer Modeling in Engineering & Sciences 2024年第6期139卷 3495-3511页

作者： Weiliang Gao Shixu Jia Tingting Zhao Zhiyong wang Institute of Defense Engineering Academy of Military SciencesChinese People’s Liberation ArmyBeijing100850China College of Mechanical and Vehicle Engineering Taiyuan University of TechnologyTaiyuan030024China State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China

The mechanical properties of interfacial transition zones(ITZs)have traditionally been simplified by reducing the stiffness of cement in previous simulation methods.A novel approach based on the discrete element method(DEM)has been developed for modeling *** new approach efficiently simulates the meso-structure of ITZs,accurately capturing their heterogeneous *** against established uniaxial compression experiments confirms the precision of *** proposedmodel canmodel the process of damage evolution containing cracks initiation,propagation and *** increasing loads,cracks within ITZs progressively accumulate,culminating in macroscopic fractures that traverse themortarmatrix,forming the complex,serpentine path of *** study reveals four distinct displacement patterns:tensile compliant,tensile opposite,mixed tensile-shear,and shear opposite patterns,each indicative of different stages in concrete’s damage *** widening angle of these patterns delineates the progression of cracks,with the tensile compliant pattern signaling the initial crack appearance and the shear opposite pattern indicating the concrete model’s ultimate failure.

关键词： Discrete element method damage evolution interfacial transition zone meso-structure model

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Physics-informed deep Koopman operator for Lagrangian dynamic systems

引用

Science China(Information Sciences) 2024年第9期67卷 146-163页

作者： Xuefeng wang Yang CAO Shaofeng CHEN Yu KANG Department of Automation University of Science and Technology of China State Key Laboratory of Fire Science University of Science and Technology of China Institute of Advanced Technology University of Science and Technology of China

Accurate mechanical system models are crucial for safe and stable control. Unlike linear systems,Lagrangian systems are highly nonlinear and difficult to optimize because of their unknown system *** research thus used deep neural networks to generate linear models of original systems by mapping nonlinear dynamic systems into a linear space with a Koopman observable function encoder. The controller then relies on the Koopman linear model. However, without physical information constraints, ensuring control consistency between the original nonlinear system and the Koopman system is tough, as the learning process of the Koopman observation function is unsupervised. This paper thus proposes a two-stage learning algorithm that uses structural subnetworks to build a physics-informed network topology to simultaneously learn the Koopman observable functions and the system energy representation. In the Koopman matrix learning session, a quadratic-constrained optimization problem is solved to ensure that the Koopman representation satisfies the energy difference matching hard constraint. The proposed energy-preserving deep Lagrangian Koopman(EPDLK) framework effectively represents the dynamics of the Lagrangian system while ensuring control consistency. The effectiveness of EPDLK is compared with those of various Koopman observable function construction methods in multistep prediction and trajectory tracking tasks. EPDLK achieves better control consistency by guaranteeing energy difference matching, which facilitates the application of the control law generated on the Koopman system directly to the original nonlinear Lagrangian system.

关键词： Koopman operator Lagrangian physics-informed nonlinear model predictive control (MPC)

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

全方位机器人的重心位置预测与轨迹跟踪控制

引用

控制理论与应用 2024年第1期41卷 145-154页

作者：王义娜刘赛男王硕玉杨俊友沈阳工业大学电气工程学院辽宁沈阳110870 高知工科大学智能机械系日本高知7828502

针对全方向移动机器人存在非线性动态强耦合、实时重心偏移及难以实现高精度跟踪控制的问题,本文提出一种基于长短期记忆(LSTM)神经网络的重心位置在线预测的轨迹跟踪控制法.首先,建立考虑重心偏移的动力学模型并基于LSTM神经网络训练... 详细信息

针对全方向移动机器人存在非线性动态强耦合、实时重心偏移及难以实现高精度跟踪控制的问题,本文提出一种基于长短期记忆(LSTM)神经网络的重心位置在线预测的轨迹跟踪控制法.首先,建立考虑重心偏移的动力学模型并基于LSTM神经网络训练构建其对比模型;其次,基于模型对比法实时估计重心偏移参数,再基于张神经网络(ZNN)对估计的重心偏移参数进行预测以减小估计过程引起的滞后;最后,基于非线性动态反馈解耦法设计数值加速度控制算法,且基于离散系统极点配置法分析了系统的稳定性.仿真结果验证了所提方法相对于数值加速度控制器与自适应控制器因能在线预测重心偏移参数完成高精度动态解耦实现控制精度的提高.实际实验中,所提控制算法相比数值加速度控制及模型预测控制,其跟踪精度明显提高,这表明所提控制算法可显著减小重心偏移对跟踪控制精度的影响.

关键词：跟踪控制时变矩阵求逆重心偏移参数估计长短期记忆神经网络

来源：

维普期刊数据库

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

液氮作用下冻结态与融化态煤体力学特征及劣化机理研究

引用

采矿与安全工程学报 2024年第2期41卷 395-406页

作者：秦雷马超李树刚林海飞王平西安科技大学安全科学与工程学院陕西西安710054 西安科技大学西部矿井开采及灾害防治教育部重点实验室陕西西安710054

液氮可通过改变煤层内部结构从而影响煤体力学性能。为研究液氮作用下煤体劣化机理,以冻结态和融化态煤样为研究对象,采用扫描电镜观测煤体内部裂隙形态,通过开展巴西劈裂试验、单轴抗压试验测得其力学特征变化。研究结果表明:单次冻结5... 详细信息

液氮可通过改变煤层内部结构从而影响煤体力学性能。为研究液氮作用下煤体劣化机理,以冻结态和融化态煤样为研究对象,采用扫描电镜观测煤体内部裂隙形态,通过开展巴西劈裂试验、单轴抗压试验测得其力学特征变化。研究结果表明:单次冻结50 min以上,煤体抗拉、单轴抗压强度增加,随着冻结时间增长,煤体强度、弹性模量呈先增后减趋势;冻融循环次数增加,煤体力学性能降低,初期(0~10循环)降幅较大,后趋于平缓;冻融循环造成的煤体损伤更严重,融化态煤样更易形成致密裂隙网格;为评价不同状态煤体冻融损伤,计算相对弹性模量E,拟合冻融次数和相对抗拉强度σs、相对抗压强度σu的关系,随着冻融次数增加,E、σs和σu均在冻融初期大幅下降,后趋于平缓,且融化态煤体后期降低幅度大于冻结态煤体。

关键词：巴西劈裂单轴压缩力学强度脆性破坏破坏应变

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Association of Human Whole-blood NAD+Levels with Nabothian Cyst

引用

Biomedical and Environmental Sciences 2024年第5期37卷 471-478页

作者： XU Ling wang Yue Xuan wang Wei FAN Xue CHEN Xue Yu ZHOU Tian Yun LIU Yu He YU Ye YANG Fan JU Zhen Yu ZHOU Yong wang Deng Liang Clinical Research Institute Shanghai General HospitalShanghai Jiao Tong University School of MedicineShanghai 200080China NHC Key Lab of Reproduction Regulation Shanghai Engineering Research Center of Reproductive Health Drugs and DevicesShanghai Institute for Biomedical and Pharmaceutical TechnologiesShanghai 200237China Department of Applied Statistics Johannes Kepler University LinzLinz 4040Austria Hematology Center Beijing Key Laboratory of Pediatric Hematology OncologyNational Key Discipline of Pediatrics(Capital Medical University)Key Laboratory of Major Diseases in ChildrenMinistry of EducationBeijing Children's HospitalCapital Medical UniversityNational Center for Children's HealthBeijing 100045China Department of Biostatistics School of Public HealthCheeloo College of MedicineShandong UniversityJinan 250012ShandongChina Clinical Medicine School of Basic MedicineShanghai Medical College Fudan UniversityShanghai 200032China Department of Biochemistry and Molecular Biology Hengyang Medical SchoolUniversity of South ChinaHengyang 421001HunanChina Administrative Office Total Quality Management OfficeTotal Quality Management InstituteShanghai General HospitalShanghai Jiao Tong University School of MedicineShanghai 200080China The First Affiliated Hospital of Jinan University Institute of Aging and Regenerative MedicineJinan UniversityJinan 510632GuangzhouChina Department of Scientific Research The First Affiliated Hospital of Huzhou UniversityHuzhou 313000ZhejiangChina Department of Neurosurgery Neurosurgery Research InstituteThe First Affiliated HospitalFujian Medical UniversityFuzhou 350005FujianChina Department of Neurosurgery Binhai Branch of National Regional Medical CenterThe First Affiliated HospitalFujian Medical UniversityFuzhou 350209FujianChina Fujian Provincial Institutes of Brain Disorders and Brain Sciences The First Affiliated HospitalFujian Medical UniversityFuzhou 350005FujianChina Fujian Provincial Clinical Research Center for Neurological

Objective Little is known about the association between whole-blood nicotinamide adenine dinucleotide(NAD^(+))levels and nabothian *** study aimed to assess the association between NAD^(+)levels and nabothian cysts in healthy Chinese *** Multivariate logistic regression analysis was performed to analyze the association between NAD^(+)levels and nabothian *** The mean age was 43.0±11.5 years,and the mean level of NAD^(+)was 31.3±5.3μmol/*** cysts occurred in 184(27.7%)participants,with single and multiple cysts in 100(15.0%)and84(12.6%)participants,*** total nabothian cyst prevalence gradually decreased from37.4%to 21.6%from Q1 to Q4 of NAD^(+)and the prevalence of single and multiple nabothian cysts also decreased across the NAD^(+)*** compared with the highest NAD^(+)quartile(≥34.4μmol/L),the adjusted odds ratios with 95%confidence interval of the NAD^(+)Q1 was 1.89(1.14–3.14)for total nabothian *** risk of total and single nabothian cysts linearly decreased with increasing NAD^(+)levels,while the risk of multiple nabothian cysts decreased more rapidly at NAD^(+)levels of 28.0 to35.0μmol/***:Low NAD^(+)levels were associated with an increased risk of total and multiple nabothian cysts.

关键词： Nicotinamide adenine dinucleotide Nabothian cyst Female Risk factor

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Attribute Reduction of Hybrid Decision Information Systems Based on Fuzzy Conditional Information Entropy

引用

Computers, Materials & Continua 2024年第5期79卷 2063-2083页

作者： Xiaoqin Ma Jun wang Wenchang Yu Qinli Zhang School of Big Data and Artificial Intelligence Chizhou UniversityChizhou247000China Anhui Education Big Data Intelligent Perception and Application Engineering Research Center Chizhou247000China

The presence of numerous uncertainties in hybrid decision information systems(HDISs)renders attribute reduction a formidable *** available attribute reduction algorithms,including those based on Pawlak attribute importance,Skowron discernibility matrix,and information entropy,struggle to effectively manages multiple uncertainties simultaneously in HDISs like the precise measurement of disparities between nominal attribute values,and attributes with fuzzy boundaries and abnormal *** order to address the aforementioned issues,this paper delves into the study of attribute reduction *** of all,a novel metric based on the decision attribute is introduced to solve the problem of accurately measuring the differences between nominal attribute *** newly introduced distance metric has been christened the supervised distance that can effectively quantify the differences between the nominal attribute ***,based on the newly developed metric,a novel fuzzy relationship is defined from the perspective of“feedback on parity of attribute values to attribute sets”.This new fuzzy relationship serves as a valuable tool in addressing the challenges posed by abnormal attribute ***,leveraging the newly introduced fuzzy relationship,the fuzzy conditional information entropy is defined as a solution to the challenges posed by fuzzy *** effectively quantifies the uncertainty associated with fuzzy attribute values,thereby providing a robust framework for handling fuzzy information in hybrid information ***,an algorithm for attribute reduction utilizing the fuzzy conditional information entropy is *** experimental results on 12 datasets show that the average reduction rate of our algorithm reaches 84.04%,and the classification accuracy is improved by 3.91%compared to the original dataset,and by an average of 11.25%compared to the other 9 state-of-the-art reduction *** comprehensive analysis o

关键词： Hybrid decision information systems fuzzy conditional information entropy attribute reduction fuzzy relationship rough set theory(RST)

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：