期刊文献+
共找到2,308篇文章
< 1 2 116 >
每页显示 20 50 100
Augmented Industrial Data-Driven Modeling Under the Curse of Dimensionality
1
作者 Xiaoyu Jiang Xiangyin Kong Zhiqiang Ge 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2023年第6期1445-1461,共17页
The curse of dimensionality refers to the problem o increased sparsity and computational complexity when dealing with high-dimensional data.In recent years,the types and vari ables of industrial data have increased si... The curse of dimensionality refers to the problem o increased sparsity and computational complexity when dealing with high-dimensional data.In recent years,the types and vari ables of industrial data have increased significantly,making data driven models more challenging to develop.To address this prob lem,data augmentation technology has been introduced as an effective tool to solve the sparsity problem of high-dimensiona industrial data.This paper systematically explores and discusses the necessity,feasibility,and effectiveness of augmented indus trial data-driven modeling in the context of the curse of dimen sionality and virtual big data.Then,the process of data augmen tation modeling is analyzed,and the concept of data boosting augmentation is proposed.The data boosting augmentation involves designing the reliability weight and actual-virtual weigh functions,and developing a double weighted partial least squares model to optimize the three stages of data generation,data fusion and modeling.This approach significantly improves the inter pretability,effectiveness,and practicality of data augmentation in the industrial modeling.Finally,the proposed method is verified using practical examples of fault diagnosis systems and virtua measurement systems in the industry.The results demonstrate the effectiveness of the proposed approach in improving the accu racy and robustness of data-driven models,making them more suitable for real-world industrial applications. 展开更多
关键词 Index Terms—Curse of dimensionality data augmentation data-driven modeling industrial processes machine learning
下载PDF
Effect of Processing Conditions on the Compression Elasticity of Three Dimensional Crimp Staple
2
作者 庄毅 王华平 +1 位作者 王彪 张玉梅 《Journal of China Textile University(English Edition)》 EI CAS 2000年第3期12-15,共4页
The multi-hollow three dimensional(3-D)crimp sta-ple were prepared by the non-symmetrical cooling spin-ning technology.The material properties,spinneret shape,drawing conditions,heat-setting conditions and silicon fin... The multi-hollow three dimensional(3-D)crimp sta-ple were prepared by the non-symmetrical cooling spin-ning technology.The material properties,spinneret shape,drawing conditions,heat-setting conditions and silicon finishing conditions that influence the compression elasticity of the staple have been investigated.It is found that the compression elasticity of 3-D crimp PET staple is larger than that of 3-D crimp PP staple.The com-pression elasticity of the 5-hollow staple is much 展开更多
关键词 THREE dimensional CRIMP STAPLE compression ELASTICITY processING conditions.
下载PDF
Analysis and evaluation of effects of processing steps on dimensional tolerance of PIM parts
3
作者 LI Yi-min LOU Jia YUE Jian-ling 《Journal of Central South University of Technology》 2005年第z1期33-38,共6页
The factors affecting the dimensional tolerance of powder injection molding (PIM), such as the selection of the powder and binder, the feedstock homogeneity, the feedstock thermal properties, the feedstock rheologic b... The factors affecting the dimensional tolerance of powder injection molding (PIM), such as the selection of the powder and binder, the feedstock homogeneity, the feedstock thermal properties, the feedstock rheologic behavior, the debinding schedule and atmosphere and sintering temperature gradient were discussed. An attempt was made to develop a model to estimate the influence of important variables. The results show that a better understanding of these factors can provide some useful theoretical instructions for large scale production. 展开更多
关键词 powder injection MOLDING dimensional TOLERANCE processING step
下载PDF
SMALL DENSITY FLUCTUTAION FOR ONE DIMENSIONAL CONTACT PROCESSES UNDER NONEQUILIBRIUM
4
作者 陈金文 《Acta Mathematica Scientia》 SCIE CSCD 1993年第4期399-405,共7页
This paper shows that for a supercritical contact process in one dimension, if the initial distribution satisfies reasonable hypothesis, then the first hitting time of certain set with anomalous small density is asymp... This paper shows that for a supercritical contact process in one dimension, if the initial distribution satisfies reasonable hypothesis, then the first hitting time of certain set with anomalous small density is asymptotically exponentially distributed. We also show the similar result for the contact process on the finite set [0, N]. 展开更多
关键词 SMALL DENSITY FLUCTUTAION FOR ONE dimensional CONTACT processES UNDER NONEQUILIBRIUM Za 带刀 TH
下载PDF
Simulation-Based Construction of Three-Dimensional Process Model for Punching Cartridge Cases 被引量:1
5
作者 Zhifang Wei Yechang Hu +1 位作者 Wu Lyu Jianzhong Gao 《Journal of Beijing Institute of Technology》 EI CAS 2018年第2期276-284,共9页
A method of constructing three-dimensional process model for the punching cartridge cases is presented based on DEFORM simulation analysis. Using DEFORM software,the finite element simulation models for the punching a... A method of constructing three-dimensional process model for the punching cartridge cases is presented based on DEFORM simulation analysis. Using DEFORM software,the finite element simulation models for the punching and forming process of cartridge cases are established,and the corresponding simulation result model of each intermediate procedure is obtained by continuously performing the forming process simulation. The simulation model cannot annotate size and process information due to poor interface between DEFORM software and CAD software. Thus,a 3D annotation module is developed with secondary development technology of UG NX software. Consequently,the final process model with dimension and process information is obtained. Then,with the current 3D process management system,the 3D punching and forming process design of cartridge cases can be completed further. An example is also provided to illustrate that the relative error between the simulation process model and the physical model is less than 2%,which proves the validity and reliability of the proposed method in this study. 展开更多
关键词 punching three-dimensional process model finite element simulation three-dimensional annotation
下载PDF
Description and reconstruction of one-dimensional photonic crystal by digital signal processing theory
6
作者 张娟 付文鹏 +1 位作者 张荣军 王阳 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第10期200-204,共5页
A method of describing one-dimensional photonic crystals (1DPCs) based on Z-domain digital signal processing theory is presented. The analytical expression of the target band gap spectrum in the digital domain is ob... A method of describing one-dimensional photonic crystals (1DPCs) based on Z-domain digital signal processing theory is presented. The analytical expression of the target band gap spectrum in the digital domain is obtained by the autocorrelation of its impulse response. The feasibility of this method is verified by reconstructing two simple 1DPC structures with a target photonic band gap obtained by the traditional transfer matrix method. This method provides an effective approach to function-guided designs of interference-based band gap structures for photonic applications. 展开更多
关键词 one-dimensional photonic crystal digital signal processing Z-TRANSFORM
下载PDF
COMPUTER SIMULATION OF 3-DIMENSIONAL DYNAMIC ASSEMBLY PROCESS OF MECHANICAL ROTATIONAL BODY
7
作者 Yang, Jichang Li, Jinban +1 位作者 Gu, Jinan Zhang, Ziyu 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 1998年第3期8-12,共5页
Focusing on the study of the components of mechanical rotational body,the data structure and algorithm of component model generation are discussed.Some problems in assembly process of 3 dimensional graph of component... Focusing on the study of the components of mechanical rotational body,the data structure and algorithm of component model generation are discussed.Some problems in assembly process of 3 dimensional graph of components are studied in great detail. 展开更多
关键词 Mechanical component Component mode Assembly process 3 dimensional graph Dynamic model
全文增补中
Locating Error Considering Dimensional Errors Modeling for Multistation Manufacturing System 被引量:2
8
作者 ZHANG Faping LU Jiping TANG Shuiyuan SUN Houfang JIAO Li 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2010年第6期765-773,共9页
Multistation machining process is widely applied in contemporary manufacturing environment. Modeling of variation propagation in multistation machining process is one of the most important research scenarios. Due to t... Multistation machining process is widely applied in contemporary manufacturing environment. Modeling of variation propagation in multistation machining process is one of the most important research scenarios. Due to the existence of multiple variation streams, it is challenging to model and analyze variation propagation in a multi-station system. Current approaches to error modeling for multistation machining process are not explicit enough for error control and ensuring final product quality. In this paper, a mathematic model to depict the part dimensional variation of the complex multistation manufacturing process is formulated. A linear state space dimensional error propagation equation is established through kinematics analysis of the influence of locating parameter variations and locating datum variations on dimensional errors, so the dimensional error accumulation and transformation within the multistation process are quantitatively described. A systematic procedure to build the model is presented, which enhances the way to determine the variation sources in complex machining systems. A simple two-dimensional example is used to illustrate the proposed procedures. Finally, an industrial case of multistation machining part in a manufacturing shop is given to testify the validation and practicability of the method. The proposed analytical model is essential to quality control and improvement for multistation systems in machining quality forecasting and design optimization. 展开更多
关键词 multistation manufacturing process error propagation dimensional errors state space model
下载PDF
UNIFORM PACKING DIMENSION RESULTS FOR MULTIPARAMETER STABLE PROCESSES 被引量:3
9
作者 钟玉泉 胡迪鹤 《Acta Mathematica Scientia》 SCIE CSCD 2007年第1期1-10,共10页
In this article, authors discuss the problem of uniform packing dimension of the image set of multiparameter stochastic processes without random uniform Holder condition, and obtain the uniform packing dimension of mu... In this article, authors discuss the problem of uniform packing dimension of the image set of multiparameter stochastic processes without random uniform Holder condition, and obtain the uniform packing dimension of multiparameter stable processes. If Z is a stable (N, d, α)-process and αN ≤ d, then the following holds with probability 1 Dim Z(E)=α Dim E for any Borel setE ∈B(R +^N), where Z(E)={x:E←t∈E,Z(t)=x}, Dim (E) denotes the packing dimension of E. 展开更多
关键词 (N d α)-stable process stopping time Kolmogorov upper index packing dimension
下载PDF
Approach to Power Spectrum Density Values in Three Dimensional Acceleration of Ground Motions
10
作者 Luo, Chuanxin Zhu, Ke Zhang, Lifu 《China Ocean Engineering》 SCIE EI 1993年第4期417-424,共8页
In this paper, based on the random characteristic analysis of Tianjin Hospital earthquake waves of Tangshan aftershock, the three dimensional acceleration power spectrum density ratio has been presented.
关键词 ACCELERATION CALCULATIONS Earthquake resistance EARTHQUAKES Ocean engineering Offshore structures Random processes Seismic waves Structural analysis Three dimensional White noise
下载PDF
DIMENSION RESULTS FORORNSTEIN-UHLENBECK TYPE MARKOVPROCESS
11
作者 邓爱姣 刘禄勤 《Acta Mathematica Scientia》 SCIE CSCD 1999年第4期417-424,共8页
Let {X-t, t greater than or equal to 0} be an Ornstein-Uhlenbeck type Markov process with Levy process A(t), the authors consider the fractal properties of its ranges, give the upper and lower bounds of the Hausdorff ... Let {X-t, t greater than or equal to 0} be an Ornstein-Uhlenbeck type Markov process with Levy process A(t), the authors consider the fractal properties of its ranges, give the upper and lower bounds of the Hausdorff dimensions of the ranges and the estimate of the dimensions of the level sets for the process. The existence of local times and occupation times of X-t are considered in some special situations. 展开更多
关键词 Levy process Ornstein-Uhlenbeck type Markov process RANGE level set Hausdorff dimension local time occuption time
下载PDF
Two-dimensional numerical research on effects of titanium target bombarded by TEMPⅡ accelerator 被引量:1
12
作者 吴迪 宫野 +3 位作者 刘金远 王晓钢 刘悦 马腾才 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第11期2682-2687,共6页
Two-dimensional numerical research has been carried out on the ablation effects of titanium target irradiated by intense pulsed ion beam (IPIB) generated by TEMP Ⅱ accelerator. Temporal and spatial evolution of the... Two-dimensional numerical research has been carried out on the ablation effects of titanium target irradiated by intense pulsed ion beam (IPIB) generated by TEMP Ⅱ accelerator. Temporal and spatial evolution of the ablation process of the target during a pulse time has been simulated. We have come to the conclusion that the melting and evaporating process begin from the surface and the target is ablated layer by layer when the target is irradiated by the IPIB. Meanwhile, we also obtained the result that the average ablation velocity in target central region is about 10 m/s, which is far less than the ejection velocity of the plume plasma formed by irradiation. Different effects have been compared to the different ratio of the ions and different energy density of IPIB while the target is irradiated by pulsed beams. 展开更多
关键词 intense pulsed ion beam two-dimensional numerical model ablation process TITANIUM
下载PDF
Numerical simulation research of dimension variation in heavy plate during quenching and tempering process
13
作者 ZHANG Qingfeng JIANG Hongsheng 《Baosteel Technical Research》 CAS 2012年第4期47-50,共4页
The dimension variation of B610E steel during the quenching and tempering process was simulated by ABAQUS,the coefficient of heat transfer during quenching was verified by the buried thermocouple test and the trend of... The dimension variation of B610E steel during the quenching and tempering process was simulated by ABAQUS,the coefficient of heat transfer during quenching was verified by the buried thermocouple test and the trend of the dimension variation during the quenching process was also calculated by ABAQUS. It was shown by the comparison of simulated results and industrially measured results that only the simulation of thickness and width variation was accurate, while length variation needed further simulation. Besides, the dimension variation trend was identical with the measured results. 展开更多
关键词 heavy plate quenching and tempering process dimension variation numerical simulation
下载PDF
Numerical Approximation of Fractal Dimension of Gaussian Stochastic Processes
14
作者 Freddy H. Marin Sanchez William Eduardo Alfonso 《Applied Mathematics》 2014年第12期1763-1772,共10页
In this paper we propose a numerical method to estimate the fractal dimension of stationary Gaussian stochastic processes using the random Euler numerical scheme and based on an analytical formulation of the fractal d... In this paper we propose a numerical method to estimate the fractal dimension of stationary Gaussian stochastic processes using the random Euler numerical scheme and based on an analytical formulation of the fractal dimension for filtered stochastic signals. The discretization of continuous time processes through this random scheme allows us to find, numerically, the expected value, variance and correlation functions at any point of time. This alternative method for estimating the fractal dimension is easy to implement and requires no sophisticated routines. We use simulated data sets for stationary processes of the type Random Ornstein Uhlenbeck to graphically illustrate the results and compare them with those obtained whit the box counting theorem. 展开更多
关键词 STATIONARY GAUSSIAN Stochastic processes FRACTAL dimension RANDOM EULER Numerical Scheme
下载PDF
Hausdorff dimension of set generated by exceptional oscillations of a class of N-parameter Ganssian processes
15
作者 林正炎 程宗毛 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2007年第2期237-245,共9页
A class of N-parameter Gaussian processes are introduced, which are more general than the N-parameter Wiener process. The definition of the set generated by exceptional oscillations of a class of these processes is gi... A class of N-parameter Gaussian processes are introduced, which are more general than the N-parameter Wiener process. The definition of the set generated by exceptional oscillations of a class of these processes is given, and then the Hausdorff dimension of this set is defined. The Hausdorff dimensions of these processes are studied and an exact representative for them is given, which is similar to that for the two-parameter Wiener process by Zacharie (2001). Moreover, the time set considered is a hyperrectangle which is more general than a hyper-scluare used by Zacharie (2001). For this more general case, a Fernique-type inequality is established and then using this inequality and the Slepian lemma, a Levy's continuity modulus theorem is shown. Independence of increments is required for showing the representative of the Hausdorff dimension by Zacharie (2001). This property is absent for the processes introduced here, so we have to find a different way. 展开更多
关键词 N-parameter Gaussian process modulus of continuityl Hausdorff dimension
下载PDF
Comprehensive two-dimensional river ice model based on boundary-fitted coordinate transformation method 被引量:1
16
作者 Ze-yu MAO Jing YUAN +2 位作者 Jun BAO Xiao-fan PENG Guo-qiang TANG 《Water Science and Engineering》 EI CAS CSCD 2014年第1期90-105,共16页
River ice is a natural phenomenon in cold regions, influenced by meteorology, geomorphology, and hydraulic conditions. River ice processes involve complex interactions between hydrodynamic, mechanical, and thermal pro... River ice is a natural phenomenon in cold regions, influenced by meteorology, geomorphology, and hydraulic conditions. River ice processes involve complex interactions between hydrodynamic, mechanical, and thermal processes, and they are also influenced by weather and hydrologic conditions. Because natural rivers are serpentine, with bends, narrows, and straight reaches, the commonly-used one-dimensional river ice models and two-dimensional models based on the rectangular Cartesian coordinates are incapable of simulating the physical phenomena accurately. In order to accurately simulate the complicated river geometry and overcome the difficulties of numerical simulation resulting from both complex boundaries and differences between length and width scales, a two-dimensional river ice numerical model based on a boundary-fitted coordinate transformation method was developed. The presented model considers the influence of the frazil ice accumulation under ice cover and the shape of the leading edge of ice cover during the freezing process. The model is capable of determining the velocity field, the distribution of water temperature, the concentration distribution of frazil ice, the transport of floating ice, the progression, stability, and thawing of ice cover, and the transport, accumulation, and erosion of ice under ice cover. A MacCormack scheme was used to solve the equations numerically. The model was validated with field observations from the Hequ Reach of the Yellow River. Comparison of simulation results with field data indicates that the model is capable of simulating the river ice process with high accuracy. 展开更多
关键词 two-dimensional river ice numerical model boundary-fitted coordinate technology river ice process freeze-up MacCormack scheme natural river
下载PDF
Reconstruction of three-dimensional grain structure in polycrystalline iron via an interactive segmentation method
17
作者 Min-nan Feng Yu-cong Wang +2 位作者 Hao Wang Guo-quan Liu Wei-hua Xue 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2017年第3期257-263,共7页
Using a total of 297 segmented sections, we reconstructed the three-dimensional (3D) structure of pure iron and obtained the largest dataset of 16254 3D complete grains reported to date. The mean values of equivalent ... Using a total of 297 segmented sections, we reconstructed the three-dimensional (3D) structure of pure iron and obtained the largest dataset of 16254 3D complete grains reported to date. The mean values of equivalent sphere radius and face number of pure iron were observed to be consistent with those of Monte Carlo simulated grains, phase-field simulated grains, Ti-alloy grains, and Ni-based super alloy grains. In this work, by finding a balance between automatic methods and manual refinement, we developed an interactive segmentation method to segment serial sections accurately in the reconstruction of the 3D microstructure; this approach can save time as well as substantially eliminate errors. The segmentation process comprises four operations: image preprocessing, breakpoint detection based on mathematical morphology analysis, optimized automatic connection of the breakpoints, and manual refinement by artificial evaluation. © 2017, University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg. 展开更多
关键词 Grain boundaries Image segmentation IRON Mathematical morphology Titanium alloys
下载PDF
Combining cellular automata and Monte Carlo algorithm to simulate three-dimensional grain growth
18
作者 WANG Wei CHEN Ju-hua +1 位作者 GUO Pei-quan ZHAO Ping 《中国有色金属学会会刊:英文版》 CSCD 2006年第A02期104-106,共3页
关键词 晶粒生长 三维模拟 细胞自动机 蒙特卡洛算法 显微结构
下载PDF
Analysis of the Manufactured Tolerances with the Three-Dimensional Method of Angular Chains of Dimensions Applied to a Cylinder Head of Car Engine
19
作者 Aida Mezghani Alain Bellacicco +2 位作者 Jamel Louati Alain Rivière Mohamed Haddar 《Engineering(科研)》 2010年第10期771-779,共9页
This paper proposes an analysis method of the manufactured tolerances applied to a cylinder head of car engine. This method allows to determine the manufacturing tolerances in the case of angular chains of dimensions ... This paper proposes an analysis method of the manufactured tolerances applied to a cylinder head of car engine. This method allows to determine the manufacturing tolerances in the case of angular chains of dimensions and to check its correspondence with the functional tolerances. The objective of this work is to analyze two parameterized functions: the angular defect Δα and the projected length lg of the toleranced surface. The angular defects are determined from the precision of the machine tools, we consider only the geometrical defects (position and orientation of surfaces), making the assumption that the form defects are negligible. The manufactured defect is determined from these two parameterized functions. Then it will be compared with the functional condition in order to check if the selected machining range allows, at end of the manufacturing process, to give a suitable part. 展开更多
关键词 Three-dimensional TOLERANCING Manufacturing process Toleranced Surface ANGULAR DEFECT
下载PDF
MULTI-DIMENSIONAL MARKOV CHAIN–BASED ANALYSIS OF CONFLICT PROBABILITY FOR SPECTRUM RESOURCE SHARING
20
作者 张轶 喻莉 张利维 《Acta Mathematica Scientia》 SCIE CSCD 2015年第1期207-215,共9页
In this paper, we consider the optimal problem of channels sharing with het-erogeneous traffic (real-time service and non-real-time service) to reduce the data conflict probability of users. Moreover, a multi-dimens... In this paper, we consider the optimal problem of channels sharing with het-erogeneous traffic (real-time service and non-real-time service) to reduce the data conflict probability of users. Moreover, a multi-dimensional Markov chain model is developed to analyze the performance of the proposed scheme. Meanwhile, performance metrics are derived. Numerical results show that the proposed scheme can effectively reduce the forced termination probability, blocking probability and spectrum utilization. 展开更多
关键词 multi-dimensional Markov chain model independent Poisson process negative exponential distribution forced termination probability blocking probability
下载PDF
上一页 1 2 116 下一页 到第
使用帮助 返回顶部