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Adaptive robust neural control of a two-manipulator system holding a rigid object with inaccurate base frame parameters

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Frontiers of Information Technology & Electronic Engineering 2018年第11期19卷 1316-1327页

作者： Fan XU Jin WANG guo-dong lu State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang University

The problem of self-tuning control with a two-manipulator system holding a rigid object in the presence of inaccurate translational base frame parameters is addressed. An adaptive robust neural controller is proposed to cope with inaccurate translational base frame parameters, internal force, modeling uncertainties, joint friction, and external disturbances. A radial basis function neural network is adopted for all kinds of dynamical estimation, including undesired internal force. To validate the effectiveness of the proposed approach, together with simulation studies and analysis, the position tracking errors are shown to asymptotically converge to zero, and the internal force can be maintained in a steady range. Using an adaptive engine, this approach permits accurate online calibration of the relative translational base frame parameters of the involved manipulators. Specialized robust compensation is established for global stability. Using a Lyapunov approach, the controller is proved robust in the face of inaccurate base frame parameters and the aforementioned uncertainties.

关键词： Cooperative manipulators Neural networks Inaccurate translational base frame Adaptive control Robust control

Conflict detection and resolution for authorization policies in workflow systems

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第8期10卷 1082-1092页

作者： Chen-hua MA guo-dong lu Jiong QIU Engineering & Computer Graphics Institute Zhejiang University Hangzhou 310027 China Department of Computer Engineering Hangzhou Dianzi University Hangzhou 310008 China

The specification of authorization policies in access control models proposed so far cannot satisfy the requirements in workflow management systems(WFMSs).Furthermore,existing approaches have not provided effective conflict detection and resolution methods to maintain the consistency of authorization polices in *** address these concerns,we propose the definition of authorization policies in which context constraints are considered and the complicated requirements in WFMSs can be *** on the definition,we put forward static and dynamic conflict detection methods for authorization *** defining two new concepts,the precedence establishment rule and the conflict resolution policy,we provide a flexible approach to resolving conflicts.

关键词： Workflow management system (WFMS) Authorization policy Conflict detection and resolution

Numerical investigation of the influence of companion drops on drop-on-demand ink jetting

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2012年第8期13卷 584-595页

作者： Hai-yun ZHANG Jin WANG guo-dong lu Institution of Engineering and Computer Graphics Zhejiang UniversityHangzhou 310027China

In this study we characterized and investigated the specific phenomenon of "companion drops" in the drop-ondemand(DOD) ink jetting process.A series of simulations based on a piezoelectric DOD printhead system is presented,adapting the volume-of-fluid(VOF) interface-capturing method to track the boundary evolution and model the interfacial *** results illustrate the causality between the generation of companion drops and droplet deviation behavior,as well as their close correlations with ink jetting straightness and printing *** characteristics of companion drops are summarized and compared with those of satellite ***,a theoretical mechanism for the generation of companion drops is presented,and their effects and behaviors are analyzed and ***,the effects of critical factors on the generation of companion drops are investigated and characterized based on variations in the printable pressure *** are given for the suppression of companion drops and for the improvement of printing accuracy.

关键词： Drop-on-demand (DOD) ink jetting Droplet deviation Companion drops Computational fluid dynamics (CFD) Volume-of-fluid (VOF) method

Numerical simulation and optimization design of the EGR cooler in vehicle

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第9期9卷 1270-1276页

作者： Yu-qi HUANG Xiao-li YU guo-dong lu Power Machinery and Vehicular Engineering Institute Zhejiang University Hangzhou 310027 China Zhejiang Yinlun Machinery Co. Ltd. Tiantai 317200 China

The EGR (exhaust gas recirculation) technique can greatly reduce the NOx emission of diesel engines, especially when an EGR cooler is employed. Numerical simulations are applied to study the flow field and temperature distributions inside the EGR cooler. Three different models of EGR cooler are investigated, among which model A is a traditional one, and models B and C are improved by adding a helical baffle in the cooling area. In models B and C the entry directions of cooling water are different, which mostly influences the flow resistance. The results show that the improved structures not only lengthen the flow path of the cooling water, but also enhance the heat exchange rate between the cool and hot media. In conclusion we suggest that the improved structures are more powerful than the traditional one.

关键词： Exhaust gas recirculation (EGR) cooler Computational fluid dynamics (CFD) Shell-and-tube heat exchanger Helical baffle

Energy Consumption in Comminution of Mica with Cavitation Abrasive Water Jet

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Journal of China University of Mining and Technology 2007年第2期17卷 251-254页

作者： guo Chu-wen dong lu College of Mechanical ＆ Electrical Engineering China University of Mining ＆ Technology Xuzhou Jiangsu 221008 China

We have studied the efficiency of energy consumption in the comminution of mica powder with cavitation abrasive water jet technology. The energy required to create new surfaces in the comminution of mica powder with cavitation abrasive water jet was calculated,in order to estimate its efficiency of energy consumption. The particle size distribution and the specific surface area were measured by applying a JEM-200CX transmission electron microscope and an Autosorb-1 automatic surface area analyzer. The study results show that the efficiency of energy consumed in creating new surface areas is as high as 2.92%,or 4.94% with the aid of cavitation in the comminution of mica powder. This efficiency will decrease with an increase in the number of comminutions. After three comminutions,the efficien-cies will become 1.91% and 2.29% for comminution without cavitation and with cavitation,respectively. The abrasive water jet technology is an effective way for comminution of mica powder.

关键词： energy consumption comminution mica cavitation abrasive water jet

An authorization model for collaborative access control

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Journal of Zhejiang University-Science C(Computers and Electronics) 2010年第9期11卷 699-717页

作者： Chen-hua MA guo-dong lu Jiong QIU Engineering and Computer Graphics Institute Zhejiang University Hangzhou 310027 China Department of Computer Science and Technology Hangzhou Dianzi University Hangzhou 310018 China

Collaborative access control is receiving growing attention in both military and commercial areas due to an urgent need to protect confidential resources and sensitive *** access control means that multiple subjects should participate to make access control decisions to prevent fraud or the abuse of *** approaches to access control cannot satisfy the requirements of collaborative access *** address this concern,we propose an authorization model for collaborative access *** central notions of the model are collaborative permission,collaboration constraint,and collaborative authorization policy,which make it possible to define the collaboration among multiple subjects involved in gaining a *** implementation architecture of the model is also ***,we present effective conflict detection and resolution methods for maintaining the consistency of collaborative authorization policies.

关键词： Collaborative access control Collaborative permission Conflict detection and resolution

A study of multi-pass scheduling methods for die-less spinning

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2017年第6期18卷 413-429页

作者： Hai guo Jin WANG guo-dong lu Zi-han SANG Qi-hang WANG State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang University Hangzhou 310027 China

The multi-pass scheduling method is a key issue in die-less spinning for determining the quality of the final products, including their shape deviations and wall thicknesses, and has drawn increasing interest in recent studies devoted to trying to improve the accuracy of the formed parts. In this paper, two main parameters, roller path profiles and deformation allocations in each pass, are considered in newly proposed multi-pass scheduling and optimizing methods in die-less spinning. Four processing methods with different roller path profiles and with three deformation allocation methods are proposed for investigating the influence of scheduling parameters on product qualities. The ＇similar geometry principle for restraining shape deviation＇ and the ＇small curvature principle for maintaining wall thickness＇ are presented for optimal design of roller path profiles; in addition, the ＇uniform allocation principle for maintaining wall thickness＇ and the ＇large deformation principle for restraining shape deviation＇ are brought forward as suggestions for deformation allocations. Based on these principles, a scheduling method denoted by RF＋（FP ＆ EHS） is presented to improve the comprehensive quality of a product of die-less spinning.

关键词： Die-less spinning Pass schedules Shape deviations Roller path profiles Deformation allocations

Sketch based garment modeling on an arbitrary view of a 3D virtual human model

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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第3期12卷 195-203页

作者： Yu-lei GENG Jin WANG guo-dong lu Zheng LIU Gang CHEN State Key Lab of CAD & CG Zhejiang University Hangzhou 310027 China Department of Garment Jiaxing University Jiaxing 314000 China Department of Mechanical Engineering Zhejiang Textile and Fashion College Ningbo 315211 China

This paper presents a new approach for modeling a virtual garment intuitively and simply by sketching garment style *** user sketches directly onto the surface of 3D virtual human from arbitrary viewing directions,and the 3D garment suited to the virtual human can be created ***,a distance field based allocation algorithm is proposed to find the 3D point which has the shortest given distance to the virtual human along the view ***,the 3D style lines are generated by transforming from the 2D strokes on the human model and all the garment pieces are recognized from the 3D style ***,the 3D garment model is constructed by using the angle and offset based interpolation and Delaunay *** addition,we propose a body feature based template reusing method to fit the 3D garment to different virtual human *** method can be adapted to designer habits and improve the usefulness of garment *** show that the method is useful and efficient.

关键词： Sketch-based interfaces 3D garment modeling Distance field Garment style template

Weighted Composition Operators That Preserve Frames On Weighted Hardy Spaces

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Acta Mathematica Sinica,English Series 2024年第7期40卷 1645-1654页

作者： Ya Li dong Rui Liu guo Xiang lu School of Mathematical Sciences and LPMC Nankai UniversityTianjin300071P.R.China School of Statistics and Mathematics Zhongnan University of Economics and LawWuhan430073P.R.China

In this paper, we characterize weighted composition operators that preserve frames on the weighted Hardy spaces in the unit disk. In particular, we obtain the symbol properties of the bounded invertible weighted composition operators. Moreover, we establish the equivalence between bounded invertible operators and frame-preserving operators. Furthermore, we show that weighted composition operator preserves frames if and only if it preserves the Riesz bases property. Additionally,we investigate the weighted composition operators that preserve tight or normalized tight frames on the Dirichlet space.

关键词： Weighted composition operators Weighted Hardy spaces frames invertible

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