Robust envelope-constrained filter with orthonormal bases and semi-definite and semi-infinite programming

In this paper, the equivalence relation between a semi-infinite quadratically constrained convex quadratic programming problem and a combined semi-definite and semi-infinite programming problem is considered. Then, an efficient and reliable discretization algorithm for solving a general class of combined semi-definite and semi-infinite programming problems is developed. Both the continuous-time envelope-constrained optimal equalization filter and the corresponding robust envelope-constrained filter for a communication channel are solved by using the proposed algorithm. This research was partially supported by the Research Committee of The Hong Kong Polytechnic University and the National Natural Science Foundation of China (Grant numbers: 60574073 and 10471142).     

Behavioural representation and simulation of design concepts for systematic conceptual design of mechatronic systems using Petri Nets

The systematic representation of design concepts is an important requirement for computational support during the conceptual design stage within the process of product development. Behavioural simulation of design concepts is used as a systematic representation framework, and behavioural representation is based on modelling and simulating the behaviour of a design artefact at the conceptual level to perform an overall function, leading to behaviour-based conceptual design. The behaviour-based conceptual design approach is critical for mechatronic systems since they require synergistic integration starting from the initial conceptual design phase. The present study is focused on behavioural representation and simulation of design concepts via discrete event system specification formalism and Petri Nets so as to contribute to systematic conceptual design in mechatronic systems. The paper introduces a representation framework for the behaviour-based conceptual design of mechatronic systems and its implementation on five selected case studies, among laboratory-level educational robots. In addition to Petri Net modelling and computer simulations, the implementation also includes physical simulations of the intended operational behaviours for educational robots on a distributed physical structure called the ‘desktop design model’. In this paper, implementation on one of these case studies, namely the ‘frog robot’, is presented in detail.     

The Sound Radiation Characteristic from Un-baffled Rectangular Plates

The sound radiation characteristic from un-baffled rectangular plates is studied in this paper. Both the pressure jump and the transverse displacement of vibrating rectangular plates are also presented. The sound power level radiated from un-baffled plates is numerically calculated by using a double layer integral representation of the sound radiation pressure and the modal coupling coefficients. Rectangular plates with clamped support and elastically support encountered frequently are calculated as numerical experiments. The sound power level radiated from baffled rectangular plates with the same boundary conditions are also calculated in numerical experiments for comparison. From the viewpoint of energy, average velocity square of un-baffled and baffled rectangular plates with␣different boundary conditions is also calculated respectively. The relationship of sound radiation efficiency between un-baffled and baffled rectangular plates is also deduced.This Works is supported by the National Natural Science Foundation of China (Grant No. 50075029)     

Probability density evolution method for dynamic response analysis of structures with uncertain parameters

Probability density evolution method is proposed for dynamic response analysis of structures with random parameters. In the present paper, a probability density evolution equation (PDEE) is derived according to the principle of preservation of probability. With the state equation expression, the PDEE is further reduced to a one-dimensional partial differential equation. The numerical algorithm is studied through combining the precise time integration method and the finite difference method with TVD schemes. The proposed method can provide the probability density function (PDF) and its evolution, rather than the second-order statistical quantities, of the stochastic responses. Numerical examples, including a SDOF system and an 8-story frame, are investigated. The results demonstrate that the proposed method is of high accuracy and efficiency. Some characteristics of the PDF and its evolution of the stochastic responses are observed. The PDFs evidence heavy variance against time. Usually, they are much irregular and far from well-known regular distribution types. Additionally, the coefficients of variation of the random parameters have significant influence on PDF and second-order statistical quantities of responses of the stochastic structure.The support of the Natural Science Funds for Distinguished Young Scholars of China (Grant No.59825105) and the Natural Science Funds for Innovative Research Groups of China (Grant No.50321803) are gratefully appreciated.     

On the two-dimensional regularized long-wave equation in fluids and plasmas

Summary.  To the two-dimensional regularized long-wave equation we perform computerized symbolic computation to obtain a new auto-B?cklund transformation and picture out some new bell-shaped and anti-bell-shaped solitary waves, which could help in the investigations on the Rossby waves in rotating fluids and the drift waves in plasmas. Received January 8, 2002; revised April 18, 2002 Published online: February 10, 2003 Acknowledgements We thank the editor Prof. N. Aksel and the referees for their valuable comments. This work has been supported by the Excellent Young Teachers Program of the Ministry of Education of China, by the National Key Basic Research Special Foundation (NKBRSF) of China under Grant No.␣G1999032701, by the China Talent Fund, by the National Natural Science Foundation of China under Grant No. 10272017, by the W. T. Wu Foundation on Mathematics Mechanization, by the Talent Construction Special Fund and Basic-Sciences Doctoral Education Fund of Beijing University of Aeronautics and Astronautics. BT also thanks the Enterprise Chair Professors Programme of the Bright Oceans Inter-Telecom Corporation and Beijing University of Posts and Telecommunications. YTG would like to acknowledge the Cheung Kong Scholars Programme of the Ministry of Education of China and Li Ka Shing Foundation of Hong Kong.     

基于ISO质量体系认证在线计量数据智能统计和查询

ISO质量体系认证标准要求对计量数据进行计算和评价。公司的信息管理系统可以自动计算统计参数，并可以方便的进行分析和查询，提高企业工作效率，改善产品质量。论文为国家自然科学基金“现代制造质量控制、溯源中若干理论问题与技术基础的研究”(项目号：59735120)中的一部分。     

Force transmission in three-dimensional hexagonal-close-packed granular arrays with point defect submitted to a point load

We employ the aluminum-plastic board and carbon paper technique to research the contact forces at the bottom boundary of three-dimensional ordered granular arrays with point defects in response to a point load. Our results illuminate that the point defect in the main force chains affects the distribution and transmission of the force greatly while the point defect in the non-main force chains has little effect on the transmission of the force. We further explain these experimental results with a force transmission model. In addition, we find that the point defect in a main force chain not only breaks off this main force chain but also alters the magnitude and direction of other main force chains. We thanks for the support by the National Natural Science Foundation of China (Grant No. 10402012).     

Specification technique for the description of self-optimizing mechatronic systems

The conceivable development of information and communication technology will enable mechatronic systems with inherent partial intelligence. We refer to this by using the term “self-optimization”. Self-optimizing systems react autonomously and flexibly on changing environmental conditions. They are able to learn and optimize their behavior during operation. To develop self-optimizing systems, is a challenge. The principle solution represents a significant milestone because it is the result of the conceptual design as well as the basis for the concretization of the system itself which involves experts from several domains, such as mechanics, electrical engineering/electronics, control engineering and software engineering. This contribution presents a new specification technique for the conceptual design of mechatronic and self-optimizing systems. It also uses the railway technology as a complex example, to demonstrate how to use this specification technique and in which way it profits for the development of future mechanical engineering systems.     

Uncapacitated production planning with multiple product types, returned product remanufacturing, and demand substitution

This paper investigates an uncapacitated multi-product production planning problem with returned product remanufacturing and demand substitution, where no backlog and no disposal are allowed. Both the production of new products and the remanufacturing of returned products are considered to meet time-varying demands in a finite time horizon. Setup costs are taken into account when a new product is manufactured or a returned product is remanufactured. The problem is to determine when and how many returned products are remanufactured and new products are manufactured so as to minimize the total cost, including manufacturing, remanufacturing, holding and substitution costs. We first develop an optimization model to formulate the problem. We then propose a dynamic programming approach to derive the optimal solution in the case with large quantities of returned products. We further propose an approximate approach for the general problem to compute a near-optimal solution. The proposed approaches are evaluated by computational experiments and the effectiveness of the approximate approach is verified. Some managerial insights regarding the effects of remanufacturing/substitution are also obtained from the computational studies. This work was partly supported by the National Science Foundation of China under Grant No. 70329001, 70321001, China Postdoctoral Science Foundation under Grant No. 2003034020, 70501014, SRF for ROCS, SEM (2004) and Hong Kong Research Grants Council under Earmarked Grant No. CUHK 4170/03E. We wish to express our sincere appreciation to the Special Issue Editor and the two referees for their constructive comments and suggestions to help improve our paper.     

Thermal residual stresses in particulate composites and its toughening effect

In this paper, an accurate formula for calculating the thermal residual stress field in a particle-reinforced composite are presented. Numerical examples are given to show r-variations of the thermal residual stresses. The increase in fracture toughness of matrix predicted by the thermal residual stress field is compared well with the experimentally measured increase. This work was supported by the National Natural Science Foundation of China (No.50172053).     

A new algorithm for numerical solution of 3D elastoplastic contact problems with orthotropic friction law

3D elastoplastic frictional contact problems with orthotropic friction law belong to the unspecified boundary problems with nonlinearities in both material and geometric forms. One of the difficulties in solving the problem lies in the determination of the tangential slip states at the contact points. A great amount of computational efforts is needed so as to obtain high accuracy numerical results. Based on a combination of the well known mathematical programming method and iterative method, a finite element model is put forward in this paper. The problems are finally reduced to linear complementarity problems. A specially designed smoothing algorithm based on NCP-function is then applied for solving the problems. Numerical results are given to demonstrate the validity of the model and the algorithm proposed.The project is jointly supported by the National Natural Science Foundation (10225212, 50178016, 10302007), the National Key Basic Research Special Foundation (G1999032805), the Special Funds for Major State Basic Research Projects and the Foundation for University Key Teacher by the Ministry of Education of China. The authors are also grateful to the referees for their careful reading and detailed remarks on an earlier version of the paper.     

Multi-criteria fuzzy decision support for conceptual evaluation in design of mechatronic systems: a quadrotor design case study

Designing mechatronic systems is known to be a very complex and tedious process due to the high number of system components, their multi-physical aspects, the couplings between the different domains involved in the product, and the interacting design objectives. This inherent complexity calls for the crucial need of a systematic and multi-objective design thinking methodology to replace the often-used sequential design approach that tends to deal with the different domains and their corresponding design objectives separately leading to functional but not necessarily optimal designs. Thus, a new approach based on a multi-criteria profile for mechatronic systems is presented in this paper for the conceptual design stage. Additionally, to facilitate fitting the intuitive requirements for decision-making in the presence of interacting criteria, three different methods are proposed and compared using a case study of designing a vision-guided quadrotor drone system. These methods benefit from three different aggregation techniques such as Choquet integral, Sugeno integral and fuzzy-based neural network. To validate the decision yielded by the results of global concept score for each aggregation methods, a computer simulation of a visual servoing system on all design alternatives for quadrotor drone has been performed. It is shown that although the Sugeno fuzzy can be a useful aggregation function for decisions under uncertainty, but the approaches using Choquet fuzzy and fuzzy integral-based neural network seem to be more precise and reliable in a multi-criteria design problem where interaction between the objectives cannot be overlooked.     

Nonlinear Effects in the Josephson Plasma Resonance

Experimental and theoretical studies are reported of the stability of the zero-voltage state of Josephson tunnel junctions in the simultaneous presence of dc bias current and rf field at a frequency comparable to the Josephson plasma frequency. The observations can be qualitatively understood in terms of large amplitude parametric excitation of the plasma mode at fractional harmonics of the plasma frequency. The quasiparticle-pair interference or cos φ current appears to play a significant role in the observed phenomena. Comments are made on nonlinear phenomena in the longitudinal nuclear magnetic resonance in superfiuid ³ He A on the basis of a previously proposed analogy between the two systems. *The experimental work reported here was supported at the University of Pennsylvania by the Army Research Office (Durham) and the Advanced Research Projects Agency. Subsequent analysis by AJD was supported by the U. S. Atomic Energy Commission under Grant No. AT(11-1)-2027 and the National Science Foundation under Grant No. GH-40960, and by DNL by the Army Research Office (Durham) and the National Science Foundation. © 1975 Plenum Publishing Corporation, 227 West 17th Street, New York, N.Y. 10011. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, microfilming, recording, or otherwise, without written permission of the publisher.     

Development of the Chinese Scientometric Indicators (CSI)

We describe the Chinese Scientometric Indicators (CSI), an indicator database derived from the Chinese Science Citation Database (CSCD). Its design is supported by the Natural Sciences Foundation of China (NSFC). In this indicator database data of a statistical nature are organized and categorized leading to ranked lists and providing bases for comparisons among Chinese institutions and regions.     

Finite element formulation of a heat transfer problem for an axisymmetric composite structure

By using weighted residual method, the finite element formulation of a heat transfer problem for axisymmetric composite structures is established from the heat transfer differential equations expressed by heat fluid density. A few examples are included to indicate that the heat transfer anisotropy has an important effect on temperature field and to prove the accuracy and effectiveness of the finite element formulation.Aknowledgement Special thanks are due to the National Natural Science Foundation of China (No: 10272037) for supporting the present work.     

A hard-sphere model of the helium film

A quantum hard-sphere system bounded by two parallel rigid walls is studied at absolute zero as a model of a helium film. A variational wave function is constructed which is of the Bijl-Dingle-Jastrow type modified by a one-body term which vanishes at the walls; Monte Carlo quadrature is used. We focus our attention particularly on the behavior of the single-particle density function and the condensed-state wave function, i.e., the order parameter. Both show significantly different behavior from that predicted by the Hartree theory. The healing length is calculated, we believe for the first time, and is rather small. The average condensate as a function of distance between two walls is also investigated. The calculation serves as a special probe for approximations to the ground-state wave function in a uniform system.This work has been supported by the U.S. Atomic Energy Commission under contract # AT(11-1)-3077 and Grant No. GH-36457 with National Science Foundation.     

Numerical approaches for collaborative data processing

We present an approach to uncertainty propagation in dynamic systems, exploiting information provided by related experimental results along with their models. The approach relies on a solution mapping technique to approximate mathematical models by polynomial surrogate models. We use these surrogate models to formulate prediction bounds in terms of polynomial optimizations. Recent results on polynomial optimizations are then applied to solve the prediction problem. Two examples which illustrate the key aspects of the proposed algorithm are given. The proposed algorithm offers a framework for collaborative data processing among researchers. This work was supported by the National Science Foundation, Information Technology Research Program, Grant No. CTS-0113985.     

Integrated optimization of structure and control for piezoelectric intelligent trusses with uncertain placement of actuators and sensors

The finite element modeling of truss structures with piezoelectric members is presented. Based on the approach of independent modal space control, the controllability and observability indices of the system related to the positions of actuators/sensors are demonstrated. Consequently, the effective damping response time is evaluated. The object of the optimization model is to minimize a specified performance index of the intelligent truss subjected to constraints on the natural frequency and the amplitude of displacement response as well as the applied voltages under a given disturbance. Structural sizing variables, control parameters and actuator/sensor placements are treated as the independent design variables. Coding, the calculation of fitness and the optimization procedure of Genetic Algorithms are discussed so as to solve the integrated optimization with two different types of design variable space: discrete and continuous. Numerical examples are presented to show the effectiveness and usefulness of integrated optimization of structure and control for piezoelectric intelligent trusses.The authors would like to thank for the support by Natural Science Foundation of China under grant 10072050 and the Doctorate Creation Foundation of Northwestern Polytechnical University under grant 200236.     

Computer tools for integrated conceptual design

This paper outlines the conceptual design process with reference to the integrated computer-aided design tool known as Schemebuilder, and the related work of the Lancaster University Engineering Design Centre. The aim of the Lancaster EDC is to provide highly integrated support for the rapid creation and evaluation of a wide range of outline design schemes. Particular attention is paid to the design of mechatronic systems and devices.     

The mechanical properties of (SN)X single crystals

The compression stress-strain behaviour of single crystals of sulphur nitride, (SN)_x, a metallic polymer, was measured in the ambient environment. Measurements were made both parallel and perpendicular to the chain axis on crystals which were about 1 mm in size. The plastic stress-strain behaviour resembled that of a highly anisotropic metal. Deformation to large strains produced a fibrilated structure which graphically exhibits the polymeric nature of (SN)_x. Young's moduli parallel and perpendicular to the chain were 21 and 1.4 GPa respectively. An analysis of the possible slip systems in (SN)_x indicated that there is only one easy glide system, (1 0 0) [0 0 1].Supported by the National Science Foundation MRL Program under Grant No. DMR 76-80994.