Dynamics of the 6-6 Stewart parallel manipulator

Recursive matrix relations in kinematics and dynamics of the 6-6 Stewart–Gough parallel manipulator having six mobile prismatic actuators are established in this paper. Controlled by six forces, the manipulator prototype is a spatial six-degrees-of-freedom mechanical system with six parallel legs connecting to the moving platform. Knowing the position and the general motion of the platform, we develop first the inverse kinematics problem and determine the position, velocity and acceleration of each manipulator’s link. Further, the inverse dynamics problem is solved using an approach based on the principle of virtual work, but it has been verified the results in the framework of the Lagrange equations with their multipliers. Finally, compact matrix relations and graphs of simulation for the input velocities and accelerations, the input forces and powers are obtained.     

Data Hiding in Audio Using Random Orthogonal Matrices

ABSTRACT

In this paper, speech scrambling is done to secure the data and at the same time covert information is embedded in scrambled speech that can be transmitted through communication channel. The technique performs encryption by scrambling the spectral components of speech using random orthogonal matrices. At the receiver end, hidden message and original speech are recovered by decoding and decrypting the scrambled signal, respectively. Performance of technique is evaluated in clean and noisy channel environments.     

基于ADAMS的并联机器人运动学和动力学仿真

应用机械系统动力学仿真分析软件ADAMS,建立了Stewart型并联机构的虚拟样机模型,包括对并联机器人各部件的简化方法、在ADAMS中的模型描述及仿真过程控制,并利用该虚拟样机模型对并联机器人进行了运动学和动力学分析。为并联机器人系统的设计、制造和模拟运动作业提供了理论依据和主要参数。实现了在计算机上通过使用CAE仿真软件朱对并联机器人的运动和动力性能进行分析,为并联机器人的设计提供了一套有效的分析方法。     

高阶类型化软件体系结构建模和验证及案例

根据权威统计数据，软件测试中发现的70%以上的错误由需求获取或体系结构设计引起.因此，应用软件体系结构在设计阶段的正确性验证非常重要.现有的软件体系结构设计方法不支持需求满足验证，需求满足验证需要其他验证工具的支持.面向主流Web应用软件的体系结构设计及其需求满足验证，提出了一种高阶类型化软件体系结构建模和验证语言（SAML）与软件体系结构建模和验证方法（SAMM）.SAML语言通过定义类型和项的语法及语义，描述软件体系结构中类型和对象的构造，通过定义类型规则及其类型检查算法来判定Γ|-t：T和Γ|-R（T₁，T₂）是否成立.SAMM给出了软件体系结构建模范式，包括构建接口类型M_cls（type interface）、组件M_cmpt（component）、容器M_cont（container）、框M_frm（frame）和框架M_frwk（framework）这5层建模过程，以及生成层内与层间类型之间关系对应的类型规则，同时定义了接口类型方法调用图（G_SA）用以刻画软件体系结构设计要求，定义了类型序列及其正确性用以刻画需求期望的性质，并给出了相应的验证算法.设计实现了基于该方法的原型工具系统SAMVS，其中，模型编辑环境支持应用软件的设计过程，验证环境支持设计满足需求的自动化验证.通过一个实际案例，完成了一个较大规模"互联网+"应用软件系统的体系结构建模和验证.     

双反对称矩阵反问题解存在的条件

112 数值计算与计算机应用2002年51.问题的提出矩阵反问题及逆特征值问题在工程中应用广泛,关于它们的     

A Concern-based Technique for Architecture Modelling Using the UML Package Merge

In this paper, we present a concern-based technique for software architecture modelling. We use the new UML 2 Package Merge relationship as a technique for the separation of concerns. We present the advantages of using the UML Package Merge relationship for software architecture modelling, and we propose a set of extensions for its limitations.     

Modelling and animating faces using scanned data

This paper extends a physically-based approach to the realistic modelling and animation of human heads using scanned data. A three-step procedure is proposed which begins with geometry and colour data acquired from a subject's head using a radial laser scanner, continues with the construction of a 3D model of the head with complete colour texture mapping, and culminates in real-time, interactive facial animation. First, an adaptive meshing technique is described that creates non-uniform facial meshes from the densely sampled data. These geometrically accurate facial meshes adapt to features of interest in the data, increasing polygon density over articulate face regions and areas of high curvature. Secondly, the mesh is transformed into a physically-based head model of the subject. This incorporates a physical approximation to facial tissue and a set of anatomically-motivated facial muscle actuators. Finally, these components are integrated in a facial modelling and animation system.     

区间矩阵的鲁棒稳定性判据

基于一种非线性的幂变换,将区间矩阵的鲁棒稳定性问题转化成相应参数矩阵的非奇异性问题,并结合Gershgorin圆盘定理,得到了保证系统鲁棒稳定的充分条件。该判据对矩阵元素没有任何附加要求,简单而且实用。最后通过实例论证了所给判据的有效性。     

Dynamic Load Balancing for Short-range Parallel Molecular Dynamics Simulations

The iterative Multilevel Averaging Weight (MAW) algorithm presented in paper [1] is modified to solve the dynamic load imbalance problems arising from the two-dimensional short-range parallel molecular dynamics simulations in this paper. Firstly, five types of load balancing models are given which allows detailed studies of the algorithm. In particular, it shows that for strip decomposition, the number of iteration needs for the system to converge from an initially unbalanced state to a well balanced state is bounded by 2 log P , where P is the number of processors. This result can permit the algorithm to efficiently track fluctuations in the molecular density as the simulation progresses, and is much better than that of the Cellular Automaton Diffusion (CAD) scheme presented in paper [2] . Secondly, we apply MAW algorithm to solve the load imbalance problem in the parallel molecular dynamics simulation for higher speed wall collisions. At last, the numerical experimental results and parallel computing performance with MPI-1.2 under a PC-Cluster consists of 64 Pentium-III 500 MHz nodes connected by 100 Mbps Switches are given in this paper.     

Modelling using an extended Yule distribution

A biparametric discrete distribution that extends the Yule distribution is presented. It belongs to the family of distributions generated by the Gaussian hypergeometric function and it can be expressed as a generalized beta mixture of a geometric distribution. The introduction of a new parameter makes the model very suitable to fit the empiric distribution tails and the effect of infinite variance is not possible. Several examples show more accurate fits when the extended distribution is used and the results are compared with other biparametric extensions of the Yule distribution.     

Modelling the Belgian gas consumption using neural networks

In this paper an accurate neural network model is proposed for the gas consumption in Belgium. It is a static non-linear model, based on monthly data and contains the following inputs: temperature, difference between real and expected temperature, oil price, number of domestic clients and consumption by industry. Various interpretations are made on the identified models such as yearly error, normalized gas consumption, growth rate, uncertain linear model interpretation and sensitivity of the consumption with respect to the temperature. In contrast to traditional models, which depend only on the temperature, the present neural network models show excellent generalization ability, with small yearly errors on training and test set.This research work was carried out at the ESAT laboratory and the Interdisciplinary Center of Neural Networks, ICNN, of the Katholieke Universiteit Leuven in the framework of the Belgian Programme on Inter-university Poles of Attraction, initiated by the Belgian State, Prime Minister's Office for Science, Technology and Culture (IUAP-17), and in the framework of a Concerted Action Project MIPS (Model-based Information Processing Systems) of the Flemish Community, It is sponsored by Electrabel.     

区间矩阵稳定的新充分必要条件

本文讨论了对称区间矩阵的稳定性并给出了一个简单的充分必要条件，同时还讨论了线性时变区间矩阵和非线性时变区间矩阵的稳定性。     

Dynamics of the spherical 3- \mathit{U\underline{P}S/}S parallel mechanism with prismatic actuators

Recursive relations in kinematics and dynamics of the symmetric spherical 3- parallel mechanism having three prismatic actuators are established in this paper. Controlled by three forces, the parallel manipulator is a 3-DOF mechanical system with three parallel legs connecting to the moving platform. Knowing the position and the rotation motion of the platform, we develop first the inverse kinematics problem and determine the position, velocity, and acceleration of each manipulator’s link. Further, the inverse dynamic problem is solved using an approach based on the principle of virtual work, but it has been verified using the results in the framework of the Lagrange equations with their multipliers. Finally, compact matrix relations and graphs of simulation for the input forces and powers are obtained.     

高阶类型化可验证应用系统体系结构建模及案例

随着应用软件体系结构风格变化和规模变大,其运行环境变得日趋复杂,对应用系统体系结构的设计及其正确性验证提出了新的挑战.现有的应用系统体系结构设计关于需求满足性验证在建模与验证中需要多种工具的支持.应用系统体系结构在设计阶段的需求满足验证,有助于客观评价应用系统部署方案和系统如期上线以及主动运维.面向应用系统体系结构设计及其验证,在模型驱动的软件工程背景下提出一种高阶类型化可验证应用系统体系结构建模语言(V_ASAML)与可验证应用系统体系结构建模方法(V_ASAMM).V_ASAML语言通过定义类型和项的语法和语义,描述构成应用系统体系结构的类型和对象的结构,通过定义两种类型规则及其类型检查算法,判定Γt:T和ΓR(T₁,T₂)是否成立,其中,结构类类型规则用于描述应用系统体系结构中的组成部分,关系类类型规则用于描述组成部分之间的关系和配置.V_ASAMM方法给出了应用系统体系结构建模过程,包括构建M_bd(基本数据类型)、M_bti<...     

The parallel computation of eigenvalues and eigenvectors of large Hermitian matrices using the AMT DAP 510

The solution of the algebraic eigenvalue problem is an important component of many applications in science and engineering. With the advent of novel architecture machines, much research effort is now being expended in the search for parallel algorithms for the computation of eigensystems which can gainfully exploit the processing power which these machines provide. Among important recent work References 1-4 address the real symmetric eigenproblem in both its dense and sparse forms, Reference 5 treats the unsymmetric eigenproblem, and Reference 6 investigates the solution of the generalized eigenproblem. In this paper two algorithms for the parallel computation of the eigensolution of Hermitian matrices on an array processor are presented. These algorithms are based on the Parallel Orthogonal Transformation algorithm (POT) for the solution of real symmetric matrices[7,8]. POT was developed to exploit the SIMD parallelism supported by array processors such as the AMT DAP 510. The new algorithms use the highly efficient implementation strategies devised for use in POT. The implementations of the algorithms permit the computation of the eigensolution of matrices whose order exceeds the mesh size of the array processor used. A comparison of the efficiency of the two algorithms for the solution of a variety of matrices is given.     

Kinematics, dynamics and construction of a planarly actuated parallel robot

Kinematic and dynamic analysis of a parallel robot consisting of three planarly actuated links, is presented in this paper. Coordinated motion of three planar motors, connected to three fixed-length links, produces a six-degrees-of-freedom motion of an output link. Its extremely simple design along with much larger work volume than the commonly used parallel robots make this high performance-to-simplicity ratio robot very attractive. Experimental model verifies the unique combination of large work volume and high accuracy of this robot.     

Specification,analysis and simulation of the dynamics within an organisation

In this paper a modelling approach to the dynamics within a multi-agent organisation is presented. A declarative, executable specification language for dynamics within an organisation is proposed as a basis for simulation. Moreover, to be able to specify and analyse dynamic properties within an organisation, another declarative specification language is put forward, which is much more expressive than the executable language for simulations. Supporting tools have been implemented that consist of a software environment for simulation of organisation models and a software environment for analysis of dynamic properties against traces of dynamics within an organisation.     

Modelling sequences using pairwise relational features

We propose a new framework for the modelling of sequences that generalizes popular models such as hidden Markov models. Our approach relies on the use of relational features that describe relationships between observations in a sequence. The use of such relational features allows implementing a variety of models from traditional Markovian models to richer models that exhibit robustness to various kinds of deformation in the input signal. We derive inference and training algorithms for our framework and provide experimental results on on-line handwriting data. We show how the models we propose may be useful for a variety of traditional tasks such as sequence classification but also for applications more related to diagnosis such as partial matching of sequences.     

鲁棒性问题中出现的两个多项式方阵凸组合的稳定性

本文考虑两个多项式方阵凸组合的鲁棒稳定性。给出判别这一稳定性的充分必要条件和一个算法。     

Modelling of Complete Robot Dynamics Based on a Multi-Dimensional, RBF-like Neural Architecture

A neural network based identification approach of manipulator dynamics is presented. For a structured modelling, RBF-like static neural networks are used in order to represent and adapt all model parameters with their non-linear dependences on the joint positions. The neural architecture is hierarchically organised to reach optimal adjustment to structural apriori-knowledge about the identification problem. The model structure is substantially simplified by general system analysis independent of robot type. But also a lot of specific features of the utilised experimental robot are taken into account.A fixed, grid based neuron placement together with application of B-spline polynomial basis functions is utilised favourably for a very effective recursive implementation of the neural architecture. Thus, an online identification of a dynamic model is submitted for a complete 6 joint industrial robot.