产品外形协同设计系统的研究与实现*

提出了协同设计工作模式,给出了系统的工作流程,定义了用户的权限分配,研究了基于交互日志的传输方式,讨论了协同设计过程中的实时更新机制.最后采用了基于MVC的体系结构构建了一个原型系统,该系统在实际应用中,验证了该技术思路的正确性.     

多媒体技术在小学数学教学中的作用

科学技术的日新月异发展,推动了素质教育的进程,多媒体技术已经走进了课堂,本文阐述了小学数学教学应用多媒体技术,激发了学生浓厚的学习兴趣,化解了教学重点难点,营造了良好的氛围,优化了课堂教学,提高了课堂教学效率。     

机会! 有木有?

<正>摩托罗拉移动被谷歌收购了,诺基亚和微软联姻了,惠普退出Web OS了,即使PC业务,惠普也有意让出了,乔布斯辞职了,苹果的威胁是不是会有所降低了?资本市场其实已经给出了最好的说明。市场在变化,这个时候对竞争对手而言,无疑是最好的一次追赶的机会。谷歌跑步入场,跑马圈地正当时摩托罗拉终于在挣扎了许久之后还是放弃了移     

基于电磁感应的矿井探测方法研究及仿真

本文首先分析了矿井探测中遇到的信号干扰种类,结合噪声信号的特点,提出了基于电磁感应的矿井探测方法,给出了其原理图和设计原则.然后详细论述了电磁感应探测方法的具体实现,给出了各主要测试参数的计算公式,明确了在探测过程中需要采集的各种信号.为了验证提出的电磁感应探测方法,最后采用了MATLAB建立了仿真测试模型,并给出了仿真测试结果.     

天下视频Flash 制作下载转换通

宽带流行了,播客兴起了,FLV吃香了,菜鸟也坐不住了,迅即抱回了DV,开通了播客。历经N天修炼,Flash视频终于成为菜鸟的拿手好菜之一。播客的兴起,使得Flash视频(FLV)格式大行其道。究其原因,不外乎FLV视频避免了不安装特定视频插件就     

IT融资：冬去春来，谁当领跑

地震震动了人心,奥运鼓舞了人心,金融海啸席卷了人心。 失业了,郁闷;降息了,还银行贷款少了,高兴。人们在悲喜交织中动荡着。     

让经典延续! Win8开始菜单全攻略

没错,开始菜单从Windows95开始被正式应用到现在,她所带来的便捷已经深入人心,突然升级到Win8了,开始菜单取消了,我们似乎一下子变得无所适从,找不到重启、关机的按钮了,找不到控制面板了,找不到打印机了,找不到需要的程序了,才刚熟悉了在开始菜单中快速搜索文件,现在又不知道     

巧用Linux修复分区逻辑错误

由于我换了块板子,原来的老系统可不能用了,连安全模式都进不去了,郁闷,于是,我便翻出了箱底的XP克隆盘,开始安装XP了.     

基于工作流的B/S模式OA系统设计与实现

根据现代化办公的要求,通过对OA系统中工作流的分析,提出了一个基于工作流的OA系统模型,论述了采用B/S结构的优势,在ASP.NET环境下实现了OA系统的开发,介绍了系统中流程的设计及关键部分的实现细节.本系统功能齐全,使用简便,满足了企事业单位日常办公需求,利用工作流技术和Web环境规范了办公流程,降低了办公成本,提高了办公效率.     

无线互联 纺织未来

因特网的发展引起了新的产业革命,变革了经济的运行模式,刺激了广大企业的创新意识,促进了教育的普及和提高,大大改变发展中国家的工业化模式,甚至会改变国家之间的力量对比。不仅如此,互联网还造就了崭新的一代群体。就像60年代电视改变了人们的娱乐方式,造就了“电视一代”;80年代电脑改变了人们的工作方式,促成了“电脑一代”一样,九十年代Internet改变了人们获取信息的方式,诞生了“网络一代”。互联网对人类社会的影响是深刻而长远的,即给人们带来挑战,更给人们带来机遇。     

High-Order Accurate Adaptive Kernel Compression Time-Stepping Schemes for Fractional Differential Equations

We present a goal-oriented a posteriori error estimator for finite element approximations of a class of homogenization problems. As a rule, homogenization problems are defined through the coupling of a macroscopic solution and the solution of auxiliary problems. In this work we assume that the homogenized problem is known and that it depends on a finite number of auxiliary problems. The accuracy in the goal functional depends therefore on the discretization error of the macroscopic and the auxiliary solutions. We show that it is possible to compute the error contributions of all solution components separately and use this information to balance the different discretization errors. Additionally, we steer a local mesh refinement for both the macroscopic problem and the auxiliary problems. The high efficiency of this approach is shown by numerical examples. These include the upscaling of a periodic diffusion tensor, the case of a Stokes flow over a porous bed, and the homogenization of a fuel cell model which includes the flow in a gas channel over a porous substrate coupled with a multispecies nonlinear transport equation.     

HelSweeper: Screw-sweeps of canal surfaces

A tube is a solid bounded by the union of a one-parameter family of circles that may be decomposed into canal-surfaces and planar disks or annuli. A screw-sweep is the region swept by a shape during a screw motion. HelSweeper computes the boundary of a screw-sweep of an arbitrary union of tubes and polyhedra. To do so, it generates a superset of faces, splits them at their intersections, and selects the face portions that form the desired boundary. The novelty of the proposed approach lies in the fact that the faces contributed to this superset by a tube are each a screw-sweeps of a rigid curve (generator), which is the locus of grazing points, and that each grazing point is formulated as the intersection of a circle of the tube with a corresponding screw-plane. Hence, each such face is a one-parameter family of helices, each being the screw-sweep of a grazing point.     

Control of Motion of an Actively Bending Body in Channels with Dry Friction

Mechanics is described and equations are given of the motion of an actively bending homogeneous body of a finite thickness in a channel with dry friction under conditions of a weak bending. Control is suggested of the motion of a body in a sinusoidal channel, which retains a continuous first derivative of the controlling moment and a bounded second derivative. A process is described of the maximization of the speed of motion by control and then by the choice of the best parameters of a channel. Control is also considered of other modes of the motion of a body in the same channel.     

Track-following control of a dual-stage hard disk drive using a neuro-control system

This paper describes the track-following control of a dual-stage hard disk drive system using neural-networks. A neural-network approach to on-line learning control, and a real-time implementation for a dual-stage hard disk drive, are presented. The use of the dual-stage actuator in hard disk drive systems has become a means of achieving increased servo actuator bandwidth. The dual-stage actuator presented here uses a voice-coil motor (VCM) as a coarse actuator, and a piezoelectric actuator (PZT) as a fine actuator. The control system consists of a series combination of both a plant with a feedback loop and a neural-network with a feedforward loop. The neural-network functions as the reference input filter, and it organizes a new reference signal to the closed-loop circuit. Numerical and experimental results for the track-following control system of the dual-stage hard disk drive show the validity of the proposed neuro-control system.     

Developing a vision-based auto-recharging system for mobile robots

This article describes a vision-based auto-recharging system that guides a mobile robot moving toward a docking station. The system contains a docking station and a mobile robot. The docking station contains a docking structure, a control device, a charger, a safety detection device, and a wireless RF interface. The mobile robot contains a power detection module (voltage and current), an auto-switch, a wireless RF interface, a controller, and a camera. The controller of the power detection module is a Holtek chip. The docking structure is designed with one active degree of freedom and two passive degrees of freedom. For image processing, the mobile robot uses a webcam to capture a real-time image. The image signal is transmitted to the controller of the mobile robot via a USB interface. We use an Otsu algorithm to calculate the distance and orientation of the docking station from the mobile robot. In the experiment, the proposed algorithm guided the mobile robot to the docking station.     

Exact combinatorial bounds on the probability of overfitting for empirical risk minimization

Three general methods for obtaining exact bounds on the probability of overfitting are proposed within statistical learning theory: a method of generating and destroying sets, a recurrent method, and a blockwise method. Six particular cases are considered to illustrate the application of these methods. These are the following model sets of predictors: a pair of predictors, a layer of a Boolean cube, an interval of a Boolean cube, a monotonic chain, a unimodal chain, and a unit neighborhood of the best predictor. For the interval and the unimodal chain, the results of numerical experiments are presented that demonstrate the effects of splitting and similarity on the probability of overfitting.     

A proposal of bargaining solution for cooperative contract in a supply chain

As a problem in supply chain management, the decision problem of terms and conditions of a contract between a supplier and a retailer is recognized commonly. The concept of cooperative bargaining between a supplier and a retailer is the key concepts to resolve this problem in the supply chain. Then, the bargaining evaluation function by Nash in the game theory exists as a tool to obtain the solution by cooperation bargaining. The Nash bargaining solution is derived under the premise that a power balance between a supplier and a retailer is equal. However, the situation where the power balance between a supplier and a retailer in actual bargaining is not equal is supposed frequently. For the purpose of reflecting the power balance in obtaining the bargaining solution, the concept of a general bargaining solution was proposed and then the general bargaining evaluation function for obtaining the general bargaining solution was devised. However, in the case of adopting the general bargaining evaluation function as a bargaining tool, some problems are included. In this article, we address the problems in the general bargaining solution. Then, we propose a new concept of bargaining process to obtain a solution under considering the existence of power balance between a supplier and a retailer.     

Motion of a rigid cylinder between parallel plates in stokes flow : Part 1: Motion in a quiescent fluid and sedimentation

A general numerical scheme for solution of two-dimensional Stokes equations in a multiconnected domain of arbitrary shape [1, 2] is applied to the motion of a rigid circular cylinder between plane parallel boundaries. Numerically generated boundary-conforming coordinates are used to transform the flow domain into a domain with rectilinear boundaries. The transformed Stokes equations in vorticity-stream function form are then solved on a uniform grid using an iterative algorithm. In Part I coefficients of the resistance matrix representing the forces and torque on the cylinder due to its translational motion parallel or perpendicular to the boundaries or due to rotation about its axis are calculated. The solutions are obtained for a wide range of particle radii and positions across the channel. It is found that the force on a particle translating parallel to the boundaries without rotation exhibits a minimum at a position between the channel centerline and the wall and a local maximum on the centerline.

The resistance matrix is utilized to calculate translational and angular velocities of a free particle settling under gravity in a vertical channel. It is found that the translational velocity has a maximum at some lateral position and a minimum on the centerline; the particle angular velocity is opposite in sign to that of a particle rolling along the nearer channel wall except when the gap between the particle and the wall is very small. These results are compared with existing analytical solutions for a small cylindrical particle situated on the channel centerline, and with solutions of related 3-D problems for a spherical particle in a circular tube and in a place channel. It is shown that the behavior of cylindrical and spherical particles in a channel in many cases is qualitatively different. This is attributed to different flow patterns in these two cases. The motion of a spherical particle in a circular tube has qualitative and quantitative features similar to those for a cylindrical particle in a plane channel.     

The probabilistic orienteering problem

The probabilistic orienteering problem (POP) is defined on a directed graph where a cost is associated with each arc and a prize is associated with each node. Moreover, each node will be available for visit only with a certain probability. A server starts from a fixed origin, has a given budget to visit a subset of nodes, and ends at a fixed destination. In a first stage, a node subset has to be selected and a corresponding a priori path has to be determined such that the server can visit all nodes in the subset and reach the destination without exceeding the budget. The list of available nodes in the subset is then revealed. In a second stage, the server follows the a priori path by skipping the absent nodes. The POP consists in determining a first-stage solution that maximizes the expected profit of the second-stage path, where the expected profit is the difference between the expected total prize and the expected total cost.We discuss the relevance of the problem and formulate it as a linear integer stochastic problem. We develop a branch-and-cut approach for the POP and several matheuristic methods, corresponding to different strategies to reduce the search space of the exact method. Extensive computational tests on instances with up to 100 nodes show the effectiveness of the exact method and the efficiency of the matheuristics in finding high quality solutions in a few minutes. Moreover, we provide an extended analysis on a subset of instances to show the value of explicitly modeling the stochastic information in the problem formulation.