Rapid design optimization of antennas using space mapping and response surface approximation models

A computationally efficient method for design optimization of antennas is discussed. It combines space mapping, used as the optimization engine, and response surface approximation, used to create the fast surrogate model of the optimized antenna. The surrogate is configured from the response of the coarse‐mesh electromagnetic model of the antenna, and implemented through kriging interpolation. We provide a comprehensive numerical verification of this technique as well as demonstrate its capability to yield a satisfactory design after a few full‐wave simulations of the original structure. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.     

对象映射关系型数据库技术研究

Object Relationship Mapping(简称ORMapping)是将数据库表映射为面向对象系统中的类,表中的每一条记录则对应为该类的一个具体对象的技术。通过这种技术,可以在软件开发的过程中采用面向对象的方式来处理与数据库相关的部分,比如记录的增加、修改、删除等。讨论了实现OKMapping的几个关键性技术要点,数据库表字段映射对象属性,数据库操作映射面向对象操作,数据库主键外键关联映射对象之间的关系,映射对象如何来适应表结构的变化,事务管理。讨论了ORMapping的性能问题。     

Efficient design of SIW filters by using equivalent circuit models and calibrated space‐mapping optimization

This article presents a very efficient technique for the design of filters in substrate‐integrated waveguide (SIW) technology. The proposed design approach is based on the combined use of equivalent circuit models of SIW discontinuities and a “calibrated” space‐mapping optimization technique. The effectiveness of this design technique is demonstrated through some examples. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010.     

Space mapping algorithm with improved convergence properties for microwave design optimization

Space mapping is one of the most efficient techniques for microwave design optimization. Still, it is well known that space mapping algorithms may suffer from convergence issues, which are consequences of certain fundamental features. In many cases, the space mapping algorithm quickly finds an acceptable solution, but then falls into oscillations with respect to the design variables and/or the objective function value; as a consequence, there are no clear criteria for terminating the optimization process. In this article, we investigate some techniques for improving the convergence properties of the space mapping algorithm, which are based on the general convergence results for such algorithms. Our approach is verified using several microwave design optimization problems. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010.     

An efficient object promotion algorithm for persistent object systems

We report on a bulk object‐loading algorithm for persistent object stores called Ghosted Allocation. It allocates large numbers of objects in a persistent store atomically, efficiently, and reliably. Its main strengths are that it minimizes I/O traffic, optimizes the disk access pattern, and does not impose complex requirements on applications. Our experiments demonstrate that the Ghosted Allocation algorithm is efficient and most importantly scalable, sustaining allocation rates of up to 63 000 objects s^‐1. Copyright © 2001 John Wiley & Sons, Ltd.     

Simulation-based fully Bayesian experimental design for mixed effects models

Bayesian inference has commonly been performed on nonlinear mixed effects models. However, there is a lack of research into performing Bayesian optimal design for nonlinear mixed effects models, especially those that require searches to be performed over several design variables. This is likely due to the fact that it is much more computationally intensive to perform optimal experimental design for nonlinear mixed effects models than it is to perform inference in the Bayesian framework. Fully Bayesian experimental designs for nonlinear mixed effects models are presented, which involve the use of simulation-based optimal design methods to search over both continuous and discrete design spaces. The design problem is to determine the optimal number of subjects and samples per subject, as well as the (near) optimal urine sampling times for a population pharmacokinetic study in horses, so that the population pharmacokinetic parameters can be precisely estimated, subject to cost constraints. The optimal sampling strategies, in terms of the number of subjects and the number of samples per subject, were found to be substantially different between the examples considered in this work, which highlights the fact that the designs are rather problem-dependent and can be addressed using the methods presented.     

一种XML Schema和ontology间的语义映射算法

语义映射是信息集成的重要基础．提出了一种XML Schema和ontology间的语义映射算法,该算法引入了模式图模型，通过该模型计算概念闽的词义匹配度和概念上下文匹配度的加权来计算概念间的相似度，以判断概念是否匹配,实验结果表明，该算法是有效的，能够匹配XSD、WSDL文档和ontology的相应概念.     

Feature-based design and material blending for free-form heterogeneous object modeling

In this paper, a new feature-based method is proposed to represent and design heterogeneous objects. Material governing features are defined to control material composition inside the objects. Interrelations between the material governing features and material attributes are established in the design process and retained in the object model. Free-form B-spline functions are used to represent complex shapes of geometry and material features. A new material feature blending method is used to determine continuous material variation. To obtain the best material features, an optimization problem is constructed based on the object's functional requirements. Variant models are easily generated by changing the geometric and material features using the constraints between them. Implementation and examples are also presented in this paper.     

活动轮廓模型目标跟踪算法综述

目标跟踪是当前计算机视觉领域最活跃的研究主题。首先对基本的跟踪类型进行了介绍;然后讨论了基于活动轮廓模型的图像分割,重点分析了参数活动轮廓模型的梯度矢量流模型（Gradient Vector Flow,GVF）,以及几何活动轮廓模型中的模型;并讨论了基于粒子滤波的目标跟踪算法的研究现状,最后展望了这一领域未来研究的热点。     

数据集成中XML Schema到关系模式的转换方法

根据XML Schema中组件的定义及组件之间的嵌套关系,建立一系列从XML Schema转换成关系模式的结构映射规则和语义映射规则。基于这些规则实现一种转换算法,从Schema中提取出关系模式,并且证明映射得到的关系模式满足4NF。结果表明得到的关系模式不仅包含了XML Schema中所有的结构和内容信息,还能保留大部分语义约束信息,减少存储冗余。     

ONet对象数据库对象组件的改进和实现

面向对象数据库系统ONet遵循了对象数据库标准ODMG3.0,实现了其中C 语言绑定的部分.介绍了目前ONet系统客户端基本结构,分析了客户端使用流程中静态绑定对象模式的缺陷,针对性地提出一种基于动态对象组件的设计方法,详细阐述了运用接口编程,以及组件间的回调技术对现有系统架构进行改进和拆分的方案,使ONet系统最终实现了对象模式的动态加载.     

Schema manipulation in self-describing and self-documenting data models

This paper integrates data, schema and meta-schema into a uniform model and provides one data language to manipulate and modify both data and schema. The modifications on the schema are then propagated to the schema's extension via propagation rules. The integration and the schema modification are all developed within the framework of self-describing and self-documenting models of data and they are fundamental in capturing the evolution of the database, which includes not only data changes, but schema changes as well.This work has been partially supported by NASA under contract NAS 5-26810.     

带纹理映射的牙膏体构造法及其OpenGL实现

在探讨三维Morphing(形状过渡)技术的基础上,提出了一种带不失真纹理映射的牙膏体构造法,较详尽地阐述了三角网格剖分算法的思想.牙膏体是一个包含帽体和膏体两部分的复杂曲面体,从顶部圆台过渡到中间圆面、最后过渡到底部一条直线,它们在拓扑结构上是同构的,因此能通过OpenGL的顶点数组编程加以实现.这种组合曲面造型法不仅方便,还提供丰富的参数选择,具有一定的应用意义,也能有效应用于二维半形状、火箭体和鱼类等绘制.     

基于粒子滤波的未知环境下机器人同时定位、地图构建与目标跟踪

为了解决机器人在未知环境下的目标跟踪问题,提出了一种基于粒子滤波的机器人同时定位、地图构建与目标跟踪方法．该方法采用Rao-Blackwellized粒子滤波器对机器人位姿状态、标志柱分布和目标位置同时进行估计．该方法中,粒子群的总体分布情况表征机器人位姿状态,而每个粒子均包含2类EKF滤波器,其中一类用来完成对标志柱分布的估计,另一类用来完成对目标状态的估计,粒子的权值则由粒子状态相对于标志柱和目标状态2类相似度共同产生．通过仿真和实体机器人实验验证了该方法的有效性．     

对象概念模式及其数据库技术研究

在 E- R分析、语义对象模型和关系数据库的基础上 ,主要结合面向对象方法和数据库特种技术以及笔者在数据库编程方面的实践经验 ,提出了数据库对象概念模式 ,讨论了其中的主要概念 ,并在此模式上重新定义或说明了一些重要的数据库操作 ,如对象集合、时态数据库、多维分析等等     

用设计模式和.Net技术实现对象池设计

为有效管理应用程序执行过程中对资源的使用,通过增加对象池,在调用间根据对象状态动态共享实例,降低总体资源占用.该对象池原型根据.Net平台配置访问对象和缓冲对象的特点,结合状态模式,在抽象可池化对象接口的基础上,实现对池化对象的动态分配与集中管理.单元测试表明对象池原型可以根据配置,动态构造、重用、超时回收对象实例.该原型可以为类似模块的设计提供参考.     

Neural inverse space mapping (NISM) optimization for EM‐based microwave design

We present neural inverse space mapping (NISM) optimization for electromagnetics‐based design of microwave structures. The inverse of the mapping from the fine to the coarse model parameter spaces is exploited for the first time in a space mapping algorithm. NISM optimization does not require up‐front EM simulations, multipoint parameter extraction, or frequency mapping. It employs a simple statistical parameter extraction procedure. The inverse of the mapping is approximated by a neural network whose generalization performance is controlled through a network growing strategy. We contrast our new algorithm with neural space mapping (NSM) optimization. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 136–147, 2003.     

MIDS／BUAA的模式管理器与对象管理器的设计

本文首先回顾了ＭＩＤＳ／ＢＵＡＡ总体设计中相关的部分重要内容，ｕｎｉｖＯｂｊｅｃｔ对象定义，持久性规则、库模式和ＭＩＤＳ的功能构成等。然后重点介绍了ＭＩＤＳ／ＢＵＡＡ中两个核心模块；模式管理器ＳＭ和对象管理器ＯＭ的思想，基本任务和实现途径；最后给出了ＭＩＤＳ／ＢＵＡＡ类库的层次结构。     

空间约束混合高斯运动目标检测

目的 针对传统混合高斯模型前景检测运算量过大问题,提出一种基于空间约束的混合高斯前景检测算法。方法 通过快速初始化缩短模型的初始建立过程;采用双重背景模型机制,以自适应背景减法的前景检测结果作为混合高斯前景检测的空间约束条件,降低模型在背景区域的冗余运算;运用多策略自适应模型更新,提高前景检测的准确性。结果 在各种测试场景下,与传统混合高斯法、CodeBook、GMG、偏差均值混合高斯模型(MODGMM)等算法相比,该算法具有更好的准确率以及4倍以上的处理速度。结论 在固定相机场景下的运动目标检测中,算法能有效提高传统混合高斯法的准确性且具有极高的实时性。