Time- and Space-optimal height-balanced 2-3 brother trees

The node-visit optimal (NVO) and the space-cost optimal (SCO) height-balanced (HB) 2-3 brother trees are defined. The characterization of the NVO HB 2-3 brother trees is developed. This characterization leads to a linear-time algorithm for constructing an NVO HB 2-3 brother tree for an ordered set of keys. The minimum space-cost of an N-key NVO HB2-3 brother tree and the space-cost of an N-key SCO HB 2-3 brother tree is analysed. It is shown that the minimum space-cost of an NVO HB 2-3 brother tree is never more than one plus the space-cost of an SCO HB 2-3 brother tree. Further, the minimum node-visit cost of an SCO HB 2-3 brother tree is at most one plus the node-visit cost of an NVO HB 2-3 brother tree. It is also shown that there exists an HB 2-3 brother tree which is both SCO and NVO for just over half the possible values of keys. Finally, an outline for constructing an SCO HB 2-3 brother tree is presented.     

雷达装备维修器材集装技术研究

多约束条件下的雷达装备维修器材装箱问题是一个复杂的组合优化问题,属于NP完全问题,其求解相当困难.为了解决雷达装备维修器材集装效率低的问题,该文在考虑实际应用的约束条件下,分析并建立了雷达装备维修器材优化装箱问题的模型,采用中间包装,空间分割,空间合并,抽屉分装等策略,提出了一种基于启发式算法的雷达装备维修器材装箱问题的解决方案.仿真实例及实际工作验证了算法的有效性和实用性,较好地解决了雷达装备维修器材的优化装载问题.     

A new EP-based α-β-γ-δ filter for target tracking

This study explores a new fourth-order target-tracking α-β-γ-δ filter using an evolutionary programming (EP) for numerical simulation in view that the current third-order α-β-γ filter system tracks only the target's position and velocity but not its acceleration. As demonstrated, the new α-β-γ-δ filter exhibits a significantly improved tracking accuracy over the conventional α-β-γ filter. Not unexpectedly, however, the new α-β-γ-δ filter takes more computation time in the optimization process. To overcome this weakness, an optimal simulation technique via EP is proposed. The developed EP-based α-β-γ-δ filter finds not only the optimal set of filter parameters to minimize position tracking errors but could also reduce the computation time by up to 95% in some time steps. The trajectory simulated by the EP-based α-β-γ-δ filter is compared with those by other filters to illustrate the efficiency of the former filter.     

Approximation of 1/||x−y|| by Exponentials for Wavelet Applications (Short Communication)

We discuss the approximation of by exponentials in order to apply it to the treatmentof 1/||x-y||. In the case of a wavelet basis, one has in addition the vanishing moment property, which allows to add polynomials without increasing the computational effort. This leads to the question whether an approximation of by the sum of a polynomial and an exponential part yields an improvement. We show that indeed the approximation error is remarkably reduced. The improvement depends on the interval on which is approximated.     

Adaptive Geometrically Balanced Clustering of <Emphasis Type="Italic">H</Emphasis>-Matrices

In [8], a class of (data-sparse) hierarchical (-) matrices is introduced that can be used to efficiently assemble and store stiffness matrices arising in boundary element applications. In this paper, we develop and analyse modifications in the construction of an -matrix that will allow an efficient application to problems involving adaptive mesh refinement. In particular, we present a new clustering algorithm such that, when an -matrix has to be updated due to some adaptive grid refinement, the majority of the previously assembled matrix entries can be kept whereas only a few new entries resulting from the refinement have to be computed. We provide an efficient implementation of the necessary updates and prove for the resulting -matrix that the storage requirements as well as the complexity of the matrix-vector multiplication are almost linear, i.e., AMS Subject Classifications: 65F05, 65F30, 65N38, 65N50.     

How Not to Be Seen

The concept of stealth - as it pertains to computers - shares a great deal with its real-world counterpart. In this article, we take a look at stealth from both a historical and a technological perspective. This is a hugely important topic, for if an unwanted computer program can't be seen, it can't be eliminated. In addition, software developers - especially security software developers - must have a solid understanding of what can be trusted in an environment - and what can't. When it comes to deception, stealth is the state of the art     

Morfit Web-3D仿真建模技术及其应用

该文是一个综述性的应用报告,主要介绍了Morfit Web-3D引擎的功能以及使用它进行环境仿真建模时的作用。Morfit Web-3D引擎集成了当前许多先进的算法和技术进步的成果,采用的是基于图象的3D建模方法。它使得利用数码相机拍摄的图片可以方便地结合到虚拟场景之中,克服了虚拟现实建模过程中构造场景细节时的大量细致和耗费人力的工作。与其它虚拟现实技术相比较在建模的速度上有一定优势。该文详细阐述了Morfit场景的主要构成对象、影响场景中物体显示效果的因数、控制动态物体在场景中运动的方法及创建Morfit Web3D场景的主要步骤。最后通过一个具体实例展示了它的实际应用效果及相关程序设计方法和流程。     

面向对象的工程设计专家系统开发工具OOESTOOL

本文介绍了一个用C 语言开发的支持面向对象功能的工程设计专家系统开发工具OOESTOOL。我们以面向对象的软件开发方法分析并设计OOESTOOL的组成和结构,初步建立了面向对象的知识表示机制和面向对象推理系统,并讨论了面向对象的工程数据库的设计与实现。     

Feasibility of a flip-chip approach to integrate an IR filter and an IR detector in a future gas detection cell

In this work we have studied the feasibility of integrating an infrared filter and an infrared detector by means of a flip-chip technique. This filter and detector combination should be the heart of a future gas detection cell based on infrared absorption. In our case the filter is a surface micromachined Fabry-Perot interferometer, and the infrared detector is a bulk micromachined thermopile. The flip-chip technique is an elegant solution to assure the optical micro-alignment of both devices and allows the electrical contact needed to actuate active optical filters.Work originally presented at DTIP 2003. Spanish CICYT projects no TIC-98-0987-C03-03 and DPI-2001-3213-C02-01 have financed this work.     

Intramolecular C-H--O interaction between lactam oxygen and N-alkyl protons.

We report evidence of an unusual C-H--O interaction between an alpha-methylene hydrogen of the alkylamine chain of substituted (N,N-dimethylamino)propyl-azetidinones, substituted (N,N-dimethylamino)propyl-thiazolidinones and substituted (N,N-dimethylamino)propyl-thiazinone and the lactam carbonyl oxygen. NMR analysis results, supported by molecular mechanic predictions, were in agreement with ab initio calculations. The observed interaction shorting the nitrogen-nitrogen distance in the H1-histamine antagonist, 2-(4-methylphenyl)-3-[3-(N,N-dimethylamino)propyl]-1,3-thiazolidin-4-one (1) could explain its fitting with the H1-antihistaminic pharmacophoric model and the high antihistaminic activity.     

DVB-C接收机中的时钟恢复电路设计

论文提出一种DVB-C基带芯片中全数字时钟恢复电路的解决方案。环路为反馈结构,包括插值器、时钟误差检测和环路滤波器三个部分。A/D提供4倍符号率以上的采样率,误差检测采用Gardner算法,并做线性插值。通过调节环路滤波器的增益减小时钟误差抖动,同时提出一种判断环路锁定的检测方法。仿真结果表明,环路能够捕获400ppm的时钟频率误差,支持16-、32-、64-、128-、256-QAM调制方式,提供稳定收敛和优异的性能。     

一种基于二叉树结构表达的二维实体布局算法

利用二叉树表达二维实体布局问题,得到一个完全自动的二维实体布局算法,算法的复杂性为Ｏ（ｎ）,其中ｎ是区域树的结点数,提出了区域树面积因子等新概念,给出一个精美的旋转区域树的方法,证明了若干基本定理。     

甲苯与异戊二烯合成2,6-二甲基萘的热力学计算

2，6-二甲基萘是合成聚2，6-萘二甲酸乙二酯的重要起始原料。本文讨论了以大宗化工原料甲苯与异戊二烯为起始原料合成2，6-二甲基萘的可能性，并对各种可能化学反应的热力学过程进行了分析，通过分析发现以甲苯与异戊二烯为起始原料经过烷基化、环化及异构化反应可以合成2，6-二甲基萘。同时指出了只有控制异戊二烯合适位置上的碳原子参与烷基化反应才能最终得到目标产物。     

可重构振荡器与双频滤波器的协同设计

实现了一种可重构振荡器与双频率滤波器的协同设计模块。振荡器通过开关二极管的通断来实现频率的可重构,工作频率分别为1.1 GHz和2.0 GHz。与双频滤波器协同设计后,振荡器在两个频率上频偏1 MHz的相位噪声分别从-109.1 dBc/Hz和-112.9 dBc/Hz改善为-125.6 dBc/Hz和-127.9 dBc/Hz,二次谐波抑制分别由协同设计之前的-25 dB和-10 dB改善为-44 dB和-55 dB。     

视频会议系统中对象共享的非上锁协议

本文提出了一种在以桌面视频会议系统为代表的硬实时多任务系统中对象共享的非上锁协议,并推导出在此协议下各任务的定时限制可满足性的充分条件,这表明非上锁共享对象协议是可行的。     

MPD软件包中动态多链路捆绑

本文基于MPD软件包,对MP系统中链路和链路束Bundle的概念进行了分析,并对MP连接的建立方法,动态链路捆绑的设计思路和实现过程进行了说明。     

基于组件的反射中间件的重配置机制研究

中间件平台必须适应各种应用和嵌入式系统的日益增长的不同需求,为此,中间件平台需要具有静态配置和运行时的动态配置的能力。给出了一个面向对象的架构,使用反射的组件模型来管理配置和重配置。     

一种计算航空发动机试车性能的算法

某型涡喷发动机试车需要根据试车测试数据利用标准性能曲线板绘制性能曲线,以确定发动机性能是否合格,这种方法往往具有较大的作图和读数误差.为此利用平面图形二维几何变换的模型,通过对标准性能曲线的平移和旋转来搜索满足条件的性能曲线,并自动计算出发动机的性能.采用枚举搜索法具有方法简单、编程容易的优点,但计算量非常大、搜索效率非常低.为此设计了一种枚举-二分混合搜索的算法,采用在Y方向上枚举、X方向直接平移,旋转过程采用二分搜索的方法,极大地提高了搜索效率,实现了性能曲线的计算.     

跳频电台抗干扰能力分析

文中介绍了跳频电台具有的抗干扰特性,并以200跳VHF跳频电台为例,详细分析了对其进行跟踪干扰的可能性,从正反两方面充分论证了跳频电台具有很强的抗干扰能力。     

应用Textio和Matlab进行数字系统仿真

在基于FPGA的复杂数字系统仿真测试中，设计者常常面临各种挑战。以数字图像处理系统的仿真为例，如果采用完备性仿真测试方法，那么测试矢量的数量将是非常巨大的；而如果采用常规方法，则不仅效率不高，甚至可能无法达到仿真测试的目的。针对这个难题，讨论了一种进行仿真测试的新方法，该方法应用TEXTIO和Matlab来辅助仿真测试过程，使问题得到较好地解决。并且以电视图像实时多目标捕获单元的仿真测试为例，对这个新方法给予全面、细致地讨论。