CAN通信中位定时的容差分析研究

CAN总线以其高性能、高可靠性及实时性等特点得到广泛应用.然而,这些优越性能在一定程度上受到硬件电路设计的制约.通过研究CAN总线上数据传输的过程,剖析了位定时对硬件偏差的容差能力.研究结论对CAN总线通信系统的设计有一定的指导意义.     

基于ASIC的重置逐比特移位相减开平方计算

采用专用集成电路实现一种功能，一般要考虑以下3个方面：精度、速度和面积。考虑实际芯片的这3个因素，文中采用重置逐比特移位相减法设计了一个开平方的数字专用集成电路。该电路能够对一个32比特的数据进行开平方，最终得到一个16比特的平方根值。该设计面积很小，适用于低频ASIC。     

On Object Representation by Bit Strings for the VKF-Method

An algorithm for the bit-string encoding of objects described by discrete attributes with a binary similarity operation on each attribute value is proposed and analyzed. In this encoding, the bitwise multiplication operation must correspond to the componentwise similarity operation.     

基于样本分布相似度的期望分布鉴别分析

主分量分析(PCA)和线性鉴别分析(LDA)是模式识别领域使用广泛的两种特征抽取方法.本文针对两种方法的不足之处,并从样本分布相似度出发提出一种期望分布鉴别分析(EDDA)方法,抽取到的鉴别特征的总体分布和设定的期望分布最为相近.即通过EDDA得到的投影向量可以抽取出最接近理想分布的鉴别特征.EDDA在投影向量的求解问题上不存在小样本问题,抽取的鉴别特征维数小,并且整体识别性能得到增强.在ORL、Yale人脸库上的实验结果证明本文方法在人脸识别精度上优于PCA和LDA方法.     

实时CORA系统调度模型的分析和比较

分析了TAO系统和NraD/URI系统的调度模型以及分别由Bettati&Sun和东南大学提出的端到端调度模型的模型描述和调度方式.在调度模型的描述能力、计算能力、适用范围和存在的联系等方面对上述调度模型进行了分析和比较.     

透明位图显示方法剖析及改进

提出了显示透明位图的几种方法：建立色彩模型、利用黑白 屏蔽位图、使用Imagelist控件来透明显示图。给出了完备的算法、有效性证明和具体实现 。并且对各方法的优缺点作了比较深入的分析。     

实时CORBA系统调度模型的分析和比较

分析了TAO系统和NraD／URI系统的调度模型以及分别由Bettati＆Sun和东南大学提出的端到端调度模型的模型描述和调度方式。在调度模型的描述能力、计算能力、适用范围和存在的联系等方面对上述调度模型进行了分析和比较。     

Optimal Selection of Uncertain Actions by Maximizing Expected Utility

A new means of action selection via utility fusion is introduced as an alternative to both sensor fusion and command fusion. Distributed asynchronous behaviors indicate the utility of various possible states and their associated uncertainty. A centralized arbiter then combines these utilities and probabilities to determine the optimal action based on the maximization of expected utility. The construction of a utility map allows the system being controlled to be modeled and compensated for; experimental results verify that this approach improves performance.     

素数确定性算法分析

在计算机技术以及密码学高速发展的阶段,提升生成大素数的效率,构建素数库已成为行业趋向.为了探索素数确定性算法的效率和稳定性,提出用算法执行时间和时间曲线斜率的分析方法.通过改进素数确定性算法,计算10个n(n≥106)以内所有的素数,各类算法所需的执行时间,得出算法执行时间曲线来判断算法的效率和稳定性.在结果中,算法执行时间越短算法的效率越高,时间曲线切点斜率越小算法的稳定性越高,得出筛法的执行效率和稳定性远高于试除法、6k±1法优于奇偶过滤法.     

Analysis of Heuristics for Number Partitioning

We illustrate the use of phase transition behavior in the study of heuristics. Using an "annealed" theory, we define a parameter that measures the "constrainedness" of an ensemble of number partitioning problems. We identify a phase transition at a critical value of constrainedness. We then show that constrainedness can be used to analyze and compare algorithms and heuristics for number partitioning in a precise and quantitative manner. For example, we demonstrate that on uniform random problems both the Karmarkar–Karp and greedy heuristics minimize the constrainedness, but that the decisions made by the Karmarkar–Karp heuristic are superior at reducing constrainedness. This supports the better performance observed experimentally for the Karmarkar–Karp heuristic. Our results refute a conjecture of Fu that phase transition behavior does not occur in number partitioning. Additionally, they demonstrate that phase transition behavior is useful for more than just simple benchmarking. It can, for instance, be used to analyze heuristics, and to compare the quality of heuristic solutions.     

基于集对分析联系数的可靠性系统分析与应用

以系统的可靠为参考,则系统的可靠(完全正常地运行)、可靠与不可靠的模糊中介过渡(局部的暂时的轻微的故障,可简称为异常)、不可靠(失效,或简称为反常)就是集对分析意义下的一种同异反,其同(可靠)、异(异常)、反(失效)程度可用集对分析联系数系统地描述,实际问题的可靠性分析就转化为有关联系数的运算与分析,由此形成基于集对分析联系数的可靠性系统分析方法。应用表明,这是一种系统信息丰富、分析性能良好、实用价值明显、具有综合创新意义的可靠性系统分析方法。     

随机数生成器中的信息熵分析

每个在加密系统中的组件都会为它的安全性受到指责,一个明显的错误可能导致一个系统其他方面的崩溃.密码学的随机生成数据经常被使用在如密钥、商业和初始化向量中.使用一个好的RNG对每一个组件来说都是必须的.本文从FreeBSD/Alpha内核的漏洞开始,并重点阐述设计、分析RNG的一些具体实现技术.     

A Note on the Expected Time for Finding Maxima by List Algorithms

Maxima in R ^d are found incrementally by maintaining a linked list and comparing new elements against the linked list. If the elements are independent and uniformly distributed in the unit square [0,1] ^d , then, regardless of how the list is manipulated by an adversary, the expected time is O(n log ^d-2 n) . This should be contrasted with the fact that the expected number of maxima grows as log ^d-1 n , so no adversary can force an expected complexity of n log ^d-1 n . Note that the expected complexity is O(n) for d=2 . Conversely, there are list-manipulating adversaries for which the given bound is attained. However, if we naively add maxima to the list without changing the order, then the expected number of element comparisons is n +o(n) for any . In the paper we also derive new tail bounds and moment inequalities for the number of maxima. Received January 7, 1997; revised June 20, 1997.     

C语言中浮点数的表示范围浅析

浮点数是C语言中的一种数据类型,但在标准C中并没有给出其具体的描述,即数的存储格式及表示范围。部分经典的C语言程序设计教程中给出了浮点数的表示范围,但存在不严谨和值得商榷的地方。结合IEEE754标准,就C语言中浮点数内在存储格式进行分析并给出结论。     

The hardness of the Expected Decision Depth problem

Given a function f over n binary variables, and an ordering of the n variables, we consider the Expected Decision Depth problem. Namely, what is the expected number of bits that need to be observed until the value of the function is determined, when bits of the input are observed according to the given order. Our main finding is that this problem is (essentially) #P-complete. Moreover, the hardness holds even when the function f is represented as a decision tree.     

微波谐振腔模式数的程序求解法

微波谐振腔在无线通信领域应用广泛。在简要微波谐振腔的基础上,给出了用程序求解谐振模式数的方法,并利用C++实现了对给定尺寸矩形谐振腔模式数的求解。     

CAN位时间设计的分析

在简要介绍了已有CAN位时间设计方法后,提出了现有标准的振荡器容差计算值偏松的问题,添加了算式。提出了放宽容差的设计方法。为了减少毛刺的负面影响,选择位时间参数时应作全面的平衡的考虑。     

Linux随机数生成器的分析与应用

介绍了Linux随机数生成器的结构、内部机理,分析了Linux基于系统随机事件熵汇集的随机数提取和更新算法.基于算法分析了OpenWRT的安全性,结果表明OpenWRT存在安全隐患,并提出了改进途径.     

Some Contexts Common for the Number Theory and Harmonic Analysis

Some contexts common for harmonic analysis and number theory are considered. Elements of harmonic analysis are presented in contexts of Rieman integrals, improper integrals, prime finite fields and finite Abelian groups. Contexts of symmetric properties of functions and theory of measure are considered in brief. Applications of the methods and results from the above contexts to some problems of number theory are given.