基于布尔差分的数字逻辑电路故障诊断

讨论了数字系统的故障分析的内涵,阐述了故障的可测性定理,并以组合逻辑电路为例,介绍如何利用布尔差分法求解其全部测试码,给出了多重故障测试码的公式,说明了布尔差分法数字系统故障诊断的局限性。     

立方补数的两个渐近公式

在通过对任一正整数提出另外一种唯一分解式的基础上,利用初等方法得到了关于立方补数的几个有趣的渐近公式。     

Kernel Estimation of the Spectral Density of Stationary Random Closed Sets

A non‐parametric kernel estimator of the spectral density of stationary random closed sets is studied. Conditions are derived under which this estimator is asymptotically unbiased and mean‐square consistent. For the planar Boolean model with isotropic compact and convex grains, an averaged version of the kernel estimator is compared with the theoretical spectral density.     

中美常用礼貌用语差异的价值观取向

本文通过对中美文化中一些日常礼貌用语差异的现象分析,阐述了中美文化交际中礼貌用语的价 值观取向,在此基础上论述了价值观取向决定不同文化中礼貌用语的差异。     

关于四元数体上重行列式以及Schur公式

本文在[1][2]的基础上，首先讨论四元数体上的Hermite矩阵的行列式的性质。然后讨论重行列式的性质，对于重行列式，完整地给出了相应于域上行列式的基本性质。最后可把复数域上著名的Schur公式推广到四元数体上。     

Optimal superimposed codes and designs for Renyi''s search model

Renyi (Bull. Amer. Math. Soc. 71 (6) (1965) 809) suggested a combinatorial group testing model, in which the size of a testing group was restricted. In this model, Renyi considered the search of one defective element (significant factor) from the finite set of elements (factors). The corresponding optimal search designs were obtained by Katona (J. Combin. Theory 1 (2) (1966) 174). In the present work, we study Renyi's search model of several significant factors. This problem is closely related to the concept of binary superimposed codes, which were introduced by Kautz and Singleton (IEEE Trans. Inform Theory 10 (4) (1964) 363) and were investigated by D'yachkov and Rykov (Problems Control Inform. Theory 12 (4) (1983) 229), Erdos et al. (Israel J. Math. 51 (1–2) (1985) 75), Ruszinko (J. Combin. Theory Ser. A 66 (1994) 302) and Furedi (J. Combin. Theory Ser. A 73 (1996) 172). Our goal is to prove a lower bound on the search length and to construct the optimal superimposed codes and search designs. The preliminary results have been published by D'yachkov and Rykov (Conference on Computer Science & Engineering Technology, Yerevan, Armenia, September 1997, p. 242).     

Evaluating and improving risk formulas for allocating limited budgets to expensive risk-reduction opportunities

Simple risk formulas, such as risk = probability × impact, or risk = exposure × probability × consequence, or risk = threat × vulnerability × consequence, are built into many commercial risk management software products deployed in public and private organizations. These formulas, which we call risk indices, together with risk matrices, “heat maps,” and other displays based on them, are widely used in applications such as enterprise risk management (ERM), terrorism risk analysis, and occupational safety. But, how well do they serve to guide allocation of limited risk management resources? This article evaluates and compares different risk indices under simplifying conditions favorable to their use (statistically independent, uniformly distributed values of their components; and noninteracting risk‐reduction opportunities). Compared to an optimal (nonindex) approach, simple indices produce inferior resource allocations that for a given cost may reduce risk by as little as 60% of what the optimal decisions would provide, at least in our simple simulations. This article suggests a better risk reduction per unit cost index that achieves 98–100% of the maximum possible risk reduction on these problems for all budget levels except the smallest, which allow very few risks to be addressed. Substantial gains in risk reduction achieved for resources spent can be obtained on our test problems by using this improved index instead of simpler ones that focus only on relative sizes of risk (or of components of risk) in informing risk management priorities and allocating limited risk management resources. This work suggests the need for risk management tools to explicitly consider costs in prioritization activities, particularly in situations where budget restrictions make careful allocation of resources essential for achieving close‐to‐maximum risk‐reduction benefits.     

数字多路选择器树形网络设计理论和算法

利用多路选择器网络可以实现任意逻辑函数的原理和布尔代数运算,提出了基于逻辑函数不相交的简化的积之和形式的数字多路选择器树形网络设计的一种代数方法,该方法可以使待设计的数字多路选择器网络化简到最小树形网络。给出的设计实例说明了该方法是有效的,容易实现数字多路选择器网络的自动综合。