算法逻辑

本文是一篇算法逻辑的综述文章。对什么是算法逻辑作了有益的探讨,并对当今有代表性的算法逻辑,如 Hoare 逻辑、salwicki 逻辑、Dijkstra 逻辑等作了介绍,还提到了算法逻辑对软件工程的作用以及和数据库理论的关系。     

大变量逻辑函数最佳覆盖问题研究

逻辑函数的最佳覆盖，一直是逻辑综合领域的关键环节。尤其是大变量逻辑函数最佳覆盖，对复杂的逻辑综合更为重要，但也更加困难。本文在对逻辑覆盖算法研究的基础上，提出了适合大变量逻辑函数最佳覆盖的Beister改进算法。经过大量算题的测试表明，改进的列覆盖算法在时间复杂度和选择效果方面均优于Beister算法。     

部分二值逻辑中Sheffer函数的构造与判定算法

在深入研究部分二值逻辑中Sheffer函数的基础上,根据部分二值逻辑中准完备集的最小覆盖,提出了一种高效地构造部分二值逻辑中Sheffer函数的算法,此算法能够构造出部分二值逻辑中的全部Sheffer函数,在构造算法的基础上,进一步提出了一种部分二值逻辑中Sheffer函数的判定算法,此算法和传统判定算法相比,避免了繁琐的计算,可以说是一种较简单的判定算法。     

时态描述逻辑ALC-LTL的Tableau判定算法

时态描述逻辑ALC-LTL将描述逻辑ALC的描述能力与线性时态逻辑LTL的刻画能力结合起来,在具有较强描述能力的同时还使得可满足性问题保持在EXPTIME-完全这个级别。针对ALC-LTL缺少有效的判定算法的现状,将LTL的Tableau判定算法与描述逻辑ALC的推理机制有机地结合起来,给出了ALC-LTL的Tableau判定算法并证明了算法的可终止性、可靠性和完备性。该算法具有很好的可扩展性。当ALC-工`I'I、中的描述逻辑从ALC改变为任何一个具有可判定性特征的描述逻辑X时,只需要对算法进行简单修改,就可以得到相应的时态描述逻辑X-LTL的Tableau判定算法。     

令牌总线局域网中逻辑环维护算法的改进

在令牌总线局域网络中,当逻辑环被破坏时,就要运行逻辑环维护算法。逻辑环维护算法的效率是影响网络实时性的重要因素,也是令牌总线局域网络投入实用的主要难点。本文提出一种逻辑环维护算法。该算法采用“后继站地址搭载的技术”,降低了逻辑环维护的复杂性,减少了逻辑环维护所用的时间,使网络的实时性得以保障。     

逻辑结点函数的优化覆盖

本文提出多级组合逻辑结构中逻辑结点函数的优化覆盖算法、证明了该算法在多级逻辑优化过程中的有效性。     

数据的逻辑综合分析及决策算法

文章给出了逻辑综合分析的基本理论和决策算法。并利用逻辑综合中逻辑单元的随机覆盖问题产生的随机数据,对算法加以验证。实验结果表明决策算法的精确度可以达到97.2%。     

对逻辑函数3种求补算法的分析

对逻辑函数求补中几种不同的求补算法进行了系统的描述和分析研究,使其在逻辑综合领域能发挥更好的作用,这些算法均在项目课题中完成了实现。求补算法的优劣将直接影响逻辑综合优化的效率和时空复杂度,对逻辑函数求补算法进行深入的研究将具有重要的现实意义。     

逻辑结点函数的优化覆盖*

本文提出多级组合逻辑结构中逻辑结点函数的优化覆盖算法，证明了该算法在多级逻辑优化过程中的有效性．     

自动复位快速环树数据采集算法

获取时序可编程逻辑器件内部状态转移关系是可编程逻辑器件逆向分析的关键和安全缺陷分析的基础。在分析现有可编程逻辑器件数据采集算法的基础上,基于环树数据采集算法,提出一种自动复位机制,以实现可编程逻辑器件功能全集数据的采集;针对环树数据采集算法驱动路径动态变化的问题,提出一种动态最短路径算法,以减少状态转移次数,提高采集效率。实验结果显示,自动复位快速环树数据采集算法不仅实现了可编程逻辑器件功能全集数据的正确采集,而且数据采集效率比现有算法提高了约9%。     

逻辑函数的双逻辑综合与优化

针对传统布尔逻辑在电路面积优化中存在的不足,提出了一种用传统布尔逻辑和Reed-Muller(RM)逻辑相结合的双逻辑优化算法.通过将原逻辑函数的乘积项转化为不相交乘积项,并利用不相交乘积项的位操作,将逻辑函数的覆盖分成2个部分,使之分别适合布尔逻辑综合和RM逻辑综合;同时提出了适合双逻辑函数的逻辑功能验证方法.双逻辑优化算法用C语言编程实现并用MCNC标准电路进行测试.实验结果表明,与单一的布尔逻辑综合结果相比,在绝大多数情况下文中算法可使电路面积获得进一步优化.     

Dynamically changing the logical behavior of the microcomputerinterface

Industrial programmable controllers and hardware simulators currently use the software method of direct logic simulation. In this method, programs contain the logical functions of several Boolean variables that are encoded directly. Each combinational circuit expressed by a group of Boolean equations requires an independent program. An alternative solution for the software implementation of the Boolean equations, named the product terms method, is presented. This method features the use of a single program to implement any multiple-output combinational circuit. To make the distinction between different circuits, a block of data defines each circuit. The product method is extended to synchronous sequential circuits, for which two tables are used. One table determines the next state of the combinational circuit, and the second table determines the outputs. An expert system has been developed to generate the table used in the product terms by interpreting the symbolic Boolean equations supplied by the user. The implementation and testing of the method are described     

PSO based approach for scheduling NPD projects including overlapping process

The efficient scheduling of the new product development (NPD) projects is important to reduce the required development time, and to offer the new product faster. Activity overlapping is commonly regarded as the most promising strategy to reduce product development times. However, overlapping must be well-planned by weighting the gain from the activity overlapping against the additional time for rework. The objective of this research was to develop a resource constrained scheduling methodology for NPD projects considering overlapping of activity couples. A particle swarm optimization based approach is used to schedule NPD projects that include overlapping process. The proposed PSO method is developed into a user friendly system so that the practitioners can utilize it. A real-life example of a product development project taken from the literature is used to show the efficiency of the software.     

Multiplicative Properties of Spectral Walsh Coefficients of the Boolean Function

It is shown for the first time that spectral Walsh coefficients of the Boolean function have the structure in the form of the product of Walsh derivatives of this function. A method and an algorithm are suggested for the analysis of multiplicative properties of Walsh coefficients in terms of the behavior of the Boolean function and results of the experiments on test logic circuits are given.     

制造服务逻辑关系确定方法研究

Web服务环境下,为了快速建立制造服务链,提出了一种制造服务逻辑关系的确定方法。首先分析了产品结构、制造任务和制造服务三者之间的关系,提出了基于产品结构建立制造服务链的过程,然后论述了制造任务时序关系的确定方法,定义了基于产品结构的制造服务分类模型,最后给出了制造服务逻辑关系的确定规则。     

EDOA: an efficient delay optimization approach for mixed-polarity Reed-Muller logic circuits under the unit delay model

Delay optimization has recently attracted significant attention. However, few studies have focused on the delay optimization of mixed-polarity Reed-Muller (MPRM) logic circuits. In this paper, we propose an efficient delay optimization approach (EDOA) for MPRM logic circuits under the unit delay model, which can derive an optimal MPRM logic circuit with minimum delay. First, the simplest MPRM expression with the fewest number of product terms is obtained using a novel Reed-Muller expression simplification approach (RMESA) considering don’t-care terms. Second, a minimum delay decomposition approach based on a Huffman tree construction algorithm is utilized on the simplestMPRM expression. Experimental results on MCNC benchmark circuits demonstrate that compared to the Berkeley SIS 1.2 and ABC, the EDOA can significantly reduce delay for most circuits. Furthermore, for a few circuits, while reducing delay, the EDOA incurs an area penalty.     

Existential rigidity and many modalities in order-sorted logic

Order-sorted logic is a useful tool for knowledge representation and reasoning because it enables representation of sorted terms and formulas along with partially ordered sorts (called sort-hierarchy). However, this logic cannot represent more complex sorted expressions when they are true in any possible world (as rigid) or some possible worlds (as modality) such as time, space, belief, or situation. In this study, we extend order-sorted logic by introducing existential rigidity and many modalities. In the extended logic, sorted modal formulas are interpreted over the Cartesian product of sets of possible worlds. We present a new labeled tableau calculus to check the (un)satisfiability and validity of sorted modal formulas.     

一个基于模糊神经网络的模式分类系统

目前,基于神经网络的分类系统在许多领域得到了越来越广泛的应用。但是,该系统大多采用的是离线自适应机制,即神经网络需学习新的分类知识时,要重新训练神经网络,从而大大增加神经网络的训练时间;对于重叠分类,一般是构成一个贝叶斯分类器。然而,贝叶斯分类器的构成需要关于分类数据的概率密度函数的先验知识,而这些知识常常在模式分类前是难以获得的。为了解决这些问题,文中根据模糊集合理论,提出了一种基于模糊神经网络     

计算机与FX2N系列PLC串行通信的几种方法

串行通信是计算机监控系统中可编程控制器(PLC)与上位机通信的主要方式。介绍基于内置编程接口、RS-232C和RS-485的计算机与三菱FX2N系列PLC串行通信的方法,包括硬件连接、软件设置和程序编写,从通信有效距离、附加装置、PLC资源点数等方面对这些方法进行比较,提出选择适当的方法时需要考虑的几点问题,并以回转窑...     

A fuzzy-logic-based approach for new product Go/NoGo decision at the front end

New product development (NPD) is both a complex process and a substantial business risk. It still requires 6.6 ideas to generate a successful product. Thus, researchers claim that inferior new products should be eliminated at the front end. Limited by both the nature and the timing of NPD, managers often perform screening in uncertain environments and based on incomplete information. Furthermore, the conventional evaluation approaches, which encapsulate or merely discard the ambiguity and multiplicity of possible concerns, make a screening economically sound but dysfunctional as well. Since most assessments are described subjectively by linguistic terms, a comprehensive method for new product screening using fuzzy logic is proposed, in which the criteria ratings and their corresponding importance are assessed in linguistic terms described by fuzzy numbers, and fuzzy weighted average is employed to aggregate these fuzzy numbers into a fuzzy-possible-success rating (FPSR) of the product. Finally, the FPSR is translated back into linguistic terms to derive at a new product screening decision. Furthermore, a case study is cited to illustrate the performance within an actual decision process. The result shows that this approach can efficiently aid managers dealing with ambiguity and complex environments in achieving relatively realistic and informative results, as well as give managers a high degree of flexibility in decision-making. In addition, the variations in linguistic values and levels of linguistic variables have an effect on the ranges of the FPSR which ultimately, affect the selection of the NPD project.