应积极推广应用乘法提前进位法

珠算在利用算盘这个工具进行计算中，它的灵活性是其它计算工具不可比的。     

气体检测系统中BP神经网络的设计与实现

在简要概述气体检测系统原理的基础上,分析了BP神经网络模式识别的特性和结构,阐述了一种基于人工神经网络的混合气体检测方法。分析并研究了气体检测系统中BP神经网络结构的设计方法,构建了基于Matlab的BP网络模型,并实现了对CO、H2S和CH4三种混合气体的定性定量检测。     

点阵码的自动识别方法

对点阵码分布形式进行了分析,本文分析了用最小二乘法将理想点阵图形识别为矢量图的误差,科学地确定了阈值,提出了评价识别结果的判别式.为自动实现矢量化,还提出了点阵图形矢量化的新方法--双向滚动最小二乘识别法,导出了递推公式.本文给出的判据科学准确,提出的矢量化方法快捷高效,具有通用性。     

浅析高分辨率阵列感应测井仪器的应用

本文从分析高分辨率阵列感应测井的原理、优越性及原始测井资料的处理方法入手,结合并分析了其在吐哈油田探井中的具体应用效果。     

基于扰动观察法的光伏系统典型MPPT分析

太阳能光伏组件是非稳定电源,为有效利用太阳能,必须对其进行最大功率点跟踪(MPPT)。现分析了光伏发电MPPT原理,提出一种基于扰动观察法的MPPT控制方法,在Matlab中建立扰动观察法仿真模型,仿真结果显示该算法简洁,容易实现,能够准确地跟踪光伏阵列的最大功率点,且动态性能大大改善。有效地解决了常规的定步长扰动观察法的动态性能与稳态跟踪精度不能同时获得的问题。     

阵列式探针环空找水仪测井探讨

本文主要针阵列式环空找水仪在测井中的优缺点进行探讨,在测井时所得的流量、含水率与井口的化验含水、井口量油进行对比、探讨。     

固定式光伏阵列倾角对辐射量影响分析

本文针对光伏阵列不同倾角时所获得的太阳能辐射量和发电情况，通过模型计算倾斜面上的太阳能辐射量，分析和研究倾角对光伏发电系统的影响。     

存储对桌面云的影响分析

桌面云的应用范围越来越广,从运营商到一些安全性较高的企事业单位,有些已经推广到个人用户,可以说应用前景非常明朗。文章针对市场上现有主流存储的特点以及桌面云系统自身的特点,对存储在桌面云系统中的应用进行了分析及阐述。     

关于单片机加密的软硬件方法

针对单片机开发技术产品的技术保密问题，提出了采用软、硬件技术进行加密的一系列方法。     

九相混合式步进电机环行分配器的研究与设计

本文给出了一种用通用可编程逻辑阵列设计九相混合式步进电机环形分配器的设计思想,使环形分配器的设计更加简明,同时降低了功耗,提高了可靠性.     

A new approach in constructing orthogonal and nearly orthogonal arrays

Orthogonal arrays have been constructed by a number of mathematical tools such as orthogonal Latin squares, Hadamard matrices, group theory and finite fields. Wang and Wu (1992) proposed the concept of a nearly orthogonal array and found a number of such arrays with high efficiency. In this paper we propose some criteria for non-orthogonality and two algorithms for the construction of orthogonal and nearly orthogonal arrays evincing higher efficiency than that obtained by Wang and Wu. Received: September 1999     

基于FPGA的中频电源的任意占空比的n分频器设计

在基于FPGA的中频电源的数字逻辑电路的设计中,常会遇到不同频率的信号,而系统自身的震荡源往往不能满足设计者的要求.本文给出了一种能实现任意占空比任意整数的分频方法,并以5000分频为例,介绍了在QUARTUSⅡ9.0软件下,用Verilog HDL硬件描述语言设计FPGA的分频器.程序通过QUARTUSⅡ9.0仿真和测试,实验结果满足设计要求。     

An effective step-down algorithm for the construction and the identification of nonisomorphic orthogonal arrays

In this paper we present an effective algorithm for the construction and the identification of two-level nonisomorphic orthogonal arrays. Using this algorithm, we identify and list a full catalogue of nonisomorphic orthogonal arrays with parameters OA(24,7,2,t), OA(28,6,2,t) and OA(32,6,2,t), t ≥ 2. Some statistical properties of these designs are also considered.     

18-run nonisomorphic three level orthogonal arrays

In this paper we construct all possible orthogonal arrays OA(18,q, 3,2) with 18 runs and 3 ≤ q ≤ 7 columns and present those that are nonisomorphic. A discussion on the novelty and the superiority of many of the designs found in terms of isomorphism and generalized minimum aberration has been made.      

Optimal nested row-column designs for blocks of size 2×2 under dependence

This paper examines nested 2 ×2 row-column designs when within-block observations are assumed to be dependent. The model considered has fixed block effects, which may also include row and/or column effects. Optimal binary and non-binary designs, constructed from semi-balanced arrays, are given under both generalised and ordinary least squares estimation. It is shown that binary designs are optimal when dependence is low. In general, however, the optimal designs are highly specific to the correlation values. Received: October 1999     

Projection properties of certain three level orthogonal arrays

Two orthogonal arrays based on 3 symbols are said to be isomorphic or combinatorially equivalent if one can be obtained from the other by a sequence of row permutations, column permutations and permutations of symbols in each column. Orthogonal arrays are used as screening designs to identify active main effects, after which the properties of the subdesign for estimating these effects and possibly their interactions become important. Such a subdesign is known as a ``projection design'. In this paper we have identified all the inequivalent projection designs of an OA(27,13,3,2), an OA(18,7,3,2) and an OA(36,13,3,2) into k=3,4 and 5 factors. It is shown that the generalized wordlength pattern criterion proposed by Ma and Fang [23] can distinguish between most, but not all, inequivalent classes. We propose an extension of the Es² criterion (which is commonly used for measuring efficiency of 2-level designs) to distinguish further between the non-isomorphic classes and to measure the efficiency of the designs in these classes. Some concepts on generalized resolution are also discussed.     

A new family of bivariate max-infinitely divisible distributions

In this article we discuss the asymptotic behaviour of the componentwise maxima for a specific bivariate triangular array. Its components are given in terms of linear transformations of bivariate generalised symmetrised Dirichlet random vectors introduced in Fang and Fang (Statistical inference in elliptically contoured and related distributions. Allerton Press, New York, 1990). We show that the componentwise maxima of such triangular arrays is attracted by a bivariate max-infinitely divisible distribution function, provided that the associated random radius is in the Weibull max-domain of attraction.     

高精度数字多用表直流电压的校准

在校准高精度数字多用表直流电压时,为有效减小测量不确定度,可采用直流参考电压和直流分压器作测量标准,使测量不确定度最大程度满足被校仪器和所使用测量标准之间的3倍关系。     

Some orthogonal arrays with 32 runs and their projection properties

Screening designs are useful for situations where a large number of factors are examined but only a few, k, of them are expected to be important. Traditionally orthogonal arrays such as Hadamard matrices and Plackett Burman designs have been studied for this purpose. It is therefore of practical interest for a given k to know all the classes of inequivalent projections of the design into the k dimensions that have certain statistical properties. In this paper we present 15 inequivalent Hadamard matrices of order n=32 constructed from circulant cores. We study their projection properties using several well-known statistical criteria and we provide minimum generalized aberration 2 level designs with 32 runs and up to seven factors that are embedded into these Hadamard matrices. A concept of generalized projectivity and design selection of such designs is also discussed.AMS Subject Classification: Primary 62K15, Secondary 05B20     

AD734模拟乘法器的原理与应用

AD734是一款高速精密四象限模拟乘法器,典型静态满量程误差仅为0.1%,它提供对分母的直接精确控制,这是模拟乘法器的一个新特点。本文主要介绍了AD734的内部结构框图,分母控制电路,最后给出了AD734应用于乘法运算中的电路图。