国产梁式引线器件平面集成混频器

介绍鳍线单平衡混频器电路的设计。混频器使用国产梁式引线混频二极管。混频器在31～37GHz的频率范围内,变频损耗小于10dB,最小值为7.2dB。     

A spanning heuristic for the unordered and ordered matching identification problem

The matching identification problem (MIP) is a combinatoric search problem related to the fields of learning from examples, boolean functions, and knowledge acquisition. The MIP involves identifying a single “goal” item from a large set of items. Because there is commonly a cost associated with evaluating each guess, the goal item should be identified in as few guesses as possible. As in most search problems, the items have a similar structure, which allows an evaluation of each guessed item. In other words, each guessed item elicits partial information about the goal item, i.e. how similar the guess is to the goal. With this information the goal is more quickly identified.The unordered MIP has been studied by Mehrez and Steinberg (ORSA J. Comput. 7 (1995) 211) in which they proposed two different types of algorithms. The purpose of the present paper is to suggest an improved Spanning Heuristic algorithm. Its improvement increases as the problem size increases. Further results and comparisons are derived for the unordered and ordered cases.This research shows that when the search space is very large, it is better to inquire from items that are known not to be the goal (they have been ruled out by previous guesses), for the purpose of acquiring more information about the goal. As the search space is narrowed, it is better to guess items that have not been ruled out.     

On Approximability of Boolean Formula Minimization

For a Boolean function given by a Boolean formula (or a binary circuit) S we discuss the problem of building a Boolean formula (binary circuit) of minimal size, which computes the function g equivalent to , or -equivalent to , i.e., . In this paper we prove that if P NP then this problem can not be approximated with a good approximation ratio by a polynomial time algorithm.     

Perfect simulation for correlated Poisson random variables conditioned to be positive

In this paper we present a perfect simulation method for obtaining perfect samples from collections of correlated Poisson random variables conditioned to be positive. We show how to use this method to produce a perfect sample from a Boolean model conditioned to cover a set of points: in W.S. Kendall and E. Thönnes (Pattern Recognition 32(9): 1569–1586, 1999), this special case was treated in a more complicated way. The method is applied to several simple examples where exact calculations can be made, so as to check correctness of the program using ²-tests, and some small-scale experiments are carried out to explore the behaviour of the conditioned Boolean model.     

Likelihood Inference for Unions of Interacting Discs

Abstract. This is probably the first paper which discusses likelihood inference for a random set using a germ‐grain model, where the individual grains are unobservable, edge effects occur and other complications appear. We consider the case where the grains form a disc process modelled by a marked point process, where the germs are the centres and the marks are the associated radii of the discs. We propose to use a recent parametric class of interacting disc process models, where the minimal sufficient statistic depends on various geometric properties of the random set, and the density is specified with respect to a given marked Poisson model (i.e. a Boolean model). We show how edge effects and other complications can be handled by considering a certain conditional likelihood. Our methodology is illustrated by analysing Peter Diggle's heather data set, where we discuss the results of simulation‐based maximum likelihood inference and the effect of specifying different reference Poisson models.     

深亚微米MOS器件模型BSIM2及其参数提取

详细分析了适用于ＶＬＳＩ／ＵＬＳＩ设计的深亚微米ＢＳＩＭ２ＭＯＳ器件模型，并在深入讨论短沟道ＭＯＳ器件物理效应的基础上，对沟道长１μｍ栅氧化层厚度２５ｎｍ的ｎＭＯＳＦＥＴ进行了测试和ＢＳＩＭ２模型参数的提取，且对结果进行了分析和讨论。结果表明，ＢＳＩＭ２具有精确、参数易提取、计算速度快的特点，是ＶＬＳＩ／ＵＬＳＩ模拟设计的重要工具之一。     

“电路基础”课程双语教学的研究与实践

在教学实践中开展“电路基础”课程双语教学的方法探索表明，采用多种模式的教学方法、编写电路专业词汇英汉对照表、开展有效的课外教学活动、采取综合考评方法是受学生欢迎的行之有效的教学方法。     

EWB-电子线路设计与教学的优秀工具

介绍EWB(ElectronicsWorkbench即电子工作台 )软件对电子线路设计与教学的意义及其特点、功能和使用方法     

Genetic programming as a means for programming computers by natural selection

Many seemingly different problems in machine learning, artificial intelligence, and symbolic processing can be viewed as requiring the discovery of a computer program that produces some desired output for particular inputs. When viewed in this way, the process of solving these problems becomes equivalent to searching a space of possible computer programs for a highly fit individual computer program. The recently developed genetic programming paradigm described herein provides a way to search the space of possible computer programs for a highly fit individual computer program to solve (or approximately solve) a surprising variety of different problems from different fields. In genetic programming, populations of computer programs are genetically bred using the Darwinian principle of survival of the fittest and using a genetic crossover (sexual recombination) operator appropriate for genetically mating computer programs. Genetic programming is illustrated via an example of machine learning of the Boolean 11-multiplexer function and symbolic regression of the econometric exchange equation from noisy empirical data.Hierarchical automatic function definition enables genetic programming to define potentially useful functions automatically and dynamically during a run, much as a human programmer writing a complex computer program creates subroutines (procedures, functions) to perform groups of steps which must be performed with different instantiations of the dummy variables (formal parameters) in more than one place in the main program. Hierarchical automatic function definition is illustrated via the machine learning of the Boolean 11-parity function.     

量子逻辑述评

量子力学已经在众多的领域中有着十分有效的应用,但对它的解释、它的概念基础及哲学涵义等问题,从它产生之日至今,却一直还是理论物理学家及科学哲学家中争论不休的问题.笔者在对量子逻辑的起源和量子逻辑与经典逻辑的关系进行介绍的基础上,提出对量子逻辑研究方向的展望.