电池组双向无损均衡充放电模块的设计

由于串联电池组充电时的不均衡,导致电池循环寿命缩短,均衡充电成为了串联电池组充电技术中重要的考虑因素。为改善串联电池组充电时的不平衡,应保证电池组中所有电池的电压都处在同一水平状态。本文设计一种用单片机控制的双向无损均衡充、放电模块,并通过实验验证了该模块的效果。     

提高检波器串抗工频干扰的能力

地震勘探中50Hz工频干扰信号是所采集的地震资料中最强的一种有害信号,在后续资料处理中采用陷波方式消除50Hz信号时容易影响到有用信号。在采集过程中,采用平衡对地电容的方法,可以有效地降低50Hz工频干扰,平均噪声水平达20dB,能有效提高资料品质。     

Computing Longest Previous Factor in linear time and applications

We give two optimal linear-time algorithms for computing the Longest Previous Factor (LPF) array corresponding to a string w. For any position i in w, LPF[i] gives the length of the longest factor of w starting at position i that occurs previously in w. Several properties and applications of LPF are investigated. They include computing the Lempel-Ziv factorization of a string and detecting all repetitions (runs) in a string in linear time independently of the integer alphabet size.     

Computing by Floating Strings

We propose a biologically inspired system which computes on double structures of mobile strings by means of rewriting rules that have a biotechnological implementation, by resembling DNA computations. Its computational universality may be straight deduced from a few formal language theoretical results of one of the authors. Such a DNA-like computational device is naturally described by a membrane system which concludes the paper.     

Strings and the sequence abstraction in Pascal

This paper examines the sequence abstraction known in Pascal as the ‘file’, and shows how sequences of characters (‘strings’ in the SNOBOL sense) may be cleanly fitted into Pascal-like languages. The specific problems of providing the suggested facilities as an experimental extension to Pascal are examined.     

改进的字符串查找算法

字符串匹配效率的提高,能够带来入侵检测系统检测效率的提高.BM、WM是目前常用的字符匹配算法,从这些算法中结合数理统计抽样的思想,本文希望通过抽样检测的方式提高匹配的效率.首先,新算法按照模式字符串的长度,从文本中固定地截取字符作为抽样点;其次,判断该抽样点是否在模式中出现,并从中分离出那些出现在模式中的抽样点.最后,在分离出的抽样点周围进行精确的模式匹配,从中找到模式字符串.此外,本文还给出了算法的正确性证明.     

江汉油田不压井作业技术引进探讨

对江汉油田高压注水井关井后压力扩散情况和部分注水井作业时套管溢流情况进行了调查,分析了油田引进不压井作业技术的必要性和可行性,介绍了油田在注水井不压井作业配套管柱、工具及施工工艺方面的研究成果。     

Finding all periods and initial palindromes of a string in parallel

An optimalO(log logn)-time CRCW-PRAM algorithm for computing all period lengths of a string is presented. Previous parallel algorithms compute the period only if it is shorter than half of the length of the string. The algorithm can be used to find all initial palindromes of a string in the same time and processor bounds. Both algorithms are the fastest possible over a general alphabet. We derive a lower bound for finding initial palindromes by modifying a known lower bound for finding the period length of a string [9]. Whenp processors are available the bounds become (n/p+log_1+p/n2p).This work was partially supported by NSF Grant CCR-90-14605. D. Breslauer was partially supported by an IBM Graduate Fellowship while studying at Columbia University and by a European Research Consortium for Informatics and Mathematics postdoctoral fellowship.     

Disjoint pattern matching and implication in strings

We deal with the problem of deciding whether a given set of string patterns implies the presence of a fixed pattern. While checking whether a set of patterns occurs in a string is solvable in polynomial time, this implication problem is well known to be intractable. Here we consider a version of the problem when patterns in the set are required to be disjoint. We show that for such a version of the problem the situation is reversed: checking whether a set of patterns occurs in a string is NP-complete, but the implication problem is solvable in polynomial time.