弱可逆有限自动机的分解

有限自动机公开钥密码体制的提出进一步激励了有限自动机可逆性的研究．在有限自动机公开钥密码体制中首次提出了自动机化合的概念．易知，两个弱可逆有限自动机的化合仍然是一个弱可逆有限自动机并且它的延迟步数不大于前两个有限自动机延迟步数之和．然而，另一方面，如何将一个弱可逆有限自动机分解为两个弱可逆有限自动机的化合却是一个非常困难的问题．该文主要考虑了一类n元严格延迟τ步弱可逆有限自动机M的延迟步数的分解问题．给出了一类特殊的n元弱可逆有限自动机分解的条件和结果．首先证明了如果对M中的每个状态s有T（s，τ）枝等，则M可分解为τ个延迟1步弱可逆有限自动机的化合．然后证明了M可分解为一个τ—m步弱可逆有限自动机和m阶延迟元的充要条件是对M中的每个状态s有T（s，m）枝等．     

二元弱可逆有限自动机延迟步数的分解

本文考虑二元严格延迟τ步弱可逆有限自动机Ｍ的延迟步数的分解问题。首先证明如果Ｍ强连通且所有状态的延迟步数不小于τ－１，则Ｍ一定能分解为一个延迟０步弱可逆有限自动机和一个τ阶延迟元。然后证明如果Ｍ所有状态延迟步数均不小于ｍ，那么Ｍ可以分解为一个严格延τ－ｍ步弱可逆有限自动机和一个ｍ阶延迟元。最后考虑了Ｍ可分解为一个严格延迟τ－１步和一个严格延迟１步弱可逆有限自动机的条件。     

弱可逆拟(r,r)阶存贮线性有限自动机的分解

通过对延迟r步弱可逆拟(r,r)阶存贮线性有限自动机输出权的研究,得出对延迟r步弱可逆拟(r,r)阶存贮线性有限自动机的任意一个状态,它的长r的输出权都是1;任何一个n元拟(r,r)阶存贮线性有限自动机M延迟r步弱可逆的充分必要条件是M都可以分解为一个延迟0步弱可逆有限自动机M0和一个延迟r步弱可逆拟(0,r)阶存贮线性有限自动机M1。     

弱可逆线性有限自动机的一种分解

讨论有限自动机的分解有助于分析弱可逆有限自动机的结构和求解弱逆.首先证明了弱同构的弱可逆有限自动机具有相似的分解形式;接着考虑了一类特殊的弱可逆线性有限自动机的分解,从状态输出权的角度刻画了该分解存在的一个充分条件;然后把这种分解形式推广到了一般的弱可逆线性有限自动机上,即:延迟τ步弱可逆线性有限自动机分解成延迟0步弱可逆有限自动机和一种特殊的有限自动机MD,并得到了分解存在的充要条件;最后,用输出序列的代数性质来刻画其中的充分条件,并把它转化成了一个矩阵的秩的计算.这种分解形式并不局限于n元弱可逆有限自动机,而且分解条件也比较简单,仅与输出序列的性质有关.     

一种有限自动机公开钥密码体制和数字签名

本文提出一种基于有限自动机可逆性理论的公开钥密码体制,它的公开的加密算法由一个非线性延迟O步弱可逆γ阶输入存储有限自动机M和一个延迟τ步可逆(τ,τ)阶存储线性有限自动机M_1经过复合后所得的(τ γ,τ)阶存储有限自动机M所实现,它的秘密的解密算法由M_1的延迟τ步逆M_1′和M的延迟O步弱逆M所实现,这种有限自动机公开钥密码体制的保密性建立在求非线性有限自动机的弱逆的困难性和矩阵多项式因式分解的困难性之上,文中又讨论了用这种密码体制建立数字签名的方法。     

关于弱可逆有限自动机延迟步数分解的两个结果

本文证明存在(任意元)延迟2步弱可逆有限自动机不等价于任何两个延迟1步弱可逆有限自动机的化合的任何子自动机。因而说明了不是对所有的弱可逆有限自动机,延迟步数都是可分解的,但对所有状态的延迟步数均为2的二元延迟2步弱可逆有限自动机,则分解是可行的。     

关于弱可逆线性有限自动机的弱逆的结构

本文研究的主要问题是:对给定延迟τ步弱可逆线性有限自动机M,求出M的所有延迟τ步弱逆线性有限自动机。解决的办法是:首先求出所有M的延迟τ步弱逆的传输函数矩阵,然后对每个传输函数矩降,求出以它为传输函数矩阵的所有M的延迟τ步弱逆。     

关于延迟τ步(可)逆有限自动机结构的一些性质

本文讨论延迟τ步可逆有限自动机M的所有延迟τ步逆有限自动机组成的类的结构问题,和以给定有限自动机M′为延迟′步逆的所有有限自动机组成的类的结构问题。对于输入输出字母表大小相同的情形,给出了构造M的通用延迟τ步逆有限自动机和以M′为延迟τ步逆的通用有限自动机的方法,并证明了在等价的意义下前述两类有限自动机都构成一个分配有界格。     

关于二元延迟3步前馈逆有限自动机的结构

前馈逆有限自动机的结构是有限自动机可逆性理论中的基本问题.对延迟步数≥3的前馈逆结构的刻划,则是一个长期的未解决问题.研究了二元延迟3步前馈逆有限自动机的结构.对于自治有限自动机M_a的状态图为圈的二元延迟3步弱可逆半输入存储有限自动机C(M_af ),给出了其长3极小输出权分别为1,2,8三种情形下结构的一种刻画.由于C(M_af )延迟3步弱可逆当且仅当它是延迟3步弱逆,因此,得到了二元延迟3步前馈逆有限自动机结构的一种部分刻画.     

拟(h,k)存贮有限自动机的可逆性

主要研究拟(h,k)阶存贮有限自动机的延迟k步与k+1步弱可逆性,以及它的弱逆,得到了拟(h,k)阶存贮有限自动机的延迟k步与k+1步弱可逆的充分必要条件,并且通过所得结果可以比较简便地构造出延迟k步与k+1步弱可逆拟(h,k)阶存贮有限自动机的延迟k步与k+1步弱逆.     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

Call for Papers The 6^th International Conference on Grid and Cooperative Computing

Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate