网孔处理机阵列上最小生成树算法

已知一加权无向图G(V,E),|V|=n.本文基于网孔处理机阵列,运用分而治之策略和数据归约技术给出了一种新的最小生成树算法.此算法需O(n~2/p)时间,使用了O(p)个处理机(1≤p≤n).当p=n时,此算法仅需O(n)时间和O(n)处理机.而目前基于同一计算模型上此问题的最好算法需O(n)时间和O(n~2)个处理机,因而这里给出的算法在使用处理机数目方面改进了O(n)因子.     

虫孔路由二维网孔机器上的最优图论算法

连通分量和最小生成树是图论中的两个基本问题 ,在许多领域都有很多应用 .对于顶点数为 n的图和规模为 p× p的虫孔路由二维网孔机器 ,该文针对 p n和 n

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最长公共子序列问题的改进快速算法

现在几个最常用的解决最长公共子序列(LCS)问题的算法的时间复杂度分别是O(pn),O(n(m-p)).这里m、n为两个待比较字符串的长度,p是最长公共子串的长度.给出一种时间复杂度为O(p(m-p)),空间复杂度为O(m+n)的算法.与以前的算法相比,不管在p<相似文献   

基于数据预处理的并行分层聚类算法*

分层聚类技术在图像处理、入侵检测和生物信息学等方面有着极为重要的应用,是数据挖掘领域的研究热点之一。针对目前基于SIMD模型的并行分层聚类算法处理海量数据时效果不理想的问题,提出一种基于数据预处理的自适应并行分层聚类算法,在O((λn)2/p)的时间内对n个输入数据点进行聚类。其中1≤p≤n/log n,0.1≤λ≤0.3。将提出的算法与现有文献结论进行的性能对比分析表明,本算法明显改进了现有文献的研究结果。     

多输出弹性k-旋转对称布尔函数的存在性与构造

多输出布尔函数可由多个单输出布尔函数表示,在分组密码中有着广泛的应用.多输出k-旋转对称布尔函数(k-RSBF)是多输出旋转对称布尔函数(RSBF)的扩展.本文首先研究多输出旋转对称函数和多输出k-旋转对称函数的轨道分布情况,给出了计算两类函数中长度相同轨道个数的方法.其次研究了平衡多输出k-旋转对称布尔函数的存在性,给出了在选择合适的k的前提下,n=pr、n=2pr和n=2r时,平衡(n,m)k-RSBF的构造方法.之后研究弹性多输出k-旋转对称布尔函数的存在性,分别给出了r≥3,n=2r,2≤m≤2r-r,k=2时1阶弹性(n,m)k-RSBF的构造方法,以及p为奇素数,r≥2,n=pr,2≤m≤p-1,k=p时1阶弹性(n,m)k-RSBF的构造方法.最后我们还对两种方法得到的1阶弹性多输出k-旋转对称布尔函数进行仿真测试.     

SIMD-LA模型上的大整数乘法

本文提出了一种基于SIMD-LA模型的大整数乘法的算法,将分治策略与Karatsuba-Offman算法相结合改进了已有的算法.当使用p台处理器,大整数长度n＜=256p时,其时间复杂度为O(p);大整数长度n＞256p时,其时间复杂度为O(p[n]1.58/|p|+p).其时间复杂度比传统算法有了进一步的提高.     

Multisets排序的最优并行算法

排序是一个既有十分重要的理论意义又有广泛的实际应用价值的问题 ,其中 ,Multisets排序问题是指对只有k个不同关键字值的n个数据 (记录 )进行排序 ,0 相似文献   

最佳并行排列组合算法

本文给出两个新的最佳并行排列组合算法。这里所说的排列组合均指从n个元素中取m个元素的排列和组合处理。算法可运行于一种非常简单的并行计算模型上,它由k个同步运行的处理机构成,其中1≤k≤N,N为要处理的元素个数。当1≤k≤N/n,算法需O(「N/k」·h)时间。     

基于二叉树的反向Hash链遍历

提出了一种反向Hash链遍历的时间、空间复杂度优化算法.采用堆栈操作实现了高效的反向Hash链遍历,并将Hash链遍历过程映射到了二叉树的后序遍历过程,利用二叉树性质对存储和计算性能进行了理论化分析和证明.分析证明结果表明,遍历对长为n的反向Hash链时,算法只需要存储[lbn]+1个节点值,并且进行不多于[(lbn-/2+1)n次Hash计算次数.相比同类其他算法,该算法并不要求链长为2的整数次方.通过对算法进行基于k叉树(k≥3)的扩展,进一步将存储空间降低到[lo gk[(k-1)n+1],但总计算次数提高到[(-logk[(k-1)n+1]-1)k/2+1]n;通过在算法执行前先把Hash链平分为p段(p≥2),将总计算次数降低到[(lb(n/p)-/2+1)n,但是所需的存储空间提高到[(lb(n/p)+1)p.     

一种基于数据分块的快速原地归并算法

与其它排序算法相比,二路归并最适合于对两个有序子表进行排序.归并长度分别为m和n的两个有序子表,经典算法有两种.第一种算法完成归并需要○(m+n)的附加空间,○(m+n)次比较和移动.第二种算法是原地的,但完成归并需要○(m+n)次比较和○(m×n)次移动.经过长期研究,提出了一种基于数据分块的快速原地归并算法.新算法通过将数据分块、对数据块排序等方法最多用○((m+n)log2√m+n次比较和○((m+n)3/2)次移动完成两个有序子表的原地归并.实验证明,该算法与经典的原地算法相比,极大地降低了元素的移动次数和算法的运行时间.     

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.     

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     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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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