椭圆曲线数字签名研究综述

椭圆曲线数字签名是一种重要的数字签名，本文首先概述了现代密码技术的现状。接着介绍了椭圆曲线数字签名；最后分析了椭圆曲线签名算法的优点；最后提出了现存问题和预测了发展方向。     

自动造区的“导弹”的算法

已知平面上的若干曲线，这些曲线可能相互相交并形成若干区域。问题是如何从这些已知曲线来计算这些区域，文中从面向对象的角度出发，这对一问题进行了研究并提出了一种合理算法，因该算法利用曲线的方向及位置关系直接造区，搜索过程如发射的导弹一般可直接命中目标，故形象地称之为导弹算法     

汽车车身零件图纸的自动标注方法

本文提出了一种汽车零件图纸的自动标注方法，给出根据被标注曲线的曲率与延伸方向确定标注间隔与标注方向的算法。     

Hilbert曲线的快速生成算法设计与实现

研究了Hilbert曲线的特征和现有经典算法，依据二分技术提出了一种全新的空间填充曲线生成算法，算法按照复制的思想将具有“形”特征的曲线问题转化为具有“数”特征的矩阵问题．因此对曲线的操作就转化为对矩阵的运算，而矩阵运算不用考虑绘制曲线方向问题，也不用考虑曲线始点和终点．实验结果表明，该算法比经典的L系统算法提高了将近1倍的速度，有意义的是，该算法为并行计算大型空间填充曲线提出了一种方案。     

利用人工神经网络推断曲线间的空间关系

在利用综合信息进行矿产预测中，航磁和重力图件一阶导数极值线（曲线）分别反映了地质体的磁性和密度断裂，为了推断不高深度地质体的断裂构造、产状和规模，需要对不同延拓高度、不同方向的航磁和重力曲线进行比较，以推断它们之间的空间关系是否相似，只有相似的曲线所反映的断裂才是可靠的，为了能够自动进行这种推理分析，给出了曲线间空间关系推理的神经网络方法，并且与传统的曲线间空间关系的判断方法进行了比较，结果表明，利用神经网络方法进行曲线间空间关系分析所得到的判断结果与权威地质专家的判断非常吻合，在实际应用中取得了令人满意的效果。     

轮廓环的方向及内外轮廓的判定

本文对轮廓环方向的确定问题及内外轮廓的判别问题进行了研究，提出了基于图形极限的内外轮廓判定模型和基于曲线积分与格林公式的轮廓方向确定模型。论述了各自的基本思想及算法实现。     

基于参数速度逼近的等距曲线有理逼近

该文提出了曲线的参数速度逼近问题 ,指出等距曲线逼近的关键在于参数速度的逼近 ,并用两种方式来实现它 .首先 ,以法矢方向曲线的控制顶点模长为 Bézier纵标构造 Bernstein多项式 ,以它来逼近曲线的参数速度 ,给出了相应的几何方式的等距逼近算法 ,进一步利用法矢方向曲线的升阶获得了高精度逼近 .其次 ,基于参数速度的 L egendre多项式逼近和插值区间端点的 Jacobi多项式逼近 ,导出了保持法矢平移方向的两种代数方式的等距有理逼近算法 .     

基于导数法的变电站接地网方向检测

为了测量接地网的拓扑结构，必须对接地网方向进行准确的检测。为此提出了一种用于高压变电站接地网方向检测的导数方法。当电流通过垂直导线注入电网时，磁通密度的分布垂直于地球表面。通过对垂直导线定心圆进行三阶求导，增加曲线的切线斜率来减小峰宽，克服了峰宽较大造成的假峰现象，精确地得到了与接地导线方向相吻合的主峰，从而运用接地支路方向相对应的峰值完成方向检测。利用Comsol Multiphysics 5.0进行仿真，结果表明，该方法计算接地网方向精度高，并且峰宽与圆半径成反比关系，增大圆半径可以进一步精确接地网方向的检测。     

曲面造型技术综述

曲面造型技术是计算机辅助设计（CAD）和计算机图形学（CG）中最为活跃、同时也是最为关键的学科分支之一，它随着CAD／CAM技术的发展而不断完善、渐趋成熟。1963年，美国Boeing飞机公司的Ferguson首先提出了将曲线曲面表示为参数的矢函数方法。他最早引入参数三次曲线，构造了组合曲线和由四角点的位置矢量及两个方向的切矢定义的Ferguson双三次曲面片。他所采用的曲线曲面的参数形式从此成为曲线曲面设计中进行形状数学描述的标准形式。1964到1967年，美国麻省理工学院的Coons提出了一个具有一般性的曲面描述方法，给走围成封闭曲线…     

椭圆曲线密码体制及其安全性研究

椭圆曲线密码是一种高安全性、高效率的公钥密码,它基于更高难度的椭圆曲线离散对数问题(ECDLP),介绍了椭圆曲线的基本知识和椭圆曲线密码体制,并分析了其安全性,展望了密码学未来的发展方向。     

The impact of mapping wander on the performance of SDH AU-4 and TU-3 uniform pointer processors

Pointer processors in Synchronous Optical Networks (SONET)/Synchronous Digital Hierarchy (SDH) networks may be placed into three categories: fixed threshold, adaptive threshold modulation and uniform. Fixed threshold pointer processors produce gapped pointer sequences during SONET/SDH holdover mode, when one or more node's clock has lost its synchronization reference, as a result of the periodic effects of the SONET/SDH frame overhead bytes. These gapped pointer sequences cause mapping wander in the underlying Plesiochronous Digital Hierarchy (PDH) payloads. Uniform pointer processors can smooth the gapped pointer effects caused by the Synchronous Transport Module (STM), Administrative Unit (AU) and Tributary Unit (TU) overhead bytes. However, uniform pointer processors cannot remove the additional gapped pointer effects caused by the Virtual Container (VC) overhead bytes. Mathematical analysis and simulation results, for fixed threshold pointer processors in SDH networks where VC-3 uses TU-3 to transport an E3-rate PDH payload or VC-4 uses AU-4 to transport an E4-rate PDH payload, illustrate the wander caused by the gapped pointer effects. A proposed uniform pointer processor algorithm shows the residual mapping wander caused by the VC-3 and VC-4 overhead bytes. Finally, a lower bound on the Maximum Time Interval Error (MTIE) that can be achieved with a uniform pointer processor is calculated for these two cases.     

蛋白质数据库中匹配间隙序列标签的自动机算法

对于肽和蛋白质的分析鉴别,串联质谱（MS／MS）是极其重要的方法。解释MS／MS数据的一种方法是de novo序列,它正变得越来越准确和重要了。但de novo序列通常只能准确地判定序列的一部分,而对于不确定的部分只能通过“质量间隙”来表示,我们称这样部分确定的序列为间隙序列标签。对于蛋白质的分析鉴别,当在数据库中查询一个间隙序列标签时,其中确定的部分应与数据库蛋白质序列完全匹配,而对于每一个质量间隙也应匹配一个氨基酸子串,这些氨基酸子串的质量和应与质量间隙的质量和相等。在这种情况之下,标准的串匹配算法已经不再适用。在本文中,我们将提出一个新的且有效的算法,用以在蛋白质数据库中找到与间隙序列标签所匹配的序列。     

Adaptively shortened pull down menus: location knowledge and selection efficiency

Adaptively shortened pull down menus, as introduced by Microsoft with the ‘personalized menus’ in Office 2000? and assumed to speed up menu selection, are examined. Displacement of items in this adaptively changing menu is argued to conflict with the user's location knowledge, leading to increased selection times and error rates. In a controlled experiment with 31 subjects, a standard menu was compared with a shortened and a gapped menu variant. The gapped menu variant served to distinguish effects from displacement and effects resulting from reduced item number. Selection times and error rates were smaller for the standard menu than for the shortened variant. The gapped menu, whilst it has longer distances, was faster than the shortened menu, but slower than the standard menu. According to our findings, the assumption that adaptively shortened pull down menus facilitate menu selection is weakened.     

Maximal and minimal representations of gapped and non-gapped motifs of a string

The problems of finding maximal and minimal equivalent representations for gapped and non-gapped motifs as well as finding motifs that characterize a fixed set of occurrence locations for a given string are studied. We apply two equivalence relations on representations. The first one is the well-known occurrence-equivalence of motifs. The second equivalence is introduced for patterns of occurrence locations, to characterize such patterns by motifs. For both equivalences, quadratic-time algorithms are given for finding a maximal representative of an equivalence class. Finding a minimal representative is shown to be NP-complete in both cases. For non-gapped motifs suffix-tree-based linear-time algorithms are given for finding maximal and minimal representatives. Maximal (minimal) gapped motifs are composed of blocks that are maximal (minimal) non-gapped motifs, maximal and minimal non-gapped motifs thus making up a small basis for all motifs. The implied bound on the number of gapped motifs that have a fixed number of non-gapped blocks is also given.     

An interval-based temporal relational calculus for events with gaps

Abstract

Traditional interval-based representations of time assume interval convexity, i.e., that intervals are uninterrupted. This assumption makes it difficult to represent the common sense notion of a single event with ‘gaps’. Having a representation of this species of event contributes favorably to the ability of the human or machine to solve certain tasks, such as planning or database retrieval. This paper defines two kinds of discourse and knowledge object which comprise collections of convex intervals. Although other researchers have suggested the need for a relaxation of the assumption of convexity in event representation, there has been no attempt to offer a concise representation of gapped events. The formulation employed here to introduce gapped events is an extension of James Allen's interval-based approach to time representation. Allen's calculus of thirteen binary relations defined between two convex intervals is generalized to a matrix of binary relations between each pair of subintervals of pairs of non-convex intervals. A primary goal of this paper is to show that this extension of the interval-based approach increases the expressive power of the calculus, while retaining its computational advantages.     

Searching for gapped palindromes

We study the problem of finding, in a given word, all maximal gapped palindromes verifying two types of constraints, that we call long-armed and length-constrained   palindromes. For each of the two classes, we propose an algorithm that runs in time O(n+S)$O(n+S)$ for a constant-size alphabet, where S$S$ is the number of output palindromes. Both algorithms can be extended to compute biological gapped palindromes within the same time bound.     

基于多层抽象的程序行为模型及异常检测研究

在入侵检测领域,对程序行为的异常分析始终缺乏高效的短周期模型,现有模型对程序行为的抽象能力非常有限。为此,首先提出一种新的、具备充分自描述能力的模式:间隙变长频繁短序列模式(GV模式),该模式涵盖描述程序行为的顺序、选择和循环3种基本结构;然后给出GV模式挖掘算法以及基于GV模式库的系统调用流程图模型。实验表明,基于新模型的异常检测算法简单高效,在保持高检测率的前提下具有较低的检测开销和误检率,具备了实时检测能力。     

Tree slicing: Finding intertwined and gapped clones in one simple step

Most of software nowadays contain code duplication that leads to serious problems in software maintenance. A lot of different clone detection approaches have been proposed over the years to deal with this problem, but almost all of them do not consider semantic properties of the source code. We propose to reinforce traditional tree-based clone detection algorithm by using additional information about variable slices. This allows to find intertwined/gapped clones on variables; preliminary evaluation confirms applicability of our approach to real-world software.     

基于闭合有间隔频繁子序列的点击流聚类

对网站日志文件中记录的点击流序列聚类可以发现用户使用模式,从而对用户归类。而传统聚类方法面临着难以提取点击流中有代表性的特征向量以及点击流及其特征向量存在数据稀疏性的问题。针对上述情况,提出一种基于闭合有间隔频繁子序列模式挖掘的点击流聚类方法。该方法从点击流中提取子序列模式的频繁支持度,构建特征向量,利用基于双向映射欧氏距离的模糊距离度量判断向量间相似度,增强BIRCH聚类算法对点击流数据的聚类效果。     

Error diagnosis in a tutoring system for the conjugation and spelling of Dutch verbs

A flexible knowledge-based tutoring system for the conjugation and spelling of Dutch verbs is described. The program, called Het Spelraam, is intended to communicate procedural knowledge about the spelling of verb forms to students with elementary spelling knowledge. The student has to fill in gapped sentences. If an incorrect answer is entered, the system locates the point where the student deviated from the path through the spelling algorithm that is leading to the correct answer. From that particular point the student is guided through the spelling algorithm. The error diagnosis techniques applied are described in detail. Het Spelraam is a commercial product which is used in both schools and language-training institutes. Results from initial evaluations are promising.