二叉树的一种新存储结构

本文提出了一种可简单、高效地表示二叉树的存储结构。该结构：（１）显著地提高了寻找给定结点的父／兄结点等基本操作的时间效率，达到Ｏ（１），高于传统结构树下的效率；（２）使遍历操作不再显式或隐式地使用辅助堆栈；（３）提高了存储结构中指针字段利用率；（４）保持其它基本操作的效率不变。     

体数据内部结构绘制技术及其在3维医学图像分析中的应用

首先基于集合论方法对体数据内部结构进行分析(内部结构是指被外部物体遮挡或隐藏而不能从外部直接看到的物体或结构),从而给出了内部结构绘制技术的功能要求。基于此功能要求,提出了基于内部结构区域的体绘制技术来分析体数据内部结构的方法。基于内部结构区域的体绘制技术之所以能够分析体数据内部结构是因为该方法把体数据分为两个子集:内部结构区域(或称局部区域)和周围区域。内部结构区域提供了深入体数据内部的机制,通过对内部结构区域的交互,用户可以分析体数据内部的任意区域,从而达到对体数据内部结构和整个体数据的综合理解。该方法还可对内部结构进行量化分析从而提高用户分析体数据的质量。最后,该方法用于分析3维医学图像以显示其在实际应用中的强大功能。实验结果表明,该方法对3维医学图像中的内部结构可以有效地进行定性和定量分析。     

Canonical density control

The Sparse Table is a data structure for controlling density in an array which was first proposed in 1981 and has recently reappeared as a component of cache-oblivious data structures. All existing variants of the Sparse Table divide the array into blocks that have a calibrator tree above them. We show that the same amortized complexity can be achieved without this auxiliary structure, obtaining a canonical data structure that can be updated by conceptually simpler algorithms.     

Primitives for the manipulation of three-dimensional subdivisions

Algorithms for manipulating three-dimensional cell complexes are seldom implemented due to the lack of a suitable data structure for representing them. Such a data structure is proposed here along with the primitive operations necessary to make it useful. Applications of the structure are also given.This work was supported in part by the National Science Foundation under Grant No. DCR85-05517.     

Algorithms for BD trees

Database applications often require a sophisticated class of storage structures in order to answer different types of queries efficiently. This often dictates that the file should be organized on multiple keys. Several storage structures have been proposed to satisfy these needs. Most are generalizations of the storage structures used for managing one-dimensional data. Recently, a new storage structure, called the BD tree, was proposed to manage multidimensional data. This structure has good dynamic characteristics. This paper presents algorithms for the BD tree to perform insertion, deletion, and to answer exact match, partial match and range queries. In addition, some experimental evidence is presented that suggests that BD trees have good dynamic characteristics.     

一种多结构及文本融合的网络表征方法

网络表征通过对网络结构的深度学习得到节点的矢量表征,挖掘网络中潜在的信息,是社会计算中的一种重要降维方法。针对一种融合了网络中的文本和结构的、基于矩阵分解的网络表征方法TADW,首先分析并讨论了文本属性矩阵在矩阵分解式中的位置对网络表征效果的影响,并对此方法进行了优化;在此基础上,提出了一种融合关系结构、交互结构和文本属性的社交网络表征方法。在多个数据集上的实验结果表明,该方法在多分类任务中优于其他经典网络表征方法。     

复杂网络社团的谱分检测方法

为有效地检测复杂网络中的社团结构,优化模块密度函数,展示模块密度函数怎样被优化框定到谱分聚类问题,提出一种谱分算法,进一步对该算法进行时间复杂度分析。在一个经典的真实世界网络中检验该算法,并与基于模块密度的直接核方法及基于模块函数的谱分方法做比较。特别地,当网络中社团结构变得模糊时,实验结果显示,该谱分算法在发现复杂网络社团上是有效的。     

基于蚀刻结构的强度调制型光纤传感器􀀂

本文介绍了有着蚀刻结构的光纤传感器在应变测量以及薄结构振动测量中的应用和检测机理 .并且在非对称蚀刻结构的光纤曲率传感器的基础上提出了分布式光纤模态曲率传感器研究     

二谱分聚类的复杂网络社团检测方法

近年来,复杂网络中的社团发现越来越受到研究人员的关注并且许多方法被提了出来。为有效地检测复杂网络中的社团结构,优化了评估与发现社团的模块密度函数(即D值)。通过模块密度的优化进程,证明了模块密度函数能写成模块密度矩阵迹的最大化表达形式。利用模块密度矩阵的谱分分解,提出了一种新的二谱分的聚类检测复杂网络社团方法。在LFR标准人工模型网络中验证了二谱分方法的有效性。实验结果显示这种新的方法在发现复杂网络社团上有较高的准确性。     

桥梁结构状态参数监测技术研究现状

桥梁的自然老化、劣化将会影响其安全与正常使用,甚至造成重大的人员伤亡和财产损失,已成为交通运输部门关注的问题。为了有效维护桥梁和确保其安全运行,监测桥梁结构的关键状态参数对于全面及时反映桥梁工作状态和进一步开展安全性评估极为重要。综述了桥梁结构的应变、挠度、振动等关键状态参数监测技术的研究进展,并分析了这些监测技术的基本原理、性能、应用范围,同时,对未来桥梁结构状态参数监测的发展提出了建议。     

核k-means聚类检测复杂网络社团算法

为揭示复杂系统中的结构与功能之间的联系,复杂网络中的社团发现成为一项最基本的任务.最近,李等人提出了一种用来评估社团质量的函数,称之为模块密度函数(即D值),并利用一个核矩阵给出了模块密度目标函数与核k-means方法之间的等价性.基于这种等价性,通过过渡操作的核矩阵来优化模块密度函数并提出了一种新的核k-means算法.实验结果表明,这种算法在发现复杂网络社团上是有效的.     

含假结RNA二级结构类的图语法

用最小自由能法预测RNA二级结构是NP困难问题,其根本原因是假结的存在。近几年的预测算法都针具有一定结构特征的假结寻找多项式时间算法进行预测。论文针对RNA二级结构图提出一种图语法,该语法由初始结构图集和重写规则集构成,用重写规则在初始结构图上的不断重写得到的结构图都是该语法的语言。分析了5个主流RNA二级结构预测算法的目标集,给出它们的图语法,使得目标集的结构特征一目了然,目标集间的真包含关系也通过图语法直观地体现出来。     

Robustness study of emerged communities from exchanges in peer-to-peer networks

The study of emerged community structure is an important challenge in networks analysis. In fact, several methods have been proposed in the literature to statistically determine the significance of discovered structures. Nevertheless, most of existing analysis models consider only the structural aspect of emerged communities. We are interested in studying the robustness of emerged communities in peer-to-peer (P2P) networks. More precisely, we consider the emerged communities in the induced graph by all the exchanges in these networks. Hence, rather than examining the robustness only on the structural properties of the graph, we will focus on the parameters that allow the emergence of community structures. In fact, perturbing these parameters might destroy most of the obtained properties at the emerged level. To the best of our knowledge, robustness of networks has never been considered from this angle before. In this paper, we study the impact of perturbing the content and the profile of nodes on the emerged communities in P2P networks. We show how these alterations affect both structure and information supported by the emerged structures.     

激光选区熔化工艺晶格支撑结构快速建模

针对激光选区熔化成型工艺中的支撑结构,提出一种晶格单元自动填充生成支撑 的快速建模方法。首先,分别对两种典型晶格支撑结构--杆架结构和孔隙结构的组成单元实 现参数化造型,并建立支撑结构数字化模型;其次,设计实现杆件单元和孔隙单元的造型算法; 最后,提出一种单元自然生长算法,实现对支撑空间快速填充。实例结果表明,晶格结构可以 对不同类型金属产品结构实现有效稳定支撑;相比实体材料,平均可以节省 72%的材料用量, 具有重要的工程意义。     

带有大型挠性网状天线航天器的鲁棒H∞控制方法

针对带有大型挠性网状天线航天器存在的挠性结构不确定性问题,提出了基于比例微分(PD)结构滤波器的鲁棒H∞双层反馈控制方法,第1层采用经典的PD+结构滤波器,确保刚体部分双积分环节稳定,第2层在提取第1层标称模型后,给出通用加权函数,通过构造增广模型得到鲁棒H∞控制器.该控制器结构简单,适合工程应用.通过仿真表明,本方法相对于传统PID+结构滤波器方法能够快速稳定三轴姿态;当结构参数变化较大且三轴姿态偏置为动态时变时,有可能导致传统方法失稳,而本方法具有较强的鲁棒适应性,仍能完成航天器天线的指向任务.     

汉语V+V序列关系识别研究

“V+V”是现代汉语中的常见结构,能够形成兼语、连动等多种完全不同的句法结构,给句法和语义解析造成困难。针对“V+V”形成的句法结构类型和序列关系识别问题,设计并制定了一套语料库标注规范,以解决语料库中存在的“V+V”结构的嵌套标注问题,并据此构建起一个包含5 381个兼语句子、7 987个连动句子,以及1 212个兼语连动嵌套句子的“V+V”语料库。提出一个基于BiLSTM-CRF和多头注意力机制的模型,能够同时识别结构中的多个动词和名词的句法、语义角色。相比于以往只研究单项识别兼语或者连动结构,该模型不仅可以同时识别兼语结构、连动结构,还可以解决兼语连动嵌套结构的识别问题。实验结果表明：该方法能够很好地解决“V+V”序列关系的识别问题,在测试集语料上达到92.12%的F1值。     

Characterizing History Independent Data Structures

We consider history independent data structures as proposed for study by Naor and Teague. In a history independent data structure, nothing can be learned from the memory representation of the data structure except for what is available from the abstract data structure. We show that for the most part, strong history independent data structures have canonical representations. We provide a natural alternative definition of strong history independence that is less restrictive than Naor and Teague and characterize how it restricts allowable representations. We also give a general formula for creating dynamically resizing history independent data structures and give a related impossibility result.     

An empirical performance comparison of some variations of thek-d Tree andBD tree

Database applications very often require a sophisticated class of storage structures in order to answer different types of queries efficiently. This often dictates that the file should be organized on multiple keys. Several storage structures have been proposed to satisfy these needs. Most of these are a generalization of the storage structures used for managing one-dimensional data. Thek-d tree is one such example and it is a natural generalization of the standard one-dimensional binary search tree. Recently, a new storage structure, called theBD tree, was proposed to manage multidimensional data. This structure has good dynamic characteristics. Several variations are possible on the basick-d tree structure. This paper studies the performance implications of three variations. Further, it provides an empirical performance comparison of thek-d tree andBD tree in database applications.     

An efficient decoding technique for Huffman codes

We present a new data structure for Huffman coding in which in addition to sending symbols in order of their appearance in the Huffman tree one needs to send codes of all circular leaf nodes (nodes with two adjacent external nodes), the number of which is always bounded above by half the number of symbols. We decode the text by using the memory efficient data structure proposed by Chen et al. [Inform. Process. Lett. 69 (1999) 119-122].     

The d-deap*: a fast and simple cache-aligned d-ary deap

This paper presents a generalized and cache-aligned implicit version of the deap, called d-deap* that utilizes cache memory efficiently. The d-deap* is based on a tree structure that may be mapped into a cache-aligned array without padding. This results in a match between node indexes and array indexes as well as good cache utilization. Experimental results show that the d-deap* clearly outperforms the symmetric min-max heap and deap structures proposed earlier for double-ended priority queues.