Applications of lattice theory to graph decomposition

It is shown that the set of multitree classes equipped with a partial order is a lattice called a multitree lattice. This multitree lattice in fact is a geometric lattice. Since there is a one-to-one correspondence between a multitree class and an element of the multitree lattice, the trees of a composite of subgraphs can be generated without duplications by the set union of the Cartesian products of the multitree classes of the subgraphs, which form a maximal independent set.     

Iterative procedure for generating trees and directed trees

An iterative procedure for generating trees and directed trees is described. The procedure will not introduce any redundancies, duplications, or cancellations of terms, and is readily adaptable for a digital computer. With minor modifications, the process may also be used to generate 2-trees and directed 2-trees, and for the evaluation of the numbers of trees, directed trees, 2-trees and directed 2-trees efficiently.     

Combined forward error control and packetized zerotree waveletencoding for transmission of images over varying channels

One method of transmitting wavelet based zerotree encoded images over noisy channels is to add channel coding without altering the source coder. A second method is to reorder the embedded zerotree bitstream into packets containing a small set of wavelet coefficient trees. We consider a hybrid mixture of these two approaches and demonstrate situations in which the hybrid image coder can outperform either of the two building block methods, namely on channels that can suffer packet losses as well as statistically varying bit errors.     

一种计算随机流网络可靠性的新算法

提出了一种计算随机流网络可靠性的新方法。通过一定的规则生成网络的状态树，使得每一个分支都是全序集合。在生成状态树的同时搜索每一个分支，对状态采用基于割集的方法进行判断。每个分支上的最小的有效状态就是网络的d-下界点。求得所有的d-下界点，进而求出网络的可靠性。     

低损耗退火质子交换光波导弯曲损耗分析

波导弯曲部分是出现波导辐射损耗最大的地方，所以在设计弯曲波导时，有必要对波导的这部分进行优化设计处理。该文利用电磁场理论，完成对余弦形分支光波导弯曲部分损耗的数学建模．最后针对铌酸锂基片上，用退火质子交换法生成的分支光波导进行数值仿真。     

电子电路噪声的岔集谱分析法

本文阐明了目前电路噪声理论的不完善性,提出了电子电路岔集谱分析法,使噪声计算的精度和效率有显著提高。作者编制并调试成功了基于此方法的电子电路噪声性能分析和低噪声设计程序,文末给出了实例结果。与实验结果的比较,说明了本文提出方法的正确性。     

Modeling of geometric properties of loblolly pine tree and standcharacteristics for use in radar backscatter studies

An approach is presented to physically describe the tree and canopy components within loblolly pine forests in studies of microwave backscattering from forested canopies. The approach is based on a set of algorithms which describe the biomass characteristics of individual trees using measurements of tree diameter, height, and canopy depth. These algorithms predict bole, branch, and needle biomass; number, sizes, and orientations of primary and smaller branches; and number and density of needle clumps. Methods are discussed to aggregate the individual tree measurements into stand measurements (i.e., measurements per unit area). The results of the model clearly show how biomass distribution between tree components and canopy layers varies as a function of stand age for loblolly pines. The results also show the approach can be used to predict changes in the branch size and orientation within the canopy as a function of stand age, both on an individual tree basis as well as an entire stand basis     

INDUCTION OF DECISION TREES BASED ON A FUZZY NEURAL NETWORK

Based on a fuzzy neural network, the letter presents an approach for the induction of decision trees.The approach makes use of the weights of fuzzy mappings in the fuzzy neural network which has been trained.It can realize the optimization of fuzzy decision trees by branch cutting, and improve the ratio of correctness and efficiency of the induction of decision trees.     

Event-tree analysis using binary decision diagrams

This paper is concerned with ETA (event-tree analysis) where the branch point event causes are defined using fault trees. Attention is on the nontrivial situation where there are dependencies amongst the branch point events. The dependencies are due to component-failures in more than one of the fault trees. In these situations the analysis methods based on traditional FTA (fault-tree analysis) are inaccurate and inefficient. The inaccuracies are not consistent across the outcome events. If frequency predictions calculated in this way are then used in a risk assessment then the relative risks would be distorted and could lead to resources being used inappropriately to reduce the overall risk. A new approach using BDD (binary decision diagram) is described which addresses these deficiencies     

电网络的回路岔集分析法

本文定义了描述网络图回路与节点关联状况的矩阵D,定义了回路岔集和回路岔集矩阵。提出并证明了回路节点矩阵与节点矩阵的乘积等于回路岔集矩阵的定理。定义了回路岔集导纳矩阵,假设回路岔集电压矢量作为中间计算量,导出了回路岔集方程,并提出了对电网络的回路岔集分析法。     

基于蒙特卡洛低压电力线信道容量研究

为了有利于设计适当的低压电力线通信设备使之达到更好的有效的数据传输,对低压电力线网络建立模型,优化低压传输信道,对低压电力信道中的脉冲噪声给出了噪声模型.在此基础上研究了支路的数量、支路所带的负载以及支路长度等对信道容量的影响,在负载相同的条件下随着支路数的增加信道容量呈非线性下降趋势,其中室内信道容量下降最大达12兆比特,低压信道容量下降最大达23兆比特,支路负载以及支路长度对信道容量影响不大.结论是低压电力信道容量随着网络拓扑结构的变化呈动态变化.     

The number of different possible compact codes (Corresp.)

For a source with a given numberqof messages and an unspecified set of probabilities, the numberX(q)of non-trivially different compact codes that are possible increases in a predictable fashion asqincreases. Distinct binary compact codes ofqmessages correspond to distinct oriented binary trees withqterminal nodes. The theorem of this correspondence shows that, by using a recursion relation, and given that there is one compact code tree forq = 2, all compact code trees for anyq >2can be automatically constructed. This is done by splitting, for all integerss geq 1, sbottom level nodes of all compact code trees which haveq - sterminal nodes and which end insor more bottom level nodes.     

基于LCS的特征树最大相似性匹配网页去噪算法

提出了一种基于LCS的特征树最大相似性匹配网页去噪算法.通过将目标网页和相似网页转化为特征树,并将特征树映射为一个特征节点序列,利用LCS算法能获得最长子序列全局最优解的特点,找出两棵特征树之间的不同节点作为候选集,并对候选集进行聚集评分找出网页重要内容块.给出了算法的原型系统,并对每一个模块的实现做了详尽的描述.     

Methods for Probabilistic Analysis of Noncoherent Fault Trees

Four methods for the probabilistic analysis of s-coherent fault trees are investigated concerning their applicability to noncoherent fault trees. The inclusion-exclusion and min-max bounds can be extended to noncoherent fault trees, while the minimal cut (path) set bounds cannot. When a fault tree is modularized, the application of the min-max bounds or the inclusion-exclusion upper bound to both the modules and the organizing structure function yields the same bounds that are obtained without modular decomposition. If the organizing structure function or the modules are simple enough, exact calculations can be performed at either level to give an improved bound.     

The estimated cost of a search tree on binary words

The problem of constructing a binary search tree for a set of binary words has wide applications in computer science, biology, mineralogy, etc. Shannon considered a similar statement in his optimal coding theorem. It is NP-complete to construct a tree of minimum cost; therefore, the problem arises of finding simple algorithms for constructing nearly optimal trees. We show that there is a simple algorithm for constructing search trees sufficiently close to the optimal tree on average. By means of this algorithm we prove that for the optimal tree the average number of bits to be checked is near to its natural lower bound, i.e., the binary logarithm of the number of given words: their difference is less than 1.04     

Computing error probabilities of multilevel modulation codes

We describe a computational algorithm for the evaluation of error probabilities of multilevel modulation codes. This is based on the derivation of a trellis cataloging the words of the component codes and of a suitable set of branch labels depending on the channel on which the transmission takes place (additive white Gaussian noise channel, fading channel with or without channel state information). The error probability is upper bounded by the transfer function of this trellis, which is derived in closed form.     

Automated anatomical labeling of the bronchial branch and its application to the virtual bronchoscopy system

This paper describes a method for the automated anatomical labeling of the bronchial branch extracted from a three-dimensional (3-D) chest X-ray CT image and its application to a virtual bronchoscopy system (VBS). Automated anatomical labeling is necessary for implementing an advanced computer-aided diagnosis system of 3-D medical images. This method performs the anatomical labeling of the bronchial branch using the knowledge base of the bronchial branch name. The knowledge base holds information on the bronchial branch as a set of rules for its anatomical labeling. A bronchus region is automatically extracted from a given 3-D CT image. A tree structure representing the essential structure of the extracted bronchus is recognized from the bronchus region. Anatomical labeling is performed by comparing this tree structure of the bronchus with the knowledge base. As an application, we implemented the function to automatically present the anatomical names of the branches that are shown in the currently rendered image in real time on the VBS. The result showed that the method could segment about 57% of the branches from CT images and extracted a tree structure of about 91% in branches in the segmented bronchus. The anatomical labeling method could assign the correct branch name to about 93% of the branches in the extracted tree structure. Anatomical names were appropriately displayed in the endoscopic view.     

Allocation of light splitters in all-optical WDM networks with sparse light splitting capabilities

In all-optical WDM networks, splitters at branch nodes are used to realize multicast trees. The problem of selecting a subset of nodes to place the splitters such that certain performance measure is optimized is called the splitter placement problem. This paper studies the splitter placement problem in all-optical WDM networks in which a light-forest is used to realize a multicast connection. The goal is to place a given number of splitters in the network such that the average per link wavelength resource usage of multicast connections is minimized. An upper bound and a lower bound on the per link average wavelength resource usage are derived. Two splitter placement methods are proposed for this problem. The proposed splitter methods are shown to yield significant lower average wavelength resource usage than the random placement method. One of the methods is shown to produce near minimum average wavelength resource usage.     

移动对象全局K最接近邻居查询研究

基于两个对象在一段时间内的范围距离度量,给出了一种新的时空查询形式-全局最接近邻居查询。该查询检索移动对象在一段时间内范围距离最小的运动对象。通过考察查询和连续最接近邻居之间关系,给出了一个基本查询处理算法。根据数据对象集的运动性不同,精化了运动和静止数据集下的全局距离的定义,并对R树结构索引的数据集给出了裁减、更新和访问启发式规则。采用分支界定技术和给出的启发式规则,设计了迭代的深度优先和基于堆的最好优先的查询处理算法。大量的实验表明,最好优先的查询处理算法具有突出的性能。