A database system of mechanical components based on geometric and topological similarity. Part I: representation

A database of mechanical components is an important issue for some manufacturing activities such as cost estimation, process planning, and design by case-based reasoning. In this paper, we give the representation scheme of the CAD model in such a database. Components are represented using attributed graphs in which the nodes correspond to the surfaces of the component and the links correspond to the edges of the component. The graph is based on the standard for the exchange of product information (STEP) physical file of the component. STEP file should be unique for a single component regardless of the underlying CAD system. The process of creating the graph of a component constitutes two sub-tasks: (i) importing the CAD model from the CAD system in STEP format and (ii) transforming the STEP data into attributed graph-based representation. The graph and its attributes describe the topology of the component completely together with some geometric data that are not dependent on any coordinate system such as surface type and curve type. These geometric data are helpful in the retrieval and matching processes in the database.     

基于本体集成的资源共享平台

资源共享是许多数据整合项目需要完成的首要任务。本体作为知识共享的有力工具，近来被广泛应用于数据整合项目中。针对共享的资源已存在各自对应本体的情况，提出了一个基于本体集成的资源共享平台实现方法。重点讨论了本体集成过程中不一致性的检查、处理问题和概念层次统一的问题，并以实际项目为例，介绍了所研究的方法如何运用于实际项目中。     

Efficient algorithms for single- and two-layer linear placement of parallel graphs

This paper outlines an algorithm for optimum linear ordering (OLO) of a weighted parallel graph with O(n log k) worst-case time complexity, and O(n + k log(n/k) log k) expected-case time complexity, where n is the total number of nodes and k is the number of chains in the parallel graph. Next, the two-layer OLO problem is considered, where the goal is to place the nodes linearly in two routing layers minimizing the total wire length. The two-layer problem is shown to subsume the maxcut problem and a befitting heuristic algorithm is proposed. Experimental results on randomly generated samples show that the heuristic algorithm runs very fast and outputs optimum solutions in more than 90% instances.     

基于知识图的汉语基本名词短语分析模型

本文提出了一种基于知识图的汉语baseNP分析模型。它以知识图为知识表示方法,利用《知网》为语义知识资源,采用以语义为主、语法为辅的策略,先为短语中的每一个实词构造“词图”,然后合并“词图”而组成“短语图”,最后得到一个关于汉语baseNP结构信息和语义信息的知识图。因此它不仅分析了汉语baseNP结构的内部句法关系,而且分析了汉语baseNP结构成分间的语义关系并以知识图的形式表示出了这种语义关系。实验结果表明这个模型对于汉语baseNP的分析是有效的。     

High level synthesis of integrated heterogeneous pipelined processing elements for DSP applications

A technique for scheduling and processor allocation leading to the synthesis of integrated heterogeneous pipelined processing elements, implementing digital signal processing applications, is proposed. The proposed technique achieves efficient hardware implementations at the logic-level by minimizing the number of processing units used, without compromising the rate and delay optimality criteria.

The proposed algorithm is found to outperform algorithms resulting in homogeneous implementations, as it gives schedules with lower iteration periods, requires less hardware resources, and has lower time complexity at design time. In comparison with the already existing heterogeneous algorithms, the proposed algorithm produces schedules of lower time complexity and lower iteration period for some applications. The optimal performance of the proposed algorithm has been verified on several benchmarks.     

Finding hidden independent sets in interval graphs

We design efficient competitive algorithms for discovering hidden information using few queries. Specifically, consider a game in a given set of intervals (and their implied interval graph G) in which our goal is to discover an (unknown) independent set X by making the fewest queries of the form “Is point p covered by an interval in X?” Our interest in this problem stems from two applications: experimental gene discovery with PCR technology and the game of Battleship (in a 1-dimensional setting). We provide adaptive algorithms for both the verification scenario (given an independent set, is it X?) and the discovery scenario (find X without any information). Under some assumptions, these algorithms use an asymptotically optimal number of queries in every instance.     

二分图中含大圈的 2―因子(英文)

本文给出了均衡二分图有一个2-因子恰含 k 个大圈的度条件。设 G = (V1,V2;E) 是一个二分图,满足 |V1| = |V2| = n ≥ sk,其中 s ≥ 3 和 k ≥ 1 是两个整数。如果图 G 的最小度至少为 (1 ? 1/s)n + 1,那么 G 有一个2-因子恰含 k 个圈使得每个圈长至少为 2s。     

一种分析闲聊协议的数学方法

该文总结了目前基于随机闲聊(Gossip)的可靠多播协议,这类协议也被称为流行病风格的多播协议。在此研究基础之上建立了随机闲聊的一般数学模型,给出了闲聊的两个基本要素。该文的数学方法基于随机图理论,通过引入相变理论找到了闲聊的扇出系数和模型可靠性之间的数学关系,同时分析了闲聊的通讯开销以及闲聊网络中结点的负载情况。仿真结果肯定了该文的结论。     

Elementary Statistics

Fractional two-level factorial designs are often used in the early stages of an investigation to screen for important factors. Traditionally, 2 ^n-k fractional factorial designs of resolution III, IV, or V have been used for this purpose. When the investigator is able to specify the set of nonnegligible factorial effects, it is sometimes possible to obtain an orthogonal design with fewer runs than a standard textbook design by searching within a wider class of designs called parallel-flats designs. The run sizes in this class of designs do not necessarily need to be powers of 2. We discuss an algorithm for constructing orthogonal parallel-flats designs to meet user specifications. Several examples illustrate the use of the algorithm.