Characterizing sets of data structures by the connectivity relation

A formalism based on the directed graph connectivity relation is presented, in which a first-order predicate calculus notation is used with the purpose of defining sets of data structures and characterizing the structural operations on them. The formalism is designed so as to facilitate the proof that the intended operations on instances of a given set of data structures are correct, in the sense that they do not violate the structural form of the data.     

Transformations of fuzzy graphs specified by <Emphasis Type="Italic">FD</Emphasis>-grammars

The categorical approach is proposed to formalize transformations of FD-graphs that consist of networks of distributed components whose nodes are specified by fuzzy graphs. Necessary and sufficient conditions are formally defined for FD-graph transformations that do not violate structure integrity and can be constructed componentwise. FD-grammars that generalize fuzzy graph grammars are proposed to describe the admissible transformations of FD-graphs. __________ Translated from Kibernetika i Sistemnyi Analiz, No. 2, pp. 129–147, March–April 2007.     

Multi-level association rules and directed graphs for spatial data analysis

We propose a methodology that upgrades the methods of the Lagrangian analysis of surface sea-water parcels. This methodology includes data mining with efficient visualization techniques, namely, spatial–temporal association rules and multi-level directed graphs with different levels of space and time granularity. In the resulting multi-level directed graphs we can intertwine knowledge from various disciplines related to oceanography (in our application) and perform the mining of such graphs. We evaluate the proposed methodology on Lagrangian tracking of virtual particles in the velocity field of the numerical model called the Mediterranean Ocean Forecasting Model (MFS). We describe an efficient algorithm based on label propagation clustering, which finds cycles and paths in multi-level directed graphs and reveals how the number and size of the cycles depend on the seasons. In addition, we offer three interesting results of the visualization and mining of such graphs, that is, the 12 months periodicity of the exchange of water masses among sea areas, the separation of Mediterranean Sea circulation in summer and winter situations, obtained with the hierarchical clustering of multi-level directed graphs, and finally, with visualization with multi-level directed graphs we confirm the reversal of sea circulation in the Ionian Sea over the last decades. The aforementioned results received a very favorable evaluation from oceanographic experts.     

Toward a mathematical theory of graph-generative systems and its applications

This paper presents some formal generative specifications for describing the graph languages consisting of the sets of directed graphs with labeled arcs. Some mathematical results are introduced. In addition, we consider applications to specification technique for data structures and complexity measure of computer software. Finally, directions for future research are indicated.     

基于有向图的二进制文件结构化比较机制研究

通过对二进制文件结构化比较方法的研究,提出了基于有向图的二进制文件结构化比较方法及实现算法.和基于指令比较的二进制文件比较方法相比,二进制文件结构化比较方法更注重二进制文件在逻辑结构上的变化,而且更加简单.     

一种基于有向图的工作流测试方法

已有工作流测试方法在测试完备性和充分性方面存在不足。针对此问题文章对有向图工作流模型进行扩展,提出了一种新的工作流测试方法,设计并实现了其算法。该方法能够自动生成完备且充分的测试路径和测试用例。实例验证该方法有效。     

Verification of conceptual schemata based on hybrid object-oriented and logic paradigm

Contemporary conceptual modelling languages are concerned with the representational adequacy of knowledge about a universe of discourse and with the efficient organization of this knowledge in structures that help overcome the problems of size and complexity in the modelled reality. In the paper it is argued that a conceptual modelling language should also facilitate the verification of captured requirements by exercising the conceptual schemata derived from the use of such a language. A conceptual modelling language is presented that is based on a hybrid representation scheme that makes use of object-oriented and logic approaches, and it is shown how this language can be used to verify requirements during the development of information systems.     

基于大数据时代的数据可视化应用分析

如今随着数据采集、存储和数据分析技术飞速发展,大幅度降低了数据储存和处理的成本,我们即将步入一个大数据时代。大数据时代的改革将海量数据处理变为可能,而且大幅降低了处理成本,促使越来越多跨专业学科的人才投入到大数据的开发应用中来。如何才能让大型数据集变得简单和易于理解,可视化无疑是最有效的途径。对大数据背景下的数据可视化应用展开研究,将有助于我们发展和创新数据可视化技术。     

基于十字链表的多刚体系统的数据存储

针对多刚体系统数据存储的不足,对多刚体系统的结构图与图论的有向图之间的关系进行了研究,提出了一种新的基于十字链表的链式存储模型.该存储模型不但较好地解决了复杂多刚体系统的存储问题,而且充分满足了在存储物理多刚体系统时的结构正确性和数据完备性要求,避免了非树形多刚体向树形多刚体的回路切除转换,使多刚体系统在数学建模与数据存储方面达到高度一致.     

基于多中间件的数据集成方案

为了实现分布的异构数据集成,解决"信息孤岛"问题,结合J2EE架构的优势和许多成功的数据集成方案,提出了基于数据访问中间件、消息中间件、数据源集成中间件的数据集成方案.详细讲述了该集成方案的架构和实现,实现结果表明该方案明显提高了数据集成的效率.最后,结合最新技术发展趋势对数据集成的研究前景做出了展望.     

Defining the abstract syntax of visual languages with advanced graph grammars—A case study based on behavior trees

Diagrammatic visual languages can increase the ability of engineers to model and understand complex systems. However, to effectively use visual models, the syntax and semantics of these languages should be defined precisely. Since most diagrammatic visual models that are currently used to specify systems can be described as (directed) typed graphs, graph grammars have been identified as a suitable formalism to describe the abstract syntax of visual modeling languages. In this article, we investigate how advanced graph-transformation techniques, such as conditional, structure-generic and type-generic graph-transformation rules, can help to improve and simplify the specification of the abstract syntax of a visual modeling language. To demonstrate the practicability of an approach that unifies these advanced graph-transformation techniques, we define the abstract syntax of behavior trees (BTs), a graphical specification language for functional requirements. Additionally, we provide a translational semantics of BTs by formalizing a translation scheme to the input language of the SAL model checking tool for each of the graph-transformation rules.     

A study on multi-dimensional products of graphs and hybrid logics

In this work, we address some issues related to products of graphs and products of modal logics. Our main contribution is the presentation of a necessary and sufficient condition for a countable and connected graph to be a product, using a property called intransitivity. We then proceed to describe this property in a logical language. First, we show that intransitivity is not modally definable and also that no necessary and sufficient condition for a graph to be a product can be modally definable. Then, we exhibit a formula in a hybrid language that describes intransitivity. With this, we get a logical characterization of products of graphs of arbitrary dimensions. We then use this characterization to obtain two other interesting results. First, we determine that it is possible to test in polynomial time, using a model-checking algorithm, whether a finite connected graph is a product. This test has cubic complexity in the size of the graph and quadratic complexity in its number of dimensions. Finally, we use this characterization of countable connected products to provide sound and complete axiomatic systems for a large class of products of modal logics. This class contains the logics defined by product frames obtained from Kripke frames that satisfy connectivity, transitivity and symmetry plus any additional property that can be defined by a pure hybrid formula. Most sound and complete axiomatic systems presented in the literature are for products of a pair of modal logics, while we are able, using hybrid logics, to provide sound and complete axiomatizations for many products of arbitrary dimensions.     

基于有向图建模的航天器自动化测试研究与实现

为了提高航天器测试效率及测试质量,研究了在无法给出航天器数学模型的情况下利用知识定义方法实现自动化测试的原理.通过对航天器静态测试和动态测试任务的分析,建立了航天器测试任务中测试业务的数学表示模型.基于有向图理论,建立了航天器测试过程的基本模型,提出了一种形式简单、易于理解、便于应用的表格方式航天器自动化测试语言(SATL),给出了SATL应用示例,开发了航天器自动化测试软件(SATS).SATL和SATS成功应用于"神舟"飞船及多颗卫星各阶段测试,实际应用表明了该方案具有较强的工程实用性.     

基于Pi-演算的扩展有向图工作流模型及验证

为了加强工作流模型对业务流程的描述能力,提出了一种扩展有向图工作流模型及其验证方法.针对基于有向图工作流模型的不足,提出了扩展有向图工作流模型,并给出了该模型的定义和图形符号描述.在用Pi-演算准确描述扩展有向图工作流模型的基础上,给出了用Pi-演算分析和验证扩展有向图工作流模型正确性的方法.最后,结合实验对扩展有向图工作流模型及验证方法进行了仔细分析,实验结果表明了该工作流模型及验证方法的有效性和正确性.     

Semi-supervised classification and betweenness computation on large, sparse, directed graphs

This work addresses graph-based semi-supervised classification and betweenness computation in large, sparse, networks (several millions of nodes). The objective of semi-supervised classification is to assign a label to unlabeled nodes using the whole topology of the graph and the labeling at our disposal. Two approaches are developed to avoid explicit computation of pairwise proximity between the nodes of the graph, which would be impractical for graphs containing millions of nodes. The first approach directly computes, for each class, the sum of the similarities between the nodes to classify and the labeled nodes of the class, as suggested initially in [1] and [2]. Along this approach, two algorithms exploiting different state-of-the-art kernels on a graph are developed. The same strategy can also be used in order to compute a betweenness measure. The second approach works on a trellis structure built from biased random walks on the graph, extending an idea introduced in [3]. These random walks allow to define a biased bounded betweenness for the nodes of interest, defined separately for each class. All the proposed algorithms have a linear computing time in the number of edges while providing good results, and hence are applicable to large sparse networks. They are empirically validated on medium-size standard data sets and are shown to be competitive with state-of-the-art techniques. Finally, we processed a novel data set, which is made available for benchmarking, for multi-class classification in a large network: the U.S. patents citation network containing 3M nodes (of six different classes) and 38M edges. The three proposed algorithms achieve competitive results (around 85% classification rate) on this large network-they classify the unlabeled nodes within a few minutes on a standard workstation.     

基于XML的异构数据交换模型的研究

基于XML的异构数据交换系统通过XML提供通用数据格式,在异构数据源间信息交换的模型中使用XML文档作为中间文件.由于以往的交换系统只提取出了少部分用户自定义完整性约束,因此提出一种新的关系模式和XML模式相互转换的方法.在转换过程中,重新定义了关系模式的通用模型,从而保证了数据的完整性.通过实验证明了该转换方法的可行...     

Decremental 2- and 3-connectivity on planar graphs

We study the problem of maintaining the 2-edge-, 2-vertex-, and 3-edge-connected components of a dynamic planar graph subject to edge deletions. The 2-edge-connected components can be maintained in a total ofO(n logn) time under any sequence of at mostO(n) deletions. This givesO(logn) amortized time per deletion. The 2-vertex- and 3-edge-connected components can be maintained in a total ofO(n log² n) time. This givesO(log² n) amortized time per deletion. The space required by all our data structures isO(n). All our time bounds improve previous bounds.This work was partially supported by the ESPRIT II Basic Research Actions Program of the EC under Project ALCOM II (contract No. 7141) and Project ASMICS. A preliminary version of this paper appears in [12].Partially supported by a CNR Fellowship. Work done while the author was visiting Columbia University.On leave from IBM T. J. Watson Research Center, Yorktown Heights, NY 10598, USA.     

A data dependence test based on the projection of paths over shape graphs

We propose a data dependence detection test based on a new conflict analysis algorithm for C codes which make intensive use of recursive data structures dynamically allocated in the heap. This algorithm requires two pieces of information from the code section under analysis (a loop or a recursive function): (i) abstract shape graphs that represent the state of the heap at the code section; and (ii) path expressions that collect the traversing information for each statement. Our algorithm projects the path expressions on the shape graphs and checks over the graphs to ascertain whether one of the sites reached by a write statement matches one of the sites reached by another statement on a different loop iteration (or on a different call instance in a recursive function), in which case a conflict between the two statements is reported. Although our algorithm presents exponential complexity, we have found that in practice the parameters that dominate the computational cost have very low values, and to the best of our knowledge, all the other related studies involve higher costs. In fact, our experimental results show reductions in the data dependence analysis times of one or two orders of magnitude in some of the studied benchmarks when compared to a previous data dependence algorithm. Thanks to the information on uncovered data dependences, we have manually parallelized these codes, achieving speedups of 2.19 to 3.99 in four cores.     

一种基于有向图模型的数据广播终端缓存算法

数据广播是将宽带数据广播到智能终端的一项技术,在数字电视领域被广泛采用.越来越多的数据广播前端采用基于浏览器的数据广播,网页内容在这些前端被打包成TS流,经过数据广播信道传输到终端,由集成在机顶盒内的浏览器解析,最终被显示到电视屏幕.本文分析了基于浏览器的数据广播系统,在前端为待传输的树型文件系统构建了有向图模型,并将其转移矩阵播发到终端;在终端提出了基于有向图的LRU-G缓存算法.仿真实验表明,相比LRU和LIX,LRU-G能够有效提高命中率,降低等待时间,改善用户体验.