Topological Queries Research Articles

PANDA: toward partial topology-based search on large networks in a single machine

A large body of research has focused on efficient and scalable processing of subgraph search queries on large networks. In these efforts, a query is posed in the form of a connected query graph. Unfortunately, in practice end users may not always have precise knowledge about the topological relationships between nodes in a query graph to formulate a connected query. In this paper, we present a novel graph querying paradigm called partial topology-based network search and propose a query processing framework called panda to efficiently process partial topology query (ptq) in a single machine. A ptq is a disconnected query graph containing multiple connected query components. ptqs allow an end user to formulate queries without demanding precise information about the complete topology of a query graph. To this end, we propose an exact and an approximate algorithm called sen-panda and po-panda, respectively, to generate top-kmatches of a ptq. We also present a subgraph simulation-based optimization technique to further speedup the processing of ptqs. Using real-life networks with millions of nodes, we experimentally verify that our proposed algorithms are superior to several baseline techniques.

Fusion Layer Topological Space Query Indexing For Uncertain Data Mining

Data uncertainty is an intrinsic property in different applications such as sensor network monitoring, object recognition, location-based services (LBS), and moving object tracking. The data mining methods are applied to the above mentionedapplications their uncertainty has to be handled to achieve the accurate query results. The several probabilistic algorithm estimates the location and control for each object but not effective in handling query processing in distributed environments. Probabilistic inverted indexing computes the lower bound and upper bound for a threshold keyword but fails to extend the technique on tackle the correlation. In order to overcome the issues in uncertain data mining, Fusion Layer Topological Space Query Indexing technique (FLTS)is introduced. Initially, the queries are articulated on any random subset of attributes in the uncertain data.The FLTS index technique answers the top-k queries competently. FLTS index correctlyshows in their dominant relationships andsignificantly reduces the number of tuple accessed through query processing by pruning redundant tuple based on two criterions such as layer point sort method and the record point sort method. Initially, layer point sort method is used in FLTS indexto sort out tuple totally on the combination of all attribute values of the tuple. Subsequently, each attributes values particularly used for rating the tuple using record point sort method. Therefore,the correlation is removed significantly. Through an analysis of the interaction of the two sorting methods, derive a fixed bound that reduces the number of tuple retrieved during query processing and obtaining the correct query results in distributed environments. An experimental result shows that the FLTS indexing technique improves the query retrieving efficiency, response time, memory consumption and scalability.

Using virtual topology operations to generate analysis topology

Virtual topology operations have been utilized to generate an analysis topology definition suitable for downstream mesh generation. Detailed descriptions are provided for virtual topology merge and split operations for all topological entities. Current virtual topology technology is extended to allow the virtual partitioning of volume cells and the topological queries required to carry out each operation are provided. Virtual representations are robustly linked to the underlying geometric definition through an analysis topology. The analysis topology and all associated virtual and topological dependencies are automatically updated after each virtual operation, providing the link to the underlying CAD geometry. Therefore, a valid description of the analysis topology, including relative orientations, is maintained. This enables downstream operations, such as the merging or partitioning of virtual entities, and interrogations, such as determining if a specific meshing strategy can be applied to the virtual volume cells, to be performed on the analysis topology description. As the virtual representation is a non-manifold description of the sub-divided domain the interfaces between cells are recorded automatically. This enables the advantages of non-manifold modelling to be exploited within the manifold modelling environment of a major commercial CAD system, without any adaptation of the underlying CAD model. A hierarchical virtual structure is maintained where virtual entities are merged or partitioned. This has a major benefit over existing solutions as the virtual dependencies are stored in an open and accessible manner, providing the analyst with the freedom to create, modify and edit the analysis topology in any preferred sequence, whilst the original CAD geometry is not disturbed. Robust definitions of the topological and virtual dependencies enable the same virtual topology definitions to be accessed, interrogated and manipulated within multiple different CAD packages and linked to the underlying geometry.

Evaluating Topological Queries in Linked Data Using DBpedia and GeoNames in Switzerland and Scotland

AbstractThis article explores the practicability and assesses the quality of searches for Wikipedia pages of topologically related administrative divisions in Switzerland and Scotland via Linked Data. To this end, the quality of searches in the English and German versions of DBpedia is compared, as is that of searches in GeoNames and DBpedia using DBpedia's links to GeoNames or a manually created list of links. In addition, the effects of updates to Swiss municipality borders in the English version of DBpedia on standard quality metrics are studied. It turns out that live searches are practicable with acceptable performance, but that the quality of searches in terms of recall and precision is acceptable only if DBpedia is queried via GeoNames and DBpedia's links to GeoNames are replaced by manually created links. Searches for Scottish unitary authority wards perform poorly for all approaches investigated. Recall and precision are strongly influenced by changes in municipality borders, with a relatively long latency suggesting that, at least in some cases, administrative changes propagate slowly into DBpedia. These results have important implications for those seeking to use location as a means to link data.

IBHM: index-based data structures for 2D and 3D hybrid meshes

We propose new topological data structures for the representation of 2D and 3D hybrid meshes, i.e., meshes composed of elements of different types. Hybrid meshes are playing an increasingly important role in all fields of modeling, because elements of different types are frequently considered either because such meshes are easier to construct or because they produce better numerical results. The proposed data structures are designed to achieve a balance between their memory requirements and the time complexity necessary to answer topological queries while accepting cells (elements) of different types. Additionally these data structures are easy to implement and to operate, because they are based on integer arrays and on basic arithmetic rules. A comparison with other existing data structures regarding their memory requirements and of the time complexities for the algorithms to answer general topological queries is also presented. The comparison shows that the overhead required to accept arbitrary cell types is small.

The Algorithm Design of Optical Fiber Topological Query

In order to achieve the query of the topology for optical fiber, transform the original problem into a node traverse problem on the graph by treating the optical fiber cable resources management system as graph model. Through the analysis of the physical structure of the optical cable and related business, reinvesting the nodes and edges on the graph with different meaning.Setting up some special edge to reduce the search for node,and the traditional traversal algorithm is improved by this strategy.At last the result of experiment for this algorithm design is shown on Google-Map.

IFC-Based Graph Data Model for Topological Queries on Building Elements

AbstractThe adoption of building information modeling (BIM) in construction has led to greater integration of architecture, engineering, construction/facility management (AEC/FM) stakeholders at the project design stage; the result being the incorporation of new complex tasks into construction applications. However, conventional two-dimensional (2D) and nonsemantic three-dimensional (3D) models cannot handle the topological analysis of 3D objects that is required by BIM, especially with regard to building elements. This article describes a new schema, termed the graph data model (GDM) that can be used to employ semantic information, to extract, analyze, and present the topological relationships among 3D objects in 3D space, and to perform topological queries faster. This GDM uses weighted graph principles for simplicity and incorporates an industry foundation classes (IFC)-based algorithm for automatic deduction of topological relationships. A prototype of GDM is implemented in a C# platform and verified ...

Topological mapping methods for α-helical bacterial membrane proteins--an update and a guide.

Integral membrane proteins with α-helical transmembrane segments (TMS) are known to play important and diverse roles in prokaryotic cell physiology. The net hydrophobicity of TMS directly corresponds to the observed difficulties in expressing and purifying these proteins, let alone producing sufficient yields for structural studies using two-/three-dimensional (2D/3D) crystallographic or nuclear magnetic resonance methods. To gain insight into the function of these integral membrane proteins, topological mapping has become an important tool to identify exposed and membrane-embedded protein domains. This approach has led to the discovery of protein tracts of functional importance and to the proposition of novel mechanistic hypotheses. In this review, we synthesize the various methods available for topological mapping of α-helical integral membrane proteins to provide investigators with a comprehensive reference for choosing techniques suited to their particular topological queries and available resources.

Research on the Distributed Spatial Topological Query Optimization Algorithm

Research on the Distributed Spatial Topological Query Optimization Algorithm

Distributed Spatial Data Fragmentation and Cross-Border Topological Join Optimization

PDF HTML阅读 XML下载 导出引用 引用提醒 分布式空间数据分片与跨边界拓扑连接优化方法 DOI: 10.3724/SP.J.1001.2011.03798 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金(40971232, 41023001); 国家高技术研究发展计划(863)(2007AA12Z201); 测绘遥感信息工程国家重点实验室开放基金; 测绘遥感信息工程国家重点实验室专项科研经费; 武汉大学优秀博士论文培育基金(2008-25) Distributed Spatial Data Fragmentation and Cross-Border Topological Join Optimization Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:研究分布式空间数据库(distributed spatial database,简称DSDB)中数据按区域分片时的跨边界片段拓扑连接查询问题,并提出相应的优化方法.首先研究了分布式环境下的空间数据的分片与分布,提出了空间数据分片的扩展原则:空间聚集性、空间对象的不分割性、逻辑无缝保持性.然后,将区域分割分片环境下的片段连接分为跨边界和非跨边界两类;同时,将拓扑关系分为两类,重点研究跨边界的两类片段拓扑连接.提出了跨边界空间片段拓扑连接优化的两个定理,并给出了证明.以此为基础,给出了跨边界空间拓扑连接优化规则,包括连接去除规则和连接优化转化规则.最后设计了详细的实验,对自然连接策略、半连接策略以及所提出的连接策略进行效率比较,结果表明,所提出的方法对跨边界连接优化有明显优势.因此,所提出的理论和方法可以用于分布式跨边界拓扑关系查询的优化. Abstract:This paper aims at explaining the cross-border topological join queries of spatial fragments of the zone fragmentation data in distributed spatial database (DSDB), and the optimizing methods for such queries are proposed. First, the fragmentation and distribution of spatial data in a distributed environment are discussed, and the extra principles for spatial data fragmentation are put forward, including spatial clustering, non-partitioning on spatial objects, and maintaining logical seamless. Then, the fragment joins in zone fragmentation are classified into two categories: cross-border join and non-cross-border join; the topological relationships are also classified into two categories. Thus, the emphasis is put on the two types of cross-border topological joins. Two theorems for cross-border topological join optimization are proposed and proved. Based on the theorems, the optimizing rules for cross-border spatial topological join are given, including the removing rules and the transforming rules of fragment joins. Finally, tests are designed to compare three join strategies that include Na?ve join strategy, semi-join strategy and the proposed strategies. The results show that the proposed methods greatly improve the cross-border join optimizing efficiency. Therefore, the theorems and methods proposed in this work can be applied to the optimization of distributed cross-border spatial topological queries. 参考文献 相似文献 引证文献

Topological Queries on Graph-structured XML Data: Models and Implementations

In many applications, data is in graph structure, which can be naturally represented as graph-structured XML. Existing queries defined on tree-structured and graph-structured XML data mainly focus on subgraph matching, which can not cover all the requirements of querying on graph. In this paper, a new kind of queries, topological query on graph-structured XML is presented. This kind of queries consider not only the structure of subgraph but also the topological relationship between subgraphs. With existing subgraph query processing algorithms, efficient algorithms for topo- logical query processing are designed. Experimental results show the efficiency of implementation algorithms. Keywords—XML, Graph Structure, Topological query.

Stylized Vector Art from 3D Models with Region Support

AbstractWe describe a rendering system that converts a 3D meshed model into the stylized 2D filled‐region vector‐art commonly found in clip‐art libraries. To properly define filled regions, we analyze and combine accurate but jagged face‐normal contours with smooth but inaccurate interpolated vertex normal contours, and construct a new smooth shadow contour that properly surrounds the actual jagged shadow contour. We decompose region definition into geometric and topological components, using machine precision for geometry processing and raster‐precision to accelerate topological queries. We extend programmable stylization to simplify, smooth and stylize filled regions. The result renders 10K‐face meshes into custom clip‐art in seconds.

Reasoning about geological space: Coupling 3D GeoModels and topological queries as an aid to spatial data selection

Topological relationships between geological objects are of great interest for mining and petroleum exploration. Indeed, adjacency, inclusion and intersection are common relationships between geological objects such as faults, geological units, fractures, mineralized zones and reservoirs. However, in the context of 3D modeling, actual geometric data models used to store those objects are not designed to manage explicit topological relationships. For example, with Gocad© software, topological analyses are possible but they require a series of successive manipulations and are time consuming. This paper presents the development of a 3D topological query prototype, TQuery, compatible with Gocad© modeling platform. It allows the user to export Gocad© objects to a data storage model that regularizes the topological relationships between objects. The development of TQuery was oriented towards the use of volumetric objects that are composed of tetrahedrons. Exported data are then retrieved and used for 3D topological and spatial queries. One of the advantages of TQuery is that different types of objects can be queried at the same time without restricting the operations to voxel regions. TQuery allows the user to analyze data more quickly and efficiently and does not require a 3D modeling specialist to use it, which is particularly attractive in the context of a decision-making aid. The prototype was tested on a 3D GeoModel of a continental red-bed copper deposit in the Silurian Robitaille Formation (Transfiguration property, Québec, Canada).

Assessing the Scaffold Diversity of Screening Libraries

Medicinal chemists have traditionally realized assessments of chemical diversity and subsequent compound acquisition, although a recent study suggests that experts are usually inconsistent in reviewing large data sets. To analyze the scaffold diversity of commercially available screening collections, we have developed a general workflow aimed at (1) identifying druglike compounds, (2) clustering them by maximum common substructures (scaffolds), (3) measuring the scaffold diversity encoded by each screening collection independently of its size, and finally (4) merging all common substructures in a nonredundant scaffold library that can easily be browsed by structural and topological queries. Starting from 2.4 million compounds out of 12 commercial sources, four categories of libraries could be identified: large- and medium-sized combinatorial libraries (low scaffold diversity), diverse libraries (medium diversity, medium size), and highly diverse libraries (high diversity, low size). The chemical space covered by the scaffold library can be searched to prioritize scaffold-focused libraries.

Linearization and Completeness Results for Terminating Transitive Closure Queries on Spatial Databases

We study queries to spatial databases, where spatial data are modeled as semi-algebraic sets, using the relational calculus with polynomial inequalities as a basic query language. We work with the extension of the relational calculus with terminating transitive closures. The main result is that this language can express the linearization of semialgebraic databases. We also show that the sublanguage with linear inequalities only can express all computable queries on semilinear databases. As a consequence of these results, we obtain a completeness result for topological queries on semialgebraic databases.

Development of a Temporal Extension to Query Travel Behavior Time Paths Using an Object-Oriented GIS

An essential requirement to better understand activity-based travel behavior (ABTB) at the disaggregate level is the development of a spatio-temporal model able to support queries related to activities of individuals or groups of individuals. This paper describes the development and implementation of a temporal extension to a geographic information system (GIS) object-oriented model for the modeling of the time path and the retrieval of its event chaining. In this approach, time path is formulated as a totally time ordered set composed by activity events and trip events, themselves organized into time ordered sets. As sets, the time path and its components can be searched using their respective indexes. A series of methods were built that implement temporal predicates as an interface to temporally query the database. A set of positional operator methods were also designed that transform temporal topological queries into retrieval functions based on set ordering indices. Taken together, the temporal predicates and the positional operator methods define a temporal query extension that meets the retrieval needs of an ABTB database.

On first-order topological queries

One important class of spatial database queries is the class of topological queries , that is, queries invariant under homeomorphisms. We study topological queries expressible in the standard query language on spatial databases, first-order logic with various amounts of arithmetic. Our main technical result is a combinatorial characterization of the expressive power of topological first-order logic on regular spatial databases.

Querying Spatial Databases via Topological Invariants

The paper investigates the use of topological annotations (called topological invariants) to answer topological queries in spatial databases. The focus is on the translation of topological queries against the spatial database into queries against the topological invariant. The languages considered are first-order on the spatial database side, and fixpoint+counting, fixpoint, and first-order on the topological invariant side. In particular, it is shown that fixpoint+counting expresses precisely all the ptime queries on topological invariants; if the regions are connected, fixpoint expresses all ptime queries on topological invariants.

3D Topological modeling and visualisation for 3D GIS

Beyond Virtual Reality, 3D Geographical Information Systems should provide efficient spatial analysis tools able to use all capabilities of the third dimension, and a visualization that could operate on the results of queries. To address these issues, this paper presents a fully 3D topological model that was implemented in an object-oriented database management system. That prototype uses a 1 : 5,000 scale database where the problems of abstraction and symbolisation arise, and allows a set of semantic, geometrical and topological queries. The results can be visualized after several transformations on some objects of the database to make them more significant.

Topological Queries in Spatial Databases

We studytopological queriesover two-dimensional spatial databases. First, we show that the topological properties of semi-algebraic spatial regions can be completely specified using a classical finite structure, essentially the embedded planar graph of the region boundaries. This provides aninvariantcharacterizing semi-algebraic regions up to homeomorphism. All topological queries on semi-algebraic regions can be answered by queries on the invariant whose complexity is polynomially related to the original. Also, we show that for the purpose of answering topological queries, semi-algebraic regions can always be represented simply as polygonal regions. We then study query languages for topological properties of two-dimensional spatial databases, starting from the topological relationships between pairs of planar regions introduced by Egenhofer. We show that the closure of these relationships under appropriate logical operators yields languages which arecompletefor topological properties. This provides a theoreticala posteriorijustification for the choice of these particular relationships. Unlike the point-based languages studied in previous work on constraint databases, our languages are region based—quantifiers range over regions in the plane. This yields a family of languages, whose complexity ranges fromNCto undecidable. Another type of completeness result shows that the region-based language of complexityNCexpresses precisely the same topological properties as well-known point-based languages.