Adding Logical Operators to Tree Pattern Queries on Graph-Structured Data

As data are increasingly modeled as graphs for expressing complex relationships, the tree pattern query on graph-structured data becomes an important type of queries in real-world applications. Most practical query languages, such as XQuery and SPARQL, support logical expressions using logical-AND/OR/NOT operators to define structural constraints of tree patterns. In this paper, (1) we propose generalized tree pattern queries (GTPQs) over graph-structured data, which fully support propositional logic of structural constraints. (2) We make a thorough study of fundamental problems including satisfiability, containment and minimization, and analyze the computational complexity and the decision procedures of these problems. (3) We propose a compact graph representation of intermediate results and a pruning approach to reduce the size of intermediate results and the number of join operations -- two factors that often impair the efficiency of traditional algorithms for evaluating tree pattern queries. (4) We present an efficient algorithm for evaluating GTPQs using 3-hop as the underlying reachability index. (5) Experiments on both real-life and synthetic data sets demonstrate the effectiveness and efficiency of our algorithm, from several times to orders of magnitude faster than state-of-the-art algorithms in terms of evaluation time, even for traditional tree pattern queries with only conjunctive operations.Comment: 16 page

MEMBANGUN POHON MERENTANG MINIMUM DENGAN MENGGUNAKAN ALGORITMA PRIM

Graph is the method of discrete problem solution searching that was in the real world. Graph has much of concepts. The ones is Tree concept. Tree concept is being the significant and the popular concept because support to applies graph for a lot of branch of science. The application that use tree concept such as road away built project and railway track built project, built a computer network, etc. Tree is graph with undirected and connected. Being present graph with tree concept to solve problem by building graph become Minimum Spanning Tree. One of the algorithm which is used to built Minimum Spanning Tree is Prim algorithm. Prim algorithm is one of algorithm which is used to decide Minimum Spanning Tree from weighted graph and connected graph. Prim algorithm forms Minimum Spanning Tree step by step. Prim algorithm explores much of selection in every steps and product at least one Minimum Spanning Tre

Isotropic Dynamic Hierarchical Clustering

We face a need of discovering a pattern in locations of a great number of points in a high-dimensional space. Goal is to group the close points together. We are interested in a hierarchical structure, like a B-tree. B-Trees are hierarchical, balanced, and they can be constructed dynamically. B-Tree approach allows to determine the structure without any supervised learning or a priori knowlwdge. The space is Euclidean and isotropic. Unfortunately, there are no B-Tree implementations processing indices in a symmetrical and isotropical way. Some implementations are based on constructing compound asymmetrical indices from point coordinates; and the others split the nodes along the coordinate hyper-planes. We need to process tens of millions of points in a thousand-dimensional space. The application has to be scalable. Ideally, a cluster should be an ellipsoid, but it would require to store O(n2) ellipse axes. So, we are using multi-dimensional balls defined by the centers and radii. Calculation of statistical values like the mean and the average deviation, can be done in an incremental way. While adding a point to a tree, the statistical values for nodes recalculated in O(1) time. We support both, brute force O(2n) and greedy O(n2) split algorithms. Statistical and aggregated node information also allows to manipulate (to search, to delete) aggregated sets of closely located points. Hierarchical information retrieval. When searching, the user is provided with the highest appropriate nodes in the tree hierarchy, with the most important clusters emerging in the hierarchy automatically. Then, if interested, the user may navigate down the tree to more specific points. The system is implemented as a library of Java classes representing Points, Sets of points with aggregated statistical information, B-tree, and Nodes with a support of serialization and storage in a MySQL database.Comment: 6 pages with 3 example

The role played by exotic plants in urban ecosystems: comments on Spennemann, 2019

The article written by Dirk HR Spennemann, and published in the European Journal of Ecology, addresses the role played by a palm tree species native to the Canary Islands as food source for several frugivore species found in Australian cities. This palm tree bears fruit throughout the year; therefore, it is a reliable food source in winter and helps increasing wildlife support. Spennemann avoids the native versus exotic dogmatic simplism; instead, he assesses the palm tree species based on its positive environmental impact