scholarly journals A Novel Process-Oriented Graph Storage for Dynamic Geographic Phenomena

2019 ◽  
Vol 8 (2) ◽  
pp. 100 ◽  
Author(s):  
Cunjin Xue ◽  
Chengbin Wu ◽  
Jingyi Liu ◽  
Fenzhen Su
Keyword(s):  
Graph Model ◽  
Oriented Graph ◽  
Spatial Evolution ◽  
Edge Structure ◽  
Oracle Spatial ◽  
Object A ◽  
Order Of Magnitude ◽  
Process Oriented ◽  
Point Line ◽  
Dynamic Geographic Phenomena

There exists a sort of dynamic geographic phenomenon in the real world that has a property which is maintained from production through development to death. Using traditional storage units, e.g., point, line, and polygon, researchers face great challenges in exploring the spatial evolution of dynamic phenomena during their lifespan. Thus, this paper proposes a process-oriented two-tier graph model named PoTGM to store the dynamic geographic phenomena. The core ideas of PoTGM are as follows. 1) A dynamic geographic phenomenon is abstracted into a process with a property that is maintained from production through development to death. A process consists of evolution sequences which include instantaneous states. 2) PoTGM integrates a process graph and a sequence graph using a node–edge structure, in which there are four types of nodes, i.e., a process node, a sequence node, a state node, and a linked node, as well as two types of edges, i.e., an including edge and an evolution edge. 3) A node stores an object, i.e., a process object, a sequence object, or a state object, and an edge stores a relationship, i.e., an including or evolution relationship between two objects. Experiments on simulated datasets are used to demonstrate an at least one order of magnitude advantage of PoTGM in relation to relationship querying and to compare it with the Oracle spatial database. The applications on the sea surface temperature remote sensing products in the Pacific Ocean show that PoTGM can effectively explore marine objects as well as spatial evolution, and these behaviors may provide new references for global change research.

Modeling Spatial Evolution

2018 ◽  
pp. 235-259 ◽  
Author(s):  
G. Jayanthi ◽  
V. Uma
Keyword(s):  
Temporal Relations ◽  
Spatial Evolution ◽  
Two Dimensional ◽  
Formal Representation ◽  
Effect Analysis ◽  
Spatial Features ◽  
Spatio Temporal ◽  
Point Line ◽  
Spatial Entities ◽  
Interval Logic

Geographic features in the real world are represented by spatial entities such as point, line, and area in two-dimensional surfaces. These features tend to evolve in time, thereby characterizing change in their physical identity, evolution into new species, thus describing geomorphological change of geographic features. These phenomena can be formalized using spatio-temporal relations. Formal representation of changing geographic (spatial) features is the interest of this chapter. Formal methods for representing the event and process that causes geomorphological change are presented. The formalization of geographic entities that are temporally and spatially related in a two-dimensional plane using the interval logic and spatial logic would facilitate the understanding of how modeling of space-time using spatio-temporal relations represents spatial evolution over time. Representation of temporal dynamism can be accomplished using various models. Modeling using spatio-temporal graph is more apt as it contributes to the cause-effect analysis.

scholarly journals Buffering Updates Enables Efficient Dynamic de Bruijn Graphs

2021 ◽  
Author(s):  
Jarno Alanko ◽  
Bahar Alipanahi ◽  
Jonathen Settle ◽  
Christina Boucher ◽  
Travis Gagie
Keyword(s):  
Graph Model ◽  
Biological Data ◽  
Theory And Practice ◽  
De Bruijn Graph ◽  
Efficient Manner ◽  
De Bruijn Graphs ◽  
Trade Offs ◽  
Order Of Magnitude ◽  
Efficient Data ◽  
De Bruijn

AbstractMotivationThe de Bruijn graph has become a ubiquitous graph model for biological data ever since its initial introduction in the later 1990s. It has been used for a variety of purposes including genome assembly (Zerbino and Birney, 2008; Bankevich et al., 2012b; Peng et al., 2012), variant detection (Alipanahi et al., 2020b; Iqbal et al., 2012), and storage of assembled genomes (Chikhi et al., 2016). For this reason, there have been over a dozen methods for building and representing the de Bruijn graph and its variants in a space- and time-efficient manner.ResultsAlthough there exists a plethora of space efficient data structures for storing the de Bruijn graph, the majority of them make a compression-mutability trade-off. In particular, with the exception of a few methods (Muggli et al., 2019; Holley and Melsted, 2020; Crawford et al., 2018), compressed and compact de Bruijn graphs do not allow for the graph to be efficiently updated, allowing for data to be added or deleted. The most recent compressed dynamic de Bruijn graph, (Alipanahi et al., 2020a), relies on dynamic bit vectors, which are slow in theory and practice. To address this shortcoming, we present BufBOSS which is a compressed dynamic de Bruijn graph that removes the necessity of dynamic bit vectors by buffering data that should be added or removed from the graph. We implement our method, which we refer to as BufBOSS, and compare its performance to Bifrost, DynamicBOSS, and FDBG. Our experiments demonstrate that BufBOSS achieves attractive trade-offs compared to other tools in terms of time, memory and disk, and has the best deletion performance by an order of magnitude out of all the tools that are able to perform deletions. Our implementation is available at https://github.com/jnalanko/[email protected]

scholarly journals Graph model development in the context of the grain cleaning machine

2018 ◽  
Vol 224 ◽  
pp. 05012 ◽  
Author(s):  
Andrey Butovchenko ◽  
Artem Dorochenko ◽  
Inna Kotelnikova
Keyword(s):  
Mathematical Model ◽  
Model Development ◽  
Graph Model ◽  
Oriented Graph ◽  
Control Factors ◽  
Schematic Layout ◽  
Cleaning Machine ◽  
General Mathematical Model ◽  
Output Characteristics ◽  
Working Bodies

Schematic layout and graph model of seed-cleaning unit are introduced in the article. Input vector, vector of control factors and vector of output characteristics are mentioned. The general mathematical model of purification section process is given. This model together with an oriented graph allows to conduct a program forecast and to find out the rational directions of increasing the efficiency of the work of individual working bodies and the system as a whole.

scholarly journals Integrating a Three-Level GIS Framework and a Graph Model to Track, Represent, and Analyze the Dynamic Activities of Tidal Flats

2021 ◽  
Vol 10 (2) ◽  
pp. 61
Author(s):  
Chao Xu ◽  
Weibo Liu
Keyword(s):  
Information Science ◽  
Graph Model ◽  
Integrated Approach ◽  
Geographic Information Science ◽  
Tidal Flats ◽  
Event Analysis ◽  
Cell Level ◽  
Depth Study ◽  
Spatiotemporal Scales ◽  
Dynamic Geographic Phenomena

Tidal flats (non-vegetated area) are soft-sediment habitats that are alternately submerged and exposed to the air by changeable tidal levels. The tidal flat dynamics research mainly utilizes the cell-level comparisons between the consecutive snapshots, but the in-depth study requires more detailed information of the dynamic activities. To better track, represent, and analyze tidal flats’ dynamic activities, this study proposes an integrated approach of a three-level Geographic Information Science (GIS) framework and a graph model. In the three-level GIS framework, the adjacent cells are assembled as the objects, and the objects on different time steps are linked as lifecycles by tracking the predecessor–successor relationships. Furthermore, eleven events are defined to describe the dynamic activities throughout the lifecycles. The graph model provides a better way to represent the lifecycles, and graph operators are utilized to facilitate the event analysis. The integrated approach is applied to tidal flats’ dynamic activities in the southwest tip of Florida Peninsula from 1984 to 2018. The results suggest that the integrated approach provides an effective way to track, represent, and analyze the dynamic activities of tidal flats, and it offers a novel perspective to examine other dynamic geographic phenomena with large spatiotemporal scales.

scholarly journals Constructive and object-oriented modeling text for detection of text borrowings

2019 ◽  
Vol 4 (123) ◽  
pp. 34-47
Author(s):  
Olena Serhiivna Kuropiatnykov
Keyword(s):  
Program Implementation ◽  
Main Idea ◽  
Graph Model ◽  
Object Oriented ◽  
Oriented Graph ◽  
Information Support ◽  
Edge Weight ◽  
Graph Representations ◽  
Text Model ◽  
Class Graph

The scientific community is encouraged to use such models and data structures as arrays of LERP-RSA (the longest expected duplicate array of reduced suffix templates), tag classifier-a model based on Stanford NER's three-class, structures based on DN-sequences, graph representations, etc. The following algorithms are used: GreedyString-Tiling, ARPAD, shingle, statistical methods, genetic algorithms, and others. It should also be noted that much attention is paid to morphological analysis and lemmatization, pre-processing of texts. Models and algorithms only partly have program realization.The purpose of this work is to develop a text model to identify borrowings and bring it to program implementation. The task is to develop the object-oriented model and program implementation of a graph text model, with the application of the problem of detection of borrowing. As well as obtaining timeframes for program implementation work for further evaluation of the possibility of its use in the academic environment.The main idea of the graph model is to present the text as a weighted oriented graph. The vertex weight is a character or sequence of characters. Edge weight is the set of numbers of paths into which the edge enters. To formalize the model will use the apparatus of constructive-synthesizing modeling. To create graphs, a constructor and its components are defined: carrier, signature, multiple statements of information support for design. Transformations are made for the constructor: specialization, interpretation and concretization.On the basis of this model, the object-oriented model is constructed. it includes three classes: vertex, graph and work .The object of class Work presents the text as a set of objects of class Graph. The correspondences between the components of the presented models are established.The object-oriented model is implemented by software. Data are given about the execution time of graph construction and texts comparison.At this stage, software implementation of the model has shown acceptable time performance. Further research in this direction is promising. Directions for improving the model and program are proposed.

scholarly journals A Process-Oriented Spatiotemporal Clustering Method for Complex Trajectories of Dynamic Geographic Phenomena

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 155951-155964
Author(s):  
Jingyi Liu ◽  
Cunjin Xue ◽  
Qing Dong ◽  
Chengbin Wu ◽  
Yangfeng Xu
Keyword(s):  
Clustering Method ◽  
Spatiotemporal Clustering ◽  
Process Oriented ◽  
Dynamic Geographic Phenomena ◽  
Complex Trajectories

2D XANES-XEOL mapping: observation of enhanced band gap emission from ZnO nanowire arrays

Nanoscale ◽  
2014 ◽  
Vol 6 (12) ◽  
pp. 6531-6536 ◽  
Author(s):  
Zhiqiang Wang ◽  
Xiaoxuan Guo ◽  
Tsun-Kong Sham
Keyword(s):  
Band Gap ◽  
Nanowire Arrays ◽  
Zno Nanowire ◽  
Edge Structure ◽  
X Ray ◽  
Zno Nanowire Arrays ◽  
Optical Luminescence ◽  
Order Of Magnitude ◽  
X Ray Absorption ◽  
Mapping Observation

Using two-dimensional X-ray absorption near-edge structure-X-ray excited optical luminescence (2D XANES-XEOL) spectroscopy, it is found that the band gap emission of ZnO nanowire arrays is substantially enhancedi.e.that the intensity ratio between the band gap and defect emissions increases by more than an order of magnitude when the excitation energy is scanned across the O K-edge. Possible mechanisms are discussed.

Space and Time Distribution of Hard X-Ray Emission in a Loop at the Beginning of a Flare

1994 ◽  
Vol 144 ◽  
pp. 275-277
Author(s):  
M. Karlický ◽  
J. C. Hénoux
Keyword(s):  
Time Distribution ◽  
Electron Bombardment ◽  
Spatial Evolution ◽  
Superthermal Electrons ◽  
Flare Loop ◽  
X Ray ◽  
Superthermal Electron ◽  
Flare Loops ◽  
Chromospheric Evaporation ◽  
Temporal And Spatial

AbstractUsing a new ID hybrid model of the electron bombardment in flare loops, we study not only the evolution of densities, plasma velocities and temperatures in the loop, but also the temporal and spatial evolution of hard X-ray emission. In the present paper a continuous bombardment by electrons isotropically accelerated at the top of flare loop with a power-law injection distribution function is considered. The computations include the effects of the return-current that reduces significantly the depth of the chromospheric layer which is evaporated. The present modelling is made with superthermal electron parameters corresponding to the classical resistivity regime for an input energy flux of superthermal electrons of 109erg cm−2s−1. It was found that due to the electron bombardment the two chromospheric evaporation waves are generated at both feet of the loop and they propagate up to the top, where they collide and cause temporary density and hard X-ray enhancements.

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