VRGQ

2021 ◽  
Vol 55 (1) ◽  
pp. 11-20
Author(s):  
Xiaolin Jiang ◽  
Chengshuo Xu ◽  
Rajiv Gupta
Keyword(s):  
Power Law ◽  
Second Step ◽  
Graph Analytics ◽  
Large Power ◽  
Graph Query ◽  
Query Result ◽  
Small Set ◽  
Graph Queries ◽  
Global Nature ◽  
Step Algorithm

While much of the research on graph analytics over large power-law graphs has focused on developing algorithms for evaluating a single global graph query, in practice we may be faced with a stream of queries. We observe that, due to their global nature, vertex specific graph queries present an opportunity for sharing work across queries. To take advantage of this opportunity, we have developed the VRGQ framework that accelerates the evaluation of a stream of queries via coarsegrained value reuse. In particular, the results of queries for a small set of source vertices are reused to speedup all future queries. We present a two step algorithm that in its first step initializes the query result based upon value reuse and then in the second step iteratively evaluates the query to convergence. The reused results for a small number of queries are held in a reuse table. Our experiments with best reuse configurations on four power law graphs and thousands of graph queries of five kinds yielded average speedups of 143×, 13.2×, 6.89×, 1.43×, and 1.18×.

Graph analytics and visualization for cyber situational understanding

2021 ◽  
pp. 154851292110513
Author(s):  
Steven Noel ◽  
Stephen Purdy ◽  
Annie O’Rourke ◽  
Edward Overly ◽  
Brianna Chen ◽  
...  
Keyword(s):  
Natural Language ◽  
Detailed Analysis ◽  
Ad Hoc ◽  
Query Language ◽  
Software Components ◽  
Proof Of Concept ◽  
Graph Analytics ◽  
The Core ◽  
Interactive Visualizations ◽  
Graph Queries

This paper describes the Cyber Situational Understanding (Cyber SU) Proof of Concept (CySUP) software system for exploring advanced Cyber SU capabilities. CySUP distills complex interrelationships among cyberspace entities to provide the “so what” of cyber events for tactical operations. It combines a variety of software components to build an end-to-end pipeline for live data ingest that populates a graph knowledge base, with query-driven exploratory analysis and interactive visualizations. CySUP integrates with the core infrastructure environment supporting command posts to provide a cyber overlay onto a common operating picture oriented to tactical commanders. It also supports detailed analysis of cyberspace entities and relationships driven by ad hoc graph queries, including the conversion of natural language inquiries to formal query language. To help assess its Cyber SU capabilities, CySUP leverages automated cyber adversary emulation to carry out controlled cyberattack campaigns that impact elements of tactical missions.

Geometric Containment Analysis for Rotational Parts

2004 ◽  
Author(s):  
Mukul Karnik ◽  
Satyandra K. Gupta ◽  
Edward B. Magrab
Keyword(s):  
Material Removal ◽  
New Products ◽  
Second Step ◽  
The Third ◽  
Rank Orders ◽  
Rotational Part ◽  
Rotational Parts ◽  
Step Algorithm ◽  
The Cost

This paper describes a system and underlying algorithms to perform geometric containment analysis to determine if a newly designed rotational part can be manufactured from a part in an existing database of rotational parts. Only material removal of the database part is considered in order to obtain the newly designed part from the database part. The system uses a three-step algorithm to test for containment. The first step analyzes feasibility of containment using bounding cylinders. If the bounding cylinder of the query part is bigger than the part in the database, then the database part cannot contain the query part and it is eliminated from consideration. The second step analyzes feasibility of containment by ignoring off-axis features. Any part that fails to satisfy containment at this stage is eliminated from consideration. The third step analyzes the remaining parts from the database for feasibility of containment by including the off-axis features. Finally, the system rank-orders all the database parts that can contain the query part based on their volume differences with the query part. The system described in this paper can be used to find an existing part from which to manufacture a newly designed part. This capability is expected to significantly reduce proliferation of parts, to improve manufacturing responsiveness, and to reduce the cost of new products.

scholarly journals Generalized Newtonian flow analysis in the microchannel manufactured by SLA considering nano-scale stair effect

2022 ◽  
Vol 14 (1) ◽  
pp. 168781402110704
Author(s):  
Jianhua Sun ◽  
Hai Gu ◽  
Jie Zhang ◽  
Yuanyuan Xu ◽  
Guoqing Wu ◽  
...  
Keyword(s):  
Power Law ◽  
Flow Analysis ◽  
Surface Force ◽  
Layer By Layer ◽  
Large Power ◽  
Manufacturing Method ◽  
Nano Scale ◽  
The Stability ◽  
Boltzmann Method ◽  
Power Law Index

SLA (stereolithography), as a rapid and accurate additive manufacturing method, can be used to mold the microchannel. The stair effect is inevitable when the part is printed layer by layer, which has an important influence on the printing performance. In the current work, the power-law flow in the microchannel with nano-scale stairs manufactured by SLA is simulated and investigated. To improve the stability caused by the non-Newtonian behavior, a modified lattice Boltzmann method (LBM) is proposed and validated. Then, a series of simulations are conducted and analyzed, the results show that both the stair effect and power-law index are important factors. The stairs on the surface force the streamlines to be curved and increase the outlet velocity. In addition, different power-law indexes result in completely different flows. The small power-law index leads to a much larger velocity than other cases, while the large power-law index makes the outlet velocity unstable at the middle position.

scholarly journals Evaluating Well-Formedness Constraints on Incomplete Models

2017 ◽  
Vol 23 (2) ◽  
pp. 687-713 ◽  
Author(s):  
Oszkár Semeráth ◽  
Dániel Varró
Keyword(s):  
Pattern Matching ◽  
Modeling Tools ◽  
Graph Pattern Matching ◽  
Model Driven ◽  
Graph Query ◽  
Graph Pattern ◽  
Partial Models ◽  
Graph Queries ◽  
Validation Technique ◽  
Incomplete Models

In modern modeling tools used for model-driven development, the validation of several well-formedness constraints is continuously been carried out by exploiting advanced graph query engines to highlight conceptual design aws. However, while models are still under development, they are frequently par- tial and incomplete. Validating constraints on incomplete, partial models may identify a large number of irrelevant problems. By switching o the val- idation of these constraints, one may fail to reveal problematic cases which are dicult to correct when the model becomes suciently detailed. Here, we propose a novel validation technique for evaluating well-formed- ness constraints on incomplete, partial models with may and must semantics, e.g. a constraint without a valid match is satisable if there is a completion of the partial model that may satisfy it. To this end, we map the problem of constraint evaluation over partial models into regular graph pattern matching over complete models by semantically equivalent rewrites of graph queries.

Power-Law and Long-Memory Characteristics of the Atmospheric General Circulation

2009 ◽  
Vol 22 (11) ◽  
pp. 2890-2904 ◽  
Author(s):  
Dmitry I. Vyushin ◽  
Paul J. Kushner
Keyword(s):  
Climate Variability ◽  
Power Law ◽  
Long Memory ◽  
General Circulation ◽  
Fluctuation Analysis ◽  
Temperature Record ◽  
Power Law Model ◽  
Large Power ◽  
Internal Climate Variability ◽  
Power Law Function

Abstract The question of which statistical model best describes internal climate variability on interannual and longer time scales is essential to the ability to predict such variables and detect periodicities and trends in them. For over 30 yr the dominant model for background climate variability has been the autoregressive model of the first order (AR1). However, recent research has shown that some aspects of climate variability are best described by a “long memory” or “power-law” model. Such a model fits a temporal spectrum to a single power-law function, which thereby accumulates more power at lower frequencies than an AR1 fit. In this study, several power-law model estimators are applied to global temperature data from reanalysis products. The methods employed (the detrended fluctuation analysis, Geweke–Porter-Hudak estimator, Gaussian semiparametric estimator, and multitapered versions of the last two) agree well for pure power-law stochastic processes. However, for the observed temperature record, the power-law fits are sensitive to the choice of frequency range and the intrinsic filtering properties of the methods. The observational results converge once frequency ranges are made consistent and the lowest frequencies are included, and once several climate signals have been filtered. Two robust results emerge from the analysis: first, that the tropical circulation features relatively large power-law exponents that connect to the zonal-mean extratropical circulation; and second, that the subtropical lower stratosphere exhibits power-law behavior that is volcanically forced.

scholarly journals The Unspoken Shaken Baby Lie Detector Algorithm—An Analysis of Diagnostic Procedures in Cases of Allegedly Abusive Head Trauma without External Signs of Trauma

2020 ◽  
Vol 3 (2) ◽  
pp. p52
Author(s):  
Niels Lynøe ◽  
Anders Eriksson
Keyword(s):  
Head Trauma ◽  
Diagnostic Procedures ◽  
Abusive Head Trauma ◽  
Second Step ◽  
Diagnostic Process ◽  
Retinal Hemorrhages ◽  
Explicit Algorithm ◽  
External Sign ◽  
Step Algorithm

Various algorithms have been developed for diagnosis of Abusive Head Trauma (AHT); however, there is no explicit algorithm for the 1/3 of alleged AHT cases which present with findings restricted to subdural and retinal hemorrhages, with or without encephalopathy—i.e., isolated triad cases. Moreover, such cases have been lumped together with AHT cases with external sign of trauma and all diagnosed as AHT despite those we are focusing on lack signs of trauma. It is therefore relevant to analyze how this diagnosis can be reached in the absence of unequivocal trauma. Our analysis indicates that with respect to isolated triad cases, a two-step algorithm seems to be in use—but unspoken. The first step concerns a ruling out diagnostic process and the second step addresses the veracity of the caregivers’ narrative. Both steps are based on the traditional AHT mechanism theories and ten tacitly applied auxiliary hypotheses which are, however, questionable or incorrect. If the traditional AHT mechanism theories and necessary auxiliary hypotheses are not valid, then neither is the two-step algorithm. Accordingly, we propose that in alleged AHT cases with no external signs of trauma, the two-step algorithm—here referred to as the unspoken shaken baby lie detector algorithm—should be abandoned.

Fourier reconstruction of nonuniformly sampled, aliased seismic data

Geophysics ◽  
2007 ◽  
Vol 72 (1) ◽  
pp. V21-V32 ◽  
Author(s):  
P. M. Zwartjes ◽  
M. D. Sacchi
Keyword(s):  
Seismic Data ◽  
Fourier Coefficients ◽  
A Priori ◽  
Nonuniform Sampling ◽  
Second Step ◽  
Fourier Domain ◽  
Sampled Data ◽  
Underlying Assumption ◽  
Fourier Reconstruction ◽  
Step Algorithm

There are numerous methods for interpolating uniformly sampled, aliased seismic data, but few can handle the combination of nonuniform sampling and aliasing. We combine the principles of Fourier reconstruction of nonaliased, nonuniformly sampled data with the ideas of frequency-wavenumber [Formula: see text] interpolation of aliased, uniformly sampled data in a new two-step algorithm. In the first step, we estimate the Fourier coefficients at the lower nonaliased temporal frequencies from the nonuniformly sampled data. The coefficients are then used in the second step as an a priori model to distinguish between aliased and nonaliased energy at the higher, aliased temporal frequencies. By using a nonquadratic model penalty in the inversion, both the artifacts in the Fourier domain from nonuniform sampling and the aliased energy are suppressed. The underlying assumption is that events are planar; therefore, the algorithm is applied to seismic data in overlapping spatiotemporal windows.

GRAPH-BASED ORDERING SCHEME FOR COLOR IMAGE FILTERING

2008 ◽  
Vol 08 (03) ◽  
pp. 473-493 ◽  
Author(s):  
O. LEZORAY ◽  
C. MEURIE ◽  
A. ELMOATAZ
Keyword(s):  
Complete Graph ◽  
Spanning Tree ◽  
Minimum Spanning Tree ◽  
Extreme Values ◽  
Color Image ◽  
Hamiltonian Path ◽  
Image Filtering ◽  
Second Step ◽  
Median Filtering ◽  
Step Algorithm

This paper presents a graph-based ordering scheme of color vectors. A complete graph is defined over a filter window and its structure is analyzed to construct an ordering of color vectors. This graph-based ordering is constructed by finding a Hamiltonian path across the color vectors of a filter window by a two-step algorithm. The first step extracts, by decimating a minimum spanning tree, the extreme values of the color set. These extreme values are considered as the infimum and the supremum of the set of color vectors. The second step builds an ordering by constructing a Hamiltonian path among the vectors of color vectors, starting from the infimum and ending at the supremum. The properties of the proposed graph-based ordering of vectors are detailed. Several experiments are conducted to assess its filtering abilities for morphological and median filtering.

scholarly journals Distributed graph queries over [email protected] for runtime monitoring of cyber-physical systems

2019 ◽  
Vol 22 (1) ◽  
pp. 79-102 ◽  
Author(s):  
Márton Búr ◽  
Gábor Szilágyi ◽  
András Vörös ◽  
Dániel Varró
Keyword(s):  
Real Time ◽  
Cyber Physical Systems ◽  
Model Management ◽  
Runtime Monitoring ◽  
Query Evaluation ◽  
Resource Constrained ◽  
Physical Systems ◽  
Graph Query ◽  
Attributed Graphs ◽  
Graph Queries

Abstract Smart cyber-physical systems (CPSs) have complex interaction with their environment which is rarely known in advance, and they heavily depend on intelligent data processing carried out over a heterogeneous and distributed computation platform with resource-constrained devices to monitor, manage and control autonomous behavior. First, we propose a distributed runtime model to capture the operational state and the context information of a smart CPS using directed, typed and attributed graphs as high-level knowledge representation. The runtime model is distributed among the participating nodes, and it is consistently kept up to date in a continuously evolving environment by a time-triggered model management protocol. Our runtime models offer a (domain-specific) model query and manipulation interface over the reliable communication middleware of the Data Distribution Service (DDS) standard widely used in the CPS domain. Then, we propose to carry out distributed runtime monitoring by capturing critical properties of interest in the form of graph queries, and design a distributed graph query evaluation algorithm for evaluating such graph queries over the distributed runtime model. As the key innovation, our (1) distributed runtime model extends existing publish–subscribe middleware (like DDS) used in real-time CPS applications by enabling the dynamic creation and deletion of graph nodes (without compile time limits). Moreover, (2) our distributed query evaluation extends existing graph query techniques by enabling query evaluation in a real-time, resource-constrained environment while still providing scalable performance. Our approach is illustrated, and an initial scalability evaluation is carried out on the MoDeS3 CPS demonstrator and the open Train Benchmark for graph queries.

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