Point Patterns on a Linear Network

2015 ◽  
pp. 727-762
Keyword(s):  
Linear Network ◽  
Point Patterns

INTEGRAL ASSESSMENT OF ANTHROPOGENIC PRESSURE ON WATER BODIES IN THE LAKE BAIKAL BASIN

2020 ◽  
Author(s):  
Irina Ulzetueva ◽  
Bair Gomboev ◽  
Daba Zhamyanov ◽  
Valentin Batomunkuev ◽  
Zorikto Banzaraktsaev
Keyword(s):  
Lake Baikal ◽  
River Basins ◽  
Anthropogenic Load ◽  
Anthropogenic Pressure ◽  
Linear Network ◽  
Baikal Basin ◽  
Discharge Water ◽  
Lake Baikal Basin ◽  
Integral Assessment ◽  
The Impact

The integrated assessment of the ecological state of the main rivers of the lake Baikal basin - Verkhnyaya Angara, Tyya, Barguzin, Selenga, Snezhnaya, Bolshaya Rechka, Khilok, Chikoy is based on the assessment of the variability of the basin system under the influence of two groups of indicators: 1) Direct (immediate) impact - the volume of water intake and wastewater discharge, water use and sequential water supply. Assessment of the impact on the state of the above-listed rivers basins from wastewater was performed using the algorithm proposed by A. Korolev et al. (2007). 2) Indirect (mediate) impact - indicators of areal and linear-network impacts on the catchment area. Based on the calculation of the integral anthropogenic pressure on the territory of the above-listed river basins, only the Selenga river experiences an “average” anthropogenic load. On the territory of most river basins, the anthropogenic load is “lowered” and “low”.

scholarly journals Does fluvial channel-belt clustering predict net sand to gross rock volume? Architectural metrics and point-pattern analysis of a digital outcrop model

2019 ◽  
Vol 89 (11) ◽  
pp. 1109-1126
Author(s):  
Alexander R. Koch ◽  
Cari L. Johnson ◽  
Lisa Stright
Keyword(s):  
Large Scale ◽  
Small Scale ◽  
Point Pattern ◽  
Point Patterns ◽  
Spatial Point ◽  
Channel Belt ◽  
John Henry Member ◽  
Scale Point ◽  
Belt Width ◽  
Digital Outcrop

ABSTRACT Spatial point-pattern analyses (PPAs) are used to quantify clustering, randomness, and uniformity of the distribution of channel belts in fluvial strata. Point patterns may reflect end-member fluvial architecture, e.g., uniform compensational stacking and avulsion-generated clustering, which may change laterally, especially at greater scales. To investigate spatial and temporal changes in fluvial systems, we performed PPA and architectural analyses on extensive outcrops of the Cretaceous John Henry Member of the Straight Cliffs Formation in southern Utah, USA. Digital outcrop models (DOMs) produced using unmanned aircraft system-based stereophotogrammetry form the basis of detailed interpretations of a 250-m-thick fluvial succession over a total outcrop length of 4.5 km. The outcrops are oriented roughly perpendicular to fluvial transport direction. This transverse cross-sectional exposure of the fluvial system allows a study of the system's variation along depositional strike. We developed a workflow that examines spatial point patterns using the quadrat method, and architectural metrics such as net sand to gross rock volume (NTG), amalgamation index, and channel-belt width and thickness within moving windows. Quadrat cell sizes that are ∼ 50% of the average channel-belt width-to-thickness ratio (16:1 aspect ratio) provide an optimized scale to investigate laterally elongate distributions of fluvial-channel-belt centroids. Large-scale quadrat point patterns were recognized using an array of four quadrat cells, each with 237× greater area than the median channel belt. Large-scale point patterns and NTG correlate negatively, which is a result of using centroid-based PPA on a dataset with disparately sized channel belts. Small-scale quadrat point patterns were recognized using an array of 16 quadrat cells, each with 21× greater area than the median channel belt. Small-scale point patterns and NTG correlate positively, and match previously observed stratigraphic trends in the fluvial John Henry Member, suggesting that these are regional trends. There are deviations from these trends in architectural statistics over small distances (hundreds of meters) which are interpreted to reflect autogenic avulsion processes. Small-scale autogenic processes result in architecture that is difficult to correlate between 1D datasets, for example when characterizing a reservoir using well logs. We show that 1D NTG provides the most accurate prediction for surrounding 2D architecture.

A note on the detection of linear point patterns

1991 ◽  
Vol 55 (1-2) ◽  
pp. 151-152
Author(s):  
Zhang Dayong
Keyword(s):  
Point Patterns

scholarly journals A Secure Protocol against Selfish and Pollution Attacker Misbehavior in Clustered WSNs

Electronics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1244
Author(s):  
Hana Rhim ◽  
Damien Sauveron ◽  
Ryma Abassi ◽  
Karim Tamine ◽  
Sihem Guemara
Keyword(s):  
Denial Of Service ◽  
Base Station ◽  
Hierarchical Organization ◽  
Secure Routing ◽  
Sensor Nodes ◽  
Dos Attacks ◽  
Linear Network ◽  
Secure Protocol ◽  
Misbehaving Nodes ◽  
Pollution Attacks

Wireless sensor networks (WSNs) have been widely used for applications in numerous fields. One of the main challenges is the limited energy resources when designing secure routing in such networks. Hierarchical organization of nodes in the network can make efficient use of their resources. In this case, a subset of nodes, the cluster heads (CHs), is entrusted with transmitting messages from cluster nodes to the base station (BS). However, the existence of selfish or pollution attacker nodes in the network causes data transmission failure and damages the network availability and integrity. Mainly, when critical nodes like CH nodes misbehave by refusing to forward data to the BS, by modifying data in transit or by injecting polluted data, the whole network becomes defective. This paper presents a secure protocol against selfish and pollution attacker misbehavior in clustered WSNs, known as (SSP). It aims to thwart both selfish and pollution attacker misbehaviors, the former being a form of a Denial of Service (DoS) attack. In addition, it maintains a level of confidentiality against eavesdroppers. Based on a random linear network coding (NC) technique, the protocol uses pre-loaded matrices within sensor nodes to conceive a larger number of new packets from a set of initial data packets, thus creating data redundancy. Then, it transmits them through separate paths to the BS. Furthermore, it detects misbehaving nodes among CHs and executes a punishment mechanism using a control counter. The security analysis and simulation results demonstrate that the proposed solution is not only capable of preventing and detecting DoS attacks as well as pollution attacks, but can also maintain scalable and stable routing for large networks. The protocol means 100% of messages are successfully recovered and received at the BS when the percentage of lost packets is around 20%. Moreover, when the number of misbehaving nodes executing pollution attacks reaches a certain threshold, SSP scores a reception rate of correctly reconstructed messages equal to 100%. If the SSP protocol is not applied, the rate of reception of correctly reconstructed messages is reduced by 90% at the same case.

scholarly journals Testing the first-order separability hypothesis for spatio-temporal point patterns

2021 ◽  
pp. 107245
Author(s):  
Mohammad Ghorbani ◽  
Nafiseh Vafaei ◽  
Jiří Dvořák ◽  
Mari Myllymäki
Keyword(s):  
First Order ◽  
Point Patterns ◽  
Spatio Temporal

scholarly journals Filtering spatial point patterns using kernel densities

2021 ◽  
Vol 41 ◽  
pp. 100487
Author(s):  
Brian E. Vestal ◽  
Nichole E. Carlson ◽  
Debashis Ghosh
Keyword(s):  
Point Patterns ◽  
Spatial Point ◽  
Spatial Point Patterns
Sign in / Sign up

Export Citation Format

Share Document