4,254 research outputs found
ns-3 Airborne Network Simulation
Airborne networks, consisting of aircraft-to-aircraft and aircraft-to-ground communications, are critical for future aviation information systems and remote Internet access. A major knowledge gap, however, is the reliability and security challenges of airborne networks in such civilian application domains. Field tests and emulations of airborne networks are expensive undertakings and would be better informed by simulation findings. This paper, hence, reports about a study that aims to simulate airborne networks to understand and characterize their performance and risks. We choose ns-3, an open source network simulation tool, to construct and evaluate airborne networks. We implement 3-D mobility models in ns-3 to capture the realistic movement of aircraft and assess the performance of elemental airborne network configurations in terms of metrics such as throughput and packet drop ratio. We conclude with lessons learnt and some future research directions
Opportunistic Networks: Present Scenario- A Mirror Review
Opportunistic Network is form of Delay Tolerant Network (DTN) and regarded as extension to Mobile Ad Hoc Network. OPPNETS are designed to operate especially in those environments which are surrounded by various issues like- High Error Rate, Intermittent Connectivity, High Delay and no defined route between source to destination node. OPPNETS works on the principle of “Store-and-Forward” mechanism as intermediate nodes perform the task of routing from node to node. The intermediate nodes store the messages in their memory until the suitable node is not located in communication range to transfer the message to the destination. OPPNETs suffer from various issues like High Delay, Energy Efficiency of Nodes, Security, High Error Rate and High Latency. The aim of this research paper is to overview various routing protocols available till date for OPPNETs and classify the protocols in terms of their performance. The paper also gives quick review of various Mobility Models and Simulation tools available for OPPNETs simulation
Benchmarking Wireless Network Protocols: Threat and Challenge Analysis of the AeroRP
To accommodate the unique conditions of mobile wireless networks, numerous protocols have been designed. Protocols are initially tested through simulation software, but often under non-realistic conditions, using simple or even ideal wireless environments not usually found in the real world. Without challenges and channel impairments, such simulations cannot accurately determine the advantages and disadvantages of the protocol nor can a reliable comparison be made between the performance of any two protocols. New protocols must be tested in a manner consistent with legacy protocols so they can be accurately compared and improved upon. The contributions of this thesis are a set of models that can create more realistic and challenging simulations, including a 3-D implementation of the Gauss-Markov mobility model, and a set of benchmarks that can be used to test the strengths and weaknesses of wireless routing protocols. These benchmarks are then applied to several MANET protocols including AODV, DSR, OLSR, DSDV, and AeroRP that is part of the Aero protocol stack developed at The University of Kansas. AeroRP outperforms the traditional MANET routing protocols in benchmarks that involve either highly-dynamic networks or disruptions in connectivity
Lightweight Simulation of Hybrid Aerial- and Ground-based Vehicular Communication Networks
Cooperating small-scale Unmanned Aerial Vehicles (UAVs) will open up new
application fields within next-generation Intelligent Transportation Sytems
(ITSs), e.g., airborne near field delivery. In order to allow the exploitation
of the potentials of hybrid vehicular scenarios, reliable and efficient
bidirectional communication has to be guaranteed in highly dynamic
environments. For addressing these novel challenges, we present a lightweight
framework for integrated simulation of aerial and ground-based vehicular
networks. Mobility and communication are natively brought together using a
shared codebase coupling approach, which catalyzes the development of novel
context-aware optimization methods that exploit interdependencies between both
domains. In a proof-of-concept evaluation, we analyze the exploitation of UAVs
as local aerial sensors as well as aerial base stations. In addition, we
compare the performance of Long Term Evolution (LTE) and Cellular
Vehicle-to-Everything (C-V2X) for connecting the ground- and air-based
vehicles
High Resolution Spatio-Temporal Model for Room-Level Airborne Pandemic Spread
Airborne pandemics have caused millions of deaths worldwide, large-scale
economic losses, and catastrophic sociological shifts in human history.
Researchers have developed multiple mathematical models and computational
frameworks to investigate and predict the pandemic spread on various levels and
scales such as countries, cities, large social events, and even buildings.
However, modeling attempts of airborne pandemic dynamics on the smallest scale,
a single room, have been mostly neglected. As time indoors increases due to
global urbanization processes, more infections occur in shared rooms. In this
study, a high-resolution spatio-temporal epidemiological model with airflow
dynamics to evaluate airborne pandemic spread is proposed. The model is
implemented using high-resolution 3D data obtained using a light detection and
ranging (LiDAR) device and computing the model based on the Computational Fluid
Dynamics (CFD) model for the airflow and the Susceptible-Exposed-Infected (SEI)
model for the epidemiological dynamics. The pandemic spread is evaluated in
four types of rooms, showing significant differences even for a short exposure
duration. We show that the room's topology and individual distribution in the
room define the ability of air ventilation to reduce pandemic spread throughout
breathing zone infection
A survey on network simulators in three-dimensional wireless ad hoc and sensor networks
© 2016 The Author(s). As steady research in wireless ad hoc and sensor networks is going on, performance evaluation through relevant network simulator becomes indispensable procedure to demonstrate superiority to comparative schemes and suitability in most literatures. Thus, it is very important to establish credibility of simulation results by investigating merits and limitations of each simulator prior to selection. Based on this motivation, in this article, we present a comprehensive survey on current network simulators for new emerging research area, three-dimensional wireless ad hoc and sensor networks which is represented by airborne ad hoc networks and underwater sensor networks by reviewing major existing simulators as well as presenting their main features in several aspects. In addition, we address the outstanding mobility models which are main components in simulation study for self-organizing ad hoc networks. Finally, open research issues and research challenges are discussed and presented
Novel approach to observing system simulation experiments improves information gain of surface-atmosphere field measurements
The observing system design of multidisciplinary field measurements involves a variety of considerations on logistics, safety, and science objectives. Typically, this is done based on investigator intuition and designs of prior field measurements. However, there is potential for considerable increases in efficiency, safety, and scientific success by integrating numerical simulations in the design process. Here, we present a novel numerical simulation-environmental response function (NS-ERF) approach to observing system simulation experiments that aids surface-atmosphere synthesis at the interface of mesoscale and microscale meteorology. In a case study we demonstrate application of the NS-ERF approach to optimize the Chequamegon Heterogeneous Ecosystem Energy-balance Study Enabled by a High-density Extensive Array of Detectors 2019 (CHEESEHEAD19). During CHEESEHEAD19 pre-field simulation experiments, we considered the placement of 20 eddy covariance flux towers, operations for 72h of low-altitude flux aircraft measurements, and integration of various remote sensing data products. A 2h high-resolution large eddy simulation created a cloud-free virtual atmosphere for surface and meteorological conditions characteristic of the field campaign domain and period. To explore two specific design hypotheses we super-sampled this virtual atmosphere as observed by 13 different yet simultaneous observing system designs consisting of virtual ground, airborne, and satellite observations. We then analyzed these virtual observations through ERFs to yield an optimal aircraft flight strategy for augmenting a stratified random flux tower network in combination with satellite retrievals. We demonstrate how the novel NS-ERF approach doubled CHEESEHEAD19's potential to explore energy balance closure and spatial patterning science objectives while substantially simplifying logistics. Owing to its modular extensibility, NS-ERF lends itself to optimizing observing system designs also for natural climate solutions, emission inventory validation, urban air quality, industry leak detection, and multi-species applications, among other use cases. © 2021 Stefan Metzger et al
Novel approach to observing system simulation experiments improves information gain of surface-atmosphere field measurements
The observing system design of multidisciplinary field
measurements involves a variety of considerations on logistics, safety, and
science objectives. Typically, this is done based on investigator intuition
and designs of prior field measurements. However, there is potential for
considerable increases in efficiency, safety, and scientific success by
integrating numerical simulations in the design process. Here, we present a
novel numerical simulation–environmental response function (NS–ERF)
approach to observing system simulation experiments that aids
surface–atmosphere synthesis at the interface of mesoscale and microscale
meteorology. In a case study we demonstrate application of the NS–ERF
approach to optimize the Chequamegon Heterogeneous Ecosystem Energy-balance
Study Enabled by a High-density Extensive Array of Detectors 2019
(CHEESEHEAD19).
During CHEESEHEAD19 pre-field simulation experiments, we considered the
placement of 20 eddy covariance flux towers, operations for 72 h of
low-altitude flux aircraft measurements, and integration of various remote
sensing data products. A 2 h high-resolution large eddy simulation
created a cloud-free virtual atmosphere for surface and meteorological
conditions characteristic of the field campaign domain and period. To
explore two specific design hypotheses we super-sampled this virtual
atmosphere as observed by 13 different yet simultaneous observing system
designs consisting of virtual ground, airborne, and satellite observations.
We then analyzed these virtual observations through ERFs to yield an optimal
aircraft flight strategy for augmenting a stratified random flux tower
network in combination with satellite retrievals.
We demonstrate how the novel NS–ERF approach doubled CHEESEHEAD19's
potential to explore energy balance closure and spatial patterning science
objectives while substantially simplifying logistics. Owing to its modular
extensibility, NS–ERF lends itself to optimizing observing system designs also
for natural climate solutions, emission inventory validation, urban air
quality, industry leak detection, and multi-species applications, among other
use cases.</p
- …