scholarly journals Evaluation of an optimized bush fire propagation model with large-scale fire experiments

2021 ◽  
Vol 349 (1) ◽  
pp. 43-53
Author(s):  
A. David V. Brou ◽  
Aya Brigitte N’Dri
Keyword(s):  
Large Scale ◽  
Propagation Model ◽  
Fire Propagation ◽  
Bush Fire ◽  
Fire Experiments

scholarly journals The Large Scale Machine Learning in an Artificial Society: Prediction of the Ebola Outbreak in Beijing

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Peng Zhang ◽  
Bin Chen ◽  
Liang Ma ◽  
Zhen Li ◽  
Zhichao Song ◽  
...  
Keyword(s):  
Machine Learning ◽  
Large Scale ◽  
Ebola Virus ◽  
Virus Disease ◽  
Propagation Model ◽  
Propagation Mechanism ◽  
Chinese Government ◽  
Emergency Plans ◽  
Artificial Society ◽  
The City

Ebola virus disease (EVD) distinguishes its feature as high infectivity and mortality. Thus, it is urgent for governments to draw up emergency plans against Ebola. However, it is hard to predict the possible epidemic situations in practice. Luckily, in recent years, computational experiments based on artificial society appeared, providing a new approach to study the propagation of EVD and analyze the corresponding interventions. Therefore, the rationality of artificial society is the key to the accuracy and reliability of experiment results. Individuals’ behaviors along with travel mode directly affect the propagation among individuals. Firstly, artificial Beijing is reconstructed based on geodemographics and machine learning is involved to optimize individuals’ behaviors. Meanwhile, Ebola course model and propagation model are built, according to the parameters in West Africa. Subsequently, propagation mechanism of EVD is analyzed, epidemic scenario is predicted, and corresponding interventions are presented. Finally, by simulating the emergency responses of Chinese government, the conclusion is finally drawn that Ebola is impossible to outbreak in large scale in the city of Beijing.

Phenomenon Identification and Ranking Exercise and a Review of Large-Scale Spray Modeling Technology

2008 ◽  
Author(s):  
Alexander L. Brown ◽  
Sam S. Yoon ◽  
Richard A. Jepsen
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Fire Suppression ◽  
Particle Surface ◽  
Liquid Fuels ◽  
Fire Propagation ◽  
Research Activities ◽  
Ranking Exercise ◽  
Productive Research ◽  
Multi Phase

We are engaged in efforts to model spray phenomena. Applications of principal interest include the high-speed impact of large vessels of fuel and the subsequent fire, fire suppression, solid propellant fires, pressurized pipe or tank rupture, and fire propagation for cascading liquid fuels. To help guide research and development efforts geared towards designing an appropriate spray modeling capability, a Phenomenon Identification and Ranking exercise was conducted. The summarized results of the exercise in tabular format, a Phenomenon Identification and Ranking Table (PIRT), are presented. The table forms the context for a textual literature review of the existing state of knowledge for modeling applications of interest. This exercise highlights some of the shortcomings in existing tools and knowledge, and suggests productive research activities that can help advance the modeling capabilities for the desired applications. Notable needs exist for research in high Weber number particle-surface impacts, particle collisions, multi-physics couplings, and low void fraction multi-phase coupling.

scholarly journals Propagation Model in Indoor and Outdoor for the LTE Communications

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
Sun-Kuk Noh ◽  
DongYou Choi
Keyword(s):  
Mobile Communication ◽  
Mobile Communications ◽  
Communication Systems ◽  
Large Scale ◽  
Propagation Model ◽  
Time Rate ◽  
Propagation Models ◽  
5G Mobile Communication ◽  
Time Changes ◽  
Indoor And Outdoor

Rapidly rising demand for radio communication and the explosion in the number of mobile communications service subscribers have led to the need for optimization in the development of fifth-generation (5G) mobile communication systems. Previous studies on the development of propagation models considering a propagation environment in the existing microwave band have been mainly focused on analyzing the propagation characteristics with regard to large-scale factors such as path losses, delay propagation, and angle diffusions. In this paper, we investigated the concept of spatial and time changes ratios in the measurement of wave propagations and measured RSRP of Long Term Evolution (LTE) signals at three locations considering the time rate of 1% and 50%. We confirmed the concept of spatial and time changes rate based on the results of analyzing the signal data measured and proposed the propagation models 1 and 2 in microcell downtown. The forecast results using proposed models 1 and 2 were better than the COST231 model in both indoor and outdoor measured places. It was predicted between a time rate of 1% and 50% indoor within 400m and outdoor within 200m. In the future, we will study the propagation model of 5G mobile communication as well as the current 4G communication using artificial intelligence technology.

Polycyclic Aromatic Hydrocarbons (PAHs) Quantified in Large-Scale Fire Experiments

2011 ◽  
Vol 48 (2) ◽  
pp. 513-528 ◽  
Author(s):  
Per Blomqvist ◽  
Margaret Simonson McNamee ◽  
Petra Andersson ◽  
Anders Lönnermark
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Large Scale ◽  
Polycyclic Aromatic ◽  
Fire Experiments

scholarly journals Parameter Estimation for the Forest Fire Propagation Model

2020 ◽  
Vol 75 (1) ◽  
pp. 1-22
Author(s):  
Martin Ambroz ◽  
Karol Mikula ◽  
Marek Fraštia ◽  
Marián Marčiš
Keyword(s):  
Data Assimilation ◽  
Forest Fire ◽  
Hausdorff Distance ◽  
Small Time ◽  
Propagation Model ◽  
Model Parameters ◽  
Normal Velocity ◽  
Fire Propagation ◽  
Rate Of Spread ◽  
Fire Front

AbstractThis paper first gives a brief overview of the Lagrangian forest fire propagation model [Ambroz, M.—Balažovjech, M.—Medl’a, M.—Mikula, K.: Numerical modeling of wildland surface fire propagation by evolving surface curves, Adv. Comput. Math. 45 (2019), no. 2, 1067–1103], which we apply to grass-field areas. Then, we aim to estimate the optimal model parameters. To achieve this goal, we use data assimilation of the measured data. From the data, we are able to estimate the normal velocity of the fire front (rate of spread), dominant wind direction and selected model parameters. In the data assimilation process, we use the Hausdorff distance as well as the Mean Hausdorff distance as a criterion. Moreover, we predict the fire propagation in small time intervals.

scholarly journals Modelling the Impact of Climate Change on Coastal Flooding: Implications for Coastal Structures Design

2021 ◽  
Vol 9 (9) ◽  
pp. 1008 ◽  
Author(s):  
Achilleas Samaras ◽  
Theophanis Karambas
Keyword(s):  
Climate Change ◽  
Wave Propagation ◽  
Large Scale ◽  
Coastal Flooding ◽  
Propagation Model ◽  
Coastal Protection ◽  
Impact Of Climate Change ◽  
The Impact ◽  
Wave Propagation Model ◽  
Modelling Approach

In the present work, the impact of climate change on coastal flooding is investigated through a set of interoperable models developed by the authors, following a modular modelling approach and adapting the modelling sequence to two separate objectives with respect to inundation over large-scale areas and coastal protection structures’ design. The modelling toolbox used includes a large-scale wave propagation model, a storm-induced circulation model, and an advanced nearshore wave propagation model based on the higher order Boussinesq-type equations, all of which are presented in detail. Model capabilities are validated and applications are made for projected scenarios of climate change-induced wave and storm surge events, simulating coastal flooding over the low-lying areas of a semi-enclosed bay and testing the effects of different structures on a typical sandy beach (both in northern Greece). This work is among the few in relevant literature that incorporate a fully non-linear wave model to a modelling system aimed at representing coastal flooding. Results highlight the capabilities of the presented modelling approach and set the basis for a comprehensive evaluation of the use of advanced modelling tools for the design of coastal protection and adaptation measures against future climatic pressures.

Flatland in flames: a two-dimensional crown fire propagation model

2009 ◽  
Vol 18 (5) ◽  
pp. 527 ◽  
Author(s):  
James D. Dickinson ◽  
Andrew P. Robinson ◽  
Paul E. Gessler ◽  
Richy J. Harrod ◽  
Alistair M. S. Smith
Keyword(s):  
Bulk Density ◽  
Original Data ◽  
Propagation Model ◽  
Crown Fire ◽  
Wagner Model ◽  
Fire Propagation ◽  
Rate Of Spread ◽  
Proposed Model ◽  
Foliar Biomass ◽  
Canopy Bulk Density

The canopy bulk density metric is used to describe the fuel available for combustion in crown fire models. We propose modifying the Van Wagner crown fire propagation model, used to estimate the critical rate of spread necessary to sustain active crown fire, to use foliar biomass per square metre instead of canopy bulk density as the fuel input. We tested the efficacy of our proposed model by comparing predictions of crown fire propagation with Van Wagner’s original data. Our proposed model correctly predicted each instance of crown fire presented in the seminal study. We then tested the proposed model for statistical equivalence to the original Van Wagner model using two contemporary techniques to parameterize canopy bulk density. We found the proposed and original models to be statistically equivalent when canopy bulk density was parameterized using the method incorporated in the Fire and Fuels Extension to the Forest Vegetation Simulator (difference < 0.5 km h–1, α = 0.05, n = 2626), but not when parameterized using the method of Cruz and others. Use of foliar biomass per unit area in the proposed model makes for more accurate and easily obtained fuel estimates without sacrificing the utility of the Van Wagner model.

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