scholarly journals Analysis of Major Rainfall Factors Affecting Inundation Based on Observed Rainfall and Random Forest

2020 ◽  
Vol 20 (6) ◽  
pp. 301-310
Author(s):  
Hyunil Kim ◽  
Byunghyun Kim
Keyword(s):  
Random Forest ◽  
Numerical Models ◽  
Statistical Characteristics ◽  
Target Area ◽  
Two Dimensional ◽  
Weather System ◽  
Urban Flood ◽  
Maximum Rainfall ◽  
Factors Affecting ◽  
The Impact

It is important to analyze urban floods according to uncertain rainfall patterns. This study was carried out to determine key statistical characteristics of rainfall affecting the occurrences of flooding by using observed rainfall, one- and two-dimensional hydraulic analysis models, and random forests. The target area selected was the Centum City area of Busan, where flooding occurs frequently with heavy rainfall. For analysis, the rainfall data from the Automatic Weather System (AWS) and radar observatory in the entire city of Busan were collected. Using the results from the one- and two-dimensional numerical models, the occurrence of flooding was determined according to the observed rainfall events. The random forest was used to classify the presence or absence of flooding according to the statistical characteristics of rainfall, and the importance evaluation function was applied to determine the impact of each statistical factor. The three main statistical factors of rainfall with the greatest impact on the occurrence of flooding were analyzed as the 1-hr maximum rainfall, the average rainfall, and the skewness. On the other hand, the three main factors affecting the maximum flood depth were the 3-hrs maximum rainfall, the 1-hr maximum rainfall, and the total rainfall. It is judged that the results of this study will be useful in suggesting quantitative urban flood forecasting standards when rainfall is examined in real-time by using various observation equipment.

Comparison of numerical advection schemes in two-dimensional turbulence simulation

2017 ◽  
Vol 32 (1) ◽  
Author(s):  
Pavel A. Perezhogin ◽  
Andrey V. Glazunov ◽  
Evgeny V. Mortikov ◽  
Valentin P. Dymnikov
Keyword(s):  
Spatial Resolution ◽  
Climate Model ◽  
Numerical Models ◽  
Weather Forecast ◽  
Statistical Characteristics ◽  
Small Scale ◽  
External Forcing ◽  
Two Dimensional ◽  
Medium Range Weather Forecast ◽  
Advection Schemes

AbstractThe influence of numerical approximations on statistical characteristics of modelled two-dimensional turbulence sustained by a stochastic external forcing is studied. The ability of various finite-difference and semi-Lagrangian schemes to reproduce reliably the dual energy and enstrophy cascades for coarse spatial resolution is tested. It is also studied how the requirement of preserving invariants inherent to a two-dimensional ideal fluid is important relative to numerical schemes. The results of calculations with high spatial resolution were taken as a reference solution. The choice of studied schemes was motivated by their use in atmosphere and ocean numerical models, in particular, in the Institute of Numerical Mathematics climate model (INMCM) and semi-Lagrangian absolute vorticity (SLAV) model of medium-range weather forecast. The importance of conservation laws for integral vorticity and enstrophy is revealed in the numerical experiments with a small-scale external forcing.

scholarly journals Comparative Analysis of Building Representations in TELEMAC-2D for Flood Inundation in Idealized Urban Districts

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1840 ◽  
Author(s):  
Li ◽  
Liu ◽  
Mei ◽  
Shao ◽  
Wang ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Numerical Models ◽  
Flood Inundation ◽  
Complex Flow ◽  
Urban Flood ◽  
Urban Districts ◽  
Mesh Resolution ◽  
Flood Simulations ◽  
The Impact ◽  
Better Than

This study aims to better understand the impact of different building representations and mesh resolutions on urban flood simulations using the TELEMAC-2D model in idealized urban districts. A series of numerical models based on previous laboratory experiments was established to simulate urban flooding around buildings, wherein different building layouts (aligned and staggered) were modeled for different building representations: building–hole (BH), building–block (BB), and building–resistance (BR) methods. A sensitivity analysis of the Manning coefficient for building grids indicated that the unit-width discharge and water depth in building grids reduce as the Manning coefficient is less than 104 m-1/3⋅s. The simulated depths via the BH, BB, and BR methods were compared with the measured data in terms of three accuracy indicators: root mean square error, Pearson product–moment correlation coefficient, and Nash–Sutcliffe efficiency. Observing apparent discrepancies based on the hydrographs was difficult; however, some slight distinctions were observed based on the aforementioned three indicators. The sensitivity of 1, 2, and 5 cm mesh resolutions was also analyzed: results obtained using 1 cm resolution were better than those obtained using other resolutions. The complex flow regime around buildings was also investigated based on mesh resolution, velocity, and Froude number according to our results. This study provides key data regarding urban flood model benchmarks, focusing on the effect of different building representations and mesh resolutions.

scholarly journals Influence of Detailed Topography when Modeling Flows in Street Junction During Urban Flood

2012 ◽  
Vol 7 (5) ◽  
pp. 560-566 ◽  
Author(s):  
Pierre-Henri Bazin ◽  
◽  
Anne Bessette ◽  
Emmanuel Mignot ◽  
André Paquier ◽  
...  
Keyword(s):  
Urban Areas ◽  
Large Scale ◽  
Numerical Models ◽  
Flow Section ◽  
Urban Flood ◽  
Eddy Viscosity Model ◽  
Image Velocimetry ◽  
Urban Topography ◽  
Scale Particle ◽  
The Impact

Floods in dense urban areas propagatemainly through the streets, where the flow can be locally affected by elements of urban topography. This study aims at assessing the need of integrating detailed topography in numerical models when simulating urban floods. Acoustic Doppler Velocimetry and Large Scale Particle Image Velocimetry measurements in an experimental three branch junction representing a city crossroad are used to calibrate a numerical model solving the 2D shallow water equations. A constant eddy viscosity model proves to be accurate enough to calculate velocity fields, but such model requires a fine calibration against experimental data. Simulations run with this calibrated model are performed to study the impact of obstacles and sidewalks representative of urban areas. It is found that obstacles located in the downstream branch can highly perturb the velocities distribution downstream of the junction, whereas obstacles located in the upstream branches have less influence. The presence of sidewalks results in reduced flow section and higher velocities, but additional effects occur within and downstream of the junction. Simulations presented here show the need of considering detailed topography and elements of urban furniture if local velocities have to be represented.

scholarly journals Impact of TMI SST on the Simulation of a Heavy Rainfall Episode over Mumbai on 26 July 2005

2008 ◽  
Vol 136 (10) ◽  
pp. 3714-3741 ◽  
Author(s):  
S. K. Deb ◽  
C. M. Kishtawal ◽  
P. K. Pal ◽  
P. C. Joshi
Keyword(s):  
Large Scale ◽  
Numerical Models ◽  
Convective Available Potential Energy ◽  
India Meteorological Department ◽  
Tropical Rainfall Measuring Mission ◽  
Atmospheric Modeling ◽  
Cumulus Parameterization ◽  
Surface Boundary ◽  
Maximum Rainfall ◽  
The Impact

In this study the simulation of a severe rainfall episode over Mumbai on 26 July 2005 has been attempted with two different mesoscale models. The numerical models used in this study are the Brazilian Regional Atmospheric Modeling System (BRAMS) developed originally by Colorado State University and the Advanced Research Weather Research Forecast (WRF-ARW) Model, version 2.0.1, developed at the National Center for Atmospheric Research. The simulations carried out in this study use the Grell–Devenyi Ensemble cumulus parameterization scheme. Apart from using climatological sea surface temperature (SST) for the control simulations, the impact of the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) SST on the simulation of rainfall is evaluated using these two models. The performances of the models are compared by examining the predicted parameters like upper- and lower-level circulations, moisture, temperature, and rainfall. The strength of convective instability is also derived by calculating the convective available potential energy. The intensity of maximum rainfall around Mumbai is significantly improved with TMI SST as the surface boundary condition in both the models. The large-scale circulation features, moisture, and temperature are compared with those in the National Centers for Environmental Prediction analyses. The rainfall prediction is assessed quantitatively by comparing the simulated rainfall with the rainfall from TRMM products and the observed station values reported in Indian Daily Weather Reports from the India Meteorological Department.

Large Deformation Numerical Simulations Regarding Soil Plugging Behaviour Inside Open-Ended Piles

2012 ◽  
Author(s):  
Sascha Henke
Keyword(s):  
Numerical Models ◽  
Soil Plug ◽  
Factors Affecting ◽  
Pile Installation ◽  
Pile Diameter ◽  
Key Factor ◽  
Vertical Bearing ◽  
The One ◽  
Plug Formation ◽  
The Impact

Soil-plugging inside open-ended piles is a well-known phenomenon which increases vertical bearing capacity on the one hand but also leads to increasing driving resistance. There are many different factors affecting the tendency of soil-plug formation like pile diameter, geometry of the pile, installation method, soil density and so on. With the basis of experimental data numerical models to simulate the pile installation process to better understand the mechanisms of soil plugging inside open-ended piles are validated. The validated numerical models are used to examine different aspects regarding the phenomenon of soil plug formation. First, the evolution of internal and external shaft friction is investigated in more detail with focus on pile diameter. Furthermore, the impact of internal reinforcements like internal rings are investigated numerically. The shape of the internal ring is varied throughout this study to evaluate the influence of this key factor on internal stress development.

DAMPAK KEBIJAKAN FISKAL TERHADAP KINERJA SEKTOR PERTANIAN DI SULAWESI TENGGARA

2017 ◽  
Vol 1 (1) ◽  
Author(s):  
La Ode Jabuddin ◽  
Ayub M Padangaran ◽  
Azhar Bafadal Bafadal
Keyword(s):  
Fiscal Policy ◽  
Interest Rates ◽  
Agricultural Sector ◽  
Simultaneous Equations ◽  
Poor People ◽  
Land Area ◽  
Factors Affecting ◽  
Historical Simulation ◽  
The Impact ◽  
Direct Expenditure

This study aims to: (1) Knowing the dynamics of fiscal policy and the performance of the agricultural sector, (2) Analyze the factors that influence fiscal policy and the performance                   of the agricultural sector, and (3) Analyzing the impact of fiscal policy on the performance of the agricultural sector. The data used in this study were pooled 2005-2013 data in the aggregate. Econometric model the impact of fiscal policy on the performance of the agricultural sector is built in the form of simultaneous equations, consisting of 7 equations with 25 total variables in the model, 7 endogenous variables, 12 exogenous variables, and 6 variables lag. The model is estimated by 2SLS method SYSLIN procedures and historical simulation with SIMNLIN procedure.The results showed that: (1) The development of fiscal policy in Southeast Sulawesi from year to year tends to increase, (2) The performance of the agricultural sector from the aspect of GDP has decreased, from the aspect of labor is still consistent, in terms of investment to grow positively, and assign roles which means to decrease the number of poor people, (3) factors affecting fiscal policy is local revenues, equalization funds, other revenues, as well as the lag fiscal policy, (4) the factors that affect the performance of the agricultural sector from the aspect GDP is labor, direct expenditure and GDP lag; from the aspect of labor is the total labor force, investment, land area, direct expenditure, as well as the lag of labor; from the aspect of investment is influenced by GDP per capita, land area, interest rates and investment lag; as well as from the aspect of poor people, are affected by population, investments, direct expenditure and poverty lag, (5). Fiscal policy impact on the agricultural sector GDP increase, a decrease in the number of poor, declining agricultural laborers, and a decrease in the amount of investment in the agricultural sector.Keywords: Fiscal policy, the performance of the agricultural sector, the simultaneous equations

Structural Model of Service Quality Factors Affecting Loyalty Sustainability

2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Eman Al-erqi ◽  
◽  
Mohd Lizam Mohd Diah ◽  
Najmaddin Abo Mosali ◽  
◽  
...  
Keyword(s):  
International Students ◽  
Service Quality ◽  
Goodness Of Fit ◽  
Structural Model ◽  
Quality Factors ◽  
Factors Affecting ◽  
Measurement Models ◽  
Confirmatory Factor ◽  
The University ◽  
The Impact

This study seeks to address the impact of service quality affecting international student's satisfaction towards loyalty tothe Universiti Tun Hussein Onn Malaysia(UTHM). The aim of thestudy is to develop relationship between service quality factor and loyalty to the university from the international students’ perspectives. The study adopted quantitative approach where data was collected through questionnaire survey and analysed statistically. A total of 246 responses were received and found to be valid. The model was developed and analysed using AMOS-SEM software. Confirmatory factor analysis (CFA) function of the software was to assessed the measurement models and found that all the models achieved goodness of fit. Then path analysis function was used to assessed structural model and found that service qualityfactors have a significant effect on the students’ satisfaction and thus affecting the loyaltyto the university. Hopefully the outcome form this study will benefit the university in providing services especially to the international students.

The Random Forest Method in Research of Impact of Macroeconomic Indicators of Regional Development on Informal Employment Rate

2020 ◽  
Vol 27 (6) ◽  
pp. 37-55
Author(s):  
E. V. Zarova ◽  
E. I. Dubravskaya
Keyword(s):  
Random Forest ◽  
Regional Development ◽  
Russian Federation ◽  
Regional Level ◽  
Informal Employment ◽  
Macroeconomic Factors ◽  
Random Forest Method ◽  
Macroeconomic Indicators ◽  
The Russian Federation ◽  
The Impact

The topic of quantitative research on informal employment has a consistently high relevance both in the Russian Federation and in other countries due to its high dependence on cyclicality and crisis stages in economic dynamics of countries with any level of economic development. Developing effective government policy measures to overcome the negative impact of informal employment requires special attention in theoretical and applied research to assessing the factors and conditions of informal employment in the Russian Federation including at the regional level. Such effects of informal employment as a shortfall in taxes, potential losses in production efficiency, and negative social consequences are a concern for the authorities of the federal and regional levels. Development of quantitative indicators to determine the level of informal employment in the regions, taking into account their specifics in the general spatial and economic system of Russia are necessary to overcome these negative effects. The article proposes and tests methods for solving the problem of assessing the impact of hierarchical relationships on macroeconomic factors at the regional level of informal employment in constituent entities of the Russian Federation. Majority of the works on the study of informal employment are based on basic statistical methods of spatial-dynamic analysis, as well as on the now «traditional» methods of cluster and correlation-regression analysis. Without diminishing the merits of these methods, it should be noted that they are somewhat limited in identifying hidden structural connections and interdependencies in such a complex multidimensional phenomenon as informal employment. In order to substantiate the possibility of overcoming these limitations, the article proposes indicators of regional statistics that directly and indirectly characterize informal employment and also presents the possibilities of using the «random forest» method to identify groups of constituent entities of the Russian Federation that have similar macroeconomic factors of informal employment. The novelty of this method in terms of research objectives is that it allows one to assess the impact of macroeconomic indicators of regional development on the level of informal employment, taking into account the implicit, not predetermined by the initial hypotheses, hierarchical relationships of factor indicators. Based on the generalization of the studies presented in the literature, as well as the authors’ statistical calculations using Rosstat data, the authors came to the conclusion about the high importance of macroeconomic parameters of regional development and systemic relationships of macroeconomic indicators in substantiating the differentiation of the informal level across the constituent entities of the Russian Federation.

Recent Advances and Need of Green Synthesis in Two-Dimensional Materials for Energy Conversion and Storage Applications

2021 ◽  
Vol 16 ◽  
Author(s):  
Joice Sophia Ponraj ◽  
Muniraj Vignesh Narayanan ◽  
Ranjith Kumar Dharman ◽  
Valanarasu Santiyagu ◽  
Ramalingam Gopal ◽  
...  
Keyword(s):  
Energy Storage ◽  
Green Synthesis ◽  
2D Materials ◽  
Synthesis Method ◽  
Energy Storage And Conversion ◽  
Two Dimensional ◽  
Severe Problem ◽  
Energy Conversion And Storage ◽  
Energy Application ◽  
The Impact

: Increasing energy crisis across the globe requires immediate solutions. Two-dimensional (2D) materials are in great significance because of its application in energy storage and conversion devices but the production process significantly impacts the environment thereby posing a severe problem in the field of pollution control. Green synthesis method provides an eminent way of reduction in pollutants. This article reviews the importance of green synthesis in the energy application sector. The focus of 2D materials like graphene, MoS2, VS2 in energy storage and conversion devices are emphasized based on supporting recent reports. The emerging Li-ion batteries are widely reviewed along with their promising alternatives like Zn, Na, Mg batteries and are featured in detail. The impact of green methods in the energy application field are outlined. Moreover, future outlook in the energy sector is envisioned by proposing an increase in 2D elemental materials research.

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