scholarly journals Experimental Validation of Gaussian Process-Based Air-to-Ground Communication Quality Prediction in Urban Environments

Sensors ◽  
2019 ◽  
Vol 19 (14) ◽  
pp. 3221 ◽  
Author(s):  
Pawel Ladosz ◽  
Jongyun Kim ◽  
Hyondong Oh ◽  
Wen-Hua Chen
Keyword(s):  
Gaussian Process ◽  
Urban Environment ◽  
Urban Environments ◽  
World City ◽  
Model Parameters ◽  
Communication Model ◽  
Channel Prediction ◽  
Model Based ◽  
Communication Signal ◽  
Prediction Approach

This paper presents a detailed experimental assessment of Gaussian Process (GP) regression for air-to-ground communication channel prediction for relay missions in urban environment. Considering restrictions from outdoor urban flight experiments, a way to simulate complex urban environments at an indoor room scale is introduced. Since water significantly absorbs wireless communication signal, water containers are utilized to replace buildings in a real-world city. To evaluate the performance of the GP-based channel prediction approach, several indoor experiments in an artificial urban environment were conducted. The performance of the GP-based and empirical model-based prediction methods for a relay mission was evaluated by measuring and comparing the communication signal strength at the optimal relay position obtained from each method. The GP-based prediction approach shows an advantage over the model-based one as it provides a reasonable performance without a need for a priori information of the environment (e.g., 3D map of the city and communication model parameters) in dynamic urban environments.

Relationships

2018 ◽  
Author(s):  
Philip James
Keyword(s):  
Urban Environment ◽  
Companion Animals ◽  
Domestic Animals ◽  
Urban Environments ◽  
Select Group ◽  
Exotic Pets

Relationships between organisms within urban environments are many and varied. Plants are found in many households, and in addition to the benefits derived from their decorative properties, they also purify the air by removing pollutants. Over the course of history some animals have become domesticated: cows, horses, goats, providing food and transport. Of these, a select group have become companions (cats, dogs, and more exotic pets). Such domesticated and companion animals are an important part of the overall biology of urban environments and these relationships are explored and discussed. Some former companion or domestic animals have become feral, and other animals have never been domesticated and live freely in the urban environment. Some of these animals have beneficial relationships with humans whereas others are parasitic or are considered pests. These relationships are the focus for the later part of the exploration set out in this chapter.

What is the urban environment and what is biology?

2018 ◽  
Author(s):  
Philip James
Keyword(s):  
Urban Environment ◽  
Urban Environments ◽  
First Century ◽  
Final Part ◽  
Global Spread ◽  
Twenty First Century ◽  
Genes To Ecosystems ◽  
Micro Organisms ◽  
Initial Focus

The two main themes contained within the title The Biology of Urban Environments are explored. The initial focus is on urban environments. A discussion of the origins of cities and the global spread of urbanization leads on to a consideration of urban environments in the twenty-first century. In the second section, the focus switches to biology. The scope of the discipline is set out in terms of both the range of sub-disciplines and of biological scales. It is established from this discussion that in this book the topics considered span from genes to ecosystems and will be illustrated by examples of the biology of micro-organisms, plants, and animals. Importantly humans will be included within this consideration: our biology is affected by urban environments. The final part presents the structure of the book.

scholarly journals A Model-Based Tool for Assessing the Impact of Land Use Change Scenarios on Flood Risk in Small-Scale River Systems—Part 1: Pre-Processing of Scenario Based Flood Characteristics for the Current State of Land Use

Hydrology ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 102
Author(s):  
Frauke Kachholz ◽  
Jens Tränckner
Keyword(s):  
Land Use ◽  
River Flow ◽  
Land Use Changes ◽  
Small Rivers ◽  
Small Scale ◽  
Model Parameters ◽  
Ungauged Catchments ◽  
Model Based ◽  
Current State ◽  
The Impact

Land use changes influence the water balance and often increase surface runoff. The resulting impacts on river flow, water level, and flood should be identified beforehand in the phase of spatial planning. In two consecutive papers, we develop a model-based decision support system for quantifying the hydrological and stream hydraulic impacts of land use changes. Part 1 presents the semi-automatic set-up of physically based hydrological and hydraulic models on the basis of geodata analysis for the current state. Appropriate hydrological model parameters for ungauged catchments are derived by a transfer from a calibrated model. In the regarded lowland river basins, parameters of surface and groundwater inflow turned out to be particularly important. While the calibration delivers very good to good model results for flow (Evol =2.4%, R = 0.84, NSE = 0.84), the model performance is good to satisfactory (Evol = −9.6%, R = 0.88, NSE = 0.59) in a different river system parametrized with the transfer procedure. After transferring the concept to a larger area with various small rivers, the current state is analyzed by running simulations based on statistical rainfall scenarios. Results include watercourse section-specific capacities and excess volumes in case of flooding. The developed approach can relatively quickly generate physically reliable and spatially high-resolution results. Part 2 builds on the data generated in part 1 and presents the subsequent approach to assess hydrologic/hydrodynamic impacts of potential land use changes.

Gaussian Process emulation of multi-model ice sheet and glacier projections

2021 ◽  
Author(s):  
Tamsin Edwards ◽  
Keyword(s):  
Gaussian Process ◽  
Sea Level Rise ◽  
Sea Level ◽  
Climate Models ◽  
Ice Sheet ◽  
Surface Air Temperature ◽  
Model Parameters ◽  
Gaussian Process Emulation ◽  
Model Ensembles ◽  
Global Mean

<p><strong>The land ice contribution to global mean sea level rise has not yet been predicted with ice sheet and glacier models for the latest set of socio-economic scenarios (SSPs), nor with coordinated exploration of uncertainties arising from the various computer models involved. Two recent international projects (ISMIP6 and GlacierMIP) generated a large suite of projections using multiple models, but mostly used previous generation scenarios and climate models, and could not fully explore known uncertainties. </strong></p><p><strong>Here we estimate probability distributions for these projections for the SSPs using Gaussian Process emulation of the ice sheet and glacier model ensembles. We model the sea level contribution as a function of global mean surface air temperature forcing and (for the ice sheets) model parameters, with the 'nugget' allowing for multi-model structural uncertainty. Approximate independence of ice sheet and glacier models is assumed, because a given model responds very differently under different setups (such as initialisation). </strong></p><p><strong>We find that limiting global warming to 1.5</strong>°<strong>C </strong><strong>would halve the land ice contribution to 21<sup>st</sup> century </strong><strong>sea level rise</strong><strong>, relative to current emissions pledges: t</strong><strong>he median decreases from 25 to 13 cm sea level equivalent (SLE) by 2100. However, the Antarctic contribution does not show a clear response to emissions scenario, due to competing processes of increasing ice loss and snowfall accumulation in a warming climate. </strong></p><p><strong>However, under risk-averse (pessimistic) assumptions for climate and Antarctic ice sheet model selection and ice sheet model parameter values, Antarctic ice loss could be five times higher, increasing the median land ice contribution to 42 cm SLE under current policies and pledges, with the 95<sup>th</sup> percentile exceeding half a metre even under 1.5</strong>°<strong>C warming. </strong></p><p><strong>Gaussian Process emulation can therefore be a powerful tool for estimating probability density functions from multi-model ensembles and testing the sensitivity of the results to assumptions.</strong></p>

Study On Automatic Adaptation for Control-Oriented Model of Advanced Diesel Engine

2021 ◽  
Author(s):  
Shunki Nishii ◽  
Yudai Yamasaki
Keyword(s):  
Operating Conditions ◽  
Physical Models ◽  
Model Parameters ◽  
Training Methods ◽  
Model Based Control ◽  
Practical Applications ◽  
Model Based ◽  
Automatic Adaptation ◽  
Automobile Engines ◽  
Adaptation Method

Abstract To achieve high thermal efficiency and low emission in automobile engines, advanced combustion technologies using compression autoignition of premixtures have been studied, and model-based control has attracted attention for their practical applications. Although simplified physical models have been developed for model-based control, appropriate values for their model parameters vary depending on the operating conditions, the engine driving environment, and the engine aging. Herein, we studied an onboard adaptation method of model parameters in a heat release rate (HRR) model. This method adapts the model parameters using neural networks (NNs) considering the operating conditions and can respond to the driving environment and the engine aging by training the NNs onboard. Detailed studies were conducted regarding the training methods. Furthermore, the effectiveness of this adaptation method was confirmed by evaluating the prediction accuracy of the HRR model and model-based control experiments.

scholarly journals Calibration and evaluation of a semi-distributed watershed model of Sub-Saharan Africa using GRACE data

2012 ◽  
Vol 16 (9) ◽  
pp. 3083-3099 ◽  
Author(s):  
H. Xie ◽  
L. Longuevergne ◽  
C. Ringler ◽  
B. R. Scanlon
Keyword(s):  
Regional Scale ◽  
Water Storage ◽  
Hydrologic Model ◽  
Sub Saharan Africa ◽  
Model Parameters ◽  
Total Water ◽  
Discharge Data ◽  
Model Based ◽  
Grace Data ◽  
Sub Saharan

Abstract. Irrigation development is rapidly expanding in mostly rainfed Sub-Saharan Africa. This expansion underscores the need for a more comprehensive understanding of water resources beyond surface water. Gravity Recovery and Climate Experiment (GRACE) satellites provide valuable information on spatio-temporal variability in water storage. The objective of this study was to calibrate and evaluate a semi-distributed regional-scale hydrologic model based on the Soil and Water Assessment Tool (SWAT) code for basins in Sub-Saharan Africa using seven-year (July 2002–April 2009) 10-day GRACE data and multi-site river discharge data. The analysis was conducted in a multi-criteria framework. In spite of the uncertainty arising from the tradeoff in optimising model parameters with respect to two non-commensurable criteria defined for two fluxes, SWAT was found to perform well in simulating total water storage variability in most areas of Sub-Saharan Africa, which have semi-arid and sub-humid climates, and that among various water storages represented in SWAT, water storage variations in soil, vadose zone and groundwater are dominant. The study also showed that the simulated total water storage variations tend to have less agreement with GRACE data in arid and equatorial humid regions, and model-based partitioning of total water storage variations into different water storage compartments may be highly uncertain. Thus, future work will be needed for model enhancement in these areas with inferior model fit and for uncertainty reduction in component-wise estimation of water storage variations.

Research on Network Communication Model of Intelligent Ship Handling Simulator

2011 ◽  
Vol 97-98 ◽  
pp. 787-793 ◽  
Author(s):  
Shen Hua Yang ◽  
Guo Quan Chen ◽  
Xing Hua Wang ◽  
Yue Bin Yang
Keyword(s):  
Mathematical Model ◽  
Degrees Of Freedom ◽  
Communication Process ◽  
Network Communication ◽  
Communication Model ◽  
Test Results ◽  
Six Degrees Of Freedom ◽  
Model Based ◽  
Hydraulic Servo ◽  
Ship Handling

Due to the target ship in the traditional ship handling simulator have not the ability to give way to other ships automatically to avoid collision, this paper put forward a new idea that bringing the hydraulic servo platform, six degrees of freedom ship mathematical model, the actual traffic flow, researching achievement of automatic anti-collision in research of the new pattern ship handling simulator, and successfully develop the Intelligent Ship Handling Simulator(ISHS for short). The paper focuse on the research on the network communication model of ISHS. We took the entire simulator system as three relatively independent networks, proposed a framework of communication network that combined IOCP model based on TCP with blocking model based on UDP, and gave the communication process and protocols of system. Test results indicate that this is an effective way to improve the ownship capacity of ship handling simulator and meet the need of multi-ownship configuration of desktop system of ship handling simulator.

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