Large-Scale Urban Modeling by Combining Ground Level Panoramic and Aerial Imagery

Author(s):  
Lu Wang ◽  
Suya You ◽  
Ulrich Neumann
Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4112
Author(s):  
Fidel Alejandro Rodríguez-Corbo ◽  
Leyre Azpilicueta ◽  
Mikel Celaya-Echarri ◽  
Peio Lopez-Iturri ◽  
Ana V. Alejos ◽  
...  

The characterization of different vegetation/vehicle densities and their corresponding effects on large-scale channel parameters such as path loss can provide important information during the deployment of wireless communications systems under outdoor conditions. In this work, a deterministic analysis based on ray-launching (RL) simulation and empirical measurements for vehicle-to-infrastructure (V2I) communications for outdoor parking environments and smart parking solutions is presented. The study was carried out at a frequency of 28 GHz using directional antennas, with the transmitter raised above ground level under realistic use case conditions. Different radio channel impairments were weighed in, considering the progressive effect of first, the density of an incremental obstructed barrier of trees, and the effect of different parked vehicle densities within the parking lot. On the basis of these scenarios, large-scale parameters and temporal dispersion characteristics were obtained, and the effect of vegetation/vehicle density changes was assessed. The characterization of propagation impairments that different vegetation/vehicle densities can impose onto the wireless radio channel in the millimeter frequency range was performed. Finally, the results obtained in this research can aid communication deployment in outdoor parking conditions.


2007 ◽  
Vol 46 (4) ◽  
pp. 445-456 ◽  
Author(s):  
Katherine Klink

Abstract Mean monthly wind speed at 70 m above ground level is investigated for 11 sites in Minnesota for the period 1995–2003. Wind speeds at these sites show significant spatial and temporal coherence, with prolonged periods of above- and below-normal values that can persist for as long as 12 months. Monthly variation in wind speed primarily is determined by the north–south pressure gradient, which captures between 22% and 47% of the variability (depending on the site). Regression on wind speed residuals (pressure gradient effects removed) shows that an additional 6%–15% of the variation can be related to the Arctic Oscillation (AO) and Niño-3.4 sea surface temperature (SST) anomalies. Wind speeds showed little correspondence with variation in the Pacific–North American (PNA) circulation index. The effect of the strong El Niño of 1997/98 on the wind speed time series was investigated by recomputing the regression equations with this period excluded. The north–south pressure gradient remains the primary determinant of mean monthly 70-m wind speeds, but with 1997/98 removed the influence of the AO increases at nearly all stations while the importance of the Niño-3.4 SSTs generally decreases. Relationships with the PNA remain small. These results suggest that long-term patterns of low-frequency wind speed (and thus wind power) variability can be estimated using large-scale circulation features as represented by large-scale climatic datasets and by climate-change models.


An investigation is made into the excitation of large-scale atmospheric oscillations by the direct absorption of incoming solar radiation by atmospheric ozone. The atmospheric temperature profile is chosen to agree favourably with the main features of the observed temperature distribution, particularly as regards the maximum around the 50 km height; this distribution is shown to be non-resonant as far as the solar semidiurnal component is concerned. The excited solar diurnal, semidiurnal and terdiurnal pressure oscillations are computed and we find that although the largest Fourier component in the heating is the diurnal term , the tide it excites is small in keeping with observation. On the other hand, the excited semidiurnal oscillation is much larger than that due to any previously considered thermal mechanism . It is found that the main semidiurnal and terdiurnal tides generated by the direct absorption of insolation by ozone as calculated in the present work, together with published results regarding water vapour absorption, can adequately account for the observed values at ground level. The seasonal variations of the semi and terdiurnal tides are also calculated and these agree extremely well with observation. Finally, the change of phase of 180° in the vertical distribution of the solar semidiurnal oscillation, which is expected from the analysis of the quiet day magnetic variation, is accounted for in the present work.


2020 ◽  
Vol 10 (4) ◽  
pp. 1061-1067 ◽  
Author(s):  
Amir Mohammad Moradi Sizkouhi ◽  
Mohammadreza Aghaei ◽  
Sayyed Majid Esmailifar ◽  
Mohammad Reza Mohammadi ◽  
Francesco Grimaccia

2021 ◽  
Author(s):  
Sally Jahn ◽  
Elke Hertig

<p>Air pollution and heat events present two major health risks, both already independently posing a significant threat to human health and life. High levels of ground-level ozone (O<sub>3</sub>) and air temperature often coincide due to the underlying physical relationships between both variables. The most severe health outcome is in general associated with the co-occurrence of both hazards (e.g. Hertig et al. 2020), since concurrent elevated levels of temperature and ozone concentrations represent a twofold exposure and can lead to a risk beyond the sum of the individual effects. Consequently, in the current contribution, a compound approach considering both hazards simultaneously as so-called ozone-temperature (o-t-)events is chosen by jointly analyzing elevated ground-level ozone concentrations and air temperature levels in Europe.</p><p>Previous studies already point to the fact that the relationship of underlying synoptic and meteorological drivers with one or both of these health stressors as well as the correlation between both variables vary with the location of sites and seasons (e.g. Otero et al. 2016; Jahn, Hertig 2020). Therefore, a hierarchical clustering analysis is applied to objectively divide the study domain in regions of homogeneous, similar ground-level ozone and temperature characteristics (o-t-regions). Statistical models to assess the synoptic and large-scale meteorological mechanisms which represent main drivers of concurrent o-t-events are developed for each identified o-t-region.</p><p>Compound elevated ozone concentration and air temperature events are expected to become more frequent due to climate change in many parts of Europe (e.g. Jahn, Hertig 2020; Hertig 2020). Statistical projections of potential frequency shifts of compound o-t-events until the end of the twenty-first century are assessed using the output of Earth System Models (ESMs) from the sixth phase of the Coupled Model Intercomparison Project (CMIP6).</p><p><em>Hertig, E. (2020) Health-relevant ground-level ozone and temperature events under future climate change using the example of Bavaria, Southern Germany. Air Qual. Atmos. Health. doi: 10.1007/s11869-020-00811-z</em></p><p><em>Hertig, E., Russo, A., Trigo, R. (2020) Heat and ozone pollution waves in Central and South Europe- characteristics, weather types, and association with mortality. Atmosphere. doi: 10.3390/atmos11121271</em></p><p><em>Jahn, S., Hertig, E. (2020) Modeling and projecting health‐relevant combined ozone and temperature events in present and future Central European climate. Air Qual. Atmos. Health. doi: 10.1007/s11869‐020‐009610</em></p><p><em>Otero N., Sillmann J., Schnell J.L., Rust H.W., Butler T. (2016) Synoptic and meteorological drivers of extreme ozone concentrations over Europe. Environ Res Lett. doi: 10.1088/ 1748-9326/11/2/024005</em></p>


2016 ◽  
Vol 19 (3) ◽  
pp. 222-232 ◽  
Author(s):  
Nehla Ghouaiel ◽  
Sébastien Lefèvre

2018 ◽  
Vol 10 (12) ◽  
pp. 2054 ◽  
Author(s):  
Veronika Gstaiger ◽  
Jiaojiao Tian ◽  
Ralph Kiefl ◽  
Franz Kurz

Large-scale events represent a special challenge for crisis management. To ensure that participants can enjoy an event safely and carefree, it must be comprehensively prepared and attentively monitored. Remote sensing can provide valuable information to identify potential risks and take appropriate measures in order to prevent a disaster, or initiate emergency aid measures as quickly as possible in the event of an emergency. Especially, three-dimensional (3D) information that is derived using photogrammetry can be used to analyze the terrain and map existing structures that are set up at short notice. Using aerial imagery acquired during a German music festival in 2016 and the celebration of the German Protestant Church Assembly of 2017, the authors compare two-dimensional (2D) and novel fusion-based 3D change detection methods, and discuss their suitability for supporting large-scale events during the relevant phases of crisis management. This study serves to find out what added value the use of 3D change information can provide for on-site crisis management. Based on the results, an operational, fully automatic processor for crisis management operations and corresponding products for end users can be developed.


2019 ◽  
Vol 8 (3) ◽  
pp. 103 ◽  
Author(s):  
Julien Lamontagne-Godwin ◽  
Peter Dorward ◽  
Irshad Ali ◽  
Naeem Aslam ◽  
Sarah Cardey

As populations increase, so do the challenges in feeding the world. Rural Advisory Services (RAS) contribute positively to food security by ensuring rural populations have access to vital knowledge increasing yields and rural incomes. For historical reasons however, national RAS have often developed into complex networks of stakeholders which can confuse, and even in some cases provide conflicting advice. In order to improve internal and external knowledge of an advisory service, this article investigates the benefits and limitations of an approach that combines qualitative and quantitative stakeholder perception activities at a local and national level. Local and national workshops were held using focus group and open fora techniques in order to portray and visualise a crop health advisory system in Pakistan, a dynamic and complex case study. The approach manages to expose key differences between local and national perceptions of a crop health RAS: whilst both local and national workshop participants decidedly agree on the importance of local (provincial and district level) extension departments, local perceptions clearly identified the strength and value of private sector and community level interactions. At the national workshop, interpretations of ground level activities were vague, yet their mentions of microcredit initiatives, large scale Non-Government Organisation activities and semi-autonomous institutions demonstrate knowledge at a different scale. This approach demonstrates the value of an accessible methodology to measure and understand RAS. Whilst this approach is a key component in assessing the system’s dynamism prior to any future development initiative, it needs to refine its integration of gendered perceptions.


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