scholarly journals Propagation models for high sites in urban areas

2006 ◽  
Vol 4 ◽  
pp. 345-349 ◽  
Author(s):  
A. Hecker ◽  
M. Neuland ◽  
T. Kuerner

Abstract. Analyses of results from commonly used propagation models applied to UMTS Ultra High Sites in urban environments are presented. Differences between predicted and measured values for a site in Nuernberg are calculated as a function of the distance between base station and mobile station and as a function of the angle of incidence. An assessment of the validity range of the different propagation models is done. Furthermore, an analysis of the accuracy of the classification of building data is presented.

2016 ◽  
Vol 9 (10) ◽  
pp. 5063-5075 ◽  
Author(s):  
Roberto Cremonini ◽  
Dmitri Moisseev ◽  
Venkatachalam Chandrasekar

Abstract. High-spatial-resolution weather radar observations are of primary relevance for hydrological applications in urban areas. However, when weather radars are located within metropolitan areas, partial beam blockages and clutter by buildings can seriously affect the observations. Standard simulations with simple beam propagation models and digital elevation models (DEMs) are usually not able to evaluate buildings' contribution to partial beam blockages. In recent years airborne laser scanners (ALSs) have evolved to the state-of-the-art technique for topographic data acquisition. Providing small footprint diameters (10–30 cm), ALS data allow accurate reconstruction of buildings and forest canopy heights. Analyzing the three weather C-band radars located in the metropolitan area of Helsinki, Finland, the present study investigates the benefits of using ALS data for quantitative estimations of partial beam blockages. The results obtained applying beam standard propagation models are compared with stratiform 24 h rainfall accumulation to evaluate the effects of partial beam blockages due to constructions and trees. To provide a physical interpretation of the results, the detailed analysis of beam occultations is achieved by open spatial data sets and open-source geographic information systems.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Andrew M Rogers ◽  
Andrea S Griffin ◽  
Françoise Lermite ◽  
Berndt van Rensburg ◽  
Carla Archibald ◽  
...  

Abstract The extent to which native species utilize urban environments depends on species responses to multiple threatening processes. Here, we aimed to quantify changes in bird communities in response to changing habitat structure, invasive species and aggressive native species. We conducted surveys in two independently invaded regions with similar patterns of urban development. The study regions were New South Wales (NSW) and Queensland (QLD), Australia. We observed 127 species in NSW and 144 species in QLD. Most species (NSW 83 and QLD 84) are urban adapters making use of some or all urban sub-environments. Urban avoiders, species only found in remnant vegetation, were the second largest group (urban avoiders: NSW 23 and QLD 31). We found the lowest richness in the most urban sites (urban exploiters: NSW 10 and QLD 15). Using generalized linear mixed models, we found a non-significant relationship between species richness and the abundance of aggressive species like the common myna and noisy miners, Manorina melanocephala, but a significant positive correlation with the percentage of shrub cover at a site. As there is a gradual loss of species with increasing urbanization, retaining higher complexity in vegetation structure in urban areas will support large numbers of species and could help mitigate the potential impacts of aggressive urban-adapted species and habitat loss.


2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Agostinho Linhares ◽  
Antonio José Martins Soares ◽  
Marco Antonio Brasil Terada

A base station (BS) antenna operates in accordance with the established exposure limits if the values of electromagnetic fields (EMF) measured in points of maximum exposure are below these limits. In the case of BS in open areas, the maximum exposure to EMF probably occurs in the antenna’s boresight direction, from a few tens to a few hundred meters away. This is not a typical scenery for urban environments. However, in the line of sight (LOS) situation, the region of maximum exposure can still be analytically estimated with good results. This paper presents a methodology for the choice of measurement points in urban areas in order to assess compliance with the limits for exposure to EMF.


Author(s):  
Herman Herman ◽  
Demi Adidrana ◽  
Nico Surantha ◽  
Suharjito Suharjito

The human population significantly increases in crowded urban areas. It causes a reduction of available farming land. Therefore, a landless planting method is needed to supply the food for society. Hydroponics is one of the solutions for gardening methods without using soil. It uses nutrient-enriched mineral water as a nutrition solution for plant growth. Traditionally, hydroponic farming is conducted manually by monitoring the nutrition such as acidity or basicity (pH), the value of Total Dissolved Solids (TDS), Electrical Conductivity (EC), and nutrient temperature. In this research, the researchers propose a system that measures pH, TDS, and nutrient temperature values in the Nutrient Film Technique (NFT) technique using a couple of sensors. The researchers use lettuce as an object of experiment and apply the k-Nearest Neighbor (k-NN) algorithm to predict the classification of nutrient conditions. The result of prediction is used to provide a command to the microcontroller to turn on or off the nutrition controller actuators simultaneously at a time. The experiment result shows that the proposed k-NN algorithm achieves 93.3% accuracy when it is k = 5.


Author(s):  
Philip James

The focus of this chapter is an examination of the diversity of living organisms found within urban environments, both inside and outside buildings. The discussion commences with prions and viruses before moving on to consider micro-organisms, plants, and animals. Prions and viruses cause disease in plants and animals, including humans. Micro-organisms are ubiquitous and are found in great numbers throughout urban environments. New technologies are providing new insights into their diversity. Plants may be found inside buildings as well as in gardens and other green spaces. The final sections of the chapter offer a discussion of the diversity of animals that live in urban areas for part or all of their life cycle. Examples of the diversity of life in urban environments are presented throughout, including native and non-native species, those that are benign and deadly, and the common and the rare.


Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 175
Author(s):  
Jan Geletič ◽  
Michal Lehnert ◽  
Pavel Krč ◽  
Jaroslav Resler ◽  
Eric Scott Krayenhoff

The modelling of thermal exposure in outdoor urban environments is a highly topical challenge in modern climate research. This paper presents the results derived from a new micrometeorological model that employs an integrated biometeorology module to model Universal Thermal Climate Index (UTCI). This is PALM-4U, which includes an integrated human body-shape parameterization, deployed herein for a pilot domain in Prague, Czech Republic. The results highlight the key role of radiation in the spatiotemporal variability of thermal exposure in moderate-climate urban areas during summer days in terms of the way in which this directly affects thermal comfort through radiant temperature and indirectly through the complexity of turbulence in street canyons. The model simulations suggest that the highest thermal exposure may be expected within street canyons near the irradiated north sides of east–west streets and near streets oriented north–south. Heat exposure in streets increases in proximity to buildings with reflective paints. The lowest heat exposure during the day may be anticipated in tree-shaded courtyards. The cooling effect of trees may range from 4 °C to 9 °C in UTCI, and the cooling effect of grass in comparison with artificial paved surfaces in open public places may be from 2 °C to 5 °C UTCI. In general terms, this study illustrates that the PALM modelling system provides a new perspective on the spatiotemporal differentiation of thermal exposure at the pedestrian level; it may therefore contribute to more climate-sensitive urban planning.


2021 ◽  
Vol 11 (5) ◽  
pp. 2057
Author(s):  
Abdallah Namoun ◽  
Ali Tufail ◽  
Nikolay Mehandjiev ◽  
Ahmed Alrehaili ◽  
Javad Akhlaghinia ◽  
...  

The use and coordination of multiple modes of travel efficiently, although beneficial, remains an overarching challenge for urban cities. This paper implements a distributed architecture of an eco-friendly transport guidance system by employing the agent-based paradigm. The paradigm uses software agents to model and represent the complex transport infrastructure of urban environments, including roads, buses, trolleybuses, metros, trams, bicycles, and walking. The system exploits live traffic data (e.g., traffic flow, density, and CO2 emissions) collected from multiple data sources (e.g., road sensors and SCOOT) to provide multimodal route recommendations for travelers through a dedicated application. Moreover, the proposed system empowers the transport management authorities to monitor the traffic flow and conditions of a city in real-time through a dedicated web visualization. We exhibit the advantages of using different types of agents to represent the versatile nature of transport networks and realize the concept of smart transportation. Commuters are supplied with multimodal routes that endeavor to reduce travel times and transport carbon footprint. A technical simulation was executed using various parameters to demonstrate the scalability of our multimodal traffic management architecture. Subsequently, two real user trials were carried out in Nottingham (United Kingdom) and Sofia (Bulgaria) to show the practicality and ease of use of our multimodal travel information system in providing eco-friendly route guidance. Our validation results demonstrate the effectiveness of personalized multimodal route guidance in inducing a positive travel behavior change and the ability of the agent-based route planning system to scale to satisfy the requirements of traffic infrastructure in diverse urban environments.


1998 ◽  
Author(s):  
Bing Zhang ◽  
Jiangui Liu ◽  
Xiangjun Wang ◽  
Changshan Wu

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1845
Author(s):  
Andreas Zehnsdorf ◽  
Keani C. U. Willebrand ◽  
Ralf Trabitzsch ◽  
Sarah Knechtel ◽  
Michael Blumberg ◽  
...  

While constructed wetlands have become established for the decentralized treatment of wastewater and rainwater, wetland roofs have only been built in isolated cases up to now. The historical development of wetland roofs is described here on the basis of a survey of literature and patents, and the increasing interest in this ecotechnology around the world is presented. In particular, this article describes the potential for using wetland roofs and examines experience with applications in decentralized water management in urban environments and for climate regulation in buildings. Wetland roofs are suitable as a green-blue technology for the future—particularly in cities with an acute shortage of unoccupied ground-level sites—for the decentralized treatment of wastewater streams of various origins. Positive “side effects” such as nearly complete stormwater retention and the improvement of climates in buildings and their surroundings, coupled with an increase in biodiversity, make wetland roofs an ideal multi-functional technology for urban areas.


Sign in / Sign up

Export Citation Format

Share Document