Earthquake risk in urban street network : an example from region 6 of Tehran, Iran

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Purpose – Zone 6 of Tehran, with a populations of 220,000 people (3.6 per cent of the city population) and 20 km2 area (3 per cent of the city area), is one of the main municipal zones of Tehran. Major land-uses, like ministries, embassies, universities, general hospitals and medical centers, big financial firms, and so on, manifest the high importance of this region on a local and national scale. Thus, it is necessary to pay close attention to issues concerning crisis management in this area. Design/methodology/approach – In this paper, by using indexes such as access to medical centers, street inclusion, building and population density, land-use, peak ground acceleration and building quality, vulnerability degree of street networks in zone 6 against the earthquake is calculated through overlaying maps and data in combination with inversion hierarchical weight process method and geographic information systems. Findings – This article concludes that buildings alongside the streets with high population and building density, low building quality, far to rescue centers and high level of inclusion represent high rate of vulnerability, compared with other buildings. Also, by moving from north to south of the zone, the vulnerability increases. Likewise, highways and streets with substantial width and low building and population density hold little values of vulnerability. Thus, streets with high level of inclusion, building and population density present further vulnerability. Originality/value – It is expected that the results of this paper be used by the urban decision-makers. Due to high vulnerability of most parts of the urban textures of Tehran, similar researches will have importance for preparation for the future possible earthquakes

Wideband Directional Channel Characterization for Multiuser MIMO Systems Over a Random Rough Dielectric Ground

© 2016 IEEE. In this study, small perturbation method (SPM) and Kirchhoff approximation (KA) are incorporated into ray-tracing (RT) routines to model multiuser multi-input multi-output (MU-MIMO) channels formed on a rough dielectric terrain. The effect of surface roughness and correlation length, solid soil fractions, moisture content, link range, antenna height, polarization, radiation pattern, and carrier frequency are examined on received power, power delay and angular profiles, root mean square (RMS) delay and angular spread, coherence bandwidth, and coherence distance. Quantitative and qualitative analyses reveal that antenna directionality and terrain undulation and textural composition have significant impacts on the received signal power and channel multipath parameters and, hence, the performance of MU-MIMO terrain-based communication systems