In recent years, proper management of resource and timing for emergency evacuation of citizens from the site of terrorist attack has been widely considered by researchers in the field of urban planning. Little studies which have carried out on modeling the behavior of citizens and terrorists in urban environment generally focused on terrorist's behavior. Although different age groups show different abilities in emergencies rised by terrorist attack, in those studies, citizens are modeled in only one group of age. The main purpose of this study is to develope an agent-based model to simulate emergency evacuation due to terrorist attacks considering available infrastructure of a city. In order to evaluate the potential terrorist attack in a city, the behaviour of three groups of agents, including civilians, defense forces, and terrorists, are developed and simulated. In this regard, by examining different scenarios, it is possible to minimize the casualties caused by terrorist attack and rapid evacuation. To perform sensibility analysis and determine the most sensitive parameters, One-at-a-time method is hereby employed. NetLogo software is also used to develop and implement the proposed agent-based model.As a case study, the presented agent-based model has been implemented under various scenarios in district 6 of Tehran and the results have been analyzed. Based on the results of analyzing difference scenarios, it is possible to minimize the possibility of terrorist attack by increasing the number of defense forces. Another useful scenario is to allocate 60% of the defense forces to protect the busy and safe areas and 40% to search for and stop terrorist agents in the study area, the number of terrorist attacks and the number of deaths will cut in half.
ABSTRACT:High local groundwater flow into rock tunnels may lead to a potential hazard and is an important factor influencing construction time and costs. Geological features such as fault zones and open fractures can be the source of very high local groundwater inflows. Having a reliable estimation of location groundwater inflows is essential before excavation of tunnels. To reduce the costs and time of field works, remote sensing investigations can be a good solution. The main aim of the present study is to propose a methodology for detecting the geomorphic markers of cuesta in the high local groundwater inflow to Nosoud tunnel using the satellite imagery data. For this purpose, a reflectance image from the ASTER satellite sensor was used. Our Experiments show that cuesta springs, caused by hydraulic fracturing, can be detected using the normalized difference vegetation index (NDVI) map, computed on the ASTER image, and analyzing the topographic and morphometric features of the area. Moreover, observations in tunnel excavation stage showed that crossing through open fractures in hard and thick layers is the major cause of water inflow into the tunnel, which corresponds to the surface hydrogeological evidences obtained from the ASTER image.
ABSTRACT:Estimating the height of trees is one of the most important applications of polarimetrc interferometric synthetic aperture Radar (PolInSAR). PolInSAR requires an appropriate estimation of the interferogram coherence for obtaining the best results. Actually, the coherence estimation has a great impact on PolInSAR results for estimating the height of trees. Generally, the random volume over ground (RVOG) model is used for forest height estimation. In the ROVG, interferogram coherence entered as one of the observations. For coherence estimation, selecting the best window size conventionally is done by the coherence bias and convergence (CBC) method, which requires user experience and visual analysis. This study presents a fast and straightforward method to calculate the best value of the window size without affecting the user experience and visual analysis. In this study, we compare the performance of tree height estimation for the CBC and the proposed method on three simulated PolInSAR data in a forestry region. Experimental results obtained for estimating the height of trees show that, the window size values obtained by the proposed method are the same as those values obtained by the CBC method. Moreover, results suggest that the proposed method is faster and more stability than the CBC method.
Aims: Using a latitude dependent local corrected model and based on MODIS data around Mehrabad Synoptic Station of Tehran, the spectral radiance in long wavelength infrared region was modeled and calculated for total upward and downward radiation flux and direct downward radiation flux for cold and hot seasons. Study Design: Design of the study includes the calculations of local atmospheric profile of the subjected region by radiosonde data, calculations of the atmospheric profile by MODIS data for same region. It presents a latitude dependent relation for modifying the MODIS data of any point which properly could be used instead of radiosonde data at that point and finally model and calculate LWIR’s total emitted flux at different heights for the area around subjected region with local profile for both hot (June, July, August) and cold (January, February, March) seasons.[G7] [G8] Place and Duration of Study: Department of Optic and Laser, Faculty of science, I. H.U University, between February 2016 and December 2017. Methodology: The radiosonde and MODIS raw data of 13 stations with different latitudes in 1995-2015 were used for modification purpose. By applying statistic calculations on raw data, the atmospheric profile was extracted. Radiosonde data were not available in any points of a region, while the MODIS data were available. A latitude dependent relation is presented in this work for modifying the MODIS data of any point which properly could be used instead of radiosonde data at that point. Results: The results were compared and assessed with the default profiles of sub-arctic winter and tropical models. The RMSEs for total upward, downward, and direct radiation fluxes in terms of wavelength in long wavelength infrared in cold and hot seasons were 2.45 Wm-2µ-1 and 1.722 Wm-2µ-1, respectively. Conclusion: The results showed that local atmospheric profile plays a key role in modifying atmospheric effects on TIR hyperspectral radiance and their accurate understanding improves the quality and quantity of the radiances reaching a sensor and helps better detection of the spectral signature of the study objectives.
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