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Showing 2 results for Fuzzy Logic

Farhad Azizpour, Vahid Riahi, Ali Moazeni,
Volume 1, Issue 3 (10-2014)
Abstract

Environmental hazards are considered as one of the main obstacles for achieving sustainable human settlements development (particularly in rural areas). Today, with a new look at crisis management, using all managerial, organizational and planning accomplishments before the crisis, is an essential and rational concern. Rural settlements of the country along with cities always are threatened by a variety of environmental hazards, but what makes these spaces different from the cities is the high-intensity of vulnerability due to its physical decay texture. In this regard, one of the key elements in confronting the possible crisis that must be taken into account is the crisis management bases in which all prevention, preparedness and response measures, including disaster relief, temporary accommodation for the injured, etc. is provided and minimizes the consequences of potential crisis. Being located in the Kahrizak fault zone and the placement of hazardous industries in this region, is the main reason for selecting Kahrizak district as a study area in this research.    To achieve goals of constructing crisis management bases which indeed is the tactic ability of crisis management system (CMS), it is required to set the site selection criteria and standards for constructing them in such a way that provide more operational activities and develop the level of their impacts. In this regard, in the first step, the final criteria for site selection of crisis management base were selected after reviewing previous studies. Then, after surveying the experts and also the localization of criteria on the basis of area condition, seventeen final criteria were determined. For quantitative criteria, data were collected through organizations and reference centers and for a single qualitative criterion (cultural convergence), the questionnaire instrument used in gathering data. After collecting data using library and field methods, a combination of two models: fuzzy logic and hierarchical analysis process (AHP) applied for optimal location of crisis management base.    To determine the impact level of each criterion in the site selection process in two above-mentioned models, the standards for each of the seventeen criteria was determined with the help of combination method. The standards of some of the criteria determined using the standards in related organizations and some other standards proposed by experts and also through the localization by the researcher. Afterward, initially fuzzy standardized common scale maps produced from all information layers in a raster format. Then selected criteria by experts in the format of AHP model were compared with each other through pairwise comparison method. As a result of this comparison, the weight of criteria was determined which indicates the preference degree of each criterion over the others. At last, all standardized (fuzzified) layers multiplied in each of the final weight resulting from Analytical Hierarchy Model and in total converted into weighted fuzzy layers. In the next step, following the process of fuzzy model, fuzzy addition and multiplication operators were applied on output layers. Finally, to modify the layer resulting from fuzzy addition and multiplication, the Gamma operator was used. As such, after producing layers of different fuzzy gammas, essential assessment was conducted for selecting appropriate and ideal gamma. In order to do this, produced layers of each fuzzy gammas were compared with the study area for optimal location and the establishment of crisis management base. Since the gamma 0.9 had the most conformity to suitable zone in the layers of study area, it was selected as the appropriate gamma. However, to ensure the selected location, field study was conducted.     According to the research findings, the following conclusions were obtained: Site selection criteria for rural crisis management base not only has an environmental essence (built and natural), but socio –economic criteria are important as well Effective criteria for site selection of rural crisis management base, affected by regional and local requirements are not the same. Localization of criteria is a necessity that should be considered in site selection. Standards based on site selection criteria depending on the type of services, goals and location at multiple spatial levels (regional, local, urban and rural) is different: in the other words one size does not fit all Site selection is not only based on the location within overlaying information layers by using the models, but the final choice is done after field evaluation and visit.


Alireza Khosravi, Mehdi Azhdary Moghaddam, Seyed Arman Hashemi Monfared, Hamid Nazaripour,
Volume 9, Issue 4 (3-2023)
Abstract


Comparison of Results of GIS-Based Multicriteria Decision Analysis and Remote Sensing Indicators in Kahir River Basin, Iran.

Alireza Khosravi1, Mehdi Azhdary Moghaddam2*, Seyed Arman Hashemi Monfared3,
 Hamid Nazaripour4

1. M.Sc. Department of Civil Engineering, University of Sistan and Baluchestan, Zahedan, Iran
2. Professor, Department of Civil Engineering, University of Sistan and Baluchestan, Zahedan, Iran
3. Associate professor, Department of Civil Engineering, University of Sistan and Baluchestan, Zahedan, Iran
4.Assistant professor, Department of Physical Geography, University of Sistan and Baluchestan, Zahedan, Iran.


Abstract
Flood risk maps and Flood zoning techniques are useful tools to manage this hazard in the catchment and mitigation of flood impacts. In South Baluchestan and Kahir Basin, due to the existence of winter and summer precipitation regimes, the occurrence of flash floods is inevitable due to the establishment of rural communities and settlements in flood-prone areas, the flooding has caused many damages to the region's vulnerable population. In order to zone flood risk and prepare flood risk maps, climatic data, hydrological, land cover, and topography of the basin were prepared from reliable sources and according to scientific studies, 12 variables affecting flood risk in the form of five main components (Hydrology, vegetation, land cover, climate, and topography) were prepared. According to the regional conditions of the basin, using the opinions of experts based on scientific methods, the weight of each variable and component was determined by Analytical Hierarchy Process(AHP). Using two methods of fuzzy overlay, Weighted Overlay, and the Geographical Information System facilities, a map of variables and components was prepared after reclassification and fuzzy membership function with appropriate operators. The results showed that the fuzzy overlay method concerning its dominant logic has a better distinction of flood-prone areas and can help determine flood hazard micro-zonation in the drainage basins like the Kahir basin. By comparing the results from the real data of the January 2020 flood obtained from satellite images. Due to poor infrastructure and high economic, the risk of flooding may be more harmful and widespread in the future.

Keywords: Flood, Fuzzy logic, Weighted overlay, Southern Baluchestan, GIS.
 

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