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Showing 3 results for Vikor

Abolfazl Ghanbari, Ali Zolfi,
Volume 1, Issue 4 (1-2015)
Abstract

In advance crisis management of natural disasters, particularly earthquakes in urban areas is one of the necessities of urban planning. However, nowadays with the help of technology we can determine the risk of crisis in the urban areas and settlements. Due to population growth and increasing urbanization, the occurrence of natural disasters such as earthquake can cause terrible disasters in the cities. The need to reduce the vulnerability of the cities is one of the main objectives of physical planning of urban areas and city designing. The city of Kashmar in one of Iran's earthquake-prone areas (due to its adjacency to the Lut fault)  has  witnessed the sever destruction from  the September 25, 1903 earthquake (with a magnitude MS= 5/9) and Torbat Haidariye earthquake on 25 May 1923 (a magnitude MS= 5/8). It is very important to identifying vulnerable areas to earthquakes in advance. Accordingly the objective of this study is to identify the vulnerability of urban areas of  Kashmar city to the earthquake by using VIKOR model of urban planning. The vulnerability of the city was computed on several parameters among which the population density is the most important one.

     In order to carry out the research eleven population and other indices were used. These indices are as follows:

  1. Building Materials;
  2.  The quality of the building;
  3. Old buildings;
  4. Number of floors;
  5. The materials of facades of building;
  6. Compatibility of land uses;
  7. Access to network passages;
  8. Distance from the main fault;
  9. The building density;
  10. Numbers of population; and
  11.   Relief and rescue centers.

 By using the VIKOR ranking model the vulnerability of the urban areas of the city was identified and classified. The correlation between the city vulnerability and each of these indices was calculated. The impact of the indices on the city vulnerability was calculated according to the AHP model.

      The results of the study showed that the zone 3 had the highest and the zone 8 had the lowest physical vulnerability in the model. Based on the results of the Spearman correlation, the impact of the population on the vulnerability was about .5866 which is relatively noteworthy.  This means that highest degree of vulnerability can occur in very populated areas of the city. All of the city was regionalized according to the degree of vulnerability to earthquake.

The lack of amenities and facilities such as health centers, fire stations, building materials and weak areas within the city will increase the losses and casualties. It is noteworthy that comprehensive city planning in the future must improve and the needed facilities should be provided. In addition providing services to the residents, especially in critical times after the earthquake should be provided.


Ali Ahmadabadi, Abdolah Seif, Somaye Khosravi, Amanalah Fathnia,
Volume 2, Issue 2 (7-2015)
Abstract

Land degradation in arid, semi-arid and sub-humid areas, leads to  desertification and land degradation is a concept that refers to any reduction of soil potentials. In Iran, that 85 percent of its area is classified in arid and semi-arid climates, and  one percent per annum growth rate of desertification and its increasing trends, finding ways to evaluate this phenomenon and its causes in the form of models seems essential. In Iran, especially southern areas due to their arid climatic conditions, are considered to be areas prone to desertification. This study aims to evaluate and analyze the vulnerability of desertification in the Mond watershed located in the northern coast of the Persian Gulf.

     In order to evaluate the potentials of desertification in the Mond watershed, geological, the erosion (water erosion potential), rainfall, slope, elevation levels and land use maps are used.  To identify vegetation cover conditions Landsat ETM + sensor data and normalized vegetation index (NDVI) are used.

     Where in reflected in the near-infrared band (Band 4, Landsat ETM+) and the reflection in the visible band (band 3 sensor ETM+) respectively. Overlaps and combines the above criteria is done using E-VIKOR (VIKOR developed) a method of multi-criteria decision-making models (MCDM). This method is based on a compromise plan proposed in the compromise solution is justified determines solutions that are as close to the ideal solution and has been created through special credit decision-makers. VIKOR use linear approach normal. The normal value in VIKOR  is not related method unit of measure. Also standardization effective indicators of desertification has been done using a linear scale.

      In this study, the ANP method (Analytical Network Process) was used for weighting criteria. Analysis method Network, is one of the popular methods of multi-criteria decision problems. This method complex relationship between and among the elements of the decision by replacing hierarchical network structure considers. Table 1 shows the weights of the effective criteria in desertification. In this study 7 criteria are used that results show criteria’s of climate and vegetation, have the most effective measures in the area of desertification and erosion (water and wind) have the least amount of importance in the region.

Table 1: weight criteria of effectivein desertification

criteria

vegetation

erosion

Precipitation

Landuse

Geology

Slope

Elevation levels

weight(W)

0.21

0.18

0.15

0.14

0.13

0.11

0.08

    After mapping the effective indicators in evaluating desertification separately, Standardization of maps, weighting the index, To obtain amount and   , Finally, the amount of , was produced Zoning map of desertification that in it Mond watershed in the province Bushehr in terms of desertification is divided into five ratio and the area is provided in Table 2.

Table 1: Percentage and  area zone of desertification

amount vulnerabilities

Area (ha)

Area (in percent)

Very low

516300

11

low

598900

13

Average

1438025

30

High

2168675

46

Very High

40825

1

    Studies show that more than half of the Mond basin have on the surface with average risk of desertification and In the continuation of the current trend of soil degradation, desertification prone zones and will be reduced all lead to the deterioration of the natural ecosystems and human life quality.


Ali Eshghei, Hossein Nazmfar, Ata Gafari,
Volume 7, Issue 2 (8-2020)
Abstract


Spatial analysis physical resiliency City Earthquake Model Condorcet
Case study: ten districts of the region one of Tehran
 
Abstract
Earthquake as one of the most devastating and destructive natural hazards; especially in developing countries, it has been a long time ago With the collapse of buildings and urban infrastructure, Imports a lot of damage to property and assets in urban areas and around them. In response to this, international organizations' strategies to mitigate disasters have made their societies resilient to natural disasters. And considers it within the framework of the Higgo for the years 2005-2015. In fact, the goal of this approach is to reduce the vulnerability of cities and to strengthen citizens' abilities to deal with the dangers of threats such as natural disasters. Considering that the area of ​​a Tehran city due to its proximity to faults such as Mashaa fault, North Tehran fault Also, the effects of faults in and around the region such as Niavaran fault, Mahmoodieh fault and Darabad fault (Banamieh) are located in a region with a high seismic hazard. Assessment of resilience of the region to earthquake risk and resilience of the region In order to reduce the risks of earthquakes in this area is very important. Accordingly, the present study was conducted with the aim of assessing the resilience situation of the 10th district of Tehran municipality district against earthquake.
The method of this research is descriptive-analytical with a purposeful purpose. The research area of ​​the 10th Region is a municipality of Tehran. The raw data used by the Tehran Municipality Information Technology Organization has been obtained. To determine the relative importance of each component used in research According to experts from the Urban Planning Area, the Network Analysis Process (ANP) has been used in the form of Super Decisions software. Then, to rank 10 areas of a Tehran municipality district against earthquake, Multi-criteria decision making models (MCDMs) including TOPSIS, VIKOR, HAW and SAW models have been used. Considering that different methods have been used to rank the areas Different results have been achieved, to overcome the contradictions between the various ratings of the regions in each of the models,
and a single result has been used to rank the areas of the congregation's integrated model.
Finally, in order to speak, the results of the model used in the ArcGIS environment were mapped.
In this research, for the spatial analysis of the resilience of the 10 district areas of a Tehran municipality from the results four models (TOPSIS, VIKOR, HAW and SAW) were used. Based on the results of the TOPSIS technique, areas 8, 3 and 2 of resilience are large, areas 7 and 4 of the moderate resilience, Areas 5, 1, 6 and 10 have low resilience and area 9 has very little resilience against the earthquake. Based on the results of the VIKOR model, areas 3 and 4 of the resilience, regions 2, 7, 5, 9, 8, 6 and 10 of the moderate resilience Medium and area one have low resilience against earthquake. Based on the results of the HAW model, area 3 of the high resilience, regions 2, 7, 8 and 4 of the moderate resilience and areas 10, 1, 6 and 9 are of low resilience. In this model, no area has been found to be very resilient. Based on the results of the SAW model, regions 3, 2, 8, and 7 are in the range of many resiliences, regions 5 and 4 in the moderate resilience range, Area 9 is in the low resilience range and areas 10, 6 and 1 are in the low resilience range against earthquakes.

In this study, we evaluated the resilience situation in the districts of Tehran municipality district in an earthquake Multi-criteria decision-making methods including TOPSIS, VIKOR, HAW and SAW were used, Then a CONDORCET integrated model was used to achieve a single result of these analyzes. The results of the Canadian model, which is the result of a combination of the final results of the models (Tapis, VIKOR, HAW and SAW), show that Areas 2, 4, 5, and 3 are of high resilience, areas 7, 8 and 1 of the moderate resilience, 10 and 6 of the resilience, and area 9 of the resilience is very low against earthquakes. Which should be prioritized in future plans. Although it is possible to assess the vulnerability of urban areas by using different models and mapping them in the region's resilience to the earthquake crisis, a significant part of post-crisis casualties fell but this will not be achieved until the authorities are seriously determined.
 
Keywords: Resilience, Earthquake, Multi-criteria Decision Making Methods, Tehran Municipality Area
 
 


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