نشریه مطالعات ساختار و کارکرد شهری
پیاپی 21 (زمستان 1398)

Density as one of the dimensions of city construction is an important factor in understanding how the city works and changes. in the case of the study.the city of urmia has been developing a large horizontal expansion in the recent decades.The purpose of this research is to evaluate the process of change in the types of densities in Urmia city and level of implementation of detailed plan in the field of building density. in this regard , at first , the status of different urban densities in different periods and the degree of fulfillment of a detailed plan was analyzed and Then, with the introduction of effective indicators on determination of real building density, city land capacity was determined and modeled with the Multi-Criteria Evaluation and in GIS software . the density indicators in the city are distributed as unbalanced in the urban regions And 78% of the building densities predicted by the detailed plan were not realized . the result of modeling the capacity of building density Suggests unused to 68 % of the city's land capacity and The distance is far to favorable conditions, especially in regions 2,3 and 5of the city. Comparison of the results of the research model with the existing condition of building density in Urmia Suggests The movement of the density profile From higher than the density in the central and middle regions of the city towards the medium and lower density in the city's margins and Creates a pyramid mode in the city.

The purpose of ‎this study is to analyze the status of urban parks enjoyment and accessibility in Eslamshahr, a city ‎with a population of more than 540000 located in 12 Km southwest from Tehran. The research ‎method is Comprative evaluation and we use descriptive statistics indexes such as per capita and ‎covered land ratio, and accessibility measures based on minimum distance to the nearest park, and ‎the park access areas. Finding showed that both per capita park lands (2.2 m2) and ratio of park ‎lands are low (2.2 m2 and 1.3% respectively). There are also large disparities in spatial distribution ‎of parks as more than 42% of the city's area, in which more than 29.5% of the population reside in, ‎is not within parks access areas. This is while in the southern part of the city, access area of 10 ‎parks are overlapped. In term of accessibility, district 4th of Eslamshahr municipality in south, has a ‎more appropriate condition, so that half of its inhabitants reside in a maximum distance of 60 m ‎from nearest park. In contrast, district 5th has only one park and the distance between most ‎residents and the park is high. In order to move towards environmental justice, it is necessary to ‎allocate more land to parks and construct and develop parks, especially in the central part and in ‎the parts with no access to existing parks.

Quality of life, social capital, and social sustainability are the key pillars of sustainable development which,on one hand,all of them have a deep link with the human and social dimension of development and on the other hand they are closely interrelated. Lack of satisfaction from built environment quality,lack of positive interactions in cities,distrust,unwillingness to participate in the city residents have been overshadowed social capital and, consequently,social sustainability in the cities. This research aims to identify and investigate the impact of the built environment on social capital and social sustainability indicators in the historical neighborhood that linked to the Kerman Bazar. The questionnaire and field study are the main data collection methods. The results show there is a direct and meaningful relationship between the quality of the built environment and social capital and also there is a direct and indirect meaningful relationship with social sustainability through the role of mediating social capital. The results of structural equations modeling also demonstrate that by improving the quality of the built environment, the status of social sustainability and social capital in the Linked neighborhoods of Kerman Bazar will improve. Research results point to the importance of the role of the quality of the built environment on social capital and social sustainability. The most effective criterion on social capital and social sustainability is perceived environments while accessibility to sports activities and cultural space is the least. Moreover, the results indicate aging and residence period are also effective factors in increasing social capital and social sustainability.

According to the rapid global growth in urban population and the concentration of facilities and infrastructure in cities, in the event of an earthquake, the city's vulnerability is very widespread and it would threaten so many lives and properties.Therefore,providing logical solutions and applying passive defense principles can be an effective way to meet citizens at the event of crises. The research has been done on the basis of documentary methods, in Sanandaj.In order to achieve goals of the research, using the library studies, and existing documents, the necessary indicators to determine the vulnerability of urban textures to earthquakes were identified and extracted. In the next step, using the multi-criteria decision-making techniques such as the hierarchical analysis process and using Delphi fuzzy method, the level of importance of the effective indicators on the degree of vulnerability was identified. The purpose of using Delphi method is to reach an agreement between experts in relation to a particular topic, which is done by using a survey of experts on a variety of occasions and with regard to their feedback. The advantages of this method is providing unbiased answers, frequency and statistical analysis of the results of questionnaires. Results show that with the movement to the depths of neighborhoods, magnitude of the vulnerability of the monuments has been increased. The results also show that 26.87% of the buildings had the highest vulnerability, 36.6% had high vulnerability, 23.03% had a moderate vulnerability, 9.69% had low vulnerability and 36.4% Had the least vulnerability.

Among the new movements in the field of urban transportation, aimed at promoting pedestrian staging in the city and reducing vehicle dominance, are pedestrian-oriented and policies of making pedestrian street. However, the implementation of pedestrian streets in different cities has been accompanied by a variety of results; To the point where some pedestrian streets have failed and they have been opened again on the cars. In the present study, the evaluation of the policies used in the southern khayyam pedestrian street of urmia projects is being addressed. In this study, the analysis and evaluation of the strategies and policies used in the southern khayyam pedestrian street and the comparative analogy with the standard components and standards of pedestrian spaces attempts to identify the strengths and weaknesses of the axis and to solve its deficiencies. The research method is descriptive-analytical and based on documentary and field studies. In order to make a better comparison, Friedman's test has been used to rank the criteria and criteria. The results of the study indicate that southern khayyam pedestrian street quality is moderate and in some criteria it is not favorable. paying attention to the needs of the stakeholders, diversifying the design and creation of facilities for attracting different users, flexibility of the plan, decisive handling of unauthorized motorcycles and the like, The use of indigenous patterns with the cultural and historical context is one of the ways in which they can create more vibrant, more relaxing pedestrian walkways.

The uneven growth, along with the spread of horizontal and scattered areas, are among the problems of today's cities. The development of the city's physical form is a process that affects all of the city's structures directly or indirectly. For this reason, if this process does not flow properly, it has many adverse effects on the city. One of the factors influencing the physical development of cities is the political actions of the government. Regarding these cases, the aim of this paper is to investigate and analyze the Urban Sprawl in Qom with an emphasis on the transformations of political divisions. The research methodology is based on the applied purpose and descriptive-analytic nature. The method of collecting library and document information. To investigate the urban dispersion phenomenon and the effect of political dividends on it, the Holdern models, the balanced distribution degree (Shannon Entropy, Gini coefficient), aggregation (moron coefficient, coefficient of Gery), dispersion coefficient, Herfindal concentration index, and population density have been used. Also, ARC GIS software has been used to map the maps. The results showed that after the expansion of the city of Qom to the provincial capital in 1375, while the existence of a dispersed urban phenomenon, the dispersed trend has been intensified so that the results of all models, especially the Holdern model, show this trend well.

Changing the balance of radiation through urbanization and change in Land use has led to an increase in the temperature of cities. The radiation Balance is calculated through the properties of the Net radiation flux (RN) including Albedo (α), long input wavelength (RL ↓), short input (RS), the Long output radiation (RL ↑), and Land Surface temperature (LST) is measured. The research has examined the radiation Balance by using satellite images of Landsat 4-5 and 8 for the years 1998, 2010 and 2017 in August for Mazandaran. The characteristics of Net radiation in various Land use (urban and suburban residential areas, urban green spaces and suburbs) were analyzed by ANOVA and Tukey's post hoc test. The results showed that the amount of radiation flux in the selected applications has a significant difference. The differences are due to changes in the output energy (α and RL ↑), and any build-up and reduction of vegetation in the region will ultimately lead to changes in the radiation pattern and the formation of the new climate. Therefore, part of the process of increasing the temperature of the meteorological stations located within the city, not because of climate change and global warming but also from urban development and change of Land use.