بررسی پایداری محله های شهری (مطالعه موردی: منطقه 19 شهرداری تهران)

Introduction
History of neighborhood and live in these neighborhoods is approximately as old as citizenship in Iran. Urban neighborhoods can be considered as the smallest unit of social, ethnical and skeletal body of Iranian old cities. Sustainable neighborhood has particular identities of itself, it makes its residents happy, it gives the sense of belonging to them, they also enjoy from the high standards of living and environment, and provide suitable services and accessibilities. Sustainable neighborhood must be planned in a way that besides of efficient exploiting from sources, it also provides rights to choose and enjoy from environment to its residents, an approach which lead the process of neighborhood planning to this way is developing sustainable neighborhood. Today, for finding a solution to the issue of urbanism, approach of developing neighborhood community, with the emphasis to the sustainability of cities with the view centered on neighborhood have got a significant stance. In recent decades, editors and city planners have seen the basis of city development on urban units, i.e. neighborhoods and neighborhoods communities. Planning on the scale of city, no matter of urban life aspects, and with the attention to empirical aspects, have ignored various issues and these are the origin of new ones.    
Because of the dynamicity of urban life, planners' system must be process-based to regard for permanent connection with environment, have a more precise understanding of abovementioned issues. Holistic view require visible scales and be measurable in urban life. Therefore urban planning has put its focus of activities on the neighborhood. For attaining to the sustainable cities, firstly we need sustainable neighborhoods, because neighborhoods are known as the smallest unit of city division. 19^th district of Tehran is faced with enormous problems, some of these issues are as following: rise in immigration and need to expand structure together with weakness in plans and management of forming tissues and urban neighborhoods, not paying attention to create public facilities relative to housing expansion and population, low welfare, framework, social, economical, environmental issues and lack of a comprehensive plan for sustainable development.
Therefore, this study tries by considering to the abovementioned issues and specific problems of 19^th district, focus its attention to the sustainability of neighborhoods.
The main purpose of present study is investigating the sustainability of neighborhoods in 19^th district of Tehran.
 According to the purpose, the main question proposed here is: Are there any differences in 19^th district according to sustainability? And following it, this hypothesis is proposed and it seems that there are meaningfulness differences among neighborhoods in district 19^th.
Method of research
   Considering to the factors and nature of research, method for doing this research is descriptive- analytic. Coefficients under the study in this research, are neighborhood development. Information required for this study is gathered by library (books, statistics and map) and field research (questionnaire, observation and interview). In this research, by using Shannon entropy statistical model, Delphi'a technique and TOPSIS( by formulating in MATLAB software) and other statistical tests, 13-fold neighborhoods of 19^th district of Tehran were investigated with focus on  sustainability. Statistical population is 13 neighborhoods of 19^th district. Sampling method in this study is cluster-based. For choosing elements of each selected cluster, we used random sampling. Because 19^th district have 13 neighborhood, therefore several blocks were selected randomly. Total size of sample according to formula of Cochran is 384 people. Also size of each neighborhood was determined by Cochran formula. Then by designing a questionnaire about neighborhood sustainability and distributing it among residents, sustainability of each neighborhood was detected. For legitimacy of instrument, we used Chronbach's test.
Results and discussion
Due to the ranking of neighborhoods by TOPSIS, studied neighborhoods on the view of sustainability were categorized as good, middle and weak. According to the overall average (sustainability), 54/0 percent of examined neighborhoods were weak, 15/0 were middle, and 31/0 were good. Before ranking of neighborhoods according to their sustainability status, by using TOPSIS technique, we found that among four main coefficients, environmental and economical coefficient on the basis of ci amount had good status, structural had middle status and social coefficients were weak.
Also for identifying the status of coefficient of sustainability in neighborhoods under study better, we used T-TEST test. According to the obtained results, all of coefficients that were used for measuring the sustainability of neighborhoods were meaningful, but in terms of average we observed differences among coefficients. In other words, we observed that in terms of sustainability status, there are meaningful differences among under study neighborhoods. Therefore it cannot be said that all of under study neighborhoods are in a desirable state in terms of sustainability. On the other hand, in terms of Spectral range, coefficients among 1 to 5, based on Likert's is fluctuating, social coefficient with the average of 33/9167 had the highest average and economical coefficients with 10/9219 had the lowest average. Also, in the view of average differences, social, economical and structural coefficients were lower than middle averages and this issue indicates that respondents evaluated these coefficients negative. Also this test showed that sustainable coefficient, besides of being meaningful -5/347 is lower than the middle of average and this indicates that sustainability of being studied neighborhoods is lower than middle average and as a result in terms of sustainability, these neighborhoods are not in a good condition.
Conclusion
In present study, sustainable coefficients in 13neighborhoods of 19^th district have been measured. Besides, for prioritizing the sustainability of neighborhoods, we used professors' comments and urban planning experts. Also for hypothesis test of the study, besides of TOPSIS we used others statistical methods, and this made our study different from others. In general, obtained results by considering to TOPSIS indicates that only 31 percent of neighborhoods have good sustainability status. Findings show that weight of some of sustainability coefficients used in this study declined vastly and sustainability decreased lower than average. This indicates that respondents evaluated these coefficients to be negative in their neighborhoods. In other words, for choosing the options of very low, low, middle, more and much more for every coefficient items, they tended to select low and very low, While average of environment coefficient is more than middle and they evaluated it positive. According to this test, sustainable variable besides of being meaningful with -5/347, is lower than average and this indicates that sustainability in under studied neighborhoods is lower than average and as a result in terms of sustainability, under studied neighborhoods are not in a good condition.