clustering method

Urban sprawl is a key aspect of urban planning, resulting from the uneven physical growth of a city's infrastructure in relation to its population growth. This study aims to investigate the effects of urban sprawl on social dimensions, particularly on the sense of security among residents in various neighborhoods of Yazd city.The research is of an applied nature with a descriptive-analytical methodology. Data collection methods included documentary sources and fieldwork. The statistical population comprised all individuals aged 15 to 65 residing in Yazd city neighborhoods, with a sample size estimated using Cochran's formula. Data analysis involved the TOPSIS model to categorize neighborhoods as dense or dispersed based on population density, average residential plot size, and land use ratios. The K-Means cluster analysis model was utilized to assess the sense of security using indicators of social-behavioral, economic, and physical-environmental security on a five-level Likert scale.Findings indicate variations in the average levels of security components, making it challenging to define a universal standard for dense or dispersed neighborhoods. Cluster analysis revealed three distinct levels of security - high, medium, and low. Economic security was higher in dense clusters, while physical-environmental security was more prominent in dispersed clusters due to new constructions. Social-behavioral security levels were relatively consistent across clusters.

Today, with the increasing tendency of the vehicle to walk to public transport is much reduced from their desire the increase of private cars has increased and environmental pollution; So that the air pollution in many countries of the world, especially major cities in Iran is so important that Forced the government to take seriously the issue and adopt policies and programs for its short and long term; In this way and in a different perspective, it is necessary to think. Including urban planners to design their ideas and their views on this issue has been raised and transit-oriented development approach. This approach in urban planning from the 1970s in USA policymakers and researchers in the field of planning and urban design has been considered. Citizens are encouraged to use public transportation in areas with mixed-use residential, commercial and office near a node or transit stops (bus, subway, etc.) is; that if implemented, this type of planning can bring many benefits, including reduction in transport costs, reduce congestion, sustainability and urban vitality, open shape the development of cities and etc. the cause. In our country, Iran, using public transportation and take advantage of the benefits that have been addressed in the cities, especially big cities. And plans have been implemented in these areas. In Tehran, the large-scale projects such as metro and bus systems were operating Extremist; but the development of such systems requires understanding the effectiveness of various dimensions. The aim of this study is to answer questions about the operation of the bus system Extremist in Tehran to what extent the framework for transit-oriented development approach and its physical properties have been considered. Since then one of habitable transit-oriented development quality objectives in this study is that air pollution is taken into account; Using zoning air pollution in Tehran and its compliance with the requirements of transit-oriented development approach around Extremist bus system to answer the question whether or not there is a connection between the two? The aim of this study in terms of development and in terms of descriptive and analytical methods is applied with an approach that outlines the concepts, first, in order to determine the consistency of fuzzy clustering technique using two physical features compact development and mixed land lines were combined. Then, to evaluate the viability of the relationship between quality objectives in this study, air pollution is taken into account; Using fuzzy clustering and interpolation air pollution zoning maps were drawn and transit-oriented development approach around the map requirements Extremist matched to the bus system. Result and Discussion: The results showed that the adaptability transit-oriented development approach in different lines. In the mixing land uses, except in areas north and northeast and southeast of Tehran which has a greater extent than mixing appropriate user In other areas, especially the East, South East and South West between space stations were smaller and the mixing member further includes a separate applications that are enclosed within residential applications, The composition and distribution of inappropriate land use in a way that leads to internalization of trips in the area of development is not development And thus creates demand for travel and the subsequent parking and traffic. The population density is only half the northern, northeastern, southern and western edge is a good population density; This is due to the following areas of immediate gate stations where passengers can easily have access to transportation lines; The most convenient connections between people that can require people with better access to the use of public transport And reduces the desire to travel is by car. In the final map that mixing two layers of integrated land use and population density as is obvious from the north to the south in moving from compliance rate is reduced and areas 10, 12, 13, 14, 15, 16, 20 the index population density and mixed use transit-oriented development approach are the least conformity with the requirements. In the second part after the zoning map pollution in Tehran for six key pollutants over the past 5 years; the results were that In terms of air quality zones 10, 11, 12, 13, 14, 15, 16, 20 critical situations. After comparing pollution hazard map with the map compliance requirements transit-oriented approach can be seen areas at the very least was available in terms of adaptation to unfavorable air quality. Due to the nature of public transit-based development and positive principles that fans of this type of development that believe that what should be considered in the design of urban systems, urban comprehensive planning in order to create the maximum possible match between urban and land use policy and on the other hand urban transportation systems optimized according to the characteristics of the urban network. Lack of requirements-driven approach to development of transport system of buses Extremist around it has been prevented from achieving the goals of quality and quantity; and in some areas extensively alters the components and parameters of transport system Have a great impact on the amount of pollution produced. Accordingly, different areas of Tehran in terms of transport indicators such as the number of trips generated, the type and amount of passages, per capita lamps, LED density, percent of networks and critical and the supply of parking space and non-homogeneous and therefore have different roles in air pollution are caused by urban transport. It is essential in these plans be given to the nature and requirements of this development pattern and to take advantage of the benefits of this form of development as a successful and effective in reducing traffic congestion and social development of viable cause of action. It is proposed to metropolitan Tehran and other large cities in the hands of these projects and the development of comprehensive plans and detailed Transit-oriented development centers in order to establish successful and effective in reducing traffic congestion and social development of viable cause of action.

Weather circulation patterns play a main role in the occurrence of environmental phenomena especially in middle latitude. Occurrence of dry and wet spells is in relation to synoptical system repetitions and types of weather. In this research first by using of Standard Precipitation Index (SPI)، extensive droughts in the province were identified. Then by using Principal Component Analysis (PCA) and Clustering Analysis (CA)، daily circulation patterns in synoptically scale were realized. In order to classify weather types، daily mean temperature data in 500 hPa and in mean sea level pressure were selected from the NCEP/NCAR reanalysis data with a 2. 5 spatial resolution during the period of 1950-2006. For identifying type of weather، array S and Varimax Circulation، and for classifying daily weather types K-Mean Clustering method were used. All the days were divided into 18 groups، which present the most predominant weather circulation patterns in the study region. Composite maps of mean sea level pressure and 500 hPa were drawn for every weather types. At the end، dry and wet spells were compared with frequency occurrence of circulation patterns، then rainy weather and dry weather types were identified.