جستجوی مقالات مرتبط با کلیدواژه « informal settlements » در نشریات گروه « محیط زیست »

The climate becomes warmer than ever before, as evidenced by numerous observations and modeling that has in turn created a warming climate in cities. Therefore, various climate change projects and attention to heatwaves in recent centuries have been considered and the increase in population and its activities in various fields have caused problems such as heatwaves around the world. In addition, changing the pattern of occurrence of these changes and their unpredictability has led to an increase in the number of them in cities and to reduce concerns and adapt to these risks in various aspects of urban life, especially human health, to create sustainable urban forms. This phenomenon has caused the death of thousands of people in the world, and one of the important reasons for this is the flaw of the cities to deal with the increase in heatwaves. While different changes and global warming can affect urban areas, urban areas can also exacerbate these changes. Rising urbanization rates and people's desire to live in cities have led to higher urban temperatures than their surroundings. Studies show that a city with a population of one million people has experienced an increase in temperature between 1 and 12 degrees. This increase in temperature is due to the structure of cities, which has many negative effects and consequences for cities, so urban environments should be planned and designed in such a way as to improve the health of individuals and thus the presence in public spaces of cities. Urban forms such as urban canyons and vegetation at the pedestrian level are among the factors affecting the reduction of urban temperatures in urban areas and neighborhoods, the impact of these factors on the outdoor thermal comfort of humans by few research in Iran has been considered. A review of the research background of the subject shows that no serious attention has been paid to the native urban forms of Iran as a factor for reducing urban heat and promoting human health; However, local urban planning helps architects and planners to address urban problems by identifying needs in indoor and outdoor environments to provide the most effective way to reduce the severity of outdoor environments using all design elements. Given that there is still, no place to pay attention to how urban forms change in order to reduce the effects of climate change and outdoor thermal comfort professionally, so the present study focuses on the impact of urban forms on informal settlements and old textures on outdoor thermal comfort. The ambient air temperature and the creation of outdoor thermal comfort in the city of Mashhad, which is one of the cities that experience the most urban forms of informal settlements. The present article, firstly, examines the research done in the thematic field of the article and then in the next part, the theoretical framework is extracted by using articles, dissertations, and books. In the third part of this framework, using simulation in Envi-met software and PET index output in Rayman software and analysis in Leonardo to identify the effects of urban forms on air the temperature in microclimate and outdoor thermal comfort using physiological equivalent temperature index (PET). Studies conducted in the summer and on August 26, 2019, have been selected due to the high heat of the sun and its effect on creating outdoor thermal comfort in open urban spaces.

Due to the nature of the subject, the research method is applied and based on two parts. In the first part, the documentary method is used to formulate the theoretical framework. Thus, by referring to articles, treatises, and books by taking notes, the information needed to understand the thematic literature as well as studies conducted in the field of research has been collected and then using descriptive and analytical methods to prepare and compile the conceptual framework of research. In the next part of the research, the case study was studied and the maps were extracted using GIS. The method of survey and harvesting of climatic information from the Mashhad Climate Organization has been used to collect climatic data. In order to identify the effects of the influential components of the urban form, the Envi-met 4 and Leonardo software collections as well as Rayman have been used. In this study, most simulations were performed in summer (August) and based on data from Mashhad Meteorological Station. This simulation was selected on August 17, 2019, and at sunrise and sunset between 6:00 AM and 8:00 PM local time due to the high temperature of the sun and its effect on ambient temperature and surfaces in open urban spaces. This simulation lasted for 156 hours for three urban forms.

The present study investigates the outdoor thermal comfort in informal settlements in Mashhad. Various studies have shown that lowering the ambient temperature in summer can reduce environmental thermal stress and thus improve outdoor thermal comfort. The results in this paper suggest that as the height-to-width (H / W) ratio increases, the sun's access to the environment decreases, and the amount of shading on the surfaces increases resulting in a decrease in ambient temperature. Therefore, it can be said that the height-to-width (H / W) ratio is inversely related to the ambient temperature, and urban form factors such as the height-to-width ratio (H / W) and its shading play an important role in reducing the ambient temperature. On the other hand, the simulations performed to show the temperature difference, so that the difference between the mean indexes (PET) during the hours of thermal stress are 0.68 ° C, 2.53 ° C and 3.27 ° C. The heat stress of the Hojjat fabric is greater than that of the other two fabric and there are more hours in the absence of outdoor thermal comfort, which indicates the temperature difference in all three fabric; but the same the difference stems from different environmental parameters in the three urban forms. One of these parameters is the coverage of outdoor surfaces and materials used in the outer shell of buildings, which is indicated by the Tmrt average temperature index as an important parameter in creating thermal equilibrium in the environment. Studies show that the average temperature index of radiant temperature (Tmrt) is directly related to the PET index and the higher the average temperature index of radiant temperature, the higher the PET index, and vice versa, therefore, the high average radiant temperature in the texture of Hojjat compared to the texture of the agent and the Ghale of the building in the peak hours of heat shows the high rate of heat reflection to the environment in the texture of Hojjat compared to the other two textures. Higher average radiant temperature (Tmrt) in the texture of Hojjat means reflecting more heat than urban levels and can be closely related to the materials used in this texture and the amount of sun access and thus the effect of height to width ratio (H / W) on the ambient temperature. And have levels. Due to the color and texture of the brick, it absorbs less heat and gradually releases the hidden heat and its heat exchange with the environment during the night hours when the air cools down. On the other hand, the temperature a difference of 0.68 C in the first and last hours of simulation in the operating tissue shows that the use of brick materials can reduce the heat exchange with the environment and thus reduce the ambient temperature.

IntroductionAttention to the city structure have been influenced since structuralism viewpoint from the early 1960s. At the beginning of the 1960s, Team Ten tried to consider the city like the whole unite, in contrast to the functionalism. In this viewpoint, theorists such as Edmund Bacon, Christopher Alexander and Kevin Lynch have underscored the importance of urban open spaces; streets structure have created most area of them as the most important element of spatial structure that it can enhance connections between space and people. After that at the ending of 1970s, Bill Hillier and Joseph Hinson produced the Space Syntax theory for the cognition of spatial structure and urban configuration. They examined the relationship between space configuration and special behaviors.
The mean of space configuration is the condition of spaces next to each other and makes connection between them. Thus it can be concluded that each change on the arrangement of spaces will create changes in the whole of spatial configuration. In other words, in the city, each change on the city map (add or subtract a space such as streets, open space, etc.) will create changes on the relation of spatial configuration. These changes can vary the probability of activities and events. Recently, it has been proposed to improve the living conditions of residents of informal settlements however, it has not achieved the planned goals. One of the reasons for this problem is inattention to importance of knowing neighborhoods in various aspects of economic, social and physical ones.
This study has tried to survey and analyze the different parameters of spatial configuration for a number of informal settlements of Hamedan through which we can identify the differences between neighborhood structures.
Materials & MethodsThis study has been done using Analytical-Interpretive method, library research, and spatial configuration analysis of several case studies. At the beginning, the literature review was obtained through library research.
The next step, for analyzing the spatial configuration of neighborhood, we produced the map of urban blocks. This map separates full and empty spaces (streets and squares) from each other. After that, linear map is drawn for the city using the software of Depth Map. Then, various parameters of spatial configuration (including Line Length, Integration, Depth, Connectivity, Control and Choice) are extracted by linear map of city. Finally, based on analyzing the various parameters, key strategies are suggested for improving the spatial configuration of case studies.
Discussion and ResultsIn this study, the linear map of Hamedan has been drawn using the software of Depth Map. The linear map is included structure of a series of urban open spaces that they have been created based on the longest view line and connection. After drawing linear map of the city, the parameters of spatial configuration can be extracted for informal settlement. The main parameters of analyzing spatial configuration are included Line Length, General Integration, Local Integration, Depth, Connectivity, Control and Choice that their characteristics for case studies are as follows:Hesar Neighborhood:• The suitable situation in General Integration
• The lowest Local Integration
• The lowest average of Connectivity
• The highest average and standard deviation of Choice
• The suitable situation in Depth
Khezr Neighborhood:• The lowest average of Line Length like the Dizaj neighborhood
• The suitable situation in General Integration
• The highest average of Connectivity
• The lowest average and standard deviation of Choise
Dizaj Neighborhood:• The lowest average of Line Length
• The lowest average of General Integration
• The highest average and standard deviation of Local Integration
• The highest average and standard deviation of Depth
Mazdaghineh Neighborhood:• The lowest average of Line Length
• The suitable situation of Local Integration
• The highest average and standard deviation of Local Integration
• The suitable situation of Depth
• The highest average of Connectivity
• The lowest standard deviation of Control
• The lowest average and standard deviation of Choice
Manouchehri Neighborhood:• The highest average of Line Length
• The highest standard deviation of Line Length
• The highest average of General Integration
• The lowest average of Connectivity
• The highest standard deviation of Control
• The lowest average and standard deviation of Depth
ConclusionAccording to parameters of spatial configuration (Line Length, Integration, Depth, Connectivity, Control, and Choice) in Hamedan and five informal settlements (Hesar, Khezr, Dizaj, Mazdaghineh and Manouchehri), the results showed a significant difference between case studies. However, the situation of spatial configuration of neighborhoods was not satisfactory and it is essential to adjust and organize their spatial configuration parameters.
The following are some general strategies suggested for improving the spatial configuration of case studies:• Hesar Neighborhood: it is essential to create structure of streets and texture for this neighborhood as a whole unit. Therefore these strategies are suggested: “ promoting unity and solidarity in structure of streets and texture”, “developing the available vacant land in the neighborhood” and “creating some main east-west streets to increase Local Integration and decrease the isolation edges of neighborhood”
• Khezr Neighborhood: The dense texture and North-South structure of this neighborhood has caused a lot of pressure on the street in western edge. Therefore, the following strategies are suggested: “decreasing dense and massive texture”, “creating the North-South arterial street in the east of neighborhood for decreasing Depth and isolating eastern part of neighborhood” and “strengthening the relationship of neighborhood with ring road in east of neighborhood”
• Dizaj Neighborhood: the structure and inner configuration of this neighborhood is relatively stable and it seems essential to solve the problem of isolation of overall city. Therefore, these strategies are suggested: “decreasing isolation of neighborhood from the whole of city”, “developing the vacant lands between neighborhood and the city” and “promoting the order of street structure inner the neighborhood”
• Mazdaghineh neighborhood: This neighborhood has the suitable opportunity in spatial configuration of city, but internal configuration of that is strongly influenced by the rural pattern. Therefore, these strategies are suggested: “organizing and disciplining the inner streets of neighborhood”, “redesigning and aggregating of small blocks” and “creating several cross streets in structure of neighborhood”
• Manouchehri neighborhood: The spatial configuration of this neighborhood is better than other informal settlements. It can be attributed to raster-like structure and small area. Therefore, these strategies are suggested: “creating a hierarchy of streets by converting some public streets to Semi-public Street” and “decreasing the uniformity of texture through creating a variety of streets and intersections”.

By the rise of new industrial and technological age, modern industries and services developed mainly in large cities and these cities absorbed massive flows of migrants from towns and villages. This trend caused population growth more thanthe existingservice capacities and,thus, the environmental qualitiesof the cities were gradually undermined. Continuing this situation for some decades became the motive for low-incomes and migrants to face with difficulties in meeting their basic needs. This trend that is partially controlled in developed countries by some policies like regional planning aimed to manage the allocation of population and facilities in the region and promote the environmental quality, now is a challenge in the developing countries.
This is specially the case in Iran as a developing country in which considerable migrations to metropolitan areas have resulted in the rise of informal areas with low-income and migrant dwellers. The main problems here are in spatial structure, visual quality and provision of basic services and facilities. Hence, it’s quite important to think about development ofthese areas environmentally. These problems along withnegative impacts on the quality of life causeseveral social and cultural disorders. The low quality of housing, not enough access to basic services, the lack of public places and suitable streets are some of the problems which affect the quality of environment in informal areas. In addition, these settlements are differentfromeach other economically, socially, culturally and in many other aspects that requires specific pattern of planning and policy making for each of them. In this way, because of the undeniable costs for dealing with environmental problems, it’s quite required to pay enough attention to determine priorities and the best solution.
In this research, the aim is to extract and determine these priorities based on the dwellers’ approach on the environmental quality. Hesar is one of these informal settlements that despite of some plans for arrangement and development ofthe environmental quality is still one of the low-quality neighborhoods in Hamedan city. Therefore, this research isto signify and determine the priorities fordevelopment ofthis area based on a participatory approach.
Materials and The methodological approach here has beendescriptive-analytic method and the data have also beengathered by reviewing the related documents and empirical studies. The theoretical framework which has been developed by reviewing the relevant documents has also applied as the source todeterminethe research approach and extract the indicators. Then, based on principal component analysis method, the importance of the indicators in development ofthe environmental quality has been recognized forthe neighborhood under study. As the dwellers’ approaches to environmental quality areone of the most important criteria in evaluation of the quality and functionality of these settlements, a questionnaire based on the indicators and in the Likert Scale of 5 alternatives has been designed and filled in by the inhabitants. The data from these 200 questionnaires (the number of questionnaires has been defined based on the Cochran’s Test in the SPSS software) entered in the SPSS environment. Then, use ofexploratory component analysis has resulted in extraction ofmain factors. This served as the intake of the next step in which the multi-variation linear regression method, the relationship between these factors and the environmental quality of the neighborhood has been measured. After all, by combining the importance degree obtained for each of the factors and indicators and withthe average of dissatisfactionineach variable, we have determined the priorities for environmental development of Hesar.
Based on the data derived from the questionnaires, in the SPSS environment we had a matrix with 200 rows (the number of questionnaires) and 27 columns (the number of variables or indicators). In the case study, the result for the variable (indicator) “the traffic of automobile and motorbikes” in the communalities table is fewer than 0.4 and so; this indicator isn’t suitable for the analysis model and removed from the set of indicators. This would enhance the amount of KMO. Thefollowing table shows the tests for analysis ofthe suitability of the indicators (Table 1).
As the outcome of the principal component analysis, 7factors determined the main componentsexplaining the environmental quality of the case. The eigenvalue for all of these componentsare more than “1” and the percentage of variance for the first componentis “13.98”, for the second one is “12.13” and for the third one is “10.81” that the sum of variances for whole indicators is “66.34” percent which is acceptable for the research. Then, by rotating the matrix of factors, these componenthave been named based on the indicators each factor includes as “environmental arrangement”, “basic services”, “environmental security”, “spatial structure”, “welfare amenities”, “adverse land-uses” and “social viability”.
In the next step, it’s required to measure the relationships between these componentsand the environmental quality of the case. The method here is the multi-variable linear regression in which, based on stepwise approach, β is determined for the each factor. The most amount of β was measured for the “basic services”, “environmental arrangement”, “welfare amenities” and “environmental security” that are 0.413, 0.388, 0.357, and 0.339, respectively. Then, by multiplying “Component Score Coefficient”, “Beta” and the “average of dissatisfaction” (for each variable), we could determine the priority of the variables based on their scores. The priority is: “Remedial and Sanitary services”, “Public and recreational spaces”, “Urban furniture”, “Security and safety”, “quality of passages and sidewalk” and “Lightening”.
We presented some suggestions topromotethe environmental quality of Hesar based the priorities recognized in the research.
As promotion ofenvironmental quality requires providing diverse services and facilities by the cooperation between relevant organizations and administrative organs, it seems quite necessaryto determine the priorities for each neighborhood and the tasks of these organs.
Although informal settlements are similar to each other in many economic and social aspects, but the differences in environmental aspect make it necessary toestablish appropriate plans separately for each neighborhood. In fact, using the same policies and regulations for different communities in these areas with divergent problems is one of the main reasons of inefficiency of rehabilitation plans.
Although the government and the municipality are responsible for maintaining and meeting the requirements of the communities, but it should be noted that without responsibility of the inhabitants in maintaining urban furniture, public spaces and so on, the quality of the services provided by the government would be gradually undermined. Therefore, it is essential to make attempts for development ofthe participation of inhabitants in community development, promotion ofthe culture and educating the citizenship principals in parallel with spatial and physical development.
As the inhabitants of these areas are mainly low-income and their houses suffer from low quality, the the facilities and services for these people aremore important in comparison withother inhabitants. Indeed, urban managers should pay more attention to these neighborhoods.
One of the existent opportunities in informal settlements is the low value of the land comparedwith other parts of the city. Thus, it could be suggested touse these lands for locating some of the recreational and service spaces. This would decrease the project costs in addition to support development of these neighborhoods.
One of the main problems in informal settlements -and especially in the case of this project- is “safety and security”. This problem in one hand has been derived from different environmental, cultural and economic factors and onthe other hand, it is one of the effective indicators in environmental quality. Withthis problem, it is essential not only for the community but, it isalso notable because it influence nearby neighborhoods and other urban public spaces.