Manoochehr Farajzadeh; Ali Azizi; Hossein Soleymani
Volume 22, Issue 87 , November 2013, , Pages 2-13
Abstract
Direct influence of precipitation on human life and the role it plays in the development of different countries have resulted in an increase in using methods and algorithms for estimating precipitation. A few decades ago, traditional methods were used for predicting precipitation. Then, the presentation ...
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Direct influence of precipitation on human life and the role it plays in the development of different countries have resulted in an increase in using methods and algorithms for estimating precipitation. A few decades ago, traditional methods were used for predicting precipitation. Then, the presentation of meteorological satellite revolutionized this field. Considering the high dispersion of weather stations and rain gauges in developing countries like Iran, free access to images taken by sensors like AVHRR and MODIS is an appropriate opportunity to compensate these deficiencies. We can estimate the volume of water vapor ready to be transformed into precipitation using satellite images, water vapor absorption bands and thermal bands in any time, space, and scale. The algorithms used to estimate precipitation in satellite images are classified into three types- infrared, visible, microwave and a combination of the first two types-based on the sensors’ wave length. Methods based on infrared and visible waves have a good spatial and temporal resolution, while microwaves-based methods measure precipitation directly. Yet, these techniques contain many weaknesses, especially in low earth orbits. Combined techniques are used to compensate these weaknesses. Microwave images are not receivable in Iran, thus we cannot take advantage of microwaves and combined methods. As a result, the present article focuses mainly on visible and infrared wave length.
Manuchehr Farajzadeh; Hadi Hakimi
Volume 18, Issue 70 , August 2009, , Pages 54-58
Abstract
The concept of the network evokes the concept of system. A network is a set of points and lines that carries energy and resources. The points are the places at which sources are injected to lines or collected, for example, schools, terminals, reservoirs, and so on. Lines are connections in the network ...
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The concept of the network evokes the concept of system. A network is a set of points and lines that carries energy and resources. The points are the places at which sources are injected to lines or collected, for example, schools, terminals, reservoirs, and so on. Lines are connections in the network that connect the points. The purpose of this paper is to illustrate three major applications of network analysis in urban planning. Through network analysis, the best route, which is generally the closest route between two points, can be achieved to reduce travel costs. Or, it is possible to select the nearest center from among the rescue centers, in order to help the injured in shortest possible time, and to prevent further damage to life and property. Also, through allocation of resources, it is possible to make a more appropriate and rational planning for citizens' access to public services and realization of social justice.
Manuchehr Farajzadeh; Kheder Faraj Kordeh
Volume 17, Issue 65 , May 2008, , Pages 46-51
Abstract
The advancement and development of computer hardware and software technologies has led the GIS to enter a new stage in its evolution. The Mobile Geographic Information System (Mobile GIS) is one of the dimensions of these advancements, which has entered various fields and has been used for various purposes ...
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The advancement and development of computer hardware and software technologies has led the GIS to enter a new stage in its evolution. The Mobile Geographic Information System (Mobile GIS) is one of the dimensions of these advancements, which has entered various fields and has been used for various purposes due to its flexibility, its simplicity compared with traditional GIS systems, requirement of lower level of expertise and the fact of being less costly. Mobile GIS operates within a wider range of GIS technologies, wireless technologies and global positioning system technology. The system has many capabilities in various urban affairs including urban management, and can be utilized in areas such as emergency management, citizen participation, listing and maintenance of property and urban assets, security and public safety in the city and affairs related to customer service spatial issues. This article seeks to explore the applications of this system in various urban management issues while briefly introducing the Mobile GIS and its construction and architecture, as well as the importance of its application in various fields.
