عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Finding the shortest path is the most fundamental parameter in routing the train trajectory this relies on this fact that by shortening the path, the number of the required equipment including tower, fittings and foundation on one hand and the cost of executive operations including topography, geology and soil mechanics and installation costs on the other hand keep decreasing. Yet, various complications along rail transit line as well as the necessity to observe the technical and safety principles oblige use to select longer paths, consequently the path length increases. Therefore, we are convinced to find an optimal route adapted with technical and economic conditions and the least damage and deformation at the environment and a path as short as possible. geographic information system (GIS), as a technology with systematic and in-depth attitude, can be provided as a strong means for routing.to date, a variety of methods have been proposed for designing and routing rapid transit network by various researchers. Decesare' PhD thesis in 1970 is one of the earliest studies conducted in the context of routing rapid transit lines. Decesare propopsed the problem as finding a route with the lowest cost between origin and destination and modelled it. Bruno et al.(2002)have conducted a study in which they aimed to maximize the population covered by the path. Laporte et al.(2005) engaged in resolving the routing problem via heuristic method in 2005.
Afandi zade & Hashemi(2010) resolved the problem of designing a subway network via a heuristic method based on genetic algorithm. In 2004, Parasto Saheb al zamani obtained the best varient by selecting the optimal path in the railway lines via GIS through describing various variants and comparing them in sake of costs of maintenance and the return on capital. Ahad Sotoudeh(2007) examined use of enviornmental principles in routing railway via GIS and selected the best path by considering the parameters such as slope, geological features, rivers and the associated factors, and finally knew use of the Geographic Information System effective in routing railway compared to the rest of traditional methods. Mario et al.(2012) examined designing of rapid railway via GIS and multi-criterion analysis and analyzed three models including heuristic, conservative and hazardous models.
Routing has been considered as the early action in the operations for designing a path, that it must be considered due to its substantial role in how the path subjects to other facilities and enviornment on one hand and a substantial effect that it has in the executive costs of the path on the other hand. Yazd-Ardakan is the region under study that over 80% of the economic activities and 50% of the agricultural and livestock activities are accomplished in this plain. The present research aims to use fuzzy logic method to determine the optimal route of intercity train (Yazd-Ardakan) considering the environmental aspects and factors affecting determination of optimal route. In this method, using operators Gama and Sum, an attempt was made to determine optimal route of intercity train (Yazd-Ardakan).
Hence, to determine the suitable routes to raise the optimal route of intercity train (Yazd-Ardakan), there are a variety of confounding variables with different roles.
Digital layers considered in this research include existing communication network layer, land coverage, gas pipeline, residential and industrial areas, that each of layers were classified followed by the early proccessing, and then mutiplied by the considered weights using analytic hierarchy process (AHP) âconsequently an attempt was made to produce overlap fuzzy maps using fuzzy overlay method and operators 'Sum' and 'Gama'. Thereafter, map 'cost' was produced to expand extracting the differences and proximity functionsâconsequently an attempt was made to extract the optimal path using shoretest path method.
Among fuzzy operators, using operator 'Sum' has extracted a better path than operator 'Gama'. Ultimately, using this method, two paths were extractted. The No. 1 path which has been resulted out of using operator 'sum' enjoys further scores than No.2 path which has been extracted using operator 'Gama'. Length of No. 1 path equals to 58547 meter, in which the proposed rail line which passes through the residential area from the distance of 24228 meter also passes through the residential area in Yazd and Shahedieh city from the distance of 6584 meter. The highest length of path passes through residential, farm and arid areas and shrubbery. Length of No. 2 path equals to 62080 meter, in which 8677 meter out of 28552 meter distance passing through the residential area in No.2 path relates to the area in Yazd and Shahedieh. The highest length of path passes through residential, farm and arid areas and shrubbery, and also 555 meter of this path passes through industrial regions.