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Payam Moradi Young Researchers Club Azad University of Tafresh, Iran Eleventh International Conference on Fuzzy Set Theory and Applications (FSTA 2012) Using of Fuzzy AHP Based Multi Criteria Weighting Scheme for GIS Routine in National Iranian Gas
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Outline INTRODUCTION METHODOLOGY A. Finding Pipeline Routing Criteria B. Selection of Factors Affecting the Route in National Iranian Gas Engineering &development CompanyNational Iranian Gas Engineering &development Company C. Refinement of criteria D. Fuzzy TOPSIS model E. Assigning Weights to the Variables F. The FAHP and methodology G. Finding the Pipeline routing by using weighting RESULTS AND DISCUSSION
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The overall objective in selecting a petroleum pipeline route is choosing the shortest, most direct route is always a goal for capital expenditure reasons, but many important goals exist simultaneously in the route selection project and at times these goals may conflict. Geophysical, environmental, political, social, economic, and regulatory factors interact to define the route possibilities Pipeline alignment is an optimization between several factors such as social issues, environmental issues, and cost of the project and so on. 1- Introduction
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A : Finding Pipeline Routing Criteria Establish the shortest possible route connecting originating, intermediate, and terminal locations; Avoid populated areas for public safety reasons Avoid hilly or rocky terrain; Avoid areas with steep slopes Avoid areas with high land cost Methodology :
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Keep rail, road, river, and canal crossings to the bare minimum; Avoid a route running parallel to high-voltage transmission lines or DC circuits; Use an existing right-of-way, if possible; Avoid other obstacles, such as wells, houses, orchards, lakes, or ponds. Avoid unfavorable soil type Avoid reserved forest areas
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B : Selection of Factors Affecting the Route in National Iranian Gas Engineering & development CompanyNational Iranian Gas Engineering & development Company The first step in a routing process is the selection of the factors affecting the pipeline route. Several spatial and non spatial factors affect the pipeline routing. 1 ) Operability : 2 ) Environmental Issues : 3 ) Economic :
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C : Refinement of criteria TOPSIS method is based on choosing the best alternative, which has the shortest distance from the positive-ideal solution and the longest distance from the negative-ideal solution the concept is rational and comprehensible the computation involved is simple the concept allows objective weights to be incorporated into the similarity process
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where D : Fuzzy TOPSIS model The Fuzzy MCDM can be concisely expressed in matrix format : Xij : is the performance rating of the alternative Ai : respect to the jth criterion Cj and wj : represents the weight of the jth criterion Cj : The normalized Fuzzy decision matrix denoted by R is shown below
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the proposed Fuzzy TOPSIS procedure is then as follows : Step1: Decision matrix is normalized Step2: Weighted normalized decision matrix is formed The weighted Fuzzy normalized decision matrix is shown in
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Step4: The distance of each alternative from PIS and NIS are Calculated : Step5: The closeness coefficient of each alternative is Calculated Step6: By comparing i CC values, the ranking of alternatives are determined. Step3: Positive ideal solution (PIS) and negative ideal solution (NIS) are determined
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E : Assigning Weights to the Variables A weighting system has to be devised for weighing each of the map layers. The weighting system forms the backbone of the methodology.The weighted Layers are all summed up to form the suitability layer
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F : The FAHP and methodology Step 1: The fuzzy synthetic extent value ( Si ) with respect to the criterion is defined in Step 2: The degree of possibility of This expression can be regularly written as given in = ==is defined in
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Step3 : The degree possibility for a convex fuzzy number to be greater than k convex fuzzy numbers can be defined by Assume that is: Then the weight vector is given in
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Step4 : Via normalization, the normalized weight vectors are given in Where W is non-fuzzy numbers StatementTFN Absolute (5/2,3,7/2) Very Strong (2,5/2,3) Fairly Strong (3/2,2,5/2) Week (1,3/2,2) Approximaly Equal (1/2,1,3/2) Equal (1,1,1)
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G : Finding the Pipeline routing by using weighting Necessary steps in GIS include: Data Sources Data Input Acquiring topographic maps of the target Area Acquiring satellite imagery of the area Identification of factors affecting the route. Creating new layers for the analysis
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Data Processing Assigning Weights to the Variables Raster Data Analysis Vector Data Analysis: Processing the data, weighting and Overlay Raster Data Analysis: Suitability layer, Cost distancing and Cost direction
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RESULTS AND DISCUSSION
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