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1、A DECISION SUPPORT APPROACH FOR THE EVALUATION OF TRANSPORT INVESTMENT ALTERNATIVESA DECISION SUPPORT APPROACH FOR THE EVALUATION OFTRANSPORT INVESTMENT ALTERNATIVESDr. Nurbanu CaliskanTechnical University of Istanbul, Faculty of Civil Engineering, Dept. of Transportationtel.:+90 212 2853671 fax.:+9
2、0 212 285 3420e-mail:ncaliskanhttp:/ INTRODUCTIONArriving at a conclusion in transport investment needs serious attentiveness and attention, because the transport issue is very complicated. First of all, youll face high costs. These wide-scaled investments have always been carried out causing the st
3、ate budget to bear big shares. However, its not only the financial aspect. Transportation has a dynamic build and has multidimensional effects. The social characteristics of society, urbanisation, environmental conditions, energy supply, political balance; are all major factors to be consideredand t
4、hat affect the solution of transport. In other words, there is a mutual influence. As much as the content and importance increase, these mutual influences enlarge more and more. Thus, while deciding on investments, these dynamic mutual influences must be taken into account as much as the capacity th
5、at will be gained. Its vital to choose the most suitable and useful investment according to the countries conditions and economy, in short, deciding to make the best investment.The decision-making mechanism to invest is generally under control of political office. But this power is emphatically advi
6、sed to consult with scientific bodies. It is obvious that consulting experts and scientists while making a decision on transport investments will be very positive and contemporary.2.THE OUTLINE OF THE NEW APPROACH TO THE DECISION EVALUATION OF TRANSPORT INVESTMENTSA decision supporting criteria or b
7、asis must be established based on scientists and scientific experience and foreseeing, in order to be able to evaluate the transport investment. For this purpose, cognitive maps that reflect a persons thoughts network as a mathematical model have been studied to be one of the modern decision-making
8、methods. Taking the fact that cognitive maps enjoy the property to show hierarchy structure of cause-result relations into consideration, another decision-making method named Analytical Hierarchy Process, has been decided to be supported (Caliskan, 1998).The decision-support method Analytical Hierar
9、chy Process , which has proved that it can be applied to transport problems successfully, that is, it enables the possibility to make data transfer between the decision-making and the model, was thought to take the subjective evaluation of the experts into consideration and to have the capability to
10、 judge all the possible findings and thus contribute to the decision process. So, the model was tried to be established.It is believed that the stage, in which the judgements of experts are determined, which will provide the Analytical Hierarchy Process with data support, will help to put the comple
11、x problems of recent years to a certain form. Besides, the use of the Cognitive Map method, which is an excellent tool for understanding the relationships, will be anappropriate and original approach. So, it was found that experts points of view that are extensive complicated, can be grouped and som
12、e can be eliminated; and thus, that Cognitive Centrality that will form a base Analytical Hierarchy Process can be obtained (Caliskan, 1998).3. COGNITIVE MAPSThe Cognitive Map is a signed digraph including the way individuals, groups, and experts realise and understand a problem as well as the bilat
13、erally connected elements ( Lee et al, 1992). So, the thoughts, values, and tendencies and the relations among them have been modelled to give the opportunity to work on them. The Cognitive Map can present individuals thoughts and their belief systems in a mathematical model. Concepts, thats, decisi
14、on choices, call results, effects and purposes are represented with nodes and the causal relationships are indicated with graded and signed arrows (Hwang and Lin, 1987).There are two kinds of elements as concepts and derived beliefs. Concepts are shown as variables and causal beliefs as the relation
15、s among variables. Concepts can be connected to each other by three types of causal relations. The degree of complication varies in connection with the type of the cognitive map. There are three types of Cognitive Maps: the simple form, graded map estimate map.There are three kinds of expression in
16、the simple form and they are “+”, “-“, “0”. If there is a linear relationship between two concepts, ie. if ones value increases while the others value is increasing, this relationship is expressed with a “+”. If the opposite is valid, the expression is “-“; and if there is no relationship at all, the expression becomes “0”. If the relationships are shown with their weights, this forms the weig
