Application of the fuzzy comprehensive evaluation model based on entropy to the risk evaluation of u

I.
INTRODUCTION
(HEADING 1)
"Entropy" was originally a concept of the thermodynamics proposed by Germany physicist Crowe Sues in the mid-19th century. It suggested that an average level of the heat within the system. In 1948, the information theory founder, Shannon, introduced the information entropy to describe the uncertainty of the signal of signal source for the first time. He used the probabilistic statistical method to give the definition of information entropy of source:
the fuzzy comprehensive evaluation method to combine the evaluating indicator's objective entropy power with the subjective weight of importance to determine the weight. Establish a fuzzy comprehensive evaluation model based on entropy. It will be applied to the safety evaluation of urban gas pipeline system. The factors affecting the safety of urban gas pipeline are analyzed and evaluated systematically. According to the reality in Handan urban gas pipeline, the evaluating indexes are determined. Then this model is used to assess the safety level of gas pipeline in Handan. The results match the reality well after verifying. The presentation of this model is aim to make a more precise safety evaluation for urban gas pipeline and to provide foundation for relevant units to take measures.
of probability. Under the above conditions, the entropy is:
Zhanglin Guo
Lifang Sun
Lilei Bo
Department of civil engineering North China Institute of Science and Technology Beijing, China gg_zz_ll@
School of Economics and Management HeBei University of Engineering Handan, HeBei, China fangfangI98549@
From the 1970s until now, with the process of Reform and Opening up, China's economy has entered a period of rapid growth. Because of the development of many cities, the urban energy structure has had tremendous changes. Coal, oil and gas have undoubtedly become the main theme of optimizing urban energy structure. City Gas has become an important part of urban construction, and the gas supply pipeline of cities is one of the main indicators of urban modernization. Along with the continuous development of city gas customers, the city gas facilities and underground pipe network are growing day by day. The popularity of city gas supply undoubtedly plays a significant role for improving the city's environmental quality, reducing people's domestic labor and improving the quality of residents' life. City gas pipeline project is an important project of the construction of modem cities, while bringing the convenience to the lives of the residents, also has the significant hidden danger for various reasons. Because the characteristics of gas pipeline, security problem has been closely monitored. Researching on the pipeline security and the risk has been developing for 30 years abroad. Our country's pipeline safety evaluation studies started relatively late. As the pipeline status and conditions differ to the foreign countries, we must propose the pipeline safety evaluation method which suits our country actually. The fuzzy comprehensive evaluation model based on entropy combined the entropy theory and the subjective type of assignment of experts to determine the weight of the factor levels to eliminate the impact of 978-1-4244-6947-5/10/$26.00 ©2010 IEEE
B.ห้องสมุดไป่ตู้
Computation Model
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H=-L PilnPi i=1
n
xij is the evaluation value of Xi on Ij Identify xij take Xi to be the evaluation of the measure in the k­ category, which expressed as: flijl ' flij2 , ... , flijp . The flijp satisfies the normalization conditions: 0 � fl ijp � 1 p and L fl ijp = 1 , that is to say, {flijp} has the property i=1
the human factor as much as possible, so that evaluation results are more realistic. This approach applied to the city gas pipeline safety evaluation is aim to make a more precise safety evaluation for urban gas pipeline and to provide foundation for relevant units to take measures. II.
365
After the entropy introduces the information theory, it has been widely used in engineering technology, economic management, decision-making control, etc. the entropy theory henceforth obtains a unprecedented development. According to the entropy theory's thOUght and some evaluating indicator's information entropy is smaller, indicating that the target value and the variation degree are bigger, the information content which provides bigger, and plays the role in the quality synthetic evaluation to be also bigger, namely the target weight is also bigger; otherwise are smaller.