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Application of a fuzzy multi-criteria decision-making model for shipping company performance evaluation 总被引:4,自引:0,他引:4
Combining fuzzy set theory, Analytic Hierarchy Process (AHP) and concept of entropy, a fuzzy Multiple Criteria Decision-Making (MCDM) model for shipping company performance evaluation is proposed. First, the AHP is used to construct subjective weights for all criteria and sub-criteria. Then, linguistic values characterized by triangular fuzzy numbers and trapezoidal fuzzy numbers are used to denote the evaluation values of all alternatives with respect to various subjective and objective criteria. Finally, the aggregation fuzzy assessment of different shipping companies is ranked to determine the best selection. Utilizing this fuzzy MCDM model, the decision-maker's fuzzy assessment and the trade-off between various evaluations criteria can be taken into account in the aggregation process, thus ensuring more effective and accurate decision-making. 相似文献
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Arvin R. Savkoor C. T. Chou 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1999,32(4):345-374
This exploratory study considers applications of active aerodynamic devices for suppressing parasitic motion and for improving the response of vehicles to steering, within the scope of the linear dynamic behaviour. A three DOF linear model is chosen to describe the side slip, yaw and roll motion of a baseline front-wheel steered vehicle. The improvements in performance of the base-line vehicle that are achievable by the application of direct yaw and roll moments are determined when either an open loop control pre-filter or a state feedback control law based on LQR design is applied. Unlike the former control, the state feedback control is unable to make the body side-slip angle vanish. The feedback control performance of each of the two moment actuators has been examined separately and then jointly. The advantages of combining the open loop and feedback dual actuator configurations are demonstrated using the two-degree of freedom control scheme. It is found that the scheme yields a spectacular performance but demands unreasonably large moments from the actuators in the context of available aerodynamic forces. On the other hand, the demand on direct yaw and roll moment of actuators is modest when the actuators are controlled using the LQR feedback only and if the control design is used to track a desired yaw rate trajectory and simultaneously to reduce the parasitic rolling motion. Significant improvements in handling and dynamic stability of a base-line vehicle can be achieved by aerodynamically generated direct yaw and roll actuator moments provided the target control performance is reasonable. The configurations of aerodynamic actuators considered are feasible for improving vehicle handling in cornering on motorways but more work remains to be done to explore alternative aerodynamic configurations that give rise to less side effects and higher lift coefficients. 相似文献
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Overexploitation of reef resources and increasing coastal tourism have severely damaged the health of coral reef ecosystems around Hainan Island, South China. Only some reef sites are protected, and the effectiveness of the marine protected areas (MPA) appears inadequate. Networks of MPAs have been widely proposed as a more effective tool for reef conservation. However, little is known about the overall state of the island's coral reefs, and no guidelines exist for MPA network building in China. In this study, the information currently available on the distribution and condition of Hainan's coral reefs is comprehensively used to assess reef status, and to identify other reef areas prior to protection. An MPA network around the island is proposed in terms of monitoring, legal, and management aspects to improve the conservation effectiveness. This could also serve as a model for developing MPA networks for other coastal areas with respect to coral reef conservation. 相似文献
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The shipbuilding output for Taiwan had been 4th in the world until 1999; however, at that time, it dropped to the 9th. Currently, the world shipbuilding capacity greatly exceeds the demand and this disparity could grow to 40% by 2005. Facing this turning point, the main objective of this study is to re-examine the international competitive position of Taiwan's shipbuilding industry; furthermore, to realize the industries' core competences and attempt to recommend competitive strategies for the future development of Taiwan's shipbuilding industry. The results show that Taiwan's main core competence is production management, mainly through heterogeneous resource analysis. This paper also proposes that for general types of ships, Taiwan's development priority should be to utilize low-cost strategies to occupy the market continuously; as to high value added types of ships, Taiwan's priority should be to utilize differential and focus strategies. Finally, the direction of government policy is suggested. 相似文献
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