A new multi-level analysis method of introducing the super-element modeling method, derived from the multi-level analysis method first proposed by O. F. Hughes, has been proposed in this paper to solve the problem of ...A new multi-level analysis method of introducing the super-element modeling method, derived from the multi-level analysis method first proposed by O. F. Hughes, has been proposed in this paper to solve the problem of high time cost in adopting a rational-based optimal design method for ship structural design. Furthermore,the method was verified by its effective application in optimization of the mid-ship section of a container ship. A full 3-D FEM model of a ship,suffering static and quasi-static loads, was used as the analyzing object for evaluating the structural performance of the mid-ship module, including static strength and buckling performance. Research results reveal that this new method could substantially reduce the computational cost of the rational-based optimization problem without decreasing its accuracy, which increases the feasibility and economic efficiency of using a rational-based optimal design method in ship structural design.展开更多
A ship＇s crew plays an important role in the maritime transportation sector and their performance is paramont in the shipping industry. On this account, an impartial evaluation of the crew＇s performance is an import...A ship＇s crew plays an important role in the maritime transportation sector and their performance is paramont in the shipping industry. On this account, an impartial evaluation of the crew＇s performance is an important issue. In this paper, the ship officer＇s performance evaluation problem is studied. The performance evaluation criteria that shipping companies take into account are determined and a performance evaluation process is modelled by using the FAHP （Fuzzy Analytic Hierarchy Process） based on Chang＇s Algorithm. Linguistic variables and fuzzy numbers are used in the assessment process. The results of the proposed model demonstrate that the FAHP method is effective and helps managers make better and more reliable decisions under fuzzy circumstances.展开更多
The existence of linear quadratic optimal control of ship automatic steering instruments is studied. Firstly, the sufficient conditions for the quadratic integrability of the solutions of linear second order time-vari...The existence of linear quadratic optimal control of ship automatic steering instruments is studied. Firstly, the sufficient conditions for the quadratic integrability of the solutions of linear second order time-variant differential equations are developed. Secondly, the optimal control form of the ship automatic steering instrument is obtained by using the dynamic programming method, which guarantees a minimal ship sway range, during long-distance navigation, by using as little energy as possible. Finally, based on the above mentioned sufficient conditions, the conditions for the realization of optimal control are obtained, which provides a foundation for choosing the weighted coefficients for optimal control in engineering.展开更多
基金Supported by the Project of Ministry of Education and Finance(No.200512)the Project of the State Key Laboratory of ocean engineering(GKZD010053-10)
文摘A new multi-level analysis method of introducing the super-element modeling method, derived from the multi-level analysis method first proposed by O. F. Hughes, has been proposed in this paper to solve the problem of high time cost in adopting a rational-based optimal design method for ship structural design. Furthermore,the method was verified by its effective application in optimization of the mid-ship section of a container ship. A full 3-D FEM model of a ship,suffering static and quasi-static loads, was used as the analyzing object for evaluating the structural performance of the mid-ship module, including static strength and buckling performance. Research results reveal that this new method could substantially reduce the computational cost of the rational-based optimization problem without decreasing its accuracy, which increases the feasibility and economic efficiency of using a rational-based optimal design method in ship structural design.
文摘A ship＇s crew plays an important role in the maritime transportation sector and their performance is paramont in the shipping industry. On this account, an impartial evaluation of the crew＇s performance is an important issue. In this paper, the ship officer＇s performance evaluation problem is studied. The performance evaluation criteria that shipping companies take into account are determined and a performance evaluation process is modelled by using the FAHP （Fuzzy Analytic Hierarchy Process） based on Chang＇s Algorithm. Linguistic variables and fuzzy numbers are used in the assessment process. The results of the proposed model demonstrate that the FAHP method is effective and helps managers make better and more reliable decisions under fuzzy circumstances.
基金supported by National Nature Science Foundation of P.R.China(No.69974032).
文摘The existence of linear quadratic optimal control of ship automatic steering instruments is studied. Firstly, the sufficient conditions for the quadratic integrability of the solutions of linear second order time-variant differential equations are developed. Secondly, the optimal control form of the ship automatic steering instrument is obtained by using the dynamic programming method, which guarantees a minimal ship sway range, during long-distance navigation, by using as little energy as possible. Finally, based on the above mentioned sufficient conditions, the conditions for the realization of optimal control are obtained, which provides a foundation for choosing the weighted coefficients for optimal control in engineering.
