During radial-axial ring rolling process, cooperative strategy of the radial axial feed is critical for dimensional accuracy and thermo mechanical parameters distribution of the formed ring. In order to improve the co...During radial-axial ring rolling process, cooperative strategy of the radial axial feed is critical for dimensional accuracy and thermo mechanical parameters distribution of the formed ring. In order to improve the comprehensive quality of the ring parts, response surface method （RSM） is employed for the first time to optimize the cooperative feed strategy for radial-axial ring rolling process by combining it with an improved and verified 3D coupled thermo-mechanical finite element model. The feed trajectory is put forward to describe cooperative relationship of the radial- axial feed and three variables are designed based on the feed trajectory. In order to achieve multi- objective optimization, four responses including thermo mechanical parameters distribution and rolling force are proposed. Based on the FEM results, RSM is used to establish a response model to depict the function relationship between the objective response and design variables. Through this approximate model, effects of different variables on ring rolling process are analyzed connect- edly and optimal feed strategy is obtained by resorting to the optimal chart specific to a constraint condition.展开更多
A downlink radio resource allocation algorithm is proposed for orthogonal frequency division multiple access( OFDMA) systems. The resource allocation problem about system throughput and user fairness is formulated bas...A downlink radio resource allocation algorithm is proposed for orthogonal frequency division multiple access( OFDMA) systems. The resource allocation problem about system throughput and user fairness is formulated based on the multi-objective optimization theory. Then the optimality conditions are derived,according to which a joint subcarrier and power allocation algorithm is proposed. The simulation results show that the proposed algorithm can dynamically achieve arbitrary levels of compromise between throughput and fairness by adjusting the weighting coefficient,outperforming some static algorithms. In comparison,the classic maximum rate algorithm( MRA),max-min algorithm and proportional fairness( PF) algorithm can only achieve tradeoff in a certain level and are all special cases of the proposed algorithm.展开更多
This work focuses on the best financial resources allocation to define a wind power plant portfolio, considering a set of feasible sites. To accomplish the problem formulation and solution, the first step was to estab...This work focuses on the best financial resources allocation to define a wind power plant portfolio, considering a set of feasible sites. To accomplish the problem formulation and solution, the first step was to establish a long-term wind series reconstruction methodology for generating scenarios of wind energy, applying it to study five different locations of the Brazilian territory. Secondly, a risk-averse stochastic optimization model was implemented and used to define the optimal wind power plant selection </span><span style="font-family:Verdana;">that</span><span style="font-family:Verdana;"> maximize</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> the portfolio financial results, considering an investment budget constraint. In a sequence, a case study was developed to illustrate a practical situation of applying the methodology to the portfolio selection problem, considering five wind power plant</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> options. </span><span style="font-family:Verdana;">The case</span><span style="font-family:Verdana;"> study was supported by the proposed optimization model, using the scenarios of generation created by the reconstruction methodology. The obtained results show the model performance in terms of defining the best financial resources allocation considering the effect of the complementarity between sites, making it feasible to select the optimal set of wind power plants, characterizing a wind plant optimal portfolio that takes into account the budget constraint. The adopted methodology makes it possible to realize that the diversification of the portfolio depends on the investor risk aversion. Although applied to the Brazilian case, this model can be customized to solve a similar problem worldwide.展开更多
With the continuous development of social economy, the development of enterprises has created more opportunities and challenges. In modern enterprise management, comprehensive budget management is an important means o...With the continuous development of social economy, the development of enterprises has created more opportunities and challenges. In modern enterprise management, comprehensive budget management is an important means of internal control and management objectives. Based on the development goals of the company's strategic plan, it implements the decomposition of the task goals by using the budget through scientific control methods, and at the same time, it rationally allocates resources such as human, financial and material within the enterprise, and realizes the financial management methods of the goals through the specific quantification of distribution, assessment and control. Its core goal is to establish a good control environment within the enterprise, unify and coordinate the operation among various departments, give full play to the maximum effect of internal resources, and help the enterprise achieve its business objectives. Under the background of employment and financial integration, this paper discusses the optimization strategy of enterprise comprehensive budget management.展开更多
A simple CFD tool, coupled to a discrete surface representation and a gradient based optimization procedure, is applied to the design of optimal hull forms and optimal arrangement of hulls for a wave cancellation ...A simple CFD tool, coupled to a discrete surface representation and a gradient based optimization procedure, is applied to the design of optimal hull forms and optimal arrangement of hulls for a wave cancellation multihull ship. The CFD tool, which is used to estimate the wave drag, is based on the zeroth order slender ship approximation. The hu ll surface is represented by a triangulation, and almost every grid point on the surface can be used as a design variable. A smooth surface is obtained via a si mplified pseudo shell problem. The optimal design process consists of two steps . The optimal center and outer hull forms are determined independently in the fi rst step, where each hull forms are determined independently in the first step, where each hull keeps the same displacement as the original design while the wav e drag is minimized. The optimal outer hull arrangement is determined in the se cond step for the optimal center and outer hull forms obtained in the first step . Results indicate that the new design can achieve a large wave drag reduction i n comparison to the original design configuration.展开更多
Cogeneration units which produce both heat and electric power are found in many process industries. These industries also consume heat directly in addition to electricity. The cogeneration units operate only within a ...Cogeneration units which produce both heat and electric power are found in many process industries. These industries also consume heat directly in addition to electricity. The cogeneration units operate only within a feasible zone. Each point within the feasible zone consists of a specific value of heat and electric power. These units are used along with other units which produce either heat or power exclusively. Hence the economic dispatch problem for these plants optimizing the fuel cost is quite complex and several classical and meta-heuristic algo- rithms have been proposed earlier. This paper applies the invasive weed optimization algorithm which is inspired by the ecological process of weed colonization and distribu- tion. The results obtained have been compared with those obtained by other methods earlier and showed a marked improvement over earlier ones.展开更多
基金Specialized Research Fund for the Doctoral Program of Higher Education(No.20126102120022) of ChinaNorthwestern Polytechnical University(NPU) Foundation for Fundamental Research(NPU-FFR-JC200822) of China for the support given to the research
文摘During radial-axial ring rolling process, cooperative strategy of the radial axial feed is critical for dimensional accuracy and thermo mechanical parameters distribution of the formed ring. In order to improve the comprehensive quality of the ring parts, response surface method （RSM） is employed for the first time to optimize the cooperative feed strategy for radial-axial ring rolling process by combining it with an improved and verified 3D coupled thermo-mechanical finite element model. The feed trajectory is put forward to describe cooperative relationship of the radial- axial feed and three variables are designed based on the feed trajectory. In order to achieve multi- objective optimization, four responses including thermo mechanical parameters distribution and rolling force are proposed. Based on the FEM results, RSM is used to establish a response model to depict the function relationship between the objective response and design variables. Through this approximate model, effects of different variables on ring rolling process are analyzed connect- edly and optimal feed strategy is obtained by resorting to the optimal chart specific to a constraint condition.
文摘A downlink radio resource allocation algorithm is proposed for orthogonal frequency division multiple access( OFDMA) systems. The resource allocation problem about system throughput and user fairness is formulated based on the multi-objective optimization theory. Then the optimality conditions are derived,according to which a joint subcarrier and power allocation algorithm is proposed. The simulation results show that the proposed algorithm can dynamically achieve arbitrary levels of compromise between throughput and fairness by adjusting the weighting coefficient,outperforming some static algorithms. In comparison,the classic maximum rate algorithm( MRA),max-min algorithm and proportional fairness( PF) algorithm can only achieve tradeoff in a certain level and are all special cases of the proposed algorithm.
文摘This work focuses on the best financial resources allocation to define a wind power plant portfolio, considering a set of feasible sites. To accomplish the problem formulation and solution, the first step was to establish a long-term wind series reconstruction methodology for generating scenarios of wind energy, applying it to study five different locations of the Brazilian territory. Secondly, a risk-averse stochastic optimization model was implemented and used to define the optimal wind power plant selection </span><span style="font-family:Verdana;">that</span><span style="font-family:Verdana;"> maximize</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> the portfolio financial results, considering an investment budget constraint. In a sequence, a case study was developed to illustrate a practical situation of applying the methodology to the portfolio selection problem, considering five wind power plant</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> options. </span><span style="font-family:Verdana;">The case</span><span style="font-family:Verdana;"> study was supported by the proposed optimization model, using the scenarios of generation created by the reconstruction methodology. The obtained results show the model performance in terms of defining the best financial resources allocation considering the effect of the complementarity between sites, making it feasible to select the optimal set of wind power plants, characterizing a wind plant optimal portfolio that takes into account the budget constraint. The adopted methodology makes it possible to realize that the diversification of the portfolio depends on the investor risk aversion. Although applied to the Brazilian case, this model can be customized to solve a similar problem worldwide.
文摘With the continuous development of social economy, the development of enterprises has created more opportunities and challenges. In modern enterprise management, comprehensive budget management is an important means of internal control and management objectives. Based on the development goals of the company's strategic plan, it implements the decomposition of the task goals by using the budget through scientific control methods, and at the same time, it rationally allocates resources such as human, financial and material within the enterprise, and realizes the financial management methods of the goals through the specific quantification of distribution, assessment and control. Its core goal is to establish a good control environment within the enterprise, unify and coordinate the operation among various departments, give full play to the maximum effect of internal resources, and help the enterprise achieve its business objectives. Under the background of employment and financial integration, this paper discusses the optimization strategy of enterprise comprehensive budget management.
基金This work was partially funded by AFOSR (Dr. Leonidas Sakell technical monitor) by NRL (Dr. William Sandberg technical monit
文摘A simple CFD tool, coupled to a discrete surface representation and a gradient based optimization procedure, is applied to the design of optimal hull forms and optimal arrangement of hulls for a wave cancellation multihull ship. The CFD tool, which is used to estimate the wave drag, is based on the zeroth order slender ship approximation. The hu ll surface is represented by a triangulation, and almost every grid point on the surface can be used as a design variable. A smooth surface is obtained via a si mplified pseudo shell problem. The optimal design process consists of two steps . The optimal center and outer hull forms are determined independently in the fi rst step, where each hull forms are determined independently in the first step, where each hull keeps the same displacement as the original design while the wav e drag is minimized. The optimal outer hull arrangement is determined in the se cond step for the optimal center and outer hull forms obtained in the first step . Results indicate that the new design can achieve a large wave drag reduction i n comparison to the original design configuration.
文摘Cogeneration units which produce both heat and electric power are found in many process industries. These industries also consume heat directly in addition to electricity. The cogeneration units operate only within a feasible zone. Each point within the feasible zone consists of a specific value of heat and electric power. These units are used along with other units which produce either heat or power exclusively. Hence the economic dispatch problem for these plants optimizing the fuel cost is quite complex and several classical and meta-heuristic algo- rithms have been proposed earlier. This paper applies the invasive weed optimization algorithm which is inspired by the ecological process of weed colonization and distribu- tion. The results obtained have been compared with those obtained by other methods earlier and showed a marked improvement over earlier ones.
