Before there were humans, the world changed only slowly. The climate warmed and cooled, new plants and animals developed and became extinct (绝灭的) in their turn, and sea level rose and fell over periods of thousands...Before there were humans, the world changed only slowly. The climate warmed and cooled, new plants and animals developed and became extinct (绝灭的) in their turn, and sea level rose and fell over periods of thousands, if not millions of years. But during the last two thousand years great changes have taken place. Forests have disap-展开更多
A hydromechanical interface element is proposed for the consideration of the hydraulic-mechanical coupling effect along the interface.The fully coupled governing equations and the relevant finite element formulations ...A hydromechanical interface element is proposed for the consideration of the hydraulic-mechanical coupling effect along the interface.The fully coupled governing equations and the relevant finite element formulations are derived in detail for the interface element.All the involved matrices are of the same form as those of a solid element,which makes the incorporation of the model into a finite element program straightforward.Three examples are then numerically simulated using the interface element.Reasonable results confirm the correctness of the proposed model and motivate its application in hydromechanical contact problems in the future.展开更多
In this work, we study the smoothing effect of Cauchy problem in Sobolev space for the spatially homogeneous Landau equation in the Maxwellian case. We obtain a precise estimate with respect to time variable, which im...In this work, we study the smoothing effect of Cauchy problem in Sobolev space for the spatially homogeneous Landau equation in the Maxwellian case. We obtain a precise estimate with respect to time variable, which implies the ultra-analytic effect of weak solutions.展开更多
With the current development and progress of the socialist marketing economy, the number of the private enterprises in our country increases constantly, and the development scale has been expanded constantly, which ha...With the current development and progress of the socialist marketing economy, the number of the private enterprises in our country increases constantly, and the development scale has been expanded constantly, which has become an important component for China's national economy, and making a huge contribution to promote the increase of China's national economy. In order to occupy a development location among the fierce market competition and expand the market share, the private enterprises in our country make many efforts constantly, such as strengthening and promotion of the internal management concept and the management mode, etc., which really obtains an obvious achievement and progress, however, due to the restriction of the various reasons, there are still many realistic problems existing in the financial cost management for the private enterprises, which restricts the sustainable, modern and scientific development step greatly, for the method on improving the financial cost management level in China's private enterprises and the guarantee of the pertinence and the efficiency for the financial cost management measures to be implemented in the private enterprises, it becomes the key problems which needs to be solved by the private enterprises currently.展开更多
The multiple knapsack problem (MKP) forms a base for resolving many real-life problems. This has also been considered with multiple objectives in genetic algorithms (GAs) for proving its efficiency. GAs use self- ...The multiple knapsack problem (MKP) forms a base for resolving many real-life problems. This has also been considered with multiple objectives in genetic algorithms (GAs) for proving its efficiency. GAs use self- adaptability to effectively solve complex problems with constraints, but in certain cases, self-adaptability fails by converging toward an infeasible region. This pitfall can be resolved by using different existing repairing techniques; however, this cannot assure convergence toward attaining the optimal solution. To overcome this issue, gene position-based suppression (GPS) has been modeled and embedded as a new phase in a classical GA. This phase works on the genes of a newly generated individual after the recombination phase to retain the solution vector within its feasible region and to im- prove the solution vector to attain the optimal solution. Genes holding the highest expressibility are reserved into a subset, as the best genes identified from the current individuals by re- placing the weaker genes from the subset. This subset is used by the next generated individual to improve the solution vec- tor and to retain the best genes of the individuals. Each gene's positional point and its genotype exposure for each region in an environment are used to fit the best unique genes. Further, suppression of expression in conflicting gene's relies on the requirement toward the level of exposure in the environment or in eliminating the duplicate genes from the environment.The MKP benchmark instances from the OR-library are taken for the experiment to test the new model. The outcome por- trays that GPS in a classical GA is superior in most of the cases compared to the other existing repairing techniques.展开更多
文摘Before there were humans, the world changed only slowly. The climate warmed and cooled, new plants and animals developed and became extinct (绝灭的) in their turn, and sea level rose and fell over periods of thousands, if not millions of years. But during the last two thousand years great changes have taken place. Forests have disap-
基金supported by the Innovation Plan for Postgraduate Students sponsored by the Education Department of Jiangsu Province,China (CX08B 107Z)
文摘A hydromechanical interface element is proposed for the consideration of the hydraulic-mechanical coupling effect along the interface.The fully coupled governing equations and the relevant finite element formulations are derived in detail for the interface element.All the involved matrices are of the same form as those of a solid element,which makes the incorporation of the model into a finite element program straightforward.Three examples are then numerically simulated using the interface element.Reasonable results confirm the correctness of the proposed model and motivate its application in hydromechanical contact problems in the future.
文摘In this work, we study the smoothing effect of Cauchy problem in Sobolev space for the spatially homogeneous Landau equation in the Maxwellian case. We obtain a precise estimate with respect to time variable, which implies the ultra-analytic effect of weak solutions.
文摘With the current development and progress of the socialist marketing economy, the number of the private enterprises in our country increases constantly, and the development scale has been expanded constantly, which has become an important component for China's national economy, and making a huge contribution to promote the increase of China's national economy. In order to occupy a development location among the fierce market competition and expand the market share, the private enterprises in our country make many efforts constantly, such as strengthening and promotion of the internal management concept and the management mode, etc., which really obtains an obvious achievement and progress, however, due to the restriction of the various reasons, there are still many realistic problems existing in the financial cost management for the private enterprises, which restricts the sustainable, modern and scientific development step greatly, for the method on improving the financial cost management level in China's private enterprises and the guarantee of the pertinence and the efficiency for the financial cost management measures to be implemented in the private enterprises, it becomes the key problems which needs to be solved by the private enterprises currently.
文摘The multiple knapsack problem (MKP) forms a base for resolving many real-life problems. This has also been considered with multiple objectives in genetic algorithms (GAs) for proving its efficiency. GAs use self- adaptability to effectively solve complex problems with constraints, but in certain cases, self-adaptability fails by converging toward an infeasible region. This pitfall can be resolved by using different existing repairing techniques; however, this cannot assure convergence toward attaining the optimal solution. To overcome this issue, gene position-based suppression (GPS) has been modeled and embedded as a new phase in a classical GA. This phase works on the genes of a newly generated individual after the recombination phase to retain the solution vector within its feasible region and to im- prove the solution vector to attain the optimal solution. Genes holding the highest expressibility are reserved into a subset, as the best genes identified from the current individuals by re- placing the weaker genes from the subset. This subset is used by the next generated individual to improve the solution vec- tor and to retain the best genes of the individuals. Each gene's positional point and its genotype exposure for each region in an environment are used to fit the best unique genes. Further, suppression of expression in conflicting gene's relies on the requirement toward the level of exposure in the environment or in eliminating the duplicate genes from the environment.The MKP benchmark instances from the OR-library are taken for the experiment to test the new model. The outcome por- trays that GPS in a classical GA is superior in most of the cases compared to the other existing repairing techniques.