Constrained optimization for microbial fermentation was studied. For optimization, we used not the maximum principle but a nonlinear programmingmethod because of the need to consider many metabolic reactions. In the ...
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Constrained optimization for microbial fermentation was studied. For optimization, we used not the maximum principle but a nonlinear programmingmethod because of the need to consider many metabolic reactions. In the case of L-lysine fermentation, the optimization problem in L-lysine production was formulated as a nonlinear programming problem. In general, the state equations based on material balances are represented as differential equations, but such equations which are dependent on time can not be applied to a nonlinear programming problem. Therefore, the state equations were made discrete in a time base, and a new single vector which is not dependent on time was substituted. From these formulae, the objective function and the constraints using nonlinear programming problem were defined as the amount of L-lysine produced, and as a metabolic reaction model and empirical equations, respectively. Computer program was developed to solve this constrained nonlinear programming problem. The applied algorithm of the computer programming was a sequential quadratic programmingmethod (SQP method). When the constrained nonlinear programming problem is solved using the SQP method, the maximum amount of L-lysine produced and the optimal feeding rate of L-threonine could be calculated. From the calculated results, it was clear that introduction of the equality and inequality constraints was easy. L-Lysine at a concentration up to 75.3 g/l could be produced when the fermentation was carried out under optimal conditions.
Small-molecule drugs are of significant importance to human health. The use of efficient model-based de novo drug design method is an option worth considering for expediting the discovery of drugs with satisfactory pr...
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Small-molecule drugs are of significant importance to human health. The use of efficient model-based de novo drug design method is an option worth considering for expediting the discovery of drugs with satisfactory properties. In this article, a deep learning model is first developed for identifications of protein-ligand complexes with high binding affinity, where the Mol2vec descriptor, the convolutional neural network, and the gate augmentation-based Attention mechanism are used for the model construction. Then, an optimization-based de novo drug design framework is established by integrating the deep learning model into a Mixed-Integer NonLinear programming (MINLP) model for drug candidate design. The optimal solution of the MINLP model is further verified by the physics-based methods of molecular docking and molecular dynamics simulation. Finally, two case studies involving the design of anticoagulant and antitumor drug candidates are presented to highlight the wide applicability and effectiveness of the MINLP-based de novo drug design framework.
The pose of the moving platform in parallel robots is possible thanks to the strong coupling, but it consequently is very difficult to obtain its forward displacement. Different methods establishing forward displaceme...
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The pose of the moving platform in parallel robots is possible thanks to the strong coupling, but it consequently is very difficult to obtain its forward displacement. Different methods establishing forward displacement can obtain different numbers of variables and different solving speeds with nonlinear equations. The nonlinear equations with nine variables for forward displacement in the general 6-6 type parallel mechanism were created using the rotation transformation matrix R, translation vector P and the constraint conditions of the rod length. Given the problems of there being only one solution and sometimes no convergence when solving nonlinear equations with the Newton method and the quasi-Newton method, the Euler equation for free rotation in a rigid body was applied to a chaotic system by using chaos anti-control and chaotic sequences were produced. Combining the characteristics of the chaotic sequence with the mathematical programming method, a new mathematical programming method was put forward, which was based on chaos anti-control with the aim of solving all real solutions of nonlinear equations for forward displacement in the general 6-6 type parallel mechanism. The numerical example shows that the new method has some positive characteristics such as that it runs in the initial value range, it has fast convergence, it can find all the possible real solutions that be found out and it proves the correctness and validity of this method when compared with other methods.
A branch-and-bound/capacitated transhipment method for determining the optimal layout of a radial low-voltage-distribution network is presented. Branch-and-bound organisation, postoptimisation and list-processing tech...
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A branch-and-bound/capacitated transhipment method for determining the optimal layout of a radial low-voltage-distribution network is presented. Branch-and-bound organisation, postoptimisation and list-processing techniques, used to solve problems of a realistically large size on medium-size computers, are discussed. Case studies and an example are also given.
As a new robot mechanism variable geometry truss Manipulator call be applied widely for its good performance. Forward displacement of variable geometry truss manipulator is always transformed into finding the Solution...
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ISBN:
(纸本)9783642015069
As a new robot mechanism variable geometry truss Manipulator call be applied widely for its good performance. Forward displacement of variable geometry truss manipulator is always transformed into finding the Solutions of nonlinear equations. Newton iterative method is all important technique to one dimensional and multidimensional variable and often used to solve nonlinear equations. Iterative process is sensitive to the initial point. The mathematical programming method is adopted when the iteration diverges with the Newton and quasi-Newton methods. A new method of finding all solutions of nonlinear questions is proposed, in which we combine mathematical programming method with hyper-chaotic neuron network system and utilize hyper-chaotic network system to obtain locate initial points. The numerical example in dodecahedron variable geometry truss manipulator synthesis shows that all solutions have been quickly obtained, and it also shows that the method is correct and effective. This provides a simple and new method for mechanism design.
This paper reviews some advances and applications in mathematical programming method for numerical modeling of elastic-plastic contact problems. Emphases are on the parametric variational principle and quadratic progr...
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ISBN:
(纸本)9781402064043
This paper reviews some advances and applications in mathematical programming method for numerical modeling of elastic-plastic contact problems. Emphases are on the parametric variational principle and quadratic programmingmethod used for analysis of elastic-plastic contact problems with isotropic/orthotropic friction law. The contact problem with friction between two elastic-plastic Cosserat bodies is treated in the same way as that in the conventional plastic analysis. There is no available rule for choosing a reasonable value of the penalty factors for simulation of the contact problems of Cosserat materials, and they are therefore cancelled through a special technique so that the numerical results can be of high accuracy. Two numerical examples are presented to show the efficiency of the model and algorithm presented.
In this paper, we investigate the multiple attribute decision making problems where the decision-making information and attribute weight vector are both given by the interval-valued intuitionistic fuzzy number (IVIFN)...
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ISBN:
(纸本)9781479920723
In this paper, we investigate the multiple attribute decision making problems where the decision-making information and attribute weight vector are both given by the interval-valued intuitionistic fuzzy number (IVIFN). We introduce a mathematical model to obtain the comprehensive value of each alternative by the form of IVIFN. Then we utilize the TOPSIS method to rank all the alternatives. Finally, an illustrative example is used to illustrate applicability of the proposed method.
A mathematical programming method to optimize the distribution field of a truss-like material is presented. The densities and angles of members are optimized in two separate procedures in each iteration. An explicit s...
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A mathematical programming method to optimize the distribution field of a truss-like material is presented. The densities and angles of members are optimized in two separate procedures in each iteration. An explicit sub-problem in a variable separation form is established at every iteration procedure. At each sub-problem, the stress constraint function is expanded into a trigonometric series of the member angles. According to the extreme condition, the optimal orientations of members are determined. The member densities are optimized using the method of moving asymptotes (MMA). Two examples demonstrate that the optimal truss-like structures are very close to analytic solutions.
In this paper, we investigate the multiple attribute decision making problems where the decision-making information and attribute weight vector are both given by the interval-valued intuitionistic fuzzy number (IVIFN)...
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ISBN:
(纸本)9781479920747
In this paper, we investigate the multiple attribute decision making problems where the decision-making information and attribute weight vector are both given by the interval-valued intuitionistic fuzzy number (IVIFN). We introduce a mathematical model to obtain the comprehensive value of each alternative by the form of IVIFN. Then we utilize the TOPSIS method to rank all the alternatives. Finally, an illustrative example is used to illustrate applicability of the proposed method.
Based on elementary group theory, the block pivot methods for solving two-dimensional elastic frictional contact problems are presented in this paper. It is proved that the algorithms converge within a finite number o...
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Based on elementary group theory, the block pivot methods for solving two-dimensional elastic frictional contact problems are presented in this paper. It is proved that the algorithms converge within a finite number of steps when the friction coefficient is ''relative small''. Unlike most mathematical programming methods for contact problems, the block pivot methods permit multiple exchanges of basic and nonbasic variables.
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