HBMOA computational efficiency assessed for a hydropower optimization problem

Author(s):  
Eliza Isabela Tica ◽  
Angela Neagoe ◽  
Sanda-Carmen Georgescu ◽  
Silvia Nastase
2012 ◽  
Vol 614-615 ◽  
pp. 751-760
Author(s):  
Guo You Wang ◽  
Xi Lin Zhang ◽  
Yu Shi ◽  
Yang Liu ◽  
Cheng Min Wang ◽  
...  

The electric power system is a specific example among various networks in nature and human society, in which the network flow models and arithmetic can be applied. The node-voltage-based and branch-current-based hybrid electric power network equations are established in this paper, and the reactive power optimization problem is modeled based on the established network equations. It is respectively solved while the reactive power optimization problem is decomposed as two sub-problems, among which a sub-problem is described by quadric minimum cost flow model and another one is expressed by a linear equations. Thereby, the complexity and dimensions of reactive power optimization problem are distinctly reduced due to the two decomposed sub-problems are easy to solve. It is proved that found optimal solution is closed to global by the computational efficiency analysis. The case study is made at IEEE-30 system and it is indicated that proposed approach could improve the computational efficiency of reactive power optimization problem by comparing with traditional optimal power flow arithmetic.


2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Benliang Zhu ◽  
Xianmin Zhang ◽  
Sergej Fatikow

This paper presents a two-step elastic modeling (TsEM) method for the topology optimization of compliant mechanisms aimed at eliminating de facto hinges. Based on the TsEM method, an alternative formulation is developed and incorporated with the level set method. An efficient algorithm is developed to solve the level set-based optimization problem for improving the computational efficiency. Two widely studied numerical examples are performed to demonstrate the validity of the proposed method. The proposed formulation can prevent hinges from occurring in the resulting mechanisms. Further, the proposed optimization algorithm can yield fewer design iterations and thus it can improve the overall computational efficiency.


Author(s):  
Yong Zhang ◽  
Mingyong Zhao ◽  
Peiqing Ye ◽  
Jiali Jiang ◽  
Hui Zhang

The well-designed feedrate optimization algorithm can obtain higher machining efficiency with various machining related constraints, thus, it is widely considered in the high-speed and high-precision machining. However, the low computational efficiency still limits the application of the optimization method. For the non-linear optimization problem of spline toolpath with feedrate-, actuator velocity-, acceleration- and jerk-limited, a linear approximation is adopted by a pseudo-jerk method and the efficient linear programming method can be applied to solve the optimization problem. To improve computational efficiency further, curvature-base window technique is presented and the whole spline toolpath is split at the curvature extreme points, which are also named critical points in traditional planning method. Thereafter, a novel feedback interpolation is presented based on Steffensen iterative accelerator method to eliminate the feedrate fluctuation caused by nonanalytic relationship of spline parameter and arc-length. Finally, simulations and experiments validations show that the proposed method is able to reduce computational burden and traversal time notably with multi-constraints.


2021 ◽  
Vol 49 (1) ◽  
pp. 72-77
Author(s):  
Alexander Lagerev ◽  
Igor Lagerev

The article develops a procedure for optimizing the technical characteristics of ropeways - the step and the height of intermediate towers, and carrying ropes tension force. The optimization problem was based on the minimization of the tower structures cost. The reduction of computing labor intensity is based on the fact that the position of the minimum point of the objective function will be tied to one of the optimization restrictions. This allowed us to propose two ways to reduce the labor intensity of computing: a) reduction in the dimension of the optimization problem; b) replacement of the search for the minimum of the objective function with the solution of the nonlinear algebraic equation. The article shows that the proposed algorithm has increased computational efficiency. The algorithm allows us to obtain the same optimal values of technical characteristics of ropeways as in the solution of the previously developed optimization task but using simpler mathematical methods.


TAPPI Journal ◽  
2019 ◽  
Vol 18 (10) ◽  
pp. 607-618
Author(s):  
JÉSSICA MOREIRA ◽  
BRUNO LACERDA DE OLIVEIRA CAMPOS ◽  
ESLY FERREIRA DA COSTA JUNIOR ◽  
ANDRÉA OLIVEIRA SOUZA DA COSTA

The multiple effect evaporator (MEE) is an energy intensive step in the kraft pulping process. The exergetic analysis can be useful for locating irreversibilities in the process and pointing out which equipment is less efficient, and it could also be the object of optimization studies. In the present work, each evaporator of a real kraft system has been individually described using mass balance and thermodynamics principles (the first and the second laws). Real data from a kraft MEE were collected from a Brazilian plant and were used for the estimation of heat transfer coefficients in a nonlinear optimization problem, as well as for the validation of the model. An exergetic analysis was made for each effect individually, which resulted in effects 1A and 1B being the least efficient, and therefore having the greatest potential for improvement. A sensibility analysis was also performed, showing that steam temperature and liquor input flow rate are sensible parameters.


2019 ◽  
Vol 2019 (1) ◽  
pp. 62-68
Author(s):  
Michael J. Vrhel ◽  
Artifex Software

Ghostscript has a long history in the open source community and was developed at the same time that page description languages were evolving to the complex specification of PDF today. Color is a key component in this specification and its description and proper implementation is as complex as any other part of the specification. In this document, the color processing and management that takes place in Ghostscript is reviewed with a focus on how its design achieves computational efficiency while providing flexibility for the developer and user.


2020 ◽  
Vol 2020 (14) ◽  
pp. 306-1-306-6
Author(s):  
Florian Schiffers ◽  
Lionel Fiske ◽  
Pablo Ruiz ◽  
Aggelos K. Katsaggelos ◽  
Oliver Cossairt

Imaging through scattering media finds applications in diverse fields from biomedicine to autonomous driving. However, interpreting the resulting images is difficult due to blur caused by the scattering of photons within the medium. Transient information, captured with fast temporal sensors, can be used to significantly improve the quality of images acquired in scattering conditions. Photon scattering, within a highly scattering media, is well modeled by the diffusion approximation of the Radiative Transport Equation (RTE). Its solution is easily derived which can be interpreted as a Spatio-Temporal Point Spread Function (STPSF). In this paper, we first discuss the properties of the ST-PSF and subsequently use this knowledge to simulate transient imaging through highly scattering media. We then propose a framework to invert the forward model, which assumes Poisson noise, to recover a noise-free, unblurred image by solving an optimization problem.


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