In order to achieve solid-liquid separation and recycling of drilling fluid during petroleum drilling, a new type of solid-liquid separation device was designed and developed to achieve high-efficiency solid-liquid se...
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In order to achieve solid-liquid separation and recycling of drilling fluid during petroleum drilling, a new type of solid-liquid separation device was designed and developed to achieve high-efficiency solid-liquid separation and low cost. The working principle of the equipment was introduced, the mechanical model was established, and the sieve flow of drilling fluid and the movement of wet particles in the real situation were analyzed. The relationship between the processing capacity of the solid-liquid separator and the speed of the solid phase in the drilling fluid and the speed of the excitation motor and the rotary drum were given. multi-objective evolutionary algorithm was used to solve the multi-objective optimization model. Two typical evolutionaryalgorithms NSGA-II and MOEA/D were analyzed. An algorithm that solves this problem was selected and improved. A series of optimal solution sets for this problem were obtained by using the improved multi-objective evolutionary algorithm. Finally, based on the experimental prototype of the solid-liquid separator, a functional experiment was performed on the basis of the calculated optimal solution set. The experimental results show the feasibility of the multi-objective optimization model and algorithm.
In recent years, inferring phylogenies has attracted lots of attention in both academic community and various application fields. Phylogenetic inference usually consists of a couple of evolutionary relationships, whic...
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In recent years, inferring phylogenies has attracted lots of attention in both academic community and various application fields. Phylogenetic inference usually consists of a couple of evolutionary relationships, which can be represented as a phylogenetic tree. The phylogenetic reconstruction problem can be defined as an optimization problem, targeting at finding the most eligible tree among all possible topologies according to a selected criterion. Since the combinatorial number of possible topologies exceeds tolerance, various heuristic and metaheuristic methods have been proposed to find approximate solutions according to the selected criterion. However, different criterions are based on different principle and conflict with each other basically. In this line, scholars has proposed multi-objective evolutionary algorithm (MOEA) based on diverse criteria. Nevertheless, MOEA has suffered unbearable time consumption due to its inherent drawbacks of computational complexity and convergence. By studying the independence between the sub-populations in each time-consuming step of MOEA, the steps without global information can be designed to be executed in parallel, which can fundamentally address computational problems. Effective parallel algorithms designed with the characteristics of modern multicore clusters can solve such problems. In this sense, we propose a parallelized multi-objective evolutionary algorithm (MOEA-MC) by deploying on Spark, which added consensus into evolutionaryalgorithm to improve the quality of convergence and used membrane structure to keep equal solutions under different weights. In order to assess the performance achieved by the proposal, we have performed comparison among different methods on three real-world datasets separately. The results have certified that the solutions derived from MOEA-MC are superior to traditional methods in all studied datasets. And parallelized MOEA-MC can get dominant position and optimal Pareto-frontier simulta
objective: accurately classifying the malignancy of lesions detected in a screening scan is critical for reducing false positives. Radiomics holds great potential to differentiate malignant from benign tumors by extra...
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objective: accurately classifying the malignancy of lesions detected in a screening scan is critical for reducing false positives. Radiomics holds great potential to differentiate malignant from benign tumors by extracting and analyzing a large number of quantitative image features. Since not all radiomic features contribute to an effective classifying model, selecting an optimal feature subset is critical. Methods: this work proposes a new multi-objective based feature selection (MO-FS) algorithm that considers sensitivity and specificity simultaneously as the objective functions during feature selection. For MO-FS, we developed a modified entropy-based termination criterion that stops the algorithm automatically rather than relying on a preset number of generations. We also designed a solution selection methodology for multi-objective learning that uses the evidential reasoning approach (SMOLER) to automatically select the optimal solution from the Pareto-optimal set. Furthermore, we developed an adaptive mutation operation to generate the mutation probability in MO-FS automatically. Results: we evaluated the MO-FS for classifying lung nodule malignancy in low-dose CT and breast lesion malignancy in digital breast tomosynthesis. Conclusion: the experimental results demonstrated that the feature set selected by MO-FS achieved better classification performance than features selected by other commonly used methods. Significance: the proposed method is general and more effective radiomic feature selection strategy.
Most current multi-optimization survey papers classify methods into broad objective categories and do not draw clear boundaries between the specific techniques employed by these methods. This may lead to the misclassi...
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Most current multi-optimization survey papers classify methods into broad objective categories and do not draw clear boundaries between the specific techniques employed by these methods. This may lead to the misclassification of unrelated methods/techniques into the same objective category. Moreover, most of these survey papers classify algorithms as independent of the specific techniques they employ. Toward this end, we introduce in this survey paper a methodology-based taxonomy that classifies multi-optimization methods into hierarchically nested, fine-grained, and specific classes. We provide a methodological taxonomy to classify methods into the following hierarchical fashion: objective categories objective functionsoptimization methodsoptimization sub-methods. We introduce a comprehensive survey on the methods that are contained under each optimization method, the optimization methods contained under each objective function, and objective functions contained under each objective category. We selected the objective functions that should be maximized for solving most real-word multi-objective optimization problems, which are pairs of the following: partitions separability, internal density, dynamic similarity, and structural similarity. For each optimization method, we surveyed the various algorithms in literature that pertain to the method. We experimentally compared and ranked the optimization methods that fall under each objective function, the objective functions that fall under each objective category, and the objective categories used for solving a specific optimization problem.
Seismic History Matching (SHM) is a key problem in the geosciences community, requiring optimal parameters of a subsurface model that match the observed data from multiple in-situ measurements. Therefore, the SHM prob...
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Seismic History Matching (SHM) is a key problem in the geosciences community, requiring optimal parameters of a subsurface model that match the observed data from multiple in-situ measurements. Therefore, the SHM problems are usually solved with multi-objective evolutionary algorithms (MOEAs). This group of algorithms optimize multiple objectives simultaneously, considering the trade-off between objectives. However, SHM requires the solutions that are good on all objectives rather than a trade-off. In this study, we propose a Differential Evolution algorithm using Lexicase Selection to solve the SHM problems. Unlike the MOEAs, this selection method pushes the solutions to perform well on all objectives. We compared this method with two MOEAs, namely Non-dominated Sorting Genetic algorithm II and Reference Vector-guided evolutionaryalgorithm, on two SHM problems. The results show that this method generates more solutions near the ground truth.
This paper presents an optimal design for a nanogrid/microgrid for desert camps in the city of Hafr Al-Batin in Saudi Arabia. The camps were designed to operate as separate nanogrids or to operate as an interconnected...
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This paper presents an optimal design for a nanogrid/microgrid for desert camps in the city of Hafr Al-Batin in Saudi Arabia. The camps were designed to operate as separate nanogrids or to operate as an interconnected microgrid. The hybrid nanogrid/microgrid considered in this paper consists of a solar system, storage batteries, diesel generators, inverter, and load components. To offer the designer/operator various choices, the problem was formulated as a multi-objective optimization problem considering two objective functions, namely: the cost of electricity (COE) and the loss of power supply probability (LPSP). Furthermore, various component models were implemented, which offer a variety of equipment compilation possibilities. The formulated problem was then solved using the multi-objective evolutionary algorithm, based on both dominance and decomposition (MOEA/DD). Two cases were investigated corresponding to the two proposed modes of operation, i.e., nanogrid operation mode and microgrid operation mode. The microgrid was designed considering the interconnection of four nanogrids. The obtained Pareto front (PF) was reported for each case and the solutions forming this front were discussed. Based on this investigation, the designer/operator can select the most appropriate solution from the available set of solutions using his experience and other factors, e.g., budget, availability of equipment and customer-specific requirements. Furthermore, to assess the quality of the solutions found using the MOEA/DD, three different methods were used, and their results compared with the MOEA/DD. It was found that the MOEA/DD obtained better results (nondominated solutions), especially for the microgrid operation mode.
In the current study, a plate heat exchanger model is optimised using a multi-objective evolutionary algorithm/decomposition. Considering the importance of the thermal efficiency and the cost of manufacturing the heat...
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In the current study, a plate heat exchanger model is optimised using a multi-objective evolutionary algorithm/decomposition. Considering the importance of the thermal efficiency and the cost of manufacturing the heat exchangers, these two parameters are used as objective functions during the optimisation process. For the purpose of analysis, the epsilon-NTU method was applied to analyse the probability values for the pressure drop and efficiency of the heat exchanger. The experimental data for the analysis were extracted from a gas furnace in a ceramics factory located in the Kerman province. The results of the analysis reported 19.962% enhancement in the efficiency rate as well as 9.533% reduction in cost through the proposed model, which indicated a significant improvement. In another section of this study, by performing a Pareto front analysis, the distribution of the optimum points for the design variables was outlined. As well as that, the correlation between the objective functions and the design variables by employing the artificial neural networks was discussed. The obtained results were then compared with the two reference cases to achieve a better insight towards the new developed model scheme. At the last stage of study, an error analysis concluded that in most cases, the performance and cost error rates are close to zero with the maximum values being in the range of 0.6-1 and 0-0.13, respectively.
In this article we describe the use of a multi-objective evolutionary algorithm for portfolio optimisation based on historical data for the S&P 500. Portfolio optimisation seeks to identify manageable investments ...
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ISBN:
(纸本)9781467318037
In this article we describe the use of a multi-objective evolutionary algorithm for portfolio optimisation based on historical data for the S&P 500. Portfolio optimisation seeks to identify manageable investments that provide a high expected return with relatively low risk. We developed a set of metrics for qualifying the risk/return characteristics of a portfolio's historical performance and combined this with an island model genetic algorithm to identify optimised portfolios. The algorithm was successful in selecting investment strategies with high returns and relatively low volatility. However, although these solutions performed well on historical data, they were not predictive of future returns, with optimised portfolios failing to perform above chance. The implications of these findings are discussed.
Wireless sensor networks consist of many sensor nodes with limited resources and computing capability. Thus, managing energy consumption to prolong network lifetime is a critical issue. Several approaches have been pr...
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Wireless sensor networks consist of many sensor nodes with limited resources and computing capability. Thus, managing energy consumption to prolong network lifetime is a critical issue. Several approaches have been proposed to extend the network lifetime, one of which involves deploying relay nodes to transfer data from sensors to the base station. However, the limited number of relay nodes is a challenge that often goes overlooked. This paper examines the problem of optimizing the network lifetime and the number of relay nodes in three-dimensional terrains. A novel algorithm called MOEA/D-LS is proposed with the aim of obtaining a better tradeoff between two objectives. The algorithm is a hybridization between multiobjectiveevolutionaryalgorithm based on decomposition, and a special local search to optimize the former's subproblems. Simulation results on 3D datasets show that the proposed algorithm has a significantly better performance compared with existing algorithms on all measured metrics. (C) 2021 Elsevier B.V. All rights reserved.
The multi-objective vehicle routing problem with stochastic demand (MO-VRPSD) is much harder to tackle than other traditional vehicle routing problems (VRPs), due to the uncertainty in customer demands and potentially...
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The multi-objective vehicle routing problem with stochastic demand (MO-VRPSD) is much harder to tackle than other traditional vehicle routing problems (VRPs), due to the uncertainty in customer demands and potentially conflicted objectives. In this paper, we present an improved multi-objective learnable evolution model (IMOLEM) to solve MO-VRPSD with three objectives of travel distance, driver remuneration and number of vehicles. In our method, a machine learning algorithm, i.e., decision tree, is exploited to help find and guide the desirable direction of evolution process. To cope with the key issue of "route failure" caused due to stochastic customer demands, we propose a novel chromosome representation based on priority with bubbles. Moreover, an efficient nondominated sort using a sequential search strategy (ENS-SS) in conjunction with some heuristic operations are leveraged to handle the multi-objective property of the problem. Our algorithm is evaluated on the instances of modified Solomon VRP benchmark. Experimental results show that the proposed IMOLEM is capable to find better Pareto front of solutions and also deliver superior performance to other evolutionaryalgorithms. (C) 2021 Elsevier B.V. All rights reserved.
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