Coupling Elephant Herding with Ordinal Optimization for Solving the Stochastic Inequality Constrained Optimization Problems

The stochastic inequality constrained optimization problems (SICOPs) consider the problems of optimizing an objective function involving stochastic inequality constraints. The SICOPs belong to a category of NP-hard problems in terms of computational complexity. The ordinal optimization (OO) method o...

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Main Authors: Shih-Cheng Horng, Shieh-Shing Lin
Format: Article
Language:English
Published: MDPI AG 2020-03-01
Series:Applied Sciences
Subjects:
Online Access:https://www.mdpi.com/2076-3417/10/6/2075
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author Shih-Cheng Horng
Shieh-Shing Lin
author_facet Shih-Cheng Horng
Shieh-Shing Lin
author_sort Shih-Cheng Horng
collection DOAJ
description The stochastic inequality constrained optimization problems (SICOPs) consider the problems of optimizing an objective function involving stochastic inequality constraints. The SICOPs belong to a category of NP-hard problems in terms of computational complexity. The ordinal optimization (OO) method offers an efficient framework for solving NP-hard problems. Even though the OO method is helpful to solve NP-hard problems, the stochastic inequality constraints will drastically reduce the efficiency and competitiveness. In this paper, a heuristic method coupling elephant herding optimization (EHO) with ordinal optimization (OO), abbreviated as EHOO, is presented to solve the SICOPs with large solution space. The EHOO approach has three parts, which are metamodel construction, diversification and intensification. First, the regularized minimal-energy tensor-product splines is adopted as a metamodel to approximately evaluate fitness of a solution. Next, an improved elephant herding optimization is developed to find <i>N</i> significant solutions from the entire solution space. Finally, an accelerated optimal computing budget allocation is utilized to select a superb solution from the <i>N</i> significant solutions. The EHOO approach is tested on a one-period multi-skill call center for minimizing the staffing cost, which is formulated as a SICOP. Simulation results obtained by the EHOO are compared with three optimization methods. Experimental results demonstrate that the EHOO approach obtains a superb solution of higher quality as well as a higher computational efficiency than three optimization methods.
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spelling doaj.art-955350e8cb294ce8845dc61c46bd3cbf2022-12-21T19:58:32ZengMDPI AGApplied Sciences2076-34172020-03-01106207510.3390/app10062075app10062075Coupling Elephant Herding with Ordinal Optimization for Solving the Stochastic Inequality Constrained Optimization ProblemsShih-Cheng Horng0Shieh-Shing Lin1Department of Computer Science and Information Engineering, Chaoyang University of Technology, Taichung 413310, TaiwanDepartment of Electrical Engineering, St. John’s University, New Taipei City 251303, TaiwanThe stochastic inequality constrained optimization problems (SICOPs) consider the problems of optimizing an objective function involving stochastic inequality constraints. The SICOPs belong to a category of NP-hard problems in terms of computational complexity. The ordinal optimization (OO) method offers an efficient framework for solving NP-hard problems. Even though the OO method is helpful to solve NP-hard problems, the stochastic inequality constraints will drastically reduce the efficiency and competitiveness. In this paper, a heuristic method coupling elephant herding optimization (EHO) with ordinal optimization (OO), abbreviated as EHOO, is presented to solve the SICOPs with large solution space. The EHOO approach has three parts, which are metamodel construction, diversification and intensification. First, the regularized minimal-energy tensor-product splines is adopted as a metamodel to approximately evaluate fitness of a solution. Next, an improved elephant herding optimization is developed to find <i>N</i> significant solutions from the entire solution space. Finally, an accelerated optimal computing budget allocation is utilized to select a superb solution from the <i>N</i> significant solutions. The EHOO approach is tested on a one-period multi-skill call center for minimizing the staffing cost, which is formulated as a SICOP. Simulation results obtained by the EHOO are compared with three optimization methods. Experimental results demonstrate that the EHOO approach obtains a superb solution of higher quality as well as a higher computational efficiency than three optimization methods.https://www.mdpi.com/2076-3417/10/6/2075stochastic inequality constraintsordinal optimizationelephant herding optimizationtensor product splineoptimal computing budget allocationmulti-skill call centerservice level
spellingShingle Shih-Cheng Horng
Shieh-Shing Lin
Coupling Elephant Herding with Ordinal Optimization for Solving the Stochastic Inequality Constrained Optimization Problems
Applied Sciences
stochastic inequality constraints
ordinal optimization
elephant herding optimization
tensor product spline
optimal computing budget allocation
multi-skill call center
service level
title Coupling Elephant Herding with Ordinal Optimization for Solving the Stochastic Inequality Constrained Optimization Problems
title_full Coupling Elephant Herding with Ordinal Optimization for Solving the Stochastic Inequality Constrained Optimization Problems
title_fullStr Coupling Elephant Herding with Ordinal Optimization for Solving the Stochastic Inequality Constrained Optimization Problems
title_full_unstemmed Coupling Elephant Herding with Ordinal Optimization for Solving the Stochastic Inequality Constrained Optimization Problems
title_short Coupling Elephant Herding with Ordinal Optimization for Solving the Stochastic Inequality Constrained Optimization Problems
title_sort coupling elephant herding with ordinal optimization for solving the stochastic inequality constrained optimization problems
topic stochastic inequality constraints
ordinal optimization
elephant herding optimization
tensor product spline
optimal computing budget allocation
multi-skill call center
service level
url https://www.mdpi.com/2076-3417/10/6/2075
work_keys_str_mv AT shihchenghorng couplingelephantherdingwithordinaloptimizationforsolvingthestochasticinequalityconstrainedoptimizationproblems
AT shiehshinglin couplingelephantherdingwithordinaloptimizationforsolvingthestochasticinequalityconstrainedoptimizationproblems