TUNING OF THE METAHEURISTIC VARIABLE NEIGHBORHOOD SEARCH FOR A FOREST PLANNING PROBLEM

Carlos Alberto Araújo Júnior,Jonathan James Stocks,João Batista Mendes,Christian Dias Cabacinha,Liniker Fernandes Da Silva,Helio Garcia Leite,Adriana Leandra De Assis

doi:10.1590/01047760201824032538

Abstract

ABSTRACT In forest science it is important evaluate new technologies from computational science. This work aimed to test a different kind of metaheuristic called Variable Neighborhood Search in a forest planning problem. The management total area has 4.210 ha distributed in 120 stands in ages between 1 and 6 years old and site index since 22 m to 31 m. The problem was modelled considering the maximization of the net present value subject to the restrictions: annual cut volume between 140.000 m³ and 160.000 m³, harvester ages equal to 5, 6 or 7 years, and the impossibility of division of the management unity at harvester time. It was evaluated different settings for the Variable Neighborhood Search, varying the quantity of neighbours, the neighbourhood structure and number or generations. 30 repetitions were performed for each setting. The results were compared to the one obtained from integer linear programming and linear programming. The integer linear programming considered the best solution obtained after 1 hour of processing. The best setting to the Variable Neighborhood Search was 100 neighbours, a neighbourhood structure with changes in 1%, 2%, 3% and 4% of prescriptions and 500 iterations. The results shown by the Variable Neighborhood Search was 2,77% worse than one obtained by the integer linear programming with 1 hours of processing, and 2,84% worse than the linear programming. It is possible to conclude that the presented metaheuristic can be used satisfactorily in a resolution of forest scheduling problem when the best parameters are chosen.

Highlights

Forest planning problems can be considered as complex in function of the amount of decision variables, imposed constraints and difficult to obtain all necessary information to develop work plans, mainly because of intrinsic characteristics of forest activities
Mathematical formulations for the optimization models were based on Model I mentioned by Jonhson and Scheurman (1977) in order to preserve the physical identity of management unit along the horizon plan
The Variable Neighborhood Search (VNS) has its processing interrupted after reach the stop criterium and the processing time ranged according to the parameters values used (Table 1)

Summary

Introduction

Forest planning problems can be considered as complex in function of the amount of decision variables, imposed constraints and difficult to obtain all necessary information to develop work plans, mainly because of intrinsic characteristics of forest activities In this sense, the effective courses-of-actions determination that maximize the enterprise economic returns or that optimize ecological and social aspects, as mentioned by Kaya et al (2016), Ezquerro et al (2016), Dong et al (2016) and Shan et al (2009), has been done with use of mathematical programming, like Linear Programming (LP), Integer Linear Programming (IP) and Mixed Integer Linear Programming (MIP) for instance (Troncoso et al, 2016). This suggests the development and application of heuristics methods (Yoshimoto et al, 2016; Jin et al, 2016; Shan et al, 2009)

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