Optimization of cable logging layout using a heuristic algorithm for network programming.

摘要

This study develops a methodology with the purpose of assisting the planners in designing cable logging unit layout. The methodology combines a cable logging operation planning problem with a road network planning problem and optimizes them simultaneously. It incorporates modern computer software languages, Geographic Information System (GIS) technology, and optimization techniques that have become available during the last two decades. The methodology includes logging feasibility and cost analysis to evaluate alternative cable roads and yarding equipment. Once the feasible cable road alternatives are identified, the methodology formulates two cost minimization network problems. The networks represent variable and fixed costs associated with yarding and truck transportation activities to move logs from the stump to the mill. The methodology uses a heuristic network algorithm as an optimization technique to solve the network problems. One of the two cost minimization network problems is for cable logging operation planning and the other is for truck transportation planning. Each of the network problems is solved separately using the heuristic network algorithm while being connected to the other by a feedback mechanism.; The methodology is implemented in a computerized model that can be used as a decision support system. The model is applied to an actual harvest area of 93 ha. A total of 40 candidate landing locations with 2,880 cable roads from 2 yarding equipment alternatives were evaluated. The model found 1,719 feasible cable road alternatives by conducting the logging feasibility and cost analysis. Two cost minimization network problems were developed. A total of 141,139 links and 1,926 timber parcels were developed in the network problem for cable logging paths. In the network for solving road location problem, a total of 95,904 links were developed to connect 13,522 grid cells included in the planning area. After 47.2 hours for 10 repetitions on Pentium III 1GHz speed desktop computer, the heuristic network algorithm solved these network problems and selected a total of 19 landings and 155 cable roads to harvest 8,064 m3 of logs from 1,926 timber parcels over the planning area. A total of 2.85 kilometers of new access roads were proposed as a part of the solution for this application. Overall yarding and road costs for timber harvest in the planning area was {dollar}416,675 ({dollar}51.67/m3).* (Abstract shortened by UMI.); *This dissertation is a multimedia document (contains text and other applications not available in printed format). The CD requires the following system requirements: Windows 95 or higher; Microsoft Paint.