Effect of decision variable definition and data aggregation on a search process applied to a single-tree simulator

2001 ◽  
Vol 31 (6) ◽  
pp. 1057-1066 ◽  
Author(s):  
Peder Wikström
Keyword(s):  
Tabu Search ◽  
Data Aggregation ◽  
Net Present Value ◽  
Planning Horizon ◽  
Solution Technique ◽  
Search Process ◽  
Decision Variable ◽  
Stand Management ◽  
Harvest Timing ◽  
Execution Times

This paper focuses on how computer execution times and net present value (NPV) are affected by different groupings of tree-selection harvest controls, different procedures to determine harvest timing, and tree data aggregation. The problems related to stand management are viewed as a hierarchy, where the main problem is determining harvest periods and the subordinate problem is determining what trees to cut in a given set of harvest periods. The solution technique is a derivative-free search process, and the objective is to maximize the NPV of harvest revenues for a stand over a given planning horizon. The tree-selection harvest controls are based on diameter and species groupings. The procedure to determine harvest timing is based on Tabu search and fixed cutting cycles, respectively. Sensitivity analysis is performed for a selection of stands in southern Sweden, where each stand is represented by a set of inventoried plots. Both even-aged and uneven-aged management are considered. Solutions improved with the number of decision variables. The Tabu search procedure proved very efficient at determining harvest periods for the even-aged problems. For the uneven-aged problems, fixed cutting cycles approximated the harvest timing problem, but at considerably shorter execution times. It is suggested that aggregated data be used for determining harvest timing, after which, using the original nonaggregated data, the tree-selection problem for a given set of harvest periods can be resolved.

Intensifying a heuristic forest harvest scheduling search procedure with 2-opt decision choices

1999 ◽  
Vol 29 (11) ◽  
pp. 1784-1792 ◽  
Author(s):  
Pete Bettinger ◽  
Kevin Boston ◽  
John Sessions
Keyword(s):  
Heuristic Search ◽  
Planning Horizon ◽  
Efficient Solutions ◽  
Search Process ◽  
Harvest Scheduling ◽  
Time Period ◽  
Harvest Timing ◽  
Management Problems ◽  
Decision Choices ◽  
Feasible Solutions

Forest management problems with even-flow and adjacency considerations are difficult to solve optimally. A heuristic search intensification process, which uses two types of decision procedures, changes to single-decision choices (1-opt moves) and changes to two-decision choices simultaneously (2-opt moves), was used in an attempt to locate feasible and efficient solutions to these problems. One-opt moves involve changing the timing of timber harvests for a single land unit and are commonly used in heuristic techniques. Two-opt moves involve swapping the harvest timing between two land units, which intensify the search process. We apply the procedures to two management problems, one with 40 land units and the other with 700 land units. The goal is to achieve the highest, and most even, flow of timber volume over five time periods, with adjacent units being unavailable for harvest in the same period. One-opt moves, used alone, allowed the search process to produce good feasible solutions to these management problems and to generate a relatively even spread (number) of harvests over the planning horizon. The use of 2-opt moves resulted in better solutions, although the number of harvests per time period remained static. These procedures, used alone, may not be appropriate for all problems, because of their nature and limitations.

scholarly journals Economic viability of cerrado vegetation management under conditions of risk

CERNE ◽  
2011 ◽  
Vol 17 (2) ◽  
pp. 141-149
Author(s):  
Simão Corrêa da Silva ◽  
Antonio Donizette de Oliveira ◽  
Luiz Moreira Coelho Junior ◽  
José Luiz Pereira de Rezende
Keyword(s):  
Net Present Value ◽  
Basal Area ◽  
Planning Horizon ◽  
Vegetation Management ◽  
Minas Gerais ◽  
Wood Charcoal ◽  
Economic Viability ◽  
Charcoal Production ◽  
Cerrado Vegetation ◽  
Additional Information

Cerrado vegetation is Brazil's second largest biome, comprising about 388 municipalities in Minas Gerais state alone and serving as an important source of natural resources. A large share of the wood charcoal produced in Minas Gerais is sourced from Cerrado vegetation. The objective of this work is to assess the economic viability of Cerrado vegetation management for wood charcoal production, under conditions of risk. The study site is a fragment of Cerrado subjected to five levels of intervention as to basal area removal. For risk analysis, the Monte Carlo method was applied, using charcoal price, interest rate and land value as input variables, and using Net Present Value as output variable over an infinite planning horizon. It was concluded that introducing risk in the economic analysis of the various Cerrado management regimes helped provide additional information to that obtained by deterministic analysis, improving understanding and ensuring safety in decision-making about the economic viability of such regimes. For all treatments, the probability of VPL being negative increases with increasing cutting cycle lengths. For all treatments, the optimal cutting cycle is ten years. Treatments where a larger volume of wood was removed proved less prone to risks of economic inviability since they secure more revenue than treatments where less wood was removed.

scholarly journals VIABILIDADE ECONÔMICA DA PRODUÇÃO DE CARVÃO VEGETAL EM DOIS SISTEMAS PRODUTIVOS

FLORESTA ◽  
2014 ◽  
Vol 44 (1) ◽  
pp. 143 ◽  
Author(s):  
Aylson Costa Oliveira ◽  
Thiago Taglialegna Salles ◽  
Bárbara Luísa Corradi Pereira ◽  
Angélica De Cássia Oliveira Carneiro ◽  
Camila Soares Braga ◽  
...  
Keyword(s):  
Economic Analysis ◽  
Net Present Value ◽  
Production Systems ◽  
Planning Horizon ◽  
Economic Viability ◽  
Present Value ◽  
Charcoal Production ◽  
Average Annual Production ◽  
The Cost ◽  
Benefit Cost

O objetivo deste trabalho foi analisar a viabilidade econômica da produção de carvão vegetal em dois sistemas produtivos: oito fornos de superfície acoplados a uma fornalha para queima de gases e dez fornos do tipo “rabo-quente” sem sistema de queima de gases. Para análise econômica, definiu-se uma produção anual média igual a 1.571 metros cúbicos de carvão (mdc) e horizonte de planejamento de 12 anos, sendo propostos 2 cenários. No primeiro cenário, após a colheita da madeira, realiza-se o plantio de uma nova floresta, permanecendo o custo da madeira constante em todo o planejamento; no segundo cenário, após a colheita, considerou-se a condução da brotação, reduzindo os custos na 2ª rotação e consequentemente os custos da madeira. A análise econômica foi realizada através da determinação dos seguintes indicadores: Valor Presente Líquido (VPL), Valor Anual Equivalente (VAE), Razão Benefício/Custo (B/C) e Lucratividade. Os indicadores calculados demonstraram a viabilidade dos dois sistemas produtivos avaliados em ambos os cenários propostos, porém o sistema fornos-fornalha apresentou melhores valores para os indicadores. Conclui-se que a produção de carvão vegetal nos sistemas avaliados foram viáveis economicamente, com o sistema fornos-fornalha gerando maior lucro ao produtor de carvão.Palavras-chave: Fornos de alvenaria; análise determinística; valor presente líquido. Abstract Economic viability of charcoal production in two production systems. The objective of this study was to analyze the economic viability of charcoal production in two conversion technologies: eight surface kilns coupled to a furnace for burning gases (kilns-furnace system) and ten "rabo-quente" or traditional charcoal kilns without burning gases system. An average annual production of 1571 cubic meters of charcoal (mdc) was used to perform the economic analysis. A planning horizon of 12 years and two scenarios were proposed. In the first scenario, after harvesting the wood, the planting of a new forest was performed, and the cost of wood remained constant throughout the planning horizon. In the second scenario, after the harvest, the conduction of shooting was considered, which reduced costs in the second rotation and consequently the cost of wood. The economic analysis was performed by determining the following indicators: Net Present Value (NPV), Equivalent Annual Value (EAV) and Benefit - Cost Reason (B/C). Calculated indicators demonstrated the viability of producing charcoal in the two production systems in both scenarios proposed, but kilns-furnace system presented better values. As conclusion, production of charcoal in the evaluated systems were economically viable. Kilns-furnace system was able to generate more profit to charcoal producer.Keywords: Kilns; deterministic analysis; net present value.

Multiobjective Transportation Problem Using Fuzzy Decision Variable Through Multi-Choice Programming

2017 ◽  
Vol 8 (3) ◽  
pp. 82-96 ◽  
Author(s):  
Gurupada Maity ◽  
Sankar Kumar Roy
Keyword(s):  
Transportation Problem ◽  
Fuzzy Numbers ◽  
Real Variable ◽  
Programming Approach ◽  
Solution Technique ◽  
Decision Variable ◽  
Fuzzy Decision ◽  
Fuzzy Goal ◽  
Fuzzy Transportation Problem ◽  
New Formulation

This paper analyzes the study of Multiobjective Transportation Problem (MOTP) under the consideration of fuzzy decision variable. Usually, the decision variable in a Transportation Problem is taken as real variable. But, in this paper, the decision variable in each node is selected from a set of multi-choice fuzzy numbers. Inclusion of multiple objectives into transportation problem with fuzzy decision variable makes it a Multiobjective Fuzzy Transportation Problem (MOFTP). In this paper, a new formulation of mathematical model of MOFTP with fuzzy goal of each objective function is enlisted. Thereafter the solution technique of the formulated model is described through multi-choice goal programming approach. Finally, a numerical example is presented to show the feasibility and usefulness of this article.

Wind capacity growth in the Northwest United States: Cooptimized versus sequential generation and transmission planning

2019 ◽  
Vol 43 (6) ◽  
pp. 573-595 ◽  
Author(s):  
Patrick Maloney ◽  
Ping Liu ◽  
Qingyu Xu ◽  
James D McCalley ◽  
Benjamin F Hobbs ◽  
...  
Keyword(s):  
Pacific Northwest ◽  
Net Present Value ◽  
Cost Effective ◽  
Planning Horizon ◽  
Power Grids ◽  
Sequential Optimization ◽  
Sequential Approach ◽  
Transmission Planning ◽  
Expansion Planning ◽  
Transmission Expansion

This article demonstrates the benefits of simultaneous cooptimization on a 312-bus network representation of the Western Interconnection power grid with emphasis on The Bonneville Power Administration’s operational area in the Pacific Northwest. While generation and transmission expansion planning has traditionally been solved sequentially, simultaneous cooptimization of both guarantees plans at least as cost effective as sequential approaches and better integrates high-quality remote resources like wind into power grids. For three scenarios with varied carbon and transmission costs, results indicate that (1) simultaneous cooptimization provides up to 6 billion dollars in net present value benefits over sequential optimization during the 50-year planning horizon, (2) cooptimization is more adept at tapping into superior remote resources like wind that the sequential approach has trouble identifying for low iterations, and (3) 10 iterations of sequential cooptimization only capture 75%–96% of the transmission benefits of simultaneous cooptimization.

scholarly journals Profit-Maximizing Dairy Sire Selection Package

1988 ◽  
Vol 20 (1) ◽  
pp. 141-144 ◽  
Author(s):  
Robert W. Blake ◽  
C. Richard Shumway ◽  
Michael A. Tomaszewski ◽  
Greg P. Rickard ◽  
John M. LaBore
Keyword(s):  
Net Present Value ◽  
Planning Horizon ◽  
Economic Factors ◽  
Objective Functions ◽  
Present Value ◽  
Herd Management ◽  
C Language ◽  
Performance Factors ◽  
Microcomputer Program ◽  
Dairy Sire

AbstractThe Net Present Value Sire Summary Professional Package (NPVSS) is a microcomputer program designed for technical personnel to help dairy producers better manage investments in genetic improvement. NPVSS is written in C language, utilizes the MS-DOS operating system, and requires 256K of RAM. It is menu driven and includes parameter screens to define herd management characteristics of individual producers. Profit rankings of bulls can be generated to evaluate alternative: a) objective functions (selection policies for genetic merit in milk income and type scores), b) herd management performance factors (conception rate, calving interval, age at first calving), and c) economic factors (milk price, semen price, discount rate, planning horizon).

Direct Solution of Fuzzy Project Crashing Problem with Fuzzy Decision Variables using Tabu Search and Simulated Annealing Algorithms

2017 ◽  
Vol 6 (1) ◽  
pp. 17-35 ◽  
Author(s):  
Tolunay Göçken
Keyword(s):  
Simulated Annealing ◽  
Tabu Search ◽  
Normal Activity ◽  
Transformation Process ◽  
Decision Variable ◽  
Fuzzy Decision ◽  
Project Duration ◽  
Decision Variables ◽  
Important Field ◽  
Annealing Algorithms

Project management is a very important field employed for scheduling activities and monitoring the progress, in competitive and fluctuating environments. Project crashing analysis is concerned with shortening the project duration time by accelerating some of its activities at an additional cost. In reality, because of uncertain environment conditions there can be ambiguity in the parameters of the problem. The uncertainty in the parameters can be modeled via fuzzy set theory. Using fuzzy models give the chance of better project scheduling with more stability under uncertain environmental factors. In this study, a fuzzy project crashing problem with fuzzy decision variable - occurrence time of events - and fuzzy normal activity duration times is handled. The fuzzy project crashing problem is solved without any transformation process by employing a fuzzy ranking method and the tabu search and simulated annealing algorithms.

Seed Orchard Replacement Guidelines: A Linear Programming Approach

1991 ◽  
Vol 15 (3) ◽  
pp. 117-125
Author(s):  
Jay O'Laughlin ◽  
Christopher M. Whatley ◽  
Craig R. McKinley
Keyword(s):  
Linear Programming ◽  
Net Present Value ◽  
Programming Model ◽  
Seed Orchard ◽  
Planning Horizon ◽  
Linear Programming Model ◽  
Programming Approach ◽  
Specific Production ◽  
Present Value ◽  
Linear Programming Approach

Abstract A linear programming model is used to determine when to replace a seed orchard with subsequent rotations reflecting additional genetic improvements. The objective is to maximize the net present value of the orchard while meeting specific production targets of exactly 1,000 pounds of seed per year. The solution calls for a 39 ac orchard over the 50-year planning horizon, and provides a schedule indicating both when and how much of the orchard is to be replaced. Slightly more than half (55%) of the first orchard rotation is replaced between years 13 and 21—roughly 13% in year 13, 14% in year 15, 16% in year 17, 4% in year 19, and 8% in year 21. The remaining 45% of the orchard is replaced at the maximum orchard age of 25. To meet production needs in years 25 through 34 without using additional orchard acreage, 2,550 pounds of surplus seed are produced between years 13 and 24. South. J. Appl. For. 15(3):117-125.

scholarly journals Assessment of Broad-Leaved Forest Stand Management

2019 ◽  
Vol 40 (2) ◽  
pp. 365-375 ◽  
Author(s):  
Yasushi Suzuki ◽  
Tetsuhiko Yoshimura
Keyword(s):  
Interest Rates ◽  
Net Present Value ◽  
Road Construction ◽  
Japanese Cedar ◽  
Charcoal Production ◽  
Fast Growing ◽  
Stand Management ◽  
Growing Stock ◽  
Large Trees ◽  
Quercus Glauca

There are many broad-leaved forests in Japan that were formerly managed for charcoal production, which have been abandoned for decades. Appropriate thinning can revitalize these forests if the cost balance of the management is positive. Two critical elements are the construction of spur roads to facilitate mechanized harvesting operations and management planning that considers stand properties such as the growing stock, species, and tree size distribution. We surveyed three abandoned former broad-leaved coppice stands; one coastal, one cool temperate and one warm temperate. The stock in all three stands exceeded 300 m3 ha-1, two- to three-fold the official forest registry data estimates. The dominant species in terms of tree numbers are Castanopsis sieboldii, Pieris japonica, and Quercus glauca. Medium-sized trees involve those well suited for firewood, i.e., Quercus acuta, Quercus glauca, Quercus serrata, etc. Each plot contained a few large trees that potentially have a high market value, e.g., Cinnamomum camphora, Zelkova serrata, Abies firma, etc. The average income from harvested trees was estimated to be 10200 JPY (Japanese Yen) m-3, whereas the thinning costs would be 3200 to 5400 JPY m-3, with the additional spur road construction costs. The management cost balance of a broad-leaved stand in a 60 year rotation was evaluated with both Net Present Value (NPV) (for interest rates of 1, 2, 3, and 4%) and Internal Rate of Return (IRR). This balance was compared with that of a typical plantation stand of Japanese cedar (Cryptomeria japonica) and of a fast-growing plantation stand of Chinese fir (Cunninghamia lanceolata). The estimated NPVs were largest for the fast-growing plantation stand, second largest for the typical plantation stand, and lowest for the broad-leaved stand with a NPV interest rate of 1 + %. However, the IRR of the broad-leaved stand was the highest, followed by that of the fast-growing plantation stand, while the IRR of the typical plantation stand was the lowest. This order was the same for NPVs assuming higher interest rates. 1 JPY=0.0086 € on April 29, 2019.

A dynamic programming algorithm for optimization of uneven-aged forest stands

1994 ◽  
Vol 24 (9) ◽  
pp. 1758-1765 ◽  
Author(s):  
David J. Anderson ◽  
B. Bruce Bare
Keyword(s):  
Dynamic Programming ◽  
Interest Rates ◽  
Net Present Value ◽  
Initial Conditions ◽  
Dynamic Programming Algorithm ◽  
Basal Area ◽  
Management Problem ◽  
Present Value ◽  
Stand Management ◽  
The Impact

A deterministic dynamic programming formulation of the transition uneven-aged stand management problem is presented. Using a previously published northern hardwoods growth model, a forward recursive, discrete, two-state problem that maximizes the net present value of harvested trees at each stage is developed. State variables represent the total number of trees and the total basal area per acre. A neighborhood storage concept previously published is used to reduce the number of states considered at each stage. Two harvest allocation rules are used to assign the harvested basal area to individual diameter classes. Terminal end point conditions and stage to stage sustainability are not required. Results from four base runs of the model are presented and compared with previously published results. Each run produces significantly different optimal paths, with one showing a higher net present value than any previously published. Sensitivity runs illustrate the impact of changes in interest rates, width of neighborhood storage class, and initial conditions. Dynamic programming offers promise for analyzing uneven-aged stand management problems.

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