1,721,013 research outputs found
Otimização do manejo florestal em uma empresa do estado do Paraná, considerando a fixação de carbono
No full textEste estudo foi realizado nas áreas de reflorestamento da Indústria Pedro N. Pizzatto, localizada na região de General Carneiro, Centro-Sul do Paraná, com o objetivo geral de modelar o planejamento florestal otimizado de longo prazo visando maximizar o lucro da empresa florestal em questão, levando em consideração o estoque de carbono existente nas florestas com o decorrer dos tratamentos silviculturais. O estudo apresentou os seguintes objetivos específicos: estimar o volume de sortimento retirado nos desbastes e no corte raso, em 11 projetos, utilizando 4 simulações de regimes de manejo além do regime de manejo atual da empresa; estimar a quantidade de carbono (C), existente acima do solo, que é retirada nos desbastes simulados para cada regime de manejo e para os projetos, assim como a quantidade remanescente dessa variável;
apresentar a quantidade total de carbono que seria fixada aos 20 anos para os projetos
e regimes de manejo estudados, verificando se existe diferença significativa entre eles;
avaliar economicamente os projetos submetidos aos diferentes regimes de manejo; identificar a melhor opção de manejo florestal para cada projeto da empresa, maximizando o lucro total e mantendo um nível de carbono na área. De posse dos dados advindos de 11 Projetos da referida empresa, utilizou-se o Software SISPINUS para prognosticar o volume, a altura e o diâmetro desses projetos, submetidos a 5
diferentes regimes de manejo, para um horizonte de planejamento de 21 anos. Através
dos resultados obtidos de diâmetro e altura estimou-se a quantidade de carbono
remanescente e retirado nos anos do horizonte de planejamento, assim como a quantidade total de carbono aos 20 anos de cada projeto com o objetivo de verificar se existe diferença significativa entre as médias encontradas para os projetos e para os
regimes de manejo. Na programação linear adotou-se 36 cenários, sendo que estes
variaram em função da demanda de madeira (exigida pela empresa, 20% menor e 30%
menor), da taxa de desconto anual (8, 10, 12 e 16,5% a.a.) e da estratégia comercial
(Compra e Venda maximizando o VPL, DownGrade minimizando a compra e DownGrade maximizando o VPL). Adotou-se também um modelo de programação em metas, onde foram estabelecidas metas de carbono (baseada no resultado obtido com o melhor cenário), metas econômicas (baseada no faturamento anual da empresa) e metas de demanda para cada sortimento. Após a análise dos resultados encontrados as seguintes conclusões podem ser tiradas: o maior volume dos sortimentos estudados (serraria, torno pequeno e torno grande) concentrou-se nos primeiros anos do horizonte de planejamento, em todos os regimes de manejo adotados, devido à idade avançada dos projetos no ano considerado como base para início do estudo; a quantidade
remanescente total de carbono, considerando todos os projetos, apresentou-se instável
durante o horizonte de planejamento, sendo a maior quantidade encontrada nos primeiros e nos últimos anos do horizonte de planejamento, nos 5 regimes de manejo adotados no estudo; comparando-se estatisticamente os regimes de manejo estudados verificou-se que estes apresentam diferenças estatísticas significantes ao nível de 5% de probabilidade, sendo que o regime da empresa e o regime 4 apresentaram as menores médias e os regimes 1, 2 e 3 as maiores médias para quantidade de carbono
total aos 20 anos de idade; com relação às médias de carbono total encontradas aos 20
anos para os projetos estudados pode-se dizer que apenas o Projeto 12 apresentou resultado significativo, sendo a maior média de todos os projetos, o que pode ser justificado pelo seu alto índice de sítio; o cenário que apresentou o melhor resultado para a função objetivo no modelo de programação linear foi o de número 5. Este cenário considera uma taxa de desconto de 8% ao ano no cálculo do Valor Presente Líquido, a compra e venda da madeira e uma demanda 30% do que a utilizada pela empresa; os projetos apresentaram áreas muito quebradas, sendo que algumas muito
pequenas. Isto pode ser causado pelo número grande de restrições impostas pelo modelo e a quebra dos projetos grandes pode estar sugerindo a criação de novas unidades de manejo. _______________________________________________________________________________________ ABSTRACT: This study was carried out in lands of the Indústrias Pedro N. Pizzatto, located in General Carneiro county, Southern-Central Paraná State, Brazil. The general objective
of the study was develop a long-term optimization forest planning model which
maximizes the revenue of the forest company, taking into consideration the carbon stocked in the forests under different management regimes. The specific objectives of the study were: to estimate the timber volume harvested by the occasion of thinnings and final cut in 11 stands, using 4 simulated management regimes besides the standard regime adopted by the company; to estimate the aboveground carbon stock (C) removed by the simulated thinnings for each management regime and stand as well as the remaining stock of this variable; to estimate the total amount of carbon captured by the forest stands in a 20-year period for each management regime and comparing the statistics of them; to evaluate the economic result of the different management regimes; to identify the best management option for each stand in the study area which maximizes the total revenue keeping a certain level of carbon in the forest. The data came from 11 stands of the company, and the SISPINUS growth and yield simulator was used to predict volume, mean tree height and dbh of these stands managed under five different options for a planning horizon of 21 years. Removed and remaining
carbon stocks of each stand were estimated through dbh and height for each management event and for the total period of time aiming at identifying significant differences among the management regimes. Linear programming techniques were applied to 36 scenarios defined as a function the log demand (required by the company, 20% less and 30% less), the annual interest rate (8, 10, 12, and 16.5% per annum), as well as the commercial strategy (purchase and sale maximizing NPV – Net Present Value, DownGrade minimizing purchase and DownGrade maximizing NPV). A goal programming approach was also used to indicate some carbon stock goals for
the best previously selected scenario, economical goals (based upon the annual income of the company) and demand goals of each log use (assortment). The results indicated the greatest volume of the assortments (sawnlog, small veneer log, long veneer log) were concentrated in the first years of the planning horizon for all management regimes due to the age of the stands used for the beginning of the analysis (the current existing stands are only mature ones). It was also noticed that the total carbon stock remaining in the stands under study was instable during the planning horizon and concentrated in the last years of the planning horizon for the five regimes under analysis. The statistical comparison among the management regimes showed
significant differences at 0.05 probability level. The current management regime used
by the company and regime 4 gave the lowest means, whereas regimes 1, 2, and 3 gave the greatest means of total carbon stock in 20 years. The best condition was reached by stand 12, the greatest mean for the most favorable site index. The best scenario indicated by the objective function in the linear programming model was number 5. This option takes into consideration an 8% interest rate for calculating NPV, purchase and sale of logs in the market and a demand of 30% of the woody raw material consumed by the factory. The stands originated after the application of the model showed irregular areas, some very small. This might be caused by the great number of restrictions imposed by the model and the conversion of large stands into small ones might be suggesting the necessity of creating new and variable
management units
Planejamento florestal otimizado via redes de manejo
No full textOrientador: Miguel Taube NettoTese (doutorado) - Universidade Estadual Campinas, Faculdade de Engenharia EletricaResumo: Não informadoAbstract: Not informedDoutoradoDoutor em Engenharia Elétric
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
A otimizaçao dos custos do transporte rodoviário de madeira roliça oriunda de reflorestamento
Get PDFThis work has as main objective to minimize the costs of the transports is the crop of reforestations, giving emphasis to the operational aspects for the definition d the characteristics techniques of the highways. For that, so much ref&riig particularities are approached to the vehicles as to the highways. In the revision & the literature and methods seven mais items are considered: 1) definition of lhe transport volumes, in other words, of the demand; 2)operational aspects; 3)definition of the transport vehicle; 4)costs of operation of Ioad vehicles; 5)planning, construction and conservation of the roads; 6)studies of economical viability and 7)environmental and social aspects including the driver& characteristics. These items are used to obtain the minimum transport costs, defining the type of more appropriate vehicle; miminum path to be accomplished by loaded and empty vehicles as well as the constructive improvements and of conservation of the road system that provide the largest economical earnings. The choice of the alternatives of improvements of the road system is related with the accomplishment of the forest transport in an optimized way. The methodologies and selected practices are applied in the reduction of the total costs of transport, existent in the wood crop, in two case studies, in areas reforested located in the south of Bahia and in the area of the plateau north catarinense. The application of the HDM III (The Highway Design and Maintenance Standards Model) Metodology is verified by the calculation of operation costs for ten types of compositions of load vehicles, used in the transport of reforested wood; different conditions are simulate for inclinations of ramps, rays õf horizontal curves and conditions of surface of the roads given by IRI (International Rougness Index) . ln the study of the demand, the methodology of the model of four stages is considered (generation, distribution, modal split and allocation); being applied to the transports forest methods used in general for transports. The constructive characteristics of the roads define the costs of operation of the types of vehicles, in this way it is possible to optimize the choice of the vehicle and the route for the transport. The techniques of accomplishment of the transports, including the definition of the road segments to be improved, the types of vehicles and aspects of economical Hfe are considered due to they mportance in the total costs. lt is verified that the benefits of the use of the methodologies proposed by the forest companies consist of 1) definition of the demand of the transport of reforested wood, 2) calculation of the costs of operation of the vehicles, 3) choice among alternatives of types of vehicles, 4) definition of optimized routes and 5) definition of the priority places for implantation of improvements in the forest highways. Being used the proposed methodologies, the actívities of forest transport in reforestations, present smaller total costs, since the operation costs are considered together with the construction costs and of conservation. Besides, the section of transports forest can know the possible earnings of their activities, what facilitates the obtaining of resources and the valorization of their works
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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