2012
Autores
Fonseca, TF; Cerveira, A; Mota, A;
Publicação
FOREST SYSTEMS
Abstract
The study addresses the special case of a management plan for maritime pine (Pinus pinaster Ait.) in common lands. The study area refers to 4,432 ha of maritime pine stands in North Portugal (Perimetro Florestal do Barroso in the county of Ribeira de Pena), distributed among five common lands called baldio areas. Those lands are co-managed by the Official Forest Services and the local communities, essentially for timber production, using empirical guidance. As the current procedure does not guarantee the best thinning and clear-cutting scheduling, it was considered important to develop "easy-to-use" models, supported by optimization techniques, to be employed by the forest managers in the harvest planning of these communitarian forests. Planning of the thinning and clear-cutting operations involved certain conditions, such as: (1) the optimal age for harvesting; (2) the maximum stand density permitted; (3) the minimum volume to be cut; (4) the guarantee of incomes for each of the five baldios in at least a two year period; (5) balanced incomes during the length of the projection period. In order to evaluate the sustainability of the wood resources, a set of constraints lower bounding the average ending age was additionally tested. The problem was formulated as an integer linear programming model where the incomes from thinning and clear-cutting are maximized while considering the constraints mentioned above. Five major scenarios were simulated. The simplest one allows for silvicultural constraints only, whereas the other four consider these constraints besides different management options. Two of them introduce joint management of all common areas with or without constraints addressing balanced distribution of incomes during the plan horizon, whilst the other two consider the same options but for individual management of the baldios. The proposed model is easy to apply, providing immediate advantages for short and mid-term planning periods compared to the empirical methods of harvest planning. Results showed that maximization of production is reached when there are silvicultural restrictions only and when forest management units are regarded as a joint undertaking. The individualized management with a balanced distribution of incomes is an interesting option as it does not drastically reduce the optimal solution while assuring benefits at least every two years.
2012
Autores
Romao, X; Goncalves, R; Costa, A; Delgado, R;
Publicação
Materials and Structures/Materiaux et Constructions
Abstract
2012
Autores
Fernandes, Sara; Cerone, Antonio; Barbosa, LuisSoares;
Publicação
Information Technology and Open Source: Applications for Education, Innovation, and Sustainability - SEFM 2012 Satellite Events, InSuEdu, MoKMaDS, and OpenCert, Thessaloniki, Greece, October 1-2, 2012, Revised Selected Papers
Abstract
It can be argued that participating in free/libre open source software (FLOSS) projects can have a positive effect in the contributor's learning process. The need to interact with other contributors, to read other people's code, write documentation, or use different tools, can motivate and implicitly foster learning. In order to validate this statement we design an appropriate questionnaire asking FLOSS contributors about their experience in FLOSS projects. In this paper, we illustrate how this questionnaire was designed and what we expect to learn from the answers. We conclude the paper with a preview of the results from three cases studies. © Springer-Verlag Berlin Heidelberg 2014.
2012
Autores
Fonseca, NA; Rung, J; Brazma, A; Marioni, JC;
Publicação
BIOINFORMATICS
Abstract
Motivation: A ubiquitous and fundamental step in high-throughput sequencing analysis is the alignment (mapping) of the generated reads to a reference sequence. To accomplish this task numerous software tools have been proposed. Determining the mappers that are most suitable for a specific application is not trivial. Results: This survey focuses on classifying mappers through a wide number of characteristics. The goal is to allow practitioners to compare the mappers more easily and find those that are most suitable for their specific problem.
2012
Autores
Saraiva, JT;
Publicação
2012 9TH INTERNATIONAL CONFERENCE ON THE EUROPEAN ENERGY MARKET (EEM)
Abstract
This paper describes the models that were used and the results obtained to estimate the Congestion Cost of the Portuguese National Transmission Network. This network is established at 400 / 220 and 150 kV and the Tariff Code in force is Portugal determines the use of a postage stamp based approach discriminated by voltage level to set the tariffs for the use of the transmission system. However, the value of the congestion cost and its percentage regarding the regulated revenue of the transmission activity set by the Regulatory Agency are good indicators of the quality of the network since they directly reflect problems in the network in terms of congested branches or larger transmission losses. In this sense, we have been computing this indicator since 1998 and this paper reports the conclusions that were recently obtained using data from 2006 and 2008.
2012
Autores
Pousinho, HMI; Contreras, J; Catalao, JPS;
Publicação
IET GENERATION TRANSMISSION & DISTRIBUTION
Abstract
This study proposes a stochastic mixed-integer linear programming approach to maximise the total expected profit of a price-maker Hydro Generating Company. Start-up and shutdown procedures, discrete hydro unit-commitment constraints, ramp rates, minimum and maximum power output constraints, and head effects, are all taken into account in an efficacious way. Uncertainties are modelled considering sets of scenarios to describe the residual demand curves. The proposed approach is successfully applied to a Portuguese hydro system in cascaded configuration. Conclusions are duly drawn.
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