34 documents found, page 1 of 4
cf4ocl: A C framework for OpenCL
Fachada, Nuno; Lopes, Vitor V.; Martins, Rui C.; Rosa, Agostinho C.OpenCL is an open standard for parallel programming of heterogeneous compute devices, such as GPUs, CPUs, DSPs or FPGAs. However, the verbosity of its C host API can hinder application development. In this paper we present cf4ocl, a software library for rapid development of OpenCL programs in pure C. It aims to reduce the verbosity of the OpenCL API, offering straightforward memory management, integrated profil...
Model-independent comparison of simulation output
Fachada, Nuno; Lopes, Vitor V.; Martins, Rui C.; Rosa, Agostinho C.Computational models of complex systems are usually elaborate and sensitive to implementation details, characteristics which often affect their verification and validation. Model replication is a possible solution to this issue. It avoids biases associated with the language or toolkit used to develop the original model, not only promoting its verification and validation, but also fostering the credibility of th...
Parallelization strategies for spatial agent-based models
Fachada, Nuno; Lopes, Vitor V.; Martins, Rui C.; Rosa, Agostinho C.Agent-based modeling (ABM) is a bottom-up modeling approach, where each entity of the system being modeled is uniquely represented as an independent decision-making agent. Large scale emergent behavior in ABMs is population sensitive. As such, the number of agents in a simulation should be able to reflect the reality of the system being modeled, which can be in the order of millions or billions of individuals i...
micompr: an R package for multivariate independent comparison of observations
Fachada, Nuno; Rodrigues, João; Lopes, Vitor V.; Martins, Rui C.; Rosa, Agostinho C.The R package micompr implements a procedure for assessing if two or more multivariate samples are drawn from the same distribution. The procedure uses principal component analysis to convert multivariate observations into a set of linearly uncorrelated statistical measures, which are then compared using a number of statistical methods. This technique is independent of the distributional properties of samples a...
Towards a standard model for research in agent-based modeling and simulation
Fachada, Nuno; Lopes, Vitor V.; Martins, Rui C.; Rosa, Agostinho C.Agent-based modeling (ABM) is a bottom-up modeling approach, where each entity of the system being modeled is uniquely represented as an independent decisionmaking agent. ABMs are very sensitive to implementation details. Thus, it is very easy to inadvertently introduce changes which modify model dynamics. Such problems usually arise due to the lack of transparency in model descriptions, which constrains how mo...
Spectrometric differentiation of yeast strains using minimum volume increase an...
Fachada, Nuno; Figueiredo, Mário A. T.; Lopes, Vitor V.; Martins, Rui C.; Rosa, Agostinho C.This paper proposes new clustering criteria for distinguishing Saccharomyces cerevisiae (yeast) strains using their spectrometric signature. These criteria are introduced in an agglomerative hierarchical clustering context, and consist of: (a) minimizing the total volume of clusters, as given by their respective convex hulls; and, (b) minimizing the global variance in cluster directionality. The method is deter...
A cyclic time-dependent Markov process to model daily patterns in wind turbine ...
Scholz, Teresa; Lopes, Vitor V.; Estanqueiro, AnaWind energy is becoming a top contributor to the renewable energy mix, which raises potential reliability issues for the grid due to the fluctuating nature of its source. To achieve an adequate reserve commitment which mitigates wind integration costs as well as to promote market participation, it is necessary to provide models that can capture daily patterns in wind power production. This paper presents a cycl...
Spectrometric differentiation of yeast strains using minimum volume increase an...
Fachada, Nuno; Figueiredo, Mário A.T.; Lopes, Vitor V.; Martins, Rui C.; Rosa, AgostinhoThis paper proposes new clustering criteria for distinguishing Saccharomyces cerevisiae (yeast) strains using their spectrometric signature. These criteria are introduced in an agglomerative hierarchical clustering context, and consist of: (a) minimizing the total volume of clusters, as given by their respective convex hulls; and, (b) minimizing the global variance in cluster directionality. The method is deter...
Impact of weather regimes on the wind power ramp forecast in Portugal
Couto, António; Costa, Paula Silva; Rodrigues, L.; Lopes, Vitor V.; Estanqueiro, AnaShort-term forecasting and diagnostic tools for severe changes of wind power production (power ramps) may provide reliable information for a secure power system operation at a small cost. Understanding the underlying role of the synoptic weather regimes (WRs) in triggering the wind power ramp events can be an added value to improve and complement the current forecast techniques. This work identifies and classif...
Dynamic testing of systems – use of TRNSYS as an approach for parameter identif...
Almeida, Patrícia; Carvalho, Maria João; Amorim, Ricardo; Mendes, J. Farinha; Lopes, Vitor V.Dynamic testing of solar thermal systems is presently defined by ISO 9459-5:2007. The testing methodology is clearly defined in the standard. Presently, laboratories that use Dynamic System Testing methodology only have available for identification of parameters, a closed source program, which is based on a model described by Spirkl and Muschawek (1992). The present paper describes the work done following a dif...