4,138 research outputs found
If appleseed had an open portal : making sense of data, SEIS and integrated systems for the Maltese Islands
Much sought and realistically distant, an open data system can serve as the Holy Grail for many a policy-maker and decision taker as well as the operational entities involved in the field. The steady seeding of data-related legislative tools has aided the setting up of exploratory and active systems that serve the concept of data-information-knowledge-action to academia, the general public and the implementing agencies. Legislation, inclusive of Data Protection, Freedom of Information, Public Sector Information, Aarhus, INSPIRE, SEIS and the still embryonic SENSE, have all managed to create a new reality that may be too complex for some still caught in a jurassic analogue stage where data hoarding might still be prevalent and little effort is made to jump to the post-modern reality. Efforts to push the process through various domains such as census, environment protection, spatial development and crime have helped the Maltese Islands to create a scenario that is ripe for a national data infrastructure, inter-entity data exchange, open data structuring, and free dissemination services. This process enhances the knowledge-base and reduces redundancy, whilst creating new challenges on how to make sense of all the data being made available, particularly in the interpretation or misinterpretation of the outputs. The paper reviews Malta’s process to go through the birth pains of SEIS as an open data construct, through to the dissemination of various spatial datasets and the first open portals pertaining to the various regulatory directives.peer-reviewe
Connecting geodata initiatives to contribute to a European spatial data infrastructure : the CRISOLA case for Malta and the project Plan4all
The Malta CRISOLA case study is investigated in terms of its analysis of the approaches taken to ensure that data in the physical and social domains are tackled within a reliable structure as that provided by the spatial domain through INSPIRE. The crime, social and landuse themes, being pivotal to the model, have served as a bridge across the landuse domains identified as fundamental in the INSPIRE Directive and as expressed in the Plan4all project. The case study is described in terms of its eventual take-up of functions developed by the Plan4all project which are essential for the future successful outcomes as identified in the CRISOLA model. The idea is to disseminate Maltese results to other geoportals including Plan4all geoserver which focuses on the interoperability and harmonisation of spatial planning data. The aims are to support holistic planning through the provision of data services across the spatial and social themes.peer-reviewe
Removing inefficiencies from scientific code : the study of the Higgs boson couplings to top quarks
Publicado em "Computational science and its applications – ICCSA 2014 : proceedings", Series : Lecture notes in computer science, vol. 8582This paper presents a set of methods and techniques to remove inefficiencies in a data analysis application used in searches by the ATLAS Experiment at the Large Hadron Collider. Profiling scientific code helped to pinpoint design and runtime inefficiencies, the former due to coding and data structure design. The data analysis code used by groups doing searches in the ATLAS Experiment contributed to clearly identify some of these inefficiencies and to give suggestions on how to prevent and overcome those common situations in scientific code to improve the efficient use of available computational resources in a parallel homogeneous platform.This work is funded by National Funds through the FCT - Fundaçãoo para a Ciência e a Tecnologia (Portuguese Foundation for Science and Technology) within project PEst-OE/EEI/UI0752/2014, by LIP (Laborat ́orio de Instrumentação e Física Experimental de Partículas), and the SeARCH cluster (REEQ/443/EEI/2005)
Improving efficiency of a multistart with interrupted Hooke-and-Jeeves filter search for solving MINLP problems
Publicado em: "Computational science and its applications – ICCSA 2016: 16th International Conference, Beijing, China, July 4-7, 2016, Proceedings, Part I". ISBN 978-3-319-42084-4This paper addresses the problem of solving mixed-integer
nonlinear programming (MINLP) problems by a multistart strategy that
invokes a derivative-free local search procedure based on a filter set
methodology to handle nonlinear constraints. A new concept of componentwise
normalized distance aiming to discard randomly generated
points that are sufficiently close to other points already used to invoke
the local search is analyzed. A variant of the Hooke-and-Jeeves filter
algorithm for MINLP is proposed with the goal of interrupting the iterative
process if the accepted iterate falls inside an -neighborhood of an
already computed minimizer. Preliminary numerical results are included.FCT - Fundação para a Ciência e Tecnologia, within the projects UID/CEC/00319/2013 and UID/MAT/00013/2013.COMPETE: POCI-01- 0145-FEDER-00704
Volume CVI, Number 19, April 14, 1989
Institute of High Performance Computing, IHPC;University of Perugia, Italy;University of Calgary, Canada;University of Minnesota, MN, USA;Queen's University BelfastInternational Conference on Computational Science and Its Applications - ICCSA 2005 -- 9 May 2005 through 12 May 2005 -- 65625Discrete mathematics is one of the very basic mathematics courses in computer engineering (CE) and/or computer science (CS) departments. This course covers almost all of the basic concepts for many other courses in the curriculum and requires active learning of students. For this purpose, especially "propositions" concept, which cannot be understood well in prior years, should be covered with every detail. Previous studies show that learning by entertaining activities and competition has positive effect on student motivation. In this study, an Internet-based Discrete Mathematics Package (DMP) for "propositions" that can work in mobile devices and encourages competitive learning between students has been developed within related literature. © Springer-Verlag Berlin Heidelberg 2005
Direct sequential based firefly algorithm for the α-pinene isomerization problem
Publicado em: "Computational science and its applications – ICCSA 2016: 16th International Conference, Beijing, China, July 4-7, 2016, Proceedings, Part I"The problem herein addressed is a parameter estimation
problem of the α-pinene process. The state variables of this bioengineering
process satisfy a set of differential equations and depend on a
set of unknown parameters. A dynamic system based parameter estimation
problem aiming to estimate the model parameter values in a way
that the predicted state variables best fit the experimentally observed
state values is used. A numerical direct method, known as direct sequential
procedure, is implemented giving rise to a finite bound constrained
nonlinear optimization problem, which is solved by the metaheuristic
firefly algorithm (FA). A Matlab programming environment is developed
with the mathematical model and the computational application
of the method. The results produced by FA, when compared to those of
the fmincon function and other metaheuristics, are competitive.COMPETE: POCI-01- 0145-FEDER-007043FCT - Fundação para a Ciência e Tecnologia, within the projects UID/CEC/00319/2013 and UID/MAT/00013/201
Extensions of firefly algorithm for nonsmooth nonconvex constrained optimization problems
Publicado em: "Computational science and its applications – ICCSA 2016: 16th International Conference, Beijing, China, July 4-7, 2016, Proceedings, Part I". ISBN 978-3-319-42084-4Firefly Algorithm (FA) is a stochastic population-based algorithm
based on the flashing patterns and behavior of fireflies. Original FA was created
and successfully applied to solve bound constrained optimization problems. In
this paper we present extensions of FA for solving nonsmooth nonconvex
constrained global optimization problems. To handle the constraints of the
problem, feasibility and dominance rules and a fitness function based on the
global competitive ranking, are proposed. To enhance the speed of convergence,
the proposed extensions of FA invoke a stochastic local search procedure.
Numerical experiments to validate the proposed approaches using a set of well
know test problems are presented. The results show that the proposed extensions
of FA compares favorably with other stochastic population-based methods.COMPETE: POCI-01-0145- FEDER-007043FCT – Fundação para a Ciência e Tecnologia within the projects UID/CEC/00319/2013 and UID/MAT/00013/201
Zeros of Orthogonal Polynomials Generated by the Geronimus Perturbation of Measures
Proceedings of: 14th International Conference Computational Science and Its Applications (ICCSA 2014). Guimarães, Portugal, June 30 – July 3, 2014This paper deals with monic orthogonal polynomial sequences
(MOPS in short) generated by a Geronimus canonical spectral transformation
of a positive Borel measure μ, i.e., (x−c)
−1dμ(x)+Nδ(x−c),
for some free parameter N ∈ IR+ and shift c. We analyze the behavior
of the corresponding MOPS. In particular, we obtain such a behavior
when the mass N tends to infinity as well as we characterize the precise
values of N such the smallest (respectively, the largest) zero of these
MOPS is located outside the support of the original measure μ. When
μ is semi-classical, we obtain the ladder operators and the second order
linear differential equation satisfied by the Geronimus perturbed MOPS,
and we also give an electrostatic interpretation of the zero distribution
in terms of a logarithmic potential interaction under the action of an
external field. We analyze such an equilibrium problem when the mass
point of the perturbation c is located outside the support of μ
Branch and bound based coordinate search filter algorithm for nonsmooth nonconvex mixed-integer nonlinear programming problems
Publicado em "Computational science and its applications – ICCSA 2014...", ISBN 978-3-319-09128-0. Series "Lecture notes in computer science", ISSN 0302-9743, vol. 8580.A mixed-integer nonlinear programming problem (MINLP) is a problem with continuous and integer variables and at least, one nonlinear function. This kind of problem appears in a wide range of real applications and is very difficult to solve. The difficulties are due to the nonlinearities of the functions in the problem and the integrality restrictions on some variables. When they are nonconvex then they are the most difficult to solve above all. We present a methodology to solve nonsmooth nonconvex MINLP problems based on a branch and bound paradigm and a stochastic strategy. To solve the relaxed subproblems at each node of the branch and bound tree search, an algorithm based on a multistart strategy with a coordinate search filter methodology is implemented. The produced numerical results show the robustness of the proposed methodology.This work has been supported by FCT (Fundação para a Ciência e aTecnologia) in the scope of the projects: PEst-OE/MAT/UI0013/2014 and PEst-OE/EEI/UI0319/2014
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