3,693 research outputs found
Solving Irregular Strip Packing Problems With Free Rotations Using Separation Lines
Solving nesting problems or irregular strip packing problems is to position
polygons in a fixed width and unlimited length strip, obeying polygon integrity
containment constraints and non-overlapping constraints, in order to minimize
the used length of the strip. To ensure non-overlapping, we used separation
lines. A straight line is a separation line if given two polygons, all vertices
of one of the polygons are on one side of the line or on the line, and all
vertices of the other polygon are on the other side of the line or on the line.
Since we are considering free rotations of the polygons and separation lines,
the mathematical model of the studied problem is nonlinear. Therefore, we use
the nonlinear programming solver IPOPT (an algorithm of interior points type),
which is part of COIN-OR. Computational tests were run using established
benchmark instances and the results were compared with the ones obtained with
other methodologies in the literature that use free rotation
On bicluster aggregation and its benefits for enumerative solutions
Biclustering involves the simultaneous clustering of objects and their
attributes, thus defining local two-way clustering models. Recently, efficient
algorithms were conceived to enumerate all biclusters in real-valued datasets.
In this case, the solution composes a complete set of maximal and non-redundant
biclusters. However, the ability to enumerate biclusters revealed a challenging
scenario: in noisy datasets, each true bicluster may become highly fragmented
and with a high degree of overlapping. It prevents a direct analysis of the
obtained results. To revert the fragmentation, we propose here two approaches
for properly aggregating the whole set of enumerated biclusters: one based on
single linkage and the other directly exploring the rate of overlapping. Both
proposals were compared with each other and with the actual state-of-the-art in
several experiments, and they not only significantly reduced the number of
biclusters but also consistently increased the quality of the solution.Comment: 15 pages, will be published by Springer Verlag in the LNAI Series in
the book Advances in Data Minin
Distribution view: a tool to write and simulate distributions
In our work we present a tool to write and simulate distributions. This tool allows to write
mathematical expressions which can contain not only functions and variables, but also
statistical distributions, including mixtures. Each time the expression is evaluated, for all
inner distributions, is generated a value according to the distribution and is used for
expression value determination. The inversion method can be used in this language,
allowing to generate all distributions that have an expression for cdf inverse. The variables
in the language allow the generation of several correlated distributions.
To illustrate the advantages of using distribution view we present two applications: One
in Project Risk Management, compares the PERT method with Simulation alternative; The
other in Statistics, compares the Power of Randomization Test with the power of Student-t
Test , using the set of Marron-Wand distributions
relatório final
A intervenção a que este relatório se reporta teve como
principais objectivos: a) registar e interpretar a estratigrafia do
alçado poente da torre medieval; b) verificar a existência de
vestÃgios arqueológicos no subsolo; c) avaliar as condicionantes do
projecto de arquitectura previsto para este local
Geophysical prospection of antique structural traces from São Francisco (Évora) Royal Palace with the use of georradar and laser scanner.
In the place where currently there is the D. Manuel Palace, in Évora, will have been the Royal Palace of S. Francisco, one of the residences of the Portuguese monarchy between the sixteenth and seventeenth century. The building began
to decline in 1616 and has been adapted to
other occupations, abandoned and destroyed by re. Between this building and the market there are archaeological remains, discovered during the execution of urban works. The current building was the result of several changes on what’s left, the last one on the front of its facade, which were removed monumental stairs that there is photographic record. This work intends to show the existence of ancient palace remains, integrated into the structures that currently
exist within the research effective methods
of application of geophysical techniques in Archaeology. To realize the goal, it proceeded
to carry out geophysical prospecting with georadar, in areas adjacent to the palace, and with laser scanner, in order to integrate the results of georadar a three-dimensional representation of the current building. The results show the existence of structures that have corresponded to the palace staircase and remains consistent with the view that the palace would be extended to the side where there is the current market
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