Papers by Alfonso Florez Ortega
Proceedings of the 9th annual conference on Genetic and evolutionary computation - GECCO '07, 2007
Proceedings of the conference on Designing the future - APL '96, 1996
Fractals can be represented by means of Lsystems (Development Grammars), together with a graphic ... more Fractals can be represented by means of Lsystems (Development Grammars), together with a graphic interpretation.
ACM SIGAPL APL Quote Quad, 1996
Fractals can be represented by means of Lsystems (Development Grammars), together with a graphic ... more Fractals can be represented by means of Lsystems (Development Grammars), together with a graphic interpretation.
2007 IEEE Congress on Evolutionary Computation, 2007
Recent large scale experiments have shown that the Normalized Information Distance, an algorithmi... more Recent large scale experiments have shown that the Normalized Information Distance, an algorithmic information measure, is among the best similarity metrics for melody classification. This paper proposes the use of this distance as a fitness function which may be used by genetic algorithms to automatically generate music in a given pre-defined style. The minimization of this distance of the generated music to a set of musical guides makes it possible to obtain computer-generated music which recalls the style of a certain human author. The recombination operator plays an important role in this problem and thus several variations are tested to fine tune the genetic algorithm for this application. The superiority of the relative pitch envelope over other music parameters, such as the lengths of the notes, brought us to develop a simplified algorithm that nevertheless obtains interesting results.
Journal of Lightwave Technology, 2000
A hollow-core photonic bandgap (PBG) fiber sensing configuration for optical absorption spectrosc... more A hollow-core photonic bandgap (PBG) fiber sensing configuration for optical absorption spectroscopy of multiple-component gas samples absent of a vacuum environment is presented. Pressure-driven sensor response times that are shorter in duration compared to diffusion-limited filling times for fiber lengths 1 m are reported. Reduced filling times that approach the subminute regime are possible for a 2 meter length of commercially available PBG fiber with a 12.5 micron core diameter at a pressure 15 Psi. The spectroscopy measurements were limited to the near-IR region for sample gases that include acetylene and carbon dioxide. Using the techniques presented, the detection of concentrations 100 ppm for acetylene gas at pressures 15 Psi is pos-
IEEE Transactions on Information Theory, 2000
This correspondence studies the influence of noise on the normalized compression distance (NCD), ... more This correspondence studies the influence of noise on the normalized compression distance (NCD), a measure based on the use of compressors to compute the degree of similarity of two files. This influence is approximated by a first order differential equation which gives rise to a complex effect, which explains the fact that the NCD may give values greater than 1, observed by other authors. The model is tested experimentally with good adjustment. Finally, the influence of noise on the clustering of files of different types is explored, finding that the NCD performs well even in the presence of quite high noise levels.
Communications in Information and Systems, 2005
Using the mathematical background for algorithmic complexity developed by Kolmogorov in the sixti... more Using the mathematical background for algorithmic complexity developed by Kolmogorov in the sixties, Cilibrasi and Vitanyi have designed a similarity distance named normalized compression distance applicable to the clustering of objects of any kind, such as music, texts or gene sequences. The normalized compression distance is a quasi-universal normalized admissible distance under certain conditions. This paper shows that the compressors used to compute the normalized compression distance are not idempotent in some cases, being strongly skewed with the size of the objects and window size, and therefore causing a deviation in the identity property of the distance if we don't take care that the objects to be compressed fit the windows. The relationship underlying the precision of the distance and the size of the objects has been analyzed for several well-known compressors, and specially in depth for three cases, bzip2, gzip and PPMZ which are examples of the three main types of compressors: block-sorting, Lempel-Ziv, and statistic.
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Papers by Alfonso Florez Ortega