RECOGNITION OF HUMAN MOVEMENT PATTERNS

INTRODUCTION - Since a few years ago computer science means an important sup port to biomechanical analysis. Whenever a lot of calculations are to be made, and the value of different parameters like mechanical variables are needed, the advantages of using computers are clear. However a bottleneck is present in data acquisition process for cinematic analysis from video sequence. Traditionally this task is performed like a manual process: user of computer systems must mark, for each frame, some articular points (about 20-21 ) by means of an optical pencil or using a mouse on the computer display once image has been digitalized. This is a routinary task and takes a lot of time. For example, for three seconds of movement, we probably need to process about 150 frames and, for each of them, to perform a digitalizing process. Recently new approaches are used to allow an automatic recognition. These approaches are based on the use of body optical sensors. Recognition process is easier because we only see several single points in the screen (under special environment conditions). However, these approaches are no applicable in real situations (i.e. competitions) which are the most interesting moments for analysis. What we propose here is an attempt to make an automatic system for data acquisition process from video sequences in sport environments and, as a general rule, for the analysis of human movement. We must take into account that the complexity of recognition process is lowered if we are working into a very narrow domain, like cyclic movements with 2D analysis (i.e. path of legs in some kinds of running). Nevertheless, our approach can be transferred to movements with 3D analysis if tridimensional reconstruction from human shapes has been performed. The process that our system will perform on each frame includes: . Digital image pre-processing, Edge sharpening, contrast adjust and filling of areas of interest. . If results are on satisfactoy (e.g. incomplete shapes), an Artificial Neural Network is used in order to predict total pattern, using previous frames or information available in a sportmen customized database containing antrophometric data and cinematic pattern of movement. . Last step is an intelligent matching between articular segments included in database (invariables botn with a 3D analysis and with a 2D analysis under specific features mentioned above) and human shapes obtained from previous steps. RESULTS - First phase relating to image recognition in laboratory conditions (high contrast) has been performed and the difference between manual articular coordenates and automatic acquisition was about zero-two units. CONCLUSION - The system we propose can help to biomechanics to reduce a lot the time destinated to perform data acquisition. Several hours would be changed to some minutes without human assist. REFERENCES R. J. Schalkoff, (1988) Digital lmage Processing and Computer Vision. John Wiley and Sons Inc. L.J. Galbiati, (1988) Machine Vision and Digital lmage Processing Fundamentals. Prentice-Hall International. C.H. Chen, (1993) Handbook of Pattern Recognition and Computer Vision. World Scientific

"El café tiene cafeína y nos despierta, nos da energía" : concepciones sobre la energía química, una buena razón para poner de acuerdo a los profesores de Física y Química y ciencias Naturales

A research was carried on students' conceptions about chemical energy. The experimental sample were students from primary level to university. Word association tasks and a paper and pencil question were used as instruments for collecting data. The test revealed that some students share certain alternative conceptions about chemical energy, and that most of them use ideas about chemical energy in a similar way to what people without formal instruction in this issue would do. Some implications for science teaching-learning are suggested

Detritic deposits of periglacial origin under coluvial organic soil on a slope in Serra da Loba. (Galicia. Spain): characterization and genesis

[Resumen] En ciertas posiciones de las partes media e inferior de la ladera aparece bajo el suelo orgánico un material detrítico muy fragmentado y ordenado en lechos estratificados. Se estudian dos perfiles con estas características, se canografía su extensión en la ladera, y se interpreta su génesis. Estos derrubios tienen poca fracci6n fina entre ellos, son bastante frescos, yaparecen ordenados según la pendiente y dispuestos en lechos en los que se alternan fragmentos de pequeño tamaño con otros más gruesos con más escaso contenido en fracción fina. Los estudios morfológicos y granulométricos revelan claras discontinuidades en los perfiles, así como una baja clasificaci6n de este material detrítico. La composición mineralógica es menos reveladora por su escasa evolución, prácticamente la heredada del material de partida, con predominio de minerales poco alterables. Se hace una correspondencia estratigráfica de episodios de deposici6n en ambos perfiles y se interpreta el origen de este material detrítico como ligado al accionamiento periglaciar. La localizaci6n en la ladera de estos depósitos y su potencia están relacionados con el menor espesor de las líneas de piedras, indicativas de procesos de erosión posterior. Sin embargo estos depósitos están ausentes en las partes más bajas de la ladera que, en cambio, muestran ser las más propicias a la deposición, ya que presentan un mayor engrosamiento de los horizontes orgánicos de acumulaci6n y en ellas no aparecen indicios erosivos. Esta ausencia se interpreta por ser también estas zonas, bajas y abrigadas, las que podrían ser más favorables a una mayor cobertura vegetal en las condiciones periglaciares, que impediría la deposición de los derrubios.[Abstract] Stratified beds of highly fragmented detritic material under organic soil occur on medium and low parts ofthe slope. Two profiles with these features are studied, their extent on the slope is mapped and their genesis interpreted. Debris are quite fresh, with little fine fraction between them; they are arranged according to the slope and consist of alternating beds of little size fragments and others coarser and poor in fine fraction. Morphological and granulometric studies reveal clear discontinuities in the profiles and a poor soning of the detritic Ínaterials. Mineralogical composition is less meaningful because of its little evolution, almost inherited from parent material, with a predominance of hardly weatherable minerals. A stratigraphic correspondence is established of deposition episodes between both profiles, and the origin of the detritic material is related to periglacial dynamics. The position of these deposits on the slope and their thickness are inversely related to the thickness of stonelines which are indicative of subsequent erosive processes. Detritic deposits are absent in the lowest part of the slope, which on the other hand appear to be the most favourable to deposition as showed by the greatest thickness of organic horizons of accumulation, and the no occurrence of erosive signs. This absence is' interpreted as being caused by the presence of a more extensive vegetal cover, under periglacial conditions, in the lowest and more protected slope, so preventing debris deposition

Stochastic energy-cascade model for 1+1 dimensional fully developed turbulence

Geometrical random multiplicative cascade processes are often used to model positive-valued multifractal fields such as the energy dissipation in fully developed turbulence. We propose a dynamical generalization describing the energy dissipation in terms of a continuous and homogeneous stochastic field in one space and one time dimension. In the model, correlations originate in the overlap of the respective spacetime histories of field amplitudes. The theoretical two- and three-point correlation functions are found to be in good agreement with their equal-time counterparts extracted from wind tunnel turbulent shear flow data

Gamma rays from microquasars Cygnus X-1 and Cygnus X-3

Gamma-ray observations of microquasars at high and very-high energies can provide valuable information of the acceleration processes inside the jets, the jet-environment interaction and the disk-jet coupling. Two high-mass microquasars have been deeply studied to shed light on these aspects: Cygnus X-1 and Cygnus X-3. Both systems display the canonical hard and soft X-ray spectral states of black hole transients, where the radiation is dominated by non-thermal emission from the corona and jets and by thermal emission from the disk, respectively. Here, we report on the detection of Cygnus X-1 above 60 MeV using 7.5 yr of Pass8 Fermi-LAT data, correlated with the hard X-ray state. A hint of orbital flux modulation was also found, as the source is only detected in phases around the compact object superior conjunction. We conclude that the high-energy gamma-ray emission from Cygnus X-1 is most likely associated with jets and its detection allow us to constrain the production site. Moreover, we include in the discussion the final results of a MAGIC long-term campaign on Cygnus X-1 that reaches almost 100 hr of observations at different X-ray states. On the other hand, during summer 2016, Cygnus X-3 underwent a flaring activity period in radio and high-energy gamma rays, similar to the one that led to its detection in the high-energy regime in 2009. MAGIC performed comprehensive follow-up observations for a total of about 70 hr. We discuss our results in a multi-wavelength context.Comment: Proceedings of the 35th International Cosmic Ray Conference (ICRC 2017), Bexco, Busan, Korea (arXiv:1708.05153

Marie Anne Paulze Lavoisier: unha descoñecida científica

[RESUMO] A contribución das mulleres á creación científica ao longo da historia da Humanidade non parece importante se consideramos o pouco que aparecen nos libros de texto; deste xeito, o alumnado non advertirá a existencia de mulleres que fixeron ou elaboraron leis ou teorías nas ciencias. Personaxes como: Hipatia de Alejandría, Hildegarda de Birgen, Caroline Herschel, María Cunitz, Marie Orr Evershed, Augusta Ada Byron, María Montagu, María Agnesi, Sophía Germain, Sonya Kovalevski, María Goeppter Mayer, Rosalin Franklin, Lise Meitner,..., son descoñecidas do gran público. Incluso aquelas que resultan ser coñecidas, como Irene ou Marie Curie, tampouco foron dabondo valoradas. Para recuperar estas mulleres científicas do silencio e do esquecemento e facelas visibles debemos sacar á luz as súas achegas. Este é o caso da protagonista da nosa comunicación. Marie-Anne Pierrette Paulze, que nos libros aparece como a esposa de Lavoisier, pero non como unha persoa con coñecementos científicos profundos como esperamos amosar. Presentamos as súas no mundo da química, que practicaba xunto ao seu home, e a todos cantos científicos formaban o chamado grupo do Arsenal

Lognormal scale invariant random measures

In this article, we consider the continuous analog of the celebrated Mandelbrot star equation with lognormal weights. Mandelbrot introduced this equation to characterize the law of multiplicative cascades. We show existence and uniqueness of measures satisfying the aforementioned continuous equation; these measures fall under the scope of the Gaussian multiplicative chaos theory developed by J.P. Kahane in 1985 (or possibly extensions of this theory). As a by product, we also obtain an explicit characterization of the covariance structure of these measures. We also prove that qualitative properties such as long-range independence or isotropy can be read off the equation.Comment: 31 pages; Probability Theory and Related Fields (2012) electronic versio

Wavelets techniques for pointwise anti-Holderian irregularity

In this paper, we introduce a notion of weak pointwise Holder regularity, starting from the de nition of the pointwise anti-Holder irregularity. Using this concept, a weak spectrum of singularities can be de ned as for the usual pointwise Holder regularity. We build a class of wavelet series satisfying the multifractal formalism and thus show the optimality of the upper bound. We also show that the weak spectrum of singularities is disconnected from the casual one (denoted here strong spectrum of singularities) by exhibiting a multifractal function made of Davenport series whose weak spectrum di ers from the strong one