Speeding up the cyclic edit distance using LAESA with early abandon

The cyclic edit distance between two strings is the minimum edit distance between one of this strings and every possible cyclic shift of the other. This can be useful, for example, in image analysis where strings describe the contour of shapes or in computational biology for classifying circular permuted proteins or circular DNA/RNA molecules. The cyclic edit distance can be computed in O(mnlog m) time, however, in real recognition tasks this is a high computational cost because of the size of databases. A method to reduce the number of comparisons and avoid an exhaustive search is convenient. In this work, we present a new algorithm based on a modification of LAESA (linear approximating and eliminating search algorithm) for applying pruning in the computation of distances. It is an efficient procedure for classification and retrieval of cyclic strings. Experimental results show that our proposal considerably outperforms LAESAWork partially supported by the Spanish Government (TIN2010-18958), and the Generalitat Valenciana (PROMETEOII/2014/062)

On the Dynamic Time Warping of Cyclic Sequences for Shape Retrieval

In the last years, in shape retrieval, methods based on Dynamic Time Warping and sequences where each point of the contour is represented by elements of several dimensions have had a significant presence. In this approach each point of the closed contour contains information with respect to the other ones, this global information is very discriminant. The current state-of-the-art shape retrieval is based on the analysis of these distances to learn better ones. These methods are robust to noise and invariant to transformations, but, they obtain the invariance to the starting point with a brute force cyclic alignment which has a high computational time. In this work, we present the Cyclic Dynamic Time Warping. It can obtain the cyclic alignment in O(n2 log n) time, where n is the size of both sequences. Experimental results show that our proposal is a better alternative than the brute force cyclic alignment and other heuristics for obtaining this invariance

On hidden Markov models and cyclic strings for shape recognition

Shape descriptions and the corresponding matching techniques must be robust to noise and invariant to transformations for their use in recognition tasks. Most transformations are relatively easy to handle when contours are represented by strings. However, starting point invariance is difficult to achieve. One interesting possibility is the use of cyclic strings, which are strings that have no starting and final points. We propose new methodologies to use Hidden Markov Models to classify contours represented by cyclic strings. Experimental results show that our proposals outperform other methods in the literature

Highest Plasma Phenylalanine Levels in (Very) Premature Infants on Intravenous Feeding; A Need for Concern

Objective. To analyse the association in newborns between blood levels of phenylalanine and feeding method and gestational age. Study Design. This observational, cross-sectional study included a sample of 11,829 infants between 2008 and 2013 in a Spanish region. Data were recorded on phenylalanine values, feeding method [breast, formula, mixed (breast plus formula), or partial or fully intravenous feeding], gestational age in weeks (<32, 32–37, ≥37), gender and days since birth at the moment of blood collection. Outcomes were [phenylalanine] and [phenylalanine] ≥95th percentile. Associations were analysed using multivariate models [linear (means difference) and logistic regression (adjusted odds ratios)]. Results. Higher phenylalanine values were associated with lower gestational age (p<0.001) and with intravenous feeding (p<0.001). Conclusion. The degree of prematurity and intravenous feeding influenced the plasma concentration of phenylalanine in the newborn. Caution should be taken in [phenylalanine] for newborns with intravenous feeding, monitoring them carefully. Very preterm infants given the recommended amount of amino acids should also be strictly monitored. These findings should be taken into consideration and call for adapting the amounts to the needs of the infant

Impacts of Use and Abuse of Nature in Catalonia with Proposals for Sustainable Management

This paper provides an overview of the last 40 years of use, and in many cases abuse, of the natural resources in Catalonia, a country that is representative of European countries in general, and especially those in the Mediterranean region. It analyses the use of natural resources made by mining, agriculture, livestock, logging, fishing, nature tourism, and energy production and consumption. This use results in an ecological footprint, i.e., the productive land and sea surface required to generate the consumed resources and absorb the resulting waste, which is about seven times the amount available, a very high number but very similar to other European countries. This overexploitation of natural resources has a huge impact on land and its different forms of cover, air, and water. For the last 25 years, forests and urban areas have each gained almost 3% more of the territory at the expense of agricultural land; those municipalities bordering the sea have increased their number of inhabitants and activity, and although they only occupy 6.7% of the total surface area, they account for 43.3% of the population; air quality has stabilized since the turn of the century, and there has been some improvement in the state of aquatic ecosystems, but still only 36% are in good condition, while the remainder have suffered morphological changes and different forms of nonpoint source pollution; meanwhile the biodiversity of flora and fauna remains still under threat. Environmental policies do not go far enough so there is a need for revision of the legislation related to environmental impact and the protection of natural areas, flora, and fauna. The promotion of environmental research must be accompanied by environmental education to foster a society which is Land 2021, 10, 144 3 of 53 more knowledgeable, has more control and influence over the decisions that deeply affect it. Indeed, nature conservation goes hand in hand with other social and economic challenges that require a more sustainable vision. Today’s problems with nature derive from the current economic model, which is environmentally unsustainable in that it does not take into account environmental impacts. Lastly, we propose a series of reasonable and feasible priority measures and actions related to each use made of the country’s natural resources, to the impacts they have had, and to their management, in the hope that these can contribute to improving the conservation and management of the environment and biodiversity and move towards sustainability.info:eu-repo/semantics/publishedVersio

Alineamiento de cadenas cí­clicas en el reconocimiento de formas bidimensionales

Cuando queremos comparar dos formas bidimensionales utilizando sus contornos, suele presentarse un problema importante: la invarianza al punto inicial en su codificación como secuencia. Aunque existen métodos heurísticos para conseguir un buen punto de inicio que funcionan en ciertos contextos, si queremos una solución genérica, la única manera de conseguir esta invarianza es midiendo distancias con todos los posibles puntos iniciales, es decir, utilizando el alineamiento por fuerza bruta con todo posible inicio de la secuencia del contorno. De aquí surge el concepto de cadena cíclica. Así, medir una distancia entre dos cadenas cíclicas sería lo mismo que medir una distancia entre todos los posibles puntos iniciales de las dos cadenas. Esta comparación es muy costosa computacionalmente y el trabajo de la literatura se ha orientado sobre todo a reducir este coste.Existe mucho trabajo, a este respecto, en el dominio de las distancias de edición. Sin embargo, con otras técnicas, como son el alineamiento temporal no lineal (en inglés, Dynamic Time Warping) o los modelos ocultos de Markov (más tolerantes al ruido y otras deformaciones), no se ha profundizado demasiado con las cadenas cíclicas. Las aportaciones de esta tesis, van orientadas en esta dirección.Con el alineamiento temporal no lineal (ATNL), hemos desarrollado un algoritmo eficiente para el cálculo del ATNL cíclico. Hemos planteado también diversas alternativas para acelerar el cálculo del ATNL cíclico en tareas de reconocimiento. En primer lugar, un heurístico para evitar el cálculo cíclico, en el caso de que tengamos categorías etiquetadas. En segundo lugar, un método óptimo para acelerar el cálculo cíclico, utilizando una cota inferior basada en un pseudo-alineamiento que aproxima la distancia cíclica. Finalmente, aportamos soluciones basadas en AESA (Approximating and Eliminating Search Algorithm) y una mejora al algoritmo LAESA (Linear AESA).Con los modelos ocultos de Markov, estudiamos la topología lineal en el reconocimiento de contornos y desarrollamos extensiones cíclicas para los algoritmos de Viterbi (reconocimiento y entrenamiento) y Baum-Welch (entrenamiento)

Predicted probability of atypical phenylalanine (≥95th Percentile) according to gestational age and feeding method in newborns.

<p>Phe, phenylalanine; w, weeks.</p