38 research outputs found

    Simulation-based optimization approach for vehicle allocation in a private transport service: A case study

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    Poor urban planning and traffic congestion lead to excessive delays in workers’ transit times and decrease their quality of life, especially in emerging countries. Several medium and large companies have a need to hire a transport service for their staff. In this type of transportation system, there is a heterogeneous fleet of vehicles, which are assigned to a set of predefined routes. However, the total transport delay can be even greater if the private transportation system is inefficient or not controlled. The approach proposed in this study seeks to optimize the private transport service by defining the best allocation of its fleet to its routes. A mathematical model is proposed to minimize user wait times. This approach is validated using real data obtained from a transport company in Co-lombia. The results demonstrate the quantitative benefits that can be achieved when the proposed approach is implemented, represented by a considerable reduction in user wait times

    Segmentation of Magnetic Resonance Imaging MRI using LS-SVM and Wavelet Multiresolution Analysis

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    Actualmente, las máquinas de soporte vectorial (SVM) se han convertido en una herramienta poderosa para resolver problemas de clasificación no lineal. Para la optimización de esta herramienta, se ha desarrollado una reformulación conocida como LS-SVM (máquina de soporte vectorial de mínimos cuadrados), la cual trabaja con un modelo de minimización basada en funciones y polinomios de Lagrange. Por lo tanto, este trabajo presenta un método para la segmentación de imágenes de resonancia magnética específicamente para estudiar la morfología de los pulmones y lograr la cuantificación de características relevantes en dichas imágenes usando SVM y LS-SVM. Adicionalmente a la técnica de clasificación, en este trabajo se usaron técnicas como: análisis Wavelet para eliminación de información no relevante (compresión), y algoritmos Splines, para interpolar la información encontrada y cuantificar las características, que se basaron en el reconocimiento de área, forma y estructuras anormales presentes en la zona pulmonar de dichas imágenes.Currently, support vector machines (SVM) have become a powerful tool to solve nonlinear classification problems. For the optimization of the tool, has developed a reformulation known as LS-SVM (Support Vector Machine least squares), which works with a model based on function minimization and Lagrange polynomials. Therefore, this paper presents a method for segmentation of magnetic resonance images specifically to study the morphology of the lungs and reach the quantification of relevant features in these images using SVM and LS-SVM. In addition to sorting technique in this work using techniques such as wavelet analysis to eliminate irrelevant information (compression) and Splines algorithms to interpolate the information found and quantify the characteristics, which in this work were based on the recognition area, shape and abnormal structures present in the lung of these images

    Lean-green improvement opportunities for sustainable manufacturing using water telemetry in agri-food industry.

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    Water has become a critical resource due to increased manufacturing activities. However, there is a lack of detailed information on water management and consumption by industries. In the recent bibliography, lean–green was established as a good approach for achieving sustainability in manufacturing industries, but few studies have aimed to achieve both operational and environmental improvements in water consumption. In this paper, we present a multi-case study in the agri-food industry in which water consumption in company activities is monitored, allowing them to improve their industrial processes based on lean–green practices, leading to a zero-waste strategy for this critical resource. The aim of this paper is to demonstrate the importance of having detailed knowledge regarding water consumption in order to discover, in a lean–green context, new improvement opportunities which could remain hidden by the current way of analysing consumption

    Procesamiento de Señales Provenientes del Habla Subvocal usando Wavelet Packet y Redes Neuronales

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    This paper presents the results obtained from the recording, processing and classification of words in the Spanish language by means of the analysis of subvocal speech signals. The processed database has six words (forward, backward, right, left, start and stop). In this work, the signals were sensed with surface electrodes placed on the surface of the throat and acquired with a sampling frequency of 50 kHz. The signal conditioning consisted in: the location of area of interest using energy analysis, and filtering using Discrete Wavelet Transform. Finally, the feature extraction was made in the time-frequency domain using Wavelet Packet and statistical techniques for windowing. The classification was carried out with a backpropagation neural network whose training was performed with 70% of the database obtained. The correct classification rate was 75%±2.Este artículo presenta los resultados obtenidos del registro, procesamiento, reconocimiento y clasificación de palabras del lenguaje español mediante el análisis de las señales de voz de habla subvocal. El trabajo en conjunto será en un futuro enfocado en aplicaciones de telecomunicaciones como: chat para sordo mudos. La base de datos procesada está conformada por seis palabras (adelante, atrás, derecha, izquierda, iniciar y parar). Las señales fueron sensadas con electrodos superficiales dispuestos en la superficie de la garganta y adquiridas con una frecuencia de muestreo de 50 Khz. El acondicionamiento de las señales consistió en: la ubicación de la zona de interés mediante análisis de energía, y el filtrado usando Transformada Wavelet Discreta. Finalmente, la extracción de características se hizo en el dominio del tiempo-frecuencia empleando Wavelet Packet y técnicas estadísticas por ventaneo. La clasificación se llevó a cabo con una Red Neuronal por Retropropagación cuyo entrenamiento se realizó con el 70% de la base de datos obtenida. El porcentaje de acierto encontrado fue de 75%±2

    Molecular and descriptive epidemiology of intestinal protozoan parasites of children and their pets in Cauca, Colombia: A cross-sectional study

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    Background: Parasitic infections, particularly those caused by protozoa, represent a considerable public health problem in developing countries. Blastocystis, Giardia duodenalis, Cryptosporidium spp. and the Entamoeba complex (Entamoeba histolytica, Entamoeba dispar and Entamoeba moshkovskii) are the most common etiological causes of intestinal parasitic infections. Methods: We carried out a descriptive cross-sectional study in school-age children attending a daycare institution in commune eight of Popayán, Cauca (Southwest Colombia). A total of 266 fecal samples were collected (258 from children and eight from pets). Blastocystis, G. duodenalis, Cryptosporidium spp. and the Entamoeba complex were identified by microscopy, quantitative real-time PCR (qPCR) and conventional PCR. The concordance of qPCR and microscopy was assessed using the Kappa index. Molecular characterization was conducted to identify Blastocystis subtypes (18S), G. duodenalis assemblages (tpi and gdh) and Cryptosporidium species/subtypes (18S and GP60). Potential associations between intestinal parasitism and sociodemographic factors were examined using bivariate analyses. Results: A total of 258 fecal samples from children were analyzed by microscopy and 255 samples were analyzed by qPCR. The prevalence of Blastocystis was between 25.19% (microscopy) and 39.22% (qPCR), that of G. duodenalis was between 8.14% (microscopy) and 10.59% (qPCR), that of Cryptosporidium spp. was estimated at 9.8% (qPCR), and that of the Entamoeba complex was between 0.39% (conventional PCR) and 0.78% (microscopy). The concordance between microscopy and qPCR was very low. Blastocystis ST1 (alleles 4, 8, and 80), ST2 (alleles 11, 12, and 15), ST3 (alleles 31, 34, 36, 38,57, and 151), and ST4 (alleles 42 and 91), G. duodenalis assemblages AII, BIII, BIV and D, C. parvum subtype IIa and C. hominis subtype IbA9G3R2 were identified. The only identified member of the Entamoeba complex corresponded to E. histolytica. No statistically significant association was identified between parasitic infection and any sociodemographic variable. Conclusion: This study revealed the usefulness of molecular methods to depict the transmission dynamics of parasitic protozoa in southwest Colombia. The presence of some of these protozoa in domestic animals may be involved in their transmission. © 2019 The Author(s)

    The Chemical Evolution Carousel of Spiral Galaxies : Azimuthal Variations of Oxygen Abundance in NGC1365

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    19 pages, 13 figures. Accepted to ApJThe spatial distribution of oxygen in the interstellar medium of galaxies is the key to understanding how efficiently metals that are synthesized in massive stars can be redistributed across a galaxy. We present here a case study in the nearby spiral galaxy NGC1365 using 3D optical data obtained in the TYPHOON Program. We find systematic azimuthal variations of the HII region oxygen abundance imprinted on a negative radial gradient. The 0.2 dex azimuthal variations occur over a wide radial range of 0.3 to 0.7 R25 and peak at the two spiral arms in NGC1365. We show that the azimuthal variations can be explained by two physical processes: gas undergoes localized, sub-kpc scale self-enrichment when orbiting in the inter-arm region, and experiences efficient, kpc scale mixing-induced dilution when spiral density waves pass through. We construct a simple chemical evolution model to quantitatively test this picture and find that our toy model can reproduce the observations. This result suggests that the observed abundance variations in NGC1365 are a snapshot of the dynamical local enrichment of oxygen modulated by spiral-driven, periodic mixing and dilution.Peer reviewedFinal Published versio

    A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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    Contributions of mean and shape of blood pressure distribution to worldwide trends and variations in raised blood pressure: A pooled analysis of 1018 population-based measurement studies with 88.6 million participants

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    © The Author(s) 2018. Background: Change in the prevalence of raised blood pressure could be due to both shifts in the entire distribution of blood pressure (representing the combined effects of public health interventions and secular trends) and changes in its high-blood-pressure tail (representing successful clinical interventions to control blood pressure in the hypertensive population). Our aim was to quantify the contributions of these two phenomena to the worldwide trends in the prevalence of raised blood pressure. Methods: We pooled 1018 population-based studies with blood pressure measurements on 88.6 million participants from 1985 to 2016. We first calculated mean systolic blood pressure (SBP), mean diastolic blood pressure (DBP) and prevalence of raised blood pressure by sex and 10-year age group from 20-29 years to 70-79 years in each study, taking into account complex survey design and survey sample weights, where relevant. We used a linear mixed effect model to quantify the association between (probittransformed) prevalence of raised blood pressure and age-group- and sex-specific mean blood pressure. We calculated the contributions of change in mean SBP and DBP, and of change in the prevalence-mean association, to the change in prevalence of raised blood pressure. Results: In 2005-16, at the same level of population mean SBP and DBP, men and women in South Asia and in Central Asia, the Middle East and North Africa would have the highest prevalence of raised blood pressure, and men and women in the highincome Asia Pacific and high-income Western regions would have the lowest. In most region-sex-age groups where the prevalence of raised blood pressure declined, one half or more of the decline was due to the decline in mean blood pressure. Where prevalence of raised blood pressure has increased, the change was entirely driven by increasing mean blood pressure, offset partly by the change in the prevalence-mean association. Conclusions: Change in mean blood pressure is the main driver of the worldwide change in the prevalence of raised blood pressure, but change in the high-blood-pressure tail of the distribution has also contributed to the change in prevalence, especially in older age groups

    A century of trends in adult human height

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    A century of trends in adult human height

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