An ant colony optimization algorithm for job shop scheduling problem

The nature has inspired several metaheuristics, outstanding among these is Ant Colony Optimization (ACO), which have proved to be very effective and efficient in problems of high complexity (NP-hard) in combinatorial optimization. This paper describes the implementation of an ACO model algorithm known as Elitist Ant System (EAS), applied to a combinatorial optimization problem called Job Shop Scheduling Problem (JSSP). We propose a method that seeks to reduce delays designating the operation immediately available, but considering the operations that lack little to be available and have a greater amount of pheromone. The performance of the algorithm was evaluated for problems of JSSP reference, comparing the quality of the solutions obtained regarding the best known solution of the most effective methods. The solutions were of good quality and obtained with a remarkable efficiency by having to make a very low number of objective function evaluations.Comment: http://www.airccse.org/journal/ijaia/current2013.htm

An ant colony optimization algorithm for job shop scheduling problem

The nature has inspired several metaheuristics, outstanding among these is Ant Colony Optimization (ACO), which have proved to be very effective and efficient in problems of high complexity (NP-hard) in combinatorial optimization. This paper describes the implementation of an ACO model algorithm known as Elitist Ant System (EAS), applied to a combinatorial optimization problem called Job Shop Scheduling Problem (JSSP). We propose a method that seeks to reduce delays designating the operation immediately available, but considering the operations that lack little to be available and have a greater amount of pheromone. The performance of the algorithm was evaluated for problems of JSSP reference, comparing the quality of the solutions obtained regarding the best known solution of the most effective methods. The solutions were of good quality and obtained with a remarkable efficiency by having to make a very low number of objective function evaluations.Sociedad Argentina de Informática e Investigación Operativ

An ant colony optimization algorithm for job shop scheduling problem

The nature has inspired several metaheuristics, outstanding among these is Ant Colony Optimization (ACO), which have proved to be very effective and efficient in problems of high complexity (NP-hard) in combinatorial optimization. This paper describes the implementation of an ACO model algorithm known as Elitist Ant System (EAS), applied to a combinatorial optimization problem called Job Shop Scheduling Problem (JSSP). We propose a method that seeks to reduce delays designating the operation immediately available, but considering the operations that lack little to be available and have a greater amount of pheromone. The performance of the algorithm was evaluated for problems of JSSP reference, comparing the quality of the solutions obtained regarding the best known solution of the most effective methods. The solutions were of good quality and obtained with a remarkable efficiency by having to make a very low number of objective function evaluations.Sociedad Argentina de Informática e Investigación Operativ

ABET Accreditation in Colombian Higher Education Institutions: Opportunities and Barriers

Accreditation is a contemporary issue in engineering education. There are varying opinions about the opportunities and barriers of this process within the Colombian context. This study compared the advantages and disadvantages of various experiences published in the literature about ABET accreditation. The findings show the ABET accreditation promotes the adoption and implementation of a continuous improvement system and quality culture in engineering education. Additionally, the continuous improvement process aligns the institutional mission, program educational objectives, curricula, and student outcomes. On the contrary, the main concern is the high cost associated with preparing and adapting programs to meet the ABET requirements. Accreditation takes time and effort to be meaningful, which can sometimes lead to increased workloads and time requirements, inadequate training, and lack of faculty commitment. The compilation of experiences with the ABET accreditation process is a significant contribution to engineering programs of public universities in Colombia seeking international accreditation.La acreditación es un tema contemporáneo en la educación superior, particularmente en ingeniería. Existen variedad de opiniones sobre las oportunidades y barreras para emprender este proceso dentro del contexto colombiano. Este estudio comparó las ventajas y desventajas de varias experiencias publicadas en la literatura sobre la acreditación internacional ABET. Dentro de la ventaja se identificaron la formalización de una cultura de mejora continua y calidad en la educación, como también, la integración entre la misión institucional, los objetivos educativos del programa, los planes de estudio y los resultados de aprendizaje. Por el contrario, dentro de las barreras se identificaron los altos costos asociados en el desarrollo de la acreditación, así como la adaptación de los programas a nivel curricular y reglamentario para cumplir con los requisitos. La recopilación de experiencias sobre el proceso de acreditación ABET es una contribución significativa a los programas de universidades públicas en Colombia que buscan la acreditación internacional

A comparison of edge-preserving approaches for differential interference contrast microscopy

In this paper we address the problem of estimating the phase from color images acquired with differential-interference-contrast microscopy. In particular, we consider the nonlinear and nonconvex optimization problem obtained by regularizing a least-squares-like discrepancy term with an edge-preserving functional, given by either the hypersurface potential or the total variation one. We investigate the analytical properties of the resulting objective functions, proving the existence of minimum points, and we propose effective optimization tools able to obtain in both the smooth and the nonsmooth case accurate reconstructions with a reduced computational demand

APLICACIÓN EN MATLAB PARA LA ESTIMACIÓN DE LA VARIABILIDAD DE LA PRESIÓN ARTERIAL

En el presente trabajo se abordan los conceptos fundamentales para la estimación de la variabilidad de la presión arterial a partir de registros digitalizados, empleando metodologías basadas en la implementación de métodos matemáticos para el procesamiento de la señal de presión arterial, con el objetivo de estimar los índices de variabilidad en el dominio del tiempo y frecuencia. En el dominio del tiempo se estimó la presión arterial máxima, mínima, promedio y desviación estándar, y en el dominio de la frecuencia, el índice de bajas frecuencias (LF, por sus siglas en ingles, low frequency), de altas frecuencias (HF, por sus siglas en ingles, high frequency), la relación entre bajas y altas frecuencias (LF/HF) y la potencia total (TP, por sus siglas en ingles, total power). Se desarrolló una aplicación usando el entorno de desarrollo integrado de Matlab, que implementa el algoritmo de Pan-Tompkins para la detección de los picos máximos de presión arterial y el método de Welch para la estimación de la densidad espectral de potencia. La herramienta se validó usando 20 señales correspondientes a 13 mujeres y 7 hombres entre los 12 y 87 años de edad y se comprobó la similitud entre los resultados obtenidos a partir de las estimaciones de variabilidad de la presión arterial arrojadas por la aplicación desarrollada, respecto a las estimaciones realizadas para los mismos índices usando el software WinCPRS (Absolute Aliens, Finland)

SISTEMA COMPUTACIONAL PARA LA DETECCIÓN DE GLÓBULOS ROJOS EN IMÁGENES MICROSCÓPICAS DE CÉLULAS SANGUÍNEAS

RESUMEN ANALÍTICOEl análisis de los glóbulos rojos es utilizado para la identificación y seguimiento de algunas enfermedades en el área de hematología e involucra dos procesos: el conteo y la inspección visual de las células. Con el ánimo de dar soporte al proceso de lectura visual que realiza el especialista, se propone un sistema computacional que permita realizar la detección de los glóbulos rojos, haciendo uso de la conceptualización matemática del Procesamiento Digital de Imágenes, a través del diseño e implementación de operadores bajo el paradigma de la Programación Orientada a Objetos. Este sistema cuenta con una interfaz gráfica agradable al usuario, con la cual se realizó un conjuntode pruebas de sensibilidad y especificidad del método de detección implementado. Se adquirieron 50 imágenes microscópicas a un aumento de 100x. Se obtuvo una sensibilidad de 84.78% y una especificidad de 92.89%.PALABRAS CLAVES: Glóbulos Rojos, Hematología, Procesamiento Digital de Imágenes, Sistema Computacional, OperadoresSOFTWARE TOOL FOR RED BLOOD CELLS DETECTION IN MICROSCOPIC BLOOD CELLS IMAGESANALYTICAL SUMMARYRed Blood Cells are analyzed for detection and monitoring of RBC related diseases, it involves two procedures: RBC counting and visual inspection of cells. Looking forward to support the process of visual analysis done by the specialist, it is proposed a computational system able to detect the red blood cells. It uses mathematical basis from Digital Signal Processing, through the design and implementation of operators under the Object Oriented Programming paradigm. The system has a friendly graphical user interface, with which were done a set of tests to measure sensibility and specificity of the implemented detection method. There were acquired 50 microscopic images at a zoom of 100x. Sensibility was 84.78% and specificity was 92.89%.KEYWORDS: Red Blood Cells, Hematology, Digital Image Processing, Computational System, Operator

Theoretical and experimental characterization of TiO2 thin films deposited at oblique angles

The microstructural features of amorphous TiO2 thin films grown by the electron beam physical vapour deposition technique at oblique angles have been experimentally and theoretically studied. The microstructural features of the deposited films were characterized by considering both, the column tilt angle and the increase of the column thickness with height. A Monte Carlo model of the film growth has been developed that takes into account surface shadowing, short-range interaction between the deposition species and the film surface, as well as the angular broadening of the deposition flux when arriving at the substrate. The good match between simulations and experimental results indicates the importance of these factors in the growth and microstructural development of thin films deposited at oblique angles.Ministerio de Innovación, MAT 2007-65764, CONSOLIDER INGENIO 2010-CSD2008-00023, PIE 200960I132Junta de Andalucía TEP2275, TEP5283, P07-FQM-03298, FQM-690

Growth regimes of porous gold thin films deposited by magnetron sputtering at oblique incidence: from compact to columnar microstructures

Growth regimes of gold thin films deposited by magnetron sputtering at oblique angles and low temperatures are studied from both theoretical and experimental points of view. Thin films were deposited in a broad range of experimental conditions by varying the substrate tilt angle and background pressure, and were analyzed by Field Emission Scanning Electron Microscopy (FESEM) and Grazing Incidence Small-Angle X-ray Scattering (GISAXS) techniques. Results indicate that the morphological features of the films strongly depend on the experimental conditions, but can be categorized within four generic microstructures, each of them defined by different bulk geometrical patterns and pore percolation depth and connectivity. With the help of a growth model, a microstructure phase diagram has been constructed where the main features of the films are depicted as a function of experimentally controllable quantities, finding a good agreement with the experimental results in all the studied cases.Junta de Andalucía P09-CTS- 5189, TEP5283, P10-FQM-6900Comunidad de Madríd S2009/MAT–1726Ministerio de Economía y Competitividad MAT2011-29194-C02-01, CSD2008-00023, MAT2008-06652, MAT2010-21228, MAT2010-1844