Decision-making Tools and Memetic Algorithms in Management and Linear Programming Problems

Operational Research uses a set of tools based on scientific research principles to achieve rational and meaningful management decisions. This article tries to give solution to a highly complex Linear Programming problem by using Simplex method, Solver and a hybrid prototype which combines the theories of Genetic Algorithms with a new local search heuristic technique. Hybridization of these two techniques is becoming known as Memetic Algorithm. Additionally, this article tries to present different techniques to support management decision-making, with the intention of being used increasingly in the business environment sustaining, thus, decisions by mathematics or artificial intelligence and not only by experience.quantitative management; quantitative methods; decision-making; linear programming; operational research; heuristics; hybrid methods; memetic algorithms.

Ultrasonographic scoring system for superficial digital flexor tendon injuries in horses: intra- and inter-rater variability

Superficial digital flexor tendon (SDFT) tendinopathy is an important musculoskeletal problem in horses. The study objective was to validate an ultrasonographic scoring system for SDFT injuries. Ultrasonographic images from 14 Thoroughbred racehorses with SDFT lesions (seven core; seven diffuse) and two controls were blindly assessed by five clinicians on two occasions. Ultrasonographic parameters evaluated were: type and extent of the injury, location, echogenicity, cross-sectional area and longitudinal fibre pattern of the maximal injury zone (MIZ). Inter-rater variability and intra-rater reliability were assessed using Kendall’s coefficient of concordance (KC) and Lin’s concordance correlation coefficient (LC), respectively. Type of injury (core vs. diffuse) had perfect inter/intra-rater agreement. Cases with core lesions had very strong inter-rater agreement (KC ≥0.74, P<0.001) and intra-rater reliability (LC ≥0.73) for all parameters apart from echogenicity. Cases with diffuse lesions had strong inter-rater agreement (KC ≥0.62) for all parameters, but weak agreement for echogenicity (KC=0.22); intra-rater reliability was excellent for MIZ location and fibre pattern (LC ≥0.82), and moderate (LC ≥0.58) for cross-sectional area and number of zones affected. This scoring system was reliable and repeatable for all parameters, except for echogenicity. A validated scoring system will facilitate reliable recording of SDFT injuries and inter-study meta-analyses

El proyecto Flying Challenge, una experiencia de interconexión universidad-empresa utilizando mentoría entre iguales

Congreso Universitario de Innovación Educativa En las Enseñanzas Técnicas, CUIEET (26º. 2018. Gijón

Alimentación saludable de la población argentina y elección de alimentos vinculados al estilo de vida de la población urbana de Mar del Plata

El objetivo es analizar el grado de diversificación de la dieta de la población, los hábitos y factores que afectan las elecciones de alimentos saludables. Se tendrán en cuenta atributos y riesgos percibidos al consumir alimentos y diferencias entre grupos de individuos según características demográficas y socio-económicas. Se analizará la participación de los gastos en alimentos "saludables" en la estructura de alimentos a nivel nacional y de nuestra ciudad. Se identificaran grupos de individuos según hábitos saludables en la Ciudad de Mar del Plata y se compararán con las de los de la Provincia de Buenos Aires y resto del país. Se utilizaran datos de la Encuesta Nacional de Gastos de los Hogares (ENGHO) del INDEC 2012-2013. Se complementará con el análisis de la Encuesta Nacional de Factores de Riesgo (ENFR) 2013. La Base de datos 2014 para Mar del Plata tiene 505 individuos seleccionados con un muestreo probabilístico proporcional por sexo y edad de una población o universo de 457.537personas que conforman la población marplatense de 18 años y más. Esta encuesta a consumidores contiene información sobre Alimentación saludable, Consumo de verduras frescas, Hábitos saludables, Información y riesgos asociados al consumo de alimentos y un bloque final que contiene Información demográfica y socio-económica. Los métodos estadísticos-econométricos a aplicar incluyen el análisis Multivariado, Discriminante y la Estimación de modelos logísticos de elecciones de consumo.The objective is to analyze the degree of diversification of the diet of the population, habits and factors that affect food healthy choices. Attributes and perceived risks to consume foods and differences among groups of individuals will be taken into account according to demographic and socioeconomics characteristics. It will analyze the participation of expenditures on healthy food in the structure of consumption of food at national level and in our city. Groups of individuals will be identified according to healthy habits in the city of Mar del Plata and they will be compared with those of the Province of Buenos Aires and the rest of the country. Data from the national survey of household expenditure of INDEC 2012-2013 will be complemented with the National Survey of Risk Factors (ENFR). The database 2014 for Mar del Plata contains 505 individuals selected with a probabilistic proportional sampling by sex and age of a population of 457.537 individuals of 18 years old and more. The consumer's survey contains information about healthy eating, consumption of fresh vegetables, healthy habits, information and risks associated with consumption of food and demographic and socio-economic information. The statistics and econometrics tools to apply will be multivariate, discriminant analysis and the estimation of logistic models of consumer's choice.Fil: Rodríguez, Elsa Mirta M. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Lupín, Beatriz. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Alfonso, Néstor Manuel. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Iturrarte, Darío. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Rodríguez, Julieta A. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Alzola, Agustina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina

Scattering images from autocorrelation functions of P-wave seismic velocity images : the case of Tenerife Island (Canary Islands, Spain)

We thank Edoardo Del Pezzo for the valuable idea of this paper and suggestions regarding the methodology. J. Prudencio is partially supported by NSF1521855 Hazard SEES project. This paper has been partially supported by the Spanish project KNOWAVES (TEC2015-68752-R (MINECO/FEDER)), the European project MED-SUV funded by the European Union’s Seventh Framework Program for research, technological development and demonstration under Grant Agreement No 308665, and by the Regional project ‘Grupo de Investigación en Geofísica y Sismología de la Junta de Andalucía, RNM104’.Peer reviewedPostprin

First-fault detection in DC distribution with IT grounding based on Sliding Discrete Fourier-Transform

Since dc distribution minimizes the number of power conversion stages, it lowers the overall cost, power losses, and weight of a power system. Critical systems use IT grounding because it is tolerant to the first-fault. Hence, this is an attractive option for hybrid electric aircraft (HEA), which combines gas engines with electric motors driven by power electronic converters. This letter proposes an accurate implementation for the procedure of first-fault detection with IT grounding. The ac component injection along with the sliding discrete Fourier transform (SDFT) is used to estimate the fault impedance. The procedure is very accurate due to the heavy filtering of the implicit moving average filter. Further computation savings are obtained by using the double look-up tables, and the Goertzel algorithm for the SDFT. Results are validated by simulations and experiments

Design of modular, CFRP-encased electrical power systems for more-electric aircraft applications

Decarbonisation of aviation is directly supported by the twin trends of electrification of aircraft, and use of light-weight, carbon fibre reinforced polymer (CFRP) aircraft structures. The concept of creating a modularised electrical power system (EPS), with EPS equipment encased in CFRP opens up new design opportunities for electrification of aircraft systems; reduced weight and volume, reduced time out-of-service due to maintenance. Such systems necessitate an understanding of how electrical and structural systems interact, and the design boundary between the CFRP providing combined electrical and structural functionality, versus CFRP with a purely structural functionality, with a separate electrical system encased in CFRP. A power electronic converter (PEC) is an enabling technology for the more-electric aircraft EPS. The paper identifies the key design interdependencies, trades and integrated systems design levers for design of a CFRP casing for a PEC module through a conceptual case study. This includes the capture of high and low frequency electrical functionality, thermal management requirements, and their interdependencies with the topology and functional role of the PEC and the wider EPS architecture. This knowledge is combined to present a design methodology for the design of composite casings for PEC in modularised, on-board electrical power systems

Algoritmos meméticos en problemas de investigación operativa

En este artículo se plantea la resolución de un problema de Investigación Operativa utilizando PHPSimplex (herramienta online de resolución de problemas de optimización utilizando el método Simplex), Solver de Microsoft Excel y un prototipo híbrido que combina las teorías de los Algoritmos Genéticos con una técnica heurística de búsqueda local. La hibridación de estas dos técnicas es conocida como Algoritmo Memético. Este prototipo será capaz de resolver problemas de Optimización con función de maximización o minimización conocida, superando las restricciones que se planteen. Los tres métodos conseguirán buenos resultados ante problemas sencillos de Investigación Operativa, sin embargo, se propone otro problema en el cual el Algoritmo Memético y la herramienta Solver de Microsoft Excel, alcanzarán la solución óptima. La resolución del problema utilizando PHPSimplex resultará inviable. El objetivo, además de resolver el problema propuesto, es comparar cómo se comportan los tres métodos anteriormente citados ante el problema y cómo afrontan las dificultades que éste presenta. Además, este artículo pretende dar a conocer diferentes técnicas de apoyo a la toma de decisiones, con la intención de que se utilicen cada vez más en el entorno empresarial sustentando, de esta manera, las decisiones mediante la matemática o la Inteligencia Artificial y no basándose únicamente en la experiencia.KUTXA; Vicerrectorado de Campus de Gipuzkoa de la UPV/EH

Adaptive Smith predictor for enhanced stability of power hardware-in-the-loop setups

The stability and accuracy of power hardware-in-the-loop (PHIL) setups are sensitive to and deteriorated by the dynamics and non-ideal characteristics of their power interfaces, such as time delay, noise perturbation, and signal distortion. In this paper, a compensation scheme comprising a Smith predictor compensator is proposed to mitigate the impact of time delay on PHIL stability. Furthermore, an online system impedance identification technique is leveraged to enhance the robustness of the compensator and facilitate the compensation scheme with adaptivity to system impedance variation. Analytical assessment, simulation results, and PHIL experimental results are presented to verify the proposed compensation scheme. This scheme enables robust and stable testing of novel power technologies under varying impedance ratios representative of the complex scenarios emerging within the power sector

Comparison of phase-leg circuits for cryogenic operation in the all-electric aircraft

Commercial all-electric aircraft are projected to be flying as early as 2035, where hydrogen is selected to supply fuel and coolant. The cryogenic aircraft's powertrain includes the turbines, generators, power electronics and fan motors. As most of the powertrain is located at cryogenic temperature, it is preferable to co-locate the power electronics in the same region to reduce the engineering system's complexity. Silicon super-junction MOSFETs are known for their high efficiency, thus lower cooling requirements at cryogenic temperature. However, in phase-leg circuits, the behaviour of the MOSFET's intrinsic diode, and its output capacitance are challenging. These issues can be addressed by using the MOSFET with ancillary power devices to realise diode deactivation. This paper compares different permutations of intrinsic diode deactivation devices at room temperature and cryogenic temperature. The paper presents a demonstrator phase-leg built with different ancillary power devices. It is operated from a DC voltage of 270 V, and supplies a phase current of up to 10 A