Revista EIA / English version

Editorial

Ricardo León Restrepo Arango — Thu, 26 Oct 2017 00:00:00 -0500

Silent Science

What would happen if human beings were not curious and did not seek knowledge? Can we live without science? Could we really exist as a species without science? The rest of the living beings on this planet have done it and will continue to do so, but not us.

Study of the Structural and Magnetic Properties of Gd0.257-xNdxFe0.743 as Obtained by Mechanical AlloyinG

Thu, 26 Oct 2017 00:00:00 -0500

This paper presents the study of structural and magnetic properties in the composition Gd_0.257-xNd_xFe_0.743 where x = 0, 0.1285, 0.257 prepared by mechanical alloying in an argon atmosphere and with a milling time of 72 hours using a high energy planetary mill. The magnetic and structural characterization was performed by Mössbauer Spectroscopy (MS) and X-Ray diffraction (XRD), respectively. The three patterns show an intense peak corresponding to the α-Fe phase. Its intensity decreases as Gd is replaced by Nd showing the minimum intensity for x =0.257, and at the same time it shows a progressive increase in the peak’s width. These effects are attributed to the rich presence of Gd and/or Nd atoms in the iron sites. Mössbauer spectra were adjusted with hyperfine field distributions, sextets and singlets using the Mosfit program. The spectra show that by substituting the Gd with Nd atoms, the magnetic order is affected in such a way that iron sites appear and show magnetic disorder.

Regionalization of Flow Duration Curves in the State of Antioquia, Colombia

Santiago Gallego Arias, Luis Fernando Carvajal Serna — Thu, 26 Oct 2017 00:00:00 -0500

Water resource design and projects need sufficient information and data processes to ensure proposed hydraulic structures are successful. Many hydrological studies have no observed data for discharges in the basins, and one of the most commonly used concepts for previous hydrological studies is the flow duration curve. This work shows a new approach to estimate the flow duration curve in basins for which there is no information. The proposal presents a calibrated equation for each of the six regions in the state of Antioquia, in the northwest of Colombia. Veering from the traditional approach, it includes the non-exceedance probability. The statistical analysis conducted shows a fitting error of less than 13% for all regions in Antioquia except Urabá, which has an error of 44%.

A Practical Approach to Develop Centralized Inventory Policies for 1-Warehouse/N-Retailers Systems Through Simulation/Optimization

Liliana Delgado, Héctor Hernán Toro, Juan José Bravo — Thu, 26 Oct 2017 00:00:00 -0500

Collaboration in supply chain management has become a key success factor. Operational strategies in which each node operates under optimum operating conditions have proven to be inadequate, and it has been determined that a strategy of coordination of the chain as a whole is best perceived. The One-warehouse N-retailer chain typically operates with each retailer placing orders to the warehouse according to its own inventory policies. In this article we study the case where the warehouse makes centralized decisions, defining retail inventory replenishment policies using the (R, s, S) periodic review policy. The optimal policy is determined using a heuristic that combines Monte Carlo simulation with Optimization, based on an implementation in a spreadsheet scheme. The approach is tested in one case, showing reductions in the relevant inventory costs when centralized versus decentralized approaches are compared.

Systemic Evaluation of a Policy of Volume Flexibility in a Papaya Distribution Supply Chain

Andrés Mauricio Paredes Rodríguez, Andrés Felipe Salazar Ramos — Thu, 26 Oct 2017 00:00:00 -0500

Volume flexibility is used in this article to determine responsiveness to changes in the deterioration factors of perishable stages in a supply chain. The main objective of this study is to evaluate the impact of this strategy on two key indicators for network performance, such as logistics costs and service levels. The research involves the operation of a papaya distribution network formed by a producer and a retailer, which is simulated through System Dynamics. A policy of flexibility is achieved, which dramatically improves volume indicators such as the level of service and costs considered in the study. However, using this strategy involves taking on a higher cost of inventory storage and an additional cost of capacity increase.

Heuristic Assessment of Software Usability to Facilitate Computer Use for People with Motor Disabilities

Thu, 26 Oct 2017 00:00:00 -0500

There are diseases that make it difficult to use computational tools efficiently. Of course, some entities and research centers develop software applications to facilitate the accessibility and usability of equipment for people suffering from diseases that significantly alter their motor skills. Tests are conducted to ensure the software product performs the functions for which it was designed. One of them is the usability evaluation of the software, which is often done empirically. This article proposes a method with a heuristic approach to evaluate the utility of software designed to facilitate computing access for people with motor disabilities. Often, as regards usability issues, a developer who does not know the specific needs of the people mistakenly approaches the software design guidelines. This research is particularly relevant because users with medical conditions assign weight to software features that usability experts consider important.

Comparison of Higuchi, Katz and Multiresolution Box-Counting Fractal Dimension Algorithms for EEG Waveform Signals Based on Event-Related Potentials

Santiago Fernández Fraga, Jaime Rangel Mondragón — Thu, 26 Oct 2017 00:00:00 -0500

Obtaining information through the measurement of brain signals recorded during different processes or physiological conditions is important for developing computer interfaces that translate electrical brain signals to computer control commands. Electroencephalography (EEG) records the electrical activity of the brain in response to its receipt of different external stimuli (potential events). Analysis of these signals makes it possible to identify and distinguish specific states of physiological brain function. The Fractal Dimension has been used as a tool for biomedical waveform analysis, in particular to measure the complexity of time series generated by EEG. This paper aims to analyze a database (HeadIT) of biomedical time series obtained by EEG for which the fractal dimension will be obtained by the Higuchi, Katz and multiresolution box-counting methods, showing the relationship between the method for obtaining the fractal dimension and the physiological condition of the brain event-related potentials.

Methodology proposal to determine project management maturity level in engineering companies

Thu, 26 Oct 2017 00:00:00 -0500

The purpose of this paper is to present a methodological proposal for small engineering companies to evaluate its project management maturity level. The proposal is based on a generic standard which was adjusted by consulting internal and external experts, to establish particular evaluation criteria and qualification scale to perform best practices evaluation. The proposal considers not only general maturity level qualification but also, by multivariate statistics, qualification by processes groups and experts groups. The proposal was validated through a case study, when applied in an engineering company, resulting on that external experts tend to qualify the maturity of management of projects higher than internal experts, the company´s employees.

Undesired Splash Over on Equipments Using Inductive Sensors for Monitoring Automotive Vehicles’ Controlled Speed

Silvio Monteiro, Maurício Réche, Altair S. de Assis — Thu, 26 Oct 2017 00:00:00 -0500

This article aims to evaluate instruments that oversight traffic flow electronically, using inductive surface sensors, based on the change of local magnetic field. More specifically, we study the possibility of false speed detections, due to the manifestation of the phenomenon called splash over — which means a space splash of the magnetic field lines out of the measuring zone. We show, through the literature, and practical simulations, the damage that can be caused by splash on the correct speed measurement and identification of the car under suspicions. It is also presented solutions to inhibiting unwanted velocity measurements due to this effect.

Remote Protein Homology Detection Using Physicochemical Properties

Óscar Bedoya — Thu, 26 Oct 2017 00:00:00 -0500

A new method for remote protein homology detection, called CDA (Characteristic Distribution Analysis), is presented. The CDA method uses the distributions of physicochemical properties of amino acids for each protein. Given the training sequences of a SCOP (Structural Classification Of Proteins) family, a characteristic distribution is achieved by averaging the values of the distributions of its proteins. The hypothesis in this research is that each protein family F has a characteristic distribution that separates its sequences from the rest of the proteins in a dataset. A set of 72 physicochemical properties was selected to create different characteristic distributions of the same family. Each characteristic distribution is used as a classifier. Finally, a Naive Bayes classifier is trained to combine the information of the individual classifiers and obtain a better decision. We found that each family has a set of physicochemical properties that allow the discrimination of their sequences better. CDA achieves a True Positive (TP) rate of 0,793, a False Positive (FP) rate of 0,005, and a Receiver Operating Characteristic (ROC) area of 0,918. The CDA method outperforms some of the current strategies such as SVM-PCD and SVM-RQA.