IEEE Latin America Transactions

This work analyzes the waves of currents in residential loads, evaluating the effects of attenuation and diversity in the cancellation of harmonics, pondering their influence in the prediction of distortion indexes in a distribution system. Starting from signals of currents registered in laboratory and subsequently treated with Fast Fourier's Transformation, the loads were modeled like sources of ... View full abstract»

Software product quality is an important concern in the computer environment and whose immediate results are appreciated in all the activities where computers are used. The ISO/IEC 9126 standard series settle a software product quality model, for example, in the annex, shows the identification of the quality requirements like a necessary step for product quality. However, the standard does not inc... View full abstract»

The present document is a revision of the state-of-the-art of the problem of the life of the power transformer immersed in oil. The problem of the difference between life of the isolation and life of the power transformer is reviewed, the loading guides of IEEE and IEC are analyzed and, the difference that exists between both loading guides to different values of temperature is shown. View full abstract»

This paper describe the modeling and simulation of current transformers (TC's), used with protective relays, with data of tests of laboratory, of saturation and relation, determining its answer, regarding different conditions gives the electric system. The analysis of model it is based on the simulation of the TC's, using the saturable transformer model from the ElectroMagnetic Transient Program (... View full abstract»

In this paper, a methodology for calculating the setting impedance of zones 2 and 3 of distance relays is presented, The aim is to reduce protection coordination problems during fault occurrence and changes in the network configuration. The proposed method is based on the impedance seen by the distance relay when faults are simulated on adjacent nodes. The coordination and relay setting is obtaine... View full abstract»

The IEC61131-3 standardized five PLC programming languages and presents a software model that stimulates practices such as code reuse. The adoption of this standard in the modernization of the Brazilian Navy mine-sweepers allowed the development of a reliable software, easy to test and maintain, with high productivity. Although the PLC used in this project did not provide natively all the language... View full abstract»

This paper studies the consequences of having solid state starters with long term ramps in a real pumping case. The harmonic resonances due to the necessary reactive power compensation capacitors and the short circuit impedance is analyzed. Electromagnetic Compatibility standards are checked in order to explain the frequent failure of the starters. One time proposed the disconnection of the capaci... View full abstract»

A grounding grid is designed with the capacity to minimize the very fast transient overvoltage generated during switching operations in a Gas Insulated Substation (GIS). The methodology takes the reference from the IEEE Std. 80-2000 and contains detailed models of GIS and grounding grid. By means an iterative process, new elements are added to the grounding grid for reducing magnitude of a very fa... View full abstract»

Although risk management approaches appeared more than one decade ago, there is the evidence of low penetration rate of their techniques in current software projects. One of the most widely known methods is the SEI Software Continuous Risk Management (SEI-CRM) method. This paper addresses the usage of the SEI-CRM method in a big university software development project. Moreover, the study we carri... View full abstract»

This paper presents a study of encrypted multimedia files in order to identify the encryption algorithm. Audio and video files were encoded with distinct cryptographic algorithms and then metadata were extracted from these cryptograms. The algorithm identification is obtained by using data mining techniques. Therefore, the procedure first stage performs the encryption of audio and video files usin... View full abstract»

Fourth generation (4G) cellular systems have been optimized to provide high data rates and reliable coverage to mobile users. New waveforms at the physical layer are needed. Generalized frequency division multiplexing (GFDM) is a candidate modulation for the fifth generation (5G) standard based on multi-branch multicarrier filter bank approach. A main characteristic of GFDM is its low out of band ... View full abstract»

The present document is the continuation of part I of the state-of-the-art of the life of power transformers immersed in oil. A revision, of the correlation that exits between the degree of polymerization and the content of furans, is done. The advantages and disadvantages of the methods used to know the life of insulation from power transformer are shown and a classification of the tools used in ... View full abstract»

The Internet of things (IoT) will interconnect a huge amount of devices, leading to a new way of interaction in the physical and virtual world, inspired by the idea of ubiquity, where all the objects around us, such as: sensors, automobiles, refrigerators, thermostats, industrial robots, tablets, smartphones, etc. could be connected anytime and anywhere. However, one of the main challenges that fa... View full abstract»

This paper involves an application of PID controllers topologies, deployed in an Arduino platform, applied to a didactic thermal plant. The tuning parameters of the controller are performed by experimental methods, in which have been chosen from the Ziegler-Nichols method (step response) and the CHR (Chien, Hrones and Reswick) method of tuning. Routines were created in Matlab and Arduino to provid... View full abstract»

Benchmarking, mission declaration, revision of maintenance strategies and reengineering were popular activities in the ninety. Big amounts of money were invested and the results many times were not good enough, or nonexistent. Then, what should improve the maintenance/performance of our assets? In this paper we discuss about available tools, their potential benefits, weaknesses and their strengths... View full abstract»

A multi-objective methodology for locating, sizing and operation of energy storage devices in distribution systems considering a typical load curve on a horizon of 24 hours is presented. The objective functions of the problem are minimization of power losses and the installation cost of the energy storage devices. The proposed methodology considers two optimization stages through a master-slave op... View full abstract»

New and different trends in networks have been promoted in recent years, among these, Network Functions Virtualization (NFV) has emerged as an initiative from the industry (manufacturers and network operators) in order to increase the flexibility of deployment and integration of new network services within operator's networks. This is achieved through the implementation of network functions such a... View full abstract»

This paper presents an analytical and numerical evaluation of a single-stator, single rotor axial-flux induction prototype, with squirrel cage made of copper. Additionally a set of experimental test are carried out to validate those models. In order to estimate the magnetizing current required for the motor the Carter factor is calculated for different airgap lengths. Traditional equivalent circui... View full abstract»

Data generation and publication on the Web has increased over the last years. This phenomenon, usually known as “Big Data”, poses new challenges related with Volume, Velocity, and Variety (“The three V's”) of data. The Semantic Web offers the means to deal with variety, where RDF (Resource Description Framework) is used to model data in the form of triples subject-predi... View full abstract»

Precision agriculture requires the use of automation techniques to improve the productivity through optimization of natural resources. Therefore, continuous data acquisition of environmental, soil and crop variables must be conducted real-time. Data-loggers are typically used with sensors and actuators to implement automated actions within precision agriculture. However commercially available data... View full abstract»

Improvement in software development processes gives companies guaranteed high levels of maturity in their processes and increases their competitiveness in international terms. There are improvement, assessment and quality models which enjoy world-wide recognition but which must be adapted to the particular characteristics of the specific countries where those models are applied. These models can n... View full abstract»

The migration of legacy web applications (LWA) to Service Oriented Architectures (SOA) has become mainstream in the last years due to the architectural flexibility that SOA provides, which allows to easily adapt the existing applications to new requirements. However, these migrations are usually ad-hoc and manually performed leading to tedious and error-prone processes. MigraSOA is an approach to ... View full abstract»

Current energy policies are encouraging the connection of power generation based on low-polluting technologies, mainly those using renewable sources to distribution networks. The photovoltaic (PV) systems have experienced a great growth around the word in last years. Hence, it becomes increasingly important to understand technical challenges, facing high penetration of PV systems at the grid, espe... View full abstract»

In optical networks, failures can imply in great loss of data due to high transmission rates, leading to the need of employment of protection mechanisms. This paper introduces a novel algorithm to provide Failure-independent path protecting p-cycle with minimum interference for path protection in elastic optical networks using space division multiplexing. The proposed protection algorithm reduces ... View full abstract»

The emergence of Wireless Sensor Network enabled the pervasive monitoring of local environments, however, to better suit the large scale requirements for Information Technology industry applications, the devices must be able to operate within the internet infrastructure. The IoT (Internet of Things) has emerged to fill this gap and deliver sensed data widely, therefore increasing the connectivity ... View full abstract»

Technological advances allowed in recent years the development of numerous applications and systems that improve people's lives in various sectors, especially the home automation. Already the wireless communication has become dominant in the data transmission segment to allow greater adaptability and flexibility in access to multiple devices among users, and networks based on wireless protocols (I... View full abstract»

At present, electric vehicles are charged at home at night when lower off-peak rates could apply. The purpose of this pilot project is to demonstrate the viability of providing renewable power charging services for electric vehicles at railway station parking lots for commuters during the day. The power needed to feed the charging station comes from a photovoltaic system as well as from the regene... View full abstract»

This article proposes that the combination of smoothing approach considering the entropic information provided by Renyi's method, has an acceptable performance in term of forecasting errors. The methodology of the proposed scheme is examined through benchmark chaotic time series, such as Mackey Glass, Lorenz, Henon maps, the Lynx and rainfall from Santa Francisca - Cordoba, with addition of white ... View full abstract»

Many environments for electrical and electronic circuits simulation available on the market offer packages dedicated to electrical machines and renewable energy elements. Although very useful for simulating wind energy conversion systems (WECS), for example, these blocks are typically locked, preventing changes being made in them. Thus, this article aims to build blocks for dynamic simulation of h... View full abstract»

In this work, the Power Summation Method is adapted to be applied in distribution systems that include distributed generation. The voltage control at the generation buses is treated as an optimization problem, which uses the Newton-Raphson method as the minimization technique. The algorithm is iterative and includes the reactive and voltage limits constraints for each generator. The accuracy and c... View full abstract»

In this paper, a non-linear programming model to operate distribution systems considering energy storage devices and distributed generation is presented. Mathematical formulation is made taking in to account four terms for minimization: The cost operation of the electrical grid, reducing greenhouse emissions, reduction of electrical losses in conductors and voltage profile improve. As model constr... View full abstract»

This paper presents a wind power generation system (WPGS) with battery energy storage system (BESS) based on the Z-source inverter (ZSI) with simple boost control. Wind turbines using the squirrel cage induction generator (SCIG) are widely accepted due to their robustness, simplicity, light weight and low cost. The SCIG is connected to the power grid through voltage source converters VSC, and the ... View full abstract»

In order to use Wireless Sensor Networks (WSN) in the Internet of Things (IoT) a series of convergence challenges must be identified and addressed. In this work current ZigBee and 6LoWPAN network architectures are reviewed and compared to IoT requirements. As a result it is concluded that power constraints, security and quality of service parameters will be key to design heterogenuos wireless sens... View full abstract»

This article presents a novel model of mixed integer linear programming (MILP) to conduct network planning (Fiber-Wireless-FiWi) that along a timeline space facilitates growth, expansion and scalability of resources involved in communications network, traditionally used in cellular telephony, and is possible that extends as a multiservice network to provide smart metering, as is the case in Advanc... View full abstract»

Falls can result in physical and psychological trauma, especially for the elderly. In order to improve the quality of life of these patients this work presents the development of a fall detection and body positioning with a heart rate monitoring system. This system consists of the sensing equipment, gateway and a real-time patient monitoring structure. The sensing device obtains information from a... View full abstract»

In this paper, we present the design, construction and implementation of a solar-wind hybrid system to obtain electric energy at low cost. Wind and solar power are becoming the alternative energies sources more popular, due to their abundance, availability and ease to obtain electric power. This research covers the construction of a hybrid renewable energy system for house applications, which uses... View full abstract»

The Watershed Transform (W.T.) is a useful morphological tool that allows to distinguish complex structures that can not be processed with image processing conventional algoriths. The W.T. floods the image gradient topography from its local minima. These minima indicates the zones where the flooding starts in order to segment the image. The final result is a labeled image where each pixel belongs ... View full abstract»

This paper presents the modeling and experimental validation of a new topology for the DC/DC Buck power converter-DC motor system. The main objective of this topology is to achieve a bidirectional rotation on the DC motor shaft by using a DC/DC power converter. As a result of applying Kirchhoff's current and voltage laws the system mathematical model is obtained. Also, an analysis in steady-state ... View full abstract»

This work presents the algorithm design of classic control, fuzzy control and neural control applied to a level control prototype. Classic control systems use PI and PID control actions; in order to tune such actions, Ziegler and Nichols oscillating method was used. It was designed a proportional, derivative and incremental fuzzy control system. As well, an inverse mode neural controller and an in... View full abstract»

This paper presents a system for detecting intrusions when analyzing the network traffic payload looking for malware evidences. The system implements the detection algorithm as a Snort preprocessor component. Since they work together, a highly effective system against known attacks has been achieved (based on Snort rules) and a highly effective system against unknown threats (which was the main ai... View full abstract»

This paper presents a reliability-based method aiming to improve the availability of gas turbine installed in combined-cycle thermoelectric power plant. The importance of the gas turbine is related with the power plant operational principle. The gas turbine transforms the chemical energy generated by combustion in mechanical energy to rotate the generator's shaft. The exhaust gas is used to heat w... View full abstract»

Digital TV standards are continuously evolving in order to provide users with livelier experiences. Nowadays, the trend in digital TV is to investigate the evolution of present systems to enable the transmission of 8K video programs. In order to do so, the physical layer of the system has to be adapted to be able to transmit the required bit rate. On the other hand, the modulation technique Filter... View full abstract»

This paper describes an original method of analysis based on the classical circuit theory, traveling waves and the superposition principle, developing a solution method in time domain, which avoids working with complicated differential equations. This alternative breaks the transmission line down in a set of very short cells, obtaining a Thevenin equivalent model at each end and intermediate point... View full abstract»

The distribution system reconfiguration problem is concerned with finding the state of all switches in a set of primary distribution feeders so that a given objective function is optimised, typically the minimisation of the total electrical loss. Constraints such as Kirchhoffpsilas Current Law (KCL) and branch capacity are usually enforced. An additional and important constraint is also imposed so... View full abstract»

This work analyzes the categorical metrics usage on a very specific subset of Intelligent Systems: Fuzzy Systems. Several characteristics for such systems must be carefully evaluated when metrics and indicators are defined, in order to consider the fuzzy essence as part of the evaluation result. A set of metrics and indicators are defined and applied to the classical inverted pendulum problem. The... View full abstract»

The Future Internet is expected to support services in both existing and new scenarios, in terms of mobility, quality, scalability and security, among other. In this work we present how Reconfigurable Computing (RC) may contribute to build Future Internet (FI) flexibility and security. Therefore, we discuss some aspects of FI initiatives which can be addressed by Reconfigurable Computing. Then we ... View full abstract»

This article proposes a multivariable robust controller for the regulation of DC motor angular speed, and for the active current sharing in each parallel DC/DC buck converter. Considering that the parallel DC/DC buck converter is connected in cascade to the armature of the DC motor. Additionally, the controller rejects actively the internal and external disturbances, which is subjected the multiva... View full abstract»

Malware Analysis and Classification Systems use static and dynamic techniques, in conjunction with machine learning algorithms, to automate the task of identification and classification of malicious codes. Both techniques have weaknesses that allow the use of analysis evasion techniques, hampering the identification of malwares. In this work, we propose the unification of static and dynamic analys... View full abstract»

This paper presents and analyzes the experience of applying certain data mining methods and techniques on 932 Systems Engineering students' data, from El Bosque University in Bogotá, Colombia; effort which has been pursued in order to construct a predictive model for students' academic performance. Previous works were reviewed, related with predictive model construction within academic env... View full abstract»

The Distributed Generation (DG) has substantially increased around the world and it is expected to play an important role in the future of power systems. Most of DG systems are composed by renewable energy sources, such as Photovoltaic (PV), which has an intermittent behavior, resulting in negative impacts on the distribution network, such as voltage fluctuation. In order to mitigate the voltage r... View full abstract»