Article Per Year (5 Year)
p-Index From 2021 - 2026
0
P-Index
This Author published in this journals
All Journal TELKOMNIKA (Telecommunication Computing Electronics and Control) Bulletin of Electrical Engineering and Informatics
Fredy H. Martínez S.
Universidad Distrital Francisco José de Caldas
Computer Science & IT Electrical & Electronics Engineering

Published : 5 Documents Claim Missing Document
Claim Missing Document
Check
Articles

Found 5 Documents
Search

 1 
Prototype of multifunctional transmitter with Rejection of disturbances Holman Montiel Ariza; Fernando Martínez Santa; Fredy H. Martínez S.
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 17, No 3: June 2019
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v17i3.12204

Abstract

The industrial instruments found in the different industrial processes allow supervisory and control actions to be carried out. These elements are usually composed of an electronic circuit, which varies according to the specifications given by the manufacturer. Another factor that influences the design of a circuit for elements of this type is cost, since, at a lower cost, electronic elements are susceptible to fail for reasons such as electric fields, motor interference or environmental conditions. This problem limits the operation of the instrument and reduces its useful life, which causes unnecessary stops of the automated processes increasing the cost of producing a product. Some partial solutions to this problem have been obtained by means of the implementation of additional circuits such as protections or filters, although the number of unexpected stops of the process is reduced, even this type of failures occur. This paper proposes an alternative solution to the problem through a low cost prototype, which has a mechanism for rejection of disturbances that increases the accuracy and precision of an instrument compared to the low-cost instrument technology developed so far.
Low cost, high performance fuel cell energy conditioning system controlled by neural network Fredy H. Martínez S.; Fernando Martínez S.; Holman Montiel Ariza
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 18, No 6: December 2020
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v18i6.16426

Abstract

Fuel cells are an important option for the generation of renewable, efficient and environmentally friendly electricity. Although there are commercial applications in the industrial, residential and automotive sectors, it is not yet a mature technology and requires much research, particularly to reduce its costs to a level competitive with other technologies. This research is currently focused not only on the structure of the cell but also on the additional elements and sub systems required for its implementation as an energy solution. In this article, we propose an electrical energy conditioning scheme for the Formic acid fuel cell (direct formic acid fuel cellor DFAFC). This fuel cell was selected for its high performance, and low cost in low and medium power applications. The proposed system consists of a direct current-direct current (DC-DC) regulator supported by a power converter controlled by a Cortex-M3 ARM processor. This CPU is used to propagate a static neural network trained with the non-linear dynamics of the power converter. The power circuit is modeled and simulated to produce  the training parameters. The neural network is trained externally and runs off-line on the processor. The results show not only the regulation capacity of the control scheme but also its response speed to sudden changes in the load.
Design of a controller for wheeled mobile robots based on automatic movement sequencing Holman Montiel Ariza; Fredy H. Martínez S.; Fernando Martínez S.
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 18, No 6: December 2020
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v18i6.16431

Abstract

There are many kinds of robots and among them the wheeled mobile robots (WMR) stand out, because they are relatively cheap and easy to build. These features make WMRs the test prototypes for control strategies or motion generation. In general, the controllers developed are based on sensory schemes that give an WMR the ability to travel through flat or obstructed environments. However, these strategies are highly reactive, i.e. they are based on the control-action scheme and are not adaptive; or, they are motion schemes built from simulations that assume the environmental conditions to determine the robot's path. In both cases, WMRs do not adapt perfectly to the change of environment, since the controller does not find appropriate movements for the  robot to move from one point to another. Therefore, this article proposesapartial solution to this problem, with a controller that generates sets of adaptive movements for an WMR to travel around its environment from the sensory perception information.
Bacterial quorum sensing applied to the coordination of autonomous robot swarms Fredy H. Martinez S.; Fernando Martinez S.; Holman Montiel A.
Bulletin of Electrical Engineering and Informatics Vol 9, No 1: February 2020
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (581.546 KB) | DOI: 10.11591/eei.v9i1.1538

Abstract

This paper proposes a strategy for the coordination of a swarm of robots in an unknown environment. The basic idea is to achieve the autonomous movement of the group from an initial region to a target region avoiding obstacles. We use a behavior model similar to bacterial Quorum Sensing (QS) as a technique for the coordination of robots. This behavior has been described as a key element in the interaction between bacteria, and we use it as a basic tool for local interaction, both between the robot and between the robot and the environment. The movement of the swarm of robots, or multi-agent robotic system, is shown as an emerging behavior resulting from the interaction of agents (in the context of artificial intelligence) from basic rules of behavior. The proposed strategy was successfully evaluated by simulation on a set of robots.
A gesture recognition system for the Colombian sign language based on convolutional neural networks Fredy H. Martínez S.; Faiber Robayo Betancourt; Mario Arbulú
Bulletin of Electrical Engineering and Informatics Vol 9, No 5: October 2020
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (617.621 KB) | DOI: 10.11591/eei.v9i5.2440

Abstract

Sign languages (or signed languages) are languages that use visual techniques, primarily with the hands, to transmit information and enable communication with deaf-mutes people. This language is traditionally only learned by people with this limitation, which is why communication between deaf and non-deaf people is difficult. To solve this problem we propose an autonomous model based on convolutional networks to translate the Colombian Sign Language (CSL) into normal Spanish text. The scheme uses characteristic images of each static sign of the language within a base of 24000 images (1000 images per category, with 24 categories) to train a deep convolutional network of the NASNet type (Neural Architecture Search Network). The images in each category were taken from different people with positional variations to cover any angle of view. The performance evaluation showed that the system is capable of recognizing all 24 signs used with an 88% recognition rate.
Co-Authors Faiber Robayo Betancourt Fernando Martínez S. Fernando Martínez Santa Holman Montiel A. Holman Montiel Ariza Mario Arbulú