Carlos Hernández-Mejía

Dr. Carlos Hernández-Mejía

Instituto Tecnológico Superior de Misantla, Misantla, Veracruz, Mexico
orcid
Profesor-Investigador en matemáticas aplicadas y sistemas in...

Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
10 January 2022 in Technologies
Verified
Journal Article
Open access
PDF file
AEAlfonso Navarro Espinoza
Alfonso Navarro Espinoza
OBOscar Lopez Bonilla
Oscar Lopez Bonilla
EGEnrique García Guerrero
Enrique García Guerrero
Esteban Tlelo-CuautleEsteban Tlelo-Cuautle
Esteban Tlelo-Cuautle
DLDidier López-Mancilla
Didier López-Mancilla
Everardo Inzunza-GonzalezEverardo Inzunza-Gonzalez
Everardo Inzunza-Gonzalez
Nowadays, many cities have problems with traffic congestion at certain peak hours, which produces more pollution, noise and stress for citizens. Neural networks (NN) and machine-learning (ML) approaches are increasingly used to solve real-world problems, overcoming analytical and statistical methods, due to their ability to deal with dynamic behavior over time and with a large number of parameters in massive data. In this paper, machine-learning (ML) and deep-learning (DL) algorithms are proposed for predicting traffic flow at an intersection, thus laying the groundwork for adaptive traffic control, either by remote control of traffic lights or by applying an algorithm that adjusts the timing according to the predicted flow. Therefore, this work only focuses on traffic flow prediction. Two public datasets are used to train, validate and test the proposed ML and DL models. The first one contains the number of vehicles sampled every five minutes at six intersections for 56 days using different sensors. For this research, four of the six intersections are used to train the ML and DL models. The Multilayer Perceptron Neural Network (MLP-NN) obtained better results (R-Squared and EV score of 0.93) and took less training time, followed closely by Gradient Boosting then Recurrent Neural Networks (RNNs), with good metrics results but the longer training time, and finally Random Forest, Linear Regression and Stochastic Gradient. All ML and DL algorithms scored good performance metrics, indicating that they are feasible for implementation on smart traffic light controllers.

8 December 2021 in Fractal and Fractional
Verified
Journal Article
Open access
PDF file
JCJosé Daniel Colín Cervantes
José Daniel Colín Cervantes
CSCarlos Sánchez-López
Carlos Sánchez-López
RORocío Ochoa-Montiel
Rocío Ochoa-Montiel
DTDelia Torres-Muñoz
Delia Torres-Muñoz
Carlos Hernández-MejíaCarlos Hernández-Mejía
Carlos Hernández-Mejía
HGHugo G. Gonzalez-Hernandez
Hugo G. Gonzalez-Hernandez
This paper deals with the study and analysis of several rational approximations to approach the behavior of arbitrary-order differentiators and integrators in the frequency domain. From the Riemann–Liouville, Grünwald–Letnikov and Caputo basic definitions of arbitrary-order calculus until the reviewed approximation methods, each of them is coded in a Maple 18 environment and their behaviors are compared. For each approximation method, an application example is explained in detail. The advantages and disadvantages of each approximation method are discussed. Afterwards, two model order reduction methods are applied to each rational approximation and assist a posteriori during the synthesis process using analog electronic design or reconfigurable hardware. Examples for each reduction method are discussed, showing the drawbacks and benefits. To wrap up, this survey is very useful for beginners to get started quickly and learn arbitrary-order calculus and then to select and tune the best approximation method for a specific application in the frequency domain. Once the approximation method is selected and the rational transfer function is generated, the order can be reduced by applying a model order reduction method, with the target of facilitating the electronic synthesis.

3 June 2024 in Technologies
Verified
Journal Article
Open access
PDF file
Jorge Galarza-FalfanJorge Galarza-Falfan
Jorge Galarza-Falfan
EGEnrique García Guerrero
Enrique García Guerrero
OCOscar Adrian Aguirre Castro
Oscar Adrian Aguirre Castro
OBOscar Lopez Bonilla
Oscar Lopez Bonilla
UTUlises-Jesus Tamayo-Perez
Ulises-Jesus Tamayo-Perez
Everardo Inzunza-GonzalezEverardo Inzunza-Gonzalez
Everardo Inzunza-Gonzalez
Machine learning technologies are being integrated into robotic systems faster to enhance their efficacy and adaptability in dynamic environments. The primary goal of this research was to propose a method to develop an Autonomous Mobile Robot (AMR) that integrates Simultaneous Localization and Mapping (SLAM), odometry, and artificial vision based on deep learning (DL). All are executed on a high-performance Jetson Nano embedded system, specifically emphasizing SLAM-based obstacle avoidance and path planning using the Adaptive Monte Carlo Localization (AMCL) algorithm. Two Convolutional Neural Networks (CNNs) were selected due to their proven effectiveness in image and pattern recognition tasks. The ResNet18 and YOLOv3 algorithms facilitate scene perception, enabling the robot to interpret its environment effectively. Both algorithms were implemented for real-time object detection, identifying and classifying objects within the robot’s environment. These algorithms were selected to evaluate their performance metrics, which are critical for real-time applications. A comparative analysis of the proposed DL models focused on enhancing vision systems for autonomous mobile robots. Several simulations and real-world trials were conducted to evaluate the performance and adaptability of these models in navigating complex environments. The proposed vision system with CNN ResNet18 achieved an average accuracy of 98.5%, a precision of 96.91%, a recall of 97%, and an F1-score of 98.5%. However, the YOLOv3 model achieved an average accuracy of 96%, a precision of 96.2%, a recall of 96%, and an F1-score of 95.99%. These results underscore the effectiveness of the proposed intelligent algorithms, robust embedded hardware, and sensors in robotic applications. This study proves that advanced DL algorithms work well in robots and could be used in many fields, such as transportation and assembly. As a consequence of the findings, intelligent systems could be implemented more widely in the operation and development of AMRs.

Verified
Journal Article
Open access
PDF file
VMVíctor Martínez-Sánchez
Víctor Martínez-Sánchez
Iván Esteban Villalón TurrubiatesIván Esteban Villalón Turrubiates
Iván Esteban Villalón Turrubiates
FCFrancisco Cervantes
Francisco Cervantes
Carlos Hernández-MejíaCarlos Hernández-Mejía
Carlos Hernández-Mejía
This research explores a novel Mexican Sign Language (MSL) lexicon video dataset containing the dynamic gestures most frequently used in MSL. Each gesture consists of a set of different versions of videos under uncontrolled conditions. The MX-ITESO-100 dataset is composed of a lexicon of 100 gestures and 5000 videos from three participants with different grammatical elements. Additionally, the dataset is evaluated in a two-step neural network model as having an accuracy greater than 99% and thus serves as a benchmark for future training of machine learning models in computer vision systems. Finally, this research provides an inclusive environment within society and organizations, in particular for people with hearing impairments.

9 August 2018 in Arabian Journal for Science and Engineering
Verified
Journal Article
Closed access
PDF file
Carlos Hernández-MejíaCarlos Hernández-Mejía
Carlos Hernández-Mejía
HVHéctor Vázquez-Leal
Héctor Vázquez-Leal
ASAlfonso Sánchez-González
Alfonso Sánchez-González
ÁCÁngel Corona-Avelizapa
Ángel Corona-Avelizapa

15 August 2022 in Logistics
Verified
Journal Article
Open access
PDF file
Carlos Hernández-MejíaCarlos Hernández-Mejía
Carlos Hernández-Mejía
DTDelia Torres-Muñoz
Delia Torres-Muñoz
Everardo Inzunza-GonzalezEverardo Inzunza-Gonzalez
Everardo Inzunza-Gonzalez
CSCarlos Sánchez-López
Carlos Sánchez-López
EGEnrique García Guerrero
Enrique García Guerrero
Background: The health crisis due to COVID-19 has changed the habits of social coexistence and therefore has had a significant impact on several economic sectors, including logistics. Nowadays, this sector faces one of the most difficult challenges in history and hence has carried out innovative strategies to adjust to the new normal and guarantee the permanence of the supply chain. In this paper, a novel green logistics technique for planning merchandise deliveries is introduced herein. Methods: This technique is based on a modified version of the Resistive Grid Path Planning Methodology (RGPPM) to establish a path through georeferential locations for delivering merchandise to customers. To do this, multi-connected resistive grids are based at customer locations for searching the path connecting the positions through electronic circuit analysis techniques. Results: Experimental results reveal that the proposed method can find a minimum spanning tree that connects all hand-over points by a continuous path. This finding has represented a reduction of around 45% in the length of the path with respect to the longest path. Conclusions: Finally, this technique is capable of addressing different optimization strategies, locating a merchandise distribution center and exploring environmental standards to reduce fuel consumption.