Velázquez, Ramiro
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Preferred name
Velázquez, Ramiro
Official Name
Velázquez Guerrero, Ramiro
Alternative Name
rvelazquez
Main Affiliation
ORCID
Scopus Author ID
7003505296
Researcher ID
GQW-6348-2022

Research Output
Now showing 1 - 10 of 159
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Publication

Image-Based Automated Width Measurement of Surface Cracking

2021 , Miguel Carrasco , Gerardo Araya-Letelier , Velázquez, Ramiro , Paolo Visconti

The detection of cracks is an important monitoring task in civil engineering infrastructure devoted to ensuring durability, structural safety, and integrity. It has been traditionally performed by visual inspection, and the measurement of crack width has been manually obtained with a crack-width comparator gauge (CWCG). Unfortunately, this technique is time-consuming, suffers from subjective judgement, and is error-prone due to the difficulty of ensuring a correct spatial measurement as the CWCG may not be correctly positioned in accordance with the crack orientation. Although algorithms for automatic crack detection have been developed, most of them have specifically focused on solving the segmentation problem through Deep Learning techniques failing to address the underlying problem: crack width evaluation, which is critical for the assessment of civil structures. This paper proposes a novel automated method for surface cracking width measurement based on digital image processing techniques. Our proposal consists of three stages: anisotropic smoothing, segmentation, and stabilized central points by k-means adjustment and allows the characterization of both crack width and curvature-related orientation. The method is validated by assessing the surface cracking of fiber-reinforced earthen construction materials. The preliminary results show that the proposal is robust, efficient, and highly accurate at estimating crack width in digital images. The method effectively discards false cracks and detects real ones as small as 0.15 mm width regardless of the lighting conditions.

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Modelling and temperature control of shape memory alloys with fast electrical heating

2012 , Velázquez, Ramiro , Pissaloux, E.E.

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Active and Passive Haptic Perception of Shape: Passive Haptics Can Support Navigation

2019 , José Luis Rodríguez , Velázquez, Ramiro , Del-Valle-Soto, Carolina , Josué Enríquez-Zarate , Gutiérrez, Sebastián , Varona, Jorge

Real-time haptic interactions occur under two exploration modes: active and passive. In this paper, we present a series of experiments that evaluate the main perceptual characteristics of both exploration modes. In particular, we focus on haptic shape recognition as it represents a fundamental task in many applications using haptic environments. The results of four experiments conducted with a group of 10 voluntary subjects show that the differences in motor activity between active and passive haptics ease the perception of surfaces for the first case and the perception of pathways for the latter. In addition, the guidance nature of passive haptics makes the pathway direction easy to recognize. This work shows that this last observation could find application in more challenging tasks such as navigation in space.

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Modeling review of structures and locomotion systems for mobile robots: Four case studies

2011 , Velázquez, Ramiro , Aime Lay-Ekuakille

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A Novel Electronic Nose Instrument for the Detection of Volatile Hazardous Compounds: Preliminary Results

2021 , Macías-Quijas, Ricardo , Velázquez, Ramiro , Nicola, Ivan Giannoccaro , Aime Lay-Ekuakille

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An Overview of Wearable Piezoresistive and Inertial Sensors for Respiration Rate Monitoring

2021 , Roberto De Fazio , Marco Stabile , Massimo De Vittorio , Velázquez, Ramiro , Paolo Visconti

The demand for wearable devices to measure respiratory activity is constantly growing, finding applications in a wide range of scenarios (e.g., clinical environments and workplaces, outdoors for monitoring sports activities, etc.). Particularly, the respiration rate (RR) is a vital parameter since it indicates serious illness (e.g., pneumonia, emphysema, pulmonary embolism, etc.). Therefore, several solutions have been presented in the scientific literature and on the market to make RR monitoring simple, accurate, reliable and noninvasive. Among the different transduction methods, the piezoresistive and inertial ones satisfactorily meet the requirements for smart wearable devices since unobtrusive, lightweight and easy to integrate. Hence, this review paper focuses on innovative wearable devices, detection strategies and algorithms that exploit piezoresistive or inertial sensors to monitor the breathing parameters. At first, this paper presents a comprehensive overview of innovative piezoresistive wearable devices for measuring user’s respiratory variables. Later, a survey of novel piezoresistive textiles to develop wearable devices for detecting breathing movements is reported. Afterwards, the state-of-art about wearable devices to monitor the respiratory parameters, based on inertial sensors (i.e., accelerometers and gyroscopes), is presented for detecting dysfunctions or pathologies in a non-invasive and accurate way. In this field, several processing tools are employed to extract the respiratory parameters from inertial data; therefore, an overview of algorithms and methods to determine the respiratory rate from acceleration data is provided. Finally, comparative analysis for all the covered topics are reported, providing useful insights to develop the next generation of wearable sensors for monitoring respiratory parameters.

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Energy-Efficient Clustering Routing Protocol for Wireless Sensor Networks Based on Yellow Saddle Goatfish Algorithm

2020 , Rodríguez Vázquez, Alma Nayeli , Del-Valle-Soto, Carolina , Velázquez, Ramiro

The usage of wireless sensor devices in many applications, such as in the Internet of Things and monitoring in dangerous geographical spaces, has increased in recent years. However, sensor nodes have limited power, and battery replacement is not viable in most cases. Thus, energy savings in Wireless Sensor Networks (WSNs) is the primary concern in the design of efficient communication protocols. Therefore, a novel energy-efficient clustering routing protocol for WSNs based on Yellow Saddle Goatfish Algorithm (YSGA) is proposed. The protocol is intended to intensify the network lifetime by reducing energy consumption. The network considers a base station and a set of cluster heads in its cluster structure. The number of cluster heads and the selection of optimal cluster heads is determined by the YSGA algorithm, while sensor nodes are assigned to its nearest cluster head. The cluster structure of the network is reconfigured by YSGA to ensure an optimal distribution of cluster heads and reduce the transmission distance. Experiments show competitive results and demonstrate that the proposed routing protocol minimizes the energy consumption, improves the lifetime, and prolongs the stability period of the network in comparison with the stated of the art clustering routing protocols.

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A Wearable Dichoptic Display System

2011 , Velázquez, Ramiro , Carlos Delgado

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Design of Baseband Digital Delta-Sigma Modulators in 180nm CMOS

2015 , Varona, Jorge , Velázquez, Ramiro , Margarita Tecpoyotl Torres

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Performance Evaluation of Active and Passive Haptic Feedback in Shape Perception

2019 , Velázquez, Ramiro , Edwige Pissaloux , Del-Valle-Soto, Carolina , Masayuki Arai , Valdivia, Leonardo , Del-Puerto-Flores, J. Alberto , Gutierrez, Carlos A.

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