Rafael Caldas

Mr. Rafael Caldas


Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

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

Representative Publications

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1 September 2017 in Gait & Posture
Verified
Journal Article
Closed access
RCRafael Caldas
Rafael Caldas
MMMarion Mundt
Marion Mundt
WPWolfgang Potthast
Wolfgang Potthast
Fernando BuarqueFernando Buarque
Fernando Buarque
Bernd MarkertBernd Markert
Bernd Markert

1 March 2020 in Gait & Posture
Verified
Journal Article
Closed access
RCRafael Caldas
Rafael Caldas
TFTariq Fadel
Tariq Fadel
FBFernando Buarque
Fernando Buarque
Bernd MarkertBernd Markert
Bernd Markert

17 October 2018 in Medical Engineering & Physics
Verified
Journal Article
Closed access
RCRafael Caldas
Rafael Caldas
DMDIEGO J RATIVA MILLAN
DIEGO J RATIVA MILLAN
FNFernando Buarque de Lima Neto
Fernando Buarque de Lima Neto
Gait analysis is relevant for the functional diagnostic of several musculoskeletal disorders. Walking patterns can be analyzed using techniques such as video processing and inertial measurement units (IMU). In this work, a Self-Organizing Maps (SOM) algorithm is applied to reduce the complexity of kinematic features obtained by IMU sensors of a sample of 40 individuals. Our system provides a simpler data representation (2-D graphic) than conventional methods, which often applies statistical analysis. We have tested the proposed method to analyze typical and simulated limping gait pattern under well-controlled conditions. Based on kinematic parameters and symmetry-related features, SOM algorithm was able to organize the sample in groups of subjects with three different gait patterns, normal and limping with each lower limb. Moreover, our system may be used to evaluate the recovery of a patient, offering intuitive information of his walking pattern in an assessment report. However, further research with atypical-gait subjects is necessary before applying such method as a clinical tool.


19 February 2020 in Medical Engineering & Physics
Verified
Journal Article
Closed access
RCRafael Caldas
Rafael Caldas
RSRebeca Sarai
Rebeca Sarai
FNFernando Buarque de Lima Neto
Fernando Buarque de Lima Neto
Bernd MarkertBernd Markert
Bernd Markert
Age-associated changes in walking parameters are relevant to recognize functional capacity and physical performance. However, the sensible nuances of slightly different gait patterns are hardly noticeable by inexperienced observers. Due to the complexity of this evaluation, we aimed at verifying the efficiency of applied hybrid-adaptive algorithms to cluster groups with similar gait patterns. Based on self-organizing maps (SOM), k-means clustering (KM), and fuzzy c-means (FCM), we compared the hybrid algorithms to a conventional FCM approach to cluster accordingly age-related groups. Additionally, we performed a relevance analysis to identify the principal gait characteristics. Our experiments, based on inertial-sensors data, comprised a sample of 180 healthy subjects, divided into age-related groups. The outcomes suggest that our methods outperformed the FCM algorithm, demonstrating a high accuracy (88%) and consistent sensitivity also to distinguish groups that presented a significant difference (p < .05) only in one of the six observed gait features. The applied algorithms showed a compatible performance, but the SOM + KM required less computation cost and, therefore, was more efficient. Furthermore, the results indicate the overall importance of cadence, as a measurement of physical performance, especially when clustering subjects by their age. Such output provides valuable information to healthcare professionals, concerning the subject's physical performance related to his age, supporting and guiding the physical evaluation.

30 December 2021 in IEEE Access
Verified
Journal Article
Open access
RSRebeca Sarai
Rebeca Sarai
FTFrancis Trombini-Souza
Francis Trombini-Souza
VMVitoria Thaysa Gomes de Moura
Vitoria Thaysa Gomes de Moura
RCRafael Caldas
Rafael Caldas
Fernando BuarqueFernando Buarque
Fernando Buarque
Activities of daily living require efficient management between motor and cognitive tasks, known as dual tasks. The ability to properly perform such activities progressively decreases with aging. Hence, there is much effort in developing methods to identify relevant features and attenuate this functional loss. This study aimed at testing the ability of some intelligent algorithms to identify and differentiate functional features in community-dwelling older adults undergoing two 24-weeks dual-task training protocols. Additionally, we intended to provide a clear breakdown of the functional performance of the participants after undergoing two types of dual-task training protocols. We utilized the database from the EQUIDOSO-I clinical trial as input to four different types of intelligent classifiers. The algorithm’s performances were analysed considering accuracy, precision, sensitivity, and specificity. Individually, SVM achieved a higher value for sensitivity for one population group, but the remaining metrics continued to report low metrics indicating poor generalization ability of the model. Nonetheless, AdaBoost presented the most consistent results at the end of the intervention period (T2). No between-group difference affected the models’ accomplishments, corroborated by the similar performances at the baseline (T1) and the 6-month follow-up (T3). Therefore, future works should focus on establishing distinct protocols to enhance functional aspects of older adults.