36 documents found, page 1 of 4
Confidence intervals for the reliability of dependent systems: Integrating frai...
Bru-Cordero, Osnamir E.; Castro, Cecilia; Leiva, Víctor; Jaramillo-Elorza, Mario C.Most reliability studies assume large samples or independence among components, but these assumptions often fail in practice, leading to imprecise inference. We address this issue by constructing confidence intervals (CIs) for the reliability of two-component systems with Weibull distributed failure times under a copula-frailty framework. Our construction integrates gamma-distributed frailties to capture unobse...
Multi-strain COVID-19 dynamics with vaccination strategies: mathematical modeli...
Ambalarajan, Venkatesh; Mallela, Ankamma Rao; Dhandapani, Prasantha Bharathi; Sivakumar, Vinoth; Leiva, Víctor; Castro, CeciliaThe emergence of alpha, beta, gamma, and delta COVID-19 variants has posed important challenges to global health. Understanding the transmission dynamics and evaluating the impact of vaccination strategies are critical for effective pandemic management. The present study develops a novel mathematical model that incorporates time-dependent vaccination rates to analyze the spread of these four COVID-19 variants, ...
Multi-factor optimization and failure-tolerant design of cable-driven parallel ...
Ghaffar, Asim; Zia Ur Rahman, Muhammad; Leiva, Víctor; Castro, Cecilia; Martin-Barreiro, CarlosThis article presents a framework for optimizing cable-driven parallel manipulators (CPMs) in deep-sea environments, addressing factors as failure tolerance, stiffness, and workspace within a unified framework. While previous studies have examined these factors individually, few have integrated them into a unified framework. The presented framework evaluates CPMs with six, eight, and ten cables, using inverse k...
A real-time intelligent system based on machine-learning methods for improving ...
Leiva, Víctor; Rahman, Muhammad Zia Ur; Akbar, Muhammad Azeem; Castro, Cecilia; Huerta, Mauricio; Riaz, Muhammad TanveerIn this article, we introduce a cost-effective and real-time intelligent system tailored to Pakistan sign language (PSL) recognition, aimed at facilitating communication for hearing-impaired individuals. The system utilizes a specialized glove equipped with flex sensors and an MPU-6050 device to capture finger movements and hand orientation in a three-dimensional space. A dataset comprising ten unique PSL signs...
A six-compartment model for COVID-19 with transmission dynamics and public heal...
Ambalarajan, Venkatesh; Mallela, Ankamma Rao; Sivakumar, Vinoth; Dhandapani, Prasantha Bharathi; Leiva, Víctor; Martin-Barreiro, Carlos; Castro, CeciliaThe global crisis of the COVID-19 pandemic has highlighted the need for mathematical models to inform public health strategies. The present study introduces a novel six-compartment epidemiological model that uniquely incorporates a higher isolation rate for unreported symptomatic cases of COVID-19 compared to reported cases, aiming to enhance prediction accuracy and address the challenge of initial underreporti...
A hybrid fuzzy mathematical programming approach for manufacturing inventory mo...
Dhandapani, Prasantha Bharathi; Kalaichelvan, Kalaiarasi; Leiva, Víctor; Castro, Cecilia; Ramalingam, SoundariaThis study introduces an inventory model for manufacturing that prioritizes product quality and cost efficiency. Utilizing fuzzy logic and mathematical programming, the model integrates fuzzy numbers to describe uncertainties associated with manufacturing costs and quality control parameters. The model extends beyond conventional inventory systems by incorporating a dynamic mechanism to halt production, employi...
Optimized design and analysis of cable-based parallel manipulators for enhanced...
Ghaffar, Asim; Rahman, Muhammad Zia Ur; Leiva, Víctor; Castro, CecíliaThe subsea exploration of complex and challenging areas has increased the need for advanced robotic frameworks, such as cable-based parallel manipulators (CPMs). Known for their flexibility and precision, CPMs are essential for performing detailed tasks underwater. In submarine environments, handling external underwater forces presents a significant challenge, necessitating the optimization of cable tension for...
Efficiency, optimality, and selection in a rigid actuation system with matching...
Ghaffar, Asim; Rahman, Muhammad Zia Ur; Leiva, Víctor; Martin-Barreiro, Carlos; Ali, Imran; Cabezas, Xavier; Castro, CeciliaSelecting the right actuator for a portable exoskeleton involves a comprehensive evaluation of various design characteristics. In this study, we introduce a methodology for actuator selection based on specific tasks, enhancing the practical adoption of portable exoskeletons. By examining a range of candidate actuators designed for lower limb exoskeletons, our objective is to engineer a system that is both light...
Symmetry and complexity in gene association networks using the generalized corr...
Ospina, Raydonal; Xavier, Cleber M.; Esteves, Gustavo H.; Espinheira, Patrícia L.; Castro, Cecilia; Leiva, VíctorHigh-dimensional gene expression data cause challenges for traditional statistical tools, particularly when dealing with non-linear relationships and outliers. The present study addresses these challenges by employing a generalized correlation coefficient (GCC) that incorporates a flexibility parameter, allowing it to adapt to varying levels of symmetry and asymmetry in the data distribution. This adaptability ...
Addressing a decision problem through a bipolar Pythagorean fuzzy approach: A n...
Kuppusamy, Vishalakshi; Shanmugasundaram, Maragathavalli; Dhandapani, Prasantha Bharathi; Martin-Barreiro, Carlos; Cabezas, Xavier; Leiva, VíctorDecision-making in real-world scenarios faces uncertainty. Fuzzy theory has been a means to represent such uncertainty. In this study, we propose an approach that incorporates bipolarity into multi-criteria decision-making processes applied to digital marketing. The proposal considers both the positive and negative dimensions of data, leading to better-informed decisions. Our contribution integrates bipolarity ...