Revista Internacional de Métodos Numéricos para Cálculo y Diseño en Ingeniería / International Journal of Numerical Methods for Calculation and Design in Engineering

RIMNI - An International Journal of Numerical Methods for Calculation and Design in Engineering (Revista Internacional de Métodos Numéricos para Cálculo y Diseño en Ingeniería) is a peer-reviewed Open Access journal, founded in 1985. RIMNI publishes articles written in Spanish and English. The journal's scope includes Computational and Numerical Models of Engineering Problems, Development and Application of Numerical Methods, Advances in Software, Computer Design Innovations, Soft Computing, Machine Learning, Artificial Intelligence, etc. RIMNI is an essential ... show more

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Comparison with Different Bayesian and non-Bayesian Estimation Techniques for the Compound Rayleigh Exponential Distribution with Actuarial Measures and Applications
I. Alkhairy, H. Alsuhabi

Rev. int. métodos numér. cálc. diseño ing. (2025). Vol. Online First, 75

Abstract
Many lifetime analysis, such as engineering, biology, survival, actuarial and medical sciences, heavily rely on the two-parameter compound Rayleigh exponential distribution, which is well-known in statistical theory. Because of their ability to successfully handle small sample sizes and involve prior knowledge, Bayesian techniques are crucial for estimating the parameters of the compound Rayleigh exponential distribution. This study presents the estimation of the compound Rayleigh exponential distribution unknown parameters using Bayesian and non-Bayesian estimation techniques, including maximum likelihood estimation, maximum product spacing, least square estimator, weighted least square estimator, Cramer-Von-Mise estimator, Anderson-Darling estimator, and Bayesian techniques with informative and non-informative priors based on different loss functions. Additionally, we used several methods to obtain the confidence intervals for the unknown parameters, such as the approximate and Bootstrap methods. The effectiveness of these estimators is evaluated through a Monte Carlo simulation study. Furthermore, we are committed to investigating three widely recognized risk metrics: the value at risk, the tail value at risk, and the tail variance premium. These findings are helpful for actuarial risk researchers who depend on risk measurement fitting when evaluating Bayesian tools for effectively modeling actuarial sciences. Finally, different applications taken from several areas are examined to illustrate the practical usefulness of the compound Rayleigh exponential distribution. Using various model selection criteria, the introduced model is contrasted with that of several well-known distributions. Our empirical findings indicate that the suggested model has superior goodness-of-fit to the other models examined.
Abstract
Many lifetime analysis, such as engineering, biology, survival, actuarial and medical sciences, heavily rely on the two-parameter compound Rayleigh exponential distribution, [...]
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Freshwater Snail Optimizer: A Bio-Inspired Optimizer for Engineering Design Problems
G. Liu, J. Pan, S. Chu, R. Wang, B. Yang, Y. Yu, S. Mirjalili

Rev. int. métodos numér. cálc. diseño ing. (2025). Vol. Online First, 85

Abstract
As the scale and nonlinearity of optimization problems continue to increase, traditional deterministic solution strategies are becoming increasingly flawed in the face of the exponential growth of search space dimensions and multimodal objective functions. Metaheuristic algorithms, with their probability-driven global search capabilities and local development capabilities, have gradually become an essential tool for solving complex optimization tasks. We propose a Freshwater Snail Optimizer (FSO), inspired by the social behavior of water snails in terms of movement and collision, as a metaheuristic algorithm. FSO combines the floating of water snails’ air chambers, movement in the water, and population collisions and divides them into groups during initialization to balance exploration and development, achieving gratifying optimization results, especially in high-dimensional problems. We utilized CEC 2017 and CEC 2022 to qualitatively analyze FSO in various problems, and employed the Friedman test and Wilcoxon rank sum test for statistical testing. Experimental results show that our proposed FSO achieved 32 first-place results on 41 problems compared with 9 classic algorithms, and 27 first-place results when compared with 9 emerging algorithms that appeared in the past two years. FSO has also achieved the first comparison results in six engineering optimizations on multiple occasions, proving that FSO possesses well optimization capabilities and practicality for real-world problems. The source code accompanying this article has been released at:https://github.com/leogalaxy0603/Freshwater-SnailOptimizer(accessed on 12 October 2025).OPEN ACCESS Received: 19/08/2025 Accepted: 13/10/2025
Abstract
As the scale and nonlinearity of optimization problems continue to increase, traditional deterministic solution strategies are becoming increasingly flawed in the face of [...]
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Study on the Annular Pressure Prediction Method for Ultra-Deep Well Hydraulic Lift Dual-Gradient Drilling
Y. Chen, J. Yuan, K. Liu, J. Zhu, M. Li, H. Wang, Y. Li

Rev. int. métodos numér. cálc. diseño ing. (2025). Vol. Online First, 86

Abstract
With the ongoing advancement of oil and gas exploration into deep and ultra-deep formations in China, precise wellbore pressure control under complex geological conditions has become a critical technical challenge for safe drilling operations. To overcome the limitations of existing dual-gradient drilling (DGD) technologies—particularly their poor applicability and limited pressure regulation capability in land-based drilling—this study introduces an innovative hydraulic-lift dual-gradient drilling annular flow model, tailored for ultra-deep vertical wells. The model accounts for solid–liquid phase separation flow characteristics and the hydraulic-lift effect of downhole dual-gradient pumps. The Stability Enhancing Two-Step (SETS) method is employed to solve the strongly nonlinear, coupled governing equations, significantly improving computational stability and efficiency. Experimental validation reveals that the model’s predicted pressure distribution closely matches measured data, with a maximum average error of only 16.4%, confirming the model’s accuracy and applicability. Additionally, this study systematically analyzes the impact of key parameters—such as drilling fluid flow rate, viscosity, lift pump speed, and the number of pump sections—on bottomhole pressure regulation, providing valuable insights into their influence on annular pressure behavior. The findings offer a solid theoretical foundation for optimizing drilling parameters and ensuring safe, efficient drilling in ultra-deep wells under challenging geological conditions.OPEN ACCESS Received: 16/07/2025 Accepted: 19/08/2025
Abstract
With the ongoing advancement of oil and gas exploration into deep and ultra-deep formations in China, precise wellbore pressure control under complex geological conditions [...]
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Qualitative Analysis of Nonlinear Systems Involving Hadamard-Type Fractional Derivatives with Nonlocal Boundary Conditions and Stability Properties
M. Manigandan, M. Awadalla, R. Shanthi, S. Trabelsi

Rev. int. métodos numér. cálc. diseño ing. (2025). Vol. Online First, 87

Abstract
This paper establishes a comprehensive analysis of a coupled system of nonlinear Hadamard-type fractional differential equations subject to generalized nonlocal integral boundary conditions. The distinct logarithmic kernel of the Hadamard derivative makes this framework particularly suitable for modeling scale-invariant processes and ultraslow diffusion phenomena. The existence and uniqueness of solutions are rigorously investigated using fixed point theory: Banach’s contraction principle ensures uniqueness, while the Leray-Schauder nonlinear alternative guarantees existence under more general growth conditions. Furthermore, the system is proven to be Ulam-Hyers stable, ensuring that approximate solutions remain close to exact solutions, which is crucial for the robustness of the model in practical applications. The theoretical findings are effectively validated through two detailed numerical examples, demonstrating the applicability of the established results to different classes of nonlinearities.OPEN ACCESS Received: 22/08/2025 Accepted: 03/11/2025
Abstract
This paper establishes a comprehensive analysis of a coupled system of nonlinear Hadamard-type fractional differential equations subject to generalized nonlocal integral boundary [...]
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A Picture Fuzzy Decision-Making Framework for COBOT Selection in Digital Supply Chains
B. Kesici

Rev. int. métodos numér. cálc. diseño ing. (2025). Vol. Online First, 88

Abstract
Driven by digitalization in supply chains, the use of Collaborative Robots (COBOTs) has become increasingly widespread in recent years. They significantly contribute to process efficiency by working in place of, or in collaboration with, humans in a variety of operations, including welding, painting, assembly and disassembly, transportation, packaging, and palletizing. However, when uncertainty and different criteria are taken into account, decision support systems that compare practical robots based on their suitability for specific needs are inadequate. This study presents a comprehensive multi-criteria decision-making (MCDM) framework for prioritizing COBOTs with different features used in digital supply chain processes. Based on in-depth research in the literature and the opinions of experts working in companies that use relevant robots in the industry, the criteria to be evaluated when selecting COBOT types are identified. The importance of these criteria was determined using the Picture Fuzzy Step-wise Weight Assessment Ratio Analysis (PiF-SWARA) method, which effectively captures the uncertainty in experts’ decisionmaking processes. Subsequently, alternative COBOT types were ranked using the Picture Fuzzy Combinative Distance-Based Assessment (PiFCODAS) approach. This case study, which evaluates the PiF-SWARACODAS concept, reveals that according to expert assessments, cost is the most important criterion in COBOT selection, followed by process quality and space utilization. The findings about the selection of types emphasize that high-efficiency articulated robots operating at high speeds under mass production conditions are the primary priority. These robots are followed by humanoid robots. The third most important are power and force-limiting robots. The fourth and fifth types of COBOTs are hand-guided and safety-monitored stop robots. Validation and sensitivity analyses confirmed the robustness of the results. Overall, the proposed framework not only clarifies the key priorities for manufacturing facilities but also provides a validated decision support tool to align digitalization strategies with the most appropriate COBOT investments.OPEN ACCESS Received: 25/08/2025 Accepted: 15/10/2025 An extensive literature review was conducted to examine previous research on COBOT applications in the supply chain, to identify evaluation criteria and alternatives for this study, and to highlight the originality of this study. The concept of COBOT was included in books, journals and conference proceedings accessible through the SCOPUS database. However, the literature search with the related keyword found too many studies. Therefore, the scope was further customized to include different types of COBOT models that can be used throughout the supply chain. To make the literature review process more systematic, the PRISMA methodology, which stands for “Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)”, was used. The PRISMA approach, designed by Moher et al. [10], has become widely used among academics in recent years. Sources are analyzed and evaluated according to the determined eligibility criteria. Then, appropriate studies are selected. Table 1lists the keywords used to perform a PRISMA method literature review, along with the number of studies found using these Table 1: Literature search with A total of 1179 studies were found in SCOPUS after searching with the were found. The results were duplicated because some
Abstract
Driven by digitalization in supply chains, the use of Collaborative Robots (COBOTs) has become increasingly widespread in recent years. They significantly contribute to process [...]
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