In Open Radio Access Network (O-RAN), intelligent techniques are urged to achieve the automation of the computing resource allocation, so as to save computing resources and increase their utilization rate, as well as ...
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In Open Radio Access Network (O-RAN), intelligent techniques are urged to achieve the automation of the computing resource allocation, so as to save computing resources and increase their utilization rate, as well as decrease the network delay. However, the existing formulation of this problem as an optimization problem defines the capacity utility of resource in an inappropriate way and it tends to cause much delay. Moreover, the only algorithm proposed to solve this problem is a greedy search algorithm, which is not ideal as it could get stuck into local optima. To overcome these issues, a new formulation that better describes the problem is proposed. In addition, an evolutionary algorithm (EA) is designed to find a resource allocation scheme to proactively and dynamically deploy the computing resource for processing upcoming traffic data. A multivariate long short-term memory model is used in the proposed EA to predict future traffic data for the production of deployment scheme. As a global search approach, the EA is less likely to get stuck in local optima than greed search, leading to better solutions. Experimental studies carried out on real-world datasets and artificially generated datasets with different scenarios and properties have demonstrated the significant superiority of our proposed EA over a baseline greedy algorithm under all parameter settings. Moreover, experimental studies with all afore-mentioned datasets are performed to compare the proposed EA and two variants under different parameter settings, to demonstrate the impact of different algorithm choices.
Multiobjective evolutionary algorithms (MOEAs) face significant challenges when addressing dynamic multiobjective optimization problems, particularly those with frequent changes. The complexity of dynamic environments...
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Multiobjective evolutionary algorithms (MOEAs) face significant challenges when addressing dynamic multiobjective optimization problems, particularly those with frequent changes. The complexity of dynamic environments makes it difficult for MOEAs to accurately approximate the true Pareto-optimal solutions before subsequent changes occur. Typically, historical approximations of Pareto-optimal solutions are utilized to predict solutions in future environments. However, existing predictors often overlook the nondeterministic nature of historical solutions, potentially compromising prediction accuracy. In this paper, we propose a novel predictor based on Gaussian Process Regression (GPR) for evolutionary dynamic multiobjective optimization. Unlike traditional deterministic predictors, our approach aims to provide a probability distribution of predicted results, thereby addressing the inherent nondeterminism of historical solutions. We employ GPR to model relationships among historical solutions across different time steps. Within the framework of the classical MOEA, MOEA/D, we introduce a new method MOEA/D-GPR for evolutionary Dynamic Multiobjective Optimization (EDMO). Experimental results demonstrate that our method achieves state-of-the-art performance.
The research work on optimization has witnessed significant growth in the past few years, particularly within multi- and single-objective optimization algorithm areas. This study provides a comprehensive overview and ...
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The research work on optimization has witnessed significant growth in the past few years, particularly within multi- and single-objective optimization algorithm areas. This study provides a comprehensive overview and critical evaluation of a wide range of optimization algorithms from conventional methods to innovative metaheuristic techniques. The methods used for analysis include bibliometric analysis, keyword analysis, and content analysis, focusing on studies from the period 2000-2023. Databases such as IEEE Xplore, SpringerLink, and ScienceDirect were extensively utilized. Our analysis reveals that while traditional algorithms like evolutionary optimization (EO) and particle swarm optimization (PSO) remain popular, newer methods like the fitness-dependent optimizer (FDO) and learner performance-based behavior (LPBB) are gaining attraction due to their adaptability and efficiency. The main conclusion emphasizes the importance of algorithmic diversity, benchmarking standards, and performance evaluation metrics, highlighting future research paths including the exploration of hybrid algorithms, use of domain-specific knowledge, and addressing scalability issues in multi-objective optimization.
Vehicle-edge computing, as a promising paradigm, is employed to support applications that require low latency and high computational capability. In this study, we consider the idle resources of the surrounding parked ...
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Vehicle-edge computing, as a promising paradigm, is employed to support applications that require low latency and high computational capability. In this study, we consider the idle resources of the surrounding parked vehicles (PVs) and roadside units (RSUs) as service providers to enhance the performance of User Equipment (UE). We propose a joint offloading architecture that uses parked vehicles. Additionally, owing to the dynamic and uncertain nature of the environment, we model computation offloading as a dynamic multi-objective optimization problem to simultaneously optimize the latency and energy consumption of UE applications. In this study, we propose a dynamic multi-objective evolutionary algorithm with a multi-strategy fusion response (DMOEA/D-MSFR). Specifically, we introduce a population center positioning strategy and a learnable prediction mechanism using Long Short-Term Memory (LSTM) in DMOEA-MSFR, which divides the prediction optimization process into two stages and exhibits a rapid response to environmental changes. In the static optimization phase, an adaptive weight vector adjustment strategy is employed, which significantly aids in the distribution and diversity of the solutions. Comprehensive experiments demonstrate that our proposed framework balances the trade-off between latency and energy consumption, and the convergence, feasibility, and diversity of the non-dominated solutions obtained.
In real-world scenarios where resources for evaluating expensive optimization problems are limited and the reliability of trained models is hard to assess, the quality of the non-dominated front formed by algorithms t...
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In real-world scenarios where resources for evaluating expensive optimization problems are limited and the reliability of trained models is hard to assess, the quality of the non-dominated front formed by algorithms tends to below. This paper proposes a metric-based surrogate-assisted evolutionary algorithm for multi-objective expensive optimization, incorporating a novel model management strategy that integrates a regeneration mechanism. This approach aims to achieve a well-balanced convergence and diversity, facilitating the attainment of high-quality non-dominated fronts to address expensive multi-objective optimization problems. The model management strategy, based on metrics, comprehensively evaluates the reliability of the classification model and selects appropriate strategies for offspring selection. Moreover, through significance analysis of the population, the regeneration mechanism identifies high-quality dimensions for regenerating offspring. The algorithm maximizes the utilization of the classification model to guide the generation and selection of offspring in the population. Experiments on DTLZ, MaF, WFG, and the high-dimensional portfolio optimization problem demonstrate that the proposed algorithm outperforms nine state-of-the-art surrogate-assisted evolutionary algorithms, highlighting its superior performance across various scenarios.
Permanent Magnet Synchronous Machines (PMSMs) have revolutionized motor design by replacing traditional components like rotor windings, brushes, and sliding contacts with permanent magnets. This innovation has signifi...
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Permanent Magnet Synchronous Machines (PMSMs) have revolutionized motor design by replacing traditional components like rotor windings, brushes, and sliding contacts with permanent magnets. This innovation has significantly improved operational efficiency and reduced maintenance needs. However, controlling PMSMs remains challenging due to the changing dynamics of the machine over time and its sensitivity to different environmental conditions. To tackle these challenges, this study presents a novel nonlinear control approach called passivity-based control (PBC). Unlike conventional methods, PBC manages both the electrical and mechanical dynamics of the system, focusing on energy flow and dissipation to maintain stability. To make the control more robust, the approach combines a nonlinear observer and a high-order sliding mode controller (HSMC), which enhance the system's ability to handle disturbances and parameter changes. Additionally, the study uses Genetic Algorithm (GA) optimization to fine-tune the parameters of the PBC, observer, and HSMC. This optimization improves the motor's tracking accuracy and robustness against external disruptions. The result is a control framework that preserves the natural dynamics of PMSMs while improving their stability and performance. Experimental validation using the platform for real-time simulation (OPAL-RT) and real world on a PMSM using dSPACE DS1202 board demonstrates that this method outperforms existing techniques under a variety of operating conditions, highlighting its effectiveness and reliability.
In this work, we propose a method for solving large-scale multi-objective problems based on problem transformation strategy. The key point of this method lies in how to construct the search subspace. First, the algori...
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In this work, we propose a method for solving large-scale multi-objective problems based on problem transformation strategy. The key point of this method lies in how to construct the search subspace. First, the algorithm obtains a set of direction vectors in the decision space, which are combined in pairs to construct a set of subspaces. To obtain direction vectors with a uniform distribution as much as possible, we introduce the opposition-based learning strategy. Then, based on these subspaces, the original high-dimensional problem is transformed into a relatively lower-dimensional problem. A multi-objective evolutionary algorithm is used to quickly obtain a set of quasi-optimal solutions for the transformed lower-dimensional problem, and this set of solutions is further optimized in the original high-dimensional decision space. To validate its performance, the proposed algorithm is compared with six state-of-the-art large-scale multi-objective algorithms on various benchmark test problems, including one practical application. The experimental results demonstrate that the proposed algorithm shows competitive performance for dealing with large-scale multi-objective optimization problems.
Neural architecture search (NAS) has emerged as a powerful method for automating neural network design, yet its high computational cost remains a significant challenge. This paper introduces hybrid training-less neura...
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Neural architecture search (NAS) has emerged as a powerful method for automating neural network design, yet its high computational cost remains a significant challenge. This paper introduces hybrid training-less neural architecture search (HYTES-NAS), a novel hybrid NAS framework that integrates evolutionary computation with a training-free evaluation strategy, significantly reducing computational demands while maintaining high search efficiency. Unlike conventional NAS methods that rely on full model training, HYTES-NAS leverages a surrogate-assisted scoring mechanism to assess candidate architectures efficiently. Additionally, a smart-block discovery strategy and particle swarm optimisation are employed to refine the search space and accelerate convergence. Experimental results on multiple NAS benchmarks demonstrate that HYTES-NAS achieves superior performance with significantly lower computational cost compared to state-of-the-art NAS methods. This work provides a promising and scalable solution for efficient NAS, making high-performance architecture search more accessible for real-world applications.
This paper presents a novel classification algorithm for multi-omics data, called evolutionary Multi-Test Tree with Relative Expression (EMTTree+RX). The innovation lies in the model's design, which integrates mul...
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This paper presents a novel classification algorithm for multi-omics data, called evolutionary Multi-Test Tree with Relative Expression (EMTTree+RX). The innovation lies in the model's design, which integrates multi-test decision nodes with Relative Expression Analysis (RXA). Each decision node combines traditional univariate tests and top-scoring pair (TSP) comparisons, allowing the algorithm to capture complex relationships between features without relying solely on absolute values. This approach enables the proposed method to detect subtle patterns across various omics layers while maintaining a high level of interpretability, a feature crucial for clinical and bioinformatics applications. The tree structure is induced through evolutionary algorithms (EA), optimizing both the global architecture and local multi-test nodes to balance classification accuracy, test diversity, and feature cost. Applied to large-scale multi-omics datasets, where conventional decision tree methods often struggle with underfitting or overfitting, the proposed method consistently outperforms traditional models in terms of accuracy and transparency. This makes it a valuable tool for precision medicine and multi-modal data integration.
As an optimization problem, the main challenges in the enhancement of dental X-ray images are to perform the tasks of edge detection, noise removal and brightness adjustment in a precise and efficient manner. To overc...
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As an optimization problem, the main challenges in the enhancement of dental X-ray images are to perform the tasks of edge detection, noise removal and brightness adjustment in a precise and efficient manner. To overcome these challenges, designing an optimization algorithm that exhibits exploit-exploit behavior in accordance with the geometric structure of the search space of dental images is an important challenge that has not yet been realized. Shortcomings in this area lead to local solution traps and early convergence problems in image enhancement algorithms. This paper introduces the dFDB-LSHADE (dynamic fitness-distance balance-based achievement-history-based adaptive differential evolution with linear population size reduction) algorithm, which is designed for the enhancement of dental X-ray images according to the requirements of the search space of this problem and dynamically changes its exploitation-exploration capabilities. The proposed method is tested on a dataset of 120 periapical images, the most extensive experimental study in the literature. A total of 60 competing algorithms, 53 heuristics and 7 deterministic-based algorithms, were used in the experiments. In the study on dental images, the proposed algorithm has a better Friedman score than all competitors. According to the statistical analysis results obtained from the Wilcoxon pairwise test, the proposed dFDB-LSHADE was able to find better solutions for 23.3% of the images compared to its strongest competitor on the dental image set.
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