561 research outputs found
A Hybrid Chimp Optimization Algorithm and Generalized Normal Distribution Algorithm with Opposition-Based Learning Strategy for Solving Data Clustering Problems
This paper is concerned with data clustering to separate clusters based on
the connectivity principle for categorizing similar and dissimilar data into
different groups. Although classical clustering algorithms such as K-means are
efficient techniques, they often trap in local optima and have a slow
convergence rate in solving high-dimensional problems. To address these issues,
many successful meta-heuristic optimization algorithms and intelligence-based
methods have been introduced to attain the optimal solution in a reasonable
time. They are designed to escape from a local optimum problem by allowing
flexible movements or random behaviors. In this study, we attempt to
conceptualize a powerful approach using the three main components: Chimp
Optimization Algorithm (ChOA), Generalized Normal Distribution Algorithm
(GNDA), and Opposition-Based Learning (OBL) method. Firstly, two versions of
ChOA with two different independent groups' strategies and seven chaotic maps,
entitled ChOA(I) and ChOA(II), are presented to achieve the best possible
result for data clustering purposes. Secondly, a novel combination of ChOA and
GNDA algorithms with the OBL strategy is devised to solve the major
shortcomings of the original algorithms. Lastly, the proposed ChOAGNDA method
is a Selective Opposition (SO) algorithm based on ChOA and GNDA, which can be
used to tackle large and complex real-world optimization problems, particularly
data clustering applications. The results are evaluated against seven popular
meta-heuristic optimization algorithms and eight recent state-of-the-art
clustering techniques. Experimental results illustrate that the proposed work
significantly outperforms other existing methods in terms of the achievement in
minimizing the Sum of Intra-Cluster Distances (SICD), obtaining the lowest
Error Rate (ER), accelerating the convergence speed, and finding the optimal
cluster centers.Comment: 48 pages, 14 Tables, 12 Figure
Chaos embedded opposition based learning for gravitational search algorithm
Due to its robust search mechanism, Gravitational search algorithm (GSA) has
achieved lots of popularity from different research communities. However,
stagnation reduces its searchability towards global optima for rigid and
complex multi-modal problems. This paper proposes a GSA variant that
incorporates chaos-embedded opposition-based learning into the basic GSA for
the stagnation-free search. Additionally, a sine-cosine based chaotic
gravitational constant is introduced to balance the trade-off between
exploration and exploitation capabilities more effectively. The proposed
variant is tested over 23 classical benchmark problems, 15 test problems of CEC
2015 test suite, and 15 test problems of CEC 2014 test suite. Different
graphical, as well as empirical analyses, reveal the superiority of the
proposed algorithm over conventional meta-heuristics and most recent GSA
variants.Comment: 33 pages, 5 Figure
A Comprehensive Survey on Particle Swarm Optimization Algorithm and Its Applications
Particle swarm optimization (PSO) is a heuristic global optimization method, proposed originally by Kennedy and Eberhart in 1995. It is now one of the most commonly used optimization techniques. This survey presented a comprehensive investigation of PSO. On one hand, we provided advances with PSO, including its modifications (including quantum-behaved PSO, bare-bones PSO, chaotic PSO, and fuzzy PSO), population topology (as fully connected, von Neumann, ring, star, random, etc.), hybridization (with genetic algorithm, simulated annealing, Tabu search, artificial immune system, ant colony algorithm, artificial bee colony, differential evolution, harmonic search, and biogeography-based optimization), extensions (to multiobjective, constrained, discrete, and binary optimization), theoretical analysis (parameter selection and tuning, and convergence analysis), and parallel implementation (in multicore, multiprocessor, GPU, and cloud computing forms). On the other hand, we offered a survey on applications of PSO to the following eight fields: electrical and electronic engineering, automation control systems, communication theory, operations research, mechanical engineering, fuel and energy, medicine, chemistry, and biology. It is hoped that this survey would be beneficial for the researchers studying PSO algorithms
Investigation of Different Optimization Techniques for Rectenna
Rectenna optimization is important for increasing the efficiency and power output of devices that convert radio frequency (RF) energy into DC power. This can be accomplished by optimizing the design and components used in the rectenna, as well as changing the operating frequency and input power level. Optimization algorithms in rectenna design aid in determining the required geometry parameters of the antenna and rectifier, as well as to find the optimal values of passive components used in the design. This paper investigates various algorithms and optimizers based on these which are used for rectenna optimization
Evolving CNN-LSTM Models for Time Series Prediction Using Enhanced Grey Wolf Optimizer
In this research, we propose an enhanced Grey Wolf Optimizer (GWO) for designing the evolving Convolutional Neural Network-Long Short-Term Memory (CNN-LSTM) networks for time series analysis. To overcome the probability of stagnation at local optima and a slow convergence rate of the classical GWO algorithm, the newly proposed variant incorporates four distinctive search mechanisms. They comprise a nonlinear exploration scheme for dynamic search territory adjustment, a chaotic leadership dispatching strategy among the dominant wolves, a rectified spiral local exploitation action, as well as probability distribution-based leader enhancement. The evolving CNN-LSTM models are subsequently devised using the proposed GWO variant, where the network topology and learning hyperparameters are optimized for time series prediction and classification tasks. Evaluated using a number of benchmark problems, the proposed GWO-optimized CNN-LSTM models produce statistically significant results over those from several classical search methods and advanced GWO and Particle Swarm Optimization variants. Comparing with the baseline methods, the CNN-LSTM networks devised by the proposed GWO variant offer better representational capacities to not only capture the vital feature interactions, but also encapsulate the sophisticated dependencies in complex temporal contexts for undertaking time-series tasks
A Tent L\'evy Flying Sparrow Search Algorithm for Feature Selection: A COVID-19 Case Study
The "Curse of Dimensionality" induced by the rapid development of information
science, might have a negative impact when dealing with big datasets. In this
paper, we propose a variant of the sparrow search algorithm (SSA), called Tent
L\'evy flying sparrow search algorithm (TFSSA), and use it to select the best
subset of features in the packing pattern for classification purposes. SSA is a
recently proposed algorithm that has not been systematically applied to feature
selection problems. After verification by the CEC2020 benchmark function, TFSSA
is used to select the best feature combination to maximize classification
accuracy and minimize the number of selected features. The proposed TFSSA is
compared with nine algorithms in the literature. Nine evaluation metrics are
used to properly evaluate and compare the performance of these algorithms on
twenty-one datasets from the UCI repository. Furthermore, the approach is
applied to the coronavirus disease (COVID-19) dataset, yielding the best
average classification accuracy and the average number of feature selections,
respectively, of 93.47% and 2.1. Experimental results confirm the advantages of
the proposed algorithm in improving classification accuracy and reducing the
number of selected features compared to other wrapper-based algorithms
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