A novel improved elephant herding optimization for path planning of a mobile robot

Swarm intelligence algorithms have been in recent years one of the most used tools for planning the trajectory of a mobile robot. Researchers are applying those algorithms to find the optimal path, which reduces the time required to perform a task by the mobile robot. In this paper, we propose a new method based on the grey wolf optimizer algorithm (GWO) and the improved elephant herding optimization algorithm (IEHO) for planning the optimal trajectory of a mobile robot. The proposed solution consists of developing an IEHO algorithm by improving the basic EHO algorithm and then hybridizing it with the GWO algorithm to take advantage of the exploration and exploitation capabilities of both algorithms. The comparison of the IEHO-GWO hybrid proposed in this work with the GWO, EHO, and cuckoo-search (CS) algorithms via simulation shows its effectiveness in finding an optimal trajectory by avoiding obstacles around the mobile robot

Energy-Based Acoustic Localization by Improved Elephant Herding Optimization

UIDB/EEA/50008/2020The present work proposes a new approach to address the energy-based acoustic localization problem. The proposed approach represents an improved version of evolutionary optimization based on Elephant Herding Optimization (EHO), where two major contributions are introduced. Firstly, instead of random initialization of elephant population, we exploit particularities of the problem at hand to develop an intelligent initialization scheme. More precisely, distance estimates obtained at each reference point are used to determine the regions in which a source is most likely to be located. Secondly, rather than letting elephants to simply wander around in their search for an update of the source location, we base their motion on a local search scheme which is found on a discrete gradient method. Such a methodology significantly accelerates the convergence of the proposed algorithm, and comes at a very low computational cost, since discretization allows us to avoid the actual gradient computations. Our simulation results show that, in terms of localization accuracy, the proposed approach significantly outperforms the standard EHO one for low noise settings and matches the performance of an existing enhanced version of EHO (EEHO). Nonetheless, the proposed scheme achieves this accuracy with significantly less number of function evaluations, which translates to greatly accelerated convergence in comparison with EHO and EEHO. Finally, it is also worth mentioning that the proposed methodology can be extended to any population-based metaheuristic method (it is not only restricted to EHO), which tackles the localization problem indirectly through distance measurements.publishersversionpublishe

Evolutionary Computation 2020

Intelligent optimization is based on the mechanism of computational intelligence to refine a suitable feature model, design an effective optimization algorithm, and then to obtain an optimal or satisfactory solution to a complex problem. Intelligent algorithms are key tools to ensure global optimization quality, fast optimization efficiency and robust optimization performance. Intelligent optimization algorithms have been studied by many researchers, leading to improvements in the performance of algorithms such as the evolutionary algorithm, whale optimization algorithm, differential evolution algorithm, and particle swarm optimization. Studies in this arena have also resulted in breakthroughs in solving complex problems including the green shop scheduling problem, the severe nonlinear problem in one-dimensional geodesic electromagnetic inversion, error and bug finding problem in software, the 0-1 backpack problem, traveler problem, and logistics distribution center siting problem. The editors are confident that this book can open a new avenue for further improvement and discoveries in the area of intelligent algorithms. The book is a valuable resource for researchers interested in understanding the principles and design of intelligent algorithms

DFQIoV: Design of a Dynamic Fan-Shaped-Clustering Model for QoS-aware Routing in IoV Networks

Internet of Vehicles (IoV) is a steadily growing field of research that deals with highly ad-hoc wireless networks. These networks require design of high-speed & high-efficiency routing models, that can be applied to dynamically changing network scenarios. Existing models that perform this task are highly complex and require larger delays for estimation of dynamic routes. While, models that have faster performance, do not consider comprehensive parameters, which limits their applicability when used for large-scale network scenarios. To overcome these limitations, this text proposes design of a novel dynamic fan-shaped clustering model for QoS-aware routing in IoV networks. The model initially collects network information sets including node positions, & energy levels, and combines them with their temporal packet delivery & throughput performance levels. These aggregated information sets are processed via a hybrid bioinspired fan shaped clustering model, that aims at optimization of routing performance via deployment of dynamic clustering process. The model performs destination-aware routing process which assists in reducing communication redundances. This is done via a combination of Elephant Herding Optimization (EHO) with Particle Swarm Optimization (PSO), which integrates continuous learning for router level operations. The integrated model is able to reduce communication delays by 5.9%, while improving energy efficiency by 8.3%, throughput by 4.5%, and packet delivery performance by 1.4% under different network scenarios. Due to which the proposed model is capable of deployment for a wide variety of dynamic network scenarios

Bio-inspired optimization algorithms for unit test generation

Tese de Mestrado, Engenharia Informática (Engenharia de Software), 2021, Universidade de Lisboa, Faculdade de CiênciasNa sociedade atual nós estamos rodeados e usamos todo o tipo de aplicações de software. Problemas no software pode causar todo o tipo de consequências, desde pessoas não conseguirem jogar um jogo como era suposto a uma aeronave despenhar-se matando toda as pessoas a bordo. De modo a que se evite certas consequências, convém que esse software não tenha problemas e funcione como é suposto. Porém, o software é escrito por humanos pelo que está sujeito a ter erros. Para lidar com esta situação, testes de software são feitos, de modo a que se descubra e resolva os problemas no software. Testar software baseado em pesquisa é uma área de teste de software que se tem mostrado bastante bemsucedida na geração de conjuntos de teste unitários otimizados para cobertura de código. Esta abordagem usa algoritmos meta-heurísticos guiados por critérios de cobertura de código para gerar os testes. Neste estudo, foi utilizado um critério de cobertura múltiplo que é composto por oito critérios diferentes: a cobertura de linhas, cobertura de ramos, cobertura de métodos, cobertura de métodos de nível de topo sem exceção, cobertura de ramos direto, cobertura de output, mutação fraca e cobertura de exceções. No que diz respeito aos algoritmos meta-heurísticos, os algoritmos evolucionários são o estado da arte atual, tendo apresentado os melhores resultados em estudos anteriores, superando os algoritmos aleatórios. No entanto, serão os algoritmos evolucionários realmente os melhores algoritmos neste contexto? E quanto aos algoritmos de inteligência de grupo, poderão eles também apresentar bons resultados? Poderá o atual estado da arte ser substituído por um algoritmo de inteligência de grupo? Deste modo, para responder a estas e outras questões, decidimos explorar os algoritmos bio-inspirados, também conhecidos por algoritmos de inteligência de grupo. Estes algoritmos baseiam-se no comportamento de indivíduos que pertencem a grupos na natureza, tais como os enxames de abelhas. Os algoritmos bio-inspirados não são completamente novos na área de testar software. Estudos anteriores mostram que os algoritmos de inteligência de grupo são geralmente melhores que os algoritmos genéticos para testes de estrutura, que na geração de dados para testes o desempenho dos algoritmos depende do tipo de problema e que na geração automática de testes Artificial Bee Algorithm teve o melhor desempenho e o Bat Algorithm é o mais rápido a executar. Nós escolhemos implementar dez algoritmos de inteligência de grupo que possuem várias características diferentes, com diferentes graus de popularidade e que incluem algoritmos antigos e recentes. Os algoritmos escolhidos são: Genetic Bee Colony (GBC) Algorithm, Fish Swarm Algorithm (FSA), Cat Swarm Optimization (CSO), Whale Optimization Algorithm (WOA), Artificial Algae Algorithm (AAA), Elephant Herding Optimization (EHO), Chicken Swarm Optimization Algorithm (CSOA), Moth Flame Optimization (MFO) Algorithm, Grey Wolf Optimization (GWO) Algorithm and Particle Swarm Optimizer (PSO). Para representar os algoritmos evolucionários e servir de comparação contra os algoritmos de inteligência de grupo, escolhemos o Standard Genetic Algorithm (Standard GA), Many-Objective Sorting Algorithm (MOSA) e o Dynamic ManyObjective Sorting Algorithm (DynaMOSA). Este último é o estado da arte atual. Além destes algoritmos, foi implementado mais um algoritmo que é um híbrido (fusão de algoritmos de inteligência de grupo e evolucionários), o Elephant Dynamic Many-Objective Sorting Algorithm (Elephant-DynaMOSA). O EvoSuite foi a ferramenta de geração de testes escolhida para implementar o híbrido e os dez algoritmos de inteligência de grupo por já possuir diversas otimizações, os algoritmos evolucionários já estão implementados e a natureza modular da ferramenta permite facilmente adicionar novos algoritmos ao módulo dos algoritmos. O estudo empírico realizado consiste em duas experiências: a calibração dos parâmetros e a avaliação dos algoritmos. Na primeira experiência, escolhemos vários parâmetros e testámos vários valores destes para cada algoritmo. Foi selecionado um subconjunto de 34 classes e testou-se em 30 seeds diferentes durante 60 segundos para se obter os resultados de cada configuração. De seguida, aplicámos o método estatístico Vargha-Delaney de modo a encontrar a melhor configuração de cada algoritmo. A segunda experiência consistiu em correr a melhor configuração de cada algoritmo em 312 classes com 30 seeds durante 60 segundos. Depois, com o intuito de interpretar os resultados obtidos e conseguir ver qual o melhor algoritmo de inteligência de grupo, se os algoritmos de inteligência de grupo são melhores que os três algoritmos evolucionários e quão boa é a performance do algoritmo híbrido, foram usados os métodos estatísticos de Vargha-Delaney e teste de Friedman. Também se observou a relação entre diversos aspetos dos resultados: a cobertura e o número de gerações, cobertura e a pontuação de mutação, cobertura e diversidade e cobertura e tamanho dos testes. Os nossos resultados revelam que EHO foi o melhor algoritmo de inteligência de grupo e que também superou o Standard GA. Porém, tanto DynaMOSA e MOSA mostram-se superior ao EHO. Em relação ao Elephant-DynaMOSA, que é o híbrido do melhor algoritmo de inteligência de grupo e evolucionário, os resultados foram melhores que o EHO, visto que tem um desempenho semelhante ao MOSA. No final, DynaMOSA foi o algoritmo com maior cobertura média e com os melhores resultados estatísticos nos dois métodos usados. Posteriormente, decidimos discutir outras particularidades dos resultados e propusemos três hipóteses: o melhor algoritmo é superior em todas as classes, qualquer algoritmo consegue atingir pelo menos 50% de cobertura em todas as classes e o desempenho aumenta se o tempo de execução aumentar. A primeira hipótese provou-se falsa visto que houve seis algoritmos estatisticamente melhor que os outros em certas classes: Standard GA, MOSA, DynaMOSA, EHO, Elephant-DynaMOSA e FSA. Isto foi provado ao mostrar-se os valores médios de vários aspetos obtidos nas execuções (número de gerações e testes, tamanho dos testes e cobertura), os resultados do método estatístico Vargha-Delaney e o desempenho de cada algoritmo por critério de cobertura de código. A segunda hipótese também se provou falsa porque 17.5% das classes obtiveram menos de 50% de cobertura independentemente do algoritmo usado. Uma das principais razões é a limitação do EvoSuite como ferramenta de testes, por exemplo não conseguir gerar os inputs necessários para correr a classe. A última hipótese foi a única que se provou ser verdadeira. Para responder a esta hipótese, selecionados a melhor configuração por algoritmo e correu-se 312 classes em uma seed durante uma hora. A cobertura média de todos os algoritmos subiu cerca de 7% e 13 dos 14 algoritmos melhoraram a sua cobertura. Também observámos a evolução dos algoritmos durante a execução e apenas uma minoria dos algoritmos mostrou uma melhoria significativa no desempenho após 60 segundos. Por isso, concluiu-se que apesar da melhoria geral no desempenho, tal melhoria poderá não valer a pena devido ao aumento de recursos necessários com um maior orçamento de tempo. Com isto podemos concluir que apesar do DynaMOSA manter-se como o estado da arte, ele não é o melhor em todas as situações. E que os algoritmos de inteligência de grupo mostraram um certo grau de potencial, principalmente o algoritmo híbrido, Elephant-DynaMOSA. Por isso, nós sugerimos que para trabalho futuro se teste mais algoritmos de inteligência de grupo e algoritmos de múltiplos objetivos, com foco em algoritmos híbridos que combinem os melhores aspetos dos vários algoritmos. Outra iniciativa que pode ser realizada é analisar que algoritmos são melhores para cada critério de cobertura e criar um algoritmo múltiplo capaz de se adaptar e otimizar a procura tendo em conta os critérios de cobertura escolhidos.Search-based software testing is an area of software testing that has shown to be quite successful in generating unit test suites optimized for code coverage. This approach uses meta-heuristic algorithms guided by code coverage criteria (e.g., branch coverage) to generate the tests. When it comes to meta-heuristic algorithms, evolutionary algorithms are the current state-of-the-art, having presented the best results in previous studies. However, are evolutionary algorithms truly the best algorithms in this context? What about bio-inspired algorithms, can they also present good results? Will the current state-of-the-art be replaced with a bio-inspired algorithm? In order to answer these and other questions, we performed an empirical study where we evaluated ten bio-inspired algorithms, three evolutionary algorithms and one hybrid algorithm (a mix of bio-inspired and evolutionary algorithms) on a selection of non-trivial open-source classes. EvoSuite was the test generation tool chosen to implement the ten bio-inspired algorithms and the hybrid since it already has several optimizations and the evolutionary algorithms implemented. Our results show that the Elephant Herding Optimization has the best performance among the bio-inspired algorithms and has surpassed the Standard Genetic Algorithm. However, both the Many-Objective Sorting Algorithm (MOSA) and the Dynamic Many Objective Sorting Algorithm (DynaMOSA) showed superior efficiency compared to all ten bio-inspired algorithms. When it comes to the hybrid algorithm, Elephant Dynamic Many-Objective Sorting Algorithm (Elephant-DynaMOSA), it ended up with a similar performance to MOSA but still worse than the current state-of-the-art, DynaMOSA. We also discussed three hypotheses about the results obtained. Although DynaMOSA remains the state-of-the-art algorithm, it is not the best in all classes. Not only so, but the bio-inspired algorithms showed some potential, especially in the case of the hybrid, Elephant-DynaMOSA. Thus, we suggest future work on hybrid algorithms that fuse the best aspects of several algorithms

Microphone Array Speech Enhancement Via Beamforming Based Deep Learning Network

In general, in-car speech enhancement is an application of the microphone array speech enhancement in particular acoustic environments. Speech enhancement inside the moving cars is always an interesting topic and the researchers work to create some modules to increase the quality of speech and intelligibility of speech in cars. The passenger dialogue inside the car, the sound of other equipment, and a wide range of interference effects are major challenges in the task of speech separation in-car environment. To overcome this issue, a novel Beamforming based Deep learning Network (Bf-DLN) has been proposed for speech enhancement. Initially, the captured microphone array signals are pre-processed using an Adaptive beamforming technique named Least Constrained Minimum Variance (LCMV). Consequently, the proposed method uses a time-frequency representation to transform the pre-processed data into an image. The smoothed pseudo-Wigner-Ville distribution (SPWVD) is used for converting time-domain speech inputs into images. Convolutional deep belief network (CDBN) is used to extract the most pertinent features from these transformed images. Enhanced Elephant Heard Algorithm (EEHA) is used for selecting the desired source by eliminating the interference source. The experimental result demonstrates the effectiveness of the proposed strategy in removing background noise from the original speech signal. The proposed strategy outperforms existing methods in terms of PESQ, STOI, SSNRI, and SNR. The PESQ of the proposed Bf-DLN has a maximum PESQ of 1.98, whereas existing models like Two-stage Bi-LSTM has 1.82, DNN-C has 1.75 and GCN has 1.68 respectively. The PESQ of the proposed method is 1.75%, 3.15%, and 4.22% better than the existing GCN, DNN-C, and Bi-LSTM techniques. The efficacy of the proposed method is then validated by experiments

Hybrid Optimization Based Hindi Document Summarization Using Deep Learning Technique

The proliferation of textual information today is a result of the internet's recent development, which is widely accessible to anybody, at any time. Generally speaking, several Natural Language Processing (NLP) techniques can be used to analyze the textual information that is offered on the basis of text documents. In recent years, various text summarization techniques have been implemented in English text documents but a little amount of work is carried out in Hindi text documents summarization. In this research investigation, the Coot Remora Optimization (CRO) technique based on Deep Recurrent Neural Network (DRNN) is used to summarize Hindi documents. Here, the CRO algorithm is used to train the DRNN, which is used to compute the sentence scores.The highest scored sentences are going to included in the summary. When compared to recent optimization algorithmic techniques, such as MCRMR-SSO, Graph-based_PSO, Genetic Algorithms (GA), and Political Elephant Herding Optimization (PEHO) based Deep Long Short Term Memory (DLSTM) algorithm, the developed method is shown to be superior. Additionally, three evaluation metrics such as precision, recall, f-measure are used to analyze the performance of the CRO based DRNN technique and obtained high performance

Voltage Profile improvement by optimal DG allocation using atom search optimisation in radial and mesh distribution system

Recent years have seen a considerable increase in the generation of power using renewable energy sources. This paper deals with the allocation of distributed generations (DG) in radial as well as mesh distribution network (RDSm&MDSm, respectively). The allocation of DG is been done through a meta-heuristic technique known as Atom Search Optimisation. In the paper, the power loss is reduced, along with simultaneous improvement of voltage profile of the system. The proposed algorithm has been tested on IEEE 33 & 69 radial and weakly meshed system with 5 tie lines is considered for power loss minimisation using single and multiple DGs. Two power factors are considered for the simulation 0.8 lag and 0.9 pf lag. The simulation results are carried out in MATLAB

Power Management in Hybrid ANFIS PID Based AC–DC Microgrids with EHO Based Cost Optimized Droop Control Strategy

One of the most critical operations aspects is power management strategies for hybrid AC/DC microgrids. This work presented power management in hybrid AC–DC microgrids with a droop control strategy. At first, photovoltaic, Wind, and battery are used as the power sources, which supply the power with uncertainties. The AC and DC microgrids are controlled by an Adaptive neuro-fuzzy inference system (ANFIS) controller and Proportional Integral Derivative (PID) controller. Simultaneously we calculate the running cost for photovoltaic, Wind, and Battery. Moreover, an optimizer based on the elephant herding optimization algorithm is formulated to reduce the cost price. This method utilizes two stages like clan updating operator and separating operator. This cost value is used to calculate the Droop Coefficients in Droop Control Strategy. The autonomous droop control strategy is utilized in the interlinking converter to share the load between AC and DC. This proposed concept is implemented in the MATLAB tool, and the performance is taken in terms of voltage, power, and current for PV and wind, DC link voltage and load current. The bidirectional ac/dc interlinking converter power flow was subsequently changed from 2.2k W to −2k W. The effectiveness of the power dispatch mode under uniform control has been verified