scholarly journals Application and Development of Enhanced Chaotic Grasshopper Optimization Algorithms

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Akash Saxena ◽  
Shalini Shekhawat ◽  
Rajesh Kumar
Keyword(s):  
Optimization Problem ◽  
Chaotic Maps ◽  
Optimization Algorithms ◽  
Exploration And Exploitation ◽  
Parameter Estimation Problem ◽  
Wilcoxon Rank Sum Test ◽  
The World ◽  
Grasshopper Optimization ◽  
Two Phases ◽  
Truss Design Problem

In recent years, metaheuristic algorithms have revolutionized the world with their better problem solving capacity. Any metaheuristic algorithm has two phases: exploration and exploitation. The ability of the algorithm to solve a difficult optimization problem depends upon the efficacy of these two phases. These two phases are tied with a bridging mechanism, which plays an important role. This paper presents an application of chaotic maps to improve the bridging mechanism of Grasshopper Optimisation Algorithm (GOA) by embedding 10 different maps. This experiment evolves 10 different chaotic variants of GOA, and they are named as Enhanced Chaotic Grasshopper Optimization Algorithms (ECGOAs). The performance of these variants is tested over ten shifted and biased unimodal and multimodal benchmark functions. Further, the applications of these variants have been evaluated on three-bar truss design problem and frequency-modulated sound synthesis parameter estimation problem. Results reveal that the chaotic mechanism enhances the performance of GOA. Further, the results of the Wilcoxon rank sum test also establish the efficacy of the proposed variants.

scholarly journals Uncovering two phases of early intercontinental COVID-19 transmission dynamics

2020 ◽  
Vol 27 (8) ◽  
Author(s):  
Jing Yang ◽  
Juan Li ◽  
Shengjie Lai ◽  
Corrine W Ruktanonchai ◽  
Weijia Xing ◽  
...  
Keyword(s):  
Phylogenetic Analyses ◽  
International Travel ◽  
Contact Tracing ◽  
Genetic Sequencing ◽  
Response Strategies ◽  
The World ◽  
Containment Measures ◽  
The Usa ◽  
Community Transmission ◽  
Two Phases

Abstract Background The COVID-19 pandemic has posed an ongoing global crisis, but how the virus spread across the world remains poorly understood. This is of vital importance for informing current and future pandemic response strategies. Methods We performed two independent analyses, travel network-based epidemiological modelling and Bayesian phylogeographic inference, to investigate the intercontinental spread of COVID-19. Results Both approaches revealed two distinct phases of COVID-19 spread by the end of March 2020. In the first phase, COVID-19 largely circulated in China during mid-to-late January 2020 and was interrupted by containment measures in China. In the second and predominant phase extending from late February to mid-March, unrestricted movements between countries outside of China facilitated intercontinental spread, with Europe as a major source. Phylogenetic analyses also revealed that the dominant strains circulating in the USA were introduced from Europe. However, stringent restrictions on international travel across the world since late March have substantially reduced intercontinental transmission. Conclusions Our analyses highlight that heterogeneities in international travel have shaped the spatiotemporal characteristics of the pandemic. Unrestricted travel caused a large number of COVID-19 exportations from Europe to other continents between late February and mid-March, which facilitated the COVID-19 pandemic. Targeted restrictions on international travel from countries with widespread community transmission, together with improved capacity in testing, genetic sequencing and contact tracing, can inform timely strategies for mitigating and containing ongoing and future waves of COVID-19 pandemic.

scholarly journals Predicting Compressive Strength of Concrete Containing Recycled Aggregate Using Modified ANN with Different Optimization Algorithms

2021 ◽  
Vol 11 (2) ◽  
pp. 485
Author(s):  
Amirreza Kandiri ◽  
Farid Sartipi ◽  
Mahdi Kioumarsi
Keyword(s):  
Compressive Strength ◽  
Optimization Algorithms ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Tree Model ◽  
Grasshopper Optimization Algorithm ◽  
Compressive Strength Of Concrete ◽  
Grasshopper Optimization ◽  
Artificial Neural Network Ann ◽  
Industry Needs

Using recycled aggregate in concrete is one of the best ways to reduce construction pollution and prevent the exploitation of natural resources to provide the needed aggregate. However, recycled aggregates affect the mechanical properties of concrete, but the existing information on the subject is less than what the industry needs. Compressive strength, on the other hand, is the most important mechanical property of concrete. Therefore, having predictive models to provide the required information can be helpful to convince the industry to increase the use of recycled aggregate in concrete. In this research, three different optimization algorithms including genetic algorithm (GA), salp swarm algorithm (SSA), and grasshopper optimization algorithm (GOA) are employed to be hybridized with artificial neural network (ANN) separately to predict the compressive strength of concrete containing recycled aggregate, and a M5P tree model is used to test the efficiency of the ANNs. The results of this study show the superior efficiency of the modified ANN with SSA when compared to other models. However, the statistical indicators of the hybrid ANNs with SSA, GA, and GOA are so close to each other.

Nanocomposites: Retrospecr and Prospect

1992 ◽  
Vol 286 ◽  
Author(s):  
Rustum Roy
Keyword(s):  
Major Part ◽  
Size Range ◽  
Nanocomposite Materials ◽  
One Dimension ◽  
New Materials ◽  
Infinite Class ◽  
Materials Synthesis ◽  
The World ◽  
Two Phases ◽  
Nanometer Size Range

ABSTRACTIn this paper we make clear distinctions from the terms nanophase, nanocrystalline and deal only with nanocomposites defined as an interacting mixture of two phases, one of which is in the nanometer size range in at least one dimension. The author's origins of development of the idea that nanocomposites are a virtually infinite class of new materials are described.Then we refer to the results of our extensive studies of nanocomposites derived by solution-solgel techniques to illustrate the properties of such materials in the area of chemical and thermal reactivity.Finally it is pointed out that in the last few years nanocomposite materials have become a major part of new materials synthesis all over the world for applications ranging from mechanical to optical, to magnetic to dielectric.

Coin Circulation in the Balkans in Late Antiquity

2007 ◽  
Author(s):  
P. GUEST
Keyword(s):  
Late Antiquity ◽  
Careful Analysis ◽  
Historical Narrative ◽  
The Balkans ◽  
Notable Feature ◽  
Starting Point ◽  
The World ◽  
Two Phases ◽  
Archaeological Excavations ◽  
Early Byzantine

The archaeological excavations carried out on late Roman and early Byzantine sites in the Balkans has revolutionized our knowledge of this part of the world in Late Antiquity. How these sites are dated is obviously important as, without accurate and reliable dating, it is difficult to understand how they fit into the wider historical narrative. This chapter takes the coins excavated at Dichin as its starting point and, by careful analysis, proposes a general dating scheme for the two phases of occupation at the settlement. The lack of coins struck during the years 474–518 is a notable feature of the assemblage from Dichin, a pattern that is repeated at most sites in the region where coins of the emperor Zeno are particularly rare. By looking at both site finds and hoards from the region, however, these explanations need to be revised as they are based on a numismatic mirage rather than archaeological fact.

Weight Minimization of a Speed Reducer Using Prey Predator Algorithm

2018 ◽  
Vol 8 (2) ◽  
pp. 19-32
Author(s):  
Surafel Luleseged Tilahun ◽  
Maba B Matadi
Keyword(s):  
Optimization Problem ◽  
Hybrid Methods ◽  
Promising Result ◽  
Mechanical Device ◽  
Exploration And Exploitation ◽  
Search Behaviour ◽  
Simulation Based ◽  
Speed Reducer ◽  
Behaviour Simulation ◽  
New Algorithms

This article describes how a speed reducer is a mechanical device which is very useful to reduce speed in different machineries. The use of gears to adjust a speed is an old practice, however the formulation of the problem as an optimization problem and solving it using different approaches begun in early 1970's. The problem is a constrained, nonlinear and nonconvex problem. That makes it challenging to handle it by deterministic approaches. Hence, different metaheuristic and hybrid methods have been proposed and used. Furthermore, due to the challenging behaviour of the problem, it has been used as a benchmark problem to test and compare new algorithms. In this article, a brief review of the problem, its application and the advances in solving the problem will be presented. A metaheuristic algorithm called prey predator algorithm will then be used to solve the problem. Prey-predator algorithm has been found to be effective with an easy way to control the exploration and exploitation search behaviour. Simulation-based comparison with previous results shows that indeed the algorithm produces a promising result. Hence, this study showed that applying prey predator algorithm for speed reducer production is a reasonable idea.

scholarly journals Insights into Exploration and Exploitation Power of Optimization Algorithm Using DSCTool

Mathematics ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1474
Author(s):  
Peter Korošec ◽  
Tome Eftimov
Keyword(s):  
Statistical Analysis ◽  
Web Service ◽  
Optimization Algorithm ◽  
Optimization Algorithms ◽  
Search Space ◽  
Exploration And Exploitation ◽  
Learning Tool ◽  
Additional Information ◽  
E Learning ◽  
Single Objective

When making statistical analysis of single-objective optimization algorithms’ performance, researchers usually estimate it according to the obtained optimization results in the form of minimal/maximal values. Though this is a good indicator about the performance of the algorithm, it does not provide any information about the reasons why it happens. One possibility to get additional information about the performance of the algorithms is to study their exploration and exploitation abilities. In this paper, we present an easy-to-use step by step pipeline that can be used for performing exploration and exploitation analysis of single-objective optimization algorithms. The pipeline is based on a web-service-based e-Learning tool called DSCTool, which can be used for making statistical analysis not only with regard to the obtained solution values but also with regard to the distribution of the solutions in the search space. Its usage does not require any special statistic knowledge from the user. The gained knowledge from such analysis can be used to better understand algorithm’s performance when compared to other algorithms or while performing hyperparameter tuning.

scholarly journals Vincent Charles Illing, 1890-1969

1970 ◽  
Vol 16 ◽  
pp. 365-384
Keyword(s):  
Oil And Gas ◽  
Scientific Work ◽  
Petroleum Exploration ◽  
Petroleum Geology ◽  
Exploration And Exploitation ◽  
Petroleum Geologist ◽  
Industrial Work ◽  
The World

Vincent Charles Illing was an internationally distinguished petroleum geologist who exemplified in his career the advantages of integrated academic and industrial work. His name will always be linked with the Royal School of Mines, London, where he created and developed over forty years the only department of petroleum geology in this country and one of the foremost in the world. His studies of the occurrence of oil and gas were no mere academic exercise. He was unique in British geology in combining the duties and responsibilities of a professor with those of guiding petroleum exploration and exploitation in various parts of the world. He never relinquished his consultant’s role. His biography is of particular interest now that pragmatism in scientific work has regained much of its former respectability.

The Microfilmed Collections of Russian Archival Materials in the Danish and Swedish National Archives

Slavic Review ◽  
1984 ◽  
Vol 43 (2) ◽  
pp. 270-275
Author(s):  
Hugh Ragsdale
Keyword(s):  
Soviet Union ◽  
National Archive ◽  
The Soviet Union ◽  
Russian State ◽  
National Archives ◽  
The World ◽  
Two Phases ◽  
State Archives ◽  
Gain Access

The national archives of Denmark and Sweden have engaged Soviet archives in extensive and probably unique exchanges of copied materials. These two archives consequently hold substantial quantities of Soviet archival records, records sometimes of extraordinary value, which in some cases are scarcely accessible in any other part of the world, including the Soviet Union. Approximately 40 percent of the holdings of Soviet documents in the Danish National Archive come from the Arkhiv vneshnei politiki Rossii. The fact that it is very difficult to gain access to this institution considerably enhances their importance. The Swedish holdings are similar.The Russian documents in both archives were acquired in two phases, and phase one was common to both. In 1928, archivists and historians from Denmark, Norway, and Sweden formed a joint Scandinavian committee for the exploration of the Russian state archives (Den Nordiske Faelleskomite for Udforskning af de russiske Statsarkiver).

SELEZIONE, STORIA DI UNA PAROLA E DI UN CONCETTO

Nuncius ◽  
2004 ◽  
pp. 143-170
Author(s):  
PIETRO OMODEO
Keyword(s):  
Evolutionary Theory ◽  
Differential Mortality ◽  
Potential Significance ◽  
Term Selection ◽  
Evolutionary Changes ◽  
The World ◽  
Environmental Variations ◽  
Two Phases ◽  
Word Selection ◽  
Alternative Solutions

Abstracttitle SUMMARY /title From the world of breeders, Darwin drew the term selection, a neologism introduced by Youatt to indicate the choice of the stallion (according to the market demands). He promptly adopted it already in the Sketch and considered its potential significance when applied to the idea that species vary through the generations. Consequently, he suggested that in nature something similar may happen in relation to the struggle for life that originates from environmental variations (and somehow parallels the variations of market demands). Darwin attempted different ways to document how this process takes place in nature, always distinguishing as two phases the struggle of life and the consequent differential mortality and fecundity that characterize the breeders of the successive generation. This conclusion, which is at the very basis of Darwin's evolutionary theory, was presented in alternative solutions to make it acceptable to the most skeptical readers. Alfred Wallace apparently solved the problem of the origin of species more directly, starting from Malthus and his conception that death chooses the weakest. He does not use the word "selection" until reading Darwin's works. However, his conception is that different rates of reproduction and death are the cause of evolutionary changes.

Sign in / Sign up

Export Citation Format

Share Document