MULTIPLE HELICAL PERVERSIONS OF FINITE, INTRISTICALLY CURVED RODS

We investigate mechanical spatial equilibria of slender elastic rods with intristic curvature. Our work is, to some extent, motivated by papers [Goriely & Tabor, 1998; Goriely & McMillen 2002]. There such rods of infinite length were recently studied to quantify the behavior of botanical filaments. In particular, an adequate explanation for the existence of helical perversions (the transition between helical segments of opposite handedness) is provided in [Goriely & Tabor, 1998]. However, this theory fails to describe multiple perversions, which can be observed in Nature. In contrast we formulate a two-point boundary-value problem describing rods of finite length with initial curvature and clamped ends. We identify trivial solutions as straight configurations and also k-covered circles, rigorously establish the existence of local bifurcations, and then compute global solutions via the Parallel Hybrid Algorithm [Domokos & Szeberényi, 2004] to find spatially complex equilibria characterized by multiple perversions. Based on computational results and the White–Fuller theorem [White, 1969; Fuller, 1971; Calugareanu, 1961] we describe a heuristic global picture of the bifurcation diagram, which can serve as an explanation for the evolution of physically observable tendril shapes.

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GLOBAL SOLUTIONS OF THE EQUATION OF THE KIRCHHOFF ELASTIC ROD IN SPACE FORMS

Bulletin of the Australian Mathematical Society ◽

10.1017/s0004972712000767 ◽

2012 ◽

Vol 88 (1) ◽

pp. 70-80 ◽

Cited By ~ 2

Author(s):

SATOSHI KAWAKUBO

Keyword(s):

Space Form ◽

Global Solutions ◽

Infinite Length ◽

Elastic Rods ◽

Elastic Rod ◽

Lagrange Equations ◽

Initial Value ◽

Space Forms ◽

Equilibrium Configurations ◽

Rod Of Finite Length

AbstractThe Kirchhoff elastic rod is one of the mathematical models of equilibrium configurations of thin elastic rods, and is defined to be a solution of the Euler–Lagrange equations associated to the energy with the effect of bending and twisting. In this paper, we consider Kirchhoff elastic rods in a space form. In particular, we give the existence and uniqueness of global solutions of the initial-value problem for the Euler–Lagrange equations. This implies that an arbitrary Kirchhoff elastic rod of finite length extends to that of infinite length.

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PARALLEL HYBRID METAHEURISTIC ON SHARED MEMORY SYSTEM FOR REAL-TIME UAV PATH PLANNING

International Journal of Computational Intelligence and Applications ◽

10.1142/s1469026814500084 ◽

2014 ◽

Vol 13 (02) ◽

pp. 1450008 ◽

Cited By ~ 7

Author(s):

VINCENT ROBERGE ◽

MOHAMMED TARBOUCHI ◽

FRANÇOIS ALLAIRE

Keyword(s):

Real Time ◽

Shared Memory ◽

Execution Time ◽

Hybrid Algorithm ◽

Statistical Significance ◽

Optimization Methods ◽

Memory System ◽

Hybrid Metaheuristic ◽

Parallel Hybrid ◽

Shared Memory System

In this paper, we present a parallel hybrid metaheuristic that combines the strengths of the particle swarm optimization (PSO) and the genetic algorithm (GA) to produce an improved path-planner algorithm for fixed wing unmanned aerial vehicles (UAVs). The proposed solution uses a multi-objective cost function we developed and generates in real-time feasible and quasi-optimal trajectories in complex 3D environments. Our parallel hybrid algorithm simulates multiple GA populations and PSO swarms in parallel while allowing migration of solutions. This collaboration between the GA and the PSO leads to an algorithm that exhibits the strengths of both optimization methods and produces superior solutions. Moreover, by using the "single-program, multiple-data" parallel programming paradigm, we maximize the use of today's multicore CPU and significantly reduce the execution time of the parallel program compared to a sequential implementation. We observed a quasi-linear speedup of 10.7 times faster on a 12-core shared memory system resulting in an execution time of 5 s which allows in-flight planning. Finally, we show with statistical significance that our parallel hybrid algorithm produces superior trajectories to the parallel GA or the parallel PSO we previously developed.

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Portfolio Optimization based on Synthetic Fish Congestion Algorithm and Artificial Intelligence: In the Condition of Uncertainty and Half-Variance Risk

Journal of Advanced Research in Dynamical and Control Systems ◽

10.5373/jardcs/v12i10/20202651 ◽

2020 ◽

Vol 12 (10) ◽

pp. 01-12

Author(s):

Reza Abedi Ghahderijani ◽

Sayed Mojtaba Mirlohi ◽

Fariborzj olai ◽

Abdolmajid Abdolbaghi Ataabadi

Keyword(s):

Artificial Intelligence ◽

Portfolio Optimization ◽

Hybrid Algorithm ◽

Combination Method ◽

Optimal Selection ◽

Computational Results ◽

Artificial Immunity ◽

Variance Risk ◽

Stock Portfolio ◽

Selection Of

The issue of stock portfolio optimization is the most well-known issue in the area of optimization. The purpose of this issue is to create a portfolio among different stocks in such a way that it has the highest returns and the least risk. The problem of optimal selection of stock portfolio is one of the Non-deterministic polynomial hardproblems (NP-hard). For this reason, this article introduces a new hybrid algorithm based on artificial immunity algorithm and swarm of fish algorithm. The computational results show that the proposed combination method has the ability to find the best investment boundary in comparison to other proposed methods.

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