Search results for "Optimisation"

Mitigating forest biodiversity and ecosystem service losses in the era of bio-based economy

2018

Abstract Forests play a crucial role in the transition towards a bioeconomy by providing biomass to substitute for fossil-based materials and energy. However, a policy-policy conflict exists between the desire to increase the utilization of bio based renewable resources and the desire to protect and conserve biodiversity. Increasing forest harvest levels to meet the needs of the bioeconomy may conflict with biodiversity protection and ecosystem services provided by forests. Through an optimization framework, we examined trade-offs between increasing the extraction of timber resources, and the impacts on biodiversity and non-wood ecosystem services, and investigated possibilities to reconcil…

Autonomous ultrasonic inspection using Bayesian optimisation and robust outlier analysis

2020

The use of robotics is beginning to play a key role in automating the data collection process in Non Destructive Testing (NDT). Increasing the use of automation quickly leads to the gathering of large quantities of data, which makes it inefficient, perhaps even infeasible, for a human to parse the information contained in them. This paper presents a solution to this problem by making the process of NDT data acquisition an autonomous one as opposed to an automatic one. In order to achieve this, the robotic data acquisition task is treated as an optimisation problem, where one seeks to find locations with the highest indication of damage. The resulting algorithm combines damage detection tech…

Integration of gradient based and response surface methods to develop a cascade optimisation strategy for Y-shaped tube hydroforming process design

2010

International audience; In the last years a strong research effort was produced in order to develop and design new forming technologies able to overcome the typical drawbacks of traditional forming operations. Among such new technologies, hydroforming proved to be one of the most promising. The design of tube hydroforming operations is mainly aimed to prevent bursting or buckling occurrence and such issues can be pursued only if a proper control of both material feeding history and internal pressure path during the process is performed.In this paper, a proper optimisation strategy was developed on Y-shaped tube hydroforming process which is characterized by a quite complex process mechanics…

Meta-heuristic Algorithms for Nesting Problem of Rectangular Pieces

2017

Abstract Nesting problems consist of placing multiple items onto larger shapes finding a good arrangement. The goal of the nesting process is to minimize the waste of material. It is common to assume, as in the present work, that the stock sheet has fixed width and infinite height, since in the real world a company may have to cut pieces from a roll of material. The complexity of such problems is often faced with a two-stage approach, so-called “hybrid algorithm”, combining a placement routine and a meta-heuristic algorithm. Starting from a given positioning sequence, the placement routine generates a non-overlapping configuration. The encoded solution is manipulated and modified by the met…

PolyACO+: a multi-level polygon-based ant colony optimisation classifier

2017

Ant Colony Optimisation for classification has mostly been limited to rule based approaches where artificial ants walk on datasets in order to extract rules from the trends in the data, and hybrid approaches which attempt to boost the performance of existing classifiers through guided feature reductions or parameter optimisations. A recent notable example that is distinct from the mainstream approaches is PolyACO, which is a proof of concept polygon-based classifier that resorts to ant colony optimisation as a technique to create multi-edged polygons as class separators. Despite possessing some promise, PolyACO has some significant limitations, most notably, the fact of supporting classific…

A systems-wide understanding of photosynthetic acclimation in algae and higher plants

2017

The ability of phototrophs to colonise different environments relies on robust protection against oxidative stress, a critical requirement for the successful evolutionary transition from water to land. Photosynthetic organisms have developed numerous strategies to adapt their photosynthetic apparatus to changing light conditions in order to optimise their photosynthetic yield, which is crucial for life on Earth to exist. Photosynthetic acclimation is an excellent example of the complexity of biological systems, where highly diverse processes, ranging from electron excitation over protein protonation to enzymatic processes coupling ion gradients with biosynthetic activity, interact on drasti…

Shock control bump design optimization on natural laminar aerofoil

2011

The chapter investigates Shock Control Bumps (SCB) on a Natural Laminar Flow (NLF) aerofoil; RAE 5243 for Active Flow Control (AFC). A SCB approach is used to decelerate supersonic flow on the suction/pressure sides of transonic aerofoil that leads delaying shock occurrence or weakening of shock strength. Such an AFC technique reduces significantly the total drag at transonic speeds. This chapter considers the SCB shape design optimisation at two boundary layer transition positions (0 and 45%) using an Euler software coupled with viscous boundary layer effects and robust Evolutionary Algorithms (EAs). The optimisation method is based on a canonical Evolution Strategy (ES) algorithm and inco…

Evolutionary Algorithms and Metaheuristics : Applications in Engineering Design and Optimization

2018

The use of artificial intelligence techniques to optimise and control injection moulding processes

1999

In the paper a typical injection moulding process on a single-screw extrusion machine aimed to the production of axisymmetric polypropylene dishes for alimentary use has been investigated. First of all the most important process parameters have been individuated; subsequently a wide testing hyperspace has been investigated, at varying the process parameters in a large range. For each combination both some geometrical characteristics of the obtained component have been measured and the occurrence of defects has been verified. The largest part of the available data have been used to train a neural network aimed to explain the process dynamics. Furthermore an offline control system, based on f…

Optimisation of Heat Loss through Ventilation for Residential Buildings

2018

This study presents the results of research on heat loss from various types of residential buildings through ventilation systems. Experimental research was done to analyse the effectiveness of ventilation systems of different types and determine the parameters of air discharged via the ventilation ducts. A model of heat loss from the discharge of exhaust air outside through air ducts has since been developed. Experiments were conducted on three experimental systems of building ventilation: gravitational, mechanical, and supply-exhaust ventilation systems with heat recovery. The proposed model dependencies were used to chart the daily fluctuations of the optimum multiplicity of air exchange …