On-line multiobjective automatic control system generation by evolutionary algorithms

Evolutionary algorithms are applied to the on- line generation of servo-motor control systems. In this paper, the evolving population of controllers is evaluated at run-time via hardware in the loop, rather than on a simulated model. Disturbances are also introduced at run-time in order to pro- duce robust performance. Multiobjective optimisation of both PI and Fuzzy Logic controllers is considered. Finally an on-line implementation of Genetic Programming is presented based around the Simulink standard blockset. The on-line designed controllers are shown to be robust to both system noise and ex- ternal disturbances while still demonstrating excellent steady- state and dvnamic characteristics

Microstructure of interpass rolled wire + arc additive manufacturing Ti-6Al-4V components

Mechanical property anisotropy is one of the issues that are limiting the industrial adoption of additive manufacturing (AM) Ti-6Al-4V components. To improve the deposits’ microstructure, the effect of high-pressure interpass rolling was evaluated, and a flat and a profiled roller were compared. The microstructure was changed from large columnar prior beta grains that traversed the component to equiaxed grains that were between 56 and 139 μm in size. The repetitive variation in Widmanstätten alpha lamellae size was retained; however, with rolling, the overall size was reduced. A “fundamental study” was used to gain insight into the microstructural changes that occurred due to the combination of deformation and deposition. High-pressure interpass rolling can overcome many of the shortcomings of AM, potentially aiding industrial implementation of the process.EPSRC, AirBu

Investigation of low current gas tungsten arc welding using split anode calorimetry

Most previous split anode calorimetry research has applied high weld currents which exhibit pseudo Gaussian distributions of arc current and power density. In this paper we investigate low current arcs and show that both the current and power distributions have minima in the centre – varying significantly from the expected Gaussian profile. This was postulated due to the formation of the arc with the copper anode and the tungsten cathode. Furthermore, a number of parameters were varied including the step size between measurements, anode thickness and anode surface condition as well as cathode type and tip geometry. The step size between measurements significantly influenced the distribution profile and the anode thickness needed to be above 7 mm to obtain consistent results

Metamodelling of multivariable engine models for real-time flight simulation.

Sophisticated real-time distributed flight simulation environments may be constructed from a wide range of modelling and simulation tools. In this way accuracy, detail and model flexibility may be incorporated into the simulator. Distributed components may be constructed by a wide range of methods, from high level environments such as Matlab, through coded environments such as C or Fortran to hardware-in-the- loop. In this paper the Response Surface Methodology is combined with a hyper-heuristic (evolutionary algorithm) and applied to the representation of computationally intensive non-linear multivariable engine modelling. The paper investigates the potential for metamodelling (models of models) dynamic models which were previously too slow to be included in multi-component, high resolution real-time simulation environments. A multi-dimensional gas turbine model with five primary control inputs, six environmental inputs and eleven outputs is considered. An investigation has been conducted to ascertain to what extent these systems can be approximated by response surfaces with experiments which have been designed by hyper-heuristics as a first step towards automatic modelling methodology

Too sick to drive : how motion sickness severity impacts human performance

There are multiple concerns surrounding the development and rollout of self-driving cars. One issue has largely gone unnoticed - the adverse effects of motion sickness as induced by self-driving cars. The literature suggests conditionally, highly and fully autonomous vehicles will increase the onset likelihood and severity of motion sickness. Previous research has shown motion sickness can have a significant negative impact on human performance. This paper uses a simulator study design with 51 participants to assess if the scale of motion sickness is a predictor of human performance degradation. This paper finds little proof that subjective motion sickness severity is an effective indicator of the scale of human performance degradation. The performance change of participants with lower subjective motion sickness is mostly statistically indistinguishable from those with higher subjective sickness. Conclusively, those with even acute motion sickness may be just as affected as those with higher sickness, considering human performance. Building on these results, it could indicate motion sickness should be a consideration for understanding user ability to regain control of a self-driving vehicle, even if not feeling subjectively unwell. Effectiveness of subjective scoring is discussed and future research is proposed to help ensure the successful rollout of self-driving vehicles

Observations on Flights of Released Tobacco Hornworm Moths, Manduca Sexta (Johannson) Order Lepidoptera: Family Sphingidae

Author Institution: 203 Mooreland Drive, Oxford, North Carolina 27565STEWART, PAUL A. Observations on Flights of Released Tobacco Hornworm Moths, Manduca- sexla (johannson) Order Lepidoptera; Family Sphingi'dae. Ohio J. Sci. 75(2): 83, 1975

Contemporary training practices in elite british powerlifters:survey results from an international competition

The primary objective of this study was to investigate current powerlifting training methods in light of anecdotal evidence purporting increased similarity with the explosive training practices of weightlifters. The study also assessed the prevalence of contemporary training practices frequently recommended for powerlifters in the popular literature. A 20-item survey was distributed to 32 elite British powerlifters at an International competition. The subject group included multiple national, international, and commonwealth champions and record holders. Based on 2007 competition results, the average Wilks score of the group was 450.26 ± 34.7. The response rate for the surveys was 88% (28 of 32). The survey was sectioned into 6 areas of inquiry: a) repetition speed, b) explosive training load, c) resistance materials used, d) adjunct power training methods, e) exercise selection, and f) training organization. The results demonstrate that the majority of powerlifters train with the intention to explosively lift maximal and submaximal loads (79 and 82%, respectively). Results revealed that 39% of the lifters regularly used elastic bands and that 57% incorporated chains in their training. Evidence for convergence of training practices between powerlifters and weightlifters was found when 69% of the subjects reported using the Olympic lifts or their derivatives as part of their powerlifting training. Collectively, the results demonstrate that previous notions of how powerlifters train are outdated. Contemporary powerlifters incorporate a variety of training practices that are focused on developing both explosive and maximal strength

A smart driving smartphone application : real-world effects on driving performance and glance behaviours

A smart driving Smartphone application – which offers real-time fuel efficiency and safety feedback to the driver in the vehicle – was evaluated in a real-world driving study. Forty participants drove an instrumented vehicle over a 50 minute mixed route driving scenario, with 15 being selected for video data analysis. Two conditions were adopted, one a control, the other with smart driving advice being presented to the driver. Key findings from the study showed a 4.1% improvement in fuel efficiency when using the smart driving system, and an almost 3-fold reduction in time spent travelling closer than 1.5 seconds to the vehicle in front. Glance behavior results showed that drivers spent an average of 4.3% of their time looking at the system, at an average of 0.43 seconds per glance, with no glances of greater than two seconds. In conclusion this study has shown that a smart driving system specifically developed and designed with the drivers’ information requirements in mind can lead to significant improvements in real-world driving behaviours, whilst limiting visual distraction, with the task being integrated into normal driving

The Porter Hypothesis at 20: can Environmental Regulation Enhance Innovation and Competitiveness?

Twenty years ago, Harvard Business School economist and strategy professor Michael Porter stood conventional wisdom about the impact of environmental regulation on business on its head by declaring that well designed regulation could actually enhance competitiveness. The traditional view of environmental regulation held by virtually all economists until that time was that requiring firms to reduce an externality like pollution necessarily restricted their options and thus by definition reduced their profits. After all, if there are profitable opportunities to reduce pollution, profit maximizing firms would already be taking advantage of those opportunities. Over the past 20 years, much has been written about what has since become known simply as the Porter Hypothesis (“PH”). Yet, even today, there is conflicting evidence, alternative theories that might explain the PH, and oftentimes a misunderstanding of what the PH does and does not say. This paper provides an overview of the key theoretical and empirical insights on the PH to date, draw policy implications from these insights, and sketches out major research themes going forward.Porter Hypothesis, environmental policy, innovation, performance.