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

Metrology for Bio Systems

The current paper addresses the advent of next generation bio system focussed Micro Nano Manufacturing Technologies (MNMT). These products and processes have placed significant new emphasis on specification and quality control systems, especially if these product and processes are to achieve economic scale up. Bio technology products and processes are a core element of MNMT and structured surfaces can be a key element in enabling bio system function. There examples of the application of such surfaces in bio systems for functions such as diverse as anti fouling and oseointegration. However a deficit exists in terms of metrology for bio structured surfaces and identifying suitable measurands and instrumentation remains a challenge for production engineers. Functional modelling would seem to point towards a better way of specifying metrology however for bio systems these are rare and often extensive function testing and clinical trials are used to inform the metrology selection. In the present paper the development of MNMT bio systems is discussed in the metrology context and several examples of developing metrology challenges. Four such bio related systems are discussed the solutions are outlined. The case studies cover traditional prosthetic implants, micro fluidic devices, cellular attachment and manufacture of cellular scaffolds

On the response surface methodology and designed experiments for computationally intensive distributed aerospace simulations

Distributed real-time simulation is the focus of intense development with complex systems being represented by individual component simulations interacting as a coherent model. Commercial off the shelf (COTS) and Freeware real-time software exists to provide data communication channels between he components subject to adequate system bandwidth. However, if the individual models are too computationally intensive to run in real-time, then the performance of the real-time simulation architecture is compromised. In this paper, model representations are developed from dynamic simulation by the Response surface Methodology, allowing complex systems to be included in a real-time environment. A Permanent Magnet AC motor drive simulation with model reference control for a more electric aircraft application is examined as a candidate for inclusion in a realtime simulation environment

Foreign Direct Investment in Manufacturing Sector in Malaysia

This paper analyses the determinants of foreign direct investment (FDI) in the manufacturing sector in Malaysia from eleven countries during the period 1988 to 2000. The empirical results indicate that gross domestic product, lending interest rate, labour productivity, exports to home country and imports from home country significantly influenced the level of FDI inflows into Malaysia. However, exchange rate, exchange rate variation, wage and openness index were not important in influencing FDI.foreign direct investment, manufacturing sector, International Relations/Trade,

Understanding the effects of decompaction maintenance on the infill state and play performance of third-generation artificial grass pitches

Third generation artificial grass pitches have been observed to get harder over time. The maintenance technique of rubber infill decompaction is intended to help slow, or reverse, this process. At present, little is understood about either the science of the infill compaction process or the efficacy of decompaction maintenance. The objective of this study was to measure the changes in rubber infill net bulk density, force reduction (impact absorption) and vertical ball rebound under various levels of compactive effort in controlled laboratory-based testing. The assessments were repeated after the systems had been raked to simulate the decompaction maintenance techniques. These tests defined the limits of compaction (loose to maximally compacted) in terms of the change in rubber infill net bulk density, force reduction and vertical ball rebound. Site testing was also undertaken at four third generation pitches immediately pre and post decompaction, to determine the measurable effects in the less well controlled field environment. Rubber infill net bulk density was found to increase as compactive effort increased, resulting in increased hardness. Decompacting the surface was found to approximately fully reverse these effects. In comparison, the site measurements demonstrated similar but notably smaller magnitudes of change following the decompaction process suggesting that the field state pre and post decompaction did not reach the extremes obtained in the laboratory. The findings suggest that rubber infill net bulk density is an important parameter influencing the hardness of artificial grass and that decompactions can be an effective method to reverse compaction related hardness changes

Artificial grass: a longitudinal study on ball roll and free pile height

Ball roll is seen as one of the first criterion which cause artificial grass pitches to fail performance standards. Previous research has demonstrated that the ball roll distance increased after a seven-year period. However, there is a lack of understanding in the mechanisms causing the ball roll distance to increase with time. During this study, the ball roll distance and free pile height were measured over a twelve-month period on an indoor pitch. The aim was to evaluate the early-life pitch performance and to determine if a correlation existed between ball roll distance and free pile height. The indoor environment protected the measurements from the confounding effects of wind and precipitation, providing a controlled environment in which to assess the effects of mechanical wear from player usage on both ball roll and free pile height. There was a general trend for the ball roll distance to increase and the free pile height to reduce with time. There was a strong, negative correlation (R= -0.967) between ball roll distance and free pile height. The ball roll distance increased above the FIFA 2* limit within the first twelve months of pitch life, however intervening drag brushing the surface was found to reduce ball roll distance to within the requirements, signifying the importance of regular drag brushing. Significant spatial variation (P<0.001) existed in ball roll and free pile height between high use and low use areas of the pitch. The study provides strong evidence on the effects of free pile height on the ball roll distance, indicating that pitch owners need effective maintenance to ensure the carpet pile remains upright to maintain ball roll distance to meet performance standards

Artificial grass: a longitudinal study on ball roll and free pile height

Ball roll is seen as one of the first criterion which cause artificial grass pitches to fail performance standards. Previous research has demonstrated that the ball roll distance increased after a seven-year period. However, there is a lack of understanding in the mechanisms causing the ball roll distance to increase with time. During this study, the ball roll distance and free pile height were measured over a twelve-month period on an indoor pitch. The aim was to evaluate the early-life pitch performance and to determine if a correlation existed between ball roll distance and free pile height. The indoor environment protected the measurements from the confounding effects of wind and precipitation, providing a controlled environment in which to assess the effects of mechanical wear from player usage on both ball roll and free pile height. There was a general trend for the ball roll distance to increase and the free pile height to reduce with time. There was a strong, negative correlation (R= -0.967) between ball roll distance and free pile height. The ball roll distance increased above the FIFA 2* limit within the first twelve months of pitch life, however intervening drag brushing the surface was found to reduce ball roll distance to within the requirements, signifying the importance of regular drag brushing. Significant spatial variation (P<0.001) existed in ball roll and free pile height between high use and low use areas of the pitch. The study provides strong evidence on the effects of free pile height on the ball roll distance, indicating that pitch owners need effective maintenance to ensure the carpet pile remains upright to maintain ball roll distance to meet performance standards