Ride quality judgements as a function of environmental, personality, and ride spectra correlates

Personality and demographic correlates, as well as physical correlates, of ride-quality judgements in a field situation namely, in selected passenger-train ride segments, were identified and investigated

Real time resource scheduling within a distributed collaborative design environment

Operational design co-ordination is provided by a Virtual Integration Platform (VIP) that is capable of scheduling and allocating design activities to organisationally and geographically distributed designers. To achieve this, the platform consists of a number of components that contribute to the engineering management and co-ordination of data, resources, activities, requirements and processes. The information required to schedule and allocate activities to designers is defined in terms of: the designers' capability to perform particular design activities; commitment in terms of the design activities that it is currently performing, and capacity to perform more than one design activity at the same time as well as the effect of increased capacity on capability. Previous approaches have been developed by the authors to automatically allocate resources to activities [1-3], however these approaches have generally been applied either within the context of real-time allocation of computational resources using automated design tools, or in the planning of human resources within future design projects and not for the real-time allocation of activities to a combination of human and computational resources. The procedure presented here is based upon this previous research and involves: the determination of the design activities that need to be undertaken on the basis of the goals that need to be achieved; identification of the resources that can undertake these design activities; and, the use of a genetic algorithm to optimally allocate the activities to the resources. Since the focus of the procedure is toward the real-time allocation of design activities to designers, additional human issues with respect to scheduling are considered. These human issues aspects include: consideration of the improvement in performance as a result of the experience gained from undertaking the activity; provision of a training period to allow inexperienced designers the opportunity to improve their performance without their performance being assessed; and the course of action to take when a designer is either unwilling or unable to perform an activity

Study of low acceleration space transportation systems. Volume I - Summary Phase II STUDY report

Technical feasibility of electric-nuclear propulsion system for manned Mars missio

Real-time co-ordinated resource management in a computational enviroment

Design co-ordination is an emerging engineering design management philosophy with its emphasis on timeliness and appropriateness. Furthermore, a key element of design coordination has been identified as resource management, the aim of which is to facilitate the optimised use of resources throughout a dynamic and changeable process. An approach to operational design co-ordination has been developed, which incorporates the appropriate techniques to ensure that the aim of co-ordinated resource management can be fulfilled. This approach has been realised within an agent-based software system, called the Design Coordination System (DCS), such that a computational design analysis can be managed in a coherent and co-ordinated manner. The DCS is applied to a computational analysis for turbine blade design provided by industry. The application of the DCS involves resources, i.e. workstations within a computer network, being utilised to perform the computational analysis involving the use of a suite of software tools to calculate stress and vibration characteristics of turbine blades. Furthermore, the application of the system shows that the utilisation of resources can be optimised throughout the computational design analysis despite the variable nature of the computer network

A review and preliminary evaluation of methodological factors in performance assessments of time-varying aircraft noise effects

The effects of aircraft noise on human performance is considered. Progress is reported in the following areas: (1) review of the literature to identify the methodological and stimulus parameters involved in the study of noise effects on human performance; (2) development of a theoretical framework to provide working hypotheses as to the effects of noise on complex human performance; and (3) data collection on the first of several experimental investigations designed to provide tests of the hypotheses

A generic coordination approach applied to a manufacturing environment

This paper describes a generic coordination approach applied to the field of manufacturing engineering. The objective of the coordination mechanism with respect to this application is twofold. Firstly, it is shown that utilising the developed system can result in the efficient organisation of processes leading to a near optimum time taken to manufacture a number of artefacts. Secondly, successful operation of the system in this environment will demonstrate that the approach is generic in nature. The results already achieved using this system within a computational analysis environment supports this hypothesis

Interactive boundary element analysis for engineering design.

Structural design of mechanical components is an iterative process that involves multiple stress analysis runs; this can be time consuming and expensive. Significant improvements in the eciency of this process can be made by increasing the level of interactivity. One approach is through real-time re-analysis of models with continuously updating geometry. Three primary areas need to be considered to accelerate the re-solution of boundary element problems. These are re-meshing the model, updating the boundary element system of equations and re-solution of the system. Once the initial model has been constructed and solved, the user may apply geometric perturbations to parts of the model. The re-meshing algorithm must accommodate these changes in geometry whilst retaining as much of the existing mesh as possible. This allows the majority of the previous boundary element system of equations to be re-used for the new analysis. For this problem, a GMRES solver has been shown to provide the fastest convergence rate. Further time savings can be made by preconditioning the updated system with the LU decomposition of the original system. Using these techniques, near real-time analysis can be achieved for 3D simulations; for 2D models such real-time performance has already been demonstrated

A methodology for design coordination in a distributed computing environment

At the conceptual stage of the design process it is increasingly common that analysis tools are involved in the evaluation of a large number of alternative designs. Designers use such analysis tools to assist with large scale concept evaluations and the prediction of good initial designs. Consequently there exists a need to coordinate these analysis tools to enable the early stage of design to be performed in a timely and efficient manner. This paper describes a generic methodology that allows the management and coordination of design analysis tools. A Computer Aided Design tool, namely the Design Coordination System (DCS), has been developed to assist the designer in performing computational analysis in a distributed computing environment. Within the DCS, a collection of design agents act as members of a multi-functional team operating in a cooperative and coordinated manner in order to satisfy the objective of efficiently performing the design analysis

Extended isogeometric boundary element method (XIBEM) for two-dimensional Helmholtz problems.

Isogeometric analysis is a topic of considerable interest in the field of numerical analysis. The boundary element method (BEM) requires only the bounding surface of geometries to be described; this makes non-uniform rational B-splines (NURBS), which commonly describe the bounding curve or surface of geometries in CAD software, appear to be a natural tool for the approach. This isogeometric analysis BEM (IGABEM) provides accuracy benefits over conventional BEM schemes due to the analytical geometry provided by NURBS. When applied to wave problems, it has been shown that enriching BEM approximations with a partition-of-unity basis, in what has become known as the PU-BEM, allows highly accurate solutions to be obtained with a much reduced number of degrees of freedom. This paper combines these approaches and presents an extended isogeometric BEM (XIBEM) which uses partition-of-unity enriched NURBS functions; this new approach provides benefits which surpass those of both the IGABEM and the PU-BEM. Two numerical examples are given: a single scattering cylinder and a multiple-scatterer made up of two capsules and a cylinder