Method fragments

The traditional unit of analysis in knowledge acquisition and requirements acquisition is the method, e.g. the interview, the repertory grid etc. There are practical and theoretical difficulties with this division. A more useful concept is the method fragment, described in this paper. The method fragment is a discrete component of a method which can be used in one or more methods. The discreteness of method fragments makes it much easier to describe their strengths and weaknesses than is the case with methods, enabling the elicitor to put together a customized method to suit a particular elicitation need. In this paper we outline the concept of method fragments using worked examples, discuss issues raised and make recommendations for further work.     

Three-dimensional dynamic response modeling of floating nuclear plants using finite element methods

A modelling technique which can be used to obtain the dynamic response of a floating nuclear plant (FNP) moored in an artificial basin is presented. Hydrodynamic effects of the seawater in the basin have a significant impact on the response of the FNP and must be included. A three-dimensional model of the platform and mooring system (using beam elements) is used, with the hydrodynamic effects represented by added mass and damping. For an essentially square plant in close proximity to the site structures, the three-dimensional nature of the basin must be considered in evaluating the added mass and damping. However, direct solutions for hydrodynamic effects with complex basin geometry are not, as yet, available. A method for estimating these effects from planar finite element analysis is developed.First, added mass and damping values are obtained from plane-strain finite element models of vertical cross sections through the platform. Fluid finite elements are used to model the seawater. For added mass calculations, the planar models include the platform cross section, the basin profile and the seawater in the basin. For hydrodynamic damping calculations, the planar model includes the platform cross section, the seabed and seawater, infinite in horizontal extent. Added mass and damping values are obtained for each significant mode of platform response. Estimates of three-dimensional added mass and damping are then obtained through combinations of the planar values. The release of the planar contraints of seawater motion and the reflection of gravity waves back to the platform are considered. Effective damping values applicable, on an average, for the entire response time are calculated for each plant mode of response. Since added mass and damping are frequency dependent, the selection of values to be used for a specific loading condition is usually an iterative process.The accuracy of the planar finite element model in obtaining two-dimensional added mass and damping is shown through comparison with existing and documented results. In addition, a comparison is shown for open ocean added mass and damping with a three-dimensional solution using velocity potential functions. It is concluded that the overall technique results in a reasonable and conservative calculation of the dynamic response of the floating nuclear plant.     

Susceptibility to faking of the Defining Issues Test of moral development.

Administered the Defining Issues Test (DIT) by J. Rest et al to 146 student teachers on 2 occasions with instructions to either fake bad, fake good, or record their own views (standard instructions). Results support the general theory of a sequence of cognitive stages of moral judgment in which Ss recognize stages they have passed through as immature and can respond appropriately when asked to fake low, while stages higher than the S's own are unattainable thus preventing faking upwards. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rating non-technical skills: developing a behavioural marker system for use in anaesthesia

Studies of performance in medicine are often based on observation. Videotape provides a valuable tool for recording events from both real environments and simulators. When analysing observational data it is important that robust tools are used, particularly when investigating non-technical (cognitive and social) skills. This paper describes the method used to identify the key non-technical skills required in anaesthesia and to develop a behavioural marker system for their measurement. A prototype taxonomy was designed on the basis of a literature review; an examination of existing marker systems; cognitive task analysis interviews; an iterative development process involving workshops; and cross-checking in theatre. The resulting anaesthetists non-technical skills (ANTS) system comprises four skill categories (task management, team working, situation awareness, and decision making) that divide into 15 elements, each with example behaviours. Preliminary evaluation using ratings of videotaped scenarios indicated that the skills were observable and could be rated with reasonable agreement.Georgina Fletcher is now with the National Patient Safety Agency, London.     

The sorting techniques: a tutorial paper on card sorts, picture sorts and item sorts

Abstract: Although sorting techniques (e.g. card sorts) are widely used in knowledge acquisition and requirements acquisition, they have received little formal attention compared to related techniques such as repertory grids and laddering. This paper briefly describes the main sorting techniques, and then provides a detailed tutorial on one variety (repeated single‐criterion sorts), using a worked example. Guidelines for choice and sequencing of techniques are given, both in relation to varieties of sorting technique and in relation to other techniques. It is concluded that the sorting techniques are a valuable part of the elicitor's methodological toolkit.     

Refined cracked concrete analysis of concrete containment structures subject to operational and environmental loadings

Recent commercial nuclear power plant containment concepts involve the use of large reinforced concrete structures to form pressure boundaries. Where these structures are not provided with an integral steel liner, excessive cracking of the concrete under loads could result in the loss of the pressure boundary integrity with the risk of over-pressurization of other structures. Cracking of concrete is a local phenomenon and considerable detail must be included in any analytical model to obtain sufficiently refined results for the prediction of crack size and propagation. This imposes severe limitations on the overall size of structures or structural components for which detailed cracking analysis can be considered directly. To overcome this restriction, a two step procedure was developed in which linear analyses were performed to obtain the gross response, and nonlinear cracking analyses were performed for selected portions of the structure to evaluate local cracking in detail. Through iteration, compatibility of behavior between the linear and nonlinear analyses was achieved with the gross response being used to extrapolate the local cracking results to predict cracking over the entire structure. This paper discusses the analysis procedures for the detailed evaluation of cracking in large reinforced concrete structures and components. Analyses performed for an actual unlined reinforced concrete containment structure using these procedures are discussed and results are presented.     

The uses of 'contrived' knowledge elicitation techniques

Abstract: Despite a reappraisal of the view that knowledge acquisition (KA) forms a major bottleneck in the development of knowledge-based systems, there is still room for considerable improvement both in the efficiency of the development process and the quality of the final product. A set of techniques which is at present under-used in KA is the group of so-called 'contrived' techniques, namely repertory grids, sorting and laddering. These techniques have proved useful in their areas of origin, where they have been used to elicit knowledge that is not readily apparent using more traditional techniques, such as self reports and interviews. The advantages both of the individual contrived knowledge elicitation techniques and of the synergies between them ensure that they can make a substantial contribution to knowledge engineering practice.