A method for treating dependencies between variables in a simulation risk analysis model

This thesis explores the need to recognise and represent accurately the interdependencies between uncertain quantitative components in a simulation model. Therefore, helping to fill the gap between acknowledging the importance of modelling correlation and the actual specification and implementation of a procedure for modelling accurate measures of Pearson's correlation became the main aim of this research. Two principal objectives are stated for the developed Research Correlation Model ("RCM"): (1) it is to generate Pearson-correlated paired samples of two continuous variables for which the sample correlation is a good approximation to the target correlation; and (2) the sampled values of the two individual variables must have very accurate means and variances. The research results conclude that the samples from the four chosen distributions that have been generated by the RCM have highly acceptable levels of precision when tested using x2 tests and others. The results also show that an average improvement in precision of correlation modelling was over 96 percent. Even with samples as small as 10 the worst case correction factor is only just less than 90 percent, with the average correction factor being over 96 percent overall, so that the contribution made by the RCM here is quite impressive. Overall the analysis shows that in the case when the sample size is 10, the RCM consistently generates samples whose correlation is so much more precise than that generated by @RISK. The smallest of all the observed ratios of improvements of the RCM in comparison with the use of @RISK is 2.3:1, in just one case when the medians were being compared. The average improvement ratio exceeded 100. It is concluded that the aim of specifying, formulating and developing a Pearson correlation model between a pair of continuous variables which can be incorporated into simulation models of complex applications has been achieved successfully

Expert Finding by Capturing Organisational Knowledge from Legacy Documents

Organisations capitalise on their best knowledge through the improvement of shared expertise which leads to a higher level of productivity and competency. The recognition of the need to foster the sharing of expertise has led to the development of expert finder systems that hold pointers to experts who posses specific knowledge in organisations. This paper discusses an approach to locating an expert through the application of information retrieval and analysis processes to an organization’s existing information resources, with specific reference to the engineering design domain. The approach taken was realised through an expert finder system framework. It enables the relationships of heterogeneous information sources with experts to be factored in modelling individuals’ expertise. These valuable relationships are typically ignored by existing expert finder systems, which only focus on how documents relate to their content. The developed framework also provides an architecture that can be easily adapted to different organisational environments. In addition, it also allows users to access the expertise recognition logic, giving them greater trust in the systems implemented using this framework. The framework were applied to real world application and evaluated within a major engineering company

Hole maximum density droplets of an antidot in strong magnetic fields

We investigate a quantum antidot in the integer quantum Hall regime (the filling factor is two) by using a Hartree-Fock approach and by transforming the electron antidot into a system which confines holes via an electron-hole transformation. We find that its ground state is the maximum density droplet of holes in certain parameter ranges. The competition between electron-electron interactions and the confinement potential governs the properties of the hole droplet such as its spin configuration. The ground-state transitions between the droplets with different spin configurations occur as magnetic field varies. For a bell-shape antidot containing about 300 holes, the features of the transitions are in good agreement with the predictions of a recently proposed capacitive interaction model for antidots as well as recent experimental observations. We show this agreement by obtaining the parameters of the capacitive interaction model from the Hartree-Fock results. An inverse parabolic antidot is also studied. Its ground-state transitions, however, display different magnetic-field dependence from that of a bell-shape antidot. Our study demonstrates that the shape of antidot potential affects its physical properties significantly.Comment: 12 pages, 11 figure

The ‘Face’ Barriers to Partnership

Spectrum monitoring and interference detection are crucial for the satellite service performance and the revenue of SatCom operators. Interference is one of the major causes of service degradation and deficient operational efficiency. Moreover, the satellite spectrum is becoming more crowded, as more satellites are being launched for different applications. This increases the risk of interference, which causes anomalies in the received signal, and mandates the adoption of techniques that can enable the automatic and real-time detection of such anomalies as a first step towards interference mitigation and suppression. In this paper, we present a Machine Learning (ML)-based approach able to guarantee a real-time and automatic detection of both short-term and long-term interference in the spectrum of the received signal at the base station. The proposed approach can localize the interference both in time and in frequency and is universally applicable across a discrete set of different signal spectra. We present experimental results obtained by applying our method to real spectrum data from the Swedish Space Corporation. We also compare our ML-based approach to a model-based approach applied to the same spectrum data and used as a realistic baseline. Experimental results show that our method is a more reliable interference detector.This project has received funding from the European Research Council project AGNOSTIC (742648), from the Swedish Space Corporation, and from the Swedish National Space Agency under the National Space Engineering Research Programme 3 (NRFP3).QC 20191028</p

Airport noise control through land use regulation in the vicinity of airports : the case of Kimpo International Airport

The effect of airport noise on communities surrounding airports presents a serious problem for airport operations and expansion. In order to resolve this problem, many attempts have been made to control airport noise over recent years all over the world. Of these, land use regulation is an important method for controlling' the adverse impacts of airport noise on airport environs. The success of the prevention of noise sensitive development depends on effective land use planning and control. This study reviews effective noise control through land use regulation at Kimpo International Airport, Korea. For the purpose of a more precise understanding of the noise problem, a review of the various aspects and causes of aircraft noise, the way noise is measured, its effects on people, and the methods to alleviate the adverse impact of airport noise is presented. In addition to these, the characteristics of effective land use planning around an airport, available land use control measures, and the compatible land use planning system practised in the United States, the United Kingdom and Korea are reviewed. The role of Kimpo International Airport will change to the exclusive use for domestic flights. With the opening of the new intemational airport in 2001, the noise analysis shows a significant reduction in the noise impacted area at Kimpo Airport following this change in role, due to the decrease of the number of aircraft operations and the elimination of noisier aircraft, However, the pressure for development in less impacted areas may make the airport noise problem worse in the future. In order to prevent encroaching development in the vicinity of Kimpo Airport, the following conclusions are presented: - More objective and efficient standards for land use regulation are desirable. - Compatible land use planning through the co-operative efforts of each of the various parties involved is essential for the prevention of noise sensitive development. - Developing a community relations programme is useful for the resolution of airport noise problems and the restoration of a community's confidence. - Systematic selection of noise control measures and monitoring programmes are essential for the effective management of the noise environment

The ‘Face’ Barriers to Partnership

Teaching and Learning Together in Higher Education1271-4United State