The Relation Between the Diameter of a Lightning Streamer and Its Radiated Radio Frequency Spectrum

Relation between diameter of lightning streamer and its radiated radio frequency spectru

The effective directivity of an isotropic antenna looking down through the ionosphere

Effective directivity of isotropic low frequency antenna looking down on earth from ionospheric meteorological satellit

Development of a whole life cycle cost model for electrification options on the UK rail system

Projects to deliver Overhead Line Equipment (OLE) electrification on the UK rail infrastructure system presents technical challenges which the rail industry in Britain have not traditionally had to consider. Whole Life Cycle assessment provides decision makers with cost estimates for the installation phase and over the entire service life of the system, including disposal. The OLE projects face a particular problem when analysing the best option for overbridges. Much of the rail infrastructure has not traditionally had to consider overhead clearances and therefore many of the bridges are only a little taller than the rolling stock. In addition to the difficulties in assessing the Life-Cycle costs of assets that have historically been used in very limited scales, the Whole Life Cycle assessment must consider the various engineering options that are available for projects. The three competing options (bridge rebuild, track lowering, reduced clearance) are all going to have very different capital expenditure (CAPEX) and operating expenditure (OPEX) costs. This work presents a model created to predict these costs over the anticipated assessment period. The developed model predicts capital expenditures, maintenance and service disruption costs and links them to the three major assets options involved in OLE underbridges

Integration of cost-risk assessment of denial of service within an intelligent maintenance system

As organisations become richer in data the function of asset management will have to increasingly use intelligent systems to control condition monitoring systems and organise maintenance. In the future the UK rail industry is anticipating having to optimize capacity by running trains closer to each other. In this situation maintenance becomes extremely problematic as within such a high-performance network a relatively minor fault will impact more trains and passengers; such denial of service causes reputational damage for the industry and causes fines to be levied against the infrastructure owner, Network Rail. Intelligent systems used to control condition monitoring systems will need to optimize for several factors; optimization for minimizing denial of service will be one such factor. With schedules anticipated to be increasingly complicated detailed estimation methods will be extremely difficult to implement. Cost prediction of maintenance activities tend to be expert driven and require extensive details, making automation of such an activity difficult. Therefore a stochastic process will be needed to approach the problem of predicting the denial of service arising from any required maintenance. Good uncertainty modelling will help to increase the confidence of estimates. This paper seeks to detail the challenges that the UK Railway industry face with regards to cost modelling of maintenance activities and outline an example of a suitable cost model for quantifying cost uncertainty. The proposed uncertainty quantification is based on historical cost data and interpretation of its statistical distributions. These estimates are then integrated in a cost model to obtain accurate uncertainty measurements of outputs through Monte-Carlo simulation methods. An additional criteria of the model was that it be suitable for integration into an existing prototype integrated intelligent maintenance system. It is anticipated that applying an integrated maintenance management system will apply significant downward pressure on maintenance budgets and reduce denial of service. Accurate cost estimation is therefore of great importance if anticipated cost efficiencies are to be achieved. While the rail industry has been the focus of this work, other industries have been considered and it is anticipated that the approach will be applicable to many other organisations across several asset management intensive industrie

An Inquiry into the Antecedents of Consumer Purchase of Non-Deceptive Counterfeit Goods: Theory, Practice and Problems

With counterfeit good consumption growing at alarming rates each year, this topic is increasingly demanding attention of marketing academics. This dissertation examines two sets of factors that influence consumer attitude toward counterfeits: sociocultural influences and psychological influences. Based on a review of the literature, two constructs, namely information susceptibility and normative susceptibility are combined to form a group of sociocultural influences expected to influence consumer attitude toward counterfeits. In addition, five constructs are combined to represent psychological influences, namely value consciousness, self-identity, integrity, materialism and perceived risk. Data was collected through a web-based survey and features a cross-sectional design. Utilizing a sample of 228 respondents, confirmatory factor analysis coupled with structural equation modeling was employed to analyze hypothesized relationships. Results suggest the most significant influence on consumer attitude toward counterfeits is integrity the more integrity held by a consumer, the less favorable their attitude toward counterfeits. In addition, materialism and normative susceptibility were also found to be positively related to consumer attitude toward counterfeits. Consumer attitude toward counterfeits was also shown to have positive significance as a mediating variable between the antecedents and purchase intention. The results of this dissertation suggest that consumers, and their reference groups justify purchasing counterfeit items due to what they believe to be unfair business practices such as charging too much. This research will assist scholars, marketers, and government agencies to understand the implications of counterfeit good consumption and contribute to the development of effective strategies to counter the purchase of non-deceptive counterfeit good

Multiple Components in Narrow Planetary Rings

The phase-space volume of regions of regular or trapped motion, for bounded or scattering systems with two degrees of freedom respectively, displays universal properties. In particular, drastic reductions in the volume (gaps) are observed at specific values of a control parameter. Using the stability resonances we show that they, and not the mean-motion resonances, account for the position of these gaps. For more degrees of freedom, exciting these resonances divides the regions of trapped motion. For planetary rings, we demonstrate that this mechanism yields rings with multiple components.Comment: 4 pages, 7 figures (some in colors

Decision Analysis with Geographically Varying Outcomes: Preference Models and Illustrative Applications

DRMI Working Paper SeriesThe series is intended to convey the preliminary results of [DRMI] ongoing research. The research described in these papers is preliminary and has not completed the usual review process for Institute publications. We welcome feedback from readers and encourage you to convey your comments and criticisms directly to the authors