Truncated fractional moments of stable laws

Expressions are given for the truncated fractional moments $E X_+^p$ of a general stable law. These involve families of special functions that arose out of the study of multivariate stable densities and probabilities. As a particular case, an expression is given for $E(X-a)_+$ when $\alpha > 1$

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The Locus Algorithm III: A Grid Computing system to generate catalogues of optimised pointings for Differential Photometry

This paper discusses the hardware and software components of the Grid Computing system used to implement the Locus Algorithm to identify optimum pointings for differential photometry of 61,662,376 stars and 23,799 quasars. The scale of the data, together with initial operational assessments demanded a High Performance Computing (HPC) system to complete the data analysis. Grid computing was chosen as the HPC solution as the optimum choice available within this project. The physical and logical structure of the National Grid computing Infrastructure informed the approach that was taken. That approach was one of layered separation of the different project components to enable maximum flexibility and extensibility

The Locus Algorithm IV: Performance metrics of a grid computing system used to create catalogues of optimised pointings

This paper discusses the requirements for and performance metrics of the the Grid Computing system used to implement the Locus Algorithm to identify optimum pointings for differential photometry of 61,662,376 stars and 23,779 quasars. Initial operational tests indicated a need for a software system to analyse the data and a High Performance Computing system to run that software in a scalable manner. Practical assessments of the performance of the software in a serial computing environment were used to provide a benchmark against which the performance metrics of the HPC solution could be compared, as well as to indicate any bottlenecks in performance. These performance metrics indicated a distinct split in the performance dictated more by differences in the input data than by differences in the design of the systems used. This indicates a need for experimental analysis of system performance, and suggests that algorithmic complexity analyses may lead to incorrect or naive conclusions, especially in systems with high data I/O overhead such as grid computing. Further, it implies that systems which reduce or eliminate this bottleneck such as in-memory processing could lead to a substantial increase in performance

Modeling and control of an automotive fuel cell thermal system

This work develops an 8th order, non-linear thermal model of an automotive Proton Exchange Membrane (PEM) fuel cell system. Subsystem models were developed from first principals where ever possible and validated against data from a physical system. The entire model was then validated against system data from a General Motor\u27s 120kW fuel cell system. The system model was analyzed in both the time and frequency domain. Next, a reduced, 3rd order model was constructed from the full model and then linearized. The performances of all three models were compared and it was found that the 3rd order linear model provided an acceptable representation of the full non-linear model. Using the models developed in the first section, different control strategies were examined. A proportional-integral (PI) controller was developed as a baseline and compared to a full state feedback Linear Quadratic controller. This controller was augmented to include output variable feedback to improve the steady state performance of the controller. The state feedback controller was found to have faster response and less interaction between the controlled variables than the baseline controller. Because some of the states are unmeasured, an estimator was developed to determine the state values for the full state feedback controller

The Economic Crisis, Public Sector Pay, and the Income Distribution

An important aspect of the impact of the economic crisis is how pay in the public sector responds – in the face not only of the evolution of pay in the private sector, but also extreme pressure on public spending (of which pay is a very large proportion) as fiscal deficits soar. What are the effects on the income distribution of cutting public sector pay rates or alternative strategies to reduce the public sector pay bill, and how does these vary depending on the evolution of pay in the private sector? This paper investigates these issues using data and a tax-benefit simulation for Ireland, a country which faces a particularly severe fiscal crisis and where innovative measures have already been implemented to claw back pay from public sector workers in the guise of a "pensions levy", followed most recently by a significant cut in nominal pay rates. The SWITCH tax-benefit model first allows the distributional effects of these measures, which achieved a substantial reduction in the net public sector pay bill, to be teased out. The overall impact on the income distribution, set against alternative scenarios for pay in the private sector, is assessed. This provides empirical evidence relevant to policy choices in relation to a key aspect of household income over which governments have direct influence, while at the same time illustrating methodologically how a tax-benefit model can serve as the base for such investigation.public sector pay, income distribution, fiscal crisis

On the behavior of EMD and MEMD in presence of symmetric alpha-stable noise

EmpiricalMode Decomposition (EMD) and its extended versions such as Multivariate EMD (MEMD) are data-driven techniques that represent nonlinear and non-stationary data as a sum of a finite zero-mean AM-FM components referred to as Intrinsic Mode Functions (IMFs). The aim of this work is to analyze the behavior of EMD and MEMD in stochastic situations involving non-Gaussian noise, more precisely, we examine the case of Symmetric Alpha-Stable noise. We report numerical experiments supporting the claim that both EMD and MEMD act, essentially, as filter banks on each channel of the input signal in the case of Symmetric Alpha Stable noise. Reported results show that, unlike EMD, MEMD has the ability to align common frequency modes across multiple channels in same index IMFs. Further, simulations show that, contrary to EMD, for MEMD the stability property is well satisfied for the modes of lower indices and this result is exploited for the estimation of the stability index of the Symmetric Alpha Stable input signal

Identifying Alternative Revenue Streams for Independent Musicians

In the modern music industry, there has been a number of changes to the shape of the business as a whole that are affecting smaller, independent musicians in a negative way. These artists and groups are at a disadvantage because of the lack of financial resources available to them and the already limited means they have to create, distribute, and perform their music. However, after a review of a survey distributed to consumers, it is evident that there are a number of opportunities at these musician’s live performances that could be utilized to increase revenue