Unionism and peer-referencing

This study assesses the “fair-wage-effort” hypothesis, by examining (a) the relationship between relative wage comparisons and job satisfaction and quitting intensions, and (b) the relative ranking of stated effort inducing-incentives, in a novel dataset of unionised and non-unionised European employees. By distinguishing between downward and upward-looking wage comparisons, it is shown that wage comparisons to similar workers exert an asymmetric impact on the job satisfaction of union workers, a pattern consistent with inequity-aversion and conformism to the reference point. Moreover, union workers evaluate peer observation and good industrial relations more highly than payment and other incentives. In contrast, non-union workers are found to be more status-seeking in their satisfaction responses and less dependent on their peers in their effort choices The results are robust to endogenous union membership, considerations of generic loss aversion and across different tenure profiles. They are supportive of the individual egalitarian bias of collective wage determination and self-enforcing effort norms.EPICURUS, a project supported by the European Commission through the 5th Framework Programme “Improving Human Potential” (contract number: HPSE-CT-2002-00143

Correlation, price discovery and co-movement of ABS and equity

Asset-backed securitization (ABS) has become a viable and increasingly attractive risk management and refinancing method either as a standalone form of structured finance or as securitized debt in Collateralized Debt Obligations (CDO). However, the absence of industry standardization has prevented rising investment demand from translating into market liquidity comparable to traditional fixed income instruments, in all but a few selected market segments. Particularly low financial transparency and complex security designs inhibits profound analysis of secondary market pricing and how it relates to established forms of external finance. This paper represents the first attempt to measure the intertemporal, bivariate causal relationship between matched price series of equity and ABS issued by the same entity. In a two-dimensional linear system of simultaneous equations we investigate the short-term dynamics and long-term consistency of daily secondary market data from the U.K. Sterling ABS/MBS market and exchange traded shares between 1998 and 2004 with and without the presence of cointegration. Our causality framework delivers compelling empirical support for a strong co-movement between matched price series of ABS-equity pairs, where ABS markets seem to contribute more to price discovery over the long run. Controlling for cointegration, risk-free interest and average market risk of corporate debt hardly alters our results. However, once we qualify the magnitude and direction of price discovery on various security characteristics, such as the ABS asset class, we find that ABS-equity pairs with large-scale CMBS/RMBS and credit card/student loan ABS reveal stronger lead-lag relationships and joint price dynamics than whole business ABS. JEL Classifications: G10, G12, G2

Reconstructing cosmic growth with kSZ observations in the era of Stage IV experiments

Future ground-based CMB experiments will generate competitive large-scale structure datasets by precisely characterizing CMB secondary anisotropies over a large fraction of the sky. We describe a method for constraining the growth rate of structure to sub-1% precision out to $z\approx 1$, using a combination of galaxy cluster peculiar velocities measured using the kinetic Sunyaev-Zel'dovich (kSZ) effect, and the velocity field reconstructed from galaxy redshift surveys. We consider only thermal SZ-selected cluster samples, which will consist of $\mathcal{O}(10^4-10^5)$ sources for Stage 3 and 4 CMB experiments respectively. Three different methods for separating the kSZ effect from the primary CMB are compared, including a novel blind "constrained realization" method that improves signal-to-noise by a factor of $\sim 2$ over a commonly-used aperture photometry technique. Measurements of the integrated tSZ $y$-parameter are used to break the kSZ velocity-optical depth degeneracy, and the effects of including CMB polarization and SZ profile uncertainties are also considered. A combination of future Stage 4 experiments should be able to measure the product of the growth and expansion rates, $\alpha\equiv f H$, to better than 1% in bins of $\Delta z = 0.1$ out to $z \approx 1$ -- competitive with contemporary redshift-space distortion constraints from galaxy surveys.Comment: 16 pages, 8 figure

Estimating the bias of a noisy coin

Optimal estimation of a coin's bias using noisy data is surprisingly different from the same problem with noiseless data. We study this problem using entropy risk to quantify estimators' accuracy. We generalize the "add Beta" estimators that work well for noiseless coins, and we find that these hedged maximum-likelihood (HML) estimators achieve a worst-case risk of O(N^{-1/2}) on noisy coins, in contrast to O(1/N) in the noiseless case. We demonstrate that this increased risk is unavoidable and intrinsic to noisy coins, by constructing minimax estimators (numerically). However, minimax estimators introduce extreme bias in return for slight improvements in the worst-case risk. So we introduce a pointwise lower bound on the minimum achievable risk as an alternative to the minimax criterion, and use this bound to show that HML estimators are pretty good. We conclude with a survey of scientific applications of the noisy coin model in social science, physical science, and quantum information science.Comment: 10 page

A Novel Approach To Measure Product Quality In Sustainable Supplier Selection

A gap remains due to the intangible and qualitative criteria used to measure product quality for supplier evaluation and selection. Improving product quality is a crucial strategy for achieving reduce, reuse, recycle, and recovery. Quality characteristics are described as functional relationships (called profiles), and with the advancements in measurement technology, high dimensional data are collected. Nonetheless, prior studies have not addressed sustainable supplier selection where a nonlinear profile characterizes the product quality. Hence, this study aims to provide a novel approach to measure product quality using the process yield index, presents multiple comparisons with the best and difference test statistics and proposes a Bonferroni correction method. This study applies a Monte Carlo simulation to find the selection power and the required number of profiles. The statistical properties are investigated, and a comparison study is performed. The results show that multiple comparisons with the best outperform the Bonferroni method regarding the sample size requirement and power, and the number of levels and profiles were found to impact the power of the statistical tests. The required number of profiles and the critical value are tabulated for decision-makers

Reflective Coating for Lightweight X-Ray Optics

X-ray reflective coating for next generation's lightweight, high resolution, optics for astronomy requires thin-film deposition that is precisely fine-tuned so that it will not distort the thin sub-mm substrates. Film of very low stress is required. Alternatively, mirror distortion can be cancelled by precisely balancing the deformation from multiple films. We will present results on metallic film deposition for the lightweight optics under development. These efforts include: low-stress deposition by magnetron sputtering and atomic layer deposition of the metals, balancing of gross deformation with two-layer depositions of opposite stresses and with depositions on both sides of the thin mirrors

Thermal Modelling of the Ventilation and Cooling inside Axial Flux Permanent Magnet Generators

Axial flux permanent magnet generators are of particular interest for power generation in harsh and confined conditions. Due to their compactness and high power density, the ventilation and cooling inside axial flux permanent magnet generators have becoming increasingly important for further performance improvement. This thesis describes the developments of a lumped parameter, thermal modelling technique for axial flux permanent magnet generators. The main aim of this research is to develop a fast and accurate thermal modelling tool which can be used for rapid machine design and ultimately, to replace complex and time consuming CFD analyses in the machine design process. The thesis illustrates the construction of a generic thermal equivalent circuit, which comprises of conductive and convective sub-circuits, to model the conduction and convection heat transfers and temperature distributions in the radial and axial directions, within these machines. The conduction heat transfer between the solid components of these electrical machines is modelled by an annulus conductive thermal circuit derived from previous researchers; whereas, for convection heat transfer between the working fluid (air) and solids, the author has developed two convective thermal circuits, which are demonstrated as the Temperature Passing Method (TPM) and Heat Pick-up method in (HPM) in the thesis. Several case studies were designed to investigate the validity and accuracy of these thermal sub-circuits with both steady and transient boundary conditions. Since all the thermal impedances and capacitances used in the thermal circuits are in dimensionless form, the developed generic thermal equivalent circuit is capable of performing thermal simulations for axial flux generators of different sizes and topologies. Furthermore, special correction factors were introduced into the developed generic thermal equivalent circuit, to take into account the heat transfer in the circumferential direction in axial flux machines. The thesis also demonstrates how the heat transfer in the stator windings is modelled in the generic thermal equivalent circuit. Two analytical models, which are the Simple Concentric Model (SCM) and Concentric-annulus Layer Model (CLM) were developed, for the evaluation of the thermal resistances of the stator windings. The results evaluated from these analytical models were validated by several numerical models and experimental results of two-phase materials published by previous researchers. Lastly, experimental validation of the lumped parameter thermal equivalent circuit model and CFD simulations was conducted. Heat transfer coefficient measurements were carried out on two separate test rigs, which were a simplified single-sided axial flux machine test rig and a large-scale low speed axial flux machine. The experimental results were compared with the numerical results obtained from both the lumped parameter and CFD models. Good agreement between the experimental, lumped parameter model and CFD results were found. These indicate that the developed generic thermal circuit is potentially capable of replacing CFD analyses in the axial flux machines design process

Optimum design and machining parameters of a permanent magnet brushless DC linear motor as a CNC feed drive

A new heuristic has been developed to determine optimal operating parameters applied to a permanent magnet brushless DC linear motor (PMBDCLM) as a CNC feed drive. An FEA model has been developed utilizing an -electromagnetic postprocessor to provide performance output of a PMBDCLM and DC servomotor. Based on the developed FEA models, velocity results have been utilized to provide feedrate levels for design of experiments (DOE). DOE has been conducted to provide force, tolerance, and surface finish data necessary for the performance comparison of a DC servo motor/ballscrew equipped CNC vertical milling machine and a PMBDCLM equipped CNC vertical milling machine. Based on the DOE, a knowledge base has been developed using force, tolerance, and surface finish data. Relationships between force, and spindle speed and feedrate with tolerance and surface finish indices were determined. A heuristic has been developed which represents a guide of applying a set of decisions through the knowledge base to provide a set of operating parameters that will meet user specified tolerance and surface finish requirements for given surfaces. Application of the developed heuristic to a milled part is illustrated. A PMBDCLM CNC retrofit for a conventional ballscrew feed drive system has also been developed to improve machine performance and cost