Compensating Wage Differentials for Mandatory Overtime

Our paper estimates the extent to which employees are compensated for an unfavorable job characteristic, being required to accept mandatory assignment of overtime, by receiving higher straight-time wages. Our estimating equations are derived from a model in which wage rates and the existence of mandatory assignment of overtime are jointly determined in the market by the interaction of employee and employer preferences. While - on average, we do not observe the existence of a compensating wage differential for mandatory overtime, we do observe the existence of such differentials for unionized workers and workers with only a few years experience at a firm. Given any estimated compensating wage differential for an unfavorable working condition, one must decide whether its magnitude is sufficiently large to allow one to conclude that the differential fully compensates workers for the disutility of being subject to the unfavorable working condition. We develop and illustrate a methodology that can be used to answer this question, at least for the case of mandatory overtime provisions and other rules that restrict employees' choice of hours.

Compliance with the Overtime Pay Provisions of the Fair Labor Standards Act

Our paper presents a methodology that can be used to estimate the extent of noncompliance with the overtime pay provisions of the Fair Labor Standards Act (FLSA). The methodology is applied to data from the May 1978 Current Population Survey and the 1977 Michigan Quality of Employment Survey. These data suggest that the fraction of covered workers working overtime who fail to receive a premium of at least time and a half, as called for by the legislation, is in the range of 25 percent. They also suggest that the extent of noncompliance is greater in those industries in which size class exemptions to the legislation exist (retail trade and selected service industries). Finally, probit analyses of the determinants of noncompliance suggest that decisions about whether to comply with the overtime provisions of the FLSA are at least partially based on the associated benefits and costs.

Stacking-based visualization of trajectory attribute data

Visualizing trajectory attribute data is challenging because it involves showing the trajectories in their spatio-temporal context as well as the attribute values associated with the individual points of trajectories. Previous work on trajectory visualization addresses selected aspects of this problem, but not all of them. We present a novel approach to visualizing trajectory attribute data. Our solution covers space, time, and attribute values. Based on an analysis of relevant visualization tasks, we designed the visualization solution around the principle of stacking trajectory bands. The core of our approach is a hybrid 2D/3D display. A 2D map serves as a reference for the spatial context, and the trajectories are visualized as stacked 3D trajectory bands along which attribute values are encoded by color. Time is integrated through appropriate ordering of bands and through a dynamic query mechanism that feeds temporally aggregated information to a circular time display. An additional 2D time graph shows temporal information in full detail by stacking 2D trajectory bands. Our solution is equipped with analytical and interactive mechanisms for selecting and ordering of trajectories, and adjusting the color mapping, as well as coordinated highlighting and dedicated 3D navigation. We demonstrate the usefulness of our novel visualization by three examples related to radiation surveillance, traffic analysis, and maritime navigation. User feedback obtained in a small experiment indicates that our hybrid 2D/3D solution can be operated quite well

Automatic Derivation of Statistical Algorithms: The EM Family and Beyond

Machine learning has reached a point where many probabilistic methods can be understood as variations, extensions and combinations of a much smaller set of abstract themes, e.g., as different instances of the EM algorithm. This enables the systematic derivation of algorithms customized for different models. Here, we describe the AUTOBAYES system which takes a high-level statistical model specification, uses powerful symbolic techniques based on schema-based program synthesis and computer algebra to derive an efficient specialized algorithm for learning that model, and generates executable code implementing that algorithm. This capability is far beyond that of code collections such as Matlab toolboxes or even tools for model-independent optimization such as BUGS for Gibbs sampling: complex new algorithms can be generated without new programming, algorithms can be highly specialized and tightly crafted for the exact structure of the model and data, and efficient and commented code can be generated for different languages or systems. We present automatically-derived algorithms ranging from closed-form solutions of Bayesian textbook problems to recently-proposed EM algorithms for clustering, regression, and a multinomial form of PCA

Aerodynamic design of a free power turbine for a 75 KW gas turbine automotive engine

A single stage axial-flow turbine having a tip diameter of 15.41 centimeters was designed. The design specifications are given and the aerodynamic design procedure is described. The design includes the transition duct and the turbine exit diffuser. The aerodynamic information includes typical results of a parametric study, velocity diagrams, blade surface and wall velocities, and blade profile and wall coordinates

Subjective nature of Reality: The Metabrain and Schroedinger’s Cat

We show that according to quantum theory and special relativity that “objects” do not have independent existence or characteristics. We argue that reality consists of highly correlated but distinct streams of consciousness possibly created by a “metabrain”.

Iron single crystal growth from a lithium-rich melt

\alpha-Fe single crystals of rhombic dodecahedral habit were grown from a melt of Li$_{84}$N$_{12}$Fe$_{\sim 3}$. Crystals of several millimeter along a side form at temperatures around $T \approx 800^\circ$C. Upon further cooling the growth competes with the formation of Fe-doped Li$_3$N. The b.c.c. structure and good sample quality of \alpha-Fe single crystals were confirmed by X-ray and electron diffraction as well as magnetization measurements and chemical analysis. A nitrogen concentration of 90\,ppm was detected by means of carrier gas hot extraction. Scanning electron microscopy did not reveal any sign of iron nitride precipitates.Comment: 13 pages, 4 figure