14,843 research outputs found
A high resolution spectroscopic study of the oxygen molecule
A high resolution spectrometer which incorporates a narrow line width tunable dye laser was used to make absorption profiles of 57 spectral lines in the Oxygen A-Band at pressures up to one atmosphere in pure O2. The observed line profiles are compared to the Voigt, and a collisionally narrowed, profile using a least squares fitting procedure. The collisionally narrowed profile compares more favorable to the observed profiles. Values of the line strengths and self broadening coeffiencients, determined from the least square fitting process, are presented in tabular form. It is found that the experssion by Watson are in closest agreement with the experimentally determined strengths. The self broadening coefficients are compared with the measurements of several other investigators
Illumination in binaries
We give a simple, but accurate method that can be used to account for
illumination in compact binary systems which have a low-mass companion, even if
spherically symmetric illumination of the secondary star (not necessarily on
the main sequence) is not assumed. This is done by introducing a multiplicative
factor Phi in the Stefan-Boltzmann surface boundary condition, which accounts
for the blocking of the intrinsic secondary flux by X-ray heating of the
photospheric layers. Numerical fits and tables for Phi are given for
unperturbed effective temperatures in the range 2500 - 5600 K and log g in the
range 1.0 - 5.0Comment: 5 pages, 3 figures. Accepted for publication in Astronomy and
Astrophysics Supplement Serie
Free-Knot Spline Approximation of Stochastic Processes
We study optimal approximation of stochastic processes by polynomial splines
with free knots. The number of free knots is either a priori fixed or may
depend on the particular trajectory. For the -fold integrated Wiener process
as well as for scalar diffusion processes we determine the asymptotic behavior
of the average -distance to the splines spaces, as the (expected) number
of free knots tends to infinity.Comment: 23 page
Weight estimation techniques for composite airplanes in general aviation industry
Currently available weight estimation methods for general aviation airplanes were investigated. New equations with explicit material properties were developed for the weight estimation of aircraft components such as wing, fuselage and empennage. Regression analysis was applied to the basic equations for a data base of twelve airplanes to determine the coefficients. The resulting equations can be used to predict the component weights of either metallic or composite airplanes
Low-powered incentives
We study low-powered incentives in a model that captures important features of workplaces in which incentive-pay approaches are minimally relevant. Our motivation is that incentive pay, while not rare, is clearly far less common than are agency problems: many firms with agency problems nonetheless pay fixed compensation and offer continued employment to all but those workers judged "unsatisfactory" according to largely subjective criteria. We find that low-powered incentives can achieve efficient outcomes in simple workplaces and function surprisingly well even when the environment is characterized by unobservable performance heterogeneity and a high degree of complementarity among workers.Wages
Economic models of employee motivation
Workers, being human beings, present employers with a range of tricky problems. Humans, unlike filing cabinets, can be crooked, subversive, surly, or indolent, even if they are paid on time. In this article we explore economists' main models of how compensation is used to address employee motivation and how these models help to explain puzzling features of the labor market.Wages ; Management ; Labor market
Valuable jobs and uncertainty
Little attention has been given to the link between variation in a firm's circumstances and the resolution of agency problems that pervade the relationship between a firm and its employees. We construct stochastic versions of standard efficiency-wage and performance-bonding models and find that this connection has important and apparently inescapable consequences. Compensation levels depend on characteristics of the firm. The possibility of the firm's exit drive an important counterfactual prediction in both classes of model: compensation rises in dying firms. This result illustrates the need for careful attention to the circumstances under which valuable jobs are liquidated.Job analysis ; Employment (Economic theory) ; Labor turnover
Strength, Width, and Pressure Shift Measurements of 54 Lines in the Oxygen A-Band
The absorption band of molecular oxygen, centered at 760]en1] nm, is the atmospheric absorber for the Differential Absorption Lidar (DIAL) systems used to measure atmospheric temperature, pressure, and density. To provide accurate line parameters for such systems, a careful spectroscopic study was made of the A-band, with measurements of line strengths, widths, pressure-induced frequency shifts, and collisional narrowing effects. The width and shift parameters were measured over a temperature range of -20 to 100 C so that the temperature dependence of these parameters can also be determined. To analyze the results, a least-squares fiting routine was written to fit standard line profiles to the observed profiles. These measurements, which include the first observations of pressure shifts and collisional narrowing in the band, are an important contribution to lidar system utilizing the A-band
Does Size Matter? School Consolidation Policy Issues in Arkansas
Providing a reasonable education for all students in Arkansas is a legal responsibility explicitly mandated by the state’s constitution. Consistent with the long-standing American tradition of “grassroots” control of education, public schools in all states are funded and managed first and foremost at the local level. The federal government can and does enact legislation with which schools must conform. Directly or indirectly, federal mandates provide significant amounts of monies to support particular types of school services and programming. But ultimate responsibility for financing and operating schools devolves on state government. In Arkansas, it has been held, the state must provide “a general, suitable, and efficient system of free public schools” (Lakeview v. Huckabee, 2001)
Towards More Data-Aware Application Integration (extended version)
Although most business application data is stored in relational databases,
programming languages and wire formats in integration middleware systems are
not table-centric. Due to costly format conversions, data-shipments and faster
computation, the trend is to "push-down" the integration operations closer to
the storage representation.
We address the alternative case of defining declarative, table-centric
integration semantics within standard integration systems. For that, we replace
the current operator implementations for the well-known Enterprise Integration
Patterns by equivalent "in-memory" table processing, and show a practical
realization in a conventional integration system for a non-reliable,
"data-intensive" messaging example. The results of the runtime analysis show
that table-centric processing is promising already in standard, "single-record"
message routing and transformations, and can potentially excel the message
throughput for "multi-record" table messages.Comment: 18 Pages, extended version of the contribution to British
International Conference on Databases (BICOD), 2015, Edinburgh, Scotlan
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