10,444 research outputs found
Supervised Release, Sex-Offender Treatment Programs, and Substantive Due Process
This Note argues that mandated PPG testing should be eliminated as a condition of federal supervised release. The test infringes on a constitutionally protected liberty interest against unwanted bodily intrusions and, as only the Second Circuit has held, any condition of supervised release that infringes on a constitutionally protected right may be mandated only where it is narrowly tailored to serve a compelling government interest. Because there are a number of viable, less intrusive alternatives, PPG testing as it stands today is not narrowly tailored enough to serve a compelling government interest
Low Visibility: The Fate of Air Traffic Control Privatization
This paper assesses plans to create an independent air traffic control corporation. While the plans being considered don't seem to offer the benefits that could result from privatization (the possible downsides are not being noted here), they also do not offer obvious resolutions to the problems currently faced by the air traffic control system. Since the specifics of a proposal are not currently available, it is not possible to provide a comprehensive assessment of its merits. However, any such proposal will not offer many of the benefits often claimed by advocates of privatization. There also do not appear to be any obvious fixes to the problems faced by the current system as a result of going the route of limited privatization.Notwithstanding a creditable safety record, the Federal Aviation Administration is under fire for mismanagement, particularly in the field of technology modernization. The airline trade association "Airlines for America" ("A4A") and its member carriers are calling for separation of the FAA's air traffic control ("ATC") operations into some kind of independent corporation.The chairman of the Committee on Transportation and Infrastructure of the U.S. House of Representatives, Rep. Bill Shuster (R-PA), has announced his intention to offer a plan resting on some questionable principles, to be discussed below.The appeals for reform typically reflect a yearning for system improvement, a lack of specifics, and a dearth of supporting arguments or data. Dorothy Robyn (2015) of the Brookings Institution noted that "a jaw-droppingly flawed variant on corporatization" has attracted support.It is possible a new air navigation service provider ("ANSP") could provide better service at reduced cost, but thus far no evidence for such a reform in the U.S. has been put forward, nor has any detailed plan been proposed
Higher-order neural network software for distortion invariant object recognition
The state-of-the-art in pattern recognition for such applications as automatic target recognition and industrial robotic vision relies on digital image processing. We present a higher-order neural network model and software which performs the complete feature extraction-pattern classification paradigm required for automatic pattern recognition. Using a third-order neural network, we demonstrate complete, 100 percent accurate invariance to distortions of scale, position, and in-plate rotation. In a higher-order neural network, feature extraction is built into the network, and does not have to be learned. Only the relatively simple classification step must be learned. This is key to achieving very rapid training. The training set is much smaller than with standard neural network software because the higher-order network only has to be shown one view of each object to be learned, not every possible view. The software and graphical user interface run on any Sun workstation. Results of the use of the neural software in autonomous robotic vision systems are presented. Such a system could have extensive application in robotic manufacturing
Accuracy of least-squares methods for the Navier-Stokes equations
Recently there has been substantial interest in least-squares finite element methods for velocity-vorticity-pressure formulations of the incompressible Navier-Stokes equations. The main cause for this interest is the fact that algorithms for the resulting discrete equations can be devised which require the solution of only symmetric, positive definite systems of algebraic equations. On the other hand, it is well-documented that methods using the vorticity as a primary variable often yield very poor approximations. Thus, here we study the accuracy of these methods through a series of computational experiments, and also comment on theoretical error estimates. It is found, despite the failure of standard methods for deriving error estimates, that computational evidence suggests that these methods are, at the least, nearly optimally accurate. Thus, in addition to the desirable matrix properties yielded by least-squares methods, one also obtains accurate approximations
A sufficient condition related to mistaken intuition about adjusted sums-of-squares in linear regression
We consider a misconception common among students of statistics involving "adjusted" and "unadjusted" sums-of-squares. While the presence of misconception has been noted before (e.g. Hamilton (1986)), we argue that it may be related to the language we use in describing the meaning of sums-of-squares. For linear regression with two independent variables, we then present a sufficient condition for SSR( X1 | X2 ) > SSR( X1 ) in terms of the signs of the sample correlations between pairs of predictor and response variables, and note how this sufficient condition may also be related to misconceptions held by some students of statistics. --
A Hybrid Adaptive Low-Mach-Number/Compressible Method: Euler Equations
Flows in which the primary features of interest do not rely on high-frequency
acoustic effects, but in which long-wavelength acoustics play a nontrivial
role, present a computational challenge. Integrating the entire domain with
low-Mach-number methods would remove all acoustic wave propagation, while
integrating the entire domain with the fully compressible equations can in some
cases be prohibitively expensive due to the CFL time step constraint. For
example, simulation of thermoacoustic instabilities might require fine
resolution of the fluid/chemistry interaction but not require fine resolution
of acoustic effects, yet one does not want to neglect the long-wavelength wave
propagation and its interaction with the larger domain. The present paper
introduces a new multi-level hybrid algorithm to address these types of
phenomena. In this new approach, the fully compressible Euler equations are
solved on the entire domain, potentially with local refinement, while their
low-Mach-number counterparts are solved on subregions of the domain with higher
spatial resolution. The finest of the compressible levels communicates
inhomogeneous divergence constraints to the coarsest of the low-Mach-number
levels, allowing the low-Mach-number levels to retain the long-wavelength
acoustics. The performance of the hybrid method is shown for a series of test
cases, including results from a simulation of the aeroacoustic propagation
generated from a Kelvin-Helmholtz instability in low-Mach-number mixing layers.
It is demonstrated that compared to a purely compressible approach, the hybrid
method allows time-steps two orders of magnitude larger at the finest level,
leading to an overall reduction of the computational time by a factor of 8
A Comparison of Absorption and Emission Line Abundances in the Nearby Damped Lyman-alpha Galaxy SBS 1543+593
We have used the Space Telescope Imaging Spectrograph (STIS) aboard HST to
measure a sulfur abundance of [S/H] = -0.41 +/-0.06 in the interstellar medium
(ISM) of the nearby damped Lyman-alpha (DLA) absorbing galaxy SBS 1543+593. A
direct comparison between this QSO absorption line abundance on the one hand,
and abundances measured from HII region emission line diagnostics on the other,
yield the same result: the abundance of sulfur in the neutral ISM is in good
agreement with that of oxygen measured in an HII region 3 kpc away. Our result
contrasts with those of other recent studies which have claimed
order-of-magnitude differences between HI (absorption) and HII (emission)
region abundances. We also derive a nickel abundance of [Ni/H] < -0.81, some
three times less than that of sulfur, and suggest that the depletion is due to
dust, although we cannot rule out an over-abundance of alpha-elements as the
cause of the lower metallicity. It is possible that our measure of [S/H] is
over-estimated if some SII arises in ionized gas; adopting a plausible star
formation rate for the galaxy along the line of sight, and a measurement of the
CII* 1335.7 absorption line detected from SBS 1543+593, we determine that the
metallicity is unlikely to be smaller than we derive by more than 0.25 dex. We
estimate that the cooling rate of the cool neutral medium is log [l_c (ergs
s^{-1} H atom^{-1})] = -27.0, the same value as that seen in the high redshift
DLA population.Comment: 31 pages; accepted for publication in the Ap
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