16,263 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
Matrix Product State Representation without explicit local Hilbert Space Truncation with Applications to the Sub-Ohmic Spin-Boson Model
We present an alternative to the conventional matrix product state
representation, which allows us to avoid the explicit local Hilbert space
truncation many numerical methods employ. Utilising chain mappings
corresponding to linear and logarithmic discretizations of the spin-boson model
onto a semi-infinite chain, we apply the new method to the sub-ohmic SBM. We
are able to reproduce many well-established features of the quantum phase
transition, such as the critical exponent 1/2 predicted by mean-field theory.
Via extrapolation of finite-chain results, we are able to determine the
infinite-chain critical couplings at which the transition occurs and, in
general, study the behaviour of the system well into the localised phase.Comment: 8 pages, 8 figure
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
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. --
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
Applications of Magnetic PsiDO Techniques to Space-adiabatic Perturbation Theory
In this review, we show how advances in the theory of magnetic
pseudodifferential operators (magnetic DO) can be put to good use in
space-adiabatic perturbation theory (SAPT). As a particular example, we extend
results of [PST03] to a more general class of magnetic fields: we consider a
single particle moving in a periodic potential which is subjectd to a weak and
slowly-varying electromagnetic field. In addition to the semiclassical
parameter \eps \ll 1 which quantifies the separation of spatial scales, we
explore the influence of additional parameters that allow us to selectively
switch off the magnetic field.
We find that even in the case of magnetic fields with components in
, e. g. for constant magnetic fields, the results of
Panati, Spohn and Teufel hold, i.e. to each isolated family of Bloch bands,
there exists an associated almost invariant subspace of and an
effective hamiltonian which generates the dynamics within this almost invariant
subspace. In case of an isolated non-degenerate Bloch band, the full quantum
dynamics can be approximated by the hamiltonian flow associated to the
semiclassical equations of motion found in [PST03].Comment: 32 page
A Numerical Study of Methods for Moist Atmospheric Flows: Compressible Equations
We investigate two common numerical techniques for integrating reversible
moist processes in atmospheric flows in the context of solving the fully
compressible Euler equations. The first is a one-step, coupled technique based
on using appropriate invariant variables such that terms resulting from phase
change are eliminated in the governing equations. In the second approach, which
is a two-step scheme, separate transport equations for liquid water and vapor
water are used, and no conversion between water vapor and liquid water is
allowed in the first step, while in the second step a saturation adjustment
procedure is performed that correctly allocates the water into its two phases
based on the Clausius-Clapeyron formula. The numerical techniques we describe
are first validated by comparing to a well-established benchmark problem.
Particular attention is then paid to the effect of changing the time scale at
which the moist variables are adjusted to the saturation requirements in two
different variations of the two-step scheme. This study is motivated by the
fact that when acoustic modes are integrated separately in time (neglecting
phase change related phenomena), or when sound-proof equations are integrated,
the time scale for imposing saturation adjustment is typically much larger than
the numerical one related to the acoustics
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
- …
