6,527 research outputs found
Spending Money to Make Money: CBO Scoring of Secondary Effects
Increased funding for federal enforcement and program integrity often pays for itself through what are called secondary effects. In some cases, the funding allows agencies to collect more revenue; in others, it enables agencies to reduce the amount of money lost to waste, fraud, and abuse. But despite these benefits, Congress regularly underfunds agency enforcement and program integrity. This Note argues that the problem of underfunding arises out of a little discussed feature of the congressional budget process: the scorekeeping guidelines. As a general matter, the scorekeeping guidelines tell the Congressional Budget Office (CBO) how to estimate or score the cost of legislation
Using Rollback Avoidance to Mitigate Failures in Next-Generation Extreme-Scale Systems
High-performance computing (HPC) systems enable scientists to numerically model complex phenomena in many important physical systems. The next major milestone in the development of HPC systems is the construction of the first supercomputer capable executing more than an exaflop, 10^18 floating point operations per second. On systems of this scale, failures will occur much more frequently than on current systems. As a result, resilience is a key obstacle to building next-generation extreme-scale systems. Coordinated checkpointing is currently the most widely-used mechanism for handling failures on HPC systems. Although coordinated checkpointing remains effective on current systems, increasing the scale of today\u27s systems to build next-generation systems will increase the cost of fault tolerance as more and more time is taken away from the application to protect against or recover from failure. Rollback avoidance techniques seek to mitigate the cost of checkpoint/restart by allowing an application to continue its execution rather than rolling back to an earlier checkpoint when failures occur. These techniques include failure prediction and preventive migration, replicated computation, fault-tolerant algorithms, and software-based memory fault correction. In this thesis, I examine how rollback avoidance techniques can be used to address failures on extreme-scale systems. Using a combination of analytic modeling and simulation, I evaluate the potential impact of rollback avoidance on these systems. I then present a novel rollback avoidance technique that exploits similarities in application memory. Finally, I examine the feasibility of using this technique to protect against memory faults in kernel memory
Petawatt laser absorption bounded
The interaction of petawatt () lasers with solid matter
forms the basis for advanced scientific applications such as table-top particle
accelerators, ultrafast imaging systems and laser fusion. Key metrics for these
applications relate to absorption, yet conditions in this regime are so
nonlinear that it is often impossible to know the fraction of absorbed light
, and even the range of is unknown. Here using a relativistic
Rankine-Hugoniot-like analysis, we show for the first time that exhibits a
theoretical maximum and minimum. These bounds constrain nonlinear absorption
mechanisms across the petawatt regime, forbidding high absorption values at low
laser power and low absorption values at high laser power. For applications
needing to circumvent the absorption bounds, these results will accelerate a
shift from solid targets, towards structured and multilayer targets, and lead
the development of new materials
Reform at Risk — Mandating Participation in Alternative Payment Plans
In an ambitious effort to slow the growth of health care costs, the Affordable Care Act created the Center for Medicare and Medicaid Innovation (CMMI) and armed it with broad authority to test new approaches to reimbursement for health care (payment models) and delivery-system reforms. CMMI was meant to be the government’s innovation laboratory for health care: an entity with the independence to break with past practices and the power to experiment with bold new approaches. Over the past year, however, the Department of Health and Human Services (HHS) has quietly hobbled CMMI, imperiling its ability to generate meaningful data on strategies for reducing spending on Medicare and Medicaid
Polarization proximity effect in isolator crystal pairs
We experimentally studied the polarization dynamics (orientation and
ellipticity) of near infrared light transmitted through magnetooptic Yttrium
Iron Garnet crystal pairs using a modified balanced detection scheme. When the
pair separation is in the sub-millimeter range, we observed a proximity effect
in which the saturation field is reduced by up to 20%. 1D magnetostatic
calculations suggest that the proximity effect originates from magnetostatic
interactions between the dipole moments of the isolator crystals. This
substantial reduction of the saturation field is potentially useful for the
realization of low-power integrated magneto-optical devices.Comment: submitted to Optics Letter
ADVISE: Symbolism and External Knowledge for Decoding Advertisements
In order to convey the most content in their limited space, advertisements
embed references to outside knowledge via symbolism. For example, a motorcycle
stands for adventure (a positive property the ad wants associated with the
product being sold), and a gun stands for danger (a negative property to
dissuade viewers from undesirable behaviors). We show how to use symbolic
references to better understand the meaning of an ad. We further show how
anchoring ad understanding in general-purpose object recognition and image
captioning improves results. We formulate the ad understanding task as matching
the ad image to human-generated statements that describe the action that the ad
prompts, and the rationale it provides for taking this action. Our proposed
method outperforms the state of the art on this task, and on an alternative
formulation of question-answering on ads. We show additional applications of
our learned representations for matching ads to slogans, and clustering ads
according to their topic, without extra training.Comment: To appear, Proceedings of the European Conference on Computer Vision
(ECCV
Evaluation of animal control measures on pet demographics in Santa Clara County, California, 1993–2006
The measurable benefits of animal control programs are unknown and the aim of this study was to determine the impact of these programs on pet population changes. A prospective cross-sectional study of 1000 households was implemented in 2005 to evaluate characteristics of the owned and unowned population of dogs and cats in Santa Clara County, California. The same population was previously studied 12 years earlier. During this time period, the county instituted in 1994 and then subsequently disestablished a municipal spay/neuter voucher program for cats. Dog intakes declined from 1992–2005, as they similarly did for an adjacent county (San Mateo). However, cat intakes declined significantly more in Santa Clara County than San Mateo, with an average annual decline of approximately 700 cats for the 12 year period. Time series analysis showed a greater than expected decline in the number of cats surrendered to shelters in Santa Clara County during the years the voucher program was in effect (1994–2005). The net savings to the county by reducing the number of cat shelter intakes was estimated at approximately $1.5 million. The measurable benefits of animal control programs are unknown and the aim of this study was to determine the impact of these programs on pet population changes
Research of the active reflector antenna using laser angle metrology system
Active reflector is one of the key technologies for constructing large
telescopes, especially for the millimeter/sub-millimeter radio telescopes. This
article introduces a new efficient laser angle metrology system for the active
reflector antenna of the large radio telescopes, with a plenty of active
reflector experiments mainly about the detecting precisions and the maintaining
of the surface shape in real time, on the 65-meter radio telescope prototype
constructed by Nanjing Institute of Astronomical Optics and Technology (NIAOT).
The test results indicate that the accuracy of the surface shape segmenting and
maintaining is up to micron dimension, and the time-response can be of the
order of minutes. Therefore, it is proved to be workable for the sub-millimeter
radio telescopes.Comment: 10 pages, 15 figure
Quantum \v{C}erenkov Radiation: Spectral Cutoffs and the Role of Spin and Orbital Angular Momentum
We show that the well-known \v{C}erenkov Effect contains new phenomena
arising from the quantum nature of charged particles. The \v{C}erenkov
transition amplitudes allow coupling between the charged particle and the
emitted photon through their orbital angular momentum (OAM) and spin, by
scattering into preferred angles and polarizations. Importantly, the spectral
response reveals a discontinuity immediately below a frequency cutoff that can
occur in the optical region. Specifically, with proper shaping of electron
beams (ebeams), we predict that the traditional \v{C}erenkov radiation angle
splits into two distinctive cones of photonic shockwaves. One of the shockwaves
can move along a backward cone, otherwise considered impossible for
\v{C}erenkov radiation in ordinary matter. Our findings are observable for
ebeams with realistic parameters, offering new applications including novel
quantum optics sources, and open a new realm for \v{C}erenkov detectors
involving the spin and orbital angular momentum of charged particles.Comment: 27 pages, 3 figure
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