6,070 research outputs found
Rethinking Presidential Eligibility
Many aspiring American Presidents have had their candidacies challenged for failing to meet the Constitution’s eligibility requirements. Although none of these challenges have ever been successful, they have sapped campaigns of valuable resources and posed a threat to several ambitious men. This Article examines several notable presidential eligibility challenges and explains why they have often been unsuccessful. The literature on presidential eligibility traditionally has focused on the Eligibility Clause, which enumerates the age, residency, and citizenship requirements that a President must satisfy before taking office. By contrast, very little of it examines how a challenge to one’s candidacy impacts a presidential campaign. This Article seeks to fill this gap. It also offers a modest proposal: Congress should pass legislation defining exactly who is eligible to be President and also implement procedural rules that would expedite presidential eligibility cases for review to the Supreme Court
Parametric versus nonparametric: the fitness coefficient
The fitness coefficient, introduced in this paper, results from a competition
between parametric and nonparametric density estimators within the likelihood
of the data. As illustrated on several real datasets, the fitness coefficient
generally agrees with p-values but is easier to compute and interpret. Namely,
the fitness coefficient can be interpreted as the proportion of data coming
from the parametric model. Moreover, the fitness coefficient can be used to
build a semiparamteric compromise which improves inference over the parametric
and nonparametric approaches. From a theoretical perspective, the fitness
coefficient is shown to converge in probability to one if the model is true and
to zero if the model is false. From a practical perspective, the utility of the
fitness coefficient is illustrated on real and simulated datasets
Decentralized event-triggered control over wireless sensor/actuator networks
In recent years we have witnessed a move of the major industrial automation
providers into the wireless domain. While most of these companies already offer
wireless products for measurement and monitoring purposes, the ultimate goal is
to be able to close feedback loops over wireless networks interconnecting
sensors, computation devices, and actuators. In this paper we present a
decentralized event-triggered implementation, over sensor/actuator networks, of
centralized nonlinear controllers. Event-triggered control has been recently
proposed as an alternative to the more traditional periodic execution of
control tasks. In a typical event-triggered implementation, the control signals
are kept constant until the violation of a condition on the state of the plant
triggers the re-computation of the control signals. The possibility of reducing
the number of re-computations, and thus of transmissions, while guaranteeing
desired levels of performance makes event-triggered control very appealing in
the context of sensor/actuator networks. In these systems the communication
network is a shared resource and event-triggered implementations of control
laws offer a flexible way to reduce network utilization. Moreover reducing the
number of times that a feedback control law is executed implies a reduction in
transmissions and thus a reduction in energy expenditures of battery powered
wireless sensor nodes.Comment: 13 pages, 3 figures, journal submissio
Isochronous Partitions for Region-Based Self-Triggered Control
In this work, we propose a region-based self-triggered control (STC) scheme
for nonlinear systems. The state space is partitioned into a finite number of
regions, each of which is associated to a uniform inter-event time. The
controller, at each sampling time instant, checks to which region does the
current state belong, and correspondingly decides the next sampling time
instant. To derive the regions along with their corresponding inter-event
times, we use approximations of isochronous manifolds, a notion firstly
introduced in [1]. This work addresses some theoretical issues of [1] and
proposes an effective computational approach that generates approximations of
isochronous manifolds, thus enabling the region-based STC scheme. The
efficiency of both our theoretical results and the proposed algorithm are
demonstrated through simulation examples
Surface defects and temperature on atomic friction
We present a theoretical study of the effect of surface defects on atomic
friction in the stick-slip dynamical regime of a minimalistic model. We focus
on how the presence of defects and temperature change the average properties of
the system. We have identified two main mechanisms which modify the mean
friction force of the system when defects are considered. As expected, defects
change locally the potential profile and thus affect the friction force. But
the presence of defects also changes the probability distribution function of
the tip slip length and thus the mean friction force. We corroborated both
effects for different values of temperature, external load, dragging velocity
and damping. We show also a comparison of the effects of surface defects and
surface disorder on the dynamics of the system
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