27,651 research outputs found
Single-shot carrier-envelope phase determination of long superintense laser pulses
The impact of the carrier-envelope phase (CEP) of an intense multi-cycle
laser pulse on the radiation of an electron beam during nonlinear Compton
scattering is investigated. An interaction regime of the electron beam
counterpropagating to the laser pulse is employed, when pronounced high-energy
x-ray double peaks emerge at different angles near the backward direction
relative to the initial electron motion. This is achieved in the relativistic
interaction domain, with the additional requirements that the electron energy
is much lower than that necessary for the electron reflection condition at the
laser peak, and the stochasticity effects in the photon emission are weak. The
asymmetry parameter of the double peaks in the angular radiation distribution
is shown to serve as a sensitive and uniform measure for the CEP of the laser
pulse. The method demonstrates unprecedented sensitivity to subtle CEP-effects
up to 10-cycle laser pulses and can be applied for the characterization of
extremely strong laser pulses in present and near future laser facilities
Minimum Sparsity of Unobservable Power Network Attacks
Physical security of power networks under power injection attacks that alter
generation and loads is studied. The system operator employs Phasor Measurement
Units (PMUs) for detecting such attacks, while attackers devise attacks that
are unobservable by such PMU networks. It is shown that, given the PMU
locations, the solution to finding the sparsest unobservable attacks has a
simple form with probability one, namely, , where
is defined as the vulnerable vertex connectivity of an augmented
graph. The constructive proof allows one to find the entire set of the sparsest
unobservable attacks in polynomial time. Furthermore, a notion of the potential
impact of unobservable attacks is introduced. With optimized PMU deployment,
the sparsest unobservable attacks and their potential impact as functions of
the number of PMUs are evaluated numerically for the IEEE 30, 57, 118 and
300-bus systems and the Polish 2383, 2737 and 3012-bus systems. It is observed
that, as more PMUs are added, the maximum potential impact among all the
sparsest unobservable attacks drops quickly until it reaches the minimum
sparsity.Comment: submitted to IEEE Transactions on Automatic Contro
Fault diagnosis and fault-tolerant control for nonlinear systems with linear output structure
Article describes the process of fault diagnosis and fault-tolerant control for nonlinear systems with linear output structure
Cumulative Prospect Theory Based Dynamic Pricing for Shared Mobility on Demand Services
Cumulative Prospect Theory (CPT) is a modeling tool widely used in behavioral
economics and cognitive psychology that captures subjective decision making of
individuals under risk or uncertainty. In this paper, we propose a dynamic
pricing strategy for Shared Mobility on Demand Services (SMoDSs) using a
passenger behavioral model based on CPT. This dynamic pricing strategy together
with dynamic routing via a constrained optimization algorithm that we have
developed earlier, provide a complete solution customized for SMoDS of
multi-passenger transportation. The basic principles of CPT and the derivation
of the passenger behavioral model in the SMoDS context are described in detail.
The implications of CPT on dynamic pricing of the SMoDS are delineated using
computational experiments involving passenger preferences. These implications
include interpretation of the classic fourfold pattern of risk attitudes,
strong risk aversion over mixed prospects, and behavioral preferences of self
reference. Overall, it is argued that the use of the CPT framework corresponds
to a crucial building block in designing socio-technical systems by allowing
quantification of subjective decision making under risk or uncertainty that is
perceived to be otherwise qualitative.Comment: 17 pages, 6 figures, and has been accepted for publication at the
58th Annual Conference on Decision and Control, 201
Discounting Spotted Apples: Investigating Consumersï¾’ Willingness to Accept Cosmetic Damage in an Organic Product
Organic producers have limited methods of avoiding plant diseases that result in cosmetic damage to produce. Therefore, the appearance of organic produce is often less than perfect. We use an experimental auction to investigate how cosmetic damage affects consumersï¾’ willingness to pay for organic apples. We find that 75% of the participants are willing to pay more for organic than for conventional apples given identical appearance. However, at the first sight of any imperfection in the appearance of the organic apples, this segment is significantly reduced. Furthermore, we find that there is a significant effect of interaction between cosmetic damage and product methods. Even though most consumers say they buy organic products to avoid pesticides, we find that cosmetic damage has a larger impact on the willingness to pay for organic apples than for conventional apples.
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