Measurement of uncertainty costs with dynamic traffic simulations

Non-recurrent congestion in transportation networks occurs as a consequence of stochastic factors affecting demand and supply. Intelligent Transportation Systems such as Advanced Traveler Information Systems (ATIS) and Advanced Traffic Management Systems (ATMS) are designed in order to reduce the impacts of non-recurrent congestion by providing information to a fraction of users or by controlling the variability of traffic flows. For these reasons, the design of ATIS and ATMS requires reliable forecast of non-recurrent congestion. This paper proposes a new method to measure the impacts of non-recurrent congestion on travel costs by taking risk aversion into account. The traffic model is based on the dynamic traffic simulations model METROPOLIS. Incidents are generated randomly by reducing the capacity of the network. Users can instantaneously adapt to the unexpected travel conditions or can also change their behavior via a day-to-day adjustment process. Comparisons with incident-free simulations provide a benchmark for potential travel time savings that can be brought in by a state-of-the-art information system. We measure the impact of variable travel conditions by describing the willingness to pay to avoid risky or unreliable journeys. Indeed, for risk averse drivers, any uncertainty corresponds to a utility loss. This utility loss is computed for several levels of network disruption. The main results of the paper is that the utility loss due to uncertainty is of the same order of magnitude as the total travel costs.

The influence of information availability on the choice of destination

We set a framework where an individual has to choose one among a set of spatially distributed activities. The individual knows the price of each activity, as well as the distance to reach it. She has either full or zero information about each activity's quality. Qualities are modeled by i.i.d. random variables. Under the full information regime, the individual knows the realizations of the qualities; while under the no information regime, she only knows the distribution of the qualities. In that case, she can decide either ex ante, or en route, how many activities to patronize. We analyze the impact of information availability on the choice process, on the distance the individual covers, and on the individual's expected utility. In this framework, more information yields longer distance traveled, but also higher utility. We compute the individual's willingness to pay for information. Finally, we show that providing information may decrease the individual's benefit when congestion arises.travel demand, search, logit, information regimes, value of information, differentiation

Recent results from Fermi-LAT

We highlight the most important recent results from the Fermi Large Area Telescope (LAT). The latest source catalog (2FGL) is briefly discussed and several recent results on DM indirect searches from different targets are summarized. Finally, various results on the cosmic rays direct detection are presented

The First Fermi-LAT SNR Catalog SNR and Cosmic Ray Implications

Galactic cosmic ray (CRs) sources, classically proposed to be Supernova Remnants (SNRs), must meet the energetic particle content required by direct measurements of high energy CRs. Indirect gamma-ray measurements of SNRs with the Fermi Large Area Telescope (LAT) have now shown directly that at least three SNRs accelerate protons. With the first Fermi LAT SNR Catalog, we have systematically characterized the GeV gamma-rays emitted by 279 SNRs known primarily from radio surveys. We present these sources in a multiwavelength context, including studies of correlations between GeV and radio size, flux, and index, TeV index, and age and environment tracers, in order to better understand effects of evolution and environment on the GeV emission. We show that previously sufficient models of SNRs' GeV emission no longer adequately describe the data. To address the question of CR origins, we also examine the SNRs' maximal CR contribution assuming the GeV emission arises solely from proton interactions. Improved breadth and quality of multiwavelength data, including distances and local densities, and more, higher resolution gamma-ray data with correspondingly improved Galactic diffuse models will strengthen this constraint.Comment: 8 pages, 10 figures; in Proceedings of the 34th International Cosmic Ray Conference (ICRC 2015), The Hague (The Netherlands

Developments of the pinned photodiode terahertz rectifier

This paper presents we presents a development of the structure of the pinned photodiode terahertz rectifier, in which the metal whisker of the antenna is separated from the semiconductor by a silane oxide layer, in order to reduce the surface defectiveness. The rectifies is the basic component of an image detection system based on the structure of actual CMOS image detectors. The structure combines a nano-antenna, fabricated on the top of a standard image sensor, the rectifier, and the readout electronics. The rectifier device proposed has vertical extension of some tenths of nanometers, can be created at the foot of the nano-whisker at the end of the terahertz antenna, above the storage well

Entanglement detection in hybrid optomechanical systems

We study a device formed by a Bose Einstein condensate (BEC) coupled to the field of a cavity with a moving end-mirror and find a working point such that the mirror-light entanglement is reproduced by the BEC-light quantum correlations. This provides an experimentally viable tool for inferring mirror-light entanglement with only a limited set of assumptions. We prove the existence of tripartite entanglement in the hybrid device, persisting up to temperatures of a few milli-Kelvin, and discuss a scheme to detect it.Comment: 6 pages, 7 figures, published versio

Cavity-aided quantum parameter estimation in a bosonic double-well Josephson junction

We describe an apparatus designed to make non-demolition measurements on a Bose-Einstein condensate (BEC) trapped in a double-well optical cavity. This apparatus contains, as well as the bosonic gas and the trap, an optical cavity. We show how the interaction between the light and the atoms, under appropriate conditions, can allow for a weakly disturbing yet highly precise measurement of the population imbalance between the two wells and its variance. We show that the setting is well suited for the implementation of quantum-limited estimation strategies for the inference of the key parameters defining the evolution of the atomic system and based on measurements performed on the cavity field. This would enable {\it de facto} Hamiltonian diagnosis via a highly controllable quantum probe.Comment: 8 pages, 5 figures, RevTeX4; Accepted for publication in Phys. Rev.