1,837 research outputs found

    Measurement of uncertainty costs with dynamic traffic simulations

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    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.

    Qualitative Supervision of Naval Diesel Engine Turbocharger Systems

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    FAC Intelligent Components and Instruments for Control Applications, Malaga, Spain, 1992This paper presents a qualitative model the diesel engine turbocharger system of a ship. The paper also shows how qualitative models can be use for an intelligent monitoring of the process concerned

    Nouveaux Orthoptères (Ensifera, Insecta) du Trias des Vosges (France)

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    Three new Orthoptera, Ensifera (Hagloidea and Gryllavoidea) from the Grés à Voltzia (Upper Buntsandstein, transition Lower / Middle Triassic) of the Vosges (France) are described based on forewings. Galliagryllavus vogesiacus n.gen., n.sp. (Gryllavidae) shows affinities with Gryllavus madygenicus SHAROV 1968 from the Triassic of Madygen (Kirghizistan). Triassoparacyrtophyllites bifurcatus n.gen., n.sp. (Tuphellidae) displays some similarities with Paracyrtophillites undulatus SHAROV 1968 from the Upper Jurassic of Karatau (Kazakhstan). Voltziahagla pseudoveinosa n.gen., n.sp. (Haglidae) seems close to the genus Archaboilus MARTYNOV 1937 from the Lower Jurassic of Shurab (Tadjikistan). These three Ensifera which belong to distinct families underscore the diversity of the Hagloidea and the Gryllavoidea at the boundary between the Lower and Middle Triassic. A cladistic study would be necessary to determine the phylogenetical relationships between the different families

    Distribution and origin of natural gas leakage in the Colorado Basin, offshore Argentina Margin, South America : seismic interpretation and 3D basin modelling

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    The detailed analysis of a dense 2D seismic reflection dataset and data from 8 exploration wells, allowed us to identify, map out and characterize possible indications of past and present-day hydrocarbon leakage (i.e. gas chimneys, gas pockets, and seafloor mounds and pockmarks) on the continental shelf and slope of the Colorado Basin, offshore Argentina, where Permian, Jurassic and Early Cretaceous source rocks are potentially present and may be currently mature. Identified gas leakage features, developed both in the syn-rift and post-rift successions, were also analysed in relation to the structural the stratigraphic elements of the basin. A family of seabed pockmarks, located close to an array of submarine channels, was identified on the distal slope of the basin. These pockmarks are overlying a series of sub-vertical to vertical seismic chimneys in the subsurface. A calibrated basin-wide 3D petroleum system model comprising generation and migration of hydrocarbons was carried out and compared with the observations from the seismic analysis. Preliminary results from this model indicate that although synrift and early Cretaceous source rock (SR) intervals may be depleted in the central areas of the basin, an active kitchen from the Aptian SR may be present below the slope areas. Hydrocarbon migration pathways predicted by the 3D model (Hybrid method) coincide with the interpreted seismic chimneys underlying the observed seabed slope pockmarks. Hence, our results indicate that thermogenic gas may be currently generated in the distal slope of the basin from mature early post-rift source rocks within the Early Cretaceous (Aptian) sequences and migrates vertically, due to seal failure, through the stratigraphic column. This migrating thermogenic gas is feeding the seafloor pockmarks identified in the distal slope of the basin, although up-dip lateral migration along stratigraphic layers to the more proximal slope areas cannot be ruled out. The present work represents the first published study integrating detailed seismic analysis and 3D basin modelling linking observed gas-leakage indicators and associated seepage pathways, to their relative abundance, distribution and feeding systems offshore Argentina's continental margin

    Dynamic contrast-enhanced and diffusion-weighted MRI for early detection of tumoral changes in single-dose and fractionated radiotherapy: evaluation in a rat rhabdomyosarcoma model

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    We aimed to examine different intratumoral changes after single-dose and fractionated radiotherapy, using diffusion-weighted (DW) and dynamic contrast-enhanced (DCE) MRI in a rat rhabdomyosarcoma model. Four WAG/Rij rats with rhabdomyosarcomas in the flanks received single-dose radiotherapy of 8 Gy, and four others underwent fractionated radiotherapy (five times 3 Gy). In rats receiving single-dose radiotherapy, a significant perfusion decrease was found in the first 2 days post-treatment, with slow recuperation afterwards. No substantial diffusion changes could be seen; tumor growth delay was 12 days. The rats undergoing fractionated radiotherapy showed a similar perfusion decrease early after the treatment. However, a very strong increase in apparent diffusion coefficient occurred in the first 10 days; growth delay was 18 days. DW-MRI and DCE-MRI can be used to show early tumoral changes induced by radiotherapy. Single-dose and fractionated radiotherapy induce an immediate perfusion effect, while the latter induces more intratumoral necrosis

    Topological expansion of beta-ensemble model and quantum algebraic geometry in the sectorwise approach

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    We solve the loop equations of the β\beta-ensemble model analogously to the solution found for the Hermitian matrices β=1\beta=1. For \beta=1,thesolutionwasexpressedusingthealgebraicspectralcurveofequation, the solution was expressed using the algebraic spectral curve of equation y^2=U(x).Forarbitrary. For arbitrary \beta,thespectralcurveconvertsintoaSchro¨dingerequation, the spectral curve converts into a Schr\"odinger equation ((\hbar\partial)^2-U(x))\psi(x)=0with with \hbar\propto (\sqrt\beta-1/\sqrt\beta)/N.Thispaperissimilartothesisterpaper I,inparticular,allthemainingredientsspecificforthealgebraicsolutionoftheproblemremainthesame,butherewepresentthesecondapproachtofindingasolutionofloopequationsusingsectorwisedefinitionofresolvents.Beingtechnicallymoreinvolved,itallowsdefiningconsistentlytheBcyclestructureoftheobtainedquantumalgebraiccurve(aDmoduleoftheform. This paper is similar to the sister paper~I, in particular, all the main ingredients specific for the algebraic solution of the problem remain the same, but here we present the second approach to finding a solution of loop equations using sectorwise definition of resolvents. Being technically more involved, it allows defining consistently the B-cycle structure of the obtained quantum algebraic curve (a D-module of the form y^2-U(x),where, where [y,x]=\hbar)andtoconstructexplicitlythecorrelationfunctionsandthecorrespondingsymplecticinvariants) and to construct explicitly the correlation functions and the corresponding symplectic invariants F_h,orthetermsofthefreeenergy,in1/N2, or the terms of the free energy, in 1/N^2-expansion at arbitrary \hbar. The set of "flat" coordinates comprises the potential times tkt_k and the occupation numbers \widetilde{\epsilon}_\alpha.WedefineandinvestigatethepropertiesoftheAandBcycles,formsof1st,2ndand3rdkind,andtheRiemannbilinearidentities.Weusetheseidentitiestofindexplicitlythesingularpartof. We define and investigate the properties of the A- and B-cycles, forms of 1st, 2nd and 3rd kind, and the Riemann bilinear identities. We use these identities to find explicitly the singular part of \mathcal F_0thatdependsexclusivelyon that depends exclusively on \widetilde{\epsilon}_\alpha$.Comment: 58 pages, 7 figure
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