3,886 research outputs found
A real delivery problem dealt with Monte Carlo techniques
[EN] In this paper we use Monte Carlo Techniques to deal with a real world delivery problem of a food company in Valencia (Spain). The problem is modeled as a set of 11 instances of the well known Vehicle Routing Problem, VRP, with additional time constraints. Given that VRP is a NP-hard problem, a heuristic algorithm, based on Monte Carlo techniques, is implemented. The solution proposed by this heuristic algorithm reaches distance and money savings of about 20% and 5% respectively.This research was partially supported by MICINN, Project MTM2013-43540-P and by UPV, Project Programa de Apoyo a la Investigación y Desarrollo de la UPV PAID-06-12.S577181Fernández de Córdoba, P., L.M. García-Raffi and J.M. Sanchis Llopis (1998), A heuristic algorithm based on Monte Carlo methods for the Rural Postman Problem.Computers and Op. Research,25, No. 12, pp. 1097–1106, 1998.Fernández de Córdoba, P. and L.M. García-Raffi, E. Nieto and J.M. Sanchis Llopis (1999a), Aplicación de técnicas Monte Carlo a un problema real de Rutas de Vehículos.Anales de Ingeniería, Colombia. In press.Fernández de Córdoba, P., L.M. García-Raffi and J.M. Sanchis Llopis (1999b), A Constructive Parallel Algorithm based on Monte Carlo techniques for Routing Problems, Submitted toParallel Computers.Laporte, G. (1992), The Vehicle Routing Problem: an overview of exact and approximate algorithms,European Journal of Operations Research,59, 345.Laporte, G., M. Desrochers and Y. Nobert (1985), “Optimal Routing under Capacity and Distance Restrictions.Operations Research,33, pp. 1050–1073.Laporte G. and Y. Nobert (1987), Exact algorithms for The Vehicle Routing Problem,Surveys in Combinatorial Optimization (S. Martello, G. Laporte, M. Minoux and C. Ribeiro Eds.). North-HollandAmsterdamMayado, A. (1998), Organización de los itinerarios de la flota de camiones de reparto de una sociedad cooperativa. Optimización mediante técnicas de simulación Monte Carlo. Proyecto Fin de Carrera. E.T.S.I.I. Universidad Politécnica de Valencia
SST-GATE: A dual mirror telescope for the Cherenkov Telescope Array
The Cherenkov Telescope Array (CTA) will be the world's first open
observatory for very high energy gamma-rays. Around a hundred telescopes of
different sizes will be used to detect the Cherenkov light that results from
gamma-ray induced air showers in the atmosphere. Amongst them, a large number
of Small Size Telescopes (SST), with a diameter of about 4 m, will assure an
unprecedented coverage of the high energy end of the electromagnetic spectrum
(above ~1TeV to beyond 100 TeV) and will open up a new window on the
non-thermal sky. Several concepts for the SST design are currently being
investigated with the aim of combining a large field of view (~9 degrees) with
a good resolution of the shower images, as well as minimizing costs. These
include a Davies-Cotton configuration with a Geiger-mode avalanche photodiode
(GAPD) based camera, as pioneered by FACT, and a novel and as yet untested
design based on the Schwarzschild-Couder configuration, which uses a secondary
mirror to reduce the plate-scale and to allow for a wide field of view with a
light-weight camera, e.g. using GAPDs or multi-anode photomultipliers. One
objective of the GATE (Gamma-ray Telescope Elements) programme is to build one
of the first Schwarzschild-Couder prototypes and to evaluate its performance.
The construction of the SST-GATE prototype on the campus of the Paris
Observatory in Meudon is under way. We report on the current status of the
project and provide details of the opto-mechanical design of the prototype, the
development of its control software, and simulations of its expected
performance.Comment: In Proceedings of the 33rd International Cosmic Ray Conference
(ICRC2013), Rio de Janeiro (Brazil). All CTA contributions at arXiv:1307.223
JPCam: A 1.2Gpixel camera for the J-PAS survey
JPCam is a 14-CCD mosaic camera, using the new e2v 9k-by-9k 10microm-pixel
16-channel detectors, to be deployed on a dedicated 2.55m wide-field telescope
at the OAJ (Observatorio Astrofisico de Javalambre) in Aragon, Spain. The
camera is designed to perform a Baryon Acoustic Oscillations (BAO) survey of
the northern sky. The J-PAS survey strategy will use 54 relatively narrow-band
(~13.8nm) filters equi-spaced between 370 and 920nm plus 3 broad-band filters
to achieve unprecedented photometric red-shift accuracies for faint galaxies
over ~8000 square degrees of sky. The cryostat, detector mosaic and read
electronics is being supplied by e2v under contract to J-PAS while the
mechanical structure, housing the shutter and filter assembly, is being
designed and constructed by a Brazilian consortium led by INPE (Instituto
Nacional de Pesquisas Espaciais). Four sets of 14 filters are placed in the
ambient environment, just above the dewar window but directly in line with the
detectors, leading to a mosaic having ~10mm gaps between each CCD. The massive
500mm aperture shutter is expected to be supplied by the Argelander-Institut
fur Astronomie, Bonn. We will present an overview of JPCam, from the filter
configuration through to the CCD mosaic camera. A brief outline of the main
J-PAS science projects will be included.Comment: 11 pages and 9 figure
Frontier Fields : Combining HST, VLT and Spitzer data to explore the 8 Universe behind the lensing cluster MACS04162403
(Abridged) The HST Frontier Fields project started at the end of 2013 with
the aim of providing extremely deep images of 6 massive galaxy clusters. One of
the main goals of this program is to push several telescopes to their limits in
order to provide the best current view of the earliest stages of the Universe.
We present a detailed analysis of 8 objects behind the HFFs lensing
cluster, MACS0416-2403, combining 0.3-1.6 m imaging from HST, ground-based
imaging from VLT HAWK-I, and 3.6 m and 4.5 m Spitzer Space
Telescope. We apply the classical Lyman Break technique, combining
non-detection criteria and color-selection. In order to avoid contamination by
mid- interlopers, we require a strong break between optical and near
infrared data. The luminosity function at 8 is computed using a MC
method taking advantage of the SED-fitting results. A piece of cautionary
information is gleaned from new deep optical photometry of a previously
identified 8 galaxy in this cluster, which is now firmly detected as a
mid- interloper with a strong mag Balmer break (between F606W
and F125W). Using the SED of this interloper, we estimate the contamination
rate of our MACS04162403 sample, as well as for previous samples in Abell
2744 based on HFF data. Our selection recovers 4 robust objects with
m ranging from 26.0 to 27.9 AB and located in modest amplification
regions (2.4). Two of the objects display a secondary break between the
IRAC 3.6 m and 4.5 m bands which could be associated to the Balmer
break or emission lines at 8. The candidates generally have star
formation rates around 10 M/yr and sizes ranging from 0.2 to
0.5 kpc, in good agreement with previous observations and expectations for
objects in the early Universe.Comment: 11 pages, 8 figures, accepted for publication in A&
GYES, a multifibre spectrograph for the CFHT
We have chosen the name of GYES, one of the mythological giants with one
hundred arms, offspring of Gaia and Uranus, for our instrument study of a
multifibre spectrograph for the prime focus of the Canada-France-Hawaii
Telescope. Such an instrument could provide an excellent ground-based
complement for the Gaia mission and a northern complement to the HERMES project
on the AAT. The CFHT is well known for providing a stable prime focus
environment, with a large field of view, which has hosted several imaging
instruments, but has never hosted a multifibre spectrograph. Building upon the
experience gained at GEPI with FLAMES-Giraffe and X-Shooter, we are
investigating the feasibility of a high multiplex spectrograph (about 500
fibres) over a field of view 1 degree in diameter. We are investigating an
instrument with resolution in the range 15000 to 30000, which should provide
accurate chemical abundances for stars down to 16th magnitude and radial
velocities, accurate to 1 km/s for fainter stars. The study is led by
GEPI-Observatoire de Paris with a contribution from Oxford for the study of the
positioner. The financing for the study comes from INSU CSAA and Observatoire
de Paris. The conceptual study will be delivered to CFHT for review by October
1st 2010.Comment: Contributed talk at the Gaia ELSA conference 2010, S\`evres 7-11 June
2010, to be published on the EAS Series, Editors: C. Turon, F. Arenou & F.
Meynadie
臨床応用の可能なマウス型モノクローナル抗体の作製 - 早期癌診断へのモノクローナル抗体2H6の応用 -
Here we present a facile synthetic method yielding a linear form of polydopamine via Kumada-coupling, which can be converted into water-soluble melanin, generating high contrast in photoacoustic imaging
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