2,065 research outputs found
Broadcast Strategies with Probabilistic Delivery Guarantee in Multi-Channel Multi-Interface Wireless Mesh Networks
Multi-channel multi-interface Wireless Mesh Networks permit to spread the
load across orthogonal channels to improve network capacity. Although broadcast
is vital for many layer-3 protocols, proposals for taking advantage of multiple
channels mostly focus on unicast transmissions. In this paper, we propose
broadcast algorithms that fit any channel and interface assignment strategy.
They guarantee that a broadcast packet is delivered with a minimum probability
to all neighbors. Our simulations show that the proposed algorithms efficiently
limit the overhead
How coordination trajectories influence the performance of interorganizational project networks
This study examines how the joint use of integrators and contracts either enables or hampers coordination and, in turn, the performance of interorganizational project networks. Using extensive qualitative analyses and socio-metric techniques, we investigated coordination among organizations during seven small and medium-sized building projects. Our longitudinal study reveals how integrators develop connecting functions that, together with contracts' steering functions, largely drive coordination dynamics. Further data analyses provide insight into how coordination hinges on the prevalence of connecting or steering, which may more or less fit with coordination needs in various project phases. Given these findings, we theorize the contingent nature of the interplay between the use of integrators and contracts throughout projects. Our findings are integrated into a process model of how coordination trajectories lead to different performance levels of interorganizational project networks. Our study has theoretical implications for the literature on project-based organizing and, more broadly, the literature on interorganizational coordination. (17) How Coordination Trajectories Influence the Performance of Interorganizational Project Networks. Available from: https://www.researchgate.net/publication/316692856_How_Coordination_Trajectories_Influence_the_Performance_of_Interorganizational_Project_Networks [accessed Sep 27, 2017]
Reinvigorating the study of opportunism in supply chain management
Opportunism is a core issue in supply chain management. However, assumptionâomitted testing and a focus on general opportunism as opposed to specific forms of opportunism have stubbornly limited our understanding of this construct. Grounded in a review of empirical studies of opportunism, we identify empirical challenges that perpetuate conceptual limitations in the study of opportunism in supply chains. Hence, we provide suggestions about research designs and data sources that support an agenda that steers research to refine and develop the theory about opportunism. Our call for a reinvigoration of the study of opportunism supports rigor â by discussing research design and data sources â and relevance â by identifying topics for future supply chain research
Development of Partial Least Square models for the prediction of the concentration of a gustative stimulus in water from physiological data
International audienceClassical physicochemical or sensory methodologies are often inadequate to describe the perception of water and their correlation is complicated. Indeed, the taste of water is difficult to describe due to low concentrations of sapid molecules. The aim of this work was to combine sensory and physiological measurements in order to correlate data with chemical properties of sapid solutions
Prime Focus Spectrograph - Subaru's future -
The Prime Focus Spectrograph (PFS) of the Subaru Measurement of Images and
Redshifts (SuMIRe) project has been endorsed by Japanese community as one of
the main future instruments of the Subaru 8.2-meter telescope at Mauna Kea,
Hawaii. This optical/near-infrared multi-fiber spectrograph targets cosmology
with galaxy surveys, Galactic archaeology, and studies of galaxy/AGN evolution.
Taking advantage of Subaru's wide field of view, which is further extended with
the recently completed Wide Field Corrector, PFS will enable us to carry out
multi-fiber spectroscopy of 2400 targets within 1.3 degree diameter. A
microlens is attached at each fiber entrance for F-ratio transformation into a
larger one so that difficulties of spectrograph design are eased. Fibers are
accurately placed onto target positions by positioners, each of which consists
of two stages of piezo-electric rotary motors, through iterations by using
back-illuminated fiber position measurements with a wide-field metrology
camera. Fibers then carry light to a set of four identical fast-Schmidt
spectrographs with three color arms each: the wavelength ranges from 0.38
{\mu}m to 1.3 {\mu}m will be simultaneously observed with an average resolving
power of 3000. Before and during the era of extremely large telescopes, PFS
will provide the unique capability of obtaining spectra of 2400
cosmological/astrophysical targets simultaneously with an 8-10 meter class
telescope. The PFS collaboration, led by IPMU, consists of USP/LNA in Brazil,
Caltech/JPL, Princeton, & JHU in USA, LAM in France, ASIAA in Taiwan, and
NAOJ/Subaru.Comment: 13 pages, 11 figures, submitted to "Ground-based and Airborne
Instrumentation for Astronomy IV, Ian S. McLean, Suzanne K. Ramsay, Hideki
Takami, Editors, Proc. SPIE 8446 (2012)
Fiber Optical Cable and Connector System (FOCCoS) for PFS/Subaru
FOCCoS, Fiber Optical Cable and Connector System, has the main function of
capturing the direct light from the focal plane of Subaru Telescope using
optical fibers, each one with a microlens in its tip, and conducting this light
through a route containing connectors to a set of four spectrographs. The
optical fiber cable is divided in 3 different segments called Cable A, Cable B
and Cable C. Multi-fibers connectors assure precise connection among all
optical fibers of the segments, providing flexibility for instrument changes.
To assure strong and accurate connection, these sets are arranged inside two
types of assemblies: the Tower Connector, for connection between Cable C and
Cable B; and the Gang Connector, for connection between Cable B and Cable A.
Throughput tests were made to evaluate the efficiency of the connections. A
lifetime test connection is in progress. Cable C is installed inside the PFI,
Prime Focus Instrument, where each fiber tip with a microlens is bonded to the
end of the shaft of a 2-stage piezo-electric rotatory motor positioner; this
assembly allows each fiber to be placed anywhere within its patrol region,
which is 9.5mm diameter.. Each positioner uses a fiber arm to support the
ferrule, the microlens, and the optical fiber. 2400 of these assemblies are
arranged on a motor bench plate in a hexagonal-closed-packed disposition.Comment: 11 pages, 20 figure
Prime Focus Spectrograph (PFS) for the Subaru Telescope: Overview, recent progress, and future perspectives
PFS (Prime Focus Spectrograph), a next generation facility instrument on the
8.2-meter Subaru Telescope, is a very wide-field, massively multiplexed,
optical and near-infrared spectrograph. Exploiting the Subaru prime focus, 2394
reconfigurable fibers will be distributed over the 1.3 deg field of view. The
spectrograph has been designed with 3 arms of blue, red, and near-infrared
cameras to simultaneously observe spectra from 380nm to 1260nm in one exposure
at a resolution of ~1.6-2.7A. An international collaboration is developing this
instrument under the initiative of Kavli IPMU. The project is now going into
the construction phase aiming at undertaking system integration in 2017-2018
and subsequently carrying out engineering operations in 2018-2019. This article
gives an overview of the instrument, current project status and future paths
forward.Comment: 17 pages, 10 figures. Proceeding of SPIE Astronomical Telescopes and
Instrumentation 201
A New High-Throughput Tool to Screen Mosquito-Borne Viruses in Zika Virus Endemic/Epidemic Areas
International audienceMosquitoes are vectors of arboviruses affecting animal and human health. Arboviruses circulate primarily within an enzootic cycle and recurrent spillovers contribute to the emergence of human-adapted viruses able to initiate an urban cycle involving anthropophilic mosquitoes. The increasing volume of travel and trade offers multiple opportunities for arbovirus introduction in new regions. This scenario has been exemplified recently with the Zika pandemic. To incriminate a mosquito as vector of a pathogen, several criteria are required such as the detection of natural infections in mosquitoes. In this study, we used a high-throughput chip based on the BioMarkâą Dynamic arrays system capable of detecting 64 arboviruses in a single experiment. A total of 17,958 mosquitoes collected in Zika-endemic/epidemic countries (Brazil, French Guiana, Guadeloupe, Suriname, Senegal, and Cambodia) were analyzed. Here we show that this new tool can detect endemic and epidemic viruses in different mosquito species in an epidemic context. Thus, this fast and low-cost method can be suggested as a novel epidemiological surveillance tool to identify circulating arboviruses
Performance of a Large-Area GEM Detector Prototype for the Upgrade of the CMS Muon Endcap System
Gas Electron Multiplier (GEM) technology is being considered for the forward
muon upgrade of the CMS experiment in Phase 2 of the CERN LHC. Its first
implementation is planned for the GE1/1 system in the region of the muon endcap mainly to control muon level-1 trigger rates
after the second long LHC shutdown. A GE1/1 triple-GEM detector is read out by
3,072 radial strips with 455 rad pitch arranged in eight -sectors.
We assembled a full-size GE1/1 prototype of 1m length at Florida Tech and
tested it in 20-120 GeV hadron beams at Fermilab using Ar/CO 70:30 and
the RD51 scalable readout system. Four small GEM detectors with 2-D readout and
an average measured azimuthal resolution of 36 rad provided precise
reference tracks. Construction of this largest GEM detector built to-date is
described. Strip cluster parameters, detection efficiency, and spatial
resolution are studied with position and high voltage scans. The plateau
detection efficiency is [97.1 0.2 (stat)]\%. The azimuthal resolution is
found to be [123.5 1.6 (stat)] rad when operating in the center of
the efficiency plateau and using full pulse height information. The resolution
can be slightly improved by 10 rad when correcting for the bias due
to discrete readout strips. The CMS upgrade design calls for readout
electronics with binary hit output. When strip clusters are formed
correspondingly without charge-weighting and with fixed hit thresholds, a
position resolution of [136.8 2.5 stat] rad is measured, consistent
with the expected resolution of strip-pitch/ = 131.3 rad. Other
-sectors of the detector show similar response and performance.Comment: 8 pages, 32 figures, submitted to Proc. 2014 IEEE Nucl. Sci.
Symposium, Seattle, WA, reference adde
Quality control and beam test of GEM detectors for future upgrades of the CMS muon high rate region at the LHC
Gas Electron Multipliers (GEM) are a proven position sensitive gas detector technology which nowadays is becoming more widely used in High Energy Physics. GEMs offer an excellent spatial resolution and a high particle rate capability, with a close to 100% detection efficiency. In view of the high luminosity phase of the CERN Large Hadron Collider, these aforementioned features make GEMs suitable candidates for the future upgrades of the Compact Muon Solenoid (CMS) detector. In particular, the CMS GEM Collaboration proposes to cover the high-eta region of the muon system with large-area triple-GEM detectors, which have the ability to provide robust and redundant tracking and triggering functions. In this contribution, after a general introduction and overview of the project, the construction of full-size trapezoidal triple-GEM prototypes will be described in more detail. The procedures for the quality control of the GEM foils, including gain uniformity measurements with an x-ray source will be presented. In the past few years, several CMS triple-GEM prototype detectors were operated with test beams at the CERN SPS. The results of these test beam campaigns will be summarised
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