271,980 research outputs found
Commitment and Dispatch of Heat and Power Units via Affinely Adjustable Robust Optimization
The joint management of heat and power systems is believed to be key to the
integration of renewables into energy systems with a large penetration of
district heating. Determining the day-ahead unit commitment and production
schedules for these systems is an optimization problem subject to uncertainty
stemming from the unpredictability of demand and prices for heat and
electricity. Furthermore, owing to the dynamic features of production and heat
storage units as well as to the length and granularity of the optimization
horizon (e.g., one whole day with hourly resolution), this problem is in
essence a multi-stage one. We propose a formulation based on robust
optimization where recourse decisions are approximated as linear or
piecewise-linear functions of the uncertain parameters. This approach allows
for a rigorous modeling of the uncertainty in multi-stage decision-making
without compromising computational tractability. We perform an extensive
numerical study based on data from the Copenhagen area in Denmark, which
highlights important features of the proposed model. Firstly, we illustrate
commitment and dispatch choices that increase conservativeness in the robust
optimization approach. Secondly, we appraise the gain obtained by switching
from linear to piecewise-linear decision rules within robust optimization.
Furthermore, we give directions for selecting the parameters defining the
uncertainty set (size, budget) and assess the resulting trade-off between
average profit and conservativeness of the solution. Finally, we perform a
thorough comparison with competing models based on deterministic optimization
and stochastic programming.Comment: 31 page
Web-Based Visualization of Very Large Scientific Astronomy Imagery
Visualizing and navigating through large astronomy images from a remote
location with current astronomy display tools can be a frustrating experience
in terms of speed and ergonomics, especially on mobile devices. In this paper,
we present a high performance, versatile and robust client-server system for
remote visualization and analysis of extremely large scientific images.
Applications of this work include survey image quality control, interactive
data query and exploration, citizen science, as well as public outreach. The
proposed software is entirely open source and is designed to be generic and
applicable to a variety of datasets. It provides access to floating point data
at terabyte scales, with the ability to precisely adjust image settings in
real-time. The proposed clients are light-weight, platform-independent web
applications built on standard HTML5 web technologies and compatible with both
touch and mouse-based devices. We put the system to the test and assess the
performance of the system and show that a single server can comfortably handle
more than a hundred simultaneous users accessing full precision 32 bit
astronomy data.Comment: Published in Astronomy & Computing. IIPImage server available from
http://iipimage.sourceforge.net . Visiomatic code and demos available from
http://www.visiomatic.org
Diagnostics Examples from Third-Generation Light Sources
This lesson discusses many examples of how the signals from the beam monitors
are used to diagnose the beam in circular, third-generation synchrotron light
sources. During the school, diagnostic examples in other machines (e.g.
colliders, CTF3, linacs and free-electron lasers (FEL), and medical
accelerators) were given in other lectures. This lesson assumes that the signal
generation in the instrument itself is already known; the main focus lies on
the dependence of the signals on various machine parameters and their
interpretation to diagnose the machine parameters and conditions.Comment: 22 pages, contribution to the CAS - CERN Accelerator School: Beam
Instrumentation, 2-15 June 2018, Tuusula, Finlan
On evolution of CMOS image sensors
CMOS Image Sensors have become the principal technology in majority of digital cameras. They started replacing the film and Charge Coupled Devices in the last decade with the promise of lower cost, lower power requirement, higher integration and the potential of focal plane processing. However, the principal factor behind their success has been the ability to utilise the shrinkage in CMOS technology to make smaller pixels, and thereby have more resolution without increasing the cost. With the market of image sensors exploding courtesy their inte- gration with communication and computation devices, technology developers improved the CMOS processes to have better optical performance. Nevertheless, the promises of focal plane processing as well as on-chip integration have not been fulfilled. The market is still being pushed by the desire of having higher number of pixels and better image quality, however, differentiation is being difficult for any image sensor manufacturer. In the paper, we will explore potential disruptive growth directions for CMOS Image sensors and ways to achieve the same
TARGET: toward a solution for the readout electronics of the Cherenkov Telescope Array
TARGET is an application specific integrated circuit (ASIC) designed to read
out signals recorded by the photosensors in cameras of very-high-energy
gamma-ray telescopes exploiting the imaging of Cherenkov radiation from
atmospheric showers. TARGET capabilities include sampling at a high rate
(typically 1 GSample/s), digitization, and triggering on the sum of four
adjacent pixels. The small size, large number of channels read out per ASIC
(16), low cost per channel, and deep buffer for trigger latency (~16 s at
1 GSample/s) make TARGET ideally suited for the readout in systems with a large
number of telescopes instrumented with compact photosensors like multi-anode or
silicon photomultipliers combined with dual-mirror optics. The possible
advantages of such systems are better sensitivity, a larger field of view, and
improved angular resolution. The two latest generations of TARGET ASICs, TARGET
5 and TARGET 7, are soon to be used for the first time in two prototypes of
small-sized and medium-sized dual-mirror telescopes proposed in the framework
of the Cherenkov Telescope Array (CTA) project. In this contribution we report
on the performance of the TARGET ASICs and discuss future developments.Comment: 8 pages, 3 figures. In Proceedings of the 34th International Cosmic
Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions
at arXiv:1508.0589
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