6,473 research outputs found
Learning Price-Elasticity of Smart Consumers in Power Distribution Systems
Demand Response is an emerging technology which will transform the power grid
of tomorrow. It is revolutionary, not only because it will enable peak load
shaving and will add resources to manage large distribution systems, but mainly
because it will tap into an almost unexplored and extremely powerful pool of
resources comprised of many small individual consumers on distribution grids.
However, to utilize these resources effectively, the methods used to engage
these resources must yield accurate and reliable control. A diversity of
methods have been proposed to engage these new resources. As opposed to direct
load control, many methods rely on consumers and/or loads responding to
exogenous signals, typically in the form of energy pricing, originating from
the utility or system operator. Here, we propose an open loop
communication-lite method for estimating the price elasticity of many customers
comprising a distribution system. We utilize a sparse linear regression method
that relies on operator-controlled, inhomogeneous minor price variations, which
will be fair to all the consumers. Our numerical experiments show that reliable
estimation of individual and thus aggregated instantaneous elasticities is
possible. We describe the limits of the reliable reconstruction as functions of
the three key parameters of the system: (i) ratio of the number of
communication slots (time units) per number of engaged consumers; (ii) level of
sparsity (in consumer response); and (iii) signal-to-noise ratio.Comment: 6 pages, 5 figures, IEEE SmartGridComm 201
The Burundi Heart Centre: From concept to design.
Burundi is one of the worlds poorest nations, which is also reflected in its relative lack of cardiac facilities, particularly those catering to young children and adults. The authors discuss current efforts to build The Burundi Heart Centre to help address this challenge. In particular, they highlight how the project can act as a case study for a sustainable architecture that involves local people and uses locally available materials in a contemporary and innovative way
Characterization of new hybrid pixel module concepts for the ATLAS Insertable B-Layer upgrade
The ATLAS Insertable B-Layer (IBL) collaboration plans to insert a fourth
pixel layer inside the present Pixel Detector to recover from eventual failures
in the current pixel system, especially the b-layer. Additionally the IBL will
ensure excellent tracking, vertexing and b-tagging performance during the LHC
phase I and add robustness in tracking with high luminosity pile-up. The
expected peak luminosity for IBL is 2 to 3centerdot1034 cm-2s-1 and IBL is
designed for an integrated luminosity of 700 fb-1. This corresponds to an
expected fluence of 5centerdot1015 1 MeV neqcm-2 and a total ionizing dose of
250 MRad. In order to cope with these requirements, two new module concepts are
under investigation, both based on a new front end IC, called FE-I4. This IC
was designed as readout chip for future ATLAS Pixel Detectors and its first
application will be the IBL. The planar pixel sensor (PPS) based module concept
benefits from its well understood design, which is kept as similar as possible
to the design of the current ATLAS Pixel Detector sensor. The second approach
of the new three dimensional (3D) silicon sensor technology benefits from the
shorter charge carrier drift distance to the electrodes, which completely
penetrate the sensor bulk. Prototype modules of both sensor concepts have been
build and tested in laboratory and test beam environment before and after
irradiation. Both concepts show very high performance even after irradiation to
5centerdot1015 1 MeV neqcm-2 and meet the IBL specifications in terms of hit
efficiency being larger than 97%. Lowest operational threshold studies have
been effected and prove independent of the used sensor concept the excellent
performance of FE-I4 based module concepts in terms of noise hit occupancy at
low thresholds.Comment: Part of 9th International Conference on Position Sensitive Detectors
(PSD9
Effect of Rotations and Shape Resonances on Photoassociation and Photoacceleration by Ultrashort Infrared Laser Pulses
A quantum dynamical description of an atomic collision pair interacting with the electric field of a short infrared laser pulse is developed. Inelastic processes in the electronic ground state are due to stimulated emission resulting in photoassociation, or absorption leading to photoacceleration. A perturbative approach based on a state space representation is compared with a numerical treatment using a grid representation in coordinate space. Special emphasis is on the role of rotations and, in particular, of shape resonances. It is shown that these quasibound states which are supported by the centrifugal barrier (for J> 0) can be used as initial states to effectively populate a selected bound state with specific vibrational and rotational quantum number (photoassociation), or a partial wave of a scattering state with defined energy and rotational quantum number (photoacceleration). Simulations are carried out for the prototype H + Cl collision pair. Also the effect of averaging over initial conditions (velocity, angular momenta) is investigated for a supersonic beam experiment. For a narrow velocity distribution, we predict the presence of a resonance structure of the association and acceleration probability as a function of the mean collision energy
Designing a Robust, Reliable and Repeatable Fieldwork Protocol for Hospital Observations
When undertaking fieldwork in a complex/sensitive environment such as a busy hospital ward, it is vital that the recording technique is robust (to cater for various eventualities), reliable (to accurately capture data) and repeatable (to share the data). It is therefore important to test and prepare protocols to maximize the effectiveness of the time available for any observations. Our poster demonstrates a real-time simulation built using the Unreal Engine 3D game platform and applied to our ‘Paths of Resistant Pathogens’ research study. This project aims to tackle issues of antimicrobial resistance (AMR) - such as superbugs - through a detailed architecturally-informed analysis of transmission risks inherent in hospital design. The simulation provides a number of benefits to assist with piloting optimal methodologies and protocols including: 1. Time-critical trialing of protocols 2. Assessing the accuracy of protocols 3. Training observer
Modelling the Northeast Atlantic circulation : implications for the spring invasion of shelf regions by Calanus finmarchicus
The appearance in spring of the copepod Calanus finmarchicus in continental shelf waters of the northeastern Atlantic has been hypothesized to be mainly attributable to invasion from across the continental slope rather than in situ overwintering. This paper describes the application of a hydrodynamic circulation model and a particle-tracking model to Northeast Atlantic waters in order to assess the influence of the flow field and ascent migration parameters on the spring invasion of C. finmarchicus. For hydrodynamic modelling, the Hamburg Shelf-Ocean Model (HAMSOM) was applied to the North Atlantic and Nordic Seas and forced with daily mean atmospheric data. Simulated flow fields from HAMSOM serve as forcing functions for a particle-tracking model of the same region. The robustness of the simulated shelf invasion in three target boxes of the Northeast Atlantic Shelf was assessed by means of a sensitivity analysis with respect to variations in four key migration parameters: overwintering depth, ascent rate, ascent timing, and depth during residence in upper layers. The invasion of the northern North Sea and Norwegian Shelf waters is more sensitive to ascent migration parameters than invasion of the Faroese Shelf. The main reason for enhanced sensitivity of the North Sea invasion is the time and space-dependent flow structure in the Faroe-Shetland Channel. Dense aggregations of overwintering C. finmarchicus are found in the Channel, but because of the complex flow field only a proportion of the overwintering stock has the capacity to reach the North Sea
Elaboration and TEM structural study of interfaces in composites produced by precipitation
Model ceramic matrix composites have been manufactured in a wide range of materials using the precipitation of a metal (Cu, Ni, Cr) in a ceramic matrix (nitride AIN or oxides MgO, Al2O3) providing, in each case low energy configurations at the heterophase interfaces. In connection to microelectronic applications, copper metallic particles precipitate in AIN after implantation by copper ions and anneal of the ceramic matrix. Faceted particles are imaged by HRTEM and are associated to a low energy structural and chemical configuration. Internal reduction experiments have been carried out on (Mg,Ni)O, (Mg,Cu)O and (Al,Cr)2O3 mixed oxides; the morphology, chemical composition and orientation relationship of the different precipitates are obtained through TEM observations and discussed in terms of interfacial energy and precipitate growth mechanism and kinetics. Conventional and high resolution TEM in conjonction to structural models have allowed a comprehensive description of the interface
Psychologische Prädiktoren für das Auftreten einer Major Depression und einer PTBS nach schweren Unfällen
Theoretischer Hintergrund/Fragestellung: Ziel unserer prospektiven Studie war die Identifikation von Prädiktoren für das Auftreten einer Depression im ersten halben Jahr nach einem Unfall.
Methode: Es wurden 52 Unfallpatienten untersucht. Die Ersterhebung erfolgte innerhalb der ersten sechs Wochen nach dem Unfall.
Ergebnisse: Depressive Patienten gaben kurz nach dem Unfall eine geringere Lebenszufriedenheit und soziale Unterstützung an und berichteten häufiger über psychische Störungen und traumatische Erlebnisse vor dem Unfall als Nicht-Depressive. Außerdem litten sie zum Zeitpunkt der Ersterhebung häufiger unter psychischen Störungen und fühlten sich durch die psychischen Symptome stärker beeinträchtigt.
Schlussfolgerung: Die Ergebnisse legen nahe, dass Patienten mit einem Risiko für die Entwicklung einer Depression bereits kurz nach einem Unfall identifiziert werden können
Climate fluctuations and the spring invasion of the North Sea by Calanus finmarchicus
The population of Calanus finmarchicus in the North Sea is replenished each spring by invasion from an overwintering stock located beyond the shelf edge. A combincation of field observations, statistical analysis of Continuous Plankton Recorder (CPR) data, and particle tracking model simulations, was used to investigate the processes involved in the cross-shelf invasion. The results showed that the main source of overwintering animals entering the North Sea in the spring is at depths of greater than 600m in the Faroe Shetland Channel, where concentrations of up to 620m -3 are found in association with the overflow of Norwegian Sea Deep Water (NSDW) across the Iceland Scotland Ridge. The input of this water mass to the Faroe Shetland Channel, and hence the supply of overwintering C. finmarchicus, has declined since the late 1960s due to changes in convective processes in the Greenland Sea. Beginning in February, animals start to emerge from the overwintering state and migrate to the surface waters, where their transport into the North Sea is mainly determined by the incidence of north-westerly winds that have declined since the 1960s. Together, these two factors explain a high proportion of the 30-year trends in spring abundance in the North Sea as measured by the CPR survey. Both the regional winds and the NSDW overflow are connected to the North Atlantic Oscillation Index (NAO), which is an atmospheric climate index, but with different time scales of response. Thus, interannual fluctuations in the NAO can cause immediate changes in the incidence of north-westerly winds without leading to corresponding changes in C. finmarchicus abundance in the North Sea, because the NSDW overflow responds over longer (decadal) time scales
Photoassociation of cold atoms with chirped laser pulses: time-dependent calculations and analysis of the adiabatic transfer within a two-state model
This theoretical paper presents numerical calculations for photoassociation
of ultracold cesium atoms with a chirped laser pulse and detailed analysis of
the results. In contrast with earlier work, the initial state is represented by
a stationary continuum wavefunction. In the chosen example, it is shown that an
important population transfer is achieved to vibrational levels in
the vicinity of the v=98 bound level in the external well of the
potential. Such levels lie in the energy range swept by
the instantaneous frequency of the pulse, thus defining a ``photoassociation
window''. Levels outside this window may be significantly excited during the
pulse, but no population remains there after the pulse. Finally, the population
transfer to the last vibrational levels of the ground (6s + 6s)
is significant, making stable molecules. The results are interpreted in the
framework of a two state model as an adiabatic inversion mechanism, efficient
only within the photoassociation window. The large value found for the
photoassociation rate suggests promising applications. The present chirp has
been designed in view of creating a vibrational wavepacket in the excited state
which is focussing at the barrier of the double well potential.Comment: 49 pages, 9 figures, submitted to Phys. Rev.
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