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Sample records for learning lisa torrey1

  1. Rightsizing LISA

    International Nuclear Information System (INIS)

    Stebbins, R T

    2009-01-01

    The Laser Interferometer Space Antenna (LISA) science requirements and conceptual design have been fairly stable for over a decade. In the interest of reducing costs, the LISA Project at NASA has looked for simplifications of the architecture, at downsizing of subsystems and at descopes of the entire mission. This is a natural activity of the formulation phase and one that is particularly timely in the current NASA budgetary context. There is, and will continue to be, enormous pressure for cost reduction from both ESA and NASA, reviewers and the broader research community. Here, the rationale for the baseline architecture is reviewed, and recent efforts to find simplifications and other reductions that might lead to savings are reported. A few possible simplifications have been found in the LISA baseline architecture. In the interest of exploring cost sensitivity, one moderate and one aggressive descope have been evaluated; the cost savings are modest and the loss of science is not.

  2. The LISA Pathfinder Mission

    International Nuclear Information System (INIS)

    Armano, M; Audley, H; Born, M; Danzmann, K; Diepholz, I; Auger, G; Binetruy, P; Baird, J; Bortoluzzi, D; Brandt, N; Fitzsimons, E; Bursi, A; Caleno, M; Cavalleri, A; Cesarini, A; Dolesi, R; Ferroni, V; Cruise, M; Dunbar, N; Ferraioli, L

    2015-01-01

    LISA Pathfinder (LPF), the second of the European Space Agency's Small Missions for Advanced Research in Technology (SMART), is a dedicated technology validation mission for future spaceborne gravitational wave detectors, such as the proposed eLISA mission. LISA Pathfinder, and its scientific payload - the LISA Technology Package - will test, in flight, the critical technologies required for low frequency gravitational wave detection: it will put two test masses in a near-perfect gravitational free-fall and control and measure their motion with unprecedented accuracy. This is achieved through technology comprising inertial sensors, high precision laser metrology, drag-free control and an ultra-precise micro-Newton propulsion system. LISA Pathfinder is due to be launched in mid-2015, with first results on the performance of the system being available 6 months thereafter.The paper introduces the LISA Pathfinder mission, followed by an explanation of the physical principles of measurement concept and associated hardware. We then provide a detailed discussion of the LISA Technology Package, including both the inertial sensor and interferometric readout. As we approach the launch of the LISA Pathfinder, the focus of the development is shifting towards the science operations and data analysis - this is described in the final section of the paper (paper)

  3. LISA system design highlights

    Energy Technology Data Exchange (ETDEWEB)

    Sallusti, M [European Space Agency, ESTEC, Keplerlaan 1, 2200 AG Noordwijk ZH (Netherlands); Gath, P; Weise, D; Berger, M; Schulte, H R, E-mail: marcello.sallusti@esa.in, E-mail: peter.gath@astrium.eads.ne, E-mail: dennis.weise@astrium.eads.ne, E-mail: marcel.berger@astrium.eads.ne, E-mail: Hans.Reiner.Schulte@astrium.eads.ne [Astrium GmbH Satellites, Claude-Dornier-Str., 88039 Friedrichshafen (Germany)

    2009-05-07

    A contract, started in January 2005, was awarded to a consortium of Astrium GmbH and Astrium Ltd for the LISA Mission Formulation. The scope of the contract was the development of a reference design for the mission architecture and for the mission elements (with particular focus on the payload) and a successive phase of derivation of requirements, to be concluded with a mission design review. The technical starting point was the output of the previous LISA study formalized in the Final Technical Report, issued in the year 2000. During the design phase, different architecture concepts were identified and traded off, including the LISA orbits, the measurement scheme and the opto-mechanical architecture. During the Mission Design Review (July 2008) the consolidated mission baseline design, and the specifications of the flight elements and of the payload subsystem and major components were presented. This paper gives a brief overview of the major design points of the latest design of the LISA system.

  4. LISA system design highlights

    International Nuclear Information System (INIS)

    Sallusti, M; Gath, P; Weise, D; Berger, M; Schulte, H R

    2009-01-01

    A contract, started in January 2005, was awarded to a consortium of Astrium GmbH and Astrium Ltd for the LISA Mission Formulation. The scope of the contract was the development of a reference design for the mission architecture and for the mission elements (with particular focus on the payload) and a successive phase of derivation of requirements, to be concluded with a mission design review. The technical starting point was the output of the previous LISA study formalized in the Final Technical Report, issued in the year 2000. During the design phase, different architecture concepts were identified and traded off, including the LISA orbits, the measurement scheme and the opto-mechanical architecture. During the Mission Design Review (July 2008) the consolidated mission baseline design, and the specifications of the flight elements and of the payload subsystem and major components were presented. This paper gives a brief overview of the major design points of the latest design of the LISA system.

  5. LISA Pathfinder and eLISA news

    Science.gov (United States)

    Thorpe, James Ira; Mueller, Guido

    2014-01-01

    Two important gatherings of the space-based gravitational-wave detector community were held in Zurich, Switzerland this past March. The first was a meeting of the Science Working Team for LISA Pathfinder (LPF), a dedicated technology demonstrator mission for a future LISA-like gravitational wave observatory. LPF is entering an extremely exciting phase with launch less than 15 months away. All flight components for both the European science payload, known as the LISA Technology Package (LTP), and the NASA science payload, known as the Space Technology 7 Disturbance Reduction System (ST7-DRS), have been delivered and are undergoing integration. The final flight component for the spacecraft bus, a cold-gas thruster based on the successful GAIA design, will be delivered later this year. Current focus is on completing integration of the science payload (see Figures 1 and 2) and preparation for operations and data analysis. After a launch in Summer 2015, LPF will take approximately 90 days to reach its operational orbit around the Earth-Sun Lagrange point (L1), where it will begin science operations. After 90 days of LTP operations followed by 90 days of DRS operations, LPF will have completed its prime mission of paving the way for a space-based observatory of gravitational waves in the milliHertz band. Immediately following the meeting of the LPF team, the eLISA consortium held its third progress meeting. The consortium (www.elisascience.org) is the organizing body of the European space-based gravitational-wave community, and it was responsible for the "The Gravitational Universe" whitepaper that resulted in the November 2013 election of a gravitational-wave science theme for ESA's Cosmic Visions L3 opportunity. In preparation for an L3 mission concept call, which is expected later this decade, and for launch in the mid 2030s, the eLISA consortium members are coordinating technology development and mission study activities which will build on the LPF results. The final

  6. LISA and asteroids

    International Nuclear Information System (INIS)

    Vinet, Jean-Yves

    2006-01-01

    LISA is a joint ESA-NASA mission aiming for cosmic gravitational wave detection and analysis. We address here the question of a special kind of signal caused by asteroid encounters. We present a short theory of the detection of such signals

  7. LISA and the LTP

    International Nuclear Information System (INIS)

    Jennrich, O.

    2002-01-01

    The primary objective of the LISA (Laser Interferometer Space Antenna mission is the detection and observation of gravitational waves from massive black holes (MBH) and galactic binaries in the frequency range 10 -4 Hz ... 10 -1 Hz. This low-frequency range is inaccessible to ground-based interferometers due to the background of local gravitational noise and because ground-based interferometers are limited in length to a few kilometres. LISA is envisaged as an ESA/NASA collaborative project, selected an ESA cornerstone mission and included in NASA's strategic plan and with a nominal launch date in 2011. SMART-2 is primarily intended to demonstrate the key technologies for the ESA/NASA collaborative LISA cornerstone mission. The synergy with the technology being used for Darwin motivates the utilization of SMART-2 for both missions. To this end, SMART-2 will accommodate a LISA technology package (LTP), provided by European institutes and industry and possibly also a Disturbance Reduction System (DRS) that is very similar to the LTP and has the same goals but is provided by US institutes and industry

  8. Synthetic LISA: Simulating time delay interferometry in a model LISA

    International Nuclear Information System (INIS)

    Vallisneri, Michele

    2005-01-01

    We report on three numerical experiments on the implementation of Time-Delay Interferometry (TDI) for LISA, performed with Synthetic LISA, a C++/Python package that we developed to simulate the LISA science process at the level of scientific and technical requirements. Specifically, we study the laser-noise residuals left by first-generation TDI when the LISA armlengths have a realistic time dependence; we characterize the armlength-measurement accuracies that are needed to have effective laser-noise cancellation in both first- and second-generation TDI; and we estimate the quantization and telemetry bitdepth needed for the phase measurements. Synthetic LISA generates synthetic time series of the LISA fundamental noises, as filtered through all the TDI observables; it also provides a streamlined module to compute the TDI responses to gravitational waves according to a full model of TDI, including the motion of the LISA array and the temporal and directional dependence of the armlengths. We discuss the theoretical model that underlies the simulation, its implementation, and its use in future investigations on system-characterization and data-analysis prototyping for LISA

  9. LISA Pathfinder: A Mission Status

    Science.gov (United States)

    Hewitson, Martin; LISA Pathfinder Team Team

    2016-03-01

    On December 3rd at 04:04 UTC, The European Space Agency launched the LISA Pathfinder satellite on board a VEGA rocket from Kourou in French Guiana. After a series of orbit raising manoeuvres and a 2 month long transfer orbit, LISA Pathfinder arrived at L1. Following a period of commissioning, the science operations commenced at the start of March, beginning the demonstration of technologies and methodologies which pave the way for a future large-scale gravitational wave observatory in space. This talk will present the scientific goals of the mission, discuss the technologies being tested, elucidate the link to a future space-based observatory, such as LISA, and present preliminary results from the in-orbit operations and experiments.

  10. Improving the sensitivity of LISA

    International Nuclear Information System (INIS)

    Nayak, K Rajesh; Pai, A; Dhurandhar, S V; Vinet, J-Y

    2003-01-01

    It has been shown in several recent papers that the six Doppler data streams obtained from a triangular LISA configuration can be combined by appropriately delaying the data streams for cancelling the laser frequency noise. Raw laser noise is several orders of magnitude above the other noises and thus it is essential to bring it down to the level of other noises such as shot, acceleration, etc. A rigorous and systematic formalism using the powerful techniques of computational commutative algebra was developed, which generates in principle all the data combinations cancelling the laser frequency noise. The relevant data combinations form a first module of syzygies. In this paper, we use this formalism to advantage for optimizing the sensitivity of LISA by analysing the noise and signal covariance matrices. The signal covariance matrix is calculated for binaries whose frequency changes at most adiabatically and the signal is averaged over polarizations and directions. We then present the extremal SNR curves for all the data combinations in the module. They correspond to the eigenvectors of the noise and signal covariance matrices. A LISA 'network' SNR is also computed by combining the outputs of the eigenvectors. We show that substantial gains in sensitivity can be obtained by employing these strategies. The maximum SNR curve can yield an improvement up to 70% over the Michelson, mainly at high frequencies, while the improvement using the network SNR ranges from 40% to over 100%. Finally, we describe a simple toy model, in which LISA rotates in a plane. In this analysis, we estimate the improvement in the LISA sensitivity, if one switches from one data combination to another as it rotates. Here the improvement in sensitivity, if one switches optimally over three cyclic data combinations of the eigenvector, is about 55% on average over the LISA bandwidth. The corresponding SNR improvement increases to 60%, if one maximizes over the module

  11. Molecular laser stabilization for LISA

    Science.gov (United States)

    Halloin, Hubert; Acef, Ouali; Argence, Berengere; Jeannin, Olivier; Prat, Pierre; de Vismes, Eden; Plagnol, Eric; Brillet, Alain; Mondin, Linda; Berthon, Jacques; Turazza, Oscar

    2017-11-01

    The expected performance of LISA relies on two main technical challenges: the ability for the spacecrafts to precisely follow the free-flying masses and the outstanding precision of the phase shift measurement. This latter constraint requires frequency stabilized lasers and efficient numerical algorithms to account for the redundant, delayed noise propagation, thus cancelling laser phase noise by many orders of magnitude (TDI methods). Recently involved in the technical developments for LISA, the goal of our team at APC (France) is to contribute on these two subjects: frequency reference for laser stabilization and benchtop simulation of the interferometer. In the present design of LISA, two stages of laser stabilization are used (not accounting for the "post-processed" TDI algorithm): laser pre-stabilization on a frequency reference and lock on the ultra stable distance between spacecrafts (arm-locking). While the foreseen (and deeply studied) laser reference consists of a Fabry-Perot cavity, other techniques may be suitable for LISA or future metrology missions. In particular, locking to a molecular reference (namely iodine in the case of the LISA Nd:YAG laser) is an interesting alternative. It offers the required performance with very good long-term stability (absolute frequency reference) though the reference can be slightly tuned to account for arm-locking. This technique is currently being investigated by our team and optimized for LISA (compactness, vacuum compatibility, ease of use and initialization, etc.). A collaboration with a French laboratory (the SYRTE) had been started aiming to study a second improved technique consisting in inserting the iodine cell in a Fabry-Perot cavity. Ongoing results and prospects to increase the performance of the system are presented in the present article.

  12. Laser modulator for LISA pathfinder

    Science.gov (United States)

    Voland, C.; Lund, G.; Coppoolse, W.; Crosby, P.; Stadler, M.; Kudielka, K.; Özkan, C.

    2017-11-01

    LISA Pathfinder is an ESA experiment to demonstrate the key technologies needed for the LISA mission to detect gravitational waves in space. The LISA Pathfinder spacecraft represents one arm of the LISA interferometer, containing an optical metrology system and two proof masses as inertial references for the drag-free control system. The LISA Pathfinder payload consists of two drag-free floating test masses located in the inertial sensors with their control electronics and an optical metrology subsystem. The optical metrology subsystem monitors the movement of both test masses relative to each other and to the spacecraft with very high sensitivity and resolution. This is achieved with a heterodyne Mach- Zehnder interferometer. This interferometer requires as input two coherent laser beams with a heterodyne frequency difference of a few kHz. To generate the two laser beams with a heterodyne frequency difference a Nd:YAG laser is used together with the Laser Modulator. The Nd:YAG laser generates a single coherent laser signal at a wavelength of 1064nm which is fibre coupled to the Laser Modulator. The Laser Modulator then generates the two optical beams with the required heterodyne frequency offset. In addition, the Laser Modulator is required to perform laser amplitude stabilization and optical path difference control for the two optical signals. The Laser Modulator consists of an optical unit - the LMU - and RF synthesiser, power amplification and control electronics. These electronics are all housed in the Laser Modulator Electronics (LME). The LMU has four primary functions: • Splitting of the input laser beam into two paths for later superposition in the interferometer. • Applying different frequency shifts to each of the beams. • Providing amplitude modulation control to each of the beams. • Providing active control of the optical path length difference between the two optical paths. The present paper describes the design and performance of the LMU

  13. Lisa Jevbratt / Lisa Jevbratt ; interv. Tilman Baumgärtel

    Index Scriptorium Estoniae

    Jevbratt, Lisa

    2006-01-01

    1967. a. Rootsis sündinud ja USA-s elavast kunstnikust Lisa Jevbrattist ning tema loomingust, 2000. a. jaanuaris tehtud meiliintervjuu kunstnikuga. L. Jevbratt kuulub rühmitusse C5, tema teosed keskenduvad pigem Interneti struktuurile kui selle sisule. Pikemalt võrguteosest "1:1" (2000), mille teemaks on IP-aadressid., lühidalt tööst "The Stillman Project" (1997), kunstniku galeriist "Non-Site"

  14. Micrometeorite Science with LISA Pathfinder

    Science.gov (United States)

    Pagane, Nicole; Thorpe, James Ira; Littenberg, Tyson; Littenberg, Tyson; Baker, John; Slutsky, Jacob; Hourihane, Sophie; LISA Pathfinder Team

    2018-01-01

    The primary objective of LISA Pathfinder (LPF) was to demonstrate drag-free control of test masses—along with the technology necessary to maintain the inertial motion—that LISA (Laser Interferometer Space Antenna) would later utilize as a space-based gravitational wave observatory. Due to the precise interferometry used during the mission, LPF could be employed as an accelerometer and used to detect micrometeorite impacts while in orbit about the Sun-Earth Lagrange Point L1. To infer micrometeorite impacts, the flight data was processed for event reconstruction to determine external acceleration of LPF; impact parameters were then estimated through a Markov-Chain Monte-Carlo (MCMC) tool via Bayesian analysis by fitting delta functions in the acceleration domain. As impact candidates were collected, a catalog of event data was curated with the reconstructed estimated parameters, among which were impact sky localizations that were later rotated into more intuitive reference frames. To infer the results of this dust modeling technique, current micrometeorite models were compared to the impact data. In the final reference frame common to the available micrometeorite models, the reconstructed impacts appear to cluster at (±90°, 0°)—where impacts prograde in this longitude-latitude frame were at (-90°, 0°), retrograde were (90°, 0°), and the sun was centered at the origin. The two available models used for comparison were of the Jupiter-family comets (JFC) and Halley-type comets (HTC), which clustered primarily around (±90°, 0°) and (0°, ±20°) respectively. This suggests that the JFC population seems to account for the majority of the impacts detected by LPF. The models’ expected rates given localization and velocity are currently being compared to the reconstructed data to further characterize the micrometeorite populations at L1. We will present our current analysis of this data set and discuss possibilities of extending such an analysis for LISA.

  15. LISA Pathfinder: OPD loop characterisation

    Science.gov (United States)

    Born, Michael; LPF Collaboration

    2017-05-01

    The optical metrology system (OMS) of the LISA Pathfinder mission is measuring the distance between two free-floating test masses with unprecedented precision. One of the four OMS heterodyne interferometers reads out the phase difference between the reference and the measurement laser beam. This phase from the reference interferometer is common to all other longitudinal interferometer read outs and therefore subtracted. In addition, the phase is fed back via the digital optical pathlength difference (OPD) control loop to keep it close to zero. Here, we analyse the loop parameters and compare them to on-ground measurement results.

  16. Observing a Gravitational Wave Background With Lisa

    National Research Council Canada - National Science Library

    Tinto, M; Armstrong, J; Estabrook, F

    2000-01-01

    ... formation of several observables. All are independent of lasers and frequency standard phase fluctuations, but have different couplings to gravitational waves and to the various LISA instrumental noises...

  17. Mona Lisa, lesbiahvid ja seksilaulud / Kaivo Kopli

    Index Scriptorium Estoniae

    Kopli, Kaivo

    2003-01-01

    Ameerika Teaduse Edendamise Assotsiatsiooni (AAA) konverentsil esitatud uusimatest teadusuuringutest. Artiklid: Mona Lisa naeratuse saladus paljastatud ; Lesbilised Jaapani makaagid seljatavad Darwini ; Linnud õpivad uusi laule uue partneri leidmiseks

  18. LISA Pathfinder instrument data analysis

    Science.gov (United States)

    Guzman, Felipe

    LISA Pathfinder (LPF) is an ESA-launched demonstration mission of key technologies required for the joint NASA-ESA gravitational wave observatory in space, LISA. As part of the LPF interferometry investigations, analytic models of noise sources and corresponding noise subtrac-tion techniques have been developed to correct for effects like the coupling of test mass jitter into displacement readout, and fluctuations of the laser frequency or optical pathlength difference. Ground testing of pre-flight hardware of the Optical Metrology Subsystem is currently ongoing at the Albert Einstein Institute Hannover. In collaboration with NASA Goddard Space Flight Center, the LPF mission data analysis tool LTPDA is being used to analyze the data product of these tests. Furthermore, the noise subtraction techniques and in-flight experiment runs for noise characterization are being defined as part of the mission experiment master plan. We will present the data analysis outcome of pre-flight hardware ground tests and possible noise subtraction strategies for in-flight instrument operations.

  19. Lisa Woodward | IDRC - International Development Research Centre

    International Development Research Centre (IDRC) Digital Library (Canada)

    Lisa Woodward is Special Advisor to the President. Before joining IDRC, Lisa held positions in strategic planning, performance measurement, evaluation, risk management, and policy development in federal organizations, including Fisheries and Oceans Canada, the Canadian International Development Agency, and the ...

  20. LISA: Probing the Universe with Gravitational Waves

    NARCIS (Netherlands)

    Prince, T.A.; Binetruy, P.; Centrella, J.; Finn, L.S.; Hogan, C.; Nelemans, G.A.; Phinney, E.S.; Schutz, B.; Team, L.I.S.

    2006-01-01

    LISA is a joint NASA/ESA space mission for detection and study of low-frequency gravitational waves in the band from 0.1 mHz to 0.1 Hz. The mission consists of three satellites separated by a nominal distance of 5 million kilometers, with precision metrology provided by laser ranging. LISA will

  1. Black Holes, Gravitational Waves, and LISA

    Science.gov (United States)

    Baker, John

    2009-01-01

    Binary black hole mergers are central to many key science objectives of the Laser Interferometer Space Antenna (LISA). For many systems the strongest part of the signal is only understood by numerical simulations. Gravitational wave emissions are understood by simulations of vacuum General Relativity (GR). I discuss numerical simulation results from the perspective of LISA's needs, with indications of work that remains to be done. Some exciting scientific opportunities associated with LISA observations would be greatly enhanced if prompt electromagnetic signature could be associated. I discuss simulations to explore this possibility. Numerical simulations are important now for clarifying LISA's science potential and planning the mission. We also consider how numerical simulations might be applied at the time of LISA's operation.

  2. Possible LISA Technology Applications for Other Missions

    Science.gov (United States)

    Livas, Jeffrey

    2018-01-01

    The Laser Interferometer Space Antenna (LISA) has been selected as the third large class mission launch opportunity of the Cosmic Visions Program by the European Space Agency (ESA). LISA science will explore a rich spectrum of astrophysical gravitational-wave sources expected at frequencies between 0.0001 and 0.1 Hz and complement the work of other observatories and missions, both space and ground-based, electromagnetic and non-electromagnetic. Similarly, LISA technology may find applications for other missions. This paper will describe the capabilities of some of the key technologies and discuss possible contributions to other missions.

  3. Lisa's Lemonade Stand: Exploring Algebraic Ideas.

    Science.gov (United States)

    Billings, Esther M. H.; Lakatos, Tracy

    2003-01-01

    Presents an activity, "Lisa's Lemonade Stand," that actively engages students in algebraic thinking as they analyze change by investigating relationships between variables and gain experience describing and representing these relationships graphically. (YDS)

  4. Optimizing the Earth-LISA 'rendezvous'

    International Nuclear Information System (INIS)

    De Marchi, Fabrizio; Pucacco, Giuseppe; Bassan, Massimo

    2012-01-01

    We present a general survey of heliocentric LISA orbits, hoping that it might help in the exercise of rescoping the mission. We try to semi-analytically optimize the orbital parameters in order to minimize the disturbances coming from the Earth-LISA interaction. In a set of numerical simulations, we include non-autonomous perturbations and provide an estimate of Doppler shift and breathing as a function of the trailing angle. (paper)

  5. Novel Payload Architectures for LISA

    Science.gov (United States)

    Johann, Ulrich A.; Gath, Peter F.; Holota, Wolfgang; Schulte, Hans Reiner; Weise, Dennis

    2006-11-01

    As part of the current LISA Mission Formulation Study, and based on prior internal investigations, Astrium Germany has defined and preliminary assessed novel payload architectures, potentially reducing overall complexity and improving budgets and costs. A promising concept is characterized by a single active inertial sensor attached to a single optical bench and serving both adjacent interferometer arms via two rigidly connected off-axis telescopes. The in-plane triangular constellation ``breathing angle'' compensation is accomplished by common telescope in-field of view pointing actuation of the transmit/received beams line of sight. A dedicated actuation mechanism located on the optical bench is required in addition to the on bench actuators for differential pointing of the transmit and receive direction perpendicular to the constellation plane. Both actuators operate in a sinusoidal yearly period. A technical challenge is the actuation mechanism pointing jitter and the monitoring and calibration of the laser phase walk which occurs while changing the optical path inside the optical assembly during re-pointing. Calibration or monitoring of instrument internal phase effects e.g. by a laser metrology truss derived from the existing interferometry is required. The architecture exploits in full the two-step interferometry (strap down) concept, separating functionally inter spacecraft and intra-spacecraft interferometry (reference mass laser metrology degrees of freedom sensing). The single test mass is maintained as cubic, but in free-fall in the lateral degrees of freedom within the constellation plane. Also the option of a completely free spherical test mass with full laser interferometer readout has been conceptually investigated. The spherical test mass would rotate slowly, and would be allowed to tumble. Imperfections in roundness and density would be calibrated from differential wave front sensing in a tetrahedral arrangement, supported by added attitude

  6. Confusion noise from LISA capture sources

    International Nuclear Information System (INIS)

    Barack, Leor; Cutler, Curt

    2004-01-01

    Captures of compact objects (COs) by massive black holes (MBHs) in galactic nuclei will be an important source for LISA, the proposed space-based gravitational wave (GW) detector. However, a large fraction of captures will not be individually resolvable - either because they are too distant, have unfavorable orientation, or have too many years to go before final plunge - and so will constitute a source of 'confusion noise', obscuring other types of sources. In this paper we estimate the shape and overall magnitude of the GW background energy spectrum generated by CO captures. This energy spectrum immediately translates to a spectral density S h capt (f) for the amplitude of capture-generated GWs registered by LISA. The overall magnitude of S h capt (f) is linear in the CO capture rates, which are rather uncertain; therefore we present results for a plausible range of rates. S h capt (f) includes the contributions from both resolvable and unresolvable captures, and thus represents an upper limit on the confusion noise level. We then estimate what fraction of S h capt (f) is due to unresolvable sources and hence constitutes confusion noise. We find that almost all of the contribution to S h capt (f) coming from white dwarf and neutron star captures, and at least ∼30% of the contribution from black hole captures, is from sources that cannot be individually resolved. Nevertheless, we show that the impact of capture confusion noise on the total LISA noise curve ranges from insignificant to modest, depending on the rates. Capture rates at the high end of estimated ranges would raise LISA's overall (effective) noise level [fS h eff (f)] 1/2 by at most a factor ∼2 in the frequency range 1-10 mHz, where LISA is most sensitive. While this slightly elevated noise level would somewhat decrease LISA's sensitivity to other classes of sources, we argue that, overall, this would be a pleasant problem for LISA to have: It would also imply that detection rates for CO captures

  7. Free-flight experiments in LISA Pathfinder

    International Nuclear Information System (INIS)

    Armano, M; Audley, H; Born, M; Danzmann, K; Diepholz, I; Auger, G; Binetruy, P; Baird, J; Bortoluzzi, D; Brandt, N; Bursi, A; Caleno, M; Cavalleri, A; Cesarini, A; Dolesi, R; Ferroni, V; Cruise, M; Cutler, C; Dunbar, N; Ferraioli, L

    2015-01-01

    The LISA Pathfinder mission will demonstrate the technology of drag-free test masses for use as inertial references in future space-based gravitational wave detectors. To accomplish this, the Pathfinder spacecraft will perform drag-free flight about a test mass while measuring the acceleration of this primary test mass relative to a second reference test mass. Because the reference test mass is contained within the same spacecraft, it is necessary to apply forces on it to maintain its position and attitude relative to the spacecraft. These forces are a potential source of acceleration noise in the LISA Pathfinder system that are not present in the full LISA configuration. While LISA Pathfinder has been designed to meet it's primary mission requirements in the presence of this noise, recent estimates suggest that the on-orbit performance may be limited by this ‘suspension noise’. The drift-mode or free-flight experiments provide an opportunity to mitigate this noise source and further characterize the underlying disturbances that are of interest to the designers of LISA-like instruments. This article provides a high-level overview of these experiments and the methods under development to analyze the resulting data. (paper)

  8. Data analysis for the LISA Technology Package

    International Nuclear Information System (INIS)

    Hewitson, M; Danzmann, K; Diepholz, I; GarcIa, A; Armano, M; Fauste, J; Benedetti, M; Bogenstahl, J; Bortoluzzi, D; Bosetti, P; Cristofolini, I; Brandt, N; Cavalleri, A; Ciani, G; Dolesi, R; Ferraioli, L; Cruise, M; Fertin, D; GarcIa, C; Fichter, W

    2009-01-01

    The LISA Technology Package (LTP) on board the LISA Pathfinder mission aims to demonstrate some key concepts for LISA which cannot be tested on ground. The mission consists of a series of preplanned experimental runs. The data analysis for each experiment must be designed in advance of the mission. During the mission, the analysis must be carried out promptly so that the results can be fed forward into subsequent experiments. As such a robust and flexible data analysis environment needs to be put in place. Since this software is used during mission operations and effects the mission timeline, it must be very robust and tested to a high degree. This paper presents the requirements, design and implementation of the data analysis environment (LTPDA) that will be used for analysing the data from LTP. The use of the analysis software to perform mock data challenges (MDC) is also discussed, and some highlights from the first MDC are presented.

  9. Data analysis for the LISA Technology Package

    Energy Technology Data Exchange (ETDEWEB)

    Hewitson, M; Danzmann, K; Diepholz, I; GarcIa, A [Albert-Einstein-Institut, Max-Planck-Institut fuer Gravitationsphysik und Universitaet Hannover, 30167 Hannover (Germany); Armano, M; Fauste, J [European Space Agency, ESAC, Villanueva de la Canada, 28692 Madrid (Spain); Benedetti, M [Dipartimento di Ingegneria dei Materiali e Tecnologie Industriali, Universita di Trento and INFN, Gruppo Collegato di Trento, Mesiano, Trento (Italy); Bogenstahl, J [Department of Physics and Astronomy, University of Glasgow, Glasgow (United Kingdom); Bortoluzzi, D; Bosetti, P; Cristofolini, I [Dipartimento di Ingegneria Meccanica e Strutturale, Universita di Trento and INFN, Gruppo Collegato di Trento, Mesiano, Trento (Italy); Brandt, N [Astrium GmbH, 88039 Friedrichshafen (Germany); Cavalleri, A; Ciani, G; Dolesi, R; Ferraioli, L [Dipartimento di Fisica, Universita di Trento and INFN, Gruppo Collegato di Trento, 38050 Povo, Trento (Italy); Cruise, M [Department of Physics and Astronomy, University of Birmingham, Birmingham (United Kingdom); Fertin, D; GarcIa, C [European Space Agency, ESTEC, 2200 AG Noordwijk (Netherlands); Fichter, W, E-mail: martin.hewitson@aei.mpg.d [Institut fuer Flugmechanik und Flugregelung, 70569 Stuttgart (Germany)

    2009-05-07

    The LISA Technology Package (LTP) on board the LISA Pathfinder mission aims to demonstrate some key concepts for LISA which cannot be tested on ground. The mission consists of a series of preplanned experimental runs. The data analysis for each experiment must be designed in advance of the mission. During the mission, the analysis must be carried out promptly so that the results can be fed forward into subsequent experiments. As such a robust and flexible data analysis environment needs to be put in place. Since this software is used during mission operations and effects the mission timeline, it must be very robust and tested to a high degree. This paper presents the requirements, design and implementation of the data analysis environment (LTPDA) that will be used for analysing the data from LTP. The use of the analysis software to perform mock data challenges (MDC) is also discussed, and some highlights from the first MDC are presented.

  10. Reconstructing the dark sector interaction with LISA

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Rong-Gen; Yang, Tao [CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, Beijing 100190 (China); Tamanini, Nicola, E-mail: cairg@itp.ac.cn, E-mail: nicola.tamanini@cea.fr, E-mail: yangtao@itp.ac.cn [Institut de Physique Théorique, CEA-Saclay, CNRS UMR 3681, Université Paris-Saclay, F-91191 Gif-sur-Yvette (France)

    2017-05-01

    We perform a forecast analysis of the ability of the LISA space-based interferometer to reconstruct the dark sector interaction using gravitational wave standard sirens at high redshift. We employ Gaussian process methods to reconstruct the distance-redshift relation in a model independent way. We adopt simulated catalogues of standard sirens given by merging massive black hole binaries visible by LISA, with an electromagnetic counterpart detectable by future telescopes. The catalogues are based on three different astrophysical scenarios for the evolution of massive black hole mergers based on the semi-analytic model of E. Barausse, Mon. Not. Roy. Astron. Soc. 423 (2012) 2533. We first use these standard siren datasets to assess the potential of LISA in reconstructing a possible interaction between vacuum dark energy and dark matter. Then we combine the LISA cosmological data with supernovae data simulated for the Dark Energy Survey. We consider two scenarios distinguished by the time duration of the LISA mission: 5 and 10 years. Using only LISA standard siren data, the dark sector interaction can be well reconstructed from redshift z ∼1 to z ∼3 (for a 5 years mission) and z ∼1 up to z ∼5 (for a 10 years mission), though the reconstruction is inefficient at lower redshift. When combined with the DES datasets, the interaction is well reconstructed in the whole redshift region from 0 z ∼ to z ∼3 (5 yr) and z ∼0 to z ∼5 (10 yr), respectively. Massive black hole binary standard sirens can thus be used to constrain the dark sector interaction at redshift ranges not reachable by usual supernovae datasets which probe only the z ∼< 1.5 range. Gravitational wave standard sirens will not only constitute a complementary and alternative way, with respect to familiar electromagnetic observations, to probe the cosmic expansion, but will also provide new tests to constrain possible deviations from the standard ΛCDM dynamics, especially at high redshift.

  11. LISA Mission and System architectures and performances

    International Nuclear Information System (INIS)

    Gath, Peter F; Weise, Dennis; Schulte, Hans-Reiner; Johann, Ulrich

    2009-01-01

    In the context of the LISA Mission Formulation Study, the LISA System was studied in detail and a new baseline architecture for the whole mission was established. This new baseline is the result of trade-offs on both, mission and system level. The paper gives an overview of the different mission scenarios and configurations that were studied in connection with their corresponding advantages and disadvantages as well as performance estimates. Differences in the required technologies and their influence on the overall performance budgets are highlighted for all configurations. For the selected baseline concept, a more detailed description of the configuration is given and open issues in the technologies involved are discussed.

  12. LISA Mission and System architectures and performances

    Energy Technology Data Exchange (ETDEWEB)

    Gath, Peter F; Weise, Dennis; Schulte, Hans-Reiner; Johann, Ulrich, E-mail: peter.gath@astrium.eads.ne [Astrium GmbH Satellites, 88039 Friedrichshafen (Germany)

    2009-03-01

    In the context of the LISA Mission Formulation Study, the LISA System was studied in detail and a new baseline architecture for the whole mission was established. This new baseline is the result of trade-offs on both, mission and system level. The paper gives an overview of the different mission scenarios and configurations that were studied in connection with their corresponding advantages and disadvantages as well as performance estimates. Differences in the required technologies and their influence on the overall performance budgets are highlighted for all configurations. For the selected baseline concept, a more detailed description of the configuration is given and open issues in the technologies involved are discussed.

  13. Galactic binaries with eLISA

    OpenAIRE

    Nelemans, G.

    2013-01-01

    I review what eLISA will see from Galactic binaries -- double stars with orbital periods less than a few hours and white dwarf (or neutron star/black hole) components. I discuss the currently known binaries that are guaranteed (or verification) sources and explain why the expected total number of eLISA Galactic binaries is several thousand, even though there are large uncertainties in our knowledge of this population, in particular that of the interacting AM CVn systems. I very briefly sketch...

  14. The magnetic diagnostics subsystem of the LISA Technology Package

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Aguilo, M; Garcia-Berro, E [Departament de Fisica Aplicada, Universitat Politecnica de Catalunya, c/Esteve Terrades, 5, 08860 Castelldefels (Spain); Lobo, A; Mateos, N; Sanjuan, J, E-mail: marc.diaz.aguilo@fa.upc.ed [Institut d' Estudis Espacials de Catalunya, c/Gran Capita 2-4, Edif. Nexus 104, 08034 Barcelona (Spain)

    2010-05-01

    The Magnetic Diagnostics Subsystem of the LISA Technology Package (LTP) on board the LISA Pathfinder (LPF) spacecraft includes a set of four tri-axial fluxgate magnetometers, intended to measure with high precision the magnetic field at the positions they occupy. However, their readouts do not provide a direct measurement of the magnetic field at the positions of the test masses. Therefore, an interpolation method must be implemented to obtain this information. However, such interpolation process faces serious difficulties. Indeed, the size of the interpolation region is excessive for a linear interpolation to be reliable, and the number of magnetometer channels does not provide sufficient data to go beyond that poor approximation. Recent research points to a possible alternative to address the magnetic interpolation problem by means of neural network algorithms. The key point of this approach is the ability neural networks have to learn from suitable training data representing the magnetic field behaviour. Despite the large distance to the test masses and the insufficient magnetic readings, artificial neural networks are able to significantly reduce the estimation error to acceptable levels. The learning efficiency can be best improved by making use of data obtained from on-ground measurements prior to mission launch in all relevant satellite locations and under real operation conditions. Reliable information on that appears to be essential for a meaningful assessment of magnetic noise in the LTP.

  15. The magnetic diagnostics subsystem of the LISA Technology Package

    International Nuclear Information System (INIS)

    Diaz-Aguilo, M; Garcia-Berro, E; Lobo, A; Mateos, N; Sanjuan, J

    2010-01-01

    The Magnetic Diagnostics Subsystem of the LISA Technology Package (LTP) on board the LISA Pathfinder (LPF) spacecraft includes a set of four tri-axial fluxgate magnetometers, intended to measure with high precision the magnetic field at the positions they occupy. However, their readouts do not provide a direct measurement of the magnetic field at the positions of the test masses. Therefore, an interpolation method must be implemented to obtain this information. However, such interpolation process faces serious difficulties. Indeed, the size of the interpolation region is excessive for a linear interpolation to be reliable, and the number of magnetometer channels does not provide sufficient data to go beyond that poor approximation. Recent research points to a possible alternative to address the magnetic interpolation problem by means of neural network algorithms. The key point of this approach is the ability neural networks have to learn from suitable training data representing the magnetic field behaviour. Despite the large distance to the test masses and the insufficient magnetic readings, artificial neural networks are able to significantly reduce the estimation error to acceptable levels. The learning efficiency can be best improved by making use of data obtained from on-ground measurements prior to mission launch in all relevant satellite locations and under real operation conditions. Reliable information on that appears to be essential for a meaningful assessment of magnetic noise in the LTP.

  16. Mona Lisa kuulsa naeratuse saladus leidis lahenduse / Johannes Saar

    Index Scriptorium Estoniae

    Saar, Johannes, 1965-

    2004-01-01

    Firenze kunstiajalooõpetaja Giuseppe Pallanti jõudis 25-aastase arhiivitöö tulemusena järeldusele, et Leonardo da Vinci Mona Lisa modelliks on siidikaupmehe Francesco del Giocondo abikaasa Lisa Gerardini

  17. The Mona Lisa of modern science.

    Science.gov (United States)

    Kemp, Martin

    2003-01-23

    No molecule in the history of science has reached the iconic status of the double helix of DNA. Its image has been imprinted on all aspects of society, from science, art, music, cinema, architecture and advertising. This review of the Mona Lisa of science examines the evolution of its form at the hands of both science and art.

  18. A noise simulator for eLISA: Migrating LISA Pathfinder knowledge to the eLISA mission

    OpenAIRE

    Armano, M.; Audley, H.; Auger, G.; Baird, J.; Binetruy, P.; Born, Michael; Bortoluzzi, D.; Brandt, N.; Bursi, A.; Caleno, M.; Cavalleri, A.; Cesarini, A.; Cruise, M.; Danzmann, Karsten; Diepholz, I.

    2015-01-01

    We present a new technical simulator for the eLISA mission, based on state space modeling techniques and developed in MATLAB. This simulator computes the coordinate and velocity over time of each body involved in the constellation, i.e. the spacecraft and its test masses, taking into account the different disturbances and actuations. This allows studying the contribution of instrumental noises and system imperfections on the residual acceleration applied on the TMs, the latter reflecting the ...

  19. Time-delay interferometry for LISA

    International Nuclear Information System (INIS)

    Tinto, Massimo; Estabrook, F.B.; Armstrong, J.W.

    2002-01-01

    LISA (Laser Interferometer Space Antenna) is a mission to detect and study low-frequency cosmic gravitational radiation through its influence on the phases or frequencies of laser beams exchanged between three remote spacecraft. We previously showed how, with lasers of identical frequencies on stationary spacecraft, the measurement of twelve time series of Doppler shifts could be combined to cancel exactly the phase noise of the lasers and the Doppler fluctuations due to noninertial motions of the six optical benches, while preserving gravitational wave signals. Here we generalize those results on gravitational wave detection with time-delay interferometry to the expected LISA instrument. The six lasers have different center frequencies (in the nominal LISA configuration these center frequencies may well differ by several hundred megahertz) and the distances between spacecraft pairs will change with time (these slowly varying orbital Doppler shifts are expected to be up to tens of megahertz). We develop time-delay data combinations which, as previously, preserve gravitational waves and exactly cancel the leading noise source (phase fluctuations of the six lasers); these data combinations then imply transfer functions for the remaining system noises. Using these, we plot frequency and phase power spectra for modeled system noises in the unequal Michelson combination X and the symmetric Sagnac combination ζ. Although optical bench noise can no longer be cancelled exactly, with the current LISA specifications it is suppressed to negligible levels. It is known that the presently anticipated laser center frequency differences and the orbital Doppler drifts introduce another source of phase noise, arising from the onboard oscillators required to track the photodetector fringes. For the presently planned mission, our analysis indeed demonstrates that noise from current-generation ultrastable oscillators would, if uncorrected, dominate the LISA noise budget. To meet the

  20. LISA Sources in Milky Way Globular Clusters

    Science.gov (United States)

    Kremer, Kyle; Chatterjee, Sourav; Breivik, Katelyn; Rodriguez, Carl L.; Larson, Shane L.; Rasio, Frederic A.

    2018-05-01

    We explore the formation of double-compact-object binaries in Milky Way (MW) globular clusters (GCs) that may be detectable by the Laser Interferometer Space Antenna (LISA). We use a set of 137 fully evolved GC models that, overall, effectively match the properties of the observed GCs in the MW. We estimate that, in total, the MW GCs contain ˜21 sources that will be detectable by LISA. These detectable sources contain all combinations of black hole (BH), neutron star, and white dwarf components. We predict ˜7 of these sources will be BH-BH binaries. Furthermore, we show that some of these BH-BH binaries can have signal-to-noise ratios large enough to be detectable at the distance of the Andromeda galaxy or even the Virgo cluster.

  1. Weak-light phase locking for LISA

    International Nuclear Information System (INIS)

    McNamara, Paul W

    2005-01-01

    The long armlengths of the LISA interferometer, and the finite aperture of the telescope, lead to an optical power attenuation of ∼10 -10 of the transmitted to received light. Simple reflection at the end of the arm is therefore not an optimum interferometric design. Instead, a local laser is offset phase locked to the weak incoming beam, transferring the phase information of the incoming to the outgoing light. This paper reports on an experiment to characterize a weak-light phase-locking scheme suitable for LISA in which a diode-pumped, Nd:YAG, non-planar ring oscillator (NPRO) is offset phase locked to a low-power (13 pW) frequency stabilized master NPRO. Preliminary results of the relative phase noise of the slave laser shows shot noise limited performance above 0.4 Hz. Excess noise is observed at lower frequencies, most probably due to thermal effects in the optical arrangement and phase-sensing electronics

  2. Data Analysis for the LISA Pathfinder Mission

    Science.gov (United States)

    Thorpe, James Ira

    2009-01-01

    The LTP (LISA Technology Package) is the core part of the Laser Interferometer Space Antenna (LISA) Pathfinder mission. The main goal of the mission is to study the sources of any disturbances that perturb the motion of the freely-falling test masses from their geodesic trajectories as well as 10 test various technologies needed for LISA. The LTP experiment is designed as a sequence of experimental runs in which the performance of the instrument is studied and characterized under different operating conditions. In order to best optimize subsequent experimental runs, each run must be promptly analysed to ensure that the following ones make best use of the available knowledge of the instrument ' In order to do this, all analyses must be designed and tested in advance of the mission and have sufficient built-in flexibility to account for unexpected results or behaviour. To support this activity, a robust and flexible data analysis software package is also required. This poster presents two of the main components that make up the data analysis effort: the data analysis software and the mock-data challenges used to validate analysis procedures and experiment designs.

  3. LISA and LISA PathFinder, the endeavour to detect low frequency GWs

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, H [Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BW (United Kingdom); Boatella, C [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain); Chmeissani, M [Institut de Fisica d' Altes Energies (IFAE), Edifici C, Universitat Autonoma de Barcelona, 08193 Bellaterra (Barcelona) (Spain); Conchillo, A [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain); Garcia-Berro, E [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain); Grimani, C [Universita degli Studi di Urbino, and INFN Florence, Istituto di Fisica, Via Santa Chiara 27, 61029 Urbino (Italy); Hajdas, W [Department of Particles and Matter, Paul Scherrer Institut, ODRA 120, 5232 Villigen (Switzerland); Lobo, A [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain); Martinez, L [AtIpic, Parc Tecnologic del Valles, 08290 Cerdanyola del Valles, Barcelona (Spain); Nofrarias, M [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain); Ortega, J A [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain); Puigdengoles, C [Institut de Fisica d' Altes Energies (IFAE), Edifici C, Universitat Autonoma de Barcelona, 08193 Bellaterra (Barcelona) (Spain); Ramos-Castro, J [Departament d' Enginyeria Electronica, UPC, Campus Nord, Edif. C4, Jordi Girona 1-3, 08034 Barcelona (Spain); Sanjuan, J [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain); Wass, P [Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BW (United Kingdom); Xirgu, X [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain)

    2007-05-15

    This is a review about LISA and its technology demonstrator, LISAPathFinder. We first describe the conceptual problems which need to be overcome in order to set up a working interferometric detector of low frequency Gravitational Waves (GW), then summarise the solutions to them as currently conceived by the LISA mission team. This will show that some of these solutions require new technological abilities which are still under development, and which need proper test before being fully implemented. LISAPathFinder (LPF) is the the testbed for such technologies. The final part of the paper will address the ideas and concepts behind the PathFinder as well as their impact on LISA.

  4. LISA and LISA PathFinder, the endeavour to detect low frequency GWs

    International Nuclear Information System (INIS)

    Araujo, H; Boatella, C; Chmeissani, M; Conchillo, A; Garcia-Berro, E; Grimani, C; Hajdas, W; Lobo, A; Martinez, L; Nofrarias, M; Ortega, J A; Puigdengoles, C; Ramos-Castro, J; Sanjuan, J; Wass, P; Xirgu, X

    2007-01-01

    This is a review about LISA and its technology demonstrator, LISAPathFinder. We first describe the conceptual problems which need to be overcome in order to set up a working interferometric detector of low frequency Gravitational Waves (GW), then summarise the solutions to them as currently conceived by the LISA mission team. This will show that some of these solutions require new technological abilities which are still under development, and which need proper test before being fully implemented. LISAPathFinder (LPF) is the the testbed for such technologies. The final part of the paper will address the ideas and concepts behind the PathFinder as well as their impact on LISA

  5. Ground-based self-gravity tests for LISA Pathfinder and LISA

    International Nuclear Information System (INIS)

    Trenkel, C; Warren, C; Wealthy, D

    2009-01-01

    Gravitational coupling between the free-falling test masses and the surrounding spacecraft is one of the dominant noise sources for both LISA Pathfinder and LISA. At present, there are no plans to verify any of the self-gravity requirements by test, on the ground. Here, we explore the possibilities of conducting such tests, using a customised torsion balance. We discuss the main sources of systematic and statistical uncertainty present in such a set-up. Our preliminary assessment indicates that the sensitivity is sufficient to carry out meaningful self-gravity tests.

  6. Data analysis and source modelling for LISA

    International Nuclear Information System (INIS)

    Shang, Yu

    2014-01-01

    The gravitational waves are one of the most important predictions in general relativity. Besides of the directly proof of the existence of GWs, there are already several ground based detectors (such as LIGO, GEO, etc) and the planed future space mission (such as: LISA) which are aim to detect the GWs directly. GW contain a large amount of information of its source, extracting these information can help us dig out the physical property of the source, even open a new window for understanding the Universe. Hence, GW data analysis will be a challenging task in seeking the GWs. In this thesis, I present two works about the data analysis for LISA. In the first work, we introduce an extended multimodal genetic algorithm which utilizes the properties of the signal and the detector response function to analyze the data from the third round of mock LISA data challenge. We have found all five sources present in the data and recovered the coalescence time, chirp mass, mass ratio and sky location with reasonable accuracy. As for the orbital angular momentum and two spins of the Black Holes, we have found a large number of widely separated modes in the parameter space with similar maximum likelihood values. The performance of this method is comparable, if not better, to already existing algorithms. In the second work, we introduce an new phenomenological waveform model for the extreme mass ratio inspiral system. This waveform consists of a set of harmonics with constant amplitude and slowly evolving phase which we decompose in a Taylor series. We use these phenomenological templates to detect the signal in the simulated data, and then, assuming a particular EMRI model, estimate the physical parameters of the binary with high precision. The results show that our phenomenological waveform is very feasible in the data analysis of EMRI signal.

  7. Performance of arm locking in LISA

    International Nuclear Information System (INIS)

    McKenzie, Kirk; Spero, Robert E.; Shaddock, Daniel A.

    2009-01-01

    For the Laser Interferometer Space Antenna (LISA) to reach its design sensitivity, the coupling of the free-running laser frequency noise to the signal readout must be reduced by more than 14 orders of magnitude. One technique employed to reduce the laser frequency noise will be arm locking, where the laser frequency is locked to the LISA arm length. In this paper we detail an implementation of arm locking. We investigate orbital effects (changing arm lengths and Doppler frequencies), the impact of errors in the Doppler knowledge that can cause pulling of the laser frequency, and the noise limit of arm locking. Laser frequency pulling is examined in two regimes: at lock acquisition and in steady state. The noise performance of arm locking is calculated with the inclusion of the dominant expected noise sources: ultrastable oscillator (clock) noise, spacecraft motion, and shot noise. We find that clock noise and spacecraft motion limit the performance of dual arm locking in the LISA science band. Studying these issues reveals that although dual arm locking [A. Sutton and D. A. Shaddock, Phys. Rev. D 78, 082001 (2008)] has advantages over single (or common) arm locking in terms of allowing high gain, it has disadvantages in both laser frequency pulling and noise performance. We address this by proposing a modification to the dual arm-locking sensor, a hybrid of common and dual arm-locking sensors. This modified dual arm-locking sensor has the laser frequency pulling characteristics and low-frequency noise coupling of common arm locking, but retains the control system advantages of dual arm locking. We present a detailed design of an arm-locking controller and perform an analysis of the expected performance when used with and without laser prestabilization. We observe that the sensor phase changes beneficially near unity-gain frequencies of the arm-locking controller, allowing a factor of 10 more gain than previously believed, without degrading stability. With a time

  8. The LISA Pathfinder DMU and Radiation Monitor

    Energy Technology Data Exchange (ETDEWEB)

    Canizares, P; Conchillo, A; Gesa, L; Lloro, I; Lobo, A; Mateos, I; Sopuerta, Carlos F [Institut de Ciencies de l' Espai, CSIC, Facultat de Ciencies, Torre C5 parell, 08193 Bellaterra (Spain); Chmeissani, M [Institut de Fisica d' Altes Energies (IFAE), Edifici CN, UAB Campus, 08193 Bellaterra (Spain); Diaz-Aguilo, M; GarcIa-Berro, E; Gibert, F [Institut d' Estudis Espacials de Catalunya (IEEC), Edifici Nexus, Gran Capita 2-4, 08034 Barcelona (Spain); Grimani, C [Universita degli Studi di Urbino, MFI Department, Via Santa Chiara 27, 61029 Urbino, and INFN Florence (Italy); Nofrarias, M [Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut), Callinstrasse 38, D-30167 Hannover (Germany); Ramos-Castro, J [Departament d' Enginyeria Electronica, UPC, Campus Nord, Edifici C4, Jordi Girona 1-3, 08034 Barcelona (Spain); Sanjuan, J [Department of Physics, University of Florida, NPB-22258 PO Box 118 440, Gainesville, FL 32611-8440 (United States); Araujo, H M; Wass, P, E-mail: lobo@ieec.fcr.es [High Energy Physics Blackett Laboratory, Prince Consort Road, Imperial College London, London SW7 2BW (United Kingdom)

    2011-05-07

    The LISA Pathfinder DMU (Data Management Unit) flight model was formally accepted by ESA and ASD on 11 February 2010, after all hardware and software tests had been successfully completed. The diagnostics items are scheduled to be delivered by the end of 2010. In this paper, we review the requirements and performance of this instrumentation, specially focusing on the Radiation Monitor and the DMU, as well as the status of their programmed use during mission operations, on which work is ongoing at the time of writing.

  9. LISA Beyond Einstein: From the Big Bang to Black Holes. LISA Technology Development at GSFC

    Science.gov (United States)

    Thorpe, James Ira

    2008-01-01

    This viewgraph presentation reviews the work that has been ongoing at the Goddard Space Flight Center (GSFC) in the development of the technology to be used in the Laser Interferometer Space Antenna (LISA) spacecrafts. The prime focus of LISA technology development efforts at NASA/GSFC has been in LISA interferometry. Specifically efforts have been made in the area of laser frequency noise mitigation. Laser frequency noise is addressed through a combination of stabilization and common-mode rejection. Current plans call for two stages of stabilization, pre-stabilization to a local frequency reference and further stabilization using the constellation as a frequency reference. In order for these techniques to be used simultaneously, the pre-stabilization step must provide an adjustable frequency offset. This presentation reports on a modification to the standard modulation/demodulation technique used to stabilize to optical cavities that generates a frequency-tunable reference from a fixed length cavity. This technique requires no modifications to the cavity itself and only minor modifications to the components. The measured noise performance and dynamic range of the laboratory prototype meet the LISA requirements.

  10. Optical testbed for the LISA phasemeter

    International Nuclear Information System (INIS)

    Schwarze, T S; Fernández Barranco, G; Penkert, D; Gerberding, O; Heinzel, G; Danzmann, K

    2016-01-01

    The planned spaceborne gravitational wave detector LISA will allow the detection of gravitational waves at frequencies between 0.1 mHz and 1 Hz. A breadboard model for the metrology system aka the phasemeter was developed in the scope of an ESA technology development project by a collaboration between the Albert Einstein Institute, the Technical University of Denmark and the Danish industry partner Axcon Aps. It in particular provides the electronic readout of the main interferometer phases besides auxiliary functions. These include clock noise transfer, ADC pilot tone correction, inter-satellite ranging and data transfer. Besides in LISA, the phasemeter can also be applied in future satellite geodesy missions. Here we show the planning and advances in the implementation of an optical testbed for the full metrology chain. It is based on an ultra-stable hexagonal optical bench. This bench allows the generation of three unequal heterodyne beatnotes with a zero phase combination, thus providing the possibility to probe the phase readout for non-linearities in an optical three signal test. Additionally, the utilization of three independent phasemeters will allow the testing of the auxiliary functions. Once working, components can individually be replaced with flight-qualified hardware in this setup. (paper)

  11. Optical testbed for the LISA phasemeter

    Science.gov (United States)

    Schwarze, T. S.; Fernández Barranco, G.; Penkert, D.; Gerberding, O.; Heinzel, G.; Danzmann, K.

    2016-05-01

    The planned spaceborne gravitational wave detector LISA will allow the detection of gravitational waves at frequencies between 0.1 mHz and 1 Hz. A breadboard model for the metrology system aka the phasemeter was developed in the scope of an ESA technology development project by a collaboration between the Albert Einstein Institute, the Technical University of Denmark and the Danish industry partner Axcon Aps. It in particular provides the electronic readout of the main interferometer phases besides auxiliary functions. These include clock noise transfer, ADC pilot tone correction, inter-satellite ranging and data transfer. Besides in LISA, the phasemeter can also be applied in future satellite geodesy missions. Here we show the planning and advances in the implementation of an optical testbed for the full metrology chain. It is based on an ultra-stable hexagonal optical bench. This bench allows the generation of three unequal heterodyne beatnotes with a zero phase combination, thus providing the possibility to probe the phase readout for non-linearities in an optical three signal test. Additionally, the utilization of three independent phasemeters will allow the testing of the auxiliary functions. Once working, components can individually be replaced with flight-qualified hardware in this setup.

  12. Detection of Micrometeoroids with LISA Pathfinder

    Science.gov (United States)

    Thorpe, Ira; Littenberg, Tyson; Janchez, Diego; Baker, John; The LISA Pathfinder Team Team

    2017-01-01

    The LISA Pathfinder mission (LPF), a joint ESA/NASA technology demonstration mission currently operating at the Sun-Earth L1 point, contains the most precise accelerometry system ever flown. Analysis suggests that LPF should have sufficient sensitivity to detect impacts of small micrometeoroids and dust through their transfer of momentum to the spacecraft. Moreover, LPF's ability to fully resolve both the linear and angular momentum transfer in three dimensions allows a magnitude, direction, and location to be estimated for each impact. We present preliminary results from a systematic search of the LISA Pathfinder data for such impacts and discuss the prospects for using these and future results to inform models of the formation and evolution of dust populations in the inner solar system. These models have wide applicability to both pure and applied space science, ranging from the physics of planet formation and dynamics of minor Solar System bodies to estimates of the micrometeorite hazard for future spacecraft. 2017 NASA Science Innovation Fund.

  13. LISA as a dark energy probe

    International Nuclear Information System (INIS)

    Arun, K G; Mishra, Chandra Kant; Iyer, B R; Sinha, Siddhartha; Van Den Broeck, Chris; Sathyaprakash, B S

    2009-01-01

    Recently, it has been shown that the inclusion of higher signal harmonics in the inspiral signals of binary supermassive black holes (SMBH) leads to dramatic improvements in the parameter estimation with Laser Interferometer Space Antenna (LISA). In particular, the angular resolution becomes good enough to identify the host galaxy or galaxy cluster, in which case the redshift can be determined by electromagnetic means. The gravitational wave signal also provides the luminosity distance with high accuracy, and the relationship between this and the redshift depends sensitively on the cosmological parameters, such as the equation-of-state parameter w = p DE /ρ DE of dark energy. Using binary SMBH events at z < 1 with appropriate masses and orientations, one would be able to constrain w to within a few per cent. We show that, if the measured sky location is folded into the error analysis, the uncertainty on w goes down by an additional factor of 2-3, leaving weak lensing as the only limiting factor in using LISA as a dark energy probe.

  14. Interferometry for the LISA technology package LTP: an update

    International Nuclear Information System (INIS)

    Heinzel, G; Bogenstahl, J; Braxmaier, C; Danzmann, K; Garcia, A; Guzman, F; Hough, J; Hoyland, D; Jennrich, O; Killow, C; Robertson, D; Sodnik, Z; Steier, F; Ward, H; Wand, V

    2006-01-01

    This paper gives an update on the status of the LISA technology package (LTP) which is to be launched in 2009 by ESA as a technology demonstration mission for the spaceborne gravitational wave observatory LISA. The dominant noise source in the interferometer prototype has been investigated and improved such that it is now comfortably below its budget at all frequencies

  15. Fundamentals of the LISA stable flight formation

    International Nuclear Information System (INIS)

    Dhurandhar, S V; Nayak, K Rajesh; Koshti, S; Vinet, J-Y

    2005-01-01

    The joint NASA-ESA mission, LISA, relies crucially on the stability of the three-spacecraft constellation. Each of the spacecraft is in heliocentric orbit forming a stable triangle. In this paper we explicitly show with the help of the Clohessy-Wiltshire equations that any configuration of spacecraft lying in the planes making angles of ±60 0 with the ecliptic and given suitable initial velocities within the plane, can be made stable in the sense that the inter-spacecraft distances remain constant to first order in the dimensions of the configuration compared with the distance to the Sun. Such analysis would be useful in order to carry out theoretical studies on the optical links, simulators, etc

  16. Charge Management in LISA Pathfinder: The Continuous Discharging Experiment

    Science.gov (United States)

    Ewing, Becca Elizabeth

    2018-01-01

    Test mass charging is a significant source of excess force and force noise in LISA Pathfinder (LPF). The planned design scheme for mitigation of charge induced force noise in LISA is a continuous discharge by UV light illumination. We report on analysis of a charge management experiment on-board LPF conducted during December 2016. We discuss the measurement of test mass charging noise with and without continuous UV illumination, in addition to the dynamic response in the continuous discharge scheme. Results of the continuous discharge system will be discussed for their application to operating LISA with lower test mass charge.

  17. Dual-Cylinder Laser Reference Cavities for LISA Project

    Data.gov (United States)

    National Aeronautics and Space Administration — "Summary: The Laser Interferometer Space Antenna (LISA) mission is under consideration by NASA and ESA as a joint mission to study gravitational wave signals from a...

  18. Gravitational Reference Sensor Front-End Electronics Simulator for LISA

    International Nuclear Information System (INIS)

    Meshksar, Neda; Ferraioli, Luigi; Mance, Davor; Zweifel, Peter; Giardini, Domenico; Ten Pierick, Jan

    2017-01-01

    At the ETH Zurich we are developing a modular simulator that provides a realistic simulation of the Front End Electronics (FEE) for LISA Gravitational Reference Sensor (GRS). It is based on the GRS FEE-simulator already implemented for LISA Pathfinder. It considers, in particular, the non-linearity and the critical details of hardware, such as the non-linear multiplicative noise caused by voltage reference instability, test mass charging and detailed actuation and sensing algorithms. We present the simulation modules, considering the above-mentioned features. Based on the ETH GRS FEE-simulator for LISA Pathfinder we aim to develop a modular simulator that provides a realistic simulation of GRS FEE for LISA. (paper)

  19. LISA and its in-flight test precursor SMART-2

    International Nuclear Information System (INIS)

    Vitale, S.; Bender, P.; Brillet, A.; Buchman, S.; Cavalleri, A.; Cerdonio, M.; Cruise, M.; Cutler, C.; Danzmann, K.; Dolesi, R.; Folkner, W.; Gianolio, A.; Jafry, Y.; Hasinger, G.; Heinzel, G.; Hogan, C.; Hueller, M.; Hough, J.; Phinney, S.; Prince, T.; Richstone, D.; Robertson, D.; Rodrigues, M.; Ruediger, A.; Sandford, M.; Schilling, R.; Shoemaker, D.; Schutz, B.; Stebbins, R.; Stubbs, C.; Sumner, T.; Thorne, K.; Tinto, M.; Touboul, P.; Ward, H.; Weber, W.; Winkler, W.

    2002-01-01

    LISA will be the first space-home gravitational wave observatory. It aims to detect gravitational waves in the 0.1 mHz/1 Hz range from sources including galactic binaries, super-massive black-hole binaries, capture of objects by super-massive black-holes and stochastic background. LISA is an ESA approved Cornerstone Mission foreseen as a joint ESA-NASA endeavour to be launched in 2010-11. The principle of operation of LISA is based on laser ranging of test-masses under pure geodesic motion. Achieving pure geodesic motion at the level requested for LISA, 3x10 -15 ms -2 /√Hz at 0.1 mHz, is considered a challenging technological objective. To reduce the risk, both ESA and NASA are pursuing an in-flight test of the relevant technology. The goal of the test is to demonstrate geodetic motion within one order of magnitude from the LISA performance. ESA has given this test as the primary goal of its technology dedicated mission SMART-2 with a launch in 2006. This paper describes the basics of LISA, its key technologies, and its in-flight precursor test on SMART-2

  20. A UV LED-based Charge Management System for LISA

    Science.gov (United States)

    Conklin, John W.; Chilton, Andrew; Olatunde, Taiwo Janet; Apple, Stephen; Parry, Samantha; Ciani, Giacomo; Wass, Peter; Mueller, Guido

    2018-01-01

    The Laser Interferometer Space Antenna (LISA) will be the first space instrument to observe gravitational waves in the millihertz frequency band. LISA consists of three Sun-orbiting spacecraft that form an equilateral triangle, with each side measuring 2.5 million kilometers in length. Each spacecraft houses two free-floating test masses, which are protected from all disturbing forces so that they follow pure geodesics in spacetime. A drag-free control system commands micronewton thrusters to force the spacecraft to fly in formation with the test masses and laser interferometers measure the minute variations in the distance, or light travel time, between these free-falling test masses caused by gravitational waves. The LISA observatory, with a planned launch in the early 2030s, is led by the European Space Agency with significant contributions from NASA. Recently, NASA has initiated strategic investments in key LISA technologies that will likely become U.S. flight hardware contributions to this ground-breaking mission. One of these payload elements is the Charge Management System (CMS), which controls the electric potential of the test masses relative to their housings to reduce spurious force noise acting on the test masses to below the required level. This talk, presented by University of Florida team that leads the CMS development, will describe this vital U.S. contribution to the LISA mission in the context of the envisioned LISA payload architecture and its in-flight sensitivity to gravitational waves.

  1. Distinguishing Between Formation Channels for Binary Black Holes with LISA

    Science.gov (United States)

    Breivik, Katelyn; Rodriguez, Carl L.; Larson, Shane L.; Kalogera, Vassiliki; Rasio, Frederic A.

    2017-01-01

    The recent detections of GW150914 and GW151226 imply an abundance of stellar-mass binary-black-hole mergers in the local universe. While ground-based gravitational-wave detectors are limited to observing the final moments before a binary merges, space-based detectors, such as the Laser Interferometer Space Antenna (LISA), can observe binaries at lower orbital frequencies where such systems may still encode information about their formation histories. In particular, the orbital eccentricity and mass of binary black holes in the LISA frequency band can be used together to discriminate between binaries formed in isolation in galactic fields and those formed in dense stellar environments such as globular clusters. In this letter, we explore the orbital eccentricity and mass of binary-black-hole populations as they evolve through the LISA frequency band. Overall we find that there are two distinct populations discernible by LISA. We show that up to ~90% of binaries formed either dynamically or in isolation have eccentricities measurable by LISA. Finally, we note how measured eccentricities of low-mass binary black holes evolved in isolation could provide detailed constraints on the physics of black-hole natal kicks and common-envelope evolution.

  2. LISA Pathfinder: hardware tests and their input to the mission

    Science.gov (United States)

    Audley, Heather

    The Laser Interferometer Space Antenna (LISA) is a joint ESA-NASA mission for the first space-borne gravitational wave detector. LISA aims to detect sources in the 0.1mHz to 1Hz range, which include supermassive black holes and galactic binary stars. Core technologies required for the LISA mission, including drag-free test mass control, picometre interferometry and micro-Newton thrusters, cannot be tested on-ground. Therefore, a precursor satellite, LISA Pathfinder, has been developed as a technology demonstration mission. The preparations for the LISA Pathfinder mission have reached an exciting stage. Tests of the engineering model of the optical metrology system have recently been completed at the Albert Einstein Institute, Hannover, and flight model tests are now underway. Significantly, they represent the first complete integration and testing of the space-qualified hardware and are the first tests on system level. The results and test procedures of these campaigns will be utilised directly in the ground-based flight hardware tests, and subsequently within in-flight operations. In addition, they allow valuable testing of the data analysis methods using the MatLab based LTP data analysis toolbox. This contribution presents an overview of the test campaigns calibration, control and perfor-mance results, focusing on the implications for the Experimental Master Plan which provides the basis for the in-flight operations and procedures.

  3. Accreting Double White Dwarf Binaries: Implications for LISA

    Energy Technology Data Exchange (ETDEWEB)

    Kremer, Kyle; Breivik, Katelyn; Larson, Shane L.; Kalogera, Vassiliki, E-mail: kremer@u.northwestern.edu, E-mail: katelyn.breivik@northwestern.edu, E-mail: vicky@northwestern.edu, E-mail: s.larson@northwestern.edu [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Department of Physics and Astronomy, Northwestern University 2145 Sheridan Road, Evanston, IL 60201 (United States)

    2017-09-10

    We explore the long-term evolution of mass-transferring white dwarf (WD) binaries undergoing both direct-impact and disk accretion and explore implications of such systems to gravitational-wave (GW) astronomy. We cover a broad range of initial component masses and show that these systems, the majority of which lie within the Laser Interferometer Space Antenna ( LISA ) sensitivity range, exhibit prominent negative orbital frequency evolution (chirp) for a significant fraction of their lifetimes. Using a galactic population synthesis, we predict ∼2700 of these systems will be observable with a negative chirp of 0.1 yr{sup −2} by a space-based GW detector like LISA . We also show that detections of mass-transferring double WD systems by LISA may provide astronomers with unique ways of probing the physics governing close compact object binaries.

  4. Accreting Double White Dwarf Binaries: Implications for LISA

    Science.gov (United States)

    Kremer, Kyle; Breivik, Katelyn; Larson, Shane L.; Kalogera, Vassiliki

    2017-09-01

    We explore the long-term evolution of mass-transferring white dwarf (WD) binaries undergoing both direct-impact and disk accretion and explore implications of such systems to gravitational-wave (GW) astronomy. We cover a broad range of initial component masses and show that these systems, the majority of which lie within the Laser Interferometer Space Antenna (LISA) sensitivity range, exhibit prominent negative orbital frequency evolution (chirp) for a significant fraction of their lifetimes. Using a galactic population synthesis, we predict ˜2700 of these systems will be observable with a negative chirp of 0.1 yr-2 by a space-based GW detector like LISA. We also show that detections of mass-transferring double WD systems by LISA may provide astronomers with unique ways of probing the physics governing close compact object binaries.

  5. Bayesian statistics for the calibration of the LISA Pathfinder experiment

    International Nuclear Information System (INIS)

    Armano, M; Freschi, M; Audley, H; Born, M; Danzmann, K; Diepholz, I; Auger, G; Binetruy, P; Bortoluzzi, D; Brandt, N; Fitzsimons, E; Bursi, A; Caleno, M; Cavalleri, A; Cesarini, A; Dolesi, R; Ferroni, V; Cruise, M; Dunbar, N; Ferraioli, L

    2015-01-01

    The main goal of LISA Pathfinder (LPF) mission is to estimate the acceleration noise models of the overall LISA Technology Package (LTP) experiment on-board. This will be of crucial importance for the future space-based Gravitational-Wave (GW) detectors, like eLISA. Here, we present the Bayesian analysis framework to process the planned system identification experiments designed for that purpose. In particular, we focus on the analysis strategies to predict the accuracy of the parameters that describe the system in all degrees of freedom. The data sets were generated during the latest operational simulations organised by the data analysis team and this work is part of the LTPDA Matlab toolbox. (paper)

  6. Accreting Double White Dwarf Binaries: Implications for LISA

    International Nuclear Information System (INIS)

    Kremer, Kyle; Breivik, Katelyn; Larson, Shane L.; Kalogera, Vassiliki

    2017-01-01

    We explore the long-term evolution of mass-transferring white dwarf (WD) binaries undergoing both direct-impact and disk accretion and explore implications of such systems to gravitational-wave (GW) astronomy. We cover a broad range of initial component masses and show that these systems, the majority of which lie within the Laser Interferometer Space Antenna ( LISA ) sensitivity range, exhibit prominent negative orbital frequency evolution (chirp) for a significant fraction of their lifetimes. Using a galactic population synthesis, we predict ∼2700 of these systems will be observable with a negative chirp of 0.1 yr −2 by a space-based GW detector like LISA . We also show that detections of mass-transferring double WD systems by LISA may provide astronomers with unique ways of probing the physics governing close compact object binaries.

  7. LISA package user guide. Part II: LISA (Long Term Isolation Safety Assessment) program description and user guide

    International Nuclear Information System (INIS)

    Prado, P.; Saltelli, A.; Homma, T.

    1992-01-01

    This manual is subdivided into three parts. In this second part, this document describes the LISA (Long term Isolation Safety Assessment) Code and its submodels. LISA is a tool for analysis of the safety of an underground disposal of nuclear waste. It has the capability to handle nuclide chain of arbitrary length and to evaluate the migration of nuclide through a geosphere medium composed of an arbitrary number of segments. LISA makes use of Monte Carlo methodology to evaluate the uncertainty in the quantity being assessed (eg dose) arising from the uncertainty in the model input parameters. In the present version LISA is equipped with a very simple source term submodel, a relatively complex geosphere and a simplified biosphere. The code is closely associated with its statistical pre-processor code (PREP), which generates the input Monte Carlo sample from the assigned parameter probability density functions and with its post-processor code (SPOP) which provides useful statistics on the output sample (uncertainty and sensitivity analysis). This report describes the general structure of LISA, its subroutines and submodels, the code input ant output files. It is intended to provide the user with enough information to know and run the code as well as the capacity to incorporate different submodels. 15 refs., 6 figs

  8. The Breadboard model of the LISA telescope assembly

    Science.gov (United States)

    Lucarelli, S.; Scheulen, D.; Kemper, D.; Sippel, R.; Verlaan, A.; Hogenhuis, H.; Ende, D.

    2017-11-01

    The primary goal of the LISA mission is the detection of gravitational waves from astronomical sources in a frequency range of 10-4 to 1 Hz. This requires operational stabilities in the picometer range as well as highly predictable mechanical distortions upon cooling down, outgassing in space, and gravity release. In March 2011 ESA announced a new way forward for the Lclass candidate missions, including LISA. ESA and the scientific community are now studying options for European-only missions that offer a significant reduction of the costs, while maintaining their core science objectives. In this context LISA has become the New Gravitational wave Observatory (NGO). Despite this reformulation, the need for dimensional stability in the picometer range remains valid, and ESA have continued the corresponding LISA Technology Development Activities (TDA's) also in view of NGO. In such frame Astrium GmbH and xperion (Friedrichshafen, Germany) have designed and manufactured an ultra-stable CFRP breadboard of the LISA telescope in order to experimentally demonstrate that the structure and the M1 & M2 mirror mounts are fulfilling the LISA requirements in the mission operational thermal environment. Suitable techniques to mount the telescope mirrors and to support the M1 & M2 mirrors have been developed, with the aim of measuring a system CTE of less than 10-7 K-1 during cooling down to -80°C. Additionally to the stringent mass and stiffness specifications, the required offset design makes the control of relative tilts and lateral displacements between the M1 and M2 mirrors particularly demanding. The thermo-elastic performance of the telescope assembly is going to be experimentally verified by TNO (Delft, The Netherlands) starting from the second half of 2012. This paper addresses challenges faced in the design phase, shows the resulting hardware and present first outcomes of the test campaign performed at TNO.

  9. Inference on inspiral signals using LISA MLDC data

    International Nuclear Information System (INIS)

    Roever, Christian; Stroeer, Alexander; Bloomer, Ed; Christensen, Nelson; Clark, James; Hendry, Martin; Messenger, Chris; Meyer, Renate; Pitkin, Matt; Toher, Jennifer; Umstaetter, Richard; Vecchio, Alberto; Veitch, John; Woan, Graham

    2007-01-01

    In this paper, we describe a Bayesian inference framework for the analysis of data obtained by LISA. We set up a model for binary inspiral signals as defined for the Mock LISA Data Challenge 1.2 (MLDC), and implemented a Markov chain Monte Carlo (MCMC) algorithm to facilitate exploration and integration of the posterior distribution over the nine-dimensional parameter space. Here, we present intermediate results showing how, using this method, information about the nine parameters can be extracted from the data

  10. LISA Pathfinder: Optical Metrology System monitoring during operations

    Science.gov (United States)

    Audley, Heather E.; LISA Pathfinder Collaboration

    2017-05-01

    The LISA Pathfinder (LPF) mission has demonstrated excellent performance. In addition to having surpassed the main mission goals, data has been collected from the various subsystems throughout the duration of the mission. This data is a valuable resource, both for a more complete understanding of the LPF satellite and the differential acceleration measurements, as well as for the design of the future Laser Interferometer Space Antenna (LISA) mission. Initial analysis of the Optical Metrology System (OMS) data was performed as part of daily system monitoring, and more in-depth analyses are ongoing. This contribution presents an overview of these activities along with an introduction to the OMS.

  11. E. Yiannopoulou on Lisa Blackman’s The Body.

    Directory of Open Access Journals (Sweden)

    2009-11-01

    Full Text Available Blackman, Lisa. The Body. Oxford and New York: Berg, 2008. 160 pp. “Is there anything natural about the human body?” (1. This is how Lisa Blackman begins her all too daunting task of reviewing and critically evaluating what has come to be known as “body theory” in the field of sociology. Carefully picking her way among numerous theories on the corporeal that have been produced across the humanities in the last twenty years, Blackman lays out her problematic from the start by asking to know w...

  12. 240 nm UV LEDs for LISA test mass charge control

    Science.gov (United States)

    Olatunde, Taiwo; Shelley, Ryan; Chilton, Andrew; Serra, Paul; Ciani, Giacomo; Mueller, Guido; Conklin, John

    2015-05-01

    Test Masses inside the LISA Gravitational Reference Sensor must maintain almost pure geodesic motion for gravitational waves to be successfully detected. LISA requires residual test mass accelerations below 3 fm/s2/√Hz at all frequencies between 0.1 and 3 mHz. One of the well-known noise sources is associated with the charges on the test masses which couple to stray electrical potentials and external electromagnetic fields. LISA Pathfinder will use Hg-discharge lamps emitting mostly around 254 nm to discharge the test masses via photoemission in its 2015/16 flight. A future LISA mission launched around 2030 will likely replace the lamps with newer UV-LEDs. Presented here is a preliminary study of the effectiveness of charge control using latest generation UV-LEDs which produce light at 240 nm with energy above the work function of pure Au. Their lower mass, better power efficiency and small size make them an ideal replacement for Hg lamps.

  13. 240 nm UV LEDs for LISA test mass charge control

    International Nuclear Information System (INIS)

    Olatunde, Taiwo; Shelley, Ryan; Chilton, Andrew; Serra, Paul; Ciani, Giacomo; Mueller, Guido; Conklin, John

    2015-01-01

    Test Masses inside the LISA Gravitational Reference Sensor must maintain almost pure geodesic motion for gravitational waves to be successfully detected. LISA requires residual test mass accelerations below 3 fm/s 2 /√Hz at all frequencies between 0.1 and 3 mHz. One of the well-known noise sources is associated with the charges on the test masses which couple to stray electrical potentials and external electromagnetic fields. LISA Pathfinder will use Hg-discharge lamps emitting mostly around 254 nm to discharge the test masses via photoemission in its 2015/16 flight. A future LISA mission launched around 2030 will likely replace the lamps with newer UV-LEDs. Presented here is a preliminary study of the effectiveness of charge control using latest generation UV-LEDs which produce light at 240 nm with energy above the work function of pure Au. Their lower mass, better power efficiency and small size make them an ideal replacement for Hg lamps. (paper)

  14. Multi-Messenger Astronomy: White Dwarf Binaries, LISA and GAIA

    Science.gov (United States)

    Bueno, Michael; Breivik, Katelyn; Larson, Shane L.

    2017-01-01

    The discovery of gravitational waves has ushered in a new era in astronomy. The low-frequency band covered by the future LISA detector provides unprecedented opportunities for multi-messenger astronomy. With the Global Astrometric Interferometer for Astrophysics (GAIA) mission, we expect to discover about 1,000 eclipsing binary systems composed of a WD and a main sequence star - a sizeable increase from the approximately 34 currently known binaries of this type. In advance of the first GAIA data release and the launch of LISA within the next decade, we used the Binary Stellar Evolution (BSE) code simulate the evolution of White Dwarf Binaries (WDB) in a fixed galaxy population of about 196,000 sources. Our goal is to assess the detectability of a WDB by LISA and GAIA using the parameters from our population synthesis, we calculate GW strength h, and apparent GAIA magnitude G. We can then use a scale factor to make a prediction of how many multi- messenger sources we expect to be detectable by both LISA and GAIA in a galaxy the size of the Milky Way. We create binaries 10 times to ensure randomness in distance assignment and average our results. We then determined whether or not astronomical chirp is the difference between the total chirp and the GW chirp. With Astronomical chirp and simulations of mass transfer and tides, we can gather more information about the internal astrophysics of stars in ultra-compact binary systems.

  15. Professor Lisa Aranson on JA Green (a pioonier artist photographer ...

    African Journals Online (AJOL)

    Jonathan Adagogo Green's photographic and artistic contributions working in his countryside, the Niger Delta of Nigeria is reviewed by Professor Lisa Aranson. Aranson in a public lecture presentation on the stand-point of art history thinks of J.A. Green as having operated in two worlds of which he is said to have initiated in ...

  16. 77 FR 56647 - Lisa Jean Sharp: Debarment Order

    Science.gov (United States)

    2012-09-13

    ... Act (the FD&C Act) permanently debarring Lisa Jean Sharp from providing services in any capacity to a...&C Act. Ms. Sharp was given notice of the proposed permanent debarment and an opportunity to request... drug product under the FD&C Act. The factual basis for this conviction is as follows: Ms. Sharp was the...

  17. Sensitivity and parameter-estimation precision for alternate LISA configurations

    International Nuclear Information System (INIS)

    Vallisneri, Michele; Crowder, Jeff; Tinto, Massimo

    2008-01-01

    We describe a simple framework to assess the LISA scientific performance (more specifically, its sensitivity and expected parameter-estimation precision for prescribed gravitational-wave signals) under the assumption of failure of one or two inter-spacecraft laser measurements (links) and of one to four intra-spacecraft laser measurements. We apply the framework to the simple case of measuring the LISA sensitivity to monochromatic circular binaries, and the LISA parameter-estimation precision for the gravitational-wave polarization angle of these systems. Compared to the six-link baseline configuration, the five-link case is characterized by a small loss in signal-to-noise ratio (SNR) in the high-frequency section of the LISA band; the four-link case shows a reduction by a factor of √2 at low frequencies, and by up to ∼2 at high frequencies. The uncertainty in the estimate of polarization, as computed in the Fisher-matrix formalism, also worsens when moving from six to five, and then to four links: this can be explained by the reduced SNR available in those configurations (except for observations shorter than three months, where five and six links do better than four even with the same SNR). In addition, we prove (for generic signals) that the SNR and Fisher matrix are invariant with respect to the choice of a basis of TDI observables; rather, they depend only on which inter-spacecraft and intra-spacecraft measurements are available

  18. GRS vs. OMS Calibration in LISA Pathfinder Data Analysis

    International Nuclear Information System (INIS)

    Meshksar, Neda; Ferraioli, Luigi; Mance, Davor; Zweifel, Peter; Giardini, Domenico; Ten Pierick, Jan

    2017-01-01

    On board LISA Pathfinder spacecraft the test mass displacement along the main measurement axis is sensed in two different ways: optically and electrostatically. We have monitored the relative calibration between the two measurements during the mission science phase. The trend sensitivity of the relative calibration has been computed for different physical parameters, such as temperature, magnetic field, test mass bias voltage and current. (paper)

  19. LISA data analysis using Markov chain Monte Carlo methods

    International Nuclear Information System (INIS)

    Cornish, Neil J.; Crowder, Jeff

    2005-01-01

    The Laser Interferometer Space Antenna (LISA) is expected to simultaneously detect many thousands of low-frequency gravitational wave signals. This presents a data analysis challenge that is very different to the one encountered in ground based gravitational wave astronomy. LISA data analysis requires the identification of individual signals from a data stream containing an unknown number of overlapping signals. Because of the signal overlaps, a global fit to all the signals has to be performed in order to avoid biasing the solution. However, performing such a global fit requires the exploration of an enormous parameter space with a dimension upwards of 50 000. Markov Chain Monte Carlo (MCMC) methods offer a very promising solution to the LISA data analysis problem. MCMC algorithms are able to efficiently explore large parameter spaces, simultaneously providing parameter estimates, error analysis, and even model selection. Here we present the first application of MCMC methods to simulated LISA data and demonstrate the great potential of the MCMC approach. Our implementation uses a generalized F-statistic to evaluate the likelihoods, and simulated annealing to speed convergence of the Markov chains. As a final step we supercool the chains to extract maximum likelihood estimates, and estimates of the Bayes factors for competing models. We find that the MCMC approach is able to correctly identify the number of signals present, extract the source parameters, and return error estimates consistent with Fisher information matrix predictions

  20. GRS vs. OMS Calibration in LISA Pathfinder Data Analysis

    Science.gov (United States)

    Meshksar, Neda; Ferraioli, Luigi; Mance, Davor; ten Pierick, Jan; Zweifel, Peter; Giardini, Domenico; ">LISA Pathfinder colaboration, LISA Pathfinder spacecraft the test mass displacement along the main measurement axis is sensed in two different ways: optically and electrostatically. We have monitored the relative calibration between the two measurements during the mission science phase. The trend sensitivity of the relative calibration has been computed for different physical parameters, such as temperature, magnetic field, test mass bias voltage and current.

  1. The Engineering of LISA Pathfinder – the quietest Laboratory ever flown in Space

    International Nuclear Information System (INIS)

    Trenkel, Christian; Wealthy, Dave; Dunbar, Neil; Warren, Carl; Schleicher, Alexander; Ziegler, Tobias; Brandt, Nico; Gerndt, Rüdiger

    2017-01-01

    We review the engineering approach adopted to ensure the required gravitational, magnetic, thermal and residual acceleration stability on-board LISA Pathfinder, and present the in-flight results that have been achieved. Arguably, this stability makes LISA Pathfinder the quietest laboratory ever flown in space. The implications for LISA are also discussed. (paper)

  2. Programme [11. international LISA symposium, Zurich (Switzerland), 5-9 September 2016

    International Nuclear Information System (INIS)

    2017-01-01

    Monday, 5th of September 2016 Chair: M. Colpi S. Vitale The LTP experiment on LISA Pathfinder and its first results K. Dooley Advanced LIGO: news from the dark universe B. Schutz LIGOs Black Holes and Science in the LISA Era P. McNamara LISA Pathfinder: First steps to observing gravitational waves from space M. Hewitson In-flight Performance of the Optical Metrology System on LISA Pathfinder W. Weber Physical model of the LISA Pathfinder differential acceleration measurement and its application to LISA K. Danzmann The Status of LISA Chair: O. Jennrich J. Martino On-flight characterization of Coldgas micro-Newton thrusters for Lisa Pathfinder M. Nofrarias Magnetic force noise in LISA Pathfinder L. Ferraioli The LISA Pathfinder GRS Front-End Electronics D. Vetrugno The Δ g workflow: from measured displacements to the differential external acceleration. A. Wittchen Coupling of relative intensity noise and pathlength noise to the length measurement in the optical metrology system of LISA Pathfinder S. Paczkowski Laser frequency stabilisation and interferometer path length differences on LISA Pathfinder R. Giusteri The free-fall mode experiment on LISA Pathfinder: first results P. Wass Electrostatic test-mass force-noise disturbances as measured by LISA Pathfinder R. Dolesi The contribution of Brownian noise from viscous gas damping to the differential acceleration noise measured in LISA Pathfinder between two nominally free falling test masses C. Trenkel The engineering of LISA Pathfinder – the quietest laboratory ever flown in space W. Klipstein LISA-derived Flight Phasemeter on the GRACE Follow-On Mission P. Laufer MEMS Ion Thruster Chips to Significantly Enhance Cold Gas Thruster Lifetime for LISA M. Tinto Enhanced Gravitational Wave Science with LISA and gLISA Tuesday, 6th of September 2016 Chair: P. McNamara F. Ricci Advanced VIRGO: State of the Art C. Belczynski Evolutionary predictions in the advanced LIGO/Virgo era A. Sesana The promise of multi

  3. Description of charging/discharging processes of the LISA sensors

    International Nuclear Information System (INIS)

    Sumner, Tim; Araujo, Henrique; Davidge, David; Howard, Alex; Lee, Chris; Rochester, Geoff; Shaul, Diana; Wass, Peter

    2004-01-01

    The next generation of gravitational experiments in space is likely to use completely isolated proof-masses. For example, LISA uses proof-masses as mirrors in interferometers for gravitational wave astronomy (Bender et al 1998 Pre-phase A report MPG-233 pp 1-191) and STEP uses proof-masses in Earth orbit for an equivalence principle test (Sumner et al 2003 at press). Nongravitational forces will act on these proof-masses if they become charged, through the action of cosmic rays and solar flare particles for example. This paper examines the consequences of proof-mass charging for LISA, and presents results from using GEANT4 to assess the charging processes. Finally, there is a brief discussion of a means of controlling the charge down to an acceptable level

  4. LISA Sources in Milky Way Globular Clusters.

    Science.gov (United States)

    Kremer, Kyle; Chatterjee, Sourav; Breivik, Katelyn; Rodriguez, Carl L; Larson, Shane L; Rasio, Frederic A

    2018-05-11

    We explore the formation of double-compact-object binaries in Milky Way (MW) globular clusters (GCs) that may be detectable by the Laser Interferometer Space Antenna (LISA). We use a set of 137 fully evolved GC models that, overall, effectively match the properties of the observed GCs in the MW. We estimate that, in total, the MW GCs contain ∼21 sources that will be detectable by LISA. These detectable sources contain all combinations of black hole (BH), neutron star, and white dwarf components. We predict ∼7 of these sources will be BH-BH binaries. Furthermore, we show that some of these BH-BH binaries can have signal-to-noise ratios large enough to be detectable at the distance of the Andromeda galaxy or even the Virgo cluster.

  5. The first mock data challenge for LISA Pathfinder

    Energy Technology Data Exchange (ETDEWEB)

    Monsky, A; Hewitson, M; Wanner, G; Nofrarias, M; Diepholz, I; Danzmann, K [Albert-Einstein-Institut, Max-Planck-Institut fuer Gravitationsphysik und Universitaet Hannover, 30167 Hannover (Germany); Ferraioli, L; Hueller, M; Cavalleri, A; Ciani, G; Dolesi, R [Dipartimento di Fisica, Universita di Trento and INFN, Gruppo Collegato di Trento, 38050 Povo, Trento (Italy); Grynagier, A [Institut fuer Flugmechanik und Flugregelung, 70569 Stuttgart (Germany); Armano, M [European Space Agency, ESAC, Villanueva de la Canada, 28692 Madrid (Spain); Benedetti, M [Dipartimento di Ingegneria dei Materiali e Tecnologie Industriali, Universita di Trento and INFN, Gruppo Collegato di Trento, Mesiano, Trento (Italy); Bogenstahl, J [Department of Physics and Astronomy, University of Glasgow, Glasgow (United Kingdom); Bortoluzzi, D; Bosetti, P; Cristofolini, I [Dipartimento di Ingegneria Meccanica e Strutturale, Universita di Trento and INFN, Gruppo Collegato di Trento, Mesiano, Trento (Italy); Brandt, N [Astrium GmbH, 88039 Friedrichshafen (Germany); Cruise, M, E-mail: anneke.monsky@aei.mpg.d [Department of Physics and Astronomy, University of Birmingham, Birmingham (United Kingdom)

    2009-05-07

    The data analysis of the LISA Technology Package (LTP) will comprise a series of discrete experiments, each focusing on a particular noise measurement or characterization of the instrument in various operating modes. Each of these experiments must be analysed and planned in advance of the mission because the results of a given experiment will have an impact on those that follow. As such, a series of mock data challenges (MDCs) will be developed and carried out with the aim of preparing the analysis tools and optimizing the various planned analyses. The first of these MDCs (MDC1) is a simplified treatment of the dynamics along the axis joining the two test masses onboard LISA Pathfinder. The validation of the dynamical model by predicting the spectra of the interferometer output data is shown, a prediction for the data analysis is calculated and, finally, several simulated interferometer data sets are analysed and calibrated to equivalent out-of-loop test mass acceleration.

  6. Alternative opto-mechanical architectures for the LISA instrument

    Energy Technology Data Exchange (ETDEWEB)

    Weise, Dennis R; Marenaci, Pierangelo; Weimer, Peter; Schulte, Hans Reiner; Gath, Peter; Johann, Ulrich, E-mail: dennis.weise@astrium.eads.ne [EADS Astrium GmbH, Claude-Dornier-Str., 88039 Friedrichshafen (Germany)

    2009-03-01

    As part of the on-going LISA Mission Formulation study under ESA contract, EADS Astrium has recently suggested and investigated a variety of novel LISA payload architectures utilizing so-called 'In-Field Pointing' for accommodation of seasonal constellation dynamics. Here, the annual variation in the angle between the interferometer arms of roughly +-1 deg. is compensated by steering the lines of sight of the individual telescopes with a small actuated mirror located in an intermediate pupil plane inside the telescopes. This introduces a certain flexibility for the overall payload configuration and allows for very compact designs. In particular, it enables a 'single active proof mass' mode with a true cold redundancy between a nominal and a backup GRS system on board each spacecraft, and thus enhances mission robustness.

  7. Recent progress at NASA in LISA formulation and technology development

    International Nuclear Information System (INIS)

    Stebbins, R T

    2008-01-01

    Over the last year, the NASA half of the joint LISA project has focused its efforts on responding to a major review, and advancing the formulation and technology development of the mission. The NAS/NRC Beyond Einstein program assessment review will be described, including the outcome. The basis of the LISA science requirements has changed from detection determined by integrated signal-to-noise ratio to observation determined by uncertainty in the estimation of astrophysical source parameters. The NASA team has further defined the spacecraft bus design, participated in many design trade studies and advanced the requirements flow down and the associated current best estimates of performance. Recent progress in technology development is also summarized

  8. Report on the second Mock LISA data challenge

    International Nuclear Information System (INIS)

    Babak, Stanislav; Porter, Edward K; Baker, John G; Benacquista, Matthew J; Cornish, Neil J; Littenberg, Tyson B; Crowder, Jeff; Cutler, Curt; Vallisneri, Michele; Larson, Shane L; Vecchio, Alberto; Auger, Gerard; Barack, Leor; Blaut, Arkadiusz; Bloomer, Ed; Clark, James; Brown, Duncan A; Fairhurst, Stephen; Christensen, Nelson; Gair, Jonathan R

    2008-01-01

    The Mock LISA data challenges are a program to demonstrate LISA data-analysis capabilities and to encourage their development. Each round of challenges consists of several data sets containing simulated instrument noise and gravitational waves from sources of undisclosed parameters. Participants are asked to analyze the data sets and report the maximum information about the source parameters. The challenges are being released in rounds of increasing complexity and realism: here we present the results of Challenge 2, issued in Jan 2007, which successfully demonstrated the recovery of signals from nonspinning supermassive-black-hole binaries with optimal SNRs between ∼10 and 2000, from ∼20 000 overlapping galactic white-dwarf binaries (among a realistically distributed population of 26 million), and from the extreme-mass-ratio inspirals of compact objects into central galactic black holes with optimal SNRs ∼100

  9. Possible LISA follow-on mission scientific objectives

    International Nuclear Information System (INIS)

    Bender, Peter L; Begelman, Mitchell C; Gair, Jonathan R

    2013-01-01

    A major objective that has been suggested for a follow-on mission to a Laser Interferometer Space Antenna (LISA)-type mission is to investigate more completely how intermediate mass black holes were formed and grew in the early universe, before they evolved into the much more massive black holes at the centers of many galaxies today. The actual design of such a follow-on mission will of course depend on what is observed by a LISA-type mission, such as the recently modified proposal for an evolved LISA mission, with the interferometer arm lengths between spacecraft reduced from 5 million to 1 million km. However, the sensitivity goals of a follow-on mission are likely to be influenced strongly by the desire to be able to see mergers of 10 M ⊙ black holes with roughly 3000 M ⊙ or larger intermediate mass black holes out to as large redshifts as possible. Approximate calculations of the expected signal-to-noise have been made for a possible LISA follow-on mission that was suggested about eight years ago (Bender and Begelman 2005 Trends in Space Science and Cosmic Vision 2020 (Noordwijk: ESA Publications Division) pp 33–38), and was called the Advanced Laser Interferometer Antenna. Based on the calculations, it appears that detections out to a redshift of 10 would be possible for 10 M ⊙ black holes spiraling into perhaps 5000 M ⊙ or larger intermediate mass black holes if the extragalactic gravitational wave background due to close white dwarf binaries is in the currently estimated range. (paper)

  10. Cosmological Backgrounds of Gravitational Waves and eLISA

    OpenAIRE

    Dufaux, Jean-Francois

    2012-01-01

    We review cosmological backgrounds of gravitational waves with a particular attention to the scientific potential of the eLISA/NGO mission. After an overview of cosmological backgrounds and detectors, we consider different cosmological sources that could lead to an observable signal. We then study the backgrounds produced by first-order phase transitions and networks of cosmic strings, assessing the prospects for their detection.

  11. Implementation of time-delay interferometry for LISA

    International Nuclear Information System (INIS)

    Tinto, Massimo; Shaddock, Daniel A.; Sylvestre, Julien; Armstrong, J.W.

    2003-01-01

    We discuss the baseline optical configuration for the Laser Interferometer Space Antenna (LISA) mission, in which the lasers are not free-running, but rather one of them is used as the main frequency reference generator (the master) and the remaining five as slaves, these being phase-locked to the master (the master-slave configuration). Under the condition that the frequency fluctuations due to the optical transponders can be made negligible with respect to the secondary LISA noise sources (mainly proof-mass and shot noises), we show that the entire space of interferometric combinations LISA can generate when operated with six independent lasers (the one-way method) can also be constructed with the master-slave system design. The corresponding hardware trade-off analysis for these two optical designs is presented, which indicates that the two sets of systems needed for implementing the one-way method, and the master-slave configuration, are essentially identical. Either operational mode could therefore be implemented without major implications on the hardware configuration. We then derive the required accuracies of armlength knowledge, time synchronization of the onboard clocks, sampling times and time-shifts needed for effectively implementing time-delay interferometry for LISA. We find that an armlength accuracy of about 16 meters, a synchronization accuracy of about 50 ns, and the time jitter due to a presently existing space qualified clock will allow the suppression of the frequency fluctuations of the lasers below to the level identified by the secondary noise sources. A new procedure for sampling the data in such a way to avoid the problem of having time shifts that are not integer multiples of the sampling time is also introduced, addressing one of the concerns about the implementation of time-delay interferometry

  12. UV-LED-based charge control for LISA

    Science.gov (United States)

    Olatunde, Taiwo; Shelley, Ryan; Chilton, Andrew; Ciani, Giacomo; Mueller, Guido; Conklin, John

    2014-03-01

    The test masses inside the LISA gravitational reference sensors (GRS) must maintain almost pure geodesic motion for gravitational waves to be successfully detected. The residual accelerations have to stay below 3fm/s2/rtHz at all frequencies between 0.1 and 3 mHz. One of the well known noise sources is associated with the charges on the test masses which couple to stray electrical potentials and external electro-magnetic fields. The LISA pathfinder (LPF) will use Hg-discharge lamps emitting mostly around 253 nm to discharge the test masses via photoemission in its 2015/16 flight. A future LISA mission launched around 2030 will likely replace the lamps with newer UV-LEDs. UV-LEDs have a lower mass, a better power efficiency, and are smaller than their Hg counterparts. Furthermore, the latest generation produces light at 240 nm, with energy well above the work function of pure gold. I will describe a preliminary design for effective charge control through photoelectric effect by using these LEDs. The effectiveness of this method is verified by taking Quantum Efficiency (QE) measurements which relate the number of electrons emitted to the number of photons incident on the Au test mass surface. This presentation addresses our initial results and future plans which includes implementation and testing in the UF torsion pendulum and space-qualification in a small satellite mission which will launch in the summer of 2014, through a collaboration with Stanford, KACST, and NASA Ames Research Center.

  13. Nested sampling as a tool for LISA data analysis

    International Nuclear Information System (INIS)

    Gair, Jonathan R; Feroz, Farhan; Graff, Philip; Hobson, Michael P; Babak, Stanislav; Petiteau, Antoine; Porter, Edward K

    2010-01-01

    Nested sampling is a technique for efficiently computing the probability of a data set under a particular hypothesis, also called the Bayesian Evidence or Marginal Likelihood, and for evaluating the posterior. MULTINEST is a multi-modal nested sampling algorithm which has been designed to efficiently explore and characterize posterior probability surfaces containing multiple secondary solutions. We have applied the MULTINEST algorithm to a number of problems in gravitational wave data analysis. In this article, we describe the algorithm and present results for several applications of the algorithm to analysis of mock LISA data. We summarise recently published results for a test case in which we searched for two non-spinning black hole binary merger signals in simulated LISA data. We also describe results obtained with MULTINEST in the most recent round of the Mock LISA Data Challenge (MLDC), in which the algorithm was used to search for and characterise both spinning supermassive black hole binary inspirals and bursts from cosmic string cusps. In all these applications, the algorithm found the correct number of signals and efficiently recovered the posterior probability distribution. Moreover, in most cases the waveform corresponding to the best a-posteriori parameters had an overlap in excess of 99% with the true signal.

  14. Nested sampling as a tool for LISA data analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gair, Jonathan R [Institute of Astronomy, Madingley Road, CB3 0HA, Cambridge (United Kingdom); Feroz, Farhan; Graff, Philip; Hobson, Michael P [Astrophysics Group, Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Babak, Stanislav; Petiteau, Antoine [Max-Planck-Institut fuer Gravitationsphysik, Am Muehlenberg 1, 14476, Potsdam (Germany); Porter, Edward K, E-mail: jgair@ast.cam.ac.u [APC, UMR 7164, Universite Paris 7 Denis Diderot, 10, rue Alice Domon et Leonie Duquet, 75205 Paris Cedex 13 (France)

    2010-05-01

    Nested sampling is a technique for efficiently computing the probability of a data set under a particular hypothesis, also called the Bayesian Evidence or Marginal Likelihood, and for evaluating the posterior. MULTINEST is a multi-modal nested sampling algorithm which has been designed to efficiently explore and characterize posterior probability surfaces containing multiple secondary solutions. We have applied the MULTINEST algorithm to a number of problems in gravitational wave data analysis. In this article, we describe the algorithm and present results for several applications of the algorithm to analysis of mock LISA data. We summarise recently published results for a test case in which we searched for two non-spinning black hole binary merger signals in simulated LISA data. We also describe results obtained with MULTINEST in the most recent round of the Mock LISA Data Challenge (MLDC), in which the algorithm was used to search for and characterise both spinning supermassive black hole binary inspirals and bursts from cosmic string cusps. In all these applications, the algorithm found the correct number of signals and efficiently recovered the posterior probability distribution. Moreover, in most cases the waveform corresponding to the best a-posteriori parameters had an overlap in excess of 99% with the true signal.

  15. Theory and modelling of the magnetic field measurement in LISA PathFinder

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Aguilo, M; Garcia-Berro, E [Departament de Fisica Aplicada, Universitat Politecnica de Catalunya, c/Esteve Terrades, 5, 08860 Castelldefels (Spain); Lobo, A, E-mail: marc.diaz.aguilo@fa.upc.ed [Institut d' Estudis Espacials de Catalunya, c/Gran Capita 2-4, Edif. Nexus 104, 08034 Barcelona (Spain)

    2010-02-07

    The magnetic diagnostics subsystem of the LISA Technology Package (LTP) on board the LISA PathFinder (LPF) spacecraft includes a set of four tri-axial fluxgate magnetometers, intended to measure with high precision the magnetic field at their respective positions. However, their readouts do not provide a direct measurement of the magnetic field at the positions of the test masses, and hence an interpolation method must be designed and implemented to obtain the values of the magnetic field at these positions. However, such an interpolation process faces serious difficulties. Indeed, the size of the interpolation region is excessive for a linear interpolation to be reliable while, on the other hand, the number of magnetometer channels do not provide sufficient data to go beyond the linear approximation. We describe an alternative method to address this issue, by means of neural network algorithms. The key point in this approach is the ability of neural networks to learn from suitable training data representing the behaviour of the magnetic field. Despite the relatively large distance between the test masses and the magnetometers, and the insufficient number of data channels, we find that our artificial neural network algorithm is able to reduce the estimation errors of the field and gradient down to levels below 10%, a quite satisfactory result. Learning efficiency can be best improved by making use of data obtained in on-ground measurements prior to mission launch in all relevant satellite locations and in real operation conditions. Reliable information on that appears to be essential for a meaningful assessment of magnetic noise in the LTP.

  16. Theory and modelling of the magnetic field measurement in LISA PathFinder

    International Nuclear Information System (INIS)

    Diaz-Aguilo, M; Garcia-Berro, E; Lobo, A

    2010-01-01

    The magnetic diagnostics subsystem of the LISA Technology Package (LTP) on board the LISA PathFinder (LPF) spacecraft includes a set of four tri-axial fluxgate magnetometers, intended to measure with high precision the magnetic field at their respective positions. However, their readouts do not provide a direct measurement of the magnetic field at the positions of the test masses, and hence an interpolation method must be designed and implemented to obtain the values of the magnetic field at these positions. However, such an interpolation process faces serious difficulties. Indeed, the size of the interpolation region is excessive for a linear interpolation to be reliable while, on the other hand, the number of magnetometer channels do not provide sufficient data to go beyond the linear approximation. We describe an alternative method to address this issue, by means of neural network algorithms. The key point in this approach is the ability of neural networks to learn from suitable training data representing the behaviour of the magnetic field. Despite the relatively large distance between the test masses and the magnetometers, and the insufficient number of data channels, we find that our artificial neural network algorithm is able to reduce the estimation errors of the field and gradient down to levels below 10%, a quite satisfactory result. Learning efficiency can be best improved by making use of data obtained in on-ground measurements prior to mission launch in all relevant satellite locations and in real operation conditions. Reliable information on that appears to be essential for a meaningful assessment of magnetic noise in the LTP.

  17. Algebraic approach to time-delay data analysis for LISA

    International Nuclear Information System (INIS)

    Dhurandhar, S.V.; Nayak, K. Rajesh; Vinet, J.-Y.

    2002-01-01

    Cancellation of laser frequency noise in interferometers is crucial for attaining the requisite sensitivity of the triangular three-spacecraft LISA configuration. Raw laser noise is several orders of magnitude above the other noises and thus it is essential to bring it down to the level of other noises such as shot, acceleration, etc. Since it is impossible to maintain equal distances between spacecrafts, laser noise cancellation must be achieved by appropriately combining the six beams with appropriate time delays. It has been shown in several recent papers that such combinations are possible. In this paper, we present a rigorous and systematic formalism based on algebraic geometrical methods involving computational commutative algebra, which generates in principle all the data combinations canceling the laser frequency noise. The relevant data combinations form the first module of syzygies, as it is called in the literature of algebraic geometry. The module is over a polynomial ring in three variables, the three variables corresponding to the three time delays around the LISA triangle. Specifically, we list several sets of generators for the module whose linear combinations with polynomial coefficients generate the entire module. We find that this formalism can also be extended in a straightforward way to cancel Doppler shifts due to optical bench motions. The two modules are in fact isomorphic. We use our formalism to obtain the transfer functions for the six beams and for the generators. We specifically investigate monochromatic gravitational wave sources in the LISA band and carry out the maximization over linear combinations of the generators of the signal-to-noise ratios with the frequency and source direction angles as parameters

  18. GCR flux 9-day variations with LISA Pathfinder

    International Nuclear Information System (INIS)

    Grimani, C; Benella, S; Fabi, M; Finetti, N; Telloni, D

    2017-01-01

    Galactic cosmic-ray (GCR) energy spectra in the heliosphere vary on the basis of the level of solar activity, the status of solar polarity and interplanetary transient magnetic structures of solar origin. A high counting rate particle detector (PD) aboard LISA Pathfinder (LPF) allows for the measurement of galactic cosmic-ray and solar energetic particle (SEP) integral fluxes at energies > 70 MeV n −1 up to 6500 counts s −1 . Data are gathered with a sampling time of 15 s. A study of GCR flux depressions associated with the third harmonic of the Sun rotation period (∼ 9 days) is presented here. (paper)

  19. Energy transport in mirror machine LISA at electron cyclotron resonance

    International Nuclear Information System (INIS)

    Cunha Rapozo, C. da; Serbeto, A.; Torres-Silva, H.

    1993-01-01

    It is shown that a classical transport calculation is adequate to predict the steady state temperature of the RF produced plasma in LISA machine for both large and small resonant volumes. Temperature anisotropy ranging from 55 to 305 was found which was larger for small resonant volume, and the temperature relaxation was larger at large resonant one. This agrees with the fact that there is a Coulomb relaxation ν c which is proportional to T e -3/2 . It is also shown that the fitting parameter alpha is larger for large resonant volume than for small resonant one. (L.C.J.A.)

  20. A study on the radionuclide migration by means of the code LISA

    International Nuclear Information System (INIS)

    Frenquellucci, F.; Deserti, M.

    1989-01-01

    LISA code (Long Term Isolation Safety Assessment) has been developed by J.R.C. EUROATOM Ispra (Radiochemistry Division) and it's utilized in order to study migration of radionuclides through porous media. Aim of the present work is to analyze LISA's input and output files. A brief description of the code is also performed. As LISA is a research and in development code, its structure is rather complex and an exhaustive description of input/output files is helpful for the user. Version 3 of LISA code, loaded on ENEA's IBM 3090, is avaylable by ENEA-VEL Bologna

  1. Prospects of eLISA for Detecting Galactic Binary Black Holes Similar to GW150914

    OpenAIRE

    Seto, Naoki

    2016-01-01

    We discuss the prospects of eLISA for detecting gravitational waves (GWs) from Galactic binary black holes (BBHs) similar to GW150914. For a comoving merger rate that is consistent with current observation, eLISA is likely to identify at least one BBH with a sufficient signal-to-noise ratio. In addition, eLISA has a potential to measure the eccentricity of the BBH as small as $e\\sim 0.02$, corresponding to the residual value $e\\sim 10^{-6}$ at 10Hz. Therefore, eLISA could provide us with a cr...

  2. Towards an improved magnetic diagnostic system for LISA

    International Nuclear Information System (INIS)

    Mateos, I; Lobo, A; Sanjuan, J; Ramos-Castro, J; Nofrarias, M

    2009-01-01

    The current design, and material implementation of the magnetic field sensing in the LISA Technology Package (LTP) on board LISA Pathfinder (LPF), is based on a set of 4 high-precision 3-axis fluxgate magnetometers. In order to avoid magnetic disturbances on the LTP proof masses (TM 's), originated by the sensors themselves, these are placed somewhat far from the TM's, which results in partial field information losses. We are currently investigating alternative magnetic sensing techniques, based on AMR (Anisotropic Magnetoresistive) devices. These are much smaller in size than fluxgates, therefore a more numerous array can be thought of for flight. In addition, there is a chance that they may be attached closer to the TM's, thereby enhancing magnetic field sensing spacial resolution. Several issues need to be addressed, such as real sensitivity (including electronics noise) and set/reset trigger procedures. A brief overview about the stability of the magnetic fields and gradients generated in the LTP by means of the coil will also be given. This paper show the latest results of our research.

  3. Classifying LISA gravitational wave burst signals using Bayesian evidence

    International Nuclear Information System (INIS)

    Feroz, Farhan; Graff, Philip; Hobson, Michael P; Lasenby, Anthony; Gair, Jonathan R

    2010-01-01

    We consider the problem of characterization of burst sources detected by the Laser Interferometer Space Antenna (LISA) using the multi-modal nested sampling algorithm, MultiNest. We use MultiNest as a tool to search for modelled bursts from cosmic string cusps, and compute the Bayesian evidence associated with the cosmic string model. As an alternative burst model, we consider sine-Gaussian burst signals, and show how the evidence ratio can be used to choose between these two alternatives. We present results from an application of MultiNest to the last round of the Mock LISA Data Challenge, in which we were able to successfully detect and characterize all three of the cosmic string burst sources present in the release data set. We also present results of independent trials and show that MultiNest can detect cosmic string signals with signal-to-noise ratio (SNR) as low as ∼7 and sine-Gaussian signals with SNR as low as ∼8. In both cases, we show that the threshold at which the sources become detectable coincides with the SNR at which the evidence ratio begins to favour the correct model over the alternative.

  4. Disentangling the magnetic force noise contribution in LISA Pathfinder

    International Nuclear Information System (INIS)

    Armano, M; Audley, H; Born, M; Danzmann, K; Diepholz, I; Auger, G; Binetruy, P; Baird, J; Bortoluzzi, D; Brandt, N; Fitzsimons, E; Bursi, A; Caleno, M; Cavalleri, A; Cesarini, A; Dolesi, R; Ferroni, V; Cruise, M; Dunbar, N; Ferraioli, L

    2015-01-01

    Magnetically-induced forces on the inertial masses on-board LISA Pathfinder are expected to be one of the dominant contributions to the mission noise budget, accounting for up to 40%. The origin of this disturbance is the coupling of the residual magnetization and susceptibility of the test masses with the environmental magnetic field. In order to fully understand this important part of the noise model, a set of coils and magnetometers are integrated as a part of the diagnostics subsystem. During operations a sequence of magnetic excitations will be applied to precisely determine the coupling of the magnetic environment to the test mass displacement using the on-board magnetometers. Since no direct measurement of the magnetic field in the test mass position will be available, an extrapolation of the magnetic measurements to the test mass position will be carried out as a part of the data analysis activities. In this paper we show the first results on the magnetic experiments during an end- to-end LISA Pathfinder simulation, and we describe the methods under development to map the magnetic field on-board. (paper)

  5. Revised electrostatic model of the LISA Pathfinder inertial sensor

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, Nico [Astrium GmbH, 88039 Friedrichshafen (Germany); Fichter, Walter, E-mail: nico.brandt@astrium.eads.ne [iFR, Universitaet Stuttgart, Pfaffenwaldring 7a, 70569 Stuttgart (Germany)

    2009-03-01

    A comprehensive electrostatic finite-element (FE) analysis of the LISA Pathfinder Inertial Sensor (IS) has been carried out at Astrium GmbH. Starting with a detailed geometrical model of the IS housing and test mass (TM) flight units, FE results were derived from multiple analyses runs applying the Maxwell 3D field simulation software. The electrostatic forces and torques on the TM in 6DoF, as well as all non-negligible capacitances between the TM, the 18 electrodes, and the housing, have been extracted for different TM translations and rotations. The results of the FE analyses were expected to confirm the existing IS electrostatic model predictions used for performance analysis, simulations, and on-board algorithms. Major discrepancies were found, however, between the results and the model used so far. In general, FE results give considerably larger capacitance values than the equivalent infinite non-parallel plate estimates. In contrast, the FE derived forces and torques are in general significantly lower compared to the analytic IS electrostatic model predictions. In this paper, these results are discussed in detail and the reasons for the deviations are elaborated. Based on these results, an adapted analytic IS electrostatic model is proposed that reflects the electrostatic forces, torques, and stiffness values in the LISA Pathfinder IS significantly more accurate.

  6. Revised electrostatic model of the LISA Pathfinder inertial sensor

    International Nuclear Information System (INIS)

    Brandt, Nico; Fichter, Walter

    2009-01-01

    A comprehensive electrostatic finite-element (FE) analysis of the LISA Pathfinder Inertial Sensor (IS) has been carried out at Astrium GmbH. Starting with a detailed geometrical model of the IS housing and test mass (TM) flight units, FE results were derived from multiple analyses runs applying the Maxwell 3D field simulation software. The electrostatic forces and torques on the TM in 6DoF, as well as all non-negligible capacitances between the TM, the 18 electrodes, and the housing, have been extracted for different TM translations and rotations. The results of the FE analyses were expected to confirm the existing IS electrostatic model predictions used for performance analysis, simulations, and on-board algorithms. Major discrepancies were found, however, between the results and the model used so far. In general, FE results give considerably larger capacitance values than the equivalent infinite non-parallel plate estimates. In contrast, the FE derived forces and torques are in general significantly lower compared to the analytic IS electrostatic model predictions. In this paper, these results are discussed in detail and the reasons for the deviations are elaborated. Based on these results, an adapted analytic IS electrostatic model is proposed that reflects the electrostatic forces, torques, and stiffness values in the LISA Pathfinder IS significantly more accurate.

  7. T.D Lee and Lisa Randall visit ATLAS

    CERN Multimedia

    Pauline Gagnon

    Professor Tsung-Dao Lee, who received the Nobel Prize for Physics in 1957 for postulating that parity is not conserved in weak interactions, visited the ATLAS detector this month. He is seen here in the company of Peter Jenni, spokesperson for ATLAS. T.D. Lee is still very active at over 80, pursuing his theory work to this day. Professor Lisa Randall from Harvard University, the well-known theorist behind the Randall-Sundrum theory for extra dimensions, was also part of the group visiting the ATLAS detector. She is seen here with Fabiola Gianotti, deputy spokesperson for ATLAS. Lisa Randall's two initial papers have been quoted both more than 2500 times, making her the most cited theoretical physicist in the world in the last five years as of last autumn - a total of about 10,000 citations! One wonders here if Peter is pointing to a CP-violating graviton spotted in the ATLAS cavern... From left to right: Fabiola Gianotti, Gustaaf Brooijmans, convener of the ATLAS Exotics physics gro...

  8. White-dwarf-white-dwarf galactic background in the LISA data

    International Nuclear Information System (INIS)

    Edlund, Jeffrey A.; Tinto, Massimo; Krolak, Andrzej; Nelemans, Gijs

    2005-01-01

    LISA (Laser Interferometer Space Antenna) is a proposed space mission, which will use coherent laser beams exchanged between three remote spacecraft to detect and study low-frequency cosmic gravitational radiation. In the low part of its frequency band, the LISA strain sensitivity will be dominated by the incoherent superposition of hundreds of millions of gravitational wave signals radiated by inspiraling white-dwarf binaries present in our own Galaxy. In order to estimate the magnitude of the LISA response to this background, we have simulated a synthesized population that recently appeared in the literature. Our approach relies on entirely analytic expressions of the LISA time-delay interferometric responses to the gravitational radiation emitted by such systems, which allows us to implement a computationally efficient and accurate simulation of the background in the LISA data. We find the amplitude of the galactic white-dwarf binary background in the LISA data to be modulated in time, reaching a minimum equal to about twice that of the LISA noise for a period of about two months around the time when the Sun-LISA direction is roughly oriented towards the Autumn equinox. This suggests that, during this time period, LISA could search for other gravitational wave signals incoming from directions that are away from the galactic plane. Since the galactic white-dwarf background will be observed by LISA not as a stationary but rather as a cyclostationary random process with a period of 1 yr, we summarize the theory of cyclostationary random processes, present the corresponding generalized spectral method needed to characterize such process, and make a comparison between our analytic results and those obtained by applying our method to the simulated data. We find that, by measuring the generalized spectral components of the white-dwarf background, LISA will be able to infer properties of the distribution of the white-dwarf binary systems present in our Galaxy

  9. Beyond the Required LISA Free-Fall Performance: New LISA Pathfinder Results down to 20 μ Hz

    Science.gov (United States)

    Armano, M.; Audley, H.; Baird, J.; Binetruy, P.; Born, M.; Bortoluzzi, D.; Castelli, E.; Cavalleri, A.; Cesarini, A.; Cruise, A. M.; Danzmann, K.; de Deus Silva, M.; Diepholz, I.; Dixon, G.; Dolesi, R.; Ferraioli, L.; Ferroni, V.; Fitzsimons, E. D.; Freschi, M.; Gesa, L.; Gibert, F.; Giardini, D.; Giusteri, R.; Grimani, C.; Grzymisch, J.; Harrison, I.; Heinzel, G.; Hewitson, M.; Hollington, D.; Hoyland, D.; Hueller, M.; Inchauspé, H.; Jennrich, O.; Jetzer, P.; Karnesis, N.; Kaune, B.; Korsakova, N.; Killow, C. J.; Lobo, J. A.; Lloro, I.; Liu, L.; López-Zaragoza, J. P.; Maarschalkerweerd, R.; Mance, D.; Meshksar, N.; Martín, V.; Martin-Polo, L.; Martino, J.; Martin-Porqueras, F.; Mateos, I.; McNamara, P. W.; Mendes, J.; Mendes, L.; Nofrarias, M.; Paczkowski, S.; Perreur-Lloyd, M.; Petiteau, A.; Pivato, P.; Plagnol, E.; Ramos-Castro, J.; Reiche, J.; Robertson, D. I.; Rivas, F.; Russano, G.; Slutsky, J.; Sopuerta, C. F.; Sumner, T.; Texier, D.; Thorpe, J. I.; Vetrugno, D.; Vitale, S.; Wanner, G.; Ward, H.; Wass, P. J.; Weber, W. J.; Wissel, L.; Wittchen, A.; Zweifel, P.

    2018-02-01

    In the months since the publication of the first results, the noise performance of LISA Pathfinder has improved because of reduced Brownian noise due to the continued decrease in pressure around the test masses, from a better correction of noninertial effects, and from a better calibration of the electrostatic force actuation. In addition, the availability of numerous long noise measurement runs, during which no perturbation is purposely applied to the test masses, has allowed the measurement of noise with good statistics down to 20 μ Hz . The Letter presents the measured differential acceleration noise figure, which is at (1.74 ±0.01 ) fm s-2/√{Hz } above 2 mHz and (6 ±1 ) ×10 fm s-2/√{Hz } at 20 μ Hz , and discusses the physical sources for the measured noise. This performance provides an experimental benchmark demonstrating the ability to realize the low-frequency science potential of the LISA mission, recently selected by the European Space Agency.

  10. Probing the Universe with Gravitational Waves: the Laser Interferometer Space Antenna (LISA)

    NARCIS (Netherlands)

    Prince, T.A.; Binetruy, P.; Centrella, J.; Finn, L.; Hogan, C.; Nelemans, G.A.; Phinney, S.

    2007-01-01

    - For the LISA International Science Team: LISA is a joint NASA/ESA space mission designed to measure gravitational waves in the band from 0.1 mHz to 0.1 Hz, a band that is richly populated by strong sources of gravitational waves. Signals will come from a wider range of sources: massive black holes

  11. Control system design for the constellation acquisition phase of the LISA mission

    Energy Technology Data Exchange (ETDEWEB)

    Cirillo, Francesca; Gath, Peter F, E-mail: francesca.cirillo@astrium.eads.ne, E-mail: peter.gath@astrium.eads.ne [Astrium GmbH Satellites, 88039 Friedrichshafen (Germany)

    2009-03-01

    The objective of the constellation acquisition phase for the LISA mission is to establish the three laser links between the three spacecraft of the LISA constellation so that the interferometric measurements for the science experiment can commence. The laser beam acquisition for LISA is extremely challenging given the 5 million km distance between the spacecraft, the inherent limits of the attitude sensors accuracy, the orbit determination accuracy issues and the time required to phase-lock the incoming and outgoing laser signals. This paper presents the design of the control system for the acquisition phase of the LISA constellation: the acquisition operational procedure is outlined, guidance laws are defined together with the Gyro Mode attitude control principle, which implements a Kalman filter for disturbances rejection purposes. Constellation-wide non-linear simulations demonstrate that the LISA constellation acquisition phase is feasible by means of the proposed control strategy.

  12. Control system design for the constellation acquisition phase of the LISA mission

    International Nuclear Information System (INIS)

    Cirillo, Francesca; Gath, Peter F

    2009-01-01

    The objective of the constellation acquisition phase for the LISA mission is to establish the three laser links between the three spacecraft of the LISA constellation so that the interferometric measurements for the science experiment can commence. The laser beam acquisition for LISA is extremely challenging given the 5 million km distance between the spacecraft, the inherent limits of the attitude sensors accuracy, the orbit determination accuracy issues and the time required to phase-lock the incoming and outgoing laser signals. This paper presents the design of the control system for the acquisition phase of the LISA constellation: the acquisition operational procedure is outlined, guidance laws are defined together with the Gyro Mode attitude control principle, which implements a Kalman filter for disturbances rejection purposes. Constellation-wide non-linear simulations demonstrate that the LISA constellation acquisition phase is feasible by means of the proposed control strategy.

  13. Relativistic analysis of the LISA long range optical links

    International Nuclear Information System (INIS)

    Chauvineau, Bertrand; Regimbau, Tania; Vinet, Jean-Yves; Pireaux, Sophie

    2005-01-01

    The joint ESA/NASA LISA mission consists of three spacecraft on heliocentric orbits, flying in a triangular formation of 5 Mkm each side, linked by infrared optical beams. The aim of the mission is to detect gravitational waves in a low frequency band. For properly processing the scientific data, the propagation delays between spacecraft must be accurately known. We thus analyze the propagation of light between spacecraft in order to systematically derive the relativistic effects due to the static curvature of the Schwarzschild space-time in which the spacecraft are orbiting with time-varying light distances. In particular, our analysis allows us to evaluate rigorously the Sagnac effect, and the gravitational (Einstein) redshift

  14. LISA Pathfinder drag-free control and system implications

    International Nuclear Information System (INIS)

    Fichter, Walter; Gath, Peter; Vitale, Stefano; Bortoluzzi, Daniele

    2005-01-01

    The top-level requirement of the LISA Pathfinder mission is the verification of pure relative free fall between two test masses with an accuracy of about 3 x 10 -14 m s -2 Hz -1/2 in a measurement bandwidth between 1 mHz and 30 mHz. The drag-free control system is one of the key technology elements that shall be verified. Its design is strongly connected to the overall system and experimental design, in particular, via the following issues: the differential test mass motion and thus the science measurements depend on the control system; design constraints, such as negative stiffness of test masses and electrostatic actuation cross-talk, have an impact on science and control system performance; derived requirements for control system components, in particular, the micro-propulsion system, must be within reasonable and feasible limits. In this paper, the control design approach is outlined and the system-related issues are addressed

  15. The LISA Pathfinder interferometry-hardware and system testing

    Energy Technology Data Exchange (ETDEWEB)

    Audley, H; Danzmann, K; MarIn, A Garcia; Heinzel, G; Monsky, A; Nofrarias, M; Steier, F; Bogenstahl, J [Albert-Einstein-Institut, Max-Planck-Institut fuer Gravitationsphysik und Universitaet Hannover, 30167 Hannover (Germany); Gerardi, D; Gerndt, R; Hechenblaikner, G; Johann, U; Luetzow-Wentzky, P; Wand, V [EADS Astrium GmbH, Friedrichshafen (Germany); Antonucci, F [Dipartimento di Fisica, Universita di Trento and INFN, Gruppo Collegato di Trento, 38050 Povo, Trento (Italy); Armano, M [European Space Astronomy Centre, European Space Agency, Villanueva de la Canada, 28692 Madrid (Spain); Auger, G; Binetruy, P [APC UMR7164, Universite Paris Diderot, Paris (France); Benedetti, M [Dipartimento di Ingegneria dei Materiali e Tecnologie Industriali, Universita di Trento and INFN, Gruppo Collegato di Trento, Mesiano, Trento (Italy); Boatella, C, E-mail: antonio.garcia@aei.mpg.de [CNES, DCT/AQ/EC, 18 Avenue Edouard Belin, 31401 Toulouse, Cedex 9 (France)

    2011-05-07

    Preparations for the LISA Pathfinder mission have reached an exciting stage. Tests of the engineering model (EM) of the optical metrology system have recently been completed at the Albert Einstein Institute, Hannover, and flight model tests are now underway. Significantly, they represent the first complete integration and testing of the space-qualified hardware and are the first tests on an optical system level. The results and test procedures of these campaigns will be utilized directly in the ground-based flight hardware tests, and subsequently during in-flight operations. In addition, they allow valuable testing of the data analysis methods using the MATLAB-based LTP data analysis toolbox. This paper presents an overview of the results from the EM test campaign that was successfully completed in December 2009.

  16. Commissioning and operating experience with the LISA superconducting accelerator

    International Nuclear Information System (INIS)

    Castellano, M.; Ferrario, M.; Minestrini, M.; Patteri, P.; Tazzioli, F.; Kulinski, S.

    1996-06-01

    The commissioning of the LISA superconducting (SC) RF electron linac at INFN Frascati Laboratories has been concluded although, due to a change in program priorities, the full possibilities of the machine have not been exploited. In this report the authors illustrate the results achieved so far and the difficulties encountered in commissioning, with the hope that this material might be some of help to those who intend to start the enterprise of building a SC linac in a non specialized environment. The part concerning the SC system is particularly stressed, but a relevant attention is also devoted to the traditional room temperature injector, the proper setting of which is fundamental to achieving the high beam quality that such a machine allows

  17. Detecting white dwarf binaries in Mock LISA Data Challenge 3

    International Nuclear Information System (INIS)

    Blaut, A; Krolak, A; Babak, S

    2009-01-01

    We present a strategy for detecting gravitational wave signals from the Galactic white dwarf binaries in the Mock LISA Data Challenge 3 (MLDC3) and estimate their parameters. Our method is based on the matched filtering in the form of the F-statistic. We perform the search on three-dimensional space (sky coordinate and frequency of gravitational wave) below 3 mHz and include the fourth parameter (frequency derivative) at high frequencies. A template bank is used to search for the strongest signal in the data, then we remove it and repeat the search until we do not have signals in the data above a preselected threshold. For the template bank, we construct an optimal grid that realizes the best lattice covering with a constraint such that the nodes of the grid coincide with the Fourier frequencies. This enables the use of the fast Fourier transform algorithm to calculate the F-statistic.

  18. Strong lensing of gravitational waves as seen by LISA.

    Science.gov (United States)

    Sereno, M; Sesana, A; Bleuler, A; Jetzer, Ph; Volonteri, M; Begelman, M C

    2010-12-17

    We discuss strong gravitational lensing of gravitational waves from the merging of massive black hole binaries in the context of the LISA mission. Detection of multiple events would provide invaluable information on competing theories of gravity, evolution and formation of structures and, possibly, constraints on H0 and other cosmological parameters. Most of the optical depth for lensing is provided by intervening massive galactic halos, for which wave optics effects are negligible. Probabilities to observe multiple events are sizable for a broad range of formation histories. For the most optimistic models, up to ≲ 4 multiple events with a signal to noise ratio ≳ 8 are expected in a 5-year mission. Chances are significant even for conservative models with either light (≲ 60%) or heavy (≲ 40%) seeds. Because of lensing amplification, some intrinsically too faint signals are brought over threshold (≲ 2 per year).

  19. Interferometry for the LISA technology package (LTP) aboard SMART-2

    International Nuclear Information System (INIS)

    Heinzel, G; Braxmaier, C; Schilling, R; Ruediger, A; Robertson, D; Plate, M te; Wand, V; Arai, K; Johann, U; Danzmann, K

    2003-01-01

    The interferometer of the LISA technology package (LTP) on SMART-2 is needed to verify the performance of the gravitational sensors by monitoring the distance between two test masses with a noise level of 10 pm Hz -1/2 between 3 mHz and 30 mHz. It must continuously track the motion of the test mass distance while that distance changes by many μm with a speed of up to 20 μm s -1 , without losing track of the sign of the motion and without exerting any influence on the test masses that might lead to a motion above that level. As a result of a detailed comparison study, a heterodyne Mach-Zehnder interferometer was selected as the baseline for the SMART-2 mission. Its design and expected performance are described in this paper

  20. The effects of orbital motion on LISA time delay interferometry

    International Nuclear Information System (INIS)

    Cornish, Neil J; Hellings, Ronald W

    2003-01-01

    In an effort to eliminate laser phase noise in laser interferometer spaceborne gravitational wave detectors, several combinations of signals have been found that allow the laser noise to be cancelled out while gravitational wave signals remain. This process is called time delay interferometry (TDI). In the papers that defined the TDI variables, their performance was evaluated in the limit that the gravitational wave detector is fixed in space. However, the performance depends on certain symmetries in the armlengths that are available if the detector is fixed in space, but that will be broken in the actual rotating and flexing configuration produced by the LISA orbits. In this paper we investigate the performance of these TDI variables for the real LISA orbits. First, addressing the effects of rotation, we verify Daniel Shaddock's result that the Sagnac variables α (t), β (t) and γ (t) will not cancel out the laser phase noise, and we also find the same result for the symmetric Sagnac variable ζ (t). The loss of the latter variable would be particularly unfortunate since this variable also cancels out gravitational wave signal, allowing instrument noise in the detector to be isolated and measured. Fortunately, we have found a set of more complicated TDI variables, which we call Δ Sagnac variables, one of which accomplishes the same goal as ζ (t) to good accuracy. Finally, however, as we investigate the effects of the flexing of the detector arms due to non-circular orbital motion, we show that all variables, including the interferometer variables, X(t), Y(t) and Z(t), which survive the rotation-induced loss of direction symmetry, will not completely cancel laser phase noise when the armlengths are changing with time. This unavoidable problem will place a stringent requirement on laser stability of ∼5 Hz Hz -1/2

  1. THE LISA GRAVITATIONAL WAVE FOREGROUND: A STUDY OF DOUBLE WHITE DWARFS

    International Nuclear Information System (INIS)

    Ruiter, Ashley J.; Belczynski, Krzysztof; Benacquista, Matthew; Williams, Gabriel; Larson, Shane L.

    2010-01-01

    Double white dwarfs (WDs) are expected to be a source of confusion-limited noise for the future gravitational wave observatory LISA. In a specific frequency range, this 'foreground noise' is predicted to rise above the instrumental noise and hinder the detection of other types of signals, e.g., gravitational waves arising from stellar-mass objects inspiraling into massive black holes. In many previous studies, only detached populations of compact object binaries have been considered in estimating the LISA gravitational wave foreground signal. Here, we investigate the influence of compact object detached and Roche-Lobe overflow (RLOF) Galactic binaries on the shape and strength of the LISA signal. Since >99% of remnant binaries that have orbital periods within the LISA sensitivity range are WD binaries, we consider only these binaries when calculating the LISA signal. We find that the contribution of RLOF binaries to the foreground noise is negligible at low frequencies, but becomes significant at higher frequencies, pushing the frequency at which the foreground noise drops below the instrumental noise to >6 mHz. We find that it is important to consider the population of mass-transferring binaries in order to obtain an accurate assessment of the foreground noise on the LISA data stream. However, we estimate that there still exists a sizeable number (∼11,300) of Galactic double WD binaries that will have a signal-to-noise ratio >5, and thus will be potentially resolvable with LISA. We present the LISA gravitational wave signal from the Galactic population of WD binaries, show the most important formation channels contributing to the LISA disk and bulge populations, and discuss the implications of these new findings.

  2. Annual modulation of the galactic binary confusion noise background and LISA data analysis

    International Nuclear Information System (INIS)

    Seto, Naoki

    2004-01-01

    We study the anisotropies of the galactic confusion noise background and its effects on LISA data analysis. LISA has two data streams of gravitational wave signals relevant for the low frequency regime. Because of the anisotropies of the background, the matrix for their confusion noises has off-diagonal components and depends strongly on the orientation of the detector plane. We find that the sky-averaged confusion noise level √(S(f)) could change by a factor of 2 in 3 months and would be minimum when the orbital position of LISA is around either the spring or autumn equinox

  3. Science with the space-based interferometer LISA. IV: probing inflation with gravitational waves

    International Nuclear Information System (INIS)

    Bartolo, Nicola; Guzzetti, Maria Chiara; Liguori, Michele; Matarrese, Sabino

    2016-01-01

    We investigate the potential for the LISA space-based interferometer to detect the stochastic gravitational wave background produced from different mechanisms during inflation. Focusing on well-motivated scenarios, we study the resulting contributions from particle production during inflation, inflationary spectator fields with varying speed of sound, effective field theories of inflation with specific patterns of symmetry breaking and models leading to the formation of primordial black holes. The projected sensitivities of LISA are used in a model-independent way for various detector designs and configurations. We demonstrate that LISA is able to probe these well-motivated inflationary scenarios beyond the irreducible vacuum tensor modes expected from any inflationary background.

  4. Science with the space-based interferometer LISA. IV: Probing inflation with gravitational waves

    CERN Document Server

    Bartolo, Nicola; Domcke, Valerie; Figueroa, Daniel G.; Garcia-Bellido, Juan; Guzzetti, Maria Chiara; Liguori, Michele; Matarrese, Sabino; Peloso, Marco; Petiteau, Antoine; Ricciardone, Angelo; Sakellariadou, Mairi; Sorbo, Lorenzo; Tasinato, Gianmassimo

    2016-01-01

    We investigate the potential for the LISA space-based interferometer to detect the stochastic gravitational wave background produced from different mechanisms during inflation. Focusing on well-motivated scenarios, we study the resulting contributions from particle production during inflation, inflationary spectator fields with varying speed of sound, effective field theories of inflation with specific patterns of symmetry breaking and models leading to the formation of primordial black holes. The projected sensitivities of LISA are used in a model-independent way for various detector designs and configurations. We demonstrate that LISA is able to probe these well-motivated inflationary scenarios beyond the irreducible vacuum tensor modes expected from any inflationary background.

  5. Radiation pressure calibration and test mass reflectivities for LISA Pathfinder

    International Nuclear Information System (INIS)

    Korsakova, Natalia; Kaune, Brigitte

    2017-01-01

    This paper describes a series of experiments which were carried out during the main operations of LISA Pathfinder. These experiments were performed by modulating the power of the measurement and reference beams. In one series of experiments the beams were sequentially switched on and off. In the other series of experiments the powers of the beams were modulated within 0.1% and 1% of the constant power. These experiments use recordings of the total power measured on the photodiodes to infer the properties of the Optical Metrology System (OMS), such as reflectivities of the test masses and change of the photodiode efficiencies with time. In the first case the powers are back propagated from the different photodiodes to the same place on the optical bench to express the unknown quantities in the measurement with the complimentary photodiode measurements. They are combined in the way that the only unknown left is the test mass reflectivities. The second experiment compared two estimates of the force applied to the test masses due to the radiation pressure that appears because of the beam modulations. One estimate of the force is inferred from the measurements of the powers on the photodiodes and propagation of this measurement to the test masses. The other estimation of the force is done by calculating it from the change in the main scientific output of the instrument – differential displacement of the two test masses. (paper)

  6. Analog phase lock between two lasers at LISA power levels

    International Nuclear Information System (INIS)

    Diekmann, Christian; Steier, Frank; Sheard, Benjamin; Heinzel, Gerhard; Danzmann, Karsten

    2009-01-01

    This paper presents the implementation of an analog optical phase-locked-loop with an offset frequency of about 20MHz between two lasers, where the detected light powers were of the order of 31 pW and 200 μW. The goal of this setup was the design and characterization of a photodiode transimpedance amplifier for application in LISA. By application of a transimpedance amplifier designed to have low noise and low power consumption, the phase noise between the two lasers was a factor of two above the shot noise limit down to 60mHz. The achievable phase sensitivity depends ultimately on the available power of the highly attenuated master laser and on the input current noise of the transimpedance amplifier of the photodetector. The limiting noise source below 60mHz was the analog phase measurement system that was used in this experiment. A digital phase measurement system that is currently under development at the AEI will be used in the near future. Its application should improve the sensitivity.

  7. Analog phase lock between two lasers at LISA power levels

    Energy Technology Data Exchange (ETDEWEB)

    Diekmann, Christian; Steier, Frank; Sheard, Benjamin; Heinzel, Gerhard; Danzmann, Karsten, E-mail: Christian.Diekmann@aei.mpg.d [Max-Planck-Institute for Gravitational Physics, Callinstr. 38, D-30167 Hannover (Germany)

    2009-03-01

    This paper presents the implementation of an analog optical phase-locked-loop with an offset frequency of about 20MHz between two lasers, where the detected light powers were of the order of 31 pW and 200 muW. The goal of this setup was the design and characterization of a photodiode transimpedance amplifier for application in LISA. By application of a transimpedance amplifier designed to have low noise and low power consumption, the phase noise between the two lasers was a factor of two above the shot noise limit down to 60mHz. The achievable phase sensitivity depends ultimately on the available power of the highly attenuated master laser and on the input current noise of the transimpedance amplifier of the photodetector. The limiting noise source below 60mHz was the analog phase measurement system that was used in this experiment. A digital phase measurement system that is currently under development at the AEI will be used in the near future. Its application should improve the sensitivity.

  8. Radiation pressure calibration and test mass reflectivities for LISA Pathfinder

    Science.gov (United States)

    Korsakova, Natalia; Kaune, Brigitte; LPF Collaboration

    2017-05-01

    This paper describes a series of experiments which were carried out during the main operations of LISA Pathfinder. These experiments were performed by modulating the power of the measurement and reference beams. In one series of experiments the beams were sequentially switched on and off. In the other series of experiments the powers of the beams were modulated within 0.1% and 1% of the constant power. These experiments use recordings of the total power measured on the photodiodes to infer the properties of the Optical Metrology System (OMS), such as reflectivities of the test masses and change of the photodiode efficiencies with time. In the first case the powers are back propagated from the different photodiodes to the same place on the optical bench to express the unknown quantities in the measurement with the complimentary photodiode measurements. They are combined in the way that the only unknown left is the test mass reflectivities. The second experiment compared two estimates of the force applied to the test masses due to the radiation pressure that appears because of the beam modulations. One estimate of the force is inferred from the measurements of the powers on the photodiodes and propagation of this measurement to the test masses. The other estimation of the force is done by calculating it from the change in the main scientific output of the instrument - differential displacement of the two test masses.

  9. Planning for chemical disasters at Point Lisas, Trinidad and Tobago

    International Nuclear Information System (INIS)

    Mathur, M.N.

    1995-01-01

    No major chemical disaster has taken place so far in Trinidad and Tobago. Even so, in view of the numerous hazards that the various chemical handling plants deal with at Point Lisas, the country has to be prepared to deal with chemical disasters. The country's emergency preparedness plan for chemical disasters aims to localize the emergency, if possible, eliminate it and minimize the effects of the accident on people and property. The hazards of ammonia, hydrogen, chlorine, hydrocarbons and methanol release can have devastating effects on the workers and the residents in the vicinity of the plants. The Emergency Plan identifies an Emergency Co-ordinating Officer who would take command of the off-site activities and coordinate the activities of Works Management, Local Authority, Police, Fire Services, Defence Force, Health Authority and Factory Inspectorate. Resources of fire fighting, medical treatment, telecommunications, waste management and public education have to be enhanced immediately. In the long term a new fire station and a new county hospital have to be built, some housing settlements have to be phased out and non-essential staff relocated

  10. LISA Pathfinder: An important first step towards a space-based gravitational wave observatory

    Science.gov (United States)

    Thorpe, James

    2017-08-01

    ESA's LISA Pathfinder mission was launched on Dec 3rd, 2015 and completed earlier this Summer. During this relatively short mission, Pathfinder at its two science payloads, Europe's LISA Technology Package and NASA's Disturbance Reduction System, demonstrated several techniques and technologies that enable development of a future space-based gravitational wave observatory. Most notably, Pathfinder demonstrated that the technique of drag-free flight could be utilized to place a test mass in near-perfect free-fall, with residual accelerations at the femto-g level in the milliHertz band. Additionally, technologies such as precision bonded optical structures for metrology, micropropulsion systems, and non-contact charge control, were successfully tested, retiring risk for LISA. In this talk, I will present an overview of Pathfinder's results to date and some perspective on how this success will be leveraged into realizing LISA.

  11. Report on the first round of the Mock LISA Data Challenges

    International Nuclear Information System (INIS)

    Arnaud, K A; Auger, G; Babak, S

    2007-01-01

    The Mock LISA Data Challenges (MLDCs) have the dual purpose of fostering the development of LISA data analysis tools and capabilities, and demonstrating the technical readiness already achieved by the gravitational-wave community in distilling a rich science payoff from the LISA data output. The first round of MLDCs has just been completed: nine challenges consisting of data sets containing simulated gravitational-wave signals produced either by galactic binaries or massive black hole binaries embedded in simulated LISA instrumental noise were released in June 2006 with deadline for submission of results at the beginning of December 2006. Ten groups have participated in this first round of challenges. All of the challenges had at least one entry which successfully characterized the signal to better than 95% when assessed via a correlation with phasing ambiguities accounted for. Here, we describe the challenges, summarize the results and provide a first critical assessment of the entries

  12. Stellar binary black holes in the LISA band: a new class of standard sirens

    Science.gov (United States)

    Del Pozzo, Walter; Sesana, Alberto; Klein, Antoine

    2018-04-01

    The recent Advanced LIGO detections of coalescing black hole binaries (BHBs) imply a large population of such systems emitting at milli-Hz frequencies, accessible to the Laser Interferometer Space Antenna (LISA). We show that these systems provide a new class of cosmological standard sirens. Direct LISA luminosity distance - Dl - measurements, combined with the inhomogeneous redshift - z - distribution of possible host galaxies provide an effective way to populate the Dl-z diagram at z arm-length, respectively.

  13. LISA extreme-mass-ratio inspiral events as probes of the black hole mass function

    International Nuclear Information System (INIS)

    Gair, Jonathan R.; Tang, Christopher; Volonteri, Marta

    2010-01-01

    One of the sources of gravitational waves for the proposed space-based gravitational wave detector, the Laser Interferometer Space Antenna (LISA), are the inspirals of compact objects into supermassive black holes in the centers of galaxies--extreme-mass-ratio inspirals (EMRIs). Using LISA observations, we will be able to measure the parameters of each EMRI system detected to very high precision. However, the statistics of the set of EMRI events observed by LISA will be more important in constraining astrophysical models than extremely precise measurements for individual systems. The black holes to which LISA is most sensitive are in a mass range that is difficult to probe using other techniques, so LISA provides an almost unique window onto these objects. In this paper we explore, using Bayesian techniques, the constraints that LISA EMRI observations can place on the mass function of black holes at low redshift. We describe a general framework for approaching inference of this type--using multiple observations in combination to constrain a parametrized source population. Assuming that the scaling of the EMRI rate with the black-hole mass is known and taking a black-hole distribution given by a simple power law, dn/dlnM=A 0 (M/M * ) α 0 , we find that LISA could measure the parameters to a precision of Δ(lnA 0 )∼0.08, and Δ(α 0 )∼0.03 for a reference model that predicts ∼1000 events. Even with as few as 10 events, LISA should constrain the slope to a precision ∼0.3, which is the current level of observational uncertainty in the low-mass slope of the black-hole mass function. We also consider a model in which A 0 and α 0 evolve with redshift, but find that EMRI observations alone do not have much power to probe such an evolution.

  14. Constraining stellar binary black hole formation scenarios with eLISA eccentricity measurements

    OpenAIRE

    Nishizawa, Atsushi; Sesana, Alberto; Berti, Emanuele; Klein, Antoine

    2016-01-01

    A space-based interferometer such as eLISA could observe few to few thousands progenitors of black hole binaries (BHBs) similar to those recently detected by Advanced LIGO. Gravitational radiation circularizes the orbit during inspiral, but some BHBs retain a measurable eccentricity at the low frequencies where eLISA is most sensitive. The eccentricity of a BHB carries precious information about its formation channel: BHBs formed in the field, in globular clusters, or close to a massive black...

  15. Optimal statistic for detecting gravitational wave signals from binary inspirals with LISA

    CERN Document Server

    Rogan, A

    2004-01-01

    A binary compact object early in its inspiral phase will be picked up by its nearly monochromatic gravitational radiation by LISA. But even this innocuous appearing candidate poses interesting detection challenges. The data that will be scanned for such sources will be a set of three functions of LISA's twelve data streams obtained through time-delay interferometry, which is necessary to cancel the noise contributions from laser-frequency fluctuations and optical-bench motions to these data streams. We call these three functions pseudo-detectors. The sensitivity of any pseudo-detector to a given sky position is a function of LISA's orbital position. Moreover, at a given point in LISA's orbit, each pseudo-detector has a different sensitivity to the same sky position. In this work, we obtain the optimal statistic for detecting gravitational wave signals, such as from compact binaries early in their inspiral stage, in LISA data. We also present how the sensitivity of LISA, defined by this optimal statistic, vari...

  16. Constraining stellar binary black hole formation scenarios with eLISA eccentricity measurements

    Science.gov (United States)

    Nishizawa, Atsushi; Sesana, Alberto; Berti, Emanuele; Klein, Antoine

    2017-03-01

    A space-based interferometer such as the evolved Laser Interferometer Space Antenna (eLISA) could observe a few to a few thousands of progenitors of black hole binaries (BHBs) similar to those recently detected by Advanced LIGO. Gravitational radiation circularizes the orbit during inspiral, but some BHBs retain a measurable eccentricity at the low frequencies where eLISA is the most sensitive. The eccentricity of a BHB carries precious information about its formation channel: BHBs formed in the field, in globular clusters, or close to a massive black hole (MBH) have distinct eccentricity distributions in the eLISA band. We generate mock eLISA observations, folding in measurement errors, and using a Bayesian model selection, we study whether eLISA measurements can identify the BHB formation channel. We find that a handful of observations would suffice to tell whether BHBs were formed in the gravitational field of an MBH. Conversely, several tens of observations are needed to tell apart field formation from globular cluster formation. A 5-yr eLISA mission with the longest possible armlength is desirable to shed light on BHB formation scenarios.

  17. Quantitative analysis of LISA pathfinder test-mass noise

    International Nuclear Information System (INIS)

    Ferraioli, Luigi; Congedo, Giuseppe; Hueller, Mauro; Vitale, Stefano; Hewitson, Martin; Nofrarias, Miquel; Armano, Michele

    2011-01-01

    LISA Pathfinder (LPF) is a mission aiming to test the critical technology for the forthcoming space-based gravitational-wave detectors. The main scientific objective of the LPF mission is to demonstrate test masses free falling with residual accelerations below 3x10 -14 m s -2 /√(Hz) at 1 mHz. Reaching such an ambitious target will require a significant amount of system optimization and characterization, which will in turn require accurate and quantitative noise analysis procedures. In this paper, we discuss two main problems associated with the analysis of the data from LPF: i) excess noise detection and ii) noise parameter identification. The mission is focused on the low-frequency region ([0.1, 10] mHz) of the available signal spectrum. In such a region, the signal is dominated by the force noise acting on test masses. At the same time, the mission duration is limited to 90 days and typical data segments will be 24 hours in length. Considering those constraints, noise analysis is expected to deal with a limited amount of non-Gaussian data, since the spectrum statistics will be far from Gaussian and the lowest available frequency is limited by the data length. In this paper, we analyze the details of the expected statistics for spectral data and develop two suitable excess noise estimators. One is based on the statistical properties of the integrated spectrum, the other is based on the Kolmogorov-Smirnov test. The sensitivity of the estimators is discussed theoretically for independent data, then the algorithms are tested on LPF synthetic data. The test on realistic LPF data allows the effect of spectral data correlations on the efficiency of the different noise excess estimators to be highlighted. It also reveals the versatility of the Kolmogorov-Smirnov approach, which can be adapted to provide reasonable results on correlated data from a modified version of the standard equations for the inversion of the test statistic. Closely related to excess noise

  18. Verification of time-delay interferometry techniques using the University of Florida LISA interferometry simulator

    Energy Technology Data Exchange (ETDEWEB)

    Mitryk, Shawn J; Wand, Vinzenz; Mueller, Guido, E-mail: smitryk@phys.ufl.ed, E-mail: mueller@phys.ufl.ed [Department of Physics, University of Florida, PO Box 118440, Gainesville, FL 32611-8440 (United States)

    2010-04-21

    Laser Interferometer Space Antenna (LISA) is a cooperative NASA/ESA mission proposed to directly measure gravitational waves (GW) in the frequency range from 30 muHz to 1 Hz with an optimal strain sensitivity of 10{sup -21}/sq root(Hz) at 3 mHz. LISA will utilize a modified Michelson interferometer to measure length changes of 40 pm/sq root(Hz) between drag-free proof masses located on three separate spacecraft (SC) separated by a distance of 5 Gm. The University of Florida has developed a hardware-in-the-loop simulator of the LISA constellation to verify the laser noise cancellation technique known as time-delay interferometry (TDI). We replicate the frequency stabilization of the laser on the local SC and the phase-locking of the lasers on the far SC. The laser photodetector beatnotes are electronically delayed, Doppler shifted and applied with a mock GW signal to simulate the laser link between the SC. The beatnotes are also measured with a LISA-like phasemeter and the data are used to extract the laser phase and residual phase-lock loop noise in post-processing through TDI. This uncovers the GW modulation signal buried under the laser noise. The results are then compared to the requirements defined by the LISA science collaboration.

  19. LISA Pathfinder test-mass charging during galactic cosmic-ray flux short-term variations

    Science.gov (United States)

    Grimani, C.; Fabi, M.; Lobo, A.; Mateos, I.; Telloni, D.

    2015-02-01

    Metal free-floating test masses aboard the future interferometers devoted to gravitational wave detection in space are charged by galactic and solar cosmic rays with energies \\gt 100 MeV/n. This process represents one of the main sources of noise in the lowest frequency band (\\lt 10-3 Hz) of these experiments. We study here the charging of the LISA Pathfinder (LISA-PF) gold-platinum test masses due to galactic cosmic-ray (GCR) protons and helium nuclei with the Fluka Monte Carlo toolkit. Projections of the energy spectra of GCRs during the LISA-PF operations in 2015 are considered. This work was carried out on the basis of the solar activity level and solar polarity epoch expected for LISA-PF. The effects of GCR short-term variations are evaluated here for the first time. Classical Forbush decreases, GCR variations induced by the Sun rotation, and fluctuations in the LISA-PF frequency bandwidth are discussed.

  20. Sensing and actuation system for the University of Florida Torsion Pendulum for LISA

    Science.gov (United States)

    Chilton, Andrew; Shelley, Ryan; Olatunde, Taiwo; Ciani, Giacomo; Conklin, John; Mueller, Guido

    2014-03-01

    Space-based gravitational wave detectors like LISA are a necessity for understanding the low-frequency portion of the gravitational universe. They use test masses (TMs) which are separated by Gm and are in free fall inside their respective spacecraft. Their relative distance is monitored with laser interferometry at the pm/rtHz level in the LISA band, ranging from 0.1 to 100 mHz. Each TM is enclosed in a housing that provides isolation, capacitive sensing, and electrostatic actuation capabilities. The electronics must both be sensitive at the 1 nm/rtHz level and not induce residual acceleration noise above the requirement for LISA Pathfinder (3*10-15 m/sec2Hz1/2at 3 mHz). Testing and developing this technology is one of the roles of the University of Florida Torsion Pendulum, the only US testbed for LISA-like gravitational reference sensor technology. Our implementation of the sensing system functions by biasing our hollow LISA-like TMs with a 100 kHz sine wave and coupling a pair surrounding electrodes as capacitors to a pair of preamps and a differential amplifier; all other processing is done digitally. Here we report on the design of, implementation of, and preliminary results from the UF Torsion Pendulum.

  1. Reducing tilt-to-length coupling for the LISA test mass interferometer

    Science.gov (United States)

    Tröbs, M.; Schuster, S.; Lieser, M.; Zwetz, M.; Chwalla, M.; Danzmann, K.; Fernández Barránco, G.; Fitzsimons, E. D.; Gerberding, O.; Heinzel, G.; Killow, C. J.; Perreur-Lloyd, M.; Robertson, D. I.; Schwarze, T. S.; Wanner, G.; Ward, H.

    2018-05-01

    Objects sensed by laser interferometers are usually not stable in position or orientation. This angular instability can lead to a coupling of angular tilt to apparent longitudinal displacement—tilt-to-length coupling (TTL). In LISA this is a potential noise source for both the test mass interferometer and the long-arm interferometer. We have experimentally investigated TTL coupling in a setup representative for the LISA test mass interferometer and used this system to characterise two different imaging systems (a two-lens design and a four-lens design) both designed to minimise TTL coupling. We show that both imaging systems meet the LISA requirement of  ±25 μm rad‑1 for interfering beams with relative angles of up to  ±300 μrad. Furthermore, we found a dependency of the TTL coupling on beam properties such as the waist size and location, which we characterised both theoretically and experimentally.

  2. In-flight thermal experiments for LISA Pathfinder: Simulating temperature noise at the Inertial Sensors

    International Nuclear Information System (INIS)

    Armano, M; Audley, H; Born, M; Danzmann, K; Diepholz, I; Auger, G; Binetruy, P; Baird, J; Bortoluzzi, D; Brandt, N; Fitzsimons, E; Bursi, A; Caleno, M; Cavalleri, A; Cesarini, A; Dolesi, R; Ferroni, V; Cruise, M; Dunbar, N; Ferraioli, L

    2015-01-01

    Thermal Diagnostics experiments to be carried out on board LISA Pathfinder (LPF) will yield a detailed characterisation of how temperature fluctuations affect the LTP (LISA Technology Package) instrument performance, a crucial information for future space based gravitational wave detectors as the proposed eLISA. Amongst them, the study of temperature gradient fluctuations around the test masses of the Inertial Sensors will provide as well information regarding the contribution of the Brownian noise, which is expected to limit the LTP sensitivity at frequencies close to 1 mHz during some LTP experiments. In this paper we report on how these kind of Thermal Diagnostics experiments were simulated in the last LPF Simulation Campaign (November, 2013) involving all the LPF Data Analysis team and using an end-to-end simulator of the whole spacecraft. Such simulation campaign was conducted under the framework of the preparation for LPF operations. (paper)

  3. Advancements of the Lightweight Integrated Solar Array and Transceiver (LISA-T) Small Spacecraft System

    Science.gov (United States)

    Lockett, Tiffany Russell; Martinez, Armando; Boyd, Darren; SanSouice, Michael; Farmer, Brandon; Schneider, Todd; Laue, Greg; Fabisinski, Leo; Johnson, Les; Carr, John A.

    2015-01-01

    This paper describes recent advancements of the Lightweight Integrated Solar Array and Transceiver (LISA-T) currently being developed at NASA's Marshall Space Flight Center. The LISA-T array comprises a launch stowed, orbit deployed structure on which thin-film photovoltaic (PV) and antenna devices are embedded. The system provides significant electrical power generation at low weights, high stowage efficiency, and without the need for solar tracking. Leveraging high-volume terrestrial-market PVs also gives the potential for lower array costs. LISA-T is addressing the power starvation epidemic currently seen by many small-scale satellites while also enabling the application of deployable antenna arrays. Herein, an overview of the system and its applications are presented alongside sub-system development progress and environmental testing plans.

  4. The Mock LISA Data Challenges: from challenge 3 to challenge 4

    International Nuclear Information System (INIS)

    Babak, Stanislav; Petiteau, Antoine; Robinson, Emma L; Baker, John G; McWilliams, Sean T; Arnaud, Keith A; Benacquista, Matthew J; Cornish, Neil J; Adams, Matt; Larson, Shane L; Mandel, Ilya; Porter, Edward K; Vallisneri, Michele; Cutler, Curt; Vecchio, Alberto; Blaut, Arkadiusz; Bridges, Michael; Feroz, Farhan; Cohen, Michael; Gair, Jonathan R.

    2010-01-01

    The Mock LISA Data Challenges are a program to demonstrate LISA data-analysis capabilities and to encourage their development. Each round of challenges consists of one or more datasets containing simulated instrument noise and gravitational waves from sources of undisclosed parameters. Participants analyze the datasets and report best-fit solutions for the source parameters. Here we present the results of the third challenge, issued in April 2008, which demonstrated the positive recovery of signals from chirping galactic binaries, from spinning supermassive-black-hole binaries (with optimal SNRs between ∼10 and 2000), from simultaneous extreme-mass-ratio inspirals (SNRs of 10-50), from cosmic-string-cusp bursts (SNRs of 10-100), and from a relatively loud isotropic background with Ω gw (f) ∼ 10 -11 , slightly below the LISA instrument noise.

  5. The Mock LISA Data Challenges: from challenge 3 to challenge 4

    Energy Technology Data Exchange (ETDEWEB)

    Babak, Stanislav; Petiteau, Antoine; Robinson, Emma L [Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut), Am Muehlenberg 1, D-14476 Golm bei Potsdam (Germany); Baker, John G; McWilliams, Sean T; Arnaud, Keith A [Gravitational Astrophysics Laboratory, NASA Goddard Space Flight Center, 8800 Greenbelt Rd, Greenbelt, MD 20771 (United States); Benacquista, Matthew J [Center for Gravitational Wave Astronomy, University of Texas at Brownsville, Brownsville, TX 78520 (United States); Cornish, Neil J; Adams, Matt [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Larson, Shane L [Department of Physics, Utah State University, Logan, UT 84322 (United States); Mandel, Ilya [Department of Physics and Astronomy, Northwestern University, Evanston, IL (United States); Porter, Edward K [APC, UMR 7164, University Paris 7 Denis Diderot, 10, rue Alice Domon et Leonie Duquet, 75025 Paris Cedex 13 (France); Vallisneri, Michele; Cutler, Curt [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Vecchio, Alberto [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B152TT (United Kingdom); Blaut, Arkadiusz [Institute of Theoretical Physics, University of Wroclaw, Wroclaw (Poland); Bridges, Michael; Feroz, Farhan [Astrophysics Group, Cavendish Laboratory, University of Cambridge, Cambridge CB30HE (United Kingdom); Cohen, Michael [Theoretical Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Gair, Jonathan R., E-mail: Michele.Vallisneri@jpl.nasa.go [Institute of Astronomy, University of Cambridge, Cambridge CB30HA (United Kingdom)

    2010-04-21

    The Mock LISA Data Challenges are a program to demonstrate LISA data-analysis capabilities and to encourage their development. Each round of challenges consists of one or more datasets containing simulated instrument noise and gravitational waves from sources of undisclosed parameters. Participants analyze the datasets and report best-fit solutions for the source parameters. Here we present the results of the third challenge, issued in April 2008, which demonstrated the positive recovery of signals from chirping galactic binaries, from spinning supermassive-black-hole binaries (with optimal SNRs between approx10 and 2000), from simultaneous extreme-mass-ratio inspirals (SNRs of 10-50), from cosmic-string-cusp bursts (SNRs of 10-100), and from a relatively loud isotropic background with OMEGA{sub gw}(f) approx 10{sup -11}, slightly below the LISA instrument noise.

  6. LISA technologies in new light: exploring alternatives for charge management and optical bench construction

    Science.gov (United States)

    Ciani, Giacomo; Chilton, Andrew; Olatunde, Taiwo; Apple, Stephen; Conklin, John W.; Mueller, Guido

    2015-08-01

    A LISA-like gravitational wave observatory is the choice candidate for ESA's L3 large mission scheduled to launch in 2034. The LISA Test Package (LTP) mission will launch later this year and test many critical technologies needed for such an observatory, among which are picometer interferometry in space and UV charge management of the Test Mass (TM). The design of these subsystems has been frozen many years ago during the final formulation of the LTP mission; since then, the LISA mission concept has evolved and new technologies have become available, making it possible to re-think the way these subsystem are implemented. With the final formulation of the L3 mission still years in the future and the LTP results expected in about one year, now is an ideal time look for areas of possible improvement and explore alternative implementations that can enhance performance, reduce costs or mitigate risks.Recently developed UV LED are lighter, cheaper and more powerful than traditional mercury lamps; in addition, their fast response time can be used to implement AC discharge techniques that can save even more space and power, and provide a more precise control of the charge.The most recent iteration of the mission baseline design allows for eliminating some of the optical components initially deemed essential; paired with the use of polarization multiplexing, this permits a redesign of the optical bench that simplifies the layout and enables a modular approach to machining and assembly, thus reducing the risks and costs associated with the current monolithic design without compromising the picometer stability of the optical path.Leveraging on extensive previous experience with LISA interferometry and the availability of a torsion pendulum-based LISA test-bed, the University of Florida LISA group is working at developing, demonstrating and optimizing both these technologies. I will describe the most recent advancements and results.

  7. MONA, LISA and VINCI Soon Ready to Travel to Paranal

    Science.gov (United States)

    2000-11-01

    First Instruments for the VLT Interferometer Summary A few months from now, light from celestial objects will be directed for the first time towards ESO's Very Large Telescope Interferometer (VLTI) at the Paranal Observatory (Chile). During this "First Light" event and the subsequent test phase, the light will be recorded with a special test instrument, VINCI (VLT INterferometer Commissioning Instrument). The main components of this high-tech instrument are aptly named MONA (a system that combines the light beams from several telescopes by means of optical fibers) and LISA (the infrared camera). VINCI was designed and constructed within a fruitful collaboration between ESO and several research institutes and industrial companies in France and Germany . It is now being assembled at the ESO Headquarters in Garching (Germany) and will soon be ready for installation at the telescope on Paranal. With the VLTI and VINCI, Europe's astronomers are now entering the first, crucial phase of an exciting scientific and technology venture that will ultimately put the world's most powerful optical/IR interferometric facility in their hands . PR Photo 31/00 : VINCI during tests at the ESO Headquarters in Garching. The VLT Interferometer (VLTI) ESO Press Photo 31/00 ESO Press Photo 31/00 [Preview; JPEG: 400 x 301; 43k] [Normal; JPEG: 800 x 602;208xk] [Full-Res; JPEG: 1923 x 1448; 2.2Mb] PR Photo 31/00 shows the various components of the complex VINCI instrument for the VLT Interferometer , during the current tests at the Optical Laboratory at the ESO Headquarters in Garching (Germany). It will later be installed in "clean-room" conditions within the Interferometric Laboratory at the Paranal Observatory. This electronic photo was obtained for documentary purposes. VINCI (VLT INterferometer Commissioning Instrument) is the "First Light" instrument for the Very Large Telescope Interferometer (VLTI) at the Paranal Observatory (Chile). Early in 2001, it will be used for the first tests

  8. LTP - LISA technology package: Development challenges of a spaceborne fundamental physics experiment

    International Nuclear Information System (INIS)

    Gerndt, R

    2009-01-01

    The LISA Technology Package (LTP) is the main payload onboard the LISA Pathfinder Spacecraft. The LTP Instrument together with the Drag-Free Attitude Control System (DFACS) and the respective LTP and DFACS operational software forms the LTP Experiment. It is completed by the FEEPs of the LPF spacecraft that are controlled by DFACS in order to control the spacecraft's attitude along with the experiment's needs. This article concentrates on aspects of the Industrial development of the LTP Instrument items and on essential performance issues of LTP. Examples of investigations on specific issue will highlight the kind of special problems to be solved for LTP in close cooperation with the Scientific Community.

  9. Acoustic waves and the detectability of first-order phase transitions by eLISA

    Science.gov (United States)

    Weir, David J.

    2017-05-01

    In various extensions of the Standard Model it is possible that the electroweak phase transition was first order. This would have been a violent process, involving the formation of bubbles and associated shock waves. Not only would the collision of these bubbles and shock waves be a detectable source of gravitational waves, but persistent acoustic waves could enhance the signal and improve prospects of detection by eLISA. I summarise the results of a recent campaign to model such a phase transition based on large-scale hydrodynamical simulations, and its implications for the eLISA mission.

  10. From LPF to eLISA: new approach in payload software

    Science.gov (United States)

    Gesa, Ll.; Martin, V.; Conchillo, A.; Ortega, J. A.; Mateos, I.; Torrents, A.; Lopez-Zaragoza, J. P.; Rivas, F.; Lloro, I.; Nofrarias, M.; Sopuerta, CF.

    2017-05-01

    eLISA will be the first observatory in space to explore the Gravitational Universe. It will gather revolutionary information about the dark universe. This implies a robust and reliable embedded control software and hardware working together. With the lessons learnt with the LISA Pathfinder payload software as baseline, we will introduce in this short article the key concepts and new approaches that our group is working on in terms of software: multiprocessor, self-modifying-code strategies, 100% hardware and software monitoring, embedded scripting, Time and Space Partition among others.

  11. Doing Science with eLISA: Astrophysics and Cosmology in the Millihertz Regime

    Science.gov (United States)

    Amaro, Seoane, Pau; Aoudia, Sofiane; Babak, Stanislav; Binetruy, Pierre; Berti, Amanuele; Bohe, Alejandro; Caprini, Chiara; Colpi, Monica; Cornish, Neil J.; Danzmann, Karsten; hide

    2012-01-01

    This document introduces the exciting and fundamentally new science and astronomy that the European New Gravitational Wave Observatory (NGO) mission (derived from the previous LISA proposal) will deliver. The mission (which we will refer to by its informal name eLISA ) will survey for the first time the low-frequency gravitational wave band (about 0.1 mHz to 1 Hz), with sufficient sensitivity to detect interesting individual astrophysical sources out to z = 15. The measurements described here will address the basic scientific goals that have been captured in ESA s New Gravitational Wave Observatory Science Requirements Document ; they are presented here so that the wider scientific community can have access to them. The eLISA mission will discover and study a variety of cosmic events and systems with high sensitivity: coalescences of massive black holes binaries, brought together by galaxy mergers; mergers of earlier, less-massive black holes during the epoch of hierarchical galaxy and black-hole growth; stellar-mass black holes and compact stars in orbits just skimming the horizons of massive black holes in galactic nuclei of the present era; extremely compact white dwarf binaries in our Galaxy, a rich source of information about binary evolution and about future Type Ia supernovae; and possibly most interesting of all, the uncertain and unpredicted sources, for example relics of inflation and of the symmetry-breaking epoch directly after the Big Bang. eLISA s measurements will allow detailed studies of these signals with high signal-to-noise ratio, addressing most of the key scientific questions raised by ESA s Cosmic Vision programme in the areas of astrophysics and cosmology. They will also provide stringent tests of general relativity in the strong-field dynamical regime, which cannot be probed in any other way. This document not only describes the science but also gives an overview on the mission design and orbits. LISA s heritage in the eLISA design will be

  12. eLISA eccentricity measurements as tracers of binary black hole formation

    OpenAIRE

    Nishizawa, Atsushi; Berti, Emanuele; Klein, Antoine; Sesana, Alberto

    2016-01-01

    Up to hundreds of black hole binaries individually resolvable by eLISA will coalesce in the Advanced LIGO/Virgo band within ten years, allowing for multi-band gravitational wave observations. Binaries formed via dynamical interactions in dense star clusters are expected to have eccentricities $e_0\\sim 10^{-3}$-$10^{-1}$ at the frequencies $f_0=10^{-2}$ Hz where eLISA is most sensitive, while binaries formed in the field should have negligible eccentricity in both frequency bands. We estimate ...

  13. Sky Localization of Complete Inspiral-Merger-Ringdown Signals for Nonspinning Black Hole Binaries with LISA

    Science.gov (United States)

    McWilliams, Sean T.; Lang, Ryan N.; Baker, John G.; Thorpe, James Ira

    2011-01-01

    We investigate the capability of LISA to measure the sky position of equal-mass, nonspinning black hole binaries, including for the first time the entire inspiral-merger-ringdown signal, the effect of the LISA orbits, and the complete three-channel LISA response. For an ensemble of systems near the peak of LISA's sensitivity band, with total rest mass of 2 x l0(exp 6) Stellar Mass at a redshift of z = 1 with random orientations and sky positions, we find median sky localization errors of approximately approx. 3 arcminutes. This is comparable to the field of view of powerful electromagnetic telescopes, such as the James Webb Space Telescope, that could be used to search for electromagnetic signals associated with merging black holes. We investigate the way in which parameter errors decrease with measurement time, focusing specifically on the additional information provided during the merger-ringdown segment of the signal. We find that this information improves all parameter estimates directly, rather than through diminishing correlations with any subset of well-determined parameters.

  14. Estudo bibliométrico do descritor “Ergonomia” na base LISA

    Directory of Open Access Journals (Sweden)

    Eliana Maria dos Santos Bahia

    2011-03-01

    Full Text Available Objetivo: O estudo analisa a produção científica sobre ergonomia utilizando a base de dados Library and Information Science Abstracts (LISA. A base de dados LISA, iniciada em 1969, mantém sua cobertura temática na área de Biblioteconomia e Ciência da Informação.Método: No estudo utilizou-se o método da bibliometria aplicada para verificar a produção científica indexada.Resultados: Entre os resultados da busca de termos indexados na base de dados LISA, encontraram-se 503 artigos com o termo “Ergonomic”; 352 artigos, com a expressão “Design”; 111 artigos com o descritor “Systems”; 110 artigos com o termo “Work”; e , 98 artigos com o termo “Evaluation”. Dentre os 34 títulos de periódicos, 4 títulos cobrem 79% dos artigos que tratam sobre Ergonomia na base LISA. Os demais 30 títulos de periódicos cobrem 21% dos artigos indexados sob essa temática.Conclusões: O presente estudo bibliométrico oferece possibilita um panorama de como a ergonomia é percebida na área da Biblioteconomia e Ciência da Informação.

  15. LISA detection of massive black hole binaries: imprint of seed populations and extreme recoils

    International Nuclear Information System (INIS)

    Sesana, A; Volonteri, M; Haardt, F

    2009-01-01

    All the physical processes involved in the formation, merging and accretion history of massive black holes along the hierarchical build-up of cosmic structures are likely to leave an imprint on the gravitational waves detectable by future space-borne missions, such as LISA. We report here the results of recent studies, carried out by means of dedicated simulations of black hole build-up, aiming at understanding the impact on LISA observations of two ingredients that are crucial in every massive black hole formation scenario, namely: (i) the nature and abundance of the first black hole seeds and (ii) the large gravitational recoils following the merger of highly spinning black holes. We predict LISA detection rates spanning two orders of magnitude, in the range 3-300 events per year, depending on the detail of the assumed massive black hole seed model. On the other hand, large recoil velocities do not dramatically compromise the efficiency of LISA observations. The number of detections may drop substantially (by ∼60%), in scenarios characterized by abundant light seeds, but if seeds are already massive and/or relatively rare, the detection rate is basically unaffected.

  16. Numerical code to determine the particle trapping region in the LISA machine

    International Nuclear Information System (INIS)

    Azevedo, M.T. de; Raposo, C.C. de; Tomimura, A.

    1984-01-01

    A numerical code is constructed to determine the trapping region in machine like LISA. The variable magnetic field is two deimensional and is coupled to the Runge-Kutta through the Tchebichev polynomial. Various particle orbits including particle interactions were analysed. Beside this, a strong electric field is introduced to see the possible effects happening inside the plasma. (Author) [pt

  17. Interpolation of the magnetic field at the test masses in eLISA

    International Nuclear Information System (INIS)

    Mateos, I; Díaz-Aguiló, M; Ramos-Castro, J; García-Berro, E; Lobo, A

    2015-01-01

    A feasible design for a magnetic diagnostics subsystem for eLISA will be based on that of its precursor mission, LISA Pathfinder. Previous experience indicates that magnetic field estimation at the positions of the test masses has certain complications. This is due to two reasons. The first is that magnetometers usually back-act due to their measurement principles (i.e., they also create their own magnetic fields), while the second is that the sensors selected for LISA Pathfinder have a large size, which conflicts with space resolution and with the possibility of having a sufficient number of them to properly map the magnetic field around the test masses. However, high-sensitivity and small-sized sensors that significantly mitigate the two aforementioned limitations exist, and have been proposed to overcome these problems. Thus, these sensors will be likely selected for the magnetic diagnostics subsystem of eLISA. Here we perform a quantitative analysis of the new magnetic subsystem, as it is currently conceived, and assess the feasibility of selecting these sensors in the final configuration of the magnetic diagnostic subsystem. (paper)

  18. Modulation of LISA free-fall orbits due to the Earth-Moon system

    Energy Technology Data Exchange (ETDEWEB)

    Cerdonio, Massimo; Marzari, Francesco [Department of Physics, University of Padova and INFN Padova, via Marzolo 8, I-35131 Padova (Italy); De Marchi, Fabrizio [Department of Physics, University of Trento and INFN Trento, I-38100 Povo (Trento) (Italy); De Pietri, Roberto [Department of Physics, University of Parma and INFN Parma I-43100 Parma (Italy); Jetzer, Philippe [Institute of Theoretical Physics, University of Zuerich, Winterhurerstrasse 190, 8057 Zuerich (Switzerland); Mazzolo, Giulio [Max Planck Institut fuer Gravitationsphysik, Callinstrasse 38, 30167 Hannover (Germany); Ortolan, Antonello [INFN Laboratori Nazionali di Legnaro, Viale dell' Universita 35020 Legnaro (Padova) (Italy); Sereno, Mauro, E-mail: fdemarchi@science.unitn.i [Dipartimento di Fisica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)

    2010-08-21

    We calculate the effect of the Earth-Moon (EM) system on the free-fall motion of LISA test masses. We show that the periodic gravitational pulling of the EM system induces a resonance with fundamental frequency 1 yr{sup -1} and a series of periodic perturbations with frequencies equal to integer harmonics of the synodic month ({approx_equal} 3.92 x 10{sup -7} Hz). We then evaluate the effects of these perturbations (up to the 6th harmonics) on the relative motions between each test mass couple, finding that they range between 3 mm and 10 pm for the 2nd and 6th harmonic, respectively. If we take the LISA sensitivity curve, as extrapolated down to 10{sup -6} Hz in Bender (2003 Class. Quantum Grav. 20 301-10), we obtain that a few harmonics of the EM system can be detected in the Doppler data collected by the LISA space mission. This suggests that the EM system gravitational near field could provide an additional crosscheck to the calibration of LISA, as extended to such low frequencies.

  19. Modulation of LISA free-fall orbits due to the Earth-Moon system

    International Nuclear Information System (INIS)

    Cerdonio, Massimo; Marzari, Francesco; De Marchi, Fabrizio; De Pietri, Roberto; Jetzer, Philippe; Mazzolo, Giulio; Ortolan, Antonello; Sereno, Mauro

    2010-01-01

    We calculate the effect of the Earth-Moon (EM) system on the free-fall motion of LISA test masses. We show that the periodic gravitational pulling of the EM system induces a resonance with fundamental frequency 1 yr -1 and a series of periodic perturbations with frequencies equal to integer harmonics of the synodic month (≅ 3.92 x 10 -7 Hz). We then evaluate the effects of these perturbations (up to the 6th harmonics) on the relative motions between each test mass couple, finding that they range between 3 mm and 10 pm for the 2nd and 6th harmonic, respectively. If we take the LISA sensitivity curve, as extrapolated down to 10 -6 Hz in Bender (2003 Class. Quantum Grav. 20 301-10), we obtain that a few harmonics of the EM system can be detected in the Doppler data collected by the LISA space mission. This suggests that the EM system gravitational near field could provide an additional crosscheck to the calibration of LISA, as extended to such low frequencies.

  20. Playing Harry Potter: Essays and interviews on fandom and performance, edited by Lisa S. Brenner

    Directory of Open Access Journals (Sweden)

    Abigail De Kosnik

    2016-09-01

    Full Text Available Lisa S. Brenner, editor. Playing Harry Potter: Essays and interviews on fandom and performance. Jefferson, NC: McFarland, 2015, paperback, $29.95 (238p ISBN 978-0-7864-9657-0; e-book $14.43 (5374 KB ISBN 978-1-4766-2136-4, ASIN B012E9G0R6.

  1. PREFACE: Proceedings of the 7th International LISA Symposium, Barcelona, Spain, 16-20 June 2008

    Science.gov (United States)

    Lobo, Alberto; Sopuerta, Carlos F.

    2009-07-01

    In June 2006 the LISA International Science Team (LIST) accepted the bid presented by the Institut d'Estudis Espacials de Catalunya (IEEC) to host the 7th International LISA Symposium. This was during its 11th meeting at the University of Maryland, just before the 6th edition of the Symposium started in NASA's Goddard Space Flight Center. The 7th International LISA Symposium took place at the city of Barcelona, Spain, from 16-20 June 2008, in the premises of CosmoCaixa, a modern Science Museum located in the hills near Tibidabo. Almost 240 delegates registered for the event, a record breaking figure compared to previous editions of the Symposium. Many of the most renowned world experts in LISA, Gravitational Wave Science, and Astronomy, as well as Engineers, attended LISA 7 and produced state-of-the-art presentations, while everybody benefited from the opportunity to have live discussions during the week in a friendly environment. The programme included 31 invited plenary lectures in the mornings, and 8 parallel sessions in the afternoons. These were classified into 7 major areas of research: LISA Technology, LISA PathFinder, LISA PathFinder Data Analysis, LISA Data Analysis, Gravitational Wave sources, Cosmology and Fundamental Physics with LISA and Other Gravitational Wave Detectors. 138 abstracts for communications were received, of which a selection was made by the session convenors which would fit time constraints. Up to 63 posters completed the scientific programme. More details on the programme, including some of the talks, can be found at the Symposium website: http://www.ice.cat/research/LISA_Symposium. There was however a remarkable add-on: Professor Clifford Will delivered a startling presentation to the general public, who completely filled the Auditori—the main Conference Room, 320 seats—and were invited to ask questions to the speaker who had boldly guided them through the daunting world of Black Holes, Waves of Gravity, and other Warped Ideas of

  2. Massive black-hole binary inspirals: results from the LISA parameter estimation taskforce

    International Nuclear Information System (INIS)

    Arun, K G; Babak, Stas; Porter, Edward K; Sintes, Alicia M; Berti, Emanuele; Cutler, Curt; Cornish, Neil; Gair, Jonathan; Hughes, Scott A; Lang, Ryan N; Iyer, Bala R; Sinha, Siddhartha; Mandel, Ilya; Sathyaprakash, Bangalore S; Van Den Broeck, Chris; Trias, Miquel; Volonteri, Marta

    2009-01-01

    The LISA Parameter Estimation Taskforce was formed in September 2007 to provide the LISA Project with vetted codes, source distribution models and results related to parameter estimation. The Taskforce's goal is to be able to quickly calculate the impact of any mission design changes on LISA's science capabilities, based on reasonable estimates of the distribution of astrophysical sources in the universe. This paper describes our Taskforce's work on massive black-hole binaries (MBHBs). Given present uncertainties in the formation history of MBHBs, we adopt four different population models, based on (i) whether the initial black-hole seeds are small or large and (ii) whether accretion is efficient or inefficient at spinning up the holes. We compare four largely independent codes for calculating LISA's parameter-estimation capabilities. All codes are based on the Fisher-matrix approximation, but in the past they used somewhat different signal models, source parametrizations and noise curves. We show that once these differences are removed, the four codes give results in extremely close agreement with each other. Using a code that includes both spin precession and higher harmonics in the gravitational-wave signal, we carry out Monte Carlo simulations and determine the number of events that can be detected and accurately localized in our four population models.

  3. The end-to-end testbed of the optical metrology system on-board LISA Pathfinder

    Energy Technology Data Exchange (ETDEWEB)

    Steier, F; Cervantes, F Guzman; Marin, A F GarcIa; Heinzel, G; Danzmann, K [Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut) and Universitaet Hannover (Germany); Gerardi, D, E-mail: frank.steier@aei.mpg.d [EADS Astrium Satellites GmbH, Friedrichshafen (Germany)

    2009-05-07

    LISA Pathfinder is a technology demonstration mission for the Laser Interferometer Space Antenna (LISA). The main experiment on-board LISA Pathfinder is the so-called LISA Technology Package (LTP) which has the aim to measure the differential acceleration between two free-falling test masses with an accuracy of 3 x 10{sup -14} ms{sup -2} Hz{sup -1/2} between 1 mHz and 30 mHz. This measurement is performed interferometrically by the optical metrology system (OMS) on-board LISA Pathfinder. In this paper, we present the development of an experimental end-to-end testbed of the entire OMS. It includes the interferometer and its sub-units, the interferometer backend which is a phasemeter and the processing of the phasemeter output data. Furthermore, three-axes piezo-actuated mirrors are used instead of the free-falling test masses for the characterization of the dynamic behaviour of the system and some parts of the drag-free and attitude control system (DFACS) which controls the test masses and the satellite. The end-to-end testbed includes all parts of the LTP that can reasonably be tested on earth without free-falling test masses. At its present status it consists mainly of breadboard components. Some of those have already been replaced by engineering models of the LTP experiment. In the next steps, further engineering and flight models will also be inserted in this testbed and tested against well-characterized breadboard components. The presented testbed is an important reference for the unit tests and can also be used for validation of the on-board experiment during the mission.

  4. Study of test-mass charging process in the LISA missions due to diffuse γ-rays

    International Nuclear Information System (INIS)

    Finetti, N; Scrimaglio, R; Grimani, C; Fabi, M

    2009-01-01

    Gravitational inertial sensors will be placed on board the Laser Interferometer Space Antenna (LISA) and aboard its precursor mission LISA Pathfinder (LISA-PF) in order to detect low frequency gravitational waves in space. Free-floating test-masses (Au 7 Pt 3 cubes) will be housed in inertial sensors for detecting possible laser signal variations induced by gravitational waves. Charging of the LISA test-masses due to exposure of the spacecraft to cosmic radiation and energetic solar particles will affect operation of gravitational inertial sensors. In this paper we report on the role of diffuse γ-rays in charging the LISA and LISA-PF test-masses with respect to protons and helium nuclei. The diffuse γ-ray flux in the Galaxy has been interpolated taking into account the outcomes of recent calculations. A comparison with γ-ray observations gathered by different experiments (COMPTEL and EGRET, Milagro, Whipple, HEGRA, TIBET) has been carried out. Simulations of the test-mass charging process have been performed by means of the FLUKA2006.3b package. Monte Carlo simulations of the interaction of cosmic particles with the LISA spacecraft indicate that the diffuse γ-ray contribution to the average steady-state test-mass charging rate and to the single-sided power spectrum of the charge rate noise is marginal with respect to that due to galactic cosmic-rays.

  5. In-orbit performance of the LISA Pathfinder drag-free and attitude control system

    Science.gov (United States)

    Schleicher, A.; Ziegler, T.; Schubert, R.; Brandt, N.; Bergner, P.; Johann, U.; Fichter, W.; Grzymisch, J.

    2018-04-01

    LISA Pathfinder is a technology demonstrator mission that was funded by the European Space Agency and that was launched on December 3, 2015. LISA Pathfinder has been conducting experiments to demonstrate key technologies for the gravitational wave observatory LISA in its operational orbit at the L1 Lagrange point of the Earth-Sun system until final switch off on July 18, 2017. These key technologies include the inertial sensors, the optical metrology system, a set of µ-propulsion cold gas thrusters and in particular the high performance drag-free and attitude control system (DFACS) that controls the spacecraft in 15 degrees of freedom during its science phase. The main goal of the DFACS is to shield the two test masses inside the inertial sensors from all external disturbances to achieve a residual differential acceleration between the two test masses of less than 3 × 10-14 m/s2/√Hz over the frequency bandwidth of 1-30 mHz. This paper focuses on two important aspects of the DFACS that has been in use on LISA Pathfinder: the DFACS Accelerometer mode and the main DFACS Science mode. The Accelerometer mode is used to capture the test masses after release into free flight from the mechanical grabbing mechanism. The main DFACS Science Mode is used for the actual drag-free science operation. The DFACS control system has very strong interfaces with the LISA Technology Package payload which is a key aspect to master the design, development, and analysis of the DFACS. Linear as well as non-linear control methods are applied. The paper provides pre-flight predictions for the performance of both control modes and compares these predictions to the performance that is currently achieved in-orbit. Some results are also discussed for the mode transitions up to science mode, but the focus of the paper is on the Accelerometer mode performance and on the performance of the Science mode in steady state. Based on the achieved results, some lessons learnt are formulated to extend

  6. Review: Lisa Mackenrodt, Swahili Spirit Possession and Islamic Healing in Contemporary Tanzania: The Jinn Fly on Friday (2011 Buchbesprechung: Lisa Mackenrodt, Swahili Spirit Possession and Islamic Healing in Contemporary Tanzania: The Jinn Fly on Friday (2011

    Directory of Open Access Journals (Sweden)

    Jigal Beez

    2013-01-01

    Full Text Available Review of the monograph:Lisa Mackenrodt, Swahili Spirit Possession and Islamic Healing in Contemporary Tanzania: The Jinn Fly on Friday, Hamburg: Verlag Dr. Kovač, 2011, ISBN 978-3-8300-5806-9, 216 pagesBesprechung der Monographie:Lisa Mackenrodt, Swahili Spirit Possession and Islamic Healing in Contemporary Tanzania: The Jinn Fly on Friday, Hamburg: Verlag Dr. Kovač, 2011, ISBN 978-3-8300-5806-9, 216 Seiten

  7. LISA Pathfinder E2E performance simulation: optical and self-gravity stability analysis

    Science.gov (United States)

    Brandt, N.; Fichter, W.; Kersten, M.; Lucarelli, S.; Montemurro, F.

    2005-05-01

    End-to-end (E2E) modelling and simulation, i.e. verifying the science performance of LISA Pathfinder (spacecraft and payload), is mandatory in order to minimize mission risks. In this paper, focus is on two particular applications of the E2E performance simulator currently being developed at EADS Astrium GmbH: the opto-dynamical stability and the self-gravity disturbance stability analysis. The E2E models applied here comprise the opto-dynamical modelling of the optical metrology systems (OMS) laser interferometry, the thermo-elastic distortion modelling of the OMS optical elements and the self-gravity disturbance model accounting for structural distortions. Preliminary analysis results are presented in detail, identifying shortcomings of the current LISA technology package (LTP) mounting baseline. As a consequence, the design is now being revised.

  8. LISA Pathfinder E2E performance simulation: optical and self-gravity stability analysis

    International Nuclear Information System (INIS)

    Brandt, N; Fichter, W; Kersten, M; Lucarelli, S; Montemurro, F

    2005-01-01

    End-to-end (E2E) modelling and simulation, i.e. verifying the science performance of LISA Pathfinder (spacecraft and payload), is mandatory in order to minimize mission risks. In this paper, focus is on two particular applications of the E2E performance simulator currently being developed at EADS Astrium GmbH: the opto-dynamical stability and the self-gravity disturbance stability analysis. The E2E models applied here comprise the opto-dynamical modelling of the optical metrology systems (OMS) laser interferometry, the thermo-elastic distortion modelling of the OMS optical elements and the self-gravity disturbance model accounting for structural distortions. Preliminary analysis results are presented in detail, identifying shortcomings of the current LISA technology package (LTP) mounting baseline. As a consequence, the design is now being revised

  9. Lifetime testing UV LEDs for use in the LISA charge management system

    Science.gov (United States)

    Hollington, D.; Baird, J. T.; Sumner, T. J.; Wass, P. J.

    2017-10-01

    As a future charge management light source, UV light-emitting diodes (UV LEDs) offer far superior performance in a range of metrics compared to the mercury lamps used in the past. As part of a qualification program a number of short wavelength UV LEDs have been subjected to a series of lifetime tests for potential use on the laser interferometer space antenna (LISA) mission. These tests were performed at realistic output levels for both fast and continuous discharging in either a DC or pulsed mode of operation and included a DC fast discharge test spanning 50 days, a temperature dependent pulsed fast discharge test spanning 21 days and a pulsed continuous discharge test spanning 507 days. Two types of UV LED have demonstrated lifetimes equivalent to over 25 years of realistic mission usage with one type providing a baseline for LISA and the other offering a backup solution.

  10. Lifetime testing UV LEDs for use in the LISA charge management system

    International Nuclear Information System (INIS)

    Hollington, D; Baird, J T; Sumner, T J; Wass, P J

    2017-01-01

    As a future charge management light source, UV light-emitting diodes (UV LEDs) offer far superior performance in a range of metrics compared to the mercury lamps used in the past. As part of a qualification program a number of short wavelength UV LEDs have been subjected to a series of lifetime tests for potential use on the laser interferometer space antenna (LISA) mission. These tests were performed at realistic output levels for both fast and continuous discharging in either a DC or pulsed mode of operation and included a DC fast discharge test spanning 50 days, a temperature dependent pulsed fast discharge test spanning 21 days and a pulsed continuous discharge test spanning 507 days. Two types of UV LED have demonstrated lifetimes equivalent to over 25 years of realistic mission usage with one type providing a baseline for LISA and the other offering a backup solution. (paper)

  11. LISA: A performance assessment code for geological repositories of radioactive waste

    International Nuclear Information System (INIS)

    Bertozzi, G.; Saltelli, A.

    1985-01-01

    LISA, developed at JRC-Ispra, is a statistical code, which calculates the radiation exposures and risks associated with radionuclide releases from geological repositories of nuclear waste. The assessment methodology is described briefly. It requires that a number of probabilistic components be quantified and introduced in the analysis; the results are thus expressed in terms of risk. The subjective judgment of experts may be necessary to quantify the probabilities of occurrence of rare geological events. Because of large uncertainties in input data, statistical treatment of the Monte Carlo type is utilized for the analysis; thus, the output from LISA is obtained in the form of distributions. A few results of an application to a probabilistic scenario for a repository mined in a clay bed are illustrated

  12. Construction of an optical test-bed for eLISA

    International Nuclear Information System (INIS)

    Lieser, Maike; Isleif, K-S; Schuster, S; Tröbs, M; Veith, S; Heinzel, G; Danzmann, K; Fitzsimons, E; Killow, C; Perreur-Lloyd, M; Robertson, D; Ward, H

    2016-01-01

    In the planned eLISA mission a key part of the system is the optical bench that holds the interferometers for reading out the inter-spacecraft distance and the test mass position. We report on ongoing technology development for the eLISA optical system like the back-link between the optical benches and the science interferometer where the local beam is interfered with the received beam from the distant spacecraft. The focus will be on a setup to investigate the tilt-to-pathlength coupling in the science interferometer. To test the science interferometer in the lab a second bench providing a laser beam and a reference interferometer is needed. We present a setup with two ultra-stable low expansion glass benches and bonded optics. To suppress the tilt-to-pathlength coupling to the required level (few μm/rad) imaging optics are placed in front of the interferometer photo diodes. (paper)

  13. The Mock LISA Data Challenges: from Challenge 1B to Challenge 3

    International Nuclear Information System (INIS)

    Babak, Stanislav; Porter, Edward K; Gair, Jonathan; Baker, John G; Arnaud, Keith; Benacquista, Matthew J; Cornish, Neil J; Crowder, Jeff; Vallisneri, Michele; Cutler, Curt; Larson, Shane L; Plagnol, Eric; Vecchio, Alberto; Barack, Leor; Blaut, Arkadiusz; Fairhurst, Stephen; Harry, Ian; Gong Xuefei; Khurana, Deepak; Krolak, Andrzej

    2008-01-01

    The Mock LISA Data Challenges are a programme to demonstrate and encourage the development of LISA data-analysis capabilities, tools and techniques. At the time of this workshop, three rounds of challenges had been completed, and the next was about to start. In this paper we provide a critical analysis of the entries to the latest completed round, Challenge 1B. The entries confirm the consolidation of a range of data-analysis techniques for galactic and massive-black-hole binaries, and they include the first convincing examples of detection and parameter estimation of extreme-mass-ratio inspiral sources. In this paper we also introduce the next round, Challenge 3. Its data sets feature more realistic waveform models (e.g., galactic binaries may now chirp, and massive-black-hole binaries may precess due to spin interactions), as well as new source classes (bursts from cosmic strings, isotropic stochastic backgrounds) and more complicated nonsymmetric instrument noise

  14. arXiv Probing non-Gaussian Stochastic Gravitational Wave Backgrounds with LISA

    CERN Document Server

    Bartolo, Nicola; Figueroa, Daniel G.; Garcia-Bellido, Juan; Peloso, Marco; Pieroni, Mauro; Ricciardone, Angelo; Sakellariadou, Mairi; Sorbo, Lorenzo; Tasinato, Gianmassimo

    The stochastic gravitational wave background (SGWB) contains a wealth of information on astrophysical and cosmological processes. A major challenge of upcoming years will be to extract the information contained in this background and to disentangle the contributions of different sources. In this paper we provide the formalism to extract, from the correlation of three signals in the Laser Interferometer Space Antenna (LISA), information about the tensor three-point function, which characterizes the non-Gaussian properties of the SGWB. Compared to the two-point function, the SGWB three-point function has a richer dependence on the gravitational wave momenta and chiralities, and a larger number of signal channels. It can be used therefore as a powerful discriminator between different models. We provide LISA's response functions to a general SGWB three-point function. As examples, we study in full detail the cases of an equilateral and squeezed SGWB bispectra, and provide the explicit form of the response functio...

  15. LTP - LISA technology package: Development challenges of a spaceborne fundamental physics experiment

    Energy Technology Data Exchange (ETDEWEB)

    Gerndt, R, E-mail: ruediger.gerndt@astrium.eads.ne [Astrium Satellites GmbH, Claude-Dornier-Str., 88090 Immenstaad (Germany)

    2009-03-01

    The LISA Technology Package (LTP) is the main payload onboard the LISA Pathfinder Spacecraft. The LTP Instrument together with the Drag-Free Attitude Control System (DFACS) and the respective LTP and DFACS operational software forms the LTP Experiment. It is completed by the FEEPs of the LPF spacecraft that are controlled by DFACS in order to control the spacecraft's attitude along with the experiment's needs. This article concentrates on aspects of the Industrial development of the LTP Instrument items and on essential performance issues of LTP. Examples of investigations on specific issue will highlight the kind of special problems to be solved for LTP in close cooperation with the Scientific Community.

  16. Detection of Double White Dwarf Binaries with Gaia, LSST and eLISA

    Science.gov (United States)

    Korol, V.; Rossi, E. M.; Groot, P. J.

    2017-03-01

    According to simulations around 108 double degenerate white dwarf binaries are expected to be present in the Milky Way. Due to their intrinsic faintness, the detection of these systems is a challenge, and the total number of detected sources so far amounts only to a few tens. This will change in the next two decades with the advent of Gaia, the LSST and eLISA. We present an estimation of how many compact DWDs with orbital periods less than a few hours we will be able to detect 1) through electromagnetic radiation with Gaia and LSST and 2) through gravitational wave radiation with eLISA. We find that the sample of simultaneous electromagnetic and gravitational waves detections is expected to be substantial, and will provide us a powerful tool for probing the white dwarf astrophysics and the structure of the Milky Way, letting us into the era of multi-messenger astronomy for these sources.

  17. Possible Periodic Orbit Control Maneuvers for an eLISA Mission

    Science.gov (United States)

    Bender, Peter L.; Welter, Gary L.

    2012-01-01

    This paper investigates the possible application of periodic orbit control maneuvers for so-called evolved-LISA (eLISA) missions, i.e., missions for which the constellation arm lengths and mean distance from the Earth are substantially reduced. We find that for missions with arm lengths of 106 km and Earth-trailing distance ranging from approx. 12deg to 20deg over the science lifetime, the occasional use of the spacecraft micro-Newton thrusters for constellation configuration maintenance should be able to essentially eliminate constellation distortion caused by Earth-induced tidal forces at a cost to science time of only a few percent. With interior angle variation kept to approx. +/-0:1deg, the required changes in the angles between the laser beam pointing directions for the two arms from any spacecraft could be kept quite small. This would considerably simplify the apparatus necessary for changing the transmitted beam directions.

  18. Searching for massive black hole binaries in the first Mock LISA Data Challenge

    International Nuclear Information System (INIS)

    Cornish, Neil J; Porter, Edward K

    2007-01-01

    The Mock LISA Data Challenge is a worldwide effort to solve the LISA data analysis problem. We present here our results for the massive black hole binary (BBH) section of round 1. Our results cover challenge 1.2.1, where the coalescence of the binary is seen, and challenge 1.2.2, where the coalescence occurs after the simulated observational period. The data stream is composed of Gaussian instrumental noise plus an unknown BBH waveform. Our search algorithm is based on a variant of the Markov chain Monte Carlo method that uses Metropolis-Hastings sampling and thermostated frequency annealing. We present results from the training data sets where we know the parameter values a priori and the blind data sets where we were informed of the parameter values after the challenge had finished. We demonstrate that our algorithm is able to rapidly locate the sources, accurately recover the source parameters and provide error estimates for the recovered parameters

  19. Supermassive Black Holes as Revealed by LISA: How Gravitational Wave Astronomy Will be a Game Changer

    Science.gov (United States)

    Holley-Bockelmann, Kelly

    2018-04-01

    Astronomers now know that supermassive black holes are in nearly every galaxy.Though these black holes are an observational certainty, nearly every aspect of their evolution -- from their birth, to their fuel source, to their basic dynamics -- is a matter of lively debate. Fortunately, LISA, a space-based gravitational wave observatory set to launch in 2034, will revolutionize this field by providing data that is complementary to electromagnetic observations as well as data in regimes that are electromagnetically dark. This talk will touch on our current understanding of how SMBHs form, evolve, and alter their galaxy host, and will outline the theoretical, computational and observational work needed to make the most of LISA observations.

  20. Lisa B Signorello, ScD, ScM | Division of Cancer Prevention

    Science.gov (United States)

    Lisa Signorello is the Director and Chief of the Cancer Prevention Fellowship Program (CPFP) Branch in the National Cancer Institute's Division of Cancer Prevention. Dr. Signorello served as Deputy Director of the CPFP from August 2014 to November 2017 and came to the NCI after having held academic positions at the Harvard School of Public Health, Harvard Medical School, and Vanderbilt University, as well as having had significant private sector research experience. |

  1. Laser frequency stabilization and stray light issues for LISA and other future multi-spacecraft missions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — "The Laser Interferometer Space Antenna (LISA) is a joint NASA/ESA project which will use laser interferometry between drag-free proof masses to measure...

  2. Demonstration of AC and DC charge control for the LISA test masses

    Science.gov (United States)

    Olatunde, Taiwo Janet

    2018-01-01

    Taiwo Olatunde, Stephen Apple, Andrew Chilton, Samantha Parry, Peter Wass, Guido Mueller, John W. Conklin The residual test mass acceleration in LISA must be below 3 fm/s2/√Hz at all frequencies between 0.1 and 3 mHz. Test mass charge coupled with stray electrical potentials and external electromagnetic fields is a well-known source of acceleration noise. LISA Pathfinder uses Hg lamps emitting mostly around 254 nm to discharge the test masses via photoemission, but a future LISA mission launched around 2030 will likely replace the lamps with newer UV LEDs with lower mass, better power efficiency, smaller size and higher bandwidth. This presentation will discuss charge control demonstrated on the torsion pendulum in AC and DC modes at the University of Florida using latest generation UV LEDs producing light at 240 nm with energy above the work function of pure Au. Initial results of Au quantum efficiency measurements (number of emitted electrons per incident photons) which is critical for bi-polar charge control will also be presented.

  3. Renormalized second post-Newtonian spin contributions to the accumulated orbital phase for LISA sources

    International Nuclear Information System (INIS)

    Gergely, Laszlo Arpad; Mikoczi, Balazs

    2009-01-01

    We give here a new third post-Newtonian (3PN) spin-spin contribution (in the PN parameter ε) to the accumulated orbital phase of a compact binary, arising from the spin-orbit precessional motion of the spins. In the equal mass case, this contribution vanishes, but Laser Interferometer Space Antenna (LISA) sources of merging supermassive binary black holes have typically a mass ratio of 1:10. For such nonequal masses, this 3PN correction is periodic in time, with a period approximately ε -1 times larger than the period of gravitational waves. We derive a renormalized and simpler expression of the spin-spin coefficient at 2PN, as an average over the time scale of this period of the combined 2PN and 3PN contribution. We also find that for LISA sources the quadrupole-monopole contribution to the phase dominates over the spin-spin contribution, while the self-spin contribution is negligible even for the dominant spin. Finally, we define a renormalized total spin coefficient σ to be employed in the search for gravitational waves emitted by LISA sources.

  4. Low-Frequency Gravitational-Wave Science with eLISA/ NGO

    Science.gov (United States)

    Amaro-Seoane, Pau; Aoudia, Sofiane; Babak, Stanislav; Binetruy, Pierre; Berti, Emanuele; Bohe, Alejandro; Caprini, Chiara; Colpi, Monica; Cornish, Neil J.; Danzmann, Karsten; hide

    2011-01-01

    We review the expected science performance of the New Gravitational-Wave Observatory (NGO, a.k.a. eLISA), a mission under study by the European Space Agency for launch in the early 2020s. eLISA will survey the low-frequency gravitational-wave sky (from 0.1 mHz to 1 Hz), detecting and characterizing a broad variety of systems and events throughout the Universe, including the coalescences of massive black holes brought together by galaxy mergers; the inspirals of stellar-mass black holes and compact stars into central galactic black holes; several millions of ultracompact binaries, both detached and mass transferring, in the Galaxy; and possibly unforeseen sources such as the relic gravitational-wave radiation from the early Universe. eLISA's high signal-to-noise measurements will provide new insight into the structure and history of the Universe, and they will test general relativity in its strong-field dynamical regime.

  5. Sub-pm{{\\sqrt{Hz}^{-1}}} non-reciprocal noise in the LISA backlink fiber

    Science.gov (United States)

    Fleddermann, Roland; Diekmann, Christian; Steier, Frank; Tröbs, Michael; Heinzel, Gerhard; Danzmann, Karsten

    2018-04-01

    The future space-based gravitational wave detector laser interferometer space antenna (LISA) requires bidirectional exchange of light between its two optical benches on board of each of its three satellites. The current baseline foresees a polarization-maintaining single-mode fiber for this backlink connection. Phase changes which are common in both directions do not enter the science measurement, but differential (‘non-reciprocal’) phase fluctuations directly do and must thus be guaranteed to be small enough. We have built a setup consisting of a Zerodur baseplate with fused silica components attached to it using hydroxide-catalysis bonding and demonstrated the reciprocity of a polarization-maintaining single-mode fiber at the 1 pm \\sqrt{Hz}-1 level as is required for LISA. We used balanced detection to reduce the influence of parasitic optical beams on the reciprocity measurement and a fiber length stabilization to avoid nonlinear effects in our phase measurement system (phase meter). For LISA, a different phase meter is planned to be used that does not show this nonlinearity. We corrected the influence of beam angle changes and temperature changes on the reciprocity measurement in post-processing.

  6. Automatic system for quantification and visualization of lung aeration on chest computed tomography images: the Lung Image System Analysis - LISA

    Energy Technology Data Exchange (ETDEWEB)

    Felix, John Hebert da Silva; Cortez, Paulo Cesar, E-mail: jhsfelix@gmail.co [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Dept. de Engenharia de Teleinformatica; Holanda, Marcelo Alcantara [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Hospital Universitario Walter Cantidio. Dept. de Medicina Clinica

    2010-12-15

    High Resolution Computed Tomography (HRCT) is the exam of choice for the diagnostic evaluation of lung parenchyma diseases. There is an increasing interest for computational systems able to automatically analyze the radiological densities of the lungs in CT images. The main objective of this study is to present a system for the automatic quantification and visualization of the lung aeration in HRCT images of different degrees of aeration, called Lung Image System Analysis (LISA). The secondary objective is to compare LISA to the Osiris system and also to specific algorithm lung segmentation (ALS), on the accuracy of the lungs segmentation. The LISA system automatically extracts the following image attributes: lungs perimeter, cross sectional area, volume, the radiological densities histograms, the mean lung density (MLD) in Hounsfield units (HU), the relative area of the lungs with voxels with density values lower than -950 HU (RA950) and the 15th percentile of the least density voxels (PERC15). Furthermore, LISA has a colored mask algorithm that applies pseudo-colors to the lung parenchyma according to the pre-defined radiological density chosen by the system user. The lungs segmentations of 102 images of 8 healthy volunteers and 141 images of 11 patients with Chronic Obstructive Pulmonary Disease (COPD) were compared on the accuracy and concordance among the three methods. The LISA was more effective on lungs segmentation than the other two methods. LISA's color mask tool improves the spatial visualization of the degrees of lung aeration and the various attributes of the image that can be extracted may help physicians and researchers to better assess lung aeration both quantitatively and qualitatively. LISA may have important clinical and research applications on the assessment of global and regional lung aeration and therefore deserves further developments and validation studies. (author)

  7. Automatic system for quantification and visualization of lung aeration on chest computed tomography images: the Lung Image System Analysis - LISA

    International Nuclear Information System (INIS)

    Felix, John Hebert da Silva; Cortez, Paulo Cesar; Holanda, Marcelo Alcantara

    2010-01-01

    High Resolution Computed Tomography (HRCT) is the exam of choice for the diagnostic evaluation of lung parenchyma diseases. There is an increasing interest for computational systems able to automatically analyze the radiological densities of the lungs in CT images. The main objective of this study is to present a system for the automatic quantification and visualization of the lung aeration in HRCT images of different degrees of aeration, called Lung Image System Analysis (LISA). The secondary objective is to compare LISA to the Osiris system and also to specific algorithm lung segmentation (ALS), on the accuracy of the lungs segmentation. The LISA system automatically extracts the following image attributes: lungs perimeter, cross sectional area, volume, the radiological densities histograms, the mean lung density (MLD) in Hounsfield units (HU), the relative area of the lungs with voxels with density values lower than -950 HU (RA950) and the 15th percentile of the least density voxels (PERC15). Furthermore, LISA has a colored mask algorithm that applies pseudo-colors to the lung parenchyma according to the pre-defined radiological density chosen by the system user. The lungs segmentations of 102 images of 8 healthy volunteers and 141 images of 11 patients with Chronic Obstructive Pulmonary Disease (COPD) were compared on the accuracy and concordance among the three methods. The LISA was more effective on lungs segmentation than the other two methods. LISA's color mask tool improves the spatial visualization of the degrees of lung aeration and the various attributes of the image that can be extracted may help physicians and researchers to better assess lung aeration both quantitatively and qualitatively. LISA may have important clinical and research applications on the assessment of global and regional lung aeration and therefore deserves further developments and validation studies. (author)

  8. Non-linear quantization error reduction for the temperature measurement subsystem on-board LISA Pathfinder

    Science.gov (United States)

    Sanjuan, J.; Nofrarias, M.

    2018-04-01

    Laser Interferometer Space Antenna (LISA) Pathfinder is a mission to test the technology enabling gravitational wave detection in space and to demonstrate that sub-femto-g free fall levels are possible. To do so, the distance between two free falling test masses is measured to unprecedented sensitivity by means of laser interferometry. Temperature fluctuations are one of the noise sources limiting the free fall accuracy and the interferometer performance and need to be known at the ˜10 μK Hz-1/2 level in the sub-millihertz frequency range in order to validate the noise models for the future space-based gravitational wave detector LISA. The temperature measurement subsystem on LISA Pathfinder is in charge of monitoring the thermal environment at key locations with noise levels of 7.5 μK Hz-1/2 at the sub-millihertz. However, its performance worsens by one to two orders of magnitude when slowly changing temperatures are measured due to errors introduced by analog-to-digital converter non-linearities. In this paper, we present a method to reduce this effect by data post-processing. The method is applied to experimental data available from on-ground validation tests to demonstrate its performance and the potential benefit for in-flight data. The analog-to-digital converter effects are reduced by a factor between three and six in the frequencies where the errors play an important role. An average 2.7 fold noise reduction is demonstrated in the 0.3 mHz-2 mHz band.

  9. Modulator noise suppression in the LISA time-delay interferometric combinations

    International Nuclear Information System (INIS)

    Tinto, Massimo; Armstrong, J W; Estabrook, Frank B

    2008-01-01

    Laser Interferometer Space Antenna (LISA) is a mission to detect and study low-frequency cosmic gravitational radiation through its influence on the phases of six modulated laser beams exchanged between three remote spacecraft. We previously showed how the measurements of some 18 time series of relative frequency or phase shifts could be combined (1) to cancel the phase noise of the lasers, (2) to cancel the Doppler fluctuations due to non-inertial motions of the six optical benches and (3) to remove the phase noise of the onboard reference oscillators required to track the photodetector fringes, all the while preserving signals from passing gravitational waves. Here we analyze the effect of the additional noise due to the optical modulators used for removing the phase fluctuations of the onboard reference oscillators. We use the recently measured noise spectrum of an individual modulator (Klipstein et al 2006 Proc. 6th Int. LISA Symp. (Greenbelt, MA) (AIP Conf. Proc. vol 873) ed S M Merkowitz and J C Livas pp 19-23) to quantify the contribution of modulator noise to the first and second-generation time-delay interferometric (TDI) combinations as a function of the modulation frequency. We show that modulator noise can be made smaller than the expected proof-mass acceleration and optical-path noises if the modulation frequencies are larger than ∼682 MHz in the case of the unequal-arm Michelson TDI combination X 1 , ∼ 1.08 GHz for the Sagnac TDI combination α 1 , and ∼706 MHz for the symmetrical Sagnac TDI combination ζ 1 . These modulation frequencies are substantially smaller than previously estimated and may lead to less stringent requirements on the LISA's oscillator noise calibration subsystem. The measurements in Klipstein et al were performed in a laboratory experiment for a range of modulation frequencies, but we emphasize that, for the reference oscillator noise calibration algorithm to work, the modulation frequencies must be equal to the

  10. Massive Black Hole Mergers: Can We "See" what LISA will "Hear"?

    Science.gov (United States)

    Centrella, Joan

    2010-01-01

    The final merger of massive black holes produces strong gravitational radiation that can be detected by the space-borne LISA. If the black hole merger takes place in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Modeling such electromagnetic counterparts of the final merger requires evolving the behavior of both gas and fields in the strong-field regions around the black holes. We will review current efforts to simulate these systems, and discuss possibilities for observing the electromagnetic signals they produce.

  11. LISA - a powerful program package for LIstmode and Spectral data Analysis

    International Nuclear Information System (INIS)

    Oberstedt, A.; Hambsch, F.J.

    1994-01-01

    LISA is a graphical program package which enables both off-line listmode and spectral data evaluation as well as on-line monitoring while multi-parameter experiments are running. It can be executed on every computer with a UNIX operating system and an X-WINDOW environment, running PV-WAVE from Visual Numerics Incorporation. This package is basically written in the language PV-WAVE CL, but integration of procedures written in the C-language and execution of UNIX shell commands lead to an additional increase of performance. (orig.)

  12. On-orbit alignment and diagnostics for the LISA Technology Package

    International Nuclear Information System (INIS)

    MarIn, A F GarcIa; Wand, V; Steier, F; Cervantes, F Guzman; Bogenstahl, J; Jennrich, O; Heinzel, G; Danzmann, K

    2006-01-01

    This paper presents a procedure to perform fully autonomous on-orbit alignment of the interferometer on board the LISA Technology Package (LTP). LTP comprises two free-floating test masses as inertial sensors that additionally serve as end mirrors of a set of interferometers. From the output signals of the interferometers, a subset has been selected to obtain alignment information of the test masses. Based on these signals, an alignment procedure was developed and successfully tested on the engineering model of the optical bench. Furthermore, operation procedures for the characterization of critical on-orbit properties of the optical metrology system (e.g. fibre noise) have been established

  13. After-dinner speech: the path of LISA to become ‘L3’

    Science.gov (United States)

    Huber, M. C. E.

    2017-05-01

    We describe the state of fundamental-physics experiments in space in the mid 1980s on both sides of the Atlantic, and then follow the development of this field within ESA’s Scientific Programme. The special case of LISA — a fundamental physics experiment in space also supported by astronomers, and now, following the ground-based detection of gravitational waves, the means to extend the observable spectrum of such waves towards lower frequencies and long-lasting signals — is then followed in its rise to become the ‘Large Project L3’ of ESA.

  14. Observing extreme-mass-ratio inspirals with eLISA/NGO

    OpenAIRE

    Gair, Jonathan R; Porter, Edward K

    2012-01-01

    The extreme-mass-ratio inspirals (EMRIs) of stellar mass compact objects into massive black holes in the centres of galaxies are an important source of low-frequency gravitational waves for space-based detectors. We discuss the prospects for detecting these sources with the evolved Laser Interferometer Space Antenna (eLISA), recently proposed as an ESA mission candidate under the name NGO. We show that NGO could observe a few tens of EMRIs over its two year mission lifetime at redshifts z < 0...

  15. LISA. A code for safety assessment in nuclear waste disposals program description and user guide

    International Nuclear Information System (INIS)

    Saltelli, A.; Bertozzi, G.; Stanners, D.A.

    1984-01-01

    The code LISA (Long term Isolation Safety Assessment), developed at the Joint Research Centre, Ispra is a useful tool in the analysis of the hazard due to the disposal of nuclear waste in geological formations. The risk linked to preestablished release scenarios is assessed by the code in terms of dose rate to a maximum exposed individual. The various submodels in the code simulate the system of barriers -both natural and man made- which are interposed between the contaminants and man. After a description of the code features a guide for the user is supplied and then a test case is presented

  16. Effects of different eLISA-like configurations on massive black hole parameter estimation

    Science.gov (United States)

    Porter, Edward K.

    2015-09-01

    As the theme for the future L3 Cosmic Vision mission, ESA has recently chosen the "Gravitational Wave Universe." Within this program, a mission concept called eLISA has been proposed. This observatory has a current initial configuration consisting of four laser links between the three satellites, which are separated by a distance of one million kilometers, constructing a single-channel Michelson interferometer. However, the final configuration for the observatory will not be fixed until the end of this decade. With this in mind, we investigate the effect of different eLISA-like configurations on massive black hole detections. This work compares the results of a Bayesian inference study of 120 massive black hole binaries out to a redshift of z ˜13 for a 106 km arm length eLISA with four and six links, as well as a 2 ×106 km arm length observatory with four links. We demonstrate that the original eLISA configuration should allow us to recover the luminosity distance of the source with an error of less than 10% out to a redshift of z ˜4 , and a sky error box of Δ Ω ≤102 deg2 out to z ˜0.1 . In contrast, both alternative configurations suggest that we should be able to conduct the same parameter recovery with errors of less than 10% in luminosity distance out to z ˜12 and Δ Ω ≤102 deg2 out to z ˜0.4 . Using the information from these studies, we also infer that if we were able to construct a 2 Gm, six-link detector, the above values would shift to z ˜20 for luminosity distance and z ˜0.9 for sky error. While the final configuration will also be dependent on both technological and financial considerations, our study suggests that increasing the size of a two-arm detector is a viable alternative to the inclusion of a third arm in a smaller detector. More importantly, this work further suggests no clear scientific loss between either choice.

  17. Constraining early and interacting dark energy with gravitational wave standard sirens: the potential of the eLISA mission

    International Nuclear Information System (INIS)

    Caprini, Chiara; Tamanini, Nicola

    2016-01-01

    We perform a forecast analysis of the capability of the eLISA space-based interferometer to constrain models of early and interacting dark energy using gravitational wave standard sirens. We employ simulated catalogues of standard sirens given by merging massive black hole binaries visible by eLISA, with an electromagnetic counterpart detectable by future telescopes. We consider three-arms mission designs with arm length of 1, 2 and 5 million km, 5 years of mission duration and the best-level low frequency noise as recently tested by the LISA Pathfinder. Standard sirens with eLISA give access to an intermediate range of redshift 1 ∼< z ∼< 8, and can therefore provide competitive constraints on models where the onset of the deviation from ΛCDM (i.e. the epoch when early dark energy starts to be non-negligible, or when the interaction with dark matter begins) occurs relatively late, at z ∼< 6. If instead early or interacting dark energy is relevant already in the pre-recombination era, current cosmological probes (especially the cosmic microwave background) are more efficient than eLISA in constraining these models, except possibly in the interacting dark energy model if the energy exchange is proportional to the energy density of dark energy.

  18. Rapid prototyping and evaluation of programmable SIMD SDR processors in LISA

    Science.gov (United States)

    Chen, Ting; Liu, Hengzhu; Zhang, Botao; Liu, Dongpei

    2013-03-01

    With the development of international wireless communication standards, there is an increase in computational requirement for baseband signal processors. Time-to-market pressure makes it impossible to completely redesign new processors for the evolving standards. Due to its high flexibility and low power, software defined radio (SDR) digital signal processors have been proposed as promising technology to replace traditional ASIC and FPGA fashions. In addition, there are large numbers of parallel data processed in computation-intensive functions, which fosters the development of single instruction multiple data (SIMD) architecture in SDR platform. So a new way must be found to prototype the SDR processors efficiently. In this paper we present a bit-and-cycle accurate model of programmable SIMD SDR processors in a machine description language LISA. LISA is a language for instruction set architecture which can gain rapid model at architectural level. In order to evaluate the availability of our proposed processor, three common baseband functions, FFT, FIR digital filter and matrix multiplication have been mapped on the SDR platform. Analytical results showed that the SDR processor achieved the maximum of 47.1% performance boost relative to the opponent processor.

  19. Compact laser interferometer for translation and tilt measurement as optical readout for the LISA inertial sensor

    Science.gov (United States)

    Schuldt, Thilo; Gohlke, Martin; Weise, Dennis; Johann, Ulrich; Peters, Achim; Braxmaier, Claus

    2007-10-01

    The space mission LISA (Laser Interferometer Space Antenna) aims at detecting gravitational waves in the frequency range 30 μ Hz to 1Hz. Free flying proof masses inside the satellites act as inertial sensors and represent the end mirrors of the interferometer. In the current baseline design, LISA utilizes an optical readout of the position and tilt of the proof mass with respect to the satellite housing. This readout must have ~ 5pm/√Hz sensitivity for the translation measurement (for frequencies above 2.8mHz with an ƒ -2 relaxation down to 30 μHz) and ~ 10 nrad/√Hz sensitivity for the tilt measurement (for frequencies above 0.1mHz with an ƒ -1 relaxation down to 30 μHz). The University of Applied Sciences Konstanz (HTWG) - in collaboration with Astrium GmbH, Friedrichshafen, and the Humboldt-University Berlin - therefore develops a highly symmetric heterodyne interferometer implementing differential wavefront sensing for the tilt measurement. We realized a mechanically highly stable and compact setup. In a second, improved setup we measured initial noise levels below 5 pm/√Hz and 10 nrad/√Hz, respectively, for frequencies above 10mHz.

  20. Principles, operations, and expected performance of the LISA Pathfinder charge management system

    Energy Technology Data Exchange (ETDEWEB)

    Ziegler, T [Astrium GmbH, 88039 Friedrichshafen (Germany); Fichter, W [iFR, Universitaet Stuttgart, Pfaffenwaldring 7a, 70569 Stuttgart (Germany); Schulte, M [Blackett Laboratory, Imperial College, Prince Consort Road, London SW7 2BZ (United Kingdom); Vitale, S, E-mail: tobias.ziegler@astrium.eads.ne [Department of Physics, University of Trento, 38050 Povo, Trento (Italy)

    2009-03-01

    The test masses of LISA Pathfinder are free flying and therefore not grounded to the spacecraft by a wire. Because of galactic cosmic rays, solar energetic particles, and unknown microscopic surface effects during initial test mass release, an unacceptable level of absolute charge might be present on the test masses. A charged test mass can endanger transition to high accuracy control modes which are required for science experiments. Furthermore, charged test masses introduce unwanted disturbance accelerations for example due to Coulomb interactions with surrounding conducting surfaces. The charge management system is designed to discharge the test masses up to a tolerable level of absolute charge such that the mission goal can be achieved. It is therefore an essential part of the experiments to be performed with the LISA Technology Package. The paper describes charge management tasks to be performed on board the spacecraft and summarizes the principles of charge measurement and discharge control. An overview of the experiment operations is given where the interconnection of operational charge management system modes and operational modes of the drag-free, suspension and attitude control system is considered. Simulated performance results are presented.

  1. LISA time-delay interferometry zero-signal solution: Geometrical properties

    International Nuclear Information System (INIS)

    Tinto, Massimo; Larson, Shane L.

    2004-01-01

    Time-delay interferometry (TDI) is the data processing technique needed for generating interferometric combinations of data measured by the multiple Doppler readouts available onboard the three Laser Interferometer Space Antenna (LISA) spacecraft. Within the space of all possible interferometric combinations TDI can generate, we have derived a specific combination that has zero response to the gravitational wave signal, and called it the zero-signal solution (ZSS). This is a two-parameter family of linear combinations of the generators of the TDI space, and its response to a gravitational wave becomes null when these two parameters coincide with the values of the angles of the source location in the sky. Remarkably, the ZSS does not rely on any assumptions about the gravitational waveform, and in fact it works for waveforms of any kind. Our approach is analogous to the data analysis method introduced by Guersel and Tinto in the context of networks of Earth-based, wideband, interferometric gravitational wave detectors observing in coincidence a gravitational wave burst. The ZSS should be regarded as an application of the Guersel and Tinto method to the LISA data

  2. Metal-amplified Density Assays, (MADAs), including a Density-Linked Immunosorbent Assay (DeLISA).

    Science.gov (United States)

    Subramaniam, Anand Bala; Gonidec, Mathieu; Shapiro, Nathan D; Kresse, Kayleigh M; Whitesides, George M

    2015-02-21

    This paper reports the development of Metal-amplified Density Assays, or MADAs - a method of conducting quantitative or multiplexed assays, including immunoassays, by using Magnetic Levitation (MagLev) to measure metal-amplified changes in the density of beads labeled with biomolecules. The binding of target analytes (i.e. proteins, antibodies, antigens) to complementary ligands immobilized on the surface of the beads, followed by a chemical amplification of the binding in a form that results in a change in the density of the beads (achieved by using gold nanoparticle-labeled biomolecules, and electroless deposition of gold or silver), translates analyte binding events into changes in density measureable using MagLev. A minimal model based on diffusion-limited growth of hemispherical nuclei on a surface reproduces the dynamics of the assay. A MADA - when performed with antigens and antibodies - is called a Density-Linked Immunosorbent Assay, or DeLISA. Two immunoassays provided a proof of principle: a competitive quantification of the concentration of neomycin in whole milk, and a multiplexed detection of antibodies against Hepatitis C virus NS3 protein and syphilis T. pallidum p47 protein in serum. MADAs, including DeLISAs, require, besides the requisite biomolecules and amplification reagents, minimal specialized equipment (two permanent magnets, a ruler or a capillary with calibrated length markings) and no electrical power to obtain a quantitative readout of analyte concentration. With further development, the method may be useful in resource-limited or point-of-care settings.

  3. Parasites and hepatic histopathological lesions in lisa (Mugil incilis from Totumo mash, North of Colombia

    Directory of Open Access Journals (Sweden)

    Jesús Olivero V.

    2013-03-01

    Full Text Available Objective. To assess the levels of parasitism by nematodes and trematodes, as well as the hepatic histopathological alterations present in Mugil incilis (Lisa from Totumo marsh, North of Colombia. Materials and methods. Between July 2004 and June 2005, 500 fish were collected at Totumo Marsh (75°16’W and 10°44´N, North of Colombia. Morphometric and parasitic parameters were determined for each specimen, and the hepatic histopathological status of the liver was assessed by analyzing liver slides stained with hematoxylin and eosin. Results. Nematode larvae isolated from Mugil incilis corresponded to Contracaecum spp. Parasite prevalence was 60.49%. Parasitic mean abundance and mean intensity were 4.8±1.05 and 7.02±1.49, nematodes per fish, respectively. The correlation between nematode mean abundance and fish length was significant and positive (r=0.525, p<0.0001, but negative for condition factor (r=-0.109, p=0.014. Hepatic histopathological analysis revealed the presence of encapsulated trematode larvae as the main finding. However, the presence of inflammation, granulomas, steatosis and necrosis, were also registered as secondary alterations. Conclusions. Lisas collected at Totumo Marsh are parasitized with nematodes and trematodes. These fish have different histopathological lesions in the liver tissue, being the most important the presence of trematode encapsulated cyst that generate inflammatory reactions, and negatively correlate with morphometric markers of fish health.

  4. Constraints on LISA Pathfinder's Self-Gravity: Design Requirements, Estimates and Testing Procedures

    Science.gov (United States)

    Armano, M.; Audley, H.; Auger, G.; Baird, J.; Binetruy, P.; Born, M.; Bortoluzzi, M.; Brandt, Nico; Bursi, Alessandro; Slutsky. J.; hide

    2016-01-01

    LISA Pathfinder satellite was launched on 3 December 2015 toward the Sun Earth first Lagrangian point (L1) where the LISA Technology Package (LTP), which is the main science payload, will be tested. LTP achieves measurements of differential acceleration of free-falling test masses (TMs) with sensitivity below 3 x 10(exp -14) m s(exp -2) Hz(exp - 1/2) within the 130 mHz frequency band in one dimension. The spacecraft itself is responsible for the dominant differential gravitational field acting on the two TMs. Such a force interaction could contribute a significant amount of noise and thus threaten the achievement of the targeted free-fall level. We prevented this by balancing the gravitational forces to the sub nm s(exp -2) level, guided by a protocol based on measurements of the position and the mass of all parts that constitute the satellite, via finite element calculation tool estimates. In this paper, we will introduce the gravitational balance requirements and design, and then discuss our predictions for the balance that will be achieved in flight.

  5. Simulation of the charging process of the LISA test masses due to solar flares

    International Nuclear Information System (INIS)

    Vocca, H; Grimani, C; Amico, P; Bosi, L; Marchesoni, F; Punturo, M; Travasso, F; Barone, M; Stanga, R; Vetrano, F; Vicere, A

    2004-01-01

    Cosmic-ray and solar high energy particles penetrate the LISA experiment test masses. Consequently, an electric charge accumulates in the bodies of the masses, generating spurious Coulomb forces between the masses and the surrounding electrodes. This process increases the noise level of the experiment. We have estimated the amount of charge deposited per second on the LISA test masses by solar flares and primary cosmic-ray protons at solar minimum. The simulation has been carried out with the Fluka Monte Carlo program. A simplified geometry for the experiment has been considered. We have found a net charging rate of 37 ± 1 e + /s for primary protons at solar minimum between 0.1 and 1000 GeV/n. The amount of charge released by a medium-strong solar flare, like that of 16 February 1984, is 10 732 ± 30 e + /s in the energy range 0.1-10 GeV/n. This value increases or decreases by approximately one order of magnitude for strong (weak) solar flares

  6. Science with the space-based interferometer eLISA. II. Gravitational waves from cosmological phase transitions

    International Nuclear Information System (INIS)

    Caprini, Chiara; Hindmarsh, Mark; Helsinki Univ.; Huber, Stephan

    2016-04-01

    We investigate the potential for the eLISA space-based interferometer to detect the stochastic gravitational wave background produced by strong first-order cosmological phase transitions. We discuss the resulting contributions from bubble collisions, magnetohydrodynamic turbulence, and sound waves to the stochastic background, and estimate the total corresponding signal predicted in gravitational waves. The projected sensitivity of eLISA to cosmological phase transitions is computed in a model-independent way for various detector designs and configurations. By applying these results to several specific models, we demonstrate that eLISA is able to probe many well-motivated scenarios beyond the Standard Model of particle physics predicting strong first-order cosmological phase transitions in the early Universe.

  7. EDITORIAL: Proceedings of the 7th International LISA Symposium, Barcelona, Spain, 16-20 June 2008 Proceedings of the 7th International LISA Symposium, Barcelona, Spain, 16-20 June 2008

    Science.gov (United States)

    Lobo, Alberto; Sopuerta, Carlos F.

    2009-05-01

    In June 2006 the LISA International Science Team (LIST) accepted the bid presented by the Institut d'Estudis Espacials de Catalunya (IEEC) to host the 7th International LISA Symposium. This was during its 11th meeting at the University of Maryland, just before the 6th edition of the symposium started at NASA's Goddard Space Flight Center. The 7th International LISA Symposium took place in the city of Barcelona, Spain, 16-20 June, 2008, in the premises of CosmoCaixa, a modern science museum located in the hills near Tibidabo. Almost 240 delegates registered for the event, a record breaking figure compared to previous editions of the symposium. Many of the most renowned world experts in LISA, gravitational wave science, and astronomy, as well as engineers, attended LISA #7 and produced state of the art presentations, while everybody benefited from the opportunity to have live discussions during the week in a friendly environment. The programme included 31 invited plenary lectures in the mornings, and eight parallel sessions in the afternoons. These were classified into seven major areas of research: LISA Technology, LISA PathFinder, LISA PathFinder Data Analysis, LISA Data Analysis, Gravitational Wave Sources, Cosmology and Fundamental Physics with LISA and Other Gravitational Wave Detectors. Abstracts for 138 communications were received, from which a selection was made by the session convenors which would fit time constraints. Up to 63 posters completed the scientific programme. More details on the programme, including some of the talks, can be found at the symposium website:http://www.ice.cat/research/LISA_Symposium. There was, however, a remarkable add-on: Professor Clifford Will delivered a startling presentation to the general public, who completely filled the Auditori—the main conference room, 320 seats—and were invited to ask questions to the speaker who boldly guided them through the daunting world of Black Holes, Waves of Gravity, and other Warped Ideas

  8. The low emittance 2.5 GeV synchrotron light source LISA

    International Nuclear Information System (INIS)

    Einfeld, D.; Hormes, J.; Husmann, D.

    1992-01-01

    LISA, a Light source for Industrial and Scientific Applications, has been proposed. Due to the intention to use the source above all for the LIGA (Lithographie, Galvanik, Abformtechnik) method to produce micromechanical structures, the critical wavelength of the synchrotron radiation spectrum is foreseen to be 0.2 nm. Therefore, the electron energy and the field strength of the ring dipoles have been chosen to be 2.5 GeV and 1.5 T, respectively. It is proposed to make use of a modified 'quadrupole ben achromat' (QBA) lattice. The novel feature of this lattice is the application of two types of bending magnets of different lengths, i.e. different bending angels. (author) 9 refs.; 6 figs.; 1 tab

  9. Metaphors Expressing Emotions in Lisa Kleypas’s Rainshadow Road Novel

    Directory of Open Access Journals (Sweden)

    Novi Liana Ko

    2014-05-01

    Full Text Available Metaphors have been always interesting to explore since they are able to represent many things, one of which is feelings. Article examined the metaphorical sentences which expressed emotions found in Lisa Kleypas’s the Rainshadow Road. Library research was conducted to find the kinds of emotions which were expressed by the metaphorical sentences. It was also done to figure out what the metaphors refered to. Another objective was to reveal the most dominant emotion which appeared through the metaphors expressed in the novel. The analysis used metaphor theory to compare the dictionary meaning and the metaphorical one. The result shows that there are various emotions which are expressed through the metaphorical sentences. Happiness is found as the most dominant emotion which appears in the novel.

  10. Actuation stability test of the LISA pathfinder inertial sensor front-end electronics

    Science.gov (United States)

    Mance, Davor; Gan, Li; Weber, Bill; Weber, Franz; Zweifel, Peter

    In order to limit the residual stray forces on the inertial sensor test mass in LISA pathfinder, √ it is required that the fluctuation of the test mass actuation voltage is within 2ppm/ Hz. The actuation voltage stability test on the flight hardware of the inertial sensor front-end electronics (IS FEE) is presented in this paper. This test is completed during the inertial sensor integration at EADS Astrium Friedrichshafen, Germany. The standard measurement method using voltmeter is not sufficient for verification, since the instrument low frequency √ fluctuation is higher than the 2ppm/ Hz requirement. In this test, by using the differential measurement method and the lock-in amplifier, the actuation stability performance is verified and the quality of the IS FEE hardware is confirmed by the test results.

  11. Inference on white dwarf binary systems using the first round Mock LISA Data Challenges data sets

    International Nuclear Information System (INIS)

    Stroeer, Alexander; Veitch, John; Roever, Christian; Bloomer, Ed; Clark, James; Christensen, Nelson; Hendry, Martin; Messenger, Chris; Meyer, Renate; Pitkin, Matthew; Toher, Jennifer; Umstaetter, Richard; Vecchio, Alberto; Woan, Graham

    2007-01-01

    We report on the analysis of selected single source data sets from the first round of the mock LISA data challenges (MLDC) for white dwarf binaries. We implemented an end-to-end pipeline consisting of a grid-based coherent pre-processing unit for signal detection and an automatic Markov Chain Monte Carlo (MCMC) post-processing unit for signal evaluation. We demonstrate that signal detection with our coherent approach is secure and accurate, and is increased in accuracy and supplemented with additional information on the signal parameters by our Markov Chain Monte Carlo approach. We also demonstrate that the Markov Chain Monte Carlo routine is additionally able to determine accurately the noise level in the frequency window of interest

  12. Auxiliary functions of the LISA laser link: ranging, clock noise transfer and data communication

    International Nuclear Information System (INIS)

    Heinzel, Gerhard; Esteban, Juan Jose; Barke, Simon; Otto, Markus; Wang Yan; Garcia, Antonio F; Danzmann, Karsten

    2011-01-01

    The Laser Interferometer Space Antenna (LISA) is required to reduce two important noise sources by post-processing on the ground using time-delay interferometry (TDI): phase noise of the on-board reference clocks and laser frequency noise. To achieve the desired suppression, the TDI algorithm needs measurements of the differential clock noise between any two spacecraft and inter-spacecraft ranging measurements with at least 1 m accuracy, which is beyond the precision of ground-based measurements for deep space missions. Therefore, we need on-board measurements by transmitting clock noise and ranging information between the spacecraft as auxiliary functions of the laser link. This paper reports our current experimental results in clock noise transfer and ranging for noise subtraction via post-processing as well as additional data transfer.

  13. Massive Black Hole Mergers: Can we see what LISA will hear?

    Science.gov (United States)

    Centrella, Joan

    2009-01-01

    Coalescing massive black hole binaries are formed when galaxies merge. The final stages of this coalescence produce strong gravitational wave signals that can be detected by the space-borne LISA. When the black holes merge in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Modeling such electromagnetic counterparts requires evolving the behavior of both gas and fields in the strong-field regions around the black holes. We have taken a first step towards this problem by mapping the flow of pressureless matter in the dynamic, 3-D general relativistic spacetime around the merging black holes. We report on the results of these initial simulations and discuss their likely importance for future hydrodynamical simulations.

  14. eLISA Telescope In-field Pointing and Scattered Light Study

    Science.gov (United States)

    Livas, J.; Sankar, S.; West, G.; Seals, L.; Howard, J.; Fitzsimons, E.

    2017-05-01

    The orbital motion of the three spacecraft that make up the eLISA Observatory constellation causes long-arm line of sight variations of approximately ± one degree over the course of a year. The baseline solution is to package the telescope, the optical bench, and the gravitational reference sensor (GRS) into an optical assembly at each end of the measurement arm, and then to articulate the assembly. An optical phase reference is exchanged between the moving optical benches with a single mode optical fiber (“backlink” fiber). An alternative solution, referred to as in-field pointing, embeds a steering mirror into the optical design, fixing the optical benches and eliminating the backlink fiber, but requiring the additional complication of a two-stage optical design for the telescope. We examine the impact of an in-field pointing design on the scattered light performance.

  15. A constrained Metropolis-Hastings search for EMRIs in the Mock LISA Data Challenge 1B

    International Nuclear Information System (INIS)

    Gair, Jonathan R; Porter, Edward; Babak, Stanislav; Barack, Leor

    2008-01-01

    We describe a search for the extreme-mass-ratio inspiral sources in the Round 1B Mock LISA Data Challenge data sets. The search algorithm is a Monte Carlo search based on the Metropolis-Hastings algorithm, but also incorporates simulated, thermostated and time annealing, plus a harmonic identification stage designed to reduce the chance of the chain locking onto secondary maxima. In this paper, we focus on describing the algorithm that we have been developing. We give the results of the search of the Round 1B data, although parameter recovery has improved since that deadline. Finally, we describe several modifications to the search pipeline that we are currently investigating for incorporation in future searches

  16. Bell's palsy: the answer to the riddle of Leonardo da Vinci's 'Mona Lisa'.

    Science.gov (United States)

    Maloney, W J

    2011-05-01

    The smile of the famed portrait 'The Mona Lisa' has perplexed both art historians and researchers for the past 500 years. There has been a multitude of theories expounded to explain the nature of the model's enigmatic smile. The origin of the model's wry smile can be demonstrated through a careful analysis of both documented facts concerning the portrait--some gathered only recently through the use of modern technology--and a knowledge of the clinical presentation of Bell's palsy. Bell's palsy is more prevalent in women who are either pregnant or who have recently given birth. This paper postulates that the smile of the portrait's model was due to Leonardo da Vinci's anatomically precise representation of a new mother affected by Bell's palsy subsequent to her recent pregnancy.

  17. Selective metallization of polymers using laser induced surface activation (LISA)—characterization and optimization of porous surface topography

    DEFF Research Database (Denmark)

    Zhang, Yang; Hansen, Hans Nørgaard; De Grave, Arnaud

    2011-01-01

    Laser induced selective activation (LISA) is a molded interconnected devices technique for selective metallization of polymers. On the working piece, only the laser-machined area can be metalized in the subsequent plating. The principle of the technology is introduced. Surface analysis was perfor...

  18. Simple Enough--Even for Web Virgins: Lisa Mitten's Access to Native American Web Sites. Web Site Review Essay.

    Science.gov (United States)

    Belgarde, Mary Jiron

    1998-01-01

    A mixed-blood Mohawk urban Indian and university librarian, Lisa Mitten provides access to Web sites with solid information about American Indians. Links are provided to 10 categories--Native nations, Native organizations, Indian education, Native media, powwows and festivals, Indian music, Native arts, Native businesses, and Indian-oriented home…

  19. Search for a stochastic gravitational-wave signal in the second round of the Mock LISA Data Challenges

    International Nuclear Information System (INIS)

    Robinson, E L; Vecchio, A; Romano, J D

    2008-01-01

    The analysis method currently proposed to search for isotropic stochastic radiation with the Laser Interferometer Space Antenna (LISA) relies on the combined use of two LISA channels, one of which is insensitive to gravitational waves, such as the symmetrized Sagnac. For this method to work, it is essential to know how the instrumental noise power in the two channels are related to one another; however, no quantitative estimates of this key information are available to date. The purpose of our study is to assess the performance of the symmetrized Sagnac method for different levels of prior information regarding the instrumental noise. We develop a general approach in the framework of Bayesian inference and an end-to-end analysis algorithm based on Markov chain Monte Carlo methods to compute the posterior probability density functions of the relevant model parameters. We apply this method to data released as part of the second round of the Mock LISA Data Challenges. For the selected (and somewhat idealized) example cases considered here, we find that for a signal whose amplitude dominates the instrumental noise by a factor ∼25, a prior uncertainty of a factor ∼2 in the ratio between the power of the instrumental noise contributions in the two channels allows for the detection of isotropic stochastic radiation. More importantly, we provide a framework for more realistic studies of LISA's performance and development of analysis techniques in the context of searches for stochastic signals

  20. Playing Harry Potter: Essays and interviews on fandom and performance, edited by Lisa S. Brenner [book review

    Directory of Open Access Journals (Sweden)

    Abigail De Kosnik

    2016-09-01

    Full Text Available Review of Lisa S. Brenner, editor. Playing Harry Potter: Essays and interviews on fandom and performance. Jefferson, NC: McFarland, 2015, paperback, $29.95 (238p ISBN 978-0-7864-9657-0, e-book $14.43 (5374 KB ISBN 978-1-4766-2136-4, ASIN B012E9G0R6.

  1. Elimination of vibrio cholerae in lisa fillets (Mugil cephalus) by gamma radiation

    International Nuclear Information System (INIS)

    Torres, Z.

    1999-03-01

    The elimination of Vibrio cholerae 01 biotype El Tor (1,87 8 cuf/g) in fresh lisa fillets (Mugil cephalus) with radiation doses of 0 and 0,5 kGy was investigated. Furthermore, in order to evaluate physical, chemical and sensory changes, doses of 1,2,3 and 4 kGy were applied to non inoculated fillets of lisa. Finally, D 10 for Vibrio cholerae was determined in a saline suspension (5,2x10 8 cfu/ml) based on the Most Probable Number (MPN) method and radiation doses of 0,5, 0,75, 1,0, 1,25 and 1,5 kGy. D value found in a 1,87 8 cfu/g concentration of fillet was 0,13 kGy. Humidity, protein, fat and ash contents were not affected significantly and remained around 73 to 75,5, 3,8 to 4,2 and 1% respectively. Control samples showed a 'drip' variation ranging between 0,82 and 0,88% and a N-BVT variation between 1,77 and 1,56, 0,89 and 1,99, 2,13 and 2,47, 1,86 and 2,10%, and a N-BVT variation between 17,79 and 30,16, 16,37 and 26,88 16,33 and 25,12, 15,31 and 33,54 mg N/100 g, respectively. The highest life span for the appearance characteristic was obtained by control samples (23 days) and the lowest by samples radiated at 3 and 4 kGy (28 days). 4 kGy dose resulted in organoleptic changes perceived by panelists during tasting of cooked fish. D 10 found in a saline suspension was 0,13 kGy

  2. Editorial. Special issue of Classical and Quantum Gravity on the proceedings of the 4th international LISA symposium

    International Nuclear Information System (INIS)

    Finn, Lee Samuel

    2003-01-01

    The 4th International LISA Symposium was held at the National Science Foundation Physics Frontier Center for Gravitational Wave Physics at The Pennsylvania State University on 19-24 July 2002. This special issue of Classical and Quantum Gravity is the proceedings of this meeting. LISA - the Laser Interferometer Space Antenna - is part of an international effort to open a new window on the universe. Not all things radiate light, but everything gravitates. Observations of the gravitational waves radiated by black holes and compact binary star systems, in our galaxy and beyond, can reveal details about these systems and their environments that are otherwise inaccessible. The international effort, of which LISA is a part, includes ground-based detectors, and the relationship between LISA and its ground-based detector 'cousins' was an important theme for this Symposium. LISA will observe gravitational waves in the 0.1 mHz to 0.1 Hz band, complementing observations made by ground-based detectors in the 10 Hz to several KHz band. Together they will explore nearly six decades of bandwidth in the gravitational-wave sky. LISA in particular will observe the gravitational waves radiated by the coalescence of black holes at the centres of colliding galaxies, and the inspiral of compact neutron stars or stellar-mass black holes onto these black holes, virtually anywhere in the universe. It will take a census of neutron star or close white dwarf binaries in our own galaxy and observe the formation of large black holes from the very first structures to form and collapse in our universe. In doing all these things, it will shed new 'light' on the first structures to form in the universe, explore the evolution of galaxies and the roles that black holes play in their structure, test relativity near the 'edges' of a black hole, and deepen our understanding of stellar and binary system evolution. A successful conference - and this LISA Symposium, like its predecessors, was very

  3. Optical metrology alignment and impact on the measurement performance of the LISA Technology Package

    Energy Technology Data Exchange (ETDEWEB)

    Hirth, M; Fichter, W; Brandt, N; Gerardi, D [iFR, Universitaet Stuttgart, Pfaffenwaldring 7a, 70569 Stuttgart (Germany); Schleicher, A [Astrium GmbH, 88039 Friedrichshafen (Germany); Wanner, G, E-mail: marc.hirth@ifr.uni-stuttgart.d [Albert Einstein Institut, Callinstrasse 38, 30167 Hannover (Germany)

    2009-03-01

    Aside from LISA Pathfinder's top-level acceleration requirement, there is a stringent independent requirement for the accuracy of the optical metrology system. In case of a perfectly aligned metrology system (optical bench and test masses) it should rather be independent of residual displacement jitter due to control. However, this ideal case will not be achieved as mechanical tolerances and uncertainties lead to a direct impact of test mass and spacecraft displacement jitter on the optical measurement accuracy. In this paper, we present a strategy how to cover these effects for a systematic requirement breakdown. We use a simplified nonlinear geometrical model for the differential distance measurement of the test masses which is linearized and linked to the equations of motion for both the spacecraft and the two test masses. This leads from test mass relative displacement to a formulation in terms of applied force/torque and thus allows to distinguish the absolute motion of each of the three bodies. It further shows how motions in each degree of freedom couple linearly into the optical measurement via DC misalignments of the laser beam and the test masses. This finally allows for deriving requirements on the alignment accuracy of components and on permittable closed-loop acceleration noise. In the last part a budget for the expected measurement performance is compiled from simulations as no measurement data is available yet.

  4. The late inspiral of supermassive black hole binaries with circumbinary gas discs in the LISA band

    Science.gov (United States)

    Tang, Yike; Haiman, Zoltán; MacFadyen, Andrew

    2018-05-01

    We present the results of 2D, moving-mesh, viscous hydrodynamical simulations of an accretion disc around a merging supermassive black hole binary (SMBHB). The simulation is pseudo-Newtonian, with the BHs modelled as point masses with a Paczynski-Wiita potential, and includes viscous heating, shock heating, and radiative cooling. We follow the gravitational inspiral of an equal-mass binary with a component mass Mbh = 106 M⊙ from an initial separation of 60rg (where rg ≡ GMbh/c2 is the gravitational radius) to the merger. We find that a central, low-density cavity forms around the binary, as in previous work, but that the BHs capture gas from the circumbinary disc and accrete efficiently via their own minidiscs, well after their inspiral outpaces the viscous evolution of the disc. The system remains luminous, displaying strong periodicity at twice the binary orbital frequency throughout the entire inspiral process, all the way to the merger. In the soft X-ray band, the thermal emission is dominated by the inner edge of the circumbinary disc with especially clear periodicity in the early inspiral. By comparison, harder X-ray emission is dominated by the minidiscs, and the light curve is initially more noisy but develops a clear periodicity in the late inspiral stage. This variability pattern should help identify the electromagnetic counterparts of SMBHBs detected by the space-based gravitational-wave detector LISA.

  5. Optical metrology alignment and impact on the measurement performance of the LISA Technology Package

    International Nuclear Information System (INIS)

    Hirth, M; Fichter, W; Brandt, N; Gerardi, D; Schleicher, A; Wanner, G

    2009-01-01

    Aside from LISA Pathfinder's top-level acceleration requirement, there is a stringent independent requirement for the accuracy of the optical metrology system. In case of a perfectly aligned metrology system (optical bench and test masses) it should rather be independent of residual displacement jitter due to control. However, this ideal case will not be achieved as mechanical tolerances and uncertainties lead to a direct impact of test mass and spacecraft displacement jitter on the optical measurement accuracy. In this paper, we present a strategy how to cover these effects for a systematic requirement breakdown. We use a simplified nonlinear geometrical model for the differential distance measurement of the test masses which is linearized and linked to the equations of motion for both the spacecraft and the two test masses. This leads from test mass relative displacement to a formulation in terms of applied force/torque and thus allows to distinguish the absolute motion of each of the three bodies. It further shows how motions in each degree of freedom couple linearly into the optical measurement via DC misalignments of the laser beam and the test masses. This finally allows for deriving requirements on the alignment accuracy of components and on permittable closed-loop acceleration noise. In the last part a budget for the expected measurement performance is compiled from simulations as no measurement data is available yet.

  6. Picometer stable scan mechanism for gravitational wave detection in space: LISA PAAM

    Science.gov (United States)

    Pijnenburg, J. A. C. M.; Rijnveld, N.

    2017-11-01

    Detection and observation of gravitational waves requires extreme stability in the frequency range 0.03 mHz to 1 Hz. The Laser Interferometer Space Antenna (LISA) mission will attain this by creating a giant interferometer in space, based on free floating proof masses in three spacecrafts. Due to orbit evolution and time delay in the interferometer arms, the direction of transmitted light changes. To solve this problem, a picometer stable Point-Ahead Angle Mechanism (PAAM) was designed, realized and successfully tested. The PAAM concept is based on a rotatable mirror. The critical requirements are the contribution to the optical path length (less than 1.4 pm / rt Hz) and the angular jitter (less than 8 nrad / rt Hz). Extreme dimensional stability is achieved by manufacturing a monolithical Haberland hinge mechanism out of Ti6Al4V, through high precision wire erosion. Extreme thermal stability is realized by placing the thermal center on the surface of the mirror. Because of piezo actuator noise and leakage, the PAAM has to be controlled in closed-loop. To meet the requirements in the low frequencies, an active target capacitance-to-digital converter is used. Interferometric measurements with a triangular resonant cavity in vacuum proved that the PAAM meets the requirements.

  7. Testing and Characterization of a Prototype Telescope for the Evolved Laser Interferometer Space Antenna (eLISA)

    Science.gov (United States)

    Sankar, S.; Livas, J.

    2016-01-01

    We describe our efforts to fabricate, test and characterize a prototype telescope for the eLISA mission. Much of our work has centered on the modeling and measurement of scattered light performance. This work also builds on a previous demonstration of a high dimensional stability metering structure using particular choices of materials and interfaces. We will discuss ongoing plans to merge these two separate demonstrations into a single telescope design demonstrating both stray light and dimensional stability requirements simultaneously.

  8. The End of Panopticon/panopticism in William Gibson’s Mona Lisa Overdrive : A Baudrillardian Reading

    Directory of Open Access Journals (Sweden)

    Hanieh Zaltash

    2014-11-01

    Full Text Available This paper seeks to examine William Gibson’s Mona Lisa Overdrive as a cyberpunk novel in the light of Baudrillard’s theory of “Simulation”. Jean Baudrillard believes that reality is replaced by “hyperreality” and human beings live in a total “simulation” in which everything, such as power might be simulated. Thus, according to Baudrillard, power exists just as “the simulation of power” which is the result of “the circularization of power” between the dominator and the dominated. Baudrillard delineates “the circularization of power” through criticizing Michel Foucault’s theories regarding power and panopticon, and introduces “the end of panopticon” which is centered upon the reversibility of the positions of the observer and the observed. In a meticulous analysis of TV performance of the Loud family in 1971, Baudrillard claims that the panoptic system is ended through playing on the opposition of seeing and being seen. The findings suggest that Mona Lisa Overdrive depicts “the end of panopticon,” in a sense that Angie Mitchell in this novel can be considered as a counterpart for Baudrillard’s instance of the Loud family. Indeed, this study attempts to elucidate “the end of panopticon” in Mona Lisa Overdrive (1988 through scrutinizing Angie Mitchell’s way of living.

  9. Eventos adversos temporalmente asociados a VAMENGOC- BC®. Municipio La Lisa, 1998-1999

    Directory of Open Access Journals (Sweden)

    Iván Edelberto Cuevas

    2000-12-01

    Full Text Available Con el objetivo de describir la frecuencia de eventos temporalmente asociados a la vacuna cubana VAMENGOC- BC®, se realizó un estudio observacional de tipo descriptivo, cuyo universo estuvo constituido por los lactantes en las edades comprendidas de tres (3549 y cinco meses (3832 de edad de las áreas de salud del Municipio La Lisa en Ciudad de La Habana. Hubo un 3,21% de niños con eventos adversos, con una mayor frecuencia después de la primera dosis; sin diferencias apreciables por sexo. La clasificación fue de un 52% de tipo sistémico, locales un 19% y no solicitados un 29%. La mayor parte de los niños afectados fue en las primeras 72 horas posteriores a la vacunación, y desaparecieron antes de 72 horas desde su comienzo. Las manifestaciones más frecuentes fueron fiebre (predominó entre todos los eventos adversos con 1,53 casos por 100 vacunados; la induración (0,31 por 100 vacunados, eritema (0,30 por 100 vacunados y el dolor (0,136 por 100 vacunados en el sitio de administración de la vacuna; irritabilidad (0,244 por 100 vacunados y pérdida de apetito (0,311 por 100 vacunados. Los eventos no solicitados más frecuentes fueron la Enfermedad Respiratoria Aguda (0,637 por 100 vacunados, la Enfermedad Diarreica Aguda (0,311 por 100 vacunados y la Otitis Media (0,176 por 100 vacunados. Los eventos adversos serios fueron infrecuentes. No hubo fallecidos y todos los casos se recuperaron en menos de diez días, sin secuelas, discapacidades ni minusvalías

  10. Coupling of relative intensity noise and pathlength noise to the length measurement in the optical metrology system of LISA Pathfinder

    Science.gov (United States)

    Wittchen, Andreas; the LPF Collaboration

    2017-05-01

    LISA Pathfinder is a technology demonstration mission for the space-based gravitational wave observatory, LISA. It demonstrated that the performance requirements for the interferometric measurement of two test masses in free fall can be met. An important part of the data analysis is to identify the limiting noise sources. [1] This measurement is performed with heterodyne interferometry. The performance of this optical metrology system (OMS) at high frequencies is limited by sensing noise. One such noise source is Relative Intensity Noise (RIN). RIN is a property of the laser, and the photodiode current generated by the interferometer signal contains frequency dependant RIN. From this electric signal the phasemeter calculates the phase change and laser power, and the coupling of RIN into the measurement signal depends on the noise frequency. RIN at DC, at the heterodyne frequency and at two times the heterodyne frequency couples into the phase. Another important noise at high frequencies is path length noise. To reduce the impact this noise is suppressed with a control loop. Path length noise not suppressed will couple directly into the length measurement. The subtraction techniques of both noise sources depend on the phase difference between the reference signal and the measurement signal, and thus on the test mass position. During normal operations we position the test mass at the interferometric zero, which is optimal for noise subtraction purposes. This paper will show results from an in-flight experiment where the test mass position was changed to make the position dependant noise visible.

  11. Développement et exploitation d'un simulateur électro-optique pour le futur détecteur spatial à ondes gravitationnelles eLISA

    OpenAIRE

    Gruning , Pierre

    2015-01-01

    Gravitational waves will offer a new window to the universe. Their detection by ground based detectors should arrive soon and the future space based interferometer eLISA will allow to do gravitational wave astronomy in order to get unique informations on their sources wether black holes, neutron stars, the Big Bang etc. The effect of a gravitational wave is an extremely weak variation of distance, it will require a very performant detector. That’s why eLISA should reach picometer precision wi...

  12. Actuation crosstalk in free-falling systems: Torsion pendulum results for the engineering model of the LISA pathfinder gravitational reference sensor

    Science.gov (United States)

    Bassan, M.; Cavalleri, A.; De Laurentis, M.; De Marchi, F.; De Rosa, R.; Di Fiore, L.; Dolesi, R.; Finetti, N.; Garufi, F.; Grado, A.; Hueller, M.; Marconi, L.; Milano, L.; Minenkov, Y.; Pucacco, G.; Stanga, R.; Vetrugno, D.; Visco, M.; Vitale, S.; Weber, W. J.

    2018-01-01

    In this paper we report on measurements on actuation crosstalk, relevant to the gravitational reference sensors for LISA Pathfinder and LISA. In these sensors, a Test Mass (TM) falls freely within a system of electrodes used for readout and control. These measurements were carried out on ground with a double torsion pendulum that allowed us to estimate both the torque injected into the sensor when a control force is applied and, conversely, the force leaking into the translational degree of freedom due to the applied torque.The values measured on our apparatus (the engineering model of the LISA Pathfinder sensor) agree to within 0.2% (over a maximum measured crosstalk of 1%) with predictions of a mathematical model when measuring force to torque crosstalk, while it is somewhat larger than expected (up to 3.5%) when measuring torque to force crosstalk. However, the values in the relevant range, i.e. when the TM is well centered ( ± 10 μm) in the sensor, remain smaller than 0.2%, satisfying the LISA Pathfinder requirements.

  13. Complicating Culture and Difference: Situating Asian American Youth Identities in Lisa Yee's "Millicent Min," "Girl Genius" and "Stanford Wong Flunks Big-Time"

    Science.gov (United States)

    Endo, Rachel

    2009-01-01

    This review situates how culture, difference, and identity are discursively constructed in "Millicent Min, Girl Genius" and "Stanford Wong Flunks Big-Time," two award-winning books written by critically acclaimed Asian American author Lisa Yee. Using contextual literacy approaches, the characters, cultural motifs, and physical settings in these…

  14. Founders, Finding, Being Found: Women's Wisdom in Teaching and Learning in Theology and Religion

    Science.gov (United States)

    Hess, Lisa M.; Brosmer, Mary Pierce; Moore, Mary Elizabeth Mullino

    2015-01-01

    This is an edited transcript of a conversation between two founding women on the delights and demands of teaching and learning within and beyond traditional institutional life, facilitated by Lisa M. Hess of the journal's Editorial Board. The conscious feminine practices of a women's writing school, Women Writing for (a) Change (Cincinnati, Ohio),…

  15. Learning

    Directory of Open Access Journals (Sweden)

    Mohsen Laabidi

    2014-01-01

    Full Text Available Nowadays learning technologies transformed educational systems with impressive progress of Information and Communication Technologies (ICT. Furthermore, when these technologies are available, affordable and accessible, they represent more than a transformation for people with disabilities. They represent real opportunities with access to an inclusive education and help to overcome the obstacles they met in classical educational systems. In this paper, we will cover basic concepts of e-accessibility, universal design and assistive technologies, with a special focus on accessible e-learning systems. Then, we will present recent research works conducted in our research Laboratory LaTICE toward the development of an accessible online learning environment for persons with disabilities from the design and specification step to the implementation. We will present, in particular, the accessible version “MoodleAcc+” of the well known e-learning platform Moodle as well as new elaborated generic models and a range of tools for authoring and evaluating accessible educational content.

  16. Avaliação do desempenho visual da lente intraocular difrativa multifocal - Zeiss AT Lisa 809 MTM

    Directory of Open Access Journals (Sweden)

    Lucas Monferrari Monteiro Vianna

    2014-04-01

    Full Text Available Objetivo: Avaliar a função visual dos pacientes com implante bilateral da LIO multifocal difrativa AT-Lisa 809 MTM por meio dos exames de acuidade visual com e sem correção óptica, curva de sensibilidade ao contraste, curva de desfoco e questionário de qualidade de função visual (VQF39. Métodos: Estudo clínico, prospectivo e de intervenção, que avaliou os resultados de 20 olhos de 10 pacientes, submetidos à facoemulsificação e implante de LIO, entre fevereiro e junho de 2012. Resultados: A ametropia residual média pós-operatória foi de 0,05 ± 0,42 (-0,75 a +1,25 D dioptrias esféricas e -0,30 ± 0,42 (0 a -1,25 D dioptrias cilíndricas. Na curva de desenfoque mono e binocular, a melhor acuidade visual média obtida com 0.00 D de desenfoque (AV de longe. O segundo pico foi obtido com desenfoque de -3,00 D, o que equivale à visão de perto a 33 cm. Entre esses picos, observamos uma perda de desempenho visual, com desenfoque de -2,00 D, que equivale a visão intermediária a 50 cm. A sensibilidade ao contraste foi similar aos relatados na literatura com este tipo de LIO, tanto com quanto sem ofuscamento, e é mostrada em gráficos. O questionário de função visual (VFQ-39 teve valor médio de 91,91 +- 6,82. Conclusão: A LIO multifocal difrativa AT-Lisa 809MTM (Carl Zeiss Meditec Company - Alemanha apresentou resultados condizentes com a literatura quando avaliada pelos exames de acuidade visual com e sem correção óptica, sensibilidade ao contraste, curva de desfoco e questionário de qualidade de função visual (VQF 39.

  17. On-ground testing of the role of adhesion in the LISA-Pathfinder test mass injection phase

    Science.gov (United States)

    Bortoluzzi, D.; Zanoni, C.; Conklin, J. W.

    2017-05-01

    Many space missions share the need to fly a free-falling body inside the spacecraft, as a reference for navigation and/or as a probe for the local gravitational field. When a mechanism is required to cage such an object during the launch phase, the need arises to release it to free-fall once the operational phase must be initiated in orbit. The criticality of this phase increases when the mechanical interfaces between the body and the mechanism are affected by adhesion and the actuation authority of the control system on the free-falling body is limited. Both conditions are realized in the LISA Pathfinder mission, which aims at injecting a gold-coated 2 kg cubic test mass into a nearly perfect geodesic trajectory to demonstrate the readiness of the developed technology for in-space gravity wave detection. The criticality of adhesion is widely recognized in space technology, because it can affect and jeopardize the functionality of mechanisms, when arising between moving parts. In the LISA Pathfinder case, metallic adhesion potentially plays a relevant role, mainly for two reasons. First, thanks to its properties (ductility, high surface energy) the gold coating on the proof mass easily produces cold weldings, especially in vacuum conditions. Second, the detachment of the proof mass from the releasing device occurs abruptly and a relevant influence of the separation velocity is expected on the strength of the welding. This can produce an excessive velocity of the proof mass at the retraction of the releasing device for the following capture and centring phase on behalf of the control system. A testing activity is performed to characterize the dynamic behaviour of the adhesive bonds between the proof mass and the releasing device, which can be used to predict their contribution on the residual velocity of the proof mass after in-flight release. The study of such a dynamic phenomenon sets some challenging requirements on the measurement technique, both on the

  18. Searching for galactic white-dwarf binaries in mock LISA data using an F-statistic template bank

    International Nuclear Information System (INIS)

    Whelan, John T; Prix, Reinhard; Khurana, Deepak

    2010-01-01

    We describe an F-statistic search for continuous gravitational waves from galactic white-dwarf binaries in simulated LISA data. Our search method employs a hierarchical template-grid-based exploration of the parameter space. In the first stage, candidate sources are identified in searches using different simulated laser signal combinations (known as TDI variables). Since each source generates a primary maximum near its true 'Doppler parameters' (intrinsic frequency and sky position) as well as numerous secondary maxima of the F-statistic in Doppler parameter space, a search for multiple sources needs to distinguish between true signals and secondary maxima associated with other 'louder' signals. Our method does this by applying a coincidence test to reject candidates which are not found at nearby parameter space positions in searches using each of the three TDI variables. For signals surviving the coincidence test, we perform a fully coherent search over a refined parameter grid to provide an accurate parameter estimation for the final candidates. Suitably tuned, the pipeline is able to extract 1989 true signals with only 5 false alarms. The use of the rigid adiabatic approximation allows recovery of signal parameters with errors comparable to statistical expectations, although there is still some systematic excess with respect to statistical errors expected from Gaussian noise. An experimental iterative pipeline with seven rounds of signal subtraction and reanalysis of the residuals allows us to increase the number of signals recovered to a total of 3419 with 29 false alarms.

  19. Measurement of the momentum transferred between contacting bodies during the LISA test-mass release phase—uncertainty estimation

    International Nuclear Information System (INIS)

    De Cecco, M; Bortoluzzi, D; Da Lio, M; Baglivo, L; Benedetti, M

    2009-01-01

    The requirements for the Laser Interferometer Space Antenna (LISA) test-mass (TM) release phase are analysed in view of the building up of a testing facility aimed at on-Earth qualification of the release mechanism. Accordingly, the release of the TM to free-fall must provide a linear momentum transferred to the TM not exceeding 10 −5 kg m s −1 . In order to test this requirement, a double pendulum system has been developed. The mock-ups of the TM and the release-dedicated plunger are brought into contact and then the latter is quickly retracted. During and after release, the TM motion is measured by a laser interferometer. The transferred momentum is estimated from the free oscillations following the plunger retraction by means of a Wiener–Kolmogorov optimal filter. This work is aimed at modelling the measurement chain, taking into account procedure, instruments, mechanisms and data elaboration in order to estimate the uncertainty associated with the transferred momentum measurement by means of Monte Carlo simulation

  20. Fundamental performance determining factors of the ultrahigh-precision space-borne optical metrology system for the LISA Pathfinder mission

    Science.gov (United States)

    Hechenblaikner, Gerald; Flatscher, Reinhold

    2013-05-01

    The LISA Pathfinder mission to space employs an optical metrology system (OMS) at its core to measure the distance and attitude between two freely floating test-masses to picometer and nanorad accuracy, respectively, within the measurement band of [1 mHz, 30 mHz]. The OMS is based upon an ultra-stable optical bench with 4 heterodyne interferometers from which interference signals are read-out and processed by a digital phase-meter. Laser frequency noise, power fluctuations and optical path-length variations are suppressed to uncritical levels by dedicated control loops so that the measurement performance approaches the sensor limit imposed by the phasemeter. The system design is such that low frequency common mode noise which affects the read-out phase of all four interferometers is generally well suppressed by subtraction of a reference phase from the other interferometer signals. However, high frequency noise directly affects measurement performance and its common mode rejection depends strongly on the relative signal phases. We discuss how the data from recent test campaigns point towards high frequency phase noise as a likely performance limiting factor which explains some important performance features.

  1. Searching for galactic white-dwarf binaries in mock LISA data using an F-statistic template bank

    Energy Technology Data Exchange (ETDEWEB)

    Whelan, John T [Center for Computational Relativity and Gravitation, School of Mathematical Sciences, Rochester Institute of Technology, 85 Lomb Memorial Drive, Rochester, NY 14623 (United States); Prix, Reinhard [Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut), D-30167 Hannover (Germany); Khurana, Deepak, E-mail: john.whelan@astro.rit.ed, E-mail: reinhard.prix@aei.mpg.d [Indian Institute of Technology, Kharagpur, West Bengal 721302 (India)

    2010-03-07

    We describe an F-statistic search for continuous gravitational waves from galactic white-dwarf binaries in simulated LISA data. Our search method employs a hierarchical template-grid-based exploration of the parameter space. In the first stage, candidate sources are identified in searches using different simulated laser signal combinations (known as TDI variables). Since each source generates a primary maximum near its true 'Doppler parameters' (intrinsic frequency and sky position) as well as numerous secondary maxima of the F-statistic in Doppler parameter space, a search for multiple sources needs to distinguish between true signals and secondary maxima associated with other 'louder' signals. Our method does this by applying a coincidence test to reject candidates which are not found at nearby parameter space positions in searches using each of the three TDI variables. For signals surviving the coincidence test, we perform a fully coherent search over a refined parameter grid to provide an accurate parameter estimation for the final candidates. Suitably tuned, the pipeline is able to extract 1989 true signals with only 5 false alarms. The use of the rigid adiabatic approximation allows recovery of signal parameters with errors comparable to statistical expectations, although there is still some systematic excess with respect to statistical errors expected from Gaussian noise. An experimental iterative pipeline with seven rounds of signal subtraction and reanalysis of the residuals allows us to increase the number of signals recovered to a total of 3419 with 29 false alarms.

  2. Design and construction of an optical test bed for LISA imaging systems and tilt-to-length coupling

    International Nuclear Information System (INIS)

    Chwalla, M; Fitzsimons, E; Danzmann, K; Fernández Barranco, G; Gerberding, O; Heinzel, G; Lieser, M; Schuster, S; Schwarze, T S; Tröbs, M; Zwetz, M; Killow, C J; Perreur-Lloyd, M; Robertson, D I; Ward, H

    2016-01-01

    The laser interferometer space antenna (LISA) is a future space-based interferometric gravitational-wave detector consisting of three spacecraft in a triangular configuration. The interferometric measurements of path length changes between satellites will be performed on optical benches in the satellites. Angular misalignments of the interfering beams couple into the length measurement and represent a significant noise source. Imaging systems will be used to reduce this tilt-to-length coupling. We designed and constructed an optical test bed to experimentally investigate tilt-to-length coupling. It consists of two separate structures, a minimal optical bench and a telescope simulator. The minimal optical bench comprises the science interferometer where the local laser is interfered with light from a remote spacecraft. In our experiment, a simulated version of this received beam is generated on the telescope simulator. The telescope simulator provides a tilting beam, a reference interferometer and an additional static beam as a phase reference. The tilting beam can either be a flat-top beam or a Gaussian beam. We avoid tilt-to-length coupling in the reference interferometer by using a small photo diode placed at an image of the beam rotation point. We show that the test bed is operational with an initial measurement of tilt-to-length coupling without imaging systems. Furthermore, we show the design of two different imaging systems whose performance will be investigated in future experiments. (paper)

  3. Diseño de un plan de marketing para el producto lisa college desarrollado por la microempresa browse Ecuador, ubicada en la ciudad de Quito.

    OpenAIRE

    Coello Duque, Giomar Evelyn

    2013-01-01

    The present work aims to make a marketing plan for the product developed by Lisa College microenterprise Browse Ecuador Cia. Ltd. and it will be a guide for other micros companies wishing to conduct similar research. First, we review general information about the company under study in order to identify problems, research objectives and delimitation of the research area. With this knowledge provides the theoretical and conceptual framework underpinning this research. The ...

  4. Science with the space-based interferometer eLISA. III: probing the expansion of the universe using gravitational wave standard sirens

    Energy Technology Data Exchange (ETDEWEB)

    Tamanini, Nicola; Caprini, Chiara [Institut de Physique Théorique, CEA-Saclay, CNRS UMR 3681, Université Paris-Saclay, F-91191 Gif-sur-Yvette (France); Barausse, Enrico [Sorbonne Universités, UPMC Université Paris 6, UMR 7095, Institut d' Astrophysique de Paris, 98 bis Bd Arago, 75014 Paris (France); Sesana, Alberto [School of Physics and Astronomy, The University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Klein, Antoine [Department of Physics and Astronomy, The University of Mississippi, University, MS 38677 (United States); Petiteau, Antoine, E-mail: nicola.tamanini@cea.fr, E-mail: chiara.caprini@cea.fr, E-mail: barausse@iap.fr, E-mail: asesana@star.sr.bham.ac.uk, E-mail: aklein@physics.montana.edu, E-mail: antoine.petiteau@apc.univ-paris7.fr [APC, Université Paris Diderot, Observatoire de Paris, Sorbonne Paris Cité, 10 rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13 (France)

    2016-04-01

    We investigate the capability of various configurations of the space interferometer eLISA to probe the late-time background expansion of the universe using gravitational wave standard sirens. We simulate catalogues of standard sirens composed by massive black hole binaries whose gravitational radiation is detectable by eLISA, and which are likely to produce an electromagnetic counterpart observable by future surveys. The main issue for the identification of a counterpart resides in the capability of obtaining an accurate enough sky localisation with eLISA. This seriously challenges the capability of four-link (2 arm) configurations to successfully constrain the cosmological parameters. Conversely, six-link (3 arm) configurations have the potential to provide a test of the expansion of the universe up to z ∼ 8 which is complementary to other cosmological probes based on electromagnetic observations only. In particular, in the most favourable scenarios, they can provide a significant constraint on H{sub 0} at the level of 0.5%. Furthermore, (Ω{sub M}, Ω{sub Λ}) can be constrained to a level competitive with present SNIa results. On the other hand, the lack of massive black hole binary standard sirens at low redshift allows to constrain dark energy only at the level of few percent.

  5. Nested-PCR and a new ELISA-based NovaLisa test kit for malaria diagnosis in an endemic area of Thailand.

    Science.gov (United States)

    Thongdee, Pimwan; Chaijaroenkul, Wanna; Kuesap, Jiraporn; Na-Bangchang, Kesara

    2014-08-01

    Microscopy is considered as the gold standard for malaria diagnosis although its wide application is limited by the requirement of highly experienced microscopists. PCR and serological tests provide efficient diagnostic performance and have been applied for malaria diagnosis and research. The aim of this study was to investigate the diagnostic performance of nested PCR and a recently developed an ELISA-based new rapid diagnosis test (RDT), NovaLisa test kit, for diagnosis of malaria infection, using microscopic method as the gold standard. The performance of nested-PCR as a malaria diagnostic tool is excellent with respect to its high accuracy, sensitivity, specificity, and ability to discriminate Plasmodium species. The sensitivity and specificity of nested-PCR compared with the microscopic method for detection of Plasmodium falciparum, Plasmodium vivax, and P. falciparum/P. vivax mixed infection were 71.4 vs 100%, 100 vs 98.7%, and 100 vs 95.0%, respectively. The sensitivity and specificity of the ELISA-based NovaLisa test kit compared with the microscopic method for detection of Plasmodium genus were 89.0 vs 91.6%, respectively. NovaLisa test kit provided comparable diagnostic performance. Its relatively low cost, simplicity, and rapidity enables large scale field application.

  6. LISA Pathfinder author list

    International Nuclear Information System (INIS)

    2017-01-01

    M Armano, 1 H Audley, 2 G Auger, 3 J Baird, 4 M Bassan, 5 P Binetruy, 3 M Born, 2 D Bortoluzzi, 6 N Brandt, 7 M Caleno, 8 A Cavalleri, 9 A Cesarini, 9 M Cruise, 10 K Danzmann, 2 M de Deus Silva, 1 R De Rosa, 11 L Di Fiore, 12 I Diepholz, 2 R Dolesi, 9 N Dunbar, 13 L Ferraioli, 14 V Ferroni, 9 E Fitzsimons, 15 R Flatscher, 7 M Freschi, 1 C García Marrirodriga, 8 R Gerndt, 7 L Gesa, 16 F Gibert, 9 D Giardini, 14 R Giusteri, 9 A Grado, 11 C Grimani, 17 J Grzymisch, 8 I Harrison, 18 G Heinzel, 2 M Hewitson, 2 D Hollington, 4 D Hoyland, 10 M Hueller, 9 H Inchauspé, 3 O Jennrich, 8 P Jetzer, 19 B Johlander, 8 N Karnesis, 2 B Kaune, 2 N Korsakova, 2 C Killow, 20 A Lobo, 16 , I Lloro, 16 L Liu, 9 J.P. López-Zaragoza, 16 R Maarschalkerweerd, 18 D Mance, 14 V Martín, 16 L Martin-Polo, 1 J Martino, 3 F Martin-Porqueras, 1 S Madden, 8 I Mateos, 16 P W McNamara, 8 J Mendes, 18 L Mendes, 1 M Nofrarias, 16 S Paczkowski, 2 M Perreur-Lloyd, 20 A Petiteau, 3 P Pivato, 9 E Plagnol, 3 P Prat, 3 U Ragnit, 8 J Ramos-Castro, 21 J Reiche, 2 D I Robertson, 20 H Rozemeijer, 8 F Rivas, 16 G Russano, 9 P Sarra, 22 A Schleicher, 7 D Shaul, 4 J Slutsky, 23 C F Sopuerta, 16 R Stanga, 24 T Sumner, 4 D Texier, 1 J I Thorpe, 23 C Trenkel, 13 M Troebs, 2 D Vetrugno, 9 S Vitale, 9 G Wanner, 2 H Ward, 20 P Wass, 4 D Wealthy, 13 W J Weber, 9 L Wissel, 2 A Wittchen, 2 A Zambotti, 6 C Zanoni, 6 T Ziegler, 7 and P Zweifel 14 1 European Space Astronomy Centre, European Space Agency, Villanueva de la Cañada, 28692 Madrid, Spain 2 Albert-Einstein-Institut, Max-Planck-Institut für Gravitationsphysik und Universität Hannover, Callinstrasse 38, 30167 Hannover, Germany 3 APC, Univ Paris Diderot, CNRS/IN2P3, CEA/lrfu, Obs de Paris, Sorbonne Paris Cité, France 4 High Energy Physics Group, Physics Department, Imperial College London, Blackett Laboratory, Prince Consort Road, London, SW7 2BW, UK 5 Dipartimento di Fisica, Università di Roma “Tor Vergata”, and INFN, sezione Roma Tor Vergata, I-00133 Roma, Italy 6 Department of Industrial Engineering, University of Trento, via Sommarive 9, 38123 Trento, and Trento Institute for Fundamental Physics and Application / INFN 7 Airbus Defence and Space, Claude-Dornier-Strasse, 88090 Immenstaad, Germany 8 European Space Technology Centre, European Space Agency, Keplerlaan 1, 2200 AG Noordwijk, The Netherlands 9 Dipartimento di Fisica, Università di Trento and Trento Institute for Fundamental Physics and Application / INFN, 38123 Povo, Trento, Italy 10 Department of Physics and Astronomy, University of Birmingham, Birmingham, UK 11 INAF Osservatorio Astronomico di Capodimonte, I-80131 Napoli, Italy and INFN sezione di Napoli, I-80126 Napoli, Italy 12 INFN - Sezione di Napoli, I-80126, Napoli, Italy 13 Airbus Defence and Space, Gunnels Wood Road, Stevenage, Hertfordshire, SG1 2AS, UK 14 Institut für Geophysik, ETH Zürich, Sonneggstrasse 5, CH-8092, Zürich, Switzerland 15 The UK Astronomy Technology Centre, Royal Observatory, Edinburgh, Blackford Hill, Edinburgh, EH9 3HJ, UK 16 Institut de Ciències de l’Espai (CSIC-IEEC), Campus UAB, Carrer de Can Magrans s/n, 08193 Cerdanyola del Vallès, Spain 17 DISPEA, Università di Urbino “Carlo Bo”, Via S. Chiara, 27 61029 Urbino/INFN, Italy 18 European Space Operations Centre, European Space Agency, 64293 Darmstadt, Germany 19 Physik Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland 20 SUPA, Institute for Gravitational Research, School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK 21 Department d’Enginyeria Electrònica, Universitat Politècnica de Catalunya, 08034 Barcelona, Spain 22 CGS S.p.A, Compagnia Generale per lo Spazio, Via Gallarate, 150 - 20151 Milano, Italy 23 Gravitational Astrophysics Lab, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 USA 24 Dipartimento di Fisica ed Astronomia, Università degli Studi di Firenze and INFN - Sezione di Firenze, I-50019 Firenze, Italy (paper)

  7. Measuring fN force variations in the presence of constant nN forces: a torsion pendulum ground test of the LISA Pathfinder free-fall mode

    Science.gov (United States)

    Russano, G.; Cavalleri, A.; Cesarini, A.; Dolesi, R.; Ferroni, V.; Gibert, F.; Giusteri, R.; Hueller, M.; Liu, L.; Pivato, P.; Tu, H. B.; Vetrugno, D.; Vitale, S.; Weber, W. J.

    2018-02-01

    LISA Pathfinder is a differential accelerometer with the main goal being to demonstrate the near perfect free-fall of reference test masses, as is needed for an orbiting gravitational wave observatory, with a target sensitivity of 30 fm s‑2 Hz-1/2 at 1 mHz. Any lasting background differential acceleration between the two test masses must be actively compensated, and noise associated with the applied actuation force can be a dominant source of noise. To remove this actuation, and the associated force noise, a ‘free-fall’ actuation control scheme has been designed; actuation is limited to brief impulses, with both test masses in free-fall in the time between the impulses, allowing measurement of the remaining acceleration noise sources. In this work, we present an on-ground torsion pendulum testing campaign of this technique and associated data analysis algorithms at a level nearing the sub-femto-g/\\sqrtHz performance required for LISA Pathfinder.

  8. A high sensitivity heterodyne interferometer as a possible optical readout for the LISA gravitational reference sensor and its application to technology verification

    Energy Technology Data Exchange (ETDEWEB)

    Gohlke, Martin; Weise, Dennis; Johann, Ulrich; Braxmaier, Claus [EADS Astrium, Claude-Dornier-Strasse, 88039 Friedrichshafen (Germany); Schuldt, Thilo; Peters, Achim, E-mail: martin.gohlke@astrium.eads.ne [Humboldt-Universitaet zu Berlin, Hausvogteiplatz 5-7, 10117 Berlin (Germany)

    2009-03-01

    The space-based gravitational wave detector LISA (Laser Interferometer Space Antenna) utilizes a high performance position sensor in order to measure the translation and tilt of the free flying proof mass with respect to the optical bench. Depending on the LISA optical bench design, this position sensor must have up to pm/sq rootHz sensitivity for the translation measurement and up to nrad/sq rootHz sensitivity for the tilt measurement. We developed a heterodyne interferometer, combined with differential wavefront sensing, for the tilt measurement. The interferometer design exhibits maximum symmetry where measurement and reference arm have the same frequency and polarization and the same optical path-lengths. The interferometer can be set up free of polarizing optical components preventing possible problems with thermal dependencies not suitable for the space environment. We developed a mechanically highly stable and compact setup which is located in a vacuum chamber. We measured initial noise levels below 10 pm/sq rootHz (longitudinal measurement) for frequencies above 10 mHz and below 20 nrad/sq rootHz (tilt measurement) for frequencies above 1 mHz. This setup can also be used for other applications, for example the measurement of the coefficient of thermal expansion (CTE) of structural materials, such as carbon fiber reinforced plastic (CFRP).

  9. Análise Bibliométrica da produção científica em gestão da informação na base de dados lisa / Bibliometrics analysis of scientific production in management information in the lisa database

    OpenAIRE

    Luiza da Silva Kleinubing

    2010-01-01

    Descreve e analisa as principais características bibliométricas das publicações relacionadas à área de gestão da informação da base de dados Lisa, uma das bases com maior visibilidade no campo da Biblioteconomia e Ciência da Informação. Foram analisados 138 artigos. A metodologia de pesquisa combina métodos bibliométricos e softwares, a característica da pesquisa é quantitativa, pois enumera e mede, e qualitativa, pois compreende e explica. Conclui-se sinalizando que os métodos bibliométricos...

  10. Validation of a short, qualitative food frequency questionnaire in French adults participating in the MONA LISA-NUT study 2005-2007.

    Science.gov (United States)

    Giovannelli, Jonathan; Dallongeville, Jean; Wagner, Aline; Bongard, Vanina; Laillet, Brigitte; Marecaux, Nadine; Ruidavets, Jean Bernard; Haas, Bernadette; Ferrieres, Jean; Arveiler, Dominique; Simon, Chantal; Dauchet, Luc

    2014-04-01

    Food frequency questionnaires (FFQs) are often used to evaluate individuals' food intakes in epidemiologic studies because of their simplicity and low cost. To assess the validity of a short (24 items), qualitative FFQ used in the MONA LISA-NUT study. Cross-sectional study of a representative sample in three French counties. The sample included 2,630 participants aged 35 to 65 years from the MONA LISA-NUT study. Food consumption was measured with the FFQ and via food records for 3 consecutive days. Plasma fatty acids were measured from a subset of participants. The FFQ items' validity was assessed by calculating crude and deattenuated Pearson correlation coefficients between frequencies reported by the FFQ and average weights reported by the food records. Furthermore, the validity of some items of the FFQ measuring the consumption of fatty foods was assessed by calculating Pearson correlation coefficients between frequencies of consumption of these foods and dosages of the corresponding plasma fatty acids: fish and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), olive oil and oleic acid, margarine and elaidic acid, and dairy products and pentadecanoic and heptadecanoic acids. The mean of the deattenuated Pearson correlation coefficients for all items was 0.46, with values ranging from 0.22 (fried food) to 0.77 (breakfast cereal). The correlation coefficient was ≤ 0.4 for one third of the 24 items. Moderate correlations were found between fish and EPA/DHA (EPA: r=0.43, 95% CI 0.33 to 0.51; DHA: r=0.39, 95% CI 0.30 to 0.47), but not for other food items. One third of the 24 items in the short, qualitative FFQ evaluated here were not sufficiently valid. However, for the food groups most commonly studied in the literature, this FFQ had the same degree of validity as other questionnaires designed to classify subjects according to their level of intake. Copyright © 2014 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

  11. Trap-efficiency investigation, Bernalillo Floodwater Retarding Reservoir No. 1 (Piedra Lisa Arroyo) near Bernalillo, New Mexico, water years 1956-1974

    Science.gov (United States)

    Funderburg, D.E.

    1977-01-01

    The U.S. Geological Survey, in cooperation with the U.S. Soil Conservation Service, began an investigation of sedimentation of Bernalillo Floodwater Retarding Reservoir No. 1 (Piedra Lisa Arroyo) near Bernalillo, New Mexico in 1956. This investigation was part of a nationwide investigation of the trap efficiency of detention reservoirs. Reservoirs No. 1 is normally a dry reservoir and runoff from the 10.6 sq km drainage area generally occurs from high-intensity summer thundershowers. The mesa area of the drainage basin was treated to prevent erosion and gullying and to retard rapid runoff of rainfall. The land treatment consisted of pits, terraces, seeding, and restricted grazing. The total outflow recorded for the period of record (July 19, 1956 to June 30, 1974) was 133 acre-feet, yielding 1 ,439 tons of sediment. Over 99 percent of the coarse sediments and a high percentage of the silts and clays were deposited in the reservoir before reaching the outflow pipe. The determined trap efficiency of Reservoir No. 1 was 96 percent for the period of record. (Woordard-USGS)

  12. Lisa maailmakirjanduse tõlkevaramule

    Index Scriptorium Estoniae

    2006-01-01

    Uued teosed sarjast "Maailmakirjanduse tõlkevaramu": Tirso de Molina "Sevilla pilkaja ja kivist külaline" ja Pedro Calderon de la Barca "Suur Maailmateater" (Tartu : Tartu Ülikooli Kirjastus, 2006)

  13. Learning How to Learn

    DEFF Research Database (Denmark)

    Lauridsen, Karen M.; Lauridsen, Ole

    Ole Lauridsen, Aarhus School of Business and Social Sciences, Aarhus University, Denmark Karen M. Lauridsen, Aarhus School of Business and Social Sciences, Aarhus University, Denmark Learning Styles in Higher Education – Learning How to Learn Applying learning styles (LS) in higher education...... by Constructivist learning theory and current basic knowledge of how the brain learns. The LS concept will thus be placed in a broader learning theoretical context as a strong learning and teaching tool. Participants will be offered the opportunity to have their own LS preferences established before...... teaching leads to positive results and enhanced student learning. However, learning styles should not only be considered a didactic matter for the teacher, but also a tool for the individual students to improve their learning capabilities – not least in contexts where information is not necessarily...

  14. Tumor misto de células musculares lisas e do estroma endometrial uterino: relato de caso Mixed endometrial stromal and smooth muscle tumor of the uterus: case report

    Directory of Open Access Journals (Sweden)

    Luiz Gustavo Oliveira Brito

    2012-12-01

    Full Text Available Os tumores mistos de células musculares lisas e do estroma endometrial uterino, caracterizados pela presença de componentes de ambas as linhagens, coexistindo em proporções quase equivalentes, são neoplasmas raros. Possuem potencial biológico incerto e se comportam de acordo com o componente estromal. A imuno-histoquímica é uma grande aliada no diagnóstico microscópico, pois a clínica e os exames de imagem não ajudam a diferenciá-los de outras doenças uterinas. Descrevemos o caso de uma paciente cuja hipótese diagnóstica era de leiomioma uterino e que, após cirurgia, foi diagnosticada pelo estudo anatomopatológico como tumor misto de células musculares lisas e do estroma endometrial uterino.Mixed tumors of uterine smooth muscle and endometrial stromal cells, which are characterized by the presence of components from both cell lineages with similar proportions, are rare neoplasms. Their biological potential is uncertain, and they behave according to the stromal component. Immunohistochemistry is an important ally in microscopic diagnosis, because symptoms and imaging exams do not help in the differentiation from other uterine diseases. We describe a case of a patient who had been previously diagnosed with uterine leiomyoma, and after surgery, the anatomopathological study revealed a mixed tumor of uterine smooth muscle and endometrial stromal cells.

  15. Learning to Learn.

    Science.gov (United States)

    Weiss, Helen; Weiss, Martin

    1988-01-01

    The article reviews theories of learning (e.g., stimulus-response, trial and error, operant conditioning, cognitive), considers the role of motivation, and summarizes nine research-supported rules of effective learning. Suggestions are applied to teaching learning strategies to learning-disabled students. (DB)

  16. Deep learning for media analysis in defense scenariosan evaluation of an open source framework for object detection in intelligence related image sets

    Science.gov (United States)

    2017-06-01

    Community scikit-learn [4] Feb 2010 University of Montreal LISA Lab Theano [5] Mar 2010 Berkley Vision and Learning Center Caffe [6] Oct 2013 Google...Institute at Carnegie Mellon University summarize these frustrations well: “It is disturbing, however, that many problems associated with the...2 Score Cat. 3 Score Mob . Home(-) mobile home 0.946 revolver 0.002 boathouse 0.001 Mob . Home(+) assault rifle 0.586 mobile home 0.159 rifle 0.158

  17. Learning Styles.

    Science.gov (United States)

    Missouri Univ., Columbia. Coll. of Education.

    Information is provided regarding major learning styles and other factors important to student learning. Several typically asked questions are presented regarding different learning styles (visual, auditory, tactile and kinesthetic, and multisensory learning), associated considerations, determining individuals' learning styles, and appropriate…

  18. Learning Networks, Networked Learning

    NARCIS (Netherlands)

    Sloep, Peter; Berlanga, Adriana

    2010-01-01

    Sloep, P. B., & Berlanga, A. J. (2011). Learning Networks, Networked Learning [Redes de Aprendizaje, Aprendizaje en Red]. Comunicar, XIX(37), 55-63. Retrieved from http://dx.doi.org/10.3916/C37-2011-02-05

  19. Thematic Categorization and Analysis of Peer Reviewed Articles in the LISA Database, 2004-2005. A Review of: Gonzalez-Alcaide, Gregorio, Lourdes Castello-Cogolles, Carolina Navarro-Molina, et al. “Library and Information Science Research Areas: Analysis of Journal Articles in LISA.” Journal of the American Society for Information Science and Technology 59.1 (2008: 150-4.

    Directory of Open Access Journals (Sweden)

    Carol Perryman

    2009-03-01

    Full Text Available Objective – To provide an updated categorization of Library and Information Science (LIS publications and to identify trends in LIS research.Design – Bibliometric study.Setting – The Library and Information Science Abstracts (LISA database via the CSA Illumina interface.Subjects – 11,273 item records published from 2004-2005 and indexed in LISA.Methods – First, a search was set up to retrieve all records from 2004-2005, limited to peer review items (called “arbitrated works” by the authors (150 and excluding book reviews. Second, thematic descriptor terms used for the records were identified. Frequency counts for descriptor term occurrence were compiled using Microsoft Access and Pajek software programs. From the results of this search, the top terms were analyzed using the Kamada-Kawai algorithm in order to eliminate descriptor term co-occurrence frequencies under 30. A cluster analysis was used to depict thematic foci for the remaining records, providing a co-word network that visually identified topic areas of most frequent publication. Conclusions were drawn from these findings, and recommendations for further research were provided.Main Results – The authors identified 18 “thematic research core fields” (152 clustered around three large categories, “World Wide Web”, “Education”, and “Libraries”, plus 12 additional peripheral categories, and provided a schematic of field interrelationships.Conclusion – Domains of greatest focus for research “continue to be of practical and applied nature,” (153 but include increased emphasis on the World Wide Web and communications technologies, as well as on user studies. A table of the most frequently occurring areas of research along with their top three descriptor terms is provided (Table1, 152 (e.g., “World Wide Web” as the top area of research, with “online information retrieval” (268 occurrences, “searching” (132 occurrences, and “web sites” (115

  20. Learning Problems

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Learning Problems KidsHealth / For Kids / Learning Problems What's in ... for how to make it better. What Are Learning Disabilities? Learning disabilities aren't contagious, but they ...

  1. Learning about Learning

    Science.gov (United States)

    Siegler, Robert S.

    2004-01-01

    The field of children's learning was thriving when the Merrill-Palmer Quarterly was launched; the field later went into eclipse and now is in the midst of a resurgence. This commentary examines reasons for these trends, and describes the emerging field of children's learning. In particular, the new field is seen as differing from the old in its…

  2. Learning to Learn Differently

    Science.gov (United States)

    Olsen, Trude Høgvold; Glad, Tone; Filstad, Cathrine

    2018-01-01

    Purpose: This paper aims to investigate whether the formal and informal learning patterns of community health-care nurses changed in the wake of a reform that altered their work by introducing new patient groups, and to explore whether conditions in the new workplaces facilitated or impeded shifts in learning patterns. Design/methodology/approach:…

  3. Desarrollo y caracterización de un nuevo esmalte antideslizante de textura lisa y de fácil limpieza para baldosas de gres porcelánico

    Directory of Open Access Journals (Sweden)

    E. Barrachina Albert

    2016-03-01

    Full Text Available Dada la problemática que presentan los esmaltes antideslizantes convencionales, los cuales poseen una rugosidad superficial que dificulta la limpieza de la superficie de la pieza, se ha diseñado un esmalte antideslizante de naturaleza vitrocerámica que es resistente a las manchas y presenta una textura lisa, de tacto suave. Para ello, se han utilizado nuevas fritas de naturaleza mate y materias primas de composiciones similares, suficientemente refractarias para ser adecuadas para esmaltar piezas de gres porcelánico. El esmalte vitrocerámico así obtenido se ha caracterizado a través de varias técnicas instrumentales (fluorescencia de rayos X [FRX], microscopia electrónica de barrido [MEB], difracción de rayos X [DRX], perfilometría mecánica y medidas de microdureza con el fin de comprobar la naturaleza de las fases cristalizadas, su morfología, la rugosidad superficial y la microdureza de la pieza acabada. Además, se ha valorado la calidad de la pieza esmaltada mediante las normativas de resistencia química, resistencia a las manchas y resistencia a la resbaladicidad. El esmalte obtenido ha desvitrificado en cristales de silicoaluminatos de calcio y bario, cumple la normativa de antideslizamiento y es resistente a las manchas, ya que presenta una rugosidad superficial similar a un esmalte no antideslizante.

  4. Sistema de reforço à punção de lajes lisas de concreto armado com polímeros reforçados com fibra de carbono (PRFC

    Directory of Open Access Journals (Sweden)

    G. S. Santos

    Full Text Available Este artigo apresenta um estudo analítico de uma recente técnica de reforço de lajes lisas de concreto armado contra o fenômeno da punção. Trata-se da utilização de mantas de Polímeros Reforçados com Fibra de Carbono (PRFC como armadura de cisalhamento. O sistema, denominado Stitch, foi idealizado por Sissakis (2002 [1] e consiste em se formar um laço completo entre dois furos subsequentes como pontos de costura . O objetivo deste artigo é avaliar a aplicação de adaptações das principais normas, nacional e internacionais, de dimensionamento à punção de lajes com pilar interno, sem a atuação de momentos fletores e associadas às limitações do ACI 440 2R:2008 [6], a qual trata do reforço de estruturas com PRFC. Os Resultados mostram que a NBR 6118:2007 [4] apresentou o menor grau de dispersão, com alguns resultados contra a segurança. O ACI 318:2011 possui uma tendência mais conservadora, e o EUROCODE 2:2004 [4] e Model Code (2010 [5] possuem resultados intermediários, com esse ligeiramente mais conservador que aquele.

  5. Distance Learning

    National Research Council Canada - National Science Library

    Braddock, Joseph

    1997-01-01

    A study reviewing the existing Army Distance Learning Plan (ADLP) and current Distance Learning practices, with a focus on the Army's training and educational challenges and the benefits of applying Distance Learning techniques...

  6. Blended learning

    DEFF Research Database (Denmark)

    Dau, Susanne

    2016-01-01

    Blended Learning has been implemented, evaluated and researched for the last decades within different educational areas and levels. Blended learning has been coupled with different epistemological understandings and learning theories, but the fundamental character and dimensions of learning...... in blended learning are still insufficient. Moreover, blended learning is a misleading concept described as learning, despite the fact that it fundamentally is an instructional and didactic approach (Oliver & Trigwell, 2005) addressing the learning environment (Inglis, Palipoana, Trenhom & Ward, 2011......) instead of the learning processes behind. Much of the existing research within the field seems to miss this perspective. The consequence is a lack of acknowledgement of the driven forces behind the context and the instructional design limiting the knowledge foundation of learning in blended learning. Thus...

  7. Learn, how to learn

    Science.gov (United States)

    Narayanan, M.

    2002-12-01

    Ernest L. Boyer, in his 1990 book, "Scholarship Reconsidered: Priorities of the Professorate" cites some ground breaking studies and offers a new paradigm that identifies the need to recognize the growing conversation about teaching, scholarship and research in the Universities. The use of `ACORN' model suggested by Hawkins and Winter to conquer and mastering change, may offer some helpful hints for the novice professor, whose primary objective might be to teach students to `learn how to learn'. Action : It is possible to effectively change things only when a teaching professor actually tries out a new idea. Communication : Changes are successful only when the new ideas effectively communicated and implemented. Ownership : Support for change is extremely important and is critical. Only strong commitment for accepting changes demonstrates genuine leadership. Reflection : Feedback helps towards thoughtful evaluation of the changes implemented. Only reflection can provide a tool for continuous improvement. Nurture : Implemented changes deliver results only when nurtured and promoted with necessary support systems, documentation and infrastructures. Inspired by the ACORN model, the author experimented on implementing certain principles of `Total Quality Management' in the classroom. The author believes that observing the following twenty principles would indeed help the student learners how to learn, on their own towards achieving the goal of `Lifelong Learning'. The author uses an acronym : QUOTES : Quality Underscored On Teaching Excellence Strategy, to describe his methods for improving classroom teacher-learner participation. 1. Break down all barriers. 2. Create consistency of purpose with a plan. 3. Adopt the new philosophy of quality. 4. Establish high Standards. 5. Establish Targets / Goals. 6. Reduce dependence on Lectures. 7. Employ Modern Methods. 8. Control the Process. 9. Organize to reach goals. 10. Prevention vs. Correction. 11. Periodic Improvements. 12

  8. Intentional Learning Vs Incidental Learning

    OpenAIRE

    Shahbaz Ahmed

    2017-01-01

    This study is conducted to demonstrate the knowledge of intentional learning and incidental learning. Hypothesis of this experiment is intentional learning is better than incidental learning, participants were demonstrated and were asked to learn the 10 non sense syllables in a specific sequence from the colored cards in the end they were asked to recall the background color of each card instead of non-sense syllables. Independent variables of the experiment are the colored cards containing n...

  9. Posthuman learning

    DEFF Research Database (Denmark)

    Hasse, Cathrine

    This book shall explore the concept of learning from the new perspective of the posthuman. The vast majority of cognitive, behavioral and part of the constructionist learning theories operate with an autonomous individual who learn in a world of separate objects. Technology is (if mentioned at all......) understood as separate from the individual learner and perceived as tools. Learning theory has in general not been acknowledging materiality in their theorizing about what learning is. A new posthuman learning theory is needed to keep up with the transformations of human learning resulting from new...... technological experiences. One definition of learning is that it is a relatively permanent change in behavior as the result of experience. During the first half of the twentieth century, two theoretical approaches dominated the domain of learning theory: the schools of thought commonly known as behaviorism...

  10. Learning e-Learning

    Directory of Open Access Journals (Sweden)

    Gabriel ZAMFIR

    2009-01-01

    Full Text Available What You Understand Is What Your Cognitive Integrates. Scientific research develops, as a native environment, knowledge. This environment consists of two interdependent divisions: theory and technology. First division occurs as a recursive research, while the second one becomes an application of the research activity. Over time, theories integrate methodologies and technology extends as infrastructure. The engine of this environment is learning, as the human activity of knowledge work. The threshold term of this model is the concepts map; it is based on Bloom’ taxonomy for the cognitive domain and highlights the notion of software scaffolding which is grounded in Vygotsky’s Social Development Theory with its major theme, Zone of Proximal Development. This article is designed as a conceptual paper, which analyzes specific structures of this type of educational research: the model reflects a foundation for a theory and finally, the theory evolves as groundwork for a system. The outcomes of this kind of approach are the examples, which are, theoretically, learning outcomes, and practically exist as educational objects, so-called e-learning.

  11. Blended Learning

    NARCIS (Netherlands)

    Van der Baaren, John

    2009-01-01

    Van der Baaren, J. (2009). Blended Learning. Presentation given at the Mini symposium 'Blended Learning the way to go?'. November, 5, 2009, The Hague, The Netherlands: Netherlands Defence Academy (NDLA).

  12. Interface learning

    DEFF Research Database (Denmark)

    Thorhauge, Sally

    2014-01-01

    "Interface learning - New goals for museum and upper secondary school collaboration" investigates and analyzes the learning that takes place when museums and upper secondary schools in Denmark work together in local partnerships to develop and carry out school-related, museum-based coursework...... for students. The research focuses on the learning that the students experience in the interface of the two learning environments: The formal learning environment of the upper secondary school and the informal learning environment of the museum. Focus is also on the learning that the teachers and museum...... professionals experience as a result of their collaboration. The dissertation demonstrates how a given partnership’s collaboration affects the students’ learning experiences when they are doing the coursework. The dissertation presents findings that museum-school partnerships can use in order to develop...

  13. Learning Disabilities

    Science.gov (United States)

    ... books. While his friends were meeting for pickup soccer games after school, he was back home in ... sometimes thought to contribute to learning disabilities. Poor nutrition early in life also may lead to learning ...

  14. Workplace learning

    DEFF Research Database (Denmark)

    Warring, Niels

    2005-01-01

    In November 2004 the Research Consortium on workplace learning under Learning Lab Denmark arranged the international conference “Workplace Learning – from the learner’s perspective”. The conference’s aim was to bring together researchers from different countries and institutions to explore...... and discuss recent developments in our understanding of workplace and work-related learning. The conference had nearly 100 participants with 59 papers presented, and among these five have been selected for presentation is this Special Issue....

  15. Children's Learning

    Science.gov (United States)

    Siegler, Robert S.

    2005-01-01

    A new field of children's learning is emerging. This new field differs from the old in recognizing that children's learning includes active as well as passive mechanisms and qualitative as well as quantitative changes. Children's learning involves substantial variability of representations and strategies within individual children as well as…

  16. Blended Learning

    Science.gov (United States)

    Imbriale, Ryan

    2013-01-01

    Teachers always have been and always will be the essential element in the classroom. They can create magic inside four walls, but they have never been able to create learning environments outside the classroom like they can today, thanks to blended learning. Blended learning allows students and teachers to break free of the isolation of the…

  17. Transformative Learning

    Science.gov (United States)

    Wang, Victor C. X.; Cranton, Patricia

    2011-01-01

    The theory of transformative learning has been explored by different theorists and scholars. However, few scholars have made an attempt to make a comparison between transformative learning and Confucianism or between transformative learning and andragogy. The authors of this article address these comparisons to develop new and different insights…

  18. Blended Learning

    OpenAIRE

    Bauerová, Andrea

    2013-01-01

    This thesis is focused on a new approach of education called blended learning. The history and developement of Blended Learning is described in the first part. Then the methods and tools of Blended Learning are evaluated and compared to the traditional methods of education. At the final part an efficient developement of the educational programs is emphasized.

  19. Just Learning

    Science.gov (United States)

    Larsen-Freeman, Diane

    2017-01-01

    In this "First Person Singular" essay, the author describes her education, teaching experience, and interest in understanding the learning of language. Anyone reading this essay will not be surprised to learn that the author's questions about language learning and optimal teaching methods were only met with further questions, and no…

  20. The LISA zero-signal solution

    International Nuclear Information System (INIS)

    Tinto, Massimo; Larson, Shane L

    2005-01-01

    We derive a time-delay interferometric (TDI) combination that has zero-response to a gravitational wave signal. This combination, which we have called the zero-signal solution, is a two-parameter family of linear combinations of the generators of the TDI space that has null gravitational wave response when its two parameters coincide with the values of the angles of the source location in the sky. Remarkably, the zero-signal solution does not rely on any assumptions about the gravitational waveform, and in fact it works for waveforms of any kind

  1. Data combinations accounting for LISA spacecraft motion

    International Nuclear Information System (INIS)

    Shaddock, Daniel A.; Tinto, Massimo; Estabrook, Frank B.; Armstrong, J.W.

    2003-01-01

    The laser interferometer space antenna is an array of three spacecraft in an approximately equilateral triangle configuration which will be used as a low-frequency gravitational wave detector. We present here new generalizations of the Michelson- and Sagnac-type time-delay interferometry data combinations. These combinations cancel laser phase noise in the presence of different up and down propagation delays in each arm of the array, and slowly varying systematic motion of the spacecraft. The gravitational wave sensitivities of these generalized combinations are the same as previously computed for the stationary cases, although the combinations are now more complicated. We introduce a diagrammatic representation to illustrate that these combinations are actually synthesized equal-arm interferometers

  2. Observing a Gravitational Wave Background With Lisa

    National Research Council Canada - National Science Library

    Tinto, M; Armstrong, J; Estabrook, F

    2000-01-01

    .... Comparison of the conventional Michelson interferometer observable with the fully-symmetric Sagnac data-type allows unambiguous discrimination between a gravitational wave background and instrumental noise. The method presented here can be used to detect a confusion-limited gravitational wave background.

  3. Learning Networks for Lifelong Learning

    OpenAIRE

    Sloep, Peter

    2009-01-01

    Presentation in a seminar organized by Christopher Hoadley at Penn State University, October 2004.Contains general introduction into the Learning Network Programme and a demonstration of the Netlogo Simulation of a Learning Network.

  4. Thermal and friction drop characteristic of heat exchangers with elliptical tubes and smooth fins//Caracterización térmica e hidráulica de intercambiadores de calor con tubos elípticos y aletas lisas

    Directory of Open Access Journals (Sweden)

    Rubén Borrajo-Pérez

    2012-09-01

    Full Text Available Pressure drop and heat transfer are the most important parameters in compact heat exchanger. There is a lack of information in the literature about heat exchanger with elliptical tube. The objective of this work was the experimental characterization of compact heat exchangers models using elliptical tube with eccentricity of 0,5 and smooth fins. The Reynolds numbers and the spacing were varied and always inside laminar regime. The experiments were conducted in an open wind tunnel using sublimation of naphthalene and the heat and mass transfer analogy. As results, the average and local Nusselt number and friction factor for 36 models were obtained. Correlations for Colburn and friction factors were presented. This correlations were obtained for 200lisas. El numero de Reynolds y los espaciamientos fueron variados, dentro del régimen laminar. Los experimentos fueron desarrollados en un túnel de viento de circuito abierto usando la sublimación de naftaleno y la analogía calor y masa. Los números de Nusselt medio, locales y el factor de fricción fueronobtenidos en forma de correlaciones de Factores de Fricción y Colburn. Las correlaciones, validas para 200

  5. Juvenile growth of white mullet Mugil curema (Teleostei: Mugilidae in a coastal lagoon southwest of the Gulf of California Crecimiento de juveniles de la lisa blanca Mugil curema (Teleostei: Mugilidae en una laguna costera del suroeste del golfo de California

    Directory of Open Access Journals (Sweden)

    Casimiro Quiñonez-Velázquez

    2011-01-01

    Full Text Available Otolith micro structure was used to determine the age and evaluate the growth of juvenile white mullet (Mugil curema during their residence in the coastal lagoon El Conchalito, B.C.S., Mexico, from May 1997 to May 1998. Juveniles were sampled monthly during the full and ebbing phases of the maximum high tide. The juveniles studied were between 16 and 42 mm standard length (SL and from 22 to 109 days old. The Gompertz growth model appropriately described the relationship between age and SL (r = 0.94. The average growth rate was 0.29 mm d-1 between 20 and 110 days of age, which was lower than the growth rate of the juveniles prior to entering the lagoon. This suggests that growth is faster along the coast than in the lagoon. The strategy of entering protected areas allows individuals to reach a size that maximizes escape from predators and, therefore, the probability of survival when reentering the coastal habitat.Utilizando la microestructura de los otolitos se determinó la edad y se evaluó el crecimiento de juveniles de lisa blanca Mugil curema durante su permanencia en la laguna costera El Conchalito, B.C.S., México, de mayo de 1997 a mayo de 1998. Los juveniles se recolectaron durante la fase estacionaria y de descenso de la maxima pleamar de cada mes. Durante el estudio, se analizaron juveniles de 16 a 42 mm de longitud estándar (LE con edad entre 22 y 109 días. El modelo de Gompertz describió adecuadamente la relación entre la edad y LE (r² = 0,94. La tasa promedio de crecimiento entre 20 y 110 días de edad fue de 0,29 mm día-1 , menor que la tasa de crecimiento de los juveniles antes de incorporarse a la laguna. Esto sugiere que el crecimiento es más rápido en la costa que en la laguna, y la estrategia de introducirse a zonas protegidas es para alcanzar una longitud que maximice el escape a la depredación y maximice la probabilidad de supervivencia cuando se reincorporen al ambiente costero.

  6. Learning organisations

    Directory of Open Access Journals (Sweden)

    Sabina Jelenc Krašovec

    2000-12-01

    Full Text Available A vast array of economical, social, political, cultural and other factors influences the transformed role of learning and education in the society, as well as the functioning of local community and its social and communication patterns. The influences which are manifested as global problems can only be successfully solved on the level of local community. Analogously with the society in general, there is a great need of transforming a local community into a learning, flexible and interconnected environment which takes into account different interests, wishes and needs regarding learning and being active. The fundamental answer to changes is the strategy of lifelong learning and education which requires reorganisation of all walks of life (work, free time, family, mass media, culture, sport, education and transforming of organisations into learning organisations. With learning society based on networks of knowledge individuals are turning into learning individuals, and organisations into learning organisations; people who learn take the responsibility of their progress, learning denotes partnership among learning people, teachers, parents, employers and local community, so that they work together to achieve better results.

  7. Learning Opportunities for Group Learning

    Science.gov (United States)

    Gil, Alfonso J.; Mataveli, Mara

    2017-01-01

    Purpose: This paper aims to analyse the impact of organizational learning culture and learning facilitators in group learning. Design/methodology/approach: This study was conducted using a survey method applied to a statistically representative sample of employees from Rioja wine companies in Spain. A model was tested using a structural equation…

  8. Mimetic Learning

    Directory of Open Access Journals (Sweden)

    Christoph Wulf

    2008-03-01

    Full Text Available Mimetic learning, learning by imitation, constitutes one of the most important forms of learning. Mimetic learning does not, however, just denote mere imitation or copying: Rather, it is a process by which the act of relating to other persons and worlds in a mimetic way leads to an en-hancement of one’s own world view, action, and behaviour. Mimetic learning is productive; it is related to the body, and it establishes a connection between the individual and the world as well as other persons; it creates practical knowledge, which is what makes it constitutive of social, artistic, and practical action. Mimetic learning is cultural learning, and as such it is crucial to teaching and education (Wulf, 2004; 2005.

  9. Deep learning

    CERN Document Server

    Goodfellow, Ian; Courville, Aaron

    2016-01-01

    Deep learning is a form of machine learning that enables computers to learn from experience and understand the world in terms of a hierarchy of concepts. Because the computer gathers knowledge from experience, there is no need for a human computer operator to formally specify all the knowledge that the computer needs. The hierarchy of concepts allows the computer to learn complicated concepts by building them out of simpler ones; a graph of these hierarchies would be many layers deep. This book introduces a broad range of topics in deep learning. The text offers mathematical and conceptual background, covering relevant concepts in linear algebra, probability theory and information theory, numerical computation, and machine learning. It describes deep learning techniques used by practitioners in industry, including deep feedforward networks, regularization, optimization algorithms, convolutional networks, sequence modeling, and practical methodology; and it surveys such applications as natural language proces...

  10. Learning Disabilities and ADHD

    Science.gov (United States)

    ... of illnesses and disabilities Learning disabilities and ADHD Learning disabilities and ADHD Learning disabilities affect how you ... ADHD. Learning disabilities Attention deficit hyperactivity disorder (ADHD) Learning disabilities top Having a learning disability does not ...

  11. Informal learning.

    Science.gov (United States)

    Callanan, Maureen; Cervantes, Christi; Loomis, Molly

    2011-11-01

    We consider research and theory relevant to the notion of informal learning. Beginning with historical and definitional issues, we argue that learning happens not just in schools or in school-aged children. Many theorists have contrasted informal learning with formal learning. Moving beyond this dichotomy, and away from a focus on where learning occurs, we discuss five dimensions of informal learning that are drawn from the literature: (1) non-didactive, (2) highly socially collaborative, (3) embedded in meaningful activity, (4) initiated by learner's interest or choice, and (5) removed from external assessment. We consider these dimensions in the context of four sample domains: learning a first language, learning about the mind and emotions within families and communities, learning about science in family conversations and museum settings, and workplace learning. Finally, we conclude by considering convergences and divergences across the different literatures and suggesting areas for future research. WIREs Cogni Sci 2011 2 646-655 DOI: 10.1002/wcs.143 For further resources related to this article, please visit the WIREs website. Copyright © 2011 John Wiley & Sons, Ltd.

  12. Machine Learning

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    Machine learning, which builds on ideas in computer science, statistics, and optimization, focuses on developing algorithms to identify patterns and regularities in data, and using these learned patterns to make predictions on new observations. Boosted by its industrial and commercial applications, the field of machine learning is quickly evolving and expanding. Recent advances have seen great success in the realms of computer vision, natural language processing, and broadly in data science. Many of these techniques have already been applied in particle physics, for instance for particle identification, detector monitoring, and the optimization of computer resources. Modern machine learning approaches, such as deep learning, are only just beginning to be applied to the analysis of High Energy Physics data to approach more and more complex problems. These classes will review the framework behind machine learning and discuss recent developments in the field.

  13. Doing learning

    DEFF Research Database (Denmark)

    Mathiasen, John Bang; Koch, Christian

    2014-01-01

    Purpose: To investigate how learning occurs in a systems development project, using a company developing wind turbine control systems in collaboration with customers as case. Design/methodology/approach: Dewey’s approach to learning is used, emphasising reciprocity between the individual...... learning processes and that the interchanges between materiality and systems developers block the learning processes due to a customer with imprecise demands and unclear system specifications. In the four cases discussed, learning does occur however. Research limitations/implications: A qualitative study...... focusing on individual systems developers gives limited insight into whether the learning processes found would occur in other systems development processes. Practical implications: Managers should ensure that constitutive means, such as specifications, are available, and that they are sufficiently...

  14. Metric learning

    CERN Document Server

    Bellet, Aurelien; Sebban, Marc

    2015-01-01

    Similarity between objects plays an important role in both human cognitive processes and artificial systems for recognition and categorization. How to appropriately measure such similarities for a given task is crucial to the performance of many machine learning, pattern recognition and data mining methods. This book is devoted to metric learning, a set of techniques to automatically learn similarity and distance functions from data that has attracted a lot of interest in machine learning and related fields in the past ten years. In this book, we provide a thorough review of the metric learnin

  15. Applying findings from a systematic review of workplace-based e-learning: implications for health information professionals.

    Science.gov (United States)

    Booth, Andrew; Carroll, Christopher; Papaioannou, Diana; Sutton, Anthea; Wong, Ruth

    2009-03-01

    To systematically review the UK published literature on e-learning in the health workplace and to apply the findings to one of the most prolific UK e-learning initiatives in the health sector--the National Library for Health Facilitated Online Learning Interactive Opportunity (FOLIO) Programme. Sensitive searches were conducted across ASSIA, Australian Education Index, British Education Index, cinahl, CSA Abstracts, Dissertation Abstracts, Emerald, ERIC, IBSS, Index to Theses, LISA, MEDLINE, PSYCINFO and Social Science Citation Index. Additional citations were identified from reference lists of included studies and of relevant reviews; citation tracking and contact with experts. Twenty-nine studies met the inclusion criteria and were coded and analysed using thematic analysis as described by Miles & Huberman (Qualitative Data Analysis: A Sourcebook of New Methods. Newbury Park, CA: Sage, 1984). Five broad themes were identified from the 29 included studies: (i) peer communication; (ii) flexibility; (iii) support; (iv) knowledge validation; and (v) course presentation and design. These broad themes were supported by a total of eleven sub-themes. Components from the FOLIO Programme were analysed and existing and proposed developments were mapped against each sub-theme. This provides a valuable framework for ongoing course development. Librarians involved in delivering and supporting e-learning can benefit from applying the findings from the systematic review to existing programmes, exemplified by the FOLIO Programme. The resultant framework can also be used in developing new e-learning programmes.

  16. Learning to learn in MOOCs

    DEFF Research Database (Denmark)

    Milligan, Sandra; Ringtved, Ulla Lunde

    This paper outlines one way of understanding what it is about learning in MOOCs that is so distinctive, and explores the implications for the design of MOOCs. It draws on an ongoing research study into the nature of learning in MOOCs at the University of Melbourne.......This paper outlines one way of understanding what it is about learning in MOOCs that is so distinctive, and explores the implications for the design of MOOCs. It draws on an ongoing research study into the nature of learning in MOOCs at the University of Melbourne....

  17. Learning Cultures

    DEFF Research Database (Denmark)

    Rasmussen, Lauge Baungaard

    1998-01-01

    the article present different concepts and modelsof learning. It discuss some strutural tendenciesof developing environmental management systemsand point out alternatives to increasing formalization of rules.......the article present different concepts and modelsof learning. It discuss some strutural tendenciesof developing environmental management systemsand point out alternatives to increasing formalization of rules....

  18. Blended learning

    DEFF Research Database (Denmark)

    Staugaard, Hans Jørgen

    2012-01-01

    Forsøg på at indkredse begrebet blended learning i forbindelse med forberedelsen af projekt FlexVid.......Forsøg på at indkredse begrebet blended learning i forbindelse med forberedelsen af projekt FlexVid....

  19. Reflective Learning

    African Journals Online (AJOL)

    dell

    The main intent of this study was to identify the impact of using learning log as a learning strategy on the academic performance of university students. Second year psychology students were included as subjects of this study. In the beginning of the study, the students were divided into two: experimental group (N = 60) and ...

  20. Perceptual learning.

    Science.gov (United States)

    Seitz, Aaron R

    2017-07-10

    Perceptual learning refers to how experience can change the way we perceive sights, sounds, smells, tastes, and touch. Examples abound: music training improves our ability to discern tones; experience with food and wines can refine our pallet (and unfortunately more quickly empty our wallet), and with years of training radiologists learn to save lives by discerning subtle details of images that escape the notice of untrained viewers. We often take perceptual learning for granted, but it has a profound impact on how we perceive the world. In this Primer, I will explain how perceptual learning is transformative in guiding our perceptual processes, how research into perceptual learning provides insight into fundamental mechanisms of learning and brain processes, and how knowledge of perceptual learning can be used to develop more effective training approaches for those requiring expert perceptual skills or those in need of perceptual rehabilitation (such as individuals with poor vision). I will make a case that perceptual learning is ubiquitous, scientifically interesting, and has substantial practical utility to us all. Copyright © 2017. Published by Elsevier Ltd.

  1. Pervasive Learning

    DEFF Research Database (Denmark)

    Helms, Niels Henrik; Larsen, Lasse Juel

    2009-01-01

    , it is not a specific place where you can access scarce information. Pervasive or ubiquitous communication opens up for taking the organizing and design of learning landscapes a step further. Furthermore it calls for theoretical developments, which can open up for a deeper understanding of the relationship between...... emerging contexts, design of contexts and learning....

  2. Flipped Learning

    DEFF Research Database (Denmark)

    Holmboe, Peter; Hachmann, Roland

    I FLIPPED LEARNING – FLIP MED VIDEO kan du læse om, hvordan du som underviser kommer godt i gang med at implementere video i undervisning, der har afsæt i tankerne omkring flipped learning. Bogen indeholder fire dele: I Del 1 fokuserer vi på det metarefleksive i at tænke video ind i undervisningen...

  3. Flipped Learning

    DEFF Research Database (Denmark)

    Hachmann, Roland; Holmboe, Peter

    arbejde med faglige problemstillinger gennem problembaserede og undersøgende didaktiske designs. Flipped Learning er dermed andet og mere end at distribuere digitale materialer til eleverne forud for undervisning. Flipped Learning er i lige så høj grad et syn på, hvordan undervisning med digitale medier...

  4. Situating learning

    DEFF Research Database (Denmark)

    Ribeiro, Gustavo; Georg, Susse; Finchman, Rob

    2004-01-01

    This paper looks at learning experiences in South Africa and Thailand by highlighting the role of context and culture in the learning process. The authors are based at Danish and South African higher education institutions and have contributed to DUCED's TFS programme in the positions of overall...

  5. Embodied Learning

    Science.gov (United States)

    Stolz, Steven A.

    2015-01-01

    This article argues that psychological discourse fails miserably to provide an account of learning that can explain how humans come to understand, particularly understanding that has been grasped meaningfully. Part of the problem with psychological approaches to learning is that they are disconnected from the integral role embodiment plays in how…

  6. Distance learning

    Directory of Open Access Journals (Sweden)

    Katarina Pucelj

    2006-12-01

    Full Text Available I would like to underline the role and importance of knowledge, which is acquired by individuals as a result of a learning process and experience. I have established that a form of learning, such as distance learning definitely contributes to a higher learning quality and leads to innovative, dynamic and knowledgebased society. Knowledge and skills enable individuals to cope with and manage changes, solve problems and also create new knowledge. Traditional learning practices face new circumstances, new and modern technologies appear, which enable quick and quality-oriented knowledge implementation. The centre of learning process at distance learning is to increase the quality of life of citizens, their competitiveness on the workforce market and ensure higher economic growth. Intellectual capital is the one, which represents the biggest capital of each society and knowledge is the key factor for succes of everybody, who are fully aware of this. Flexibility, openness and willingness of people to follow new IT solutions form suitable environment for developing and deciding to take up distance learning.

  7. Legitimate Learning.

    Science.gov (United States)

    Stevenson, John

    1997-01-01

    What is considered legitimate learning is culturally and contextually specific, depending on what values are involved. Different values are engaged depending on whether legitimate learning is considered transformation of the individual in relation to self, in relation to society, or in relation to the workplace. (SK)

  8. Machine Learning.

    Science.gov (United States)

    Kirrane, Diane E.

    1990-01-01

    As scientists seek to develop machines that can "learn," that is, solve problems by imitating the human brain, a gold mine of information on the processes of human learning is being discovered, expert systems are being improved, and human-machine interactions are being enhanced. (SK)

  9. Blended Learning as Transformational Institutional Learning

    Science.gov (United States)

    VanDerLinden, Kim

    2014-01-01

    This chapter reviews institutional approaches to blended learning and the ways in which institutions support faculty in the intentional redesign of courses to produce optimal learning. The chapter positions blended learning as a strategic opportunity to engage in organizational learning.

  10. "Learned Helplessness" or "Learned Incompetence"?

    Science.gov (United States)

    Sergent, Justine; Lambert, Wallace E.

    Studies in the past have shown that reinforcements independent of the subjects actions may induce a feeling of helplessness. Most experiments on learned helplessness have led researchers to believe that uncontrollability (non-contingency of feedback upon response) was the determining feature of learned helplessness, although in most studies…

  11. Teacher learning as workplace learning

    NARCIS (Netherlands)

    Imants, J.; Van Veen, K.

    2010-01-01

    Against the background of increasing attention in teacher professional development programs for situating teacher learning in the workplace, an overview is given of what is known in general and in educational workplace learning literature on the characteristics and conditions of the workplace.

  12. Learning, Learning Organisations and the Global Enterprise

    Science.gov (United States)

    Manikutty, Sankaran

    2009-01-01

    The steadily increasing degree of globalisation of enterprises implies development of many skills, among which the skills to learn are among the most important. Learning takes place at the individual level, but collective learning and organisational learning are also important. Learning styles of individuals are different and learning styles are…

  13. Can machine learning explain human learning?

    NARCIS (Netherlands)

    Vahdat, M.; Oneto, L.; Anguita, D.; Funk, M.; Rauterberg, G.W.M.

    2016-01-01

    Learning Analytics (LA) has a major interest in exploring and understanding the learning process of humans and, for this purpose, benefits from both Cognitive Science, which studies how humans learn, and Machine Learning, which studies how algorithms learn from data. Usually, Machine Learning is

  14. Evaluation of learning materials

    DEFF Research Database (Denmark)

    Bundsgaard, Jeppe; Hansen, Thomas Illum

    2011-01-01

    This paper presents a holistic framework for evaluating learning materials and designs for learning. A holistic evaluation comprises investigations of the potential learning potential, the actualized learning potential, and the actual learning. Each aspect is explained and exemplified through...

  15. Learning Spaces

    CERN Document Server

    Falmagne, Jean-Claude

    2011-01-01

    Learning spaces offer a rigorous mathematical foundation for practical systems of educational technology. Learning spaces generalize partially ordered sets and are special cases of knowledge spaces. The various structures are investigated from the standpoints of combinatorial properties and stochastic processes. Leaning spaces have become the essential structures to be used in assessing students' competence of various topics. A practical example is offered by ALEKS, a Web-based, artificially intelligent assessment and learning system in mathematics and other scholarly fields. At the heart of A

  16. Supportive Learning: Linear Learning and Collaborative Learning

    Science.gov (United States)

    Lee, Bih Ni; Abdullah, Sopiah; Kiu, Su Na

    2016-01-01

    This is a conceptual paper which is trying to look at the educational technology is not limited to high technology. However, electronic educational technology, also known as e-learning, has become an important part of today's society, which consists of a wide variety of approaches to digitization, components and methods of delivery. In the…

  17. Learning to learn: self-managed learning

    Directory of Open Access Journals (Sweden)

    Jesús Miranda Izquierdo

    2006-09-01

    Full Text Available Thi is article analyzes the potentialities and weaknesses that non directive Pedagogy presents, an example of the so called self managed pedagogy, whose postulates are good to analyze for the contributions that this position can make to the search of new ways of learning.

  18. Machine Learning

    Energy Technology Data Exchange (ETDEWEB)

    Chikkagoudar, Satish; Chatterjee, Samrat; Thomas, Dennis G.; Carroll, Thomas E.; Muller, George

    2017-04-21

    The absence of a robust and unified theory of cyber dynamics presents challenges and opportunities for using machine learning based data-driven approaches to further the understanding of the behavior of such complex systems. Analysts can also use machine learning approaches to gain operational insights. In order to be operationally beneficial, cybersecurity machine learning based models need to have the ability to: (1) represent a real-world system, (2) infer system properties, and (3) learn and adapt based on expert knowledge and observations. Probabilistic models and Probabilistic graphical models provide these necessary properties and are further explored in this chapter. Bayesian Networks and Hidden Markov Models are introduced as an example of a widely used data driven classification/modeling strategy.

  19. Learning Leadership

    DEFF Research Database (Denmark)

    Hertel, Frederik; Fast, Alf Michael

    2018-01-01

    Is leadership a result of inheritance or is it something one learns during formal learning in e.g. business schools? This is the essential question addressed in this article. The article is based on a case study involving a new leader in charge of a group of profession practitioners. The leader...... promotes his leadership as a profession comparable to the professions of practitioners. This promotion implies that leadership is something one can and probably must learn during formal learning. The practitioners on the other hand reject this comprehension of leadership and long for a fellow practitioner...... to lead the organization. While asked they are unable to describe how, where and when they think a practitioner develops leadership skills necessary for leading fellows. In the following we will start analysing the case in order to comprehend and discuss both the professional leaders and the practitioners...

  20. Group learning

    DEFF Research Database (Denmark)

    Pimentel, Ricardo; Noguira, Eloy Eros da Silva; Elkjær, Bente

    The article presents a study that aims at the apprehension of the group learning in a top management team composed by teachers in a Brazilian Waldorf school whose management is collective. After deciding to extend the school, they had problems recruiting teachers who were already trained based...... on the Steiner´s ideas, which created practical problems for conducting management activities. The research seeks to understand how that group of teachers collectively manage the school, facing the lack of resources, a significant heterogeneity in the relationships, and the conflicts and contradictions......, and they are interrelated to the group learning as the construction, maintenance and reconstruction of the intelligibility of practices. From this perspective, it can be said that learning is a practice and not an exceptional phenomenon. Building, maintaining and rebuilding the intelligibility is the group learning...

  1. Learning Disabilities

    Science.gov (United States)

    ... NICHD) See all related organizations Publications Problemas de aprendizaje Order NINDS Publications Patient Organizations CHADD - Children and ... NICHD) See all related organizations Publications Problemas de aprendizaje Order NINDS Publications Definition Learning disabilities are disorders ...

  2. Reflective Learning

    African Journals Online (AJOL)

    dell

    The experimental group students used learning log on a weekly basis while the control group did not. ... The term “memory” in psychology usually denotes an interest in the retention ... activities that contribute to information being remembered.

  3. Interorganizational learning systems

    DEFF Research Database (Denmark)

    Hjalager, Anne-Mette

    1999-01-01

    The occurrence of organizational and interorganizational learning processes is not only the result of management endeavors. Industry structures and market related issues have substantial spill-over effects. The article reviews literature, and it establishes a learning model in which elements from...... organizational environments are included into a systematic conceptual framework. The model allows four types of learning to be identified: P-learning (professional/craft systems learning), T-learning (technology embedded learning), D-learning (dualistic learning systems, where part of the labor force is exclude...... from learning), and S-learning (learning in social networks or clans). The situation related to service industries illustrates the typology....

  4. Lifelong Learning

    DEFF Research Database (Denmark)

    Krogh, Lone; Jensen, Annie Aarup

    2010-01-01

    Master education for adults has become a strategy for Lifelong Learning among many well-educated people in Denmark. This type of master education is part of the ‘parallel education system' in Denmark. As one of the first Danish universities who offered this type of Master education, Aalborg...... the intended as well as the unintended effects (personal and professional) of the master education. The data have been gathered among graduates from a specific master education, Master in Learning Processes, and the paper will draw on results from a quantitative survey based on a questionnaire answered by 120...

  5. Learning SPARQL

    CERN Document Server

    DuCharme, Bob

    2011-01-01

    Get hands-on experience with SPARQL, the RDF query language that's become a key component of the semantic web. With this concise book, you will learn how to use the latest version of this W3C standard to retrieve and manipulate the increasing amount of public and private data available via SPARQL endpoints. Several open source and commercial tools already support SPARQL, and this introduction gets you started right away. Begin with how to write and run simple SPARQL 1.1 queries, then dive into the language's powerful features and capabilities for manipulating the data you retrieve. Learn wha

  6. Deep Learning in Open Source Learning Streams

    DEFF Research Database (Denmark)

    Kjærgaard, Thomas

    2016-01-01

    This chapter presents research on deep learning in a digital learning environment and raises the question if digital instructional designs can catalyze deeper learning than traditional classroom teaching. As a theoretical point of departure the notion of ‘situated learning’ is utilized...... and contrasted to the notion of functionalistic learning in a digital context. The mechanism that enables deep learning in this context is ‘The Open Source Learning Stream’. ‘The Open Source Learning Stream’ is the notion of sharing ‘learning instances’ in a digital space (discussion board, Facebook group......, unistructural, multistructural or relational learning. The research concludes that ‘The Open Source Learning Stream’ can catalyze deep learning and that there are four types of ‘Open Source Learning streams’; individual/ asynchronous, individual/synchronous, shared/asynchronous and shared...

  7. Mastering machine learning with scikit-learn

    CERN Document Server

    Hackeling, Gavin

    2014-01-01

    If you are a software developer who wants to learn how machine learning models work and how to apply them effectively, this book is for you. Familiarity with machine learning fundamentals and Python will be helpful, but is not essential.

  8. Barriers and solutions to online learning in medical education - an integrative review.

    Science.gov (United States)

    O'Doherty, Diane; Dromey, Marie; Lougheed, Justan; Hannigan, Ailish; Last, Jason; McGrath, Deirdre

    2018-06-07

    The aim of this study is to review the literature on known barriers and solutions that face educators when developing and implementing online learning programs for medical students and postgraduate trainees. An integrative review was conducted over a three-month period by an inter-institutional research team. The search included ScienceDirect, Scopus, BioMedical, PubMed, Medline (EBSCO & Ovid), ERIC, LISA, EBSCO, Google Scholar, ProQuest A&I, ProQuest UK & Ireland, UL Institutional Repository (IR), UCDIR and the All Aboard Report. Search terms included online learning, medical educators, development, barriers, solutions and digital literacy. The search was carried out by two reviewers. Titles and abstracts were screened independently and reviewed with inclusion/exclusion criteria. A consensus was drawn on which articles were included. Data appraisal was performed using the Critical Appraisal Skills Programme (CASP) Qualitative Research Checklist and NHMRC Appraisal Evidence Matrix. Data extraction was completed using the Cochrane Data Extraction Form and a modified extraction tool. Of the 3101 abstracts identified from the search, ten full-text papers met the inclusion criteria. Data extraction was completed on seven papers of high methodological quality and on three lower quality papers. Findings suggest that the key barriers which affect the development and implementation of online learning in medical education include time constraints, poor technical skills, inadequate infrastructure, absence of institutional strategies and support and negative attitudes of all involved. Solutions to these include improved educator skills, incentives and reward for the time involved with development and delivery of online content, improved institutional strategies and support and positive attitude amongst all those involved in the development and delivery of online content. This review has identified barriers and solutions amongst medical educators to the implementation of

  9. Transforming learning?

    Science.gov (United States)

    1999-09-01

    A new Learning and Skills Council for post-16 learning is the latest proposal from the UK Government in its attempt to ensure a highly skilled workforce for the next century. Other aims will be to reduce the variability in standards of the existing post-16 system, coordination and coherence between further education and training, and a reduction in the duplication and layers in contracting and funding. The proposals include: a national Learning and Skills Council, with 40-50 local Learning and Skills Councils to develop local plans; a strengthened strategic role for business in education and training, influencing a budget of #5bn a radical new youth programme entitled `Connexions', with dedicated personal advisors for young people; greater cooperation between sixth forms and colleges; and the establishment of an independent inspectorate covering all work-related learning and training, to include a new role for Ofsted in inspecting the provision for 16-19 year-olds in schools and colleges. It is hoped that this programme will build on the successes of the previous systems and that savings of at least #50m can be achieved through streamlining and the reduction in bureaucracy. The intentions are set out in a White Paper, Learning to Succeed, which is available from the Stationery Office and bookshops, as well as on the website www.dfee.gov.uk/post16. Published in addition to the White Paper was `School Sixth form funding: a consultation paper' (available from DfEE publications, Prolog, PO Box 5050, Sherwood Park, Annesley, Nottingham NG15 0DJ) and `Transition plan for the post-16 education and training and for local delivery of support for small firms' (available from Trevor Tucknutt, TECSOP Division, Level 3, Department for Education and Employment, Moorfoot, Sheffield S1 4PQ). The deadline for comments on both the sixth form consultation document and the White Paper is 15 October 1999. Almost simultaneously with the announcement of the above proposals came the

  10. Deepening Learning through Learning-by-Inventing

    OpenAIRE

    Apiola, Mikko; Tedre, Matti

    2013-01-01

    It has been shown that deep approaches to learning, intrinsic motivation, and self-regulated learning have strong positive effects on learning. How those pedagogical theories can be integrated in computing curricula is, however, still lacking empirically grounded analyses. This study integrated, in a robotics-based programming class, a method of learning-by-inventing, and studied its qualitative effects on students’ learning through 144 interviews. Five findings were related with learning the...

  11. Learning and Behavior

    Science.gov (United States)

    ... List About PPMD Events News Login By Area Learning & Behavior Attention, Listening & Learning Autism Spectrum Disorder (ASD) ... Care Guidelines ❯ By Area ❯ Learning & Behavior Share Print Learning & Behavior Facts to Remember People with Duchenne may ...

  12. Learning via Query Synthesis

    KAUST Repository

    Alabdulmohsin, Ibrahim

    2017-01-01

    Active learning is a subfield of machine learning that has been successfully used in many applications. One of the main branches of active learning is query synthe- sis, where the learning agent constructs artificial queries from scratch in order

  13. Managing Learning for Performance.

    Science.gov (United States)

    Kuchinke, K. Peter

    1995-01-01

    Presents findings of organizational learning literature that could substantiate claims of learning organization proponents. Examines four learning processes and their contribution to performance-based learning management: knowledge acquisition, information distribution, information interpretation, and organizational memory. (SK)

  14. Learning Object Repositories

    Science.gov (United States)

    Lehman, Rosemary

    2007-01-01

    This chapter looks at the development and nature of learning objects, meta-tagging standards and taxonomies, learning object repositories, learning object repository characteristics, and types of learning object repositories, with type examples. (Contains 1 table.)

  15. Blocking in Category Learning

    OpenAIRE

    Bott, Lewis; Hoffman, Aaron B.; Murphy, Gregory L.

    2007-01-01

    Many theories of category learning assume that learning is driven by a need to minimize classification error. When there is no classification error, therefore, learning of individual features should be negligible. We tested this hypothesis by conducting three category learning experiments adapted from an associative learning blocking paradigm. Contrary to an error-driven account of learning, participants learned a wide range of information when they learned about categories, and blocking effe...

  16. Learned Helplessness

    Science.gov (United States)

    Hooker, Carol E.

    1976-01-01

    Learned helplessness--the belief that a person's actions have no influence on the outcome of an event--is similar in many respects to the crisis state and depression. The author shows how this impaired social and psychological functioning occurs and identifies techniques that the social worker can use to prevent it. (Author)

  17. Learning Disabilities.

    Science.gov (United States)

    Neuwirth, Sharyn

    This booklet uses hypothetical case examples to illustrate the definition, causal theories, and specific types of learning disabilities (LD). The cognitive and language performance of students with LD is compared to standard developmental milestones, and common approaches to the identification and education of children with LD are outlined.…

  18. Learning Together

    Science.gov (United States)

    Kaufman, Sherry

    2014-01-01

    In spring 2012, Sherry Kaufman, a consultant at Francis W. Parker School in Chicago, was asked to support kindergarten teachers in deepening their practice of constructivism and exploring the Reggio Emilia approach to early childhood education. Central to such an approach is the belief that all learning is socially constructed through interaction…

  19. Learning Mongoid

    CERN Document Server

    Rege, Gautam

    2013-01-01

    A step-by-step tutorial with focused examples that will help you build scalable, high performance Rails web applications with Mongoid.If you are an application developer who wants to learn how to use Mongoid in a Rails application, this book will be great for you. You are expected to be familiar with MongoDB and Ruby.

  20. Learning Lichens

    Science.gov (United States)

    Thorne, Sarah

    2017-01-01

    The lichen is an ideal subject for student study because it is omnipresent in school yards, easily collected and observed year-round, a pioneer of evolution on land, and a bioindicator of air pollution. After doing fieldwork on this unusual composite organism as an apprentice with a team of lichenologists, Sarah Thorne developed Learning Lichens.…

  1. Learning Ionic

    CERN Document Server

    Ravulavaru, Arvind

    2015-01-01

    This book is intended for those who want to learn how to build hybrid mobile applications using Ionic. It is also ideal for people who want to explore theming for Ionic apps. Prior knowledge of AngularJS is essential to complete this book successfully.

  2. Supervised Learning

    Science.gov (United States)

    Rokach, Lior; Maimon, Oded

    This chapter summarizes the fundamental aspects of supervised methods. The chapter provides an overview of concepts from various interrelated fields used in subsequent chapters. It presents basic definitions and arguments from the supervised machine learning literature and considers various issues, such as performance evaluation techniques and challenges for data mining tasks.

  3. Learning Analytics

    Directory of Open Access Journals (Sweden)

    Erik Duval

    2012-06-01

    Full Text Available This paper provides a brief introduction to the domain of ‘learning analytics’. We first explain the background and idea behind the concept. Then we give a brief overview of current research issues. We briefly list some more controversial issues before concluding.

  4. Learning Ansible

    CERN Document Server

    Mohaan, Madhurranjan

    2014-01-01

    If you want to learn how to use Ansible to automate an infrastructure, either from scratch or to augment your current tooling with Ansible, then this is the book for you. It has plenty of practical examples to help you get to grips with Ansible.

  5. Learning Physics

    International Nuclear Information System (INIS)

    Cohen, E.

    2005-01-01

    Full Text:The issue of Teaching physics vs Learning physics in our institutions of higher learning will be discussed. Physics is taught mainly by frontal lectures an old (and proven) method. The great advancements of the Information Age are introduced by exposing the students to vast amounts of computerized information and directing them to numerical problem solving by interacting with the computer. These modern methods have several drawbacks: 1. Students get the impression of easy material acquisition while in fact it becomes superficial. 2. There is little integration of topics that are taught in different courses. 3. Insufficient interest is built among undergraduate students to pursue studies that involve deeper thinking and independent research (namely, studies towards a doctoral degree). Learning physics is a formative process in the education of physicists, natural scientists and engineers. It must be based on discussions and exchange of ideas among the students, since understanding the studied material means being able to explain it to a colleague. Some universities in the US initiated programs of learning physics by creating an environment in which small groups of students are engaged in discussing material, jointly solving problems and jointly conducting simulated experiments. This is done under the supervision of a mentor. Suggestions for implementing this method in Israel will be discussed

  6. Influences of Formal Learning, Personal Learning Orientation, and Supportive Learning Environment on Informal Learning

    Science.gov (United States)

    Choi, Woojae; Jacobs, Ronald L.

    2011-01-01

    While workplace learning includes formal and informal learning, the relationship between the two has been overlooked, because they have been viewed as separate entities. This study investigated the effects of formal learning, personal learning orientation, and supportive learning environment on informal learning among 203 middle managers in Korean…

  7. From learning objects to learning activities

    DEFF Research Database (Denmark)

    Dalsgaard, Christian

    2005-01-01

    This paper discusses and questions the current metadata standards for learning objects from a pedagogical point of view. From a social constructivist approach, the paper discusses how learning objects can support problem based, self-governed learning activities. In order to support this approach......, it is argued that it is necessary to focus on learning activities rather than on learning objects. Further, it is argued that descriptions of learning objectives and learning activities should be separated from learning objects. The paper presents a new conception of learning objects which supports problem...... based, self-governed activities. Further, a new way of thinking pedagogy into learning objects is introduced. It is argued that a lack of pedagogical thinking in learning objects is not solved through pedagogical metadata. Instead, the paper suggests the concept of references as an alternative...

  8. How we learn

    DEFF Research Database (Denmark)

    Illeris, Knud

    How We Learn, deals with the fundamental issues of the processes of learning, critically assessing different types of learning and obstacles to learning. It also considers a broad range of other important questions in relation to learning such as: modern research into learning and brain functions......, self-perception, motivation and competence development, teaching, intelligence and learning style, learning in relation to gender and life age. The book provides a comprehensive introduction to both traditional learning theory and the newest international research into learning processes, while...... at the same time being an innovative contribution to a new and more holistic understanding of learning including discussion on school-based learning, net-based learning, workplace learning and educational politics. How We Learn examines all the key factors that help to create a holistic understanding of what...

  9. Using Learning Games to Meet Learning Objectives

    DEFF Research Database (Denmark)

    Henriksen, Thomas Duus

    2013-01-01

    This paper addresses the question on how learning games can be used to meet with the different levels in Bloom’s and the SOLO taxonomy, which are commonly used for evaluating the learning outcome of educational activities. The paper discusses the quality of game-based learning outcomes based on a...... on a case study of the learning game 6Styles....

  10. Still to Learn from Vicarious Learning

    Science.gov (United States)

    Mayes, J. T.

    2015-01-01

    The term "vicarious learning" was introduced in the 1960s by Bandura, who demonstrated how learning can occur through observing the behaviour of others. Such social learning is effective without the need for the observer to experience feedback directly. More than twenty years later a series of studies on vicarious learning was undertaken…

  11. Learning Effectiveness of a Strategic Learning Course

    Science.gov (United States)

    Burchard, Melinda S.; Swerdzewski, Peter

    2009-01-01

    The effectiveness of a postsecondary strategic learning course for improving metacognitive awareness and regulation was evaluated through systematic program assessment. The course emphasized students' awareness of personal learning through the study of learning theory and through practical application of specific learning strategies. Students…

  12. Social Media and Seamless Learning: Lessons Learned

    Science.gov (United States)

    Panke, Stefanie; Kohls, Christian; Gaiser, Birgit

    2017-01-01

    The paper discusses best practice approaches and metrics for evaluation that support seamless learning with social media. We draw upon the theoretical frameworks of social learning theory, transfer learning (bricolage), and educational design patterns to elaborate upon different ideas for ways in which social media can support seamless learning.…

  13. Deep Learning

    DEFF Research Database (Denmark)

    Jensen, Morten Bornø; Bahnsen, Chris Holmberg; Nasrollahi, Kamal

    2018-01-01

    I løbet af de sidste 10 år er kunstige neurale netværk gået fra at være en støvet, udstødt tekno-logi til at spille en hovedrolle i udviklingen af kunstig intelligens. Dette fænomen kaldes deep learning og er inspireret af hjernens opbygning.......I løbet af de sidste 10 år er kunstige neurale netværk gået fra at være en støvet, udstødt tekno-logi til at spille en hovedrolle i udviklingen af kunstig intelligens. Dette fænomen kaldes deep learning og er inspireret af hjernens opbygning....

  14. Learning Java

    CERN Document Server

    Niemeyer, Patrick

    2005-01-01

    Version 5.0 of the Java 2 Standard Edition SDK is the most important upgrade since Java first appeared a decade ago. With Java 5.0, you'll not only find substantial changes in the platform, but to the language itself-something that developers of Java took five years to complete. The main goal of Java 5.0 is to make it easier for you to develop safe, powerful code, but none of these improvements makes Java any easier to learn, even if you've programmed with Java for years. And that means our bestselling hands-on tutorial takes on even greater significance. Learning Java is the most widely sou

  15. Learning Raspbian

    CERN Document Server

    Harrington, William

    2015-01-01

    This book is intended for developers who have worked with the Raspberry Pi and who want to learn how to make the most of the Raspbian operating system and their Raspberry Pi. Whether you are a beginner to the Raspberry Pi or a seasoned expert, this book will make you familiar with the Raspbian operating system and teach you how to get your Raspberry Pi up and running.

  16. Guided discovery learning in geometry learning

    Science.gov (United States)

    Khasanah, V. N.; Usodo, B.; Subanti, S.

    2018-03-01

    Geometry is a part of the mathematics that must be learned in school. The purpose of this research was to determine the effect of Guided Discovery Learning (GDL) toward geometry learning achievement. This research had conducted at junior high school in Sukoharjo on academic years 2016/2017. Data collection was done based on student’s work test and documentation. Hypothesis testing used two ways analysis of variance (ANOVA) with unequal cells. The results of this research that GDL gave positive effect towards mathematics learning achievement. GDL gave better mathematics learning achievement than direct learning. There was no difference of mathematics learning achievement between male and female. There was no an interaction between sex differences and learning models toward student’s mathematics learning achievement. GDL can be used to improve students’ mathematics learning achievement in geometry.

  17. Learning to Learn Together with CSCL Tools

    Science.gov (United States)

    Schwarz, Baruch B.; de Groot, Reuma; Mavrikis, Manolis; Dragon, Toby

    2015-01-01

    In this paper, we identify "Learning to Learn Together" (L2L2) as a new and important educational goal. Our view of L2L2 is a substantial extension of "Learning to Learn" (L2L): L2L2 consists of learning to collaborate to successfully face L2L challenges. It is inseparable from L2L, as it emerges when individuals face problems…

  18. Technology, Learning, and Individual Differences

    Science.gov (United States)

    Bear, Anne A. Ghost

    2012-01-01

    The learning needs for adults that result from the constant increase in technology are rooted in the adult learning concepts of (a) andragogy, (b) self-directed learning, (c) learning-how-to-learn, (d) real-life learning, and (e) learning strategies. This study described the learning strategies that adults use in learning to engage in an online…

  19. Human Machine Learning Symbiosis

    Science.gov (United States)

    Walsh, Kenneth R.; Hoque, Md Tamjidul; Williams, Kim H.

    2017-01-01

    Human Machine Learning Symbiosis is a cooperative system where both the human learner and the machine learner learn from each other to create an effective and efficient learning environment adapted to the needs of the human learner. Such a system can be used in online learning modules so that the modules adapt to each learner's learning state both…

  20. Machine-Learning Research

    OpenAIRE

    Dietterich, Thomas G.

    1997-01-01

    Machine-learning research has been making great progress in many directions. This article summarizes four of these directions and discusses some current open problems. The four directions are (1) the improvement of classification accuracy by learning ensembles of classifiers, (2) methods for scaling up supervised learning algorithms, (3) reinforcement learning, and (4) the learning of complex stochastic models.

  1. Targeted Learning

    CERN Document Server

    van der Laan, Mark J

    2011-01-01

    The statistics profession is at a unique point in history. The need for valid statistical tools is greater than ever; data sets are massive, often measuring hundreds of thousands of measurements for a single subject. The field is ready to move towards clear objective benchmarks under which tools can be evaluated. Targeted learning allows (1) the full generalization and utilization of cross-validation as an estimator selection tool so that the subjective choices made by humans are now made by the machine, and (2) targeting the fitting of the probability distribution of the data toward the targe

  2. Learning Vaadin

    CERN Document Server

    Frankel, Nicolas

    2011-01-01

    This book begins with a tutorial on Vaadin 7, followed by a process of planning, analyzing, building, and deploying a fully functional RIA while covering troubleshooting details along the way, making it an invaluable resource for answers to all your Vaadin questions. If you are a Java developer with some experience in Java web development and want to enter the world of Rich Internet Applications this technology and book are ideal for you. Learning Vaadin will be perfect as your next step towards building eye-candy dynamic web applications on a Java-based platform.

  3. Learning Cypher

    CERN Document Server

    Panzarino, Onofrio

    2014-01-01

    An easy-to-follow guide full of tips and examples of real-world applications. In each chapter, a thorough example will show you the concepts in action, followed by a detailed explanation.This book is intended for those who want to learn how to create, query, and maintain a graph database, or who want to migrate to a graph database from SQL. It would be helpful to have some familiarity with Java and/or SQL, but no prior experience is required.

  4. Learning Perl

    CERN Document Server

    Schwartz, Randal; Phoenix, Tom

    2011-01-01

    If you're just getting started with Perl, this is the book you want-whether you're a programmer, system administrator, or web hacker. Nicknamed "the Llama" by two generations of users, this bestseller closely follows the popular introductory Perl course taught by the authors since 1991. This 6th edition covers recent changes to the language up to version 5.14. Perl is suitable for almost any task on almost any platform, from short fixes to complete web applications. Learning Perl teaches you the basics and shows you how to write programs up to 128 lines long-roughly the size of 90% of the Pe

  5. Learning scikit-learn machine learning in Python

    CERN Document Server

    Garreta, Raúl

    2013-01-01

    The book adopts a tutorial-based approach to introduce the user to Scikit-learn.If you are a programmer who wants to explore machine learning and data-based methods to build intelligent applications and enhance your programming skills, this the book for you. No previous experience with machine-learning algorithms is required.

  6. Technology Enhanced Learning

    NARCIS (Netherlands)

    Klemke, Roland; Specht, Marcus

    2013-01-01

    Klemke, R., & Specht, M. (2013, 26-27 September). Technology Enhanced Learning. Presentation at the fourth international conference on eLearning (eLearning 2013), Belgrade, Serbia. http://econference.metropolitan.ac.rs/

  7. Mobile Inquiry Based Learning

    NARCIS (Netherlands)

    Specht, Marcus

    2012-01-01

    Specht, M. (2012, 8 November). Mobile Inquiry Based Learning. Presentation given at the Workshop "Mobile inquiry-based learning" at the Mobile Learning Day 2012 at the Fernuniversität Hagen, Hagen, Germany.

  8. Learning and Memory

    OpenAIRE

    1999-01-01

    Under various circumstances and in different species the outward expression of learning varies considerably, and this has led to the classification of different categories of learning. Just as there is no generally agreed on definition of learning, there is no one system of classification. Types of learning commonly recognized are: Habituation, sensitization, classical conditioning, operant conditioning, trial and error, taste aversion, latent learning, cultural learning, imprinting, insight ...

  9. Toward Learning Teams

    DEFF Research Database (Denmark)

    Hoda, Rashina; Babb, Jeff; Nørbjerg, Jacob

    2013-01-01

    to sacrifice learning-focused practices. Effective learning under pressure involves conscious efforts to implement original agile practices such as retrospectives and adapted strategies such as learning spikes. Teams, their management, and customers must all recognize the importance of creating learning teams......Today's software development challenges require learning teams that can continuously apply new engineering and management practices, new and complex technical skills, cross-functional skills, and experiential lessons learned. The pressure of delivering working software often forces software teams...

  10. Greedy Deep Dictionary Learning

    OpenAIRE

    Tariyal, Snigdha; Majumdar, Angshul; Singh, Richa; Vatsa, Mayank

    2016-01-01

    In this work we propose a new deep learning tool called deep dictionary learning. Multi-level dictionaries are learnt in a greedy fashion, one layer at a time. This requires solving a simple (shallow) dictionary learning problem, the solution to this is well known. We apply the proposed technique on some benchmark deep learning datasets. We compare our results with other deep learning tools like stacked autoencoder and deep belief network; and state of the art supervised dictionary learning t...

  11. Learning Networks for Professional Development & Lifelong Learning

    NARCIS (Netherlands)

    Sloep, Peter

    2009-01-01

    Sloep, P. B. (2009). Learning Networks for Professional Development & Lifelong Learning. Presentation at a NeLLL seminar with Etienne Wenger held at the Open Universiteit Nederland. September, 10, 2009, Heerlen, The Netherlands.

  12. Use of blended learning in workplace learning

    DEFF Research Database (Denmark)

    Georgsen, Marianne; Løvstad, Charlotte Vange

    2014-01-01

    -based teaching materials. This paper presents the experiences of this particular project, and goes on to discuss the following points: • The blended learning design – use of IT for teaching, learning and communication • Digital learning materials – principals of design and use • Work place learning and learning......In 2014, a new system has been put in place for the inspection and approval of social welfare institutions in Denmark. In as little as 10 weeks, 330 new employees in five regional centres participated in an introductory course, designed as work place learning with extensive use of e-learning and IT...... from work – the interplay between experiences of the learner and the curriculum of the program •The approach taken to customising the e-learning design to the needs and demands of a particular case....

  13. Learning Design Development for Blended Learning

    DEFF Research Database (Denmark)

    Hansen, Janne Saltoft

    Learning design development for blended learning We started implementing Blackboard at Aarhus University in 2013. At the Health Faculty Blackboard replaced AULA which was a LMS with functionality for file distribution and only a vague focus on learning tools. Most teachers therefore had...... no experiences with blended leaning and technology supported out-of-class activities. At the pedagogical unit at the Health faculty we wanted to follow the Blackboard implementation with pedagogical tools for learning design to evolve the pedagogical use of the system. We needed to make development of blended...... learning courses easier for the teachers and also ensure quality in the courses. This poster describes the process from development of the learning design to implementation of the learning design at the faculty: 1. How to place demands on a learning design-model and how to develop and use such a model. 2...

  14. Judgments of Learning in Collaborative Learning Environments

    NARCIS (Netherlands)

    Helsdingen, Anne

    2010-01-01

    Helsdingen, A. S. (2010, March). Judgments of Learning in Collaborative Learning Environments. Poster presented at the 1st International Air Transport and Operations Symposium (ATOS 2010), Delft, The Netherlands: Delft University of Technology.

  15. Learning design guided learning analytics in MOOCs

    NARCIS (Netherlands)

    Brouns, Francis; Firssova, Olga

    2016-01-01

    Poster presentation for our paper Brouns, F., & Firssova, O. (2016, October).The role of learning design and learning analytics in MOOCs. Paper presented at 9th EDEN Research Workshop, Oldenburg, Germany.

  16. Networked professional learning

    NARCIS (Netherlands)

    Sloep, Peter

    2013-01-01

    Sloep, P. B. (2013). Networked professional learning. In A. Littlejohn, & A. Margaryan (Eds.), Technology-enhanced Professional Learning: Processes, Practices and Tools (pp. 97–108). London: Routledge.

  17. Resonant learning

    DEFF Research Database (Denmark)

    Lindvang, Charlotte

    2013-01-01

    -experience and personal therapy in training, first and foremost from the students’ perspective. The author focuses on presenting the qualitative part of her research which namely addresses the students’ experiences. Semi-structured qualitative interviews and qualitative music analyses were conducted, using a hermeneutic...... approach. The informants were nine music therapy students from Aalborg University, enrolled in the fifth year of their Master’s degree training programme. They were asked to bring a recording of an improvisation of their own choice to the interview. The qualitative data collection of text and music......The article presents a part of the authors PhD-study in music therapy about self-experiential training and the development of music therapeutic competencies. One of the purposes of the study was to explore and generate understanding and insight into the phenomena of learning through self...

  18. Blended Learning: An Innovative Approach

    Science.gov (United States)

    Lalima; Dangwal, Kiran Lata

    2017-01-01

    Blended learning is an innovative concept that embraces the advantages of both traditional teaching in the classroom and ICT supported learning including both offline learning and online learning. It has scope for collaborative learning; constructive learning and computer assisted learning (CAI). Blended learning needs rigorous efforts, right…

  19. Brain Research: Implications for Learning.

    Science.gov (United States)

    Soares, Louise M.; Soares, Anthony T.

    Brain research has illuminated several areas of the learning process: (1) learning as association; (2) learning as reinforcement; (3) learning as perception; (4) learning as imitation; (5) learning as organization; (6) learning as individual style; and (7) learning as brain activity. The classic conditioning model developed by Pavlov advanced…

  20. Blended Learning in Personalized Assistive Learning Environments

    Science.gov (United States)

    Marinagi, Catherine; Skourlas, Christos

    2013-01-01

    In this paper, the special needs/requirements of disabled students and cost-benefits for applying blended learning in Personalized Educational Learning Environments (PELE) in Higher Education are studied. The authors describe how blended learning can form an attractive and helpful framework for assisting Deaf and Hard-of-Hearing (D-HH) students to…

  1. LEARNING ABOUT LEARNING, A CONFERENCE REPORT.

    Science.gov (United States)

    BRUNER, JEROME

    TO EXPLORE THE NATURE OF THE LEARNING PROCESS, THREE IMPORTANT PROBLEM AREAS WERE STUDIED. STUDIES IN THE FIRST AREA, ATTITUDINAL AND AFFECTIVE SKILLS, ARE CONCERNED WITH INDUCING A CHILD TO LEARN AND SUSTAINING HIS ATTENTION. STUDIES IN THE SECOND AREA, COGNITIVE SKILLS, SOUGHT TO DISCOVER WHETHER GENERAL IDEAS AND SKILLS CAN BE LEARNED IN SUCH A…

  2. When Learning Analytics Meets E-Learning

    Science.gov (United States)

    Czerkawski, Betul C.

    2015-01-01

    While student data systems are nothing new and most educators have been dealing with student data for many years, learning analytics has emerged as a new concept to capture educational big data. Learning analytics is about better understanding of the learning and teaching process and interpreting student data to improve their success and learning…

  3. Learning Networks for Professional Development & Lifelong Learning

    NARCIS (Netherlands)

    Brouns, Francis; Sloep, Peter

    2009-01-01

    Brouns, F., & Sloep, P. B. (2009). Learning Networks for Professional Development & Lifelong Learning. Presentation of the Learning Network Programme for a Korean delegation of Chonnam National University and Dankook University (researchers dr. Jeeheon Ryu and dr. Minjeong Kim and a Group of PhD and

  4. Stimulating Deep Learning Using Active Learning Techniques

    Science.gov (United States)

    Yew, Tee Meng; Dawood, Fauziah K. P.; a/p S. Narayansany, Kannaki; a/p Palaniappa Manickam, M. Kamala; Jen, Leong Siok; Hoay, Kuan Chin

    2016-01-01

    When students and teachers behave in ways that reinforce learning as a spectator sport, the result can often be a classroom and overall learning environment that is mostly limited to transmission of information and rote learning rather than deep approaches towards meaningful construction and application of knowledge. A group of college instructors…

  5. Learning Analytics for Networked Learning Models

    Science.gov (United States)

    Joksimovic, Srecko; Hatala, Marek; Gaševic, Dragan

    2014-01-01

    Teaching and learning in networked settings has attracted significant attention recently. The central topic of networked learning research is human-human and human-information interactions occurring within a networked learning environment. The nature of these interactions is highly complex and usually requires a multi-dimensional approach to…

  6. Facilitating Learning Organizations. Making Learning Count.

    Science.gov (United States)

    Marsick, Victoria J.; Watkins, Karen E.

    This book offers advice to facilitators and change agents who wish to build systems-level learning to create knowledge that can be used to gain a competitive advantage. Chapter 1 describes forces driving companies to build, sustain, and effectively use systems-level learning and presents and links a working definition of the learning organization…

  7. Online transfer learning with extreme learning machine

    Science.gov (United States)

    Yin, Haibo; Yang, Yun-an

    2017-05-01

    In this paper, we propose a new transfer learning algorithm for online training. The proposed algorithm, which is called Online Transfer Extreme Learning Machine (OTELM), is based on Online Sequential Extreme Learning Machine (OSELM) while it introduces Semi-Supervised Extreme Learning Machine (SSELM) to transfer knowledge from the source to the target domain. With the manifold regularization, SSELM picks out instances from the source domain that are less relevant to those in the target domain to initialize the online training, so as to improve the classification performance. Experimental results demonstrate that the proposed OTELM can effectively use instances in the source domain to enhance the learning performance.

  8. Professional learning versus interprofessional learning

    DEFF Research Database (Denmark)

    Nielsen, Cathrine Sand

    2014-01-01

    to improve quality in the Danish healthcare system (1). Cooperation between patients and professionals is challenged when patients are transferred between department, hospitals or sectors (2). Sharing and developing knowledge inter-professionally and in particular across sectors is inadequate (3......, which is necessary for development of the future undergraduate health professional education programmes. The PhD project intends to generate knowledge of: - the contributions of InterTværs to the quality of future health professional education programmes and to the future healthcare system....... The transition challenges in the healthcare system do not seem to only affect patients and knowledge, but also the students and learning. References: (1) Institute for Quality and Accreditation in Healthcare. 2012. The Danish Healthcare Quality Programme. Accreditation Standards for Hospitals (2) Siemsen IMD...

  9. When does social learning become cultural learning?

    Science.gov (United States)

    Heyes, Cecilia

    2017-03-01

    Developmental research on selective social learning, or 'social learning strategies', is currently a rich source of information about when children copy behaviour, and who they prefer to copy. It also has the potential to tell us when and how human social learning becomes cultural learning; i.e. mediated by psychological mechanisms that are specialized, genetically or culturally, to promote cultural inheritance. However, this review article argues that, to realize its potential, research on the development of selective social learning needs more clearly to distinguish functional from mechanistic explanation; to achieve integration with research on attention and learning in adult humans and 'dumb' animals; and to recognize that psychological mechanisms can be specialized, not only by genetic evolution, but also by associative learning and cultural evolution. © 2015 John Wiley & Sons Ltd.

  10. Records for learning

    DEFF Research Database (Denmark)

    Binder, Thomas

    2005-01-01

    The article present and discuss findings from a participatory development of new learning practices among intensive care nurses, with an emphasize on the role of place making in informal learning activities.......The article present and discuss findings from a participatory development of new learning practices among intensive care nurses, with an emphasize on the role of place making in informal learning activities....

  11. Mobile Learning Platform

    DEFF Research Database (Denmark)

    Annan, Nana Kofi; Ofori-Dwumfou, George; Falch, Morten

    2012-01-01

    on the first experiences gained by both teachers and students by asking the following questions: What are the perceptions of teachers on m-learning? What are the effects of m-learning on students? What does m-learning contribute to face-to-face teaching and learning? Questionnaires were administered...

  12. Students Engaged in Learning

    Science.gov (United States)

    Ismail, Emad A.; Groccia, James E.

    2018-01-01

    Engaging students in learning is a basic principle of effective undergraduate education. Outcomes of engaging students include meaningful learning experiences and enhanced skills in all learning domains. This chapter reviews the influence of engaging students in different forms of active learning on cognitive, psychomotor, and affective skill…

  13. Cultural Learning Redux

    Science.gov (United States)

    Tomasello, Michael

    2016-01-01

    M. Tomasello, A. Kruger, and H. Ratner (1993) proposed a theory of cultural learning comprising imitative learning, instructed learning, and collaborative learning. Empirical and theoretical advances in the past 20 years suggest modifications to the theory; for example, children do not just imitate but overimitate in order to identify and…

  14. Teaching for Deep Learning

    Science.gov (United States)

    Smith, Tracy Wilson; Colby, Susan A.

    2007-01-01

    The authors have been engaged in research focused on students' depth of learning as well as teachers' efforts to foster deep learning. Findings from a study examining the teaching practices and student learning outcomes of sixty-four teachers in seventeen different states (Smith et al. 2005) indicated that most of the learning in these classrooms…

  15. Culture and Organizational Learning

    NARCIS (Netherlands)

    Cook, N.; Yanow, D.

    2011-01-01

    Traditionally, theories of organizational learning have taken one of two approaches that share a common characterization of learning but differ in focus. One approach focuses on learning by individuals in organizational contexts; the other, on individual learning as a model for organizational

  16. Active Learning Methods

    Science.gov (United States)

    Zayapragassarazan, Z.; Kumar, Santosh

    2012-01-01

    Present generation students are primarily active learners with varied learning experiences and lecture courses may not suit all their learning needs. Effective learning involves providing students with a sense of progress and control over their own learning. This requires creating a situation where learners have a chance to try out or test their…

  17. Algorithms for Reinforcement Learning

    CERN Document Server

    Szepesvari, Csaba

    2010-01-01

    Reinforcement learning is a learning paradigm concerned with learning to control a system so as to maximize a numerical performance measure that expresses a long-term objective. What distinguishes reinforcement learning from supervised learning is that only partial feedback is given to the learner about the learner's predictions. Further, the predictions may have long term effects through influencing the future state of the controlled system. Thus, time plays a special role. The goal in reinforcement learning is to develop efficient learning algorithms, as well as to understand the algorithms'

  18. Rethinking e-learning

    DEFF Research Database (Denmark)

    Bang, Jørgen; Dalsgaard, Christian

    2006-01-01

    “Technology alone does not deliver educational success. It only becomes valuable in education if learners and teachers can do something useful with it” (E-Learning: The Partnership Challenge, 2001, p. 24). This quotation could be used as a bon mot for this chapter. Our main goal is to rethink e-learning...... by shifting the focus of attention from learning resources (learning objects) to learning activities, which also implies a refocusing of the pedagogical discussion of the learning process.Firstly, we try to identify why e-learning has not been able to deliver the educational results as expected five years ago...

  19. Lessons Learned

    Directory of Open Access Journals (Sweden)

    Amanda Phelan BNS, MSc, PhD

    2015-03-01

    Full Text Available The public health nurses’ scope of practice explicitly includes child protection within their role, which places them in a prime position to identify child protection concerns. This role compliments that of other professions and voluntary agenices who work with children. Public health nurses are in a privileged position as they form a relationship with the child’s parent(s/guardian(s and are able to see the child in its own environment, which many professionals cannot. Child protection in Ireland, while influenced by other countries, has progressed through a distinct pathway that streamlined protocols and procedures. However, despite the above serious failures have occurred in the Irish system, and inquiries over the past 20 years persistently present similar contributing factors, namely, the lack of standardized and comprehensive service responses. Moreover, poor practice is compounded by the lack of recognition of the various interactional processes taking place within and between the different agencies of child protection, leading to psychological barriers in communication. This article will explore the lessons learned for public health nurses practice in safeguarding children in the Republic of Ireland.

  20. Learning tinnitus

    Science.gov (United States)

    van Hemmen, J. Leo

    Tinnitus, implying the perception of sound without the presence of any acoustical stimulus, is a chronic and serious problem for about 2% of the human population. In many cases, tinnitus is a pitch-like sensation associated with a hearing loss that confines the tinnitus frequency to an interval of the tonotopic axis. Even in patients with a normal audiogram the presence of tinnitus may be associated with damage of hair-cell function in this interval. It has been suggested that homeostatic regulation and, hence, increase of activity leads to the emergence of tinnitus. For patients with hearing loss, we present spike-timing-dependent Hebbian plasticity (STDP) in conjunction with homeostasis as a mechanism for ``learning'' tinnitus in a realistic neuronal network with tonotopically arranged synaptic excitation and inhibition. In so doing we use both dynamical scaling of the synaptic strengths and altering the resting potential of the cells. The corresponding simulations are robust to parameter changes. Understanding the mechanisms of tinnitus induction, such as here, may help improving therapy. Work done in collaboration with Julie Goulet and Michael Schneider. JLvH has been supported partially by BCCN - Munich.

  1. Learning after acquired brain injury. Learning the hard way

    NARCIS (Netherlands)

    Boosman, H.

    2015-01-01

    Background: When the brain has suffered damage, the learning process can be considerably disturbed. Brain damage can influence what is learned, but also how learning takes place. What patients can learn can be viewed in terms of ‘learning ability’ and how patients learn in terms of ‘learning style’.

  2. Interpretable Active Learning

    OpenAIRE

    Phillips, Richard L.; Chang, Kyu Hyun; Friedler, Sorelle A.

    2017-01-01

    Active learning has long been a topic of study in machine learning. However, as increasingly complex and opaque models have become standard practice, the process of active learning, too, has become more opaque. There has been little investigation into interpreting what specific trends and patterns an active learning strategy may be exploring. This work expands on the Local Interpretable Model-agnostic Explanations framework (LIME) to provide explanations for active learning recommendations. W...

  3. e-Learning Mathematics

    OpenAIRE

    Almanasreh, Hasan

    2017-01-01

    This study concerns the use of e-learning in the educational system shedding the light on its advantages and disadvantages, and analyzing its applicability either partially or totally. From mathematical perspectives, theories are developed to test the courses tendency to online transformation. This leads to a new trend of learning, the offline-online-offline learning (fnf-learning), it merges e-learning mode with the traditional orientation of education. The derivation of the new trend is bas...

  4. Learning Theories In Instructional Multimedia For English Learning

    OpenAIRE

    Farani, Rizki

    2016-01-01

    Learning theory is the concept of human learning. This concept is one of the important components in instructional for learning, especially English learning. English subject becomes one of important subjects for students but learning English needs specific strategy since it is not our vernacular. Considering human learning process in English learning is expected to increase students' motivation to understand English better. Nowadays, the application of learning theories in English learning ha...

  5. Designing Learning Resources in Synchronous Learning Environments

    DEFF Research Database (Denmark)

    Christiansen, Rene B

    2015-01-01

    Computer-mediated Communication (CMC) and synchronous learning environments offer new solutions for teachers and students that transcend the singular one-way transmission of content knowledge from teacher to student. CMC makes it possible not only to teach computer mediated but also to design...... and create new learning resources targeted to a specific group of learners. This paper addresses the possibilities of designing learning resources within synchronous learning environments. The empirical basis is a cross-country study involving students and teachers in primary schools in three Nordic...... Countries (Denmark, Sweden and Norway). On the basis of these empirical studies a set of design examples is drawn with the purpose of showing how the design fulfills the dual purpose of functioning as a remote, synchronous learning environment and - using the learning materials used and recordings...

  6. Multimodal sequence learning.

    Science.gov (United States)

    Kemény, Ferenc; Meier, Beat

    2016-02-01

    While sequence learning research models complex phenomena, previous studies have mostly focused on unimodal sequences. The goal of the current experiment is to put implicit sequence learning into a multimodal context: to test whether it can operate across different modalities. We used the Task Sequence Learning paradigm to test whether sequence learning varies across modalities, and whether participants are able to learn multimodal sequences. Our results show that implicit sequence learning is very similar regardless of the source modality. However, the presence of correlated task and response sequences was required for learning to take place. The experiment provides new evidence for implicit sequence learning of abstract conceptual representations. In general, the results suggest that correlated sequences are necessary for implicit sequence learning to occur. Moreover, they show that elements from different modalities can be automatically integrated into one unitary multimodal sequence. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Transformative learning spaces

    DEFF Research Database (Denmark)

    Maslo, Elina

    Despite rapid development of learning theory in general and language learning theory in particular in the last years, we still cannot provide an unequivocal answer on the question “why do individuals who presumably possess similar cognitive capacities for second language learning achieve such var......, Leo (2010). The ecology of language learning: Practice to theory, theory to practice. Procedia – Social and Behavioral Sciences. Elsevier......., social, personal, cultural, and historical world they live in (van Lier, 2000). People can learn when they discover possibilities for learning, which appear in this complex world – so called affordances (Gibson, 1979). This happens in the interaction between people and their environment on the basis...... to the different ways of interaction of cognitive, affective and social factors by different individuals. Learning stories, where multilingual individuals are telling about their subjective experiences in language learning in particular and learning in general, are constructed by using a special developed...

  8. Scikit-learn: Machine Learning in Python

    OpenAIRE

    Pedregosa, Fabian; Varoquaux, Gaël; Gramfort, Alexandre; Michel, Vincent; Thirion, Bertrand; Grisel, Olivier; Blondel, Mathieu; Prettenhofer, Peter; Weiss, Ron; Dubourg, Vincent; Vanderplas, Jake; Passos, Alexandre; Cournapeau, David; Brucher, Matthieu; Perrot, Matthieu

    2011-01-01

    International audience; Scikit-learn is a Python module integrating a wide range of state-of-the-art machine learning algorithms for medium-scale supervised and unsupervised problems. This package focuses on bringing machine learning to non-specialists using a general-purpose high-level language. Emphasis is put on ease of use, performance, documentation, and API consistency. It has minimal dependencies and is distributed under the simplified BSD license, encouraging its use in both academic ...

  9. Scikit-learn: Machine Learning in Python

    OpenAIRE

    Pedregosa, Fabian; Varoquaux, Gaël; Gramfort, Alexandre; Michel, Vincent; Thirion, Bertrand; Grisel, Olivier; Blondel, Mathieu; Louppe, Gilles; Prettenhofer, Peter; Weiss, Ron; Dubourg, Vincent; Vanderplas, Jake; Passos, Alexandre; Cournapeau, David; Brucher, Matthieu

    2012-01-01

    Scikit-learn is a Python module integrating a wide range of state-of-the-art machine learning algorithms for medium-scale supervised and unsupervised problems. This package focuses on bringing machine learning to non-specialists using a general-purpose high-level language. Emphasis is put on ease of use, performance, documentation, and API consistency. It has minimal dependencies and is distributed under the simplified BSD license, encouraging its use in both academic and commercial settings....

  10. Assessing learning at the workplace

    NARCIS (Netherlands)

    Evers, Arnoud

    2018-01-01

    • Defining learning at the workplace • Assessing learning at the workplace • Facilitating learning at the workplace: - Structure - Culture - Leadership - Personal factors • Conclusions • Discussion

  11. Mobile learning in medicine

    Science.gov (United States)

    Serkan Güllüoüǧlu, Sabri

    2013-03-01

    This paper outlines the main infrastructure for implicating mobile learning in medicine and present a sample mobile learning application for medical learning within the framework of mobile learning systems. Mobile technology is developing nowadays. In this case it will be useful to develop different learning environments using these innovations in internet based distance education. M-learning makes the most of being on location, providing immediate access, being connected, and acknowledges learning that occurs beyond formal learning settings, in places such as the workplace, home, and outdoors. Central to m-learning is the principle that it is the learner who is mobile rather than the device used to deliver m learning. The integration of mobile technologies into training has made learning more accessible and portable. Mobile technologies make it possible for a learner to have access to a computer and subsequently learning material and activities; at any time and in any place. Mobile devices can include: mobile phone, personal digital assistants (PDAs), personal digital media players (eg iPods, MP3 players), portable digital media players, portable digital multimedia players. Mobile learning (m-learning) is particularly important in medical education, and the major users of mobile devices are in the field of medicine. The contexts and environment in which learning occurs necessitates m-learning. Medical students are placed in hospital/clinical settings very early in training and require access to course information and to record and reflect on their experiences while on the move. As a result of this paper, this paper strives to compare and contrast mobile learning with normal learning in medicine from various perspectives and give insights and advises into the essential characteristics of both for sustaining medical education.

  12. Pervasive Learning Environments

    DEFF Research Database (Denmark)

    Hundebøl, Jesper; Helms, Niels Henrik

    2006-01-01

    The potentials of pervasive communication in learning within industry and education are right now being explored through different R&D projects. This paper outlines the background for and the possible learning potentials in what we describe as pervasive learning environments (PLE). PLE?s differ...... from virtual learning environments (VLE) primarily because in PLE?s the learning content is very much related to the actual context in which the learner finds himself. Two local (Denmark) cases illustrate various aspects of pervasive learning. One is the eBag, a pervasive digital portfolio used...

  13. Transnational Learning Processes

    DEFF Research Database (Denmark)

    Nedergaard, Peter

    This paper analyses and compares the transnational learning processes in the employment field in the European Union and among the Nordic countries. Based theoretically on a social constructivist model of learning and methodologically on a questionnaire distributed to the relevant participants......, a number of hypotheses concerning transnational learning processes are tested. The paper closes with a number of suggestions regarding an optimal institutional setting for facilitating transnational learning processes.Key words: Transnational learning, Open Method of Coordination, Learning, Employment......, European Employment Strategy, European Union, Nordic countries....

  14. Learning to Innovate

    DEFF Research Database (Denmark)

    Mei, Maggie

    the relationship between organizational learning and innovation creation in an organizational context. Taking a nuanced view of organizational learning, the dissertation investigates how three different organizational learning processes could affect innovation creation at the firm level and project level...... to the understanding of managing organizational learning for innovation creation at firms. The three studies in this dissertation show how three prominent organizational learning processes impact on firms’ innovation performance. Furthermore, the studies in this dissertation emphasize that there are limitation...... and boundary conditions for different organizational learning processes....

  15. e-Learning for Lifelong Learning in Denmark

    DEFF Research Database (Denmark)

    Buhl, Mie; Andreasen, Lars Birch

    2010-01-01

    The chapter on 'e-Learning for Lifelong Learning in Denmark' is part of an international White Paper, focusing on educational systems, describing status and characteristics and highlighting specific cases of e-learning and of lifelong learning....

  16. Lessons Learned

    International Nuclear Information System (INIS)

    Dougan, A.D.; Blair, S.

    2006-01-01

    LLNL turned in 5 Declaration Line Items (DLI's) in 2006. Of these, one was declared completed. We made some changes to streamline our process from 2005, used less money, time and fewer team members. This report is a description of what changes we made in 2006 and what we learned. Many of our core review team had changed from last year, including our Laboratory Director, the Facility safety and security representatives, our Division Leader, and the OPSEC Committee Chair. We were able to hand out an AP Manual to some of them, and briefed all newcomers to the AP process. We first went to the OPSEC Committee and explained what the Additional Protocol process would be for 2006 and solicited their help in locating declarable projects. We utilized the 'three questions' from the AP meeting last year. LLNL has no single place to locate all projects at the laboratory. We talked to Resource Managers and key Managers in the Energy and Environment Directorate and in the Nonproliferation Homeland and International Security Directorate to find applicable projects. We also talked to the Principal Investigators who had projects last year. We reviewed a list of CRADA's and LDRD projects given to us by the Laboratory Site Office. Talking to the PI's proved difficult because of vacation or travel schedules. We were never able to locate one PI in town. Fortunately, collateral information allowed us to screen out his project. We had no problems in downloading new versions of the DWA and DDA. It was helpful for both Steve Blair and Arden Dougan to have write privileges. During the time we were working on the project, we had to tag-team the work to allow for travel and vacation schedules. We had some difficulty locating an 'activities block' in the software. This was mentioned as something we needed to fix from our 2005 declaration. Evidently the Activities Block has been removed from the current version of the software. We also had trouble finding the DLI Detail Report, which we included

  17. Stealth Learning: Unexpected Learning Opportunities through Games

    Science.gov (United States)

    Sharp, Laura A.

    2012-01-01

    Educators across the country struggle to create engaging, motivating learning environments for their Net Gen students. These learners expect instant gratification that traditional lectures do not provide. This leaves educators searching for innovative ways to engage students in order to encourage learning. One solution is for educators to use…

  18. From E-learning to Blended Learning

    DEFF Research Database (Denmark)

    Hansen, Line Skov; Hansen, Ole

    2013-01-01

    . The project uses a ?capacity building strategy where new practice and skills are built through pedagogical interventions mostly designed as courses based on blended learning with a dialogue oriented and practice related team-work as an important part. Through this work the team learns how to use a specific...

  19. Generative Learning: Adults Learning within Ambiguity

    Science.gov (United States)

    Nicolaides, Aliki

    2015-01-01

    This study explored the extent to which ambiguity can serve as a catalyst for adult learning. The purpose of this study is to understand learning that is generated when encountering ambiguity agitated by the complexity of liquid modernity. "Ambiguity," in this study, describes an encounter with an appearance of reality that is at first…

  20. LEARNING HOW TO LEARN A LANGUAGE

    CERN Multimedia

    Language Training; Tel. 73127; Andrée Fontbonne; Tel. 72844

    2001-01-01

    This bilingual seminar is for anyone who would like to develop learning strategies and skills for learning a foreign language. Languages: French and English. Length: 3 days, 7 hours per day. Dates: 4, 5, 6 March 2002. Price: 460 CHF per person (for a group of 8 people). If you are interested, please enrol through our Web pages: http://cern.ch/Training

  1. LEARNING HOW TO LEARN A LANGUAGE

    CERN Multimedia

    Language Training; Tel. 73127; Andrée Fontbonne; Tel. 72844

    2001-01-01

    This bilingual seminar is for anyone who would like to develop learning strategies and skills for learning a foreign language. Languages: French and English. Length: 3 days, 7 hours per day. Dates: 5, 6, 7 November 2001. Price: 460 CHF per person (for a group of 8 people). If you are interested, please enrol through our Web pages: http://cern.ch/Training

  2. Constructivist learning theories and complex learning environments

    NARCIS (Netherlands)

    R-J. Simons; Dr. S. Bolhuis

    2004-01-01

    Learning theories broadly characterised as constructivist, agree on the importance to learning of the environment, but differ on what exactly it is that constitutes this importance. Accordingly, they also differ on the educational consequences to be drawn from the theoretical perspective. Cognitive

  3. Transformative Learning: Personal Empowerment in Learning Mathematics

    Science.gov (United States)

    Hassi, Marja-Liisa; Laursen, Sandra L.

    2015-01-01

    This article introduces the concept of personal empowerment as a form of transformative learning. It focuses on commonly ignored but enhancing elements of mathematics learning and argues that crucial personal resources can be essentially promoted by high engagement in mathematical problem solving, inquiry, and collaboration. This personal…

  4. Facilitating "Organisational Learning" in a "Learning Institution"

    Science.gov (United States)

    Lawler, Alan; Sillitoe, James

    2013-01-01

    The term "organisational learning" was popularised by Peter Senge in "The Fifth Discipline", his seminal book from 1990. Since then, the term has become widely accepted among those interested in organisational learning and change management. However, partly due to the somewhat ambiguous situation which arises in a university…

  5. Cooperative Learning as a Democratic Learning Method

    Science.gov (United States)

    Erbil, Deniz Gökçe; Kocabas, Ayfer

    2018-01-01

    In this study, the effects of applying the cooperative learning method on the students' attitude toward democracy in an elementary 3rd-grade life studies course was examined. Over the course of 8 weeks, the cooperative learning method was applied with an experimental group, and traditional methods of teaching life studies in 2009, which was still…

  6. Learning about Allergies

    Science.gov (United States)

    ... Videos for Educators Search English Español Learning About Allergies KidsHealth / For Kids / Learning About Allergies What's in ... in the spring. Why Do Some Kids Get Allergies? People may be born with a genetic (say: ...

  7. Pervasive Learning Environments

    DEFF Research Database (Denmark)

    Hundebøl, Jesper; Helms, Niels Henrik

    in schools. The other is moreover related to work based learning in that it foresees a community of practitioners accessing, sharing and adding to knowledge and learning objects held within a pervasive business intelligence system. Limitations and needed developments of these and other systems are discussed......Abstract: The potentials of pervasive communication in learning within industry and education are right know being explored through different R&D projects. This paper outlines the background for and the possible learning potentials in what we describe as pervasive learning environments (PLE). PLE......'s differ from virtual learning environments (VLE) primarily because in PLE's the learning content is very much related to the actual context in which the learner finds himself. Two local (Denmark) cases illustrate various aspects of pervasive learning. One is the eBag, a pervasive digital portfolio used...

  8. Learning by Doing.

    Science.gov (United States)

    Schettler, Joel

    2002-01-01

    Suggests that, as people become the key differentiation of competitive advantage, companies are turning to experiential learning programs to foster work force collaboration and cooperation. Discusses the history of experiential learning and its application in the workplace. (JOW)

  9. Learning Networks Distributed Environment

    NARCIS (Netherlands)

    Martens, Harrie; Vogten, Hubert; Koper, Rob; Tattersall, Colin; Van Rosmalen, Peter; Sloep, Peter; Van Bruggen, Jan; Spoelstra, Howard

    2005-01-01

    Learning Networks Distributed Environment is a prototype of an architecture that allows the sharing and modification of learning materials through a number of transport protocols. The prototype implements a p2p protcol using JXTA.

  10. Learning about Proteins

    Science.gov (United States)

    ... Fitness Diseases & Conditions Infections Drugs & Alcohol School & Jobs Sports Expert Answers (Q&A) Staying Safe Videos for Educators Search English Español Learning About Proteins KidsHealth / For Kids / Learning About Proteins What's in ...

  11. Learning in Practice

    DEFF Research Database (Denmark)

    Helth, Poula

    on theories of aesthetic performance and transformative learning, and on empirical studies through interventive methods within action research and ethnography. Transformative learning in my study has been developed based on aesthetic performance addressing leaders’ learning in practice. This kind of learning......The thesis presents the essence of my study of how leaders transform their practice through aesthetic performance. The background of the study is leaders' need for learning in and through practice, as an alternative to learning in classrooms and to leadership education programs. The study is based...... happens when leaders become aware of the potential for transformation of their leadership practice when they experiment with aesthetic performance integrated in a learning process. The greatest impact in relation to organisational transformation is, when leaders base their learning on a collective...

  12. MOOC Blended learning ontwikkelen

    NARCIS (Netherlands)

    Verjans, Steven

    2015-01-01

    Presentatie over het ontwerpen van leeractiviteiten (learning design) tijdens de zesde live sessie van de MOOC Blended learning ontwikkelen. Met gebruikmaking van presentatiematerialen van Diana Laurillard, Grainne Conole, Helen Beetham, Jos Fransen, Pieter Swager, Helen Keegan, Corinne Weisgerber.

  13. Social Structures for Learning

    NARCIS (Netherlands)

    I.M. Bogenrieder (Irma); B. Nooteboom (Bart)

    2001-01-01

    textabstractThis article investigates what learning groups there are in organizations, other than the familiar 'communities of practice'. It first develops an interdisciplinary theoretical framework for identifying, categorizing and understanding learning groups. For this, it employs a

  14. Learning about Carbohydrates

    Science.gov (United States)

    ... Videos for Educators Search English Español Learning About Carbohydrates KidsHealth / For Kids / Learning About Carbohydrates Print en ... source of energy for the body. What Are Carbohydrates? There are two major types of carbohydrates (or ...

  15. Preventing Learned Helplessness.

    Science.gov (United States)

    Hoy, Cheri

    1986-01-01

    To prevent learned helplessness in learning disabled students, teachers can share responsibilities with the students, train students to reinforce themselves for effort and self control, and introduce opportunities for changing counterproductive attitudes. (CL)

  16. Teaming up for learning

    NARCIS (Netherlands)

    Fransen, Jos

    2012-01-01

    Fransen, J. (2012). Teaming up for learning: Team effectiveness in collaborative learning in higher education (Doctoral dissertation). November, 16, 2012, Open University in the Netherlands (CELSTEC), Heerlen, The Netherlands.

  17. Teachability in Computational Learning

    OpenAIRE

    Shinohara, Ayumi; Miyano, Satoru

    1990-01-01

    This paper considers computationai learning from the viewpoint of teaching. We introduce a notion of teachability with which we establish a relationship between the learnability and teachability. We also discuss the complexity issues of a teacher in relation to learning.

  18. The sign learning theory

    African Journals Online (AJOL)

    KING OF DAWN

    The sign learning theory also holds secrets that could be exploited in accomplishing motor tasks. ... Introduction ... In his classic work: Cognitive Map in Rats and Men (1948),Tolman talked about five groups of experiments viz: latent learning ...

  19. Efficient Learning Design

    DEFF Research Database (Denmark)

    Godsk, Mikkel

    This paper presents the current approach to implementing educational technology with learning design at the Faculty of Science and Technology, Aarhus University, by introducing the concept of ‘efficient learning design’. The underlying hypothesis is that implementing learning design is more than...... engaging educators in the design process and developing teaching and learning, it is a shift in educational practice that potentially requires a stakeholder analysis and ultimately a business model for the deployment. What is most important is to balance the institutional, educator, and student...... perspectives and to consider all these in conjunction in order to obtain a sustainable, efficient learning design. The approach to deploying learning design in terms of the concept of efficient learning design, the catalyst for educational development, i.e. the learning design model and how it is being used...

  20. Pervasive Learning Environments

    DEFF Research Database (Denmark)

    Helms, Niels Henrik; Hundebøl, Jesper

    2006-01-01

    The potentials of pervasive communication in learning within industry and education are right know being explored through different R&D projects. This paper outlines the background for and the possible learning potentials in what we describe as pervasive learning environments (PLE). PLE's differ...... from virtual learning environments (VLE) primarily because in PLE's the learning content is very much related to the actual context in which the learner finds himself. Two local (Denmark) cases illustrate various aspects of pervasive learning. One is the eBag, a pervasive digital portfolio used...... in schools. The other is moreover related to work based learning in that it foresees a community of practitioners accessing, sharing and adding to knowledge and learning objects held within a pervasive business intelligence system. Limitations and needed developments of these and other systems are discussed...

  1. Learning Design Tools

    NARCIS (Netherlands)

    Griffiths, David; Blat, Josep; Garcia, Rocío; Vogten, Hubert; Kwong, KL

    2005-01-01

    Griffiths, D., Blat, J., Garcia, R., Vogten, H. & Kwong, KL. (2005). Learning Design Tools. In: Koper, R. & Tattersall, C., Learning Design: A Handbook on Modelling and Delivering Networked Education and Training (pp. 109-136). Berlin-Heidelberg: Springer Verlag.

  2. Genetic Science Learning Center

    Science.gov (United States)

    Genetic Science Learning Center Making science and health easy for everyone to understand Home News Our Team What We Do ... Collaboration Conferences Current Projects Publications Contact The Genetic Science Learning Center at The University of Utah is a ...

  3. Mobile Informal Learning

    NARCIS (Netherlands)

    Glahn, Christian; Börner, Dirk

    2010-01-01

    Glahn, C., & Börner, D. (2009). Mobile Informal Learning. Presented at Mobile Learning in Context Symposium at the Open University of the Netherlands. September, 11, 2009, Heerlen, The Netherlands: Open University of the Netherlands.

  4. Making Learning Meaningful.

    Science.gov (United States)

    Odom, A. Louis; Kelly, Paul V.

    1998-01-01

    Discusses two theories of cognitive development, Ausubel's theory of verbal learning and Piaget's development theory. Illustrates that both concept mapping and the learning cycle are rooted in these two theories. (DDR)

  5. New learning : three ways to learn in a new balance

    NARCIS (Netherlands)

    Simons, P.R.J.

    2000-01-01

    Because people are learning all the time, we need criteria that can help us distinguish between better and worse kinds of learning. Organizations and societies as well as the psychology of learning ask for new learning outcomes, new learning processes and new forms of instruction. New learning

  6. Learning about Learning: A Conundrum and a Possible Resolution

    Science.gov (United States)

    Barnett, Ronald

    2011-01-01

    What is it to learn in the modern world? We can identify four "learning epochs" through which our understanding of learning has passed: a metaphysical view; an empirical view; an experiential view; and, currently, a "learning-amid-contestation" view. In this last and current view, learning has its place in a world in which, the more one learns,…

  7. Effects of Cooperative E-Learning on Learning Outcomes

    Science.gov (United States)

    Yeh, Shang-Pao; Fu, Hsin-Wei

    2014-01-01

    This study aims to discuss the effects of E-Learning and cooperative learning on learning outcomes. E-Learning covers the dimensions of Interpersonal communication, abundant resources, Dynamic instruction, and Learning community; and, cooperative learning contains three dimensions of Cooperative motive, Social interaction, and Cognition…

  8. Learning, Play, and Your Newborn

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Learning, Play, and Your Newborn KidsHealth / For Parents / Learning, ... Some Other Ideas Print What Is My Newborn Learning? Play is the chief way that infants learn ...

  9. Supervised Learning for Dynamical System Learning.

    Science.gov (United States)

    Hefny, Ahmed; Downey, Carlton; Gordon, Geoffrey J

    2015-01-01

    Recently there has been substantial interest in spectral methods for learning dynamical systems. These methods are popular since they often offer a good tradeoff between computational and statistical efficiency. Unfortunately, they can be difficult to use and extend in practice: e.g., they can make it difficult to incorporate prior information such as sparsity or structure. To address this problem, we present a new view of dynamical system learning: we show how to learn dynamical systems by solving a sequence of ordinary supervised learning problems, thereby allowing users to incorporate prior knowledge via standard techniques such as L 1 regularization. Many existing spectral methods are special cases of this new framework, using linear regression as the supervised learner. We demonstrate the effectiveness of our framework by showing examples where nonlinear regression or lasso let us learn better state representations than plain linear regression does; the correctness of these instances follows directly from our general analysis.

  10. Immersive Learning Technologies

    Science.gov (United States)

    2009-08-20

    Immersive Learning Technologies Mr. Peter Smith Lead, ADL Immersive Learning Team 08/20/2009 Report Documentation Page Form ApprovedOMB No. 0704...to 00-00-2009 4. TITLE AND SUBTITLE Immersive Learning Technologies 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR...unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 Why Immersive Learning Technologies

  11. Learning a Second Language

    OpenAIRE

    Murphy, Caroline; Hermann, Charlotte; Andersen, Signe Hvalsøe; Grigalauskyte, Simona; Tolsgaard, Mads; Holmegaard, Thorbjørn; Hajaya, Zaedo Musa

    2013-01-01

    This study examines the concept of second language learning in Denmark with focus on how second language learners negotiate their identities in relation to language learning and integration. By investigating three language learners’ acquisition of Danish through key theories on the field of second language learning, focus is centred on the subjects’ lived experiences of the learning process within their everyday lives and in the classroom. Through interviews and observations it can be conclud...

  12. Social Structures for Learning

    OpenAIRE

    Bogenrieder, I.M.; Nooteboom, B.

    2001-01-01

    textabstractThis article investigates what learning groups there are in organizations, other than the familiar 'communities of practice'. It first develops an interdisciplinary theoretical framework for identifying, categorizing and understanding learning groups. For this, it employs a constructivist, interactionist theory of knowledge and learning. It employs elements of transaction cost theory and of social theory of trust. Transaction cost economics neglects learning and trust, but element...

  13. Pervasive e-learning

    DEFF Research Database (Denmark)

    Hundebøl, Jesper; Helms, Niels Henrik

    2009-01-01

    This article falls within planning, production and delivery of innovative learning resources. The establishment of pervasive learning environments is based on the successful combination and re-configuration of inter-connected sets of learning objects, databases and data-streams. The text presents...... a definition of Pervasive Learning Environments and discusses the pedagogical potentials and challenges in developing such environments with emphasis on context, new didactics, content and affordances....

  14. Evolving to organizational learning.

    Science.gov (United States)

    Bechtold, B L

    2000-02-01

    To transform in stride with the business changes, organizations need to think of development as "organizational learning" rather than "training." Companies need to manage learning as a strategic competitive advantage for current and future business rather than as a perk for individuals. To position themselves for success in a dynamic business environment, companies need to reframe their concept of learning and development to a mindset of organizational learning.

  15. LEADING THE LEARNING ORGANIZATION

    OpenAIRE

    Sapna Rijal

    2009-01-01

    Researchers have identified leadership as being one of the most important factors that influence the development of learning organization. They suggest that creating a collective vision of the future, empowering and developing employees so that they are better able to handle environmental challenges, modeling learning behavior and creating a learning environment, are crucial skills for leaders of learning organization. These roles are suitable to a transformational leader. Despite the potenti...

  16. Social learning in fish

    OpenAIRE

    Atton, Nicola

    2010-01-01

    Social learning is known to be a common phenomenon in fish, which they utilise under many different contexts, including foraging, mate-choice and migration. Here I review the literature on social learning in fish and present two studies. The first examines the ability of threespined sticklebacks to use social learning in the enhancement of food preferences. The second study examines the ability of both threespined sticklebacks and ninespined sticklebacks to use social learning in the avoidanc...

  17. Learning from prescribing errors

    OpenAIRE

    Dean, B

    2002-01-01

    

 The importance of learning from medical error has recently received increasing emphasis. This paper focuses on prescribing errors and argues that, while learning from prescribing errors is a laudable goal, there are currently barriers that can prevent this occurring. Learning from errors can take place on an individual level, at a team level, and across an organisation. Barriers to learning from prescribing errors include the non-discovery of many prescribing errors, lack of feedback to th...

  18. Microsoft Azure machine learning

    CERN Document Server

    Mund, Sumit

    2015-01-01

    The book is intended for those who want to learn how to use Azure Machine Learning. Perhaps you already know a bit about Machine Learning, but have never used ML Studio in Azure; or perhaps you are an absolute newbie. In either case, this book will get you up-and-running quickly.

  19. My Teaching Learning Philosophy

    Science.gov (United States)

    Punjani, Neelam Saleem

    2014-01-01

    The heart of teaching learning philosophy is the concept of nurturing students and teaching them in a way that creates passion and enthusiasm in them for a lifelong learning. According to Duke (1990) education is a practice of artful action where teaching learning process is considered as design and knowledge is considered as colours. Teaching…

  20. Enhancing learning with technology

    NARCIS (Netherlands)

    Specht, Marcus; Klemke, Roland

    2013-01-01

    Specht, M., & Klemke, R. (2013, 26-27 September). Enhancing Learning with Technology. In D. Milosevic (Ed.), Proceedings of the fourth international conference on eLearning (eLearning 2013) (pp. 37-45). Belgrade Metropolitan University, Belgrade, Serbia. http://econference.metropolitan.ac.rs/

  1. Deep Learning Policy Quantization

    NARCIS (Netherlands)

    van de Wolfshaar, Jos; Wiering, Marco; Schomaker, Lambertus

    2018-01-01

    We introduce a novel type of actor-critic approach for deep reinforcement learning which is based on learning vector quantization. We replace the softmax operator of the policy with a more general and more flexible operator that is similar to the robust soft learning vector quantization algorithm.

  2. Games for Learning

    Science.gov (United States)

    Gee, James Paul

    2013-01-01

    Today there is a great deal of interest in and a lot of hype about using video games in schools. Video games are a new silver bullet. Games can create good learning because they teach in powerful ways. The theory behind game-based learning is not really new, but a traditional and well-tested approach to deep and effective learning, often…

  3. Learning Probabilistic Decision Graphs

    DEFF Research Database (Denmark)

    Jaeger, Manfred; Dalgaard, Jens; Silander, Tomi

    2004-01-01

    efficient representations than Bayesian networks. In this paper we present an algorithm for learning PDGs from data. First experiments show that the algorithm is capable of learning optimal PDG representations in some cases, and that the computational efficiency of PDG models learned from real-life data...

  4. A learning space Odyssey

    NARCIS (Netherlands)

    Beckers, Ronald

    2016-01-01

    This dissertation addresses the alignment of learning space with higher education learning and teaching. Significant changes in higher education the past decades, such as increased information and communication technology (ICT) and new learning theories have resulted in the dilemma whether higher

  5. Learning in Organization

    Science.gov (United States)

    Palos, Ramona; Veres Stancovici, Vesna

    2016-01-01

    Purpose: This study aims at identifying the presence of the dimensions of learning capabilities and the characteristics of a learning organization within two companies in the field of services, as well as identifying the relationships between their learning capability and the organizational culture. Design/methodology/approach: This has been a…

  6. Learning Outcomes Report

    NARCIS (Netherlands)

    Stoyanov, Slavi; Spoelstra, Howard; Burgoyne, Louise; O’Tuathaigh, Colm

    2018-01-01

    Aim of the study The learning outcomes study, conducted as part of WP3 of the BioApp project, has as objectives: (a) generating a comprehensive list of the learning outcomes; (b) reaching an agreement on the scope and priority of the learning outcomes, and (c) making suggestions for the further

  7. Action Learning in China

    Science.gov (United States)

    Marquardt, Michael J.

    2015-01-01

    Action learning was introduced into China less than 20 years ago, but has rapidly become a valuable tool for organizations seeking to solve problems, develop their leaders, and become learning organizations. This article provides an historical overview of action learning in China, its cultural underpinnings, and five case studies. It concludes…

  8. Invited Reaction: Influences of Formal Learning, Personal Learning Orientation, and Supportive Learning Environment on Informal Learning

    Science.gov (United States)

    Cseh, Maria; Manikoth, Nisha N.

    2011-01-01

    As the authors of the preceding article (Choi and Jacobs, 2011) have noted, the workplace learning literature shows evidence of the complementary and integrated nature of formal and informal learning in the development of employee competencies. The importance of supportive learning environments in the workplace and of employees' personal learning…

  9. KARATE WITH CONSTRUCTIVE LEARNING

    Directory of Open Access Journals (Sweden)

    Srikrishna Karanam

    2012-02-01

    Full Text Available Any conventional learning process involves the traditional hierarchy of garnering of information and then recall gathered information. Constructive learning is an important research area having wide impact on teaching methods in education, learning theories, and plays a major role in many education reform movements. It is observed that constructive learning advocates the interconnection between emotions and learning. Human teachers identify the emotions of students with varying degrees of accuracy and can improve the learning rate of the students by motivating them. In learning with computers, computers also should be given the capability to recognize emotions so as to optimize the learning process. Image Processing is a very popular tool used in the process of establishing the theory of Constructive Learning. In this paper we use the Optical Flow computation in image sequences to analyze the accuracy of the moves of a karate player. We have used the Lucas-Kanade method for computing the optical flow in image sequences. A database consisting of optical flow images by a group of persons learning karate is formed and the learning rates are analyzed in order to main constructive learning. The contours of flow images are compared with the standard images and the error graphs are plotted. Analysis of the emotion of the amateur karate player is made by observing the error plots.

  10. Repurposing learning object components

    NARCIS (Netherlands)

    Verbert, K.; Jovanovic, J.; Gasevic, D.; Duval, E.; Meersman, R.

    2005-01-01

    This paper presents an ontology-based framework for repurposing learning object components. Unlike the usual practice where learning object components are assembled manually, the proposed framework enables on-the-fly access and repurposing of learning object components. The framework supports two

  11. Canadian Chefs' Workplace Learning

    Science.gov (United States)

    Cormier-MacBurnie, Paulette; Doyle, Wendy; Mombourquette, Peter; Young, Jeffrey D.

    2015-01-01

    Purpose: This paper aims to examine the formal and informal workplace learning of professional chefs. In particular, it considers chefs' learning strategies and outcomes as well as the barriers to and facilitators of their workplace learning. Design/methodology/approach: The methodology is based on in-depth, face-to-face, semi-structured…

  12. Learning: An Evolutionary Analysis

    Science.gov (United States)

    Swann, Joanna

    2009-01-01

    This paper draws on the philosophy of Karl Popper to present a descriptive evolutionary epistemology that offers philosophical solutions to the following related problems: "What happens when learning takes place?" and "What happens in human learning?" It provides a detailed analysis of how learning takes place without any direct transfer of…

  13. Guided Learning at Work.

    Science.gov (United States)

    Billett, Stephen

    2000-01-01

    Guided learning (questioning, diagrams/analogies, modeling, coaching) was studied through critical incident interviews in five workplaces. Participation in everyday work activities was the most effective contributor to workplace learning. Organizational readiness and the efficacy of guided learning in resolving novel tasks were also important. (SK)

  14. Adult Learning Assumptions

    Science.gov (United States)

    Baskas, Richard S.

    2011-01-01

    The purpose of this study is to examine Knowles' theory of andragogy and his six assumptions of how adults learn while providing evidence to support two of his assumptions based on the theory of andragogy. As no single theory explains how adults learn, it can best be assumed that adults learn through the accumulation of formal and informal…

  15. Learning analytics dashboard applications

    NARCIS (Netherlands)

    Verbert, K.; Duval, E.; Klerkx, J.; Govaerts, S.; Santos, J.L.

    2013-01-01

    This article introduces learning analytics dashboards that visualize learning traces for learners and teachers. We present a conceptual framework that helps to analyze learning analytics applications for these kinds of users. We then present our own work in this area and compare with 15 related

  16. Innovazione nel mobile learning

    Directory of Open Access Journals (Sweden)

    Immaculada Arnedillo-Sànchez

    2008-01-01

    Full Text Available Descrizione, da una prospettiva europea, dell’innovazione nel settore del mobile learning e l’utilizzabilita’ del mobile learning in contesti educativi. Vengono illustrate i principali progetti europei di m-learning e si esamina le prospettive pedagogiche e teoriche relative al campo.

  17. Under Threes' Mathematical Learning

    Science.gov (United States)

    Franzén, Karin

    2015-01-01

    The article focuses on mathematics for toddlers in preschool, with the aim of challenging a strong learning discourse that mainly focuses on cognitive learning. By devoting more attention to other perspectives on learning, the hope is to better promote children's early mathematical development. Sweden is one of few countries to have a curriculum…

  18. Learning from Errors

    Science.gov (United States)

    Metcalfe, Janet

    2017-01-01

    Although error avoidance during learning appears to be the rule in American classrooms, laboratory studies suggest that it may be a counterproductive strategy, at least for neurologically typical students. Experimental investigations indicate that errorful learning followed by corrective feedback is beneficial to learning. Interestingly, the…

  19. Learning from Errors

    OpenAIRE

    Martínez-Legaz, Juan Enrique; Soubeyran, Antoine

    2003-01-01

    We present a model of learning in which agents learn from errors. If an action turns out to be an error, the agent rejects not only that action but also neighboring actions. We find that, keeping memory of his errors, under mild assumptions an acceptable solution is asymptotically reached. Moreover, one can take advantage of big errors for a faster learning.

  20. Learning from Failed Decisions

    Science.gov (United States)

    Nutt, Paul C.

    2010-01-01

    The consequences and dilemmas posed by learning issues for decision making are discussed. Learning requires both awareness of barriers and a coping strategy. The motives to hold back information essential for learning stem from perverse incentives, obscure outcomes, and the hindsight bias. There is little awareness of perverse incentives that…

  1. E-Learning Agents

    Science.gov (United States)

    Gregg, Dawn G.

    2007-01-01

    Purpose: The purpose of this paper is to illustrate the advantages of using intelligent agents to facilitate the location and customization of appropriate e-learning resources and to foster collaboration in e-learning environments. Design/methodology/approach: This paper proposes an e-learning environment that can be used to provide customized…

  2. How People Learn in an Asynchronous Online Learning Environment: The Relationships between Graduate Students' Learning Strategies and Learning Satisfaction

    Science.gov (United States)

    Choi, Beomkyu

    2016-01-01

    The purpose of this study was to examine the relationships between learners' learning strategies and learning satisfaction in an asynchronous online learning environment. In an attempt to shed some light on how people learn in an online learning environment, one hundred and sixteen graduate students who were taking online learning courses…

  3. A Flow of Entrepreneurial Learning Elements in Experiential Learning Settings

    DEFF Research Database (Denmark)

    Ramsgaard, Michael Breum; Christensen, Marie Ernst

    This paper explored the concept of learning in an experiential learning setting and whether the learning process can be understood as a flow of learning factors influencing the outcome. If many constituting factors lead to the development of learning outcomes, there might need to be developed...... that are a part of experiential learning settings and curriculum development....... a differentiated approach to facilitate experiential learning. Subsequently the paper investigated how facilitators of learning processes can design a learning space where the boundary of what is expected from the learner is challenged. In other words the aim was to explore the transformative learning processes...

  4. The big picture : What the Baltics may learn from Ireland's success story / Michael Bourke ; interv. Maris Biezaitis

    Index Scriptorium Estoniae

    Bourke, Michael

    2002-01-01

    Ilmunud ka: Baltiiskii kurss 2002/Zima/Vesna nr. 20 lk. 14-17. Iirimaa aukonsul Lätis, Michael Joseph Bourke arutleb Iirimaa majandusedu teemal ning pakub välja, mida Baltimaad saaksid sellest õppida. Tabel, diagramm. Lisa

  5. Learning in context

    DEFF Research Database (Denmark)

    Keiding, Tina Bering

    2007-01-01

    This article offers a re-description of the concept of learning context. Drawing on Niklas Luhmann and Gregory Bateson it suggests an alternative to situated, social learning and activity theory. The conclusion is that learning context designates an individual's reconstruction of the environment...... through contingent handling of differences and that the individual emerge as learning through the actual construction. Selection of differences is influenced by the learner's actual knowledge, the nature of the environment and the current horizon of meaning in which the current adaptive perspective...... becomes a significant factor. The re-description contributes to didaktik  through renewed understandings of participants' background in teaching and learning....

  6. Political learning among youth

    DEFF Research Database (Denmark)

    Solhaug, Trond; Kristensen, Niels Nørgaard

    2014-01-01

    This article focuses on students’ first political learning and explores the research question, what dynamic patterns of political learning can be explored among a selection of young, diverse Danish students’ first political interests? The authors use theories of learning in their analytical......, but are active constructors of their political life. Their emotions and social environment are highly important for their political orientation. It is recommended that further research focus on dynamic learning and on arenas for political learning rather than on “single agent studies.” Recommendations...

  7. Quantum machine learning.

    Science.gov (United States)

    Biamonte, Jacob; Wittek, Peter; Pancotti, Nicola; Rebentrost, Patrick; Wiebe, Nathan; Lloyd, Seth

    2017-09-13

    Fuelled by increasing computer power and algorithmic advances, machine learning techniques have become powerful tools for finding patterns in data. Quantum systems produce atypical patterns that classical systems are thought not to produce efficiently, so it is reasonable to postulate that quantum computers may outperform classical computers on machine learning tasks. The field of quantum machine learning explores how to devise and implement quantum software that could enable machine learning that is faster than that of classical computers. Recent work has produced quantum algorithms that could act as the building blocks of machine learning programs, but the hardware and software challenges are still considerable.

  8. Rethinking expansive learning

    DEFF Research Database (Denmark)

    Kolbæk, Ditte; Lundh Snis, Ulrika

    Abstract: This paper analyses an online community of master’s students taking a course in ICT and organisational learning. The students initiated and facilitated an educational design for organisational learning called Proactive Review in the organisation where they are employed. By using an online...... discussion forum on Google groups, they created new ways of reflecting and learning. We used netnography to select qualitative postings from the online community and expansive learning concepts for data analysis. The findings show how students changed practices of organisational learning...

  9. Machine learning with R

    CERN Document Server

    Lantz, Brett

    2013-01-01

    Written as a tutorial to explore and understand the power of R for machine learning. This practical guide that covers all of the need to know topics in a very systematic way. For each machine learning approach, each step in the process is detailed, from preparing the data for analysis to evaluating the results. These steps will build the knowledge you need to apply them to your own data science tasks.Intended for those who want to learn how to use R's machine learning capabilities and gain insight from your data. Perhaps you already know a bit about machine learning, but have never used R; or

  10. Learning Analytics for Supporting Seamless Language Learning Using E-Book with Ubiquitous Learning System

    Science.gov (United States)

    Mouri, Kousuke; Uosaki, Noriko; Ogata, Hiroaki

    2018-01-01

    Seamless learning has been recognized as an effective learning approach across various dimensions including formal and informal learning contexts, individual and social learning, and physical world and cyberspace. With the emergence of seamless learning, the majority of the current research focuses on realizing a seamless learning environment at…

  11. Gani Odutoku ' Dialogu with Mona Lisa: Interrogating Implications of ...

    African Journals Online (AJOL)

    ... exists in the interface that Africa and Europe shares, African nationalist efforts must combine concepts of Negritude and Tigritude to reinvent a new African consciousness that rises beyond the ashes of past debilitating conditions. Key words- Euro-African Interface, Negritude, Tigritude, Implication, Pan-Africanism ...

  12. An Examination of Acceptable Navigation Accuracy for LISA Orbits

    National Research Council Canada - National Science Library

    Smythe, Reid W

    2007-01-01

    .... Preliminary analysis indicated the values of each parameter varied sinusoidally, and increasing the initial error conditions tended to reduce the time each parameter fell within the acceptable tolerance values...

  13. The search for massive black hole binaries with LISA

    International Nuclear Information System (INIS)

    Cornish, Neil J; Porter, Edward K

    2007-01-01

    In this work we focus on the search and detection of massive black hole binary (MBHB) systems, including systems at high redshift. As well as expanding on previous works where we used a variant of Markov chain Monte Carlo (MCMC), called Metropolis-Hastings Monte Carlo, with simulated annealing, we introduce a new search method based on frequency annealing which leads to a more rapid and robust detection. We compare the two search methods on systems where we do and do not see the merger of the black holes. In the non-merger case, we also examine the posterior distribution exploration using a 7D MCMC algorithm. We demonstrate that this method is effective in dealing with the high correlations between parameters, has a higher acceptance rate than previously proposed methods and produces posterior distribution functions that are close to the prediction from the Fisher information matrix. Finally, after carrying out searches where there is only one binary in the data stream, we examine the case where two black hole binaries are present in the same data stream. We demonstrate that our search algorithm can accurately recover both binaries, and more importantly showing that we can safely extract the MBHB sources without contaminating the rest of the data stream

  14. Cancellation of differential accelerations for the LISA spacecraft

    International Nuclear Information System (INIS)

    Bender, Peter L

    2006-01-01

    The three spacecraft of the Laser Interferometer Space Antenna will form a nearly equilateral triangle with nominal side lengths of 5 million km. However, the arm lengths and the corner angles will vary by very roughly 1% over 5-10 years. Part of this variation is due to the nature of Kepler orbits around the Sun. But Sweetser (2006 Astrodynamics 2005, Advances in the Astronautical Sciences vol 123 (San Diego, CA: Univelt Inc.) pp 693-712) has shown recently that differential secular accelerations due to the Earth for the three spacecraft prevent the minimal variations from being preserved for more than 2 or 3 years. Based on Sweetser's results, it appears possible to cancel out the differential secular acceleration due to the Earth by applying forces to the two proof masses in each spacecraft. The applied acceleration is at most 2.1 x 10 -9 m s -2 . However, the directions of the required accelerations would have substantial components along the sides of the triangle, and thus the amplitudes of the applied forces would have to have very low noise, even at frequencies down to below 0.1 mHz

  15. Huvitavat lisa Austraaliast Eesti mäluasutustele / Anne Valmas

    Index Scriptorium Estoniae

    Valmas, Anne, 1941-2017

    2007-01-01

    Eesti Arhiiv Austraalias säilitab meie kultuurile olulist vaimuvara - trükiseid, käsikirju, fotosid, filme, mälestusesemeid. Näitusest Sydney Powerhouse Museumìs "Our new home - Meie uus kodu: Estonian-Australian Stories", kus eksponaatidena kasutati arhiivi materjale, näitusest Wollondilly kultuuripärandi keskuses

  16. Plasma heating by radio frequency in the LISA linear machine

    International Nuclear Information System (INIS)

    Cunha Raposo, C. da.

    1985-05-01

    The characteristics of an experimental apparatus to produce helium plasma by radio frequency and to study its behavior when confined by a magnetic field with mirrors is shown. The plasma was produced by a microwave source of 2.45 GHz and 800 Watts, operating in steady and pulsed state. The plasma parameters were studied as a function of an external magnetic field, for large and small resonance regions. The axial and radial magnetic fields were mapped for each region in order to verify the spatial distribution, particle orbits, and energy confinement time according to the energy balance equation. As a consequence of the influence of the radio frequency (RF) voltage in the plasma the Bohm theory of plasma prob was modified. The diagnostic was done with plane movable electrostatic probe, Hall probe, magnetic probe, diamagnetic coil and spectrography. (Author) [pt

  17. Thermal diagnostic of the optical window on board LISA Pathfinder

    International Nuclear Information System (INIS)

    Nofrarias, M; MarIn, A F GarcIa; Lobo, A; Heinzel, G; Ramos-Castro, J; Sanjuan, J; Danzmann, K

    2007-01-01

    Vacuum conditions inside the LTP gravitational reference sensor must be under 10 -5 Pa, a rather demanding requirement. The optical window (OW) is an interface which seals the vacuum enclosure and, at the same time, lets the laser beam go through for interferometric metrology with the test masses. The OW is a plane-parallel plate clamped in a titanium flange, and is considerably sensitive to thermal and stress fluctuations. It is critical for the required precision measurements, hence its temperature will be carefully monitored in flight. This paper reports on the results of a series of OW characterization laboratory runs, intended to study its response to selected thermal signals, as well as their fit to numerical models, and the meaning of the latter. We find that a single-pole ARMA transfer function provides a consistent approximation to the OW response to thermal excitations, and derive a relationship with the physical processes taking place in the OW. We also show how the system noise reduction can be accomplished by means of that transfer function

  18. FLIPPED LEARNING: PRACTICAL ASPECTS

    Directory of Open Access Journals (Sweden)

    Olena Kuzminska

    2016-03-01

    Full Text Available The article is devoted to issues of implementation of the flipped learning technology in the practice of higher education institutions. The article defines the principles of technology and a model of the educational process, it notes the need to establish an information support system. The article defines online platforms and resources; it describes recommendations for the design of electronic training courses and organization of the students in the process of implementing the proposed model, as well as tools for assessing its effectiveness. The article provides a description of flipped learning implementation scenario and formulates suggestions regarding the use of this model as a mechanism to improve the efficiency of the learning process in the ICT-rich environment of high school: use of learning management systems (LMS and personal learning environments (PLE of participants in a learning process. The article provides an example of implementation of the flipped learning model as a part of the Information Technologies course in the National University of Life and Environmental Sciences of Ukraine (NULES. The article gives examples of tasks, resources and services, results of students’ research activity, as well as an example of the personal learning network, established in the course of implementation of the flipped learning model and elements of digital student portfolios. It presents the results of the monitoring of learning activities and students’ feedback. The author describes cautions against the mass introduction of the flipped learning model without monitoring of readiness of the participants of the educational process for its implementation

  19. Learning and memory

    Directory of Open Access Journals (Sweden)

    P. A. J. Ryke

    1989-03-01

    Full Text Available Under various circumstances and in different species the outward expression of learning varies considerably, and this has led to the classification of different categories of learning. Just as there is no generally agreed on definition of learning, there is no one system of classification. Types of learning commonly recognized are: Habituation, sensitization, classical conditioning, operant conditioning, trial and error, taste aversion, latent learning, cultural learning, imprinting, insight learning, learning-set learning and instinct. The term memory must include at least two separate processes. It must involve, on the one hand, that of learning something and on the other, at some later date, recalling that thing. What lies between the learning and (he remembering must be some permanent record — a memory trace — within the brain. Memory exists in at least two forms: memory for very recent events (short-term which is relatively labile and easily disruptable; and long-term memory, which is much more stable. Not everything that gets into short-term memory becomes fixed in the long-term store; a filtering mechanism selects things that might be important and discards the rest.

  20. Approximate kernel competitive learning.

    Science.gov (United States)

    Wu, Jian-Sheng; Zheng, Wei-Shi; Lai, Jian-Huang

    2015-03-01

    Kernel competitive learning has been successfully used to achieve robust clustering. However, kernel competitive learning (KCL) is not scalable for large scale data processing, because (1) it has to calculate and store the full kernel matrix that is too large to be calculated and kept in the memory and (2) it cannot be computed in parallel. In this paper we develop a framework of approximate kernel competitive learning for processing large scale dataset. The proposed framework consists of two parts. First, it derives an approximate kernel competitive learning (AKCL), which learns kernel competitive learning in a subspace via sampling. We provide solid theoretical analysis on why the proposed approximation modelling would work for kernel competitive learning, and furthermore, we show that the computational complexity of AKCL is largely reduced. Second, we propose a pseudo-parallelled approximate kernel competitive learning (PAKCL) based on a set-based kernel competitive learning strategy, which overcomes the obstacle of using parallel programming in kernel competitive learning and significantly accelerates the approximate kernel competitive learning for large scale clustering. The empirical evaluation on publicly available datasets shows that the proposed AKCL and PAKCL can perform comparably as KCL, with a large reduction on computational cost. Also, the proposed methods achieve more effective clustering performance in terms of clustering precision against related approximate clustering approaches. Copyright © 2014 Elsevier Ltd. All rights reserved.