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Sample records for celestial reference frame

  1. Connecting VLBI and Gaia celestial reference frames

    Directory of Open Access Journals (Sweden)

    Zinovy Malkin

    2016-09-01

    Full Text Available The current state of the link problem between radio and optical celestial reference frames is considered.The main objectives of the investigations in this direction during the next few years are the preparation of a comparisonand the mutual orientation and rotation between the optical it Gaia Celestial Reference Frame (GCRFand the 3rd generation radio International Celestial Reference Frame (ICRF3, obtained from VLBI observations.Both systems, ideally, should be a realization of the ICRS (International Celestial Reference System at micro-arcsecond level accuracy.Therefore, the link accuracy between the ICRF and GCRF should be obtained with similar error level, which is not a trivial taskdue to relatively large systematic and random errors in source positions at different frequency bands.In this paper, a brief overview of recent work on the GCRF--ICRF link is presented.Additional possibilities to improve the GCRF--ICRF link accuracy are discussed.The suggestion is made to use astrometric radio sources with optical magnitude to 20$^m$ rather than to 18$^m$ as currently plannedfor the GCRF--ICRF link.In addition, the use of radio stars is also a prospective method to obtain independent and accurate orientation between the Gaia frame and the ICRF.

  2. The International Celestial Reference Frame (ICRF) and the Relationship Between Frames

    Science.gov (United States)

    Ma, Chopo

    2000-01-01

    The International Celestial Reference Frame (ICRF), a catalog of VLBI source positions, is now the basis for astrometry and geodesy. Its construction and extension/maintenance will be discussed as well as the relationship of the ICRF, ITRF, and EOP/nutation.

  3. Consistent realization of Celestial and Terrestrial Reference Frames

    Science.gov (United States)

    Kwak, Younghee; Bloßfeld, Mathis; Schmid, Ralf; Angermann, Detlef; Gerstl, Michael; Seitz, Manuela

    2018-03-01

    The Celestial Reference System (CRS) is currently realized only by Very Long Baseline Interferometry (VLBI) because it is the space geodetic technique that enables observations in that frame. In contrast, the Terrestrial Reference System (TRS) is realized by means of the combination of four space geodetic techniques: Global Navigation Satellite System (GNSS), VLBI, Satellite Laser Ranging (SLR), and Doppler Orbitography and Radiopositioning Integrated by Satellite. The Earth orientation parameters (EOP) are the link between the two types of systems, CRS and TRS. The EOP series of the International Earth Rotation and Reference Systems Service were combined of specifically selected series from various analysis centers. Other EOP series were generated by a simultaneous estimation together with the TRF while the CRF was fixed. Those computation approaches entail inherent inconsistencies between TRF, EOP, and CRF, also because the input data sets are different. A combined normal equation (NEQ) system, which consists of all the parameters, i.e., TRF, EOP, and CRF, would overcome such an inconsistency. In this paper, we simultaneously estimate TRF, EOP, and CRF from an inter-technique combined NEQ using the latest GNSS, VLBI, and SLR data (2005-2015). The results show that the selection of local ties is most critical to the TRF. The combination of pole coordinates is beneficial for the CRF, whereas the combination of Δ UT1 results in clear rotations of the estimated CRF. However, the standard deviations of the EOP and the CRF improve by the inter-technique combination which indicates the benefits of a common estimation of all parameters. It became evident that the common determination of TRF, EOP, and CRF systematically influences future ICRF computations at the level of several μas. Moreover, the CRF is influenced by up to 50 μas if the station coordinates and EOP are dominated by the satellite techniques.

  4. OPTICAL SPECTRA OF CANDIDATE INTERNATIONAL CELESTIAL REFERENCE FRAME (ICRF) FLAT-SPECTRUM RADIO SOURCES

    Energy Technology Data Exchange (ETDEWEB)

    Titov, O.; Stanford, Laura M. [Geoscience Australia, P.O. Box 378, Canberra, ACT 2601 (Australia); Johnston, Helen M.; Hunstead, Richard W. [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia); Pursimo, T. [Nordic Optical Telescope, Nordic Optical Telescope Apartado 474E-38700 Santa Cruz de La Palma, Santa Cruz de Tenerife (Spain); Jauncey, David L. [CSIRO Astronomy and Space Science, ATNF and Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Maslennikov, K. [Central Astronomical Observatory at Pulkovo, Pulkovskoye Shosse, 65/1, 196140, St. Petersburg (Russian Federation); Boldycheva, A., E-mail: oleg.titov@ga.gov.au [Ioffe Physical Technical Institute, 26 Polytekhnicheskaya, St. Petersburg, 194021 (Russian Federation)

    2013-07-01

    Continuing our program of spectroscopic observations of International Celestial Reference Frame (ICRF) sources, we present redshifts for 120 quasars and radio galaxies. Data were obtained with five telescopes: the 3.58 m European Southern Observatory New Technology Telescope, the two 8.2 m Gemini telescopes, the 2.5 m Nordic Optical Telescope (NOT), and the 6.0 m Big Azimuthal Telescope of the Special Astrophysical Observatory in Russia. The targets were selected from the International VLBI Service for Geodesy and Astrometry candidate International Celestial Reference Catalog which forms part of an observational very long baseline interferometry (VLBI) program to strengthen the celestial reference frame. We obtained spectra of the potential optical counterparts of more than 150 compact flat-spectrum radio sources, and measured redshifts of 120 emission-line objects, together with 19 BL Lac objects. These identifications add significantly to the precise radio-optical frame tie to be undertaken by Gaia, due to be launched in 2013, and to the existing data available for analyzing source proper motions over the celestial sphere. We show that the distribution of redshifts for ICRF sources is consistent with the much larger sample drawn from Faint Images of the Radio Sky at Twenty cm (FIRST) and Sloan Digital Sky Survey, implying that the ultra-compact VLBI sources are not distinguished from the overall radio-loud quasar population. In addition, we obtained NOT spectra for five radio sources from the FIRST and NRAO VLA Sky Survey catalogs, selected on the basis of their red colors, which yielded three quasars with z > 4.

  5. A Ka-Band Celestial Reference Frame with Applications to Deep Space Navigation

    Science.gov (United States)

    Jacobs, Christopher S.; Clark, J. Eric; Garcia-Miro, Cristina; Horiuchi, Shinji; Sotuela, Ioana

    2011-01-01

    The Ka-band radio spectrum is now being used for a wide variety of applications. This paper highlights the use of Ka-band as a frequency for precise deep space navigation based on a set of reference beacons provided by extragalactic quasars which emit broadband noise at Ka-band. This quasar-based celestial reference frame is constructed using X/Ka-band (8.4/32 GHz) from fifty-five 24-hour sessions with the Deep Space Network antennas in California, Australia, and Spain. We report on observations which have detected 464 sources covering the full 24 hours of Right Ascension and declinations down to -45 deg. Comparison of this X/Ka-band frame to the international standard S/X-band (2.3/8.4 GHz) ICRF2 shows wRMS agreement of approximately 200 micro-arcsec in alpha cos(delta) and approximately 300 micro-arcsec in delta. There is evidence for systematic errors at the 100 micro-arcsec level. Known errors include limited SNR, lack of instrumental phase calibration, tropospheric refraction mis-modeling, and limited southern geometry. The motivation for extending the celestial reference frame to frequencies above 8 GHz is to access more compact source morphology for improved frame stability and to support spacecraft navigation for Ka-band based NASA missions.

  6. Micro-arcsecond Celestial Reference Frames: definition and realization — Impact of the recent IAU Resolutions

    International Nuclear Information System (INIS)

    Capitaine, Nicole

    2012-01-01

    The adoption of the International Celestial Reference System (ICRS), based on Very Long Baseline Interferometry (VLBI) observations of extragalactic radiosources by the International Astronomical Union (IAU) since 1998 January 1, opened a new era for astronomy. The ICRS and the corresponding frame, the International Celestial Reference Frame (ICRF), replaced the Fundamental Catalog (FK5) based on positions and proper motions of bright stars, with the Hipparcos catalog being adopted as the primary realization of the ICRS in optical wavelengths. According to its definition, the ICRS is such that the barycentric directions of distant extragalactic objects show no global rotation with respect to these objects; this provides a quasi-inertial reference for measuring the positions and angular motions of the celestial objects. Other resolutions on reference systems were passed by the IAU in 2000 and 2006 and endorsed by the International Union of Geodesy and Geophysics (IUGG) in 2003 and 2007, respectively. These especially concern the definition and realization of the astronomical reference systems in the framework of general relativity and transformations between them. First, the IAU 2000 resolutions refined the concepts and definition of the astronomical reference systems and parameters for Earth's rotation, and adopted the IAU 2000 precession-nutation. Then, the IAU 2006 resolutions adopted a new precession model that is consistent with dynamical theories; they also addressed definition, terminology or orientation issues relative to reference systems and time scales that needed to be specified after the adoption of the IAU 2000 resolutions. An additional IUGG 2007 resolution defined the International Terrestrial Reference System (ITRS) so that it strictly complies with the IAU recommendations. Finally, the IAU 2009 resolutions adopted a new system of astronomical constants and an improved realization of the ICRF. These fundamental changes have led to significant

  7. Impact of quasar proper motions on the alignment between the International Celestial Reference Frame and the Gaia reference frame

    Science.gov (United States)

    Liu, J.-C.; Malkin, Z.; Zhu, Z.

    2018-03-01

    The International Celestial Reference Frame (ICRF) is currently realized by the very long baseline interferometry (VLBI) observations of extragalactic sources with the zero proper motion assumption, while Gaia will observe proper motions of these distant and faint objects to an accuracy of tens of microarcseconds per year. This paper investigates the difference between VLBI and Gaia quasar proper motions and it aims to understand the impact of quasar proper motions on the alignment of the ICRF and Gaia reference frame. We use the latest time series data of source coordinates from the International VLBI Service analysis centres operated at Goddard Space Flight Center (GSF2017) and Paris observatory (OPA2017), as well as the Gaia auxiliary quasar solution containing 2191 high-probability optical counterparts of the ICRF2 sources. The linear proper motions in right ascension and declination of VLBI sources are derived by least-squares fits while the proper motions for Gaia sources are simulated taking into account the acceleration of the Solar system barycentre and realistic uncertainties depending on the source brightness. The individual and global features of source proper motions in GSF2017 and OPA2017 VLBI data are found to be inconsistent, which may result from differences in VLBI observations, data reduction and analysis. A comparison of the VLBI and Gaia proper motions shows that the accuracies of the components of rotation and glide between the two systems are 2-4 μas yr- 1 based on about 600 common sources. For the future alignment of the ICRF and Gaia reference frames at different wavelengths, the proper motions of quasars must necessarily be considered.

  8. Selecting Sources that Define a Stable Celestial Reference Frame with the Allan Variance

    Science.gov (United States)

    Le Bail, Karine; Gordon, David; Ma, Chopo

    2016-12-01

    The ICRF2 was adopted by the IAU in 2009 and was based on the positions of 3,414 radio sources determined by VLBI. Discussions on the next realization of the ICRF (ICRF3) have been underway within the IAU and IVS since 2012. VLBI has made significant advances since ICRF2. From the latest GSFC solution, we extract a set of sources that defines a stable celestial reference frame, as shown by Feissel-Vernier 2003 te{Feissel-Vernier2003} using tools such as the Allan variance and the drift of the position time series. This method also allows us to highlight a set of the least stable sources that may need special handling.

  9. THE CELESTIAL REFERENCE FRAME AT 24 AND 43 GHz. II. IMAGING

    International Nuclear Information System (INIS)

    Charlot, P.; Boboltz, D. A.; Fey, A. L.; Fomalont, E. B.; Geldzahler, B. J.; Gordon, D.; Jacobs, C. S.; Lanyi, G. E.; Naudet, C. J.; Zhang, L. D.; Ma, C.; Romney, J. D.; Sovers, O. J.

    2010-01-01

    We have measured the submilliarcsecond structure of 274 extragalactic sources at 24 and 43 GHz in order to assess their astrometric suitability for use in a high-frequency celestial reference frame (CRF). Ten sessions of observations with the Very Long Baseline Array have been conducted over the course of ∼5 years, with a total of 1339 images produced for the 274 sources. There are several quantities that can be used to characterize the impact of intrinsic source structure on astrometric observations including the source flux density, the flux density variability, the source structure index, the source compactness, and the compactness variability. A detailed analysis of these imaging quantities shows that (1) our selection of compact sources from 8.4 GHz catalogs yielded sources with flux densities, averaged over the sessions in which each source was observed, of about 1 Jy at both 24 and 43 GHz, (2) on average the source flux densities at 24 GHz varied by 20%-25% relative to their mean values, with variations in the session-to-session flux density scale being less than 10%, (3) sources were found to be more compact with less intrinsic structure at higher frequencies, and (4) variations of the core radio emission relative to the total flux density of the source are less than 8% on average at 24 GHz. We conclude that the reduction in the effects due to source structure gained by observing at higher frequencies will result in an improved CRF and a pool of high-quality fiducial reference points for use in spacecraft navigation over the next decade.

  10. The ICRF-3: Status, Plans, and Multi-wavelength Progress on the next generation Celestial Reference Frame.

    Science.gov (United States)

    Jacobs, Christopher

    2015-08-01

    ICRF-3 seeks to improve upon the highly successful ICRF-2. Our goals are to improve the precision, spatial and frequency coverage relative to the ICRF-2 by 2018. This date is driven by the desire to create radio frames that are ready for comparison with the Gaia optical frame.Several specific actions are underway. A collaboration to improve at S/X-band precision of the Very Long Baseline Array (VLBA) Calibrator Survey's ~2200 sources, which are typically 5 times less precise than the rest of the ICRF-2, is bearing fruit and is projected to yield a factor of 3 improvement in precision. S/X-band southern hemisphere precision improvements are underway with observations using southern antennas such as the AuScope, Warkworth, and HartRAO, South Africa.We also seek to improve radio frequency coverage with X/Ka-band and K-band work. An X/Ka frame of 660 sources now has full sky coverage from the addition of a 2nd southern station in Argentina which is strengthening the southern hemisphere in general. The X/Ka-band frame's precision is now comparable to the ICRF-2 for the 530 sources in common. A K-band collaboration has formed with similar coverage and southern precision goals. By the time of this meeting, we expect K-band to complete full sky coverage with south polar cap observations and to improve spatial density north of -30 deg declination with VLBA observations.On the analysis front, special attention is being given to combination techniques both of Very Long Baseline Interferometry (VLBI) frames and of multiple data types. Consistency of the Celestial Reference Frame (CRF) with the Terrestrial Reference Frame (TRF) and Earth Oreintation Parameters (EOP) is another area of concern. Comparison of celestial frame solutions from various groups is underway in order to identify and correct systematic errors. We will discuss evidence emerging for 100 µas zonal errors in the ICRF2 in the declination range from 0 to -30 deg.Finally, work is underway to identify and

  11. Variability of extragalactic sources: its contribution to the link between ICRF and the future Gaia Celestial Reference Frame

    Science.gov (United States)

    Taris, F.; Damljanovic, G.; Andrei, A.; Souchay, J.; Klotz, A.; Vachier, F.

    2018-03-01

    Context. The first release of the Gaia catalog is available since 14 September 2016. It is a first step in the realization of the future Gaia reference frame. This reference frame will be materialized by the optical positions of the sources and will be compared with and linked to the International Celestial Reference Frame, materialized by the radio position of extragalactic sources. Aim. As in the radio domain, it can be reasonably postulated that quasar optical flux variations can alert us to potential changes in the source structure. These changes could have important implications for the position of the target photocenters (together with the evolution in time of these centers) and in parallel have consequences for the link of the reference systems. Methods: A set of nine optical telescopes was used to monitor the magnitude variations, often at the same time as Gaia, thanks to the Gaia Observation Forecast Tool. The Allan variances, which are statistical tools widely used in the atomic time and frequency community, are introduced. Results: This work describes the magnitude variations of 47 targets that are suitable for the link between reference systems. We also report on some implications for the Gaia catalog. For 95% of the observed targets, new information about their variability is reported. In the case of some targets that are well observed by the TAROT telescopes, the Allan time variance shows that the longest averaging period of the magnitudes is in the range 20-70 d. The observation period by Gaia for a single target largely exceeds these values, which might be a problem when the magnitude variations exhibit flicker or random walk noises. Preliminary computations show that if the coordinates of the targets studied in this paper were affected by a white-phase noise with a formal uncertainty of about 1 mas (due to astrophysical processes that are put in evidence by the magnitude variations of the sources), it would affect the precision of the link at the

  12. A two-level approach to VLBI terrestrial and celestial reference frames using both least-squares adjustment and Kalman filter algorithms

    Science.gov (United States)

    Soja, B.; Krasna, H.; Boehm, J.; Gross, R. S.; Abbondanza, C.; Chin, T. M.; Heflin, M. B.; Parker, J. W.; Wu, X.

    2017-12-01

    The most recent realizations of the ITRS include several innovations, two of which are especially relevant to this study. On the one hand, the IERS ITRS combination center at DGFI-TUM introduced a two-level approach with DTRF2014, consisting of a classical deterministic frame based on normal equations and an optional coordinate time series of non-tidal displacements calculated from geophysical loading models. On the other hand, the JTRF2014 by the combination center at JPL is a time series representation of the ITRF determined by Kalman filtering. Both the JTRF2014 and the second level of the DTRF2014 are thus able to take into account short-term variations in the station coordinates. In this study, based on VLBI data, we combine these two approaches, applying them to the determination of both terrestrial and celestial reference frames. Our product has two levels like DTRF2014, with the second level being a Kalman filter solution like JTRF2014. First, we compute a classical TRF and CRF in a global least-squares adjustment by stacking normal equations from 5446 VLBI sessions between 1979 and 2016 using the Vienna VLBI and Satellite Software VieVS (solution level 1). Next, we obtain coordinate residuals from the global adjustment by applying the level-1 TRF and CRF in the single-session analysis and estimating coordinate offsets. These residuals are fed into a Kalman filter and smoother, taking into account the stochastic properties of the individual stations and radio sources. The resulting coordinate time series (solution level 2) serve as an additional layer representing irregular variations not considered in the first level of our approach. Both levels of our solution are implemented in VieVS in order to test their individual and combined performance regarding the repeatabilities of estimated baseline lengths, EOP, and radio source coordinates.

  13. Global Vertical Reference Frame

    Czech Academy of Sciences Publication Activity Database

    Burša, Milan; Kenyon, S.; Kouba, J.; Šíma, Zdislav; Vatrt, V.; Vojtíšková, M.

    2004-01-01

    Roč. 33, - (2004), s. 404-407 ISSN 1436-3445 Institutional research plan: CEZ:AV0Z1003909 Keywords : geopotential WO * vertical systems * global vertical frame Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  14. Global Vertical Reference Frame

    Czech Academy of Sciences Publication Activity Database

    Burša, Milan; Kenyon, S.; Kouba, J.; Šíma, Zdislav; Vatrt, V.; Vojtíšková, M.

    -, č. 5 (2009), s. 53-63 ISSN 1801-8483 R&D Projects: GA ČR GA205/08/0328 Institutional research plan: CEZ:AV0Z10030501 Keywords : sea surface topography * satellite altimetry * vertical frames Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  15. Reference frame for Product Configuration

    DEFF Research Database (Denmark)

    Ladeby, Klaes Rohde; Oddsson, Gudmundur Valur

    2011-01-01

    This paper presents a reference frame for configuration. The reference frame is established by review of existing literature, and consequently it is a theoretical frame of reference. The review of literature shows a deterioration of the understanding of configuration. Most recent literature reports...

  16. Mechanical Energy Change in Inertial Reference Frames

    Science.gov (United States)

    Ghanbari, Saeed

    2016-01-01

    The mechanical energy change of a system in an inertial frame of reference equals work done by the total nonconservative force in the same frame. This relation is covariant under the Galilean transformations from inertial frame S to S', where S' moves with constant velocity relative to S. In the presence of nonconservative forces, such as normal…

  17. A global vertical reference frame based on four regional vertical datums

    Czech Academy of Sciences Publication Activity Database

    Burša, Milan; Kenyon, S.; Kouba, J.; Šíma, Zdislav; Vatrt, V.; Vojtíšková, M.

    2004-01-01

    Roč. 48, č. 3 (2004), s. 493-502 ISSN 0039-3169 Institutional research plan: CEZ:AV0Z1003909 Keywords : geopotentinal * local vertical datums * global vertical reference frame Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.447, year: 2004

  18. Quantum communication, reference frames, and gauge theory

    International Nuclear Information System (INIS)

    Enk, S. J. van

    2006-01-01

    We consider quantum communication in the case that the communicating parties not only do not share a reference frame but use imperfect quantum communication channels, in that each channel applies some fixed but unknown unitary rotation to each qubit. We discuss similarities and differences between reference frames within that quantum communication model and gauge fields in gauge theory. We generalize the concept of refbits and analyze various quantum communication protocols within the communication model

  19. Physics of Non-Inertial Reference Frames

    International Nuclear Information System (INIS)

    Kamalov, Timur F.

    2010-01-01

    Physics of non-inertial reference frames is a generalizing of Newton's laws to any reference frames. It is the system of general axioms for classical and quantum mechanics. The first, Kinematics Principle reads: the kinematic state of a body free of forces conserves and equal in absolute value to an invariant of the observer's reference frame. The second, Dynamics Principle extended Newton's second law to non-inertial reference frames and also contains additional variables there are higher derivatives of coordinates. Dynamics Principle reads: a force induces a change in the kinematic state of the body and is proportional to the rate of its change. It is mean that if the kinematic invariant of the reference frame is n-th derivative with respect the time, then the dynamics of a body being affected by the force F is described by the 2n-th differential equation. The third, Statics Principle reads: the sum of all forces acting a body at rest is equal to zero.

  20. Frames of reference in spatial language acquisition.

    Science.gov (United States)

    Shusterman, Anna; Li, Peggy

    2016-08-01

    Languages differ in how they encode spatial frames of reference. It is unknown how children acquire the particular frame-of-reference terms in their language (e.g., left/right, north/south). The present paper uses a word-learning paradigm to investigate 4-year-old English-speaking children's acquisition of such terms. In Part I, with five experiments, we contrasted children's acquisition of novel word pairs meaning left-right and north-south to examine their initial hypotheses and the relative ease of learning the meanings of these terms. Children interpreted ambiguous spatial terms as having environment-based meanings akin to north and south, and they readily learned and generalized north-south meanings. These studies provide the first direct evidence that children invoke geocentric representations in spatial language acquisition. However, the studies leave unanswered how children ultimately acquire "left" and "right." In Part II, with three more experiments, we investigated why children struggle to master body-based frame-of-reference words. Children successfully learned "left" and "right" when the novel words were systematically introduced on their own bodies and extended these words to novel (intrinsic and relative) uses; however, they had difficulty learning to talk about the left and right sides of a doll. This difficulty was paralleled in identifying the left and right sides of the doll in a non-linguistic memory task. In contrast, children had no difficulties learning to label the front and back sides of a doll. These studies begin to paint a detailed account of the acquisition of spatial terms in English, and provide insights into the origins of diverse spatial reference frames in the world's languages. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  1. Time Contraction Within Lightweight Reference Frames

    Science.gov (United States)

    Savi, Matheus F.; Angelo, Renato M.

    2017-06-01

    The special theory of relativity teaches us that, although distinct inertial frames perceive the same dynamical laws, space and time intervals differ in value. We revisit the problem of time contraction using the paradigmatic model of a fast-moving laboratory within which a photon is emitted and posteriorly absorbed. In our model, however, the laboratory is composed of two independent parallel plates, each of which allowed to be sufficiently light so as to get kickbacks upon emission and absorption of light. We show that the lightness of the laboratory accentuates the time contraction. We also discuss how the photon frequency shifts upon reflection in a light moving mirror. Although often imperceptible, these effects will inevitably exist whenever realistic finite-mass bodies are involved. More fundamentally, they should necessarily permeate any eventual approach to the problem of relativistic quantum frames of reference.

  2. Quantum mechanics with respect to different reference frames

    International Nuclear Information System (INIS)

    Mangiarotti, L.; Sardanashvily, G.

    2007-01-01

    Geometric (Schroedinger) quantization of nonrelativistic mechanics with respect to different reference frames is considered. In classical nonrelativistic mechanics, a reference frame is represented by a connection on a configuration space fibered over a time axis R. Under quantization, it yields a connection on the quantum algebra of Schroedinger operators. The operators of energy with respect to different reference frames are examined

  3. Entanglement detection with bounded reference frames

    International Nuclear Information System (INIS)

    Costa, Fabio; Brukner, Caslav; Harrigan, Nicholas; Rudolph, Terry

    2009-01-01

    Quantum experiments usually assume the existence of perfect, classical reference frames (RFs), which allow for the specification of measurement settings (e.g. orientation of the Stern-Gerlach magnet in spin measurements) with arbitrary precision. If the RFs are 'bounded' (i.e. quantum systems themselves, having a finite number of degrees of freedom), only limited precision can be attained. Using spin coherent states as bounded RFs, we have found the minimum size needed for them to violate local realism for entangled spin systems. For composite systems of spin 1/2 particles, RFs of very small size are sufficient for the violation; however, to see this violation for macroscopic entangled spins, the size of the RF must be at least quadratically larger than that of the spins. The unavailability of such RFs gives a possible explanation for the non-observance of violation of local realism in everyday experience.

  4. Spatial priming in ecologically relevant reference frames.

    Science.gov (United States)

    Tower-Richardi, Sarah M; Leber, Andrew B; Golomb, Julie D

    2016-01-01

    In recent years, researchers have observed many phenomena demonstrating how the visual system exploits spatial regularities in the environment in order to benefit behavior. In this paper, we question whether spatial priming can be considered one such phenomenon. Spatial priming is defined as a response time facilitation to a visual search target when its spatial position has been repeated in recent trials (Maljkovic & Nakayama, 1996, Perception & Psychophysics, 58, 977-991). Does this priming serve a behaviorally adaptive role or is it merely a byproduct of ongoing visual processing? Critically, an adaptive priming mechanism must actively transform visual inputs from native retinotopic (eye-centered) coordinates into ecologically relevant coordinates, e.g., spatiotopic (world-centered) and/or object-centered. In Experiment 1, we tested this hypothesis by having participants move their eyes between trials, which dissociated retinotopic and spatiotopic frames of reference. Results showed only weak retinotopic priming, but robust spatiotopic priming. The second experiment again had participants move their eyes between trials but also manipulated the placement of a grouped array of display objects from trial to trial. This allowed us to measure not just retinotopic and spatiotopic priming, but object-centered priming as well. Results from this experiment did not yield retinotopic priming but showed robust spatiotopic and object-centered priming. These findings demonstrate that spatial priming operates within ecologically relevant coordinate systems, and the findings support the notion that spatial priming serves an adaptive role in human behavior.

  5. Post-Newtonian reference frames for advanced theory of the lunar motion and for a new generation of Lunar laser ranging

    International Nuclear Information System (INIS)

    Xie, Yi.; Kopeikin, S.

    2010-01-01

    We overview a set of post-Newtonian reference frames for a comprehensive study of the orbital dynamics and rotational motion of Moon and Earth by means of lunar laser ranging. We employ a scalar-tensor theory of gravity depending on two post-Newtonian parameters, and utilize the relativistic resolutions on reference frames adopted by the International Astronomical Union in 2000. We assume that the solar system is isolated and space-time is asymptotically flat at infinity. The primary reference frame covers the entire space-time, has its origin at the solar-system barycenter and spatial axes stretching up to infinity. The solar-system barycenter frame is not rotating with respect to a set of distant quasars that are forming the International Celestial Reference Frame. The secondary reference frame has its origin at the Earth-Moon barycenter. The Earth-Moon barycenter frame is locally-inertial and is not rotating dynamically in the sense that equation of motion of a test particle moving with respect to the Earth-Moon barycenter frame, does not contain the Coriolis and centripetal forces. Two other local frames-geocentric and seleno centric-have their origins at the center of mass of Earth and Moon respectively and do not rotate dynamically. Each local frame is subject to the geodetic precession both with respect to other local frames and with respect to the International Celestial Reference Frame because of their relative motion with respect to each other. Theoretical advantage of the dynamically non-rotating local frames is in a more simple mathematical description. Each local frame can be aligned with the axes of International Celestial Reference Frame after applying the matrix of the relativistic precession. The set of one global and three local frames is introduced in order to fully decouple the relative motion of Moon with respect to Earth from the orbital motion of the Earth-Moon barycenter as well as to connect the coordinate description of the lunar motion

  6. Measuring the quality of a quantum reference frame: The relative entropy of frameness

    International Nuclear Information System (INIS)

    Gour, Gilad; Marvian, Iman; Spekkens, Robert W.

    2009-01-01

    In the absence of a reference frame for transformations associated with group G, any quantum state that is noninvariant under the action of G may serve as a token of the missing reference frame. We here present a measure of the quality of such a token: the relative entropy of frameness. This is defined as the relative entropy distance between the state of interest and the nearest G-invariant state. Unlike the relative entropy of entanglement, this quantity is straightforward to calculate, and we find it to be precisely equal to the G-asymmetry, a measure of frameness introduced by Vaccaro et al. It is shown to provide an upper bound on the mutual information between the group element encoded into the token and the group element that may be extracted from it by measurement. In this sense, it quantifies the extent to which the token successfully simulates a full reference frame. We also show that despite a suggestive analogy from entanglement theory, the regularized relative entropy of frameness is zero and therefore does not quantify the rate of interconversion between the token and some standard form of quantum reference frame. Finally, we show how these investigations yield an approach to bounding the relative entropy of entanglement.

  7. Disambiguation of Mental Rotation by Spatial Frames of Reference

    Directory of Open Access Journals (Sweden)

    Nobuhiko Asakura

    2011-06-01

    Full Text Available Previous research has shown that our ability to imagine object rotations is limited and associated with spatial reference frames; performance is poor unless the axis of rotation is aligned with the object-intrinsic frame or with the environmental frame. Here, we report an active effect of these reference frames on the process of mental rotation: they can disambiguate object rotations when the axis of rotation is ambiguous. Using novel mental rotation stimuli, in which the rotational axes between pairs of objects can be defined with respect to multiple frames of reference, we demonstrate that the vertical axis is preferentially used for imagined object rotations over the object-intrinsic axis for an efficient minimum rotation. In contrast, the object-intrinsic axis can play a decisive role when the vertical axis is absent as a way of resolving the ambiguity of rotational motion. When interpreted in conjunction with recent advances in the Bayesian framework for motion perception, our results suggest that these spatial frames of reference are incorporated into an internal model of object rotations, thereby shaping our ability to imagine the transformation of an object's spatial structure.

  8. Perception of space by multiple intrinsic frames of reference.

    Directory of Open Access Journals (Sweden)

    Yanlong Sun

    Full Text Available It has been documented that when memorizing a physical space, the person's mental representation of that space is biased with distortion and segmentation. Two experiments reported here suggest that distortion and segmentation arise due to a hierarchical organization of the spatial representation. The spatial relations associated with salient landmarks are more strongly encoded and easier to recall than those associated with non-salient landmarks. In the presence of multiple salient landmarks, multiple intrinsic frames of reference are formed and spatial relations are anchored to each individual frame of reference. Multiple such representations may co-exist and interactively determine a person's spatial performance.

  9. The resource theory of quantum reference frames: manipulations and monotones

    International Nuclear Information System (INIS)

    Gour, Gilad; Spekkens, Robert W

    2008-01-01

    Every restriction on quantum operations defines a resource theory, determining how quantum states that cannot be prepared under the restriction may be manipulated and used to circumvent the restriction. A superselection rule (SSR) is a restriction that arises through the lack of a classical reference frame and the states that circumvent it (the resource) are quantum reference frames. We consider the resource theories that arise from three types of SSRs, associated respectively with lacking: (i) a phase reference, (ii) a frame for chirality, and (iii) a frame for spatial orientation. Focusing on pure unipartite quantum states (and in some cases restricting our attention even further to subsets of these), we explore single-copy and asymptotic manipulations. In particular, we identify the necessary and sufficient conditions for a deterministic transformation between two resource states to be possible and, when these conditions are not met, the maximum probability with which the transformation can be achieved. We also determine when a particular transformation can be achieved reversibly in the limit of arbitrarily many copies and find the maximum rate of conversion. A comparison of the three resource theories demonstrates that the extent to which resources can be interconverted decreases as the strength of the restriction increases. Along the way, we introduce several measures of frameness and prove that these are monotonically non-increasing under various classes of operations that are permitted by the SSR

  10. Symmetry, Reference Frames, and Relational Quantities in Quantum Mechanics

    Science.gov (United States)

    Loveridge, Leon; Miyadera, Takayuki; Busch, Paul

    2018-02-01

    We propose that observables in quantum theory are properly understood as representatives of symmetry-invariant quantities relating one system to another, the latter to be called a reference system. We provide a rigorous mathematical language to introduce and study quantum reference systems, showing that the orthodox "absolute" quantities are good representatives of observable relative quantities if the reference state is suitably localised. We use this relational formalism to critique the literature on the relationship between reference frames and superselection rules, settling a long-standing debate on the subject.

  11. The equations of relative motion in the orbital reference frame

    Science.gov (United States)

    Casotto, Stefano

    2016-03-01

    The analysis of relative motion of two spacecraft in Earth-bound orbits is usually carried out on the basis of simplifying assumptions. In particular, the reference spacecraft is assumed to follow a circular orbit, in which case the equations of relative motion are governed by the well-known Hill-Clohessy-Wiltshire equations. Circular motion is not, however, a solution when the Earth's flattening is accounted for, except for equatorial orbits, where in any case the acceleration term is not Newtonian. Several attempts have been made to account for the J_2 effects, either by ingeniously taking advantage of their differential effects, or by cleverly introducing ad-hoc terms in the equations of motion on the basis of geometrical analysis of the J_2 perturbing effects. Analysis of relative motion about an unperturbed elliptical orbit is the next step in complexity. Relative motion about a J_2-perturbed elliptic reference trajectory is clearly a challenging problem, which has received little attention. All these problems are based on either the Hill-Clohessy-Wiltshire equations for circular reference motion, or the de Vries/Tschauner-Hempel equations for elliptical reference motion, which are both approximate versions of the exact equations of relative motion. The main difference between the exact and approximate forms of these equations consists in the expression for the angular velocity and the angular acceleration of the rotating reference frame with respect to an inertial reference frame. The rotating reference frame is invariably taken as the local orbital frame, i.e., the RTN frame generated by the radial, the transverse, and the normal directions along the primary spacecraft orbit. Some authors have tried to account for the non-constant nature of the angular velocity vector, but have limited their correction to a mean motion value consistent with the J_2 perturbation terms. However, the angular velocity vector is also affected in direction, which causes precession

  12. Cross-Sensory Transfer of Reference Frames in Spatial Memory

    Science.gov (United States)

    Kelly, Jonathan W.; Avraamides, Marios N.

    2011-01-01

    Two experiments investigated whether visual cues influence spatial reference frame selection for locations learned through touch. Participants experienced visual cues emphasizing specific environmental axes and later learned objects through touch. Visual cues were manipulated and haptic learning conditions were held constant. Imagined perspective…

  13. Developing a Frame of Reference for understanding configuration systems

    DEFF Research Database (Denmark)

    Ladeby, Klaes Rohde; Edwards, Kasper

    2008-01-01

    This paper uses the theory of technical systems to develop a frame of reference of product configuration systems. Following a definition of the configuration task, product model and product configuration system the theory of technical systems are presented. Configuration systems are then related...

  14. Celestial Treasury

    Science.gov (United States)

    Lachièze-Rey, Marc; Luminet, Jean-Pierre

    2001-07-01

    Throughout history, the mysterious dark skies have inspired our imaginations in countless ways, influencing our endeavors in science and philosophy, religion, literature, and art. Filled with 380 full-color illustrations, Celestial Treasury shows the influence of astronomical theories and the richness of illustrations in Western civilization through the ages. The authors explore the evolution of our understanding of astronomy and weave together ancient and modern theories in a fascinating narrative. They incorporate a wealth of detail from Greek verse, medieval manuscripts and Victorian poetry with contemporary spacecraft photographs and computer-generated star charts. Celestial Treasury is more than a beautiful book: it answers a variety of questions that have intrigued scientists and laymen for centuries. -- How did philosophers and scientists try to explain the order that governs celestial motion? -- How did geometers and artists measure and map the skies? -- How many different answers have been proposed for the most fundamental of all questions: When and how did Earth come about? -- Who inhabits the heavens--gods, angels or extraterrestrials? No other book recounts humankind's fascination with the heavens as compellingly as Celestial Treasury. Marc Lachièze-Rey is a director of research at the Centre National pour la Récherche Scientifique and astrophysicist at the Centre d'Etudes de Saclay. He is the author of The Cosmic Background Radiation (Cambridge, 1999), and and The Quest for Unity, (Oxford, 1999 ), as well as many books in French. Jean-Pierre Luminet is a research director of the Centre National pour la Rechérche Scientifique, based at the Paris-Meudon observatory. He is the author of Black Holes, (Cambridge 1992), as well as science documentaries for television.

  15. Rigorous Combination of GNSS and VLBI: How it Improves Earth Orientation and Reference Frames

    Science.gov (United States)

    Lambert, S. B.; Richard, J. Y.; Bizouard, C.; Becker, O.

    2017-12-01

    Current reference series (C04) of the International Earth Rotation and Reference Systems Service (IERS) are produced by a weighted combination of Earth orientation parameters (EOP) time series built up by combination centers of each technique (VLBI, GNSS, Laser ranging, DORIS). In the future, we plan to derive EOP from a rigorous combination of the normal equation systems of the four techniques.We present here the results of a rigorous combination of VLBI and GNSS pre-reduced, constraint-free, normal equations with the DYNAMO geodetic analysis software package developed and maintained by the French GRGS (Groupe de Recherche en GeÌodeÌsie Spatiale). The used normal equations are those produced separately by the IVS and IGS combination centers to which we apply our own minimal constraints.We address the usefulness of such a method with respect to the classical, a posteriori, combination method, and we show whether EOP determinations are improved.Especially, we implement external validations of the EOP series based on comparison with geophysical excitation and examination of the covariance matrices. Finally, we address the potential of the technique for the next generation celestial reference frames, which are currently determined by VLBI only.

  16. Frames of Reference and Antecedentless Anaphora in Spanish Conversation.

    Science.gov (United States)

    Blackwell, Sarah E

    2018-04-01

    This study examines native Spanish speakers' use of anaphoric pronouns and null subjects in conversational discourse in the absence of coreferential antecedents. It also considers the adequacy of Gundel et al.'s proposal  (Language 69(2):274-307, 1993) that the cognitive status "in focus" corresponds with speakers' use of minimal referring expressions (i.e., unstressed pronouns and zeros). Analysis of naturally occurring Spanish conversation shows how the felicitous use and interpretation of non-canonical (antecedentless) anaphoric pronouns and null subjects are possible due to the activation of underlying cognitive frames that are shared by the interlocutors. Furthermore, the speaker's mention of a referent, dubbed a "neighborhood antecedent" by Langacker (Conceptual grouping and pronominal anaphora, in: Fox (ed) Studies in anaphora, Cambridge University Press, Cambridge, 1996), and the information "filled in" over the course of the conversation on account of the activation of relevant cognitive frames, both license and disambiguate the non-canonical anaphoric relations.

  17. External Aerodynamics Simulations in a Rotating Frame of Reference

    Directory of Open Access Journals (Sweden)

    Filomena Cariglino

    2014-01-01

    Full Text Available This paper presents the development of a tool integrated in the UNS3D code, proprietary of Alenia Aermacchi, for the simulation of external aerodynamic flow in a rotating reference frame, with the main objective of predicting propeller-aircraft integration effects. The equations in a rotating frame of reference have been formulated in terms of the absolute velocity components; in this way, the artificial dissipation needed for convergence is lessened, as the Coriolis source term is only introduced in the momentum equation. An Explicit Algebraic Reynolds Stress turbulence model is used. The first assessment of effectiveness of this method is made computing stability derivatives of a NACA 0012 airfoil. Finally, steady Navier-Stokes and Euler simulations of a four-blade single-rotating propeller are presented, demonstrating the efficiency of the chosen approach in terms of computational cost.

  18. Frames of reference in mobile augmented reality displays.

    Science.gov (United States)

    Mou, Weimin; Biocca, Frank; Owen, Charles B; Tang, Arthur; Xiao, Fan; Lim, Lynette

    2004-12-01

    In 3 experiments, the authors investigated spatial updating in augmented reality environments. Participants learned locations of virtual objects on the physical floor. They were turned to appropriate facing directions while blindfolded before making pointing judgments (e.g., "Imagine you are facing X. Point to Y"). Experiments manipulated the angular difference between the learning heading and the imagined heading and between the actual heading and the imagined heading. The effect of actual-imagined on pointing latency was observed for naive users but not for users with brief training or instructions concerning the fact that objects can move with body movements. The results indicated that naive users used an environment-stabilized reference frame to access information arrays, but with experience and instruction the nature of the representation changed from an environment stabilized to a body stabilized reference frame. copyright (c) 2004 APA, all rights reserved.

  19. Selection of spatial reference frames depends on task's demands

    Directory of Open Access Journals (Sweden)

    Greeshma Sharma

    2016-12-01

    Full Text Available Spatial reference frames (SRF are the means of representing spatial relations or locations either in an egocentric coordinate system (centred on navigator or in an allocentric coordinate system (Centred on object. It is necessary to understand when and how spatial representation switches between allocentric and egocentric reference frames in context to spatial tasks. The objective of this study was to explore if the elementary spatial representation does exist, whether it would remain consistent or change under the influence of a task's demand. Also, we explored how the SRF would assist if the environment is enriched with landmarks, having multiple routes for wayfinding. The results showed that the switching of SRF depends not only on the default representation but also on a task's demand. They also demonstrated that participants who were using allocentric representation performed better in the presence of landmarks.

  20. Dissociating contributions of head and torso to spatial reference frames

    DEFF Research Database (Denmark)

    Alsmith, Adrian J T; Ferrè, Elisa R; Longo, Matthew R.

    2017-01-01

    contribution of each part to spatial judgments. Both the head and the torso contributed to judgements, though with greater contributions from the torso. A second experiment manipulating visual contrast of the torso showed that this does not reflect low-level differences in visual salience between body parts....... Our results demonstrate that spatial perspective-taking relies on a weighted combination of reference frames centred on different parts of the body....

  1. Interaction between Reference Frames, A Concern in Embedded Training?

    Science.gov (United States)

    2009-10-01

    question the role of the adjustment mode. The classical SV setting, by mean of a rod controlled by a remote system was compared to a visuo- kinesthetic ...strict instrument flying rules. Sensory illusion may be generated by a short time movement (e.g. head movement during a turn) or constructed along...by a laser beam (=532 nm (green), ɛ mW). Mirrors movements and laser on-off were noiseless to the subject. Interaction between Reference Frames

  2. Representing Spatial Layout According to Intrinsic Frames of Reference.

    Science.gov (United States)

    Xie, Chaoxiang; Li, Shiyi; Tao, Weidong; Wei, Yiping; Sun, Hong-Jin

    2017-01-01

    Mou and McNamara have suggested that object locations are represented according to intrinsic reference frames. In three experiments, we investigated the limitations of intrinsic reference frames as a mean to represent object locations in spatial memory. Participants learned the locations of seven or eight common objects in a rectangular room and then made judgments of relative direction based on their memory of the layout. The results of all experiments showed that when all objects were positioned regularly, judgments of relative direction were faster or more accurate for novel headings that were aligned with the primary intrinsic structure than for other novel headings; however, when one irregularly positioned object was added to the layout, this advantage was eliminated. The experiments further indicated that with a single view at study, participants could represent the layout from either an egocentric orientation or a different orientation, according to experimental instructions. Together, these results suggest that environmental reference frames and intrinsic axes can influence performance for novel headings, but their role in spatial memory depends on egocentric experience, layout regularity, and instructions.

  3. Optical counterpart positions of extragalactic radio sources and connecting optical and radio reference frames

    Science.gov (United States)

    Aslan, Z.; Gumerov, R.; Jin, W.; Khamitov, I.; Maigurova, N.; Pinigin, G.; Tang, Z.; Wang, S.

    2010-01-01

    We discuss the results of an investigation of astrometric positions of extragalactic radio sources from a list for the International Celestial Reference Frame. About 300 fields around extragalactic radio sources were observed during the years 2000-2003. The observations were performed mainly using two telescopes equipped with CCD cameras at TUG, Turkey (Russian-Turkish Telescope - RTT150) and at YAO (1 m telescope), (Kunming, China). The mean accuracies of the measured positions are 38 mas in right ascension and 35 mas in declination. A comparison between the measured optical positions determined using the UCAC2 catalog and the radio positions from the current ICRF shows that the overall optical-minus- radio offsets are -4 and +15 mas for right ascension and declination, respectively. The formal internal errors of these mean offsets are 4 mas. The results of optical positions with respect to the reference catalogue 2MASS are also given. A search for a relation between optical and radio reference frames indicates that the orientation angles are near zero within their accuracy of about 5 mas. The link accuracy becomes 3 mas when our observations are combined with other studies. Tables 2 and 3 giving the positions are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/510/A10Present address: İstanbul Kültür University, Ataköy Yerleşkesi, 34156 Istanbul, Turkey

  4. Facilitation and interference in spatial and body reference frames.

    Science.gov (United States)

    Wiggett, Alison J; Downing, Paul E; Tipper, Steven P

    2013-03-01

    The observation of someone else's action facilitates similar actions in the observer. Such priming effects can be driven by alignment between the observer and the observed in body-centred or spatial coordinates (or both). The separate and joint contributions of these sources of priming remain to be fully characterised. Here, we compare spatial and body priming effects across the whole body "space", by using hand and foot responses. This allows a clearer separation of body priming from spatial priming than available from previous studies. In addition, we demonstrate two further features of these action priming effects. First, there are general interference and facilitation effects when the layout of viewed displays matches the participant's body (e.g. hand above the foot). These effects have not been considered in previous studies. Second, by taking these layout effects into account, we identify the facilitation and interference components of spatial and body priming effects. Both types of priming effect are observed, and facilitation and interference effects are only observed when both body and spatial frames of reference are working in the same direction. These findings show that in action perception, the behaviours of others are processed simultaneously in multiple frames of reference that have complex, interacting effects--both facilitating and interfering--on the motor system of the observer.

  5. Methods of celestial mechanics

    CERN Document Server

    Brouwer, Dirk

    2013-01-01

    Methods of Celestial Mechanics provides a comprehensive background of celestial mechanics for practical applications. Celestial mechanics is the branch of astronomy that is devoted to the motions of celestial bodies. This book is composed of 17 chapters, and begins with the concept of elliptic motion and its expansion. The subsequent chapters are devoted to other aspects of celestial mechanics, including gravity, numerical integration of orbit, stellar aberration, lunar theory, and celestial coordinates. Considerable chapters explore the principles and application of various mathematical metho

  6. Choosing Frames of Reference: Perspective-Taking in a 2D and 3D Navigational Task

    National Research Council Canada - National Science Library

    Mintz, Farilee E; Trafton, J. G; Marsh, Elaine; Perzanowski, Dennis

    2004-01-01

    ... (3D-Camera) in which depth cues were manipulated. Our results show people adopt an egocentric frame of reference when depth cues are salient and an exocentric reference frame when depth cues are absent...

  7. Combined astrometric catalogue EOC-3 An improved reference frame for long-term Earth rotation studies

    Czech Academy of Sciences Publication Activity Database

    Vondrák, Jan; Štefka, Vojtěch

    2007-01-01

    Roč. 463, č. 2 (2007), s. 783-788 ISSN 0004-6361 R&D Projects: GA MŠk(CZ) LC506 Institutional research plan: CEZ:AV0Z10030501 Keywords : reference systems * astrometry * catalogs Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.259, year: 2007

  8. Reframing Student Affairs Leadership: An Analysis of Organizational Frames of Reference and Locus of Control

    Science.gov (United States)

    Tull, Ashley; Freeman, Jerrid P.

    2011-01-01

    Examined in this study were the identified frames of reference and locus of control used by 478 student affairs administrators. Administrator responses were examined to identify frames of reference most commonly used and their preference order. Locus of control most commonly used and the relationship between frames of reference and locus of…

  9. The frames of reference of the motor-visual aftereffect.

    Directory of Open Access Journals (Sweden)

    Guido Barchiesi

    Full Text Available Repeatedly performing similar motor acts produces short-term adaptive changes in the agent's motor system. One striking use-dependent effect is the motor-to-visual aftereffect (MVA, a short-lasting negative bias in the conceptual categorization of visually-presented training-related motor behavior. The MVA is considered the behavioral counterpart of the adaptation of visuomotor neurons that code for congruent executed and observed motor acts. Here we characterize which features of the motor training generate the MVA, along 3 main dimensions: a the relative role of motor acts vs. the semantics of the task-set; b the role of muscular-specific vs. goal-specific training and c the spatial frame of reference with respect to the whole body. Participants were asked to repeatedly push or pull some small objects in a bowl as we varied different components of adapting actions across three experiments. The results show that a the semantic value of the instructions given to the participant have no role in generating the MVA, which depends only on the motor meaning of the training act; b both intrinsic body movements and extrinsic action goals contribute simultaneously to the genesis of the MVA and c changes in the relative position of the acting hand compared to the observed hand, when they do not involve changes to the movement performed or to the action meaning, do not have an effect on the MVA. In these series of experiments we confirm that recent motor experiences produce measurable changes in how humans see each others' actions. The MVA is an exquisite motor effect generated by two distinct motor sub-systems, one operating in an intrinsic, muscular specific, frame of reference and the other operating in an extrinsic motor space.

  10. A Global Moving Hotspot Reference Frame: How well it fits?

    Science.gov (United States)

    Doubrovine, P. V.; Steinberger, B.; Torsvik, T. H.

    2010-12-01

    Since the early 1970s, when Jason Morgan proposed that hotspot tracks record motion of lithosphere over deep-seated mantle plumes, the concept of fixed hotspots has dominated the way we think about absolute plate reconstructions. In the last decade, with compelling evidence for southward drift of the Hawaiian hotspot from paleomagnetic studies, and for the relative motion between the Pacific and Indo-Atlantic hotspots from refined plate circuit reconstructions, the perception changed and a global moving hotspot reference frame (GMHRF) was introduced, in which numerical models of mantle convection and advection of plume conduits in the mantle flow were used to estimate hotspot motion. This reference frame showed qualitatively better performance in fitting hotspot tracks globally, but the error analysis and formal estimates of the goodness of fitted rotations were lacking in this model. Here we present a new generation of the GMHRF, in which updated plate circuit reconstructions and radiometric age data from the hotspot tracks were combined with numerical models of plume motion, and uncertainties of absolute plate rotations were estimated through spherical regression analysis. The overall quality of fit was evaluated using a formal statistical test, by comparing misfits produced by the model with uncertainties assigned to the data. Alternative plate circuit models linking the Pacific plate to the plates of Indo-Atlantic hemisphere were tested and compared to the fixed hotspot models with identical error budgets. Our results show that, with an appropriate choice of the Pacific plate circuit, it is possible to reconcile relative plate motions and modeled motions of mantle plumes globally back to Late Cretaceous time (80 Ma). In contrast, all fixed hotspot models failed to produce acceptable fits for Paleogene to Late Cretaceous time (30-80 Ma), highlighting significance of relative motion between the Pacific and Indo-Atlantic hotspots during this interval. The

  11. UTC(SU) and EOP(SU) - the only legal reference frames of Russian Federation

    Science.gov (United States)

    Koshelyaevsky, Nikolay B.; Blinov, Igor Yu; Pasynok, Sergey L.

    2015-08-01

    There are two legal time reference frames in Russian Federation. UTC(SU) deals with atomic time and play a role of reference for legal timing through the whole country. The other one, EOP(SU), deals with Earth's orientation parameters and provides the official EOP data for scientific, technical and metrological applications in Russia.The atomic time is based on two essential hardware components: primary Cs fountain standards and ensemble of continuously operating H-masers as a time unit/time scale keeper. Basing on H-maser intercomparison system data, regular H-maser frequency calibration against Cs standards and time algorithm autonomous TA(SU) time scale is maintained by the Main Metrological Center. Since 2013 time unit in TA(SU) is the second (SU) reproduced independently by VNIIFTRI Cs primary standards in accordance to it’s definition in the SI. UTC(SU) is relied on TA(SU) and steering to UTC basing on TWSTFT/GNSS time link data. As a result TA(SU) stability level relative to TT considerably exceeds 1×10-15 for sample time one month and more, RMS[UTC-UTC(SU)] ≤ 3 ns for the period of 2013-2015. UTC(SU) is broadcasted by different national means such as specialized radio and TV stations, NTP servers and GLONASS. Signals of Russian radio stations contains DUT1 and dUT1 values at 0.1s and 0.02s resolution respectively.The definitive EOP(SU) are calculated by the Main Metrological Center basing on composition of the eight independent individual EOP data streams delivered by four Russian analysis centers: VNIIFTRI, Institute of Applied Astronomy, Information-Analytical Center of Russian Space Agency and Analysis Center of Russian Space Agency. The accuracy of ultra-rapid EOP values for 2014 is estimated ≤ 0.0006" for polar motion, ≤ 70 microseconds for UT1-UTC and ≤ 0.0003" for celestial pole offsets respectively.The other VNIIFTRI EOP activities can be grouped in three basic directions:- arrangement and carrying out GNSS and SLR observations at five

  12. GGSP: Realisation and maintenance of the Galileo Terrestrial Reference Frame

    Science.gov (United States)

    Ggsp Prototype Team; Gendt, G.; Altamimi, Z.; Dach, R.; Söhne, W.; Springer, T.; GGSP Prototype Team

    2011-01-01

    The realisation and maintenance of a Galileo Terrestrial Reference Frame (GTRF) is the main function of the Galileo Geodetic Service Provider (GGSP). The GTRF shall be compatible with the latest International Terrestrial Reference Frame (ITRF) within a precision level of 3 cm (2 sigma). The connection to the ITRF is realized and validated by stations of the International GNSS Service (IGS) and by geodetic local ties to stations equipped with other geodetic techniques. It is demonstrated that this GTRF can be maintained by including the Galileo Signal-in-Space data, once Galileo reaches its operational stage.The GGSP will also provide additional products, such as Earth Rotation Parameters, satellites orbits, clock corrections for satellites and stations, which will be offered to the Galileo user community to have most precise access to the GTRF and will be used to monitor the accuracy of the corresponding Galileo Mission Segment.The GGSP was built up in time, and for a final demonstration the full system was operated for an interval of 6 months. During that time also microwave data from the two active GIOVE satellites were used.The GGSP Consortium followed the most up to date IGS standards of weekly processing during seven monthly campaigns (November 2006 to June 2008) and a continuous processing from September 2008 to February 2009 delivering several versions of the GTRF. The latest GTRF solution (GTRF09v01) has an RMS position difference with respect to the ITRF2005 computed over the 71 common stations of 1.1 and 2.9 mm in the horizontal and vertical components, respectively. The RMS velocity differences are 0.3 and 0.6 mm/y, respectively. The GGSP GPS satellite orbits and clock corrections agree with the IGS Final products at a level of 5-11 mm and 0.02-0.03 ns, respectively.The quality of the GIOVE orbits is at a level of 20-30 cm. The Hydrogen-Maser on board of GIOVE-B is nearly one order of magnitude better than the GPS satellite clocks.

  13. Electrodynamics in Arbitrary Reference Frames and in Arbitrary Material Media

    International Nuclear Information System (INIS)

    Horzela, A.; Kapuscik, E.; Widomski, M.

    1999-01-01

    Full text: The investigation of electromagnetic phenomena in material media still belongs to the most difficult tasks of electrodynamics. Complexity and variability of material media practically exclude effective applications of methods and computational techniques elaborated in the framework of standard microscopic electrodynamics with classical vacuum as a ground state. In order to obtain satisfactorily exact descriptions of electromagnetic properties of complex material media one is enforced to use methods and approximations which are difficult to control. Moreover, they usually break covariance properties and the results obtained are valid in one reference frame which choice remains subjective and model dependent. Some time ago we have proposed a reformulation of Maxwell electrodynamics which opens new ways in study of electromagnetic processes in material media. The formalism gets rid of assumptions characteristic for vacuum electrodynamics only and it avoids the usage of constitutive relations as primary relations put on quantities needed for a complete description of an electromagnetic system. Fundamental properties of all electromagnetic quantities are their uniquely defined transformation rules and their analysis allows to determine the possible relations between them. Within such a scheme it is possible to introduce constitutive relations which do not have analogies in macroscopic classical electrodynamics. They may be used in description of microscopic electromagnetic processes in a different way than it is done in the framework of quantum electrodynamics. (author)

  14. Post-Newtonian Reference Frames For Advanced Theory Of The Lunar Motion And For A New Generation Of Lunar Laser Ranging

    International Nuclear Information System (INIS)

    Xie, Y.; Kopeikon, S.

    2010-01-01

    We overview a set of post-Newtonian reference frames for a comprehensive study of the orbital dynamics and rotational motion of Moon and Earth by means of lunar laser ranging (LLR). We employ a scalar-tensor theory of gravity depending on two post-Newtonian parameters, and , and utilize the relativistic resolutions on reference frames adopted by the International Astronomical Union (IAU) in 2000. We assume that the solar system is isolated and space-time is asymptotically flat at infinity. The primary reference frame covers the entire space-time, has its origin at the solar-system barycenter (SSB) and spatial axes stretching up to infinity. The SSB frame is not rotating with respect to a set of distant quasars that are forming the International Celestial Reference Frame (ICRF). The secondary reference frame has its origin at the Earth-Moon barycenter (EMB). The EMB frame is locally-inertial and is not rotating dynamically in the sense that equation of motion of a test particle moving with respect to the EMB frame, does not contain the Coriolis and centripetal forces. Two other local frames geocentric (GRF) and selenocentric (SRF) have their origins at the center of mass of Earth and Moon respectively and do not rotate dynamically. Each local frame is subject to the geodetic precession both with respect to other local frames and with respect to the ICRF because of their relative motion with respect to each other. Theoretical advantage of the dynamically non-rotating local frames is in a more simple mathematical description. Each local frame can be aligned with the axes of ICRF after applying the matrix of the relativistic precession. The set of one global and three local frames is introduced in order to fully decouple the relative motion of Moon with respect to Earth from the orbital motion of the Earth-Moon barycenter as well as to connect the coordinate description of the lunar motion, an observer on Earth, and a retro-reflector on Moon to directly measurable

  15. The reference frame for encoding and retention of motion depends on stimulus set size.

    Science.gov (United States)

    Huynh, Duong; Tripathy, Srimant P; Bedell, Harold E; Öğmen, Haluk

    2017-04-01

    The goal of this study was to investigate the reference frames used in perceptual encoding and storage of visual motion information. In our experiments, observers viewed multiple moving objects and reported the direction of motion of a randomly selected item. Using a vector-decomposition technique, we computed performance during smooth pursuit with respect to a spatiotopic (nonretinotopic) and to a retinotopic component and compared them with performance during fixation, which served as the baseline. For the stimulus encoding stage, which precedes memory, we found that the reference frame depends on the stimulus set size. For a single moving target, the spatiotopic reference frame had the most significant contribution with some additional contribution from the retinotopic reference frame. When the number of items increased (Set Sizes 3 to 7), the spatiotopic reference frame was able to account for the performance. Finally, when the number of items became larger than 7, the distinction between reference frames vanished. We interpret this finding as a switch to a more abstract nonmetric encoding of motion direction. We found that the retinotopic reference frame was not used in memory. Taken together with other studies, our results suggest that, whereas a retinotopic reference frame may be employed for controlling eye movements, perception and memory use primarily nonretinotopic reference frames. Furthermore, the use of nonretinotopic reference frames appears to be capacity limited. In the case of complex stimuli, the visual system may use perceptual grouping in order to simplify the complexity of stimuli or resort to a nonmetric abstract coding of motion information.

  16. Examining egocentric and allocentric frames of reference in virtual space systems

    NARCIS (Netherlands)

    Friedman, A.

    2005-01-01

    The aim of this paper is to examine the egocentric and allocentric frames of reference, through evidence from both gesture and linguistic communication. The action of frames of reference, helps the user refer to the agent as a base for movement or to the object as a guiding point. We will show that

  17. An Automated Reference Frame Selection (ARFS) Algorithm for Cone Imaging with Adaptive Optics Scanning Light Ophthalmoscopy.

    Science.gov (United States)

    Salmon, Alexander E; Cooper, Robert F; Langlo, Christopher S; Baghaie, Ahmadreza; Dubra, Alfredo; Carroll, Joseph

    2017-04-01

    To develop an automated reference frame selection (ARFS) algorithm to replace the subjective approach of manually selecting reference frames for processing adaptive optics scanning light ophthalmoscope (AOSLO) videos of cone photoreceptors. Relative distortion was measured within individual frames before conducting image-based motion tracking and sorting of frames into distinct spatial clusters. AOSLO images from nine healthy subjects were processed using ARFS and human-derived reference frames, then aligned to undistorted AO-flood images by nonlinear registration and the registration transformations were compared. The frequency at which humans selected reference frames that were rejected by ARFS was calculated in 35 datasets from healthy subjects, and subjects with achromatopsia, albinism, or retinitis pigmentosa. The level of distortion in this set of human-derived reference frames was assessed. The average transformation vector magnitude required for registration of AOSLO images to AO-flood images was significantly reduced from 3.33 ± 1.61 pixels when using manual reference frame selection to 2.75 ± 1.60 pixels (mean ± SD) when using ARFS ( P = 0.0016). Between 5.16% and 39.22% of human-derived frames were rejected by ARFS. Only 2.71% to 7.73% of human-derived frames were ranked in the top 5% of least distorted frames. ARFS outperforms expert observers in selecting minimally distorted reference frames in AOSLO image sequences. The low success rate in human frame choice illustrates the difficulty in subjectively assessing image distortion. Manual reference frame selection represented a significant barrier to a fully automated image-processing pipeline (including montaging, cone identification, and metric extraction). The approach presented here will aid in the clinical translation of AOSLO imaging.

  18. Frames of reference for self-evaluation of ability in mathematics.

    Science.gov (United States)

    Skaalvik, Sidsel; Skaalvik, Einar M

    2004-04-01

    Measures of eight frame-specific self-evaluations of ability in mathematics were used to predict general mathematics self-concept and self-efficacy. Participants were 900 Norwegian students in Grade 6 (n = 277), Grade 9 (n = 236), Grade 11 (n = 263), and adult students attending senior high school (n = 124). Four items measured frame-specific self-evaluation of achievement based on external frames of reference whereas four items measured frame-specific self-evaluation based on internal frames of reference. Regression analyses were used to test relations between the frame-specific self-evaluations and general mathematics self-concept and self-efficacy. The analyses indicated that self-evaluation based on comparison with other students in class (an external frame of reference) and on comparison of mathematics achievement with achievement in other school subjects (an internal frame of reference) were robust predictors of both mathematics self-concept and self-efficacy. The analyses also indicated that students are using multiple frames of reference when evaluating their mathematics ability. Implications of the result for the internal-external frame of reference model are discussed.

  19. Geometric Cues, Reference Frames, and the Equivalence of Experienced-Aligned and Novel-Aligned Views in Human Spatial Memory

    Science.gov (United States)

    Kelly, Jonathan W.; Sjolund, Lori A.; Sturz, Bradley R.

    2013-01-01

    Spatial memories are often organized around reference frames, and environmental shape provides a salient cue to reference frame selection. To date, however, the environmental cues responsible for influencing reference frame selection remain relatively unknown. To connect research on reference frame selection with that on orientation via…

  20. Effect of Laterally Wedged Insoles on the External Knee Adduction Moment across Different Reference Frames.

    Directory of Open Access Journals (Sweden)

    Satoshi Yamaguchi

    Full Text Available Biomechanical effects of laterally wedged insoles are assessed by reduction in the knee adduction moment. However, the degree of reduction may vary depending on the reference frame with which it is calculated. The purpose of this study was to clarify the effect of reference frame on the reduction in the knee adduction moment by laterally wedged insoles.Twenty-nine healthy participants performed gait trials with a laterally wedged insole and with a flat insole as a control. The knee adduction moment, including the first and second peaks and the angular impulse, were calculated using four different reference frames: the femoral frame, tibial frame, laboratory frame and the Joint Coordinate System.There were significant effects of reference frame on the knee adduction moment first and second peaks (P < 0.001 for both variables, while the effect was not significant for the angular impulse (P = 0.84. No significant interaction between the gait condition and reference frame was found in either of the knee adduction moment variables (P = 0.99 for all variables, indicating that the effects of laterally wedged insole on the knee adduction moments were similar across the four reference frames. On the other hand, the average percent changes ranged from 9% to 16% for the first peak, from 16% to 18% for the second peak and from 17% to 21% for the angular impulse when using the different reference frames.The effects of laterally wedged insole on the reduction in the knee adduction moment were similar across the reference frames. On the other hand, Researchers need to recognize that when the percent change was used as the parameter of the efficacy of laterally wedged insole, the choice of reference frame may influence the interpretation of how laterally wedged insoles affect the knee adduction moment.

  1. Tracking Down Abstract Linguistic Meaning: Neural Correlates of Spatial Frame of Reference Ambiguities in Language

    NARCIS (Netherlands)

    Janzen, G.; Haun, D.B.M.; Levinson, S.C.

    2012-01-01

    This functional magnetic resonance imaging (fMRI) study investigates a crucial parameter in spatial description, namely variants in the frame of reference chosen. Two frames of reference are available in European languages for the description of small-scale assemblages, namely the intrinsic (or

  2. Tracking down abstract linguistic meaning: neural correlates of spatial frame of reference ambiguities in language.

    Directory of Open Access Journals (Sweden)

    Gabriele Janzen

    Full Text Available This functional magnetic resonance imaging (fMRI study investigates a crucial parameter in spatial description, namely variants in the frame of reference chosen. Two frames of reference are available in European languages for the description of small-scale assemblages, namely the intrinsic (or object-oriented frame and the relative (or egocentric frame. We showed participants a sentence such as "the ball is in front of the man", ambiguous between the two frames, and then a picture of a scene with a ball and a man--participants had to respond by indicating whether the picture did or did not match the sentence. There were two blocks, in which we induced each frame of reference by feedback. Thus for the crucial test items, participants saw exactly the same sentence and the same picture but now from one perspective, now the other. Using this method, we were able to precisely pinpoint the pattern of neural activation associated with each linguistic interpretation of the ambiguity, while holding the perceptual stimuli constant. Increased brain activity in bilateral parahippocampal gyrus was associated with the intrinsic frame of reference whereas increased activity in the right superior frontal gyrus and in the parietal lobe was observed for the relative frame of reference. The study is among the few to show a distinctive pattern of neural activation for an abstract yet specific semantic parameter in language. It shows with special clarity the nature of the neural substrate supporting each frame of spatial reference.

  3. Calibration of Robot Reference Frames for Enhanced Robot Positioning Accuracy

    OpenAIRE

    Cheng, Frank Shaopeng

    2008-01-01

    This chapter discussed the importance and methods of conducting robot workcell calibration for enhancing the accuracy of the robot TCP positions in industrial robot applications. It shows that the robot frame transformations define the robot geometric parameters such as joint position variables, link dimensions, and joint offsets in an industrial robot system. The D-H representation allows the robot designer to model the robot motion geometry with the four standard D-H parameters. The robot k...

  4. Four-Year-Olds Use a Mixture of Spatial Reference Frames.

    Science.gov (United States)

    Negen, James; Nardini, Marko

    2015-01-01

    Keeping track of unseen objects is an important spatial skill. In order to do this, people must situate the object in terms of different frames of reference, including body position (egocentric frame of reference), landmarks in the surrounding environment (extrinsic frame reference), or other attached features (intrinsic frame of reference). Nardini et al. hid a toy in one of 12 cups in front of children, turned the array when they were not looking, and then asked them to point to the cup with the toy. This forced children to use the intrinsic frame (information about the array of cups) to locate the hidden toy. Three-year-olds made systematic errors by using the wrong frame of reference, 4-year-olds were at chance, and only 5- and 6-year-olds were successful. Can we better understand the developmental change that takes place at four years? This paper uses a modelling approach to re-examine the data and distinguish three possible strategies that could lead to the previous results at four years: (1) Children were choosing cups randomly, (2) Children were pointing between the egocentric/extrinsic-cued location and the correct target, and (3) Children were pointing near the egocentric/extrinsic-cued location on some trials and near the target on the rest. Results heavily favor the last possibility: 4-year-olds were not just guessing or trying to combine the available frames of reference. They were using the intrinsic frame on some trials, but not doing so consistently. These insights suggest that accounts of improving spatial performance at 4 years need to explain why there is a mixture of responses. Further application of the selected model also suggests that children become both more reliant on the correct frame and more accurate with any chosen frame as they mature.

  5. Four-Year-Olds Use a Mixture of Spatial Reference Frames.

    Directory of Open Access Journals (Sweden)

    James Negen

    Full Text Available Keeping track of unseen objects is an important spatial skill. In order to do this, people must situate the object in terms of different frames of reference, including body position (egocentric frame of reference, landmarks in the surrounding environment (extrinsic frame reference, or other attached features (intrinsic frame of reference. Nardini et al. hid a toy in one of 12 cups in front of children, turned the array when they were not looking, and then asked them to point to the cup with the toy. This forced children to use the intrinsic frame (information about the array of cups to locate the hidden toy. Three-year-olds made systematic errors by using the wrong frame of reference, 4-year-olds were at chance, and only 5- and 6-year-olds were successful. Can we better understand the developmental change that takes place at four years? This paper uses a modelling approach to re-examine the data and distinguish three possible strategies that could lead to the previous results at four years: (1 Children were choosing cups randomly, (2 Children were pointing between the egocentric/extrinsic-cued location and the correct target, and (3 Children were pointing near the egocentric/extrinsic-cued location on some trials and near the target on the rest. Results heavily favor the last possibility: 4-year-olds were not just guessing or trying to combine the available frames of reference. They were using the intrinsic frame on some trials, but not doing so consistently. These insights suggest that accounts of improving spatial performance at 4 years need to explain why there is a mixture of responses. Further application of the selected model also suggests that children become both more reliant on the correct frame and more accurate with any chosen frame as they mature.

  6. Full-Frame Reference for Test Photo of Moon

    Science.gov (United States)

    2005-01-01

    This pair of views shows how little of the full image frame was taken up by the Moon in test images taken Sept. 8, 2005, by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter. The Mars-bound camera imaged Earth's Moon from a distance of about 10 million kilometers (6 million miles) away -- 26 times the distance between Earth and the Moon -- as part of an activity to test and calibrate the camera. The images are very significant because they show that the Mars Reconnaissance Orbiter spacecraft and this camera can properly operate together to collect very high-resolution images of Mars. The target must move through the camera's telescope view in just the right direction and speed to acquire a proper image. The day's test images also demonstrate that the focus mechanism works properly with the telescope to produce sharp images. Out of the 20,000-pixel-by-6,000-pixel full frame, the Moon's diameter is about 340 pixels, if the full Moon could be seen. The illuminated crescent is about 60 pixels wide, and the resolution is about 10 kilometers (6 miles) per pixel. At Mars, the entire image region will be filled with high-resolution information. The Mars Reconnaissance Orbiter, launched on Aug. 12, 2005, is on course to reach Mars on March 10, 2006. After gradually adjusting the shape of its orbit for half a year, it will begin its primary science phase in November 2006. From the mission's planned science orbit about 300 kilometers (186 miles) above the surface of Mars, the high resolution camera will be able to discern features as small as one meter or yard across. The Mars Reconnaissance Orbiter mission is managed by NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, for the NASA Science Mission Directorate. Lockheed Martin Space Systems, Denver, prime contractor for the project, built the spacecraft. Ball Aerospace & Technologies Corp., Boulder, Colo., built the High

  7. KSM03 harmonic development of the Earth tide-generating potential in terrestrial reference frame

    Science.gov (United States)

    Kudryavtsev, S. M.

    2005-09-01

    The KSM03 harmonic development of the Earth tide-generating potential of Kudryavtsev (2004) is re-calculated into the Terrestrial reference frame and presented in the standard HW95 (Hartmann and Wenzel 1995) normalization and format.

  8. Global Navigation Satellite System (GNSS) Final Orbit/Reference Frame Product Summary from NASA CDDIS

    Data.gov (United States)

    National Aeronautics and Space Administration — This derived product set consists of Global Navigation Satellite System Final Orbit/Reference Frame Product Summary from the NASA Crustal Dynamics Data Information...

  9. Combining Laws of Mechanics and Hydrostatics in Non-Inertial Reference Frames

    OpenAIRE

    M. Blokh

    2015-01-01

    Method of combined teaching laws of classical mechanics and hydrostatics in non-inertial reference frames for undergraduate students is proposed. Pressure distribution in a liquid (or gas) moving with acceleration is considered. Combined effect of hydrostatic force and force of inertia on a body immersed in a liquid can lead to paradoxical results, in a motion of pendulum in particular. The body motion under Stokes force influence and forces in rotating reference frames a...

  10. The visual system encodes others' direction of gaze in a first-person frame of reference.

    Science.gov (United States)

    Palmer, Colin J; Clifford, Colin W G

    2017-11-01

    The primate visual system contains specialised neural mechanisms for encoding the direction of others' gaze. A foundational question that we can ask in this domain concerns the frame of reference in which another person's gaze is represented. Electrophysiological recordings in macaque monkeys suggest that direction of gaze might be encoded relative to the observer (i.e., in a first person reference frame) or relative to the head or body of the stimulus (i.e., in a second person reference frame). Here we use sensory adaptation to gaze direction as a psychophysical tool to probe how this property of the environment is represented in the human visual system. We find that strong perceptual aftereffects occur following adaptation to images that share a common direction of gaze in the first person reference frame, but vary in their direction of gaze in the second person reference frame. In contrast, sensory aftereffects do not occur following adaptation to images that share a common direction of gaze in the second person reference frame. These findings suggest that the adaptive coding of gaze direction in the human visual system occurs primarily in a first-person coordinate system. These data also provide strong support for perceptual constancy in the context of perceived gaze direction, implying that the direction of others' attention is represented in the brain as a higher-level perceptual property abstracted from lower-level cues (e.g., iris position and head rotation). Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Updating of visual orientation in a gravity-based reference frame.

    Science.gov (United States)

    Niehof, Nynke; Tramper, Julian J; Doeller, Christian F; Medendorp, W Pieter

    2017-10-01

    The brain can use multiple reference frames to code line orientation, including head-, object-, and gravity-centered references. If these frames change orientation, their representations must be updated to keep register with actual line orientation. We tested this internal updating during head rotation in roll, exploiting the rod-and-frame effect: The illusory tilt of a vertical line surrounded by a tilted visual frame. If line orientation is stored relative to gravity, these distortions should also affect the updating process. Alternatively, if coding is head- or frame-centered, updating errors should be related to the changes in their orientation. Ten subjects were instructed to memorize the orientation of a briefly flashed line, surrounded by a tilted visual frame, then rotate their head, and subsequently judge the orientation of a second line relative to the memorized first while the frame was upright. Results showed that updating errors were mostly related to the amount of subjective distortion of gravity at both the initial and final head orientation, rather than to the amount of intervening head rotation. In some subjects, a smaller part of the updating error was also related to the change of visual frame orientation. We conclude that the brain relies primarily on a gravity-based reference to remember line orientation during head roll.

  12. NChina16: A stable geodetic reference frame for geological hazard studies in North China

    Science.gov (United States)

    Wang, Guoquan; Bao, Yan; Gan, Weijun; Geng, Jianghui; Xiao, Gengru; Shen, Jack S.

    2018-04-01

    We have developed a stable North China Reference Frame 2016 (NChina16) using five years of continuous GPS observations (2011.8-2016.8) from 12 continuously operating reference stations (CORS) fixed to the North China Craton. Applications of NChina16 in landslide and subsidence studies are illustrated in this article. A method for realizing a regional geodetic reference frame is introduced. The primary result of this study is the seven parameters for transforming Cartesian ECEF (Earth-Centered, Earth-Fixed) coordinates X, Y, and Z from the International GNSS Service Reference Frame 2008 (IGS08) to NChina16. The seven parameters include the epoch that is used to align the regional reference frame to IGS08 and the time derivatives of three translations and three rotations. The GIPSY-OASIS (V6.4) software package was used to obtain the precise point positioning (PPP) daily solutions with respect to IGS08. The frame stability of NChina16 is approximately 0.5 mm/year in both horizontal and vertical directions. This study also developed a regional model for correcting seasonal motions superimposed into the vertical component of the GPS-derived displacement time series. Long-term GPS observations (1999-2016) from five CORS in North China were used to develop the seasonal model. According to this study, the PPP daily solutions with respect to NChina16 could achieve 2-3 mm horizontal accuracy and 4-5 mm vertical accuracy after being modified by the regional model. NChina16 will be critical to study geodynamic problems in North China, such as earthquakes, faulting, subsidence, and landslides. The regional reference frame will be periodically updated every few years to mitigate degradation of the frame with time and be synchronized with the update of IGS reference frame.

  13. A reference frame for blood volume in children and adolescents

    Directory of Open Access Journals (Sweden)

    Donckerwolcke Raymond

    2006-02-01

    Full Text Available Abstract Background Our primary purpose was to determine the normal range and variability of blood volume (BV in healthy children, in order to provide reference values during childhood and adolescence. Our secondary aim was to correlate these vascular volumes to body size parameters and pubertal stages, in order to determine the best normalisation parameter. Methods Plasma volume (PV and red cell volume (RCV were measured and F-cell ratio was calculated in 77 children with idiopathic nephrotic syndrome in drug-free remission (mean age, 9.8 ± 4.6 y. BV was calculated as the sum of PV and RCV. Due to the dependence of these values on age, size and sex, all data were normalised for body size parameters. Results BV normalised for lean body mass (LBM did not differ significantly by sex (p Conclusion LBM was the anthropometric index most closely correlated to vascular fluid volumes, independent of age, gender and pubertal stage.

  14. The Earth Orientation Catalog 4: An optical reference frame for monitoring Earth's orientation in the 20th century

    Czech Academy of Sciences Publication Activity Database

    Vondrák, Jan; Štefka, Vojtěch

    2010-01-01

    Roč. 509, - (2010), A3-1-A3-7 ISSN 0004-6361 R&D Projects: GA MŠk(CZ) LC506 Institutional research plan: CEZ:AV0Z10030501 Keywords : astrometry * reference systems * catalogs Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.410, year: 2010

  15. Burnham's celestial handbook

    CERN Document Server

    Burnham, Robert

    1978-01-01

    Volume II of a comprehensive three-part guide to celestial objects outside our solar system ranges from Chamaeleon to Orion. Features coordinates, classifications, physical descriptions, hundreds of visual aids. 1977 edition.

  16. Mesopotamian Celestial Divination

    Science.gov (United States)

    Verderame, Lorenzo

    Celestial divination was an important aspect of scholarly activity in Mesopotamia. Several hundred cuneiform tablets attest to its practice and provide details of the different types of omens that were drawn from observations of the sky. This chapter outlines the sources of celestial divination in Mesopotamia and traces the development of the divinatory tradition from the late third millennium BC down to the end of the first millennium BC.

  17. Thinking inside the box: Spatial frames of reference for drawing in Williams syndrome and typical development.

    Science.gov (United States)

    Hudson, Kerry D; Farran, Emily K

    2017-09-01

    Successfully completing a drawing relies on the ability to accurately impose and manipulate spatial frames of reference for the object that is being drawn and for the drawing space. Typically developing (TD) children use cues such as the page boundary as a frame of reference to guide the orientation of drawn lines. Individuals with Williams syndrome (WS) typically produce incohesive drawings; this is proposed to reflect a local processing bias. Across two studies, we provide the first investigation of the effect of using a frame of reference when drawing simple lines and shapes in WS and TD groups (matched for non-verbal ability). Individuals with WS (N=17 Experiment 1; N=18 Experiment 2) and TD children matched by non-verbal ability drew single lines (Experiment One) and whole shapes (Experiment Two) within a neutral, incongruent or congruent frame. The angular deviation of the drawn line/shape, relative to the model line/shape, was measured. Both groups were sensitive to spatial frames of reference when drawing single lines and whole shapes, imposed by a frame around the drawing space. A local processing bias in WS cannot explain poor drawing performance in WS. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  18. Network-Aware Reference Frame Control for Error-Resilient H.264/AVC Video Streaming Service

    Directory of Open Access Journals (Sweden)

    Hui-Seon Gang

    2016-01-01

    Full Text Available To provide high-quality video streaming services in a mobile communication network, a large bandwidth and reliable channel conditions are required. However, mobile communication services still encounter limited bandwidth and varying channel conditions. The streaming video system compresses video with motion estimation and compensation using multiple reference frames. The multiple reference frame structure can reduce the compressed bit rate of video; however, it can also cause significant error propagation when the video in the channel is damaged. Even though the streaming video system includes error-resilience tools to mitigate quality degradation, error propagation is inevitable because all errors can not be refreshed under the multiple reference frame structure. In this paper, a new network-aware error-resilient streaming video system is introduced. The proposed system can mitigate error propagation by controlling the number of reference frames based on channel status. The performance enhancement is demonstrated by comparing the proposed method to the conventional streaming system using static number of reference frames.

  19. Magnetic resonance described in the excitation dependent rotating frame of reference.

    Science.gov (United States)

    Tahayori, Bahman; Johnston, Leigh A; Mareels, Iven M Y; Farrell, Peter M

    2008-01-01

    An excitation dependent rotating frame of reference to observe the magnetic resonance phenomenon is introduced in this paper that, to the best of our knowledge, has not been used previously in the nuclear magnetic resonance context. The mathematical framework for this new rotating frame of reference is presented based on time scaling the Bloch equation after transformation to the classical rotating frame of reference whose transverse plane is rotating at the Larmor frequency. To this end, the Bloch equation is rewritten in terms of a magnetisation vector observed from the excitation dependent rotating frame of reference. The resultant Bloch equation is referred to as the time scaled Bloch equation. In the excitation dependent rotating frame of reference whose coordinates are rotating at the instantaneous Rabi frequency the observed magnetisation vector is a much slower signal than the true magnetisation in the rotating frame of reference. As a result the ordinary differential equation solvers have the ability to solve the time scaled version of the Bloch equation with a larger step size resulting in a smaller number of samples for solving the equation to a desired level of accuracy. The simulation results for different types of excitation are presented in this paper. This method may be used in true Bloch simulators in order to reduce the simulation time or increase the accuracy of the numerical solution. Moreover, the time scaled Bloch equation may be employed to determine the optimal excitation pattern in magnetic resonance imaging as well as designing pulses with better slice selectivity which is an active area of research in this field.

  20. Celestial mechanics and astrodynamics theory and practice

    CERN Document Server

    Gurfil, Pini

    2016-01-01

    This volume is designed as an introductory text and reference book for graduate students, researchers and practitioners in the fields of astronomy, astrodynamics, satellite systems, space sciences and astrophysics. The purpose of the book is to emphasize the similarities between celestial mechanics and astrodynamics, and to present recent advances in these two fields so that the reader can understand the inter-relations and mutual influences. The juxtaposition of celestial mechanics and astrodynamics is a unique approach that is expected to be a refreshing attempt to discuss both the mechanics of space flight and the dynamics of celestial objects. “Celestial Mechanics and Astrodynamics: Theory and Practice” also presents the main challenges and future prospects for the two fields in an elaborate, comprehensive and rigorous manner. The book presents homogenous and fluent discussions of the key problems, rendering a portrayal of recent advances in the field together with some basic concepts and essential in...

  1. Influences of indigenous language on spatial frames of reference in Aboriginal English

    Science.gov (United States)

    Edmonds-Wathen, Cris

    2014-06-01

    The Aboriginal English spoken by Indigenous children in remote communities in the Northern Territory of Australia is influenced by the home languages spoken by themselves and their families. This affects uses of spatial terms used in mathematics such as `in front' and `behind.' Speakers of the endangered Indigenous Australian language Iwaidja use the intrinsic frame of reference in contexts where speakers of Standard Australian English use the relative frame of reference. Children speaking Aboriginal English show patterns of use that parallel the Iwaidja contexts. This paper presents detailed examples of spatial descriptions in Iwaidja and Aboriginal English that demonstrate the parallel patterns of use. The data comes from a study that investigated how an understanding of spatial frame of reference in Iwaidja could assist teaching mathematics to Indigenous language-speaking students. Implications for teaching mathematics are explored for teachers without previous experience in a remote Indigenous community.

  2. Parametrized post-Newtonian theory of reference frames, multipolar expansions and equations of motion in the N-body problem

    International Nuclear Information System (INIS)

    Kopeikin, Sergei; Vlasov, Igor

    2004-01-01

    Post-Newtonian relativistic theory of astronomical reference frames based on Einstein's general theory of relativity was adopted by General Assembly of the International Astronomical Union in 2000. This theory is extended in the present paper by taking into account all relativistic effects caused by the presumable existence of a scalar field and parametrized by two parameters, β and γ, of the parametrized post-Newtonian (PPN) formalism. We use a general class of the scalar-tensor (Brans-Dicke type) theories of gravitation to work out PPN concepts of global and local reference frames for an astronomical N-body system. The global reference frame is a standard PPN coordinate system. A local reference frame is constructed in the vicinity of a weakly self-gravitating body (a sub-system of the bodies) that is a member of the astronomical N-body system. Such local inertial frame is required for unambiguous derivation of the equations of motion of the body in the field of other members of the N-body system and for construction of adequate algorithms for data analysis of various gravitational experiments conducted in ground-based laboratories and/or on board of spacecrafts in the solar system.We assume that the bodies comprising the N-body system have weak gravitational field and move slowly. At the same time we do not impose any specific limitations on the distribution of density, velocity and the equation of state of the body's matter. Scalar-tensor equations of the gravitational field are solved by making use of the post-Newtonian approximations so that the metric tensor and the scalar field are obtained as functions of the global and local coordinates. A correspondence between the local and global coordinate frames is found by making use of asymptotic expansion matching technique. This technique allows us to find a class of the post-Newtonian coordinate transformations between the frames as well as equations of translational motion of the origin of the local frame

  3. Defining an absolute reference frame for 'clumped' isotope studies of CO 2

    Science.gov (United States)

    Dennis, Kate J.; Affek, Hagit P.; Passey, Benjamin H.; Schrag, Daniel P.; Eiler, John M.

    2011-11-01

    We present a revised approach for standardizing and reporting analyses of multiply substituted isotopologues of CO 2 (i.e., 'clumped' isotopic species, especially the mass-47 isotopologues). Our approach standardizes such data to an absolute reference frame based on theoretical predictions of the abundances of multiply-substituted isotopologues in gaseous CO 2 at thermodynamic equilibrium. This reference frame is preferred over an inter-laboratory calibration of carbonates because it enables all laboratories measuring mass 47 CO 2 to use a common scale that is tied directly to theoretical predictions of clumping in CO 2, regardless of the laboratory's primary research field (carbonate thermometry or CO 2 biogeochemistry); it explicitly accounts for mass spectrometric artifacts rather than convolving (and potentially confusing) them with chemical fractionations associated with sample preparation; and it is based on a thermodynamic equilibrium that can be experimentally established in any suitably equipped laboratory using commonly available materials. By analyzing CO 2 gases that have been subjected to established laboratory procedures known to promote isotopic equilibrium (i.e., heated gases and water-equilibrated CO 2), and by reference to thermodynamic predictions of equilibrium isotopic distributions, it is possible to construct an empirical transfer function that is applicable to data with unknown clumped isotope signatures. This transfer function empirically accounts for the fragmentation and recombination reactions that occur in electron impact ionization sources and other mass spectrometric artifacts. We describe the protocol necessary to construct such a reference frame, the method for converting gases with unknown clumped isotope compositions to this reference frame, and suggest a protocol for ensuring that all reported isotopic compositions (e.g., Δ 47 values; Eiler and Schauble, 2004; Eiler, 2007) can be compared among different laboratories and

  4. Decoherence-full subsystems and the cryptographic power of a private shared reference frame

    International Nuclear Information System (INIS)

    Bartlett, Stephen D.; Rudolph, Terry; Spekkens, Robert W.

    2004-01-01

    We show that private shared reference frames can be used to perform private quantum and private classical communication over a public quantum channel. Such frames constitute a type of private shared correlation, distinct from private classical keys or shared entanglement, useful for cryptography. We present optimally efficient schemes for private quantum and classical communication given a finite number of qubits transmitted over an insecure channel and given a private shared Cartesian frame and/or a private shared reference ordering of the qubits. We show that in this context, it is useful to introduce the concept of a decoherence-full subsystem, wherein every state is mapped to the completely mixed state under the action of the decoherence

  5. A New Synchronous Reference Frame-Based Method for Single-Phase Shunt Active Power Filters

    DEFF Research Database (Denmark)

    Monfared, Mohammad; Golestan, Saeed; Guerrero, Josep M.

    2013-01-01

    This paper deals with the design of a novel method in the synchronous reference frame (SRF) to extract the reference compensating current for single-phase shunt active power filters (APFs). Unlike previous works in the SRF, the proposed method has an innovative feature that it does not need the f...... the excellent performance of the suggested approach. Theoretical evaluations are confirmed by experimental results....

  6. Burnham's celestial handbook

    CERN Document Server

    Burnham, Robert

    1978-01-01

    Volume III of this three-part comprehensive guide to the thousands of celestial objects outside our solar system concludes with listings from Pavo through Vulpecula. Objects are grouped according to constellation, and their definitions feature names, coordinates, classifications, and physical descriptions. Additional notes offer fascinating historical information. Hundreds of visual aids. 1977 edition.

  7. Burnham's celestial handbook

    CERN Document Server

    Burnham, Robert

    1978-01-01

    Volume I of this comprehensive three-part guide to the thousands of celestial objects outside our solar system ranges from Andromeda through Cetus. Objects are grouped according to constellation, and their definitions feature names, coordinates, classifications, and physical descriptions. Additional notes offer fascinating historical information. Hundreds of visual aids. 1977 edition.

  8. The values underlying the Draft Common Frame of Reference: what role for fairness and 'social justice'?

    NARCIS (Netherlands)

    Hesselink, M.W.

    2008-01-01

    This study provides an in-depth analysis of the provisions of the draft Common Frame of Reference (DCFR), in order to assess if the DCFR perceives contract law only as a tool for regulating private law relations between equally strong parties or if it contains elements of 'social justice' in favour

  9. Higher?order ionospheric effects on the GPS reference frame and velocities

    NARCIS (Netherlands)

    Petrie, E.J.; King, M.A.; Moore, P.; Lavallée, D.A.

    2010-01-01

    We describe how GPS time series are influenced by higher?order ionospheric effects over the last solar cycle (1995–2008) and examine implications for geophysical studies. Using 14 years of globally reprocessed solutions, we demonstrate the effect on the reference frame. Including second? and

  10. Understanding Frame-of-Reference Training Success: A Social Learning Theory Perspective

    Science.gov (United States)

    Sulsky, Lorne M.; Kline, Theresa J. B.

    2007-01-01

    Employing the social learning theory (SLT) perspective on training, we analysed the effects of alternative frame-of-reference (FOR) training protocols on various criteria of training effectiveness. Undergraduate participants (N = 65) were randomly assigned to one of four FOR training conditions and a control condition. Training effectiveness was…

  11. Quantum mechanics in noninertial reference frames: Violations of the nonrelativistic equivalence principle

    International Nuclear Information System (INIS)

    Klink, W.H.; Wickramasekara, S.

    2014-01-01

    In previous work we have developed a formulation of quantum mechanics in non-inertial reference frames. This formulation is grounded in a class of unitary cocycle representations of what we have called the Galilean line group, the generalization of the Galilei group that includes transformations amongst non-inertial reference frames. These representations show that in quantum mechanics, just as is the case in classical mechanics, the transformations to accelerating reference frames give rise to fictitious forces. A special feature of these previously constructed representations is that they all respect the non-relativistic equivalence principle, wherein the fictitious forces associated with linear acceleration can equivalently be described by gravitational forces. In this paper we exhibit a large class of cocycle representations of the Galilean line group that violate the equivalence principle. Nevertheless the classical mechanics analogue of these cocycle representations all respect the equivalence principle. -- Highlights: •A formulation of Galilean quantum mechanics in non-inertial reference frames is given. •The key concept is the Galilean line group, an infinite dimensional group. •A large class of general cocycle representations of the Galilean line group is constructed. •These representations show violations of the equivalence principle at the quantum level. •At the classical limit, no violations of the equivalence principle are detected

  12. The Reciprocal Internal/External Frame of Reference Model Using Grades and Test Scores

    Science.gov (United States)

    Möller, Jens; Zimmermann, Friederike; Köller, Olaf

    2014-01-01

    Background: The reciprocal I/E model (RI/EM) combines the internal/external frame of reference model (I/EM) with the reciprocal effects model (REM). The RI/EM extends the I/EM longitudinally and the REM across domains. The model predicts that, within domains, mathematics and verbal achievement (VACH) and academic self-concept have positive effects…

  13. Asymptotically Matched Layer (AML) for transient wave propagation in a moving frame of reference

    DEFF Research Database (Denmark)

    Madsen, Stine Skov; Krenk, Steen

    2017-01-01

    The paper presents an Asymptotically Matched Layer (AML) formulation in a moving frame of reference for transient dynamic response of a multi-layer 2D half-space. A displacement based finite element formulation of the convected domain problem is presented together with the AML formulation in which...

  14. A robust WENO scheme for nonlinear waves in a moving reference frame

    DEFF Research Database (Denmark)

    Kontos, Stavros; Bingham, Harry B.; Lindberg, Ole

    2016-01-01

    For robust nonlinear wave simulation in a moving reference frame, we recast the free surface problem in Hamilton-Jacobi form and propose a Weighted Essentially Non-Oscillatory (WENO) scheme to automatically handle the upwinding of the convective term. A new automatic procedure for deriving the li...

  15. Layout Geometry in the Selection of Intrinsic Frames of Reference from Multiple Viewpoints

    Science.gov (United States)

    Mou, Weimin; Zhao, Mintao; McNamara, Timothy P.

    2007-01-01

    Four experiments investigated the roles of layout geometry in the selection of intrinsic frames of reference in spatial memory. Participants learned the locations of objects in a room from 2 or 3 viewing perspectives. One view corresponded to the axis of bilateral symmetry of the layout, and the other view(s) was (were) nonorthogonal to the axis…

  16. Teacher Frame of Reference and the Big-Fish-Little-Pond Effect

    Science.gov (United States)

    Ludtke, O.; Koller, O.; Marsh, H.W.; Trautwein, U.

    2005-01-01

    Teachers with an individualized teacher frame of reference (TFR) emphasize improvement in relation to prior achievement, effort, and learning. Individualized TFRs were hypothesized to enhance self-concept and reduce the negative effects associated with the big fish little pond effect (BFLPE). Math achievement and math self-concept data (2150…

  17. Conventional Synchronous Reference Frame Phase-Locked Loop Is An Adaptive Complex Filter

    DEFF Research Database (Denmark)

    Golestan, Saeed; Guerrero, Josep M.

    2015-01-01

    Despite the wide acceptance and use of the conventional synchronous reference frame phase-locked loop (SRFPLL) no transfer function describing its actual input-output relationship has been developed so far. Arguably, the absence of such transfer function has hampered the application of SRF...

  18. The Generalized Internal/External Frame of Reference Model: An Extension to Dimensional Comparison Theory

    Science.gov (United States)

    Möller, Jens; Müller-Kalthoff, Hanno; Helm, Friederike; Nagy, Nicole; Marsh, Herb W.

    2016-01-01

    The dimensional comparison theory (DCT) focuses on the effects of internal, dimensional comparisons (e.g., "How good am I in math compared to English?") on academic self-concepts with widespread consequences for students' self-evaluation, motivation, and behavioral choices. DCT is based on the internal/external frame of reference model…

  19. Analysis, Design, and Experimental Verification of A Synchronous Reference Frame Voltage Control for Single-Phase Inverters

    DEFF Research Database (Denmark)

    Monfared, Mohammad; Golestan, Saeed; Guerrero, Josep M.

    2014-01-01

    Control of three-phase power converters in the synchronous reference frame is now a mature and well developed research topic. However, for single-phase converters, it is not as well-established as three-phase applications. This paper deals with the design of a synchronous reference frame multi......-loop control strategy for single phase inverter-based islanded distributed generation (DG) systems. The proposed controller uses a synchronous reference frame PI (SRFPI) controller to regulate the instantaneous output voltage, a capacitor current shaping loop in the stationary reference frame to provide active...... in the synchronous reference frame, it is not straightforward to fine-tune the control parameters and evaluate the stability of the whole closed loop system. To overcome this problem, the stationary reference frame equivalent of the voltage loop is derived. Then, a step-by-step systematic design procedure based...

  20. Consistent Feature Extraction From Vector Fields: Combinatorial Representations and Analysis Under Local Reference Frames

    Energy Technology Data Exchange (ETDEWEB)

    Bhatia, Harsh [Univ. of Utah, Salt Lake City, UT (United States)

    2015-05-01

    This dissertation presents research on addressing some of the contemporary challenges in the analysis of vector fields—an important type of scientific data useful for representing a multitude of physical phenomena, such as wind flow and ocean currents. In particular, new theories and computational frameworks to enable consistent feature extraction from vector fields are presented. One of the most fundamental challenges in the analysis of vector fields is that their features are defined with respect to reference frames. Unfortunately, there is no single “correct” reference frame for analysis, and an unsuitable frame may cause features of interest to remain undetected, thus creating serious physical consequences. This work develops new reference frames that enable extraction of localized features that other techniques and frames fail to detect. As a result, these reference frames objectify the notion of “correctness” of features for certain goals by revealing the phenomena of importance from the underlying data. An important consequence of using these local frames is that the analysis of unsteady (time-varying) vector fields can be reduced to the analysis of sequences of steady (timeindependent) vector fields, which can be performed using simpler and scalable techniques that allow better data management by accessing the data on a per-time-step basis. Nevertheless, the state-of-the-art analysis of steady vector fields is not robust, as most techniques are numerical in nature. The residing numerical errors can violate consistency with the underlying theory by breaching important fundamental laws, which may lead to serious physical consequences. This dissertation considers consistency as the most fundamental characteristic of computational analysis that must always be preserved, and presents a new discrete theory that uses combinatorial representations and algorithms to provide consistency guarantees during vector field analysis along with the uncertainty

  1. Reference-Frame-Independent and Measurement-Device-Independent Quantum Key Distribution Using One Single Source

    Science.gov (United States)

    Li, Qian; Zhu, Changhua; Ma, Shuquan; Wei, Kejin; Pei, Changxing

    2018-04-01

    Measurement-device-independent quantum key distribution (MDI-QKD) is immune to all detector side-channel attacks. However, practical implementations of MDI-QKD, which require two-photon interferences from separated independent single-photon sources and a nontrivial reference alignment procedure, are still challenging with current technologies. Here, we propose a scheme that significantly reduces the experimental complexity of two-photon interferences and eliminates reference frame alignment by the combination of plug-and-play and reference frame independent MDI-QKD. Simulation results show that the secure communication distance can be up to 219 km in the finite-data case and the scheme has good potential for practical MDI-QKD systems.

  2. On Celestial Wings,

    Science.gov (United States)

    1995-11-01

    the long night of seeking out stars, taking celestial fixes and plotting them on his chart . Sometimes the stars would have been elusive and would seem...toward the island of Oahu and his pilot, Ted S. Faulkner, prepared for landing at Hickam Field. Louis hurriedly folded his navigational charts and packed...by any chance receive any of the packages I sent? I hope that you like the candlesticks , Mother. There is quite a story behind them that I will tell

  3. DQ reference frame modeling and control of single-phase active power decoupling circuits

    DEFF Research Database (Denmark)

    Tang, Yi; Qin, Zian; Blaabjerg, Frede

    2015-01-01

    Power decoupling circuits can compensate the inherent double line frequency ripple power in single-phase systems and greatly facilitate their dc-link capacitor design. Example applications of power decoupling circuit include photovoltaic, light-emitting diode, fuel cell, and motor drive systems....... This paper presents the dq synchronous reference frame modeling of single-phase power decoupling circuits and a complete model describing the dynamics of dc-link ripple voltage is presented. The proposed model is universal and valid for both inductive and capacitive decoupling circuits, and the input...... of decoupling circuits can be either dependent or independent of its front-end converters. Based on this model, a dq synchronous reference frame controller is designed which allows the decoupling circuit to operate in two different modes because of the circuit symmetry. Simulation and experimental results...

  4. The perspective matters! Multisensory integration in ego-centric reference frames determines full body ownership

    Directory of Open Access Journals (Sweden)

    Valeria Ivanova Petkova

    2011-03-01

    Full Text Available Recent advances in experimental science have made it possible to investigate the perceptual processes involved in generating a sense of owning an entire body. This is achieved by full-body ownership illusions which make use of specific patterns of visual and somatic stimuli integration. Here we investigate the fundamental question of the reference frames used in the process of attributing an entire body to the self. We quantified the strength of the body-swap illusion in conditions where the participants were observing this artificial body from the perspective of the first or third person. Consistent results from subjective reports and physiological recordings show that the first person visual perspective is critical for the induction of this full-body ownership illusion. This demonstrates that the multisensory integration processes producing the sense of corporeal self operates in an ego-centric reference frame.

  5. The Perspective Matters! Multisensory Integration in Ego-Centric Reference Frames Determines Full-Body Ownership

    Science.gov (United States)

    Petkova, Valeria I.; Khoshnevis, Mehrnoush; Ehrsson, H. Henrik

    2011-01-01

    Recent advances in experimental science have made it possible to investigate the perceptual processes involved in generating a sense of owning an entire body. This is achieved by full-body ownership illusions which make use of specific patterns of visual and somatic stimuli integration. Here we investigate the fundamental question of the reference frames used in the process of attributing an entire body to the self. We quantified the strength of the body-swap illusion in conditions where the participants were observing this artificial body from the perspective of the first or third person. Consistent results from subjective reports and physiological recordings show that the first person visual perspective is critical for the induction of this full-body ownership illusion. This demonstrates that the multisensory integration processes producing the sense of corporeal self operates in an ego-centric reference frame. PMID:21687436

  6. Frames of Reference: A Metaphor for Analyzing and Interpreting Attitudes of Environmental Policy Makers and Policy Influencers

    Science.gov (United States)

    Swaffield

    1998-07-01

    / The concept of frame of reference offers a potentially useful analytical metaphor in environmental management. This is illustrated by a case study in which attitudes of individuals involved in the management of trees in the New Zealand high country are classified into seven distinctive frames of reference. Some practical and theoretical implications of the use of the frame metaphor are explored, including its potential contribution to the emerg- ing field of communicative planning. KEY WORDS: Frames of reference; Environmental policy analysis; Metaphor; New Zealand high country

  7. Extension of the PSE code NOLOT for transition analysis in rotating reference frames

    OpenAIRE

    Dechamps, Xavier; Hein, Stefan

    2016-01-01

    The present work aims at contributing to a better understanding of the effect of rotation on the stability properties of boundary layers. For this purpose, the Parabolized-Stability-Equations based NOLOT code was extended to rotating reference frames through the inclusion of the centrifugal and Coriolis forces. Stability analyses of three flow configurations were then considered for verification: the rotating Blasius Profile, the flow along a curved wall and the three-dimensional flow due to ...

  8. RETRACTED: Quantum key distribution without sharing reference frame using single photon rotational-invariant subspace

    Science.gov (United States)

    Chen, Dong-Xu; Liu, Rui-Feng; Zhang, Pei; Li, Hong-Rong; Gao, Hong; Li, Fu-Li

    2013-11-01

    We report an experimental proposal of quantum key distribution without sharing reference frame by using single photon rotational-invariant subspace. The rotational-invariant subspace is achieved by taking advantage of photon's spin-orbital composite states. Our scheme is simple and can be developed as a compact QKD system under current technology. Earth-to-satellite QKD is an emerging scenario that will benefit from our protocol.

  9. From a Somatotopic to a Spatiotopic Frame of Reference for the Localization of Nociceptive Stimuli.

    Directory of Open Access Journals (Sweden)

    Annick L De Paepe

    Full Text Available To react efficiently to potentially threatening stimuli, we have to be able to localize these stimuli in space. In daily life we are constantly moving so that our limbs can be positioned at the opposite side of space. Therefore, a somatotopic frame of reference is insufficient to localize nociceptive stimuli. Here we investigated whether nociceptive stimuli are mapped into a spatiotopic frame of reference, and more specifically a peripersonal frame of reference, which takes into account the position of the body limbs in external space, as well as the occurrence of external objects presented near the body. Two temporal order judgment (TOJ experiments were conducted, during which participants had to decide which of two nociceptive stimuli, one applied to either hand, had been presented first while their hands were either uncrossed or crossed over the body midline. The occurrence of the nociceptive stimuli was cued by uninformative visual cues. We found that the visual cues prioritized the perception of nociceptive stimuli applied to the hand laying in the cued side of space, irrespective of posture. Moreover, the influence of the cues was smaller when they were presented far in front of participants' hands as compared to when they were presented in close proximity. Finally, participants' temporal sensitivity was reduced by changing posture. These findings are compatible with the existence of a peripersonal frame of reference for the localization of nociceptive stimuli. This allows for the construction of a stable representation of our body and the space closely surrounding our body, enabling a quick and efficient reaction to potential physical threats.

  10. From a Somatotopic to a Spatiotopic Frame of Reference for the Localization of Nociceptive Stimuli.

    Science.gov (United States)

    De Paepe, Annick L; Crombez, Geert; Legrain, Valéry

    2015-01-01

    To react efficiently to potentially threatening stimuli, we have to be able to localize these stimuli in space. In daily life we are constantly moving so that our limbs can be positioned at the opposite side of space. Therefore, a somatotopic frame of reference is insufficient to localize nociceptive stimuli. Here we investigated whether nociceptive stimuli are mapped into a spatiotopic frame of reference, and more specifically a peripersonal frame of reference, which takes into account the position of the body limbs in external space, as well as the occurrence of external objects presented near the body. Two temporal order judgment (TOJ) experiments were conducted, during which participants had to decide which of two nociceptive stimuli, one applied to either hand, had been presented first while their hands were either uncrossed or crossed over the body midline. The occurrence of the nociceptive stimuli was cued by uninformative visual cues. We found that the visual cues prioritized the perception of nociceptive stimuli applied to the hand laying in the cued side of space, irrespective of posture. Moreover, the influence of the cues was smaller when they were presented far in front of participants' hands as compared to when they were presented in close proximity. Finally, participants' temporal sensitivity was reduced by changing posture. These findings are compatible with the existence of a peripersonal frame of reference for the localization of nociceptive stimuli. This allows for the construction of a stable representation of our body and the space closely surrounding our body, enabling a quick and efficient reaction to potential physical threats.

  11. Legal Innovation in European Contract Law: Within and Beyond the (Draft) Common Frame of Reference

    OpenAIRE

    MÖSLEIN, Florian

    2009-01-01

    The Europeanization of contract law has continuously developed over the past 25 years. It is now at a defining stage, with the Draft Common Frame of Reference (DCFR) recently being published. This article is not primarily concerned with the substance of this instrument, but with the process of legal innovation it might trigger. The hypothesis is that the adoption of such a rulebook will have a significant impact on the future development of European contract law. Yet the nature and likely eff...

  12. Application of the Undifferenced GNSS Precise Positioning in Determining Coordinates in National Reference Frames

    Science.gov (United States)

    Krzan, Grzegorz; Stępniak, Katarzyna

    2017-09-01

    In high-accuracy positioning using GNSS, the most common solution is still relative positioning using double-difference observations of dual-frequency measurements. An increasingly popular alternative to relative positioning are undifferenced approaches, which are designed to make full use of modern satellite systems and signals. Positions referenced to global International Terrestrial Reference Frame (ITRF2008) obtained from Precise Point Positioning (PPP) or Undifferenced (UD) network solutions have to be transformed to national (regional) reference frame, which introduces additional bases related to the transformation process. In this paper, satellite observations from two test networks using different observation time series were processed. The first test concerns the positioning accuracy from processing one year of dual-frequency GPS observations from 14 EUREF Permanent Network (EPN) stations using NAPEOS 3.3.1 software. The results were transformed into a national reference frame (PL-ETRF2000) and compared to positions from an EPN cumulative solution, which was adopted as the true coordinates. Daily observations were processed using PPP and UD multi-station solutions to determine the final accuracy resulting from satellite positioning, the transformation to national coordinate systems and Eurasian intraplate plate velocities. The second numerical test involved similar processing strategies of post-processing carried out using different observation time series (30 min., 1 hour, 2 hours, daily) and different classes of GNSS receivers. The centimeter accuracy of results presented in the national coordinate system satisfies the requirements of many surveying and engineering applications.

  13. Different effects of numerical magnitude on visual and proprioceptive reference frames

    Directory of Open Access Journals (Sweden)

    Elvio eBlini

    2013-04-01

    Full Text Available This study assessed whether numerical magnitude affects the setting of basic spatial coordinates and reference frames, namely the subjective straight ahead. Three tasks were given to 24 right-handed healthy participants: a proprioceptive and a visuo-proprioceptive task, requiring pointing to the subjective straight ahead, and a visual task, requiring a perceptual judgment about the straight ahead position of a light moving left-to-right, or right-to-left. A control task, requiring the bisection of rods of different lengths, was also given. The four tasks were performed under conditions of passive auditory numerical (i.e., listening to small, 2, and large, 8, numbers, and neutral auditory-verbal (blah stimulation. Numerical magnitude modulates the participants’ deviations in the visual straight ahead task, when the movement of the light is from left to right, with the small number bringing about a leftward deviation, the large number a rightward deviation. This result suggests that the spatial effects induced by the activation of the mental number line extend to an egocentric frame of reference. A similar directional modulation was found in the rod bisection task, in line with previous evidence. No effects of numerical magnitude were found on the proprioceptive and visuo-proprioceptive straight ahead tasks. These results suggest that the spatial effects induced by the activation of the mental number line extend to an egocentric frame of reference but only when a portion of horizontal space has to be actively explored.

  14. Modality-switching in the Simon task: The clash of reference frames.

    Science.gov (United States)

    Ruzzoli, Manuela; Soto-Faraco, Salvador

    2017-10-01

    The representation of spatial information related to an event can influence behavior even when location is task-irrelevant, as in the case of Stimulus-Response (S-R) compatibility effects on the Simon task. However, unlike single-modality situations, which are often used to study the Simon effect, in real-life scenarios various sensory modalities provide spatial information coded in different coordinate systems. Here, we address the expression of S-R compatibility effects in mixed-modality contexts, where events can occur in 1 of various sensory modalities (i.e., vision, touch or audition). The results confirm that, in single-modality cases, Simon effects in vision are expressed in an external spatial frame of reference, while touch information is coded anatomically. Remarkably, when mixing visual and tactile trials in an unpredictable way, the Simon effect disappeared in vision whereas tactile Simon effects remained expressed in their own (anatomical) frame of reference. Mixing visual and auditory stimuli did not obliterate the visual Simon effect and S-R compatibility effects in an external reference frame were evident for both modalities. The extinction of visual Simon effects as a result of mixing visual and tactile modalities can be interpreted as a consequence of the dynamic reorganization of the weights associated to the different sources of spatial information at play. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  15. Early visual deprivation prompts the use of body-centered frames of reference for auditory localization.

    Science.gov (United States)

    Vercillo, Tiziana; Tonelli, Alessia; Gori, Monica

    2018-01-01

    The effects of early visual deprivation on auditory spatial processing are controversial. Results from recent psychophysical studies show that people who were born blind have a spatial impairment in localizing sound sources within specific auditory settings, while previous psychophysical studies revealed enhanced auditory spatial abilities in early blind compared to sighted individuals. An explanation of why an auditory spatial deficit is sometimes observed within blind populations and its task-dependency remains to be clarified. We investigated auditory spatial perception in early blind adults and demonstrated that the deficit derives from blind individual's reduced ability to remap sound locations using an external frame of reference. We found that performance in blind population was severely impaired when they were required to localize brief auditory stimuli with respect to external acoustic landmarks (external reference frame) or when they had to reproduce the spatial distance between two sounds. However, they performed similarly to sighted controls when had to localize sounds with respect to their own hand (body-centered reference frame), or to judge the distances of sounds from their finger. These results suggest that early visual deprivation and the lack of visual contextual cues during the critical period induce a preference for body-centered over external spatial auditory representations. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. The Multi-Disciplinary Graduate Program in Educational Research. Final Report, Part V; The Frame of Reference Study.

    Science.gov (United States)

    Lazarsfeld, Paul F., Ed.

    This "Frame of Reference Study" consists of the fifth section of the final report of the Multi-Disciplinary Graduate Program in Educational Research of the University of Pittsburgh. The term, "frames of reference," is used to mean the context of assumptions, procedures, rules, cognitive models, and conceptions of the nature of…

  17. Fault Ride-through Capability Implementation in Wind Turbine Converters Using a Decoupled Double Synchronous Reference Frame PLL

    DEFF Research Database (Denmark)

    Rodriguez, Pedro; Alloza, Alvaro Luna; Teodorescu, Remus

    2007-01-01

    This work exploits the Decoupled Double Synchronous Reference Frame PLL (DDSRF-PLL) as an effective method for grid synchronization of WT's power converters in the presence of transient faults in the grid. The DDSRF-PLL uses a dual synchronous reference frame and a decoupling network to effective...

  18. Grid Synchronization of Wind Turbine Converters under Transient Grid Faults using a Double Synchronous Reference Frame PLL

    DEFF Research Database (Denmark)

    Teodorescu, Remus; Blaabjerg, Frede; Rodriguez, P.

    2008-01-01

    This work employs the Double Synchronous Reference Frame PLL (DSRF-PLL) as an effective method for grid synchronization of WT's power converters in the presence of transient faults in the grid. The DSRF-PLL exploits a dual synchronous reference frame voltage characterization, adding a decoupling ...

  19. Rate of alignment and communication using quantum systems in the absence of a shared frame of reference

    Science.gov (United States)

    Skotiniotis, Michael

    Quantum information theory is concerned with the storage, transmission, and manipulation of information that is represented in the degrees of freedom of quantum systems. These degrees of freedom are described relative to an external frame of reference. The lack of a requisite frame of reference imposes restrictions on the types of states quantum systems can be prepared in and the type of operations that can be performed on quantum systems. This thesis is concerned with the communication between two parties that lack a shared frame of reference. Specifically, I introduce a protocol whereby the parties can align their respective frames of reference, and a protocol for communicating quantum information in a reference frame independent manner. Using the accessible information to quantify the success of a reference frame alignment protocol I propose a new measure—the alignment rate—for quantifying the ability of a quantum state to stand in place of a classical frame of reference. I show that for the case where Alice and Bob lack a shared frame of reference associated with the groups G = U(1) and G = ZM (the finite cyclic group of M elements), the alignment rate is equal to the regularized, linearized G-asymmetry. The latter is a unique measure of the frameness of a quantum state and my result provides an operational interpretation of the G-asymmetry that was thus far lacking. In addition, I show that the alignment rate for finite cyclic groups of more than three elements is super-additive under the tensor product of two distinct pure quantum states. The latter is, to my knowledge, the first instance of a regularized quantity that exhibits super-additivity. In addition, I propose a reference-frame-independent protocol for communicating quantum information in the absence of a shared frame of reference associated with a general finite group G. The protocol transmits m logical qudits using r + m physical qudits prepared in a specific state that is reference-frame

  20. Adventures in Celestial Mechanics

    CERN Document Server

    Szebehely, Victor G

    1998-01-01

    A fascinating introduction to the basic principles of orbital mechanics. It has been three hundred years since Isaac Newton first formulated laws to explain the orbits of the Moon and the planets of our solar system. In so doing he laid the groundwork for modern science's understanding of the workings of the cosmos and helped pave the way to the age of space exploration. Adventures in Celestial Mechanics offers students an enjoyable way to become acquainted with the basic principles involved in the motions of natural and human-made bodies in space. Packed with examples in which these principle

  1. The Simon effect based on the egocentric and allocentric reference frame.

    Science.gov (United States)

    Wang, Huan; Liu, Nan; Zou, Guiying; Li, Hui; Zeng, Hang; Chen, Jiedan; Chen, Qi

    2016-02-01

    The classic Simon effect refers to the phenomenon that responses are faster when the task-irrelevant egocentric stimulus location is on the same side as the response hand than when not. However, the spatial location of an object often varies according to which reference frame the object location was represented in, e.g., egocentric versus allocentric reference frame. It has been unknown, however, whether and how the Simon effect based on the egocentric and the allocentric reference interact, and whether the potential interaction between them is affected by task demands. To investigate these questions, we orthogonally crossed the stimulus-response compatibility induced by the egocentric and the allocentric positions during the Simon effect. Moreover, the irrelevant egocentric and allocentric positions were either explicitly represented via interleaving spatial and non-spatial tasks in Experiment 1 or not in Experiment 2. The results suggested that the Simon effect based on the egocentric locations occurred irrespective of whether the egocentric representations were explicitly coded based on current task demands or not. The Simon effect based on allocentric locations, however, seemed to occur only when the allocentric representations were explicitly induced. Moreover, the egocentric and allocentric Simon effect interacted in a similar way irrespective of task demands, with significantly delayed responses when both the egocentric and the allocentric locations were incongruent with the response code.

  2. Frontiers in relativistic celestial mechanics

    CERN Document Server

    2014-01-01

    Relativistic celestial mechanics – investigating the motion celestial bodies under the influence of general relativity – is a major tool of modern experimental gravitational physics. With a wide range of prominent authors from the field, this two-volume series consists of reviews on a multitude of advanced topics in the area of relativistic celestial mechanics – starting from more classical topics such as the regime of asymptotically-flat spacetime, light propagation and celestial ephemerides, but also including its role in cosmology and alternative theories of gravity as well as modern experiments in this area.

  3. Frontal eye fields involved in shifting frame of reference within working memory for scenes

    DEFF Research Database (Denmark)

    Wallentin, Mikkel; Roepstorff, Andreas; Burgess, Neil

    2008-01-01

    Working memory (WM) evoked by linguistic cues for allocentric spatial and egocentric spatial aspects of a visual scene was investigated by correlating fMRI BOLD signal (or "activation") with performance on a spatial-relations task. Subjects indicated the relative positions of a person or object...... during shifting reference frames in representational space. Analysis of actual eye movements in 3 subjects revealed no difference between egocentric and allocentric recall tasks where visual stimuli were also absent. Thus, the FEF machinery for directing eye movements may also be involved in changing...

  4. W production at LHC: lepton angular distributions and reference frames for probing hard QCD

    Energy Technology Data Exchange (ETDEWEB)

    Richter-Was, E. [Jagiellonian University, Institute of Physics, Krakow (Poland); Was, Z. [Institute of Nuclear Physics Polish Academy of Sciences, Krakow (Poland)

    2017-02-15

    Precision tests of the Standard Model in the Strong and Electroweak sectors play a crucial role, among the physics program of LHC experiments. Because of the nature of proton-proton processes, observables based on the measurement of the direction and energy of final state leptons provide the most precise probes of such processes. In the present paper, we concentrate on the angular distribution of leptons from W → lν decays in the lepton-pair rest-frame. The vector nature of the intermediate state imposes that distributions are to a good precision described by spherical harmonics of at most second order. We argue, that contrary to general belief often expressed in the literature, the full set of angular coefficients can be measured experimentally, despite the presence of escaping detection neutrino in the final state. There is thus no principle difference with respect to the phenomenology of the Z/γ → l{sup +}l{sup -} Drell-Yan process. We show also, that with the proper choice of the reference frames, only one coefficient in this polynomial decomposition remains sizable, even in the presence of one or more high p{sub T} jets. The necessary stochastic choice of the frames relies on probabilities independent from any coupling constants. In this way, electroweak effects (dominated by the V - A nature of W couplings to fermions), can be better separated from the ones of strong interactions. The separation is convenient for the measurements interpretation. (orig.)

  5. Unit Template Synchronous Reference Frame Theory Based Control Algorithm for DSTATCOM

    Science.gov (United States)

    Bangarraju, J.; Rajagopal, V.; Jayalaxmi, A.

    2014-04-01

    This article proposes new and simplified unit templates instead of standard phase locked loop (PLL) for Synchronous Reference Frame Theory Control Algorithm (SRFT). The extraction of synchronizing components (sinθ and cosθ) for parks and inverse parks transformation using standard PLL takes more execution time. This execution time in control algorithm delays the extraction of reference source current generation. The standard PLL not only takes more execution time but also increases the reactive power burden on the Distributed Static Compensator (DSTATCOM). This work proposes a unit template based SRFT control algorithm for four-leg insulated gate bipolar transistor based voltage source converter for DSTATCOM in distribution systems. This will reduce the execution time and reactive power burden on the DSTATCOM. The proposed DSTATCOM suppress harmonics, regulates the terminal voltage along with neutral current compensation. The DSTATCOM in distribution systems with proposed control algorithm is modeled and simulated using MATLAB using SIMULINK and Simpower systems toolboxes.

  6. Out of body, out of space: Impaired reference frame processing in eating disorders.

    Science.gov (United States)

    Serino, Silvia; Dakanalis, Antonios; Gaudio, Santino; Carrà, Giuseppe; Cipresso, Pietro; Clerici, Massimo; Riva, Giuseppe

    2015-12-15

    A distorted body representation is a core symptom in eating disorders (EDs), though its mechanism is unclear. Allocentric lock theory, emphasising the role of reference frame processing in body image, suggests that ED patients may be (b)locked to an (allocentric) representation of their own body stored in long-term memory (e.g., my body is fat) that is not updated (modified) by the (real-time egocentric) perception-driven experience of the physical body. Employing a well-validated virtual reality-based procedure, relative to healthy controls, ED patients showed deficits in the ability to refer to and update a long-term stored (allocentric) representation with (egocentric) perceptual-driven inputs. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  7. Future global SLR network evolution and its impact on the terrestrial reference frame

    Science.gov (United States)

    Kehm, Alexander; Bloßfeld, Mathis; Pavlis, Erricos C.; Seitz, Florian

    2017-11-01

    Satellite laser ranging (SLR) is an important technique that contributes to the determination of terrestrial geodetic reference frames, especially to the realization of the origin and the scale of global networks. One of the major limiting factors of SLR-derived reference frame realizations is the datum accuracy which significantly suffers from the current global SLR station distribution. In this paper, the impact of a potential future development of the SLR network on the estimated datum parameters is investigated. The current status of the SLR network is compared to a simulated potential future network featuring additional stations improving the global network geometry. In addition, possible technical advancements resulting in a higher amount of observations are taken into account as well. As a result, we find that the network improvement causes a decrease in the scatter of the network translation parameters of up to 24%, and up to 20% for the scale, whereas the technological improvement causes a reduction in the scatter of up to 27% for the translations and up to 49% for the scale. The Earth orientation parameters benefit by up to 15% from both effects.

  8. Fronto-Parietal Brain Responses to Visuotactile Congruence in an Anatomical Reference Frame

    Directory of Open Access Journals (Sweden)

    Jakub Limanowski

    2018-03-01

    Full Text Available Spatially and temporally congruent visuotactile stimulation of a fake hand together with one’s real hand may result in an illusory self-attribution of the fake hand. Although this illusion relies on a representation of the two touched body parts in external space, there is tentative evidence that, for the illusion to occur, the seen and felt touches also need to be congruent in an anatomical reference frame. We used functional magnetic resonance imaging and a somatotopical, virtual reality-based setup to isolate the neuronal basis of such a comparison. Participants’ index or little finger was synchronously touched with the index or little finger of a virtual hand, under congruent or incongruent orientations of the real and virtual hands. The left ventral premotor cortex responded significantly more strongly to visuotactile co-stimulation of the same versus different fingers of the virtual and real hand. Conversely, the left anterior intraparietal sulcus responded significantly more strongly to co-stimulation of different versus same fingers. Both responses were independent of hand orientation congruence and of spatial congruence of the visuotactile stimuli. Our results suggest that fronto-parietal areas previously associated with multisensory processing within peripersonal space and with tactile remapping evaluate the congruence of visuotactile stimulation on the body according to an anatomical reference frame.

  9. Adaptive Interval Type-2 Fuzzy Logic Control for PMSM Drives with a Modified Reference Frame

    KAUST Repository

    Chaoui, Hicham

    2017-01-10

    In this paper, an adaptive interval type-2 fuzzy logic control scheme is proposed for high-performance permanent magnet synchronous machine drives. This strategy combines the power of type-2 fuzzy logic systems with the adaptive control theory to achieve accurate tracking and robustness to higher uncertainties. Unlike other controllers, the proposed strategy does not require electrical transducers and hence, no explicit currents loop regulation is needed, which yields a simplified control scheme. But, this limits the machine\\'s operation range since it results in a higher energy consumption. Therefore, a modified reference frame is also proposed in this paper to decrease the machine\\'s consumption. To better assess the performance of the new reference frame, comparison against its original counterpart is carried-out under the same conditions. Moreover, the stability of the closed-loop control scheme is guaranteed by a Lyapunov theorem. Simulation and experimental results for numerous situations highlight the effectiveness of the proposed controller in standstill, transient, and steady-state conditions.

  10. Lost in space: multisensory conflict yields adaptation in spatial representations across frames of reference.

    Science.gov (United States)

    Lohmann, Johannes; Butz, Martin V

    2017-08-01

    According to embodied cognition, bodily interactions with our environment shape the perception and representation of our body and the surrounding space, that is, peripersonal space. To investigate the adaptive nature of these spatial representations, we introduced a multisensory conflict between vision and proprioception in an immersive virtual reality. During individual bimanual interaction trials, we gradually shifted the visual hand representation. As a result, participants unknowingly shifted their actual hands to compensate for the visual shift. We then measured the adaptation to the invoked multisensory conflict by means of a self-localization and an external localization task. While effects of the conflict were observed in both tasks, the effects systematically interacted with the type of localization task and the available visual information while performing the localization task (i.e., the visibility of the virtual hands). The results imply that the localization of one's own hands is based on a multisensory integration process, which is modulated by the saliency of the currently most relevant sensory modality and the involved frame of reference. Moreover, the results suggest that our brain strives for consistency between its body and spatial estimates, thereby adapting multiple, related frames of reference, and the spatial estimates within, due to a sensory conflict in one of them.

  11. Separability and Entanglement in the Hilbert Space Reference Frames Related Through the Generic Unitary Transform for Four Level System

    Science.gov (United States)

    Man'ko, V. I.; Markovich, L. A.

    2018-02-01

    Quantum correlations in the state of four-level atom are investigated by using generic unitary transforms of the classical (diagonal) density matrix. Partial cases of pure state, X-state, Werner state are studied in details. The geometrical meaning of unitary Hilbert reference-frame rotations generating entanglement in the initially separable state is discussed. Characteristics of the entanglement in terms of concurrence, entropy and negativity are obtained as functions of the unitary matrix rotating the reference frame.

  12. Celestial data routing network

    Science.gov (United States)

    Bordetsky, Alex

    2000-11-01

    Imagine that information processing human-machine network is threatened in a particular part of the world. Suppose that an anticipated threat of physical attacks could lead to disruption of telecommunications network management infrastructure and access capabilities for small geographically distributed groups engaged in collaborative operations. Suppose that small group of astronauts are exploring the solar planet and need to quickly configure orbital information network to support their collaborative work and local communications. The critical need in both scenarios would be a set of low-cost means of small team celestial networking. To the geographically distributed mobile collaborating groups such means would allow to maintain collaborative multipoint work, set up orbital local area network, and provide orbital intranet communications. This would be accomplished by dynamically assembling the network enabling infrastructure of the small satellite based router, satellite based Codec, and set of satellite based intelligent management agents. Cooperating single function pico satellites, acting as agents and personal switching devices together would represent self-organizing intelligent orbital network of cooperating mobile management nodes. Cooperative behavior of the pico satellite based agents would be achieved by comprising a small orbital artificial neural network capable of learning and restructing the networking resources in response to the anticipated threat.

  13. A Novel Real-Time Reference Key Frame Scan Matching Method.

    Science.gov (United States)

    Mohamed, Haytham; Moussa, Adel; Elhabiby, Mohamed; El-Sheimy, Naser; Sesay, Abu

    2017-05-07

    Unmanned aerial vehicles represent an effective technology for indoor search and rescue operations. Typically, most indoor missions' environments would be unknown, unstructured, and/or dynamic. Navigation of UAVs in such environments is addressed by simultaneous localization and mapping approach using either local or global approaches. Both approaches suffer from accumulated errors and high processing time due to the iterative nature of the scan matching method. Moreover, point-to-point scan matching is prone to outlier association processes. This paper proposes a low-cost novel method for 2D real-time scan matching based on a reference key frame (RKF). RKF is a hybrid scan matching technique comprised of feature-to-feature and point-to-point approaches. This algorithm aims at mitigating errors accumulation using the key frame technique, which is inspired from video streaming broadcast process. The algorithm depends on the iterative closest point algorithm during the lack of linear features which is typically exhibited in unstructured environments. The algorithm switches back to the RKF once linear features are detected. To validate and evaluate the algorithm, the mapping performance and time consumption are compared with various algorithms in static and dynamic environments. The performance of the algorithm exhibits promising navigational, mapping results and very short computational time, that indicates the potential use of the new algorithm with real-time systems.

  14. An introduction to celestial mechanics

    CERN Document Server

    Moulton, Forest Ray

    1984-01-01

    An unrivaled text in the field of celestial mechanics, Moulton's theoretical work on the prediction and interpretation of celestial phenomena has not been superseded. By providing a general account of all parts of celestial mechanics without an over-full treatment of any single aspect, by stating all the problems in advance, and, where the transformations are long, giving an outline of the steps which must be made, and by noting all the places where assumptions have been introduced or unjustified methods employed, Moulton has insured that his work will be valuable to all who are interested in

  15. Moving loads on flexible structures presented in the floating frame of reference formulation

    Energy Technology Data Exchange (ETDEWEB)

    Hartweg, Stefan, E-mail: stefan.hartweg@web.de; Heckmann, Andreas, E-mail: andreas.heckmann@dlr.de [German Aerospace Center (DLR), Institute of System Dynamics and Control (Germany)

    2016-06-15

    The introduction of moving loads in the Floating Frame of Reference Formulation is presented. We derive the kinematics and governing equations of motion of a general flexible multibody system and their extension to moving loads. The equivalence of convective effects with Coriolis and centripetal forces is shown. These effects are measured numerically and their significance in moving loads traveling at high speed is confirmed. A method is presented to handle discontinuities when moving loads separate from the flexible structure. The method is extended from beam models to general flexible structures obtained by means of the Finite Element Method. An interpolation method for the deformation field of the modal representation of these bodies is introduced.The work is concluded by application of the method to modern mechanical problems in numerical simulations.

  16. Demonstration of free-space reference frame independent quantum key distribution

    International Nuclear Information System (INIS)

    Wabnig, J; Bitauld, D; Li, H W; Niskanen, A O; Laing, A; O'Brien, J L

    2013-01-01

    Quantum key distribution (QKD) is moving from research laboratories towards applications. As computing becomes more mobile, cashless as well as cardless payment solutions are introduced. A possible route to increase the security of wireless communications is to incorporate QKD in a mobile device. Handheld devices present a particular challenge as the orientation and the phase of a qubit will depend on device motion. This problem is addressed by the reference frame independent (RFI) QKD scheme. The scheme tolerates an unknown phase between logical states that vary slowly compared to the rate of particle repetition. Here we experimentally demonstrate the feasibility of RFI QKD over a free-space link in a prepare and measure scheme using polarization encoding. We extend the security analysis of the RFI QKD scheme to be able to deal with uncalibrated devices and a finite number of measurements. Together these advances are an important step towards mass production of handheld QKD devices. (paper)

  17. Moving loads on flexible structures presented in the floating frame of reference formulation

    International Nuclear Information System (INIS)

    Hartweg, Stefan; Heckmann, Andreas

    2016-01-01

    The introduction of moving loads in the Floating Frame of Reference Formulation is presented. We derive the kinematics and governing equations of motion of a general flexible multibody system and their extension to moving loads. The equivalence of convective effects with Coriolis and centripetal forces is shown. These effects are measured numerically and their significance in moving loads traveling at high speed is confirmed. A method is presented to handle discontinuities when moving loads separate from the flexible structure. The method is extended from beam models to general flexible structures obtained by means of the Finite Element Method. An interpolation method for the deformation field of the modal representation of these bodies is introduced.The work is concluded by application of the method to modern mechanical problems in numerical simulations.

  18. An alternative frame of reference for rehabilitation: the helping process versus the medical model.

    Science.gov (United States)

    Anderson, T P

    1975-03-01

    In rehabilitation the frame of reference of the helping professions is significantly different from the standard medical model in the following areas: the dynamics of the relationship, basis for client's trust of the professional, activity versus passivity of both the client and the professional, and the approach to identification and solution of client problems. "The helping process" as practiced in the helping professions is not doing the task, but assisting the client to do it himself, for himself. In this process the needs, values and feelings of both the helper and the helpee must be recognized and dealt with. For the helping process to be successful, three basic conditions are required: development of mutual trust, joint exploration of the problem(s) and listening by both sides. Also involved in attaining success in the helping process is an awareness of not only the barriers in receiving help but also the difficulties in giving help.

  19. Deep mantle structure as a reference frame for movements in and on the Earth.

    Science.gov (United States)

    Torsvik, Trond H; van der Voo, Rob; Doubrovine, Pavel V; Burke, Kevin; Steinberger, Bernhard; Ashwal, Lewis D; Trønnes, Reidar G; Webb, Susan J; Bull, Abigail L

    2014-06-17

    Earth's residual geoid is dominated by a degree-2 mode, with elevated regions above large low shear-wave velocity provinces on the core-mantle boundary beneath Africa and the Pacific. The edges of these deep mantle bodies, when projected radially to the Earth's surface, correlate with the reconstructed positions of large igneous provinces and kimberlites since Pangea formed about 320 million years ago. Using this surface-to-core-mantle boundary correlation to locate continents in longitude and a novel iterative approach for defining a paleomagnetic reference frame corrected for true polar wander, we have developed a model for absolute plate motion back to earliest Paleozoic time (540 Ma). For the Paleozoic, we have identified six phases of slow, oscillatory true polar wander during which the Earth's axis of minimum moment of inertia was similar to that of Mesozoic times. The rates of Paleozoic true polar wander (Earth's mantle may have operated throughout the entire Phanerozoic.

  20. Simulation and Hardware Implementation of Shunt Active Power Filter Based on Synchronous Reference Frame Theory

    Directory of Open Access Journals (Sweden)

    Karthikrjan Senthilnathan

    2018-02-01

    Full Text Available This paper describes about the Hybrid Shunt Active Power Filter (HSAPF for the elimination of the current harmonics in the line side of the three phase three wire systems. The Active Power Filter is based on the Voltage Source Converter (VSC topology. The control strategy for the converter is based on Synchronous Reference Frame (SRF theory. The compensation of harmonics is done by the APF which is connected in the shunt configuration to the system. The Shunt APF has the better compensation of current harmonics. The design and implementation of Shunt active power filter is done by MATLAB/Simulink. The real time implementation by using the ATMEGA 8 Microcontroller. The Simulation and Hardware results shows that the current harmonics are eliminated in the system

  1. Impact of Glacial Isostatic Adjustment on North America Plate Specific Terrestrial Reference Frame

    Science.gov (United States)

    Herring, Thomas; Melbourne, Tim; Murray, Mark; Floyd, Mike; Szeliga, Walter; King, Robert; Phillips, David; Puskas, Christine

    2017-04-01

    We examine the impact of incorporating glacial isostatic adjustment (GIA) models in determining the Euler poles for plate specific terrestrial reference frames. We will specifically examine the impact of GIA models on the realization of a North America Reference frame. We use a combination of the velocity fields determined by the Geodesy Advancing Geosciences and EarthScope (GAGE) Facility which analyzes GPS data from the Plate Boundary Observatory (PBO) and other geodetic quality GPS sites in North America, and from the ITRF2014 re-analysis. Initial analysis of the GAGE velocity field shows reduced root-mean-square (RMS) scatter of velocity estimate residuals when the North America Euler pole is estimated including the ICE-6G GIA mode. The reduction in the north-south direction is from 0.69 mm/yr to 0.52 mm/yr, in the east-west direction from 0.34 mm/yr to 0.30 mm/yr and in height from 0.93 mm/yr to 0.72 mm/yr. The reduction in the height RMS is not surprising since the contemporary geodetic height velocity estimates are used in the developing the ICE-6G model. Contemporary horizontal motions are not used the GIA model development, and the reduction in horizontal RMS provides a partial validation of the model. There is no reduction in the horizontal velocity residual when the ICE-5G model is used. Although removing the ICE-6G model before fitting an Euler pole for the North American plate reduces the RMS of the residuals, the pattern of residuals is still systematic suggesting possibly that a spherically symmetric viscosity model might not be adequate for accurate modeling of the horizontal motions associated with GIA in North America. This presentation in focus on the prospects and impacts of incorporating GIA models in plate-specific Euler poles with emphasis on North America.

  2. The General Medical Council: frame of reference or arbiter of morals?

    Science.gov (United States)

    Hill, D

    1977-01-01

    Many members of the public think of the General Medical Council (GMC) as the body which tries doctors: the doctors' law courts, as it were. And, except in the more sober of newspapers and news reports, the 'offences ' which receive the most publicity are those concerning alleged improper relations between doctors and patients. Professor Sir Denis Hill, in the following paper, which he read in the spring of this year to the annual conference of the London Medical Group devoted to a discussion of human sexuality, chose to examine the whole function of the General Medical Council as a frame of moral reference for doctors. Judging allegations of professional misconduct by doctors is the function of the Council's Disciplinary Committee. Judging sexual misconduct forms only a small part of their work. The GMC's responsibility covers the whole notion of morals and morality as it concerns doctors in their professional work. Sir Denis Hill stresses the modern thinking that morality must be learned and that attitudes are always shifting as society alters its norms of what is moral conduct. That is not to say that all that was previously considered not to be moral has now become acceptable but rather that other concepts have entered the field of moral debate. Therefore the GMC must constantly review the frame of reference it offers to doctors and the public may be surprised to learn that that process is never static. Sir Denis Hill in this paper is speaking personally and not as a member of the General Medical Council or of any of that body's special committees. PMID:926129

  3. Celestial Pole Offsets: Conversion From (dX, dY) to (d(psi), d(epsilon). Version 3

    National Research Council Canada - National Science Library

    Kaplan, George H

    2005-01-01

    ...; defined more precisely what is meant by the celestial pole; and provided a new definition of UT1 in terms of an angle that directly measures the rotation of Earth in the celestial reference system...

  4. Positional priming of visual pop-out search is supported by multiple spatial reference frames

    Science.gov (United States)

    Gokce, Ahu; Müller, Hermann J.; Geyer, Thomas

    2015-01-01

    The present study investigates the representations(s) underlying positional priming of visual ‘pop-out’ search (Maljkovic and Nakayama, 1996). Three search items (one target and two distractors) were presented at different locations, in invariant (Experiment 1) or random (Experiment 2) cross-trial sequences. By these manipulations it was possible to disentangle retinotopic, spatiotopic, and object-centered priming representations. Two forms of priming were tested: target location facilitation (i.e., faster reaction times – RTs– when the trial n target is presented at a trial n-1 target relative to n-1 blank location) and distractor location inhibition (i.e., slower RTs for n targets presented at n-1 distractor compared to n-1 blank locations). It was found that target locations were coded in positional short-term memory with reference to both spatiotopic and object-centered representations (Experiment 1 vs. 2). In contrast, distractor locations were maintained in an object-centered reference frame (Experiments 1 and 2). We put forward the idea that the uncertainty induced by the experiment manipulation (predictable versus random cross-trial item displacements) modulates the transition from object- to space-based representations in cross-trial memory for target positions. PMID:26136718

  5. Positional priming of visual pop-out search is supported by multiple spatial reference frames.

    Science.gov (United States)

    Gokce, Ahu; Müller, Hermann J; Geyer, Thomas

    2015-01-01

    The present study investigates the representations(s) underlying positional priming of visual 'pop-out' search (Maljkovic and Nakayama, 1996). Three search items (one target and two distractors) were presented at different locations, in invariant (Experiment 1) or random (Experiment 2) cross-trial sequences. By these manipulations it was possible to disentangle retinotopic, spatiotopic, and object-centered priming representations. Two forms of priming were tested: target location facilitation (i.e., faster reaction times - RTs- when the trial n target is presented at a trial n-1 target relative to n-1 blank location) and distractor location inhibition (i.e., slower RTs for n targets presented at n-1 distractor compared to n-1 blank locations). It was found that target locations were coded in positional short-term memory with reference to both spatiotopic and object-centered representations (Experiment 1 vs. 2). In contrast, distractor locations were maintained in an object-centered reference frame (Experiments 1 and 2). We put forward the idea that the uncertainty induced by the experiment manipulation (predictable versus random cross-trial item displacements) modulates the transition from object- to space-based representations in cross-trial memory for target positions.

  6. Positional priming of visual pop-out search is supported by multiple spatial reference frames

    Directory of Open Access Journals (Sweden)

    Ahu eGokce

    2015-06-01

    Full Text Available The present study investigates the representations(s underlying positional priming of visual ‘pop-out’ search (Maljkovic & Nakayama, 1996. Three search items (1 target and 2 distractors were presented at different locations, in invariant (Experiment 1 or random (Experiment 2 cross-trial sequences. By these manipulations it was possible to disentangle retinotopic, spatiotopic, and object-centered priming representations. Two forms of priming were tested: target location facilitation (i.e., faster reaction times – RTs– when the trial n target is presented at a trial n-1 target relative to n-1 blank location and distractor location inhibition (i.e., slower RTs for n targets presented at n-1 distractor compared to n-1 blank locations. It was found that target locations were coded in positional short-term memory with reference to both spatiotopic and object-centered representations (Experiment 1 vs. 2. In contrast, distractor locations were maintained in an object-centered reference frame (Experiments 1 and 2. We put forward the idea that the uncertainty induced by the experiment manipulation (predictable versus random cross-trial item displacements modulates the transition from object- to space-based representations in cross-trial memory for target positions.

  7. A new floating frame of reference formulation for flexible multibody dynamics

    NARCIS (Netherlands)

    Schilder, Jurnan Paul

    2017-01-01

    For the dynamic analysis of flexible multibody systems, three conceptually different descriptions are available and commonly used: the inertial frame formulations, the corotational formulations and the floating frame formulations. The differences between these formulations are mainly in the way they

  8. Spatial Frames of Reference in Traditional Negev Arabic: Language-to-Cognition Correlation.

    Science.gov (United States)

    Cerqueglini, Letizia

    2015-09-01

    Linguistic and cognitive tasks on spatial Frames of Reference (FoRs) in Traditional Negev Arabic (TNA) show that TNA is a referentially promiscuous language, using Intrinsic, Relative and Absolute FoRs. FoRs are selected in context according to culture-specific features of the ground (G). TNA speakers exclusively use the Absolute FoR in cognitive tasks, similarly to Mesoamerican languages (Bohnemeyer et al. in Proceedings of the 36th Annual Conference of the Cognitive Science Society, Austin, 2014). Absolute FoR in TNA is anchored on the four cardinal directions. Nevertheless, in TNA and in other varieties of Nomadic Arabic, geocentric sub-types of the Absolute FoR are also observable. Indeed, as in other Absolute-framing systems worldwide, different anchoring strategies (geocentric and astronomic) tend to coexist. I define their coexistence "Absolute Referential Modularity" (ARM). ARM appears in TNA in cognitive referential tasks and in some lexical items, not in linguistic tasks (as elaborated by Levinson et al. in Space stimuli kit 1.2: November 1992. Max Planck Institute for Psycholinguistics, Nijmegen, pp 7-14, 1992). Cardinal directions across Nomadic Arabic varieties show great cultural salience. They are associated with concrete geographical elements and encode topological relations: east-west axis encodes the mountain-sea opposition, beside many symbolic meanings, and encodes the oppositions Up/Down and Inside (familiar)/Outside (foreign). The detection of cognitive and linguistic Absolute referential practices-characterized by Modularity-and the cultural salience of cardinal directions within the whole Nomadic Arabic linguistic group, support the bias for Absolute cognition in promiscuous systems and its antecedence with respect to later linguistic referential strategies (Bohnemeyer et al. 2014). TNA linguistic promiscuity represents an innovation with respect to the cognitive concepts and demonstrates that language first generates semantic structures

  9. Frontiers in Relativistic Celestial Mechanics, Vol. 2, Applications and Experiments

    Science.gov (United States)

    Kopeikin, Sergei

    2014-08-01

    Relativistic celestial mechanics - investigating the motion celestial bodies under the influence of general relativity - is a major tool of modern experimental gravitational physics. With a wide range of prominent authors from the field, this two-volume series consists of reviews on a multitude of advanced topics in the area of relativistic celestial mechanics - starting from more classical topics such as the regime of asymptotically-flat spacetime, light propagation and celestial ephemerides, but also including its role in cosmology and alternative theories of gravity as well as modern experiments in this area. This second volume of a two-volume series covers applications of the theory as well as experimental verifications. From tools to determine light travel times in curved space-time to laser ranging between earth and moon and between satellites, and impacts on the definition of time scales and clock comparison techniques, a variety of effects is discussed. On the occasion of his 80-th birthday, these two volumes honor V. A. Brumberg - one of the pioneers in modern relativistic celestial mechanics. Contributions include: J. Simon, A. Fienga: Victor Brumberg and the French school of analytical celestial mechanics T. Fukushima: Elliptic functions and elliptic integrals for celestial mechanics and dynamical astronomy P. Teyssandier: New tools for determining the light travel time in static, spherically symmetric spacetimes beyond the order G2 J. Müller, L. Biskupek, F. Hofmann and E. Mai: Lunar laser ranging and relativity N. Wex: Testing relativistic celestial mechanics with radio pulsars I. Ciufolini et al.: Dragging of inertial frames, fundamental physics, and satellite laser ranging G. Petit, P. Wolf, P. Delva: Atomic time, clocks, and clock comparisons in relativistic spacetime: a review

  10. Investigation on Reference Frames and Time Systems in Multi-GNSS

    Directory of Open Access Journals (Sweden)

    Luca Nicolini

    2018-01-01

    Full Text Available Receivers able to track satellites belonging to different GNSSs (Global Navigation Satellite Systems are available on the market. To compute coordinates and velocities it is necessary to identify all the elements that contribute to interoperability of the different GNSSs. For example the timescales kept by different GNSSs have to be aligned. Receiver-specific biases, or firmware-dependent biases, need to be calibrated. The reference frame used in the representation of the orbits must be unique. In this paper we address the interoperability issues from the standpoint of a Single Point Positioning (SPP user, i.e., using pseudoranges and broadcast ephemeris. The biases between GNSSs timescales and receiver-dependent biases are analyzed for a set of 31 MGEX (Multi-GNSS Experiment stations over a time span of more than three years. Time series of biases between timescales of GPS (Global Positioning System, GLONASS (Global Navigation Satellite System, Galileo, BeiDou, QZSS (Quasi-Zenith Satellite System, SBAS (Satellite Based Augmentation System and NAVIC (Navigation with Indian Constellation are investigated, in addition to the identification of events like discontinuity of receiver-dependent biases due to firmware updating. The GPS broadcast reference frame is shown to be aligned to the one (IGS14 realized by the precise ephemeris of CODE (Center for Orbit Determination in Europe to within 0.1 m and 2 milliarcsec, with values dependent on whether IIR-A, IIR-B/M or IIF satellite blocks are considered. Larger offsets are observed for GLONASS, up to 1 m for GLONASS K satellites. For Galileo the alignment of the broadcast orbit to IGS14/CODE is again at the 0.1 m and several milliarcsec level, with the FOC (Full Operational Capability satellites slightly better than IOV (In Orbit Validation. For BeiDou an alignment of the broadcast frame to IGS14/CODE comparable to GLONASS is observed, regardless of whether IGSO (Inclined Geosynchronous Orbit or MEO

  11. A Terrestrial Reference Frame realised on the observation level using a GPS-LEO satellite constellation

    Science.gov (United States)

    Koenig, Daniel

    2018-02-01

    Applying a one-step integrated process, i.e. by simultaneously processing all data and determining all satellite orbits involved, a Terrestrial Reference Frame (TRF) consisting of a geometric as well as a dynamic part has been determined at the observation level using the EPOS-OC software of Deutsches GeoForschungsZentrum. The satellite systems involved comprise the Global Positioning System (GPS) as well as the twin GRACE spacecrafts. Applying a novel approach, the inherent datum defect has been overcome empirically. In order not to rely on theoretical assumptions this is done by carrying out the TRF estimation based on simulated observations and using the associated satellite orbits as background truth. The datum defect is identified here as the total of all three translations as well as the rotation about the z-axis of the ground station network leading to a rank-deficient estimation problem. To rectify this singularity, datum constraints comprising no-net translation (NNT) conditions in x, y, and z as well as a no-net rotation (NNR) condition about the z-axis are imposed. Thus minimally constrained, the TRF solution covers a time span of roughly a year with daily resolution. For the geometric part the focus is put on Helmert transformations between the a priori and the estimated sets of ground station positions, and the dynamic part is represented by gravity field coefficients of degree one and two. The results of a reference solution reveal the TRF parameters to be estimated reliably with high precision. Moreover, carrying out a comparable two-step approach using the same data and models leads to parameters and observational residuals of worse quality. A validation w.r.t. external sources shows the dynamic origin to coincide at a level of 5 mm or better in x and y, and mostly better than 15 mm in z. Comparing the derived GPS orbits to IGS final orbits as well as analysing the SLR residuals for the GRACE satellites reveals an orbit quality on the few cm level

  12. Harnessing Wind Power in Moving Reference Frames with Application to Vehicles

    Science.gov (United States)

    Goushcha, Oleg; Felicissimo, Robert; Danesh-Yazdi, Amir; Andreopoulos, Yiannis

    2017-11-01

    The extraction of wind power from unique configurations embedded in moving vehicles by using micro-turbine devices has been investigated. In such moving environments, the specific power of the air motion is much greater and less intermittent than in stationary wind turbines anchored to the ground in open atmospheric conditions. In a translational frame of reference, the rate of work done by the drag force acting on the wind harnessing device due the relative motion of air should be taken into account in the overall performance evaluation through an energy balance. A device with a venting tube has been tested that connects a high-pressure stagnating flow region in the front of the vehicle with a low-pressure region at its rear. Our analysis identified two key areas to focus on for potentially significant rewards: (1) Vehicles with high energy conversion efficiency which require a high mass flow rate through the venting duct, and (2) low efficiency vehicles with wakes, which will be globally affected by the introduction of the venting duct device in a manner that reduces their drag so that there is a net gain in power generation.

  13. Performance Evaluation of UPQC under Nonlinear Unbalanced Load Conditions Using Synchronous Reference Frame Based Control

    Science.gov (United States)

    Kota, Venkata Reddy; Vinnakoti, Sudheer

    2017-12-01

    Today, maintaining Power Quality (PQ) is very important in the growing competent world. With new equipments and devices, new challenges are also being put before power system operators. Unified Power Quality Conditioner (UPQC) is proposed to mitigate many power quality problems and to improve the performance of the power system. In this paper, an UPQC with Fuzzy Logic controller for capacitor voltage balancing is proposed in Synchronous Reference Frame (SRF) based control with Modified Phased Locked Loop (MPLL). The proposed controller with SRF-MPLL based control is tested under non-linear and unbalanced load conditions. The system is developed in Matlab/Simulink and its performance is analyzed under various conditions like non-linear, unbalanced load and polluted supply voltage including voltage sag/swells. Active and reactive power flow in the system, power factor and %THD of voltages and currents before and after compensation are also analyzed in this work. Results prove the applicability of the proposed scheme for power quality improvement. It is observed that the fuzzy controller gives better performance than PI controller with faster capacitor voltage balancing and also improves the dynamic performance of the system.

  14. A Global Terrestrial Reference Frame from simulated VLBI and SLR data in view of GGOS

    Science.gov (United States)

    Glaser, Susanne; König, Rolf; Ampatzidis, Dimitrios; Nilsson, Tobias; Heinkelmann, Robert; Flechtner, Frank; Schuh, Harald

    2017-07-01

    In this study, we assess the impact of two combination strategies, namely local ties (LT) and global ties (GT), on the datum realization of Global Terrestrial Reference Frames in view of the Global Geodetic Observing System requiring 1 mm-accuracy. Simulated Very Long Baseline Interferometry (VLBI) and Satellite Laser Ranging (SLR) data over a 7 year time span was used. The LT results show that the geodetic datum can be best transferred if the precision of the LT is at least 1 mm. Investigating different numbers of LT, the lack of co-located sites on the southern hemisphere is evidenced by differences of 9 mm in translation and rotation compared to the solution using all available LT. For the GT, the combination applying all Earth rotation parameters (ERP), such as pole coordinates and UT1-UTC, indicates that the rotation around the Z axis cannot be adequately transferred from VLBI to SLR within the combination. Applying exclusively the pole coordinates as GT, we show that the datum can be transferred with mm-accuracy within the combination. Furthermore, adding artificial stations in Tahiti and Nigeria to the current VLBI network results in an improvement in station positions by 13 and 12%, respectively, and in ERP by 17 and 11%, respectively. Extending to every day VLBI observations leads to 65% better ERP estimates compared to usual twice-weekly VLBI observations.

  15. Applicability of the "Frame of Reference" approach for environmental monitoring of offshore renewable energy projects.

    Science.gov (United States)

    Garel, Erwan; Rey, Cibran Camba; Ferreira, Oscar; van Koningsveld, Mark

    2014-08-01

    This paper assesses the applicability of the Frame of Reference (FoR) approach for the environmental monitoring of large-scale offshore Marine Renewable Energy (MRE) projects. The focus is on projects harvesting energy from winds, waves and currents. Environmental concerns induced by MRE projects are reported based on a classification scheme identifying stressors, receptors, effects and impacts. Although the potential effects of stressors on most receptors are identified, there are large knowledge gaps regarding the corresponding (positive and negative) impacts. In that context, the development of offshore MRE requires the implementation of fit-for-purpose monitoring activities aimed at environmental protection and knowledge development. Taking European legislation as an example, it is suggested to adopt standardized monitoring protocols for the enhanced usage and utility of environmental indicators. Towards this objective, the use of the FoR approach is advocated since it provides guidance for the definition and use of coherent set of environmental state indicators. After a description of this framework, various examples of applications are provided considering a virtual MRE project located in European waters. Finally, some conclusions and recommendations are provided for the successful implementation of the FoR approach and for future studies. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. New Insights on Cenozoic Plate Evolution and Mantle Dynamics in the Indo-Atlantic Hotspot Reference Frame

    Science.gov (United States)

    Quere, S.; Rowley, D. B.; Forte, A. M.; Moucha, R.

    2008-12-01

    We present a new model of Cenozoic plate motions in the Indo-Atlantic hotspot reference frame. This reconstruction is very different from the previous model established in the global (Pacific) hotspot reference frame by Gordon and Jurdy (1986), mainly because the latter model was based on three main postulates which have recently been placed into considerable doubt: the fixity of the Pacific hotspots, a change in direction of the Pacific plate used to explain the Hawaiian Emperor Bend and the introduction of the Chatham Rise plate. We present a number of new results. Firstly, we found a present-day slow northward drift in the Indo-Atlantic frame which differs markedly from the fast westward drift obtained in the Pacific frame. Secondly, this new plate history does not show a major Eocene plate reorganisation, nor an abrupt change in direction of the Pacific plate which has been previously invoked as an explanation for the Hawaiian Emperor Bend. Thirdly, we found that the net rotation of the lithosphere is very slow during the last 60 Myr, which suggests that the HS and NNR reference frames are quite similar.

  17. Combination of terrestrial reference frames based on space geodetic techniques in SHAO: methodology and main issues

    Science.gov (United States)

    He, Bing; Wang, Xiao-Ya; Hu, Xiao-Gong; Zhao, Qun-He

    2017-09-01

    Based on years of input from the four geodetic techniques (SLR, GPS, VLBI and DORIS), the strategies of the combination were studied in SHAO to generate a new global terrestrial reference frame as the material realization of the ITRS defined in IERS Conventions. The main input includes the time series of weekly solutions (or fortnightly for SLR 1983-1993) of observational data for satellite techniques and session-wise normal equations for VLBI. The set of estimated unknowns includes 3-dimensional Cartesian coordinates at the reference epoch 2005.0 of the stations distributed globally and their rates as well as the time series of consistent Earth Orientation Parameters (EOPs) at the same epochs as the input. Besides the final solution, namely SOL-2, generated by using all the inputs before 2015.0 obtained from short-term observation processing, another reference solution, namely SOL-1, was also computed by using the input before 2009.0 based on the same combination of procedures for the purpose of comparison with ITRF2008 and DTRF2008 and for evaluating the effect of the latest six more years of data on the combined results. The estimated accuracy of the x-component and y-component of the SOL-1 TRF-origin was better than 0.1 mm at epoch 2005.0 and better than 0.3 mm yr-1 in time evolution, either compared with ITRF2008 or DTRF2008. However, the z-component of the translation parameters from SOL-1 to ITRF2008 and DTRF2008 were 3.4 mm and -1.0 mm, respectively. It seems that the z-component of the SOL-1 TRF-origin was much closer to the one in DTRF2008 than the one in ITRF2008. The translation parameters from SOL-2 to ITRF2014 were 2.2, -1.8 and 0.9 mm in the x-, y- and z-components respectively with rates smaller than 0.4 mm yr-1. Similarly, the scale factor transformed from SOL-1 to DTRF2008 was much smaller than that to ITRF2008. The scale parameter from SOL-2 to ITRF2014 was -0.31 ppb with a rate lower than 0.01 ppb yr-1. The external precision (WRMS) compared

  18. IAEA activities related to safety indicators, time frames and reference scenarios

    International Nuclear Information System (INIS)

    Batandjieva, B.; Hioki, K.; Metcalf, P.

    2002-01-01

    The fundamental principles for the safe management of radioactive waste have been agreed internationally and form the basis for the Joint Convention on the Safety of Spent Fuel Management and on the Safety of Radioactive Waste Management that entered into force in June 2001. Protection of human health and the environment and safety of facilities (including radioactive waste disposal facilities) are widely recognised principles to be followed and demonstrated in post-closure safety assessment of waste repositories. Dose and risk are at present internationally agreed safety criteria, used for judging the acceptability of such facilities. However, there have been a number of activities initiated and co-ordinated by the International Atomic Energy Agency (IAEA) which have provided an international forum for discussion and consensus building on the use safety indicators which are complementary to dose and risk. The Agency has been working on the definition of other safety indicators, such as flux, time, environmental concentration, etc.; the desired characteristics, and use of these indicators in different time frames. The IAEA has focused on safety indicators related to geological disposal, exploring their role in the development of a safety case, evaluating the advantages and disadvantages of using other safety indicators and how they complement the dose and risk indicators. The use of these indicators have been discussed also from regulatory perspective, mainly in terms of achieving reasonable assurance and confidence in safety assessments for waste repositories and decision making in the presence of uncertainty in the context of disposal of long-lived waste. Considerable effort has also been expended by the Agency on the development and application of principles for defining critical groups and biospheres for deep geological repositories. One of the important and successful IAEA programmes in this field is the Biosphere Modelling and Assessment (BIOMASS) project

  19. Small-signal model of a decoupled double synchronous reference frame current controller

    DEFF Research Database (Denmark)

    Dowlatabadi, Mohammadkazem Bakhshizadeh; Hjerrild, Jester; Kocewiak, Lukasz

    2016-01-01

    the dq signals are not dc anymore, and therefore, linearization cannot be done. In this paper a Decoupled Double Synchronous Frame PLL is used to eliminate the oscillations in the dq frame signals. The small signal model of this PLL including an unbalanced current controller is presented in this paper....

  20. Cognitive Ability, Academic Achievement and Academic Self-Concept: Extending the Internal/External Frame of Reference Model

    Science.gov (United States)

    Chen, Ssu-Kuang; Hwang, Fang-Ming; Yeh, Yu-Chen; Lin, Sunny S. J.

    2012-01-01

    Background: Marsh's internal/external (I/E) frame of reference model depicts the relationship between achievement and self-concept in specific academic domains. Few efforts have been made to examine concurrent relationships among cognitive ability, achievement, and academic self-concept (ASC) within an I/E model framework. Aim: To simultaneously…

  1. Flying over uneven moving terrain based on optic-flow cues without any need for reference frames or accelerometers.

    Science.gov (United States)

    Expert, Fabien; Ruffier, Franck

    2015-02-26

    Two bio-inspired guidance principles involving no reference frame are presented here and were implemented in a rotorcraft, which was equipped with panoramic optic flow (OF) sensors but (as in flying insects) no accelerometer. To test these two guidance principles, we built a tethered tandem rotorcraft called BeeRotor (80 grams), which was tested flying along a high-roofed tunnel. The aerial robot adjusts its pitch and hence its speed, hugs the ground and lands safely without any need for an inertial reference frame. The rotorcraft's altitude and forward speed are adjusted via two OF regulators piloting the lift and the pitch angle on the basis of the common-mode and differential rotor speeds, respectively. The robot equipped with two wide-field OF sensors was tested in order to assess the performances of the following two systems of guidance involving no inertial reference frame: (i) a system with a fixed eye orientation based on the curved artificial compound eye (CurvACE) sensor, and (ii) an active system of reorientation based on a quasi-panoramic eye which constantly realigns its gaze, keeping it parallel to the nearest surface followed. Safe automatic terrain following and landing were obtained with CurvACE under dim light to daylight conditions and the active eye-reorientation system over rugged, changing terrain, without any need for an inertial reference frame.

  2. Teachers' Interpretations of the Internet. An Applied Case Study for the Evaluation of Technological Frames of Reference

    Science.gov (United States)

    Camilleri, Patrick

    2012-01-01

    In 1994 Orlikowski and Gash articulated Technological Frames of Reference as a systematic theoretical lens to examine technological developments in organisations. A decade later, in 2004, Davidson and Pai expressed concern that while the lens was widely cited in academic discourse, the incidence and adoption of the model as an analytical framework…

  3. Business vs. Cultural Frames of Reference in Group Decision Making: Interactions among Austrian, Finnish, and Swedish Business Students.

    Science.gov (United States)

    Auer-Rizzi, Werner; Berry Michael

    2000-01-01

    Examines ways business and cultural frames of reference affect decision making in multicultural groups. Finds students' reactions to two class activities shows how "groupthink" arose in both exercises; cultural interference paralyzed group decision making in one group; and cultural interference demonstrated the importance of a cultural…

  4. An improved synchronous reference frame phase-locked loop for stand-alone variable speed constant frequency power generation systems

    DEFF Research Database (Denmark)

    Liu, Yi; Xu, Wei; Ke, Longzhang

    2017-01-01

    The phase-locked loop (PLL) based on conventional synchronous reference frame, i.e. dqPLL, is usually employed in grid-connected variable speed constant frequency (VSCF) power generation systems (PGSs). However, the voltage amplitude drop of stand-alone PGSs is often greater than that of the grid...

  5. Frame-of-Reference Training: Establishing Reliable Assessment of Teaching Effectiveness.

    Science.gov (United States)

    Newman, Lori R; Brodsky, Dara; Jones, Richard N; Schwartzstein, Richard M; Atkins, Katharyn Meredith; Roberts, David H

    2016-01-01

    Frame-of-reference (FOR) training has been used successfully to teach faculty how to produce accurate and reliable workplace-based ratings when assessing a performance. We engaged 21 Harvard Medical School faculty members in our pilot and implementation studies to determine the effectiveness of using FOR training to assess health professionals' teaching performances. All faculty were novices at rating their peers' teaching effectiveness. Before FOR training, we asked participants to evaluate a recorded lecture using a criterion-based peer assessment of medical lecturing instrument. At the start of training, we discussed the instrument and emphasized its precise behavioral standards. During training, participants practiced rating lectures and received immediate feedback on how well they categorized and scored performances as compared with expert-derived scores of the same lectures. At the conclusion of the training, we asked participants to rate a post-training recorded lecture to determine agreement with the experts' scores. Participants and experts had greater rating agreement for the post-training lecture compared with the pretraining lecture. Through this investigation, we determined that FOR training is a feasible method to teach faculty how to accurately and reliably assess medical lectures. Medical school instructors and continuing education presenters should have the opportunity to be observed and receive feedback from trained peer observers. Our results show that it is possible to use FOR rater training to teach peer observers how to accurately rate medical lectures. The process is time efficient and offers the prospect for assessment and feedback beyond traditional learner evaluation of instruction.

  6. Mapping spatial frames of reference onto time: a review of theoretical accounts and empirical findings.

    Science.gov (United States)

    Bender, Andrea; Beller, Sieghard

    2014-09-01

    When speaking and reasoning about time, people around the world tend to do so with vocabulary and concepts borrowed from the domain of space. This raises the question of whether the cross-linguistic variability found for spatial representations, and the principles on which these are based, may also carry over to the domain of time. Real progress in addressing this question presupposes a taxonomy for the possible conceptualizations in one domain and its consistent and comprehensive mapping onto the other-a challenge that has been taken up only recently and is far from reaching consensus. This article aims at systematizing the theoretical and empirical advances in this field, with a focus on accounts that deal with frames of reference (FoRs). It reviews eight such accounts by identifying their conceptual ingredients and principles for space-time mapping, and it explores the potential for their integration. To evaluate their feasibility, data from some thirty empirical studies, conducted with speakers of sixteen different languages, are then scrutinized. This includes a critical assessment of the methods employed, a summary of the findings for each language group, and a (re-)analysis of the data in view of the theoretical questions. The discussion relates these findings to research on the mental time line, and explores the psychological reality of temporal FoRs, the degree of cross-domain consistency in FoR adoption, the role of deixis, and the sources and extent of space-time mapping more generally. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. The evaluation of a frame-of-reference training programme for intern psychometrists

    Directory of Open Access Journals (Sweden)

    Gerdi Mulder

    2013-07-01

    Full Text Available Orientation: The use of assessment centres (ACs has drastically increased over the past decade. However, ACs are constantly confronted with the lack of construct validity. One aspect of ACs that could improve the construct validity significantly is that of assessor training. Unfortunately untrained or poorly trained assessors are often used in AC processes. Research purpose: The purpose of this research was to evaluate a frame-of-reference (FOR programme to train intern psychometrists as assessors at an assessment centre. Motivation of study: The role of an assessor is important in an AC; therefore it is vital for an assessor to be able to evaluate and observe candidates’ behaviour adequately. Commencing with this training in a graduate psychometrist programme gives the added benefit of sending skilled psychometrists to the workplace. Research design, approach and method: A quantitative research approach was implemented, utilising a randomised pre-test-post-test comparison group design. Industrial Psychology postgraduate students (N = 22 at a South African university were used and divided into an experimental group (n = 11 and control group (n = 11. Three typical AC simulations were utilised as pre- and post-tests, and the ratings obtained from both groups were statistically analysed to determine the effect of the FOR training programme. Main findings: The data indicated that there was a significant increase in the familiarity of the participants with the one-on-one simulation and the group discussion simulation. Practical/managerial implications: Training intern psychometrists in a FOR programme could assist organisations in the appointment of more competent assessors. Contribution/value-add: To design an assessor training programme using FOR training for intern psychometrists in the South African context, specifically by incorporating this programme into the training programme for Honours students at universities.

  8. A relative frame of reference underlies reversed depth perception in anticorrelated random-dot stereograms.

    Science.gov (United States)

    Aoki, Shuntaro C; Shiozaki, Hiroshi M; Fujita, Ichiro

    2017-10-01

    Binocular disparity is represented by interocular cross-correlation of visual images in the striate and some extrastriate cortices. This correlation-based representation produces reversed depth perception in a binocularly anticorrelated random-dot stereogram (aRDS) when it is accompanied by an adjacent correlated RDS (cRDS). Removal of the cRDS or spatial separation between the aRDS and cRDS abolishes reversed depth perception. However, how an immediate plane supports reversed depth perception is unclear. One possible explanation is that the correlation-based representation generates reversed depth based on the relative disparity between the aRDS and cRDS rather than the absolute disparity of the aRDS. Here, we psychophysically tested this hypothesis. We found that participants perceived reversed depth in an aRDS with zero absolute disparity when it was surrounded by a cRDS with nonzero absolute disparity (i.e., nonzero relative disparity), suggesting a role of relative disparity on the depth reversal. In addition, manipulation of the absolute disparities of the central aRDS and surrounding cRDS caused depth perception to reverse with respect to the depth of the surround. Further, depth reversal persisted after swapping the locations of the two RDSs. A model of relative-disparity encoding explains all these results. We conclude that reversed depth perception in aRDSs occurs in a relative frame of reference and suggest that the visual system contains correlation-based representation that encodes relative disparity.

  9. Assessment of the possible contribution of space ties on-board GNSS satellites to the terrestrial reference frame

    Science.gov (United States)

    Bruni, Sara; Rebischung, Paul; Zerbini, Susanna; Altamimi, Zuheir; Errico, Maddalena; Santi, Efisio

    2018-04-01

    The realization of the international terrestrial reference frame (ITRF) is currently based on the data provided by four space geodetic techniques. The accuracy of the different technique-dependent materializations of the frame physical parameters (origin and scale) varies according to the nature of the relevant observables and to the impact of technique-specific errors. A reliable computation of the ITRF requires combining the different inputs, so that the strengths of each technique can compensate for the weaknesses of the others. This combination, however, can only be performed providing some additional information which allows tying together the independent technique networks. At present, the links used for that purpose are topometric surveys (local/terrestrial ties) available at ITRF sites hosting instruments of different techniques. In principle, a possible alternative could be offered by spacecrafts accommodating the positioning payloads of multiple geodetic techniques realizing their co-location in orbit (space ties). In this paper, the GNSS-SLR space ties on-board GPS and GLONASS satellites are thoroughly examined in the framework of global reference frame computations. The investigation focuses on the quality of the realized physical frame parameters. According to the achieved results, the space ties on-board GNSS satellites cannot, at present, substitute terrestrial ties in the computation of the ITRF. The study is completed by a series of synthetic simulations investigating the impact that substantial improvements in the volume and quality of SLR observations to GNSS satellites would have on the precision of the GNSS frame parameters.

  10. The Celestial Mechanics of Newton

    Indian Academy of Sciences (India)

    Newton's Principia consists of three books; the third dealing with the The System of the World puts forth. Newton's views on celestial mechanics. This third book is indeed the heart of Newton's "natural philosophy" which draws heavily on the mathematical results derived in the first two books. Here he systematises his math-.

  11. The Celestial Mechanics of Newton

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 11; Issue 12. The Celestial Mechanics of Newton. Dipankar Bhattacharya. General Article Volume 11 Issue 12 December 2006 pp 35-44. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/011/12/0035-0044 ...

  12. Celestial navigation in a nutshell

    CERN Document Server

    Schlereth, Hewitt

    2000-01-01

    Celestial Navigation in a Nutshell demonstrates how to take sights by the sun, moon, stars, and planets, discussing the advantages and disadvantages of each method. The reader is taken carefully through several examples and situational illustrations, making this a most effective self-teaching guide. Common errors are reviewed and several tips on how to improve accuracy are given.

  13. Mimicking Celestial Mechanics in Metamaterials

    Science.gov (United States)

    2009-09-01

    general theory of relativity is the bending of light that passes near massive celestial objects such as stars, nebulas or galaxies . This effect...optical metamaterial exhibiting negative refractive index. Nature 455, 376–379 (2008). 14. Shapiro, S. L. & Teukolsky, S. A.White Dwarfs , and Neutron

  14. A radio/optical reference frame. 5: Additional source positions in the mid-latitude southern hemisphere

    Science.gov (United States)

    Russell, J. L.; Reynolds, J. E.; Jauncey, D. L.; de Vegt, C.; Zacharias, N.; Ma, C.; Fey, A. L.; Johnston, K. J.; Hindsley, R.; Hughes, J. A.; Malin, D. F.; White, G. L.; Kawaguchi, N.; Takahashi, Y.

    1994-01-01

    We report new accurate radio position measurements for 30 sources, preliminary positions for two sources, improved radio postions for nine additional sources which had limited previous observations, and optical positions and optical-radio differences for six of the radio sources. The Very Long Baseline Interferometry (VLBI) observations are part of the continuing effort to establish a global radio reference frame of about 400 compact, flat spectrum sources, which are evenly distributed across the sky. The observations were made using Mark III data format in four separate sessions in 1988-89 with radio telescopes at Tidbinbilla, Australia, Kauai, USA, and Kashima, Japan. We observed a total of 54 sources, including ten calibrators and three which were undetected. The 32 new source positions bring the total number in the radio reference frame catalog to 319 (172 northern and 147 southern) and fill in the zone -25 deg greater than delta greater than -45 deg which, prior to this list, had the lowest source density. The VLBI positions have an average formal precision of less than 1 mas, although unknown radio structure effects of about 1-2 mas may be present. The six new optical postion measurements are part of the program to obtain positions of the optical counterparts of the radio reference frame source and to map accurately the optical on to the radio reference frames. The optical measurements were obtained from United States Naval Observatory (USNO) Black Birch astrograph plates and source plates from the AAT, and Kitt Peak National Observatory (KPNO) 4 m, and the European Southern Observatory (ESO) Schmidt. The optical positions have an average precision of 0.07 sec, mostly due to the zero point error when adjusted to the FK5 optical frame using the IRS catalog. To date we have measured optical positions for 46 sources.

  15. Are OPERA neutrinos faster than light because of non-inertial reference frames?

    Science.gov (United States)

    Germanà, C.

    2012-02-01

    Context. Recent results from the OPERA experiment reported a neutrino beam traveling faster than light. The challenging experiment measured the neutrino time of flight (TOF) over a baseline from the CERN to the Gran Sasso site, concluding that the neutrino beam arrives ~60 ns earlier than a light ray would do. Because the result, if confirmed, has an enormous impact on science, it might be worth double-checking the time definitions with respect to the non-inertial system in which the neutrino travel time was measured. An observer with a clock measuring the proper time τ free of non-inertial effects is the one located at the solar system barycenter (SSB). Aims: Potential problems in the OPERA data analysis connected with the definition of the reference frame and time synchronization are emphasized. We aim to investigate the synchronization of non-inertial clocks on Earth by relating this time to the proper time of an inertial observer at SSB. Methods: The Tempo2 software was used to time-stamp events observed on the geoid with respect to the SSB inertial observer time. Results: Neutrino results from OPERA might carry the fingerprint of non-inertial effects because they are timed by terrestrial clocks. The CERN-Gran Sasso clock synchronization is accomplished by applying corrections that depend on special and general relativistic time dilation effects at the clocks, depending on the position of the clocks in the solar system gravitational well. As a consequence, TOF distributions are centered on values shorter by tens of nanoseconds than expected, integrating over a period from April to December, longer if otherwise. It is worth remarking that the OPERA runs have always been carried out from April/May to November. Conclusions: If the analysis by Tempo2 holds for the OPERA experiment, the excellent measurement by the OPERA collaboration will turn into a proof of the general relativity theory in a weak field approximation. The analysis presented here is falsifiable

  16. The Human Retrosplenial Cortex and Thalamus Code Head Direction in a Global Reference Frame.

    Science.gov (United States)

    Shine, Jonathan P; Valdés-Herrera, José P; Hegarty, Mary; Wolbers, Thomas

    2016-06-15

    Spatial navigation is a multisensory process involving integration of visual and body-based cues. In rodents, head direction (HD) cells, which are most abundant in the thalamus, integrate these cues to code facing direction. Human fMRI studies examining HD coding in virtual environments (VE) have reported effects in retrosplenial complex and (pre-)subiculum, but not the thalamus. Furthermore, HD coding appeared insensitive to global landmarks. These tasks, however, provided only visual cues for orientation, and attending to global landmarks did not benefit task performance. In the present study, participants explored a VE comprising four separate locales, surrounded by four global landmarks. To provide body-based cues, participants wore a head-mounted display so that physical rotations changed facing direction in the VE. During subsequent MRI scanning, subjects saw stationary views of the environment and judged whether their orientation was the same as in the preceding trial. Parameter estimates extracted from retrosplenial cortex and the thalamus revealed significantly reduced BOLD responses when HD was repeated. Moreover, consistent with rodent findings, the signal did not continue to adapt over repetitions of the same HD. These results were supported by a whole-brain analysis showing additional repetition suppression in the precuneus. Together, our findings suggest that: (1) consistent with the rodent literature, the human thalamus may integrate visual and body-based, orientation cues; (2) global reference frame cues can be used to integrate HD across separate individual locales; and (3) immersive training procedures providing full body-based cues may help to elucidate the neural mechanisms supporting spatial navigation. In rodents, head direction (HD) cells signal facing direction in the environment via increased firing when the animal assumes a certain orientation. Distinct brain regions, the retrosplenial cortex (RSC) and thalamus, code for visual and

  17. Nursing home staff members' subjective frames of reference on residents' achievement of ego integrity: A Q-methodology study.

    Science.gov (United States)

    Lim, Sun-Young; Chang, Sung-Ok

    2018-01-01

    To discover the structure of the frames of reference for nursing home staff members' subjective judgment of residents' achievement of ego integrity. Q-methodology was applied. Twenty-eight staff members who were working in a nursing home sorted 34 Q-statements into the shape of a normal distribution. A centroid factor analysis and varimax rotation, using the PQ-method program, revealed four factors: identifying clues to residents' positive acceptance of their whole life span, identifying residents' ways of enjoying their current life, referencing residents' attitudes and competencies toward harmonious relationships, and identifying residents' integrated efforts to establish self-esteem. These subjective frames of reference need to be investigated in order to improve the relationships with nursing home residents and their quality of life. Consequently, the fundamental monitoring tools to help staff members make subjective judgments can be formed. © 2017 Japan Academy of Nursing Science.

  18. Hybrid state‐space time integration in a rotating frame of reference

    DEFF Research Database (Denmark)

    Krenk, Steen; Nielsen, Martin Bjerre

    2011-01-01

    terms, while the centrifugal forces are represented implicitly via the hybrid state‐space format. An angular momentum and energy conserving algorithm is developed, in which the angular velocity of the frame is represented by its mean value. A consistent algorithmic damping scheme is identified...

  19. Optimal Performance Design Guideline of Hybrid Reference Frame-based Dual Loop Control Strategy for Stand-Alone Single-Phase Inverters

    DEFF Research Database (Denmark)

    Han, Yang; Jiang, Ai-Ting; Coelho, Ernane A. A.

    2018-01-01

    The dual-loop control strategies in hybrid reference frame (HRF) for single-phase voltage source inverters (VSIs) in islanded operation mode is studied, which applies a capacitor voltage shaping loop in the synchronous reference frame (SRF) and a capacitor current shaping loop in the stationary r...

  20. Roadmap to a mutually consistent set of offshore vertical reference frames

    NARCIS (Netherlands)

    Slobbe, D.C.

    2013-01-01

    This thesis presents a combined approach for the realization of the (quasi-)geoid as a height reference surface and the vertical reference surface at sea (chart datum). This approach, specifically designed for shallow seas and coastal waters, provides the relation between the two vertical reference

  1. Personality measures as predictors of job satisfaction from a frame-of-reference perspective

    OpenAIRE

    Lättman, Katrin

    2012-01-01

    Extending previous research by Bowling and Burns (2010), a comparison of work personality to general personality indicate that work personality has a stronger relationship with job satisfaction (work-criteria) than does general personality, and, contrary to the above study, general personality has a stronger relationship with life satisfaction (general criteria) than does work personality. Work personality is defined as the personality in the context of work, by promoting the use of a frame-o...

  2. Can space ties on board GNSS satellites replace terrestrial ties in the implementation of Terrestrial Reference Frames?

    Science.gov (United States)

    Bruni, Sara; Zerbini, Susanna; Altamimi, Zuheir; Rebischung, Paul; Errico, Maddalena; Santi, Efisio

    2016-04-01

    The realization of Terrestrial Reference Frames (TRFs) must be periodically updated in order to account for newly acquired observations and for upgrades in data analysis procedures and/or combination techniques. Any innovative computation strategy should ameliorate the definition of the frame physical parameters, upon which a number of scientific applications critically rely. On the basis of the requirements of scientific cutting edge studies, the geodetic community has estimated that the present day challenge in the determination of TRFs is to provide a frame that is accurate and long-term stable at the level of 1 mm and 0.1 mm/y respectively. This work aims at characterizing the frame realized by a combination of Satellite Laser Ranging (SLR) and Global Navigation Satellite Systems (GNSS) observations via their co-location on board GNSS spacecrafts. In particular, it is established how such a frame compares to the traditional ITRF computation and what is the impact on the realization of the frame origin and scale. Four years of data from a global network encompassing about one hundred GNSS stations and all SLR sites have been analyzed. In order to ensure the highest possible consistency, the raw data of both techniques are treated with the same analysis Software (Bernese GNSS Software 5.2) following IERS2010 Conventions. Both weekly and long term solutions are carried out exploiting either the Bernese or the Combination and Analysis of Terrestrial Reference Frames (CATREF) Software packages. We present the results of a combination study involving GNSS data and SLR observations to the two LAGEOS and to the GNSS satellites equipped with retroreflector arrays. The latter type of measurements is currently not included in the computation of the official ITRF solutions. The assessment of the benefit that they could provide to the definition of the origin and scale of the ITRF is however worth investigating, as such data provide the potential for linking the GNSS and

  3. Estimation of surgical tool-tip tracking error distribution in coordinate reference frame involving pivot calibration uncertainty.

    Science.gov (United States)

    Min, Zhe; Ren, Hongliang; Meng, Max Q-H

    2017-10-01

    Accurate understanding of surgical tool-tip tracking error is important for decision making in image-guided surgery. In this Letter, the authors present a novel method to estimate/model surgical tool-tip tracking error in which they take pivot calibration uncertainty into consideration. First, a new type of error that is referred to as total target registration error (TTRE) is formally defined in a single-rigid registration. Target localisation error (TLE) in two spaces to be registered is considered in proposed TTRE formulation. With first-order approximation in fiducial localisation error (FLE) or TLE magnitude, TTRE statistics (mean, covariance matrix and root-mean-square (RMS)) are then derived. Second, surgical tool-tip tracking error in optical tracking system (OTS) frame is formulated using TTRE when pivot calibration uncertainty is considered. Finally, TTRE statistics of tool-tip in OTS frame are then propagated relative to a coordinate reference frame (CRF) rigid-body. Monte Carlo simulations are conducted to validate the proposed error model. The percentage passing statistical tests that there is no difference between simulated and theoretical mean and covariance matrix of tool-tip tracking error in CRF space is more than 90% in all test cases. The RMS percentage difference between simulated and theoretical tool-tip tracking error in CRF space is within 5% in all test cases.

  4. New Methods of Celestial Mechanics

    CERN Document Server

    Vrbik, Jan

    2010-01-01

    The book is trying to explain the main features of Celestial Mechanics using a new technique (in this, it is very unique). Its emphasis, in terms of applications, is on the Solar System, including its most peculiar properties (such as chaos, resonances, relativistic corrections, etc.). All results are derived in a reasonably transparent manner, so that anyone with a PC and a rudimentary knowledge of Mathematica can readily verify them, and even extend them to explore new situations, if desired. The more mathematically oriented reader may also appreciate seeing quaternions as the basic algebric

  5. General-relativistic celestial mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Treder, H.-J.

    1980-01-01

    The fundamental principles of general relativistic dynamics are deduced from Einstein's field equations and one- and two-particle problems in relativistic celestial mechanics are considered. Different opinions as to the physical meaning of calculations of gravitational radiation for double stars are discussed. It is shown that these different opinions are based on different interpretations of Einstein's gravitational equations as generally covariant determinations of the space-time metric and as gauge-invariant tensor field equations in a given space-time background.

  6. A Terrestrial Reference Frame (TRF, coordinates and velocities for South American stations: contributions to Central Andes geodynamics

    Directory of Open Access Journals (Sweden)

    M. V. Mackern

    2009-12-01

    Full Text Available Satellite positioning systems allow the fixing of the location of a point on the Earth's surface with very good precision and accuracy. To do this, however, it is necessary to determine the point coordinates taking account the reference system and the movements that affect them because of tectonic plate movements. These reference systems are materialized by a significant number of continuous measurement stations in South America. In SIRGAS (Sistema de Referencia Geocéntrico para las Américas, there are four Analysis Centers that process the data collected from satellites of the Global Navigation Satellite Systems (GNSS, with the primary purpose to maintain the international terrestrial reference frame through calculation of the coordinates and velocities of the continuous GNSS stations of the SIRGAS-CON Network.

    In this work, we demonstrate the quality of the solutions from CIMA, one of the SIRGAS official processing centers operating in Mendoza, Argentina, in comparison with other South American processing centers. The importance of precise calculations of coordinates and velocities in a global frame is also shown. Finally, we give estimations of velocities from stations located within deformation zones in the Central Andes.

  7. Non-linearity of geocentre motion and its impact on the origin of the terrestrial reference frame

    Science.gov (United States)

    Dong, Danan; Qu, Weijing; Fang, Peng; Peng, Dongju

    2014-08-01

    The terrestrial reference frame is a cornerstone for modern geodesy and its applications for a wide range of Earth sciences. The underlying assumption for establishing a terrestrial reference frame is that the motion of the solid Earth's figure centre relative to the mass centre of the Earth system on a multidecadal timescale is linear. However, past international terrestrial reference frames (ITRFs) showed unexpected accelerated motion in their translation parameters. Based on this underlying assumption, the inconsistency of relative origin motions of the ITRFs has been attributed to data reduction imperfection. We investigated the impact of surface mass loading from atmosphere, ocean, snow, soil moisture, ice sheet, glacier and sea level from 1983 to 2008 on the geocentre variations. The resultant geocentre time-series display notable trend acceleration from 1998 onward, in particular in the z-component. This effect is primarily driven by the hydrological mass redistribution in the continents (soil moisture, snow, ice sheet and glacier). The acceleration is statistically significant at the 99 per cent confidence level as determined using the Mann-Kendall test, and it is highly correlated with the satellite laser ranging determined translation series. Our study, based on independent geophysical and hydrological models, demonstrates that, in addition to systematic errors from analysis procedures, the observed non-linearity of the Earth-system behaviour at interannual timescales is physically driven and is able to explain 42 per cent of the disparity between the origins of ITRF2000 and ITRF2005, as well as the high level of consistency between the ITRF2005 and ITRF2008 origins.

  8. Reference-Frame-Independent Quantum-Key-Distribution Server with a Telecom Tether for an On-Chip Client

    Science.gov (United States)

    Zhang, P.; Aungskunsiri, K.; Martín-López, E.; Wabnig, J.; Lobino, M.; Nock, R. W.; Munns, J.; Bonneau, D.; Jiang, P.; Li, H. W.; Laing, A.; Rarity, J. G.; Niskanen, A. O.; Thompson, M. G.; O'Brien, J. L.

    2014-04-01

    We demonstrate a client-server quantum key distribution (QKD) scheme. Large resources such as laser and detectors are situated at the server side, which is accessible via telecom fiber to a client requiring only an on-chip polarization rotator, which may be integrated into a handheld device. The detrimental effects of unstable fiber birefringence are overcome by employing the reference-frame-independent QKD protocol for polarization qubits in polarization maintaining fiber, where standard QKD protocols fail, as we show for comparison. This opens the way for quantum enhanced secure communications between companies and members of the general public equipped with handheld mobile devices, via telecom-fiber tethering.

  9. Modeling, analysis, and design of stationary reference frame droop controlled parallel three-phase voltage source inverters

    DEFF Research Database (Denmark)

    Vasquez, Juan Carlos; Guerrero, Josep M.; Savaghebi, Mehdi

    2011-01-01

    Power electronics based microgrids consist of a number of voltage source inverters (VSIs) operating in parallel. In this paper, the modeling, control design, and stability analysis of three-phase VSIs are derived. The proposed voltage and current inner control loops and the mathematical models...... of the VSIs were based on the stationary reference frame. A hierarchical control for the paralleled VSI system was developed based on three levels. The primary control includes the droop method and the virtual impedance loops, in order to share active and reactive power. The secondary control restores...

  10. Individual differences in the ability to identify, select and use appropriate frames of reference for perceptuo-motor control.

    Science.gov (United States)

    Isableu, B; Ohlmann, T; Cremieux, J; Vuillerme, N; Amblard, B; Gresty, M A

    2010-09-01

    The causes of the interindividual differences (IDs) in how we perceive and control spatial orientation are poorly understood. Here, we propose that IDs partly reflect preferred modes of spatial referencing and that these preferences or "styles" are maintained from the level of spatial perception to that of motor control. Two groups of experimental subjects, one with high visual field dependency (FD) and one with marked visual field independency (FI) were identified by the Rod and Frame Test, which identifies relative dependency on a visual frame of reference (VFoR). FD and FI subjects were tasked with standing still in conditions of increasing postural difficulty while visual cues of self-orientation (a visual frame tilted in roll) and self-motion (in stroboscopic illumination) were varied and in darkness to assess visual dependency. Postural stability, overall body orientation and modes of segmental stabilization relative to either external (space) or egocentric (adjacent segments) frames of reference in the roll plane were analysed. We hypothesized that a moderate challenge to balance should enhance subjects' reliance on VFoR, particularly in FD subjects, whereas a substantial challenge should constrain subjects to use a somatic-vestibular based FoR to prevent falling in which case IDs would vanish. The results showed that with increasing difficulty, FD subjects became more unstable and more disoriented shown by larger effects of the tilted visual frame on posture. Furthermore, their preference to coalign body/VFoR coordinate systems lead to greater fixation of the head-trunk articulation and stabilization of the hip in space, whereas the head and trunk remained more stabilized in space with the hip fixed on the leg in FI subjects. These results show that FD subjects have difficulties at identifying and/or adopting a more appropriate FoR based on proprioceptive and vestibular cues to regulate the coalignment of posturo/exocentric FoRs. The FI subjects' resistance

  11. Observation of Celestial Phenomena in Ancient China

    Science.gov (United States)

    Sun, Xiaochun

    Because of the need for calendar-making and portent astrology, the Chinese were diligent and meticulous observers of celestial phenomena. China has maintained the longest continuous historical records of celestial phenomena in the world. Extraordinary or abnormal celestial events were particularly noted because of their astrological significance. The historical records cover various types of celestial phenomena, which include solar and lunar eclipses, sunspots, "guest stars" (novae or supernovae as we understand today), comets and meteors, and all kinds of planetary phenomena. These records provide valuable historical data for astronomical studies today.

  12. The constitution of a Common Frame of Reference for European contract law

    NARCIS (Netherlands)

    Mak, C.

    2008-01-01

    This sectoral report is meant to sketch in broad lines the current views on the so-called ‘constitutionalisation’ of European contract law. To what extent does the application of fundamental rights in the regulation of contractual disputes refer or contribute to an underlying system of values of

  13. Power Quality Improvement by Unified Power Quality Conditioner Based on CSC Topology Using Synchronous Reference Frame Theory

    Directory of Open Access Journals (Sweden)

    Rajasekaran Dharmalingam

    2014-01-01

    Full Text Available This paper deals with the performance of unified power quality conditioner (UPQC based on current source converter (CSC topology. UPQC is used to mitigate the power quality problems like harmonics and sag. The shunt and series active filter performs the simultaneous elimination of current and voltage problems. The power fed is linked through common DC link and maintains constant real power exchange. The DC link is connected through the reactor. The real power supply is given by the photovoltaic system for the compensation of power quality problems. The reference current and voltage generation for shunt and series converter is based on phase locked loop and synchronous reference frame theory. The proposed UPQC-CSC design has superior performance for mitigating the power quality problems.

  14. Power quality improvement by unified power quality conditioner based on CSC topology using synchronous reference frame theory.

    Science.gov (United States)

    Dharmalingam, Rajasekaran; Dash, Subhransu Sekhar; Senthilnathan, Karthikrajan; Mayilvaganan, Arun Bhaskar; Chinnamuthu, Subramani

    2014-01-01

    This paper deals with the performance of unified power quality conditioner (UPQC) based on current source converter (CSC) topology. UPQC is used to mitigate the power quality problems like harmonics and sag. The shunt and series active filter performs the simultaneous elimination of current and voltage problems. The power fed is linked through common DC link and maintains constant real power exchange. The DC link is connected through the reactor. The real power supply is given by the photovoltaic system for the compensation of power quality problems. The reference current and voltage generation for shunt and series converter is based on phase locked loop and synchronous reference frame theory. The proposed UPQC-CSC design has superior performance for mitigating the power quality problems.

  15. Power Quality Improvement by Unified Power Quality Conditioner Based on CSC Topology Using Synchronous Reference Frame Theory

    Science.gov (United States)

    Dharmalingam, Rajasekaran; Dash, Subhransu Sekhar; Senthilnathan, Karthikrajan; Mayilvaganan, Arun Bhaskar; Chinnamuthu, Subramani

    2014-01-01

    This paper deals with the performance of unified power quality conditioner (UPQC) based on current source converter (CSC) topology. UPQC is used to mitigate the power quality problems like harmonics and sag. The shunt and series active filter performs the simultaneous elimination of current and voltage problems. The power fed is linked through common DC link and maintains constant real power exchange. The DC link is connected through the reactor. The real power supply is given by the photovoltaic system for the compensation of power quality problems. The reference current and voltage generation for shunt and series converter is based on phase locked loop and synchronous reference frame theory. The proposed UPQC-CSC design has superior performance for mitigating the power quality problems. PMID:25013854

  16. Performance Improvement of a Prefiltered Synchronous-Reference-Frame PLL By Using a PID-Type Loop Filter

    DEFF Research Database (Denmark)

    Golestan, Saeed; Monfared, Mohammad; Frejeido, Francisco

    2014-01-01

    Control Parameters design of a three-phase synchronous reference frame phase locked loop (SRF-PLL) with a pre-filtering stage (acting as the sequence separator) is not a trivial task. The conventional way to deal with this problem is to neglect the interaction between the SRF-PLL and pre-filterin......Control Parameters design of a three-phase synchronous reference frame phase locked loop (SRF-PLL) with a pre-filtering stage (acting as the sequence separator) is not a trivial task. The conventional way to deal with this problem is to neglect the interaction between the SRF-PLL and pre......-filtering stage, and treat them as two separate systems. This approach, although very simple, is not optimum as the pre-filtering stage and the SRF-PLL may have comparable dynamics. The aim of this paper is to develop a systematic and efficient approach to design the control parameters of a SRF-PLL with pre......-integral-derivative controller as the loop filter (instead of the commonly adopted proportionalintegral controller) and arranging a pole-zero cancellation. The suggested method is simple and efficient, and is applicable to the joint operation of different sequence separation techniques and the SRF-PLL. The effectiveness...

  17. Non-linearity of geocenter motion and its impact on the origin of the terrestrial reference frame

    Science.gov (United States)

    Dong, D.; Weijing, Q.; Fang, P.; Peng, D.

    2013-12-01

    Terrestrial reference frame is a cornerstone for modern geodesy and its applications for a wide range of Earth sciences. The underlying assumption is that the motion of the solid Earth's figure center (CF) relative to the mass center (CM) of the Earth system on a multi-decadal time scale is linear. However, past international terrestrial reference frames (ITRFs) showed unexpected trend change in their translation parameters. We investigate the surface mass loading impact on the geocenter variations from atmosphere, ocean, snow, soil moisture, glacier and sea level from 1983 to 2008. The resultant geocenter time series reveal noticeable trend acceleration from 1998 onward, in particular in the z-component. Such a non-linear trend change is statistically significant at the 99% confidence level by the Mann-Kendall (MK) test, and is highly correlated with the Satellite Laser Ranging (SLR) determined translation series. Our study, based on independent geophysical and hydrological models, demonstrates that the observed non-linearity of the Earth-system behavior in the inter-annual time scale has a physical cause, in addition to systematic error from network distribution and analysis procedures, and is able to explain 40% of the disparity between the origins of ITRF2000 and ITRF2005 as well as the good consistency between the origins of ITRF2005 and ITRF2008.

  18. Media Framing

    DEFF Research Database (Denmark)

    Pedersen, Rasmus T.

    2017-01-01

    The concept of media framing refers to the way in which the news media organize and provide meaning to a news story by emphasizing some parts of reality and disregarding other parts. These patterns of emphasis and exclusion in news coverage create frames that can have considerable effects on news...... consumers’ perceptions and attitudes regarding the given issue or event. This entry briefly elaborates on the concept of media framing, presents key types of media frames, and introduces the research on media framing effects....

  19. Design and validation of an open-source library of dynamic reference frames for research and education in optical tracking.

    Science.gov (United States)

    Brown, Alisa; Uneri, Ali; Silva, Tharindu De; Manbachi, Amir; Siewerdsen, Jeffrey H

    2018-04-01

    Dynamic reference frames (DRFs) are a common component of modern surgical tracking systems; however, the limited number of commercially available DRFs poses a constraint in developing systems, especially for research and education. This work presents the design and validation of a large, open-source library of DRFs compatible with passive, single-face tracking systems, such as Polaris stereoscopic infrared trackers (NDI, Waterloo, Ontario). An algorithm was developed to create new DRF designs consistent with intra- and intertool design constraints and convert to computer-aided design (CAD) files suitable for three-dimensional printing. A library of 10 such groups, each with 6 to 10 DRFs, was produced and tracking performance was validated in comparison to a standard commercially available reference, including pivot calibration, fiducial registration error (FRE), and target registration error (TRE). Pivot tests showed calibration error [Formula: see text], indistinguishable from the reference. FRE was [Formula: see text], and TRE in a CT head phantom was [Formula: see text], both equivalent to the reference. The library of DRFs offers a useful resource for surgical navigation research and could be extended to other tracking systems and alternative design constraints.

  20. QUIKVIS- CELESTIAL TARGET AVAILABILITY INFORMATION

    Science.gov (United States)

    Petruzzo, C.

    1994-01-01

    QUIKVIS computes the times during an Earth orbit when geometric requirements are satisfied for observing celestial objects. The observed objects may be fixed (stars, etc.) or moving (sun, moon, planets). QUIKVIS is useful for preflight analysis by those needing information on the availability of celestial objects to be observed. Two types of analyses are performed by QUIKVIS. One is used when specific objects are known, the other when targets are unknown and potentially useful regions of the sky must be identified. The results are useful in selecting candidate targets, examining the effects of observation requirements, and doing gross assessments of the effects of the orbit's right ascension of the ascending node (RAAN). The results are not appropriate when high accuracy is needed (e.g. for scheduling actual mission operations). The observation duration is calculated as a function of date, orbit node, and geometric requirements. The orbit right ascension of the ascending node can be varied to account for the effects of an uncertain launch time of day. The orbit semimajor axis and inclination are constant throughout the run. A circular orbit is assumed, but a simple program modification will allow eccentric orbits. The geometric requirements that can be processed are: 1) minimum separation angle between the line of sight to the object and the earth's horizon; 2) minimum separation angle between the line of sight to the object and the spacecraft velocity vector; 3) maximum separation angle between the line of sight to the object and the zenith direction; and 4) presence of the spacecraft in the earth's shadow. The user must supply a date or date range, the spacecraft orbit and inclination, up to 700 observation targets, and any geometric requirements to be met. The primary output is the time per orbit that conditions are satisfied, with options for sky survey maps, time since a user-specified orbit event, and bar graphs illustrating overlapping requirements. The

  1. Frame of reference of software architecture for web applications and mobile

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Maliza Martinez

    2016-08-01

    Full Text Available Given the need to have a guide for the implementation of informatics applications, and thus achieve automate tasks improving response times of users, designed the framework of reference the architecture software for web and mobile applications with technology free software and open source. The technology to be used is the Object Oriented Programming (OOP with JAVA programming language, a client / server architecture and style of multitier architecture, which will allow us to create scalable, robust and stable systems, together of Java Platform Enterprise Edition (JEE that helps us to implement business applications thanks to the JPA and EJB APIs. By the server for handling transactions, security, scalability and concurrency we have Wildfly application server. And on the client side, for creating graphical interfaces we use the ExtJS and Sencha Touch Framework, which are lightweight, high-performance libraries based on HTML5, JavaScript and CSS3. The report generator is JasperReports, because it has the ability to deliver rich content display and printer. The database engine is MySQL, because its connectivity, speed, and security make it a very appropriate server for access from the web. Finally, as editor of web and mobile applications, we have the integrated development environment Eclipse IDE platform of open source. In this paper we make a critical analysis of such applications and formulate the Framework of Software Architecture for the development and implementation of Web and Mobile Applications, which were implemented in the ECU911 Babahoyo and at the Instituto Tecnologico Superior Babahoyo, proving through its application their effectiveness and efficiency in the implementation of integrated systems

  2. Adjoint-Based Design of Rotors Using the Navier-Stokes Equations in a Noninertial Reference Frame

    Science.gov (United States)

    Nielsen, Eric J.; Lee-Rausch, Elizabeth M.; Jones, William T.

    2010-01-01

    Optimization of rotorcraft flowfields using an adjoint method generally requires a time-dependent implementation of the equations. The current study examines an intermediate approach in which a subset of rotor flowfields are cast as steady problems in a noninertial reference frame. This technique permits the use of an existing steady-state adjoint formulation with minor modifications to perform sensitivity analyses. The formulation is valid for isolated rigid rotors in hover or where the freestream velocity is aligned with the axis of rotation. Discrete consistency of the implementation is demonstrated by using comparisons with a complex-variable technique, and a number of single- and multipoint optimizations for the rotorcraft figure of merit function are shown for varying blade collective angles. Design trends are shown to remain consistent as the grid is refined.

  3. The role of scene type and priming in the processing and selection of a spatial frame of reference

    Directory of Open Access Journals (Sweden)

    Katrin eJohannsen

    2013-04-01

    Full Text Available The selection and processing of a spatial frame of reference (FOR in interpreting verbal scene descriptions is of great interest to psycholinguistics. In this study, we focus on the choice between the relative and the intrinsic FOR, addressing two questions: a does the presence or absence of a background in the scene influence the selection of a FOR, and b what is the effect of a previously selected FOR on the subsequent processing of a different FOR. Our results show that if a scene includes a realistic background, this will make the selection of the relative FOR more likely. We attribute this effect to the facilitation of mental simulation, which enhances the relation between the viewer and the objects. With respect to the response accuracy, we found both a higher (due to FOR priming and a lower accuracy (due to different FOR, while for the response latencies, we only found a delay effect.

  4. Improved fault ride through capability of DFIG based wind turbines using synchronous reference frame control based dynamic voltage restorer.

    Science.gov (United States)

    Rini Ann Jerin, A; Kaliannan, Palanisamy; Subramaniam, Umashankar

    2017-09-01

    Fault ride through (FRT) capability in wind turbines to maintain the grid stability during faults has become mandatory with the increasing grid penetration of wind energy. Doubly fed induction generator based wind turbine (DFIG-WT) is the most popularly utilized type of generator but highly susceptible to the voltage disturbances in grid. Dynamic voltage restorer (DVR) based external FRT capability improvement is considered. Since DVR is capable of providing fast voltage sag mitigation during faults and can maintain the nominal operating conditions for DFIG-WT. The effectiveness of the DVR using Synchronous reference frame (SRF) control is investigated for FRT capability in DFIG-WT during both balanced and unbalanced fault conditions. The operation of DVR is confirmed using time-domain simulation in MATLAB/Simulink using 1.5MW DFIG-WT. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  5. An elementary survey of celestial mechanics

    CERN Document Server

    Ryabov, Y

    2006-01-01

    An accessible exposition of gravitation theory and celestial mechanics, this classic, oft-cited work was written by a distinguished Soviet astronomer. It explains with exceptional clarity the methods used by physicists in studying celestial phenomena.A historical introduction explains the Ptolemaic view of planetary motion and its displacement by the studies of Copernicus, Kepler, and Newton. Succeeding chapters examine the making of celestial observations and measurements and explain such central concepts as the ecliptic, the orbital plane, the two- and three-body problems, and perturbed moti

  6. Celestial mechanics of planet shells

    Science.gov (United States)

    Barkin, Yu V.; Vilke, V. G.

    2004-06-01

    The motion of a planet consisting of an external shell (mantle) and a core (rigid body), which are connected by a visco-elastic layer and mutually gravitationally interact with each other and with an external celestial body (considered as a material point), is studied (Barkin, 1999, 2002a,b; Vilke, 2004). Relative motions of the core and mantle are studied on the assumption that the centres of mass of the planet and external body move on unperturbed Keplerian orbits around the general centre of mass of the system. The core and mantle of the planet have axial symmetry and have different principal moments of inertia. The differential action of the external body on the core and mantle cause the periodic relative displacements of their centres of mass and their relative turns. An approximate solution of the problem was obtained on the basis of the linearization, averaging and small-parameter methods. The obtained analytical results are applied to the study of the possible relative displacements of the core and mantle of the Earth under the gravitational action of the Moon. For the suggested two-body Earth model and in the simple case of a circular (model) lunar orbit the new phenomenon of periodic translatory-rotary oscillations of the core with a fortnightly period the mantle was observed. The more remarkable phenomenon is the cyclic rotation with the same period (13.7 days) of the core relative to the mantle with a ‘large’ amplitude of 152 m (at the core surface).The results obtained confirm the general concept described by Barkin (1999, 2002a,b) that induced relative shell oscillations can control and dictate the cyclic and secular processes of energization of the planets and satellites in definite rhythms and on different time scales.The results obtained mean that giant moments and forces produce energy which causes in particular deformations of the viscoelastic layer between planet shells. This process is realized with different intensities on different time

  7. Celestial mechanics the waltz of the planets

    CERN Document Server

    Celletti, Alessandra

    2007-01-01

    The aim of this book is to demonstrate to a wider audience, as well as to a more skilled audience, the many fascinating aspects of modern celestial mechanics. It sets out to do this without the use of mathematics.

  8. Are pedicle screw perforation rates influenced by distance from the reference frame in multilevel registration using a computed tomography-based navigation system in the setting of scoliosis?

    Science.gov (United States)

    Uehara, Masashi; Takahashi, Jun; Ikegami, Shota; Kuraishi, Shugo; Shimizu, Masayuki; Futatsugi, Toshimasa; Oba, Hiroki; Kato, Hiroyuki

    2017-04-01

    Pedicle screw fixation is commonly employed for the surgical correction of scoliosis but carries a risk of serious neurovascular or visceral structure events during screw insertion. To avoid these complications, we have been using a computed tomography (CT)-based navigation system during pedicle screw placement. As this could also prolong operation time, multilevel registration for pedicle screw insertion for posterior scoliosis surgery was developed to register three consecutive vertebrae in a single time with CT-based navigation. The reference frame was set either at the caudal end of three consecutive vertebrae or at one or two vertebrae inferior to the most caudal registered vertebra, and then pedicle screws were inserted into the three consecutive registered vertebrae and into the one or two adjacent vertebrae. This study investigated the perforation rates of vertebrae at zero, one, two, three, or four or more levels above or below the vertebra at which the reference frame was set. This is a retrospective, single-center, single-surgeon study. One hundred sixty-one scoliosis patients who had undergone pedicle screw fixation were reviewed. Screw perforation rates were evaluated by postoperative CT. We evaluated 161 scoliosis patients (34 boys and 127 girls; mean±standard deviation age: 14.6±2.8 years) who underwent pedicle screw fixation guided by a CT-based navigation system between March 2006 and December 2015. A total of 2,203 pedicle screws were inserted into T2-L5 using multilevel registration with CT-based navigation. The overall perforation rates for Grade 1, 2, or 3, Grade 2 or 3 (major perforations), and Grade 3 perforations (violations) were as follows: vertebrae at which the reference frame was set: 15.9%, 6.1%, and 2.5%; one vertebra above or below the reference frame vertebra: 16.5%, 4.0%, and 1.2%; two vertebrae above or below the reference frame vertebra: 20.7%, 8.7%, and 2.3%; three vertebrae above or below the reference frame vertebra: 23

  9. The Internal/External Frame of Reference Model Revisited: Incorporating General Cognitive Ability and General Academic Self-Concept.

    Science.gov (United States)

    Brunner, Martin; Lüdtke, Oliver; Trautwein, Ulrich

    2008-01-01

    The internal/external frame of reference model (I/E model; Marsh, 1986 ) is a highly influential model of self-concept formation, which predicts that domain-specific abilities have positive effects on academic self-concepts in the corresponding domain and negative effects across domains. Investigations of the I/E model do not typically incorporate general cognitive ability or general academic self-concept. This article investigates alternative measurement models for domain-specific and domain-general cognitive abilities and academic self-concepts within an extended I/E model framework using representative data from 25,301 9th-grade students. Empirical support was found for the external validity of a new measurement model for academic self-concepts with respect to key student characteristics (gender, school satisfaction, educational aspirations, domain-specific interests, grades). Moreover, the basic predictions of the I/E model were confirmed, and the new extension of the traditional I/E model permitted meaningful relations to be drawn between domain-general cognitive ability and domain-general academic self-concept as well as between the domain-specific elements of the model.

  10. Modified Synchronous Reference Frame Based Shunt Active Power Filter with Fuzzy Logic Control Pulse Width Modulation Inverter

    Directory of Open Access Journals (Sweden)

    Suleiman Musa

    2017-05-01

    Full Text Available Harmonic distortion in power networks has greatly reduced power quality and this affects system stability. In order to mitigate this power quality issue, the shunt active power filter (SAPF has been widely applied and it is proven to be the best solution to current harmonics. This paper evaluates the performance of the modified synchronous reference frame extraction (MSRF algorithm with fuzzy logic controller (FLC based current control pulse width modulation (PWM inverter of three-phase three-wire SAPF to mitigate current harmonics. The proposed FLC is designed with a reduced amount of membership functions (MFs and rules, and thus significantly reduces the computational time and memory size. Modeling and simulations of SAPF are carried out using MATLAB/Simulink R2012a with the power system toolbox under steady-state condition, and this is followed with hardware implementation using a TMS320F28335 digital signal processor (DSP, Specrum Digital Inc., Stafford, TX, USA. The results obtained demonstrate a good and satisfactory response to mitigate the harmonics in the system. The total harmonic distortion (THD for the system has been reduced from 25.60% to 0.92% and 1.41% in the simulation study with and without FLC, respectively. Similarly for the experimental study, the SAPF can compensate for the three-phase load current by reducing THD to 5.07% and 7.4% with and without FLC, respectively.

  11. Safety Management. An Introduction to a Frame of Reference Exemplified with Case Studies from Non-Nuclear Contexts

    International Nuclear Information System (INIS)

    Svensson, Ola; Salo, Ilkka

    2004-11-01

    A systems perspective on safety management is introduced followed by two briefly presented case studies of safety management in non-nuclear contexts. The first study concerns a car manufacturer and the second study a road traffic tunnel system. The risks of a car accident in the first case study are evident. The great exposure generates many incidents and accidents. In the second study, the rather low traffic intensity through the tunnel produces few incidents and accidents and only a few fatal accidents over the years. Yet, the risk of the individual traveler is much greater in the tunnel than on the average road. The case studies are presented in a systems perspective with emphasis on information feedback about the risks of the systems. The first case study illustrates high quality safety management, while the second case study shows many weaknesses of the safety management in the tunnel system. Some differences in safety management between the case studies are noted. The last part of the study presents an organizational perspective on safety management and offers alternative theoretical perspectives on the concept of safety management. The report shows that further studies are needed both (1) to develop a frame of reference for describing safety management across industries and activities and (2) to collect data illustrating of good and poor safety management. Then, the results can be used to strengthen and/or improving safety management in the nuclear power industry and its regulators

  12. Safety Management. An Introduction to a Frame of Reference Exemplified with Case Studies from Non-Nuclear Contexts

    Energy Technology Data Exchange (ETDEWEB)

    Svensson, Ola (Risk Analysis, Social and Decision Research Unit, Dept. of Psychology, Stockholm Univ., Stockholm (Sweden)); Salo, Ilkka (Dept. of Psychology, Lund Univ., Lund (Sweden))

    2004-11-15

    A systems perspective on safety management is introduced followed by two briefly presented case studies of safety management in non-nuclear contexts. The first study concerns a car manufacturer and the second study a road traffic tunnel system. The risks of a car accident in the first case study are evident. The great exposure generates many incidents and accidents. In the second study, the rather low traffic intensity through the tunnel produces few incidents and accidents and only a few fatal accidents over the years. Yet, the risk of the individual traveler is much greater in the tunnel than on the average road. The case studies are presented in a systems perspective with emphasis on information feedback about the risks of the systems. The first case study illustrates high quality safety management, while the second case study shows many weaknesses of the safety management in the tunnel system. Some differences in safety management between the case studies are noted. The last part of the study presents an organizational perspective on safety management and offers alternative theoretical perspectives on the concept of safety management. The report shows that further studies are needed both (1) to develop a frame of reference for describing safety management across industries and activities and (2) to collect data illustrating of good and poor safety management. Then, the results can be used to strengthen and/or improving safety management in the nuclear power industry and its regulators

  13. Cognitive ability, academic achievement and academic self-concept: extending the internal/external frame of reference model.

    Science.gov (United States)

    Chen, Ssu-Kuang; Hwang, Fang-Ming; Yeh, Yu-Chen; Lin, Sunny S J

    2012-06-01

    Marsh's internal/external (I/E) frame of reference model depicts the relationship between achievement and self-concept in specific academic domains. Few efforts have been made to examine concurrent relationships among cognitive ability, achievement, and academic self-concept (ASC) within an I/E model framework. To simultaneously examine the influences of domain-specific cognitive ability and grades on domain self-concept in an extended I/E model, including the indirect effect of domain-specific cognitive ability on domain self-concept via grades. Tenth grade respondents (628 male, 452 female) to a national adolescent survey conducted in Taiwan. Respondents completed surveys designed to measure maths and verbal aptitudes. Data on Maths and Chinese class grades and self-concepts were also collected. Statistically significant and positive path coefficients were found between cognitive ability and self-concept in the same domain (direct effect) and between these two constructs via grades (indirect effect). The cross-domain effects of either ability or grades on ASC were negatively significant. Taiwanese 10th graders tend to evaluate their ASCs based on a mix of ability and achievement, with achievement as a mediator exceeding ability as a predictor. In addition, the cross-domain effects suggest that Taiwanese students are likely to view Maths and verbal abilities and achievements as distinctly different. ©2011 The British Psychological Society.

  14. Methods of Celestial Mechanics Volume II: Application to Planetary System, Geodynamics and Satellite Geodesy

    CERN Document Server

    Beutler, Gerhard

    2005-01-01

    G. Beutler's Methods of Celestial Mechanics is a coherent textbook for students as well as an excellent reference for practitioners. Volume II is devoted to the applications and to the presentation of the program system CelestialMechanics. Three major areas of applications are covered: (1) Orbital and rotational motion of extended celestial bodies. The properties of the Earth-Moon system are developed from the simplest case (rigid bodies) to more general cases, including the rotation of an elastic Earth, the rotation of an Earth partly covered by oceans and surrounded by an atmosphere, and the rotation of an Earth composed of a liquid core and a rigid shell (Poincaré model). (2) Artificial Earth Satellites. The oblateness perturbation acting on a satellite and the exploitation of its properties in practice is discussed using simulation methods (CelestialMechanics) and (simplified) first order perturbation methods. The perturbations due to the higher-order terms of the Earth's gravitational potential and reso...

  15. The Internal/External Frame of Reference Model of Self-Concept and Achievement Relations: Age-Cohort and Cross-Cultural Differences

    Science.gov (United States)

    Marsh, Herbert W.; Abduljabbar, Adel Salah; Parker, Philip D.; Morin, Alexandre J. S.; Abdelfattah, Faisal; Nagengast, Benjamin; Möller, Jens; Abu-Hilal, Maher M.

    2015-01-01

    The internal/external frame of reference (I/E) model and dimensional comparison theory posit paradoxical relations between achievement (ACH) and self-concept (SC) in mathematics (M) and verbal (V) domains; ACH in each domain positively affects SC in the matching domain (e.g., MACH to MSC) but negatively in the nonmatching domain (e.g., MACH to…

  16. The Internal/External Frame of Reference of Academic Self-Concept: Extension to a Foreign Language and the Role of Language of Instruction

    Science.gov (United States)

    Xu, Man K.; Marsh, Herbert W.; Hau, Kit-Tai; Ho, Irene T.; Morin, Alexandre J. S.; Abduljabbar, Adel S.

    2013-01-01

    The internal/external frame of reference (I/E) model (Marsh, 1986) posits that the effects of contrasting math and verbal domains of achievement are positive for matching academic self-concepts (ASCs) but negative for nonmatching ASCs (i.e., math achievement on verbal ASC; verbal achievement on math ASC). We extend the classic I/E model by…

  17. Explaining Paradoxical Relations Between Academic Self-Concepts and Achievements: Cross-Cultural Generalizability of the Internal/External Frame of Reference Predictions Across 26 Countries

    Science.gov (United States)

    Marsh, Herbert W.; Hau, Kit-Tai

    2004-01-01

    The internal/external frame of reference (I/E) model explains a seemingly paradoxical pattern of relations between math and verbal self-concepts and corresponding measures of achievement, extends social comparison theory, and has important educational implications. In a cross-cultural study of nationally representative samples of 15-year-olds from…

  18. The role of rat posterior parietal cortex in coordinating spatial representations during place avoidance in dissociated reference frames on a continuously rotating arena (Carousel)

    Czech Academy of Sciences Publication Activity Database

    Svoboda, Jan; Telenský, Petr; Blahna, Karel; Vodička, Martin; Stuchlík, Aleš

    2015-01-01

    Roč. 292, Oct 1 (2015), s. 1-9 ISSN 0166-4328 R&D Projects: GA ČR(CZ) GA14-03627S Institutional support: RVO:67985823 Keywords : posterior parietal cortex * reference frame * navigation * lesion * rat Subject RIV: FH - Neurology Impact factor: 3.002, year: 2015

  19. Extension of the Internal/External Frame of Reference Model of Self-Concept Formation: Importance of Native and Nonnative Languages for Chinese Students.

    Science.gov (United States)

    Marsh, Herbert W.; Kong, Chit-Kwong; Hau, Kit-Tai

    2001-01-01

    Extended the internal/external frame of reference (I/E) model of self-concept formation by relating Chinese, English, and math achievement to Chinese, English, and math self-concepts in a five year longitudinal study based on a large representative sample of Hong Kong high school students. (Author)

  20. Celestial Navigation in the 21st Century

    Science.gov (United States)

    Kaplan, George H.

    2014-05-01

    Despite the ubiquity of GPS receivers in modern life for both timekeeping and geolocation, other forms of navigation remain important because of the weakness of the GPS signals (and those from similar sat-nav systems) and the ease with which they can be jammed. GPS jammers are available for sale on the Internet. The defense and civil aviation communities are particularly concerned about “GPS denial”, whether intentional or accidental, during critical operations.Automated star trackers for navigation have been available since the 1950s. Modern compact observing systems, operating in the far-red and near-IR bands, can detect useful numbers of stars even in the daytime at sea level. A capability to measure the directions of stars relative to some local set of coordinate axes is advantageous for many types of vehicles, whether on the ground, at sea, in the air, or in space, because it provides a direct connection to the inertial reference system represented by current star catalogs. Such a capability can yield precise absolute orientation information not available in any other way. Automated celestial observing systems can be effectively coupled to inertial navigation systems (INS), providing “truth” data for constraining the drift in the INS navigation solution, even if stellar observations are not continuously available due to weather. However, obtaining precise latitude and longitude from stellar observations alone, on a moving platform, remains a challenge, because it requires a determination of the direction to the center of the Earth, i.e., the gravity vertical. General relativity tells us that on-board (“lab”) measurements cannot separate the acceleration of gravity from the acceleration of the platform. Various schemes for overcoming this fundamental problem have been used in the past, at low accuracy, and better ones have been proposed for modern applications. This paper will review some recent developments in this rapidly advancing field.

  1. Oscillatory activity reflects differential use of spatial reference frames by sighted and blind individuals in tactile attention.

    Science.gov (United States)

    Schubert, Jonathan T W; Buchholz, Verena N; Föcker, Julia; Engel, Andreas K; Röder, Brigitte; Heed, Tobias

    2015-08-15

    Touch can be localized either on the skin in anatomical coordinates, or, after integration with posture, in external space. Sighted individuals are thought to encode touch in both coordinate systems concurrently, whereas congenitally blind individuals exhibit a strong bias for using anatomical coordinates. We investigated the neural correlates of this differential dominance in the use of anatomical and external reference frames by assessing oscillatory brain activity during a tactile spatial attention task. The EEG was recorded while sighted and congenitally blind adults received tactile stimulation to uncrossed and crossed hands while detecting rare tactile targets at one cued hand only. In the sighted group, oscillatory alpha-band activity (8-12Hz) in the cue-target interval was reduced contralaterally and enhanced ipsilaterally with uncrossed hands. Hand crossing attenuated the degree of posterior parietal alpha-band lateralization, indicating that attention deployment was affected by external spatial coordinates. Beamforming suggested that this posture effect originated in the posterior parietal cortex. In contrast, cue-related lateralization of central alpha-band as well as of beta-band activity (16-24Hz) were unaffected by hand crossing, suggesting that these oscillations exclusively encode anatomical coordinates. In the blind group, central alpha-band activity was lateralized, but did not change across postures. The pattern of beta-band activity was indistinguishable between groups. Because the neural mechanisms for posterior alpha-band generation seem to be linked to developmental vision, we speculate that the lack of this neural mechanism in blind individuals is related to their preferred use of anatomical over external spatial codes in sensory processing. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Effects on Chilean Vertical Reference Frame due to the Maule Earthquake co-seismic and post-seismic effects

    Science.gov (United States)

    Montecino, Henry D.; de Freitas, Silvio R. C.; Báez, Juan C.; Ferreira, Vagner G.

    2017-12-01

    The Maule Earthquake (Mw = 8.8) of February 27, 2010 is among the strongest earthquakes that occurred in recent years throughout the world. The crustal deformation caused by this earthquake has been widely studied using GNSS, InSAR and gravity observations. However, there is currently no estimation of the possible vertical deformations produced by co-seismic and post-seismic effects in segments of the Chilean Vertical Reference Frame (CHVRF). In this paper, we present an estimation of co-seismic and post-seismic deformations on the CHVRF using an indirect approach based on GNSS and Gravity Recovery and Climate Experiment (GRACE) data as well as by applying a trajectory model. GNSS time series were used from 10 continuous GNSS stations in the period from 2007 to 2015, as well as 28 GNSS temporary stations realized before and after the earthquake, and 34 vertical deformation vectors in the region most affected by the earthquake. We considered a set of 147 monthly solutions of spherical harmonic gravity field that were expanded up to degree, as well as order 96 of the GRACE mission provided by Center for Space Research, University of Texas at Austin (UT-CSR) process center. The magnitude of vertical deformation was estimated in part of the Chilean vertical network due to the co-seismic and post-seismic effects. Once we evaluated the hydrological effect, natural and artificial jumps, and the effect of glacial isostatic adjustment in GNSS and GRACE time series, the maximum values associated to co- and post-seismic deformations on orthometric height were found to be ∼-34 cm and 5 cm, respectively. Overall, the deformation caused by the Maule earthquake in orthometric heights is almost entirely explained by the variation in the ellipsoidal heights (over 85% in co-seismic jump); however, coseismic jump in the geoid reached -3.3 mm, and could influence the maintenance of a modern vertical reference network in a medium to long term. We evaluated the consistency for a

  3. International project PHOBOS - Experiment 'Celestial Mechanics'

    Science.gov (United States)

    Kolyuka, Yu. F.; Kudryavtsev, S. M.; Tarasov, V. P.; Tikhonov, V. F.; Ivanov, N. M.; Polyakov, V. S.; Potchukaev, V. N.; Papkov, O. V.; Sukhanov, K. G.; Akim, E. L.; Stepanians, V. A.; Nasirov, R. R.

    1991-02-01

    Scientific results in the area of celestial mechanics obtained during the control process of the Phobos 2 spacecraft flight are presented. A brief description of the space flight profile is given and the orbit parameters are provided. The bases of the navigation support are discussed and it is noted that both the navigation support and the experiment combined the efforts of Glavcosmos, Intercosmos, NASA, CNES, ESOC, and the leading specialists in celestial mechanics and astrometry from different scientific institutions of many countries. A new theory is presented which describes the motion of Martian moons and the determination of the Phobos gravitational constant.

  4. Relativistic Celestial Mechanics of the Solar System

    CERN Document Server

    Kopeikin, Sergei; Kaplan, George

    2011-01-01

    This authoritative book presents the theoretical development of gravitational physics as it applies to the dynamics of celestial bodies and the analysis of precise astronomical observations. In so doing, it fills the need for a textbook that teaches modern dynamical astronomy with a strong emphasis on the relativistic aspects of the subject produced by the curved geometry of four-dimensional spacetime. The first three chapters review the fundamental principles of celestial mechanics and of special and general relativity. This background material forms the basis for understanding relativistic r

  5. BATING A REFERENCE INSTALLATION BASED ON CONTROLLED-POTENTIAL COULOMETRY METOD IN THE FRAME OF IMPROVING THE STATE PRIMARY STANDARD GET 176 AND ITS MEASUREMENT CAPABILITIES

    Directory of Open Access Journals (Sweden)

    V. M. Zyskin

    2016-01-01

    Full Text Available The results of developing of reference installation, based on a controlled-potential coulometry, in the frame of improving the State primary standard of the units of mass (molar fraction and mass (molar concentration of a component in the liquid and solid substances and materials GET 176 are presented. The physical principles of controlled-potential coulometry, content and metrological characteristics of the developed installation are considered. Measurement results of copper, iron and lead contents in the certified reference materials of metals' solutions and CRM of brass produced by BAM, Germany, obtained using reference installation are given.

  6. Dynamics of Natural and Artificial Celestial Bodies

    Science.gov (United States)

    Pretka-Ziomek, Halina; Wnuk, Edwin; Seidelmann, P. Kenneth; Richardson, David.

    2002-01-01

    This volume contains papers presented at the US/European Celestial Mechanics Workshop organized by the Astronomical Observatory of Adam Mickiewicz University in Poznan, Poland and held in Poznan, from 3 to 7 July 2000. The purpose of the workshop was to identify future research in celestial mechanics and astrometry and encourage collaboration among scientists from eastern and western countries. Also an emphasis was placed on attracting young members of the fields from around the world and encouraging them to undertake new research efforts needed for advancements in those fields. There was a full program of invited and contributed presentations on selected subjects and each day ended with a discussion period on a general subject in celestial mechanics. The discussion topics and the leaders were: Resonances and Chaos -- A. Morbidelli; Artificial Satellite Orbits -- K.T. Alfriend; Near Earth Objects -- K. Muinonen; Small Solar System Bodies -- I. Williams; and Summary -- P.K. Seidelmann. The goal of the discussions was to identify what we did not know and how we might further our knowledge. It was felt, in addition, that Poznan, Poland, with a core of scientists covering a range of ages, would provide an example of how a research and educational group could be developed elsewhere. Also, Poznan is a central location convenient to eastern and western countries. Thus, the gathering of people and the papers presented are to be the bases for building the future of astrometry and celestial mechanics. Link: http://www.wkap.nl/prod/b/1-4020-0115-0

  7. Celestial Navigation on the Surface of Mars

    Science.gov (United States)

    Malay, Benjamin P.

    2001-05-01

    A simple, accurate, and autonomous method of finding position on the surface of Mars currently does not exist. The goal of this project is to develop a celestial navigation process that will fix a position on Mars with 100-meter accuracy. This method requires knowing the position of the stars and planets referenced to the Martian surface with one arcsecond accuracy. This information is contained in an ephemeris known as the Aeronautical Almanac (from Ares, the god of war) . Naval Observatory Vector Astrometry Subroutines (NOVAS) form the basis of the code used to generate the almanac. Planetary position data come the JPL DE405 Planetary Ephemeris. The theoretical accuracy of the almanac is determined mathematically and compared with the Ephemeris for Physical Observations of Mars contained in the Astronautical Almanac. A preliminary design of an autonomous celestial navigation system is presented. Recommendations of how to integrate celestial navigation into NASA=s current Mars exploration program are also discussed. This project is a useful and much-needed first step towards establishing celestial navigation as a practical way to find position on the surface of Mars.

  8. Multiple reference frames in neglect? An investigation of the object-centred frame and the dissociation between "near" and "far" from the body by use of a mirror.

    Science.gov (United States)

    Laeng, Bruno; Brennen, Tim; Johannessen, Kristin; Holmen, Kirsti; Elvestad, Rolf

    2002-09-01

    In this single case study of a man (AE) who suffered a right hemisphere stroke we showed the co-existence of neglect within different spatial frames: (a) In left hemispace and (b) in 'far' versus 'near' space, both as defined from the patient's viewpoint, as well as (c) for the left side of an object (as defined from an object-centred view). In the experiment, AE's latencies to name the colour of two cubes, each located in one hemispace, were measured. In some conditions, the cubes were placed on a table but in other conditions each cube was held in one hand of an experimenter who could either face the patient or show the cubes while her back was turned towards him. One prediction was that AE would show longer latencies for cubes in left hemispace; however, if object-centred neglect also occurred, then latencies should be even longer for cubes held in the experimenter's left hand. In order to reveal the presence of neglect for 'far' versus 'near' space, the cubes could also be positioned either near to (i.e. reaching distance) or far from the patient (i.e., several metres out of reach), by moving the table or the experimenter. Finally, in some conditions, AE looked at the cubes into a mirror that was positioned far away from his body. Because external objects seen in a mirror can be 'near' the patient's body, the patient actually looked at a 'far' location (i.e. the surface of the mirror) to see an object that is 'near'. The experiment confirmed the presence of all forms of neglect, since AE not only named the colour of a cube seen in his left hemispace more slowly than in right hemispace, but latencies increased for a cube held by the experimenter in her left hand and in left hemispace (both when the left hand was seen directly or as a mirror reflection). Finally, AE's performance was worse for 'far' than 'near' locations, when the cubes were physically located near his body (i.e., within "grasping" space) but seen in the mirror.

  9. A radio optical reference frame. I. Precise radio source positions determined by Mark III VLBI - Observations from 1979 to 1988 and a tie to the FK5

    International Nuclear Information System (INIS)

    Ma, C.; Shaffer, D.B.; De Vegt, C.; Johnston, K.J.; Russell, J.L.

    1990-01-01

    Observations from 600 Mark III VLBI experiments from 1979 to 1988, resulting in 237,681 acceptable pairs of group delay and phase delay rate observations, have been used to derive positions of 182 extragalactic radio sources with typical formal standard errors less than 1 mas. The sources are distributed fairly evenly above delta = -30 deg, and 70 sources have delta greater than 0 deg. Analysis with different troposphere models, as well as internal and external comparisons, indicates that a coordinate frame defined by this set of radio sources should be reliable at the 1 mas level. The right ascension zero point of this reference frame has been aligned with the FK5 by using the optical positions of 28 extragalactic radio sources whose positions are on the FK5 system. Because of known defects in the knowledge of astronomical constants, daily nutation offsets in longitude and obliquity were determined relative to an arbitrary reference day in the set of experiments. 30 refs

  10. Relations between Temperament and Metacognition and Frames of Reference in Behaviors in Public Situations in Early and Middle Adolescence: An Analysis of Age Stages

    Directory of Open Access Journals (Sweden)

    Nana Kanzaki

    2018-02-01

    Full Text Available We conducted a questionnaire survey using a cross-sectional sample of early and middle adolescents aged 10–15 (n = 351 in order to investigate relationships between temperament, metacognition, and frames of reference in behaviors in public situations. The sample was divided into two groups by age (ear group: 10–12; middle-adolescence group: 13–15 and were analyzed by Multiple Group Structural Equation Modeling. Explanatory variables were four components of temperament [effortful control (EfC, affiliativeness (Afil, surgency (Sur, and negative affect (NgA] and metacognition. Objective variables were three components of frames of reference in behaviors in public situations [egocentrism (Ego, neighborhood evaluation (Nei, and public values (Pub]. In both age groups, EfC had a negative effect on Ego, and Sur had a negative effect on Nei. However, only in the middle-adolescence group did Afil and NgA have significant effects on Pub. Meanwhile, metacognition in the ear group had a positive effect on Ego and Nei, but these relations disappeared in the middle-adolescence group, and only in the middle-adolescence group did metacognition have a positive effect on Pub. We discuss frames of reference in behaviors in public situations from the viewpoint of the development of social cognition in early and middle adolescence in relation to temperament and metacognition.

  11. Recent advances in celestial and space mechanics

    CERN Document Server

    Chyba, Monique

    2016-01-01

    This book presents recent advances in space and celestial mechanics, with a focus on the N-body problem and astrodynamics, and explores the development and application of computational techniques in both areas. It highlights the design of space transfers with various modes of propulsion, like solar sailing and low-thrust transfers between libration point orbits, as well as a broad range of targets and applications, like rendezvous with near Earth objects. Additionally, it includes contributions on the non-integrability properties of the collinear three- and four-body problem, and on general conditions for the existence of stable, minimum energy configurations in the full N-body problem. A valuable resource for physicists and mathematicians with research interests in celestial mechanics, astrodynamics and optimal control as applied to space transfers, as well as for professionals and companies in the industry.

  12. Gravity in Gravity’s Rainbow – Force, Fictitious Force, and Frame of Reference; or: The Science and Poetry of Sloth

    Directory of Open Access Journals (Sweden)

    Nina Engelhardt

    2014-09-01

    Full Text Available Gravity is a prominent physical concept in 'Gravity's Rainbow', as already announced by the novel's title. If the second part of the title – the poetic image of the rainbow – is bound up with mathematical formulas and the parabolic path of the Rocket, so conversely, this paper argues, Pynchon's novel introduces a relation between gravity and fiction. The paper explores 'Gravity's Rainbow''s use of the changing historical understandings of gravitation from the seventeenth to the twentieth centuries by examining the novel's illustration of Newton and Leibniz's opposed concepts as well as its references to gravity as understood in Einstein's theory of relativity. When tracing the notions of gravity as force, fictitious force, and frame of reference, a particular focus lies on the relation of physical imagery to ethical questions and on the way 'Gravity's Rainbow' provides a physico-ethical explanation of Slothrop's disappearance from the novel.

  13. Celestial positioning method based on centroid correction of STAR trajectory

    Science.gov (United States)

    Liu, Dianjian; Zhang, Zhili; Zhou, Zhaofa; Zhao, Junyang; Liu, Xianyi

    2017-05-01

    In order to reduce the position deviations between the centroid extracted from the star points and the actual centroid and reduce the influence of coarse errors contained in the astronomical information of star calculation on astronomical positioning accuracy of the digital zenith equipment, an astronomical locating method to correct star centroid location is proposed. Based on the star trajectory equation obtained from the imaging model of the starimage pointson the image plane of the zenith equipment, the center-of-mass centroid trajectory parameters are obtained by least-square method with the information of star point centroid position extracted from the multi-frame star images shot at the same observation station, which is used to identify the theoretical centroid position and correct the original centroid position, so as to participate in the astronomical positioning solution. For the simulation star map of gaussian white noise with distribution n (0, 52), after the centroid correction, the accuracy of the longitude of the astronomical rectangle is improved by 0.058″, the latitude improvement by 0.176″ to the mostand the position of the satellite by about 5m. Experimental results show that this method has good applicability, which can improve the celestial position accuracy of digital zenith equipment effectively.

  14. Framing the frame

    Directory of Open Access Journals (Sweden)

    Todd McElroy

    2007-08-01

    Full Text Available We examined how the goal of a decision task influences the perceived positive, negative valence of the alternatives and thereby the likelihood and direction of framing effects. In Study 1 we manipulated the goal to increase, decrease or maintain the commodity in question and found that when the goal of the task was to increase the commodity, a framing effect consistent with those typically observed in the literature was found. When the goal was to decrease, a framing effect opposite to the typical findings was observed whereas when the goal was to maintain, no framing effect was found. When we examined the decisions of the entire population, we did not observe a framing effect. In Study 2, we provided participants with a similar decision task except in this situation the goal was ambiguous, allowing us to observe participants' self-imposed goals and how they influenced choice preferences. The findings from Study 2 demonstrated individual variability in imposed goal and provided a conceptual replication of Study 1. %need keywords

  15. Foldable Frame Supporting Electromagnetic Radiation Collectors

    DEFF Research Database (Denmark)

    2011-01-01

    The present invention relates to flexible frames supporting electromagnetic radiation collectors, such as antennas, antenna reflectors, deflectors or solar collectors, for celestial or terrestrial applications, which can be folded to be stored and/or transported. The method for stowing deforms...

  16. Global VLBI Observations of Weak Extragalactic Radio Sources: Imaging Candidates to Align the VLBI and Gaia Frames

    Science.gov (United States)

    Bourda, Geraldine; Collioud, Arnaud; Charlot, Patrick; Porcas, Richard; Garrington, Simon

    2010-01-01

    The space astrometry mission Gaia will construct a dense optical QSO-based celestial reference frame. For consistency between optical and radio positions, it will be important to align the Gaia and VLBI frames (International Celestial Reference Frame) with the highest accuracy. In this respect, it is found that only 10% of the ICRF sources are suitable to establish this link (70 sources), either because most of the ICRF sources are not bright enough at optical wavelengths or because they show extended radio emission which precludes reaching the highest astrometric accuracy. In order to improve the situation, we initiated a multi-step VLBI observational project, dedicated to finding additional suitable radio sources for aligning the two frames. The sample consists of about 450 optically-bright radio sources, typically 20 times weaker than the ICRF sources, which have been selected by cross-correlating optical and radio catalogs. The initial observations, aimed at checking whether these sources are detectable with VLBI, and conducted with the European VLBI Network (EVN) in 2007, showed an excellent 90% detection rate. This paper reports on global VLBI observations carried out in March 2008 to image 105 from the 398 previously detected sources. All sources were successfully imaged, revealing compact VLBI structure for about half of them, which is very promising for the future.

  17. Horizontal and vertical crustal movements from three-dimensional very long baseline interferometry kinematic reference frame: Implication for the reversal timescale revision

    Science.gov (United States)

    Heki, Kosuke

    Three-dimensional kinematic reference frame of geodetic very long baseline interferometry (VLBI) stations, tied to a geologic plate motion model, was established using the GLB907 solution by first selecting globally distributed stable plate interior stations and then applying a small translation and a rotation for the entire network in a three-dimensional space so that the differences in the ``horizontal'' velocities between the VLBI observations and the model predictions are minimized. Since the VLBI network is global, we only assume that the horizontal movements of tectonically stable stations obey a plate motion model; we need not introduce any unwarranted constraints to the vertical velocities of specific stations to realize the frame. A suggestive correlation was found between the estimated vertical velocities of North American stations and those predicted by a postglacial rebound model. The revision of the magnetic polarity timescale (MPTS) causes a uniform increase or decrease of the predicted velocities, which could be detected as the small difference between the measured and the predicted relative plate velocities. Direct estimation of the correction suggests that the VLBI data fit best to the model when the NUVEL1 model is corrected by +3.4% (+/-1.2%), which differs significantly from the -4.5% deduced from the astronomical MPTS calibration. This was further confirmed by estimating the rotation rates for individual plate pairs.

  18. An improved synchronous reference frame current control strategy for a photovoltaic grid-connected inverter under unbalanced and nonlinear load conditions

    DEFF Research Database (Denmark)

    Naderipour, Amirreza; Asuhaimi Mohd Zin, Abdullah; Bin Habibuddin, Mohd Hafiz

    2017-01-01

    . It is challenging to suppress the harmonic content in the output current below a pre-set value in the GCI. It is also difficult to compensate for unbalanced loads even when the grid is under disruption due to total harmonic distortion (THD) and unbalanced loads. The primary advantage and objective of this method......In recent years, renewable energy sources have been considered the most encouraging resources for grid and off-grid power generation. This paper presents an improved current control strategy for a three-phase photovoltaic grid-connected inverter (GCI) under unbalanced and nonlinear load conditions...... to control the active and reactive power and harmonic current compensation, and it also corrects the system unbalance. The proposed control method features the synchronous reference frame (SRF) method. Simulation results are presented to demonstrate the effective performance of the proposed method....

  19. On the relation between zero-points of the dynamical (DE200) and catalogue (FK5) reference frames from observations of the Sun 1941 - 1982.

    Science.gov (United States)

    Duma, D. P.; Kozel, O. V.

    1998-04-01

    The authors discuss the relation between catalogue and dynamical zero-points from observations of the Sun using the geometrical and analytical approaches. The comparative analysis of equations used is carried out. Washington (1941 - 1977) and Greenwich (1942 - 1982) observations of the Sun have been reduced to the FK4 and FK5 systems. The angles of mutual orientation of axes of dynamical (DE200) and catalogue (FK5) reference frames have been estimated. The results based on the geometrical approach are characterized by better convergence and higher accuracy. The assumption is made that the effect of the non-precessional equinox motion may be a consequence of an imperfection of the technique of its study as well as of the incomplete theory of the Sun motion.

  20. Studying the relation between the zero-points of the dynamical (DE200) and catalog (FK5) reference frames from observations of the Sun 1941-1982.

    Science.gov (United States)

    Duma, D. P.; Kozel, O. V.

    The authors discuss the relation between the catalog and dynamical zero-points within the framework of the geometric and analytical approaches. Comparative analysis of the equations used is made. The study is based on the Washington (1941 - 1977) and Greenwich (1942 - 1982) observations of the Sun reduced to the FK4 and FK5 systems. The angles of mutual orientation of axes of the dynamical (DE200) and catalog (FK5) reference frames are estimated. The results obtained in the geometric approach agree better and are more accurate. The effect of the non-precessional motion of equinox is assumed to arise from imperfections in the technique and in the theory of the motion of the Sun.

  1. Hubble peers inside a celestial geode

    Science.gov (United States)

    2004-08-01

    celestial geode hi-res Size hi-res: 148 Kb Credits: ESA/NASA, Yäel Nazé (University of Liège, Belgium) and You-Hua Chu (University of Illinois, Urbana, USA) Hubble peers inside a celestial geode In this unusual image, the NASA/ESA Hubble Space Telescope captures a rare view of the celestial equivalent of a geode - a gas cavity carved by the stellar wind and intense ultraviolet radiation from a young hot star. Real geodes are handball-sized, hollow rocks that start out as bubbles in volcanic or sedimentary rock. Only when these inconspicuous round rocks are split in half by a geologist, do we get a chance to appreciate the inside of the rock cavity that is lined with crystals. In the case of Hubble's 35 light-year diameter ‘celestial geode’ the transparency of its bubble-like cavity of interstellar gas and dust reveals the treasures of its interior. Low resolution version (JPG format) 148 Kb High resolution version (TIFF format) 1929 Kb Acknowledgment: This image was created with the help of the ESA/ESO/NASA Photoshop FITS Liberator. Real geodes are handball-sized, hollow rocks that start out as bubbles in volcanic or sedimentary rock. Only when these inconspicuous round rocks are split in half by a geologist, do we get a chance to appreciate the inside of the rock cavity that is lined with crystals. In the case of Hubble's 35 light-year diameter ‘celestial geode’ the transparency of its bubble-like cavity of interstellar gas and dust reveals the treasures of its interior. The object, called N44F, is being inflated by a torrent of fast-moving particles (what astronomers call a 'stellar wind') from an exceptionally hot star (the bright star just below the centre of the bubble) once buried inside a cold dense cloud. Compared with our Sun (which is losing mass through the so-called 'solar wind'), the central star in N44F is ejecting more than a 100 million times more mass per second and the hurricane of particles moves much faster at 7 million km per hour

  2. Reliable measurement of 3D foot bone angles based on the frame-of-reference derived from a sole of the foot

    Science.gov (United States)

    Kim, Taeho; Lee, Dong Yeon; Park, Jinah

    2016-03-01

    Clinical management of foot pathology requires accurate and robust measurement of the anatomical angles. In order to measure a 3D angle, recent approaches have adopted a landmark-based local coordinate system to establish bone angles used in orthopedics. These measurement methods mainly assess the relative angle between bones using a representative axis derived from the morphological feature of the bone and therefore, the results can be affected by bone deformities. In this study, we propose a method of deriving a global frame-of-reference to acquire consistent direction of the foot by extracting the undersurface of the foot from the CT image data. The two lowest positions of the foot skin are identified from the surface to define the base plane, and the direction from the hallux to the fourth toe is defined together to construct the global coordinate system. We performed the experiment on 10 volumes of foot CT images of healthy subjects to verify that the proposed method provides reliable measurements. We measured 3D angles for talus-calcaneus and talus-navicular using facing articular surfaces of paired bones. The angle was reported in 3 projection angles based on both coordinate systems defined by proposed global frame-of-reference and by CT image planes (saggital, frontal, and transverse). The result shows that the quantified angle using the proposed method considerably reduced the standard deviation (SD) against the angle using the conventional projection planes, and it was also comparable with the measured angles obtained from local coordinate systems of the bones. Since our method is independent from any individual local shape of a bone, unlike the measurement method using the local coordinate system, it is suitable for inter-subject comparison studies.

  3. A new velocity field for Africa from combined GPS and DORIS space geodetic Solutions: Contribution to the definition of the African reference frame (AFREF)

    Science.gov (United States)

    Saria, E.; Calais, E.; Altamimi, Z.; Willis, P.; Farah, H.

    2013-04-01

    We analyzed 16 years of GPS and 17 years of Doppler orbitography and radiopositioning integrated by satellite (DORIS) data at continuously operating geodetic sites in Africa and surroundings to describe the present-day kinematics of the Nubian and Somalian plates and constrain relative motions across the East African Rift. The resulting velocity field describes horizontal and vertical motion at 133 GPS sites and 9 DORIS sites. Horizontal velocities at sites located on stable Nubia fit a single plate model with a weighted root mean square residual of 0.6 mm/yr (maximum residual 1 mm/yr), an upper bound for plate-wide motions and for regional-scale deformation in the seismically active southern Africa and Cameroon volcanic line. We confirm significant southward motion ( ˜ 1.5 mm/yr) in Morocco with respect to Nubia, consistent with earlier findings. We propose an updated angular velocity for the divergence between Nubia and Somalia, which provides the kinematic boundary conditions to rifting in East Africa. We update a plate motion model for the East African Rift and revise the counterclockwise rotation of the Victoria plate and clockwise rotation of the Rovuma plate with respect to Nubia. Vertical velocities range from - 2 to +2 mm/yr, close to their uncertainties, with no clear geographic pattern. This study provides the first continent-wide position/velocity solution for Africa, expressed in International Terrestrial Reference Frame (ITRF2008), a contribution to the upcoming African Reference Frame (AFREF). Except for a few regions, the African continent remains largely under-sampled by continuous space geodetic data. Efforts are needed to augment the geodetic infrastructure and openly share existing data sets so that the objectives of AFREF can be fully reached.

  4. Frames and semi-frames

    OpenAIRE

    Antoine, Jean-Pierre; Balazs, Peter

    2011-01-01

    Loosely speaking, a semi-frame is a generalized frame for which one of the frame bounds is absent. More precisely, given a total sequence in a Hilbert space, we speak of an upper (resp. lower) semi-frame if only the upper (resp. lower) frame bound is valid. Equivalently, for an upper semi-frame, the frame operator is bounded, but has an unbounded inverse, whereas a lower semi-frame has an unbounded frame operator, with bounded inverse. We study mostly upper semi-frames, bot...

  5. The North Celestial Pole Monitoring Project

    Science.gov (United States)

    Blake, R. M.; Castelaz, M.; Phillips, J.

    2005-05-01

    In the past ten years a renaissance has occurred in the study of transient phenomena using small, dedicated optical telescopes. This has largely been driven by the successful detection of planetary transits with small telescopes (Henry et al. 2000) and the successful recovery of optical afterglows of gamma ray bursts (e.g. Halpern et al. 1997). The telescopes involved are designed to slew at rapid rates accurately across the sky when a burst alert occurs, or to study a single patch of sky to detect transits. We have constructed a dedicated robotic instrument to monitor the region within 4 degrees of the north celestial pole continuously every clear night. Using a sequence of short and long exposures the telescope collects data to conduct searches for transient and variable objects and monitor the Cepheid variable Polaris. Previous authors (Kamper et al. 1984; Evans et al. 1998) have observed Polaris to nearly cease its pulsation, a unique behavior for a Cepheid variable. Monitoring Polaris with high secular coverage should help explain this behavior. We describe here the design of the observatory, its operation and control systems and give preliminary examples of the data products from this unique project.

  6. Celestial shadows eclipses, transits, and occultations

    CERN Document Server

    Westfall, John

    2015-01-01

    Much of what is known about the universe comes from the study of celestial shadows—eclipses, transits, and occultations.  The most dramatic are total eclipses of the Sun, which constitute one of the most dramatic and awe-inspiring events of nature.  Though once a source of consternation or dread, solar eclipses now lead thousands of amateur astronomers and eclipse-chasers to travel to remote points on the globe to savor their beauty and the adrenaline-rush of experiencing totality, and were long the only source of information about the hauntingly beautiful chromosphere and corona of the Sun.   Long before Columbus, the curved shadow of the Earth on the Moon during a lunar eclipse revealed that we inhabit a round world. The rare and wonderful transits of Venus, which occur as it passes between the Earth and the Sun, inspired eighteenth century expeditions to measure the distance from the Earth to the Sun, while the recent transits of 2004 and 2012 were the most widely observed ever--and still produced re...

  7. Protection of celestial environments and the law of outer space

    Science.gov (United States)

    Tennen, Leslie; Race, Margaret

    The law of outer space expressly addresses the matter of preservation and protection of natural celestial environments from harmful contamination and disruption by mankind in the explo-ration and use of outer space, including the moon and other celestial bodies. The Outer Space Treaty, however, does not prohibit all human impact to an extraterrestrial environment, but rather permits a wide range of activities that could have significant environmental ramifications. This legal regime may be in conflict with the interests of preserving celestial environments for scientific research, especially when considered in relation to activities conducted for commercial purposes. Nevertheless, the Moon Agreement provides a mechanism by which special protective measures can be implemented to protect particular areas of the moon and other celestial bodies for scientific investigation. This paper examines the current status of the law of outer space vis-a-vis the protection and preservation of natural celestial environments. Particular emphasis is placed on the policies on which the legal obligations are based, together with consideration of the non-appropriation principle, and the commercial use of lunar and other celestial resources and areas. In addition, the concepts of international scientific preserves, special regions, keep out zones, and planetary parks are compared and evaluated as potential means to limit the disturbance to celestial environments caused by the activities of mankind.

  8. Frame of Reference: Special Collections

    Science.gov (United States)

    Goetsch, Lori A.

    2010-01-01

    Rare, distinctive, unique--academic libraries are exploring new ways to describe and define what they've traditionally called special collections: incunabula, manuscripts, rare books, cultural artifacts and more. These valuable, historically important, and often one-of-a-kind artifacts can be a treasure trove for scholars and students. Technology…

  9. Daytime Celestial Navigation for the Novice

    Science.gov (United States)

    Sadler, Philip M.; Night, Christopher

    2010-03-01

    What kinds of astronomical lab activities can high school and college astronomy students carry out easily in daytime? The most impressive is the determination of latitude and longitude from observations of the Sun. The ``shooting of a noon sight'' and its ``reduction to a position'' grew to become a daily practice at the start of the 19th century1 following the perfection of the marine chronometer by John Harrison and its mass production.2 This technique is still practiced by navigators in this age of GPS. Indeed, the U.S. Coast Guard exams for ocean-going licenses include celestial navigation.3 These techniques continue to be used by the military and by private sailors as a backup to all-too-fallible and jammable electronic navigation systems. A sextant, a nautical almanac,4 special sight reduction tables,5 and involved calculations are needed to determine position to the nearest mile using the Sun, Moon, stars, or planets. Yet, finding latitude and longitude to better than 30 miles from measurements of the Sun's altitude is easily within the capability of those taking astronomy or physics for the first time by applying certain basic principles. Moreover, it shows a practical application of astronomy in use the world over. The streamlined method described here takes advantage of the similar level of accuracy of its three components: 1.Observations using a homemade quadrant6 (instead of a sextant), 2. Student-made graphs of the altitude of the Sun over a day7 (replacing lengthy calculation using sight reduction tables), and 3. An averaged 20-year analemma used to find the Sun's navigational coordinates8,9 (rather than the 300+ page Nautical Almanac updated yearly).

  10. Kinematics of Mid-Ocean Ridge Relative Motions in the Indo-Atlantic Frame of Reference: Passive and Active Spreading Ridges

    Science.gov (United States)

    Rowan, C. J.; Rowley, D. B.; Forte, A. M.

    2011-12-01

    A kinematic analysis of the motions of mid-ocean ridges is presented in the Indo-Atlantic hotspot frame of reference. Relative motions of all major divergent plate boundaries are computed, including an assessment of uncertainties in their motions, back to 83 Ma (C34ny). As is expected from the general assumption that ridges are passive components of the plate boundary and mantle convective system, most ridges migrate across the underlying mantle along simple paths, largely perpendicular to the trend of the ridge. In the Indo-Atlantic reference frame, the Nansen-Gakkel ridge has migrated away from Europe by ~800 km along a NE trajectory. The Mid Atlantic Ridge (MAR) just north of the Azores triple junction (TJ) has moved away from Europe by ~1800km towards the WNW. South of the Azores TJ the MAR has moved away from Africa by ~1600 km towards the W. The slow to ultraslow spreading Southwest Indian Ridge has migrated slightly away from Antarctica, with a considerable fraction of the motion approximately parallel to the ridge trend. The Carlsberg Ridge has moved ~3400 km away from Africa towards the NNE in the past 65 Ma, while the Mid-Indian Ridge has migrated to the NNE away from Africa by ~3950 km over 83 Ma. The Southeast Indian Ridge, west of the 90°E ridge (Capricorn-Australia-East Antarctica TJ), has migrated ~3950 km to the NE away from Antarctica. Farther east, divergence between Australia and Antarctica has resulted in ~1800 km of northward motion of the ridge away from Antarctica. The Southwest Pacific Ridge, between the Pacific and West Antarctic plates has migrated ~1500 km to the NW away from west Antarctica. These motions are entirely consistent with intuition, given that Africa and Antarctica are largely surrounded by spreading systems. In contrast to the rest of the global ridge system, despite its high spreading rate the East Pacific Ridge has undergone essentially no (ridge perpendicular (E-W) migration in the past 80 Ma, and neglible ridge parallel

  11. Celestial delights the best astronomical events through 2020

    CERN Document Server

    Reddy, Francis

    2012-01-01

    Celestial Delights is the essential 'TV Guide' for the sky. Through extensive graphics integrated with an eight-year-long calendar of sky events, it provides a look at "don't miss" sky events, mostly for naked-eye and binocular observing. It is organized by ease of observation – lunar phases and the brighter planets come first, with solar eclipses, the aurora, and comets coming later. This third edition also includes a hefty dose of sky lore, astronomical history, and clear overviews of current science. It provides a handy reference to upcoming naked-eye events, with information broken out in clear and simple diagrams and tables that are cross-referenced against a detailed almanac for each year covered. This book puts a variety of information all in one place, presents it in a friendly way that does not require prior in-depth astronomical knowledge, and provides the context and historical background for understanding events that astronomy software or web sites lack.

  12. Industrial Scale Production of Celestial Body Simulants, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The technical objectives of this program are to develop a cost-effective process to deliver Celestial body simulants for the foreseeable future. Specifically, the...

  13. Coherence between geophysical excitations and celestial pole offsets

    Czech Academy of Sciences Publication Activity Database

    Ron, Cyril; Vondrák, Jan

    2011-01-01

    Roč. 8, č. 3 (2011), s. 243-247 ISSN 1214-9705. [Czech-Polish Workshop on Recent Geodynamics of the Sudeten and Adjacent Areas. Třešť, 04.11.2010-06.11. 2010] R&D Projects: GA ČR GA205/08/0908 Institutional research plan: CEZ:AV0Z10030501 Keywords : geophysical excitations * celestial pole offsets * coherence Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.530, year: 2011

  14. Interactive navigation-guided ophthalmic plastic surgery: assessment of optical versus electromagnetic modes and role of dynamic reference frame location using navigation-enabled human skulls.

    Science.gov (United States)

    Ali, Mohammad Javed; Naik, Milind N; Girish, Chetan Mallikarjuniah; Ali, Mohammad Hasnat; Kaliki, Swathi; Dave, Tarjani Vivek; Dendukuri, Gautam

    2016-01-01

    The aim of this study was to assess the anatomical accuracy of navigation technology in localizing defined anatomic landmarks within the orbit with respect to type of technology (optical versus electromagnetic systems) and position of the dynamic reference marker on the skull (vertex, temporal, parietal, and mastoid) using in vitro navigation-enabled human skulls. The role of this model as a possible learning tool for anatomicoradiological correlations was also assessed. Computed tomography (CT) scans were performed on three cadaveric human skulls using the standard image-guidance acquisition protocols. Thirty-five anatomical landmarks were identified for stereotactic navigation using the image-guided StealthStation S7™ in both electromagnetic and optical modes. Three outcome measures studied were accuracy of anatomical localization and its repeatability, comparisons between the electromagnetic and optical modes in assessing radiological accuracy, and the efficacy of dynamic reference frame (DRF) at different locations on the skull. The geometric localization of all the identified anatomical landmarks could be achieved accurately. The Cohen's kappa agreements between the surgeons were found to be perfect (kappa =0.941) at all predetermined points. There was no difference in anatomical localization between the optical and electromagnetic modes ( P ≤0.001). Precision for radiological identification did not differ with various positions of the DRF. Skulls with intact anatomical details and careful CT image acquisitions were found to be stereotactically useful. Accuracy of anatomic localization within the orbit with navigation technology is equal with optical and electromagnetic system. The location of DRF does not affect the accuracy. Navigation-enabled skull models can be potentially useful as teaching tools for achieving the accurate radiological orientation of orbital and periorbital structures.

  15. An improved synchronous reference frame current control strategy for a photovoltaic grid-connected inverter under unbalanced and nonlinear load conditions

    Science.gov (United States)

    Naderipour, Amirreza; Asuhaimi Mohd Zin, Abdullah; Bin Habibuddin, Mohd Hafiz; Miveh, Mohammad Reza; Guerrero, Josep M.

    2017-01-01

    In recent years, renewable energy sources have been considered the most encouraging resources for grid and off-grid power generation. This paper presents an improved current control strategy for a three-phase photovoltaic grid-connected inverter (GCI) under unbalanced and nonlinear load conditions. It is challenging to suppress the harmonic content in the output current below a pre-set value in the GCI. It is also difficult to compensate for unbalanced loads even when the grid is under disruption due to total harmonic distortion (THD) and unbalanced loads. The primary advantage and objective of this method is to effectively compensate for the harmonic current content of the grid current and microgrid without the use of any compensation devices, such as active and passive filters. This method leads to a very low THD in both the GCI currents and the current exchanged with the grid. The control approach is designed to control the active and reactive power and harmonic current compensation, and it also corrects the system unbalance. The proposed control method features the synchronous reference frame (SRF) method. Simulation results are presented to demonstrate the effective performance of the proposed method. PMID:28192436

  16. Mixed quantum/classical theory of rotationally and vibrationally inelastic scattering in space-fixed and body-fixed reference frames.

    Science.gov (United States)

    Semenov, Alexander; Babikov, Dmitri

    2013-11-07

    We formulated the mixed quantum/classical theory for rotationally and vibrationally inelastic scattering process in the diatomic molecule + atom system. Two versions of theory are presented, first in the space-fixed and second in the body-fixed reference frame. First version is easy to derive and the resultant equations of motion are transparent, but the state-to-state transition matrix is complex-valued and dense. Such calculations may be computationally demanding for heavier molecules and/or higher temperatures, when the number of accessible channels becomes large. In contrast, the second version of theory requires some tedious derivations and the final equations of motion are rather complicated (not particularly intuitive). However, the state-to-state transitions are driven by real-valued sparse matrixes of much smaller size. Thus, this formulation is the method of choice from the computational point of view, while the space-fixed formulation can serve as a test of the body-fixed equations of motion, and the code. Rigorous numerical tests were carried out for a model system to ensure that all equations, matrixes, and computer codes in both formulations are correct.

  17. An improved synchronous reference frame current control strategy for a photovoltaic grid-connected inverter under unbalanced and nonlinear load conditions.

    Science.gov (United States)

    Naderipour, Amirreza; Asuhaimi Mohd Zin, Abdullah; Bin Habibuddin, Mohd Hafiz; Miveh, Mohammad Reza; Guerrero, Josep M

    2017-01-01

    In recent years, renewable energy sources have been considered the most encouraging resources for grid and off-grid power generation. This paper presents an improved current control strategy for a three-phase photovoltaic grid-connected inverter (GCI) under unbalanced and nonlinear load conditions. It is challenging to suppress the harmonic content in the output current below a pre-set value in the GCI. It is also difficult to compensate for unbalanced loads even when the grid is under disruption due to total harmonic distortion (THD) and unbalanced loads. The primary advantage and objective of this method is to effectively compensate for the harmonic current content of the grid current and microgrid without the use of any compensation devices, such as active and passive filters. This method leads to a very low THD in both the GCI currents and the current exchanged with the grid. The control approach is designed to control the active and reactive power and harmonic current compensation, and it also corrects the system unbalance. The proposed control method features the synchronous reference frame (SRF) method. Simulation results are presented to demonstrate the effective performance of the proposed method.

  18. Frames and semi-frames

    Energy Technology Data Exchange (ETDEWEB)

    Antoine, Jean-Pierre [Institut de Recherche en Mathematique et Physique, Universite Catholique de Louvain, B-1348 Louvain-la Neuve (Belgium); Balazs, Peter, E-mail: jean-pierre.antoine@uclouvain.be, E-mail: peter.balazs@oeaw.ac.at [Acoustics Research Institute, Austrian Academy of Sciences, Wohllebengasse 12-14, A-1040 Vienna (Austria)

    2011-05-20

    Loosely speaking, a semi-frame is a generalized frame for which one of the frame bounds is absent. More precisely, given a total sequence in a Hilbert space, we speak of an upper (resp. lower) semi-frame if only the upper (resp. lower) frame bound is valid. Equivalently, for an upper semi-frame, the frame operator is bounded, but has an unbounded inverse, whereas a lower semi-frame has an unbounded frame operator, with a bounded inverse. We study mostly upper semi-frames, both in the continuous and discrete case, and give some remarks for the dual situation. In particular, we show that reconstruction is still possible in certain cases.

  19. Effects of achievement differences for internal/external frame of reference model investigations: A test of robustness of findings over diverse student samples.

    Science.gov (United States)

    Schmidt, Isabelle; Brunner, Martin; Preckel, Franzis

    2017-11-12

    Achievement in math and achievement in verbal school subjects are more strongly correlated than the respective academic self-concepts. The internal/external frame of reference model (I/E model; Marsh, 1986, Am. Educ. Res. J., 23, 129) explains this finding by social and dimensional comparison processes. We investigated a key assumption of the model that dimensional comparisons mainly depend on the difference in achievement between subjects. We compared correlations between subject-specific self-concepts of groups of elementary and secondary school students with or without achievement differences in the respective subjects. The main goals were (1) to show that effects of dimensional comparisons depend to a large degree on the existence of achievement differences between subjects, (2) to demonstrate the generalizability of findings over different grade levels and self-concept scales, and (3) to test a rarely used correlation comparison approach (CCA) for the investigation of I/E model assumptions. We analysed eight German elementary and secondary school student samples (grades 3-8) from three independent studies (Ns 326-878). Correlations between math and German self-concepts of students with identical grades in the respective subjects were compared with the correlation of self-concepts of students having different grades using Fisher's Z test for independent samples. In all samples, correlations between math self-concept and German self-concept were higher for students having identical grades than for students having different grades. Differences in median correlations had small effect sizes for elementary school students and moderate effect sizes for secondary school students. Findings generalized over grades and indicated a developmental aspect in self-concept formation. The CCA complements investigations within I/E-research. © 2017 The British Psychological Society.

  20. Frontiers in Relativistic Celestial Mechanics, Vol. 1. Theory

    Science.gov (United States)

    Kopeikin, Sergei

    2014-10-01

    Relativistic celestial mechanics - investigating the motion celestial bodies under the influence of general relativity - is a major tool of modern experimental gravitational physics. With a wide range of prominent authors from the field, this two-volume series consists of reviews on a multitude of advanced topics in the area of relativistic celestial mechanics - starting from more classical topics such as the regime of asymptotically-flat spacetime, light propagation and celestial ephemerides, but also including its role in cosmology and alternative theories of gravity as well as modern experiments in this area. This first volume of a two-volume series is concerned with theoretical foundations such as post-Newtonian solutions to the two-body problem, light propagation through time-dependent gravitational fields, as well as cosmological effects on the movement of bodies in the solar systems. On the occasion of his 80-th birthday, these two volumes honor V. A. Brumberg - one of the pioneers in modern relativistic celestial mechanics. Contributions include: M. Soffel: On the DSX-framework T. Damour: The general relativistic two body problem G. Schaefer: Hamiltonian dynamics of spinning compact binaries through high post-Newtonian approximations A. Petrov and S. Kopeikin: Post-Newtonian approximations in cosmology T. Futamase: On the backreaction problem in cosmology Y. Xie and S. Kopeikin: Covariant theory of the post-Newtonian equations of motion of extended bodies S. Kopeikin and P. Korobkov: General relativistic theory of light propagation in multipolar gravitational fields

  1. Changing climate, changing frames

    International Nuclear Information System (INIS)

    Vink, Martinus J.; Boezeman, Daan; Dewulf, Art; Termeer, Catrien J.A.M.

    2013-01-01

    Highlights: ► We show development of flood policy frames in context of climate change attention. ► Rising attention on climate change influences traditional flood policy framing. ► The new framing employs global-scale scientific climate change knowledge. ► With declining attention, framing disregards climate change, using local knowledge. ► We conclude that frames function as sensemaking devices selectively using knowledge. -- Abstract: Water management and particularly flood defence have a long history of collective action in low-lying countries like the Netherlands. The uncertain but potentially severe impacts of the recent climate change issue (e.g. sea level rise, extreme river discharges, salinisation) amplify the wicked and controversial character of flood safety policy issues. Policy proposals in this area generally involve drastic infrastructural works and long-term investments. They face the difficult challenge of framing problems and solutions in a publicly acceptable manner in ever changing circumstances. In this paper, we analyse and compare (1) how three key policy proposals publicly frame the flood safety issue, (2) the knowledge referred to in the framing and (3) how these frames are rhetorically connected or disconnected as statements in a long-term conversation. We find that (1) framings of policy proposals differ in the way they depict the importance of climate change, the relevant timeframe and the appropriate governance mode; (2) knowledge is selectively mobilised to underpin the different frames and (3) the frames about these proposals position themselves against the background of the previous proposals through rhetorical connections and disconnections. Finally, we discuss how this analysis hints at the importance of processes of powering and puzzling that lead to particular framings towards the public at different historical junctures

  2. Celestial Navigation, with a Moral Compass.

    Science.gov (United States)

    Donovan, Aine

    1999-01-01

    Kantian reasoning fails to address the needs of a mixed-gender peace-keeping force. A philosophy professor at the U.S. Naval Academy proposes a normative-ethics instructional model based on acceptance of duty and obedience (justice) and cultivation of reflective concern for individual choice and responsibility (caring). (24 references) (MLH)

  3. Social scaling of extrapersonal space: target objects are judged as closer when the reference frame is a human agent with available movement potentialities.

    Science.gov (United States)

    Fini, C; Brass, M; Committeri, G

    2015-01-01

    Space perception depends on our motion potentialities and our intended actions are affected by space perception. Research on peripersonal space (the space in reaching distance) shows that we perceive an object as being closer when we (Witt, Proffitt, & Epstein, 2005; Witt & Proffitt, 2008) or another actor (Costantini, Ambrosini, Sinigaglia, & Gallese, 2011; Bloesch, Davoli, Roth, Brockmole, & Abrams, 2012) can interact with it. Similarly, an object only triggers specific movements when it is placed in our peripersonal space (Costantini, Ambrosini, Tieri, Sinigaglia, & Committeri, 2010) or in the other's peripersonal space (Costantini, Committeri, & Sinigaglia, 2011; Cardellicchio, Sinigaglia, & Costantini, 2013). Moreover, also the extrapersonal space (the space outside reaching distance) seems to be perceived in relation to our movement capabilities: the more effort it takes to cover a distance, the greater we perceive the distance to be (Proffitt, Stefanucci, Banton, & Epstein, 2003; Sugovic & Witt, 2013). However, not much is known about the influence of the other's movement potentialities on our extrapersonal space perception. Three experiments were carried out investigating the categorization of distance in extrapersonal space using human or non-human allocentric reference frames (RF). Subjects were asked to judge the distance ("Near" or "Far") of a target object (a beach umbrella) placed at progressively increasing or decreasing distances until a change from near to far or vice versa was reported. In the first experiment we found a significant "Near space extension" when the allocentric RF was a human virtual agent instead of a static, inanimate object. In the second experiment we tested whether the "Near space extension" depended on the anatomical structure of the RF or its movement potentialities by adding a wooden dummy. The "Near space extension" was only observed for the human agent but not for the dummy. Finally, to rule out the possibility that the

  4. Azimuth method for ship position in celestial navigation

    Directory of Open Access Journals (Sweden)

    Van-Suong Nguyen

    2017-06-01

    Full Text Available The methods of celestial navigation to fix the ship position in line with the stars are only applied in the twilight time interval when both the celestial bodies and the horizon apppear simultaneously. This means that these methods cannot be used during the night even if the stars are visible. This paper proposes a novel approach which uses the azimuth of the celestial body in order to establish the great circle equation relating the observed body to the ship position when the celestial bodies appear. In addition, the proposed method does not demand the horizon and sextant equipment as with the previous methods. The key advantage which differentiates this method from previous ones is its ability to determine the ship position during the night when the horizon is invisible. Firstly, the vector calculus is applied to find the mathematical equation for the ship position through analyzing the relationship between the ship position and the great-circle azimuth of the observed body. Secondly, the equation system for the ship position is expanded into a standard system in which the input for the proposed mathematical system are the great-circle azimuth and the coordinates of the observed body. Finally, the numerical technique is also proposed to solve the nonlinear system for the ship position. To verify the validation of this proposed method, a numerical experiment is carried out and the results show that it can be applied well in practice.

  5. Influence of celestial parameters on Mercury's perihelion shift

    Czech Academy of Sciences Publication Activity Database

    Křížek, Michal

    2017-01-01

    Roč. 27, June (2017), s. 41-56 ISSN 1313-2709 Institutional support: RVO:67985840 Keywords : solar system * ephemeris * line of apsides Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) http://www.astro.bas.bg/AIJ/issues/n27/MKrizek.pdf

  6. Influence of celestial parameters on Mercury's perihelion shift

    Czech Academy of Sciences Publication Activity Database

    Křížek, Michal

    2017-01-01

    Roč. 27, June (2017), s. 41-56 ISSN 1313-2709 Institutional support: RVO:67985840 Keywords : solar system * ephemeris * line of apsides Subject RIV: BN - Astronomy, Celestial Mechanics , Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) http://www.astro.bas.bg/AIJ/issues/n27/MKrizek.pdf

  7. Framing politics

    NARCIS (Netherlands)

    Lecheler, S.K.

    2010-01-01

    This dissertation supplies a number of research findings that add to a theory of news framing effects, and also to the understanding of the role media effects play in political communication. We show that researchers must think more about what actually constitutes a framing effect, and that a

  8. On Framing

    DEFF Research Database (Denmark)

    Peder Pedersen, Claus

    2018-01-01

    On framing as artistic and conceptual tool in the works of Claudia Carbone. Contribution to exhibition at the Aarhus School of Architecture.......On framing as artistic and conceptual tool in the works of Claudia Carbone. Contribution to exhibition at the Aarhus School of Architecture....

  9. On Safety Management. A Frame of Reference for Studies of Safety Management with Examples From Non-Nuclear Contexts of Relevance for Nuclear Safety

    International Nuclear Information System (INIS)

    Svensson, Ola; Salo, Ilkka; Allwin, Pernilla

    2004-11-01

    operations, and safety management for each organization respectively. The analyses are described and summarized in detail in each chapter. To summarize some general themes from the analyzes the following are important to mention: -A distinct division of responsibilities for safety work between organizational units. -A clear communication about the organization's safety policy and how each member of the organization is a part of the policy. -Channels for information and information feedback are clearly represented in the system structure. -Availability to incident reporting systems and the responsibility of each member of the organization to report incidents. -The importance to differentiate between established structures for information management and established structures for information content. -To make clear the range and meaning of power and authority. -Identification of the organizations' competence and integrity in relation to safety management. -The importance of identifying threats to safety, not only for company activities and operations but also for authority activities and operations. In the next phase of the ongoing project, we wish to gain more insight in the companies' perspectives of safety management. The system theoretical framework outlined in this report will be used as a frame of reference for the analyses. We believe that the results from this and future studies in the project will give opportunities to take further steps towards improving safety in the nuclear power operations, both from a company and from a regulator perspective

  10. Framing Fragmentation

    DEFF Research Database (Denmark)

    Bundgaard, Charlotte

    2009-01-01

    to create architectural meaning and give character to an architecture of fragmentation. Layers are both seen as conceptual as well as material frames which define certain strong properties or meanings in the architectural work. Defining layers is a way of separating and organizing; it both defines...

  11. Review on the Celestial Sphere Positioning of FITS Format Image Based on WCS and Research on General Visualization

    Science.gov (United States)

    Song, W. M.; Fan, D. W.; Su, L. Y.; Cui, C. Z.

    2017-11-01

    Calculating the coordinate parameters recorded in the form of key/value pairs in FITS (Flexible Image Transport System) header is the key to determine FITS images' position in the celestial system. As a result, it has great significance in researching the general process of calculating the coordinate parameters. By combining CCD related parameters of astronomical telescope (such as field, focal length, and celestial coordinates in optical axis, etc.), astronomical images recognition algorithm, and WCS (World Coordinate System) theory, the parameters can be calculated effectively. CCD parameters determine the scope of star catalogue, so that they can be used to build a reference star catalogue by the corresponding celestial region of astronomical images; Star pattern recognition completes the matching between the astronomical image and reference star catalogue, and obtains a table with a certain number of stars between CCD plane coordinates and their celestial coordinates for comparison; According to different projection of the sphere to the plane, WCS can build different transfer functions between these two coordinates, and the astronomical position of image pixels can be determined by the table's data we have worked before. FITS images are used to carry out scientific data transmission and analyze as a kind of mainstream data format, but only to be viewed, edited, and analyzed in the professional astronomy software. It decides the limitation of popular science education in astronomy. The realization of a general image visualization method is significant. FITS is converted to PNG or JPEG images firstly. The coordinate parameters in the FITS header are converted to metadata in the form of AVM (Astronomy Visualization Metadata), and then the metadata is added to the PNG or JPEG header. This method can meet amateur astronomers' general needs of viewing and analyzing astronomical images in the non-astronomical software platform. The overall design flow is realized

  12. 5th Austrian Hungarian workshop on celestial mechanics

    Science.gov (United States)

    Süli, Áron

    2011-06-01

    The 5th Hungarian-Austrian Workshop on Celestial Mechanics took place from 9th until the 10th of April 2010 in Vienna, Austria. The workshop was held in the Institute for Astronomy of Vienna University. From the Eötvös University and from the host institute experts and PhD students gathered together to discuss the challenges and new results of the actual problems of celestial mechanics. The workshop was held in the meeting room at the Sternwarte of the Vienna University located in a magnificent park in the heart of Vienna. Following the themes of the four previous events the focus for this workshop ranged from the Trojan problem, dynamics in binary star systems and exoplanetray systems. We were pleased to acknowledge the support of the host university. The talks were characterized by a large spectrum, which is typical of the workshops on celestial mechanics. Several talks discussed different aspects of the trojan problem, such as the three Trojan Problem, dynamics of trojan-like planets in binary stars, the frequencies of their motion around the triangular lagrangian points, etc. Several speakers focused on the formation of planetary systems and on the field of exoplanetary systems, like exoplanetary systems in higher order mean motion resonances, formation of planets in binary systems, stability of exomoons etc. Some of the presentation used sophisticated mathematical tools in order to understand mean motion resonances, the Sitnikov problem applying the KAM and the Nekhoroshev theorem. The theme of a number of talks was the motion of Solar System bodies: dynamics of the newly discovered moons of Pluto and of near-Earth asteroids. General problems were also addressed, among others chaos in Hamiltonian systems, adaptive Lie-integration method and iterative solution approximation to the generalised Sitnikov problem.

  13. Framing Feminism

    OpenAIRE

    Mendes, Kaitlynn

    2011-01-01

    This article analyses the framing in four British and American newspapers of the second wave feminist movement during its most politically active period (1968–1982). Using content and critical discourse analysis of 555 news articles, the article investigates how movement members were represented, what problems and solutions to women’s oppression/inequality were posed and whose voices were used. This paper identifies: opposition to the movement, support for the movement, conflict and movement ...

  14. Kepler-16 Circumbinary System Validates Quantum Celestial Mechanics

    Directory of Open Access Journals (Sweden)

    Potter F.

    2012-01-01

    Full Text Available We report the application of quantum celestial mechanics (QCM to the Kepler-16 cir- cumbinary system which has a single planet orbiting binary stars with the important system parameters known to within one percent. Other gravitationally bound systems such as the Solar System of planets and the Jovian satellite systems have large uncertain- ties in their total angular momentum. Therefore, Kepler-16 allows us for the first time to determine whether the QCM predicted angular momentum per mass quantization is valid.

  15. Mixed quantum/classical theory for inelastic scattering of asymmetric-top-rotor + atom in the body-fixed reference frame and application to the H₂O + He system.

    Science.gov (United States)

    Semenov, Alexander; Dubernet, Marie-Lise; Babikov, Dmitri

    2014-09-21

    The mixed quantum/classical theory (MQCT) for inelastic molecule-atom scattering developed recently [A. Semenov and D. Babikov, J. Chem. Phys. 139, 174108 (2013)] is extended to treat a general case of an asymmetric-top-rotor molecule in the body-fixed reference frame. This complements a similar theory formulated in the space-fixed reference-frame [M. Ivanov, M.-L. Dubernet, and D. Babikov, J. Chem. Phys. 140, 134301 (2014)]. Here, the goal was to develop an approximate computationally affordable treatment of the rotationally inelastic scattering and apply it to H2O + He. We found that MQCT is somewhat less accurate at lower scattering energies. For example, below E = 1000 cm(-1) the typical errors in the values of inelastic scattering cross sections are on the order of 10%. However, at higher scattering energies MQCT method appears to be rather accurate. Thus, at scattering energies above 2000 cm(-1) the errors are consistently in the range of 1%-2%, which is basically our convergence criterion with respect to the number of trajectories. At these conditions our MQCT method remains computationally affordable. We found that computational cost of the fully-coupled MQCT calculations scales as n(2), where n is the number of channels. This is more favorable than the full-quantum inelastic scattering calculations that scale as n(3). Our conclusion is that for complex systems (heavy collision partners with many internal states) and at higher scattering energies MQCT may offer significant computational advantages.

  16. General-relativistic celestial mechanics. II. Translational equations of motion

    International Nuclear Information System (INIS)

    Damour, T.; Soffel, M.; Xu, C.

    1992-01-01

    The translational laws of motion for gravitationally interacting systems of N arbitrarily composed and shaped, weakly self-gravitating, rotating, deformable bodies are obtained at the first post-Newtonian approximation of general relativity. The derivation uses our recently introduced multi-reference-system method and obtains the translational laws of motion by writing that, in the local center-of-mass frame of each body, relativistic inertial effects combine with post-Newtonian self- and externally generated gravitational forces to produce a global equilibrium (relativistic generalization of d'Alembert's principle). Within the first post-Newtonian approximation [i.e., neglecting terms of order (v/c) 4 in the equations of motion], our work is the first to obtain complete and explicit results, in the form of infinite series, for the laws of motion of arbitrarily composed and shaped bodies. We first obtain the laws of motion of each body as an infinite series exhibiting the coupling of all the (Blanchet-Damour) post-Newtonian multipole moments of this body to the post-Newtonian tidal moments (recently defined by us) felt by this body. We then give the explicit expression of these tidal moments in terms of post-Newtonian multipole moments of the other bodies

  17. On the foundations of general relativistic celestial mechanics

    Science.gov (United States)

    Battista, Emmanuele; Esposito, Giampiero; Dell'Agnello, Simone

    2017-09-01

    Towards the end of nineteenth century, Celestial Mechanics provided the most powerful tools to test Newtonian gravity in the solar system and also led to the discovery of chaos in modern science. Nowadays, in light of general relativity, Celestial Mechanics leads to a new perspective on the motion of satellites and planets. The reader is here introduced to the modern formulation of the problem of motion, following what the leaders in the field have been teaching since the nineties, in particular, the use of a global chart for the overall dynamics of N bodies and N local charts describing the internal dynamics of each body. The next logical step studies in detail how to split the N-body problem into two sub-problems concerning the internal and external dynamics, how to achieve the effacement properties that would allow a decoupling of the two sub-problems, how to define external-potential-effacing coordinates and how to generalize the Newtonian multipole and tidal moments. The review paper ends with an assessment of the nonlocal equations of motion obtained within such a framework, a description of the modifications induced by general relativity on the theoretical analysis of the Newtonian three-body problem, and a mention of the potentialities of the analysis of solar-system metric data carried out with the Planetary Ephemeris Program.

  18. The Power of Stars How Celestial Observations Have Shaped Civilization

    CERN Document Server

    Penprase, Bryan E

    2011-01-01

    What are some of the connections that bind us to the stars? How have these connections been established? And how have people all around the world and throughout time reacted to the night sky, the sun and moon, in their poetry, mythology, rituals, and temples? This book explores the influence of the sky on both ancient and modern civilization, by providing a clear overview of the many ways in which humans have used the stars as an ordering principle in their cultures, and which today still inspire us intellectually, emotionally, and spiritually. The book explores constellation lore from around the world, celestial alignments of monuments and temples, both from ancient and modern civilizations, and the role the sky has played in the cultures of the Greek, Egyptian, Babylonian, Native American, Chinese, Mayan, Aztec, and Inca. Models of the universe from each of these cultures are described clearly, and each culture’s explanation of the stars, planets, and other celestial objects are described. The roots of as...

  19. The Mediterranean Plio-Pleistocene: A reference frame for astronomically paced low and high latitude climate changes (Jean Baptiste Lamarck Medal Lecture)

    Science.gov (United States)

    Lourens, Lucas

    2016-04-01

    The astronomical theory of climate has revolutionized our understanding of past climate change and the development of highly accurate geologic time scales for the entire Cenozoic. Most of this understanding has started with the construction of high-resolution stable oxygen isotope (18O) records from planktonic and benthic foraminifera of open ocean deep marine sediments explored by the international drilling operations of DSDP, ODP and IODP. These efforts culminated into global ocean isotopic stacked records, which give a clear picture of the evolution of the climate state through time. Fundamental for these reconstructions are the assumptions made between the astronomical forcing and the tuned time series and the accuracy of the astronomical solution. In the past decades, an astronomically calibrated time scale for the Pliocene and Pleistocene of the Mediterranean has been developed, which has become the reference for the standard Geologic Time Scale. Characteristic of the studied marine sediments are the cyclic lithological alternations, reflecting the interference between obliquity and precession-paced low latitude climate variability. These interference patterns allowed to evaluate the accuracy of astronomical solutions and to constrain the dynamical ellipticity of the Earth and tidal dissipation by the Sun and the Moon, which in turn provided the backbone for the widely applied LR04 open ocean benthic isotope stack of the past 5 Myr. So far, the assumed time lags between orbital forcing and the global climate response as reflected in LR04 have not been tested, while these assumptions hark back to SPECMAP, using simple ice sheet models and a limited number of radiometric dates. In addition, LR04 adopted a shorter response time for the smaller ice caps during the Pliocene. Here I present the first benthic 18O record of the Mediterranean reference scale, which strikingly mirrors the LR04. I will use this record to discuss the assumed phase relations and its

  20. Framing Suicide - Investigating the News Media and Public's Use of the Problematic Suicide Referents Freitod and Selbstmord in German-Speaking Countries.

    Science.gov (United States)

    Arendt, Florian

    2018-01-01

    In German-speaking countries, suicide experts recommend not using the suicide referents Freitod and Selbstmord, as their associative meanings relate to problematic concepts such as free will and crime. To investigate which terms - the neutral and recommended Suizid or Freitod and Selbstmord - have dominated news coverage and to reveal what terms the public actually used. A retrospective database study was undertaken on data from the period 2004-2016. First, we investigated how frequently the terms were used in news coverage via an automated content analysis. Second, we investigated how often individuals used the terms for information-seeking via Google's search engine, since it can be used as an indicator of the popularity of a given term within a given period. Analyses revealed that Selbstmord was the most frequently used term in the news and by the public. Importantly, the use of Suizid increased in both datasets, nearly approaching the Selbstmord level in the later years. Although on a low level, the highly problematic term Freitod has also been in regular use. Media interventions should continue trying to increase journalists' awareness so that they use appropriate terms when reporting on suicide.

  1. Marco de referencia conceptual para la construcción de ambientes virtuales de enseñanza y aprendizaje / Frame of Conceptual Reference to the Construction of Virtual Environments of Education And Of Learning

    Directory of Open Access Journals (Sweden)

    Maria Elena Giraldo Ramirez

    2007-01-01

    Full Text Available Este texto pretende dar cuenta del marco de referencia conceptual que soporta los trabajos investigativos del Grupo EAV en torno al tema de la educación virtual y de las tecnologías de información y comunicación. Este marco plantea dos enfoques, el primero, un enfoque antropológico, para acercarse a la comprensión de la relación Tecnología-Comunicación-Educación que reconocemos como la tríada; y el segundo, un enfoque comunicacional que despliega la tríada contemporánea desde dos principios conceptuales: la mediación y la interacción.This paper tries to realize of the frame of conceptual reference that supports the works of research of the Group EAV around the topic of the virtual education and of the technologies of information and communication. This frame raises two approaches, the first one, an anthropologic approach, to approach the comprehension of the relation Technology, Communication and Education that we recognize as the triad; and the second one, a communication approach that develops the contemporary triad from two conceptual principles: the mediation and the interaction.

  2. Celestial Navigation Fix Based on Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Tsou Ming-Cheng

    2015-09-01

    Full Text Available A technique for solving celestial fix problems is proposed in this study. This method is based on Particle Swarm Optimization from the field of swarm intelligence, utilizing its superior optimization and searching abilities to obtain the most probable astronomical vessel position. In addition to being applicable to two-body fix, multi-body fix, and high-altitude observation problems, it is also less reliant on the initial dead reckoning position. Moreover, by introducing spatial data processing and display functions in a Geographical Information System, calculation results and chart work used in Circle of Position graphical positioning can both be integrated. As a result, in addition to avoiding tedious and complicated computational and graphical procedures, this work has more flexibility and is more robust when compared to other analytical approaches.

  3. The ancient Armenian calendars' connection with the celestial bodies

    Science.gov (United States)

    Broutian, G. H.

    2015-07-01

    The two oldest Armenian calendars - the Haykian and Protohaykian calendars were connected with observations of celestial bodies. Particularly since 2341 B.C. the heliacal rising of the first star of Orion was used to determine the day of the main holiday - Nawasard. Before that the observations of the same star were used in Protohaykian calendar to determine both the beginning and the end of the year. The year was determined as the duration of visibility of the star Betelgeuse. The year started with the heliacal rising of this star and ended with its heliacal setting. The remaining duration was considered to be out of the year. There are also evidences in Armenian medieval literary sources concerning the observations of heliacal rising and setting of Pleiades. An attempt was made to substantiate that the large symbol carved on the rock platform of the small hill in Metzamor also concerns to the Pleiades and shows the direction of heliacal rising of Pleiades.

  4. Eclipse. The celestial phenomenon that changed the course of history

    Science.gov (United States)

    Steel, Duncan

    Whether interpreted as an auspicious omen or a sentinel of doom, eclipses have had a profound effect upon our cultural development. The pattern that eclipses follow - a cycle, called the Saros - was actually calculated thousands of years ago. However, it is only with the help of modern computers that we have been able to analyze and appreciate the data. Eclipses provide unique opportunities for today's scientists to study such contrasting phenomena as the upper layers of the sun, the slowdown of our planet's spin rate, and the effects of celestial events on human psychology. In Eclipse, Duncan Steel expertly captures our continuing fascination with all manner of eclipses - including the familiar solar and lunar varieties and other kinds involving stars, planets, asteroids, and comets as well as distant galaxies and quasars. Steel helps us see that, in astronomical terms, eclipses are really rather straightforward affairs. Moving beyond the mysticism and the magic, the science of eclipses is revealed.

  5. Stellar aberration correction and thermoelastic compensation of Swarm μASC attitude observationsA comment to the Express Letter "Mysterious misalignments between geomagnetic and stellar reference frames seen in CHAMP and Swarm satellite measurements", by Stefan Maus

    Science.gov (United States)

    Herceg, M.; Jørgensen, P. S.; Jørgensen, J. L.

    2017-11-01

    The Swarm constellation of three satellites measures the magnetic signal of the Earth using both a Vector Field Magnetometer and an Absolute Scalar Magnetometer. A Micro Advanced Stellar Compass (μASC) mounted on a common, supposedly stable, optical bench precisely determines its inertial attitude. However, comparison of the Inter Boresight Angle shows a relative attitude variation between the μASC Camera Head Units. These misalignments between Camera Head Units and a geomagnetic reference frame cannot be explained by incorrect aberration correction (as theorized by Maus). Herceg et al. found them to be caused by thermal gradient sensitivity of the optical bench system, opposing the underlying assumption of perfect platform stability. The results after applying thermal corrections show significant decrease in root mean square, with Inter Boresight Angle of thermally corrected data being nearly flat and clean from any variation caused by thermoelastic effects.

  6. Celestial Navigation in the USA, Fiji, and Tunisia

    Science.gov (United States)

    Holbrook, Jarita C.

    2015-05-01

    Today there are many coastal communities that are home to navigators who use stars for position finding at night; I was, however, unaware of this fact when I began researching celestial navigation practices in 1997. My project focused on three communities: the Moce Islanders of Fiji, the Kerkennah Islanders in Tunisia, and the U.S. Navy officers and students at the United States Naval Academy, Annapolis, Maryland. My goal was to answer the question of why people continue to navigate by the stars, but also to understand the role of technology in their navigation practices. Using anthropology techniques of ethnography including participant observation, formal and informal interviews, audio and videotaping, I gathered data over five years at the three communities. I began by learning the details of how they use the stars for navigation. Next, I learned about who did the navigation and where they learned to navigate. I gathered opinions on various navigation aids and instruments, and opinions about the future of using the stars for navigation. I listened to the stories that they told about navigating. In the United States I worked in English, in Fiji, in Fijian and English, and in Tunisia, French and English. For the formal interviews I worked with translators. The navigators use stars for navigating today but the future of their techniques is not certain. Though practiced today, these celestial navigation traditions have undergone and continue to undergo changes. New navigational technologies are part of the stimulation for change, thus 'a meeting of different worlds' is symbolized by peoples encounters with these technologies.

  7. Contributions to reference systems from Lunar Laser Ranging using the IfE analysis model

    Science.gov (United States)

    Hofmann, Franz; Biskupek, Liliane; Müller, Jürgen

    2018-01-01

    Lunar Laser Ranging (LLR) provides various quantities related to reference frames like Earth orientation parameters, coordinates and velocities of ground stations in the Earth-fixed frame and selenocentric coordinates of the lunar retro-reflectors. This paper presents the recent results from LLR data analysis at the Institut für Erdmessung, Leibniz Universität Hannover, based on all LLR data up to the end of 2016. The estimates of long-periodic nutation coefficients with periods between 13.6 days and 18.6 years are obtained with an accuracy in the order of 0.05-0.7 milliarcseconds (mas). Estimations of the Earth rotation phase Δ UT are accurate at the level of 0.032 ms if more than 14 normal points per night are included. The tie between the dynamical ephemeris frame to the kinematic celestial frame is estimated from pure LLR observations by two angles and their rates with an accuracy of 0.25 and 0.02 mas per year. The estimated station coordinates and velocities are compared to the ITRF2014 solution and the geometry of the retro-reflector network with the DE430 solution. The given accuracies represent 3 times formal errors of the parameter fit. The accuracy for Δ UT is based on the standard deviation of the estimates with respect to the reference C04 solution.

  8. Stimulus reference frame and neural coding precision

    Czech Academy of Sciences Publication Activity Database

    Košťál, Lubomír

    2016-01-01

    Roč. 71, Apr 2016 (2016), s. 22-27 ISSN 0022-2496 R&D Projects: GA ČR(CZ) GA15-08066S Institutional support: RVO:67985823 Keywords : Fisher information * coding accuracy * measurement scale * Jeffreys prior Subject RIV: FH - Neurology Impact factor: 1.377, year: 2016

  9. Cognitive Frames of Reference and Strategic Thinking

    Science.gov (United States)

    1991-04-05

    Elliot Jaques and T. 0. Jacobs, whose Stratified Systems Theory (SST) links leadership requirements to organizational functions. SST emphasizes the...Strategic Managers , pp. 6-14. 6. Isenberg, p. 172; Jacobs and Jaques; J. G. Hunt, Toward Leadership Paradigm Expansion. 7. C. J. Whitehead and K. B...reverse if necessary and identify by block number) Using Stratified Systems Theory and the research on expertise as a conceptual framework, this study

  10. Numeric calculation of celestial bodies with spreadsheet analysis

    Science.gov (United States)

    Koch, Alexander

    2016-04-01

    The motion of the planets and moons in our solar system can easily be calculated for any time by the Kepler laws of planetary motion. The Kepler laws are a special case of the gravitational law of Newton, especially if you consider more than two celestial bodies. Therefore it is more basic to calculate the motion by using the gravitational law. But the problem is, that by gravitational law it is not possible to calculate the state of motion with only one step of calculation. The motion has to be numerical calculated for many time intervalls. For this reason, spreadsheet analysis is helpful for students. Skills in programmes like Excel, Calc or Gnumeric are important in professional life and can easily be learnt by students. These programmes can help to calculate the complex motions with many intervalls. The more intervalls are used, the more exact are the calculated orbits. The sutdents will first get a quick course in Excel. After that they calculate with instructions the 2-D-coordinates of the orbits of Moon and Mars. Step by step the students are coding the formulae for calculating physical parameters like coordinates, force, acceleration and velocity. The project is limited to 4 weeks or 8 lessons. So the calcualtion will only include the calculation of one body around the central mass like Earth or Sun. The three-body problem can only be shortly discussed at the end of the project.

  11. Archaeoastronomy as a Tool for Understanding Celestial Phenomena

    Science.gov (United States)

    Koufos, S.; Chatzichristou, E.

    2017-09-01

    To key feature of the wise and Modern Man was, is and will be the observation of the sky. The acquisition of knowledge by observing the majesty of the sky and studying these phenomena (stars, planets, sun, moon, comets, asteroids, meteors, orbits, seasons, etc.). decisively influenced all human cultures. Therefore the research on the astronomical knowledge and their usefulness for each culture may reveal important anthropological data. With this scientific article the ARCHAEOASTRONOMY engaged in a global dimension. With common ground among even distant peoples. The purpose of the speech is both the externalization of ARCHAEOASTRONOMY secondly the education and students interested in astronomy in a simple manner and methodology as used by our ancestors in order to better understand the basic rules of the celestial dome. Applied methods with the participation of students from local schools and experiments in ancient monuments in Rhodes existed before with great success since the beginning of 2000 and continues today enriching the resources and people of all ages, the island where noted and considered the "father" astronomy of Hipparchus, the island where construction probably the "Antikythera mechanism"

  12. Pseudo-set framing.

    Science.gov (United States)

    Barasz, Kate; John, Leslie K; Keenan, Elizabeth A; Norton, Michael I

    2017-10-01

    Pseudo-set framing-arbitrarily grouping items or tasks together as part of an apparent "set"-motivates people to reach perceived completion points. Pseudo-set framing changes gambling choices (Study 1), effort (Studies 2 and 3), giving behavior (Field Data and Study 4), and purchase decisions (Study 5). These effects persist in the absence of any reward, when a cost must be incurred, and after participants are explicitly informed of the arbitrariness of the set. Drawing on Gestalt psychology, we develop a conceptual account that predicts what will-and will not-act as a pseudo-set, and defines the psychological process through which these pseudo-sets affect behavior: over and above typical reference points, pseudo-set framing alters perceptions of (in)completeness, making intermediate progress seem less complete. In turn, these feelings of incompleteness motivate people to persist until the pseudo-set has been fulfilled. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  13. Nonmonotonic belief state frames and reasoning frames

    NARCIS (Netherlands)

    Engelfriet, J.; Herre, H.; Treur, J.

    1995-01-01

    In this paper five levels of specification of nonmonotonic reasoning are distinguished. The notions of semantical frame, belief state frame and reasoning frame are introduced and used as a semantical basis for the first three levels. Moreover, the semantical connections between the levels are

  14. Another frame, another game? : Explaining framing effects in economic games

    NARCIS (Netherlands)

    Gerlach, Philipp; Jaeger, B.; Hopfensitz, A.; Lori, E.

    2016-01-01

    Small changes in the framing of games (i.e., the way in which the game situation is described to participants) can have large effects on players' choices. For example, referring to a prisoner's dilemma game as the "Community Game" as opposed to the "Wall Street Game" can double the cooperation rate

  15. What's in a frame?

    DEFF Research Database (Denmark)

    Holmgreen, Lise-Lotte

    with the attitudes of readers and customers. The data for the analysis consist of newspaper articles from the Danish broadsheet press in the period of October 2008 to November 2009 as well as communication material from the Bank’s website. References Charteris-Black, Jonathan. 2004. Corpus Approaches to Critical....... Professional Discourse. London/NY: Continuum. Hallahan, Kirk. 1999. Seven models of framing: Implications for public relations. Journal of Public Relations Research 11 (3): 205-242. Kövecses, Zoltán. 1986. Metaphors of Anger, Pride and Love. Amsterdam: John Benjamins. Kövecses, Zoltán. 2006. Language, Mind...... how conservatives use language to dominate politics. UC Berkeley News, October 23 2003. Available at http://berkeley.edu/news/media/releases/2003/10/27_lakoff.shtml Lakoff, George and Mark Johnson. [1980] 2003. Metaphors We Live By. Chicago: The University of Chicago Press....

  16. Quotation and Framing

    DEFF Research Database (Denmark)

    Petersen, Nils Holger

    2010-01-01

    . In Black Angels the composer – among other well-known pieces of music – quotes the medieval dies irae sequence and the second movement of Schubert’s string quartet in D minor (D. 810). The musical and intermedial references are framed with striking modernistic sounds exploring instrumental possibilities...... far beyond the traditional, thus creating a framework of extreme contrasts. The paper will contextualize, analyze and interpret Black Angels – which the composer explicitly linked to the Vietnam War – in a broad context of music, intermediality, religious symbolism, and cultural memory, pointing......The purpose of this article is to discuss Crumb’s musical and intermedial intertextuality mainly through his Black Angels: Thirteen Images from the Dark Land for Electric String Quartet (1970), as an individually original but also representative compositional practice for the twentieth century...

  17. Framing of health information messages.

    Science.gov (United States)

    Akl, Elie A; Oxman, Andrew D; Herrin, Jeph; Vist, Gunn E; Terrenato, Irene; Sperati, Francesca; Costiniuk, Cecilia; Blank, Diana; Schünemann, Holger

    2011-12-07

    The same information about the evidence on health effects can be framed either in positive words or in negative words. Some research suggests that positive versus negative framing can lead to different decisions, a phenomenon described as the framing effect. Attribute framing is the positive versus negative description of a specific attribute of a single item or a state, for example, "the chance of survival with cancer is 2/3" versus "the chance of mortality with cancer is 1/3". Goal framing is the description of the consequences of performing or not performing an act as a gain versus a loss, for example, "if you undergo a screening test for cancer, your survival will be prolonged" versus "if you don't undergo screening test for cancer, your survival will be shortened". To evaluate the effects of attribute (positive versus negative) framing and of goal (gain versus loss) framing of the same health information, on understanding, perception of effectiveness, persuasiveness, and behavior of health professionals, policy makers, and consumers. We searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, issue 3 2007), MEDLINE (Ovid) (1966 to October 2007), EMBASE (Ovid) (1980 to October 2007), PsycINFO (Ovid) (1887 to October 2007). There were no language restrictions. We reviewed the reference lists of related systematic reviews, included studies and of excluded but closely related studies. We also contacted experts in the field. We included randomized controlled trials, quasi-randomised controlled trials, and cross-over studies with health professionals, policy makers, and consumers evaluating one of the two types of framing. Two review authors extracted data in duplicate and independently. We graded the quality of evidence for each outcome using the GRADE approach. We standardized the outcome effects using standardized mean difference (SMD). We stratified the analysis by the type of framing (attribute, goal) and conducted pre

  18. The Inner Meaning of Outer Space: Human Nature and the Celestial Realm

    Directory of Open Access Journals (Sweden)

    Timothy L. Hubbard

    2008-06-01

    Full Text Available Kant argued that humans possess a priori knowledge of space; although his argument focused on a physics of bodies, it also has implications for a psychology of beings. Many human cultures organize stars in the night sky into constellations (i.e., impose structure; attribute properties, behaviors, and abilities to objects in the celestial realm (i.e., impose meaning; and use perceived regularity in the celestial realms in development of calendars, long-range navigation, agriculture, and astrology (i.e., seek predictability and control. The physical inaccessibility of the celestial realm allows a potent source of metaphor, and also allows projection of myths regarding origin and ascension, places of power, and dwelling places of gods, immortals, and other souls. Developments in astronomy and cosmology infl uenced views of human nature and the place of humanity in the universe, and these changes parallel declines in egocentrism with human development. Views regarding alleged beings (e.g., angels, extraterrestrials from the celestial realm (and to how communicate with such beings are anthropocentric and ignore evolutionary factors in physical and cognitive development. It is suggested that in considering views and uses of the celestial realm, we learn not just about the universe, but also about ourselves. *

  19. The Future of Past Skies: Historical Celestial Cartography at the Adler Planetarium

    Science.gov (United States)

    Raposo, Pedro M. P.

    2018-01-01

    The Adler Planetarium is home to a world-class collection of scientific instruments, rare books and works on paper. Since 2014, Adler staff has been digitizing a wide selection of items relating to celestial cartography, including: more than 236 rare books and atlases; 97 works on paper; globes and other artifacts, amounting to 58 objects; and approximately 3,750 Carte du Ciel prints. This work has been carried out under the auspices of the Celestial Cartography Digitization Project (CCDP), which is sponsored by the National Endowment for the Humanities. This poster presentation will include: 1) an update on the project; 2) a description of related resources and tools available to the research community; 3) examples of how the Adler Planetarium is integrating the history of celestial cartography with its public programs; 4) an overview of a prospective citizen science project involving the identification of constellations in historical atlases and charts.

  20. Discretization of continuous frame

    Indian Academy of Sciences (India)

    other known continuous frames. Finally, we state and prove the assertions of the stability of perturbation in this concept. Keywords. Bounded operator; Hilbert space; continuous frame; atomic resolution of identity. 1. Introduction and preliminaries. As we know frames are more flexible tools to convey information than bases, ...

  1. Making students' frames explicit

    DEFF Research Database (Denmark)

    Nielsen, Louise Møller; Hansen, Poul Henrik Kyvsgaard

    2016-01-01

    Framing is a vital part of the design and innovation process. Frames are cognitive shortcuts (i.e. metaphors) that enable designers to connect insights about i.e. market opportunities and users needs with a set of solution principles and to test if this connection makes sense. Until now, framing...

  2. Decisions with endogenous frames

    NARCIS (Netherlands)

    Dalton, P.S.; Ghosal, S.

    2012-01-01

    We develop a model of decision-making with endogenous frames and contrast the normative implications of our model to those of choice theoretic models in which observed choices are determined by exogenous frames or ancillary conditions. We argue that, frames, though they may be taken as given by the

  3. Fusion frames and G-frames in Banach spaces

    Indian Academy of Sciences (India)

    Fusion frames and -frames in Hilbert spaces are generalizations of frames, and frames were extended to Banach spaces. In this article we introduce fusion frames, -frames, Banach -frames in Banach spaces and we show that they share many useful properties with their corresponding notions in Hilbert spaces. We also ...

  4. Frame-to-frame coherent GPU splatting

    OpenAIRE

    Grau Carrion, Sergi; Tost Pardell, Daniela

    2008-01-01

    Recently, several improvements of the classical splatting volume rendering technique have been proposed, specifically, GPU implementations that considerably speed it up. However, splatting time-varying data, even using the GPU, is still slow and not very suitable for interactive data exploration through time. In this paper, we propose a GPU-based viewaligned splatting algorithm that exploits frame-to-frame coherence to render time-varying volume datasets. Our method run-length enc...

  5. Multivariate wavelet frames

    CERN Document Server

    Skopina, Maria; Protasov, Vladimir

    2016-01-01

    This book presents a systematic study of multivariate wavelet frames with matrix dilation, in particular, orthogonal and bi-orthogonal bases, which are a special case of frames. Further, it provides algorithmic methods for the construction of dual and tight wavelet frames with a desirable approximation order, namely compactly supported wavelet frames, which are commonly required by engineers. It particularly focuses on methods of constructing them. Wavelet bases and frames are actively used in numerous applications such as audio and graphic signal processing, compression and transmission of information. They are especially useful in image recovery from incomplete observed data due to the redundancy of frame systems. The construction of multivariate wavelet frames, especially bases, with desirable properties remains a challenging problem as although a general scheme of construction is well known, its practical implementation in the multidimensional setting is difficult. Another important feature of wavelet is ...

  6. Illustrating the phaenomena celestial cartography in antiquity and the Middle Ages

    CERN Document Server

    Dekker, Elly

    2013-01-01

    In this volume all extant celestial maps and globes made before 1500 are described and analysed. It also discusses the astronomical sources involved in making these artefacts in antiquity, the Middle Ages, the Islamic world and the European Renaissance before 1500.

  7. Vladimir I Arnold - Collected Works Representations of Functions, Celestial Mechanics, and KAM Theory 1957-1965

    CERN Document Server

    Arnold, Vladimir I; Khesin, Boris

    2010-01-01

    Vladimir Arnold is one of the great mathematical scientists of our time. He is famous for both the breadth and the depth of his work. At the same time he is one of the most prolific and outstanding mathematical authors. This first volume of his Collected Works focuses on representations of functions, celestial mechanics, and KAM theory.

  8. Generation of dynamo waves by spatially separated sources in the Earth and other celestial bodies

    Science.gov (United States)

    Popova, E.

    2017-12-01

    The amplitude and the spatial configuration of the planetary and stellar magnetic field can changing over the years. Celestial bodies can have cyclic, chaotic or unchanging in time magnetic activity which is connected with a dynamo mechanism. This mechanism is based on the consideration of the joint influence of the alpha-effect and differential rotation. Dynamo sources can be located at different depths (active layers) of the celestial body and can have different intensities. Application of this concept allows us to get different forms of solutions and some of which can include wave propagating inside the celestial body. We analytically showed that in the case of spatially separated sources of magnetic field each source generates a wave whose frequency depends on the physical parameters of its source. We estimated parameters of sources required for the generation nondecaying waves. We discus structure of such sources and matter motion (including meridional circulation) in the liquid outer core of the Earth and active layers of other celestial bodies.

  9. A New Celestial Navigation Method for Spacecraft on a Gravity Assist Trajectory

    Directory of Open Access Journals (Sweden)

    Ning Xiaolin

    2013-01-01

    Full Text Available A practical and reliable capability for autonomous navigation needs to reduce operation cost, to improve operational efficiency, and to increase mission safety. Celestial navigation is a very attractive autonomous navigation solution for deep space spacecraft. There are mainly two kinds of celestial navigation methods: the direct calculation method and the filter method. The accuracy of the direct calculation method is low and very sensitive to the measurement noise. The filter method can provide a better navigation performance if a high accuracy dynamical model is available. However, the main practical problem existing in the autonomous celestial navigation of spacecraft on a gravity assist trajectory is that the accuracy of trajectory model is not enough to be used in the real navigation sometimes, which may introduce large estimation error and even cause filter divergence. To solve this problem, a new celestial navigation method is proposed in this paper, which effectively combines the direct calculation method and the filter method using an interacting multiple model unscented Kalman filter (IMMUKF. The ground experimental results demonstrate that this method can provide better navigation performance and higher reliability than the traditional direct calculation method and filter method.

  10. Frame independent cosmological perturbations

    Energy Technology Data Exchange (ETDEWEB)

    Prokopec, Tomislav; Weenink, Jan, E-mail: t.prokopec@uu.nl, E-mail: j.g.weenink@uu.nl [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, Leuvenlaan 4, 3585 CE Utrecht (Netherlands)

    2013-09-01

    We compute the third order gauge invariant action for scalar-graviton interactions in the Jordan frame. We demonstrate that the gauge invariant action for scalar and tensor perturbations on one physical hypersurface only differs from that on another physical hypersurface via terms proportional to the equation of motion and boundary terms, such that the evolution of non-Gaussianity may be called unique. Moreover, we demonstrate that the gauge invariant curvature perturbation and graviton on uniform field hypersurfaces in the Jordan frame are equal to their counterparts in the Einstein frame. These frame independent perturbations are therefore particularly useful in relating results in different frames at the perturbative level. On the other hand, the field perturbation and graviton on uniform curvature hypersurfaces in the Jordan and Einstein frame are non-linearly related, as are their corresponding actions and n-point functions.

  11. The Greatest Comets in History Broom Stars and Celestial Scimitars

    CERN Document Server

    Seargent, David A J

    2009-01-01

    Comets have fascinated and awed humankind since ancient times. Of the thousands of comets recorded throughout history, those deemed to have been the most spectacular have been described in the accounts of eyewitnesses and often recorded in official documents. This book introduces you to the greatest of the greats, starting with the comet in 372 B. C. called "Aristotle’s Comet" and ending with the spectacular appearance of McNaught’s Comet in 2007. There is an introductory chapter explaining what comets are and how they are classified, and correcting a few popular misconceptions. Later in the book you will read about the different returns of Halley’s Comet and the Kreutz sungrazing group, often called the kamikaze comets. There is even a chapter on comets that were visible in broad daylight. This book is unique. There are a few books on comets that make passing reference to some of the more famous or spectacular objects of the past, and a few catalogs with long lists of comets. But little detailed and de...

  12. Frame on frames: an annotated bibliography

    International Nuclear Information System (INIS)

    Wright, T.; Tsao, H.J.

    1983-01-01

    The success or failure of any sample survey of a finite population is largely dependent upon the condition and adequacy of the list or frame from which the probability sample is selected. Much of the published survey sampling related work has focused on the measurement of sampling errors and, more recently, on nonsampling errors to a lesser extent. Recent studies on data quality for various types of data collection systems have revealed that the extent of the nonsampling errors far exceeds that of the sampling errors in many cases. While much of this nonsampling error, which is difficult to measure, can be attributed to poor frames, relatively little effort or theoretical work has focused on this contribution to total error. The objective of this paper is to present an annotated bibliography on frames with the hope that it will bring together, for experimenters, a number of suggestions for action when sampling from imperfect frames and that more attention will be given to this area of survey methods research

  13. Development of a slim window frame made of glass fibre reinforced polyester

    DEFF Research Database (Denmark)

    Appelfeld, David; Hansen, Christian Skodborg; Svendsen, Svend

    2010-01-01

    This paper presents the development of an energy efficient window frame made of a glass fibre reinforced polyester (GFRP) material. Three frame proposals were considered. The energy and structural performances of the frames were calculated and compared with wooden and aluminium reference frames...... carried out an analysis of the potential energy savings of the frame. The calculations for a reference office building showed that the heating demand was considerably lower with a window made of GFRP than with the reference frames. It was found that GFRP is suitable for window frames, and windows made...

  14. Timber frame walls

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan de Place; Brandt, Erik

    2010-01-01

    A ventilated cavity is usually considered good practice for removing moisture behind the cladding of timber framed walls. Timber frame walls with no cavity are a logical alternative as they are slimmer and less expensive to produce and besides the risk of a two-sided fire behind the cladding...

  15. Modern Steel Framed Schools.

    Science.gov (United States)

    American Inst. of Steel Construction, Inc., New York, NY.

    In view of the cost of structural framing for school buildings, ten steel-framed schools are examined to review the economical advantages of steel for school construction. These schools do not resemble each other in size, shape, arrangement or unit cost; some are original in concept and architecture, and others are conservative. Cost and…

  16. Discretization of continuous frame

    Indian Academy of Sciences (India)

    Home; Journals; Proceedings – Mathematical Sciences; Volume 122; Issue 2 ... In this paper we consider the notion of continuous frame of subspaces and define a new concept of continuous frame, entitled continuous atomic resolution of identity, for arbitrary Hilbert space H which has a countable reconstruction formula.

  17. The Frame Game

    Science.gov (United States)

    Edwards, Michael Todd; Cox, Dana C.

    2011-01-01

    In this article, the authors explore framing, a non-multiplicative technique commonly employed by students as they construct similar shapes. When students frame, they add (or subtract) a "border" of fixed width about a geometric object. Although the approach does not yield similar shapes in general, the mathematical underpinnings of…

  18. Multimodal news framing effects

    NARCIS (Netherlands)

    Powell, T.E.

    2017-01-01

    Visuals in news media play a vital role in framing citizens’ political preferences. Yet, compared to the written word, visual images are undervalued in political communication research. Using framing theory, this thesis redresses the balance by studying the combined, or multimodal, effects of visual

  19. Thinking inside the frame

    DEFF Research Database (Denmark)

    Knudsen, Sanne

    2017-01-01

    The humanities, the natural and social sciences all represent advanced and systematic knowledge production—and they all receive public funding for doing so. However, although the field of public understanding of science has been well established for decades, similar research attention has not been...... directed at the humanities. The purpose of this study is to argue the case for further research of public understanding of the humanities and to take a first step in that direction by presenting a study of the framing of the humanities in Danish print news media. Different framings of the humanities...... are analyzed. Despite the differences in the issue-specific frames, the generic framing of the humanities shared by most articles is as follows: 75% explicitly frame the humanities as deficit, while the remaining 25% are more neutral. Consequently, if newspapers constitute the only source of information...

  20. Urgensi Penerapan Celestial Management Bagi Sumber Daya Manusia Di Bank Syariah

    Directory of Open Access Journals (Sweden)

    Trimulato Trimulato

    2016-05-01

    Full Text Available Abstract: Islamic banking currently has a strong legal law with the presence of the law number 21 of 2008 on banking syari'ah.Hal This adversely affects the existence of the banking Shari'ah are increasingly in demand by many. Islamic bank continues to grow and continue to open office services in various areas. Thus iru development of Islamic banks must be matched with adequate resources and qualified. Noted labor in Islamic banks continued to grow, from November 2014 to November 2015 grew to 23.51%. Not only the quantity but the quality should also be considered, it takes a celestial concept should be applied for the Management of human resources in Islamic banks. This paper uses a descriptive qualitative limitations in this paper is focused on the human resources that exist in the Islamic bank. The need for the application of celestial management for human resources in the bank syariahi. The results of this paper that the human resources in Islamic banks is growing, then the need for the application of celestial management for human resources in Islamic banks to create good quality. Because the Islamic bank is an institution whose business is inseparable from the rule of religion or spiritual aspect. Abstrak: Perbankan syari’ah saat ini telah memiliki payung hukum yang kuat dengan hadirnya undang-undang nomor 21 tahun 2008 tentang perbankan syari’ah.Hal ini sangat berpengaruh terhadap eksistensi dari perbankan syari’ah yang semakin diminati oleh banyak kalangan. Bank syari’ah terus berkembang dan terus membuka layanan kantor di berbagai daerah. Maka dari iru perkembangan bank syariah harus diimbangi dengan sumber daya yang mencukupi dan berkualitas. Tercatat tenaga kerja di bank syariah terus bertambah, dari November 2014 sampai November 2015 mengalami pertumbuhan hingga 23,51%. Tidak hanya dari kuantitas tapi kualitas juga harus diperhatikan, dibutuhkan sebuah konsep celestial manajement yang harus diterapkan bagi sumber daya manusia

  1. Parametrizing Finite Frames and Optimal Frame Completions

    Science.gov (United States)

    2012-12-01

    n = n ′( ∫ ∞ −∞ n pn(n)dn )( ∫ ∞ −∞ n′ pn′(n′)dn′ ) n , n′ =  var (n) n = n′ 0 n , n′ . (6.3) Substituting (6.3) into (6.2) gives...frames,” in Proceedings of the SPIE Conference on Wavelets : Applications in Signal and Image Processing X, 371-380 (November 2003). [10] Casazza, P. G

  2. Framing Gangnam Style

    Directory of Open Access Journals (Sweden)

    Hyunsun Catherine Yoon

    2017-08-01

    Full Text Available This paper examines the way in which news about Gangnam Style was framed in the Korean press. First released on 15th July 2012, it became the first video to pass two billion views on YouTube. 400 news articles between July 2012 and March 2013 from two South Korean newspapers - Chosun Ilbo and Hankyoreh were analyzed using the frame analysis method in five categories: industry/economy, globalization, cultural interest, criticism, and competition. The right-left opinion cleavage is important because news frames interact with official discourses, audience frames and prior knowledge which consequently mediate effects on public opinion, policy debates, social movement and individual interpretations. Whilst the existing literature on Gangnam Style took rather holistic approach, this study aimed to fill the lacuna, considering this phenomenon as a dynamic process, by segmenting different stages - recognition, spread, peak and continuation. Both newspapers acknowledged Gangnam Style was an epochal event but their perspectives and news frames were different; globalization frame was most frequently used in Chosun Ilbo whereas cultural interest frame was most often used in Hankyoreh. Although more critical approaches were found in Hankyoreh, reflecting the right-left opinion cleavage, both papers lacked in critical appraisal and analysis of Gangnam Style’s reception in a broader context of the new Korean Wave.

  3. The space technological applications of the celestial mechanical Lagrange points in the protection of environment

    International Nuclear Information System (INIS)

    Horvath, A.

    1993-01-01

    Space-technology can in the future help to solve two burning global problems of mankind: global warming and the storage of radioactive waste. In the space technological solution of these problems the celestial mechanical Lagrange points of the Sun-Earth and Earth-Moon systems can play an important role. Therefore the celestial mechanical theory and computer simulation of the nature of Lagrange points have great importance in some aspects of the protection of the environment, too. The two examples given, propose: storage of radioactive wastes in the stable Lagrange points L 4 and L 5 reduction of the global warming by positioning satellites with large mirrors in the collinear Lagrange point L 2 thus shadowing the incoming solar radiation. (orig./HM)

  4. Framing (implicitly) matters

    DEFF Research Database (Denmark)

    Anderson, Joel; Antalikova, Radka

    2014-01-01

    Denmark is currently experiencing the highest immigration rate in its modern history. Population surveys indicate that negative public attitudes toward immigrants actually stem from attitudes toward their (perceived) Islamic affiliation. We used a framing paradigm to investigate the explicit...... and implicit attitudes of Christian and Atheist Danes toward targets framed as Muslims or as immigrants. The results showed that explicit and implicit attitudes were more negative when the target was framed as a Muslim, rather than as an immigrant. Interestingly, implicit attitudes were qualified...

  5. International negotiations of natural resources on the moon and other celestial bodies : future cooperation or conflict?

    OpenAIRE

    Eymork, Tania Patricia

    2012-01-01

    This thesis aims to assess the degree to which one can expect conflict or cooperation over the natural resources on the Moon and other celestial bodies in the future. By describing and exploring how the emerging global space industry may benefit humankind, it covers existing international space treaties and how fairer administration may help to eradicate poverty by, amongst other things, providing a clean source of environmentally friendly energy. This sixtyyear young industry is redeployi...

  6. On transforms between Gabor frames and wavelet frames

    DEFF Research Database (Denmark)

    Christensen, Ole; Goh, Say Song

    2013-01-01

    We describe a procedure that enables us to construct dual pairs of wavelet frames from certain dual pairs of Gabor frames. Applying the construction to Gabor frames generated by appropriate exponential Bsplines gives wavelet frames generated by functions whose Fourier transforms are compactly...... supported splines with geometrically distributed knot sequences. There is also a reverse transform, which yields pairs of dual Gabor frames when applied to certain wavelet frames....

  7. Risk of Adverse Health and Performance Effects of Celestial Dust Exposure

    Science.gov (United States)

    Scully, Robert R.; Meyers, Valerie E.

    2015-01-01

    Crew members can be directly exposed to celestial dust in several ways. After crew members perform extravehicular activities (EVAs), they may introduce into the habitat dust that will have collected on spacesuits and boots. Cleaning of the suits between EVAs and changing of the Environmental Control Life Support System filters are other operations that could result in direct exposure to celestial dusts. In addition, if the spacesuits used in exploration missions abrade the skin, as current EVA suits have, then contact with these wounds would provide a source of exposure. Further, if celestial dusts gain access to a suit's interior, as was the case during the Apollo missions, the dust could serve as an additional source of abrasions or enhance suit-induced injuries. When a crew leaves the surface of a celestial body and returns to microgravity, the dust that is introduced into the return vehicle will "float," thus increasing the opportunity for ocular and respiratory injury. Because the features of the respirable fraction of lunar dusts indicate they could be toxic to humans, NASA conducted several studies utilizing lunar dust simulants and authentic lunar dust to determine the unique properties of lunar dust that affect physiology, assess the dermal and ocular irritancy of the dust, and establish a permissible exposure limit for episodic exposure to airborne lunar dust during missions that would involve no more than 6 months stay on the lunar surface. Studies, with authentic lunar soils from both highland (Apollo 16) and mare (Apollo17) regions demonstrated that the lunar soil is highly abrasive to a high fidelity model of human skin. Studies of lunar dust returned during the Apollo 14 mission from an area of the moon in which the soils were comprised of mineral constituents from both major geological regions (highlands and mares regions) demonstrated only minimal ocular irritancy, and pulmonary toxicity that was less than the highly toxic terrestrial crystalline

  8. The Hands of the Pleiades: The Celestial Clock in the Classical Arabic Poetry of Dhū al-Rumma

    Science.gov (United States)

    Adams, W. B.

    2011-06-01

    In the desert poetry of Dhū al-Rumma (d. 117 AH/735 CE), astronomical phenomena sometimes function as familiar celestial timepieces that indicate the poetic timeframe literally and accurately. The literary, lexical, floral and astronomical analyses of a selection from this poetry illustrate the role of the Pleiades star cluster as a celestial clock and illuminate the utility of naked-eye astronomy in interpreting Arabic poetry of the early Islamic period.

  9. Leadership in Community Schools: A Frame Analysis.

    Science.gov (United States)

    Rice, Daniel; Harris, Mary M.

    2003-01-01

    Creating community schools requires changes in collaborating organizations. The authors describe how a major project has been initiated and sustained from the perspectives of key leaders/participants. They discuss four different perspectives or frames for identifying organizational change. (Contains 13 references.) (Author)

  10. Operator representations of frames

    DEFF Research Database (Denmark)

    Christensen, Ole; Hasannasab, Marzieh

    2017-01-01

    The purpose of this paper is to consider representations of frames {fk}k∈I in a Hilbert space ℋ of the form {fk}k∈I = {Tkf0}k∈I for a linear operator T; here the index set I is either ℤ or ℒ0. While a representation of this form is available under weak conditions on the frame, the analysis...... of the properties of the operator T requires more work. For example it is a delicate issue to obtain a representation with a bounded operator, and the availability of such a representation not only depends on the frame considered as a set, but also on the chosen indexing. Using results from operator theory we show...... that by embedding the Hilbert space ℋ into a larger Hilbert space, we can always represent a frame via iterations of a bounded operator, composed with the orthogonal projection onto ℋ. The paper closes with a discussion of an open problem concerning representations of Gabor frames via iterations of a bounded...

  11. What's in a Frame?

    DEFF Research Database (Denmark)

    Holmgreen, Lise-Lotte

    Maintaining a good image and reputation in the eyes of stakeholders is vital to the organisation. Thus, in its corporate communication and discourse the organisation will seek to present or frame itself as favourably as possible while observing regulations stipulating accuracy and precision...... in the information given. However, in this process the organisation is not operating in a social vacuum but is continuously interacting with various players, such as the media, for its textual and discursive creation (Gunnarsson 2009). In this presentation, I will focus on the role of this interaction in framing...... an organisation, and hence in shaping the image projected to the public. Framing is here understood as the selection of ‘some aspects of perceived reality … [making] them more salient in the communication text, in such a way as to promote a particular problem definition, causal interpretation, moral evaluation...

  12. Framing the Newspaper Crisis

    DEFF Research Database (Denmark)

    Bruggemann, Michael; Humprecht, Edda; Kleis, Rasmus

    2016-01-01

    This article argues that discourses of a newspaper crisis should not be regarded simply as descriptions of the actual state of the press but also as a means by which strategic actors frame the situation. The emerging frames can have substantial consequences for media policy making. The study...... as well as a qualitative analysis of policy documents and relevant media coverage. The study demonstrates that debates on the newspaper crisis are only partly influenced by (1) economic realities and (2) media policy traditions in the six countries but also reflect (3) the strategic motives of powerful...... actors and (4) the diffusion of frames across borders, particularly those coming from the United States. A transnationally uniform paradigm emerges according to which the state is expected to play the role of a benevolent but mostly passive bystander, while media companies are expected to tackle...

  13. New Characterizations of Fusion Frames (Frames of Subspaces)

    Indian Academy of Sciences (India)

    In this article, we give new characterizations of fusion frames, on the properties of their synthesis operators, on the behavior of fusion frames under bounded operators with closed range, and on erasures of subspaces of fusion frames. Furthermore we show that every fusion frame is the image of an orthonormal fusion basis ...

  14. New characterizations of fusion frames (frames of subspaces)

    Indian Academy of Sciences (India)

    Abstract. In this article, we give new characterizations of fusion frames, on the properties of their synthesis operators, on the behavior of fusion frames under bounded operators with closed range, and on erasures of subspaces of fusion frames. Furthermore we show that every fusion frame is the image of an orthonormal ...

  15. Timber frame walls

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan de Place; Brandt, Erik

    2010-01-01

    A ventilated cavity is usually considered good practice for removing moisture behind the cladding of timber framed walls. Timber frame walls with no cavity are a logical alternative as they are slimmer and less expensive to produce and besides the risk of a two-sided fire behind the cladding...... is reduced. To investigate the possibilities, full-size wall elements with wooden cladding and different cavity design, type of cladding and type of wind barrier were exposed to natural climate on the outside and to a humid indoor climate on the inside. During the exposure period parts of the vapour barrier...

  16. Framing financial culture

    DEFF Research Database (Denmark)

    Just, Sine Nørholm; Mouton, Nicolaas T.O.

    2014-01-01

    between competing frames leads to the conclusion that this political “blame game” is related to struggles over how to define the scandal, how to conceptualize its causes, and policy recommendations. Banks may have lost the battle of “Liborgate,” but the war over the meaning of financial culture is far...... from over. Originality/value – The paper is theoretically and methodologically original in its combination of the theories of framing and stasis, and it provides analytical insights into how sense is made of financial culture in the wake of the financial crisis....

  17. Video frame processor

    International Nuclear Information System (INIS)

    Joshi, V.M.; Agashe, Alok; Bairi, B.R.

    1993-01-01

    This report provides technical description regarding the Video Frame Processor (VFP) developed at Bhabha Atomic Research Centre. The instrument provides capture of video images available in CCIR format. Two memory planes each with a capacity of 512 x 512 x 8 bit data enable storage of two video image frames. The stored image can be processed on-line and on-line image subtraction can also be carried out for image comparisons. The VFP is a PC Add-on board and is I/O mapped within the host IBM PC/AT compatible computer. (author). 9 refs., 4 figs., 19 photographs

  18. Frame scaling function sets and frame wavelet sets in Rd

    International Nuclear Information System (INIS)

    Liu Zhanwei; Hu Guoen; Wu Guochang

    2009-01-01

    In this paper, we classify frame wavelet sets and frame scaling function sets in higher dimensions. Firstly, we obtain a necessary condition for a set to be the frame wavelet sets. Then, we present a necessary and sufficient condition for a set to be a frame scaling function set. We give a property of frame scaling function sets, too. Some corresponding examples are given to prove our theory in each section.

  19. ASTEP South: An Antarctic Search for Transiting ExoPlanets around the celestial South pole

    OpenAIRE

    Crouzet , Nicolas; Guillot , Tristan; Agabi , Karim; Rivet , Jean-Pierre; Bondoux , Erick; Challita , Zalpha; Fanteï-Caujolle , Yan; Fressin , François; Mékarnia , Djamel; Schmider , François-Xavier; Valbousquet , Franck; Blazit , Alain; Bonhomme , Serge; Abe , Lyu; Daban , Jean-Baptiste

    2009-01-01

    ASTEP South is the first phase of the ASTEP project (Antarctic Search for Transiting ExoPlanets). The instrument is a fixed 10 cm refractor with a 4kx4k CCD camera in a thermalized box, pointing continuously a 3.88 degree x 3.88 degree field of view centered on the celestial South pole. ASTEP South became fully functional in June 2008 and obtained 1592 hours of data during the 2008 Antarctic winter. The data are of good quality but the analysis has to account for changes in the point spread f...

  20. Celestial harvest 300-plus showpieces of the heavens for telescope viewing and contemplation

    CERN Document Server

    Mullaney, James

    2012-01-01

    This book describes over 300 celestial wonders that can be viewed with common binoculars and low-power ""backyard"" telescopes incorporating refractors and reflectors.In addition to such showpieces as the Andromeda Galaxy, the largest and brightest of all galaxies after the Milky Way, and the Blue Snowball, one of the autumn sky's outstanding planetary nebulas, over 20 other special objects are listed and characterized, many of which are visible to the unaided eye on a dark, clear night.The sun, moon, Venus, Mars, Jupiter, Saturn, and other members of the earth's solar system are also describ

  1. To frame is to explain: a deductive frame-analysis of Dutch and French climate change coverage during the annual UN Conferences of the Parties.

    Science.gov (United States)

    Dirikx, Astrid; Gelders, Dave

    2010-11-01

    This study examines the way Dutch and French newspapers frame climate change during the annual United Nations Conferences of the Parties. The methods used in previous studies on the framing of climate change do not allow for general cross-national comparisons. We conduct a quantitative deductive framing analysis on 257 quality Dutch and French newspaper articles between 2001 and 2007. Both countries' newspapers seem to frame climate change through mainly the same lens. The majority of the articles make reference to the consequences of the (non-)pursuit of a certain course of action and of possible losses and gains (consequences frame). Additionally, many articles mention the need for urgent actions, refer to possible solutions and suggest that governments are responsible for and/or capable of alleviating climate change problems (responsibility frame). Finally, the conflict frame was found to be used less often than the aforementioned frames, but more regularly than the human interest frame.

  2. Frames and extension problems I

    DEFF Research Database (Denmark)

    Christensen, Ole

    2014-01-01

    In this article we present a short survey of frame theory in Hilbert spaces. We discuss Gabor frames and wavelet frames and set the stage for a discussion of various extension principles; this will be presented in the article Frames and extension problems II (joint with H.O. Kim and R.Y. Kim)....

  3. The Cage; Framing Dad

    DEFF Research Database (Denmark)

    Kau, Edvin

    2012-01-01

    Unfolding his story very gradually and arousing the viewer’s curiosity, Sitaru invites the audience to investigate the parents’ and the boy’s mutual positions in their small flat, as well as the various layers of their conversations, through such means as framing, editing style, and the use...

  4. Framing ‘fracking’

    NARCIS (Netherlands)

    Williams, Laurence; Macnaghten, Philip; Davies, Richard; Curtis, Sarah

    2017-01-01

    The prospect of fracking in the United Kingdom has been accompanied by significant public unease. We outline how the policy debate is being framed by UK institutional actors, finding evidence of a dominant discourse in which the policy approach is defined through a deficit model of public

  5. Framing the Oscars live

    DEFF Research Database (Denmark)

    Haastrup, Helle Kannik

    2016-01-01

    How is the global media event of the Oscars localised through the talk show on Danish television? How are both the mediated film star and the special brand of Hollywood celebrity culture addressed by the cultural intermediaries in the Danish framing? These are the questions I propose to answer...

  6. Framing Light Rail Projects

    DEFF Research Database (Denmark)

    Olesen, Mette

    2014-01-01

    In Europe, there has been a strong political will to implement light rail. This article contributes to the knowledge concerning policies around light rail by analysing how local actors frame light rail projects and which rationalities and arguments are present in this decision-making process...

  7. Framing the Manager

    DEFF Research Database (Denmark)

    Holmgreen, Lise-Lotte

    2013-01-01

    ). In this process, framing (Evans & Green 2006; Fillmore 1982; Kövecses 2006; Lakoff 1987, 1996) plays a salient role in conceptualising the profile and qualities of the preferred candidate, drawing on established cultural models of what constitutes the perfect leader. Thus, in a Danish setting we may talk of two...

  8. Institutional Justification in Frames

    DEFF Research Database (Denmark)

    Baden, Christian; Schultz, Friederike

    Crises – such as the BP oil spill in the Gulf of Mexico (2010) – are moments in which conventional interpretations break down. This paper analyzes the dynamics of the re-construction and stabilization of meaning in the public debate and assesses how BP’s strategic framing affected the emerging...

  9. Framing Canadian federalism

    National Research Council Canada - National Science Library

    Saywell, John; Anastakis, Dimitry; Bryden, Penny E

    2009-01-01

    ... the pervasive effects that federalism has on Canadian politics, economics, culture, and history, and provide a detailed framework in which to understand contemporary federalism. Written in honour of John T. Saywell's half-century of accomplished and influential scholarly work and teaching, Framing Canadian Federalism is a timely and fitting t...

  10. Sparse Matrices in Frame Theory

    DEFF Research Database (Denmark)

    Lemvig, Jakob; Krahmer, Felix; Kutyniok, Gitta

    2014-01-01

    Frame theory is closely intertwined with signal processing through a canon of methodologies for the analysis of signals using (redundant) linear measurements. The canonical dual frame associated with a frame provides a means for reconstruction by a least squares approach, but other dual frames...... yield alternative reconstruction procedures. The novel paradigm of sparsity has recently entered the area of frame theory in various ways. Of those different sparsity perspectives, we will focus on the situations where frames and (not necessarily canonical) dual frames can be written as sparse matrices...

  11. Wavelet frames and their duals

    DEFF Research Database (Denmark)

    Lemvig, Jakob

    2008-01-01

    This thesis is concerned with computational and theoretical aspects of wavelet frame analysis in higher dimensions and, in particular, with the study of so-called dual frames of wavelet frames. A frame is a system of "simple" functions or building blocks which deliver ways of analyzing signals....... The signals are then represented by linear combinations of the building blocks with coefficients found by an associated frame, called a dual frame. A wavelet frame is a frame where the building blocks are stretched (dilated) and translated versions of a single function; such a frame is said to have wavelet...... structure. The dilation of the wavelet building blocks in higher dimension is done via a square matrix which is usually taken to be integer valued. In this thesis we step away from the "usual" integer, expansive dilation and consider more general, expansive dilations. In most applications of wavelet frames...

  12. Spatio-Temporal Modeling of the Earth Events and Moving of Celestial Bodies

    Science.gov (United States)

    Bulatova, Natalia P.

    2011-09-01

    It is well known that periodical and cyclical movements of cosmic sources of gravitation considerably affect Earth's geospheres (atmosphere, hydrosphere, crust, etc.) by producing tides and related phenomena, as well as the state of tectonic blocks, lithosphere plates and deep crust fractures. The result of such influence may be earthquakes and other catastrophes. Nowadays, the question modeling of geophysical processes is considerably actual. Thus studies in area of Earth' sciences have been moved from practice of observation of separate phenomena to the systematic quantitative investigation in interdisciplinary areas. A system of two modules is proposed by the author each using its own system of coordinates: (1) the model of three-dimensional spherical body of the Earth with the system of coordinates (III) including the time of events that happened on the Earth and (2) a compact model of the relative motion of celestial bodies in space and time as vectors that are changing their directions. Note the data bases of the Earth sciences have been used to construct the module (1), while the module (2) has been built using astronomic parameters of celestial bodies. The module (2) is known as "Method of moving source" (MDS) [1, 2]. As a result, on the basis of systematization, joint analysis and complexity of cosmic data and databases of Earth sciences the cause-and-effect relations between events on Earth and space bodies are established.

  13. Some relationship between G-frames and frames

    Directory of Open Access Journals (Sweden)

    Mehdi Rashidi-Kouchi

    2015-06-01

    Full Text Available In this paper we proved that every g-Riesz basis for Hilbert space $H$ with respect to $K$ by adding a condition is a Riesz basis for Hilbert $B(K$-module $B(H,K$. This is an extension of [A. Askarizadeh,M. A. Dehghan, {em G-frames as special frames}, Turk. J. Math., 35, (2011 1-11]. Also, we derived similar results for g-orthonormal and orthogonal bases. Some relationships between dual frame, dual g-frame and exact frame and exact g-frame are presented too.

  14. FishFrame

    DEFF Research Database (Denmark)

    Degel, Henrik; Jansen, Teunis

    2006-01-01

    . Development and test of software modules can be done once and reused by all. The biggest challenge in this is not technical – it is in organisation, coordination and trust. This challenge has been addressed by FishFrame - a web-based datawarehouse application. The “bottom-up” approach with maximum involvement...... for fixed reoccurring tasks like assessment working groups, data are often late and the quality can be unsatisfactory. The current situation of this “semi-manual distributed datawarehouse” can be improved technically. Methods for quality control, raising and calculation can be discussed and unified...... value to users and in the end improves the way we work with our data. FishFrame version 4.2 is presented and the lessons learned from the process are discussed....

  15. On Fourier frames

    OpenAIRE

    Ortega-Cerda, Joaquim; Seip, Kristian

    2000-01-01

    We solve the problem of Duffin and Schaeffer (1952) of characterizing those sequences of real frequencies which generate Fourier frames. Equivalently, we characterize the sampling sequences for the Paley-Wiener space. The key step is to connect the problem with de Branges' theory of Hilbert spaces of entire functions. We show that our description of sampling sequences permits us to obtain a classical inequality of H. Landau as a consequence of Pavlov's description of Riesz bases of complex ex...

  16. Framing a Bank

    DEFF Research Database (Denmark)

    Holmgreen, Lise-Lotte

    2012-01-01

    Danish bank, Danske Bank, during the 2008 financial crisis and hence in shaping its image projected to the public. Through the study of a number of semantic frames adopted by the Danish print press and those adopted by the Bank, this article will argue for the constructions of the press putting...... considerable strain on the Bank and its image, leading it to reconsider its previous strategy of denial of responsibility...

  17. Optical loop framing

    International Nuclear Information System (INIS)

    Kalibjian, R.; Chong, Y.P.; Prono, D.S.; Cavagnolo, H.R.

    1984-06-01

    The ATA provides an electron beam pulse of 70-ns duration at a 1-Hz rate. Our present optical diagnostics technique involve the imaging of the visible light generated by the beam incident onto the plant of a thin sheet of material. It has already been demonstrated that the light generated has a sufficiently fast temporal reponse in performing beam diagnostics. Notwithstanding possible beam emittance degradation due to scattering in the thin sheet, the observation of beam spatial profiles with relatively high efficiencies has provided data complementary to that obtained from beam wall current monitors and from various x-ray probes and other electrical probes. The optical image sensor consists of a gated, intensified television system. The gate pulse of the image intensifier can be appropriately delayed to give frames that are time-positioned from the head to the tail of the beam with a minimum gate time of 5-ns. The spatial correlation of the time frames from pulse to pulse is very good for a stable electron beam; however, when instabilities do occur, it is difficult to properly assess the spatial composition of the head and the tail of the beam on a pulse-to-pulse basis. Multiple gating within a pulse duration becomes desirable but cannot be performed because the recycle time (20-ms) of the TV system is much longer than the beam pulse. For this reason we have developed an optical-loop framing technique that will allow the recording of two frames within one pulse duration with our present gated/intensified TV system

  18. Density of Gabor Frames

    DEFF Research Database (Denmark)

    Christensen, Ole; Heil, Christopher; Deng, Baiqiao

    1999-01-01

    A Gabor system is a set of time-frequency shifts S(g, Lambda) = {e(2 pi ibx) g(x - a)}((a,b)is an element of Lambda) of a function g is an element of L-2(R-d). We prove that if a finite union of Gabor systems boolean (ORk=1S)-S-r(g(k), Lambda(k)) forms a frame for L-2(R-d) then the lower and upper...

  19. Density of Gabor Frames

    DEFF Research Database (Denmark)

    Christensen, Ole; Heil, C.; Deng, B.

    1997-01-01

    A Gabor system is a set of time-frequency shifts$S(g,\\Lambda) = \\{e^{2\\pi i b x} g(x-a)\\}_{(a,b) \\in \\Lambda}$of a function $g \\in L^2({\\bold R}^d)$.We prove that if a finite union of Gabor systems$\\bigcup_{k=1}^r S(g_k,\\Lambda_k)$, with arbitrary sequences $\\Lambda_k$,forms a frame for $L^2({\\bold...

  20. On the oscillatory motion of a celestial body, time, speed, and the forces acting on a body moving along the solar system orbit

    Directory of Open Access Journals (Sweden)

    Kulik V.I.

    2016-06-01

    Full Text Available the article aims to consider the reason why a celestial body moves along the solar system orbit and the features of this movement. Moreover, the paper discovers those potential energy systems, which manage the movement of a celestial body. Critical parameters’ changes of a celestial body rotating around the Center are graphically represented. All the parameters in algebraic expressions are considered to be dependent from each other and, primarily, from the proximity of «radius-vector» of a celestial body place and the focus of an elliptic orbit.

  1. serialising languages: satellite-framed, verb-framed or neither

    African Journals Online (AJOL)

    George Saad

    Ghana Journal of Linguistics 2.1: 19-38 (2013). 19. SERIALISING LANGUAGES: SATELLITE-FRAMED, VERB-FRAMED OR NEITHER. Felix K. Ameka and James Essegbey. Abstract. The diversity in the coding of the core schema of motion, i.e., Path, has led to a traditional typology of languages into verb-framed and ...

  2. Framing Vision: An Examination of Framing, Sensegiving, and Sensemaking during a Change Initiative

    Science.gov (United States)

    Hamilton, William

    2016-01-01

    The purpose of this short article is to review the findings from an instrumental case study that examines how a college president used what this article refers to as "frame alignment processes" to mobilize internal and external support for a college initiative--one that achieved success under the current president. Specifically, I…

  3. Conformal frame dependence of inflation

    International Nuclear Information System (INIS)

    Domènech, Guillem; Sasaki, Misao

    2015-01-01

    Physical equivalence between different conformal frames in scalar-tensor theory of gravity is a known fact. However, assuming that matter minimally couples to the metric of a particular frame, which we call the matter Jordan frame, the matter point of view of the universe may vary from frame to frame. Thus, there is a clear distinction between gravitational sector (curvature and scalar field) and matter sector. In this paper, focusing on a simple power-law inflation model in the Einstein frame, two examples are considered; a super-inflationary and a bouncing universe Jordan frames. Then we consider a spectator curvaton minimally coupled to a Jordan frame, and compute its contribution to the curvature perturbation power spectrum. In these specific examples, we find a blue tilt at short scales for the super-inflationary case, and a blue tilt at large scales for the bouncing case

  4. MedlinePlus FAQ: Framing

    Science.gov (United States)

    ... URL of this page: https://medlineplus.gov/faq/framing.html I'd like to link to MedlinePlus, ... M. encyclopedia. Our license agreements do not permit framing of their content from our site. For more ...

  5. The PgaFrame - a frame for parallel genetic algorithms

    OpenAIRE

    Petit Silvestre, Jordi

    1997-01-01

    The PgaFrame offers to non-expert users the possibility to solve optimization problems via genetic algorithms on parallel computers. This frame has appeared as the natural fusion of two different projects: PgaPack and Frames. The PgaFrame combines the major features of these projects: it integrates the capabilities to specify genetic algorithms offered by the PgaPack library and the support of Frames to the easy and portable programming of parallel machines. In this way, a complex fra...

  6. Brain potentials associated with the outcome processing in framing effects.

    Science.gov (United States)

    Ma, Qingguo; Feng, Yandong; Xu, Qing; Bian, Jun; Tang, Huixian

    2012-10-24

    Framing effect is a cognitive bias referring to the phenomenon that people respond differently to different but objectively equivalent descriptions of the same problem. By measuring event-related potentials, the present study aimed to investigate the neural mechanisms underlying the framing effect, especially how the negative and positive frames influence the outcome processing in our brain. Participants were presented directly with outcomes framed either positively in terms of lives saved or negatively in terms of lives lost in large and small group conditions, and were asked to rate the favorableness of each of them. The behavioral results showed that the framing effect occurred in both group size conditions, with more favorable evaluations associated with positive framing. Compared with outcomes in positive framing condition, a significant feedback-related negativity (FRN) effect was elicited by outcomes in negative framing condition, even though the outcomes in different conditions were objectively equivalent. The results are explained in terms of the associative model of attribute framing effect which states that attribute framing effect occurs as a result of a valence-based associative processing. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  7. The Green Bank North Celestial Cap Pulsar Survey: New Pulsars and Future Prospects

    Science.gov (United States)

    Lynch, Ryan S.; Swiggum, Joe; Stovall, Kevin; Chawla, Pragya; DeCesar, Megan E.; Fonseca, Emmanuel; Levin, Lina; Cui, Bingyi; Kondratiev, Vlad; Archibald, Anne; Boyles, Jason; Hessels, Jason W. T.; Jenet, Fredrick; Kaplan, David; Karako-Argaman, Chen; Kaspi, Victoria; Martinez, Jose; McLaughlin, Maura; Ransom, Scott M.; Roberts, Mallory; Siemens, Xavier; Spiewak, Renee; Stairs, Ingrid; van Leeuwn, Joeri; Green Bank North Celestial Cap Survey Collaboration

    2018-01-01

    The Green Bank North Celestial Cap pulsar survey is the most successful low frequency pulsar survey ever. GBNCC uses the Green Bank telescope to cover the full visible sky at 350 MHz. With the survey over 70% complete, we have discovered over 150 pulsars, including 20 MSPs and 11 RRATs. I will report on the current status of the survey and plans for its completion in the coming years. I will also report on several discoveries including: timing solutions for dozens of new pulsars; new high precision MSPs and their suitability for inclusion in pulsar timing arrays; a new relativistic double neutron star system; new pulsar mass measurements; proper motion measurements for several MSPs; a new mode changing pulsar; interesting new MSP binaries; nulling fraction analyses; and possible implications of the lack of any fast radio bursts in the survey so far.

  8. Moon and other Celestial bodies: Debunking the Myth of Property Rights in Space

    Science.gov (United States)

    Sterns, P.; Tennen, L.

    The increasing role of the private sector in space creates virtually limitless opportunities. It is axiomatic that activities in space must be conducted in compliance with the applicable requirements of the corpus juris spatialis. Unfortunately, in their zeal to manufacture a profit, some proponents give insufficient consideration to the implications and ramifications of their ventures vis- a -vis the extant law of outer space, particularly in relation to the non-appropriation principle. Still other purveyors of proposals are more disingenuous, proffering elaborate yet analytically inadequate rationales to justify either abrogating or disregarding the legal framework applicable to activities in space, especially in regard to assertions of so called "property rights" in space, on the Moon, and on other celestial bodies. This article examines the fallacies of these propositions, and demonstrates that such claims of property rights are both unnecessary and counterproductive to the development of commercial space.

  9. A STUDY ON LOWER SECONDARY SCHOOL PUPILS’ PERCEPTIONS OF CERTAIN ASTRONOMICAL PHENOMENA AND CELESTIAL BODIES

    Directory of Open Access Journals (Sweden)

    VIRGINIA SASU

    2014-01-01

    Full Text Available The main purpose of this paper is to reveal certain misconceptions of astronomical phenomena and of celestial bodies that lower secondary school pupils have and which might represent an obstacle in the process of acquiring knowledge of astronomy, geography, and physics. We applied a questionnaire to a group of 26 pupils in the 6th grade at Colegiul Naţional Pedagogic „Gh. Lazăr” (“Gh. Lazăr National Pedagogical College in Cluj-Napoca, in the school year 2010 – 2011. The questionnaire consisted of six independent topics: the alternation of day and night, the seasons, the Moon, the solar system, the constellations and the speed of light. Pupils’ answers to these questions emphasize the importance of the study of astronomy as a school subject in order to facilitate building up appropriate mind constructs of the highest degree of objectivity about the world, about the environment we live in.

  10. Signature of the celestial spheres discovering order in the solar system

    CERN Document Server

    Warm, Harmut

    2010-01-01

    "A milestone in modern research on the the harmony of the spheres." - Novalis magazine "This book reignites the debate on the harmony of the spheres." - Das Goetheanum Is the solar system ordered, or is it simply the result of random and chaotic accidents? This book takes us on a powerful and compelling journey of discovery, revealing the celestial spheres' astonishingly complex patterns. The movements of the planets are found to correspond accurately with simple geometric figures and musical intervals, pointing to an exciting new perspective on the ancient idea of a "harmony of the spheres". Hartmut Warm's detailed presentation incorporates the distances, velocities and periods of conjunction of the planets, as well as the rotations of the Sun, Moon and Venus. Numerous graphics - including colour plates - illustrate the extraordinary beauty of the geometrical forms that result when the movements of several planets are viewed in relation to one another. In addition, the author describes and analyses the conce...

  11. VIOLENT FRAMES IN ACTION

    Energy Technology Data Exchange (ETDEWEB)

    Sanfilippo, Antonio P.; McGrath, Liam R.; Whitney, Paul D.

    2011-11-17

    We present a computational approach to radical rhetoric that leverages the co-expression of rhetoric and action features in discourse to identify violent intent. The approach combines text mining and machine learning techniques with insights from Frame Analysis and theories that explain the emergence of violence in terms of moral disengagement, the violation of sacred values and social isolation in order to build computational models that identify messages from terrorist sources and estimate their proximity to an attack. We discuss a specific application of this approach to a body of documents from and about radical and terrorist groups in the Middle East and present the results achieved.

  12. Continuous Shearlet Tight Frames

    KAUST Repository

    Grohs, Philipp

    2010-10-22

    Based on the shearlet transform we present a general construction of continuous tight frames for L2(ℝ2) from any sufficiently smooth function with anisotropic moments. This includes for example compactly supported systems, piecewise polynomial systems, or both. From our earlier results in Grohs (Technical report, KAUST, 2009) it follows that these systems enjoy the same desirable approximation properties for directional data as the previous bandlimited and very specific constructions due to Kutyniok and Labate (Trans. Am. Math. Soc. 361:2719-2754, 2009). We also show that the representation formulas we derive are in a sense optimal for the shearlet transform. © 2010 Springer Science+Business Media, LLC.

  13. New avenues for framing research

    NARCIS (Netherlands)

    de Vreese, C.H.

    2012-01-01

    In this article, the author reviews the studies in this special issue of the American Behavioral Scientist. It is a strong collection of articles reporting findings from an integrated project that looks at frame building, frames, and effects of frames. The project is part of an exciting large-scale

  14. Claims, Frames, and Blame

    Directory of Open Access Journals (Sweden)

    Bradley C. Freeman

    2017-01-01

    Full Text Available As economies in Southeast Asia develop, there is renewed interest in the impact such growth has on nature. This study seeks to investigate how environmental issues have been covered in the English-language press of the region. Are some countries providing greater print news coverage versus others? Are there detectable patterns or noticeable biases in the coverage? What sources are relied upon in the print media stories? And what frames do we see in the coverage? This study identified general coverage patterns of the environment over a 10-year period (2002-2012, in several of the region’s English-language newspapers. News stories were analyzed to discern the nature of the coverage, coding for several variables as indicated by previous literature. Results indicate that use of the term climate change became preferred over that of global warming. In addition, coverage increased greatly starting in 2006. Government officials were most often the sources quoted within stories (Claims. Articles contained more “judgments” about the issue than “solutions” (Frames. Finally, though most articles eschewed mentioning a specific actor as causing climate change, “man” was implicated in a number of stories more often than simply “nature” (Blame.

  15. Mapping in inertial frames

    International Nuclear Information System (INIS)

    Arunasalam, V.

    1989-05-01

    World space mapping in inertial frames is used to examine the Lorentz covariance of symmetry operations. It is found that the Galilean invariant concepts of simultaneity (S), parity (P), and time reversal symmetry (T) are not Lorentz covariant concepts for inertial observers. That is, just as the concept of simultaneity has no significance independent of the Lorentz inertial frame, likewise so are the concepts of parity and time reversal. However, the world parity (W) [i.e., the space-time reversal symmetry (P-T)] is a truly Lorentz covariant concept. Indeed, it is shown that only those mapping matrices M that commute with the Lorentz transformation matrix L (i.e., [M,L] = 0) are the ones that correspond to manifestly Lorentz covariant operations. This result is in accordance with the spirit of the world space Mach's principle. Since the Lorentz transformation is an orthogonal transformation while the Galilean transformation is not an orthogonal transformation, the formal relativistic space-time mapping theory used here does not have a corresponding non-relativistic counterpart. 12 refs

  16. Identifying issue frames in text.

    Directory of Open Access Journals (Sweden)

    Eyal Sagi

    Full Text Available Framing, the effect of context on cognitive processes, is a prominent topic of research in psychology and public opinion research. Research on framing has traditionally relied on controlled experiments and manually annotated document collections. In this paper we present a method that allows for quantifying the relative strengths of competing linguistic frames based on corpus analysis. This method requires little human intervention and can therefore be efficiently applied to large bodies of text. We demonstrate its effectiveness by tracking changes in the framing of terror over time and comparing the framing of abortion by Democrats and Republicans in the U.S.

  17. Frames of Reference in Mobile Augmented Reality Displays

    Science.gov (United States)

    Mou, Weimin; Biocca, Frank; Owen, Charles B.; Tang, Arthur; Xiao, Fan; Lim, Lynette

    2004-01-01

    In 3 experiments, the authors investigated spatial updating in augmented reality environments. Participants learned locations of virtual objects on the physical floor. They were turned to appropriate facing directions while blindfolded before making pointing judgments (e.g., "Imagine you are facing X. Point to Y"). Experiments manipulated the…

  18. Motor Extinction in Distinct Reference Frames: A Double Dissociation

    Directory of Open Access Journals (Sweden)

    Jennifer Heidler-Gary

    2013-01-01

    Full Text Available Objective: Test the hypothesis that right hemisphere stroke can cause extinction of left hand movements or movements of either hand held in left space, when both are used simultaneously, possibly depending on lesion site.

  19. Frame of Reference: Open Access Starts with You

    Science.gov (United States)

    Goetsch, Lori A.

    2010-01-01

    Federal legislation now requires the deposit of some taxpayer-funded research in "open-access" repositories--that is, sites where scholarship and research are made freely available over the Internet. The institutions whose faculty produce the research have begun to see the benefit of open-access publication as well. From the perspective of faculty…

  20. Experimental test of photonic entanglement in accelerated reference frames

    Science.gov (United States)

    Fink, Matthias; Rodriguez-Aramendia, Ana; Handsteiner, Johannes; Ziarkash, Abdul; Steinlechner, Fabian; Scheidl, Thomas; Fuentes, Ivette; Pienaar, Jacques; Ralph, Timothy C.; Ursin, Rupert

    2017-05-01

    The unification of the theory of relativity and quantum mechanics is a long-standing challenge in contemporary physics. Experimental techniques in quantum optics have only recently reached the maturity required for the investigation of quantum systems under the influence of non-inertial motion, such as being held at rest in gravitational fields, or subjected to uniform accelerations. Here, we report on experiments in which a genuine quantum state of an entangled photon pair is exposed to a series of different accelerations. We measure an entanglement witness for g-values ranging from 30 mg to up to 30 g--under free-fall as well on a spinning centrifuge--and have thus derived an upper bound on the effects of uniform acceleration on photonic entanglement.

  1. Childhood PTSD in Israel: A Cross Cultural Frame of Reference.

    Science.gov (United States)

    Milgram, Noach Norman

    There is considerable awareness among Israeli mental health workers and citizens of the importance of differentiating between acute or chronic reactions to severely stressful life situations and manifestations of mental illness and anxiety, or developmental and adjustment disorders. Israeli mental health workers have become expert and are heavily…

  2. The role of perceptual reference frames in visual field asymmetries.

    Science.gov (United States)

    Robertson, L C; Lamb, M R

    1988-01-01

    The direct access model of hemispheric asymmetry was tested in a letter reflection (normal of reflected) judgement task. In the baseline condition letters were presented in their upright orientation, and reaction times were faster to letters presented in the right visual field than to those presented in the left visual field. In two other conditions the slides, and thus the letters, were rotated +90 degrees clockwise (Rotated +90) from upright or -90 degrees counterclockwise (Rotated -90). This resulted in the letters in both rotated conditions being shown in the upper or lower visual field through the sagittal plane but rotated 90 degrees. Despite this fact a "right field" advantage was again found when the right field was defined relative to the orientation of the tops of the rotated letters (lower visual field in the Rotated +90 condition and upper visual field in the Rotated -90 condition). These results demonstrate that the internal representation of locations in space is more important in predicting visual field asymmetries, at least in the present task, than the field of stimulus presentation relative to the fovea.

  3. Frames of References – Art Museums as Unique Visual Media

    Directory of Open Access Journals (Sweden)

    Aneta Hristova

    2015-10-01

    Full Text Available The age old activity of collecting arts is not intrinsically dependent on the art museum as separate architectural type. How was the art museum as an independent structure conceptualized and why? What was the idea behind that concept? Was it created as a medium consciously and what kind of messages was it supposed to deliver? What kind of unique “textual” overlaps the various disciplines of archaeology, art history, politics, literature, science and architecture created in order to produce what we today recognize as art museum space? This study focuses on the crucial historical moments of the late 17th century when such questions were posed for the first time within the classical discourse of the French architectural theory which followed the consolidation of French absolutism and the foundation of the Royal academies of arts and sciences, until the mid 19th century when the answers to those questions were finally exemplified in built architecture. The study gives a comprehensive overview of the cultural context art museums as public institutions emerged from and became new spatial models for collective cultivation.

  4. Versions and perversions of rigid frames: The bucking importance in the beams design of industrial warehouses

    International Nuclear Information System (INIS)

    Guerra Romero, I.; Fernandez Majo, M. C.; Valdes, A. J.

    2010-01-01

    In this paper many bibliographic references have been analyses which deal on the importance of the buckling in rigid frames, and many versions of it, have been got. About 70 frames have been analysed by the authors and they have found that it is advisable to consider the bucking in the design of frames beams. (Author) 30 refs.

  5. Behaviour of Strengthened RC Frames with Eccentric Steel Braced Frames

    Directory of Open Access Journals (Sweden)

    Kamanli Mehmet

    2017-01-01

    Full Text Available After devastating earthquakes in recent years, strengthening of reinforced concrete buildings became an important research topic. Reinforced concrete buildings can be strengthened by steel braced frames. These steel braced frames may be made of concentrically or eccentrically indicated in Turkish Earthquake Code 2007. In this study pushover analysis of the 1/3 scaled 1 reinforced concrete frame and 1/3 scaled 4 strengthened reinforced concrete frames with internal eccentric steel braced frames were conducted by SAP2000 program. According to the results of the analyses conducted, load-displacement curves of the specimens were compared and evaluated. Adding eccentric steel braces to the bare frame decreased the story drift, and significantly increased strength, stiffness and energy dissipation capacity. In this strengthening method lateral load carrying capacity, stiffness and dissipated energy of the structure can be increased.

  6. Behaviour of Strengthened RC Frames with Eccentric Steel Braced Frames

    Science.gov (United States)

    Kamanli, Mehmet; Unal, Alptug

    2017-10-01

    After devastating earthquakes in recent years, strengthening of reinforced concrete buildings became an important research topic. Reinforced concrete buildings can be strengthened by steel braced frames. These steel braced frames may be made of concentrically or eccentrically indicated in Turkish Earthquake Code 2007. In this study pushover analysis of the 1/3 scaled 1 reinforced concrete frame and 1/3 scaled 4 strengthened reinforced concrete frames with internal eccentric steel braced frames were conducted by SAP2000 program. According to the results of the analyses conducted, load-displacement curves of the specimens were compared and evaluated. Adding eccentric steel braces to the bare frame decreased the story drift, and significantly increased strength, stiffness and energy dissipation capacity. In this strengthening method lateral load carrying capacity, stiffness and dissipated energy of the structure can be increased.

  7. Riesz frames and approximation of the frame coefficients

    DEFF Research Database (Denmark)

    Casazza, P.; Christensen, Ole

    1998-01-01

    A frame is a fmaily {f i } i=1 ∞ of elements in a Hilbert space with the property that every element in can be written as a (infinite) linear combination of the frame elements. Frame theory describes how one can choose the corresponding coefficients, which are called frame coefficients. From...... the mathematical point of view this is gratifying, but for applications it is a problem that the calculation requires inversion of an operator on . The projection method is introduced in order to avoid this problem. The basic idea is to consider finite subfamilies {f i } i=1 n of the frame and the orthogonal...... projection Pn onto its span. For has a representation as a linear combination of fi, i=1,2,..., n and the corresponding coefficients can be calculated using finite dimensional methods. We find conditions implying that those coefficients converge to the correct frame coefficients as n→∞, in which case we have...

  8. Fusion frames and G-frames in Banach spaces

    Indian Academy of Sciences (India)

    Amir Khosravi and Behrooz Khosravi. DEFINITION 1.2. Let X be a Banach space with dual space X. ∗ and Xd be a BK-space. A countable family. {gi } in X. ∗ is called an Xd-frame ... In §2 we study g-frames in Banach spaces and in §3 we study fusion frames in Banach spaces. ..... Soc., Providence, RI) (1999). [4] Casazza ...

  9. Frames, agency and institutional change

    DEFF Research Database (Denmark)

    Rasmussen, Grane Mikael Gregaard; Jensen, Per Langaa; Gottlieb, Stefan Christoffer

    2017-01-01

    This study examines change and the sources influencing the formulation and diffusion of policies in construction. The change examined is the introduction of a benchmarking policy initiative in the Danish construction industry. Using institutional theory with emphasis on the concepts of frames...... and framings, we show how strategically motivated actors are able to frame policy problems in ways that disclose the mixture of motives, interests and institutional mechanisms at play in change processes. In doing so, we contribute to the literature on the role of agency in institutional change and the framing...

  10. Pairs of dual periodic frames

    DEFF Research Database (Denmark)

    Christensen, Ole; Goh, Say Song

    2012-01-01

    The time–frequency analysis of a signal is often performed via a series expansion arising from well-localized building blocks. Typically, the building blocks are based on frames having either Gabor or wavelet structure. In order to calculate the coefficients in the series expansion, a dual frame...... is needed. The purpose of the present paper is to provide constructions of dual pairs of frames in the setting of the Hilbert space of periodic functions L2(0,2π). The frames constructed are given explicitly as trigonometric polynomials, which allows for an efficient calculation of the coefficients...

  11. Basal electric and magnetic fields of celestial bodies come from positive-negative charge separation caused by gravitation of quasi-Casimir pressure in weak interaction

    Science.gov (United States)

    Chen, Shao-Guang

    basal electric and magnetic fields of celestial bodies will affect directly all fields referring to the electromagnetic characteristics in space science, e.g., it predict that the spin speed of the sunspot is in direct proportion to its magnetic moment.

  12. Power to the frame: bringing sociology back to frame analysis

    NARCIS (Netherlands)

    Vliegenthart, R.; van Zoonen, L.

    2011-01-01

    This article critically reviews current frame and framing research in media and communication studies. It is first argued that most authors fail to distinguish between ‘frame’ and ‘framing’ and therewith produce a conceptual confusion and imprecision that is not conducive to the field. Second, it is

  13. Value Framing: A Prelude to Software Problem Framing

    NARCIS (Netherlands)

    Wieringa, Roelf J.; Gordijn, Jaap; van Eck, Pascal; Cox, K.; Hall, J.G.; Rapanotti, L.

    2004-01-01

    Software problem framing is a way to find specifications for software. Software problem frames can be used to structure the environment of a software system (the machine) and specify desired software properties in such a way that we can show that software with these properties will help achieve the

  14. New characterizations of fusion frames (frames of subspaces)

    Indian Academy of Sciences (India)

    Theory (College Park, MD, 2003) Contemp. Math. 345, Amer. Math. Soc. (RI: Provi- dence) (2004) 87–113. [4] Casazza P G and Kutyniok G, Robustness of Fusion Frames under Erasures of sub- spaces and of Local Frame Vectors, Radon transforms, geometry, and wavelets (LA: New Orleans) (2006) Contemp. Math., Amer.

  15. Searching for Axions from Celestial Objects with the X-Ray Telescope at CAST

    CERN Document Server

    Guthörl, T

    2009-01-01

    The CAST (CERN Solar Axion Telescope) experiment is designed to detect axions from the sun by making use of the inverse Primakoff effekt i.e. reconversion of axions into X-ray photons under the influence of a strong magnetic field. In order to track the sun the magnet used is mounted to a moveable device. This movability can also be used to track celestial objects of interest such as the galactic centre or Scorpio X-1, which is the brightest X-ray source besides the sun. The data gained with the CCD detector during trackings of these objects are analysed in this work. Since no signal above background can be observed an upper limit on the free parameter flux times axion-photon coupling constant^2 is determined. This upper limit in turn can be used to calculate a maximum energy loss due to axion emission for both the galactic centre and Sco X-1. The results presented in this work imply that e.g. the galactic centre can emit axions with up to 10^42 W without being detected by CAST.

  16. AstrodyToolsWeb an e-Science project in Astrodynamics and Celestial Mechanics fields

    Science.gov (United States)

    López, R.; San-Juan, J. F.

    2013-05-01

    Astrodynamics Web Tools, AstrodyToolsWeb (http://tastrody.unirioja.es), is an ongoing collaborative Web Tools computing infrastructure project which has been specially designed to support scientific computation. AstrodyToolsWeb provides project collaborators with all the technical and human facilities in order to wrap, manage, and use specialized noncommercial software tools in Astrodynamics and Celestial Mechanics fields, with the aim of optimizing the use of resources, both human and material. However, this project is open to collaboration from the whole scientific community in order to create a library of useful tools and their corresponding theoretical backgrounds. AstrodyToolsWeb offers a user-friendly web interface in order to choose applications, introduce data, and select appropriate constraints in an intuitive and easy way for the user. After that, the application is executed in real time, whenever possible; then the critical information about program behavior (errors and logs) and output, including the postprocessing and interpretation of its results (graphical representation of data, statistical analysis or whatever manipulation therein), are shown via the same web interface or can be downloaded to the user's computer.

  17. Dual-EKF-Based Real-Time Celestial Navigation for Lunar Rover

    Directory of Open Access Journals (Sweden)

    Li Xie

    2012-01-01

    Full Text Available A key requirement of lunar rover autonomous navigation is to acquire state information accurately in real-time during its motion and set up a gradual parameter-based nonlinear kinematics model for the rover. In this paper, we propose a dual-extended-Kalman-filter- (dual-EKF- based real-time celestial navigation (RCN method. The proposed method considers the rover position and velocity on the lunar surface as the system parameters and establishes a constant velocity (CV model. In addition, the attitude quaternion is considered as the system state, and the quaternion differential equation is established as the state equation, which incorporates the output of angular rate gyroscope. Therefore, the measurement equation can be established with sun direction vector from the sun sensor and speed observation from the speedometer. The gyro continuous output ensures the algorithm real-time operation. Finally, we use the dual-EKF method to solve the system equations. Simulation results show that the proposed method can acquire the rover position and heading information in real time and greatly improve the navigation accuracy. Our method overcomes the disadvantage of the cumulative error in inertial navigation.

  18. Recombination of radiation defects in solid methane: neutron sources and cryo-volcanism on celestial bodies

    Science.gov (United States)

    Kirichek, O.; Savchenko, E. V.; Lawson, C. R.; Khyzhniy, I. V.; Jenkins, D. M.; Uyutnov, S. A.; Bludov, M. A.; Haynes, D. J.

    2018-03-01

    Physicochemical properties of solid methane exposed to ionizing radiation have attracted significant interest in recent years. Here we present new trends in the study of radiation effects in solid methane. We particularly focus on relaxation phenomena in solid methane pre-irradiated by energetic neutrons and electron beam. We compare experimental results obtained in the temperature range from 10K to 100K with a model based on the assumption that radiolysis defect recombinations happen in two stages, at two different temperatures. In the case of slow heating up of the solid methane sample, irradiated at 10K, the first wave of recombination occurs around 20K with a further second wave taking place between 50 and 60K. We also discuss the role of the recombination mechanisms in “burp” phenomenon discovered by J. Carpenter in the late 1980s. An understanding of these mechanisms is vital for the designing and operation of solid methane moderators used in advanced neutron sources and could also be a possible explanation for the driving forces behind cryo-volcanism on celestial bodies.

  19. Periodic, Quasi-Periodic and Chaotic Motions in Celestial Mechanics: Theory and Applications Selected papers from the Fourth Meeting on Celestial Mechanics, CELMEC IV San Martino al Cimino (Italy), 11–16 September 2005

    CERN Document Server

    Celletti, A

    2006-01-01

    The book provides the most recent advances of Celestial Mechanics, as provided by high-level scientists working in this field. It covers theoretical investigations as well as applications to concrete problems. Outstanding review papers are included in the book and they introduce the reader to leading subjects, like the variational approaches to find periodic orbits, the stability theory of the N-body problem, the spin-orbit resonances and chaotic dynamics, the space debris polluting the circumterrestrial space.

  20. FRAME CATAGORIZATION OF CONVERSATIONAL INTIMACY

    OpenAIRE

    Lyubov Kit

    2017-01-01

    The article deals with the notion of intimacy. The frame of intimacy is studied on the basis of the linguistic parameters, analysis of text extracts and universal knowledge about intimacy. Frame analysis helped to establish the catagorization of types and nominators of intimate speech genres, their construction in static and dynamic aspects.

  1. Frame Catagorization of Conversational Intimacy

    OpenAIRE

    Lyubov Kit

    2017-01-01

    The article deals with the notion of intimacy. The frame of intimacy is studied on the basis of the linguistic parameters, analysis of text extracts and universal knowledge about intimacy. Frame analysis helped to establish the catagorization of types and nominators of intimate speech genres, their construction in static and dynamic aspects.

  2. On Definition of Skew Frames

    Science.gov (United States)

    Kruml, David

    2010-12-01

    Skew frames represent a common generalization of frames and orthomodular lattices. They could serve as Lindenbaum algebras of quantum intuitionistic logic as well as invariants of noncommutative C*-algebras. It is shown that lattices of open projections with skew (partial) operations are complete invariants of C*-algebras and that these operations are preserved by morphims of C*-algebras.

  3. Effects of News Frames on Perceived Risk, Emotions, and Learning

    Science.gov (United States)

    Otieno, Christine; Spada, Hans; Renkl, Alexander

    2013-01-01

    The media play a key role in forming opinions by influencing people´s understanding and perception of a topic. People gather information about topics of interest from the internet and print media, which employ various news frames to attract attention. One example of a common news frame is the human-interest frame, which emotionalizes and dramatizes information and often accentuates individual affectedness. Our study investigated effects of human-interest frames compared to a neutral-text condition with respect to perceived risk, emotions, and knowledge acquisition, and tested whether these effects can be "generalized" to common variants of the human-interest frame. Ninety-one participants read either one variant of the human-interest frame or a neutrally formulated version of a newspaper article describing the effects of invasive species in general and the Asian ladybug (an invasive species) in particular. The framing was achieved by varying the opening and concluding paragraphs (about invasive species), as well as the headline. The core text (about the Asian ladybug) was the same across all conditions. All outcome variables on framing effects referred to this common core text. We found that all versions of the human-interest frame increased perceived risk and the strength of negative emotions compared to the neutral text. Furthermore, participants in the human-interest frame condition displayed better (quantitative) learning outcomes but also biased knowledge, highlighting a potential dilemma: Human-interest frames may increase learning, but they also lead to a rather unbalanced view of the given topic on a “deeper level”. PMID:24223999

  4. Effects of news frames on perceived risk, emotions, and learning.

    Directory of Open Access Journals (Sweden)

    Christine Otieno

    Full Text Available The media play a key role in forming opinions by influencing people´s understanding and perception of a topic. People gather information about topics of interest from the internet and print media, which employ various news frames to attract attention. One example of a common news frame is the human-interest frame, which emotionalizes and dramatizes information and often accentuates individual affectedness. Our study investigated effects of human-interest frames compared to a neutral-text condition with respect to perceived risk, emotions, and knowledge acquisition, and tested whether these effects can be "generalized" to common variants of the human-interest frame. Ninety-one participants read either one variant of the human-interest frame or a neutrally formulated version of a newspaper article describing the effects of invasive species in general and the Asian ladybug (an invasive species in particular. The framing was achieved by varying the opening and concluding paragraphs (about invasive species, as well as the headline. The core text (about the Asian ladybug was the same across all conditions. All outcome variables on framing effects referred to this common core text. We found that all versions of the human-interest frame increased perceived risk and the strength of negative emotions compared to the neutral text. Furthermore, participants in the human-interest frame condition displayed better (quantitative learning outcomes but also biased knowledge, highlighting a potential dilemma: Human-interest frames may increase learning, but they also lead to a rather unbalanced view of the given topic on a "deeper level".

  5. Conference on Hamiltonian Systems and Celestial Mechanics 2014 & Workshop on Virus Dynamics and Evolution : Extended Abstracts Spring 2014

    CERN Document Server

    Cors, Josep; Llibre, Jaume; Korobeinikov, Andrei

    2015-01-01

    The two parts of the present volume contain extended conference abstracts corresponding to selected talks given by participants at the "Conference on Hamiltonian Systems and Celestial Mechanics 2014" (HAMSYS2014) (15 abstracts) and at the "Workshop on Virus Dynamics and Evolution" (12 abstracts), both held at the Centre de Recerca Matemàtica (CRM) in Barcelona from June 2nd to 6th, 2014, and from June 23th to 27th, 2014, respectively. Most of them are brief articles, containing preliminary presentations of new results not yet published in regular research journals. The articles are the result of a direct collaboration between active researchers in the area after working in a dynamic and productive atmosphere. The first part is about Central Configurations, Periodic Orbits and Hamiltonian Systems with applications to Celestial Mechanics – a very modern and active field of research. The second part is dedicated to mathematical methods applied to viral dynamics and evolution. Mathematical modelling of biologi...

  6. History of Space-Based Infrared Astronomy and the Air Force Infrared Celestial Backgrounds Program

    Science.gov (United States)

    2008-04-18

    1962a, 1986) described the pains that Rosse took in making his observations as accurate as possible. Rosse isolated the thermal emission by observing...so the six apparitions appear at different in-scan and cross-scan positions on a pixel. Figure 103 compares the single frame image on the left with

  7. Further adventures of the celestial sleuth using astronomy to solve more mysteries in art, history, and literature

    CERN Document Server

    Olson, Donald W

    2018-01-01

    From the author of "Celestial Sleuth" (2014), yet more mysteries in art, history, and literature are solved by calculating phases of the Moon, determining the positions of the planets and stars, and identifying celestial objects in paintings. In addition to helping to crack difficult cases, these studies spark our imagination and provide a better understanding of the skies. Weather archives, vintage maps, tides, historical letters and diaries, military records and the assistance of experts in related fields help with this work. For each historical event influenced by astronomy, there is a different kind of mystery to be solved. How did the changing tides affect an army's battle plans? How did the phases of the moon affect how an artist painted a landscape? Follow these exciting investigations with a master “celestial sleuth” as he tracks down the truth and helps unravel mysteries as far back as the Middle Ages and as recent as the iconic 1945 photograph of a kiss in Times Square on VJ Day. Topics or "case...

  8. Quotation and Framing

    DEFF Research Database (Denmark)

    Petersen, Nils Holger

    2010-01-01

    far beyond the traditional, thus creating a framework of extreme contrasts. The paper will contextualize, analyze and interpret Black Angels – which the composer explicitly linked to the Vietnam War – in a broad context of music, intermediality, religious symbolism, and cultural memory, pointing......The purpose of this article is to discuss Crumb’s musical and intermedial intertextuality mainly through his Black Angels: Thirteen Images from the Dark Land for Electric String Quartet (1970), as an individually original but also representative compositional practice for the twentieth century....... As in other compositions, George Crumb has integrated musical quotations and various musical styles in Black Angels, including a web of references which extend into other media, in such a way that they form an indispensable part of the basic construction of the work: these components form part of its newness...

  9. On the Analysis of Multistep-Out-of-Grid Method for Celestial Mechanics Tasks

    Science.gov (United States)

    Olifer, L.; Choliy, V.

    2016-09-01

    Occasionally, there is a necessity in high-accurate prediction of celestial body trajectory. The most common way to do that is to solve Kepler's equation analytically or to use Runge-Kutta or Adams integrators to solve equation of motion numerically. For low-orbit satellites, there is a critical need in accounting geopotential and another forces which influence motion. As the result, the right side of equation of motion becomes much bigger, and classical integrators will not be quite effective. On the other hand, there is a multistep-out-of-grid (MOG) method which combines Runge-Kutta and Adams methods. The MOG method is based on using m on-grid values of the solution and n × m off-grid derivative estimations. Such method could provide stable integrators of maximum possible order, O (hm+mn+n-1). The main subject of this research was to implement and analyze the MOG method for solving satellite equation of motion with taking into account Earth geopotential model (ex. EGM2008 (Pavlis at al., 2008)) and with possibility to add other perturbations such as atmospheric drag or solar radiation pressure. Simulations were made for satellites on low orbit and with various eccentricities (from 0.1 to 0.9). Results of the MOG integrator were compared with results of Runge-Kutta and Adams integrators. It was shown that the MOG method has better accuracy than classical ones of the same order and less right-hand value estimations when is working on high orders. That gives it some advantage over "classical" methods.

  10. The Inner Meaning of Outer Space:Human Nature and the Celestial Realm

    Directory of Open Access Journals (Sweden)

    Timothy L. Hubbard

    2009-11-01

    Full Text Available Kant afirmaba que los seres humanos poseen un conocimiento a priori del espacio. Aunque este argumento se centra en la física de los cuerpos, también tiene implicaciones para la psicología del ser. Muchas culturas humanas organizan las estrellas en constelaciones (imponen estructura; atribuyen propiedades, conductas y habilidades a objetos en el reino celeste (esto es, determinan significado; y usan la regularidad percibida en los reinos celestes para el desarrollo de calendarios, navegaciones de grandes distancias, agricultura y astrología (buscan predicción y control. La inaccesibilidad física del reino celeste permite una potente fuente de metáforas, así como la protección de los mitos sobre el origen y la ascensión, los lugares del poder y aquellos donde habitan dioses, seres inmortales y otras almas. Los desarrollos en astronomía y cosmología influyeron las opiniones sobre la naturaleza humana y el lugar de la humanidad en el universo; estos cambios ponen en paralelo los descensos en el egocentrismo y el desarrollo humano. Las visiones acerca de los presuntos seres (como los ángeles y los extraterrestres del reino celestial (y cómo comunicarse con esos seres son antropocéntricas e ignoran factores evolutivos del desarrollo físico y cognitivo. Se sugiere que al considerar opiniones y usos del reino celeste, aprendemos no sólo acerca del universo, sino también sobre nosotros mismos.

  11. Go Dark Charleston 2017: Preparing the Lowcountry of Charleston, SC for a Unique Celestial Event

    Science.gov (United States)

    Hall, C.; Runyon, C. R.; Royle, M. L.

    2017-12-01

    The August 2017 total solar eclipse will cross the United States, from Oregon to South Carolina, for the first time in almost 100 years. This awe-inspiring event occurs when the moon crosses between the Sun and the Earth, casting a shadow on Earth. Charleston, SC is the final point in this path before the eclipse heads offshore. As such, it provides an opportunity for Charlestonians to witness the grand finale of such an extraordinary celestial event. In collaboration, the Lowcountry Hall of Science and Math (LHSM) and the SC NASA Space Grant Consortium (SCSG) are working with entities across the state to help raise awareness among the general public to the uniqueness of this total solar eclipse. The team is delivering content-rich, hands-on professional development statewide to formal and informal educators, park rangers and city/county government personnel to ensure an understanding behind why we have eclipses as well as safety when viewing eclipses. Our team is working with community organizations, such as sports teams (i.e., Charleston Riverdogs Baseball, Charleston Battery Soccer), museums, aquariums, state and national parks, etc. to bring NASA scientists, engineers and educators together to deliver exciting community demonstrations before, during and after the day of the eclipse. The LHSM, working directly with the Aquarium and Charlestowne Landing State Park, are capturing animal behavior, specifically marine birds and wolves, during the eclipse. In addition, the team is working directly with College of Charleston undergraduates and two local high schools to launch high-altitude balloons to capture video and pictures, as well as, perform science experiments focusing on the eclipse. And finally, the LHSM through SCSG funding, is determining and documenting the extent of knowledge and cultural misconceptions surrounding solar eclipses within the greater Charleston community. In our session, the team will share the outcomes of these varied endeavors.

  12. Integration of celestial compass cues in the central complex of the locust brain.

    Science.gov (United States)

    Pegel, Uta; Pfeiffer, Keram; Homberg, Uwe

    2018-01-29

    Many insects rely on celestial compass cues such as the polarization pattern of the sky for spatial orientation. In the desert locust, the central complex (CX) houses multiple sets of neurons, sensitive to the oscillation plane of polarized light and thus probably acts as an internal polarization compass. We investigated whether other sky compass cues like direct sunlight or the chromatic gradient of the sky might contribute to this compass. We recorded from polarization-sensitive CX neurons while an unpolarized green or ultraviolet light spot was moved around the head of the animal. All types of neuron that were sensitive to the plane of polarization ( E -vector) above the animal also responded to the unpolarized light spots in an azimuth-dependent way. The tuning to the unpolarized light spots was independent of wavelength, suggesting that the neurons encode solar azimuth based on direct sunlight and not on the sky chromatic gradient. Two cell types represented the natural 90 deg relationship between solar azimuth and zenithal E -vector orientation, providing evidence to suggest that solar azimuth information supports the internal polarization compass. Most neurons showed advances in their tuning to the E -vector and the unpolarized light spots dependent on rotation direction, consistent with anticipatory signaling. The amplitude of responses and its variability were dependent on the level of background firing, possibly indicating different internal states. The integration of polarization and solar azimuth information strongly suggests that besides the polarization pattern of the sky, direct sunlight might be an important cue for sky compass navigation in the locust. © 2018. Published by The Company of Biologists Ltd.

  13. Serialising languages: Satellite-framed, verb-framed or neither ...

    African Journals Online (AJOL)

    The diversity in the coding of the core schema of motion, i.e., Path, has led to a traditional typology of languages into verb-framed and satellite-framed languages. In the former Path is encoded in verbs and in the latter it is encoded in non-verb elements that function as sisters to co-event expressing verbs such as manner ...

  14. Frames and counter-frames giving meaning to dementia: a framing analysis of media content.

    Science.gov (United States)

    Van Gorp, Baldwin; Vercruysse, Tom

    2012-04-01

    Media tend to reinforce the stigmatization of dementia as one of the most dreaded diseases in western society, which may have repercussions on the quality of life of those with the illness. The persons with dementia, but also those around them become imbued with the idea that life comes to an end as soon as the diagnosis is pronounced. The aim of this paper is to understand the dominant images related to dementia by means of an inductive framing analysis. The sample is composed of newspaper articles from six Belgian newspapers (2008-2010) and a convenience sample of popular images of the condition in movies, documentaries, literature and health care communications. The results demonstrate that the most dominant frame postulates that a human being is composed of two distinct parts: a material body and an immaterial mind. If this frame is used, the person with dementia ends up with no identity, which is in opposition to the Western ideals of personal self-fulfilment and individualism. For each dominant frame an alternative counter-frame is defined. It is concluded that the relative absence of counter-frames confirms the negative image of dementia. The inventory might be a help for caregivers and other professionals who want to evaluate their communication strategy. It is discussed that a more resolute use of counter-frames in communication about dementia might mitigate the stigma that surrounds dementia. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Putting Safety in the Frame

    Directory of Open Access Journals (Sweden)

    Valerie Jean O’Keeffe

    2015-06-01

    Full Text Available Current patient safety policy focuses nursing on patient care goals, often overriding nurses’ safety. Without understanding how nurses construct work health and safety (WHS, patient and nurse safety cannot be reconciled. Using ethnography, we examine social contexts of safety, studying 72 nurses across five Australian hospitals making decisions during patient encounters. In enacting safe practice, nurses used “frames” built from their contextual experiences to guide their behavior. Frames are produced by nurses, and they structure how nurses make sense of their work. Using thematic analysis, we identify four frames that inform nurses’ decisions about WHS: (a communicating builds knowledge, (b experiencing situations guides decisions, (c adapting procedures streamlines work, and (d team working promotes safe working. Nurses’ frames question current policy and practice by challenging how nurses’ safety is positioned relative to patient safety. Recognizing these frames can assist the design and implementation of effective WHS management.

  16. Analysis of frame structure of medium and small truck crane

    Science.gov (United States)

    Cao, Fuyi; Li, Jinlong; Cui, Mengkai

    2018-03-01

    Truck crane is an important part of hoisting machinery. Frame, as the support component of the quality of truck crane, determines the safety of crane jib load and the rationality of structural design. In this paper, the truck crane frame is a box structure, the three-dimensional model is established in CATIA software, and imported into Hyperworks software for finite element analysis. On the base of doing constraints and loads for the finite element model of the frame, the finite element static analysis is carried out. And the static stress test verifies whether the finite element model and the frame structure design are reasonable; then the free modal analysis of the frame and the analysis of the first 8 - order modal vibration deformation are carried out. The analysis results show that the maximum stress value of the frame is greater than the yield limit value of the material, and the low-order modal value is close to the excitation frequency value, which needs to be improved to provide theoretical reference for the structural design of the truck crane frame.

  17. Optimization of position of geometrical frame by SNV

    Science.gov (United States)

    Chen, Long-De; Zhao, Fu-Ling; Li, Man

    1993-09-01

    The geometrical frame moves in different directions and areas when its tolerance zones and (or) location dimensions are determined in defferent ways. In this paper, by means of the measured coordinate values of the toleranced features, vectors are used to study the translations and (or) rotations of the geometrical frame, and further to judge if the errors are minimum and up to standard when the constraining conditions are satisfied. The diameter of the minimum envelope circle of error is the value of the error being searched. During translation and (or) rotation of the geometrical frame, if there are any the same name vectors (SNV for short) on the envelope circle of error which envelops the measured elements, or, in spite of SNVs , the envelope circle of error cannot be further reduced because of the constraint of the reference, such an envelope circle of error is called the minimum one. The results obtained show that 1 . the minimum envelope circle of position error can be found using SNV technique; 2. on the circle there may be 4, 3, 2 even just 1 point because of the constraint of the reference; 3 . the SNV technique can describe the change of the geometrical frame visually and is convenient for on-the-spot technological analysis; 4. whether the geometrical frame has compensation of reference or not, the position errors can be evaluated; 5. this technique is suitable for judging the measured results of a hole group distributed on a rectangle or a circumference.

  18. Intrinsic nonlinearity and method of disturbed observations in inverse problems of celestial mechanics

    Science.gov (United States)

    Avdyushev, Victor A.

    2017-12-01

    Orbit determination from a small sample of observations over a very short observed orbital arc is a strongly nonlinear inverse problem. In such problems an evaluation of orbital uncertainty due to random observation errors is greatly complicated, since linear estimations conventionally used are no longer acceptable for describing the uncertainty even as a rough approximation. Nevertheless, if an inverse problem is weakly intrinsically nonlinear, then one can resort to the so-called method of disturbed observations (aka observational Monte Carlo). Previously, we showed that the weaker the intrinsic nonlinearity, the more efficient the method, i.e. the more accurate it enables one to simulate stochastically the orbital uncertainty, while it is strictly exact only when the problem is intrinsically linear. However, as we ascertained experimentally, its efficiency was found to be higher than that of other stochastic methods widely applied in practice. In the present paper we investigate the intrinsic nonlinearity in complicated inverse problems of Celestial Mechanics when orbits are determined from little informative samples of observations, which typically occurs for recently discovered asteroids. To inquire into the question, we introduce an index of intrinsic nonlinearity. In asteroid problems it evinces that the intrinsic nonlinearity can be strong enough to affect appreciably probabilistic estimates, especially at the very short observed orbital arcs that the asteroids travel on for about a hundredth of their orbital periods and less. As it is known from regression analysis, the source of intrinsic nonlinearity is the nonflatness of the estimation subspace specified by a dynamical model in the observation space. Our numerical results indicate that when determining asteroid orbits it is actually very slight. However, in the parametric space the effect of intrinsic nonlinearity is exaggerated mainly by the ill-conditioning of the inverse problem. Even so, as for the

  19. Mechanisms of Earth activity forsed by external celestial bodies:energy budjet and nature of cyclicity

    Science.gov (United States)

    Barkin, Yu. V.; Ferrandiz, J. M.

    2003-04-01

    In given report we discuss tidal and non-tidal mechanisms of forced tectonic (endogenous) activity of the Earth caused by gravitational attraction of the Moon, Sun and the planets. On the base of the classical solution of the problem of elasticity for model of the Earth with concentric mass distribution the evaluations of the tidal energy and power of Earth lunar-solar deformations, including their joint effect, were obtained. Important role of the joint energetic effect of rotational deformation of the Earth with lunar and solar tides was illustrated. Gravitational interaction of the Moon and Sun with non-spherical, non-homogeneous shells of the Earth generates big additional mechanical forces and moments of the interaction of the neighboring shells (rigid core, liquid core, mantle, lithosphere and separate plates). Acting of these forces and moments in the different time scales on the corresponding sells generates cyclic perturbations of the tensional state of the shells, their deformations, small relative translational displacements and small relative rotational oscillations of the shells. In geological period of time it leads to a fundamental tectonic reconstruction of the Earth. These additional forces and moments of the cyclic celestial-mechanical nature produce cyclic deformations of the all layers of the body and organize and control practically all natural processes. The additional force between mantle and core is cyclic and characterized by the wide basis of frequencies typical for orbital motions (of the Sun, Moon and planets), for rotational motion of the Earth, Moon and Sun and for many from observed natural processes. The problem about small relative translatory-rotary motion of the two shells separated by the thin viscous-elastic layer is studied. The differential equations of motion were obtained and have been studied in particular cases (plane motion of system; case of two axisymmetrical interacting shells and oth.) by approximate methods of small

  20. The spaces in the looking glass: stilling the frame/framing the still

    Directory of Open Access Journals (Sweden)

    Marvin E. Kirsh

    2015-06-01

    Full Text Available The purpose of this writing is to propose a frame of view, a form as the eternal world element, that is compatible with paradox within the history of ideas, modern discovery as they confront one another. Under special consideration are problems of representation of phenomena, life, the cosmos as the rational facility of mind confronts the physical/perceptual, and itself. Current topics in pursuit are near as diverse and numbered as are the possibilities for a world composed strictly of uniqueness able to fill infinite space; it is assumed that not all of the paths chosen in contemporary pursuits will produce coherent determinations in an appropriate frame able to accommodate a world of nominals in motion, containing motion, and is commensurate with basic physical law and the propagation of form, change from within. Intended as a potential guiding post for the aim of reason seeking to select, define and capture topics, chosen as special examples are the works of logistician/mathematician Lewis Carroll as he presents a paradox of actuality verses the reality of perception in Alice in Wonderland, the theory of relativity of Albert Einstein as he fails to elaborate a mathematics to communicate an inertial frame of reference, and the reconstruction ideas of Jacques Derrida as he refers for contrast with the scientific world view constructed of dualisms, monisms that are conceived to have no opposites. Supporting discussion is evolved from the works of Bertrand Russell, Erwin Schrodinger, Jurgen Habermas, Bronislaw Malinowski, Michel Foucault.

  1. GEOdetic Data assimilation and EStimation of references for climate change InvEstigation. An overall presentation of the French GEODESIE project

    Science.gov (United States)

    Coulot, David; Richard, Jean-Yves

    2017-04-01

    Many major indicators of climate change are monitored with space observations (sea level rise from satellite altimetry, ice melting from dedicated satellites, etc.). This monitoring is highly dependent on references (positions and velocities of ground observing instruments, orbits of satellites, etc.) that only geodesy can provide. The current accuracy of these references does not permit to fully support the challenges that the constantly evolving Earth system gives rise to, and can consequently limit the accuracy of these indicators. For this reason, in the framework of the Global Geodetic Observing System (GGOS), stringent requirements are fixed to the International Terrestrial Reference Frame (ITRF) for the next decade: an accuracy at the level of 1 mm and a stability at the level of 0.1 mm/yr. This means an improvement of the current quality of ITRF by a factor of 5-10. Improving the quality of the geodetic references is an issue which requires a thorough reassessment of the methodologies involved. The most relevant and promising method to improve this quality is the direct combination (Combination at Observation Level - COL) of the space-geodetic measurements used to compute the official references of the International Earth Rotation and Reference Systems Service (IERS). The GEODESIE project aims at (i) determining highly-accurate global and consistent references (time series of Terrestrial Reference Frames and Celestial Reference Frames, of Earth's Orientation Parameters, and orbits of Earth's observation satellites) and (ii) providing the geophysical and climate research communities with these references, for a better estimation of geocentric sea level rise, ice mass balance and on-going climate changes. Time series of sea levels computed from altimetric data and tide gauge records with these references (orbits of satellite altimeters, Terrestrial Reference Frames and related vertical velocities of stations) will also be provided. The geodetic references

  2. Modeling laser wakefield accelerators in a Lorentz boosted frame

    Energy Technology Data Exchange (ETDEWEB)

    Vay, J.-L.; Geddes, C.G.R.; Cormier-Michel, E.; Grotec, D. P.

    2010-06-15

    Modeling of laser-plasma wakefield accelerators in an optimal frame of reference is shown to produce orders of magnitude speed-up of calculations from first principles. Obtaining these speedups requires mitigation of a high-frequency instability that otherwise limits effectiveness in addition to solutions for handling data input and output in a relativistically boosted frame of reference. The observed high-frequency instability is mitigated using methods including an electromagnetic solver with tunable coefficients, its extension to accomodate Perfectly Matched Layers and Friedman's damping algorithms, as well as an efficient large bandwidth digital filter. It is shown that choosing the frame of the wake as the frame of reference allows for higher levels of filtering and damping than is possible in other frames for the same accuracy. Detailed testing also revealed serendipitously the existence of a singular time step at which the instability level is minimized, independently of numerical dispersion, thus indicating that the observed instability may not be due primarily to Numerical Cerenkov as has been conjectured. The techniques developed for Cerenkov mitigation prove nonetheless to be very efficient at controlling the instability. Using these techniques, agreement at the percentage level is demonstrated between simulations using different frames of reference, with speedups reaching two orders of magnitude for a 0.1 GeV class stages. The method then allows direct and efficient full-scale modeling of deeply depleted laser-plasma stages of 10 GeV-1 TeV for the first time, verifying the scaling of plasma accelerators to very high energies. Over 4, 5 and 6 orders of magnitude speedup is achieved for the modeling of 10 GeV, 100 GeV and 1 TeV class stages, respectively.

  3. The Maxwell equations in a uniformly accelerated frame

    International Nuclear Information System (INIS)

    Torres del Castillo, G.F.; Perez S, C.I.

    2007-01-01

    The solution of the source-free Maxwell equations in a uniformly accelerated frame of reference is expressed in terms of a single complex scalar potential that obeys a second-order equation. The field of a static electric charge is obtained as an example of a stationary axisymmetric field. (Author)

  4. The discourse of liberation: Frames used in characterising the gay ...

    African Journals Online (AJOL)

    This article reports on the quantitative findings of a study that straddles the applied linguistic field of critical discourse analysis and a sociolinguistic field recently referred to as “queer linguistics”. Drawing on a quantitative method of analysis, the study investigates the linguistic framing of LGBT mobilisation in two South ...

  5. Effect of a large-scale distance variation of gravitational constant on the orbital elements of celestial bodies

    International Nuclear Information System (INIS)

    Li, L.-S.

    2009-01-01

    The effects of the variation of the gravitational constant with distance on the variation of the orbital elements of celestial objects are examined. The theoretical results show clearly that the large distance variation of the gravitational constant results in the periodic variation of the semi-major axis, eccentricity, longitude of the perihelion and the mean longitude, but it results in the secular variation of the longitude of the perihelion and the mean longitude, no secular variation for other orbital elements. As an example, the effects on four planets are estimated. Discussion and conclusion are drawn.

  6. Astronomy in the ancient world early and modern views on celestial events

    CERN Document Server

    McLeod, Alexus

    2016-01-01

    Alexus McLeod explores every aspect of the lesser-known history of astronomy in the Americas (Mesoamerica and North America), China and India, each through the frame of a particular astronomical phenomena. Part One considers the development of astronomy in the Americas as a response, in part, to the Supernova of 1054, which may have led to a cultural renaissance in astronomy. He then goes on to explore the contemporary understanding of supernovae, contrasting it with that of the ancient Americas.  Part Two is framed through the appearances of great comets, which had major divinatory significance in early China. The author discusses the advancement of observational astronomy in China, its influence on politics and its role in the survival or failure of empires.  Furthermore, the contemporary understanding of comets is also discussed for comparison.  Part Three, on India, considers the magnificent observatories of the Rajput king Jai Singh II, and the question of their purpose. The origins of Indian ast...

  7. Frames of exponentials:lower frame bounds for finite subfamilies, and approximation of the inverse frame operator

    DEFF Research Database (Denmark)

    Christensen, Ole; Lindner, Alexander M

    2001-01-01

    We give lower frame bounds for finite subfamilies of a frame of exponentials {e(i lambdak(.))}k is an element ofZ in L-2(-pi,pi). We also present a method for approximation of the inverse frame operator corresponding to {e(i lambdak(.))}k is an element ofZ, where knowledge of the frame bounds for...

  8. Enhancement Strategies for Frame-To Uas Stereo Visual Odometry

    Science.gov (United States)

    Kersten, J.; Rodehorst, V.

    2016-06-01

    Autonomous navigation of indoor unmanned aircraft systems (UAS) requires accurate pose estimations usually obtained from indirect measurements. Navigation based on inertial measurement units (IMU) is known to be affected by high drift rates. The incorporation of cameras provides complementary information due to the different underlying measurement principle. The scale ambiguity problem for monocular cameras is avoided when a light-weight stereo camera setup is used. However, also frame-to-frame stereo visual odometry (VO) approaches are known to accumulate pose estimation errors over time. Several valuable real-time capable techniques for outlier detection and drift reduction in frame-to-frame VO, for example robust relative orientation estimation using random sample consensus (RANSAC) and bundle adjustment, are available. This study addresses the problem of choosing appropriate VO components. We propose a frame-to-frame stereo VO method based on carefully selected components and parameters. This method is evaluated regarding the impact and value of different outlier detection and drift-reduction strategies, for example keyframe selection and sparse bundle adjustment (SBA), using reference benchmark data as well as own real stereo data. The experimental results demonstrate that our VO method is able to estimate quite accurate trajectories. Feature bucketing and keyframe selection are simple but effective strategies which further improve the VO results. Furthermore, introducing the stereo baseline constraint in pose graph optimization (PGO) leads to significant improvements.

  9. Sparsity and spectral properties of dual frames

    DEFF Research Database (Denmark)

    Krahmer, Felix; Kutyniok, Gitta; Lemvig, Jakob

    2013-01-01

    We study sparsity and spectral properties of dual frames of a given finite frame. We show that any finite frame has a dual with no more than $n^2$ non-vanishing entries, where $n$ denotes the ambient dimension, and that for most frames no sparser dual is possible. Moreover, we derive an expressio...

  10. 49 CFR 393.201 - Frames.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Frames. 393.201 Section 393.201 Transportation... SAFE OPERATION Frames, Cab and Body Components, Wheels, Steering, and Suspension Systems § 393.201 Frames. (a) The frame or chassis of each commercial motor vehicle shall not be cracked, loose, sagging or...

  11. Key Frame Extraction in the Summary Space.

    Science.gov (United States)

    Li, Xuelong; Zhao, Bin; Lu, Xiaoqiang

    2017-07-04

    Key frame extraction is an efficient way to create the video summary which helps users obtain a quick comprehension of the video content. Generally, the key frames should be representative of the video content, meanwhile, diverse to reduce the redundancy. Based on the assumption that the video data are near a subspace of a high-dimensional space, a new approach, named as key frame extraction in the summary space, is proposed for key frame extraction in this paper. The proposed approach aims to find the representative frames of the video and filter out similar frames from the representative frame set. First of all, the video data are mapped to a high-dimensional space, named as summary space. Then, a new representation is learned for each frame by analyzing the intrinsic structure of the summary space. Specifically, the learned representation can reflect the representativeness of the frame, and is utilized to select representative frames. Next, the perceptual hash algorithm is employed to measure the similarity of representative frames. As a result, the key frame set is obtained after filtering out similar frames from the representative frame set. Finally, the video summary is constructed by assigning the key frames in temporal order. Additionally, the ground truth, created by filtering out similar frames from human-created summaries, is utilized to evaluate the quality of the video summary. Compared with several traditional approaches, the experimental results on 80 videos from two datasets indicate the superior performance of our approach.

  12. Reed warbler orientation: initiation of nocturnal migratory flights in relation to visibility of celestial cues at dusk.

    Science.gov (United States)

    Åkesson, S.; Walinder, G.; Karlsson, L.; Ehnbom, S.

    2001-01-01

    We used radiotelemetry to investigate the time of migratory flight initiation relative to available celestial orientation cues and departure direction of a nocturnal passerine migrant, the reed warbler, Acrocephalus scirpaceus, during autumn migration. The study was carried out at Falsterbo, a coastal site in southwest Sweden. The warblers initiated migration from times well after local sunset and well into the night, corresponding to sun elevations between -4 degrees and -35 degrees, coinciding with the occurrence of stars at night. They departed in the expected migratory direction towards south of southwest with a few initiating migration in reverse directions towards northeast to east. Flight directions under overcast conditions (7-8/8) were more scattered than under clear sky conditions (0-4/8). There were fewer clouds on departure nights than on nights when the birds did not initiate migration. For birds staying longer than one night at stopover the horizontal visibility was higher and precipitation was less likely on departure nights than on the previous night. The results show that the visibility of celestial cues, and stars in particular, are important for the decision to initiate migration in reed warblers. However, cloud cover, horizontal visibility and precipitation might be correlated with other weather variables (i.e. wind or air pressure) that are also likely to be important for the decision to migrate. Copyright 2001 The Association for the Study of Animal Behaviour.

  13. Framing the future of fracking

    NARCIS (Netherlands)

    Metze, Tamara

    2017-01-01

    Hydraulic fracturing is a technology developed to improve and increase the production of natural gas. In many countries, including the Netherlands, it has caused environmental controversies. In these controversies, 'futurity framing' may open up debates for alternative paradigms such as

  14. Frame Rate and Human Vision

    Science.gov (United States)

    Watson, Andrew B.

    2012-01-01

    To enhance the quality of the theatre experience, the film industry is interested in achieving higher frame rates for capture and display. In this talk I will describe the basic spatio-temporal sensitivities of human vision, and how they respond to the time sequence of static images that is fundamental to cinematic presentation.

  15. EO framing flight test results

    Science.gov (United States)

    Lareau, Andre G.

    1995-09-01

    Recon/Optical, Inc. (ROI) has pioneered the electro-optical (E-O) framing generation of sensors with the CA-260, a KS-87 form/fit camera with a wafer-scale focal plane array (FPA) containing a patented, on-chip, forward motion compensation (FMC) architecture. The technology has now matured to the state where production E-O framing cameras are form/fit replacing their former film counterparts. During this interim production phase, flight demonstrations and tests are continuing to prove that E-O framing produces high-quality imagery, is robust to various platforms and mission tactics, interoperable with existing and planned C3I architectures, affordable and available, and meets the war-fighters needs. This paper discusses flight test results of the CA-260 E-O framing sensor flown in the F-14A TARPS during September 1994. This demonstration provided some unique imagery permitting a comparison of low-light level, in-flight FMC-on versus FMC-off performance. A first-level comparison of the resulting imagery based upon predicted FMC performance and post- processing numerical analysis is presented. The results indicae that the patented FMC architecture performed as predicted, and that for low-light conditions resulting in limited SNR images, on-chip FMC can provide a significant image quality improvement over post- processing alternatives.

  16. Quantum strategies in moving frames

    International Nuclear Information System (INIS)

    Tan Jianchuan; Wang Anmin

    2009-01-01

    We investigate quantum strategies in moving frames by considering Prisoners' Dilemma and propose four thresholds of γ for two players to determine their Nash Equilibria. We find that the relativistic operations could enhance or diminish the quantum features of the game for different players who move in different directions relative to the arbiter

  17. Media framing and social movements

    NARCIS (Netherlands)

    Vliegenthart, R.; Snow, D.A.; Della Porta, D.; Klandermans, B.; McAdam, D.

    2013-01-01

    In their study of media content, mass communication scholars commonly rely on Entman's (1993: 52) definition of framing: "[selecting] some aspects of a perceived reality and make them more salient in a communicating text, in such a way as to promote a particular problem definition, causal

  18. Quantum strategies in moving frames

    Energy Technology Data Exchange (ETDEWEB)

    Tan Jianchuan [Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China)], E-mail: tanjc@mail.ustc.edu.cn; Wang Anmin [Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China)], E-mail: anmwang@ustc.edu.cn

    2009-02-16

    We investigate quantum strategies in moving frames by considering Prisoners' Dilemma and propose four thresholds of {gamma} for two players to determine their Nash Equilibria. We find that the relativistic operations could enhance or diminish the quantum features of the game for different players who move in different directions relative to the arbiter.

  19. G-frames with bounded linear operators

    OpenAIRE

    Xiao, Xiang-chun; Zhu, Yu-can; Shu, Zhi-biao; Ding, Ming-ling

    2015-01-01

    In this paper, we introduce the more general g-frame which is called a $K$-g-frame by combining a g-frame with a bounded linear operator $K$ in a Hilbert space. We give several equivalent characterizations for $K$-g-frames and discuss the stability of perturbation for $K$-g-frames. We also investigate the relationship between a $K$-g-frame and the range of the bounded linear operator $K$. In the end, we give two sufficient conditions for the remainder of a $K$-g-frame after an erasure to stil...

  20. Framing and misperception in public good experiments

    DEFF Research Database (Denmark)

    Fosgaard, Toke Reinholt; Hansen, Lars Gårn; Wengström, Erik Roland

    2017-01-01

    Earlier studies have found that framing has substantial impact on the degree of cooperation observed in public good experiments. We show that the way the public good game is framed affects misperceptions about the incentives of the game. Moreover, we show that such framing-induced differences...... in misperceptions are linked to the framing effect on subjects' cooperation behavior. When we do not control for the different levels of misperceptions between frames, we observe a significant framing effect on subjects’ cooperation preferences. However, this framing effect becomes insignificant once we remove...

  1. Recent references

    International Nuclear Information System (INIS)

    Ramavataram, S.

    1991-01-01

    In support of a continuing program of systematic evaluation of nuclear structure data, the National Nuclear Data Center maintains a complete computer file of references to the nuclear physics literature. Each reference is tagged by a keyword string, which indicates the kinds of data contained in the article. This master file of Nuclear Structure References (NSR) contains complete keyword indexes to literature published since 1969, with partial indexing of older references. Any reader who finds errors in the keyword descriptions is urged to report them to the National Nuclear Data Center so that the master NSR file can be corrected. In 1966, the first collection of Recent References was published as a separate issue of Nuclear Data Sheets. Every four months since 1970, a similar indexed bibliography to new nuclear experiments has been prepared from additions to the NSR file and published. Beginning in 1978, Recent References was cumulated annually, with the third issue completely superseding the two issues previously published during a given year. Due to publication policy changes, cumulation of Recent Reference was discontinued in 1986. The volume and issue number of all the cumulative issues published to date are given. NNDC will continue to respond to individual requests for special bibliographies on nuclear physics topics, in addition to those easily obtained from Recent References. If the required information is available from the keyword string, a reference list can be prepared automatically from the computer files. This service can be provided on request, in exchange for the timely communication of new nuclear physics results (e.g., preprints). A current copy of the NSR file may also be obtained in a standard format on magnetic tape from NNDC. Requests for special searches of the NSR file may also be directed to the National Nuclear Data Center

  2. The research of the coupled orbital-attitude controlled motion of celestial body in the neighborhood of the collinear libration point L1

    Science.gov (United States)

    Shmyrov, A.; Shmyrov, V.; Shymanchuk, D.

    2017-10-01

    This article considers the motion of a celestial body within the restricted three-body problem of the Sun-Earth system. The equations of controlled coupled attitude-orbit motion in the neighborhood of collinear libration point L1 are investigated. The translational orbital motion of a celestial body is described using Hill's equations of circular restricted three-body problem of the Sun-Earth system. Rotational orbital motion is described using Euler's dynamic equations and quaternion kinematic equation. We investigate the problem of stability of celestial body rotational orbital motion in relative equilibrium positions and stabilization of celestial body rotational orbital motion with proposed control laws in the neighborhood of collinear libration point L1. To study stabilization problem, Lyapunov function is constructed in the form of the sum of the kinetic energy and special "kinematic function" of the Rodriguez-Hamiltonian parameters. Numerical modeling of the controlled rotational motion of a celestial body at libration point L1 is carried out. The numerical characteristics of the control parameters and rotational motion are given.

  3. Frame covariant nonminimal multifield inflation

    Directory of Open Access Journals (Sweden)

    Sotirios Karamitsos

    2018-02-01

    Full Text Available We introduce a frame-covariant formalism for inflation of scalar-curvature theories by adopting a differential geometric approach which treats the scalar fields as coordinates living on a field-space manifold. This ensures that our description of inflation is both conformally and reparameterization covariant. Our formulation gives rise to extensions of the usual Hubble and potential slow-roll parameters to generalized fully frame-covariant forms, which allow us to provide manifestly frame-invariant predictions for cosmological observables, such as the tensor-to-scalar ratio r, the spectral indices nR and nT, their runnings αR and αT, the non-Gaussianity parameter fNL, and the isocurvature fraction βiso. We examine the role of the field space curvature in the generation and transfer of isocurvature modes, and we investigate the effect of boundary conditions for the scalar fields at the end of inflation on the observable inflationary quantities. We explore the stability of the trajectories with respect to the boundary conditions by using a suitable sensitivity parameter. To illustrate our approach, we first analyze a simple minimal two-field scenario before studying a more realistic nonminimal model inspired by Higgs inflation. We find that isocurvature effects are greatly enhanced in the latter scenario and must be taken into account for certain values in the parameter space such that the model is properly normalized to the observed scalar power spectrum PR. Finally, we outline how our frame-covariant approach may be extended beyond the tree-level approximation through the Vilkovisky–De Witt formalism, which we generalize to take into account conformal transformations, thereby leading to a fully frame-invariant effective action at the one-loop level.

  4. Frame covariant nonminimal multifield inflation

    Science.gov (United States)

    Karamitsos, Sotirios; Pilaftsis, Apostolos

    2018-02-01

    We introduce a frame-covariant formalism for inflation of scalar-curvature theories by adopting a differential geometric approach which treats the scalar fields as coordinates living on a field-space manifold. This ensures that our description of inflation is both conformally and reparameterization covariant. Our formulation gives rise to extensions of the usual Hubble and potential slow-roll parameters to generalized fully frame-covariant forms, which allow us to provide manifestly frame-invariant predictions for cosmological observables, such as the tensor-to-scalar ratio r, the spectral indices nR and nT, their runnings αR and αT, the non-Gaussianity parameter fNL, and the isocurvature fraction βiso. We examine the role of the field space curvature in the generation and transfer of isocurvature modes, and we investigate the effect of boundary conditions for the scalar fields at the end of inflation on the observable inflationary quantities. We explore the stability of the trajectories with respect to the boundary conditions by using a suitable sensitivity parameter. To illustrate our approach, we first analyze a simple minimal two-field scenario before studying a more realistic nonminimal model inspired by Higgs inflation. We find that isocurvature effects are greatly enhanced in the latter scenario and must be taken into account for certain values in the parameter space such that the model is properly normalized to the observed scalar power spectrum PR. Finally, we outline how our frame-covariant approach may be extended beyond the tree-level approximation through the Vilkovisky-De Witt formalism, which we generalize to take into account conformal transformations, thereby leading to a fully frame-invariant effective action at the one-loop level.

  5. Modeling laser wakefield accelerators in a Lorentz boosted frame

    Energy Technology Data Exchange (ETDEWEB)

    Vay, J.-L.; Geddes, C.G.R.; Cormier-Michel, E.; Grote, D.P.

    2010-09-15

    Modeling of laser-plasma wakefield accelerators in an optimal frame of reference [1] is shown to produce orders of magnitude speed-up of calculations from first principles. Obtaining these speedups requires mitigation of a high frequency instability that otherwise limits effectiveness in addition to solutions for handling data input and output in a relativistically boosted frame of reference. The observed high-frequency instability is mitigated using methods including an electromagnetic solver with tunable coefficients, its extension to accomodate Perfectly Matched Layers and Friedman's damping algorithms, as well as an efficient large bandwidth digital filter. It is shown that choosing theframe of the wake as the frame of reference allows for higher levels of filtering and damping than is possible in other frames for the same accuracy. Detailed testing also revealed serendipitously the existence of a singular time step at which the instability level is minimized, independently of numerical dispersion, thus indicating that the observed instability may not be due primarily to Numerical Cerenkov as has been conjectured. The techniques developed for Cerenkov mitigation prove nonetheless to be very efficient at controlling the instability. Using these techniques, agreement at the percentage level is demonstrated between simulations using different frames of reference, with speedups reaching two orders of magnitude for a 0.1 GeV class stages. The method then allows direct and efficient full-scale modeling of deeply depleted laser-plasma stages of 10 GeV-1 TeV for the first time, verifying the scaling of plasma accelerators to very high energies. Over 4, 5 and 6 orders of magnitude speedup is achieved for the modeling of 10 GeV, 100 GeV and 1 TeV class stages, respectively.

  6. celestial empire” in the eighteenth and nineteenth century ... - AJOL

    African Journals Online (AJOL)

    User

    dal XVII al XX secolo”, Cina, 3, 1957:56f; G. Tucci, Italia e Oriente, Rome: ISIAO, 2005, passim. A still useful survey ... pamphlets, defending or accusing the Jesuits, appeared from the. 1680s to 1745, when the ... There is a growing literature on China in eighteenth century France and Europe in general. A standard reference ...

  7. Mixed-frame and stationary-frame repetitive control schemes for compensating typical load and grid harmonics

    DEFF Research Database (Denmark)

    Loh, P.; Tang, Y.; Blaabjerg, Frede

    2011-01-01

    the positive- and negative-sequence fundamental currents, which are known to directly influence the flow of active and reactive power in most energy conversion systems. Moreover, for the tracking or compensation of harmonics, the controllers include a repetitive control path in either the synchronous...... or stationary frame, whose inherent feedback and feedforward structure is proven to resemble a bank of resonant filters in either reference frames. Unlike other existing controllers, the proposed repetitive controllers function by introducing multiple resonant peaks at only those harmonic frequencies typically...

  8. Universal tectonic dichotomy of small celestial bodies expressed in their common convexo-concave shapes

    Science.gov (United States)

    Kochemasov, G. G.

    2008-09-01

    The wave planetology [1, 2, 3 & others] declares in its first theorem that all celestial bodies are dichotomous. This is a result of a warping action of the fundamental wave (wave 1 long 2πR where R is a body radius) that appears in any body due to its movement in non-round (elliptical, parabolic) keplerian orbits with periodically changing accelerations. Having a standing character and four crossing directions in rotating bodies (but all bodies rotate!) these waves inevitably press in one hemisphere and bulge out the opposite one tending to impose on a body convexo-concave shape. This shape is leveled out in larger bodies due to enhanced gravity but is clearly observed in smaller ones with diminished gravity. Still, in the larger bodies as, for an example, in Earth the tectonic dichotomy is expressed as an opposition of the subsided western Pacific hemisphere and the uplifted eastern continental hemisphere. At Mars even sharper dichotomy is in the north-south direction. Small bodies (normally less than 400-500 km across) notwithstanding their type (asteroids, comets, satellites), size and composition (stones, metals, ices) are flattened and bended by the fundamental wave. That is why all asteroids in the main asteroid belt have an oblong shape what was established rather long ago but never was properly explained. Now a number of small satellites is observed by Cassini spacecraft in the saturnian system that makes together with jovian and martian small satellites a representative group for comparisons. In the figures below are shown asteroids, satellites and a comet arranged in a row of increasing sizes. They all are flattened except the largest in the row Enceladus (505 km) and bended tending to acquire a convexo-concave shape. Asteroids: Itokawa (0.5 km long), Eros (33 km, PIA03111). Satellites: Calypso (22 km, PIA07633), Atlas (32 km, PIA08233), Prometheus (102 km, PIA08192), Hyperion (350 km, PIA06645), Enceladus (505 km, PIA08258, comet-like behaviour). Comet

  9. Unified Selenocentric Reference Coordinates Net in the Dynamic System

    Science.gov (United States)

    Nefedyev, Yuri; Petrova, Natalia; Varaksina, Natalia

    In this report the task of the making selenocentric inertial reference net is solved. The purpose is making summary reference net by expansion KSC-1162 selenodetic system using 12 cosmic and ground selenodesic catalogues. The prospective analysis of this net was performed. These selenocentric reference catalogue covers full visible and a part of far lunar sides. Modern cosmic technologies need the accurate coordinate - temporal support including reference frame realization, inertial and dynamic system orientation and studying dynamic and geometry celestial bodies. That refers to dynamic and geometric selenocentric lunar parameters. The catalogue based on mission “Apollo” and reference nets of the west lunar hemisphere made by missions “Zond 5”, ”Zond 8” cover small part of the Moon surface. Three ALSEP stations were used to transform “Apollo” topographic coordinates. Transformation mean-square errors are less than 80 meters and measurement’s errors are about 60 meters. On this account positions inaccuracy near and between ALSEP stations are less 150 meters. The offset from place of the location ALSEP enlarges the supposed mistake is more than 300 m and this is a major part of the lunar surface. In solving the problem of high-precision condensation and expansion of fundamental selenocentric net KSC-1162 on the visible side of the Moon and lunar far side were obtained following new results: a) the analysis and investigation of the accuracy of basic net contained in ULCN were carried out; b) the decryption of common objects for coordinate systems which are being explored was executed; c) the extension of the mathematical content package TSC was carried out; d) the development of TSC as an expert system of universal transformation planet's coordinates was carried out; e) the possibility of applying the ARM-approach to the problem TC on common objects, which allows to find optimal parameter estimation and model structure of TC was confirmed; f) the

  10. Frame model of knowledge in quality control systems

    Energy Technology Data Exchange (ETDEWEB)

    Macherauskas, V.Yu.

    1982-09-01

    The purpose of this article is to develop a semiotic model for representation of data and knowledge in a system for supplying operational information to management personnel on the progress of a technological process, with the aim of enabling an analysis of deviations of product quality and formulation of recommendations to the technologists as to how to eliminate them. Since any knowledge of people that can be realistically utilized in machine systems is represented in natural language form, special languages for representation of knowledge, based on the concept of frames, are being developed for formation of semiotic models in computers. This article defines the frames, followed by a description of a mechanism of knowledge manipulation and of some aspects of realization of a frame model of knowledge. 9 references.

  11. Variance based OFDM frame synchronization

    Directory of Open Access Journals (Sweden)

    Z. Fedra

    2012-04-01

    Full Text Available The paper deals with a new frame synchronization scheme for OFDM systems and calculates the complexity of this scheme. The scheme is based on the computing of the detection window variance. The variance is computed in two delayed times, so a modified Early-Late loop is used for the frame position detection. The proposed algorithm deals with different variants of OFDM parameters including guard interval, cyclic prefix, and has good properties regarding the choice of the algorithm's parameters since the parameters may be chosen within a wide range without having a high influence on system performance. The verification of the proposed algorithm functionality has been performed on a development environment using universal software radio peripheral (USRP hardware.

  12. Meta framing and polyphonic structures

    DEFF Research Database (Denmark)

    Pedersen, Karsten

    2017-01-01

    The present case study deals with the Danish tabloid BT’s coverage of Cycling team owner Bjarne Riis’s possible knowledge of doping use in his cycling teams. BT sees itself as a sports paper and tries to signal that it takes sports coverage as seriously other kinds of news. We see that reflected...... and mapping the entire news output in one specified week, and draws on insights from framing theory as well as polyphony theory....

  13. Predicting the Strength of Online News Frames

    Directory of Open Access Journals (Sweden)

    Hrvoje Jakopović

    2017-10-01

    Full Text Available Framing theory is one of the most significant approaches to understanding media and their potential impact on publics. Leaving aside that fact, the author finds that publicity effects seem to be dispersed and difficult to catch for public relations. This article employs a specific research design, which could be applied to public relations practice, namely with a view to observing correlations between specific media frames and individual frames. The approach is based on the typology of news frames. The author attributes negative, positive and neutral determinants to the types of frames in his empirical research. Online news regarding three transport organizations and the accompanying user comments (identified as negative, positive and neutral are analysed by means of the method of content and sentiment analysis. The author recognizes user comments and reviews as individual frames that take part in the creation of online image. Furthermore, he identifies the types of media frames as well as individual frames manifested as image, and undertakes correlation research in order to establish their prediction potential. The results expose the most frequently used types of media frames concerning the transport domain. The media are keen to report through the attribution of responsibility frame, and after that, through the economic frame and the conflict frame, but, on the other hand, they tend to neglect the human interest frame and the morality frame. The results show that specific types of news frames enable better prediction of user reactions. The economic frame and the human interest frame therefore represent the most predictable types of frame.

  14. Frames and generalized shift-invariant systems

    DEFF Research Database (Denmark)

    Christensen, Ole

    2004-01-01

    With motivation from the theory of Hilbert-Schmidt operators we review recent topics concerning frames in L 2 (R) and their duals. Frames are generalizations of orthonormal bases in Hilbert spaces. As for an orthonormal basis, a frame allows each element in the underlying Hilbert space to be writ......With motivation from the theory of Hilbert-Schmidt operators we review recent topics concerning frames in L 2 (R) and their duals. Frames are generalizations of orthonormal bases in Hilbert spaces. As for an orthonormal basis, a frame allows each element in the underlying Hilbert space...

  15. Monolithic LTCC seal frame and lid

    Energy Technology Data Exchange (ETDEWEB)

    Krueger, Daniel S.; Peterson, Kenneth A.; Stockdale, Dave; Duncan, James Brent; Riggs, Bristen

    2016-06-21

    A method for forming a monolithic seal frame and lid for use with a substrate and electronic circuitry comprises the steps of forming a mandrel from a ceramic and glass based material, forming a seal frame and lid block from a ceramic and glass based material, creating a seal frame and lid by forming a compartment and a plurality of sidewalls in the seal frame and lid block, placing the seal frame and lid on the mandrel such that the mandrel fits within the compartment, and cofiring the seal frame and lid block.

  16. Privateering and profiteering on the moon and other celestial bodies: Debunking the myth of property rights in space

    Science.gov (United States)

    Sterns, P. M.; Tennen, L. I.

    2003-06-01

    The increasing role ofthe private sector in space creates virtually limitless opportunities. It is axiomatic that activities in space must be conducted in compliance with the applicable requirements of the body of space law. Unfortunately, in their zeal to manufacture a profit, some proponents give insufficient consideration to the implications and ramifications of their ventures vis-a-vis the extant law of outer space, particularly in relation to the non-appropriation principle. Still other purveyors ofproposals are more disingenuous, proffering elaborate yet analytically inadequate rationales to justify either abrogating or disregarding the legal framework applicable to activities in space, especially in regard to assertions of so called "property rights" in space, on the Moon, and on other celestial bodies. This article examines the fallacies of these propositions, and demonstrates that such claims of property rights are both unnecessary and counterproductive to the development of commercial space.

  17. The limit passage of space curvature in problems of celestial mechanics with the generalized Kepler and Hooke potentials

    Science.gov (United States)

    Vozmishcheva, Tatiana

    2016-09-01

    The connection between the problems of celestial mechanics: the Kepler problem, the two-center problem and the two body problem in spaces of constant curvature with the generalized Kepler and Hooke potentials is investigated. The limit passage in the two-center and two body problems in the Lobachevsky space and on a sphere is carried out as λto0 (λ is the curvature of the corresponding space) for the two potentials. The potentials and metrics in spaces under study are written in the gnomonic coordinates. It is shown that as the curvature radius tends to infinity, the generalized gravitational and elastic potentials transform to the Kepler and Hooke forms in the Euclidean space.

  18. The Discovery of the Regular Movements of Celestial Bodies and the Development of Monotheism in the Ancient Near East

    Science.gov (United States)

    Lanfranchi, G. B.

    2011-06-01

    For Ancient Mesopotamians, astronomical phenomena were signs signifying the gods' judgment on human behaviour. Mesopotamian scholars studied celestial phenomena for understanding the gods' will, and strongly developed astrology. From the 8th to the 6th century BC Assyrian and Babylonian astronomers achieved the ability to predict solar and lunar eclipses, and the planets' movements through mathematical calculations. Predictability of astral phenomena solicited the awareness that they are all regular, and that the universe is governed by an eternal, immutable order fixed at its very beginning. This finally favoured the idea that the cosmic order depended on the will of one god only, displacing polytheism in favour of monotheism; and astrology lost its religious importance as a mean to know the divine will.

  19. Selection pressure in alternative reading frames.

    Directory of Open Access Journals (Sweden)

    Katharina Mir

    Full Text Available Overlapping genes are two protein-coding sequences sharing a significant part of the same DNA locus in different reading frames. Although in recent times an increasing number of examples have been found in bacteria the underlying mechanisms of their evolution are unknown. In this work we explore how selective pressure in a protein-coding sequence influences its overlapping genes in alternative reading frames. We model evolution using a time-continuous Markov process and derive the corresponding model for the remaining frames to quantify selection pressure and genetic noise. Our findings lead to the presumption that, once information is embedded in the reverse reading frame -2 (relative to the mother gene in +1 purifying selection in the protein-coding reading frame automatically protects the sequences in both frames. We also found that this coincides with the fact that the genetic noise measured using the conditional entropy is minimal in frame -2 under selection in the coding frame.

  20. QUADCOPTER BODY FRAME MODEL AND ANALYSIS

    OpenAIRE

    KUANTAMA Endrowednes; CRACIUN Dan; TARCA Radu

    2016-01-01

    Quadcopter frame modeling is useful to analyze the reliability of body frame part and to help determine the type of rotor and propeller in order to assure the necessary flight acceleration. Quadcopter flight stability is influenced by the resulting thrust, by the distance between each rotor propeller and also by the frame rigidity; the frame has been designed to be as light as possible, meanwhile maintaining the strength to carry the load. Solidworks software has been used to design and analy...

  1. Reciprocal frame architecture in Japan

    OpenAIRE

    POPOVIC LARSEN, Olga

    2010-01-01

    p. 1866-1876 Reciprocal Frame Structures (RF) are a form of a three-dimensional grillage structure. In their simplest configuration they are formed by placing beams in a closed circuit in which each beam is supported by the preceding beam at the inner end, and by an external wall or ring beam on the outer end. In their more complex configurations gridshell-like structures with a double curvature can be formed. Although RFs have been used in many countries throughout history and are k...

  2. Oversampling of wavelet frames for real dilations

    DEFF Research Database (Denmark)

    Bownik, Marcin; Lemvig, Jakob

    2012-01-01

    We generalize the Second Oversampling Theorem for wavelet frames and dual wavelet frames from the setting of integer dilations to real dilations. We also study the relationship between dilation matrix oversampling of semi-orthogonal Parseval wavelet frames and the additional shift invariance gain...

  3. Influence of framing on medical decision making

    OpenAIRE

    Gong, Jingjing; Zhang, Yan; Feng, Jun; Huang, Yonghua; Wei, Yazhou; Zhang, Weiwei

    2013-01-01

    Numerous studies have demonstrated the robustness of the framing effect in a variety of contexts, especially in medical decision making. Unfortunately, research is still inconsistent as to how so many variables impact framing effects in medical decision making. Additionally, much attention should be paid to the framing effect not only in hypothetical scenarios but also in clinical experience.

  4. Fight or flight: Affective news framing effects

    NARCIS (Netherlands)

    Feinholdt, A.

    2016-01-01

    This dissertation investigates how emotions shape and are shaped by news framing and how this interplay leads to a number of affective news framing effects. My work reveals that emotions do not only function as mechanisms but also as channels strengthening or weakening framing effects. In addition,

  5. Computable Frames in Computable Banach Spaces

    Directory of Open Access Journals (Sweden)

    S.K. Kaushik

    2016-06-01

    Full Text Available We develop some parts of the frame theory in Banach spaces from the point of view of Computable Analysis. We define computable M-basis and use it to construct a computable Banach space of scalar valued sequences. Computable Xd frames and computable Banach frames are also defined and computable versions of sufficient conditions for their existence are obtained.

  6. Influence of framing on medical decision making

    Science.gov (United States)

    Gong, Jingjing; Zhang, Yan; Feng, Jun; Huang, Yonghua; Wei, Yazhou; Zhang, Weiwei

    2013-01-01

    Numerous studies have demonstrated the robustness of the framing effect in a variety of contexts, especially in medical decision making. Unfortunately, research is still inconsistent as to how so many variables impact framing effects in medical decision making. Additionally, much attention should be paid to the framing effect not only in hypothetical scenarios but also in clinical experience. PMID:27034630

  7. 21 CFR 886.5842 - Spectacle frame.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Spectacle frame. 886.5842 Section 886.5842 Food... DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5842 Spectacle frame. (a) Identification. A spectacle frame is a device made of metal or plastic intended to hold prescription spectacle lenses worn by a...

  8. 10 CFR 710.35 - Time frames.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Time frames. 710.35 Section 710.35 Energy DEPARTMENT OF... Matter or Special Nuclear Material Miscellaneous § 710.35 Time frames. Statements of time established for processing aspects of a case under this subpart are the agency's desired time frames in implementing the...

  9. Evaluation and the Framing of Race

    Science.gov (United States)

    House, Ernest R.

    2017-01-01

    Racial framing can have strong effects on programs, policies, and even evaluations. Racial framing developed as a justification for the exploitation of minorities and has been a primary causal factor in the persistence of racism. By being aware of its pattern, structure, origins, and how racial framing generates effects, we can significantly…

  10. PARAMETRIC RESONANSE IN STATICALLY INDETERMINATE FRAMES

    Directory of Open Access Journals (Sweden)

    Yu.V. Vorona

    2014-12-01

    Full Text Available The technique for development and reduction of discrete dynamics models of frames is presented. Construction of the models is carried out using finite element method, generalized coordinates and tools of modern computer software. Parametric resonance in a statically indeterminate frame caused by external excitations is investigated. Main instability domains of the frame are determined.

  11. Parametric Study Of Window Frame Geometry

    DEFF Research Database (Denmark)

    Zajas, Jan Jakub; Heiselberg, Per

    2013-01-01

    This paper describes a parametric study on window frame geometry with the goal of designing frames with very good thermal properties. Three different parametric frame models are introduced, deseribed by a number of variables. In the first part of the study, a process of sensitivity analysis...

  12. Center of Mass of Two or More Celestial Bodies as a Basis of Comets and «Black Holes» Mechanism

    Directory of Open Access Journals (Sweden)

    Eugeny F. Orlov

    2012-04-01

    Full Text Available The article considers the questions, arising during rendezvous of two celestial bodies with equal mass, one of which is the Earth and the consequences of such rendezvous to modern civilization, suggests the idea of centers of galaxies mass with anomalously large values of the gravitational fields, which allows to divide them into two types – material filled and hollow.

  13. Rigid Motion and Adapted Frames

    Science.gov (United States)

    Lyle, Stephen N.

    The aim here is to describe the rigid motion of a continuous medium in special and general relativity. Section 7.1 defines a rigid rod in special relativity, and Sect. 7.2 shows the link with the space coordinates of a certain kind of accelerating frame in flat spacetimes. Section 7.3 then sets up a notation for describing the arbitrary smooth motion of a continuous medium in general curved spacetimes, defining the proper metric of such a medium. Section 7.4 singles out rigid motions and shows that the rod in Sect. 7.1 undergoes rigid motion in the more generally defined sense. Section 7.5 defines a rate of strain tensor for a continuous medium in general relativity and reformulates the rigidity criterion. Section 7.6 aims to classify all possible rigid motions in special relativity, reemphasizing the link with semi-Euclidean frames adapted to accelerating observers in special relativity. Then, Sects. 7.7 and 7.8 describe rigid motion without rotation and rigid rotation, respectively. Along the way we introduce the notion of Fermi-Walker transport and discuss its relevance for rigid motions. Section 7.9 brings together all the above themes in an account of a recent generalization of the notion of uniform acceleration, thereby characterizing a wide class of rigid motions.

  14. Nonlinear pushover analysis of infilled concrete frames

    Science.gov (United States)

    Huang, Chao Hsun; Tuan, Yungting Alex; Hsu, Ruo Yun

    2006-12-01

    Six reinforced concrete frames with or without masonry infills were constructed and tested under horizontal cyclic loads. All six frames had identical details in which the transverse reinforcement in columns was provided by rectangular hoops that did not meet current ACI specifications for ductile frames. For comparison purposes, the columns in three of these frames were jacketed by carbon-fiber-reinforced-polymer (CFRP) sheets to avoid possible shear failure. A nonlinear pushover analysis, in which the force-deformation relationships of individual elements were developed based on ACI 318, FEMA 356, and Chen’s model, was carried out for these frames and compared to test results. Both the failure mechanisms and impact of infills on the behaviors of these frames were examined in the study. Conclusions from the present analysis provide structural engineers with valuable information for evaluation and design of infilled concrete frame building structures.

  15. An introduction to finite tight frames

    CERN Document Server

    Waldron, Shayne F D

    2018-01-01

    This textbook is an introduction to the theory and applications of finite tight frames, an area that has developed rapidly in the last decade. Stimulating much of this growth are the applications of finite frames to diverse fields such as signal processing, quantum information theory, multivariate orthogonal polynomials, and remote sensing. Key features and topics: * First book entirely devoted to finite frames * Extensive exercises and MATLAB examples for classroom use * Important examples, such as harmonic and Heisenberg frames, are presented in preliminary chapters, encouraging readers to explore and develop an intuitive feeling for tight frames * Later chapters delve into general theory details and recent research results * Many illustrations showing the special aspects of the geometry of finite frames * Provides an overview of the field of finite tight frames * Discusses future research directions in the field Featuring exercises and MATLAB examples in each chapter, the book is well suited as a textbook ...

  16. Analisis Framing dalam Riset Public Relations

    Directory of Open Access Journals (Sweden)

    NARAYANA MAHENDRA PRASTYA

    2016-12-01

    Full Text Available This paper aims to give description about how to use frame analysis in Public Relations (PR research. The author use two framing models: Entman and Pan & Kosicki. The object is organization official statement about particular issue. Frame analysis method rarely used in Public Relations research. This methods commonly use in journalism study, to analyse the news in media. Meanwhile, the key word of framing is the social construction of reality. Organization can make social construction of realty in their official statement. In acacemic term, frame analysis in PR research is useful to know how organization positioned themselves in particular situation. Other benefit is use to evaluat whether the organization frame is conformable with the public opinion or agenda setting media or not. In practical term, frame analysis give benefit for PR practitioner to create the message that can be undserstood by public, also give positive image for organization.

  17. Characterization of Oblique Dual Frame Pairs

    DEFF Research Database (Denmark)

    Christensen, Ole; Eldar, Yonina

    2006-01-01

    Given a frame for a subspace W of a Hilbert space H, we consider all possible families of oblique dual frame vectors on an appropriately chosen subspace V. In place of the standard description, which involves computing the pseudoinverse of the frame operator, we develop an alternative...... characterization which in some cases can be computationally more efficient. We first treat the case of a general frame on an arbitrary Hilbert space, and then specialize the results to shift-invariant frames with multiple generators. In particular, we present explicit versions of our general conditions...... for the case of shift-invariant spaces with a single generator. The theory is also adapted to the standard frame setting in which the original and dual frames are defined on the same space. Copyright (C) 2006 Hindawi Publishing Corporation. All rights reserved....

  18. A criança celestial: perambulações entre aruanda e o inconsciente coletivo

    Directory of Open Access Journals (Sweden)

    Júlia Ritez Martins

    2009-12-01

    Full Text Available Tendo em vista que a religião umbandista expressa e explicita etnoteorias psicológicas afro-brasileiras, esta pesquisa visou explicitar os sentidos associados a sua concepção do infantil, mediante o estudo de um dos principais personagens do seu panteão, os espíritos de crianças. Para efeito de contraste e no intuito de auxiliar a organizar as concepções umbandistas, tomou-se como referência a psicologia junguiana. Combinou-se a observação participante com a realização de entrevistas com praticantes da religião e com médiuns em transe de espíritos infantis. Observou-se que esses espíritos revelam-se principalmente por formas não verbais de comunicação. As aproximações no plano da significação entre o arquétipo do puer e a manifestação espiritual de crianças na umbanda devem ser feitas com cuidado e a assimilação destas àquele só pode ser feita mediante uma sobreposição de uma concepção de psíquico a uma etnoteoria diversa.

  19. Discursive Framings of Human Rights

    DEFF Research Database (Denmark)

    What does it mean to be a subject of human rights? The status of the subject is closely connected with the form and rhetoric of the framing discourse, and this book investigates the relationship between the status of the subject and the form of human rights discourse, in differing aesthetic...... and social contexts. Historical as well as contemporary declarations of rights have stressed both the protective and political aspects of human rights. But in concrete situations and conflictual moments, the high moral legitimacy of human rights rhetoric has often clouded the actual character of specific...... interventions, and so made it difficult to differentiate between the objects of humanitarian intervention and the subjects of politics. Critically re-examining this opposition – between victims and agents of human rights – through a focus on the ways in which discourses of rights are formed and circulated...

  20. Time reference teased apart from tense : Thinking beyond the present

    NARCIS (Netherlands)

    Bos, Laura S.; Dragoy, Olga; Stowe, Laurie A.; Bastiaanse, Roelien

    Reference to a time frame in which an event takes place can be done by verb inflection. lithe time frame (past, present, future) is set by a temporal adverb, the verb inflection should correspond (yesterday he walked; today he walks). Temporal violations by simple verbs (single, lexical verbs

  1. Self- and Other-Referent Criteria of Career Success.

    Science.gov (United States)

    Heslin, Peter A.

    2003-01-01

    Business students (n=71) evaluated their career success thus far. Framed by social comparison theory, results showed that 68% used other-referent criteria to assess their success. Participants who believed that ability and personality are fixed attributes had greater reliance on other-referent criteria. (Contains 100 references.) (SK)

  2. Image quality assessment metric for frame accumulated image

    Science.gov (United States)

    Yu, Jianping; Li, Gang; Wang, Shaohui; Lin, Ling

    2018-01-01

    The medical image quality determines the accuracy of diagnosis, and the gray-scale resolution is an important parameter to measure image quality. But current objective metrics are not very suitable for assessing medical images obtained by frame accumulation technology. Little attention was paid to the gray-scale resolution, basically based on spatial resolution and limited to the 256 level gray scale of the existing display device. Thus, this paper proposes a metric, "mean signal-to-noise ratio" (MSNR) based on signal-to-noise in order to be more reasonable to evaluate frame accumulated medical image quality. We demonstrate its potential application through a series of images under a constant illumination signal. Here, the mean image of enough images was regarded as the reference image. Several groups of images by different frame accumulation and their MSNR were calculated. The results of the experiment show that, compared with other quality assessment methods, the metric is simpler, more effective, and more suitable for assessing frame accumulated images that surpass the gray scale and precision of the original image.

  3. Visualization rhetoric: framing effects in narrative visualization.

    Science.gov (United States)

    Hullman, Jessica; Diakopoulos, Nicholas

    2011-12-01

    Narrative visualizations combine conventions of communicative and exploratory information visualization to convey an intended story. We demonstrate visualization rhetoric as an analytical framework for understanding how design techniques that prioritize particular interpretations in visualizations that "tell a story" can significantly affect end-user interpretation. We draw a parallel between narrative visualization interpretation and evidence from framing studies in political messaging, decision-making, and literary studies. Devices for understanding the rhetorical nature of narrative information visualizations are presented, informed by the rigorous application of concepts from critical theory, semiotics, journalism, and political theory. We draw attention to how design tactics represent additions or omissions of information at various levels-the data, visual representation, textual annotations, and interactivity-and how visualizations denote and connote phenomena with reference to unstated viewing conventions and codes. Classes of rhetorical techniques identified via a systematic analysis of recent narrative visualizations are presented, and characterized according to their rhetorical contribution to the visualization. We describe how designers and researchers can benefit from the potentially positive aspects of visualization rhetoric in designing engaging, layered narrative visualizations and how our framework can shed light on how a visualization design prioritizes specific interpretations. We identify areas where future inquiry into visualization rhetoric can improve understanding of visualization interpretation. © 2011 IEEE

  4. On the role of covariance information for GRACE K-band observations in the Celestial Mechanics Approach

    Science.gov (United States)

    Bentel, Katrin; Meyer, Ulrich; Arnold, Daniel; Jean, Yoomin; Jäggi, Adrian

    2017-04-01

    The Astronomical Institute at the University of Bern (AIUB) derives static and time-variable gravity fields by means of the Celestial Mechanics Approach (CMA) from GRACE (level 1B) data. This approach makes use of the close link between orbit and gravity field determination. GPS-derived kinematic GRACE orbit positions, inter-satellite K-band observations, which are the core observations of GRACE, and accelerometer data are combined to rigorously estimate orbit and spherical harmonic gravity field coefficients in one adjustment step. Pseudo-stochastic orbit parameters are set up to absorb unmodeled noise. The K-band range measurements in along-track direction lead to a much higher correlation of the observations in this direction compared to the other directions and thus, to north-south stripes in the unconstrained gravity field solutions, so-called correlated errors. By using a full covariance matrix for the K-band observations the correlation can be taken into account. One possibility is to derive correlation information from post-processing K-band residuals. This is then used in a second iteration step to derive an improved gravity field solution. We study the effects of pre-defined covariance matrices and residual-derived covariance matrices on the final gravity field product with the CMA.

  5. Frame to Frame Diffeomorphic Motion Analysis from Echocardiographic Sequences

    OpenAIRE

    Zhang, Zhijun; Sahn, David; Song, Xubo

    2011-01-01

    International audience; Quantitative motion analysis from echocardiography is an important yet challenging problem. We develop a motion estimation algorithm for echocardiographic image sequences based on diffeomorphic image registration in which the velocity field is spatiotemporally smooth. The novelty of this work is that instead of optimizing a functional of velocity field which consists of similarity metrics between a reference image to each of the following images (\\textitfirst-to-follow...

  6. Do framing effects reveal irrational choice?

    Science.gov (United States)

    Mandel, David R

    2014-06-01

    Framing effects have long been viewed as compelling evidence of irrationality in human decision making, yet that view rests on the questionable assumption that numeric quantifiers used to convey the expected values of choice options are uniformly interpreted as exact values. Two experiments show that when the exactness of such quantifiers is made explicit by the experimenter, framing effects vanish. However, when the same quantifiers are given a lower bound (at least) meaning, the typical framing effect is found. A 3rd experiment confirmed that most people spontaneously interpret the quantifiers in standard framing tests as lower bounded and that their interpretations strongly moderate the framing effect. Notably, in each experiment, a significant majority of participants made rational choices, either choosing the option that maximized expected value (i.e., lives saved) or choosing consistently across frames when the options were of equal expected value. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  7. Frames in the Ethiopian Debate on Biofuels

    Directory of Open Access Journals (Sweden)

    Brigitte Portner

    2013-01-01

    Full Text Available Biofuel production, while highly contested, is supported by a number of policies worldwide. Ethiopia was among the first sub-Saharan countries to devise a biofuel policy strategy to guide the associated demand toward sustainable development. In this paper, I discuss Ethiopia’s biofuel policy from an interpretative research position using a frames approach and argue that useful insights can be obtained by paying more attention to national contexts and values represented in the debates on whether biofuel production can or will contribute to sustainable development. To this end, I was able to distinguish three major frames used in the Ethiopian debate on biofuels: an environmental rehabilitation frame, a green revolution frame and a legitimacy frame. The article concludes that actors advocating for frames related to social and human issues have difficulties entering the debate and forming alliances, and that those voices need to be included in order for Ethiopia to develop a sustainable biofuel sector.

  8. Nonlinear approximation with nonstationary Gabor frames

    DEFF Research Database (Denmark)

    Ottosen, Emil Solsbæk; Nielsen, Morten

    2018-01-01

    We consider sparseness properties of adaptive time-frequency representations obtained using nonstationary Gabor frames (NSGFs). NSGFs generalize classical Gabor frames by allowing for adaptivity in either time or frequency. It is known that the concept of painless nonorthogonal expansions...... resolution. Based on this characterization we prove an upper bound on the approximation error occurring when thresholding the coefficients of the corresponding frame expansions. We complement the theoretical results with numerical experiments, estimating the rate of approximation obtained from thresholding...

  9. A Formal Description of Problem Frames

    OpenAIRE

    Souleymane KOUSSOUBE; Roger NOUSSI; Balira O. KONFE

    2014-01-01

    Michael Jackson defines a Problem Frame as a mean to describe and classify software development problems. The initial description of problem Frames is essentially graphical. A weakness of this proposal is the lack of formal specification allowing efficient reasoning tools. This paper deals with Problem Frames’ formal specification with Description Logics. We first propose a formal terminology of Problem Frames leading to the specification of a Problem Frames’ TBOX and a specific problem’s ABO...

  10. Supporting Product Line Evolution with Framed Aspects

    DEFF Research Database (Denmark)

    Loughran, Neil; Rashid, Awais; Zhang, Weishan

    2004-01-01

    This paper discusses how evolution in software product lines can be supported using framed aspects: a combination of aspect-oriented programming and frame technology. Product line architectures and assets are subject to maintenance and evolution throughout their lifetime due to the emergence of new...... of both technologies in combination. The amalgamation of framing and aspect-oriented techniques can help in the integration of new features and thus reduce the risk of architectural erosion....

  11. FRAME, animal experimentation and the Three Rs: past, present and future.

    Science.gov (United States)

    Balls, Michael

    2009-12-01

    At the opening of a meeting to celebrate the 50th anniversary of the publication of The Principles of Humane Experimental Technique, by W.M.S. Russell and R.L. Burch, and the 40th anniversary of the establishment of FRAME, some comments on the early days of the Charity are made, with particular reference to the special contributions made by its founder-Chairman, Dorothy Hegarty, and the author's own appointment as a Trustee, and later as Chairman. Reference is made to some key events and successes, and especially to the importance of FRAME's move from London to Nottingham, and the establishment of an ongoing collaboration with the University of Nottingham, including the setting-up of the FRAME Alternatives Laboratory. 2009 FRAME.

  12. Immune reactivity of candidate reference materials

    NARCIS (Netherlands)

    Fernandez-Rivas, Montserrat; Aalbers, Marja; Fötisch, Kay; de Heer, Pleuni; Notten, Silla; Vieths, Stefan; van Ree, Ronald

    2006-01-01

    Immune reactivity is a key issue in the evaluation of the quality of recombinant allergens as potential reference materials. Within the frame of the CREATE project, the immune reactivity of the natural and recombinant versions of the major allergens of birch pollen (Bet v 1), grass pollen (Phl p 1

  13. Morphogenesis of Kinetic Reciprocal Frames

    DEFF Research Database (Denmark)

    Parigi, Dario; Sassone, Mario

    2011-01-01

    Kinetic structures in civil engineering and architecture gained considerable more attention in the very recent years as a practical solution to face time dependant performances. Realized projects are mostly bridges, retractable roofs, while in architecture the trend follows the category of intera......Kinetic structures in civil engineering and architecture gained considerable more attention in the very recent years as a practical solution to face time dependant performances. Realized projects are mostly bridges, retractable roofs, while in architecture the trend follows the category...... (RF) were studied in the past as a practical solution to span distances with shorter elements. Leonardo da Vinci discovered interesting RF patterns and studied three dimensional arch structures for bridges. RF are generally defined as structures that forms closed circuits of forces, and where elements...... joins in intermediate points. In the present paper we will describe a new subset of kinetic structures based on reciprocal frames topology and pin-slot constraint, a connection where a pin is constrained to move along a slot, and to rotate around its axis. The first step in obtaining a kinetic...

  14. Weather Test Reference Year of Greenland

    DEFF Research Database (Denmark)

    Kragh, Jesper; Pedersen, Frank; Svendsen, Svend

    2005-01-01

    the construction of two test reference years of Greenland used in the work of establishing new energy frame for the coming building code of Greenland. The first test reference year is constructed using measurements of climatic parameters from the town Nuuk located in the southwestern part of Greenland. The second...... test reference year is constructed using measurements from the town Uummannaq located in the north part of Greenland on the west coast. The construction of the test reference years fulfills the procedures described in the standard EN ISO 15927-4 using the following main weather parameters: Dry bulb...... temperature, global radiation, relative humidity and mean wind speed. To construct the test reference years a program called REFYEAR was developed in MatLab. REFYEAR automatically constructs the test reference year using an input file containing the climatic measurements. The two constructed test reference...

  15. Parameter subset selection based damage detection of aluminium frame structure

    International Nuclear Information System (INIS)

    Titurus, B; Friswell, M I

    2011-01-01

    A three storey aluminium frame structure was tested in multiple damage cases. All damage scenarios, simulated by the localized stiffness changes, were associated with joint areas of the structure. Further, between damage tests the structure was returned to its healthy reference conditions and was again measured. In this paper, a parameter subset selection methodology is applied to an updated finite element model of the structure, together with a previously demonstrated approach employing concepts of model sensitivity subspace angles, first order model representation and mixed response residuals for damage detection. The objective of this paper is the evaluation of these methods on a real experimental structure with significant complexity, represented by an imprecise reference mathematical model and in the environment with uncertain reference structural state. The questions of symmetry, mixed response residuals and semi-localized parameterization are also addressed in this work.

  16. Network-based H.264/AVC whole frame loss visibility model and frame dropping methods.

    Science.gov (United States)

    Chang, Yueh-Lun; Lin, Ting-Lan; Cosman, Pamela C

    2012-08-01

    We examine the visual effect of whole frame loss by different decoders. Whole frame losses are introduced in H.264/AVC compressed videos which are then decoded by two different decoders with different common concealment effects: frame copy and frame interpolation. The videos are seen by human observers who respond to each glitch they spot. We found that about 39% of whole frame losses of B frames are not observed by any of the subjects, and over 58% of the B frame losses are observed by 20% or fewer of the subjects. Using simple predictive features which can be calculated inside a network node with no access to the original video and no pixel level reconstruction of the frame, we developed models which can predict the visibility of whole B frame losses. The models are then used in a router to predict the visual impact of a frame loss and perform intelligent frame dropping to relieve network congestion. Dropping frames based on their visual scores proves superior to random dropping of B frames.

  17. Update on Pluto and Its 5 Moons Obeying the Quantization of Angular Momentum per Unit Mass Constraint of Quantum Celestial Mechanics

    Directory of Open Access Journals (Sweden)

    Potter F.

    2016-01-01

    Full Text Available In July, 2015, the New Horizons spacecraft passing by Pluto did not discover any more moons. Therefore, we know the Pluto system total angular momentum to within 2.4%, more accurately than any other system with more than two orbiting bodies. We there- fore update our previous analysis to determine whether a definitive test of the quantum celestial mechanics (QCM angular momentum constraint can now be achieved.

  18. Moving frames for heart fiber geometry

    DEFF Research Database (Denmark)

    Piuze, Emmanuel; Sporring, Jon; Siddiqi, Kaleem

    2013-01-01

    frames to study the rotations of a frame field attached to the local fiber direction. This approach provides a new set of parameters that are complimentary to those of Savadjiev et al. and offers a framework for developing new models of the cardiac fiber architecture. This framework is used to compute...

  19. Time-framing and health risks: editorial

    NARCIS (Netherlands)

    Brown, P.; Heyman, B.; Alaszewski, A.

    2013-01-01

    This special issue is the last in a four-part series Health Care Through the ‘Lens of Risk’, which focuses on risk categorisation, valuing, expecting and time-framing, respectively, and has been published in 2012-2013. The present editorial introduces the issue of time-framing in relation to an

  20. Framing Behaviours in Novice Interaction Designers

    Science.gov (United States)

    Lotz, Nicole; Sharp, Helen; Woodroffe, Mark; Blyth, Richard; Rajah, Dino; Ranganai, Turugare

    2015-01-01

    Framing design problems and solutions has been recognised in design studies as a central designerly activity. Some recent findings with expert designers relate framing practices to problem-solution co-evolution and analogy use, two further widely recognised design strategies. We wanted to understand if interaction design novices also use…