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Sample records for celestial reference frame

  1. Connecting VLBI and Gaia celestial reference frames

    CERN Document Server

    Malkin, Zinovy

    2016-01-01

    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 comparison and the mutual orientation and rotation between the optical {\\it Gaia} Celestial Reference Frame (GCRF) and 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 task due 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 s...

  2. 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.

  3. The ICRF-3: Status, plans, and progress on the next generation International Celestial Reference Frame

    CERN Document Server

    Malkin, Z; Arias, F; Boboltz, D; Boehm, J; Bolotin, S; Bourda, G; Charlot, P; De Witt, A; Fey, A; Gaume, R; Heinkelmann, R; Lambert, S; Ma, C; Nothnagel, A; Seitz, M; Gordon, D; Skurikhina, E; Souchay, J; Titov, O

    2015-01-01

    The goal of this presentation is to report the latest progress in creation of the next generation of VLBI-based International Celestial Reference Frame, ICRF3. Two main directions of ICRF3 development are improvement of the S/X-band frame and extension of the ICRF to higher frequencies. Another important task of this work is the preparation for comparison of ICRF3 with the new generation optical frame GCRF expected by the end of the decade as a result of the Gaia mission.

  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. E.; García-Miró, C.; Horiuchi, S.; Sotuela, I.

    2011-10-01

    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 ~200 micro-arcsec (μas) in α cos δ and ~300 μas in δ. There is evidence for systematic errors at the 100 μas 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. 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.

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

    Institute of Scientific and Technical Information of China (English)

    Nicole Capitaine

    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 improvements in the fields

  8. On the consistency of the current conventional EOP series and the celestial and terrestrial reference frames

    Science.gov (United States)

    Belda, Santiago; Heinkelmann, Robert; Ferrándiz, José M.; Nilsson, Tobias; Schuh, Harald

    2017-02-01

    Precise transformation between the celestial reference frames (CRF) and terrestrial reference frames (TRF) is needed for many purposes in Earth and space sciences. According to the Global Geodetic Observing System (GGOS) recommendations, the accuracy of positions and stability of reference frames should reach 1 mm and 0.1 mm year^{-1}, and thus, the Earth Orientation Parameters (EOP) should be estimated with similar accuracy. Different realizations of TRFs, based on the combination of solutions from four different space geodetic techniques, and CRFs, based on a single technique only (VLBI, Very Long Baseline Interferometry), might cause a slow degradation of the consistency among EOP, CRFs, and TRFs (e.g., because of differences in geometry, orientation and scale) and a misalignment of the current conventional EOP series, IERS 08 C04. We empirically assess the consistency among the conventional reference frames and EOP by analyzing the record of VLBI sessions since 1990 with varied settings to reflect the impact of changing frames or other processing strategies on the EOP estimates. Our tests show that the EOP estimates are insensitive to CRF changes, but sensitive to TRF variations and unmodeled geophysical signals at the GGOS level. The differences between the conventional IERS 08 C04 and other EOP series computed with distinct TRF settings exhibit biases and even non-negligible trends in the cases where no differential rotations should appear, e.g., a drift of about 20 μ as year^{-1 }in y_{pol } when the VLBI-only frame VTRF2008 is used. Likewise, different strategies on station position modeling originate scatters larger than 150 μ as in the terrestrial pole coordinates.

  9. On the consistency of the current conventional EOP series and the celestial and terrestrial reference frames

    Science.gov (United States)

    Belda, Santiago; Heinkelmann, Robert; Ferrándiz, José M.; Nilsson, Tobias; Schuh, Harald

    2016-08-01

    Precise transformation between the celestial reference frames (CRF) and terrestrial reference frames (TRF) is needed for many purposes in Earth and space sciences. According to the Global Geodetic Observing System (GGOS) recommendations, the accuracy of positions and stability of reference frames should reach 1 mm and 0.1 mm year^{-1} , and thus, the Earth Orientation Parameters (EOP) should be estimated with similar accuracy. Different realizations of TRFs, based on the combination of solutions from four different space geodetic techniques, and CRFs, based on a single technique only (VLBI, Very Long Baseline Interferometry), might cause a slow degradation of the consistency among EOP, CRFs, and TRFs (e.g., because of differences in geometry, orientation and scale) and a misalignment of the current conventional EOP series, IERS 08 C04. We empirically assess the consistency among the conventional reference frames and EOP by analyzing the record of VLBI sessions since 1990 with varied settings to reflect the impact of changing frames or other processing strategies on the EOP estimates. Our tests show that the EOP estimates are insensitive to CRF changes, but sensitive to TRF variations and unmodeled geophysical signals at the GGOS level. The differences between the conventional IERS 08 C04 and other EOP series computed with distinct TRF settings exhibit biases and even non-negligible trends in the cases where no differential rotations should appear, e.g., a drift of about 20 μ as year^{-1 } in y_{pol } when the VLBI-only frame VTRF2008 is used. Likewise, different strategies on station position modeling originate scatters larger than 150 μ as in the terrestrial pole coordinates.

  10. International Celestial Reference Frame (ICRF): mantenimiento y extensión

    Science.gov (United States)

    Ma, C.; Arias, E. F.; Eubanks, T.; Fey, A. L.; Gontier, A.-M.; Jacobs, C. S.; Sovers, O. J.; Archinal, B. A.; Charlot, P.

    A partir de enero de 1998 el sistema de referencia celeste convencional está representado por el International Celestial Reference System (ICRS) y materializado a través de las coordenadas VLBI del conjunto de radiofuentes extragalácticas que conforman el International Celestial Reference Frame (ICRF). La primera realización del ICRF, fue elaborada en 1995 por un grupo de expertos designado por la IAU, la que encomendó al International Earth Rotation Service el mantenimiento del ICRS, del ICRF y del vínculo con marcos de referencia en otras frecuencias. Una primera extensión del ICRF se realizó entre abril y junio de 1999, con el objetivo primario de proveer posiciones de radiofuentes extragalácticas observadas a partir de julio de 1995 y de mejorar las posiciones de las fuentes ``candidatas" con la inclusión de observaciones adicionales. Objetivos secundarios fueron monitorear a las radiofuentes para verificar que siguen siendo adecuadas para realizar al ICRF y mejorar las técnicas de análisis de datos. Como resultado del nuevo análisis se obtuvo una solución a partir de la cual se construyó la primera extensión del ICRF, denominada ICRF - Ext.1. Ella representa al ICRS, sus fuentes de definición se mantienen con las mismas posiciones y errores que en la primera realización del ICRF; las demás radiofuentes tienen coordenadas mejor determinadas que en ICRF; el marco de referencia se densificó con el agregado de 59 nuevas radiofuentes.

  11. The effects of frequency-dependent quasar evolution on the celestial reference frame

    CERN Document Server

    Shabala, Stanislav; McCallum, Jamie; Titov, Oleg; Blanchard, Jay; Lovell, Jim; Watson, Christopher

    2013-01-01

    We examine the relationship between source position stability and astrophysical properties of radio-loud quasars making up the International Celestial Reference Frame. We construct light curves for 95 most frequently observed ICRF2 quasars at both the geodetic VLBI observing bands. Because the appearance of new quasar components corresponds to an increase in quasar flux density, these light curves allow us to probe source structure on sub-100 microarcsecond scales, much smaller than conventional VLBI imaging. Flux density monitoring also allows us to trace the evolution of quasar structure. We test how source position stability depends on three astrophysical parameters: (1) Flux density variability at X-band; (2) Time lag between S and X-band light curves; (3) Spectral index rms, defined as the variability in the ratio between S and X-band flux densities. We find that small (<0.15 years) time lags between S and X-band light curves and low (<0.10) spectral index variability are excellent indicators of po...

  12. Non-linear VLBI station motions and their impact on the celestial reference frame and Earth orientation parameters.

    Science.gov (United States)

    Krásná, Hana; Malkin, Zinovy; Böhm, Johannes

    The increasing accuracy and growing time span of Very Long Baseline Interferometry (VLBI) observations allow the determination of seasonal signals in station positions which still remain unmodelled in conventional analysis approaches. In this study we focus on the impact of the neglected seasonal signals in the station displacement on the celestial reference frame and Earth orientation parameters. We estimate empirical harmonic models for selected stations within a global solution of all suitable VLBI sessions and create mean annual models by stacking yearly time series of station positions which are then entered a priori in the analysis of VLBI observations. Our results reveal that there is no systematic propagation of the seasonal signal into the orientation of celestial reference frame but position changes occur for radio sources observed non-evenly over the year. On the other hand, the omitted seasonal harmonic signal in horizontal station coordinates propagates directly into the Earth rotation parameters causing differences of several tens of microarcseconds.

  13. Sobre as Bases de Referência Celeste (On the Celestial Reference Frames)

    Science.gov (United States)

    Martin, Vera A. F.; Poppe, Paulo C. R.

    2003-05-01

    Ao longo deste artigo, apresentamos, como continuidade à discussão apresentada no trabalho anterior, uma primeira discussão sobre algumas das principais bases de referência utilizadas em Astronomia. Da mesma forma, esperamos que o presente texto possa ser utilizado ao longo dos cursos de Introdução à Astronomia das atuais graduações de Física e áreas afins.

  14. 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

  15. Optical variability and morphology of AGN. Consequences for the future Gaia Celestial Reference Frame.

    Science.gov (United States)

    Taris, François; Andrei, Alexandre; Anton, Sonia; Barache, Christophe; Coelho, Bruno; Klotz, Alain; Lambert, Sébastien; Souchay, Jean; Vachier, Frédéric

    2012-08-01

    The Gaia catalogue will contain 500 000 QSOs with very accurate optical coordinates, at level of some tens to some hundreds of micro - arcsecond. From these targets a core sample will be chosen, formed by those with the most precise positions, to define the Gaia Fundamental Reference Frame. It will be at the basis of an optical reference frame ( provisionally, the GCRF) more accurate than the current version of the (radio) ICRF. At the same time due care must be taken when choosing the core picks because quasars do are also known by their flux variability, on time scales that may span from hours u p to years. We will review some of the potential astrophysical processes that could induce these variations in the corresponding emission regions and we will present light curves that were obtained by small robotic telescopes during more than 1.5 years. We will also present high resolution images obtained at ground based optical telescopes together with the morphological analysis of the targets. Finally we will conclude by the presentation of an optical image database currently under construction in the frame of the ICRS - pc.

  16. New celestial reference system

    Science.gov (United States)

    Seidelmann, P. K.; Kaplan, G. H.; van Flandern, T. C.

    It is pointed out that the IAU (1976) System of Astronomical Constants, the FK5 and new lunar and planetary theories are being introduced in 1984. The investigation and planning for the transition have revealed the complex interdependencies between observational techniques and the reference systems and their strong link to the rotating and orbiting earth. Details for the conversion to the new system are given. The concepts for a future reference system are developed, based on separating the real motions involved in such a way that observations from various moving platforms can be related to the appropriate coordinate system without involving motions that are not intrinsically involved in the observations. As a consequence, the reference systems determined or used in space, while affected by aberration and parallax, would logically be defined with no dependence on precession, nutation, polar motion, or Universal Time, all of which are concerned with motions of the earth's surface.

  17. Long-term R and V-band monitoring of some suitable targets for the link between ICRF and the future Gaia celestial reference frame

    Science.gov (United States)

    Taris, F.; Andrei, A.; Roland, J.; Klotz, A.; Vachier, F.; Souchay, J.

    2016-03-01

    Context. The Gaia astrometric mission of the European Space Agency was launched on December 2013. It will provide a catalog of 500 000 quasars. Some of these targets will be chosen to build an optical reference system that will be linked to the International Celestial Reference Frame (ICRF). The astrometric coordinates of these sources will have roughly the same uncertainty at both optical and radio wavelengths, and it is then mandatory to observe a common set of targets to build the link. In the ICRF, some targets have been chosen because of their pointlikeness. They are quoted as defining sources, and they ensure very good uncertainty about their astrometric coordinates. At optical wavelengths, a comparable uncertainty could be achieved for targets that do not exhibit strong astrophysical phenomena, which is a potential source of photocenter flickering. A signature of these phenomena is a magnitude variation at optical wavelengths. Aims: The goal of this work is to present the time series of 14 targets suitable for the link between the ICRF and the future Gaia Celestial Reference Frame. The observations have been done systematically by robotic telescopes in France and Chile once every two nights since 2011 and in two filters. These time series are analyzed to search for periodic or quasi-periodic phenomena that must be taken into account when computing the uncertainty about the astrometric coordinates. Methods: Two independent methods were used in this work to analyze the time series. We used the CLEAN algorithm to compare the frequency obtained to those given by the Lomb-Scargle method. It avoids misinterpreting the frequency peaks given in the periodograms. Results: For the 14 targets we determine some periods with a confidence level above 90% in each case. Some of the periods found in this work were not previously known. For the others, we did a comparative study of the periods previously studied by others and always confirm their values. All the periods given

  18. Relativistic formulation and reference frame

    OpenAIRE

    Klioner, Sergei A.

    2004-01-01

    After a short review of experimental foundations of metric theories of gravity, the choice of general relativity as a theory to be used for the routine modeling of Gaia observations is justified. General principles of relativistic modeling of astronomical observations are then sketched and compared to the corresponding Newtonian principles. The fundamental reference system -- Barycentric Celestial Reference System, which has been chosen to be the relativistic reference system underlying the f...

  19. Using radio stars to link ICRF and GCRF reference frames

    CERN Document Server

    Malkin, Zinovy

    2016-01-01

    One of the possible strategies for linking the optical Gaia Celestial Reference Frame (GCRF) to the VLBI-based International Celestial Reference Frame (ICRF) is using radio stars in a manner similar to that used for linking HIPPARCOS Celestial Reference System (HCRF) to ICRF. A reachable precision of the orientation angles between GCRF and ICRF frames was estimated through Monte Carlo simulation. Supposing the radio stars position uncertainty obtained by VLBI in the range of 0.1 to 4 mas, and Gaia position uncertainty in the range of 0.055 to 0.4 mas, depending in the first place on the brightness of radio star in radio and optics and number of VLBI observations, the orientation angles uncertainty will be 0.02 to 0.66 mas for 46 radio stars used, and 0.01 to 0.39 mas for 138 radio stars used. Properly organized VLBI observing program on radio stars observations can allow to tie GCRF to ICRF with the accuracy better than 0.1 mas.

  20. Reference frame for Product Configuration

    DEFF Research Database (Denmark)

    Ladeby, Klaes Rohde; Oddsson, Gudmundur Valur

    2011-01-01

    on configuration systems in the shape of anecdotal reporting on the development of information systems that perhaps support the configuration task – perhaps not. Consequently, the definition of configuration has become ambiguous as different research groups defines configuration differently. This paper propose...... a reference frame for configuration that permits 1) a more precise understanding of a configuration system, 2) a understanding of how the configuration system relate to other systems, and 3) a definition of the basic concepts in configuration. The total configuration system, together with the definition...

  1. Common Frame of Reference and social justice

    NARCIS (Netherlands)

    Hesselink, M.W.; Satyanarayana, R.

    2009-01-01

    The article "Common Frame of Reference and Social Justice" by Martijn W. Hesselink evaluates the Draft Common Frame of Reference (DCFR) of social justice. It discusses the important areas, namely a common frame of Reference in a broad sense, social justice and contract law, private law and democracy

  2. Frames of Reference in the Classroom

    Science.gov (United States)

    Grossman, Joshua

    2012-01-01

    The classic film "Frames of Reference" effectively illustrates concepts involved with inertial and non-inertial reference frames. In it, Donald G. Ivey and Patterson Hume use the cameras perspective to allow the viewer to see motion in reference frames translating with a constant velocity, translating while accelerating, and rotating--all with…

  3. 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…

  4. Visual performance fields: frames of reference.

    Science.gov (United States)

    Corbett, Jennifer E; Carrasco, Marisa

    2011-01-01

    Performance in most visual discrimination tasks is better along the horizontal than the vertical meridian (Horizontal-Vertical Anisotropy, HVA), and along the lower than the upper vertical meridian (Vertical Meridian Asymmetry, VMA), with intermediate performance at intercardinal locations. As these inhomogeneities are prevalent throughout visual tasks, it is important to understand the perceptual consequences of dissociating spatial reference frames. In all studies of performance fields so far, allocentric environmental references and egocentric observer reference frames were aligned. Here we quantified the effects of manipulating head-centric and retinotopic coordinates on the shape of visual performance fields. When observers viewed briefly presented radial arrays of Gabors and discriminated the tilt of a target relative to homogeneously oriented distractors, performance fields shifted with head tilt (Experiment 1), and fixation (Experiment 2). These results show that performance fields shift in-line with egocentric referents, corresponding to the retinal location of the stimulus.

  5. Quantum hydrodynamics in the rotating reference frame

    CERN Document Server

    Trukhanova, Mariya Iv

    2016-01-01

    In this paper we apply quantum hydrodynamics (QHD) to study the quantum evolution of a system of spinning particles and particles that have the electric dipole moments EDM in the rotating reference frame. The method presented is based on the many-particle microscopic Schrodinger equation in the rotating reference frame. Fundamental QHD equations for charged or neutral spinning and EDM-bearing particles were shaped due to this method and contain the spin-dependent inertial force field. The polarization dynamics in systems of neutral particles in the rotating frame is shown to cause formation of a new type of waves, the dipole-inertial waves. We have analyzed elementary excitations in a system of neutral polarized fluids placed into an external electric field in 2D and 3D cases. We predict the novel type of 2D dipole-inertial wave and 3D - polarization wave modified by rotation in systems of particles with dipole-dipole interactions.

  6. Frames of Reference in the Classroom

    Science.gov (United States)

    Grossman, Joshua

    2012-12-01

    The classic film "Frames of Reference"1,2 effectively illustrates concepts involved with inertial and non-inertial reference frames. In it, Donald G. Ivey and Patterson Hume use the cameras perspective to allow the viewer to see motion in reference frames translating with a constant velocity, translating while accelerating, and rotating—all with respect to the Earth frame. The film is a classic for good reason, but today it does have a couple of drawbacks: 1) The film by nature only accommodates passive learning. It does not give students the opportunity to try any of the experiments themselves. 2) The dated style of the 50-year-old film can distract students from the physics content. I present here a simple setup that can recreate many of the movies demonstrations in the classroom. The demonstrations can be used to supplement the movie or in its place, if desired. All of the materials except perhaps the inexpensive web camera should likely be available already in most teaching laboratories. Unlike previously described activities, these experiments do not require travel to another location3 or an involved setup.4,5

  7. The Gaia reference frame amid quasar variability and proper motion patterns in the data

    CERN Document Server

    Bachchan, R K; Lindegren, L

    2015-01-01

    Gaia's very accurate astrometric measurements will allow the International Celestial Reference Frame (ICRF) to be improved by a few orders of magnitude in the optical. Several sets of quasars are used to define a kinematically stable non-rotating reference frame with the barycentre of the Solar System as its origin. Gaia will also observe a large number of galaxies which could obtain accurate positions and proper motions although they are not point-like. The optical stability of the quasars is critical and we investigate how accurately the reference frame can be recovered. Various proper motion patterns are also present in the data, the best known is caused by the acceleration of the Solar System Barycentre, presumably, towards the Galactic centre. We review some other less-well-known effects that are not part of standard astrometric models. We model quasars and galaxies using realistic sky distributions, magnitudes and redshifts. Position variability is introduced using a Markov chain model. The reference fr...

  8. An Autonomous Reference Frame for Relativistic GNSS

    CERN Document Server

    Kostić, Uroš; Carloni, Sante; Delva, Pacôme; Gomboc, Andreja

    2014-01-01

    Current GNSS systems rely on global reference frames which are fixed to the Earth (via the ground stations) so their precision and stability in time are limited by our knowledge of the Earth dynamics. These drawbacks could be avoided by giving to the constellation of satellites the possibility of constituting by itself a primary and autonomous positioning system, without any a priori realization of a terrestrial reference frame. Our work shows that it is possible to construct such a system, an Autonomous Basis of Coordinates, via emission coordinates. Here we present the idea of the Autonomous Basis of Coordinates and its implementation in the perturbed space-time of Earth, where the motion of satellites, light propagation, and gravitational perturbations are treated in the formalism of general relativity.

  9. Aligning Reference Frames Using Quantum States

    CERN Document Server

    Bagán, E; Muñoz-Tàpia, R

    2001-01-01

    We analyze the problem of sending, in a single transmission, the information required to specify an orthogonal trihedron or reference frame through a quantum channel made out of N elementary spins. We analytically obtain the optimal strategy, i.e., the best encoding state and the best measurement. For large N, we show that the average error goes to zero linearly in 1/N. Finally, we discus the construction of finite optimal measurements.

  10. 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.

  11. Gaia Reference frame determination: the AVU/GSR pipeline

    Science.gov (United States)

    Vecchiato, Alberto; Abbas, Ummi; Becciani, Ugo; Bianchi, Luca; Bucciarelli, Beatrice; Crosta, Mariateresa; Lattanzi, Mario G.

    2015-08-01

    The main goal of the Gaia ESA mission is the production of a 5 parameters astrometric catalog - i.e. including positions, parallaxes and the two components of the proper motions - of about 1 billion stars of our Galaxy at an accuracy level going from the few micro-arcseconds of the brightest objects to some ~100 micro-arcseconds of the faintests. This goal will be reached by means of high-precision astrometric measurements conducted by a satellite sweeping continuously the celestial sphere during its 5-years mission.A fundamental step toward the realization of this catalog is the so-called ''Sphere Reconstruction'', which determines the celestial reference frame using the observations of a subset of up to 100 million ''primary stars'' among those observed by Gaia.From a mathematical point of view, these observations translate into a large number of equations, linearized with respect to the unknown parameters around known initial values, whose solution in the least-squares sense eventually provides the catalog with its errors, and determines the Gaia reference frame.This represents an extremely challenging problem because of the high accuracy of the observations and of the large number of unknowns involved. The former issue implies that an adequately accurate relativistic astrometric model has to be used, while the huge number of unknowns and observations puts this task at the forefront of the High-Performance Computing problems.These challenges, and the absolute character of the Gaia measurements and results, calls for a careful scientific validation of the sphere reconstruction, as it was done for the previous HIPPARCOS mission. For these reasons the Gaia Data Processing and Analysis Consortium (DPAC) decided to replicate the baseline process, named AGIS (Astrometric Global Iterative Solution) with another independent solution, named GSR (Global Sphere Reconstruction) which uses a different astrometric model and different algorithms for the system solution

  12. Postural adaptation of the spatial reference frames to microgravity: back to the egocentric reference frame.

    Directory of Open Access Journals (Sweden)

    Sébastien Viel

    Full Text Available BACKGROUND: In order to test how gravitational information would affect the choice of stable reference frame used to control posture and voluntary movement, we have analysed the forearm stabilisation during sit to stand movement under microgravity condition obtained during parabolic flights. In this study, we hypothesised that in response to the transient loss of graviceptive information, the postural adaptation might involve the use of several strategies of segmental stabilisation, depending on the subject's perceptual typology (dependence--independence with respect to the visual field. More precisely, we expected a continuum of postural strategies across subjects with 1 at one extreme the maintaining of an egocentric reference frame and 2 at the other the re-activation of childhood strategies consisting in adopting an egocentric reference frame. METHODOLOGY/PRINCIPAL FINDINGS: To check this point, a forearm stabilisation task combined with a sit to stand movement was performed with eyes closed by 11 subjects during parabolic flight campaigns. Kinematic data were collected during 1-g and 0-g periods. The postural adaptation to microgravity's constraint may be described as a continuum of strategies ranging from the use of an exo- to an egocentric reference frame for segmental stabilisation. At one extremity, the subjects used systematically an exocentric frame to control each of their body segments independently, as under normogravity conditions. At the other, the segmental stabilisation strategies consist in systematically adopting an egocentric reference frame to control their forearm's stabilisation. A strong correlation between the mode of segmental stabilisation used and the perceptual typology (dependence--independence with respect to the visual field of the subjects was reported. CONCLUSION: The results of this study show different subjects' typologies from those that use the forearm orientation in a mainly exocentric reference frame to

  13. Reference frame independent quantum key distribution

    CERN Document Server

    Laing, Anthony; Rarity, John G; O'Brien, Jeremy L

    2010-01-01

    We describe a quantum key distribution protocol based on pairs of entangled qubits that generates a secure key between two partners in an environment of unknown and slowly varying reference frame. A direction of particle delivery is required, but the phases between the computational basis states need not be known or fixed. The protocol can simplify the operation of existing setups and has immediate applications to emerging scenarios such as earth-to-satellite links and the use of integrated photonic waveguides. We compute the asymptotic secret key rate for a two-qubit source, which coincides with the rate of the six-state protocol for white noise. We give the generalization of the protocol to higher-dimensional systems and detail a scheme for physical implementation in the three dimensional qutrit case.

  14. The Michelson-Morley experiment in an accelerated reference frame

    CERN Document Server

    Crossley, Dennis

    2010-01-01

    We analyze the Michelson-Morley experiment in a reference frame moving with constant proper acceleration. Interestingly, we find an expected fringe shift which depends not only on the interferometer's rate of acceleration, but also on its speed relative to a preferred absolute reference frame. While it has been repeatedly shown that no experiment performed in an inertial reference frame can detect that frame's absolute speed, the analysis in this paper suggests that by considering experiments in accelerated reference frames it may be possible to measure absolute speed after all.

  15. Theory of Relativistic Reference Frames for High-Precision Astrometric Space Missions

    CERN Document Server

    Kopeikin, S M

    2000-01-01

    Recent modern space missions deliver invaluable information about origin of our universe, physical processes in the vicinity of black holes and other exotic astrophysical objects, stellar dynamics of our galaxy, etc. On the other hand, space astrometric missions make it possible to determine with unparalleled precision distances to stars and cosmological objects as well as their physical characteristics and positions on the celestial sphere. Permanently growing accuracy of space astronomical observations and the urgent need for adequate data processing algorithms require corresponding development of an adequate theory of reference frames along with unambiguous description of propagation of light rays from a source of light to observer. Such a theory must be based on the Einstein's general relativity and account for numerous relativistic effects both in the solar system and outside of its boundary. The main features of the relativistic theory of reference frames are presented in this work. A hierarchy of the f...

  16. The Dirac oscillator in a rotating frame of reference

    Science.gov (United States)

    Strange, P.; Ryder, L. H.

    2016-10-01

    The Dirac equation in a rotating frame of reference is derived from first principles within a linear approximation. This equation is employed to exhibit an equivalence between a particle in a Dirac oscillator potential and a free particle in a rotating frame of reference. A zero-point contribution to the energy of the particle, resulting from its spin, is also noted.

  17. Dynamics of a Quantum Reference Frame

    CERN Document Server

    Poulin, D; Poulin, David; Yard, Jon

    2006-01-01

    We analyze a quantum mechanical gyroscope, which is modeled as a large spin and used as a reference against which to measure the angular momenta of spin-1/2 particles. These measurements induce a back-action on the reference which is the central focus of our study. We begin by deriving explicit expressions for the quantum channel representing the back-action. Then, we analyze the dynamics incurred by the reference when it is used to sequentially measure particles drawn from a fixed ensemble. We prove that the reference thermalizes with the measured particles and find that generically, the thermal state is reached in time which scales linearly with the size of the reference. This contrasts a recent conclusion of Bartlett et al. that this takes a quadratic amount of time when the particles are completely unpolarized. We now understand their result in terms of a simple physical principle based on symmetries and conservation laws. Finally, we initiate the study of the non-equilibrium dynamics of the reference. He...

  18. Future National Reference Frames for the United States

    Science.gov (United States)

    Stone, W. A.

    2015-12-01

    The mission of the National Oceanic and Atmospheric Administration's National Geodetic Survey (NGS) is "to define, maintain and provide access to the National Spatial Reference System (NSRS) to meet our nation's economic, social, and environmental needs." NSRS is the nation's system of latitude, longitude, elevation, and related geophysical and geodetic models and tools, which provides a consistent spatial reference framework for the broad spectrum of geoscientific applications and other positioning-related requirements. Technological developments - notably Global Navigation Satellite Systems (GNSS) - and user accuracy requirements necessitate that NGS endeavor to modernize the NSRS. Preparations are underway by NGS for a comprehensive NSRS makeover, to be completed in 2022 and delivered through a new generation of horizontal and vertical datums (reference frames), featuring unprecedented accuracy, repeatability, and efficiency of access. This evolution is outlined in the "National Geodetic Survey Ten-Year Strategic Plan, 2013-2023." This presentation will outline the motivation for this effort and the history, current status and planned evolution of NSRS. Fundamental to the delivery of the future reference frame paradigm are new geometric and geopotential (elevation) frameworks. The new geometric reference frame, realized through GNSS Continuously Operating Reference Stations (CORS), will replace the North American Datum of 1983 (NAD83) and will provide the nationwide framework for determination of latitude, longitude, and ellipsoid height. Designed to complement the new geometric reference frame, a corresponding geopotential reference frame - based on a national gravimetric geoid and replacing the North American Vertical Datum of 1988 (NAVD88) - will be developed and co-released. The gravimetric geoid - or definitional reference surface (zero elevation) - for the future geopotential reference frame will be built in part from airborne gravimetric data collected in

  19. Newton-Cartan Gravity in Noninertial Reference Frames

    CERN Document Server

    Rodriguez, Leo; Wickramasekara, Sujeev

    2014-01-01

    We study properties of Newton-Cartan gravity under transformations into all noninertial, nonrelativistic reference frames. The set of these transformations has the structure of an infinite dimensional Lie group, called the Galilean line group, which contains as a subgroup the Galilei group. We show that the fictitious forces of noninertial reference frames are naturally encoded in the Cartan connection transformed under the Galilean line group. These noninertial forces, which are coordinate effects, do not contribute to the Ricci tensor which describes the curvature of Newtonian spacetime. We show that only the $00$-component of the Ricci tensor is non-zero and equal to ($4\\pi$ times) the matter density in any inertial or noninetial reference frame and that it leads to what may be called Newtonian ADM mass. While the Ricci field equation and Gauss law are both fulfilled by the same physical matter density in inertial and linearly accelerating reference frames, there appears a discrepancy between the two in ro...

  20. Public-key cryptography based on bounded quantum reference frames

    OpenAIRE

    Ioannou, Lawrence M.; Mosca, Michele

    2009-01-01

    We demonstrate that the framework of bounded quantum reference frames has application to building quantum-public-key cryptographic protocols and proving their security. Thus, the framework we introduce can be seen as a public-key analogue of the framework of Bartlett et al. (Phys. Rev. A 70, 032307), where a private shared reference frame is shown to have cryptographic application. The protocol we present in this paper is an identification scheme, which, like a digital signature scheme, is a ...

  1. Reference frames in virtual spatial navigation are viewpoint dependent

    Directory of Open Access Journals (Sweden)

    Ágoston eTörök

    2014-09-01

    Full Text Available Spatial navigation in the mammalian brain relies on a cognitive map of the environment. Such cognitive maps enable us, for example, to take the optimal route from a given location to a known target. The formation of these maps is naturally influenced by our perception of the environment, meaning it is dependent on factors such as our viewpoint and choice of reference frame. Yet, it is unknown how these factors influence the construction of cognitive maps. Here, we evaluated how various combinations of viewpoints and reference frames affect subjects’ performance when they navigated in a bounded virtual environment without landmarks. We measured both their path length and time efficiency and found that (i ground perspective was associated with egocentric frame of reference, (ii aerial perspective was associated with allocentric frame of reference, (iii there was no appreciable performance difference between first and third person egocentric viewing positions and (iv while none of these effects were dependent on gender, males tended to perform better in general. Our study provides evidence that there are inherent associations between visual perspectives and cognitive reference frames. This result has implications about the mechanisms of path integration in the human brain and may also inspire designs of virtual reality applications. Lastly, we demonstrated the effective use of a tablet PC and spatial navigation tasks for studying spatial and cognitive aspects of human memory.

  2. Asynchronous reference frame agreement in a quantum network

    Science.gov (United States)

    Islam, Tanvirul; Wehner, Stephanie

    2016-03-01

    An efficient implementation of many multiparty protocols for quantum networks requires that all the nodes in the network share a common reference frame. Establishing such a reference frame from scratch is especially challenging in an asynchronous network where network links might have arbitrary delays and the nodes do not share synchronised clocks. In this work, we study the problem of establishing a common reference frame in an asynchronous network of n nodes of which at most t are affected by arbitrary unknown error, and the identities of the faulty nodes are not known. We present a protocol that allows all the correctly functioning nodes to agree on a common reference frame as long as the network graph is complete and not more than t\\lt n/4 nodes are faulty. As the protocol is asynchronous, it can be used with some assumptions to synchronise clocks over a network. Also, the protocol has the appealing property that it allows any existing two-node asynchronous protocol for reference frame agreement to be lifted to a robust protocol for an asynchronous quantum network.

  3. Jerk and Hyperjerk in a Rotating Frame of Reference

    CERN Document Server

    Sparavigna, Amelia Carolina

    2015-01-01

    Jerk is the derivative of acceleration with respect to time and then it is the third order derivative of the position vector. Hyperjerks are the n-th order derivatives with n>3. This paper describes the relations, for jerks and hyperjerks, between the quantities measured in an inertial frame of reference and those observed in a rotating frame. These relations can be interesting for teaching purposes.

  4. Relativistic quantum information theory and quantum reference frames

    CERN Document Server

    Palmer, Matthew C

    2013-01-01

    This thesis is a compilation of research in relativistic quantum information theory, and research in quantum reference frames. The research in the former category provides a fundamental construction of quantum information theory of localised qubits in curved spacetimes. For example, this concerns quantum experiments on free-space photons and electrons in the vicinity of the Earth. From field theory a description of localised qubits that traverse classical trajectories in curved spacetimes is obtained, for photons and massive spin-1/2 fermions. The equations governing the evolution of the two-dimensional quantum state and its absolute phase are determined. Quantum information theory of these qubits is then developed. The Stern-Gerlach measurement formalism for massive spin-1/2 fermions is also derived from field theory. In the latter category of research, the process of changing reference frames is considered for the case where the reference frames are quantum systems. As part of this process, it is shown that...

  5. Visual Target Localization, the Effect of Allocentric Audiovisual Reference Frame

    Directory of Open Access Journals (Sweden)

    David Hartnagel

    2011-10-01

    Full Text Available Visual allocentric references frames (contextual cues affect visual space perception (Diedrichsen et al., 2004; Walter et al., 2006. On the other hand, experiments have shown a change of visual perception induced by binaural stimuli (Chandler, 1961; Carlile et al., 2001. In the present study we investigate the effect of visual and audiovisual allocentred reference frame on visual localization and straight ahead pointing. Participant faced a black part-spherical screen (92cm radius. The head was maintained aligned with the body. Participant wore headphone and a glove with motion capture markers. A red laser point was displayed straight ahead as fixation point. The visual target was a 100ms green laser point. After a short delay, the green laser reappeared and participant had to localize target with a trackball. Straight ahead blind pointing was required before and after series of 48 trials. Visual part of the bimodal allocentred reference frame was provided by a vertical red laser line (15° left or 15° right, auditory part was provided by 3D sound. Five conditions were tested, no-reference, visual reference (left/right, audiovisual reference (left/right. Results show that the significant effect of bimodal audiovisual reference is not different from the visual reference one.

  6. Overall properties of the Gaia DR1 reference frame

    Science.gov (United States)

    Liu, N.; Zhu, Z.; Liu, J.-C.; Ding, C.-Y.

    2017-03-01

    Aims: The first Gaia data release (Gaia DR1) provides 2191 ICRF2 sources with their positions in the auxiliary quasar solution and five astrometric parameters - positions, parallaxes, and proper motions - for stars in common between the Tycho-2 catalogue and Gaia in the joint Tycho-Gaia astrometric solution (TGAS). We aim to analyze the overall properties of Gaia DR1 reference frame. Methods: We compare quasar positions of the auxiliary quasar solution with ICRF2 sources using different samples and evaluate the influence on the Gaia DR1 reference frame owing to the Galactic aberration effect over the J2000.0-J2015.0 period. Then we estimate the global rotation between TGAS with Tycho-2 proper motion systems to investigate the property of the Gaia DR1 reference frame. Finally, the Galactic kinematics analysis using the K-M giant proper motions is performed to understand the property of Gaia DR1 reference frame. Results: The positional comparison between the auxiliary quasar solution and ICRF2 shows negligible orientation and validates the declination bias of -0.1mas in Gaia quasar positions with respect to ICRF2. Galactic aberration effect is thought to cause an offset 0.01mas of the Z axis direction of Gaia DR1 reference frame. The global rotation between TGAS and Tycho-2 proper motion systems, obtained by different samples, shows a much smaller value than the claimed value 0.24mas yr-1. For the Galactic kinematics analysis of the TGAS K-M giants, we find possible non-zero Galactic rotation components beyond the classical Oort constants: the rigid part ωYG = -0.38±0.15mas yr-1 and the differential part ω^primeYG = -0.29±0.19mas yr-1 around the YG axis of Galactic coordinates, which indicates possible residual rotation in Gaia DR1 reference frame or problems in the current Galactic kinematical model. Conclusions: The Gaia DR1 reference frame is well aligned to ICRF2, and the possible influence of the Galactic aberration effect should be taken into consideration

  7. 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.

  8. Gaia Data Release 1: The reference frame and the optical properties of ICRF sources

    CERN Document Server

    Mignard, F; Lindegren, L; Bastian, U; Bombrun, A; Hernandez, J; Hobbs, D; Lammers, U; Michalik, D; Ramos-Lerate, M; Biermann, M; Butkevich, A; Comoretto, G; Joliet, E; Holl, B; Hutton, A; Parsons, P; Steidelmueller, H; Andrei, A; Bourda, G; Charlot, P

    2016-01-01

    As part of the data processing for Gaia Data Release~1 (Gaia DR1) a special astrometric solution was computed, the so-called auxiliary quasar solution. This gives positions for selected extragalactic objects, including radio sources in the second realisation of the International Celestial Reference Frame (ICRF2) that have optical counterparts bright enough to be observed with Gaia. A subset of these positions was used to align the positional reference frame of Gaia DR1 with the ICRF2. We describe the properties of the Gaia auxiliary quasar solution for a subset of sources matched to ICRF2, and compare their optical and radio positions at the sub-mas level. Their formal standard errors are better than 0.76~milliarcsec (mas) for 50% of the sources and better than 3.35~mas for 90%. Optical magnitudes are obtained in Gaia's unfiltered photometric G band. The comparison with the radio positions of the defining sources shows no systematic differences larger than a few tenths of a mas. The fraction of questionable s...

  9. The nature and purposes of the Common Frame of Reference

    NARCIS (Netherlands)

    Beale, H.

    2008-01-01

    In this paper, I explain what I, as one of the 'academic researchers', understand to be the purposes of the Common Frame of Reference (CFR), and why I think it deserves support from academic and practising lawyers and businesspeople across Europe.

  10. Developing a Frame of Reference for understanding configuration systems

    DEFF Research Database (Denmark)

    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...

  11. 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.

  12. 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.

  13. 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

  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. VLBI terrestrial reference frame contributions to ITRF2008

    Science.gov (United States)

    Böckmann, Sarah; Artz, T.; Nothnagel, A.

    2010-03-01

    In late 2008, the Product Center for the International Terrestrial Reference Frame (ITRF) of the International Earth Rotation and Reference Systems Service (IERS) issued a call for contributions to the next realization of the International Terrestrial Reference System, ITRF2008. The official contribution of the International VLBI Service for Geodesy and Astrometry (IVS) to ITRF2008 consists of session-wise datum-free normal equations of altogether 4,539 daily Very Long Baseline Interferometry (VLBI) sessions from 1979.7 to 2009.0 including data of 115 different VLBI sites. It is the result of a combination of individual series of session-wise datum-free normal equations provided by seven analysis centers (ACs) of the IVS. All series are completely reprocessed following homogeneous analysis options according to the IERS Conventions 2003 and IVS Analysis Conventions. Altogether, nine IVS ACs analyzed the full history of VLBI observations with four different software packages. Unfortunately, the contributions of two ACs, Institute of Applied Astronomy (IAA) and Geoscience Australia (AUS), had to be excluded from the combination process. This was mostly done because the IAA series exhibits a clear scale offset while the solution computed from normal equations contained in the AUS SINEX files yielded unreliable results. Based on the experience gathered since the combination efforts for ITRF2005, some discrepancies between the individual series were discovered and overcome. Thus, the consistency of the individual VLBI solutions has improved considerably. The agreement in terms of WRMS of the Terrestrial Reference Frame (TRF) horizontal components is 1 mm, of the height component 2 mm. Comparisons between ITRF2005 and the combined TRF solution for ITRF2008 yielded systematic height differences of up to 5 mm with a zonal signature. These differences can be related to a pole tide correction referenced to a zero mean pole used by four of five IVS ACs in the ITRF2005

  16. 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

  17. Gaia Data Release 1. Reference frame and optical properties of ICRF sources

    Science.gov (United States)

    Mignard, F.; Klioner, S.; Lindegren, L.; Bastian, U.; Bombrun, A.; Hernández, J.; Hobbs, D.; Lammers, U.; Michalik, D.; Ramos-Lerate, M.; Biermann, M.; Butkevich, A.; Comoretto, G.; Joliet, E.; Holl, B.; Hutton, A.; Parsons, P.; Steidelmüller, H.; Andrei, A.; Bourda, G.; Charlot, P.

    2016-11-01

    Context. As part of the data processing for Gaia Data Release 1 (Gaia DR1) a special astrometric solution was computed, the so-called auxiliary quasar solution. This gives positions for selected extragalactic objects, including radio sources in the second realisation of the International Celestial Reference Frame (ICRF2) that have optical counterparts bright enough to be observed with Gaia. A subset of these positions was used to align the positional reference frame of Gaia DR1 with the ICRF2. Although the auxiliary quasar solution was important for internal validation and calibration purposes, the resulting positions are in general not published in Gaia DR1. Aims: We describe the properties of the Gaia auxiliary quasar solution for a subset of sources matched to ICRF2, and compare their optical and radio positions at the sub-mas level. Methods: Descriptive statistics are used to characterise the optical data for the ICRF sources and the optical-radio differences. The most discrepant cases are examined using online resources to find possible alternative explanations than a physical optical-radio offset of the quasars. Results: In the auxiliary quasar solution 2191 sources have good optical positions matched to ICRF2 sources with high probability. Their formal standard errors are better than 0.76 milliarcsec (mas) for 50% of the sources and better than 3.35 mas for 90%. Optical magnitudes are obtained in Gaia's unfiltered photometric G band. The Gaia results for these sources are given as a separate table in Gaia DR1. The comparison with the radio positions of the defining sources shows no systematic differences larger than a few tenths of a mas. The fraction of questionable solutions, not readily accounted for by the statistics, is less than 6%. Normalised differences have extended tails requiring case-by-case investigations for around 100 sources, but we have not seen any difference indisputably linked to an optical-radio offset in the sources. Conclusions: With

  18. 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

  19. Causality, relativity and quantum correlation experiments with moving reference frames

    Indian Academy of Sciences (India)

    H Zbinden; J Brendel; W Tittel; N Gisin

    2001-02-01

    Entanglement, one of the most important features of quantum mechanics, is at the core of the famous Einstein–Bohr philosophical debate [1] and is the principal resource for quantum information processing [2]. We report on new experimental investigations of the properties of entangled photon pairs with emphasis on the tension between quantum mechanics and relativity [3,4]. Entangled photons are sent via an optical fiber network to two villages near Geneva, separated by more than 10 km where they are analyzed by interferometers [5]. The photon pair source is set as precisely as possible in the center so that the two photons arrive at the detectors within a time interval of less than 5 ps (corresponding to a path length difference of less than 1 mm). This sets a lower bound on the ‘speed of quantum information’ to 107 times the speed of light. Next, one detector is set in motion [6] so that both detectors, each in its own inertial reference frame, are first to do the measurement! The data always reproduces the quantum correlations.

  20. 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

  1. 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.

  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. Photometric Observations of Selected, Optically Bright Quasars for Space Interferometry Mission and Other Future Celestial Reference Frames

    Science.gov (United States)

    2009-07-31

    SDSS r-magnitude Figure 8. Plot of (r−R), the difference of the SDSS r magnitude and observed R magnitude, against SDSS r magnitude -0.2 0 0.2 0.4...0.6 0.8 1 1.2 1.4 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 1.4 (g -r ) m ag ni tu de (V-R) magnitude Figure 9. Color–color plot of SDSS (g−r) against...with SDSS We also made a comparison of our results with a dedicated sample, the Sloan Digital Sky Survey ( SDSS DR5; Adelman- McCarthy et al. 2007

  4. Combination of Vlbi, GPS and Slr Observations At The Observation Level For The Realization of Terrestrial and Celestial Reference Frames

    Science.gov (United States)

    Andersen, P. H.

    Forsvarets forskningsinstitutt (FFI, the Norwegian Defence Research Establishment) has during the last 17 years developed a software system called GEOSAT, for the analysis of any type of high precision space geodetic observations. A unique feature of GEOSAT is the possibility of combining any combination of different space geode- tic data at the observation level with one consistent model and one consistent strategy. This is a much better strategy than the strategy in use today where different types of observations are processed separately using analysis software developed specifically for each technique. The results from each technique are finally combined a posteriori. In practice the models implemented in the software packages differ at the 1-cm level which is almost one order of magnitude larger than the internal precision of the most precise techniques. Another advantage of the new proposed combination method is that for example VLBI and GPS can use the same tropospheric model with common parameterization. The same is the case for the Earth orientation parameters, the geo- center coordinates and other geodetic or geophysical parameters where VLBI, GPS and SLR can have a common estimate for each of the parameters. The analysis with GEOSAT is automated for the combination of VLBI, SLR and GPS observations. The data are analyzed in batches of one day where the result from each daily arc is a SRIF array (Square Root Information Filter). A large number of SRIF arrays can be combined into a multi-year solution using the CSRIFS program (Com- bination Square Root Information Filter and Smoother). Four parameter levels are available and any parameter can, at each level, either be represented as a constant or a stochastic parameter (white noise, colored noise, or random walk). The batch length (i.e. the time interval between the addition of noise to the SRIF array) can be made time- and parameter dependent. GEOSAT and CSRIFS have been applied in the analysis of selected VLBI and SLR data (LAGEOS I &II) from the period January 1993 to July 2001. A selected number of arcs also include GPS data. Earth orientation parameters, geocenter motion, sta- tion coordinates and velocities were estimated simultaneously with the coordinates of the radio sources and satellite orbital parameters. Recent software improvements and 1 results of analyses will be presented at the meeting. 2

  5. 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...

  6. Eye movement suppression interferes with construction of object-centered spatial reference frames in working memory

    DEFF Research Database (Denmark)

    Wallentin, Mikkel; Kristensen, Line Burholt; Olsen, Jacob Hedeager

    2011-01-01

    of an object-centered, rather than egocentric, spatial reference frame. In this behavioral experiment we wanted to demonstrate a causal relationship between eye movement control and manipulation of spatial reference frames. Sixty two participants recalled either spatial ("Was X in front of Y?") or non...... were significantly slower for spatial relations with distraction while there was no effect on non-spatial relations. There was no effect on accuracy, i.e. WM maintenance. This is consistent with the hypothesis that in spatial representations the FEFs are involved in WM content manipulation......, such as establishing an object-centered spatial frame of reference....

  7. Moving Frames of Reference, Relativity and Invariance in Transfer Entropy and Information Dynamics

    Directory of Open Access Journals (Sweden)

    Joseph T. Lizier

    2013-01-01

    Full Text Available We present a new interpretation of a local framework for informationdynamics, including the transfer entropy, by defining a moving frame of reference for theobserver of dynamics in lattice systems. This formulation is inspired by the idea ofinvestigating “relativistic” effects on observing the dynamics of information - in particular,we investigate a Galilean transformation of the lattice system data. In applying thisinterpretation to elementary cellular automata, we demonstrate that using a moving frameof reference certainly alters the observed spatiotemporal measurements of informationdynamics, yet still returns meaningful results in this context. We find that, as expected,an observer will report coherent spatiotemporal structures that are moving in their frame asinformation transfer, and structures that are stationary in their frame as information storage.Crucially, the extent to which the shifted frame of reference alters the results dependson whether the shift of frame retains, adds or removes relevant information regarding thesource-destination interaction.

  8. 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.

  9. 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.

  10. Spin path integral and quantum mechanics in the rotating frame of reference%Spin path integral and quantum mechanics in the rotating frame of reference

    Institute of Scientific and Technical Information of China (English)

    CHEN Tong; WU Ning; YU Yue

    2011-01-01

    We have developed a path integral formalism of the quantum mechanics in the rotating frame of reference, and proposed a path integral description of spin degrees of freedom, which is connected to the Schwinger bosons realization of the angular momenta. We

  11. Motion, frames of reference, dead horses, and metaphysics (comment on Stoffregen & Bardy, 2001)

    NARCIS (Netherlands)

    Wertheim, A.H.

    2001-01-01

    Various annoyingly incorrect statements of Stoffregen & Bardy are corrected, for example, that perception researchers commonly use the term "absolute motion" to denote motion without any frame of reference, confuse earth-relative and gravity-relative motion, err with respect to the frame of referenc

  12. Reference Frames and Coordinate Transformations for Advanced Post-Newtonian Theory of the Lunar Motion

    CERN Document Server

    Xie, Yi

    2009-01-01

    We construct a set of reference frames for description of the orbital and rotational motion of the Moon. We use a scalar-tensor theory of gravity depending on two parameters of the parametrized post-Newtonian (PPN) formalism and utilize the concepts of 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. The primary reference frame has the origin at the solar-system barycenter (SSB) and spatial axes are going to infinity. The SSB frame is not rotating with respect to distant quasars. The secondary reference frame has the origin at the Earth-Moon barycenter (EMB). The EMB frame is local with its spatial axes spreading out to the orbits of Venus and Mars and not rotating dynamically in the sense that both the Coriolis and centripetal forces acting on a free-falling test particle, moving with respect to the EMB frame, are excluded. Two other local frames, the geocentric (GRF) an...

  13. Academe, Technology, Society, and the Market: Four Frames of Reference for Copyright and Fair Use.

    Science.gov (United States)

    Metcalfe, Amy; Diaz, Veronica; Wagoner, Richard

    2003-01-01

    Suggests that varied and often understated uses of copyrighted materials exist in academic settings. Introduces four "frames" of reference: Academic, Technological, Social, and Market. Presents court cases relevant to each frame. Explores two scenarios involving use of copyrighted materials. As technology increases both access and control, the…

  14. Locally Inertial Reference Frames in Lorentzian and Riemann-Cartan Spacetimes

    CERN Document Server

    Giglio, J F T

    2011-01-01

    In this paper we scrutinize the concept of locally inertial reference frames (LIRF) in Lorentzian and Riemann-Cartan spacetime structures. We present rigorous mathematical definitions for those objects, something that needs preliminary a clear mathematical distinction between the concepts of observers, reference frames, naturally adapted coordinate functions to a given reference frame and which properties may characterize an inertial reference frame (if any) in the Lorentzian and Riemann-Cartan structures. We hope to have clarified some eventual obscure issues associated to the concept of LIRF appearing in the literature, in particular the relationship between LIRFs in Lorentzian and Riemann-Cartan spacetimes and Einstein's most happy though, i.e., the equivalence principle.

  15. The task of the relativistic oscillator in a non-inertial frame of reference

    Science.gov (United States)

    Perepelkin, E. E.; Sadovnikov, B. I.; Inozemtseva, N. G.

    2016-09-01

    The relativistic theory is one of the most difficult parts of theoretical physics to understand by high school students and scientists alike. In this paper, the important aspects from this theory are considered. The case of the non-inertial reference frame in which the space-time interval was presented for the Lorentz-like transformations, and the condition by which the transition to the inertial reference frame takes place, is shown.

  16. The role of perspective taking in how children connect reference frames when explaining astronomical phenomena

    Science.gov (United States)

    Plummer, Julia D.; Bower, Corinne A.; Liben, Lynn S.

    2016-02-01

    This study investigates the role of perspective-taking skills in how children explain spatially complex astronomical phenomena. Explaining many astronomical phenomena, especially those studied in elementary and middle school, requires shifting between an Earth-based description of the phenomena and a space-based reference frame. We studied 7- to 9-year-old children (N = 15) to (a) develop a method for capturing how children make connections between reference frames and to (b) explore connections between perspective-taking skill and the nature of children's explanations. Children's explanations for the apparent motion of the Sun and stars and for seasonal changes in constellations were coded for accuracy of explanation, connection between frames of reference, and use of gesture. Children with higher spatial perspective-taking skills made more explicit connections between reference frames and used certain gesture-types more frequently, although this pattern was evident for only some phenomena. Findings suggest that children - particularly those with lower perspective-taking skills - may need additional support in learning to explicitly connect reference frames in astronomy. Understanding spatial thinking among children who successfully made explicit connections between reference frames in their explanations could be a starting point for future instruction in this domain.

  17. Frames of reference that address the impact of physical environments on occupational performance.

    Science.gov (United States)

    Whedon, Caren A.

    2000-01-01

    A frame of reference is the mechanism for linking theory to practice. It may be the most practical and important tool a professional uses. As the practice of occupational therapy has evolved, so has the basis of information, or theories, on which it is grounded. From the theories, models have been developed that typically view occupational performance as a transaction between the person, occupation and environment. Occupational therapy practitioners use many frames of reference. Not all of them address all areas of occupational performance identified within this overarching model. Often the area of the environment does not receive attention. To do their jobs thoroughly, occupational therapy practitioners need frames of reference for thinking about the environment. The purpose of this paper is to identify and explore frames of reference that may be useful to occupational therapy practitioners when they are taking into consideration the physical environment. Included are the following frames of reference: ergonomics, industrial hygiene, environmental psychology, accessibility and feng shui. A case study is presented to illustrate the unique perspective of each frame of reference.

  18. Testing Absolute Plate Reference Frames and the Implications for the Generation of Geodynamic Mantle Heterogeneity Structure

    Science.gov (United States)

    Shephard, G. E.; Bunge, H.; Schuberth, B. S.; Müller, D.; Talsma, A.; Moder, C.

    2010-12-01

    Several absolute reference frames for Cretaceous-Tertiary plate tectonic reconstructions have been proposed over the last decade. They include reference frames based on hotspot tracks displaying age progression, and assuming either fixed or moving hotspots, as well as palaeomagnetically-based reference frames, a subduction reference frame and hybrid reference frames. All these alternative reference frames imply a particular history of the location of subduction zones through time, the associated subduction history, and the evolution of mantle heterogeneity via the mixing of subducted slab material with the mantle. Therefore it is possible to evaluate the observed distribution of subducted slab material in the mantle versus that predicted by a forward geodynamic model in which the plate kinematic history given by a particular absolute plate is coupled with a mantle convection model. We present a comparison of five alternative absolute plate motion models in terms of their consequences for global deep mantle structure by utilizing the 3-D spherical finite element mantle convection code TERRA, coupled with the global plate tectonic reconstruction software GPlates. We impose global palaeo-plate boundaries and plate velocities back to 140 Ma as surface boundary conditions for each absolute rotation model and forward model the associated subduction history. The correlation of seismic tomography with the predicted present-day mantle structure from each of plate models is then assessed using well-imaged slabs. We will present and discuss a comparison of geodynamically predicted mantle heterogeneity and seismic tomography to infer the robustness of each absolute reference frame through time, thus providing additional constraints for the integration of plate tectonics and mantle dynamics.

  19. Binocular perception of slant about oblique axes relative to a visual frame of reference

    NARCIS (Netherlands)

    Ee, R. van; Erkelens, Casper J.

    2001-01-01

    From the literature it is known that the processing of disparity for slant is different in the presence and in the absence of a visual frame of reference. We elaborate the experimental finding that vertical disparity is not processed for slant perception in the presence of a visual reference. This t

  20. About Lorentz-M{\\o}ller-Nelson transformation to rigid noninertial frame of reference

    CERN Document Server

    Voytik, Vitaliy V

    2012-01-01

    With a special Lorentz-M{\\o}ller-Nelson (LMN) transformation found transformation of velocity from the laboratory system S to an arbitrary rigid progressively moving reference frame s. Set the physical meaning of the parameter $\\mathbf{v}(t)$ in the appropriate LMN transformation. For small distances, and their proper smooth motion without jerks suggested the reverse special LMN transformation. The main consequences of this transformation is considered, namely, a) the desync in moving frame of reference s of proper clocks of the pre-synchronized in the laboratory frame S and b) the Lorentz contraction of proper rulers frame s in the frame S. The applicability of the reverse LMN transformation for real frames with maximum rigidity is established. Equations for the rotation matrix is obtained. It is shown that the intrinsic rotation of the axes s, considered with respect to S is not rigid. Found the direct and inverse transformation of affine velocity S in the comoving but not rotating frame of s. It is shown t...

  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. Thermodynamic Properties of Spherically-Symmetric, Uniformly-Accelerated Reference Frames

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jian-Bao; HUANG Chao-Guang; LIU Zeng-Rong; SUN Jia-Rui; LI Ying

    2008-01-01

    We aim to study the thermodynamic properties of the spherically symmetric reference frames with uniform acceleration, including the spherically symmetric generalization of Rindler reference frame and the new kind of uniformly accelerated reference frame. We find that, unlike the general studies about the horizon thermodynamics, one cannot obtain the laws of thermodynamics for their horizons in the usual approaches, despite that one can formally define an area entropy (Bekenstein-Hawking entropy). In fact, the common horizon for a set of uniformly accelerated observers does not always exist, even though the Hawking-Unruh temperature is still well-defined. This result indicates that the Hawking-Unruh temperature is only a kinematic effect, and to gain the laws of thermodynamics for the horizon, one needs the help of dynamics. Our result is in accordance with those from the various studies about the acoustic black holes.

  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

    . 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...... are presented to verify the effectiveness of the proposed modeling and control method....

  4. Quantum mechanics in noninertial reference frames: Relativistic accelerations and fictitious forces

    Energy Technology Data Exchange (ETDEWEB)

    Klink, W.H., E-mail: william-klink@uiowa.edu [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States); Wickramasekara, S., E-mail: wickrama@grinnell.edu [Department of Physics, Grinnell College, Grinnell, IA 50112 (United States)

    2016-06-15

    One-particle systems in relativistically accelerating reference frames can be associated with a class of unitary representations of the group of arbitrary coordinate transformations, an extension of the Wigner–Bargmann definition of particles as the physical realization of unitary irreducible representations of the Poincaré group. Representations of the group of arbitrary coordinate transformations become necessary to define unitary operators implementing relativistic acceleration transformations in quantum theory because, unlike in the Galilean case, the relativistic acceleration transformations do not themselves form a group. The momentum operators that follow from these representations show how the fictitious forces in noninertial reference frames are generated in quantum theory.

  5. The task of the relativistic oscillator in a non-inertial frame of reference

    CERN Document Server

    Perepelkin, E E; Inozemtseva, N G

    2016-01-01

    In this paper the analogues of the Lorentz transformations for non-inertial reference frames have been obtained. A common case when the movement speed of one coordinate frame in relation to another one can have time derivatives of higher orders. The obtained transformations conserve invariance of the space-time interval, and in the particular case of inertial frames become the well-known Lorentz transformations. It is shown that the transition from classical mechanics to the theory of relativity is analogous to the consideration of the vibrating system described by the equation of the sine-Gordon type. In this case, if the amplitude of the elliptic functions is $k\\to 0$ the fluctuations can be considered small, and that leads to classical mechanics. With $k\\to 1$ time depends on the vibration amplitude, which leads to the theory of relativity. In the case of inertial frames the amplitude is $k=\\beta ={v}/{c}\\;$.

  6. Maintenance of the Geodetic Reference Frame in the Global Positioning System

    Science.gov (United States)

    Oria, A.; Brodsky, B. L.; Labrecque, J.; Miller, J. J.; Moreau, M.; Pearlman, M.; Nelson, R.

    2007-12-01

    In the Global Positioning System (GPS) measurements of the satellite coordinates and the underlying World Geodetic System 1984 (WGS 84) reference frame are derived from observables such as pseudorandom noise (PRN) signals, and carrier phase, which are referenced to on-board atomic clocks. Systematic errors exist in both the estimated satellite coordinates and the reference frame. The reference frame utilizes external inputs in the form of International Terrestrial Reference Frame (ITRF) coordinates and constrains the results to be compatible with the ITRF coordinates for a set of global reference stations. The ITRF is, in turn, obtained from the combined analysis of GPS, Satellite Laser Ranging (SLR), Very Long Baseline Interferometry (VLBI), and Doppler Orbitography and Radio-positioning Integrated by Satellite (DORIS) data. The current realization of the reference frame could be described as circular in that an independent method of external verification is currently not available. To ensure the continued successful operation of the GPS it is necessary to have the capability of analyzing systematic errors by an independent means from current radiometric observables and data from foreign sources. In practice, accuracy of the standards used for measurement should be better than the expected, required operational measurement accuracy by a factor of ten to ensure that the desired requirement is met. Currently, the accuracy of both the ITRF and the WGS 84 is estimated to be on the order of 1 to 2 parts per billion, leading to expected drifts of 0.6 to 1.2 cm per year. The experience of the last three decades has indicated an approximate improvement by a factor of ten per decade. Therefore, while current accuracy of the ITRF and WGS 84 reference frames marginally meets civilian and military requirements, it is very likely that, within the lifetime of GPS III, the accuracy of the reference frames will be unable to meet the anticipated requirements. This report examines

  7. Sometimes losing your self in space: Children's and adults' spontaneous use of multiple spatial reference frames

    NARCIS (Netherlands)

    Surtees, Andrew D.R.; Noordzij, Matthijs L.; Apperly, Ian A.

    2012-01-01

    Two experiments tested 6- to 11-year-old children's and college students' use of different frames of reference when making judgments about descriptions of social and nonsocial scenes. In Experiment 1, when social and nonsocial scenes were mixed, both children and students (N = 144) showed spontaneou

  8. The Role of Perspective Taking in How Children Connect Reference Frames When Explaining Astronomical Phenomena

    Science.gov (United States)

    Plummer, Julia D.; Bower, Corinne A.; Liben, Lynn S.

    2016-01-01

    This study investigates the role of perspective-taking skills in how children explain spatially complex astronomical phenomena. Explaining many astronomical phenomena, especially those studied in elementary and middle school, requires shifting between an Earth-based description of the phenomena and a space-based reference frame. We studied 7- to…

  9. 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…

  10. Allocentric and egocentric reference frames in the processing of three-dimensional haptic space

    NARCIS (Netherlands)

    Volcic, R.; Kappers, A.M.L.

    2008-01-01

    The main goal of our study is to gain insight into the reference frames involved in three-dimensional haptic spatial processing. Previous research has shown that two-dimensional haptic spatial processing is prone to large systematic deviations. A weighted average model that identifies the origin of

  11. Somali refugees' experiences with their general practitioners: frames of reference and critical episodes.

    NARCIS (Netherlands)

    Feldmann, C.T.; Bensing, J.M.; Ruijter, A. de; Boeije, H.R.

    2006-01-01

    The article presents the results of a qualitative study based on in-depth interviews with Somali refugees living in The Netherlands, on their experiences with general practitioners (GPs). The central question is: what are the frames of reference participants use to interpret their experiences? The c

  12. Somali refugees’ experiences with their general practitioners: frames of reference and critical episodes

    NARCIS (Netherlands)

    Titia Feldmann, C.; Bensing, J.; Ruijter, Arie de; Boeije, H.R.

    2006-01-01

    The article presents the results of a qualitative study based on in-depth interviews with Somali refugees living in The Netherlands, on their experiences with general practitioners (GPs). The central question is: what are the frames of reference participants use to interpret their experiences? The c

  13. 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

  14. Antecedents of Academic Emotions: Testing the Internal/External Frame of Reference Model for Academic Enjoyment

    Science.gov (United States)

    Goetz, Thomas; Frenzel, Anne C.; Hall, Nathan C.; Pekrun, Reinhard

    2008-01-01

    The present study focused on students' academic enjoyment as predicted by achievement in multiple academic domains. Assumptions were based on Marsh's internal/external (I/E) frame of reference model and Pekrun's control-value theory of achievement emotions, and were tested in a sample of 1380 German students from grades 5 to 10. Students' academic…

  15. "When was that date?" Building and assessing a frame of reference in the Netherlands

    NARCIS (Netherlands)

    van Drie, J.; Logtenberg, A.; van der Meijden, B.; van Riessen, M.

    2009-01-01

    Concerns about our ability to equip young people with a frame of reference that they can actually use to orient themselves in time are widespread. The challenges were extensively debated within the last issue of Teaching History, with teachers, researchers and historians not only exploring the merit

  16. Myths, Misconceptions, and Misunderstandings: A Different Spin on Coriolis--Applying Frame of Reference

    Science.gov (United States)

    DiSpezio, Michael A.

    2011-01-01

    This article addresses misconceptions surrounding the Coriolis force and describes how it should be presented as a function within inertial and noninertial frames of reference. Not only does this demonstrate the nature of science as it strives to best interpret the natural world (and presents alternative explanations), but it offers a rich…

  17. Aligning Body and World: Stable Reference Frames Improve Young Children's Search for Hidden Objects

    Science.gov (United States)

    Perry, Lynn K.; Samuelson, Larissa K.; Spencer, John P.

    2009-01-01

    This study investigated how young children's increasingly flexible use of spatial reference frames enables accurate search for hidden objects by using a task that 3-year-olds have been shown to perform with great accuracy and 2-year-olds have been shown to perform inaccurately. Children watched as an object was rolled down a ramp, behind a panel…

  18. 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…

  19. Accuracy of the International Terrestrial Reference Frame origin and Earth expansion

    NARCIS (Netherlands)

    Wu, X.; Collilieux, X.; Altamimi, Z.; Vermeersen, L.L.A.; Gross, R.S.; Fukumori, I.

    2011-01-01

    The International Terrestrial Reference Frame (ITRF) is a fundamental datum for high‐precision orbit tracking, navigation, and global change monitoring. Accurately realizing and maintaining ITRF origin at the mean Earth system center of mass (CM) is critical to surface and spacecraft based geodetic

  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. 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

  2. Quantum mechanics in non-inertial reference frames: Time-dependent rotations and loop prolongations

    Energy Technology Data Exchange (ETDEWEB)

    Klink, W.H., E-mail: william-klink@uiowa.edu [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States); Wickramasekara, S., E-mail: wickrama@grinnell.edu [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States); Department of Physics, Grinnell College, Grinnell, IA 50112 (United States)

    2013-09-15

    This is the fourth in a series of papers on developing 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 to include transformations amongst non-inertial reference frames. These representations show that in quantum mechanics, just as the case in classical mechanics, the transformations to accelerating reference frames give rise to fictitious forces. In previous work, we have shown that there exist representations of the Galilean line group that uphold the non-relativistic equivalence principle as well as representations that violate the equivalence principle. In these previous studies, the focus was on linear accelerations. In this paper, we undertake an extension of the formulation to include rotational accelerations. We show that the incorporation of rotational accelerations requires a class of loop prolongations of the Galilean line group and their unitary cocycle representations. We recover the centrifugal and Coriolis force effects from these loop representations. Loops are more general than groups in that their multiplication law need not be associative. Hence, our broad theoretical claim is that a Galilean quantum theory that holds in arbitrary non-inertial reference frames requires going beyond groups and group representations, the well-established framework for implementing symmetry transformations in quantum mechanics. -- Highlights: •A formulation of Galilean quantum mechanics in non-inertial reference frames is presented. •The Galilei group is generalized to infinite dimensional Galilean line group. •Loop prolongations of Galilean line group contain central extensions of Galilei group. •Unitary representations of the loops are constructed. •These representations lead to terms in the Hamiltonian corresponding to fictitious forces, including centrifugal and Coriolis

  3. Extrinsic reference frames modify the neural substrates of object-location representations.

    Science.gov (United States)

    Chan, Edgar; Baumann, Oliver; Bellgrove, Mark A; Mattingley, Jason B

    2013-04-01

    The ability to form spatial representations of object locations is an important component of successful spatial navigation. Evidence from behavioral studies suggests that environmental features that have a salient coordinate axis (e.g., a rectangular building or a geometrical room) may provide a reference frame for the encoding of object-location information. Here we used functional magnetic resonance imaging (fMRI) to determine the brain networks engaged when object-location representations are stored with respect to an extrinsic reference frame. Participants learned the layout of an object array in an active, virtual-navigation paradigm. A square mat positioned on the floor of the virtual arena acted as the extrinsic reference frame. Knowledge of the spatial arrangement of the object array was probed while participants underwent fMRI, using a spatial judgment task that required them to imagine orientations of the learned array that were either aligned or misaligned with the geometry of the mat. Consistent with previous findings, participants responded faster and were more accurate when the imagined orientation was aligned, as opposed to misaligned, with the extrinsic reference frame. Analysis of the fMRI data revealed important differences in brain activity between the two conditions. Significantly greater activity was observed in the aligned condition compared with the misaligned condition across a bilateral network of brain areas that included the inferior occipital gyri, inferior and middle temporal gyri, and fusiform gyri. By contrast, activity in the misaligned condition was significantly greater than in the aligned condition in bilateral dorsolateral prefrontal and anterior cingulate cortex, and in the right anterior prefrontal and anterior insular cortex. These results suggest that retrieval of spatial locations that are aligned with an extrinsic reference frame involve direct access to detailed and accurate representations within the ventral visual

  4. 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 fictitious current signal. Frequency-independent operation, accurate reference current extraction and relatively fast transient response are other key features of the presented strategy. The effectiveness of the proposed method is investigated by means of detailed mathematical analysis. The results confirm...

  5. 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.

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

    DEFF Research Database (Denmark)

    Krenk, Steen; Nielsen, Martin Bjerre

    2011-01-01

    displacements and the global velocities are represented by the same shape functions. This leads to a simple generalization of the corresponding equations of motion in a stationary frame in which all inertial effects are represented via the classic global mass matrix. The formulation introduces two gyroscopic......A time integration algorithm is developed for the equations of motion of a flexible body in a rotating frame of reference. The equations are formulated in a hybrid state‐space, formed by the local displacement components and the global velocity components. In the spatial discretization the local...... 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...

  7. 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

  8. Proof-of-principle experiment of reference-frame-independent quantum key distribution with phase coding

    Science.gov (United States)

    Liang, Wen-Ye; Wang, Shuang; Li, Hong-Wei; Yin, Zhen-Qiang; Chen, Wei; Yao, Yao; Huang, Jing-Zheng; Guo, Guang-Can; Han, Zheng-Fu

    2014-01-01

    We have demonstrated a proof-of-principle experiment of reference-frame-independent phase coding quantum key distribution (RFI-QKD) over an 80-km optical fiber. After considering the finite-key bound, we still achieve a distance of 50 km. In this scenario, the phases of the basis states are related by a slowly time-varying transformation. Furthermore, we developed and realized a new decoy state method for RFI-QKD systems with weak coherent sources to counteract the photon-number-splitting attack. With the help of a reference-frame-independent protocol and a Michelson interferometer with Faraday rotator mirrors, our system is rendered immune to the slow phase changes of the interferometer and the polarization disturbances of the channel, making the procedure very robust.

  9. On a Special Transformation to a Non-Inertial, Radially Rigid Reference Frame

    CERN Document Server

    Voytik, Vitaliy

    2013-01-01

    We discuss the conditions under which a body, moving non-inertially in Minkowski space, can preserve its size. Under these conditions, using a series expansion of the generalized Lorentz transformation, we ?nd a coor- dinate transformation connecting the laboratory inertial reference frame S and the rigid non-inertial reference frame s which moves without its own rotation with respect to S. Direct consequences of this transformation are: (a) desynchronization, in system s, of the coordinate clocks of s which were previously synchronized in S, and (b) a kinematic contraction of a ruler of system s observed in S. We also consider the dependence of the transfor- mation vector parameter on the proper coordinates of s.

  10. A computational model for reference-frame synthesis with applications to motion perception.

    Science.gov (United States)

    Clarke, Aaron M; Öğmen, Haluk; Herzog, Michael H

    2016-09-01

    As discovered by the Gestaltists, in particular by Duncker, we often perceive motion to be within a non-retinotopic reference frame. For example, the motion of a reflector on a bicycle appears to be circular, whereas, it traces out a cycloidal path with respect to external world coordinates. The reflector motion appears to be circular because the human brain subtracts the horizontal motion of the bicycle from the reflector motion. The bicycle serves as a reference frame for the reflector motion. Here, we present a general mathematical framework, based on vector fields, to explain non-retinotopic motion processing. Using four types of non-retinotopic motion paradigms, we show how the theory works in detail. For example, we show how non-retinotopic motion in the Ternus-Pikler display can be computed.

  11. Bounds for reference-frame independent protocols in quantum cryptography using generalized uncertainty relations

    CERN Document Server

    Le, Thinh Phuc; Scarani, Valerio

    2011-01-01

    We define a family of reference-frame-independent quantum cryptography protocols for arbitrary dimensional signals. The generalized entropic uncertainty relations [M. Tomamichel and R. Renner, Phys. Rev. Lett. 106, 110506 (2011)] are used for the first time to derive security bounds for protocols which use more than two measurements and combine the statistics in a non-linear parameter. This shows the power and versatility of this technique compared to the heavier, though usually tighter, conventional techniques.

  12. Generalization of Dexterous Manipulation Is Sensitive to the Frame of Reference in Which It Is Learned.

    Science.gov (United States)

    Marneweck, Michelle; Knelange, Elisabeth; Lee-Miller, Trevor; Santello, Marco; Gordon, Andrew M

    2015-01-01

    Studies have shown that internal representations of manipulations of objects with asymmetric mass distributions that are generated within a specific orientation are not generalizable to novel orientations, i.e., subjects fail to prevent object roll on their first grasp-lift attempt of the object following 180° object rotation. This suggests that representations of these manipulations are specific to the reference frame in which they are formed. However, it is unknown whether that reference frame is specific to the hand, the body, or both, because rotating the object 180° modifies the relation between object and body as well as object and hand. An alternative, untested explanation for the above failure to generalize learned manipulations is that any rotation will disrupt grasp performance, regardless if the reference frame in which the manipulation was learned is maintained or modified. We examined the effect of rotations that (1) maintain and (2) modify relations between object and body, and object and hand, on the generalizability of learned two-digit manipulation of an object with an asymmetric mass distribution. Following rotations that maintained the relation between object and body and object and hand (e.g., rotating the object and subject 180°), subjects continued to use appropriate digit placement and load force distributions, thus generating sufficient compensatory moments to minimize object roll. In contrast, following rotations that modified the relation between (1) object and hand (e.g. rotating the hand around to the opposite object side), (2) object and body (e.g. rotating subject and hand 180°), or (3) both (e.g. rotating the subject 180°), subjects used the same, yet inappropriate digit placement and load force distribution, as those used prior to the rotation. Consequently, the compensatory moments were insufficient to prevent large object rolls. These findings suggest that representations of learned manipulation of objects with asymmetric mass

  13. Generalization of Dexterous Manipulation Is Sensitive to the Frame of Reference in Which It Is Learned.

    Directory of Open Access Journals (Sweden)

    Michelle Marneweck

    Full Text Available Studies have shown that internal representations of manipulations of objects with asymmetric mass distributions that are generated within a specific orientation are not generalizable to novel orientations, i.e., subjects fail to prevent object roll on their first grasp-lift attempt of the object following 180° object rotation. This suggests that representations of these manipulations are specific to the reference frame in which they are formed. However, it is unknown whether that reference frame is specific to the hand, the body, or both, because rotating the object 180° modifies the relation between object and body as well as object and hand. An alternative, untested explanation for the above failure to generalize learned manipulations is that any rotation will disrupt grasp performance, regardless if the reference frame in which the manipulation was learned is maintained or modified. We examined the effect of rotations that (1 maintain and (2 modify relations between object and body, and object and hand, on the generalizability of learned two-digit manipulation of an object with an asymmetric mass distribution. Following rotations that maintained the relation between object and body and object and hand (e.g., rotating the object and subject 180°, subjects continued to use appropriate digit placement and load force distributions, thus generating sufficient compensatory moments to minimize object roll. In contrast, following rotations that modified the relation between (1 object and hand (e.g. rotating the hand around to the opposite object side, (2 object and body (e.g. rotating subject and hand 180°, or (3 both (e.g. rotating the subject 180°, subjects used the same, yet inappropriate digit placement and load force distribution, as those used prior to the rotation. Consequently, the compensatory moments were insufficient to prevent large object rolls. These findings suggest that representations of learned manipulation of objects with

  14. 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…

  15. 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 effectively...

  16. Human posterior parietal cortex flexibly determines reference frames for reaching based on sensory context.

    Science.gov (United States)

    Bernier, Pierre-Michel; Grafton, Scott T

    2010-11-18

    Current models of sensorimotor transformations emphasize the dominant role of gaze-centered representations for reach planning in the posterior parietal cortex (PPC). Here we exploit fMRI repetition suppression to test whether the sensory modality of a target determines the reference frame used to define the motor goal in the PPC and premotor cortex. We show that when targets are defined visually, the anterior precuneus selectively encodes the motor goal in gaze-centered coordinates, whereas the parieto-occipital junction, Brodman Area 5 (BA 5), and PMd use a mixed gaze- and body-centered representation. In contrast, when targets are defined by unseen proprioceptive cues, activity in these areas switches to represent the motor goal predominantly in body-centered coordinates. These results support computational models arguing for flexibility in reference frames for action according to sensory context. Critically, they provide neuroanatomical evidence that flexibility is achieved by exploiting a multiplicity of reference frames that can be expressed within individual areas.

  17. Extended intrinsic mean spin tensor for turbulence modelling in non-inertial frame of reference

    Institute of Scientific and Technical Information of China (English)

    HUANG Yu-ning; MA Hui-yang

    2008-01-01

    We investigate the role of extended intrinsic mean spin tensor introduced in this work for turbulence modelling in a non-inertial frame of reference.It is described by the Euclidean group of transformations and,in particular,its significance and importance in the approach of the algebraic Reynolds stress modelling,such as in a nonlinear K-εmodel.To this end and for illustration of the effect of extended intrinsic spin tensor on turbulence modelling,we examine several recently developed nonlinear K-ε models and compare their performance in predicting the homogeneous turbulent shear flow in a rotating frame of reference with LES data.Our results and analysis indicate that,only if the deficiencies of these models and the like be well understood and properly corrected,may in the near future,more sophisticated nonlinear K-ε models be 0eveloped to better predict complex turbulent flows in a non-inertial frame of reference.

  18. 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.

  19. Effects of adopting new precession, nutation and equinox corrections on the terrestrial reference frame

    Science.gov (United States)

    Zhu, Sheng-Yuan; Mueller, Ivan I.

    1983-03-01

    First, the paper is devoted to the effects of adopting new definitive precession and equinox corrections on the terrestrial reference frame: The effect on polar motion is a diurnal periodic term with an amplitude increasing linearly in time; on UT1 it is a linear term. Second, general principles are given the use of which can determine the effects of small rotations (such as precession, nutation or equinox corrections) of the frame of a Conventional Inertial Reference System (CIS) on the frame of the Conventional Terrestrial Reference System (CTS). Next, seven CTS options are presented, one of which is necessary to accommodate such rotations (corrections). The last of these options requiring no changes in the origin of terrestrial longitudes and in UT1 is advocated; this option would be maintained by eventually referencing the Greenwich Mean Sidereal Time to a fixed point on the equator, instead of to the mean equinox of date, the current practice. Accommodating possible future changes in the astronomical nutation is discussed in the last section. The Appendix deals with the effects of differences which may exist between the various CTS's and CIS's (inherent in the various observational techniques) on earth rotation parameters (ERP) and how these differences can be determined. It is shown that the CTS differences can be determined from observations made at the same site, while the CIS differences by comparing the ERP's determined by the different techniques during the same time period.

  20. Project Vesta: A Laboratory Exercise on the Measurement of Celestial Coordinates

    Science.gov (United States)

    Laird, David E.

    1974-01-01

    Described is an activity that was developed to measure celestial coordinates. Pictures were taken of the asteroid Vesta, coordinates for reference stars determined, and then celestial coordinates of Vesta were determined with assistance of a computer. (RH)

  1. Quantum reference frames associated with noncompact groups: The case of translations and boosts and the role of mass

    Science.gov (United States)

    Smith, Alexander R. H.; Piani, Marco; Mann, Robert B.

    2016-07-01

    Quantum communication without a shared reference frame or the construction of a relational quantum theory requires the notion of a quantum reference frame. We analyze aspects of quantum reference frames associated with noncompact groups, specifically, the group of spatial translations and Galilean boosts. We begin by demonstrating how the usually employed group average, used to dispense of the notion of an external reference frame, leads to unphysical states when applied to reference frames associated with noncompact groups. However, we show that this average does lead naturally to a reduced state on the relative degrees of freedom of a system, which was previously considered by Angelo et al. [J. Phys. A: Math. Theor. 44, 145304 (2011), 10.1088/1751-8113/44/14/145304]. We then study in detail the informational properties of this reduced state for systems of two and three particles in Gaussian states.

  2. Relativistic Celestial Mechanics of the Solar System

    Science.gov (United States)

    Kopeikin, Sergei; Efroimsky, Michael; Kaplan, George

    2011-09-01

    The general theory of relativity was developed by Einstein a century ago. Since then, it has become the standard theory of gravity, especially important to the fields of fundamental astronomy, astrophysics, cosmology, and experimental gravitational physics. Today, the application of general relativity is also essential for many practical purposes involving astrometry, navigation, geodesy, and time synchronization. Numerous experiments have successfully tested general relativity to a remarkable level of precision. Exploring relativistic gravity in the solar system now involves a variety of high-accuracy techniques, for example, very long baseline radio interferometry, pulsar timing, spacecraft Doppler tracking, planetary radio ranging, lunar laser ranging, the global positioning system (GPS), torsion balances and atomic clocks. Over the last few decades, various groups within the International Astronomical Union have been active in exploring the application of the general theory of relativity to the modeling and interpretation of high-accuracy astronomical observations in the solar system and beyond. A Working Group on Relativity in Celestial Mechanics and Astrometry was formed in 1994 to define and implement a relativistic theory of reference frames and time scales. This task was successfully completed with the adoption of a series of resolutions on astronomical reference systems, time scales, and Earth rotation models by the 24th General Assembly of the IAU, held in Manchester, UK, in 2000. However, these resolutions only form a framework for the practical application of relativity theory, and there have been continuing questions on the details of the proper application of relativity theory to many common astronomical problems. To ensure that these questions are properly addressed, the 26th General Assembly of the IAU, held in Prague in August 2006, established the IAU Commission 52, "Relativity in Fundamental Astronomy". The general scientific goals of the new

  3. Formal structures, the concepts of covariance, invariance, equivalent reference frames, and the principle Relativity

    Science.gov (United States)

    Rodrigues, W. A.; Scanavini, M. E. F.; de Alcantara, L. P.

    1990-02-01

    In this paper a given spacetime theory T is characterized as the theory of a certain species of structure in the sense of Bourbaki [1]. It is then possible to clarify in a rigorous way the concepts of passive and active covariance of T under the action of the manifold mapping group G M . For each T, we define also an invariance group G I T and, in general, G I T ≠ G M . This group is defined once we realize that, for each τ ∈ ModT, each explicit geometrical object defining the structure can be classified as absolute or dynamical [2]. All spacetime theories possess also implicit geometrical objects that do not appear explicitly in the structure. These implicit objects are not absolute nor dynamical. Among them there are the reference frame fields, i.e., “timelike” vector fields X ∈ TU,U subseteq M M, where M is a manifold which is part of ST, a substructure for each τ ∈ ModT, called spacetime. We give a physically motivated definition of equivalent reference frames and introduce the concept of the equivalence group of a class of reference frames of kind X according to T, G X T. We define that T admits a weak principle of relativity (WPR) only if G X T ≠ identity for some X. If G X T = G I T for some X, we say that T admits a strong principle of relativity (PR). The results of this paper generalize and clarify several results obtained by Anderson [2], Scheibe [3], Hiskes [4], Recami and Rodrigues [5], Friedman [6], Fock [7], and Scanavini [8]. Among the novelties here, there is the realization that the definitions of G I T and G X T can be given only when certain boundary conditions for the equations of motion of T can be physically realizable in the domain U U subseteq M M, where a given reference frame is defined. The existence of physically realizable boundary conditions for each τ ∈ ModT (in ∂ U), in contrast with the mathematically possible boundary condition, is then seen to be essential for the validity of a principle of relativity for T

  4. 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.

  5. 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.

  6. The role of spatial memory and frames of reference in the precision of angular path integration.

    Science.gov (United States)

    Arthur, Joeanna C; Philbeck, John W; Kleene, Nicholas J; Chichka, David

    2012-09-01

    Angular path integration refers to the ability to maintain an estimate of self-location after a rotational displacement by integrating internally-generated (idiothetic) self-motion signals over time. Previous work has found that non-sensory inputs, namely spatial memory, can play a powerful role in angular path integration (Arthur et al., 2007, 2009). Here we investigated the conditions under which spatial memory facilitates angular path integration. We hypothesized that the benefit of spatial memory is particularly likely in spatial updating tasks in which one's self-location estimate is referenced to external space. To test this idea, we administered passive, non-visual body rotations (ranging 40°-140°) about the yaw axis and asked participants to use verbal reports or open-loop manual pointing to indicate the magnitude of the rotation. Prior to some trials, previews of the surrounding environment were given. We found that when participants adopted an egocentric frame of reference, the previously-observed benefit of previews on within-subject response precision was not manifested, regardless of whether remembered spatial frameworks were derived from vision or spatial language. We conclude that the powerful effect of spatial memory is dependent on one's frame of reference during self-motion updating.

  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.

    2016-04-01

    SLR is the unique technique that allows determining the geocentre with very high accuracy and contributes to the realization of the scale of a conventional reference frame. In addition, due to the high sensitivity of the SLR-tracked satellites on the Earth's gravitational field, SLR is a crucial technique for determining important geodetic parameters such as Earth Orientation Parameters (EOP) and low-degree spherical harmonics of the Earth's gravitational field model. So far, the distribution of SLR stations has been quite inhomogeneous, especially in the southern hemisphere, mostly due to the lack of land-masses. With the set-up of a new SLR station in Brasilia in 2014 and the transfer of the former TIGO observatory from Concepción (Chile) to La Plata (Argentina) - now known as AGGO Argentinian-German Geodetic Observatory -, the shape of SLR subnetwork in South America has changed significantly. Furthermore, additional SLR stations in India (Mount Abu and Ponmundi), as well as a new station in Hartebeesthoek, are scheduled to start operations in 2016 and they will further improve the global SLR network geometry. In this work, SLR data has been simulated in order to determine the influence of the changing SLR network geometry on the geodetic parameters such as a global terrestrial reference frame, EOP and the low-degree harmonics of the Earth's gravitational field. The simulations have been performed for different network geometries as well as different satellites. In this investigation, a special emphasis is placed on the improvement of the geocentric realization of a global SLR-derived reference frame.

  8. Quantum reverse-engineering and reference frame alignment without non-local correlations

    CERN Document Server

    Bagán, E; Muñoz-Tàpia, R

    2004-01-01

    Estimation of unknown qubit elementary gates and alignment of reference frames are formally the same problem. Using quantum states made out of $N$ qubits, we show that the theoretical precision limit for both problems, which behaves as $1/N^{2}$, can be asymptotically attained with a covariant protocol that exploits the quantum correlation of internal degrees of freedom instead of the more fragile entanglement between distant parties. This cuts by half the number of qubits needed to achieve the precision of the dense covariant coding protocol.

  9. Residual sweeping effects in the swept frame of reference in Kinematic Simulations

    CERN Document Server

    Malik, Nadeem A

    2015-01-01

    It has been suggested that sweeping effects make Lagrangian properties in Kinematic Simulations (KS) unreliable. Here we show through a novel analysis based upon analysing neighbouring particle trajectories in a frame of reference moving with the large energy contining scales that the residual sweeping error in the turbulent pair diffusivity ($K$) in KS is $e_K\\sim dt/\\tau_s$, where $dt$ is the numerical timestep and $\\tau_s$ is the time scale of the sweeping through local eddies. Thus, provided that $dt\\ll \\tau_s$, then $e_K\\ll 1$ and the Lagrangian properties in KS are reliable.

  10. Entanglement assisted alignment of reference frames using a dense covariant coding

    CERN Document Server

    Bagán, E; Muñoz-Tàpia, R

    2003-01-01

    We present a procedure inspired by dense coding, which enables a highly efficient transmission of information of a continuous nature. The procedure requires the sender and the recipient to share a maximally entangled state. We deal with the concrete problem of aligning reference frames or trihedra by means of a quantum system. We find the optimal covariant measurement and compute the corresponding average error, which has a remarkably simple close form. The connection of this procedure with that of estimating unitary transformations on qubits is briefly discussed.

  11. 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...

  12. The Large Quasar Reference Frame (LQRF). An Optical Representation of the ICRS

    Science.gov (United States)

    2009-10-01

    found in the USNO B1.0 and GSC2.3 catalogs, and from the SDSS Data Release 5. The initial positions are next placed onto UCAC2-based reference frames...are found for all the catalogs used (apart from the SDSS DR5), an empirical magnitude correction can be discussed for the GSC2.3 intermediate and...right) of the quasars found in the LQAC catalog. The highest density regions indi- cate the SDSS DR5 contribution.The scale represents the number of

  13. Perfectly Matched Layer (PML) for Transient Wave Propagation in a Moving Frame of Reference

    DEFF Research Database (Denmark)

    Madsen, Stine Skov; Krenk, Steen; Hededal, Ole

    2013-01-01

    In relation to the development of a Rolling Wheel Deflectometer (RWD), which is a non-destructive testing device for measuring pavement deflections, a finite element model for obtaining the soil/pavement response is developed. Absorbing boundary conditions are necessary in order to prevent...... and a formulation in a moving mesh is therefore more convenient. In this paper, a formulation of the PML is developed in the moving frame of reference. Numerical results are presented for a single layer and a double layer half space, respectively, subjected to a moving load of different velocities....

  14. 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...... the original convolution integrals are represented via two auxiliary displacement-like state-space variables. A parametric study of the AML parameters is conducted for optimizing the absorbing properties. The performance is demonstrated on a single- and a two-layered half-space for various velocities...... of an impulse Ricker load. Excellent absorbing properties are demonstrated in both half spaces....

  15. New conceptions on the light wave theory in a moving frame of reference

    CERN Document Server

    Nascimento, Daniel Lima

    2013-01-01

    A reanalisis of the effect of a moving frame of reference is done, showing that the null result of the Michelson-Morley's experimente of 1887 on the possibility of detecting the variation of the velocity of light with respect to a moving observer, na observer at the Earth, was already implied in these equations; thereforewith no need of new ad hoc hypotheses to explain it in the classical framework. In fact, it will be shown that behind those equations is hidden the fascinating phenomenon of the absolute motion.

  16. Enhanced Decoupled Double Synchronous Reference Frame Current Controller for Unbalanced Grid-Voltage Conditions

    DEFF Research Database (Denmark)

    Reyes, M.; Rodriguez, Pedro; Vazquez, S.;

    2012-01-01

    . In these codes, the injection of positive- and negative-sequence current components becomes necessary for fulfilling, among others, the low-voltage ride-through requirements during balanced and unbalanced grid faults. However, the performance of classical dq current controllers, applied to power converters......, under unbalanced grid-voltage conditions is highly deficient, due to the unavoidable appearance of current oscillations. This paper analyzes the performance of the double synchronous reference frame controller and improves its structure by adding a decoupling network for estimating and compensating...

  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......-PLL as a filter or controller inside the closed-loop control systems. In this letter, the transfer function describing the actual inputoutput relationship of the conventional SRF-PLL is presented. Using this transfer function, it is shown that the conventional SRF-PLL is a first-order adaptive complex bandpass...

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

    Science.gov (United States)

    Richter-Was, E.; Was, Z.

    2017-02-01

    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 → ℓ ν 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 ^+ ℓ ^- 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_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.

  19. 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.

  20. Back action evading quantum measurement of motion in a negative mass reference frame

    CERN Document Server

    Møller, Christoffer B; Vasilakis, Georgios; Zeuthen, Emil; Tsaturyan, Yeghishe; Jensen, Kasper; Schliesser, Albert; Hammerer, Klemens; Polzik, Eugene S

    2016-01-01

    Quantum mechanics dictates that a measurement without perturbation is not possible. A textbook example is the observation of the position of an object, which imposes a random back action perturbation on the momentum. This randomness translates with time into position uncertainty, thus leading to the well known uncertainty on the measurement of motion. Here we demonstrate that the back action on an oscillator measured in a reference frame of another oscillator with an effective negative mass can be evaded in both position and momentum variables simultaneously. The mechanical oscillator is a millimeter-sized membrane and the reference negative mass oscillator is the collective spin of an atomic ensemble precessing in a magnetic field. Laser light transmitted through the hybrid system of these two disparate oscillators serves as the meter. We first observe the quantum measurement back action on each oscillator. We then demonstrate that back action at the single noise photon level is efficiently suppressed or enh...

  1. An anti-disturbance high-precision alignment for distributed POS based on inertial reference frame

    Science.gov (United States)

    Bai, Lijian; Wang, Yue

    2017-03-01

    The distributed POS is playing an important role in the ultra-high resolution aerial survey and remote sensing system, and can accurately provide time-spatial reference information for various imaging sensors. However, the distributed POS faces a special problem that the flexible arms used to connect the inertial measurement units (IMUs) would deteriorate the phenomenon that external disturbance leads to serious alignment errors. In order to improve the alignment precision of distributed POS in external disturbance, an anti-disturbance coarse alignment based on inertial reference frame is proposed. This method is developed mainly based on the structure of non-collinear vectors, which are constructed by a velocity vector determined by gravity vector integration. The disturbed acceleration and rotation is decreased a lot by the integral operation in the proposed method. Finally, the experiments were carried out and verified the validity of the proposed method.

  2. 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

    damping and improve both transient and steady-state performances, a voltage decoupling feedforward to improve the system robustness, and a multi-resonant harmonic compensator to prevent low-order load current harmonics to distort the inverter output voltage. Since, the voltage loop works......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...

  3. Determination of a terrestrial reference frame via Kalman filtering of very long baseline interferometry data

    Science.gov (United States)

    Soja, Benedikt; Nilsson, Tobias; Balidakis, Kyriakos; Glaser, Susanne; Heinkelmann, Robert; Schuh, Harald

    2016-12-01

    Terrestrial reference frames (TRF), such as the ITRF2008, are primary products of geodesy. In this paper, we present TRF solutions based on Kalman filtering of very long baseline interferometry (VLBI) data, for which we estimate steady station coordinates over more than 30 years that are updated for every single VLBI session. By applying different levels of process noise, non-linear signals, such as seasonal and seismic effects, are taken into account. The corresponding stochastic model is derived site-dependent from geophysical loading deformation time series and is adapted during periods of post-seismic deformations. Our results demonstrate that the choice of stochastic process has a much smaller impact on the coordinate time series and velocities than the overall noise level. If process noise is applied, tests with and without additionally estimating seasonal signals indicate no difference between the resulting coordinate time series for periods when observational data are available. In a comparison with epoch reference frames, the Kalman filter solutions provide better short-term stability. Furthermore, we find out that the Kalman filter solutions are of similar quality when compared to a consistent least-squares solution, however, with the enhanced attribute of being easier to update as, for instance, in a post-earthquake period.

  4. Determination of a terrestrial reference frame via Kalman filtering of very long baseline interferometry data

    Science.gov (United States)

    Soja, Benedikt; Nilsson, Tobias; Balidakis, Kyriakos; Glaser, Susanne; Heinkelmann, Robert; Schuh, Harald

    2016-06-01

    Terrestrial reference frames (TRF), such as the ITRF2008, are primary products of geodesy. In this paper, we present TRF solutions based on Kalman filtering of very long baseline interferometry (VLBI) data, for which we estimate steady station coordinates over more than 30 years that are updated for every single VLBI session. By applying different levels of process noise, non-linear signals, such as seasonal and seismic effects, are taken into account. The corresponding stochastic model is derived site-dependent from geophysical loading deformation time series and is adapted during periods of post-seismic deformations. Our results demonstrate that the choice of stochastic process has a much smaller impact on the coordinate time series and velocities than the overall noise level. If process noise is applied, tests with and without additionally estimating seasonal signals indicate no difference between the resulting coordinate time series for periods when observational data are available. In a comparison with epoch reference frames, the Kalman filter solutions provide better short-term stability. Furthermore, we find out that the Kalman filter solutions are of similar quality when compared to a consistent least-squares solution, however, with the enhanced attribute of being easier to update as, for instance, in a post-earthquake period.

  5. Estimation and Analysis of Parameters for Reference Frame Transformation%参考架转换参数估计与分析∗

    Institute of Scientific and Technical Information of China (English)

    杨廷高; 高玉平; 童明雷; 赵成仕; 高峰

    2016-01-01

    Based on the estimation method of parameters for reference frame transfor-mation, the parameters used for transformation between different modern DE (Develop-ment Ephemeris) ephemeris pairs are derived using the data of heliocentric coordinates of Earth-Moon barycenter from DE ephemeris pairs, and the transformation parameters between DE ephemeris dynamic reference frame and ICRF (International Celestial Ref-erence Frame) are estimated by using the timing data and VLBI (Very Long Baseline Interferometry) observation results of millisecond pulsars. The estimated parameters for the reference frame transformation include three rotational angles of rotational ma-trix and their derivatives of time. The reference epoch of estimated parameters for the reference frame transformation is MJD51545, that is J2000.0. Our results show that the absolute maximum value of rotational angles for the transformation of DE200 to DE405 ephemeris is 13 mas, and its derivative of time is−0.0007 mas/d. No absolute value of rotational angles is larger than 0.1 mas for the transformation of DE414 to DE421 ephemeris. The absolute maximum value of rotational angles of rotation matrix for the transformation of DE421 ephemeris to ICRF is 3 mas, and the time derivatives of three rotational angles are also necessarily included.%在描述不同参考架转换参数估计方法的基础上,利用太阳系行星历表资料估计了近代不同DE (Development Ephemeris)历表之间的转换参数;利用脉冲星计时观测与VLBI (Very Long Baseline Interferometry)技术观测得到的毫秒脉冲星位置资料,估计了基于DE历表的动力学参考架与河外射电源参考架(ICRF)之间的转换参数.给出的不同参考架之间转换参数包括旋转矩阵的3个旋转角及其随时间的变化率,参考历元为MJD51545.结果表明: DE200到DE405历表转换参数的旋转角最大绝对值为13 mas,其随时间变化率为−0.0007 mas/d. DE414到DE421历表转换参数的3个

  6. The International DORIS Service contribution to the 2014 realization of the International Terrestrial Reference Frame

    Science.gov (United States)

    Moreaux, Guilhem; Lemoine, Frank G.; Capdeville, Hugues; Kuzin, Sergey; Otten, Michiel; Štěpánek, Petr; Willis, Pascal; Ferrage, Pascale

    2016-12-01

    In preparation of the 2014 realization of the International Terrestrial Reference Frame (ITRF2014), the International DORIS Service delivered to the International Earth Rotation and Reference Systems Service a set of 1140 weekly solution files including station coordinates and Earth orientation parameters, covering the time period from 1993.0 to 2015.0. The data come from eleven DORIS satellites: TOPEX/Poseidon, SPOT2, SPOT3, SPOT4, SPOT5, Envisat, Jason-1, Jason-2, Cryosat-2, Saral and HY-2A. In their processing, the six analysis centers which contributed to the DORIS combined solution used the latest time variable gravity models and estimated DORIS ground beacon frequency variations. Furthermore, all the analysis centers but one excepted included in their processing phase center variations for ground antennas. The main objective of this study is to present the combination process and to analyze the impact of the new modeling on the performance of the new combined solution. Comparisons with the IDS contribution to ITRF2008 show that (i) the application of the DORIS ground phase center variations in the data processing shifts the combined scale upward by nearly 7-11 mm and (ii) thanks to estimation of DORIS ground beacon frequency variations, the new combined solution no longer shows any scale discontinuity in early 2002 and does not present unexplained vertical discontinuities in any station position time series. However, analysis of the new series with respect to ITRF2008 exhibits a scale increase late 2011 which is not yet explained. A new DORIS Terrestrial Reference Frame was computed to evaluate the intrinsic quality of the new combined solution. That evaluation shows that the addition of data from the new missions equipped with the latest generation of DORIS receiver (Jason-2, Cryosat-2, HY-2A, Saral), results in an internal position consistency of 10 mm or better after mid-2008.

  7. Quantum Space-Time and Reference Frames in Gravity and Flat Space-Time

    CERN Document Server

    Mayburov, S

    2000-01-01

    The quantum space-time model which accounts material Reference Frames (RF) quantum effects considered for flat space-time and ADM canonical gravity. As was shown by Aharonov for RF - free material object its c.m. nonrelativistic motion in vacuum described by Schrodinger wave packet evolution which modify space coordinate operator of test particle in this RF and changes its Heisenberg uncertainty relations. In the relativistic case we show that Lorentz transformations between two RFs include the quantum corrections for RFs momentum uncertainty and in general can be formulated as the quantum space-time transformations. As the result for moving RF its Lorentz time boost acquires quantum fluctuations which calculated solving relativistic Heisenberg equations for the quantum clocks models. It permits to calculate RF proper time for the arbitrary RF quantum motion including quantum gravity metrics fluctuations. Space-time structure of canonical Quantum Gravity and its observables evolution for RF proper time discus...

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

    Science.gov (United States)

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

    2013-07-01

    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.

  9. The reference frame of visual motion priming depends on underlying motion mechanisms.

    Science.gov (United States)

    Yoshimoto, Sanae; Uchida-Ota, Mariko; Takeuchi, Tatsuto

    2014-01-10

    Several different types of motion mechanisms function in the human visual system. The purpose of this study was to clarify the type of reference frame, such as retinotopic and spatiotopic frames of reference, at which those different motion mechanisms function. To achieve this, we used a phenomenon called visual motion priming, in which the perceived direction of a directionally ambiguous test stimulus is influenced by the moving direction of a preceding stimulus. Previous studies have indicated that negative motion priming is induced by a low-level motion mechanism, such as a first-order motion sensor, whereas positive motion priming is induced by a high-level motion mechanism, such as a feature-tracking system. In the experiments, subjects made a saccade after the termination of a smoothly drifting priming stimulus and judged the perceived direction of a 180° phase-shifted sine-wave grating presented subsequently in retinotopic or screen-based spatiotopic coordinates. By manipulating the stimulus parameters, such as primer duration, velocity, and contrast, both positive and negative priming were observed. We found that positive priming was observed in spatiotopic coordinates, whereas negative priming was observed in retinotopic coordinates. Prominent positive priming in spatiotopic coordinates was observed only when the interval between the priming and test stimuli was longer than around 600 ms. This delayed priming effect was not caused by saccadic eye movements. These results suggest that a low-level motion mechanism functions in retinotopic coordinates, whereas a high-level motion mechanism functions in spatiotopic coordinates, in which the representation builds up slowly.

  10. ITRF2014: A new release of the International Terrestrial Reference Frame modeling nonlinear station motions

    Science.gov (United States)

    Altamimi, Zuheir; Rebischung, Paul; Métivier, Laurent; Collilieux, Xavier

    2016-08-01

    For the first time in the International Terrestrial Reference Frame (ITRF) history, the ITRF2014 is generated with an enhanced modeling of nonlinear station motions, including seasonal (annual and semiannual) signals of station positions and postseismic deformation for sites that were subject to major earthquakes. Using the full observation history of the four space geodetic techniques (very long baseline interferometry (VLBI), satellite laser ranging (SLR), Global Navigation Satellite Systems (GNSS), and Doppler orbitography and radiopositioning integrated by satellite (DORIS)), the corresponding international services provided reprocessed time series (weekly from SLR and DORIS, daily from GNSS, and 24 h session-wise from VLBI) of station positions and daily Earth Orientation Parameters. ITRF2014 is demonstrated to be superior to past ITRF releases, as it precisely models the actual station trajectories leading to a more robust secular frame and site velocities. The ITRF2014 long-term origin coincides with the Earth system center of mass as sensed by SLR observations collected on the two LAGEOS satellites over the time span between 1993.0 and 2015.0. The estimated accuracy of the ITRF2014 origin, as reflected by the level of agreement with the ITRF2008 (both origins are defined by SLR), is at the level of less than 3 mm at epoch 2010.0 and less than 0.2 mm/yr in time evolution. The ITRF2014 scale is defined by the arithmetic average of the implicit scales of SLR and VLBI solutions as obtained by the stacking of their respective time series. The resulting scale and scale rate differences between the two solutions are 1.37 (±0.10) ppb at epoch 2010.0 and 0.02 (±0.02) ppb/yr. While the postseismic deformation models were estimated using GNSS/GPS data, the resulting parametric models at earthquake colocation sites were applied to the station position time series of the three other techniques, showing a very high level of consistency which enforces more the link

  11. Reference frames in allocentric representations are invariant across static and active encoding

    Directory of Open Access Journals (Sweden)

    Edgar eChan

    2013-08-01

    Full Text Available An influential model of spatial memory – the so-called reference systems account – proposes that relationships between objects are biased by salient axes (frames of reference provided by environmental cues, such as the geometry of a room. In this study, we sought to examine the extent to which a salient environmental feature influences the formation of spatial memories when learning occurs via a single, static viewpoint and via active navigation, where information has to be integrated across multiple viewpoints. In our study, participants learned the spatial layout of an object array that was arranged with respect to a prominent environmental feature within a virtual arena. Location memory was tested using judgements of relative direction. Experiment 1a employed a design similar to previous studies whereby learning of object-location information occurred from a single, static viewpoint. Consistent with previous studies, spatial judgments were significantly more accurate when made from an orientation that was aligned, as opposed to misaligned, with the salient environmental feature. In Experiment 1b, a fresh group of participants learned the same object-location information through active exploration, which required integration of spatial information over time from a ground-level perspective. As in Experiment 1a, object-location information was organized around the salient environmental cue. Taken together, the findings suggest that the learning condition (static vs. active does not affect the reference system employed to encode object-location information. Spatial reference systems appear to be a ubiquitous property of spatial representations, and might serve to reduce the cognitive demands of spatial processing.

  12. 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.

  13. On applying the extended intrinsic mean spin tensor to modelling the turbulence in non-inertial frames of reference

    Institute of Scientific and Technical Information of China (English)

    HUANG YuNing; MA HuiYang; XU JingLei

    2008-01-01

    Modelling the turbulent flows in non-inertial frames of reference has long been a challenging task. Recently we introduced the notion of the "extended intrinsic mean spin tensor" for turbulence modelling and pointed out that, when applying the Reynolds stress models developed in the inertial frame of reference to model-ling the turbulence in a non-inertial frame of reference, the mean spin tensor should be replaced by the extended intrinsic mean spin tensor to correctly account for the rotation effects induced by the non-inertial frame of reference, to conform in phys-ics with the Reynolds stress transport equation. To exemplify the approach, we conducted numerical simulations of the fully developed turbulent channel flow in a rotating frame of reference by employing four non-linear K-εmodels. Our numerical results based on this approach at a wide range of Reynolds and Rossby numbers evince that, among the models tested, the non-linear K-ε model of Huang and Ma and the non-linear K-ε model of Craft, Launder and Suga can better capture the rotation effects and the resulting influence on the structures of turbulence, and therefore are satisfactorily applied to dealing with the turbulent flows of practical interest in engineering. The general approach worked out in this paper is also ap-plied to the second-moment closure and the large-eddy simulation of turbulence.

  14. On applying the extended intrinsic mean spin tensor to modelling the turbulence in non-inertial frames of reference

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Modelling the turbulent flows in non-inertial frames of reference has long been a challenging task. Recently we introduced the notion of the "extended intrinsic mean spin tensor" for turbulence modelling and pointed out that, when applying the Reynolds stress models developed in the inertial frame of reference to model-ling the turbulence in a non-inertial frame of reference, the mean spin tensor should be replaced by the extended intrinsic mean spin tensor to correctly account for the rotation effects induced by the non-inertial frame of reference, to conform in phys-ics with the Reynolds stress transport equation. To exemplify the approach, we conducted numerical simulations of the fully developed turbulent channel flow in a rotating frame of reference by employing four non-linear K-ε models. Our numerical results based on this approach at a wide range of Reynolds and Rossby numbers evince that, among the models tested, the non-linear K-ε model of Huang and Ma and the non-linear K-ε model of Craft, Launder and Suga can better capture the rotation effects and the resulting influence on the structures of turbulence, and therefore are satisfactorily applied to dealing with the turbulent flows of practical interest in engineering. The general approach worked out in this paper is also ap-plied to the second-moment closure and the large-eddy simulation of turbulence.

  15. Flow of a Dusty Gas with Suspended Particles in a Rotating Frame of Reference

    Directory of Open Access Journals (Sweden)

    P. Mitra

    1981-01-01

    Full Text Available The solution is given for the problem on the motion of a dusty gas under a rotating system of co-ordinates. The gas containing a uniform distribution of dust particles, occupies the infinite space above a rigid plane boundary. The motion of the dusty gas is induced by the motion of the plate moving with a velocity which decreases exponentially with time in a rotating frame of reference such that the plate and the gas are in a state of rigid body rotation about an axis normal to the plate. The velocity fields for the dusty gas, and the dust particles along and normal to the direction of motion of the plate are obtained in closed forms. Finally, some velocity distributions are calculated with particular reference to the effect of rotation at different times, and it is found that with the increase of the value of the rotation parameter omega, the velocity of the dusty gas along the direction of motion of the plate gradually increases while the velocity of the dust particle along the same direction gradually decreases.

  16. The Two-Wrongs model explains perception-action dissociations for illusions driven by distortions of the egocentric reference frame

    Directory of Open Access Journals (Sweden)

    Paul eDassonville

    2015-03-01

    Full Text Available Several studies have demonstrated a dissociation of the effects of illusion on perception and action, with perception generally reported to be susceptible to illusions, while actions are seemingly immune. These findings have been interpreted to support Milner and Goodale's Two Visual Systems model, which proposes the existence of separate visual processing streams for perception and action. However, an alternative interpretation suggests that this type of behavioral dissociation will occur for any illusion that is caused by a distortion of the observer's egocentric reference frame, without requiring the existence of separate perception and action systems that are differently affected by the illusion. In this scenario, movements aimed at illusory targets will be accurate if they are guided within the same distorted reference frame used for target encoding, since the error of motor guidance will cancel with the error of encoding (hence, for actions, two wrongs do make a right. We further test this Two-Wrongs model by examining two illusions for which the hypothesis makes very different predictions: the rod-and-frame illusion (which affects perception but not actions and the simultaneous-tilt illusion (which affects perception and actions equally. We demonstrate that the rod-and-frame illusion is caused by a distortion of the observer's egocentric reference frame suitable for the cancellation of errors predicted by the Two-Wrongs model. In contrast, the simultaneous-tilt illusion is caused by local interactions between stimulus elements within an undistorted reference frame, precluding the cancellation of errors associated with the Two-Wrongs model such that the illusion is reflected in both perception and actions. These results provide evidence for a class of illusions that lead to dissociations of perception and action through distortions of the observer's spatial reference frame, rather than through the actions of functionally separate visual

  17. Reference frame preferences in haptics differ for the blind and sighted in the horizontal but not in the vertical plane.

    Science.gov (United States)

    Struiksma, Marijn E; Noordzij, Matthijs L; Postma, Albert

    2011-01-01

    We investigated which reference frames are preferred when matching spatial language to the haptic domain. Sighted, low-vision, and blind participants were tested on a haptic-sentence-verification task where participants had to haptically explore different configurations of a ball and a shoe and judge the relation between them. Results from the spatial relation "above", in the vertical plane, showed that various reference frames are available after haptic inspection of a configuration. Moreover, the pattern of results was similar for all three groups and resembled patterns found for the sighted on visual sentence-verification tasks. In contrast, when judging the spatial relation "in front", in the horizontal plane, the blind showed a markedly different response pattern. The sighted and low-vision participants did not show a clear preference for either the absolute/relative or the intrinsic reference frame when these frames were dissociated. The blind, on the other hand, showed a clear preference for the intrinsic reference frame. In the absence of a dominant cue, such as gravity in the vertical plane, the blind might emphasise the functional relationship between the objects owing to enhanced experience with haptic exploration of objects.

  18. Impact of uncertain reference-frame motions in plate kinematic reconstructions: A theoretical appraisal

    Science.gov (United States)

    Iaffaldano, Giampiero; Stein, Seth

    2017-01-01

    Geoscientists infer past plate motions, which serve as fundamental constraints for a range of studies, from observations of magnetic isochrons as well as hotspots tracks on the ocean floor and, for stages older than the Cretaceous, from paleomagnetic data. These observations effectively represent time-integrals of past plate motions but, because they are made at present, yield plate kinematics naturally tied to a present-day reference-frame, which may be another plate or a hotspots system. These kinematics are therefore different than those occurred at the time when the rocks acquired their magnetisation or when hotspot-related marine volcanism took place, and are normally corrected for the reference-frame absolute motion (RFAM) that occurred since then. The impact of true-polar-wander events on paleomagnetic data and the challenge of inferring hotspot drifts result in RFAMs being less resolved - in a temporal sense - and prone to noise. This limitation is commonly perceived to hamper the correction of plate kinematic reconstructions for RFAMs, but the extent to which this may be the case has not been explored. Here we assess the impact of uncertain RFAMs on kinematic reconstructions using synthetic models of plate motions over 100 million years. We use randomly-drawn models for the kinematics of two plates separated by a spreading ridge to generate a synthetic magnetisation pattern of the ocean floor. The kinematics we infer from such a pattern are outputs that we correct for synthetic RFAMs using two equivalent methods (a classical one as well as another that we propose and test here) and then compare to the 'true' motions input. We assess the misfits between true and inferred kinematics by exploring a statistically-significant number of models where we systematically downgrade the temporal resolution of RFAM synthetic data and add noise to them. We show that even poorly-resolved, noisy RFAMs are sufficient to retrieve reliable plate kinematic reconstructions

  19. 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...... network to a standard SRF-PLL in order to effectively separate the positive- and negative-sequence voltage components in a fast and accurate way. Experimental evaluation of the proposed grid synchronization method and simulations regarding its application to ride through transient faults verify...

  20. The right frame of reference makes it simple: an example of introductory mechanics supported by video analysis of motion

    Science.gov (United States)

    Klein, P.; Gröber, S.; Kuhn, J.; Fleischhauer, A.; Müller, A.

    2015-01-01

    The selection and application of coordinate systems is an important issue in physics. However, considering different frames of references in a given problem sometimes seems un-intuitive and is difficult for students. We present a concrete problem of projectile motion which vividly demonstrates the value of considering different frames of references. We use this example to explore the effectiveness of video-based motion analysis (VBMA) as an instructional technique at university level in enhancing students’ understanding of the abstract concept of coordinate systems. A pilot study with 47 undergraduate students indicates that VBMA instruction improves conceptual understanding of this issue.

  1. The geometry of celestial mechanics

    CERN Document Server

    Geiges, Hansjörg

    2016-01-01

    Celestial mechanics is the branch of mathematical astronomy devoted to studying the motions of celestial bodies subject to the Newtonian law of gravitation. This mathematical introductory textbook reveals that even the most basic question in celestial mechanics, the Kepler problem, leads to a cornucopia of geometric concepts: conformal and projective transformations, spherical and hyperbolic geometry, notions of curvature, and the topology of geodesic flows. For advanced undergraduate and beginning graduate students, this book explores the geometric concepts underlying celestial mechanics and is an ideal companion for introductory courses. The focus on the history of geometric ideas makes it perfect supplementary reading for students in elementary geometry and topology. Numerous exercises, historical notes and an extensive bibliography provide all the contextual information required to gain a solid grounding in celestial mechanics.

  2. 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.

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

    CERN Document Server

    Germana, Claudio

    2012-01-01

    Recent results from the OPERA experiment reported a neutrino beam traveling faster than light. The experiment measured the neutrino time of flight (TOF) over a baseline from the CERN to the Gran Sasso site. The neutrino beam arrives 60 ns earlier than a light ray would do. Because the result 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. 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 Solar System Barycenter(SSB). The Tempo2 software was used to time-stamp events observed on the geoid with respect to the SSB inertial observer time. Neutrino results from OPERA might carry the fingerprint of non-inertial effects. The CERN-Gran Sasso clock synchronizatio...

  4. Force encoding in stick insect legs delineates a reference frame for motor control.

    Science.gov (United States)

    Zill, Sasha N; Schmitz, Josef; Chaudhry, Sumaiya; Büschges, Ansgar

    2012-09-01

    The regulation of forces is integral to motor control. However, it is unclear how information from sense organs that detect forces at individual muscles or joints is incorporated into a frame of reference for motor control. Campaniform sensilla are receptors that monitor forces by cuticular strains. We studied how loads and muscle forces are encoded by trochanteral campaniform sensilla in stick insects. Forces were applied to the middle leg to emulate loading and/or muscle contractions. Selective sensory ablations limited activities recorded in the main leg nerve to specific receptor groups. The trochanteral campaniform sensilla consist of four discrete groups. We found that the dorsal groups (Groups 3 and 4) encoded force increases and decreases in the plane of movement of the coxo-trochanteral joint. Group 3 receptors discharged to increases in dorsal loading and decreases in ventral load. Group 4 showed the reverse directional sensitivities. Vigorous, directional responses also occurred to contractions of the trochanteral depressor muscle and to forces applied at the muscle insertion. All sensory discharges encoded the amplitude and rate of loading or muscle force. Stimulation of the receptors produced reflex effects in the depressor motoneurons that could reverse in sign during active movements. These data, in conjunction with findings of previous studies, support a model in which the trochanteral receptors function as an array that can detect forces in all directions relative to the intrinsic plane of leg movement. The array could provide requisite information about forces and simplify the control and adaptation of posture and walking.

  5. 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

  6. Asymmetric Learning Transfer between Imagined Viewer- and Object-Rotations: Evidence of a Hierarchical Organization of Spatial Reference Frames

    Science.gov (United States)

    Pellizzer, Giuseppe; Ba, Maryse Badan; Zanello, Adriano; Merlo, Marco C. G.

    2009-01-01

    Neural resources subserving spatial processing in either egocentric or allocentric reference frames are, at least partly, dissociated. However, it is unclear whether these two types of representations are independent or whether they interact. We investigated this question using a learning transfer paradigm. The experiment and material were…

  7. 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…

  8. 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…

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

    Science.gov (United States)

    Brunner, Martin; Ludtke, 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…

  10. 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…

  11. Reference Frames and 3-D Shape Perception of Pictured Objects: On Verticality and Viewpoint-From-Above.

    Science.gov (United States)

    Cornelis, Els V K; van Doorn, Andrea J; Wagemans, Johan

    2016-05-01

    Research on the influence of reference frames has generally focused on visual phenomena such as the oblique effect, the subjective visual vertical, the perceptual upright, and ambiguous figures. Another line of research concerns mental rotation studies in which participants had to discriminate between familiar or previously seen 2-D figures or pictures of 3-D objects and their rotated versions. In the present study, we disentangled the influence of the environmental and the viewer-centered reference frame, as classically done, by comparing the performances obtained in various picture and participant orientations. However, this time, the performance is the pictorial relief: the probed 3-D shape percept of the depicted object reconstructed from the local attitude settings of the participant. Comparisons between the pictorial reliefs based on different picture and participant orientations led to two major findings. First, in general, the pictorial reliefs were highly similar if the orientation of the depicted object was vertical with regard to the environmental or the viewer-centered reference frame. Second, a viewpoint-from-above interpretation could almost completely account for the shears occurring between the pictorial reliefs. More specifically, the shears could largely be considered as combinations of slants generated from the viewpoint-from-above, which was determined by the environmental as well as by the viewer-centered reference frame.

  12. 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.

  13. 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 negotiation…

  14. 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....

  15. Supercontinent Pangea, Mantle Dynamics, and Reference Frame of Global Plate Motions

    Science.gov (United States)

    Zhong, S.; Rudolph, M. L.; Liu, X.

    2014-12-01

    Arguably the most important and challenging goal in geodynamics is to understand the two-way dynamics between tectonic plates and mantle convection. While it has long been recognized that the present-day degree-2 mantle structure as imaged seismically is closely related to the plate motions (Hager and O'Connell, 1981) and their history (500 Ma (Torsvik et al., 2014), although its statistical significance has been challenged (Austermann et al., 2013). The proposals of the spatially stable Africa and Pacific LLSVPs and of the LIP eruptions along their edges have also been exploited in attempts to build global plate motion models since the Pangea assembly by providing a plate motion reference frame or inferring true polar wander (TPW) corrections to the plate motions (Torsvik et al., 2014). Second, mantle dynamics studies indicate that degree-1 mantle convection, which is expected with realistic lithospheric and mantle viscosity, may be needed for assembly of a supercontinent (e.g., Pangea) (Zhong et al., 2007). This suggests that the present degree-2 mantle structure may have been formed only after the Pangea assembly from an initially degree-1 structure - a scenario that is consistent with convection calculations with a proxy plate motion model that considers Pangea process (Zhang et al., 2010). In this presentation, in addition to critically reviewing these arguments, we will discuss calculations of long-wavelength geoid for the mantle with thermochemical piles and LLSVPs and their potential effects on TPW determinations and hence reconstruction of plate motion (i.e., net lithospheric rotation). We will also present additional calculations of mantle structure evolution using different plate motion history models.

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

    Directory of Open Access Journals (Sweden)

    Gerdi Mulder

    2013-01-01

    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.

  17. 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

  18. GPS-derived ground deformation (2005-2014) within the Gulf of Mexico region referred to a stable Gulf of Mexico reference frame

    Science.gov (United States)

    Yu, Jiangbo; Wang, Guoquan

    2016-07-01

    This study investigates current ground deformation derived from the GPS geodesy infrastructure in the Gulf of Mexico region. The positions and velocity vectors of 161 continuous GPS (CGPS) stations are presented with respect to a newly established local reference frame, the Stable Gulf of Mexico Reference Frame (SGOMRF). Thirteen long-term (> 5 years) CGPS are used to realize the local reference frame. The root mean square (RMS) of the velocities of the 13 SGOMRF reference stations achieves 0.2 mm yr-1 in the horizontal and 0.3 mm yr-1 in the vertical directions. GPS observations presented in this study indicate significant land subsidence in the coastal area of southeastern Louisiana, the greater Houston metropolitan area, and two cities in Mexico (Aguascalientes and Mexico City). The most rapid subsidence is recorded at the Mexico City International airport, which is up to 26.6 cm yr-1 (2008-2014). Significant spatial variation of subsidence rates is observed in both Mexico City and the Houston area. The overall subsidence rate in the Houston area is decreasing. The subsidence rate in southeastern Louisiana is relatively smaller (4.0-6.0 mm yr-1) but tends to be steady over time. This poses a potential threat to the safety of coastal infrastructure in the long-term.

  19. GPS derived ground motions (2005–2014 within the Gulf of Mexico region referred to a stable Gulf of Mexico reference frame

    Directory of Open Access Journals (Sweden)

    J. Yu

    2015-11-01

    Full Text Available This study investigates current ground motions derived from the GPS geodesy infrastructure in the Gulf of Mexico region. The positions and velocity vectors of 161 continuous GPS (CGPS stations are presented with respect to a newly established local reference frame, the Stable Gulf of Mexico Reference Frame (SGOMRF. Thirteen long-term (> 5 years CGPS are used to realize the local reference frame. The root-mean-square (RMS of the velocities of the 13 SGOMRF reference stations achieves 0.2 mm yr−1 in the horizontal and 0.3 mm yr−1 in the vertical directions. GPS observations presented in this study indicate significant land subsidence in the coastal area of southeastern Louisiana, the greater Houston metropolitan area, and two cities in Mexico (Aguascalientes and Mexico City. The most rapid subsidence is recorded at the Mexico City International airport, which is up to 26.6 cm yr−1 (2008–2014. Significant spatial variation of subsidence rates is observed in both Mexico City and the Houston area. The overall subsidence rate in the Houston area is decreasing. GPS observations in southeastern Louisiana indicate minor (4.0–6.0 mm yr−1 but consistent subsidence over time and space. This poses a potential threat to the safety of costal infrastructure in the long-term.

  20. 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.

  1. The Celestial Basis of Civilization

    Science.gov (United States)

    Masse, W. B.

    Scholars have long puzzled over the reasons for the ubiquity of celestial images in the residue of the world's earliest civilizations: in art, myth, religious cosmology, iconography, cosmogony, eschatological beliefs, and as portents for the conduct of royal and chiefly power. The general consensus is that these images represented a need by early societies to use the fixed celestial heavens in order to regulate ritual and agricultural cycles, and to satisfy a psychological need by people to relate themselves to their surrounding Universe. Such explanations are facile and miss an important aspect of the celestial heavens. The fixed celestial heavens served as the back-drop for a large number of often spectacular temporary naked-eye visible celestial events which animated the night and sometimes the daytime sky, and which created an 'otherworld' for virtually all cultural groups. In this paper I present a model derived from the detailed analysis of Hawaiian oral traditions and culture history in relation to historic astronomical records of temporary celestial events, and then apply this model to cultural traditions from Mesoamerica and other geographic regions in order to demonstrate that novae, supernovae, variable stars, comets, great meteor showers, aurorae, solar and lunar eclipses, and impacting Solar System debris, together played a critical role in the artistic, intellectual, and political development of early civilizations. These data not only provide important insights into the development of civilization, but also provide important details and longitudinal records of astronomical events and phenomena which are otherwise not readily available for scientific scrutiny.

  2. Face-infringement space: the frame of reference of the ventral intraparietal area.

    Science.gov (United States)

    McCollum, Gin; Klam, François; Graf, Werner

    2012-07-01

    Experimental studies have shown that responses of ventral intraparietal area (VIP) neurons specialize in head movements and the environment near the head. VIP neurons respond to visual, auditory, and tactile stimuli, smooth pursuit eye movements, and passive and active movements of the head. This study demonstrates mathematical structure on a higher organizational level created within VIP by the integration of a complete set of variables covering face-infringement. Rather than positing dynamics in an a priori defined coordinate system such as those of physical space, we assemble neuronal receptive fields to find out what space of variables VIP neurons together cover. Section 1 presents a view of neurons as multidimensional mathematical objects. Each VIP neuron occupies or is responsive to a region in a sensorimotor phase space, thus unifying variables relevant to the disparate sensory modalities and movements. Convergence on one neuron joins variables functionally, as space and time are joined in relativistic physics to form a unified spacetime. The space of position and motion together forms a neuronal phase space, bridging neurophysiology and the physics of face-infringement. After a brief review of the experimental literature, the neuronal phase space natural to VIP is sequentially characterized, based on experimental data. Responses of neurons indicate variables that may serve as axes of neural reference frames, and neuronal responses have been so used in this study. The space of sensory and movement variables covered by VIP receptive fields joins visual and auditory space to body-bound sensory modalities: somatosensation and the inertial senses. This joining of allocentric and egocentric modalities is in keeping with the known relationship of the parietal lobe to the sense of self in space and to hemineglect, in both humans and monkeys. Following this inductive step, variables are formalized in terms of the mathematics of graph theory to deduce which

  3. New VLBI2010 scheduling strategies and implications on the terrestrial reference frames.

    Science.gov (United States)

    Sun, Jing; Böhm, Johannes; Nilsson, Tobias; Krásná, Hana; Böhm, Sigrid; Schuh, Harald

    In connection with the work for the next generation VLBI2010 Global Observing System (VGOS) of the International VLBI Service for Geodesy and Astrometry, a new scheduling package (Vie_Sched) has been developed at the Vienna University of Technology as a part of the Vienna VLBI Software. In addition to the classical station-based approach it is equipped with a new scheduling strategy based on the radio sources to be observed. We introduce different configurations of source-based scheduling options and investigate the implications on present and future VLBI2010 geodetic schedules. By comparison to existing VLBI schedules of the continuous campaign CONT11, we find that the source-based approach with two sources has a performance similar to the station-based approach in terms of number of observations, sky coverage, and geodetic parameters. For an artificial 16 station VLBI2010 network, the source-based approach with four sources provides an improved distribution of source observations on the celestial sphere. Monte Carlo simulations yield slightly better repeatabilities of station coordinates with the source-based approach with two sources or four sources than the classical strategy. The new VLBI scheduling software with its alternative scheduling strategy offers a promising option with respect to applications of the VGOS.

  4. 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......-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...

  5. 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

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

    CERN Document Server

    Richter-Was, E

    2016-01-01

    Precision tests of the Standard Model in the Strong and Electroweak sectors play an important role, among the physics goals of LHC experiments. Because of the nature of proton-proton processes, observables based on the measurement of the direction and energy of leptons provide the most precise signatures. In the present paper, we concentrate on the angular distribution of leptons from W to l nu 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 polynomials 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 in the final state of neutrino escaping detection. There is thus no principle difference with respect to the phenomenology of the Z/gamma to l^+ l^- Drell-Yan process. We show also, that with the proper choice of the coordinate frames, only one coefficient in this p...

  7. 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.

  8. Fixing the Reference Frame for PPMXL Proper Motions Using Extragalactic Sources

    CERN Document Server

    Grabowski, Kathleen; Newberg, Heidi Jo; Beers, Timothy C; Chen, Li; Deng, Licai; Grillmair, Carl J; Guhathakurta, Puragra; Hou, Jinliang; Lepine, Sebastien; Liu, Chao; Liu, Xiaowei; Luo, A-Li; Smith, Martin C; Yanny, Brian; Zhang, Haotong; Zheng, Zheng

    2014-01-01

    We quantify and correct systematic errors in PPMXL proper motions using extragalactic sources from the first two LAMOST data releases and the Veron-Cetty & Veron Catalog of Quasars. Although the majority of the sources are from the Veron catalog, LAMOST makes important contributions in regions that are not well-sampled by previous catalogs, particularly at low Galactic latitudes and in the south Galactic cap. We show that quasars in PPMXL have measureable and significant proper motions, which reflect the systematic zero-point offsets present in the catalog. We confirm the global proper motion shifts seen by Wu, Ma, & Zhou (2011), and additionally find smaller-scale fluctuations of the QSO-derived corrections to an absolute frame. We average the proper motions of 158,106 extragalactic objects in bins of 3x3 degrees and present a table of proper motion corrections.

  9. Modular neuron-based body estimation: Maintaining consistency over different limbs, modalities, and frames of reference.

    Directory of Open Access Journals (Sweden)

    Stephan eEhrenfeld

    2013-10-01

    Full Text Available This paper addresses the question of how the brain may maintain a probabilistic body state estimate over time from a modeling perspective.The neural Modular Modality Frame (nMMF model simulates such a body state estimation process by continuously integrating redundant, multimodal body state information sources.The body state estimate itself is distributed over separate, but bidirectionally interacting modules.nMMF compares the incoming sensory and present body state information across the interacting modules and fuses the information sources accordingly. At the same time, nMMF enforces body state estimation consistency across the modules.nMMF is able to detect conflicting sensory information and to consequently decrease the influence of implausible sensor sources on the fly. In contrast to the previously published Modular Modality Frame (MMF model, nMMF offers a biologically plausible neural implementation based on distributed, probabilistic population codes. Besides its neural plausibility, the neural encoding has the advantage of enabling (a additional probabilistic information flow across the separate body state estimation modules and (b the representation of arbitrary probability distributions of a body state.The results show that the neural estimates can detect and decrease the impact of false sensory information, can propagate conflicting information across modules, and can improve overal estimation accuracy due to additional module interactions. Even bodily illusions, such as the rubber hand illusion, can be simulated with nMMF. We conclude with an outlook on the potential of modeling human data and of invoking goal-directed behavioral control.

  10. Differences in lower limb transverse plane joint moments during gait when expressed in two alternative reference frames.

    Science.gov (United States)

    Schache, Anthony G; Baker, Richard; Vaughan, Christopher L

    2007-01-01

    When comparing previous studies that have measured the three-dimensional moments acting about the lower limb joints (either external moments or opposing internal joint moments) during able-bodied adult gait, significant variation is apparent in the profiles of the reported transverse plane moments. This variation cannot be explained on the basis of adopted convention (i.e. external versus internal joint moment) or inherent variability in gait strategies. The aim of the current study was to determine whether in fact the frame in which moments are expressed has a dominant effect upon transverse plane moments and thus provides a valid explanation for the observed inconsistency in the literature. Kinematic and ground reaction force data were acquired from nine able-bodied adult subjects walking at a self-selected speed. Three-dimensional hip, knee and ankle joint moments during gait were calculated using a standard inverse dynamics approach. In addition to calculating internal joint moments, the components of the external moment occurring in the transverse plane at each of the lower limb joints were calculated to determine their independent effects. All moments were expressed in both the laboratory frame (LF) as well as the anatomical frame (AF) of the distal segment. With the exception of the ankle rotation moment in the foot AF, lower limb transverse plane joint moments during gait were found to display characteristic profiles that were consistent across subjects. Furthermore, lower limb transverse plane joint moments during gait differed when expressed in the distal segment AF compared to the LF. At the hip, the two alternative reference frames produced near reciprocal joint moment profiles. The components of the external moment revealed that the external ground reaction force moment was primarily responsible for this result. Lower limb transverse plane joint moments during gait were therefore found to be highly sensitive to a change in reference frame. These

  11. 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.

  12. 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.

  13. Non-iterative coherent diffractive imaging using a phase-shifting reference frame

    Energy Technology Data Exchange (ETDEWEB)

    Enders, B; Giewekemeyer, K; Salditt, T [Institut fuer Roentgenphysik, Universitaet Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany); Kurz, T [III. Physikalisches Institut, Universitaet Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany); Podorov, S [School of Physics, Monash University, Victoria 3800 (Australia)], E-mail: tsaldit@gwdg.de

    2009-04-15

    Lensless imaging is a high potential and currently intensely targeted research goal, in view of those fields of applications for which aberration-free high-resolution lenses are not available, for example for x-ray imaging. A recently proposed (direct inversion) variant of lensless imaging combines the advantages of two classical routes toward lensless imaging, the high-resolution characteristics of iterative object reconstruction, and the direct and deterministic nature of holographic reconstruction. Here, we use a simple standard optical setup using visible wavelength, a lithographic test object and a phase-shifting reference object to demonstrate the approach. Importantly, we show that a phase-shifting reference object, instead of the absorption mask proposed earlier, is sufficient for object reconstruction. This is relevant in view of the much easier implementation in future x-ray applications.

  14. Study and Analysis of a Natural Reference Frame Current Controller for a Multi-Level H-Bridge Power Converter

    DEFF Research Database (Denmark)

    Ciobotaru, Mihai; Iov, Florin; Zanchetta, P.;

    2008-01-01

    will be needed in order to control the power flow and to ensure proper and secure operation of this future grid with an increased level of renewable power. These power converters must be able to provide intelligent power management as well as ancillary services. This paper presents an analysis of the natural...... reference frame controller, based on proportional-resonant (PR) technique, for a multi-level H-bridge power converter for Universal and Flexible Power Management in Future Electricity Network. The proposed method is tested in terms of harmonic content in the Point of Common Coupling (PCC), voltage......To pave the way to a sustainable energy future based on a larger share of Distributed Generation (DG), there is a clear need to prepare the European electricity system for the large-scale integration of both renewable and other distributed energy sources. Advanced power electronic converters for DG...

  15. Simulation of the growth of the 3D Rayleigh-Taylor instability in Supernova Remnants using an expanding reference frame

    CERN Document Server

    Fraschetti, Federico; Ballet, Jean; Decourchelle, Anne

    2010-01-01

    Context: The Rayleigh-Taylor instabilities generated by the deceleration of a supernova remnant during the ejecta-dominated phase are known to produce finger-like structures in the matter distribution which modify the geometry of the remnant. The morphology of supernova remnants is also expected to be modified when efficient particle acceleration occurs at their shocks. Aims: The impact of the Rayleigh-Taylor instabilities from the ejecta-dominated to the Sedov-Taylor phase is investigated over one octant of the supernova remnant. We also study the effect of efficient particle acceleration at the forward shock on the growth of the Rayleigh-Taylor instabilities. Methods: We modified the Adaptive Mesh Refinement code RAMSES to study with hydrodynamic numerical simulations the evolution of supernova remnants in the framework of an expanding reference frame. The adiabatic index of a relativistic gas between the forward shock and the contact discontinuity mimics the presence of accelerated particles. Results: The ...

  16. Adaptive rotor current control for wind-turbine driven DFIG using resonant controllers in a rotor rotating reference frame

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This paper proposes an adaptive rotor current controller for doubly-fed induction generator (DFIG), which consists of a proportional (P) controller and two harmonic resonant (R) controllers implemented in the rotor rotating reference frame. The two resonant controllers are tuned at slip frequencies ωslip+ and ωslip-, respectively. As a result, the positive- and negative-sequence components of the rotor current are fully regulated by the PR controller without involving the positive- and negative-sequence decomposition, which in effect improves the fault ride-through (FRT) capability of the DFIG-based wind power generation system during the period of large transient grid voltage unbalance. Correctness of the theoretical analysis and feasibility of the proposed unbalanced control scheme are validated by simulation on a 1.5-MW DFIG wind power generation system.

  17. From Work to Frame in Intermedial References: Joseph Beuys in Three Contemporary German Poems

    Directory of Open Access Journals (Sweden)

    Noël Reumkens

    2009-07-01

    Full Text Available Dans cet article, nous nous interrogeons sur ce qui se produit dans les textes littéraires se référant aux œuvres des arts visuels, qui en premier ressort ne sont pas visuels mais plutôt conceptuels et abstraits. L’œuvre conceptuelle de l’artiste allemand Joseph Beuys (1921-1986 s’appuie sur un cadre conceptuel résumé par le terme de “sculpture sociale”. Notre but est de rechercher comment trois poètes allemands contemporains, Thomas Kling, Durs Grünbein et Ulrike Draesner se rapprochent de cette “sculpture sociale” dans leurs poèmes.This article deals with about what happens in literary texts that refer to visual art works, that in the first place are not visual but rather conceptual and abstract. The conceptual work of the German artist Joseph Beuys (1921-1986 is founded on a conceptual framework that can be summed up under the term “social sculpture”. It is our goal to research exactly how three German contemporary poets, Thomas Kling, Durs Grünbein and Ulrike Draesner approach this “social sculpture” in their poems.En este artículo nos planteamos la cuestión de saber qué sucede con los textos literarios que remiten a obras de artes visuales que en primera instancia no son visuales, sino no más bien conceptuales y abstractos. La obra conceptual del artista alemán José Beuys (1921-1986 se fundamente en un marco conceptual sintetizado con el término de "escultura social ". Nuestro fin es ver cómo tres poetas alemanes contemporáneos, Thomás Kling, Durs Grünbein y Ulrike Draesner, se enfrentan en sus poemas a esta "escultura social".

  18. Temporal frames of reference in three Germanic languages: Individual consistency, interindividual consensus, and cross-linguistic variability.

    Science.gov (United States)

    Rothe-Wulf, Annelie; Beller, Sieghard; Bender, Andrea

    2015-01-01

    A task like "moving a meeting forward" reveals the ambiguity inherent in temporal references. That speakers of U.S. English do not agree on how to solve it is well established: Roughly one half moves the meeting futurewards, the other half pastwards. But the extent to which individual speakers, rather than groups of speakers, consider such phrases as ambiguous has not been scrutinized. Does the split in readings result from a lack of intraindividual consistency or from a lack of interindividual consensus? And how specific is U.S. English in this regard when compared to other closely related Germanic languages? Based on a taxonomy of spatiotemporal frames of reference (FoRs), we conducted two experiments with speakers of Swedish, U.S. English, and German to assess individual preferences for temporal FoRs, intra- and cross-linguistic variability, consistency and long-term stability of these preferences, and possible effects of priming a spatial FoR. The data reveal cross-linguistic differences, both in terms of which temporal FoRs speakers prefer (the absolute FoR in Sweden, the intrinsic FoR in German, and both of these in the US) and in terms of the extent to which these preferences are shared and stable (high consensus and consistency in Sweden and Germany, and low consensus and partial consistency in the US). Overall, no effect of spatial priming was observed; only speakers of U.S. English with a baseline preference for the absolute temporal FoR seemed to be susceptible to spatial priming. Thus, the assumption that temporal references are affected by spatial references is only weakly supported.

  19. 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.

  20. 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;

    2013-01-01

    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 parallel connected three-phase VSIs are derived. The proposed voltage and current inner control loops and the mat......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 parallel connected three-phase VSIs are derived. The proposed voltage and current inner control loops...... and the mathematical models of the VSIs are based on the stationary reference frame. A hierarchical control scheme for the paralleled VSI system is developed comprising two 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 the frequency and amplitude deviations produced by the primary control. Also, a synchronization algorithm is presented in order to connect the MicroGrid to the grid. Experimental results are provided to validate the performance and robustness of the parallel VSI system control...

  1. 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

  2. A Meta-Analytic Path Analysis of the Internal/External Frame of Reference Model of Academic Achievement and Academic Self-Concept

    Science.gov (United States)

    Moller, Jens; Pohlmann, Britta; Koller, Olaf; Marsh, Herb W.

    2009-01-01

    A meta-analysis of 69 data sets ( N = 125,308) was carried out on studies that simultaneously evaluate the effects of math and verbal achievements on math and verbal self-concepts. As predicted by the internal/external frame of reference (I/E) model, math and verbal achievements were highly correlated overall (0.67), but the correlation between…

  3. 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…

  4. 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

  5. 人格测验的参照情境效应%Frame-of-Reference Effect on Personality Tests

    Institute of Scientific and Technical Information of China (English)

    卢谢峰; 唐源鸿; 王孟成

    2012-01-01

    人格测验的参照情境效应是指,在一般人格测验的基础上,设置某种特定的参照情境,进而使测验的效标关联效度得以提高的现象。在过去十余年里,参照情境效应的考察重心从早期的效度证据搜集逐渐转向内部机理的探讨。研究耆试图通过参照情境与效标的逻辑关联、参照情境的被试问变异及被试内变异来解释现象背后的测量学原理。在构念层面则提出“人格和角色认同层级模型”,以此说明参照情境效应的人格机制问题。未来研究可从参照情境的操作范式、参照情境效应的调节机制等方面继续寻求突破。%The Frame-of-Reference (FOR) effect on personality tests refers to a kind of phenomenon that if a specific reference context is set for a plain personality test, the criterion-related validity of this test will be improved. In the past ten years, the focus of the FOR effect studies has gradually shifted from collecting validity evidence to probing its internal mechanism. The psychometric principle of the FOR effect is that various reference inconsistency in subjects' reaction courses, including the between-person variability and the within-person inconsistency of the FOR, will be reduced, when a concordant FOR matching with criterion is provided. It also reflects that the relation between the contextualized personality constructs and the relevent criterion variables is closer to nomological network. According to Wood's Personality and Role Identity Structural Model, the origin of that relation is from the mediating mechanism of "general personality →contextualized personality → role behavior". In practice, personnel assessment experts can use that conclusion, set proper FORs for personality tests, and thus improve the effectiveness of assessment tools. We see three avenues for future studies. First, on the FOR operational paradigm, researchers can incorporate the context priming paradigm into

  6. Celestial Navigation for the Novice

    Science.gov (United States)

    Sadler, Philip M.

    2011-01-01

    What kinds of astronomical lab activities can introductory astronomy students carry out easily in daytime? The most impressive is the determination of their latitude and longitude from observations of the sun. The "shooting of a noon sight” and its "reduction to a position” is a technique still practiced by navigators in this age of GPS. Indeed, the U.S. Coast Guard exams for ocean-going licenses and include celestial navigation. These techniques continue to be used by the military and by private sailors as a backup to electronic navigation systems. We present a method to establish one's latitude and longitude to better than 30 miles from measurements of the sun's altitude that is easily within the capability non-science majors. This is a practical application of astronomy in use the world over. The streamlined method used is based on an easy-to-build protractor and string quadrant. Participants will leave with all materials to conduct this activity in their own classroom.

  7. Verification of the Polish Geodetic Reference Frame by Means of a New Solution Based on Permanent GNSS Data from the Years 2011-2014

    Directory of Open Access Journals (Sweden)

    Liwosz T.

    2016-12-01

    Full Text Available The new solution for the Polish geodetic primary GNSS network was created to verify the currently used reference frame (PL-ETRF2000. The new solution is based on more GNSS data (more daily observation sessions included, a longer data timespan, GLONASS observations added which were processed in a newer reference frame (IGb08 according to up-to-date methodology and using the latest version of Bernese GNSS Software. The new long-term solution (spanning 3.7 years was aligned to the IGb08 reference frame using a minimum constraints approach. We categorized Polish reference stations into two categories according to their data length. We obtained good agreement of the new solution with the PL-ETRF2000: for most stations position differences did not exceed 5 mm in horizontal, and 10 mm in vertical components. However, for 30 stations we observed discontinuities in position time series, mostly due to GNSS equipment changes, which occured after the introduction of PL-ETRF2000. Position changes due to the discontinuities reached 9.1 mm in horizontal components, and 26.9 mm in vertical components. The new solution takes into account position discontinuities, and in addition also includes six new stations which were installed after the introduction of the PL-ETRF2000. Therefore, we propose to update the currently-used reference frame for the Polish geodetic primary network (PL-ETRF2000 with the new solution. The new solution was also accepted by the EUREF Technical Working Group as a class A solution (highest accuracy according to EUREF standards.

  8. Verification of the Polish Geodetic Reference Frame by Means of a New Solution Based on Permanent GNSS Data from the Years 2011-2014

    Science.gov (United States)

    Liwosz, T.; Ryczywolski, M.

    2016-12-01

    The new solution for the Polish geodetic primary GNSS network was created to verify the currently used reference frame (PL-ETRF2000). The new solution is based on more GNSS data (more daily observation sessions included, a longer data timespan, GLONASS observations added) which were processed in a newer reference frame (IGb08) according to up-to-date methodology and using the latest version of Bernese GNSS Software. The new long-term solution (spanning 3.7 years) was aligned to the IGb08 reference frame using a minimum constraints approach. We categorized Polish reference stations into two categories according to their data length. We obtained good agreement of the new solution with the PL-ETRF2000: for most stations position differences did not exceed 5 mm in horizontal, and 10 mm in vertical components. However, for 30 stations we observed discontinuities in position time series, mostly due to GNSS equipment changes, which occured after the introduction of PL-ETRF2000. Position changes due to the discontinuities reached 9.1 mm in horizontal components, and 26.9 mm in vertical components. The new solution takes into account position discontinuities, and in addition also includes six new stations which were installed after the introduction of the PL-ETRF2000. Therefore, we propose to update the currently-used reference frame for the Polish geodetic primary network (PL-ETRF2000) with the new solution. The new solution was also accepted by the EUREF Technical Working Group as a class A solution (highest accuracy) according to EUREF standards.

  9. Orbital motions of astronomical bodies and their centre of mass from different reference frames: a conceptual step between the geocentric and heliocentric models

    Science.gov (United States)

    Guerra, André G. C.; Simeão Carvalho, Paulo

    2016-09-01

    The motion of astronomical bodies and the centre of mass of the system is not always well perceived by students. One of the struggles is the conceptual change of reference frame, which is the same that held back the acceptance of the Heliocentric model over the Geocentric one. To address the question, the notion of centre of mass, motion equations (and their numerical solution for a system of multiple bodies), and change of frame of reference is introduced. The discussion is done based on conceptual and real world examples, using the solar system. Consequently, through the use of simple ‘do it yourself’ methods and basic equations, students can debate complex motions, and have a wider and potentially effective understanding of physics.

  10. Separating Electroweak and Strong interactions in Drell-Yan processes at LHC: leptons angular distributions and reference frames

    CERN Document Server

    Richter-Was, E

    2016-01-01

    Among the physics goals of LHC experiments, precision tests of the Standard Model in the Strong and Electroweak sectors play an important role. Because of nature of the proton-proton processes, observables based on the measurement of the direction and energy of leptons provide the most precise signatures. In the present paper, we concentrate on the angular distribution of Drell-Yan process leptons, in the lepton-pair rest-frame. The vector nature of the intermediate state imposes that distributions are to a good precision described by spherical polynomials of at most second order. We show that with the proper choice of the coordinate frames, only one coefficient in this polynomial decomposition remains sizable, even in the presence of one or two high $p_T$ jets. The necessary stochastic choice of the frames relies on probabilities independent from any coupling constants. This remains true when one or two partons accompany the lepton pairs. In this way electroweak effects can be better separated from strong in...

  11. 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

  12. IN-FLIGHT ALIGNMENT OF INERTIAL NAVIGATION SYSTEM BY CELESTIAL OBSERVATION TECHNIQUE

    Institute of Scientific and Technical Information of China (English)

    ALlJamshaid; FANGJian-cheng

    2005-01-01

    This paper presents an in-flight alignment technique for a strapdown inertial navigation system (SINS) and employs a star pattern recognition procedure for identifying stars sensed by a CCD electrooptical star sensor.Collinearity equations are used to estimate sensor frame star coordinates and the conventional least square differential correction method is used to estimate the unknown orientation angles. A comparison of this attitude with the attitude estimated by the SINS provides axis misalignment angles. Simulations using a Kalman filter are carried out for an SINS and the system employs a local level navigation frame. The space stabilized SINS is discussed in conjunction with the celestial aiding. Based on the observation of the Kalman filter, the estimating and compensating gyro errors, as well as the position and velocity errors caused by the SINS misalignments are calibrated by celestial attitute information.

  13. Construction of mm-level terrestrial reference frame%毫米级地球参考框架的构建

    Institute of Scientific and Technical Information of China (English)

    宋淑丽; 朱文耀; 熊福文; 高峻

    2009-01-01

    It is noted in this paper that the latest international terrestrial reference frame ITRF2005 can't satisfy the current need of monitoring mm-level terrestrial dynamic change.The strategy of using the latest results of ITRF2005,SBL/GGFC(Special Bureau for Loading/Global Geophysical Fluids Center),GRACE and other satellites to construct mm-level terrestrial reference frame is mentioned in the paper.The methods and some preliminary results for two key problems are introduced in this article: non-linear characteristic of crust movement ∑_RΔX_R~I(t) and geocenter motionΔX_0(t) monitored using space technology (GPS,VLBI,SLR and GRACE) and modeled by geophysical factors.The preliminary assessment of accuracy and problems in constructing and realizing mm-level terrestrial reference frame is also introduced in the paper.%本文指出了最新的国际地球参考框架ITRF(International Terrestrial Reference Frame)2005已不能满足当今毫米级地球动态变化监测的需要.提出了利用ITRF2005、SBL/GGFC(Special Bureau for Loading/Global Geophysical Fluids Center)和GRACE(Gravity Recovery and Climate Experiment)等卫星的最新成果,构建毫米级地球参考框架的方案,介绍了对其两个关键问题:地壳非线性运动特征∑_R△X_R~i(t)和地球质心运动△X_0(t)的空间技术(GPS,VLBI,SLR和GRACE)监测和地球物理因素模制的方法和一些初步结果,并对目前建立和实现毫米级地球参考框架存在的问题和所能达到的精度进行了初步评估.

  14. 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.

  15. Relativistic Jets in the Radio Reference Frame Image Database. 1. Apparent Speeds From the First 5 Years of Data

    Science.gov (United States)

    2007-02-11

    simulations by Agudo et al. (2001) suggested that multiple slowly moving conical shocks formed from the interaction of superluminal components with the under...from zero up to this bulk flow speed. A scenario such as this would be consistent with jet simulations such as those of Agudo et al. (2001), in which...Science Award from Research Corporation. REFERENCES Agudo , I., Gomez, J.-L., Martı́, J.-M., Ibáñez, J.-M., Marscher, A. P., Alberdi, A., Aloy, M.-A

  16. Orbital behavior around a nonuniform celestial body

    Science.gov (United States)

    Rosson, Z.; Hall, F.; Vogel, T.

    2016-09-01

    To effectively model the orbit around a nonuniform celestial body, detailed information needs to be determined of the perturbations. This research looked at one of the most crucial perturbations: the nonuniform gravitational field of a celestial body. Given an orbiting particle (a satellite), we utilized numerical methods to calculate its orbit in two dimensions around a discretized center mass structure. The gravitational acceleration imposed on the particle due to each mass point sums vectorally as the particle completes each infinitesimal time step of one orbit. There are noticeable effects on the orbit as the conditions of the center mass change. The development of a simulation code allows for the modelling of the orbit about an irregular body with satisfactory accuracy.

  17. 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.

  18. 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...

  19. An Overview of Major Terrestrial, Celestial, and Temporal Coordinate Systems for Target Tracking

    Science.gov (United States)

    2016-08-10

    quadrant inverse tangent in (B2) is not uniquely defined at the poles (when x “ 0 and y “ 0). However, many implementations of the four-quadrant inverse ...Harmonic Coordinates .................................... 105 APPENDIX E—Principal Axes, Precession, Nutation, and the Pole Tide...on the Celestial Sphere z ` Pole of the Ecliptic ˘ x ˆ IERS Reference Meridian « Dynamical Equinox at Epoch ˙ , P z ` IERS Reference Pole

  20. A New Way of Controlling Parallel-Connected Inverters by Using Synchronous-Reference-Frame Virtual Impedance Loop—Part I: Control Principle

    DEFF Research Database (Denmark)

    Guan, Yajuan; Guerrero, Josep M.; Zhao, Xin

    2016-01-01

    A novel simple and effective autonomous current-sharing controller for parallel three-phase inverters is proposed in this paper. The proposed controller provides faster response and better accuracy in contrast to the conventional droop control, since this novel approach does not require any active...... or reactive power calculations. Instead, a synchronous-reference-frame (SRF) virtual impedance loop and an SRF-based phase-locked loop are used. Stationary analysis is provided in order to identify the inherent mechanism of the direct and quadrature output currents in relation to the voltage amplitude...... from a setup with three parallel 2.2 kW inverters verify the effectiveness of the proposed control strategy in different scenarios....

  1. A stationary reference frame current control for a multi-level H-bridge power converter for universal and flexible power management in future electricity network

    DEFF Research Database (Denmark)

    Ciobotaru, Mihai; Iov, Florin; Zanchetta, Pericle;

    2008-01-01

    for a multi-level cascaded H-bridges power converter used for grid applications. Harmonic content in the Point of Common Coupling, system response for bidirectional power flow, voltage and frequency excursions as well as voltage unbalances and asymmetries and low voltage ride-though capabilities are studied.......More "green" power provided by Distributed Generation will enter into the European electricity network in the near future. In order to control the power flow and to ensure proper and secure operation of this future grid, with an increased level of the renewable power, new power electronic...... converters for grid connection of renewable sources will be needed. These power converters must be able to provide intelligent power management as well as ancillary services. This paper assesses a control method based on the stationary reference frame with Proportional-Resonant current controllers...

  2. Orbital motions of astronomical bodies and their Centre of Mass from different reference frames: a conceptual step between the Geocentric and Heliocentric models

    CERN Document Server

    Guerra, André G C

    2016-01-01

    The motion of astronomical bodies and the centre of mass of the system is not always well perceived by students. One of the struggles is the conceptual change of reference frame, which is the same that held back the acceptance of the Heliocentric model over the Geocentric one. To address the question, the notion of centre of mass, motion equations (and their numerical solution for a system of multiple bodies), and change of referential is introduced. The discussion is done based on conceptual and real world examples, using the solar system. Consequently, through the use of simple "do it yourself" methods and basic equations, students can debate complex motions, and have a wider and potentially effective understanding of physics.

  3. 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.

  4. 基于同步旋转变换及DFT的SVG指令电流检测法%A reference current detection method based on synchronous reference frame transformation and DFT for SVG

    Institute of Scientific and Technical Information of China (English)

    陈丽兵; 史丽萍; 夏正龙; 王攀攀

    2014-01-01

    为使静止无功发生器(Static Var Generator,SVG)具备无功、谐波及不对称电流综合补偿能力,提出了一种基于同步旋转坐标变换及离散傅立叶变换(Discrete Fourier Transform,DFT)的SVG指令电流检测方法。该方法通过在同步旋转坐标系下进行递归离散傅立叶变换,能够实时检测出负载电流中的无功分量、不对称分量以及特征谐波。利用该方法只用一个控制器就能同时对两种特征谐波分量进行补偿,相对于其他方法运算量大大减小,便于工程实现。仿真和实验验证证明了该方法的有效性。%A reference current detection method based on synchronous reference frame transformation and discrete Fourier transform (DFT) is presented to make SVG provide synthetic compensation including reactive power compensation, harmonic compensation and unbalanced current compensation. By using recursive DFT algorithm in the rotating reference frame, the proposed method can be used to extract reactive currents, unbalanced currents and characteristic harmonic currents from the load currents in real time. This method allows the simultaneous compensation of two current harmonics with just one regulator, yielding a significant reduction of the computational effort and easy engineering implementation compared with other methods. The results of simulation and experiment show the validity of this method.

  5. 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

  6. Does the integration of haptic and visual cues reduce the effect of a biased visual reference frame on the subjective head orientation?

    Directory of Open Access Journals (Sweden)

    Marc Gueguen

    Full Text Available BACKGROUND: The selection of appropriate frames of reference (FOR is a key factor in the elaboration of spatial perception and the production of robust interaction with our environment. The extent to which we perceive the head axis orientation (subjective head orientation, SHO with both accuracy and precision likely contributes to the efficiency of these spatial interactions. A first goal of this study was to investigate the relative contribution of both the visual and egocentric FOR (centre-of-mass in the SHO processing. A second goal was to investigate humans' ability to process SHO in various sensory response modalities (visual, haptic and visuo-haptic, and the way they modify the reliance to either the visual or egocentric FORs. A third goal was to question whether subjects combined visual and haptic cues optimally to increase SHO certainty and to decrease the FORs disruption effect. METHODOLOGY/PRINCIPAL FINDINGS: Thirteen subjects were asked to indicate their SHO while the visual and/or egocentric FORs were deviated. Four results emerged from our study. First, visual rod settings to SHO were altered by the tilted visual frame but not by the egocentric FOR alteration, whereas no haptic settings alteration was observed whether due to the egocentric FOR alteration or the tilted visual frame. These results are modulated by individual analysis. Second, visual and egocentric FOR dependency appear to be negatively correlated. Third, the response modality enrichment appears to improve SHO. Fourth, several combination rules of the visuo-haptic cues such as the Maximum Likelihood Estimation (MLE, Winner-Take-All (WTA or Unweighted Mean (UWM rule seem to account for SHO improvements. However, the UWM rule seems to best account for the improvement of visuo-haptic estimates, especially in situations with high FOR incongruence. Finally, the data also indicated that FOR reliance resulted from the application of UWM rule. This was observed more

  7. Compliance Framing - Framing Compliance

    OpenAIRE

    Lutz-Ulrich Haack; Martin C. Reimann

    2012-01-01

    Corporations have to install various organizational measures to comply with legal as well as internal guidelines systematically. Compliance management systems have the challenging task to make use of an internal compliance-marketing approach in order to ensure not only an adequate but also effective compliance-culture. Compliance-literature and findings of persuasive goal-framing-theory give opposite implications for establishing a rather values- versus rule-based compliance-culture respectiv...

  8. Explaining as Mediated Action. An Analysis of Pre-service Teachers' Account of Forces of Inertia in Non-inertial Frames of Reference

    Science.gov (United States)

    de Pereira, Alexsandro Pereira; Lima Junior, Paulo; Rodrigues, Renato Felix

    2016-05-01

    Explaining is one of the most important everyday practices in science education. In this article, we examine how scientific explanations could serve as cultural tools for members of a group of pre-service physics teachers. Specifically, we aim at their use of explanations about forces of inertia in non-inertial frames of reference. A basic assumption of our study is that explanatory tools (e.g., typical explanations learned) shape the ways we think and speak about the world. Drawing on the theory of mediated action, analysis illustrates three major claims on scientific explanations: (1) explaining is an act of actively responding to explanations presented by others (and not only to evidence itself); (2) the actual experience of explaining involves the enactment of power and authority; (3) resistance (not acknowledging an explanation as one's own) might be a constitutive part of learning how to explain (hence, teachers could approach scientific explanation in a less dogmatic way). These assertions expand the possibilities of dialogue between studies of scientific explanations and the social sciences. Implications for science teaching and research in science education are presented.

  9. 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

  10. 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.

  11. 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.

  12. Study on the Notice of Nonconformity Goods under the Draft Common Frame of Reference and Its References to China%欧洲民法典草案交货不符通知制度研究及借鉴

    Institute of Scientific and Technical Information of China (English)

    王金根

    2011-01-01

    不符通知的作用在于给予善意卖方保护,以便于其及时作出应对与补救,同时也便于保存证据。不符通知制度对买卖双方利益影响甚巨。有鉴于此,欧洲民法典草案从不符通知之具体要求到通知例外,都作了详尽规定。与之相比,我国不符通知制度无论是从立法理念还是具体制度上都存在不足,有必要在未来民法典立法中予以修改完善。%The notice of nonconformity aims to protect the bona fide seller so as to facilitate his in-time response and remedies,as well as to preserve evidence.Since this system has great influence on interests of both seller and buyer,the Draft Common Frame of Reference has stipulated in detail specific requirements of notice and notice exceptions.However,there are still imperfections of either legislative conceptions or specific rules as to notice of non-conformity in our Contract Law,therefore it is necessary to modify and improve this system in the future Civil Code of P.R.C.

  13. Framing politics

    OpenAIRE

    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 dissociation of framing from other media effects concepts is not necessarily the ideal way to go in creating a more advanced framing theory. We also provide the first contours of a theory of news framing...

  14. Magnetic-resonance imaging and simplified Kozeny-Carman-model analysis of glass-bead packs as a frame of reference to study permeability of reservoir rocks

    Science.gov (United States)

    Wang, Dayong; Han, Dongyan; Li, Wenqiang; Zheng, Zhanpeng; Song, Yongchen

    2017-03-01

    Permeability variation in reservoir rocks results from the combined effects of various factors, and makes porosity-permeability (ϕ-k) relationships more complex, or, in some cases, non-existent. In this work, the ϕ-k relationship of macroscopically homogeneous glass-bead packs is deduced based on magnetic resonance imaging (MRI) measurement and Kozeny-Carman (K-C) model analysis; these are used as a frame of reference to study permeability of reservoir rocks. The results indicate: (1) most of the commonly used simplified K-C models (e.g. the simplified traditional (omitting specific surface area), high-order, threshold, and fractal models) are suitable for estimating permeability of glass-bead packs. The simplified traditional model does not present obvious dependence on rock samples. Whether for the glass-bead packs or clean natural sandstones, the sample coefficients almost remain invariant. Comparably, the high-order, the fractal, and the threshold models are strongly sample-specific and cannot be extrapolated from the glass-bead packs to natural sandstones; (2) the ϕ-k relationships of quartz sands and silty sandstones resemble those of the glass-bead packs, but they significantly deviate from the K-C models at low porosities due to small pore entry radius; (3) a small amount of intergranular cements (<10%v) does not affect the general variation trend of permeability with porosity but can potentially increase predictive errors of the K-C models, whereas in the case of more cements, the ϕ-k relationships of sandstones become uncertain and cannot be described by any of these K-C models.

  15. Reference frame access under the effects of great earthquakes: a least squares collocation approach for non-secular post-seismic evolution

    Science.gov (United States)

    Gómez, D. D.; Piñón, D. A.; Smalley, R.; Bevis, M.; Cimbaro, S. R.; Lenzano, L. E.; Barón, J.

    2016-03-01

    The 2010, (Mw 8.8) Maule, Chile, earthquake produced large co-seismic displacements and non-secular, post-seismic deformation, within latitudes 28°S-40°S extending from the Pacific to the Atlantic oceans. Although these effects are easily resolvable by fitting geodetic extended trajectory models (ETM) to continuous GPS (CGPS) time series, the co- and post-seismic deformation cannot be determined at locations without CGPS (e.g., on passive geodetic benchmarks). To estimate the trajectories of passive geodetic benchmarks, we used CGPS time series to fit an ETM that includes the secular South American plate motion and plate boundary deformation, the co-seismic discontinuity, and the non-secular, logarithmic post-seismic transient produced by the earthquake in the Posiciones Geodésicas Argentinas 2007 (POSGAR07) reference frame (RF). We then used least squares collocation (LSC) to model both the background secular inter-seismic and the non-secular post-seismic components of the ETM at the locations without CGPS. We tested the LSC modeled trajectories using campaign and CGPS data that was not used to generate the model and found standard deviations (95 % confidence level) for position estimates for the north and east components of 3.8 and 5.5 mm, respectively, indicating that the model predicts the post-seismic deformation field very well. Finally, we added the co-seismic displacement field, estimated using an elastic finite element model. The final, trajectory model allows accessing the POSGAR07 RF using post-Maule earthquake coordinates within 5 cm for ˜ 91 % of the passive test benchmarks.

  16. Identification and Estimation of Postseismic Deformation: Implications for Plate Motion Models, Models of the Earthquake Cycle, and Terrestrial Reference Frame Definition

    Science.gov (United States)

    Kedar, S.; Bock, Y.; Moore, A. W.; Argus, D. F.; Fang, P.; Liu, Z.; Haase, J. S.; Su, L.; Owen, S. E.; Goldberg, D.; Squibb, M. B.; Geng, J.

    2015-12-01

    Postseismic deformation indicates a viscoelastic response of the lithosphere. It is critical, then, to identify and estimate the extent of postseismic deformation in both space and time, not only for its inherent information on crustal rheology and earthquake physics, but also since it must considered for plate motion models that are derived geodetically from the "steady-state" interseismic velocities, models of the earthquake cycle that provide interseismic strain accumulation and earthquake probability forecasts, as well as terrestrial reference frame definition that is the basis for space geodetic positioning. As part of the Solid Earth Science ESDR System) SESES project under a NASA MEaSUREs grant, JPL and SIO estimate combined daily position time series for over 1800 GNSS stations, both globally and at plate boundaries, independently using the GIPSY and GAMIT software packages, but with a consistent set of a prior epoch-date coordinates and metadata. The longest time series began in 1992, and many of them contain postseismic signals. For example, about 90 of the global GNSS stations out of more than 400 that define the ITRF have experienced one or more major earthquakes and 36 have had multiple earthquakes; as expected, most plate boundary stations have as well. We quantify the spatial (distance from rupture) and temporal (decay time) extent of postseismic deformation. We examine parametric models (log, exponential) and a physical model (rate- and state-dependent friction) to fit the time series. Using a PCA analysis, we determine whether or not a particular earthquake can be uniformly fit by a single underlying postseismic process - otherwise we fit individual stations. Then we investigate whether the estimated time series velocities can be directly used as input to plate motion models, rather than arbitrarily removing the apparent postseismic portion of a time series and/or eliminating stations closest to earthquake epicenters.

  17. 固定坐标系下的风力机稳定性分析%STABILITY ANALYSIS OF WIND TURBINE UNDER STATIONARY REFERENCE FRAME

    Institute of Scientific and Technical Information of China (English)

    何玉林; 刘桦; 杜静; 杨显刚

    2011-01-01

    采用仿真软件TurbSim建立紊流风场数据、AeroDyn建立气动力数据、FAST( fatigue,aerodynamics,structures,and turbulence)建立风力发电机组动力学模型,并将三者联合起来,建立完整的风力发电机组系统动力学模型.通过多叶片坐标变换(multi-blade coordinate)将系统动力学模型中与叶片相关的转动自由度转换到固定坐标系中,并进行稳定性分析.以某600 kW失速型风力机为例,根据联合仿真得到该风力机在稳态和紊流风场下的叶尖、塔架的变形和轮毂叶根处的受力,并得到不考虑气动力情况下的风力机系统稳定性结果.%After the stochastic inflow turbulence, the aerodynamcs and the wind turbine's structural dynamic model constructed by simulation softwares of TurbSim, AeroDyn and FAST(fatigue, aerodynamics, structures, and turbulence) respectively, the full dynamic model of wind turbine system has been setup. The DOFs( degree of freedom) related to rotating blades have been transformed into stationary reference frame by using multi-blade coordinate transformation, then stability analysis has been conducted. Hie deformations of blades and tower top have been generated in steady and turbulence wind field for a 600 kW stall-regulated wind turbine and the results of stability analysis at different rotor speed without aerodynamic has been gerenated, and the Coleman diagram ploted according to them.

  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. Modern Celestial Mechanics: From Theory to Applications

    Science.gov (United States)

    Celletti, A.; Ferraz-Mello, S.; Henrard, J.

    2002-10-01

    This book is intended to diffuse original research results interesting to people working in Celestial Mechanics in both theory and applications. Theoretical investigators will find several results on Hamiltonian Dynamics, Periodic Orbits, Chaos Diagnostic and Perturbations Theory. Applications cover several directions of research starting with those related to space exploration (mission design and space research) to those related to astronomy (extrasolar planets, asteroids, Near Earth asteroids). Since this book carries original results, it is unique and complements similar books and journals. Some of the subjects have great media appeal: the risk of impact of space debris on the Space Station, the possibility of fly-by missions to asteroids approaching dangerously to our planet, the study of the orbits of these objects, etc. Appealing for a large audience among scientists are the subjects related to Chaos and Order as well as those centered on the study of the dynamics of exoplanets (extrasolar planets). The appeal of the more theoretical papers lies in the fact that they make a tour on the state-of-the-art of several classical problems. Link: http://www.wkap.nl/prod/b/1-4020-0762-0

  20. Magnetic information calibrates celestial cues during migration.

    Science.gov (United States)

    Sandberg; Bäckman; Moore; Lõhmus

    2000-10-01

    Migratory birds use celestial and geomagnetic directional information to orient on their way between breeding and wintering areas. Cue-conflict experiments involving these two orientation cue systems have shown that directional information can be transferred from one system to the other by calibration. We designed experiments with four species of North American songbirds to: (1) examine whether these species calibrate orientation information from one system to the other; and (2) determine whether there are species-specific differences in calibration. Migratory orientation was recorded with two different techniques, cage tests and free-flight release tests, during autumn migration. Cage tests at dusk in the local geomagnetic field revealed species-specific differences: red-eyed vireo, Vireo olivaceus, and northern waterthrush, Seiurus noveboracensis, selected seasonally appropriate southerly directions whereas indigo bunting, Passerina cyanea, and grey catbird, Dumetella carolinensis, oriented towards the sunset direction. When tested in deflected magnetic fields, vireos and waterthrushes responded by shifting their orientation according to the deflection of the magnetic field, but buntings and catbirds failed to show any response to the treatment. In release tests, all four species showed that they had recalibrated their star compass on the basis of the magnetic field they had just experienced in the cage tests. Since release tests were done in the local geomagnetic field it seems clear that once the migratory direction is determined, most likely during the twilight period, the birds use their recalibrated star compass for orientation at departure. Copyright 2000 The Association for the Study of Animal Behaviour.

  1. 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...

  2. The stratification of regolith on celestial objects

    CERN Document Server

    Schräpler, Rainer; von Borstel, Ingo; Güttler, Carsten

    2015-01-01

    All atmosphere-less planetary bodies are covered with a dust layer, the so-called regolith, which determines the optical, mechanical and thermal properties of their surface. These properties depend on the regolith material, the size distribution of the particles it consists of, and the porosity to which these particles are packed. We performed experiments in parabolic flights to determine the gravity dependency of the packing density of regolith for solid-particle sizes of 60 $\\mu$m and 1 mm as well as for 100-250 $\\mu$m-sized agglomerates of 1.5 $\\mu$m-sized solid grains. We utilized g-levels between 0.7 m s$^{-2}$ and 18 m s$^{-2}$ and completed our measurements with experiments under normal gravity conditions. Based on previous experimental and theoretical literature and supported by our new experiments, we developed an analytical model to calculate the regolith stratification of celestial rocky and icy bodies and estimated the mechanical yields of the regolith under the weight of an astronaut and a spacec...

  3. 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.

  4. Industrial Scale Production of Celestial Body Simulants Project

    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...

  5. A Review of Celestial Burying Ground in Tibet

    Institute of Scientific and Technical Information of China (English)

    YUQIAN

    2005-01-01

    Celestial burying ground ,also called “Mandala”,is where life leaves and comes.A huge piece of stone hidden in high mountains is surrounded by burning plants that give up smoke going up into the air.

  6. BIPM/IAU Joint Committee on relativity for space-time reference systems and metrology

    Science.gov (United States)

    Petit, G.

    At the Kyoto General Assembly, the IAU endorsed, by its Resolution B3 (1997), the creation of the Joint Committee on Relativity for space-time reference systems and metrology (JCR), which was also approved by the Comité International des Poids et Mesures (CIPM) at its 86th meeting in September 1997. Its tasks are ``to establish definitions and conventions to provide a coherent relativistic frame ....... and to develop the adopted definitions and conventions for practical application by the user." The web site of the JCR (www.bipm.fr/WG/CCTF/JCR) contains the headlines of the JCR work. The BIPM/IAU JCR has worked in collaboration with the IAU Working Group on relativity for celestial mechanics and astrometry (RCMA) on the problems of astronomical relativistic space-time reference frames. A document was established in common (document jcrissue.html on the JCR web site) discussing as much as possible all topics that may be addressed by the two groups. The RCMA has specified a consistent framework for defining the barycentric and geocentric celestial reference systems at the first post-Newtonian level. Because new clock technology and space missions will necessitate the application of this framework for time and frequency measurements in the solar system, the JCR focused on these applications. The paper outlines the conclusions of the work and the proposed IAU resolutions, that were discussed at IAU Colloquium 180 in March 2000.

  7. 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).

  8. The program of CNC machine not following Descartes reference frame%不遵循笛卡尔坐标系的数控机床加工程序编制

    Institute of Scientific and Technical Information of China (English)

    耿欣; 顾红光

    2013-01-01

    针对不遵循笛卡尔坐标系的专用数控机床不能按通用的数控指令进行编程的问题,运用宏程序编制一螺旋插补铣的加工程序.%Aiming at the CNC machine can't program with standard dictate not following Descartes reference frame, here program a screw interpolation milling programm with Macro program.

  9. 基于双dq坐标变换的三相电压锁相环的研究%Study of three-phase voltage phase locked loop based on double dq transformation synchronous reference frame

    Institute of Scientific and Technical Information of China (English)

    辛业春; 李国庆; 王尧; 王振浩

    2014-01-01

    This paper proposes a kind of method of three-phase voltage phase locked loop under three-phase unbalanced voltage. When the positive dq synchronous reference frame transforms, the dq axis voltage component will contain AC component caused by negative sequence voltage component which leads to the error of the three-phase voltage phase locked loop (PLL) based on the dq synchronous reference frame transformation. After the dq axis DC voltage component extracted from negative sequence dq synchronous reference frame transformation compensates positive sequence dq transformation synchronous reference frame q axis voltage component, the positive sequence voltage phase can be locked accurately and quickly. By the way of the negative sequence dq synchronous reference frame d axis and q axis DC voltage component detecting negative sequence voltage initial phase angle, the negative sequence voltage phase can be locked. The simulation results show that, this method can achieve the purpose that three-phase power supply frequency, positive sequence voltage phase and the negative sequence voltage phase can be fast and accurately locked in case of unbalanced three-phase voltage.%提出了一种三相电压不平衡情况下,三相电压基波频率、正序电压分量和负序电压分量相位锁定方法。正序dq坐标变换时,负序电压分量将在dq轴电压分量上产生交流分量,导致基于dq坐标变换的三相电压锁相环存在误差;通过提取负序dq坐标变换中dq轴的直流电压分量,对正序dq坐标变换q轴电压分量进行补偿,从而准确快速锁定正序基波电压相位。通过负序dq坐标中d轴和q轴的直流电压分量检测负序电压初相角,锁定负序电压相位。仿真结果表明,该方法能够快速准确地锁定三相电源在不对称情况下的基波频率、正序电压相位和负序电压相位。

  10. 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

  11. Self-face Advantage Benefits from a Visual Self-reference Frame%自我参照框架决定了自我面孔优势效应的出现

    Institute of Scientific and Technical Information of China (English)

    王凌云; 张明; 隋洁

    2011-01-01

    研究使用外显面孔再认实验(实验一)和内隐面孔感知实验(实验二)检验自我参照框架是否是自我面孔加工优势出现的决定性因素这一假设.具有不同朝向(左或右)的被试自己面孔和朋友面孔呈现在视野中央,实验一中,被试的任务为参照自我框架(观察者角度)或他人框架(被观察的像的角度)判断自我面孔的朝向(忽视朋友面孔),或者判断朋友面孔的朝向(忽视自我面孔);实验二中,被试的任务为参照自我框架或他人框架判断所有面孔的朝向.结果表明:自我参照框架促进自我面孔加工优势的出现,而他人参照框架消减自我面孔优势,这种效应稳定地存在于外显和内隐两项任务中.并且,自我参照框架对自我优势效应的促进作用不依赖于面孔刺激背景.%One responds faster to own faces than the faces of others. Although this self-advantage effect in face processing has been well documented, the mechanism underlying the phenomena is far from clear. A plausible account of the effect is that self-face as the salient stimulus automatically attracts one's attention relative to others' faces. An alternative interpretation based on the theory of social cognition stresses the implicit positive association between the self and positive trait adjectives, suggesting that such implicit associations may contribute to the self-advantage. Here we propose that the self-reference frame (making judgments from first-person perspective) facilitates the self-face processing compared to the processing of others' faces.We reported two experiments to assess the role of the self-reference frame in the self-advantage effect by manipulating the judgment-reference frame (self- vs. other-reference) and the attentional level (explicit vs.implicit task). There were sixteen pairs of gender matched participants in Experiment 1, they selectively judged the orientation of self Of familiar faces while ignoring the familiar or

  12. 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 dissoc

  13. Framing theory

    NARCIS (Netherlands)

    de Vreese, C.H.; Lecheler, S.; Mazzoleni, G.; Barnhurst, K.G.; Ikeda, K.; Maia, R.C.M.; Wessler, H.

    2016-01-01

    Political issues can be viewed from different perspectives and they can be defined differently in the news media by emphasizing some aspects and leaving others aside. This is at the core of news framing theory. Framing originates within sociology and psychology and has become one of the most used th

  14. Dynamical Configurations of Celestial Systems Comprised of Multiple Irregular Bodies

    CERN Document Server

    Jiang, Yu; Baoyin, Hexi; Li, Junfeng

    2016-01-01

    This manuscript considers the main features of the nonlinear dynamics of multiple irregular celestial body systems. The gravitational potential, static electric potential, and magnetic potential are considered. Based on the three established potentials, we show that three conservative values exist for this system, including a Jacobi integral. The equilibrium conditions for the system are derived and their stability analyzed. The equilibrium conditions of a celestial system comprised of n irregular bodies are reduced to 12n minus 9 equations. The dynamical results are applied to simulate the motion of multiple-asteroid systems. The simulation is useful for the study of the stability of multiple irregular celestial body systems and for the design of spacecraft orbits to triple asteroid systems discovered in the solar system. The dynamical configurations of the five triple-asteroid systems 45 Eugenia, 87 Sylvia, 93 Minerva, 216 Kleopatra, and 136617 1994CC, and the six-body system 134340 Pluto are calculated and...

  15. Fusion Frames and -Frames in Banach Spaces

    Indian Academy of Sciences (India)

    Amir Khosravi; Behrooz Khosravi

    2011-05-01

    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 show that -frames, fusion frames and Banach -frames are stable under small perturbations and invertible operators.

  16. Interaction between spatial domain and spatial reference frame in deaf and hearing populations%听障和听力正常人群空间主导性和空间参照框架的交互作用

    Institute of Scientific and Technical Information of China (English)

    王爱君; 沈路; 迟莹莹; 刘晓乐; 陈骐; 张明

    2016-01-01

    Spatial location of an object can be represented in the human brain based on allocentric and egocentric reference frames. The perception/action hypothesis of the ventral and dorsal visual streams proposed that egocentric representations are readily encoded in the dorsal stream as sensorimotor representations, and allocentric representations are encoded in the ventral stream as perceptual representations. In addition, the dorsal visual stream, which transforms visual information into sensorimotor representations is implicated in near-space processing, and the ventral stream, which transforms visual information into perceptual representations is involved in the conscious perception of objects in far space. It has been well documented that how the spatial domain and spatial reference frame works, separately. However, it remains poorly understood how the spatial domain interacts with spatial reference frame, especially for the deaf populations. In present study, we synchronously operated different spatial domains (near vs. far) and different spatial reference frames (egocentric vs. allocentric) to investigate the potential interactions in deaf and hearing populations. By asking 17 congenitally deaf participants and 17 hearing participants to perform allocentric and egocentric judgment tasks on the same stimulus set in near and far spaces, respectively, forming a 2 by 2 factorial design in Experiment 1. The stimuli in each trial contained two 3-D objects: a fork on the top of a round orange plate. In near space, stimuli were presented on a screen with the eye-to-screen distance as 50 cm, and in far space, stimuli were presented via a projector on a screen with the eye-to-screen distance as 226 cm. Retinotopic sizes of the objects and visual angles of the egocentric and allocentric distances were both matched for near and far spaces. To test the sense of balance was impaired in the deaf group of the present experiment, we asked both groups to perform a open loop pointing

  17. Introduction on background medium theory about celestial body motion orbit and foundation of fractional-dimension calculus about self-similar fractal measure calculation

    Science.gov (United States)

    Yan, Kun

    2007-04-01

    In this paper, by discussing the basic hypotheses about the continuous orbit and discrete orbit in two research directions of the background medium theory for celestial body motion, the concrete equation forms and their summary of the theoretic frame of celestial body motion are introduced. Future more, by discussing the general form of Binet's equation of celestial body motion orbit and it's solution of the advance of the perihelion of planets, the relations and differences between the continuous orbit theory and Newton's gravitation theory and Einstein's general relativity are given. And by discussing the fractional-dimension expanded equation for the celestial body motion orbits, the concrete equations and the prophesy data of discrete orbit or stable orbits of celestial bodies which included the planets in the Solar system, satellites in the Uranian system, satellites in the Earth system and satellites obtaining the Moon obtaining from discrete orbit theory are given too. Especially, as the preliminary exploration and inference to the gravitation curve of celestial bodies in broadly range, the concept for the ideal black hole with trend to infinite in mass density difficult to be formed by gravitation only is explored. By discussing the position hypothesis of fractional-dimension derivative about general function and the formula form the hypothesis of fractional-dimension derivative about power function, the concrete equation formulas of fractional-dimension derivative, differential and integral are described distinctly further, and the difference between the fractional-dimension derivative and the fractional-order derivative are given too. Subsequently, the concrete forms of measure calculation equations of self-similar fractal obtaining by based on the definition of form in fractional-dimension calculus about general fractal measure are discussed again, and the differences with Hausdorff measure method or the covering method at present are given. By applying

  18. Expansion of Frames to Tight Frames

    Institute of Scientific and Technical Information of China (English)

    Deng Feng LI; Wen Chang SUN

    2009-01-01

    We show that every Bessel sequence (and therefore every frame) in a separable Hilbert space can be expanded to a tight frame by adding some elements. The proof is based on a recent generalization of the frame concept, the g-frame, which illustrates that g-frames could be useful in the study of frame theory. As an application, we prove that any Gabor frame can be expanded to a tight frame by adding one window function.

  19. Schroedinger Equation and the Quantization of Celestial Systems

    Directory of Open Access Journals (Sweden)

    Smarandache F.

    2006-04-01

    Full Text Available In the present article, we argue that it is possible to generalize Schroedinger equation to describe quantization of celestial systems. While this hypothesis has been described by some authors, including Nottale, here we argue that such a macroquantization was formed by topological superfluid vortice. We also provide derivation of Schroedinger equation from Gross-Pitaevskii-Ginzburg equation, which supports this superfluid dynamics interpretation.

  20. 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

  1. A Celestial Assisted INS Initialization Method for Lunar Explorers

    Directory of Open Access Journals (Sweden)

    Jiancheng Fang

    2011-07-01

    Full Text Available The second and third phases of the Chinese Lunar Exploration Program (CLEP are planning to achieve Moon landing, surface exploration and automated sample return. In these missions, the inertial navigation system (INS and celestial navigation system (CNS are two indispensable autonomous navigation systems which can compensate for limitations in the ground based navigation system. The accurate initialization of the INS and the precise calibration of the CNS are needed in order to achieve high navigation accuracy. Neither the INS nor the CNS can solve the above problems using the ground controllers or by themselves on the lunar surface. However, since they are complementary to each other, these problems can be solved by combining them together. A new celestial assisted INS initialization method is presented, in which the initial position and attitude of the explorer as well as the inertial sensors’ biases are estimated by aiding the INS with celestial measurements. Furthermore, the systematic error of the CNS is also corrected by the help of INS measurements. Simulations show that the maximum error in position is 300 m and in attitude 40″, which demonstrates this method is a promising and attractive scheme for explorers on the lunar surface.

  2. Framing scales and scaling frames

    NARCIS (Netherlands)

    Lieshout, van M.; Dewulf, A.; Aarts, M.N.C.; Termeer, C.J.A.M.

    2009-01-01

    Policy problems are not just out there. Actors highlight different aspects of a situation as problematic and situate the problem on different scales. In this study we will analyse the way actors apply scales in their talk (or texts) to frame the complex decision-making process of the establishment o

  3. The IAA Cosmic Study 'Protecting the Environment of Celestial Bodies'

    Science.gov (United States)

    Rettberg, Petra; Hofmann, Mahulena; Williamson, Mark

    The study group tasked with producing this International Academy of Astronautics (IAA) `Cosmic Study' on Protecting the Environment of Celestial Bodies was formed under the aus-pices of IAA Commission V (Space Policy, Law Economy). The members of the international, multidisciplinary team assembled to undertake the Study accept, as a premise, the Planetary Protection Policy guidelines developed by COSPAR, which differentiate the degree of protec-tion according to the type of space activity and the celestial body under investigation (such that fly-by missions have less stringent requirements than lander missions, while Mars is `better protected' than the Moon). However, this Study goes deliberately beyond the interpretation of `Planetary Protection' as a set of methods for protecting the planets from biological con-tamination and extends consideration to the geophysical, industrial and cultural realms. The Study concludes that, from the perspective of current and future activities in outer space, present measures aimed at protecting the space environment are insufficient. Deficiencies in-clude a lack of suitable in-situ methods of chemical and biological detection and the absence of a systematic record of radioactive contaminants. Other issues identified by the Study include an insufficient legal framework, a shortage of effective economic tools and a lack of political will to address these concerns. It is expected that new detection methods under development, and the resultant increase in microbiological knowledge of the planetary surfaces, will lead to changes in the COSPAR planetary protection guidelines and bioburden limits. It is important, however, that any new approaches should not hamper future exploration and exploitation of celestial bodies more than absolutely necessary. The Study addresses the need to find a balance between protection and freedom of action. From a legal perspective, the Study concludes that a general consensus on protection of the

  4. 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.

  5. Mixed quantum/classical theory for inelastic scattering of asymmetric-top-rotor + atom in the body-fixed reference frame and application to the H{sub 2}O + He system

    Energy Technology Data Exchange (ETDEWEB)

    Semenov, Alexander [Chemistry Department, Wehr Chemistry Building, Marquette University, Milwaukee, Wisconsin 53201-1881 (United States); PSL Research University, Observatoire de Paris, Sorbonne Universités, UPMC Univ Paris 06, ENS, UCP, CNRS, UMR8112, LERMA, 5 Place Janssen, 92195 Meudon (France); Dubernet, Marie-Lise [PSL Research University, Observatoire de Paris, Sorbonne Universités, UPMC Univ Paris 06, ENS, UCP, CNRS, UMR8112, LERMA, 5 Place Janssen, 92195 Meudon (France); Babikov, Dmitri, E-mail: dmitri.babikov@mu.edu [Chemistry Department, Wehr Chemistry Building, Marquette University, Milwaukee, Wisconsin 53201-1881 (United States)

    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 H{sub 2}O + He. We found that MQCT is somewhat less accurate at lower scattering energies. For example, below E = 1000 cm{sup −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{sup −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{sup 2}, where n is the number of channels. This is more favorable than the full-quantum inelastic scattering calculations that scale as n{sup 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.

  6. 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.

  7. TRIP: General computer algebra system for celestial mechanics

    Science.gov (United States)

    Laskar, J.; Gastineau, M.

    2012-10-01

    TRIP is an interactive computer algebra system that is devoted to perturbation series computations, and specially adapted to celestial mechanics. Its development started in 1988, as an upgrade of the special purpose FORTRAN routines elaborated by J. Laskar for the demonstration of the chaotic behavior of the Solar System. TRIP is a mature and efficient tool for handling multivariate generalized power series, and embeds two kernels, a symbolic and a numerical kernel. This numerical kernel communicates with Gnuplot or Grace to plot the graphics and allows one to plot the numerical evaluation of symbolic objects.

  8. 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.

  9. 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 th....../NY: Continuum. Hallahan, Kirk. 1999. Seven models of framing: Implications for public relations. Journal of Public Relations Research, 11(3): 205-242....... 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...... considerable strain on the Bank and its image, leading it to reconsider its previous strategy of denial of responsibility. References Entman, Robert M. 1993. Framing: Toward clarification of a fractured paradigm. Journal of Communication, 41: 6-25. Gunnarsson, Britt-Louise. 2009. Professional Discourse. London...

  10. 谐波畸变电网下的单相同步旋转坐标系锁相环%Single-phase Synchronous Reference Frame Phase-locked Loop Under Harmonic Distorted Power Grid Condition

    Institute of Scientific and Technical Information of China (English)

    刘华吾; 孙永恒; 胡海兵; 邢岩

    2016-01-01

    锁相环技术是并网变流器的核心技术之一。针对传统单相同步旋转坐标系锁相环在畸变电网下锁相精度差的问题,提出一种基于离散傅里叶变换(DFT )的高精度锁相环技术。基于DFT的锁相技术的核心问题是如何准确获取电网频率,将DFT 和单相同步旋转坐标系锁相环相结合,利用DFT 的优异选择性滤波性能和相角变换性质,从畸变电网信号中准确提取基波和生成虚拟正交信号,在同步旋转坐标系提取电网频率,实现DFT 的频率自适应,最终无静差、高精度跟踪电网相位。仿真和实验结果表明,所提出的锁相环对电网电压的畸变谐波、直流偏置误差和电网频率脉动等有很好的适应性,在各种电网条件下,均能准确地跟踪电网电压相位,验证了该锁相方法的有效性和优越性。%The phase‐locked loop ( PLL) is a key aspect of grid‐tied converters . A new PLL technique based on discrete Fourier transform (DFT) is proposed to improve the performances of conventional synchronous reference frame PLLs under distorted power grid conditions . The major challenge of the category of DFT based synchronization methods is how to accurately obtain the grid frequency . For this problem , this paper combines the DFT with the single‐phase synchronous reference frame PLL . It utilizes the selective filtering and phase shifting properties of DFT to accurately extract the fundamental and generate its virtual orthogonal signals from the distorted grid . Then by transforming to the synchronous reference frame and properly control the q‐component , accurate synchronization with zero steady state errors is achieved . Besides , grid frequency variations are incorporated by adjusting the sampling period of DFT according to the estimated frequency . Simulation and experimental results show that the proposed DFT‐based PLL offers high harmonics immunity and DC component rejection

  11. THE EVOLUTION OF PERCEPTUAL FRAMES OF REFERENCE.

    Science.gov (United States)

    the Estimation of Number, by William Bevan and Edward D. Turner. Technical rept. no. 13; The Influence of ...Lightness upon the Judgment of Size: An Exercise in Multi-Dimensional Psychophysics, by William Bevan and Edward D. Turner. Technical rept. no. 14...Current Trends and Issues in Adaptation-Level theory, by Harry Helson. Technical rept. no. 15; and Reaction time as a function of the Temporal Pattern of Stimulation, by William Bevan and Donald Hardesty. Technical rept. no.

  12. 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...

  13. Rigid Quasilocal Frames

    CERN Document Server

    McGrath, Paul L

    2014-01-01

    In this thesis, I examine in detail the properties of rigid quasilocal frames (RQF), which have been proposed as a geometrically natural way to define spatially extended reference frames in general relativity. I also explore their usefulness, in particular, as a tool for constructing completely general conservation laws that do not rely on the presence of spacetime symmetries and include both matter and gravitational contributions without the need for any ad hoc structures such as pseudotensors. In doing so, I show how the RQF approach affords a deeper understanding of the nature of gravitational fluxes via the equivalence principle. Finally, I apply the RQF formalism to explore Ehrenfest's rotating disk paradox, a generalization of Archimedes' law to curved spacetime, tidal interactions for Earth's and Jupiter's moons, and more.

  14. [The framing effect: medical implications].

    Science.gov (United States)

    Mazzocco, Ketti; Cherubini, Paolo; Rumiati, Rino

    2005-01-01

    Over the last 20 years, many studies explored how the way information is presented modifies choices. This sort of effect, referred to as "framing effects", typically consists of the inversion of choices when presenting structurally identical decision problems in different ways. It is a common assumption that physicians are unaffected (or less affected) by the surface description of a decision problem, because they are formally trained in medical decision making. However, several studies showed that framing effects occur even in the medical field. The complexity and variability of these effects are remarkable, making it necessary to distinguish among different framing effects, depending on whether the effect is obtained by modifying adjectives (attribute framing), goals of a behavior (goal framing), or the probability of an outcome (risky choice framing). A further reason for the high variability of the framing effects seems to be the domain of the decision problem, with different effects occurring in prevention decisions, disease-detection decisions, and treatment decisions. The present work reviews the studies on framing effects, in order to summarize them and clarify their possible role in medical decision making.

  15. On the abundance of deuterium in celestial objects

    Science.gov (United States)

    Lundin, Rickard; Kero, Johan; Liszka, Ludwik

    2016-04-01

    The deuterium hydrogen ratio (D/H) is the subject of conflicting ideas about the origin of water on the Earth. The present D/H ratio in the Earth oceans (≈1.5x10-4) is substantially lower than most, if not all potential cosmic sources. Furthermore, other celestial bodies, including interstellar space, display a fairly wide range of D/H ratios superseding the terrestrial one. Escape processes may in part explain higher D/H ratios on Mars and Venus, but cannot explain the Earth's low ratio compared to that of the potential sources (e.g. comets and meteors), unless a deuterium "removal" process can be inferred that reduces the D/H ratio. Alternatively, the D/H ratio in the Earth's ocean represents a time capsule of a yet to be identified cosmic source. It is here hypothesized that the former is the cause, a "removal" of deuterium in matter (carbohydrates, water etc.) having high (pristine) D/H ratios. By "removal" is here meant an isotope transmutation, i.e. deuterium is transmuted to hydrogen plus a thermal neutron, a process requiring >2.25 MeV (≈3.6·10-13 J). However, once released a thermal neutron will eventually fuse with another heavier element by thermal neutron capture, a process that may lead to energy in excess of the spallation energy. The energy gain differs for different isotopes, but if exceeding unity it will induce more heat/power than the input power, maintaining power production over time. A gain less than unity will still result in deuterium removal, but also isotope transmutation, and/or element transmutation via β± decay. This report gives a theoretical background for the plasma forcing that can lead to thermal neutron spallation, a process that changes/decrease the D/H ratio in celestial objects. The applicability of the theory will be tested on celestial objects subjected to strong dynamic, and electromagnetic forcing, by the Sun or during the entry of high-speed objects into the Earth's atmosphere.

  16. 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.

  17. 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.

  18. Incontri celesti, vita del padre Clavio in cinque atti

    CERN Document Server

    Sigismondi, Costantino

    2011-01-01

    The year 2012 will be the fourth centennial year of the Jesuit Christopher Clavius (1535-1612), known as the Euclid of XVI century and the collaborator of the Pope Gregory XIII for the calendar reformation. In the occasion of the year of astronomy I wrote a short theatre pi\\`ece "Celestial encounters" dedicated to the life of Ft. Clavius. He observed two total eclipses from centreline in 1560 in Coimbra and in 1567 in Rome, a fact which is remarkable even for contemporary astronomers. The story is developed around those trips: scientific and religious motivations are put in evidence with historical and fantasy, but realistic, facts. An interregional project between Switzerland and Italy, dedicated to the development of high resolution CMOS camera for astronomy and medical sciences has been entitled to Clavius and will produce high resolution measurements of solar diameter.

  19. An approach to Mel'nikov theory in celestial mechanics

    CERN Document Server

    Cicogna, G

    1999-01-01

    Using a completely analytic procedure - based on a suitable extension of a classical method - we discuss an approach to the Poincaré-Mel'nikov theory, which can be conveniently applied also to the case of non-hyperbolic critical points, and even if the critical point is located at the infinity. In this paper, we concentrate our attention on the latter case, and precisely on problems described by Kepler-like potentials in one or two degrees of freedom, in the presence of general time-dependent perturbations. We show that the appearance of chaos (possibly including Arnol'd diffusion) can be proved quite easily and in a direct way, without resorting to singular coordinate transformations, such as the McGehee or blowing-up transformations. Natural examples are provided by the classical Gyldén problem, originally proposed in celestial mechanics, but also of interest in different fields, and by the general 3-body problem in classical mechanics.

  20. 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.

  1. 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

  2. Parameter Design of Single Synchronous Reference Frame Software Phase Locked Loop%单同步坐标系软件锁相环控制器参数设计

    Institute of Scientific and Technical Information of China (English)

    夏泽中; 冯林; 王友阳; 黄刚

    2015-01-01

    Phase-locked loop ( PLL) is essential for detecting the grid phase angle in grid converters , its speed and accura-cy directly affects the performance of synchronous control system relying on PLLs .Some basic principles of the single synchronous reference frame phase-locked loop ( PLL) were firstly presented and analyzed .Partial differential is employed for analyzing the control scheme of the proposed PLL .As the transfer function of controller is a typical II system , parameter was designed in a typ-ical method and its digital implementation was discussed .The performance of the proposed designing method was verified by ex-periments .%针对复杂的锁相环控制器参数设计问题,提出了一种简单实用的控制器参数设计方法。在分析三相锁相环原理的基础上,对单同步坐标系软件锁相环控制结构进行微偏线性化处理,求出其控制器等效传递函数为典型II型系统,按照典型II型系统参数设计原则推导出连续系统下的PI参数设计公式。通过对连续系统控制器离散化处理,推导出一套简单实用的数字系统三相软件锁相环控制器参数设计公式。建模仿真结果表明,锁相环系统动静态性能优越,验证了由该公式设计PI参数的合理性与实用性。

  3. The Heroic Framing of US Foreign Policy

    OpenAIRE

    2010-01-01

    This dissertation concerns the US presidential use of heroic framing in connection with foreign policy. I identify "heroic framing" as speech which describes policies in terms evoking the heroic narrative, either explicitly or implicitly through references to heroic characters. The technique of heroic framing both encourages audiences to view a situation in terms of stark moral absolutes and normalizes casualties and violence as an aspect of these heroic conflicts. This rhetorical technique t...

  4. An analytical model for the celestial distribution of polarized light, accounting for polarization singularities, wavelength and atmospheric turbidity

    Science.gov (United States)

    Wang, Xin; Gao, Jun; Fan, Zhiguo; Roberts, Nicholas W.

    2016-06-01

    We present a computationally inexpensive analytical model for simulating celestial polarization patterns in variable conditions. We combine both the singularity theory of Berry et al (2004 New J. Phys. 6 162) and the intensity model of Perez et al (1993 Sol. Energy 50 235-245) such that our single model describes three key sets of data: (1) the overhead distribution of the degree of polarization as well as the existence of neutral points in the sky; (2) the change in sky polarization as a function of the turbidity of the atmosphere; and (3) sky polarization patterns as a function of wavelength, calculated in this work from the ultra-violet to the near infra-red. To verify the performance of our model we generate accurate reference data using a numerical radiative transfer model and statistical comparisons between these two methods demonstrate no significant difference in almost all situations. The development of our analytical model provides a novel method for efficiently calculating the overhead skylight polarization pattern. This provides a new tool of particular relevance for our understanding of animals that use the celestial polarization pattern as a source of visual information.

  5. 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.

  6. The periodic dynamics of the irregular heterogeneous celestial bodies

    Science.gov (United States)

    Lan, Lei; Yang, Mo; Baoyin, Hexi; Li, Junfeng

    2017-02-01

    In this paper, we develop a methodology to study the periodic dynamics of irregular heterogeneous celestial bodies. Heterogeneous bodies are not scarce in space. It has been found that bodies, such as 4 Vesta, 624 Hektor, 87 Sylvia, 16 Psyche and 25143 Itokawa, may all have varied internal structures. They can be divided into large-scale and small-scale cases. The varied internal structures of large-scale bodies always result from gradient pressure inside, which leads to compactness differences of the inner material. However, the heterogeneity of a small-scale body is always reflected by the different densities of different areas, which may originate from collision formation from multiple objects. We propose a modeling procedure for the heterogeneous bodies derived from the conventional polyhedral method and then compare its dynamical characteristics with those of the homogeneous case. It is found that zero-velocity curves, positions of equilibrium points, types of bifurcations in the continuation of the orbital family and the stabilities of periodic orbits near the heterogeneous body are different from those in the homogeneous case. The suborbicular orbits near the equatorial plane are potential parking orbits for a future mission, so we discuss the switching of the orbital stability of the family because it has fundamental significance to orbit maintenance and operations around actual asteroids.

  7. Advanced Spacecraft Navigation and Timing Using Celestial Gamma-Ray Sources Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed novel program will use measurements of the high-energy photon output from gamma-ray celestial sources to design a new, unique navigation system. This...

  8. Prime tight frames

    DEFF Research Database (Denmark)

    Lemvig, Jakob; Miller, Christopher; Okoudjou, Kasso A.

    2014-01-01

    to suggest effective analysis and synthesis computation strategies for such frames. Finally, we describe all prime frames constructed from the spectral tetris method, and, as a byproduct, we obtain a characterization of when the spectral tetris construction works for redundancies below two.......We introduce a class of finite tight frames called prime tight frames and prove some of their elementary properties. In particular, we show that any finite tight frame can be written as a union of prime tight frames. We then characterize all prime harmonic tight frames and use thischaracterization...

  9. Optimally Sparse Frames

    CERN Document Server

    Casazza, Peter G; Krahmer, Felix; Kutyniok, Gitta

    2010-01-01

    Frames have established themselves as a means to derive redundant, yet stable decompositions of a signal for analysis or transmission, while also promoting sparse expansions. However, when the signal dimension is large, the computation of the frame measurements of a signal typically requires a large number of additions and multiplications, and this makes a frame decomposition intractable in applications with limited computing budget. To address this problem, in this paper, we introduce sparsity of a frame as a new paradigm. In our terminology, a sparse frame is a frame whose elements have a sparse representation in an orthonormal basis, thereby enabling low-complexity frame decompositions. To introduce a precise meaning of optimality, we take the sum of the numbers of vectors needed of this orthonormal basis when expanding each frame vector as sparsity measure. We then analyze the recently introduced algorithm Spectral Tetris for construction of unit norm tight frames and prove that the tight frames generated...

  10. Framing Effects: Dynamics and Task Domains

    Science.gov (United States)

    Wang

    1996-11-01

    The author examines the mechanisms and dynamics of framing effects in risky choices across three distinct task domains (i.e., life-death, public property, and personal money). The choice outcomes of the problems presented in each of the three task domains had a binary structure of a sure thing vs a gamble of equal expected value; the outcomes differed in their framing conditions and the expected values, raging from 6000, 600, 60, to 6, numerically. It was hypothesized that subjects would become more risk seeking, if the sure outcome was below their aspiration level (the minimum requirement). As predicted, more subjects preferred the gamble when facing the life-death choice problems than facing the counterpart problems presented in the other two task domains. Subjects' risk preference varied categorically along the group size dimension in the life-death domain but changed more linearly over the expected value dimension in the monetary domain. Framing effects were observed in 7 of 13 pairs of problems, showing a positive frame-risk aversion and negative frame-risk seeking relationship. In addition, two types of framing effects were theoretically defined and empirically identified. A bidirectional framing effect involves a reversal in risk preference, and occurs when a decision maker's risk preference is ambiguous or weak. Four bidirectional effects were observed; in each case a majority of subjects preferred the sure outcome under a positive frame but the gamble under a negative frame. In contrast, a unidirectional framing effect refers to a preference shift due to the framing of choice outcomes: A majority of subjects preferred one choice outcome (either the sure thing or the gamble) under both framing conditions, with positive frame augmented the preference for the sure thing and negative frame augmented the preference for the gamble. These findings revealed some dynamic regularities of framing effects and posed implications for developing predictive and testable

  11. Combining sky and earth: desert ants (Melophorus bagoti) show weighted integration of celestial and terrestrial cues.

    Science.gov (United States)

    Legge, Eric L G; Wystrach, Antoine; Spetch, Marcia L; Cheng, Ken

    2014-12-01

    Insects typically use celestial sources of directional information for path integration, and terrestrial panoramic information for view-based navigation. Here we set celestial and terrestrial sources of directional information in conflict for homing desert ants (Melophorus bagoti). In the first experiment, ants learned to navigate out of a round experimental arena with a distinctive artificial panorama. On crucial tests, we rotated the arena to create a conflict between the artificial panorama and celestial information. In a second experiment, ants at a feeder in their natural visually-cluttered habitat were displaced prior to their homing journey so that the dictates of path integration (feeder to nest direction) based on a celestial compass conflicted with the dictates of view-based navigation (release point to nest direction) based on the natural terrestrial panorama. In both experiments, ants generally headed in a direction intermediate to the dictates of celestial and terrestrial information. In the second experiment, the ants put more weight on the terrestrial cues when they provided better directional information. We conclude that desert ants weight and integrate the dictates of celestial and terrestrial information in determining their initial heading, even when the two directional cues are highly discrepant.

  12. Space-Time Reference Systems

    CERN Document Server

    Soffel, Michael

    2013-01-01

    The high accuracy of modern astronomical spatial-temporal reference systems has made them considerably complex. This book offers a comprehensive overview of such systems. It begins with a discussion of ‘The Problem of Time’, including recent developments in the art of clock making (e.g., optical clocks) and various time scales. The authors address  the definitions and realization of spatial coordinates by reference to remote celestial objects such as quasars. After an extensive treatment of classical equinox-based coordinates, new paradigms for setting up a celestial reference system are introduced that no longer refer to the translational and rotational motion of the Earth. The role of relativity in the definition and realization of such systems is clarified. The topics presented in this book are complemented by exercises (with solutions). The authors offer a series of files, written in Maple, a standard computer algebra system, to help readers get a feel for the various models and orders of magnitude. ...

  13. 基于同步参考坐标系的三相数字锁相环%Three-Phase Digital Phase-Locked Loop Based on Synchronous Reference Frame

    Institute of Scientific and Technical Information of China (English)

    洪小圆; 吕征宇

    2012-01-01

    基于同步参考坐标系的三相数字锁相环的动态性能取决于比例积分环节的参数设计、角频率静态偏置补偿误差及相位静态偏置补偿误差,本文通过构造李雅普诺夫函数验证了三相数字锁相环的非线性模型全局渐进稳定性,保证基于线性模型设计的PI参数的有效性;提出了基于过零检测的电网三相电压相序识别方法以保证角频率静态偏置的正确补偿,推导出了该方法下综合抗干扰能力最强的过零检测滞环幅值的求解公式,将相序识别时获得的初始相位用于锁相环的相位静态偏置补偿,使锁相环的调整时间缩短到过零点的等待时间及滞环电压弓J起的过零点误差调整时间。最后,仿真和实验证明了该方法的可行性。%The dynamic performance of three-phase digital phase-locked loop (PLL) based on synchronous reference frame depends on the proportional and integral (PI) parameters, compensation errors of angular frequency and phase angle static bias. The nonlinear model of the PLL is proved to be globally asymptotically stable with the design of Lyapunov function, which assures the validity of the PI parameters designed on the linear model. A grid phase sequence identification method based on zero-crossing detection is presented to guarantee the correct compensation of the angular frequency static bias. And the hysteresis voltage for zero-crossing detection is deduced to obtain the largest anti-interference margin. The initial phase angle is identified during phase sequence identification, and it could be used to compensate the phase angle static bias. Then the set-up time of the PLL could be greatly shortened to the waiting time of the zero-crossing and the set-up time of zero-crossing error due to the hysteresis voltage. Finally, the advantages mentioned above are verified by simulations and experiments.

  14. Algebra of timed frames

    NARCIS (Netherlands)

    Bergstra, J.A.; Fokkink, W.J.; Middelburg, C.A.

    2008-01-01

    Timed frames are introduced as objects that can form a basis of a model theory for discrete time process algebra. An algebraic setting for timed frames is proposed and results concerning its connection with discrete time process algebra are given. The presented theory of timed frames captures the ba

  15. 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 ...

  16. 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. *

  17. Reference Ellipsoid and Geoid in Chronometric Geodesy

    OpenAIRE

    Kopeikin, Sergei M.

    2016-01-01

    Chronometric geodesy applies general relativity to study the problem of the shape of celestial bodies including the earth, and their gravitational field. The present paper discusses the relativistic problem of construction of a background geometric manifold that is used for describing a reference ellipsoid, geoid, the normal gravity field of the earth and for calculating geoid's undulation (height). We choose the perfect fluid with an ellipsoidal mass distribution uniformly rotating around a ...

  18. 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 ...

  19. Efficient Short Boundary Detection & Key Frame Extraction using Image Compression

    Directory of Open Access Journals (Sweden)

    Shilpa. R. Jadhav Anup. V. Kalaskar Shruti Bhargava

    2011-10-01

    Full Text Available This paper present novel algorithm for efficient short boundary detection and key frames extraction using image compression. The algorithm differs from conventional methods mainly in the use of image segmentation and attention model.. Matching difference between two consecutive frames is computed with different weight. Shot boundaries are detected with automatic threshold. Key frame is extracted by using reference frame-based approach. Experimental results show improved performance of short boundary detection by using the proposed algorithms, and key frames represent shot content. And also satisfactorily image compression of result frame.

  20. IRREGULAR WAVELET FRAMES AND GABOR FRAMES

    Institute of Scientific and Technical Information of China (English)

    Ole Christensen; Sergio Favier; Felipe Zó

    2001-01-01

    Given g ∈ L2 (R), we consider irregular wavelet systems of theform {λ g(λj x-kb) }j z. kz, where λj >0 and b>0. Sufficient conditions for the wavelet system to constitute a frame for L2(R) are given. For a class of functions g ∈ L 2 (R) we prove that certain growth conditions on {λj} will lead to frames, and that some other types of sequences exclude the frame property. We also give a sufficient condition for a Gabor system {exib(j,x)g(x-λh)}jzn,kz to be a frame.CLC Number:O17 Document ID:AAuthor Resume:Ole Christensen;E-mail: Ole. Christensen@mat. dtu. dk Sergio Favier and Felipe Zó ;e-mails : sfavier@unsl. edu. ar fzo@unsl. edu. ar References:[1]Casaza,P.G. and Christensen,O.,Weyl-Heisenberg Frames for Subspaces of L2(R),Proc.Amer. Math. Soc. ,129(2001),145-154.[2]Casazza,P.G. and Christensen,O. ,Classifying Certain Irregular Gabor Frames,preprint[2]001.[3]Christensen,O. and Lindner,A. ,Lower Bounds for Finite Wavelet and Gabor Systems,Appr. Theory and Appl.,17(2001),17-31.[4]Chui,C.K. and Shi,X. ,Inequalities of Litdewood-Paley Type for Frames and Wavelets,SIAM J. Math. Anal. ,24:1(1993),263-277.[5]Daubechies,I. ,Ten Lectures on Wavelets,SIAM,Philadelphia,1992.[6]Favier,S. and Zalik,R. ,On the Stability of Frames and Riesz Bases,Appl. Comp. Ham.Anal. ,2(1995),160-173.[7]Feichtinger,H.G. and Strohmer,T. ,(Eds.),Gabor Analysis and Algorithms : Theory and Applications,Birkhauser,1998.[8]Heil,C.E. and Walnut,D.F. ,Continuous and Discrete Wavelet Transforms,SIAM Review,31:4(1989),628-666.[9]Sun,W. and Zhou,X. ,Irregular Wavelet Frames,Science in China (Series A),43:2(2000),122-127.Manuscript Received:2001年7月10日Manuscript Revised:2001年7月23日Published:2001年9月1日

  1. Frames and fusion frames in quantum optics

    Energy Technology Data Exchange (ETDEWEB)

    Jamiolkowski, Andrzej, E-mail: jam@fizyka.umk.p [Institute of Physics, Nicholas Copernicus University, 87-100 Torun (Poland)

    2010-03-01

    The main purpose of this paper is to show that the notions of frames and fusion frames introduced in non-harmonic Fourier analysis are also very natural in discussion of some basic problems in theory of open quantum systems and, in particular, in quantum optics. Frames are collections of vectors in a Hilbert space which assure a natural representation of each vector in the space, but may have infinitely many different representations for any given vector. For a given quantum system represented in a Hilbert space H the question of minimal number {eta} of observables Q{sub 1},..., Q{sub {eta}} whose expectation values at some instants t{sub 1},...,t{sub p} determine the statistical state of the system is discussed. We assume that the time evolution of the system in question is governed by a semigroup of linear transformations with generator L.

  2. Time delay control of power converters: Mixed frame and stationary-frame variants

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Loh, P.C.; Tang, Y.;

    2008-01-01

    In this paper, a mixed-frame and a stationary-frame time delay current controller are proposed for high precision reference tracking and disturbance rejection of power converters. In particular, the controllers use a proportional-resonant regulator in the stationary frame for regulating...... 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 time delay control path in either the synchronous...... or stationary frame, whose inherent feedback and feedforward structure can be proven to resemble a bank of resonant filters in either reference frames. Unlike other existing controllers, the proposed time delay controllers function by introducing multiple resonant peaks at only those harmonic frequencies...

  3. 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.

  4. Discretization of Continuous Frame

    Indian Academy of Sciences (India)

    A Fattahi; H Javanshiri

    2012-05-01

    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 $\\mathcal{H}$ which has a countable reconstruction formula. Among the other results, we characterize the relationship between this new concept and other known continuous frames. Finally, we state and prove the assertions of the stability of perturbation in this concept.

  5. 正负面建议呈现方式和调节匹配对冲动性购买行为的影响%The Effect of Framing Message of Reference Group's Proposal and Regulatory Fit on Impulse Buying Behavior

    Institute of Scientific and Technical Information of China (English)

    梁承磊; 李秀荣

    2012-01-01

    本文采用架构为2(参照群体建议的信息框架:正面框架/负面框架)×2(调节焦点:促进型焦点/防御型焦点)×2(认知需求:高认知需求/低认知需求)的组间设计,分析参照群体建议的信息框架、调节匹配和认知需求对消费者冲动性购买行为的影响。研究结果发现:在调节匹配的情况下,消费者冲动性购买的意图和行为程度更高,且认知需求会干扰调节匹配对冲动性购买意图和行为的影响效果。%A2(framing effect of reference group's proposal:positive/negative) × 2(regulatory focus:promotion/prevention) × 2(need for cognition:high/low) experiment is conducted to analyze the effect of framing effect of reference group's proposal,regulatory fit,and need for cognition on impulse buying.The experiment reveals that consumers respond differently to various framing message of reference group's proposal.When regulatory fit appears,consumers have more positive purchase intention and impulse buying on products.The need for cognition will moderate the effect of regulatory fit on purchase intention and impulse buying.

  6. Celestial symbolism in the Vučedol culture

    Directory of Open Access Journals (Sweden)

    Aleksandar Durman

    2001-12-01

    Full Text Available The article presents the Vučedol Culture conception of the world, as shown on their vessels, particularly the terrines and the vessels developed from them – referred to as censers. They had more of a ritual than a practical role. Particular attention is drawn to the pot with the calendar image.

  7. Forecasting scenarios of collision catastrophes produced by celestial body falls

    Science.gov (United States)

    Shor, V.; Kochetova, O.; Chernetenko, Y.; Zheleznov, N.; Deryugin, V.; Zaitsev, A.

    2014-07-01

    The subject under discussion arose in the course of developing a computer program, which gives the possibility for numerical and graphical modeling of the scenarios of catastrophes caused by collisions of cosmic bodies with the Earth. It is expected that this program can be used for computer-assisted training of the personnel of units of the Ministry for Emergency Situations in the case of a situation caused by the fall of a celestial body on the Earth. Also, it is anticipated that the program can be used in real situations when a dangerous body is discovered on an orbit leading to an imminent collision with the Earth. From the scientific point of view, both variants of use require solving of analogous tasks. In what follows, we discuss both variants. 1. The computation of the circumstances for a fall on the Earth (or approach within short distance) of a real body begins with the determination of its orbit from the observations available using the least-squares method. The mean square error of the representation of the observations on the base of the initial values of the coordinates and the velocities is computed, as well as their covariance matrix. Then, the trajectory of the body's motion is followed by numerical integration starting from the osculating epoch to the collision with the Earth or to its flyby. The computer program takes into account the various cases: at the initial moment, the body can move away from or approach the Earth, it can be outside the sphere of action or inside it. At the moment, when the body enters the sphere of action, the coordinates of the center of the dispersion ellipse on the target plane are computed as well as the dimensions of its axes. Using these data, the probability of collision with the Earth is calculated. Then, the point of penetration of the body into the Earth's atmosphere at a given height above the level of the Earth geoid is determined. In case the body is passing by the Earth, the minimum distance of the body from

  8. 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.

  9. The Gravitational Effects of a Celestial Body with Magnetic Charge and Moment

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The gravitational effects (precession of charge-less particles and deflection of light) in the gravitational field of a celestial body with magnetic charge and moment (CM)are investigated. We found that the magnetic charge always weakens the pure Schwarzschild effects, while the magnetic dipole moment deforms the effects in a more complicated way.

  10. Irregular wavelet frames

    Institute of Scientific and Technical Information of China (English)

    孙文昌; 周性伟

    2000-01-01

    For the non-band-limited function ψ, a sufficient condition is presented under whichis a frame for L2(R). The stability of these frames is studied. For the wavelets frequently used in signal processing, some concrete results are given.

  11. Irregular wavelet frames

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    For the non-band-limited function ψ, a sufficient condition is presented under which{√sjψ(sj·-kb)} is a frame for L2(R). The stability of these frames is studied. For the wavelets frequently used in signal processing, some concrete results are given.

  12. 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…

  13. 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…

  14. Rotating space elevators: Physics of celestial scale spinning strings

    Science.gov (United States)

    Knudsen, Steven; Golubović, Leonardo

    2014-11-01

    We explore classical and statistical mechanics of a novel dynamical system, the Rotating Space Elevator (RSE) (L. Golubović, S. Knudsen, EPL 86, 34001 (2009)). The RSE is a double rotating floppy string reaching extraterrestrial locations. Objects sliding along the RSE string (climbers) do not require internal engines or propulsion to be transported far away from the Earth's surface. The RSE thus solves a major problem in space elevator science, which is how to supply energy to the climbers moving along space elevator strings. The RSE can be made in various shapes that are stabilized by an approximate equilibrium between the gravitational and inertial forces acting in a double rotating frame associated with the RSE. This dynamical equilibrium is achieved by a special ("magical") form of the RSE mass line density derived in this paper. The RSE exhibits a variety of interesting dynamical phenomena explored here by numerical simulations. Thanks to its special design, the RSE exhibits everlasting double rotating motion. Under some conditions, however, we find that the RSE may undergo a morphological transition to a chaotic state reminiscent of fluctuating directed polymers in the realm of the statistical physics of strings and membranes.

  15. Informative-frame filtering in endoscopy videos

    Science.gov (United States)

    An, Yong Hwan; Hwang, Sae; Oh, JungHwan; Lee, JeongKyu; Tavanapong, Wallapak; de Groen, Piet C.; Wong, Johnny

    2005-04-01

    Advances in video technology are being incorporated into today"s healthcare practice. For example, colonoscopy is an important screening tool for colorectal cancer. Colonoscopy allows for the inspection of the entire colon and provides the ability to perform a number of therapeutic operations during a single procedure. During a colonoscopic procedure, a tiny video camera at the tip of the endoscope generates a video signal of the internal mucosa of the colon. The video data are displayed on a monitor for real-time analysis by the endoscopist. Other endoscopic procedures include upper gastrointestinal endoscopy, enteroscopy, bronchoscopy, cystoscopy, and laparoscopy. However, a significant number of out-of-focus frames are included in this type of videos since current endoscopes are equipped with a single, wide-angle lens that cannot be focused. The out-of-focus frames do not hold any useful information. To reduce the burdens of the further processes such as computer-aided image processing or human expert"s examinations, these frames need to be removed. We call an out-of-focus frame as non-informative frame and an in-focus frame as informative frame. We propose a new technique to classify the video frames into two classes, informative and non-informative frames using a combination of Discrete Fourier Transform (DFT), Texture Analysis, and K-Means Clustering. The proposed technique can evaluate the frames without any reference image, and does not need any predefined threshold value. Our experimental studies indicate that it achieves over 96% of four different performance metrics (i.e. precision, sensitivity, specificity, and accuracy).

  16. Framing effects over time: comparing affective and cognitive news frames

    NARCIS (Netherlands)

    Lecheler, S.; Matthes, J.

    2012-01-01

    A growing number of scholars examine the duration of framing effects. However, duration is likely to differ from frame to frame, depending on how strong a frame is. This strength is likely to be enhanced by adding emotional components to a frame. By means of an experimental survey design (n = 111),

  17. FrameLink软件

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Blackmagic Design在NAB2005新推出的FrameLink软件,将在DeckLink系列视频卡中免费提供。它支持DPX文件格式,兼容电影工作中的数字中间片(DI)环节。FrameLink允许在保持Quick-Time和AVI文件的速度和灵活性的同时兼容DPX文件。

  18. Emergent Bilinguals: Framing Students as Statistical Data?

    Science.gov (United States)

    Koyama, Jill; Menken, Kate

    2013-01-01

    Immigrant youth who are designated as English language learners in American schools--whom we refer to as "emergent bilinguals"--are increasingly framed by numerical calculations. Utilizing the notion of assemblage from actor-network theory (ANT), we trace how emergent bilinguals are discursively constructed by officials, administrators,…

  19. Suppression of DFIG Stator Output Power Fluctuation Adapted to Complicated Grid Conditions in The α、β Reference Frame%两相静止坐标系下DFIG适应复杂电网环境的定子输出功率波动抑制

    Institute of Scientific and Technical Information of China (English)

    李俊卿; 戴斌

    2016-01-01

    针对电网电压不平衡且同时含有5次、7次谐波的复杂电网环境对双馈风力发电机组( DFIG)定子输出功率的不良影响,在两相静止α、β坐标系中对DFIG适应复杂电网环境的定子输出有功和无功功率波动抑制控制策略进行了研究. 分析了复杂电网环境下DFIG在两相静止α、β坐标系中的定子输出有功、无功功率波动成分,计算出能抑制DFIG定子输出有功、无功功率中2倍频和6倍频波动成分的转子电流参考指令. 通过MATLAB/Simulink仿真验证了所提控制策略的有效性.%At the view of the harmful effects on DFIG stator output power caused by unbalanced grid voltage which also contains fifth order harmonic and seventh order harmonic, the DFIG stator output active and reactive power fluctuation suppressing control strategy was studied in the α、β reference frame. The rotor current reference instructions that suppressed the 2-doubling and 6-doubling fluctuant components of DFIG stator output active and reactive power was calculated in the α、β reference frame based on analysis of DFIG stator output active and reactive power fluctuant components. The effectiveness of the control strategy proposed was proved through MATLAB/Simulink simulation.

  20. Type of frame dependence: variation in media frames affecting attitudes via audience frames

    NARCIS (Netherlands)

    van Drunen, A.S.; Boomgaarden, H.G.; Vliegenthart, R.

    2012-01-01

    In this paper two suggested processes of framing theory (Scheufele, 1999) are tested: frame setting (media affecting audience frames) and the individual effects process (audience frames affecting attitudes or behavior). Media frames may affect opinions and behavior, however these effects are not dir

  1. Heavenly Networks. Celestial Maps and Globes in Circulation between Artisans, Mathematicians, and Noblemen in Renaissance Europe.

    Science.gov (United States)

    Gessner, Samuel

    2015-01-01

    The aim of this paper is to examine the iconography on a set of star charts by Albrecht Dürer (1515), and celestial globes by Caspar Vopel (1536) and Christoph Schissler (1575). The iconography on these instruments is conditioned by strong traditions which include not only the imagery on globes and planispheres (star charts), but also ancient literature about the constellations. Where this iconography departs from those traditions, the change had to do with humanism in the sixteenth century. This "humanistic" dimension is interwoven with other concerns that involve both "social" and "technical" motivations. The interplay of these three dimensions illustrates how the iconography on celestial charts and globes expresses some features of the shared knowledge and shared culture between artisans, mathematicians, and nobles in Renaissance Europe.

  2. UBVRI Photometric Standard Stars Around the Celestial Equator: Updates and Additions

    CERN Document Server

    Landolt, Arlo U

    2009-01-01

    New broadband UBVRI photoelectric observations on the Johnson-Kron-Cousins photometric system have been made of 202 stars around the sky, and centered at the celestial equator. These stars constitute both an update of and additions to a previously published list of equatorial photometric standard stars. The list is capable of providing, for both celestial hemispheres, an internally consistent homogeneous broadband standard photometric system around the sky. When these new measurements are included with those previously published by Landolt (1992), the entire list of standard stars in this paper encompasses the magnitude range 8.90 < V < 16.30, and the color index range -0.35 < (B - V) < +2.30.

  3. The impact of celestial pole offset modelling on VLBI UT1 Intensive results

    CERN Document Server

    Malkin, Zinovy

    2011-01-01

    Very Long Baseline Interferometry (VLBI) Intensive sessions are scheduled to provide operational Universal Time (UT1) determinations with low latency. UT1 estimates obtained from these observations heavily depend on the model of the celestial pole motion used during data processing. However, even the most accurate precession-nutation model, IAU 2000/2006, is not accurate enough to realize the full potential of VLBI observations. To achieve the highest possible accuracy in UT1 estimates, a celestial pole offset (CPO), which is the difference between the actual and modelled precession-nutation angles, should be applied. Three CPO models are currently available for users. In this paper, these models have been tested and the differences between UT1 estimates obtained with those models are investigated. It has been shown that neglecting CPO modelling during VLBI UT1 Intensive processing causes systematic errors in UT1 series of up to 20 microarcseconds. It has been also found that using different CPO models causes...

  4. A new method of single celestial-body sun positioning based on theory of mechanisms

    Institute of Scientific and Technical Information of China (English)

    Zhang Wei; Xu Xiaofeng; Wu Yuanzhe

    2016-01-01

    Considering defects of current single celestial-body positioning methods such as discon-tinuity and long period, a new sun positioning algorithm is herein put forward. Instead of tradi-tional astronomical spherical trigonometry and celestial coordinate system, the proposed new positioning algorithm is built by theory of mechanisms. Based on previously derived solar vector equations (from a C1R2P2 series mechanism), a further global positioning method is developed by inverse kinematics. The longitude and latitude coordinates expressed by Greenwich mean time (GMT) and solar vector in local coordinate system are formulated. Meanwhile, elimination method of multiple solutions, errors of longitude and latitude calculation are given. In addition, this algo-rithm has been integrated successfully into a mobile phone application to visualize sun positioning process. Results of theoretical verification and smart phone’s test demonstrate the validity of pre-sented coordinate’s expressions. Precision is shown as equivalent to current works and is acceptable to civil aviation requirement. This new method solves long-period problem in sun sight running fix-ing and improves applicability of sun positioning. Its methodology can inspire development of new sun positioning device. It would be more applicable to be combined with inertial navigation systems for overcoming discontinuity of celestial navigation systems and accumulative errors of inertial nav-igation systems.

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

    Indian Academy of Sciences (India)

    Mohammad Sadegh Asgari

    2009-06-01

    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 under a bounded surjective operator.

  6. Comparative Analysis of Frames with Varying Inertia

    Directory of Open Access Journals (Sweden)

    Prerana Nampalli

    2015-01-01

    Full Text Available This paper presents an elastic seismic response of reinforced concrete frames with 3 variations of heights, i.e. (G+2, (G+4, (G+6 storey models are compared for bare frame and frame with brick infill structures which have been analyzed for gravity as well as seismic forces and their response is studied as the geometric parameters varying from view point of predicting behavior of similar structures subjected to similar loads or load combinations. In this study, two different cases are selected i.e. frames with prismatic members and frames with non-prismatic members. The structural response of various members when geometry changes physically, as in case of linear and parabolic haunches provided beyond the face of columns at beam column joints or step variations as in case of stepped haunches was also studied. Frames have been analyzed statically as well as dynamically using ETABS-9.7.4 software referring IS: 456-2000, IS: 1893 (Part-12002 and the results so obtained are grouped into various categories

  7. Framing financial culture

    DEFF Research Database (Denmark)

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

    2014-01-01

    /methodology/approach – A conceptual framework that combines modern framing theory, and classical stasis theory is applied to the rhetorical struggles over the meaning of “Liborgate.” Findings – While rhetorical struggles over “Liborgate” overtly center on the issue of who is to blame, an analysis of the argumentative relations...... 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....

  8. Conformal frames in cosmology

    CERN Document Server

    Domènech, Guillem

    2016-01-01

    From higher dimensional theories, e.g. string theory, one expects the presence of non-minimally coupled scalar fields. We review the notion of conformal frames in cosmology and emphasize their physical equivalence, which holds at least at a classical level. Furthermore, if there is a field, or fields, which dominates the universe, as it is often the case in cosmology, we can use such notion of frames to treat our system, matter and gravity, as two different sectors. On one hand, the gravity sector which describes the dynamics of the geometry and on the other hand the matter sector which has such geometry as a playground. We use this interpretation to build a model where the fact that a curvaton couples to a particular frame metric could leave an imprint in the CMB.

  9. 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...... by the participants’ religion. Specifically, analyses revealed that Christians demonstrated more negative implicit attitudes toward immigrants than Muslims. Conversely, Atheists demonstrated more negative implicit attitudes toward Muslims than Atheists. These results suggest a complex relationship between religion...

  10. Promotional Frames' Influence on Price Perceptions of Two Apparel Products.

    Science.gov (United States)

    Stanforth, Nancy; Lennon, Sharron; Shin, Jung Im

    2001-01-01

    A study explored the differences in price perceptions of two apparel products when promotions were framed as either a price discount or a gift-with-purchase. The majority preferred the discount. Results illustrate the importance of promotional framing in forming consumer price perceptions. (Contains 30 references.) (Author/JOW)

  11. The Virtual Reference Librarian's Handbook.

    Science.gov (United States)

    Lipow, Anne Grodzins

    This book is a practical guide to librarians and their administrators who are thinking about or in the early stages of providing virtual reference service. Part 1, "The Decision to Go Virtual," provides a context for thinking about virtual reference, including the benefits and problems, getting in the virtual frame of mind, and shopping…

  12. Hybrid Reinforced Concrete Frame Building with Pumice Brick Masonry Infill under Static Lateral Loading

    Directory of Open Access Journals (Sweden)

    Akmaluddin

    2012-08-01

    Full Text Available The purpose of this study is to investigate the behaviour of hybrid reinforced concrete frame with pumice brick masonry infill under static lateral loading. The term hybrid herein is referred to the frame composed of precast block masonry unit and cast in-place reinforced concrete beams. Parameters considered in this study were frame opening representing doors and windows commonly used in the wall system. Six types of frame namely FS, FB, FDE, FDC, FWE and FWC designation for solid frame, bare frame, frame with door opening at edge, frame with door opening at centre, frame with window opening at edge and frame with window opening at centre respectively were considered. Test results indicated that the FS has a maximum lateral strength greater than that of FB. The lateral strength of FS was about 3.68 of FB. The frames with various openings have lateral strength nearly 2.3 of lateral strength of the bare frame, FB. Ductility factor of the frames varied from 2.4 to 4.92. The residual strength of the frame with openings were varies between 2.33 and 3.35 of the bare frame. The stiffness of the infilled frames with opening were varied from 3.56 to 3.67 of the bare frame. The presence of openings in the infilled frame did not affect the frame stiffness considerably.

  13. 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...... 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....

  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....... It was found that the specific damages made to the vapour barrier as part of the test did not have any provable effect on the moisture content. In general elements with an intact vapour barrier did not show a critical moisture content at the wind barrier after four years of exposure....

  15. Framings for graph hypersurfaces

    CERN Document Server

    Brown, Francis

    2013-01-01

    We present a method for computing the framing on the cohomology of graph hypersurfaces defined by the Feynman differential form. This answers a question of Bloch, Esnault and Kreimer in the affirmative for an infinite class of graphs for which the framings are Tate motives. Applying this method to the modular graphs of Brown and Schnetz, we find that the Feynman differential form is not of Tate type in general. This finally disproves a folklore conjecture stating that the periods of Feynman integrals of primitive graphs in phi^4 theory factorise through a category of mixed Tate motives.

  16. The Massive Schwinger Model in a Fast Moving Frame

    OpenAIRE

    1998-01-01

    We present a non-perturbative study of the massive Schwinger model. We use a Hamiltonian approach, based on a momentum lattice corresponding to a fast moving reference frame, and equal time quantization.

  17. 以时间为参照系的训练理念在百米跑运动员专项速度训练中的应用%Application of temporal frame of reference to 100 m sprint speed training

    Institute of Scientific and Technical Information of China (English)

    戴兴鸿; 詹建国

    2014-01-01

    In traditional sprint speed training,both coaches and athletes take the distance as frame of reference,in which speed training is carried out by running different short distances. However,this method cannot help athletes achieve the desired results of improving the ability to accelerate and the rhythm controlling ability of the whole distance. In the training practice,we educate the training i-dea that takes the time as the frame of reference according to the characteristics of energy supply and the whole rhythm for sprint. Research shows that it is helpful to improve the athlete′s speed ability and controlling ability of the whole rhythm in sprint speed training.%在传统的百米跑速度训练中,教练员和运动员都是以距离为参照系进行专项速度训练,即通过快速跑不同的短距离进行速度训练。这种速度训练手段对运动员的加速能力以及运动员对全程节奏的控制能力的提高并不能达到理想的效果。在训练实践中,我们根据百米跑运动的能量供应特点和全程节奏特点,灌输以时间为参照系的训练理念。研究表明,优秀女子百米跑运动员速度训练中运用以时间为参照系的训练理念有助于提高运动员的速度能力以及提高运动员对全程的控制能力。

  18. 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

  19. 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)....

  20. Finite Operator-Valued Frames

    CERN Document Server

    Meng, Bin

    2010-01-01

    Operator-valued frames are natural generalization of frames that have been used in quantum computing, packets encoding, etc. In this paper, we focus on developing the theory about operator-valued frames for finite Hilbert spaces. Some results concerning dilation, alternate dual, and existence of operator-valued frames are given. Then we characterize the optimal operator-valued frames under the case which one packet of data is lost in transmission. At last we construct the operator-valued frames $\\{V_j\\}_{j=1}^m$ with given frame operator $S$ and satisfying $V_jV_j^*=\\alpha_jI$, where $\\alpha_j's$ are positive numbers.

  1. 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...

  2. Framing difficulties in quantum mechanics

    CERN Document Server

    Modir, Bahar; Sayre, Eleanor C

    2016-01-01

    Students' difficulties in quantum mechanics may be the result of unproductive framing and not fundamental inability to solve the problems or misconceptions about physics content. We observed groups of students solving quantum mechanics problems in an upper-division physics course. Using the lens of the epistemological framing, we investigated four frames in our observational data: algorithmic math, conceptual math, algorithmic physics, and conceptual physics. We then used our framework to seek an underlying structure to the long lists of published difficulties that span many topics in quantum mechanics. We mapped descriptions of published difficulties into errors in epistemological framing and resource use. We analyzed descriptions of students' problem solving to find their frames, and compared students' framing to framing (and frame shifting) required by problem statements. We found three categories of error: mismatches between students' framing and problem statement framing; inappropriate or absent transiti...

  3. Framing Evolution Discussion Intellectually

    Science.gov (United States)

    Oliveira, Alandeom W.; Cook, Kristin; Buck, Gayle A.

    2011-01-01

    This study examines how a first-year biology teacher facilitates a series of whole-class discussions about evolution during the implementation of a problem-based unit. A communicative theoretical perspective is adopted wherein evolution discussions are viewed as social events that the teacher can frame intellectually (i.e., present or organize as…

  4. 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...

  5. 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 understand

  6. 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...

  7. Finite Operator-Valued Frames

    OpenAIRE

    Meng, Bin

    2010-01-01

    Operator-valued frames are natural generalization of frames that have been used in quantum computing, packets encoding, etc. In this paper, we focus on developing the theory about operator-valued frames for finite Hilbert spaces. Some results concerning dilation, alternate dual, and existence of operator-valued frames are given. Then we characterize the optimal operator-valued frames under the case which one packet of data is lost in transmission. At last we construct the operator-valued fram...

  8. ON THE STABILITY OF FUSION FRAMES (FRAMES OF SUBSPACES)

    Institute of Scientific and Technical Information of China (English)

    Mohammad Sadegh Asgari

    2011-01-01

    A frame is an orthonormal basis-like collection of vectors in a Hilbert space,but need not be a basis or orthonormal.A fusion frame (frame of subspaces) is a frame-like collection of subspaces in a Hilbert space,thereby constructing a frame for the whole space by joining sequences of frames for subspaces.Moreover the notion of fusion frames provide a framework for applications and providing efficient and robust information processing algorithms.In this paper we study the conditions under which removing an element from a fusion frame,again we obtain another fusion frame.We give another proof of[5,Corollary 3.3(iii)]with extra information about the bounds.

  9. 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.

  10. 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....... In order to estimate performances, detailed thermal calculations were performed in four successive steps including solar energy and light transmittance in addition to heat loss and supplemented with a simplified structural calculation of frame load capacity and deflection. Based on these calculations, we...... 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...

  11. 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…

  12. 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....... The article draws on the socio-technical approach to mobilities studies in order to reassemble the decision-making process in three European cases: Bergen, Angers, and Bern. This article provides insights into the political, discursive and material production of light rail mobilities in a European context....... It identifies the planning rationales behind the systems and the policies that have been supportive of this light rail vision. Finally, the article identifies the practical challenges and potentials that have been connected to the different local frames of light rail mobility which can be used in future...

  13. 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...... were removed in some of the elements to simulate damaged vapour barriers. The condition of the wind barriers of elements with intact vapour barriers was inspected from the inside after four years of exposure. This paper presents results with emphasis on the moisture conditions behind the wind barrier....... It was found that the specific damages made to the vapour barrier as part of the test did not have any provable effect on the moisture content. In general elements with an intact vapour barrier did not show a critical moisture content at the wind barrier after four years of exposure....

  14. Framing the Manager

    DEFF Research Database (Denmark)

    Holmgreen, Lise-Lotte

    2013-01-01

    Genres are ways for organisations of discursively interacting with the surrounding world, with the aim of achieving specific disciplinary goals (Bhatia 2004). As such, the management job ad has the objective of finding the right candidate for the management job advertised (Norlyk 2006...... predominant conceptual models or frames for leadership, the ‘goal-oriented motivator’ model and the ‘empathic communicator’ model, which frame the position and the candidate, from the discursive and metaphorical construction of the ad to the actual hiring of the new employee. While there may be little new...... in this realisation, the fact that one of the two models, the ‘goal-oriented motivator’ model, seems to be monopolising the genre raises a number of issues that need to be addressed: How is this model realised conceptually and linguistically? Why does this model continue to be the Danish business world’s preferred...

  15. Concepts and Contexts – Argumentative Forms of Framing

    DEFF Research Database (Denmark)

    Gabrielsen, Jonas; Nørholm Just, Sine; Bengtsson, Mette

    2011-01-01

    The notion of framing has become central in the field of argumentation. The question is, however, what we gain from studying the process of argumentation through framing, since framing is itself a broad concept in need of specification. Different traditions understand the term differently......, and it is necessary to determine what argumentative forms the concept of framing actually covers. In this paper we argue that framing refers to at least two different argumentative forms. One is an internal definition of the concepts in question; the other is an external shift in the context of the case. In making...... this argument we combine theories of framing with the classical rhetorical theory of the stases, more precisely status definitio and status translatio. Our focus is primarily theoretical, but we illustrate our points by means of examples taken from public debates on the value of real estate....

  16. Electronic Photo Frame

    OpenAIRE

    Ni, Ze

    2010-01-01

    The goal of the thesis work is to develop a photo frame device. Hence, it supplies a set of feasible solutions from hardware to software. Relatively speaking, the project chiefly focuses on software-oriented development. It is concerned with building the bootloader, the Linux Kernel, related drivers, file systems, and applications. After that, they are integrated together to form a brand-new embedded Linux distribution. The distribution is specifically designed to meet the requirement of the ...

  17. 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({\\bo...

  18. Spectrum of the Anomalous Microwave Emission in the North Celestial Pole with WMAP 7-Year data

    CERN Document Server

    Bonaldi, Anna; 10.1155/2012/853927

    2013-01-01

    We estimate the frequency spectrum of the diffuse anomalous microwave emission (AME) on the North Celestial Pole (NCP) region of the sky with the Correlated Component Analysis (CCA) component separation method applied to WMAP 7-yr data. The NCP is a suitable region for this analysis because the AME is weakly contaminated by synchrotron and free-free emission. By modeling the AME component as a peaked spectrum we estimate the peak frequency to be $21.7\\pm0.8$\\,GHz, in agreement with previous analyses which favored $\

  19. Brightness and color of the integrated starlight at celestial, ecliptic and galactic poles

    CERN Document Server

    Nawar, S; Mikhail, J S; Morcos, A B

    2010-01-01

    From photoelectric observations of night sky brightness carried out at Abu-Simbel, Asaad et al. (1979) have obtained values of integrated starlight brightness at different Galactic latitudes. These data have been used in the present work to obtain the brightness and color of the integrated starlight at North and South Celestial, Ecliptic and Galactic Poles. The present values of the brightness are expressed in S10 units and mag/arcsec2. Our results have been compared with that obtained by other investigators using photometric and star counts techniques. The B-V and B-R have been calculated and the results are compared with that obtained by other investigators.

  20. Method of separation of celestial gamma-ray bursts from solar flares

    Energy Technology Data Exchange (ETDEWEB)

    Chuang, K.W.; White, R.S. (Institute of Geophysics and Planetary Physics, UC Riverside, California 92521 (United States)); Klebesadel, R.W.; Laros, J.G. (Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States))

    1991-09-01

    We recently discovered 217 new'' celestial gamma-ray burst candidates from the new'' burst search of the PVO real time data base.[sup 1] The burst search covered the time period from September 1978 to July 1988. Sixty were confirmed by at lest on other spacecraft, e.g., ISEE-3, V-11, V-12, etc. None triggered the PVO high time resolution memory. In this paper we describe a new algorithm based ont eh relationship between time width [ital T][sub [ital w

  1. 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

  2. On the accuracy of approximation of motion of a small celestial body by intermediate perturbed orbits calculated on the basis of three position vectors and three observations

    Science.gov (United States)

    Shefer, V. A.; Shefer, O. V.

    2016-05-01

    Intermediate perturbed orbits, which were proposed earlier by the first author and are calculated based on three position vectors and three measurements of angular coordinates of a small celestial body, are examined. Provided that the reference time interval encompassing the measurements is short, these orbits are close in the accuracy of approximation of actual motion to an orbit with fourth-order tangency. The shorter the reference time interval is, the better is the approximation. The laws of variation of the errors of methods for constructing such intermediate orbits with the length of the reference time interval are formulated. According to these laws, the rate of convergence of the methods to an exact solution in the process of shortening of the reference time interval is, in general, three orders of magnitude higher than that of conventional methods relying on an unperturbed Keplerian orbit. The considered orbits are among the most accurate of their class that is defined by the order of tangency. The obtained theoretical results are verified by numerical experiments on determining the orbit of 99942 Apophis.

  3. 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.

  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, ... as HealthDay. Our license agreements do not permit framing of their content from our site. For more ...

  5. Hybrid Synchronous/Stationary Reference Frame Filtering based PLL

    DEFF Research Database (Denmark)

    Golestan, Saeed; Guerrero, Josep M.; Abusorrah, Abdullah

    2015-01-01

    Designing an effective phase-locked loop (PLL) for three-phase applications is the objective of this paper. The designed PLL structure is able to provide an accurate estimation of grid voltage frequency and phase even in the presence of all harmonic components of both positive and negative...... sequences and dc offset in its input. It addition to offer a high disturbance rejection capability, the suggested PLL structure has a fast transient response and provides a settling time of around two cycles of fundamental frequency. The effectiveness of suggested PLL structure is confirmed using numerical...

  6. Intrinsic Frames of Reference and Egocentric Viewpoints in Scene Recognition

    Science.gov (United States)

    Mou, Weimin; Fan, Yanli; McNamara, Timothy P.; Owen, Charles B.

    2008-01-01

    Three experiments investigated the roles of intrinsic directions of a scene and observer's viewing direction in recognizing the scene. Participants learned the locations of seven objects along an intrinsic direction that was different from their viewing direction and then recognized spatial arrangements of three or six of these objects from…

  7. 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.

  8. Prolonged weightlessness, reference frames and visual symmetry detection.

    Science.gov (United States)

    Leone, G; de Schonen, S; Lipshits, M

    1998-01-01

    We evaluated the influence of prolonged weightlessness on the performance of three cosmonauts to bilateral symmetry detection in the course of a 15-day-long Russian-French mission CASSIOPEE 96 aboard the MIR station. We tested the influence of weightlessness on subjects' performance as a function of the retinal orientation of axis of symmetry. as a function of type of stimuli (closed versus multi-elements shapes) and as a function of visual field presentation (at fixation, left visual field. right visual field). The results indicate firstly a difference between presentation at fixation versus away of fixation. Away of fixation, no effect of microgravity on performance was shown. A hypothesis of hemispheric specialization for symmetry detection was not supported as well. At fixation, an effect of micro-gravity was shown and more interestingly, the effect was quite different as a function of type of shapes used. suggesting that symmetry detection is a multiple-stage process.

  9. 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.

  10. 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…

  11. On one-way Doppler measurements of space craft and celestial objects

    Science.gov (United States)

    Jochim, E. F. M.

    2010-01-01

    The orbital velocity of a spacecraft and other celestial objects is monitored by observing the Doppler frequency shift of the signals received at the ground station. This is possible one-way in case the transmitted frequency is stable enough. In most spacecraft a calibrated transponder allows two-way Doppler frequency registrations. In general, the factor 2 is expected as the quotient between two- and one-way frequencies. However, this is no longer the case when the motion of the observed object deviates from the orbit as predicted. Frequency differences appear. Porsche (1999) has published a formula to describe these differences based on the assumption of a double projection of the true velocity vector. In the present paper a more sophisticated analysis of the influence of state errors on the track-ing results is deduced. This theory has been tested by the Doppler measurements during flybys of the comet space probe GIOTTO penetrating through the comae of the comets P/Halley and P/Grigg-Skjellerup. One-way Doppler measurements of the low Earth satellites CHAMP and TERRASAR-X show a tendency for the applicability of this approach. Finally, some conse-quences for the observation of other celestial objects are discussed.

  12. Optimization design about gimbal structure of high-precision autonomous celestial navigation tracking mirror system

    Science.gov (United States)

    Huang, Wei; Yang, Xiao-xu; Han, Jun-feng; Wei, Yu; Zhang, Jing; Xie, Mei-lin; Yue, Peng

    2016-01-01

    High precision tracking platform of celestial navigation with control mirror servo structure form, to solve the disadvantages of big volume and rotational inertia, slow response speed, and so on. It improved the stability and tracking accuracy of platform. Due to optical sensor and mirror are installed on the middle-gimbal, stiffness and resonant frequency requirement for high. Based on the application of finite element modality analysis theory, doing Research on dynamic characteristics of the middle-gimbal, and ANSYS was used for the finite element dynamic emulator analysis. According to the result of the computer to find out the weak links of the structure, and Put forward improvement suggestions and reanalysis. The lowest resonant frequency of optimization middle-gimbal avoid the bandwidth of the platform servo mechanism, and much higher than the disturbance frequency of carrier aircraft, and reduces mechanical resonance of the framework. Reaching provides a theoretical basis for the whole machine structure optimization design of high-precision of autonomous Celestial navigation tracking mirror system.

  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. The Levels of Visual Framing

    Science.gov (United States)

    Rodriguez, Lulu; Dimitrova, Daniela V.

    2011-01-01

    While framing research has centered mostly on the evaluations of media texts, visual news discourse has remained relatively unexamined. This study surveys the visual framing techniques and methods employed in previous studies and proposes a four-tiered model of identifying and analyzing visual frames: (1) visuals as denotative systems, (2) visuals…

  15. ENHANCEMENT STRATEGIES FOR FRAME-TO-FRAME UAS STEREO VISUAL ODOMETRY

    Directory of Open Access Journals (Sweden)

    J. Kersten

    2016-06-01

    Full Text Available 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.

  16. Synchronization and Inertial Frames

    CERN Document Server

    Viazminsky, C P

    1999-01-01

    In classical mechanics, a procedure for simultaneous synchronization in all inertial frames is consistent with the Galilean transformation. However, if one attempts to achieve such a synchronization utilizing light signals, he will be facing in the first place the break down of simultaneity, and secondly, a self-contradictory transformation that has the Lorentz transformation, or its confinement to the velocity of light, as the only possible ways that resolve the contradiction. The current work constitutes a smooth transition from traditional to relativistic vision of mechanics, and therefore is quite appealing from pedagogical point of view.

  17. 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.

  18. Framing a Bank

    DEFF Research Database (Denmark)

    Holmgreen, Lise-Lotte

    2012-01-01

    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 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 discursive construction. This article will focus on the role of this interaction in metaphorically and conceptually framing a large...

  19. 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.

  20. Pulsars as celestial beacons to detect the motion of the Earth

    CERN Document Server

    Ruggiero, Matteo Luca; Tartaglia, Angelo

    2010-01-01

    We apply a previously proposed relativistic positioning method based on the use of pulsed signals from sources at infinity, to the reconstruction of the world-line of the Earth in the reference frame of distant pulsars. The method considers the null four-vectors built from the period of the pulses and the direction cosines of the propagation from each source. Starting from a simplified problem (a receiver at rest) we have been able to calibrate our procedure, evidencing the influence of the uncertainty on the arrival times of the pulses as measured by the receiver, and of the numerical treatment of the data. The most relevant parameter turns out to be the accuracy of the clock used by the receiver. Actually the uncertainty used in the simulations combines both the accuracy of the clock and the fluctuations in the sources. The method has then been applied to the case of the Earth, simulating the arrival times of the signals from four pulsars at the location of the Parkes radiotelescope in Australia. A rough ap...

  1. 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.

  2. Cognitive framing in action.

    Science.gov (United States)

    Huhn, John M; Potts, Cory Adam; Rosenbaum, David A

    2016-06-01

    Cognitive framing effects have been widely reported in higher-level decision-making and have been ascribed to rules of thumb for quick thinking. No such demonstrations have been reported for physical action, as far as we know, but they would be expected if cognition for physical action is fundamentally similar to cognition for higher-level decision-making. To test for such effects, we asked participants to reach for a horizontally-oriented pipe to move it from one height to another while turning the pipe 180° to bring one end (the "business end") to a target on the left or right. From a physical perspective, participants could have always rotated the pipe in the same angular direction no matter which end was the business end; a given participant could have always turned the pipe clockwise or counter-clockwise. Instead, our participants turned the business end counter-clockwise for left targets and clockwise for right targets. Thus, the way the identical physical task was framed altered the way it was performed. This finding is consistent with the hypothesis that cognition for physical action is fundamentally similar to cognition for higher-level decision-making. A tantalizing possibility is that higher-level decision heuristics have roots in the control of physical action, a hypothesis that accords with embodied views of cognition.

  3. Semiclassical framed BPS states

    CERN Document Server

    Moore, Gregory W; Bleeken, Dieter Van den

    2015-01-01

    We provide a semiclassical description of framed BPS states in four-dimensional N = 2 super Yang-Mills theories probed by 't Hooft defects, in terms of a supersymmetric quantum mechanics on the moduli space of singular monopoles. Framed BPS states, like their ordinary counterparts in the theory without defects, are associated with the L^2 kernel of certain Dirac operators on moduli space, or equivalently with the L^2 cohomology of related Dolbeault operators. The Dirac/Dolbeault operators depend on two Cartan-valued Higgs vevs. We conjecture a map between these vevs and the Seiberg-Witten special coordinates, consistent with a one-loop analysis and checked in examples. The map incorporates all perturbative and nonperturbative corrections that are relevant for the semiclassical construction of BPS states, over a suitably defined weak coupling regime of the Coulomb branch. We use this map to translate wall crossing formulae and the no exotics theorem to statements about the Dirac/Dolbeault operators. The no exo...

  4. Measuring Angular Rate of Celestial Objects Using the Space Surveillance Telescope

    Science.gov (United States)

    2015-03-01

    the focal length of the SST, 30µm is the effective pixel size, and 36,000km is the approximate distance to geosynchronous orbit. Therefore, the...while objects within space not moving at this rate will appear to move across the focal array from data frame to data frame. As the time between...each frame is known and the position of the detected object can be determined in the focal array, it is possible to measure the angular position and

  5. Frame junction vibration transmission with a modified frame deformation model.

    Science.gov (United States)

    Moore, J A

    1990-12-01

    A previous paper dealt with vibration transmission through junctions of connected frame members where the allowed frame deformations included bending, torsion, and longitudinal motions [J.A. Moore, J. Acoust. Soc. Am. 88, 2766-2776 (1990)]. In helicopter and aircraft structures the skin panels can constitute a high impedance connection along the length of the frames that effectively prohibits in-plane motion at the elevation of the skin panels. This has the effect of coupling in-plane bending and torsional motions within the frame. This paper discusses the transmission behavior through frame junctions that accounts for the in-plane constraint in idealized form by assuming that the attached skin panels completely prohibit inplane motion in the frames. Also, transverse shear deformation is accounted for in describing the relatively deep web frame constructions common in aircraft structures. Longitudinal motion in the frames is not included in the model. Transmission coefficient predictions again show the importance of out-of-plane bending deformation to the transmission of vibratory energy in an aircraft structure. Comparisons are shown with measured vibration transmission data along the framing in the overhead of a helicopter airframe, with good agreement. The frame junction description has been implemented within a general purpose statistical energy analysis (SEA) computer code in modeling the entire airframe structure including skin panels.

  6. 风力发电系统中基于双同步参考坐标变换的锁相环设计与实现%DESIGN AND REALIZATION OF PHASE LOCKED LOOP BASED ON DOUBLE SYNCHRONOUS REFERENCE FRAME IN WIND POWER SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    田桂珍; 王生铁; 林百娟; 王志和

    2011-01-01

    In order to assure grid side converter and STACOM in wind power systems of nmning normally under unbalanced grid voltage, the phase of grid voltage need to be obtained quickly and accurately by phase locked loop systems.Software of phase locked loop based on double synchronous reference frame (DSRF SPLL) was put forward to detect the positive and negative sequence components of unbalanced grid voltages, and eliminate the effect of unbalanced grid voltage on phase detection by double dq transformation and decoupling calculation.The hardware for single chip computer was designed and C language programming of DSRF SPLL algorithm was debugged.The experimental results verified the feasibility and correctness of DSRF SPLL proposed in the paper.%该文提出的基于双同步参考坐标变换的锁相环方法通过双dq变换和解耦计算能够检测出不平衡电网电压中的正序分量和负序分量,从而消除电压不平衡的影响.设计了基于单片机的硬件电路,编制了锁相算法的C语言源程序,实验结果验证了该方法的可行性和正确性.

  7. What's in a frame?

    DEFF Research Database (Denmark)

    Holmgreen, Lise-Lotte

    In the wake of the 2008 financial crisis, many large international banks received heavy criticism for their business conduct, which involved investments in dubious loans and business projects. For Denmark’s largest bank, Danske Bank, the situation was no different; it went from being considered...... from excellent to appalling within a number of months without it being able to benefit from its history of impeccable business conduct as the crisis hit (cf. Coombs 1995). In answering this question, I will argue that organisations are not operating in a social vacuum, but need to consider......; Lakoff 1993, 2003). Thus, in my presentation I will be concerned with the ways metaphor interact with other lexical items in the frames used by the Bank and the press to promote particular problem definitions and moral obligations, in turn assessing why these metaphors may or may not resonate...

  8. IN-FLIGHT ALIGNMENT OF INERTIAL NAVIGATION SYSTEM BY CELESTIAL OBSERVATION TECHNIQUE%基于天文观测技术的惯性导航系统的空中对准

    Institute of Scientific and Technical Information of China (English)

    阿里·捷木思; 房建成

    2005-01-01

    This paper presents an in-flight alignment technique for a strapdown inertial navigation system (SINS) and employs a star pattern recognition procedure for identifying stars sensed by a CCD electrooptical star sensor. Collinearity equations are used to estimate sensor frame star coordinates and the conventional least square differ-ential correction method is used to estimate the unknown orientation angles. A comparison of this attitude with the attitude estimated by the SINS provides axis misalignment angles. Simulations using a Kalman filter are carried out for an SINS and the system employs a local level navigation frame. The space stabilized SINS is discussed in conjunction with the celestial aiding. Based on the observation of the Kalman filter, the estimating and compensating gyro errors, as well as the position and velocity errors caused by the SINS misalignments are calibrated by celestial attitute information.%提出了一种基于CCD星敏感器的捷联惯性导航系统的空中对准方法.应用双线性方程求解被观测星在星敏感器坐标系中的坐标值及传统最小二乘微分校正法求解捷联惯性导航的姿态,该姿态值与捷联惯性导航解算姿态的差值就是惯性导航系统的失准角.作为Kalman滤波器的观测量,计算机仿真结果表明,天文姿态信息有效地校正了陀螺漂移和初始失准角引起的位置和速度误差.

  9. Framing the Game: Examining Frame Choice in Bargaining.

    Science.gov (United States)

    Blount; Larrick

    2000-01-01

    This article introduces the study of frame choice in negotiation. Here, the selection of a procedural frame is treated as a dependent variable-a choice that bargainers make in addition to determining their offers. The empirical focus of the article is on whether, when given a choice between two alternative versions of the ultimatum bargaining game, negotiators choose the description that maximizes their expected payoffs. For example, in one frame-choice task, negotiators assigned to the Player 1 role were asked to select between framing the game as "Player 1 proposes a division and Player 2 accepts or rejects it" or "Player 1 makes a claim from a common pool and Player 2 makes a counterclaim." Past research has shown that the second frame leads to higher expected payoffs for Player 1 than does the first. Across four studies and three established framing effects, it is found that participants consistently fail to select the procedural frames that optimize monetary outcomes. Subsequent analyses suggest that this tendency is due to two factors: (a) nonmonetary motivations, such as fairness and respect, that influence frame-choice preferences and (b) cognitive limitations that inhibit the ability to accurately predict the effect of alternative procedural frames on opponents' responses Copyright 2000 Academic Press.

  10. Is the aether entrained by the motion of celestial bodies? What do the experiments tell us?

    CERN Document Server

    Levy, Joseph

    2012-01-01

    Even though the concept has evolved and if the designation as aether is improperly regarded as outdated, nobody today considers that the vacuum is empty. However, the nature and the properties of the substratum, which permeates the entire universe, remain for the most part unspecified. For example, divergent opinions are put forward by physicists about a possible dragging of the aether by the translational motion of celestial bodies due to gravitation. We show in this text that such a hypothesis is inconsistent with well established experimental data which, on the contrary, lend support to non-entrained aether theory based on Lorentz contraction. A revaluation of the aether drift to which the Earth is subjected is carried out.

  11. 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.

  12. 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...

  13. SAS-2 observations of celestial diffuse gamma radiation above 30 MeV

    Science.gov (United States)

    Thompson, D. J.; Fichtel, C. E.; Kniffen, D. A.; Hartman, R. C.

    1974-01-01

    The small astronomy satellite, SAS-2, used a 32-deck magnetic core digitized spark chamber to study gamma rays with energies above 30 MeV. Data for four regions of the sky away from the galactic plane were analyzed. These regions show a finite, diffuse flux of gamma rays with a steep energy spectrum, and the flux is uniform over all the regions. Represented by a power law, the differential energy spectrum shows an index of 2.5 + or - 0.4. The steep SAS-2 spectrum and the lower energy data are reasonably consistent with a neutral pion gamma-ray spectrum which was red-shifted (such as that proposed by some cosmological theories). It is concluded that the diffuse celestial gamma ray spectrum observed presents the possibility of cosmological studies and possible evidence for a residual cosmic ray density, and supports the galactic superclusters of matter and antimatter remaining from baryon-symmetric big bang.

  14. 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

    In this study, repetitive current controllers operating in either the mixed or stationary frame are proposed for high-precision reference tracking and disturbance rejection of power converters. Both controllers use a proportional-resonant regulator in the stationary frame for regulating...... 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...

  15. Frames of most uniform Hubble flow

    CERN Document Server

    Kraljic, David

    2016-01-01

    It has been observed that the locally measured Hubble parameter converges quickest to the background value and the dipole structure of the velocity field is smallest in the reference frame of the Local Group of galaxies. We study the statistical properties of Lorentz boosts with respect to the Cosmic Microwave Background frame which make the Hubble flow look most uniform around a particular observer. We use a very large N-Body simulation to extract the dependence of the boost velocities on the local environment such as underdensities, overdensities, and bulk flows. We find that the observation is not unexpected if we are located in an underdensity, which is indeed the case for our position in the universe. The amplitude of the measured boost velocity for our location is consistent with the expectation in the standard cosmology.

  16. 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".

  17. 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

  18. Language use depending on news frame and immigrant origin.

    Science.gov (United States)

    Fernández, Itziar; Igartua, Juan-José; Moral, Félix; Palacios, Elena; Acosta, Tania; Muñoz, Dolores

    2013-01-01

    The purpose of this study was to analyze the effect of the media on individuals' specific language use in relation to a news story on immigration: the influence of the news frame and group cue. Abstraction, complexity of language use, and negative affective language were evaluated. The 523 participants were randomly distributed to each of the four experimental conditions: news frame (crime versus economic contribution) by group cue (geographical origin of the immigrants involved: Moroccans versus Latin Americans). Through content analysis of the ideas and reflections that arose after the participants read the different news stories, using the Linguistic Category Model (LCM; Semin & Fiedler, 1991) to measure abstract language and the Linguistic Inquiry and Word Count (LIWC; Pennebaker, Booth, & Francis, 2007) to analyze complex language and negative affective language, it emerged that abstract language and negative affective language were more frequent in the participants assigned to the news frame on crime. Complex language was more commonly used when the news frame referred to the economic contribution of immigrants. Regression analyses showed the mediating role of attitude to immigration in the effects of news frame on negative affective language. The bootstrap method was used to assess the magnitude of the indirect effect. A significant mediator effect was also found through structural equation modeling. Analyses of covariance showed one interaction between news frame and group cue: Among those who read the news story in a frame linking immigration to crime and Moroccan origin, abstract language was more characteristic. The results are discussed from the theoretical perspective of framing.

  19. Reference Revolutions.

    Science.gov (United States)

    Mason, Marilyn Gell

    1998-01-01

    Describes developments in Online Computer Library Center (OCLC) electronic reference services. Presents a background on networked cataloging and the initial implementation of reference services by OCLC. Discusses the introduction of OCLC FirstSearch service, which today offers access to over 65 databases, future developments in integrated…

  20. Pairs of dual periodic frames

    DEFF Research Database (Denmark)

    Christensen, Ole; Goh, Say Song

    2012-01-01

    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...

  1. Framing the patent troll debate.

    Science.gov (United States)

    Risch, Michael

    2014-02-01

    The patent troll debate has reached a fevered pitch in the USA. This editorial seeks to frame the debate by pointing out the lack of clarity in defining patent trolls and their allegedly harmful actions. It then frames the debate by asking currently unanswered questions: Where do troll patents come from? What are the effects of troll assertions? Will policy changes improve the system?

  2. Mercury and frame-dragging in light of the MESSENGER flybys: conflict with general relativity, poor knowledge of the physical properties of the Sun, data reduction artifact, or still insufficient observations?

    CERN Document Server

    Iorio, Lorenzo

    2011-01-01

    The Lense-Thirring precession of the longitude of perihelion of Mercury, as predicted by general relativity by using the value of the Sun's angular momentum S = 190 x 10^39 kg m^2 s^-1 from helioseismology, is -2.0 milliarcseconds per century, computed in a celestial equatorial reference frame. It disagrees at 4-{\\sigma} level with the correction 0.4 +/- 0.6 milliarcseconds per century to the standard Newtonian/Einsteinian precession. It was recently determined in a global fit with the INPOP10a ephemerides to a long planetary data record (1914-2010) including also 3 data points collected in 2008-2009 from the MESSENGER spacecraft. The INPOP10a models did not include the solar gravitomagnetic field at all, so that its signature might have partly been removed in the data reduction process. On the other hand, the Lense-Thirring precession may have been canceled to a certain extent by the competing precession caused by a small mismodeling in the quadrupole mass moment of the Sun, actually modeled, of the order of...

  3. Quotation and Framing

    DEFF Research Database (Denmark)

    Petersen, Nils Holger

    2010-01-01

    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...

  4. Time reference decoupled from tense in agrammatic and fluent aphasia

    NARCIS (Netherlands)

    Bos, Laura; Bastiaanse, Roelien

    2014-01-01

    Background: Reference to an event's time frame can be accomplished through verb inflection. In agrammatic aphasia, a deficit in past time reference has been identified by Bastiaanse and colleagues (2011). In fluent aphasia, specific problems with this time frame (expressed by the past tense) have be

  5. Long-term Dynamical Behavior of Highly Perturbed Natural and Artificial Celestial Bodies

    Science.gov (United States)

    Rosengren, Aaron J.

    This thesis explores the dynamical evolution of celestial bodies, both natural and artificial, which are strongly perturbed by solar radiation pressure---a non-gravitational force that has played an increasingly important role in celestial mechanics since the early 1900s. The particular focus is on the high area-to-mass ratio (HAMR) space debris discovered in near geosynchronous Earth orbit (GEO) through optical observations in 2004, and on micron-sized circumplanetary dust particles in the outer Saturnian system. The formalism developed can also be applied to---and, indeed, was unquestionably influenced by---the orbital motion of spacecraft about small bodies (asteroids and comets). The chief difficulties which arise in getting an accurate understanding of the motion of such bodies in highly perturbed dynamical environments come, in part, from the nonlinearity of the dynamical system, but more so from the inadequacy of the classical approaches and methods. While modern formulations based on numerical integrations can give "precise" solutions for specific initial conditions, these afford little insight into the nature of the problem or the essential dependence of the perturbed motion on the system parameters. The predominant perturbations acting on HAMR objects and circumplanetary dust grains are solar radiation pressure, planetary oblateness, and third-body gravitational interactions induced by the Sun and nearby natural satellites. We developed first-order averaged models, based on the Milankovitch formulation of perturbation theory, which govern the long-term evolution of orbits subject to these perturbing forces. The unexpectedly rich results obtained by the use of this vector formalism are due to certain important circumstances in celestial and quantum mechanics which gave rise to its origin and development. An attempt has been made to trace these historical developments and to put them into the perspective of the present. The averaged equations of motion hold

  6. Framing of task performance strategies: effects on performance in a multiattribute dynamic decision making environment.

    Science.gov (United States)

    Nygren, T E

    1997-09-01

    It is well documented that the way a static choice task is "framed" can dramatically alter choice behavior, often leading to observable preference reversals. This framing effect appears to result from perceived changes in the nature or location of a person's initial reference point, but it is not clear how framing effects might generalize to performance on dynamic decision making tasks that are characterized by high workload, time constraints, risk, or stress. A study was conducted to examine the hypothesis that framing can introduce affective components to the decision making process and can influence, either favorably (positive frame) or adversely (negative frame), the implementation and use of decision making strategies in dynamic high-workload environments. Results indicated that negative frame participants were significantly impaired in developing and employing a simple optimal decision strategy relative to a positive frame group. Discussion focuses on implications of these results for models of dynamic decision making.

  7. Framed School--Frame Factors, Frames and the Dynamics of Social Interaction in School

    Science.gov (United States)

    Persson, Anders

    2015-01-01

    This paper aims to show how the Goffman frame perspective can be used in an analysis of school and education and how it can be combined, in such analysis, with the frame factor perspective. The latter emphasizes factors that are determined outside the teaching process, while the former stresses how actors organize their experiences and define…

  8. Status of GRAIL Gravity Field Determination Using the Celestial Mechanics Approach

    Science.gov (United States)

    Arnold, Daniel; Beutler, Gerhard; Jäggi, Adrian; Bock, Heike; Mervart, Leos; Meyer, Ulrich; Bertone, Stefano

    To determine the gravity field of the Moon, the NASA mission GRAIL (Gravity Recovery And Interior Laboratory) inherits its concept from the Earth orbiting GRACE (Gravity Recovery and Climate Experiment) mission. The use of ultra-precise inter-satellite Ka-band ranging observations enables data acquisition even when the spacecraft are not tracked from the Earth. The data allows for a highly accurate estimation of the lunar gravity field with unprecedented resolution on both sides of the Moon, which is crucial to improve the understanding of its internal structure and thermal evolution. In this presentation we discuss GRAIL-based lunar gravity fields generated with the Celestial Mechanics Approach. Ka-band range-rate (KBRR) observations and position data (GNI1B products) are used to solve for the lunar gravity field parameters in a generalized orbit determination problem. Apart from normalized spherical harmonic coefficients up to degrees n≤ 200, also arc- and satellite-specific parameters, like initial state vectors and pseudo-stochastic pulses, are set up as common parameters for all measurement types. The latter shall compensate for imperfect models of non-gravitational accelerations, e.g., caused by solar radiation pressure. In addition, especially for the data of the primary mission phase, it is essential to estimate time bias parameters for the KBRR observations. We compare our results from the nominal mission phase with the official Level 2 gravity field models first released in October 2013. Our results demonstrate that the lunar gravity field can be recovered with a high quality by adapting the Celestial Mechanics Approach, even when using pre-GRAIL or pre-SELENE gravity field models as a priori fields and when replacing sophisticated models of non-gravitational accelerations by appropriately spaced and constrained pseudo-stochastic pulses. Yet, the usage of preprocessed position data as pseudo observations is not fully satisfying and is potentially

  9. 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.

  10. Mediernes framing af Folketingsvalget 2015

    OpenAIRE

    Jyrkinewsky Mathiesen, Marie; Fruergaard, Oliver; Toft-Nielsen, Nina Kristine; Løvstrup Thejls, Michelle; Abild Patrzarlek, Louise

    2015-01-01

    This project will be centered around the media’s framing of the political election in Denmark 2015. More specifically, we will examine how the public service channel DR1 has presented and framed the two political parties Alternativet and Det Kon-servative Folkeparti. Our examination will have its basis in framing theories as pre-sented by Robert Entman and Dietram A. Scheufele and also the theory of Social Constructivism. Through a deductive analysis, we have tried to answer whether DR1,...

  11. An ontology for tactical behaviors derived from verb frames

    Science.gov (United States)

    Esterline, Albert C., Jr.; BouSaba, Chafic W.

    2008-04-01

    We present an initial ontology for tactical behaviors conducted by unmanned ground vehicles (UGVs). We focus on activities, which are the denotations of verbs, notably 'move' but also 'look (for)' and several others. These take collective subjects, allowing activities to be attributed to units at various hierarchical levels. The semantics of verbs must consider the denotations of their grammatical complements; that is, we must consider entire verb frames. The thematic relations of the noun-phrase complements are critical, but prepositions also play an important role. FrameNet is an online lexical database of frames derived from text corpora. Our other major resource is Levin's classification of verbs according to how changes in their frames affect their meanings. Although natural languages have a large variety of words for aspects of tactical behaviors, there is motivation to get by with as few basic verbs as possible. A variety of meanings can often be associated with a verb by altering its frame, and we can impose co-reference constraints on combinations of frames to generate structures denoting more complex activities. A simple grammar is developed for the verbs of interest. Protege-Frames ontologies include classes that inherit from linguistically inspired classes but capture domain-specific notions.

  12. 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...

  13. Edward Burne-Jones’ The Days of Creation: A Celestial Utopia

    Directory of Open Access Journals (Sweden)

    Liana De Girolami Cheney

    2014-09-01

    Full Text Available Edward Burne-Jones’ cycle of The Days of Creation of 1870-66(Fogg Art Museum, Harvard University Museums, Cambridge, MA was highly praised and elegantly described by Oscar Wilde: “The picture is divided into six compartments, each representing a day in the Creation of the World, under the symbol of an angel holding a crystal globe, within which is shown the work of a day.” This essay examines how Burne-Jones visualized an unusual celestial creation where angels holding magical spheres unveil the divine manifestation for the creation of a terrestrial realm. His The Days of Creation is an aesthetic culmination of the artistic power of invention, imitation and creation of beauty. Burne-Jones borrows the divine concept of world creation to formulate his own artist creation. Selecting God’s week of creation, he empowers a daily angel to manifest the beauty and power of divine creation. Ultimately, Burne-Jones creates a cosmic utopia, a mythical heavenly and natural realm, where angels design a world of beauty to be emulated not only by the artist, but also by most of all by the viewer.

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

    CERN Document Server

    Crouzet, Nicolas; 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; Gouvret, Carole; Fruth, Thomas; Rauer, Heike; Erikson, Anders; Barbieri, Mauro; Aigrain, Suzanne; Pont, Frédéric

    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 function due to rapid ground seeing variations and instrumental effects. The pointing direction is stable within 10 arcseconds on a daily timescale and drifts by only 34 arcseconds in 50 days. A truly continuous photometry of bright stars is possible in June (the noon sky background peaks at a magnitude R=15 arcsec-2 on June 22), but becomes challenging in July (the noon sky background magnitude is R=12.5 arcsec?2 on July 20). The weather conditions are estimated from the number of stars detected in the field. For the 2008...

  15. Spectrum of the Anomalous Microwave Emission in the North Celestial Pole with WMAP 7-Year Data

    Directory of Open Access Journals (Sweden)

    Anna Bonaldi

    2012-01-01

    Full Text Available We estimate the frequency spectrum of the diffuse anomalous microwave emission (AME on the North Celestial Pole (NCP region of the sky with the Correlated Component Analysis (CCA component separation method applied to WMAP 7-yr data. The NCP is a suitable region for this analysis because the AME is weakly contaminated by synchrotron and free-free emission. By modeling the AME component as a peaked spectrum we estimate the peak frequency to be 21.7±0.8 GHz, in agreement with previous analyses which favored νp < 23 GHz. The ability of our method to correctly recover the position of the peak is verified through simulations. We compare the estimated AME spectrum with theoretical spinning dust models to constrain the hydrogen density nH. The best results are obtained with densities around 0.2–0.3 cm−3, typical of warm ionised medium (WIM to warm neutral medium (WNM conditions. The degeneracy with the gas temperature prevents an accurate determination of nH, especially for low hydrogen ionization fractions, where densities of a few cm−3 are also allowed.

  16. 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.

  17. Asymptotic theory of the motion of celestial bodies in the atmosphere

    Science.gov (United States)

    Stulov, V. P.

    2004-04-01

    At a large entry velocity of celestial bodies into the atmosphere, a mass-loss parameter β= σVe2/2 ( σ is the ablation coefficient) is very large. So, for some versions of the 1908 Tunguska event parameters, one has β=5-25. In the case of comet Shoemaker-Levy 9 fragments entry into Jupiter, the parameter β is 75-100. Some stations of European Fireball Network have observed at May, June 1997 two bolides, for which β was estimated as 150 and 40. Therefore, the limiting theory for meteoroid motion in the atmosphere is developed. The solution of meteoric physics equations depends on two (single body) or three parameters (splitting body), and β is among them as argument of some special functions. The asymptotic limit of the solution at β≫1 looks like changing meteoroid mass from entry value to zero at constant velocity. This limit for a single body was compared with observations in May, June 1997 in Czech Republic, and good agreement was achieved. Ultimate models with fragmentation are necessary to understand some real features of large-scale events. So, results of this work show that for large bodies such as Tunguska space body and comet Shoemaker-Levy 9 fragments, we should discuss a motion of gaseous volume after finishing ablation at almost entry velocity. Probably, the big forest fall in 1908 in Siberia and plumes in 1994 on Jupiter are results of such gas jets.

  18. Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Planets and Celestial Calibration Sources

    CERN Document Server

    Weiland, J L; Hill, R S; Wollack, E; Hinshaw, G; Greason, M R; Jarosik, N; Page, L; Bennett, C L; Dunkley, J; Gold, B; Halpern, M; Kogut, A; Komatsu, E; Larson, D; Limon, M; Meyer, S S; Nolta, M R; Smith, K M; Spergel, D N; Tucker, G S; Wright, E L

    2010-01-01

    We present WMAP seven-year observations of bright sources which are often used as calibrators at microwave frequencies. Ten objects are studied in five frequency bands (23 - 94 GHz): the outer planets (Mars, Jupiter, Saturn, Uranus and Neptune) and five fixed celestial sources (Cas A, Tau A, Cyg A, 3C274 and 3C58). The seven-year analysis of Jupiter provides temperatures which are within 1-sigma of the previously published WMAP five-year values, with slightly tighter constraints on variability with orbital phase, and limits (but no detections) on linear polarization. Scaling factors are provided which, when multiplied by the Wright Mars thermal model predictions at 350 micron, reproduce WMAP seasonally averaged observations of Mars within ~2%. An empirical model is described which fits brightness variations of Saturn due to geometrical effects and can be used to predict the WMAP observations to within 3%. Seven-year mean temperatures for Uranus and Neptune are also tabulated. Uncertainties in Uranus temperatu...

  19. Non-parametric PSF estimation from celestial transit solar images using blind deconvolution

    CERN Document Server

    Gonzalez, Adriana; Jacques, Laurent

    2016-01-01

    Context: Characterization of instrumental effects in astronomical imaging is important in order to extract accurate physical information from the observations. Optics are never perfect and the non-ideal path through the telescope is usually represented by the convolution of an ideal image with a Point Spread Function (PSF). Other sources of noise (read-out, Photon) also contaminate the image acquisition process. The problem of estimating both the PSF filter and a denoised image is called blind deconvolution and is ill-posed. Aims: We propose a blind deconvolution scheme that relies on image regularization. Contrarily to most methods presented in the literature, it does not assume a parametric model of the PSF and can thus be applied to any telescope. Methods: Our scheme uses a wavelet analysis image prior model and weak assumptions on the PSF filter's response. We use the observations from a celestial body transit where such object can be assumed to be a black disk. Such constraints limits the interchangeabil...

  20. Initial deep LOFAR observations of Epoch of Reionization windows: I. The North Celestial Pole

    CERN Document Server

    Yatawatta, S; Brentjens, M A; Labropoulos, P; Pandey, V N; Kazemi, S; Zaroubi, S; Koopmans, L V E; Offringa, A R; Jelic, V; Rubi, O Martinez; Veligatla, V; Wijnholds, S J; Brouw, W N; Bernardi, G; Ciardi, B; Daiboo, S; Harker, G; Mellema, G; Schaye, J; Thomas, R; Vedantham, H; Chapman, E; Abdalla, F B; Alexov, A; Anderson, J; Avruch, I M; Batejat, F; Bell, M E; Bell, M R; Bentum, M; Best, P; Bonafede, A; Bregman, J; Breitling, F; van de Brink, R H; Broderick, J W; Bruggen, M; Conway, J; de Gasperin, F; de Geus, E; Duscha, S; Falcke, H; Fallows, R A; Ferrari, C; Frieswijk, W; Garrett, M A; Griessmeier, J M; Gunst, A W; Hassall, T E; Hessels, J W T; Hoeft, M; Iacobelli, M; Juette, E; Karastergiou, A; Kondratiev, V I; Kramer, M; Kuniyoshi, M; Kuper, G; van Leeuwen, J; Maat, P; Mann, G; McKean, J P; Mevius, M; Mol, J D; Munk, H; Nijboer, R; Noordam, J E; Norden, M J; Orru, E; Paas, H; Pandey-Pommier, M; Pizzo, R; Polatidis, A G; Reich, W; Rottgering, H J A; Sluman, J; Smirnov, O; Stappers, B; Tagger, M; Tang, Y; Tasse, C; ter Veen, S; Vermeulen, R; van Weeren, R J; Wise, M; Wucknitz, O; Zarka, P

    2013-01-01

    The aim of the LOFAR Epoch of Reionization (EoR) project is to detect the spectral fluctuations of the redshifted HI 21cm signal. This signal is weaker by several orders of magnitude than the astrophysical foreground signals and hence, in order to achieve this, very long integrations, accurate calibration for stations and ionosphere and reliable foreground removal are essential. One of the prospective observing windows for the LOFAR EoR project will be centered at the North Celestial Pole (NCP). We present results from observations of the NCP window using the LOFAR highband antenna (HBA) array in the frequency range 115 MHz to 163 MHz. The data were obtained in April 2011 during the commissioning phase of LOFAR. We used baselines up to about 30 km. With about 3 nights, of 6 hours each, effective integration we have achieved a noise level of about 100 microJy/PSF in the NCP window. Close to the NCP, the noise level increases to about 180 microJy/PSF, mainly due to additional contamination from unsubtracted nea...

  1. Approximation of the Inverse -Frame Operator

    Indian Academy of Sciences (India)

    M R Abdollahpour; A Najati

    2011-05-01

    In this paper, we introduce the concept of (strong) projection method for -frames which works for all conditional -Riesz frames. We also derive a method for approximation of the inverse -frame operator which is efficient for all -frames. We show how the inverse of -frame operator can be approximated as close as we like using finite-dimensional linear algebra.

  2. Framing as a Theory of Media Effects.

    Science.gov (United States)

    Scheufele, Dietram A.

    1999-01-01

    Systematizes the fragmented approaches to framing in political communication and integrates them into a comprehensive model. Classifies previous approaches to framing research along two dimensions: media frames versus audience frames; and the way frames are operationalized (independent variable or dependent variable). Identifies four key processes…

  3. Kepler-47 Circumbinary Planets obey Quantization of Angular Momentum per Unit Mass predicted by Quantum Celestial Mechanics (QCM

    Directory of Open Access Journals (Sweden)

    Potter F.

    2014-01-01

    Full Text Available The Kepler-47 circumbinary system has three known planets orbiting its binary star barycenter and therefore can provide a precision test of the Quantum Celestial Mechan- ics (QCM prediction of the quantization of angular momentum per unit mass in all gravitationally bound systems. Two of the planets are in the Habitable Zone (HZ, so system stability can be a primary concern. QCM may be a major contributor to the stability of this system.

  4. 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.

  5. Morphogenesis of Kinetic Reciprocal Frames

    DEFF Research Database (Denmark)

    Parigi, Dario; Sassone, Mario

    2011-01-01

    of interactive architecture (IA) started in the sixties of last century from the intersection between architecture and cybernetics. Recent studies were focused on static and kinematic determinacy of Reciprocal Frames, but their potential in the field of kinetic structures is still unexplored. Reciprocal Frames...... 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...... reciprocal frame is to substitute in the intermediate connection the rotational hinges with pin-slot constraints. The second step it to determine the shape of the slot so as that the desired motion are compatible with the given constraints. The morphogenesis procedure is explained, in particular...

  6. 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.

  7. Meta framing and polyphonic structures

    DEFF Research Database (Denmark)

    Pedersen, Karsten

    2015-01-01

    in various ways in BT’s 2012 coverage of a doping case involving Riis. In this article I investigate the way in which BT meta frames itself and its own actions in order to show and underline the seriousness with which BT treats sports journalism. The study is part of a recurring Danish project harvesting...... and mapping the entire news output in one specified week, and draws on insights from framing theory as well as polyphony theory....

  8. Frames and extension problems II

    DEFF Research Database (Denmark)

    Christensen, Ole; Kim, Hong Oh; Kim, Rae Young

    2014-01-01

    This article is a follow-up on the article Frames and Extension Problems I. Here we will go into more recent progress on the topic and also present some open problems.......This article is a follow-up on the article Frames and Extension Problems I. Here we will go into more recent progress on the topic and also present some open problems....

  9. Reduction of Deformations during Welding Metal Wire Mesh with Frames

    Directory of Open Access Journals (Sweden)

    Krawczyk R.

    2016-06-01

    Full Text Available The article presents an issue referring to a reduction of deformation during welding metal wire mesh into the frames. A problem of a possible reduction of deformations was described taking into account characteristics of a construction of a welded element. Technological tests and their results are provided. Technological recommendations relating to the reduction of deformations of the welded element are given.

  10. 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.

  11. Time References in US and UK Astronomical and Navigational Almanacs

    Science.gov (United States)

    2011-01-01

    full text article. 2011 Metrologia 48 S195 (http://iopscience.iop.org/0026-1394/48/4/S10) Download details: IP Address: 138.162.8.58 The article was...ANSI Std Z39-18 IOP PUBLISHING METROLOGIA Metrologia 48 (2011) S195–S199 doi:10.1088/0026-1394/48/4/S10 Time references in US and UK astronomical and...barycentric ephemeris of the celestial body for which the apparent place is being calculated is TDB. Thus, a transformation is required so that S196 Metrologia

  12. The lizard celestial compass detects linearly polarized light in the blue.

    Science.gov (United States)

    Beltrami, Giulia; Parretta, Antonio; Petrucci, Ferruccio; Buttini, Paola; Bertolucci, Cristiano; Foà, Augusto

    2012-09-15

    The present study first examined whether ruin lizards, Podarcis sicula, are able to orientate using plane-polarized light produced by an LCD screen. Ruin lizards were trained and tested indoors, inside a hexagonal Morris water maze positioned under an LCD screen producing white polarized light with a single E-vector, which provided an axial cue. White polarized light did not include wavelengths in the UV. Lizards orientated correctly either when tested with E-vector parallel to the training axis or after 90 deg rotation of the E-vector direction, thus validating the apparatus. Further experiments examined whether there is a preferential region of the light spectrum to perceive the E-vector direction of polarized light. For this purpose, lizards reaching learning criteria under white polarized light were subdivided into four experimental groups. Each group was tested for orientation under a different spectrum of plane-polarized light (red, green, cyan and blue) with equalized photon flux density. Lizards tested under blue polarized light orientated correctly, whereas lizards tested under red polarized light were completely disoriented. Green polarized light was barely discernible by lizards, and thus insufficient for a correct functioning of their compass. When exposed to cyan polarized light, lizard orientation performances were optimal, indistinguishable from lizards detecting blue polarized light. Overall, the present results demonstrate that perception of linear polarization in the blue is necessary - and sufficient - for a proper functioning of the sky polarization compass of ruin lizards. This may be adaptively important, as detection of polarized light in the blue improves functioning of the polarization compass under cloudy skies, i.e. when the alternative celestial compass based on detection of the sun disk is rendered useless because the sun is obscured by clouds.

  13. Non-parametric PSF estimation from celestial transit solar images using blind deconvolution

    Science.gov (United States)

    González, Adriana; Delouille, Véronique; Jacques, Laurent

    2016-01-01

    Context: Characterization of instrumental effects in astronomical imaging is important in order to extract accurate physical information from the observations. The measured image in a real optical instrument is usually represented by the convolution of an ideal image with a Point Spread Function (PSF). Additionally, the image acquisition process is also contaminated by other sources of noise (read-out, photon-counting). The problem of estimating both the PSF and a denoised image is called blind deconvolution and is ill-posed. Aims: We propose a blind deconvolution scheme that relies on image regularization. Contrarily to most methods presented in the literature, our method does not assume a parametric model of the PSF and can thus be applied to any telescope. Methods: Our scheme uses a wavelet analysis prior model on the image and weak assumptions on the PSF. We use observations from a celestial transit, where the occulting body can be assumed to be a black disk. These constraints allow us to retain meaningful solutions for the filter and the image, eliminating trivial, translated, and interchanged solutions. Under an additive Gaussian noise assumption, they also enforce noise canceling and avoid reconstruction artifacts by promoting the whiteness of the residual between the blurred observations and the cleaned data. Results: Our method is applied to synthetic and experimental data. The PSF is estimated for the SECCHI/EUVI instrument using the 2007 Lunar transit, and for SDO/AIA using the 2012 Venus transit. Results show that the proposed non-parametric blind deconvolution method is able to estimate the core of the PSF with a similar quality to parametric methods proposed in the literature. We also show that, if these parametric estimations are incorporated in the acquisition model, the resulting PSF outperforms both the parametric and non-parametric methods.

  14. 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.

  15. Joint analysis of celestial pole offset and free core nutation series

    Science.gov (United States)

    Malkin, Zinovy

    2016-10-01

    Three combined celestial pole offset (CPO) series computed at the Paris Observatory (C04), the United States Naval Observatory (USNO), and the International VLBI Service for Geodesy and Astrometry (IVS), as well as six free core nutation (FCN) models, were compared from different perspectives, such as stochastic and systematic differences, and FCN amplitude and phase variations. The differences between the C04 and IVS CPO series were mostly stochastic, whereas a low-frequency bias at the level of several tens of μ as was found between the C04 and USNO CPO series. The stochastic differences between the C04 and USNO series became considerably smaller when computed at the IVS epochs, which can indicate possible problems with the interpolation of the IVS data at the midnight epochs during the computation of the C04 and USNO series. The comparison of the FCN series showed that the series computed with similar window widths of 1.1-1.2 years were close to one another at a level of 10-20 μ as, whereas the differences between these series and the series computed with a larger window width of 4 and 7 years reached 100 μ as. The dependence of the FCN model on the underlying CPO series was investigated. The RMS differences between the FCN models derived from the C04, USNO, and IVS CPO series were at a level of approximately 15 μ as, which was considerably smaller than the differences among the CPO series. The analysis of the differences between the IVS, C04, and USNO CPO series suggested that the IVS series would be preferable for both precession-nutation and FCN-related studies.

  16. Framing, truth telling and the problem with non-directive counselling.

    Science.gov (United States)

    Kirklin, D

    2007-01-01

    In this paper several reasons as to why framing issues should be of greater interest to both medical ethicists and healthcare professionals are suggested: firstly, framing can help in explaining health behaviours that can, from the medical perspective, appear perverse; secondly, framing provides a way of describing the internal structure of ethical arguments; and thirdly, an understanding of framing issues can help in identifying clinical practices, such as non-directive counselling, which may, inadvertently, be failing to meet their own stated ethical aims. The effect of framing on how individuals interpret information and how healthcare choices are influenced by framing are described. Next, the role of framing in ethical discourse is discussed with specific reference to Judith Jarvis Thomson's philosophical mind experiment about abortion and the violinist. Finally, the implications of this analysis are examined for the practice of non-directive counselling, which aims at communicating information in a neutral, value-free way and thereby protecting patient autonomy.

  17. W-F STRUCTURE: A NEW ALGORITHM ON WIRE-FRAME MODELING

    Institute of Scientific and Technical Information of China (English)

    ZengGang; WangChanglu

    1996-01-01

    This paper advances a new algorithm oriented to geometry modeling(GM) by using frame model. The elemental data structure of frame model is the vertex. This algorithm provides a general and rapid method. By this way,we can link the vertices to construct the elemental frame and need not consider the topological relation among vertices which consist of the concrete entity. Then, we can combine the elemental frames to complete frame modeling by using aided-line method referring to concrete entity. We will discuss two keystones in the paper. Then we give a 3D geometry modeling example based on wire-frame model using the new algorithm.Key words CAD, computer graphics, frame model, modeling system

  18. STRESS ANALYSIS OF BICYCLE FRAME

    Directory of Open Access Journals (Sweden)

    Mr.M.V.Pazare

    2014-06-01

    Full Text Available This paper deals with the stress analysis of bicycle frame by using Finite Element Method. The analysis is carried out in Ansys, The F.E.A. results are compared with theoretical results. In theoretical analysis the frame is treated as truss like structure and the stresses in various members of frame like top tube, down tube, seat tube, chain stay and seat stay are determined, considering various condition like, static start up, steady state paddling, vertical impact, horizontal impact, rear wheel braking. Also Finite Element Analysis is done considering the above conditions. From the analysis it is found that there is a good agreement between analytical and F.E.A. results. Result of all the cases reveals that maximum stress is found in top tube of the bicycle frame as compared to other frame members and is equal to 24.84 MPa which is less than yield strength in tension (i.e.Syt = 290 MPa for the material (aluminum T 6061 selected.

  19. 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.

  20. Cooperation, framing and political attitudes

    DEFF Research Database (Denmark)

    Fosgaard, Toke Reinholt; Hansen, Lars Gårn; Wengström, Erik Roland

    This paper shows that political attitudes are linked to cooperative behavior in an incentivized experiment with a large sample randomly drawn from the Danish population. However, this relationship depends on the way the experiment is framed. In the standard game in which subjects give to a public...... that this difference in the framing effect across political point of views is to some extent explained by differences in beliefs and basic cooperation preferences.......This paper shows that political attitudes are linked to cooperative behavior in an incentivized experiment with a large sample randomly drawn from the Danish population. However, this relationship depends on the way the experiment is framed. In the standard game in which subjects give to a public...

  1. Flexible body dynamics in a local frame with explicitly predicted motion

    DEFF Research Database (Denmark)

    Kawamoto, A.; Krenk, Steen; Suzuki, A.

    2010-01-01

    This paper deals with formulation of dynamics of a moving flexible body in a local frame of reference. In a conventional approach the local frame is normally fixed to the corresponding body and always represents the positions and angles of the body: the positions and angles are represented by Car...

  2. Source Code Generator Based on Dynamic Frames

    Directory of Open Access Journals (Sweden)

    Danijel Radošević

    2011-06-01

    Full Text Available Normal 0 21 false false false HR X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Obična tablica"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} This paper presents the model of source code generator based on dynamic frames. The model is named as the SCT model because if its three basic components: Specification (S, which describes the application characteristics, Configuration (C, which describes the rules for building applications, and Templates (T, which refer to application building blocks. The process of code generation dynamically creates XML frames containing all building elements (S, C ant T until final code is produced. This approach is compared to existing XVCL frames based model for source code generating. The SCT model is described by both XML syntax and the appropriate graphical elements. The SCT model is aimed to build complete applications, not just skeletons. The main advantages of the presented model are its textual and graphic description, a fully configurable generator, and the reduced overhead of the generated source code. The presented SCT model is shown on development of web application example in order to demonstrate its features and justify our design choices.

  3. 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.

  4. 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...

  5. 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...

  6. High-Frame-Rate Oil Film Interferometry

    CERN Document Server

    White, Jonathan C; Chen, John

    2010-01-01

    The fluid dynamics video to which this abstract relates contains visualization of the response of a laminar boundary layer to a sudden puff from a small hole. The boundary layer develops on a flat plate in a wind tunnel; the hole is located at a streamwise Reynolds number of 100,000. The visualization of the boundary layer response is accomplished using interferometry of a transparent, thin film of oil placed on the surface immediately downstream of the hole and with its leading edge perpendicular to the direction of flow. Through lubrication theory, it is understood that the rate of change of the spacing of the interference fringes is proportional to the skin friction at any instant. For reference, a small disk-shaped protrusion of the type often used to trip the boundary layer in wind model tunnel testing is also shown. Three cases with different puff strengths are included. Using a high-speed commercial camera, frame rates in excess of 1000/sec have been recorded; the video shown here was taken at 24 frame...

  7. Framing and misperception in public good experiments

    DEFF Research Database (Denmark)

    Fosgaard, Toke Reinholt; Hansen, Lars Gårn; Wengström, Erik Roland

    2017-01-01

    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......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...

  8. Stability of (p, Y)-Operator Frames

    Institute of Scientific and Technical Information of China (English)

    Zhi Hua GUO; Huai Xin CAO; Jun Cheng YIN

    2011-01-01

    In this paper we study the stability of (p, Y)-operator frames. We firstly discuss the relations between p-Bessel sequences (or p-frames) and (p, Y)-operator Bessel sequences (or (p, Y)-operator frames). Through defining a new union, we prove that adding some elements to a given (p, Y)-operator frame, the resulted sequence will be still a (p, Y)-operator frame. We obtain a necessary and sufficient condition for a sequence of compound operators to be a (p, Y)operator frame. Lastly, we show that (p, Y)-operator frames for X are stable under some small perturbations.

  9. Terrestrial Coordinate Systems and Frames

    Science.gov (United States)

    Boucher, C.; Murdin, P.

    2000-11-01

    A terrestrial reference system (TRS) is a spatial reference system corotating with the Earth in its DIURNAL MOTION in space. In such a system, the positions of points anchored on the Earth's solid surface have coordinates which have only small variations with time, as a result of geophysical effects (tectonic or tidal deformations; see TECTONICS, EARTH'S INTERIOR, TIDES). A terrestrial reference ...

  10. Epistemic Frames for Epistemic Games

    Science.gov (United States)

    Shaffer, David W.

    2006-01-01

    This paper, develops the concept of "epistemic frames" as a mechanism through which students can use experiences in video games, computer games, and other interactive learning environments to help them deal more effectively with situations outside of the original context of learning. Building on ideas of "islands of expertise" [Crowley, K., &…

  11. Wavelet frames and their duals

    DEFF Research Database (Denmark)

    Lemvig, Jakob

    2008-01-01

    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. Gold plating on spectacle frames.

    Science.gov (United States)

    Kenny, I; Mitchell, J W; Walsh, G

    1997-05-01

    An investigation was carried out into the thickness and standard of application of the plating and lacquer coatings applied to three metal spectacle frames. All conform to BS 6625 (1991) for plating thickness, but there was considerable variation in regularity and porosity.

  13. 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.

  14. 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 interpreta

  15. Framing Land-use Dynamics

    NARCIS (Netherlands)

    Verburg, P.H.; Veldkamp, A.; Dijst, M.J.; Schot, P.

    2003-01-01

    Framing land use dynamics was organised as part of the Networks in the Delta research programme of Utrecht which is a LUCC endorsed activity since August 2001. The programme aims at developing a generic theoretical and methodeological framework for understanding and modelling the complex interaction

  16. Fight or flight: Affective news framing effects

    OpenAIRE

    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, I show that issue characteristics and the selected news frame can determine whether and how emotions are elicited. Further, I provide evidence that affective news framing effects can arise as the r...

  17. 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

  18. Gaia, Helios, Selene and Ouranos: the three principal celestial bodies and the sky in the ancient Greek cosmogony

    Science.gov (United States)

    Theodossiou, Efstratios; Manimanis, Vassilios N.; Dimitrijević, Milan S.; Mantarakis, Petros

    In this article we consider the role of the three principal celestial bodies, the Earth (Gaia), the Sun (Helios) and the Moon (Selene), as well as the Sky (Ouranos) in the ancient Greek cosmogony. This is done by the analysis of antique Greek texts like Orphic Hymns and the literary remains of the writers and philosophers like Aeschylus, (Pseudo) Apollodorus, Apollonius Rhodius, Aristotle, Euripides, Hesiod, Homer, Hyginus, Nonnus, Pausanias, Pindar and Sophocles, as well as by the analysis of texts of Roman writers like Cicero, Ovid and Pliny.

  19. Quantum and Post-Newtonian Effects in the Anomalistic Period and the Mean Motion of Celestial Bodies

    CERN Document Server

    Haranas, Ioannis; Gkigkitzis, Ioannis; Kotsireas, Ilias

    2015-01-01

    We study the motion of a secondary celestial body under the influence of the corrected gravitational force of a primary. We study the effect of quantum and relativistic corrections to the gravitational potential of a primary body acting on the orbiting body. More specifically, two equations are derived to approximate the perigee/perihelion/periastron time rate of change and its total variation over one revolution (i.e., the difference between the anomalistic period and the Keplerian period) under the influence of the quantum as well as post- Newtonian accelerations. Numerical results have been obtained for the artificial Earth satellite Molnya, Mercury, and, finally, the for the HW Vir c, planetary companion.

  20. Method and System for Gamma-Ray Localization Induced Spacecraft Navigation Using Celestial Gamma-Ray Sources

    Science.gov (United States)

    Sheikh, Suneel I. (Inventor); Hisamoto, Chuck (Inventor); Arzoumanian, Zaven (Inventor)

    2015-01-01

    A method and system for spacecraft navigation using distant celestial gamma-ray bursts which offer detectable, bright, high-energy events that provide well-defined characteristics conducive to accurate time-alignment among spatially separated spacecraft. Utilizing assemblages of photons from distant gamma-ray bursts, relative range between two spacecraft can be accurately computed along the direction to each burst's source based upon the difference in arrival time of the burst emission at each spacecraft's location. Correlation methods used to time-align the high-energy burst profiles are provided. The spacecraft navigation may be carried out autonomously or in a central control mode of operation.

  1. 27.3-day and Average 13.6-day Periodic Oscillations in the Earth's Rotation Rate and Atmospheric Pressure Fields Due to Celestial Gravitation Forcing

    Institute of Scientific and Technical Information of China (English)

    LI Guoqing; ZONG Haifeng; ZHANG Qingyun

    2011-01-01

    Variation in length of day of the Earth (LOD equivalent to the Earth's rotation rate) versus change in atmospheric geopotential height fields and astronomical parameters were analyzed for the years 1962-2006.This revealed that there is a 27.3-day and an average 13.6-day periodic oscillation in LOD and atmospheric pressure fields following lunar revolution around the Earth. Accompanying the alternating change in celestial gravitation forcing on the Earth and its atmosphere, the Earth's LOD changes from minimum to maximum,then to minimum. and the atmospheric geopotential height fields in the tropics oscillate from low to high,then to low. The 27.3-day and average 13.6-day periodic atmospheric oscillation in the tropics is proposed to be a type of strong atmospheric tide, excited by celestial gravitation forcing. A formula for a Tidal Index was derived to estimate the strength of the celestial gravitation forcing, and a high degree of correlation was found between the Tidal Index determined by astronomical parameters, LOD, and atmospheric geopotential height. The reason for the atmospheric tide is periodic departure of the lunar orbit from the celestial equator during lunar revolution around the Earth. The alternating asymmetric change in celestial gravitation forcing on the Earth and its atmosphere produces a "modulation" to the change in the Earth's LOD and atmospheric pressure fields.

  2. The missing link: audience frames in the process model of framing effects

    NARCIS (Netherlands)

    van Drunen, A.S.; Vliegenthart, R.; Boomgaarden, H.G.; de Vreese, C.H.

    2011-01-01

    The process model of framing effects proposes that media frames affect public opinion via audience frames. However, there is a lack of research examining these audience frames. In this investigation we define and subsequently develop an empirical measurement of audience frames, which is applied to t

  3. Ultra-fast framing camera tube

    Science.gov (United States)

    Kalibjian, Ralph

    1981-01-01

    An electronic framing camera tube features focal plane image dissection and synchronized restoration of the dissected electron line images to form two-dimensional framed images. Ultra-fast framing is performed by first streaking a two-dimensional electron image across a narrow slit, thereby dissecting the two-dimensional electron image into sequential electron line images. The dissected electron line images are then restored into a framed image by a restorer deflector operated synchronously with the dissector deflector. The number of framed images on the tube's viewing screen is equal to the number of dissecting slits in the tube. The distinguishing features of this ultra-fast framing camera tube are the focal plane dissecting slits, and the synchronously-operated restorer deflector which restores the dissected electron line images into a two-dimensional framed image. The framing camera tube can produce image frames having high spatial resolution of optical events in the sub-100 picosecond range.

  4. Sparsity and spectral properties of dual frames

    CERN Document Server

    Krahmer, Felix; Lemvig, Jakob

    2012-01-01

    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 expression for the exact sparsity level of the sparsest dual for any given finite frame using a generalized notion of spark. We then study the spectral properties of dual frames in terms of singular values of the synthesis operator. We provide a complete characterization for which spectral patterns of dual frames are possible for a fixed frame. For many cases, we provide simple explicit constructions for dual frames with a given spectrum, in particular, if the constraint on the dual is that it be tight.

  5. 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.

  6. Developing the Framed Standard Model

    CERN Document Server

    Baker, Michael J; Chan, H M; Tsou, S T

    2011-01-01

    The framed standard model (FSM) suggested earlier, which incorporates the Higgs field and 3 fermion generations as part of the framed gauge theory structure, is here developed further to show that it gives both quarks and leptons hierarchical masses and mixing matrices akin to what is experimentally observed. Among its many distinguishing features which lead to the above results are (i) the vacuum is degenerate under a global $su(3)$ symmetry which plays the role of fermion generations, (ii) the fermion mass matrix is "universal", rank-one and rotates (changes its orientation in generation space) with changing scale $\\mu$, (iii) the metric in generation space is scale-dependent too, and in general non-flat, (iv) the theta-angle term in the QCD action of topological origin gets transformed into the CP-violating phase of the CKM matrix for quarks, thus offering at the same time a solution to the strong CP problem.

  7. Classifying tight Weyl-Heisenberg frames

    DEFF Research Database (Denmark)

    Cazsazza, P.; Janssen, A. J. E. M.; Christensen, Ole

    1999-01-01

    A Weyl-Heisenberg frame for L^2(R) is a frame consisting of translates and modulates of a fixed function. In this paper we give necessary and sufficient conditions for this family to form a tight WH-frame. This allows us to write down explicitly all functions g for which all translates and modula......A Weyl-Heisenberg frame for L^2(R) is a frame consisting of translates and modulates of a fixed function. In this paper we give necessary and sufficient conditions for this family to form a tight WH-frame. This allows us to write down explicitly all functions g for which all translates...

  8. Perturbation of Wavelet and Gabor Frames

    Institute of Scientific and Technical Information of China (English)

    Ivana Carrizo; Sergio Favier

    2003-01-01

    In this work two aspects of theory of frames are presented: a side necessary condition on irregular wavelet frames is obtained, another perturbation of wavelet and Gabor frames is considered. Specifically,we present the results obtained on frame stability when one disturbs the mother of wavelet frame, or the parameter of dilatation, and in Gabor frames when the generating function or the parameter of translation are perturbed. In all cases we work without demanding compactness of the support, neither on the generating function, nor on its Fourier transform.

  9. Orthogonal Multiwavelet Frames in L2Rd

    Directory of Open Access Journals (Sweden)

    Liu Zhanwei

    2012-01-01

    Full Text Available We characterize the orthogonal frames and orthogonal multiwavelet frames in L2Rd with matrix dilations of the form (Df(x=detAf(Ax, where A is an arbitrary expanding d×d matrix with integer coefficients. Firstly, through two arbitrarily multiwavelet frames, we give a simple construction of a pair of orthogonal multiwavelet frames. Then, by using the unitary extension principle, we present an algorithm for the construction of arbitrarily many orthogonal multiwavelet tight frames. Finally, we give a general construction algorithm for orthogonal multiwavelet tight frames from a scaling function.

  10. Actual Problems in Celestial Mechanics and Dynamical Astronomy, International Conference Cluj/Napoca, Romania, May 25-27, 2006

    Science.gov (United States)

    Érdi, B.; Szenkovits, F.

    2007-05-01

    In 25--27 May 2006 an International Conference on Actual Problems in Celestial Mechanics and Dynamical Astronomy was organized at Cluj-Napoca. The Faculty of Mathematics and Computer Science of the Babeş-Bolyai University, the host of this conference, organized this scientific meeting in collaboration with the Loránd Eötvös University (Budapest, Hungary), Sapientia University (Miercuria Ciuc, Romania), Astronomical Institute of the Romanian Academy (Bucharest, Romania) and Institute for Space Science (Bucharest, Romania). The main topics covered by the meeting were: - Solar-System dynamics, stability, resonances, chaos; - Dynamics of populations in the Solar System: NEAs, MBAs, Centaurs, KBOs, TNOs: observations, orbits, theoretical models; - Galactic and extragalactic dynamics; - Problems, models, methods and techniques in contemporary celestial mechanics and dynamical astronomy. The conference was structured into seven sessions of oral presentations, a poster session and a round table discussion. Each of the seven main sessions began with an invited lecture. These lectures reviewed the following fields: the Sitnikov problem (R. Dvorak, Austria); the age of the asteroid families (Z. Knezevic, Serbia and Montenegro); stability of exoplanetary systems (B. Érdi, Hungary); Saari's conjecture (Diacu, Canada); integrability from direct and inverse standpoints (G. Bozis, Greece); stability of exact solutions in restricted many-body problems (E. Grebenicov, Russia); actual Romanian research in post-Newtonian dynamics (V. Mioc, Romania). Beside the invited lectures, the 21 oral presentations covered the most various domains of celestial mechanics and dynamical astronomy. Chaotic behaviour was a premier topic. It was approached and studied by analytical, geometrical and numerical methods in many astronomical problems: the restricted three-body problem (with examples in the Solar System), the Gylden's model and its generalizations, capture domain, resonances, etc

  11. 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...

  12. 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...... for finite subfamilies is crucial. (C) 2001 Elsevier Science Inc. All rights reserved....

  13. TWO CONDITIONS FOR NONUNIFORM GABOR FRAMES

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A necessary condition is given for general nonuniform Gabor frames, which generalizes Benedetto and Walnut's theorem. A sufficient and necessary condition for a class of nonuniform Gabor frames is proved.

  14. Analisis Framing dalam Riset Public Relations

    OpenAIRE

    NARAYANA MAHENDRA PRASTYA

    2016-01-01

    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 cons...

  15. A Class of Bidimensional FMRA Wavelet Frames

    Institute of Scientific and Technical Information of China (English)

    Yun Zhang LI

    2006-01-01

    This paper addresses the construction of wavelet frame from a frame multiresolution analysis (FMRA) associated with a dilation matrix of determinant ±2. The dilation matrices of determinant ±2 can be classified as six classes according to integral similarity. In this paper, for four classes of them, the construction of wavelet frame from an FMRA is obtained, and, as examples, Shannon type wavelet frames are constructed, which have an independent value for their optimality in some sense.

  16. 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.

  17. 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,

  18. Influence of framing on medical decision making

    OpenAIRE

    Feng, Jun; Gong, Jingjing; Huang, Yonghua; Wei, Yazhou; Zhang, Weiwei; Zhang, Yan

    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.

  19. Getting real: the duration of framing effects

    NARCIS (Netherlands)

    Lecheler, S.; de Vreese, C.H.

    2011-01-01

    A growing number of studies test the effects of news framing on citizens’ understanding of politics. By employing experimental designs, these studies report significant effects for a multitude of issues and frames. However, what happens to the framing effect after initial exposure? Based on a ‘‘clas

  20. A Framed Temporal Logic Programming Language

    Institute of Scientific and Technical Information of China (English)

    Zhen-Hua Duan; Maciej Koutny

    2004-01-01

    We discuss the projection temporal logic (PTL), based on a primitive projection operator, prj. A framing technique is also presented, using which a synchronization operator, await, is defined within the underlying logic. A framed temporal logic programming language (FTLL) is presented. To illustrate how to use both the language and framing technique, some examples are given.

  1. 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...

  2. Irregular wavelet frames on L2(Rn)

    Institute of Scientific and Technical Information of China (English)

    YANG Deyun; ZHOU Xingwei

    2005-01-01

    In this paper, we present the conditions on dilation parameter {sj }j that ensure a discrete irregular wavelet system {Snj/2ψ(sj·-bk)}j∈(Z),k∈(Z)n to be a frame on L2(Rn),and for the wavelet frame we consider the perturbations of translation parameter b and frame function ψ respectively.

  3. 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...

  4. 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...

  5. 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...

  6. Quantum games in noninertial frame

    CERN Document Server

    Khan, Salman

    2011-01-01

    We study the influence of Unruh effect on quantum non-zero sum games. In particular, we investigate the quantum prisoners' dilemma under different conditions and show that the acceleration of the noninertial frames disturbs the symmetry of the game. It is shown that under some particular situations, the classical strategy C (cooperation) becomes the dominant strategy. Our investigation shows that any quantum strategy does no better for any player against the classical strategies. The miracle move of Eisert et al [5] is no more a superior move. We show that the dilemma like situation under every condition of the game is resolved.

  7. Gauge fields in accelerated frames

    CERN Document Server

    Lenz, F

    2008-01-01

    Quantized fields in accelerated frames (Rindler spaces) with emphasis on gauge fields are investigated. Important properties of the dynamics in Rindler spaces are shown to follow from the scale invariance of the corresponding Hamiltonians. Origin and consequences of this extraordinary property of Hamiltonians in Rindler spaces are elucidated. Characteristics of the Unruh radiation, the appearance of a photon condensate and the interaction energy of vector and scalar static charges are discussed and implications for Yang-Mills theories and QCD in Rindler spaces are indicated.

  8. Changes in rod and frame test scores recorded in schoolchildren during development--a longitudinal study.

    Directory of Open Access Journals (Sweden)

    Jeff Bagust

    Full Text Available The Rod and Frame Test has been used to assess the degree to which subjects rely on the visual frame of reference to perceive vertical (visual field dependence-independence perceptual style. Early investigations found children exhibited a wide range of alignment errors, which reduced as they matured. These studies used a mechanical Rod and Frame system, and presented only mean values of grouped data. The current study also considered changes in individual performance. Changes in rod alignment accuracy in 419 school children were measured using a computer-based Rod and Frame test. Each child was tested at school Grade 2 and retested in Grades 4 and 6. The results confirmed that children displayed a wide range of alignment errors, which decreased with age but did not reach the expected adult values. Although most children showed a decrease in frame dependency over the 4 years of the study, almost 20% had increased alignment errors suggesting that they were becoming more frame-dependent. Plots of individual variation (SD against mean error allowed the sample to be divided into 4 groups; the majority with small errors and SDs; a group with small SDs, but alignments clustering around the frame angle of 18°; a group showing large errors in the opposite direction to the frame tilt; and a small number with large SDs whose alignment appeared to be random. The errors in the last 3 groups could largely be explained by alignment of the rod to different aspects of the frame. At corresponding ages females exhibited larger alignment errors than males although this did not reach statistical significance. This study confirms that children rely more heavily on the visual frame of reference for processing spatial orientation cues. Most become less frame-dependent as they mature, but there are considerable individual differences.

  9. A Formal Description of Problem Frames

    Directory of Open Access Journals (Sweden)

    Souleymane KOUSSOUBE

    2014-03-01

    Full Text Available 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 ABOX. The Description Logics inference tools can then be used to decompose multi frame problems or to fix a particular problem into a Problem Frame.

  10. Manufacturing of neutron reflector frame for JMTR

    OpenAIRE

    2010-01-01

    Beryllium has been used as the neutron reflector in the Japan Materials Testing Reactor (JMTR). A beryllium frame is arranged in the JMTR core and the frame consists of 3 sections (North, East and West). Each section has 7 stories of the beryllium blocks. Each block is connected by the aluminum joints. The capsule or the beryllium plug is located in the inside of the beryllium frame. The first criticality achieved in 1968 and the frame has been replaced 6 times and now the 7th frame is being ...

  11. 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

  12. The Relations between Discrete Frames and Continuous Frames with Respect to (N, µ)

    Institute of Scientific and Technical Information of China (English)

    LIU Chun-tai

    2013-01-01

    The discrete frame and the continuous frame in a Hilbert space are discussed. By the tool excess of a sequence, a sufficient and necessary condition is presented under which a discrete frame is equivalent to a continuous frame with respect to the whole natural numbers with a positive Borel measure. And some examples are given to illuminate the condition.

  13. Frame ambiguity in policy controversies: critical frame analysis of migrant integration policies in Antwerp and Rotterdam

    NARCIS (Netherlands)

    R. Dekker (Rianne)

    2016-01-01

    textabstractPolicy frames are understood as the outcome of a policy process in which multiple frames are contesting, but where one frame prevails and characterizes policies. Policy frames are therefore perceived and studied as coherent interpretations of a policy issue containing a problem definitio

  14. Message framing in social networking sites.

    Science.gov (United States)

    Kao, Danny Tengti; Chuang, Shih-Chieh; Wang, Sui-Min; Zhang, Lei

    2013-10-01

    Online social networking sites represent significant new opportunities for Internet advertisers. However, results based on the real world cannot be generalized to all virtual worlds. In this research, the moderating effects of need for cognition (NFC) and knowledge were applied to examine the impact of message framing on attitudes toward social networking sites. A total of 216 undergraduates participated in the study. Results reveal that for social networking sites, while high-NFC individuals form more favorable attitudes toward negatively framed messages than positively framed messages, low-NFC individuals form more favorable attitudes toward positively framed messages than negatively framed messages. In addition, low-knowledge individuals demonstrate more favorable attitudes toward negatively framed messages than positively framed messages; however, the framing effect does not differentially affect the attitudes of high-knowledge individuals. Furthermore, the framing effect does not differentially affect the attitudes of high-NFC individuals with high knowledge. In contrast, low-NFC individuals with low knowledge hold more favorable attitudes toward positively framed messages than negatively framed messages.

  15. 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.

  16. Zero initial partial derivatives of satellite orbits with respect to force parameters violate the physics of motion of celestial bodies

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Satellite orbits have been routinely used to produce models of the Earth’s gravity field. In connection with such productions, the partial derivatives of a satellite orbit with respect to the force parameters to be determined, namely, the unknown harmonic coefficients of the gravitational model, have been first computed by setting the initial values of partial derivatives to zero. In this note, we first design some simple mathematical examples to show that setting the initial values of partial derivatives to zero is generally erroneous mathematically. We then prove that it is prohibited physically. In other words, set-ting the initial values of partial derivatives to zero violates the physics of motion of celestial bodies.

  17. Zero initial partial derivatives of satellite orbits with respect to force parameters violate the physics of motion of celestial bodies

    Institute of Scientific and Technical Information of China (English)

    XU PeiLiang

    2009-01-01

    Satellite orbits have been routinely used to produce models of the Earth's gravity field. In connection with such productions, the partial derivatives of a satellite orbit with respect to the force parameters to be determined, namely, the unknown harmonic coefficients of the gravitational model, have been first computed by setting the initial values of partial derivatives to zero. In this note, we first design some simple mathematical examples to show that setting the initial values of partial derivatives to zero is generally erroneous mathematically. We then prove that it is prohibited physically. In other words, set-ting the initial values of partial derivatives to zero violates the physics of motion of celestial bodies.

  18. 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.

  19. 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.

  20. "Think" versus "feel" framing effects in persuasion.

    Science.gov (United States)

    Mayer, Nicole D; Tormala, Zakary L

    2010-04-01

    Three studies explored think ("I think . . . ") versus feel ("I feel . . . ") message framing effects on persuasion.The authors propose a matching hypothesis, suggesting that think framing will be more persuasive when the target attitude or message recipient is cognitively oriented, whereas feel framing will be more persuasive when the target attitude or message recipient is affectively oriented. Study 1 presented cognitively and affectively oriented individuals with a think- or feel-framed message. Study 2 primed cognitive or affective orientation and then presented a think- or feel-framed message. Study 3 presented male and female participants with an advertisement containing think- or feel-framed arguments. Results indicated that think (feel) framing was more persuasive when the target attitude or recipient was cognitively (affectively) oriented. Moreover, Study 2 demonstrated that this matching effect was mediated by processing fluency. Theoretical and practical implications are discussed.