Integration of Reference Frames Using VLBI

Science.gov (United States)

Ma, Chopo; Smith, David E. (Technical Monitor)

2001-01-01

Very Long Baseline Interferometry (VLBI) has the unique potential to integrate the terrestrial and celestial reference frames through simultaneous estimation of positions and velocities of approx. 40 active VLBI stations and a similar number of stations/sites with sufficient historical data, the position and position stability of approx. 150 well-observed extragalactic radio sources and another approx. 500 sources distributed fairly uniformly on the sky, and the time series of the five parameters that specify the relative orientation of the two frames. The full realization of this potential is limited by a number of factors including the temporal and spatial distribution of the stations, uneven distribution of observations over the sources and the sky, variations in source structure, modeling of the solid/fluid Earth and troposphere, logistical restrictions on the daily observing network size, and differing strategies for optimizing analysis for TRF, for CRF and for EOP. The current status of separately optimized and integrated VLBI analysis will be discussed.

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

Science.gov (United States)

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

2017-12-01

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

Changing quantum reference frames

OpenAIRE

Palmer, Matthew C.; Girelli, Florian; Bartlett, Stephen D.

2013-01-01

We consider the process of changing reference frames in the case where the reference frames are quantum systems. We find that, as part of this process, decoherence is necessarily induced on any quantum system described relative to these frames. We explore this process with examples involving reference frames for phase and orientation. Quantifying the effect of changing quantum reference frames serves as a first step in developing a relativity principle for theories in which all objects includ...

Optimal primitive reference frames

International Nuclear Information System (INIS)

Jennings, David

2011-01-01

We consider the smallest possible directional reference frames allowed and determine the best one can ever do in preserving quantum information in various scenarios. We find that for the preservation of a single spin state, two orthogonal spins are optimal primitive reference frames; and in a product state, they do approximately 22% as well as an infinite-sized classical frame. By adding a small amount of entanglement to the reference frame, this can be raised to 2(2/3) 5 =26%. Under the different criterion of entanglement preservation, a very similar optimal reference frame is found; however, this time it is for spins aligned at an optimal angle of 87 deg. In this case 24% of the negativity is preserved. The classical limit is considered numerically, and indicates under the criterion of entanglement preservation, that 90 deg. is selected out nonmonotonically, with a peak optimal angle of 96.5 deg. for L=3 spins.

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

Inertial reference frames and gravitational forces

International Nuclear Information System (INIS)

Santavy, I.

1981-01-01

The connection between different definitions of inertial, i.e. fundamental, reference frames and the corresponding characterisation of gravitational fields by gravitational forces are considered from the point of view of their possible interpretation in university introductory courses. The introduction of a special class of reference frames, denoted 'mixed reference frames' is proposed and discussed. (author)

Physics of Non-Inertial Reference Frames

International Nuclear Information System (INIS)

Kamalov, Timur F.

2010-01-01

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

``Frames of Reference'' revisited

Science.gov (United States)

Steyn-Ross, Alistair; Ivey, Donald G.

1992-12-01

The PSSC teaching film, ``Frames of Reference,'' was made in 1960, and was one of the first audio-visual attempts at showing how your physical ``point of view,'' or frame of reference, necessarily alters both your perceptions and your observations of motion. The gentle humor and original demonstrations made a lasting impact on many audiences, and with its recent re-release as part of the AAPT Cinema Classics videodisc it is timely that we should review both the message and the methods of the film. An annotated script and photographs from the film are presented, followed by extension material on rotating frames which teachers may find appropriate for use in their classrooms: constructions, demonstrations, an example, and theory.

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

Quantum frames of reference

International Nuclear Information System (INIS)

Kaufherr, T.

1981-01-01

The idea that only relative variables have physical meaning came to be known as Mach's principle. Carrying over this idea to quantum theory, has led to the consideration of finite mass, macroscopic reference frames, relative to which all physical quantities are measured. During the process of measurement, a finite mass observer receives a kickback, and this reaction of the measuring device is not negligible in quantum theory because of the quantization of the action. Hence, the observer himself has to be included in the system that is being considered. Using this as the starting point, a number of thought experiments involving finite mass observers is discussed which have quantum uncertainties in their time or in their position. These thought experiments serve to elucidate in a qualitative way some of the difficulties involved, as well as pointing out a direction to take in seeking solutions to them. When the discussion is extended to include more than one observer, the question of the covariance of the theory immediately arises. Because none of the frames of reference should be preferred, the theory should be covariant. This demand expresses an equivalence principle which here is extended to include reference frames which are in quantum uncertainties relative to each other. Formulating the problem in terms of canonical variables, the ensueing free Hamiltonian contains vector and scalar potentials which represent the kick that the reference frame receives during measurement. These are essentially gravitational type potentials, resulting, as it were, from the extension of the equivalence principle into the quantum domain

Are all spatial reference frames egocentric? Reinterpreting evidence for allocentric, object-centered, or world-centered reference frames

Directory of Open Access Journals (Sweden)

Flavia eFilimon

2015-12-01

Full Text Available The use and neural representation of egocentric spatial reference frames is well documented. In contrast, whether the brain represents spatial relationships between objects in allocentric, object-centered, or world-centered coordinates is debated. Here, I review behavioral, neuropsychological, neurophysiological (neuronal recording, and neuroimaging evidence for and against allocentric, object-centered, or world-centered spatial reference frames. Based on theoretical considerations, simulations, and empirical findings from spatial navigation, spatial judgments, and goal-directed movements, I suggest that all spatial representations may in fact be dependent on egocentric reference frames.

Quantum mechanics with respect to different reference frames

International Nuclear Information System (INIS)

Mangiarotti, L.; Sardanashvily, G.

2007-01-01

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

Transformations between inertial and linearly accelerated frames of reference

International Nuclear Information System (INIS)

Ashworth, D.G.

1983-01-01

Transformation equations between inertial and linearly accelerated frames of reference are derived and these transformation equations are shown to be compatible, where applicable, with those of special relativity. The physical nature of an accelerated frame of reference is unambiguously defined by means of an equation which relates the velocity of all points within the accelerated frame of reference to measurements made in an inertial frame of reference. (author)

Are All Spatial Reference Frames Egocentric? Reinterpreting Evidence for Allocentric, Object-Centered, or World-Centered Reference Frames

OpenAIRE

Filimon, Flavia

2015-01-01

The use and neural representation of egocentric spatial reference frames is well-documented. In contrast, whether the brain represents spatial relationships between objects in allocentric, object-centered, or world-centered coordinates is debated. Here, I review behavioral, neuropsychological, neurophysiological (neuronal recording), and neuroimaging evidence for and against allocentric, object-centered, or world-centered spatial reference frames. Based on theoretical considerations, simulati...

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

International Nuclear Information System (INIS)

Xie, Y.; Kopeikon, S.

2010-01-01

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

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

International Nuclear Information System (INIS)

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

2009-01-01

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

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

Science.gov (United States)

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

2017-12-01

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

PHOTOMETRIC OBSERVATIONS OF SELECTED, OPTICALLY BRIGHT QUASARS FOR SPACE INTERFEROMETRY MISSION AND OTHER FUTURE CELESTIAL REFERENCE FRAMES

International Nuclear Information System (INIS)

Ojha, Roopesh; Zacharias, Norbert; Hennessy, Gregory S.; Gaume, Ralph A.; Johnston, Kenneth J.

2009-01-01

Photometric observations of 235 extragalactic objects that are potential targets for the Space Interferometry Mission (SIM) are presented. Mean B, V, R, I magnitudes at the 5% level are obtained at 1-4 epochs between 2005 and 2007 using the 1 m telescopes at Cerro Tololo Inter-American Observatory and the Naval Observatory Flagstaff Station. Of the 134 sources that have V magnitudes in the Veron and Veron-Cetty catalog, a difference of over 1.0 mag is found for the observed-catalog magnitudes for about 36% of the common sources, and 10 sources show over 3 mag difference. Our first set of observations presented here form the basis of a long-term photometric variability study of the selected reference frame sources to assist in mission target selection and to support QSO multicolor photometric variability studies in general.

Balinese Frame of Reference

Directory of Open Access Journals (Sweden)

I Nyoman Aryawibawa

2016-04-01

Full Text Available Abstract: Balinese Frame of Reference. Wassmann and Dasen (1998 did a study on the acquisition of Balinese frames of reference. They pointed out that, in addition to the dominant use of absolute system, the use of relative system was also observed. This article aims at verifying Wassmann and Dasen’ study. Employing monolingual Balinese speakers and using linguistic and non-linguistic tasks, Aryawibawa (2010, 2012, 2015 showed that Balinese subjects used an absolute system dominantly in responding the two tasks, e.g. The man is north/south/east/west of the car. Unlike Wassmann and Dasen’s results, no relative system was used by the subjects in solving the tasks. Instead of the relative system, an intrinsic system was also observed in this study, even though it was unfrequent. The article concludes that the absolute system was dominantly employed by Balinese speakers in describing spatial relations in Balinese. The use of the system seems to affect their cognitive functions.

Quantum reference frames and their applications to thermodynamics.

Science.gov (United States)

Popescu, Sandu; Sainz, Ana Belén; Short, Anthony J; Winter, Andreas

2018-07-13

We construct a quantum reference frame, which can be used to approximately implement arbitrary unitary transformations on a system in the presence of any number of extensive conserved quantities, by absorbing any back action provided by the conservation laws. Thus, the reference frame at the same time acts as a battery for the conserved quantities. Our construction features a physically intuitive, clear and implementation-friendly realization. Indeed, the reference system is composed of the same types of subsystems as the original system and is finite for any desired accuracy. In addition, the interaction with the reference frame can be broken down into two-body terms coupling the system to one of the reference frame subsystems at a time. We apply this construction to quantum thermodynamic set-ups with multiple, possibly non-commuting conserved quantities, which allows for the definition of explicit batteries in such cases.This article is part of a discussion meeting issue 'Foundations of quantum mechanics and their impact on contemporary society'. © 2018 The Author(s).

Mercury's Reference Frames After the MESSENGER Mission

Science.gov (United States)

Stark, A.; Oberst, J.; Preusker, F.; Burmeister, S.; Steinbrügge, G.; Hussmann, H.

2018-05-01

We provide an overview of Mercury's reference frames based on MESSENGER observations. We discuss the dynamical, the principal-axes, the ellipsoid, as well as the cartographic frame, which was adopted for MESSENGER data products.

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…

Quantum communication, reference frames, and gauge theory

International Nuclear Information System (INIS)

Enk, S. J. van

2006-01-01

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

Quantum bit commitment with misaligned reference frames

International Nuclear Information System (INIS)

Harrow, Aram; Oliveira, Roberto; Terhal, Barbara M.

2006-01-01

Suppose that Alice and Bob define their coordinate axes differently, and the change of reference frame between them is given by a probability distribution μ over SO(3). We show that this uncertainty of reference frame is of no use for bit commitment when μ is uniformly distributed over a (sub)group of SO(3), but other choices of μ can give rise to a partially or even arbitrarily secure bit commitment

Spatial Updating Strategy Affects the Reference Frame in Path Integration.

Science.gov (United States)

He, Qiliang; McNamara, Timothy P

2018-06-01

This study investigated how spatial updating strategies affected the selection of reference frames in path integration. Participants walked an outbound path consisting of three successive waypoints in a featureless environment and then pointed to the first waypoint. We manipulated the alignment of participants' final heading at the end of the outbound path with their initial heading to examine the adopted reference frame. We assumed that the initial heading defined the principal reference direction in an allocentric reference frame. In Experiment 1, participants were instructed to use a configural updating strategy and to monitor the shape of the outbound path while they walked it. Pointing performance was best when the final heading was aligned with the initial heading, indicating the use of an allocentric reference frame. In Experiment 2, participants were instructed to use a continuous updating strategy and to keep track of the location of the first waypoint while walking the outbound path. Pointing performance was equivalent regardless of the alignment between the final and the initial headings, indicating the use of an egocentric reference frame. These results confirmed that people could employ different spatial updating strategies in path integration (Wiener, Berthoz, & Wolbers Experimental Brain Research 208(1) 61-71, 2011), and suggested that these strategies could affect the selection of the reference frame for path integration.

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

Reference frame for Product Configuration

DEFF Research Database (Denmark)

Ladeby, Klaes Rohde; Oddsson, Gudmundur Valur

2011-01-01

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...

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

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...

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

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

Science.gov (United States)

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

2017-10-01

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

Frames of reference in spatial language acquisition.

Science.gov (United States)

Shusterman, Anna; Li, Peggy

2016-08-01

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

Contextual cueing of tactile search is coded in an anatomical reference frame.

Science.gov (United States)

Assumpção, Leonardo; Shi, Zhuanghua; Zang, Xuelian; Müller, Hermann J; Geyer, Thomas

2018-04-01

This work investigates the reference frame(s) underlying tactile context memory, a form of statistical learning in a tactile (finger) search task. In this task, if a searched-for target object is repeatedly encountered within a stable spatial arrangement of task-irrelevant distractors, detecting the target becomes more efficient over time (relative to nonrepeated arrangements), as learned target-distractor spatial associations come to guide tactile search, thus cueing attention to the target location. Since tactile search displays can be represented in several reference frames, including multiple external and an anatomical frame, in Experiment 1 we asked whether repeated search displays are represented in tactile memory with reference to an environment-centered or anatomical reference frame. In Experiment 2, we went on examining a hand-centered versus anatomical reference frame of tactile context memory. Observers performed a tactile search task, divided into a learning and test session. At the transition between the two sessions, we introduced postural manipulations of the hands (crossed ↔ uncrossed in Expt. 1; palm-up ↔ palm-down in Expt. 2) to determine the reference frame of tactile contextual cueing. In both experiments, target-distractor associations acquired during learning transferred to the test session when the placement of the target and distractors was held constant in anatomical, but not external, coordinates. In the latter, RTs were even slower for repeated displays. We conclude that tactile contextual learning is coded in an anatomical reference frame. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

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

Common Frame of Reference & social justice

NARCIS (Netherlands)

Hesselink, M.

2008-01-01

This paper evaluates the draft Common Frame of Reference (DCFR) in terms of social justice. It concludes the DCFR has all the characteristics of a typical European compromise. Ideological and esthetical purists will certainly be disappointed. In this respect, it has much in common with the

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

Science.gov (United States)

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

2008-01-01

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

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

Science.gov (United States)

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

2017-04-01

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

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

Current control of PMSM based on maximum torque control reference frame

Science.gov (United States)

Ohnuma, Takumi

2017-07-01

This study presents a new method of current controls of PMSMs (Permanent Magnet Synchronous Motors) based on a maximum torque control reference frame, which is suitable for high-performance controls of the PMSMs. As the issues of environment and energy increase seriously, PMSMs, one of the AC motors, are becoming popular because of their high-efficiency and high-torque density in various applications, such as electric vehicles, trains, industrial machines, and home appliances. To use the PMSMs efficiently, a proper current control of the PMSMs is necessary. In general, a rotational coordinate system synchronizing with the rotor is used for the current control of PMSMs. In the rotating reference frame, the current control is easier because the currents on the rotating reference frame can be expressed as a direct current in the controller. On the other hand, the torque characteristics of PMSMs are non-linear and complex; the PMSMs are efficient and high-density though. Therefore, a complicated control system is required to involve the relation between the torque and the current, even though the rotating reference frame is adopted. The maximum torque control reference frame provides a simpler way to control efficiently the currents taking the torque characteristics of the PMSMs into consideration.

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

Czech Academy of Sciences Publication Activity Database

Vondrák, Jan; Štefka, Vojtěch

2007-01-01

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

Representing Spatial Layout According to Intrinsic Frames of Reference.

Science.gov (United States)

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

2017-01-01

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

The resource theory of quantum reference frames: manipulations and monotones

International Nuclear Information System (INIS)

Gour, Gilad; Spekkens, Robert W

2008-01-01

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

On Translators' Cultural Frame of Functionist Reference

Science.gov (United States)

Fu, Zhiyi

2009-01-01

A deep cognition with translators' cultural frame of functionist reference can help instructors and teachers adjust and extend patterns and schemes of translation and generate the optimal classroom conditions for acquisition of the target language. The author of the paper, in the perspectives of motivational, cognitive and communicative…

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.

Optical position meters analyzed in the noninertial reference frames

International Nuclear Information System (INIS)

Tarabrin, Sergey P.; Seleznyov, Alexander A.

2008-01-01

In the framework of general relativity we develop a method for the analysis of the operation of the optical position meters in their photodetectors proper reference frames. These frames are noninertial in general due to the action of external fluctuative forces on meters test masses, including detectors. For comparison we also perform the calculations in the laboratory (globally inertial) reference frame and demonstrate that for certain optical schemes laboratory-based analysis results in unmeasurable quantities, in contrast to the detector-based analysis. We also calculate the response of the simplest optical meters to weak plane gravitational waves and fluctuative motions of their test masses. It is demonstrated that for the round-trip meter analysis in both the transverse-traceless (TT) and local Lorentz (LL) gauges produces equal results, while for the forward-trip meter corresponding results differ in accordance with different physical assumptions (e.g. procedure of clocks synchronization) implicitly underlying the construction of the TT and LL gauges.

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

National Research Council Canada - National Science Library

Kaplan, George H

2005-01-01

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

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

Science.gov (United States)

Tull, Ashley; Freeman, Jerrid P.

2011-01-01

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

A Modernized National Spatial Reference System in 2022: Focus on the Caribbean Terrestrial Reference Frame

Science.gov (United States)

Roman, D. R.

2017-12-01

In 2022, the National Geodetic Survey will replace all three NAD 83 reference frames the four new terrestrial reference frames. Each frame will be named after a tectonic plate (North American, Pacific, Caribbean and Mariana) and each will be related to the IGS frame through three Euler Pole parameters (EPPs). This talk will focus on practical application in the Caribbean region. A working group is being re-established for development of the North American region and will likely also result in analysis of the Pacific region as well. Both of these regions are adequately covered with existing CORS sites to model the EPPs. The Mariana region currently lacks sufficient coverage, but a separate project is underway to collect additional information to help in defining EPPs for that region at a later date. The Caribbean region has existing robust coverage through UNAVCO's COCONet and other data sets, but these require further analysis. This discussion will focus on practical examination of Caribbean sites to establish candidates for determining the Caribbean frame EPPs as well as an examination of any remaining velocities that might inform a model of the remaining velocities within that frame (Intra-Frame Velocity Model). NGS has a vested interest in defining such a model to meet obligations to U.S. citizens in Puerto Rico and the U.S. Virgin Islands. Beyond this, NGS aims to collaborate with other countries in the region through efforts with SIRGAS and UN-GGIM-Americas for a more acceptable regional model to serve everyone's needs.

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

Science.gov (United States)

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

2011-11-01

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

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.

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

Science.gov (United States)

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

2018-04-01

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

How Flexible is the Use of Egocentric Versus Allocentric Frame of Reference in the Williams Syndrome Population?

Science.gov (United States)

Heiz, J; Majerus, S; Barisnikov, K

2017-09-28

This study examined the spontaneous use of allocentric and egocentric frames of reference and their flexible use as a function of instructions. The computerized spatial reference task created by Heiz and Barisnikov (2015) was used. Participants had to choose a frame of reference according to three types of instructions: spontaneous, allocentric and egocentric. The performances of 16 Williams Syndrome participants between 10 and 41 years were compared to those of two control groups (chronological age and non-verbal intellectual ability). The majority of Williams Syndrome participants did not show a preference for a particular frame of reference. When explicitly inviting participants to use an allocentric frame of reference, all three groups showed an increased use of the allocentric frame of reference. At the same time, an important heterogeneity of type of frame of reference used by Williams Syndrome participants was observed. Results demonstrate that despite difficulties in the spontaneous use of allocentric and egocentric frames of reference, some Williams Syndrome participants show flexibility in the use of an allocentric frame of reference when an explicit instruction is provided. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

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.

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.

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

Science.gov (United States)

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

2013-01-01

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

Language and spatial frames of reference in mind and brain.

Science.gov (United States)

Gallistel, C R.

2002-08-01

Some language communities routinely use allocentric reference directions (e.g. 'uphill-downhill') where speakers of European languages would use egocentric references ('left-right'). Previous experiments have suggested that the different language groups use different reference frames in non-linguistic tasks involving the recreation of oriented arrays. However, a recent paper argues that manipulating test conditions produces similar effects in monolingual English speakers, and in animals.

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

International Nuclear Information System (INIS)

Klink, W.H.; Wickramasekara, S.

2014-01-01

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

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...

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.

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

Science.gov (United States)

Skotiniotis, Michael

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

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

DEFF Research Database (Denmark)

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

2014-01-01

Control of three-phase power converters in the synchronous reference frame is now a mature and well developed research topic. However, for single-phase converters, it is not as well-established as three-phase applications. This paper deals with the design of a synchronous reference frame multi-lo...... on a frequency response approach is presented. Finally, the theoretical achievements are supported by experimental results.......-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...

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.

Location memory biases reveal the challenges of coordinating visual and kinesthetic reference frames

Science.gov (United States)

Simmering, Vanessa R.; Peterson, Clayton; Darling, Warren; Spencer, John P.

2008-01-01

Five experiments explored the influence of visual and kinesthetic/proprioceptive reference frames on location memory. Experiments 1 and 2 compared visual and kinesthetic reference frames in a memory task using visually-specified locations and a visually-guided response. When the environment was visible, results replicated previous findings of biases away from the midline symmetry axis of the task space, with stability for targets aligned with this axis. When the environment was not visible, results showed some evidence of bias away from a kinesthetically-specified midline (trunk anterior–posterior [a–p] axis), but there was little evidence of stability when targets were aligned with body midline. This lack of stability may reflect the challenges of coordinating visual and kinesthetic information in the absence of an environmental reference frame. Thus, Experiments 3–5 examined kinesthetic guidance of hand movement to kinesthetically-defined targets. Performance in these experiments was generally accurate with no evidence of consistent biases away from the trunk a–p axis. We discuss these results in the context of the challenges of coordinating reference frames within versus between multiple sensori-motor systems. PMID:17703284

Cross-Sensory Transfer of Reference Frames in Spatial Memory

Science.gov (United States)

Kelly, Jonathan W.; Avraamides, Marios N.

2011-01-01

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

Developing a Frame of Reference for understanding configuration systems

DEFF Research Database (Denmark)

Ladeby, Klaes Rohde; Edwards, Kasper

2008-01-01

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

Different reference frames can lead to different hand transplantation decisions by patients and physicians.

Science.gov (United States)

Edgell, S E; McCabe, S J; Breidenbach, W C; Neace, W P; LaJoie, A S; Abell, T D

2001-03-01

Different frames of reference can affect one's assessment of the value of hand transplantation. This can result in different yet rational decisions by different groups of individuals, especially patients and physicians. In addition, factors other than frames of reference can affect one's evaluation of hand transplantation, which can result in different decisions.

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

Berry's phase factors in moving frames of reference and their observable effects

International Nuclear Information System (INIS)

Sun Changpu; Zhang Linzhi

1990-01-01

Under non-relativistic conditions, the properties of adiabatic solutions of the Schroedinger equation in moving frame of reference and the behaviours of the corresponding Berry's Phase are analysed. Two cases of translation and rotation are discussed in detail, which show that the existence of Berry's phase depends on the choice of frame of reference. While Bitter and Dubbers's experiment is explained by the first-order approximation in the discussion. The non-adiabatic effects in this experiment are predicted by the second-order approximation when the adiabatic condition is broken

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

Shift of the spectrum in the non-inertial reference frame

International Nuclear Information System (INIS)

Kudykina, T. A.; Pervak, A. I.

2012-01-01

We propose a new natural explanation of the spectral redshift (blue shift) arguing that the rotatory non-inertial reference frame of cosmological objects is the main reason of the shift of the frequency of emitting light. (Author)

A consistent time frame for Chaucer's Canterbury Pilgrimage

Science.gov (United States)

Kummerer, K. R.

2001-08-01

A consistent time frame for the pilgrimage that Geoffrey Chaucer describes in The Canterbury Tales can be established if the seven celestial assertions related to the journey mentioned in the text can be reconciled with each other and the date of April 18 that is also mentioned. Past attempts to establish such a consistency for all seven celestial assertions have not been successful. The analysis herein, however, indicates that in The Canterbury Tales Chaucer accurately describes the celestial conditions he observed in the April sky above the London(Canterbury region of England in the latter half of the fourteenth century. All seven celestial assertions are in agreement with each other and consistent with the April 18 date. The actual words of Chaucer indicate that the Canterbury journey began during the 'seson' he defines in the General Prologue and ends under the light of the full Moon on the night of April 18, 1391.

Generalized frame of reference with null congruence

International Nuclear Information System (INIS)

Ferrarese, G.; Antonelli, R.

2000-01-01

The paper derives the main properties of a generalized frame of reference with a null congruence (light flux), by means of adapted non-holonomic techniques; then it studies the geometry of the space-time in terms of non-orthogonal projection: longitudinal and transverse covariant derivatives and corresponding commutation formulae, decomposition of the Riemann and gravitational tensors, lie derivatives of the Ricci rotation coefficients, transverse Bianchi identity. Application to the (absolute and relative) light flux: kinematical characteristics and screen, Sachs theorems etc. are also given

Search for evidence of a preferred reference frame

International Nuclear Information System (INIS)

Warburton, R.J.; Goodkind, J.M.

1976-01-01

Some gravity theories, in contradiction to general relativity, allow the existence of a universal preferred reference frame. Also allowed in some theories can be a galaxy-induced anisotropy of the gravitation constant. The parametrized post-Newtonian theory predicts that in these cases there will be anomalous Earth tide amplitudes at specific frequencies. An 18-month Earth tide record obtained with the superconducting gravimeter has been examined for such anomalies. The data allow for the existence of such effects but cannot prove it because of uncertainties concerning geophysical perturbations of the tides. However, an upper limit to the preferred frame parameter, α 2 , of the parametrized post-Newtonian formalism is established at 2 x 10 -3 . The results also set a less rigorous limit on the anisotropy parameter, zeta/sub omega/, of order 10 -3

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

International Nuclear Information System (INIS)

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

2004-01-01

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

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

Ipsilateral wrist-ankle movements in the sagittal plane encoded in extrinsic reference frame.

Science.gov (United States)

Muraoka, Tetsuro; Ishida, Yuki; Obu, Takashi; Crawshaw, Larry; Kanosue, Kazuyuki

2013-04-01

When performing oscillatory movements of two joints in the sagittal plane, there is a directional constraint for performing such movements. Previous studies could not distinguish whether the directional constraint reflected movement direction encoded in the extrinsic (outside the body) reference frame or in the intrinsic (the participants' torso/head) reference frame since participants performed coordinated movements in a sitting position where the torso/head was stationary relative to the external world. In order to discern the reference frame in the present study, participants performed paced oscillatory movements of the ipsilateral wrist and ankle in the sagittal plane in a standing position so that the torso/head moved relative to the external world. The coordinated movements were performed in one of two modes of coordination, moving the hand upward concomitant with either ankle plantarflexion or ankle dorsiflexion. The same directional mode relative to extrinsic space was more stable and accurate as compared with the opposite directional mode. When forearm position was changed from the pronated position to the supinated position, similar results were obtained, indicating that the results were independent of a particular coupling of muscles. These findings suggest that the directional constraint on ipsilateral joints movements in the sagittal plane reflects movement direction encoded in the extrinsic reference frame. Copyright © 2013 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

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

CERN Document Server

Beutler, Gerhard

2005-01-01

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

Exploring students' understanding of reference frames and time in Galilean and special relativity

International Nuclear Information System (INIS)

De Hosson, C; Kermen, I; Parizot, E

2010-01-01

This paper aims at exploring prospective physics teachers' reasoning associated with the concepts of reference frame, time and event which form the framework of the classical kinematics and that of the relativistic kinematics. About 100 prospective physics teachers were surveyed by means of a questionnaire involving classical kinematics situations and relativistic ones. The analysis of the answers shows a deep lack of understanding of both concepts of reference frame and event. Some students think that events may be simultaneous for an observer and not simultaneous for another one, even when both observers are located in the same reference frame. Most of the students surveyed cannot give an answer only depending on the location of the observer when his/her velocity is mentioned as if the movement contaminated the event. This lack of understanding is embodied in reasoning implemented by the population surveyed to address classical kinematics questions and seems to form a major obstacle to grasping relativistic kinematics.

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.

The effect of the reference frame on the thermophysical properties of an ideal gas

International Nuclear Information System (INIS)

Speziale, Cg.

1986-01-01

The effect that the frame of reference has on the thermophysical properties of an ideal gas is examined from a fundamental theoretical standpoint based on the Boltzmann equation. In continuum mechanics, the principle of material frame in deference forbids the thermophysical properties of a fluid or solid to depend in any way on the motion of the reference frame. It is demonstrated that the Boltzmann equation is only consistent with material frame-indeffrence in a strong approximate sense provided that the gas is not highly rarefield and, thus, well within the limits of classical continuum mechanics. Estimates of the mean free times for which material frame-indifference can be invoked in the modeling of gas flows are provided from an analysis of the problem of heat conduction in a rigidly rotating gas. Applications of these results in obtaining asymptotic solutions of the Boltzmann equation for the continuum description of an ideal gas are discussed briefly

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

Science.gov (United States)

Hudson, Kerry D; Farran, Emily K

2017-09-01

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

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...... (referenced by the personal pronouns "he/she/it") in a previously-shown image relative to either themselves (egocentric reference frame) or shifted to a reference frame anchored in another person or object in the image (allocentric reference frame), e.g. "Was he in front of you/her?" Good performers had both...... shorter response time and more correct responses than poor performers in both tasks. These behavioural variables were entered into a principal component analysis. The first component reflected generalised performance level. We found that the frontal eye fields (FEF), bilaterally, had a higher BOLD...

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

How role distribution influences choice of spatial reference frames in a virtual collaborative task

OpenAIRE

Pouliquen-Lardy , Lauriane; Milleville-Pennel , Isabelle; Guillaume , François; Mars , Franck

2014-01-01

International audience; We investigated the effects of role distribution on individuals' choice of reference frames in a two-person task. Pairs of participants had to move a virtual block in a constraint immersive virtual environment: only one of them could manipulate the ob-ject, his coworker guided him in the VE. Results show that the guiding operators used more addressee-centered frames of ref-erence than the manipulators. They also suggest that the guides tried to facilitate the manipulat...

Frames of Reference and Some of its Applications

OpenAIRE

Bel, Ll.

1998-01-01

We define a Frame of reference as a two ingredients concept: A meta-rigid motion, which is a generalization of a Born motion, and a chorodesic synchronization, which is an adapted foliation. At the end of the line we uncover a low-level 3-dimensional geometry with constant curvature and a corresponding coordinated proper-time scale. We discuss all these aspects both from the geometrical point of view as from the point of view of some of the physical applications derived from them.

A Snapshot-Based Mechanism for Celestial Orientation.

Science.gov (United States)

El Jundi, Basil; Foster, James J; Khaldy, Lana; Byrne, Marcus J; Dacke, Marie; Baird, Emily

2016-06-06

In order to protect their food from competitors, ball-rolling dung beetles detach a piece of dung from a pile, shape it into a ball, and roll it away along a straight path [1]. They appear to rely exclusively on celestial compass cues to maintain their bearing [2-8], but the mechanism that enables them to use these cues for orientation remains unknown. Here, we describe the orientation strategy that allows dung beetles to use celestial cues in a dynamic fashion. We tested the underlying orientation mechanism by presenting beetles with a combination of simulated celestial cues (sun, polarized light, and spectral cues). We show that these animals do not rely on an innate prediction of the natural geographical relationship between celestial cues, as other navigating insects seem to [9, 10]. Instead, they appear to form an internal representation of the prevailing celestial scene, a "celestial snapshot," even if that scene represents a physical impossibility for the real sky. We also find that the beetles are able to maintain their bearing with respect to the presented cues only if the cues are visible when the snapshot is taken. This happens during the "dance," a behavior in which the beetle climbs on top of its ball and rotates about its vertical axis [11]. This strategy for reading celestial signals is a simple but efficient mechanism for straight-line orientation. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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

2018-04-01

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

Angular distribution of large qsub(T) muon pairs in different reference frames

International Nuclear Information System (INIS)

Lindfors, J.

1979-01-01

The angular distribution of large transverse momentum muon pairs produced in hadron-hadron collisions is calculated in lowest order of perturbative QCD. It is shown that for the process quark-antiquark → gluon + μ + μ - the polar and azimuthal angle distributions can be made independent of the parton distributions by choosing a special reference frame, the Collins-Soper frame, but for the process quark + gluon → quark + μ + μ - this is not possible. (author)

On the Assessment of Global Terrestrial Reference Frame Temporal Variations

Science.gov (United States)

Ampatzidis, Dimitrios; Koenig, Rolf; Zhu, Shengyuan

2015-04-01

Global Terrestrial Reference Frames (GTRFs) as the International Terrestrial Reference Frame (ITRF) provide reliable 4-D position information (3-D coordinates and their evolution through time). The given 3-D velocities play a significant role in precise position acquisition and are estimated from long term coordinate time series from the space-geodetic techniques DORIS, GNSS, SLR, and VLBI. GTRFs temporal evolution is directly connected with their internal stability: The more intense and inhomogeneous velocity field, the less stable TRF is derived. The assessment of the quality of the GTRF is mainly realized by comparing it to each individual technique's reference frame. E.g the comparison of GTRFs to SLR-only based TRF gives the sense of the ITRF stability with respect to the Geocenter and scale and their associated rates respectively. In addition, the comparison of ITRF to the VLBI-only based TRF can be used for the scale validation. However, till now there is not any specified methodology for the total assessment (in terms of origin, orientation and scale respectively) of the temporal evolution and GTRFs associated accuracy. We present a new alternative diagnostic tool for the assessment of GTRFs temporal evolution based on the well-known time-dependent Helmert type transformation formula (three shifts, three rotations and scale rates respectively). The advantage of the new methodology relies on the fact that it uses the full velocity field of the TRF and therefore all points not just the ones common to different techniques. It also examines simultaneously rates of origin, orientation and scale. The methodology is presented and implemented to the two existing GTRFs on the market (ITRF and DTRF which is computed from DGFI) , the results are discussed. The results also allow to compare directly each GTRF dynamic behavior. Furthermore, the correlations of the estimated parameters can also provide useful information to the proposed GTRFs assessment scheme.

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.

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....

The Gaia inertial reference frame and the tilting of the Milky Way disk

International Nuclear Information System (INIS)

Perryman, Michael; Spergel, David N.; Lindegren, Lennart

2014-01-01

While the precise relationship between the Milky Way disk and the symmetry planes of the dark matter halo remains somewhat uncertain, a time-varying disk orientation with respect to an inertial reference frame seems probable. Hierarchical structure formation models predict that the dark matter halo is triaxial and tumbles with a characteristic rate of ∼2 rad H 0 −1 (∼30 μas yr –1 ). These models also predict a time-dependent accretion of gas, such that the angular momentum vector of the disk should be misaligned with that of the halo. These effects, as well as tidal effects of the LMC, will result in the rotation of the angular momentum vector of the disk population with respect to the quasar reference frame. We assess the accuracy with which the positions and proper motions from Gaia can be referred to a kinematically non-rotating system, and show that the spin vector of the transformation from any rigid self-consistent catalog frame to the quasi-inertial system defined by quasars should be defined to better than 1 μas yr –1 . Determination of this inertial frame by Gaia will reveal any signature of the disk orientation varying with time, improve models of the potential and dynamics of the Milky Way, test theories of gravity, and provide new insights into the orbital evolution of the Sagittarius dwarf galaxy and the Magellanic Clouds.

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...

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

Science.gov (United States)

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

2007-01-01

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

Entanglement detection with bounded reference frames

International Nuclear Information System (INIS)

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

2009-01-01

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

Design of all-weather celestial navigation system

Science.gov (United States)

Sun, Hongchi; Mu, Rongjun; Du, Huajun; Wu, Peng

2018-03-01

In order to realize autonomous navigation in the atmosphere, an all-weather celestial navigation system is designed. The research of celestial navigation system include discrimination method of comentropy and the adaptive navigation algorithm based on the P value. The discrimination method of comentropy is studied to realize the independent switching of two celestial navigation modes, starlight and radio. Finally, an adaptive filtering algorithm based on P value is proposed, which can greatly improve the disturbance rejection capability of the system. The experimental results show that the accuracy of the three axis attitude is better than 10″, and it can work all weather. In perturbation environment, the position accuracy of the integrated navigation system can be increased 20% comparing with the traditional method. It basically meets the requirements of the all-weather celestial navigation system, and it has the ability of stability, reliability, high accuracy and strong anti-interference.

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...

The Influence of the Terrestrial Reference Frame on Studies of Sea Level Change

Science.gov (United States)

Nerem, R. S.; Bar-Sever, Y. E.; Haines, B. J.; Desai, S.; Heflin, M. B.

2015-12-01

The terrestrial reference frame (TRF) provides the foundation for the accurate monitoring of sea level using both ground-based (tide gauges) and space-based (satellite altimetry) techniques. For the latter, tide gauges are also used to monitor drifts in the satellite instruments over time. The accuracy of the terrestrial reference frame (TRF) is thus a critical component for both types of sea level measurements. The TRF is central to the formation of geocentric sea-surface height (SSH) measurements from satellite altimeter data. The computed satellite orbits are linked to a particular TRF via the assumed locations of the ground-based tracking systems. The manner in which TRF errors are expressed in the orbit solution (and thus SSH) is not straightforward, and depends on the models of the forces underlying the satellite's motion. We discuss this relationship, and provide examples of the systematic TRF-induced errors in the altimeter derived sea-level record. The TRF is also crucial to the interpretation of tide-gauge measurements, as it enables the separation of vertical land motion from volumetric changes in the water level. TRF errors affect tide gauge measurements through GNSS estimates of the vertical land motion at each tide gauge. This talk will discuss the current accuracy of the TRF and how errors in the TRF impact both satellite altimeter and tide gauge sea level measurements. We will also discuss simulations of how the proposed Geodetic Reference Antenna in SPace (GRASP) satellite mission could reduce these errors and revolutionize how reference frames are computed in general.

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

Science.gov (United States)

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

1994-01-01

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

Dissociating contributions of head and torso to spatial reference frames

DEFF Research Database (Denmark)

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

2017-01-01

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

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

NARCIS (Netherlands)

Ee, R. van; Erkelens, Casper J.

1995-01-01

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

The assessment of the transformation of global tectonic plate models and the global terrestrial reference frames using the Velocity Decomposition Analysis

Science.gov (United States)

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

2016-04-01

The aim of our study is to assess the classical Helmert similarity transformation using the Velocity Decomposition Analysis (VEDA). The VEDA is a new methodology, developed by GFZ for the assessment of the reference frames' temporal variation and it is based on the separation of the velocities into two specified parts: The first is related to the reference system choice (the so called datum effect) and the latter one which refers to the real deformation of the terrestrial points. The advantage of the VEDA is its ability to detect the relative biases and reference system effects between two different frames or two different realizations of the same frame, respectively. We apply the VEDA for the assessment between several modern tectonic plate models and the recent global terrestrial reference frames.

An accelerating reference frame for electromagnetic waves in a rapidly growing plasma

International Nuclear Information System (INIS)

Yablonovitch, E.

1989-01-01

In 1974, Hawking showed that black holes can evaporate by the emission of low temperature thermal radiation, now named Hawking radiation. Shortly thereafter, a closely related effect called Unruh radiation became apparent. The author discusses how, according to Unruh and Davies, observers of the electromagnetic field in an accelerating reference frame should see thermal radiation at a temperature T: KT = h/2π a/c where a is the acceleration relative to an inertial frame, c is the speed of light and h and K are Planck's and Boltzmann's constant respectively. In a frame accelerating at g = 980 cm/sec 2 , equivalent to the acceleration experienced at the earth's surface, this thermal radiation is at a temperature of only 4 x 10 -20 degrees K. Therefore, physicists hoping to observe this radiation, have sought out systems being subjected to extreme acceleration

Quantum reference frames and quantum transformations

International Nuclear Information System (INIS)

Toller, M.

1997-01-01

A quantum frame is defined by a material object following the laws of quantum mechanics. The present paper studies the relations between quantum frames, which are described by some generalization of the Poincare' group. The possibility of using a suitable quantum group is examined, but some arguments are given which show that a different mathematical structure is necessary. Some simple examples in lower-dimensional space-times are treated. They indicate the necessity of taking into account some ''internal'' degrees of freedom of the quantum frames, that can be disregarded in a classical treatment

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

International Nuclear Information System (INIS)

Kopeikin, Sergei; Vlasov, Igor

2004-01-01

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

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.

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.

Celestial Navigation on the Surface of Mars

Science.gov (United States)

Malay, Benjamin P.

2001-05-01

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

Light escape cones in local reference frames of Kerr-de Sitter black hole spacetimes and related black hole shadows

Science.gov (United States)

Stuchlík, Zdeněk; Charbulák, Daniel; Schee, Jan

2018-03-01

We construct the light escape cones of isotropic spot sources of radiation residing in special classes of reference frames in the Kerr-de Sitter (KdS) black hole spacetimes, namely in the fundamental class of `non-geodesic' locally non-rotating reference frames (LNRFs), and two classes of `geodesic' frames, the radial geodesic frames (RGFs), both falling and escaping, and the frames related to the circular geodesic orbits (CGFs). We compare the cones constructed in a given position for the LNRFs, RGFs, and CGFs. We have shown that the photons locally counter-rotating relative to LNRFs with positive impact parameter and negative covariant energy are confined to the ergosphere region. Finally, we demonstrate that the light escaping cones govern the shadows of black holes located in front of a radiating screen, as seen by the observers in the considered frames. For shadows related to distant static observers the LNRFs are relevant.

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

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

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

Science.gov (United States)

Vercillo, Tiziana; Tonelli, Alessia; Gori, Monica

2018-01-01

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

The use of the empirical mode decomposition for the identification of mean field aligned reference frames

Directory of Open Access Journals (Sweden)

Mauro Regi

2017-01-01

Full Text Available The magnetic field satellite data are usually referred to geocentric coordinate reference frame. Conversely, the magnetohydrodynamic waves modes in magnetized plasma depend on the ambient magnetic field, and is then useful to rotate the magnetic field measurements into the mean field aligned (MFA coordinate system. This reference frame is useful to study the ultra low frequency magnetic field variations along the direction of the mean field and perpendicularly to it. In order to identify the mean magnetic field the classical moving average (MAVG approach is usually adopted but, under particular conditions, this procedure induces undesired features, such as spectral alteration in the rotated components. We discuss these aspects promoting an alternative and more efficient method for mean field aligned projection, based on the empirical mode decomposition (EMD.

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. ...

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

Science.gov (United States)

Hofmann, Franz; Biskupek, Liliane; Müller, Jürgen

2018-01-01

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

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...

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

Directory of Open Access Journals (Sweden)

Valeria Ivanova Petkova

2011-03-01

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

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

Science.gov (United States)

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

2011-01-01

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

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...

The frames of reference of the motor-visual aftereffect.

Directory of Open Access Journals (Sweden)

Guido Barchiesi

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

Operationalization of a Frame of Reference for Studying Organizational Culture in Middle Schools.

Science.gov (United States)

Daniel, Larry G.

A frame of reference for studying culture in middle schools was developed. Items for the Middle School Description Survey (MSDS), which was designed to test elements of the ideal middle school culture, were created based on middle school advocacy literature. The items were conceptually categorized according to E. H. Schein's (1985) cultural…

Entanglement and symmetry: A case study in superselection rules, reference frames, and beyond

International Nuclear Information System (INIS)

Jones, S. J.; Wiseman, H. M.; Vaccaro, J. A.; Pope, D. T.; Bartlett, S. D.

2006-01-01

In recent years it has become apparent that constraints on possible quantum operations, such as those constraints imposed by superselection rules (SSRs), have a profound effect on quantum information theoretic concepts like bipartite entanglement. This paper concentrates on a particular example: the constraint that applies when the parties (Alice and Bob) cannot distinguish among certain quantum objects they have. This arises naturally in the context of ensemble quantum information processing such as in liquid NMR. We discuss how a SSR for the symmetric group can be applied, and show how the extractable entanglement can be calculated analytically in certain cases, with a maximum bipartite entanglement in an ensemble of N Bell-state pairs scaling as log(N) as N→∞. We discuss the apparent disparity with the asymptotic (N→∞) recovery of unconstrained entanglement for other sorts of superselection rules, and show that the disparity disappears when the correct notion of applying the symmetric group SSR to multiple copies is used. Next we discuss reference frames in the context of this SSR, showing the relation to the work of von Korff and Kempe [Phys. Rev. Lett. 93, 260502 (2004)]. The action of a reference frame can be regarded as the analog of activation in mixed-state entanglement. We also discuss the analog of distillation: there exist states such that one copy can act as an imperfect reference frame for another copy. Finally we present an example of a stronger operational constraint, that operations must be noncollective as well as symmetric. Even under this stronger constraint we, nevertheless, show that Bell nonlocality (and hence entanglement) can be demonstrated for an ensemble of N Bell-state pairs no matter how large N is. This last work is a generalization of that of Mermin [Phys. Rev. D 22, 356 (1980)

Relativistic celestial mechanics with PPN parameters

Science.gov (United States)

Klioner, Sergei A.; Soffel, Michael H.

2000-07-01

Starting from the global parametrized post-Newtonian (PPN) reference system with two PPN parameters γ and β we consider a space-bounded subsystem of matter and construct a local reference system for that subsystem in which the influence of external masses reduces to tidal effects. Both the metric tensor of the local PPN reference system in the first post-Newtonian approximation as well as the coordinate transformations between the global PPN reference system and the local one are constructed in explicit form. The terms proportional to η=4β-γ-3 reflecting a violation of the equivalence principle are discussed in detail. We suggest an empirical definition of multipole moments which are intended to play the same role in PPN celestial mechanics as the Blanchet-Damour moments in general relativity. We also show that the tidal gravitational field as seen in the local PPN reference system can be expanded into powers of local coordinates similar to the tidal expansion in general relativity. Starting with the metric tensor in the local PPN reference system we derive translational equations of motion of a test particle (an Earth satellite) in that system. The translational and rotational equations of motion for center of mass and spin of each of N extended massive bodies possessing arbitrary multipole structure are derived. All equations of motion are presented also in the form of multipole expansions. Several interesting features of the equations are discussed. As an application of the general equations of motion a monopole-spin dipole model is considered and the known PPN equations of motion of mass monopoles with spins are rederived. For the first time, these equations are derived in a self-consistent manner which does not require any additional assumptions about the behavior of bodies such as secular stationarity.

The draft common frame of reference (DCFR) : A giant with feet of clay

NARCIS (Netherlands)

Chirico, F.; van Damme, E.E.C.; Larouche, P.; Larouche, P.; Cserne, P.

2013-01-01

This chapter summarizes the lessons drawn from the work of the Economic Impact Group (EIG), a part of the CoPECL Network of Excellence funded by the EU to prepare a Draft Common Frame of Reference (DCFR). First, it revisits basic principles which are central to the work of the whole group. For one,

The Celestial Vault: The Magic of Astrology

Science.gov (United States)

McGaha, J.

2004-11-01

Astrology is a "Geocentric System" that supports the "Astrological Principle". This principle, that human beings and their actions are influenced by the positions of celestial objects, is not objectively supported. The "planetary gods" found in the heavens provided order to help explain the chaotic events in life on earth. Is this why many people think their horoscopes are correct, with the "stars" taking credit? Do "celestial movements" foretell the future? What is the evidence for Astrology? The historical, psychological and physical foundations of astrology will be discussed.

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 whic...

Classical field theory in the space of reference frames. [Space-time manifold, action principle

Energy Technology Data Exchange (ETDEWEB)

Toller, M [Dipartimento di Matematica e Fisica, Libera Universita, Trento (Italy)

1978-03-11

The formalism of classical field theory is generalized by replacing the space-time manifold M by the ten-dimensional manifold S of all the local reference frames. The geometry of the manifold S is determined by ten vector fields corresponding to ten operationally defined infinitesimal transformations of the reference frames. The action principle is written in terms of a differential 4-form in the space S (the Lagrangian form). Densities and currents are represented by differential 3-forms in S. The field equations and the connection between symmetries and conservation laws (Noether's theorem) are derived from the action principle. Einstein's theory of gravitation and Maxwell's theory of electromagnetism are reformulated in this language. The general formalism can also be used to formulate theories in which charge, energy and momentum cannot be localized in space-time and even theories in which a space-time manifold cannot be defined exactly in any useful way.

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

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

Directory of Open Access Journals (Sweden)

Jakub Limanowski

2018-03-01

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

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

Science.gov (United States)

Limanowski, Jakub; Blankenburg, Felix

2018-01-01

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

Contribution of Multi-GNSS Constellation to SLR-Derived Terrestrial Reference Frame

Science.gov (United States)

Sośnica, K.; Bury, G.; Zajdel, R.

2018-03-01

All satellites of new Global Navigation Satellite Systems (GNSS) are equipped with laser retroreflectors dedicated to Satellite Laser Ranging (SLR). This paper demonstrates the contribution of SLR tracking of multi-GNSS constellations to the improved SLR-derived reference frame and scientific products. We show a solution strategy with estimating satellite orbits, SLR station coordinates, geocenter coordinates, and Earth rotation parameters using SLR observations to 2 Laser Geodynamics Satellites (LAGEOS) and 55 GNSS satellites: 1 GPS, 31 Globalnaya Navigatsionnaya Sputnikovaya Sistema, 18 Galileo, 3 BeiDou Inclined Geosynchronous Orbit, 1 BeiDou Medium Earth Orbit, and 1 Quasi-Zenith Satellite System satellite for the period 2014.0-2017.4. Due to a substantial number of GNSS observations, the number of weekly solutions for some SLR stations, for example, Arkhyz, Komsomolsk, Altay, and Brasilia, is larger up to 41% in the combined LAGEOS + GNSS solution when compared to the LAGEOS-only solution. The SLR observations to GNSS can transfer the orientation of the reference frame from GNSS to SLR solutions. As a result, the SLR-derived pole coordinates and length-of-day estimates become more consistent with GNSS microwave-based results. The root-mean-square errors of length-of-day are reduced from 122.5 μs/d to 43.0 μs/d, whereas mean offsets are reduced from -81.6 μs/d to 0.5 μs/d in LAGEOS only and in the combined LAGEOS + GNSS solutions, respectively.

Locations of serial reach targets are coded in multiple reference frames.

Science.gov (United States)

Thompson, Aidan A; Henriques, Denise Y P

2010-12-01

Previous work from our lab, and elsewhere, has demonstrated that remembered target locations are stored and updated in an eye-fixed reference frame. That is, reach errors systematically vary as a function of gaze direction relative to a remembered target location, not only when the target is viewed in the periphery (Bock, 1986, known as the retinal magnification effect), but also when the target has been foveated, and the eyes subsequently move after the target has disappeared but prior to reaching (e.g., Henriques, Klier, Smith, Lowy, & Crawford, 1998; Sorrento & Henriques, 2008; Thompson & Henriques, 2008). These gaze-dependent errors, following intervening eye movements, cannot be explained by representations whose frame is fixed to the head, body or even the world. However, it is unknown whether targets presented sequentially would all be coded relative to gaze (i.e., egocentrically/absolutely), or if they would be coded relative to the previous target (i.e., allocentrically/relatively). It might be expected that the reaching movements to two targets separated by 5° would differ by that distance. But, if gaze were to shift between the first and second reaches, would the movement amplitude between the targets differ? If the target locations are coded allocentrically (i.e., the location of the second target coded relative to the first) then the movement amplitude should be about 5°. But, if the second target is coded egocentrically (i.e., relative to current gaze direction), then the reaches to this target and the distances between the subsequent movements should vary systematically with gaze as described above. We found that requiring an intervening saccade to the opposite side of 2 briefly presented targets between reaches to them resulted in a pattern of reaching error that systematically varied as a function of the distance between current gaze and target, and led to a systematic change in the distance between the sequential reach endpoints as predicted by

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

Coherence between geophysical excitations and celestial pole offsets

Czech Academy of Sciences Publication Activity Database

Ron, Cyril; Vondrák, Jan

2011-01-01

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

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

Science.gov (United States)

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

2016-01-01

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

Differential School Contextual Effects for Math and English: Integrating the Big-Fish-Little-Pond Effect and the Internal/External Frame of Reference

Science.gov (United States)

Parker, Philip D.; Marsh, Herbert W.; Ludtke, Oliver; Trautwein, Ulrich

2013-01-01

The internal/external frame of reference and the big-fish-little-pond effect are two major models of academic self-concept formation which have considerable theoretical and empirical support. Integrating the domain specific and compensatory processes of the internal/external frame of reference model with the big-fish-little-pond effect suggests a…

Dynamics of Natural and Artificial Celestial Bodies

Science.gov (United States)

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

2002-01-01

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

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

Science.gov (United States)

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

2018-06-01

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

Archaic artifacts resembling celestial spheres

Science.gov (United States)

Dimitrakoudis, S.; Papaspyrou, P.; Petoussis, V.; Moussas, X.

We present several bronze artifacts from the Archaic Age in Greece (750-480 BC) that resemble celestial spheres or forms of other astronomical significance. They are studied in the context of the Dark Age transition from Mycenaean Age astronomical themes to the philosophical and practical revival of astronomy in the Classical Age with its plethora of astronomical devices. These artifacts, mostly votive in nature are spherical in shape and appear in a variety of forms their most striking characteristic being the depiction of meridians and/or an equator. Most of those artifacts come from Thessaly, and more specifically from the temple of Itonia Athena at Philia, a religious center of pan-Hellenic significance. Celestial spheres, similar in form to the small artifacts presented in this study, could be used to measure latitudes, or estimate the time at a known place, and were thus very useful in navigation.

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

Science.gov (United States)

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

2018-04-01

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

Does Environmental Experience Shape Spatial Cognition? Frames of Reference among Ancash Quechua Speakers (Peru)

Science.gov (United States)

Shapero, Joshua A.

2017-01-01

Previous studies have shown that language contributes to humans' ability to orient using landmarks and shapes their use of frames of reference (FoRs) for memory. However, the role of environmental experience in shaping spatial cognition has not been investigated. This study addresses such a possibility by examining the use of FoRs in a nonverbal…

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

KAUST Repository

Chaoui, Hicham

2017-01-10

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

Optical monitoring of QSO in the framework of the Gaia space mission

Science.gov (United States)

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

2015-08-01

The Gaia astrometric mission of the European Space Agency has been launched the 19th December 2013. It will provide an astrometric catalogue of 500 000 extragalactic sources that could be the basis of a new optical reference frame. On the other hand, the current International Celestial Reference Frame (ICRF) is based on the observations of extragalactic sources at radio wavelength. The astrometric coordinates of sources in these two reference systems will have roughly the same uncertainty. It is then mandatory to observe a set of common targets at both optical and radio wavelength to link the ICRF with what could be called the GCRF (Gaia Celestial Reference Frame). We will show in this paper some results obtained with the TJO, Telescopi Juan Oro, from Observatori Astronomic del Montsec in Spain. It also presents some results obtained with the Lomb-Scargle and CLEAN algorithm methods applied to optical magnitude obtained with the TAROT telescopes.

Quantum cosmology with effects of a preferred reference frame

International Nuclear Information System (INIS)

Ghaffarnejad, Hossein

2010-01-01

Recently, we presented a gravity model by generalizing the Brans-Dicke theory which is suitable for studying the metric signature transition dynamics without using an imaginary time parameter. Adding a suitable scalar potential described in terms of the Brans-Dicke scalar field 'Φ-tilde, this alternative theory is used to study the Wheeler-DeWitt approach of quantum cosmology. We assumed that the universe is defined in a flat Robertson-Walker metric with Lorentzian signature. In that case, the Wheeler-DeWitt wavefunctional is obtained as two-dimensional quantum harmonic oscillator convergent polynomials for both of the choices of positive and negative values of the Brans-Dicke parameter. Here we choose a preferred reference frame with a time coordinate of 'γ' which relates to time of cosmological free falling observer 't' as 'dt= Φ-tilde(γ)dγ'.

Anandan quantum phase for a neutral particle with Fermi-Walker reference frame in the cosmic string background

International Nuclear Information System (INIS)

Bakke, Knut; Furtado, C.

2010-01-01

We study geometric quantum phases in the relativistic and non-relativistic quantum dynamics of a neutral particle with a permanent magnetic dipole moment interacting with two distinct field configurations in a cosmic string spacetime. We consider the local reference frames of the observers are transported via Fermi-Walker transport and study the influence of the non-inertial effects on the phase shift of the wave function of the neutral particle due to the choice of this local frame. We show that the wave function of the neutral particle acquires non-dispersive relativistic and non-relativistic quantum geometric phases due to the topology of the spacetime, the interaction between the magnetic dipole moment with external fields and the spin-rotation coupling. However, due to the Fermi-Walker reference frame, no phase shift associated to the Sagnac effect appears in the quantum dynamics of a neutral particle. We show that in the absence of topological defect, the contribution to the quantum phase due to the spin-rotation coupling is equivalent to the Mashhoon effect in non-relativistic dynamics. (orig.)

Media Framing

DEFF Research Database (Denmark)

Pedersen, Rasmus T.

2017-01-01

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

Device-dependent and device-independent quantum key distribution without a shared reference frame

International Nuclear Information System (INIS)

Slater, Joshua A; Tittel, Wolfgang; Branciard, Cyril; Brunner, Nicolas

2014-01-01

Standard quantum key distribution (QKD) protocols typically assume that the distant parties share a common reference frame. In practice, however, establishing and maintaining a good alignment between distant observers is rarely a trivial issue, which may significantly restrain the implementation of long-distance quantum communication protocols. Here we propose simple QKD protocols that do not require the parties to share any reference frame, and study their security and feasibility in both the usual device-dependent (DD) case—in which the two parties use well characterized measurement devices—as well as in the device-independent (DI) case—in which the measurement devices can be untrusted, and the security relies on the violation of a Bell inequality. To illustrate the practical relevance of these ideas, we present a proof-of-principle demonstration of our protocols using polarization entangled photons distributed over a coiled 10-km long optical fiber. We consider two situations, in which either the fiber spool's polarization transformation freely drifts, or randomly chosen polarization transformations are applied. The correlations obtained from measurements allow, with high probability, to generate positive asymptotic secret key rates in both the DD and DI scenarios (under the fair-sampling assumption for the latter case). (paper)

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

International Nuclear Information System (INIS)

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. (paper)

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.

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

Science.gov (United States)

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

2015-12-15

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

Investigation on Reference Frames and Time Systems in Multi-GNSS

Directory of Open Access Journals (Sweden)

Luca Nicolini

2018-01-01

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

Technical Note: Modification of the standard gain correction algorithm to compensate for the number of used reference flat frames in detector performance studies

International Nuclear Information System (INIS)

Konstantinidis, Anastasios C.; Olivo, Alessandro; Speller, Robert D.

2011-01-01

Purpose: The x-ray performance evaluation of digital x-ray detectors is based on the calculation of the modulation transfer function (MTF), the noise power spectrum (NPS), and the resultant detective quantum efficiency (DQE). The flat images used for the extraction of the NPS should not contain any fixed pattern noise (FPN) to avoid contamination from nonstochastic processes. The ''gold standard'' method used for the reduction of the FPN (i.e., the different gain between pixels) in linear x-ray detectors is based on normalization with an average reference flat-field. However, the noise in the corrected image depends on the number of flat frames used for the average flat image. The aim of this study is to modify the standard gain correction algorithm to make it independent on the used reference flat frames. Methods: Many publications suggest the use of 10-16 reference flat frames, while other studies use higher numbers (e.g., 48 frames) to reduce the propagated noise from the average flat image. This study quantifies experimentally the effect of the number of used reference flat frames on the NPS and DQE values and appropriately modifies the gain correction algorithm to compensate for this effect. Results: It is shown that using the suggested gain correction algorithm a minimum number of reference flat frames (i.e., down to one frame) can be used to eliminate the FPN from the raw flat image. This saves computer memory and time during the x-ray performance evaluation. Conclusions: The authors show that the method presented in the study (a) leads to the maximum DQE value that one would have by using the conventional method and very large number of frames and (b) has been compared to an independent gain correction method based on the subtraction of flat-field images, leading to identical DQE values. They believe this provides robust validation of the proposed method.

Phase-encoded measurement device independent quantum key distribution without a shared reference frame

Science.gov (United States)

Zhuo-Dan, Zhu; Shang-Hong, Zhao; Chen, Dong; Ying, Sun

2018-07-01

In this paper, a phase-encoded measurement device independent quantum key distribution (MDI-QKD) protocol without a shared reference frame is presented, which can generate secure keys between two parties while the quantum channel or interferometer introduces an unknown and slowly time-varying phase. The corresponding secret key rate and single photons bit error rate is analysed, respectively, with single photons source (SPS) and weak coherent source (WCS), taking finite-key analysis into account. The numerical simulations show that the modified phase-encoded MDI-QKD protocol has apparent superiority both in maximal secure transmission distance and key generation rate while possessing the improved robustness and practical security in the high-speed case. Moreover, the rejection of the frame-calibrating part will intrinsically reduce the consumption of resources as well as the potential security flaws of practical MDI-QKD systems.

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

OpenAIRE

Dechamps, Xavier; Hein, Stefan

2016-01-01

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

A reference Pelton turbine - High speed visualization in the rotating frame

Science.gov (United States)

Solemslie, Bjørn W.; Dahlhaug, Ole G.

2016-11-01

To enable a detailed study the flow mechanisms effecting the flow within the reference Pelton runner designed at the Waterpower Laboratory (NTNLT) a flow visualization system has been developed. The system enables high speed filming of the hydraulic surface of a single bucket in the rotating frame of reference. It is built with an angular borescopes adapter entering the turbine along the rotational axis and a borescope embedded within a bucket. A stationary high speed camera located outside the turbine housing has been connected to the optical arrangement by a non-contact coupling. The view point of the system includes the whole hydraulic surface of one half of a bucket. The system has been designed to minimize the amount of vibrations and to ensure that the vibrations felt by the borescope are the same as those affecting the camera. The preliminary results captured with the system are promising and enable a detailed study of the flow within the turbine.

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

Science.gov (United States)

Hill, D

1977-01-01

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

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...

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

A Novel Real-Time Reference Key Frame Scan Matching Method

Directory of Open Access Journals (Sweden)

Haytham Mohamed

2017-05-01

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

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

Science.gov (United States)

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

2017-11-01

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

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

Science.gov (United States)

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

2010-12-01

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

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...

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...

Quantum frames

Science.gov (United States)

Brown, Matthew J.

2014-02-01

The framework of quantum frames can help unravel some of the interpretive difficulties i the foundation of quantum mechanics. In this paper, I begin by tracing the origins of this concept in Bohr's discussion of quantum theory and his theory of complementarity. Engaging with various interpreters and followers of Bohr, I argue that the correct account of quantum frames must be extended beyond literal space-time reference frames to frames defined by relations between a quantum system and the exosystem or external physical frame, of which measurement contexts are a particularly important example. This approach provides superior solutions to key EPR-type measurement and locality paradoxes.

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

Celestial Seasonings: Astronomy and Rock Art in the American Southwest

Science.gov (United States)

Krupp, E. C.

1994-12-01

Astronomical interpretations of prehistoric rock art have played a significant part in the development of modern archaeoastronomy since 1975, when interest was renewed in the possibility that the Crab supernova explosion of 1054 A.D. was represented in rock art of the American Southwest. (This hypothesis was actually first formulated in 1955.) In the last two decades, a variety of astronomical functions for rock art have been proposed and investigated. These include representation of specific historical celestial events, symbolic representation of elements of celestial myths, star maps, markers for astronomical observing stations markers for celestially tempered shrines, images intended to invoke and exploit cosmo-magical power, seasonally significant light-and-shadow displays. Examples of astronomical connotations in prehistoric rock art from the Southwest and California illustrate the necessity of understanding the culture in any attempt to understand its astronomy.

Structured perceptual input imposes an egocentric frame of reference-pointing, imagery, and spatial self-consciousness.

Science.gov (United States)

Marcel, Anthony; Dobel, Christian

2005-01-01

Perceptual input imposes and maintains an egocentric frame of reference, which enables orientation. When blindfolded, people tended to mistake the assumed intrinsic axes of symmetry of their immediate environment (a room) for their own egocentric relation to features of the room. When asked to point to the door and window, known to be at mid-points of facing (or adjacent) walls, they pointed with their arms at 180 degrees (or 90 degrees) angles, irrespective of where they thought they were in the room. People did the same when requested to imagine the situation. They justified their responses (inappropriately) by logical necessity or a structural description of the room rather than (appropriately) by relative location of themselves and the reference points. In eight experiments, we explored the effect on this in perception and imagery of: perceptual input (without perceptibility of the target reference points); imaging oneself versus another person; aids to explicit spatial self-consciousness; order of questions about self-location; and the relation of targets to the axes of symmetry of the room. The results indicate that, if one is deprived of structured perceptual input, as well as losing one's bearings, (a) one is likely to lose one's egocentric frame of reference itself, and (b) instead of pointing to reference points, one demonstrates their structural relation by adopting the intrinsic axes of the environment as one's own. This is prevented by providing noninformative perceptual input or by inducing subjects to imagine themselves from the outside, which makes explicit the fact of their being located relative to the world. The role of perceptual contact with a structured world is discussed in relation to sensory deprivation and imagery, appeal is made to Gibson's theory of joint egoreception and exteroception, and the data are related to recent theories of spatial memory and navigation.

Greenberger-Horne-Zeilinger-like proof of Bell's theorem involving observers who do not share a reference frame

International Nuclear Information System (INIS)

Cabello, Adan

2003-01-01

Vaidman described how a team of three players, each of them isolated in a remote booth, could use a three-qubit Greenberger-Horne-Zeilinger state to always win a game which would be impossible to always win without quantum resources. However, Vaidman's method requires all three players to share a common reference frame; it does not work if the adversary is allowed to disorientate one player. Here we show how to always win the game, even if the players do not share any reference frame. The introduced method uses a 12-qubit state which is invariant under any transformation R a xR b xR c (where R a =U a xU a xU a xU a , where U j is a unitary operation on a single qubit) and requires only single-qubit measurements. A number of further applications of this 12-qubit state are described

Navigation accuracy comparing non-covered frame and use of plastic sterile drapes to cover the reference frame in 3D acquisition.

Science.gov (United States)

Corenman, Donald S; Strauch, Eric L; Dornan, Grant J; Otterstrom, Eric; Zalepa King, Lisa

2017-09-01

Advancements in surgical navigation technology coupled with 3-dimensional (3D) radiographic data have significantly enhanced the accuracy and efficiency of spinal fusion implant placement. Increased usage of such technology has led to rising concerns regarding maintenance of the sterile field, as makeshift drape systems are fraught with breaches thus presenting increased risk of surgical site infections (SSIs). A clinical need exists for a sterile draping solution with these techniques. Our objective was to quantify expected accuracy error associated with 2MM and 4MM thickness Sterile-Z Patient Drape ® using Medtronic O-Arm ® Surgical Imaging with StealthStation ® S7 ® Navigation System. Camera distance to reference frame was investigated for contribution to accuracy error. A testing jig was placed on the radiolucent table and the Medtronic passive reference frame was attached to jig. The StealthStation ® S7 ® navigation camera was placed at various distances from testing jig and the geometry error of reference frame was captured for three different drape configurations: no drape, 2MM drape and 4MM drape. The O-Arm ® gantry location and StealthStation ® S7 ® camera position was maintained and seven 3D acquisitions for each of drape configurations were measured. Data was analyzed by a two-factor analysis of variance (ANOVA) and Bonferroni comparisons were used to assess the independent effects of camera angle and drape on accuracy error. Median (and maximum) measurement accuracy error was higher for the 2MM than for the 4MM drape for each camera distance. The most extreme error observed (4.6 mm) occurred when using the 2MM and the 'far' camera distance. The 4MM drape was found to induce an accuracy error of 0.11 mm (95% confidence interval, 0.06-0.15; P<0.001) relative to the no drape testing, regardless of camera distance. Medium camera distance produced lower accuracy error than either the close (additional 0.08 mm error; 95% CI, 0-0.15; P=0.035) or far

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. Copyright © 2012 Elsevier B.V. All rights reserved.

Frame by Frame II: A Filmography of the African American Image, 1978-1994.

Science.gov (United States)

Klotman, Phyllis R.; Gibson, Gloria J.

A reference guide on African American film professionals, this book is a companion volume to the earlier "Frame by Frame I." It focuses on giving credit to African Americans who have contributed their talents to a film industry that has scarcely recognized their contributions, building on the aforementioned "Frame by Frame I,"…

The Role of Celestial Compass Information in Cataglyphis Ants during Learning Walks and for Neuroplasticity in the Central Complex and Mushroom Bodies.

Science.gov (United States)

Grob, Robin; Fleischmann, Pauline N; Grübel, Kornelia; Wehner, Rüdiger; Rössler, Wolfgang

2017-01-01

Central place foragers are faced with the challenge to learn the position of their nest entrance in its surroundings, in order to find their way back home every time they go out to search for food. To acquire navigational information at the beginning of their foraging career, Cataglyphis noda performs learning walks during the transition from interior worker to forager. These small loops around the nest entrance are repeatedly interrupted by strikingly accurate back turns during which the ants stop and precisely gaze back to the nest entrance-presumably to learn the landmark panorama of the nest surroundings. However, as at this point the complete navigational toolkit is not yet available, the ants are in need of a reference system for the compass component of the path integrator to align their nest entrance-directed gazes. In order to find this directional reference system, we systematically manipulated the skylight information received by ants during learning walks in their natural habitat, as it has been previously suggested that the celestial compass, as part of the path integrator, might provide such a reference system. High-speed video analyses of distinct learning walk elements revealed that even exclusion from the skylight polarization pattern, UV-light spectrum and the position of the sun did not alter the accuracy of the look back to the nest behavior. We therefore conclude that C. noda uses a different reference system to initially align their gaze directions. However, a comparison of neuroanatomical changes in the central complex and the mushroom bodies before and after learning walks revealed that exposure to UV light together with a naturally changing polarization pattern was essential to induce neuroplasticity in these high-order sensory integration centers of the ant brain. This suggests a crucial role of celestial information, in particular a changing polarization pattern, in initially calibrating the celestial compass system.

The Role of Celestial Compass Information in Cataglyphis Ants during Learning Walks and for Neuroplasticity in the Central Complex and Mushroom Bodies

Directory of Open Access Journals (Sweden)

Robin Grob

2017-11-01

Full Text Available Central place foragers are faced with the challenge to learn the position of their nest entrance in its surroundings, in order to find their way back home every time they go out to search for food. To acquire navigational information at the beginning of their foraging career, Cataglyphis noda performs learning walks during the transition from interior worker to forager. These small loops around the nest entrance are repeatedly interrupted by strikingly accurate back turns during which the ants stop and precisely gaze back to the nest entrance—presumably to learn the landmark panorama of the nest surroundings. However, as at this point the complete navigational toolkit is not yet available, the ants are in need of a reference system for the compass component of the path integrator to align their nest entrance-directed gazes. In order to find this directional reference system, we systematically manipulated the skylight information received by ants during learning walks in their natural habitat, as it has been previously suggested that the celestial compass, as part of the path integrator, might provide such a reference system. High-speed video analyses of distinct learning walk elements revealed that even exclusion from the skylight polarization pattern, UV-light spectrum and the position of the sun did not alter the accuracy of the look back to the nest behavior. We therefore conclude that C. noda uses a different reference system to initially align their gaze directions. However, a comparison of neuroanatomical changes in the central complex and the mushroom bodies before and after learning walks revealed that exposure to UV light together with a naturally changing polarization pattern was essential to induce neuroplasticity in these high-order sensory integration centers of the ant brain. This suggests a crucial role of celestial information, in particular a changing polarization pattern, in initially calibrating the celestial compass system.

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. *

Impact of uncertain reference-frame motions in plate kinematic reconstructions

DEFF Research Database (Denmark)

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...... – 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...

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.

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.

Analysis and controller design for stand-alone VSIs in synchronous reference frame

DEFF Research Database (Denmark)

Ramezani, Malek; Li, Shuhui; Golestan, Saeed

2017-01-01

-by-step graphical analysis and design approach for a three-phase stand-alone VSI system in the dq reference frame, which provides a clear systematic decoupling process to design the inner- and outer-loop current and voltage controllers, respectively. The closed-loop d- and q-axis output impedances of the stand......-alone VSI system by considering the coupling effects between axes are also formulated, modelled, and evaluated. The study investigates how the decoupling and compensating terms added in the current and voltage controllers affect the dynamic performance and output dq impedances of the VSI system. Simulation...... and hardware results verify the effectiveness of the graphic design and analysis strategy....

Celestial mechanics the waltz of the planets

CERN Document Server

Celletti, Alessandra

2007-01-01

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

The irreducible needs of children for development: a frame of reference to health care

Directory of Open Access Journals (Sweden)

Maria De La Ó Ramallo Veríssimo

2018-03-01

Full Text Available ABSTRACT A comprehensive health care to children implies in caring for their development, by perceiving the needs based on a suitable reference to children’s specificities. This theoretical study aimed to analyze the “irreducible needs of children” frame of reference, based on a child development theory. We performed a comparative analysis between the contents of children’s irreducible needs and the components of the Bioecological Theory of Human Development. An extensive correspondence was verified among the components of the Bioecological Theory and the following essential needs: ongoing nurturing relationships; experiences tailored to individual differences; developmentally appropriate experiences; limit setting, structure and expectations; stable, supportive communities and cultural continuity. The need for physical protection, safety, and regulation is not explicit in the elements of the theory, although it is also verified in their definitions. We concluded that the irreducible needs’ reference can support nurses in health care and in child development promotion.

Molecular frame and recoil frame angular distributions in dissociative photoionization of small molecules

International Nuclear Information System (INIS)

Lucchese, R R; Carey, R; Elkharrat, C; Houver, J C; Dowek, D

2008-01-01

Photoelectron angular distributions in the dipole approximation can be written with respect to several different reference frames. A brief review of the molecular frame and recoil frame are given. Experimentally, one approach for obtaining such angular distributions is through angle-resolved coincidence measurements of dissociative ionization. If the system dissociates into two heavy fragments, then the recoil frame angular distribution can be measured. Computed molecular frame and recoil frame photoelectron angular distributions are compared to experimental data for the Cl 2p ionization of CH 3 Cl.

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

Science.gov (United States)

Lim, Sun-Young; Chang, Sung-Ok

2018-01-01

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

A celestial assisted INS initialization method for lunar explorers.

Science.gov (United States)

Ning, Xiaolin; Wang, Longhua; Wu, Weiren; Fang, Jiancheng

2011-01-01

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.

Numerical Analysis of a Rotating Detonation Engine in the Relative Reference Frame

Science.gov (United States)

Paxson, Daniel E.

2014-01-01

A two-dimensional, computational fluid dynamic (CFD) simulation of a semi-idealized rotating detonation engine (RDE) is described. The simulation operates in the detonation frame of reference and utilizes a relatively coarse grid such that only the essential primary flow field structure is captured. This construction yields rapidly converging, steady solutions. Results from the simulation are compared to those from a more complex and refined code, and found to be in reasonable agreement. The performance impacts of several RDE design parameters are then examined. Finally, for a particular RDE configuration, it is found that direct performance comparison can be made with a straight-tube pulse detonation engine (PDE). Results show that they are essentially equivalent.

When Students Doubt Their Teachers' Diagnostic Competence: Moderation in the Internal/External Frame of Reference Model

Science.gov (United States)

Zimmermann, Friederike; Möller, Jens; Köller, Olaf

2018-01-01

The internal/external frame of reference model (I/E model) posits that individuals' achievement-related self-concepts are formed through social comparisons (e.g., self vs. peers) within academic domains and dimensional comparisons (e.g., math vs. verbal) between distinct domains. A large body of research has supported the theorized pattern of…

Demonstration of free-space reference frame independent quantum key distribution

International Nuclear Information System (INIS)

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

2013-01-01

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

Adventures in Celestial Mechanics

CERN Document Server

Szebehely, Victor G

1998-01-01

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

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

DEFF Research Database (Denmark)

Liu, Yi; Xu, Wei; Ke, Longzhang

2017-01-01

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

Comprehensive synchronous reference frame discrete-time modelling of a grid-connected PV for fast DC-side voltage control

NARCIS (Netherlands)

Almeida, P.M.; Barbosa, P.G.; Duarte, J.L.; Ribeiro, P.F.

2017-01-01

This paper presents a novel comprehensive discrete-time model of a three-phase single stage grid-connected photovoltaic generation system. The detailed model is carried out on synchronous reference frame. It is shown that both converter's AC and DC-side discrete time model differs from the

Geodetic precession or dragging of inertial frames?

International Nuclear Information System (INIS)

Ashby, N.; Shahid-Saless, B.

1990-01-01

In metric theories of gravity the principle of general covariance allows one to describe phenomena by means of any convenient choice of coordinate system. In this paper it is shown that in an appropriately chosen coordinate system, geodetic precession of a gyroscope orbiting a spherically symmetric, spinning mass can be recast as a Lense-Thirring frame-dragging effect without invoking spatial curvature. The origin of this reference frame moves around the source but the frame axes point in fixed directions. The drag can be interpreted to arise from the orbital angular momentum of the source around the origin of the reference frame. In this reference frame the effects of geodetic precession and Lense-Thirring drag due to intrinsic angular momentum of the source have the same origin, namely, gravitomagnetism

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.

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...

Urgensi Penerapan Celestial Management Bagi Sumber Daya Manusia Di Bank Syariah

Directory of Open Access Journals (Sweden)

Trimulato Trimulato

2016-05-01

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

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

International Nuclear Information System (INIS)

Richter-Was, E.; Was, Z.

2017-01-01

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 → lν decays in the lepton-pair rest-frame. The vector nature of the intermediate state imposes that distributions are to a good precision described by spherical harmonics of at most second order. We argue, that contrary to general belief often expressed in the literature, the full set of angular coefficients can be measured experimentally, despite the presence of escaping detection neutrino in the final state. There is thus no principle difference with respect to the phenomenology of the Z/γ → l"+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. (orig.)

New Methods of Celestial Mechanics

CERN Document Server

Vrbik, Jan

2010-01-01

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

Classical relativistic ideal gas in thermodynamic equilibrium in a uniformly accelerated reference frame

International Nuclear Information System (INIS)

Louis-Martinez, Domingo J

2011-01-01

A classical (non-quantum-mechanical) relativistic ideal gas in thermodynamic equilibrium in a uniformly accelerated frame of reference is studied using Gibbs's microcanonical and grand canonical formulations of statistical mechanics. Using these methods explicit expressions for the particle, energy and entropy density distributions are obtained, which are found to be in agreement with the well-known results of the relativistic formulation of Boltzmann's kinetic theory. Explicit expressions for the total entropy, total energy and rest mass of the gas are obtained. The position of the center of mass of the gas in equilibrium is found. The non-relativistic and ultrarelativistic approximations are also considered. The phase space volume of the system is calculated explicitly in the ultrarelativistic approximation.

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

Science.gov (United States)

Raposo, Pedro M. P.

2018-01-01

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

Influence of celestial parameters on Mercury's perihelion shift

Czech Academy of Sciences Publication Activity Database

Křížek, Michal

2017-01-01

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

Influence of celestial parameters on Mercury's perihelion shift

Czech Academy of Sciences Publication Activity Database

Křížek, Michal

2017-01-01

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

Supplier-induced demand as strategic framing

OpenAIRE

De Jaegher, K.J.M.

2010-01-01

This paper develops a model of supplier-induced demand as strategic framing where the patient has reference-dependent references, and the physician can persuade the patient to buy a treatment by affecting the patient’s reference point. In the main result, the patient is assumed to have a constant rate of risk aversion (lovingness) in the gain (loss) region. Two scenarios are treated. In the cure scenario, the physician wants to frame the patient’s decision problem such that he prefers to buy ...

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

Science.gov (United States)

Popova, E.

2017-12-01

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

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

Science.gov (United States)

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

2010-09-01

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

Polarization Patterns of Transmitted Celestial Light under Wavy Water Surfaces

Directory of Open Access Journals (Sweden)

Guanhua Zhou

2017-03-01

Full Text Available This paper presents a model to describe the polarization patterns of celestial light, which includes sunlight and skylight, when refracted by wavy water surfaces. The polarization patterns and intensity distribution of refracted light through the wave water surface were calculated. The model was validated by underwater experimental measurements. The experimental and theoretical values agree well qualitatively. This work provides a quantitative description of the repolarization and transmittance of celestial light transmitted through wave water surfaces. The effects of wind speed and incident sources on the underwater refraction polarization patterns are discussed. Scattering skylight dominates the polarization patterns while direct solar light is the dominant source of the intensity of the underwater light field. Wind speed has an influence on disturbing the patterns under water.

UBVRI PHOTOMETRIC STANDARD STARS AROUND THE CELESTIAL EQUATOR: UPDATES AND ADDITIONS

International Nuclear Information System (INIS)

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.

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…

Polarization transition between sunlit and moonlit skies with possible implications for animal orientation and Viking navigation: anomalous celestial twilight polarization at partial moon.

Science.gov (United States)

Barta, András; Farkas, Alexandra; Száz, Dénes; Egri, Ádám; Barta, Pál; Kovács, József; Csák, Balázs; Jankovics, István; Szabó, Gyula; Horváth, Gábor

2014-08-10

Using full-sky imaging polarimetry, we measured the celestial distribution of polarization during sunset and sunrise at partial (78% and 72%) and full (100%) moon in the red (650 nm), green (550 nm), and blue (450 nm) parts of the spectrum. We investigated the temporal change of the patterns of degree p and angle α of linear polarization of sunlit and moonlit skies at dusk and dawn. We describe here the position change of the neutral points of sky polarization, and present video clips about the celestial polarization transition at moonlit twilight. We found that at partial moon and at a medium latitude (47° 15.481' N) during this transition there is a relatively short (10-20 min) period when (i) the maximum of p of skylight decreases, and (ii) from the celestial α pattern neither the solar-antisolar nor the lunar-antilunar meridian can be unambiguously determined. These meridians can serve as reference directions of animal orientation and Viking navigation based on sky polarization. The possible influence of these atmospheric optical phenomena during the polarization transition between sunlit and moonlit skies on the orientation of polarization-sensitive crepuscular/nocturnal animals and the hypothesized navigation of sunstone-aided Viking seafarers is discussed.

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-06-15

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

Hubble peers inside a celestial geode

Science.gov (United States)

2004-08-01

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

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

[The celestial phenomena in A. Dürer's engraving Melancholia I].

Science.gov (United States)

Weitzel, Hans

2009-01-01

The celestial body of Dürer's engraving Melencolia I is connected with his painting of a meteor, the Raveningham-painting; it is shown that the origin of this painting owns to the impact of the meteor of Ensisheim in 1492. Until now the celestial body, the balance, and the magic square are nearly consistently interpreted as the planet Saturn, the zodiac sign Libra, and the planet Jupiter, and the melancholy woman is subject to these heavenly bodies. Consequently, neoplatonic astrology has been the main focus of the engraving; including the rainbow, the engraving has also been interpreted biblically. The present paper, however, places emphasis on problems of the geometry as the reason of melancholy. Any astronomical meaning of the configuration of the numbers of the magic square is discarded.

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.

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.

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

Science.gov (United States)

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

2014-01-01

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

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

Dragging of inertial frames.

Science.gov (United States)

Ciufolini, Ignazio

2007-09-06

The origin of inertia has intrigued scientists and philosophers for centuries. Inertial frames of reference permeate our daily life. The inertial and centrifugal forces, such as the pull and push that we feel when our vehicle accelerates, brakes and turns, arise because of changes in velocity relative to uniformly moving inertial frames. A classical interpretation ascribed these forces to acceleration relative to some absolute frame independent of the cosmological matter, whereas an opposite view related them to acceleration relative to all the masses and 'fixed stars' in the Universe. An echo and partial realization of the latter idea can be found in Einstein's general theory of relativity, which predicts that a spinning mass will 'drag' inertial frames along with it. Here I review the recent measurements of frame dragging using satellites orbiting Earth.

A Giant with Feet of Clay : A First Law and Economics Analysis of the Draft Common Frame of Reference (DCFR)

NARCIS (Netherlands)

Chirico, F.; van Damme, E.E.C.; Larouche, P.

2010-01-01

This paper contains the conclusions from the work of the Economic Impact Group (EIG), a part of the CoPECL Network of Excellence funded by the EU to prepare a Draft Common Frame of Reference (DCFR). Part 1 revisits basic principles which are central to the work of the whole group. For one, contract

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...

Harnessing Wind Power in Moving Reference Frames with Application to Vehicles

Science.gov (United States)

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

2017-11-01

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

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

Directory of Open Access Journals (Sweden)

Nana Kanzaki

2018-02-01

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

The Effect of Motion Analysis Activities in a Video-Based Laboratory in Students' Understanding of Position, Velocity and Frames of Reference

Science.gov (United States)

Koleza, Eugenia; Pappas, John

2008-01-01

In this article, we present the results of a qualitative research project on the effect of motion analysis activities in a Video-Based Laboratory (VBL) on students' understanding of position, velocity and frames of reference. The participants in our research were 48 pre-service teachers enrolled in Education Departments with no previous strong…

Electrodynamics in Arbitrary Reference Frames and in Arbitrary Material Media

International Nuclear Information System (INIS)

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

1999-01-01

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

Regular Formal Evaluation Sessions are Effective as Frame-of-Reference Training for Faculty Evaluators of Clerkship Medical Students.

Science.gov (United States)

Hemmer, Paul A; Dadekian, Gregory A; Terndrup, Christopher; Pangaro, Louis N; Weisbrod, Allison B; Corriere, Mark D; Rodriguez, Rechell; Short, Patricia; Kelly, William F

2015-09-01

Face-to-face formal evaluation sessions between clerkship directors and faculty can facilitate the collection of trainee performance data and provide frame-of-reference training for faculty. We hypothesized that ambulatory faculty who attended evaluation sessions at least once in an academic year (attendees) would use the Reporter-Interpreter-Manager/Educator (RIME) terminology more appropriately than faculty who did not attend evaluation sessions (non-attendees). Investigators conducted a retrospective cohort study using the narrative assessments of ambulatory internal medicine clerkship students during the 2008-2009 academic year. The study included assessments of 49 clerkship medical students, which comprised 293 individual teacher narratives. Single-teacher written and transcribed verbal comments about student performance were masked and reviewed by a panel of experts who, by consensus, (1) determined whether RIME was used, (2) counted the number of RIME utterances, and (3) assigned a grade based on the comments. Analysis included descriptive statistics and Pearson correlation coefficients. The authors reviewed 293 individual teacher narratives regarding the performance of 49 students. Attendees explicitly used RIME more frequently than non-attendees (69.8 vs. 40.4 %; p sessions used RIME terminology more frequently and provided more accurate grade recommendations than teachers who did not attend. Formal evaluation sessions may provide frame-of-reference training for the RIME framework, a method that improves the validity and reliability of workplace assessment.

Reynolds Stress Closure for Inertial Frames and Rotating Frames

Science.gov (United States)

Petty, Charles; Benard, Andre

2017-11-01

In a rotating frame-of-reference, the Coriolis acceleration and the mean vorticity field have a profound impact on the redistribution of kinetic energy among the three components of the fluctuating velocity. Consequently, the normalized Reynolds (NR) stress is not objective. Furthermore, because the Reynolds stress is defined as an ensemble average of a product of fluctuating velocity vector fields, its eigenvalues must be non-negative for all turbulent flows. These fundamental properties (realizability and non-objectivity) of the NR-stress cannot be compromised in computational fluid dynamic (CFD) simulations of turbulent flows in either inertial frames or in rotating frames. The recently developed universal realizable anisotropic prestress (URAPS) closure for the NR-stress depends explicitly on the local mean velocity gradient and the Coriolis operator. The URAPS-closure is a significant paradigm shift from turbulent closure models that assume that dyadic-valued operators associated with turbulent fluctuations are objective.

Tree-level gluon amplitudes on the celestial sphere

Science.gov (United States)

Schreiber, Anders Ø.; Volovich, Anastasia; Zlotnikov, Michael

2018-06-01

Pasterski, Shao and Strominger have recently proposed that massless scattering amplitudes can be mapped to correlators on the celestial sphere at infinity via a Mellin transform. We apply this prescription to arbitrary n-point tree-level gluon amplitudes. The Mellin transforms of MHV amplitudes are given by generalized hypergeometric functions on the Grassmannian Gr (4 , n), while generic non-MHV amplitudes are given by more complicated Gelfand A-hypergeometric functions.

Supplier-induced demand as strategic framing

NARCIS (Netherlands)

De Jaegher, K.J.M.

2010-01-01

This paper develops a model of supplier-induced demand as strategic framing where the patient has reference-dependent references, and the physician can persuade the patient to buy a treatment by affecting the patient’s reference point. In the main result, the patient is assumed to have a constant

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

2016-01-01

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…

Allocentrically implied target locations are updated in an eye-centred reference frame.

Science.gov (United States)

Thompson, Aidan A; Glover, Christopher V; Henriques, Denise Y P

2012-04-18

When reaching to remembered target locations following an intervening eye movement a systematic pattern of error is found indicating eye-centred updating of visuospatial memory. Here we investigated if implicit targets, defined only by allocentric visual cues, are also updated in an eye-centred reference frame as explicit targets are. Participants viewed vertical bars separated by varying distances, and horizontal lines of equivalently varying lengths, implying a "target" location at the midpoint of the stimulus. After determining the implied "target" location from only the allocentric stimuli provided, participants saccaded to an eccentric location, and reached to the remembered "target" location. Irrespective of the type of stimulus reaching errors to these implicit targets are gaze-dependent, and do not differ from those found when reaching to remembered explicit targets. Implicit target locations are coded and updated as a function of relative gaze direction with respect to those implied locations just as explicit targets are, even though no target is specifically represented. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

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...

Bound states for a neutral particle analogous to a quantum dot induced by the non-inertial effects of the Fermi-Walker reference frame

International Nuclear Information System (INIS)

Bakke, Knut

2010-01-01

We study the appearance of bound states analogous to a quantum dot, proposed by Tan and Inkson (1996) , in the non-relativistic quantum dynamics of a neutral particle with permanent magnetic dipole moment induced by the non-inertial effects of the Fermi-Walker reference frame.

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

Directory of Open Access Journals (Sweden)

Karthikrjan Senthilnathan

2018-02-01

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

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

Frame-based safety analysis approach for decision-based errors

International Nuclear Information System (INIS)

Fan, Chin-Feng; Yihb, Swu

1997-01-01

A frame-based approach is proposed to analyze decision-based errors made by automatic controllers or human operators due to erroneous reference frames. An integrated framework, Two Frame Model (TFM), is first proposed to model the dynamic interaction between the physical process and the decision-making process. Two important issues, consistency and competing processes, are raised. Consistency between the physical and logic frames makes a TFM-based system work properly. Loss of consistency refers to the failure mode that the logic frame does not accurately reflect the state of the controlled processes. Once such failure occurs, hazards may arise. Among potential hazards, the competing effect between the controller and the controlled process is the most severe one, which may jeopardize a defense-in-depth design. When the logic and physical frames are inconsistent, conventional safety analysis techniques are inadequate. We propose Frame-based Fault Tree; Analysis (FFTA) and Frame-based Event Tree Analysis (FETA) under TFM to deduce the context for decision errors and to separately generate the evolution of the logical frame as opposed to that of the physical frame. This multi-dimensional analysis approach, different from the conventional correctness-centred approach, provides a panoramic view in scenario generation. Case studies using the proposed techniques are also given to demonstrate their usage and feasibility

[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.

Quotation and Framing

DEFF Research Database (Denmark)

Petersen, Nils Holger

2010-01-01

. In Black Angels the composer – among other well-known pieces of music – quotes the medieval dies irae sequence and the second movement of Schubert’s string quartet in D minor (D. 810). The musical and intermedial references are framed with striking modernistic sounds exploring instrumental possibilities...

A Stationary Reference Frame Grid Synchronization System for Three-Phase Grid-Connected Power Converters Under Adverse Grid Conditions

DEFF Research Database (Denmark)

Rodríguez, P.; Luna, A.; Muñoz-Aguilar, R. S.

2012-01-01

synchronization method for three-phase three-wire networks, namely dual second-order generalized integrator (SOGI) frequency-locked loop. The method is based on two adaptive filters, implemented by using a SOGI on the stationary αβ reference frame, and it is able to perform an excellent estimation......Grid synchronization algorithms are of great importance in the control of grid-connected power converters, as fast and accurate detection of the grid voltage parameters is crucial in order to implement stable control strategies under generic grid conditions. This paper presents a new grid...

Changing climate, changing frames

International Nuclear Information System (INIS)

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

2013-01-01

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

Infrared radiation scene generation of stars and planets in celestial background

Science.gov (United States)

Guo, Feng; Hong, Yaohui; Xu, Xiaojian

2014-10-01

An infrared (IR) radiation generation model of stars and planets in celestial background is proposed in this paper. Cohen's spectral template1 is modified for high spectral resolution and accuracy. Based on the improved spectral template for stars and the blackbody assumption for planets, an IR radiation model is developed which is able to generate the celestial IR background for stars and planets appearing in sensor's field of view (FOV) for specified observing date and time, location, viewpoint and spectral band over 1.2μm ~ 35μm. In the current model, the initial locations of stars are calculated based on midcourse space experiment (MSX) IR astronomical catalogue (MSX-IRAC) 2 , while the initial locations of planets are calculated using secular variations of the planetary orbits (VSOP) theory. Simulation results show that the new IR radiation model has higher resolution and accuracy than common model.

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

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...

A New Way of Controlling Parallel-Connected Inverters by Using Synchronous-Reference-Frame Virtual Impedance Loop

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....

Work and Inertial Frames

Science.gov (United States)

Kaufman, Richard

2017-12-01

A fairly recent paper resolves a large discrepancy in the internal energy utilized to fire a cannon as calculated by two inertial observers. Earth and its small reaction velocity must be considered in the system so that the change in kinetic energy is calculated correctly. This paper uses a car in a similar scenario, but considers the work done by forces acting over distances. An analysis of the system must include all energy interactions, including the work done on the car and especially the (negative) work done on Earth in a moving reference frame. This shows the importance of considering the force on Earth and the distance Earth travels. For calculation of work in inertial reference frames, the center of mass perspective is shown to be useful. We also consider the energy requirements to efficiently accelerate a mass among interacting masses.

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

Science.gov (United States)

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

2010-01-01

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

Technological Frame Incongruence, Diffusion, and Noncompliance

Science.gov (United States)

Sobreperez, Polly

The technological frames of reference strand of social shaping of technology theory is used to overlay the issues arising from a case study looking at noncompliance with information systems. A recent review of the theory suggests that although frame content is often addressed, frame structure, the process of framing, and the characteristics and outcomes of frames are largely overlooked. This paper attempts to address this shortfall by applying the indicators identified by case study research to the frames of different groups and using them to highlight differing perceptions and attitudes. In this way, the author suggests that issues surrounding noncompliance should not be dismissed as resistance but instead should be further studied by managers and developers, leading to accommodation of differing views. Further examination of frame incongruence reveals dependence on inefficient or ineffective organizational situations and thus these indicators can be useful in future studies to identify and address procedural, acceptance and cultural issues leading to acts of noncompliance.

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

Science.gov (United States)

Cerqueglini, Letizia

2015-09-01

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

The significance of the Sun, Moon and celestial bodies to societies in the Carpathian basin during the Bronze Age

Science.gov (United States)

Pásztor, Emília

2011-06-01

Celestial events often exerted a great or even decisive influence on the life of ancient communities. They may provide some of the foundations on which an understanding of the deeper meaning of mythologies, religious systems and even folk tales can be based. These influences are reflected and may be detected in the archaeological material as well. There is good evidence that celestial (especially solar and perhaps lunar) phenomena played a particularly important rôle in the worldview of prehistoric Europe. To reveal the social and ideational significance of concepts relating to the celestial bodies in the prehistory of the Carpathian Basin, complex investigations on orientations of houses and graves, prestige archaeological finds and iconography have been accomplished. The results indicate ideological and/or social changes, which developed into a likely organized ideological system in large part of Central Europe including the Carpathian Basin by the Late Bronze Age. It might also be the first period in prehistory when people became really interested in celestial phenomena.

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

Science.gov (United States)

Marsh, Herbert W.; Hau, Kit-Tai

2004-01-01

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

Frames and semi-frames

International Nuclear Information System (INIS)

Antoine, Jean-Pierre; Balazs, Peter

2011-01-01

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

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

International Nuclear Information System (INIS)

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

2002-01-01

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

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

Science.gov (United States)

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

2016-01-01

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

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

Science.gov (United States)

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

2018-04-01

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

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...

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

Science.gov (United States)

Anderson, T P

1975-03-01

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

Pseudo-set framing.

Science.gov (United States)

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

2017-10-01

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

Towards a poetics of the cinematographic frame

Directory of Open Access Journals (Sweden)

Des O'Rawe

2011-05-01

Full Text Available In delineating a poetics of the cinematographic frame, this essay presents a typology of framing styles, and demonstrates ways in which filmmakers use the frame as an expressive resource—and ways in which the frame uses them. The examples discussed are modernist in orientation, and each has a particular association with a city—its history, architecture, and cultural character. Although it is common practice to refer to various—especially, modernist—framing situations as instances of deframing, the essay also enquires into the problematic nature of this term, suggesting alternative visual and cinematographic contexts more amenable to the deconstructive implications of this term. As the boundaries between cinema and the other arts continue to converge and relations between frame, image, and screen become more complex, this essay offers a reassessment of some first principles of film language, especially the aesthetic integrity of the cinematographic frame.

The research of the coupled orbital-attitude controlled motion of celestial body in the neighborhood of the collinear libration point L1

Science.gov (United States)

Shmyrov, A.; Shmyrov, V.; Shymanchuk, D.

2017-10-01

This article considers the motion of a celestial body within the restricted three-body problem of the Sun-Earth system. The equations of controlled coupled attitude-orbit motion in the neighborhood of collinear libration point L1 are investigated. The translational orbital motion of a celestial body is described using Hill's equations of circular restricted three-body problem of the Sun-Earth system. Rotational orbital motion is described using Euler's dynamic equations and quaternion kinematic equation. We investigate the problem of stability of celestial body rotational orbital motion in relative equilibrium positions and stabilization of celestial body rotational orbital motion with proposed control laws in the neighborhood of collinear libration point L1. To study stabilization problem, Lyapunov function is constructed in the form of the sum of the kinetic energy and special "kinematic function" of the Rodriguez-Hamiltonian parameters. Numerical modeling of the controlled rotational motion of a celestial body at libration point L1 is carried out. The numerical characteristics of the control parameters and rotational motion are given.

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

Directory of Open Access Journals (Sweden)

V. M. Zyskin

2016-01-01

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

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.

Modeling laser wakefield accelerators in a Lorentz boosted frame

International Nuclear Information System (INIS)

Vay, J.-L.; Geddes, C.G.R.; Cormier-Michel, E.; Grote, D.P.

2010-01-01

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 accommodate 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.

Research on Optimization of Formula SAE Truss-Frame

Directory of Open Access Journals (Sweden)

Wang Yu

2017-01-01

Full Text Available The frame, as one of the basic components of a car, plays an important role of connecting components and withstanding various loads. The truss-frame is the commonest form of Formula SAE car in that it has many advantages, such as low cost, simple manufacture, high rigidity and high strength. The development of frame is reviewed. First, the key performance indicators and the mechanical state of the frame under different conditions are discussed. Second, a variety of optimization methods used in the design of frame are described. Finally, the test method of frame are introduced, with the experimental data and the finite element analysis of results being compared. Through analyzing and summarizing the development of the design, optimization and testing technology of the Formula SAE truss-frame, forecasting the future trends, the great theoretical reference is provided for the design and research of the follow-up frame.

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.

QUIKVIS- CELESTIAL TARGET AVAILABILITY INFORMATION

Science.gov (United States)

Petruzzo, C.

1994-01-01

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

How and Why to Do VLBI on GPS

Science.gov (United States)

Dickey, J. M.

2010-01-01

In order to establish the position of the center of mass of the Earth in the International Celestial Reference Frame, observations of the Global Positioning Satellite (GPS) constellation using the IVS network are important. With a good frame-tie between the coordinates of the IVS telescopes and nearby GPS receivers, plus a common local oscillator reference signal, it should be possible to observe and record simultaneously signals from the astrometric calibration sources and the GPS satellites. The standard IVS solution would give the atmospheric delay and clock offsets to use in analysis of the GPS data. Correlation of the GPS signals would then give accurate orbital parameters of the satellites in the ICRF reference frame, i.e., relative to the positions of the astrometric sources. This is particularly needed to determine motion of the center of mass of the earth along the rotation axis.

The purpose and coherence of the rules on good faith acquisition and acquisitive prescription in the Draft Common Frame of Reference: a tale of two gatekeepers

NARCIS (Netherlands)

Salomons, A.

2013-01-01

The drafters of Book VIII of the Draft Common Frame of Reference (DCFR) have consistently tried to formulate rules on the related topics of acquisitive prescription and good faith acquisition to further the underlying policy goals: where ordinary transfer has failed, good faith acquisition should

Mixed Frames and Risky Decision-Making.

Science.gov (United States)

Peng, Jiaxi; Zhang, Jiaxi; Sun, Hao; Zeng, Zhicong; Mai, Yuexia; Miao, Danmin

2017-01-01

By applying unitive vocabulary, "die" or "save," to respective frames of the Asian disease problem, Tversky and Kahneman were able to define framing effect. In this study, we preliminarily explored the effect of mixed frames, which are characterized by the use of different vocabulary in one frame. In study 1, we found that only the sure option description had significant effect on decision-making, while the effects of risky option descriptions were not significant, nor were interactions between descriptions. In study 2, the results suggested that after controlling the effects of the hedonic tone of the sure options, risky option description did not significantly predict decision-making. In study 3, we found that neither the sure-to-risky option presentation order nor presentation order within risky options had significant effect on decision-making. We thus concluded that sure option description can serve as the decision-making foundation (reference point) for decision-makers in mixed frames.

Automatic frame-centered object representation and integration revealed by iconic memory, visual priming, and backward masking.

Science.gov (United States)

Lin, Zhicheng; He, Sheng

2012-10-25

Object identities ("what") and their spatial locations ("where") are processed in distinct pathways in the visual system, raising the question of how the what and where information is integrated. Because of object motions and eye movements, the retina-based representations are unstable, necessitating nonretinotopic representation and integration. A potential mechanism is to code and update objects according to their reference frames (i.e., frame-centered representation and integration). To isolate frame-centered processes, in a frame-to-frame apparent motion configuration, we (a) presented two preceding or trailing objects on the same frame, equidistant from the target on the other frame, to control for object-based (frame-based) effect and space-based effect, and (b) manipulated the target's relative location within its frame to probe frame-centered effect. We show that iconic memory, visual priming, and backward masking depend on objects' relative frame locations, orthogonal of the retinotopic coordinate. These findings not only reveal that iconic memory, visual priming, and backward masking can be nonretinotopic but also demonstrate that these processes are automatically constrained by contextual frames through a frame-centered mechanism. Thus, object representation is robustly and automatically coupled to its reference frame and continuously being updated through a frame-centered, location-specific mechanism. These findings lead to an object cabinet framework, in which objects ("files") within the reference frame ("cabinet") are orderly coded relative to the frame.

FRAME, animal experimentation and the Three Rs: past, present and future.

Science.gov (United States)

Balls, Michael

2009-12-01

At the opening of a meeting to celebrate the 50th anniversary of the publication of The Principles of Humane Experimental Technique, by W.M.S. Russell and R.L. Burch, and the 40th anniversary of the establishment of FRAME, some comments on the early days of the Charity are made, with particular reference to the special contributions made by its founder-Chairman, Dorothy Hegarty, and the author's own appointment as a Trustee, and later as Chairman. Reference is made to some key events and successes, and especially to the importance of FRAME's move from London to Nottingham, and the establishment of an ongoing collaboration with the University of Nottingham, including the setting-up of the FRAME Alternatives Laboratory. 2009 FRAME.

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…

Further adventures of the celestial sleuth using astronomy to solve more mysteries in art, history, and literature

CERN Document Server

Olson, Donald W

2018-01-01

From the author of "Celestial Sleuth" (2014), yet more mysteries in art, history, and literature are solved by calculating phases of the Moon, determining the positions of the planets and stars, and identifying celestial objects in paintings. In addition to helping to crack difficult cases, these studies spark our imagination and provide a better understanding of the skies. Weather archives, vintage maps, tides, historical letters and diaries, military records and the assistance of experts in related fields help with this work. For each historical event influenced by astronomy, there is a different kind of mystery to be solved. How did the changing tides affect an army's battle plans? How did the phases of the moon affect how an artist painted a landscape? Follow these exciting investigations with a master “celestial sleuth” as he tracks down the truth and helps unravel mysteries as far back as the Middle Ages and as recent as the iconic 1945 photograph of a kiss in Times Square on VJ Day. Topics or "case...

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.

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

Science.gov (United States)

Koenig, Daniel

2018-02-01

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

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.

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.

Concepts and Contexts – Argumentative Forms of Framing

DEFF Research Database (Denmark)

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

2011-01-01

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.......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...

Plasma physics in noninertial frames

International Nuclear Information System (INIS)

Thyagaraja, A.; McClements, K. G.

2009-01-01

Equations describing the nonrelativistic motion of a charged particle in an arbitrary noninertial reference frame are derived from the relativistically invariant form of the particle action. It is shown that the equations of motion can be written in the same form in inertial and noninertial frames, with the effective electric and magnetic fields in the latter modified by inertial effects associated with centrifugal and Coriolis accelerations. These modifications depend on the particle charge-to-mass ratio, and also the vorticity, specific kinetic energy, and compressibility of the frame flow. The Newton-Lorentz, Vlasov, and Fokker-Planck equations in such a frame are derived. Reduced models such as gyrokinetic, drift-kinetic, and fluid equations are then derivable from these equations in the appropriate limits, using standard averaging procedures. The results are applied to tokamak plasmas rotating about the machine symmetry axis with a nonrelativistic but otherwise arbitrary toroidal flow velocity. Astrophysical applications of the analysis are also possible since the power of the action principle is such that it can be used to describe relativistic flows in curved spacetime.

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

The Influence of Framing on Risky Decisions: A Meta-analysis.

Science.gov (United States)

Kühberger

1998-07-01

In framing studies, logically equivalent choice situations are differently described and the resulting preferences are studied. A meta-analysis of framing effects is presented for risky choice problems which are framed either as gains or as losses. This evaluates the finding that highlighting the positive aspects of formally identical problems does lead to risk aversion and that highlighting their equivalent negative aspects does lead to risk seeking. Based on a data pool of 136 empirical papers that reported framing experiments with nearly 30,000 participants, we calculated 230 effect sizes. Results show that the overall framing effect between conditions is of small to moderate size and that profound differences exist between research designs. Potentially relevant characteristics were coded for each study. The most important characteristics were whether framing is manipulated by changing reference points or by manipulating outcome salience, and response mode (choice vs. rating/judgment). Further important characteristics were whether options differ qualitatively or quantitatively in risk, whether there is one or multiple risky events, whether framing is manipulated by gain/loss or by task-responsive wording, whether dependent variables are measured between- or within- subjects, and problem domains. Sample (students vs. target populations) and unit of analysis (individual vs. group) was not influential. It is concluded that framing is a reliable phenomenon, but that outcome salience manipulations, which constitute a considerable amount of work, have to be distinguished from reference point manipulations and that procedural features of experimental settings have a considerable effect on effect sizes in framing experiments. Copyright 1998 Academic Press.

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...

Frames of Mind in Intertemporal Choice

OpenAIRE

George F. Loewenstein

1988-01-01

Recent research has demonstrated that choices between gambles are systematically influenced by the way they are expressed. Kahneman and Tversky's Prospect Theory (Kahneman, D., A. Tversky. 1979. Prospect theory: An analysis of decision under risk. Econometrica 47(2) 363--391.) explains many of these "framing" effects as shifts in the point of reference from which prospects are evaluated. This paper demonstrates the applicability of the reference point concept to intertemporal choice. Three ex...

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)

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

Line selection in celestial masers

International Nuclear Information System (INIS)

Middleton, M.S.

1978-09-01

The primary themes of this work concern the applicability of the Cook (1975) filter mechanism to line selection in hydroxyl masers, and the question of whether interstellar hydroxyl, water, and silicon monoxide masers are saturated. Whether the Cook filter is operative in celestial masers has not thus far been decided, even though it has been shown that such an effect might be occurring. The theory in its present form does not account for line broadening, nor have its consequences with regard to microwave maser emission from excited states of hydroxyl been explored. Both these topics are discussed and the findings are compared with the observations of NGC 6334A, a source which is interesting because of the strong evidence for Zeeman splitting which can be seen in some of its observed spectra. The question of whether interstellar masers are saturated has been much discussed, but a simple method for determining the state of saturation of observed masers does not exist. In particular, the importance of background radiation and of different cloud geometries on the state of saturation of interstellar masers up to now has not been fully appreciated. Both these topics are discussed. (author)

Framing the frame

OpenAIRE

Todd McElroy; John J. Seta

2007-01-01

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 ty...

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.

Viewer-centered and body-centered frames of reference in direct visuomotor transformations.

Science.gov (United States)

Carrozzo, M; McIntyre, J; Zago, M; Lacquaniti, F

1999-11-01

It has been hypothesized that the end-point position of reaching may be specified in an egocentric frame of reference. In most previous studies, however, reaching was toward a memorized target, rather than an actual target. Thus, the role played by sensorimotor transformation could not be disassociated from the role played by storage in short-term memory. In the present study the direct process of sensorimotor transformation was investigated in reaching toward continuously visible targets that need not be stored in memory. A virtual reality system was used to present visual targets in different three-dimensional (3D) locations in two different tasks, one with visual feedback of the hand and arm position (Seen Hand) and the other without such feedback (Unseen Hand). In the Seen Hand task, the axes of maximum variability and of maximum contraction converge toward the mid-point between the eyes. In the Unseen Hand task only the maximum contraction correlates with the sight-line and the axes of maximum variability are not viewer-centered but rotate anti-clockwise around the body and the effector arm during the move from the right to the left workspace. The bulk of findings from these and previous experiments support the hypothesis of a two-stage process, with a gradual transformation from viewer-centered to body-centered and arm-centered coordinates. Retinal, extra-retinal and arm-related signals appear to be progressively combined in superior and inferior parietal areas, giving rise to egocentric representations of the end-point position of reaching.

Frame dependence of spin-one angular conditions in light front dynamics

International Nuclear Information System (INIS)

Bakker, Bernard L. G.; Ji Chuengryong

2002-01-01

We elaborate the frame dependence of the angular conditions for spin-1 form factors. An extra angular condition is found in addition to the usual angular condition relating the four helicity amplitudes. Investigating the frame dependence of angular conditions, we find that the extra angular condition is in general as complicated as the usual one, although it becomes very simple in the q + =0 frame involving only two helicity amplitudes. It is confirmed that the angular conditions are identical in frames that are connected by kinematical transformations. The high-Q 2 behavior of the physical form factors and the limiting behavior in special reference frames are also discussed

CONSTRUCTION THEORY AND NOISE ANALYSIS METHOD OF GLOBAL CGCS2000 COORDINATE FRAME

Directory of Open Access Journals (Sweden)

Z. Jiang

2018-04-01

Full Text Available The definition, renewal and maintenance of geodetic datum has been international hot issue. In recent years, many countries have been studying and implementing modernization and renewal of local geodetic reference coordinate frame. Based on the precise result of continuous observation for recent 15 years from state CORS (continuously operating reference system network and the mainland GNSS (Global Navigation Satellite System network between 1999 and 2007, this paper studies the construction of mathematical model of the Global CGCS2000 frame, mainly analyzes the theory and algorithm of two-step method for Global CGCS2000 Coordinate Frame formulation. Finally, the noise characteristic of the coordinate time series are estimated quantitatively with the criterion of maximum likelihood estimation.

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...

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

Science.gov (United States)

Kota, Venkata Reddy; Vinnakoti, Sudheer

2017-12-01

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

Quantum back-action-evading measurement of motion in a negative mass reference frame

Science.gov (United States)

Møller, Christoffer B.; Thomas, Rodrigo A.; Vasilakis, Georgios; Zeuthen, Emil; Tsaturyan, Yeghishe; Balabas, Mikhail; Jensen, Kasper; Schliesser, Albert; Hammerer, Klemens; Polzik, Eugene S.

2017-07-01

Quantum mechanics dictates that a continuous measurement of the position of an object imposes a random quantum back-action (QBA) perturbation on its momentum. This randomness translates with time into position uncertainty, thus leading to the well known uncertainty on the measurement of motion. As a consequence of this randomness, and in accordance with the Heisenberg uncertainty principle, the QBA puts a limitation—the so-called standard quantum limit—on the precision of sensing of position, velocity and acceleration. Here we show that QBA on a macroscopic mechanical oscillator can be evaded if the measurement of motion is conducted in the reference frame of an atomic spin oscillator. The collective quantum measurement on this hybrid system of two distant and disparate oscillators is performed with light. The mechanical oscillator is a vibrational ‘drum’ mode of a millimetre-sized dielectric membrane, and the spin oscillator is an atomic ensemble in a magnetic field. The spin oriented along the field corresponds to an energetically inverted spin population and realizes a negative-effective-mass oscillator, while the opposite orientation corresponds to an oscillator with positive effective mass. The QBA is suppressed by -1.8 decibels in the negative-mass setting and enhanced by 2.4 decibels in the positive-mass case. This hybrid quantum system paves the way to entanglement generation and distant quantum communication between mechanical and spin systems and to sensing of force, motion and gravity beyond the standard quantum limit.

Quantum back-action-evading measurement of motion in a negative mass reference frame.

Science.gov (United States)

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

2017-07-12

Quantum mechanics dictates that a continuous measurement of the position of an object imposes a random quantum back-action (QBA) perturbation on its momentum. This randomness translates with time into position uncertainty, thus leading to the well known uncertainty on the measurement of motion. As a consequence of this randomness, and in accordance with the Heisenberg uncertainty principle, the QBA puts a limitation-the so-called standard quantum limit-on the precision of sensing of position, velocity and acceleration. Here we show that QBA on a macroscopic mechanical oscillator can be evaded if the measurement of motion is conducted in the reference frame of an atomic spin oscillator. The collective quantum measurement on this hybrid system of two distant and disparate oscillators is performed with light. The mechanical oscillator is a vibrational 'drum' mode of a millimetre-sized dielectric membrane, and the spin oscillator is an atomic ensemble in a magnetic field. The spin oriented along the field corresponds to an energetically inverted spin population and realizes a negative-effective-mass oscillator, while the opposite orientation corresponds to an oscillator with positive effective mass. The QBA is suppressed by -1.8 decibels in the negative-mass setting and enhanced by 2.4 decibels in the positive-mass case. This hybrid quantum system paves the way to entanglement generation and distant quantum communication between mechanical and spin systems and to sensing of force, motion and gravity beyond the standard quantum limit.

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...

Effector-independent motor sequence representations exist in extrinsic and intrinsic reference frames.

Science.gov (United States)

Wiestler, Tobias; Waters-Metenier, Sheena; Diedrichsen, Jörn

2014-04-02

Many daily activities rely on the ability to produce meaningful sequences of movements. Motor sequences can be learned in an effector-specific fashion (such that benefits of training are restricted to the trained hand) or an effector-independent manner (meaning that learning also facilitates performance with the untrained hand). Effector-independent knowledge can be represented in extrinsic/world-centered or in intrinsic/body-centered coordinates. Here, we used functional magnetic resonance imaging (fMRI) and multivoxel pattern analysis to determine the distribution of intrinsic and extrinsic finger sequence representations across the human neocortex. Participants practiced four sequences with one hand for 4 d, and then performed these sequences during fMRI with both left and right hand. Between hands, these sequences were equivalent in extrinsic or intrinsic space, or were unrelated. In dorsal premotor cortex (PMd), we found that sequence-specific activity patterns correlated higher for extrinsic than for unrelated pairs, providing evidence for an extrinsic sequence representation. In contrast, primary sensory and motor cortices showed effector-independent representations in intrinsic space, with considerable overlap of the two reference frames in caudal PMd. These results suggest that effector-independent representations exist not only in world-centered, but also in body-centered coordinates, and that PMd may be involved in transforming sequential knowledge between the two. Moreover, although effector-independent sequence representations were found bilaterally, they were stronger in the hemisphere contralateral to the trained hand. This indicates that intermanual transfer relies on motor memories that are laid down during training in both hemispheres, but preferentially draws upon sequential knowledge represented in the trained hemisphere.

Outputs of paired Gabor filters summed across the background frame of reference predict the direction of movement

Science.gov (United States)

Lawton, Teri B.

1989-01-01

A cortical neural network that computes the visibility of shifts in the direction of movement is proposed. The network computes: (1) the magnitude of the position difference between the test and background patterns, (2) localized contrast differences at different spatial scales analyzed by computing temporal gradients of the difference and sum of the outputs of paired even- and odd-symmetric bandpass filters convolved with the input pattern, and (3) using global processes that pool the output from paired even- and odd-symmetric simple and complex cells across the spatial extent of the background frame of reference the direction a test pattern moved relative to a textured background. Evidence that magnocellular pathways are used to discriminate the direction of movement is presented. Since magnocellular pathways are used to discriminate the direction of movement, this task is not affected by small pattern changes such as jitter, short presentations, blurring, and different background contrasts that result when the veiling illumination in a scene changes.

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.

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.

Brain potentials associated with the outcome processing in framing effects.

Science.gov (United States)

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

2012-10-24

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

Roadmap to a mutually consistent set of offshore vertical reference frames

NARCIS (Netherlands)

Slobbe, D.C.

2013-01-01

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

On transforms between Gabor frames and wavelet frames

DEFF Research Database (Denmark)

Christensen, Ole; Goh, Say Song

2013-01-01

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

Concise CIO based precession-nutation formulations

Science.gov (United States)

Capitaine, N.; Wallace, P. T.

2008-01-01

Context: The IAU 2000/2006 precession-nutation models have precision goals measured in microarcseconds. To reach this level of performance has required series containing terms at over 1300 frequencies and involving several thousand amplitude coefficients. There are many astronomical applications for which such precision is not required and the associated heavy computations are wasteful. This justifies developing smaller models that achieve adequate precision with greatly reduced computing costs. Aims: We discuss strategies for developing simplified IAU 2000/2006 precession-nutation procedures that offer a range of compromises between accuracy and computing costs. Methods: The chain of transformations linking celestial and terrestrial coordinates comprises frame bias, precession-nutation, Earth rotation and polar motion. We address the bias and precession-nutation (NPB) portion of the chain, linking the Geocentric Celestial Reference System (GCRS) with the Celestial Intermediate Reference System (CIRS), the latter based on the Celestial Intermediate Pole (CIP) and Celestial Intermediate Origin (CIO). Starting from direct series that deliver the CIP coordinates X,Y and (via the quantity s + XY/2) the CIO locator s, we look at the opportunities for simplification. Results: The biggest reductions come from truncating the series, but some additional gains can be made in the areas of the matrix formulation, the expressions for the nutation arguments and by subsuming long period effects into the bias quantities. Three example models are demonstrated that approximate the IAU 2000/2006 CIP to accuracies of 1 mas, 16 mas and 0.4 arcsec throughout 1995-2050 but with computation costs reduced by 1, 2 and 3 orders of magnitude compared with the full model. Appendices A to G are only available in electronic form at http://www.aanda.org

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

Directory of Open Access Journals (Sweden)

Gerdi Mulder

2013-07-01

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

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

Science.gov (United States)

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

2014-08-01

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

Analysis of frame structure of medium and small truck crane

Science.gov (United States)

Cao, Fuyi; Li, Jinlong; Cui, Mengkai

2018-03-01

Truck crane is an important part of hoisting machinery. Frame, as the support component of the quality of truck crane, determines the safety of crane jib load and the rationality of structural design. In this paper, the truck crane frame is a box structure, the three-dimensional model is established in CATIA software, and imported into Hyperworks software for finite element analysis. On the base of doing constraints and loads for the finite element model of the frame, the finite element static analysis is carried out. And the static stress test verifies whether the finite element model and the frame structure design are reasonable; then the free modal analysis of the frame and the analysis of the first 8 - order modal vibration deformation are carried out. The analysis results show that the maximum stress value of the frame is greater than the yield limit value of the material, and the low-order modal value is close to the excitation frequency value, which needs to be improved to provide theoretical reference for the structural design of the truck crane frame.

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

Science.gov (United States)

Bulatova, Natalia P.

2011-09-01

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

On an Allan variance approach to classify VLBI radio-sources on the basis of their astrometric stability

Science.gov (United States)

Gattano, C.; Lambert, S.; Bizouard, C.

2017-12-01

In the context of selecting sources defining the celestial reference frame, we compute astrometric time series of all VLBI radio-sources from observations in the International VLBI Service database. The time series are then analyzed with Allan variance in order to estimate the astrometric stability. From results, we establish a new classification that takes into account the whole multi-time scales information. The algorithm is flexible on the definition of ``stable source" through an adjustable threshold.

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

Science.gov (United States)

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

2017-09-01

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

Case study of a framing effect in course evaluations.

Science.gov (United States)

Lynöe, Niels; Juth, Niklas; Helgesson, Gert

2012-01-01

When new elements are included in the medical curriculum and the total time frame remains unchanged, established disciplines have to shorten their courses. This might bring about frustration among the teachers and students concerned, which in turn might affect how other courses are perceived. Two course evaluations, one before and one after a major change in the curriculum were compared. Comments were also analysed. We found that the students' and teachers' frustration influenced the students' evaluations of a new course in the philosophy of medicine and accordingly brought about an unintended message effect referred to as a framing effect. The results of this observational study indicate that a negative framing effect might influence course-evaluations. We suggest that this study might be used as a point of departure for further empirical studies about negative framing effects.

Reference frames for spatial frequency in face representation differ in the temporal visual cortex and amygdala.

Science.gov (United States)

Inagaki, Mikio; Fujita, Ichiro

2011-07-13

Social communication in nonhuman primates and humans is strongly affected by facial information from other individuals. Many cortical and subcortical brain areas are known to be involved in processing facial information. However, how the neural representation of faces differs across different brain areas remains unclear. Here, we demonstrate that the reference frame for spatial frequency (SF) tuning of face-responsive neurons differs in the temporal visual cortex and amygdala in monkeys. Consistent with psychophysical properties for face recognition, temporal cortex neurons were tuned to image-based SFs (cycles/image) and showed viewing distance-invariant representation of face patterns. On the other hand, many amygdala neurons were influenced by retina-based SFs (cycles/degree), a characteristic that is useful for social distance computation. The two brain areas also differed in the luminance contrast sensitivity of face-responsive neurons; amygdala neurons sharply reduced their responses to low luminance contrast images, while temporal cortex neurons maintained the level of their responses. From these results, we conclude that different types of visual processing in the temporal visual cortex and the amygdala contribute to the construction of the neural representations of faces.

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

Directory of Open Access Journals (Sweden)

Katrin eJohannsen

2013-04-01

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

Attribute Framing and Goal Framing Effects in Health Decisions.

Science.gov (United States)

Krishnamurthy, Parthasarathy; Carter, Patrick; Blair, Edward

2001-07-01

Levin, Schneider, and Gaeth (LSG, 1998) have distinguished among three types of framing-risky choice, attribute, and goal framing-to reconcile conflicting findings in the literature. In the research reported here, we focus on attribute and goal framing. LSG propose that positive frames should be more effective than negative frames in the context of attribute framing, and negative frames should be more effective than positive frames in the context of goal framing. We test this framework by manipulating frame valence (positive vs negative) and frame type (attribute vs goal) in a unified context with common procedures. We also argue that the nature of effects in a goal-framing context may depend on the extent to which the research topic has "intrinsic self-relevance" to the population. In the context of medical decision making, we operationalize low intrinsic self-relevance by using student subjects and high intrinsic self-relevance by using patients. As expected, we find complete support for the LSG framework under low intrinsic self-relevance and modified support for the LSG framework under high intrinsic self-relevance. Overall, our research appears to confirm and extend the LSG framework. Copyright 2001 Academic Press.

Frame model of knowledge in quality control systems

Energy Technology Data Exchange (ETDEWEB)

Macherauskas, V.Yu.

1982-09-01

The purpose of this article is to develop a semiotic model for representation of data and knowledge in a system for supplying operational information to management personnel on the progress of a technological process, with the aim of enabling an analysis of deviations of product quality and formulation of recommendations to the technologists as to how to eliminate them. Since any knowledge of people that can be realistically utilized in machine systems is represented in natural language form, special languages for representation of knowledge, based on the concept of frames, are being developed for formation of semiotic models in computers. This article defines the frames, followed by a description of a mechanism of knowledge manipulation and of some aspects of realization of a frame model of knowledge. 9 references.

Solid-state framing camera with multiple time frames

Energy Technology Data Exchange (ETDEWEB)

Baker, K. L.; Stewart, R. E.; Steele, P. T.; Vernon, S. P.; Hsing, W. W.; Remington, B. A. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

2013-10-07

A high speed solid-state framing camera has been developed which can operate over a wide range of photon energies. This camera measures the two-dimensional spatial profile of the flux incident on a cadmium selenide semiconductor at multiple times. This multi-frame camera has been tested at 3.1 eV and 4.5 keV. The framing camera currently records two frames with a temporal separation between the frames of 5 ps but this separation can be varied between hundreds of femtoseconds up to nanoseconds and the number of frames can be increased by angularly multiplexing the probe beam onto the cadmium selenide semiconductor.

Nonmonotonic belief state frames and reasoning frames

NARCIS (Netherlands)

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

1995-01-01

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

Self- and Other-Referent Criteria of Career Success.

Science.gov (United States)

Heslin, Peter A.

2003-01-01

Business students (n=71) evaluated their career success thus far. Framed by social comparison theory, results showed that 68% used other-referent criteria to assess their success. Participants who believed that ability and personality are fixed attributes had greater reliance on other-referent criteria. (Contains 100 references.) (SK)

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

CERN Document Server

Arnold, Vladimir I; Khesin, Boris

2010-01-01

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

Astronomical relativistic reference systems with multipolar expansion: the global one

International Nuclear Information System (INIS)

Xie Yi

2014-01-01

With the rapid development of techniques for astronomical observations, the precision of measurements has been significantly increasing. Theories describing astronomical relativistic reference systems, which are the foundation for processing and interpreting these data now and in the future, may require extensions to satisfy the needs of these trends. Besides building a framework compatible with alternative theories of gravity and the pursuit of higher order post-Newtonian approximation, it will also be necessary to make the first order post-Newtonian multipole moments of celestial bodies be explicitly expressed in the astronomical relativistic reference systems. This will bring some convenience into modeling the observations and experiments and make it easier to distinguish different contributions in measurements. As a first step, the global solar system reference system is expressed as a multipolar expansion and the post-Newtonian mass and spin moments are shown explicitly in the metric which describes the coordinates of the system. The full expression of the global metric is given. (research papers)

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

Science.gov (United States)

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

2017-07-01

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

General Eulerian formulation of the comoving-frame equation of radiative transfer

International Nuclear Information System (INIS)

Riffert, H.

1986-01-01

For a wide range of problems in radiation hydrodynamics the motion of the matter is best described in an Eulerian coordinate system, and here a comoving-frame equation of radiation transfer in such fixed coordinates is derived, using the radiation quantities measured in the comoving frame. The choice of coordinates is arbitrary, and the equation is given explicitly for an arbitrary diagonal metric, correct to all orders in v/c. All comoving frame equations derived earlier are included as special cases. An example is given for the case of a spherically symmetric flow in a Schwarzschild metric. 9 references

Patch-based frame interpolation for old films via the guidance of motion paths

Science.gov (United States)

Xia, Tianran; Ding, Youdong; Yu, Bing; Huang, Xi

2018-04-01

Due to improper preservation, traditional films will appear frame loss after digital. To deal with this problem, this paper presents a new adaptive patch-based method of frame interpolation via the guidance of motion paths. Our method is divided into three steps. Firstly, we compute motion paths between two reference frames using optical flow estimation. Then, the adaptive bidirectional interpolation with holes filled is applied to generate pre-intermediate frames. Finally, using patch match to interpolate intermediate frames with the most similar patches. Since the patch match is based on the pre-intermediate frames that contain the motion paths constraint, we show a natural and inartificial frame interpolation. We test different types of old film sequences and compare with other methods, the results prove that our method has a desired performance without hole or ghost effects.

Monitoring of Earth Rotation by VLBI

Science.gov (United States)

Ma., Chopo; Macmillan, D. S.

2000-01-01

Monitoring Earth rotation with Very Long Baseline Interferometry (VLBI) has unique potential because of direct access to the Celestial Reference System (CRF and Terrestrial Reference System (TRF) and the feasibility of re-analyzing the entire data set. While formal precision of better than 0.045 mas for pole and 0.002 ms for UT 1 has been seen in the best 24-hr data, the accuracy of the Earth Orientation Parameter (EOP) time series as a whole is subject to logistical, operational, analytical and conceptual constraints. The current issues related to the VLBI data set and the CORE program for greater time resolution such as analysis consistency, network jitter and reference frame stability will be discussed.

Framing effects in choices between multioutcome life-expectancy lotteries.

Science.gov (United States)

Bernstein, L M; Chapman, G B; Elstein, A S

1999-01-01

To explore framing or editing effects and a method to debias framing in a clinical context. Clinical scenarios using multioutcome life-expectancy lotteries of equal value required choices between two supplementary drugs that either prolonged or shortened life from the 20-year beneficial effect of a baseline drug. The effects of these supplementary drugs were presented in two conditions, using a between-subjects design. In segregated editing (n = 116) the effects were presented separately from the effects of the baseline drug. In integrated editing (n = 100), effects of supplementary and baseline drugs were combined in the lottery presentation. Each subject responded to 30 problems. To explore one method of debiasing, another 100 subjects made choices after viewing both segregated and integrated editings of 20 problems (dual framing). Statistically significant preference reversals between segregated and integrated editing of pure lotteries occurred only when one framing placed outcomes in the gain domain, and the other framing placed them in the loss domain. When both editings resulted in gain-domain outcomes only, there was no framing effect. There was a related relationship of framing-effect shifts from losses to gains in mixed-lottery-choice problems. Responses to the dual framing condition did not consistently coincide with responses to either single framing. In some situations, dual framing eliminated or lessened framing effects. The results support two components of prospect theory, coding outcomes as gains or losses from a reference point, and an s-shaped utility function (concave in gain, convex in loss domains). Presenting both alternative editings of a complex situation prior to choice more fully informs the decision maker and may help to reduce framing effects. Given the extent to which preferences shift in response to alternative presentations, it is unclear which choice represents the subject's "true preferences."

Discovering Mira Ceti: Celestial Change and Cosmic Continuity

Science.gov (United States)

Hatch, Robert Alan

In the short narrative that follows I introduce two new heroes. Although we begin with Fabricius's first sighting in 1596, the new pivot point in the drama is the collaboration between Hevelius and Boulliau that began around 1660. As it happens, Learned Europe paid little attention to Mira in the generation after the first scattered sightings of 1596, indeed, nearly 70 years passed before the New Star was given a working identity. Like Columbus discovering America, Fabricius and Holwarda saw different things - for convenience, I call them Fabricius's Star and Holwarda's Star. Hevelius's Historiola (Danzig, 1662) and Boulliau's Ad astronomos (Paris, 1667) presented a different vision. It made Mira famous. As I shall argue, if Hevelius gave Mira a history, Boulliau gave Mira a future.5 In the end, the New Star not only challenged the ancient cosmos, it became an enduring icon for the New Science, a returning reminder of celestial continuity and cosmic order.

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

International Nuclear Information System (INIS)

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

2010-01-01

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

The Atacama Cosmology Telescope : Physical Properties of Sunyaev-Zel'dovich Effect Clusters on the Celestial Equator

NARCIS (Netherlands)

Menanteau, F.; Sifon, Andalaft C.J.; Barrientos, L.; Battaglia, N.; Bond, J.; Crichton, D.; Das, S.; Devlin, M.; Dicker, S.; Dünner, R.; Gralla, M.; Hajian, A.; Hasselfield, M.; Hilton, M.; Hincks, A.; Hughes, J.; Infante, L.; Kosowsky, A.; Marriage, T.; Marsden, D.; Moodley, K.; Niemack, M.; Nolta, M.; Page, L.; Partridge, B.; Reese, E.; Schmitt, B.; Sievers, J.; Spergel, D.; Staggs, S.; Switzer, E.; Wollack, E.

2013-01-01

We present the optical and X-ray properties of 68 galaxy clusters selected via the Sunyaev-Zel'dovich (SZ) effect at 148 GHz by the Atacama Cosmology Telescope (ACT). Our sample, from an area of 504 deg$^{2}$ centered on the celestial equator, is divided into two regions. The main region uses 270

The Experimental Research on Seismic Capacity of the Envelope Systems with Steel Frame

Science.gov (United States)

Li, Jiuyang; Wang, Bingbing; Li, Hengxu

2017-09-01

In this paper, according to the present application situation of the external envelope systems steel frame in the severe cold region, the stuffed composite wall panels are improved, the flexible connection with the steel frame is designed, the reduced scale specimens are made, the seismic capacity test is made and some indexes of the envelope systems such as bearing capacity, energy consumption and ductility, etc. are compared, which provide reference for the development and application of the steel frame envelope systems.

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".

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

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

Science.gov (United States)

2016-08-10

gram (MSP) Geographic Translator (GEOTRANS) that is offered with source code in C++ and Java from the NGA at http://earth-info.nga.mil/GandG/geotrans...as their angular displacements in the sky are minimal over time. For example, Fig. 5 illustrates the predicted motion of the stars near Barnard’s star...LOD Length of day. The derivative of the DT with respect to TAI; proportional to the Earth’s angular velocity. dX,dY Celestial pole offsets. Offsets of

Framing of health information messages.

Science.gov (United States)

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

2011-12-07

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

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),

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

Science.gov (United States)

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

2014-09-21

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

Riesz frames and approximation of the frame coefficients

DEFF Research Database (Denmark)

Casazza, P.; Christensen, Ole

1998-01-01

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

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...

Toward an Understanding of Reference-Dependent Labor Supply

DEFF Research Database (Denmark)

Andersen, Steffen; Brandon, Alec; Gneezy, Uri

Perhaps the most powerful form of framing arises through reference dependence, wherein choices are made recognizing the starting point or a goal. In labor economics, for example, a form of reference dependence, income targeting, has been argued to represent a serious challenge to traditional...

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...

Writing More Informative Letters of Reference

OpenAIRE

Wright, Scott M; Ziegelstein, Roy C

2004-01-01

Writing a meaningful and valuable letter of reference is not an easy task. Several factors influence the quality of any letter of reference. First, the accuracy and reliability of the writer's impressions and judgment depend on how well he knows the individual being described. Second, the writer's frame of reference, which is determined by the number of persons at the same level that he has worked with, will impact the context and significance of his beliefs and estimations. Third, the letter...

Postglacial Rebound from VLBI Geodesy: On Establishing Vertical Reference

Science.gov (United States)

Argus, Donald F.

1996-01-01

Difficulty in establishing a reference frame fixed to the earth's interior complicates the measurement of the vertical (radial) motions of the surface. I propose that a useful reference frame for vertical motions is that found by minimizing differences between vertical motions observed with VLBI [Ma and Ryan] and predictions from postglacial rebound predictions [Peltier]. The optimal translation of the geocenter is 1.7mm/year toward 36degN, 111degE when determined from the motions of 10 VLBI sites. This translation gives a better fit of observations to predictions than does the VLBI reference frame used by Ma and Ryan, but the improvement is statistically insignificant. The root mean square of differences decreases 20% to 0.73 mm/yr and the correlation coefficient increases from 0.76 to 0.87. Postglacial rebound is evident in the uplift of points in Sweden and Ontario that were beneath the ancient ice sheets of Fennoscandia and Canada, and in the subsidence of points in the northeastern U.S., Germany, and Alaska that were around the periphery of the ancient ice sheets.

Frame scaling function sets and frame wavelet sets in Rd

International Nuclear Information System (INIS)

Liu Zhanwei; Hu Guoen; Wu Guochang

2009-01-01

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

Dynamics of entanglement under decoherence in noninertial frames

International Nuclear Information System (INIS)

Shi Jia-Dong; Wu Tao; Song Xue-Ke; Ye Liu

2014-01-01

In this paper, we investigate the entanglement dynamics of a two-qubit entangled state coupled with its noisy environment, and plan to utilize weak measurement and quantum reversal measurement to study the entanglement dynamics under different decoherence channels in noninertial frames. Through the calculations and analyses, it is shown that the weak measurement can prevent entanglement from coupling to the amplitude damping channel, while the system is under the phase damping and flip channels. This protection protocol cannot prevent entanglement but will accelerate the death of entanglement. In addition, if the system is in the noninertial reference frame, then the effect of weak measurement will be weakened for the amplitude damping channel. Nevertheless, for other decoherence channels, the Unruh effect does not affect the quantum weak measurement, the only exception is that the maximum value of entanglement is reduced to √2/2 of the original value in the inertial frames. (general)

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.

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

Science.gov (United States)

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

2012-06-01

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

Riesz Frames and Approximation of the Frame Coefficients

DEFF Research Database (Denmark)

Christensen, Ole

1996-01-01

A frame is a familyof elements in a Hilbert space with the propertythat every element in the Hilbert space can be written as a (infinite)linear combination of the frame elements. Frame theory describes howone can choose the corresponding coefficients, which are calledframe coefficients. From...... the mathematical point of view this isgratifying, but for applications it is a problem that the calculationrequires inversion of an operator on the Hilbert space.The projection method is introduced in order to avoid this problem.The basic idea is to consider finite subfamiliesof the frame and the orthogonal...... projection onto its span. Forfin QTR H,P_nf has a representation as a linear combinationof f_i,i=1,2,..,n, and the corresponding coefficients can be calculatedusing finite dimensional methods. We find conditions implying that thosecoefficients converge to the correct frame coefficients as n goes...

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...

Frames and counter-frames giving meaning to dementia: a framing analysis of media content.

Science.gov (United States)

Van Gorp, Baldwin; Vercruysse, Tom

2012-04-01

Media tend to reinforce the stigmatization of dementia as one of the most dreaded diseases in western society, which may have repercussions on the quality of life of those with the illness. The persons with dementia, but also those around them become imbued with the idea that life comes to an end as soon as the diagnosis is pronounced. The aim of this paper is to understand the dominant images related to dementia by means of an inductive framing analysis. The sample is composed of newspaper articles from six Belgian newspapers (2008-2010) and a convenience sample of popular images of the condition in movies, documentaries, literature and health care communications. The results demonstrate that the most dominant frame postulates that a human being is composed of two distinct parts: a material body and an immaterial mind. If this frame is used, the person with dementia ends up with no identity, which is in opposition to the Western ideals of personal self-fulfilment and individualism. For each dominant frame an alternative counter-frame is defined. It is concluded that the relative absence of counter-frames confirms the negative image of dementia. The inventory might be a help for caregivers and other professionals who want to evaluate their communication strategy. It is discussed that a more resolute use of counter-frames in communication about dementia might mitigate the stigma that surrounds dementia. Copyright © 2012 Elsevier Ltd. All rights reserved.

On correlation comparison of identical pions in different systems of reference

International Nuclear Information System (INIS)

Podgoretskij, M.I.

1983-01-01

It is shown that a comparison of correlations of identical pions in reference frames moving with different velocities along the reaction axis enables one to select the frame for which there is a kinematical symmetry in the multiple generation process. The indicated possibility is due to the fact that in the considered symmetrical frame the space-time parameters R and tau are extremal. An experimental selection of the ''symmetrical frame'' may be useful in the choice between competing models of multiple generation

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

Science.gov (United States)

Germanà, C.

2012-02-01

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

Body frames and frame singularities for three-atom systems

International Nuclear Information System (INIS)

Littlejohn, R.G.; Mitchell, K.A.; Aquilanti, V.; Cavalli, S.

1998-01-01

The subject of body frames and their singularities for three-particle systems is important not only for large-amplitude rovibrational coupling in molecular spectroscopy, but also for reactive scattering calculations. This paper presents a geometrical analysis of the meaning of body frame conventions and their singularities in three-particle systems. Special attention is devoted to the principal axis frame, a certain version of the Eckart frame, and the topological inevitability of frame singularities. The emphasis is on a geometrical picture, which is intended as a preliminary study for the more difficult case of four-particle systems, where one must work in higher-dimensional spaces. The analysis makes extensive use of kinematic rotations. copyright 1998 The American Physical Society

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

Science.gov (United States)

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

2013-04-01

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

Frame on frames: an annotated bibliography

International Nuclear Information System (INIS)

Wright, T.; Tsao, H.J.

1983-01-01

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

Star identification methods, techniques and algorithms

CERN Document Server

Zhang, Guangjun

2017-01-01

This book summarizes the research advances in star identification that the author’s team has made over the past 10 years, systematically introducing the principles of star identification, general methods, key techniques and practicable algorithms. It also offers examples of hardware implementation and performance evaluation for the star identification algorithms. Star identification is the key step for celestial navigation and greatly improves the performance of star sensors, and as such the book include the fundamentals of star sensors and celestial navigation, the processing of the star catalog and star images, star identification using modified triangle algorithms, star identification using star patterns and using neural networks, rapid star tracking using star matching between adjacent frames, as well as implementation hardware and using performance tests for star identification. It is not only valuable as a reference book for star sensor designers and researchers working in pattern recognition and othe...

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.

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

International Nuclear Information System (INIS)

Semenov, Alexander; Babikov, Dmitri

2013-01-01

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

A soil sampling reference site: The challenge in defining reference material for sampling

International Nuclear Information System (INIS)

De Zorzi, Paolo; Barbizzi, Sabrina; Belli, Maria; Fajgelj, Ales; Jacimovic, Radojko; Jeran, Zvonka; Sansone, Umberto; Perk, Marcel van der

2008-01-01

In the frame of the international SOILSAMP project, funded and coordinated by the Italian Environmental Protection Agency, an agricultural area was established as a reference site suitable for performing soil sampling inter-comparison exercises. The reference site was characterized for trace element content in soil, in terms of the spatial and temporal variability of their mass fraction. Considering that the behaviour of long-lived radionuclides in soil can be expected to be similar to that of some stable trace elements and that the distribution of these trace elements in soil can simulate the distribution of radionuclides, the reference site characterised in term of trace elements, can be also used to compare the soil sampling strategies developed for radionuclide investigations

A soil sampling reference site: The challenge in defining reference material for sampling

Energy Technology Data Exchange (ETDEWEB)

De Zorzi, Paolo [Agenzia per la Protezione dell' Ambiente e per i Servizi Tecnici (APAT), Servizio Metrologia Ambientale, Via di Castel Romano, Rome 100-00128 (Italy)], E-mail: paolo.dezorzi@apat.it; Barbizzi, Sabrina; Belli, Maria [Agenzia per la Protezione dell' Ambiente e per i Servizi Tecnici (APAT), Servizio Metrologia Ambientale, Via di Castel Romano, Rome 100-00128 (Italy); Fajgelj, Ales [International Atomic Energy Agency (IAEA), Agency' s Laboratories Seibersdorf, Vienna A-1400 (Austria); Jacimovic, Radojko; Jeran, Zvonka; Sansone, Umberto [Jozef Stefan Institute, Jamova 39, Ljubljana 1000 (Slovenia); Perk, Marcel van der [Department of Physical Geography, Utrecht University, P.O. Box 80115, TC Utrecht 3508 (Netherlands)

2008-11-15

In the frame of the international SOILSAMP project, funded and coordinated by the Italian Environmental Protection Agency, an agricultural area was established as a reference site suitable for performing soil sampling inter-comparison exercises. The reference site was characterized for trace element content in soil, in terms of the spatial and temporal variability of their mass fraction. Considering that the behaviour of long-lived radionuclides in soil can be expected to be similar to that of some stable trace elements and that the distribution of these trace elements in soil can simulate the distribution of radionuclides, the reference site characterised in term of trace elements, can be also used to compare the soil sampling strategies developed for radionuclide investigations.

A soil sampling reference site: the challenge in defining reference material for sampling.

Science.gov (United States)

de Zorzi, Paolo; Barbizzi, Sabrina; Belli, Maria; Fajgelj, Ales; Jacimovic, Radojko; Jeran, Zvonka; Sansone, Umberto; van der Perk, Marcel

2008-11-01

In the frame of the international SOILSAMP project, funded and coordinated by the Italian Environmental Protection Agency, an agricultural area was established as a reference site suitable for performing soil sampling inter-comparison exercises. The reference site was characterized for trace element content in soil, in terms of the spatial and temporal variability of their mass fraction. Considering that the behaviour of long-lived radionuclides in soil can be expected to be similar to that of some stable trace elements and that the distribution of these trace elements in soil can simulate the distribution of radionuclides, the reference site characterised in term of trace elements, can be also used to compare the soil sampling strategies developed for radionuclide investigations.

iGRaND: an invariant frame for RGBD sensor feature detection and descriptor extraction with applications

Science.gov (United States)

Willis, Andrew R.; Brink, Kevin M.

2016-06-01

This article describes a new 3D RGBD image feature, referred to as iGRaND, for use in real-time systems that use these sensors for tracking, motion capture, or robotic vision applications. iGRaND features use a novel local reference frame derived from the image gradient and depth normal (hence iGRaND) that is invariant to scale and viewpoint for Lambertian surfaces. Using this reference frame, Euclidean invariant feature components are computed at keypoints which fuse local geometric shape information with surface appearance information. The performance of the feature for real-time odometry is analyzed and its computational complexity and accuracy is compared with leading alternative 3D features.

Moderating Effects of Consumer Involvement and the Need for Cognition on Goal Framing

Directory of Open Access Journals (Sweden)

Leandro Miletto Tonetto

2010-01-01

Full Text Available Goal framing effect refers to the finding that different ways of presenting the same communication content to a consumer tends to generate distinct levels of persuasion for the emitted message. This research is aimed at investigating the interaction between goal framing effect, consumer involvement and the Need for Cognition (NfC on consumer decision making. Two experiments have been carried out to test the hypothesis that the level of persuasion for a promotional text elevates as consumer involvement increases, independent of the message frame or the NfC. Results showed that consumer's involvement seemed to draw the text's persuasion level up, as it increases, or down, as it decreases, independent of the text frame and the NfC.

Some aspects of an induced electric dipole moment in rotating and non-rotating frames.

Science.gov (United States)

Oliveira, Abinael B; Bakke, Knut

2017-06-01

Quantum effects on a neutral particle (atom or molecule) with an induced electric dipole moment are investigated when it is subject to the Kratzer potential and a scalar potential proportional to the radial distance. In addition, this neutral is placed in a region with electric and magnetic fields. This system is analysed in both non-rotating and rotating reference frames. Then, it is shown that bound state solutions to the Schrödinger equation can be achieved and, in the search for polynomial solutions to the radial wave function, a restriction on the values of the cyclotron frequency is analysed in both reference frames.

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.

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

International Nuclear Information System (INIS)

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

1992-01-01

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

Analysis of Truss Frames by Method of the Stiffness Matrix

Science.gov (United States)

1990-12-01

of the web members of the truss. There also are variations in the truss frame given by the geometric shape of the frame, also referred to in some...at the elastic center, 0 (Figure .3.2), are: R AX = Wix - Hot RBX W2x -Ho, RAY =WIY + Vo, (1) RBy WLy - Vo, MAB =- Mo + CH. + aVo + CMA, MBA =M - CH...o Co Ce Substituting the results of Equation (7) into Equations (1), x c D x RAY = Wix + + -- (eA - GO - D (8)C x C x C cx x cx AY a D RAY

Behaviour of Strengthened RC Frames with Eccentric Steel Braced Frames

Science.gov (United States)

Kamanli, Mehmet; Unal, Alptug

2017-10-01

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

Approximately dual frames in Hilbert spaces and applications to Gabor frames

OpenAIRE

Christensen, Ole; Laugesen, Richard S.

2011-01-01

Approximately dual frames are studied in the Hilbert space setting. Approximate duals are easier to construct than classical dual frames, and can be tailored to yield almost perfect reconstruction. Bounds on the deviation from perfect reconstruction are obtained for approximately dual frames constructed via perturbation theory. An alternative bound is derived for the rich class of Gabor frames, by using the Walnut representation of the frame operator to estimate the deviation from equality in...

Framing the frame: How task goals determine the likelihood and direction of framing effects

OpenAIRE

Todd McElroy; John J. Seta

2007-01-01

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 ty...

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

Mars Science Laboratory Frame Manager for Centralized Frame Tree Database and Target Pointing

Science.gov (United States)

Kim, Won S.; Leger, Chris; Peters, Stephen; Carsten, Joseph; Diaz-Calderon, Antonio

2013-01-01

The FM (Frame Manager) flight software module is responsible for maintaining the frame tree database containing coordinate transforms between frames. The frame tree is a proper tree structure of directed links, consisting of surface and rover subtrees. Actual frame transforms are updated by their owner. FM updates site and saved frames for the surface tree. As the rover drives to a new area, a new site frame with an incremented site index can be created. Several clients including ARM and RSM (Remote Sensing Mast) update their related rover frames that they own. Through the onboard centralized FM frame tree database, client modules can query transforms between any two frames. Important applications include target image pointing for RSM-mounted cameras and frame-referenced arm moves. The use of frame tree eliminates cumbersome, error-prone calculations of coordinate entries for commands and thus simplifies flight operations significantly.

Behaviour of Strengthened RC Frames with Eccentric Steel Braced Frames

Directory of Open Access Journals (Sweden)

Kamanli Mehmet

2017-01-01

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

Improvement of Quality of Reconstructed Images in Multi-Frame Fresnel Digital Holography

International Nuclear Information System (INIS)

Xiao-Wei, Lu; Jing-Zhen, Li; Hong-Yi, Chen

2010-01-01

A modified reconstruction algorithm to improve the quality of reconstructed images of multi-frame Fresnel digital holography is presented. When the reference beams are plane or spherical waves with azimuth encoding, by introducing two spherical wave factors, images can be reconstructed with only one time Fourier transform. In numerical simulation, this algorithm could simplify the reconstruction process and improve the signal-to-noise ratio of the reconstructed images. In single-frame reconstruction experiments, the accurate reconstructed image is obtained with this simplified algorithm

George William Hill, the Great but Unknown 19th Century Celestial Mechanician

Science.gov (United States)

Corbin, Brenda G.

2012-01-01

George William Hill (1838-1914) has long been considered one of the most famous and talented celestial mechanicians of the past century and a half. However, many people have never heard of him and his work. Simon Newcomb said he "will easily rank as the greatest master of mathematical astronomy during the last quarter of the nineteenth century.” After receiving a B.A. at Rutgers in 1859, Hill began work in 1861 at the office of the American Ephemeris and Nautical Almanac in Cambridge, MA. He moved to Washington with the group in 1882 which then became part of the U. S. Naval Observatory. Newcomb, beginning his work on planetary motion, assigned the theory of Jupiter and Saturn to him, calling it about the most difficult topic. Hill's work was published by the USNO in 1890 as A New Theory of Jupiter and Saturn. From 1898 to 1901, Hill lectured on the subject of celestial mechanics at Columbia University in a position created just for him. After 1892 and until his death, he lived at the family homestead in West Nyack, NY. He never married, was something of a recluse, and spent most of his time with his books and research. Hill was an amateur botanist and enjoyed exploring on long walks in the countryside. Many honors and awards came to him during his lifetime, both from the U.S. and abroad, including serving as president of the American Mathematical Society. All of Hill's mathematical and astronomical research was incorporated in The Collected Mathematical Works of George William Hill. This work, containing a preface in French by Poincare, was published in 4 large volumes by the Carnegie Institution of Washington in 1905.

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 ...

Archaeoastronomy as a Tool for Understanding Celestial Phenomena

Science.gov (United States)

Koufos, S.; Chatzichristou, E.

2017-09-01

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

Collaborative learning for public relations: Frame analysis in training for spokespersons

Directory of Open Access Journals (Sweden)

Sergio Álvarez Sánchez

2018-05-01

Full Text Available The collaborative model for learning implies students forming teams in order to reach a common goal. The objectives of this research are both exploring the impact of the collaborative model over the performance of those learners who study contents related to the formation of spokespersons for organizations; and evaluating the potential of frame analysis as a content for training in public relations. To delve into those issues, a case study exercise was administered to six groups of students of the “Training for Spokespersons” subject, consisting of analyzing the audiovisual intervention of a spokesperson talking on behalf of a strike commitee, and answering questions about target publics and frames of reference. The exercise succeeded in helping the students understand the role of emotional communication; however, they still got slightly confused about frame analysis and its link with the concept of social norm. For future research, it becomes necessary to focus on moving even more away from the classic master classes, as well as using cases that students can feel closer to their interests. With respect to frame analysis, the results encourage the teaching of more precise classifications in terms of general frames about a certain topic, and specific frames about particular situations.

Transformative decision rules, permutability, and non-sequential framing of decision problems

NARCIS (Netherlands)

Peterson, M.B.

2004-01-01

The concept of transformative decision rules provides auseful tool for analyzing what is often referred to as the`framing', or `problem specification', or `editing' phase ofdecision making. In the present study we analyze a fundamentalaspect of transformative decision rules, viz. permutability. A

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

OpenAIRE

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

2009-01-01

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

Frames and outer frames for Hilbert C^*-modules

OpenAIRE

Arambašić, Ljiljana; Bakić, Damir

2015-01-01

The goal of the present paper is to extend the theory of frames for countably generated Hilbert $C^*$-modules over arbitrary $C^*$-algebras. In investigating the non-unital case we introduce the concept of outer frame as a sequence in the multiplier module $M(X)$ that has the standard frame property when applied to elements of the ambient module $X$. Given a Hilbert $\\A$-module $X$, we prove that there is a bijective correspondence of the set of all adjointable surjections from the generalize...

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

Directory of Open Access Journals (Sweden)

Suleiman Musa

2017-05-01

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

Weather Test Reference Year of Greenland

DEFF Research Database (Denmark)

Kragh, Jesper; Pedersen, Frank; Svendsen, Svend

2005-01-01

the construction of two test reference years of Greenland used in the work of establishing new energy frame for the coming building code of Greenland. The first test reference year is constructed using measurements of climatic parameters from the town Nuuk located in the southwestern part of Greenland. The second...... test reference year is constructed using measurements from the town Uummannaq located in the north part of Greenland on the west coast. The construction of the test reference years fulfills the procedures described in the standard EN ISO 15927-4 using the following main weather parameters: Dry bulb...... temperature, global radiation, relative humidity and mean wind speed. To construct the test reference years a program called REFYEAR was developed in MatLab. REFYEAR automatically constructs the test reference year using an input file containing the climatic measurements. The two constructed test reference...

How Managers Can Create Value from Strategic Framing of Social Media

DEFF Research Database (Denmark)

Rydén, Pernille; Ringberg, Torsten; Wilke, Ricky

2015-01-01

these frames influence what the manager will consider as the optimal use of social media for a given situation. More specifically, we identify six conceptualizations of social media, of which the first three regard social media as tactical tools for enhancing communication to and from end users......Strategic framing of social media tends to refer to the use of different platforms for marketingtactical purposes. This conceptual paper advances the fields of Business-to-Consumer marketing and strategic management by demonstrating how social media become conceptually framed and, in turn, how....... Such conceptualizations prevent the use of social media as strategic tools and thereby limits a strategically relevant and - for consumers - more meaningful engagement, thereby reducing potential customer value.The other three conceptualizations, we identify, regard social media in gradually more disruptive ways...

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

A FORTRAN version implementation of block adjustment of CCD frames and its preliminary application

Science.gov (United States)

Yu, Y.; Tang, Z.-H.; Li, J.-L.; Zhao, M.

2005-09-01

A FORTRAN version implementation of the block adjustment (BA) of overlapping CCD frames is developed and its flowchart is shown. The program is preliminarily applied to obtain the optical positions of four extragalactic radio sources. The results show that because of the increase in the number and sky coverage of reference stars the precision of optical positions with BA is improved compared with the single CCD frame adjustment.

Burnham's celestial handbook. An observer's guide to the universe beyond the solar system. Volume 3. Pavo through Vulpecula

International Nuclear Information System (INIS)

Burnham, R. Jr.

1978-01-01

This volume of the Celestial Handbook treats the constellations alphabetically from Pavo through Vulpecula. For each it lists double and multiple stars, variable stars, and star clusters, nebulae, and galaxies with positions, magnitudes, etc. It also presents descriptive notes concerning some of the objects; these include history, mythology, and poetical allusions, as well as scientific information

On frame multiresolution analysis

DEFF Research Database (Denmark)

Christensen, Ole

2003-01-01

We use the freedom in frame multiresolution analysis to construct tight wavelet frames (even in the case where the refinable function does not generate a tight frame). In cases where a frame multiresolution does not lead to a construction of a wavelet frame we show how one can nevertheless...

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

OpenAIRE

Eymork, Tania Patricia

2012-01-01

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

Effects of Alternative Framing on the Publics Perceived Importance of Environmental Conservation

Directory of Open Access Journals (Sweden)

Amanda E Sorensen

2015-05-01

Full Text Available Effective communication of science to the general public is important for numerous reasons, including support for policy, funding, informed public decision making, among others. Prior research has found that scientists participating in public policy and public communication must frame their communication efforts in order to connect with audiences. A frame is the mechanism that individuals use to understand and interpret the world around them. Framing can encourage specific interpretations and reference points for a particular issue or event; especially when meaning is negotiated between the media and public audiences. In this study, we looked at the effect of framing within an environmental conservation context. To do this we had survey respondents rank common issues, among them being environmental conservation, from most important to least important for the government to address. We framed environmental conservation using three synonymous terms (environmental security, ecosystem services, and environmental quality to assess whether there was an effect on rankings dependent on how we framed environmental conservation. We also investigated the effect of individuals’ personality characteristics (identity frame on those environmental conservation rankings. We found that individuals who self-identified as environmentalist were positively associated with ranking highly (most important environmental conservation when it was framed as either environmental quality or ecosystem services, but not when it was framed as environmental security. Conversely, those individuals who did not rank themselves highly as self-identified environmentalists were positively associated with environmental conservation when it was framed as environmental security. This research suggests that framing audience specific messages can engender audience support in hot-button issues such as environmental conservation and climate change.

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…

Causal anomalies and the case for a preferred referential frame

International Nuclear Information System (INIS)

Martins, R.A.

1984-01-01

A theoretical argument supporting the idea that in some physical situations compatible with the general theory of relativity one may have very good reasons for choosing one particular reference frame in a locally Minkowskian space-time-that is, in a case where special relativity is supposed to hold, is described. (L.C.) [pt

Justice orientation as a moderator of the framing effect on procedural justice perception.

Science.gov (United States)

Sasaki, Hiroyuki; Hayashi, Yoichiro

2014-01-01

Justice orientation is a justice-relevant personality trait, which is referred to as the tendency to attend to fairness issues and to internalize justice as a moral virtue. This study examined the moderating role of justice orientation in the relationship between justice perception and response to a decision problem. The authors manipulated procedural justice and the outcome valence of the decision frame within a vignette, and measured justice orientation of 174 Japanese participants. As hypothesized, the results indicated an interaction between procedural justice and framing manipulation, which was moderated by individual differences in justice orientation. In negative framing, justice effects were larger for individuals with high rather than low justice orientation. The results are explained from a social justice perspective, and the contributions and limitations of this study are also discussed with respect to our sample and framing manipulation.

Network-based H.264/AVC whole frame loss visibility model and frame dropping methods.

Science.gov (United States)

Chang, Yueh-Lun; Lin, Ting-Lan; Cosman, Pamela C

2012-08-01

We examine the visual effect of whole frame loss by different decoders. Whole frame losses are introduced in H.264/AVC compressed videos which are then decoded by two different decoders with different common concealment effects: frame copy and frame interpolation. The videos are seen by human observers who respond to each glitch they spot. We found that about 39% of whole frame losses of B frames are not observed by any of the subjects, and over 58% of the B frame losses are observed by 20% or fewer of the subjects. Using simple predictive features which can be calculated inside a network node with no access to the original video and no pixel level reconstruction of the frame, we developed models which can predict the visibility of whole B frame losses. The models are then used in a router to predict the visual impact of a frame loss and perform intelligent frame dropping to relieve network congestion. Dropping frames based on their visual scores proves superior to random dropping of B frames.

Framing Failures in Wood-Frame Hip Roofs under Extreme Wind Loads

Directory of Open Access Journals (Sweden)

Sarah A. Stevenson

2018-02-01

Full Text Available Wood-frame residential roof failures are among the most common and expensive types of wind damage. Hip roofs are commonly understood to be more resilient during extreme wind in relation to gable roofs. However, inspection of damage survey data from recent tornadoes has revealed a previously unstudied failure mode in which hip roofs suffer partial failure of the framing structure. In the current study, evidence of partial framing failures and statistics of their occurrence are explored and discussed, while the common roof design and construction practice are reviewed. Two-dimensional finite element models are developed to estimate the element-level load effects on hip roof trusses and stick-frame components. The likelihood of failure in each member is defined based on relative demand-to-capacity ratios. Trussed and stick-frame structures are compared to assess the relative performance of the two types of construction. The present analyses verify the common understanding that toenailed roof-to-wall connections are likely to be the most vulnerable elements in the structure of a wood-frame hip roof. However, the results also indicate that certain framing members and connections display significant vulnerability under the same wind uplift, and the possibility of framing failure is not to be discounted. Furthermore, in the case where the roof-to-wall connection uses hurricane straps, certain framing members and joints become the likely points of failure initiation. The analysis results and damage survey observations are used to expand the understanding of wood-frame residential roof failures, as they relate to the Enhanced Fujita Scale and provide assessment of potential gaps in residential design codes.

When message-frame fits salient cultural-frame, messages feel more persuasive

OpenAIRE

Uskul, Ayse K.; Oyserman, Daphna

2010-01-01

The present study examines the persuasive effects of tailored health messages comparing those tailored to match (versus not match) both chronic cultural frame and momentarily salient cultural frame. Evidence from two studies (Study 1: n = 72 European Americans; Study 2: n = 48 Asian Americans) supports the hypothesis that message persuasiveness increases when chronic cultural frame, health message tailoring and momentarily salient cultural frame all match. The hypothesis was tested using a me...

The Frame Constraint on Experimentally Elicited Speech Errors in Japanese

Science.gov (United States)

Saito, Akie; Inoue, Tomoyoshi

2017-01-01

The so-called syllable position effect in speech errors has been interpreted as reflecting constraints posed by the frame structure of a given language, which is separately operating from linguistic content during speech production. The effect refers to the phenomenon that when a speech error occurs, replaced and replacing sounds tend to be in the…

Redes alternativas de comunicación, framing y la construcción del poder político (Alternative communication networks, framing and construction of political power

Directory of Open Access Journals (Sweden)

Mayra Martínez Avidad

2011-12-01

Full Text Available El objetivo del presente artículo es analizar el papel de las redes alternativas de comunicación en la construcción del poder político a través del proceso de framing o enmarcado. En los últimos años, la capacidad del público para producir (nuestros propios mensajes que potencialmente desafíen los encuadres fijados por la elite política se ha expandido enormemente con la llegada de Internet y las comunicaciones móviles. En este sentido, las redes virtuales son importantes porque pueden aumentar la capacidad de las masas para comunicarse entre sí transformando los marcos de referencia individuales en marcos interpretativos de carácter colectivo.The aim of this paper is to analyze the role of alternative communication networks in the construction of political power through the process of framing. In recent years, the ability of the public to produce (our own messages that potentially challenge those frames established by political elites has been importantly expanded by the advent of Internet and mobile communications. In this sense, virtual networks are important because they can influence the capacity of masses to communicate with each other transforming individual frames of reference into collective interpretative frames.

Value Framing: A Prelude to Software Problem Framing

NARCIS (Netherlands)

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

2004-01-01

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

Message Framing in Vaccine Communication: A Systematic Review of Published Literature.

Science.gov (United States)

Penţa, Marcela A; Băban, Adriana

2018-03-01

Suboptimal vaccination rates are a significant problem in many countries today, in spite of improved access to vaccine services. As a result, there has been a recent expansion of research on how best to communicate about vaccines. The purpose of the present article is to provide an updated review of published, peer-reviewed empirical studies that examined the effectiveness of gain versus loss framing (i.e., goal framing) in the context of vaccine communication. To locate studies, we examined the reference list from the previous meta-analytic review (O'Keefe & Nan, 2012), and we conducted systematic searches across multiple databases. We included 34 studies in the qualitative synthesis. The relative effectiveness of goal-framed vaccine messages was often shown to depend on characteristics of the message recipient, perceived risk, or situational factors, yet most effects were inconsistent across studies, or simply limited by an insufficient number of studies. Methodological characteristics and variations are noted and discussed. The review points to several directions concerning moderators and mediators of framing effects where additional rigorous studies would be needed.

Filtering SVM frame-by-frame binary classification in a detection framework

NARCIS (Netherlands)

Betancourt Arango, A.; Morerio, P.; Marcenaro, L.; Rauterberg, G.W.M.; Regazzoni, C.S.

2015-01-01

Classifying frames, or parts of them, is a common way of carrying out detection tasks in computer vision. However, frame by frame classification suffers from sudden significant variations in image texture, colour and luminosity, resulting in noise in the extracted features and consequently in the

New characterizations of fusion frames (frames of subspaces)

Indian Academy of Sciences (India)

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

Extending the ICRF to Higher Radio Frequencies: 24 and 43 GHz Astrometry

Science.gov (United States)

Jacobs, Christopher S.; Charlot, Patrick; Fomalont, Ed B.; Gordon, David; Lanyi, Gabor E.; Ma, Chopo; Naudet, Charles J.; Sovers, Ojars J.; Zhang, Liwei D.; Kq VLBI Survey Collaboration

2004-06-01

Celestial reference frames have been constructed at K-band (24 GHz) and Q-band (43 GHz) based on VLBI astrometric survey observations of active galactic nuclei. Five VLBA observing sessions covered the full 24 hours of right ascension and declinations down to -44°. K-band's 230 sources have median formal position uncertainties of 150 and 290 μas in α cos δ and δ, respectively; the corresponding uncertainties for 132 Q-band sources are 215 and 360 μas, respectively. K-band weighted RMS (WRMS) residuals were 33 ps and 48 fs/s in delay and rate, respectively. Comparison of the K-band frame to the S/X-band ICRF shows WRMS agreement of 330 and 590 μas in α cos δ and δ, respectively. The motivations for extending the ICRF to higher frequencies are to use more compact sources to construct a more stable frame, to provide phase calibrators, and to support spacecraft navigation at Ka-band.

Immune reactivity of candidate reference materials

NARCIS (Netherlands)

Fernandez-Rivas, Montserrat; Aalbers, Marja; Fötisch, Kay; de Heer, Pleuni; Notten, Silla; Vieths, Stefan; van Ree, Ronald

2006-01-01

Immune reactivity is a key issue in the evaluation of the quality of recombinant allergens as potential reference materials. Within the frame of the CREATE project, the immune reactivity of the natural and recombinant versions of the major allergens of birch pollen (Bet v 1), grass pollen (Phl p 1

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

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

International Nuclear Information System (INIS)

Svensson, Ola; Salo, Ilkka

2004-11-01

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

Equilibrium positions on stationary orbits and planetary principal inertia axis orientations for the Solar System

Science.gov (United States)

Romero, Pilar; Barderas, Gonzalo; Mejuto, Javier

2018-05-01

We present a qualitative analysis in a phase space to determine the longitudinal equilibrium positions on the planetary stationary orbits by applying an analytical model that considers linear gravitational perturbations. We discuss how these longitudes are related with the orientation of the planetary principal inertia axes with respect to their Prime Meridians, and then we use this determination to derive their positions with respect to the International Celestial Reference Frame. Finally, a numerical analysis of the non-linear effects of the gravitational fields on the equilibrium point locations is developed and their correlation with gravity field anomalies shown.

Framing Gangnam Style

Directory of Open Access Journals (Sweden)

Hyunsun Catherine Yoon

2017-08-01

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

Hunting down frame shifts: Ecological analysis of diverse functional gene sequences

Directory of Open Access Journals (Sweden)

Michal eStrejcek

2015-11-01

Full Text Available Functional gene ecological analyses using amplicon sequencing can be challenging as translated sequences are often burdened with shifted reading frames. The aim of this work was to evaluate several bioinformatics tools designed to correct errors which arise during sequencing in an effort to reduce the number of frame-shifts (FS. Genes encoding for alpha subunits of biphenyl (bphA and benzoate (benA dioxygenases were used as model sequences. FrameBot, a FS correction tool, was able to reduce the number of detected FS to zero. However, up to 43.1% of sequences were discarded by FrameBot as non-specific targets. Therefore, we proposed a de novo mode of FrameBot for FS correction, which works on a similar basis as common chimera identifying platforms and is not dependent on reference sequences. By nature of FrameBot de novo design, it is crucial to provide it with data as error free as possible. We tested the ability of several publicly available correction tools to decrease the number of errors in the data sets. The combination of Maximum Expected Error (MEE filtering and single linkage pre-clustering (SLP proved the most efficient read procession. Applying FrameBot de novo on the processed data enabled analysis of BphA sequences with minimal losses of potentially functional sequences not homologous to those previously known. This experiment also demonstrated the extensive diversity of dioxygenases in soil. A script which performs FrameBot de novo is presented in the supplementary material to the study and the tool was implemented into FunGene Pipeline available at http://fungene.cme.msu.edu/FunGenePipeline/ and https://github.com/rdpstaff/Framebot.

Pneumafil casing blower through moving reference frame (MRF) - A CFD simulation

Science.gov (United States)

Manivel, R.; Vijayanandh, R.; Babin, T.; Sriram, G.

2018-05-01

In this analysis work, the ring frame of Pneumafil casing blower of the textile mills with a power rating of 5 kW have been simulated using Computational Fluid Dynamics (CFD) code. The CFD analysis of the blower is carried out in Ansys Workbench 16.2 with Fluent using MRF solver settings. The simulation settings and boundary conditions are based on literature study and field data acquired. The main objective of this work is to reduce the energy consumption of the blower. The flow analysis indicated that the power consumption is influenced by the deflector plate orientation and deflector plate strip situated at the outlet casing of the blower. The energy losses occurred in the blower is due to the recirculation zones formed around the deflector plate strip. The deflector plate orientation is changed and optimized to reduce the energy consumption. The proposed optimized model is based on the simulation results which had relatively lesser power consumption than the existing and other cases. The energy losses in the Pneumafil casing blower are reduced through CFD analysis.

Frames for undergraduates

CERN Document Server

Han, Deguang; Larson, David; Weber, Eric

2007-01-01

Frames for Undergraduates is an undergraduate-level introduction to the theory of frames in a Hilbert space. This book can serve as a text for a special-topics course in frame theory, but it could also be used to teach a second semester of linear algebra, using frames as an application of the theoretical concepts. It can also provide a complete and helpful resource for students doing undergraduate research projects using frames. The early chapters contain the topics from linear algebra that students need to know in order to read the rest of the book. The later chapters are devoted to advanced topics, which allow students with more experience to study more intricate types of frames. Toward that end, a Student Presentation section gives detailed proofs of fairly technical results with the intention that a student could work out these proofs independently and prepare a presentation to a class or research group. The authors have also presented some stories in the Anecdotes section about how this material has moti...

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

Science.gov (United States)

Chen, Shao-Guang

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

Standard Relativistic Reference Systems and the IAU Framework

Science.gov (United States)

Soffel, Michael H.

2009-05-01

The classical post-Newtonian (PN) framework is formulated in one single reference system. In a series of papers Damour, Soffel and Xu laid the foundations for a new improved PN framework dealing with the celestial mechanical problem of N gravitationally interacting rotating bodies of arbitrary shape and the problem of astronomical reference systems. In the DSX-framework a total of N+1 reference systems with corresponding coordinates is introduced in the N-body problem: a global one covering the entire model manifold where the translational equations of motion are formulated and one local system attached to each of the N bodies that is co-moving with the body under consideration. In each of these systems the metric tensor is assumed to be of a special form determined by two potentials: a scalar and a vector potential. Theorems are given for the transformations between local and global coordinates and metric potentials. In each of the local systems outside the local body the metric potentials are expressed in terms of Blanchet-Damour mass- and spin-multipole moments. The talk first introduces the original DSX formalism and then concentrates on IAU resolutions related with it. Finally, the formalism is extended to include also effects from the cosmic expansion. The influence of the Hubble expansion on the dynamics of the solar system is explicitly discussed in some detail.

On Framing

DEFF Research Database (Denmark)

Peder Pedersen, Claus

2018-01-01

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

The effect of abstract versus concrete framing on judgments of biological and psychological bases of behavior.

Science.gov (United States)

Kim, Nancy S; Johnson, Samuel G B; Ahn, Woo-Kyoung; Knobe, Joshua

2017-01-01

Human behavior is frequently described both in abstract, general terms and in concrete, specific terms. We asked whether these two ways of framing equivalent behaviors shift the inferences people make about the biological and psychological bases of those behaviors. In five experiments, we manipulated whether behaviors are presented concretely (i.e. with reference to a specific person, instantiated in the particular context of that person's life) or abstractly (i.e. with reference to a category of people or behaviors across generalized contexts). People judged concretely framed behaviors to be less biologically based and, on some dimensions, more psychologically based than the same behaviors framed in the abstract. These findings held true for both mental disorders (Experiments 1 and 2) and everyday behaviors (Experiments 4 and 5), and yielded downstream consequences for the perceived efficacy of disorder treatments (Experiment 3). Implications for science educators, students of science, and members of the lay public are discussed.

Eckart frame vibration-rotation Hamiltonians: Contravariant metric tensor

International Nuclear Information System (INIS)

Pesonen, Janne

2014-01-01

Eckart frame is a unique embedding in the theory of molecular vibrations and rotations. It is defined by the condition that the Coriolis coupling of the reference structure of the molecule is zero for every choice of the shape coordinates. It is far from trivial to set up Eckart kinetic energy operators (KEOs), when the shape of the molecule is described by curvilinear coordinates. In order to obtain the KEO, one needs to set up the corresponding contravariant metric tensor. Here, I derive explicitly the Eckart frame rotational measuring vectors. Their inner products with themselves give the rotational elements, and their inner products with the vibrational measuring vectors (which, in the absence of constraints, are the mass-weighted gradients of the shape coordinates) give the Coriolis elements of the contravariant metric tensor. The vibrational elements are given as the inner products of the vibrational measuring vectors with themselves, and these elements do not depend on the choice of the body-frame. The present approach has the advantage that it does not depend on any particular choice of the shape coordinates, but it can be used in conjunction with all shape coordinates. Furthermore, it does not involve evaluation of covariant metric tensors, chain rules of derivation, or numerical differentiation, and it can be easily modified if there are constraints on the shape of the molecule. Both the planar and non-planar reference structures are accounted for. The present method is particular suitable for numerical work. Its computational implementation is outlined in an example, where I discuss how to evaluate vibration-rotation energies and eigenfunctions of a general N-atomic molecule, the shape of which is described by a set of local polyspherical coordinates

Stellar aberration correction and thermoelastic compensation of Swarm μASC attitude observations: A comment to the Express Letter “Mysterious misalignments between geomagnetic and stellar reference frames seen in CHAMP and Swarm satellite measurements”, by Stefan Maus

DEFF Research Database (Denmark)

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

2017-01-01

. However, comparison of the Inter Boresight Angle shows a relative attitude variation between the μASC Camera Head Units. These misalignments between Camera Head Units and a geomagnetic reference frame cannot be explained by incorrect aberration correction (as theorized by Maus). Herceg et al. found them...... and clean from any variation caused by thermoelastic effects....

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

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.

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

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

Serialising languages: Satellite-framed, verb-framed or neither ...

African Journals Online (AJOL)

The diversity in the coding of the core schema of motion, i.e., Path, has led to a traditional typology of languages into verb-framed and satellite-framed languages. In the former Path is encoded in verbs and in the latter it is encoded in non-verb elements that function as sisters to co-event expressing verbs such as manner ...

Comparisons of selected frame constructions considering effects of rock bursts and earthquakes. [Poland

Energy Technology Data Exchange (ETDEWEB)

Trojan, Z.; Lipski, Z.; Raczek, R.

1985-01-01

Methods for assessing apartment buildings with frames made of reinforced concrete or steel elements situated above coal mines in Upper Silesia are analyzed. Six buildings from 13.5 m to 37.8 m high are analyzed. Methods for design of earthquake-resistant buildings and buildings constructed in areas affected by underground coal mining are compared. Safety standards used in Israel, the FRG, the USSR, Czechoslovakia and Australia are compared to standards used in Poland for buildings in areas affected by underground mining in Upper Silesia. Loads on a building frame during a shock (caused by mining) with an energy of 10/sup 9/ J are analyzed. Force of inertia and bending moment in the building frame is calculated. Investigation results are shown in 3 tables and in a diagram. Recommendations for methods of calculating bending moment in frames of buildings affected by shocks caused by underground coal mining are made. 11 references.

ostglacial rebound from VLBI Geodesy: On Establishing Vertical Reference

Science.gov (United States)

Argus, Donald .

1996-01-01

I propose that a useful reference frame for vertical motions is that found by minimizing differences between vertical motions observed with VLBI [Ma and Ryan, 1995] and predictions from postglacial rebound predictions [Peltier, 1995].

New International Agreements About Space Techniques Among Argentina, China and France

Science.gov (United States)

Pacheco, A. M.; Podestá, R.; Actis, E.; Adarvez, S.; Quinteros, J.; Li, J.; Saunier, J.; Podestá, F.; Ramos, F.; Aguilera, J.; Sosa, G.; Hauser, D.

2018-01-01

The International Earth Rotation and Reference Systems (IERS) is in charge of defining and materializing celestial reference systems (ICRS - ICRF) and terrestrial reference systems (ITRS - ITRF). In order to perform this task it uses data from the following techniques: Very Long Baseline Interferometry (VLBI), Satellite Laser Ranging (SLR), Global Navigation Satellite System (GNSS) and Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS). Nowadays, the Observatorio Astronómico Félix Aguilar (OAFA) has two instruments with these advanced techniques: SLR and a permanent GNSS station. In the nearby future a 40 m diameter radio telescope will be available that will be operated in VLBI mode along with a DORIS buoy which will be co-localized with a SLR telescope and GNSS antennas. In this way OAFA will become a zero station, first class, of the ITRF 2014 frame.

Separating electroweak and strong interactions in Drell-Yan processes at LHC: leptons angular distributions and reference frames

International Nuclear Information System (INIS)

Richter-Was, E.; Was, Z.

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 interaction ones for the benefit of the interpretation of the measurements. Our study exploits properties of single gluon emission matrix elements which are clearly visible if a conveniently chosen form of their representation is used. We rely also on distributions obtained from matrix element based Monte Carlo generated samples of events with two leptons and up to two additional partons in test samples. Incoming colliding protons' partons are distributed accordingly to PDFs and are strictly collinear to the corresponding beams. (orig.)

Writing more informative letters of reference.

Science.gov (United States)

Wright, Scott M; Ziegelstein, Roy C

2004-05-01

Writing a meaningful and valuable letter of reference is not an easy task. Several factors influence the quality of any letter of reference. First, the accuracy and reliability of the writer's impressions and judgment depend on how well he knows the individual being described. Second, the writer's frame of reference, which is determined by the number of persons at the same level that he has worked with, will impact the context and significance of his beliefs and estimations. Third, the letter-writing skills of the person composing the letter will naturally affect the letter. To support the other components of a candidate's application, a letter of reference should provide specific examples of how an individual's behavior or attitude compares to a reference group and should assess "intangibles" that are hard to glean from a curriculum vitae or from test scores. This report offers suggestions that should help physicians write more informative letters of reference.

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...

When message-frame fits salient cultural-frame, messages feel more persuasive.

Science.gov (United States)

Uskul, Ayse K; Oyserman, Daphna

2010-03-01

The present study examines the persuasive effects of tailored health messages comparing those tailored to match (versus not match) both chronic cultural frame and momentarily salient cultural frame. Evidence from two studies (Study 1: n = 72 European Americans; Study 2: n = 48 Asian Americans) supports the hypothesis that message persuasiveness increases when chronic cultural frame, health message tailoring and momentarily salient cultural frame all match. The hypothesis was tested using a message about health risks of caffeine consumption among individuals prescreened to be regular caffeine consumers. After being primed for individualism, European Americans who read a health message that focused on the personal self were more likely to accept the message-they found it more persuasive, believed they were more at risk and engaged in more message-congruent behaviour. These effects were also found among Asian Americans who were primed for collectivism and who read a health message that focused on relational obligations. The findings point to the importance of investigating the role of situational cues in persuasive effects of health messages and suggest that matching content to primed frame consistent with the chronic frame may be a way to know what to match messages to.

MR-guided data framing for PET motion correction in simultaneous MR–PET: A preliminary evaluation

Energy Technology Data Exchange (ETDEWEB)

Ullisch, M.G., E-mail: m.ullisch@fz-juelich.de [Institute of Neuroscience and Medicine (INM-4), Forschungszentrum Jülich GmbH (Germany); Scheins, J.; Weirich, C.; Rota Kops, E.; Celik, A.; Tellmann, L.; Stöcker, T.; Herzog, H.; Shah, N.J. [Institute of Neuroscience and Medicine (INM-4), Forschungszentrum Jülich GmbH (Germany)

2013-02-21

Head motion can significantly degrade image quality of static and dynamic Positron Emission Tomography (PET) of the human brain. One method to regain acceptable image quality in the presence of motion is to include the correction for motion in the reconstruction process. When applying motion correction, the PET data can be segmented into discrete parts of similar head position, referred to as frames. This framing of the data can reduce the computational overhead necessary for motion correction during the reconstruction process by reducing the number of discrete head positions which have to be accounted for. Here a framing algorithm is presented which minimises residual motion in the framed data, while taking full advantage of the additional information provided by Magnetic Resonance Imaging (MRI) in a simultaneous MR–PET acquisition. In the work presented here information on motion is derived from EPI sequences acquired simultaneously with the PET data. A comparison to images reconstructed with regular framing show a more clearly delineated cortex due to increased contrast between grey matter and white matter. This improvement in image quality is achieved as well as a reduction in the number of frames, thereby reducing the reconstruction time. Preliminary data indicates an efficient reduction of residual intra-frame motion compared to regular framing.

Einstein and Jordan frames reconciled: A frame-invariant approach to scalar-tensor cosmology

International Nuclear Information System (INIS)

Catena, Riccardo; Pietroni, Massimo; Scarabello, Luca

2007-01-01

Scalar-tensor theories of gravity can be formulated in different frames, most notably, the Einstein and the Jordan one. While some debate still persists in the literature on the physical status of the different frames, a frame transformation in scalar-tensor theories amounts to a local redefinition of the metric, and then should not affect physical results. We analyze the issue in a cosmological context. In particular, we define all the relevant observables (redshift, distances, cross sections, ...) in terms of frame-independent quantities. Then, we give a frame-independent formulation of the Boltzmann equation, and outline its use in relevant examples such as particle freeze-out and the evolution of the cosmic microwave background photon distribution function. Finally, we derive the gravitational equations for the frame-independent quantities at first order in perturbation theory. From a practical point of view, the present approach allows the simultaneous implementation of the good aspects of the two frames in a clear and straightforward way

column frame for design of reinforced concrete sway frames

African Journals Online (AJOL)

adminstrator

design of slender reinforced concrete columns in sway frames according .... concrete,. Ac = gross cross-sectional area of the columns. Step 3: Effective Buckling Length Factors. The effective buckling length factors of columns in a sway frame shall be computed by .... shall have adequate resistance to failure in a sway mode ...

Mapping university students’ epistemic framing of computational physics using network analysis

Directory of Open Access Journals (Sweden)

Madelen Bodin

2012-04-01

Full Text Available Solving physics problem in university physics education using a computational approach requires knowledge and skills in several domains, for example, physics, mathematics, programming, and modeling. These competences are in turn related to students’ beliefs about the domains as well as about learning. These knowledge and beliefs components are referred to here as epistemic elements, which together represent the students’ epistemic framing of the situation. The purpose of this study was to investigate university physics students’ epistemic framing when solving and visualizing a physics problem using a particle-spring model system. Students’ epistemic framings are analyzed before and after the task using a network analysis approach on interview transcripts, producing visual representations as epistemic networks. The results show that students change their epistemic framing from a modeling task, with expectancies about learning programming, to a physics task, in which they are challenged to use physics principles and conservation laws in order to troubleshoot and understand their simulations. This implies that the task, even though it is not introducing any new physics, helps the students to develop a more coherent view of the importance of using physics principles in problem solving. The network analysis method used in this study is shown to give intelligible representations of the students’ epistemic framing and is proposed as a useful method of analysis of textual data.

Weaving Hilbert space fusion frames

OpenAIRE

Neyshaburi, Fahimeh Arabyani; Arefijamaal, Ali Akbar

2018-01-01

A new notion in frame theory, so called weaving frames has been recently introduced to deal with some problems in signal processing and wireless sensor networks. Also, fusion frames are an important extension of frames, used in many areas especially for wireless sensor networks. In this paper, we survey the notion of weaving Hilbert space fusion frames. This concept can be had potential applications in wireless sensor networks which require distributed processing using different fusion frames...

Wavelet frames and their duals

DEFF Research Database (Denmark)

Lemvig, Jakob

2008-01-01

frames with good time localization and other attractive properties. Furthermore, the dual wavelet frames are constructed in such a way that we are guaranteed that both frames will have the same desirable features. The construction procedure works for any real, expansive dilation. A quasi-affine system....... The signals are then represented by linear combinations of the building blocks with coefficients found by an associated frame, called a dual frame. A wavelet frame is a frame where the building blocks are stretched (dilated) and translated versions of a single function; such a frame is said to have wavelet...... structure. The dilation of the wavelet building blocks in higher dimension is done via a square matrix which is usually taken to be integer valued. In this thesis we step away from the "usual" integer, expansive dilation and consider more general, expansive dilations. In most applications of wavelet frames...

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...

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.

Framing effects in medical situations: distinctions of attribute, goal and risky choice frames.

Science.gov (United States)

Peng, Jiaxi; Jiang, Yuan; Miao, Danmin; Li, Rui; Xiao, Wei

2013-06-01

To verify whether three different framing effects (risky choice, attribute and goal) exist in simulated medical situations and to analyse any differences. Medical decision-making problems were established, relating to medical skill evaluation, patient compliance and a selection of treatment options. All problems were described in positive and negative frame conditions. Significantly more positive evaluations were made if the doctor's medical records were described as 'of 100 patients, 70 patients became better' compared with those described as 'of 100 patients, 30 patients didn't become better'. Doctor's advice described in a negative frame resulted in significantly more decisions to comply, compared with advice described in a positive frame. Treatment options described in terms of survival rates resulted in significantly more adventurous choices compared with options described in terms of mortality rates. Decision-making reversal appeared in the risky choice and attribute frames, but not the goal frame. Framing effects were shown to exist in simulated medical situations, but there were significant differences among the three kinds of such effects.

Message framing and perinatal decisions.

Science.gov (United States)

Haward, Marlyse F; Murphy, Ryan O; Lorenz, John M

2008-07-01

The purpose of this study was to explore the effect of information framing on parental decisions about resuscitation of extremely premature infants. Secondary outcomes focused on elucidating the impact of other variables on treatment choices and determining whether those effects would take precedence over any framing effects. This confidential survey study was administered to adult volunteers via the Internet. The surveys depicted a hypothetical vignette of a threatened delivery at gestational age of 23 weeks, with prognostic outcome information framed as either survival with lack of disability (positive frame) or chance of dying and likelihood of disability among survivors (negative frame). Participants were randomly assigned to receive either the positively or negatively framed vignette. They were then asked to choose whether they would prefer resuscitation or comfort care. After completing the survey vignette, participants were directed to a questionnaire designed to test the secondary hypothesis and to explore possible factors associated with treatment decisions. A total of 146 subjects received prognostic information framed as survival data and 146 subjects received prognostic information framed as mortality data. Overall, 24% of the sample population chose comfort care and 76% chose resuscitation. A strong trend was detected toward a framing effect on treatment preference; respondents for whom prognosis was framed as survival data were more likely to elect resuscitation. This framing effect was significant in a multivariate analysis controlling for religiousness, parental status, and beliefs regarding the sanctity of life. Of these covariates, only religiousness modified susceptibility to framing; participants who were not highly religious were significantly more likely to be influenced to opt for resuscitation by the positive frame than were participants who were highly religious. Framing bias may compromise efforts to approach prenatal counseling in a

100-ps framing-camera tube

International Nuclear Information System (INIS)

Kalibjian, R.

1978-01-01

The optoelectronic framing-camera tube described is capable of recording two-dimensional image frames with high spatial resolution in the <100-ps range. Framing is performed by streaking a two-dimensional electron image across narrow slits. The resulting dissected electron line images from the slits are restored into framed images by a restorer deflector operating synchronously with the dissector deflector. The number of framed images on the tube's viewing screen equals the number of dissecting slits in the tube. Performance has been demonstrated in a prototype tube by recording 135-ps-duration framed images of 2.5-mm patterns at the cathode. The limitation in the framing speed is in the external drivers for the deflectors and not in the tube design characteristics. Faster frame speeds in the <100-ps range can be obtained by use of faster deflection drivers

Lexically Allusive Content of Semantic Frames (Based on the Works of John Fowles

Directory of Open Access Journals (Sweden)

Aleksandra Aleksandrovna Akatova

2015-11-01

Full Text Available The semantic frame is a cognitive model, some mental structure that unites the world map and the thesaurus of a person, the hierarchy of meanings and values of the linguistic model of the world. Conceptual-cognitive content of a semantic frame includes three constituents: the reader, the author, and culture. The postmodernistic metatext, a vivid example of which is the metatext of John Fowles, is made of lexical-semantic frames, filled with allusions, general cultural precedent phenomena, cross-references, leitmotif lexemes. The frames of "freedom" and "game" exemplify integrated leitmotif of enclosed space, sea, theater, meta-theatre, god, god's imitations, magician (wizard, and fool. The application of a semantic frames method for the analysis of lexical-allusive elements in the works of John Fowles (The Aristos, The Magus, The Ebony Tower, Daniel Martin, French Lieutenant's Woman, A Maggot, Wormholes allowed to identify the net of allusive inclusions and arrange them into lexical-semantic frames, which helped to decode linguocultural metatext of the society and the individual (author. The interpretation of linguistic and cultural items in the text has lead to distinguishing the dominant frame of the metatext, that is "freedom". It is stated that creativity is freedom in action, responsibility is the condition for complete freedom, the path from the Fool to the Magician is the way from blindness of the stereotypes in the society to the intrinsic vision of internal freedom and unifying meaning of existence.

Veja o MST! - Um frame revelado

Directory of Open Access Journals (Sweden)

Adriana Maria Tenuta de Azevedo

2005-01-01

Full Text Available Esta é uma análise de duas reportagens jornalísticas publicadas em 3/04/2002, referentes a um único episódio: a invasão, liderada pelo Movimento dos Trabalhadores Sem-Terra (MST, da Fazenda Córrego da Ponte, situada em Buritis, Minas Gerais, de propriedade da família do então presidente Fernando Henrique Cardoso, ocorrida em 23/03/2002. Tal análise revela, no texto da Revista Veja (p. 46 a 50, a construção, principalmente através de recursos lexicais, de um determinado modelo cognitivo idealizado - frame - (Fauconnier, 1997 - subjacente à macro-estrutura do texto, o que não ocorre em relação à reportagem da Revista Isto é (p. 31 a 34. A existência de tal frame, compartilhada culturalmente por escritores e leitores, leva, por parte destes, a interpretações maniqueístas do evento sendo reportado.The present work is an analysis of two magazine reports referring to the episode of the invasion of Córrego da Ponte Farm, situated in Buritis, MG, which happened on March 23rd, 2002, led by the Landless Workers Movement (MST. Córrego da Ponte is property of the family of Fernando Henrique Cardoso (The president of Brazil at that time. The first of those reports (Veja Magazine, April 3rd, 2002, p. 46 to 50 is seen in details, since it presents elements of an idealized cognitive model - frame (Fauconnier, 1997 underlying the superstructure of the text. The existence of such frame, revealed by certain linguistic elements, especially the lexical choice, tends to raise dualistic interpretations of the socio-political event being reported. The second one (Isto é Magazine, edition 1696, April 03rd, 2002, p. 31 to 34 is taken as a differentiated parameter, for comparison to the analysis proposal for the first report.

First- and third-party ground truth for key frame extraction from consumer video clips

Science.gov (United States)

Costello, Kathleen; Luo, Jiebo

2007-02-01

Extracting key frames (KF) from video is of great interest in many applications, such as video summary, video organization, video compression, and prints from video. KF extraction is not a new problem. However, current literature has been focused mainly on sports or news video. In the consumer video space, the biggest challenges for key frame selection from consumer videos are the unconstrained content and lack of any preimposed structure. In this study, we conduct ground truth collection of key frames from video clips taken by digital cameras (as opposed to camcorders) using both first- and third-party judges. The goals of this study are: (1) to create a reference database of video clips reasonably representative of the consumer video space; (2) to identify associated key frames by which automated algorithms can be compared and judged for effectiveness; and (3) to uncover the criteria used by both first- and thirdparty human judges so these criteria can influence algorithm design. The findings from these ground truths will be discussed.

Conformal frame dependence of inflation

International Nuclear Information System (INIS)

Domènech, Guillem; Sasaki, Misao

2015-01-01

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

Conformal frame dependence of inflation

Energy Technology Data Exchange (ETDEWEB)

Domènech, Guillem; Sasaki, Misao, E-mail: guillem.domenech@yukawa.kyoto-u.ac.jp, E-mail: misao@yukawa.kyoto-u.ac.jp [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)

2015-04-01

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

Center of Mass of Two or More Celestial Bodies as a Basis of Comets and «Black Holes» Mechanism