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Mobility is one of the most debated issues in the current discussion on transport policies and the climate change. Related indicators are the modal split, transport growth and travel time savings, used for travel behaviour evaluations. In official transport statistics, the modal split is generally used in two ways, according to the number of modal trips and to the modal trip length. Although they are usually used separately, we will show that they are directly connected, where the latter is a weighted version of the former. The introduction of the reference units of "person" and "day" overcomes the limitations of a trip-based definition and extends the ansatz to a mobility-based methodology, where all modal combinations can be considered. Empirical data analysis shows, that transport growth is founded on the increase of individual motorised transport at the disadvantage of pedestrians, whereas other modes remain fairly stable. Daily travel time generally increases especially with individual motorised transport in comparison to non-motorised modes, which shows an inconsistency, for example, for some assumptions or approaches of travel time savings. The proposed methodology does not require any prior assumptions and provides therefore a simple and general applicability. The data analysis is based on national travel survey data from Germany, Switzerland, UK and USA from the 1970-ies up to 2018. One main result of the paper is a frame of reference for the relativity of mobility behaviour, which consistently connects these mobility indicators. • Using modal split definition and developed new functions for mobility behaviour. • Introducing reference units of person and time for a framework for mobility. • The frame of reference provides the basis for a new definition of mobility behaviour. • Further extensions are introduced to transport growth and travel time savings. • A systematic consistency and complementarity is obtained between the mobility indicators. [ABSTRACT FROM AUTHOR]

Reciprocal length contraction and time dilation, as enshrined in the Lorentz transformation, are the bulwark of the special relativity theory. Reciprocal time dilation is typically discussed (in the context of its apparent contradiction) and usually explained away as the result of differing synchronization in inertial reference frames and the relativity of simultaneity. Further, it is generally suggested that time is an abstract concept, and its perceptions may differ with context. However, we suggest that regarding length measurements no such abstraction can be envisaged. In this manuscript, we examine the reciprocal length contraction in detail to assess whether it leads to any contradiction. [ABSTRACT FROM AUTHOR]

In this work, the finite‐difference time‐domain (FDTD) method is employed to study electromagnetic problems with moving bodies in a moving system. The proposed approach consists in modeling objects with time‐varying positions and using the direct discretization of Maxwell's equations in space and time domains. Doppler effects are investigated for problems with moving observer, source, or reflector, in a moving frame. A distinction is also made between a high‐impedance or low‐impedance plane wave source in motion. The full‐wave electromagnetic simulations are compared with closed‐form equations that agree with wave theory. The proposed analysis shows that, for Doppler radars used every day, the motion of the Earth relative to the Cosmic Microwave Background has a negligible effect and only relative motions in the Earth frame are relevant. [ABSTRACT FROM AUTHOR]

Galileo's Principle of Relativity (GPR) states that the laws of mechanics are the same in any inertial frame of reference. By determining that all inertial reference frames are equivalent, this principle implies a relativity of motion. On the other hand, even considering the GPR as fundamental for mechanics, Isaac Newton introduces the concepts of absolute time and space and presents arguments, of a dynamic nature, in defense of absolute motion, justified by the differentiation between inertial and non-inertial reference frames. The Special Relativity Theory (SRT) criticizes the notions of absolute time and space, but preserves the privileged role of inertial reference frames in the description of the laws of nature. Only with the General Relativity Theory (GRT) is equivalence established between all references, regardless of their state of motion and, thus, the notion of absolute motion is overthrown. This work aims to discuss the main doubts and issues that arise when studying the aforementioned concepts, as well as to investigate the apparent dubiousness between the PRG and the absolute movement. [ABSTRACT FROM AUTHOR]

Copyright of Latin-American Journal of Physics Education is the property of Latin-American Physics Education Network and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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 n2, where n is the number of channels. This is more favorable than the full-quantum inelastic scattering calculations that scale as n3. 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. [ABSTRACT FROM AUTHOR]

Objective: The symmetry principle and the frame‐of‐reference perspective have each made contributions to improving the measurement of personality. Although each perspective is valuable in its own right, we argue that even greater improvement can be achieved through the combination of both. Therefore, the goal of the current article was to show the value of a combined lens‐model and frame‐of‐reference perspective. Method: We conducted a literature review to summarize relevant research findings that shed light on the interplay of both perspectives and developed an integrative model. Results: Based on the literature review and on theoretical grounds, we argue that a basic premise of the frame‐of‐reference literature––that personality items are open to interpretation and allow individuals to impose their own contextual framings––should be considered from a symmetry perspective. Unintended context‐specificity in items may "spread" to personality facets and domains, and thus, impact the symmetry of personality measures with other criteria. As the individuals´ frames‐of‐reference and (a)symmetric relationships are not always apparent, we term them as "hidden." Conclusions: The proposed combination of lens‐model and frame‐of‐reference perspectives provides further insights into current issues in personality research and uncovers important avenues for future research. [ABSTRACT FROM AUTHOR]

Successful performance on the water-level task, a common measure of spatial perception, requires adopting an environmental, rather than object-centered, spatial frame of reference. Use of this strategy has not been systematically studied in prepubertal children, a developmental period during which individual differences in spatial abilities start to emerge. In this study, children aged 8 to 11 reported their age and gender, completed a paper-and-pencil water-level task, and drew a map of their neighborhood to assess spontaneous choice of spatial frame of reference. Results showed a surprising lack of age or gender difference in water-level performance, but a significant effect of spatial frame of reference. Although they made up only a small portion of the sample, children who drew allocentric maps had the highest water-level score, with very high accuracy. These results suggest that children who adopt environmental-based reference frames when depicting their familiar environment may also use environmental-based reference frame strategies to solve spatial perception tasks, thereby facilitating highly accurate performance. [ABSTRACT FROM AUTHOR]

Management is mandatory for the effective use of increasingly expensive and complex information technology infrastructures. As a result of the evolution of information technology infrastructure management, multiple reference frameworks have emerged. In this article, in order to integrate the most used reference frameworks, a procedure is proposed that hierarchizes organizational capacities through a variable reduction method, obtaining an integrated process framework. Its application contributes to the management of information technology infrastructure management, facilitating alignment with the needs of each organization. [ABSTRACT FROM AUTHOR]

It has recently been shown that individuals residing in rural, indigenous communities rely on geocentric conceptualizations of space, e.g., north/south/east/west, even after they have shifted to a language that is known to favour egocentric conceptualizations, e.g., right/left. In this paper we explore how this combination works in practice by conducting a study in a previously non-investigated indigenous community of Mexico, the Ngiguas. We used a verbal localization task for community–scale relations. We filmed the responses of early bilinguals in Ngigua (Otomanguean) and in Spanish as well as of a control group of Spanish monolinguals from the same rural community. Statistical analysis of speech and co-speech gestures reveals that bilinguals favour geocentric gestures and direct pointing in both languages, associating them with topological and deictic terms. Against our predictions, Spanish monolinguals also use high rates of geocentric gestures that they frequently combine with cardinal terms. In sum, the Ngigua data show that geocentric conceptualizations can be transmitted to monolingual generations via co-speech gestures, including in a language where egocentric conceptualizations prevail in other settings. • A study of speech and co-speech gesture in a non-investigated population of bilinguals. • Conceptual convergence among the bilinguals based on the geocentric conceptualizations of the attrited language. • Geocentric linguistic conceptualizations are transmitted to monolingual speakers. • A stable relation to the environment may facilitate maintenance of geocentric conceptualizations. • Geocentric linguistic conceptualizations are resilient to literacy. [ABSTRACT FROM AUTHOR]

In this note, I apply Norton's (Philos Sci 79(2):207–232, 2012) distinction between idealizations and approximations to argue that the epistemic and inferential advantages often taken to accrue to minimal models (Batterman in Br J Philos Sci 53:21–38, 2002) could apply equally to approximations, including "infinite" ones for which there is no consistent model. This shows that the strategy of capturing essential features through minimality extends beyond models, even though the techniques for justifying this extended strategy remain similar. As an application I consider the justification and advantages of the approximation of a inertial reference frame in Norton's dome scenario (Philos Sci 75(5):786–798, 2008), thereby answering a question raised by Laraudogoitia (Synthese 190(14):2925–2941, 2013). [ABSTRACT FROM AUTHOR]

This study investigated the role of action constraints related to an object as regards allocentric distance estimation in extrapersonal space. In two experiments conducted in both real and virtual environments, participants intending to push a trolley had to estimate its distance from a target situated in front of them. The trolley was either empty (i.e., light) or loaded with books (i.e., heavy). The results showed that the estimated distances were larger for the heavy trolley than for the light one, and that the actual distance between the participants and the trolley moderated this effect. This data suggests that the potential mobility of an object used as a reference affects distance estimation in extrapersonal space. According to embodied perception theories, our results show that people perceive space in terms of constraints related to their potential actions. [ABSTRACT FROM AUTHOR]

Dynamic topography is a well-established consequence of global geodynamic models of mantle convection with horizontal dimensions of >1000 km and amplitudes up to 2 km. Such physical models guide the interpretation of geological records on equal dimensions. Continent-scale geological maps therefore serve as reference frames of choice to visualize erosion/non-deposition as a proxy for long-wavelength, low-amplitude vertical surface motion. At a resolution of systems or series, such maps display conformable and unconformable time boundaries traceable over hundreds to thousands of kilometres. Unconformable contact surfaces define the shape and size of time gap (hiatus) in millions of years based on the duration of time represented by the missing systems or series. Hiatus for a single system or series base datum diminishes laterally to locations (anchor points) where it is conformable at the mapped resolution; it is highly dependent upon scale. A comparison of hiatus area between two successive system or series boundaries yields changes in location, shape, size and duration, indicative of the transient nature of vertical surface motion. As a single-step technique, it serves as a quantitative proxy for palaeotopography that can be calibrated using other geological data. The tool magnifies the need for geological mapping at the temporal resolution of stages, matching process rates. The method has no resolving power within conformable regions (basins) but connects around them. When applied to marine seismic sections that relate to rock record, not to time, biostratigraphic and radiometric data from deep wells are needed before hiatus areas – that relate to time – can be mapped. [ABSTRACT FROM AUTHOR]

Abstract Reference-frame-independent quantum key distribution (RFI-QKD) has been demonstrated to be reliable and useful both in theories and experiments, which is intrinsically robust against slowly varying reference frames. In this paper, we propose an efficient scheme of passive decoy-state RFI-QKD based on the parametric down-conversion source, where a beam splitter splits the idler pulses into four local detection events to improve the performance of RFI-QKD systems. In addition, we demonstrate the worst relative rotation of reference frames in our scheme. Simulation results show that our scheme can achieve good performance even at the worst-case scenario. Highlights • An efficient scheme of passive decoy-state reference-frame-independent quantum key distribution is presented. • We demonstrate the worst-case scenario of passive decoy-state reference-frame-independent quantum key distribution. • Passive decoy-state reference-frame-independent quantum key distribution can achieve good performance at the worst-case scenario. [ABSTRACT FROM AUTHOR]

The numerous participants in convention and exhibition (C&E) events and the consequently huge consumption of direct and indirect resources have increased the environmental pressure on C&E centers to implement environmentally friendly practices and procedures. This paper explores the innovative methods adopted by green-certified C&E centers and synthesizes a reference framework of environmental mitigation practices for the C&E sector in the Greater Bay Area, which was recently designated as a major regional development area in China. Eleven green-certified C&E centers were selected to establish a comprehensive and indicative framework containing 59 actual environmental practices in three major categories. Suggestions made by 12 experts for modifying the fit of the constructed framework to suit the local geographical and climatic situations of C&E centers in the China Greater Bay Area were examined. [ABSTRACT FROM AUTHOR]

Highlights • We propose a new geometric pairwise constraint to check whether two correspondences are compatible. • We propose a voting-based scheme to rank 3D correspondences. • The proposed method is efficient and robust to a variety of disturbances. Abstract This paper addresses the 3D correspondence ordering problem by proposing a consistency voting (CV) method. Given a set of plausible feature correspondences generated via geometric feature matching, our goal is to rank these correspondences accurately and robustly such that reasonable correspondences can be located according to their rankings. The proposed method employs a voting-based scheme, which is based on the consistency check of each initial correspondence with a predefined voting set, to calculate a voting score for each correspondence. We consider two consistency terms, i.e., rigidity and local reference frame (LRF) affinity, to ensure a correct judge when two correspondences are compatible. LRF is an intrinsic canonical cue widely used in many existing local geometric features. The repeatability of LRFs helps to remove the ambiguity that sometimes arises from the rigidity check. The proposed CV method is evaluated on three public benchmarks including both LiDAR and Kinect data. Comparison with the state-of-the-art confirms the effectiveness and robustness of the CV method with respect to noise, varying point densities, clutter, occlusion, and changes in data modality. Furthermore, the proposed CV method can rank thousands of correspondences in real time. [ABSTRACT FROM AUTHOR]

Different reference frames are used in daily life in order to structure the environment. The two-choice Simon task setting has been used to investigate how task-irrelevant spatial information influences human cognitive control. In recent studies, a Go/NoGo Simon task setting was used in order to divide the Simon task between a pair of participants. Yet, not only a human co-actor, but also even an attention-grabbing object can provide sufficient reference in order to reintroduce a Simon effect (SE) indicating cognitive conflict in Go/NoGo task settings. Interestingly, the SE could only occur when a reference point outside of the stimulus setup was available. The current studies exploited the dependency between different spatial reference frames (egocentric and allocentric) offered by the stimulus setup itself and the task setup (individual vs. joint Go/NoGot task setting). Two studies (Experiments 1 and 2) were carried out along with a human co-actor. Experiment 3 used an attention-grabbing object instead. The egocentric and allocentric SEs triggered by different features of the stimulus setup (global vs. local) were modulated by the task setup. When interacting with a human co-actor, an egocentric SE was found for global features of the stimulus setup (i.e., stimulus position on the screen). In contrast, an allocentric SE was yielded in the individual task setup illustrating the relevance of more local features of the stimulus setup (i.e., the manikin's ball position). Results point toward salience shifts between different spatial reference frames depending on the nature of the task setup. [ABSTRACT FROM AUTHOR]

Abstract In this paper, a moving reference frame-based gas-kinetic BGK (MRF–BGK) scheme is developed for simulation of viscous flows around arbitrarily moving bodies. Different from most of existing gas-kinetic schemes, the BGK model is now constructed in a general moving reference frame. Due to the non-inertial effects, there will be an additional acceleration term in the Boltzmann equation, which should be carefully defined in order to correctly recover the concerned Navier–Stokes (N–S) equations. This recovery actually serves as a basis for developing the present method. Within the finite volume framework, the BGK model with the inclusion of the acceleration term is locally solved and the numerical fluxes at the cell interface can be evaluated. Through this way, the source (acceleration) term effects can be naturally included into the gas evolution process and the resulting fluxes. Considering that explicit BGK schemes may show low efficiency for certain unsteady applications where the physical time scales are significantly larger than the spatial scales, the dual time-stepping approach together with an implicit BGK scheme is employed. Numerical tests show that the developed MRF–BGK scheme can be well applied for several incompressible and compressible viscous flows. The accuracy is shown to be comparable to the moving grid BGK method, however the mesh movement is avoided in the present method. Also as compared with the immersed boundary BGK method, it is more efficient to deal with high-Reynolds number flows. Highlights • A moving reference frame-BGK scheme is developed for flows around moving bodies. • The source effects are considered by adding an acceleration term to the BGK model. • The dual time-stepping for implicit BGK scheme is used for efficient simulation. [ABSTRACT FROM AUTHOR]

Orientation systems found around the North Atlantic Rim - those of Greenland, Iceland and the Faroe Islands - have much in common, although two quite unrelated language families are involved. This has much to do with comparable geographical situations and may be taken as supporting Palmer’s Topographic Correspondence Hypothesis. The actual orientation of north-south-east-west terms can vary around the coasts of Iceland and the Faroes as it does around Greenland. All three regions arguably display ‘absolute’ systems, but most noteworthy is the fact that they apply differently at different spatial scales, ranging from the individual house and its surroundings, via specific stretches of coast, up to the broadest frame covering the whole country. The same terms may be used at all levels, only disambiguated by context. There are of course also differences between the systems of the three regions, reflecting their different cultural and technological backgrounds and the geographical alignment of their convoluted coastlines. The question as to whether such systems represent a distinct ‘landmark’ sub-type of absolute system is addressed. It is argued that distinctions of scale are more relevant here than the distinction between ‘cardinal’ and ‘landmark’ sub-types. [ABSTRACT FROM AUTHOR]

We introduce a class of frames, called USB frames (frames of uniform subframe bounds), which mean that any subsequence of the frame is a frame for the subspace it spans and the frame bounds depend only on the cardinality of the subsequence. We give several necessary and sufficient conditions for a frame to be a USB frame. As an application, we show that a tight USB frame is optimal for erasures in the sense that the reconstruction error is independent of the position of erasures. We give several explicit construction of USB frames. [ABSTRACT FROM AUTHOR]

The article presents an interview with philosopher and musician Michael Krausz who discusses his concept of relativity. He comments on the nature of reference frames in relativism. Topics discussed include his definition of relativism, variables in relativism, and the connection between realism, universalism and foundationalism.

This is a comment on an article by Thomas E. Phipps, Jr., that has appeared in this journal [Phys. Essays 27, 591 (2014)]. He reconfirmed that Maxwell equations are Galilean invariant. The global positioning system (GPS) uses the collective time (GPS clock). Phipps refuted Lorentz length contraction, and noted that covariance has been consistently banished in favor of invariance; furthermore, he concluded that spacetime symmetry is invalidated. Phipps did not accept the existence of an ether. On this point, we do not agree with him and assume the ether as a preferred reference frame. We recommend that Phipps's invariant physics should be studied. [ABSTRACT FROM AUTHOR]

If the speed of light is independent of the movement of its source, then it should make no difference at all when clocks are synchronized using light sources at rest or moving ones. It seems it does. When clocks are synchronized in two reference frames, moving relatively to one another, the causal relations between two particular events will depend on whether sources at rest or moving ones have been used. This inconsistency will appear solid evidence that the speed of light can never be invariant. [ABSTRACT FROM AUTHOR]

Since the introduction of prospect theory, reference-dependence and loss-aversion have become widely acknowledged as important elements affecting decision-making. Nevertheless, establishing and determining reference frames are not extensively analyzed in the literature; rather, in most applications, it is simply assumed that the reference frames can be represented through the status quo . This assumption, however, may lead to biased results, as not only the status quo affects reference frames, but also previous experiences or expectations, among many others. Therefore, it would be more appropriate to estimate the reference frame directly as an unobserved latent variable. Unfortunately, current utility functions utilized to depict this kind of behavior are not useful for this purpose, as they are defined piecewise. This work proposes a smooth twice-differentiable utility function that indeed allows estimating reference frames. Further, this function satisfies all major properties of prospect theory. Finally, the approach is tested relying on three case studies. They show that in the context of semi-compensatory loss-averted decision-making reference frames may diverge from the status quo . [ABSTRACT FROM AUTHOR]

This paper presents a cross-linguistic investigation of a constraint on the use on intrinsic frames of reference proposed by Levelt (1984, 1996). This proposed constraint claims that use of intrinsic frames when the ground object is in non-canonical position is blocked due to conflict with gravitational-based reference frames. Regression models of the data from Arabic, K'iche', Spanish, Yucatec, and Zapotec suggest that this constraint is valid across languages. However, the strength at which the constraint operates is predicted by the frequency of canonical intrinsic frames in the particular language. The ratio of the incidence of intrinsic usage with canonical vs. non-canonical orientation appears to be remarkably uniform across languages, which suggests the possibility of a strong cognitive universal. [ABSTRACT FROM AUTHOR]

This study investigated the impact of criterion-based vs. social reference frames on behavioural and neural correlates of performance monitoring while taking individual differences in control beliefs into account. We conducted two experiments administering a time estimation task in which feedback was either delivered pertaining to participants’ own performance (nonsocial/criterion-based reference) or to the performance of a reference group of previous participants (social reference). In Experiment 1, 34 male volunteers participated. To test generalizability of the observed results to both sexes/genders, we recruited 36 female volunteers for Experiment 2. P2 and P300 amplitudes were generally larger in social than in nonsocial reference trials in the male participants of Experiment 1. ΔFRN amplitudes were larger for social compared to non-social reference trials in Experiment 1. No effects of reference frame were found in the female sample of Experiment 2. Rather, P2 and ΔFRN effects showed opposing patterns for nonsocial versus social reference frames. However, stronger internal control beliefs were accompanied by larger FRN amplitudes of negative social reference trials in both samples, suggesting generalizable effects independent of sex/gender. Enhanced P2 and ΔFRN amplitudes for social versus nonsocial reference trials suggest enhanced attentional capture and higher saliency of socially framed feedback in male participants only. In both sexes/genders, however, the social reference frame possibly challenges internal control beliefs and by this enhances performance monitoring. Our results demonstrate the complex interplay of trait variables and reference frames during performance monitoring influencing our daily lives-reference frames are omnipresent in education and one’s working environment. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Technical development, new applications and requests for increased accuracy in georeferencing are setting new demands for accuracy and reliability of reference frames. Due to crustal deformations and local movements of benchmarks, a static reference network deteriorates with time, thus eventually requiring update of the whole system. Technically, renewal of a reference frame is straightforward and should be done whenever enough new data or updated information exist to get an improvement in accuracy. An example is the International Terrestrial Reference Frame, ITRF, which is renewed regularly. The situation is more complicated with national reference frames which may have been given a legal status, and parameters defined by the national legislation. Even without that, renewal and implementation of such a frame is a multi-million euro project taking years to complete. Crustal deformations and movements deteriorate static reference frames (defined by fixed/static coordinates of benchmarks) with time. Eventually, distortions in a static reference frame will become bigger than the uncertainties of GNSS measurements, thus deteriorating the obtainable accuracy of the measurement technique. Instead of a static reference frame, one can use semi-kinematic or kinematic approach where either the transformation from global to the national reference frame or the coordinates of reference frame benchmarks are time-dependent. In this paper we give a short overview of the topic, and discuss on technical issues and future aspects of the reference frames in the viewpoint of National Mapping and Cadastre Authorities (NMA) with an example on the national strategy in Finland. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

A system of averaged equations of planetary motion around a central star is constructed. An astrocentric coordinate system is used. The two-planet problem is considered, but all constructions are easily generalized to an arbitrary number N of planets. The motion is investigated in modified (complex) Poincarécanonical elements. The averaging is performed by the Hori-Deprit method over the fast mean longitudes to the second order relative to the planetary masses. An expansion of the disturbing function is constructed using the Laplace coefficients. Some terms of the expansion of the disturbing function and the first terms of the expansion of the averaged Hamiltonian are given. The results of this paper can be used to investigate the evolution of orbits with moderate eccentricities and inclinations in various planetary systems. [ABSTRACT FROM AUTHOR]

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

In this work, we consider the propagation speed of the superenergy flux associated to the Einstein-Rosen cylindrical waves propagating in vacuum and over the background of the gravitational field of an infinitely long mass line distribution. The velocity of the flux is determined considering the reference frame in which the super-Poynting vector vanishes. This reference frame is then considered as comoving with the flux. The explicit expressions for the velocities are given with respect to a reference frame at rest with the symmetry axis. [ABSTRACT FROM AUTHOR]

Co-actors need to anticipate each other's actions to successfully perform joint actions. The frames of reference (FOR) used to simulate a co-actor's action could impact what information is anticipated. We hypothesized that co-actor's would adopt their co-actor's body-centered FOR, even when they do not share the same spatial orientation, so that they could anticipate body-related aspects of their co-actor's task. Because it might be beneficial to plan joint actions based on environment and body-centered information, we hypothesized that individuals would utilize multiple FORs during response planning. To test these hypotheses, participants performed a sequential aiming task where the goal was to move a wooden dowel to one of four potential targets as quickly and accurately as possible. A cue was presented at the beginning of each trial that was either 25, 50, or 75% valid. Following the cue presentation, the first person to act (initiator) placed the wooden dowel, anywhere they liked, in the workspace. Then, the finisher performed their aiming movement from the location that the initiator had placed the dowel. The key dependent measure was the dowel placement of the initiator because it provided an index of how much the initiator attempted to facilitate the efficient performance of the finisher. The results revealed that individuals adopted an allocentric FOR (dowel placement was more biased toward cued locations as cue validity increased) and partially adopted their co-actor's body-centered FOR (dowel placement was biased toward the finisher's body, but not toward the co-actor's contralateral space). In conclusion, multiple FORs can be used to anticipate both body- and environment-related information of a co-actor's task. It may be difficult, however, for individuals to fully adopt their co-actor's body-centered FOR when they have differing orientations. [ABSTRACT FROM AUTHOR]

We present a method that aligns lunar south and north pole LOLA DTMs using selected LOLA tracks and co-registration techniques. The selected LOLA tracks were then co-registered to the aligned polar DTMs with the aim to create a new LOLA frame of high relative accuracy. At the poles the relative accuracy of the resulting LOLA frame improved in comparison with the original LOLA frame, especially at the north pole. At lower latitudes on the lunar near side we could show that we achieve smaller residuals between our LOLA frame and a photogrammetrically derived reference DTM than with the original LOLA frame. On the far side we could not achieve better results which we believe is stemming from the generally less accurate orbit knowledge there. From the aligned polar DTMs we were able to derive a polar radius of 1738,049 km. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The present study has two-fold aims: to investigate whether gender differences persist even when more time is given to acquire spatial information; to assess the gender effect when the retrieval phase requires recalling the pathway from the same or a different reference perspective (egocentric or allocentric). Specifically, we analyse the performance of men and women while learning a path from a map or by observing an experimenter in a real environment. We then asked them to reproduce the learned path using the same reference system (map learning vs. map retrieval or real environment learning vs. real environment retrieval) or using a different reference system (map learning vs. real environment retrieval or vice versa). The results showed that gender differences were not present in the retrieval phase when women have the necessary time to acquire spatial information. Moreover, using the egocentric coordinates (both in the learning and retrieval phase) proved easier than the other conditions, whereas learning through allocentric coordinates and then retrieving the environmental information using egocentric coordinates proved to be the most difficult. Results showed that by manipulating familiarity, gender differences disappear, or are attenuated in all conditions. [ABSTRACT FROM AUTHOR]

Primates rely predominantly on vision to gather information from the environment and neurons representing visual space and gaze position are found in many brain areas. Within the medial temporal lobe, a brain region critical for memory, neurons in the entorhinal cortex of macaque monkeys exhibit spatial selectivity for gaze position. Specifically, the firing rate of single neurons reflects fixation location within a visual image (Killian et al., 2012). In the rodents, entorhinal cells such as grid cells, border cells, and head direction cells show spatial representations aligned to visual environmental features instead of the body (Hafting et ah, 2005; Sargolini et ah, 2006; Solstad et ah, 2008; Diehl et ah, 2017). However, it is not known whether similar allocentric representations exist in primate entorhinal cortex. Here, we recorded neural activity in the entorhinal cortex in two male rhesus monkeys during a naturalistic, free-viewing task. Our data reveal that a majority of entorhinal neurons represent gaze position and that simultaneously recorded neurons represent gaze position relative to distinct spatial reference frames, with some neurons aligned to the visual image and others aligned to the monkey's head position. Our results also show that entorhinal neural activity can be used to predict gaze position with a high degree of accuracy. These findings demonstrate that visuospatial representation is a fundamental property of entorhinal neurons in primates and suggest that entorhinal cortex may support relational memory and motor planning by coding attentional locus in distinct, behaviorally relevant frames of reference. [ABSTRACT FROM AUTHOR]

Owing to rapid depletion of fossil fuels and environmental hazard, different non-conventional sources of energy like wind, geothermal, nuclear, photovoltaic etc, have been taken into consideration for power generation. Environmental familiarness, reduced installation cost, improved power quality, abundant availability of source makes photovoltaic based distributed generation as one of the most popular alternative source of energy production. Improvement in power electronics technology makes synchronization of PV system with grid more viable. Power output from the PV module changes continuously with time depending upon the climatic condition. In order to get maximum output from the PV system different types of MPPT algorithm present in literature are studied and improvement proposed are described in this paper. Furthermore, different types of inverter topologies along with different grid synchronization technique and PWM topologies used to connect the PV system with the 3-phase AC grid are presented. In order to minimize the harmonic content of the inverter output, different types of filters used are presented in the proceeding section. Nextly different commonly used advanced islanding detection techniques for the safety purpose of PV based distribution generation system have been addressed and based on advantages and limitation of anti-islanding techniques, a comparison table has been presented. Afterward based on parameters like input, output voltage & current, MPP range, used standards etc, a comparison table between different commercially available grid tied PV inverters are presented in this paper. Finally, drawbacks of the prevailing grid connected PV system have been discussed. [ABSTRACT FROM AUTHOR]

A study found that Dutch-speaking children who prefer an egocentric (left/right) reference frame when describing spatial relationships, and Hai||om-speaking children who use a geocentric (north/south) frame had difficulty recreating small-scale spatial arrays using their language-incongruent system (Haun, Rapold, Janzen, & Levinson, 2011). In five experiments, we reconciled these results with another study showing that English (egocentric) and Tseltal Mayan (geocentric) speakers can flexibly use both systems (Abarbanell, 2010; Li, Abarbanell, Gleitman, & Papafragou, 2011). In replicating and extending Haun et al. (Experiment 1), English- but not Tseltal-speaking children could use their language-incongruent system when the instructions used their non-preferred frame of reference. Perseveration due to task order may explain the discrepancies between present English- and previous Dutch-speaking children, while not understanding task instructions using left/right language may explain why present Tseltal- and previous Hai||om-speaking children had difficulty with their language-incongruent systems. In support, Tseltal-speaking children could use an egocentric system when the instructions were conveyed without left/right language (Experiments 2-4), and many did not know left/right language (Experiment 5). These findings help reconcile seemingly conflicting sets of results and suggest that task constraints, rather than language, determine which system is easier to use (Experiment 2 vs. 3). [ABSTRACT FROM AUTHOR]

For three-phase voltage source converters (VSC), current control in d-q reference frame (RF) and direct power control (DPC) under balanced voltage conditions (BVC) are regulation problems, and current control in the α-β RF (CCAB) is a tracking problem. Conventional sliding mode control-based proportional controllers are sometimes adopted for current and power regulation, proportional plus resonant controllers are often used for CCAB. However, these controllers cannot ensure accurate current and power control due to time delays in the control loops. In this paper, practical SMC-based regulation and tracking controllers for VSC are designed. For current and power regulation, an integral SMC controller of which integral actions are included in both the control law and the sliding manifold is proposed. For CCAB, a current tracking controller, including proportional, resonant and derivative control laws is presented. System stability in Lyapunov sense is guaranteed and convergence of the state errors to zero is strictly proved based on Barbalat' Lemma. Finally, simulation studies on DPC under BVC and on CCAB are conducted to verify the effectiveness and to demonstrate superiority of the proposed controllers. [ABSTRACT FROM AUTHOR]

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) andNAVIC (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 (Medium Earth Orbit) satellites are considered. For all satellites, position differences according to the broadcast ephemeris relative to IGS14/CODE orbits are projected to the radial, along-track and crosstrack triad, with the largest periodic differences affecting mostly the along track component. Sudden discontinuities at the level of up to 1 m and 2-3 ns are observed for the along-track component and the satellite clock, respectively. The time scales of GLONASS, Galileo, QZSS, SBAS and NAVIC are very closely aligned to GPS, with constant offsets depending on receiver type. The offset of the BeiDou time scale to GPS has an oscillatory pattern with peak-to-peak values up to 100 ns. To characterize receiver-dependent biases the average of six Septentrio receivers is taken as reference, and relative offsets of the other receiver types are investigated. These receiver-dependent biases may depend on the individual station, or for the same station on the update of the firmware. A detailed calibration history is presented for each multiGNSS station studied. [ABSTRACT FROM AUTHOR]

We consider a particle falling into a rotating black hole. Such a particle makes an infinite number of revolutions n from the viewpoint of a remote observer who uses the Boyer-Lindquist type of coordinates. We examine the behavior of n when it is measured with respect to a local reference frame that also rotates due to dragging effect of spacetime. The crucial point consists here in the observation that for a nonextremal black hole, the leading contributions to n from a particle itself and the reference frame have the same form being in fact universal, so that divergences mutually cancel. As a result, the relative number of revolutions turns out to be finite. For the extremal black hole this is not so, n can be infinite. Different choices of the local reference frame are considered, the results turn out to be the same qualitatively. For illustration, we discuss two explicit examples-rotation in the flat spacetime and in the Kerr metric. [ABSTRACT FROM AUTHOR]

Spatial Frames of Reference (FoRs) are mental coordinate systems applied to locate a Figure (F) with respect to a Ground (G). In Levinson’s theory (2003), every language selects a dominant FoR among Intrinsic, Relative and Absolute, leaving non-dominant FoRs for restricted sets of cases. Bohnemeyer (2011) enlarged this typology, describing ‘referentially promiscuous systems’, as characterized by free switch among FoRs and absence of a default strategy used by the whole community. We show here that Traditional Negev Arabic (TNA) represents a new, hitherto unknown type, which we label ‘referential complementarity’: all its speakers use all three FoRs in everyday discourse, yet not freely switching among them. Different Gs of traditional life, when observed in their traditional locations, prime specific referential strategies: inherently partitioned Gs (horse/coffee-pot) prime the binary Intrinsic FoR; those with no inherent partition (stone/tree) prime ternary Relative or Absolute FoRs, depending on their alignment vis-à-vis the Observer (O). Interestingly, culturally salient objects considered integral to the tent, such as a hosting cushion or a tent pole, absorb the tent’s Intrinsic orientation; but outside the tent these behave just like their non-tent-integral counterparts (stone/tree). In particular, the Absolute FoR is used for (i) culturally unfamiliar Gs (chair/shoe/dinosaur) and (ii) certain Gs in non-salient O-F-G alignments. We conclude that FoR selection in TNA follows culture-specific rules, paying more attention to cultural familiarity or salience than to supposedly universal metrical and formal features. [ABSTRACT FROM AUTHOR]

The article discusses the concepts of work and inertia frames with the help of a used car.

To help us live in the three-dimensional world, our brain integrates incoming spatial information into reference frames, which are based either on our own body (egocentric) or independent from it (allocentric). Such frames, however, may be crucial not only when interacting with the visual world, but also in language comprehension, since even the simplest utterance can be understood from different perspectives. While significant progress has been made in elucidating how linguistic factors, such as pronouns, influence reference frame adoption, the neural underpinnings of this ability are largely unknown. Building on the neural reuse framework, this study tested the hypothesis that reference frame processing in language comprehension involves mechanisms used in navigation and spatial cognition. We recorded EEG activity in 28 healthy volunteers to identify spatiotemporal dynamics in (1) spatial navigation, and (2) a language comprehension task (sentence-picture matching). By decomposing the EEG signal into a set of maximally independent activity patterns, we localised and identified a subset of components which best characterised perspective-taking in both domains. Remarkably, we find individual co-variability across these tasks: people's strategies in spatial navigation are also reflected in their construction of sentential perspective. Furthermore, a distributed network of cortical generators of such strategy-dependent activity responded not only in navigation, but in sentence comprehension. Thus we report, for the first time, evidence for shared brain mechanisms across these two domains - advancing our understanding of language's interaction with other cognitive systems, and the individual differences shaping comprehension. [ABSTRACT FROM AUTHOR]

A new methodology for computing the gravitational effect of a spherical tesseroid has been devised and implemented. The methodology is based on the rotation from the global Earth-Centred Rotational reference frame to the local Earth-Centred P-Rotational reference frame, referred to the computation point P, and it requires knowledge of the height and the angular extension of each topographic column. After rotation, the gravitational effect of the tesseroid is computed via the effect of a sector of the spherical zonal band. In this respect, two possible procedures for handling the rotated tesseroids have been proposed and tested. The results obtained with the devised methodology are in good agreement with those derived by applying other existing methodologies. [ABSTRACT FROM AUTHOR]