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Journal articles on the topic 'Space and time (Representations)'

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Published: 4 June 2021

Last updated: 20 February 2023

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1

Carlson, Thomas A., J. Brendan Ritchie, Nikolaus Kriegeskorte, Samir Durvasula, and Junsheng Ma. "Reaction Time for Object Categorization Is Predicted by Representational Distance." Journal of Cognitive Neuroscience 26, no. 1 (January 2014): 132–42. http://dx.doi.org/10.1162/jocn_a_00476.

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How does the brain translate an internal representation of an object into a decision about the object's category? Recent studies have uncovered the structure of object representations in inferior temporal cortex (IT) using multivariate pattern analysis methods. These studies have shown that representations of individual object exemplars in IT occupy distinct locations in a high-dimensional activation space, with object exemplar representations clustering into distinguishable regions based on category (e.g., animate vs. inanimate objects). In this study, we hypothesized that a representational boundary between category representations in this activation space also constitutes a decision boundary for categorization. We show that behavioral RTs for categorizing objects are well described by our activation space hypothesis. Interpreted in terms of classical and contemporary models of decision-making, our results suggest that the process of settling on an internal representation of a stimulus is itself partially constitutive of decision-making for object categorization.

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2

van Wassenhove, Virginie. "Minding time in an amodal representational space." Philosophical Transactions of the Royal Society B: Biological Sciences 364, no. 1525 (July 12, 2009): 1815–30. http://dx.doi.org/10.1098/rstb.2009.0023.

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How long did it take you to read this sentence? Chances are your response is a ball park estimate and its value depends on how fast you have scanned the text, how prepared you have been for this question, perhaps your mood or how much attention you have paid to these words. Time perception is here addressed in three sections. The first section summarizes theoretical difficulties in time perception research, specifically those pertaining to the representation of time and temporal processing. The second section reviews non-exhaustively temporal effects in multisensory perception. Sensory modalities interact in temporal judgement tasks, suggesting that (i) at some level of sensory analysis, the temporal properties across senses can be integrated in building a time percept and (ii) the representational format across senses is compatible for establishing such a percept. In the last section, a two-step analysis of temporal properties is sketched out. In the first step, it is proposed that temporal properties are automatically encoded at early stages of sensory analysis, thus providing the raw material for the building of a time percept; in the second step, time representations become available to perception through attentional gating of the raw temporal representations and via re-encoding into abstract representations.

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3

Greatbatch, Ian. "Representations of Time and Space." Information Visualization 3, no. 1 (March 2004): 60–61. http://dx.doi.org/10.1057/palgrave.ivs.9500064.

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4

McGranaghan, Matt. "Representations of Space and Time." Cartographic Perspectives, no. 46 (September 1, 2003): 66–70. http://dx.doi.org/10.14714/cp46.487.

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5

Batsakis, Sotiris, Ilias Tachmazidis, and Grigoris Antoniou. "Representing Time and Space for the Semantic Web." International Journal on Artificial Intelligence Tools 26, no. 03 (June 2017): 1750015. http://dx.doi.org/10.1142/s0218213017600156.

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Representation of temporal and spatial information for the Semantic Web often involves qualitative defined information (i.e., information described using natural language terms such as “before” or “overlaps”) since precise dates or coordinates are not always available. This work proposes several temporal representations for time points and intervals and spatial topological representations in ontologies by means of OWL properties and reasoning rules in SWRL. All representations are fully compliant with existing Semantic Web standards and W3C recommendations. Although qualitative representations for temporal interval and point relations and spatial topological relations exist, this is the first work proposing representations combining qualitative and quantitative information for the Semantic Web. In addition to this, several existing and proposed approaches are compared using different reasoners and experimental results are presented in detail. The proposed approach is applied to topological relations (RCC5 and RCC8) supporting both qualitative and quantitative (i.e., using coordinates) spatial relations. Experimental results illustrate that reasoning performance differs greatly between different representations and reasoners. To the best of our knowledge, this is the first such experimental evaluation of both qualitative and quantitative Semantic Web temporal and spatial representations. In addition to the above, querying performance using SPARQL is evaluated. Evaluation results demonstrate that extracting qualitative relations from quantitative representations using reasoning rules and querying qualitative relations instead of directly querying quantitative representations increases performance at query time.

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6

Jaramillo, J. L., and V. Aldaya. "Space-time dynamics from algebra representations." Journal of Physics A: Mathematical and General 32, no. 47 (November 11, 1999): L503—L507. http://dx.doi.org/10.1088/0305-4470/32/47/102.

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7

Beudel, M., R. Renken, K. L. Leenders, and B. M. de Jong. "Cerebral representations of space and time." NeuroImage 44, no. 3 (February 2009): 1032–40. http://dx.doi.org/10.1016/j.neuroimage.2008.09.028.

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8

Kober, Martin. "Canonical quantum gravity on noncommutative space–time." International Journal of Modern Physics A 30, no. 17 (June 20, 2015): 1550085. http://dx.doi.org/10.1142/s0217751x15500852.

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In this paper canonical quantum gravity on noncommutative space–time is considered. The corresponding generalized classical theory is formulated by using the Moyal star product, which enables the representation of the field quantities depending on noncommuting coordinates by generalized quantities depending on usual coordinates. But not only the classical theory has to be generalized in analogy to other field theories. Besides, the necessity arises to replace the commutator between the gravitational field operator and its canonical conjugated quantity by a corresponding generalized expression on noncommutative space–time. Accordingly the transition to the quantum theory has also to be performed in a generalized way and leads to extended representations of the quantum theoretical operators. If the generalized representations of the operators are inserted to the generalized constraints, one obtains the corresponding generalized quantum constraints including the Hamiltonian constraint as dynamical constraint. After considering quantum geometrodynamics under incorporation of a coupling to matter fields, the theory is transferred to the Ashtekar formalism. The holonomy representation of the gravitational field as it is used in loop quantum gravity opens the possibility to calculate the corresponding generalized area operator.

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9

Silva-Coira, Fernando, José R. Paramá, Guillermo de Bernardo, and Diego Seco. "Space-efficient representations of raster time series." Information Sciences 566 (August 2021): 300–325. http://dx.doi.org/10.1016/j.ins.2021.03.035.

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10

Zhao, Haipeng, and Joseph Bentsman. "Biorthogonal Wavelet Based Identification of Fast Linear Time-Varying Systems—Part I: System Representations12." Journal of Dynamic Systems, Measurement, and Control 123, no. 4 (December 27, 2000): 585–92. http://dx.doi.org/10.1115/1.1409549.

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An analytical framework is developed that permits the input-output representations of discrete-time linear time-varying (LTV) systems in terms of biorthogonal bases on compact time intervals. Using these representations, the companion paper, Part II develops computational procedures for rapid identification of fast nonsmooth LTV systems based on short data records. One of the representations proposed is also used in H. Zhao and J. Bentsman, “Block Diagram Reduction of the Interconnected Linear Time-Varying Systems in the Time Frequency Domain,” accepted for publication by Multidimensional Systems and Signal Processing to form system interconnections, or wavelet networks, and develop subsystem connectibility conditions and reduction rules. Under the assumption that the inputs and the outputs of the plants considered in the present work belong to lp spaces, where p=2 or p=∞, their impulse responses are shown to belong to Banach spaces. Further on, by demonstrating that the set of all bounded-input bounded-output (BIBO) stable discrete-time LTV systems is a Banach space, the system representation problem is shown to be reducible to the linear approximation problem in the Banach space setting, with the approximation errors converging to zero as the number of terms in the representation increases. Three types of LTV system representation, based on the input-side, the output-side, and the input-output transformations, are developed and the suitability of each representation for matching a particular type of the LTV system behavior is indicated.

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11

Vrotsou, Katerina, Camilla Forsell, and Matthew Cooper. "2D and 3D Representations for Feature Recognition in Time Geographical Diary Data." Information Visualization 9, no. 4 (December 3, 2009): 263–76. http://dx.doi.org/10.1057/ivs.2009.30.

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Time geographical representations are becoming a common approach to analysing spatio-temporal data. Such representations appear intuitive in the process of identifying patterns and features as paths of populations form tracks through the 3D space, which can be seen converging and diverging over time. In this article, we compare 2D and 3D representations within a time geographical visual analysis tool for activity diary data. We identify a representative task and evaluate task performance between the two representations. The results show that the 3D representation has benefits over the 2D representation for feature identification but also indicate that these benefits can be lost if the 3D representation is not carefully constructed to help the user to see them.

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12

Bazhlekova, Emilia, and Ivan Bazhlekov. "Subordination Approach to Space-Time Fractional Diffusion." Mathematics 7, no. 5 (May 9, 2019): 415. http://dx.doi.org/10.3390/math7050415.

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The fundamental solution to the multi-dimensional space-time fractional diffusion equation is studied by applying the subordination principle, which provides a relation to the classical Gaussian function. Integral representations in terms of Mittag-Leffler functions are derived for the fundamental solution and the subordination kernel. The obtained integral representations are used for numerical evaluation of the fundamental solution for different values of the parameters.

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13

Loeffler, Jonna, Markus Raab, and Rouwen Cañal-Bruland. "Does movement influence representations of time and space?" PLOS ONE 12, no. 4 (April 4, 2017): e0175192. http://dx.doi.org/10.1371/journal.pone.0175192.

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14

Kleinschmidt, A., and P. West. "Representations of and the role of space-time." Journal of High Energy Physics 2004, no. 02 (February 12, 2004): 033. http://dx.doi.org/10.1088/1126-6708/2004/02/033.

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15

de Hevia, Maria Dolores, Véronique Izard, Aurélie Coubart, Elizabeth S. Spelke, and Arlette Streri. "Representations of space, time, and number in neonates." Proceedings of the National Academy of Sciences 111, no. 13 (March 17, 2014): 4809–13. http://dx.doi.org/10.1073/pnas.1323628111.

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16

Hendricks, Rose K., and Lera Boroditsky. "New Space-Time Metaphors Foster New Nonlinguistic Representations." Topics in Cognitive Science 9, no. 3 (June 21, 2017): 800–818. http://dx.doi.org/10.1111/tops.12279.

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17

Royer, Antoine. "Galilean space-time symmetries in Liouville space and Wigner-Weyl representations." Physical Review A 45, no. 2 (January 1, 1992): 793–810. http://dx.doi.org/10.1103/physreva.45.793.

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18

Deuar, Piotr. "Multi-time correlations in the positive-P, Q, and doubled phase-space representations." Quantum 5 (May 10, 2021): 455. http://dx.doi.org/10.22331/q-2021-05-10-455.

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A number of physically intuitive results for the calculation of multi-time correlations in phase-space representations of quantum mechanics are obtained. They relate time-dependent stochastic samples to multi-time observables, and rely on the presence of derivative-free operator identities. In particular, expressions for time-ordered normal-ordered observables in the positive-P distribution are derived which replace Heisenberg operators with the bare time-dependent stochastic variables, confirming extension of earlier such results for the Glauber-Sudarshan P. Analogous expressions are found for the anti-normal-ordered case of the doubled phase-space Q representation, along with conversion rules among doubled phase-space s-ordered representations. The latter are then shown to be readily exploited to further calculate anti-normal and mixed-ordered multi-time observables in the positive-P, Wigner, and doubled-Wigner representations. Which mixed-order observables are amenable and which are not is indicated, and explicit tallies are given up to 4th order. Overall, the theory of quantum multi-time observables in phase-space representations is extended, allowing non-perturbative treatment of many cases. The accuracy, usability, and scalability of the results to large systems is demonstrated using stochastic simulations of the unconventional photon blockade system and a related Bose-Hubbard chain. In addition, a robust but simple algorithm for integration of stochastic equations for phase-space samples is provided.

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19

de Orellana, Pablo. "Retrieving how diplomacy writes subjects, space and time: a methodological contribution." European Journal of International Relations 26, no. 2 (August 22, 2019): 469–94. http://dx.doi.org/10.1177/1354066119868514.

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How does diplomacy describe international actors? Diplomatic practices observe, analyse, prioritise and constitute information that is ultimately committed to text. Drawing on post-structuralist approaches to identity, diplomacy and textuality, this paper argues for consideration of the unique role of diplomatic text in constituting the state and especially its representation and understanding of Self and Other. It consequently develops a methodology to empirically analyse how the text of diplomatic communication describes people, places, time, politics, and informs policy. The analytical method proposed adjusts and expands post-structuralist discourse analysis, adapting it to the intertextual study of large collections of diplomatic knowledge production documents. It firstly determines data selection in relation to diplomacy’s own theory. Secondly, it develops an approach to retrieve how any diplomatic text constitutes representations of subjects and their contexts. Thirdly, it follows the development of representations across diplomatic knowledge production, identifying when they come to influence other international actors. This approach is demonstrated in the analysis of America’s 1945–1948 diplomatic road to involvement in Vietnam, showing how diplomacy’s representation of actors were vital to US involvement, and identifying hitherto unconsidered events, descriptions and actors. These analytics contribute to and empirically substantiate understanding of how diplomacy constitutes Self and Other, informs policy and shapes world politics.

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20

Brunec, Iva K. "Unified and Separable Hippocampal Representations of Time and Space." Journal of Neuroscience 36, no. 49 (December 7, 2016): 12293–95. http://dx.doi.org/10.1523/jneurosci.2860-16.2016.

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21

Johnson, Dudley Paul. "Hilbert space representations of general discrete time stochastic processes." Stochastic Processes and their Applications 19, no. 1 (February 1985): 183–87. http://dx.doi.org/10.1016/0304-4149(85)90049-3.

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22

Johnson, Dudley Paul. "Hilbert space representations of general discrete time stochastic processes." Stochastic Processes and their Applications 43, no. 2 (December 1992): 363–65. http://dx.doi.org/10.1016/0304-4149(92)90069-3.

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23

Aoki, Masanao. "On alternative state space representations of time series models." Journal of Economic Dynamics and Control 12, no. 2-3 (June 1988): 595–607. http://dx.doi.org/10.1016/0165-1889(88)90058-9.

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24

McElree, Brian, and Barbara Anne Dosher. "The focus of attention across space and across time." Behavioral and Brain Sciences 24, no. 1 (February 2001): 129–30. http://dx.doi.org/10.1017/s0140525x01373922.

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Measures of retrieval speed for recently presented events show a sharp dichotomy between representations in focal attention and representations that are recently processed but no longer attended. When information is presented over time, retrieval measures show that focal attention and rapid privileged access is limited to the most recently processed unit or chunk, not the last 3–5 chunks that Cowan estimates from various recall procedures.

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25

Embrechts, Paul, Erwan Koch, and Christian Robert. "Space‒time max-stable models with spectral separability." Advances in Applied Probability 48, A (July 2016): 77–97. http://dx.doi.org/10.1017/apr.2016.43.

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AbstractNatural disasters may have considerable impact on society as well as on the (re-)insurance industry. Max-stable processes are ideally suited for the modelling of the spatial extent of such extreme events, but it is often assumed that there is no temporal dependence. Only a few papers have introduced spatiotemporal max-stable models, extending the Smith, Schlather and Brown‒Resnick spatial processes. These models suffer from two major drawbacks: time plays a similar role to space and the temporal dynamics are not explicit. In order to overcome these defects, we introduce spatiotemporal max-stable models where we partly decouple the influence of time and space in their spectral representations. We introduce both continuous- and discrete-time versions. We then consider particular Markovian cases with a max-autoregressive representation and discuss their properties. Finally, we briefly propose an inference methodology which is tested through a simulation study.

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26

Zhang, Meng, and Yi Zhang. "Space-Efficient Representations for Glushkov Automata." International Journal of Foundations of Computer Science 29, no. 07 (November 2018): 1089–105. http://dx.doi.org/10.1142/s0129054118500223.

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Glushkov automaton is an efficient structure for matching regular expressions. We present an [Formula: see text] bits space representation of Glushkov automata of regular expressions, where [Formula: see text] is the number of strings in the regular expression. The state transition runs in time [Formula: see text], where [Formula: see text] is the size of machine words, and [Formula: see text] is the number of states in the Glushkov automaton. For [Formula: see text], the time is [Formula: see text]. Our approach is based on two operations on words that retrieve and set bits on a specific set of positions of a word. We present implementations of these operations using bit-parallelism and a permutation network, which are simple and efficient.

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27

Luiz Silveira da Silva, Leonardo. "INTERMEDIANDO REPRESENTAÇÕES ÀS MARGENS DOS ESTEREÓTIPOS DO TEMPO E ESPAÇO." REVISTA GEONORTE 13, no. 41 (June 30, 2022): 1–19. http://dx.doi.org/10.21170/geonorte.2022.v.13.n.41.01.19.

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The article in question defends, throughan epistemological discussion, that the discursive intermediation is an interesting path to mitigate the incompleteness of the representations. It starts from the assumption that mind and matter are part of an inseparable interweaving, which justifies theimportance of reflection regarding representations. The starting point for understanding the incompleteness of representations is the consideration that they suppress a significant amount of temporal and spatial experience, reproducing images that are strengthened in the relationships of affection. It is also noteworthy that the intellectual often falls into a kind of paradoxical trap: in the act of deconstructing stereotypes within a given theme, there is a tendency to generalize and to elaborate typologies that stereotype the imaginative plurality. It is these discursive problems that the article seeks to address

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28

Cotaescu, Ion I. "Canonical quantization of the covariant fields on de Sitter space–times." International Journal of Modern Physics A 33, no. 08 (March 20, 2018): 1830007. http://dx.doi.org/10.1142/s0217751x18300077.

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The properties of the covariant quantum fields on de Sitter space–times are investigated focusing on the isometry generators and Casimir operators in order to establish the equivalence among the covariant representations and the unitary irreducible ones of the de Sitter isometry group. For the Dirac quantum field, it is shown that the spinor covariant representation, transforming the Dirac field under de Sitter isometries, is equivalent with a direct sum of two unitary irreducible representations of the [Formula: see text] group, transforming alike the particle and antiparticle field operators in momentum representation. Their basis generators and Casimir operators are written down finding that the covariant representations are equivalent with unitary irreducible ones from the principal series whose canonical weights are determined by the fermion mass and spin.

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29

Vilela Mendes, R. "Space–times over normed division algebras, revisited." International Journal of Modern Physics A 35, no. 10 (April 10, 2020): 2050055. http://dx.doi.org/10.1142/s0217751x20500554.

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Normed division and Clifford algebras have been extensively used in the past as a mathematical framework to accommodate the structures of the Standard Model and grand unified theories. Less discussed has been the question of why such algebraic structures appear in Nature. One possibility could be an intrinsic complex, quaternionic or octonionic nature of the space–time manifold. Then, an obvious question is why space–time appears nevertheless to be simply parametrized by the real numbers. How the real slices of an higher-dimensional space–time manifold might be almost independent from each other is discussed here. This comes about as a result of the different nature of the representations of the real kinematical groups and those of the extended spaces. Some of the internal symmetry transformations might however appear as representations on homogeneous spaces of the extended group transformations that cannot be implemented on the elementary states.

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30

Arzano, Michele. "The Unruh effect without space–time." International Journal of Geometric Methods in Modern Physics 17, no. 04 (March 2020): 2050057. http://dx.doi.org/10.1142/s0219887820500577.

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We show how the characteristic thermal effects found for a quantum field in space–time geometries admitting a causal horizon can be found in a simple quantum system living on the real line. The analysis we present is essentially group theoretic in nature: a thermal state emerges naturally when comparing representations of the group of affine transformations of the real line. The freedom in the choice of different notions of translation generators is the key to the one-dimensional Unruh effect we describe.

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31

Dan, Jingpei, Weiren Shi, Fangyan Dong, and Kaoru Hirota. "Piecewise Trend Approximation: A Ratio-Based Time Series Representation." Abstract and Applied Analysis 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/603629.

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A time series representation, piecewise trend approximation (PTA), is proposed to improve efficiency of time series data mining in high dimensional large databases. PTA represents time series in concise form while retaining main trends in original time series; the dimensionality of original data is therefore reduced, and the key features are maintained. Different from the representations that based on original data space, PTA transforms original data space into the feature space of ratio between any two consecutive data points in original time series, of which sign and magnitude indicate changing direction and degree of local trend, respectively. Based on the ratio-based feature space, segmentation is performed such that each two conjoint segments have different trends, and then the piecewise segments are approximated by the ratios between the first and last points within the segments. To validate the proposed PTA, it is compared with classical time series representations PAA and APCA on two classical datasets by applying the commonly used K-NN classification algorithm. For ControlChart dataset, PTA outperforms them by 3.55% and 2.33% higher classification accuracy and 8.94% and 7.07% higher for Mixed-BagShapes dataset, respectively. It is indicated that the proposed PTA is effective for high dimensional time series data mining.

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32

Sun, Li, Zhongbao Zhang, Jiawei Zhang, Feiyang Wang, Hao Peng, Sen Su, and Philip S. Yu. "Hyperbolic Variational Graph Neural Network for Modeling Dynamic Graphs." Proceedings of the AAAI Conference on Artificial Intelligence 35, no. 5 (May 18, 2021): 4375–83. http://dx.doi.org/10.1609/aaai.v35i5.16563.

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Learning representations for graphs plays a critical role in a wide spectrum of downstream applications. In this paper, we summarize the limitations of the prior works in three folds: representation space, modeling dynamics and modeling uncertainty. To bridge this gap, we propose to learn dynamic graph representations in hyperbolic space, for the first time, which aims to infer stochastic node representations. Working with hyperbolic space, we present a novel Hyperbolic Variational Graph Neural Network, referred to as HVGNN. In particular, to model the dynamics, we introduce a Temporal GNN (TGNN) based on a theoretically grounded time encoding approach. To model the uncertainty, we devise a hyperbolic graph variational autoencoder built upon the proposed TGNN to generate stochastic node representations of hyperbolic normal distributions. Furthermore, we introduce a reparameterisable sampling algorithm for the hyperbolic normal distribution to enable the gradient-based learning of HVGNN. Extensive experiments show that HVGNN outperforms state-of-the-art baselines on real-world datasets.

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33

Ohya, Satoshi. "Intertwining operator in thermal CFTd." International Journal of Modern Physics A 32, no. 02n03 (January 25, 2017): 1750006. http://dx.doi.org/10.1142/s0217751x17500063.

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It has long been known that two-point functions of conformal field theory (CFT) are nothing but the integral kernels of intertwining operators for two equivalent representations of conformal algebra. Such intertwining operators are known to fulfill some operator identities — the intertwining relations — in the representation space of conformal algebra. Meanwhile, it has been known that the S-matrix operator in scattering theory is nothing but the intertwining operator between the Hilbert spaces of in- and out-particles. Inspired by this algebraic resemblance, in this paper, we develop a simple Lie-algebraic approach to momentum-space two-point functions of thermal CFT living on the hyperbolic space–time [Formula: see text] by exploiting the idea of Kerimov’s intertwining operator approach to exact S-matrix. We show that in thermal CFT on [Formula: see text], the intertwining relations reduce to certain linear recurrence relations for two-point functions in the complex momentum space. By solving these recurrence relations, we obtain the momentum-space representations of advanced and retarded two-point functions as well as positive- and negative-frequency two-point Wightman functions for a scalar primary operator in arbitrary space–time dimension [Formula: see text].

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34

Srivastava, Garima, Rashmi Gupta, Raghvendra Kumar, and Dac-Nhuong Le. "Space-Time Code Design Using Quaternions, Octonions and Other Non-Associative Structures." International journal of electrical and computer engineering systems 10, no. 2 (January 15, 2020): 91–95. http://dx.doi.org/10.32985/ijeces.10.2.5.

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There are several non-associative finite dimensional division algebras over different number fields. Their representations in the corresponding matrix algebras preserve additive structure. However, the embedding does not preserve multiplication as matrix multiplication is associative. As such, it gives a generalized matrix representation. Indeed, a non-associative structure provides different platforms for more effective and useful space-time coding satisfying rank criteria, and coding gain criteria for multiple antenna wireless communication. Associative division algebras have dimension restrictions, whereas non-associative division algebras over suitable fields exist in infinitely many dimensions. We illustrate the above program by using octonion algebras.

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35

Balashova, Elenа Yu, and Ekaterina M. Dubovskaya. "Representations of real and virtual space and time: age aspect." New Psychological Research 1, no. 4 (2021): 25–46. http://dx.doi.org/10.51217/npsyresearch_2021_01_04_02.

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36

Martinsen, Andreas B., and Anastasios M. Lekkas. "Two Space-Time Obstacle Representations Based on Ellipsoids and Polytopes." IEEE Access 9 (2021): 111152–61. http://dx.doi.org/10.1109/access.2021.3103323.

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37

Olivers, C., and D. Schreij. "Object representations maintain attentional control settings across space and time." Journal of Vision 11, no. 11 (September 23, 2011): 141. http://dx.doi.org/10.1167/11.11.141.

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38

Pearson, R. K., and Ü. Kotta. "Nonlinear discrete-time models: state-space vs. I/O representations." Journal of Process Control 14, no. 5 (August 2004): 533–38. http://dx.doi.org/10.1016/j.jprocont.2003.09.007.

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39

Fuchs, Erich, Thiemo Gruber, Helmuth Pree, and Bernhard Sick. "Temporal data mining using shape space representations of time series." Neurocomputing 74, no. 1-3 (December 2010): 379–93. http://dx.doi.org/10.1016/j.neucom.2010.03.022.

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40

Burch, Aidan. "Phase space representations and perturbation theory for continuous-time histories." Journal of Mathematical Physics 48, no. 7 (July 2007): 072106. http://dx.doi.org/10.1063/1.2752009.

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41

Schreij, Daniel, and Christian N. L. Olivers. "Object representations maintain attentional control settings across space and time." Cognition 113, no. 1 (October 2009): 111–16. http://dx.doi.org/10.1016/j.cognition.2009.06.016.

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42

Moro, Valentina, Michela Corbella, Silvio Ionta, Federico Ferrari, and Michele Scandola. "Cognitive Training Improves Disconnected Limbs’ Mental Representation and Peripersonal Space after Spinal Cord Injury." International Journal of Environmental Research and Public Health 18, no. 18 (September 12, 2021): 9589. http://dx.doi.org/10.3390/ijerph18189589.

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Paraplegia following spinal cord injury (SCI) affects the mental representation and peripersonal space of the paralysed body parts (i.e., lower limbs). Physical rehabilitation programs can improve these aspects, but the benefits are mostly partial and short-lasting. These limits could be due to the absence of trainings focused on SCI-induced cognitive deficits combined with traditional physical rehabilitation. To test this hypothesis, we assessed in 15 SCI-individuals the effects of adding cognitive recovery protocols (motor imagery–MI) to standard physical rehabilitation programs (Motor + MI training) on mental body representations and space representations, with respect to physical rehabilitation alone (control training). Each training comprised at least eight sessions administered over two weeks. The status of participants’ mental body representation and peripersonal space was assessed at three time points: before the training (T0), after the training (T1), and in a follow-up assessment one month later (T2). The Motor + MI training induced short-term recovery of peripersonal space that however did not persist at T2. Body representation showed a slower neuroplastic recovery at T2, without differences between Motor and the Motor + MI. These results show that body and space representations are plastic after lesions, and open new rehabilitation perspectives.

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Bansal, Suguman, Yong Li, Lucas Tabajara, and Moshe Vardi. "Hybrid Compositional Reasoning for Reactive Synthesis from Finite-Horizon Specifications." Proceedings of the AAAI Conference on Artificial Intelligence 34, no. 06 (April 3, 2020): 9766–74. http://dx.doi.org/10.1609/aaai.v34i06.6528.

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LTLf synthesis is the automated construction of a reactive system from a high-level description, expressed in LTLf, of its finite-horizon behavior. So far, the conversion of LTLf formulas to deterministic finite-state automata (DFAs) has been identified as the primary bottleneck to the scalabity of synthesis. Recent investigations have also shown that the size of the DFA state space plays a critical role in synthesis as well.Therefore, effective resolution of the bottleneck for synthesis requires the conversion to be time and memory performant, and prevent state-space explosion. Current conversion approaches, however, which are based either on explicit-state representation or symbolic-state representation, fail to address these necessities adequately at scale: Explicit-state approaches generate minimal DFA but are slow due to expensive DFA minimization. Symbolic-state representations can be succinct, but due to the lack of DFA minimization they generate such large state spaces that even their symbolic representations cannot compensate for the blow-up.This work proposes a hybrid representation approach for the conversion. Our approach utilizes both explicit and symbolic representations of the state-space, and effectively leverages their complementary strengths. In doing so, we offer an LTLf to DFA conversion technique that addresses all three necessities, hence resolving the bottleneck. A comprehensive empirical evaluation on conversion and synthesis benchmarks supports the merits of our hybrid approach.

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Roche, Andrew F. "Kant’s Transcendental Deduction and the Unity of Space and Time." Kantian Review 23, no. 1 (February 23, 2018): 41–64. http://dx.doi.org/10.1017/s1369415417000371.

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AbstractOn one reading of Kant’s account of our original representations of space and time, they are, in part, products of the understanding or imagination. On another, they are brute, sensible givens, entirely independent of the understanding. In this article, while I agree with the latter interpretation, I argue for a version of it that does more justice to the insights of the former than others currently available. I claim that Kant’s Transcendental Deduction turns on the representations of space and time as determinate, enduring particulars, whose unity is both given and a product of synthesis.

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Bachman, Philip, and Doina Precup. "Learning Compact Representations of Time-Varying Processes." Proceedings of the AAAI Conference on Artificial Intelligence 25, no. 1 (August 4, 2011): 1748–49. http://dx.doi.org/10.1609/aaai.v25i1.8061.

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We seek informative representations of the processes underlying time series data. As a first step, we address problems in which these processes can be approximated by linear models that vary smoothly over time. To facilitate estimation of these linear models, we introduce a method of dimension reduction which significantly reduces error when models are estimated locally for each point in time. This improvement is gained by performing dimension reduction implicitly through the model parameters rather than directly in the observation space.

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Yang, Zihan, Jianqiang Yang, and Kai Ren. "The Analysis of the Spatial Production Mechanism and the Coupling Coordination Degree of the Danwei Compound Based on the Spatial Ternary Dialectics." Processes 9, no. 12 (December 20, 2021): 2281. http://dx.doi.org/10.3390/pr9122281.

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With the gradual deepening of the development of high-quality urban transformation, the “Danwei Compound” urban space production method constitutes the basis of Chinese current urban spatial transformation. The transformation plan of the original danwei compound “stock” to promote the healthy development of urban society has become the focus of research. First, with the help of Lefebvre’s space production theory, combined with the spatial transformation characteristics of its own structural form experienced by the Chinese urban danwei compound, the space production is divided into three stages, namely, the diversity-orderly type average space of the danwei compound system period, dispersed type abstract space of the commercial enclosed community period, and the integrated differential space of a livable community undergoing regeneration and transformation. At each stage, the government, market, and residents have different influences on time-space production. Secondly, using Hefei’s typical danwei compound as the research carrier, according to the space ternary dialectics, a multi-level analysis of “representations of space-representational space-spatial practice” is carried out on the production mechanism, and the logic of different types of spaces in different periods are described. Among them, the representations of space of the change of the danwei compound are the interrelationship of multiple governance subjects in different periods, such as changes in the implementation degree of governance strategies, the degree of residents’ community governance participation, residents’ satisfaction with community governance, etc. The representational space is the residents’ community perception and interpersonal relationship at different transition stages, Interpersonal trust, and other social relations’ changes. Spatial practice is manifested in changes in the support of public service facilities, public space, per capita living area, building quality, architectural style, and illegal building area. Finally, the three-dimensional space dialectical coupling coordination degree model is used to analyze and compare the representations of space of typical settlements in the three stages and the coupling characteristics of the representational space and the practice of space. On this basis, we provide innovative ideas and put forward relevant measures and suggestions for the regeneration, transformation, and development of livable areas.

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Pucciarelli, Marta, and Sara Vannini. "Douala as a “hybrid space”: Comparing online and offline representations of a sub-Saharan city." Semiotica 2018, no. 223 (July 26, 2018): 219–50. http://dx.doi.org/10.1515/sem-2017-0017.

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Abstract This study investigates the complex relationship between the physical and digital spaces of the city of Douala, Cameroon by comparing its online representation with the social representations emerging orally by locals. Using the results of two existing studies reporting on the online image of the city, we investigate the social representations foreigners and locally relevant people have of Douala and uncover similarities and discrepancies of the two resulting representations. Outcomes from the analysis permit reflection on the implications of these and show an unripe, intermediate stage of the “hybrid Douala,” where the virtual space seems still not to be affecting the way the physical space is experienced, as well as where the gaps in the digital divide are perpetuated. At the same time, strong local ownership of certain digital activities suggests how the online image of the city is in the process of being constructed and developed locally. As the spaces of the city start appearing online, the process of hybridization between physical and digital Douala is slowly taking place and offline and online narratives, now rather separated, will possibly communicate a different image of the city to global online narratives.

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BECK, J. CHRISTOPHER, TOM CARCHRAE, EUGENE C. FREUDER, and GEORG RINGWELSKI. "A SPACE-EFFICIENT BACKTRACK-FREE REPRESENTATION FOR CONSTRAINT SATISFACTION PROBLEMS." International Journal on Artificial Intelligence Tools 17, no. 04 (August 2008): 703–30. http://dx.doi.org/10.1142/s0218213008004114.

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In this paper we present a radical approach to obtaining a backtrack-free representation for a constraint satisfaction problem: remove values that lead to dead-ends. This technique does not require additional space but has the drawback of removing solutions. We investigate a number of variations on the basic algorithm including the use of seed solutions, consistency techniques, and a variety of pruning heuristics. Our experimental results indicate that a significant proportion of the solutions to the original problem can be retained especially when an optimization algorithm that specifically searches for such “good” backtrack-free representations is employed. Further extensions increase solution retention by searching for high-coverage backtrack-free representations, by removing tuples rather than values, and by combining multiple backtrack-free representations. Our approach elucidates, for the first time, a three-way trade-off between space complexity, potential backtracks, and solution loss and enables algorithms that can actively reason about the trade-off between space, backtracks, and solution loss.

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SCOLARICI, GIUSEPPE. "SPACE–TIME DISCRETE ℚ-SYMMETRIES IMPLEMENTED AS INTERNAL SYMMETRIES." International Journal of Geometric Methods in Modern Physics 03, no. 03 (May 2006): 631–40. http://dx.doi.org/10.1142/s0219887806001302.

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We classify the irreducible quaternionic representations of the extensions of internal symmetry groups by the group of space–time discrete symmetries. We obtain the possible forms of time reversal violating Hamiltonians in the case that the generalized parity operator is of geometrical type.

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Chauhan, Bhupendra C. S., Pawan Kumar Joshi, and O. P. S. Negi. "Quaternion generalization of super-Poincaré group." International Journal of Modern Physics A 34, no. 01 (January 10, 2019): 1950006. http://dx.doi.org/10.1142/s0217751x19500064.

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Super-Poincaré algebra in [Formula: see text] space–time dimensions has been studied in terms of quaternionic representation of Lorentz group. Starting the connection of quaternion Lorentz group with [Formula: see text] group, the [Formula: see text] spinors for Dirac and Weyl representations of Poincaré group are described consistently to extend the Poincaré algebra to super-Poincaré algebra for [Formula: see text] space–time.

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