Search results for "Space-time"

40 years of time geography: from the conceptual framework to the GI Science contributions

2011

International audience; Social scientists studying the effects of space on human behavior usually consider the time dimension as an external factor. Activities are analyzed in an aggregate sense such that the process of individual decision-making is depicted as the single case of "the average individual." In order to link efficiently space and time dimensions, Torsten Hägerstrand defined in 1970's the concept of Time Geography and thereby founded the school of Swedish geography. His conceptual framework was destined to change the course of history in the social sciences. After 40 years, this success has transcended scientific boundaries. In this paper, we propose to review the evolution of …

OH_FET: a computer application for analysing urban dynamics over long time spans

2015

International audience; OH_FET formalism has been designed to analyse urban fabric over long time spans (Lefebvre et al., 2008; Rodier and Saligny, 2010; Rodier et al., 2010). The conceptual model is founded on the idea of historical object (OH – objet historique) which is defined as the Cartesian product of three elementary dimensions: social use (what), space (where) and time (when). Processes are performed in Python programming language and data are stored in various kinds of spatial database. With a minimum of required data from archaeologists’ observations, the application allows users to automate the calculation of standardised indicators about urban transformations and to generate gr…

Beyond GDP: an analysis of the socio-economic diversity of European regions

2019

International audience; This paper aims to analyze the socioeconomic diversity of the European Union (EU-28) regions from a dynamic perspective. For that purpose, we combine a series of exploratory space-time analysis approaches to multiple Factor Analysis (MFA) applied to a large range of indicators collected at the NUTS-2 level for the period 2000–2015 for the EU-28. First, we find that the first factor of MFA, interpreted as economic development (ECO-DEV), is spatially clustered and that a moderate convergence process is at work between European regions from 2000 to 2015. Second, when comparing these results with those obtained for Gross Domestic Product (GDP) per capita, we show that th…

A space-time branching process with covariates

2018

The paper proposes a stochastic process that improves the assessment of seismic events in space and time, considering a contagion model (branching process) within a regression-like framework. The proposed approach develops the Forward Likelihood for prediction (FLP) method including covariates in the epidemic component.

The exceptionality of space-time symetries

2009

Modélisation des objets historiques selon la fonction, l'espace et le temps pour l'étude des dynamiques urbaines dans la longue durée

2010

The proposed principle for understanding the urban fabric is based on considering the town as a set of complex objects, taking a systemic approach. The town system used to study the urban fabric over large time spans is composed of three sub-systems relating to historical objects from the level of the excavation to that of the former urban space: function (social use), space (location, surface area and morphology) and time (dating, duration and chronology). The historical object is the analytical unit of the space studied. The purposed model allows urban changes to be observed. The originality of this procedure lies in its approach whereby it is possible to start not from the mapping of a p…

Identification of international media events by spatial and temporal aggregation of RSS flows of newspapers

2013

The GEOMEDIA research project (ANR Corpus, 2013-2015) aims to elaborate an international observatory of media events, based on the collection of RSS flows sent by 100 newspapers of French and English languages. This contribution (1) describes the complexity of the information contained in RSS flows according to space, time and media dimensions; (2) derives basic solutions for the identification of international events on the basis of procedures of time aggregation; (3) analyzes the spatial interaction between countries through an analysis of co-quotations in RSS flows; (4) checks the existence of possible interactions between the two previous dimensions.

Functional Type Error Control for Stabilised Space-Time IgA Approximations to Parabolic Problems

2018

The paper is concerned with reliable space-time IgA schemes for parabolic initial-boundary value problems. We deduce a posteriori error estimates and investigate their applicability to space-time IgA approximations. Since the derivation is based on purely functional arguments, the estimates do not contain mesh dependent constants and are valid for any approximation from the admissible (energy) class. In particular, they imply estimates for discrete norms associated with stabilised space-time IgA approximations. Finally, we illustrate the reliability and efficiency of presented error estimates for the approximate solutions recovered with IgA techniques on a model example. peerReviewed

Spatial representations of future in Homeric Greek

2015

The aim of this paper is to investigate the space-time mapping of the future in Homeric Greek. It is widely accepted that the spatial adverbs πρόσσω ‘in front’ and ὀπίσσω ‘behind’ in the Homeric poems are used to portray temporal events located in a sequence of aligned entities that follow one after the other on the same path (Dunkel, 1983, p. 66). In such a temporal sequence, or Time-rp model, those adverbs are associated respectively to past and future events in a bipartite spatial representation of time, without involving a deictic ego-experiencer. After analyzing data from the Homeric poems in a cognitive linguistic perspective, it is found that some temporal uses of the preposition πρό…

On the effects of suitably designed space microstructures in the propagation of waves in time modulated composites

2023

In the one-dimensional case, the amplitude of a pulse that propagates in a homogeneous material whose properties are instantaneously changed in time will undergo an exponential increase due to the interference between the reflected and transmitted pulses generated at each sudden switch. Here, we resolve the issue by designing suitable reciprocal PT-symmetric space-time microstructures so that the interference between the scattered waves is such that the overall amplitude of the wave will be constant in time in each constituent material. Remarkably, for the geometries proposed here, a pulse will propagate with constant amplitude regardless of the impedance between the constituent materials,…