Space-time Context Research Articles

Cargo cult science, armchair empiricism and the idea of violent conflict

In this paper I develop a philosophical and methodological critique of ‘rationalist’—or ‘social scientific’—approaches to the study of civil war and violent conflict, especially the work of Paul Collier and David Laitin. Rationalist scholars purport to develop universal explanations for the outbreak and the protracted duration of violent conflict using econometric techniques and rational choice reasoning. My critique of their ‘scientific method’ can be summarised in two propositions: first, the scientific approach is considered to be a ‘cargo cult’ science—the cult being universal law-like causalities underpinning social phenomena. Second, most empirical research in this tradition is based on doubtful statistics enriched with anecdotal evidence rather than by empirical field work. Hence, rationalist scholars largely conduct an ‘armchair empiricism’ instead of immersing themselves in the complex nature of social mechanisms in a specific space-time context. I briefly sketch out an alternative approach based on critical realism and how such a research programme could work in practice for studying the political economy of violent conflicts.

ENVIRONMENTAL AESTHETICS AND THE DYNAMIC OBJECT

In this paper, I lay out a case for why those objects of aesthetic attention which are principally characterized as natural objects should be understood not statically, as existing in merely a three-dimensional fixed state, but as dynamic, as existing in a space-time context, complete with change, movement, and flux. After this, I explain why this is important, how the dynamic nature of natural objects raises a concern for aesthetically evaluating natural objects, and how that concern may be addressed.

Spatio-temporal GIS Design for Exploring Interactions of Human Activities

An effective representation of human activities in geographic information systems (GIS) presents a challenging research topic. Recent developments of information and communication technologies (ICT), which enable a virtual space and allow people to interact with others remotely, make such efforts even more difficult. This paper first extends the space–time path concept of Hägerstrand's time geography to represent both physical and virtual activities in a space–time context. A spatio-temporal GIS design which can accommodate the extended space–time path concept is proposed to support the exploration of spatio-temporal patterns of human interactions in physical and virtual spaces. Using time as a linear referencing system, a temporal dynamic segmentation method was developed to dynamically locate physical and virtual activities on space–time paths. The GIS design supports the identification of four different spatio-temporal patterns (i.e., co-existence, co-location in space, co-location in time, and no co-location in either space or time) of human interactions through their space–time paths. Using a hypothetical activity dataset, a prototype system is implemented as a three-dimensional GIS (i.e., two-dimensional space + one-dimensional time) in ArcGIS. The prototype system demonstrates the feasibility and potential of applying spatio-temporal GIS concepts to extend Hagerstrand's time–geographic framework for the representation and analysis of human interactions in both physical and virtual spaces. The proposed GIS design can be useful in such applications as understanding traffic congestion, tracking terrorist activities, and modeling the spread of infectious diseases.

Re-evaluating the impact of urban form on travel patternsin Europe and North-America

The work by Newman, Kenworthy and colleagues on the link between land use, transportation systems and travel patterns and energy use has been received enthusiastically but also criticised strongly. In this paper concerns are expressed about the role accorded to individual travellers and the wider space-time context of cities in the empirical-analytical work by Kenworthy and colleagues. To investigate the seriousness of these concerns, the data collected by Kenworthy and colleagues for European, Canadian and US cities in 1990 have been augmented with information on housing, urban development history and the sociodemographic situation. Regression models are described in which the role of urban form is investigated while account is taken of other relevant factors. The empirical analysis suggests that the space-time context of cities should be taken into account in aggregate-level comparisons of the relations between urban form and transport. Policy recommendations based on the original data may be reconsidered and tailored to the space-time context and population characteristics of cities.

Spacetime Ehlers group: transformation law for the Weyl tensor

The spacetime Ehlers group, which is a symmetry of the Einstein vacuumfield equations for strictly stationary spacetimes, is defined and analysedin a purely spacetime context (without invoking the projectionformalism). In this setting, the Ehlers group finds its natural descriptionwithin an infinite-dimensional group of transformations that mapsLorentz metrics into Lorentz metrics and which may be of independentinterest. The Ehlers group is shown to be well defined independently of thecausal character of the Killing vector (which may become null on arbitraryregions). We analyse which global conditions are required on thespacetime for the existence of the Ehlers group. The transformation lawfor the Weyl tensor under Ehlers transformations is obtainedexplicitly.This allows us to study where, and under what circumstances, curvaturesingularities in the transformed spacetime will arise. The results of thepaper are applied to obtain a local characterization of the Kerr-NUTmetric.

A teaching approach to time-geography: Some results of an educational experiment

The conceptual structure of time-geography allows for the study of interactions between general processes and activities that reverberate in the daily life of an individual. Studying daily life at a local level and in its specific spacetime context could thus serve as a laboratory setting for a new approach to teaching geography. This implies using elements that combine to offer a perspective on didactic techniques. Let us introduce these elements in consecutive order.

Hierarchical tendencies amongst world cities: a global research proposal

This is a plea for global-scale analyses of social change with particular reference to the study of the hypothesis that there is a world city hierarchy. Data deficiencies (state-centrism and attribute bias) and theoretical limitations in conceptualizing how a world city hierarchy might develop are highlighted and suggestions for overcoming these problems are presented. Empirically, this involves a pilot study of US world cities using geographical content analysis of the business section of city newspapers to explore inter-city relations. Theoretically, it is proposed that the static conception of hierarchy be replaced by the more modest idea of hierarchical tendencies within a broader space-time context. Combining these empirical and theoretical proposals, a research programme for a global study is outlined and readers are invited to consider how it might be implemented.

Comparison of kriging techniques in a space-time context

Space-time processes constitute a particular class, requiring suitable tools in order to predict values in time and space, such as a space-time variogram or covariance function. The space-time covariance function is defined and linked to the Linear Model of Coregionalization under second-order space-time stationarity. Simple and ordinary space-time kriging systems are compared to simple and ordinary cokriging and their differences for unbiasedness conditions are underlined. The ordinary space-time kriging estimation then is applied to simulated data. Prediction variances and prediction errors are compared with those for ordinary kriging and cokriging under different unbiasedness conditions using a cross validation. The results show that space-time kriging tend to produce lower prediction variances and prediction errors that kriging and cokriging.

A SUM of science: The taxonomy and methodology of sociophysics

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