We fully develop the concept of causal symmetry introduced in [19]. A causal symmetry is a transformation of a Lorentzian manifold (V, g) which maps every future-directed vector onto a future-directed vector. We prove that the set of all causal symmetries is not a group under the usual composition operation but a submonoid of the diffeomorphism group of V . Therefore, the infinitesimal generati...

This paper provides statistical methods that permit the association of socioeconomic status and health to be partially unraveled in panel data by excluding some postulated causal paths, or delimiting their range of action. These methods are applied to the Asset and Health Dynamics of the Oldest Old (AHEAD) Panel to test for the absence of causal links from socioeconomic status (SES) to health i...

Counterfactual analysis has a long and distinguished history in comparative research. To some, counterfactual analysis is central to comparative inquiry because such research typically embraces only a handful of empirical cases (Fearon 1991). If there are only a few instances (e.g., of revolution), then researchers, of necessity, must compare empirical cases to hypothetical cases. The affinity ...

This paper presents correct algorithms for answering the following two questions; (i) Does there exist a causal explanation con­ sistent with a set of background knowledge which explains all of the observed indepen­ dence facts in a sample? (ii) Given that there is such a causal explanation what are the causal relationships common to every such

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In this paper, we present Q U A L E X , a system and algor i thm for generating first-order quali tat ive causal graphs for tutor ia l purposes based on de Kleer and Brown's qualitative modeling theory. Q U A L E X is embedded in a constructive simulation environment called Heart Works which teaches hydraulics principles about the cardio-vascular system to first year college biology students.

This paper introduces a new dynamical model which enhances the relationship between face movements and speech acoustics. Based on the autocorrelation of the acoustics and of the face movements, a causal and a non-causal filter are proposed to approximate dynamical features in the speech signals. The database consisted of sentences recorded acoustically, and by using a Qualisys system to capture...