We show how to actively compute qualitative shape properties directly from image intensities that is, without having to rst \reconstruct the surface". Our approach diverges from classical active shape from shading [1] in two important ways. First, we do not attempt to compute a dense depth map of the surface. We rather detect the presence of certain qualitative geometric features. Second, we us...

Dynamical systems with multiple time scales arise naturally in many domains. Models of neural systems provide the principal motivation for this paper. Most of the previous mathematical analysis of qualitative properties of multiple time scale systems has dealt with local phenomena that occur in low dimensions. The neural system models raise questions that lie beyond the scope of existing work. ...

In this paper we develop an overlapping generation model to study the life cycle choices of heterogeneous households and characterize the dynamics of metropolitan communities. The model focuses on household sorting and local public good provision in a system of local jurisdictions. We define equilibrium and characterize its qualitative properties. We develop an algorithm to compute equilibria a...

Lin proposed earlier based on qualitative considerations that electronic motion was associated with negative absolute temperature. Here, a local temperature formula is proposed for electronic motion in atoms and molecules, which allows the existence of negative absolute temperature in a local sense in thermodynamic equilibrium. The proposed temperature formula is a function of total energy dens...

In periodically varying environments, population models generate periodic dynamical systems. To understand the effects of unidirectional dispersal on local patch dynamics in fluctuating environments, dynamical systems theory is used to study the resulting periodic dynamical systems. In particular, a unidirectional dispersal linked two patch nonautonomous metapopulation model is constructed and ...

This paper describes peculiar qualitative effects occurring in texture appearance, resulting from the manipulation of the amount of textural microelements. Keeping fixed the textural local properties, the increase of microelements’ number produces a texture aspect more homogeneous and denser. Conversely, patterns filled by a small number of elements exhibit a more salient subparts’ articulation...

This paper contains a review of the characterization and recovery of motion from image sequences. The main dichotomy of considered approaches is in terms of the extent of the region of description, namely, local (infinitesimal) versus regional. The local consideration concentrates on the recovery of optical flow, while the regional considerations provide richer, potentially semantically meaning...

Qualitative simulation is a key inference process in qualitative causal reasoning, In this paper, we present the QSIM algorithm, a new algorithm for qualitative simulation that generalizes the best features of rxisting algorithms, and allows direct comparisons among alternate approaches. QSIM is an efficient constraint-satisfaction algorithm that can follow either its standard semantics allowin...

OBJECTIVE Our study provides information on phenotypes of local chickens and guinea fowl and their body measures as well as on major genes in local chickens in northern Ghana. METHODS Qualitative and morphometric traits were recorded on 788 local chickens and 394 guinea fowl in urban households in Tamale, Ghana. RESULTS The results showed considerable variation of color traits and numerous ...