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Spatial Phenomena (spatial + phenomenon)

Distribution by Scientific Domains
Humanities and Social Sciences50%

Selected Abstracts

Granularity in Relational Formalisms,With Application to Time and Space Representation

COMPUTATIONAL INTELLIGENCE, Issue 4 2001
Jérôme Euzenat
Temporal and spatial phenomena can be seen at a more or less precise granularity, depending on the kind of perceivable details. As a consequence, the relationship between two objects may differ depending on the granularity considered. When merging representations of different granularity, this may raise problems. This paper presents general rules of granularity conversion in relation algebras. Granularity is considered independently of the specific relation algebra, by investigating operators for converting a representation from one granularity to another and presenting six constraints that they must satisfy. The constraints are shown to be independent and consistent and general results about the existence of such operators are provided. The constraints are used to generate the unique pairs of operators for converting qualitative temporal relationships (upward and downward) from one granularity to another. Then two fundamental constructors (product and weakening) are presented: they permit the generation of new qualitative systems (e.g. space algebra) from existing ones. They are shown to preserve most of the properties of granularity conversion operators. [source]

Local Indicators of Network-Constrained Clusters in Spatial Point Patterns

GEOGRAPHICAL ANALYSIS, Issue 3 2007
Ikuho Yamada
The detection of clustering in a spatial phenomenon of interest is an important issue in spatial pattern analysis. While traditional methods mostly rely on the planar space assumption, many spatial phenomena defy the logic of this assumption. For instance, certain spatial phenomena related to human activities are inherently constrained by a transportation network because of our strong dependence on the transportation system. This article thus introduces an exploratory spatial data analysis method named local indicators of network-constrained clusters (LINCS), for detecting local-scale clustering in a spatial phenomenon that is constrained by a network space. The LINCS method presented here applies to a set of point events distributed over the network space. It is based on the network K -function, which is designed to determine whether an event distribution has a significant clustering tendency with respect to the network space. First, an incremental K -function is developed so as to identify cluster size more explicitly than the original K -function does. Second, to enable identification of cluster locations, a local K -function is derived by decomposing and modifying the original network K -function. The local K -function LINCS, which is referred to as KLINCS, is tested on the distribution of 1997 highway vehicle crashes in the Buffalo, NY area. Also discussed is an adjustment of the KLINCS method for the nonuniformity of the population at risk over the network. As traffic volume can be seen as a surrogate of the population exposed to a risk of vehicle crashes, the spatial distribution of vehicle crashes is examined in relation to that of traffic volumes on the network. The results of the KLINCS analysis are validated through a comparison with priority investigation locations (PILs) designated by the New York State Department of Transportation. [source]

Cross-disciplinary demands of multihost pathogens

JOURNAL OF ANIMAL ECOLOGY, Issue 6 2008
DANIEL T. HAYDON
The dynamics of infectious disease spread depend on host population contact structure. Heterogeneities in this contact structure can arise from various forms of demographic and spatial phenomena. Craft et al. (this issue) have constructed an exploratory simulation model of the spread of canine distemper virus through a multispecies carnivore community. Each species in this community is modelled with a contact structure reflecting host social organization, ranging behaviour, and likely interspecific contact patterns. The results are used to infer the possible roles of different species in determining the observed spatio-temporal incidence of canine distemper virus in Serengeti lions during an outbreak in 1993,94. [source]

Using Space: Agency and Identity in a Public,Housing Development

CITY & COMMUNITY, Issue 3 2002
Kevin Fox Gotham
Recent critiques of conventional poverty research have highlighted the need to move beyond the conceptual limitations of "neighborhood effects" models and the use of the tropes of "adaptation" or "resistance" to explain the behaviors and actions of the urban poor. We use ethnographic field observations and interviews with public,housing residents to address these limitations in the poverty literature, assess competing explanations of poor people's agency, and provide insight into the importance of space as a mediating link between macrostructural constraints and locally situated behaviors. We theorize agency and identity as spatial phenomena,with spatial attributes and spatial influences,and examine how different spatial meanings and locations enable or constrain particular forms of social action and behavior. Our ethnographic and interview data depict several strategies by which residents "use space" to provide a measure of security and protection, to designate and avoid areas of criminality and drug activity, and to challenge or support the redevelopment of public housing. From these data we show that urban space is not a residual phenomenon in which social action occurs, but a constitutive dimension of social life that shapes life experiences, social conflict, and action. [source]