Displaying results 1 - 7 of 7
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Dual Graph Spatial Cluster Detection for Syndromic Surveillance in Networks
Content Type: Abstract
Early warning systems must not always rely on geographical proximity for modeling the spread of contagious diseases. Instead, graph structures such as airways or social networks are more adequate in those situations. Nodes,… read more… difficulties for the direct usage of scan statistics, due to the highly irregular structures involved. Besides, … the appearance of an emerging cluster of syndromes due to a real outbreak (signal) amidst unrelated syndromes … the appearance of an emerging cluster of syndromes due to a real out- break (signal) amidst unrelated syndromes … -
Spatial cluster detection through constrained dynamic programming
Content Type: Abstract
The spatial scan statistic [1] is the most used measure for cluster strenght. The evaluation of all possible subsets of regions in a large dataset is computationally infeasible. Many heuristics have appeared recently to compute approximate values… read more… most used measure for cluster strenght. The evaluation of all possible subsets of regions in a large dataset is … and Ricardo H. C. Takahashi2 1Universidade Federal de Ouro Preto, Ouro Preto, MG, Brazil; 2Universidade Federal … most used measure for cluster strenght. The evaluation of all possible subsets of regions in a large dataset is … -
Delineating Spatial Clusters with Artificial Neural Networks
Content Type: Abstract
Multiple or irregularly shaped spatial clusters are often found in disease or syndromic surveillance maps. We develop a novel method to delineate the contours of spatial clusters, especially when there is not a clearly dominating primary cluster,… read more… Ricardo H.C. Takahashi, Luiz Duczmal Universidade Federal de Minas Gerais, Brazil OBJECTIVE Multiple or irregularly … more irregularly shaped clusters, indicating less bias, due to the larger variance allowed. CONCLUSIONS The … A Spatial Scan Statistic, Comm. Statist. Theory Meth., 26(6), 1481-1496. [2] M. H. Fun and M.T. Hagan, 1996. … -
Exploring Multi-Cluster Structures with the Multi-Objective Circular Scan
Content Type: Abstract
The spatial scan statistic is the usual measure of strength of a cluster [1]. Another important measure is its geometric regularity [2]. A genetic multiobjective algorithm was developed elsewhere to identify irregularly shaped clusters [3]. A search… read more… The solution presented is a Pareto-set, consisting of all the clusters found which are not simultaneously worse in … A significance evaluation is conducted in parallel for all clusters in the Pareto-set through Monte Carlo … The solution presented is a Pareto-set, consisting of all the clusters found which are not simultaneously worse in … -
Geographically Meaningful Cluster Scanning Through Weak Link Correction
Content Type: Abstract
Many heuristics were developed recently to find arbitrarily shaped clusters (see review [1]). The most popular statistic is the spatial scan [2]. Nevertheless, even if all cluster solutions could be known, the problem of… read more… statistic is the spatial scan [2]. Nevertheless, even if all cluster solutions could be known, the problem … solution presented is a Pareto-set, consisting of all the clusters found which are not simultaneously worse in … The significance evaluation is conducted in parallel for all the clusters in the Pareto-set through a … -
A new interpretation of the inference test for the spatial scan statistic
Content Type: Abstract
Spatial cluster analysis is considered an important technique for the elucidation of disease causes and epidemiological surveillance. Kulldorff's spatial scan statistic, defined as a likelihood ratio, is the usual measure of the strength of… read more… work, this adjustment is not done in an even manner for all possible cluster sizes. We propose a modification to the … and Ricardo H. Caldeira Takahashi4 1Universidade Federal de São João del Rei, Ouro Branco, Brazil; 2Statistics, … work, this adjustment is not done in an even manner for all possible cluster sizes (3). Methods We pose a modified … -
What Is the True Shape of a Disease Cluster? The Multi-Objective Genetic Scan
Content Type: Abstract
Irregularly shaped spatial disease clusters occur commonly in epidemiological studies, but their geographic delineation is poorly defined. Most current spatial scan software usually displays only one of the many possible cluster solutions with… read more… F. Cançado , Ricardo H. C. Takahashi Universidade Federal de Minas Gerais, Brazil OBJECTIVE We propose a novel … most ir- regularly shaped one, corresponding to varying de- grees of penalization parameters imposed to the free- … scan statistic value (LLR). The Pareto set consists of all clusters candidates z such that no other cluster has …