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Elements of Computational Epidemiology a cellular automata framework for computational epidemiology. fishy.com.br. www.epischisto.org. Computational Epidemiology in the world. http://compepi.cs.uiowa.edu/ http://cerl.unt.edu/ http://healthmap.org/ceg/ http://www.ceal.psu.edu/
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Elements of Computational Epidemiology a cellular automata framework for computational epidemiology fishy.com.br www.epischisto.org
Computational Epidemiology in the world • http://compepi.cs.uiowa.edu/ • http://cerl.unt.edu/ • http://healthmap.org/ceg/ • http://www.ceal.psu.edu/ • http://www.isi.it/research/computational-epidemiology-laboratory • http://www.epischisto.org
we need 3 steps to understand and colaborate with ANKOS in EpiSchisto...
Self-Reproducing Automata History... Cellular Spaces • John von Neumann, 40´s, but... [Ulam, Stanislaw 1952] [von Neumann, John, 1968] [Zuse, Konrad, 1970] [Burks, Arthur (ed.) Essays on Cellular Automata, Univ. Ill, 1970] [Holland, John, 1966] Calculating Spaces
A famous and simple one: Game of Life • Take a look at this applet • http://www.bitstorm.org/gameoflife/ • MATHEMATICAL GAMESThe fantastic combinations of John Conway's new solitaire game "life" • Scientific American, 223 (October 1970): 120-123.
Let´s take some time with this applet to best understand a cellular automaton • http://www.bitstorm.org/gameoflife/
some patterns... • A cell should be black whenever one or two, but not both, of its neighbors were black on the step before.
Are these systems artificial ones?ANew Kind of Science! or ?
natural biotic types Patterns of some seashells, like the ones in Conus and Cymbiola genus, are generated by natural CA. http://www.answers.com/topic/cellular-automaton
MUSIC? Let´s take a bit of time with this site • http://tones.wolfram.com/
The Crucial Experiment – Stephen Wolfram, 1986 22.000 BC Arts Biology Psicology Physics Computing Mathematics Arqueology ... and Epidemiology?
challenges… • Designing tools for investigate local disease clusters through simulation • What’s New? • Utilizing GIS and EPI information for modeling • Combining different simulation paradigms • Designing a tool kit to establish a computational epidemiology model Is it possible?
results... endemic area!??
2ndLet´s define (formally and briefly) to answer in the correct form...
Definition of a Cellular Automaton Cellular automaton A is a set of four objectsA = <G, Z, N, f>, where • G– set of cells • Z– set of possible cells states • N – set, which describes cells neighborhood • f– transition function, rules of the automaton: • Z|N|+1Z (for automaton, which has cells “with memory”) • Z|N|Z (for automaton, which has “memoryless” cells)
ΥC i ,j, C k ,l represents an interaction coefficient that controls all possible interactions between a cell Ci,j and its global neighborhood Gi,j. A function of inter-cell distance and cell population density. Cellular automata - generic models for complex systems Definition of a Fuzzy Set Neighborhood of cell Ci,j is global SCA Gi,j := {(Ck,l,ΥC i ,j, C k ,l) |for all Ck,l Є C, 0 ≤ Υ Ci,j, Ck,l≤1} C is a set of all cells in the CA.
Two-DimensionalGrids Cells that have a common edge with the involved are named as “main neighbors” of the cell (are showed with hatching) The set of actual neighbors of the cell a, which can be found according to N, is denoted as N(a)
Definition of the Rings Formally, if R(a, i) is a set of cells of i-th ring of cell a, then if N describes cells neighborhood as the set of its nearest neighbors, following formula will take place
Rings for Grid of … Different rings are showed with hatching or color
Definition of the Metrics Distance function D(a, b) for retrieving remoteness between cells a and b can be denoted as follows It is proved that this function satisfies to all metrics properties The notion of ring may be generalized for multi-dimensional grids and the distance function, given by last formula, will remain the same
Disease Parameters Vaccination Population Demographics Interaction factors Visualization Data Sets cellular automata and epidemiology Distances
modelling... world cells rules
steps... • Cell Definition • World Definition • Simulating parameters • Transition Rules • Results? • Expansion of Diseases – endemic and epidemic aspects • Barriers
Let´s return to the GAME of LIFE • http://www.bitstorm.org/gameoflife/
Cell Definition • Each cell defines a familiar group • Parameters (states): • Carrying capacity; • Total population; • Susceptible subpopulation; • Infective population; • Recovered subpopulation.
Simulating (cont.) • Neighbourhood radius; • Motion probability; • Immigration probability; • Birth rate; • Death rate; • Virus morbidity; • Vectored infection probability; • Contact infection probability; • Spontaneous infection probability; • Recovery probability; • Re-susceptible probability.
A case study… Schistosomiasis Carne de Vaca – GO Ponta do Canoé!
2006 – 2007, data collect in-loco http://200.17.137.109:8081/xiscanoe/infra-estrutura/expedicoes
2008 – 2009, data analysis and reports...Parasitological exams on 1100 residents Spatial pattern, water use and risk levels associated with the transmission of schistosomiasis on the north coast of Pernambuco, Brazil. Cad. Saúde Pública vol.26 no.5 Rio de Janeiro May 2010. http://dx.doi.org/10.1590/S0102-311X2010000500023
2008 and 2009 data analysis and reports...Summary data for molluscscollected... Ecological aspects and malacological survey to identification of transmission risk' sites for schistosomiasis in Pernambuco North Coast, Brazil. Iheringia, Sér. Zool. 2010, vol.100, n.1, pp. 19-24. http://dx.doi.org/10.1590/S0073-47212010000100003
2009-2010, modellingwith15 real parameters (?) From one year (population 1 snapshot, molluscs 12 snapshots) without previous historical...
a cellular automaton • Cellular automaton A is a set of four objectsA = <G, Z, N, f>, where • G– set of cells • Z– set of possible cells states • N – set, which describes cells neighborhood • f– transition function, rules of the automaton: • Z|N|+1Z (for automaton, which has cells “with memory”) • Z|N|Z (for automaton, which has “memoryless” cells) Moore Neighbourhood (in grey) of the cell marked with a dot in a 2D square grid