West Nile Virus: DYCAST spatial-temporal model. Why spatial is special. Modifiable area unit problem (MAUP) Results of statistical analysis are sensitive to the zoning system used to report aggregated data
Jan 1, 1999 to Dec 31, 1999
Jan 1, 2000 to Dec 31, 2000
Jan 1, 2001 to Dec 31, 2001
Jan 1, 2002 to Dec 31, 2002
Jan 1, 2003 to Dec 31, 2003
Jan 1, 2004 to Dec 31, 2004
Jan 1, 2005 to Dec 31, 2005
Jan 1, 2006 to Dec 31, 2006
Jan 1, 2007 to Sept. 25, 2007
Source: The Centers for Disease Control and Prevention;
Photo Source: Ornithology and MammalogyDepartment, Cornell University
Data Source: Komar, N. unpublished. Used with permission
Iowa State University online image gallery
N : the total number of pairs that can be formed from:
n data points
T: the test statistic
tij: the distance between points i and j: 0 if greater than the critical distance, 1 otherwise
sij: the time between points i and j: 0 if greater than the critical time, 1 otherwise
cell o11 is T, close in space and time
cell o21 are the pairs close in space only (not in space and time)
cell o12 are the pairs close in time only (not in space and time)
cell O22 are pairs not close in space nor time
Sweep the cylinder with a smaller cylinder of closeness in search for close pairs.
Randomly seed the cylinder with X number of points.
Count the number of pairs that can be formed from the points that fall in the smaller cylinder of closeness. Also keep track of close-space, close-time pairs.
Repeat 5000 times.
Run for a selected combination of windows and days prior
Figure 1 Illustration of temporal windows and days prior to onset and model prediction: most likely time maximum viremia exist in environment
Figure 2. Time: mosquito infection to onset date of human infection.
Deriving Cellular Automata Rules for Areas at Risk of West Nile Virus Infection24-Bit Encoding Schemes (Master Templates)
G. Green, PhD student, CARSI, Hunter College – City University of New York; S. Ahearn, CARSI, Hunter College – CUNY;R. Carney, California Department of Health Services; and A. McConchie, CARSI, Hunter College - CUNY
ArcEngine Model with Daily Sacramento Area DYCAST Output Raster
Selection of master template and sub-templates via mutual information and genetic algorithm based on accuracy of CA output:
2005 Sacramento Season
Sacramento CA Accuracy
Data: California Department of Health Services