 
 
CAPTION: Above are four frames of a movie showing a side-by-side
comparison of a baseline case (on the left) with a targeted vaccination
and quarantine strategy, in which symptomatic people are interviewed,
most of their recent contacts identified, and the contacts and their
households are vaccinated and sent to quarantine.
The full movie below shows 6 frames per day at 4 hour intervals for
70 days. The bars represent number infected at each location, and
the color represents the fraction of infected people who are infectious.
The attack is presumed to be covert, so until people become symptomatic
around day 10 they continue with their normal activities. (And there
is no difference between the two movies until the ring response is
implemented.) The attack site, a university, is readily visible as
a very large spike in the downtown area which grows and decays every
day as students gather on campus and disperse throughout the city.
Above the views of a sample generic city are strip charts displaying the cumulative
number of people infected and dead as a function of time, and for
the ring response, the number vaccinated and quarantined, which are
important for determining feasibility of the response. These are
not labelled, but the color coding corresponds to the labelled text
below the charts.
Note that the scale on the leftmost chart is a factor of a hundred
different from the rightmost.
smallpox propagation Movie (250 MB!)
Download
here ---250 MB avi file
2) Degree dynamics according to activity
types
 
 
 
 
CAPTION: Each location in EpiSims is associated with several activities.
We consider the primary activity for each location (namely the activity
done by the majority of people visiting that location) and observe
the number of people with this activity at the location (i.e.,/ temporal
degree/), as time progresses.
The figures above show the temporal degrees of a few locations with
different activity types. Each plot shows the temporal degree of
5 randomly chosen locations. The X-axis shows time over a 24 hour
period with 0 being approximately 11.00 p.m. The primary activity
is indicated in the figure. The Y-axis represents the number of individuals
at that location as the day progresses.
The temporal degrees are according to our expectations. For example,
the a) figure, shows 5 different randomly chosen location blocks
labeled homes: the degree decreases considerable during mid-day when
people leave for work then it goes back up when they start returning
home (some people do not return home working night shifts and leading
to a small difference compared to the early morning hours). The locations
where the primary activity is work, fill up with people during mid-day,
to get emptied again by night when they leave, see the b) figure
. The little dips around noon correspond to people leaving workplaces
for lunch. Similarly, for schools, figure e) and colleges figure
f) there is a mid-day fill up, with the difference that in colleges
the evening classes create a second peak.v All these data are result
of the people mobility generated by the TRANSIMs simulation engine,
and thus they are not inputs to the simulation. The fact that these
curves follow our expectations, is a validation of the simulation.
3) Demographics and mixing of the
EpiSims population
CAPTION: Age distribution of the population
 
 
 
 
 
 
 
CAPTION: Demographics are likely to play a very important role in
determining the efficacy of any strategies for disease control. We
study different properties like distribution of age, and contact
patterns for different demographic groups.
Figures a) - o) show the average number of contacts that a particular
age group has with the rest of the population. Each graph corresponds
to a specific age group (say A). The x-axis corresponds to all the
age groups. For a particular age group (say B) on the x-axis, the
(corresponding) value of the y-axis corresponds to the average number
of contacts group A make with group B. The particular age (A) for
which results are plotted is stated above the plot. The empirical
observations agree quite well with our intuition. It also shows the
degree of mixing among parts of population with that belong to various
age groups.
From the pictures a) - g) it follows that youngsters typically have
meetings with youngsters (syblings, schools, etc.). Figures i) -
o) show that adults spend most contact with other adults (work places).
The very high peaks in i), f) and g) show that teenagers have most
contacts among other teenagers of the same age (16-18), and have
little mixing with others.
One reason for studying these distributions is to see if it is possible
to design targeted vaccination strategies that are derived from the
demographic attributes of a population. Mixing properties among various
age-groups help specialize the targeting methodology.
4) small portions of the social network
 
 
CAPTION: These figures display different representations of a same
small part of the person-person contact graph, rendered using a graph
drawing program. Vertices represent individual people, and edges
are present if the two people came into contact for at least an hour
during the day. Vertices are colored by their shortest path distance
in the graph from one of a few individuals. Edges are colored corresponding
to the color of vertices at either end.
Tulip-software.org
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