The
spread of disease has always plagued mankind. Great epidemics have
ended millions of lives in the past, making the study of such diseases
all the more important. But new problems also plague us as we grow and
expand in the world. Overpopulation in many regions of the world has led
to transportation challenges and complicated the optimal siting of
facilities or the delivery of services such as hospitals and police.
Then there are smaller problems in the world, such as how useful the new
bike-sharing system in Charlotte actually is. All of these seem so
unrelated, but Dr. Eric Delmelle
sees the connection: geography. And, using engineering techniques, he
and his team plan to help solve all of these problems, one by one.
When
it comes to epidemiology, Delmelle's interests are in the modeling of
vector-based diseases, specifically dengue fever, which is spread by
mosquitos: "These diseases have a particular spatial and temporal
signature” ," Delmelle noted. "These diseases create geographical
patterns and clusters in specific areas, which is critical for
prevention purposes" says Delmelle. All of this mass of data comes from
the Health Ministry of Columbia, specifically for the city of Cali. "It
is a large, dynamicmetropolitan area that has seen a lot of migrants
moving in with poor sanitation infrastructure, which makes it a
particularly interesting environment," he noted.
Figure 1 displays dengue fever cases in 2010, which was considered an outbreak in dengue fever. Spatial and space-time smoothing techniques are used to extract meaningful patterns of dengue intensity.
Figure 1 displays dengue fever cases in 2010, which was considered an outbreak in dengue fever. Spatial and space-time smoothing techniques are used to extract meaningful patterns of dengue intensity.
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| Dengue fever cases in the city of Cali, Colombia (a), spatial patterns in (b) and space-time patterns in (c). |
The
purpose of this research is to better understand the spatial patterns
of infectious disease and predict where they will reemerge. Though we
may not see dengue fever as a critical problem in the United States,
other infectious diseases are at alarming levels, such as West Nile
Virus. With a changing climate, the risk of similar diseases only goes
up, especially in the southern states, such as Florida. Along those
lines, Delmelle also collaborates with Dr. Eastin, an associate
professor of meteorology in the Geography and Earth Sciences Department
in order to help predict dengue fever outbreaks in the city of Cali. For
instance, weather forecasts may help predict accurate counts of dengue
fever, helping to increase awareness among population of an imminent
risk. Using an autoregressive model, the team predicted a significantly
high number of dengue cases in 2013. By mid-February 2013, the city of
Cali had reported 1339 cases, with three individuals dying of the disease.
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| Another Diagram Explaining the Space-Time patterns of the dengue fever |
This
research stream is not just for research sake. Delmelle and his team
take all of their findings back to the individuals they have worked with
in Columbia. "We have the chance to visit numerous times on-site,
receive critical feedback from local authorities on the techniques we
use and to validate our results." Establishing a connection with local
decision makers is a very important part of the process to Delmelle. "We
do not tell people what they should do, but we do inform them on the
risks posed by infectious diseases. It's important to see that the
results of our models can be beneficial to the local communities for
prevention purposes. ”
Vector
born illnesses are not the only research problem Delmelle is interested
in. Using similar spatial modeling techniques, Delmelle also tackles
general problems in urban areas."Several problems we study are of
geographic nature" Delmelle tells me. By utilizing engineering
techniques –such as operations research -, Delmelle and his team look to
optimize particular problems. In the case of infectious diseases, the
optimal space-time allocation of spraying efforts may help reduce the
magnitude of the infection.
Yet,
the same techniques can be used for other, more basic problems. Delmelle brings his
research approaches to look at local issues, helping the
Charlotte-Mecklenburg region with multiple dilemmas. One such major issue
is the question of where to site schools in a city that is only growing in population,
but not evenly across the county. By attacking the problem as a
quantitative optimization problem -- a number problem -- Delmelle and his
team are able to utilize data to find the most optimal solution. "We
were able to analyze data up to 2008 and predict where schools should be
closed in the region and we've been fairly accurate," says Delmelle. By
assigning an optimization value to every school, the team was able to
predict, for the most part, which schools would be closing and where
new ones should be built. His team was also able to help recommend adding more modular classrooms to help meet the increasing school
demand, to keep classroom size stable while the new schools are built.
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| A Graphic Depicting the Work Delmelle Has Done to Help Place Schools in the Best Locations |
A
similar approach was conducted to identify bus stops redundancy in
Charlotte. Delmelle collaborated with the Charlotte Area Transit System
(CATS) helping to tackle where the best locations for each bus stop
would be, using the optimization of individual accessibility and low operating costs as their
main objectives. "The city took great care to listen to our research," Delmelle said. Currently, Delmelle and his students are also evaluating accessibility to
public parks with Mecklenburg County by different modes of
transportation (car, public transit, biking, walking). These results
will inform park decision makers on where to locate new parks and which
ones are in immediate need to upgrading its amenities. The next venture
into help the Queen City would be to help optimize the new bike racks
the city has placed. "We just received some of the data and it's all
fairly new, so now we can run simulations to see where the best new
places to expand would be," says Delmelle, rather excited by the problem.
