An Android Based Mobile

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24 Νοε 2013 (πριν από 3 χρόνια και 6 μήνες)

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1

Approved For Public Release; Distribution Unlimited

Approved For Public Release; Distribution Unlimited


An Android Based Mobile

Heat Stress App


David Sauter

Atmospheric Modeling Applications Branch

Battlefield
Environment Division

Army Research Laboratory, WSMR, NM


david.sauter@us.army.mil

575
-
678
-
2078 [DSN 258
-
]

WIDA Conference
-

Mar 2012

US Army Research, Development

& Engineering

Command

2

Approved For Public Release; Distribution Unlimited

Approved For Public Release; Distribution Unlimited


Background


Hot Environment Assessment Tool
(HEAT) Overview


Inputs/Output


Validation Status


Summary

Outline


An Android Based Mobile Heat Stress App

3

Approved For Public Release; Distribution Unlimited

Approved For Public Release; Distribution Unlimited

Background (1 of 2)

Warfighter

Impacts:


Annual average of ~200 Army hospitalizations and 2 deaths due to heat stress
*


Individuals are more susceptible to heat stress after a heat stress incident


Potential for degraded training and mission execution

*

Carter, et al. Epidemiology of Hospitalizations and Deaths from Heat Illness in Soldiers.
Medicine and Science in
Sports and Exer
cise
2005
,
37
(8), 1338

1344.

http://www.skcinc.com/product_images2/755
-
56791.JPG


Issues:


Heat stress guidance not always available, especially
at lower echelons


Heat stress guidance generally based on Wet Bulb
Globe Temperature (WBGT) measurements which
require bulky instrumentation for accurate readings


4

Approved For Public Release; Distribution Unlimited

Approved For Public Release; Distribution Unlimited

Background

(2 of 2)

Solution:


Implement heat stress guidance on a variety of mobile computing devices using look
up tables (based on the WBGT) from a Joint Air Force/Army document
*


Require only simple readily available meteorological (e.g., via a handheld weather
sensor), work rate and clothing configuration inputs


Eliminate WBGT instrumentation dependency


*
Headquarters, Department of the Army and Air Force.
Heat Stress Control and Heat Casualty Management
. Technical
Bulletin 507, Air Force Pamphlet 48
-
154(I); Headquarters, Department of the Army and Air Force: Washington, D.C., 2003.

http://www.brighthand.com/assets/9093.jpg

5

Approved For Public Release; Distribution Unlimited

Approved For Public Release; Distribution Unlimited

Hot Environment Assessment Tool
(HEAT) Overview


Available on Personal Digital Assistant (PDA), Apple
iPhone
/iPod Touch and

Android
smartphone

and tablet devices


WBGT is computed via a physics based approach
*


Simple weather inputs from handheld weather sensor or other readily available source


Cloud amount and type entry from visual observation


Estimate the attenuated solar
insolation

for the location, date and time (required to
compute the globe temperature in the WBGT)
**


Display heat stress guidance in terms of work/rest cycle, maximum continuous work
time and required hourly water intake


Java implementation under the Android operating systems makes it relatively easy to
port from one device (e.g.,
smartphone
) to another (e.g., tablet)


Android version was recently evaluated by a Special Operations Team


formal report
to ARL shortly


*
Liljegren
, et.al. Modeling the Wet Bulb Globe Temperature Using Standard Meteorological Measurements
. Journal of
Occupational and Environmental Hygiene

2008
, 645−655.

**
Shapiro, Ralph. Solar
Radiative

Flux Calculations From Standard Surface Meteorological Observations, Air Force
Geophysics Laboratory
, AFGL
-
TR
-
82
-
0039, 1982.

6

Approved For Public Release; Distribution Unlimited

Approved For Public Release; Distribution Unlimited

Inputs (1 of 3)


SITE tab:


Latitude, longitude, date and time
required to compute solar position


If a GPS capability on the device, can
automatically assign default latitude and
longitude values


Set default date and time values from
the system values


Latitude and longitude values range
checked (as are all numeric inputs in the
app)



7

Approved For Public Release; Distribution Unlimited

Approved For Public Release; Distribution Unlimited

Inputs (2 of 3)


MET (“Meteorological”) tab:


Values currently manually entered


Kestrel handheld weather sensor used in
a recent Special Ops team evaluation


Bluetooth connection on the
mobile
device
and weather sensor should allow
for automated ingest of values except for
cloud info


8

Approved For Public Release; Distribution Unlimited

Approved For Public Release; Distribution Unlimited

Inputs (3 of 3)


WORK tab:


“Spinner” (drop down menu) for selecting
(standard) clothing and work choices


Qualitative descriptions (in military
terms) of each of the work levels


Allows for quick “what
-
if” calculations to
see results for different work and
clothing choices


May be able to add additional work and
clothing choices in a future release


9

Approved For Public Release; Distribution Unlimited

Approved For Public Release; Distribution Unlimited

Output (1 of 2)


RSLTS (“Results”) tab:


Work/Rest Cycle (based on 60 minute
period) in minutes


Continuous “one time” work duration
time after which Soldiers must be given
an extended recovery time, preferably in
the shade


Water intake requirement provided for
both work/rest cycle and continuous
work times


May be able to add additional work and
clothing choices in a future release


10

Approved For Public Release; Distribution Unlimited

Approved For Public Release; Distribution Unlimited

Output (2 of 2)


INFO tab:


Information on app version and
developer point of contact


11

Approved For Public Release; Distribution Unlimited

Approved For Public Release; Distribution Unlimited

Validation Status


Guidance from Joint pub lookup tables related to weather is essentially a function of
the WBGT, thus need to ensure the WBGT prediction is accurate!


United Kingdom Meteorological Office (UKMO) has provided ARL with results from a
WBGT measurement study for 4 geographic locations


A validation version of HEAT was developed to display the 2 calculated WBGT
components


natural wet bulb (
T
w
) & globe temperature (
T
g
)


as well as the WBGT


WBGT,
T
w
, and
T
g

will be compared to the UKMO measured values


To date, 50+ comparisons have been completed


All but 2 WBGT predictions are within 1 deg C of UKMO measured value


Preliminary results are encouraging, however, will

need to perform many more evaluations to be

statistically significant!

12

Approved For Public Release; Distribution Unlimited

Approved For Public Release; Distribution Unlimited


Mobile versions of HEAT can provide critical heat stress
guidance at lower echelons and in training environments


The WBGT computation eliminates the requirement for costly
WBGT instrumentation


A recent Special Ops team evaluation will hopefully provide
useful feedback


WBGT statistical evaluation to be completed in 2012


HEAT will be made available to the military pending outcome of
the
WBGT evaluation

Summary