Designing an HLA Federation Object Model for Atmospheric by dfsiopmhy6


									    Designing an HLA Federation Object Model for Atmospheric Dispersion
                             Dr. Richard Penney, Dr. John Carson, Dr. Peter Hoare,
                                                 QinetiQ Ltd,
                                    Malvern, Worcestershire, WR14 3PS, UK

                                                   Ian Griffiths
                                      Dstl Chemical and Biological Sciences
                                 Porton Down, Salisbury, Wiltshire, SP4 0JQ, UK

                                                Dr. Martyn Bull,
                                                RiskAware Ltd,
                        St Bartholomews Court, 18 Christmas Street, Bristol, BS1 5BT, UK

                                         Dr. Tom Stark, Carl Simchick
                                              Defense Group Inc,
                             2034 Eisenhower Ave, Suite 105, Alexandria, VA 22314

                                                 Donald Warf
                           Cubic Defense Systems Inc, East Coast Engineering Division
                               6915 Telegraph Road, Alexandria, Virginia 22310

                                                Walter Zimmers
                                        Defense Threat Reduction Agency
                                              Alexandria, Virginia

               Chemical, Biological, Simulation, HLA, BOM, FOM, EnviroFed, IMPACT, WALTS

ABSTRACT: There is currently considerable interest in modeling the effect of atmospheric dispersion of
chemical/biological agents in military scenarios. Both the US Defense Threat Reduction Agency (DTRA) and UK
MoD have programs which are studying the development and integration of a number of Chemical and Biological
(CB) software models. Two related activities being undertaken by these organizations are the DMSO-sponsored
Environment Federation, which this year includes CB effects and the DTRA sponsored Weapon Effects FOM
(WEFOM) group which is considering the wider use of CB models across US DoD.

The focus of this paper is to discuss how to make best use of DoD's High-Level Architecture (HLA) to achieve the
integration of atmospheric dispersion models, like the UK's UDM and US SCIPUFF model into HLA federations. This
integration involves taking inputs from source release model , e.g. the DTRA sponsored WALTS models, weather data
from meteorological servers, e.g. OASES, and finally feeding outputs into sensor or combat models like JointSAF.

However, this integration process demands that careful thought be given to the protocols by which physical
information about the dispersants is exchanged between the different types of models. This paper is intended to
stimulate discussion of these issues, particularly with a view to ensuring fair consideration of both the physics of the
dispersion process and the information conceptually required to be exchanged between various simulators.

The Environment federation has taken one approach to the integration of dispersion models into an entity level
simulation model, using JointSAF as the ultimate consumer of dispersion information. During the WEFOM meetings
different approaches for describing the transportation of the dispersion were produced which were formulated into
several BOMs[jc2]. There are also differences between the kind of data subscribing models require to visualize
dispersion and those that wish to stimulate detailed sensor models. The trade offs between the different approaches are
discussed in the paper, together with details of the practical experimentation undertaken to participate in the
Environment Federation.

                                                                 EnviroFed efforts, and DTRA’s involvement in the
1. Introduction                                                  EnviroFed III project is described in Section IV. In
                                                                 participating in the EnviroFed III project, DTRA
                                                                 provided expertise in developing a realistic WMD
Operating in its role as the DoD focal point for                 scenario, as well as the IMPACT and Weapons
weapons of mass destruction (WMD), The Defense                   Analysis and Lethality Tool Set (WALTS) simulations.
Threat Reduction Agency (DTRA) is the owner and                  IMPACT, which simulates hazard flow in both open
custodian of a variety of physics-based codes                    and urban terrains, is described in Section II. The
describing WMD-related phenomena. The use of these               WALTS simulation, which simulates the effects of
codes, which have been developed internally or as part           weapons on pre-defined targets, is also described in
of collaborative programs with other DoD and NATO                section II. The paper concludes with a brief conclusion
organizations, has traditionally been limited to the             that includes future directions.
direct support of the warfighting CINCs for the purpose
of, for example, counter-terrorism response, planning
strikes on WMD-related targets, estimation of collateral         2. Simulations
effects, and weaponeering. However, spurred by the
maturation of these codes and the prevalence of WMD-             2.1 IMPACT
related matters in current DoD and domestic response
planning, DTRA is leading an effort to make these                The Integrated Modeling Platform for Advanced
codes available for re-use. This effort is expected to           Computational Technologies (IMPACT) [MB1] is
make validated, realistic WMD environments available             being produced by the Defense Science and
across the gamut of DoD simulation domains, and help             Technology Laboratory (Dstl) for the United Kingdom
define requirements for future Chemical and Biological           Ministry of Defense (MoD). IMPACT is being
Defense M&S capabilities.                                        developed as the CB modeling calculation engine for
                                                                 the UK MoD’s Nuclear Chemical and Biological
This paper describes a snapshot of DTRA’s on-going               Battlefield Information System Application (NBC
efforts toward the goal of WMD simulation re-use.                BISA), which will be the future warning and reporting
The term ‘weapons of mass destruction’ generally                 system for the UK armed forces. An IMPACT
refers to chemical, biological, nuclear, or radiological         prototype has been developed as a proof-of-concept
weapons, or weapons involving high explosives. It                demonstrator to show that the system can incorporate
therefore follows logically that in order to simulate            state-of-the-art physics-based models and still provide
WMD effects, it is necessary to simulate the natural             real-time CB dispersion estimates. An example
environment, and the changes to the environment that             scenario modeled by IMPACT and visualized in a
are induced by these weapons. Thus, an important part            separate application is shown in figure 1.
of this effort has been to develop a reference Federation
Object Model (FOM), called the Weapons Effects
FOM (WEFOM, described in Section III), that seeks to
standardize the representation of the WMD-related
environment. DTRA’s work in this area has followed
that of the DMSO-led EnviroFed project, which has
utilized the SEDRIS Environmental Data Coding
Standard (EDCS) in order to provide a common
terminology set for describing the environment. This
has led to a natural synergy between DTRA and the
                                                                                                     Software Agent base class allows IMPACT to take
                                                                                                     advantage of the additional power of multi-processor
                                                                                                     hardware configurations where possible. Since all
                                                                                                     updates to the Dynamic Object Database are recorded
                                                                                                     to file, the system can restore its previous state easily
                                                                                                     after a system crash, and resume modeling. A rollback
                                                                                                     facility is also included, allowing the system to be
                                                                                                     returned to its state at any specified time.

                                                                                                     IMPACT incorporates the IMPACT Meteorological
                                                                                                     Preprocessor (IMP), which provides the local scale
                                                                                                     meteorological and wind field for the dispersion
                                                                                                     modeling. IMP can ingest gridded mesoscale national
                                                                                                     weather prediction (NWP) data or live weather station
                                                                                                     data or a combination of the two. IMP incorporates
                                                                                                     algorithms for calculating atmospheric boundary layer
       Figure 1: IMPACT Dispersion Visualization                                                     parameters required by the dispersion models. These
                                                                                                     are an implementation of the Environment Protection
The IMPACT architectural model grew out of the                                                       Agency (EPA) sponsored AERMET algorithms. IMP
requirement to integrate diverse collections of existing                                             also includes the Flow Across Complex Terrain Solver
modeling components together to create modeling and                                                  (FACTS) [IHG2], a fast wind flow model that is an
simulation applications, using a generic object-oriented                                             implementation of the Danish LINCOM model [IHG3].
architecture. The internal architecture chosen was                                                   The model solves linearised forms of the fundamental
based on the Blackboard Architecture, which is used in                                               governing equations for turbulent flows in the planetary
certain types of data fusion applications. In                                                        boundary layer. It conserves both mass and momentum
conventional blackboard architectures, several software                                              and in a matter of seconds it can predict a wind field
“agents” (autonomous modules) collaborate to solve a                                                 that incorporates the effects of terrain, morphology
problem by reading information from a “blackboard”                                                   (land usage) and atmospheric thermal conditions. The
database, and writing their conclusions back to the                                                  two main components of IMP are able to satisfy the
database. In the IMPACT architecture, a set of                                                       meteorological requirements of the dispersion models
modeling and gateway connectivity Software Agents                                                    within IMPACT.
collaborate to model dispersion, assess downwind
hazard and exchange information with other systems                                                   The IMPACT architecture is versatile enough to enable
(via HLA or otherwise). The software agents function                                                 the inclusion of a selection of different dispersion
autonomously, exchanging information via the                                                         models. The current IMPACT can include DTRA’s
Dynamic Object Database. Figure 2 provides a high-                                                   Hazard Prediction Assessment Capability (HPAC)
level overview of the IMPACT architecture.                                                           Second-order Closure Integrated Puff model
                                                                                                     (SCIPUFF) [IHG4], Dstl’s Urban Dispersion Model
                                     Software Agent                                                  (UDM) [IHG5] or an integrated version of the two
                                                                                                     dispersion models. (This integrated model was
                                                                                                     previously called CUSP, the Coupled UDM and
       Impact          Dispersion    Mean and Variance     Concentration       Hazard Assessment
                                                                                                     SCIPUFF, but this has recently been superseded by an
 Preprocessor Agent
                                     Concentration Time
                                       Series Agent
                                                            Time Series
                                                          Realisation Agent
                                                                                and HLA Gateway
                                                                                                     urban version of HPAC that incorporates the UDM.)

Dynamic Object Database
                                                                                                     SCIPUFF is a Gaussian puff model capable of
                                 Terrain     Dispersion
                                                                          Time Series     Source
                                                                                                     providing estimates of both the concentration mean and
                                Wind Flow      Output
                                                           Time Series
                                                                          Realisations   Locations   variance and probabilistic estimates that include the
                                                                                                     uncertainties of meteorology and small-scale
        Figure 2: IMPACT Architecture Overview                                                       atmospheric turbulence. The model can provide
                                                                                                     estimates of dosage and deposition as well as the
The architecture is highly modular, allowing software                                                concentration field.
agents to be developed independently and tested in
isolation, before being integrated together with relative                                            The UDM is a Gaussian puff model designed to handle
ease. The support of multi-threading within the                                                      dispersion within urban environments. It is a semi-
                                                                                                     empirical model based on a large number of urban
experiments conducted in a boundary layer wind               including the rapid fluctuations and intermittency
tunnel. The model is computationally very fast, capable      resulting from the turbulence in the wind field. At
of providing dispersion estimates of releases in urban       present, a Markov Chain Monte Carlo approach is
areas consisting of tens of thousands of buildings           utilized, but current work involves the use of a spectral
significantly faster than real time. It provides estimates   synthesis approach, which will allow sets of time series
of the concentration and dosage fields and can also          with physically realistic spatial and temporal
estimate the concentration within buildings through an       correlation to be generated.
integrated building infiltration model. Figure 3 shows
the results from an example release in an urban area                                      7.00E-04
modeled by the UDM. The UDM is currently the                                              6.00E-04
subject of a major validation effort (e.g. [IHG6]) and it

                                                                 Concentration (kg m-3)
was used together with SCIPUFF as part of DTRA’s                                          4.00E-04
research support for the 2001 US Presidential
Inauguration [IHG7].


                                                                                                     -145    -130     -115      -100     -85    -70    -55     -40       -25    -10
                                                                                                                                        Relative Tim e (s)

                                                                                           Figure 4: Mean Concentration Time Series


                                                              Concentration (Kg m-3)






                                                                                                     -60    -55     -50   -45     -40     -35   -30   -25    -20   -15    -10    -5   0
Figure 3: UDM Dispersion Output for Urban Area                                                                                          Relative Time (s)

IMPACT also includes functionality to utilize the
dispersion model output to calculate concentration time        Figure 5: Concentration Realization Time Series
series for sample locations within the simulation space.
These sample points may be fixed or moving. A two            An effects contouring module has been included,
stage approach is utilized:                                  primarily to provide a simple data construct for other
                                                             federates to visualize. The effects contouring module
In the first phase, discrete time series for ensemble        first makes a rapid assessment of the spatial region
mean concentration and concentration variance are            currently affected by the dispersing plume. It then
calculated for each sample location. The gaussian puff       calculates a two-dimensional grid of concentration
output data from the dispersion models is utilized for       values over the affected region. Finally, an appropriate
this calculation. An output sample interval of 5 seconds     concentration threshold is applied, and the shape of the
is usually chosen. The output data is stored in the          region experiencing concentrations at this or higher
Dynamic Object Database, ready to be passed to the           levels is converted to a vector representation, then
HLA federation.                                              passed to the HLA federation.

In the second optional phase, the discrete concentration     The HLA gateway is implemented as a Software Agent,
mean and variance time series from step 1 are utilized       whose responsibility is to communicate with the HLA
to synthesize time series “realizations”, with smaller       federation, to add releases, meteorology and sample
sample rates, typically 5Hz. These time series               locations notified by the federation to the IMPACT
realizations are designed to resemble typical                Dynamic Object Database, and to report any output
concentration time series observed in field experiments,     from the dispersion modeling and assessment modules
which appears in the Dynamic Object Database back to
the federation.                                             In order to facilitate the application of DTRA’s core
                                                            weapon effects and WMD environment simulation
The HLA gateway uses a configuration file to control        capability into a wide variety of application areas,
interactions with other federates and includes the          DTRA initiated the development of a reference
concept of implementations, together these allow            Weapons Effects Federation Object Model (WEFOM).
IMPACT to be quickly tailored to the requirements of a
particular federation.                                      DTRA assembled a large WEFOM development team.
                                                            Representatives from DTRA proper, Defense Modeling
2.2 WALTS                                                   and Simulation Office; Simulation, Training, &
                                                            Instrumentation Command; Naval Surface Warfare
The Weapon Analysis and Lethality Tool Set                  Center, Ballistic Missile Defense Organization,
(WALTS) is a Defense Threat Reduction Agency                Dugway Proving Grounds, Sandia National Laboratory,
(DTRA) simulation to model weapons effects. This            John Hopkins University/Applied Physics Laboratory,
HLA compliant simulation allows credible physics-           Institute for Defense Analysis; Defense Science and
based weapons effects for virtual targets to be             Technology Laboratory (UK), to name but a few; along
distributed among an HLA Federation or offline              with a host of support contractors, own this effort.
analysts. Some of the key software components of            Their needs span the spectrum from use in operations,
WALTS are the munitions definitions, physics engine         training, analysis, experimentation, and acquisition
calculations, tools which allow CB contaminants to be       environments, and from the platform / single entity
integrated into the target, and the visualization of data   level through fully aggregated simulations.
relevant to the damaged target.
                                                            The structure of the Weapon Effects Federation is
WALTS munitions database includes over 50 of the            much like that of the Environment Federation. Both
most common JMEMS structural munition definitions.          federations have terrain and environment servers that
Among the physics engine calculations currently in use      simulate the dynamic changes to the terrain and
are cratering, penetration, internal blast, first order     environment, and then publish this information to the
fragmentation, external blast and contaminant               other federates. In addition, both federations utilize the
expulsion. Configuration tools for the virtual target       Synthetic      Environment       Data     Representation
allow the user to “place” CB contaminants in the 3D         Interchange Specification (SEDRIS) standard to foster
model on a per room basis. Any resulting internal blast     FOM agility. The WEFOM currently uses only the
code run on this model will then determine if an agent      SEDRIS Environmental Data Coding Standard (EDCS)
release occurs. Based on the calculated effects, a          because it offers a standardized code for specifying
damaged model is dynamically generated for 3D               terrain and environmental objects, attributes,
visualization. In addition to this 3D model, pressure vs.   interactions, and parameters. The other pieces of the
time and temperature vs. time information is also           SEDRIS specification, such as, the Data Representation
available to the other federates or the analyst.            Model (DRM) or the Spatial Reference Model (SRM),
                                                            are not being used at this time.
3. The Weapon Effects FOM
                                                            The actual construction of the WEFOM is based on the
3.1 WEFOM Introduction                                      Base Object Model (BOM) concept. The idea behind
                                                            the BOM concept is to produce object model
As stated earlier in the paper, the Defense Threat          components that are reusable. This enables FOM and
Reduction Agency was chartered to focus and integrate       SOM developers to leverage pre-built simulation OM
the DoD’s capabilities to combat the emerging               components for rapid development. Typically, BOM
Weapons of Mass Destruction threat. In addition to          components consist of object classes, interaction
developing the high fidelity, physics based codes,          classes, and any associated attributes, parameters, and
necessary to model the phenomena; DTRA has been             meta-data. The BOM concept is currently being
actively adapting these codes for use by other              studied within the Simulation Interoperability
simulations within DoD’s High Level Architecture            Standards Organization (SISO).
environment. Within this simulation world, DTRA’s
goal was to match their weapons effects modeling and        DTRA’s participation in last years EnviroFed III
simulation capabilities with the end users needs,           demonstration was the first test of the WEFOM
emphasizing weapons of mass destruction.                    development effort. That version of the WEFOM
                                                            contained but a small subset of all the available BOMs
from DSTL (UK), DTRA, and OASES. The success of             In reality, releases can take a variety of forms, e.g.
that initial demonstration confirmed the development        instantaneous, constant, atmospheric or ground based.
path taken by the WEFOM team. It also highlighted           In producing the BOM the decision was made to have a
areas where more work is needed.                            single interaction which could be specialized to
                                                            represent all forms of release rather than a hierarchy of
Future efforts will focus on the development of new         release interactions which could potentially lead to
BOMs and improving upon those already developed,            dangerous ambiguities.
assisting with the SEDRIS development effort to ensure
that it is capable of adequately supporting rapid,          3.2.2 Sensor BOMs
dynamic terrain changes, providing input to SEDRIS
EDCS to allow for a fuller representation of the hazard     Sensor BOMs provide federates with the capability to
environment, optimizing the hazard geometry for             monitor the effects of the dispersion cloud and receive
improved publication/subscription, and scalability          reports on contamination and dosage. Subscribing
issues.                                                     federates can then use these data to drive damage
                                                            models or gauge performance degradation for entities
3.2 Chemical Biological Dispersion in WEFOM                 exposed to the gas cloud.

As part of our work in WEFOM a number of Base               One central problem with developing a FOM or BOM
Object Models have been developed to provide HLA            for gas dispersion is how to represent the physical
federates with the capabilities of modeling chemical or     characteristics of a gas cloud in HLA terms. While the
biological warfare in a synthetic environment.              HLA is very good at capturing discrete values such as
                                                            vehicle locations and velocities, it is less well suited to
The BOMs were derived from a gas dispersion FOM             modeling the characteristics of an evolving dispersion
[jc1] developed to originally connect IMPACT to other       plume. Arguably gas dispersion is best represented
simulations. BOMs were developed in accordance with         mathematically as continuous fields whose description
the guidelines presented in [jc3] and developed using a     in discrete variables is neither well-defined nor
set of in house tools.                                      necessarily independent of the evolution of that field.

The BOMs have been categorized into three separate          In developing these BOMs it was decided that the
areas: 1) To allow the description of the characteristics   simulation modeling gas dispersion should not publish
of a chemical or biological agent release into the          its own internal representation of the gas cloud, as it is
environment. 2) Allowing federates such as Stealth          principally an internal design decision that determines
Viewers to visualize the resulting gas plume 3)             how the simulation should translate this discrete
Providing a mechanism for federates to measure              representation into the properties of the gas at a
contamination or dosage levels at particular points in      particular point of interest.
the virtual space.
                                                            To this end a number of sensor BOMs are defined
In the following sections we describe these different       which correspond broadly to the types of sensor found
categories of BOMs in more detail.                          in operational usage, such as a point or grid based
                                                            sensors, or stand off sensors, such as a laser based
3.2.1 Agent Release BOM                                     system. In this hierarchy of sensors entities such as
                                                            personnel or vehicles can be considered as a
The Agent Release BOM defines an interaction and set        specialized case of point sensor. The Visualization
of Complex Types to capture the properties of a             BOM, discussed below, also corresponds to the sensor
dispersant agent as it enters the atmosphere.               model. Federates that wish to visualize the cloud
                                                            produce a pseudo-sensor which is updated with puff
The interaction allows a federate to specify a variety of   data as the cloud evolves.
factors such as the location of the release, the type of
agent involved, the mass, release dynamics as well as       The various types of sensor are modeled as a hierarchy
particle sizes.                                             with Complex Types that allow the characteristics of a
                                                            particular sensor, for instance sensitivity to particle
An Agent Release interaction is used as a cue to            size, to be specified. It should be noted that the sensor
IMPACT to start modeling the dispersion of the agent.       BOMs do not attempt to model real world sensor
                                                            systems, the readings returned to subscribing federates
are “perfect” in so far that they represent an insight into   EnviroFed III consisted of a number of excursions
what the dispersion model determines to be the status         centered around an assault on Camp Pendleton in San
of the cloud. Federates that wish to model the                Diego County. The scenario envisaged a sea assault by
characteristics of real world sensors can subscribe to        blue forces against red forces defending the airfield.
these data and then manipulate the data to model              The various excursions allow the impact of
probability of detection and so forth.                        environmental changes to be assessed on mission
3.2.3 Visualization BOMs
                                                              In one particular excursion a JSAF F-18 identified a
Most dispersion plumes resulting from a CB release are        bunker close to the airfield as a target of opportunity.
invisible to the human eye but in the realm of synthetic      Unknown to blue forces the bunker contained a
environments there is often a need to visualize the           chemical warfare agent. As the excursion progressed,
cloud to determine ground truth and drive Stealth             an incoming round penetrated the storage bunker,
displays.                                                     causing expulsion of the chemical agent. The data
                                                              flows between the various federates in simulating this
The Visualization BOM defines a set of Object Classes         excursion is described below.
and Complex Types to allow geometrical
representations of the gas cloud to be transmitted to         IMPACT’s federate interactions are summarized in
subscribing federates.                                        figure 6:

The visualization is represented as a set of Gaussian
puffs heuristically derived from the simulation’s                                    OASES
                                                                          Met                       Met
internal representation, which may typically be a puff-                                             Data
based dispersal model. Each published puff can be
associated with a set of bounding planes to amputate                               Dosage Reports
parts of the puff; this functionality allows us to model            JSAF            Concentration      IMPACT
not only puffs but also the dispersant wakes that can                                 Contour
persist in the lee of buildings.
                                                                      Weapon                         Agent
                                                                      Target         WALTS           Release
4. Participation in EnviroFed III                                     Impact

Part of DMSO’s Integrated Natural Environment
Program, the Environment Federation (EnviroFed) is a               Figure 6: IMPACT Federate Interactions
project in the Environmental Integration/Experiments
Technology Area. From its start in 1999 EnviroFed has         JSAF is responsible for modeling the aircraft and
had a number of key aims[jc5]:                                reporting the weapon detonation of a 2000 pound bomb
                                                              on the top of the storage bunker.
•   Demonstrate the state-of-the-art with regard to the
                                                              This MunitionDetonation interaction is mapped by the
    representation of the natural environment in DoD
                                                              Agile FOM Interface (AFI) to a WeaponTargetImpact
                                                              interaction and is received by WALTS which begins to
•   Demonstrate the application of SEDRIS products
                                                              model the effects of the detonation on the structure of
    and HLA tools and processes to combat
                                                              the bunker. Upon receipt of this interaction WALTS
    simulations and environment simulations
                                                              begins to model the effects of the penetration and blast
•   Facilitate reuse of resulting environmental
                                                              on the bunker. WALTS takes into account the type of
                                                              munition, the fuse setting, the impact coordinates and
                                                              velocity vector of the weapon that has detonated to
IMPACT recently participated in the EnviroFed III
                                                              calculate the damage caused to the building. Figure 7
exercise which was helpful in the development and
                                                              below shows a 3D model of the damage inflicted on the
refinement of the BOMs discussed above. As a member
                                                              building by the detonation calculated by WALTS. This
of this federation IMPACT interacted with WALTS,
                                                              model was dynamically generated by WALTS as a
OASES[jc4] and JSAF to augment the environmental
                                                              result of the calculated damage.
model with chemical and biological effects during
several scenario excursions.
                                                           6. References
                                                           [jc2]     P. L. Gustavson, J. P. Hancock, M.
                                                                McAuliffe: “Base Object Models (BOMs):
                                                                Reusable Component Objects for Federation
                                                                Development” Paper 98F-SIW-034 Simulation
                                                                Interoperability Workshop Fall 1998.
                                                           [MB1] M. Bull: “Impact Design Study” Dstl Internal
                                                                Document, 18 December 2000.
                                                           [IHG2] F. Dunkerley: “FACTS LINCOM Technical
                                                                Documentation (Draft)” Risoe National Laboratory
    Figure 7: Collateral Damage to the Bunker                   report prepared for Dstl, May 2001.
                                                           [IHG3] P. Astrup, N. O. Jensen, T. Mikkelsen:
The WALTS physics engine internal blast code models             “Surface Roughness Model for LINCOM” Risoe
damage to the bunker and determines that the CB                 National Laboratory, 1996.
contaminants stored inside would have been released        [IHG4] R. I. Sykes et al: “PC-SCIPUFF Version 1.0
into the atmosphere. WALTS communicates this to                 Technical Documentation” Titan Corporation
IMPACT using the AgentRelease BOM, detailing the                report prepared for DTRA, 1997.
type of agent released, for example, VX nerve gas, and     [IHG5] D. J. Hall, A. M. Spanton, I. H. Griffiths, M.
environmental factors such as the velocity of the               Hargrave, S. Walker: “The UDM – A Model for
release.                                                        Estimating Dispersion in Urban Areas” Envirobods
                                                                Ltd report prepared for Dstl, August 2000.
On receipt of the AgentRelease interaction IMPACT          [IHG6] I. H. Griffiths, N. V. Beck, C. John, D. J. Hall,
begins modeling the evolution of the gas plume                  A. M. Spanton: “The Results of an Initial
resulting from the release. Factors such as                     Validation Study of an Urban Dispersion Model”
meteorological conditions, terrain type and interactions        American Met. Soc. Third Symposium on the
with surrounding buildings are all used as inputs into          Urban Environment, Davis, CA, August 2000.
the modeling process.                                      [IHG7] J. Pace, I. H. Griffiths, R. I. Sykes, M.
                                                                Phillips, J. Hodge, K. Kim: “Capabilities of DTRA
The meteorological data subscribed to by IMPACT                 Urban Modeling during Presidential Inauguration
includes wind speed and direction as well as data               Support” 5th Annual George Mason University
regarding cloud coverage and ground surface                     Transport and Dispersion Modeling Workshop,
temperature. These data are processed by IMPACT’s               July 2001.
meteorological model to build a description of the wind    [jc1]     R. Penney, P. Hoare: “Towards an HLA
conditions over the terrain and transports the plume            Federation Object Model for Atmospheric
downwind.                                                       Dispersion Modeling” Internal QinetiQ report,
                                                                March 2001.
IMPACT subscribes to the locations of platform              [jc3] Base Object Model (BOM) Study Group:
entities controlled by JSAF. As the plume evolves               “BOM         Methodology      Strawman       (BMS)
dosages are calculated and reported back for any entity         Specification              Version             0.7”
that is exposed to the hazard. This data is used by JSAF
to drive damage models and degrade the performance              ?SISO_RID_1002220
of units exposed or in MOPP gear.                          [jc5]     R. Lutz et al.: “Envirofed Phase III
                                                                Demonstration Slides” November 8th 2001
JSAF can also request a contamination contour from         [jc4]     R. A. Reynolds, H. Iskenderian, S. O. Ouzts:
IMPACT, essentially a footprint of the plume, for               “The      Ocean,     Atmosphere      and      Space
display on the PVD. This capability was not provided            Environmental Services (OASES) System” Paper
in the original Gas Dispersion BOMs but added to                01S-SIW-047         Simulation     Interoperability
support EnviroFed.                                              Workshop Spring 2001.

                                                           Author Biographies
                                                           IAN GRIFFITHS has worked as a scientist at Dstl
                                                           Chemical and Biological Sciences for six years. He led
the research teams that developed the UDM and             to joining DTRA, Mr. Zimmers served 23 years in the
FACTS. He now heads the team that is producing            US Army as a helicopter pilot. He flew numerous
IMPACT as well as teams integrating the UDM with          combat and support missions in the Vietnam conflict
HPAC, producing operational hazard assessment             where he was awarded a Bronze Star, Purple Heart, and
systems and researching wind flow modeling                19 Air Medals.
particularly, most recently, at the land-sea interface.
                                                          RICHARD PENNEY is a Senior Mathematician at
MARTYN BULL is a senior software consultant at            QinetiQ Malvern UK, and has research interests that
RiskAware Ltd. Through his consultancy work with          cover mathematical modeling, signal processing and
Dstl Chemical and Biological Sciences, he has been        automatic routing. He studied physics at Oxford
involved with the development and integration of          University, and completed a DPhil there in theoretical
mathematical models for the CB theatre for five years.    physics on spin-glasses and neural networks. Since
He was the software architect for the IMPACT              joining QinetiQ (formerly DERA) in 1995, he has
prototype.                                                worked on problems encompassing synthetic
                                                          environments, submarine sonar-evasion, radar signal
PETER HOARE is a Principal Scientist in the               processing, and gas dispersion.
Distributed Technology Group at QinetiQ Malvern. He
received a BSc(Hons) and PhD degrees from Royal           DONALD WARF is a Software Engineer with Cubic
Holloway, University of London in 1988 and 1993           Defense Systems, Inc., Alexandria, VA, providing
respectively. He has been working in parallel and         support to DTRA. He has been involved in the
distributed simulation since 1993 and is the technical    integration of WALTS and IMPACT into the Envirofed
lead of several programmes in the UK researching the      Federation.
use of the DoD High Level Architecture. Also was also
a Drafting member of the HLA Standards Development        TOM S. STARK is a Senior Scientist at Defense
group developing the IEEE 1516 standards documents.       Group Inc. in Alexandria, VA. In this position, Dr.
                                                          Stark provides modeling and simulation, operations
JOHN CARSON is a scientist at QinetiQ Malvern.            research, and information technology support to the
Since joining QinetiQ (formerly DERA) in 1999 he has                                              s
                                                          Defense Threat Reduction Agency' Technology
worked on Command Information Systems and the             Development and Chemical and Biological Defense
HLA Interface to IMPACT. He has a PhD in parallel         Directorates. Prior to working for Defense Group Inc.,
architectures and languages and has worked in the field   Dr. Stark worked for Science Applications
of Synthetic Environments and prototyping underwater      International Corp. as part of the DMSO support team.
vehicles via simulation.                                  Dr. Stark holds Bachelors, Masters, and Doctoral
                                                          degrees in Physics, with a specialization in lasers and
WALTER ZIMMERS is Chief of DTRA’s Weapons                 quantum electronics.
of Mass Destruction Assessment and Analysis Center,
Counterproliferation  Support    and    Operations
Directorate. He has served in several operational
support positions in his 16 years at DTRA and
predecessor organizations, the Defense Special
Weapons Agency and Defense Nuclear Agency. Prior

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