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      <title-group>
        <article-title>Designing Emergency Response Pipelines : Lessons and Challenges</article-title>
      </title-group>
      <contrib-group>
        <aff id="aff0">
          <label>0</label>
          <institution>Stanford University</institution>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Vanderbilt University</institution>
        </aff>
      </contrib-group>
      <abstract>
        <p>Emergency response to incidents such as accidents, crimes, and fires is a major problem faced by communities. Emergency response management comprises of several stages and sub-problems like forecasting, resource allocation, and dispatch. The design of principled approaches to tackle each problem is necessary to create efficient emergency response management (ERM) pipelines. Over the last six years, we have worked with several first responder organizations to design ERM pipelines. In this paper, we highlight some of the challenges that we have identified and lessons that we have learned through our experience in this domain. Such challenges are particularly relevant for practitioners and researchers, and are important considerations even in the design of response strategies to mitigate disasters like floods and earthquakes.</p>
      </abstract>
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  <body>
    <sec id="sec-1">
      <title>Introduction</title>
      <p>
        Emergency response to incidents such as accidents, medical
calls, urban crimes, poaching, and fires is one of the most
pressing problems faced by communities across the globe.
Emergency response must be fast and efficient in order to
minimize loss of lives
        <xref ref-type="bibr" rid="ref2 ref3">(Jaldell 2017; Jaldell, Lebnak, and
Amornpetchsathaporn 2014)</xref>
        . Significant attention in the last
several decades has been devoted to studying emergency
incidents and response. The broader goal of designing ERM
systems is to enable communities to deal with emergency
response in a manner that is principled, proactive, and
efficient. ERM systems based on data-driven models can help
reduce both human and financial losses. Insights from
principled approaches can also be used to improve policies and
safety measures. Although such models are increasingly
being adopted by government agencies, emergency incidents
still cause thousands of deaths and injuries and also result
in losses worth more than billions of dollars directly or
indirectly each year
        <xref ref-type="bibr" rid="ref1">(Hattis 2015)</xref>
        .
      </p>
      <p>ERM can be divided into five major components: 1)
mitigation, 2) preparedness, 3) detection, 4) response, and 5)
recovery. The stages of ERM systems are heavily
interlinked (Mukhopadhyay et al. 2020). Mitigation involves
sustained efforts to reduce long-term risks to people and
property. It also involves creating forecasting models to
understand the spatial and temporal characteristics of
incidents. Preparedness involves creating policy and allocating
resources that enable emergency response management. The
third phase seeks to use automated techniques to detect
incidents as they happen in order to expedite response. The
dispatch phase, the most critical phase in the field, involves
responding to incidents when they occur. Finally, the
recovery phase seeks to provide support and sustenance to
communities and individuals affected by the emergency. While
most of the prior work in ERM has studied these problems
independently, these stages are inter-linked. Frequently, the
output of one stage serves as the input for another. For
example, predictive models learned in the preparedness stage are
used in planning response strategies. Therefore, it is crucial
that ERM pipelines are designed such that intricate
interdependencies are considered. In this paper, we highlight some
of the challenges that we have faced while designing ERM
pipelines and lessons that we have learned through the
process. A large portion of the insights have come from our
colleagues at the Nashville Fire Department and the Tennessee
Department of Transportation, who have provided
invaluable domain expertise to us.</p>
    </sec>
    <sec id="sec-2">
      <title>Challenges and Lessons</title>
      <p>
        While ERM forms a crucial component of the cities and
governments, designing and deploying principled approaches
to ERM is challenging. We consider the following to be
the main challenges in the design and deployment of ERM
pipelines.
1. How to forecast incident occurrence? It has been noted
that emergency incidents are generally difficult to
predict due to the inherent random nature of such incidents
and spatially varying factors (Shankar, Mannering, and
Barfield 1995; Mukhopadhyay et al. 2017). Incidents are
highly sporadic, making it particularly difficult to learn
models of incident occurrence. For example, well-known
regression models such as Poisson regression and
negative binomial regression have been shown to perform
poorly on accident data due to the prevalence of zero
counts (Mukhopadhyay et al. 2020). Incident data has also
been shown to be particularly sensitive to the scale of
spatial and temporal resolutions, thereby making it
difficult to perform meaningful inference. There are several
approaches that have shown to alleviate these concerns.
First, identifying clusters of incidents (both spatial and
non-spatial) has shown to balance model variance and
spatial heterogeneity particularly well (Sasidharan, Wu,
and Menendez 2015; Mukhopadhyay et al. 2017).
Second, dual state models like zero-inflated Poisson models
can be used to address the issue of a high number of zero
counts in data (Qin, Ivan, and Ravishanker 2004).
2. When to optimize? Arguably, the most important
component of ERM pipelines is to dispatch responders when
incidents occur. While resource allocation and dispatch
to emergency incidents evolve in highly uncertain and
dynamic environments, the expectation is that response
is very timely (Felder and Brinkmann 2002;
Mukhopadhyay, Wang, and Vorobeychik 2018). Approaches to
optimize dispatch typically focus on decision-making after
an incident occurs
        <xref ref-type="bibr" rid="ref4">(Toro-D´ıAz et al. 2013;
Mukhopadhyay, Wang, and Vorobeychik 2018; Keneally, Robbins,
and Lunday 2016)</xref>
        . However, our conversations and
collaborations with first responders revealed that there is
limited applicability of such approaches in practice due to
two important reasons. First, response to incidents occurs
almost instantaneously after a report is received. Although
optimizing dispatch can minimize response times in the
long run, time spent to optimize dispatch after incidents
occur is perceived as costly in the field. Second, it is
almost impossible to judge the severity of an incident from
a call for service. Consequently, it is imperative for first
responders to follow a greedy strategy and dispatch the
closest available responder to incidents. An alternative
approach is to periodically optimize the spatial
distribution of responders between incidents. Pettet et al. (Pettet
et al. 2020) introduced this idea recently for emergency
response. While there are challenges with respect to
scalability of such an approach, planning between incidents
is much more applicable in the field, as it does not violate
constraints under which first responder operate.
3. How to model communication? Approaches to tackle
emergency response typically assume that the agents can
observe the world completely and communicate with
centralized servers and each other. This assumption is usually
satisfied in practice. However, in scenarios that involve
natural disasters (like floods, earthquakes, wildfires, etc.)
communication mechanisms can break down and power
failures are common. In such scenarios, it is important that
agents can optimize response based on information
gathered locally. One way to approach such a problem is to
design distributed approaches for ERM, in which agents
can optimize their own decisions (Pettet et al. 2020). This
is feasible since modern agents (ambulances, for example)
are equipped with laptops. While distributed approaches
perform worse than their centralized counterparts, they
provide the benefit of performance in scenarios where
communication is challenging.
4. How to model the environment? A problem in
designing approaches to ERM is that environmental conditions
under which response takes place is dynamic. Consider a
decision-theoretic model for dispatching responders. For
example, see the semi-Markov decision process
formulation to minimize expected response times to accidents
(Mukhopadhyay, Wang, and Vorobeychik 2018). An
approach to solve such large-scale decision problems is to
use a simulator to find a policy that picks the optimal
action given the state of the world. However, in urban areas,
events like road closures, constructions, or increased
traffic due to a public gathering can drastically alter the
distribution of incidents. Further, ambulances can be
unavailable due to breakdowns or maintenance. In such cases,
it is crucial that the actual state of the environment is
taken into account while creating allocation and dispatch
decisions. One approach is to create high-fidelity
models of covariates such as traffic and weather. Such
models can then be used in online forecasting models, that
can accommodate incoming streams of updated
information (Mukhopadhyay et al. 2019). Similarly,
decisiontheoretic approaches that can quickly compute promising
actions for the current state of the world can be more
valuable in emergency response than approaches that find
policies for the entire state space of the problem (Pettet
et al. 2020).
      </p>
      <p>The principled design of ERM systems is an important
problem faced by communities. As smart and connected
communities evolve, they present both opportunities and
challenges to manage ERM systems. In this short paper,
we highlight common problems and lessons learned through
our experience in designing ERM systems over the last few
years.</p>
    </sec>
    <sec id="sec-3">
      <title>Acknowledgement</title>
      <p>We would like to acknowledge the National Science
Foundation and the Center of Automotive Research at Stanford
for funding this research. We would also like to thank the
Nashville Fire Department (NFD) and the Tennessee
Department of Transportation (TDOT) for collaborating with
us and providing invaluable knowledge about the intricacies
of emergency response.
Felder, S.; and Brinkmann, H. 2002. Spatial allocation of
emergency medical services: minimising the death rate or providing
equal access? Regional Science and Urban Economics 32(1): 27–
45.</p>
      <p>Pettet, G.; Mukhopadhyay, A.; Kochenderfer, M.; Vorobeychik, Y.;
and Dubey, A. 2020. On algorithmic decision procedures in
emergency response systems in smart and connected communities. In
International Conference on Autonomous Agents and Multiagent
Systems (AAMAS).</p>
      <p>Qin, X.; Ivan, J. N.; and Ravishanker, N. 2004. Selecting exposure
measures in crash rate prediction for two-lane highway segments.
Accident Analysis &amp; Prevention 36(2): 183–191.</p>
      <p>Sasidharan, L.; Wu, K.-F.; and Menendez, M. 2015. Exploring the
application of latent class cluster analysis for investigating
pedestrian crash injury severities in Switzerland. Accident Analysis &amp;
Prevention 85: 219–228.</p>
      <p>Shankar, V.; Mannering, F.; and Barfield, W. 1995. Effect of
roadway geometrics and environmental factors on rural freeway
accident frequencies. Accident Analysis &amp; Prevention 27(3): 371–389.
Toro-D´ıAz, H.; Mayorga, M. E.; Chanta, S.; and Mclay, L. A. 2013.
Joint location and dispatching decisions for emergency medical
services. Computers &amp; Industrial Engineering 64(4): 917–928.</p>
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