I am Partha Sarathi Paul. Now, I am presenting our MobileHCI 2020 paper titled “Disaster
Strikes! Internet Blackout! What’s the Fate of Crisis Mapping?” The authors are: Myself
Partha Sarathi Paul, Ankan Ghosh, Sujoy Saha, and Subrata Nandi from National Institute
of Technology Durgapur, India; and Bishakh Chandra Ghosh and Sandip Chakraborty from
Indian Institute of Technology Kharagpur, India. We present here a smartphone-based
offline crisis mapping system called SOTERIA. By offline, we mean that it works without
the presence of Internet. Basically, a crisis mapping system encodes disaster-specific GIS
information on a map of the affected area. By disaster-specific information, we mean
Drop zones, Helipads, Road blocks, Shelter points etc. Online crisis mapping systems
collect this information like Social Media and News channels. All of these need Internet.
But we know that the Internet often breaks down after disasters. In that case, crisis
mapping becomes difficult in the affected area. Here comes the Internet-less crisis
mapping systems like SOTERIA. We have conducted a thorough motivation survey: in the field
as well as online. From the field we have collected all together 155 feedbacks, 85 from
NGO members and 70 from Government officials. In online mode, we have collected 483 feedbacks.
By analyzing feedbacks, we find out a general opinion that there is a huge gap between the
crisis mapping infrastructures and the last-mile agents like the victims and the local volunteers.
What we observe is that there is general demand for a system for last-mile data collection.
Such systems should use off-the-shelf devices like smartphones. Such a system should also
provide seamless experience to the users, and should be non-obtrusive in the sense that
it should not hamper normal activities of the user. In addition, such a system should
have on-the-device data validation and GIS data summarization. It must be energy-efficient
to be used in a disaster situation. SOTERIA have features that kind of meet majority of
the above requirements. It uses smartphones, and some optional, precisely “optional”,
customized devices that we call Information Drop Box and Data Mule. The system acts following
a Delay Tolerant Ad Hoc Networking mode. The propagates through SOTERIA in a “Store-Carry-Forward”
manner. It has a self-contained Android application through which users can record and share text,
multimedia, and GIS messages. In order to share these messages, it requires minimal
user intervention; and so, it provides a kind of seamless user experience. In addition,
it provides with an automated on-the-device GIS summarization that we shall explain shortly.
Now here, in this slide, we show the component devices used in SOTERIA. The Android application;
Information Drop Box, which is a custom-built device to be placed at strategic locations
like shelter points etc.; and Data Mule, which actually are nothing but vehicles mounted
with Information Drop Boxes. The vehicles can be Ambulances, Police Cars, etc. The data
exchange takes place here if any pair of such devices come in close contact – like as
I have shown here in the slide. When the devices come contact, data exchange takes place, and
in this way, data moves from one place to another. This is the SOTERIA application architecture.
It is a two-tier architecture broadly. The back-end is the network management plane,
and the front-end is the user interface plane. The front-end is responsible for GIS and multimedia
data collection, data processing and storage, and generation of crisis map from that data.
The back-end is responsible for building opportunistic network using the component devices and data
sharing among these devices using the network. The bottom-most layer, P2PConnect, uses Wi-Fi
Direct for data transfer. To save energy, it uses acoustic-based signals for neighbor-discovery.
P2PSync, immediate on top of the previous layer, is responsible for sharing data using
P2PConnect. It employs a kind of best-effort data sharing, because, the connections here
are short-lived and intermittent. As far as the implementation is concerned, GIS system
is implemented using KML format. KML, which means Keyhole Markup Language. For GIS visualization,
we use OSMdroid, a free Android tool. We also have provided an end-to-end encryption of
messages based on PGP. Merging GIS objects is crucial in SOTERIA. We merge a pair of
GIS objects when they are spatially-collocated, they have near-identical textual metadata,
and they have near-identical structure or geometrical shape. Here, by spatial-collocation,
we mean that they share a common map tile of same zoom level. There near-identical metadata
can be compared using TF-IDF score. And their structure may be compared using Hausdorff
Distance Measure. If all the above three conditions are satisfied, then objects get merged like
we have shown in the figure side-by-side. For measuring performance, we have counted
the number of GIS objects present in a test node after each of its contact with other
nodes, and we see the number of GIS objects reduces if we use GIS summarization, and that
reduction is significant. That is quite promising. We also have measured the power dissipation
by the node, and we see that the acoustic based neighbor discovery improves the power
profile of the system. That is also good for our application scenario. We also have conducted
user survey with the devices, collected online feedbacks and in-field feedbacks by participating
in three mock disaster drills. We have significant number of feedbacks, both online and offline.
We have plotted here the feedback extracts against some important metrics like Simplicity
of the system, Usefulness of the system, Usefulness of the Summarization module, and the overall
System Rating. We find that around 50 to 80 percent of the feedbacks are positive; they
are even higher when the feedbacks are from mock drills. As a conclusion, we can say that
such a system a readily-deployable after a disaster, since it uses readily-available
off-the-shelf devices. The design is energy-aware. We have verified the above in the field and
in the lab, and also, we have conducted thorough user survey. As a future scope, we can say,
we assumed here that Internet connectivity breaks or destroyed completely after a disaster.
But that may not be case in reality. So, we may couple SOTERIA with online crisis mapping
systems, and integrate it with online social and news media as data sources. We may also
try sophisticated on-the-device GIS summarization techniques, which might improve the performance.
With this remark, we conclude here. Thank You.