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1 parent 1cc53b0 commit e39619dfcbd29c38026ea7a637ba3d3e6dec0948 Michael Schultz committed Dec 10, 2010
Showing with 135 additions and 25 deletions.
  1. +11 −0 doc/paper/report.bib
  2. BIN doc/paper/report.pdf
  3. +123 −25 doc/paper/report.tex
  4. +1 −0 src/frontend/
@@ -42,6 +42,17 @@ @Inproceedings{ pautasso:restful
address = {New York, NY, USA},
+@InProceedings{ lin:vision-parking,
+ author={Sheng-Fuu Lin and Yung-Yao Chen and Sung-Chieh Liu},
+ booktitle={International Conference on Systems, Man and Cybernetics, 2006},
+ title={A Vision-Based Parking Lot Management System},
+ year={2006},
+ month="Oct.",
+ volume={4},
+ number={},
+ pages={2897--2902},
+ doi={10.1109/ICSMC.2006.385314},
@Misc{ geomodel,
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@@ -115,23 +115,27 @@ \section{Goals}\label{sec:goals}
simple-to-interpret content?
-% from proposal
-%To achieve these goals, we intend to use the Tmote Sky/TelosB mote platform
-%which have an expansion connector that allows external sensors to be
-%To reduce installation costs, we will use a multi-hop routing protocol
-%(likely the collection tree protocol) to communicate data from a sensor to
-%the base station.
-%This allows for a large number of sensors to be deployed with little effort
-%or physical infrastructure to be in place.
-%Finally, once the data is aggregated at a central location it must be
-%displayed to the end user in an easy to read/interpret interface.
-%This is important because the vehicle operator needs to have a quick,
-%intuitive knowledge of where to go, so they don't cause physical
-%We also wish to monitor the duration of parking space use, to allow a
-%parking attendant to be notified when a person has overused their space.
-% end from proposal
+Our goals for the hardware involve prototyping a low cost, wireless system
+which can function with a heterogeneous sensor suite.
+This will be accomplished by using sensors with generic connection ports,
+allowing for customizing the system to different sensor methods with ease.
+Also, using
+the built in sensors on the motes, we plan to provide drivers with more
+advanced feedback than is traditional in parking structures, such as
+headlight detection.
+Lastly, our project will be adaptable for any current parking structure.
+Therefore, it must make use of the wireless capabilities of the mote
+platform, reducing the installation cost by negating the need for expensive
+Once our system has been installed, we plan to aggregate the data at a base
+station, located within the parking structure, which handles interactions
+between the WSN and the cloud.
+Communication between the base station and the network will rely upon
+Collection Tree Protocol (CTP), a robust method of point-to-sink wireless
+Our base station then communicates with a computer via serial port, which
+forwards the data to the cloud.
@@ -269,6 +273,22 @@ \subsubsection{A RESTful API}
identifies the Milbrook lot on Washington University's campus).
+ \begin{verbatim}
+ {
+ "space_id": 8,
+ "is_empty": false,
+ "magnet": 218,
+ "sonar": 114
+ },
+ ...
+ \caption{Client to server JSON data.}
+ \label{fig:clientserverjson}
Any request concerning this lot must go through its URI.
Requests use one of the HTTP verbs of \texttt{GET}, \texttt{PUT}, or
@@ -278,27 +298,93 @@ \subsubsection{A RESTful API}
This request contains the list of parking spaces to update, their
identification and status, as well as any associated meta-information that
-should be put in the datastore.
+should be put in the datastore, an example of this can be seen in
Finally, a \texttt{POST} request handles the creation of new parking lots.
With the API in place, we are able to create rich applications with ease
for expansion and integration into other software.
As a demonstration, we build up a web-based frontend in the next section
that takes advantage of our API.
-\subsubsection{Web Frontend}
+ \begin{verbatim}
+ "lot_id": "wustl_snowway",
+ "geo_pt": "38.650233,-90.313529",
+ "timestamp": 1291946695.0
+ "spaces":
+ [
+ {
+ "space_id": "4",
+ "is_empty": false,
+ "timestamp": 1291946695.0,
+ "extra_info": "sonar:55;magnet:201;"
+ },
+ ...
+ ]
+ \caption{Server to client JSON data.}
+ \label{fig:serverclientjson}
-Explanation of the frontend will go here.
+As mentioned above, a \texttt{GET} request on the parking lot identifier
+will result in either a HTML or JSON response.
+An example of the JSON response can be seen in
+The response provides enough information to a client application to
+identify the name of the lot, its location, the time of the most recent
+activity, and the list of spaces.
+Each space has a unique identifier, the status of that spot (full or
+empty), the time it was last updated, and any additional information about
+that spot (likely to be sensor readings at the last report).
+A client can combine this information with a virtual representation of the
+lot's topography, then keep that representation up-to-date by periodically
+querying the server for new information.
+For our project, we've also built an HTML interface for viewing the
+information on a lot.
+Once a lot is selected by the user, our interface provides a map of the
+area surrounding the lot with markers indicating other lots in a two mile
+It also displays a ``health'' indicator giving an approximate empty-to-full
+ratio, as well as a list of spaces that are filled and how long they've
+been filled.
+ \begin{center}
+ \includegraphics[width=\columnwidth]{figures/fullness-chart}
+ \end{center}
+ \caption{Example of a usage chart for the 5:30am--7:00am time slot.}
+ \label{fig:fullness-chart}
+Additionally, by keeping a log of changes to a lot on the backend, we are
+able to provide a chart to indicate the average fullness of a lot over a
+time frame.
+For example, Figure~\ref{fig:fullness-chart} shows the average fullness of
+the ``DUC'' lot from 5:30am until 7:00am.
+At the 6:06am time slot there are 11 spaces being used, however only 20
+minutes earlier only 6 spaces are being used.
+Having access to this information would allow a daily commuter, or one time
+visitor, discover that by arriving only 20 minutes earlier they would have
+a much greater chance of easily finding a parking space.
Paragraph about experiments that show our system works.
\section{Related Work}\label{sec:related}
-We are aware of two systems that target per-spot granularity.
-The first, Signal-Park, uses sonar sensors above each parking spot to
-detect the presence of a vehicle~\cite{pgi:signal-park}.
+There are other proposals and existing systems for parking guidance and
+information, here we'll discuss and differentiate ourselves from these
+Signal-Park, uses sonar sensors above each parking spot to detect the
+presence of a vehicle~\cite{pgi:signal-park}.
Approximately three times per second, the sensor is queried to determine
vehicle presences and updates a central computer.
This system uses serial lines to connect each sensor with the central
@@ -309,8 +395,8 @@ \section{Related Work}\label{sec:related}
to integrate with our back-end aggregation system to take advantage of
existing installations.
-The other system, Streetline, is a startup in the San Francisco area
-that similarly uses a wireless mesh network to link all the sensors
+Streetline, is a startup in the San Francisco area that similarly uses a
+wireless mesh network to link all the sensors
The Streetline system has recently (Summer 2010) begun to roll out sensors
and upgraded meters for select areas in the San Francisco
@@ -327,6 +413,18 @@ \section{Related Work}\label{sec:related}
We view this a positive, as it demonstrates that our project is a useful
idea with potential buyers available.
+There has also been a proposal to use existing security cameras with a view
+of a parking lot to detect vehicular presence~\cite{lin:vision-parking}.
+The results of their experiment, while decent for their scenario, seem
+unlikely to generalize to other systems.
+While it may be true that some lots have existing surveillance cameras, the
+paper also observes that cameras should be mounted higher for a more
+consistent and complete view of the lot.
+This goes against their principal of using existing cameras for the
+information, since additional cameras would have to be mounted to perform
+correctly (moving security cameras further from the observation area is
+probably not acceptable to the security officers).
\section{Lessons Learned}\label{sec:lessons}
Anything we would have done differently if we were to pursue this project
@@ -61,6 +61,7 @@ def space_list(min, max, items) :
host.request('PUT', '/lot/'+lotname, json.dumps(spaces))
+ print json.dumps(spaces)
resp = host.getresponse()
for space in spaces :

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