IEEE Technology and Society Magazine - Winter 2013 - 54

Register Service

OSN Platform
Web Interface

Browse Services

Sensor Network
Managers

Developers

Store Data

API
REST
WS

OSN Platform
Core Engine

Sensor Networks

API
Consume Data
REST
WS
Apps and Mashups

OSN Platform
Data Base

Fig. 1. Open Sensor Data Platform scheme.

Norwegian governments or the panEuropean PublicData.eu, use the
Comprehensive Knowledge Archive
Network - CKAN - as the OpenSource software platform for support
[22]. This platform, developed in
2007 by the Open Knowledge Foundation (OKFn), is a public registry
of datasets and metadata. A CKAN
platform provides several features for
publishing and finding datasets, storing and managing data and metadata,
and customizing and extending them
through APIs. CKAN is becoming a
de facto standard in the Open Data
community, providing a stable platform to support most public and private project initiatives.
The Open Sensor Data Platform
of the Open Cities Project
The categorization of Open Data is
crucial for its future, and here we
will use the same categories as they
were defined and used in the Open
Cities Project [7]:
a)
b)

Arts and recreation,
Business Enterprise, Economics, and Trade,
City Budget: revenues and
Expenditures,

c)

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d) City Portal web Statistics,
e) Construction, Housing, and
Public works,
f) Crime and Community Safety,
g) Demographics,
h) Education,
i) Elections,
j) Emergency Services,
k) Energy and Utilities,
l) Environment, Geography and
Meteorological,
m) Health and Disability,
n) Labor Force and Employment
Market,
o) Law Enforcement, Courts, and
Prisons,
p) Political,
q) Tourism,
r) Urban Transport,
s) Others.
The Open Sensor Data platform
was built deploying a NO-SQL
database following the guidelines,
which fulfill the requirements of
dynamic sensor data. Apache Tomcat acts as an application server and
is connected to a CKAN instance.
A CKAN reference database has
been deployed to store metadata. The
CKAN platform is continuously up
to date with the already registered

services (datasets) of the Open Sensor Data platform, and it offers general information about the services
(metadata) and points towards the
Open Sensor Data platform [23].
XML and JSON are the selected
formats for publishing data through
a web service in a standardized
format. Since wSNs are allowed
to send their data using CSV messages, the platform translates them
to XML or JSON, as it allows an
easier creation of new apps.
To promote this reuse, we implemented the standardized web service called rEpresentational State
Transfer (rEST) that resolved platform connectivity to the data consumer. Now applications only need
to invoke services calling for their
metadata information and use rEST
service to access the datasets [24].
The architecture of the Open
Sensor Data Platform is shown
in Fig. 1. The platform provides
a front-end to the sensor network
manager who registers a service,
and offers a complete description as
metadata. Measurements organized
into datasets are stored through the
platform API, which guarantees a
standardized connectivity. with

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wINTEr 2013
http://www.PublicData.eu
Table of Contents for the Digital Edition of IEEE Technology and Society Magazine - Winter 2013
