1. A unified smart city environment based on SOFIA’s
Interoperability Open Platform
Giada Landi1 , Giorgio Laura2 , Vincenzo Memeo1 , Paolo Pucci2 , and Stefan Rapp3
1
Nextworks, via Turati 43/45,
56125 Pisa, Italy
{g.landi, v.memeo}@nextworks.it
2
Elsag-Datamat, via Laurentina 760,
00143 Rome, Italy
{giorgio.laura,paolo.pucci}@elsagdatamat.com
3
Conante, Fellenoord 130,
5611ZB Eindhoven, The Netherlands
rapp@conante.com
Abstract. The purpose of the poster is to show main results we obtained during
the first year of the SOFIA Project, a three-year ARTEMIS project started in
January 2009, led by NOKIA and involving eighteen partners from four different
EU countries. We focus on the application area related to smart city spaces and,
in particular, on the Unified Monitoring and Video Surveillance system built on
the common semantic Interoperability Open Platform developed in SOFIA.
Keywords. Video Surveillance, Wireless Sensor Networks, Smart Systems, In-
teroperability Platform
1 Introduction
The SOFIA project, a three-year ARTEMIS project started in January 2009 and in-
volving partners from four different EU countries, is built around the concept of smart
environment, intended as an ecosystem of interacting objects – e.g. sensors, devices,
appliances and embedded systems in general – able to self-organize, offer federated
services and process or provide complex data.
The mission of the SOFIA project is to create a semantic interoperability platform
and a selected set of vertical applications to form smart environments based on em-
bedded systems. The key factors in these smart environments will be an open and dis-
tributed information storage and common search procedures for all the embedded sys-
tems, implemented with different specific technologies. In this vision, local mash-up
applications will be built on open data and using a range of devices.
The motivations behind this approach are twofold: (i) connecting the real physical
world with the information world enriches the user experience and (ii) an Interoperabil-
ity Open Platform (IOP) will foster innovation and will guarantee the future evolution
of smart environments based on embedded systems, both from a scientific/technological
point of view and in terms of business.

2. With these concepts, SOFIA proposes an Internet-like revolution in physical space,
aiming to make “embedded information” in the physical world available for smart ser-
vices – connecting the physical world with the information world. Outcomes of the
project encompass (i) new user interaction paradigms for interacting in smart environ-
ments, (ii) a common multi-vendor interoperability solution between many new and
legacy heterogeneous devices and embedded systems, and (iii) application develop-
ment schemes, ontologies and tools that can mobilize new developers for smart envi-
ronments. The project addresses three application areas or “verticals” which represent
different kinds of space – in terms of scale, potential applications and services: smart
personal spaces (e.g. car), smart indoor spaces (e.g. home and office), and smart city
spaces (e.g. extended infrastructure and facilities like a subway station, shopping mall
and so on).
2 Smart Spaces in the SOFIA concept
In SOFIA, a smart space is an information search extent where semantic information is
presented in the form of an ontology graph or, equivalently, of triples (subject-predicate-
object). Semantic Information Brokers (SIBs) are the information stores of the smart
space. They provide a service interface for agents known as Knowledge Processors
(KPs). KPs can access the information within the smart space by connecting to the SIB
and invoking the operations offered by the Smart Space Access Protocol (SSAP) inter-
face. Through SSAP operations, KPs can perform session management (join, leave) and
triple governance transactions (insert, remove, update, query, subscribe, unsubscribe)
in order to insert new information into the smart space, remove obsolete or otherwise
undesirable information from the smart space, retrieve specific data on-demand and be
dynamically notified of the changes in the information content of the smart space by a
subscription/notification mechanism.
A KP, that has discovered a smart space it wants to interact with, must first join the
smart space by sending it its credentials. If the access control policies are met, the KP is
allowed to establish the connection. Service discovery is accomplished using the mech-
anisms available at the service level (e.g. NoTA [1]). To enable their reactive behaviour
the KPs make subscriptions in the smart space. The subscriptions are persistent queries
that notify the subscribing KP every time that the query results change. This allows
the KP to react appropriately and timely to changes in the smart space, while avoiding
unnecessary communication [2].
Depending on its behaviour, a KP can be a producer KP (i.e. a KP able to generate
new information and insert them into the SIB), a consumer KP (i.e. a KP able to retrieve
and react on specific information from the SIB through queries or subscriptions) or both
at the same time. The complete SIB interface is a union of the consumer and producer
interfaces.
3 The Unified Monitoring and Video Surveillance system
This section reports on the results achieved in the application areas related to Smart
City spaces, focusing in particular on our Unified Monitoring and Video Surveillance

3. (UMVS) system. Among other possible scenarios, the subway station has been selected,
as it is (i) a public and densely populated area, that needs to be continuously and ef-
fectively monitored through heterogeneous and distributed sensors and video cameras
and (ii) a dynamic environment with several categories of users (passengers, operators,
security staff) interested in different events to be delivered at the right time.
Some solutions have been proposed in the past for event detection based on Wireless
Sensor Networks (WSNs) [3] and video surveillance [4]. The SOFIA IOP enables the
combined processing of both WSN and video surveillance data resulting in a more
efficient event detection. This concept is the starting point for our UMVS architecture.
The UMVS architecture follows a multi-layer approach and is based on a common,
distributed UMVS middleware1 able to generate heterogeneous low-layer data, called
raw events, that describe various aspects of the surrounding environment. They are
combined into a set of complex higher-layer information, called composite events, and
made available to the UMVS application layer through the SOFIA IOP.
The UMVS middleware includes two types of modules: the producers of the raw
events and the data correlators (UMVS Event Managers) in charge of processing the low
level data in order to produce more detailed events. Currently the raw events originate
from producer KPs such as Closed-Circuit TV (CCTV) servers handling video cameras
distributed in a large area, or WSNs characterized by different kinds of sensors (e.g.
temperature, smoke, presence) , but the UMVS middleware can be easily extended in
order to support further data sources, including third-party services.
The information flow of our UMVS system is described through a structured on-
tology. The main advantage of this approach is, that although a uniform mechanism is
used throughout, individual subsystems can be treated separately. For example, the KPs
inside the CCTV server and the WSN managers need to adhere to only a fraction of the
ontology and need not be concerned about the rest. This is helping the implementation
on resource-constrained devices, and at the same time is beneficial for the extensibility
of the system. The data exchange among all the UMVS modules, as well as the con-
sistency and the synchronization of the information stored in the SIBs, relies on the
SOFIA IOP mechanisms.
At the top of the UMVS architecture, the application layer includes interactive mod-
ules that inform the users of events or alerts and allow them to trigger further actions.
All the UMVS applications interact with the SOFIA IOP in order to receive and exploit
the data provided by the UMVS middleware, including both raw and composite events.
On the other hand, some trusted applications are also able to insert into the SIBs some
specific events (i.e. alerts), so that they can be propagated towards their own peers, or
commands (i.e. configuration parameters or pan/tilt/zoom (PTZ) commands) to trigger
some specific actions in a given device. The UMVS applications provide services for
various user groups, characterized by specific roles and enabled to perform different
activities, depending on their user profile and the associated access policies.
The UMVS application layer comprises a set of applications deployed on a variety
of mobile and stationary devices. Central to the UMVS is a monitoring station applica-
tion that allows “first-level operators” to visualize all the events and alerts exchanged
1
“Middleware” is intended simply from an application point of view, since this layer hides from
the application-layer details about low-level information and related processing.

4. through the UMVS middleware, generate new alerts, and send configuration commands
to the WSN managers and the CCTV server. The monitoring station also receives video
streaming directly from the CCTV server, bypassing the IOP for performance reasons.
“Second-level operators” use a mobile or wearable device to receive a subset of the
events/alerts generated by the system and to generate a subset of alerts addressed to
other operators. Mobile devices with sufficient resources can interact directly with the
CCTV server to receive video streams and control remote PTZ cameras. A third type of
UMVS applications deals with users that need to be informed of exceptional events such
as an evacuation order. In this class, there are modules that change the public displays
accordingly, but also commercial signage displays are integrated into the emergency
signalling. They switch to a pre-programmed alternative content that leads passengers
more prominently to the emergency exits than it is possible with traditional signs. Fi-
nally an UMVS application informs passengers with suitable personal mobile devices
of an evacuation order by sending a broadcast message to them (e.g. RSS feeds).
4 Summary
We presented a unified system for monitoring and managing a public space, based on
a middleware managing heterogeneous data sources through an Interoperability Open
Platform (IOP) that uses a semantic description framework and access policies. The
IOP is openly developed in the SOFIA consortium and a first version is accessible from
sourceforge [5].
Acknowledgments
This work was funded by the European Commission, within the framework of the
ARTEMIS JU SP3 SOFIA project (http://sofia-project.org/). The authors would like
to thank all project partners who contributed to the definition and implementation of
SOFIA Open Innovation Platform.
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