Sensor Networks and Ambiente Intelligence

Redes de Sensores em Ambientes
Inteligentes, ISMAI, 2013
F. Luís Neves <f.luis.neves@gmail.com>
Rui M. Barreira <rui.m.Barreira@gmail.com>

Program
1. Context and Application
2. Wireless Sensor Networks
(WSNs)
3. Ambient Intelligence in
Practice
4. Topologies and Protocols.
5. Development Platforms
6. Embedded and
Ubiquitous Computing
7. Context Awareness
8. Projecting Applications
supported by WSNs

1.
Context and
Applications
1. Ambient Intelligence
2. Core Problems and Challenges
3. Key Technological Areas
4. The User as the Center of the
System

The most profound technologies are those
that disappear. They weave themselves into
the fabric of everyday life until they are
indistinguishable from it.
The Computer for the 21st Century, by Mark
Weiser, 1991
A vision for our environment
Smart electronic environments that are
sensitive and responsive to the presence of
people;
Electronics embedded in every-day objects;
natural interaction; context aware;
personalized; adaptive; responsive; pro-active;
Enhancing productivity, healthcare, well-being,
expressiveness, creativity;
Intelligent user friendly interfaces.

Ubiquidade (ou omnipresença), ou seja, situações em que estamos
rodeados de conjuntos multifacetados de sistemas embebidos;
Precaução, ou seja, a capacidade para localizar e reconhecer objectos,
pessoas e intenções;
Inteligência, ou seja, capacidade de analizar o contexto, adaptar-se a esse
contexto e às pessoas que nele interagem, capacidade de “aprendizagem”
através do comportamento e do reconhecimento de emoções e da
interacção natural;
Utilização de meios de comunicação “naturais”, tais como a
reconhecimento linguístico e a consequente utilização da linguagem natural.
Principais
Conceitos

Ambientes inteligentes
Ambientes cooperativos
Edifícios inteligentes
Casas inteligentes
Redes móveis
Computação móvel
Interacção natural
“Os homens viverão em breve rodeados de ambientes
inteligentes através de interfaces inteligentes suportadas
por computadores em rede embebidos no nosso dia a dia
habitacional.”
Programa Europeu IST – Information Society Technologies
Pervasive computing (no sentido da presença tecnológica invasiva)
Ubiquitous computing (no sentido da omnipresença tecnológica)
Wearable computing (no sentido da “vestimenta” tecnológica)

• Qual o impacto social derivado da utilizado de
sistemas de AmI?
• Qual o seu verdadeiro potencial na melhoria da
qualidade de vida?
• Como se conjugam nestes ambientes os aspectos
relacionados com a privacidade e a confiança?
• Que características podemos encontrar nas diferentes
interacções possibilitadas pelos sistemas AmI?
Questões

• Qual o nível de inteligência que as
pessoas estão dispostas a aceitar?
• Como definir as diferentes dimensões do
termo “ambiente”?
• Como fazer refletir o design nos espaços
interactivos e nos artefactos inteligentes?
• Como fazer reflectir a utilização diária de
aparelhos na interacção implicita?
Questões

… it is not technological…
Understanding the functioning
of the physical, natural,
biological, cultural, technical
social reality that we live in.

Interdisciplinary Ambient Intelligence
Architecture
Design
Sociology
Anthropology
Cognitive
Science
Neuroscience
Psychology
Engineering

Ambient Intelligence
Intelligent
Interfaces
Ubiquitous
Communications
Ubiquitous
Computing
Ambient Intelligence started as…
Technology Integrator

What we have and what we need…
What we
Have
What we
Need
Integration
Scalable and Robust
Solutions
Business Models
Standards and Lead
Markets
Building blocks
Shared scenarios
Interdisciplinary
awareness
New practices of research
and innovation

Criticism and Social Impact
Social, Political and Cultural
concerns about:
The loss of consumer privacy
Fear for an increasingly individualized,
fragmented society
Hyper real environments where the virtual is
indistinguishable from the real
Welcome to a world through Glass
http://www.google.com/glass/start/
what-it-does

Social and Political aspects
Should facilitate human contact;
Should be orientated towards community and cultural
enhancement;
Should help to build knowledge and skills for work, better
quality of work, citizenship and consumer choice;
Should inspire trust and confidence;
Should be consistent with long term sustainability - personal,
societal and environmental - and with life-long learning;
Should be made easy to live with and controllable by
ordinary people.

Emblematic Projects
Philips
Homelabs

Emblematic Projects
Mit Media
Lab

Emblematic Projects
Home of
the Future
Bill and Melinda Gates' $97 million house
Home automation is defined as a process or system which provides the ability to
enhance one's lifestyle, and make a home more comfortable, safe and efficient.
Home automation can link lighting, entertainment, security, telecommunications,
office automation, heating and air conditioning into one centrally controlled system.

Market Trends

Ambient Intelligence Building Blocks
Ambient
Intelligence
Ubiquitous
Computing
Pervasive
Computing
Wearable
Computing
Mobile
Computing
Embedded
Systems
Personalized
Systems
Context
Awareness
Adaptive
Systems
Intelligent
Agents
Human-
Centric UIs

The User as the Center of the System
What is Usability?
Jakob Nielsen
Usability is the measure of the
quality of the user experience when
interacting with something -
whether a website, a traditional
software application, or any other
device the user can operate in
some way or another.

What is Usability?
ISO 9421
Usability is a measure of the
effectiveness, efficiency and
satisfaction with which specified
users can achieve specified goals in
a particular environment.

Putting People First
How to make informed (proactive) choices about
sharing information?
How to learn how other people protect their
information?
How to share information with an intended audience?
(e.g. friends, my family and their friends)
Much more than usability – What is the framework for
social communication?

Communication
Processes
• Social navigation
• Legitimate peripheral participation
• Social translucence
Structures
• Relationships
• Social networks

Support “peace of mind”Augment common
household object
Maintain awareness
over distance

2.
Wireless Sensor
Networks (WSN)
1. Origins
2. Hardware Platforms
3. Operating Systems
4. Networking
5. Security
6. Applications
7. Standardization

Wireless Sensor Networks
Origins
1958: Advanced Research Projects Agency (ARPA)
created by president Dwight D. Eisenhower.
1972: ARPA renamed to "DARPA" (for Defense)
1978: Technology components for a DSN were
identified (Proceedings of the Distributed Sensor
Nets Workshop, 1978):
• sensors (acoustic)
• communication and processing modules, and
• distributed software
1980: The origins of the research on WSNs
can be traced back to the Distributed
Sensor Networks (DSN) program at the
DARPA
DSNs were assumed to have many spatially
distributed low-cost sensing nodes that
collaborated with each other but
operated autonomously, with information
being routed to whichever node was best
able to use the information.

Origins
Initial Limitations:
• Size: sensors were rather large (i.e. shoe
box and up) which limited the number of
potential applications.
• Price: the earliest DSNs were not tightly
associated with wireless connectivity.
1988: New wave of research in WSNs mainly
focused on networking techniques and
networked information processing suitable
for highly dynamic ad hoc environments.
1990s: Appearance of sensor nodes:
• much smaller in size
• much cheaper in price
Many new civilian applications of sensor networks
such as environment monitoring, vehicular sensor
network and body sensor network have emerged.
2001: SensIT (Kumar & Shepherd) provided the
present sensor networks with new capabilities
such as ad hoc networking, dynamic querying
and tasking, reprogramming and multitasking.

Origins
2003: Institute of Electrical and Electronics
Engineers (IEEE) has defined the IEEE
802.15.4 standard which specifies the
physical layer and media access control for
low-rate wireless personal area networks.
2003: Based on IEEE 802.15.4, ZigBee
Alliance has published the ZigBee standard
which specifies a suite of high level
communication protocols which can be
used by WSNs.
Currently, WSN has been viewed as one of
the most important technologies for the
21st century (21 Ideas for the 21st Century,
1999).
Countries such as China have involved
WSNs in their national strategic research
programmes.
The commercialization of WSNs are also
being accelerated by new formed
companies.

2.
Wireless Sensor
Networks (WSN)
1. Origins
2. Hardware Platform
3. Operating Systems
4. Networking
5. Security
6. Applications
7. Standardization

Hardware Platform
Network: A WSN consists of spatially
distributed sensor nodes.
Each sensor node is able to independently
perform some processing and sensing
tasks.
Sensor nodes communicate with each
other in order to forward their sensed
information to a central processing unit or
conduct some local coordination such as
data fusion.

Hardware Platform
Sensor nodes: micro-electronic devices powered
by a limited power source. Because of that, the
attached sensors should also be small in size and
consume extremely low energy.
A sensor node can have one or several types of
sensors integrated in or connected to the node.
Memories in a sensor node include in-chip flash
memory and RAM of a microcontroller and
external flash memory.
A sensor is a hardware device that produces a
measurable response signal to a change in a
physical condition (e.g. temperature, pressure,
humidity). Sensor Node (typical) Architecture

Hardware Platform
Embedded Processor: the functionality of
an embedded processor is to schedule
tasks, process data and control the
functionality of other hardware components.
The Microcontroller has been the most
used embedded processor for sensor
nodes because of its flexibility to connect to
other devices and its cheap price.
Types of embedded processors that can be used in a sensor node:
• Microcontroller, a small computer on a single integrated circuit
containing a processor core, memory, and programmable I/O
peripherals
• Digital Signal Processor (DSP), a specialized microprocessor with an
architecture optimized for the operational needs of digital signal
processing (measure, filter and/or compress continuous real-world
analog signals)
• Field Programmable Gate Array (FPGA), an integrated circuit designed
to be configured by a customer or a designer after manufacturing and
which contains programmable logic components called "logic blocks"
• Application Specific Integrated Circuit (ASIC), an integrated circuit
(IC) customized for a particular use, rather than intended for general-
purpose use

Hardware Platform
Transceiver: A transceiver is responsible for
the wireless communication of a sensor node.
The various choices of wireless transmission
media include:
• Radio Frequency (RF)
• Laser and
• Infrared.
RF based communication fits to most of
WSN applications.
The operational states of a transceiver are:
• Transmit
• Receive
• Idle and
• Sleep.
ZigBee ZM-24 Transceiver Module, from RTI Corp.

Hardware Platform
Power Source: In a sensor node, power is
consumed by sensing, communication and
data processing.
More energy is required for data
communication than for sensing and data
processing.
Power can be stored in batteries or
capacitors.
Batteries are the main source of power
supply for sensor nodes.

Operating Systems
The role of any operating system (OS) is
to promote the development of reliable
application software by providing a
convenient and safe abstraction of hardware
resources.
OSs for WSN nodes are typically less
complex than general-purpose OSs both
because of the special requirements of WSN
applications and because of the resource
constraints in WSN hardware platforms.
TinyOS is an operating system specifically
designed for WSNs.
It features a component-based
architecture which enables rapid innovation
and implementation while minimizing code
size as required by the severe memory
constraints inherent in WSNs.
TinyOS’s component library includes
network protocols, distributed services,
sensor drivers, and data acquisition tools

Operating Systems
Contiki is another open source OS specifically
designed for WSNs.
The Contiki kernel is event-driven, like
TinyOS, but the system supports
multithreading on a per application basis.
Furthermore, Contiki includes protothreads
(lightweight threads) that provide a thread-like
programming abstraction but with a very small
memory overhead.
Contiki provides IP communication, both for
IPv4 and IPv6.

Networking
A WSN is a network consisting of numerous
sensor nodes with sensing, wireless
communications and computing capabilities.
These sensor nodes are scattered in an
unattended environment (i.e. sensing field) to
sense the physical world.
The sensed data can be collected by a few sink
nodes which have accesses to infrastructured
networks like the Internet.
Finally, an end user can remotely fetch the
sensed data by accessing infrastructured
networks.

Networking: Network Architecture
The protocol stack is an implementation of a
computer networking protocol suite.
The suite is the definition of the protocols,
and the stack is the software
implementation of them.
Protocol Layer
HTTP Application
TCP Transport
IP Internet/Network
Ethernet Data Link/Link
IEEE 802.3u Physical
Protocol Stack is a set of network protocol
layers that work together.
The term stack also refers to the actual
software that processes the protocols

Networking: Protocol Stack of WSNs
The sensor network protocol stack is much like the
traditional protocol stack, with the following layers:
• Application
• Transport
• Network
• Data link and
• physical.
The physical layer is responsible for frequency
selection, carrier frequency generation, signal
detection, modulation and data encryption.
The data link layer is responsible for the multiplexing of data
streams, data frame detection, medium access and error control.
It ensures reliable point-to-point and point-to-multipoint
connections in a communication network.
The network layer takes care of routing the data supplied by
the transport layer. The network layer design in WSNs must
consider the power efficiency, data-centric communication, data
aggregation, etc.
The transportation layer helps to maintain the data flow and
may be important if WSNs are planned to be accessed through
the Internet or other external networks.
Depending on the sensing tasks, different types of application
software can be set up and used on the application layer.

WSNs must also be aware of the following
management planes in order to function
efficiently:
• Mobility
• Power
• Task
• Quality of Service (QoS) and
• Security management planes.
The mobility management plane detects and
registers movement of nodes so a data route to
the sink is always maintained.
The power management plane is responsible
for minimizing power consumption and may
turn off functionality in order to preserve energy.
The task management plane balances and
schedules the sensing tasks assigned to the
sensing field and thus only the necessary nodes
are assigned with sensing tasks and the remainder
are able to focus on routing and data aggregation.

QoS management in WSNs can be very
important if there is a real-time requirement
with regard to the data services.
QoS management also deals with fault
tolerance, error control and performance
optimization in terms of certain QoS
metrics.
Security management is the process of
managing, monitoring, and controlling
the security related behavior of a
network.
The primary function of security
management is in controlling access
points to critical or sensitive data.
Security management also includes the
seamless integration of different security
function modules, including encryption,
authentication and intrusion detection.
It is obvious that networking protocols
developed for WSNs must address all five of
these management planes.

Security
While the future of WSNs is very
prospective, WSNs will not be successfully
deployed if security, dependability and
privacy issues are not addressed
adequately.
These issues become more important
because WSNs are usually used for very
critical applications.
Security Threats in WSNs: A typical WSN
consists of hundreds or even thousands of tiny
and resource-constrained sensor nodes.
In a basic WSN scenario, resource constraint,
wireless communication, security-sensitive data,
uncontrollable environment, and even
distributed deployment are all vulnerabilities.
These vulnerabilities make WSNs suffer from an
amazing number of security threats.
WSNs can only be used in the critical applications
after the potential security threats are eliminated.

Security
Physical Layer Threats: there are more
threats to WSNs in the physical layer, due to
the non-tamper-resistant WSN nodes and
the broadcasting nature of wireless
transmission.
Link Layer Threats: The data link layer is
responsible for the multiplexing of data
streams, data frame detection, medium
access, and error control.
Network Layer Threats: Threats in the network layer
mostly aim at disturbing data-centric and energy
efficient multihop routing, which is the main design
principle in WSNs.
Application Layer Threats: Many WSNs’ applications
heavily rely on coordinated services such as
localization, time synchronization, and in-network
data processing to collaboratively process data.
Unfortunately, these services represent unique
vulnerabilities (e.g. False data filtering; Clock un-
synchronization)

Security Countermeasures
Generally, countermeasures to the threats in WSNs
should fulfill the following security requirements:
• Availability, which ensures that the desired
network services are available whenever required.
• Authentication, which ensures that the
communication from one node to another node is
genuine.
• Confidentiality, which provides the privacy of the
wireless communication channels.
• Integrity, which ensures that the message or the
entity under consideration is not altered.
• Non-reputation, which prevents malicious
nodes to hide or deny their activities.
• Freshness, which implies that the data is
recent and ensures that no adversary can
replay old messages.
• Survivability, which ensures the acceptable
level of network services even in the
presence of node failures and malicious
attacks.
• Self-security, countermeasures may
introduce additional hardware and software
infrastructures

The typical countermeasures to the threats in
WSNs are the following:
• Key Management: When setting up a
sensor network, one of the first security
requirements is to establish cryptographic
keys for later secure communication. The
established keys should be resilient to
attacks and flexible to dynamic update.
• Authentication: the authentication of the
data source as well as the data are critical
concerns.
• Proper authentication mechanisms:
can provide WSNs with both sensor and
user identification ability, can protect the
integrity and freshness of critical data,
and can prohibit and identify
impersonating attack.
• Intrusion Detection: Security
technologies, such as authentication and
cryptography, can enhance the security
of sensor networks.

Privacy Protection: As WSN applications
expand to include increasingly sensitive
measurements in both military tasks and
everyday life, privacy protection becomes an
increasingly important concern.
For example, few people may enjoy the
benefits of a body area WSN, if they know
that their personal data such as heart rate,
blood pressure, etc., are regularly
transmitted without proper privacy
protection.

Applications
Military sensor networks, which includes:
• large-scale acoustic ocean surveillance
systems for the detection of submarines
• self-organized and randomly deployed
WSNs for battlefield surveillance
• attaching microsensors to weapons for
stockpile surveillance
Environmental Monitoring, which includes:
• animal tracking
• forest surveillance
• flood detection
• weather forecasting.
It is a natural candidate for applying WSNs
because the variables to be monitored are
usually distributed over a large region (e.g.
temperature).

Applications
Health Monitoring, which includes special kinds of
sensors which can measure, for instance:
• blood pressure
• body temperature
• electrocardiograph (ECG)
These sensors can even be knitted into clothes to
provide remote nursing for the elderly.
When the sensors are worn or implanted for healthcare
purposes, they form a special kind of sensor network
called a body sensor network (BSN).
Traffic Control, which includes, for instance,
the massive installation of cheap sensor
nodes:
• in the vehicles
• at the parking lots
• along the roadside
• etc.

Applications
Industrial Sensing, which typically includes the
possibility to monitor the “health” of machines and
to ensure safe operation.
For example, a network of wireless corrosion
sensors can be economically deployed to reliably
identify issues (e.g. aging pipelines and tanks in the
oil and gas industry) before they become
catastrophic failures.
WSNs have also been suggested for use in the food
industry to prevent the incidents of
contaminating the food supply chain. (e.g. using
temperature sensors to check refrigerated transport).
Infrastructure Security, which includes the
use of WSNs for infrastructure security and
counterterrorism applications.
Critical buildings and facilities such as power
plants, airports, and military bases have to
be protected from potential invasions.
Networks of video, acoustic, and other
sensors can be deployed around these
facilities.

Standardization
The major standardization organizations are:
• the Institute of Electrical and Electronics
Engineers (IEEE)
• the Internet Engineering Task Force (IETF)
• the International Society for Automation
(ISA) and the HART Communication
Foundation,
IEEE 802.15.4 is a standard which specifies
the physical layer and MAC layer for low-
rate wireless personal area networks.
It is the basis for the ZigBee and
WirelessHART specification, each of which
further attempts to offer a complete
networking solution by developing the
upper layers which are not covered by the
standard.

Standardization
ZigBee is a standard for a suite of high level
communication protocols based on the IEEE
802.15.4 standard for low power and low
data rate radio communications. Zigbee is
initiated and maintained by the Zigbee
Alliance - a large consortium of industry
players.
The typical application areas of Zigbee include:
• Smart energy monitoring
• Health care monitoring
• Remote control
• Building automation
• Home automation,
• etc.

Standardization
WirelessHART is an open-standard wireless mesh
network (WMN) communications protocol designed
to meet the needs for process automation
applications.
The protocol utilizes IEEE 802.15.4 compatible
DSSS radios and it is operating in the 2.4GHz ISM
radio band.
On the data link layer, the protocol uses TDMA
(Time Division Multiple Access, a channel access
method for shared medium network) technology
to arbitrate and coordinate communications
between devices.

Standardization

3.
Ambient
Intelligence in
Practice
1. Home Security
2. Home Surveillance
3. Energy Monitoring
4. Appliances Control
5. Health Monitoring

Ambient Intelligence in Practice
Home Services

4.
Topologies and
Protocols.
1. Topologies
2. Protocols
3. Sensors
4. Actuators
5. Coordinators

5.
Development
Platforms
1. Ember
2. Contiki

6.
Embedded,
Ubiquitous and
Wearable
Computing
1. Embedded Computing
2. Ubiquitous Computing
3. Wearable Computing

Embedded Computing: What is it?
Digital electronic system as well as other elements;
Application specific, not highly user
programmable;
Digital logic interacts with the physical world.

Embedded Computing: Attributes
Sensing and control;
Real-time operation;
Designed to meet multiple constraints;
Reliable;
Distributed;
Autonomous.

Embedded Computing: Examples
Sensor networks;
Fly-by-wire;
Engine control;
Medical implants;
Space control.

Embedded Computing: Applications
Improved quality of life: health care, homeland security,
transportation, productivity, entertainment, etc;
Military applications: smart soldier, battlefield of the
future, etc;
Because embedded computers are everywhere, large
numbers are practitioners are needed;
Growing field needs new and improved techniques,
architectures, etc;

Wearable Computing: What is it?
•Controlled by the user;
•Has both operational and interactional constancy, i.e. is always on and
always accessible.
A computer that is subsumed into the personal
space of the user
•Is always with the user;
•Into which the user can always enter a command or receive relevant
information, while walking around or doing other activities.
It is a device that:

Wearable Computing: Attributes
Un monopolizing of the user’s attention: User can attend to other
events;
Unrestrictive to the user: Allows interaction while user carries out
normal functions;
Observable by the user: User can identify computational and non-
computational components of their clothing;
Controllable by the user: User can take control at any time;

Wearable Computing: Attributes
Attentive to the environment: Can enhance the
user’s environment and situational awareness;
Communicative to others: Can be used as a
communications medium;
Shares the same physical and situational context as
the user.

Wearable Computing: Military Applications
Onboard physiological/medical sensor suite to
accelerate casualty care;
Netted communications to maximize
robustness and integration of small teams;
Embedded training;
Enhanced situational awareness;
Synchronized firing of weapons from team.

Ubiquitous Computing: What is it?
Interlacing and embedding computers into the environment
and everyday items to streamline and simplify life;
Sensors support and interact with the environment;
Enables anytime, any place data access and manipulation;
Creates a self regulating and quasi-intelligent user interface.

Ubiquitous Computing: Example

Ubiquitous Computing: Challenges
• Elephant in the room: A central network hub necessary for the
coordination of interlaced systems and sensors.
Handling mobility
• Coordination between sensors eliminates unnecessary power
usage (leaving the light on or TV running)
Power supply for embedded sensors
• Where and how to structure interaction between man and
machine
User Interface

Ubiquitous Computing: In the Movies
• “Smart Car”
Knight Rider
• The doors have emotion, and express this when people
used them
The Hitchhiker's Guide to the Galaxy
• Smart Paper
Minority Report

7.
Context
Awareness
1. Ember
2. …

Context Awareness: Definitions
• Several definitions of context in the literature;
• Any information that can be used to characterize a person, a place
or an object;
• It’s the “Who”, “Where”, “When” and “What” and determines the
“Why”.
Context
• Several definitions of context in the literature;
• A system is context-aware if it uses the context information to
provide relevant information/services to the user, when it
relevancy depends on the user actions.
Context-awareness

• Direct Sensor Access.
• Middleware Infrastructure.
• Context Server.
Context acquisition architecture
• Widgets.
• Network Services.
• Blackboard Model.
Context Management

• Physical and virtual Sensors;
• Logic Sensors.
Sensor Infrastructure
• Key-Value Models;
• Markup Scheme Models;
• Graphical Models;
• Object Oriented Models;
• Logic Based Models;
• Ontology Based Models.
Context Modeling

References
1. Wireless Sensor Networks - An Introduction, Wireless Sensor Networks: Application-Centric Design, Yen Kheng
Tan (Ed.), ISBN: 978-953-307-321-7, InTech, Available from: http://www.intechopen.com/books/wireless-sensor-
networks-application-centric-design/wireless-sensornetworks-an-introduction
2. Sensor Networks: Evolution, Opportunities, and Challenges. Chee-Yee Chong, Member IEEE, and Srikanta P.
Kumar, Senior Member, IEEE. Proceedings of the IEEE, Vol. 91, No. 9, August 2003.
3. The Computer for the 21st Century, by Mark Weiser, 1991.
4. 21 Ideas for the 21st Century, 1999. BusinessWeek, August 30, 1999.

Sensor Networks and Ambiente Intelligence

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