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and possible future extensions.
2 WOT FOR SMART
APPLIANCES
2.1 Internet Protocols and Home
Automation Standards
The internet has been a great success over two
decades with ubiquitous use of the network by bil-
lions of people. The internet paradigm has been
very successful with heterogeneous networks, and the
www model of uniform resource locators (URLs),
the hypertext transfer protocol (HTTP) and hypertext
markup language (HTML). This has resulted in IT
architects, communication experts and others to in-
novate and add new protocols and uses for internet
technology. Another internet advance has been the
internet of things where the embedded devices, also
named, smart objects, are universally becoming IP-
enabled and an integral part of the internet. Examples
of IP-enabled embedded devices are mobile devices,
personal health assistance devices, home and indus-
trial automation, smart metering etc (Guinard, 2010;
Kamilaris et al., 2011).
There are many competing home automation stan-
dards such as the popular X10 in the residential
market since 1978 (www.x10.com), ZigBee standard
based on IEEE 802.15.4, and KNX, the European
standard. Currently, monitoring and controlling em-
bedded devices are predominantly done using ser-
vices built on internet technology. Internet of things
is a powerful paradigm which has combined the
internet-enabled embedded devices and web services
technology. Till recently, the complexity of commu-
nication standards, protocols and services meant that
internet enabling happened only with the most pow-
erful embedded devices.
The first global low-power radio standard was re-
leased by IEEE, which was the 802.15.4 low-power
wireless personal area network (WPAN) standard in
2003. A new paradigm was required to enable low-
power wireless devices with limited processing capa-
bilities to participate in the Internet of Things (Hui
and Culler, 2008; Shelby and Bormann, 2010). The
6LoWPAN standard makes this latest Internet proto-
col (IPv6) available to even the most minimal embed-
ded devices over low-rate wireless networks (Design,
2011), and is well suited for embedding into home
appliances.
Since typical households have cable Ethernet con-
nections and Wi-Fi as the backbone network, exten-
sion via 6LoWPAN is possible without laying addi-
tional cables. Although deployment costs for both
ZigBee and 6LoWPAN (IPv6) are low, ZigBee being
a proprietary solution requires its own infrastructure
as opposed to using LANs for 6LoWPAN/IPv6 [24].
Seamless integration to the internet is the attractive
feature available with IPv6 over the other standards.
IPv6 connectivity of smart appliances integrates these
appliances to the internet network layer. Web servers
running on the appliances are required to achieve web
integration (application layer). The concept of Re-
source is a first class object in the REST (represen-
tational state transfer) style and every resource must
understand the core operations (Richardson and Ruby,
2007). A smart appliance resource is accessed in a
web-oriented manner using a lightweight REST ar-
chitectural style. Any smart appliance resource is
bound to a Uniform Resource Identifier (URI), which
identifies the resource involved in an interaction be-
tween entities. It uses HTTP 1.1 as a true applica-
tion protocol and its operations, GET, PUT, POST,
DELETE. Each resource implements a set of these
well-defined operations. Applications using web-
enabled appliances can be developed using web lan-
guages such as Javascript, PHP, JSON (javascript ob-
ject notation) and toolkits such as JQuery. Android
and IPhone OS 4.0 run IPv6.
It follows from the discussion in this section that
6LoWPAN /IPv6 is suitable for smart home automa-
tion applications.
2.2 IoT, WoT and WoT Framework
The web is a very effective, user-centric, scalable, dis-
tributed platform with underlying technologies such
as TCP/IP, HTTP, HTML/XML, JSON etc. This suc-
cess has now been extended to incorporating real-
world objects into WWW using web technologies,
and this is called the Web of Things (WoT), as de-
scribed next.
The Internet of things (IoT) (Papadimitriou, 2009)
is about principles and technologies that enable the
internet to get into the real-world of physical objects.
IoT gives every device an IP address and lets it plug
into the internet. In IoT, everyday devices and objects
(objects that contain an embedded device) are con-
nected by integrating these into the web. Examples
of smart devices are sensor network, household appli-
ances etc. Web of Things (WoT) is an extension to
IoT (Zeng et al., 2011) and is about reusing the web
standards and building on the success of web 2.0.
Well-established web standards and blueprints
such as HTTP, REST, URI etc are used in WoT. This
ensures ease of development with existing web frame-
PECCS 2012 - International Conference on Pervasive and Embedded Computing and Communication Systems
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