Page 30 - AeM_October_2021

BUZZWORDS

Web of Things (WoT)

At first glance, the World Wide Web Consortium
(W3C) and the Internet of Things (IoT) are two
different worlds. The consortium is considered
the authority for web standards and ensures that
everyone can find information on the World Wide
Web regardless of their device. Both the
relatively simple web development and the so-
called service composition (mashup) work
relatively smoothly when integrating and offering
different and partly external services such as
road maps, weather data or translation services.
But it is precisely this orchestration of services
that is less trivial on the Internet of Things. IoT A TD provides information about the data and functions
devices offer data and services such as sensor provided, the type of data serialization and the security
values for the temperature or switching a lamp mechanisms used for access control. In addition, there
on and off. Communication works smoothly is other metadata that can be read by machines or hu-
mans. A TD is written in JSON-LD (JavaScript Object
when companies use all devices from a Notation for Linked Data) format. The IoT device can
manufacturer and rely exclusively on its app or provide it directly, or the information is in a repository
ecosystem, but a cross-manufacturer service such as a TD directory.
composition is much more difficult, especially
since security requirements differ from one WoT is a protocol-independent approach and offers a
another. And that exactly the gap the W3C wants uniform mechanism for mapping specific protocols such
to close with the standardization activity for the as MQTT, HTTP, CoAP or Modbus to the abstraction
Web of Things (WoT). elements Properties, Actions and Events. Binding tem-
plates exist for the mapping and the protocol-specific
It is explicitly not about establishing yet another IoT metadata. The optional component WoT-Scripting-API
standard in the form of an additional protocol or data defines an ECMAScript-API, which is based closely on
model, but rather providing tools or so-called technolo- the TD specification and uses the WoT interaction ab-
gy modules to create a uniform level of abstraction for straction. It defines the interface between the behavior
the heterogeneous IoT landscape. implementation and a script based WoT runtime. The
implementation is not limited to scripting environments:
It is deliberately kept simple and offers the following programming language APIs in Java or C / C++ can be
three core elements: derived from the WoT scripting API. In addition, the
Web of Things deals with topics such as discovery and
1. Properties typically map sensor, status, or parame- various aspects of security and privacy.
ter values

In short, the Web of Things offers a new approach to
2. Actions represent functions with input and output cope with the heterogeneity in the IoT environment.
values, for example starting a motor, moving a ro- The Thing Description creates an understanding of dif-
bot arm, or taking a photo
ferent IoT systems and can be used for the composition
3. Events typically map alarm signals or data streams of services. Thanks to JSON-LD, the Thing Description
can be annotated with additional semantics, for exam-
The so-called Thing Description (TD), which maps ple, from SAREF, schema.org and/or ECLASS. This
properties, actions, and events, plays a central role. addition improves interoperability and (machine) under-
Like index.html on a website, it provides the entry point standing, among other things, regarding the intention
of an IoT device or a service. and the context of the properties, actions, and events. ◊

By MediaBUZZ

30 October 2021: IoT in Marketing