Web of Things (WoT) describes a set of standards by the
World Wide Web Consortium
The World Wide Web Consortium (W3C) is the main international standards organization for the World Wide Web. Founded in 1994 and led by Tim Berners-Lee, the consortium is made up of member organizations that maintain full-time staff working to ...
(W3C) for the interoperability of different
Internet of things
The Internet of things (IoT) describes physical objects (or groups of such objects) with sensors, processing ability, software and other technologies that connect and exchange data with other devices and systems over the Internet or other comm ...
(IoT) platforms and application domains.
Building blocks
The WoT building blocks provide a way to implement systems that conform with the WoT
architecture
Architecture is the art and technique of designing and building, as distinguished from the skills associated with construction. It is both the process and the product of sketching, conceiving, planning, designing, and constructing building ...
. Each of these blocks is described below in this section.
Thing Description (TD)
The key component of the WoT building blocks is the
WoT Thing Description. A Thing Description describes a virtual or a physical device (Thing). It defines an information model of a Thing based on semantic vocabulary and a serialization based on
JSON
JSON (JavaScript Object Notation, pronounced ; also ) is an open standard file format and data interchange format that uses human-readable text to store and transmit data objects consisting of attribute–value pairs and arrays (or other ser ...
. TD can be considered as the main entry point for a Thing, like an
index.html page for a website. TDs foster
interoperability
Interoperability is a characteristic of a product or system to work with other products or systems. While the term was initially defined for information technology or systems engineering services to allow for information exchange, a broader defi ...
by providing both human and machine-readable (and understandable)
metadata
Metadata is "data that provides information about other data", but not the content of the data, such as the text of a message or the image itself. There are many distinct types of metadata, including:
* Descriptive metadata – the descriptive ...
about a Thing, such as a title, ID, descriptions, etc. A Thing Description also describes all available actions, events, and properties of a Thing, as well as all available security mechanisms to access them. TD is highly flexible in order to guarantee interoperability. In addition to the standard functionality, it defines a mechanism to extend the functionality (through the Context Extension Framework).
Binding Templates
IoT
The Internet of things (IoT) describes physical objects (or groups of such objects) with sensors, processing ability, software and other technologies that connect and exchange data with other devices and systems over the Internet or other com ...
uses a large variety of protocols to interact with Things since there does not exist a single protocol, which is suitable for any case. So, one of the main challenges for the Web of Things is to handle the variety of protocols and interaction mechanisms. This problem is tackled through the Binding Templates. WoT Binding Templates provide a collection of communication metadata blueprints to support various IoT solutions. A Binding Template is created only once and then can be reused in any Thing Description.
Scripting API
The WoT Scripting
API
An application programming interface (API) is a way for two or more computer programs to communicate with each other. It is a type of software Interface (computing), interface, offering a service to other pieces of software. A document or standa ...
is an optional building block of Web of Things. It eases IoT application development by providing an
ECMAScript
ECMAScript (; ES) is a JavaScript standard intended to ensure the interoperability of web pages across different browsers. It is standardized by Ecma International in the documenECMA-262
ECMAScript is commonly used for client-side scripting o ...
-based application API in a similar manner to how web browsers provide an API for web applications. By having a universal application
runtime system
In computer programming, a runtime system or runtime environment is a sub-system that exists both in the computer where a program is created, as well as in the computers where the program is intended to be run. The name comes from the compile t ...
, Scripting API solves the problem of
heterogeneity
Homogeneity and heterogeneity are concepts often used in the sciences and statistics relating to the uniformity of a substance or organism. A material or image that is homogeneous is uniform in composition or character (i.e. color, shape, siz ...
of IoT systems. It also enables creating reusable scripts to implement the device logic, which significantly improves the portability of the application modules.
The current reference implementation of the WoT scripting API is an open-source project calle
''node-wot'' which is developed by th
''Eclipse Thingweb''project.
Security and Privacy Guidelines
In WoT architecture, security is relevant to all aspects of the architecture. Specification of each WoT building block contains several considerations regarding security and privacy of that particular block. Security is supported by certain explicit features, such as public metadata in Thing Descriptions and separation of concerns in the design of Scripting API. In addition, there is also a specification called
WoT Security and Privacy Guidelines', providing guidance on a variety of security and privacy related concerns.
History
Connecting objects to the Web arguably started around the year 2000. In 2002, a peer-reviewed paper presented the Cooltown project.
This project explored the use of URLs to address and HTTP interact with physical objects such as public screens or printers.
Following this early work, the growing interest in and implementation of the
Internet of things
The Internet of things (IoT) describes physical objects (or groups of such objects) with sensors, processing ability, software and other technologies that connect and exchange data with other devices and systems over the Internet or other comm ...
started to raise some questions about the application layer of the IoT.
[
] While most of the work in the IoT space focused on network protocols, there was a need to think about the convergence of data from IoT devices. In particular, rather than looking at "one device, one app", researchers and practitioners started envisioning the IoT as a system where data from various devices could be consumed by Web applications to create innovative use cases.
The idea of the Web as an application layer for the IoT started to emerge in 2007. Several researchers started working in parallel on these concepts. Amongst them,
Dominique Guinard
Dominique "Dom" Guinard is the CTO of EVRYTHNG. He is a technologist, entrepreneur and developer with a career dedicated to building the Internet of Things both in the cloud and on embedded Things. He is particularly known for his early contribu ...
and
Vlad Trifa
Vlad Trifa is a computer scientist, researcher and Chief Product Officer aAmbrosuswho played a key role in defining and implementing the application layer of the Internet of Things. He is particularly known for his early contributions to the Web o ...
started the Web of Things online community and published the first WoT manifesto, advocating the use of Web standards (REST, Lightweight semantics, etc.) to build the application layer of the IoT. The manifesto was published together with an implementation on the Sun SPOT platform. At the same time,
Dave Raggett
Dave Raggett is an English computer specialist who has played a major role in implementing the World Wide Web since 1992.
He has been a W3C Fellow at the World Wide Web Consortium since 1995 and worked on many of the key web protocols, including ...
from
W3C
The World Wide Web Consortium (W3C) is the main international standards organization for the World Wide Web. Founded in 1994 and led by Tim Berners-Lee, the consortium is made up of member organizations that maintain full-time staff working to ...
started talking about a Web of Things at various W3C and IoT events. Erik Wilde published "Putting Things to REST", a self-published concept paper looking at utilizing REST to sense and control physical objects.
Early mentions of the Web of Things as a term also appeared in a paper by Vlad Stirbu et al.
From 2007 onwards, Trifa, Guinard, Wilde and other researchers tried publishing their ideas and concepts at peer-reviewed conferences, but their papers got rejected by the Wireless Sensor Networks research community on the basis that Internet and Web protocols were too verbose and limited in the context of real-world devices,
where optimization of memory and computation usage, wireless bandwidth, or very short duty cycles were essential.
However, a number of researchers in the WSN community started considering these ideas more seriously. Early 2009, several respected WSN researchers such as David Culler, Jonathan Hui, Adam Dunkels and Yazar Dogan evaluated the use of Internet and Web protocols for low-power sensor nodes and showed the feasibility of the approach.
Following this, Guinard and Trifa presented their end-to-end implementation of the concepts and presented it in a peer-reviewed publication accepted at the World Wide Web conference in 2009.
[
] Building on this implementation and uniting efforts, a RESTful architecture for things was proposed in 2010 by Guinard, Trifa and Wilde.
Noticing a growing industrial and academic interest in connecting things to the Web, Guinard, Trifa and Wilde ran the first International Workshop on the Web of Things,
WoT 2010 which has been running yearly since. These workshops have become the first forum where a growing community of researchers and practitioners could discuss the latest findings and ideas in the Web of Things.
In 2011, two of the first PhD theses on the Web of Things were presented at ETH Zurich: Building Blocks for a Participatory Web of Things: Devices, Infrastructures, and Programming Frameworks from Vlad Trifa
and A Web of Things Application Architecture – Integrating the Real-World into the Web from Dominique Guinard.
Building on this work, Simon Mayer emphasized the importance of REST's uniform interface, and in particular the
HATEOAS
Hypermedia as the Engine of Application State (HATEOAS) is a constraint of the REST application architecture that distinguishes it from other network application architectures.
With HATEOAS, a client interacts with a network application whose app ...
principle, in his PhD thesis.
In 2014, the W3C showed an increased interest in the Web of Things and organized the W3C Workshop on the Web of Things, under the lead of Dave Raggett together with
Siemens
Siemens AG ( ) is a German multinational conglomerate corporation and the largest industrial manufacturing company in Europe headquartered in Munich with branch offices abroad.
The principal divisions of the corporation are ''Industry'', '' ...
and the COMPOSE European project. This workshop leads to the creation of the Web of Things Interest Group at
W3C
The World Wide Web Consortium (W3C) is the main international standards organization for the World Wide Web. Founded in 1994 and led by Tim Berners-Lee, the consortium is made up of member organizations that maintain full-time staff working to ...
and the submission of the Web Thing Model.
The same year, Siemens announced the creation of a research group dedicated to the Web of Things. In October 2014, Google also announced its interest in these ideas by launching the Physical Web GitHub project.
The Web of Things Interest Group identified the required set of standards needed for the Web of Things in February 2017
.
[
] The Working Group has started working on 4 deliverables called WoT Architecture,
[
]
WoT Thing Description,
[
]
WoT Scripting API
[
] and
WoT Binding Templates.
[
]
See also
*
Internet of Things (IoT)
*
Smart device
A smart device is an electronic device, generally connected to other devices or networks via different wireless protocols (such as Bluetooth, Zigbee, near-field communication, Wi-Fi, LiFi, or 5G) that can operate to some extent interactively and ...
*
Connected Device
*
Home automation devices
*
Smart grid
A smart grid is an electrical grid which includes a variety of operation and energy measures including:
*Advanced metering infrastructure (of which smart meters are a generic name for any utility side device even if it is more capable e.g. a f ...
Further reading
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External links
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References
{{Ambient intelligence
Cloud standards
Web 2.0 neologisms
World Wide Web
Internet of things
World Wide Web Consortium