Page 63 - ITU Journal - ICT Discoveries - Volume 1, No. 2, December 2018 - Second special issue on Data for Good

ITU JOURNAL: ICT Discoveries, Vol. 1(2), December 2018

Example Proper- tion, WoT Scripting API [14]. This provides a
Metadata Primary Uses
ties uniform way to write applications for WoT and
allow scripts to run on devices for discovery,
- Interoperability
Preservation - Digital object - Checksum provisioning, and the control of them [16].
metadata management - Preservation
event
- Preservation In literature, approaches to develop languages,
frameworks, software, etc. are also in progress. To
- Interoperability - Copyright status
Rights metada- - License terms support representations of things, a descriptive
ta - Digital object language for devices, IoT Device Description
management - Rights holder Language (IoT-DLL), is presented in [17]. Although
- Sequence
Structural - Navigation it aims for automation and interoperability of
metadata - Place in hierar- smart devices, it is compatible only when the
chy
- Paragraph devices are described in this particular language.
Markup lan- - Navigation - Heading In [18], a Semantic IoT Framework is proposed,
guages - Interoperability which facilitates realizing the changes in data or
- List
metadata, analyzing data, and firing domain-
2. RELATED WORK specific rules or policies. The core part of the
proposed framework is composed of the modules
Many approaches in projects and standardization that perform updating the data changes, activating
activities target interoperable, semantic, the actions, and processing data. However, the
a u t o m a t e d , a n d d y n a m i c I o T e c o s y s t e m s . interoperability issue still has not been solved
Accordingly, works on data models, ontologies, since these procedures occur on the platform level
platforms, frameworks, and software have been so that it is not applicable to data-level processing;
continuously done. Developed by World Wide Web more importantly it is out of the proposed
Consortium (W3C), a semantic sensor network framework. In [19], a tool called SysFlow Workflow
(SSN) [9] is one of the most significant and Engine is presented, which receives a systems
widespread models to describe sensors and IoT- modeling language workflow in an XML metadata
related concepts. W3C SSN ontology provides the interchangeable format to parse and execute
concepts describing connected devices in great workflows. This work provides a way to automate
detail across a wide range of applications. Even the workflows by utilizing metadata, but the
though there exists a number of other semantic proposed tool is yet restricted to some specific
sensor network ontologies, many of them utilize domains, and its shortcoming comes when the
W3C SSN as their basis or underlying model. Hence, users do not have access or their preference in the
W3C SSN currently plays a key role in IoT, WoT proposed tool for their interested application domain.
and SWoT [10]. IoT-Lite [11] is a lightweight
semantic model which is an instantiation of W3C The aforementioned approaches are focused on
SSN ontology. Due to its detailed description, W3C semantically providing common descriptions on
SSN can be considered to be heavy, and IoT-Lite is data and devices in order to support automation
developed to minimize concepts and relationships and interoperability in existing WoT environments
of W3C SNN while providing answers to most end- or their own developed platforms, frameworks,
user queries. There exist ongoing European and infrastructures. However, to truly enable
projects that leverage the W3C SSN ontology as automatic and interoperable interactions among
their starting points for achieving interoperability. devices, devices and systems need to be
For example, Federated Interoperable Semantic empowered by additional information on the basic
Testbeds and Applications (FIESTA) [12] and procedures of how they are allowed to interact
Inter-IoT [13] utilize W3C SSN ontology as their with others. Common understandings of not only
basis and extend it in their own ways. Currently, data and devices but also cooperative decision
W3C is making progress on establishing the Thing logic and action workflows need to be established
Description (TD) repository for common for automation and interoperability. For common
representation for a WoT description. TD provides descriptions on logic, functions, and workflows
the semantic metadata and functional description among devices in systems and services, the
of devices in events, properties, and actions [14], concept of a new metadata type, so-called
[15]. Along with TD, W3C is also working on an procedural metadata is presented in the following
application programming interface (API) specifica- section.

© International Telecommunication Union, 2018 41