Page 715 - Shaping smarter and more sustainable cities - Striving for sustainable development goals

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way that can be read automatically by computers . This enables data from different sources to be
connected and queried. The exponential growth of subject‐predicate‐object expressions creating
links between formerly disparate resources leads to what has been called the Linked Data cloud.
Relentlessly, public and private organizations as well as individuals contribute their data following
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semantic web standards . In 2006, Tim Berners Lee stipulated that interlinking all this data makes
it more useful if 5 simple principles are followed:available, machine‐readable, non‐proprietary data
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formats, RDF data formatandinterlinked to other data by pointing at it . Besides the large, global
vision of linked data, its use in an organization to expose its public information, or even to manage
internal data, brings new possibilities that traditional data management models have been
notoriously bad at handling: It provides a model for naturally accessible and integrated data. In
addition, the graph model it uses offers a level of flexibility that makes it possible to extend and
enrich linked data incrementally, without having to reconsider the entire system: there is no system,
only individual contributions.

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As SSC are a "system of systems", different systems give vast amount of information . By using
model smart city technologies, data amount increase more and more rapidly. This makes it possible
to do many things that previously could not be done: spot business trends, prevent diseases, combat
crime and so on. Managed well, the data can be used to unlock new sources of economic value,
provide fresh insights into science and hold governments to account. However, the traditional data
processing approaches cannot process such a vast amount of information. Big data is developed to
deal this issue and make the city smarter than before. Linked data makes the world wide web into
a global database called the web of data. Developers can query linked data from multiple sources
at once and combine it on the fly, something difficult or impossible to do with traditional data
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management technologies . Many individuals and organizations collect a broad range of different
types of data in order to perform their tasks. The government is particularly significant in this
respect, both because ofthe quantity and centrality of the data it collects, but also because most of
that government data is public data by law, and, therefore, could be made open and made available
for others to use. Linked data plays an important role in the construction and operation of the smart
cities. When the smart city is constructed, open data can provide a large amount of data to assist
the city planners and constructors. The citizens and city managers can make right decisions for city
lives and managements.

Defining standard data layers and tools implemented for open data portal can provide semantic
agreement between heterogeneous data sources. These sources are mainly websites of different
institutions and agencies, which offer data online in unstructured or semi‐structured formats such
as text documents, excel files or XML files. There are very few sources that can provide data
structured in entity‐relationship model. The importance of standard data layers to minimize the
conflict of data generated by several open data portals to publish their data using different models.
Standard data layers for open data portal are divided into four layers as shown in Figure 2.

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31 T.; Bizer, C.; Linked Data: Evolving the Web into a Global Data Space Heath. 2011.
32 Allen, B.P.; Tennis, J.T.; Building metadata‐based navigation using semantic Web standards: the Dublin Core 2003;
Conference Proceedings, 2004. Proceedings of the 2004 Joint ACM/IEEE Conference on. 200
33 Please see: http://linkeddata.org/faq.
34 Turchi, S.; Paganelli, F.; Bianchi, L.; Giuli, D.A lightweight linked data implementation for modeling the Web of Things.
Pervasive Computing and Communications Workshops (PERCOM Workshops), 2014 IEEE International Conference
on 2014, Page(s): 123‐128.
35 David W., Marsha Z. and Luke R. with Michael H.; Linked Data: Structured Data on the Web.

ITU‐T's Technical Reports and Specifications 705