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Social Networks

Data Visualization

Interconnect the Dataset
with other Datasets
L
i
n Query Interface
k RDF Query Processor
e SparQL Semantic Semantic
d Endpoint SparQL Analyzer Reasoner
Query
D
a
t RDF Triple RDF
a Storage Convertor

Raw Data
Structure
RDB Data Extractor Extractor Extractor
Structure Semi-Structure Unstructure
Data Data Data

Figure 2 – Overall Standard Data layers for Open Data Portal
The first layer is raw data layer. According to Elmasru and Navathe and Kent, data can be further
classified into three components: structured data, semi‐structured data, and unstructured data.
Structured data are those organized in according to a rigid and pre‐defined criteria such as
respecting various fields (or attributes) of data, delimiting thes cope, domain (possible values) of
data, data type, etc. This is the case, for example, with data involved in tables of relational databases
(RDB) used by most institutions. The structured data extractor is responsible for data extraction of
data stored on the RDB. An important aspect of data publication on the traditional Web is related
to the loss of structure while transforming this data from RDB to open data portals. These data are
converted into current web formats, making them unstructured. Semi‐structured data are given in
a way one cannot always predict all aspects of a given piece of data. Some of its general attributes
can be known and required in advance, others added later depending on circumstances. References
are an example of semi‐structured dataset, containing fairly similar items. The semi‐structured data
extractor is responsible for data extraction of semi‐structured data on the open data portals.
Unstructured data are those for which no scheme isspecified, containing only the content and a
means of presenting it. An example is the text on a HTML page. The unstructured data extractor is
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responsible for data extraction of unstructured data on the open data portals .
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36 Please see: http://linkeddata.org/faq

706 ITU‐T's Technical Reports and Specifications