OpenCube Project: webinar 1 (Sept 8, 2015)

Efthimios Tambouris, University of Macedonia & CERTH, Greece

1st OpenCube Webinar

8 September 2015

The OpenCube Project:Introduction

Statistical Data and Linked Open Data Technologies

The OpenCube Project

Linked Statistical Data Lifecycle

Tools for Linked Statistical Open Government Data

Conclusions

2

Table of Contents


Open (Gov) Data are very important for the EU

A big portion of Open Data concerns statisticse.g. 6875 out of 7682 datasets of the EU Open Data Portal are of statistical nature.

Statistical data is often organized as data cubes, where each cell contains a measure described based on a number of dimensions.

3

Nature of Open Gov Data


Data Cube

OLAP Operations: drill up/down, slicing, dicing, pivot etc.

Data cubes essential for Business Intelligence

4

Dimensions Hierarchy

Measure


Users frequently want to blend & combine statistical data from multiple sources

But, these data usually resides in files and databases (data silos) that are hard to combine

5

Focus


Linked Data has the potential to enable combining and performinganalytics on top of disparate and previously isolated statistical data

The RDF Data Cube Vocabulary has been proposed for modellingmulti-dimensional data as RDF graphs.

However, tools for handling linked data cubes:

are only few and scattered

have not been tested under real-life conditions

6

Linked Data

Potential of using LOD in statistical data analysis unexploited






Conclusions

7

Table of Contents


8

The OpenCube project

OpenCube is a 2-year project funded by the EU within FP7

The project aims to develop and test processes and tools for managing statistical

linked open data.

The results will:

Facilitate data publishers to create linked data cubes from legacy formats

Empower data users to browse, visualise, link, expand and analyse data cubes.

Enable analysis not possible before (merging data cubes at a Web scale)






Conclusions

9

Table of Contents


We propose a lifecycle for statistical LD

The lifecycle is divided into three phases: create, expand and exploit (or consume)

The lifecycle prescribes the steps that raw data cubes* should go through in order to create value.

OpenCube also develops tools to support the whole lifecycle of linked statistical data.


10

E. Tambouris, E. Kalampokis, K. Tarabanis (2015) Processing Linked Open Data Cubes, Electronic GovernmentVolume 9248 of the series Lecture Notes in Computer Science pp 130-143.

* We assume statistical data is organized as data cubes, where each cellcontains a measure described based on a number of dimensions.






Conclusions

11

Table of Contents


Creating components TARQL extension

D2RQ /R2RML-QB extension

JSON-stat

Grafter

Exploiting components OpenCube Browser

OpenCube MapView

R Analysis Chart

Expanding components

12

OpenCube Toolkit

Developed using Information Workbench open source as underlying linked data management platform

License scheme OpenCube components are

provided under open source licenses

Check http://opencube-toolkit.eu

But, commercial solutions are also offered by consortium members


http://opencube-toolkit.eu/

13

Creating data Components


14

Exploiting data: OpenCube browserSummarize observations

across a dimension

(dimension reduction)

Change the axes

of the table

Change the

language

Change the fixed

values

It enables the exploration of an RDF data cube by presenting a two-dimensional slice of the cube as a table.

The slice is created by setting a fixed valuesfor each dimensionthat is not presented in the table.


Visualization of RDF data cubes on a map.

It supports: Markers

Bubble

Choropleth maps

15

Exploiting data: OpenCube MapView


Visualisation of analysis results (charts & tables)

Reuse of analysis results: preserving R output as linked data

16

Exploiting data: Integration with R


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Exploiting data: Other Visualizations

Analytics and ReportingVisualization and Exploration

Stock chart


Enables performing analytics on top of combined data cubes

Steps: 1. Select a data cube

2. Discover cubes on the Web of Linked Data having compatible structure; i.e. cubes with dimensions, measures etc. that can expand the initial cube

3. Create expanded views of the initial cube

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Expanding Statistical Data






Conclusions

19

Table of Contents


Open Statistical data are rapidly increasing due to Open Data policies

Linked Data technologies can provide web-scale linking and analysis of statistical data

OpenCube project develops processes and tools for statistical data management

These can be divided into: Tools for creating linked open statistical data

Tools for expanding open statistical data

Tools for exploiting linked open statistical data

Practical use of the tools follows!!

20

Conclusions


For more information

http://opencube-project.eu

http://opencube-toolkit.eu

Check out our free webinars!!

Project coordinators:

Konstantinos Tarabanis, [email protected]

Themis Tambouris, [email protected]

21

More on OpenCube…

OpenCube consortium



http://opencube-toolkit.eu/

mailto:[email protected]

mailto:[email protected]

Evangelos Kalampokis, University of Macedonia & CERTH, Greece


8 September 2015

The OpenCube Project:the OpenCube OLAP Browser

1st OpenCube Webinar 23

Data Cube

Dimensions Hierarchy

Measure

It is a proof of concept of the linked data analytics vision.

It enables performing OLAP operations on top of integrated views of multiple linked data cubes.

24

The OpenCube OLAP browser


25

Architecture


26

Architecture (Aggregator)

The Aggregator computes

aggregations of cells across

dimensions or hierarchies


27

Architecture (Compatibility Explorer)

Given a cube in the local store,

the Compatibility Explorer

(a) Searches into the Linked

Data Web and identifies

cubes that are compatible to

expand the initial cube and

(b) Establishes typed links

between the local and the

compatible cubes


Binary relations that link two cubes that are compatible to integrate.

Operators that map from these two cubes to a new expanded one.

The framework assumes that a cube can be expanded by increasing the size of one of the sets that define a cube i.e.:

The set of measures

The set of objects of an attribute of a dimension

The set of attributes of a dimension

The set of dimensions

28

Theoretical Framework


29

Architecture (Expander)

The Expander creates a new

expanded cube by merging two

compatible ones.

The Expander implements the

theoretical framework


30

Architecture (OLAP Browser)

The linked data OLAP browser

exploits the others components

of the platform in order to

enable performing OLAP

operation on top of expanded

cubes.

These may include measures,

dimensions, objects, and/or

attributes from multiple cubes

that reside on disparate sources

on the Web.


31

OLAP Browser


An instance of the developed platform have been deployed at the premises of the Flemish government.

Flemish government had already opened up statistics by means of linked data cubes.

11 cubes had been transformed to linked data according to the QB vocabulary and stored in a Virtuoso RDF store.

Using the Aggregator a total of 230 sub-cubes have been created.

250 links have been established from 73 cubes or (sub)cubes to other compatibles (sub)cubes

32

The Flemish Government


The user selects one of the cubes

33

OpenCube Browser


The browser starts with an empty canvas

34

OpenCube Browser


The user can change the language

35

OpenCube Browser


The user can see the dimensions of the cube

36

OpenCube Browser


The user can see the measures of the cube

37

OpenCube Browser


When the user selects at least one measure and one dimension…

38

OpenCube Browser

The geo

dimension has 4

levels


When the user selects a second level in a dimension…

39

OpenCube Browser (Drill-down & roll-up)

2 levels have

been selected


Keep in mind that you can select at most 2 levels

40

OpenCube Browser (Drill-down & roll-up)


41

OpenCube Browser (Selecting more measure & dimensions)

We set a fixed

value in the

other

dimensions

Different colors

for multiple

measures


All this time you see a green message

The user is able to select to expand the cube that sees in the table using data from other cubes

42

OpenCube Browser (Expander)


43

OpenCube Browser (Expander)


44

OpenCube Browser (Expanded cube)

A new measure has

been added in the initial

cube


45

OpenCube Browser (Browsing Multiple Cubes)


The work presented in the paper is partly funded by

46

Acknowledgments


@OpenCubeProject



The OpenCube Toolkit

Tuesday, September 15 at 06:00 PM CEST

http://opencube.enterthemeeting.com/m/KY3XXTKB

PublishMyData for publishing governmental statistical data

Tuesday, September 22 at 06:00 PM CEST

http://opencube.enterthemeeting.com/m/VCAJFCJW

47

Next webinars


http://opencube.enterthemeeting.com/m/KY3XXTKB

http://opencube.enterthemeeting.com/m/VCAJFCJW

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OpenCube Project: webinar 1 (Sept 8, 2015)

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