We often present our work in tutorials that take place at international conferences. Some recent
tutorials are the following:
- ISWC 2022 tutorial: Artificial Intelligence Techniques for
Earth Observation Data (AI4EO).
Tutorial at the 21st International Semantic Web Conference 2022
October 23, 2022
In the last few years, there has been a lot of research in applying Artificial Intelligence
techniques to Earth observation data. The subareas of Artificial Intelligence that contributed
the most to the science of satellite data. are Deep Learning and Semantic Technologies
(Ontologies and Linked Data). This tutorial will survey the latest state of the art in this
area. It will start by explaining what satellite data is and why satellite data is a
paradigmatic case of big spatiotemporal data amenable to Artificial Intelligence techniques.
Examples of big satellite data, information and knowledge will be given for the case of the
Copernicus program of the European Union. We will teach the tutorial participants how to “break
satellite data silos open” by publishing the metadata of satellite datasets as microformats to
enable their discovery by modern search engines through services like Dataset Search of Google,
how to extract important geospatial information from satellite datasets using deep learning
technologies, how to interlink this information with other relevant information available on the
Web, and how to make this wealth of data and information freely available on the Web to enable
the easy development of geospatial applications. We will present a complete pipeline that starts
with satellite datasets in various formats that are made freely available in the archives of
space agencies and ends with the deployment of an interactive visual application that uses
satellite data utilizing linked data technologies. We will also present a query answering system
over geospatial knowledge graphs, that allows non-experts to access linked geospatial data using
natural language. The tutorial will give an in-depth coverage of the relevant techniques,
systems and some applications developed by the presenters in the last 12 years in the context of
1 ERC grant (BigEarth), 12 European projects (TELEIOS, LEO, Melodies, Optique, BigDataEurope,
Copernicus App Lab, WDAQUA, ExtremeEarth, AI4Copernicus and DeepCube), 1 ESA project
(Prod-Trees), 3 projects funded by the German government (BIFOLD, TreeSatAI, IDEAL-VGI) and 2
projects funded by the Greek government (SCARE and GeoQA). The two teams presenting the tutorial
(from the National and Kapodistrian University of Athens and the Technische Universität Berlin)
come from different disciplines (Computer Science and Satellite Remote Sensing) and will offer
an interdisciplinary presentation of the relevant theoretical and practical issues.
Tutorial Overview
This is a full-day tutorial. A brief overview is provided below:
Part 1: Introduction. Satellite remote sensing and satellite data. Copernicus data
as a paradigmatic case of big spatiotemporal data. A data science pipeline for big linked EO
data.
Part 2: The data science pipeline. Ingestion, processing, cataloguing and
archiving EO data. Knowledge discovery from satellite images. RDF and SPARQL extensions for
spatiotemporal data and how to use them to represent information and knowledge extracting from
satellite images. Spatiotemporal RDF stores. Interlinking geospatial and temporal RDF data.
Question answering over geospatial knowledge graphs. Searching, browsing, exploring and
visualizing inked spatiotemporal data.
Part 3: Hands-on session. Transformation of data from their original format into
the RDF model. Store and query the resulting data using Strabon. Interlinking the
resulting data to other interesting data sources (e.g., OpenStreetMap, agricultural data) using
JedAI-spatial. Query over the YAGO2geo knowledge graph using GeoQA. Visualization of the data
sources and developing a demo application using Sextant.
Tutorial Programme
(All times are CET)
10:00 - 10:15: Introduction
10:15 - 10:45: Discovering Earth Observation data
10:45 - 11:15: Deep Earth Query: Information Discovery from Big Earth Observation Data Archives
11:15 - 11:30: Coffee break
11:30 - 12:00: RDF and SPARQL extensions for geospatial data
12:00 - 12:30: Geospatial RDF stores
12:30 - 13:30: Lunch
13:30 - 14:00: Transformation of geospatial data
14:00 - 14:30: Interlinking geospatial RDF data
14:30 - 15:00: Geospatial knowledge graphs
15:00 - 15:15: Coffee break
15:15 - 15:45: Question answering over geospatial knowledge graphs
15:45 - 16:15: Searching, browsing, exploring and visualizing linked geospatial data
16:15 - 17:00: Hands on: Transformation, store, query, visualize
17:00 - 17:30: Hands on: Interlink, Question Answering
17:30 - 17:45: Open problems
Tutorial material
The tutorial presentation is available as PDF here.
Big linked
geospatial data tools covered in the tutorial.
Presenters
Manolis
Koubarakis is a Professor and Director of Graduate Studies in the Dept. of Informatics
and
Telecommunications, National and Kapodistrian University of Athens. He leads the Artificial Intelligence
team. He holds a Ph.D. in Computer Science, from the National Technical University
of Athens, an M.Sc. in Computer Science, from the University of Toronto, and a diploma (B.Sc.)
in
Mathematics, from the University of Crete. He is a Fellow of EurAI (European Association for
Artificial
Intelligence) since 2015 and President of the Hellenic Association for Artificial Intelligence.
He is a
member of the Advisory Board that implements the Hellenic National Strategy for Artificial
Intelligence.
He has published more than 200 papers that have been widely cited (7281 citations and h-index 44
in
Google Scholar) in the areas of Artificial Intelligence (especially Knowledge Representation),
Databases, Semantic Web and Linked Geospatial Data (especially Earth observation data). His
research has
been financially supported with a total amount exceeding 8 million Euros by the European
Commission, the
Hellenic Foundation for Research and Innovation, the Greek General Secretariat for Research and
Technology, the European Space Agency and industry. Manolis currently participates in H2020
project
AI4Copernicus (2021-2023, as Technical Manager of this project which brings Copernicus data the
the
AI4EU platform) and DeepCube (2021-2023, where he leads the work on Semantic Data Cubes).
Affiliation: National and Kapodistrian University of Athens
Email: koubarak[at]di.uoa.gr
Begüm Demir is a
Professor and Chair of the Remote Sensing Image Analysis (RSiM) group at the Faculty of
Electrical
Engineering and Computer Science, Technische Universitat Berlin (TU Berlin), Germany. Before
joining TU
Berlin, she was an Assistant Professor at the Department of Computer Science and Information
Engineering, University of Trento, Italy, from 2013 to 2017 while in 2017 she became an
Associate
Professor at the same department. Her main research interests include machine learning and big
data
management with applications to remote sensing image analysis. She was a recipient of an ERC
Starting
Grant with the project “BigEarth-Accurate and Scalable Processing of Big Data in Earth
Observation’ in
2017 and the IEEE Geoscience and Remote Sensing Society Early Career Award in 2018. She has been
a
senior member of IEEE since 2016.
Affiliation: Technische Universität Berlin
Email: demir[at]tu-berlin.de
Dimitris
Bilidas is
a postdoctoral researcher at the Management of Data, Information and Knowledge group, in the
Dept. of
Informatics and Telecommunications, National and Kapodistrian University of Athens. Dr. Bilidas
obtained
a B.Sc. from Department of Informatics, University of Piraeus and a M.Sc. in Advanced
Information
Systems from Department of Informatics and Telecommunications in National and Kapodistrian
University of
Athens, and a PhD under the supervision of Professor Manolis Koubarakis, in the area of query
languages
for the Semantic Web and Distributed Query Processing. Mr. Bilidas has extensive research
experience in
several Greek and European research projects (Optique, Copernicus App Lab, Indigo, Xenios). The
topic of
his PhD is mostly associated with work carried out in the Optique project, concerning Query
Optimization
techniques for Ontology-based Data Access (OBDA), including federated and parallel execution of
OBDA
produced queries.
Affiliation: National and Kapodistrian University of Athens
Email: d.bilidas[at]di.uoa.gr
Theofilos Ioannidis is a software engineer and database administrator at Bank of Greece for the
Electronic Secondary Market of Greek Government Bonds. He has also designed and developed
information
systems for the textile industry and software for Clearing and Settlement Houses for the banking
sector
of several European countries. He is a Research Associate at the Dept. of Informatics and
Telecommunications, National and Kapodistrian University of Athens, and a PhD candidate under
the
supervision of Prof. Koubarakis. He holds a Diploma in Electrical Engineering from the Aristotle
University of Thessaloniki and a Master of Science in Information Systems Engineering from UMIST
at
Manchester, UK. He focuses on semantic big geospatial data technologies and benchmarking in the
same
research area.
Affiliation: National and Kapodistrian University of Athens
Email: tioannid[at]di.uoa.gr
Despina-Athanasia Pantazi is a Research Associate in the Dept. of Informatics and
Telecommunications,
National and Kapodistrian University of Athens, and a PhD candidate under the supervision of
Prof.
Koubarakis. She holds a B.Sc. and M.Sc. from the Department of Informatics and
Telecommunications of the
National and Kapodistrian University of Athens. Her research interests focus in the areas of
Artificial
Intelligence and Semantic Web. As part of her M.Sc. Despina has developed an extension of
schema.org for
annotating satellite datasets.
Affiliation: National and Kapodistrian University of Athens
Email: dpantazi[at]di.uoa.gr
George Papadakis is an internal auditor of information systems and a Research Associate at the
Dept. of
Informatics and Telecommunications, National and Kapodistrian University of Athens. He has also
worked
at the NCSR "Demokritos", the Ιnstitute of Communication and Computer Systems, the L3S Research
Center
and the "Athena" Research Center. He holds a PhD in Computer Science from the University of
Hanover and
a Diploma in Computer Engineering from the National Technical University of Athens. He focuses
on web
data mining and he is the main developer of the tool JedAI, which constitutes a library of
state-of-the-art algorithms for Data Integration.
Affiliation: National and Kapodistrian University of Athens
Email: gpapadis[at]di.uoa.gr
Dharmen Punjani is a Research Associate in the Dept. of Informatics and Telecommunications,
National and
Kapodistrian University of Athens, and a PhD candidate under the supervision of Prof.
Koubarakis. He
holds an M.Tech in Computer Engineering from Sardar Vallabhbhai National Institute of
Technology, Surat
and a B.E. in Computer Engineering from Saradar Patel University, New V.V.Nagar in India. His
research
interests focus on Question Answering, Natural Language Processing, Semantic Web and Machine
Learning.
He has developed GeoQA, the first template-based question answering engine over linked
geospatial data.
Affiliation: National and Kapodistrian University of Athens
Email: dpunjani[at]di.uoa.gr
George
Stamoulis is a Research Associate in the Dept. of Informatics and Telecommunications,
National and Kapodistrian University of Athens, and a PhD candidate under the supervision of
Prof. Koubarakis. He holds a Bsc. and Msc. from the Department of Informatics and
Telecommunications of the National and Kapodistrian University of Athens. His research interests
focus in the areas of Semantic Web, Data Visualization and Integration and User Interfaces.
Affiliation: National and Kapodistrian University of Athens
Email: gstam[at]di.uoa.gr
Eleni Tsalapati is a Marie-Curie fellow at the Management of Data, Information and Knowledge
(Madgik)
group, at the Dept. of Informatics and Telecommunications, National and Kapodistrian University
of
Athens. Eleni obtained a 5-year B.Sc. from the School of Applied Mathematics and Physical
Sciences,
National Technical University of Athens, a M.Sc. in Informatics (with specialization in
Knowledge
Representation and Reasoning) from the University of Edinburgh, and a PhD in the area of Query
Answering
in Description Logics, from the National Technical University of Athens. She brings 10 years’
research
experience in several Greek (GeoQA), European research projects (e.g., AI4Copernicus, Linked
Heritage,
AthenaPlus) and EPSRC projects (RESILIENCE, AI2M). Before joining Madgik, she was for two years
Research
Associate at the University of Loughborough, where she applied semantic technologies for the
automotive
industry and manufacturing. Her current research interests lie in the field of efficient
question
answering over dynamic structured data.
Affiliation: National and Kapodistrian University of Athens
Email: etsalapati[at]di.uoa.gr
- ISWC 2020
tutorial: A Data Science Pipeline for Big Linked
Earth Observation Data.
Tutorial at the 19th International Semantic Web Conference 2020
November 1, 2020 at 9:00 - 16:00 CET (Virtual)
The research areas of Remote Sensing, Big Data, Linked Data, Ontologies, Spatiotemporal Data and
Deep Learning are very crucial for Data Science for satellite data. The tutorial will start by
explaining what satellite data is and why satellite data is a paradigmatic case of big
spatiotemporal data giving rise to all relevant challenges, the so-called 5 Vs: volume,
velocity, variety, veracity and value. Examples of big satellite data, information and knowledge
will be given for the case of the Copernicus programme of the European Union. We will teach the
tutorial participants how to “break satellite data silos open” by publishing the metadata of
satellite datasets as microformats to enable their discovery by modern search engines through
services like Dataset Search of Google, how to extract important geospatial information from
satellite datasets using deep learning technologies, how to interlink this information with
other relevant information available on the Web, and how to make this wealth of data and
information freely available on the Web to enable the easy development of geospatial
applications. We will present a complete data science pipeline that starts with satellite
datasets in various formats that are made freely available in the archives of space agencies,
and ends with the deployment of an interactive visual application that uses satellite data
utilizing linked data technologies. We will also present a query answering system over
geospatial knowledge graphs, that allows non-experts to access linked geospatial data using
natural language. The tutorial will give an in-depth coverage of the relevant techniques,
systems and some applications developed by the presenters in the last 10 years in the context of
8 European projects (TELEIOS, LEO, Melodies, Optique, Big Data Europe, Copernicus App Lab,
WDAQUA, ExtremeEarth), 1 ESA project (Prod-Trees) and 2 projects funded by the Greek government
(SCARE and GeoQA). The team presenting the tutorial (National and Kapodistrian University of
Athens)
will
offer an interdisciplinary presentation of the relevant theoretical and practical issues. The
University of Athens currently leads one of the most important European research projects in the
research areas relevant to this tutorial, the ExtremeEarth project.
Tutorial Overview
This is a full-day tutorial. A brief overview is provided below:
Part 1: Introduction. Satellite remote sensing and satellite data. Copernicus data
as a paradigmatic case of big spatiotemporal data. A data science pipeline for big linked EO
data
Part 2: The data science pipeline. Ingestion, processing, cataloguing and
archiving EO data. Knowledge discovery from satellite images. RDF and SPARQL extensions for
spatiotemporal data and how to use them to represent information and knowledge extracting from
satellite images. Spatiotemporal RDF stores. Interlinking geospatial and temporal RDF data.
Question answering over geospatial knowledge graphs. Searching, browsing, exploring and
visualizing inked spatiotemporal data.
Tutorial Programme
(All times are CET)
09:00 - 09:30: Introduction: The Data Science Pipeline
09:30 - 09:45: Discovering Earth Observation data
09:45 - 10:15: Knowledge discovery from Earth Observation data
10:15 - 10:30: Coffee break
10:30 - 11:00: RDF and SPARQL extensions for geospatial and temporal data
11:00 - 11:30: Transforming geospatial data into RDF
11:30 - 12:00: Interlinking geospatial RDF data
12:00 - 12:30: Evaluating geospatial RDF stores using the benchmark Geographica
12:30 - 13:30: Lunch
13:30 - 14:00: Geospatial ontology-based data access
14:00 - 14:30: The knowledge graph YAGO2geo
14:30 - 15:00: Question answering over geospatial Knowledge Graphs
15:00 - 15:15: Coffee break
15:15 - 15:45: Visualizing linked geospatial and temporal data
15:45 - 16:00: Conclusions
Tutorial material
The tutorial presentation is available as PDF here.
References
- Manolis Koubarakis, Konstantina Bereta, George Papadakis, Dimitrianos Savva and George
Stamoulis. Big, Linked Geospatial Data and Its Applications in Earth
Observation. IEEE Internet Computing July/August (2017), 87–91.
- Manolis Koubarakis, Kostis Kyzirakos, Charalampos Nikolaou, George Garbis, Konstantina
Bereta, Roi Doganinad Stella Giannakopoulou, Panayiotis Smeros, Dimitrianos Savva,
George Stamoulis, Giannis Vlachopoulos, Stefan Manegold, Charalampos Kontoes,
Themistocles Herekakis, Ioannis Papoutsis and Dimitrios Michail. Managing Big,
Linked, and Open Earth-Observation Data: Using the TELEIOS/LEO software stack. IEEE
Geoscience and Remote Sensing Magazine 4, 3 (2016), 23–37.
- Ying Zhang, Martin L. Kersten and Stefan Manegold. SciQL: array data processing
inside an RDBMS. SIGMOD Conference 2013: 1049-1052
- Milena Ivanova, Martin L. Kersten, Stefan Manegold and Yagiz Kargin. Data Vaults:
Database Technology for Scientific File Repositories. Computing in Science and
Engineering 15(3): 32-42 (2013)
Presenters
Manolis
Koubarakis is a Professor in the Dept. of Informatics and Telecommunications, National
and Kapodistrian University of Athens. He previously held positions at the Dept. of Electronic
and Computer Engineering, Technical University of Crete (Assistant and Associate Professor), the
Dept. of Informatics, University of Athens (Visiting Researcher), the Dept. of Computation,
UMIST (now University of Manchester) (Lecturer) and the Dept. of Computing, Imperial College,
London (Research Associate). He has taught undergraduate and graduate courses since 1995. He has
published more than 200 papers that have been widely cited in the areas of Artificial
Intelligence (especially Knowledge Representation), Databases, Semantic Web and Linked Data
(5864 citations in Google Scholar). In 2015, he was elected Fellow of the European Association
of Artificial Intelligence (EurAI). He has served in the program committee of various
international conferences and workshops, and he has organized various international events. With
his research group, he has presented tutorials in 8 international conferences. He has attracted
more than 6M Euros in funding from the European Commission, the Greek General Secretariat from
Research and Technology, the European Space Agency and industry sources. He is the co-ordinator
of the H2020 project ExtremeEarth (2019-2021) which develops distributed deep learning and big
linked geospatial data technologies for satellite data and apply these two technologies in two
application scenarios from the Food Security and Polar Operations domains.
Affiliation: National and Kapodistrian University of Athens
Email: koubarak[at]di.uoa.gr
Claudia Paris is Assistant Professor at the Department of Information Engineering and Computer
Science of the University of Trento, Italy. She received the “Laurea” (B.S.), the “Laurea
Specialistica” (M.S.) (summa cum laude) degrees in Telecommunication Engineering and the Ph.D.
in Information and Communication Technology from the University of Trento, Italy, in 2010, 2012,
2016, respectively. She accomplished the Honors Master Program in Research within the Master
Degree in Telecommunication Engineering in 2012. Since 2014 she is a teaching assistant at the
Department of Information Engineering and Computer Science of the University of Trento, Italy.
In 2014 she was a visiting PhD student at the Rochester Institute of Technology (RIT),
Rochester, New York State, USA, working on the fusion of airborne and terrestrial LiDAR data. In
2016 she was a visiting Post-Doc at the Instituto Superior Técnico, Lisbon, Portugal, working on
the superresolution of multiresolution multispectral remote sensing images. Her main research
includes image processing and machine learning with applications to remote sensing image
analysis. She conducts research on remote sensing single date and time series image
classification, land cover map update and fusion of multisource remote sensing data for the
estimation of biophysical parameters. She conducts research on these topics within the
frameworks of national and international projects. Dr. Paris is a Scientific Committee Member of
the 2020 IEEE International Geoscience and Remote Sensing Symposium (IGARSS 2020) and a Member
of the Programme Committee of the SPIE International Symposium on Remote Sensing for the 2019
and 2020. She is a reviewer for many international journals, among them the IEEE Transactions on
Geoscience and Remote Sensing, IEEE Journal of selected Topics in Applied Earth Observations,
IEEE Geoscience and Remote Sensing Magazine and Remote Sensing and IEEE Geoscience and Remote
Sensing Letters. Dr. Paris won the very prestigious Symposium Prize Paper Award (SPPA) at the
2016 International Symposium on Geoscience and Remote Sensing (Beijing, China, 2016) and at the
2017 International Symposium on Geoscience and Remote Sensing (Fort Worth, Texas, USA, 2017).
Affiliation: University of Trento
Email: claudia.paris[at]unitn.it
George Papadakis is an internal auditor of information systems and a Research Associate at the
Dept. of Informatics and Telecommunications, National and Kapodistrian University of Athens. He
has also worked at the NCSR "Demokritos", the Ιnstitute of Communication and Computer Systems,
the L3S Research Center and the "Athena" Research Center. He holds a PhD in Computer Science
from the University of Hanover and a Diploma in Computer Engineering from the National Technical
University of Athens. He focuses on web data mining and he is the main developer of the tool
JedAI, which constitutes a library of state-of-the-art algorithms for Data Integration.
Affiliation: National and Kapodistrian University of Athens
Email: gpapadis[at]di.uoa.gr
Konstantina Bereta is a Research Associate in the Dept. of Informatics
and Telecommunications, National and Kapodistrian University of Athens. She holds a BSc. and
MSc. from the same departmentment and a PhD under the supervision of Prof. Manolis Koubarakis on
Ontology Based Data Access systems. She has worked as a scientific programmer and research
associate in several EU FP7 projects. Her research interests focus in the areas of
spatiotemporal databases, Semantic Web and Cloud Computing.
Affiliation: National and Kapodistrian University of Athens
Email: konstantina.bereta[at]di.uoa.gr
George
Stamoulis is a Research Associate in the Dept. of Informatics and Telecommunications,
National and Kapodistrian University of Athens, and a PhD candidate under the supervision of
Prof. Koubarakis. He holds a Bsc. and Msc. from the Department of Informatics and
Telecommunications of the National and Kapodistrian University of Athens. His research interests
focus in the areas of Semantic Web, Data Visualization and Integration and User Interfaces.
Affiliation: National and Kapodistrian University of Athens
Email: gstam[at]di.uoa.gr
Despina-Athanasia Pantazi is a Research Associate in the Dept. of Informatics and
Telecommunications, National and Kapodistrian University of Athens, and a PhD candidate under
the supervision of Prof. Koubarakis. She holds a B.Sc. and M.Sc. from the Department of
Informatics and Telecommunications of the National and Kapodistrian University of Athens. Her
research interests focus in the areas of Artificial Intelligence and Semantic Web. As part of
her M.Sc. thesis, Despina has developed an extension of schema.org for annotating satellite
datasets.
Affiliation: National and Kapodistrian University of Athens
Email: dpantazi[at]di.uoa.gr
Dharmen Punjani is a Research Associate in the Dept. of Informatics and Telecommunications,
National and Kapodistrian University of Athens, and a PhD candidate under the supervision of
Prof. Koubarakis. He holds an M.Tech in Computer Engineering from Sardar Vallabhbhai National
Institute of Technology, Surat and a B.E. in Computer Engineering from Saradar Patel University,
New V.V.Nagar in India. His research interest focus on Question Answering, Natural Language
Processing, Semantic Web and Machine Learning. He has developed GeoQA, the first template-based
question answering engine over linked geospatial data.
Affiliation: National and Kapodistrian University of Athens
Email: dpunjani[at]di.uoa.gr
Theofilos Ioannidis is a software engineer and database administrator at Bank of Greece for the
Electronic Secondary Market of Greek Government Bonds. He has also designed and developed
information systems for the textile industry and software for Clearing and Settlement Houses for
the banking sector of several European countries. He is a Research Associate at the Dept. of
Informatics and Telecommunications, National and Kapodistrian University of Athens, and a PhD
candidate under the supervision of Prof. Koubarakis. He holds a Diploma in Electrical
Engineering from the Aristotle University of Thessaloniki and a Master of Science in Information
Systems Engineering from UMIST at Manchester, UK. He focuses on semantic big geospatial data
technologies and benchmarking in the same research area.
Affiliation: National and Kapodistrian University of Athens
Email: tioannid[at]di.uoa.gr
Dimitris Bilidas is a researcher at the Management of Data, Information and Knowledge group, in
the Dept. of Informatics and Telecommunications, National and Kapodistrian University of Athens.
He obtained a B.Sc. from Department of Informatics, University of Piraeus and a M.Sc. in
Advanced Information Systems from Department of Informatics and Telecommunications in National
and Kapodistrian University of Athens, where he is currently a PhD candidate under the
supervision of Professor Manolis Koubarakis, in the area of query languages for the Semantic Web
and Distributed Query Processing. Mr. Bilidas has extensive research experience in several Greek
and European research projects (ExtremeEarth, Optique, Copernicus App Lab, Indigo, Xenios).
Currently, in the context of the ExtremeEarth project he is developing solutions for distributed
geospatial analytics over large semantic web graph databases.
Affiliation: National and Kapodistrian University of Athens
Email: d.bilidas[at]di.uoa.gr
George Mandilaras is a Research Associate in the Dept. of Informatics and Telecommunications,
National and Kapodistrian University of Athens. He holds a B.Sc. from the Department of
Informatics and Telecommunications of the National and Kapodistrian University of Athens and he
is currently doing his M.Sc. in the field of data science the same university. His research
interests focus in the areas of Big Data, Artificial Intelligence and Semantic Web.
Affiliation: National and Kapodistrian University of Athens
Email: gmandi[at]di.uoa.gr
Nikolaos Karalis is a PhD candidate at the DICE research group of the University of Paderborn
under the supervision of Prof. Axel-Cyrille Ngonga Ngomo. He is currently working as an early
stage researcher in the Marie Skłodowska-Curie project KnowGraphs on the topic of knowledge
graph representation. He holds a BSc and a MSc from the Dept. of Informatics and
Telecommunications of the National and Kapodistrian University of Athens. During his MSc and
under the supervision of Prof. Manolis Koubarakis he developed YAGO2geo, a geospatial extension
of YAGO2.
Affiliation: DICE group, Department of Computer Science, Paderborn University
Email: nkaralis[at]mail.uni-paderborn.de
- CIKM 2018
tutorial: From Big Data to Big Information and Big
Knowledge: the Case of Earth Observation Data.
Tutorial at the 27th International Conference on Information and Knowledge Management 2018
Some particularly important rich sources of open and free big geospatial data are the Earth
observation programs of various countries such as the Landsat program of the US and the
Copernicus programme of the European Union. Earth observation data is a paradigmatic case of big
data and the same is true for the information and knowledge extracted from it. Earth observation
data (satellite images and in-situ data) and the information and knowledge extracted can be
utilized in many applications with financial and environmental impact in areas such as emergency
management, climate change, agriculture and security. This potential has not been fully realized
up to now, because Earth observation data and the information extracted from it “is hidden” in
various archives operated by NASA, ESA and national space agencies. Therefore, a user that would
like to develop an application needs to search in these archives, discover the needed data and
information and integrate it in his application. In this tutorial we show how to “break these
silos open” by publishing their data as RDF, enable their discovery by modern search engines,
interlink it with other relevant data, and make it freely available on the Web to enable the
easy development of geospatial applications. We present a complete data science pipeline that
starts with Earth Observation datasets in various formats that are made freely available in the
archives of space agencies like ESA and NASA, and ends with the deployment of an interactive
visual application that uses Earth Observation data together with other collateral data (e.g.,
open government data, closed enterprise data, model data etc.) using linked data technologies.
The tutorial will give an in-depth coverage of the techniques, systems and applications of
linked Earth observation data developed by the presenters in the last 8 years in the context of
5 European projects. Related work by other researchers will also be covered in depth. Finally,
open problems and directions for future research in this area will also be discussed.
Tutorial Overview
This is a half-day tutorial and will be held on Friday, October 26st. A brief overview is
provided below:
Part 1: Introduction. Satellite images. The Copernicus programme of the European
Union. Copernicus data as a paradigmatic case of big data.
Part 2: Database techniques for satellite data. In this part of the tutorial, we
will survey the state of the art array DBMS: MonetDB/SciQL, paradigm4/SciDB and rasdaman. We
will concentrate on the capabilities and existing applications of these systems for processing
remote sensing data.
Part 3: Knowledge discovery from satellite images. In this part of the tutorial,
we cover remote sensing literature that studies pattern recognition and machine learning
techniques for extracting knowledge (e.g., land cover classes) from satellite images.
Part 4: RDF and SPARQL extensions for geospatial and temporal data. In this part
of the tutorial, we will first discuss data models and query languages for geospatial and
temporal extensions of RDF concentrating on the data model stRDF and the query language stSPARQL
developed by our group, the Open Geospatial Consortium (OGC) Standard GeoSPARQL and the
extension of RDF for representing incomplete information RDFi. These spatiotemporal extensions
of RDF can be used for encoding the knowledge extracted from satellite images using the
techniques covered in Part 3 of the tutorial together with other collateral data (e.g., the
administrative divisions of a certain country, OpenStreetMap data etc.).
Part 5: Spatiotemporal RDF stores. In this part of the tutorial, we will present
Strabon, Ontop-spatial and their competitor systems (Parliament, uSeekM, GraphDB, AllegroGraph,
Virtuoso, Stardog and Oracle Spatial and Graph 12c) and a recent functional and performance
comparison of them using the benchmark Geographica. We will also discuss open problems such as
how to scale these systems to big data and how to represent and query raster data in the linked
data paradigm.
Part 6: Interlinking geospatial and temporal RDF data. In this part of the
tutorial, we will discuss work on geospatial entity resolution and more recent work on the
discovery of geospatial relations with systems such as Silk and Radon.
Part 7: Searching, browsing, exploring and visualizing remote sensing data and linked
spatiotemporal data. In this part of the tutorial, we will first discuss remote sensing
techniques for content-based retrieval from satellite image archives. We will also present our
tool Sextant for visualizing linked spatiotemporal data, and its use in an environmental
application from the project Copernicus App
Lab.
Tutorial material
Download Presentations: Part-1, Part-2, Part-3
Big linked
spatiotemporal data tools to be covered in the tutorial.
References
- Manolis Koubarakis, Konstantina Bereta, George Papadakis, Dimitrianos Savva and George
Stamoulis. Big, Linked Geospatial Data and Its Applications in Earth
Observation. IEEE Internet Computing July/August (2017), 87–91.
- Manolis Koubarakis, Kostis Kyzirakos, Charalampos Nikolaou, George Garbis, Konstantina
Bereta, Roi Doganinad Stella Giannakopoulou, Panayiotis Smeros, Dimitrianos Savva,
George Stamoulis, Giannis Vlachopoulos, Stefan Manegold, Charalampos Kontoes,
Themistocles Herekakis, Ioannis Papoutsis and Dimitrios Michail. Managing Big,
Linked, and Open Earth-Observation Data: Using the TELEIOS/LEO software stack. IEEE
Geoscience and Remote Sensing Magazine 4, 3 (2016), 23–37.
- Ying Zhang, Martin L. Kersten and Stefan Manegold. SciQL: array data processing
inside an RDBMS. SIGMOD Conference 2013: 1049-1052
- Milena Ivanova, Martin L. Kersten, Stefan Manegold and Yagiz Kargin. Data Vaults:
Database Technology for Scientific File Repositories. Computing in Science and
Engineering 15(3): 32-42 (2013)
- B. Chaudhuri, B. Demir, S. Chaudhuri and L. Bruzzone. Multilabel remote sensing
image retrieval using a semisupervised graph-theoretic method. IEEE Transactions on
Geoscience and Remote Sensing, 56(2):1144–1158, 2018.
- O. E. Dai, B. Demir, B. Sankur and L. Bruzzone. A novel system for content-based
retrieval of single and multi-label high-dimensional remote sensing images. IEEE
Journal of Selected Topics in Applied Earth Observations and Remote Sensing, pages 1–18,
2018.
Presenters
Konstantina Bereta is a Research Associate in the Dept. of Informatics
and Telecommunications, National and Kapodistrian University of Athens, and she holds a BSc. and
MSc. from the same department. She is also a PhD candidate under the supervision of Prof.
Manolis Koubarakis (expected date of graduation: Fall 2018). She has worked as a scientific
programmer and research associate in several EU FP7 projects. Her research interests focus in
the areas of spatiotemporal databases, Semantic Web and Cloud Computing.
Stefan
Manegold is the lead of the Database Architectures group of CWI and a Professor in
Leiden University. He is a nationally and internationally recognized expert in system-oriented
database research. He is particularly known for his pioneering work on hardware-conscious
database technology, and for disseminating his research via the open-source columnar analytical
database management system MonetDB, which is widely used in academia and business. Dr.
Manegold’s research is focused on bridging the gap between database architectures and demanding
applications areas, such as large-scale data analytics (Big Data), data intensive scientific
discovery (eScience), and semantic web. His expertise comprises database architectures, query
processing algorithms, and data management technology, with a particular focus on hardware-
conscious algorithms and data structures, query optimization, scalability, performance,
benchmarking and testing.
Manolis
Koubarakis is a Professor in the Dept. of Informatics and Telecommunications, National
and Kapodistrian University of Athens. He previously held positions at the Dept. of Electronic
and Computer Engineering, Technical University of Crete (Assistant and Associate Professor), the
Dept. of Informatics, University of Athens (Visiting Researcher), the Dept. of Computation,
UMIST (now University of Manchester) (Lecturer) and the Dept. of Computing, Imperial College,
London (Research Associate). He has published more than 180 papers that have been widely cited
in the areas of Artificial Intelligence (especially Knowledge Representation), Databases,
Semantic Web and Linked Data. In 2015, he was elected Fellow of the European Association of
Artificial Intelligence (EurAI). He has served in the program committee of various international
conferences and workshops, and he has organized various international events. He has attracted
more than 6M Euros in funding from the European Commission, the Greek General Secretariat from
Research and Technology, the European Space Agency and industry sources.
George
Stamoulis is a Research Associate in the Dept. of Informatics and Telecommunications,
National and Kapodistrian University of Athens, and a PhD candidate under the supervision of
Prof. Koubarakis. He holds a Bsc. and Msc. from the Department of Informatics and
Telecommunications of the National and Kapodistrian University of Athens. His research interests
focus in the areas of Semantic Web, Data Visualization and Integration and User Interfaces.
Begüm Demir is a
Professor and Chair of the Remote Sensing Image Analysis (RSiM) group at the Faculty of
Electrical Engineering and Computer Science, Technische Universitat Berlin (TU Berlin), Germany.
Before joining to TU Berlin, she was an Assistant Professor at the Department of Computer
Science and Information Engineering, University of Trento, Italy, from 2013 to 2017 while in
2017 she became an Associate Professor at the same department. Her main research interests
include machine learning and big data management with applications to remote sensing image
analysis. She was a recipient of an ERC Starting Grant with the project “BigEarth- Accurate and
Scalable Processing of Big Data in Earth Observation’ in 2017 and the IEEE Geoscience and Remote
Sensing Society Early Career Award in 2018. She is a senior member of IEEE since 2016.
- ISWC 2017
tutorial: ReQuLGD: Representation and Querying for
Linked Geospatial Data.
Tutorial at the 16th International Semantic Web Conference 2017
The Web of data has recently been populated with linked geospatial data as various geospatial
data sources have been transformed into RDF and added to the linked data cloud (e.g., Geonames,
Open Street Map, CORINE land cover etc.). Therefore, it is important to study how to represent
geospatial data in RDF and how to query it using SPARQL. Researchers from the areas of Semantic
Web and Linked Data have studied theses problems recently. The results of this research has been
the development of geospatial extensions of RDF and SPARQL, and the implementation of geospatial
RDF stores. In this tutorial, we present a comparative survey of current research in this area
and point to directions for future work.
Tutorial Overview
This is a half-day tutorial and was held on Saturday, October 21st, in the afternoon. A brief
overview is provided below:
Part 1: Introduction
Part 2: Data models and query languages for linked geospatial data. We survey the recent
geospatial extensions of RDF and SPARQL concentrating on the OGC standard GeoSPARQL and our own
language stSPARQL. We also discuss proposals for geospatial Ontology Based Data Access (OBDA)
with more emphasis on the OBDA framework of our system Ontop-spatial. Finally, we discuss the
problem of querying incomplete geospatial information expressed using Semantic Web
standards.
Part 3: Implemented Systems. In this part of the tutorial, we present systems for storing
and querying linked geospatial data. We distinguish these implementations into two categories:
geospatial RDF stores and geospatially-enabled OBDA systems. We will describe the architectures
of the surveyed systems and we will compare them in terms of functionality and performance.
Demos of Strabon and Ontop-spatial will also be given by the presenters.
Part 4: Open issues. This last part of this tutorial will be dedicated to the discussion
of open issues. We will point out open problems in the area of data models and query languages,
and we will discuss how we can improve the performance of GeoSPARQL query engines, both native
and OBDA. For the latter problem, we will discuss how state-of-the-art approaches in the area of
big geospatial data, and big RDF data query processing can be used to improve the performance of
existing GeoSPARQL query engines.
Tutorial material
1. Github repository with examples
(software, datasets, etc.) that will be used in the tutorial.
2. Strabon
website
3. Geographica
Download Presentation.
References
- Open Geospatial Consortium. GeoSPARQL - A geographic query language for RDF
data. OGC Candidate Implementation Standard, 2012.
- M. Koubarakis and K. Kyzirakos. Modeling and Querying Metadata in the Semantic
Sensor Web: The Model stRDF and the Query Language stSPARQL. In Proceedings of the
7th Extended Semantic Web Conference, volume 6088 of LNCS, pages 425–439. Springer, 2010.
- K. Kyzirakos, M. Karpathiotakis, and M. Koubarakis. Strabon: A Semantic Geospatial
DBMS. In Proceedings of the 11th International Semantic Web Conference, volume 7649
of LNCS, pages 295–311. Springer, 2012.
- C. Nikolaou and M. Koubarakis. Querying incomplete information in RDF with
SPARQL. Artificial Intelligence, 237:138 – 171, 2016.
- K. Bereta and M. Koubarakis. Ontop of Geospatial databases. In Proceedings of
the 15th International Semantic Web Conference, Kobe, Japan, October 17–21, pages 37–52.
Springer International Publishing, 2016.
- S. Brüggemann, K. Bereta, G. Xiao, and M. Koubarakis. Ontology-Based Data Access
for Maritime Security. In Proceedings of the 13th Extended Semantic Web Conference,
Heraklion, Crete, Greece, May 29 - June 2, 2016, pages 741–757, 2016
- D. Calvanese, G. De Giacomo, D. Lembo, M. Lenzerini, A. Poggi, and R. Rosati.
Ontology-based Database Access. In Proceedings of the Fifteenth Italian Symposium on
Advanced Database Systems, SEBD 2007, 17-20 June 2007, Torre Canne, Fasano, BR, Italy, pages
324–331, 2007.
- G. Garbis, K. Kyzirakos, and M. Koubarakis. Geographica: A Benchmark for
Geospatial RDF stores (long version). In Proceedings of the 12th International
Semantic Web Conference, volume 8219 of Lecture Notes in Computer Science, pages 343–359.
Springer, 2013.
Presenters
Manolis
Koubarakis is a Professor in the Dept. of Informatics and Telecommunications, National
and Kapodistrian University of Athens. He is a EurAI fellow. He previously held positions at the Dept. of Electronic
and Computer Engineering , Technical University of Crete (Assistant and Associate Professor),
the Dept. of Informatics, University of Athens (Visiting Researcher), the Dept. of Computation,
UMIST(now University of Manchester) (Lecturer) and the Dept. of Computing, Imperial College,
London (Research Associate). He has published more than 170 papers that have been widely cited
in the areas of Artificial Intelligence (especially Knowledge Representation), Databases,
Semantic Web and Linked Data. He previously held positions at the Dept. of Electronic and
Computer Engineering , Technical University of Crete (Assistant and Associate Professor), the
Dept. of Informatics, University of Athens (Visiting Researcher), the Dept. of Computation,
UMIST(now University of Manchester) (Lecturer) and the Dept. of Computing, Imperial College,
London (Research Associate). He currently teaches the following university courses: Artificial
Intelligence, Knowledge Technologies and Data Structures and Programming Techniques. His
research has been funded by the European Commission, the Greek General Secretariat for Research
and Technology and industry sources.
Konstantina Bereta is a research associate at the Management of Data,
Information and Knowledge group, in the Dept. of Informatics and Telecommunications, National
and Kapodistrian University of Athens. She is also a PhD candidate under the supervision of
prof. Manolis Koubarakis and holds a BSc. and MSc. from the same department. She has worked as a
scientific programmer and research associate in several EU FP7 projects. Her research interests
focus in the areas of spatiotemporal databases, Semantic Web and Cloud Computing. She is the
developer of Ontop-spatial, a geospatial extension of the system Ontop, which is
currently the most efficient OBDA solution for geospatial information.
- ESWC 2015 tutorial:
Publishing and Interlinking Linked Geospatial Data.
- RW
2012 tutorial: Data Models and Query Languages for Linked Geospatial Data.
Data Models and Query Languages for Linked Geospatial Data
On September 6, 2012 Manolis Koubarakis, Kostis Kyzirakos and Charalampos Nikolaou presented an
invited tutorial on data modeling, querying and reasoning for linked geospatial data in the
Reasoning Web Summer School which took place in Vienna.
The topics covered in the tutorial together with the relevant slides are given below:
1. Introduction [pdf]
2. Background in geospatial data modeling [pdf]
3. Geospatial data in RDF - stSPARQL [pdf]
4. Geospatial data in RDF - GeoSPARQL [pdf]
5. Implemented RDF Stores with geospatial support [pdf]
6. Geospatial information with description logics, OWL and rules [pdf]
7. Conclusions, questions, discussion [pdf]
There is also an accompanying tutorial paper:
- M. Koubarakis, M. Karpathiotakis, K. Kyzirakos, C. Nikolaou, and M. Sioutis. Data
Models and Query Languages for Linked Geospatial Data. Invited tutorial at the 8th
Reasoning Web Summer School 2012 (RW 2012), Austria, Vienna, 03-08 September, 2012. [pdf]
For some more interesting tutorials given at the Reasoning Web Summer School see http://www.kr.tuwien.ac.at/events/rw2012.
- ESWC 2012
tutorial: Data models, Query Languages, Implemented
Systems and Applications of Linked Geospatial Data.
Data models, Query Languages, Implemented Systems and Applications of Linked Geospatial Data
In this tutorial we survey the state of the art in data models, query languages, implemented
systems and applications of linked geospatial data. Many kinds of geospatial data are becoming
available as linked datasets given the proliferation of geospatial information on the Web (e.g.,
Google and Bing maps, user-generated geospatial content etc.). The topic of the tutorial is
related to all core research areas of the Semantic Web (e.g., semantic information extraction,
data modeling and ontologies, querying, reasoning, implemented systems etc.) since there is
often a need to re-consider existing core techniques when we deal with geospatial information.
Thus, it is timely to train Semantic Web researchers, especially the ones that are in the early
stages of their careers, on the state of the art of this area and invite them to contribute to
it.
Tutorial description
We have recently witnessed a proliferation of geospatial data on the Web. In addition to
professionally-produced material being offered for free (e.g., Google or Bing maps), the public
has also been encouraged to make geospatial content, including their geographical location,
available online. The volume of such geospatial Web content is already big and constantly
growing.
Semantic Web researchers and practitioners have also started to make geospatial data available as
linked data (e.g., Ordnance Survey, Great Britain's national mapping agency, makes available
some of its geospatial data as linked data (http://data.ordnancesurvey.co.uk/.html), the portal LinkedGeoData makes
OpenStreetMap data are made available as RDF (http://linkedgeodata.org/ etc.). Since a lot of data useful to the wider
public is geospatial (e.g., open government data), we expect this trend to continue in the near
future.
In this tutorial we will present the state of the art in data models, query languages and
implemented systems for linked geospatial data i.e., geospatial data expressed in RDF.
Intended audience - Prerequisite knowledge
The tutorial is targeted towards Semantic Web researchers in the early stages of their career.
The prerequisite is good knowledge of RDF and SPARQL and some knowledge of other Semantic Web
technologies (OWL, RDF stores, linked data). Knowledge of geospatial technologies is not a
prerequisite and will be covered in some depth.
Detailed description
14:00-14:15 Introduction [Presentation: ppt | pdf]
14:15-15:00 Background in geospatial data modeling [Presentation: ppt | pdf]
- GIS concepts and vocabulary
- Geographic space modeling and representation (vector space representation, half-space
representation)
- Co-ordinate systems
- Relevant OGC standards (Well Known Text, Geography Markup Language)
15:00-15:30 Geospatial data in the Semantic Web - stSPARQL [Presentation: ppt | pdf]
- Representing geospatial data in stRDF
- Examples of publicly available linked geospatial data
- Querying geospatial data using stSPARQL
15:30-16:00 Coffee Break
16:00-16:30 Geospatial data in the Semantic Web - GeoSPARQL [Presentation: ppt | pdf]
- The query language GeoSPARQL.
16:30-16:45 Implemented systems [Presentation: ppt | pdf]
- Survey of implementations of stSPARQL, GeoSPARQL and other research prototypes
- Survey of geospatial features in well-known RDF stores
16:50-17:00 Applications [Presentation: ppt | pdf]
- Survey of existing applications of linked geospatial data. Emphasis on an application the
presenters have developed on Earth Observation data.
17:00 - 17:15 Conclusions, questions, discussion [Presentation: ppt | pdf]
17:15 - 17:30 Demo of Strabon
Presenter CVs
Manolis Koubarakis is a Professor in the Dept. of Informatics and Telecommunications,
National and Kapodistrian University of Athens. He has a degree in Mathematics from the
University of Crete, an M.Sc. in Computer Science from the University of Toronto, and a Ph.D. in
Computer Science from the National Technical University of Athens. He joined his current
department in September 2005 as an Associate Professor and was promoted to Professor in April
2011. Before coming to Athens, he has been an Assistant and Associate Professor in the Dept. of
Electronic and Computer Engineering, Technical University of Crete, and a Lecturer in the Dept.
of Computation, University of Manchester – Institute of Science and Technology (UMIST). Manolis
has published more than 100 papers that have been widely cited in the areas of Artificial
Intelligence (especially Knowledge Representation), Databases, Semantic Web and P2P Computing.
His research has been financially supported by the European Commission (projects CHOROCHRONOS,
DIET, BRIDGEMAP, Evergrow, OntoGrid, SemsorGrid4Env and TELEIOS), the Greek General Secretariat
for Research and Technology and industry sources (Microsoft Research and British
Telecommunications). He is currently co-ordinating project TELEIOS (http://www.earthobservatory.eu/)
which is building an Earth Observatory using a combination of technologies based on semantics
(geospatial extensions of RDF and SPARQL) and array extensions of SQL. Manolis has 16 years
teaching experience in academic institutions in Greece and the United Kingdom, and has given
many talks in international conferences and workshops (some of them invited). He has served as
Tutorial chair for ESWC 2011.
Kostis Kyzirakos is a researcher in the Department of Informatics and Telecommunications,
University of Athens. He received his Diploma in Engineering from the School of Electrical and
Computer Engineering, NTUA, Athens. He has participated in projects funded by the European
Commision (Ontogrid, SemsorGrid4Env, TELEIOS) and the Greek General Secretariat for Research and
Technology (P2P Techniques for Semantic Web Services). He is one of the main developers of the
semantic geospatial DBMS Strabon that was developed in the context of the EU projects
SemsorGrid4Env and TELEIOS. In the same context, he studied and proposed how to represent and
query geospatial data in the Semantic Web, published various geospatial datasets as linked
geospatial data and implemented applications combining these data with previously published
linked geospatial data. His current research focuses on modeling and querying semantic
spatio-temporal information on top of traditional DBMS. He has given a tutorial on building
semantic sensor webs and applications at ESWC 2011.
Manos Karpathiotakis is a researcher in the Department of Informatics and
Telecommunications, University of Athens. He received his Bachelor degree and his Master of
Science from the Department of Informatics and Telecommunications of the University of Athens.
He has participated in projects funded by the European Commision (TELEIOS, SemsorGrid4Env) and
he is one of the main developers of the semantic geospatial DBMS Strabon that was developed in
the context of these projects. In the same context, he published various geospatial datasets as
linked geospatial data and implemented applications combining these data with previously
published linked geospatial data. His current research focuses on the overlapping areas of
Geospatial Semantic Web, Semantic Sensor Web and Linked Data.
