School of Computing

Luana Micallef

Visiting Research Fellow

Photo of L Micallef, if available
  • Room --
    School of Computing
    University of Kent,
    CT2 7NF


My publications are available from the University of Kent's Academic Repository.

Research Interests

I belong to the following research groups:


I am an Honorary Research Fellow at the University of Kent, UK and a Postdoctoral Researcher at the Helsinki Institute for Information Technology HIIT, Finland (details 'About Me' below).
This webpage focuses on my ongoing and past research with the University of Kent.
For details about my current postdoctoral work, please visit my HIIT webpage.

My general research interests are: information visualization, visual design and analytics, and human-computer interaction. In particular, I have been interested in set visualizations, diagram layout and diagram aesthetics, reasoning with diagrams. For my PhD, I investigated the visualization of set relations and cardinalities using Venn and Euler diagrams.

Other research interests include: computer-supported cooperative work, multi-touch and surface computing, domain specific language design, functional programming, formal methods, computer-assisted learning, technology for developing markets.




I investigated the effectiveness of different visualization techniques in depicting set relations and related quantitative data intuitively and in facilitating reasoning and data analysis for diverse application areas. A number of empirical studies have been conducted using Amazon Mechanical Turk (e.g., [ Diagrams 2014 paper ]). I also co-authored a paper on the state-of-the-art of set visualizations [ EG/IEEE EuroVis 2014 paper | survey webpage ].

I collaborated on this research with Helen Purchase (University of Glasgow, UK), Peter Rodgers (University of Kent, UK), Gem Stapleton and Peter Chapman (University of Brighton, UK), and Bilal Alsallakh (Vienna University of Technology, Austria).


PhD Project Summary

Luana Micallef (2013). Visualizing Set Relations and Cardinalities Using Venn and Euler Diagrams. PhD thesis,
            University of Kent, UK.
Examiners: Mateja Jamnik (University of Cambridge, UK), Colin Johnson (University of Kent, UK)

In medicine, genetics, criminology and various other areas, Venn and Euler diagrams are used to intuitively visualize data set relations and their cardinalities. The data sets are represented by closed curves and the data set relationships are depicted by the overlaps between these curves. Examples of Venn and Euler diagrams are illustrated further down.

Both the sets and their intersections are intuitively visible as the closed curves are preattentively processed (Treisman and Souther, 1985) and form common regions that have a strong perceptual grouping effect (Palmer, 1992). Besides set relations such as intersection, containment and disjointness, the cardinality of the sets and their intersections can also be depicted in the same diagram (referred to as area-proportional) through the size of the curves and their overlaps. Size is a preattentive feature (Treisman, 1985) and so similarities, differences and trends are easily identified (Treisman and Gelade, 1980). Thus, such diagrams facilitate data analysis and reasoning about the sets. Yet, drawing these diagrams manually is difficult, often impossible, and current automatic drawing methods do not always produce appropriate diagrams.

For my PhD, I developed the following novel generation and layout techniques and software to automatically draw accurate and intuitive Venn and Euler diagrams:

eulerForce: Laying Out Euler Diagrams Using a Force-Directed Approach

The first method that uses a force-directed approach to automatically lay out Euler diagrams in relatively fast time

[ JVLC paper | extended abstract and poster at IEEE InfoVis 2009 ];

eulerAPE: Drawing Area-Proportional Euler and Venn Diagrams Using Ellipses

The first method that uses ellipses to automatically draw accurate, yet intuitive area-proportional Venn diagrams (and some Euler diagrams) with three curves

[ PLoS ONE paper | Euler Diagrams 2014 paper | poster for the ACM SRC at GHC 2012 ];

eulerGlyphs: Drawing Area-Proportional Euler Diagrams With Glyphs

The first method that automatically draws area-proportional Euler diagrams, glyph representations and Euler diagrams with glyphs for probabilistic judgement

[ video using one of eulerGlyphs’s Euler diagrams with glyphs to intuitively explain the classic Bayesian problem on mammography which even doctors get wrong (Eddy, 1982) ].

Below are examples of the diagrams generated by eulerForce, eulerAPE and eulerGlyphs.
eulerForce: Laying Out Euler Diagrams Using a Force-Directed Approach eulerAPE: Drawing Area-Proportional Euler and Venn Diagrams Using Ellipses eulerGlyphs: Drawing Area-Proportional Euler Diagrams With Glyphs
Using these drawing methods, accurate and intuitive diagrams can be generated for diverse application areas. These diagrams facilitate analysis of data set relations and their intersection cardinalities. Thus, they can assist users in knowledge discovery and decision-making.

Apart from these drawing methods, I also:

devised analytic geometry methods to instantaneously compute the overlapping areas of three general intersecting ellipses, one of which is used by eulerAPE;

evaluated the effectiveness of ellipses in drawing accurate area-proportional Venn diagrams for 3-set data and the characteristics of the data that can be depicted accurately with ellipses, by analysing the area-proportional diagrams generated by eulerAPE for 10,000 random 3-set data;

conducted a user study to assess the effect of eulerGlyphs’s visualizations on Bayesian reasoning through crowdsourcing using Amazon Mechanical Turk and identified ways how such visualizations could be combined with textual information to facilitate reasoning [ IEEE InfoVis 2012 paper | study webpage ].

The latter user study on Bayesian reasoning has been presented at the IEEE InfoVis 2012, part of IEEE VIS (formerly VisWeek) 2012 conference, where it received one of three Best Paper Honourable Mention Awards [ paper | presentation | fast forward ]. Details of the study are available here. The drawing method eulerGlyphs as well as this user study were completed during my four-month internship with the AVIZ team at INRIA Saclay Île-de-France where I worked with Pierre Dragicevic and Jean-Daniel Fekete. This internship and thus this research work was funding by INRIA.

My other PhD research work was funded by a scholarship from the University of Kent and a grant from The Allan & Nesta Ferguson Charitable Trust, and supervised by Peter Rodgers (University of Kent, UK). I am also grateful to Angela Morelli (Graphic and Information Designer) for her feedback on the design of the diagrams and Gem Stapleton (University of Brighton, UK) for her advice on how this work could, in the future, aid in the formalization of analytic methods that would determine whether an accurate area-proportional Euler diagram can be drawn with ellipses for specific data.


Professional Activities

SetVR Steering Committee Member of SetVR (International Workshop on Set Visualization and Reasoning)
Graduate Symposium Chair of Diagrams 2016
IEEE VIS 2015 Logo Fast Forward & Video Previews Chair of IEEE VIS 2015
with Christoph Garth (Kaiserslautern University of Technology, Germany)
and Tom Peterka (Argonne National Laboratory, IL, USA)
IEEE VIS 2014 Logo Fast Forward Chair of IEEE VIS 2014
with Bilal Alsallakh (Vienna University of Technology, Austria)
EuroVis 2014 Logo Fast Forward Chair of EG/IEEE EuroVis 2014
with Christoph Garth (Kaiserslautern University of Technology, Germany)
JVLC VRED 2014 Logo Guest Editor of the Journal of Visual Languages and Computing on
Visualization and Reasoning Using Euler Diagrams (V25N1, February 2014)
with Peter Chapman (University of Brighton, UK)
[ special issue ]
IEEE VIS 2013 Logo Fast Forward Chair of IEEE VIS 2013
with Fanny Chevalier (University of Toronto, Canada)
ED2012: 3rd International Workshop on Euler Diagrams Logo General Chair of Euler Diagrams 2012
with Peter Chapman (University of Brighton, UK)
[ proceedings ]
I have served on the Programme Committee of:
  • VLC 2015 — 2015 International Workshop on Visual Languages and Computing
  • IEEE PacificVis 2015 — 8th IEEE Pacific Visualization Symposium [Visualization Note Committee]
  • Euler Diagrams 2014 — 4th International Workshop on Euler Diagrams
  • AVI 2014 — 12th International Working Conference on Advanced Visual Interfaces
I review papers for the following
  • Conferences
    • IEEE InfoVis: 2014, 2015
    • IEEE VAST: 2015
    • IEEE SciVis: 2014, 2015
    • EG/IEEE EuroVis: 2014, 2015
    • IEEE PacificVis: 2015
    • AVI: 2014
    • VLC: 2015
    • Euler Diagrams: 2014
    • ESANN: 2015
  • Journals:
    • IEEE Transactions on Visualization and Computer Graphics: 2015
    • Computers & Graphics: 2014
    • Journal of Visual Languages and Computing: 2014
    • Journal of Logic, Language and Information: 2014
    • Mind & Society: 2015



In the past years, I was an assistant lecturer for the following modules:

In 2010/2011, I also gave some lectures for CO325 (Foundations of Computing II).
In 2011/2012, I taught VALUE and VALUE-Lite sessions for CO322 and CO325 (Foundations of Computing I and II).
As a Credit in Higher Education, in 2010, I completed the Associate Teacher Accreditation Programme (ATAP), which is run by the University's Unit for the Enhancement of Learning and Teaching.


About Me

As from 19th May 2014, I am a Postdoctoral Researcher at the Helsinki Institute for Information Technology HIIT, Finland (a joint research institute of Aalto University and the University of Helsinki). I am working with Giulio Jacucci and Samuel Kaski on an EU funded project MindSee and a Tekes funded project Reknow with the aim of combining information visualizaton, human-computer interaction, brain-computer interface technology, statistical machine learning and probabilistic modelling to facilitate information search and retrieval, and sense-making. More information on my HIIT webpage.

In September 2013, I completed my PhD and I was appointed a Research Fellow in the School of Computing, University of Kent, UK. On the 19th May 2014, I obtained Honorary Status in the same School.

In 2012, I was awarded a National Security Agency (NSA) Scholarship (over 1,000 applicants) to attend the 2012 Grace Hopper Celebration of Women in Computing (GHC 2012) in Baltimore, MD, USA, after my PhD work was accepted for presentation at the PhD Forum of GHC 2012. I was also selected to participate in the ACM Student Research Competition (SRC) at GHC 2012 with my software eulerAPE and I was awarded an ACM SRC Travel Award.
[ GHC 2012 PhD Forum Paper | ACM SRC 2012 and GHC 2012 Poster | GHC 2012 Scholarships ]

In 2012, I was awarded The Allan & Nesta Ferguson Charitable Trust Grant covering the tuition fees for the final year of my PhD

In April 2011, I was selected as a finalist for the Google Anita Borg Memorial Scholarship: Europe, the Middle East and Africa (EMEA) and I was invited to attend the EMEA Scholars' Retreat 2011 at Google Zurich. In honour of Dr Anita Borg who founded the Institute for Women and Technology, this scholarship aims to celebrate women’s achievements in computing and technology.
[ Scholars and Finalists | Announcement on the Google Blog and Google Student Blog | EMEA Scholars' Retreat 2011 Video ]

In 2011, I was awarded a four-month internship at AVIZ, INRIA Saclay Île-de-France to investigate the use and benefits of Euler diagrams to reason about probabilistic and uncertain data in areas such as Bayesian reasoning. Our paper, Assessing the Effect of Visualizations on Bayesian Reasoning through Crowdsourcing, was accepted at the IEEE InfoVis 2012, part of IEEE VIS (formerly VisWeek) 2012 conference, where it received one of three Best Paper Honourable Mention Awards.
[ Paper | Video | Presentation | Fast Forward | Study webpage | eulerGlyphs ]

In December 2008, I was awarded a First Class Honours degree for my four-year Bachelor of Science in Information Technology (Honours) course (Computer Science as the main area of study) at the University of Malta, and a Faculty of ICT Dean's Award for Excellence in ICT. For my final year project, I designed and embedded a domain specific language in Haskell to model, transform and quality assure business processes in business-driven development. In particular, this language captures the domain semantics of IBM's WebSphere Business Modeler Advanced.
[ BSc IT (Hons) Thesis | Technical Report | Paper | Poster ]

In 2007, my friends and I made it to the finals of Microsoft Imagine Cup in South Korea, with our project KIKI (Key to the Integration of Knowledge and Innovation). Since the theme for 2007 was 'Imagine a world where technology enables a better education for all', we developed a platform to deploy educational software through an extensible architecture which provides inherent support for Windows MultiPoint functionality, inter-computer communication, user identification and progress tracking.
[ Paper | Our official team website | Video at the Finals ]

Following our participation in Microsoft Imagine Cup 2007, our team was awarded a four-month internship in summer 2008 at Microsoft Research India (MSRI), for the best use of Microsoft's new technology, Windows MultiPoint. We joined the Technology for Emerging Markets Group and as part of the Education Research Group, we were involved in a number of projects in relation to education in developing regions. We worked in collaboration with a number of rural schools and non-governmental organizations in the region, and we implemented software prototypes and conducted field trails, pilot projects and empirical studies to evaluate the impact of digital technology in the classroom on learning outcomes.
[ Paper | MSRI project web page | MSRI new software release | US Patent ]

In summer 2007, I was chosen to participate in the CERN Summer Student Programme 2007. I worked with the SPI group in the PH-SFT department and during my two-month studentship under the supervision of Stefan Roiser, I designed and implemented the SPI installation manager to uniformly install software packages developed by the LCG/AA (LHC Computing GRID/Applications Area) on different WLCG (Worldwide LHC Computing Grid) machines that are using and analysing data generated by the LHC experiments.

School of Computing, University of Kent, Canterbury, Kent, CT2 7NF

Enquiries: +44 (0)1227 824180 or contact us.

Last Updated: 12/12/2018