Dr Marian-Andrei Rizoiu

Since March 2016, I am a Research Fellow with the College of Engineering and Computer Science at the Australian National University in Canberra. I am equally affiliated with the Data61 unit of CSIRO, in the Decision Sciences team.



Between May 2014 and February 2016,I was a researcher within the National ICT Australia in Canberra Australia, working in the Optimization Research Group. I was equally an adjunct lecturer with the College of Engineering and Computer Science at the Australian National University in Canberra.

Between September 2013 and May 2014, I was a PostDoctoral researcher with the ERIC Laboratory, financed by the ImagiWeb Research Project. I was equally an assistant professor with the DIS Department, at the University Lumière in Lyon.

Between 2009 and 2013, I was a PhD student at the ERIC Laboratory with the University Lumière Lyon2, under the supervision of Stéphane Lallich and Julien Velcin. I defended my PhD thesis on June 24th 2013, with honors "Très Honorable".


My research revolves around artificial intelligence, machine learning and data mining. More specifically, I am interested in Social Network Analysis, popularity prediction, knowledge injection into non-supervised learning algorithms, data representation and temporal evolutions. I deal with large datasets of complex data (textual, image), often issued from the online social media and my main tools are modeling and simulation, clustering and topic modeling.

A little more details

My current research interest is to model theoretically popularity on online media, as well as estimate the influence of media content and network characteristics on online attention. We established a generative model that predicts online attention, based on an exogenously-driven Hawkes self-exciting processes. We also examine the geographical diffusion of media content over time and the goal is to generate statistical descriptions of content diffusion over time and geographical areas. We are handling very large Twitter datasets (the network), which relate to Youtube videos (the content).

My previous work dealt with how partial expert information can be leveraged into a non-supervised learning algorithm that treats complex data. This complex data is of different natures (text, image), it is temporal and structured, linked to knowledge repository (e.g. ontology) and/or labeled. Semi-supervised clustering is used to model the additional information (structure, labels, time) and to inject the heterogeneous information into the learning algorithm. A series of application emerge from the theoretical research: using the temporal dimension to detect temporal patters and typical evolutions, using the image labels to improve image numerical representation and an automatic topic evaluation using concept trees.



Conference proceedings

  • M.-A. Rizoiu, L. Xie, T. Caetano, and M. Cebrian "Evolution of Privacy Loss on Wikipedia, " in Proc. International Conference on Web Search and Data Mining (WSDM '16), 2016.
    preprint + SI:        slides:        poster:        bibtex:        Presentation page
  • Y.-M. Kim, J. Velcin, S. Bonnevay, and M.-A. Rizoiu, "Temporal Multinomial Mixture for Instance-Oriented Evolutionary Clustering, " in Proc. European Conference on Information Retrieval (ECIR '15), 2015, pp. 593–604.
    preprint:        bibtex:
  • M.-A. Rizoiu, "Semi-Supervised Structuring of Complex Data, " in Proc. Doctoral Consortium of the International Joint Conference on Artificial Intelligence (IJCAI '13), 2013, pp. 3239–3240.
    preprint:        slides:        poster:        bibtex:
  • M.-A. Rizoiu, J. Velcin, and S. Lallich, "Structuring typical evolutions using Temporal-Driven Constrained Clustering," in Proc. International Conference on Tools with Artificial Intelligence (ICTAI '12), 2012, pp. 610–617.
    preprint:        slides:        bibtex:
  • C. Musat, J. Velcin, S. Trausan-Matu, and M.-A. Rizoiu, "Improving topic evaluation using conceptual knowledge," in Proc. International Joint Conference on Artificial Intelligence (IJCAI '11), 2011, pp. 1866–1871.
    preprint:        bibtex:
  • C. Musat, J. Velcin, M.-A. Rizoiu, and S. Trausan-Matu, "Concept-based Topic Model Improvement," in Proc. International Symposium on Methodologies for Intelligent Systems (ISMIS '11), 2011, pp. 133–142.
    preprint:        bibtex:
  • M.-A. Rizoiu, J. Velcin, and J.-H. Chauchat, "Regrouper les données textuelles et nommer les groupes à l'aide des classes recouvrantes," in Proc. Extraction et Gestion des Connaissances (EGC '10), 2010, pp. 561–572.
    preprint:        slides:        bibtex:

Book chapters

  • M.-A. Rizoiu and J. Velcin, "Topic Extraction for Ontology Learning," in book: Ontology Learning and Knowledge Discovery Using the Web: Challenges and Recent Advances, pp. 38–61, 2011.
    preprint:        bibtex:

PhD thesis

  • M.-A. Rizoiu, "Semi-Supervised Structuring of Complex Data," PhD Thesis, University Lumière Lyon 2, June, 2013.
    preprint:        abstract:        slides:        short version:        abstract:        bibtex:

Masters thesis

  • M.-A. Rizoiu, "Textual Data Clustering and Cluster Naming," Master's Dissertation, 2009.
    preprint:        slides:        bibtex:

Mr Sina Eghbal »

Masters Student

Mr Quyu Kong »

Honours Student

Mr Yifei Zhang »

Masters Student

Mr Rui Zhang »

Masters Student

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