Nth-Iteration Lab

Measuring beauty

In a recent project we used Lock in Feedback to “converge” to the most beautiful face using sequential observations. The measurement tool we used was developed by Robin van Emden and is quite cool. He is now sharing it here: http://pavlov.tech/2016/10/21/facial-aspect-ratio-explorer/


ERC and Palgrave

Hi All,

The last few weeks have been busy teaching a new course called “Data Statistics”; I am teaching the course together with Prof. Dr. Edwin van den Heuvel and its pretty awesome. We will try to share the lecture notes here soon.

Also, good news, our (Robin van den Emden, Davide Iannuzzi, and Maurits Kaptein) paper on the decoy effect has been accepted by Palgrave Communications; we are awaiting the proofs and will than share a copy.

Finally, I have submitted an ERC starting grant application; here is the abstract:

“In 2011 Amazon.com listed the book The Making of a Fly for a mere $23,698,655.93 (plus $3.99 shipping). The incident is a famous example of autonomous decision making by computers gone awry. As humorous as this glitch may be, erroneous decisions by computers could well be far less amusing; what if your digital health assistant gives you the fully automated and fully personalized, but also quite deadly, recommendation to take 15 grams of paracetamol?

On the other hand, computers could be extremely helpful for making sequential decisions in the face of uncertainty. It is not far-fetched that a computer could learn the exact dosage of paracetamol that is best for you personally, outperforming your general practitioner. These algorithms already exist in a narrow sense; in online selling, for example, the prices of products are often automatically determined and personalized. However, these algorithms are not feasible outside the online selling domain since their success depends on assumptions that are violated in other domains. Furthermore, existing methods can be regarded as a “black box,” because it is unclear why a given result is produced. When similar methods are used in impactful domains such as healthcare, this lack of information is unacceptable: we need to keep the human in the loop to inspect, and possibly alter, computer-suggested decisions. Finally, when these algorithms are used to select personalized treatments, we need to ensure the privacy of the people involved.

Combining my expertise in human-computer interaction (HCI) and methods for sequential decision making, I have designed a research program to develop responsible methods for shared sequential decision making by computers and humans. The program is developed in four projects in which my team and I will relax current assumptions, allow humans to inspect and alter computer-generated decisions, and develop methods to ensure privacy when sequential decision algorithms are used to personalize treatments.”

Let’s see how that goes….

Finally, our data science program is alive and kicking with many cool events (check http://www.jads.nl), and my new book is coming up…

After summer update


After some silent weeks in summer, a little update. Over summer a number of articles that we worked on before summer have been accepted / published. Let’s do a little list:

  1. Bayesian Analysis accepted a response to an article by Pratola that Dr.  Abdolreza Mohammadi and Dr. Maurits Kaptein wrote. Find our response here. We are quite happy being featured in BA, and I can really recommend the original article; this can be found at: https://projecteuclid.org/euclid.ba/1457383101.
  2. Methodology accepted a paper by Lianne Ippel, Maurits Kaptein, and Jeroen Vermunt on dealing with data streams. Its a very interesting tutorial on scaling up (traditional) analysis methods to deal with data streams. Find the manuscript here.
  3. Finally, a cool paper on Personalized Product Recommendations by Essi Poyry, Juho Hamari, Petri Parvinen, Hietaniemi Hinni and Maurits Kaptein was accepted for presentation at the HICSS 2017 conference. Please find an early version here.

That’s it for updates on publishing (although a very cool paper using LiFt was rejected as well last month — a pre-print can be found here: https://arxiv.org/abs/1607.08108).

Also, there was some coverage of the best paper that Jorrit Siebelink, Peter van der Putten, and Maurits Kaptein wrote for Intetain. See it here:  http://blog.eai.eu/understanding-cognitive-biases-through-virtual-role-playing/

Finally, note that JADS has officially started! (www.jads.nl). We hope to see you all soon in Den Bosch where we are working on a bunch of new research projects! And, please do join us for http://www.jads.nl/big-data–dance.html.



New submission to arXiv

Hi all,

We just posted a new paper on arXiv; its a cool combination of Lock-in Feedback, and the beauty of avatars. The abstract reads:

“Lock-in feedback circuits are routinely used in physics laboratories all around the world to extract small signals out of a noisy environment. In a recent paper (M. Kaptein, R. van Emden, and D. Iannuzzi, paper under review), we have shown that one can adapt the algorithm exploited in those circuits to gain insight in behavioral economics. In this paper, we extend this concept to a very subjective socio-philosophical concept: the concept of beauty. We run an experiment on 7414 volunteers, asking them to express their opinion on the physical features of an avatar. Each participant was prompted with an image whose features were adjusted sequentially via a lock-in feedback algorithm driven by the opinion expressed by the previous participants. Our results show that the method allows one to identify the most attractive features of the avatar.”

Give it a try here: https://arxiv.org/abs/1607.08108



ps. It might be quite over summer / August, we will post more in September.

Best paper at intetain.

Jorrit just won the best paper award at Intetain; pretty awesome!image

New paper accepted!

I am happy to announce that Lianne Ippel her paper (in joint work with Maurits Kaptein & Jeroen Vermunt) called “Estimating Random-Intercept Models on Data Streams” is accepted for publication in Computational Statistics and Data Analysis (CSDA). This is awesome!

You can find an author copy of the paper here.


Abstract accepted


I am happy to share that Prof. Davide Iannuzzi will be presenting some of the joint work that Robin van Emden, me (Maurits Kaptein) and Davide have been doing together at APEC-SSS 2016. The abstract can be downloaded here.


Maurits (by the way, currently I am at the ISBA conference which is great!)


Hi All,

A few updates: First, things are going extremely smoothly at JADS where we are setting up a new Data Science research institute. We are happy to be a part of it, and to be collaborating with some great minds (such as Prof. Dr. Eric Postma). Also, we will be sharing new work on StreamingBandit during the Social Sciences and the Internet Conference (check here, and here is an abstract of the talk). Finally, we will be presenting a poster at the ISBA 2016 conference. Check out the poster here.

We also have some cool recent work that I would like to share. First, Robin van Emden did a pretty cool visualization of how Lock in Feedback (LiFt) works in two dimensions; (not that LiFt is implemented as a policy in StreamingBandit). Check this out:

LiFT animation I from Robin van Emden on Vimeo.


We think its pretty cool!

Also, up and coming, some really cool work by Shuai on distributing media expenditure over different channels, and some really cool stuff by Jules implementing a) simulation functionality into StreamingBandit, and b) creating an offline evaluation methods for continuum bandit problems.


Paper and projects

Hi all,

Just a brief update: A paper written by Jorrit Siebelink, Peter van den Putten, and Maurits Kaptein was recently accepted at INTETAIN 2016 which is coming up soon. Grab an author copy here.

Furthermore, we are doing some very cool project with 2 Finish companies on (1) optimizing media spending dynamically – together with Prof. Dr. Petri Parvinen – and (2) optimizing rebate offers. Both are exciting, and both use the StreamingBandit back-end. We will share results as they come available. We here also have some awesome work by a new student contributing: Shuai Yuan.

Finally, we would like to alert to JADS, the new and exciting joint data science initiative by the TU/e Eindhoven and UvT Tilburg. Maurits will be one of the staff member of JADS in years to come.

Guess that’s it for now; hope to have more updates on papers and recent work in the coming weeks.

Update; Persuasive 2016 + book

Hi All,

Finally, our book is out!

And, I (Maurits), just yesterday gave the closing keynote for the workshop on Personalization (see here). It was a great session. My slides are available here.

Currently Persuasive 2016 is on its way, and, thanks to the organizers, its a great event! Check out the program here.

Finally, note that the publication page was updated. Check it here.

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