Workshop on sustainable entrepreneurship

Participated in two-day a workshop offered by the Graduate School of TU Delft, and took place at the Yes!Delft incubator. Topics included business model generation, business canvas, team-building challenges, lean startup, success/failure stories, etc. Participants (all doctoral students at the TU Delft) were divided into teams of 4, and each team had to pick one of the research topics of the group members to try and turn it into a business idea.

Our team picked a topic that was quite far from what I do: building vegetation (the vertical type that can be attached to the outside of a house or a building), that saves energy, prolongs the life of the building, provides better isolation (and thus reduces energy costs) and cleans the air from certain harmful material.

It was quite interesting that, despite the fact the remaining team members had no experience on the topic, we were able to contribute quite well to the business model/canvas, gaining traction, and ideas for generating profit. See photos below! (Full of post-its).

IMAG0066 IMAG0063 IMAG0065


Mixed models with nested random effects in R

Once again, SPSS failed me miserably while trying to run my mixed, multilevel model below:

nested model

The first two levels, BSO(i.e. day care center) and pp (participant) are nested random effects. As the model shows, each participant’s “emotional” or behavioral code (e.g. engaged, excited, bored, …) was sampled several times, during two sessions (once for each of the app’s two versions). SPSS failed to allow me to build this model properly, mostly failing to comprehend that random effects have more than one level.

So I turned to R and found several, very interesting (though maybe a bit long to read) tutorials using the package lme4, so credit goes to Bodo and Ben for their extensive effort into simplifying what could be a very complex process.

The way it worked for me is below, described in an overly simplified way.

require(xlsx) #to read excel sheets
require(lme4) #the package
Behavioral <- read.xlsx("behavioral", 1) #the data set

#certain things we need to ensure are treated as factors
#default is covariants
Behavioral$version = as.factor(Behavioral$version)
Behavioral$pp = as.factor(Behavioral$pp)

#first we construct the null model
#emotion type as response with no fixed factors
#and a nested BSO and pp as random factors
model.null <-lmer(emo.type ~ 1 + 1|BSO/pp, data = Behavioral, REML=FALSE)

#we then construct our model, adding version as fixed factor
model <-lmer(emo.type ~ version + 1|BSO/pp, data = Behavioral, REML=FALSE)

#see summaries of the models here
summary (model.null)
summary (model)

#to obtain the p-value, i.e. to see if adding
#the fixed factor made a significant difference

#and finally
#will generate a bibtex entry so you cite the authors of the package!

Journal article: “A social commitment model for location sharing applications in the family domain”.

Just submitted a journal article titled “A social commitment model for location sharing applications in the family domain”, to the International Journal of Human Computer Studies (IJHCS). In this article I discuss the creation of the social commitment model and lifecycle (see photo below), throughout the conception phase, evaluation through CCS, then the enhancement, creation of an alternative lifecycle, and then evaluation results using SWT.

Will update this post with a preliminary version once it’s been published. If you would like a copy already, leave a comment with your email.


Gave a talk at Social Media Week Rotterdam, 2015!

Was very glad this week to have given a talk @Social Media Week conference in Rotterdam! This event is a part of an international Social Media Week, which takes place in different cities simultaneously around the globe, on 4 different occasions every year (Rotterdam was during the same week as London, Miami, and Sao Paolo). I talked about the results of two experiments, the usability/usefulness study conducted using the crowd sourcing platform, and the app testing at the day care centers with children.

I was at the main room (zaal 1), and the talk was streamed live online and was archived as well. You can check it out below. Great experience overall, looking forward for coming back next year as well!

Critical Alternatives 2015 conference, Aarhus, Denmark.

Just back from Aarhus (and a weekend in Copenhagen), it was the 2nd time I visit Denmark. I attended the Critical Alternatives conference, 2015 edition. This conference is special in two ways: first, it is held once every 10 years! And second, the type of work presented there is quite novel, visionary, and out of the box.

On Monday I participated in the Charting the next decades for VSD workshop. There was a short, 2-minute presentation for everyone as an introductory round in the morning, and afterward the workshop took the shape of workgroups of 4-5 people and a presentation afterwards. Discussions during the workshop were very insightful.

The Conference on Wednesday/Thursday had plenty of interesting talks, including the keynote by Telekommunisten, the talks in the session on privacy, and the discussion with Frider Nake for example. Notably, the conference dinner took place in the old Aarhus train station turned industrial space. Very artistic place to say the least. See photos of the conference below!

aarhus 2015 (60)

Paper accepted to Value-Sensitive Design workshop!

Got my paper “Effects of conflict resolution strategies in normative frameworks on user values: a proposed study” accepted at the Charting the Next Decade for Value-Sensitive Design workshop , which is going to be held in conjunction with the decennial conference on Critical Alternatives 2015 in Aarhus, Denmark. You can get the accepted paper here.

It will be very interesting to meet the VSD (value-sensitive design) enthusiasts from all over the world, especially from the University of Washington where it all originated more than 20 years ago. I will also be looking forward towards the feedback that I will get on my proposed conflict resolution user study.