Honiden Lab

This month, I am based at the Honiden Lab, National Institute of Informatics (NII) in Tokyo. I am very excited to return to NII and continue our collaboration.

This time I will be involved in a large-scale study on mobile app users from different countries. We are aiming to collect data from the top 15 GDP countries – quite ambitious! The study will reveal interesting mobile app usage behaviour in users in different age groups, cultures, and personality types. The data will also be used to construct a realistic simulation of app users in AppEco.


AppEco in ACM SIGEVOlution

My GECCO’12 paper “How to be a successful developer: lessons from the simulation of an app ecosystem” has been featured in the ACM SIGEVOlution newsletter this month. My paper was chosen out of the hundreds of papers in the GECCO’12 proceedings. I am estatic!

Check out the issue here: SIGEVOlution volume 6 issue 1.pdf.

The newsletter cover, see above, features the social network of app users produced by AppEco!

North America

The past few weeks have been hectic. I just presented AppEco at two conferences in North America, GECCO’12 and Alife13. AppEco generated a lot of interest.

Here is how I depict the four types of strategies used by app developers in my GECCO talk:

Several people took photos of my Alife poster (see below), telling me that they know people who would be very interested in my results. I hope the word spreads!

Leadership in Action

Last week, I attended the Leadership in Action course co-organised by UCL, LSE, and SOAS. It was a very intensive three-day course, leaving me exhausted at the end of each day, and totally drained at the end of the course. The organisers call it an “experiential leadership programme.” All 36 participants, who were shortlisted from a pool of early career researchers from UCL, LSE, and SOAS, were given many opportunities to experience leading and being led.

On the first morning, Luke Freeman, the course director, held up a 10 pound note, saying that it is an opportunity, and anyone can take it, but there is only a limited time to do so, and the time will run out very soon. I was sitting at the back of the classroom, furthest away from Luke, and there were rows of people before me. For a split second, I was envying the people sitting right in front of Luke – they didn’t even need to stand up to take the £10 from him, but they were just sitting there. I can see that most of us wanted to take it, but for some reason didn’t, how frustrating! Then I thought to myself, I want the £10 and I am going to go get it. I felt the power of the crowd and my worries about my distance to Luke holding me back, but I steeled my mind and focused on the goal. I stood up, made my way through the rows of people, and claimed my prize. As I was doing that, I felt myself break free from the invisible rule of conforming, and I was just me, focusing on my goal and nothing else. It felt very nice – I felt that people may think I am weird but it is OK. The task wasn’t difficult, but people were holding themselves back. Luke had a lesson for us. Opportunities are everywhere. If we see an opportunity, we should never be afraid to grab them and make the most out of them.

As I was the only one who grabbed the opportunity, I was much talked about after that. Several people came to congratulate me for my “bravery”. They also tried to explain to me why they didn’t stand up soon enough. “I was sitting too far back,” many said. I thought to myself, “so was I…” Another one said, “I was going to get it, but I wasn’t sure if I should, since I am one of the tutors of the course.” I think self-doubt is one’s worst enemy, and it is kind of cool to break free from the crowd.

UCL Bite-Sized Lunchtime Lecture 11th May 2012

I am giving a Bite-Sized Lunchtime Lecture at UCL in May.

Everyone is welcome to attend! Admission is free and details are as follows.

Talk title: How to be a successful app developer

Abstract: It pays to be an app developer. Some of the world’s most recent millionaires made their money from mobile apps. Ethan Nicholas made his million from his iShoot app in less than a year. Rovio, the developer of Angry Birds, made a revenue of $100 million in 2011. With hundreds of thousands of apps in these online stores, what strategy should a developer use to be successful? Should they try many different ideas, make many similar apps, improve on their existing apps or just copy the apps of others? To answer these questions, we created AppEco, an agent- based model of mobile app ecosystems, and use it to simulate Apple’s iOS app ecosystem and investigate the effectiveness of different developer strategies. This talk presents our simulation, results, and lessons learnt.

Time: Friday 11th May 2012, 13:10 – 13:55

Place: Mully’s, UCL Lewis’s Building, Gower Street (map)

Nearest tube: Euston Square

Any questions?  Email me at s.lim@cs.ucl.ac.uk

AppEco in New Scientist

My AppEco work has been featured as lead technology story in New Scientist this week!

The story focuses on our forthcoming paper for GECCO 2012, where we investigate the success of different app developer strategies.

The article is available on the New Scientist website here. I have also included the article below.

GECCO’12: How to be a successful app developer

Over the past few months, I have been very busy developing AppEco, a C++ simulation of mobile app ecosystems. I had a lot of fun with AppEco! It enables me to ask different kinds of “what if” questions about mobile app ecosystems. For example, with so many developers trying out different strategies to increase their downloads, I wanted to know if an innovative developer would receive more downloads compared to a copycat developer.

My collaborator, Peter Bentley (who created the No. 1 best-selling app iStethoscope Pro), and I used AppEco to simulate for popular developer strategies: Innovators, Milkers, Optimisers, and Copycats, and evaluate their performance in terms of number of downloads, app diversity, and adoption rate. We found that Innovators produce diverse apps, but they are hit or miss – some apps will be popular, some will not. Milkers may dwell on average or bad apps as they churn out new variations of the same idea. Optimisers produce diverse apps and tailor their development towards users’ needs. One interesting we did find is that Copycats receive the most downloads on average, but it can only work when there are enough other strategies to copy from. In addition, Copycats can only exist in a minority, otherwise the app store will have many duplicated apps and the ecosystem will suffer. Our paper “How to be a Successful App Developer” has been accepted at GECCO’12.



Copycats are the minority when developers choose their own strategies





*  *  *

AppEco has a lot of potential. In a separate study, we have also used AppEco to study the effects of publicity on app downloads. We simulated different apps, ranging from fabulous to terrible, and applied different publicity strategies to promote the apps. Appearing on the New and Noteworthy Chart is most likely to guarantee downloads. Our simulation shows that with so many apps in the app store, a fabulous app that is not publicised may go unnoticed and consequently receive no downloads at all. We also found that the spike in app downloads after a publicity event resembles a typical epidemic curve. For all the juicy bits, read our paper “App Epidemics: Modelling the Effects of Publicity in a Mobile App Ecosystem.”




The spread of a highly infectious app through the network of users after the app is broadcasted using mass media.