Ming_Ki Chong

this is my unexpected online exception

Ming_Ki Chong
Quick question: the chicken or the egg?
Answer: roast the chicken and scramble the egg, and there is a delicious meal. ─=≡Σ((( つ◕ᴗ◕)つfly away …


  "first_name"    : "Ming_Ki",
  "last_name"     : "Chong",
  "also_known_as" : "the guy with an _underscore",
  "who_am_i"      : ["software engineer", "researcher", "mentor", "leader"],
  "motto"         : "simplicity",
  "email"         : "hellomingkichong•net",
  "superpowers"   : ["transforming carbohydrates into computer code",
                     "creating and fixing unexpected exceptions",
                     "confusing people by asking (too) many questions"],
  "uniqueness"    : "being weird",
  "languages"     : ["English", "Chinese (Cantonese)",
                     "whatever programming languages that you can throw at me"]
I am an unexpected exception that just happened to happen
Feel to POST me a message
Please don't DELETE my reply
Also, don't PUT my response in the spam box
If something is wrong, let's PATCH things
I hope you GET my message
By the way, if I don't reply immediately, I might just be REST-ing, and I will eventually be consistent and respond

About Ming_Ki

My Name

My full name is "Ming Ki Chong" (pronouns he/him/his). "Ming Ki" is my first name (it's a double-barrelled name), and "Chong" is my surname. You are welcome to address me by my first name. Stay casual, no need to be formal (◕‿-).

My Philosophy

I believe in simplicity, "less is morea.k.a. minimalism", and “everything should be made as simple as possible, but no simpler”. Also, no matter how sophisticated a concept is, if it is not solving a problem, it is unuseful.
My philosophy is "users first" and decisions should be made based on facts, not assumptions. Team members should be able to think freely, and everyone in a team has an equal voice.
I embrace the supportive leadership style. I influence others through persuation, not manipulation. And, I strongly believe in growing juniors and empowering peers to force multiply.
I appreciate constructive criticisms. I welcome everyone to challenge my ideas, believes, and decisions.
I mentor by guiding and challenging people to think differently, as well as outside the boxbut what if the box contains Schrödinger's cat ( + + ) ?. We are all familiar with the old saying of "Give a man a fish, and you feed him for a day. Teach a man to fish, and you feed him for a lifetime." I believe we should push it a step further. Ask the man what different tools he can make or use to get more fish. So, guide a man to think of fishing differently, and you feed him, his family, and his village, for as long as they like fish. reverse fishing
New ideas start with breaking free from conventional thinking.

My Interests

  • Building APIs and useful technology that solve problems
  • Designing system architectures and making them scalable
  • Understanding requirements of users and solving their needs
  • Mentoring juniors and celebrating their successes
  • Learning new technology (or anything, for that matter)

My Brief History

Currently, I am working as a senior software engineer @ Ironclad, Inc., an innovative contract lifecycle management software company in San Francisco, CA.
I spent a few years in the Netherlands. I was working as a team lead and a backend software engineer in Booking.com. I have years of experience of building APIs (RESTful services) and optimising system architecture for high volume of traffic. In Booking.com, I was part of the team (which I also led) that implemented and successfully launched Content API. The API is a direct channel for content managers to build and maintain properties on Booking.com via HTTP calls. The team also refactored a huge monolith into smaller modules for migration to microservices.
I also implemented the Brotli compression feature for Booking.com's frontend web traffic . Results of the A/B tests showed that the feature is over 10% more data efficient than gzip. The improved compression enables quicker delivery of Booking.com's web content to end users.
Prior to working in the industry, I was an academic researcher in University of Glasgow and Lancaster University in the UK.

My Research Interests

I have special interests in user-centered design and creating technology that is easy to use. My expertise is in qualitative user research. I have a PhD in Computer Science with a specialisation in understanding users' needs and requirements.
My research interests are in the cross section of Mobile Computing, Human-Computer Interaction (HCI), Ubiquitous Computing, and Usable Security. I investigated topics of
  • connecting wireless devices
  • multimodal interaction (gaze, touch, gesture)
  • mobile authentication
  • interventions for work-life balance
Feel free to have a look at my past projects and my publications, or reach out to me directly if you are interested in any of the topics.

My Skills & Strengths

Excellent skills in Communication, Team Management, and Leadership
Strong problem analysing and solving skills
Passion for creating amazing user experiences (PhD in understanding user requirements)
Self-starter with experience working in agile environments and dynamic teams
Building easy-to-use APIs and RESTful services and writing technical documentation
Strong knowledge in optimising and scaling system architectures
Providing mentorship and guidance to juniors and guiding them to think differently
Proficient in Git; Java; TypeScript; Perl; C#; SQL; PHP; HTML/CSS/JS; XML; Android; Flutter and Dart;

My Past Projects

MyLifeRocket is a project that focused on life-style habits and well-being. It is a web-based self-tracking platform for people to report their behaviour/thought/mood. It incorporates social networking features which allow friends to join experiments, as well as share and discuss their experience.
Below is a short demo:
SqueezeDiary is a mobile app that literally allows users to squeeze the moment (source). A user enter a diary event by squeezing a sensor ball. The squeeze action triggers the system to record the timestamp, the location, and the pressue as a diary instance. The user can later review and reflect on the stored instances, as well as add additional information. In parallel, I also created a mobile text diary for comparison (source).
The SqueezeDiary app was showcased in multiple international conferences. The research study result was published in INTERACT 2015.
GesturePIN (Gesture Password) consists of 10 distinct gestures. It is a new interface for users to enter their PIN. The concept is to replace PIN digits with gestures, especially for mobile devices that are too small to have a user interface for PIN entry. The research explored the possibility of using muscle memory for password retention, instead of memorising text.
Where's It is a simple mobile app (source) that allows users to record their current location by a push of a button. The users can later review the location on a map and navigate back to the location.
Get it on Google Play
My Location Address is built with Flutter (source). It retrieves the address of the user's location.
Get it on Google Play
How Users Connect Devices was part of my PhD user research project. It examined the rationale and the types of actions that people would come up with when they connect devices on the spot. It turns out that quite a few factors (like mobility, physicality) can influence their choices.



  • Look together: using gaze for assisting co-located collaborative search

    Yanxia Zhang, Ken Pfeuffer, Ming Ki Chong, Jason Alexander, Andreas Bulling, Hans Gellersen
    Personal and Ubiquitous Computing. 21(1): 173--186 (2017)

  • Connecting devices for collaborative interactions

    Tero Jokela, Ming Ki Chong, Andrés Lucero, Hans Gellersen
    Interactions. 22(4): 39--43 (2015)

  • Select & Apply: understanding how users act upon objects across devices

    Adalberto Lafcadio Simeone, Ming Ki Chong, Corina Sas, Hans Gellersen
    Personal and Ubiquitous Computing. 19(5-6): 881--896 (2015)

  • Eye tracking for public displays in the wild

    Yanxia Zhang, Ming Ki Chong, Jörg Müller, Andreas Bulling, Hans Gellersen
    Personal and Ubiquitous Computing. 19(5-6): 967--981 (2015)

  • A Survey of User Interaction for Spontaneous Device Association

    Ming Ki Chong, Rene Mayrhofer, Hans Gellersen
    ACM Comput. Surv.. 47(1): 8:1--8:40 (2014)

  • Usability classification for spontaneous device association

    Ming Ki Chong, Hans Gellersen
    Personal and Ubiquitous Computing. 16(1): 77--89 (2012)


  • Cue Now, Reflect Later: A Study of Delayed Reflection of Diary Events

    Ming Ki Chong, Jon Whittle, Umar Rashid, Chee Siang Ang
    In Human-Computer Interaction - INTERACT 2015 - 15th IFIP TC 13 International Conference, Bamberg, Germany, September 14-18, 2015, Proceedings, Part III. Pages 367--375.

  • Gaze-Shifting: Direct-Indirect Input with Pen and Touch Modulated by Gaze

    Ken Pfeuffer, Jason Alexander, Ming Ki Chong, Yanxia Zhang, Hans Gellersen
    In Proceedings of the 28th Annual ACM Symposium on User Interface Software & Technology, UIST 2015, Charlotte, NC, USA, November 8-11, 2015. Pages 373--383.

  • GazeHorizon: enabling passers-by to interact with public displays by gaze

    Yanxia Zhang, Jörg Müller, Ming Ki Chong, Andreas Bulling, Hans Gellersen
    In The 2014 ACM Conference on Ubiquitous Computing, UbiComp '14, Seattle, WA, USA, September 13-17, 2014. Pages 559--563.

  • Gaze-touch: combining gaze with multi-touch for interaction on the same surface

    Ken Pfeuffer, Jason Alexander, Ming Ki Chong, Hans Gellersen
    In The 27th Annual ACM Symposium on User Interface Software and Technology, UIST '14, Honolulu, HI, USA, October 5-8, 2014. Pages 509--518.

  • How groups of users associate wireless devices

    Ming Ki Chong, Hans-Werner Gellersen
    In 2013 ACM SIGCHI Conference on Human Factors in Computing Systems, CHI '13, Paris, France, April 27 - May 2, 2013. Pages 1559--1568.

  • How users associate wireless devices

    Ming Ki Chong, Hans Gellersen
    In Proceedings of the International Conference on Human Factors in Computing Systems, CHI 2011, Vancouver, BC, Canada, May 7-12, 2011. Pages 1909--1918.

  • GesturePIN: using discrete gestures for associating mobile devices

    Ming Ki Chong, Gary Marsden, Hans Gellersen
    In Proceedings of the 12th Conference on Human-Computer Interaction with Mobile Devices and Services, Mobile HCI 2010, Lisbon, Portugal, September 7-10, 2010. Pages 261--264.

  • HandsDown: hand-contour-based user identification for interactive surfaces

    Dominik Schmidt, Ming Ki Chong, Hans Gellersen
    In Proceedings of the 6th Nordic Conference on Human-Computer Interaction 2010, Reykjavik, Iceland, October 16-20, 2010. Pages 432--441.

  • IdLenses: dynamic personal areas on shared surfaces

    Dominik Schmidt, Ming Ki Chong, Hans Gellersen
    In ACM International Conference on Interactive Tabletops and Surfaces, ITS 2010, Saarbrücken, Germany, November 7-10, 2010. Pages 131--134.

  • Exploring the Use of Discrete Gestures for Authentication

    Ming Ki Chong, Gary Marsden
    In Human-Computer Interaction - INTERACT 2009, 12th IFIP TC 13 International Conference, Uppsala, Sweden, August 24-28, 2009, Proceedings, Part II. Pages 205--213.


  • Understanding Spontaneous Device Association

    Ming Ki Chong
    PhD Thesis (Supervisor: Hans Gellersen), Lancaster University, 2013. 150 Pages.

  • Usable Authentication for Mobile Banking

    Ming Ki Chong
    MSc Thesis (Supervisor: Gary Marsden *), University of Cape Town, 2009. 155 Pages.
    * In memory of Gary Marsden

Academic Volunteering

2021 • Ming_Ki Chong • Last updated: February 2021