Ken Roe, Mobile Developer in Vienna, Austria
Ken Roe

Mobile Developer in Vienna, Austria

Member since October 21, 2014
Ken is a highly skilled mobile app developer and software engineer with over twenty years of experience. He has been running a small company that develops and sells mobile apps, and he is especially good at Python, Objective-C, Android, and Swift. He holds a Ph.D. in computer science from Johns Hopkins University.
Ken is now available for hire




Vienna, Austria



Preferred Environment

Android Studio, Vi, Xcode

The most amazing...

...product I've developed is an iOS app, Smart Recorder, which has been installed on over a million iOS devices.


  • CEO

    2009 - PRESENT
    Roe Mobile Development
    • Developed and published an audio recorder app (Smart Recorder for iOS) from scratch. Smart Recorder makes extensive use of the various audio APIs in iOS including AudioToolbox and the creation of Audio graphs. The app has 1,000,000 device installs and over 100,000 users. This project gave me experience building and maintaining a commercial quality app.
    • Developed PHP/MySQL code for a transcription service server. This tool accepted RESTful requests from the Smart Recorder app, maintained a database of customer account information, and forwarded requests to the Amazon Mechanical Turks service for processing.
    • Managed the development and publication of an Android port of the Smart Recorder product (over a period of about a year).
    • Developed and published several other iOS apps including Smart Swipe Keyboard, Travel Diary, Transylvania, The Nuclear Test, and Word Quiz.
    • Developed and published a port of Smart Recorder to Windows 8 written in C++ and XAML.
    • Developed and published a port of Smart Recorder for Windows phone using C#, C++, and XAML.
    Technologies: C++, Java, C#, Objective-C, Windows Mobile, Windows, MySQL, PHP, Android, MacOS, iOS
  • Staff Software Engineer

    2019 - 2020
    • Developed Coq framework for proof by reflection. This speed up rewriting operations.
    • Developed methodologies and best practices for completing large proofs in the Coq theorem prover.
    • Developed well founded proof for ProcKami processor.
    • Contributed to the following open source repositories:.
    Technologies: RISC-V, Coq
  • Android Engineer

    2019 - 2019
    RYOT (Verizon, via Toptal)
    • Developed a viewer for H264 video stream.
    Technologies: Kotlin, Java, Unreal Engine, H264, MediaCodec, FFmpeg, NDK, Augmented Reality (AR), Video Streaming, Android
  • Software Engineer/Biomedical Data Scientist

    2016 - 2019
    The Johns Hopkins University
    • Developed a Python script (using Pandas and NumPy) that generates statistical summaries from medical records.
    • Developed two medical web apps using PHP, Bootstrap, and JavaScript.
    • Used machine learning to detect relationships in medical data and to predict the effectiveness of different treatments, mostly using Python and sklearn.
    Technologies: MySQL, JavaScript, PHP, NumPy, Pandas, Scikit-learn, Python
  • Ph.D. Candidate

    2010 - 2018
    Johns Hopkins University
    • Developed a framework within the Coq theorem prover for verifying imperative programs written in a language such as C.
    • Developed a GUI front end (using Python) for developing theorems using the Coq theorem prover.
    • Taught students about Prolog, SAT solvers, and various other constraint solving systems as TA for a declarative methods class.
    • Taught students as TA for an introductory Android class.
    • Developed the IPC 3 iOS app under a contract with the JHU medical center.
    • Developed an educational iOS app for the neurology department.
    Technologies: Prolog, Android, iOS, Python, Machine Learning, Coq
  • iOS/Android Developer

    2015 - 2016
    • Added iOS 9 search support for White Noise 6.0.
    • Fixed a number of bugs required to make the Android release of WhiteNoise 6.0.
    • Added audio to the chatter view in both the iOS and Android White Noise Market apps.
    • Redesigned the settings page in both the iOS and Android White Noise Market apps.
    • Localized both the iOS and Android versions of WhiteNoise.
    Technologies: Android, iOS
  • iOS Developer

    2015 - 2015
    Tickets to the City (via Toptal)
    • Developed an iOS app for scanning ticket barcodes and sending the results to a server.
    Technologies: iOS, AVFoundation
  • Developer

    2015 - 2015
    • Developed a simple PHP/JavaScript website to automatically fill in blanks in hospital consent forms.
    Technologies: PHP, JavaScript
  • iOS Developer

    2015 - 2015
    Salon Swipe (via Toptal)
    • Developed iPhone screens for a redesigned user interface.
    • Fixed critical bugs in audio processing from a credit card swiping device.
    Technologies: iOS
  • iOS Developer

    2014 - 2015
    Zarquon (via Toptal)
    • Refined a custom keyboard layout for iOS.
    • Fleshed out all variants of the keyboard (ASCII, URL, Twitter, etc.).
    • Added iPad layouts.
    • Refined the layout algorithm.
    • Integrated an in-app purchase library.
    • Developed a container app with collection view and search bar.
    • Integrated a library for key pop-ups and tap-and-hold functionality.
    Technologies: Git, Swift
  • Contract Developer

    2014 - 2015
    Spensa Technologies (via Toptal)
    • Developed an iOS app for deploying a network of bug zappers (on a farm).
    • Refined a library for RESTful server communication.
    Technologies: Git, Swift, Core Data, iOS
  • Contractor

    2011 - 2012
    Independent Security Evaluators
    • Ported a key security product from Windows/Linux to Mac.
    Technologies: OpenSSL, MacOS, C
  • Teaching Assistant

    2011 - 2011
    Johns Hopkins University
    • Supervised student Android projects for an Android development course.
    • Gave an occasional lecture during the execution of the course.
    • Held regular office hours to answer student questions.
    Technologies: Java, Android
  • Contractor

    2010 - 2010
    • Developed a low vision version of the talking product.
    • Added many enhancements to improve the performance of the Talking Tag iOS app and integration with Flurry analytics.
    Technologies: iOS
  • Contractor

    2010 - 2010
    Cryptite, LLC
    • Developed a prototype iOS scanner app for color bar codes and tools to encrypt files based on the bar codes.
    Technologies: Libcrypto, OpenCV, iOS
  • MTS 4

    2006 - 2009
    • Developed many sections of documentation for a Common Criteria EAL 4 cert.
    • Fixed many bugs in the Datafort product. This involved FreeBSD Kernel level coding from which I have extensive experience with networking protocols such as CIFS and LDAP as well as C coding.
    • Developed enhancements to the Datafort configuration tools to handle multiple input/output ethernet ports.
    • Developed documentation to help other engineers get up to speed with the Datafort development enviornment.
    Technologies: Wireshark, Virtual Router Redundancy Protocol (VRRP), NFS, FTP, Common Internet File System (CIFS), FreeBSD, C
  • Developer

    2003 - 2006
    • Developed an SMT solver (the heuristic theorem prover) in C. This tool went on to take a second and third place at SMT-Comp'06.
    Technologies: Tcl/Tk, C


  • Smart Recorder

    Smart Recorder is an audio recorder I developed for iOS. It allows both recording and editing and provides a wide variety of features such as auto-pause (temporarily stop recording when the room is silent) and multi-speed playback (with pitch correction).

    Smart Recorder also features a transcription service that converts voice to text.

  • Clinical Profiles

    A Python script that produces statistical summaries of patient medical records.

  • Denim

    Denim – This is a decision support tool that aims to provide an environment in which knowledge engineers and domain experts can convert clinical guidelines into executable rules that generate alerts in the Epic IT framework. This tool is a web app developed with PHP, Bootstrap, MySQL, and JavaScript.

  • Smart Swipe Keyboard

    Smart Swipe keyboard is a custom keyboard for iOS. It allows entry of words by dragging from the first to the last letter and provides the ability to customize the keyboard's colors or to add a background image.

  • Transylvania

    Transylvania is an adventure game. It was originally released on the Apple II in the 1980s. I co-developed a port of this game for iOS.

  • Ipc3

    I developed ipc3, an app for the Johns Hopkins medical center. It gives cancer patients information on treatment options.

  • CoqPIE IDE for Coq and PEDANTIC Static Analysis Model

    CoqPIE is an IDE I developed for the Coq theorem prover. It is available on GitHub at

    PEDANTIC is a Coq framework I am developing to model the behavior of imperative programs.

    Both these projects will form key pieces of my Ph.D. thesis.


  • Languages

    Objective-C, C, HTML5, Python, Tcl, Java, Prolog, C#, ML Programming Language, C++, Coq, Tcl/Tk, Swift, Kotlin, PHP, SQL, JavaScript
  • Libraries/APIs

    jQuery, Tk, Scikit-learn, Pandas, NumPy, OpenSSL, OpenCV, NDK, FFmpeg
  • Paradigms

    App Development, Mobile Development, Functional Programming, Concurrent Programming, RISC-V
  • Platforms

    MacOS, iOS, Android, Windows Mobile, FreeBSD, Linux, Windows, Amazon Web Services (AWS)
  • Other

    CTO, Software Development, Front-end Development, Machine Learning, Libcrypto, Common Internet File System (CIFS), FTP, NFS, Virtual Router Redundancy Protocol (VRRP), Vi, AVFoundation, Video Streaming, Augmented Reality (AR), MediaCodec, H264
  • Tools

    Adobe Photoshop, Adobe Illustrator, Wireshark, Git, Xcode, Android Studio, MATLAB, Android NDK
  • Frameworks

    Core Data, Unreal Engine, Qt
  • Storage



  • Ph.D. in Computer Science
    2010 - 2018
    The Johns Hopkins University - Baltimore, MD
  • Master of Science Degree in Computer Science
    1986 - 1992
    University of Illinois - Urbana-Champaign, IL

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