Roman Petrov

Acroplia is an education, team communication, and collaboration startup.

As a developer, I worked on various parts of the app:
• Implemented and fully covered with unit tests and a robust test passing library in Lua. The back end, iOS app, and Android app use this library.
• Developed the initial version of the test passing front-end code using React and Redux.
• Built a collaborative whiteboard module for the mobile application (Flutter).
• Created a chat module for the mobile app (Flutter).

As a team leader, I had the following responsibilities:
• Led a distributed team of developers (up to ten members).
• Managed project backlog.
• Helped to define project priorities.
• Helped with UX design.
• Participated in meetings with potential customers.

Guitarability was a guitar training application for the iPad. It contained over a thousand exercises on different aspects of guitar playing (rhythm, picking, strumming, legato, scales, bends, and other). Guitarability was a “dream project” for me because I’m a self-taught guitar player and I’m interested in digital signal processing, but I hadn’t had a chance to apply my knowledge of DSP in a commercial project. I managed this project and developed one of the core modules—a performance evaluation module.

The module has two parts: timing analyzer and polyphonic pitch detector. The most challenging one was the pitch detector. The application had to recognize not only single notes but chords too. Polyphonic pitch detection is a difficult task; there’s no “one and only true way” to do it; there are no commercial-grade open-source implementations.

Another challenge was that my module had to work in real-time on the iPad. I managed to get a 600% performance boost compared to the first implementation, which couldn’t even work in real-time. This performance improvement allowed the addition of smooth animations and video recording. I achieved the performance boost mostly by math optimizations.

An iOS application for people learning to shoot a pistol.

I helped to redesign the UI of the application. The redesign focused on improved usability and increased retention rates. I also implemented a timing measurement module for different aspects of pistol shooting (used accelerometer data).

A simple application that helped you to make a decision between multiple variants by assessing them on a number of criteria (a decision matrix).

I redesigned the UI of the app which significantly simplified the process of filling a decision matrix, which increased the app install and retention rate. I also implemented this new design version.

A mobile application for iOS, Android, and Blackberry platforms.

App Features:
• Automatic calls to 911 in case of an emergency like falling or a car crash (used accelerometer to detect such events).
• Notifications about coming natural disasters based on a user's geographic position.

I led the development team and also redesigned the user interface of the app, which increased user retention and install rates.