Serafeim Papastefanos
Verified Expert in Engineering
Full-stack Developer
Athens, Central Athens, Greece
Toptal member since July 27, 2020
Serafeim is a software engineer with over a decade of professional experience and a Ph.D. in electrical and computer engineering. Serafeim is systematic and methodical with a lot of enthusiasm (and patience) when solving interesting, complex problems. His areas of expertise are with C, Java, Python, JavaScript, and a variety of frameworks (Django), libraries (jQuery), and platforms (Android, Linux RHEL/CentOS).
Portfolio
Experience
Availability
Preferred Environment
Slack, Vim Text Editor, Visual Studio Code (VS Code), Linux, Windows
The most amazing...
...thing I've implemented was for my Ph.D. which was a complete system (algorithms and implementation) for fast direct video indexing and searching.
Work Experience
Senior Full-stack Developer
Hellenic Coast Guard
- Introduced Django to the organization and implemented many internal apps for various needs of the organization's users, including warehouse, ship, and vehicle management.
- Implemented the Greek Ministry of Shipping web portal, a parent organization of the coast guard called Ynanp.gr. I used Wagtail, Django, and Python.
- Developed a complete application to manage boat-driver licensing for Greece, both public-facing and back-end implementation. The public site is adeies.hcg.gr.
- Architected a complete application that allows the candidate students for the Merchant Marine Academies to submit their applications electronically. Created the full back end for managing these applications. The public site is eisaen.hcg.gr.
- Implemented a complete solution for passenger ship companies to submit their ship's passenger data in compliance with EU laws. The public site is Isktheea.hcg.gr.
- Supported various legacy systems of the organization.
- Implemented the Hellenic Coastguard web portal using Wagtail, Django, and Python.
- Implemented a complex CRUD internal application using Elixir and Phoenix. The app supports multiple departments, each with different users properly authorized.
- Implemented a Phoenix Liveview app for real-time exams of lifeguard candidates. People login with their profiles and see random questions. They answer in real-time, and after the time limit expires, they see if they have passed the exams.
Software Engineer
Freelance
- Developed the back end and most of the front end of an application with children's activities in Athens, Littlecityspots.com/el.
- Developed the back end for a reverse-classifieds app. (Askprice.herokuapp.com).
- Developed an Android app for displaying vehicle positions on a map; a fleet management company used it to display each client's fleet.
- Initiated the development of an Android app for fleet management. The Google Play URL is Play.google.com/store/apps/details?id=com.m2massociates.tracker.beta&hl=en.
Full-stack Developer
University of Washington - Main
- Upgraded the Liveratlas.org project to the latest version of Python and Django. Changed all dependencies to their latest versions and used alternatives for unsupported packages. Fixed problems that were introduced because of the upgrade.
- Changed the hosting server of liveratlas.org from Centos to Almalinux (RHEL compatible). Upgraded all the components of liveratlas.org, like the Apache Solr that was used for searching to the latest version and PostgreSQL.
- Implemented some small improvements to the Liver Atlas functionality. These features were implemented in Python and Django, as well as JavaScript and jQuery.
Full-stack Developer
Decent Studios
- Created a (prototype) real-time multiplayer game using Phoenix Live View. The players were moving in a maze and could do various actions depending on where they stood to extract resources from the maze. Any number of players could join.
- Developed a prototype real-time single-player game using Phoenix Live View. The player displays a list of choices, and based on each choice, he could change the state of the world. This was a text-only game.
- Implemented a Phoenix LiveView app for auto-generating complex images by combining some parts. Designers could design their images, save them, etc.
Appian Software Enginner
Exus | Piraeus Bank
- Worked in a team that installed and configured Appian BPMS in production in Piraeus bank using JBoss for deployment; was also responsible for Appian and JBoss server's health.
- Implemented a number of complex BPM workflows in Appian. Among them were the basic user synchronization workflow between Appian and the bank's HR system and a state-inducted loan origination process.
- Wrote a number of smart nodes (add-ons) for Appian to integrate with the bank's web services, e.g., integrations with the CRS system, the DMS, the reporting tools, and so on.
Experience
Little City Spots
I developed this project's back end and some things from the front-end.
AskPrice
I implemented the whole back end along with all the server administration work needed to run the app in production. The project isn't active anymore, but I have uploaded it to Heroku to offer a demo.
Boat Driver Permission System
https://adeies.hcg.gr/I handled all the development for this web application using Django.
Everygate Tracker
FoodRec
Education
Ph.D. in Electrical and Computer Engineering
National Technical University Of Athens - Athens, Greece
Master's Degree in Electrical and Computer Engineering
National Technical University Of Athens - Athens, Greece
Skills
Libraries/APIs
jQuery, REST APIs, React, FFmpeg
Tools
Vim Text Editor, Slack, Apache Solr, Servlet
Languages
Python, Java, C, Elixir, JavaScript, HTML, SQL, PHP, CSS, C#, C++, Ada, Lisp, XML, Fortran, Prolog, Pascal, Python 3
Frameworks
Django, Spring, Phoenix, Tailwind CSS, Bootstrap
Paradigms
REST
Platforms
Android, Linux RHEL/CentOS, Appian, Windows, Linux, Debian Linux, JBoss, WebSphere, Visual Studio Code (VS Code)
Storage
PostgreSQL, MySQL, IBM Db2
Other
Architecture, Web Scraping, APIs, Back-end, SOAP, Phoenix LiveView, Fly.io, Wagtail CMS, Ubuntu Server, RHEL, Software Engineering, MPEG, Videos, H264, Web Servers, Algebra, Calculus, Differential Privacy, Complex Networks, Networking, Administration
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