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STEFAN ZHELYAZKOV

Software Engineer

Bachelor of Science in Engineering with Computer Science, UPenn 2013.

Stefan Zhelyazkov University of Pennsylvania Stara Zagora, Bulgaria stefan.zhelyazkov@gmail.com github.com/stefan-zh linkedin.com/in/stefanzh

Employment

Associate Software Architect

2022 - now
Musala Soft, Bulgaria

Lead Software Engineer

2021 - 2022

Senior Software Engineer

2020 - 2021

- Working on an enterprise solution at SAP Labs Bulgaria for a system that stores and validates trust for collections of artifacts using cryptography.

- Managing the team behind the international programming competition CodeIT: https://codeit.bg/eng.

- Participating in the recruiting efforts of the company.

Software Engineer

2018 - 2019
WeWork, New York, NY

- Worked on an application for the furniture inventory of the company. I used Kotlin, Spring, Hibernate, REST, React, TypeScript. I was responsible for the backend architecture, database management, REST API, soft delete infrastructure, speed optimizations, security, tests.

- Initiated a library for DAO objects which makes communicating with the database easier, including working with transactions. The library was shared with other internal teams and received good feedback which helped for its integration in the common backend libraries of the department.

- Worked with a summer intern whose project was successfully integrated into production

Software Engineer

2016 - 2018
Honest Buildings, New York, NY

- Developed most of the first Reporting & Exporting tool - complex and efficient DB queries, in-screen data formatting, coloring, highlighting, filtering, saving, and exporting to Excel. I used Java 8, Dropwizard, AngularJS 1.6, JavaScript, jOOQ.

- Actively contributed to a stronger backend architecture. Initiated and contributed to the separation of the services layer from the endpoints.

- Refactored and cleaned legacy code, resolved bugs and helped increase code coverage.

- Helped introduce a Java linter and a stylechecker

- Regularly updated some of our major BE library dependencies and performed code uplifting accordingly

Technology Analyst

2013 - 2016
Goldman Sachs, New York, NY

Worked on business applications for the Credit Risk team:

- Java back-end applications aggregating GB's of data and producing Credit Risk metrics. Worked on the full flow from sourcing, transforming, aggregating, displaying and storing the data. Optimized the legacy codebase. Documented it. Sped up certain processes by up to 14%.

- Adapted several large Java applications (60GB RAM ~ 120GB) to run on a new grid of servers thus helping reduce maintenance costs. This work resulted in annual savings between $100,000 - $200,000.

- Actively worked with interns and other junior people. Participated in the recruiting efforts of the company, including the firmwide Hackathon Recruiting Committee for 2015/2016.

Education

University of Pennsylvania

2009 - 2013
Bachelor of Science in Engineering Cum Laude

Graduated with a Bachelor of Science in Engineering degree in Computer Science in May 2013. Minors in Mathematics and Science, Technology & Society.

Romain Rolland FLS

2004 - 2009
Stara Zagora, Bulgaria

Graduated from Romain Rolland Foreign Language School. Areas of concetration: English, German, Mathematics and Literature.

Programming Languages

Java/Java 8+

Kotlin

Go

JavaScript/TS

PHP + MySQL

Haskell, OCaml

C/C++, Python

Tools & Technologies

Spring

Dropwizard

React

AngularJS

Docker

JUnit 4/5

jOOQ

Mockito

Git/SVN

Gradle/Maven

Speaks

Bulgarian

English

German

RPi4 Tablet 2 thumbnail

RPi4 Tablet 2

Hardware
The power of JWT and cryptography thumbnail

The power of JWT and cryptography

Video
RPi4 Tablet thumbnail

RPi4 Tablet

Hardware
listcerts.com website thumbnail

listcerts.com

Website
IPCC video thumbnail

IPCC Sixth Assessment Report in Bulgarian

Video
The Voice of Bulgaria 2020 on YouTube thumbnail

The Voice of Bulgaria 2020 on YouTube

Website
Can & Sanem video thumbnail

Can & Sanem

Video
beeTV Plus Android app

beeTV Plus

Mobile
Future Cities

World 2037

Website
Reading Music From Images paper thumbnail

Reading Music From Images

Course Project
wxReversi game thumbnail

wxReversi

Course Project
JamSesh project thumbnail

JamSesh

Website
Lia application thumbnail

Lia

Course Project
WineSquare website thumbnail

WineSquare

Website
Superscalar Processor project thumbnail

Superscalar Processor

Course Project
Lemonlime project thumbnail

Lemonlime

Website
MixMaster app thumbnail

MixMaster

Mobile
MyTube app thumbnail

MyTube

Course Project
PennOS project thumbnail

PennOS

Course Project
Social Plus app thumbnail

Social+

Mobile
OAT Compiler project thumbnail

OAT Compiler

Course Project
PennQuiz app thumbnail

PennQuiz

Course Project
PyPlay app thumbnail

PyPlay

Course Project
Biblioteka app thumbnail

Biblioteka

Mobile
Breakout game thumbnail

Breakout

Course Project
SpaceInvaders game thumbnail

SpaceInvaders

Course Project

Certificates

Building Cloud Services with the Java Spring Framework Oct 2019

Vanderbilt University
Credential ID QUJF6REB8VK3

Kotlin for Java Developers Dec 2018

JetBrains
Credential ID RLG8JJ6C5N5M

Front-End Web Development with React Nov 2018

The Hong Kong University of Science and Technology
Credential ID WERHEH5WYVUD

Algorithms: Design and Analysis, Part 2 May 2015

Stanford University

Algorithms: Design and Analysis, Part 1 Dec 2014

Stanford University

Functional Programming Principles in Scala Jun 2014

École Polytechnique Fédérale de Lausanne

Papers

Authors

Reading Music From Images 2013

Department of Computer Science, University of Pennsylvania

From a historical perspective, there have been many scientific attempts to find a relationship between images and music with respect to the emotions that both subjects evoke. In modern times, these scientific efforts have been facilitated by the use of computers aiming to discover evidence for objective correspondence between visual and audible information. Based on existing research, this research is targeted to analyze currently used algorithms for reading music from images by comparing their output based on feedback from a pool of testers. The second goal is to provide an improved algorithm for conversion of images into music that will extend on the algorithms analyzed in the experiments. This is a process that uses the results of two existing algorithms in the design of a third algorithm, Extended Chromatic Analysis.

Stefan Zhelyazkov

Eric O'Brien

David McDowell

Boon Thau Loo (Advisor)

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Статистически анализ на шампионатните отличия на българските футболни отбори 2013

Individual

Настоящето изследване разглежда националните отличия на българските футболни отбори в родното първенство. Главните категории на статистическия анализ са брой отличия от официални и неофициални турнири, класифициране на трофеите, които се считат за Национална купа, разпределение на клубните отличия по градове, анализиране на коефициента на успеваемост на българските отбори, подробен анализ на успеваемостта на "ПФК Левски (София)", "ПФК ЦСКА (София)" и "ПФК Лудогорец (Разград)" и последно - анализ на дубълите и требълите на българските футболни отбори. Статистическите данни са изложени в раздел "Статистика". Преди това е представена кратка история на българския футбол, обяснения по официалните трофейни турнири и пълен списък на 26-те отбора, които са печелили национални отличия. Изследването завършва със секция, която обобщава резултатите, и представя няколко интересни факта. Изследването не е рецензирано и е отворено за дискусии и по-нататъшни корекции и надграждания.

Stefan Zhelyazkov

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