Dimitar Gueorguiev, Developer in Boston, MA, United States
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Dimitar Gueorguiev

Data Science Engineer and Developer

Boston, MA, United States

Toptal member since May 27, 2025

Bio

Dimitar is an engineer and data scientist with over 20 years of experience in optimization algorithm design, mathematical modeling, and software development using object-oriented principles. His expertise includes designing multiprocess and multithreaded applications, numerical methods, performance analysis, and testing. Dimitar also has in-depth experience with parallel processing of large datasets and numerical algorithms.

Portfolio

Nike
Python 3, Kubernetes, PostgreSQL 10, Snowflake, AWS Lambda, Amazon EKS...
Celect
Python 2, NumPy, Pandas, SCIP, Linear Programming, C++14, Gurobi
Qlik
C++14, C#.NET, Bash Script, Amazon EC2, PostgreSQL, Qlik Sense, QlikView

Experience

  • Mathematical Modeling - 20 years
  • Simulations - 20 years
  • Linux - 15 years
  • MacOS - 15 years
  • Python - 15 years
  • PostgreSQL 10 - 9 years
  • C++ - 7 years
  • Python 3 - 6 years

Preferred Environment

Linux, C++, MacOS, Python

The most amazing...

...project has been the fulfillment optimization at Nike, combining reinforcement learning and mixed-integer programming.

Work Experience

Lead Data Scientist and Machine Learning Engineer

2019 - PRESENT
Nike
  • Refactored the existing codebase and reformulated the algorithm as a mixed-integer problem by linearizing the original objective function, resulting in a multifold speedup of the core algorithm.
  • Enhanced Celect machine learning pipelines by adding new features, including a metadata logging service to the database and an entity creation parser.
  • Designed and implemented generative fill algorithms in Python and deployed them in production to post-process and enhance images for Nike marketing campaigns.
Technologies: Python 3, Kubernetes, PostgreSQL 10, Snowflake, AWS Lambda, Amazon EKS, Amazon SageMaker

Senior Data Science Engineer

2019 - 2019
Celect
  • Developed a frequency domain forecaster to predict future trends and seasonal or cyclical patterns in retail and fashion industry datasets.
  • Engineered GCP-based infrastructure to support the deployment of proprietary machine learning frameworks for managing forecasters.
  • Architected proprietary machine learning frameworks, Nabee and Shakun, for assembling and training forecasters on large datasets.
Technologies: Python 2, NumPy, Pandas, SCIP, Linear Programming, C++14, Gurobi

Senior Software Engineer

2015 - 2019
Qlik
  • Built the Qlik Big Data Index (QABDI) engine and passed the prototyping phase. Designed indexing algorithms and managed the movement of column indexlets within the BDI engine to prepare them for efficient consumption by the BDI Query Executor.
  • Architected a centralized logging service to store metrics from the Qlik Engine and other services in a PostgreSQL database.
  • Implemented performance metrics collection for the Qlik Engine and developed processes to export these metrics to the Qlik Repository Service. Instrumented the scheduler to measure Qix Request execution times in a multithreaded environment.
Technologies: C++14, C#.NET, Bash Script, Amazon EC2, PostgreSQL, Qlik Sense, QlikView

Principal Software Engineer

2001 - 2015
Dell EMC
  • Developed WorkloadPlanner, a simulation module integrated into the Unisphere for VMAX software. WorkloadPlanner models target array performance by calculating component utilizations and back-end response times.
  • Engineered TierAdvisor, a performance simulation tool that modeled the impact of Fully Automated Storage Tiering (FAST) on a generic EMC storage system, evaluating disk utilization, response time, and relative cost.
  • Built SymmMerge, a multithreaded performance simulation tool that estimates the performance of EMC Symmetrix storage arrays using supplied configuration data and workload traces, based on a queueing network utilization model.
Technologies: C#.NET, C++, Java 7

Experience

Fulfillment Optimization

I reformulated the algorithm as a mixed-integer problem by linearizing the original objective function, resulting in a multifold speedup of the core algorithm. I redesigned the fulfillment algorithm using the ε-constraint method to replace the weighted objectives method for scalarization. Additionally, I researched various reinforcement learning policy gradient algorithms, such as PPO, to potentially replace the action-value reward-based reinforcement learning component of the algorithm.

Frequency Domain Forecaster

I developed a new frequency domain forecaster that predicts future trends and seasonal or cyclical events in retail and fashion industry datasets. To achieve this, I created a super-resolution algorithm that formulates the problem as a convex optimization task in the frequency domain and solves it using a fast Fourier transform (FFT) relaxation technique.

Collection of Algorithms

https://github.com/dimitarpg13/smooth_gradient_outpaint
I developed a collection of algorithms for smooth gradient outpainting. This unfinished work was created over two months to meet Nike Digital Marketing's need to add outpainting regions with smooth gradient backgrounds to Nike images. These algorithms enable the marketing team to generate a much wider variety of image crops across a large set of aspect ratios. I plan to complete this project in the near future.

EMC Corp Workload Planner

https://github.com/dimitarpg13/personal/blob/main/previous_investigations/ModelforCapacityPlanningandPerformanceEstimationsofDataStorageArray.pdf
I developed WorkloadPlanner, a simulation module integrated into the Unisphere for the VMAX software product. I designed and implemented the component simulation models for central processing units (physical and logical cores), InfiniBand fabric, I/O boards, disks, and I/O ports, all developed and validated in Java. WorkloadPlanner simulates the performance of the target array by calculating component utilizations and back-end response times.

Additionally, I created the WorkloadPlanner FAST model, a constrained optimization solver written in Java. This model determines whether incoming workloads can be accommodated on existing target array pools while respecting performance and capacity constraints. It ensures that storage group SLOs and storage pool SLE response times are not violated and estimates the available headroom on the storage array back end.

Education

1997 - 2001

PhD in Aerospace and Mechanical Engineering

Boston University - Boston, MA, USA

1995 - 1997

Bachelor of Science Degree in Informatics and Applied Mathematics

Technical University of Sofia - Sofia, Bulgaria

Skills

Libraries/APIs

NumPy, Pandas

Tools

Amazon EKS, Amazon SageMaker, SnowSQL, Amazon CloudWatch, Helm, GitHub, Gurobi, MATLAB, Mathematica, Qlik Sense, Google OR-Tools, SCIP

Languages

Python, C#.NET, C++, Java 7, Python 3, Snowflake, Bash Script, C++14, Python 2

Platforms

Linux, MacOS, Kubernetes, AWS Lambda, Amazon EC2, QlikView

Paradigms

Linear Programming

Storage

PostgreSQL 10, PL/SQL, Redis, PostgreSQL

Other

Mathematical Modeling, Simulations, Software Development, Argo CD, Reinforcement Learning, Algorithms, Optimization

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