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I build full data and ML systems that help companies make faster and more accurate decisions. Forecasting models, ETL pipelines, automated reporting and dashboards, and production-ready analytics tools. Commercial experience delivering end-to-end solutions for various companies. I specialize in end-to-end data and ML workflows: forecasting engines, tabular ML models, automated ETL pipelines, and reporting tools that solve real business problems. I focus on clean, reliable, production-ready solutions — not academic prototypes. Core Skills • Python (Pandas, NumPy, Scikit-learn, TensorFlow) • SQL, Snowflake • Power BI, automated reporting • APIs, Git Specialties • Time-series forecasting & predictive modeling • Custom ETL automation (Python + SQL) • Classification models for business decisioning • KPI dashboards & analytics systems Experience & Delivered Work • Connectis – Supporting a large-scale financial compliance project for a major Polish bank in the area of KYC/AML. Responsible for data analysis, system verification, and ensuring process integrity within banking systems. • One of the largest Crypto Wallet – Data Analyst ETL pipelines (Python + Oracle), forecasting engines, Power BI dashboards, and high-volume transaction analytics. • Aesthora – Designed and built a full-face analysis system using ML to detect facial symmetry, ratios, and proportions. Reduced image analysis time by 50% and minimized human input to final audits, boosting efficiency and consistency. Education • Bachelor’s in Computer Science • TensorFlow Developer Certificate • Microsoft PL-300 • Google Data Analytics Professional Certificate I work fast, communicate clearly, and deliver solutions that actually run in production. If you need someone who can take a data/ML problem from idea to working system — I can help.

Since 2002 I have been employed at the Department of Economic Forecasting and Analysis at Wroclaw University of Economics. Currently at the post of an assistant professor. Although this work gives me a lot of satisfaction, I am looking for opportunities to test the suitability of my knowledge and skills (and maybe acquire new) in a real business. My current work is shared more or less equally between scientific research and teaching. In addition, occasionally I do expert analyses. I also own websites www.szandula.pl (a website for communication with students ) and www.wzory.info (portal featuring equations and tables used in different areas of science – as for now in the early stage). Both in my research and teaching work I use a number of different programs and programming languages such as: a) MS Office and Open Office family: Excel, Access, SQL, VBA; b) statistical and econometric software: Statistica, SAS, SPSS, R, OX, GRETL; c) computing environments: Matlab & Simulink, Octave; d) internet oriented: HTML, Webharvest , XPATH , JavaScript , BeanShell; e) graphics programs: Corel Draw, GIMP. RESEARCH The area of my research interests include mainly the theory of forecasting with particular emphasis on analogue methods, and time series analysis. In practical applications I mainly deal with the study of irregular cyclical fluctuations in the micro and macro scale. Earlier, I dealt with the demographic processes . I am the author of over 20 publications. In addition to publication in scientific journals I prepared and made available on my website workbooks using VBA macro for calculating analogue forecasts . TEACHING I hold both lectures, classes and computer labs. Since two years also in English. Up to now, I've been responsible for following courses: fundamentals of quantitative methods, mathematical statistics and econometrics, forecasting theory and computer simulation , forecasting and simulation , financial forecasting , financial analysis. I am the author of a prototype tool for automated checking students' knowledge of different courses. Macros written in VBA generate for each student individual set of exercises as well as their solutions. Student's solution is automatically checked . This system has been used successfully for 7 years in an increasing number of courses. It currently supports : financial analysis , mathematical statistics and econometrics, financial forecasting , fundamentals of quantitative methods. I plan to launch it on e-learning platforms. EXPERT ANALYSIS Occasionally I undertake expert analysis on demand. I have been involved in the preparation of, inter alia: - for the Wrocław City Office: forecasts of the development of different economic sectors in Wroclaw. - For the County Office of Złotoryja: statistical analysis of a survey on labor force participation of people with disabilities in the Złotoryja county. My task was firstly to write software using the language VBA and SQL to automatically obtain statistical measures for the desired queries and secondly to interpret some of the results. - For individuals: statistical studies of various surveys.

I have Expert-Vetted Talent (EVT) badge - it's Upwork's top 1% freelancers — pre-screened by Upwork Talent Managers and experts in their field. Out of ~30 million programmers worldwide, only a few thousand know Algorithms & Data Structures better than I do, which is proven by programming competitions. Please, contact me if you need that skill level (top 0.01%). I can do algorithmic/performance work in C/C++, Python, SQL, Java, MQL4, MQL5, C#, Assembly, JavaScript, Julia, Rust, and probably other languages - learning them rapidly. I also work with AI, mostly in NLP and NLU: large language models including OpenAI GPT-3, Bloom, BloomZ, GPT-J 6B, LLaMA, Alpaca, etc.; HuggingFace Transformers, Accelerate; Petals, Deepspeed, zfp/zfpy; CUDA, CPU, and MPS (AArch 64 M2 MacOS Metal GPU) backends. I have some work experience with Apple Neural Engine (ANE). In AI, I also worked with XGBoost for predictions (including trading), LibSVM, TensorFlow, PyTorch, Scikit-learn, etc. I have the hardware in my home office for training and inference with large language models and other AI. English: C1 (Grammarly plugin says I use more unique words than 95% of other users, native speakers included). Polish: B1 (86%). Russian, Belarusian: Native. - With unique skills in Algorithms & Data Structures, I improve programs asymptotically (often 100 or more times on large input data). - 29 years of programming (started Basic and assembler on ZX Spectrum), 24 years of C/C++, 16 years of commercial work experience + 3 years of research projects. - Contributed to widely used Open Source projects: LLVM/Clang (my contribution is XRay profiler on ARM32 and AArch64 systems), Katana Graph (multiple small contributions mostly driven by the proprietary part where I do GPU/CUDA), CBMC "C Bounds Model Checking" (I contributed parallelized output of DIMACS formatted Boolean Satisfiability formula), oatpp (C++ web framework, I contributed bug-fixes), OWL (OptiX Wrapper Library, I contributed build fixes for Ubuntu), Galois (research project for distributed computations on graphs, I contributed GPU improvements) - Actively participated in bug reporting and reproduction (for NVIDIA CUDA, Cadical&kissat boolean satisfiability solver, JBOSS, MariaDB, Tensorflow, Linux, etc) - Led several open-source projects of my own: ProbQA (a video game recommendation system based on a high-performance Bayesian inference engine with CUDA, SIMD, and multi-threading); InSoAr (automatic reconstruction of software architecture from source code ), a multi-threaded Boolean Satisfiability solver, etc. Working for hire, implemented: - efficient multi-threading, scaling real-world workloads almost linearly with the number of CPU cores (128x for AMD Ryzen Threadripper 3990X) - SIMD vectorization (SSE/AVX), up to 8x improvement in computing thread or even copying (see my "Faster alternatives to memcpy" answer on Stackoverflow, URL upon request). - cache-aware algorithms: up to 50x improvement on some workloads - up to 20 trillion operations/second in CUDA (thousands of times faster than CPU) - up to the theoretical limit (6.8 Gigarays/second on RTX 2080 laptop GPU) in ray-tracing with OWL and OptiX - AVX512 and RTM (Restricted Transactional Memory) based acceleration, 16x improvement for float numbers -up to 20x improvements to cryptocurrency miners on CPU using AVX512 and cache-friendly algorithms - crypto-miners for Ethereum, Bittensor, Qubic 15K reputation on Stackoverflow: (1915854/serge-rogatch) Topcoder SRM score: 1480 - among top 5K programmers in the world - top 0.02% (rSerge) I developed all kinds of networking applications, from Linux Kernel modules up to Web applications. The majority of work was, of course, done at TCP/IP level with socket calls like send/recv/select. Programming languages: C++, C++11/14/17/20, C, Python, x86/x64/ARM/AArch64 assembly, SQL, C# .NET, JavaScript, HTML, CSS, Java, MQL4, MQL5, XML, Cypher, Rust. Libraries/Frameworks: PyTorch, Tensorflow, HuggingFace Transformers/Accelerate/Safetensors, Hivemind/Petals, OpenAI, tiktoken, Django, Flask, STL, LibSVM, XGBoost, libcurl, Selenium, PyTorch, Transformers. Technologies: OpenMP, CUDA, SIMD (AVX&SSE, RTM), Linux Kernel Modules, OptiX/OWL, RTX, raytracing. Theory/Principles/Know-how/Methodologies: Algorithms & Data Structures, Performance Optimization, Artificial Intelligence, Multithreading, Vectorization, OOP, Low-latency, High-frequency, Blockchain. Open source code: Clang, LLVM, LLVM's compiler-rt library, Linux Kernel, a few of my own repositories, contributions to AI and Algorithm open-source projects such as Petals and CBMC. Tools/APIs/Architectures/Platforms: PostgreSQL, MSSQL, MySQL, Neo4j, MATLAB, CMake, GIT, MT4, MetaTrader 5, Conda, PyCharm. Virtual Machines / Containers: Docker, VMWare, VirtualBox, QEmu, Hyper-V. OSes: Windows, Linux, Android, macOS

Applied Mathematics Graduate from Zimbabwe. Obsessed with customer satisfaction and always aiming for perfection.

As a highly skilled data professional with a strong background in mathematics and applied mathematics from Jagiellonian University, I bring over 12 years of experience as an analyst and seven years as a programmer. My expertise lies in data processing and analysis, with a keen interest in automating and streamlining processes. My technical skills include expert-level VBA, R, and Python knowledge, which I use daily. I also have experience in Machine Learning and Natural Language Processing, having completed an 8-week course in ML and a 6-week NLP course with DataWorkshop. Additionally, I have achieved top percentile rankings on DataCamp's Assessment in R and Python programming skills. Some of my most notable projects include designing and implementing a search engine for pharmaceutical information, creating an Excel-based application for predicting future orders in an extensive retail network, and developing a system for collecting and processing public procurement data in Poland. As a freelancer, I prioritize understanding my client's needs and exceeding their expectations. I pay great attention to detail and am committed to timely delivering tasks. I am fluent in Polish (my native language) and proficient in written and spoken English (upper-intermediate level). I can work up to 120 hours per month, depending on the project requirements. With a proven track record in various data-related projects, I am confident I can deliver excellent results for your business.

Full-Stack AI Lead with 15+ years of experience in AI/ML/Data Engineering. Specialist in productionizing Document AI, Agentic LLM Workflows, and Scalable Big Data systems. Master’s in Applied Mathematics. 𝐀𝐠𝐞𝐧𝐭𝐢𝐜 𝐀𝐈 & 𝐋𝐋𝐌 - Architecting production-grade agents and multi-intent workflows using LangGraph and LangChain. - Implementing NeMo Guardrails, DeepEval, and Langfuse to ensure security and near-zero hallucination rates. - Developing high-performance FastAPI backends for real-time operational data integration. 𝐃𝐨𝐜𝐮𝐦𝐞𝐧𝐭 𝐈𝐧𝐭𝐞𝐥𝐥𝐢𝐠𝐞𝐧𝐜𝐞 & 𝐎𝐂𝐑 - Specialist in extracting structure from "dirty" or non-digital sources using Visual NLP and OCR. - Lead Developer of Spark OCR. - Author and main contributor of open-source projects: Spark PDF and ScaleDP. - Expertise in document layout analysis, data extraction, and semantic search. 𝐏𝐫𝐨𝐝𝐮𝐜𝐭𝐢𝐨𝐧 𝐌𝐋𝐎𝐩𝐬 & 𝐁𝐢𝐠 𝐃𝐚𝐭𝐚 - Architecting scalable infrastructures using Vector DBs (Milvus, Pinecone, Qdrant). - Optimizing Apache Spark (PySpark, Streaming) and Databricks pipelines; reduced processing time from days to hours. - Implementing robust CI/CD via Databricks Asset Bundles, Jenkins, and GitHub Actions. 𝐏𝐫𝐢𝐯𝐚𝐜𝐲 & 𝐂𝐨𝐦𝐩𝐥𝐢𝐚𝐧𝐜𝐞 - Automated de-identification and redaction for GDPR/HIPAA. - Specialist in masking sensitive information in DICOM, PDF, and image formats. 𝐓𝐞𝐜𝐡𝐧𝐨𝐥𝐨𝐠𝐢𝐞𝐬 AI & LLM: LangGraph, LangChain, RAG, Llama 3, Gemini, GPT-4, Vertex AI, Hugging Face, GliNER. Backend: Python, Scala, FastAPI, Node.js, PostgreSQL, MongoDB. Vector DBs: Pinecone, Milvus, Qdrant. Infrastructure: AWS, GCP, Azure, Docker, Kubernetes, Jenkins, AirFlow. Big Data: Apache Spark (PySpark, Streaming, MLlib), Kafka, Kinesis.