Stephan Martin - Sabbatical, professional development

Recommended expert

Weinheim, Germany

Experience

Jan 2024 - Present

2 years 1 month

Sabbatical, professional development

Self-employed

Further training in Snowflake and Google Looker
Working with LLMs: local models (Llama, Mistral, Gemma, Phi, Qwen, DeepSeek, Bitnet, Flux, Whisper), OpenAI API, frontends (ollama, openwebui, loacalai)
Inference methods: llama.cpp, vLLM, transformer
Quantization, benchmarking, prompting
LLM Agents (Tool/Function Calling, LangChain, LangGraph, MCP)
Topics: attention, reasoning, chain of thoughts, RAG, GraphRAG, mlflow
Cloud hosted: ChatGPT, Claude, Gemini

Jan 2022 - Dec 2023

2 years

Berlin, Germany

Data Engineering Architect / Data Analyst / Data Engineer

Init AG

Analyze requirements, design and data modeling
Development, testing and documentation
Operation, maintenance and optimization of data processes
Reporting and requesting changes
Agile approach

Projects:

Archiving EPPSG applications and processes (06/2023–12/2023): testing 2.8 million PDF files (Python), data quality control, archiving, indexing, reporting, delivery
Reporting for the one-time energy price allowance for students (01/2023–06/2023): data modeling and analysis, bug reports, report development, JSON generation for dashboards
Reports for final settlement of the Corona emergency aid (09/2022–03/2023): analysis of existing Excel reports and Freemarker templates, data mapping, creating templates to generate SQL and Excel data
Reports for processing logs of the KONSENS mediation process (01/2022–05/2022): importing, converting and preparing data, linking with Pega data, creating CSV reports

Jul 2021 - Dec 2021

6 months

Berlin, Germany

Data Engineer

D4L data4life gGmbH

Connecting BI event data and mapping JSON data
Building and maintaining the data model
Replacing a database with BI events as the data source
Designing, implementing and testing Airflow DAGs
Coordination with backend developers, data analysis, documentation and database optimization

Technologies: Confluence, Jira, Slack, Google Workspace, GitHub, Docker/Kubernetes, PostgreSQL, Airflow, Python, Metabase

Apr 2018 - Mar 2020

2 years

Frankfurt, Germany

Data Engineer

DB Analytics (Deutsche Bahn)

Designing, implementing and maintaining a datamart including ETL to analyze energy savings of DB Cargo
Comparing data quality of IoT devices from different manufacturers for DB Schenker; providing comparable data for data scientists
Analyzing geodata from IoT devices: stop detection with R and PostGIS, geofencing, migration to AWS Aurora
Designing and implementing a DWH including ETL for line operations analyses of DB Schenker

Technologies: AWS EC2, S3, Aurora, PostgreSQL, PostGIS, MS SQL, 3NF modeling, GitLab, Docker, Python, Bash, SQL, PL/pgSQL, R, REST, JSON, CSV, Confluence, Jira, Slack, MS Teams

Nov 2015 - Oct 2017

2 years

Leverkusen, Germany

Technical Project Manager / IT Engineer

Bayer Business Services GmbH

Development of a tool for MS SQL licensing (PowerShell, MS SQL, Excel)
Implementation of PAM and IAM roles with a least-privilege approach and proof of concept
Analysis of IAM and PAM processes, reporting on MSSQL logins and permissions
Database transition: analysis, planning, creation of guidelines and scripts, managing the migration to ESX clusters
SQL lifecycle management: lifecycle analysis, reporting, guidelines, scripts, change management according to corporate policies

Feb 2015 - Jul 2015

6 months

Viernheim, Germany

Technical Consultant

Degoya Medienkommunikation oHG

Design and implementation of a reservation and voucher system for the hospitality industry using MODX, Ext JS, and MySQL

Nov 2013 - Apr 2014

6 months

Neuenstein, Germany

Technical Consultant

GLS

Design and implementation of interfaces for data migration and system integration using DB2, Siebel, Informix, stored procedures, and shell scripts

Jan 2010 - Apr 2012

2 years 4 months

Business Intelligence Architect – Customer Care

1&1 Internet AG

Responsible for BI strategy and KPI development, and integration of new data sources
Requirements management, design of data models and ETL processes, and data analysis for project control
Projects: integration of the SABIO knowledge management system into the data warehouse, design of near-real-time reporting, evaluation of Talend and Pentaho Kettle as ETL solutions

Apr 2008 - Dec 2009

1 year 9 months

Head of Business Intelligence – Customer Care

1&1 Internet AG

Established and led the BI department for Customer Care (6 team members)
Strategic alignment, integration of new systems, infrastructure expansion, and process and team development
Projects: evaluation of MS SQL Server as a BI solution, implementation of slowly changing dimensions, consolidation of product and organizational dimensions, and preparation for the implementation of MicroStrategy

Apr 2007 - Mar 2008

1 year

Business Intelligence Developer

1&1 Internet AG

Definition, implementation and quality control of performance metrics for support centers
Data analysis for project control and dashboard development using Perl and Excel
Ensuring data availability and quality from InstantOLAP, web front ends, databases, and CSV files

Jul 2002 - Mar 2007

4 years 9 months

Head of Data Management

Schlund+Partner AG

Building and leading the Data Management team (5 people)
Planning and execution of subprojects, resource planning, training and staff meetings
Consulting in process and data modeling
Projects: Internationalization of hosting products, migration of the products for 1&1 and Web.de to a central technical database

Oct 2000 - Jun 2002

1 year 9 months

Developer Data Management

Schlund+Partner AG

Ensuring consistency of technical customer contract data and maintaining rate and contract data
Incident and problem management, process and data modeling, development of a framework for data maintenance
Adapting Schlund+Partner contracts to the 1&1 billing system

Dec 1998 - Oct 2000

1 year 11 months