Stephan Martin

Sabbatical, further training

Weinheim, Germany

Experience

Jan 2024 - Present
1 year 7 months

Sabbatical, further training

Freelancer

  • Topics: Snowflake, Google Looker
  • LLMs: local models (Llama, Mistral, Gemma, Phi, Qwen, DeepSeek, Bitnet, Flux, Whisper), OpenAI API, frontends (ollama, openwebui, loacalai), inference (llama.cpp, vLLM, transformer), quantization, benchmarking, prompting
  • LLM agents: Tool/Function Calling, LangChain, LangGraph, MCP
  • Other: attention, reasoning, chain of thought, 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

  • Technical environment: Confluence, Jira, MS Teams, Cisco Webex, GitLab, git, WSL2, DBeaver, Jupyter, vim, bash, PostgreSQL, psql, Python, MS Excel, VS Code, Java/Freemarker, amCharts 5, TypeScript
  • Requirements analysis, design, data modeling, development, testing, documentation, operation and maintenance, change requests, optimization, reporting
  • Approach: agile
Jul 2021 - Dec 2021
6 months
Berlin, Germany

Data Engineer

D4L data4life gGmbH

  • Technical environment: Confluence, Jira, Slack, Google Workspace, GitHub, Docker/Kubernetes, PostgreSQL, Airflow, Python, Metabase
  • Integration of BI event data, mapping of JSON data, building the data model
  • Replaced a backend service database as data source with BI events
  • Source systems: microservices in Golang, EventStore Elasticsearch; data delivery as JSON into PostgreSQL
  • Mapping to relational modeling with SQL views, generating SQL from YAML
  • ETL using Airflow DAGs, test environment in Docker, reporting with Metabase
  • Design, implementation, testing, coordination with developers, data analysis, documentation, database optimization
Apr 2020 - Jun 2021
1 year 3 months

COVID-19 (risk group)

Self-Employed

Due to being in a household risk group and caring for a child, no projects were taken on

Apr 2018 - Mar 2020
2 years
Frankfurt, Germany

Data Engineer

DB Analytics (Deutsche Bahn)

  • Technical environment: AWS EC2, S3, Aurora, PostgreSQL, PostGIS, MS SQL, 3NF modeling, Git, GitLab, Docker, Ubuntu Server, OpenSUSE, MS Windows, Python (yaml, psycopg2, SQLAlchemy, graphviz), Bash, SQL, PL/pgSQL, R, REST, JSON, CSV, Confluence, Jira, Slack, MS Teams
  • Design, implementation and maintenance of a data mart and ETL for analyzing energy savings of DB Cargo
  • Comparison of data quality of IoT devices from various vendors to assess DB Schenker's line transports
  • Analysis of IoT device geodata: stop detection with R and PostGIS, geofencing
  • Design and implementation of a DWH and ETL for evaluating DB Schenker's scheduled services
  • Using YAML for metadata, Bash/Python for data ingestion, PL/pgSQL for transformation, logging, error reporting
Nov 2015 - Oct 2017
2 years
Leverkusen, Germany

Technical Project Manager, IT Engineer

Bayer Business Services GmbH

  • Technical environment: Windows Server/Cluster, MS SQL Server, SSMS, SSDT, SSIS, SSAS, SSRS, HPSM, Lotus Notes, MS Office, Jira, Git, VS Code, PowerShell, RDP
  • Developed a tool to support MS SQL licensing using PowerShell, MS SQL, Excel
  • Implemented PAM and IAM roles with least privileges: concept, PoC, managed service control
  • IAM and PAM analysis, reporting on MSSQL logins, evaluation according to corporate guidelines
  • Database transition: analysis, target state, guidelines, checklists, scripts, transition management
  • SQL lifecycle management: analysis, target state, reporting, scripts, updates, handover to managed service
Feb 2015 - Jul 2015
6 months
Viernheim, Germany

Technical Consultant

Degoya Medienkommunikation oHG

  • Technical environment: MODX, Ext JS, MySQL
  • Designed and implemented a reservation and voucher system for the hospitality industry
Nov 2013 - Apr 2014
6 months
Neuenstein, Germany

Technical Consultant

GLS

  • Technical environment: DB2, Siebel, Informix, Stored Procedures, Shell
  • Designed and implemented interfaces for data migration and system integration
Jan 2010 - Apr 2012
2 years 4 months
Karlsruhe, Germany

Architect Business Intelligence – Customer Care

1&1 Internet AG

  • Technical environment: Sybase ASE, PostgreSQL, Perl, Bash, Excel, Talend, Pentaho Kettle, star/snowflake schema, 3NF
  • Business intelligence strategy, developing new KPIs, connecting new data sources
  • Requirements management, design of data models and ETL processes, data analysis for project management
  • Projects: connecting SABIO to DWH, infrastructure for near real-time reporting, evaluating Talend/Pentaho
Apr 2008 - Dec 2009
1 year 9 months
Karlsruhe, Germany

Head of Business Intelligence – Customer Care

1&1 Internet AG

  • Technical environment: Sybase ASE, Sybase IQ, star/snowflake schema, SSAS OLAP
  • Built and led BI Customer Care (6 staff), strategic direction, system integration
  • Requirements management, infrastructure expansion, process implementation, staff development
  • Projects: evaluating MS SQL Server, implementing slowly changing dimensions, consolidating dimensions, preparing MicroStrategy
Apr 2007 - Mar 2008
1 year
Karlsruhe, Germany

Developer Business Intelligence

1&1 Internet AG

  • Technical environment: Sybase IQ, OLAP, star/snowflake schema, 3NF, Perl, Excel
  • Defined, implemented and quality-checked control metrics for support centers
  • Data analysis for project controlling, dashboard development for Access products
Jul 2002 - Mar 2007
4 years 9 months
Wiesbaden, Germany

Head of Data Management

Schlund+Partner AG

  • Technical environment: Sybase ASE, MySQL, Sqsh, Perl, Debian
  • Built and led data management (5 staff), resource planning, subproject planning
  • Process monitoring, data modeling, staff development
  • Projects: internationalization of hosting products, migration to 1&1, migration of Web.de products
Oct 2000 - Jun 2002
1 year 9 months
Wiesbaden, Germany

Developer Data Management

Schlund+Partner AG

  • Technical environment: Sybase ASE, OLTP, Sqsh, Bash, Perl, XML, XSLT, SUSE Linux
  • Ensured consistency of technical customer attributes, maintained tariff and contract data
  • Incident and problem management, process and data modeling, framework development
Dec 1998 - Oct 2000
1 year 11 months
Wiesbaden, Germany

Support

Schlund+Partner AG

  • Phone support for hosting products outside business hours
Oct 1997 - Nov 1998
1 year 2 months
Wiesbaden, Germany

Developer

Schlund+Partner AG

  • Technical environment: Perl, PHP, SQL, Solid DBMS, OLTP, Apache, IRIX, Debian, SUSE Linux
  • Developed and maintained the “Private Homepages” product, backed up all Unix servers and workstations

Summary

Over 30 years of IT experience solution-oriented, sustainable, analytical, creative

Languages

German
Native
English
Advanced

Education

Flinders University

Computer Science · Adelaide, Australia

Universität Kaiserslautern, Fernuni Hagen

Diploma · Computer Science · Hagen, Germany

Certifications & licenses

Google Looker

credly.com

Snowflake - Hands-On Essentials

Snowflake

CDVP2 Certified Data Vault 2.0 Practitioner

ScaleFree

Dbt Fundamentals

learn.microsoft.com

Microsoft AI Fundamentals (AI-900)

learn.microsoft.com

Microsoft Azure Fundamentals (AZ-900)

learn.microsoft.com

Microsoft Data Fundamentals (DP-900)

learn.microsoft.com

Microsoft Power Platform Fundamentals (PL-900)

learn.microsoft.com

MicroStrategy Architect

MicroStrategy

MicroStrategy Reporting

MicroStrategy

Fundamentals of Microsoft Office Project Server 2007

Campana & Schott

Certified ScrumMaster

Certified ScrumMaster

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