VPN Experts

As part of this project, the existing active network infrastructure was modernized and made fit for the future. The goal was to introduce a powerful, secure and scalable network and WLAN infrastructure, including a Network Access Control (NAC) solution to improve network security and centralized access control.

At the beginning of the project, a comprehensive requirements analysis was carried out, taking into account the technical, operational and security-related requirements of the hospital sites. On this basis, a technical tender was prepared for new switches, WLAN access points and the NAC solution.

The successful implementation of the project established a modern, standardized and secure network infrastructure that meets the growing requirements for availability, mobility and IT security in hospital operations.

Activities:

• Supporting the tender process, including technical evaluation of offers and bidder evaluation
• Leading and managing the entire project implementation
• Coordinating the project process with internal stakeholders, business units and hospital IT
• Managing external service providers during the implementation and installation of the systems
• Monitoring the implementation, including quality control, project acceptance and defect management
• Coordinating and managing communication between hospital IT and external service providers as part of the NAC implementation
• Managing escalations in the event of technical and organizational challenges
• Ongoing budget monitoring and control of project expenses and additional costs
• Preparing decision papers for management on project changes, additional services and risks

Maturing their API practices on both a business and technology level. My role covers strategy, architecture, developer advocacy as well as hands-on software engineering, enabling both technical teams and business leadership to adopt and act on API-centric principles effectively. Coincidentally, we also establish GitOps, DX and platform best practices with this project.

Highlights:

• Aligning executives with the initiative by clarifying strategy, replacing misconceptions and myths with facts, clarifying the value of existing assets and enabling informed decision-making
• Formulating a way forward for API Lifecycle Management at OTTO
• Driving platform progress and fostering developer engagement by hands-on engineering work towards strategic goals

API Lifecycle Management, Team Topologies, Organizational Evolution, Regulatory, Platform Advocate, Developer Platform, Communities of Practice, Terraform, Kotlin, Kafka, Kong, WSO2, Apigee, Gravitee, Backstage, AsyncAPI, OpenAPI, API Design, AWS, React, Node.js, TypeScript, Redocly, reactive programming, CDC, Golang, Gin, GitOps, DX (developer experience), stakeholder management, roadmaps, workshops, discovery.

• Technical leadership across hardware, firmware, and software teams; scope: hardware/firmware team (4 people) and leadership group (5 people)
• Consolidated and documented a product family that had grown over more than 15 years and aligned it with CRA compliance — from the bare-metal I/O module to the cloud interface.
• Provided the most important customer product with the essential requirements and architecture documentation within two months — for a firmware landscape that had grown over more than 15 years. It now supports the customer’s modernization strategy.
• Established a monthly reporting line to the supervisory board and executive board within three months: nine meetings since 12/2025. The report itself is versioned and built from the CI pipeline; it is based on automatically collected activity and release data instead of assessments.
• Built a container-based CI/CD infrastructure from scratch: cross-compilation, host tests, and documentation builds in one continuous pipeline.
• Introduced declarative QA gates for DevOps and development artifacts — from the start using lefthook instead of pre-commit, executed in a dedicated container image.

Technologies used: arc42, req42, tpo42, docToolchain, PlantUML, ArchiMate, C4 model, ADR, C, C++ (GTest), CMake, Bare Metal (ARM Cortex-M3/M7), OCI containers, Jenkins, lefthook, Prometheus, Grafana, SBOM, CRA, OPC, SCADA, PLC integration, IPv6 migration, Zero Trust, Sociocracy 3.0, Cynefin

• Implementation of a full-stack application with Angular as frontend framework and Java as backend language
• Use of the Swagger OpenAPI specification for REST communication between frontend and backend applications
• Control of a card printer via the Nexus Card SDK framework
• Design and implementation of card management software with web interface and JavaFX module for printer monitoring
• Use of Cucumber tests for test automation and creation of test artifacts for testing outside the development environment
• Use of Wireshark for network investigations to analyze the API of a third-party product and to check the REST API of the self-developed software

• Operation and further development of the network and security infrastructure.

• Monitoring, analysis and resolution of network and security incidents.

• Cross-department collaboration with other specialist teams for operations, further development and reporting.

• Firewall vulnerability analysis.

• Firewall rule approvals.

• Troubleshooting IP communication issues in the network and firewall infrastructure.

• Security-critical IT infrastructure, processing of personal data, compliance with legal regulations.

• Products: Palo Alto Networks Firewalls, Cisco ACI, Checkpoint Firewalls, F5

• Technologies: SDN, SDWAN, Cisco EPIC, Cisco ACI

• Technical management of parallel rooftop PV projects (Type A/B) from project planning through construction to completed plant certification
• Analysis of project requirements based on on-site inspections, planning reviews and evaluation of tender and project documents, and preparation of the findings for the internal planning department
• Derivation of work packages and milestones for each project, including structured filing in the client’s project documentation (SharePoint)
• Coordination of the planning phase between planning, procurement and executing trades
• Preparation of specifications and bills of materials as the basis for preparing quotations, and monitoring the timely submission of offers
• Coordination and monitoring of the construction phase, including schedule tracking and ensuring implementation in line with the plans
• Preparation and continuous updating of project schedules and project budgets across all projects
• Tracking of milestones, work packages and project progress, as well as early documentation and escalation of schedule and budget deviations to the overall project management
• Preparation of technical analyses of existing and planning data for each plant as the basis for the entire certification process
• Review, verification and compilation of all certification-relevant evidence: technical data sheets, manufacturer approvals, component documentation, test reports, type certificates and simulation results
• Assessment of the completeness and compliance of manufacturer documentation with applicable standards, identification of missing evidence, and requesting and tracking missing documents from manufacturers and installers
• Preparation and technical review of declarations of conformity for the grid connection of the plants
• Preparation of complete plant certification documentation for Type A/B in accordance with the applicable VDE application rules, the grid operators’ technical connection requirements (TAB) and the requirements of the certification bodies
• Review and documentation of protection concepts, as well as definition of the certification scope for each plant in technical coordination with the grid operators
• Submission of documents to grid operators and accredited certification bodies, follow-up on queries through final approval, and deadline management across parallel procedures
• Management of interfaces between the client, manufacturers, installers, grid operators and certification bodies, as well as complete project documentation with status overviews, communication logs and approval documents

Project: Process optimization & IT support in an insurance broker office.

Project activities:

• Analysis of processes and definition of requirements
• Consulting for the implementation of a cloud solution (soho)
• Installation and verification of new infrastructure HW
• Cloud installation & configuration
• Definition and creation of use cases
• Performing user acceptance tests (UAT)
• User training / training
• IT support (cloud, PC, server, printer, network)

Label: Insurance, infrastructure, configuration, training, support

Gronic Ident & Sign

Core technologies: Android, Jetpack Compose, Retrofit, Regula Document Reader, Adobe Sign

Android app on dedicated devices for identifications and electronic signatures at the PoS

• Built Azure Kubernetes clusters (AKS) with network policies, security groups, and RBAC
• Terraform-based infrastructure as code for secure, reproducible deployments in the BMW Azure cloud
• Hardened CI/CD pipelines with Jenkins, SonarQube, Fortify SSC, and Contrast AST
• Integrated SAP BTP/Kyma and ServiceNow GRC

• Built and further developed an AWS landing zone based on Terraform / OpenTofu (multi-account structure, IAM baselines, network and security standards)
• Designed and operated platform-oriented AWS architectures to standardize infrastructure and operations processes
• Built and operated Kubernetes-based platforms (EKS) as a shared runtime environment for application teams
• Established GitOps-based deployments with Argo CD and FluxCD
• Developed and operated central CI/CD platforms (GitLab CI, GitHub Actions, Jenkins)
• Enabled development and project teams through reusable platform building blocks
• Introduced and implemented FinOps structures (AWS Cost Explorer, CUR + Athena, Infracost, Grafana dashboards)
• Built and operated central observability platforms (Prometheus, Grafana, Loki, Alertmanager, CloudWatch)

• Error analysis and fixes including performance optimization of the in-house developed platform API
• Change and incident management in day-to-day operations
• Responsible for compliance with security and compliance requirements
• Vendor management for software development and maintenance
• Planning and execution of migration of legacy services to a cloud native platform

Role in the project: project staff, implementation team

Used skills: requirements analysis, IT service and application management, IT operations, error analysis and performance optimization, software maintenance and lifecycle management

Project environment: Cloud Native Platform (Kubernetes, Crossplane, AWS, ArgoCD, Grafana)

• Fine-tuned and evaluated alternative backbone architectures for the AFFGAN handwriting style encoder to better capture writer-specific features, benchmarking against the original baseline architecture and replacing the legacy VGG19 architecture with a custom Transformer-based encoder.
• Extended the system beyond word-level synthesis to line-level handwriting generation, integrating and adapting an existing line-generation architecture to support full-sentence output.
• Deployed the handwriting generation pipeline as a web application, enabling users to select a writing style, input custom text, and instantly generate a corresponding handwriting image.
• Integrated TrOCR into a teacher–student distillation framework to evaluate and improve readability of generated handwriting, improving OCR accuracy by 20% over the baseline.
• Boosted user-study pick-rates by 40%, demonstrating a significant leap in the perceptual quality and realism of the generated handwriting compared to the baseline model.

Tech: PyTorch, Python, GANs, CNN, ViT, TrOCR, Streamlit, CUDA.

• Development and introduction of operations processes
• Preparation of complete documentation packages (including incident management and operations support) to meet compliance requirements
• Introduction of a workshop on IaC (Infrastructure as Code)
• Technical consulting for the project security concept (ISMS)
• Installation and operation of Kubernetes clusters on AWS, on-prem, and Azure
• Hybrid cloud architecture design (on-prem, Hetzner, AWS)
• Analysis and troubleshooting of incidents and system outages
• Network adjustments for firewall rules, gateways, OpenVPN settings, and IPsec tunnels (pfSense)
• Technical consulting on Bitbucket, Jenkins, and GitLab CI/CD pipelines
• Consulting on Ansible deployments and infrastructure automation
• Consulting on building a scalable system in the cloud (AWS / Azure)
• Technologies / Tools: Ansible, Terraform, AWS, Azure, VPN, pfSense, Jenkins, Bitbucket, Kubernetes, GitLab Runner, ISMS, Golang, Prometheus, Grafana, S3, Lambda, RDS, ECS, Cognito, OIDC, Harbor, MinIO, Postgres, Redis, Keycloak, Ceph, Proxmox, CloudFormation, PostgreSQL, Flux CD, Hetzner, IONOS, Sonatype Nexus Repository, Entra ID, Dex IdP, Pulumi

Task:

• Design and build a proof of concept (PoC) for a future-proof virtualization platform, taking secure system architectures into account
• Assess the current state of existing infrastructures and develop selection and evaluation criteria for the right OS virtualization platform
• Carry out the requirements analysis and then create and prioritize tickets in the ticket system
• Complete and continuously update a tool evaluation matrix based on PoC results
• Support team knowledge building through clear documentation of the approach and results in Confluence
• Enterprise analysis of existing hardware (creating different BoMs)

Technologies: Vmware, Vmware Aria Operations, Osism, Canonical OpenStack, FishOs, Linux, Terraform, Ansible, Confluence, Alma