BI Architect

• Designed and implemented automated data reconciliation pipelines to synchronize over 100,000 individual records between UNHCR’s database and partner systems, ensuring referential integrity and improving interoperability across 11 EHAGL country operations.
• Developed a biometric-linked resettlement case management workflow using SQL Server and Power BI. Created custom ETL scripts, Power Query transformations, and DAX-based KPIs to support interactive dashboards.
• Led training sessions for over 60 field and headquarters staff on structured query design, data pipeline troubleshooting, and Power BI performance optimization, promoting decentralized data analysis.

• Designed and maintained dashboards and automated reporting tools to monitor project performance and enhance workflows.
• Developed and optimized data pipelines using SQL and BigQuery to manage large-scale datasets across multiple UNOPS operational units.
• Utilized advanced data science techniques to improve data quality, reduce latency, and automate reporting workflows.

• Served as a PSP Data Management Specialist (Maternity Cover) at UNHCR Athens, where technical support was provided to the PSP team with a focus on streamlining donor data management and optimizing CRM workflows.
• Designed and implemented automated flowcharts and queries to support donor engagement activities.
• Created SQL-like data extractions for external supplier communications, automated activity registrations within the CRM, and implemented logic-based email triggers to support donor retention—enhancing data accuracy and responsiveness.
• Demonstrated strong capabilities in CRM systems, data analysis, workflow automation, and stakeholder coordination, ultimately delivering measurable efficiency improvements within a time-limited assignment.

• Developed geostatistical models to downscale low-resolution wind predictions using satellite imagery and high-resolution spatial inputs.
• Performed spatial data preprocessing, interpolation, and visualization using R, MATLAB, and SQL-based workflows.
• Combined time series analysis with spatial modeling to produce localized, actionable forecasts for environmental planning.

• Led the development of automated data tools and workflows for UNHCR operations in Northern Greece, significantly improving efficiency in reporting, verification, and case tracking across more than 15 sites.
• Designed GIS-based tools for site mapping and demographic analysis, and managed the local proGres v4 database—reducing recurring data errors by over 70% through validation routines and anomaly detection dashboards.
• Built multilingual public information platforms, including a QR code system accessed by 1,500+ PoCs monthly and a hospital shift tracker used across multiple locations, supporting coordination and service delivery.
• Delivered training to over 60 staff and partners on CRM systems, automation, and Power BI, and authored a multilingual urban services guide adopted by working groups and shared with 5,000+ beneficiaries.

During the 2016 refugee crisis in the Northern Aegean, Stelios worked on the front lines of UNHCR’s data response team, leading efforts to structure and streamline operational data for coordinated action across agencies.

• Coordinated efforts during the emergency refugee influx in the Northern Aegean, leading the first complete registration masterlist for refugees on Chios, which was crucial for scheduling and operational planning by the Asylum Service and EASO.

• Organized and carried out comprehensive mapping exercises to monitor refugee movements. Maintained continuous data updates in collaboration with local authorities, ensuring real-time visibility of arrivals and departures.

• Created a web GIS platform to monitor boat arrivals, supporting first reception actors. This platform improved real-time decision-making and could be replicated on other islands. Provided timely, actionable insights through daily statistical snapshots and operational reports shared with key stakeholders.

• Delivered capacity-building sessions with the Asylum Service and EASO, offering technical training in data systems. Developed briefing kits and site profiles to assist partner planning and humanitarian efforts.

• Enhanced information systems and partner coordination with innovative tools, accurate reporting, and proactive stakeholder engagement in a rapidly changing operational context.

GeoData Bank SA provided cadastral and geospatial consulting services to major banks during Greece’s national land registry rollout. As founder and CEO, Stelios led the complete delivery of data services related to property rights and land documentation.

• Delivered comprehensive cadastral data management services to banking institutions during the drafting of the National Cadastre. Specialized in legal processing of ownership titles, ensuring compliance with Law 2308/95, including drafting and correcting Declarations and resolving documentation gaps and delays.

• Managed the preparation and submission of appeals to Cadastral Offices, tracked progress, and offered real-time consulting support to legal and property departments throughout procedural reviews.

• Supervised updates to internal bank systems concerning finalized rights registration and supported the integration of GIS tools for asset valuation. Enabled efficient portfolio management through precise geospatial analysis, aiding decision-making on property ownership, asset value, and legal compliance across Greece.

The University of the Aegean is a prominent institution in geospatial and environmental sciences. Stelios contributed as a doctoral researcher in spatial analysis, focusing on environmental modeling and uncertainty quantification.

• Conducted advanced research on uncertainty propagation in the spatiotemporal distribution of environmental variables, aiming to enhance prediction accuracy in geospatial and environmental models. Utilized statistical modeling and data science techniques across Geographic Information Science and Earth and Environmental Sciences fields.

• Contributed to the academic community through three peer-reviewed journal publications and several international conference presentations. Assisted in teaching undergraduate and graduate courses, providing support in course delivery and student mentoring.

• Participated in interdisciplinary projects, strengthening expertise in geospatial analytics, environmental modeling, and scientific communication.

InfoDim is a geospatial technology company that provides GIS-based solutions for environmental safety and risk management. Stelios contributed as a GIS expert to a fire prevention project focused on early warning systems and spatial analytics.

• Conducted geospatial data collection, cleaning, and analysis to support fire risk assessment and mitigation planning.
• Developed GIS-based risk models that integrate vegetation, topography, and infrastructure data to inform early warning systems.
• Created mapping deliverables and analytical reports that improved emergency preparedness and operational planning.
• Worked with multidisciplinary teams to ensure the accuracy and relevance of spatial outputs for disaster management agencies.

Makedoniki is a consultancy specializing in land management, urban planning, and geospatial analysis. Over a decade, Stelios contributed to multidisciplinary studies supporting the development of Greece's national cadastre and infrastructure planning.

• Contributed to cadastral, urban planning, and land use studies supporting the establishment of Greece's national cadastre system—applied expertise in legal and technical property rights frameworks to ensure alignment with national land management standards.

• Provided geospatial and topographic survey support for hydraulic, geological, and environmental studies. Delivered consultancy services on land consolidation, spatial planning, and urban development projects, ensuring sustainable and accurate implementation.

• Oversaw project and data management processes, maintaining quality assurance across multidisciplinary studies. Supported cross-sector collaboration with public authorities, surveyors, and technical teams to enhance spatial data governance and planning efficiency.