Federated Learning in Dynamic and Heterogeneous Environments for European Digital Healthcare:
From Theoretical Framework to Implementation in Italian Hospitals
Titolo originale (IT)
Federated Learning in Ambienti Dinamici ed Eterogenei per la Sanità Digitale Europea:
Dal Framework Teorico all'Implementazione negli Ospedali Italiani
PhD Thesis — Fabio Liberti
www.fenith.org
- Overview
- Research Questions
- At a Glance
- Timeline
- Datasets
- FL Algorithms
- Repository Structure
- Platforms · Applications · Governance · Foundations
- Publications
- Getting Started
- License
- Author
- Institutions & Collaborations
- Acknowledgements
- Keywords
This repository serves as the central hub for the PhD research project on Federated Learning (FL) applied to the European Health Data Space (EHDS). It aggregates all research artifacts — experimental platforms, domain-specific applications, governance frameworks, foundational studies, published papers, and thesis documents — into a single, structured meta-repository.
| Question | Cluster | |
|---|---|---|
| RQ1 | Technological Framework — How to design Federated Learning architectures capable of handling the high statistical, infrastructural, and participation heterogeneity of hospital nodes, while ensuring scalability, efficiency, and reliability of distributed training? | Platforms |
| RQ2 | Multidimensional Governance — Which governance models can balance technological innovation, regulatory compliance (GDPR/EHDS), economic sustainability, and socio-ethical principles, enabling federated trust networks in healthcare? | Governance |
| RQ3 | Practical Adoption — What are the main barriers and enabling conditions for the effective adoption of Federated Learning in Italian hospitals, in technological, organizational, and cultural terms? | Applications |
| RQ4 | EHDS Interoperability — How can Federated Learning be integrated with international healthcare standards (HL7/FHIR, OMOP/OHDSI) to ensure full compatibility with the European Health Data Space? | Platforms · Governance |
Research Questions (IT)
| Domanda | Cluster | |
|---|---|---|
| RQ1 | Framework Tecnologico — Come progettare architetture di Federated Learning in grado di gestire l'elevata eterogeneità statistica, infrastrutturale e di partecipazione dei nodi ospedalieri, assicurando scalabilità, efficienza e affidabilità del training distribuito? | Platforms |
| RQ2 | Governance Multidimensionale — Quali modelli di governance possono bilanciare innovazione tecnologica, conformità normativa (GDPR/EHDS), sostenibilità economica e principi etico-sociali, abilitando reti federate di fiducia nel contesto sanitario? | Governance |
| RQ3 | Adozione Pratica — Quali sono le principali barriere e condizioni abilitanti per l'adozione effettiva del Federated Learning negli ospedali italiani, in termini tecnologici, organizzativi e culturali? | Applications |
| RQ4 | Interoperabilità EHDS — In che modo il Federated Learning può essere integrato con gli standard sanitari internazionali (HL7/FHIR, OMOP/OHDSI) per garantire la piena compatibilità con l'EHDS? | Platforms · Governance |
See the full architecture diagram for a visual overview.
Fig. 1 — FENITH Research Architecture Diagram
Hierarchical map of the entire FENITH meta-repository, showing the flow from Research Components & Inputs (left) to Research Outputs (right). The diagram is organized into five color-coded layers:
- Foundations (grey) — DHFLPL2 (seminal paper, MDPI 2024), Heterogeneous FL educational collection, HFEDL_Project, and the private thesis repository (
tesi_fl_2025). These feed into the experimental platforms. - Experimental Platforms (blue) — Three FL research platforms: flopbg (TensorFlow/React, Bambino Gesù collaboration), BLEKFL2 (PyTorch/Flower, Blekinge collaboration), and FL-EHDS-FLICS2026 (Python, EHDS compliance framework). Each platform connects to specific conference publications on the right.
- Domain-Specific Applications (orange) — Five applied repositories: Questionnaire_FL (hospital adoption survey), CIDE (OMOP/FHIR business models), CIDE2 (XAI deepfake detection), FedHR5.0 (Industry 5.0 HR), and CRISTAIN2025 (law enforcement FA-FedAvg). Each is mapped to its corresponding conference paper.
- Governance & Ethics (green) — Three governance-focused repositories: AI-DIGOSA (ethics/regulation tensions), icsis2026 (health policy infrastructure), and ICID2026 (EHDS reference architecture with IDSA/Data Mesh).
- Research Outputs (right column) — All 10 publications (P-M through IFKAD), thesis documents, survey materials, and the final PhD Thesis & Dissertation Framework (EHDS).
Arrows trace the lineage from foundational work through platforms and applications to published outputs.
Fig. 2 — FENITH Project Infographic
Visual summary of the FENITH meta-repository, designed as a single-page overview with four main sections:
- Central Hub (top center) — Shows FENITH as the aggregation point linking all research artifacts: platforms, applications, governance frameworks, foundational studies, papers, and thesis documents. Includes the repository URL and website link.
- Four Clusters (middle row) — Each cluster is presented as a card with its repositories:
- Platforms (teal): flopbg, BLEKFL2, FL-EHDS-FLICS2026 with their tech stacks and key metrics.
- Applications (orange): Questionnaire_FL, CIDE, CIDE2, FedHR5.0, CRISTAIN2025 with domain labels.
- Governance (blue): AI-DIGOSA, icsis2026, ICID2026 with focus areas.
- Foundations (grey): DHFLPL2, DHFLPL, Heterogeneous_FL, plus private repos.
- Repository Structure (top right) — Tree view of the directory layout (
platforms/,applications/,governance/,foundations/,docs/). - Publications (bottom left) — Complete table of all 10 papers with codes, titles/conferences, years, and status. Includes DOI link for the foundational P-M paper.
- Getting Started (bottom right) — Clone instructions with
--recurse-submodulesand the private repo access note. - Footer — Author, affiliation, license (CC BY-NC-SA 4.0).
| FL Algorithms | 38 unique across 3 platforms (FedAvg, FedProx, SCAFFOLD, FedNova, MOON, ...) |
| Datasets | 35 total — 5 benchmark, 6 clinical imaging, 19 healthcare (+ 5 shared) |
| Experiments | 6,000+ (FL-EHDS-FLICS2026 alone) |
| Publications | 10 papers — 1 published (21 citations), 3 presented, 2 accepted, 4 submitted |
| Conferences | MDPI, ISM, CRISTAIN, CIDE, ITAIS, FLICS, ICSIS, ICID, IFKAD |
| Submodules | 16 repositories (14 public + 2 private) |
| Frameworks | TensorFlow, PyTorch, Flower, Flask, React |
gantt
title FENITH Research Timeline
dateFormat YYYY-MM
axisFormat %b %Y
section Foundations
Heterogeneous FL study :done, 2023-10, 2024-06
P-M MDPI Applied Sciences :done, pm, 2024-06, 2024-09
DHFLPL platform (v1) :done, 2024-03, 2024-09
DHFLPL2 systematization :done, 2024-09, 2025-03
section 2025 Conferences
P-IT ITAIS 2025 :done, 2025-03, 2025-06
P-IS ISM 2025 (Malta) :done, 2025-06, 2025-11
P-CR CRISTAIN 2025 (CHItaly) :done, 2025-06, 2025-10
P-C1 CIDE 2025 (Ploiesti) :done, 2025-07, 2025-10
P-C2 CIDE 2025 (XAI DeepFake) :active, 2025-07, 2025-10
Questionnaire FL Italian Hospitals :done, 2024-11, 2025-07
section Platforms
flopbg (Bambino Gesù) :done, 2024-09, 2026-03
BLEKFL2 (Blekinge) :done, 2025-07, 2026-03
FL-EHDS-FLICS2026 :done, 2026-01, 2026-03
section 2026 Submissions
FLICS 2026 (Valencia, IEEE) :active, 2026-01, 2026-06
ICSIS 2026 (Valencia) :active, 2026-01, 2026-06
ICID 2026 (Ulaanbaatar, Springer):active, 2026-01, 2026-05
IFKAD 2026 (Budapest) :active, 2026-01, 2026-07
section Internships
OPBG — Ospedale Pediatrico Bambino Gesù :crit, done, 2023-10, 2025-03
BTH — Blekinge Institute of Technology (Sweden) :crit, active, 2025-04, 2026-09
section Thesis
FENITH meta-repo :active, 2026-03, 2026-09
PhD Thesis writing :active, 2026-03, 2026-05
Thesis delivery :milestone, 2026-05-31, 0d
Thesis defense :active, 2026-06, 2026-12
35 datasets across 3 platforms (click to expand)
| Dataset | Samples | Classes | Format |
|---|---|---|---|
| MNIST | 70,000 | 10 | 28x28 grayscale |
| Fashion-MNIST | 70,000 | 10 | 28x28 grayscale |
| CIFAR-10 | 60,000 | 10 | 32x32 RGB |
| CIFAR-100 | 60,000 | 100 | 32x32 RGB |
| SVHN | 99,289 | 10 | 32x32 RGB |
| Dataset | Domain | Classes | Platform |
|---|---|---|---|
| Brain Tumor MRI | Neuro-imaging | 4 (glioma, meningioma, pituitary, no tumor) | flopbg |
| ISIC Skin Lesion | Dermatology | 9 (melanoma, nevus, BCC, ...) | flopbg |
| Chest X-Ray | Radiology | 2 (normal, pneumonia) | flopbg |
| Diabetic Retinopathy | Ophthalmology | 5 (no DR — proliferative) | flopbg |
| Skin Cancer | Dermatology | 2 (benign, malignant) | flopbg |
| Brain Tumor (Alt.) | Neuro-imaging | 4 | flopbg |
Primary evaluated (8)
| Dataset | Domain | Samples | Compliance |
|---|---|---|---|
| PTB-XL ECG | Cardiology | 21,799 | 52 EU sites |
| Cardiovascular Disease | Cardiology | 70,000 | — |
| Diabetes 130-US Hospitals | Endocrinology/EHR | 101,766 | ICD-9 |
| Heart Disease UCI | Cardiology | 920 | 4 hospitals |
| Breast Cancer Wisconsin | Oncology | 569 | — |
| Chest X-Ray | Radiology | 5,856 | DICOM |
| Brain Tumor MRI | Neuro-imaging | 7,023 | DICOM |
| Skin Cancer (ISIC) | Dermatology | 3,297 | DICOM |
Additionally supported (11)
| Dataset | Domain | Samples | Compliance |
|---|---|---|---|
| Stroke Prediction | Neurology | 5,110 | — |
| CDC Diabetes BRFSS | Epidemiology | 253,680 | — |
| CKD UCI | Nephrology | 400 | — |
| Cirrhosis Mayo | Hepatology | 418 | — |
| Synthea FHIR R4 | Synthetic EHR | 1,180 | FHIR R4 |
| SMART Bulk FHIR | EHR Standards | 120 | FHIR |
| FHIR R4 Synthetic | Synthetic | configurable | FHIR R4 |
| OMOP-CDM Harmonized | Clinical Data Model | configurable | OMOP v5.4 |
| Diabetic Retinopathy | Ophthalmology | 35,126 | — |
| Brain Tumor MRI (Alt.) | Neuro-imaging | 3,264 | — |
| ISIC Skin Lesions | Dermatology | 2,357 | — |
38 unique algorithms across 3 platforms (click to expand)
| Algorithm | Description | flopbg | BLEKFL2 | FL-EHDS |
|---|---|---|---|---|
| FedAvg | Weighted parameter averaging (McMahan et al., 2017) | Y | Y | Y |
| FedProx | Proximal regularization for non-IID data (Li et al., 2020) | Y | Y | Y |
| SCAFFOLD | Control variates for client-drift correction | Y | — | Y |
| FedNova | Normalized averaging for unequal local steps | Y | — | Y |
| FedDyn | Per-client dynamic regularizer | Y | — | Y |
| FedExP | Extrapolation-based dynamic step size (POCS) | Y | — | Y |
| FedSpeed | Proximal term with gradient perturbation correction | Y | — | Y |
| Algorithm | Description |
|---|---|
| MOON | Model-contrastive loss aligning local/global representations |
| FedDisco | KL-divergence weighted client contributions |
| FedLPA | Layer-wise precision-weighted (posterior) aggregation |
| DeepAFL | Frozen feature layers + ridge regression classifier |
| FedEL | Elastic layer selection with configurable budget |
| Algorithm | Description |
|---|---|
| FedAvg-Optimized | Enhanced FedAvg with SGD momentum, cosine annealing, AMP |
| FedLaS | Class-weighted loss with knowledge distillation |
| FedAvgM | Server-side momentum variant |
| q-FFL | Fairness-aware client weighting (Li et al., 2020) |
| NoiseAwareFL | Client filtering by data quality score |
| RobustAggregation | Outlier-robust aggregation |
| FedBN | Local batch normalization (Li et al., 2021) |
| AdaptiveFL | Drift detection with adaptive learning rate |
| ContinualFL | Continual learning with task boundaries |
| EWC | Elastic Weight Consolidation (Kirkpatrick et al., 2017) |
| MetaLearningFL | MAML-based inner/outer optimization |
| DomainGeneralizationFL | Domain-invariant feature representations |
| TransferFL | Transfer learning across domains |
| RegularizationFL | SI / MAS / L2 regularization methods |
| ReplayBasedFL | Experience and generative replay |
| ArchitecturalFL | Progressive networks, PackNet, Piggyback |
| Algorithm | Description |
|---|---|
| FedAdam | Server-side Adam momentum |
| FedYogi | Controlled adaptive learning rate |
| FedAdagrad | Server-side gradient accumulation |
| Per-FedAvg | MAML-based meta-learning personalization |
| Ditto | L2-regularized personal model training |
| FedLC | Logit calibration for label skew |
| FedSAM | Sharpness-aware flat minima optimization |
| FedDecorr | Decorrelation against dimensional collapse |
| FedLESAM | Globally-guided sharpness-aware (ICML 2024 Spotlight) |
| HPFL | Shared backbone + personalized classifiers (ICLR 2025) |
| Defense | Description |
|---|---|
| Krum / Multi-Krum | Distance-based robust aggregation |
| Trimmed Mean | Trims outlier gradients before averaging |
| Coordinate-wise Median | Per-coordinate median aggregation |
| Bulyan | Krum + trimmed mean combination |
| FLTrust | Server-guided trust scoring |
FENITH/
├── assets/ # Logo, diagrams, infographics
├── platforms/ # Experimental FL platforms (submodules)
├── applications/ # Domain-specific FL applications (submodules)
├── governance/ # Governance, policy, and ethical frameworks (submodules)
├── foundations/ # Foundational research and educational materials (submodules)
├── docs/
│ ├── thesis/ # Thesis documents and outlines
│ ├── papers/ # Published and submitted papers (see INDEX.md)
│ ├── questionnaire/ # Survey research materials
│ ├── architecture.md # Mermaid architecture diagram
│ └── README.md # Documentation guide
├── .github/workflows/ # CI: link checker
├── CITATION.cff # BibTeX citation for the foundational paper
├── CONTRIBUTING.md # Contribution guidelines
├── CHANGELOG.md # Version history
├── SECURITY.md # Security and responsible disclosure policy
└── LICENSE # CC BY-NC-SA 4.0
| Repository | Description | Stack | RQ |
|---|---|---|---|
| flopbg | FL research platform — Universitas Mercatorum & Ospedale Pediatrico Bambino Gesù. 12 FL algorithms, 11 datasets (5 benchmark + 6 clinical). | Python, Flask, TensorFlow, React | RQ1, RQ3 |
| BLEKFL2 | FL research platform — Blekinge Institute of Technology (Sweden) & Universitas Mercatorum. 17+ FL algorithms, Flower framework. | Python, Flask, PyTorch, Flower | RQ1, RQ4 |
| FL-EHDS-FLICS2026 | FL + EHDS governance framework. 17 FL algorithms, 19 healthcare datasets, differential privacy, secure aggregation. | Python | RQ1-2-3-4 |
| Repository | Description | Domain | RQ |
|---|---|---|---|
| Questionnaire_FL | Research questionnaire on FL adoption in Italian hospitals. 34 questions, systematic literature review. | Healthcare Adoption | RQ3 |
| CIDE | Federated Learning Health Data Platform - OMOP/FHIR business models for European digital health research networks (EHDS). | Digital Health / Business Models | RQ2, RQ4 |
| CIDE2 | Explainable Federated Learning for secure telemedicine — privacy-preserving deepfake detection in digital health platforms. | Digital Health / XAI | RQ1, RQ2 |
| FedHR5.0 | Privacy-preserving Federated Learning framework for Human Resource Management in Industry 5.0. | HR / Industry 5.0 | — |
| CRISTAIN2025 | FA-FedAvg — Forensic-Aware Federated Averaging for law enforcement inter-agency collaboration. | Criminal Justice | — |
| Repository | Description | Focus | RQ |
|---|---|---|---|
| AI-DIGOSA | Multidimensional framework analyzing tensions between norms, ethics, and innovation in distributed AI healthcare. | Ethics & Regulation | RQ2, RQ4 |
| icsis2026 | FL as policy data infrastructure for territorial healthcare planning in aging European regions (EHDS). | Health Policy | RQ3, RQ4 |
| ICID2026 | Three-layered reference architecture for deploying FL within EHDS — IDSA, Data Mesh, hierarchical FL. | Architecture & Standards | RQ1, RQ4 |
| Repository | Description | Type | RQ |
|---|---|---|---|
| DHFLPL2 | Foundational paper — MDPI Applied Sciences 2024 (21 citations). Systematized evolution of the FL research platform. | Seminal · P-M | RQ1, RQ3 |
| DHFLPL | Original repo referenced in the published paper (v1). | Legacy · P-M | RQ1, RQ3 |
| Heterogeneous_Federated_Learning | Curated collection of educational materials on heterogeneous FL (2020+). | Educational | RQ1 |
| tesi_fl_2025 | Thesis core repository. | Private | All |
| HFEDL_Project | Heterogeneous FL research project. | Private | RQ1 |
| Code | Title | Venue | Year | Status | Repository |
|---|---|---|---|---|---|
| P-M | Federated Learning in Dynamic and Heterogeneous Environments: Advantages, Performances, and Privacy Problems | MDPI Applied Sciences · DOI | 2024 | Published (21 cit.) | DHFLPL2 · (v1) |
| P-IS | FedHR5.0: Privacy-Preserving HR Management in Industry 5.0 | ISM 2025 — Univ. of Malta | 2025 | Accepted | FedHR5.0 |
| P-CR | FA-FedAvg: Forensic-Aware Federated Averaging for Law Enforcement | CRISTAIN 2025 — CHItaly | 2025 | Accepted | CRISTAIN2025 |
| P-C1 | Transforming Clinical Silos into Economic Assets: Business Models for European Digital Health Research Networks | CIDE 2025 — Ploiesti | 2025 | Presented | CIDE |
| P-C2 | Explainable Federated Learning for Secure Telemedicine: Privacy-Preserving Deepfake Detection | CIDE 2025 — Ploiesti | 2025 | Presented | CIDE2 |
| P-IT | AI Distribuita e Governance Sanitaria: Analisi Multidimensionale delle Tensioni tra Norme, Etica e Innovazione | ITAIS 2025 | 2025 | Presented | AI-DIGOSA |
| FLICS | FL + EHDS Governance Framework: Differential Privacy and Secure Aggregation | FLICS 2026 — Valencia · IEEE | 2026 | Submitted | FL-EHDS-FLICS2026 |
| ICSIS | FL as Policy Data Infrastructure for Territorial Healthcare Planning | ICSIS 2026 — Valencia | 2026 | Submitted | icsis2026 |
| ICID | Three-Layered Reference Architecture for FL within EHDS | ICID 2026 — Ulaanbaatar · Springer | 2026 | Submitted | ICID2026 |
| IFKAD | FedHR5.0: Federated Learning for Knowledge Asset Dynamics in Industry 5.0 | IFKAD 2026 — Budapest | 2026 | Submitted | Repo TBD |
This meta-repository uses Git submodules to link all component repositories.
# Clone with all submodules
git clone --recurse-submodules https://github.com/FabioLiberti/FENITH2.git
# If already cloned, initialize submodules
git submodule update --init --recursive
# Update all submodules to their latest commit
git submodule update --remote --mergeNote: Some submodules (
tesi_fl_2025,HFEDL_Project) are private repositories. Access requires appropriate GitHub permissions.
This work is licensed under CC BY-NC-SA 4.0.
Individual submodules may have their own licenses — refer to each repository for details.
Fabio Liberti PhD Candidate — Universitas Mercatorum, Rome, Italy
This research has been conducted in collaboration with the following institutions:
| Institution | Role | Period |
|---|---|---|
| Universitas Mercatorum — Rome, Italy | PhD Program — Home University | 2023 – present |
| Ospedale Pediatrico Bambino Gesù (OPBG) — Rome, Italy | Research Internship — Clinical FL platforms and healthcare datasets | Oct 2023 – Mar 2025 |
| Blekinge Institute of Technology (BTH) — Karlskrona, Sweden | Research Internship — Heterogeneous FL and international collaboration | Apr 2025 – Sep 2026 |
This PhD research was carried out under the supervision of:
- Prof. Barbara Martini — Universitas Mercatorum (thesis supervisor)
- Prof. Andrea Mazzitelli — Universitas Mercatorum (co-supervisor)
The author gratefully acknowledges the contributions of:
- Prof. Davide Berardi — Universitas Mercatorum, for the collaboration on the foundational Federated Learning research.
- Prof. Alberto Eugenio Tozzi — Ospedale Pediatrico Bambino Gesù, Preventive and Predictive Diseases Research Unit, for the mentorship during the institutional research internship.
- Prof. Sadi Alawadi — Blekinge Institute of Technology (Sweden), for the mentorship during the international research internship.
- All the Italian hospitals that participated in the Federated Learning adoption questionnaire.
federated-learning · european-health-data-space · ehds · privacy-preserving · differential-privacy · secure-aggregation · digital-healthcare-governance · heterogeneous-environments · dynamic-environments · omop-ohdsi · hl7-fhir · data-mesh · industry-5-0

