National Technical University of Athens

Beyond task success: domain-grounded evaluation of Earth-observation agents in environmental risk workflows

AI agents now run Earth observation (EO) workflows end to end, and their authors judge them on the task: answer accuracy, tool use, report scores and case studies. None of these evaluations asks whether the agent acted on a bad input. We ran five published EO and climate agents (...

LLM-Orchestrated Evasion of Tabular NIDS and GAN Augmentation for Multimodal Detection

Network Intrusion Detection Systems (NIDSs) based on machine learning have demonstrated strong performance against known attack patterns. However, their robustness against adaptive evasion strategies orchestrated by modern Large Language Models (LLMs) remains largely unexplored....

On the benefits of temporal aggregation on forecasting and stock control: empirical evidence from statistical and machine learning methods

The ADIDA forecasting approach broke into the operational research literature in 2011, originally as a method for intermittent demand forecasting; 15 years and 226 citations later, with applications spanning from normal and intermittent to hierarchical demand, and inspiring the c...

A Unified Scalar-Field Mechanism for the H0, S8 and Evolving Dark-Energy Tensions

I investigate whether one minimally coupled canonical scalar field can generate, in a single continuous cosmological history, the correlated changes in the sound horizon, late-time expansion, and structure growth that are relevant to the H0, evolving dark-energy, and S8 tensions....

Development and application of a methodological framework for assessing the resilience of military infrastructure against climate change impacts

Mitigating climate change impacts and enhancing the resilience capacity of military infrastructure is essential for the Armed Forces, first, to ensure a high level of both readiness and sustainability transitions and, second, to contribute to each European Union Member-State’s (E...

Optimal inertia allocation in networked DC microgrids with guaranteed steady-state and small-signal stability

DC microgrids (MGs) are considered an efficient solution for integrating distributed energy sources. In these networks during dynamic power imbalances, the stored energy in the capacitor of DC bus provides the natural tendency to resist voltage changes, equivalent to the physical...

Influence of nonlinear Lysmer dashpots on seismic soil-structure interaction: a comparative finite element study

Abstract In the present study, the influence of nonlinear Lysmer dashpots on seismic soil structure interaction is investigated using three dimensional hexahedral finite element models. Nonlinear Lysmer absorbing boundaries are compared with free and fixed boundaries under seismi...

A beam-down linear Fresnel reflector integrated with photovoltaics for combined heat and electricity production

A beam-down linear Fresnel reflector coupled with a flat plate receiver and photovoltaics is designed and investigated in optical and thermal terms. The secondary reflector has a triangular shape both for increased efficiency and potentially reduced construction cost, which is a...

Vision-AI-driven dilemma zone modelling for driver behaviour prediction

Driver behaviour in the dilemma zone critically influences red-light violations and intersection safety. This study presents a scalable Vision-AI and deep learning framework modelling driver decisions based on vehicle type, speed, acceleration, lane occupation, and signal distanc...

Disjunctive Programming and Piecewise Convexity: An Algorithmic Trajectory Analysis Toward Stationary Points to Avoid the Maratos Effect in Numerical Optimization

In this paper, we present an algorithmic modeling approach based on Disjunctive Programming using Boolean logic “OR” to solve the Optimal Phasor Measurement Unit Placement (OPP). We propose a framework for modeling the optimal PMU placement subject to disjunctive constraints. A c...

Hydromechanical Behaviour of Intact and Recompacted Crushed Caprock for Underground CO2 Storage

Abstract This work investigates the hydromechanical behaviour of Opalinus Clay (OPA) shale as a caprock material for geological storage of CO $$_2$$ 2 . In addition to intact OPA, the hydromechanical response of crushed material is evaluated to simulate damaged zones around injec...

Modelling hydroelastic flexure of arbitrarily shaped ice shelves forced by long ocean waves

Flexure of Antarctic ice shelves under excitation from long ocean waves induces mechanical ice-shelf stresses that amplify fractures and, hence, contribute to calving events. Here, a solution method is developed for a hydroelastic mathematical model of wave-induced ice-shelf flex...

Artificial Intelligence in Support of National Land Administration and Build-Back-Better Policies: A Technical and Policy Assessment of the Hellenic Cadastre and the Cross-Sectoral Reuse of Geospatial Infrastructure (HEPOS)

In April 2024, the Hellenic Cadastre became one of Europe’s first land registries to use a generative AI model (a large language model served through Azure OpenAI) for the legal review of property deeds. Unlike similar European initiatives using classical NLP, Greece applied stat...

Network-Level Traffic and Safety Effects of Automated Vehicle Market Penetration Under Take-Over Events: A Microsimulation Study

This study investigates the network-level traffic and safety effects of increasing Market Penetration Rate (MPR) of SAE Level 2 and Level 3 automated vehicles under take-over conditions. A calibrated microsimulation model of a real-world 50 km highway corridor in Greece (Nea Odos...

Machine-Generated, Machine-Checked Proofs for a Verified Compiler (Experience Report)

We report on using an agentic coding assistant (Claude Code, powered by Claude Opus 4.6) to mechanize a substantial Rocq correctness proof from scratch, with human guidance but without any human-authored proof code. The proof establishes semantic preservation for the administrati...

The emergence of (3+1)-dimensional expanding spacetime from complex Langevin simulations of the Lorentzian type IIB matrix model with deformations

Abstract The Lorentzian type IIB matrix model is a promising candidate for a nonperturbative formulation of superstring theory. In this model, the eigenvalue distribution of the N × N bosonic matrices Aμ (μ = 0, …, 9) represents an emergent spacetime, which is determined by the d...

Aquaplaning Mitigation via Longitudinal Crown Lines

As climate change drives more frequent and intense rainfall events worldwide, urban areas are increasingly vulnerable to flooding—an issue further amplified by rapid urbanization and industrialization. In this context, aquaplaning has become a critical consideration in road desig...

Infectious complications following bispecific antibody or CAR T therapy in adult patients with hematologic malignancies: a retrospective database analysis

T-cell redirection therapies, including bispecific antibodies (BsAbs) and chimeric antigen receptor (CAR) T therapy, have transformed the treatment of relapsed or refractory hematologic malignancies. However, comparative data on infectious complications between these treatments r...

Wave Scattering and Hydrodynamic Interaction Effects Among the Columns of the OC4-DeepCwind Semi-Submersible Floating Offshore Wind Turbine

This study investigates the hydrodynamic behavior of the OC4-DeepCwind floating offshore wind turbine, with a specific focus on the influence of wave reflection and hydrodynamic interaction effects between the platform components. The OC4-DeepCwind semi-submersible platform, supp...

The hydrogeological and tectonic features as the crucial factors for the hydro-geochemistry of surface and groundwater in active geothermal systems: The case study of Methana Peninsula in Greece

Abstract Active geothermal systems developed in coastal volcanic environments are characterized by complex interactions among magmatic fluids, groundwater, seawater, and structurally controlled permeability. The Methana Peninsula (western Hellenic Volcanic Arc, Greece) represents...