arXiv subjects

Eva Bartz

Publications and source records attributed to Eva Bartz.

6 recordsLinked to original sources

arXiv2026

Time-Series Forecasting in Safety-Critical Environments: An Open-Source Package for EU-AI-Act-Compliant Development / Zeitreihenprognose in sicherheitskritischen Umgebungen: Ein Open-Source-Paket f\"ur die KI-VO-konforme Entwicklung

With spotforecast2-safe we present an integrated Compliance-by-Design approach to Python-based point forecasting of time series in safety-critical environments. A review of the relevant open-source tooling shows that existing compliance solutions operate consistently outside of the library to be used - e.g. as scanners, templates, or runtime layers. spotforecast2-safe takes the inverse approach and anchors the requirements of Regulation (EU) 2024/1689 (the EU AI Act, in German: KI-VO), of IEC 61508, of the ISA/IEC 62443 standards series, and of the Cyber Resilience Act within the library: in application-programming-interface contracts, persistence formats, and continuous-integration gates. The approach is operationalised by four non-negotiable code-development rules (zero dead code, deterministic processing, fail-safe handling, minimal dependencies) together with the corresponding process rules (model card, executable docstrings, CI workflows, Common-Platform-Enumeration (CPE) identifier, REUSE-conformant licensing, release pipeline). Interactive visualisation, hyperparameter tuning and automated machine learning (AutoML), as well as deep-learning and large-language-model backends are deliberately excluded, because each of these components either enlarges the attack surface, introduces non-determinism, or impairs reproducibility. Every article of the EU AI Act that is relevant to the library is discussed in detail. A bidirectional traceability matrix maps every regulatory provision onto the corresponding mechanism in the code; an end-to-end example of European-market electricity generation, transmission, and consumption forecasting demonstrates the application. The package is open-source and available under Affero General Public License (AGPL) 3.0-or-later.

cs.AI↗

arXiv2025

Multi-Objective Optimization with Desirability and Morris-Mitchell Criterion

Industrial experimental designs frequently lack optimal space-filling properties, rendering them unrepresentative. This study presents a comprehensive methodology to refine existing designs by enhancing coverage quality while optimizing experimental outcomes. We discuss and analyse variants of the Morris-Mitchell criterion to quantify and improve spatial distributions. Based on potential theory, we analyze monotonicity properties and limitations of the Morris-Mitchell criteria. Practically, we implement a multi-objective optimization framework utilizing the Python packages spotdesirability and spotoptim. This framework uses desirability functions to combine surrogate-model predictions with space-filling enhancements into a unified score. Demonstrated through data from a compressor development case study, this approach optimizes performance objectives alongside design coverage. To facilitate implementation, we introduce novel infill-point diagnostics that visually guide the sequential placement of design points. This integrated methodology successfully bridges spatial theory with engineering application, balancing the crucial exploration and exploitation trade-off.

math.OC↗

arXiv2021

Experimental Investigation and Evaluation of Model-based Hyperparameter Optimization

Machine learning algorithms such as random forests or xgboost are gaining more importance and are increasingly incorporated into production processes in order to enable comprehensive digitization and, if possible, automation of processes. Hyperparameters of these algorithms used have to be set appropriately, which can be referred to as hyperparameter tuning or optimization. Based on the concept of tunability, this article presents an overview of theoretical and practical results for popular machine learning algorithms. This overview is accompanied by an experimental analysis of 30 hyperparameters from six relevant machine learning algorithms. In particular, it provides (i) a survey of important hyperparameters, (ii) two parameter tuning studies, and (iii) one extensive global parameter tuning study, as well as (iv) a new way, based on consensus ranking, to analyze results from multiple algorithms. The R package mlr is used as a uniform interface to the machine learning models. The R package SPOT is used to perform the actual tuning (optimization). All additional code is provided together with this paper.

cs.LG↗

arXiv2020

Hospital Capacity Planning Using Discrete Event Simulation Under Special Consideration of the COVID-19 Pandemic

We present a resource-planning tool for hospitals under special consideration of the COVID-19 pandemic, called babsim.hospital. It provides many advantages for crisis teams, e.g., comparison with their own local planning, simulation of local events, simulation of several scenarios (worst / best case). There are benefits for medical professionals, e.g, analysis of the pandemic at local, regional, state and federal level, the consideration of special risk groups, tools for validating the length of stays and transition probabilities. Finally, there are potential advantages for administration, management, e.g., assessment of the situation of individual hospitals taking local events into account, consideration of relevant resources such as beds, ventilators, rooms, protective clothing, and personnel planning, e.g., medical and nursing staff. babsim.hospital combines simulation, optimization, statistics, and artificial intelligence processes in a very efficient way. The core is a discrete, event-based simulation model.

stat.AP↗

arXiv2020

Optimization of High-dimensional Simulation Models Using Synthetic Data

Simulation models are valuable tools for resource usage estimation and capacity planning. In many situations, reliable data is not available. We introduce the BuB simulator, which requires only the specification of plausible intervals for the simulation parameters. By performing a surrogate-model based optimization, improved simulation model parameters can be determined. Furthermore, a detailed statistical analysis can be performed, which allows deep insights into the most important model parameters and their interactions. This information can be used to screen the parameters that should be further investigated. To exemplify our approach, a capacity and resource planning task for a hospital was simulated and optimized. The study explicitly covers difficulties caused by the COVID-19 pandemic. It can be shown, that even if only limited real-world data is available, the BuB simulator can be beneficially used to consider worst- and best-case scenarios. The BuB simulator can be extended in many ways, e.g., by adding further resources (personal protection equipment, staff, pharmaceuticals) or by specifying several cohorts (based on age, health status, etc.). Keywords: Synthetic data, discrete-event simulation, surrogate-model-based optimization, COVID-19, machine learning, artificial intelligence, hospital resource planning, prediction tool, capacity planning.

stat.AP↗

arXiv2019

Why we need an AI-resilient society- Profiling Large Language Models

Three generations of software have transformed the role of artificial intelligence in society. In the first, programmers wrote explicit logic. In the second, neural networks learned programs from data. In the third, large language models turn natural language itself into a programming interface. These shifts reach far beyond computer science, reshaping how societies generate knowledge, make decisions, and govern themselves. While generative adversarial networks introduced the era of deepfakes and synthetic media, large language models have added a new class of systemic risks. This report performs "mindhunting" for LLMs by applying a forensic-psychology profiling methodology to characterize AI based on documented features, e.g., hallucinations, bias and toxicity, sycophancy, fabrication and confabulation, knowledge without understanding, discontinuity and the inability to learn from experience, jagged intelligence, shortcuts and fractured representations. The resulting profile reveals an "entity" that confabulates fluently, amplifies its users' biases, possesses encyclopedic recall without causal understanding, and erodes the competence of those who depend on it. The implications extend to institutional erosion across law, academia, journalism, and democratic governance. To address these challenges, this report proposes a four-pillar framework for AI resilience: (i) cognitive sovereignty, which preserves the capacity for independent judgment, (ii) measurable control, which translates ethical commitments into enforceable standards and red lines, (iii) partial autonomy, which maintains human agency at critical decision points, and (iv) openness to guarantee transparency and accessibility (open-source, open-access, and open-data). This report is an updated and extended version of arXiv:1912.08786v1.

cs.CY↗