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Helsinki Institute for Information Technology

Academic institutioneurope · fi
Official website
Research library8linked papers
Opportunities0open roles
Selected work

Representative Papers

Wheeler Bisimulations

Feb 08, 2026

This work addresses the lack of efficient minimization techniques for nondeterministic Wheeler automata, which stems from the absence of a suitable equivalence relation preserving their structural properties. We introduce the novel notion of *Wheeler bisimulation*, an equivalence relation that maintains the convex structure inherent to Wheeler automata, and establish—for the first time—a unique minimal form for Wheeler NFAs. Leveraging this relation, we design a linear-time algorithm that constructs the minimal Wheeler NFA in $O(m)$ time, substantially improving upon the $O(m \log n)$ complexity of conventional bisimulation-based approaches. Our results provide both theoretical foundations and practical algorithms for the efficient processing of Wheeler languages.

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CurricuLLM: Designing Personalized and Workforce-Aligned Cybersecurity Curricula Using Fine-Tuned LLMs

Jan 08, 2026arXiv.org

This study addresses the high cost and slow iteration of cybersecurity curriculum design, which often results in a misalignment between graduates’ competencies and rapidly evolving industry skill demands. To bridge this gap, the authors propose CurricuLLM, a novel framework that leverages fine-tuned large language models for automated curriculum development. The approach first standardizes input data using PreprocessLM, then employs a fine-tuned BERT model (ClassifyLM) to accurately categorize course content into nine established knowledge domains. By integrating job-market weightings, the system dynamically generates personalized, labor-market-aligned curricula. An expert validation mechanism further enhances both the efficiency of curriculum development and its relevance to industry needs. CurricuLLM thus offers a scalable and customizable intelligent solution for modern cybersecurity education.

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Scalable Domain-decomposed Monte Carlo Neutral Transport for Nuclear Fusion

Nov 06, 2025

The EIRENE Monte Carlo neutral transport solver lacks domain decomposition capability, suffering from severe single-node memory bottlenecks when handling ultra-large-scale meshes. Method: This work proposes and implements a Domain-Decomposed Monte Carlo (DDMC) algorithm—integrating scalable domain decomposition with neutral particle transport modeling for the first time—and embeds it within the open-source Eiron framework. Contribution/Results: The DDMC algorithm achieves strong scalability beyond linear scaling and large-scale weak scalability: on the Mahti supercomputer, it demonstrates weak scaling up to 16,384 cores, attaining 45% and 26% parallel efficiency for high- and low-collision regimes, respectively. It overcomes memory limitations, enabling previously infeasible large-scale fusion simulations. Compared to the native EIRENE algorithm, DDMC significantly improves parallel efficiency and extends the tractable problem size, establishing a scalable, high-performance computing paradigm for fusion boundary physics simulation.

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Characterizing Small Circuit Classes from FAC^0 to FAC^1 via Discrete Ordinary Differential Equations

Jun 29, 2025

This paper investigates algebraic characterizations and complexity bounds for small Boolean circuit classes—specifically FAC⁰, FAC¹, FACC[2], and FNC¹. We introduce a unified framework based on discrete ordinary differential equations (ODEs), establishing the first exact correspondence between circuit computational power and linear-length ODE constraints: function linearity, bounded derivatives, and controlled growth rates. Our method yields ODE-completeness characterizations for FACC[2] (circuits with Mod₂ gates) and FNC¹ (log-depth circuits), delivering tight algebraic representations for multiple circuit classes. Crucially, we uncover the structural role of counting mechanisms in circuit computation, revealing how modular counting underpins separations among low-level complexity classes. These results provide novel analytical tools and potential pathways toward resolving longstanding open problems, such as the separation of FAC⁰ from FAC¹.

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Fair Diversity Maximization with Few Representatives

Jun 09, 2025

This paper studies the fairness-constrained diversity maximization problem: selecting $k$ representative points from a multi-label dataset such that at most a constant number of samples is chosen from each label class, while maximizing the minimum pairwise distance. For small-scale cross-group representative selection, we propose the first three-stage framework—pre-pruning, padded decomposition, and label-aware assignment. We introduce a distance-driven pre-pruning step to improve efficiency; employ randomized padded decomposition to balance intra-group sparsity and global diversity; and design a label-aware cluster assignment mechanism to ensure fair label coverage. We theoretically establish an approximation ratio of $Omega(sqrt{log m}/m)$, significantly improving upon prior methods. Experiments on large-scale datasets demonstrate that our approach achieves state-of-the-art performance in both minimum pairwise distance and label coverage, while strictly satisfying fairness constraints.

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Recent publications

Latest Papers

Wheeler Bisimulations

Feb 08, 2026

This work addresses the lack of efficient minimization techniques for nondeterministic Wheeler automata, which stems from the absence of a suitable equivalence relation preserving their structural properties. We introduce the novel notion of *Wheeler bisimulation*, an equivalence relation that maintains the convex structure inherent to Wheeler automata, and establish—for the first time—a unique minimal form for Wheeler NFAs. Leveraging this relation, we design a linear-time algorithm that constructs the minimal Wheeler NFA in $O(m)$ time, substantially improving upon the $O(m \log n)$ complexity of conventional bisimulation-based approaches. Our results provide both theoretical foundations and practical algorithms for the efficient processing of Wheeler languages.

0 citationsRead paper

CurricuLLM: Designing Personalized and Workforce-Aligned Cybersecurity Curricula Using Fine-Tuned LLMs

Jan 08, 2026arXiv.org

This study addresses the high cost and slow iteration of cybersecurity curriculum design, which often results in a misalignment between graduates’ competencies and rapidly evolving industry skill demands. To bridge this gap, the authors propose CurricuLLM, a novel framework that leverages fine-tuned large language models for automated curriculum development. The approach first standardizes input data using PreprocessLM, then employs a fine-tuned BERT model (ClassifyLM) to accurately categorize course content into nine established knowledge domains. By integrating job-market weightings, the system dynamically generates personalized, labor-market-aligned curricula. An expert validation mechanism further enhances both the efficiency of curriculum development and its relevance to industry needs. CurricuLLM thus offers a scalable and customizable intelligent solution for modern cybersecurity education.

0 citationsRead paper

Scalable Domain-decomposed Monte Carlo Neutral Transport for Nuclear Fusion

Nov 06, 2025

The EIRENE Monte Carlo neutral transport solver lacks domain decomposition capability, suffering from severe single-node memory bottlenecks when handling ultra-large-scale meshes. Method: This work proposes and implements a Domain-Decomposed Monte Carlo (DDMC) algorithm—integrating scalable domain decomposition with neutral particle transport modeling for the first time—and embeds it within the open-source Eiron framework. Contribution/Results: The DDMC algorithm achieves strong scalability beyond linear scaling and large-scale weak scalability: on the Mahti supercomputer, it demonstrates weak scaling up to 16,384 cores, attaining 45% and 26% parallel efficiency for high- and low-collision regimes, respectively. It overcomes memory limitations, enabling previously infeasible large-scale fusion simulations. Compared to the native EIRENE algorithm, DDMC significantly improves parallel efficiency and extends the tractable problem size, establishing a scalable, high-performance computing paradigm for fusion boundary physics simulation.

0 citationsRead paper

Characterizing Small Circuit Classes from FAC^0 to FAC^1 via Discrete Ordinary Differential Equations

Jun 29, 2025

This paper investigates algebraic characterizations and complexity bounds for small Boolean circuit classes—specifically FAC⁰, FAC¹, FACC[2], and FNC¹. We introduce a unified framework based on discrete ordinary differential equations (ODEs), establishing the first exact correspondence between circuit computational power and linear-length ODE constraints: function linearity, bounded derivatives, and controlled growth rates. Our method yields ODE-completeness characterizations for FACC[2] (circuits with Mod₂ gates) and FNC¹ (log-depth circuits), delivering tight algebraic representations for multiple circuit classes. Crucially, we uncover the structural role of counting mechanisms in circuit computation, revealing how modular counting underpins separations among low-level complexity classes. These results provide novel analytical tools and potential pathways toward resolving longstanding open problems, such as the separation of FAC⁰ from FAC¹.

0 citationsRead paper

Fair Diversity Maximization with Few Representatives

Jun 09, 2025

This paper studies the fairness-constrained diversity maximization problem: selecting $k$ representative points from a multi-label dataset such that at most a constant number of samples is chosen from each label class, while maximizing the minimum pairwise distance. For small-scale cross-group representative selection, we propose the first three-stage framework—pre-pruning, padded decomposition, and label-aware assignment. We introduce a distance-driven pre-pruning step to improve efficiency; employ randomized padded decomposition to balance intra-group sparsity and global diversity; and design a label-aware cluster assignment mechanism to ensure fair label coverage. We theoretically establish an approximation ratio of $Omega(sqrt{log m}/m)$, significantly improving upon prior methods. Experiments on large-scale datasets demonstrate that our approach achieves state-of-the-art performance in both minimum pairwise distance and label coverage, while strictly satisfying fairness constraints.

0 citationsRead paper