Joaquin Vanschoren

Author directory

2026

Time series analysis in high-stakes domains relies on recurring data releases, where new observations can alter the evidence base and the validity of later conclusions. Existing time series QA benchmarks mostly rely on fixed snapshots, leaving temporal validity and cutoff-aware evidence use unevaluated. We introduce TimeSage-EV, a live benchmark for agentic time series analysis in evolving environments. It tracks 60 real institutional scenarios across 6 domains, comprising 1,485 scenario-period QA pairs from Feb 2023 to May 2026 and spanning monthly, weekly, daily, and irregular release cadences. At each period, large language model (LLM) agents receive time series data and source reports, while the withheld target release provides ground truth. TimeSage-EV evaluates state identification, data summarization, and outlook reasoning. Experiments with frontier LLM agents and TimeSage-1.0, a novel self-evolving agent with a reusable analytical skill library, reveal significant performance gaps across model tiers and recurring failures in temporal validity, exogenous context use, and adaptation. We release TimeSage-EV as a research resource with monthly updates, code, a leaderboard, and failure-mode analyses.
In few-shot learning, the selection of samples has a significant impact on the performance of the model. While effective sample selection strategies are well-established in supervised settings, research on large language models largely overlooks them, favouring strategies specifically tailored to individual in-context learning settings. In this paper, we propose a new method for Automatic Combination of SamplE Selection Strategies (ACSESS) to leverage the strengths and complementarity of various well-established selection objectives. We investigate and compare the impact of 23 sample selection strategies on the performance of 5 in-context learning models and 3 few-shot learning approaches (meta-learning, few-shot fine-tuning) over 6 text and 8 image datasets. The experimental results show that the combination of strategies through the ACSESS method consistently outperforms all individual selection strategies and performs on par or exceeds the in-context learning specific baselines. Lastly, we demonstrate that sample selection remains effective even on smaller datasets, yielding the greatest benefits when only a few shots are selected, while its advantage diminishes as the number of shots increases.
Speculative decoding has emerged as a promising approach to accelerate Large Language Model inference. However, existing research has predominantly focused on 7B-70B parameters models, leaving a critical knowledge gap for small language models (1-2B parameters) that are increasingly important for edge computing and agentic AI systems. This paper presents the first comprehensive empirical study of speculative decoding techniques for small language models. We evaluate five distinct method categories across three representative model families and reveal that drafting overhead, rather than draft quality, becomes the primary bottleneck fundamentally limiting acceleration of small models. We demonstrate that traditional independent drafting fails completely due to the suboptimal architecture of available drafters, while self-drafting methods achieve meaningful acceleration only when employing sufficiently efficient draft modules. In contrast, retrieval-based methods with negligible computational overhead yield consistent gains. Based on these insights, we establish practical guidelines for effective small model acceleration.