← Search

Stratis Tsirtsis

6 accepted papers

2026

Is Your LLM Overcharging You? Tokenization, Transparency, and Incentives

ICML 2026oral

State-of-the-art large language models require specialized hardware and substantial energy to operate. Consequently, cloud-based services that provide access to these models have become very popular. In these services, the price users pay depends on the number of tokens a model uses to generate an o…

Cited by 0SourcecodeScholar
2026

The Heterogeneous Safety Impacts of Benign Multilingual Fine-Tuning

ICML 2026poster

Fine-tuning a large language model is a ubiquitous method for enhancing its capability on a specific downstream task. However, prior work has shown that this increase in capability comes with a cost: it can increase a model's tendency to respond to unsafe adversarial prompts, even when fine-tuning w…

Cited by 0SourceScholar
2023

Finding Counterfactually Optimal Action Sequences in Continuous State Spaces

NeurIPS 2023poster

Whenever a clinician reflects on the efficacy of a sequence of treatment decisions for a patient, they may try to identify critical time steps where, had they made different decisions, the patient's health would have improved. While recent methods at the intersection of causal inference and reinforc…

2023

On the Within-Group Fairness of Screening Classifiers

ICML 2023poster

Screening classifiers are increasingly used to identify qualified candidates in a variety of selection processes. In this context, it has been recently shown that if a classifier is calibrated, one can identify the smallest set of candidates which contains, in expectation, a desired number of qualif…

2021

Counterfactual Explanations in Sequential Decision Making Under Uncertainty

NeurIPS 2021poster

Methods to find counterfactual explanations have predominantly focused on one-step decision making processes. In this work, we initiate the development of methods to find counterfactual explanations for decision making processes in which multiple, dependent actions are taken sequentially over time.…

2020

Decisions, Counterfactual Explanations and Strategic Behavior

NeurIPS 2020poster

As data-driven predictive models are increasingly used to inform decisions, it has been argued that decision makers should provide explanations that help individuals understand what would have to change for these decisions to be beneficial ones. However, there has been little discussion on the possi…