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Georgios Kollias

13 accepted papers

2025

EpMAN: Episodic Memory AttentioN for Generalizing to Longer Contexts

ACL 2025long

Recent advances in Large Language Models (LLMs) have yielded impressive successes on many language tasks. However, efficient processing of long contexts using LLMs remains a significant challenge. We introduce **EpMAN** – a method for processing long contexts in an episodic memory module while holis…

2025

Large Language Models can Become Strong Self-Detoxifiers

ICLR 2025poster

Reducing the likelihood of generating harmful and toxic output is an essential task when aligning large language models (LLMs). Existing methods mainly rely on training an external reward model (i.e., another language model) or fine-tuning the LLM using self-generated data to influence the outcome.…

Cited by 0SourcePDFScholar
2025

Multi-Sense Embeddings for Language Models and Knowledge Distillation

ACL 2025finding

Transformer-based large language models (LLMs) rely on contextual embeddings which generate different (continuous) representations for the same token depending on its surrounding context. Nonetheless, words and tokens typically have a limited number of senses (or meanings). We propose multi-sense em…

Cited by 0SourcePDFScholar
2024

Asynchronous Randomized Trace Estimation

AISTATS 2024poster

Randomized trace estimation is a popular technique to approximate the trace of an implicitly-defined matrix $A$ by averaging the quadratic form $x’Ax$ across several samples of a random vector $x$. This paper focuses on the application of randomized trace estimators on asynchronous computing environ…

Cited by 3SourcePDFScholar
2024

Larimar: Large Language Models with Episodic Memory Control

ICML 2024poster

Efficient and accurate updating of knowledge stored in Large Language Models (LLMs) is one of the most pressing research challenges today. This paper presents Larimar - a novel, brain-inspired architecture for enhancing LLMs with a distributed episodic memory. Larimar's memory allows for dynamic, on…

2024

Learning Granger Causality from Instance-wise Self-attentive Hawkes Processes

AISTATS 2024poster

We address the problem of learning Granger causality from asynchronous, interdependent, multi-type event sequences. In particular, we are interested in discovering instance-level causal structures in an unsupervised manner. Instance-level causality identifies causal relationships among individual ev…

Cited by 2SourcePDFScholar
2024

NeuroPrune: A Neuro-inspired Topological Sparse Training Algorithm for Large Language Models

ACL 2024findings

Transformer-based Language Models have become ubiquitous in Natural Language Processing (NLP) due to their impressive performance on various tasks. However, expensive training as well as inference remains a significant impediment to their widespread applicability. While enforcing sparsity at various…

Cited by 2SourcePDFScholar
2023

Accelerating Matrix Trace Estimation by Aitken's Δ2 Process

ICASSP 2023accepted

We present an algorithm to estimate the trace of symmetric matrices that are available only via Matrix-Vector multiplication. The proposed algorithm constructs a series of trace estimates by applying the probing technique with an increasing number of vectors. These estimates are then treated as a co…

Cited by 0SourceScholar
2023

Direction Aware Positional and Structural Encoding for Directed Graph Neural Networks

ICASSP 2023accepted

We propose a novel method for computing joint 2-node structural representations for link prediction in directed graphs. Existing approaches can be grouped into two families. The first group of methods learn structural embeddings of individual nodes in the entire graph through a directed Graph Neural…

Cited by 0SourceScholar
2022

Directed Graph Auto-Encoders

AAAI 2022technical

We introduce a new class of auto-encoders for directed graphs, motivated by a direct extension of the Weisfeiler-Leman algorithm to pairs of node labels. The proposed model learns pairs of interpretable latent representations for the nodes of directed graphs, and uses parameterized graph convolution…

2021

Cardinality-Regularized Hawkes-Granger Model

NeurIPS 2021poster

We propose a new sparse Granger-causal learning framework for temporal event data. We focus on a specific class of point processes called the Hawkes process. We begin by pointing out that most of the existing sparse causal learning algorithms for the Hawkes process suffer from a singularity in maxim…

2021

Projection techniques to update the truncated SVD of evolving matrices with applications

ICML 2021spotlight

This submission considers the problem of updating the rank-$k$ truncated Singular Value Decomposition (SVD) of matrices subject to the addition of new rows and/or columns over time. Such matrix problems represent an important computational kernel in applications such as Latent Semantic Indexing and…