Chronocept: Instilling a Sense of Time in Machines

Human cognition is deeply intertwined with a sense of time, known as Chronoception. This sense allows us to judge how long facts remain valid and when knowledge becomes outdated. Despite progress in vision, language, and motor control, AI still struggles to reason about temporal validity. We introduce Chronocept, the first benchmark to model temporal validity as a continuous probability distribution over time. Using skew-normal curves fitted along semantically decomposed temporal axes, Chronocept captures nuanced patterns of emergence, decay, and peak relevance. It includes two datasets: Benchmark I (atomic facts) and Benchmark II (multi-sentence passages). Annotations show strong inter-annotator agreement (84% and 89%). Our baselines predict curve parameters - location, scale, and skewness - enabling interpretable, generalizable learning and outperforming classification-based approaches. Chronocept fills a foundational gap in AI's temporal reasoning, supporting applications in knowledge grounding, fact-checking, retrieval-augmented generation (RAG), and proactive agents. Code and data are publicly available.

HIRO: Hierarchical Information Retrieval Optimization

Large Language Models (LLMs) excel in natural language tasks but face limitations due to static training datasets, resulting in outdated or contextually shallow responses. Retrieval-Augmented Generation (RAG) addresses this by integrating real-time external knowledge, enhancing model accuracy and credibility, especially for knowledge-intensive tasks. However, RAG-enhanced LLMs struggle with long contexts, causing them to "choke" on information overload, compromising response quality. Recent RAG applications use hierarchical data structures for storing documents, organized at various levels of summarization and information density. In this context, we introduce HIRO (Hierarchical Information Retrieval Optimization), a novel querying approach for RAG applications using hierarchical structures for storing documents. HIRO employs DFS-based recursive similarity score calculation and branch pruning to minimize the context returned to the LLM without informational loss. HIRO outperforms existing querying mechanisms on the NarrativeQA dataset by an absolute performance gain of 10.85%.