RL-LIM: Reinforcement Learning-based Locally Interpretable Modeling

Understanding black-box machine learning models is important towards their widespread adoption. However, developing globally interpretable models that explain the behavior of the entire model is challenging. An alternative approach is to explain black-box models through explaining individual prediction using a locally interpretable model. In this paper, we propose a novel method for locally interpretable modeling - Reinforcement Learning-based Locally Interpretable Modeling (RL-LIM). RL-LIM employs reinforcement learning to select a small number of samples and distill the black-box model prediction into a low-capacity locally interpretable model. Training is guided with a reward that is obtained directly by measuring agreement of the predictions from the locally interpretable model with the black-box model. RL-LIM near-matches the overall prediction performance of black-box models while yielding human-like interpretability, and significantly outperforms state of the art locally interpretable models in terms of overall prediction performance and fidelity.Comment: 18 pages, 7 figures, 7 table

Search-Adaptor: Text Embedding Customization for Information Retrieval

Text embeddings extracted by pre-trained Large Language Models (LLMs) have significant potential to improve information retrieval and search. Beyond the zero-shot setup in which they are being conventionally used, being able to take advantage of the information from the relevant query-corpus paired data has the power to further boost the LLM capabilities. In this paper, we propose a novel method, Search-Adaptor, for customizing LLMs for information retrieval in an efficient and robust way. Search-Adaptor modifies the original text embedding generated by pre-trained LLMs, and can be integrated with any LLM, including those only available via APIs. On multiple real-world English and multilingual retrieval datasets, we show consistent and significant performance benefits for Search-Adaptor -- e.g., more than 5.2% improvements over the Google Embedding APIs in nDCG@10 averaged over 13 BEIR datasets.Comment: 9 pages, 2 figure

LANISTR: Multimodal Learning from Structured and Unstructured Data

Multimodal large-scale pretraining has shown impressive performance for unstructured data including language, image, audio, and video. However, a prevalent real-world scenario involves the combination of structured data types (tabular, time-series) with unstructured data which has so far been understudied. To bridge this gap, we propose LANISTR, an attention-based framework to learn from LANguage, Image, and STRuctured data. The core of LANISTR's methodology is rooted in \textit{masking-based} training applied across both unimodal and multimodal levels. In particular, we introduce a new similarity-based multimodal masking loss that enables it to learn cross-modal relations from large-scale multimodal data with missing modalities. On two real-world datastes, MIMIC-IV (healthcare) and Amazon Product Review (retail), LANISTR demonstrates remarkable absolute improvements of 6.6\% (AUROC) and up to 14\% (accuracy) when fine-tuned on 0.1\% and 0.01\% of labeled data, respectively, compared to the state-of-the-art alternatives. Notably, these improvements are observed even in the presence of considerable missingness ratios of 35.7\% and 99.8\%, in the respective datasets