Hemant Purohit

Author directory

2026

In this paper, we evaluate three state-of-the-art (SOTA) MM-LLMs on consistency of their outputs across text and audio modalities using real emergency alerts. Building on prior semantic-similarity and factual-overlap evaluation, we introduce a LIWC aligned analysis of modality dependent differences in linguistic structure, interpersonal framing, urgency, risk, and action-oriented language. Our findings indicate that despite being unified models, capable of taking in input from different modalities, no single model was able to achieve reliable cross-modal consistency. Persona-level results further indicate that cross-modal disparities vary across user groups. This introduces modality dependent inequity that unfairly affects individuals with access and functional needs. We release prompts, audio recordings, model outputs and evaluation material to support the crisis language technology community in building equitable solution for crisis management.
When a disaster strikes, question-answering (QA) systems promise to turn scattered satellite, infrastructure, and hazard impact data into actionable answers for coordinators working under time pressure. But how critically should we trust those answers, even if grounded in the background knowledge? We present RISE, a prototype knowledge-graph (KG)-powered QA system built on data from the June 2026 Venezuela M7.5 earthquake, and subject it to a critical evaluation. Two complementary studies run on the same 30 questions: a stage-wise trace records how each question moves through the pipeline, while an independent LLM-as-a-judge assessment scores the final answer on five language-quality criteria. Taken separately, both studies suggest a system that works: 87% intent accuracy, every question answered, and judge scores averaging above 4 out of 5. Albeit together, they reveal a different picture. Intent misclassifications trace to a linguistic ambiguity no keyword-based classifier can resolve: the same word serves as context in one question and as the information need in another, and lexical matching cannot tell them apart. High scores on grounding and appropriateness do not distinguish a correct answer from a fluent, well-cited answer to the wrong question, because the rubric scores the text against its evidence rather than against the question. Both findings share a common lesson for responsible AI in disaster management to design and develop effective support systems: fluent, well-grounded language by the AI agent is not evidence of a correct answer, and evaluating these systems on their text alone is not enough.

2021

Predicting user intent and detecting the corresponding slots from text are two key problems in Natural Language Understanding (NLU). Since annotated datasets are only available for a handful of languages, our work focuses particularly on a zero-shot scenario where the target language is unseen during training. In the context of zero-shot learning, this task is typically approached using representations from pre-trained multilingual language models such as mBERT or by fine-tuning on data automatically translated into the target language. We propose a novel method which augments monolingual source data using multilingual code-switching via random translations, to enhance generalizability of large multilingual language models when fine-tuning them for downstream tasks. Experiments on the MultiATIS++ benchmark show that our method leads to an average improvement of +4.2% in accuracy for the intent task and +1.8% in F1 for the slot-filling task over the state-of-the-art across 8 typologically diverse languages. We also study the impact of code-switching into different families of languages on downstream performance. Furthermore, we present an application of our method for crisis informatics using a new human-annotated tweet dataset of slot filling in English and Haitian Creole, collected during the Haiti earthquake.

2018

Ever increasing ransomware attacks and thefts of intellectual property demand cybersecurity solutions to protect critical documents. One emerging solution is to place fake text documents in the repository of critical documents for deceiving and catching cyber attackers. We can generate fake text documents by obscuring the salient information in legit text documents. However, the obscuring process can result in linguistic inconsistencies, such as broken co-references and illogical flow of ideas across the sentences, which can discern the fake document and render it unbelievable. In this paper, we propose a novel method to generate believable fake text documents by automatically improving the linguistic consistency of computer-generated fake text. Our method focuses on enhancing syntactic cohesion and semantic coherence across discourse segments. We conduct experiments with human subjects to evaluate the effect of believability improvements in distinguishing legit texts from fake texts. Results show that the probability to distinguish legit texts from believable fake texts is consistently lower than from fake texts that have not been improved in believability. This indicates the effectiveness of our method in generating believable fake text.