Jan Švec


2026

Documents related to the Holocaust increasingly move into the focus of Natural Language Processing research, including the digitization of written text, the automatic transcription of oral archives, and interpretive downstream tasks such as Named Entity Recognition. However, most modern language models are trained primarily on modern text, and thus struggle with historical language, historical entities, and domain-specific terminology. Furthermore, transcribed speech introduces challenges such as transcription errors, noise, filler words, and dialectal speech not often contained in textual datasets. We present XLM-RoBERTa-malach, a text encoder domain-adapted to oral testimonies of Holocaust survivors in seven languages. In addition to descriptions of the data acquisition via Automatic Speech Recognition, data augmentation via Machine Translation, and the continued pretraining of a state-of-the-art multilingual transformer, we evaluate the domain-adapted model on the Named Entity Recognition task. Experiments on this task show superior performance over the general-domain transformer in a multilingual domain-specific setting, including languages not seen during the domain adaptation.
Digital humanities projects increasingly rely on heterogeneous collections of multimodal data, including video testimonies, scanned documents, and photographs. Despite the growing availability of such archives, researchers face challenges in efficiently locating relevant content due to the diversity of formats and the lack of unified retrieval methods. In this work, we present a general framework for semantic search over collections of multiple modalities. The framework integrates specific parsers and transforms all inputs into textual representations leveraging services like automatic speech recognition (ASR), optical character recognition (OCR), and generative-AI-based image captioning. Text is subsequently segmented into overlapping chunks, indexed in a vector database, and enriched through an automatic question generation (AQ) pipeline to create ground-truth queries for evaluation. We evaluate the framework on a constructed dataset derived from Holocaust-related archives, comparing two retrieval strategies (pure vector search vs. hybrid semantic-lexical search) under two chunking scenarios. Results demonstrate that hybrid search consistently outperforms vector-only retrieval, achieving high recall across modalities, and that semantic search is feasible even with diverse and noisy input sources. This framework provides a robust foundation for exploring complex multimodal archives, facilitating access to content that would otherwise remain difficult to discover.

2018

2017

We summarize the involvement of our CEMI team in the ”NLI Shared Task 2017”, which deals with both textual and speech input data. We submitted the results achieved by using three different system architectures; each of them combines multiple supervised learning models trained on various feature sets. As expected, better results are achieved with the systems that use both the textual data and the spoken responses. Combining the input data of two different modalities led to a rather dramatic improvement in classification performance. Our best performing method is based on a set of feed-forward neural networks whose hidden-layer outputs are combined together using a softmax layer. We achieved a macro-averaged F1 score of 0.9257 on the evaluation (unseen) test set and our team placed first in the main task together with other three teams.

2008

Structural metadata extraction (MDE) research aims to develop techniques for automatic conversion of raw speech recognition output to forms that are more useful to humans and to downstream automatic processes. It may be achieved by inserting boundaries of syntactic/semantic units to the flow of speech, labeling non-content words like filled pauses and discourse markers for optional removal, and identifying sections of disfluent speech. This paper compares two Czech MDE speech corpora, one in the domain of broadcast news and the other in the domain of broadcast conversations. A variety of statistics about fillers, edit disfluencies, and syntactic/semantic units are presented. In addition, it is reported that disfluent portions of speech show differences in the distribution of parts of speech (POS) of their content in comparison with the general POS distribution. The two Czech corpora are not only compared with each other, but also with available numbers relating to English MDE corpora of broadcast news and telephone conversations.