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The goal of our research is to compare novel semantic techniques for identifying implicit links between utterances in multi-participant CSCL chat conversations. Cohesion, reflected by the strength of the semantic relations behind the automatically identified links, is assessed using WordNet-based semantic distances, as well as unsupervised semantic models, i.e. Latent Semantic Analysis (LSA) and Latent Dirichlet Allocation (LDA). The analysis is built on top of the ReaderBench framework and multiple identification heuristics were compared, including: semantic cohesion metrics, normalized cohesion measures and Mihalcea's formula. A corpus of 55 conversations in which participants used explicit links between utterances where they considered necessary for clarity was used for validation. Our study represents an in-depth analysis of multiple methods used to identify implicit links and reveals the accuracy of each technique in terms of capturing the explicit references made by users. Statistical similarity measures ensured the best overall identification accuracy when using Mihalcea's formula, while WordNet-based techniques provided best results for un-normalized similarity scores applied on a window of 5 utterances and a time frame of 1 minute. ; This study is part of the RAGE project. The RAGE project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 644187. This publication reflects only the author's view. The European Commission is not responsible for any use that may be made of the information it contains.

This paper presents a research on using Word2Vec for determining implicit links in multi-participant Computer-Supported Collaborative Learning chat conversations. Word2Vec is a powerful and one of the newest Natural Language Processing semantic models used for computing text cohesion and similarity between documents. This research considers cohesion scores in terms of the strength of the semantic relations established between two utterances; the higher the score, the stronger the similarity between two utterances. An implicit link is established based on cohesion to the most similar previous utterance, within an imposed window. Three similarity formulas were used to compute the cohesion score: an unnormalized score, a normalized score with distance and Mihalcea's formula. Our corpus of conversations incorporated explicit references provided by authors, which were used for validation. A window of 5 utterances and a 1- minute time frame provided the highest detection rate both for exact matching and matching of a block of continuous utterances belonging to the same speaker. Moreover, the unnormalized score correctly identified the largest number of implicit links. ; This study is part of the RAGE project. The RAGE project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 644187. This publication reflects only the author's view. The European Commission is not responsible for any use that may be made of the information it contains.