Ismail Harrando


2021

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Apples to Apples: A Systematic Evaluation of Topic Models
Ismail Harrando | Pasquale Lisena | Raphael Troncy
Proceedings of the International Conference on Recent Advances in Natural Language Processing (RANLP 2021)

From statistical to neural models, a wide variety of topic modelling algorithms have been proposed in the literature. However, because of the diversity of datasets and metrics, there have not been many efforts to systematically compare their performance on the same benchmarks and under the same conditions. In this paper, we present a selection of 9 topic modelling techniques from the state of the art reflecting a diversity of approaches to the task, an overview of the different metrics used to compare their performance, and the challenges of conducting such a comparison. We empirically evaluate the performance of these models on different settings reflecting a variety of real-life conditions in terms of dataset size, number of topics, and distribution of topics, following identical preprocessing and evaluation processes. Using both metrics that rely on the intrinsic characteristics of the dataset (different coherence metrics), as well as external knowledge (word embeddings and ground-truth topic labels), our experiments reveal several shortcomings regarding the common practices in topic models evaluation.

2020

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TOMODAPI: A Topic Modeling API to Train, Use and Compare Topic Models
Pasquale Lisena | Ismail Harrando | Oussama Kandakji | Raphael Troncy
Proceedings of Second Workshop for NLP Open Source Software (NLP-OSS)

From LDA to neural models, different topic modeling approaches have been proposed in the literature. However, their suitability and performance is not easy to compare, particularly when the algorithms are being used in the wild on heterogeneous datasets. In this paper, we introduce ToModAPI (TOpic MOdeling API), a wrapper library to easily train, evaluate and infer using different topic modeling algorithms through a unified interface. The library is extensible and can be used in Python environments or through a Web API.