Automatic keyword extraction for a partial search engine index

Full-text search engines play a critical role in many enterprise applications, where the quantity and complexity of the information are overwhelming. Promptly finding documents that contain relevant information for pressing questions is a necessity for efficient operation. This is especially the case for financial and legal teams executing Mergers and Acquisitions deals. The goal of the thesis is to provide search services for such teams without storing the sensitive documents involved, minimising the risk of potential data leaks. A literature review of related methods and concepts is presented. As search engine technologies that use encrypted indices for commercial applications are still in their early stages, the solution proposed in the thesis is the use of partial indexing by keyword extraction. A cosine similarity-based evaluation was used to measure the performance difference between the keyword-based partial index and the complete index. The partial indices were constructed using unsupervised keyword extraction methods based on term frequency, document graphs, and topic modelling. The frequency-based methods were term frequency, TF-IDF, and YAKE!. The graph-based method was TextRank. The topic modelling-based methods were NMF, LDA, and LSI. The methods were evaluated by running 51 reference queries on the LEDGAR data set, which contains 60,540 contracts. The results show that using only five keywords per document from the TF-IDF or YAKE! methods, the best matching documents in the result lists have a cosine similarity of 0.7 on average. This value is reasonably high, particularly considering the small number of keywords. The topic modelling-based methods were found to perform poorly due to being too general. The term frequency and TextRank methods were mediocre

Alkalmazás melanóma esélyének becslésére fényképfelvétel alapján

This thesis presents a user-friendly desktop application for melanoma detection from skin lesion images. It is designed to offer a solution for both medical specialists and home users to receive a quick diagnosis and organise their results. The program is built on a lesion image classifier software - that is powered by a deep convolutional neural network ensemble - developed at the Dept. of Artificial Intelligence of Eötvös Loránd University