Knowledge Representation
Principal Investigator: Nisansa de Silva
The Knowledge Representation project investigates methods for structuring, aligning, and reasoning over knowledge extracted from language, with particular emphasis on low-resource settings, domain-specific semantics, and intelligent information access.
The Knowledge Representation project investigates methods for structuring, aligning, and reasoning over knowledge extracted from language, with particular emphasis on low-resource settings, domain-specific semantics, and intelligent information access. A central theme of the project is the development of richer semantic representations that move beyond simple similarity, including methods for modelling semantic oppositeness, domain-sensitive similarity, and representative vector construction for ontology classes. These approaches strengthen the ability of computational systems to capture nuanced conceptual relationships and support tasks such as inconsistency detection, disagreement analysis, and semantic error identification.
Another major focus is ontology-based information extraction, especially in specialised domains such as law and biomedicine. The project explores techniques for extracting facts, arguments, citations, and semantic relations from complex textual sources, using ontologies to guide knowledge structuring and logical reasoning. This is complemented by research on ontology population, concept expansion, concept map construction, and knowledge base generation from large document collections.
The project also addresses cross-lingual and low-resource knowledge representation, particularly for Sinhala, through word embedding alignment, bilingual lexical resources, WordNet development, and improved embedding architectures. By integrating symbolic knowledge, embeddings, logic rules, and domain ontologies, this body of work advances both the theoretical foundations and practical applications of knowledge representation for intelligent systems, multilingual processing, and domain-aware reasoning.
Objectives:
- Develop robust knowledge representation methods that capture complex semantic relationships, including similarity, oppositeness, and domain-specific meaning, to improve machine understanding of text.
- Design ontology-based frameworks for information extraction and reasoning that can structure knowledge from unstructured text and support applications in specialised domains such as law, biomedicine, and enterprise document analysis.
- Advance low-resource and cross-lingual knowledge representation by building lexical resources, aligned embeddings, and semantic tools for languages such as Sinhala.
- Integrate symbolic and neural approaches to knowledge modelling by combining ontologies, logic, embeddings, and rule-based methods to enable more accurate semantic analysis, retrieval, and decision support.
Keywords: Natural Language Processing | Machine Learning / Deep Learning | Ontologies | Big Data | Bioinformatics | Sinhala | Law | Word Embeddings | Semantic Similarity | Ontology Development | Low-resource Languages | Word Embedding Alignment | Word2vec | Information Extraction | Neural Networks | WordNet | Inflected Languages | Multilingual Embedding | Semantic Analysis | Multilingual | Bilingual Lexicon Induction | Text Classification | Semantic Oppositeness | Knowledge Graph | Data Annotation | Ontology Population | Lexicon | Information Retrieval |
Publications
Dissertations
Theses: MSc Minor Component Research
Kasun Wickramasinghe, "Bilingual Lexicon Induction for the Sinhala-English Language Pair", University of Moratuwa, 2024
Theses: BSc
Gathika Ratnayaka, Thejan Rupasinghe, Menuka Warushavithana, and Viraj Gamage, "Ontology-Based Information Extraction for Automatic Generation of Legal Arguments", University of Moratuwa, 2019
Vindula Jayawardana, Keet Sugathadasa, Dimuthu Lakmal, and Buddhi Rathnayake, "Ontology-Based Legal Information Extraction", University of Moratuwa, 2018
Nadeeshaan Gunasinghe, Dulanga Sashika, Anushka De Silva, and Thilina Premasiri, "Warana: Recruitment Helper for Enterprises", University of Moratuwa, 2015
Eranda Karannagoda, Thilina Herath, Jayaprabath Fernando, and Isura Karunarathne, "SigmaC: Document Analysis Based Automatic Concept Map Generation for Enterprises", University of Moratuwa, 2013
Journal Papers
Gathika Ratnayaka, Nisansa de Silva, Amal Shehan Perera, Gayan Kavirathne, Thirasara Ariyarathna, and Anjana Wijesinghe, "Context Sensitive Verb Similarity Dataset for Legal Information Extraction", Data, vol. 7, no. 7, 2022. doi: 10.3390/data7070087
Pengwei Wang, Lei Ji, Jun Yan, Dejing Dou, Nisansa de Silva, Yong Zhang, and Lianwen Jin, "Concept and Attention-Based CNN for Question Retrieval in Multi-View Learning", ACM Transactions on Intelligent Systems and Technology (TIST), vol. 9, no. 4, pp. 41, 2018. doi: 10.1145/3151957
Vindula Jayawardana, Dimuthu Lakmal, Nisansa de Silva, Amal Shehan Perera, Keet Sugathadasa, Buddhi Ayesha, and Madhavi Perera, "Word Vector Embeddings and Domain Specific Semantic based Semi-Supervised Ontology Instance Population", International Journal on Advances in ICT for Emerging Regions, vol. 10, no. 1, pp. 1, 2017. doi: 10.4038/icter.v11i1.7191
Fernando Gutierrez, Dejing Dou, Nisansa de Silva, and Stephen Fickas, "Online Reasoning for Semantic Error Detection in Text", Journal on Data Semantics, Jul. 2017. doi: 10.1007/s13740-017-0079-6
Jingshan Huang, Fernando Gutierrez, Harrison J Strachan, Dejing Dou, Weili Huang, Barry Smith, Judith A Blake, Karen Eilbeck, Darren A Natale, Yu Lin, Bin Wu, Nisansa de Silva, and others, "OmniSearch: a semantic search system based on the Ontology for MIcroRNA Target (OMIT) for microRNA-target gene interaction data", Journal of biomedical semantics, vol. 7, no. 1, pp. 25, 2016. doi: 10.1186/s13326-016-0064-2
Jingshan Huang, Karen Eilbeck, Barry Smith, Judith A Blake, Dejing Dou, Weili Huang, Darren A Natale, Alan Ruttenberg, Jun Huan, Michael T Zimmermann, Guoqian Jiang, Yu Lin, Bin Wu, Harrison J. Strachan, Nisansa de Silva, and others, "The development of non-coding RNA ontology", International journal of data mining and bioinformatics, vol. 15, no. 3, pp. 214--232, 2016. doi: 10.1504/IJDMB.2016.077072
Conference Papers
Kasun Wickramasinghe and Nisansa de Silva, "How Good is BLI as an Alignment Measure: A Study in Word Embedding Paradigm", in International Conference on Computational Collective Intelligence, 2025, pp. 383--397. doi: 10.1007/978-3-032-10202-7_26
Imalsha Puranegedara, Themira Chathumina, Nisal Ranathunga, Nisansa de Silva, Surangika Ranathunga, and Mokanarangan Thayaparan, "Utilizing Multilingual Encoders to Improve Large Language Models for Low-Resource Languages", in Moratuwa Engineering Research Conference (MERCon), 2025. doi: 10.1109/MERCon67903.2025.11216992
Kasun Wickramasinghe and Nisansa de Silva, "Sinhala-English Word Embedding Alignment: Introducing Datasets and Benchmark for a Low Resource Language", in Proceedings of the 37th Pacific Asia Conference on Language, Information and Computation, 2023, pp. 424--435.
Kasun Wickramasinghe and Nisansa de Silva, "Sinhala-English Parallel Word Dictionary Dataset", in 2023 IEEE 17th International Conference on Industrial and Information Systems (ICIIS), 2023, pp. 61--66. doi: 10.1109/ICIIS58898.2023.10253560
Gihan Weeraprameshwara, Vihanga Jayawickrama, Nisansa de Silva, and Yudhanjaya Wijeratne, "Sinhala Sentence Embedding: A Two-Tiered Structure for Low-Resource Languages", in Proceedings of the 36th Pacific Asia Conference on Language, Information and Computation, 2022, pp. 325--336. doi: 10.48550/ARXIV.2210.14472
Nisansa de Silva, "Selecting Optimum Seed Words for Wordle using Character Statistics", in 2022 Moratuwa Engineering Research Conference (MERCon), 2022, pp. 1--6. doi: 10.1109/MERCon55799.2022.9906176
Sahan Jayasinghe, Lakith Rambukkanage, Ashan Silva, Nisansa de Silva, and Amal Shehan Perera, "Critical Sentence Identification in Legal Cases Using Multi-Class Classification", in 2021 IEEE 16th International Conference on Industrial and Information Systems (ICIIS), 2021, pp. 146--151. doi: 10.1109/ICIIS53135.2021.9660657
Qiuhao Lu, Nisansa de Silva, Dejing Dou, Thien Huu Nguyen, Prithviraj Sen, Berthold Reinwald, and Yunyao Li, "Exploiting Node Content for Multiview Graph Convolutional Network and Adversarial Regularization", in Proceedings of the 28th International Conference on Computational Linguistics, 2020, pp. 545--555. doi: 10.18653/v1/2020.coling-main.47
Keet Sugathadasa, Buddhi Ayesha, Nisansa de Silva, Amal Shehan Perera, Vindula Jayawardana, Dimuthu Lakmal, and Madhavi Perera, "Synergistic Union of Word2Vec and Lexicon for Domain Specific Semantic Similarity", in 2017 IEEE International Conference on Industrial and Information Systems (ICIIS), 2017, pp. 1--6. doi: 10.1109/ICIINFS.2017.8300343
Vindula Jayawardana, Dimuthu Lakmal, Nisansa de Silva, Amal Shehan Perera, Keet Sugathadasa, Buddhi Ayesha, and Madhavi Perera, "Semi-Supervised Instance Population of an Ontology using Word Vector Embedding", in 2017 Seventeenth International Conference on Advances in ICT for Emerging Regions (ICTer), 2017, pp. 1--7. doi: 10.1109/icter.2017.8257822
Nisansa de Silva, Dejing Dou, and Jingshan Huang, "Discovering Inconsistencies in PubMed Abstracts Through Ontology-Based Information Extraction", in Proceedings of the 8th ACM International Conference on Bioinformatics, Computational Biology, and Health Informatics, New York, NY, USA: ACM, 2017, pp. 362--371. doi: 10.1145/3107411.3107452
Vindula Jayawardana, Dimuthu Lakmal, Nisansa de Silva, Amal Shehan Perera, Keet Sugathadasa, and Buddhi Ayesha, "Deriving a Representative Vector for Ontology Classes with Instance Word Vector Embeddings", in 2017 Seventh International Conference on Innovative Computing Technology (INTECH), 2017, pp. 79--84. doi: 10.1109/intech.2017.8102426
N. H. N. D. de Silva, "SAFS3 Algorithm: Frequency Statistic and Semantic Similarity Based Semantic Classification Use Case", in Advances in ICT for Emerging Regions (ICTer), 2015 Fifteenth International Conference on, August. 2015, pp. 77--83. doi: 10.1109/ICTER.2015.7377670
U. L. D. N. Gunasinghe, W. A. M. De Silva, N. H. N. D. de Silva, A. S. Perera, W. A. D. Sashika, and W. D. T. P. Premasiri, "Sentence Similarity Measuring by Vector Space Model", in Advances in ICT for Emerging Regions (ICTer), 2014 International Conference on, December. 2014, pp. 185--189. doi: 10.1109/ICTER.2014.7083899
Indeewari Wijesiri, Malaka Gallage, Buddhika Gunathilaka, Madhuranga Lakjeewa, Daya Wimalasuriya, Gihan Dias, Rohini Paranavithana, and Nisansa de Silva, "Building a WordNet for Sinhala", in Proceedings of the Seventh Global WordNet Conference, January. 2014, pp. 100--108.
N. H. N. D. de Silva, A. S. Perera, and M. K. D. T. Maldeniya, "Semi-Supervised Algorithm for Concept Ontology Based Word Set Expansion", in Advances in ICT for Emerging Regions (ICTer), 2013 International Conference on, December. 2013, pp. 125--131. doi: 10.1109/ICTer.2013.6761166
E. L. Karannagoda, H. M. T. C. Herath, K. N. J. Fernando, M. W. I. D. Karunarathne, N. H. N. D. de Silva, and A. S. Perera, "Document Analysis Based Automatic Concept Map Generation for Enterprises", in Advances in ICT for Emerging Regions (ICTer), 2013 International Conference on, December. 2013, pp. 154--159. doi: 10.1109/ICTer.2013.6761171
N. H. N. D. de Silva, C. S. N. J. Fernando, M. K. D. T. Maldeniya, D. N. C. Wijeratne, A. S. Perera, and B Goertzel, "SeMap-Mapping Dependency Relationships into Semantic Frame Relationships", in Proceedings of the Engineering Research Unit Symposium, December. 2011.
Preprints
Pengwei Wang, Dejing Dou, Fangzhao Wu, Nisansa de Silva, and Lianwen Jin, "Logic Rules Powered Knowledge Graph Embedding", arXiv preprint arXiv:1903.03772, 2019. doi: 10.48550/arXiv.1903.03772
Nisansa de Silva, "Sinhala Text Classification: Observations from the Perspective of a Resource Poor Language", , 2015
Team
External Collaborators: | Shehan Perera | Dejing Dou | Madhavi Perera | Fernando Gutierrez | Stephen Fickas | Jingshan Huang | Surangika Ranathunga | Mokanarangan Thayaparan | Yudhanjaya Wijeratne | Thien Huu Nguyen | Prithviraj Sen | Berthold Reinwald | Yunyao Li | Chinthana Wimalasuriya | Gihan Dias | Nirmal Fernando | Danaja Maldeniya | Chamilka Wijeratne | Ben Goertzel |
