• Identifying Essential Job Skills in the Job Market
  A.-F. Ntogramatzis, A. Ntoulas
  Int. Conf. on Emerging Internet, Data & Web Technologies (EIDWT 2026), Springer, pp. 34–46
• Wellness Recommendations Using Genetic Algorithms
  A. Ntountoulakis, A. Ntoulas
  Int. Conf. on Emerging Internet, Data & Web Technologies (EIDWT 2026), Springer, pp. 173–186

• Rapid Detection of Local Communities in Graph Streams
  P. Liakos, K. Papakonstantinopoulou, A. Ntoulas, A. Delis
  IEEE Transactions on Knowledge and Data Engineering (TKDE) 34(5), pp. 2375–2386, 2022 PDF
• Uncovering Local Hierarchical Overlapping Communities at Scale
  P. Liakos, A. Ntoulas, A. Delis
  IEEE Transactions on Big Data 8(2), pp. 432–445, 2022 PDF

• DeepReduce: A Sparse-tensor Communication Framework for Federated Deep Learning
  H. Xu, K. Kostopoulou, A. Dutta, X. Li, A. Ntoulas, P. Kalnis
  Advances in Neural Information Processing Systems (NeurIPS 2021), pp. 21150–21163 Link

• Advances in Knowledge Discovery and Data Mining: 24th Pacific-Asia Conference, PAKDD 2020, Proceedings
  H. W. Lauw, R. C.-W. Wong, A. Ntoulas, E.-P. Lim, S.-K. Ng, S. J. Pan (eds.)
  Lecture Notes in Computer Science, Springer, 2020

• DiCeS: Detecting Communities in Network Streams Over the Cloud
  P. Liakos, K. Papakonstantinopoulou, A. Ntoulas, A. Delis
  IEEE International Conference on Cloud Computing (CLOUD 2019), Milan, Italy PDF

• CoEuS: Community Detection via Seed-set Expansion on Graph Streams
  P. Liakos, A. Ntoulas, A. Delis
  IEEE International Conference on Big Data (BigData 2017), Boston, MA PDF
• Rhea: Adaptively Sampling Authoritative Content from Social Activity Streams
  P. Liakos, A. Ntoulas, A. Delis
  IEEE International Conference on Big Data (BigData 2017), Boston, MA PDF

• Scalable Link Community Detection: A Local Dispersion-aware Approach
  P. Liakos, A. Ntoulas, A. Delis
  IEEE International Conference on Big Data (BigData 2016), Washington, DC PDF
• Focused Crawling for the Hidden Web
  P. Liakos, A. Ntoulas, A. Labrinidis, A. Delis
  World Wide Web Journal 19(4), pp. 605–631, 2016 PDF

• Efficient Online Novelty Detection in News Streams
  M. Karkali, F. Rousseau, A. Ntoulas, M. Vazirgiannis
  Int. Conf. on Web Information Systems Engineering (WISE 2013), Nanjing, China PDF
• SocWeb: Efficient Monitoring of Social Network Activities
  F. Psallidas, A. Ntoulas, A. Delis
  Int. Conf. on Web Information Systems Engineering (WISE 2013), Nanjing, China PDF

• PocketWeb: Instant Web Browsing for Mobile Devices
  D. Lymberopoulos, O. Riva, K. Strauss, A. Mittal, A. Ntoulas
  Int. Conf. on Architectural Support for Programming Languages and Operating Systems (ASPLOS 2012), London, UK PDF
• Topic-Sensitive Hidden-Web Crawling
  P. Liakos, A. Ntoulas
  Int. Conf. on Web Information Systems Engineering (WISE 2012), Paphos, Cyprus PDF
• Organizing User Search Histories
  H. Hwang, H. W. Lauw, L. Getoor, A. Ntoulas
  IEEE Transactions on Knowledge and Data Engineering (TKDE) 24(5), pp. 912–925, 2012 PDF

• Selecting a Comprehensive Set of Reviews
  P. Tsaparas, A. Ntoulas, E. Terzi
  ACM SIGKDD Conference on Knowledge Discovery and Data Mining (KDD 2011), San Diego, CA PDF
• Indexing Strategies for Graceful Degradation of Search Quality
  S. Ding, S. Gollapudi, S. Ieong, K. Kenthapadi, A. Ntoulas
  ACM SIGIR Conference on Research and Development in Information Retrieval (SIGIR 2011), Beijing, China PDF
• Efficient Query Rewrite for Structured Web Queries
  S. Gollapudi, S. Ieong, A. Ntoulas, S. Paparizos
  ACM Conference on Information and Knowledge Management (CIKM 2011), Glasgow, UK PDF
• Rank-Aware Crawling of Hidden-Web Sites
  G. Valkanas, A. Ntoulas, D. Gunopulos
  International Workshop on the Web and Databases (WebDB 2011, with SIGMOD), Athens, Greece PDF

• Exploiting Social Context for Review Quality Prediction
  Y. Lu, P. Tsaparas, A. Ntoulas, L. Polanyi
  International World Wide Web Conference (WWW 2010), Raleigh, NC PDF
• Homophily in the Digital World: A LiveJournal Case Study
  H. W. Lauw, J. C. Shafer, R. Agrawal, A. Ntoulas
  IEEE Internet Computing 14(2), pp. 15–23, 2010 PDF
• Estimating the Quality of Postings in the Real-time Web
  H. W. Lauw, A. Ntoulas, K. Kenthapadi
  WSDM Workshop on Search in Social Media (SSM 2010), New York, NY PDF

• Releasing Search Queries and Clicks Privately Best Paper Award runner-up
  A. Korolova, K. Kenthapadi, N. Mishra, A. Ntoulas
  International World Wide Web Conference (WWW 2009), Madrid, Spain PDF
• Answering Web Queries Using Structured Data Sources
  S. Paparizos, A. Ntoulas, J. C. Shafer, R. Agrawal
  ACM SIGMOD International Conference on Management of Data (SIGMOD 2009), Providence, RI PDF
• Search Personalization through Query and Page Topical Analysis
  S. Stamou, A. Ntoulas
  User Modeling and User-Adapted Interaction 19(1), pp. 5–33, 2009 PDF

• Web Search
  A. Ntoulas, M. Vazirgiannis
  Special volume of the Hellenic Artificial Intelligence Society (EETN), 2008 PDF

• Pruning Policies for Two-Tiered Inverted Index with Correctness Guarantee
  A. Ntoulas, J. Cho
  ACM SIGIR Conference on Research and Development in Information Retrieval (SIGIR 2007), Amsterdam, Netherlands PDF
• Answering Bounded Continuous Search Queries in the World Wide Web
  D. Kukulenz, A. Ntoulas
  International World Wide Web Conference (WWW 2007), Banff, Canada PDF
• Modeling and Managing Content Changes in Text Databases
  P. G. Ipeirotis, A. Ntoulas, J. Cho, L. Gravano
  ACM Transactions on Database Systems (TODS) 32(3), 2007 PDF
• The Infocious Web Search Engine: Improving Web Searching through Linguistic Analysis
  A. Ntoulas, G. Chao, J. Cho
  Journal of Digital Information Management 5(5), pp. 277–291, 2007 PDF
• Microsoft Silicon Valley Web Spam Challenge Entry
  S. Chien, D. Fetterly, M. Manasse, M. Najork, A. Ntoulas
  Int. Workshop on Adversarial Information Retrieval on the Web (AIRWeb 2007), Banff, Canada
• TODE: An Ontology-Based Model for the Dynamic Population of Web Directories
  S. Stamou, A. Ntoulas, D. Christodoulakis
  In Data Mining with Ontologies: Implementations, Findings and Frameworks, Idea Group, 2007 PDF

• Crawling and Searching the Hidden Web
  A. Ntoulas
  Ph.D. Dissertation, University of California, Los Angeles, 2006 PDF
• Detecting Spam Web Pages through Content Analysis
  A. Ntoulas, M. Najork, M. Manasse, D. Fetterly
  International World Wide Web Conference (WWW 2006), Edinburgh, UK PDF
• Classifying Web Data in Directory Structures
  S. Stamou, A. Ntoulas, V. Krikos, P. Kokosis, D. Christodoulakis
  Asia-Pacific Web Conference (APWeb 2006), Harbin, China, LNCS 3841, pp. 238–249 PDF

• Modeling and Managing Content Changes in Text Databases Best Paper Award
  P. G. Ipeirotis, A. Ntoulas, J. Cho, L. Gravano
  IEEE International Conference on Data Engineering (ICDE 2005), Tokyo, Japan PDF
• Downloading Textual Hidden Web Content through Keyword Queries
  A. Ntoulas, P. Zerfos, J. Cho
  ACM/IEEE Joint Conference on Digital Libraries (JCDL 2005), Denver, CO PDF
• The Infocious Web Search Engine: Improving Web Searching through Linguistic Analysis
  A. Ntoulas, G. Chao, J. Cho
  International World Wide Web Conference (WWW 2005), Chiba, Japan PDF
• A Study on the Evolution of the Web
  A. Ntoulas, J. Cho, H. K. Cho, H. Cho, Y. J. Cho
  US–Korea Conference on Science, Technology & Entrepreneurship (UKC 2005), Irvine, CA PDF
• Web Directory Construction Using Lexical Chains
  S. Stamou, V. Krikos, P. Kokosis, A. Ntoulas, D. Christodoulakis
  Int. Conf. on Applications of Natural Language to Information Systems (NLDB 2005), Alicante, Spain PDF
• DirectoryRank: Ordering Pages in Web Directories
  V. Krikos, S. Stamou, P. Kokosis, A. Ntoulas, D. Christodoulakis
  ACM Int. Workshop on Web Information and Data Management (WIDM 2005), Bremen, Germany PDF

• What's New on the Web? The Evolution of the Web from a Search Engine Perspective
  A. Ntoulas, J. Cho, C. Olston
  International World Wide Web Conference (WWW 2004), New York, NY PDF

• Effective Change Detection Using Sampling
  J. Cho, A. Ntoulas
  International Conference on Very Large Data Bases (VLDB 2002), Hong Kong, China PDF
• Expanding EuroWordNet with Domain-Specific Terminology Using Common Lexical Resources: Vocabulary Completeness and Coverage Issues
  S. Stamou, A. Ntoulas, M. Kyriakopoulou, D. Christodoulakis
  Global WordNet Conference (GWC 2002), Mysore, India PDF
• EUROTERM: Extending the EuroWordNet with Domain-Specific Terminology Using an Expand Model Approach
  S. Stamou, A. Ntoulas, J. Hoppenbrouwers, M. Saiz-Noeda, D. Christodoulakis
  Global WordNet Conference (GWC 2002), Mysore, India PDF

• Understanding Search Engines: Requirements for Explaining Search Results
  A. Ntoulas, S. Stamou, M. Tzagarakis, D. Christodoulakis
  Panhellenic Conference on Human–Computer Interaction (PCHCI 2001), Patras, Greece PDF
• Viewing Web Search Engines as Corpus Query Systems
  A. Ntoulas, S. Stamou, M. Tzagarakis, I. Tsakou, D. Christodoulakis
  Conference on Computational Lexicography and Corpus Research (COMPLEX 2001), Birmingham, UK PDF
• Athena: A User-Friendly Computer Tool for the Construction and Management of Language Exercises
  A. Ntoulas, N. Arvanitakis, A. Iordanidou
  National Conference on School Knowledge and Teaching in Primary Education, Ioannina, Greece, 2001 PDF
• Using a WWW Search Engine to Evaluate Normalization Performance for a Highly Inflectional Language
  A. Ntoulas, S. Stamou, M. Tzagarakis
  ACL/EACL Student Research Workshop, Toulouse, France, 2001 PDF

• Use of a Morphosyntactic Lexicon for the Implementation of the Greek WordNet
  A. Ntoulas, S. Stamou, I. Tsakou, C. Tsalidis, M. Tzagarakis, A. Vagelatos
  International Conference on Natural Language Processing (NLP 2000), Patras, Greece PDF
• A Modular Architecture for the Storage and Management of Heterogeneous Lexical Information
  D. Assimakopoulos, I. Koutsoubos, M. Miatidis, I. Tsakou, A. Ntoulas, S. Stamou, D. Christodoulakis
  Computational Lexicography Workshop (COMLEX 2000), Patras, Greece PDF

Patents

• Dynamic game difficulty modification via swipe input parameter change
  US Patent 11,498,006
• Automated game modification based on playing style
  US Patent 11,148,057
• Optimizing content item delivery for installations of a mobile application
  US Patent 11,151,603
• Content item similarity detection
  US Patent 11,102,534
• Adjusting object adaptive modification or game level difficulty and physical gestures through level definition files
  US Patent 11,083,969
• Server-to-server integration of tracking events
  US Patent 10,764,382
• Automated tuning of computer-implemented games
  US Patent 10,729,979
• Adjusting object adaptive modification or game level difficulty and physical gestures through level definition files
  US Patent 10,561,944
• Automated game modification based on playing style
  US Patent 10,556,182
• Dynamic virtual environment customization based on user behavior clustering
  US Patent 10,315,116
• Automated tuning of computer-implemented games
  US Patent 10,105,603
• Relaxation for structured queries
  US Patent 9,158,813
• Assessing the quality of user reviews
  US Patent 8,990,124
• Answering web queries using structured data sources
  US Patent 8,832,133
• Synopsis of a search log that respects user privacy
  US Patent 8,601,024
• Indexing for limited search server availability
  US Patent 8,458,130
• Grammar compression
  US Patent 8,447,736
• Grammar compression
  US Patent 8,027,957
• Using content analysis to detect spam web pages
  US Patent 7,962,510
• Method and apparatus for retrieving and indexing hidden web pages
  US Patent 7,685,112