Journal Articles

  1. S. Aftab and H. Ramampiaro, (2024), "Improving Top-N Recommendations using Batch Approximation for Weighted Pair-Wise Loss". In Machine Learning with Applications, 15. Elsevier. ISSN: 2666-8270. Impact Factor: 8.5 (accepted). [PDF] [BIB] [DOI].
  2. S. Aftab, H. Ramampiaro, Helge Langseth and Massimiliano Ruocco, (2023), "Deep Contextual Grid Triplet Network for Context-Aware Recommendation". In IEEE Access. IEEE. ISSN: 2169-3536. Impact Factor: 3.9. [PDF] [BIB] [DOI].
  3. S. Aftab and H. Ramampiaro, (2022), "Evaluating Top-N Recommendations Using Ranked Error Approach: An Empirical Analysis". In IEEE Access. IEEE. ISSN: 2169-3536. Impact Factor: 3.9. [PDF] [BIB] [DOI].
  4. D. Groos, L. Adde, S. Aubert, L. Boswell, R. A. de Regnier, T. Fjørtoft, D. Gaebler-Spira, A. Haukeland, M. Loennecken, M. Msall, U. I. Möinichen, A. Pascal, C. Peyton, H. Ramampiaro, M. D. Schreiber, I. E. Silberg, N. T. Songstad, N. Thomas, C. Van den Broeck, G. K. Øberg, E. A. F. Ihlen, and R. Støen, (2022), "Development and Validation of a Deep Learning Method to Predict Cerebral Palsy From Spontaneous Movements in Infants at High Risk". In JAMA Network Open, 2022, 5(7). JAMA. ISSN: 2574-3805. Impact Factor: 13.37. [PDF] [BIB] [DOI].
  5. S. Tiwari, G. Bell, H. Langseth and H. Ramampiaro, (2022), "Machine Learning in Financial Market Surveillance: A Survey". In IEEE Access. IEEE. ISSN: 2169-3536. Impact Factor: 3.9. [PDF] [BIB] [DOI].
  6. D. Groos, L. Adde, R. Støen, H. Ramampiaro and E. Ihlen, (2022), "Towards human-level performance on automatic pose estimation of infant spontaneous movements". In Computerized Medical Imaging and Graphics 95. Elsevier. ISSN: 0895-6111. Impact Factor: 4.790 (accepted). [PDF] [BIB] [DOI].
  7. Q. H. Duong, H. Ramampiaro, and K. Nørvåg, (2021), "Density Guarantee on Finding Multiple Subgraphs and Subtensors". In ACM Transactions on Knowledge Discovery from Data (TKDD), 15(5), article no. 76. ACM Press. ISSN: 1556-4681. Impact Factor: 3.089. [PDF] [BIB] [DOI].
  8. Y. Djenouri, J. C. Lin, K. Nørvåg, H. Ramampiaro, and Philip S. Yu, (2021), "Exploring Decomposition for Solving Pattern Mining Problems". In ACM Transactions on Management Information Systems (TMIS), 12(2), article no. 15. ACM. ISSN 2158-656X. Impact Factor: 1.5. [PDF] [BIB] [DOI].
  9. D. Groos, H. Ramampiaro, E. Ihlen, (2020), "EfficientPose: Scalable single-person pose estimation". In Applied Intelligence Journal (APIN), 51, pp. 2518-2533. Springer. ISSN: 0924-669X. Impact Factor: 3.325 (2019). [PDF] [BIB] [DOI].
  10. A. Belhadia, Y. Djenouri, K. Nørvåg, H. Ramampiaro, F. Masseglia and J. Chun-WeiLin, (2020), "Space-time series clustering: Algorithms, taxonomy, and case study on urban smart cities". In Engineering Applications of Artificial Intelligence, 95. Elsevier. Impact Factor: 4.201. [PDF] [BIB] [DOI].
  11. D. Groos, K. Aurlien, H. Ramampiaro, E. A. Ihlen, RA deRegnier, C. Peyton, I. E. Silberg, N. T. Songstad, N. Thomas, L. Adde, (2019), "Deep Learning-based infant motion tracking facilitating early detection of cerebral palsy". In Developmental Medicine & Child Neurology Journal, 61(S2). Wiley. ISSN 0012-1622. Impact Factor: 3.532.
  12. Ö. Özdikis, H. Ramampiaro and K. Nørvåg, (2019), "Locality-Adapted Kernel Densities of Term Co-occurrences for Location Prediction of Tweets". In Information Processing & Management Journal (IPM), 56(4), pp. 1280-1299. Elsevier. ISSN: 0306-4573. Impact Factor: 3.892 (2018). [PDF] [BIB] [DOI].
  13. T. L. Dam, H. Ramampiaro, K. Nørvåg, and Q. H. Duong, (2019), "Towards Efficiently Mining Closed High Utility Itemsets from Incremental Databases". In Knowledge-Based Systems, 165, pp. 13-29. Elsevier. ISSN: 0950-7051. Impact Factor: 5.101. [PDF] [BIB] [DOI].
  14. Q. H. Duong, H. Ramampiaro, and K. Nørvåg, (2018), "Applying Temporal Dependence to Detect Changes in Streaming Data". In Applied Intelligence Journal (APIN), 48(12), pp. 4805-4823. Springer. ISSN: 0924-669X. Impact Factor: 1.983. [PDF] [BIB] [DOI].
  15. GK Pitsilis, H. Ramampiaro, H Langseth, (2018), "Effective hate-speech detection in Twitter data using recurrent neural networks". In Applied Intelligence Journal (APIN), 48(12), pp. 4730-4742. Springer. ISSN: 0924-669X. Impact Factor: 1.983. [PDF] [BIB] [DOI].
  16. B Agarwal, H. Ramampiaro, H Langseth, M Ruocco, (2018), "A Deep Network Model for Paraphrase Detection in Short Text Messages". In Information Processing & Management Journal (IPM), 54(6), pp. 922-937. Elsevier. ISSN: 0306-4573. Impact Factor: 3.892 (2018). [PDF] [BIB] [DOI].
  17. Ø. Repp and H. Ramampiaro, (2018), "Extracting News Events from Microblogs". In Journal of Statistics and Management Systems, 21(4), pp. 695-723. Taylor & Francis. [PDF] [BIB] [DOI].
  18. Q. H. Duong, H. Ramampiaro, K. Nørvåg, P. Fournier-Viger and T. L. Dam, (2018), "High Utility Drift Detection in Quantitative Data Streams". In Knowledge-Based Systems, 157, pp. 34-51. Elsevier. ISSN: 0950-7051. Impact Factor: 5.101. [PDF] [BIB] [DOI].
  19. Q. H. Duong, P. Fournier-Viger, H. Ramampiaro, K. Nørvåg and T. L. Dam, (2018), "Efficient High Utility Itemset Mining using Buffered Utility-Lists". In Applied Intelligence Journal (APIN), 48(7), pp. 1859-1877. Springer. ISSN: 0924-669X. Impact Factor: 1.983 (2017). [PDF] [BIB] [DOI].
  20. M. Ruocco and H. Ramampiaro, (2015), "Geo-Temporal Distribution of Tag Terms for Event-Related Image Retrieval". In Information Processing & Management Journal (IPM), 51(1), pp. 92-110. Elsevier. ISSN: 0306-4573. Impact Factor: 2.391 (2016). [PDF] [BIB] [DOI].
  21. M. Ruocco and H. Ramampiaro, (2014), "A Scalable Algorithm for Extraction and Clustering of Event-Related Pictures". In Multimedia Tools and Applications Journal (MTAP), 70(1), pp. 55-88. Springer. ISSN: 1380-7501. Impact Factor: 1.530. [PDF] [BIB] [DOI].
  22. M. Ruocco and H. Ramampiaro, (2013), "Event-Related Image Retrieval: Exploring Geographical and Temporal Distribution of User Tags". In International Journal of Multimedia Information Retrieval (JMIR), 2(4), pp 273-288. Springer. ISSN: 2192-6611. [PDF] [BIB] [DOI].
  23. H. Ramampiaro and C. Li, (2011), "Supporting BioMedical Information Retrieval: The BioTracer Approach". In Transactions on Large-Scale Data- and Knowledge-Centered Systems (TLDKS) 4, Vol. 6990, pp. 73-94, 2011. Springer. [PDF] [BIB] [DOI].
  24. V. Beisvag, F. Jünge, H. Bergum, L. Jølsum, S. Lydersen, C.C. Günther, H. Ramampiaro, M. Langaas, A.K. Sandvik, and A. Lægreid, (2006), "GeneTools: application for functional annotation and statistical hypothesis testing". In BMC Bioinformatics, 7(1). BioMed Central. Impact Factor: 2.213. [PDF] [BIB] [DOI].
  25. H. Ramampiaro and M. Nygård, (2004), "CAGISTrans: Providing adaptable transactional support for cooperative work - An Extended Treatment". In Information Technology & Management (ITM) Journal, 5, 23-64. Kluwer Academic Publisher / Springer. Impact Factor: 1.635. [PDF] [BIB] [DOI].
  26. Conference Papers (refereed)

  27. David Baumgartner, Helge Langseth, Heri Ramampiaro, and Kenth Engø-Monsen, (2023), "mTADS: Multivariate Time Series Anomaly Detection Benchmark Suites". In Proceedings of 2023 IEEE International Conference on Big Data (BigData 2023) . IEEE. In Press [BIB] .
  28. T. Salem, H Langseth and H. Ramampiaro, (2020), "Prediction Intervals: Split Normal Mixture from Quality-Driven Deep Ensembles". In Proceedings of the 36th Conference on Uncertainty in Artificial Intelligence (UAI), PMLR volume 124, pp. 1179-1187, 2020. AUAI. [PDF] [BIB] .
  29. Q. H. Duong, H. Ramampiaro, and K. Nørvåg, (2020), "Multiple Dense Subtensor Estimation with High Density Guarantee". In Proceedings of 36th IEEE International Conference on Data Engineering (ICDE 2020), pp. 637-648. IEEE. [PDF] [BIB] [DOI].
  30. Q. H. Duong, H. Ramampiaro, and K. Nørvåg, (2019), "Sketching Streaming Histogram Elements using Multiple Weighted Factors". In Proceedings of The 28th ACM International Conference on Information and Knowledge Management (CIKM 2019), pp. 19-28. ACM Press. [PDF] [BIB] [DOI].
  31. Y. Djenouri, J. C. Lin, K. Nørvåg, and H. Ramampiaro, (2019), "Highly Efficient Pattern Mining Based on Transaction Decomposition". In Proceedings of 35th IEEE International Conference on Data Engineering (ICDE 2019), pp. 1646-1649. IEEE. [PDF] [BIB] [DOI].
  32. T. Salem, K. Kathuria, H. Ramampiaro and H Langseth, (2019), "Forecasting Intra-Hour Imbalances in Electric Power Systems". In Proceedings of the AAAI Conference on Artificial Intelligence, 33(01) - IAAI Technical Papers: Emerging Papers, pp. 9595-9600. AAAI Press. ISSN: 2159-5399. [PDF] [BIB] [DOI].
  33. GK Pitsilis, H. Ramampiaro, H Langseth, (2018), "Securing Tag-Based Recommender Systems Against Profile Injection Attacks: A comparative Study". In Proceedings of the Late-Breaking Results track part of the 12th ACM Conference on Recommender Systems (RecSys 2018). ACM. [PDF] [BIB] .
  34. Ö. Özdikis, H. Ramampiaro and K. Nørvåg, (2018), "Locality-adapted Kernel Densities for Tweet Localization". In Proc. of the 41st International ACM SIGIR Conference on Research and Development in Information Retrieval (SIGIR 2018), pp. 1149-1152. ACM Press. [PDF] [BIB] [DOI].
  35. W. Alkowaileet, S. Alsubaiee, M. J. Carey, C. Li, H. Ramampiaro, P. Sinthong, and X. Wang, (2018), "End-to-End Machine Learning with Apache AsterixDB". In 2nd ACM SIGMOD Workshop on Data Management for End-to-End Machine Learning (DEEM 2018). ACM Press. [PDF] [BIB] [DOI].
  36. W. Alkowaileet, S. Alsubaiee, M. J. Carey, C. Li, H. Ramampiaro, P. Sinthong, and X. Wang, (2018), "Enhancing Big Data with Semantics: The AsterixDB Approach (Poster)". In 12th IEEE International Conference on Semantic Computing (ICSC 2018). pp. 314-315. IEEE. [PDF] [BIB] .
  37. Ö. Özdikis, H. Ramampiaro and K. Nørvåg, (2018), "Spatial Statistics of Term Co-occurrences for Location Prediction of Tweets". In Proc. of the European Conference on Information Retrieval (ECIR 2018), pp. 494-506. Springer. [PDF] [BIB] .
  38. E. S. Silva, H. Langseth and H. Ramampiaro, (2017), "Content-Based Social Recommendation with Poisson Matrix Factorization". In Proc. of the joint European Conference on Machine Learning and Principles and Practice of Knowledge Discovery in Databases (ECML PKDD 2017). Springer. [PDF] [BIB] [DOI].
  39. Hai Thanh Nguyen, Martin Havig, Herman Schistad, Thomas Almenningen, Anders Kofod-Petersen, Helge Langseth and Heri Ramampiaro, (2014), "Learning to Rank for Personalised Fashion Recommender Systems via Implicit Feedback". 2nd International Conference on Mining Intelligence and Knowledge Exploration (MIKE 2014). pp. 51-61. Springer [BIB] [DOI].
  40. K. Balog and H. Ramampiaro, (2013), "Cumulative Citation Recommendation: Classification vs. Ranking". In Proc. of 36th international ACM SIGIR conference on Research and development in Information Retrieval (SIGIR 2013). ACM Press. [PDF] [BIB] [DOI].
  41. K. Balog, H. Ramampiaro, and K. Nørvåg, (2013), "KBAAA: A Web-based Toolkit for the Assessment and Analysis of Knowledge Base Acceleration Systems (Demo)". In Proc. of Open research Areas in Information Retrieval Conference (OAIR 2013). ACM Press [BIB] .
  42. K. Balog, H. Ramampiaro, N. Takhirov, and K. Nørvåg., (2013), "Multi-step Classification Approaches to Cumulative Citation Recommendation". In Proc. of Open research Areas in Information Retrieval Conference (OAIR 2013). ACM Press. [PDF] [BIB] .
  43. M. Ruocco and H. Ramampiaro, (2013), "Exploring Temporal Proximity and Spatial Distribution of Terms in Web-based Search of Event-Related Images". In Proc. of the 24th ACM Conference on Hypertext and Social Media (HT 2013). ACM Press. [PDF] [BIB] .
  44. H. Ren, T. B. Moeslund, S. Tang, and H. Ramampiaro, (2013), "Small Vocabulary with Saliency Matching for Video Copy Detection". In Proceedings of the 8th International Conference on Computer Vision Theory and Applications (VISAPP 2013) - Vol. 1, pp. 768-773. SciTePress. ISBN: 9789898565471. [PDF] [BIB] [DOI].
  45. M. Ruocco and H. Ramampiaro, (2012), "Exploratory Analysis on Heterogeneous Tag-Point Patterns for Ranking and Extracting Hot-Spot Related Tags". Proceedings of the 5th ACM SIGSPATIAL International Workshop on Location-Based Social Networks (LBSN 2012). ACM Press [BIB] [DOI].
  46. M. Ren, H. Ramampiaro, Yongdong Zhang and Shouxun Lin, (2012), "An Incremental Clustering Based Codebook Construction in Video Copy Detection". In Proc. of the 2012 IEEE Southwest Symposium on Image Analysis and Interpretation (SSIAI 2012). IEEE Computer Society [BIB] [DOI].
  47. M. Ruocco and H. Ramampiaro, (2011), "NTNU@MediaEval 2011 Social Event Detection Task (SED)". Working Notes Proceedings of the MediaEval 2011 Workshop (MediaEval 2011). WISU Verlag Aachen. ISSN: 1613-0073. [PDF] [BIB] .
  48. H. Ramampiaro and A. Grande, (2011), "DNA Sequence Search Using Content-Based Image Search Approach". In Proc. of 5th International Conference on Practical Applications of Computational Biology & Bioinformatics, 6-8 April 2011, Salamanca, Spain. Springer Verlag. Advances in Intelligent and Soft Computing, 2011, Volume 93/2011, 191-199.
  49. H. Ramampiaro, (2010), "BioMedical Information Retrieval: The BioTracer Approach". In Proc. of 1st International Conference on Information Technology in Bio- and Medical Informatics (ITBAM 2010), Bilbao, Spain, September 1-2, 2010.. LNCS Springer Verlag. Lecture Notes in Computer Science 6266 Springer 2010, ISBN 978-3-642-15019-7.
  50. M. Ruocco and H. Ramampiaro, (2010), "Event Clusters Detection on Flickr Images using a Suffix-Tree Structure". In Proc. of The IEEE International Symposium on Multimedia (ISM2010), Taichung, Taiwan, Dec. 13-15, 2010. IEEE Computer Society.
  51. H. Ramampiaro, D. Cruzes, R. Conradi, and M. Mendonça, (2010), "Supporting Evidence-Based Software Engineering with Collaborative Information Retrieval ". In Proc of the 6th International Conference on Collaborative Computing: Networking, Applications and Worksharing. IEEE.
  52. Y. H. Chen, H. Ramampiaro, A. Lægreid and R. Sætre, (2007), "ProtIR prototype: abstract relevance for Protein-Protein Interaction in BioCreAtIvE2 Challenge, PPI-IAS subtask". Proceedings of the Second BioCreative Challenge Evaluation Workshop.
  53. H. Ramampiaro, (2006), "Supporting Collborative Mobile Applications using Adaptable Transactional Framework". IEEE Proceedings of 2nd International Conference on Collaborative Computing, Atlanta, GA, USA. IEEE.
  54. V. Beisvag, F. Jünge, H. Bergum, C.C. Günther, M. Langaas, H. Ramampiaro, and A. Lægreid, (2005), "GeneTools: Resources for Functional Annotations". 8th International Meeting of the Microarray Gene Expression Data Society.
  55. A.I. Wang, C.F Sørensen, H.N. Le, H. Ramampiaro, R. Conradi and M. Nygård, (2005), "Using the MOWAHS Characterisation Framework for Development of Mobile Work Applications". Proceedings of the 6th International Conference on Product Focused Software Process Improvment (PROFES 2005). LNCS Springer Verlag.
  56. H. Ramampiaro, (2004), "Transactional Support for Cooperative Work: Using Mobile Agents in CAGISTrans". Proceedings of the International Conference on Parallel and Distributed Systems (PDCS 2004), MIT Cambridge.. ACTA Press.
  57. H.N. Le, M. Nygård and H. Ramampiaro, (2004), "A Locking Model for Mobile Databases in Mobile Environments". Proceedings of the International Conference DATABASES AND APPLICATIONS 2004, Innsbruck. ACTA Press.
  58. H. Ramampiaro, A.I. Wang, C.F Sørensen, H.N. Le, R. Conradi and M. Nygård , (2003), "Requirement Indicators for Mobile Work: The MOWAHS Approach". Proceedings of the International Symposia on Applied Informatics (AI2003), Innsbruck. ACTA Press.
  59. C.F Sørensen, A.I. Wang, H.N. Le, H. Ramampiaro, M. Nygård and R. Conradi, (2002), "The MOWAHS Characterisation Framework for Mobile Work". Proceedings of the International Symposia on Applied Informatics (AI2002), Innsbruck. ACTA Press.
  60. H. Ramampiaro and M. Nygård, (2002), "Supporting customisable transactions for cooperative work: An experience paper". Proceedings of the Collaborative Technologies Symposium 2002 (CTS 2002), San Antonio. ISCA.
  61. H. Ramampiaro and M. Nygård, (2001), "CAGISTrans: Providing adaptable transactional support for cooperative work". Proceedings of the 6th INFORMS Conference on Information Systems and Technology (CIST 2001), pp. 3-29, Florida. INFORM. Selected for publication in the special issue of Information Technology & Management (ITM) Journal.
  62. H. Ramampiaro and M. Nygård, (2001), "CAGISTrans: A transactional framework for cooperative work". Proceedings of the 14th International Conference on Parallel and Distributed Computing Systems (ISCAPDCS 2001), pp. 43-50, Dallas. ISCA.
  63. H. Ramampiaro, A.I. Wang and T. Brasethvik, (2000), "Supporting distributed cooperative work in CAGIS". Proceedings of 4th International Conference on Software Engineering and Applications (SEA 2000). ACTA Press.
  64. H. Ramampiaro and M. Nygård, (1999), "Cooperative database system: A constructive review of cooperative transaction models". Proceedings of the 1999 International Symposium on Database Application in Non-Traditional Environment (DANTE 99), pages 315-324. IEEE CS Press.
  65. H. Ramampiaro, M. Divitini, S. A. Petersen, (1999), "Agent-based groupware: Challenges for cooperative transaction models". J. Estublier et. al, editors, Proceedings of the International Process Technology Workshop (IPTW 99). Pages 18-22, Villard de Lens.
  66. Theses/Books/Book Chapters

  67. H. Ramampiaro, H. Langseth, M. Havig, H. Schistad, T. Almenningen and H. T. Nguyen, (2019), "New Ideas in ranking for Personalised Fashion Recommender Systems". In In P. Moscato and N. J. de Vries (eds.), Business and Consumer Analytics: New Directions, Vol. 1 and 2. Chap. 25, pp. 977-1010. ISBN 978-3-030-06222-4. Springer [BIB] .
  68. A.I. Wang, C.F Sørensen, H.N. Le, H. Ramampiaro, M. Nygård and R. Conradi, (2009), "From Scenarios to Requirements in Mobile Client-Server Systems". In Designing Software-Intensive Systems: Methods and Principles. IDEA Group Publishing/IGI Global Publisher.
  69. H. Ramampiaro, (2001), "CAGISTrans: Adaptable Transactional Support for Cooperative Work". In Norges teknisk- naturvitenkapelig universitet (NTNU), Dr.Ing. Thesis. NTNU 2001:94, IDI-nr. 6/2001. NTNU.
  70. H. Ramampiaro, (1997), "Exact Algorithms for Texture Classification". In Stavanger University College, Masters Thesis. Stavanger University College.
  71. Invited Talks

  72. H. Ramampiaro, (2018), "AI: Skal vi omfavne eller frykte det? (AI: Should we embrace or fear it?)". In IKT-Norges årskonferanse / ICT Norway's Yearly Conference (NEO2018).
  73. H. Ramampiaro, (2014), "Hvordan gjør jeg forelesningene attraktive for studentene? (How do I make the lectures attractive for my students?) ". In IDIs Instituttseminar.
  74. H. Ramampiaro, (2014), "Visualizing BigData for knowledge and information extraction". In Sinett Symposium 2014 organized by the Norwegian Defence Research Establishment (FFI), Oslo.
  75. H. Ramampiaro, (2013), "Big Data i offentlig bruk og gjenbruk (Big Data in the Public Sector)". In Norsk Konferanse for IKT i offentlig sektor (NOKIOS 2013), Trondheim.
  76. H. Ramampiaro, (2007), "Text Mining Techniques and Methods for Biomedical Information". In LCB Seminar Series, BMC, University of Uppsala, Sweden.
  77. H. Ramampiaro, (2002), "On support of mobile collaborative work: The MOWAHS Approach". In CyberCamp 2002, Trondheim.
  78. Technical Reports / Other Publications

  79. GK Pitsilis, H. Ramampiaro, H Langseth, (2018), "Detecting Offensive Language in Tweets Using Deep Learning". In arXiv preprint arXiv:1801.04433. [PDF] [BIB] .
  80. B Agarwal, H. Ramampiaro, H Langseth, M Ruocco, (2017), "A Deep Network Model for Paraphrase Detection in Short Text Messages". In arXiv preprint arXiv:1712.02820. [PDF] [BIB] .
  81. J. Joshi, E. Bertino, C. Pu and Heri Ramampiaro, (2012), "ACM/Springer Mobile Networks and Applications (MONET) Special Issue on Collaborative Computing: Networking, Applications and Worksharing". In Mobile Networks and Applications (MONET), 17(3), pp. 325-326. Springer. (Editorial) [DOI].
  82. H. Ramampiaro, D. Cruzes, R. Conradi, and M. Mendonça, (2009), "Information Retrieval Support for Evidence-Based Software Engineering". In ERCIM Data and Information Spaces Workshop, Paris. ERCIM.
  83. H. Ramampiaro and M. Nygård, (2001), "CAGISTrans: Supporting Cooperation among Agents using Customisable Transaction Models". In Norwegian University of Science and Technology, Technical Paper IDI-nr. 5/2001.
  84. H. Ramampiaro and M. Nygård, (1999), "Transaction support for cooperative environments: A state-of-the-art". In Norwegian University of Science and Technology, Technical Paper IDI-nr. 10/99.
  85. H. Ramampiaro, (1997), "Optimal Texture Classification Algorithm". In Norwegian Numerical Meeting (NNM 99), Os, Bergen.