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Dr Jan Hidders

Positions held:
  • Lecturer, School of Computing and Mathematical Sciences
Address

Room 156, Malet Street

Email
Tel
  • Overview

    Overview

    ORCID

    0000-0002-8865-4329
  • Research

    Research

    Research interests

    • Graph data management
    • Workflow modelling and orchestration
    • Conceptual data models

    Research overview

    Graph data management

    My research covers several theoretical and more applied topics within graph data management. An important one is that of graph query languages, both their design and theoretical properties (such as expressive power) but also practical issues such as their efficient implementation, including aspects such as query optimisation and indexing. Another topic is that of graph-based data models, where there is a certain type of schema definition language that specifies what is and is not allowed in a certain graph database, or in other words specifies what the instance graph is allowed to look like. I study the design of such schema definition languages, which includes theoretical properties such as the computational complexity of checking them and reasoning over them. I am closely involved in the development of the schema definition language that is being added to SQL for graph data management, and as such am active with LDBC to represent Birkbeck. My research also includes how schemas can be used for typing queries formulated in a graph language, in order to detect errors in query specifications or understand what kind of results can be expected from certain graph queries over graphs that conform to a certain schema. This research also investigates how the different schema definition languages that have been developed for RDF and LPG (Labelled Property Graphs) compare with each other, both in practice and in theory.

    Workflow modelling and orchestration

    In my workflow research I focus on a special class of Petri-nets for representing workflows and similar processes. In particular I am interested in using the notion of hierarchy is such nets. This includes for example ways to hierarchically generate and design workflow nets that they then have desirable properties in terms of correctness (such as soundness) and understandability by human beings. We also look at the reverse, where a given large and complex workflow net is hierarchically decomposed, so that it becomes easier to algorithmically test and decide certain desirable properties, and in addition becomes easier for human beings to understand.

    In my research I also look at workflow orchestration, and especially look at the problem of deciding and characterising of a certain orchestration specification that describes what is considered to be a correct interaction between several independent actors via messages, can indeed be implemented such only correct interactions happen.

    Conceptual data models

    I am interested in the formal semantics of conceptual data models, and specifically in the formal semantics of ORM2. As part of this research I'm involved in an effort to formalise that semantics of ORM2 as a mapping to a restricted fragment first order logic. This research also involves investigating the relationship of ORM2 with other data models, and in particular the graph data models that are currently popular. Another subtopic is that of designing an ORM2-native DBMS, where we look as issues such as the design of an appropriate query language, as well as identifying opportunities for query and storage optimisation that benefits form the high-level abstraction that ORM2 offers as a data model.

    Research Centres and Institutes

  • Supervision and teaching

    Supervision and teaching

    Teaching

    Teaching modules

    • Software Engineering II (BUCI067H6)
    • Computer Systems (COIY060H7)
  • Publications

    Publications

    Article

    • Angles, R. and Bonifati, A. and Dumbrava, S. and Fletcher, G. and Green, A. and Hidders, Jan and Li, B. and Libkin, L. and Marsault, V. and Martens, W. and Murlak, F. and Plantikow, S. and Savkovic, O. and Schmidt, M. and Sequeda, J. and Staworko, S. and Tomaszuk, D. and Voigt, H. and Vrgoc, D. and Wu, M. and Zivkovic, D. (2023) PG-Schema: schemas for property graphs. Proceedings of the ACM on Management of Data 1 (2), pp. 198:1-198:25. ISSN 2836-6573.
    • Bonifati, A. and Dumbrava, S. and Fletcher, G. and Hidders, Jan and Hofer, M. and Martens, W. and Murlak, F. and Shinavier, J. and Staworko, S. and Tomaszuk, D. (2023) Threshold Queries. SIGMOD Record 52 (1), pp. 64-73. ISSN 0163-5808.
    • Sakr, S. and Bonifati, A. and Voigt, H. and Iosup, A. and Ammar, K. and Angles, R. and Aref, W. and Arenas, M. and Besta, M. and Boncz, P.A. and Daudjee, K. and Valle, E.D. and Dumbrava, S. and Hartig, O. and Haslhofer, B. and Hegeman, T. and Hidders, Jan and Hose, K. and Iamnitchi, A. and Kalavri, V. and Kapp, H. and Martens, W. and Özsu, M.T. and Peukert, E. and Plantikow, S. and Ragab, M. and Ripeanu, M.R. and Salihoglu, S. and Schulz, C. and Selmer, P. and Sequeda, J. F. and Shinavier, J. and Szárnyas, G. and Tommasini, R. and Tumeo, A. and Uta, A. and Varbanescu, A.L. and Wu, H.-Y. and Yakovets, N. and Yan, D. and Yoneki, E. (2021) The future is big graphs. Communications of the ACM 64 (9), pp. 62-71. ISSN 0001-0782.
    • Sroka, J. and Hidders, Jan (2017) On determining the AND-OR hierarchy in workflow nets. Fundamenta Informaticae 156 (1), pp. 95-123. ISSN 0169-2968.
    • Litak, T. and Mikulás, Szabolcs and Hidders, Jan (2016) Relational lattices: from databases to Universal Algebra. Journal of Logical and Algebraic Methods in Programming 85 (4), pp. 540-573. ISSN 2352-2208.
    • Hidders, Jan and Michiels, P. and Paredaens, J. and Vercammen, R. (2005) Lixquery: a formal foundation for xquery research. SIGMOD Record 34 (4), pp. 21-26. ISSN 0163-5808.
    • Hidders, Jan and Michiels, P. and Vercammen, R. (2005) Optimizing sorting and duplicate elimination in xquery path expressions. Bulletin of the European Association for Theoretical Computer Science 86, pp. 199-223. ISSN 0252–9742.
    • Dekeyser, S. and Hidders, Jan and Paredaens, J. (2004) A transaction model for XML databases. World Wide Web: Internet and Web Information Systems 7 (1), pp. 29-57. ISSN 1386-145X.

    Book

    Book Section

    • Boneva, I. and Groz, B. and Hidders, Jan and Murlak, F. and Staworko, S. (2023) Static analysis of graph database transformations. In: PODS '23: Proceedings of the 42nd ACM SIGMOD-SIGACT-SIGAI Symposium on Principles of Database Systems. ACM. pp. 251-261. ISBN 9798400701276.
    • Bonifati, A. and Dumbrava, S. and Fletcher, G. and Hidders, Jan and Hofer, M. and Martens, W. and Murlak, F. and Shinavier, J. and Staworko, S. and Tomaszuk, D. (2022) Threshold queries in theory and in the wild. In: Özcan, F. and Freire, J. and Lin, X. (eds.) Proceedings of the VLDB Endowment. VLDB Endowment. pp. 1105-1118.
    • Aamer, H. and Hidders, Jan and Paredaens, J. and Bussche, J.V.d. (2021) Expressiveness within Sequence Datalog. In: PODS'21: Proceedings of the 40th ACM SIGMOD-SIGACT-SIGAI Symposium on Principles of Database Systems. ACM. pp. 70-81. ISBN 9781450383813.
    • Angles, R. and Bonifati, A. and Dumbrava, S. and Fletcher, G. and Hare, K.W. and Hidders, Jan and Lee, V.E. and Li, B. and Libkin, L. and Martens, W. and Murlak, F. and Perryman, J. and Savkovic, O. and Schmidt, M. and Sequeda, J.F. and Staworko, S. and Tomaszuk, D. (2021) PG-Keys: keys for property graphs. In: SIGMOD '21: Proceedings of the 2021 International Conference on Management of Data. ACM. pp. 2423-2436. ISBN 9781450383431.
    • Hartig, Olaf and Hidders, Jan (2019) Defining schemas for property graphs by using the GraphQL Schema Definition Language. In: GRADES-NDA'19: Proceedings of the 2nd Joint International Workshop on Graph Data Management Experiences & Systems (GRADES) and Network Data Analytics (NDA). ACM. pp. 6:1-6:11. ISSN 978-1-4503-6789-9/19/06. ISBN 9781450367899.
    • Poulovassilis, Alexandra (2018) Applications of flexible querying to graph data. In: Fletcher, G.H.L. and Hidders, Jan and Larriba-Pey, J.L. (eds.) Graph Data Management: Fundamental Issues and Recent Developments. Data-Centric Systems and Applications (DCSA). Springer. pp. 97-142. ISBN 9783319961927.
    • Picalausa, F. and Fletcher, G.H.L. and Hidders, Jan and Vansummeren, S. (2014) Principles of Guarded Structural Indexing. In: Schweikardt, N. and Christophides, V. and Leroy, V. (eds.) Proc. 17th International Conference on Database Theory (ICDT), Athens, Greece, March 24-28, 2014.. Openproceedings.org. pp. 245-256. ISSN 978-3-89318066-1. ISBN 9783893180661.
    • Hidders, Jan and Kwasnikowska, N. and Sroka, J. and Tyszkiewicz, J. and Van den Bussche, J. (2007) A formal model of dataflow repositories. In: Cohen Boulakia, S. and Tannen, V. (eds.) Data Integration in the Life Sciences: 4th International Workshop. Lecture Notes in Computer Science. Springer. pp. 105-121. ISBN 9783540732549.
    • Hidders, Jan and Michiels, P. and Simeon, J. and Vercammen, R. (2007) How to recognise different kinds of tree patterns from quite a long way away. In: PLAN-X: 2007, Programming Language Technologies for XML. Association for Computing Machinery. pp. 14-24.
    • Calders, T. and Dekeyser, S. and Hidders, Jan and Paredaens, J. (2006) Analyzing workflows implied by instance-dependent access rules. In: Vansummeren, S. (ed.) Proceedings of the Twenty-Fifth ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems. Association for Computing Machinery. pp. 100-109. ISBN 9781595933188.
    • Dekeyser, S. and Hidders, Jan and Watson, R. and Addie, R. (2006) Peer-to-peer form based web information systems. In: Dobbie, G. and Bailey, J. (eds.) Database Technologies 2006: Proceedings of the 17th Australasian Database Conference. CRPIT. Australian Computer Society. pp. 79-88. ISBN 9781920682316.
    • Hidders, Jan and Paredaens, J. and Vercammen, R. (2006) On the expressive power of xquery-based update languages. In: Amer-Yahia, S. and Bellahsene, Z. and Hunt, E. and Unland, R. and Yu, J.X. (eds.) Database and XML Technologies: 4th International XML Database Symposium. Lecture Notes in Computer Science. Springer. pp. 92-106. ISBN 9783540388777.
    • Vercammen, R. and Hidders, Jan and Paredaens, J. (2006) Query translation for xpath-based security views. In: Grust, T. and Hopfner, H. and Illarramendi, A. and Jablonski, S. and Mesiti, M. and Muller, S. and Patranjan, P.-L. and Sattler, K.-U. and Spiliopoulou, M. and Wijsen, J. (eds.) International Conference on Extending Database Technology: Current Trends in Database Technology. Lecture Notes in Computer Science. Springer. pp. 250-263. ISBN 9783540467885.
    • Fernandez, M.F. and Hidders, Jan and Michiels, P. and Simeon, J. and Vercammen, R. (2005) Optimizing sorting and duplicate elimination in xquery path expressions. In: Viborg Andersen, K. and Debenham, J.K. and Wagner, R.R. (eds.) Database and Expert Systems Applications: 16th International Conference. Lecture Notes in Computer Science. Springer. pp. 554-563. ISBN 9783540285663.
    • Hidders, Jan and Dumas, M. and van der Aalst, W.M.P. and ter Hofstede, A.H.M. and Verelst, J. (2005) When are two workflows the same?. In: Atkinson, M.D. and Dehne, F.K.H.A. (eds.) Theory of Computing: The Australasian Theory Symposium 2005. CRPIT. Australian Computer Society. pp. 3-11.
    • Hidders, Jan and Kwasnikowska, N. and Sroka, J. and Tyszkiewicz, J. and Van den Bussche, J. (2005) Petri net + nested relational calculus = dataflow. In: Meersman, R. and Tari, Z. and Hacid, M.-S. and Mylopoulos, J. and Pernici, B. and Babaoglu, O. and Jacobsen, H.-A. and Loyall, J.P. and M., Kifer and Spaccapietra, S. (eds.) On the Move to Meaningful Internet Systems 2005. Lecture Notes in Computer Science. Springer. pp. 220-237. ISBN 9783540297369.
    • Hidders, Jan and Marrara, S. and Paredaens, J. and Vercammen, R. (2005) On the expressive power of xquery fragments. In: Bierman, G.M. and Koch, C. (eds.) Database Programming Languages: 10th International Symposium. Lecture Notes in Computer Science. Springer. pp. 154-168. ISBN 9783540309512.
    • Hidders, Jan and Paredaens, J. and Thiran, P. and Houben, G.-J. and van Hee, K.-M. (2005) Non-destructive integration of form-based views. In: Eder, J. and Haav, H.-M. and Kalja, A. and Penjam, J. (eds.) Advances in Databases and Information Systems: 9th East European Conference, ADBIS 2005. Lecture Notes in Computer Science. Springer. pp. 74-86. ISBN 9783540285854.
    • Le Page, W. and Hidders, Jan and Michiels, P. and Paredaens, J. and Vercammen, R. (2005) On the expressive power of node construction in xquery. In: Doan, A. and Neven, F. and McCann, R. and Bex, G.J. (eds.) Proceedings of the Eight International Workshop on the Web & Databases: WebDB 2005. Association for Computing Machinery. pp. 85-90.
    • Dekeyser, S. and Hidders, Jan (2004) Conflict scheduling of transactions on XML documents. In: Schewe, K.-D. and Williams, H.E. (eds.) Database Technologies 2004: Proceedings of the Fifteenth Australasian Database Conference. CRPIT. Australian Computer Society. pp. 93-101.
    • Hidders, Jan and Paredaens, J. and Vercammen, R. and Demeyer, S. (2004) A light but formal introduction to xquery. In: Bellahsene, Z. and Milo, T. and Rys, M. and Suciu, D. and Unland, R. (eds.) Database and XML Technologies, Second International XML Database Symposium. Lecture Notes in Computer Science. Springer. pp. 5-20. ISBN 9783540229698.
    • Dekeyser, S. and Hidders, Jan (2003) A commit scheduler for XML databases. In: Zhou, X. and Zhang, Y. and Orlowska, M.E. (eds.) Web Technologies and Applications: 5th Asian-Pacific Web Conference. Lecture Notes in Computer Science. Springer. pp. 83-88. ISBN 9783540023548.
    • Dekeyser, S. and Hidders, Jan and Paredaens, J. (2003) Instance independent concurrency control for semistructured databases. In: Flesca, S. and Greco, S. and Saccaand, D. and Zumpano, E. (eds.) Proceedings of the Eleventh Italian Symposium on Advanced Database Systems: SEBD 2003. Rubettino Editore. pp. 323-324.
    • Hidders, Jan (2003) Satisfiability of xpath expressions. In: Lausen, G. and Suciu, D. (eds.) Database Programming Languages: 9th International Workshop. Lecture Notes in Computer Science. Springer. pp. 21-36. ISBN 9783540208969.
    • Hidders, Jan (2003) Typing graph-manipulation operations. In: Calvanese, D. and Lenzerini, M. and Motwani, R. (eds.) Database Theory: ICDT 2003. Lecture Notes in Computer Science. Springer. pp. 391-406. ISBN 9783540003236.
    • Hidders, Jan and Michiels, P. (2003) Avoiding unnecessary ordering operations in xpath. In: Lausen, G. and Suciu, D. (eds.) Database Programming Languages: 9th International Workshop. Lecture Notes in Computer Science. Springer. pp. 54-70. ISBN 9783540208969.
    • Bielecki, M. and Hidders, Jan and Paredaens, J. and Tyszkiewicz, J. and Van den Bussche, J. (2002) Navigating with a browser. In: Widmayer, P. and Triguero Ruiz, F. and Morales Bueno, R. and Hennessy, M. and Eidenbenz, S.J. and Conejo, R. (eds.) Automata, Languages and Programming: 29th International Colloquium. Lecture Notes in Computer Science. Springer. pp. 764-775. ISBN 9783540438649.
    • Dekeyser, S. and Hidders, Jan (2002) Path locks for XML document collaboration. In: Wang Ling, T. and Dayal, U. and Bertino, E. and Ng, W.K. and Goh, A. (eds.) 3rd International Conference on Web Information Systems Engineering: WISE 2002. IEEE Computer Society. pp. 105-114. ISBN 9780769517668.
    • Hidders, Jan (1995) Union-types in object-oriented schemes. In: Atzeni, P. and Tannen, V. (eds.) Database Programming Languages, DBPL-5: Proceedings of the Fifth International Workshop on Database Programming Languages. Electronic Workshops in Computing. Springer.
    • Hidders, Jan and Paredaens, J. (1993) GOAL: a graph-based object and association language. In: Paredaens, J. and Tenenbaum, L.A. (eds.) Advances in Database Systems: Implementations and Applications. CISM International Centre for Mechanical Sciences: Courses and Lectures. Springer. pp. 247-265.

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