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Semantic Faceted Search with Aggregation and Recursion [chapter]

Evgeny Sherkhonov, Bernardo Cuenca Grau, Evgeny Kharlamov, Egor V. Kostylev
2017 Lecture Notes in Computer Science  
Faceted search is the de facto approach for exploration of data in e-commerce: it allows users to construct queries in an intuitive way without a prior knowledge of formal query languages. This approach has been recently adapted to the context of RDF. Existing faceted search systems however do not allow users to construct queries with aggregation and recursion which poses limitations in practice. In this work we extend faceted search over RDF with these functionalities and study the
more » ... g query language. In particular, we investigate complexity of the query answering and query containment problems.
doi:10.1007/978-3-319-68288-4_35 fatcat:5dq5yzpt55bwja53p5dndydfjm

Answering Queries using Views over Probabilistic XML: Complexity and Tractability [article]

Bogdan Cautis, Evgeny Kharlamov
2012 arXiv   pre-print
Kharlamov was supported by ERC FP7 grant Webdam (n. 226513), EU project ACSI (FP7-ICT-257593), EPSRC grant EP/G004021/1.  ... 
arXiv:1208.0078v1 fatcat:bs653lo6dzh6ziif4ays33aqsm

Ranking, Aggregation, and Reachability in Faceted Search with SemFacet

Evgeny Kharlamov, Luca Giacomelli, Evgeny Sherkhonov, Bernardo Cuenca Grau, Egor V. Kostylev, Ian Horrocks
2017 International Semantic Web Conference  
dblp:conf/semweb/KharlamovGSGKH17 fatcat:faflxfla2vhlxgrxnxzz2cin24

GRAND+: Scalable Graph Random Neural Networks [article]

Wenzheng Feng, Yuxiao Dong, Tinglin Huang, Ziqi Yin, Xu Cheng, Evgeny Kharlamov, Jie Tang
2022 arXiv   pre-print
Graph neural networks (GNNs) have been widely adopted for semi-supervised learning on graphs. A recent study shows that the graph random neural network (GRAND) model can generate state-of-the-art performance for this problem. However, it is difficult for GRAND to handle large-scale graphs since its effectiveness relies on computationally expensive data augmentation procedures. In this work, we present a scalable and high-performance GNN framework GRAND+ for semi-supervised graph learning. To
more » ... ress the above issue, we develop a generalized forward push (GFPush) algorithm in GRAND+ to pre-compute a general propagation matrix and employ it to perform graph data augmentation in a mini-batch manner. We show that both the low time and space complexities of GFPush enable GRAND+ to efficiently scale to large graphs. Furthermore, we introduce a confidence-aware consistency loss into the model optimization of GRAND+, facilitating GRAND+'s generalization superiority. We conduct extensive experiments on seven public datasets of different sizes. The results demonstrate that GRAND+ 1) is able to scale to large graphs and costs less running time than existing scalable GNNs, and 2) can offer consistent accuracy improvements over both full-batch and scalable GNNs across all datasets.
arXiv:2203.06389v1 fatcat:vt27na7majg3bo6hatxzygiwvm

On Expansion and Contraction of DL-Lite Knowledge Bases [article]

Dmitriy Zheleznyakov, Evgeny Kharlamov, Werner Nutt, Diego Calvanese
2020 arXiv   pre-print
Email addresses: d.zheleznyakov@ocado.com (Dmitriy Zheleznyakov), evgeny.kharlamov@cs.ox.ac.uk (Evgeny Kharlamov), Werner.Nutt@unibz.it (Werner Nutt), Diego.Calvanese@unibz.it (Diego Calvanese) 1 http:  ... 
arXiv:2001.09365v1 fatcat:5mfrk3paqfc5dftarmm4jdd6ti

Incompleteness in information integration

Evgeny Kharlamov, Werner Nutt
2008 Proceedings of the VLDB Endowment  
Information integration is becoming a critical problem for both businesses and individuals. The data, especially the one that comes from the Web, is naturally incomplete, that is, some data values may be unknown or lost because of communication problems, hidden due to privacy considerations. At the same time research in (virtual) integration in the community focusses on null-free sources and addresses limited forms of incompleteness only. In our work we aim to extend current results on virtual
more » ... ntegration by considering various forms of incompleteness at the level of the sources, the integrated database and the queries (we call this Incomplete Information Integration, or III). More specifically, we aim to extend current query answering techniques for local-, and global-as-view integration to integration of tables with SQL nulls, Codd tables, etc. We also aim to consider incomplete answers as a natural extension of the classical approach. Our main research issues are (i) semantics of III, (ii) semantics of query answering in III, (iii) complexity of query answering, and (iv) algorithms (possibly approximate) to compute the answers.
doi:10.14778/1454159.1454242 fatcat:rgx2mzysdjfczpz5nskpb7mvmq

A Proof Theory for DL-Lite

Diego Calvanese, Evgeny Kharlamov, Werner Nutt
2007 International Workshop on Description Logics  
In this work we propose an alternative approach to inference in DL-Lite, based on a reduction to reasoning in an extension of function-free Horn Logic (EHL). We develop a calculus for EHL and prove its soundness and completeness. We also show how to achieve decidability by means of a specific strategy, and how alternative strategies can lead to improved results in specific cases. On the one hand, we propose a strategy that mimics the query-answering technique based on first computing a query
more » ... riting and then evaluating it. On the other hand, we propose strategies that allow one to anticipate the grounding of atoms, and that might lead to better performance in the case where the size of the TBox is not dominated by the size of the data.
dblp:conf/dlog/CalvaneseKN07 fatcat:wupcnyj5czeozlvneieb6kqfe4

QUASAR

Luying Chen, Michael Benedikt, Evgeny Kharlamov
2012 Proceedings of the 15th International Conference on Extending Database Technology - EDBT '12  
doi:10.1145/2247596.2247680 dblp:conf/edbt/ChenBK12 fatcat:xkv56wt3mbav3pbcfa5ustbnvm

Verification of Inconsistency-Aware Knowledge and Action Bases (Extended Version) [article]

Diego Calvanese, Evgeny Kharlamov, Marco Montali, Ario Santoso, Dmitriy Zheleznyakov
2013 arXiv   pre-print
Description Logic Knowledge and Action Bases (KABs) have been recently introduced as a mechanism that provides a semantically rich representation of the information on the domain of interest in terms of a DL KB and a set of actions to change such information over time, possibly introducing new objects. In this setting, decidability of verification of sophisticated temporal properties over KABs, expressed in a variant of first-order mu-calculus, has been shown. However, the established framework
more » ... treats inconsistency in a simplistic way, by rejecting inconsistent states produced through action execution. We address this problem by showing how inconsistency handling based on the notion of repairs can be integrated into KABs, resorting to inconsistency-tolerant semantics. In this setting, we establish decidability and complexity of verification.
arXiv:1304.6442v1 fatcat:bxfcze4ypnhvrf2tm26je3qvd4

Controlled Query Evaluation for Datalog and OWL 2 Profile Ontologies [article]

Bernardo Cuenca Grau, Evgeny Kharlamov, Egor V. Kostylev, Dmitriy Zheleznyakov
2015 arXiv   pre-print
., 2013] Bernardo Cuenca Grau, Evgeny Kharlamov, Egor V. Kostylev, and Dmitriy Zheleznyakov. Controlled Query Evaluation over OWL 2 RL Ontologies. In ISWC, pages 49-65, 2013.  ... 
arXiv:1504.06529v1 fatcat:ulbllyfh25ggpizvkdd3n7mqoa

Evolution of DL − Lite Knowledge Bases [chapter]

Diego Calvanese, Evgeny Kharlamov, Werner Nutt, Dmitriy Zheleznyakov
2010 Lecture Notes in Computer Science  
We study the problem of evolution for Knowledge Bases (KBs) expressed in Description Logics (DLs) of the DL-Lite family. DL-Lite is at the basis of OWL 2 QL, one of the tractable fragments of OWL 2, the recently proposed revision of the Web Ontology Language. We propose some fundamental principles that KB evolution should respect. We review known model and formula-based approaches for evolution of propositional theories. We exhibit limitations of a number of model-based approaches: besides the
more » ... act that they are either not expressible in DL-Lite or hard to compute, they intrinsically ignore the structural properties of KBs, which leads to undesired properties of KBs resulting from such an evolution. We also examine proposals on update and revision of DL KBs that adopt the model-based approaches and discuss their drawbacks. We show that known formula-based approaches are also not appropriate for DL-Lite evolution, either due to high complexity of computation, or because the result of such an action of evolution is not expressible in DL-Lite. Building upon the insights gained, we propose two novel formula-based approaches that respect our principles and for which evolution is expressible in DL-Lite. For our approaches we also developed polynomial time algorithms to compute evolution of DL-Lite KBs.
doi:10.1007/978-3-642-17746-0_8 fatcat:pkgiifrbhbdplammyurrqnnw6a

Navigating OWL 2 Ontologies Through Graph Projection [chapter]

Ahmet Soylu, Evgeny Kharlamov
2019 Communications in Computer and Information Science  
Ontologies are powerful, yet often complex, assets for representing, exchanging, and reasoning over data. Particularly, OWL 2 ontologies have been key for constructing semantic knowledge graphs. Ability to navigate ontologies is essential for supporting various knowledge engineering tasks such as querying and domain exploration. To this end, in this short paper, we describe an approach for projecting the nonhierarchical topology of an OWL 2 ontology into a graph. The approach has been
more » ... d in two tools, one for visual query formulation and one for faceted search, and evaluated under different use cases.
doi:10.1007/978-3-030-14401-2_10 fatcat:4ybzbidqnneyjpobjawdkwdpbm

Capturing Instance Level Ontology Evolution for DL-Lite [chapter]

Evgeny Kharlamov, Dmitriy Zheleznyakov
2011 Lecture Notes in Computer Science  
Actually, ABox update algorithm cannot exist since Calvanese, Kharlamov, Nutt, and Zheleznyakov showed that DL-Lite is not closed under L a ⊆ [11] .  ... 
doi:10.1007/978-3-642-25073-6_21 fatcat:372g6ucdrbee5n52faxjqiqkaa

Scaling ML Analytics with Knowledge Graphs: A BoschWelding Case

Baifan Zhou, Dongzhuoran Zhou, Jieying Chen, Yulia Svetachova, Gong Cheng, Evgeny Kharlamov
2021 Zenodo  
Automated welding is heavily used in automotive industry to produce car bodies by connecting metal parts with welding spots. Modern welding solutions and manufacturing environments produce high volume of heterogeneous data. Analytics of these data with machine learning (ML) can help to ensure high quality of welding operations. However, due to heterogeneity of data and application scenarios, scaling such ML-based analytics is challenging. We address this challenge by relying on knowledge graphs
more » ... (KG) that not only conveniently allow to integrate welding data, but also to serve as the bases for layering ML-based analytical applications, thus enabling quality monitoring of welding operations. In this work we focus on construction of a KG for welding that is tailored towards further use for ML applications. Furthermore, we demonstrate how selected ML analytical tasks are supported by this KG.
doi:10.5281/zenodo.6797514 fatcat:qjbiduvj2bbjhetervtcq5hlii

Updating probabilistic XML

Evgeny Kharlamov, Werner Nutt, Pierre Senellart
2010 Proceedings of the 1st International Workshop on Data Semantics - DataSem '10  
We investigate the complexity of performing updates on probabilistic XML data for various classes of probabilistic XML documents of different succinctness. We consider two elementary kinds of updates, insertions and deletions, that are defined with the help of a locator query that specifies the nodes where the update is to be performed. For insertions, two semantics are considered, depending on whether a node is to be inserted once or for every match of the query. We first discuss deterministic
more » ... updates over probabilistic XML, and then extend the algorithms and complexity bounds to probabilistic updates. In addition to a number of intractability results, our main result is an efficient algorithm for insertions defined with branching-free queries over probabilistic models with local dependencies. Finally, we discuss the problem of updating probabilistic XML databases with continuous probability distributions.
doi:10.1145/1754239.1754264 dblp:conf/edbtw/KharlamovNS10 fatcat:2jlhhs4sdrcjtgiiajzdileeua
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