The Experts below are selected from a list of 957 Experts worldwide ranked by ideXlab platform
Yoon Joon Lee - One of the best experts on this subject based on the ideXlab platform.
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Filtering Xpath Expressions for XML access control
Computers & Security, 2004Co-Authors: Jae-myeong Jeon, Yon Dohn Chung, Myoung Ho Kim, Yoon Joon LeeAbstract:Xpath is a standard for specifying parts of XML documents and a suitable language for both query processing and access control of XML. In this paper, we use the Xpath Expression for representing user queries and access control for XML. And we propose an access-control method for XML, where we control accesses to XML documents by filtering query Xpath Expressions through access-control Xpath Expressions. For filtering the access-denied parts out of query Xpath Expressions, set operations (such as, intersection and difference) between the Xpath Expressions are essential. However, it is known that the containment problem of two Xpath Expressions is coNP-hard when the Xpath Expressions contain predicates (or branch), wildcards and descendant axes. To solve the problem, we directly search XACT (XML Access Control Tree) for a query Xpath Expression and extract the access-granted parts. The XACT is our proposed structure, where the edges are structural summary of XML elements and the nodes contain access-control information. We show that the query Xpath Expressions are successfully filtered through the XACT by our proposed method, and also show the performance improvement by comparing the proposed method with the previous work.
Hansarno Jacobsen - One of the best experts on this subject based on the ideXlab platform.
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gpx matcher a generic boolean predicate based Xpath Expression matcher
Extending Database Technology, 2011Co-Authors: Mohammad Sadoghi, Ioana Burcea, Hansarno JacobsenAbstract:Content-based architectures for XML data dissemination are gaining increasing attention both in academia and industry. These dissemination networks are the building blocks of selective information dissemination applications which have wide applicability such as sharing and integrating information in both scientific and corporate domains. At the heart of these dissemination services is a fast engine for matching of an incoming XML message against stored Xpath Expressions to determine interested consumers for the message. To achieve the ultra-low response time, predominant in financial message processing, the Xpath Expression matching must be done efficiently. In this paper, we develop and evaluate a novel algorithm based on a unique encoding of Xpath Expressions and XML messages, unlike dominating automaton-based algorithms, for efficiently solving this matching problem. We demonstrate a matching time in the millisecond range for millions of Xpath Expressions which significantly outperforms state-of-the-art algorithms.
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EDBT - GPX-matcher: a generic boolean predicate-based Xpath Expression matcher
Proceedings of the 14th International Conference on Extending Database Technology - EDBT ICDT '11, 2011Co-Authors: Mohammad Sadoghi, Ioana Burcea, Hansarno JacobsenAbstract:Content-based architectures for XML data dissemination are gaining increasing attention both in academia and industry. These dissemination networks are the building blocks of selective information dissemination applications which have wide applicability such as sharing and integrating information in both scientific and corporate domains. At the heart of these dissemination services is a fast engine for matching of an incoming XML message against stored Xpath Expressions to determine interested consumers for the message. To achieve the ultra-low response time, predominant in financial message processing, the Xpath Expression matching must be done efficiently. In this paper, we develop and evaluate a novel algorithm based on a unique encoding of Xpath Expressions and XML messages, unlike dominating automaton-based algorithms, for efficiently solving this matching problem. We demonstrate a matching time in the millisecond range for millions of Xpath Expressions which significantly outperforms state-of-the-art algorithms.
Max Goebel - One of the best experts on this subject based on the ideXlab platform.
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Query-based Learning of Xpath Expressions
2012Co-Authors: Julien Carme, Michal Ceresna, Max GoebelAbstract:Abstract. XML is data format for storing of structured data. With fast growing usage of XML documents there is a demand to natively store the documents in XML databases and process them using XMLoptimized tools. With growing complexity of the stored XML data structures grows also the complexity of the queries used to retrieve the required information. This work analyzes application of the active learning using example-based queries to the problem of interactively constructing an Xpath Expression for querying structured data. Our results show that many well studied types of queries such as membership, subset or superset queries are extremely hard to use due to difficulties with their visualization in an example-based interaction with a human user. Equivalence queries have a natural visualization, but we show that they are not strong enough to imply polynomial learnability results
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Query-based Learning of Xpath Expressions ⋆
2012Co-Authors: Julien Carme, Michal Ceresna, Max GoebelAbstract:Abstract. This work analyzes the application of active learning using example-based queries to the problem of constructing an Xpath Expression from visual interaction with an human user. Key words: XML, tree structured data, query based learning, Xpath
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ICGI - Query-based learning of Xpath Expressions
Grammatical Inference: Algorithms and Applications, 2006Co-Authors: Julien Carme, Michal Ceresna, Max GoebelAbstract:This work analyzes the application of active learning using example-based queries to the problem of constructing an Xpath Expression from visual interaction with an human user.
Nobutaka Suzuki - One of the best experts on this subject based on the ideXlab platform.
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Information and Media Studies
2015Co-Authors: Kazuma Hasegawa, Kosetsu Ikeda, Nobutaka SuzukiAbstract:XML is a de-fact standard format on the Web. In general, schemas of XML documents are continuously updated ac-cording to changes in real world. If a schema is updated, then query Expressions have to be transformed so that they are \valid " under the updated schema, since the Expressions are no longer valid under the updated schema due to the schema update. However, this is not an easy task since many of recent schemas are large and complex and thus it is becoming difficult to know how to update the query expres-sions correctly. In this paper, we propose an algorithm for transforming Xpath Expressions according to schema evolu-tion. For an Xpath Expression p and a schema S, our algo-rithm treats both p and S as tree automata TAp and TAS, respectively. Our algorithm rst takes the product automa-ton TAR of TAp and TAS, then analyze TAR to nd the correspondence between the states of TAp and TAS. Based on this correspondence, the algorithm transforms TAp ac-cording to an update operation applied to TAS. We also show some preliminary experimental results
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Satisfiability of Simple Xpath Fragments under Duplicate-Free DTDs ∗
IEICE Transactions on Information and Systems, 2013Co-Authors: Nobutaka Suzuki, Yuji Fukushima, Kosetsu IkedaAbstract:SUMMARY In this paper, we consider the Xpath satisfiability problem under restricted DTDs called “duplicate free”. For an Xpath Expression q and a DTD D, q is satisfiable under D if there exists an XML document t such that t is valid against D and that the answer of q on t is nonempty. Evaluating an unsatisfiable Xpath Expression is meaningless, since such an Expression can always be replaced by an empty set without evaluating it. However, it is shown that the Xpath satisfiability problem is intractable for a large number of Xpath fragments. In this paper, we consider simple Xpath fragments under two restrictions: (i) only a label can be specified as a node test and (ii) operators such as qualifier ([]) and path union (∪ )a re not allowed. We first show that, for some small Xpath fragments under the above restrictions, the satisfiability problem is NP-complete under DTDs without any restriction. Then we show that there exist Xpath fragments, containing the above small fragments, for which the satisfiability problem
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Satisfiability of Simple Xpath Fragments under Duplicate-Free DTDs
IEICE Transactions on Information and Systems, 2013Co-Authors: Nobutaka Suzuki, Yuji Fukushima, Kosetsu IkedaAbstract:In this paper, we consider the Xpath satisfiability problem under restricted DTDs called “duplicate free”. For an Xpath Expression q and a DTD D, q is satisfiable under D if there exists an XML document t such that t is valid against D and that the answer of q on t is nonempty. Evaluating an unsatisfiable Xpath Expression is meaningless, since such an Expression can always be replaced by an empty set without evaluating it. However, it is shown that the Xpath satisfiability problem is intractable for a large number of Xpath fragments. In this paper, we consider simple Xpath fragments under two restrictions: (i) only a label can be specified as a node test and (ii) operators such as qualifier ([ ]) and path union (∪) are not allowed. We first show that, for some small Xpath fragments under the above restrictions, the satisfiability problem is NP-complete under DTDs without any restriction. Then we show that there exist Xpath fragments, containing the above small fragments, for which the satisfiability problem is in PTIME under duplicate-free DTDs
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DChanges - An Algorithm for Transforming Xpath Expressions According to Schema Evolution.
2013Co-Authors: Kazuma Hasegawa, Kosetsu Ikeda, Nobutaka SuzukiAbstract:XML is a de-fact standard format on the Web. In general, schemas of XML documents are continuously updated according to changes in real world. If a schema is updated, then query Expressions have to be transformed so that they are \valid" under the updated schema, since the Expressions are no longer valid under the updated schema due to the schema update. However, this is not an easy task since many of recent schemas are large and complex and thus it is becoming difficult to know how to update the query Expressions correctly. In this paper, we propose an algorithm for transforming Xpath Expressions according to schema evolution. For an Xpath Expression p and a schema S , our algorithm treats both p and S as tree automata T A p and T A S,
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WIDM - Satisfiability of simple Xpath fragments in the presence of dtds
Proceeding of the eleventh international workshop on Web information and data management - WIDM '09, 2009Co-Authors: Nobutaka Suzuki, Yuji FukushimaAbstract:For an Xpath Expression q and a DTD D, q is satisfiable under D if there exists an XML document t such that t is valid against D and that the answer of q on t is nonempty. Evaluating an unsatisfiable Xpath Expression is meaningless, since such an Expression can always be replaced by an empty set without evaluating it. However, it is shown that the Xpath satisfiability problem is intractable for a large number of Xpath fragments. In this paper, we consider simple Xpath fragments under two restrictions; (i) only a label can be specified as a node test and (ii) operators such as qualifier ([]) and union (∪) are not allowed. We first show that, for some small Xpath fragments under the above restrictions, the satisfiability problem is still NP-complete. Then we show that there exist Xpath fragments, containing the above small fragments, for which the satisfiability problem is in PTIME under duplicate-free DTDs.
Sheng-de Wang - One of the best experts on this subject based on the ideXlab platform.
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HPCC - A Data Parallel Approach to XML Parsing and Query
2011 IEEE International Conference on High Performance Computing and Communications, 2011Co-Authors: Cheng-han You, Sheng-de WangAbstract:Data-parallel XML parsing has a crucial problem in partitioning XML documents. Existing approaches need a pre-parse step to determine the partitions. In this paper, we propose a direct parallel method to solve this problem without pre-parsing. In the direct parallel method, we directly start the parallel parsing by finding the "light tower", which is a particular character with some exceptions, called clues. We handle the exceptions by watching the clues and reparsing the partition if it is required in the parsing stage. We also propose a non-synchronized splitter approach to the parallel XML querying using Xpath Expressions. In the non-synchronized splitter approach, we split an Xpath Expression into pieces to be executed by threads and we use a data structure, called the ancestor table, to help each thread handle its part of Xpath Expression independently without communications between threads. Our experiments show that our approach scales well from small sized files to huge sized files.
