Nowadays specialized distributed services and sig-nificant amounts of computing resources are used for solving tasks in Big Data processing and analysis. Cloud environments allow people to create virtual clusters with...
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In this paper we propose a new DataGuide-based locking protocol for isolation of concurrent XML transactions. The protocol adopts DataGuide structure for locking purposes. We extend the multigranularity locking protoc...
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In this paper we propose a new DataGuide-based locking protocol for isolation of concurrent XML transactions. The protocol adopts DataGuide structure for locking purposes. We extend the multigranularity locking protocol by adding node and logical locks on DataGuide. This allows to enhance concurrency of XML-specific transactions, thereby increasing the overall system performance.
Today XML has become the most important data exchange technique on the World Wide Web. As a consequence the interest in concurrent XML processing has greatly increased. In this paper we propose a new XPath-based DataG...
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Nowadays, XML has emerged as the standard technique for storing and exchanging semistructured data. The retrieval and update of XML documents in the multi-user databases requires isolation of con- current transactions...
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ISBN:
(纸本)8854801224
Nowadays, XML has emerged as the standard technique for storing and exchanging semistructured data. The retrieval and update of XML documents in the multi-user databases requires isolation of con- current transactions from each other. This paper presents a novel scheduler to synchronize concurrent access to XML documents through XPath and update operations. Our method extends the conventional multigranularity locking scheme and adjusts it to the hierarchical nature of XML. We propose two kinds of locks on DataGuide structure: node and tree locks. Besides, we introduce logical locks on the DataGuide's subtrees to prevent phantoms appearance. A proposed scheduler takes into consideration the semantics of XPath and update operations which significantly increases the degree of concurrency. The proposed method is primarily being implemented in the native XML DBMS Sedna, but it is applicable to any existing XML DBMS that supports the DataGuide structure.
Distinguishing sequences are used in model based mutation testing in order to distinguish the specification from its mutants that usually represent critical implementation faults. In this paper, we consider distinguis...
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The problem of finding a maximal dense subgraph of a power-law random graph G(n, α) is considered for every value of density c ε (0, 1) and for every a ε (0,+∞). It is shown that in case α p(n1-α/2), in case α ...
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Industrial static analyzers are able to detect only several narrow classes of algorithmic errors, for example actual arguments order swapped with formal parameters, forgotten renaming of variable after copy-paste. How...
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The paper investigates the implementation of virtual networks on the SDN data plane, modeled by a graph of physical connections between network nodes. A virtual network is defined as a set of ordered host pairs (sende...
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Most of the state-of-the-art verifiers do not scale well on complicated software. Concurrency benchmarks from SV-COMP based on Linux device drivers cause significant difficulties for any software model checker tool. W...
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