Results 1 
5 of
5
Validating XML documents in the streaming model with external memory
 In ICDT
, 2012
"... We study the problem of validating XML documents of size N against general DTDs in the context of streaming algorithms. The starting point of this work is a wellknown space lower bound. There are XML documents and DTDs for which ppass streaming algorithms require Ω(N/p) space. We show that when al ..."
Abstract

Cited by 6 (2 self)
 Add to MetaCart
We study the problem of validating XML documents of size N against general DTDs in the context of streaming algorithms. The starting point of this work is a wellknown space lower bound. There are XML documents and DTDs for which ppass streaming algorithms require Ω(N/p) space. We show that when allowing access to external memory, there is a deterministic streaming algorithm that solves this problem with memory space O(log 2 N), a constant number of auxiliary read/write streams, and O(log N) total number of passes on the XML document and auxiliary streams. An important intermediate step of this algorithm is the computation of the FirstChildNextSibling (FCNS) encoding of the initial XML document in a streaming fashion. We study this problem independently, and we also provide memory efficient streaming algorithms for decoding an XML document given in its FCNS encoding. Furthermore, validating XML documents encoding binary trees in the usual streaming model without external memory can be done with sublinear memory. There is a onepass algorithm using O ( √ N log N) space, and a bidirectional twopass algorithm using O(log 2 N) space performing this task.
Machine Models for Query Processing
"... The massive data sets that have to be processed in many application areas are often far too large to fit completely into a computer’s internal memory. When evaluating queries on such large data sets, the resulting communication ..."
Abstract
 Add to MetaCart
The massive data sets that have to be processed in many application areas are often far too large to fit completely into a computer’s internal memory. When evaluating queries on such large data sets, the resulting communication
Strategy Machines and their Complexity (with addendum)
"... Abstract. We introduce a machine model for the execution of strategies in (regular) infinite games that refines the standard model of Mealy automata. This model of controllers is formalized in the terminological framework of Turing machines. We show how polynomially sized controllers can be found fo ..."
Abstract
 Add to MetaCart
Abstract. We introduce a machine model for the execution of strategies in (regular) infinite games that refines the standard model of Mealy automata. This model of controllers is formalized in the terminological framework of Turing machines. We show how polynomially sized controllers can be found for Muller and Streett games. We are able to distinguish aspects of executing strategies (“size”, “latency”, “space consumption”) that are not visible in Mealy automata. Also, lower bound results are obtained. 1
A Validating XML Documents in the Streaming Model with External
"... We study the problem of validating XML documents of size N against general DTDs in the context of streaming algorithms. The starting point of this work is a wellknown space lower bound. There are XML documents and DTDs for which ppass streaming algorithms require Ω(N/p) space. We show that when al ..."
Abstract
 Add to MetaCart
We study the problem of validating XML documents of size N against general DTDs in the context of streaming algorithms. The starting point of this work is a wellknown space lower bound. There are XML documents and DTDs for which ppass streaming algorithms require Ω(N/p) space. We show that when allowing access to external memory, there is a deterministic streaming algorithm that solves this problem with memory space O(log 2 N), a constant number of auxiliary read/write streams, and O(log N) total number of passes on the XML document and auxiliary streams. An important intermediate step of this algorithm is the computation of the FirstChildNextSibling (FCNS) encoding of the initial XML document in a streaming fashion. We study this problem independently, and we also provide memory efficient streaming algorithms for decoding an XML document given in its FCNS encoding. Furthermore, validating XML documents encoding binary trees against any DTD in the usual streaming model without external memory can be done with sublinear memory. There is a onepass algorithm using O ( √ N log N) space, and a bidirectional twopass algorithm using O(log 2 N) space which perform this task.
Input/Output Streaming Complexity of Reversal and Sorting ∗
"... This work revisits the study of streaming algorithms where both input and output are data streams. While streaming algorithms with multiple streams have been studied before, such as in the context of sorting, most assumed very nonrestrictive models and thus had weak lower bounds. We consider data st ..."
Abstract
 Add to MetaCart
This work revisits the study of streaming algorithms where both input and output are data streams. While streaming algorithms with multiple streams have been studied before, such as in the context of sorting, most assumed very nonrestrictive models and thus had weak lower bounds. We consider data streams with restricted access, such as readonly and writeonly streams, as opposed to readwrite streams. We also require streams to be processed in one direction only when multiple passes are allowed. Last, we forbid the use of any other external streams. Reversing a stream has been demonstrated to allow exponential speedup for several decision problems. Therefore, it naturally arises as the bottleneck problem of our model. We give several tight bounds for reversing the input stream depending on the model. We also study the problem of sorting, and improve previously known algorithms in terms of space used on the two streams. Partially supported by the French ANR Blanc project ANR12BS02005 (RDAM)