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43
Interprocedural Slicing Using Dependence Graphs
 ACM TRANSACTIONS ON PROGRAMMING LANGUAGES AND SYSTEMS
, 1990
"... ... This paper concerns the problem of interprocedural slicinggenerating a slice of an entire program, where the slice crosses the boundaries of procedure calls. To solve this problem, we introduce a new kind of graph to represent programs, called a system dependence graph, which extends previou ..."
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Cited by 696 (78 self)
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... This paper concerns the problem of interprocedural slicinggenerating a slice of an entire program, where the slice crosses the boundaries of procedure calls. To solve this problem, we introduce a new kind of graph to represent programs, called a system dependence graph, which extends previous dependence representations to incorporate collections of procedures (with procedure calls) rather than just monolithic programs. Our main result is an algorithm for interprocedural slicing that uses the new representation. (It should be noted that our work concerns a somewhat restricted kind of slice: Rather than permitting a program to be sliced with respect to program point p and an arbitrary variable, a slice must be taken with respect to a variable that is defined or used at p.) The chief
Computing on Data Streams
, 1998
"... In this paper we study the space requirement of algorithms that make only one (or a small number of) pass(es) over the input data. We study such algorithms under a model of data streams that we introduce here. We give a number of upper and lower bounds for problems stemming from queryprocessing, ..."
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Cited by 156 (3 self)
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In this paper we study the space requirement of algorithms that make only one (or a small number of) pass(es) over the input data. We study such algorithms under a model of data streams that we introduce here. We give a number of upper and lower bounds for problems stemming from queryprocessing, invoking in the process tools from the area of communication complexity.
Regular Path Queries with Constraints
 SYMPOSIUM ON PRINCIPLES OF DATABASE SYSTEMS
, 1997
"... The evaluation of path expression queries on semistructured data in a distributed asynchronous environment is considered. The focus is on the use of local information expressed in the form of path constraints in the optimization of path expression queries. In particular, decidability and complexity ..."
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Cited by 147 (6 self)
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The evaluation of path expression queries on semistructured data in a distributed asynchronous environment is considered. The focus is on the use of local information expressed in the form of path constraints in the optimization of path expression queries. In particular, decidability and complexity results on the implication problem for path constraints are established.
Analysis of Recursive State Machines
 In Proceedings of CAV 2001
, 2001
"... . Recursive state machines (RSMs) enhance the power of ordinary state machines by allowing vertices to correspond either to ordinary states or to potentially recursive invocations of other state machines. RSMs can model the control flow in sequential imperative programs containing recursive proc ..."
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Cited by 111 (21 self)
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. Recursive state machines (RSMs) enhance the power of ordinary state machines by allowing vertices to correspond either to ordinary states or to potentially recursive invocations of other state machines. RSMs can model the control flow in sequential imperative programs containing recursive procedure calls. They can be viewed as a visual notation extending Statechartslike hierarchical state machines, where concurrency is disallowed but recursion is allowed. They are also related to various models of pushdown systems studied in the verification and program analysis communities. After introducing RSMs, we focus on whether statespace analysis can be performed efficiently for RSMs. We consider the two central problems for algorithmic analysis and model checking, namely, reachability (is a target state reachable from initial states) and cycle detection (is there a reachable cycle containing an accepting state). We show that both these problems can be solved in time O(n` 2 ) and space O(n`), where n is the size of the recursive machine and ` is the maximum, over all component state machines, of the minimum of the number of entries and the number of exits of each component. We also study the precise relationship between RSMs and closely related models. 1
Finding Regular Simple Paths In Graph Databases
, 1989
"... We consider the following problem: given a labelled directed graph G and a regular expression R, find all pairs of nodes connected by a simple path such that the concatenation of the labels along the path satisfies R. The problem is motivated by the observation that many recursive queries in relatio ..."
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Cited by 109 (5 self)
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We consider the following problem: given a labelled directed graph G and a regular expression R, find all pairs of nodes connected by a simple path such that the concatenation of the labels along the path satisfies R. The problem is motivated by the observation that many recursive queries in relational databases can be expressed in this form, and by the implementation of a query language, G+ , based on this observation. We show that the problem is in general intractable, but present an algorithm than runs in polynomial time in the size of the graph when the regular expression and the graph are free of conflicts. We also present a class of languages whose expressions can always be evaluated in time polynomial in the size of both the graph and the expression, and characterize syntactically the expressions for such languages. Key words. Labelled directed graphs, NPcompleteness, polynomialtime algorithms, regular expressions, simple paths AMS(MOS) subject classifications. 68P, 6...
Algorithmics and Applications of Tree and Graph Searching
 In Symposium on Principles of Database Systems
, 2002
"... Modern search engines answer keywordbased queries extremely efficiently. The impressive speed is due to clever inverted index structures, caching, a domainindependent knowledge of strings, and thousands of machines. Several research efforts have attempted to generalize keyword search to keytree an ..."
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Cited by 109 (8 self)
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Modern search engines answer keywordbased queries extremely efficiently. The impressive speed is due to clever inverted index structures, caching, a domainindependent knowledge of strings, and thousands of machines. Several research efforts have attempted to generalize keyword search to keytree and keygraph searching, because trees and graphs have many applications in nextgeneration database systems. This paper surveys both algorithms and applications, giving some emphasis to our own work.
Survey of graph database models
, 2001
"... Graph database models can be characterized as those where data structures for the schema and instances are modeled as graphs or generalizations of them, and data manipulation is expressed by graphoriented operations and type constructors. These models flourished in the eighties and early nineties i ..."
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Cited by 54 (7 self)
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Graph database models can be characterized as those where data structures for the schema and instances are modeled as graphs or generalizations of them, and data manipulation is expressed by graphoriented operations and type constructors. These models flourished in the eighties and early nineties in parallel to object oriented models and their influence gradually faded with the emergence of other database models, particularly the geographical, spatial, semistructured and XML. Recently, the need to manage information with inherent graphlike nature has brought back the relevance of the area. In fact, a whole new wave of applications for graph databases emerged with the development of huge networks (e.g. Web, geographical systems, transportation, telephones), and families of networks generated due to the automation of the process of data gathering (e.g. social and biological networks). The main objective of this survey is to present in a single place the work that has been done in the area of graph database modeling, concentrating in data structures, query languages and integrity constraints.
TypeBased Flow Analysis: From Polymorphic Subtyping to CFLReachability.
 In Proceedings of the 28th Annual ACM SIGPLANSIGACT Symposium on Principles of Programming Languages
, 2001
"... We present a novel approach to scalable implementation of typebased flow analysis with polymorphic subtyping. Using a new presentation of polymorphic subtyping with instantiation constraints, we are able to apply contextfree language (CFL) reachability techniques to typebased flow analysis. We de ..."
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Cited by 52 (1 self)
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We present a novel approach to scalable implementation of typebased flow analysis with polymorphic subtyping. Using a new presentation of polymorphic subtyping with instantiation constraints, we are able to apply contextfree language (CFL) reachability techniques to typebased flow analysis. We develop a CFLbased algorithm for computing flow information in time O(n 3 ), where n is the size of the typed program. The algorithm substantially improves upon the best previously known algorithm for flow analysis based on polymorphic subtyping with complexity O(n 8 ). Our technique also yields the first demanddriven algorithm for polymorphic subtypebased flowcomputation. It works directly on higherorder programs with structured data of finite type (unbounded data structures are incorporated via finite approximations), supports contextsensitive, global flow summarization and includes polymorphic recursion.
Querying rdf data from a graph database perspective
 In Proceedings of the Second European Semantic Web Conference
, 2005
"... Abstract. This paper studies the RDF model from a database perspective. From this point of view it is compared with other database models, particularly with graph database models, which are very close in motivations and use cases to RDF. We concentrate on query languages, analyze current RDF trends, ..."
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Cited by 48 (6 self)
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Abstract. This paper studies the RDF model from a database perspective. From this point of view it is compared with other database models, particularly with graph database models, which are very close in motivations and use cases to RDF. We concentrate on query languages, analyze current RDF trends, and propose the incorporation to RDF query languages of primitives which are not present today, based on the experience and techniques of graph database research. 1
Timing Verification by Successive Approximation
 INFORMATION AND COMPUTATION
, 1995
"... We present an algorithm for verifying that a model M with timing constraints satisfies a given temporal property T . The model M is given as a parallel composition of !automata P i , where each automaton P i is constrained by bounds on delays. The property T is given as an !automaton as well, and ..."
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Cited by 44 (11 self)
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We present an algorithm for verifying that a model M with timing constraints satisfies a given temporal property T . The model M is given as a parallel composition of !automata P i , where each automaton P i is constrained by bounds on delays. The property T is given as an !automaton as well, and the verification problem is posed as a language inclusion question L(M ) ` L(T ). In constructing the composition M of the constrained automata P i , one needs to rule out the behaviors that are inconsistent with the delay bounds, and this step is (provably) computationally expensive. We propose an iterative solution which involves generating successive approximations M j to M , with containment L(M ) ` L(M j ) and monotone convergence L(M j ) ! L(M ) within a bounded number of steps. As the succession progresses, the approximations M j become more complex. At any step of the iteration one may get a proof or a counterexample to the original language inclusion question. The described algori...