The Experts below are selected from a list of 803028 Experts worldwide ranked by ideXlab platform
Paul Hudak - One of the best experts on this subject based on the ideXlab platform.
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call by name assignment and the lambda calculus
Symposium on Principles of Programming Languages, 1993Co-Authors: Martin Odersky, Dan Rabin, Paul HudakAbstract:We define an extension of the call-by-name lambda calculus with additional constructs and reduction rules that represent mutable variables and assignments. The extended calculus has neither a concept of an explicit store nor a concept of Evaluation Order; nevertheless, we show that programs in the calculus can be implemented using a single-threaded store. We also show that the new calculus has the Church-Rosser property and that it is a conservative extension of classical lambda calculus with respect to operational equivalence; that is, all algebraic laws of the functional subset are preserved.
Dounia Zaidouni - One of the best experts on this subject based on the ideXlab platform.
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Cost-Optimal Execution of Boolean Query Trees with Shared Streams
2014Co-Authors: Henri Casanova, Lipyeow Lim, Yves Robert, Dounia ZaidouniAbstract:Abstract—The processing of queries expressed as trees of boolean operators applied to predicates on sensor data streams has several applications in mobile computing. Sensor data must be retrieved from the sensors, which incurs a cost, e.g., an energy expense that depletes the battery of a mobile query processing device. The objective is to determine the Order in which predicates should be evaluated so as to shortcut part of the query Evaluation and minimize the ex-pected cost. This problem has been studied assuming that each data stream occurs at a single predicate. In this work we remove this assumption since it does not necessarily hold in practice. Our main results are an optimal algorithm for single-level trees and a proof of NP-completeness for DNF trees. For DNF trees, however, we show that there is an optimal predicate Evaluation Order that corresponds to a depth-first traversal. This result provides inspiration for a class of heuristics. We show that one of these heuristics largely outperforms other sensible heuristics, includ-ing a heuristic proposed in previous work. I
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Cost-Optimal Execution of Boolean Query Trees with Shared Streams
2014Co-Authors: Henri Casanova, Lipyeow Lim, Yves Robert, Frédéric Vivien, Dounia ZaidouniAbstract:The processing of queries expressed as trees of boolean operators applied to predicates on sensor data streams has several applications in mobile computing. Sensor data must be retrieved from the sensors, which incurs a cost, e.g., an energy expense that depletes the battery of a mobile query processing device. The objective is to determine the Order in which predicates should be evaluated so as to shortcut part of the query Evaluation and minimize the expected cost. This problem has been studied assuming that each data stream occurs at a single predicate. In this work we remove this assumption since it does not necessarily hold for real-world queries. Our main results are an optimal algorithm for single-level trees and a proof of NP-completeness for DNF trees. For DNF trees, however, we show that there is an optimal predicate Evaluation Order that corresponds to a depth-first traversal. This result provides inspiration for a class of heuristics. We show that one of these heuristics largely outperforms other sensible heuristics, including a heuristic proposed in previous work.
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of Boolean Operators with Shared Streams
2014Co-Authors: Henri Casanova, Lipyeow Lim, Yves Robert, Frédéric Vivien, Dounia ZaidouniAbstract:Abstract: The processing of queries expressed as trees of boolean operators applied to predicates on sensor data streams has several applications in mobile computing. Sensor data must be retrieved from the sensors to a query processing device, such as a smartphone, over one or more network interfaces. Retrieving a data item incurs a cost, e.g., an energy expense that depletes the smartphone’s battery. Since the query tree contains boolean operators, part of the tree can be shortcircuited depending on the retrieved sensor data. An interesting problem is to determine the Order in which predicates should be evaluated so as to minimize the expected query processing cost. This problem has been studied in previous work assuming that each data stream occurs in a single predicate. In this work we remove this assumption since it does not necessarily hold for real-world queries. Our main results are an optimal algorithm for single-level trees and a proof of NP-completeness for DNF trees. For DNF trees, however, we show that there is an optimal predicate Evaluation Order that corresponds to a depth-first traversal. This result provides inspiration for a class of heuristics. We show that one of these heuristics largely outperforms other sensible heuristics, including the one heuristic proposed in previous work for our general version of the query processing problem. Key-words: sharing query processing, boolean operators, energy, scheduling, greedy algorithm, dat
Alan Mycroft - One of the best experts on this subject based on the ideXlab platform.
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extended call by push value reasoning about effectful programs and Evaluation Order
European Symposium on Programming, 2019Co-Authors: Dylan Mcdermott, Alan MycroftAbstract:Traditionally, reasoning about programs under varying Evaluation regimes (call-by-value, call-by-name etc.) was done at the meta-level, treating them as term rewriting systems. Levy’s call-by-push-value (CBPV) calculus provides a more powerful approach for reasoning, by treating CBPV terms as a common intermediate language which captures both call-by-value and call-by-name, and by allowing equational reasoning about changes to Evaluation Order between or within programs.
Martin Odersky - One of the best experts on this subject based on the ideXlab platform.
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call by name assignment and the lambda calculus
Symposium on Principles of Programming Languages, 1993Co-Authors: Martin Odersky, Dan Rabin, Paul HudakAbstract:We define an extension of the call-by-name lambda calculus with additional constructs and reduction rules that represent mutable variables and assignments. The extended calculus has neither a concept of an explicit store nor a concept of Evaluation Order; nevertheless, we show that programs in the calculus can be implemented using a single-threaded store. We also show that the new calculus has the Church-Rosser property and that it is a conservative extension of classical lambda calculus with respect to operational equivalence; that is, all algebraic laws of the functional subset are preserved.
Henri Casanova - One of the best experts on this subject based on the ideXlab platform.
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Cost-Optimal Execution of Boolean Query Trees with Shared Streams
2014Co-Authors: Henri Casanova, Lipyeow Lim, Yves Robert, Dounia ZaidouniAbstract:Abstract—The processing of queries expressed as trees of boolean operators applied to predicates on sensor data streams has several applications in mobile computing. Sensor data must be retrieved from the sensors, which incurs a cost, e.g., an energy expense that depletes the battery of a mobile query processing device. The objective is to determine the Order in which predicates should be evaluated so as to shortcut part of the query Evaluation and minimize the ex-pected cost. This problem has been studied assuming that each data stream occurs at a single predicate. In this work we remove this assumption since it does not necessarily hold in practice. Our main results are an optimal algorithm for single-level trees and a proof of NP-completeness for DNF trees. For DNF trees, however, we show that there is an optimal predicate Evaluation Order that corresponds to a depth-first traversal. This result provides inspiration for a class of heuristics. We show that one of these heuristics largely outperforms other sensible heuristics, includ-ing a heuristic proposed in previous work. I
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Cost-Optimal Execution of Boolean Query Trees with Shared Streams
2014Co-Authors: Henri Casanova, Lipyeow Lim, Yves Robert, Frédéric Vivien, Dounia ZaidouniAbstract:The processing of queries expressed as trees of boolean operators applied to predicates on sensor data streams has several applications in mobile computing. Sensor data must be retrieved from the sensors, which incurs a cost, e.g., an energy expense that depletes the battery of a mobile query processing device. The objective is to determine the Order in which predicates should be evaluated so as to shortcut part of the query Evaluation and minimize the expected cost. This problem has been studied assuming that each data stream occurs at a single predicate. In this work we remove this assumption since it does not necessarily hold for real-world queries. Our main results are an optimal algorithm for single-level trees and a proof of NP-completeness for DNF trees. For DNF trees, however, we show that there is an optimal predicate Evaluation Order that corresponds to a depth-first traversal. This result provides inspiration for a class of heuristics. We show that one of these heuristics largely outperforms other sensible heuristics, including a heuristic proposed in previous work.
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of Boolean Operators with Shared Streams
2014Co-Authors: Henri Casanova, Lipyeow Lim, Yves Robert, Frédéric Vivien, Dounia ZaidouniAbstract:Abstract: The processing of queries expressed as trees of boolean operators applied to predicates on sensor data streams has several applications in mobile computing. Sensor data must be retrieved from the sensors to a query processing device, such as a smartphone, over one or more network interfaces. Retrieving a data item incurs a cost, e.g., an energy expense that depletes the smartphone’s battery. Since the query tree contains boolean operators, part of the tree can be shortcircuited depending on the retrieved sensor data. An interesting problem is to determine the Order in which predicates should be evaluated so as to minimize the expected query processing cost. This problem has been studied in previous work assuming that each data stream occurs in a single predicate. In this work we remove this assumption since it does not necessarily hold for real-world queries. Our main results are an optimal algorithm for single-level trees and a proof of NP-completeness for DNF trees. For DNF trees, however, we show that there is an optimal predicate Evaluation Order that corresponds to a depth-first traversal. This result provides inspiration for a class of heuristics. We show that one of these heuristics largely outperforms other sensible heuristics, including the one heuristic proposed in previous work for our general version of the query processing problem. Key-words: sharing query processing, boolean operators, energy, scheduling, greedy algorithm, dat
