The Experts below are selected from a list of 786 Experts worldwide ranked by ideXlab platform

Mitchell Wand - One of the best experts on this subject based on the ideXlab platform.

  • Type inference for record Concatenation and multiple inheritance
    Information and Computation, 1991
    Co-Authors: Mitchell Wand
    Abstract:

    Abstract We show that the type inference problem for a lambda calculus with records, including a record Concatenation Operator, is decidable. We show that this calculus does not have principal types, but does have finite complete sets of types: that is, for any term M in the calculus, there exists an effectively generable finite set of type schemes such that every typing for M is an instance of one of the schemes in the set. We show how a simple model of object-oriented programming, including hidden instance variables and multiple inheritance, may be coded in this calculus. We conclude that type inference is decidable for object-oriented programs, even with multiple inheritance and classes as first-class values.

  • LICS - Type inference for record Concatenation and multiple inheritance
    [1989] Proceedings. Fourth Annual Symposium on Logic in Computer Science, 1
    Co-Authors: Mitchell Wand
    Abstract:

    The author shows that the type inference problem for a lambda calculus with records, including a record Concatenation Operator, is decidable. He shows that this calculus does not have principal types but does have finite complete sets of type, that is, for any term M in the calculus, there exists an effectively generable finite set of type schemes such that every typing for M is an instance of one of the schemes in the set. The author shows how a simple model of object-oriented programming, including hidden instance variables and multiple inheritance, may be coded in this calculus. The author concludes that type inference is decidable for object-oriented programs, even with multiple inheritance and classes as first-class values. >

Tian Zhao - One of the best experts on this subject based on the ideXlab platform.

  • Type inference for record Concatenation and subtyping
    Information and Computation, 2004
    Co-Authors: Jens Palsberg, Tian Zhao
    Abstract:

    Record Concatenation, multiple inheritance, and multiple-object cloning are closely related and part of various language designs. For example, in Cardelli's untyped Obliq language, a new object can be constructed from several existing objects by cloning followed by Concatenation; an error is given in case of field name conflicts. Type systems for record Concatenation have been studied by Wand, Harper and Pierce, Remy, and others; and type inference for the combination of record Concatenation and subtyping has been studied by Sulzmann and by Pottier. In this paper we present a type inference algorithm for record Concatenation, subtyping, and recursive types. Our example language is the Abadi-Cardelli object calculus extended with a Concatenation Operator. Our algorithm enables type checking of Obliq programs without changing the programs at all. We prove that the type inference problem is NP-complete.

  • LICS - Efficient type inference for record Concatenation and subtyping
    Proceedings 17th Annual IEEE Symposium on Logic in Computer Science, 1
    Co-Authors: Jens Palsberg, Tian Zhao
    Abstract:

    Record Concatenation, multiple inheritance, and multiple-object cloning are closely related and part of various language designs. For example, in Cardelli's untyped Obliq language, a new object can be constructed from several existing objects by cloning followed by Concatenation; an error is given in case of field name conflicts. Type systems for record Concatenation have been studied by M. Wand (1991), R. Harper and B. Pierce (1991), D. Remy (1992), and others; and type inference for the combination of record Concatenation and subtyping has been studied by M. Sulzmann (1997) and by F. Pottier (2000). In this paper we present the first polynomial-time type inference algorithm for record Concatenation, subtyping, and recursive types. Our example language is the Abadi-Cardelli object calculus extended with a Concatenation Operator The type inference algorithm runs in O(n/sup 5/) time where n is the size of the program. Our algorithm enables efficient type checking of Obliq programs without changing the programs at all.

Jens Palsberg - One of the best experts on this subject based on the ideXlab platform.

  • Type inference for record Concatenation and subtyping
    Information and Computation, 2004
    Co-Authors: Jens Palsberg, Tian Zhao
    Abstract:

    Record Concatenation, multiple inheritance, and multiple-object cloning are closely related and part of various language designs. For example, in Cardelli's untyped Obliq language, a new object can be constructed from several existing objects by cloning followed by Concatenation; an error is given in case of field name conflicts. Type systems for record Concatenation have been studied by Wand, Harper and Pierce, Remy, and others; and type inference for the combination of record Concatenation and subtyping has been studied by Sulzmann and by Pottier. In this paper we present a type inference algorithm for record Concatenation, subtyping, and recursive types. Our example language is the Abadi-Cardelli object calculus extended with a Concatenation Operator. Our algorithm enables type checking of Obliq programs without changing the programs at all. We prove that the type inference problem is NP-complete.

  • LICS - Efficient type inference for record Concatenation and subtyping
    Proceedings 17th Annual IEEE Symposium on Logic in Computer Science, 1
    Co-Authors: Jens Palsberg, Tian Zhao
    Abstract:

    Record Concatenation, multiple inheritance, and multiple-object cloning are closely related and part of various language designs. For example, in Cardelli's untyped Obliq language, a new object can be constructed from several existing objects by cloning followed by Concatenation; an error is given in case of field name conflicts. Type systems for record Concatenation have been studied by M. Wand (1991), R. Harper and B. Pierce (1991), D. Remy (1992), and others; and type inference for the combination of record Concatenation and subtyping has been studied by M. Sulzmann (1997) and by F. Pottier (2000). In this paper we present the first polynomial-time type inference algorithm for record Concatenation, subtyping, and recursive types. Our example language is the Abadi-Cardelli object calculus extended with a Concatenation Operator The type inference algorithm runs in O(n/sup 5/) time where n is the size of the program. Our algorithm enables efficient type checking of Obliq programs without changing the programs at all.

Sunil Aryal - One of the best experts on this subject based on the ideXlab platform.

  • HDF: Hybrid Deep Features for Scene Image Representation
    2020 International Joint Conference on Neural Networks (IJCNN), 2020
    Co-Authors: Chiranjibi Sitaula, Yong Xiang, Anish Basnet, Sunil Aryal
    Abstract:

    Nowadays it is prevalent to take features extracted from pre-trained deep learning models as image representations which have achieved promising classification performance. Existing methods usually consider either object-based features or scene-based features only. However, both types of features are important for complex images like scene images, as they can complement each other. In this paper, we propose a novel type of features -- hybrid deep features, for scene images. Specifically, we exploit both object-based and scene-based features at two levels: part image level (i.e., parts of an image) and whole image level (i.e., a whole image), which produces a total number of four types of deep features. Regarding the part image level, we also propose two new slicing techniques to extract part based features. Finally, we aggregate these four types of deep features via the Concatenation Operator. We demonstrate the effectiveness of our hybrid deep features on three commonly used scene datasets (MIT-67, Scene-15, and Event-8), in terms of the scene image classification task. Extensive comparisons show that our introduced features can produce state-of-the-art classification accuracies which are more consistent and stable than the results of existing features across all datasets.

Hugo Herbelin - One of the best experts on this subject based on the ideXlab platform.

  • CSL - A Lambda-Calculus Structure Isomorphic to Gentzen-Style Sequent Calculus Structure
    Computer Science Logic, 1995
    Co-Authors: Hugo Herbelin
    Abstract:

    We consider a λ-calculus for which applicative terms have no longer the form (...((u u1) u2)... un) but the form (u [u1;...;un]), for which [u1;...;un] is a list of terms. While the structure of the usual λ-calculus is isomorphic to the structure of natural deduction, this new structure is isomorphic to the structure of Gentzen-style sequent calculus. To express the basis of the isomorphism, we consider intuitionistic logic with the implication as sole connective. However we do not consider Gentzen's calculus LJ, but a calculus LJT which leads to restrict the notion of cut-free proofs in LJ. We need also to explicitly consider, in a simply typed version of this λ-calculus, a substitution Operator and a list Concatenation Operator. By this way, each elementary step of cutelimination exactly matches with a β-reduction, a substitution propagation step or a Concatenation computation step.

  • a lambda calculus structure isomorphic to gentzen style sequent calculus structure
    Computer Science Logic, 1994
    Co-Authors: Hugo Herbelin
    Abstract:

    We consider a λ-calculus for which applicative terms have no longer the form (...((u u1) u2)... un) but the form (u [u1;...;un]), for which [u1;...;un] is a list of terms. While the structure of the usual λ-calculus is isomorphic to the structure of natural deduction, this new structure is isomorphic to the structure of Gentzen-style sequent calculus. To express the basis of the isomorphism, we consider intuitionistic logic with the implication as sole connective. However we do not consider Gentzen's calculus LJ, but a calculus LJT which leads to restrict the notion of cut-free proofs in LJ. We need also to explicitly consider, in a simply typed version of this λ-calculus, a substitution Operator and a list Concatenation Operator. By this way, each elementary step of cutelimination exactly matches with a β-reduction, a substitution propagation step or a Concatenation computation step.

  • A Lambda-calculus Structure Isomorphic to Gentzen-style Sequent Calculus Structure
    1994
    Co-Authors: Hugo Herbelin
    Abstract:

    We consider a lambda-calculus for which applicative terms have no longer the form (...((u u_1) u_2) ... u_n) but the form (u [u_1 ; ... ; u_n]), for which [u_1 ; ... ; u_n] is a list of terms. While the structure of the usual lambda-calculus is isomorphic to the structure of natural deduction, this new structure is isomorphic to the structure of Gentzen-style sequent calculus. To express the basis of the isomorphism, we consider intuitionistic logic with the implication as sole connective. However we do not consider Gentzen's calculus LJ, but a calculus LJT which leads to restrict the notion of cut-free proofs in LJ. We need also to explicitly consider, in a simply typed version of this lambda-calculus, a substitution Operator and a list Concatenation Operator. By this way, each elementary step of cut-elimination exactly matches with a beta-reduction, a substitution propagation step or a Concatenation computation step. Though it is possible to extend the isomorphism to classical logic and to other connectives, we do not treat of it in this paper.