The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
Michael Kifer - One of the best experts on this subject based on the ideXlab platform.
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Inheritance in rule based frame systems semantics and inference
Journal on Data Semantics, 2006Co-Authors: Guizhen Yang, Michael KiferAbstract:Knowledge representation languages that combine rules with object-oriented features akin to frame systems have recently attracted a lot of research interest, and F-logic is widely seen as a basis to achieve this integration. In this paper we extend the original F-logic formalism with an array of salient features that are essential for representing and reasoning with commonsense knowledge. In particular, we extend the syntax and semantics of F-logic to incorporate nonmonotonic Multiple Inheritance of class and instance methods in the presentence of class hierarchies defined via rules. The new semantics is completely model-theoretic and is free of the defects that caused the original F-logic to produce unintuitive results due to the unusual interaction between default Inheritance and inference via rules. Moreover, we provide a computational framework for the new F-logic semantics which can be implemented by inference engines using either forward or backward chaining mechanisms.
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a theory of nonmonotonic Inheritance based on annotated logic
Artificial Intelligence, 1993Co-Authors: Krishnaprasad Thirunarayan, Michael KiferAbstract:Abstract We propose a logical language for representing networks with nonmonotonic Multiple Inheritance. The language is based on a variant of annotated logic studied in [5, 6, 17–21]. The use of annotated logic provides a rich setting that allows to disambiguate networks whose topology does not provide enough information to decide how properties are to be inherited. The proposed formalism handles Inheritance via strict as well as defeasible links. We provide a formal account of the language, describe its semantics, and show how a unique intended model can be associated with every Inheritance specification written in the language. Finally, we present an algorithm that correctly propagates inherited properties according to the given semantics. The algorithm is also complete in the sense that it computes the set of all properties that must be inherited by any given individual object, and then terminates.
Dapena, Elena Porta - One of the best experts on this subject based on the ideXlab platform.
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Mutations in Either TUBB or MAPRE2 Cause Circumferential Skin Creases Kunze Type
American Society of Human Genetics, 2015Co-Authors: Isrie Mala, Breuss Martin, Tian Guoling, Hansen, Andi Harley, Cristofoli Francesca, Morandell Jasmin, Kupchinsky, Zachari A, Sifrim Alejandro, Rodriguez-rodriguez, Celia Maria, Dapena, Elena PortaAbstract:Circumferential skin creases Kunze type (CSC-KT) is a specific congenital entity with an unknown genetic cause. The disease phenotype comprises characteristic circumferential skin creases accompanied by intellectual disability, a cleft palate, short stature, and dysmorphic features. Here, we report that mutations in either MAPRE2 or TUBB underlie the genetic origin of this syndrome. MAPRE2 encodes a member of the microtubule end-binding family of proteins that bind to the guanosine triphosphate cap at growing microtubule plus ends, and TUBB encodes a β-tubulin isotype that is expressed abundantly in the developing brain. Functional analyses of the TUBB mutants show Multiple defects in the chaperone-dependent tubulin heterodimer folding and assembly pathway that leads to a compromised yield of native heterodimers. The TUBB mutations also have an impact on microtubule dynamics. For MAPRE2, we show that the mutations result in enhanced MAPRE2 binding to microtubules, implying an increased dwell time at microtubule plus ends. Further, in vivo analysis of MAPRE2 mutations in a zebrafish model of craniofacial development shows that the variants most likely perturb the patterning of branchial arches, either through excessive activity (under a recessive paradigm) or through haploinsufficiency (dominant de novo paradigm). Taken together, our data add CSC-KT to the growing list of tubulinopathies and highlight how Multiple Inheritance paradigms can affect dosage-sensitive biological systems so as to result in the same clinical defect.status: publishe
Elena Porta Dapena - One of the best experts on this subject based on the ideXlab platform.
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mutations in either tubb or mapre2 cause circumferential skin creases kunze type
American Journal of Human Genetics, 2015Co-Authors: Mala Isrie, Martin Breuss, Guoling Tian, Andi H Hansen, Francesca Cristofoli, Jasmin Morandell, Zachari A Kupchinsky, Alejandro Sifrim, Celia Maria Rodriguezrodriguez, Elena Porta DapenaAbstract:Circumferential skin creases Kunze type (CSC-KT) is a specific congenital entity with an unknown genetic cause. The disease phenotype comprises characteristic circumferential skin creases accompanied by intellectual disability, a cleft palate, short stature, and dysmorphic features. Here, we report that mutations in either MAPRE2 or TUBB underlie the genetic origin of this syndrome. MAPRE2 encodes a member of the microtubule end-binding family of proteins that bind to the guanosine triphosphate cap at growing microtubule plus ends, and TUBB encodes a β-tubulin isotype that is expressed abundantly in the developing brain. Functional analyses of the TUBB mutants show Multiple defects in the chaperone-dependent tubulin heterodimer folding and assembly pathway that leads to a compromised yield of native heterodimers. The TUBB mutations also have an impact on microtubule dynamics. For MAPRE2, we show that the mutations result in enhanced MAPRE2 binding to microtubules, implying an increased dwell time at microtubule plus ends. Further, in vivo analysis of MAPRE2 mutations in a zebrafish model of craniofacial development shows that the variants most likely perturb the patterning of branchial arches, either through excessive activity (under a recessive paradigm) or through haploinsufficiency (dominant de novo paradigm). Taken together, our data add CSC-KT to the growing list of tubulinopathies and highlight how Multiple Inheritance paradigms can affect dosage-sensitive biological systems so as to result in the same clinical defect.
Olaf Owe - One of the best experts on this subject based on the ideXlab platform.
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incremental reasoning with lazy behavioral subtyping for Multiple Inheritance
Science of Computer Programming, 2011Co-Authors: Johan Dovland, Einar Broch Johnsen, Olaf Owe, Martin SteffenAbstract:Object-orientation supports code reuse and incremental programming. Multiple Inheritance increases the possibilities for code reuse, but complicates the binding of method calls and thereby program analysis. Behavioral subtyping allows program analysis under an open world assumption; i.e., under the assumption that class hierarchies are extensible. However, method redefinition is severely restricted by behavioral subtyping, and Multiple Inheritance may lead to conflicting restrictions from independently designed superclasses. This paper presents a more liberal approach to incremental reasoning for Multiple Inheritance under an open world assumption. The approach, based on lazy behavioral subtyping, is well-suited for Multiple Inheritance, as it incrementally imposes context-dependent behavioral constraints on new subclasses. We first present the approach for a simple language and show how incremental reasoning can be combined with flexible code reuse. Then this language is extended with a hierarchy of interface types which is independent of the class hierarchy. In this setting, flexible code reuse can be combined with modular reasoning about external calls in the sense that each class is analyzed only once. We formalize the approach as a calculus and show soundness for both languages.
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incremental reasoning for Multiple Inheritance
Integrated Formal Methods, 2009Co-Authors: Johan Dovland, Einar Broch Johnsen, Olaf Owe, Martin SteffenAbstract:Object-orientation supports code reuse and incremental programming. Multiple Inheritance increases the power of code reuse, but complicates the binding of method calls and thereby program analysis. Behavioral subtyping allows program analysis under an open world assumption ; i.e., under the assumption that class hierarchies are extensible. However, method redefinition is severely restricted by behavioral subtyping, and Multiple Inheritance often leads to conflicting restrictions from independently designed superclasses. This paper presents an approach to incremental reasoning for Multiple Inheritance under an open world assumption. The approach, based on a notion of lazy behavioral subtyping , is less restrictive than behavioral subtyping and fits well with Multiple Inheritance, as it incrementally imposes context-dependent behavioral constraints on new subclasses. We formalize the approach as a calculus, for which we show soundness.
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a dynamic binding strategy for Multiple Inheritance and asynchronously communicating objects
Formal Methods, 2004Co-Authors: Einar Broch Johnsen, Olaf OweAbstract:This paper considers an integration of asynchronous communication, virtual binding, and Multiple Inheritance. Object orientation is the leading paradigm for concurrent and distributed systems, but the tightly synchronized RPC communication model seems unsatisfactory in the distributed setting. Asynchronous messages are better suited, but lack the structure and discipline of traditional object-oriented methods. The integration of messages in the object-oriented paradigm is unsettled, especially with respect to Inheritance and redefinition. Asynchronous method calls have been proposed in the Creol language, reducing the cost of waiting for replies in the distributed environment while avoiding low-level synchronization constructs such as explicit signaling. A lack of reply to a method call need not lead to deadlock in the calling object. Creol has an operational semantics defined in rewriting logic. This paper considers a formal operational model of Multiple Inheritance, virtual binding, and asynchronous communication between concurrent objects, extending the semantics of Creol.
Guy L Steele - One of the best experts on this subject based on the ideXlab platform.
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fine grained function visibility for Multiple dispatch with Multiple Inheritance
Asian Symposium on Programming Languages and Systems, 2013Co-Authors: Jieung Kim, Sukyoung Ryu, Victor Luchangco, Guy L SteeleAbstract:Object-oriented languages with Multiple dispatch and Multiple Inheritance provide rich expressiveness but statically and modularly checking programs in such languages to guarantee that no ambiguous calls can occur at run time has been a difficult problem. We present a core calculus for Fortress, which provides various language features-notably functional methods and components- and solves the problem. Functional methods are declared within traits and may be inherited but are invoked by ordinary function calls, and therefore compete in overloading resolution with ordinary function declarations. A novel component system governs "visibility" of types and functions, and allows fine-grained control over the import of overloaded functions. We formally define the type system of Fortress with a set of static rules to guarantee no ambiguous calls at run time, and mechanize the calculus and its type safety proof in Coq.
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type checking modular Multiple dispatch with parametric polymorphism and Multiple Inheritance
Conference on Object-Oriented Programming Systems Languages and Applications, 2011Co-Authors: Eric Allen, Sukyoung Ryu, Victor Luchangco, Justin Hilburn, Scott Kilpatrick, David R Chase, Guy L SteeleAbstract:In previous work, we presented rules for defining overloaded functions that ensure type safety under symmetric Multiple dispatch in an object-oriented language with Multiple Inheritance, and we showed how to check these rules without requiring the entire type hierarchy to be known, thus supporting modularity and extensibility. In this work, we extend these rules to a language that supports parametric polymorphism on both classes and functions.In a Multiple-Inheritance language in which any type may be extended by types in other modules, some overloaded functions that might seem valid are correctly rejected by our rules. We explain how these functions can be permitted in a language that additionally supports an exclusion relation among types, allowing programmers to declare "nominal exclusions" and also implicitly imposing exclusion among different instances of each polymorphic type. We give rules for computing the exclusion relation, deriving many type exclusions from declared and implicit ones.We also show how to check our rules for ensuring the safety of overloaded functions. In particular, we reduce the problem of handling parametric polymorphism to one of determining subtyping relationships among universal and existential types. Our system has been implemented as part of the open-source Fortress compiler.
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modular Multiple dispatch with Multiple Inheritance
ACM Symposium on Applied Computing, 2007Co-Authors: Eric Allen, Sukyoung Ryu, Joe Hallett, Victor Luchangco, Guy L SteeleAbstract:Overloaded functions and methods with Multiple dispatch are useful for extending the functionality of existing classes in an object-oriented language. However, such functions introduce the possibility of ambiguous calls that cannot be resolved at run time, and modular static checking that such ambiguity does not exist has proved elusive in the presence of Multiple implementation Inheritance. We present a core language for defining overloaded functions and methods that supports Multiple dispatch and Multiple Inheritance, together with a set of restrictions on these definitions that can be statically and modularly checked. We have proved that these restrictions guarantee that no undefined nor ambiguous calls occur at run time, while still permitting various kinds of overloading.
