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68
Regular Types for Active Objects
, 1993
"... Previous work on typetheoretic foundations for objectoriented programming languages has mostly focused on applying or extending functional type theory to functional "objects." This approach, while benefiting from a vast body of existing literature, has the disadvantage of dealing with state change ..."
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Cited by 187 (5 self)
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Previous work on typetheoretic foundations for objectoriented programming languages has mostly focused on applying or extending functional type theory to functional "objects." This approach, while benefiting from a vast body of existing literature, has the disadvantage of dealing with state change either in a roundabout way or not at all, and completely sidestepping issues of concurrency. In particular, dynamic issues of nonuniform service availability and conformance to protocols are not addressed by functional types. We propose a new type framework that characterizes objects as regular (finite state) processes that provide guarantees of service along public channels. We also propose a new notion of subtyping for active objects, based on Brinksma's notion of extension, that extends Wegner and Zdonik's "principle of substitutability" to nonuniform service availability. Finally, we formalize what it means to "satisfy a client's expectations," and we show how regular types canbe used...
AgentOriented Integration of Distributed Mathematical Services
 Journal of Universal Computer Science
, 1999
"... Realworld applications of automated theorem proving require modern software environments that enable modularisation, networked interoperability, robustness, and scalability. These requirements are met by the AgentOriented Programming paradigm of Distributed Artificial Intelligence. We argue that ..."
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Cited by 19 (10 self)
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Realworld applications of automated theorem proving require modern software environments that enable modularisation, networked interoperability, robustness, and scalability. These requirements are met by the AgentOriented Programming paradigm of Distributed Artificial Intelligence. We argue that a reasonable framework for automated theorem proving in the large regards typical mathematical services as autonomous agents that provide internal functionality to the outside and that, in turn, are able to access a variety of existing external services. This article describes...
The Entropy Theory of Symbolic Extensions
, 2002
"... Fix a topological system (X; T ), with its space K(X;T ) of T  invariant Borel probabilities. If (Y; S) is a symbolic system (subshift) and ' : (Y; S) ! (X; T ) is a topological extension (factor map), then the function ext on K(X;T ) which assigns to each the maximal entropy of a measure o ..."
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Cited by 15 (2 self)
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Fix a topological system (X; T ), with its space K(X;T ) of T  invariant Borel probabilities. If (Y; S) is a symbolic system (subshift) and ' : (Y; S) ! (X; T ) is a topological extension (factor map), then the function ext on K(X;T ) which assigns to each the maximal entropy of a measure on Y mapping to is called the extension entropy function of '. The in mum of such functions over all symbolic extensions is called the symbolic extension entropy function and is denoted by hsex . In this paper we completely characterize these functions in terms of functional analytic properties of an entropy structure on (X; T ). The entropy structure H is a sequence of entropy functions h k de ned with respect to a re ning sequence of partitions of X (or of X Z, for some auxiliary system (Z; R) with simple dynamics) whose boundaries have measure zero for all the invariant Borel probabilities.
The Type System of Aldor
 COMPUTING LABORATORY, UNIVERSITY OF KENT AT CANTERBURY, KENT
, 1999
"... This paper gives a formal description of  at least a part of  the type system of Aldor, the extension language of the computer algebra system AXIOM. In the process of doing this a critique of the design of the system emerges. ..."
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Cited by 7 (1 self)
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This paper gives a formal description of  at least a part of  the type system of Aldor, the extension language of the computer algebra system AXIOM. In the process of doing this a critique of the design of the system emerges.
Use of Complex Adaptive Systems for Modeling Global Change Ecosystems
 Biomedical and Life Sciences and Earth and Environmental Science
, 1998
"... Global modeling has been used for decades to assess the possible futures of humanity and the global environment. However, these models do not always satisfactorily include the adaptive characteristics of systems. In this article, a general approach is used to simulate change and transition at a macr ..."
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Cited by 5 (1 self)
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Global modeling has been used for decades to assess the possible futures of humanity and the global environment. However, these models do not always satisfactorily include the adaptive characteristics of systems. In this article, a general approach is used to simulate change and transition at a macrolevel due to adaptation at a microlevel. Tools from complex adaptive systems research are used to simulate the microlevel and consequently determine parameter values of the equationbased macrolevel model. Two case studies that applied this approach are reviewed. The first study assessed the efficacy of efforts to control malaria, whereas the second study used an integrated model to construct climate change scenarios by using various possible views on the nature of the climate system. Key words: complex adaptive systems; global change; climate change; malaria; multiagent modeling; adaptation; coevolution; genetic algorithms.
A logical framework for software proof reuse
 Proceedings of the ACM SIGSOFT Symposium on Software Reusability
, 1995
"... We describe a logical framework PR for verification of reusable software components. Within our system, developers can employ the advantages traditionally associated with software reuse to reduce the cost of software verification by reusing abstract proofs and specifications. One can construct an ..."
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Cited by 4 (0 self)
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We describe a logical framework PR for verification of reusable software components. Within our system, developers can employ the advantages traditionally associated with software reuse to reduce the cost of software verification by reusing abstract proofs and specifications. One can construct an algorithm with parameters, a specification with parameters, and a proof that the algorithm satisfies the specification provided the parameters satisfy certain conditions, Proofs in PR will themselves contain parameters for subproofs concerning those conditions. In this framework, typing, type checking, and proof checking are decidable. 1
Culture and identityprotective cognition: Explaining the whitemale effect in risk perception
, 2007
"... Why do white men fear various risks less than women and minorities? Known as the “whitemale effect, ” this pattern is well documented but poorly understood. This article proposes a new explanation: identityprotective cognition. Putting work on the cultural theory of risk together with work on motiv ..."
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Cited by 4 (1 self)
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Why do white men fear various risks less than women and minorities? Known as the “whitemale effect, ” this pattern is well documented but poorly understood. This article proposes a new explanation: identityprotective cognition. Putting work on the cultural theory of risk together with work on motivated cognition in social psychology suggests that individuals selectively credit and dismiss asserted dangers in a manner supportive of their cultural identities. This dynamic, it is hypothesized, drives the whitemale effect, which reflects the risk skepticism that hierarchical and individualistic white males display when activities integral to their cultural identities are challenged as harmful. The article presents the results of an 1,800person study that confirmed that cultural worldviews interact with the impact of gender and race on risk perception in patterns that suggest culturalidentityprotective cognition. It also discusses the implications of these findings for risk regulation and communication. Fear discriminates. Numerous studies show that risk perceptions are skewed across gender and race: women worry more than men, and minorities more than whites, about myriad dangers—from environmental pollution to
The Structure of the Social
, 2000
"... This article seeks to develop the Marxist conception of social structure by incorporating developments within critical realist philosophy. It rejects forms of economic determinism such as the basesuperstructure model and those reconstructions—like Cohen’s—that attribute primacy to productive forces ..."
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Cited by 2 (0 self)
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This article seeks to develop the Marxist conception of social structure by incorporating developments within critical realist philosophy. It rejects forms of economic determinism such as the basesuperstructure model and those reconstructions—like Cohen’s—that attribute primacy to productive forces in explaining history and society. It argues instead that society is the product of complex, often contradictory combinations of many different structures and mechanisms. They form a structural ensemble, hierarchically arranged, but where each element has its own dynamics and emergent powers. It concludes that society is best understood through critical realist conceptions of stratification, emergence, transformation, and overdetermination. This article seeks to develop the Marxist conception of social structure by incorporating developments within critical realist philosophy. It rejects forms of economic determinism and those reconstructions that attribute primacy to productive forces in explaining history and society. We propose a stratified conception of the social based on the