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Reasoning About Concurrent Objects
 In: Proc. AsiaPacific Software Engineering Conf. (APSEC '95), IEEE, Los Alamitos, Cal
, 1995
"... Embedded specifications in objectoriented (OO) languages such as Eiffel and Sather are based on a rigorous approach towards validation, compatibility and reusability of sequential programs. The underlying method of "designbycontract" is based on Hoare logic for which concurrency extensi ..."
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Cited by 16 (7 self)
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Embedded specifications in objectoriented (OO) languages such as Eiffel and Sather are based on a rigorous approach towards validation, compatibility and reusability of sequential programs. The underlying method of "designbycontract" is based on Hoare logic for which concurrency extensions exist. However concurrent OO languages are still in their infancy. They have inherently imperative facets, such as object identity, sharing, and synchronisation, which cannot be ignored in the semantics. Any marriage of objects and concurrency requires a tradeoff in a space of intertwined qualities. This paper summarises our work on a type system, calculus and an operational model for concurrent objects in a minimal extension of the Eiffel and Sather languages (cSather). We omit concurrency control constructs and instead use assertions as synchronisation constraints for asynchronous functions. We show that this provides a framework in which subtyping and concurrency can coexist. 1 Introduction C...
A Complexity Calculus for ObjectOriented Programs
 Journal of ObjectOriented Systems
, 1994
"... Modern imperative objectoriented design methods and languages take a rigorous approach to compatibility and reusability mainly from an interface and specification point of view  if at all. Beside functional specification, however, users select classes from libraries based on performance characte ..."
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Cited by 12 (6 self)
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Modern imperative objectoriented design methods and languages take a rigorous approach to compatibility and reusability mainly from an interface and specification point of view  if at all. Beside functional specification, however, users select classes from libraries based on performance characteristics, too. This article develops an appropriate fundamental approach towards performance estimation, measurement and metering in OO approaches. We use examples written in the Sather language to demonstrate the concepts of socalled OOmachines, which lend themselves to performance metrics, and a calculus for reasoning about performance. A language binding of these concepts is then sketched in the form of cost annotations that allow programmers to file classes in libraries welldocumented with cost related specifications. These annotations can optionally be used for instrumenting code that meters cost and checks whether the taken measurements are consistent with the given specification. In...
Reasoning about Complexity of ObjectOriented Programs
, 1994
"... This report develops an appropriate fundamental approach towards performance estimation, measurement and metering in OO approaches. We use examples written in the Sather language to demonstrate the concepts of socalled OOmachines, which lend themselves to performance metrics, and a calculus for re ..."
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Cited by 4 (4 self)
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This report develops an appropriate fundamental approach towards performance estimation, measurement and metering in OO approaches. We use examples written in the Sather language to demonstrate the concepts of socalled OOmachines, which lend themselves to performance metrics, and a calculus for reasoning about performance. A language binding of these concepts is then sketched in the form of cost annotations that allow programmers to file classes in libraries welldocumented with cost related specifications. These annotations can optionally be used for instrumenting code that meters cost and checks whether the taken measurements are consistent with the given specification. In this way programmers can benefit from cost annotations by means of documentation and rigorous testing without requiring a deep familiarity with the theoretical underpinnings. Keywords: ObjectOriented Languages, Complexity, Amortized Complexity
Relative Complexity of Algebras
, 1981
"... A simple algebraic model is proposed fr measuring the relative complexity of programming systems. The appropriateness of this model is illustrated by its use as a framework for the statement and proof of results dealing with codingindependent limitations on the relative complexity of basic alge ..."
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Cited by 3 (1 self)
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A simple algebraic model is proposed fr measuring the relative complexity of programming systems. The appropriateness of this model is illustrated by its use as a framework for the statement and proof of results dealing with codingindependent limitations on the relative complexity of basic algebras.
Programmable reconfiguration of Physarum
, 901
"... Plasmodium of Physarum polycephalum is a large cell capable of solving graphtheoretic, optimization and computational geometry problems due to its unique foraging behavior. Also the plasmodium is unique biological substrate that mimics universal storage modification machines, namely the KolmogorovU ..."
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Plasmodium of Physarum polycephalum is a large cell capable of solving graphtheoretic, optimization and computational geometry problems due to its unique foraging behavior. Also the plasmodium is unique biological substrate that mimics universal storage modification machines, namely the KolmogorovUspensky machine. In the plasmodium implementation of the storage modification machine data are represented by sources of nutrients and memory structure by protoplasmic tubes connecting the sources. In laboratory experiments and simulation we demonstrate how the plasmodiumbased storage modification machine can be programmed. We show execution of the following operations with active zone (where computation occurs): merge two active zones, multiple active zone, translate active zone from one data site to another, direct active zone. Results of the paper bear twofold value: they provide a basis for programming unconventional devices based on biological substrates and also shed light on behavioral patterns of the plasmodium. Keywords: Physarum polycephalum, KolmogorovUspensky machine, pattern formation, morphogenesis, graph theory
Systems Theory Relative Complexity of Algebras
"... Abstract. A simple algebraic model is proposed for measuring the relative complexity of programming systems. The appropriateness of this model is illustrated by its use as a framework for the statement and proof of results dealing with codingindependent limitations on the relative complexity of bas ..."
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Abstract. A simple algebraic model is proposed for measuring the relative complexity of programming systems. The appropriateness of this model is illustrated by its use as a framework for the statement and proof of results dealing with codingindependent limitations on the relative complexity of basic algebras. I.
Towards an ObjectOriented Programming Language for Physarum Polycephalum Computing
"... Abstract. In the paper, we present foundations of a new objectoriented programming language for Physarum polycephalum computing. Both, theoretical foundations and assumptions for a language specification are considered. Physarum polycephalum is a onecell organism. In the phase of plasmodium, its b ..."
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Abstract. In the paper, we present foundations of a new objectoriented programming language for Physarum polycephalum computing. Both, theoretical foundations and assumptions for a language specification are considered. Physarum polycephalum is a onecell organism. In the phase of plasmodium, its behavior can be regarded as a biological substrate that implements the KolmogorovUspensky machine which is the most generalized and natureoriented version of a mathematical machine. The proposed language will be used for developing programs for Physarum polycephalum by the spatial configuration of stationary nodes (inputs).
LBNL59102 Two Strategies to Speed up Connected Component Labeling Algorithms
"... Abstract — This paper presents two new strategies to speed up connected component labeling algorithms. The first strategy employs a decision tree to minimize the work performed in the scanning phase of connected component labeling algorithms. The second strategy uses a simplified unionfind data str ..."
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Abstract — This paper presents two new strategies to speed up connected component labeling algorithms. The first strategy employs a decision tree to minimize the work performed in the scanning phase of connected component labeling algorithms. The second strategy uses a simplified unionfind data structure to represent the equivalence information among the labels. For 8connected components in a twodimensional (2D) image, the first strategy reduces the number of neighboring pixels visited from 4 to 7/3 on average. In various tests, using a decision tree decreases the scanning time by a factor of about 2. The second strategy uses a compact representation of the unionfind data structure. This strategy significantly speeds up the labeling algorithms. We prove analytically that a labeling algorithm with our simplified unionfind structure has the same optimal theoretical time complexity as do the best labeling algorithms. By extensive experimental measurements, we confirm the expected performance characteristics of the new labeling algorithms and demonstrate that they are faster than other optimal labeling algorithms. Index Terms — Connected component labeling, optimization, unionfind algorithm, decision tree, equivalence relation. I.