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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 17 (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...
On electrical correlates of Physarum polycephalum spatial activity: Can we see
 Physarum Machine in the dark? Biophysical Reviews and Letters 6
, 2011
"... Abstract. Plasmodium of Physarum polycephalum is a single cell visible by unaided eye, which spans sources of nutrients with its protoplasmic network. In a very simple experimental setup we recorded electric potential of the propagating plasmodium. We discovered a complex interplay of short range o ..."
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Cited by 8 (5 self)
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Abstract. Plasmodium of Physarum polycephalum is a single cell visible by unaided eye, which spans sources of nutrients with its protoplasmic network. In a very simple experimental setup we recorded electric potential of the propagating plasmodium. We discovered a complex interplay of short range oscillatory behaviour combined with long range, low frequency oscillations which serve to communicate information between different parts of the plasmodium. The plasmodium’s response to changing environmental conditions forms basis patterns of electric activity, which are unique indicators of the following events: plasmodium occupies a site, plasmodium functions normally, plasmodium becomes ‘agitated ’ due to drying substrate, plasmodium departs a site, and plasmodium forms sclerotium. Using a collective particle approximation of Physarum polycephalum we found matching correlates of electrical potential in computational simulations by measuring local population flux at the node positions, generating trains of high and low frequency oscillatory behaviour. Motifs present in these measurements matched the response ‘grammar ’ of the plasmodium when encountering new nodes, simulated consumption of nutrients, exposure to simulated hazardous illumination and sclerotium formation. The distributed computation of the particle collective was able to calculate beneficial network structures and sclerotium position by shifting the active growth zone of the simulated plasmodium. The results show future promise for the noninvasive study of the complex dynamical behaviour within — and health status of — living systems.
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.
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).
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.
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.