| 11. |
- Aceto, Luca, et al.
(författare)
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Rule formats for determinism and idempotence
- 2012
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Ingår i: Science of Computer Programming. - Amsterdam : Elsevier BV. - 0167-6423 .- 1872-7964. ; 77:7-8, s. 889-907
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Tidskriftsartikel (refereegranskat)abstract
- Determinism is a semantic property of (a fragment of) a language that specifies that a program cannot evolve operationally in several different ways. Idempotence is a property of binary composition operators requiring that the composition of two identical specifications or programs will result in a piece of specification or program that is equivalent to the original components. In this paper, we propose (related) meta-theorems for guaranteeing the determinism and idempotence of binary operators. These meta-theorems are formulated in terms of syntactic templates for operational semantics, called rule formats. In order to obtain a powerful rule format for idempotence, we make use of the determinism of certain transition relations in the definition of the format for idempotence. We show the applicability of our formats by applying them to various operational semantics from the literature.
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| 12. |
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| 13. |
- Ashraf, Samaneh, et al.
(författare)
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Compounding effects of human activities and climatic changes on surface water availability in Iran
- 2019
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Ingår i: Climatic Change. - : Springer Science and Business Media LLC. - 0165-0009 .- 1573-1480. ; 152:3-4, s. 379-391
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Tidskriftsartikel (refereegranskat)abstract
- By combining long-term ground-based data on water withdrawal with climate model projections, this study quantifies the compounding effects of human activities and climate change on surface water availability in Iran over the twenty-first century. Our findings show that increasing water withdrawal in Iran, due to population growth and increased agricultural activities, has been the main source of historical water stress. Increased levels of water stress across Iran are expected to continue or even worsen over the next decades due to projected variability and change in precipitation combined with heightened water withdrawals due to increasing population and socio-economic activities. The greatest rate of decreased water storage is expected in the Urmia Basin, northwest of Iran, (varying from -8.3mm/year in 2010-2039 to -61.6mm/year in 2070-2099 compared with an observed rate of 4mm/year in 1976-2005). Human activities, however, strongly dominate the effects of precipitation variability and change. Major shifts toward sustainable land and water management are needed to reduce the impacts of water scarcity in the future, particularly in Iran's heavily stressed basins like Urmia Basin, which feeds the shrinking Lake Urmia.
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| 14. |
- Jaghoori, Mohammad Mahdi, et al.
(författare)
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Symmetry and partial order reduction techniques in model checking Rebeca
- 2010
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Ingår i: Acta Informatica. - New York : Springer. - 0001-5903 .- 1432-0525. ; 47:1, s. 33-66
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Tidskriftsartikel (refereegranskat)abstract
- Rebeca is an actor-based language with formal semantics which is suitable for modeling concurrent and distributed systems and protocols. Due to its object model, partial order and symmetry detection and reduction techniques can be efficiently applied to dynamic Rebecamodels. We present two approaches for detecting symmetry in Rebeca models: One that detects symmetry in the topology of inter-connections among objects and another one which exploits specific data structures to reflect internal symmetry in the internal structure of an object. The former approach is novel in that it does not require any input from the modeler and can deal with the dynamic changes of topology. This approach is potentially applicable to a wide range of modeling languages for distributed and reactive systems. We have also developed a model checking tool that implements all of the above-mentioned techniques. The evaluation results show significant improvements in model size and model-checkingtime.
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| 15. |
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| 16. |
- Jamshidian, Hajar, et al.
(författare)
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Implications of recovery procedures on structural and rheological properties of schizophyllan produced from date syrup
- 2017
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Ingår i: International Journal of Biological Macromolecules. - : Elsevier. - 0141-8130 .- 1879-0003. ; 105, s. 36-44
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates the effects of different recovery procedures on high molar mass schizophyl-Ian produced by Schizophyllum commune using low value agricultural residues. Recovered extracellular polysaccharides (EPSs) were compared in terms of purity, sugar composition, degree of branching, molecular weight, and rheological properties. Performing different recovery methods, such as re-dissolving in water and re-precipitation with ethanol on produced EPS, provided schizophyllan with purity similar to the commercial grade. Besides, Freeze-thawing cycles allowed the fractionation of schizophyllan based on branching degree and solubility. The EPSs with higher purity and lower degree of branching (less conformational flexibility) showed higher viscosity. This study evidences the possibility of producing EPSs with excellent rheological properties using low value agricultural side products. Furthermore, our results demonstrate the importance of recovery methods for tailoring the purity, molecular structure and macroscopic properties of the produced polysaccharides for specific applications.
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| 17. |
- Khakpour, Narges, et al.
(författare)
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Formal modeling of evolving self-adaptive systems
- 2012
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Ingår i: Science of Computer Programming. - Amsterdam : Elsevier. - 0167-6423 .- 1872-7964. ; 78:1, s. 3-26
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present a formal model, named PobSAM (Policy-based Self-Adaptive Model), for developing and modeling self-adaptive evolving systems. In this model, policies are used as a mechanism to direct and adapt the behavior of self-adaptive systems. A PobSAM model is a collection of autonomous managers and managed actors. The managed actors are dedicated to the functional behavior while the autonomous managers govern the behavior of managed actors by enforcing suitable policies. A manager has a set of configurations including two types of policies: governing policies and adaptation policies. To adapt the system behavior in response to the changes, the managers switch among different configurations. We employ the combination of an algebraic formalism and an actor-based model to specify this model formally. Managed actors are expressed by an actor model. Managers are modeled as meta-actors whose configurations are described using a multi-sorted algebra called CA. We provide an operational semantics for PobSAM using labeled transition systems. Furthermore, we provide behavioral equivalence of different sorts of CA in terms of splitting bisimulation and prioritized splitting bisimulation. Equivalent managers send the same set of messages to the actors. Using our behavioral equivalence theory, we can prove that the overall behavior of the system is preserved by substituting a manager by an equivalent one.
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| 18. |
- Khakpour, Narges, et al.
(författare)
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PobSAM : policy-based managing of actors in self-adaptive systems
- 2010
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Ingår i: Proceedings of the 6th International Workshop on Formal Aspects of Component Software (FACS’09, Eindhoven, The Netherlands, November 2-3, 2009). - Amsterdam : Elsevier. ; 263, s. 129-143
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Konferensbidrag (refereegranskat)
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| 19. |
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| 20. |
- Aceto, Luca, et al.
(författare)
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A Rule Format for Unit Elements
- 2009
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This paper offers a meta-theorem for languages with a Structural Operational Semantics (SOS) in the style of Plotkin. Namely, it proposes a generic rule format for SOS guaranteeing that certain constants act as left- or right-unit elements for a set of binary operators. We show the generality of our format by applying it to a wide range of operators from the literature on process calculi.
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