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100 Mb/s data transmission on UTP and STP cabling for demand priority networks

A.N. Coles, D.G. Cunningham, S.G. Methley
1995 IEEE Journal on Selected Areas in Communications  
This binary signaling scheme is shown to provide better immunity against crosstalk and external (impulse) noise than multilevel signaling schemes.  ...  This binary signalling scheme is shown to provide better immunity against crosstalk and external (impulse) noise than multilevel signalling schemes.  ...  In section II we present an analysis of two approaches to looMb/s transmission on UTP cable: multilevel signalling and multipair signalling.  ... 
doi:10.1109/49.475540 fatcat:pt775xzhgzgu3d4263sge5weem

Prioritized slotted-Circus [chapter]

Paweł Gancarski, Andrew Butterfield
2010 Lecture Notes in Computer Science  
The semantics of prioritised external choice is given using the Unifying Theories of Programming framework (UTP).  ...  definitions are in fact 1st-order, but we need 2nd-order in order to handle the notion of "healthiness", and recursion.  ...  Acknowledgements We would like to thank Jim Woodcock and his colleagues for many fruitful discussions on various aspects of this work.  ... 
doi:10.1007/978-3-642-14808-8_7 fatcat:f4gzlhoctvg4fksopjof2lkaca

Automating Verification of State Machines with Reactive Designs and Isabelle/UTP [article]

Simon Foster, James Baxter, Ana Cavalcanti, Alvaro Miyazawa, Jim Woodcock
2018 arXiv   pre-print
The work has been mechanised in our proof tool, Isabelle/UTP, and so also illustrates the use of UTP to build practical verification tools.  ...  In this paper, we present a verification approach for a diagrammatic state machine language that utilises theorem proving and a denotational semantics based on Unifying Theories of Programming (UTP).  ...  External choice, 2 i ∈ A • P (i ) indexed by set A, as in CSP, permits one of the branches to resolve either by an event, or by termination. A binary choice P 2 Q is denoted by 2 X ∈ {P , Q} • X .  ... 
arXiv:1807.08588v1 fatcat:nboohuqn3rh7dmmax7cqud4taa

A Stepwise Approach to Linking Theories [chapter]

Pedro Ribeiro, Ana Cavalcanti, Jim Woodcock
2017 Lecture Notes in Computer Science  
Here, we propose a stepwise approach to linking theories where we deal separately with the definition of the relation between the variables in the different theories and the identification of healthiness  ...  We explore this approach by deriving healthiness conditions for Circus Time via calculation, based on the healthiness conditions of CSP and a small set of principles underlying the timed model.  ...  Acknowledgments We would like to thank Simon Foster for his support regarding Isabelle/UTP. This work is funded by EPSRC grants EP/H017461/1 and EP/M025756/1.  ... 
doi:10.1007/978-3-319-52228-9_7 fatcat:oehfydumlndtjdtxwalpeev6si

Timed Circus: Timed CSP with the Miracle

Kun Wei, Jim Woodcock, Alan Burns
2011 2011 16th IEEE International Conference on Engineering of Complex Computer Systems  
Finally, we use a simple example to demonstrate how our model can contribute to modelling temporal behaviours with multiple time scales in complex systems.  ...  In this paper, compared with timed CSP, we will extensively explore such strange processes which turn out to be very useful in specifying a distinct property that 'something must occur'.  ...  ACKNOWLEDGEMENTS We would like to thank Ana Cavalcanti, Leo Freitas, Andrew Butterfield and Paweł Gancarski for discussions on the role of reactive miracles in programming logic, and thank Cliff Jones  ... 
doi:10.1109/iceccs.2011.13 dblp:conf/iceccs/WeiWB11 fatcat:45cv7nhpwnbd7gnyyh5m6wguzu

Calculational Verification of Reactive Programs with Reactive Relations and Kleene Algebra [chapter]

Simon Foster, Kangfeng Ye, Ana Cavalcanti, Jim Woodcock
2018 Lecture Notes in Computer Science  
Our laws and strategy are mechanised in Isabelle/UTP, which provides soundness guarantees, and practical verification support.  ...  Preliminaries Kleene Algebras [8] (KA) characterise sequential and iterative behaviour in nondeterministic programs using a signature (K , +, 0, ·, 1, * ), where + is a choice operator with unit 0, and  ...  We use these to define indexed external choice.  ... 
doi:10.1007/978-3-030-02149-8_13 fatcat:2mlcyy36qvgnjj5f4v54556g7q

A Timed Model of Circus with the Reactive Design Miracle

Kun Wei, Jim Woodcock, Alan Burns
2010 2010 8th IEEE International Conference on Software Engineering and Formal Methods  
We propose a timed model of Circus which is a compact extension of original Circus. Apart from introducing time, this model uses UTP-style semantics to describe each process as a reactive design.  ...  One of significant contributions of our timed model is to extensively explore the reactive design miracle, the top element of a complete lattice with respect to the implication ordering.  ...  ACKNOWLEDGMENT We would like to thank Ana Cavalcanti, Leo Freitas, Andrew Butterfiel and Pawel Gancarski for discussions on the role of reactive miracles in programming logic.  ... 
doi:10.1109/sefm.2010.40 dblp:conf/sefm/WeiWB10 fatcat:bnxgvzyhtnaudd6743rie5ekwu

Calculational Verification of Reactive Programs with Reactive Relations and Kleene Algebra [article]

Simon Foster, Kangfeng Ye, Ana Cavalcanti, Jim Woodcock
2018 arXiv   pre-print
Our laws and strategy are mechanised in Isabelle/UTP, which provides soundness guarantees, and practical verification support.  ...  We define novel operators to characterise interactions and state updates, and an associated equational theory.  ...  We use these to define indexed external choice.  ... 
arXiv:1806.02101v2 fatcat:nsxrfpwiqvh3lmothiqv4ga6wm

Unifying Theories of Reactive Design Contracts [article]

Simon Foster, Ana Cavalcanti, Samuel Canham, Jim Woodcock, Frank Zeyda
2019 arXiv   pre-print
Practical reasoning support is provided via our proof framework, Isabelle/UTP, including a proof tactic that reduces a conjecture about a reactive program to three predicates, symbolically characterising  ...  Being based in Unifying Theories of Programming (UTP), our theory can be composed with further computational theories to support semantics for multi-paradigm languages.  ...  We would like to thank our colleagues on this project, particularly those from Peter Gorm Larsen's group atÅrhus University, for their collaboration over the past three years, without which this work could  ... 
arXiv:1712.10233v2 fatcat:nucijwgabvbx5e2takfqiubtou

A process algebraic framework for specification and validation of real-time systems

Adnan Sherif, Ana Cavalcanti, He Jifeng, Augusto Sampaio
2009 Formal Aspects of Computing  
Acknowledgments We are grateful to Jim Woodcock for his detailed comments on our work. The work of Augusto Sampaio is partially funded by the Brazilian Research Council (CNPq).  ...  In Circus Time, we take a similar approach, but we need to consider time.  ...  It makes a choice of either terminating after 2 time units (Wait 2) or after three time units (Wait 3). If we used the CSP definition of external choice above, we could conclude the following.  ... 
doi:10.1007/s00165-009-0119-6 fatcat:4ewl5hwsmfd5doh6j34wpsx664

Foundations for Model-Based Engineering of Systems of Systems [chapter]

John Fitzgerald, Peter Gorm Larsen, Jim Woodcock
2014 Complex Systems Design & Management  
(UTP).  ...  Three priorities for current research are identified: contractual interface definition, the verification of emergent behaviour, and the need to deal with semantic heterogeneity of constituent systems and  ...  The authors are grateful to their many collaborators in the project.  ... 
doi:10.1007/978-3-319-02812-5_1 dblp:conf/csdm/FitzgeraldLW13 fatcat:76jhkkdhkjbhxbdtvaofjscphm

Automated Verification of Reactive and Concurrent Programs by Calculation [article]

Simon Foster, Kangfeng Ye, Ana Cavalcanti, Jim Woodcock
2021 arXiv   pre-print
Our laws and strategy are mechanised in Isabelle/UTP, our implementation of Hoare and He's Unifying Theories of Programming (UTP) framework, to provide soundness guarantees and practical verification support  ...  They are ubiquitous in modern applications, ranging from components systems and web services, to cyber-physical systems and autonomous robots.  ...  We would like to thank the anonymous reviewers of our article for their diligent and helpful feedback, which has greatly improved the presentation of our results.  ... 
arXiv:2007.13529v2 fatcat:v2xwbwr7pvc3de5m7gp53gbv44

TaskUniVerse: A Task-Based Unified Interface for Versatile Parallel Execution [article]

Afshin Zafari
2017 arXiv   pre-print
In this approach we abstract the common concepts of task based parallel programming and provide them to the programmer in a single programming interface uniformly for all frameworks.  ...  Different approaches are used by different software development frameworks to provide these outcomes to the programmer, while making the underlying hardware architecture transparent to her.  ...  Acknowledgments Thanks to Assoc. Prof. Elisabeth Larsson 1 for her valuable comments on improving the quality of this paper. The computations were performed on resources pro-  ... 
arXiv:1705.02970v1 fatcat:6xiexu3bbjejffcb2zl6aoz3ju

UTCP: Compositional Semantics for Shared-Variable Concurrency [chapter]

Andrew Butterfield
2017 Lecture Notes in Computer Science  
Here we take a more direct approach, albeit inspired by the action-systems view, based on an abstract notion of label generation, that then exploits the standard use of substitution in UTP, to obtain a  ...  Previous work was based on mapping such programs, using labelling of decision points and atomic actions, to action systems, which themselves were provided with a UTP semantics.  ...  We also hope to use this semantics as a baseline for a program to apply UTP to model the various linked approaches discussed in the Views paper [10] .  ... 
doi:10.1007/978-3-319-70848-5_16 fatcat:pu3hkizpwng6nb3hko4etp52si

Contracts in CML [chapter]

Jim Woodcock, Ana Cavalcanti, John Fitzgerald, Simon Foster, Peter Gorm Larsen
2014 Lecture Notes in Computer Science  
Every process construct in CML has an associated contract, allowing clients and suppliers to check that the implementations of constituent systems conform to their interface specications.  ...  The language can be used to document the interfaces to constituent systems using formal, precise, and veriable specications including preconditions, postconditions, and invariants.  ...  Time. The theory of timed traces in UTP supports the observation of events in discrete time. It is used in a theory of Timed CSP.  ... 
doi:10.1007/978-3-662-45231-8_5 fatcat:a7rqhg5jonesnhghaltkmgfxhq
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