Papers by Yaroslav Usenko
Isola, 2004
This paper gives an impression of the language modest, a modelling and description language for s... more This paper gives an impression of the language modest, a modelling and description language for stochastic and timed systems, and reports on applications of this language to a variety of industrial case studies. The language and its accompanying tool environment, motor, support the modular description and analysis of reactive systems while covering both functional and non-functional system aspects such as hard and soft real-time, and quality-of-service aspects. This unique expressiveness has been exploited in three recent industrial case studies of rather different nature, ranging from (i) schedule synthesis and evaluation for a lacquer production plant, to (ii) device detection in a plug-and-play infotainment protocol, and to (iii) dependability assessment of an emerging standard for future high-speed cross-European trains.
Discretization of timed automata in Timed �CRL � la regions and zones
Entcs, 2006
This paper describes the initial steps in the discretization of a timed μCRL process equation rep... more This paper describes the initial steps in the discretization of a timed μCRL process equation representing a timed automaton. If the fractional parts of the time stamps of the actions are neglected, the translation results in a timed bisimilar representation with only discrete parameters and bound variables. To this end we apply “standard” techniques such as coordinate transformation and abstraction.
Computer Physics Communications, 2000
We describe a linearization algorithm for parallel pCRL processes similar to the one implemented ... more We describe a linearization algorithm for parallel pCRL processes similar to the one implemented in the linearizer of the mcrl Toolset. This algorithm finds its roots in formal language theory: the `grammar' defining a process is transformed into a variant of Greibach Normal Form. Next, any such form is further reduced to emph{linear form, i.e., to an equation that resembles
Proceedings of the 5th international workshop on Software and performance - WOSP '05, 2005
StoCharts have been proposed as a UML statechart extension for performance and dependability eval... more StoCharts have been proposed as a UML statechart extension for performance and dependability evaluation, and have been applied in the context of train radio reliability assessment to show the principal tractability of realistic cases with this approach. In this paper, we extend on this bare feasibility result in two important directions. First, we sketch the cornerstones of a mechanizable translation of StoCharts to MoDeST. The latter is a process algebra-based formalism supported by the MOTOR/MÖBIUS tool tandem. Second, we exploit this translation for a detailed analysis of the train radio case study.
Lecture Notes in Computer Science, 2002
Lecture Notes in Computer Science, 2010
ToolBus allows to connect tools via a software bus. Programming is done using the scripting langu... more ToolBus allows to connect tools via a software bus. Programming is done using the scripting language Tscript, which is based on the process algebra ACP. In previous work we presented a method for analyzing a Tscript by translating it to the process algebraic language mCRL2, and then applying model checking to verify certain behavioral properties. We have implemented a prototype based on this approach. As a case study, we have applied it on a standard example from the ToolBus distribution, distributed auction, and detected a number of behavioral irregularities in this auction Tscript.
Lecture Notes in Computer Science, 2008
This paper reports the analysis of an industrial implementation of the session-layer of a load-ba... more This paper reports the analysis of an industrial implementation of the session-layer of a load-balancing software system. This software comprises 7.5 thousand lines of C code. It is used for distribution of the print jobs among several document processors (workers). A large part of this commercially used software system has been modeled closely and analyzed using process-algebraic techniques. Several critical issues were discovered. Since the model was close to the code, all problems that were found in the model, could be traced back to the actual code resulting in concrete suggestions for improvement of the code. All in all, the analysis significantly improved the quality of this real-life system.
Lecture Notes in Computer Science, 2008
ToolBus allows one to connect tools via a software bus. Programming is done using the scripting l... more ToolBus allows one to connect tools via a software bus. Programming is done using the scripting language Tscript, which is based on the process algebra ACP. Tscript was originally designed to enable formal verification, but this option has so far not been explored in any detail. We present a method for analyzing a Tscript by translating it to the process algebraic language mCRL2, and then applying model checking to verify behavioral properties.
Discrete Time Process Algebra and the Semantics of SDL
Handbook of Process Algebra, 2001
... In particular the communications with Leonard Pruitt 12] provided convincing practical justi ... more ... In particular the communications with Leonard Pruitt 12] provided convincing practical justi cation for the premise of our choices: provided time is divided into su ciently large time slices, an SDL process will only enter a next time slice if there are no more signals to consume for it ...
The Theorema project aims at integrating computation and deduction in a system that can be used b... more The Theorema project aims at integrating computation and deduction in a system that can be used by the working scientist for building and checking mathematical models, including the design and veri cation of new algorithms. Currently, the system uses the rewrite engine of the computer algebra system Mathematica for building and combining a number of automatic/interactive provers (high-order predicate-logic, induction for lists/tuples and natural numbers, etc.) in natural deduction style and in natural language presentation. These provers can be used for de ning and proving properties of mathematical models and algorithms, while a specially provided \computing engine" can execute directly the logical description of these algorithms.
StoCharts have been proposed as a UML statechart extension for performance and dependability eval... more StoCharts have been proposed as a UML statechart extension for performance and dependability evaluation, and were applied in the context of train radio reliability assessment to show the principal tractability of realistic cases with this approach. In this paper, we extend on this bare feasibility result in two important directions. First, we sketch the cornerstones of a mechanizable translation of
From µCRL to mCRL2 : motivation and outline
We sketch the language mCRL2, the successor of μCRL, which is a process algebra with data, devise... more We sketch the language mCRL2, the successor of μCRL, which is a process algebra with data, devised in 1990 to model and study the behaviour of interacting programs and systems. The language is improved in several respects guided by the experience obtained from numerous applications where realistic systems have been modelled and analysed. Just as with μCRL, the leading principle
Analysis of Distributed Systems with mCRL2
Chapman & Hall/CRC Computational Science, 2008
The Journal of Logic and Algebraic Programming, 2001
We describe a linearization algorithm for parallel pCRL processes similar to the one implemented ... more We describe a linearization algorithm for parallel pCRL processes similar to the one implemented in the linearizer of the CRL Toolset. This algorithm finds its roots in formal language theory: the 'grammar' defining a process is transformed into a variant of Greibach Normal Form. Next, any such form is further reduced to linear form, i.e., to an equation that resembles a right-linear, dataparametric grammar. We aim at proving the correctness of this linearization algorithm. To this end we define an equivalence relation on recursive specifications in CRL that is model independent and does not involve an explicit notion of solution.
From μCRL to mCRL2
Electronic Notes in Theoretical Computer Science, 2006
We sketch the language mCRL2, the successor of μCRL, which is a process algebra with data, devise... more We sketch the language mCRL2, the successor of μCRL, which is a process algebra with data, devised in 1990 to model and study the behaviour of interacting programs and systems. The language is improved in several respects guided by the experience obtained from numerous applications where realistic systems have been modelled and analysed. Just as with μCRL, the leading principle
The formal specification language mCRL2
We introduce mCRL2, a specification language that can be used to specify and analyse the behaviou... more We introduce mCRL2, a specification language that can be used to specify and analyse the behaviour of distributed systems. This language is the successor of the mCRL specification language. The mCRL2 language extends a timed basic process algebra with the possibility to define and use abstract data types. The mCRL2 data language features predefined and higher-order data types. The process
Proceedings of the …, 2007
1 Institute for Computing and Information Sciences, Radboud Universiteit Nijmegen, PO Box 9102, 6... more 1 Institute for Computing and Information Sciences, Radboud Universiteit Nijmegen, PO Box 9102, 6500 HC Nijmegen, The Netherlands 2 Aia Software BV PO Box 38025, 6503 AA Nijmegen, The Netherlands 3 Laboratory for Quality Software (LaQuSo), Technische ...
Synthesis and stochastic assessment of schedules for lacquer production
The M modeling language pairs modeling features from stochastic process algebra and from tim... more The M modeling language pairs modeling features from stochastic process algebra and from timed and proba- bilistic automata with light-weight notations such as excep- tion handling. It is supported by the M tool, which fa- cilitates the execution and evaluation of M specifica- tions by means of the discrete event simulation engine of the M¨ tool. This paper describes
In industry, many business processes are modelled and stored in Enterprise Information Systems (E... more In industry, many business processes are modelled and stored in Enterprise Information Systems (EIS). Tools supporting the verification and validation of business processes can help to improve the quality of these business processes. However, existing tools can not directly be applied to models used in industry.
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Papers by Yaroslav Usenko