Zwelgje Bommel - Academia.edu (original) (raw)
Papers by Zwelgje Bommel
Analysis of Ethernet-Switch Traffic Shapers for In-Vehicle Networking Applications
Towards Budgeting in Real-Time Calculus: Deferrable Servers
Lecture Notes in Computer Science, 2007
Budgeting of resources is an often used solution for guaranteeing performance of lower priority t... more Budgeting of resources is an often used solution for guaranteeing performance of lower priority tasks. In this paper, we take a formal approach to the modeling of a deferrable server budgeting strategy, using real-time calculus. We prove a scheduling theorem for deferrable servers, and as a corollary show that an earlier claim of Davis and Burns, that periodic servers dominate
Two different lines of research are presented in the study of an industrially relevant problem of... more Two different lines of research are presented in the study of an industrially relevant problem of impact con- trol. One is focused on actual control of the process, while the other is focused on the development of a general lan- guage for modeling hybrid systems, of which the case study is an appropriate example.
Lecture Notes in Computer Science, 2010
Automata theory presents roughly three types of automata: finite automata, pushdown automata and ... more Automata theory presents roughly three types of automata: finite automata, pushdown automata and Turing machines. The automata are treated as language acceptors, and the expressiveness of the automata models are considered modulo language equivalence. This notion of equivalence is arguably too coarse to satisfactorily deal with a notion of interaction that is fundamental to contemporary computing. In this paper we therefore reconsider the automaton models from automata theory modulo branching bisimilarity, a well-known behavioral equivalence from process theory that has proved to be able to satisfactorily deal with interaction. We investigate to what extent some standard results from automata theory are still valid if branching bisimilarity is adopted as the preferred equivalence.
Electronic Proceedings in Theoretical Computer Science, 2010
The task of implementing a supervisory controller is non-trivial, even though different theories ... more The task of implementing a supervisory controller is non-trivial, even though different theories exist that allow automatic synthesis of these controllers in the form of automata. One of the reasons for this discord is due to the asynchronous interaction between a plant and its controller in implementations, whereas the existing supervisory control theories assume synchronous interaction. As a consequence the implementation suffer from the so-called inexact synchronisation problem. In this paper we address the issue of inexact synchronisation in a process algebraic setting, by solving a more general problem of refinement. We construct an asynchronous closed loop system by introducing a communication medium in a given synchronous closed loop system. Our goal is to find sufficient conditions under which a synchronous closed loop system is branching bisimilar to its corresponding asynchronous closed loop system.
The categorical limit of a sequence of dynamical systems
Electronic Proceedings in Theoretical Computer Science, 2013
Desynchronisablity of (partial) closed loop systems
Simulation of Drift Control for an Electron Microscope Stage Using Image Processing in the Loop
2013 IEEE International Conference on Pervasive Computing and Communications Workshops (PERCOM Workshops), 2013
ABSTRACT Software reprogramming enables users to extend or correct functionality of a sensor netw... more ABSTRACT Software reprogramming enables users to extend or correct functionality of a sensor network after deployment, preferably at a low cost. This paper investigates the improvement of energy efficiency and delay of reprogramming, at low resource cost. As enabling technologies data compression and incremental updates are used. Algorithms for both approaches are analyzed, as well as their combination, applied to resource-constrained devices. All algorithms are ported to the Contiki operating system, and profiled for different types of reprogramming. The presented results show that there is a clear trade-off between performance and resource requirements. Furthermore, the best reprogramming approach depends on the type of update. Experimentally, VCDIFF, or the combination of Lempel-Ziv-77/FastLZ for compression with BSDIFF for delta encoding, have been identified as the best possible options.
Improving the Performance of Trickle-Based Data Dissemination in Low-Power Networks
Lecture Notes in Computer Science, 2015
Procedia Computer Science, 2012
Reprogramming is an important issue in wireless sensor networks. It enables users to extend or co... more Reprogramming is an important issue in wireless sensor networks. It enables users to extend or correct functionality of a sensor network after deployment at a low cost. In this paper, we investigate the problem of improving energy efficiency and delay of reprogramming by using data compression and incremental updates. We analyze different algorithms for both approaches, as well as their combination, when applied to resource-constrained devices. Our results show that the classic Lempel-Ziv-77 compression algorithm with Bsdiff for delta encoding has the best overall performance compared to other compression algorithms; on average reducing energy usage by 74% and enabling 71% faster updates.
International Conference on Concurrency Theory, 2008
A well-known theorem in automata theory states that every context-free language is accepted by a ... more A well-known theorem in automata theory states that every context-free language is accepted by a pushdown automaton. We investigate this theorem in the setting of processes, using the rooted branching bisimulation and contrasimulation equivalences instead of language equivalence. In process theory, different from automata theory, interaction is explicit, so we realize a pushdown automaton as a regular process communicating with
Computing Research Repository, 2009
One of the main drawbacks while implementing the interaction between a plant and a supervisor, sy... more One of the main drawbacks while implementing the interaction between a plant and a supervisor, synthesised by the supervisory control theory of \citeauthor{RW:1987}, is the inexact synchronisation. \citeauthor{balemiphdt} was the first to consider this problem, and the solutions given in his PhD thesis were in the domain of automata theory. Our goal is to address the issue of inexact synchronisation
Analysis and Design of Hybrid Systems 2006, 2006
We analyze a control strategy for the pick-and-place module of a component mounting device. We us... more We analyze a control strategy for the pick-and-place module of a component mounting device. We use a combination of techniques from bondgraphtheory, systems theory, process algebra and differential algebra to achieve this, and we show how the hybrid process algebra HyPA aides us in combining these techniques and in using them on a common hybrid model of the device.
A new data flow analysis model for TDM
Proceedings of the tenth ACM international conference on Embedded software - EMSOFT '12, 2012
ABSTRACT This paper proposes a new data ow model for analyzing the worst-case temporal behavior o... more ABSTRACT This paper proposes a new data ow model for analyzing the worst-case temporal behavior of resource arbitration through Time Division Multiplexing (TDM). TDM arbitration allows resource sharing amongst the tasks of concurrent applications, where each application may have its own end-to-end hard real time requirements, such as minimum throughput and maximum latency. Current data flow modeling techniques for the temporal analysis of TDM arbitration over-estimate the worst-case temporal behavior of tasks. This causes unnecessary over-reservation of resources to the application, leading to under-utilization of system re- sources and unnecessary rejection of additional applications. We propose a conservative data ow model that accurately estimates the worst-case temporal behavior of TDM arbitration. Unlike existing models, we do not make restrictive assumptions on the characteristics of TDM, nor on the amount of resources reserved. This enables optimized resource allocation for TDM arbitration. We present a new model that closely mimicks the worst-case temporal behavior of TDM arbitration. We formally prove that this model is conservative with respect to the worst-case behavior of TDM arbitration, and we prove that it is strictly more accurate than the state-of-the-art. Quantitatively, we show that our new model leads to a 20% improvement of resource allocation, in a case study of a wireless LAN radio down-link.
On Bicontinuous Bisimulation and the Preservation of Stability
Lecture Notes in Computer Science, 2007
Cyclo-Static Data Flow Model for TDM
2014 14th International Conference on Application of Concurrency to System Design, 2014
Reconciling Urgency and Variable Abstraction in a Hybrid Compositional Setting
Lecture Notes in Computer Science, 2010
The extension of timed formalisms to a hybrid setting with urgency, has been carried out in a rat... more The extension of timed formalisms to a hybrid setting with urgency, has been carried out in a rather straightforward manner, seemingly without difficulty. However, in this paper, we show that the combination of urgency with abstraction from continuous variables leads to undesired behavior. Abstraction from continuous variables ultimately leads to a timed system again, but with a much richer set
Lecture Notes in Computer Science, 2011
CIF is a language designed for two purposes, namely as a specification language for hybrid system... more CIF is a language designed for two purposes, namely as a specification language for hybrid systems and as an interchange format for allowing model transformations between other languages for hybrid systems. To facilitate the top-down development of a hybrid system and also to be able to express models more succinctly in the CIF formalism, we need a mechanism for stepwise refinement. In this paper, we add the notion of hierarchy to a subset of the CIF language, which we call hCIF ⊂ . The semantic domain of the CIF formalism is a hybrid transition system, constructed using structural operational semantics. The goal of this paper is to present a semantics for hierarchy in such a way that only the SOS rules for atomic entities in hCIF ⊂ are redesigned in comparison to CIF . Furthermore, to be able to reuse existing tools like simulators of the CIF language, a procedure to eliminate hierarchy from an automaton is given.
Electronic Proceedings in Theoretical Computer Science, 2010
CIF is a language designed for two purposes, namely as a specification language for hybrid system... more CIF is a language designed for two purposes, namely as a specification language for hybrid systems and as an interchange format for allowing model transformations between other languages for hybrid systems. To facilitate the top-down development of a hybrid system and also to be able to express models more succinctly in the CIF formalism, we need a mechanism for stepwise refinement. In this paper, we add the notion of hierarchy to a subset of the CIF language, which we call hCIF ⊂ . The semantic domain of the CIF formalism is a hybrid transition system, constructed using structural operational semantics. The goal of this paper is to present a semantics for hierarchy in such a way that only the SOS rules for atomic entities in hCIF ⊂ are redesigned in comparison to CIF . Furthermore, to be able to reuse existing tools like simulators of the CIF language, a procedure to eliminate hierarchy from an automaton is given.
Analysis of Ethernet-Switch Traffic Shapers for In-Vehicle Networking Applications
Towards Budgeting in Real-Time Calculus: Deferrable Servers
Lecture Notes in Computer Science, 2007
Budgeting of resources is an often used solution for guaranteeing performance of lower priority t... more Budgeting of resources is an often used solution for guaranteeing performance of lower priority tasks. In this paper, we take a formal approach to the modeling of a deferrable server budgeting strategy, using real-time calculus. We prove a scheduling theorem for deferrable servers, and as a corollary show that an earlier claim of Davis and Burns, that periodic servers dominate
Two different lines of research are presented in the study of an industrially relevant problem of... more Two different lines of research are presented in the study of an industrially relevant problem of impact con- trol. One is focused on actual control of the process, while the other is focused on the development of a general lan- guage for modeling hybrid systems, of which the case study is an appropriate example.
Lecture Notes in Computer Science, 2010
Automata theory presents roughly three types of automata: finite automata, pushdown automata and ... more Automata theory presents roughly three types of automata: finite automata, pushdown automata and Turing machines. The automata are treated as language acceptors, and the expressiveness of the automata models are considered modulo language equivalence. This notion of equivalence is arguably too coarse to satisfactorily deal with a notion of interaction that is fundamental to contemporary computing. In this paper we therefore reconsider the automaton models from automata theory modulo branching bisimilarity, a well-known behavioral equivalence from process theory that has proved to be able to satisfactorily deal with interaction. We investigate to what extent some standard results from automata theory are still valid if branching bisimilarity is adopted as the preferred equivalence.
Electronic Proceedings in Theoretical Computer Science, 2010
The task of implementing a supervisory controller is non-trivial, even though different theories ... more The task of implementing a supervisory controller is non-trivial, even though different theories exist that allow automatic synthesis of these controllers in the form of automata. One of the reasons for this discord is due to the asynchronous interaction between a plant and its controller in implementations, whereas the existing supervisory control theories assume synchronous interaction. As a consequence the implementation suffer from the so-called inexact synchronisation problem. In this paper we address the issue of inexact synchronisation in a process algebraic setting, by solving a more general problem of refinement. We construct an asynchronous closed loop system by introducing a communication medium in a given synchronous closed loop system. Our goal is to find sufficient conditions under which a synchronous closed loop system is branching bisimilar to its corresponding asynchronous closed loop system.
The categorical limit of a sequence of dynamical systems
Electronic Proceedings in Theoretical Computer Science, 2013
Desynchronisablity of (partial) closed loop systems
Simulation of Drift Control for an Electron Microscope Stage Using Image Processing in the Loop
2013 IEEE International Conference on Pervasive Computing and Communications Workshops (PERCOM Workshops), 2013
ABSTRACT Software reprogramming enables users to extend or correct functionality of a sensor netw... more ABSTRACT Software reprogramming enables users to extend or correct functionality of a sensor network after deployment, preferably at a low cost. This paper investigates the improvement of energy efficiency and delay of reprogramming, at low resource cost. As enabling technologies data compression and incremental updates are used. Algorithms for both approaches are analyzed, as well as their combination, applied to resource-constrained devices. All algorithms are ported to the Contiki operating system, and profiled for different types of reprogramming. The presented results show that there is a clear trade-off between performance and resource requirements. Furthermore, the best reprogramming approach depends on the type of update. Experimentally, VCDIFF, or the combination of Lempel-Ziv-77/FastLZ for compression with BSDIFF for delta encoding, have been identified as the best possible options.
Improving the Performance of Trickle-Based Data Dissemination in Low-Power Networks
Lecture Notes in Computer Science, 2015
Procedia Computer Science, 2012
Reprogramming is an important issue in wireless sensor networks. It enables users to extend or co... more Reprogramming is an important issue in wireless sensor networks. It enables users to extend or correct functionality of a sensor network after deployment at a low cost. In this paper, we investigate the problem of improving energy efficiency and delay of reprogramming by using data compression and incremental updates. We analyze different algorithms for both approaches, as well as their combination, when applied to resource-constrained devices. Our results show that the classic Lempel-Ziv-77 compression algorithm with Bsdiff for delta encoding has the best overall performance compared to other compression algorithms; on average reducing energy usage by 74% and enabling 71% faster updates.
International Conference on Concurrency Theory, 2008
A well-known theorem in automata theory states that every context-free language is accepted by a ... more A well-known theorem in automata theory states that every context-free language is accepted by a pushdown automaton. We investigate this theorem in the setting of processes, using the rooted branching bisimulation and contrasimulation equivalences instead of language equivalence. In process theory, different from automata theory, interaction is explicit, so we realize a pushdown automaton as a regular process communicating with
Computing Research Repository, 2009
One of the main drawbacks while implementing the interaction between a plant and a supervisor, sy... more One of the main drawbacks while implementing the interaction between a plant and a supervisor, synthesised by the supervisory control theory of \citeauthor{RW:1987}, is the inexact synchronisation. \citeauthor{balemiphdt} was the first to consider this problem, and the solutions given in his PhD thesis were in the domain of automata theory. Our goal is to address the issue of inexact synchronisation
Analysis and Design of Hybrid Systems 2006, 2006
We analyze a control strategy for the pick-and-place module of a component mounting device. We us... more We analyze a control strategy for the pick-and-place module of a component mounting device. We use a combination of techniques from bondgraphtheory, systems theory, process algebra and differential algebra to achieve this, and we show how the hybrid process algebra HyPA aides us in combining these techniques and in using them on a common hybrid model of the device.
A new data flow analysis model for TDM
Proceedings of the tenth ACM international conference on Embedded software - EMSOFT '12, 2012
ABSTRACT This paper proposes a new data ow model for analyzing the worst-case temporal behavior o... more ABSTRACT This paper proposes a new data ow model for analyzing the worst-case temporal behavior of resource arbitration through Time Division Multiplexing (TDM). TDM arbitration allows resource sharing amongst the tasks of concurrent applications, where each application may have its own end-to-end hard real time requirements, such as minimum throughput and maximum latency. Current data flow modeling techniques for the temporal analysis of TDM arbitration over-estimate the worst-case temporal behavior of tasks. This causes unnecessary over-reservation of resources to the application, leading to under-utilization of system re- sources and unnecessary rejection of additional applications. We propose a conservative data ow model that accurately estimates the worst-case temporal behavior of TDM arbitration. Unlike existing models, we do not make restrictive assumptions on the characteristics of TDM, nor on the amount of resources reserved. This enables optimized resource allocation for TDM arbitration. We present a new model that closely mimicks the worst-case temporal behavior of TDM arbitration. We formally prove that this model is conservative with respect to the worst-case behavior of TDM arbitration, and we prove that it is strictly more accurate than the state-of-the-art. Quantitatively, we show that our new model leads to a 20% improvement of resource allocation, in a case study of a wireless LAN radio down-link.
On Bicontinuous Bisimulation and the Preservation of Stability
Lecture Notes in Computer Science, 2007
Cyclo-Static Data Flow Model for TDM
2014 14th International Conference on Application of Concurrency to System Design, 2014
Reconciling Urgency and Variable Abstraction in a Hybrid Compositional Setting
Lecture Notes in Computer Science, 2010
The extension of timed formalisms to a hybrid setting with urgency, has been carried out in a rat... more The extension of timed formalisms to a hybrid setting with urgency, has been carried out in a rather straightforward manner, seemingly without difficulty. However, in this paper, we show that the combination of urgency with abstraction from continuous variables leads to undesired behavior. Abstraction from continuous variables ultimately leads to a timed system again, but with a much richer set
Lecture Notes in Computer Science, 2011
CIF is a language designed for two purposes, namely as a specification language for hybrid system... more CIF is a language designed for two purposes, namely as a specification language for hybrid systems and as an interchange format for allowing model transformations between other languages for hybrid systems. To facilitate the top-down development of a hybrid system and also to be able to express models more succinctly in the CIF formalism, we need a mechanism for stepwise refinement. In this paper, we add the notion of hierarchy to a subset of the CIF language, which we call hCIF ⊂ . The semantic domain of the CIF formalism is a hybrid transition system, constructed using structural operational semantics. The goal of this paper is to present a semantics for hierarchy in such a way that only the SOS rules for atomic entities in hCIF ⊂ are redesigned in comparison to CIF . Furthermore, to be able to reuse existing tools like simulators of the CIF language, a procedure to eliminate hierarchy from an automaton is given.
Electronic Proceedings in Theoretical Computer Science, 2010
CIF is a language designed for two purposes, namely as a specification language for hybrid system... more CIF is a language designed for two purposes, namely as a specification language for hybrid systems and as an interchange format for allowing model transformations between other languages for hybrid systems. To facilitate the top-down development of a hybrid system and also to be able to express models more succinctly in the CIF formalism, we need a mechanism for stepwise refinement. In this paper, we add the notion of hierarchy to a subset of the CIF language, which we call hCIF ⊂ . The semantic domain of the CIF formalism is a hybrid transition system, constructed using structural operational semantics. The goal of this paper is to present a semantics for hierarchy in such a way that only the SOS rules for atomic entities in hCIF ⊂ are redesigned in comparison to CIF . Furthermore, to be able to reuse existing tools like simulators of the CIF language, a procedure to eliminate hierarchy from an automaton is given.