Quotient models of a category up to directed homotopy.
Relative directed homotopy theory of partially ordered spaces.
Reparametrizations of continuous paths.
Selfgenerating sequences and different types of computational devices [Abstract of thesis]
Semi-commutations and partial commutations
Semi-commutations and Partial commutations
The aim of this paper is to show that a semi-commutation function can be expressed as the compound of a sequential transformation, a partial commutation function, and the reverse transformation. Moreover, we give a necessary and sufficient condition for the image of a regular language to be computed by the compound of two sequential functions and a partial commutation function.
Some geometric perspectives in concurrency theory.
Special Issue: AAMP VIII AND ISCAMI 2011
Structured redundancy for fault tolerance in state-space models and Petri nets
The design and implementation of systems in state form has traditionally focused on minimal representations which require the least number of state variables. However, “structured redundancy” – redundancy that has been intentionally introduced in some systematic way – can be extremely important when fault tolerance is desired. The redundancy can be used to detect and correct errors or to guarantee desirable performance despite hardware or computational failures. Modular redundancy, the traditional...
Supervisory controller design for timed-place Petri nets
Supervisory controller design to avoid deadlock in discrete-event systems modeled by timed-place Petri nets (TPPNs) is considered. The recently introduced approach of place-stretching is utilized for this purpose. In this approach, given an original TPPN (OPN), a new TPPN, called the place-stretched Petri net (PSPN), is obtained. The PSPN has the property that its marking vector is sufficient to represent its state. By using this property, a supervisory controller design approach for TPPNs to avoid...
-homotopy and refinement of observation. II: Adding new -homotopy equivalences.
The branching nerve of HDA and the Kan condition.
The Formalization of Decision-Free Petri Net
In this article we formalize the definition of Decision-Free Petri Net (DFPN) presented in [19]. Then we formalize the concept of directed path and directed circuit nets in Petri nets to prove properties of DFPN. We also present the definition of firing transitions and transition sequences with natural numbers marking that always check whether transition is enabled or not and after firing it only removes the available tokens (i.e., it does not remove from zero number of tokens). At the end of this...
The shape of a category up to directed homotopy.
T-homotopy and refinement of observation. III. Invariance of the branching and merging homologies.
T-homotopy and refinement of observation. IV. Invariance of the underlying homotopy type.
Thread algebra for noninterference
Thread algebra is a semantics for recent object-oriented programming languages [J.A. Bergstra and M.E. Loots, J. Logic Algebr. Program. 51 (2002) 125–156; J.A. Bergstra and C.A. Middelburg, Formal Aspects Comput. (2007)] such as C# and Java. This paper shows that thread algebra provides a process-algebraic framework for reasoning about and classifying various standard notions of noninterference, an important property in secure information flow. We will take the noninterference property given by...
Thread algebra for noninterference
Thread algebra is a semantics for recent object-oriented programming languages [J.A. Bergstra and M.E. Loots, J. Logic Algebr. Program.51 (2002) 125–156; J.A. Bergstra and C.A. Middelburg, Formal Aspects Comput. (2007)] such as C# and Java. This paper shows that thread algebra provides a process-algebraic framework for reasoning about and classifying various standard notions of noninterference, an important property in secure information flow. We will take the noninterference property given...
Time Petri nets state space reduction using dynamic programming
Timed Petri-net based formulation and an algorithm for the optimal scheduling of batch plants
The effective scheduling of operations in batch plants has a great potential for high economic returns, in which the formulation and an optimal solution algorithm are the main issues of study. Petri nets have proven to be a promising technique for solving many difficult problems associated with the modelling, formal analysis, design and coordination control of discrete-event systems. One of the major advantages of using a Petri-net model is that the same model can be used for the analysis of behavioural...