Deadlock prevention is a crucial step in the modeling of flexible manufacturing systems. In Petri net framework, deadlock policies based on siphon control are often employed, since it easy to specify generalized mutual exclusion constraints that avoid emptying siphons. However, such may require an excessive computational load and result impractical oversized subnets. This consequence redundancy conditions derived from this paper, novel method proposed provides small size controllers, set...

In Petri-net (PN) modeling of flexible manufacturing systems, deadlock prevention is often addressed by means siphon-control methods. Constraints that avoid the emptying siphons can be easily implemented using additional places suitably connected to PN transitions. Efficient siphon-based techniques achieve highly permissive solutions as few control possible. One such technique employs a set-covering approach optimally match emptiable critical markings. this paper, modified version method...

The paper addresses the problem of enumerating minimal siphons in an ordinary Petri net. algorithms developed this work recursively use a partitioning procedure to reduce original search multiple simpler subproblems. Each subproblem has specific additional place constraints with respect problem. Some results on algorithm correctness, convergence, and computational complexity are provided, as well experimental evaluation performance. can be applied enumerate minimal, place-minimal siphons, or...

This paper proposes a new model for the partitioning and scheduling of specification on partially dynamically reconfigurable hardware. Although this problem can be solved optimally only by tackling its subproblems jointly, exceeding complexity such task leads to decomposition into two phases. The phase is based graph-theoretic approach, which aims obtain near optimality even if performed independently from subsequent phase. For phase, integer linear programming formulation heuristic approach...

Most approaches for deadlock prevention and liveness enforcement in Petri nets rely on siphon control methods or the theory of regions to derive monitor-based supervisors. These techniques raise methodological computational issues, from existence feasible solutions hardness guaranteeing maximal permissivity optimality size cost subnet. Recently, supervisor design problem has also been reformulated as a direct monitor optimization task based integer linear programming, which can more...

A recent line of work has sought the implementation maximally permissive deadlock avoidance policy (DAP) for a broad class complex resource allocation systems (RAS) as classifier that gives effective and parsimonious representation to dichotomy underlying behavioral space into admissible inadmissible subspaces defined by policy. The presented in this paper complements past developments area providing 1) succinct conditions regarding possibility expressing aforementioned set linear...

We have performed 75-ns molecular dynamics (MD) simulations of aqueous solutions a 26-unit NIPAAm oligomer at two temperatures, 302 and 315 K, below above the experimentally determined lower critical solution temperature (LCST) p(NIPAAm). been able to show that K assumes compact form, while it keeps more extended form K. A similar behavior has demonstrated for oligomer, where units had substituted by methacryloyl-l-valine (MAVA) comonomers, one them being charged neutral. For another...

In this paper, we propose an algorithm for the measure of local and global contrast in digital images. It applies locally, at various sub-sampled levels, a simplified computation based on DOG finally it recombines all values to obtain measure. The proposed method comes from modification previous with different parameterized way recombine color channels. As new approach idea recombining channels following measures taken image itself. Preliminary tests results are presented discussed.

A novel framework is introduced for the supervisory control (SC) of timed discrete event systems based on Time Petri nets. The method encompasses both logical (markings to reach or avoid) and temporal specifications (arrival departure times in specific markings). It relies construction a partial forward reachability graph modified state class type formulation integer linear programming problems establish suitable firing time intervals (FTIs) controllable transitions. For each enabled...

Deadlock Prevention and Liveness Enforcement in Petri nets are mostly addressed with monitor-based methods, designed indirectly using the concept of siphon or theory regions. The obtained control solutions sometimes maximally permissive, but generally not optimal terms number monitors, nor cost subnet. This paper proposes an optimization approach aiming at direct design that allows for easy formalization various objectives. An efficient solution scheme, based on a branch-and-bound is also...

Retinex theory estimates the human color sensation at any observed point by correcting its based on spatial arrangement of colors in proximate regions. We revise two recent path-based, edge-aware implementations: Termite (TR) and Energy-driven (ETR). As original implementation, TR ETR scan neighborhood image pixel paths rescale their chromatic intensities intensity levels computed reworking pixels paths. Our interest is due to unique, content-based scanning scheme, which uses edges define...