Modeling the Exogenous Coordination of Mobile Channel-based Systems with Petri Nets

In this paper, we discuss how to model systems that communicate through and are coordinated by mobile channels. Mainly, we focus on modeling the exogenous coordination behavior imposed by these channels. We use Petri Nets as our modeling language, for they provide a graphically and mathematically founded modeling formalism. We give Petri Nets for a set of mobile channel types. This allows us to construct models of applications, by taking the Petri Net of each component and each mobile channel, and composing them together. For this purpose, we define a special Petri Net composition function. We also discuss analysis and simulation of these models and their exogenous coordination behavior.     

Phase,microstructural investigation and thermoelectric properties of Ga-doped zinc oxide-based ceramics sintered under an argon atmosphere

Compositions in the (Zn_0.98-yAl_0.02Ga_y)O (y?=?0.00, 0.01, 0.02, 0.03) series were fabricated via the conventional solid-state sintering route under an argon atmosphere, and their phase, microstructure and thermoelectric properties were investigated. Single-phase ceramics were formed for the compositions with y?≤?0.01. However, an unknown secondary phase was developed along with the parent phases when y?≥?0.02 due to an over solubility limit of Ga in Zn. For a particular value of Ga substitution for Zn, the (Zn_0.98Al_0.02)O ceramics had decreased electrical resistivity (ρ) and an increased power factor (PF). In the present study, the highest power factor of 5.518?×?10^?4 W?K^?2 m^?1 and lowest electrical resistivity of ~0.82 mΩcm were obtained for the composition with y?=?0.01, i.e., (Zn_0.97Al_0.02Ga_0.01)O.     

The GKS Input Model in Manifold

This paper describes the specification of the GKS input model in M anifold . The aim of the work reported in this paper was two-fold: first, to review the communication patterns implied by the GKS input model, and second, to evaluate the suitability of the M anifold language as a tool for defining complex dynamic interaction patterns that are common in non-trivial user interfaces.
The GKS input model is also adopted by all more recent ISO graphics standard documents. A more formal scrutiny of the inter-communication of the components of this model, excluding the implementation details of their functionality, is instructive in itself. It can reveal directions for improvement of its shortcomings and for generalization of its strengths for the ongoing effort to define the functionality of future graphics packages.
M anifold is a language for describing inter-process communications. Processes in M anifold communicate by means of buffered communication links called streams and by reacting to events raised asynchronously by other processes. Our experience shows that M anifold is a promising tool for describing systems of cooperating parallel processes. Our M anifold specification of the GKS input model offers a very flexible way to structure user defined logical input devices. Furthermore, it is simple and modular enough to allow easy extensions to include more functionality by local modifications. As such, it can serve as a basis for possible extensions and enhancements envisioned for future graphics packages.
1987 CR Categories: C.1.2, C.1.3, C.2.m, D.1.3, F.1.2, I.1.3, I.3.6, I.3.4.
1885 Mathematical Subject Classification: 68N99, 68Q10,68U05.     

Models and temporal logical specifications for timed component connectors

Component-based software engineering advocates construction of software systems through composition of coordinated autonomous components. Significant benefits of this approach include software reuse, simpler and faster construction, enhanced reliability, and dramatic reductions in the complexity of construction of provably correct critical systems, many of which involve real-time concerns. Effective, flexible component composition by itself still poses a challenge today and yet the special nature of real-time constraints makes component-based construction of real-time systems even more demanding. The coordination language Reo supports compositional system construction through connectors that exogenously coordinate the interactions among the constituent components which unawarely comprise a complex system, into a coherent collaboration. The simple, yet surprisingly rich, calculus of channel composition that underlies Reo offers a flexible framework for compositional construction of coordinating component connectors with real-time properties. In this paper, we present an operational semantics for the channel-based component connectors of Reo in terms of Timed Constraint Automata and introduce a temporal-logic for specification and verification of their real-time properties.