Middle managers networks

Data(base) zone The majority of monitoring and control takes place in this zone. It is a critical area for continuity and management of a control network. Operational support and engineering management systems are located in this zone. Naturally, huge data handling is involved with the help of data acquisition servers and historians. This zone is in the middle of corporate zone and control zone. Since there is a direct connection with the corporate zone it is a DMZ with firewalls on either side, as shown in Fig. XI/4.1.3-1. 

In a previous paper [6], we proposed a method for modeling the availability of middle/low pressure gas networks, which consists in an interleaved execution of i) a quasi-static fluid-dynamic analysis of the network and ) a stochastic model of the failure management procedure. The latter uses non-Markovian temporal parameters, thus overcoming the limits of memoryless and imbounded support of exponential distributions. As a distinctive trait, fluid-dynamic calculations are decoupled from the non-Markovian stochastic analysis and the complexity of stochastic analysis is insensitive to topology and size of the gas network. 

---