Abstract
The integration between industrial applications and industrial networks technologies is a required condition to share information at the factory level. Industrial networks are known for having different communication protocols. Therefore wired gateway technologies play an important role in the integration of different protocol stacks, wherever that integration is necessary. However, if there are physical constraints that make hard setting up a wired gateway, such as, difficult access for the required cabling, the use of a wireless gateway may present both a technical and an economical advantage when compared with wired gateway. This paper illustrates two industrial automation case studies, where both solutions use ELPRO wireless gateways proposed by Tee Wise Company (R). The assessment results confirm that the use of wireless gateways may be an interesting solution for the industrial communication interconnection being analyzed. In this paper, we make a technical and economical assessment of the use of wireless gateways in industrial networks as a contributive solution for the integration of different industrial communication protocols.

Abstract
WirelessHART currently appears as a promising solution for the last mile connection in process control applications. Most of these applications have stringent dependability requirements, where a system failure may result in economic losses, or damage for human life or the environment. Among the different type of faults that can lead to a system failure, permanent faults on network devices have a major impact. They can hamper communication over long periods of time and consequently they may disturb, or even disable, control algorithms with all resulting problems. In this work we perform a dependability evaluation of the best practices indicated by the HART Communication Foundation (HCF), when network devices are subject to permanent faults.

Abstract
In this paper we make a comparative assessment between the RT-WiFi and HCCA approaches to handle real-time traffic in IEEE 802.11 networks operating in open communication environments. The main focus will be on the assessment of the admission control mechanism proposed for the RT-WiFi upper layer, that is based on a non-preemptive EDF scheduling algorithm combined with a mechanism that measures the blockage times on medium access of real-time stations due to retransmissions and delays. The goal is to achieve a good compromise between medium utilization and timeliness. This proposal is compared with HCCA, and the results show that RT-WiFi offers a significantly better behavior in what concerns the maximum number of admitted streams.

Abstract
WirelessHART currently appears as a leading solution for interconnection of wireless devices in industrial process control applications. However, the lack of knowledge about the influence of transient faults in WirelessHART networks can lead to the choice of less reliable topologies. In this work,we propose a simulation model to evaluate WirelessHART networks in the presence of transient faults. We assume that these faults result from noisy environments that disturb communications between devices. The model was developed using the Stochastic Petri Net (SPN) formalism, supported by the Mobius tool. For further developments, we target the development of an application that automates the assessment of a WirelessHART network in transient fault scenarios.

Abstract
In this paper, we propose a TDMA-based communication approach to be used upon the EDCA communication mechanism defined in the IEEE 802.11e standard. This approach allows the coexistence of realtime (RT) traffic together with uncontrolled (external) traffic sources. In the context of this paper, RT traffic means small sized packets generated in periodic intervals, which must be delivered before the end of the message stream period. The target of this paper is to highlight some limitations of the EDCA mechanism when supporting RT communication and to compare these results with those obtained with the proposed TDMA approach. We have assessed these two mechanisms considering an open communication environment, where there are RT and non-RT stations operating in the same frequency band. Furthermore, a realistic error-prone model channel was used to measure the impact of interferences against an error-free channel. We show that the proposed TDMA approach offers an almost constant access delay and it also improves the EDCA behavior in what concerns the average functional throughput and the average deadline losses.

Abstract
The paper proposes a simulation model which enables the evaluation of IEEE 802.11e EDCA networks, focusing in the behavior of the Enhanced Distributed Channel Access (EDCA) function associated to Quality of Service (QoS) stations. When compared with currently used simulation models, the proposed model provides a more accurate implementation of some aspects (timeouts, EIFS), a flexible implementation, and an easiness of use. Besides, a large number of different types of performance measures can be obtained. The model is based on a high level Stochastic Petri Net formalism referred as Stochastic Activity Networks (SAN), able to produce very compact and efficient models, and which is supported by the Mobius tool.