As low-power wide-area network (LPWAN) end devices (EDs) are deployed in massive scale, their economic and environmental costs of operation are becoming too significant to ignore and too difficult to estimate. While LPWAN architectures and protocols are designed to primarily save energy, this study shows that energy saving does not necessarily lead to lower cost or environmental footprint of the network. Accordingly, a theoretical framework is proposed to estimate the operational expenditure (OpEx) and environmental footprint of LPWAN EDs. An extended constrained optimization model is provided for the ED link assignment to gateways (GWs) based on heterogeneous ED configurations and hardware specifications. Based on the models, a simulation framework is developed which demonstrates that OpEx, energy consumption, and environmental footprint can be in conflict with each other as constrained optimization objectives. We demonstrate different ways to achieve compromises in each dimension for overall improved network performance.
Protocols engineering of IP/MPLS networks are constantly improving with new separated features and new resilience mechanisms. In the transportation of audiovisual signals domain we must compose with multicast protocols which are designed from other scientific developments. This audiovisual traffic due to his non springy nature presents a very huge sensitivity to network recovery after a failure and these effects can be amplified by end devices (encoding, decoding and MPEG IP encapsulation). In this way when we choose between engineering solutions the unique criterion of availability is not enough, we must complete by an impact analysis on the service made by the network resilience technics. In this paper, we propose a first approach to analyze the behavior of different protocols engineering to improve selection. We propose using Bayesian networks to compare performance on different criteria and we will illustrate with two engineering models. The results focus on a real improvement of availability by choosing the adapted engineering solution.
The Climate Group notes that energy consumption by ICT activities represented 2 % of global human activity in 2009 [1]. ICT is therefore a sector contributing both to natural resource depletion and to greenhouse gas emission. Moreover, ICT generates considerable quantities of electronic waste, it emits radio waves (including GSM and WiFi) that can adversely affect human and animal health, and it can have an impact on the natural beauty of the landscape (e.g. antennas). A new challenge for ICT engineers is therefore to be able to design ICT more efficiently by considering environmental constraints. In the ecology domain, J. M. Benyus' book "Biomimicry" [2] proposed ten commandments for mature ecosystems. The objective of this paper is to apply these commandments to ICT, by focusing on green network architecture design. The main developments in this research are the proposed relationships between the ten commandments and the networking domain and metrics for assessing both the project-system and the system-of-interest when designing green network architectures.
In this paper we propose a distributed control system based on FIP fieldbus. It is applied to machine-tool as a replacement for the traditional CNC (Computerized Numerical Controller). The system is composed of a set of microprocessor-based modules (PCs, motion controllers, I/Os, ...) interconnected by FLP real-time network. The main idea is to enable each module to be intelligent, improving thus the jlexibility and the fault tolerant capability of the whole system. Each module being a sub-control system, accomplishes its own control task, some of them for motion control and others for evaluating sensors and regulating actuators. The communication (information exchanges and synchronization) among these modules is ensured by FP. This system allows both task distribution as well as equipment topological distribution. We discuss some distribution criteria and describe an experimental implementation.
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