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The power management of ICT systems, that is, data processing (Dp) and telecommunication (Tlc) systems, is becoming a relevant problem in economical terms. Dp systems totalize millions of servers and associated subsystems (processors, monitors, storage devices, etc.) all over the world that need to be electrically powered. Dp systems are also used in the government of Tlc systems, which, besides requiring Dp electrical power, also require Tlc-specific power, both for mobile networks (with their cell-phone towers and associated subsystems: base stations, subscriber stations, switching nodes, etc.) and for wired networks (with their routers, gateways, switches, etc.). ICT research is thus expected to investigate into methods to reduce Dp- and Tlc-specific power consumption. However, saving power may turn into waste of performance, in other words, into waste of ICT quality of service (QoS). This paper investigates the Dp and Tlc power management policies that look at compromises between power saving and QoS.

The development of a distributed simulator requires knowledge and skills that might be unavailable or difficult to acquire. Bringing model-driven approaches to the development of distributed simulators contributes to reduce both the need for specific skills and the development effort. To support this innovative development methodology, we introduce a layered simulation architecture named SimArch that allows to define simulation models that can be transparently transformed into simulation programs ready to be executed in a distributed (or local) mode.SimArch defines layers of services at increasing levels of abstraction on top of the execution environment, thus allowing developers to build distributed simulators without explicit knowledge about the execution environment (local/distributed) and the specific distributed simulation infrastructure (e.g., HLA).In order to show the effectiveness of the proposed approach, SimArch has been provided with an Extended Queueing Network (EQN) simulation language, which has been applied to the development of an example distributed simulator in the computer network domain.