The old electricity network infrastructure has proven to be inadequate, with respect to modern challenges such as alternative energy sources, electricity demand and energy saving policies. Moreover, Information and Communication Technologies (ICT) seem to have reached an adequate level of reliability and flexibility in order to support a new concept of electricity network-the smart grid. In this work, we will analyse the state-of-the-art of smart grids, in their technical, management, security, and optimization aspects. We will also provide a brief overview of the regulatory aspects involved in the development of a smart grid, mainly from the viewpoint of the European Union.

Abstract-Context. Mobile web apps represent a large share of the Internet today. However, they still lag behind native apps in terms of user experience. Progressive Web Apps (PWAs) are a new technology introduced by Google that aims at bridging this gap, with a set of APIs known as service workers at its core. Goal. In this paper, we present an empirical study that evaluates the impact of service workers on the energy efficiency of PWAs, when operating in different network conditions on two different generations of mobile devices. Method. We designed an empirical experiment with two main factors: the use of service workers and the type of network available (2G or WiFi). We performed the experiment by running a total of 7 PWAs on two devices (an LG G2 and a Nexus 6P) that we evaluated as blocking factor. Our response variable is the energy consumption of the devices. Results. Our results show that service workers do not have a significant impact over the energy consumption of the two devices, regardless of the network conditions. Also, no interaction was detected between the two factors. However, some patterns in the data show different behaviors among PWAs. Conclusions. This paper represents a first empirical investigation on PWAs. Our results show that the PWA and service workers technology is promising in terms of energy efficiency.

Background. Energy efficiency is an increasingly important property of software. A large number of empirical studies have been conducted on the topic. However, current state-of-the-Art does not provide empiricallyvalidated guidelines for developing energy-efficient software. Aim. This study aims at assessing the impact, in terms of energy savings, of best practices for achieving software energy efficiency, elicited from previous work. By doing so, it identifies which resources are affected by the practices and the possible trade-offs with energy consumption. Method. We performed an empirical experiment in a controlled environment, where we applied two different Green Software practices to two software applications, namely query optimization in MySQL Server and usage of "sleep" instruction in the Apache web server. We then performed a comparison of the energy consumption at system-level and at resource-level, before and after applying the practice. Results. Our results show that both practices are effective in improving software energy efficiency, reducing consumption up to 25%. We observe that after applying the practices, resource usage is more energy-proportional i.e. increasing CPU usage increases energy consumption in an almost linear way. We also provide our reflections on empirical experimentation in software energy efficiency. Conclusions. Our contribution shows that significant improvements in software energy efficiency can be gained by applying best practices during design * Corresponding author Email addresses: g.procaccianti@vu.nl (Giuseppe Procaccianti), hector.fernandez@vu.nl (Hector Fernandez), p.lago@vu.nl (Patricia Lago)Preprint accepted for publication in Journal of Systems and Software February 24, 2016 and development. Future work will be devoted to further validate best practices, and to improve their reusability.

Cloud-based software architectures introduce more complexity and require new competences for migration, maintenance, and evolution. Although cloud computing is often considered as an energy-efficient technology, the implications of cloud-based software on energy efficiency lack scientific evidence. At the same time, energy efficiency is becoming a crucial requirement for cloud service provisioning, as energy costs significantly contribute to the Total Cost of Ownership (TCO) of a data center. In this paper, we present the results of a systematic literature review that investigates cloud software architectures addressing energy efficiency as a primary concern. The aim is to provide an analysis of the state-of-the-art in the field of energy-efficient software architectures.

Software energy efficiency is a research topic where experimentation is widely adopted. Nevertheless, current studies and research approaches struggle to find generalizable findings that can be used to build a consistent knowledge base for energyefficient software. To this end, we will discuss how to combine the traditional hypothesis-driven (top-down) approach with a bottom-up discovery approach. In this technical briefing, participants will learn the challenges that characterize the research in software energy efficiency. They will experience the complexity in this field and its implications for experimentation.