Abstract
This paper addresses the dynamic stability analysis of an islanded power system regarding the installation of a reversible hydro power plant for increasing renewable energy integration. Being a high-head facility, the hydro power plant consists of separated pumps and turbines (Pelton type). In order to properly support the identification of hydro pumps connection requirements and the technology to be used, different options were taken into consideration, namely: fixed speed pumps coupled to induction machines directly connected to the grid and adjustable speed pumps supplied by a drive system. Extensive numerical simulations of the power system's dynamic behaviour response allowed the evaluation of the hydro power plant's role for the purpose of grid stability conditions. These simulations showed that the high head hydro power installation provides a marginal contribution to system frequency regulation when explored in turbine operation mode, leading to a reversible power station with a single penstock. Moreover, due to the significant additional system load introduced by the hydro pumping units, the obtained results clearly indicate that supplementary regulation flexibility is required to attend the need of assuring the stable operation of the system in case of critical disturbances such as grid faults. The study case demonstrates that, although the foreseen operation of a reversible hydro power plant creates new security challenges to overcome in an autonomous power system, robust technical solutions can be identified without increasing, from the local system operator's perspective, the operation complexity of the power system.

Abstract
This article is about making decisions concerning the management of sustainability, decisions that may influence the use or protection of natural resources or address difficult societal choices. Managers have more and more to tackle a diversity of problems in a rigorous and transparent way. One of the distinctive features of these decisions is that managers must give attention to both the values of people affected and factual information concerning the potential consequences of actions. This imposes the adoption of new methods for structuring spaces, strategy alternatives, and organizational planning. The support from operational research analysts becomes increasingly important, as we are dealing with people mostly without strong quantitative or model-building backgrounds. With the presence of different perspectives and mental models, behavior elements are at the core of the problem and unintentional biases in model use may occur. Our intention is to help promote the transference of knowledge to and within companies so that they may assure resilience. We found in general morphological analysis a great help for that. We want to make available a meta-model based on Operational Research for fields involving public resources and multiple interests to aid current and future managers of companies. We conclude the article with two case studies to illustrate our approach.

Abstract
The increasing capabilities of smartphones is paving way to novel applications through the crowd-sourcing of these untapped resources, to form hyperlocal meshes commonly known as edge-clouds. While a relevant body-of-work is already available for the underlying networking, computing and storage facilities, security and privacy remain second class citizens. In this paper we present Panoptic, an edge-cloud system that enables the search for missing people, similar to the commonly known Amber alert system, in high density scenarios where wireless infrastructure might be limited (WiFi and LTE), e.g. concerts, while featuring privacy and security by design. Since the limited resources present in the mobile devices, namely battery capacity, Panoptic offers a computing offloading that tries to minimize data leakage while offering acceptable levels of performance. Our results show that it is achievable to run these algorithms in an edge-cloud configuration and that it is beneficial to use this architecture to lower data transfer through the wireless infrastructure while enforcing privacy. Results from our experimental evaluation show that the security layer does not impose a significant overhead, and only accounts for 2% of the total execution time for an edge cloud comprised by, but not limited to, 8 devices.

Abstract

Abstract
This paper presents an extensive analysis in relation to transforming electric distribution networks in order to accommodate large quantities of variable renewable energy sources (vRESs). For this purpose, a multi-stage and stochastic mixed integer linear programming (S-MILP) model is employed. The algebraic model developed optimally allocates energy storage systems (ESSs) along with an optimal dynamic distribution network switching. For the analysis, a standard IEEE 119-bus distribution network system was used as a case study. Test results reveal that the joint optimization of ESSs and network reconfiguration markedly increase flexibility in existing systems, leading to an increase in the levels of renewables integration and utilization. Moreover, the analysis of the results shows the prospect of such systems in going fully "carbonfree", i.e. with vRES power entirely meeting system demand. Generally, the current work demonstrates that a more effective integration and utilization of large-scale vRESs is possible when existing systems are equipped with enabling technologies that are already commercially available.

Abstract
Manaus, a city of more than two million people, suffers problems arising from strong sunlight and aggravated by several factors, such as traffic congestion and greenhouse gas emissions generated by evaporation and burning of fuel. The present study examined Carbon Monoxide (CO) and Nitrogen Dioxide (NO2) emissions in an urban area of the city using different methodologies. CO and NO2 were measured using automated and passive analyzers, respectively. Meanwhile, direct monitoring of these pollutants was performed in vehicular sources in the vicinity of sampling locations. Results showed that levels of carbon monoxide vary over time, being higher during peak movement of vehicles. NO2 values have exceeded the recommendations of the World Health Organization (WHO), and monitoring at source showed high levels of CO and NO2 emissions to the atmosphere.