Exponential convergence under distributed averaging integral frequency control

We investigate the performance and robustness of distributed averaging integral controllers used in the optimal frequency regulation of power networks. We construct a strict Lyapunov function that allows us to quantify the exponential convergence rate of the closed-loop system. As an application, we study the stability of the system in the presence of disruptions to the controllers' communication network, and investigate how the convergence rate is affected by these disruptions. (C) 2018 Elsevier Ltd. All rights reserved

ESTABLISHMENT OF THE SECOND LIST OF UNION PROJECTS OF COMMON INTEREST: EVALUATION OF CANDIDATE PROJECTS OF COMMON INTEREST IN THE FIELD OF SMART GRIDS

The document presents the outcome of the evaluation process of candidate Projects of Common Interest in the area of Smart Grids, under the trans-European energy infrastructure regulation. The evaluation follows the guidelines of the assessment framework for Smart Grid projects, developed by the JRC within the EC Smart Grid Task Force.JRC.F.3-Energy Security, Systems and Marke

Quantitative dependability and interdependency models for large-scale cyber-physical systems

Cyber-physical systems link cyber infrastructure with physical processes through an integrated network of physical components, sensors, actuators, and computers that are interconnected by communication links. Modern critical infrastructures such as smart grids, intelligent water distribution networks, and intelligent transportation systems are prominent examples of cyber-physical systems. Developed countries are entirely reliant on these critical infrastructures, hence the need for rigorous assessment of the trustworthiness of these systems. The objective of this research is quantitative modeling of dependability attributes -- including reliability and survivability -- of cyber-physical systems, with domain-specific case studies on smart grids and intelligent water distribution networks. To this end, we make the following research contributions: i) quantifying, in terms of loss of reliability and survivability, the effect of introducing computing and communication technologies; and ii) identifying and quantifying interdependencies in cyber-physical systems and investigating their effect on fault propagation paths and degradation of dependability attributes. Our proposed approach relies on observation of system behavior in response to disruptive events. We utilize a Markovian technique to formalize a unified reliability model. For survivability evaluation, we capture temporal changes to a service index chosen to represent the extent of functionality retained. In modeling of interdependency, we apply correlation and causation analyses to identify links and use graph-theoretical metrics for quantifying them. The metrics and models we propose can be instrumental in guiding investments in fortification of and failure mitigation for critical infrastructures. To verify the success of our proposed approach in meeting these goals, we introduce a failure prediction tool capable of identifying system components that are prone to failure as a result of a specific disruptive event. Our prediction tool can enable timely preventative actions and mitigate the consequences of accidental failures and malicious attacks --Abstract, page iii

Quantifying riverine macroinvertebrate community responses to water resource management operations

Water resource management operations have significantly modified river flow regimes globally, prompting widespread lotic ecosystem responses. There is a growing need to better understand how increasingly prevalent hydrological alterations to riverine systems will affect biota dependent on specific elements of river flow regimes. This thesis examines macroinvertebrate community responses to river flow regimes modified by various water resource management operations across southwest England though four detailed investigations. The first study examines the influence of river impoundments and how macroinvertebrate communities differ between regulated and non-regulated sections of river. Findings from this investigation highlight that flow regulation alters the structure and function of faunal assemblages due to significant changes to the flow regime, rather than stream temperature modifications associated with the reservoirs. The second study focusses on groundwater dominated headwater streams transitioning from temporary (i.e. reaches periodically drying positioned furthest upstream) to perennial flow conditions which are subjected to variable groundwater abstraction intensities. The results indicate that macroinvertebrate communities respond significantly to the duration of antecedent flowing conditions and the spatial proximity of sampling sites to perennial sources; but faunal assemblages are not sensitive to groundwater abstraction. The third study examines how communities inhabiting different organic and mineralogical lotic habitats responded to multiple river flow properties (hydrological indices, anthropogenic flow alteration measures and hydraulic variables) in perennial, groundwater dominated systems. The findings highlight that faunal assemblages are most responsive to local hydraulic conditions measured at the point of sampling, rather than antecedent hydrological conditions. The influence of hydraulic properties on communities differs between lotic habitats, highlighting that mineralogical and organic characteristics of riverbeds strongly mediate how biota respond to flow. The final study presents the results of a long-term (1995-2016), region-wide (spanning Dorset, Hampshire and Wiltshire) examination of macroinvertebrate communities inhabiting groundwater dominated rivers and their responses to hydrological variability (including extreme low- and high-flow events) and anthropogenic flow alterations. The results indicate that indices characterising the proportion of discharge added to (through effluent water returns and low-flow alleviation strategies) or removed from the river (via groundwater abstraction) exert profound effects on faunal assemblages over long-term periods. These results provide empirical evidence that reductions in river discharges via groundwater abstraction of approximately 15% have no perceptible negative ecological effects on macroinvertebrate communities. The results from the four detailed investigations are used to develop conceptual models to illustrate how research undertaken within this thesis can be applied more widely. The findings and study designs presented within this thesis could inform surface and groundwater water resource management operations and underpin the development of environmental flow methodologies required to conserve riverine ecosystems globally

An Assessment of PIER Electric Grid Research 2003-2014 White Paper

This white paper describes the circumstances in California around the turn of the 21st century that led the California Energy Commission (CEC) to direct additional Public Interest Energy Research funds to address critical electric grid issues, especially those arising from integrating high penetrations of variable renewable generation with the electric grid. It contains an assessment of the beneficial science and technology advances of the resultant portfolio of electric grid research projects administered under the direction of the CEC by a competitively selected contractor, the University of California’s California Institute for Energy and the Environment, from 2003-2014

Energy security: a review of studies of the economic value of energy security

Il lavoro tenta di chiarire il concetto di sicurezza energetica individuandone gli aspetti fondamentali.Inoltre vengono analizzati e discussi criticamente i modelli proposti precendentemente per la quantificazione del livello di sicurezza.Infine vengono elencate quali dovrebbero essere le metriche realmente efficaci da utilizzare nella costruzione di modello e chiarito come quest'ultimi andrebbero usati per essere significativ

Climate change adaptation in industry and business

This report delivers a best practice framework to integrate financial risk assessment, governance and disclosure with existing governance principles around climate change adaptation.AbstractThe Australian business community has long been aware of the risks and opportunities associated with greenhouse gas mitigation and climate change policies. Some businesses have taken initial steps to adapt to the expected effects of climate change; however, most enterprises are only vaguely aware of the breadth of adaptation that may be required. Associated with strategic adaptation are the principles of financial/operational risk management and governance, as well as financial impact disclosure to investors and regulators. We develop a consolidated framework in which boards and executive managers can develop a robust approach to climate change adaptation governance, climate change risk assessment and financial disclosure. The project outlines a matrix of disclosures required for investors to enable them to evaluate corporate exposure to climate change risk.The project initially comprised a set of workshops with members of the Australian business community, industry representatives, regulatory authorities and academics with expertise in business risk and disclosure effects. Each workshop focused on a separate theme that built upon the work of previous workshops. A set of follow-up discussions was held with some of the key members who contributed to the project, including the Australian Stock Exchange (ASX) Investor Group on Climate Change (IGCC), the Australian Accounting Standards Board (AASB) and the Australian Institute of Company Directors. This discussion permitted each body to comment on the final report, advise on the mechanics of the costing, reporting and disclosure approaches of climate change adaptation, and lend their expertise to the formulation of an appropriate framework.The scope of the research is constrained to firm behaviour and the requirements for investor disclosure and governance of adaptation activities. The project therefore focuses on financial analyses – including real options – undertaken by firms with regard to investing in climate change adaptation activities and projects. While the economic costs and benefits are important to organisational adaptation activities, they represent a secondary level of analysis that may need to be carried out on either an independent or cumulative scale by governments or other bodies to measure the wider effects.As the degree of sophistication in climate change adaptation activities, modelling and cost estimation increases, along with the anticipated growth in interest of both company boards and managers, it is expected that accounting standards, ASX listing rules and disclosures required under the Corporations Act would need to explicitly reflect these corporate actions. The asset allocation of banks, mutual funds, superannuation funds and other investments is also likely to adapt as companies quantify their exposure to climate change. The makeup of assets in investment portfolios may therefore markedly shift, and thus indirectly adjust to the climate change adaptation activities of companies in the broader market

Lessons Learned and Next Steps in Energy Efficiency Measurement and Attribution: Energy Savings, Net to Gross, Non-Energy Benefits, and Persistence of Energy Efficiency Behavior

This white paper examines four topics addressing evaluation, measurement, and attribution of direct and indirect effects to energy efficiency and behavioral programs: Estimates of program savings (gross); Net savings derivation through free ridership / net to gross analyses; Indirect non-energy benefits / impacts (e.g., comfort, convenience, emissions, jobs); and, Persistence of savings

From Structures to Services. The Path toBetter Infrastructure in Latin America and the Caribbean

To close its infrastructure gap, Latin America and the Caribbean needs more than investment in new structures. It needs to become more efficient at investing in infrastructure and regulating a new range of services that have the potential to disrupt the energy, transport, and water sectors. The technological revolution makes a future with quality services possible, but not inevitable. This book offers policy options for countries to improve the access, quality, and affordability of services today, to ensure that they will be sustainable in the future, and to harness emerging technological advances for the benefit of all. This report aims to provoke discussion and further research on those many important issues and mark a path that helps the region move from structures to services and improve infrastructure for all

MITOCHONDRIAL MEMORY AT SKELETAL MUSCLE LEVEL

Mitochondria are key components of skeletal muscles as they provide the energy required for almost all cellular activities. Different forms of exercise training have been associated with mitochondrial adaptations, such as increased mitochondrial content and function, and enhanced mitochondrial biogenesis, as well as improved endurance performance. High-intensity interval training and sprint interval training have been demonstrated to be the most effective training modalities to induce mitochondrial adaptations. However, surprisingly, greater changes in mitochondrial content and biogenesis were also observed after repeated resistance training interventions separated by prolonged detraining. This mechanism, defined muscle memory, has been well established for hypertrophy and skeletal muscle growth in response to resistance training and it has been related to the retention of acquired myonuclei or epigenetic modifications. Thereby, even mitochondrial adaptations might be influenced by muscle memory, but it remains to be explored whether repeated endurance training interventions can rely on the same mechanism. Therefore, the overarching aim of the present thesis was to investigate the potential presence of mitochondrial memory in response to repeated high- intensity endurance training interventions. An experimental design composed of two periods of 8 weeks of interval training interspersed by 3 months of detraining was conducted on murine model and humans. In mice, maximal running velocity (Vmax) by graded exercise test (GXT) on a rodent treadmill. In addition, biomarkers of mitochondrial biogenesis and content, and fusion-fission mitochondrial key factors were analyzed on gastrocnemius muscle by western Blot. Results revealed that endurance performance improved to a greater extent after retraining than training. This functional adaptation was supported by a larger mitochondrial content resulting from a more pronounced mitochondrial biogenesis response after retraining. Mitochondrial dynamics were shifted mainly towards fusion, suggesting larger and more elongated mitochondria and finally, the retraining period elicited increased mitophagic flux, which, associated with a smaller increment in the amount of respiratory chain complexes, suggests an improvement in clearance of damaged mitochondria in order to ensure healthier mitochondria and more efficient respiratory function. In humans, maximal aerobic capacity and peak power output were measured and muscle sample from vastus lateralis was used for mitochondrial respiration and epigenetic analysis. Mitochondrial function resulted in a greater improvement after high intensity aerobic stimulus when previous exposure to an identical stimulus has been occurred separated by long-term period of stimulus cessation. The underlying mechanism could reside in epigenetic modifications induced by interval training which led to DNA hypomethylation. Two memory profiles were highlighted at epigenetic level characterized by retention of hypomethylation even during the prolonged detraining period and involving differentially methylated regions related with genes implicated in skeletal muscle metabolic pathways. Overall, these studies provided evidence for a skeletal muscle memory mechanism, specifically at mitochondrial level, elicited by high-intensity aerobic training that affects muscle aerobic phenotype initiating at the epigenetic level and extends upstream to affect mitochondrial function and endurance performance