Micro-economic Analysis of the Physical Constrained Markets: Game Theory Application to Competitive Electricity Markets

Competition has been introduced in the electricity markets with the goal of reducing prices and improving efficiency. The basic idea which stays behind this choice is that, in competitive markets, a greater quantity of the good is exchanged at a lower and a lower price, leading to higher market efficiency. Electricity markets are pretty different from other commodities mainly due to the physical constraints related to the network structure that may impact the market performance. The network structure of the system on which the economic transactions need to be undertaken poses strict physical and operational constraints. Strategic interactions among producers that game the market with the objective of maximizing their producer surplus must be taken into account when modeling competitive electricity markets. The physical constraints, specific of the electricity markets, provide additional opportunity of gaming to the market players. Game theory provides a tool to model such a context. This paper discussed the application of game theory to physical constrained electricity markets with the goal of providing tools for assessing the market performance and pinpointing the critical network constraints that may impact the market efficiency. The basic models of game theory specifically designed to represent the electricity markets will be presented. IEEE30 bus test system of the constrained electricity market will be discussed to show the network impacts on the market performances in presence of strategic bidding behavior of the producers.Comment: Accepted for publication in the European Journal of Physics B. Presented at the Int. Conf. NEXT-SigmaPhi, 13-18 August 2005, Cret

Techno-economic Impacts of COVID-19 Pandemic on the Italian Electricity System

Since the end of 2019, the sadly known Sars-CoV-2 has firstly spread to China and then to the rest of the world, giving rise to the pandemic known as COVID-19. The high number of deaths and the stressful conditions of public health systems suggested governments to impose social restrictions to contain the virus diffusion. The adopted measures differed from country to country, but they often resulted in the closure of schools, workplaces and meeting places. In Italy, in addition to local restrictions adopted in the areas where the health situation was particularly severe, the decree law of March 4, 2020 imposed social restrictions for the entire country (e.g. closure of schools and ban on gatherings). Subsequently, with a series of decree laws, the measures became more severe and on March 22, 2020 the government imposed the lockdown of all face-toface activities related to production chains concerning nonessential goods. These decrees implicated a considerable reduction in the electrical demand with consequent impacts on both electrical markets and operation strategies of the Transmission System Operator (TSO). Due to the low demand, compared to usual load conditions, fewer conventional power plants were dispatched in the Day Ahead Market; therefore, a decrease in the price of energy occurred, as well as an increment of the renewable penetration. At the same time, conventional power plants played a key role in the Ancillary Services Market to ensure the safe operation of the transmission system. In this work, the reduction of the electrical demand and its impacts on both electrical markets and network operation strategies are analysed and discussed for the Italian power system

Enamel matrix derivative in the treatment of peri-implant diseases - a systematic review

Objective: To evaluate the benefit in terms of clinical, histological and radiographic outcomes of the adjunctive use of enamel matrix derivative (Emdogain® ; Straumann, Basel, Switzerland) on the non-surgical and surgical treatment of peri-implant diseases. Methods: A systematic literature search comprised three databases: PubMed, Scopus and Cochrane. Eligible studies were selected based on the inclusion criteria. Results: Seven studies were selected for data extraction. Two randomized clinical trials using Emdogain® as an adjuvant for non-surgical treatment of peri-implant mucositis; tree cohort studies and and two randomized clinical trials using Emdogain® as an adjuvant for surgical treatment of peri-implantitis. A reduction of the mean bleeding on probing (76.6%), probing depth (3.5mm), P. gingivalis counts and mean marginal bone level gain of 2,38±0.92mm was observed. Conclusions: Emdogain® has a positive effect on clinical and microbiological outcome of non-surgical treatment of peri-implant mucositis. Combined with grafting materials, it seems to improve bone fill after surgical treatment of peri-implantitis. More studies are necessary to determine the effects of Emdogain® alone in the clinical outcome of peri-implantitis treatment

Periodontal impact of orthodontic treatment with clear aligners

Objective: To compare the periodontal health of patients treated with conventional fixed appliance and patients treated with clear aligner systems, in various malocclusions. Methods: A systematic literature search comprised three databases: PubMed, B-on and Cochrane. Eligible studies were selected based on the inclusion and exclusion criteria. Results: Seven studies were selected for data extraction, three randomized controlled trials and four cohort studies. The total number of participants making up this systematic review was 390. The plaque index showed a statistically significant differences between patients with fixed orthodontic appliances and clear aligners while the others indices showed no statistically significant differences. Conclusion: This review didn’t found data that support the existence of significant statistic differences between clear aligners and fixed orthodontic appliances regarding periodontal health impact. More studies are needed to clarify this aspect related with the orthodontic treatment.Objetivo: Comparar o status periodontal dos pacientes tratados com aparelhos ortodônticos fixos convencionais e o status periodontal dos pacientes tratados com aparelhos removíveis comummente designados alinhadores, em diferentes más oclusões. Metodologia: Foi realizada uma revisão sistemática da literatura, nas fontes electrónicas de informação seguintes: PubMed, B-on e Cochrane. Foram definidos critérios de inclusão e de exclusão que permitiram a seleção dos artigos analisados no trabalho. Resultados: Foram selecionados sete artigos para revisão, dos quais três respeitavam a ensaios clínicos randomizados controlados e quatro a estudos de coorte. O número total de participantes incluídos nesta revisão foi de 390 indivíduos. A análise dos dados relativos aos índices de placa bacteriana dos pacientes revelam diferenças estatisticamente significativas entre os dois grupos estudados, enquanto na análise dos restantes índices periodontais não se detectam diferenças estatisticamente significativas. Conclusão: Este trabalho não encontrou evidência científica que permita concluir que existem diferenças estatisticamente significativas relativas ao estado de saúde dos tecidos periodontais dos pacientes tratados ortodonticamente, em função do tipo de aparelhos analisados neste estudo. Sugere-se a realização de novas investigações para melhor clarificação deste assunto

RISK ASSESSMENT OF MALICIOUS ATTACKS AGAINST POWER SYSTEMS

The new scenarios of malicious attack prompt for their deeper consideration and mainly when critical systems are at stake. In this framework, infrastructural systems, including power systems, represent a possible target due to the huge impact they can have on society. Malicious attacks are different in their nature from other more traditional cause of threats to power system, since they embed a strategic interaction between the attacker and the defender (characteristics that cannot be found in natural events or systemic failures). This difference has not been systematically analyzed by the existent literature. In this respect, new approaches and tools are needed. This paper presents a mixed-strategy game-theory model able to capture the strategic interactions between malicious agents that may be willing to attack power systems and the system operators, with its related bodies, that are in charge of defending them. At the game equilibrium, the different strategies of the two players, in terms of attacking/protecting the critical elements of the systems, can be obtained. The information about the attack probability to various elements can be used to assess the risk associated with each of them, and the efficiency of defense resource allocation is evidenced in terms of the corresponding risk. Reference defense plans related to the online defense action and the defense action with a time delay can be obtained according to their respective various time constraints. Moreover, risk sensitivity to the defense/attack-resource variation is also analyzed. The model is applied to a standard IEEE RTS-96 test system for illustrative purpose and, on the basis of that system, some peculiar aspects of the malicious attacks are pointed ou

Optimal battery charge/discharge strategies for prosumers and suppliers

We discuss the application of classical variational methods to optimal charging/discharging strategies for a prosumer or storage supplier, where the price of electrical power is known in advance. We outline how a classical calculus of variations approach can be applied to two related problems: (i) how can a prosumer minimise the cost of charging/discharging a battery, when the price of electrical power is known throughout the charging/discharging period? and (ii) how can an electricity supplier incentivise desired prosumer/storage supplier behaviour by adjusting the price

Power grids vulnerability: a complex network approach

Power grids exhibit patterns of reaction to outages similar to complex networks. Blackout sequences follow power laws, as complex systems operating near a critical point. Here, the tolerance of electric power grids to both accidental and malicious outages is analyzed in the framework of complex network theory. In particular, the quantity known as efficiency is modified by introducing a new concept of distance between nodes. As a result, a new parameter called net-ability is proposed to evaluate the performance of power grids. A comparison between efficiency and net-ability is provided by estimating the vulnerability of sample networks, in terms of both the metrics.Comment: 16 pages, 3 figures. Figure 2 and table II modified. Typos corrected. Version accepted for publication in Chao

Thermo-mechanical FE model with memory effect for 304L austenitic stainless steel presenting microstructure gradient

The main purpose of this study is to determine, via a three dimensions Finite Element analysis (FE), the stress and strain fields at the inner surface of a tubular specimen submitted to thermo-mechanical fatigue. To investigate the surface finish effect on fatigue behaviour at this inner surface, mechanical tests were carried out on real size tubular specimens under various thermal loadings. X ray measurements, Transmission Electron Microscopy observations and micro-hardness tests performed at and under the inner surface of the specimen before testing, revealed residual internal stresses and a large dislocation microstructure gradient in correlation with hardening gradients due to machining. A memory effect, bound to the pre-hardening gradient, was introduced into an elasto-visco-plastic model in order to determine the stress and strain fields at the inner surface. The temperature evolution on the inner surface of the tubular specimen was first computed via a thermo-elastic model and then used for our thermo-mechanical simulations. Identification of the thermo-mechanical model parameters was based on the experimental stabilized cyclic tension-compression tests performed at 20^{\circ}C and 300^{\circ}C. A good agreement was obtained between numerical stabilized traction-compression cycle curves (with and without pre-straining) and experimental ones. This 3 dimensional simulation gave access to the evolution of the axial and tangential internal stresses and local strains during the tests. Numerical results showed: a decreasing of the tangential stress and stabilization after 40 cycles, whereas the axial stress showed weaker decreasing with the number of cycles. The results also pointed out a ratcheting and a slightly non proportional loading at the inner surface. The computed mean stress and strain values of the stabilized cycle being far from the initial ones, they could be used to get the safety margins of standard design related to fatigue, as well as to get accurate loading conditions needed for the use of more advanced fatigue analysis and criteria