Limit Your Consumption! Finding Bounds in Average-energy Games

Energy games are infinite two-player games played in weighted arenas with quantitative objectives that restrict the consumption of a resource modeled by the weights, e.g., a battery that is charged and drained. Typically, upper and/or lower bounds on the battery capacity are part of the problem description. Here, we consider the problem of determining upper bounds on the average accumulated energy or on the capacity while satisfying a given lower bound, i.e., we do not determine whether a given bound is sufficient to meet the specification, but if there exists a sufficient bound to meet it. In the classical setting with positive and negative weights, we show that the problem of determining the existence of a sufficient bound on the long-run average accumulated energy can be solved in doubly-exponential time. Then, we consider recharge games: here, all weights are negative, but there are recharge edges that recharge the energy to some fixed capacity. We show that bounding the long-run average energy in such games is complete for exponential time. Then, we consider the existential version of the problem, which turns out to be solvable in polynomial time: here, we ask whether there is a recharge capacity that allows the system player to win the game. We conclude by studying tradeoffs between the memory needed to implement strategies and the bounds they realize. We give an example showing that memory can be traded for bounds and vice versa. Also, we show that increasing the capacity allows to lower the average accumulated energy.Comment: In Proceedings QAPL'16, arXiv:1610.0769

Information Feedback, Behaviour and ‘Smart Meters’: Using behavioural economics to improve our knowledge about the potential effectiveness of Smart Meters to use electricity efficiently

As part of the development of the European electricity grid, the EU has decided that ‘Smart Meters’ should be installed in 80% of the households of the EU by 2020. It is expected that this will lead to a reduction of energy use in the residential sector in the order of 10%. Driven by the so-called ‘Information-Deficit’ model, a critical assumption in this policy development is that provision of information, via ‘Smart Meters’, enables energy end-users to make more informed, and thus better, decisions in relation to their energy service demands (e.g. lighting). However, even if there is some evidence that feedback to consumers stimulate an efficient use of energy, the magnitude of this reduction is debated. In fact, findings from behavioural economics suggest that behavioural biases (e.g. loss aversion) and cognitive limitations restrict end-users from displaying purely rational behaviour, which in turn limits the effect (and policy expectations) of policies applying the information-deficit model. The thesis at hand addresses these issues explicitly and provides empirical analyses of how behavioural biases affects consumers’ response to energy-related information. To that end, experimental research covering eight field exercises and a Smart Meter experiment was conducted. The thesis aimed to generate knowledge about the applicability and implications of using behavioural economics to deliver feedback to electricity consumers. With due limitations, the experiments illustrate that a knowledge-gap exists, and that information can help correct consumer behaviour, but that the framing and salience of this information can affect the magnitude of the response. The Smart Meter experiment on loss aversion took place in a real-life setting where consumers actually used and paid for the electricity. Results show that the intervention group reduced its electricity use, and that those reductions were larger than those found for the reference group (for both daily and standby consumption). Compared to related research, findings revealed that reductions in electricity use were also larger than the average electricity reduction found in other studies of feedback on electricity use. As a whole, it is concluded that feedback information can contribute to efficient electricity use and thus contribute to meeting EU policy targets. However, the (expected) effects depend on how feedback is designed, framed and presented. The Smart Meter experiment indicates an enhanced effect on electricity use reduction as a result loss aversion, but further research (e.g. large scale trials) is needed for more conclusive and statistically significant results

Average-energy games

Two-player quantitative zero-sum games provide a natural framework to synthesize controllers with performance guarantees for reactive systems within an uncontrollable environment. Classical settings include mean-payoff games, where the objective is to optimize the long-run average gain per action, and energy games, where the system has to avoid running out of energy. We study average-energy games, where the goal is to optimize the long-run average of the accumulated energy. We show that this objective arises naturally in several applications, and that it yields interesting connections with previous concepts in the literature. We prove that deciding the winner in such games is in NP inter coNP and at least as hard as solving mean-payoff games, and we establish that memoryless strategies suffice to win. We also consider the case where the system has to minimize the average-energy while maintaining the accumulated energy within predefined bounds at all times: this corresponds to operating with a finite-capacity storage for energy. We give results for one-player and two-player games, and establish complexity bounds and memory requirements.Comment: In Proceedings GandALF 2015, arXiv:1509.0685

Drivers of natural gas price divergence between NBP and TTF in 2022

The European gas market has undergone substantial transformations and fluctuations in recent years, resulting in a decoupling in natural gas prices between trading hubs in 2022. Specifically, the Title Transfer Facility (TTF) in the Netherlands and the National Balancing Point (NBP) in the United Kingdom experienced large deviations. Utilization of liquefied natural gas (LNG) as a supplement to pipeline imports has increased significantly after discontinuation of gas trade between Europe and Russia. The European gas market experienced constraints in supply and demand due to various factors, leading to elevated prices. The United Kingdom encountered a significant storage capacity crisis, necessitating the export of surplus natural gas to the Netherlands. The study of the natural gas market implemented a combination of qualitative and quantitative methodologies, including the utilization of Vector Auto-Regression (VAR) models, correlation-, cointegration-, and Granger causality analysis. As Europe sought to replace the Russian gas supply with LNG, the Netherlands' relatively low LNG import capacity hindered the country to fully exploit the expanded use of LNG. Furthermore, pipeline maintenance on the Netherlands' connections to Norwegian gas, coupled with the surplus gas in the UK, resulted in capacity constraints on the direct pipeline connection between NBP and TTF. The fundamental economic theory of supply and demand demonstrated how the shortage of supply in the Netherlands generated higher prices for natural gas in the country. The exhaustion of storage facilities in the UK contributed to limits on arbitrage, causing downward price spikes in the NBP compared to TTF, as predicted by storage theory. Data analysis revealed that although the European gas market traditionally functioned as a highly integrated and efficient market, it became disjointed and less efficient in 2022, thereby increasing market predictability. The study's outcome was accordant to economic theories and findings from the conducted analysis. The findings emphasize the necessity for diversified natural gas supply sources, adequate storage capacity, and efficient transportation infrastructure to ensure a reliable and sustainable gas supply in Europe. In practical terms, the analysis results can potentially assist energy traders and analysts in making more informed decisions regarding gas contracts. By monitoring gas flow through connecting pipelines and analysing storage levels, they can make more accurate predictions about future price movements and adjust their trading strategies accordingly

Contrasts in freedom: Comparing the experiences of imprisonment in open and closed prisons in England and Wales and Norway

Open prisons are portrayed as less harmful custodial institutions than closed prisons, and prison systems that rely more heavily on low security imprisonment are typically considered to have a more humane and less punitive approach to punishment. However, few studies have systematically compared the subjective experiences of prisoners held in open and closed prisons, and no study has yet compared the role and function of open prisons across jurisdictions. Drawing on a survey conducted with prisoners (N = 1082) in 13 prisons in England and Wales and Norway, we provide the first comparative analysis of experiences of imprisonment in closed and open prisons, conducted in countries with diverging penal philosophies (‘neoliberal’ vs. ‘social democratic’). The article documents that open prisons play a much more significant role in Norway than in England and Wales; that prisoners in both countries rate their experience significantly more positively in open compared to closed prisons; and that while imprisonment seems to produce similar kinds of pains in both types of prisons, they are perceived as less severe and more manageable in open prisons. These findings suggest important implications for comparative penology, penal policy, and prison reform.publishedVersio

Polynomial Time Decidability of Weighted Synchronization under Partial Observability

We consider weighted automata with both positive and negative integer weights on edges and study the problem of synchronization using adaptive strategies that may only observe whether the current weight-level is negative or nonnegative. We show that the synchronization problem is decidable in polynomial time for deterministic weighted automata