arXiv subjects

Edward Wheatcroft

Publications and source records attributed to Edward Wheatcroft.

8 recordsLinked to original sources

arXiv2021

Comparing district heating options under uncertainty using stochastic ordering

District heating is a network of pipes through which heat is delivered from a centralised source. It is expected to play an important role in the decarbonisation of the energy sector in the coming years. In district heating, heat is traditionally generated through fossil fuels, often with combined heat and power (CHP) units. However, increasingly, waste heat is being used as a low carbon alternative, either directly or, for low temperature sources, via a heat pump. The design of district heating often has competing objectives: the need for inexpensive energy and meeting low carbon targets. In addition, the planning of district heating schemes is subject to multiple sources of uncertainty such as variability in heat demand and energy prices. This paper proposes a decision support tool to analyse and compare system designs for district heating under uncertainty using stochastic ordering (dominance). Contrary to traditional uncertainty metrics that provide statistical summaries and impose total ordering, stochastic ordering is a partial ordering and operates with full probability distributions. In our analysis, we apply the orderings in the mean and dispersion to the waste heat recovery problem in Brunswick, Germany.

stat.AP↗

arXiv2021

Majorisation as a theory for uncertainty

Majorisation, also called rearrangement inequalities, yields a type of stochastic ordering in which two or more distributions can be compared. In this paper we argue that majorisation is a good candidate as a theory for uncertainty. We present operations that can be applied to study uncertainty in a range of settings and demonstrate our approach to assessing uncertainty with examples from well known distributions and from applications of climate projections and energy systems.

math.ST↗

arXiv2021

A Probabilistic Model for Predicting Shot Success in Football

Football forecasting models traditionally rate teams on past match results, that is based on the number of goals scored. Goals, however, involve a high element of chance and thus past results often do not reflect the performances of the teams. In recent years, it has become increasingly clear that accounting for other match events such as shots at goal can provide a better indication of the relative strengths of two teams than the number of goals scored. Forecast models based on this information have been shown to be successful in outperforming those based purely on match results. A notable weakness, however, is that this approach does not take into account differences in the probability of shot success among teams. A team that is more likely to score from a shot will need fewer shots to win a match, on average. In this paper, we propose a simple parametric model to predict the probability of a team scoring, given it has taken a shot at goal. We show that the resulting forecasts are able to outperform a model assuming an equal probability of shot success among all teams. We then show that the model can be combined with predictions of the number of shots achieved by each team, and can increase the skill of forecasts of both the match outcome and of whether the total number of goals in a match will exceed 2.5. We assess the performance of the forecasts alongside two betting strategies and find mixed evidence for improved performance.

stat.AP↗

arXiv2020

Assessing the Significance of Model Selection in Ecology

Model Selection is a key part of many ecological studies, with Akaike's Information Criterion the most commonly used technique. Typically, a number of candidate models are defined a priori and ranked according to their expected out-of-sample performance. Model selection, however, only assesses the relative performance of the models and, as pointed out in a recent paper, a large proportion of ecology papers that use model selection do not assess the absolute fit of the `best' model. In this paper, it is argued that assessing the absolute fit of the `best' model alone does not go far enough. This is because a model that appears to perform well under model selection is also likely to appear to perform well under measures of absolute fit, even when there is no predictive value. A model selection permutation test is proposed that assesses the probability that the model selection statistic of the `best' model could have occurred by chance alone, whilst taking account of dependencies between the models. It is argued that this test should always be performed before formal model selection takes place. The test is demonstrated on two real population modelling examples of ibex in northern Italy and wild reindeer in Norway.

stat.AP↗

arXiv2020

Forecasting football matches by predicting match statistics

This paper considers the use of observed and predicted match statistics as inputs to forecasts of the outcomes of football matches. It is shown that, were it possible to know the match statistics in advance, highly informative forecasts of the match outcome could be made. Whilst, in practice, match statistics are never available prior to the match, this leads to a simple philosophy. If match statistics can be predicted pre-match, and if those predictions are accurate enough, it follows that informative match forecasts can be made. It is shown that Generalised Attacking Performance (GAP) ratings, introduced in a recent paper, provide a suitable methodology for predicting match statistics in advance and that they are informative enough to provide information beyond that reflected in the odds. A long term and robust gambling profit is demonstrated when the forecasts are combined with two betting strategies.

stat.AP↗

arXiv2019

The role of low temperature waste heat recovery in achieving 2050 goals: a policy positioning paper

Urban waste heat recovery, in which low temperature heat from urban sources is recovered for use in a district heat network, has a great deal of potential in helping to achieve 2050 climate goals. For example, heat from data centres, metro systems, public sector buildings and waste water treatment plants could be used to supply ten percent of Europe's heat demand. Despite this, at present, urban waste heat recovery is not widespread and is an immature technology. To help achieve greater uptake, three policy recommendations are made. First, policy raising awareness of waste heat recovery and creating a legal framework is suggested. Second, it is recommended that pilot projects are promoted to help demonstrate technical and economic feasibility. Finally, a pilot credit facility is proposed aimed at bridging the gap between potential investors and heat recovery projects.

econ.GN↗

arXiv2019

The Scenario Culture

Scenario Analysis is a risk assessment tool that aims to evaluate the impact of a small number of distinct plausible future scenarios. In this paper, we provide an overview of important aspects of Scenario Analysis including when it is appropriate, the design of scenarios, uncertainty and encouraging creativity. Each of these issues is discussed in the context of climate, energy and legal scenarios.

stat.OT↗

arXiv2019

Evaluating probabilistic forecasts of football matches: The case against the Ranked Probability Score

A scoring rule is a function of a probabilistic forecast and a corresponding outcome that is used to evaluate forecast performance. A wide range of scoring rules have been defined over time and there is some debate as to which are the most appropriate for evaluating the performance of forecasts of sporting events. This paper focuses on forecasts of the outcomes of football matches. The ranked probability score (RPS) is often recommended since it is `sensitive to distance', that is it takes into account the ordering in the outcomes (a home win is `closer' to a draw than it is to an away win, for example). In this paper, this reasoning is disputed on the basis that it adds nothing in terms of the actual aims of using scoring rules. A related property of scoring rules is locality. A scoring rule is local if it only takes the probability placed on the outcome into consideration. Two simulation experiments are carried out in the context of football matches to compare the performance of the RPS, which is non-local and sensitive to distance, the Brier score, which is non-local and insensitive to distance, and the ignorance score, which is local and insensitive to distance. The ignorance score is found to outperform both the RPS and the Brier score, casting doubt on the value of non-locality and sensitivity to distance as properties of scoring rules in this context.

stat.AP↗