Mobile application testing is a specialised and complex field. Due to mobile applications' event driven design and mobile runtime environment, there currently exist only a small number of tools to verify these applications. This paper describes the development of JPF-ANDROID, an Android application verification tool. JPF-ANDROID is built on Java Pathfinder, a Java model checking engine. JPF-ANDROID provides a simplified model of the Android framework on which an Android application can run. It then allows the user to script input events to drive the application flow. JPF-ANDROID provides a way to detect common property violations such as deadlocks and runtime exceptions in Android applications.

Electric water heaters (EWHs) remain one of the main contributors to energy consumption in countries where they are used. EWH models serve as a step towards achieving optimised control, and can also be used to inform users of expected savings due to changes, if the model is energy-based. Various models have been proposed, but none of them include more than half of the six key features that the model presented in this paper supports: horizontal orientation; schedule control; low computational complexity; validation of the model; multinodal stratification; and multinodal standing losses. The presented model is validated against six datasets: four comprising 900 hours with multiple water usage events; and two with only standing losses. The results show that the model estimates energy consumption over ten days including usage with an error of less than 2% and 5% for schedule control and thermostat control respectively. The simulation model is simple enough to execute ten days of simulation in less than 100 milliseconds on a standard desktop machine, 150 times faster than a prominent model from literature, making it also suitable for large scale simulations or for use on mobile devices.

Given the pressures on the world's freshwater resources, recycled water is a valuable resource. Recycled water can increase the reliability of water supply because it is an independent source of water. Water recycling requires effective measures to protect public health and the environment. In the absence of comprehensive international guidelines, different countries have developed different approaches to managing water recycling depending on the understanding of the health risks, their individual economic circumstances, and affordability. Approaches vary between high technology/high cost/low risk and low technology/low cost/controlled risk. Furthermore, differences occur between countries and within individual countries. Inconsistencies can often be traced to lack of a unified scientific position on health effects. These inconsistencies increase public concerns about health risks and may give rise to conservative controls on responses to water recycling projects that some countries may be unable to afford. In this paper, an international panel of authors discusses how the different water recycling approaches might be linked together into international water recycling guidelines. These guidelines would incorporate a uniform approach to assessing hazards and risks while providing flexibility for individual countries to vary requirements to suit local circumstances of affordability and risk. The authors propose a framework of guidelines in which individual countries can progressively improve recycled water quality as lower risk levels become more affordable. The authors argue that a uniform international approach will result in a number of benefits including a better focus on risk management, better targeted research and development efforts and greater public confidence in water recycling. The authors invite discussion on the concepts put forward in the paper.

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Electric water heaters (EWHs) remain one of the main contributors to energy consumption in countries where they are used. EWH models serve as a step towards achieving optimised control, and can also be used to inform users of expected savings due to changes, if the model is energy-based. Various models have been proposed, but none of them include more than half of the six key features that the model presented in this paper supports: horizontal orientation; schedule control; low computational complexity; validation of the model; multinodal stratification; and multinodal standing losses. The presented model is validated against six datasets: four comprising 900 hours with multiple water usage events; and two with only standing losses. The results show that the model estimates energy consumption over ten days including usage with an error of less than 2% and 5% for schedule control and thermostat control respectively. The simulation model is simple enough to execute ten days of simulation in less than 100 milliseconds on a standard desktop machine, 150 times faster than a prominent model from literature, making it also suitable for large scale simulations or for use on mobile devices.

Abstract-Electric heating of water for domestic use is a substantial component of total household energy costs. Thermal energy in a water heater is either used (as warm water) or lost to the environment. Various approaches to reduce the losses and improve the efficiency of these notoriously inefficient and costly water heaters have been proposed and are employed. However, given the complex factors at play, making sense of the savings approaches and choosing the right one for the right use case is not a simple task and often misunderstood. This paper addresses this problem by comparing some of the commonly employed approaches, including schedule control, change in set temperature, use of thermal insulation, and reduction in consumed volume. We also compare the impact of environmental factors, such as changing the ambient temperature around the water heater and the cold inlet temperature. The results show that for the consumption profiles and use cases evaluated, schedule control is the most effective, followed by insulation of the tank and piping. Combined, these two interventions save up to 25%. We also find that the effect of the temperature of the cold inlet water dwarfs that of the ambient temperature, is in line with other approaches, and means the installation status quo needs to be reconsidered.

Android applications are difficult to verify and test since they have many external dependencies. To overcome this problem, environment generation can be used to create a model of the environment to simulate the behavior of these external dependencies. Creating this environment model manually is a tedious process and although there are many techniques available to generate models, the key lies in identifying how these techniques can be applied to a specific domain. In this paper we discuss two static analysis tools OCSEGen [3] and Modgen [1] and how they can be applied to the Android domain to generate models for specific parts of the environment.

Using data from an online national survey conducted in South Africa, this paper aims to investigate: the awareness of energy savings measures for electric water heaters (EWHs); whether or not consumers are implementing suggested measures; and if consumers understand and effectively control their EWHs' energy usage. Additionally, the data is used to determine the success of educational and rebate programmes aimed at reducing residential energy usage and to determine possible motivations for encouraging users to reduce or alter their EWH energy and warm water consumption. The results of this questionnaire indicate that: convenience is a key factor in consumers' willingness to implement curtailment actions; users don't understand the energy consumption of their EWHs; and they don't know how to control their EWHs efficiently.