An evaluation framework for input variable selection algorithms for environmental data-driven models

Abstract not availableStefano Galelli, Greer B. Humphrey, Holger R. Maier, Andrea Castelletti, Graeme C. Dandy, Matthew S. Gibb

Improved validation framework and R-package for artificial neural network models

Validation is a critical component of any modelling process. In artificial neural network (ANN) modelling, validation generally consists of the assessment of model predictive performance on an independent validation set (predictive validity). However, this ignores other aspects of model validation considered to be good practice in other areas of environmental modelling, such as residual analysis (replicative validity) and checking the plausibility of the model in relation to a priori system understanding (structural validity). In order to address this shortcoming, a validation framework for ANNs is introduced in this paper that covers all of the above aspects of validation. In addition, the validann R-package is introduced that enables these validation methods to be implemented in a user-friendly and consistent fashion. The benefits of the framework and R-package are demonstrated for two environmental modelling case studies, highlighting the importance of considering replicative and structural validity in addition to predictive validity

Developing scholarship through collaboration in an online roleplay-simulation: Mekong eSim, a case study

Mekong e-Sim was designed to create an authentic learning environment in which students from different disciplines work together to learn about the complexities of environmental decision-making. The version of Mekong e-Sim that is reported here involved students of the subjects Asia-Pacific Development (geography), Technology Assessment (technological developments and impacts in engineering) and Environmental Engineering. During the Mekong e-Sim, students collaborated to adopt different stakeholder roles and initiate and respond to major events relating to economic and environmental development in the Mekong region. Key tasks included responding to topical news events, making submissions to public planning inquiries, writing reports and debating development issues in the Mekong region. Through their participation in Mekong e-Sim, students developed understanding of the complexities of decision-making, appreciation of the range of perspectives associated with environmental management and developed subject specific skills and understandings. A description of the design and evaluation of the Mekong e-Sim is provided in McLaughlan et al. (2001). The development of the teaching project was a collaborative, cross-institutional teaching development that brought together staff with a range of skills and expertise. Despite the fact that there has been increasing attention to scholarly values in universities in recent years there has been little consideration of what this might look like. This paper uses the case of the development and teaching of Mekong e-Sim to investigate scholarly teaching, particularly the process and practice of scholarship and teaching in a team situation

Using Online Roleplay/Simulations for Creating Learning Experiences

Over 140 geography and engineering students from across Australia and overseas spent 4 weeks participating in an online roleplay-simulation set in the Mekong region of South East Asia. The online environment provides a setting for the construction of alternative points of view and a lively debate and creates an authentic context for student collaboration. The roleplay-simulation involves decision-making and conflict resolution regarding natural resource development. The Mekong e-Sim (electronic simulation) has been designed to support the learning of students studying subjects in the subjects Technology Assessment, Environmental Engineering or Asia Pacific Development Studies at different universities. The students share the online roleplay simulation experience, which is then utilised differently within each of the geography or engineering subjects at the institution where the students are enrolled. Student and staff response has been very positive. Students report that the e-Sim provides a realistic experience, is engaging, develops their information technology and communication skills and increases their awareness of multiple perspectives on the issues involved

Multiobjective optimization of water distribution systems accounting for economic cost, hydraulic reliability, and greenhouse gas emissions

In this paper, three objectives are considered for the optimization of water distribution systems (WDSs): the traditional objectives of minimizing economic cost and maximizing hydraulic reliability and the recently proposed objective of minimizing greenhouse gas (GHG) emissions. It is particularly important to include the GHG minimization objective for WDSs involving pumping into storages or water transmission systems (WTSs), as these systems are the main contributors of GHG emissions in the water industry. In order to better understand the nature of tradeoffs among these three objectives, the shape of the solution space and the location of the Pareto-optimal front in the solution space are investigated for WTSs and WDSs that include pumping into storages, and the implications of the interaction between the three objectives are explored from a practical design perspective. Through three case studies, it is found that the solution space is a U-shaped curve rather than a surface, as the tradeoffs among the three objectives are dominated by the hydraulic reliability objective. The Pareto-optimal front of real-world systems is often located at the "elbow" section and lower "arm" of the solution space (i.e., the U-shaped curve), indicating that it is more economic to increase the hydraulic reliability of these systems by increasing pipe capacity (i.e., pipe diameter) compared to increasing pumping power. Solutions having the same GHG emission level but different cost-reliability tradeoffs often exist. Therefore, the final decision needs to be made in conjunction with expert knowledge and the specific budget and reliability requirements of the system. © 2013. American Geophysical Union. All Rights Reserved.Wenyan Wu, Holger R. Maier, and Angus R. Simpso

Ant colony optimization for design of water distribution systems

During the last decade, evolutionary methods such as genetic algorithms have been used extensively for the optimal design and operation of water distribution systems. More recently, ant colony optimization algorithms ~ACOAs!, which are evolutionary methods based on the foraging behavior of ants, have been successfully applied to a number of benchmark combinatorial optimization problems. In this paper, a formulation is developed which enables ACOAs to be used for the optimal design of water distribution systems. This formulation is applied to two benchmark water distribution system optimization problems and the results are compared with those obtained using genetic algorithms ~GAs!. The findings of this study indicate that ACOAs are an attractive alternative to GAs for the optimal design of water distribution systems, as they outperformed GAs for the two case studies considered both in terms of computational efficiency and their ability to find near global optimal solutions.Holger R. Maier, Angus R. Simpson, Aaron C. Zecchin, Wai Kuan Foong, Kuang Yeow Phang, Hsin Yeow Seah and Chan Lim Ta

Exploding the myths: An introduction to artificial neural networks for prediction and forecasting

Artificial Neural Networks (ANNs), sometimes also called models for deep learning, are used extensively for the prediction of a range of environmental variables. While the potential of ANNs is unquestioned, they are surrounded by an air of mystery and intrigue, leading to a lack of understanding of their inner workings. This has led to the perpetuation of a number of myths, resulting in the misconception that applying ANNs primarily involves "throwing" a large amount of data at "black-box" software packages. While this is a convenient way to side-step the principles applied to the development of other types of models, this comes at significant cost in terms of the usefulness of the resulting models. To address these issues, this inroductory overview paper explodes a number of the common myths surrounding the use of ANNs and outlines state-of-the-art approaches to developing ANNs that enable them to be applied with confidence in practice

Integrating modelling and smart sensors for environmental and human health.

Sensors are becoming ubiquitous in everyday life, generating data at an unprecedented rate and scale. However, models that assess impacts of human activities on environmental and human health, have typically been developed in contexts where data scarcity is the norm. Models are essential tools to understand processes, identify relationships, associations and causality, formalize stakeholder mental models, and to quantify the effects of prevention and interventions. They can help to explain data, as well as inform the deployment and location of sensors by identifying hotspots and areas of interest where data collection may achieve the best results. We identify a paradigm shift in how the integration of models and sensors can contribute to harnessing 'Big Data' and, more importantly, make the vital step from 'Big Data' to 'Big Information'. In this paper, we illustrate current developments and identify key research needs using human and environmental health challenges as an example.E.S. is funded by NIH R21ES024715. M.C. gratefully acknowledges the Minnesota Discovery, Research and InnoVation Economy (MnDRIVE) “Global Food Venture” funding and the Institute on the Environment “Discovery Grant” funding at the University of Minnesota Twin-Cities. S.R. and S.S. acknowledge the support for the conceptual development and testing of personal exposure monitoring methods by the UK Natural Environment Research Council through National Capability funding.This is the final version of the article. It was first available from Elsevier via http://dx.doi.org/10.1016/j.envsoft.2015.06.00