On the use of surrogate-based modeling for the numerical analysis of Low Impact Development techniques

Mechanistic models have proven to be accurate tools for the numerical analysis of the hydraulic behavior of Low Impact Development (LIDs) techniques. However, their widespread adoption has been limited by their computational cost. In this view, surrogate modeling is focused on developing and using a computationally inexpensive surrogate of the original model. While having been previously applied to various water-related and environmental modeling problems, no studies have used surrogate models for the analysis of LIDs. The aim of this research thus was to investigate the benefit of surrogate-based modeling in the numerical analysis of LIDs. The kriging technique was used to approximate the deterministic response of the widely used mechanistic model HYDRUS-2D, which was employed to simulate the variably-saturated hydraulic behavior of a contained stormwater filter. The Nash-Sutcliffe efficiency (NSE) index was used to compare the simulated and measured outflows and as the variable of interest for the construction of the response surface. The validated kriging model was first used to carry out a Global Sensitivity Analysis of the unknown soil hydraulic parameters of the filter layer, revealing that only the shape parameter α and the saturated hydraulic conductivity Ks significantly affected the model response. Next, the Particle Swarm Optimization algorithm was used to estimate their values. The NSE value of 0.85 indicated a good accuracy of estimated parameters. Finally, the calibrated model was validated against an independent set of measured outflows with a NSE value of 0.8, which again corroborated the reliability of the surrogate-based optimized parameters

Promoting reuse behaviour: Challenges and strategies for repeat purchase, low-involvement products

Reusable products offer reduced environmental impact compared to recycling, but producers mostly focus on strategies such as light-weighting, recyclability and eco-labelling. A reasonable number of innovative reusable products and business models exist for repeat purchase, low-involvement products, but they are largely restricted to niche health-food stores. Therefore, this research primarily attempts to understand consumer attitudes and behaviour towards reuse of household care products (e.g. air fresheners, domestic cleaning products). Focus groups with UK consumers are utilised to examine reusable/refillable spray products and the data are triangulated with global archival data on various refill business models, reusable products and recycling initiatives. The study offers useful guidelines for both producers and policy makers to encourage reusable products. First, we recommend that eco-innovations have a familiar design congruent with well-known brands, to reduce uncertainties for consumers. Second, if the innovation has an unfamiliar design, to mitigate, producers should offer new functional benefits. Third, and most important, producers must place greater emphasis on aesthetic aspects that could evoke product attachment, thus encouraging reuse. Fourth, if reusable products are to become mainstream, ‘well-known brands’ have to promote the transition from one-off sales to a service model built on durable products. Finally, a successful outcome is dependent on government interventions in designing new life cycle policy instruments, in particular de-marketing the current recycling norm and emphasising reusing over recycling

Wearables in medicine

Wearables as medical technologies are becoming an integral part of personal analytics, measuring physical status, recording physiological parameters, or informing schedule for medication. These continuously evolving technology platforms do not only promise to help people pursue a healthier life style, but also provide continuous medical data for actively tracking metabolic status, diagnosis, and treatment. Advances in the miniaturization of flexible electronics, electrochemical biosensors, microfluidics, and artificial intelligence algorithms have led to wearable devices that can generate real-time medical data within the Internet of things. These flexible devices can be configured to make conformal contact with epidermal, ocular, intracochlear, and dental interfaces to collect biochemical or electrophysiological signals. This article discusses consumer trends in wearable electronics, commercial and emerging devices, and fabrication methods. It also reviews real-time monitoring of vital signs using biosensors, stimuli-responsive materials for drug delivery, and closed-loop theranostic systems. It covers future challenges in augmented, virtual, and mixed reality, communication modes, energy management, displays, conformity, and data safety. The development of patient-oriented wearable technologies and their incorporation in randomized clinical trials will facilitate the design of safe and effective approaches

Instances of Instantiation: Distinguishing between Subjective and Objective Properties

This thesis explores the prospects of a distinction between subjective and objective properties in terms of how they are instantiated. While there are many ways in which the subjective can be separated from the objective, the one that interests me here is the difference between properties instantiated subjectively and properties instantiated objectively. The idea is that in some cases what makes it so that object o has the property p is what a thinking subject thinks of it or how she reacts to it, while in other cases what makes it so that o has p has nothing to do with what the subject thinks or does. In the first kind of case, the instantiation of the property is mind-dependent, or subjective, and in the second kind of case the instantiation is mind-independent, or objective. I examine ways to draw a distinction between subjective and objective properties in this sense and defend the possibility of such a distinction against conceivable threats. I then go on to arguing that instead of sorting properties into two groups, subjective and objective, it is more fruitful to think of them as on a continuum ranging from entirely subjective to entirely objective. While there may be cases of properties that are entirely objective, i.e. instantiated only objectively, finding entirely subjective properties if more difficult. Candidates for subjective properties do not seem to be exclusively subjective; i.e. they are instantiated objectively to some extent. I use color as a paradigm case to argue for my account of properties whose instantiation is partly objective and partly subjective. I then go on to arguing that all sensory properties should be treated as color in this respect

The Cornell Digital Reading Room Ergonomics Checklist: Development and Evaluation

Currently there exists no strategy for evaluating digital radiology reading rooms. This is of concern since the number of symptomatic radiologists suffering from work related musculoskeletal problems seems to be on the rise. Work related musculoskeletal complaints have been shown to be related to workstation set up, chair settings, monitor placement and other issues related to the computer workstation. Due to the visually intensive nature of the work of radiologists working with digital medical images, it is also important to look at factors in the ambient environment, such as lighting. A checklist was developed to evaluate environmental factors in the work environment of radiologists. The checklist contained 39 questions divided into sections on display screens, input devices, workstation and workstation accessories, chair and ambient conditions. The items in the checklist were taken from checklists and educational material published for example by independent researchers, the Occupational Health and Safety Administration (OSHA) and the Canadian Standards Association. Answer options for each item consisted of factual statements, measurements, rating or a simple description. Some answer options included images for postural comparison. The checklist was not accompanied by a scoring sheet, but items that, if answered in a particular way, could be classified as ?Ergonomic Issues? were identified in the checklist instructions and layout. To evaluate the checklist, a mailing survey was sent to practicing radiologists, hospital administrators, ergonomists and other health and safety professionals. In the survey, respondents were asked four questions, both open ended and closed-ended, relating to the usability, layout and overall comprehensiveness of the checklist. The experts were also encouraged to provide general comments on the checklist. Twelve non-factual items or items that required rating or subjective scoring were tested with multiple rater agreement (interrater reliability) and by percent agreement between participants and between participants and an ergonomist. The individual items were tested by asking participants to base their answers based on a series of standardized images depicting a model radiologist performing various tasks, such as reading an image from a computer monitor, use a computer mouse and telephone. Twenty one participants, aged 18-58 years old completed the Interrater reliability - Individual Item Test. Six were male and 15 female. Eight participants were experts, or had background in ergonomics, facility planning and management or similar human-environment relations fields. The Interrater reliability of the items tested was .50 (p< 0.05) for the experts, and 0.10 for the novices (p<0.05). When the results of participant agreement for individual items were analyzed, four items had consistently lower agreement. Three of these items were modified in accordance with expert feedback and one was excluded from the final version of the checklist. The final version of the checklist contained 43 items. Limitations to this study include the design of the individual item test, not utilizing realistic situation with participants actually observing a radiologist at work, but basing their ratings off images that were not consistent in terms of posture and content. Further limitations also include the limited number of expert feedback received. In spite of the idea that invested experts would provide good feedback, it would prove beneficial to know why some experts chose not to participate. Future research directions include a more comprehensive test of the checklist, both including the entire checklist as well as testing the checklist in actual digital reading rooms. An interesting application of this type of environmental checklist is to adapt it for computer based use, utilizing either portable hospital computer workstations or palm pilots would enable synchronization of information in a centralized facility database as well as instant access to results and possibly feedback. It would be very interesting to see an interactive version of this checklist developed and tested in the future. This is particularly relevant with hospital environments becoming increasingly a digital workplace

Data-Driven I–V Feature Extraction for Photovoltaic Modules

In research on photovoltaic (PV) device degradation, current-voltage (I-V ) datasets carry a large amount of information in addition to the maximum power point. Performance parameters such as short-circuit current, open-circuit voltage, shunt resistance, series resistance, and fill factor are essential for diagnosing the performance and degradation of solar cells and modules. To enable the scaling of I-V studies to millions of I-V curves, we have developed a data-driven method to extract I-V curve parameters and distributed this method as an open-source package in R. In contrast with the traditional practice of fitting the diode equation to I-V curves individually, which requires solving a transcendental equation, this data-driven method can be applied to large volumes of I-V data in a short time. Our data-driven feature extraction technique is tested on I-V curves generated with the single-diode model and applied to I-V curves with different data point densities collected from three different sources. This method has a high repeatability for extracting I-V features, without requiring knowledge of the device or expected parameters to be input by the researcher. We also demonstrate how this method can be applied to large datasets and accommodates nonstandard I-V curves including those showing artifacts of connection problems or shading where bypass diode activation produces multiple “steps.” These features together make the data-driven I-V feature extraction method ideal for evaluating time-series I-V data and analyzing power degradation mechanisms in PV modules through cross comparisons of the extracted parameters