Artificial Intelligence Search Strategies for Autonomous Underwater Vehicles Applied for Submarine Groundwater Discharge Site Investigation

In this study, a set of different search strategies for locating submarine groundwater discharge (SGD) are investigated. This set includes pre-defined path planning (PPP), adapted random walk (RW), particle swarm optimisation (PSO), inertia Levy-flight (ILF), self-organising-migration-algorithm (SOMA), and bumblebee search algorithm (BB). The influences of self-localisation and communication errors and limited travel distance of the autonomous underwater vehicles (AUVs) on the performance of the proposed algorithms are investigated. This study shows that the proposed search strategies could not outperform the classic search heuristic based on full coverage path planning if all AUVs followed the same search strategy. In this study, the influence of self-localisation and communication errors was investigated. The simulations showed that, based on the median error of the search runs, the performance of SOMA was in the same order of magnitude regardless the strength of the localisation error. Furthermore, it was shown that the performance of BB was highly affected by increasing localisation errors. From the simulations, it was revealed that all the algorithms, except for PSO and SOMA, were unaffected by disturbed communications. Here, the best performance was shown by PPP, followed by BB, SOMA, ILF, PSO, and RW. Furthermore, the influence of the limited travel distances of the AUVs on the search performance was evaluated. It was shown that all the algorithms, except for PSO, were affected by the shorter maximum travel distances of the AUVs. The performance of PPP increased with increasing maximum travel distances. However, for maximum travel distances > 1800 m the median error appeared constant. The effect of shorter travel distances on SOMA was smaller than on PPP. For maximum travel distances < 1200 m, SOMA outperformed all other strategies. In addition, it can be observed that only BB showed better performances for shorter travel distances than for longer ones. On the other hand, with different search strategies for each AUV, the search performance of the whole swarm can be improved by incorporating population-based search strategies such as PSO and SOMA within the PPP scheme. The best performance was achieved for the combination of two AUVs following PPP, while the third AUV utilised PSO. The best fitness of this combination was 15.9. This fitness was 26.4% better than the performance of PPP, which was 20.4 on average. In addition, a novel mechanism for dynamically selecting a search strategy for an AUV is proposed. This mechanism is based on fuzzy logic. This dynamic approach is able to perform at least as well as PPP and SOMA for different travel distances of AUVs. However, due to the better adaptation to the current situation, the overall performance, calculated based on the fitness achieved for different maximum travel distances, the proposed dynamic search strategy selection performed 32.8% better than PPP and 34.0% better than SOMA.

Connectivity in Superblock Street Networks: Measuring Distance, Directness, and the Diversity of Pedestrian Paths

Superblocks are a common urban development strategy used in cities of the United Arab Emirates and the larger Gulf region. In planning new neighborhoods, these cities utilize superblocks structured using various street network designs. Despite their key role in shaping its main transportation network, the connectivity of these designs has not been frequently studied. This paper addresses this research gap, analyzing ten different superblock designs, and focusing on their internal and external connectivity properties. Internal connectivity is studied by measuring connections between plots in the superblocks. External connectivity is measured from plots to the superblocks’ corners, the points from which to access surrounding areas. Connectivity is measured in terms of distance, directness, and route diversity. The results show that strong similarities exist across the studied designs, particularly in terms of travel distances. Differences are found in terms of efficiency and, most notably, route diversity. Findings are discussed in relation to walkability, the costs associated to each design given network length variations, and the importance of creating rich and diverse street systems that support open-ended exploration. While based on a sample of ideal cases and in need of validation with built cases, this paper outlines a method by which to evaluate and compare superblock network design alternatives.

The wetting properties of frosted glass

Frosted glass is a common, low cost material. Its roughness can be used to control how it is wet by water. In this paper, the wetting properties of silicone oil and water are investigated. For the oil, wetting is total since the oleophilic character of the glass is enhanced by its roughness. Due to the remarkable optical properties of frosted glass, the spreading of oil droplets on its surface was recorded over three months. Frosted glass is a parahydrophilic surface because of its large contact angle hysteresis (up to 80° ). The behaviour of oil and water droplets was compared on a long piece of inclined frosted glass. The trajectories (and the spreading) of the droplets were studied and phenomenological laws were deduced to describe the dependence of the droplet speed on the initial volume of the droplet and the angle of inclination. Such dependences of speed at long travel distances (100 times the capillary length) were deduced and rationalised with a simple model that takes into account the thickness of the wake. Moreover, we analysed the flow inside the wake of water droplets sliding on inclined frosted glass. Suggestions are given on how to exploit drainage of the water droplet wake and the high hysteresis of water within the framework of open microfluidics.

Zero Traffic Conflict (ZTC) Road Networks with Concentric Traffic Paths

U-turns and left turns are sometimes forbidden even though it increases travel distances. The greater travel distances are sometimes outweighed by the improved movement through intersections due to there being fewer conflicting lanes of traffic. One can, further, forbid straight-throughs. Restricting a sufficient number of turns can make intersections free from crossing lanes of traffic (``zero traffic conflict,'' ``ZTC"), though there may still be merging lanes of traffic. It's possible to make \begin{it}all\end{it} intersections in a road \begin{it}network\end{it} ZTC. However, keeping all destinations accessible and travel distances moderate requires careful selection of allowed driving directions and turning directions. We demonstrate through numerical microscopic and macroscopic simulations that there are road networks and ranges of traffic loads for which, in comparison with conventional schemes, ZTC road network can carry approximately $50$\% more vehicular traffic without incurring gridlock.

The implication of street network design for walkability: A review

A street network-friendly design allows walkability among people and is proven beneficial to the environment, community health, and economy of the city. Walkability in a street network increases potential trips by pedestrians through sidewalks and linked streets to create shorter travel distances. Street designs for pedestrian walkways are commonly ignored, with more focus on vehicular access, consequently leading to a lack of effort in improving the street network designs linked to various destinations. Accordingly, this paper reviews the street network designs affecting walkability from the perspective of the urban community. A systematic literature review method was employed to identify and analyse the articles published in the Sciencedirect.com database between 2004 and 2020 using two keywords: street network design and walkable city. The main finding suggested that street networks were associated with proper street designs. Therefore, a walkable city developed from a thriving street network design improved local physical activities and healthy communities.

Hearing Aid Review Appointments: Attendance and Effectiveness

Purpose This study aimed to (a) identify participant factors associated with hearing aid review (HAR) appointment attendance, (b) investigate whether the completion of self-report survey identifying hearing aid–related problems affects HAR appointment attendance, and (c) investigate whether hearing aid problems and hearing aid management deficiencies are adequately addressed during HAR appointments. Method A prospective cohort study of adult hearing aid owners recruited from a single hearing clinic in Western Australia. Potential participants were invited to an annual HAR appointment via postal letter. The invitation included a paper-based self-report survey evaluating either (a) hearing aid problems, (b) hearing aid management skills, or (c) hearing aid outcomes, depending on which intervention/control group the potential participants were assigned to, and a reply paid addressed envelope. Two months later, potential participants were sent all three paper-based self-report surveys, irrespective of whether they had attended or not attended an HAR appointment. Results (a) There was no significant difference in gender or source of funding for hearing services between HAR appointment attendees and nonattendees. HAR nonattendees lived a greater distance from their clinic and were younger than attendees. (b) Survey completion did not influence HAR appointment attendance rates. (c) A significant reduction in individuals' self-reported hearing aid problems was recorded following the attendance at the HAR appointment. No significant changes in hearing aid management skills or overall hearing aid outcomes were detected. Conclusions Long travel distances may be a barrier to attendance at review appointments. HAR appointments appear to be effective in improving hearing aid problems.

Stroke care networks and the impact on quality of care

Lack of rapidly available neurological expertise, especially in rural areas, is one of the key obstacles in stroke care. Stroke care networks attempt to address this challenge by connecting hospitals with specialized stroke centers, stroke units, and hospitals of lower levels of care. While the benefits of stroke care networks are well-documented, travel distances are likely to increase when patients are transferred almost exclusively between members of the same network. This is particularly important for patients who require mechanical thrombectomy, an increasingly employed treatment method that requires equipment and expertise available in specialized stroke centers. This study aims to analyze the performance of the current design of stroke care networks in Bavaria, Germany, and to evaluate the improvement potential when the networks are redesigned to minimize travel distances. To this end, we define three fundamental criteria for assessing network design performance: 1) average travel distances, 2) the populace in the catchment area relative to the number of stroke units, and 3) the ratio of stroke units to lower-care hospitals. We generate several alternative stroke network designs using an analytical approach based on mathematical programming and clustering. Finally, we evaluate the performance of the existing networks in Bavaria via simulation. The results show that the current network design could be significantly improved concerning the average travel distances. Moreover, the existing networks are unnecessarily imbalanced when it comes to their number of stroke units per capita and the ratio of stroke units to lower-care hospitals.

An Analysis between Patient Demographics and Non-attendances in General Surgery Clinics at an NHS Trust: An Audit

Background: Missed clinic appointments can have bearing on a multitude of factors including patient care, hospital management and resources. Aim: To assess the non-attendance rates to surgical clinics within our trust. Secondary outcomes will be to assess the correlation between travel distances to clinic, time of year, patient demographics, and whether the appointment is a new patient or follow-up, on DNA rate. Methods: Retrospective audit including all patients attending outpatient general surgical appointments at all 5 district general hospitals within the trust between the fiscal years of April 2016 to March 2018. Using case notes and electronic patient records, data on patient demographics, type of appointment, time of year and distance from hospital were collected. Results and Conclusions: There is correlation between DNAs and age, gender, ethnicity, subspecialty, and distance from hospital. The reasons behind DNAs will be multifactorial and efforts should be made to investigate the barriers to attendance.

Macroplastic Debris Transfer in Rivers: A Travel Distance Approach

Plastic accumulation in the marine environment is a major concern given the harmful effects and longevity of plastics at sea. Although rivers are likely to significantly contribute to the flux of plastic to marine systems, the behaviour of plastic debris in fluvial systems remains poorly understood and estimates of riverine plastic flux derived from field measurements and modelling efforts are highly uncertain. This paper presents a new probabilistic model of plastic transport in rivers which describes the main processes controlling plastic displacement and which predicts the statistical distribution of travel distances for individual items of buoyant macroplastic debris. Macroplastic transport is controlled by retention in temporary stores (or traps) created by vegetation, bank roughness elements and other obstacles. The behaviour of these traps is represented in the model via a series of Bernoulli trials conducted in a Monte Carlo simulation framework. The model was applied to a tracer experiment in a small 1.1 km river reach. Three replicates were used for calibration and three for validation. For each replicate, 90 closed air-filled polyethylene terephthalate (PET) bottles were introduced at the upstream end of the reach and the location of each bottle was recorded after 24 h. Bottles were chosen as “model” macroplastic litter items given their high usage and littering rate. Travel distances were low. The average and maximum distances travelled over 24 h were 231 m and 1.1 km, respectively. They were also variable. The coefficient of variation of travel distances was 0.94. Spatial patterns were controlled by the location and characteristics of discrete traps. The model was able to describe the observed travel distance distributions reasonably well, suggesting that modelling plastic behaviour in longer reaches and even whole catchments using a stochastic travel distance approach is feasible. The approach has the potential to improve estimates of river plastic flux, although significant knowledge gaps remain (e.g., the rate and location of plastic supply to river systems, the transport behaviours of different types of plastic debris and trap effectiveness in different types of river system, season, and discharge).