Design of Field Experiments for Adaptive Sampling of the Ocean with Autonomous Vehicles

Due to the highly non-linear and dynamical nature of oceanic phenomena, the predictive capability of various ocean models depends on the availability of operational data. A practical method to improve the accuracy of the ocean forecast is to use a data assimilation methodology to combine in-situ measured and remotely acquired data with numerical forecast models of the physical environment. Autonomous surface and underwater vehicles with various sensors are economic and efficient tools for exploring and sampling the ocean for data assimilation; however there is an energy limitation to such vehicles, and thus effective resource allocation for adaptive sampling is required to optimize the efficiency of exploration. In this paper, we use physical oceanography forecasts of the coastal zone of Singapore for the design of a set of field experiments to acquire useful data for model calibration and data assimilation. The design process of our experiments relied on the oceanography forecast including the current speed, its gradient, and vorticity in a given region of interest for which permits for field experiments could be obtained and for time intervals that correspond to strong tidal currents. Based on these maps, resources available to our experimental team, including Autonomous Surface Craft (ASC) are allocated so as to capture the oceanic features that result from jets and vortices behind bluff bodies (e.g., islands) in the tidal current. Results are summarized from this resource allocation process and field experiments conducted in January 2009.Singapore. National Research Foundatio

Simulation of Internal Undular Bores Propagating over a Slowly Varying Region

Internal undular bores have been observed in many parts of the world. Studies have shown that many marine structures face danger and risk of destruction caused by internal undular bores due to the amount of energy it carries. This paper looks at the transformation of internal undular bore in two-layer fluid flow under the influence of variable topography. Thus, the surface of the bottom is considered to be slowly varying. The appropriate mathematical model is the variable-coefficient extended Korteweg-de Vries equation. We are particularly interested in looking at the transformation of KdV-type and table-top undular bore over the variable topography region. The governing equation is solved numerically using the method of lines, where the spatial derivatives are first discretised using finite difference approximation so that the partial differential equation becomes a system of ordinary differential equations which is then solved by 4th order Runge-Kutta method. Our numerical results show that the evolution of internal undular bore over different types of varying depths regions leads to a number of adiabatic and non-adiabatic effects. When the depth decreases slowly, a solitary wavetrain is observed at the front of the transformed internal undular bore. On the other hand, when the depth increases slowly, we observe the generation of step-like wave and weakly nonlinear trailing wavetrain, the occurrence of multi-phase behaviour, the generation of transformed undular bore of negative polarity and diminishing transformed undular bore depending on the nature of the topography after the variable topography

The effect of strategy game types on inhibition

YesPast studies have shown evidence of transfer of learning in action video games, less so in other types e.g. strategy games. Further, the transfer of learning from games to inhibitory control has yet to be examined from the perspectives of time constraint and logic contradiction. We examined the effect of strategy games (puzzle, turn-based strategy ‘TBS’, real-time strategy ‘RTS’) on inhibition (response inhibition and distractor inhibition) and cerebral hemispheric activation over four weeks. We predicted that compared to RTS, puzzle and TBS games would (1) improve response and distractor inhibition, and (2) increase cerebral hemispheric activation demonstrating increased inhibitory control. A total of 67 non-habitual video game players (Mage = 21.63 years old, SD = 2.12) played one of three games; puzzle (n = 19), TBS (n = 24) or RTS (n = 24) for four weeks on their smartphones. Participants completed three inhibition tasks, working memory (WM), and had their tympanic membrane temperature (TMT) taken from each ear before and after playing the games. Results showed that only the puzzle game group showed an improved response inhibition while controlling for WM. There were no significant changes in the distractor inhibition tasks. We also found that there was an increase in left TMT while playing RTS, suggesting the presence of increased impulsivity in RTS. Our findings suggest that puzzle games involving logical contradiction could improve response inhibition, showing potential as a tool for inhibition training.Newton Fund Institutional Links grant ID: 331745333, under Newton-Ungku Omar Fund partnership. The grant is funded by the UK Department for Business, Energy and Industrial Strategy and Malaysian Industry-Government Group for High Technology (MIGHT) and delivered by the British CouncilResearch Development Fund Publication Prize Award winner, Dec 2021

Multi-layer model simulation and data assimilation in the Serangoon Harbor of Singapore

In June of 2009, a sea trial was carried out around Singapore to study and monitor physical, biological and chemical oceanographic parameters. Temperature, salinity and velocities were collected from multiple vehicles. The extensive data set collected in the Serangoon Harbour provides an opportunity to study barotropic and baroclinic circulation in the harbour and to apply data assimilation methods in the estuarine area. In this study, a three-dimensional, primitive equation coastal ocean model (FVCOM) with a number of vertical layers is used to simulate barotropic and baroclinic flows and reconstruct the vertical velocity structures. The model results are validated with in situ ADCP observations to assess the realism of the model simulations. EnKF data assimilation method is successively implemented to assimilate all the available ADCP data, and thus correct for the model forecast deficiencies.Singapore. National Research FoundationSingapore-MIT AllianceSingapore-MIT Alliance. Center for Environmental Sensing and Monitorin

Infrastructure for mobile sensor network in the Singapore coastal zone

URL to conference page. Scroll down to 2010 conference, click on "Paper and session list," and search the PDF for Patrikalakis.Singapore is an island nation located at southern tip of the Malaysian Peninsula. She is at a strategic location along major shipping routes and therefore has one of the busiest harbors in the world. Having a safe and secure harbor environment is vital to maintain trade and growth in the country and region. To help build and maintain a safe harbor environment, the Center of Environmental Sensing and Modelling (CENSAM) under the Singapore-MIT Alliance for Research and Technology (SMART) is developing a mobile sensor network in the Singapore coastal zone

The Effect of Acidic to the Fly Ash Based Geopolymer Artificial Aggregate

Abstract: The Ordinary Portland Cement (OPC), which is widely used materials not only consumes significant amount of natural resources and energy but also pollutes the atmosphere by the emission of CO 2 . Hence, reduce this ill effect, the search for alternative result is geopolymer concrete. This experiment research focused on utilizing fly ash as source material. Fly ash is receiving more attention now since their uses generally improve the properties in construction industry, cost saving and reduction of negative environmental affects. Three different molarity of paste has been tested to acidic environment to determine the effect of acidic to the fly ash based geopolymer artificial aggregate. The geopolymer paste samples were cured at 70°C for 1 day and keep in room temperature until the testing days. The compressive strength and acid resistant testing was done at after 28 days. The result showed that the geopolymer paste with NaOH concentration of 12 M produced maximum strength

The Therapeutic Evaluation of Steroids in IgA Nephropathy Global (TESTING) Study: Trial Design and Baseline Characteristics

INTRODUCTION: Despite optimal current care, up to 30% of individuals suffering from immunoglobulin A nephropathy (IgAN) will develop kidney failure requiring dialysis or kidney transplantation. The Therapeutic Evaluation of STeroids in IgA Nephropathy Global (TESTING) study was designed to assess the benefits and risks of steroids in people with IgAN. We report the trial design as well as the baseline characteristics of study participants. METHODS: It is an investigator-initiated, multicenter, double-blind, placebo-controlled, randomized trial of individuals with kidney biopsy-confirmed IgAN, proteinuria ≥1 g/day, and an estimated GFR of 20-120 mL/min/1.73 m2, following at least 3 months of standard of care including maximum labelled (or tolerated) dose of renin-angiotensin system blockade. The original study design randomized participants 1:1 to oral methylprednisolone (0.6-0.8 mg/kg/day, maximum 48 mg/day) for 2 months, with subsequent weaning by 8 mg/day/month over 6-8 months, or matching placebo. The intervention was modified in 2016 (due to an excess of serious infection) to low-dose methylprednisolone (0.4 mg/kg/day, maximum 32 mg/day) for 2 months, followed by weaning by 4 mg/day/month over 6-9 months, or matching placebo. Participants recruited after 2016 also received prophylaxis against Pneumocystis jirovecii pneumonia during the first 12 weeks of treatment. RESULTS: The study recruitment period extended from May 2012 to November 2019. By the time the excess of serious infections was observed, 262 participants had been randomized to the original full-dose treatment algorithm, and an interim analysis was reported in 2016. Subsequently, 241 additional participants were randomized to a revised low-dose protocol, for a total of 503 participants from China (373), India (78), Canada (24), Australia (18), and Malaysia (10). The mean age of randomized participants was 38, 39% were female, mean eGFR at randomization was 62.7 mL/min/1.73 m2, and mean 24-h urine protein 2.54 g. The primary endpoint is a composite of 40% eGFR decline from baseline or kidney failure (dialysis, transplantation, or death due to kidney disease), and participants will be followed until the primary outcome has been observed in at least 160 randomized participants. Analyses will also be made across predefined subgroups. Effects on eGFR slope and albuminuria will also be assessed overall, as well as by the steroid dosing regimen. CONCLUSIONS: The TESTING study (combined full and low dose) will define the benefits of corticosteroid use on major kidney outcomes, as well as the risks of therapy, and provide data on the relative effects of different doses, in individuals with high-risk IgAN

The Therapeutic Evaluation of Steroids in IgA Nephropathy Global (TESTING) Study: Trial Design and Baseline Characteristics

Introduction: Despite optimal current care, up to 30% of individuals suffering from immunoglobulin A nephropathy (IgAN) will develop kidney failure requiring dialysis or kidney transplantation. The Therapeutic Evaluation of STeroids in IgA Nephropathy Global (TESTING) study was designed to assess the benefits and risks of steroids in people with IgAN. We report the trial design as well as the baseline characteristics of study participants. Methods: It is an investigator-initiated, multicenter, double-blind, placebo-controlled, randomized trial of individuals with kidney biopsy-confirmed IgAN, proteinuria ≥1 g/day, and an estimated GFR of 20-120 mL/min/1.73 m2, following at least 3 months of standard of care including maximum labelled (or tolerated) dose of renin-angiotensin system blockade. The original study design randomized participants 1:1 to oral methylprednisolone (0.6-0.8 mg/kg/day, maximum 48 mg/day) for 2 months, with subsequent weaning by 8 mg/day/month over 6-8 months, or matching placebo. The intervention was modified in 2016 (due to an excess of serious infection) to low-dose methylprednisolone (0.4 mg/kg/day, maximum 32 mg/day) for 2 months, followed by weaning by 4 mg/day/month over 6-9 months, or matching placebo. Participants recruited after 2016 also received prophylaxis against Pneumocystis jirovecii pneumonia during the first 12 weeks of treatment. Results: The study recruitment period extended from May 2012 to November 2019. By the time the excess of serious infections was observed, 262 participants had been randomized to the original full-dose treatment algorithm, and an interim analysis was reported in 2016. Subsequently, 241 additional participants were randomized to a revised low-dose protocol, for a total of 503 participants from China (373), India (78), Canada (24), Australia (18), and Malaysia (10). The mean age of randomized participants was 38, 39% were female, mean eGFR at randomization was 62.7 mL/min/1.73 m2, and mean 24-h urine protein 2.54 g. The primary endpoint is a composite of 40% eGFR decline from baseline or kidney failure (dialysis, transplantation, or death due to kidney disease), and participants will be followed until the primary outcome has been observed in at least 160 randomized participants. Analyses will also be made across predefined subgroups. Effects on eGFR slope and albuminuria will also be assessed overall, as well as by the steroid dosing regimen. Conclusions: The TESTING study (combined full and low dose) will define the benefits of corticosteroid use on major kidney outcomes, as well as the risks of therapy, and provide data on the relative effects of different doses, in individuals with high-risk IgAN