10,689 research outputs found
Oceans of Tomorrow sensor interoperability for in-situ ocean monitoring
The Oceans of Tomorrow (OoT) projects,
funded by the European Commission’s FP7 program, are
developing a new generation of sensors supporting physical,
biogeochemical and biological oceanographic monitoring.
The sensors range from acoustic to optical fluorometers to
labs on a chip. The result is that the outputs are diverse in a
variety of formats and communication methodologies. The
interfaces with platforms such as floats, gliders and cable
observatories are each different. Thus, sensorPeer ReviewedPostprint (author's final draft
Monte Carlo model of the uncertainty of SEA loss factors
Finite Element Methods are widely used to model vibro-acoustic systems, but as the modal density becomes higher this type of model becomes inaccurate and impractical. This is why in the high modal density region the use of Statistical Energy Analysis (SEA) models has become increasingly popular. SEA has some obvious advantages such as its simple formal expression, being based on linear equation systems or the reduced number of variables involved. But SEA has drawbacks as well, such as the absence of local information or the necessity of frequency averaging. A key quantity in SEA models is the loss factor. This takes into account the energy dissipated within a given subsystem or when power flows from one subsystem to another. Even though analytical expressions exist for a number of subsystems of differing nature, the measurement of the loss factor is still advisable and a necessity for a large number of cases. The most commonly used method of measuring loss factors is the Power Injection Method. This method is based on the injection of power into every single subsystem in sequence while the energy in each subsystem is measured. In spite of its simplicity, there remain a number of problems where the accuracy of the results is influenced by various practical issues. In this paper, a Monte Carlo model is used to describe the uncertainty of a two subsystemproblem consisting of two planar elements connected along one side. The influence of the input variables is studied and the conditioning of the coefficient matrix that model the system is also taken into accoun
Decentralized Wastewater Treatment Plant in Bangalore, India
The Vrishabawathi River in Bangalore, India, has high levels of pollution due to untreated wastewater discharges from the city. The city requires significant expansion of its wastewater treatment infrastructure. Smaller-capacity plants spread throughout the city, known as decentralized treatment plants, provide an alternative to centralized treatment plants that can meet these demands. This project involved the design of one decentralized plant. This plant is located in the Kengeri district of the city, a mostly residential area in the outskirts of Bangalore. The designed treatment facility includes two primary clarifiers, two biotowers, and two secondary clarifiers. Plants like these can help solve Bangalore’s environmental and water resource difficulties
Linkage, whole genome sequence, and biological data implicate variants in RAB10 in Alzheimer’s disease resilience
Recommended from our members
Oxylipins in triglyceride-rich lipoproteins of dyslipidemic subjects promote endothelial inflammation following a high fat meal.
Elevated triglyceride-rich lipoproteins (TGRL) in circulation is a risk factor for atherosclerosis. TGRL from subjects consuming a high saturated fat test meal elicited a variable inflammatory response in TNFα-stimulated endothelial cells (EC) that correlated strongly with the polyunsaturated fatty acid (PUFA) content. This study investigates how the relative abundance of oxygenated metabolites of PUFA, oxylipins, is altered in TGRL postprandially, and how these changes promote endothelial inflammation. Human aortic EC were stimulated with TNFα and treated with TGRL, isolated from subjects' plasma at fasting and 3.5 hrs postprandial to a test meal high in saturated fat. Endothelial VCAM-1 surface expression stimulated by TNFα provided a readout for atherogenic inflammation. Concentrations of esterified and non-esterified fatty acids and oxylipins in TGRL were quantified by mass spectrometry. Dyslipidemic subjects produced TGRL that increased endothelial VCAM-1 expression by ≥35%, and exhibited impaired fasting lipogenesis activity and a shift in soluble epoxide hydrolase and lipoxygenase activity. Pro-atherogenic TGRL were enriched in eicosapentaenoic acid metabolites and depleted in esterified C18-PUFA-derived diols. Abundance of these metabolites was strongly predictive of VCAM-1 expression. We conclude the altered metabolism in dyslipidemic subjects produces TGRL with a unique oxylipin signature that promotes a pro-atherogenic endothelial phenotype
Applying OGC sensor web enablement to ocean observing systems
The complexity of marine installations
for ocean observing systems has grown significantly in
recent years. In a network consisting of tens, hundreds
or thousands of marine instruments, manual
configuration and integration becomes very
challenging. Simplifying the integration process in
existing or newly established observing systems would
benefit system operators and is important for the
broader application of different sensors. This article
presents an approach for the automatic configuration
and integration of sensors into an interoperable
Sensor Web infrastructure. First, the sensor
communication model, based on OGC's SensorML
standard, is utilized. It serves as a generic driver
mechanism since it enables the declarative and
detailed description of a sensor's protocol. Finally, we
present a data acquisition architecture based on the
OGC PUCK protocol that enables storage and
retrieval of the SensorML document from the sensor
itself, and automatic integration of sensors into an
interoperable Sensor Web infrastructure. Our
approach adopts Efficient XML Interchange (EXI) as
alternative serialization form of XML or JSON. It
solves the bandwidth problem of XML and JSON.Peer ReviewedPostprint (author's final draft
Non-Myopic Sensor Control for Target Search and Track Using a Sample-Based GOSPA Implementation
This paper is concerned with sensor management for target search and track
using the generalised optimal subpattern assignment (GOSPA) metric. Utilising
the GOSPA metric to predict future system performance is computationally
challenging, because of the need to account for uncertainties within the
scenario, notably the number of targets, the locations of targets, and the
measurements generated by the targets subsequent to performing sensing actions.
In this paper, efficient sample-based techniques are developed to calculate the
predicted mean square GOSPA metric. These techniques allow for missed
detections and false alarms, and thereby enable the metric to be exploited in
scenarios more complex than those previously considered. Furthermore, the GOSPA
methodology is extended to perform non-myopic (i.e. multi-step) sensor
management via the development of a Bellman-type recursion that optimises a
conditional GOSPA-based metric. Simulations for scenarios with missed
detections, false alarms, and planning horizons of up to three time steps
demonstrate the approach, in particular showing that optimal plans align with
an intuitive understanding of how taking into account the opportunity to make
future observations should influence the current action. It is concluded that
the GOSPA-based, non-myopic search and track algorithm offers a powerful
mechanism for sensor management.Comment: The paper has been submitted for publication in IEEE Transactions on
Aerospace and Electronic Systems and is currently in revie
Air gap influence on the vibro-acoustic response of Solar Arrays during launch
One of the primary elements on the space missions is the electrical power subsystem, for which the critical component is the solar array. The behaviour of these elements during the ascent phase of the launch is critical for avoiding damages on the solar panels, which are the primary source of energy for the satellite in its final configuration. The vibro-acoustic response to the sound pressure depends on the solar array size, mass, stiffness and gap thickness. The stowed configuration of the solar array consists of a multiple system composed of structural elements and the air layers between panels. The effect of the air between panels on the behaviour of the system affects the frequency response of the system not only modifying the natural frequencies of the wings but also as interaction path between the wings of the array. The usual methods to analyze the vibro-acoustic response of structures are the FE and BE methods for the low frequency range and the SEA formulation for the high frequency range. The main issue in the latter method is, on one hand, selecting the appropriate subsystems, and, on the other, identifying the parameters of the energetic system: the internal and coupling loss factors. From the experimental point of view, the subsystems parameters can be identified by exciting each subsystem and measuring the energy of all the subsystems composing the Solar Array. Although theoretically possible, in practice it is difficult to apply loads on the air gaps. To analyse this situation, two different approaches can be studied depending on whether the air gaps between the panels are included explicitly in the problem or not. For a particular case of a solar array of three wings in stowed configuration both modelling philosophies are compared. This stowed configuration of a three wing solar arrays in stowed configuration has been tested in an acoustic chamber. The measured data on the solar wings allows, in general, determining the loss factors of the configuration. The paper presents a test description and measurements on the structure, in terms of the acceleration power spectral density. Finally, the performance of each modelling technique has been evaluated by comparison between simulations with experimental results on a spacecraft solar array and the influence on the apparent properties of the system in terms of the SEA loss factors has been analyse
- …