421 research outputs found
Comparison of 3D scanned human models for off-body communications using motion capture
Body area networks are complex to analyze as there are several channel mechanisms occurring simultaneously, i.e. environmental multipath together with body motion and close coupling between worn antennas and human tissue. Electromagnetic (EM) simulation is an important tool since not all studies can be done on a real human. In order to gain insight into off-body communication involving a worn antenna, this paper uses a 3D animated model obtained from a 3D surface scanner and a motion capture system for full wave simulation of channels at 2.45 and 5.5GHz. To evaluate if the model can represent body area radio channels in general, a comparison of S21 of the simulated model with measurements from 5 other models of similar height to the main test subject is presented
Highly efficient Localisation utilising Weightless neural systems
Efficient localisation is a highly desirable property for an autonomous navigation system. Weightless neural networks offer a real-time approach to robotics applications by reducing hardware and software requirements for pattern recognition techniques. Such networks offer the potential for objects, structures, routes and locations to be easily identified and maps constructed from fused limited sensor data as information becomes available. We show that in the absence of concise and complex information, localisation can be obtained using simple algorithms from data with inherent uncertainties using a combination of Genetic Algorithm techniques applied to a Weightless Neural Architecture
Passive wireless tags for tongue controlled assistive technology interfaces
Tongue control with low profile, passive mouth tags is demonstrated as a human–device interface by communicating values of tongue-tag
separation over a wireless link. Confusion matrices are provided to demonstrate user accuracy in targeting by tongue position. Accuracy is
found to increase dramatically after short training sequences with errors falling close to 1% in magnitude with zero missed targets. The
rate at which users are able to learn accurate targeting with high accuracy indicates that this is an intuitive device to operate. The
significance of the work is that innovative very unobtrusive, wireless tags can be used to provide intuitive human–computer interfaces
based on low cost and disposable mouth mounted technology. With the development of an appropriate reading system, control of assistive
devices such as computer mice or wheelchairs could be possible for tetraplegics and others who retain fine motor control capability of
their tongues. The tags contain no battery and are intended to fit directly on the hard palate, detecting tongue position in the mouth with
no need for tongue piercings
Inkjet Fabrication of Frame Dipole FSS
Digital fabrication techniques gives the possibility of producing elements with very thin and precise features which could allow the modification of UHF structures to reduce ink usage while still achieving similar performance. This paper investigates the case where dipole elements are modified into Frame Dipoles by removing areas where the surface current tends to be very low
Inkjet printed paper based frequency selective surfaces and skin mounted RFID tags: the interrelation between silver nanoparticle ink, paper substrate and low temperature sintering technique
Inkjet printing of functional frequency selective surfaces (FSS) and radio frequency identification (RFID) tags on commercial paper substrates using silver nanoparticle inks sintered using low temperature thermal, plasma and photonic techniques is reported. Printed and sintered FSS devices demonstrate performances which achieve wireless communication requirements having a forward transmission scattering parameter, S21, depth greater than ?20 dB at 13 GHz. Printed and plasma sintered RFID tags on transfer paper, which are capable of being mounted on skin, improved read distances compared to previously reported single layer transfer RFID tags fabricated by conventional thermal sintering
The shear-driven Rayleigh problem for generalised Newtonian fluids
We consider a variant of the classical ‘Rayleigh problem’ (‘Stokes’s first problem’) in which a semi-infinite region of initially quiescent fluid is mobilised by a shear stress applied suddenly to its boundary. We show that self-similar solutions for the fluid velocity are available for any generalised Newtonian fluid, regardless of its constitutive law. We demonstrate how these solutions may be used to provide insight into some generic questions about the behaviour of unsteady, non-Newtonian boundary layers, and in particular the effect of shear thinning or thickening on the thickness of a boundary layer
Using A One-Class Compound Classifier To Detect In-Vehicle Network Attacks
The Controller Area Network (CAN) in vehicles provides serial communication between electronic control units that manage en- gine, transmission, steering and braking. Researchers have recently demonstrated the vulnerability of the network to cyber-attacks which can manipulate the operation of the vehicle and compromise its safety. Some proposals for CAN intrusion detection systems, that identify attacks by detecting packet anomalies, have drawn on one-class classi cation, whereby the system builds a decision surface based on a large number of normal instances. The one-class approach is discussed in this paper, together with initial results and observations from implementing a classi er new to this eld. The Compound Classier has been used in image processing and medical analysis, and holds advantages that could be relevant to CAN intrusion detection.<br/
Statics and dynamics of single DNA molecules confined in nanochannels
The successful design of nanofluidic devices for the manipulation of biopolymers requires an understanding of how the predictions of soft condensed matter physics scale with device dimensions. Here we present measurements of DNA extended in nanochannels and show that below a critical width roughly twice the persistence length there is a crossover in the polymer physics
Factor Market Rivalry, Factor Market Myopia, and Strategic Blind Spots: The Case Of The Truck Driver Labor Market
This article explores the relationships among factor market rivalry, factor market myopia, and strategic blind spots in the context of the labor market for truck drivers. Levitt (1960) developed the concept of market myopia to explain how managers often overlooked key competitors in product markets. Trucking managers might do the same thing in looking at competition for truck drivers. Factor market myopia and strategic blind spots help to explain how this happens, and how it becomes more severe in the context of factor market rivalry. In the trucking industry, factor market myopia and strategic blind spots may mean that managers overlook competition for workers who not only can drive trucks, but can also do many other jobs. We find that the labor market for truck drivers offers important lessons on the practical and theoretical ways in which these ideas interact
Significant Factors in the Inkjet Manufacture of Frequency Selective Surfaces
Additive fabrication of electromagnetic structures by inkjet printing technology is both cost effective and compatible with a wide range environmentally-friendly substrates, enabling fabrication of frequency selective surface arrays with line dimensions less than 0.1 mm; difficult to achieve with conventional subtractive techniques. Several approaches have been investigated in order to produce low-cost frequency selective panels with acceptable level of isolation, such as savings in ink by depositing it at the edges of dipole elements where the surface current tends to maximize. The FSS transmission characteristics were improved by jetting multiple ink layers on the whole elements and at the edges. The electrical resistance of various arrays have been measured and analysed and has been used to assess the performances of the FSS
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