359,652 research outputs found
Fully Distributed Cooperative Spectrum Sensing for Cognitive Radio Networks
Cognitive radio networks (CRN) sense spectrum occupancy and manage themselves to operate in unused bands without disturbing licensed users. The detection capability of a radio system can be enhanced if the sensing process is performed jointly by a group of nodes so that the effects of wireless fading and shadowing can be minimized. However, taking a collaborative approach poses new security threats to the system as nodes can report false sensing data to force a wrong decision. Providing security to the sensing process is also complex, as it usually involves introducing limitations to the CRN applications. The most common limitation is the need for a static trusted node that is able to authenticate and merge the reports of all CRN nodes. This paper overcomes this limitation by presenting a protocol that is suitable for fully distributed scenarios, where there is no static trusted node
Activities of the Pilot Land Data System project
The University of Maryland's Remote Sensing Systems Laboratory submitted to NASA/Goddard an interim progress report on the work being conducted within its Pilot Land Data System IPLDS project. The Remote Sensing Systems Laboratory addressed the following tasks: (1) identify data types and data sources needed to describe the selected test sites in collaboration with Goddard's Hydrological Sciences Branch; (2) define the procedures necessary to access/acquire this data; (3) conduct meetings with the PLDS Systems Engineering Group to identify functional specification priorities for PLDS development; (4) assemble documentation on historical remotely sensed imagery and transfer of such information to the PLDS Data Management Group; (5) collect data identified by Goodard's Hydrological Sciences Branch for data set inventory in PLD; (6) develop a Workstation-PLDS system interface over high speed lines, (7) develop and test through a Phase 1 demonstration of a micro workstation to access PLDS; and (8) establish interdepartmental agreement of development of computer link for electronic access of water resources data from USGS
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Monolithic optofluidic chips: from optical manipulation of single cells to quantum sensing of fluids
This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.We report on a new class of integrated optofluidic devices, fabricated by femtosecond laser
micromachining. The capability to combine optical waveguides with microfluidic channels in the same
glass chip provides a very powerful platform, introducing new tools in the field of optical sensing. Two
recent applications that greatly benefitted from this novel technology are on-chip optical manipulation of
single cells by optical forces and optical sensing of the refractive index of fluids by quantum states of light.
The specific properties of robustness, alignment free and portability of these devices pave the way to the use
of these advanced sensing technologies outside the lab, in a real application environment
Review on bibliography related to antimicrobials
In this report, a bibliographic research has been done in the field of antimicrobials.In this report, a bibliographic research has been done in the field of antimicrobials. Not all antimicrobials have been included, but those that are being subject of matter in the group GBMI in Terrassa, and others of interest. It includes chitosan and other biopolymers. The effect of nanoparticles is of great interest, and in this sense, the effect of Ag nanoparticles and antibiotic nanoparticles (nanobiotics) has been revised. The report focuses on new publications and the antimicrobial effect of peptides has been considered. In particular, the influence of antimicrobials on membranes has deserved much attention and its study using the Langmuir technique, which is of great utility on biomimetic studies. The building up of antimicrobials systems with new techniques (bottom-up approach), as the Layer-by-Layer technique, can also be found in between the bibliography. It has also been considered the antibiofilm effect, and the new ideas on quorem sensing and quorum quenching.Preprin
Investigation into Wheelchair Mobility Control that Uses a Minimally Invasive Intra-Oral Palate Control Device utilising Resistopalatography Techniques
Interfacing with conventional wheelchair input devices is a major challenge when it comes to patients with high levels of disability. This paper intends to report on the new method of wheelchair mobility interfacing using Resistopalatog- raphy. The technique proposed here is based around utilising the tongue as the controlling muscle group to input desired movement into a force sensitive sensing dental retainer. Using the position of the force, and force applied a direction and speed metric can be calculated emulating conventional joystick output data. The resistopalatography technique has been applied to other Human Machine Interfacing areas with success [1]
Harnessing Remote Sensing to Accomplish Full Carbon Accounting: Workshop Report
The workshop "Harnessing Remote Sensing to Accomplish Full Carbon Accounting" was held on December 9-11th, 1999 at IIASA with the intention of meeting the following objectives:
(1) To Promote the mutual interests of remote sensing and carbon science communities by exchanging the ideas regarding the requirements for carbon accounting and the current available products derived from remote sensing land information systems;
(2) To produce strategic recommendations on how to improve FCA at different scales with the use of remote sensing tools; and,
(3) To develop a Framework to Apply Recommendations for Sub-global and National-Level Case Studies.
Although these ambitious targets were only part met, three discussion group sessions resulted in describing: What is required to implement full carbon accounting; How remote sensing can be used to assist this implementation; and, How remote sensing can be used to reduce the uncertainties related to FCA.
This report summarizes the presentations, discussions and results of this workshop and outlines the next steps to be taken by IIASA
On Link Estimation in Dense RPL Deployments
The Internet of Things vision foresees billions of
devices to connect the physical world to the digital world. Sensing
applications such as structural health monitoring, surveillance or
smart buildings employ multi-hop wireless networks with high
density to attain sufficient area coverage. Such applications need
networking stacks and routing protocols that can scale with
network size and density while remaining energy-efficient and
lightweight. To this end, the IETF RoLL working group has
designed the IPv6 Routing Protocol for Low-Power and Lossy
Networks (RPL). This paper discusses the problems of link quality
estimation and neighbor management policies when it comes
to handling high densities. We implement and evaluate different
neighbor management policies and link probing techniques in
Contiki’s RPL implementation. We report on our experience
with a 100-node testbed with average 40-degree density. We show
the sensitivity of high density routing with respect to cache sizes
and routing metric initialization. Finally, we devise guidelines for
design and implementation of density-scalable routing protocols
Lattice Induced Transparency in Metasurfaces
Lattice modes are intrinsic to the periodic structures and their occurrence
can be easily tuned and controlled by changing the lattice constant of the
structural array. Previous studies have revealed excitation of sharp absorption
resonances due to lattice mode coupling with the plasmonic resonances. Here, we
report the first experimental observation of a lattice induced transparency
(LIT) by coupling the first order lattice mode (FOLM) to the structural
resonance of a metamaterial resonator at terahertz frequencies. The observed
sharp transparency is a result of the destructive interference between the
bright mode and the FOLM mediated dark mode. As the FOLM is swept across the
metamaterial resonance, the transparency band undergoes large change in its
bandwidth and resonance position. Besides controlling the transparency
behaviour, LIT also shows a huge enhancement in the Q-factor and record high
group delay of 28 ps, which could be pivotal in ultrasensitive sensing and slow
light device applications.Comment: 5 figure
Photonic-chip-based tunable slow and fast light via stimulated Brillouin scattering
We report the first (to our knowledge) demonstration of photonic chip based tunable slow and fast light via stimulated Brillouin scattering. Slow, fast, and negative group velocities were observed in a 7 cm long chalcogenide (As2S3) rib waveguide with a group index change ranging from ∼−44 to +130, which results in a maximum delay of ∼23 ns at a relatively low gain of ∼23 dB. Demonstration of large tunable delays in a chip scale device opens up applications such as frequency sensing and true-time delay for a phased array antenna, where integration and delays ∼10 ns are highly desirable
Remote Sensing at the Horace Cabe Site (41BW14)
A magnetometer survey was conducted at the Horace Cabe Mound site (41BW14) in 2005 by Walker and Schultz as part of the Bowie County Levee Realignment project in Bowie County, Texas. The purpose of the survey was to attempt to locate anomalies that may represent potential archaeological features at this important Late Caddo mound center near the Red River. The area was surveyed using a Geometrics portable G858 cesium sensor magnetometer and a G-856 proton magnetometer base station. This article puts on record another substantive example of Caddo archaeology as seen through the use of remote sensing technology.
The original processing and interpretation of this data presented in Sundermeyer et al. are not simply re-hashed here. Further data processing has revealed several possible Caddo structures on and in the immediate vicinity of Mounds B and C at the Cabe site
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