Search results for "key"
showing 10 items of 1962 documents
Social Perceptions and Attitudes Towards Climate Change in Poland and in Turkey
2017
Climate change is perceived as a threat to future human well-being and a challenge to sustainable development of local communities and economies world-wide. While some countries and regions are expected to experience slight gains from the climatic changes the other are exposed to major losses. Ever more frequent natural disasters come as warning symptoms of the changes. However, for the sake of effective and efficient adaptation in various world regions answers to the following questions are important: do people notice this changes, do they experience their negative effects, are they satisfied with the climate change mitigation and adaptation actions taken by the governments, are they willi…
Performance Analysis of Cooperative Communication Systems with Imperfect Channel Estimation
2009
This paper investigates the effects of channel estimation errors on the symbol-error-rate (SER) performance of a cooperative communication system operating in an amplify-and- forward (AF) mode. A pilot symbol assisted modulation scheme with linear minimum mean square estimation (LMMSE) is used for the channel estimation. An accurate and easy-to-evaluate SER expression is presented for uncoded cooperative communication systems with quadrature amplitude modulation (QAM) and phase-shift keying (PSK) constellations. Numerical simulations are conducted to verify the correctness of the proposed analytical formulation. It is shown that the performance loss caused by channel estimation errors incre…
Neutrino transport in coherent quasiparticle approximation
2012
We introduce the coherent quasiparticle approximation (cQPA), a model in thermal quantum field theory which describes various effects of temporally varying thermal medium on particle propagation. We present the cQPA Feynman rules and develop related calculational tools. Using these methods we calculate neutrino self energies in the Standard Model and derive an equation of motion for neutrino propagation in a very general framework. Some immediate implications of this equation are discussed. (More detailed abstract in the PDF file.)
Does brick size matter? Albert G. Keller on another QWERTY story
2023
In his seminal ‘‘Clio and the Economics of Qwerty’’, Paul David indicates Thorstein Veblen’s famous discussion of the British system of coal rail haulage as an intellectual antecedent to the idea of lock in. This note documents how Albert G. Keller, a Yale sociologist contemporary of Veblen, had presented a similar argument in connection to the establishment of a brick tax in England and its effects on the size of bricks. Like Veblen, Keller used this illustration to emphasize the inertia exercised by certain institutional conditions.
Molecular topology as a novel approach for drug discovery
2012
Molecular topology (MT) has emerged in recent years as a powerful approach for the in silico generation of new drugs. One key part of MT is that, in the process of drug design/discovery, there is no need for an explicit knowledge of a drug's mechanism of action unlike other drug discovery methods.In this review, the authors introduce the topic by explaining briefly the most common methodology used today in drug design/discovery and address the most important concepts of MT and the methodology followed (QSAR equations, LDA, etc.). Furthermore, the significant results achieved, from this approach, are outlined and discussed.The results outlined herein can be explained by considering that MT r…
The ridge in proton-proton collisions at the LHC
2010
We show that the key features of the CMS result on the ridge correlation seen for high multiplicity events in sqrt(s)=7TeV proton-proton collisions at the LHC can be understood in the Color Glass Condensate framework of high energy QCD. The same formalism underlies the explanation of the ridge events seen in A+A collisions at RHIC, albeit it is likely that flow effects may enhance the magnitude of the signal in the latter.
Fiber Interferometers for Time-domain Quantum Optics
2021
A novel method for stabilizing fiber interferometers based on frequency- and polarization-multiplexing enables unambiguous phase retrieval, long-term stability, and phase-independent performance. These capabilities allow for precise manipulation of time-bin quantum states in a low-complexity setup.
Activating remote entanglement in a quantum network by local counting of identical particles
2019
Quantum information and communication processing within quantum networks usually employs identical particles. Despite this, the physical role of quantum statistical nature of particles in large-scale networks remains elusive. Here, we show that just the indistinguishability of fermions makes it possible a new mechanism of entanglement transfer in many-node quantum networks. This process activates remote entanglement among distant sites, which do not share a common past, by only locally counting identical particles and classical communication. These results constitute the key achievement of the present technique and open the way to a more stable multistage transfer of nonlocal quantum correl…
Human body sensing: A pervasive approach by implanted RFID tags
2011
Starting from the physical evidence that passive RFID systems may be used as self-sensing devices, the feasibility of human monitoring by means of implanted tags is here investigated. The key parameters to master with the purpose to enhance the sensitivity of the implanted radiosensor have been theoretically analyzed and numerically applied to a specific medical problem, i.e. the continuous monitoring of liver cancer evolution. Preliminary experimental results with simplified phantoms corroborate the analysis.
Passive UHF RFID antennas for sensing applications: Principles, methods, and classifcations
2013
UHF passive radio-frequency identification technology is rapidly evolving from simple labeling of things to wireless pervasive sensing. A remarkable number of scientific papers demonstrate that objects in principle can have their physical properties be remotely tracked and monitored all along their life cycle. The key background is a new paradigm of antenna design that merges together the conventional communication issues with more-specific requirements about sensitivity to time-varying boundary conditions. This paper presents a unified review of the state of the art of the tag-as-sensor problem. Particular care is taken to formalize the measurement indicators and the communication and sens…