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作者： Bárta, Tomáš Charles University of Prague

According to the classical efficient-coding hypothesis, biological neurons are naturally adapted to transmit and process information about the stimulus in an optimal way. Shannons information theory provides methods to compute the fundamental limits on maximal information transfer by a general system. Understanding how these limits differ between different classes of neurons may help us to better understand how sensory and other information is processed in the brain. In this work we provide a brief review of information theory and its use in computational neuroscience. We use mathematical models of neuronal cells with stochastic input that realistically reproduce different activity patterns observed in real cortical neurons. By employing the neuronal input-output pro- perties we calculate several key information-theoretic characteristics, including the information capacity. In order to determine the information capacity we propose an iterative extension of the Blahut-Arimoto algorithm that generalizes to continuous input channels subjected to constraints. Finally, we compare the information optimality conditions among different models and parameter sets. 1

关键词： information capacity neuronal model frequency coding

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Analog Signaling With the "Digital" Molecular Switch CaMKII

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FRONTIERS IN COMPUTATIONAL NEUROSCIENCE 2018年 12卷 92页

作者： Clarke, Stephen E. Stanford Univ Dept Neurosurg Dept Bioengn Stanford CA 94305 USA

Molecular switches, such as the protein kinase CaMKII, play a fundamental role in cell signaling by decoding inputs into either high or low states of activity;because the high activation state can be turned on and persist after the input ceases, these switches have earned a reputation as "digital." Although this on/off, binary perspective has been valuable for understanding long timescale synaptic plasticity, accumulating experimental evidence suggests that the CaMKII switch can also control plasticity on short timescales. To investigate this idea further, a non-autonomous, nonlinear ordinary differential equation, representative of a general bistable molecular switch, is analyzed. The results suggest that switch activity in regions surrounding either the high- or low-stable states of activation could act as a reliable analog signal, whose short timescale fluctuations relative to equilibrium track instantaneous input frequency. The model makes intriguing predictions and is validated against previous work demonstrating its suitability as a minimal representation of switch dynamics;in combination with existing experimental evidence, the theory suggests a multiplexed encoding of instantaneous frequency information over short timescales, with integration of total activity over longer timescales.

关键词： molecular switches frequency coding stochastic resonance cellular computation CaMKII synaptic plasticity burst detection hill function

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Design and Analysis of C Shaped Chipless RFID Tag

Design and Analysis of C Shaped Chipless RFID Tag

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International Symposium on Wireless Systems and Networks (ISWSN)

作者： Mumtaz, Maleeha Amber, Syeda Fatima Ejaz, Asma Habib, Ayesha Jafri, Syeda Irum Amin, Yasar Univ Engn & Technol Dept Telecommun Engn Taxila Pakistan

ISBN: (纸本)9781538615560

In this paper, we demonstrate the passive chipless RFID tag having C shaped copper resonators operating in ultra wide band (2.5-5.5 GHz). The efficient bandwidth utilization is performed by using the frequency coding technique. The number of possible unique combinations is 2(10). Measurements and calculations are performed in frequency domain and the results are shown with the help of radar cross section (RCS) plot. The tag design is optimized and analyzed for three different substrates having same compact geometry of 20 x 40 mm(2). The comparative analysis shows that the overall bandwidth of FR4, Rogers RT5880 and Taconic TLX-0 is 2.85 GHz, 2.5 GHz and 2.03 GHz respectively. The proposed tag is a suitable candidate for applications requiring high data capacity with an average tag size and simple resonating structures.

关键词： bandwidth utilization chipless RFID frequency coding radar cross section

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frequency CODED QUANTUM KEY DISTRIBUTION CHANNEL BASED ON PHOTON AMPLITUDE-PHASE MODULATION

FREQUENCY CODED QUANTUM KEY DISTRIBUTION CHANNEL BASED ON PH...

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Conference on Systems of Signal Synchronization, Generating and Processing in Telecommunications (SINKHROINFO)

作者： Gabdulhakov, Ildaris M. Morozov, Oleg G. PJSC Tattelecom 57 N Ershov St Kazan 420061 Russia Kazan Natl Res Tech Univ 10 K Marx St Kazan 420111 Russia

ISBN: (纸本)9781538617861

The technology of frequency coding in channels of quantum key distribution allows to determine the ground state of photons through the value of the amplitude of its carrier, frequency modulated in phase (PM) or amplitude (AM) by a radio-frequency signal, and the resulting side components. Over the past twenty years, it has been substantially modified and improved. At the same time, in recent works, an expanded understanding of the frequency coding principle is used, in which each photon state is associated not with the phase of the modulating signal at a certain frequency, but with one or more sideband frequencies or the carrier frequency of the photon itself. The known schemes of electro-optical modulation and remodulation are described by the symmetric pairs PM-PM, AM-AM and AM-PM (PM-AM), where the first component determines the modulator type on the Alice side (legal subscriber - transmitter), and the second one on the side of Bob legal subscriber - receiver). It is noted, that the smallest value of QBER is achieved in schemes with a passive definition of one or two basic states of a photon, i.e. without the use of remodulation processes. The formation of a filter system is carried out using fiber Bragg gratings (FBG) or arrayed waveguide gratings (AWG), tuned to the photon carrier or it sideband components. In this paper, we present the results of constructing a universal system of quantum key distribution (QKD) based on the electro-optical AMPM-PMAM scheme, which makes it possible to realize all the above-mentioned schemes and additionally combined version. At the heart of the AMPM-PMAM system of the QKD system is the modulation transformation of the photon carrier based on the Il'inMorozov's method and its one-and two-modulator realizations. For the mathematical description of the scheme, the principles of constructing a single-port modulation microwave photonic link of a sequential type and photon modeling of electro-optical modulators were used. The use of

关键词： quantum cryptography quantum key distribution frequency coding electro-optical photon modulation amplitude-phase tandem modulation

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Changes in vocal parameters with social context in humpback whales: considering the effect of bystanders

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BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY 2016年第6期70卷 857-870页

作者： Dunlop, Rebecca A. Univ Queensland Sch Vet Sci Cetacean Ecol & Acoust Lab Gatton Qld 4343 Australia

Many theories and communication models developed from terrestrial studies focus on a simple dyadic exchange between a sender and receiver. During social interactions, the "frequency code" hypothesis suggests that frequency characteristics of vocal signals can simultaneously encode for static signaler attributes (size or sex) and dynamic information, such as motivation or emotional state. However, the additional presence of a bystander may result in a change of signaling behavior if the costs and benefits associated with the presence of this bystander are different from that of a simple dyad. In this study, two common humpback whale social calls ("wops" and "grumbles") were tested for differences related to group social behavior and the presence of bystanders. "Wop" parameters were stable with group social behavior, but were emitted at lower (14 dB) levels in the presence of a nearby singing whale compared to when a singing whale was not in the area. "Grumbles" were emitted at lower (30-39 Hz) fundamental frequencies in affiliative compared to non-affiliative groups and, in the presence of a nearby singing whale, were also emitted at lower (14 dB) levels. Vocal rates did not significantly change. The results suggest that, in humpbacks, the frequency in certain sound types relates to the social behavior of the vocalizing group, implying a frequency code system. The presence of a nearby audible bystander (a singing whale) had no effect on this frequency code, but by reducing their acoustic level, the signal-to-noise ratio at the singer would have been below 0, making it difficult for the singer to audibly detect the group. The frequency, duration, and amplitude parameters of humpback whale social vocalizations were tested between different social contexts: group social behavior (affiliating versus non-affiliating), the presence of a nearby singing whale, and the presence of a nearby non-singing group. "Grumbles" (commonly heard low-frequency unmodulated sounds) frequen

关键词： frequency coding Source level Social group Signal design Vocal communication

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frequency-coded quantum key distribution using amplitude-phase modulation 14

Frequency-coded quantum key distribution using amplitude-pha...

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14th International Conference on Optical Technologies for Telecommunications

作者： Morozov, Oleg G. Gabdulkhakov, Il'daris M. Morozov, Gennady A. Zagrieva, Aida R. Sarvarova, Lutsia M. Kazan Natl Res Tech Univ Dept Radiophoton & Microwave Tech R&D Inst Appl Electrodynam Photon & Living Syst 10 K Marx St Kazan 420111 RT Russia PJSC Tattelecom 57 N Ershova St Kazan 420061 RT Russia

ISBN: (纸本)9781510600485

Design principals of universal microwave photonics system for quantum key distribution with frequency coding are concerned. Its concept is based on the possibility of creating the multi-functional units to implement the most commonly used technologies of frequency coding: amplitude, phase and combined amplitude-phase modulation and re-modulation of optical carrier. The characteristics of advanced systems based on classical approaches and prospects of their development using a combination of amplitude modulation and phase commutation are discussed. These are the valuations how to build advanced systems with frequency coding quantum key distribution, including at their symmetric and asymmetric constructions, using of the mechanisms of the photon polarization states passive detection, based on the filters for wavelength division multiplexing of modulated optical carrier side components.

关键词： quantum cryptography quantum key distribution system frequency coding microwave photonics amplitude modulation phase modulation combined amplitude and phase modulation combined amplitude modulation and phase commutation

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A Solution to Harmonic frequency Problem: frequency and Phase coding-Based Brain-computer Interface

A Solution to Harmonic Frequency Problem: Frequency and Phas...

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International Joint Conference on Neural Networks (IJCNN)

作者： Wong, Chi Man Wang, Boyu Wan, Feng Mak, Peng Un Mak, Pui In Vai, Mang I. Univ Macau Dept Elect & Elect Engn Fac Sci & Technol Taipa Peoples R China

ISBN: (纸本)9781424496365

In this paper, we propose a modified visual stimulus generation method and feature detection algorithm to design a frequency and phase coding steady-state visual evoked potential (SSVEP) based brain-computer interface (BCI). By utilizing both frequency and phase information, we solve the harmonic frequency problem in our proposed SSVEP-BCI system. The offline experimental results show that the proposed feature detection algorithm can enhance the classification rate over 10% (from 69%+/- 12% to 82%+/- 8%) even though only one signal electrode is used and the harmonic frequencies (6367Hz, 13.33Hz, 8357Hz and 17.14Hz) are employed.

关键词： Joints Neural networks USA Councils brain-computer interfaces coding-based brain-computer interface encoding feature detection algorithm frequency 13.33 Hz frequency 17.14 Hz frequency 6.67 Hz frequency 8.57 Hz frequency coding harmonic frequency problem medical signal processing phase coding signal classification signal classification rate signal electrode steady-state visual evoked potential visual evoked potentials visual stimulus generation method

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fMRI of the Central Auditory System

fMRI of the Central Auditory System

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作者： Deborah Ann Hall Aspasia Eleni Paltoglou

Over the years, blood oxygen level-dependent (BOLD) fMRI has made important contributions to the understanding of central auditory processing in humans. Although there are significant technical challenges to overcome in the case of auditory fMRI, the unique methodological advantage of fMRI as an indicator of population neural activity lies in its spatial precision. It can be used to examine the neural basis of auditory representation at a number of spatial scales, from the micro-anatomical scale of population assemblies to the macro-anatomical scale of cortico-cortical circuits. The spatial resolution of fMRI is maximized in the case of mapping individual brain activity, and here it has been possible to demonstrate known organizational features of the auditory system that have hitherto been possible only using invasive electrophysiological recording methods. frequency coding in the primary auditory cortex is one such example that we shall discuss in this chapter. Of course, noninvasive procedures for neuroscience are the ultimate aim and as the field moves towards this goal by recording in awake, behaving animals so human neuroimaging techniques will be increasingly relied upon to provide an interpretive link between animal neurophysiology at the multi-unit level and the operation of larger neuronal assemblies, as well as the mechanisms of auditory perception itself. For example, the neural effects of intentional behavior on stimulus-driven coding have been explored both in animals, using electrophysiological techniques, and in humans, using fMRI. While the feature-specific effects of selective attention are well established in the visual cortex, the effect of auditory attention in the auditory cortex has generally been examined at a very coarse spatial scale. Ongoing research in our laboratory has started to address this question and here we present preliminary evidence for frequency-specific effects of attentional enhancement in the human auditory cortex. We end w

关键词： fMRI Neuroimaging Selective attention Technical challenges frequency coding Perceptual representation Task specificity

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3D Sonar System based on Mills Cross Antenna Configuration

3D Sonar System based on Mills Cross Antenna Configuration

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Oceans Conference

作者： Degel, C. Fonfara, H. Welsch, H. J. Becker, F. J. Hewener, H. Fournelle, M. Tretbar, S. H. Fraunhofer Inst Biomed Engn Div Ultrasound Ensheimer Str 48 D-66386 St Ingbert Germany

ISBN: (纸本)9781479949182

A special aperture for a 3D sonar system is the so called Mills Cross antenna configuration. The Mills Cross arrangement looks like a "T" in which both antennas have a special function. In our work one antenna, consisting of 128 piezoelectric transducer elements, is used to transmit sound into a volume of interest. The second one, also made of 128 piezoelectric transducers, is used for receiving the reflections from objects or surfaces in the vicinity of the antennas. Each transducer element has a convex curvature to cover at least 30 degrees of the elevational direction. With that a volume defined by sector angles of 30 degrees x 30 degrees can be measured. To achieve fast volumetric imaging a frequency coding is used to transmit signals in different directions at the same time. The received signals are decoded to determine the different signals coming from the different directions. In this work we present the basic working principals of the system and the first measurement results.

关键词： antenna arrays array signal processing piezoelectric transducers sonar signal processing 3D sonar system Mills Cross antenna configuration convex curvature frequency coding mills cross antenna configuration volumetric imaging Acoustic measurements Antenna measurements Antennas Sea measurements Sonar measurements Transducers

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FS4 for partial deafness treatment

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Cochlear implants international 2014年 15 Suppl 1卷 S78-80页

作者： Artur Lorens Małgorzata Zgoda Marek Polak Henryk Skarzynski

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