We analyze how the performance of a quantum-repeater network depends on the protocol employed to distribute entanglement, and we find that the choice of repeater-to-repeater link protocol has a ...profound impact on entanglement-distribution rate as a function of hardware parameters. We develop numerical simulations of quantum networks using different protocols, where the repeater hardware is modeled in terms of key performance parameters, such as photon generation rate and collection efficiency. These parameters are motivated by recent experimental demonstrations in quantum dots, trapped ions, and nitrogen-vacancy centers in diamond. We find that a quantum-dot repeater with the newest protocol ('MidpointSource') delivers the highest entanglement-distribution rate for typical cases where there is low probability of establishing entanglement per transmission, and in some cases the rate is orders of magnitude higher than other schemes. Our simulation tools can be used to evaluate communication protocols as part of designing a large-scale quantum network.
The optimal design of repeaters for current-mode (CM) nano-interconnects is conducted and compared with that for voltage-mode (VM) ones. Both Cu and carbon nanotube (CNT) nano-interconnects are ...considered and studied, with the contact resistance treated appropriately. In comparison with the VM ones, the CM nano-interconnects can not only demonstrate better electrical performance, but also require fewer repeaters, thereby saving more valuable chip area. In the delay-optimal repeater design of multi-walled CNT interconnects, for instance, the optimal number of repeaters can be reduced by 120% with the implementation of CM signalling scheme.
A photonics-based radar jamming signal generator is proposed in this paper. By adjusting a polarization controller, interrupted-sampling repeater jamming (ISRJ), comb spectrum modulation jamming ...(CSMJ), ISRJ and CSMJ composite jamming can be respectively generated after photoelectric conversion. We have experimentally verified the generation of ISRJ signals with duty cycles of 50% and 25%, the generation of CSMJ signals with comb spectrum frequency intervals of 5 MHz and 10 MHz, and the generation of their composite jamming signals in the Ku band. Additionally, the ISRJ and CSMJ composite jamming effect of radar signals in the Ka band has been tested. After matched filtering processing, multiple false targets are produced and the total number of jamming targets can be up to 25, demonstrating significant jamming effects. The proposed structure can generate multi-format jamming signals without using digital radio frequency memory, which is suitable for producing high-frequency and large-bandwidth jamming signals. It can be applied in electronic countermeasure systems.
•The scheme can generate multi-format jamming signals for LFM signal, namely interrupted-sampling repeater jamming (ISRJ), comb spectrum modulation jamming (CSMJ), ISRJ and CSMJ composite jamming.•The scheme does not use digital radio frequency memory, which is easy to generate high frequency and large bandwidth jamming signals. The experimental results show that the LFM signal with 1-GHz bandwidth in Ku band and the LFM signal with 1.2-GHz bandwidth in Ka band have good jamming effects.•After matched filtering processing, multiple false targets are generated and the total number of jamming targets can be up to 25, demonstrating significant jamming effects. The scheme has good application value in electronic countermeasure system.
Abstract
This paper investigates the sortal classifier system in Zauzou, a Tibeto-Burman language spoken in Southwest
China. Three etymological subclasses – repeater, non-repeater, and ...quasi-repeaters – are identified in two morphosyntactic
contexts: the bare classifier phrase
n+clf
and the full noun phrase
n+mod+clf
, serving as an
“individualizer” that transforms unindividualized nominal concepts into referential individuals. The three types of classifiers
classify nouns on the basis of different semantic parameters that differ in terms of semantic contrastiveness. Animacy, shape,
size, rigidity and quanta are non-contrastive semantic parameters commonly found among non-repeaters. Repeaters and
quasi-repeaters categorize nouns primarily on the basis of semantically contrastive taxonomy, meronomy, or arrangement. With
respect to the function of quantification, repeaters, quasi-repeaters, and non-repeaters are identical in
n+mod+clf
but
diverge in
n+clf
. They do not uniformly render the singular interpretation with all kinds of referents in
n+clf
. Non-repeaters are more grammaticalized classifiers than (quasi-)repeaters. The Zauzou data provide evidence
for the development from repeaters to non-repeaters, on a par with the commonly recognized grammaticalization path from nouns to
classifiers, which is conditioned by two types of “parameter shift”. This study offers a descriptive model that effectively
captures the relationship between semantic-functional properties of sortal classifiers and their historical development in
“repeater” languages.
Interrupted Sampling Repeater Jamming (ISRJ) falls within the category of intrapulse coherent deception interference. ISRJ employs the principle of undersampling to engender multiple spurious target ...peaks on the range profile, thereby disrupting the detection and tracking of genuine targets. To address this challenge, this study introduces a novel method grounded in the waveform domain to mitigate ISRJ before matched filtering. First, considering the partial matching attributes of ISRJ, an expanded domain, specifically the waveform domain, is incorporated into the matched filtering. This augmentation enables the investigation of local features within the interference signals and components of authentic target echo signals. Moreover, adaptive threshold functions are defined for each waveform domain. Subsequently, the introduction of the Kalman filter enables the state estimation of waveform domain signals. Additionally, valid and invalid integral elements are discriminated within the waveform domain signals via adaptive threshold detection, and a state space estimation is formulated, specifically concerning the valid integral elements. In conclusion, by suppressing the invalid integral elements within the waveform domain signals, the proposed approach simultaneously supplements the estimated state space of valid integral elements with their corresponding length components. This preservation of residual valid integral elements, coupled with integration operation, yields a range profile outcome devoid of deceptive interference artifacts. Importantly, the approach proposed herein operates independently of any prior information regarding the interference device parameters, thereby substantially reducing the effect of ISRJ. Simulation experiments illustrate that, in comparison with traditional methodologies, the method proposed in this study exhibits remarkably superior resistance against the ISRJ interference challenges.
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The topography of the Tibetan Plateau (TP) has shaped the paleoclimatic evolution of the Asian monsoon. However, the influence of the TP on the global climate, beyond the domain of ...the Asian monsoon, remains unclear. Here we show that the Pacific and Atlantic Oceans act as efficient repeaters that boost the global climatic impact of the TP. The simulations demonstrate that oceanic repeaters enable TP heating to induce a wide-ranging climate response across the globe. A 1 °C TP warming can result in a 0.73 °C temperature increase over North America. Oceanic repeaters exert their influence by enhancing the air-sea interaction-mediated horizontal heat and moisture transport, as well as relevant atmospheric circulation pathways including westerlies, stationary waves, and zonal-vertical cells. Air-sea interactions were further tied to local feedbacks, mainly the decreased air-sea latent heat flux from the weakening air-sea humidity difference and the increased shortwave radiation from sinking motion-induced cloud reduction over the North Pacific and Atlantic Oceans. Our findings highlight the crucial influence of TP heating variation on the current climate under a quasi-fixed topography, in contrast to topography change previously studied in paleoclimate evolution. Therefore, TP heating should be considered in research on global climate change.
Increasing incidents of cyber attacks and evolution of quantum computing poses challenges to secure existing information and communication technologies infrastructure. In recent years, quantum key ...distribution (QKD) is being extensively researched, and is widely accepted as a promising technology to realize secure networks. Optical fiber networks carry a huge amount of information, and are widely deployed around the world in the backbone terrestrial, submarine, metro, and access networks. Thus, instead of using separate dark fibers for quantum communication, integration of QKD with the existing classical optical networks has been proposed as a cost-efficient solution, however, this integration introduces new research challenges. In this paper, we do a comprehensive survey of the state-of-the-art QKD secured optical networks, which is going to shape communication networks in the coming decades. We elucidate the methods and protocols used in QKD secured optical networks, and describe the process of key establishment. Various methods proposed in the literature to address the networking challenges in QKD secured optical networks, specifically, routing, wavelength and time-slot allocation (RWTA), resiliency, trusted repeater node (TRN) placement, QKD for multicast service, and quantum key recycling are described and compared in detail. This survey begins with the introduction to QKD and its advantages over conventional encryption methods. Thereafter, an overview of QKD is given including quantum bits, basic QKD system, QKD schemes and protocol families along with the detailed description of QKD process based on the Bennett and Brassard-84 (BB84) protocol as it is the most widely used QKD protocol in the literature. QKD system are also prone to some specific types of attacks, hence, we describe the types of quantum hacking attacks on the QKD system along with the methods used to prevent them. Subsequently, the process of point-to-point mechanism of QKD over an optical fiber link is described in detail using the BB84 protocol. Different architectures of QKD secured optical networks are described next. Finally, major findings from this comprehensive survey are summarized with highlighting open issues and challenges in QKD secured optical networks.
•The cross ambiguity function of ISRJ is derived to demonstrate jamming distribution characteristics visually.•An ISRJ recognition and suppression method based on phase-coded signal processing is ...proposed.•The proposed method does not need to estimate ISRJ parameters, and it is applicable for suppressing direct forwarding ISRJ, repeated forwarding ISRJ, and frequency shifting ISRJ.
In modern electronic warfare, interrupted sampling repeater jamming (ISRJ) seriously affects radar target detection performance. It has the advantages of flexible modulation and fast response. The existing approaches mostly require accurate ISRJ parameter estimation and only apply to a specific type of ISRJ. We propose an ISRJ recognition and suppression method based on phase-coded signal processing. By analyzing the cross ambiguity function (CAF) of ISRJ, we find that ISRJ can form multiple peaks, and these peaks are uniformly distributed on the Doppler cut of the CAF. Using this characteristic, we propose an ISRJ recognition method based on Doppler compensation processing. On this basis, a Doppler filtering processing method is proposed to suppress the ISRJ. Both simulated and measured results corroborate the effectiveness of the ISRJ suppression with the developed methods.
•The distribution of entangled state to far distances is of enough importance in quantum technologies and quantum information processing.•Doing this task with trapped atomic ions using quantum ...repeater protocol is the purpose of this paper.•Entanglement swapping techniques in optomechanical cavities and Bell state measurement have been used to do the task.•Therefore using trapped atomic ions in optomechanical cavities is the novelty of this work.•The effects of detuning and amplitude of pump laser on the entanglement and success probability are considered.
Distribution of the entangled state of trapped atomic ions to long distance using quantum repeater protocol is considered. Indeed, the long distance is divided into short parts, and then using entanglement generation and entanglement swapping techniques in optomechanical cavities, the entanglement is distributed. To do the task, we perform interaction between trapped atomic ions in optomechanical cavities, operate proper measurements on trapped ions and also make Bell state measurement as a well-known way to swap the entanglement. Accordingly, the entanglement is distributed between target ions with satisfactory values of success probability and entanglement degree. The effects of detuning and amplitude of pump laser on the entanglement and success probability are evaluated. The fluctuations of entanglement and success probability are decreased by increasing of detuning. Via increasing the amplitude of pump laser, the maxima of entanglement are repeated more times and success probability undergoes the collapse-revival phenomenon.
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