Signaling Scheme Research Articles

Atypical cyclic di-AMP signaling is essential for Porphyromonas gingivalis growth and regulation of cell envelope homeostasis and virulence

Microbial pathogens employ signaling systems through cyclic (di-) nucleotide monophosphates serving as second messengers to increase fitness during pathogenesis. However, signaling schemes via second messengers in Porphyromonas gingivalis, a key Gram-negative anaerobic oral pathogen, remain unknown. Here, we report that among various ubiquitous second messengers, P. gingivalis strains predominantly synthesize bis-(3′,5′)-cyclic di-adenosine monophosphate (c-di-AMP), which is essential for their growth and survival. Our findings demonstrate an unusual regulation of c-di-AMP synthesis in P. gingivalis. P. gingivalis c-di-AMP phosphodiesterase (PDE) gene (pdepg) positively regulates c-di-AMP synthesis and impedes a decrease in c-di-AMP concentration despite encoding conserved amino acid motifs for phosphodiesterase activity. Instead, the predicted regulator gene cdaR, unrelated to the c-di-AMP PDE genes, serves as a potent negative regulator of c-di-AMP synthesis in this anaerobe. Further, our findings reveal that pdepg and cdaR are required to regulate the incorporation of ATP into c-di-AMP upon pyruvate utilization, leading to enhanced biofilm formation. We show that shifts in c-di-AMP signaling change the integrity and homeostasis of cell envelope, importantly, the structure and immunoreactivity of the lipopolysaccharide layer. Additionally, microbe–microbe interactions and the virulence potential of P. gingivalis were modulated by c-di-AMP. These studies provide the first glimpse into the scheme of second messenger signaling in P. gingivalis and perhaps other Bacteroidetes. Further, our findings indicate that c-di-AMP signaling promotes the fitness of the residents of the oral cavity and the development of a pathogenic community.

Eigendecomposition-Precoded Faster-Than-Nyquist Signaling With Index Modulation

In this paper, we propose a precoded faster-than-Nyquist (FTN) signaling technique for time-domain single-carrier index-modulated symbol transmission. More precisely, eigenvalue decomposition (EVD) precoding is adopted for the FTN transmission of data bits modulated by single-carrier time-domain index modulation (IM). While the FTN scheme increases the spectral efficiency and data rate by increasing the density of transmit symbols, the time-domain IM works towards the same objective while maintaining symbol sparsity. We analytically derive the constrained capacity of the proposed system. Our simulation results show that the proposed scheme has better bit error ratio (BER) performance than the conventional FTN-IM scheme, particularly for the scenario of a higher packing ratio. With the proposed scheme, a 2.5 dB performance gain is observed at the BER of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−4</sup> , where the packing ratio is 0.7 and the roll-off factor is 0.5 in the channel-uncoded scenario. We further analyze our scheme’s performance by characterizing its minimum Euclidean distance and inter-symbol interference. Furthermore, we present a three-stage serially concatenated iterative detection architecture for the proposed EVD-FTN-IM signaling scheme. It is demonstrated in our simulations that a near-capacity BER performance is achievable in the proposed turbo-coded FTN-IM scheme.

Algorithmic Bayesian Persuasion with Combinatorial Actions

Bayesian persuasion is a model for understanding strategic information revelation: an agent with an informational advantage, called a sender, strategically discloses information by sending signals to another agent, called a receiver. In algorithmic Bayesian persuasion, we are interested in efficiently designing the sender's signaling schemes that lead the receiver to take action in favor of the sender. This paper studies algorithmic Bayesian-persuasion settings where the receiver's feasible actions are specified by combinatorial constraints, e.g., matroids or paths in graphs. We first show that constant-factor approximation is NP-hard even in some special cases of matroids or paths. We then propose a polynomial-time algorithm for general matroids by assuming the number of states of nature to be a constant. We finally consider a relaxed notion of persuasiveness, called CCE-persuasiveness, and present a sufficient condition for polynomial-time approximability.

Stationary scattering solution and logic operations in X-coupled tight-binding chains

The realization of logical operations on X-shaped structures consisting of two discrete input chains, which are linearly connected to two output chains through a central coupling region, is investigated. We provide the exact stationary scattering solution for the harmonic waves propagating in the proposed structure and report the full transmission spectrum. We show that a number of Boolean logic operations can be implemented using a digitization scheme of the output signal based on the amplitude modulation of the transmission coefficients. In particular, we show that the relative phase between input harmonics can be used as a control parameter to select the desired logic operation. A detailed study of the contrast ratio is used to identify optimal regions in the parameter space for the operation of each logical function.

Comparative Transcriptomics of Gonads Reveals the Molecular Mechanisms Underlying Gonadal Development in Giant Freshwater Prawns (Macrobrachium rosenbergii)

The giant freshwater prawn, Macrobrachium rosenbergii, is a prawn that has economic significance throughout the world. It exhibits sex-related growth dimorphism, whereby the males grow significantly more rapidly than the females. Therefore, a study on the molecular regulatory mechanism, which underlies the sexual differentiation of M. rosenbergii, is of both scientific and commercial importance. However, a scarcity of genomic and transcriptomic resources severely limits our knowledge of the sexual differentiation mechanisms in M. rosenbergii. Here, transcriptome sequencing of several gonadic samples of males and females in M. rosenbergii was performed to investigate the molecular basis underlying gonadal development. Our results showed that 2149 unigenes presented as differentially expressed genes (DEGs) in the ovaries of females compared to the testes of males, which contained 484 down-regulated and 1665 up-regulated genes. Enrichment analysis of DEGs revealed many of these genes to be related to sexual differentiation and gonadal development. From our transcriptome analyses, and as confirmed by quantitative real-time PCR, male-related genes (Mrr, MRPINK, IR, IAGBP, TESK1, and dsx) in the testes were significantly up-regulated, and female-related genes (ERR, Sxl3, cyclinB, Dmrt99B, PPP2A, and ADCY9) in the ovaries were also significantly up-regulated. This indicates the potential role these genes play in the gonadal development of M. rosenbergii. Furthermore, multiple signal transduction pathways relating to gonadal maturation and spermatogenesis, including MAPK, were identified herein. Our data also supports previous ideas that IAG and IAGBP-IR signaling schemes could help in the regulation of testis’ development in M. rosenbergii and the ERR gene could regulate ovarian development by affecting the expression of cyclinB, PPP2A, and ADCY9. The data from this study provides incredibly usefully genomic resources for future research on the sexual differentiation and practical aquaculture of M. rosenbergii.

Ultrahigh-Net-Bitrate 363 Gbit/s PAM-8 and 279 Gbit/s Polybinary Optical Transmission Using Plasmonic Mach-Zehnder Modulator

We summarize our experimental exploration of the capabilities of an ultrabroad-bandwidth plasmonic Mach-Zehnder modulator (MZM), in an intensity modulation and direct detection (IM/DD) system for short-reach optical transmission up to 10 km. We study modulation, transmission, and reception of ultrahigh-symbol-rate (up to 304 GBd) multi-level optical signals with two different signaling schemes: pulse amplitude modulation (PAM), with up to 8 amplitude levels and partial-response-encoded binary (polybinary) modulation with memory length up to 4. By mapping the performance to a concatenated soft-decision (SD) and hard-decision (HD) forward error correction (FEC) coding scheme, a net bitrate of 363.4 Gbit/s is possible with PAM-8 signaling and 279.0 Gbit/s with tetrabinary (polybinary) signaling after 10 km standard single-mode fiber transmission. Considering an HD-only coding scheme, a net bitrate of 318.0 Gbit/s is possible with PAM-6 and 277.1 Gbit/s with tetrabinary.

Serial and parallel convolutional neural network schemes for NFDM signals

Two conceptual convolutional neural network (CNN) schemes are proposed, developed and analysed for directly decoding nonlinear frequency division multiplexing (NFDM) signals with hardware implementation taken into consideration. A serial network scheme with a small network size is designed for small user applications, and a parallel network scheme with high speed is designed for places such as data centres. The work aimed at showing the potential of using CNN for practical NFDM-based fibre optic communication. In the numerical demonstrations, the serial network only occupies 0.5 MB of memory space while the parallel network occupies 128 MB of memory but allows parallel computing. Both network schemes were trained with simulated data and reached more than 99.9% accuracy.

A True Full-Duplex IO (TFD-IO) With Background SI Cancellation for High-Density Interfaces

In this work, we have proposed and experimentally demonstrated a true full-duplex input–output (TFD-IO) for high-speed high-density interfaces. The proposed TFD-IO can be used as an independent module that converts a unidirectional IO/interconnect to a fully bidirectional IO/interconnect, to ideally double the throughput of the high-speed interface. The TFD-IO uses a correlation-based technique to cancel the self-interference (SI) and echoes adaptively in the background. The signals transmitted from the near-end and the far-end can use independent baud-rates and signaling schemes in a TFD-IO. A proof-of-concept design of the TFD-IO module has been fabricated in a 65-nm CMOS technology, and demonstrated with bidirectional throughputs of up to 12.8 Gb/s.

On evaluation of patrolling and signalling schemes to prevent poaching in green security games

• Green Security tackles the problem of illegal poaching, which includes scope of research in sensor signalling. • Radio signalling drone assistance yields performance boost over previously proposed sound and light signaling methods. • Energy saving strategy by not moving at full capacity does not degrade performance proportionally, indicating its benefit. • Conceptually partitioning the area-to-be-protected has shown benefit in certain patrolling scenarios. • The number of drones to be deployed has a saturation point, deploying more drones might not always increase performance. Illegal poaching poses threat to the natural ecosystem, hastens the extinction of animal species, and disrupts forestry and other natural resources. Countries usually deploy security personnel to protect these resources from poachers. However, preservation of such resources is oftentimes hindered by the lack of manpower of concerned agencies. Green security, a discipline that leverages the game theoretic concepts to assist human patrols has recently emerged to mitigate this problem. Over the past few years, a good number of studies have been conducted on various aspects of such security systems including poachers’ behavior modeling, optimal patrolling route generation, and signalling mechanisms to assist guards. In this paper, we contribute to the literature in the following three ways. First, we offer a radio signalling scheme to assist human guards. Second, we introduce two concepts regarding the guarding patterns: (a) the concept of “boundedness” is coined which limits the patrolling area of human guards and (b) the concept of “move skipping” is put forth which is to compulsorily abstain from moving at some timesteps while patrolling. Third, we investigate the required number of deployed drones to achieve an effective monitoring. Our simulation results show that the proposed schemes have the capability to reduce poaching occurrences, while, at the same time, decrease over-patrolling and fuel usage. Our research focuses on analyzing and comparing different variations of a green security game setup. In our research, we analyze and compare these different aspects of various patrolling patterns and based on our findings, we provide useful insights that contribute to the development of the research field of green security and security schemes in general, including both human patrols and drones, which are deployed to prevent poachers or adversaries from poaching resources.

An Adaptive and Greener Traffic Signal Coordination Scheme for Transport 4.0

Traffic congestion has become a major concern, aroused as a result of increased population and urbanization. Hence, novel and innovative methods for controlling ever-increasing traffic volumes are essential. Conventional traffic light schemes are the most popular method of controlling traffic, and it is logical and economical to make research endeavors to optimize their existing performance. Despite numerous studies, the aforementioned problem has not been optimally and sufficiently solved. In this research, we introduce an adaptive traffic signaling scheme based on vehicle density to facilitate optimal traffic signal control as well as effective traffic management. We also propose effective coordination of the traffic amongst the junctions. Here, the live video is utilized as an input provided to a deep Q network to provide adaptive phase timings as the output. In the proposed scheme, we introduced per car unit (PCU) as a novel parameter to represent the effect of each vehicle type on traffic conditions. Numerous filed trials on real-time data amply prove that the proposed scheme enhances the average speed of traffic up to 5.597 km/h. The proposed scheme shows an average increment of 175.71% in average mean speed compared to the existing static schemes. Except for the high traffic scenario, for both mid traffic and low traffic scenarios, the proposed scheme shows a considerable improvement in both average densities and maximum densities. In the mid-traffic scenario, the average speed shows an improvement of 3.85 km/h, while in the low traffic scenario, the average mean speed shows an improvement of 7.96 km/h. A reduction in fuel consumption and average delay were also observed, which will lead to a greener Transport 4.0.

A New High-Capacity Audio Watermarking Based on Wavelet Transform using the Golden Ratio and TLBO Algorithm

Digital watermarking is one of the best solutions for copyright infringement, copying, data verification, and illegal distribution of digital media. Recently, the protection of digital audio signals has received much attention as one of the fascinating topics for researchers and scholars. In this paper, we presented a new high-capacity, clear, and robust audio signaling scheme based on the DWT conversion synergy and golden ratio advantages using the TLBO algorithm. We used the TLBO algorithm to determine the effective frame length and embedded range, and the golden ratio to determine the appropriate embedded locations for each frame. First, the main audio signal was broken down into several sub-bands using a DWT in a specific frequency range. Since the human auditory system is not sensitive to changes in high-frequency bands, to increase the clarity and capacity of these sub-bands to embed bits we used the watermark signal. Moreover, to increase the resistance to common attacks, we framed the high-frequency bandwidth and then used the average of the frames as a key value. Our main idea was to embed an 8-bit signal simultaneously in the host signal. Experimental results showed that the proposed method is free from significant noticeable distortion (SNR about 29.68dB) and increases the resistance to common signal processing attacks such as high pass filter, echo, resampling, MPEG (MP3), etc.

Strategic signaling for utility control in audit games

As an effective method to protect the daily access to sensitive data against malicious attacks, the audit mechanism has been widely deployed in various practical fields. In order to examine security vulnerabilities and prevent the leakage of sensitive data in a timely manner, the database logging system usually employs an online signaling scheme to issue an alert when suspicious access is detected. Defenders can audit alerts to reduce potential damage. This interaction process between a defender and an attacker can be modeled as an audit game. In previous studies, it was found that sending real-time signals in the audit game to warn visitors can improve the benefits of the defender. However, the previous approaches usually assume perfect information of the attacker, or simply concentrate on the utility of the defender. In this paper, we introduce a brand-new zero-determinant (ZD) strategy to study the sequential audit game with online signaling, which empowers the defender to unilaterally control the utility of visitors when accessing sensitive data. In addition, an optimization scheme based on the ZD strategy is designed to effectively maximize the utility difference between the defender and the attacker. Extensive simulation results show that our proposed scheme enhances the security management and control capabilities of the defender to better handle different access requests and safeguard the system security in a cost-efficient manner.

Spectral crosstalk in photoacoustic computed tomography

Multispectral photoacoustic (PA) imaging faces two major challenges: the spectral coloring effect, which has been studied extensively as an optical inversion problem, and the spectral crosstalk, which is basically a result of non-ideal acoustic inversion. So far, there is no systematic work to analyze the spectral crosstalk because acoustic inversion and spectroscopic measurement are always treated as decoupled. In this work, we theorize and demonstrate through a series of simulations and experiments how imperfect acoustic inversion induces inaccurate PA spectrum measurement. We provide detailed analysis to elucidate how different factors, including limited bandwidth, limited view, light attenuation, out-of-plane signal, and image reconstruction schemes, conspire to render the measured PA spectrum inaccurate. We found that the model-based reconstruction outperforms universal back-projection in suppressing the spectral crosstalk in some cases.

Optimisation of Signal Timing at Intersections with Waiting Areas

Unconventional geometric designs such as continu-ous-flow intersections, U-turns, and contraflow left-turn lanes have been proposed to reduce left-turn conflicts and improve intersection efficiency. Having a waiting area at a signalised intersection is an unconventional de-sign that is used widely in China and Japan to improve traffic capacity. Many studies have shown that waiting areas improve traffic capacity greatly, but few have con-sidered how to improve the benefits of this design from the aspect of signal optimisation. Comparing the start-up process of intersections with and without waiting areas, this work explores how this geometric design influenc-es vehicle transit time, proposes two signal optimisation strategies, and establishes a unified capacity calculation model. Taking capacity maximisation as the optimisation function, a cycle optimisation model is derived for over-saturated intersections. Finally, the relationship among waiting-area storage capacity, cycle time, and traffic ca-pacity is discussed using field survey data. The results of two cases show that optimising the signal scheme helps reduce intersection delays by 10–15%.

An effective GDI (Gate Diffusion Input) Based 16- bit Shift Register Design for Power and Area Optimization

Abstract: Sequential circuit design is heavily influenced by power consumption and area reduction. Mainly consisted is shown here. Rather than using flip flops, pulsed latches are used to limit the amount of space these utilize. The shift register uses a minimal number of pulsed clock signals by combining the latches into numerous sub shifter registers and using Multiplexer and additional temporary storage latches. Multiple non-overlap delayed pulsed clock signal schemes are presented for data synchronization in a multi bit shift register to decrease power consumption. In order to maintain the current system, Tanner SEDIT will be used with Taiwan Semiconductor (TSMC) 0.18mm technology. Designing low-power digital combinational circuits using Gate Diffusion Input(GDI) is a common practice nowadays. When used in particular operating conditions, the GDI approach restores the in-cell swing by implementing sophisticated logic functions on two transistors. This method reduces power consumption, propagation latency, and digital circuit size while maintaining low complexity of logic design. Dual Edge Triggered Flip Flop(DETFF) implementation using GDI technology is introduced as an improvement to the shift register design. This idea also takes into account time restrictions, which can be reduced with the least amount of management. Keywords: Shift Register, Thermometer Code, Gate Diffusion Input, Dual Edge Triggered Flip-Flop, Propagation latency.

Cooperative Terrestrial-Underwater Wireless Optical Links by Using an Amplify-and-Forward Strategy.

In this paper, we analyze a combined terrestrial-underwater optical communication link for providing high-speed optical connectivity between onshore and submerge systems. For this purpose, different transmission signaling schemes were employed to obtain performance results in terms of average bit error rate (ABER). In this sense, from the starting point of a known conditional bit-error-rate (CBER) in the absence of turbulence, the behavior of the entire system is obtained by applying an amplify-and-forward (AF) based dual-hop system: The first link is a terrestrial free-space optical (FSO) system assuming a Málaga distributed turbulence and, the second one, is an underwater FSO system with a Weibull channel model. To obtain performance results, a semi-analytical simulation procedure is applied, using a hyper-exponential fitting technique previously proposed by the authors and leading to BER closed-form expressions and high-accuracy numerical results.

Eigendecomposition-Precoded Faster-Than-Nyquist Signaling With Optimal Power Allocation in Frequency-Selective Fading Channels

In this paper, we propose eigenvalue decomposition (EVD)-precoded faster-than-Nyquist (FTN) signaling with power allocation in a frequency-selective fading channel. More specifically, we derive the mutual information associated with the proposed FTN signaling. Then, the optimal power coefficients are calculated such that the derived mutual information is maximized. Our analytical performance results show that the proposed FTN signaling scheme achieves a higher information rate than the conventional FTN signaling scheme without relying on power allocation and the classic Nyquist signaling scheme, under the assumption that all the schemes employ a root-raised cosine shaping filter. Moreover, we derive the proposed scheme&#x2019;s achievable information rate in the presence of channel estimation errors. Furthermore, our numerical simulation results for the bit error ratio performance and the power spectral density demonstrate that the proposed FTN scheme outperforms the conventional Nyquist signaling scheme without incurring any bandwidth broadening.

Covert Wireless Communication With Noise Uncertainty in Space-Air-Ground Integrated Vehicular Networks

In this paper, we propose a covert wireless uplink transmission strategy in space-air-ground integrated vehicular networks, where the source vehicle transmits its own message over the channel that being used by the host communication system, to avoid being detected by the warden. It is obvious that the data transmission efficiency of the covert communication system is limited due to the co-channel interference. To improve the data transmission efficiency, we consider that the covert communication system adopts improper Gaussian signaling (IGS). We formulate a joint transmit power and IGS factor optimization problem to minimize the outage probability of the covert communication system. The minimum error detection probability of the warden is first analyzed with noise uncertainty, which is used to measure the system covertness. Under the constraints of the quality of service (QoS) of host communication system and the covertness requirement, the optimal transmit power is first derived with proper Gaussian signaling (PGS) scheme. Then, with the approximate outage probability derived under IGS scheme, the optimization problem is solved by jointly designing the transmit power and IGS factor. Finally, we provide extensive numerical results to validate the proposed covert transmission strategy, and demonstrate that the IGS scheme is beneficial in improving the data transmission efficiency in terms of outage probability compared to PGS scheme.

Asymmetric Crosstalk Harnessed Signaling for Large 3D Routing Integration

This paper presents a high level of integration for parallel source-synchronous interfaces using Asymmetric Crosstalk Harnessed Signaling (ACHS) on 3D routing environments. ACHS is shown to successfully overcome the high noise susceptibility related to the common encoding eigenmode present in the original Crosstalk Harnessed Signaling (CHS) scheme, with a small routing overhead. In this study, a bus design case is presented where multiple channels are wired together in a 3D routing environment by a multi-stripline stackup. CHS and ACHS performances are compared using the same routing realestate availability; ACHS shows a far superior performance due to the absence of the common encoding mode. The best performing eigenmodes are applied to the strobe encoding to achieve very good integrity for this critical signal.

Pulse-Shaped Walsh–Hadamard Orthogonal Signaling for Multiuser DS-UWB Systems

This article presents signaling schemes for direct-sequence ultrawideband (DS-UWB) multiuser communication with pulse shaping and orthogonal Walsh–Hadamard (WH) modulation. A waveform design approach is applied to obtain novel UWB pulses with strict spectral emission compliance and improved multiaccess capability. WH codeword sequences are then combined with optimally shaped DS-UWB signals, yielding orthogonal modulation formats that can be scaled to variable order while retaining the desired spectral characteristics and achieving robust performance in multiuser, multipath-impaired environments. Interference analysis with a random spreading model is used to derive decision statistics with MRC over frequency-selective Nakagami fading channels, and analytical expressions are obtained for outage and bit error probabilities. Comparative numerical results and sensitivity analysis with respect to waveform selection, modulation order, and channel parameters are given to demonstrate the merits of the proposed orthogonal WH-based DS-UWB schemes in terms of improved outage and error performance, and increased multiuser capacity.