A new method for improving the inductively coupled data transmission rate of mooring buoy based on carrier signal frequency selection

In the inductively coupled data transmission system of the mooring buoy, the carrier signal frequency of the transmission channel is limited due to the inherent characteristics of the system, resulting in limited channel bandwidth. The limited channel bandwidth limits the increase in inductively coupled data transmission rate.In order to improve the inductively coupled data transmission rate of mooring buoy as much as possible without damaging the data transmission performance, a new method was proposed in this paper. The method is proposed to improve the data transmission rate by selecting the appropriate carrier signal frequencies based on the principle of maximizing the amplitude value of amplitude-frequency characteristic curve of the system. Research has been done according to this method as follows. Firstly, according to the inductively coupled transmission mooring buoy structure, the inductively coupled data transmission circuit model was established. The binary frequency shift keying(2FSK) digital signal modulation mode was selected. Through theoretical analysis, the relation between the carrier signal frequency and the data transmission performance, the relation between the carrier signal frequency and the 2FSK signal bandwidth were obtained. Secondly, the performance and the bandwidth of the signal transmission were studied for the inherent characteristics of the actual inductively coupled data transmission system. The amplitude-frequency characteristic of the system was analyzed by experiments. By selecting the appropriate carrier signal frequency parameters, an excellent data transmission performance was guaranteed and a large 2FSK signal bandwidth was obtained. Finally, an inductively coupled data transmission rate optimization experiment and a bit error rate analysis experiment were designed and carried out. The results show that the high-speed and reliable data transmission of the system was realized and the rate can reach 100 kbps.

Analysis of SIRVI model with time dependent coefficients and the effect of vaccination on the transmission rate and COVID-19 epidemic waves

COVID-19 epidemic models with constant transmission rate cannot capture the patterns of the infection data in the presence of pharmaceutical and non-pharmaceutical interventions during a pandemic.Because of this,a new modification of SIR model that contain the vaccination compartment with time dependent coefficients and weak/lossimmunity is explored.Literature review confirms that the effect of vaccination on the time dependent transmission rate is still an open problem.This study answers this open problem.In this study,we first prove the well-posedness and investigate the model dynamics to show their continuous dependence on the model parameters.We then provide an algorithm to derive the time-dependent transmission function for the epidemiologic model and the data of the infected cases.The derived coupled nonlinear differential equations show the effect of vaccination on the transmission rate.Unlike previous studies,we first filter the published data and solve the nonlinear coupled differential equations using the finite difference technique,where the coefficient of the coupled nonlinear differential equations is a function of given data.We then show that time-dependent transmission function can be represented by linear combinations of Gaussian radial base function.We then validate the prediction of our models using numerical simulations,where we used the published data of COVID-19 confirmed cases by the Ministries of Health in Saudi Arabia and Poland.Finally,the numerical solutions of a SIRVI model with time dependent transmission rate show that the waves for currently active cases are in good agreement with the data of Saudi Arabia and Poland.

Forecasting of COVID-19: spread with dynamic transmission rate

The COVID-19 was firstly reported in Wuhan,Hubei province,and it was brought to all over China by people travelling for Chinese New Year.The pandemic coronavirus with its catastrophic effects is now a global concern.Forecasting of COVID-19 spread has attracted a great attention for public health emergency.However,few re-searchers look into the relationship between dynamic transmission rate and preventable measures by authorities.In this paper,the SEIR(Susceptible Exposed Infectious Recovered)model is employed to investigate the spread of COVID-19.The epidemic spread is divided into two stages:before and after intervention.Before intervention,the transmission rate is assumed to be a constant since individual,community and government response has not taken into place.After intervention,the transmission rate is reduced dramatically due to the societal actions or measures to reduce and prevent the spread of disease.The transmission rate is assumed to follow an exponential function,and the removal rate is assumed to follow a power exponent function.The removal rate is increased with the evolution of the time.Using the real data,the model and parameters are optimized.The transmission rate without measure is calculated to be 0.033 and 0.030 for Hubei and outside Hubei province,respectively.After the model is established,the spread of COVID-19 in Hubei province,France and USA is predicted.From results,USA performs the worst according to the dynamic ratio.The model has provided a mathematical method to evaluate the effectiveness of the government response and can be used to forecast the spread of COVID-19 with better performance.

Research on High Speed Communication Method of ELF-EM While Drilling Based on Adaptive Combined Filtering Algorithm

In terms of the electromagnetic wave measurement while drilling,the extremely low frequency electromagnetic(ELF-EM)signal below 20Hz is usually chosen as the downhole data carrier.To improve the transmission rate of ELF-EM signal and the signal to noise ratio(SNR)at the receiving end,the DQPSK modulation was proposed as the modulation method for the communication of electromagnetic wave system.Different from the traditional IQ orthogonal modulation and coherent demodulation methods,the proposed phase selection modulation and correlation algorithm demodulation are easier to implement and more practical.With regard to the communication synchronization,a fast algorithm,which based on the normalized cross-relation number,was used for waveform matching,and the maximum point of the correlation coefficient was used as the starting point of communication synchronization.The communication simulation results show that the proposed DQPSK modulation signal based on the adaptive combined filtering algorithm has better terminal error rate and transmission rate than the traditional modulation method.Under the same carrier frequency and code width,the transmission rate of DQPSK modulation is 4 to 5 times and 2 times that of PPM modulation and 2DPSK modulation respectively.The communication modulation and demodulation modes as well as the decoding algorithm with combined adaptive filter proposed in this paper can effectively solve practical engineering problems.

Inventory of the Thermo-Physiological Behavior of Fabrics—A Review

A comprehensive literature review was performed to create an inventory of thermal-physiological quantities for fabrics from different fiber materials, material blends, and fabric structures. The goal was to derive over-arching concepts that cannot be seen by the individual studies alone. Equations of best fits suggest non-linear changes for fabric thickness, thermal and water-vapor resistance with changes in material blend ratio. Air permeability decreases with increasing fabric density and fabric weight wherein the degree of decrease differs among fabric materials, blend ratio, and fabric structure. Water-vapor transmission rates strongly depend on fabric thickness, material, and blend, but marginally depend on fabric structure as long as the fabric and material thickness remain the same.

Effects of cross-Kerr coupling on transmission spectrum of double-cavity optomechanical system

We theoretically study the transmission spectrum of the cavity field in a double-cavity optomechanical system with cross-Kerr(CK) effect. The system consists of two tunneling coupling optomechanical cavities with a mechanical resonator as a coupling interface. By doping CK medium into the mechanical resonator, CK couplings between the cavity fields and the mechanical resonator are introduced. We investigate the effects of CK coupling strength on the transmission spectrum of the cavity field, including the transmission rate, nonreciprocity and four-wave mixing(FWM). We find that the transmission spectrum of the probe field can show two obvious transparent windows, which can be widened by increasing the CK coupling strength. For the transmission between the two cavity fields, the perfect nonreciprocity and reciprocity are present and modulated by CK coupling and phase difference between two effective optomechanical couplings. In addition, the effects of the optomechanical and CK couplings on FWM show that the single peak of FWM is split into three symmetrical peaks due to the introduction of the CK effect.

A highly reliable embedding algorithm for airborne tactical network virtualization

The evolution of airborne tactical networks(ATNs)is impeded by the network ossification problem.As a solution,network virtualization(NV)can provide a flexible and scalable architecture where virtual network embedding(VNE)is a key part.However,existing VNE algorithms cannot be optimally adopted in the virtualization of ATN due to the complex interference in aircombat field.In this context,a highly reliable VNE algorithm based on the transmission rate for ATN virtualization(TR-ATVNE)is proposed to adapt well to the specific electromagnetic environment of ATN.Our algorithm coordinates node and link mapping.In the node mapping,transmission-rate resource is firstly defined to effectively evaluate the ranking value of substrate nodes under the interference of both environmental noises and enemy attacks.Meanwhile,a feasible splitting rule is proposed for path splitting in the link mapping,considering the interference between wireless links.Simulation results reveal that our algorithm is able to improve the acceptance ratio of virtual network requests while maintaining a high revenue-to-cost ratio under the complex electromagnetic interference.

Research on the Pressure Regulator Effect on a Pneumatic Vibration Isolation System

The pneumatic vibration isolator(PVI)plays an increasingly important role in precision manufacturing.In this paper,aiming to detect the performance of the pressure regulator in the PVI system,a PVI testing system with a pressure regulator is designed and developed.Firstly,the structure of the pneumatic spring is presented and analyzed,and the nonlinear stiffness is obtained based on the ideal gas model and material mechanics.Then,according to the working principle and continuity equations of ideal airflow,a dynamic model of the PVI system with a pressure regulator is established.Through the simulation analysis,the vibration isolation performance is improved with the efficient and precise pressure regulator.The average values of both the vibration velocity and transmission rate decrease when the vibration is set to 4,10,20 and 40 Hz,respectively.The experiments demonstrate the reliability and effectiveness of the pressure regulator.This achievement will become an important basis for future research concerning precision manufacturing.

Collaborative D2D Communication in Relay Networks with Energy Harvesting

Although the collaborative transmission of cellular network and device-to-device(D2D)pairs can improve spectrum utilization,it also results in the matual interference,which may be fatal for low-energy D2D pairs.Based on this,we propose in this paper a collaborative D2D transmission scheme with erergy harvesting(CDTEH)in a relay network,where D2D pairs are allowed to access the spectrum of relay network to accomplish their own transmission.In particular,the relay with energy harvesting is arranged to not only expand cellular transmission range but also assist D2D and cellular users to eliminate the mutual interference.To evaluate the performance,rate-energy(R-E)region is introduced.Based on the model,a data rate maximization problem of D2D pair is formulated,subject to a transmission demand of the cellular user and the optimal solution is acquired.Finally,numerical results are provided to validate the proposed scheme improves the data rate of D2D pair ensuring the cellular transmission requirement.

Transmission risk of asymptomatic SARS-CoV-2 infection:a systematic review and meta-analysis

Background:Global evidence on the transmission of asymptomatic SARS-CoV-2 infection needs to be synthesized.Methods:A search of 4 electronic databases(PubMed,EMBASE,Cochrane Library,and Web of Science databases)as of January 24,2021 was performed.Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA)guidelines were followed.Studies which reported the transmission rate among close contacts with asymptomatic SARS-CoV-2 cases were included,and transmission activities occurred were considered.The trans-mission rates were pooled by zero-inflated beta distribution.The risk ratios(RRs)were calculated using random-effects models.Results:Of 4923 records retrieved and reviewed,15 studies including 3917 close contacts with asymptomatic indexes were eligible.The pooled transmission rates were 1.79 per 100 person-days(or 1.79%,95%confidence interval[CI]0.41%-3.16%)by asymptomatic index,which is significantly lower than by presymptomatic(5.02%,95%CI 2.37%-7.66%;p<0.001),and by symptomatic(5.27%,95%CI 2.40%-8.15%;p<0.001).Subgroup anal-yses showed that the household transmission rate of asymptomatic index was(4.22%,95%CI 0.91%-7.52%),four times significantly higher than non-household transmission(1.03%,95%CI 0.73%-1.33%;p=0.03),and the asymptomatic transmission rate in China(1.82%,95%CI 0.11%-3.53%)was lower than in other countries(2.22%,95%CI 0.67%-3.77%;p=0.01).Conclusions:People with asymptomatic SARS-CoV-2 infection are at risk of transmitting the virus to their close contacts,particularly in household settings.The transmission potential of asymptomatic infection is lower than symptomatic and presymptomatic infections.This meta-analysis provides evidence for predict-ing the epidemic trend and promulgating vaccination and other control measures.Registered with PROS-PERO International Prospective Register of Systematic Reviews,CRD42021269446;https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=269446.

A novel hybrid seed production technology based on a unilateral cross-incompatibility gene in maize

Hybrid seed production technology(SPT)using genic recessive male sterility is of great importance in maize breeding.Here,we report a novel SPT based on a maize unilateral cross-incompatibility gene Zm Ga1F with an extremely low transgene transmission rate(TTR).Proper pollen-specific Zm Ga1F expression severely inhibits pollen tube growth leading to no fertilization.The maintainer line harbors a transgene cassette in an ipe1 male sterile background containing IPE1 to restore ipe1 male fertility,Zm Ga1F to prevent transgenic pollen escape,the red fluorescence protein encoding gene Ds Red2 for the separation of male sterile and fertile seeds,and the herbicide-resistant gene Bar for transgenic plant selection.When the maintainer line is selfed,gametes of ipe1/transgene and ipe1/-genotypes are produced,and pollen of the ipe1/transgene genotype is not able to fertilize female gametes due to pollen tube growth inhibition by Zm Ga1F.Subsequently,seeds of ipe1/ipe1 and ipe1/transgene genotypes are produced at a 1:1 ratio and could be separated easily by fluorescence-based seed sorting.Not a single seed emitting fluorescence is detected in more than 200,000 seeds examined demonstrating that the pollen-tube-inhibition(PTI)-based TTR is lower than what has been reported for similar technologies to date.This PTI-based SPT shows promising potential for future maize hybrid seed production.

Impact of school reopening on pandemic spread: A case study using an agent-based model for COVID-19

This article examines the impact of partial/full reopening of school/college campuses on the spread of a pandemic using COVID-19 as a case study.The study uses an agent-based simulation model that replicates community spread in an urban region of U.S.A.via daily social mixing of susceptible and infected individuals.Data representing population demographics,SARS-CoV-2 epidemiology,and social interventions guides the model's behavior,which is calibrated and validated using data reported by the government.The model indicates a modest but significant increase(8.15%)in the total number of reported cases in the region for a complete(100%)reopening compared to keeping schools and colleges fully virtual.For partial returns of 75%and 50%,the percent increases in the number of reported cases are shown to be small(2.87%and 1.26%,respectively)and statistically insignificant.The AB model also predicts that relaxing the stringency of the school safety protocol for sanitizing,use of mask,social distancing,testing,and quarantining and thus allowing the school transmission coefficient to double may result in a small increase in the number of reported infected cases(2.14%).Hence for pandemic outbreaks from viruses with similar characteristics as for SARS-CoV-2,keeping the schools and colleges open with a modest campus safety protocol and in-person attendance below a certain threshold may be advisable.

Dynamic interconnection component using wireless infrared technology

An efficient dynamic interconnection model using wireless infrared technology and the theory of optical interconnections was constructed to design a dual-channel interconnection component.There were three conditions between the rotating optical field and the stationary optical field:end separation,angle misalignment and lateral mis-alignment.The calculation formulas were given for these three conditions.A dual-channel optical interconnection com-ponent was designed based on the dynamic interconnection model and the data transmission rate of the component was measured.The experimental result showed that the dual-channel optical interconnection component could transmit optical signals across the rotating interface.The maximum transmission rate can reach 2.14 Mb/s.