Transmission Mode Research Articles

Dynamical analysis and optimal control of an age‐structured epidemic model with asymptomatic infection and multiple transmission pathways

The diversity of transmission modes and the heterogeneity of populations in the transmission of infectious diseases are issues that have to be faced in the current disease protection. In this paper, an infectious disease model incorporating age structure and horizontal and environmental spread, along with asymptomatic infection, is proposed to describe diversification of disease transmission routes and population heterogeneity. The expression of the basic reproduction number is derived by a linear approximation method, and it is concluded that if , the disease‐free steady state is globally asymptotically stable; if , the model has a unique endemic steady state which is locally asymptotically stable under certain conditions. Further, the uniform persistence of disease is proved using the persistence theory of the infinite‐dimensional dynamical system when . In additional, the issue of optimal control problem according to this model is investigated, and the representation of optimal control with respect to state variables and adjoint variables is obtained which also imply the existence and uniqueness of optimal control. Finally, numerical simulations are carried out to interpret the theoretical results and to discuss the impact of age and control measures in disease transmission.

Design of photonic crystal fiber supporting 190 orbital angular momentum modes with low nonlinearity coefficient

A new photonic crystal fiber is proposed for the transmission of more orbital angular momentum modes with a rectangular air hole arrangement to increase the cladding air-filling rate. The results reveal that the fiber can support 190 orbital angular momentum modes in the C+L band, with the topological charge ordering up to 48, and the effective refractive index difference between adjacent eigenmodes is above 10−3. The effective mode area of all the eigenmodes is larger than 208.02 μm2, the nonlinearity coefficient is less than 0.43 W−1∙km−1, the confinement loss reaches up to 10−12-10−8 dB/m, the dispersion is flat and the minimum dispersion change is 3.15 ps∙nm−1∙km−1, with mode purity greater than 97.4%. Compared to existing typical orbital angular momentum transmission photonic crystal fibers, this fiber can support more orbital angular momentum modes for most purposes with lower nonlinearity coefficient, higher mode purity, better propagation characteristics but simpler structure. The highest nonlinearity coefficient is reduced by at least 0.3 W−1∙km−1 compared to existing typical orbital angular momentum transmission photonic crystal fibers. The effect of fabrication errors on the transmission quality of orbital angular momentum modes is also discussed, and the results reveal that the effect on mode transmission quality is small at 1–2% variations of air holes. Therefore, this photonic crystal fiber is promising in high-capacity communication systems.

A novel bifunctional metasurface based on independent control of transmission and reflection amplitudes and phases

ABSTRACT A novel bifunctional metasurface (MS) operating at two frequencies is proposed to manipulate reflected and transmitted waves independently. The element is composed of a slot sandwiched by two C-shape spilt rings (CSRRs). The middle layer is the metal sheet etched the slots, and it is used to select polarization mode of reflection and transmission. Also, it isolates the reflection and transmission elements and eliminates the coupling between them. Therefore, the reflection or transmission amplitude and phase of the proposed MS can be regulated by the corresponding single metal layer compared with the current bifunctional elements. This is helpful to shorten design time. Also, a higher transmission amplitude is achieved with fewer substrate layers and lower profile. The reflection and transmission mode operate at 17.6 GHz and 12.6 GHz, respectively. As a proof of concept, a full-space multibeam generator is validated both numerically and experimentally and a full-space bifocal metalens is demonstrated numerically. The proposed MS provides a new kind of low cost, lightweight, and easily modularized planar devices for microwave applications.

A heteropolarized single layer reflect‐transmit‐array antenna

AbstractA novel reflect‐transmit‐array antenna is proposed in this paper, in which a single‐layer heteropolarized element with a thickness of 0.1 at 11 GHz, consisting of only two layers of metal patches printed on a dielectric substrate and six metal vias, can integrate reflection and transmission modes in the same frequency band by reasonably distributing the positions of the reflection and transmission parts in the element. We designed, fabricated, and measured the reflect‐transmit‐array antenna with an aperture of 501.2 mm2. At 11 GHz, the maximum gain of reflection is 17.7 dB, and the peak gain of transmission is 20.4 dB, indicating that this scheme has good application prospects in bidirectional wireless communication.

Investigation of Excitation Modes in Al2O3-YAG Phosphor Ceramics for High-Power Laser-Driven Lighting

The performance of laser-driven white light can vary significantly depending on the excitation mode. To attain desirable application performance of color converters in laser lighting, the excitation mode must be selected carefully. In this work, to understand the effect of the excitation mode on the performance of color converters, a detailed study was conducted on the heat dispersion, luminescence, and color quality of Al2O3-YAG:Ce phosphor ceramics in both transmissive and reflective modes. The relationship between ceramic porosity and scattering performance has also been analyzed by studying the beam expansion ratio. The results demonstrate that the phosphor ceramics in reflective mode exhibit superior heat dissipation capabilities and can withstand higher power laser excitation compared to the transmissive mode, while the light uniformity is relatively poorer due to the specular reflection. Therefore, in situations where a uniform light is not necessary, reflective color converters are more suitable for achieving superior luminance and luminous efficacy. Finally, a laser-driven white light device with a luminous flux of 1206 lm, a luminous efficacy of 241.2 lm W−1, and a CCT of 5749 K has been realized using Al2O3-YAG:Ce phosphor ceramic in reflective mode, which can be applied for automotive headlights.

Searching for common patterns in parasite ecology: species and host contributions to beta-diversity in helminths of South African ungulates and fleas of South American rodents

We searched for common patterns in parasite ecology by investigating species and host contributions to the beta-diversity of infracommunities (=assemblages of parasites harboured by a host individual) in helminths of three species of South African ungulates and fleas of 11 species of South American rodents, assuming that a comparison of patterns in distinctly different parasites and hosts would allow us to judge the generality or, at least, commonness of these patterns. We used data on species’ composition and numbers of parasites and asked whether (i) parasite species’ attributes (life cycle, transmission mode, and host specificity in helminths; possession of sclerotized combs, microhabitat preference, and host specificity in fleas) or their population structure (mean abundance and/or prevalence) and (ii) host characteristics (sex and age) affect parasite and host species’ contributions to parasite beta-diversity (SCBD and HCBD, respectively). We found that parasite species’ morphological and ecological attributes were mostly not associated with their SCBD. In contrast, parasite SCBD, in both ungulates and rodents, significantly increased with either parasite mean abundance or prevalence or both. The effect of host characteristics on HCBD was detected in a few hosts only. In general, parasite infracommunities’ beta-diversity appeared to be driven by variation in parasite species rather than the uniqueness of the assemblages harboured by individual hosts. We conclude that some ecological patterns (such as the relationships between SCBD and parasite abundance/prevalence) appear to be common and do not differ between different host-parasite associations in different geographic regions, whereas other patterns (the relationships between SCBD and parasite species’ attributes) are contingent and depend on parasite and host identities.

IJCM_427A : Profile of HIV Positive Attendees at I.C.T.C. Attavar - A Retrospective Study

Background: Acquired Immunodeficiency Syndrome (AIDS) continues to pose a significant public health threat worldwide, with India experiencing a substantial burden. Integrated Counseling and Testing Centers (ICTCs) play a pivotal role in addressing HIV/AIDS by providing crucial healthcare access and dispelling misconceptions surrounding the disease. Objectives: To study the profile of PLHIV patients attending ICTC centre. Methodology: This descriptive record-based study was conducted at the ICTC of Kasturba Medical College Hospital, Mangalore, aiming to profile HIV-positive attendees. Data on sociodemographic characteristics, mode of transmission, referrals, and counseling practices were collected from records of 137 seropositive attendees using convenient sampling. Statistical analysis was conducted using SPSS version 11.5. Results: The study revealed that most attendees were male (63.5%), married (78.8%), and aged 40 and above (40.1%). Heterosexual contact was identified as the primary mode of transmission (95.6%), with no cases attributed to blood transfusion. Private health facilities were the primary referrers (72.9%), and ICTC mainly referred patients to Antiretroviral Therapy (ART) centers (72.3%). Post-test counseling included spousal testing (33.6%) and condom counseling (90.5%), with limited condom uptake (18.9%) and follow-up of seropositive attendees (35.8%). Conclusion: The study underscores the critical role of ICTCs in HIV/AIDS management, highlighting trends in attendee profiles, transmission modes, referrals, and counseling practices. It emphasizes the necessity for targeted interventions to enhance follow-up and promote condom usage, alongside continued efforts to mitigate HIV transmission.

Wireless Body Area Nanonetworks via Vascular Molecular Communication.

Advancements in biotechnology and molecular communication have enabled the utilization of nanomachines in Wireless Body Area Networks (WBAN2) for applications such as drug delivery, cancer detection, and emergency rescue services. To study these networks effectively, it is essential to develop an ideal propagation model that includes the channel response between each pair of in-range nanomachines and accounts for the interference received at each receiver node. In this paper, we employ an advection-diffusion equation to obtain a deterministic channel matrix through a vascular WBAN2. Additionally, the closed forms of inter-symbol interference (ISI) and co-channel interference (CCI) are derived for both full duplex (FDX) and half duplex transmission (HDX) modes. By applying these deterministic formulations, we then present the stochastic equivalents of the ideal channel model and interference to provide an innovative communication model by simultaneously incorporating CCI, ISI, and background noise. Finally, we evaluate the results with numerous experiments and use signal-to-interference-plus-noise ratio (SINR) and capacity as metrics.

ArguteDUB: Deep Learning Based Distributed Uplink Beamforming in 6G-Based IoV

In the last decade, MIMO spatial multiplexing and distributed beamforming play a significant role in improving data throughput through cooperative transmission. It has been widely used in wireless communication, especially in 6 G. However, the distributed uplink beamforming is still an open problem in highly dynamic environments. However, the proposed 6 G technology represents the further integration of deep learning and wireless communication. In this paper, we propose Argute Distributed Uplink Beamforming (ArguteDUB), which uses a feedback algorithm with an offline-trained deep learning model to implement highly dynamic distributed uplink beamforming for the Internet of Vehicles (IoV) in 6 G. Specifically, each vehicle enables the base station (BS)/access point (AP) to separate different channel state information (CSI) by inserting orthogonal sequences into the sending data. The BS adopts deep learning to filter the noise and predict the beamforming weight to achieve phase synchronization. Unlike traditional distributed uplink beamforming, ArguteDUB can be adapted to the highly dynamic time-varying channels. The simple network structure ensures the fast response of ArguteDUB. In addition, we make ArguteDUB Orthogonal Frequency Division Multiplexing (OFDM) compatible so that it can be easily deployed in 6 G networks. Our evaluation shows that ArguteDUB has an signal-to-noise ratio (SNR) gain of about 5 dB to 5.3 dB over the single vehicle transmission mode.

Designing a Secure and Scalable Service Agent for IoT Transmission through Blockchain and MQTT Fusion

With the rapid development of the Internet of Things (IoT) in recent years, many IoT devices use communication systems to transmit data. Data packets are inevitably at risk of tampering during data transmission, which can lead to information errors and damage during communication. Since IoT terminals are often operated under human supervision, it is essential to improve and ensure the transmission of information, avoid data tampering, and ensure the accuracy of packet transmission. This research successfully improves the message transmission method of IoT communication and the communication model by combining it with blockchain architecture. Combining communication protocols with blockchain serial connections eliminates the need to control operating and managing processes. By replacing message transmission with coverage, the reliability of data transmission in the IoT communication system is improved, and the flexibility of the data transmission process is enhanced. Through practical verification through experimentation, the study successfully improved the incapability of effectively constructing a cross-coded message transmission mode in the Message Queuing Telemetry Transport (MQTT) communication protocol, removed a single layer of encryption rule, and created an encryption mode capable of providing complex arrangement organization.

Zoonotic potential of brucellosis in marine mammals

Brucellosis in marine mammals (cetacean and pinnipeds) has emerged in a very significant way during the last two decades. Currently Brucella ceti and Brucella pinnipedialis are the two recognized species in marine mammals, but available information is still limited. Several genotypes have been identified, and studies on the relationship between sequence type (ST) and organ pathogenicity or tropism have indicated differences in pathogenesis between B. ceti sequences in cetaceans. The zoonotic potential of this disease is based on the identification of the main sources of introduction and spread of Brucella spp. in the marine environment as well as on the factors of exposure of marine mammals and humans to the bacteria. This article is a bibliographical review on marine mammal brucellosis, including the features, sources and transmission modes of each Brucella species, as well as their potential pathogenicity in animals and humans. Different genotypes of marine Brucella spp have been isolated from marine mammal species but without any evidence of pathology induced by these bacteria. Associated lesions are variable and include subcutaneous abscesses, meningo-encephalomyelitis, pneumonia, myocarditis, osteoarthritis, orchitis, endometritis, placentitis and abortion. The isolation of marine B. spp from marine mammal respiratory parasites associated to lung injury has raised the intriguing possibility that they may serve as a vector for the transmission of this bacterium.The severity of marine B. spp remains unknown due to the lack of an estimate of the prevalence of this disease in marine mammals. The number of suspected human cases is still very limited. However, by analogy with other germs of the genus Brucella responsible for abortion in ruminants and for a febrile and painful state in human beings, prevention measures are essential. The significant increase in the number of strandings coupled with a high seroprevalence in certain species of marine mammals must be considered for people in direct or indirect contact with these animals. Ongoing epidemiological monitoring combined with extensive post-mortem examinations (necropsy, bacteriology and sequencing) of all species of stranded marine mammals would deepen knowledge on the zoonotic potential of marine Brucella species.

A δ-free approach to quantization of transmission lines connected to lumped circuits

The quantization of systems composed of transmission lines connected to lumped circuits poses significant challenges, arising from the interaction between continuous and discrete degrees of freedom. A widely adopted strategy, based on the pioneering work of Yurke and Denker, entails representing the lumped circuit contributions using Lagrangian densities that incorporate Dirac δ-functions. However, this approach introduces complications, as highlighted in the recent literature, including divergent momentum densities, necessitating the use of regularization techniques. In this work, we introduce a δ-free Lagrangian formulation for a transmission line capacitively coupled to a lumped circuit without the need for a discretization of the transmission line or mode expansions. This is achieved by explicitly enforcing boundary conditions at the line ends in the principle of least action. In this framework, the quantization and the derivation of the Heisenberg equations of the network are straightforward. We obtain a reduced model for the lumped circuit in the quantum Langevin form, which is valid for any coupling strength between the line and the lumped circuit. We apply our approach to an analytically solvable network consisting of a semi-infinite transmission line capacitively coupled to an LC circuit and study the behavior of the network as the coupling strength varies.

Transmission dynamics of Zika virus with multiple infection routes and a case study in Brazil

The Zika virus (ZIKV) is a serious global public health crisis. A major control challenge is its multiple transmission modes. This paper aims to simulate the transmission patterns of ZIKV using a dynamic process-based epidemiological model written in ordinary differential equations, which incorporates the human-to-mosquito infection by bites and sewage, mosquito-to-human infection by bites, and human-to-human infection by sex. Mathematical analyses are carried out to calculate the basic reproduction number and backward bifurcation, and prove the existence and stability of the equilibria. The model is validated with infection data by applying it to the 2015–2016 ZIKV epidemic in Brazil. The results indicate that the reproduction number is estimated to be 2.13, in which the contributions by mosquito bite, sex and sewage account for 85.7%, 3.5% and 10.8%, respectively. This number and the morbidity rate are most sensitive to parameters related to mosquito ecology, rather than asymptomatic or human-to-human transmission. Multiple transmission routes and suitable temperature exacerbate ZIKV infection in Brazil, and the vast majority of human infection cases were prevented by the intervention implemented. These findings may provide new insights to improve the risk assessment of ZIKV infection.

Collaborative communication-based ocean observation research with heterogeneous unmanned surface vessels

Unmanned surface vehicles (USVs) are crucial in ensuring maritime safety and observation, attracting widespread attention and research. However, a single USV exhibits limited performance and cannot effectively observe complex marine environments. In contrast, clusters of USVs can collaborate to execute complex maritime tasks, thereby enhancing the overall operational efficiency. USVs typically form heterogeneous clusters by combining vehicles with varying maneuverabilities and communication network capabilities. This has sparked an increased interest in cooperative communication research within heterogeneous USV clusters. The heterogeneous USVs discussed in this paper share the same dynamic model; however, they differ in dynamic parameters and communication capabilities. First, this study establishes a three-degree-of-freedom motion mathematical model for an underdriven USV considering environmental interference. It estimates the dynamic parameters of four USVs and evaluates their communication abilities, laying the foundation for researching the cooperative control of heterogeneous USV clusters and their application in Ocean Observation. Next, the communication capability of the USVs is assessed by studying the communication mode and signal transmission loss within the USV clusters. This study investigates the problem of cooperative communication in USV cluster formation, starting with the communication delay of USV clusters under a directed switching topology. Finally, a coherent formation controller is designed under a switching communication topology to address the dynamic transformation of communication topologies within heterogeneous USV clusters. This verifies that heterogeneous USV clusters can seamlessly form and maintain formation shapes during communication topology transformations through formation simulation experiments involving four heterogeneous USVs was 22% higher than that of dispersed control topology structures. This study provides a solid foundation for future investigations into the cooperative control of heterogeneous USV clusters and their applications in marine observations.

Application of Python-Based Abaqus Secondary Development in Laser Shock Forming of Aluminum Alloy 6082-T6.

Aluminum alloy 6082-T6 is an important material for manufacturing the outer skin of high-speed trains, and laser shock forming can realize the rapid forming of complex-shaped plates. In order to improve the efficiency of the simulation modeling of laser shock forming for aluminum alloy 6082-T6, Python scripting language was used for the secondary development of Abaqus. A plugin was utilized to simulate and analyze the laser shock forming process of aluminum alloy 6082-T6. The coordinates of the plate after laser impact molding were measured using a coordinate measuring machine to calculate the arc bow height of the plate. The accuracy of the simulation model was verified by comparing with the simulation results. The deformation characteristics of plastic strain and arc height of aluminum alloy 6082-T6 under different laser process parameters were analyzed. The simulation plugin has a concise interface, high operability, and accurate results with the other parameters unchanged. When the laser energy is 5 J, 6 J, and 7 J, the corresponding arc heights are 5.9 mm, 6.6 mm, and 7.2 mm, respectively. As the thickness of the sheet increases, the deformation changes from concave at 1 mm to convex at 2 mm, 3 mm, 4 mm, and 5 mm. As the spot size increases from 1 mm to 5 mm, the transmission mode of the shock wave gradually changes from spherical wave to planar wave, and the arc height of the sheet increases from 4.6 mm to 8.2 mm. With the increase in the spot overlap rate, the impact area accumulates residual stress, and the arc height of the sheet is 5.7 mm, 6.6 mm, 7.3 mm, and 8.5 mm, respectively. The secondary development of ABAQUS 2021 using Python 3.6 scripting language has improved the efficiency of simulation modeling and provided reference for rapidly predicting the deformation characteristics of aluminum alloy 6082-T6 under different laser process parameters.

Configuration of the Power Reflux Hydro-Mechanical Transmission System

The hydro-mechanical transmission system (HMTS) operates either in power split transmission mode (PSTM) or power reflux transmission mode (PRTM). Although PRTM is often ignored as a transition mode, this study reveals that the HMTS operating in the PRTM can accumulate the power input from the power source in the form of reflux power (in some references, scholars also refer to the reflux power as circulating power), thereby enabling the HMTS to exhibit a similar transmission performance as hydrodynamic transmission systems. Accordingly, this study applies the PRTM to the starting of construction vehicles and refers to the HMTS operating only in the PRTM as the power reflux hydro-mechanical transmission system (PHTS). By analyzing the internal relationship between the configuration and the power flow, transmission characteristics, energy storage mechanism, and energy loss mechanism of the PHTS, the optimal PHTS configuration suitable for construction vehicles was explored. The results indicate that reasonable configurations can enable the PHTS to significantly improve the efficiency of the construction vehicle transmission system, reducing energy consumption while ensuring power performance. Expanding the displacement ratio control range of the hydraulic speed regulation mechanism and combining the PRTM with the PSTM in an orderly manner can widen the high-efficiency range of the vehicle transmission system without increasing the number of vehicle gears.

Ultrafast Dynamics, Optical Nonlinearities, and Chemical Sensing Application of Free-Standing Porous Silicon-Based Optical Microcavities.

The present work demonstrates the ultrafast carrier dynamics and third-order nonlinear optical properties of electrochemically fabricated free-standing porous silicon (FS-PSi)-based optical microcavities via femtosecond transient absorption spectroscopy (TAS) and single-beam Z-scan techniques, respectively. The TAS (pump: 400 nm, probe: 430-780 nm, ∼70 fs, 1 kHz) decay dynamics are dominated by the photoinduced absorption (PIA, lifetime range: 4.7-156 ps) as well as photoinduced bleaching (PIB, 4.3-324 ps) for the cavity mode (λc) and the band edges. A fascinating switching behavior from the PIB (-ve) to the PIA (+ve) has been observed in the cavity mode, which shows the potential in ultrafast switching applications. The third-order optical nonlinearities revealed an enhanced two-photon absorption coefficient (β) in the order of 10-10 mW-1 along with the nonlinear refractive index (n2) in the range of 10-17 m2 W-1. Furthermore, a real-time sensing application of such FS-PSi microcavities has been demonstrated for detecting organic solvents by simultaneously monitoring the kinetics in reflection and transmission mode.

Enhancement of Transverse Magneto-Optic Kerr effect in subwavelength all-dielectric guided mode gratings with a buffer layer

We demonstrate a simple subwavelength all-dielectric photonic device with greatly enhanced transverse magneto-optical Kerr effect (TMOKE) in the transmission mode. The concept utilizes the diffracted waves of the periodic magnetic material bismuth-substituted iron garnet grating to excite the guided mode in the planar waveguide, and adds a buffer layer under the all-dielectric guided mode grating. In the study, it was found that increasing the refractive index of the buffer layer can reduce the coupling between the grating and the waveguide, so that full width at half maximum of the transmission spectra can be narrowed, and the value of TMOKE can be greatly enhanced up to 1.82. It is worth noting that the TMOKE value of the guide mode grating with buffer layer is 3 times that of those without buffer layer, thus opening up different avenues for designing efficient, integrated and low-loss magneto-optical devices. Enhanced TMOKE has great potential for applications such as biosensing/high-resolution sensing, magneto-optical modulation and magnetic measurement.

Optimized Two-Tier Caching with Hybrid Millimeter-Wave and Microwave Communications for 6G Networks

Data caching is a promising technique to alleviate the data traffic burden from the backhaul and minimize data access delay. However, the cache capacity constraint poses a significant challenge to obtaining content through the cache resource that degrades the caching performance. In this paper, we propose a novel two-tier caching mechanism for data caching on mobile user equipment (UE) and the small base station (SBS) level in ultra-dense 6G heterogeneous networks for reducing data access failure via cache resources. The two-tier caching enables users to retrieve their desired content from cache resources through device-to-device (D2D) communications from neighboring users or the serving SBS. The cache-enabled UE exploits millimeter-wave (mmWave)-based D2D communications, utilizing line-of-sight (LoS) links for high-speed data transmission to content-demanding mobile UE within a limited connection time. In the event of D2D communication failures, a dual-mode hybrid system, combining mmWave and microwave μWave technologies, is utilized to ensure effective data transmission between the SBS and UE to fulfill users’ data demands. In the proposed framework. the data transmission speed is optimized through mmWave signals in line-of-sight (LoS) conditions. In non-LoS scenarios, the system switches to μWave mode for obstacle-penetrating signal transmission. Subsequently, we propose a reinforcement learning (RL) approach to optimize cache decisions through the approximation of the Q action-value function. The proposed technique undergoes iterative learning, adapting to dynamic network conditions to enhance the content placement policy and minimize delay. Extensive simulations demonstrate the efficiency of our proposed approach in significantly reducing network delay compared with benchmark schemes.

Photonic crystal fiber sensors to excite surface plasmon resonance based on elliptical detection channels are used for highly sensitive magnetic sensing

To improve the detection performance of fiber optic magnetic field sensors a new photonic crystal fiber (PCF) based on surface plasmon resonance (SPR) was designed and investigated. The designed sensor uses an elliptical detection channel, and the modal transmission characteristics and magnetic field sensing characteristics of this fiber optic sensor are analyzed using the full vector finite element method (FVFEM). In addition, the effect of the detection channel on the detection accuracy at different curvatures was investigated. Compared with previous optical fiber magnetic field (MF) sensors, the designed sensor meets the requirements of both refractive index (RI) and MF measurements, and the MF sensitivity, RI sensitivity, and amplitude sensitivity (AS) of the sensor reach 0.739 nm/Oe, 12043.8 nm/RIU, and 754.88RIU−1, respectively. The designed sensor expands the application range of optical fiber sensors and reduces the cost. It has great potential for application in complex environments.