Frequent Communication Research Articles

Preparation of polyimide films with ultralow dielectric loss at high frequency by reducing intermolecular friction

Due to the rapid development of high frequency and high rate communication technology, polyimide (PI) films with ultra-low dielectric loss (Df) at high frequency, excellent thermal and mechanical properties are urgently needed. A series of PI films with ultra-low Df were prepared by introducing different mesogen units. Among them, one novel PI film with biphenyl liquid-crystal-like units (BAHQ-TFMB) achieve a recorded low Df of 0.00169 (10 GHz) which surpasses previous studies on pure PI bulk films. Importantly, the high degree of collinearity of the friction work (Wf) and Df of PI films (Pearson's r = 0.992) was confirmed, which indicate that Wf among PI macromolecules plays an important role in determining Df of PI films. To reveal underlying reason for reducing the Wf and Df of PI films, the contribution of the degree of orientation and crystallinity of PI films with or without liquid-crystal-like structures were comparative studied. Through a two-dimensional orientation determinant, it is found that increasing the crystallinity of liquid-crystal-like PI films is the main contribution to reducing Wf and corresponding Df of PI films while the orientation of PI films seems to have weak effect. Moreover, BAHQ-TFMB PI film exhibits excellent mechanical properties. The tensile strengths is 145.5 ± 12.0 MPa and Young's moduli is 4.76 ± 0.28 GPa.

Current status and influencing factors of test anxiety of senior one students in Yanji, China: a cross-sectional study.

Examining the current situation of test anxiety among first year senior high school students in Yanji City and investigating the factors that contribute to exam anxiety. Using cluster sampling, a survey was conducted on 1,550 first-year high school students from three high schools in Yanji City in April-May 2023. The survey utilized general information questionnaires, the Minnesota Multiphasic Personality Inventory (MMPI), and the Self-Rating Anxiety Scale (SAS). Logistic regression analysis was used to determine the influencing factors of test anxiety. A total of 1,550 first-year high school students were included in the analysis, with a test anxiety occurrence rate of 79.8%. Test anxiety exhibited statistical differences among different genders, ethnicities, family economic levels, frequency of communication with parents, and relationships with parents (with results of 53.44, 10.42, 17.31, 20.42, 31.95, all p < 0.05). Scores of hypochondriasis (Hs), depression (D), psychasthenia (Pt), paranoia (Pa), psychopathic deviate (Pd), schizophrenia (Sc), and hypomania (Ma) in the 10 clinical personality scales were significantly positively correlated. Logistic regression analysis revealed that gender, ethnicity, frequency of communication with parents, and scores of hypochondriasis (Hs), depression (D), psychasthenia (Pt), paranoia (Pa), and hypomania (Ma) in the 10 clinical personality scales were the main influencing factors for test anxiety in first-year high school students (all p < 0.05). The test anxiety level of high school students in Yanji City is relatively high, with variations in test anxiety levels among students of different genders, ethnicities, parental communication styles, and deviant personality traits. It is recommended that schools and teachers should give more consideration to test anxiety among high school students, particularly targeting those with potential risk factors. Parents should also be more attentive to their children's development and advancement, and improve their family education principles.

Minitype Arrays of Acoustically Actuated Magnetoelectric Antennas for Magnetic Induction Communication

The magnetoelectric (ME) antennas rely on the mechanical movement of magnetic dipoles, making it possible to break the constraints on physical dimensions decided by the wavelength of the electromagnetic wavelength. The ME antennas achieve super-low frequency (SLF) communications with a smaller size to provide a novel solution for long-range, underwater, and underground communications; navigation over the horizon; and geological exploring. As a result, further theoretical research and optimization of ME antennas have been an open challenge for decades. Here, we report on minitype arrays of acoustically actuated ME antenna and their more rigorous equivalent circuits. These arrays of ME antenna adjust amplitude-frequency response through the mechanical regulation method. The mechanical parameters of ME antennas in the arrays result in regulating amplitude-frequency response, such as working frequency, fractional bandwidth, and intensity of magnetic induction. Our work provides a more accurate theoretical model and diverse array form over state-of-the-art ME antenna arrays. The frequency, fractional bandwidth, and magnetic induction strength of the ME antenna arrays were achieved to be adjustable in the ranges of 84 to 181 Hz, 3.9% to 8.3%, and two to four times, respectively. In addition, we have calculated the attenuation characteristics of ME antennas and their minitype arrays in seawater. The results show that the ME antenna array described in this manuscript is able to enhance the radiation intensity and information-loading capability, which has a positive potential for application in SLF communication systems.

Factors influencing academic resilience of master students in China

ABSTRACT This study conducted a survey using the Academic Resilience Scale and the Factors Influencing Academic Resilience Scale among 558 master’s students during the COVID-19 period. The findings reveal that master’s students’ academic resilience is at a moderately high level. Factors such as research self-efficacy, research involvement, academic guidance from supervisors, support from the university, and family support are at moderate levels and significantly influence master’s students’ academic resilience. Additionally, the study found that students with a higher frequency of communication with supervisors and those involved in supervisors’ research projects or leading their own research projects demonstrate higher levels of academic resilience and validated the applicability of an input-process-output model to contemporary master’s students. Given the above findings, it is important to enhance master students’ research investment, effectively provide them with tutor guidance and family support, and concentrate on their negative influence and emotional response to improve their academic resilience.

Reflections on the challenges of conducting an international multicentre randomized controlled trial of balance training in addition to pulmonary rehabilitation and its impact on fall incidence in people with COPD

BackgroundPulmonary rehabilitation (PR) is accepted as standard care for individuals with COPD. We conducted an international, multi-centred randomized controlled trial (RCT) to determine if adding balance training to PR would reduce the incidence of falls in people with COPD. While there have been many trials investigating the effectiveness of PR, few have involved international collaboration. Successful execution of rehabilitation trials requires a significant investment of time, staffing, and resources. With the recent completion of the Balance Training for Fall Reduction in COPD RCT, we report on the design, implementation, and execution of our trial using project management phases. We also highlight our lessons learned for consideration in future multi-centre rehabilitation trials.MethodsThis was a retrospective review of the planning, preparation, timelines, and personnel training involved in the execution of this study using four of the five project management phases described by Farrell et al. in 2010: (1) initiation, (2) planning, (3) execution, and (4) monitoring and controlling. We report descriptive statistics as percentages and counts and summarize our lessons learned.ResultsTen outpatient PR programs in three continents participated. Thirty-one personnel worked on the trial across all sites. Enrolment began in January 2017 and was suspended in March 2020 due to the COVID-19 pandemic. Approximately 1275 patients were screened, 455 (36%) were eligible, 258 (57%) consented, 243 (53%) participated, and 130 (61%) completed the 12-month follow-up assessment. Lessons learned through our experience included (1) ensuring awareness of funder policies and considering the impact on collaborating sites; (2) preparing for the possibility of human resource and program disruptions; (3) anticipating site dropout and having a contingency plan in place; (4) planning and monitoring process measure data before, during, and after trial initiation; (5) ensuring frequent and consistent communication with and between collaborating sites; (6) maximizing features of database platform to ensure data set completeness and controlled data access; and (7) identifying strategies for increasing patient engagement in a high-demand study.ConclusionsWe identify seven lessons learned through our experience conducting an international, multicentre rehabilitation-based RCT. These lessons can provide guidance to other trialists conducting studies with similar logistics and may assist with future trial planning and implementation.

Dynamic event-triggered time-varying formation control for heterogeneous unmanned swarm systems with scaling attacks

This paper addresses the problem of time-varying formation control for heterogeneous unmanned swarm systems (USSs) consisting of multiple unmanned aerial vehicles (UASs) and unmanned surface vehicles (USVs) based on a directional switching topology. Firstly, a novel USSs model is established, involving the effect of multiple network attacks, network bandwidth constraints and input saturation. In particular, a scaling attack model is proposed to account for denial-of-service (DoS) and deception attacks. Secondly, a distributed controller based on a dynamic event triggering mechanism is designed to reduce the communication load by adjusting the communication frequency between individuals, and the Zeno phenomenon is effectively avoided. Finally, the Lyapunov function is used to obtain sufficient conditions for system stability and bounds on the frequency and duration of network attacks. The experiments and comparison results verify the proposed strategy's effectiveness and superiority.

Factors Influencing Participation and Engagement in a Teen Safe Driving Intervention: A Qualitative Study.

(1) Background: Few teen driving safety programs focus on increasing parental engagement with high-risk teen drivers, specifically those with a traffic violation. This study explored parents'/guardians' ('parents') experiences with a teen driving safety program, ProjectDRIVE, including facilitators and barriers to program engagement. (2) Methods: We conducted virtual, semi-structured interviews with parents who completed ProjectDRIVE, which included in-vehicle driving feedback technology and individualized virtual training with parents on effective parent-teen communication. (3) Results: Twenty interviews (with 17 females and three males) were transcribed verbatim and independently coded by three coders using systematic, open, and focused coding. Three major themes were identified: factors influencing a parent's initial decision to participate, factors influencing continued engagement, and perceived benefits of participation. The decision to participate was influenced by these subthemes: parental motivation to help their teen, perceived program usefulness, program endorsement, program incentives, parents' busy schedules, and lack of access to a car/internet. Subthemes impacting continued engagement included enhanced communication skills, teen willingness to engage, strong parental engagement, and teens' other priorities. Perceived benefits included greater self-efficacy in communication, improved communication patterns and frequency, and enhanced parent-teen relationships. (4) Conclusions: These findings may set the foundation for developing and implementing future court-ordered parent-based teen safe driving programs for teens with traffic citations.

Risk Communication on Zoonoses and Antimicrobial Resistance-How Do Exotic Pet Owners Perceive the Communication of Their Veterinarians?

Exotic animals traded and kept as pets can transmit a variety of diseases to humans and other animals, and vice versa. Therefore, it is essential for pet owners, particularly vulnerable groups, to be informed about associated risks. Veterinarians play a crucial role in informing pet owners about health risks associated with zoonotic pathogens and antimicrobial resistance (AMR) and should, therefore, have good communication skills to effectively transfer information to pet owners. Thus, exotic pet owners in Germany were surveyed on animal husbandry, veterinary consultation and risk communication. To evaluate the perception of communication, a self-developed questionnaire was used to derive a communication score. The perception of veterinarian communication received a high average score showing a high level of satisfaction. The duration of the veterinarian-client relationship was associated with better communication perception, and the frequency of communication on zoonoses and AMR was associated with the presence of a permanent veterinarian. However, the results indicated that the frequency of disseminated information on zoonoses and/or AMR from veterinarians was lower than desired by the pet owners. Therefore, more educational material on zoonoses and AMR should be made available, and the awareness concerning risk communication should be increased by further education and training at universities.

Implementation of Virtual Antenatal and Postnatal Urgent Midwifery Visits: Evaluation of a Quality Improvement Initiative.

Women seeking care during the perinatal period often face delays or long waits at healthcare facilities due to lack of providers and/or resources, leading to sub-optimal outcomes. We implemented a program whereby patients with concerns could receive same-day care virtually from a midwife rather than presenting to the clinic or hospital for care. Implementation strategies included virtual training, a staged increase in patient volume, and frequent communication between the midwives via text, email, and monthly meetings. Virtual visits included a variety of complaints, the five most common being to establish care, first-trimester bleeding, nausea and vomiting, mental health concerns, and postnatal breast problems. There was a threefold increase in virtual visits during the first 6 months with 92% of patients not requiring urgent face-to-face follow-up. Midwives were able to provide high-quality telehealth care that met the patients' needs and decreased the demand on hospital-based services. With the growing ubiquity of mobile phones and internet access, this strategy may be effective in providing quality care while decreasing demands on physical infrastructure. More research is needed to assess acceptability in other contexts. Reproducibility in low-resource settings may be limited if women lack access to video conferencing on phones or laptops.

Single-cell sequencing reveals the transcriptional alternations of 17β-estradiol suppressing primordial follicle formation in neonatal mouse ovaries.

Estrogen has been implicated in multiple biological processes, but the variation underlying estrogen-mediated primordial follicle (PF) formation remains unclear. Here, we show that 17β-estradiol (E2) treatment of neonatal mice led to the inhibition of PF formation and cell proliferation. Single-cell RNA sequencing (scRNA-seq) revealed that E2 treatment caused significant changes in the transcriptome of oocytes and somatic cells. E2 treatment disrupted the synchronised development of oocytes, pre-granulosa (PG) cells and stromal cells. Mechanistically, E2 treatment disrupted several signalling pathways critical to PF formation, especially down-regulating the Kitl and Smad1/3/4/5/7 expression, reducing the frequency and number of cell communication. In addition, E2 treatment influenced key gene expression, mitochondrial function of oocytes, the recruitment and maintenance of PG cells, the cell proliferation of somatic cells, as well as disordered the ovarian microenvironment. This study not only revealed insights into the regulatory role of estrogen during PF formation, but also filled in knowledge of dramatic changes in perinatal hormones, which are critical for the physiological significance of understanding hormone changes and reproductive protection.

An edge‐based event‐triggered delayed distributed algorithm for economic dispatch in smart grids

AbstractThis paper presents an edge‐based event‐triggered delay distributed algorithm for solving the economic dispatch problem (EDP) in smart grids. The objective of the EDP is to minimize the total generation cost by allocating power to individual generators, each with its local generation constraint. To save the overhead of communication resources between agents, an edge‐based event‐triggered mechanism is suggested. By setting distinct triggering thresholds for each communication edge, the agent may efficiently regulate the communication frequency among all neighbors. However, in practice, owing to the instability of the network, the agent may receive information regarding its neighbors, leading to communication lags for every communication link. The virtual agent technique and double‐stochastic matrix augmentation technique provide an equivalent delay‐free EDP. It is demonstrated that the proposed algorithm can asymptotically converge to the global optimal solution as long as the communication delay is arbitrary, time‐varying, and random, but bounded. Objective and clear evidence is provided through a case study in smart grids to verify the algorithm's feasibility.

Dynamic event‐triggered control of 2‐D continuous systems in Roesser model

AbstractIn this paper, a dynamic event‐triggered control problem is discussed for 2‐D continuous systems by the Roesser model. In order to reduce communication frequency and avoid dependence on global information, a dynamic event‐triggered mechanism is constructed, which is more flexible than some existing event‐triggered schemes with fixed event‐triggered thresholds. Utilizing the dynamic event‐triggered mechanism, a state feedback controller is designed. By constructing a 2‐D Lyapunov function, sufficient conditions expressed in terms of linear matrix inequalities (LMIs) are firstly established such that the 2‐D system is asymptotically stable with a disturbance attenuation performance. It is also proved that the Zeno phenomenon is excluded. Finally, two examples are provided to illustrate the effectiveness of the proposed method.

A model for preventing radio interference in the communication system of unmanned aerial vehicles

Problem statement. The communication network of unmanned aerial vehicles (UAVs) has proven to be a promising model capable of operating independently and as a repeater to increase coverage and communication efficiency. However, densely distributed ground base stations with common communication frequencies inevitably generate interference within the transmission channel. The influence of interference can be effectively eliminated by implementing optical communication in free space in the communication network of an unmanned aerial vehicle. Goal. Development of a modal for effective elimination of radio interference for unmanned aerial vehicles through the use of a mixed millimeter-wave radio frequency communication system. Results. The simulation results show that the proposed network significantly increases the probability of troubleshooting and achieves an increase in the signal-to-noise ratio by approximately 4.6 dB at an average frequency of character errors, especially in scenarios where radio frequency lines are subject to severe interference or unfavorable weather conditions, unlike a fully radio frequency communication network. Practical significance. Improved communication reliability for UAV systems with an effective signal-to-noise ratio reduces the likelihood of packet loss and the bit error rate (BER) of transmitted data.

Unblocking COVID-19 impact on stock returns

COVID-19 altered global economics activities during the pandemic period and still affects the stock returns. As worldwide resulted, this shift has changed the Pakistani stock returns activities. This study unfolds the impact of COVID-19 on stock returns frequency of pharmaceutical, power generation, technology and communication, and food sectors in Pakistan. To examine the relationship of above-mentioned sectors with stock returns, data were evaluated through event window that included the event dates of the 150-day and 60-day estimating period. COVID-19 has a considerable detrimental influence on stock returns during the post-event interval. The study findings showcase significant negative relationship with stock returns of the above-mentioned sectors. However, the results are contradictory during the second wave of coronavirus infection. Furthermore, the study also substantiates that COVID-19 has significantly affected the stock market performances of Pakistan. Still, the impact on the stock market performances was only for a short period, and it diminished in the second wave of COVID-19 spread in Pakistan. The findings contribute to the research on the stock returns of selected sectors and commodity market impact of a pandemic by providing empirical evidence that COVID-19 has spill-over effects on stock market. This result also helps investors in assessing the trends of the stock and commodity markets during the pandemic outbreak. Managers are encouraged to modify their strategies to maintain stocks of the firm for better performance under the direction of study findings.

Research on the Strategy of Integrating Chinese Traditional Culture into College English Teaching

With the deepening of globalization and the increasing frequency of cross-cultural communication, the importance of English as an international language is obvious. College English teaching plays a decisive role in China s higher education system, which is not only the key course to promote the development of students applied English ability, but also an important means to cultivate their international vision and cross-cultural communication ability. But at present, college English teaching often pays too much attention to the cultivation of language skills, but neglects the cultural inheritance and integration. This situation, to some extent, restricts students understanding and perception of the deep cultural connotation of English lauguage itself. The purpose of this study is to explore the effective combination of Chinese traditional culture and college English teaching, so as to promote the improvement of teaching quality and cultivate high-quality talents with solid English skills and a deep understanding of Chinese and Western culture.

Novel Dynamic Event-Triggered Consensus Control of Multiagent Systems With Markovian Switching Topologies Under DoS Attacks.

This article focuses on the issue of novel dynamic event-triggered consensus control of multiagent systems (MASs) with denial-of-service (DoS) attacks. Different from the conventional Markovian switching topologies, the generally uncertain semi-Markovian (GUSM) switching topologies with partially unknown elements and time-dependent uncertainties are constructed for the leader-following MASs by considering the equipment performance and external uncertain environment influence. To save communication resources, the novel dynamic memory event-triggered strategy (DMETS) is presented to decrease the frequency of communication between agents. Some secure consensus control criteria are established for the MASs with GUSM switching topologies and DoS attacks due to the potential system communication disruption caused by attackers. Finally, two physical system examples are designed to prove the effectiveness of the presented method.

Data Immunity in Near Field Radio Frequency Communication Systems—NFC as an Aspect of Electromagnetic Information Security

Data Immunity in Near Field Radio Frequency Communication Systems—NFC as an Aspect of Electromagnetic Information Security

Composite error event-triggered-based finite-time safe formation control of underactuated vessels

For the problems of limited communication bandwidth and frequent triggering of actuators during the formation navigation, comprehensively considering the safety performance and coordinated control performance, a novel composite error event-triggered-based formation control strategy is proposed. Firstly, design an event-triggered-based finite-time extended state observer, which can not only quickly estimate the compound disturbances and velocity information simultaneously, but also reduce the communication frequency between sensor and observer. Secondly, considering the communication frequency and coordinated control performance of the whole formation system, a composite error based on the state information of adjacent underactuated vessels is defined, and it is used as a factor of the event-triggered mechanism. Then, by combining the exponential potential energy function, the composite error event-triggered-based formation controller is designed. And through stability analysis, we known that all signals of the system are uniformly ultimately bounded. Furthermore, the Zeno phenomenon that exists in event-triggered control can also be avoided completely. Finally, through simulation results and comparative analysis, the effectiveness of the composite error event-triggered-based formation control scheme for safe navigation control and reducing communication frequency and triggering frequency has been verified.

Determining carrier frequency for implantable human body communication based on transmission efficiency–electromagnetic interference trade-off

This study proposes a novel methodology for determining the optimal carrier frequency for implantable human body communication (HBC) by focusing on the trade-off between transmission efficiency and electromagnetic interference (EMI) robustness. Traditional radio communication technologies use high-frequency bands, which pose some challenges, such as increased power consumption, EMI with other devices, and security risks. Implantable HBC is a promising alternative, wherein the human body is used as a transmission medium. Through phantom experiments simulating the human abdomen, we assess the transmission characteristics of implantable HBC between an abdominal neurostimulator and an external controller across a frequency range of 1–100 MHz. Results revealed that maximum transmission gain was achieved at 37.2 MHz. Moreover, rapid signal attenuation occurred beyond a minimal distance from the skin, indicating enhanced communication efficiency, reduced EMI, and enhanced information security. An evaluation index (EI) was also proposed to quantitatively assess the balance between transmission efficiency and EMI and determine an appropriate carrier frequency for specific implantable HBC applications. This study advances the field of implantable medical devices by optimizing communication performance while addressing key challenges in EMI and security.

Prediction model for very high frequency communication interruption based on random forest regression algorithm

Abstract The onboard Very High Frequency (VHF) communication is susceptible to interruption due to antenna radiation signal blockage caused by the aircraft body at certain angles resulting from changes in the aircraft’s attitude. To establish a prediction model for communication interruptions, data on the radiation power level, attitude angle 1, and attitude angle 2 of the antenna were initially collected. Subsequently, a machine learning model was constructed to predict the radiation power at two specific frequency points of a VHF communication antenna for helicopters. The model was built by using the random forest (RF) regression algorithm. For the prediction model of frequency point 1, the Goodness of Fit (R2) and Mean Squared Error (MSE) were 0.997 and 0.023, respectively, with feature importance scores of 0.98 for attitude angle 1 and 0.02 for attitude angle 2. For the prediction model of frequency point 2, the R2 and MSE were 0.999 and 0.008, respectively, with feature importance scores of 0.91 for attitude angle 1 and 0.09 for attitude angle 2. The study results indicate that the variation in attitude angle 1 significantly impacts the antenna’s radiation power. The RF regression model can effectively predict the onboard VHF communication capability, thereby providing technical support for reducing the potential risk of communication interruption.