Millimeter-wave (mmWave) communication with multi-gigahertz bandwidth availability enables much higher capacity and transmission rate than conventional microwave communications. However, mmWave signals suffer from propagation-related shortcomings. The flexibility of UAV can compensate most the deficiencies signals, preserve its advantages, provide more opportunities. In this article, we present current state art, research opportunities, challenges for communication. We channel...

Unmanned aerial vehicles (UAVs) have recently attracted tremendous attentions in both industries and academic communities. Thanks to the high mobility flexibility, UAVs can be deployed many scenarios provide various types of services. In these scenarios, position must timely accurately acquired avoid UAV collisions realize millimeter-wave beamforming. Particle swarm optimization (PSO) is a potential approach fulfill localization under GPS-denied environment. However, it has drawbacks...

Reconfigurable intelligent surface (RIS) has recently emerged as a promising paradigm for future cellular networks. Specifically, due to its capability in reshaping the propagation environment, RIS was introduced address blockage issue millimeter-wave (mmWave) or even terahertz communications. The deployment of RIS, however, complicates system architecture and poses significant challenge beam training (BT)/beam alignment (BA), process that is required establish reliable link between...

Unmanned Aerial Vehicles (UAVs) have the advantages of high mobility and flexibility that can be potentially used as aerial base stations (BSs) to provide millimeter-wave (mmWave) communication with ground users. However, UAV mmWave beamforming must carefully designed directional transmission support reliable connections. In this paper, we consider a system, where serves BS cover mobile users on ground. Firstly, study beam training propose codebook designs for both insufficient sufficient...

Magnetic Induction (MI) based transmissions, where the typical applications are wireless power transfer (WPT) and MI communications, have gained substantial attention in recent years. Existing works related to transmissions mainly focus on case with single resonant frequency. However, from perspective of practical applications, it is highly demanded achieve multi-frequency access for transmissions. Although multiple coils can be used generate additional frequencies, each coil often one In...

Abstract Multiphase-flow oscillating heat transfer is a kind of highly efficient method. In this article, two turbulence models are used to simulate the process. Results include qualitative and quantitative comparisons with experimental data. We find that, in both closed cavity an open oil cooling gallery, SST k–ω model performs better simulation movement, as well effect prediction. The error coefficient begins increase at increasing Reynolds number, illustrating that has higher accuracy low...

Millimeter-wave (mmWave) communication has the advantage of providing large bandwidth and high throughput. Unmanned Aerial Vehicle (UAV) merit in coverage flexibility, which can compensate propagation loss mmWave communication. In this paper, we study beam training tracking for UAV We consider as aerial base stations equipped with multiple antennas serving mobile users on ground. firstly trade-off between quality cost order to maximize efficiency. Then, propose an efficient motion driven...

This paper studies the optimization of pilot training signals in Massive MIMO systems with insufficient length. We aim at finding optimal design and length that maximize Spectral Efficiency (SE) system. To achieve that, we firstly derive an approximation average achievable capacity, which is related to channel estimation error signals. Then some analysis discussions on non-orthogonal are presented order sum SE. Since previous research mainly focus orthogonal pilots, this give a criterion...

The next generation multiple access (NGMA) schemes are considered to support massive for a large number of devices, which motivates us develop low-complexity approach systems. Since the generalized spatial modulation (SM) can be adopted system, compressive sensing (CS) reconstruction algorithms deployed detection sparse signals, while complexity CS-based approaches is proportional antennas. In order decrease complexity, we propose two-stage detect where received signals divided into groups....

Intelligent reflecting surface (IRS) can be utilized to assist the millimeter-wave (mmWave) communication. In this paper, we consider an indoor IRS aided mmWave communication scenario, where base station (BS) is located close and user equipment (UE). Different with conventional system that signal transmits over a few hundred meters, only has range of several meters. Therefore, channel cannot approximated by far-field planar model. Moreover, hard focus on exact UE position due localization...

In the modern power grid, dynamic rating technology of transmission line has been drawing more and attention. Through on-line monitoring devices installed on lines, conductor temperature, environment wire current sunshine intensity are monitored in real-time, which provides solid theoretical basis raising short-term capacity developing system can effectively safely raise to satisfy demands for supply under emergency. By analysis principle, structure, functions system. The risk aversion...

Millimeter-wave (mmWave) communication utilizes very large bandwidth to provide high throughput. Unmanned Aerial Vehicle (UAV) can serve as a base station with mobility and flexibility extend the coverage. In this paper, we study UAV mmWave systems focus on beam training for communication. We formulate spectral efficiency maximization problem obtain both optimal codebook size pattern. also propose design based user distribution, which be obtained empirically. Simulation results show that...

By the help of on-line monitoring devices installed on transmission lines, conductor temperature, environment wire current and sunshine intensity are monitored in real-time. Developing dynamic rating system can effectively safely raise short-term capacity lines to satisfy demands for power supply under emergency state grid. In this paper, by analysis principle, structure, functions line system, risk aversion strategy derived based simulated research field test data improve ampacity lines....

Reconfigurable intelligent surface (RIS) is a powerful tool in assisting large-scale tera-hertz (THz) communication, especially when the line-of-sight (LoS) propagation link blocked. However, base station (BS) antenna array and RIS panel are very large, THz channel shifts from well-known far-field model to less-investigated near-field model. Conventional based training mismatches with characteristics, which leads significant performance loss. In this letter, we investigate near-filed for an...

The active sonar responder can provide coordinate target for the development, test and acceptance of sonar. paper analyzes characteristics typical signal briefly. Then is designed. hardware design software are enlarged on. Finally verified in an anechoic tank. results indicate that echoed generated by designed simulate strength, distance speed accurately.

Owing to the merit of mobility and dynamic deployment, unmanned aerial vehicle (UAV) can be widely used as users, base stations (BS) or even relays for various tasks such surveillance, photography remote sensing. Moreover, millimeter-wave (mmWave) communication with large spectrum resource meet vast demand data transmission UAV application scenarios. In this paper, considering mmWave-UAV system, we study low-overhead beam alignment enable reliable link between ground BS. We focus on uplink...

Detailed accident analysis of a tower failure in Henan was got this paper.A strain test system established, location measuring point determined at the same time.Long-term monitoring value 3# experimental base transmission line electric power accomplished.Analysis data under wind-induced vibration lays foundation for preventing damage wind and disaster system.

Developing dynamic rating system can raise short- term transmission capacity of lines effectively and safely to satisfy the demands for power supply under emergency. The model based on thermal circuit is derived through foundation steady state transient circuit. overhead line temperature at any time obtained first-order model. field test data analyzed. effectiveness proposed verified by simulation test.

Abstract Purpose A sedentary lifestyle has been an increasing public health issue especially since the outbreak of COVID-19. Limited evidence was reported on association between and prevalence thyroid nodules, a benign but prevalent concern in modern society. Methods This study used annual examination data Guangzhou officials 2020. Thyroid nodules were diagnosed following standard criteria. Sedentary self-reported as spending < 2 h, ~ 4 6 or > h per day staying sedentary. Multivariate...