Covert communication can hide the legitimate transmission from unauthorized eavesdropping. Benefiting deployment flexibility, unmanned aerial vehicles (UAVs) be utilized to enhance confidentiality. In this correspondence, we consider a covert network with aid of full-duplex UAV relay, which is employed help and confuse warden. The warden adopts radiometer detect transmission. We first find optimal detection threshold calculate minimum error probability. Furthermore, closed-form expression...

This paper investigates quality of service (QoS) provisioning for Internet Things (IoT) in long-term evolution advanced (LTE-A) heterogeneous networks (HetNets) with partial spectrum usage (PSU). In HetNets, the IoT users ubiquitous mobility support or low-rate services requirement can connect macrocells (MCells), while femtocells (FCells) PSU mechanism be deployed to serve requiring high-data-rate transmissions within small coverage. Despite great potentials HetNets supporting various...

Vehicular ad hoc networks (VANETs) rely on intervehicle relay to extend the communication range of individual vehicles for message transmissions roadside units (RSUs). With presence a large number quickly moving in network, end-to-end transmission performance from RSUs through relaying is, however, highly unreliable due violative connectivity. As an effort toward this issue, paper develops efficient routing scheme that can maximize delivery throughput RSUs. Specifically, we first develop...

Unmanned aerial vehicle (UAV) can be combined with non-orthogonal multiple access (NOMA) to achieve better performance. However, jointly optimizing the location, transmit power and decoding order for NOMA-UAV networks remains difficult, due change of as a result UAV mobility. In this letter, low-complexity scheme is proposed maximize sum rate via updating order, which decomposed into two steps. First, joint location optimization divided non-convex sub-problems, are further approximated...

Polymeric carbon nitride (CN) is a promising photocatalyst in H2O2 photosynthesis due to its low cost and high 2e– oxygen reduction reaction (ORR) selectivity. However, the yield still unsatisfactory limited light absorption carrier recombination rate. Herein, an S-scheme heterojunction consisting of Mo-doped WO3 nanowires In-doped CN nanosheets (Mo-WO3/In-CN) was constructed. The exhibits remarkably enhanced photocatalytic performance with production rate 3082.9 μmol g–1 h–1, which 33.4 8.6...

In this paper, we analyze the user accommodation capabilities of LTE-A systems with carrier aggregation for LTE users and users, respectively. The adopted performance metric is equivalent capacity (EC), defined as maximum number allowed in system given QoS requirements. Specifically, both are divided into heterogeneous classes different requirements, traffic characteristics bandwidth weights. Two allocation strategies studied, i.e., fixed-weight strategy cognitive-weight strategy, where...

Polymeric carbon nitride (PCN)-based materials have gained increasing attention as visible-light-responsive photocatalysts for solar energy conversion, but their limited light absorption ability and low photocatalytic performance are far from satisfactory. Herein, we reported a hierarchical CdS quantum dot/polymeric nanosheet heterojunction notably enhanced CO2 conversion under visible light. Through solvothermal process, the dots were uniformly distributed tightly anchored over surface of...

Aiming to address the safety issue for uncontrolled intersection, existing schemes including design optimization of intersection structure and additional traffic signal layout will waste lots resources. With rapid development intelligent transportation, technology vehicle-vehicle communication provides a new way this problem. The paper proposed set rules clarify sequence vehicles pass through intersection. are planned based on law road safety. According rules, each approaching car makes...

With the advances of green energy technologies, clean and sustainable sources have been considered as alternative for powering cellular networks. However, it is very challenging to exploit charged satisfy QoS demands wireless multimedia services due dynamics in charging discharging processes. In this article, we study how efficiently utilize supply fulfill requirements a network. Specifically, network deployment power allocation small cell BSs two-tier support high-rate services. Our...

Covert communication has attracted growing interests as a new security technique, which focuses on concealing the signal transmission. Owing to high flexibility, unmanned aerial vehicles (UAVs) can be utilized realize long-distance covert In this correspondence, we propose UAV relaying scheme assist between two terrestrial nodes. Due risk of eavesdropping in line-of-sight (LoS) channels, assume that adopts Gaussian signalling confuse warden's detection. First, divide transmission into...

Non-orthogonal multiple access (NOMA) has been considered as a promising solution for improving the spectrum efficiency of next-generation wireless networks. In this paper, performance p-persistent slotted ALOHA system in support NOMA transmissions is investigated. Specifically, users can choose to use high or low power data with certain probabilities. To achieve maximum network throughput, an analytical framework developed analyze successful transmission probability and long term average...

The rapid development of the Chinese economy has led to an increasing fraction agricultural land being converted nonagricultural uses. zoning and protection farmland with best quality (basic farmland) is extremely intensive complicated work. In this paper we establish a remote sensing, geographic information system, particle swarm optimisation (PSO) multiobjective decision model (MODM) calculate optimum solution for basic protection. Furthermore, new evolution rule combined genetic algorithm...

This article proposes a scheme to design broadband low-profile monopulse comparator for the dual-circularly polarized feeder. For obtaining compact and easily integrated structure, with ring-shaped symmetrical planner topology is proposed by using 3 dB coupler phase shifter based on groove gap waveguide (GGW). Then, in order achieve equal-amplitude distribution broad bandwidth, asymmetrical coupling structure novel dispersion-matched transition are improve directivity of coupler. Moreover,...

The utilization of wind energy can alleviate the problems fossil shortage and environmental pollution. As core unit power generation systems, improving design manufacturing technology permanent magnet synchronous generator has become research focus researchers. In this paper, key direct drive turbine, especially semi-direct turbine with primary gear is studied, a 1.5 MW designed. To improve factor generator, reactive compensation device filter circuit are added to control circuit. results...

This work presents a piezoelectric energy harvester with clamped-clamped beams, and it is fabricated MEMS process. When excited by sinusoidal vibration, the has sharp jumping down phenomenon measured frequency responses of beams structure show larger bandwidth which about 56Hz, more efficient than that cantilever beams. exciting acceleration ac 12m/s2, achieves to maximum open-circuit voltage 94mV on one beam. The load proportional resistance, increased increase resistance. Connected four in...

The controlled switching technology of a short circuit current has been proposed for long time. However, the opening time mechanism used in high voltage breaker is normally tens milliseconds and variation milliseconds. electromagnetic repulsion very limited It provides potential achieving breaker. objective this paper to design 126 kV double-break fast vacuum switching. driven by mechanism. consist two units. Each one interrupter an individually. units are connected series withstand applied...

Complex wastewater with massive components is now a serious environmental issue facing humanity. Selective removal of low-concentration contaminants in mixed constituents holds great promise for increasing water supplies. Bioenzymes like horseradish peroxidase exhibit oxidizing power and selectivity. Here, we manufactured its mimic through immobilizing non-heme oxamate anionic cobalt(III) complex ([CoIII(opba)]-, opba = o-phenylenebis(oxamate)) onto pyridine (Py) modified multiwalled carbon...

It has an important impact on the overall power communication network reliability to identify location of critical nodes in and further develop protection methods. On topology layer network, Node Topology Importance(NTI) is proposed based calculating rate natural connectivity after one node being destroyed; A calculation method business presented by considering requirements indexes, then taking into account layer, weighted which fuses information defined, accordingly Combining...

Vehicular communication networks hold promise to significantly improve road safety by giving both automated vehicles and human drivers improved awareness advanced warning emergencies. The emergency messages are broadcasted upon detection, but this does not guarantee recipients will be able avoid collision. In paper, we introduce a method relate the delay tolerance of each vehicle in network directly transmission range taking into consideration reaction time order ensure can system utilizes...

Based on the navigation strategy of insects utilizing polarized skylight, an integrated polarization sensor for autonomous is presented. The fabricated using proposed nanoimprint photolithography (NIPL) process by integrating a nanograting polarizer and image chip. NIPL uses UV-transparent variant template with nanoscale patterns microscale metal light-blocking layer. During process, part resist material pressed to fill into nanofeatures cured under UV exposure. At same time, other parts...