Advance of Study on Design Methods of Hydraulic System of Radio Remote Control of Construction Machinery

The working principle of radio remote controlling of construction machinery should be that signals of the radio wave from the transmitter obtained in the receiver were controlled and then changed into electronic analog or digital signals which can be used to drive different actuators and mechanisms of the vehicle.The vehicle could be acted by following the controlling instructions sent by the operator.The best operation mode of construction machinery is suitable not only to manual operating but also to remote controlling in the same vehicle.The design methods of the hydraulic system used for the radio remote controlling of construction machinery are discussed.The design methods of hydraulic circuits for the actuators controlled by solenoid on-off type valves,hydro-electronic multi-way proportional valves,closed loop proportional servo driver or three-way proportional reducing valves are discussed in detail (with real example).The design methods of the power shift transmission of electro-hydraulic controlling,the devices of braking and the directional streering are discussed in this paper.

Improved spectrum sharing algorithm based on feedback control information in cognitive radio networks

In order to avoid the system performance deterioration caused by the wireless fading channel and imperfect channel estimation in cognitive radio networks, the spectrum sharing problem with the consideration of feedback control information from the primary user is analyzed. An improved spectrum sharing algorithm based on the combination of the feedback control information and the optimization algorithm is proposed. The relaxation method is used to achieve the approximate spectrum sharing model, and the spectrum sharing strategy that satisfies the individual outage probability constraints can be obtained iteratively with the observed outage probability. Simulation results show that the proposed spectrum sharing algorithm can achieve the spectrum sharing strategy that satisfies the outage probability constraints and reduce the average outage probability without causing maximum transmission rate reduction of the secondary user.

RESEARCH ON TECHNOLOGY OF CONTROLLED SOURCE RADIO MAGNETOTELLURIC SYSTEM'S TRANSMITTER

The basic theory and principle of the artificial Controlled Source Radio Magneto Telluric(CSRMT) method is studied and a novel CSRMT transmitter in kH z frequency band is designed. The specific circuit and measured results of some key modules in transmitter are presented, and some outdoor experimental tests have been carried out, which shows that the completed prototype of transmitter can generate a continuous sine current with frequency up to 35.33 k Hz, peak-to-peak amplitude up to 40 A, and realize a reliable transmitting mode with multi-frequency and high-current. The transmitter has a wide operating band, large magnetic moment and high waveform fidelity, and can meet the requirements of shallow geological exploration with high-resolution.

SPECTRUM HANDOFF IN COGNITIVE RADIO WITH FUZZY LOGIC CONTROL

The secondary usage of spectrum has been investigated in Cognitive Radio(CR) network to resolving the spectrum scarcity issue in wireless communication.When Primary Users(PU) who own the spectrum appear,spectrum handoff is needed to maintain the communications of Secondary Users.But the decision making of spectrum handoff is a challenge issue for CR network,because the input of decision making,which obtain through spectrum sensing,is heterogeneous and inexact.In this paper we will use fuzzy logic control theory to solve this issue and make use of new information for handoff operation:the probability of PU's occupancy at a certain channel.Our new algorithm can make more intelligent decision compared to simple traditional spectrum handoff decision making and reduce the probability of spectrum handoff,also the performance of SU's communication can be enhanced.

Effect of Transmission Control Protocol on Limited Buffer Cognitive Radio Relay Node

Transmission Control Protocol (TCP) is the most important transport layer protocol being used nowadays. It suffers from many problems over mobile networks especially over Cognitive Radio (CR). CR is one of the latest mobile technologies that brings its own share of problems for TCP. The buffer overflow for CR secondary network relay node can affect the performance of TCP. The contribution of this paper is the novel cross-layer model being used to evaluate the effect of the TCP congestion control on the secondary relay node buffer size in Cognitive Radio Network (CRN). The performance has been assessed by buffer overflow probability.

Intrusion Detection System with Remote Signalling for Vehicles Using an Arduino Controller and Radio-Frequency Technology

Malicious activities or policy violations have been a concern for the past years. For example, many people have been victims of robbery on vehicles. A conceptual diagram of an Intrusion Detection System (IDS) [1] [2] for vehicles with remote signaling using an Arduino controller and radio-frequency technology is proposed in this paper. To address malicious activities on vehicles, two aspects are considered here, namely: notifier and detector. Firstly, an object-oriented C module that puts on and off a controller (installed inside the vehicle) and an anti-theft electronic editing that powered using an alternator and supported by a back-up battery are implemented. Secondly, a magnetic intrusion sensor, controlled by a proximity detector using radio-frequency technology, has been installed on each vehicle door. To enable IDS, a user needs to activate the monitoring system when leaving their vehicle. This is done using a remote system. In case the user does not activate the monitoring system while leaving the vehicle, a 5-meter-proximity detector will automatically lock the system and set off the monitoring system whenever the user is outside the detection zone. The detection zone is a 5-meter radius area centered at the controller. Here, monitoring consists of geolocating any intruders within the detection zone. This means, if any of the vehicle doors is opened while the system is still locked, the controller will activate the vehicle alarm for a few seconds, thereafter send an SMS notification to the owner. The system automatically unlocks as soon as the proximity detector is within the detection zone. The contribution of this paper, as compared to other similar work, is to reinforce the electronic implementation of IDS.

Terminal-Modality-Based Joint Call Admission Control Algorithm for Fair Radio Resource Allocation in Heterogeneous Cellular Networks

There is a problem of unfairness in allocation of radio resources among heterogeneous mobile terminals in heterogeneous wireless networks. Low-capability mobile terminals (such as single-mode terminals) suffer high call blocking probability whereas high-capability mobile terminals (such as quad-mode terminals) experience very low call blocking probability, in the same heterogeneous wireless network. This paper proposes a Terminal-Modality-Based Joint Call Admission Control (TJCAC) algorithm to reduce this problem of unfairness. The proposed TJCAC algorithm makes call admission decisions based on mobile terminal modality (capability), network load, and radio access technology (RAT) terminal support index. The objectives of the proposed TJCAC algorithm are to reduce call blocking/dropping probability, and ensure fairness in allocation of radio resources among heterogeneous mobile terminals in heterogeneous networks. An analytical model is developed to evaluate the performance of the proposed TJCAC scheme in terms of call blocking/dropping probability in a heterogeneous wireless network. The performance of the proposed TJCAC algorithm is compared with that of other JCAC algorithms. Results show that the proposed algorithm reduces call blocking/dropping probability in the networks, and ensure fairness in allocation of radio resources among heterogeneous terminals.

基于边缘计算的可重构波束控制技术研究

随着社会和技术的发展,相控阵软件无线电技术得到了快速推广和普及,其应用领域从传统的军事预警探测逐步拓展到气象探测、航空安全、无人驾驶、空间探测、天地通信中继等等。同时,新方法新体制应用对天线波束形成算法复杂度、数据传输量和波束切换的低延时等提出了更高的要求,商业应用要求高效低成本部署,并能够基于软件定义具备良好的可扩展性,传统集中式波束控制方法已无法有效应对需求。波束控制节点部署利用边缘计算理念可实现相控阵天线射频前端的就近波束形成运算与数据处理,有效减小数据传输带宽和降低延时,波束控制平台采用软件可重构体制可适应新兴领域和用户需求的不断发展变化。介绍了相控阵射频前端波束控制原理,提出了一种基于边缘计算的可重构波束控制技术,采用嵌入式分布化运算处理技术,通过建模仿真与计算,证明该技术可有效改善相控阵天线多通道数据传输压力,提升波束敏捷性,实现功能、孔径可重构,具有广泛的工程应用前景。

Aerodynamic actuation characteristics of radio-frequency discharge plasma and control of supersonic flow

In this paper, aerodynamic actuation characteristics of radio-frequency(RF) discharge plasma are studied and a method is proposed for shock wave control based on RF discharge. Under the static condition, a RF diffuse glow discharge can be observed; under the supersonic inflow, the plasma is blown downstream but remains continuous and stable.Time-resolved schlieren is used for flow field visualization. It is found that RF discharge not only leads to continuous energy deposition on the electrode surface but also induces a compression wave. Under the supersonic inflow condition, a weak oblique shock wave is induced by discharge. Experimental results of the shock wave control indicate that the applied actuation can disperse the bottom structure of the ramp-induced oblique shock wave, which is also observed in the extracted shock wave structure after image processing. More importantly, this control effect can be maintained steadily due to the continuous high-frequency(MHz) discharge. Finally, correlations for schlieren images and numerical simulations are employed to further explore the flow control mechanism. It is observed that the vortex in the boundary layer increases after the application of actuation, meaning that the boundary layer in the downstream of the actuation position is thickened. This is equivalent to covering a layer of low-density smooth wall around the compression corner and on the ramp surface, thereby weakening the compressibility at the compression corner. Our results demonstrate the ability of RF plasma aerodynamic actuation to control the supersonic airflow.

机载有源相控阵火控雷达技术发展

机载火控雷达是战斗机平台获取信息的主要传感器,经历了测距机、脉冲雷达、脉冲多普勒雷达、相控阵雷达的发展历程。文中通过对现有战斗机火控雷达现状分析,结合未来战斗机平台作战需求分析等多个角度分析对机载火控雷达的需求和技术牵引,结合射频一体化、分布式探测、智能蒙皮、隐身探测和芯片化等新兴技术,展望未来机载火控雷达发展趋势,为后续机载火控雷达设计与研究提供参考借鉴。

基于哈希接入的跨网络负载均衡

无线接入网复杂化持续加剧,无线设备数量激增.为了提升未来网络容量和资源利用率,需要设计有效的拥塞控制手段和资源调配策略,平衡子网络之间负载,促进跨域资源协同共享.为此,本文在新近提出的哈希接入协议的基础上,设计了哈希接入动态优化策略,根据网络负载状况动态调整接入参数以缓解网络拥塞,并在跨网络场景下进一步提出了负载均衡方案与资源整合再调配方案,为无线接入网整合无线资源、均衡网络负载提供了有用的方法.仿真结果表明,本文提出的哈希接入动态优化策略在保证网络稳定的同时最大化网络吞吐量,资源调配方案能有效地调配失衡的网络负载,提升复杂融合网络性能和接入公平性.

微波开关自动测试系统设计

针对当前微波开关指标测试流程复杂、测试方法自动化程度低问题,提出了一套集指标测试、数据采集和数据管理功能于一体的自动化测试系统;该系统基于微波开关生产及试验环节的实际使用需求,通过软件平台实现对通用测量仪器及遥控遥测设备、射频开关矩阵等设备的自动化控制,单次可满足最多16个微波开关的同步测试,可实现同轴型和波导型两类开关的S参数、切换时间、门限电压、接触电阻、跑荷等总计18种指标参数的测试和试验数据管理,达到了测试效率和试验质量的双提升。

大口径射电望远镜伺服时滞因素分析及其预测补偿控制

射电望远镜控制系统是一个多变量复杂系统,伺服系统中的摩擦、齿轮间隙等众多时滞因素严重影响着射电望远镜系统的精度和稳定性。文中针对大口径射电望远镜伺服控制系统中的时滞因素进行研究。以模型预测控制(Model Predictive Control,MPC)为主控器,利用模糊比例-积分(Proportional-Integral,PI)控制结合Smith预估器解决时滞因素带来的影响,并利用所提出的控制方法对射电望远镜的位置控制系统进行时域分析。研究结果表明,在时滞因素影响下,大口径射电望远镜伺服控制系统依旧可以保持稳定,超调量为0.6%,稳态误差小于0.15%,满足大口径天线1.39%的指向精度要求。

儿童非囊肿型先天性梨状窝瘘的诊断及内镜微创治疗效果

目的探讨儿童非囊肿型先天性梨状窝瘘(CPSF)的诊断和内镜下微创手术治疗效果。方法回顾性分析2017年10月-2022年5月该院收治的76例非囊肿型CPSF患儿的临床资料,行喉镜、颈部彩超、食道钡餐、颈部CT和磁共振成像(MRI)检查,于全身麻醉支撑喉镜引导下,行低温等离子射频消融术。结果喉镜下可见梨状窝处内瘘口,影像学检查可见瘘管与咽部相通;术后发生暂时性声者嘶哑3例,乳牙脱落3例;术后随访12~40个月,46例初治患儿复发1例,30例非初治患儿复发1例,再次行内镜下低温等离子烧灼,术后随访均无复发。结论CPSF症状无特异性,内镜下发现内瘘口是诊断的金标准,超声可作为初筛手段,食道钡餐联合CT检查可提高诊断率,MRI可作为辅助诊断;支撑喉镜下低温等离子射频消融术具有安全、微创、美观、便捷和可重复操作等优点,可作为儿童非囊肿型CPSF治疗的首选方法。

CSRMT正交水平发射源电磁场分布规律研究

可控源射频大地电磁法(controlled source radio-magnetotellurics, CSRMT)测量通常使用发送频率1~1 000 kHz的人工场源,正交水平电偶源和正交水平磁偶源是人工源电磁法众多发射源中实现张量电阻率测量的优质场源。为此,本文基于水平电偶极子源和水平磁偶极子源电磁场解析公式,计算了均匀半空间模型正交水平电偶极子源和正交水平磁偶极子源的电磁场。结果表明,发射频率大于100 kHz时,应考虑位移电流;而张量视电阻率和阻抗相位在远区可以忽略位移电流的影响;固定模型电阻率、改变收发距时,模型计算表明高频电磁场远区测量范围更大;固定收发距、改变模型电阻率时,模型计算表明电磁场远区范围受电阻率影响较大,高阻模型需要更高的频率才会出现远区观测条件。磁偶源相较于电偶源,在张量视电阻率和相位上与实际值的偏差更小,更适于地质分析。

智慧矿山系统工程及关键技术研究与实践

针对智慧矿山复杂巨系统建设过程中存在的问题,提出了智慧矿山建设的总体技术架构,并分别从智慧矿山系统模型构建、地下空间重构与模型动态更新、机器视觉测量技术、瓦斯环境射频防爆测试方法、矿山安全闭环管控体系、智慧矿山标准体系等方面进行了详细阐述。将智慧矿山分为信息感知支撑层、边缘计算层、云数据中心、多型网络、矿山智能生产管控平台、矿山智能生产系统、智慧矿山运维管理系统,构建了基于多系统深度融合的智慧矿山技术架构。基于智慧矿山知识图谱及信息抽取技术,构建了以数据创新为驱动、通信网络为基础、数据算力为核心的智慧矿山系统模型。构建了以机器视觉感知信息为主、其他感知信息为辅的矿山井下三维视觉空间模型,提出了矿山井下场景三维视觉与空间重建框架,实现了矿山井下三维空间重构与动态更新。开发了基于机器视觉技术的井下设备位姿与煤岩界面识别算法,实现了对井下综采装备群及煤岩分界面的同时空测量。探讨了井下瓦斯环境下现行防爆标准对5G基站功率的限制及存在的不足,设计开发了射频电磁能防爆专用试验装置,为提升井下5G基站功率阈值提供了方法借鉴。提出了融合灾害信息全面感知、防控方案自主决策、防控装备协同控制的矿井灾害闭环管控系统技术架构,实现井下灾害的超前预测预警与协同防控。构建了智能化煤矿标准体系框架,剖析了我国煤矿与金属矿山智能化建设典型案例,提出了智慧矿山建设发展趋势及建议。

基于自适应跟踪的变电站远程遥控分合闸装置研制

随着电力系统自动化设备的升级改造日趋完善,变电站已能实现各类设备的远方操作,但因设备故障、控制回路断线、通信中断等原因导致远方遥控失败的情况偶发。针对变电站传统“无压无流”故障点隔离方式的陪停面积大、停电时间长的问题,研制了一种便携式多工况紧急遥控分合闸装置。该装置采用433 MHz射频无线电控制技术、可伸缩连杆以及多角度底座,实现了变电站的各类设备、多种角度的分合闸操作。结果表明,该装置可有效对变电站不同间隔进行分合闸操作,操作成功率达到98%以上,具有一定的实用性。

Multi-radio无线网络中基于协议冲突模型的功率分配算法研究

为了提高无线Ad hoc网络中的Multi-radio Multi-channel利用率,最大化全网吞吐量,提出了一种基于协议冲突模型的功率分配算法-LPCA。LPCA首先利用整数线性规划方法得到了最小功率下所有链路并行传送数据所需的最小信道数,然后又分别估计了相同功率和混合功率下Multi-radio Multi-channel网络的吞吐量上界。实验结果表明,LPCA算法能较好的利用多信道资源,有效地提高网络的吞吐量等性能。

低温等离子射频消融术治疗小儿鼾症的效果观察

目的分析低温等离子射频消融术(TCAR)治疗小儿鼾症的临床价值。方法选取2021年1月-2022年12月该院收治的120例小儿鼾症作为观察对象,采取随机数表法分为对照组(n=60,接受鼻内镜下扁桃体摘除+腺样体切除治疗)和观察组(n=60,采用鼻内镜下TCAR切除患者腺样体和扁桃体),比较两组患儿临床疗效、手术相关情况和睡眠质量。结果观察组有效率为93.33%,明显高于对照组的76.67%,差异有统计学意义(P<0.05);观察组术中出血量少于对照组,手术时间、症状缓解时间和住院时间短于对照组,VAS低于对照组,差异均有统计学意义(P<0.05);术前,两组患儿魁北克睡眠问卷(QSQ)评分、艾普沃斯嗜睡量表(ESS)和儿童阻塞性睡眠呼吸暂停低通气综合征疾病特异性生活质量调查(OSA-18)量表评分比较,差异均无统计学意义(P>0.05);术后,观察组ESS和OSA-18量表评分低于对照组,QSQ评分高于对照组,差异均有统计学意义(P<0.05);术后,两组患儿QSQ评分高于术前,ESS和OSA-18量表评分低于术前,差异均有统计学意义(P<0.05);观察组术后并发症发生率为1.67%,明显低于对照组的11.67%,差异有统计学意义(P<0.05)。结论采用鼻内镜下TCAR切除扁桃体和腺样体治疗小儿鼾症,相比于传统术式,有利于提高临床疗效,可进一步改善患儿通气功能,减轻患儿痛苦,缩短症状缓解时间,改善患儿睡眠质量和生活水平,减少术后并发症发生风险。

L波段全国产化2.5 kW级脉冲模块设计

随着国防和民用技术的迅速发展,高性能的L波段脉冲模块成为雷达和通信领域的关键组件。文章介绍了一个全国产化的2.5 kW级L波段脉冲模块的设计流程。该模块采用先进的射频放大技术和脉冲形成网络设计,结合本土材料和工艺技术的优势,实现模块的高性能和低成本生产。仿真和实验验证表明,设计的模块满足了所有预期的技术参数,包括功率水平、脉冲宽度和效率,通过了严格的质量控制和可靠性评估。