On Differentiation Among Pilot Signals of Multiple Mobile Targets in Retro-Reflective Beamforming for Wireless Power Transmission

An experimental study is conducted on several retro-reflective beamforming schemes for wireless power transmission to multiple wireless power receivers(referred to herein as“targets”).The experimental results demonstrate that,when multiple targets broadcast continuous-wave pilot signals at respective frequencies,a retro-reflective wireless power transmitter is capable of generating multiple wireless power beams aiming at the respective targets as long as the multiple pilot signals are explicitly separated from one another by the wireless power transmitter.However,various practical complications are identified when the pilot signals of multiple targets are not appropriately differentiated from each other by the wireless power transmitter.Specifically,when multiple pilot signals are considered to be carried by the same frequency,the wireless power transmission performance becomes heavily dependent on the interaction among the pilot signals,which is highly undesirable in practice.In conclusion,it is essential for a retro-reflective wireless power transmitter to explicitly discriminate multiple targets’pilot signals among each other.

Numerical modeling of DPSK pressure signals and their transmission characteristics in mud channels

A numerical model and transmission characteristic analysis of DPSK （differential phase shift keying） pressure signals in mud channels is introduced. With the control logic analysis of the rotary valve mud telemetry, a logical control signal is built from a Gate function sequence according to the binary symbols of transmitted data and a phase-shift function is obtained by integrating the logical control signal. A mathematical model of the DPSK pressure signal is built based on principles of communications by modulating carrier phase with the phase-shift function and a numerical simulation of the pressure wave is implemented with the mathematical model by MATLAB programming. Considering drillpipe pressure and drilling fluid temperature profile along drillpipes, the drillpipe of a vertical well is divided into a number of sections. With water-based drilling fluids, the impacts of travel distance, carrier frequency, drillpipe size, and drilling fluids on the signal transmission were studied by signal transmission characteristic analysis for all the sections. Numerical calculation results indicate that the influences of the viscosity of drilling fluids and volume fraction of gas in drilling fluids on the DPSK signal transmission are more notable than the others and the signal will distort in waveform with differential attenuations of the signal frequent component.

Self-Adaptive Matching Method of Signal and Energy Transmission

Aimed at the rapid message setting of the passive systems, the efficiency of energy transmission and the characteristics of signal transmission in the message setting are analyzed, which is based on the methods of the circuit analysis and the electromagnetic induction technology. A self-adaptive impedance matching method of signal and energy transmission, which can set the message rapidly and effectively, is put forward. The electromagnetic induct setting system will reach the highest energy transmission efficiency when the equivalent resistance of the second loop is equal to the resistance of the first loop. The greater the ratio of the equivalent resistances is, the higher efficient the signal transmission has. Moreover, the validity of the method is verified by circuit design and tests.

STABILITY ANALYSIS OF BIDIRECTIONAL ASSOCIATIVE MEMORY WITH AXONAL SIGNAL TRANSMISSION DELAYS

In this paper, conditions for the existence of equilibrium points and global stability are emphatically discussed for Bidirectional Associative Memory(BAM) models with axonal signal transmission delays, and the discussed methods are more general. The correctness of obtained conclusions is verified by use of some examples. The obtained results have primary significance in the design and application of BAM.

A new viewpoint and model of neural signal generation and transmission: Signal transmission on myelinated neuron

Based on our previous work, we study the problem of neural signal transmission of myelinated neurons. We found that the transmembrane ion current at Ranvier's node acts as an energy supplement. In addition, the length of the myelin sheath has an upper limit of lT. Above this upper limit, the neural signal will not be effectively transmitted. In the range of normal physiological parameters, lT is on the order of mm. Finally, the effect of temperature on the transmission of nerve signals is investigated. temperatures that are too high and too low are not conducive to the conduction of nerve signals.

A new method for improving the inductively coupled data transmission rate of mooring buoy based on carrier signal frequency selection

In the inductively coupled data transmission system of the mooring buoy, the carrier signal frequency of the transmission channel is limited due to the inherent characteristics of the system, resulting in limited channel bandwidth. The limited channel bandwidth limits the increase in inductively coupled data transmission rate.In order to improve the inductively coupled data transmission rate of mooring buoy as much as possible without damaging the data transmission performance, a new method was proposed in this paper. The method is proposed to improve the data transmission rate by selecting the appropriate carrier signal frequencies based on the principle of maximizing the amplitude value of amplitude-frequency characteristic curve of the system. Research has been done according to this method as follows. Firstly, according to the inductively coupled transmission mooring buoy structure, the inductively coupled data transmission circuit model was established. The binary frequency shift keying(2FSK) digital signal modulation mode was selected. Through theoretical analysis, the relation between the carrier signal frequency and the data transmission performance, the relation between the carrier signal frequency and the 2FSK signal bandwidth were obtained. Secondly, the performance and the bandwidth of the signal transmission were studied for the inherent characteristics of the actual inductively coupled data transmission system. The amplitude-frequency characteristic of the system was analyzed by experiments. By selecting the appropriate carrier signal frequency parameters, an excellent data transmission performance was guaranteed and a large 2FSK signal bandwidth was obtained. Finally, an inductively coupled data transmission rate optimization experiment and a bit error rate analysis experiment were designed and carried out. The results show that the high-speed and reliable data transmission of the system was realized and the rate can reach 100 kbps.

Cell transmission model based traffic signal timing in oversaturated conditions

In order to investigate enhancements to cell transmission model (CTM) as a tool for traffic signal timing in oversaturated conditions, randomly distributed saturation flow rates and arrival rates were used instead of constant values to simulate traffic flow movement, estimate the average delay of the network and search for an optimal traffic signal timing plan. A case study was given to demonstrate that the proposed methodology can capture unique phenomena in oversaturated conditions such as forward wave, spillback and lane entrance blockage. The results show that CTM underestimates travel time by 25% when compared to Simtraffic, while the enhanced CTM underestimates by only 3%. A second case study shows that a dynamic signal timing plan is superior to a fixed signal timing plan in the term of average delay.

Fragmental Weight-Conservation Combining Scheme for Statistical Signal Transmissions under Fast Time-Varying Channels

Statistical Signal Transmission(SST)is a technique based on orthogonal frequency-division multiplexing(OFDM)and adopts cyclostationary features,which can transmit extra information without additional bandwidth.However,the more complicated environment in 5G communication systems,especially the fast time-varying scenarios,will dramatically degrade the performance of the SST.In this paper,we propose a fragmental weight-conservation combining(FWCC)scheme for SST,to overcome its performance degradation under fast time-varying channels.The proposed FWCC scheme consists of three phases:1、incise the received OFDM stream into pieces;2、endue different weights for fine and contaminated pieces,respectively;3、combine cyclic autocorrelation function energies of all the pieces;and 4、compute the final feature and demodulate data of SST.Through these procedures above,the detection accuracy of SST will be theoretically refined under fast time-varying channels.Such an inference is confirmed through numerical results in this paper.It is demonstrated that the BER performance of proposed scheme outperforms that of the original scheme both in ideal channel estimation conditions and in imperfect channel estimation conditions.In addition,we also find the experiential optimal weight distribution strategy for the proposed FWCC scheme,which facilitates practical applications.

Analysis of Optical Signal Transmission Characteristics in AWG Multi/Demultiplexer with Electromagnetic Field Theory

Based on the electromagnetic field theory, the optical signal transmission characteristics in input/output waveguides, slab waveguides and arrayed waveguides of the arrayed waveguide grating (AWG) multi/demultiplexer are analyzed. The relationship between the physical parameters such as geometry sizes and relative refractive index in AWG multi/demultiplexer and the optical signal transmission characteristics are discussed. This theoretical study can be used for optimizing the design and improving the performance of the AWG multi/demultiplexer.

EFFICIENT IMAGE TRANSMISSION SCHEME IN FMT SYSTEM

An efficient image transmission scheme is proposed based on byte partition and adaptive sub-channel distribution technique in Filtered MultiTone (FMT) system over frequency selective slow fading channel. According to the simulation results and analysis of a typical image with matlab, improvement in Peak Signal to Noise Ratio (PSNR) of the received image and low complexity for equalization is demonstrated remarkably. Comparing with no adaptive and no actual channel equalization scheme, the proposed scheme saves over 6 dB when PSNR=40 dB.

Retro-reflective Beamforming Technique with Applications in Wireless Power Transmission

Retro reflective beamforming technique has the potential of enabling efficient wireless power transmission over long distance(on the order of meters and even kilometers).In retro reflective beamforming,wireless power transmission is guided by pilot signal:Based upon pilot signal broadcasted by a wireless power receiver,a wireless power transmitter delivers focused microwave power beam(s)onto the location of wireless power receiver.When the wireless power receiver’s location is not fixed or when the wireless power receiver’s location is unknown to the wireless power transmitter,the microwave power beam would follow the wireless power receiver’s location dynamically as long as the wireless power receiver broadcasts pilot signal periodically.This paper reviews our research endeavors in recent years on retro reflective beamforming technique targeting three applications:(1)wireless charging for low power mobile/portable electronic devices,(2)space solar power satellites(SSPS)application,and(3)wireless charging in fully enclosed space.The feasibility and potential of retro reflective beamforming technique with applications in wireless power transmission are demonstrated by some preliminary experimental results.

A Stream Control Transmission Protocol Based OAM System of 3G Cellular Network

OAM (Operations, Administration and Maintenance) system is a very impo rtant component of 3G cellular network. In order to acquire overall managemen t, fast response and steady operation, an SCTP (Stream Control Transmission Prot ocol) based OAM, i.e., SOAM system was proposed. SOAM implements new characters of SCTP such as multi-stream, enforced SACK and heartbeat mechanism on its tran sport layer. These characters help SOAM decrease the message transmission delay and accelerate the link failure detection. Besides, a new component named SOAM agent was introduced to improve the operation efficiency of SOAM. The experim ental results prove the proposed SOAM system achieves better performance on sign aling transmission compared with conventional TCP based OAM system.

VIDEO TRANSMISSION SYSTEM IN ITV APPLICATION

The transmission characteristics of video transmission mediums,coaxial ca ble and optical fiber,are discussed in the paper. The formulas for frequency bandwidth are given to evaluate the video transmission distance. For typical video transmission systems with BB/IM and PFM/IM tising optical fiber as the channel, expressions and calculating results for both S/N and sensitivity are given. Finally, the principle for se lecting different type of transmission systems according to transmission distances of the industrial TV is presented.

新一代地面站测控数传通用处理资源池设计

随着我国在轨卫星数量和类型的日益增多,对地面站测控数传系统的通用性、扩展性提出了更高的要求。提出了基于云计算架构、采用通用硬件基础设施搭建测控数传通用处理资源池的思路,对资源池的总体架构、硬件组成、软件实现方法、系统运行流程等关键技术进行了详细阐述;搭建了原型样机进行技术验证。基于云计算架构的新一代测控数传通用处理资源池系统能够显著提高测控数传系统的使用效率,提升航天地面测控系统的可重构能力、可扩展能力和多任务多目标的适应能力。

基于电场耦合的电能信号并行传输系统串扰抑制方法

针对较大功率电场耦合无线电能传输系统信号双向高速传输的需求,该文提出一种基于部分能量通道的电能与信号并行传输系统的串扰抑制方法。通过对所提出的系统拓扑进行分析,给出了电能传输增益表达式与电能串扰增益表达式,并分析了阻波电路参数变化对电能串扰增益的影响;基于交流阻抗法及香农定理分别给出了信号传输增益及信道容量表达式,分析了信号支路参数对信道容量的影响;在综合考虑信号传输增益、信道容量及阻波电路参数敏感性的情况下,给出系统信号支路参数的设计方法。该方法能保证系统在较大功率下降低电能串扰,保障信号稳定传输,实现信号的双向高速传输。通过仿真与实验验证了所提出的拓扑和参数设计方法的有效性。搭建的实验装置实现了传输530.4 W的电能,23.28 Mbit/s信号正向传输速度和24.2428 Mbit/s信号反向传输速度。

董事高管责任保险与碳信息披露质量

在实现国家“碳达峰、碳中和”战略目标的背景下,上市公司紧跟国家政策导向,积极履行自愿披露碳信息的义务。基于此,本文以2015~2022年中国A股上市公司为样本,实证检验了董责险对碳信息披露质量的影响。研究发现,董责险通过最大诚信原则的保险文化、保险公司的持续监督和自发传递积极的信号,提高企业的碳信息披露质量。机制上,董责险提高内部控制质量,进而影响碳信息披露质量。进一步地,当上市公司属于重点排污单位、处于非低碳试点城市、市场化程度高时,董责险对碳信息披露质量的影响更显著。本文研究为构建更完善的保险服务体系、深化绿色低碳转型的治理体系提供了理论依据,并对我国实现“双碳”战略目标具有一定的启示意义。

超额商誉与商业信用成本:基于风险和内控视角

为厘清超额商誉与商业信用成本间的关系,从供应商与企业间融资成本视角出发,以2014—2021年沪深A股公司为样本,基于信号传递理论,分析超额商誉对商业信用成本的影响机制。研究发现:超额商誉正向影响企业商业信用成本;超额商誉通过加剧企业经营风险,进而增加商业信用成本;较高的内部控制质量对超额商誉与商业信用成本间关系起负向调节作用,且随着内部控制质量的提升,超额商誉加剧经营风险的作用会有所减少,相应其对商业信用成本的正向影响也会减弱;在独立董事比例高、高管股权激励水平高和高管薪酬激励水平低的情形下,超额商誉对商业信用成本的正向影响降低,较高的独董比例和高管股权激励能一定程度缓解超额商誉的负面影响。

企业ESG表现与融资约束——基于信息披露数量与质量的再讨论

在气候变化日益受到关注的背景下,实现企业发展与资本市场的良性互动,不仅可以有效满足企业发展的资金需求,也有助于我国经济高质量发展,实现双碳目标。本文在信号传递理论模型基础上,利用2010-2019年1136家上市公司数据,从理论和实证两个方面分析了企业ESG表现对融资约束的影响及其非对称性。研究发现,企业的ESG表现能够显著降低自身的融资约束。机制分析表明,ESG表现能够降低企业与投资者之间的信息不对称,且ESG信息披露数量和质量的作用存在不同,现阶段提升企业信息披露质量的效果会优于提升信息披露数量。同时,ESG表现对企业不同融资方式具有明显的非对称影响,在抑制内部融资的同时会缓解债务融资和股权融资,企业需要权衡长期利益与短期利益之间可能的冲突。本文为政府制定企业信息披露政策、引导社会责任投资提供了有益的实证证据和决策指导。

考虑特征向量约束的低频声信号声源定位系统

低频信号在传输过程中,容易受到环境噪声的干扰,导致信号强度降低,从而影响声源定位的精度。为了提升低频声信号声源定位能力,提出一种考虑特征向量约束的低频声信号声源定位系统。通过MEMS声传感器采集低频声信号,对其进行去噪处理,并传输至低频声信号声源定位模块;采用考虑特征向量约束的低频声信号声源定位方法实现对低频声信号声源定位。实验结果表明:所提系统的低频声信号声源定位与实际位置坐标的误差小,说明该系统的定位方法性能优良,定位精度较高,能够提升低频声信号声源定位能力。