An Encode-and CRT-Based Scalability Scheme for Optimizing Transmission in Blockchain

Blockchain technology has witnessed a burgeoning integration into diverse realms of economic and societal development.Nevertheless,scalability challenges,characterized by diminished broadcast efficiency,heightened communication overhead,and escalated storage costs,have significantly constrained the broad-scale application of blockchain.This paper introduces a novel Encode-and CRT-based Scalability Scheme(ECSS),meticulously refined to enhance both block broadcasting and storage.Primarily,ECSS categorizes nodes into distinct domains,thereby reducing the network diameter and augmenting transmission efficiency.Secondly,ECSS streamlines block transmission through a compact block protocol and robust RS coding,which not only reduces the size of broadcasted blocks but also ensures transmission reliability.Finally,ECSS utilizes the Chinese remainder theorem,designating the block body as the compression target and mapping it to multiple modules to achieve efficient storage,thereby alleviating the storage burdens on nodes.To evaluate ECSS’s performance,we established an experimental platformand conducted comprehensive assessments.Empirical results demonstrate that ECSS attains superior network scalability and stability,reducing communication overhead by an impressive 72% and total storage costs by a substantial 63.6%.

Blocking Effects of Spleen Vaccine on Vertical Transmission of Classical Swine Fever Virus in Sows

[ Objective] To investigate the blocking effects of spleen vaccine on vertical transmission of classical swine fever virus （CSFV） in sows. [ Method] Sows infected by CSFV were selected from three large-scale pig farms and they were randomly divided into group Ⅰ, group Ⅱ and control group. The sows in the group Ⅰ were vaccinated with CSF spleen vaccine at a 1.5 times normal dose per pig; those in the group Ⅱ were vaccinated with CSF spleen vaccine at a 2.0 times normal dose per pig; and those in the control group were vaccinated with cell vaccine at a 4.0 times normal- dose per pig. The CSF antigens of piglets were detected by enzyme-linked immunosorbent assay （ELISA）. [ Result] The antigen positive rate of piglets in the experimental group （18.5%） was significantly lower than that in the control group （48.1% ）. No significant difference was found be- tween the group Ⅰ and the group Ⅱ. [ Condmion] CSF spleen vaccine has good blocking effects on vertical transmission of CSFV in sows.

Reflection and transmission properties of double submerged rectangular blocks

An analytic method is used to study the reflection and transmission coefficients of the double submerged rectangular blocks （DSRBs） in oblique waves. The scattering potentials are obtained by means of the eigenfunction expansion method, and expressions for the reflection and transmission coefficients are determined. The boundary element method is employed to verify the correctness of the present analytical method. The DSRBs have better performance than the single submerged rectangular block （SSRB） in certain cases. The reflection and transmission properties of the DSRBs are investigated for some specific cases, and the influences of the geometric parameters are also presented.

Spatial-Modulated Physical-Layer Network Coding Based on Block Markov Superposition Transmission for Maritime Relay Communications

As an alternative to satellite communications,multi-hop relay networks can be deployed for maritime long-distance communications.Distinct from terrestrial environment,marine radio signals are affected by many factors,e.g.,weather conditions,evaporation ducting,and ship rocking caused by waves.To ensure the data transmission reliability,the block Markov superposition transmission(BMST)codes,which are easily configurable and have predictable performance,are applied in this study.Meanwhile,the physical-layer network coding(PNC)scheme with spatial modulation(SM)is adopted to improve the spectrum utilization.For the BMST-SMPNC system,we propose an iterative algorithm,which utilizes the channel observations and the a priori information from BMST decoder,to compute the soft information corresponding to the XORed bits constructed by the relay node.The results indicate that the proposed scheme outperforms the convolutional coded SM-PNC over fast-fading Rician channels.Especially,the performance can be easily improved in high spatial correlation maritime channel by increasing the memory m.

Generalized Block Markov Superposition Transmission over Free-Space Optical Links

In free-space optical(FSO) communications, the performance of the communication systems is severely degraded by atmospheric turbulence. Channel coding and diversity techniques are commonly used to combat channel fading induced by atmospheric turbulence. In this paper, we present the generalized block Markov superposition transmission(GBMST) of repetition codes to improve time diversity. In the GBMST scheme, information sub-blocks are transmitted in the block Markov superposition manner, with possibly different transmission memories. Based on analyzing an equivalent system, a lower bound on the bit-error-rate(BER) of the proposed scheme is presented. Simulation results demonstrate that, under a wide range of turbulence conditions, the proposed scheme improves diversity gain with only a slight reduction of transmission rate. In particular, with encoding memory sequence(0, 0, 8) and transmission rate 1/3, a diversity order of eleven is achieved under moderate turbulence conditions. Numerical results also show that, the GBMST systems with appropriate settings can approach the derived lower bound, implying that full diversity is achievable.

Effects of information transmission delay and channel blocking on synchronization in scale-free Hodgkin-Huxley neuronal networks

In this paper,we investigate the evolution of spatiotemporal patterns and synchronization transitions in dependence on the information transmission delay and ion channel blocking in scale-free neuronal networks.As the underlying model of neuronal dynamics,we use the Hodgkin-Huxley equations incorporating channel blocking and intrinsic noise.It is shown that delays play a significant yet subtle role in shaping the dynamics of neuronal networks.In particular,regions of irregular and regular propagating excitatory fronts related to the synchronization transitions appear intermittently as the delay increases.Moreover,the fraction of working sodium and potassium ion channels can also have a significant impact on the spatiotemporal dynamics of neuronal networks.As the fraction of blocked sodium channels increases,the frequency of excitatory events decreases,which in turn manifests as an increase in the neuronal synchrony that,however,is dysfunctional due to the virtual absence of large-amplitude excitations.Expectedly,we also show that larger coupling strengths improve synchronization irrespective of the information transmission delay and channel blocking.The presented results are also robust against the variation of the network size,thus providing insights that could facilitate understanding of the joint impact of ion channel blocking and information transmission delay on the spatiotemporal dynamics of neuronal networks.

Closed Loop Space-Time Block Coding for Wireless Downlink Transmission

In order to improve the poor performance of Space-Time Block Coding (STBC) in a downlink correlated fading environment, a closed loop scheme is proposed. With the known channel fading statistics fed from the receiver, eigenbeamforming is utilized to improve the performance of STBC at the transmitter. The new system achieves the array and diversity gain simultaneously. Because reduced dimension processing is adopted, the proposed system has a relative simple structure compared with the traditional beamforming system. The validity of the scheme is verified in several situations by simulation experiments.

Bridging the Knowledge Gap in Transmission-Blocking Immunity to Malaria: Deciphering Molecular Mechanisms in Mosquitoes

The worldwide decline over the last decade in the number of clinical cases of malaria does not mean an end to the universal problem of malaria pathogenesis in those afflicted by infection. Resistance to drugs, higher risk of disease relapse and failure to maintain effective memory of the pathogen in the absence of persistent exposure result in the repeated failure of anti-malarialtreatments. The artificial blocking of transmission of the Plasmodium parasite between hosts from human to Anopheles mosquito, and vice versa, is crucial to restricting the spread of disease. However, a limited knowledge of the molecular mechanisms in operation for transmission of malaria has impeded progress towards a transmission-blocking vaccine. This review highlights the role of anti-malarial immune responses to antigen-specific targets for designing effective vaccines against the sexual stages of Plasmodium that occur within the invertebrate vector. In particular, artificial induction of gametocyte and ookinete apoptosis as a novel means to prevent gamete fertilization and oocyte development, respectively, is highlighted. This and other recent insights into our understanding of the molecular regulation of transmission-blocking immunity are discussed and future prospects considered.

Spatially Coupled Codes via Bidirectional Block Markov Superposition Transmission

In this paper,we present a new class of spatially coupled codes obtained by using both non-recursive and recursive block-oriented superposition.The resulting codes are termed as bidirectional block Markov superposition transmission(BiBMST)codes.Firstly,we perform an iterative decoding threshold analysis according to protograph-based extrinsic information transfer(PEXIT)charts for the BiBMST codes over the binary erasure channels(BECs).Secondly,we derive the generator and parity-check matrices of the BiBMST codes.Thirdly,extensive numerical results are presented to show the advantages of the proposed BiBMST codes.Particularly,our numerical results show that,under the constraint of an equal decoding latency,the BiBMST codes perform better than the recursive BMST(rBMST)codes.However,the simulation results show that,in finite-length regime,negligible performance gain is obtained by increasing the encoding memory.We solve this limitation by introducing partial superposition,and the resulting codes are termed as partially-connected BiBMST(PC-BiBMST)code.Analytical results have confirmed the advantages of the PC-BiBMST codes over the original BiBMST codes.We also present extensive simulation results to show the performance advantages of the PC-BiBMST codes over the spatially coupled low-density parity-check(SC-LDPC)codes,spatially coupled generalized LDPC(SC-GLDPC)codes,and the original BiBMST codes in the finite-length regime.

一种可实现双向故障闭锁的双极Y型模块化多电平直流变换器

直流电网互联通常采用隔离型高压大功率直流变换器,但其存在体积大、成本高及传输效率较低等问题。该文提出一种双极Y型模块化多电平DC/DC变换器,其避免使用中间变压器,实现直流功率双向传输,并且可以有效闭锁双向直流故障。首先分析了变换器拓扑结构及故障闭锁工作原理,并根据桥臂内电势等效原理建立了数学模型。基于变换器臂间、相间能量平衡约束,在闭环控制的基础上引入桥臂电流补偿控制,提升变换器暂态性能。最后,在Matlab/Simulink搭建了采用模块化多电平DC/DC变换器(modularmultilevelDC/DCconverter,DC-MMC)的直流输电系统仿真模型,通过对端口电流、桥臂电流及桥臂电容电压等动态指标的分析,验证了所提DC-MMC双向功率传输控制及双向故障闭锁能力的可行性和有效性。

海上风电柔性直流输电换流变差动保护的适应性分析

海上风电柔性直流输电系统的故障特性有别于常规电力系统,因此常规继电保护方案应用于海上风电柔性直流输电系统时可能存在适应性不足的风险。分析了海上风电柔性直流输电系统故障情形下,不对称的电气量引发的谐波分量以及故障穿越过程中的负序抑制、限流措施对差动保护的影响。推导了计及序分量的差动保护灵敏度计算式并进行适应性分析,指出故障情形下的奇次谐波容易对差动保护产生影响,负序抑制及限流措施也将导致差动保护灵敏度下降。结合实际示范工程的仿真系统进行了大量仿真计算,结果表明,常规差动保护方案的灵敏性、可靠性均存在下降的问题。

基于逆阻型IGCT器件的固态式直流断路器设计及研制

直流系统是支撑高比例新能源接入与灵活高效用能的重要技术方向。固态式直流断路器(solid state DC circuit breaker,SSCB)具有开断速度极快、无电弧、寿命长等优点,在中低压直流系统的故障保护中得到广泛应用。随着电力电子器件的发展,固态式直流断路器的拓扑结构、工作性能也在不断进步。为此基于逆阻型集成门极换流晶闸管(intergated gate commutate thyristor,IGCT),提出了一种新型的固态式直流断路器结构及设计方法,通流支路采用逆阻IGCT反并联结构实现双向通流,缓冲支路采用金属氧化物避雷器(metal oxide varistor,MOV)-电容结构来抑制过电压,吸能支路采用MOV吸收系统能量。进一步地,给出了关键元器件的参数设计方法,并验证了有效性;设计了性能良好的重力热管散热器,单个模块散热功率可达700 W;提出了主被动结合的控保策略,提高断路器的保护性能。最后,研制了固态式直流断路器样机,可用于750 V以内的低压直流系统,额定通流可达2 kA,可在百微秒内开断10 kA故障电流,成本低、体积小、高可靠,具有良好的应用前景。

基于改进YOLOv7的输电铁塔塔基检测算法

输电塔作为整个电力传输系统最重要的组成部分之一,需要及时对输电塔进行检测保证塔基的稳固以保障后期的使用。针对无人机采集到的输电塔图像存在背景复杂、背景与目标塔基对比度低、小目标及塔基不完整等问题,提出了基于改进YOLOv7的输电塔塔基检测算法。首先,通过无人机采集不同地形地貌的输电塔图像,构建高质量数据集。然后,在原始YOLOv7的Backbone层中加入卷积注意力模块CBAM注意力机制,以提高输电塔塔基特征的提取能力。最后,引入WIoU v3代替原坐标损失函数CIoU,以提高目标检测任务的准确性和稳定性。在该数据集上,使用改进后的YOLOv7算法与目前主流的目标检测算法进行对比实验,实验结果中所提算法的mAP值高达99.93%,比原始YOLOv7提高2.19%,FPS值为37.125,满足实时检测需求,算法的整体性能较好。实验验证了所提算法在塔基检测上的可行性和有效性,为后续塔基区周围水土情况的研究奠定了基础。

HBV高载量孕妇孕期抗病毒治疗结合标准阻断措施阻断母婴传播效果

目的:探究乙型肝炎病毒(HBV)高载量孕妇孕期HBV-DNA水平和乙型肝炎病毒e抗原(HBeAg)阳性情况,分析孕期抗病毒治疗结合标准阻断措施对HBV高载量孕妇母婴传播阻断效果。方法:回顾性收集2021年1月-2023年1月本院住院分娩的120例HBV高载量孕妇临床资料,分析孕妇妊娠期、分娩前HBV-DNA水平和HBeAg阳性率,多因素logistic回归分析HBeAg状态影响因素,分析孕期抗病毒治疗对新生儿乙肝母婴传播阻断效果及母婴安全性。结果:120例HBV高载量孕妇中,孕期接受抗病毒治疗93例(治疗组),抗病毒药物分别为替诺福韦占56.6%、拉米夫定占20.8%;未接受治疗27例(未治疗组)。妊娠期,抗病毒治疗组和未治疗组HBV-DNA载量、HBeAg阳性率无差异(P>0.05);分娩前,抗病毒治疗组HBV-DNA载量≥10^(6)IU/ml占比(7.5%)低于未治疗组(92.6%)(P<0.05),而两组HBeAg阳性率(90.3%、92.6%)无差异(P>0.05)。多因素logistic分析,年龄低、HBVDNA载量高影响HBeAg状态的独立危险因素(P<0.05)。新生儿乙肝母婴传播阻断率抗病毒治疗组(100.0%)高于未治疗组(2例,92.6%)(P<0.05)。两组新生儿体质量、早产、剖宫产、妊娠合并症、产时并发症比较无差异(P>0.05)。结论:HBV高载量孕妇HBV-DNA水平较高,HBeAg阳性率与孕妇年龄低、HBV-DNA载量高有关;孕期抗病毒治疗可降低孕妇分娩前HBV-DNA水平,结合标准阻断措施后可提高HBV母婴传播阻断率,且安全性较好。

背靠背直流输电故障闭锁后过电压分析和优化

背靠背直流输电系统某些靠近接地点端发生直流母线接地故障时,系统闭锁后会出现过电压现象。本文分析其原因为故障点与接地点形成短路回路,引起阀短路保护先于极区接地保护动作。此类故障情况下,阀短路保护动作后执行立刻闭锁,在闭锁过程中造成直流系统过电压;而单独的直流母线接地故障执行正常闭锁,或者单独的阀短路故障执行立刻闭锁,均不会出现闭锁后的过电压现象。本文引入接地点电流作为辅助判据,提出两种优化方法。当发生相同的靠近接地点端直流母线接地故障时,控制系统有选择性地执行不同闭锁方式,可有效避免闭锁后出现直流系统过电压,有利于电力系统故障的可靠隔离,降低系统一次设备运行风险。

围产期乙肝病毒母婴传播阻断的研究进展

乙型肝炎病毒(hepatitis B virus,HBV)是一种常见的全球血液传播病原体,其导致的部分慢性乙肝患者可发展为肝硬化和肝癌,甚至导致死亡[1]。据统计,全世界约有640万名五岁以下儿童患有慢性HBV感染,中国是世界上HBV感染负担最大的国家,2019年中国约2.96亿人感染HBV,每年150万新增感染,其中,围产期母婴传播是HBV传播的主要途径之一,新生儿乙肝感染的风险为95%[2]。目前,我国育龄期妇女HBsAg的阳性率为5%~6%,HBsAg阳性孕妇的新生儿是HBV感染的高危人群[3]。阻断母婴传播是预防HBV的源头,母婴阻断主要是通过一定的医疗技术手段,阻止母体HBV传播给婴幼儿的方式。研究表明,母婴阻断对于新生儿乙肝预防和人类生命健康具有重要意义[4]。本文对围产期HBV母婴传播阻断进行综述。

基于工业级4G物联网北斗配电自动化通信技术研究

针对输电过程中配电自动化通信传输量低、速度较慢的问题,本文提出了基于工业级4G物联网北斗配电自动化通信技术,引入云边协同方式和终端直通技术模块对配电自动化设备之间通信结构进行改进。首先,将其与基站构建中继通信网络来提高配电网中数据传输速度;接着,对安全设备管理器算法进行改进,通过获取各传输信道的误码率来计算信道的阻塞特征;最后,对阻塞信道进行调制处理,使传输数据更具协同特征,进一步提高传输速度。试验结果表明,通过该系统检测出通信总量最高为48 TB,传输速度平均为10 MB/s,表明本研究系统具有很好的适用性。

基于无人机机载AI模块的电力巡检技术

针对输电线路无人机巡检实时性和准确性的要求,深入研究了YOLOv3目标检测算法在无人机巡检机载AI模块中的应用。利用将目标检测候选区选取和对象识别合二为一的YOLOv3算法,结合多尺度特征融合方式实现了目标检测的高准确性和实时优化,并采用残差块解决了模型退化问题。输电线路绝缘子检测结果表明:YOLOv3算法平均精度可达90%,相同条件下YOLOv3算法平均处理速度约为Faster RCNN算法的3.2倍,约为SSD算法的1.6倍。

实验室参加量块能力验证注意事项及比对结果分析

通过能力验证活动可以客观评价实验室技术能力及管理水平,是实验室申请能力认可、扩项评审及获批项目能力建设的重要依据。本文根据实际参加量块能力验证活动工作经验,详细介绍了实验室参加量块能力验证的注意事项,并通过对我院2022年量块国家计量比对结果进行分析。结果表明,陕西省计量科学研究院的技术能力及管理水平良好,量块量值传递准确可靠。