Loss of heterozygosity for chromosomes 16q in Wilms tumors predicts outcomes:A meta-analysis

BACKGROUND The research findings suggest that the prognosis of children with Wilms tumor(WT)is affected by various factors.Some scholars have indicated that loss of heterozygosity(LOH)on chromosome 16q is associated with a poor prognosis in patients with WT.AIM To further elucidate this relationship,we conducted a meta-analysis.METHODS This meta-analysis was registered in INPLASY(INPLASY2023100060).We systematically searched databases including Embase,PubMed,Web of Science,Cochrane,and Google Scholar up to May 31,2020,for randomized trials reporting any intrapartum fetal surveillance approach.The meta-analysis was performed within a frequentist framework,and the quality and network inconsistency of trials were assessed.Odds ratios and 95%CIs were calculated to report the relationship between event-free survival and 16q LOH in patients with WT.RESULTS Eleven cohort studies were included in this meta-analysis to estimate the relationship between event-free survival and 16q LOH in patients with WT(I^(2)=25%,P<0.001).As expected,16q LOH can serve as an effective predictor of eventfree survival in patients with WT(risk ratio=1.95,95%CI:1.52–2.49,P<0.001).CONCLUSION In pediatric patients with WT,there exists a partial correlation between 16q LOH and an unfavorable treatment prognosis.Clinical detection of 16q chromosome LOH warrants increased attention to the patient’s prognosis.

Event-triggered Tracking Consensus with Packet Losses and Time-varying Delays

This paper mainly investigates the event-triggered tracking control for leader-follower multi-agent systems with the problems of packet losses and time-varying delays when both the first-order and the second-order neighbors' information are used. Event-triggered control laws are adopted to reduce the frequency of individual actuation updating under the sampleddata framework for discrete-time agent dynamics. The communication graph is undirected and the loss of data across each communication link occurs at certain probability, which is governed by a Bernoulli process. One numerical example is given to demonstrate the effectiveness of the proposed methods. It is found that the tracking consensus is sped up by using the second-order neighbors' information when packet losses and time-varying delays occur. © 2014 Chinese Association of Automation.

Fault Tolerant Control for Networked Control Systems with Packet Loss and Time Delay

In this paper,a fault tolerant control with the consideration of actuator fault for a networked control system （NCS） with packet loss is addressed.The NCS with data packet loss can be described as a switched system model.Packet loss dependent Lyapunov function is used and a fault tolerant controller is proposed respectively for arbitrary packet loss process and Markovian packet loss process.Considering a controlled plant with external energy-bounded disturbance,a robust H ∞ fault tolerant controller is designed for the NCS.These results are also expanded to the NCS with packet loss and networked-induced delay.Numerical examples are given to illustrate the effectiveness of the proposed design method.

Probabilistic seismic loss estimation via endurance time method

Probabilistic Seismic Loss Estimation is a methodology used as a quantitative and explicit expression of the performance of buildings using terms that address the interests of both owners and insurance companies. Applying the ATC 58 approach for seismic loss assessment of buildings requires using Incremental Dynamic Analysis （IDA）, which needs hundreds of time-consuming analyses, which in turn hinders its wide application. The Endurance Time Method （ETM） is proposed herein as part of a demand propagation prediction procedure and is shown to be an economical alternative to IDA. Various scenarios were considered to achieve this purpose and their appropriateness has been evaluated using statistical methods. The most precise and efficient scenario was validated through comparison against IDA driven response predictions of 34 code conforming benchmark structures and was proven to be sufficiently precise while offering a great deal of efficiency. The loss values were estimated by replacing IDA with the proposed ETM-based procedure in the ATC 58 procedure and it was fotmd that these values suffer from varying inaccuracies, which were attributed to the discretized nature of damage and loss prediction functions provided by ATC 58.

Investigating path loss characteristics of UWB signals in vacancy indoor environment based on time-domain technique

The path loss analysis model based on 5 rays in vacancy indoor environment is proposed. The relationship between multipath overlapping and the path loss is analyzed mathematically. Time-domain technique is introduced to compute reflection coefficient in a very short time interval. A 5 rays path loss calculation method, which is satisfactory accurate, is developed. 5 typical environments are involved to analyze and generalize the common path loss characteristics in vacancy indoor environment. The simulation result shows that the path loss can be characterized as 3 zones with different path loss exponent as distance between transmitter and receiver increasing.

A consensus time synchronization protocol in wireless sensor network

Time synchronization is one of the base techniques in wireless sensor networks(WSNs).This paper proposes a novel time synchronization protocol which is a robust consensusbased algorithm in the existence of transmission delay and packet loss.It compensates for transmission delay and packet loss firstly,and then,estimates clock skew and clock offset in two steps.Simulation and experiment results show that the proposed protocol can keep synchronization error below 2μs in the grid network of 10 nodes or the random network of 90 nodes.Moreover,the synchronization accuracy in the proposed protocol can keep constant when the WSN works up to a month.

Robust fault detection for delta operator switched fuzzy systems with bilateral packet losses

Considering packet losses, time-varying delay, and parameter uncertainty in the switched fuzzy system, this paper designs a robust fault detection filter at any switching rate and analyzes the H∞ performance of the system. Firstly, the Takagi-Sugeno(T-S) fuzzy model is used to establish a global fuzzy model for the uncertain nonlinear time-delay switched system,and the packet loss process is modeled as a mathematical model satisfying Bernoulli distribution. Secondly, through the average dwell time method and multiple Lyapunov functions, the exponentially stable condition of the nonlinear network switched system is given. Finally, specific parameters of the robust fault detection filter can be obtained by solving linear matrix inequalities(LMIs). The effectiveness of the method is verified by simulation results.

The Role of a Novel Discrete-Time MRAC Based Motion Cueing on Loss of Control at a Hexapod Driving Simulator

The objective of this paper is to present the advantages of Model reference adaptive control (MRAC) motion cueing algorithm against the classical motion cueing algorithm in terms of biomechanical reactions of the participants during the critical maneuvers like chicane in driving simulator real-time. This study proposes a method and an experimental validation to analyze the vestibular and neuromuscular dynamics responses of the drivers with respect to the type of the control used at the hexapod driving simulator. For each situation, the EMG (electromyography) data were registered from arm muscles of the drivers (flexor carpi radialis, brachioradialis). In addition, the roll velocity perception thresholds (RVT) and roll velocities (RV) were computed from the real-time vestibular level measurements from the drivers via a motion-tracking sensor. In order to process the data of the EMG and RVT, Pearson’s correlation and a two-way ANOVA with a significance level of 0.05 were assigned. Moreover, the relationships of arm muscle power and roll velocity with vehicle CG (center of gravity) lateral displacement were analyzed in order to assess the agility/alertness level of the drivers as well as the vehicle loss of control characteristics with a confidence interval of 95%. The results showed that the MRAC algorithm avoided the loss of adhesion, loss of control (LOA, LOC) more reasonably compared to the classical motion cueing algorithm. According to our findings, the LOA avoidance decreased the neuromuscular-visual cues level conflict with MRAC algorithm. It also revealed that the neuromuscular-vehicle dynamics conflict has influence on visuo-vestibular conflict;however, the visuo-vestibular cue conflict does not influence the neuromuscular-vehicle dynamics interactions.

基于自抗扰的永磁同步电机附加谐波损耗抑制方法

针对永磁同步电机在变频器供电时,由时间电流谐波所引起的附加谐波损耗过大及难以在电机初始设计时被考虑到的问题,采用场路耦合联合仿真模型来计算电机的附加谐波损耗,并以4台现有的表贴式永磁同步电机为例,通过实验验证了场路耦合联合仿真模型的有效性,为电机设计之初附加谐波损耗的选取,以及后续温升的计算提供了前期计算的方法。同时提出一种基于自抗扰技术的附加谐波损耗抑制方法,设计一种适用于永磁同步电机矢量控制的自抗扰控制器,并从理论上验证了自抗扰控制器对于时间电流谐波的抑制作用,以及针对自抗扰控制器参数众多调参困难的问题,给出一种参数整定方案。最后通过引入所设计的自抗扰控制器,对电机的时间电流谐波进行计算和分析,使电机的附加谐波损耗降低了68.1%,为同类型电机的附加谐波损耗抑制提供了一种有效的方法。

电气设备剩余电压测试仪校准方法

分析了电气设备剩余电压测试仪基本原理,提出一种基于标准阻容网络法对剩余电压测试仪剩余电压幅值和延迟时间参数进行校准的方法。结合交流标准电阻器和电容器等效模型,分析了标准电阻时间常数和标准电容损耗因数对校准结果的影响,推导了校准时剩余电压和延迟时间标准值的计算方法。采用1 MΩ交流标准电阻和1μF标准电容器组成的电路网络对剩余电压测试仪进行了校准,结果表明标准阻容网络法可满足该仪器的校准。对测量结果进行了不确定度分析,剩余电压幅值测量不确定度为1.1%,延迟时间测量不确定度为1.2%,主要不确定度分量为标准电容器损耗因数的影响。

晚间授课会导致大学生课程成绩的“无谓损失”吗?

课程成绩是学生学习和个人发展的重要风向标。优化课堂教学安排减少课程成绩无谓损失是目前高校教务部门关注的热点问题。本文从排课时间视角实证讨论了课堂教学安排对大学生课程成绩的影响。研究表明:(1)晚上进行课堂教学会导致学生课程成绩下降。(2)对于同一教学班而言,所有课堂教学均在晚上进行,将带来严重的课程成绩损失。(3)晚上进行必修课程教学和采用多位教师协同教学能够缓释晚上教学带来的课程成绩损失。据此,为缓释晚上教学带来的课程成绩损失,应当深入推进教学范式改革,尽量避免晚上教学;完善教学安排系统,妥善考虑课程性质差异;推动课程组深度教学合作,施行同课师资交叉授课。

基于熵变匹配追踪的叶端定时数据缺失识别方法研究

为解决叶端定时系统在实际应用中存在的数据缺失问题,提出基于熵变匹配追踪的叶端定时数据缺失识别方法。该方法利用相关熵诱导度量基于高斯核函数度量样本的权重。不同于正交匹配追踪对所有观测数据赋予相同权重,熵变匹配追踪基于相关熵诱导度量变化,对观测数据赋予不同范数类型的权重,使得其对异常值具有较好的鲁棒性。通过仿真分析与实验对该方法的性能进行验证,结果显示所采用的熵变权重因子为数据缺失位置分配了接近于零的权重,有效降低了数据缺失对特征提取结果的影响,证明了该方法的鲁棒性。基于熵变匹配追踪的叶端定时数据缺失识别方法为叶端定时系统的装机应用提供了理论支撑,具有技术借鉴价值。

“阿尔法城”记忆:村上春树文学的“近代”景观

村上春树与美国作家菲茨杰拉德分属不同的时代和社会,他们通过文学创作积极思索“近代”资本主义席卷世界过程中出现的困扰人类社会的同质性问题。在长篇小说《天黑以后》中,村上春树借用法国电影《阿尔法城》的隐喻,描述了当下日本社会在个人感情、战争记忆上的失落;进而通过叙述二重奏的创作手法,揭示人们如何失去正常的生活,又渐渐堕入人性丧失的泥沼;最后,将人性恶亦即“本源恶”问题指向“近代”及其系统,思考科技发达的“近代”社会中,人之为人的真实意义究竟何在。

基于多尺度与注意力机制的两阶段风暴单体外推研究

风暴是一种生命周期短、发生突然、空间尺度小的自然现象,常用雷达回波外推方法进行预测,但时序预测模型难以在众多特征中定位风暴关键信息,导致预测精度低,模型无法充分学习图像高频信息,导致预测细节缺失,结果模糊。为了提升预测性能,提出两阶段风暴单体外推框架。第一阶段使用多尺度模块提取多尺度信息,注意力机制挖掘影响预测的重要特征,使用时空长短期记忆单元进行序列预测。第二阶段对一阶段结果进行偏差矫正,使用频域损失丰富外推细节。实验结果表明,在雷达回波数据集上,与主流模型PredRNN-V2相比,该模型均方误差降低11.4%,SSIM提升4.3%,在风暴单体外推任务中表现优越。在Moving MNIST数据集上,均方误差降低4.95%,感知损失降低12.67%,SSIM提升至0.898,具有良好的时序预测能力。

高空电磁脉冲晚期成分作用下500 kV变压器无功损耗仿真研究

高空电磁脉冲晚期成分(HEMP E3)效应会在变压器中性点与大地构成的回路中产生地磁感应电流(GIC),严重时会使变压器铁心半波饱和,进而导致励磁电流严重畸变、无功损耗急剧增加、局部过热和振动加剧等后果。为准确地分析电力变压器在HEMPE3作用下的无功损耗特性,该文搭建了HEMP E3对500 kV电力变压器作用的电磁暂态仿真模型,基于IEC 61000-2-9给出的标准HEMP E3波形,定量分析了感应电场幅值、上升时间、下降时间以及变压器带负载情况等对电力变压器的影响规律。分析结果表明,HEMP E3作用下500 kV变压器无功损耗与GIC呈正相关性,且无功损耗波形滞后于感应电场的变化;HEMP E3感应电场的下降时间对500 kV变压器无功损耗的影响远超上升时间;负载阻抗的阻值相同时,容性负载下的励磁电流和无功损耗幅值最大,感性负载下幅值最小。研究结果可为进一步评估HEMPE3对电力系统稳定性的影响提供重要依据。

基于改进DTW算法的永磁同步电机失磁故障模拟与诊断

为实现永磁同步电机(permanent magnet synchronous motor,PMSM)失磁故障模拟与失磁故障程度诊断,提出一种基于改进的动态时间规整(dynamic time warping,DTW)算法的故障波形诊断方法。首先,对永磁同步电机进行机理分析和模拟,采集不同程度失磁故障下的电机转速波形数据集。其次,使用改进DTW算法拟合失磁故障程度最佳路径曲线方程。然后,根据定子电流的频率谐波分量确定电机是否发生失磁故障。最后,使用改进DTW算法对失磁故障波形数据进行故障程度诊断。实验表明,该方法对故障波形数据进行处理后,可以快速准确地计算出故障波形的故障程度,该方法具备较强的稳定性和实时性。

肾部分切除术后急性肾损伤及其对手术侧肾脏的远期影响

肾部分切除术是治疗局限性小肾癌的首选方法,但手术过程中通常需要暂时阻断肾动脉,不可避免地引发缺血再灌注损伤,严重者甚至发生急性肾损伤。肾部分切除术后急性肾损伤的诊断常采用急性肾损伤网络标准(AKIN)和风险、损伤、失败、损失、终末期肾脏疾病标准(RIFLE),但使用总肌酐升高水平来评估单侧肾损伤显然不够准确;另外,肾部分切除术中会丢失部分正常肾组织,也导致血肌酐升高。为避免上述因素对诊断造成干扰,笔者首先改良了孤立肾肾部分切除术后急性肾损伤诊断分级方法,提出了诊断肾部分切除术后的急性肾损伤需要考虑到正常肾组织丢失引起的血肌酐升高。接着采用“极端值法”量化了非孤立肾患者手术侧肾脏急性肾损伤的程度。最后还探讨了急性肾损伤对手术侧肾脏的远期影响以及减轻肾部分切除术中缺血再灌注肾损伤的潜在方法。

碱性速凝剂对盾构壁后注浆浆体性能影响及微观机理研究

在盾构隧道壁后注浆工程中,选择合适的速凝剂,缩短壁后注浆浆体(浆体)的凝结时间,对控制地层沉降和管片上浮至关重要。采用Na_(2)CO_(3)和Li_(2)CO_(3)两种碱性速凝剂配制壁后注浆,分析了两者对浆体凝结时间、流动度经时损失和强度的影响规律及微观机制。结果表明:两类速凝剂均能明显缩短浆体的凝结时间,提高浆体强度,但同时导致浆体流动度经时损失加快。添加3%Na_(2)CO_(3)、0.5%Li_(2)CO_(3)分别使浆体凝结时间缩短至6.5 h和8 h,2.5 h后浆体流动度保持在220 mm,浆体14 d强度为3.8 MPa,相比未添加速凝剂浆体的强度提高30%以上。微观结构分析表明,碱性速凝剂通过与石膏和CH晶体反应,促进水泥矿物C_(3)A和C_(3)S水化,缩短了浆体的凝结时间;此外,碱性速凝剂促使水泥水化产生水滑石、方解石,并激发粉煤灰生成C-A-S-H,均使浆体结构更为致密,进而提高其后期强度。

基于焦点损失的ATCN-GRU语音情感识别

为了改善RNN的空间信息丢失和CNN忽略时序信息的问题,引入了时间卷积网络TCN,将上述网络与双向门控循环单元Bi-GRU以及注意力机制组合构建了声学模型ATCN-GRU来进一步提高语音情感识别的性能,并通过加入焦点损失改善EMODB和IEMOCAP数据库训练样本不平均导致的识别结果不均衡问题。首先,通过TCN残差块从手工提取的特征中选取最具有代表性和鲁棒性的特征;其次,利用Bi-GRU模型学习语音样本的上下文相关信息,并利用注意力机制学习模型的输入序列与输出序列之间的关联程度,从而给予有效信息更多关注;最后,通过Softmax层对情感进行分类。相较于前人的研究成果,模型ATCN-GRU取得了更好的识别性能:在CASIA、EMODB以及IEMOCAP三个数据库上分别取得了88.17%、85.98%和65.83%的平均准确率;引入焦点损失后,EMODB和IEMOCAP数据库上的平均准确率分别达到了86.26%和66.30%。

低插入损耗的5~14 GHz慢波时延器芯片设计

基于0.15μm E/D pHEMT工艺,设计了一款新型慢波线结构的时延器芯片。该时延器芯片集成了慢波时延线、单刀双掷开关和数字驱动器等功能芯片,其中,慢波时延线通过电磁仿真软件优化慢波结构的长度、间距以及拐角的结构,可以优化时延器的性能,提高集成度;单刀双掷开关采用具有高隔离度和低损耗的串并混合结构;数字驱动器采用高度集成pHEMT工艺,稳定输出两路反相电平。在片测试结果表明:在5~14 GHz频段内,芯片总插入损耗小于8.5 dB,中心频点延时量850 ps,输入输出驻波小于1.7,寄生调幅小于±0.8 dB,静态功耗1 mA@-5 V。芯片版图面积为6.7 mm×5.0 mm。