Effect of varying levels of mental workload on startle eyeblink modulation

Previous research using punctuate reaction time and counting tasks has found that the startle eyeblink reflex is sensitive to attentional demands. The present experiment explored whether startle eyeblink is also modulated during a complex continuous task and is sensitive to different levels of mental workload. Participants (N = 14) performed a visual horizontal tracking task either alone (single-task condition) or in combination with a visual gauge monitoring task (multiple-task condition) for three minutes. On some task trials, the startle eyeblink reflex was elicited by a noise burst. Results showed that startle eyeblink was attenuated during both tasks and that the attenuation was greater during the multiple-task condition than during the single-task condition. Subjective ratings, endogenous eyeblink rate, heart period, and heart period variability provided convergent validity of the workload manipulations. The findings suggest that the startle eyeblink is sensitive to the workload demands associated with a continuous visual task. The application of startle eyeblink modulation as a workload metric and the possibility that it may be diagnostic of workload demands in different stimulus modalities is discussed.     

Automatic prediction of time to failure of open pit mine slopes based on radar monitoring and inverse velocity method简

Radar slope monitoring is now widely used across the world, for example, the slope stability radar (SSR) and the movement and surveying radar (MSR) are currently in use in many mines around the world. However, to fully realize the effectiveness of this radar in notifying mine personnel of an impending slope failure, a method that can confidently predict the time of failure is necessary. The model developed in this study is based on the inverse velocity method pioneered by Fukuzono in 1985. The model named the slope failure prediction model (SFPM) was validated with the displacement data from two slope failures monitored with the MSR. The model was found to be very effective in predicting the time to failure while providing adequate evacuation time once the progressive displacement stage is reached.     

光纤陀螺仪测试系统设计与软件实现

介绍了一套光纤陀螺仪自动化测试系统,测试系统可以完成光纤陀螺静态测试、速率测试和环境试验测试等。测试系统硬件主要包括测试工控机、数据采集卡及环境测试设备,测试软件基于MicrosoftWindows系统和Microsoft Visual C++6.0软件开发平台。测试系统可以实现多通道光纤陀螺数据采集、分析与处理、动态显示,并控制速率转台和高低温试验箱等环境试验设备完成光纤陀螺多种性能测试。实际应用表明,自动化测试系统可以大大提高光纤陀螺的测试效率,满足批量化生产的需求,实现了测试过程的标准化。     

车载跳频电台共址干扰研究及其优化

针对车载VHF跳频电台的共址干扰问题,建立一种定频模式下的共址干扰分析模型。分析共址干扰的主要影响因素,通过实验和理论研究对干扰功率、频率、误码率等重要参数进行定量分析,建立定频模式下的共址干扰分析模型。结合VHF组网的约束条件,提出一种跳频系统的误码率计算方法,并采用双层多目标算法,构建基于共址电台规模和频表分配的优化设计模型。实例分析表明,该模型可优化配置电台工作参数,有效降低共址跳频电台误码率。     

基于矩阵模型的线性分组码及分组交织识别

针对通信系统中错误不可避免的现状,在矩阵分析法的基础上,提出反向纠错思想。利用穷举法,穷举条件规定范围内所有可能的分组码和分组交织模式,在纠错译码后再进行判定,得出正确的交织参数。对该方法在不同的误码率条件下进行仿真,得出能够正确识别的误码范围。     

基于神经元网络的选择型问卷识别技术

在问卷调查数据自动识别和统计过程中,由于纸张的折叠、弯曲、变形及受污染等原因引起的数据误判时有发生,考虑到手工统计的繁杂性,开发一种自动、高效的智能处理系统具有相当大的实用价值。提出应用神经网络对调查问卷扫描图像进行识别处理的方法,建立基于MATLAB的Hopfield网络识别模型,并详细讨论了图像预处理、特征提取及Hopfield网络训练与识别这三个重要环节。针对建立好的识别模型,系统仿真情况下,符号识别率达到100%;在实际操作过程中,当训练样本数充足,样本来源可靠的情况下,识别率高达96%,基本实现预期效果。     

一种中继节点上的网络-信道编码联合设计方案

网络编码技术由于其能提高网络吞吐量、具有较好的鲁棒性、能有效提高中继节点转发效率等优点成为目前广泛关注的研究热点。在中继节点上,采用网络一信道编码联合设计方案能进一步提高系统的误码性能。基于Razaghi等人研究的两种双层LDPC码（Bilayer LDPC,分为删余型和延长型）,设计了一种在中继节点上联合设计的网络双层LDPC延长码（Network Bilayer Lengthened LDPC,NBL—LDPC）。给出了此码的编译码过程,并针对此码,对高斯密度进化算法进行改进,计算误码率并完成误码性能仿真。仿真结果表明,所提出的编码方案性能要优于利用双层LDPC删余码设计的网络双层LDPC删余码（Network Bilayer Expurgated LDPC,NBE—LDPC）。     

PEG分子量对PET—PEG共聚酯结晶性能的影响

通过ＰＥＴ和ＰＥＧ共缩聚，合成了ＰＥＴ—ＰＥＧ共聚酯，采用ＤＳＣ、等温结晶仪、Ｘ衍射分析仪和电子扫描电镜研究了ＰＥＧ分子量对该共聚酯结晶性能的影响。结果表明，在ＰＥＴ分子结构中引入ＰＥＧ链段，能有效提高结晶速度，共聚酯结晶结构与ＰＥＴ类似，但ＰＥＧ不进入晶格中，只起诱导结晶的作用。当ＰＥＧ分子量为４０００时，冷结晶温度Ｔｃｃ降得最低，但热结晶温度Ｔｃ反而比纯ＰＥＴ有所增加，１１０℃结晶速度ｔ１２＝１ｍｉｎ，而纯ＰＥＴ需１２ｍｉｎ。     

High density polyethylene (HDPE): Experiments and modeling

The uniaxial tension (loading and unloading), creep and relaxation experiments on high density polyethylene (HDPE) have been carried out at room temperature. The stress–strain behavior of HDPE under different strain rates, creep (relaxation) behavior at different stress (strain) levels have been investigated. These experimental results are used to compare the simulation results of a unified state variable theory, viscoplasticity theory based on overstress (VBO) and a macro-mechanical constitutive model for elasto-viscoplastic deformation of polymeric materials developed by Boyce et al. (Polymer 41:2183–2201, 2000). It is observed that elasto-viscoplasticity model by Boyce et al. (Polymer 41:2183–2201, 2000) is not good enough to simulate stress–strain, creep and relaxation behaviors of HDPE. However, the aforementioned behaviors can be modeled quantitatively by using VBO model.     

OSCA-CFAR在K分布杂波背景下的性能分析

本文证明了形状因子已知条件下有序统计平均（OSCA）恒虚警检测器在K分布杂波背景下具有恒虚警性能，分析了均匀K分布杂波背景和多目标情况下该检测器的性能，并与OS和OSGO-CFAR进行了比较，仿真结果表明OSCA在两种环境下均具有最好的检测性能。