An EEG Brain–Computer Interface Approach for Classifying Vigilance States in Humans: A Gamma Band Focus Supports Low Misclassification Rates

This research investigated a brain–computer interface (BCI) for classifying vigilance states. A BCI approach based on event-related potential (ERP) and spectral features of electroencephalographic (EEG) data derived from an auditory oddball paradigm was employed. A 128-channel EEG system recorded potentials while participants simultaneously completed a prolonged visual match-to-sample task. It was hypothesized that better classification rates would be found for a group of “bored” participants, as compared to the not-bored participants. The best classification rates were found by extracting EEG features from gamma frequencies at middle and late latencies (for the standard tones). Critically, the BCI paradigm was most effective for the bored participants (mean misclassification rate = 13%), as compared to the not-bored participants (mean misclassification rate = 21%). These findings extend our knowledge of reliable latencies and spectral features of ERP data most salient to the classification of vigilance states.     

基于偏最小二乘法的事件相关电位单次提取研究

为满足脑-机接口特征提取实时性以及临床脑电检测高效性的要求,探讨事件相关电位的单试次高效提取技术尤为重要。将小波分析、经验模态分解、极限学习机以及偏最小二乘(PLS)应用于仿真和真实脑电信号,完成特征提取。结果显示:仿真实验中,不同信噪比下PLS提取性能稳定,P300潜伏期误差小于4 ms;真实脑电中,PLS少次迭代,特征提取更为精确,峰值误差0.551μV,峰值潜伏期偏移量27 ms,均小于小波、经验模态分解以及极限学习机多试次迭代结果(P<0.01)。结果表明偏最小二乘法在事件相关电位单试次提取中具有显著优势。     

ICA及其在事件相关电位P3中的应用

针对事件相关电位(Event-relatedPotential,ERP)P3复合波中的亚成分较难分离的问题,运用近年新兴起来的独立分量分析(IndependentComponentAnalysis,ICA)算法对多道事件相关电位P3复合波进行了分解。实验结果表明:利用ICA可将混合在观测信号中的相互独立的源信号分离出来的特性,成功地分离出了P3复合波的各亚成分,从而表明了ICA在分离P3亚成分中的应用是一个值得注意的研究方向。     

基于SPCE061A的智能轮椅控制系统硬件设计

随着人口老龄化问题越来越严重以及人民生活水平的提高,无论是高龄老年人还是先天或后天肢残者对轮椅等辅助步行工具的需求将日益迫切。在脑电设备的发送和接收控制端加入了基于SPCE061技术的语音识别系统,当大脑发出操作意图时,该信号经过处理触发语音播报系统,而受控设备上安装的语音接收端经过语音辨识,发出正确的驱动信息并进行语音播报,从而控制轮椅的电机系统,如果驾驶者从听觉上感知到信息错误,可及时调整大脑意识,从而实现脑电识别和语音识别对智能轮椅的双保险控制,为有肢体障碍的残疾人提供一种新的控制方式。     

基于嵌入式系统的能谱型核测井仪器

介绍了能谱型核测井仪的设计方案,其目标是研制适用于铀矿勘查的便携式测井仪,满足测井生产的需要。该仪器采用碲锌镉CdZnTe半导体核辐射探测器,高端的32位嵌入式ARM处理器S3C2410A为仪器系统控制核心,并在此硬件平台上移植了嵌入式Linux操作系统,编写了基于MiniGUI的测井仪监控终端软件。仪器具有实时性、体积小、功耗低、灵敏度高、成本低、便于携带等特点。     

基于MCF51QE128的SD卡接口设计

SD（Secure Digital）卡是一种基于闪存技术的可移动存储设备,由于其体积小、功耗低、容量大且成本低,广泛应用于各类小型便携式电子设备中。本文实现了SD卡与Freescale公司的32位低功耗微控制器MCF51QE128之间的软硬件接口设计,可作为数据记录仪、媒体播放器和录音设备等的设计参考。     

High-level control of sound synthesis for sonification processes

Methods of sonification based on the design and control of sound synthesis is presented in this paper. The semiotics of isolated sounds was evidenced by performing fundamental studies using a combined acoustical and brain imaging (event-related potentials) approach. The perceptual cues (which are known as invariants) responsible for the evocations elicited by the sounds generated by impacts, moving sound sources, dynamic events and vehicles (car-door closing and car engine noise) were then identified based on physical and perceptual considerations. Lastly, some examples of the high-level control of a synthesis process simulating immersive 3-D auditory scenes, interacting objects and evoked dynamics are presented.     

An efficient implementation of a low-complexity MP3 algorithm with a stream cipher

For portable devices with MP3 codec, the demands of digital right management arise recently. To provide a secure scheme to the most portable devices with MP3 codec, this work efficiently implements a secure MP3 algorithm on a dual-core system with one DSP and one RISC. The secure MP3 algorithm is a combination of a proposed low-complexity MP3 algorithm and a stream cipher. The low-complexity MP3 algorithm is executed on DSP and the stream cipher is on RISC. This separated design can dynamically update the type of stream ciphers in various applications. However, some of the main data, rather than an entire MP3 file, is encrypted in the MP3 frame. The partially encrypted data have variable size, determined by the specified security level. The security scheme offers two advantages. The first is that the encrypting and decrypting structures are identical. The second is that the scheme easily determines the quality of the encrypted MP3. For saving the computational power to obtain long playing time for a portable device, a low-complexity MP3 encoder and decoder are implemented using ADSP-2181 with 16-bit fixed-point data precision. MP3 encoding requires only 27.2 KB/16.8 KB (data RAM/program RAM), and decoding requires 23.6 KB/20.7 KB for decoder. The peak MIPS of the encoder and decoder are 21.05 and 17.67, respectively. This work can be applied to a Digital Rights Management (DRM) system for limiting the access of the music.     

Portable real-time software for 8-bit microprocessors

This paper discusses a method for developing efficient and portable software for 8-bit microprocessors used in real-time applications. The technique used is to design an ‘intermediate level language’ (ILL) which defines low-level primitives to support the real-time application programming and the constructs of high level languages. Thus, the high level language (HLL) program goes through two stages of translation; first to the ILL code and then to the machine code of a microprocessor. The ILL instruction set developed bridges the gap between high level languages and the poor instruction set of microprocessors. This allows the development of optimized and portable code for the microprocessors. The ILL operations, data types, data organization, control structures, synchronization, communication and multi-tasking facilities are described. The effectiveness of this technique is shown by comparing the code generated by the ILL approach with the code available for a sample real-time application written directly in assembly level language.     

The impact of interface-induced handling requirements on action generation in technical system control

In analysing action generation in technical system control we differentiate between a purely cognitive stage of pre-actional decision-making and an action-related cognitive-physical stage of action planning and plan execution. This study investigates the impact of interface-induced handling requirements on the action-related processes in the domain of artificial respiration in intensive care. Thirty-two novice and experienced intensive care nurses had to solve three realistic control tasks on two types of respiration unit equipped either with an 'analogue' or with a 'digital' user interface. The quality of the novices' plan execution and—unexpectedly— action planning, too, decreased when working on the 'digital' interface. Interface-induced handling requirements obviously have an important influence on the usability of technical systems not only on a purely cognitive level, but also on the action-related level.     

一个高可移植性的轻量级x86模拟器

介绍一个可以在多种处理器体系结构上运行的轻量级x86模拟器PIT(Portable x86 Instruction Translator)."动态二进制指令翻译"足一个可以让一种机器的指令运行在另一种机器上的技术.PIT采用了可移植的动态二进制指令翻译技术,可以在多种体系结构(包括x86,PowerPC,ARM,Spa...     

基于事件相关电位的脑－机接口系统微弱信号分析方法研究

脑－机接口(BCI,brain computer interface)技术作为一种新型的人机交互方式,近年来受到越来越多的关注。基于听觉刺激模式诱发的事件相关电位P300建立了脑－机接口系统,主要研究微弱P300信号的单导联小样本数据的特征提取和模式识别方法。首先经过预处理和小波变换对脑电信号中的P300成分进行特征提取,建立特征向量,然后使用支持向量机的方法对特征提取结果进行模式分类。对7名受试者进行事件相关电位P300诱发实验,结果表明,系统的分类正确率可达到85％以上,且支持向量机的训练时间都在0.05 s以内。该方法可为脑－机接口的进一步应用奠定基础。     

神经皮质运动区功能定位的皮层慢电位小波分析

探讨皮质脑电中皮层慢电位小波分析用于术中神经皮质(运动区)功能定位的方法.利用离散db5小波对皮质脑电信号数据进行8层小波分解并重构各单子频带信号,提取运动事件相关皮层慢电位在运动事件发生前后的能量比(ERP指标)为特征量,并构造特定阈值进行分类,结果与相应手指弯曲运动数据比较,进行检测正确率分析.将试验采集数据分成训练和测试组,分别用于特征提取方法和分类器的设计和性能检测,进行检出正确率分析.以皮层慢电位信号的ERP指标为特征量,以1.6为阈值进行分类,其分类定位检出正确率达到84%.通过皮质(运动区)皮层慢电位的小波分析方法可以更有效地进行术中运动功能区皮质定位的特征提取和分类.     

基于稳态视觉诱发电位的在线脑机接口研究

针对脑机接口中存在的抗噪声能力差、操作复杂的问题,利用便携式脑电采集设备Emotiv EPOC以及NAO机器人,搭建了一个抗噪能力较好的稳态视觉诱发在线脑机接口系统。该系统采用典型相关性分析进行稳态视觉诱发电位的频率识别。在线实验中受试者通过Emotiv控制NAO机器人运动,四类任务的准确率达到87.50%。在线实验没有回避周围的噪声,表明该系统具有较好的抗噪能力。     

The impact of interface-induced handling requirements on action generation in technical system control

Abstract

In analysing action generation in technical system control we differentiate between a purely cognitive stage of pre-actional decision-making and an action-related cognitive-physical stage of action planning and plan execution. This study investigates the impact of interface-induced handling requirements on the action-related processes in the domain of artificial respiration in intensive care. Thirty-two novice and experienced intensive care nurses had to solve three realistic control tasks on two types of respiration unit equipped either with an ‘analogue’ or with a ‘digital’ user interface. The quality of the novices’ plan execution and—unexpectedly— action planning, too, decreased when working on the ‘digital’ interface. Interface-induced handling requirements obviously have an important influence on the usability of technical systems not only on a purely cognitive level, but also on the action-related level.     

ADS1298模拟前端的便携式生理信号采集系统

介绍了一种便携式多功能生理信号采集装置,用户通过简单设置及选择相应电极,可分别进行脑电和心电数据的实时采集,并能对数据进行显示和存储。它具有精度高、体积小、功耗低等特点。该系统下位机主要由ST公司的STM32单片机STM32F103和TI公司的ADS1298模拟前端IC构成,省去了大量的外围电路。下位机通过USB2．0...     

新型便携式岩体声发射监测仪

论述了岩体声发射监测原理,介绍了专门开发的新型便携式岩体声发射监测仪的结构及特点,对其技术难点提出了解决途径。     

一种基于EEG和sEMG的假手控制策略

针对残臂较短或残臂上肌电信号测量点较少的残疾人使用多自由度假手的需求,提出一种基于脑电信号（Electroencephalogram,EEG）和表面肌电信号（Surface electromyogram signal,sEMG）协同处理的假手控制策略.该方法仅用1个肌电传感器和1个脑电传感器实现多自由度假手的控制.采用1个脑电传感器测量人体前额部位的EEG,从测量得到的EEG中提取出眨眼动作信息并将其用于假手动作的编码;采用1个肌电传感器测量手臂上的sEMG,并针对肌电信号存在个体差异和位置差异的问题,采用自适应方法实现手部动作强度的估计;采用振动触觉技术设计触觉编码用于将当前假手的控制指令反馈给佩戴者,从而实现EEG和sEMG对多自由度假手的协同控制.为验证该控制策略的有效性进行了实验研究,结果表明,提出的假手控制策略是有效的.     

SH3: high code density, low power

Hitachi's SH series microprocessors feature 32-bit RISC architecture with a 16-bit, fixed-length instruction set. We describe SH3, a pipelined implementation of the SH architecture with on-chip cache, MMU, and software-programmable power management. Its higher code density and corresponding improvement in instruction-fetch latency lead to higher performance than typical 32-bit RISC architectures achieve. These features, small die size, and low power consumption make SH3 an ideal microprocessor for portable computing systems or multimedia systems     

设备级实时多任务嵌入式内核WebitV的设计与实现

使用实时内核来进行多任务的管理是目前嵌入式应用的一个趋势，面向设备的嵌入式应用由于其资源受到严重限制,具有针对性强的特点，本文在一个8位嵌入式芯片上设计并实现了一个面向设备的抢占式实时多任务内核WebitV，它在总体上保留了传统内核的主要特性，但在任务调度，优先级分配以及存储器管理等几个方面进行了改进，使它更适合于设备计算，为普适计算提供了一个底层平台。