Principles of a brain-computer interface (BCI) based on real-time functional magnetic resonance imaging (fMRI)

A brain-computer interface (BCI) based on functional magnetic resonance imaging (fMRI) records noninvasively activity of the entire brain with a high spatial resolution. We present a fMRI-based BCI which performs data processing and feedback of the hemodynamic brain activity within 1.3 s. Using this technique, differential feedback and self-regulation is feasible as exemplified by the supplementary motor area (SMA) and parahippocampal place area (PPA). Technical and experimental aspects are discussed with respect to neurofeedback. The methodology now allows for studying behavioral effects and strategies of local self-regulation in healthy and diseased subjects.     

基于运动想象的异步在线脑-机接口系统

目前,运动想象脑-机接口( motor imagery brain computer interface,MIBCI) 的离线分析和研究相对比较成熟,但是异步在线MIBCI始终具有挑战性。针对在线BCI系统的识别率和控制方式,提出了利用共空间模式(common spatial pattern,CSP)算法对运动想象(motor imagery,MI)进行特征提取并结合alpha波进行异步控制。构建了一种简单实用的自主控制小球运动MIBCI实验系统。有四名受试者参加了在线实验,其中有两名受试者在线运动想象识别正确率最高能达到100%。实验结果验证了本文所建系统的可行性和实用性。      

An EEG-driven brain-computer interface combined with functional magnetic resonance imaging (fMRI)

Self-regulation of slow cortical potentials (SCPs) has been successfully used to prevent epileptic seizures as well as to communicate with completely paralyzed patients. The thought translation device (TTD) is a brain-computer interface (BCI) that was developed for training and application of SCP self-regulation. To investigate the neurophysiological mechanisms of SCP regulation the TTD was combined with functional magnetic resonance imaging (fMRI). The technical aspects and pitfalls of combined fMRI data acquisition and EEG neurofeedback are discussed. First data of SCP feedback during fMRI are presented.     

基于脑-机接口的智能小车系统设计与实现

结合嵌入式系统和脑-机接口技术,构建MindAuto———意念赛车系统。首先以TGAM为核心制作脑电采集设备MindReader,进行脑电数据的采集;其次通过蓝牙将MindReader和PC机相连,将采集到的脑波原始数据raw data、注意力值Attention、放松度值Meditation和眨眼强度值Blink传输到PC机,利用eSense算法将脑电数据进行量化;然后通过蓝牙无线连接到Arduino智能小车平台,通过I/O控制口实现脑波对小车的控制;最后结合多功能轨道模型,实现此控制系统。     

基于移动平台的脑电波游戏设计与实现

本项目是通过MindWave Mobile与手机终端的结合,设计了意念控制的射击游戏,使用MindWave Mobile耳机作为脑波接收器,通过蓝牙模块传输数据至移动终端,通过在移动终端上的游戏软件接受数据并处理,作为参数用于游戏控制,为玩家提供新鲜体验感用于娱乐的同时,也可用于训练用户的集中度.并且有助于分析人类集中度变化的函数曲线,采集的数据有助于分析人类大脑进行后续研究.并且本项目应实现MindWave Mobile耳机与手机终端的直接连接,而不需通过PC机作为中介平台,可广泛应用于智能移动终端游戏、教育及儿童注意力训练等领域.     

Design and implementation of a brain-computer interface with high transfer rates

This paper presents a brain-computer interface (BCI) that can help users to input phone numbers. The system is based on the steady-state visual evoked potential (SSVEP). Twelve buttons illuminated at different rates were displayed on a computer monitor. The buttons constituted a virtual telephone keypad, representing the ten digits 0-9, BACKSPACE, and ENTER. Users could input phone number by gazing at these buttons. The frequency-coded SSVEP was used to judge which button the user desired. Eight of the thirteen subjects succeeded in ringing the mobile phone using the system. The average transfer rate over all subjects was 27.15 bits/min. The attractive features of the system are noninvasive signal recording, little training required for use, and high information transfer rate. Approaches to improve the performance of the system are discussed.     

A mu-rhythm matched filter for continuous control of a brain-computer interface.

A brain-computer interface (BCI) is a system that provides an alternate nonmuscular communication/control channel for individuals with severe neuromuscular disabilities. With proper training, individuals can learn to modulate the amplitude of specific electroencephalographic (EEG) components (e.g., the 8-12 Hz mu rhythm and 18-26 Hz beta rhythm) over the sensorimotor cortex and use them to control a cursor on a computer screen. Conventional spectral techniques for monitoring the continuous amplitude fluctuations fail to capture essential amplitude/phase relationships of the mu and beta rhythms in a compact fashion and, therefore, are suboptimal. By extracting the characteristic mu rhythm for a user, the exact morphology can be characterized and exploited as a matched filter. A simple, parameterized model for the characteristic mu rhythm is proposed and its effectiveness as a matched filter is examined online for a one-dimensional cursor control task. The results suggest that amplitude/phase coupling exists between the mu and beta bands during event-related desynchronization, and that an appropriate matched filter can provide improved performance.     

A file system for a general-purpose time-sharing environment

The file system for the Michigan terminal system (MTS) is described. MTS is a general-purpose multiprogramming multiprocessing paged time-sharing system for the IBM 360/67 and 370/168 developed at the University of Michigan, Ann Arbor. First, an overview of some of the external facilities provided to the users of files is presented; then some of the internal design philosophy and corresponding implementation strategy for the file system are discussed. Particular emphasis is placed on how the sharing of files is accomplished, both from the user's point of view and the system's point of view. A retrospective judgment of some of the strengths and weaknesses of the MTS file system is given. Finally, an appendix details the allowable concurrent usage of files and the algorithm used for file deadlock detection in MTS.     

Development of intracranial brain-computer interface system using non-motor brain area for series of motor functions

An intracranial brain-computer interface (BCI) system using the neuronal activity of a non-motor brain area to fulfil a series of motor functions has been developed. The presented BCI system encodes a series of motor functions into a small number of neuronal units of the primary somatosensory cortex of a rat and generates real-time command signals to control a machine according to the animal's motor intentions. The results of this study demonstrate the practical usability of the BCI system using a non-motor brain area in the field of rehabilitation.     

Use of a time-shared general-purpose file-handling system in hospital research

Techniques in automated data-handling for medical research and patient-care purposes are being investigated using a conversational timeshared computer system. This paper covers the initial design considerations, implementation experience, and user reaction with the prototype set of on-line, multiple-access, general-purpose information storage and retrieval programs. This system is designed to pemit hospital personnel (without the need for special assistance or any direct intervention by trained computer programmers) to define and establish private data files, to enter or change moderately large volumes of English text or coded data, and to retrieve and manipulate selected output information. Hospital staffs, from remote terminals, have been using this system on an operational basis for more than a year. The development and implementation of the system is being carried out by Bolt Beranek and Newman Inc., and the Massachusetts General Hospital, under the support of the National Institutes of Health.     

Equivalent Circuit Model of a Bundle of Cables for Bulk Current Injection (BCI) Test

A "simulation program with integrated circuit emphasis" (SPICE) model for the evaluation, in frequency and time domain, of the coupling of a bundle of shielded coaxial cables with an external electromagnetic source such as a bulk current injection clamp, is developed. The proposed equivalent circuit takes into account the presence of the transfer impedance and the presence of the transfer admittance, and it does not need the subdivision in elementary cells. Intermediate results are validated by comparing the exact numerical solutions with the output of the SPICE circuit, and the final results are validated by means of comparison with measurements carried out on an experimental setup. The feature selective validation (FSV) technique is used as a measure of the comparisons     

基于嵌入式系统和PL2000A型调制解调器的电力线载波通信接口设计

电力线通信存在信号衰减快、线路阻抗经常波动等诸多问题,使得通过电力线通信有较大的困难,PL2000A型电力线扩频载波通信专用电路能为此类问题提供较好的解决方案.介绍基于嵌入式系统和PL2000A的载波通信功能的应用接口,分析基于该电路的低压电力线载波通信应用的设计原理,给出相应的电路图和部分软件代码.     

The new AP101S general-purpose computer (GPC) for the space shuttle

This paper describes the development of the new AP101S General-Purpose Computer (GPC) for the Space Shuttle Orbiter. The GPC is the primary data processing computer on-board the Shuttle. It controls and monitors spacecraft functions. In recent years, the requirements for expanding the Shuttle's capabilities have surpassed the capabilities of the current GPC, the AP101B. This upgrade necessity and expected longevity of the Space Shuttle program has given birth to the AP101S GPC. The AP101S evolved from a line of pipeline processors flexible enough to support the Space Shuttle requirements. It offers many features vital to the expected needs of the space program. This paper describes the design philosophy, methodology, primary features, and functionality of the AP101S. The testing and development, which led to the integration of the processor are also detailed. Finally, the application of using it on-board the Space Shuttle Orbiter is portrayed. Indeed, the AP101S is an integral part of an aggressive and expanding Space Shuttle program, and is one which will serve well into the future.     

Visual evoked potential actuated brain computer interface: a brain-actuated cursor system

Flash visual evoked potential (FVEP), induced by OFF-to-ON flash, i.e. flash onset, in a light emitting diode (LED) was used to control four cursor movements (left, right, up, down), and left- and right-button clicks on a screen menu. ON or OFF duration in each flashing sequence was designed to be random so that all flashing sequences were mutually independent. Since FVEPs are time-locked and phase-locked to flash onsets of gazed LEDs, segmenting EEG signals based on the flash onsets of each flashing sequence followed by averaging will sharpen epochs evoked by gazed LEDs. Four inexperienced subjects were asked to generate a sequence of cursor commands. Mean recognition and transfer rates were 88% and 3.74 s/command, respectively.     

Asynchronous P300-based brain-computer interfaces: a computational approach with statistical models

Asynchronous control is an important issue for brain-computer interfaces (BCIs) working in real-life settings, where the machine should determine from brain signals not only the desired command but also when the user wants to input it. In this paper, we propose a novel computational approach for robust asynchronous control using electroencephalogram (EEG) and a P300-based oddball paradigm. In this approach, we first address the mathematical modeling of target P300, nontarget P300, and noncontrol signals, by using Gaussian distribution models in a support vector margin space. Furthermore, we derive a method to compute the likelihood of control state in a time window of EEG. Finally, we devise a recursive algorithm to detect control states in ongoing EEG for online application. We conducted experiments with four subjects to study both the asynchronous BCI's receiver operating characteristics and its performance in actual online tests. The results show that the BCI is able to achieve an averaged information transfer rate of approximately 20 b/min at a low false positive rate (one event per minute).     

运动控制系统接口模块设计

为一种微小型车辆和机器人的双处理器主从控制系统设计接口模块,控制系统以PC为上位机,DSP为下位机。该接口模块采用PCI总线通讯的方式,实现上位机和下位机之间的通讯,上位机和下位机配合完成对某小型履带式车多个自由度的控制和车体姿态信息采集的功能。文中选用总线接口芯片CH365完成接口模块电路的硬件设计,并且选择驱动模型WDM,介绍驱动开发软件和调试工具,对接口模块进行驱动开发,完成驱动程序的编写。     

Hybrid control system design using a fuzzy logic interface

A hybrid control system is proposed for regulating an unknown nonlinear plant. The interface between the continuous-state plant and the discrete-event supervisor is designed using a fuzzy logic approach. The fuzzy logic interface partitions the continuous-state space into a finite number of regions. In each region, the original unknown nonlinear plant is approximated by a fuzzy logic-based linear model, then state-feedback controllers are designed for each linear model. A high-level supervisor coordinates (mode switching) the set of closed-loop systems in a stable and safe manner. The stability of the system is studied using nonsmooth Lyapunov functions. For illustration and verification purposes, this technique has been applied to the well-known inverted pendulum balancing problem.     

HRPD空中接口技术(A版本)

HRPD(HighRatePacketData)空中接口标准(IS-856)是cdma2000标准家族的一员,该技术在高速数据传输方面进行了优化,能够很好地支持移动通信网络中各种类型的数据分组应用。其0版本的标准于2000年颁布,标志着高速数据业务的可实现化。而颁布不久的空中接口标准A版本(IS-856-A)则是弥补了0版本的诸多不足,既对每层协议都有相应的增强又新增了不少协议以提高性能。就HRPD空中接口标准A版本进行介绍,着重介绍其物理层和高层协议对新业务和服务质量(QoS)的支持。     

2000年IEEE国际可靠性物理年会论文集论文摘要(2)

202 W涂层对微型发动机性能的影响（Effectof W Coating on Microengine Performance)——2000International Reliability Physics Symposium pp. 146 -151.     

2000年IEEE国际可靠性物理年会论文集论文摘要(3)

231多分支线路电迁移寿命的提高（Electromigration　Lifetime Enhancement　for　LinesWith　Multiple　Branches）——2000 International　Re-liability Physics　Symposium pp.324-332.用时钟或电源互连“树”,通常有非常高的“主干”馈送电流到多个分支线路中。验证并讨论了通过在插孔金属系统中增加电流分路数量来提高“主干”的寿命。分支线路的作用就象附加Al和Cu离子的“水库”或来源,可重新填补部分空隙或减缓空隙的增长。文中指出,任何低电流密度的金属区都被看作较高电流密度区的金属离子的“库”或来源,可有效地延长较高电流密度区的寿命。文章确定了比较Black模型的参数,描述了失效分析。