A numerical procedure to solve the multichannel Schrödinger eigenvalue problem

We discuss the numerical solution of eigenvalue problems for systems of (regular) coupled Schrödinger equations. Using a high order CPM (abbreviation for piecewise Constant (reference potential) Perturbation Method) in a shooting procedure, eigenvalues can be computed accurately. A generalization of the Prüfer method for scalar Sturm-Liouville problems makes the whole procedure more robust and allows us to specify the required eigenvalue by its index.     

Validity of decision mode analysis on an ROI determination problem in multichannel fNIRS data

Region of interest (ROI) determination is necessary when using functional near-infrared spectroscopy (fNIRS) data to detect brain activity. To extract ROIs from multiple fNIRS channels, we investigated the validity of applying decision mode analysis to the fNIRS dataset. This classifies a dataset into clusters with similar features. For each cluster, the dataset is decomposed into a mean vector and a linear combination of eigenvectors. Applying this to fNIRS signals, the mean vector can be used to represent change in hemoglobin (Hb), and the eigenvectors interpreted as a signal component constructing the arbitrary signal. Characterizing these vectors by correlating them with a theoretical model of brain function aids our understanding of where Hb changes occur and what type of Hb changes reflect brain activity in fNIRS data. Decision mode analysis of fNIRS data measured during viewing stereoscopic images identified ROIs around the right inferior frontal gyrus associated with attentional control, and frontal association area associated with decision on action and prediction. Our experimental results showed that information obtained from decision mode analysis can aid quantitative and qualitative ROI determination.     

适用于异构移动自组织网络的多信道广播算法

在异构移动自组织网络中,为满足多样的用户需求,提高网络容量,节点往往配备了多种信道。传统的广播机制(如洪泛、基于节点的连通支配集和信道向量等)往往采用基于节点的转发方式,即对节点所拥有的多个信道采取一视同仁的态度,在收到消息后将直接在其所有信道上进行转发,导致其无法充分利用各个信道的性能优势,以及在某些不必要信道上的冗余转发。为了充分发挥多信道网络的优势,降低冗余转发带来的开销,提出了一种基于信道的连通支配集构造机制,该机制采用了基于信道的转发方式,在选择转发节点的同时也将对转发信道进行选择,并以此为基础提出了适用于异构移动自组织网络的广播算法。仿真结果表明,与原有的基于连通支配集和信道向量的广播算法相比,文中的算法分别降低了64.15%和13.95%的广播开销,并且,与信道向量相比,网络吞吐量提升了14.1%。     

多通道AD转换器MAX1168及其与DSP系统适配性研究

MAX1168是一种16位的ADC，它具有8位输入通道，200kSPS的吞吐率。其特点是功率低，具有SPI／QSPI／MICROWIRE、DSP兼容的串行接口．能工作于多种软件可编程工作模式及电源管理模式，是目前体积最小的16位ADC。本文介绍了MAX1168的特性、工作模式，并在讨论其与DSP适配性的基础上给出了具体的接口实例．     

PXI多通道瞬态信号测试系统

采用 National Instruments(NI)公司高速示波器和定时模块,对石油行业中的电起爆/点火技术进行了实验研究,开发出一套火工品器件的瞬态时间特性测试系统。基于LabVIEW 高效的软件开发环境和强大功能以及 LabVIEWsignal Processing Toolset 丰富的信号处理函数,结合 PXI-5112和 PXI-6602硬件模块,成功有效地完成了电起爆/点火器件信号的瞬态时间特性的实验测试。     

The Superman problem

Given a polygonK contained in a polygonP, and a points lying outsideP, we present a (n logn) algorithm that finds the minimum number of edges, ofP that we want to retain in order to hidek froms. Furthermore, if the visibility polygon ofs givenK is unbounded, the algorithm is shown to run in linear time. This paper is dedicated to J. Siegel and J. Shuster.This work was supported by Friends of McGill Fellowship while T. Shemer was at McGill University.     

The mailbox problem

We propose and solve a synchronization problem called the mailbox problem, motivated by a particular type of interaction between a processor and an external device or between two threads. In this problem, a postman delivers letters to the mailbox of a home owner and uses a flag to signal a non-empty mailbox. The owner must remove all letters delivered to the mailbox and should not walk to the mailbox if it is empty. We present algorithms and an impossibility result for this problem.     

Parallel multichannel music source separation system

The Journal of Supercomputing - This paper presents a parallel low-latency multichannel source separation system designed to recover the original signals of the instruments that compound a...     

Using SEEK for multichannel pattern recognition

The author's work on computerized analysis of the 2-channel, 24-hr electrocardiogram has previously resulted in the development of multichannel signal processing systems that learn by observation. A new tool for implementing such algorithms is described: the pattern recognition language SEEK. Programs written in SEEK build a knowledge base containing treelike data structures, each of which stores acquired information about a particular multichannel waveform. Input data are interpreted by performing an efficient parallel evaluation of the structures in the knowledge base. The work is applicable to a wide variety of pattern recognition problems that arise in medical signal processing. The approach is illustrated with examples drawn from ECG analysis.     

The interval-merging problem

A closed interval is an ordered pair of real numbers [x, y], with x ? y. The interval [x, y] represents the set {i ∈ R∣x ? i ? y}. Given a set of closed intervals I={[a₁,b₁],[a₂,b₂],…,[a_k,b_k]}, the Interval-Merging Problem is to find a minimum-cardinality set of intervals M(I)={[x₁,y₁],[x₂,y₂],…,[x_j,y_j]}, j ? k, such that the real numbers represented by equal those represented by . In this paper, we show the problem can be solved in O(d log d) sequential time, and in O(log d) parallel time using O(d) processors on an EREW PRAM, where d is the number of the endpoints of I. Moreover, if the input is given as a set of sorted endpoints, then the problem can be solved in O(d) sequential time, and in O(log d) parallel time using O(d/log d) processors on an EREW PRAM.     

Microprocessor-based multichannel analyser developed using POLYFORTH

Specialized laboratory test equipment can be very expensive to acquire, and unusual requirements are not likely to be catered for in standard commercial instruments. A desktop computer configured to meet special requirements by custom software may be the solution. This article describes the role of FORTH in the development of a multichannel analyser for evaluating the performance of a low light level imaging detector for use in astronomy and space research.     

基于分布式Vega的多通道投影视景仿真方法

针对多通道投影视景仿真通道问帧不同步,以及视点、角色对象位姿不一致的问题,研究基于分布式vega数据插播技术的多通道投影视景仿真方法,解决通道间帧同步和视点一致性问题.实验表明该方法对于多通道投影视景仿真开发具有简单方便,通道间帧同步性能好,视点、角色对象位姿完全一致的特点.     

Restoration of multichannel microwave radiometric images

A constrained iterative image restoration method is applied to multichannel diffraction-limited imagery. This method is based on the Gerchberg-Papoulis algorithm utilizing incomplete information and partial constraints. The procedure is described using the orthogonal projection operators which project onto two prescribed subspaces iteratively. Its properties and limitations are presented. The effect of noise was investigated and a better understanding of the performance of the algorithm with noisy data has been achieved. The restoration scheme with the selection of appropriate constraints was applied to a practical problem. The 6.6, 10.7, 18, and 21 GHz satellite images obtained by the scanning multichannel microwave radiometer (SMMR), each having different spatial resolution, were restored to a common, high resolution (that of the 37 GHz channels) to demonstrate the effectiveness of the method. Both simulated data and real data were used in this study. The restored multichannel images may be utilized to retrieve rainfall distributions.