Adaptive WTA With an Analog VLSI Neuromorphic Learning Chip

In this paper, we demonstrate how a particular spike-based learning rule (where exact temporal relations between input and output spikes of a spiking model neuron determine the changes of the synaptic weights) can be tuned to express rate-based classical Hebbian learning behavior (where the average input and output spike rates are sufficient to describe the synaptic changes). This shift in behavior is controlled by the input statistic and by a single time constant. The learning rule has been implemented in a neuromorphic very large scale integration (VLSI) chip as part of a neurally inspired spike signal image processing system. The latter is the result of the European Union research project Convolution AER Vision Architecture for Real-Time (CAVIAR). Since it is implemented as a spike-based learning rule (which is most convenient in the overall spike-based system), even if it is tuned to show rate behavior, no explicit long term average signals are computed on the chip. We show the rule's rate-based Hebbian learning ability in a classification task in both simulation and chip experiment, first with artificial stimuli and then with sensor input from the CAVIAR system     

Inter-spike-intervals analysis of AER Poisson-like generator hardware

Address–Event–Representation (AER) is a communication protocol for transferring images between chips, originally developed for bio-inspired image-processing systems. Such systems may consist of a complicated hierarchical structure with many chips that transmit images among them in real time, while performing some processing (for example, convolutions). In developing AER-based systems it is very convenient to have available some means of generating AER streams from on-computer stored images. Rank order coding (ROC) and Poisson rate coding are the extremes of spikes coding. In this paper, we present a pseudo-random hardware method for generating AER streams in real time from a sequence of images stored in a computer's memory. The Kolmogorov–Smirnov test has been applied to quantify that this method follows a Poisson distribution of the spikes. A USB–AER board, developed by our RTCAR group, have been used for the measurements. An example scenario of use under the EU CAVIAR project is presented.     

Object motion detection using information theoretic spatio-temporal saliency

This paper proposes to employ the visual saliency for moving object detection via direct analysis from videos. Object saliency is represented by an information saliency map (ISM), which is calculated from spatio-temporal volumes. Both spatial and temporal saliencies are calculated and a dynamic fusion method developed for combination. We use dimensionality reduction and kernel density estimation to develop an efficient information theoretic based procedure for constructing the ISM. The ISM is then used for detecting foreground objects. Three publicly available visual surveillance databases, namely CAVIAR, PETS and OTCBVS-BENCH are selected for evaluation. Experimental results show that the proposed method is robust for both fast and slow moving object detection under illumination changes. The average detection rates are 95.42% and 95.81% while the false detection rates are 2.06% and 2.40% in CAVIAR (INRIA entrance hall and shopping center) dataset and OTCBVS-BENCH database, respectively. The average processing speed is 6.6 fps with frame resolution 320×240 in a typical Pentium IV computer.     

一种错误敏感的词对齐评价方法

对齐错误率(Alignment Error Rate,AER)是目前通用的词对齐评价标准。近年来的研究表明,AER虽然在一定程度上能够反映词对齐的质量,但它与机器翻译最终结果BLEU得分的相关性并不好。该文针对基于短语的机器翻译系统(PBSMT)分析了AER可能存在的一些问题,并根据词对齐结果中存在的不同类型的错误,提出了一种错误敏感的词对齐评测方法ESAER(Error-Sensitive Alignment Error Rate)。实验表明,该文提出的ESAER与BLEU的相关性要远远好于AER。     

Citation analysis and impact factor trends in the Ergonomics Journal List, 1975–2007

The current study sought to investigate and analyze citation‐based trends in the field of human factors and ergonomics over a relatively long period of time. Journals were selected from the Ergonomics Journal List (EJL), originally formulated by Dul and Karwowski in 2004. Data were extracted from the Thomson Reuters Journal Citation Reports via a custom order in 2008. Various bibliometric indicators were examined and analyzed, including total citation counts, cited half‐lives, immediacy indices, and journal impact factors. Overall, the results suggest that, although citation counts have increased in recent years, trends were less clear regarding cited half‐lives and immediacy indices. Impact factors rose over time, however, with individual journals increasing their scores between 200% and 613%, with an overall increase of 416% for the EJL between 1975 and 2007. © 2009 Wiley Periodicals, Inc.     

Evaluation of a high‐volume,low‐latency market data processing system implemented with IBM middleware

A stock market data processing system that can handle high data volumes at low latencies is critical to market makers. Such systems play a critical role in algorithmic trading, risk analysis, market surveillance, and many other related areas. The current systems tend to use specialized software and custom processors. We show that such a system can be built with general‐purpose middleware and run on commodity hardware. The middleware we use is IBM System S which includes transport technology from IBM WebSphere MQ Low Latency Messaging (LLM). Our performance evaluation consists of two parts. First, we determined the effectiveness of each system optimization that the hardware and software infrastructure makes available. These optimizations were implemented at all software levels—application, middleware, and operating system. Second, we evaluated our system on different hardware platforms. Copyright © 2011 John Wiley & Sons, Ltd.     

Simultaneous monitoring of oxygen consumption and acidification rates of a single zebrafish embryo during embryonic development within a microfluidic device

A microfluidic device with a light modulation system was developed to simultaneously measure the oxygen consumption rate (OCR) and acid extrusion rate (AER) of a single zebrafish embryo during embryonic development. The device combines two components: an array of acrylic microwells containing two sensing layers as the dual luminescent sensor for oxygen (O₂) and acid (pH) detection, and a microfluidic module with pneumatically actuated glass lids to controllably seal the microwells. The continuous blue LED and modulated UV LED lights were simultaneously used to excite the dual luminescent sensor, with the emission detected by a single photodetector. The detection signals were then split into DC and AC components to measure the time variations in fluorescence intensity and phosphorescence lifetime for pH and O₂ detection, respectively. We have successfully measured the OCR and AER of a single developing zebrafish embryo inside a sealed microwell from the blastula stage (3 h post-fertilization, 3 hpf) through the hatching stage of 48 hpf. We also demonstrated the measurement of the OCR and AER of a single 48 hpf zebrafish that experienced acute hypoxia by using our device to monitor the transition between aerobic and anaerobic metabolism. We observed that the AER began to significantly increase, while the OCR rapidly decreased after 20 min of hypoxia, indicating the time point of transition where the non-mitochondrial metabolism subsequently dominated the energy production. Our proposed methodology provides the potential for studying the bioenergetic metabolism in a developing organism that relates mitochondrial physiology and disease.     

The experimental study of the Bi–Sn, Bi–Zn and Bi–Sn–Zn systems

The binary Bi–Sn was studied by means of SEM (Scanning Electron Microscopy)/EDS (Energy-Dispersive solid state Spectrometry), DTA (Differential Thermal Analysis)/DSC (Differential Scanning Calorimetry) and RT-XRD (Room Temperature X-Ray Diffraction) in order to clarify discrepancies concerning the Bi reported solubility in (Sn). It was found that (Sn) dissolves approximately 10 wt% of Bi at the eutectic temperature.

The experimental effort for the Bi–Zn system was limited to the investigation of the discrepancies concerning the solubility limit of Zn in (Bi) and the solubility of Bi in (Zn). Results indicate that the solubility of both elements in the respective solid solution is approximately 0.3 wt% at 200 C.

Three different features were studied within the Bi–Sn–Zn system. Although there are enough data to establish the liquid miscibility gap occurring in the phase diagram of binary Bi–Zn, no data could be found for the ternary. Samples belonging to the isopleths with w(Bi) 10% and w(Sn) 5%, 13% and 19% were measured by DTA/DSC. The aim was to characterize the miscibility gap in the liquid phase. Samples belonging to the isopleths with w(Sn) 40%, 58%, 77/81% and w(Zn) 12% were also measured by DTA/DSC to complement the study of Bi–Sn–Zn. Solubilities in the solid terminal solutions were determined by SEM/EDS. Samples were also analyzed by RT-XRD and HT-XRD (High Temperature X-Ray Diffraction) confirming the DTA/DSC results for solid state phase equilibria.     

A critical thermodynamic assessment of the Mg–Ni, Ni–Y binary and Mg–Ni–Y ternary systems

A thorough review and critical evaluation of phase equilibria and thermodynamic data for the phases in the Mg–Ni–Y ternary system have been carried out over the entire composition range from room temperature to above the liquidus. This system is being modeled for the first time using the modified quasichemical model which considers the presence of short range ordering in the liquid. The Gibbs energies of the different phases have been modeled, and optimized model parameters that reproduce all the experimental data simultaneously within experimental error limits have been obtained. For the liquid phases, the modified quasichemical model is applied. A sublattice model within the compound-energy formalism is used to take proper account of the structures of the binary intermediate solid solutions. The Mg–Ni and Ni–Y binary systems have been re-optimized based on the experimental phase equilibrium and thermodynamic data available in the literature. The optimized thermodynamic parameters for the Mg–Y system are taken from the previous thermodynamic assessment of the Mg–Cu–Y system by the same authors. The constructed database has been used to calculate liquidus projection, isothermal and vertical sections which are compared with the available experimental information on this system. The current calculations are in a good agreement with the experimental data reported in the literature.     

Construction of modified embedded atom method potentials for the study of the bulk phase behaviour in binary Pt–Rh, Pt–Pd, Pd–Rh and ternary Pt–Pd–Rh alloys

A first attempt is made to simulate the solid part of the phase diagram of the ternary Pt–Pd–Rh system. To this end, Monte Carlo (MC) simulations are combined with the Modified Embedded Atom Method (MEAM) and optimised parameters entirely based on Density Functional Theory (DFT) data. This MEAM potential is first validated by calculating the heat of mixing or the demixing phase boundary for the binary subsystems Pt–Rh, Pt–Pd and Pd–Rh. For the disordered alloy systems Pt–Rh and Pt–Pd, the MC/MEAM simulation results show a slightly exothermic heat of mixing, thereby contradicting any demixing behaviour, in agreement with other theoretical results. For the Pd–Rh system the experimentally observed demixing region is very well reproduced by the MC/MEAM simulations. The extrapolation of the MEAM potentials to ternary systems is next validated by comparing DFT calculations for the energy of formation of ordered Pt–Pd–Rh compounds with the corresponding MEAM energies. Finally, the validated potential is used for the calculation of the ternary phase diagram at 600 K.     

一个基于模拟退火的多主体模型及其应用

近些年,多主体系统的理论及应用得到了人们的广泛关注,并得以迅速发展.研究者提出了很多基于多主体系统理论的模型,用于求解各种问题.AER(Agent-environment-rules)模型正是一个用于求解约束满足问题较为成功的例子.但是,主体的静态策略选择在一定程度上限制了模型的求解性能.将模拟退火算法与多主体系统思想相结合,并赋予主体更为高效的动态策略选择的能力,提出了SAAER模型(simulated annealing based AER model).基于约束满足问题经典实例--N-Queen问题和染色问题的实验表明,改进后的模型较之原模型获得了更高的效率和稳定性.对于N=10000的大规模N-Queen问题,能在200s左右的时间求得精确解.     

On algorithmic rate-coded AER generation

This paper addresses the problem of converting a conventional video stream based on sequences of frames into the spike event-based representation known as the address-event-representation (AER). In this paper we concentrate on rate-coded AER. The problem is addressed as an algorithmic problem, in which different methods are proposed, implemented and tested through software algorithms. The proposed algorithms are comparatively evaluated according to different criteria. Emphasis is put on the potential of such algorithms for a) doing the frame-based to event-based representation in real time, and b) that the resulting event streams resemble as much as possible those generated naturally by rate-coded address-event VLSI chips, such as silicon AER retinae. It is found that simple and straightforward algorithms tend to have high potential for real time but produce event distributions that differ considerably from those obtained in AER VLSI chips. On the other hand, sophisticated algorithms that yield better event distributions are not efficient for real time operations. The methods based on linear-feedback-shift-register (LFSR) pseudorandom number generation is a good compromise, which is feasible for real time and yield reasonably well distributed events in time. Our software experiments, on a 1.6-GHz Pentium IV, show that at 50% AER bus load the proposed algorithms require between 0.011 and 1.14 ms per 8 bit-pixel per frame. One of the proposed LFSR methods is implemented in real time hardware using a prototyping board that includes a VirtexE 300 FPGA. The demonstration hardware is capable of transforming frames of 64/spl times/64 pixels of 8-bit depth at a frame rate of 25 frames per second, producing spike events at a peak rate of 10/sup 7/events per second.     

描述函数法在电力系统中的应用

本文提出用描述函数法来分析具有比例式励磁调节器（ＡＥＲ），电力系统稳定器（ＰＳＳ）和最优励磁控制方式等三种励磁控制方式对电力系统静稳定性能的影响，并进一步探讨各种励磁调节系统中的任一环节参数改变对电力系统静稳定鲁棒性的影响。运行结果表明，此法比经典法有更多的优越性。     

A parameter-extended case-based reasoning method based on a functional basis for automated experiential reasoning in mechanical product designs

The mechanical product design process involves much experiential reasoning which relies extensively on accumulated experience knowledge and ambiguous synthetic decision of experts (ASDE). This makes it hard to achieve the automated, intelligent and rapid design of mechanical products. Furthermore, due to the lack of consideration of experts' cognition of product functions and structures in the application of the current case-based reasoning (CBR) method in the field of automated experiential reasoning (AER), the parameter solving process is separated from ASDE. Aiming at improving the accuracy and intelligence level of AER in mechanical product design, this paper proposed a parameter-extended CBR (PECBR) method based on a functional basis by integrating ASDE into AER. The PECBR method mainly contains two parts: firstly, in order to acquire and quantitatively describe expert experiential knowledge to provide an effective basis for AER, a knowledge representation method integrating a function-flow-parameter matrix set (FFP-MS) using functional bases and a parameter experiential correlation matrix (PEC-M) extracted from FFP-MS were presented for mechanical products, where the FFP-MS characterized the operation of function and energy flow during the working process of products. An acquisition rule for FFP-MS was designed to extract the degree of correlation between each two parameters, in which the implicit knowledge hiding among functions, flows and parameters was mined to form PEC-M; secondly, to cope with the difficulty in integrating ASDE into AER, a feature-weighted case adaptation (FCA) method was proposed by adopting a presented weighted kernel support vector machine (WK-SVM) and dynamic particle swarm optimization (DPSO). The FCA method can achieve the intelligent and automated solving of product parameters through identifying PEC-M during the case adaptation process. Two case studies on two-stage reducers and corn huskers were carried out to demonstrate the validity of the PECBR method. Compared with other conventional CBR methods, PECBR method can derive a more accurate value of parameters in mechanical product designs especially in the case of limited similar cases.     

基于地址-事件表示的高速二值连通域标记方法

为提高二值连通域标记的速度,将地址-事件表示AER（Address Event Representation）思想引入到二值图像处理,提出了一种基于事件对等价标号的二值连通域标记方法。该算法无需多次遍历图像中的背景点和冗余目标点,首先将待标记的连通域以AER“事件对”的方式编码保存,通过“事件对”的遍历生成临时标号和等价标记表;然后根据等价表修改临时标号;完成标号映射后最终实现连通域标记。整个算法只处理极低冗余的事件信息,避免了对全图像素的重复扫描与处理。实验结果表明,图像以AER“事件对”方式存储,数据量仅为全帧图像的10%~35%,有较高的压缩比;且该算法速度快,可达到了传统基于等价标号算法的1.5~8倍。     

过程工业监测系统中的行为定制

讨论了在过程工业监测系统中行为定制机制的实现。通过行为定制机制,过程工业监测系统的用户可以为系统中的数据流事件、操作事件和定时事件定制响应行为脚本,在监测系统的固有功能之上自主地加入自己的数据处理功能。行为定制实现的基础是脚本技术和组件对象技术。行为定制机制要求监测系统为用户提供一组组件对象,用户可以在行为脚本中通过访问这些组件对象来访问生产数据,也可以在行为脚本中创建和使用其他应用系统提供的组件对象,获得其他应用系统的功能支持。     

Faster, better, cheaper-NASA visualizes the solar system

Pathfinder is the first of many planned “Discovery Program” missions by NASA. The Discovery program is based on the concept of using “industry spacecraft” comprised of near commodity components built from generic parts that cost orders of magnitude less than the custom built equipment of earlier phases of space exploration. Daniel Goldin, administrator of NASA, has given his agency a mandate to explore the solar system faster, better, and cheaper than in the past. How do you build an “industry spacecraft”? First, use as much COTS (commercial off the shelf) hardware and software as possible. That eliminates the need for NASA to build every part and write all the software. Instead of building a custom computer, at a cost of millions, now NASA finds a commercial system (on Pathfinder, an IBM RS6000) and modifies it as needed. And the computer will probably run some version of a commercial operating system, saving thousands or millions more dollars in development costs. Other COTS components include the Motorola modem used to communicate between the rover and lander, and the real time operating system used in the lander. Second, make everything as small and light as possible. Launch costs-the cost of a rocket and fuel-still account for 30 to 40 percent of the total cost of a mission. Every gram of weight shaved off a payload reduces the cost of launch or adds to the number of scientific instruments that can go on board. Image processing equipment and methods used in Pathfinder are discussed     

Visual-language system for user interfaces

The Universities of Pittsburgh and Salerno have jointly developed the Pittsburgh-Salerno Iconic System which lets users design, specify, and interpret custom visual languages for different applications. The system is still in the experimental stage, although we have used it in two practical applications. The experimental system lets interface developers create a custom visual language from sample visual sentences composed of custom or basic icons. The system has already been tested in two small applications, one involving a system for speech-impaired users     

自定制Nios处理器的FFT算法指令

本文深入研究了Nios自定制指令的软硬件接口,基于Altera的IP核FFTV2.2.0实现了变换长度为1024点的高速复数FFT算法,提出了一种在Nios嵌入式系统中定制用户FFT算法指令的方法。研究表明,将FFT算法加入到Nios嵌入式处理器指令集中,可以帮助系统完成复杂的数据处理任务,增强Nios系统的实时处理能力。     

DSOS—a skeletal,real–time,minicomputer operating system

This paper describes a skeletal operating system which provides the services and structure necessary to implement real-time applications. Features which would require a specific configuration or a non-minimal computer are either omitted or optional. In particular, although some protocol is established, no peripheral devices are required. System features include dynamic storage allocation, memory protection, multiprogramming, pseudo-clocks, and co-ordination and communication primitives. Due to its simple design, the system ‘kernel’ has proven to be remarkably error free.