Biosignal pattern recognition and interpretation systems. 3.Methods of classification

The following topics are discussed: Bayes/minimum distance classifiers; maximum likelihood classification estimation; k-nearest neighbor classification; entropy criteria; syntactic techniques; string matching; the Cocke-Younger-Kasami parsing algorithm; syntactic learning; finite-state automata; neural network classification techniques; learning vector quantization; cluster swapping; hierarchial clustering procedures     

Detecting intruders using time-series data by projection pattern of silhouette

This paper describes a method of detecting intruders by video image processing. There are some studies on detecting intruders in video image by analyzing difference-binary images and motion vectors. Because of the use of simple features such as size and motion vectors of changing regions, these methods are not fully able to reduce erroneous detection caused by other factors, such as small animals, swaying of trees, and changes in brightness. We propose a method of detecting intruders by time-series data on the projection pattern of the silhouette. In this method, changing regions in video images are extracted by the interframe differential technique and are transformed into projection patterns. Evaluation scores (a measure of similarity to a human silhouette) are calculated by flexible matching between observed patterns and the standard pattern. Discrimination processing is carried out in terms of a time-series score by tracking a target of each video frame. We have made experiments with a prototype and confirmed the effectiveness of this method. © 1997 Scripta Technica, Inc. Electr Eng Jpn 119(1): 62–73, 1997     

Recognition of partial discharge pattern of electrode voids by neural network

A back-propagation neural network model is used to identify electrode types involved in partial discharge (tree, IEC (b), CIGRE method I) and to estimate the shapes of the cylindrical electrode voids, based on the specific charge-phase characteristics of the different electrode types.     

用机械振动频响法诊断大型变压器绕组松动

开展变压器绕组及铁心监测及诊断方法的研究,及早发现变压器绕组松动,避免突发事故具有十分重要的意义.利用机械振动频响法,通过对变压器的箱壁振动信号的测试和分析,对上海武威变电站220 kV变压器的绕组松动进行了测试分析,提出了诊断变压器绕组松动的新方法.     

Fault‐tolerant control of distributed systems by information pattern reconfiguration

Given a fault‐tolerance strategy and a distributed control system, the set of recoverable faults depends on the information pattern that is implemented. This paper shows that fault‐tolerance can be achieved, when possible, by the reconfiguration of the information pattern. A necessary and sufficient recoverability condition is provided, and sub‐optimal solutions are developed for actuator and sensor faults under system reconfiguration. Copyright © 2014 John Wiley & Sons, Ltd.     

射频仿真目标回波的天线方向图调制方法

针对雷达制导射频半实物仿真试验系统目标回波模拟逼真度问题,分析了传统做法中未考虑雷达天线方向图的目标回波模拟方法的弊端。采取利用雷达天线方向图调制目标回波功率的方法,对仿真试验系统的回波功率控制算法进行改进,实现了更为真实的目标回波功率变化模拟。仿真结果证明,该方法有效解决了末制导雷达半实物仿真试验过程中,特别是在多目标的环境下频繁出现的副瓣跟踪问题,大大提高了射频半实物仿真系统仿真结果的可信度。     

Derivation of class load pattern by field test for temperature sensitivity analysis

This paper proposes systematic procedures to derive the load pattern of various customer classes in a utility company. The questionnaires are adopted to find the power consumption of key electrical appliances. The customer load information is obtained through intelligent equipment which records customers' electricity demand on a 15-minute interval basis throughout the year. Five hundred meters are installed on statistically selected samples from the various customer classes. By the proposed sampling theory, the customer load characteristics will be derived with a sufficient confidence level. Statistical analysis is then performed to find the typical load pattern of each customer class based on the power measurements of field tests. The temperature effect on the power consumption of each customer class is then solved by investigating the relationship between customer power consumption and the ambient temperature. The proposed procedure has been adopted by Taipower Company to determine the customer load pattern to provide valuable information for better distribution planning and to design better load management programs to enhance system operating efficiency.     

Short-term temperature effect on the HRMAS spectra of human brain tumor biopsies and their pattern recognition analysis

Object  

To investigate the effect of temperature (0 versus 37°C) in the high-resolution magic angle spinning spectroscopy (HRMAS) pattern of human brain tumor biopsies and its influence in recognition-based tumor type prediction. This proof-of-principle study addressed the bilateral discrimination between meningioma (MM) and glioblastoma multiforme (GBM) cases.     

马赫-曾德干涉检测地下电缆周界振动的分析与实验

为提高马赫-曾德干涉光纤传感技术应用于城市中低压地下电缆防外力破坏预警领域的工作效率,需理清干涉电压信号与其振动受力之间关系。首先文中理论分析了干涉电压与振动力之间关系,指出在外界环境一定时,干涉电压变化率只与振动力有关。在此基础上设计实验,研究在刚性水泥地表传播的振动波与干涉电压信号之间的关系,对比分析了振动波与干涉电压信号的传播和衰减规律。结果表明马赫-曾德干涉电压变化率峰值与振动力大小呈正对应关系,可以用电压变化率峰值大小作为特征值来预判入侵外力距离地下电缆的远近或强弱。     

A model of the pacemaking neuron of the respiratory central pattern generator.

We have developed a model of the mammalian respiratory central pattern generator (rCPG) to mimic the salient characteristics of its constituent medullary neurons. This model is designed as a network of Hodgkin-Huxley-type medullary neurons driven by a pacemaking neuron from the pre-B?tzinger complex. Here, we present the results of our model of this pacemaking neuron, based on available voltage clamp data. Implications for the behavior of the rCPG are discussed.     

A predictive fatigue model. I. Predicting the effect of stimulation frequency and pattern on fatigue

Previously we developed a mathematical force- and fatigue-model system that could predict fatigue produced by a wide range of frequencies and pulse patterns. However, the models tended to overestimate the forces produced by higher frequency trains. This paper presents modifications to our previously developed force- and fatigue-model system to improve the accuracy in predicting forces during repetitive activation of human skeletal muscle. By comparing the predictions produced by the modified force and fatigue models to those by our previous models, the modification appears to be successful. The current force- and fatigue-model system accounts for about 93% variance in experimental data produced by fatigue protocols consisting of trains with a wide range of frequencies and pulse patterns. In addition, the present models successfully predict the effect of stimulation frequency and pulse pattern on muscle fatigue. The success of our current force- and fatigue-model system suggests its potential use in helping to identify the optimal activation pattern to use during the clinical application of functional electrical stimulation.     

箱型双向流道轴流泵装置内部流动的数值模拟和试验研究

箱型双向流道泵装置结构简单,实用性好,然而传统的箱型双向流道泵装置存在泵装置效率较低、进水流道内易产生水下漩涡的问题,导致机组振动,危害运行安全。针对此类问题提出新型曲线扩散出水结构和进水导流墩设计方案,用于箱型双向流道泵站的更新改造。通过箱型双向流道泵装置内流场的数值模拟计算,分析了流动规律,获得了泵装置外特性曲线。同时在标准模型水泵试验台上进行了模型的性能试验,并与计算的性能曲线进行了比较,二者在高效区较为接近,说明计算可信。新的设计方案提高了泵装置效率,消除了水下漩涡,可以有效地保证泵机组运行的经济性和安全性。     

Partial discharge pattern recognition by neuro-fuzzy networks in heat-shrinkable joints and terminations of XLPE insulated distribution cables

An identification technique is described, based on a developed adaptive fuzzy logic network, that enables the recognition of partial discharges (PD) generated by different defects in heat-shrinkable joints and terminations of XLPE insulated power distribution cables. It is shown that different sources of PD can be identified on the basis of fuzzy rules applied to a selection of parameters derived from PD-pulse phase and amplitude distributions. A comparison with other PD pattern recognition techniques based on traditional neural networks is presented and discussed.     

Position only pattern nulling of linear antenna array by using a clonal selection algorithm (CLONALG)

In this paper, a clonal selection algorithm (CLONALG) based on clonal selection principle of immune system has been used for null steering in the antenna radiation pattern by controlling only the element positions of a linear array. Numerical examples of Chebyshev pattern with the single, multiple and broad nulls imposed at the directions of interference are given to show the accuracy and flexibility of the CLONALG. The sensitivity of the achieved patterns due to small variations of the element positions is also investigated by truncating the element positions.     

Event‐related potentials affected by spatial frequencies of background visual pattern during a cognitive task

Spatial variation in luminance, which is one of the most important attributes of a visual image, may cause characteristic reactions in higher order brain functions. We aim to characterize the event‐related potentials (ERPs) associated with a cognitive task (simple addition) in terms of how they are influenced by the spatial frequencies of the background visual pattern. We use vertically striped visual stimuli with embedded numbers (0–9) and different spatial frequency characteristics (white noise, 1/f, 1/f², and 1/f³). The subjects are instructed to perform two tasks: an addition task that involved adding numbers presented as visual stimuli, and a reference task wherein the numbers were not added. In ERPs averaged over four types of visual stimuli for the addition task, positive components peaking at latencies of 182 ms in the central and frontal areas and 360 ms in the parietal area are observed, and significant differences are found between ERPs for the addition and reference tasks. In the addition task, the 182‐ms latency component shows a larger positive amplitude for 1/f³ compared with other stimuli in the right parietal‐occipital‐temporal area (P₄, T₆, O₂), and the 360‐ms latency component tends to show a larger positive amplitude for 1/f compared with other stimuli in the parietal‐central area (C₃, P₃, P_z). We conclude that spatial frequency characteristics influence ERPs associated with the retrieval of arithmetic data and certain neural activities that accompany simple forms of addition. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Minimization of spectral pattern changes during HRMAS experiments at 37 degrees celsius by prior focused microwave irradiation

Object

High-resolution magic angle spinning (HRMAS) magnetic resonance spectroscopy provides detailed metabolomic information from intact tissue. However, long acquisition times and high rotation speed may lead to time-dependent spectral pattern changes, which may affect proper interpretation of results. We report a strategy to minimize those changes, even at physiological recording temperature.

Materials and methods

Glioblastoma (Gbm) tumours were induced in 12 mice by stereotactic injection of GL261 cells. Animals were sacrificed and tumours were removed and stored in liquid N₂. Half of the samples were exposed to focused microwave (FMW) irradiation prior to HRMAS while the other half was not. Time-course experiments (374?min at 37°C, 9.4T, 3,000?Hz spinning rate) were carried out to monitor spectral pattern changes. Differences were assessed with Unianova test while post-HRMAS histopathology analysis was performed to assess tissue integrity.

Results

Significant changes (up to 1.7 fold) were observed in samples without FMW irradiation in several spectral regions e.g. mobile lipids/lactate (0.90–1.30?ppm), acetate (1.90?ppm), N-acetyl aspartate (2.00?ppm), and Choline-containing compounds (3.19–3.25?ppm). No significant changes in the spectral pattern of FMW-irradiated samples were recorded.

Conclusion

We describe here a successful strategy to minimize spectral pattern changes in mouse Gbm samples using a FMW irradiation system.     

计及直流偏磁的保护用电流互感器仿真与实验分析

保护用电流互感器(Current Transformer,CT)对电力系统继电保护的动作特性影响很大。直流偏磁会对CT的传变特性产生影响,利用其T型等值电路推导出了直流偏磁条件下的励磁电流和磁通的表达式。通过PSCAD/EMTDC仿真软件对不同直流偏移系数条件下的CT传变特性进行仿真分析,结果表明,偏磁条件下CT的磁化曲线第三象限部分会减小,二次电流波形也会发生畸变,同时二次电流中谐波幅值也在增加,当偏磁电流增加到一定值时二次谐波将会大于三次谐波,随着直流偏移系数的增加各次谐波也呈线性增长,而基波幅值在减小。同时,设计了交流叠加直流的实验电路来模拟直流偏磁现象以对保护用CT的传变特性进行实验分析。实验结果表明,在偏磁条件下CT不能正确传变一次电流,在偏磁条件下CT二次电流有效值会减小,同时基波幅值也相应减小,而其余各次谐波的幅值呈线性增加,对角差的影响较电流误差而言更为严重。由此可见,直流偏磁改变了保护用CT的传变特性,对采用基波分量算法及谐波制动方案类型的保护构成严重威胁,降低继电保护的可靠性。     

带横缝拱坝地震破坏机理的振动台试验研究

本文通过脆性材料制作的带横缝拱坝模型,采用逐步加大的谐波荷载,考察拱坝的动力破坏机理.通过对模型拱坝整个破坏过程的观测,重点研究不同破坏阶段模型拱坝在动力荷载作用下的一些反应规律.同时,结合试验模型坝体的破坏历程.对拱坝计算专用有限元程序ADADP-88的合理性做进一步验证,为工程实际的破坏计算预估莫定基础.