探空莫尔斯码自动识别

介绍一种莫尔斯码自动识别系统的原理与实现。它由译码单片机和PC机组成,适用于气象探空及其他莫尔斯码通信设备。为了解决空间干扰及探空仪转速变化导致的码形长度变化和译码的模糊性问题,本文提出对探空仪发信周期测量值进行指数式加权平均,并采用一种专用的LMS自适应滤波器确定点码和划码的辨别阈值。为了降低误码率,文中还论及码形处理的几种方法,包括码形矫正、译码定时窗口及丢码填补。探空实验的结果说明这些方法行之有效。通过适当改动,这些方法同样可以应用于其他莫尔斯码系统。     

Unstable Morse code recognition with adaptive variable-ratio threshold prediction for physically disabled persons.

With one or two switches, Morse code could provide an effective alternative communication channel for individuals with physical limitations. However, most of the physically disabled persons have difficulties in maintaining a stable typing of Morse code, and hence the automated recognition of unstable Morse code is becoming more on demand. In this study, an adaptive variable-ratio threshold prediction (AVRTP) algorithm is proposed to analyze the Morse code time series with variable unit time period and ratio. Two least-mean-square (LMS) predictors are applied to track the dot interval and the dot-dash difference concurrently, and then a predicted threshold based on a variable-ratio decision rule is used to distinguish between dots and dashes. The same method is also applied to identify character-spaces. By the adaptive prediction of variable-ratio threshold, AVRTP has successfully overcome the difficulty of analyzing severely unstable Morse code time series and outperformed the previously proposed adaptive unstable-speed prediction (AUSP) algorithm and LMS and matching (I,MS&M) algorithm. This study concludes with a computer simulation and a preliminary clinical evaluation that demonstrate AVRTP as an efficient and reliable method for unstable Morse code recognition.     

Design of novel efficient adder and subtractor for quantum‐dot cellular automata

Quantum‐dot cellular automata (QCA) is one of the new emerging technologies being investigated as an alternative to complementary metal oxide semiconductor technology. This paper proposes optimized one‐bit full adder (FA) for implementation in QCA. The fault effects at the proposed FA outputs due to the missing cell defects are analyzed, and the test vectors for detection of all faults are identified. Also, the efficient designs of one‐bit full subtractor (FS), one‐bit FA/FS and four‐bit carry flow adder (CFA) are presented using the proposed FA. These structures are designed and simulated using QCADesigner software. The proposed designs are compared with other previous works. In comparison with the best previous design, the proposed FA has 25% and 26% improvement in cells count and area, respectively, and it is faster. For the proposed FS, FA/FS and CFA, the obtained results confirm that these designs are more efficient in terms of area, cell count and delay. Therefore, the implementation of these designs may lead to the efficient use of the calculative unit in various applications, which may be used as a basic building block of a general purpose nanoprocessor. Copyright © 2014 John Wiley & Sons, Ltd.     

Verification of the Mathematical Model and Numerical Investigation into the Thermal–Hydraulic Parameters of Fuel Assemblies Containing Microspherical Fuel Elements

The article presents the results from numerical investigations into the hydrodynamics and temperature field in the KLT-40S reactor’s fuel assembly (FA) in the case of using microspherical fuel elements as nuclear fuel. The simulated FA has the same overall dimensions as the existing FA containing fuel rods, due to which it can be accommodated in the reactor core without the need of modifying the reactor design. The specific feature of an FA with micro fuel elements (MF FA) is the need to set up radial flow of coolant through the bed of micro fuel elements, which is achieved by using distribution and collection headers. The numerical simulation was carried out using the ANSYS Fluent computer code. The mathematical model implemented in the code has been refined and verified against the experimental data obtained by the authors on a model experimental setup whose design is similar to that of the considered FA containing micro fuel elements. Radial flow of coolant through the pebble bed is arranged in the model installation. The numerical and experimental data on pressure loss and temperature distribution in the bed estimated at different values of coolant mass velocity mass are compared with each other. The design of an FA containing micro fuel elements for the KLT-40S reactor is proposed. It has been found that almost purely radial flow of coolant can be set up with the perforation parameters (cross-section coefficients) higher than those mentioned in the literature. The serviceability of such a fuel assembly is demonstrated. The distributions of temperature, excess pressure, and coolant velocity and current lines are obtained. The perforation parameters of jackets confining the bed of micro fuel elements are presented.     

Man-machine communications through brain-wave processing

The possibility of monitoring voluntarily produced changes in the electroencephalogram (EEG) of a subject and translating these changes into a set of commands to be issued to an external device was investigated. Subjects performed five distinct tasks under both eyes-open and eyes-closed conditions. A feature set consisting of the asymmetry ratios and the power values for each lead at four frequency bands-delta (0-3 Hz) theta (4-7 Hz), alpha (8-13 Hz), and beta (14-20 Hz)-was used to characterize the EEG. The feature sets created from an estimate of the spectral density of the EEG for each task were used to test classification accuracy among the various tasks using a Bayes quadratic classifier. The results show that it is possible to distinguish, to a high degree of accuracy, among the various mental tasks studied, using only the EEG.     

适应IIDG接入的就地型馈线自动化改进策略

随着逆变型分布式电源（IIDG）的渗透率不断提升,基于单向潮流设计的就地型馈线自动化（FA）可能无法应对IIDG接入的场景。针对这一问题,以目前应用较多的2种就地控制型FA模式,即电压-时间型以及电压-电流型FA为例,详细分析了IIDG接入对就地控制型FA各开关动作情况的影响。在此基础上,结合电流保护、电压序分量以及方向元件对FA系统进行改进,提出了适用于有源配电网的就地控制型FA方案。最后,搭建FA系统仿真模型进行验证。结果表明,该策略可有效缓解IIDG接入对出口断路器保护、无压分闸以及电压电流型开关过流检测的影响,提高有源配电网的故障处理水平。     

Modeling triplet spike-timing-dependent plasticity using memristive devices

Triplet-based spike-timing-dependent plasticity (TSTDP) is an advanced synaptic plasticity rule that results in improved learning capability compared to the conventional pair-based STDP (PSTDP). The TSTDP rule can reproduce the results of many electrophysiological experiments, where the PSTDP fails. This paper proposes a novel memristive circuit that implements the TSTDP rule. The proposed circuit is designed using three voltage (flux)-driven memristors. Simulation results demonstrate that our memristive circuit induces synaptic weight changes that arise due to the timing differences among pairs and triplets of spikes. The presented memristive design is an initial step toward developing asynchronous TSTDP learning architectures using memristive devices. These architectures may facilitate the implementation of advanced large-scale neuromorphic systems with applications in real-world engineering tasks such as pattern classification.     

基于RPR数字化变电站秒脉冲同步方案

针对IEC61850标准所定义的过程总线上采样值高精度同步要求,提出一种基于弹性分组环(RPR)双环的数字化变电站秒脉冲(PPS)同步方案。在该方案中,RPR节点分为主、从2种节点,主节点接入源秒脉冲,从节点负责恢复PPS输出。PPS上升沿采用以太网物理层编码中的保留控制字K28.6表示,以抢占式高优先级(无延迟抖动)在RPR双环上同时传输;并采用主节点预补偿方式消除传输延迟的影响。对PPS恢复方案的误差进行了分析,给出了现场可编程门阵列(FPGA)的设计方法,采用硬件描述语言Verilog HDL设计,并用Modelsim软件做了仿真验证。结果表明:基于RPR双环的PPS恢复精度可以达到纳秒级;该方案使数字化变电站的过程总线和时钟同步网络合并成为可能。     

Information transfer rate in a five-classes brain-computerinterface

The information transfer rate, given in bits per trial, is used as an evaluation measurement in a brain-computer interface (BCI). Three subjects performed four motor-imagery (left hand, right hand, foot, and tongue) and one mental-calculation task. Classification of the EEG patterns is based on band power estimates and hidden Markov models. We propose a method that combines the EEG patterns based on separability into subsets of two, three, four, and five mental tasks. The information transfer rates of the BCI systems comprised of these subsets are reported. The achieved information transfer rates vary from 0.42 to 0.81 bits per trial and reveal that the upper limit of different mental tasks for a BCI system is three. In each subject, different combinations of three tasks resulted in the best performance     

Utilizing gamma band to improve mental task based brain-computer interface design.

A common method for designing brain-computer Interface (BCI) is to use electroencephalogram (EEG) signals extracted during mental tasks. In these BCI designs, features from EEG such as power and asymmetry ratios from delta, theta, alpha, and beta bands have been used in classifying different mental tasks. In this paper, the performance of the mental task based BCI design is improved by using spectral power and asymmetry ratios from gamma (24-37 Hz) band in addition to the lower frequency bands. In the experimental study, EEG signals extracted during five mental tasks from four subjects were used. Elman neural network (ENN) trained by the resilient backpropagation algorithm was used to classify the power and asymmetry ratios from EEG into different combinations of two mental tasks. The results indicated that ((1) the classification performance and training time of the BCI design were improved through the use of additional gamma band features; (2) classification performances were nearly invariant to the number of ENN hidden units or feature extraction method.     

EEG-based synchronized brain-computer interfaces: a model for optimizing the number of mental tasks.

The information-transfer rate (ITR) is commonly used to assess the performance of brain-computer interfaces (BCIs). Various studies have shown that the optimal number of mental tasks to be used is fairly low, around 3 or 4. We propose an experimental validation as well as a formal approach to demonstrate and confirm that this optimum is user and BCI design dependent. Even if increasing the number of mental tasks to the optimum indeed leads to an increase of the ITR, the gain remains small. This might not justify the added complexity in terms of protocol design.     

基于单片机的飞行校验中导航信号的模拟实现

以飞行校验系统在地面检测中的需要,提出了一种航空信号的模拟实现方案。以Morse、Marker、PPS几种航空信号为例,首先分析了它们的类型与特点,然后在讨论了正弦波、方波、混合波产生原理的基础上,提出了基于单片机、符合相关航空协议标准、包含信号产生、D/A转换、放大、滤波及键盘控制、显示的硬件电路设计和相应的软件设计。经过验证,该设计的运行结果符合要求,能够为飞行校验系统的地面检测设备的开发、维护提供连续有效的仿真信号。     

基于ISI的智能照明系统设计

提出了一种基于LonWorks技术的智能照明系统设计方案,并利用MiniEVK工具对其进行了开发。该方案选用低压电力线作为传输介质,并以PL3120芯片为核心设计了智能节点,采用新推出的ISI技术组建了控制网络。测试结果表明,该系统通信可靠性高,互操作性好,组网灵活,能够满足智能照明系统的设计要求。     

Inner code assisted parallel concatenated single parity check codes

This paper proposes a novel coding scheme to improve the performance of multidimensional parallel concatenated single parity check (PCSPC) codes. The high error floor of PCSPC codes prevents clear turbo cliff to be seen in the bit‐error rate (BER) performance. Based on the product accumulate type‐I (PA‐I) coding scheme, which adds serially an accumulator to the existing PCSPC code structure, our coding scheme considers a wide range of rate‐1 recursive systematic convolutional (RSC) codes replacing the accumulator. The convergence behavior of the proposed iterative decoding is monitored and analyzed using an extrinsic information transfer (EXIT) chart. It has been revealed from the EXIT chart analysis that the proposed coding scheme has a lower convergence threshold than the PA‐I coding scheme, especially when using a lower code rate PCSPC code as the outer code. For the 2D PCSPC(3,2) code with the code rate 0.5, the proposed coding scheme has a convergence threshold of 0.47 dB, whereas the convergence threshold of the PA‐I coding scheme is 0.81 dB. The convergence threshold of the proposed coding scheme is closer to theoretical limit (0.28 dB away from the theoretical limit) than that of the PA‐I coding scheme (0.62 dB away). However, for PCSPC codes with a higher code rate, the performance improvement of the proposed coding scheme with respect to the PA‐I coding scheme becomes smaller. A series of simulations is carried out to investigate the performance of the proposed coding scheme, and the simulation results show that better performance is achieved by using the proposed coding scheme compared with the PA‐I coding scheme. The simulation results show good consistency with the convergence threshold obtained from the EXIT chart, as the difference is only within 0.34 dB in all the evaluated cases. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

A proposed application of an industrial DOS computer fordistribution substation monitoring and control

This paper presents the design and implementation of an intelligent controller intended for use in distribution substations to perform monitoring and control duties within the framework of distribution automation needs. The hardware of the developed controller is a DOS based industrial computer running on ECB-BUS. The application software handles all input/output tasks, data collection, manipulation and control design decisions with its flexible structure. This embedded controller measures bus voltage, transformer and feeder currents and calculates the real and reactive power, power factor, frequency, and total harmonic distortion of voltage and current. In addition to its local remote data acquisition and monitoring functions by means of console and SCADA outputs, the system, through its relay outputs, is capable of performing automation tasks such as integrated Volt/VAr control, overload and underfrequency detection and load shedding at the substation level. This reliable, high capacity and low cost system is completely programmable so that it can handle new requirements with new configurations easily     

Designing a bi-directional logic translator

The design of a bi-directional logic translator requires a clear understanding of the parameters of logic design: Boolean algebra, voltage transfer, fanout, time delay, and power dissipation. Also, it requires the use of tri-state logic and latches in control lines, and it introduces several of the many logic families used in an actual digital system. This design project is suitable for a course in digital electronics, and it can lead to further developments in a senior thesis or in a graduate-level project. The simplest translator design (CMOS to TTL) can be a homework project. The most complex (a silicon to gallium-arsenide translator) is a research grade project for a graduate student. Exact specifications are determined by the instructor     

A brief discussion of abbreviations [From the Editor]

Abbreviations are a wonderful invention. They help us to say a lot in a very little space. This was very important in the early development of wireless communication, where Morse code was the radio operator's character set. Long words and phrases required relatively long periods of time to be transmitted using this rather slow, narrow bandwidth communications method. To try to correct this problem, radio operators devised and borrowed from telegraph operators standard abbreviations such as the Q code to represent common phrases. For example, QTH referred to the radio operator's location, QRM was radio interference, and QSL meant please acknowledge receipt of this message.     

应用于民航空管的TPU莫尔斯译码器

介绍了一种应用于民航空管的气象探空仪TPU莫尔斯译码器的软硬件设计及实现。该译码器的主要功能有：接收计算机控制命令数据;录取探空仪从高空发回的温度、压强和湿度莫尔斯码信号并处理、换算、显示;接收数据采集器的三维绝对坐标并经相应算法处理得三维气压坐标;通过串口上传三维气压坐标数据到PC机。计算机通过Internet将相应TPU数据实时传到民航空管中心。     

Teaching introductory autonomous robotics with JavaScript simulations and actual robots

This paper describes a flexible method of teaching introductory robotics. Students program an autonomous mobile robot to complete a set of tasks of increasing complexity, including multirobot tracking. Two proximity detectors (1 b each) and a pair of photosensors (2 b each) provide six sensory inputs to logic circuits, which control two drive motors and two internal memory flip-flops. The robot brain is a digital logic circuit programmed by loading an AS CH code that specifies the logic circuit configuration, similar in approach to a field-programmable gate array. The logic circuit design evolves with task complexity. Two internal set/reset flip-flops can be used to design a finite-state machine to implement a memory. One novelty of the method is that students develop and test their logic circuits on a Web-based graphic simulation before downloading the code to an actual robot. The simulation is written in JavaScript to acquire sensor readings and control robot motors to interact with the environment in a flexible manner. The simulation is downloaded with the Web page and runs smoothly on the client's machine, eliminating the need for high-speed connections. The ASCII code producing successful simulation performance is downloaded to an actual robot through a printer port on a PC in the robot laboratory. A microcontroller on the actual robot interprets the ASCII code in the same manner as the simulation. Classroom experience indicates that evolving a robot brain is an effective teaching tool and students enjoy applying logic circuit design to program a robot.     

Integrated rate, power and cell control in cellular CDMA systems: an interference-balancing approach

In this paper, a novel combined rate, power and cell control scheme that minimizes transmit bit energy while gracefully implementing the congestion control is proposed and studied. The reverse link in a code division multiple access (CDMA) system with a high degree of traffic fluctuation temporally as well as spatially is considered. The proposed radio resource management scheme attempts to reduce the interference power variation among base station antennas that can exist in a real radio network. Transmission rates of those users in the congested (non-congested) cells are decreased (increased); hence, the proposed scheme is appropriate for delay-insensitive variable-bit-rate applications. Minimization of average transmit bit energy is achieved, subject to maintenance of individual target Eb/I0 for each user. Two algorithms, one directly minimizing the transmit bit energy, and the other doing so indirectly using the measured pilot power, are presented. It can be shown that both algorithms select the optimal base station if forward- and reverse-link gains are reciprocal; however, the latter gain is decentralized and uses only the local measurements and is amenable for practical implementation.