A multi-channel distributed DAQ for n-TPC

A new fast neutron spectrometer named n-TPC has been designed by LPRI(Key Laboratory of Particle Radiation Imaging, Ministry of Education) at Tsinghua University. The neutron energy spectrum can be calculated from the recoil angle and energy of the recoil proton detected by a 704-pad GEM-TPC. In beam tests at IHIP(Institute of Heavy Ion Physics, Peking University) in 2014, n-TPC performed better than 6%@6 Me V energy resolution and5‰ detection efficiency. To find the best working parameters(the component and proportion of the gas, the high voltage between each GEM layer, etc.) of the n-TPC and support its application in various conditions, a multichannel distributed DAQ has been designed to read out the signals from the 704 channels. With over 25 Ms/s sampling rate and 12 bit resolution for each channel, it can record the time and amplitude information as well as traditional DAQs in the TPC application domain. The main design objective of this distributed DAQ, however, is more flexible parameter modulation and operation. It can support the n-TPC without the limitation of the chassis and categorize signals arriving from the 704 channels at the same time by different events without event triggers.     

Adaptive data acquisition algorithm in Raman distributed temperature measurement system

The sampling rate of data acquisition card (DAQ) employed in Raman distributed temperature sensor (RDTS) system is set to be constant, which exceeds 100 MHz for a higher spatial resolution of 1 m. The acquired data need to be averaged tens of thousands times to improve the signal-to-noise ratio (SNR). High-speed DAQ and cumulative average algorithm put forward higher request to the hardware device and the stability of data transmission between DAQ and computer. In this paper we propose a new adaptive data acquisition algorithm to regulate the sampling rate automatically according to the changes of data. The theoretical simulation of this algorithm in RDTS is analyzed in detail. The results indicate that the amount of computation is reduced efficiently and the measurement time is decreased correspondingly.     

改进的对块零树编码压缩方法对超光谱数据压缩

提出了对块零树的预测二值标量量化压缩编码方法，给出了压缩比公式，并应用此压缩编码实现了对超细光谱数据的压缩，该压缩编码方法既具有小波零树压缩编码高压缩比和宜于实时实现的特点，同时具有编码，解码速度快和易于实时传输等优点，实验结果表明，改进的对块零树编码压缩（IBBZTC）方法在不传输剩余误差的情况下，达到190倍的压缩比时，峰值信噪比仍然在30dB以上，压缩性能优于KL变换－静止图像压缩（KLT－JPEG），小波变换－矢量量化（WT－VQ），小波变换一零树矢量量化（WT－ZTVQ）和对块零树编码压缩方法。     

Data acquisition and instrument control system for neutron spectrometers

A personal computer (PC)-based data acquisition and instrument control system has been developed for neutron spectrometers in Dhruva reactor hall and Guide Tube laboratory. Efforts have been made to make the system versatile so that it can be used for controlling various neutron spectrometers using single end-on detector in step scan mode. Commercially available PC add-on cards have been used for input-output and timer-counter operations. An interface card and DC motor driver card have been developed indigenously. Software for the system has been written in Visual C++ language using MS Windows operating system. This data acquisition and instrument control system is successfully controlling four spectrometers at Dhruva reactor.     

Consensus for second-order multi-agent systems with position sampled data

In this paper, the consensus problem with position sampled data for second-order multi-agent systems is investigated.The interaction topology among the agents is depicted by a directed graph. The full-order and reduced-order observers with position sampled data are proposed, by which two kinds of sampled data-based consensus protocols are constructed. With the provided sampled protocols, the consensus convergence analysis of a continuous-time multi-agent system is equivalently transformed into that of a discrete-time system. Then, by using matrix theory and a sampled control analysis method, some sufficient and necessary consensus conditions based on the coupling parameters, spectrum of the Laplacian matrix and sampling period are obtained. While the sampling period tends to zero, our established necessary and sufficient conditions are degenerated to the continuous-time protocol case, which are consistent with the existing result for the continuous-time case. Finally, the effectiveness of our established results is illustrated by a simple simulation example.     

Optimal switching policy for performance enhancement of distributed parameter systems based on event-driven control

This paper aims to improve the performance of a class of distributed parameter systems for the optimal switching of actuators and controllers based on event-driven control. It is assumed that in the available multiple actuators, only one actuator can receive the control signal and be activated over an unfixed time interval, and the other actuators keep dormant.After incorporating a state observer into the event generator, the event-driven control loop and the minimum inter-event time are ultimately bounded. Based on the event-driven state feedback control, the time intervals of unfixed length can be obtained. The optimal switching policy is based on finite horizon linear quadratic optimal control at the beginning of each time subinterval. A simulation example demonstrate the effectiveness of the proposed policy.     

分布式计算机软件数据整合平台设计

为实现当前经济市场中各应用软件的整合,提高我国各行业间个性化软件的开发能力,加强企业间的科学化系统软件设立,保证企业的高效运行,以及质量和系统维护能力;根据较为常用的分布式计算机系统,提出一种软件数据整合平台的设计;以商用软件整合平台设计为例,以开发模式、服务、技术结构、功能为研究方向,在企业正常运行时,可以实现业务系统功能开发以及门户单点登录,提高企业的个性化系统应用和经济效益;本文根据以上基本需求提出该功能软件平台进行设计,并在实际应用中分析出对于当前企业发展所提供的助力;结果显示,在当前经济发展状况下,有效地使用软件数据整合平台可以很大程度上提高企业的科学化管理和有效的资源分配,使企业在市场竞争中提高经济效益和社会效益。     

SPEX-1403拉曼光谱仪扫描控制和数据采集系统的研制

我们研制成用于 SPEX— 1 0 4 3拉曼谱仪的数据采集 /扫描控制系统。编制了运行在WINDOWS 3.1操作系统下的拉曼谱仪扫描和数据采集软件 ,由于采用了一些新方法 ,此系统不仅可以替代原有的 DM1 A,而且在功能上比原系统有所加强并易于使用     

加速器故障分析软件及其在CSNS应用

对加速器运行过程中出现的故障进行准确分析,可有效提升加速器的可靠性及运行效率。而对于一些快速故障过程,必须依赖故障发生时刻存储的高度时间相关和高分辨率的数据,才能进行准确分析。设计了一种用于加速器的故障分析软件,可用于对快速故障进行可靠分析。在中国散裂中子源加速器中进行了应用,该系统非常准确地分析了此前无法定位的大部分束流丢失过程。该故障分析具有一定的通用性,可应用到其它加速器装置。     

有源头靠中一种分布式虚拟传声器优化方法

有源降噪头靠系统中,远程虚拟传声器技术能够解决控制点处与误差传声器处降噪量不匹配的问题。在实际应用中,多通道虚拟传声器技术存在收敛速度慢和运算复杂度高等问题。针对这个问题,本文通过重新设计远程虚拟传声技术的离线优化过程,提出一种分布式远程虚拟传声器技术优化方法。该方法将虚拟次级通路矩阵作对角化限制,同时对观测传递函数矩阵进行联合寻优,以实现一种分布式的更新算法。有源降噪头靠实验结果表明,所提算法能够有效降低远程虚拟传声器技术算法的运算复杂度,并且提升了算法的收敛速度。     

用蒙特卡罗方法计算光通过薄层随机分布粒子的散射

本文利用蒙特卡罗方法计算准直光束通过薄层随机分布粒子散射的透射和反射光强,并和输运理论的扩散近似结果做了比较。当散射接近各向同性时两者符合良好。当散射明显地成为各向异性时,蒙特卡罗方法的结果是合理的,而输运理论的扩散近似失效。     

一种低成本线阵CCD驱动与数据采集处理系统的研究

探索了一种在低成本下实现线阵CCD输出信号快速采集以及与PC通信的方法。讨论了线阵CCD系统的整体结构及工作流程。采用VHDL语言编写了驱动程序,实现了CCD的正确工作。利用DSP实现了对下位CCD的控制,在控制程序中利用"乒乓原理"实现了线阵CCD的数据采集,并同时给PC快速上传数据。基于Visual C++6.0平台编写了PC机控制软件,实现了对硬件电路的控制和对CCD输出信号的分析处理。     

A novel distributed optic fiber transduser for landslides monitoring

Unstable slopes have been monitored since the beginning of the last century. Current electro-optic detection technology can achieve automatic monitoring remotely with high safety and includes such methods as time domain reflectometry, optical time domain reflectometry and Brillouin optical time domain reflectometry. However, these technologies cannot simultaneously meet the requirements of distributed sensing, high initial measurement accuracy, large sliding distance and high dynamic range. Based on the space frame theory of reinforced concrete beams, this study presents an innovative design for a distributed optic fiber sensor: a novel transduser with a bowknot. Using the optic fiber microbending loss mechanism and optical time domain reflectometry technology, bending and shear tests based on the combined fiber sensor are conducted, and the vertical displacement of midspan, optical fiber sliding distance and loss data under three different spans are collected. Feasibility study and economic analysis of the transduser used for landslide monitoring are also presented. The results show that the maximum sliding distance of our transduser is 21.8, 26.5 and 30.6 mm with corresponding initial accuracies of 1.2, 2.3 and 3.3 mm, and the dynamic ranges are 0-20.6, 0-23.2 and 0-27.3 mm. The cost of the transduser is economical at $0.15/m, which demonstrates promising economic application, high monitoring effectiveness and stability in monitoring civil works, such as slope, dam and tunnel construction and measurement.     

Improved control for distributed parameter systems with time-dependent spatial domains utilizing mobile sensor-actuator networks

A guidance policy for controller performance enhancement utilizing mobile sensor–actuator networks(MSANs) is proposed for a class of distributed parameter systems(DPSs), which are governed by diffusion partial differential equations(PDEs) with time-dependent spatial domains. Several sufficient conditions for controller performance enhancement are presented. First, the infinite dimensional operator theory is used to derive an abstract evolution equation of the systems under some rational assumptions on the operators, and a static output feedback controller is designed to control the spatial process. Then, based on Lyapunov stability arguments, guidance policies for collocated and non-collocated MSANs are provided to enhance the performance of the proposed controller, which show that the time-dependent characteristic of the spatial domains can significantly affect the design of the mobile scheme. Finally, a simulation example illustrates the effectiveness of the proposed policy.     

A dynamic macromodel for distributed parameter magnetic microactuators

This paper presents a reduced-order model to describe the mechanical behaviour of microbeam-based magnetic devices. The integration for magnetic force is calculated by dividing the microbeam into several segments, and the nonlinear equation set has been developed based on the magnetic circuit principle. In comparison with previous models, the present macromodel accounts for both the micro-magnetic-core reluctance and the coupling between the beam deflection and magnetic force. This macromodel is validated by comparing with the experimental results available in some papers and finite-element solutions.     

Leader-following formation control of multi-agent networks based on distributed observers

To investigate the leader-following formation control, in this paper we present the design problem of control protocols and distributed observers under which the agents can achieve and maintain the desired formation from any initial states, while the velocity converges to that of the virtual leader whose velocity cannot be measured by agents in real time. The two cases of switching topologies without communication delay and fixed topology with time-varying communication delay are both considered for multi-agent networks. By using the Lyapunov stability theory, the issue of stability is analysed for multi-agent systems with switching topologies. Then, by considering the time-varying communication delay, the sufficient condition is proposed for the multi-agent systems with fixed topology. Finally, two numerical examples are given to illustrate the effectiveness of the proposed leader-following formation control protocols.     

分布式光纤Bragg光栅波长校准方法

提出了一种利用标准参考光谱进行波长校准的方法。实验中利用由宽带光源和光纤可调谐滤波器组成的可调谐光源分别扫描了参考光谱和传感光栅的光谱。在参考通道,ITU标准参考模块的输出是具有固定波长的梳状光谱。利用高斯拟合算法计算出由标准参考透射谱峰值输出的对应的驱动电压,通过样条插值函数获得了滤波器输出波长与驱动电压的关系。计算光栅反射谱峰值对应的驱动电压,利用上面获得的滤波器输出波长与驱动电压的关系式可以计算出传感光栅的Bragg波长。实验结果表明,在较大的波长范围内实现了对多个传感光栅的波长校准,减小了由滤波器非线性输出造成的测量误差,具有较高的重复性。     

分布式风光互补智能发电站集中监测管理系统

为了解决分布在野外偏远地区的监测站供电和管理问题,利用风光互补发电的方法为系统提供电力,并将电能储存在蓄电池里,分别提供24V的直流和220V的交流电供负载使用。集中监测管理系统采用C/S架构设计,主要由电力监测站、集中监测中心和传输网络组成,电力监测站作为客户端负责采集太阳能电池板、风机和蓄电池的状态参数,通过GPRS网络与集中监测中心服务器建立的TCP/IP网络连接将采集到的信息按照规定的数据协议上传,服务器接收、处理、分析和显示来自各监测站的数据,并存储在数据库ACCESS2003里。实验结果表明,设计的系统能够远程有效监测发电功率、蓄电池劣化甄别、剩余电量、和发电站运行状态等信息,实现了分布式站点电力的集中管理。     

KT5C 托卡马克分布式高速数据采集系统

介绍了小型磁约束环装置KT5C 上利用校园高速局域网络, 低成本实现的分布式高速数据采集系统。当在不同位置的三个用户同时发送采集请求时, 该系统能在10 秒左右完成每个用户5 个通道的采样频率为5MHz采样长度为512kB 的数据采集。实现了远程多用户同时操作, 提高了大量实验数据的采集效率。     

Serverless distributed learning for smart grid analytics

The digitization, informatization, and intelligentization of physical systems require strong support from big data analysis. However, due to restrictions on data security and privacy and concerns about the cost of big data collection, transmission, and storage, it is difficult to do data aggregation in real-world power systems, which directly retards the effective implementation of smart grid analytics. Federated learning, an advanced distributed learning method proposed by Google, seems a promising solution to the above issues. Nevertheless, it relies on a server node to complete model aggregation and the framework is limited to scenarios where data are independent and identically distributed. Thus, we here propose a serverless distributed learning platform based on blockchain to solve the above two issues. In the proposed platform, the task of machine learning is performed according to smart contracts, and encrypted models are aggregated via a mechanism of knowledge distillation. Through this proposed method, a server node is no longer required and the learning ability is no longer limited to independent and identically distributed scenarios. Experiments on a public electrical grid dataset will verify the effectiveness of the proposed approach.