Hardware and software platform for real-time processing and visualization of echographic radiofrequency signals

In this paper the architecture of a hardware and software platform, for ultrasonic investigation is presented. The platform, used in conjunction with an analog front-end hardware for driving the ultrasonic transducers of any commercial echograph, having the radiofrequency echo signal access, make it possible to dispose of a powerful echographic system for experimenting any processing technique, also in a clinical environment in which real-time operation mode is an essential prerequisite. The platform transforms any echograph into a test-system for evaluating the diagnostic effectiveness of new investigation techniques. A particular user interface was designed in order to allow a real-time and simultaneous visualization of the results produced in the different stages of the chosen processing procedure. This is aimed at obtaining a better optimization of the processing algorithm. The most important platform aspect, which also constitutes the basic differentiation with respect to similar systems, is the direct processing of the radiofrequency echo signal, which is essential for a complete analysis of the particular ultrasound-media interaction phenomenon. The platform completely integrates the architecture of a personal computer (PC) giving rise to several benefits, such as the quick technological evolution in the PC field and an extreme degree of programmability for different applications. The PC also constitutes the user interface, as a flexible and intuitive visualization support, and performs some software signal processing, by custom algorithms and commercial libraries. The realized close synergy between hardware and software allows the acquisition and real-time processing of the echographic radiofrequency (RF) signal with fast data representation.     

A method for real-time deconvolution

Real-time deconvolution can be used as a powerful tool for the identification of linear systems in many areas. The availability of high-speed VLSI convolvers/correlators opens possibilities of dealing with this problem digitally. The application of the frequency-domain Van-Cittert closed form as a deconvolution filter which can be implemented with such devices is analyzed. The topics addressed include the choice of the optimum parameter values (scaling constant, and expansion coefficient) in relation to the deconvolution bandwidth, and hence, deconvolution accuracy. It has been found that this technique shows a low sensitivity to the expansion coefficient value, making any repetitive optimization process unnecessary     

一种层次化的太阳黑子快速自动识别方法

太阳黑子的观测与识别是太阳物理学的重要任务。通过对太阳黑子的观测与分析,太阳物理学者可以更准确地分析以及预测太阳活动。随着观测仪器的不断进步,太阳全日面图像数据量也在快速增长。为了快速、准确地进行太阳黑子的自动识别和标注,本文提出了一种两层的太阳黑子识别模型。第一层模型采用深度学习模型YOLO,并使用基于交并比的k均值算法优化YOLO的参数,最终的YOLO模型能够识别绝大多数较大黑子和黑子群,仅有极少数孤立的本影较小的黑子未能识别。为进一步提高这类小黑子的识别率,第二层模型采用AGAST特征检测算法专门识别遗漏的小黑子。在SDO/HMI太阳黑子数据集上的实验结果表明,应用本文的层次化模型,各种形态的太阳黑子均能被有效识别,且识别速率高,从而能够实现实时太阳黑子检测任务。     

A method for filling complex polymeric microfluidic devices and arrays

This paper describes an improved method for filling microfluidic structures with aqueous solutions. The method, channel outgas technique (COT), is based on a filling procedure carried out at reduced pressures. This procedure is compared with previously reported methods in which microfluidic channels are filled either by using capillary forces or by applying a pressure gradient at one or more empty reservoirs. The technique has proven to be > 90% effective in eliminating the formation of bubbles within microfluidic networks. It can be applied to many devices, including those containing PDMS-terminated channel features, a single channel inlet, and three-dimensional arrays.     

A quantitative method for Failure Mode and Effects Analysis

Failure Mode and Effects Analysis (FMEA) is commonly used for designing maintenance routines by analysing potential failures, predicting their effect and facilitating preventive action. It is used to make decisions on operational and capital expenditure. The literature has reported that despite its popularity, the FMEA method lacks transparency, repeatability and the ability to continuously improve maintenance routines. In this paper an enhancement to the FMEA method is proposed, which enables the probability of asset failure to be expressed as a function of explanatory variables, such as age, operating conditions or process measurements. The probability of failure and an estimate of the total costs can be used to determine maintenance routines. The procedure facilitates continuous improvement as the dataset builds up. The proposed method is illustrated through two datasets on failures. The first was based on an operating company exploiting a major gas field in the Netherlands. The second was retrieved from the public record and covers degradation occurrences of nuclear power plants in the United States.     

超声被动定位的一种新滤波方法

本文以距离几何学为基础，对超声被动定位提出了一种新的滤波方法，理论分析证明，利用这种方法，可以提高定位精度，本文还给出了数值的例子，说明如何使用这种新的滤波方法。     

液位计自动检测装置的研制

为实现液位计的自动控制与测量,应用机器视觉与伺服运动控制相结合的方法,通过CCD成像技术,采用精密光栅尺读数,并编制出液位的自动检测软件系统,实现了对液位计在0～2 000 mm的全量程范围内扩展不确定度优于0.2 mm(k =2)的精确测量.通过实验测量表明:系统自动控制可靠,具有良好的测量准确度.     

Microfluidic shear devices for quantitative analysis of cell adhesion

We describe the design, construction, and characterization of microfluidic devices for studying cell adhesion and cell mechanics. The method offers multiple advantages over previous approaches, including a wide range of distractive forces, high-throughput performance, simplicity in experimental setup and control, and potential for integration with other microanalytic modules. By manipulating the geometry and surface chemistry of the microdevices, we are able to vary the shear force and the biochemistry during an experiment. The dynamics of cell detachment under different conditions can be captured simultaneously using time-lapse videomicroscopy. We demonstrate assessment of cell adhesion to fibronectin-coated substrates as a function of the shear stress or fibronectin concentration in microchannels. Furthermore, a combined perfusion-shear device is designed to maintain cell viability for long-term culture as well as to introduce exogenous reagents for biochemical studies of cell adhesion regulation. In agreement with established literature, we show that fibroblasts cultured in the combined device reduced their adhesion strength to the substrate in response to epidermal growth factor stimulation.     

一种制冷机组能效定量评价方法

在冷水机组比选过程中,通常会优先选择能效高、变工况性能好的产品,但冷水机组的性能对价格的影响,难以定量评价.通过对逐时负荷和气象参数的研究和变工况条件下COP值的计算,得出不同品牌机组年运行费用差异,并折算成价格因素,将机组性能量化,用此方法,可方便不同品牌的冷水机组间进行比选.     

一种抑制卡尔曼滤波发散的实时数据处理方法

由于水声环境的复杂性和水声信道的时空变特性及水下航行载体的机动性,水声定位系统测量的弹道样点野值较多,平滑性差。介绍了一种野值的自动剔除和卡尔曼滤波递推处理方法,克服了滤波发散。文中选取距离D的倒数作为状态变量,使得1／D是近似线性变化的,此时量测方程的误差也近似是线性的,卡尔曼滤波器的表现是稳定的,并且是渐近无偏的。卡尔曼滤波的递推形式,滤波增益矩阵Kk的离线计算出,Qk和Rk值选取固定植,野值设定门限自动剔除,使滤波器收敛和稳定时间短,实现了对快速目标的跟踪和滤波输出,没有出现发散现象。该方法的特点是实时性好,对快速目标具有良好的跟踪能力,而且能达到工程上应用的精度要求。