基于Mask R-CNN的试管-支架系统Data Matrix码识别方法

在试管-支架自动化系统的输入图像中,Data Matrix(DM)码呈现为多个小目标,图像存在成像模糊、边缘干扰严重等问题,使得传统方法难以达到良好的识别效果。为此,提出一种基于深度学习的Data Matrix码识别方法DeepDMCode,以Mask R-CNN模型为基础,通过内容差异化数据合成和同步自动化标注,实现训练数据的增强,提升模型的学习能力。在模型分割结果的基础上,提出一种旋转校正方法,确保可用标准解码库实现DM码的解码。以分辨率为1600×1200、支架容量为96的数据实验表明,由于该方法在前期码定位阶段最大程度地还原码边界信息,准确度可达0.92(mIoU),完成单张图像中所有DM识别的平均速度为5.2 s,优于YOLO、SegNet、CenterNet等主流工业基准算法。

移动PI-HMIPv6快速切换技术及仿真分析

本文主要探究了移动PI-HMIPv6快速切换技术的基本原理和运行流程。采用对照试验方法,使用网络仿真器NS-2软件搭建仿真环境,设定好仿真参数后,对比了MIPv6、HMIPv6和PI-HMIPv6三种协议下移动节点的切换时延。仿真结果表明,移动节点无论是在域内切换还是在域间切换,PI-HMIPv6的切换时延均维持在300~500 ms之间,明显低于MIPv6和HMIPv6。由此可得,移动PI-HMIPv6快速切换技术能够将切换时延维持在较低水平,满足了通信业务的实时性要求。

Real-time crash prediction on freeways using data mining and emerging techniques

Recent advances in intelligent transportation system allow traffic safety studies to extend from historic data-based analyses to real-time applications. The study presents a new method to predict crash likelihood with traffic data collected by discrete loop detectors as well as the web-crawl weather data. Matched case-control method and support vector machines （SVMs） technique were employed to identify the risk status. The adaptive synthetic over-sampling technique was applied to solve the imbalanced dataset issues. Random forest technique was applied to select the contributing factors and avoid the over-fitting issues. The results indicate that the SVMs classifier could successfully classify 76.32% of the crashes on the test dataset and 87.52% of the crashes on the overall dataset, which were relatively satisfactory compared with the results of the previous studies. Compared with the SVMs classifier without the data, the SVMs classifier with the web-crawl weather data increased the crash prediction accuracy by 1.32% and decreased the false alarm rate by 1.72%, showing the potential value of the massive web weather data. Mean impact value method was employed to evaluate the variable effects, and the results are identical with the results of most of previous studies. The emerging technique based on the discrete traffic data and web weather data proves to be more applicable on real- time safety management on freeways.

Quantifying urbanization levels on the Tibetan Plateau with high-resolution nighttime light data

The Tibetan Plateau(TP)is undergoing rapid urbanization.To improve urban sustainability and construct eco-logical security barriers,it is essential to quantify the spatial patterns of urbanization level on the TP,but the existing studies on the topic have been limited by the lack of socioeconomic data.This study aims to quantify the urbanization level on the TP in 2018 with Luojia1-01(LJ1-01)high-resolution nighttime light(NTL)data.Specifically,the compounded night light index is used to quantify spatial patterns of urbanization level at mul-tiple scales.The results showed that the TP had a low overall urbanization level with a large internal difference.The urbanization level in the northeast,southeast and south of the TP was relatively high,forming three hotspots centered in Xining City,Lhasa City and Shangri-La City,while the urbanization level in the central and western regions was relatively low.The analysis of influencing factors,based on the random forest model,showed that transportation and topography were the main factors affecting the TP’s spatial patterns of urbanization level.The comparison analysis with socioeconomic statistics and traditional NTL data showed that LJ1-01 NTL data can be used to more effectively quantify the urbanization level since it is more advantageous for reflecting the spatial extent of urban land and describing the spatial structure of socioeconomic activities within urban areas.These advantages are attributed to the high spatial resolution of the data,appropriate imaging time and unaf-fected by saturation phenomena.Thus,the proposed LJ1-01 NTL-based urbanization level measurement method has the potential for wide applications around the world,especially in less-developed regions lacking statistical data.Using this method,we refined the measurement of the TP’s urbanization level in 2018 for multiple scales including the region,basin,prefecture and county levels,which provides basic information for the further urban sustainability research on the TP.

High-speed broadband data acquisition system based on FPGA

A field-programmable gate array(FPGA)based high-speed broadband data acquisition system is designed.The system has a dual channel simultaneous acquisition function.The maximum sampling rate is 500 MSa/s and bandwidth is200 MHz,which solves the large bandwidth,high-speed signal acquisition and processing problems.At present,the data acquisition system is successfully used in broadband receiver test systems.

An Approach of Tropospheric Correction for VLBI Phase-Referencing using GPS Data

The dominant source of error in VLBI phase-referencing is the troposphere at observing frequencies above 5 GHz. We compare the tropospheric zenith delays derived from VLBI and GPS data at VLBA stations collocated with GPS antennas. The systematic biases and standard deviations both are at the level of sub-centimeter. Based on this agreement, we suggest a new method of tropospheric correction in phase-referencing using combined VLBI and GPS data.

On the Influence Factors of Second-hand House Prices in First-tier Cities——Empirical Analysis Based on Panel Data

With the arrival of the ＂housing stock＂ in first - tier cities, the second - handhousing^market will become the dominant property market. This ardcle aim to the first - tiercities of second - hand housing prices and new home price index for the empirical analysis, thedata related to the cointegration analysis found that the result of the first -tier cities real estatemarket in China, the new home price index is the significant factors influencing the second -hand house price indexi For Beijing, Shanghai second - hand housing and new home price in-dex time series johans test, found that there exists cointegration relationship between two varia-bles,the new city real estate market prices out of a line on the secondary market have clearguide. Therefore, the real estate market regulation aiming at the first -tier cities and the＂housing stock＂ should take the second - hand housing market as the main direction, startingwith the sale price and influencing factors of new houses. At the same time, in different cities,we should adhere to the city＇ s policies, reflect the policy differentiation, promote the reformof the real estate supply side, and promote the return of housing properties.

Comparison between Google Earth KML Data and RTK Data on a Flight Planning Simulated to the Unmanned Aerial Vehicle Microdrone MD4-1000

The UAVs （unmanned aerial vehicles） and the use of graphical data files of extension KML （keyhole markup language） have become popular nowadays. The KML files are associated to the Google Earth applications. Developed by Microdrone company for planning, overflight simulation and data flight analysis, the program mdCockpit was used in this experiment. The UAV Microdrone＇s flight path was programmed in two ways： using geo referenced images from Google Earth and entering points coordinates into the program. These points have had their geographical decimal coordinates collected by GPS （global positioning system） （RTK （real time kinematic）） method. The aim here is to describe a way of evaluating the difference between the alternatives of flight planning. A flight path, defined a route with 22 points, was also simulated in the program mdCockpit. The points were collected and saved, while the images captured by the program went automatically forming a georeferenced mosaic. A comparison between the differences of coordinates to each point was made by choosing on the images and also by a RTK positioning. The result was up to 14.20 m to a 100 m flight height. There is a significant change of position and this can result in unwanted over flights in locations or even jeopardizing the safety of air activity.

On the non-Gaussian errors in high-z supernovae type Ia data

The nature of random errors in any data set is Gaussian, which is a well established fact according to the Central Limit Theorem. Supernovae type Ia data have played a crucial role in major discoveries in cosmology. Unlike in laboratory experiments, astronomical measurements cannot be performed in controlled situations. Thus, errors in astronomical data can be more severe in terms of systematics and non-Gaussianity compared to those of laboratory experiments. In this paper, we use the Kolmogorov-Smiruov statistic to test non-Gaussianity in high-z supernovae data. We apply this statistic to four data sets, i.e., Gold data （2004）, Gold data （2007）, the Union2 catalog and the Union2.1 data set for our analysis. Our results show that in all four data sets the errors are consistent with a Gaussian distribution.

Correcting the Contamination of Second-order Spectra:Improving HαMeasurements in Reverberation Mapping Campaigns

Long-term spectroscopic monitoring campaigns on active galactic nuclei(AGNs)provide a wealth of information about its interior structure and kinematics.However,a number of the observations suffer from the contamination of second-order spectra(SOS)which will introduce some undesirable uncertainties at the red side of the spectra.In this paper,we test the effect of SOS and propose a method to correct it in the time domain spectroscopic data using the simultaneously observed comparison stars.Based on the reverberation mapping(RM)data of NGC 5548 in2019,one of the most intensively monitored AGNs by the Lijiang 2.4 m telescope,we find that the scientific object,comparison star,and spectrophotometric standard star can jointly introduce up to~30%SOS for Grism 14.This irregular but smooth SOS significantly affects the flux density and profile of the emission line,while having little effect on the light curve.After applying our method to each spectrum,we find that the SOS can be corrected effectively.The deviation between corrected and intrinsic spectra is~2%,and the impact of SOS on time lag is very minor.This method makes it possible to obtain the HαRM measurements from archival data provided that the spectral shape of the AGN under investigation does not have a large change.

X-Ray Properties of PSR J1811-1925 by Nu STAR

We analyzed the spectral properties and pulse profile of PSR J1811-1925,a pulsar located in the center of composite supernova remnant(SNR)G11.2-0.3,by using high timing resolution archival data from the Nuclear Spectroscopic Telescope Array Mission(NuSTAR).Analysis of archival Chandra data over different regions rules out the SNR shell as the site of the hard X-ray emission while spectral analysis indicates that the NuSTAR photons originate in the pulsar and its nebula.The pulse profile exhibits a broad single peak up to 35 keV.The jointed spectrum by combining NuSTAR and Chandra can be well fitted by a power-law model with a photon index ofΓ=1.58±0.04.The integrated flux of jointed spectrum over 1-10 keV is 3.36×10^(-12)erg cm^(-2)s^(-1).The spectrum of pulsar having photon indexΓ=1.33±0.06 and a 1-10 keV flux of 0.91×10^(-12)erg cm^(-2)s^(-1).We also performed the phase-resolved spectral analysis by splitting the whole pulse-on phase into five phase bins.The photon indices of the bins are all around 1.4,indicating that the photon index does not evolve with the phase.

数字地名研究综述

数字地名是地名服务信息化,包括地名地址的采集提取、处理建库、成果转化、地址匹配、数据可视化、数据共享与应用等内容。作者认为数学模型和人工智能方法提取地形图、卫星影像上的地名是地名地址数据自动采集的主要方法。城市地标的识别提取、中文信息和空间定位位置的识别相对较易,语义层面的深层次地址实体识别还存在问题,地址解析方法有待完善,大数据和人工智能技术是其解决之道。非地标地物地址、空间分布不连续地址的提取方法有待研究。建立快速的地名地址数据交换标准是一个迫切问题。在地址匹配方面,分词统计、人工智能等是主要方法,但都有局限性,地址分级越多,匹配效果越好。外层空间的地名命名需要与我国航天事业的发展同步甚至更快一步。每种少数民族语言的译音规则都是需要的,G20及金砖国家、一带一路沿线国家的地名汉字译写导则有待加强。地名分类有交叉,地址尚无较为科学的分类方法。中国地名文化遗产和一带一路地名文化是地名文化研究的热点,现代地名文化内涵需要进一步重视,历史地名保护及地名的古为今用仍任重道远。完善的地名地址标识辅以商用导航软件,寻址问路难题得到了根本解决。

DL/T645-2007《多功能电能表通信协议》的技术特点和创新

介绍了DL/T 645-2007《多功能电能表通信协议》制订中考虑的主要问题,以及《多功能电能表通信协议》各部分主要变化和技术创新,同时讨论了兼容问题的对策。

高性能LS-DSP的逻辑设计与低功耗设计

LS-DSP是面向数据密集型和控制密集型处理应用的需要,而开发的高性能数字信号处理器。本文主要介绍LS-DSP内有特点的逻辑设计技和低功耗设计技术。LS-DSP采用0.18ΜMCMOS工艺制造,集成度为1000万器件,芯片面积5×5MM2,主频为120MHZ,典型应用的平均动态功耗为325.084MW。

地名地址数据增量更新的质量控制

研究了地名地址数据的增量更新流程和特点,针对地名地址数据变化迅速、数据海量且属性繁杂的情况,以“天地图·广东”数据更新和广东省地名地址库建设项目生产过程中遇到的数据质量问题和易错点为切入点,探讨了地名地址数据增量更新的质量控制方式,旨在提高数据更新的成果质量和生产效率,同时促进技术设计和生产流程的优化。同时,通过该研究为类似的地理空间数据增量更新提供质量控制的参考。

VHF机载电台ACARS功能激活方法的研究

飞机通信寻址与报告系统(ACARS,aircraft communication addressing and reporting system)是目前世界范围内使用最广泛的空地数据链通信系统。以激活真实航材的ACARS功能为目的,选择典型的甚高频(VHF,very high frequency)机载电台柯林斯VHF-2100型,从接口规范、数据交互时序关系和电气连接特性3个方面进行研究,设计了ACARS功能的激活方法。通过实验平台的验证,测试结果表明:所设计的方法能够对VHF-2100机载电台进行配置,并能使其收发ACARS报文。真实航材的激活验证了接口控制的可行性,对ACARS机载电台的国产化有一定的借鉴意义。

x86处理器向量条件访存指令安全脆弱性分析

单指令多数据流(Single Instruction stream,Multiple Data streams,SIMD)是一种利用数据级并行提高处理器性能的技术,旨在利用多个处理器并行执行同一条指令增加数据处理的吞吐量.随着大数据、人工智能等技术的兴起,人们对数据并行化处理的需求不断提高,这使得SIMD技术愈发重要.为了支持SIMD技术,Intel和AMD等x86处理器厂商从1996年开始在其处理器中陆续引入了MMX(MultiMedia Extensions)、SSE(Streaming SIMD Extensions)、AVX(Advanced Vector eXtensions)等SIMD指令集扩展.通过调用SIMD指令,程序员能够无需理解SIMD技术的硬件层实现细节就方便地使用它的功能.然而,随着熔断、幽灵等处理器硬件漏洞的发现,人们逐渐认识到并行优化技术是一柄双刃剑,它在提高性能的同时也能带来安全风险.本文聚焦于x86 SIMD指令集扩展中的VMASKMOV指令,对它的安全脆弱性进行了分析.本文的主要贡献如下:(1)利用时间戳计数器等技术对VMASKMOV指令进行了微架构逆向工程,首次发现VMASKMOV指令与内存页管理和CPU Fill Buffer等安全风险的相关性;(2)披露了一个新的处理器漏洞EvilMask,它广泛存在于Intel和AMD处理器上,并提出了3个EvilMask攻击原语:VMASKMOVL+Time(MAP)、VMASKMOVS+Time(XD)和VMASKMOVL+MDS,可用于实施去地址空间布局随机化攻击和进程数据窃取攻击;(3)给出了2个EvilMask概念验证示例(Proof-of-Concept,PoC)验证了EvilMask对真实世界的信息安全危害;(4)讨论了针对EvilMask的防御方案,指出最根本的解决方法是在硬件层面上重新实现VMASKMOV指令,并给出了初步的实现方案.

基于QAR数据的波音747-400飞机巡航报文解析研究（英文）

为充分挖掘QAR数据中所包含的大量原始监控数据,检验ACARS报文的可靠性,更好地协助航空公司进行飞机和发动机的状态监控及故障诊断,对发动机稳态报文DFD的报文结构进行了解析研究,提出了一种从QAR数据中提取满足触发条件的DFD报文的研究思路和方法,以丰富发动机性能监控的信息量。通过对B747-400飞机实际ACARS报文数据和所提取的报文数据进行计算分析,验证了该方法的可靠性,具有良好的工程应用前景。

MCS-51系列单片机指令快速记忆法

指令系统是CPU的重要性能指标 ,掌握指令系统是学习单片机及进行单片机开发设计的基础。针对指令繁多及初学者记忆指令难等问题 。