基于FT2232H的高速数据采集系统设计

针对各种虚拟仪器对传输速率和开发难度的要求,设计了一种基于新型USB2．0高速接口的虚拟仪器采集系统。本系统采用FTDI公司第五代USB2．0接口芯片FT2232H,利用其异步FIFO接口与STM32F103的FSMC接口相互传输数据,使用LabView设计上位机界面,调用其提供的动态链接库DLL和MCU固件库,可快速实现高速接口的数据传输。     

主元分析在设备状态监控中的故障检测效率探究

采用大型设备正常运行的传感器数据,通过基于多元统计的主元分析方法建立训练矩阵,利用预测误差进行故障分析工作。不同程度的故障,来分析主元分析方法的检测效率可行性。结果表明,主元分析方法分析故障检测明显,不同传感器的不同故障会对故障诊断存在一定的差异,可行性非常高。     

PIC单片机控制下的无线模块自主选频数据传输

提出一种采用PIC16系列单片机和CC2500无线射频芯片的自主选频无线数据传输系统的设计方法,包括系统硬件电路设计和软件实现。系统具有自主选频功能,解决CC2500在ISM频段内由于同频干扰而产生的频率冲突问题。     

面向知识分享的数字资源版权保护开放模型研究

互联网环境下分享已经成为一种新的趋势,而高校中的知识分享是目前普遍关注的热点问题,随之而来对于数字资源的版权保护面临着更多的挑战。本文以高校为例,从高校的实际情况出发,分析现有的数字资源版权保护模式的实现方式及其存在的问题,并从格式、环节和权限三个方面分别对其进行讨论,提出版权保护模型。     

尾静脉注射方法考察Stearic-PEI/SPIO 纳米基因载体的基因转染性能及磁共振可视化效果研究

实验应用硬脂酸-聚乙烯亚胺包裹超顺磁氧化铁(Superparamagnetic Iron Oxide,SPIO)装载目的基因构建可视化 纳米复合物,进行 BABL/c 雌性小鼠体内磁共振成像实验、组织学检测,探讨其是否能够有效地介导体内基因表达以及 产生磁共振成像(Magnetic Resonance Imaging,MRI)效果。MRI 实验结果显示,对小鼠尾静脉注射复合物 0.5 小时后进 行磁共振扫描,与注射生理盐水的对照组相比实验组 T2 加权信号明显降低,信号强度仅为对照组的 35%;48 小时后, 实验组 T2 加权信号强度略有回升,但与对照组信号强度相比仍存在显著差异。组织学结果显示可视化基因纳米复合物 能够穿过血管内皮细胞进入肝脏组织,并释放 DNA 在细胞内成功表达,但基因表达效果较差。综合 MRI 成像及组织检 查实验结果可知,该纳米颗粒具有优良的 MRI 成像性能,但通过尾静脉注射方法基因转染效率较低。     

A gain and bandwidth enhanced transimpedance preamplifier for Fourier-transform ion cyclotron resonance mass spectrometry

The nature of the ion signal from a 12-T Fourier-transform ion cyclotron resonance mass spectrometer and the electronic noise were studied to further understand the electronic detection limit. At minimal cost, a new transimpedance preamplifier was designed, computer simulated, built, and tested. The preamplifier design pushes the electronic signal-to-noise performance at room temperature to the limit, because of its enhanced tolerance of the capacitance of the detection device, lower intrinsic noise, and larger flat mid-band gain (input current noise spectral density of around 1 pA/√Hz when the transimpedance is about 85 dBΩ). The designed preamplifier has a bandwidth of ~3 kHz to 10 MHz, which corresponds to the mass-to-charge ratio, m/z, of approximately 18 to 61 k at 12 T. The transimpedance and the bandwidth can be easily adjusted by changing the value of passive components. The feedback limitation of the circuit is discussed. With the maximum possible transimpedance of 5.3 MΩ when using an 0402 surface mount resistor, the preamplifier was estimated to be able to detect ~110 charges in a single scan.     

浅谈网络安全技术在政府部门的应用

信息化时代要求信息公开和透明,这就对信息安全的管理提出了更高的要求。信息公开的安全性成为当今社会亟待解决的一大难题,网络安全的建设势在必行。为了更好地监督政府的工作就要进行信息公开,在政府信息公开的过程中一定要保证网络运行的安全。     

Nomadic Speech-Based Text Entry: A Decision Model Strategy for Improved Speech to Text Processing

Speech text entry can be problematic during ideal dictation conditions, but difficulties are magnified when external conditions deteriorate. Motion during speech is an extraordinary condition that might have detrimental effects on automatic speech recognition. This research examined speech text entry while mobile. Speech enrollment profiles were created by participants in both a seated and walking environment. Dictation tasks were also completed in both the seated and walking conditions. Although results from an earlier study suggested that completing the enrollment process under more challenging conditions may lead to improved recognition accuracy under both challenging and less challenging conditions, the current study provided contradictory results. A detailed review of error rates confirmed that some participants minimized errors by enrolling under more challenging conditions while others benefited by enrolling under less challenging conditions. Still others minimized errors when different enrollment models were used under the opposing condition. Leveraging these insights, we developed a decision model to minimize recognition error rates regardless of the conditions experienced while completing dictation tasks. When applying the model to existing data, error rates were reduced significantly but additional research is necessary to effectively validate the proposed solution.     

Exploring the Individual's Behavior on Self-Disclosure Online

Even though the ubiquity of technology can make many aspects of life more convenient, it may simultaneously raise some concerns about the privacy issues related to personal information. This research focused on the individual's behavior toward self-disclosure online and his or her cognition on personal privacy that was affected by not only the personal psychological factors but also the individual's computer knowledge and associated skills. To study how technological and psychological factors can simultaneously affect one's privacy concern and restrain behavior on disclosure, this study applied both perceived privacy and privacy concern to assess such factors as personal subjective attitude, computer self-efficacy, and perceived behavioral control to investigate the technological influence. A hypothesized model was proposed to describe the relationships among these constructs. After structural equation modeling is utilized to analyze the proposed hypotheses, the research findings showed that, although the perceived behavioral control had a negative effect on self-disclosure online, all the other hypotheses indicated a positive casual effect.     

A study of optimal viewing distance in a parallax barrier 3D display

The optimal viewing distance was proposed as a parameter for designing a parallax barrier 3D display. It can be designed based on simple geometric method and by considering the pitches of image display pixels and parallax barrier, or even including the aperture ratios of the image display pixels and parallax barrier. It can be analyzed by using ray tracing method. By considering the optical refraction index of the cover glass, the angular behavior of the system becomes more realistic; however, the geometric method is difficult to be used. We propose a revised method for estimating the view distance and angular behavior. In this paper, we have demonstrated a designated eye position (DEP) for each view and shown that multiple DEPs make a circular curve around the center of the display. We prove the new concept by comparing the optical ray tracing calculations and optical measurement.