Content-adaptive parameters estimation for multi-dimensional rate control

Multi-dimensional rate control schemes have been recently utilized to adapt video streams to dynamic network conditions and heterogeneous devices. However, current multi-dimensional rate control methods, which estimate the model coefficients using fixed update duration, usually yield inaccurate parameters for dynamically changing video content. To address this problem, a content-adaptive parameters estimation scheme is proposed for multi-dimensional rate control. Firstly, we propose to estimate the parameters using dynamical update duration based on video content and the update duration of the model coefficients is determined by jointly considering the varying picture complexity and feedback information from the actual encoding results, which can improve the model parameter estimation accuracy. Secondly, a coarse-to-fine initial parameter calculation method is proposed to refine the initial frame rate according to the channel condition and the video sequence characteristics. Extensive experimental results show that the proposed solutions outperform the state-of-the-art schemes, especially for video sequences with high temporal and spatial complexity. Furthermore, our algorithm also slightly reduces the computational complexity as compared to related algorithms.     

Transparent amorphous zinc oxide thin films for NLO applications

This review focuses on the growth and optical properties of amorphous zinc oxide (ZnO) thin films. A high quality ZnO films fabricated by dip-coating (sol–gel) method were grown on quartz and glass substrates at temperature equal to 350 K. The amorphous nature of the films was verified by X-ray diffraction. Atomic Force Microscopy was used to evaluate the surface morphology of the films. The optical characteristics of amorphous thin films have been investigated in the spectral range 190–1100 nm. Measurement of the polarized optical properties was shows a high transmissivity (80–99%) and low absorptivity (<5%) in the visible and near infrared regions at different angles of incidence. Linear optical properties were investigated by classic and Time-Resolved Photoluminescence (TRPL) measurements. Photoluminescence spectrum exhibits a strong ultraviolet emission while the visible emission is very weak. An innovative TRPL technique has enabled the measurement of the photoluminescence decay time as a function of temperature. TRPL measurements reveal a multiexponential decay behavior typical for amorphous thin films. Second and third harmonic generation measurements were performed by means of the rotational Maker fringe technique using Nd:YAG laser at 1064 nm in picosecond regime for investigations of the nonlinear optical properties. The obtained values of second and third order nonlinear susceptibilities were found to be high enough for the potential applications in the optical switching devices based on refractive index changes. Presented spectra confirm high structural and optical quality of the investigated zinc oxide thin films.     

Application of high-level fuzzy Petri nets to educational grading system

For the purpose of understanding the students’ learning achievement, the most direct way is to implement a test. Due to the rapid development of information technology, all kinds of combination of information technology with the adaptive test have been incessantly noted by many scholars. In general, the computerized adaptive test includes the item response theory that tests the students’ learning ability of subjects. However, the results based only on the dichotomy of correct answers and wrong answers are not so comprehensive judgments. Situations of correct answers and wrong answers should be different in their degrees; for example, completely correct, partially correct, completely wrong, and partially wrong. But the partially correct or partially wrong is vague and difficult to define. Thus it is appropriate to use fuzzy theory to solve the vagueness problem. Therefore, this study presents a novel learning evaluation model which applies high-level fuzzy Petri net (HLFPN) and infers via a fuzzy reasoning method the different answering performances generated by different examinee’s abilities corresponding to the test items in different degrees of difficulty. Finally, we synthesize the answering performance of every test item and make a reasonable evaluation.     

A new cadmium-organic framework fluorescent sensor for Al3 + and Ca2 + ions in aqueous medium

A new metal-organic framework (MOF), [Cd₂(bptc)(HCOO)]·NH₂(CH₃)₂·3H₂O (1), where H₄bptc = 3,3′,5,5′-biphenyltetracarboxylic acid, was obtained by solvothermal reaction. The topology of MOF 1 is a (5,8)-connected net with {4¹⁶ · 5⁸ · 6⁴}{4⁴ · 5⁶}₂ point symbol. MOF 1 shows high stability in aqueous solution. Luminescence study indicates that MOF 1 possesses selective turn-on luminescent sensing functions towards Al^3 + and Ca^2 + ions in aqueous solutions.     

Palm-print recognition by matrix discriminator

In this study, the characteristic matrix is employed to generate the various discriminators, by which to identify different palm-prints. The “ring rotation invariant transform” technique can deal with image rotation problem. In this study, the transformed signals will be fed to the characteristic matrix to generate various discriminators. For dealing with image-shifting problem, one pixel in sample image is compared with the surrounding pixels in unknown image to locate the closest matching. The comparison approaching in this study is by the basis of pixel-to-pixel-comparisons.     

AlGaN/GaN HEMT场板结构对与表面态相关的延迟特性的影响

为了研究AlGaN/GaN HEMT器件中场板结构对电流崩塌效应影响的物理机理,我们运用数值模拟的方法研究了场板结构和与表面态相关的栅延迟现象之间的关系。模拟显示场板结构可以显著地抑制电流崩塌效应的强度,但是对延迟时间没有影响。场板结构可以增大AlGaN表面附近的空穴积累,导致表面态的离化率增大从而抑制器件的电流崩塌。     

基于电桥的高精度电阻测量系统的设计与实现

针对现有的电阻测量仪器和设备对于电阻测量的精度不高以及价格昂贵的问题,设计了一款基于电桥的高精度电阻测量系统。系统采用电桥电路作为测量电路,利用STM32F103RBT6单片机作为控制核心,主要通过基准电压电路和A／D模块电路实现测量电阻数据的采集与模数转换,同时,为了实现对电阻的高精度测量,通过硬件去耦滤波和软件数字滤波及误差补偿2种方式共同减小了接触电阻、导线电阻以及其他各类噪声的影响。系统在测量电阻时可以通过液晶显示六位有效位数字,即精度可达到十万分之一,分辨率为1mΩ;它具备电阻测量的操作简单、数据采集稳定、灵敏度高和成本低廉等特点,可以对各类电阻包括精密电阻的阻值测量,并且适用于应用于实验、维修和工程开发等多种场合。     

基于点识别的自动报靶系统

设计分为激光枪打靶和激光枪着落点识别两个部分。在正式打靶前,需要手动按键进行靶心和靶环间的距离校准,校准完成后可正式打靶。正式打靶时,手动按键控制激光枪上下左右移动并发射激光束,通过按键控制摄像头采集激光点的信息。采集完成后,通过按键控制在液晶显示屏上显示相应的闪烁点,同时在显示屏上显示激光点的方位信息和环数信息。