A class-B output buffer for flat-panel-display column driver

Due to the large number of output buffers on a column driver chip of a flat-panel display, the quiescent current and die area of the output buffer must be minimized. This paper presents a low static power, large output swing, and wide operating voltage range class-B output buffer amplifier for driving the large column line capacitance in a flat-panel display. A comparator is used in the negative feedback path to eliminate quiescent current in the output stage. The proposed output buffer circuit was implemented in a 0.8 μm CMOS process. Its output voltage swing is from 1 V to the supply voltage. With 5 V supply and 600 pF load, the maximum tracking error is ±7 mV. The measured static current is 24 μA. The settling time for 4 V swing to within 0.2% is 8 μs, which is more than adequate for driving 1280×1024 pixels liquid crystal displays with 86 Hz frame rate and 256 gray levels in each color     

Logical and diversity combining in FH/SSMA packet radio networks

We propose the logical and diversity combining in slotted frequency-hopped spread spectrum multiple access (FH/SSMA) packet radio networks. The proposed diversity scheme employs the symbol-by-symbol logical AND operation between the currently received packet and the previously combined packet. Our results show that the proposed low-complexity diversity combining scheme provides a significant performance improvement over existing diversity combining schemes     

Size-reduction and band-broadening design technique of uniplanarhybrid ring coupler using phase inverter for M(H)MIC's

The hybrid coupler is one of the most fundamental building blocks in microwave and millimeter-wave systems. Ring topology can be often found in the hybrid microwave integrated-circuit design of narrow and broad-band integrated couplers and mixers. In this paper, we propose a new design theory using a phase inverter for systematic size reduction and band broadening of a uniplanar hybrid ring coupler. The features and design criteria of broad-band reverse-phase hybrid ring couplers are presented. Effective bandwidth of a new reverse-phase hybrid ring coupler can be increased by 28% with a return loss of 20 dB. In addition, we present a class of uniplanar phase inverters and discuss their technical aspects. Experimental results show that the bandwidth of the proposed phase inverter is greater than 1.9 octaves with insertion loss below 1 dB and phase shift error of less than ±20°. Measurements confirm that the new uniplanar hybrid ring coupler provides attractive features. Its isolation is better than 20 dB over a 1.8-octave bandwidth attributed to the phase inverter providing almost a frequency-independent phase shift     

Treating late-time instability of hybridfinite-element/finite-difference time-domain method

The hybrid finite element/finite-difference time-domain (FETD/FDTD) method previously proposed to handle arbitrarily shaped dielectric objects is employed to investigate electromagnetic problems of high Q systems for which the transient response over a very long duration is necessary. To begin with, the paper demonstrates that this hybrid method may suffer from late-time instability and spurious DC modes. Then an approach which combines the temporal filtering and frequency shifting techniques is presented to overcome sequentially and, respectively, the two drawbacks. Its accuracy is validated by the favorable comparison with several different methods for the analysis of resonant frequencies and and factors of the various modes in an isolated dielectric resonator. Finally, the present method is applied to calculate the scattering parameters on the microstrip line due to the presence of the cylindrical dielectric resonator     

Entropy-like distance driven fuzzy clustering with local information constraints for image segmentation

To improve the anti-noise ability of fuzzy local information C-means clustering, a robust entropy-like distance driven fuzzy clustering with local information is proposed. This paper firstly uses Jensen-Shannon divergence to induce a symmetric entropy-like divergence. Then the root of entropy-like divergence is proved to be a distance measure, and it is applied to existing fuzzy C-means (FCM) clustering to obtain a new entropy-like divergence driven fuzzy clustering, meanwhile its convergence is strictly proved by Zangwill theorem. In the end, a robust fuzzy clustering by combing local information with entropy-like distance is constructed to segment image with noise. Experimental results show that the proposed algorithm has better segmentation accuracy and robustness against noise than existing state-of-the-art fuzzy clustering-related segmentation algorithm in the presence of noise.     

基于TMS320F2812的永磁同步电机双闭环矢量调速系统

根据永磁同步电机的数学模型和坐标变换的原理,介绍了矢量调速系统,利用数学方程推导了电流环和速度环PI控制器的传递函数和参数解析计算式。基于TMS320F2812平台,结合实际系统,考虑误差和参数补偿,完成双闭环调速系统的设计。实验结果表明,该永磁同步电机双闭环矢量调速系统能够稳定运行,并有良好的控制性能,快速、准确完成闭环调速功能。     

卫星导航欺骗信号检测技术探究

在卫星导航系统已全面应用于国防、社会民生等各方面的今天,保证系统的应用安全已变得越来越重要.通过研究卫星导航欺骗信号的产生原理和类型,对当前各种检测技术的针对性原理和优劣进行了分析比较,从而得出了不同的检测技术应根据应用场景不同、欺骗信号的类型不同、应用领域的不同而有所选择.     

Spatiotemporal Magnetocaloric Microenvironment for Guiding the Fate of Biodegradable Polymer Implants

The degradation behavior of implants is significantly important for bone repair. However, it is still unprocurable to spatiotemporally regulate the degradation of the implants to match bone ingrowth. In this paper, a magneto-controlled biodegradation model is established to explore the degradation behavior of magnetic scaffolds in a magnetothermal microenvironment generated by an alternating magnetic field (AMF). The results demonstrate that the scaffolds can be heated by magnetic nanoparticles (NPs) under AMF, which dramatically accelerated scaffold degradation. Especially, magnetic NPs modified by oleic acid with a better interface compatibility exhibit a greater heating efficiency to further facilitate the degradation. Furthermore, the molecular dynamics simulations reveal that the enhanced motion correlation between magnetic NPs and polymer matrix can accelerate the energy transfer. As a proof-of-concept, the feasibility of magneto-controlled degradation for implants is demonstrated, and an optimizing strategy for better heating efficiency of nanomaterials is provided, which may have great instructive significance for clinical medicine.     

基于异构磁盘阵列的数据备份/恢复技术研究

随着网络技术的快速发展与网络资源的日益丰富。数据的存储量级急速增长,数据保护的重要性显得尤为重要,如何快速有效地对数据进行备份/恢复成为数据保护领域亟待解决的关键问题之一。通过对异构磁盘阵列的数据分配方法进行优化,使不同磁盘阵列间进行数据备份/恢复速率提升。提出划分异构磁盘I/O带宽方式提高磁盘数据读取速度的可行性方案,与传统的数据备份/恢复相比,在时间利用率和备份性能上都得到了很大的提高。     

Budget-constraint mechanism for incremental multi-labeling crowdsensing

Machine learning techniques require an enormous amount of high-quality data labeling for more naturally simulating human comprehension. Recently, mobile crowdsensing, as a new paradigm, makes it possible that a large number of instances can be often quickly labeled at low cost. Existing works only focus on the single labeling for supervised learning problems of traditional machine learning, where one instance associates with only label. However, in many real world applications, an instance may have more than one label. To the end, in this paper, we explore an incremental multi-labeling issue by incentivizing crowd users to label instances under the budget constraint, where each instance is composed of multiple labels. Considering both uncertainty and diversity of the number of each instance’s labels, this paper proposes two mechanisms for incremental multi-labeling crowdsensing by introducing both uncertainty and diversity. Through extensive simulations, we validate their theoretical properties and evaluate the performance.