Smooth Control of Adaptive Media Playout for Video Streaming

Client-side data buffering is a common technique to deal with media playout interruptions of streaming video caused by network jitters and packet losses of best-effort networks. However, stronger playout interruption protection inevitably amounts to larger data buffering and results in more memory requirements and longer playout delay. Adaptive media playout (AMP), also a client-side technique, can reduce the buffer requirement and avoid buffer outage but at the expense of visual quality degradation because of the fluctuation of playout speed. In this paper, we propose a novel AMP scheme to keep the video playout as smooth as possible while adapting to the channel condition. The triggering of the playout control is based on buffer variation rather than buffer fullness. Experimental results show that our AMP scheme surpasses conventional schemes in unfriendly network conditions. Unlike previous schemes that are tuned for a specific range of packet loss and network instability, the proposed AMP scheme maintains consistent performance across a wide range of network conditions.     

Design of self-bias tail transistor technique for low phase noise CMOS VCO with harmonic suppression using capacitance ground

This paper presents a low phase noise wideband CMOS VCO based on the self-bias tail transistor technique and harmonic suppression using a capacitance ground. This VCO utilizes switching capacitor arrays in which four channels are able to be selected for multi-band application. Moreover, the design of CMOS VCO makes good use of the self-bias tail transistor and capacitance ground filter technique to reduce the phase noise. The MOS varactors are used as fine tuning for wideband operating application. The fully integrated VCO provides excellent performance with high FOM −193 dBc/Hz. The bandwidth of the frequency is 1.1 GHz and the tuning range is 13.8%. The power dissipation of the core circuit is 8.28 mW under a 1.8 V supply and phase noise is measured as low as −123.6 dBc/Hz at 1 MHz offset under 8.5 GHz oscillation frequencies. This VCO was made by the TSMC 0.18 μm 1P6M CMOS standard process and the chip area is 0.75×0.69 (mm²).     

休闲食品加工技术研究进展

休闲食品伴随人们生活方式和食品科技及产业的发展得到迅速发展,已成为人们日常生活中不可缺失的部分。休闲食品行业的快速发展除了归功于政策推动,极为重要的发展动力还源于支撑整个行业前进的食品加工技术,其中包括膨化技术、挤压技术、油炸技术、脱水干燥技术等。这些关键的加工技术在近年来也发生了极大的变化,呈现出复合化的趋势,这些改变克服了很多以往加工中的缺点,拓宽了原料选择范围,丰富了产品种类,优化了产品质量。本文综述了休闲食品中重要的膨化技术、挤压技术、油炸技术、脱水干燥技术的应用及其研究进展,意在推动休闲食品创新发展的步伐。     

液相色谱/元素分析仪-同位素质谱法鉴定蜂蜜 掺假的方法改进

目的改进液相色谱/元素分析仪-同位素质谱法鉴别蜂蜜掺假的方法。方法对现有欧盟标准方法优化液相色谱条件,结合元素分析仪-同位素质谱法,将二糖分离为麦芽糖、蔗糖,提出一个新的参数—麦芽糖、蔗糖δ~(13)C值之差δ~(13)C_(M-S)。结果根据本研究检测113个国内外不同来源纯正蜂蜜样本的数据,提出纯正蜂蜜δ~(13)C值新要求:蜂蜜蛋白质与蜂蜜同位素差值δ~(13)C_(P-H)大于-0.97‰;果糖、葡萄糖δ~(13)C值之差δ~(13)C_(F-G)在-0.60‰至0.56‰范围内;麦芽糖、蔗糖δ~(13)C值之差δ~(13)C_(M-S)在-0.73‰至0.98‰范围内;各个组分δ~(13)C最大差值δ~(13)C_(max)小于2.05‰;根据上述4个参数来确认蜂蜜是否掺假。在日常检测和市场销售的160个样品中,原方法阳性检出率为16.2%,而新方法阳性检出率达21.9%。结论本研究提升了蜂蜜掺假检测能力,此方法的建立更好、更精确打击掺假的同时,也维护消费者权益。     

Design of low power UWB LNA based on common source topology with current-reused technique

This paper presents two low power UWB LNAs with common source topology. The power reduction is achieved by the current-reused technique. The gain and noise enhancement of the proposed circuit is based on an output buffer which is used by a common source amplifier with shunt–shunt feedback. Chip1 is an adopted T-match input network of 50 Ω matching in the required band. Measurements show that the S₁₁ and S₂₂ are less than −10 dB, and the maximum amplifier gain S₂₁ gives 9.7 dB, and the noise figure is 4.2 dB, the IIP3 is −8.5 dBm, and the power consumption is 11 mW from 1.1 V supply voltage. The input matching of chip2 is adopted from a LC high pass filter and source degenerated inductor. The output buffer with the RC-feedback topology can improve the gain, increase the IIP3, restrain the noise, improve the noise figure and decrease the DC power dissipation. Measurements show 13.2 dB of power gain, 3.33 dB of noise figure, and the IIP3 is −3.3 dBm. It consumes 9.3 mW from 1.5 V supply voltage. These two chips are implemented in a 0.18 μm TSMC CMOS process.     

A transient three-dimensional inverse geometry problem in estimating the space and time-dependent irregular boundary shapes

A transient three-dimensional shape identification problem (inverse geometry problem) to determine the unknown irregular and moving boundary configurations by utilizing the steepest descend method (SDM) and a general purpose commercial code CFD-RC is successfully developed and examined in this study based on the simulated measured temperature distributions on the bottom surface by infrared thermography. The advantage of calling CFD-RC as a subroutine in the present inverse calculation lies in that its auto-mesh function enables the handling of this moving boundary problem. Results obtained by using the technique of SDM to solve the inverse geometry problem are justified based on the numerical experiments. Two test cases are performed to test the validity of the present algorithm by using different types of boundary shapes, initial guesses and measurement errors. Results show that reliable estimations on the unknown space and time-dependent boundary geometry can be obtained when the measurement errors are considered.     

Stability of 4-DMAP in Solution

A stability-indicating reversed-phase performance liquid chromatographic method was developed for the detection of 4-(N, N-dimethylamino)phenol (4-DMAP) and its degradation products under accelerated degradation conditions. The degradation kinetics of 4-DMAP in aqueous solution over a pH range of 1.12-6.05 and its stability in solutions based on propylene glycol or polyethylene glycol 400 were investigated. The observed rate constants were shown to follow apparent first-order kinetics in all cases. The pH rate profile shows that maximum stability of 4-DMAP was observed in the pH range 2.0 to 3.0. Acid/base catalysis of 4-DMAP was not affected by systems of various ionic strengths. Incorporation of nonaqueous propylene glycol or polyethylene glycol 400 in the pH 3.05 solution of 4-DMAP showed an increase in the stability at 55°C ± 0.5°C.     

行程时间预测方法研究

行程时间预测,有助于实施高级旅行者信息系统.自20世纪90年代起,已经有多种行程时间预测方法被研发出来.将行程时间预测方法分为模型驱动方法和数据驱动方法两大类.介绍了两种常见的模型驱动方法,即排队论模型和细胞传输模型.数据驱动方法被分类为参数方法和非参数方法：参数方法包括线性回归、自回归集成移动平均和卡尔曼滤波,非参数方法包括神经网络、支持向量回归、最近邻和集成学习方法.对现有行程时间预测方法从源数据、预测范围、准确率、优缺点和适用范围等方面进行了分析总结.针对现有方法的一些缺点,提出了可能的解决方案.给出了一种新颖的数据预处理框架和一个行程时间预测模型,最后指出了未来的研究方向.     

有关时间自动机重置的若干问题的计算复杂性

自动机的重置序列也称为同步序列,具有以下特性：有限自动机通过运行重置序列w,可从任意一个未知的或无法观测到的状态q₀到达某个特定状态q_w.这仅依赖于w,而与开始运行w时的状态q₀无关.这一特性可用于部分可观察的复杂系统的自动恢复,而无需重启,甚至有时不能重启.基于此,重置问题自出现以来便得到关注和持续研究.最近几年,它被扩展到可以描述诸如分布式、嵌入式实时系统等复杂系统的无限状态模型上,比如时间自动机和寄存器自动机等.以时间自动机的重置问题的计算复杂性为研究对象,发现重置问题与可达性问题有着紧密的联系.主要贡献是：（1）利用时间自动机可达性问题的最新成果,完善完全的确定的时间自动机重置问题的计算复杂性结论;（2）对部分规约的确定的时间自动机,研究得出,即使在输入字母表大小减至2的情况下,其复杂性仍是PSPACE-完全的;特别地,在单时钟情况下是NLOGSPACE-完全的;（3）对完全的非确定的时间自动机,研究得出其D_i-可重置问题（i=1,2,3）是不可判定的,其重置问题与非确定的寄存器自动机重置问题在指数时间可以相互归约,通过证明指数时间归约相对高复杂性类具有封闭性,利用非确定的寄存器自动机的结论得出单时钟的时间自动机的重置问题是Ackermann-完全的、限界的重置问题是NEXPTIME-完全的.这些复杂性结论,说明关于时间自动机的重置问题大都是难解的,一方面,为时间系统的可重置性的检测和求解奠定坚实的理论基础,另一方面,为以后寻找具有高效算法的特殊结构的时间系统（即具有高效算法的问题子类）给予理论指导.     

Rapid formation of methane hydrates with compact agglomeration via regulating the hydrophilic groups of nanopromoters

Gas hydrates have been endowed with great potential as the medium for natural gas storage & transportation. In this work, we prepared novel nanopromoters by grafting hydrophilic groups ( SO₃⁻,  COO⁻ and  N[CH₃]₃⁺) covalently on polystyrene nanospheres (Group@PSNS), and for the first time achieved rapid formation of methane hydrates together compact agglomeration by regulating the hydrophilic groups on the surface of nanopromoters. When  SO₃⁻@PSNS was used, methane hydrates formed rapidly but loosely in the reactor; while for  COO⁻@PSNS and  N(CH₃)₃⁺@PSNS, even the hydrate formation rate was seriously reduced, the formed hydrates agglomerated compactly in the reactor bottom. Interestingly, when both  SO₃⁻ and  COO⁻ were fixed on the nanospheres, both the hydrate growth rate and agglomeration compactness were controlled. Especially, the nanopromoter with the  SO₃⁻/ COO⁻ molar ratio of 2:1 resulted in the formation of methane hydrates with compact agglomeration morphology within 1–2 hr and with the storage capacity reaching 140–145 vol/vol.