脸由音生：语音驱动的静动态人脸生成方法

语音驱动人脸生成旨在挖掘语音片段和人脸之间的静动态关联性,进而由给定的语音片段生成对应的人脸图像。然而已有的研究方法大多只考虑其中的一种关联性,且对静态人脸生成的研究严格依赖于时序对齐的音视频数据,在一定程度上限制了静态模型的使用范围。提出了一种基于条件生成对抗网络的语音驱动静动态人脸生成模型（SDVF-GAN）。该模型基于自注意力机制构建语音编码器网络以获得更为准确的听觉特征表达,并将其作为静态生成网络和动态生成网络的输入;静态生成网络利用基于投影层的图像判别器合成出属性一致（年龄、性别）且高质量的静态人脸图像,动态生成网络利用基于注意力思想的嘴唇判别器和图像判别器合成出嘴唇同步的动态人脸序列。实验利用所构建的属性对齐的Voice-Face数据集和公共的LRW数据集分别训练静态人脸生成网络和动态人脸生成网络。结果表明,该模型综合研究了语音和人脸之间的属性对应和嘴唇同步关系,实现了质量更高且关联性和同步性更强的人脸图像生成。     

一种新的CDMA系统自适应变步长功率控制算法

下一代无线网络主要是支持非连续的数据包通信。在这种情况下,功率控制显得尤为重要。相对于语音通信来说数据对时延不太敏感,因此可以根据信道条件的好坏来决定是否发送数据,即条件好的时候发不好的时候暂停发送。基于这点本文提出了一种针对CDMA系统的多径环境下的基于信干比估算的自适应变步长功率控制算法,系统采用这种算法来对发送功率进行控制将会取得更好的性能。     

一种新的CDMA系统自适应变步长功率控制算法

下一代无线网络主要是支持非连续的数据包通信.在这种情况下,功率控制显得尤为重要.相对于语音通信来说数据对时延不太敏感,因此可以根据信道条件的好坏来决定是否发送数据,即条件好的时候发不好的时候暂停发送.基于这点本文提出了一种针对CDMA系统的多径环境下的基于信干比估算的自适应变步长功率控制算法,系统采用这种算法来对发送功率进行控制将会取得更好的性能.     

面向设计过程的项目管理系统安全访问模型

信息访问控制是信息共享系统不可缺少的功能。在项目管理系统中，协同的工作环境需要一种新的访问控制模式。文中提出了一种新的静态访问控制模型和动态访问模型相结合的安全模型，并给出了一种有效的缺省授权机制，大大简化了的系统的授权和访问控制。     

基于信任的动态多级访问控制模型

针对传统基于角色的访问控制(Role-Based Access Control, RBAC)系统中的访问资源共享伸缩性有限、安全性不足及权限需预先设定分配等问题，为了提高权限控制的兼容性，细化访问控制粒度，本文提出一种基于信任的动态多级访问控制模型(Trust-Based Dynamic Multi-level Access Control Model, TBDMACM)，通过用户的静态角色及动态信任度获得相应的权限授权，保证数据机密性和访问过程安全可控。实验结果表明，这种访问控制方式能够有效地防止恶意访问，较好地解决系统权限伸缩性问题。     

基于客户端对XML文档的访问控制管理

对XML文档的访问控制管理的研究目前是个热点问题,已有诸多文献提出了许多访问控制模型,它们大多是以静态的方式共享加密数据。然而在某些情况下,会出现临时的、动态的访问控制规则,这样静态模型就不能解决这种情况。随着客户端设备软硬件的发展,出现了基于客户端的动态访问控制方案。本文提出了一个结合静态模型和动态模型的新的混合方案,举例介绍了基于客户端的动态访问控制部分,并与纯动态方案在性能上作了比较。     

智能电网中基于MQTT协议的ABAC访问控制方案

在智能电网环境中,电力运营商和消费者通过智能电表进行大量高精度的用电数据的实时监测,用户机密数据持续暴露于未经授权的访问,在这种传统通信模式下,智能电表对家庭用户能源消耗的细粒度测量造成了严重的隐私安全问题,而现有的静态访问控制方法并不满足智能电网环境基于上下文的动态访问特性。针对此问题,提出一种基于物联网通信协议（MQTT协议）的访问控制方案,通过在MQTT协议中对树型结构的主题列表设计基于ABAC访问控制模型的动态上下文授权策略,并在WSO2系统使用XACML策略语言实现了提出的访问控制方案。性能评估结果表明,该方案能在较低的通信开销内支持动态的访问控制,以解决智能电网中用户的用电信息未经授权而泄露的隐私安全问题。     

铅酸蓄电池组容量测试与活化技术研究与实现

针对当前国内外铅酸蓄电池容量测试及活化设备智能化程度低、容量快速预测误差大和功能简单等问题,提出一种基于遗传退火优化BP神经网络的蓄电池剩余容量快速预测算法和劣化蓄电池活化诊治方法。研制了基于ARM9和μC／OS-Ⅱ嵌入式操作系统平台的蓄电池容量预测与活化诊治系统。系统由总控、充电和放电三个单元组成,各单元通过RS-485总线构成分布式测控系统,具有蓄电池充电、放电、剩余容量快速预测和劣化电池活化等功能。     

自动引导车电池SOC估算方法研究

自动引导车(AGV车)工况特殊,电流积分法估算电池剩余容量(SOC)误差较大,而且存在累积误差;为了提高AGV车电池剩余容量估算的准确度,对扩展卡尔曼滤波法估算AGV车电池剩余容量进行了研究,分析了AGV车特殊工况,提出将扩展卡尔曼滤波法的滤波增益改进为动态调整滤波增益,有效提高扩展卡尔曼滤波法的跟踪效果;实验表明使用扩展卡尔曼滤波法估算AGV车电池剩余容量精度较高,采用动态校正的滤波增益提高了估算过程的跟踪效果,解决了AGV车电池剩余容量估算不准确的问题。     

基于ARM9的CDMADTU无线数据传输系统设计实现

将嵌入式技术和CDMA无线网络技术相结合,设计了基于ARM9处理器的现场数据自动采集和无线传输系统。该系统实现数据采集及A／D转换,数据经串口到CDMA,然后转换为TCP/IP数据包,使用CDMADTU发送数据,连接无端Web服务器,提供实时数据的远程采集和传输。     

Voice and video transmissions with global data parameter control for the IEEE 802.11e enhance distributed channel access

Best-effort data control and admission control are vital to guarantee quality of service for real-time (voice and video) transmissions in the IEEE 802.11e wireless LANs. In this paper, we propose and study a global data parameter control scheme integrated with a measurement-based admission control scheme for the IEEE 802.11e enhanced distributed channel access. In the proposed global data control scheme, the access point dynamically controls best-effort data parameters of stations globally based on traffic condition. Such a global/centralized data parameter control mechanism provides the best fairness for data transmissions among stations. In the proposed centrally-assisted distributed admission control scheme for voice and video transmissions, stations listen to available budgets from the access point to make decisions on acceptance or rejection of a voice or video stream. Such a scheme provides good differentiation among different access categories and provides good fairness among real-time streams within the same access category. The proposed mechanisms are evaluated via extensive simulations. Studies show that, with the proposed global data control scheme and the admission control scheme, quality of service can be greatly improved while maintaining a good utilization.     

A novel CFO estimator with joint bisection-searching and complexity-reduction technique for uplink MC-CDMA systems

This paper presents a simple scheme, which speeds the estimation of carrier frequency offset (CFO) as well as reducing the estimation complexity for multicarrier code-division multiple-access (MC-CDMA) uplink. Based on the concept of bisection method, the CFO is efficiently estimated by way of locating the peak value in the output power spectrum of the minimum output energy (MOE) detector. Complexity reduction results from the proposed data vector partition associated with an innovative data processing technique for the MOE detector. Simulation results show that the expected advantage of the proposed scheme can be achieved at the expense of a reasonable performance loss even in the presence of a large CFO.     

工作流管理系统中的访问控制机制

介绍了传统的访问控制,指出了静态的基于角色的访问控制在工作流管理系统中不能被直接套用,基于工作流的访问控制应采用静态授权和动态控制相结合的方式来解决,并阐述了其基于角色的静态授权和基于任务的动态控制机制。     

Stochastic sampling algorithms for state estimation of jump Markovlinear systems

Jump Markov linear systems are linear systems whose parameters evolve with time according to a finite-state Markov chain. Given a set of observations, our aim is to estimate the states of the finite-state Markov chain and the continuous (in space) states of the linear system. The computational cost in computing conditional mean or maximum a posteriori (MAP) state estimates of the Markov chain or the state of the jump Markov linear system grows exponentially in the number of observations. We present three globally convergent algorithms based on stochastic sampling methods for state estimation of jump Markov linear systems. The cost per iteration is linear in the data length. The first proposed algorithm is a data augmentation (DA) scheme that yields conditional mean state estimates. The second proposed scheme is a stochastic annealing (SA) version of DA that computes the joint MAP sequence estimate of the finite and continuous states. Finally, a Metropolis-Hastings DA scheme based on SA is designed to yield the MAP estimate of the finite-state Markov chain. Convergence results of the three above-mentioned stochastic algorithms are obtained. Computer simulations are carried out to evaluate the performances of the proposed algorithms. The problem of estimating a sparse signal developing from a neutron sensor based on a set of noisy data from a neutron sensor and the problem of narrow-band interference suppression in spread spectrum code-division multiple-access (CDMA) systems are considered     

Adaptive fuzzy power control for WCDMA mobile radio systems

In this paper a fuzzy logic based power control for a direct sequence, wideband code-division multiple-access (DS/WCDMA) cellular phone system is introduced. A power control procedure is needed to compensate the fluctuation of the mobile's transmitting power received in a base station and to increase the capacity of mobile communication systems.The input variables of the controller are the power error and the change of the error. The output is the power step size. Simulation results show that the developed fuzzy proportional-integral control stabilizes the power level and decreases the overshoot and rise time.     

一种基于正弦激励的线性预测模型的语音转换方法

在正弦激励模型的线性预测(LP)残差转换的基础上,提出了一种改进语音特征转换性能的语音转换方法.基于线性预测分析和综合的构架,该方法一方面通过谱包络估计声码器提取源说话人的线性预测编码(LPC)倒谱包络,并使用双线性变换函数实现倒谱包络的转换;另一方面由谐波正弦模型对线性预测残差信号建模和分解,采用基音频率变换将源说话人的残差信号转换为近似目标说话人的残差信号.最后由修正后的残差信号激励时变滤波器得到转换语音,滤波器参数通过转换得到的LPC倒谱包络实时更新.实验结果表明,该方法在主观和客观测试中都具有良好的结果,能有效地转换说话人声音特征,获得高相似度的转换语音.     

A novel congestion control in hybrid ATM/TDMA networks

A new congestion control scheme is analyzed for an ATM multiplexer node. This scheme is based on the leaky bucket and virtual leaky bucket techniques, and utilizes the interaction between the ATM and higher layers, in a hybrid asynchronous transfer mode/time division multiple access (ATM/TDMA) network. The transport users are assumed to be generic ATM sources, who modulate their end-to-end flow control parameters, i.e. protocol data unit size in case of video and voice users, and window size in case of data users, based on the congestion status. Simple analytical formulas are derived for congestion criteria, to represent the required bandwidth to support various classes of service, i.e. video, voice, data, etc. with their own performance requirements. An ATM multiplexer node buffer is analyzed using a modulated poisson process queuing model with bulk arrival and bulk service of cells. The ATM multiplexer node congestion performance criteria, i.e. the mean probabilities of ATM multiplexer node congestion, cell generation, cell discarding, buffer content and buffer overflow, are evaluated with and without the congestion control schemes.     

一种新的基于H.264/AVC的零块判决方法

在基于运动估计和预测编码的视频编码方案中,有一种简单而有效的快速实现方法——零块判决方法,H．264／AVC使用的也是基于运动估计和预测编码的视频编码方案,所以也可以运用零块判决方法来加快其编码速度．根据H．264／AVC视频编码标准的新特点,对其中的零块判决阈值进行了推导,提出了新的适合于H．264／AVC的零块判决方法,并进行了仿真测试,实验结果表明,在中低码率的视频编码中,该方法在编码效率基本保持不变的条件下,编码时间减少了20％～47％．     

A frame-level encoder rate control scheme for transform domain Wyner-Ziv video coding

Available distributed video coding codecs are mostly based on decoder rate control scheme where the parity bits for decoding can be achieved over a feedback channel. Meanwhile, the frequent requests over feedback channel increase the transmission delay. The feedback-free distributed video coding, relying on encoder rate control in literatures, has overcome the aforementioned shortcoming. However, when performing parity bitrate estimation and other operations, the feedback-free distributed video coding systems based on bit-plane usually require high precision of bitrate estimation and high quality of side information at the encoder. In this paper, we propose a frame-level distributed video coding system based on encoder rate control. The innovations include three parts: 1) an adaptive coding mode selection algorithm is proposed, which utilizes both temporal and spatial correlation and reduces the complexity of encoder; 2) a bit-plane rearrangement method is adopted, which makes the coding rate on each bit-plane homogeneous and effectively reduces the accuracy requirement of the parity bitrate prediction and improves the efficiency of rate estimation; 3) a frame-level parity bitrate estimation scheme is presented to enhance the efficiency of rate estimation on the basis of a look-up table. Numerical results verify that the proposed scheme remarkably improves the rate distortion performance of distributed video coding at low bitrate.     

基于相关性分析的多模式多视点视频编码

多视点视频编码方法除需具有较高编码效率外,还必须支持视点或时间的随机访问、低延时编解码、视点可分级等性能.多视点视频信号的时间、视点间相关性随相机密度、光照、对象运动等因素不同而变化.文中提出基于多视点视频信号相关性分析的多模式多视点视频编码方法,改变传统单一预测模式的多视点编码结构,将多种性能优良的预测编码模式有机结合,根据多视点视频相关性分析灵活选择合适的预测编码模式,以获得优异的编码综合性能.实验结果表明,所提出的多模式多视点视频编码方法在保证高压缩效率的前提下,可进一步降低复杂度,提高随机访问性能.