Link Capacity Sharing between Guaranteed- and Best Effort Services on an ATM Transmission Link under GoS Constraints

While link allocation policies in multi-rate circuit switched loss models have drawn much attention in recent years, it is still an open question how to share the link capacity between service classes in a fair manner. In particular, when an ATM link is offered calls from service classes with/without strict QoS guarantees one is interested in link capacity sharing policies that maximize throughput and keep the per-class blocking probabilities under some GoS constraints. In this paper we propose a model and associated computational technique for an ATM transmission link to which CBR/VBR and ABR classes offer calls. We also propose a simple link allocation rule which takes into account blocking probability constraints for the CBR/VBR calls and a throughput constraint for the ABR calls and attempts to minimize the blocking probability of ABR calls. Numerical examples demonstrate the effectiveness of the policy and of the applied computational technique.     

Combinative Algorithms for the Multidisciplinary Collaborative Simulation of Complex Mechatronic Products Based on Major Step and Convergent Integration Step

Multidisciplinary collaborative simulation (MCS) is an important area of research in the domain of multidisciplinary design optimization (MDO).Although previous research for MCS has to some extent addressed some issues like using of multiple tools,integration stability,control of step size,data synchronization,etc,further work is still necessary to study how to achieve improved precision.A theoretical model is formulated to describe and analyze the integration process of MCS.A basic algorithm with equal maj...     

多业务CDMA系统中基于最大化流量的功率速率联合控制

功率控制技术是CDMA系统中减小多址干扰的一项关键技术。针对TDD-CDMA系统的多速率业务,提出了一种功率速率联合控制算法,速率控制保证不同业务的服务质量要求,通过线性优化过程获得最大化流量时的功率速率分配。仿真结果表明这一算法是一种近似的最优化功率速率联合控制方案,能够有效地提高系统的总容量,优化系统性能。     

多速率STFT超宽带信号瞬时频率估计研究

提出多速率短时傅里叶变换(Multi Rate Short Time Fourier Transform,MR-STFT)瞬时频率估计算法,提高了超宽带信号瞬时频率估计精度;该方法将多速率信号处理算法与短时傅里叶变换(STFT)技术相结合,兼顾采样频率和被测频率,将宽频范围进行分段采样,对分段处理结果进行拟合,构成多速率STFT算法,实现超宽带信号瞬时频率的高精度测量;通过对仿真信号和实测信号进行处理,研究了方法的可行性和频率估计精度,结果表明MR-STFT算法较大提高了超宽带信号瞬时频率估计精度,尤其对低信噪比的超宽带信号效果显著。     

多采样率信号处理在数字化变电站差动保护中的应用

数字化变电站中，差动保护各分支电子式电流互感器（ECT）的采样频率不完全相同时，需要将原各分支ECT的输出数据转换为同一采样频率。文中研究了多采样率信号处理算法和采样数据频率转换对差动保护差电流的影响，通过将信号的抽取和插值环节级联，可以实现任意分数倍采样频率转换。采用基于切比雪夫逼近原理的等波纹设计方法进行低通滤波器设计，与多采样率信号处理算法配合使用，减小了频率混叠造成的误差，从而在ECT应用环境下，将任意不同采样频率的分支电流统一到相同的采样基准下，实现了测量环节与智能电子设备的无缝连接。仿真试验验证了所提出方法的可行性和有效性。     

3G系统中AMR语音业务的链路配置和模式切换的研究

本文针对3G系统中自适应多比特率(AMR)语音业务的各种语音编码模式,设计了采用Turbo码的不等保护信道编码为基础的链路配置方案.为了研究AMR的链路适配,提出了针对3G系统多业务、多接入速率特征的不等功率分配策略,并在此基础上分析了AMR的不同编码模式对小区的接入容量的影响.基于链路级的仿真和对系统容量的分析,本文归纳了3G系统中AMR语音业务的链路配置和模式切换准则,对实际系统中的无线资源管理具有参考价值.     

Ad Hoc网络基于TCP吞吐量的速率自适应技术

目前的IEEE 802.11标准在物理层支持多速率传输,但在媒体接入控制(MAC,Media AccessControl)层却没有相应的速率自适应方法。针对目前Ad Hoc网络自适应速率控制方法的不足和在无线通信环境下TCP性能会大幅度恶化,提出了一种改进的MAC层速率自适应协议,该协议实现简单,与传统标准兼容性好,在提高TCP吞吐量的基础上能适应快速变化的无线信道,且能实现分段数据包的速率自适应传输。仿真结果表明,该协议比RBAR协议有更好的吞吐量。     

Force Feedback Coupling with Dynamics for Physical Simulation of Product Assembly and Operation Performance

Most existing force feedback methods are still difficult to meet the requirements of real-time force calculation in virtual assembly and operation with complex objects. In addition, there is often an assumption that the controlled objects are completely free and the target object is only completely fixed or free, thus, the dynamics of the kinematic chain where the controlled objects are located are neglected during the physical simulation of the product manipulation with force feedback interaction. This paper proposes a physical simulation method of product assembly and operation manipulation based on statistically learned contact force prediction model and the coupling of force feedback and dynamics. In the proposed method, based on hidden Markov model(HMM) and local weighting learning(LWL), contact force prediction model is constructed, which can estimate the contact force in real time during interaction. Based on computational load balance model, the computing resources are dynamically assigned and the dynamics integral step is optimized. In addition, smoothing process is performed to the force feedback on the synchronization points. Consequently, we can solve the coupling and synchronization problems of high-frequency feedback force servo, low-frequency dynamics solver servo and scene rendering servo, and realize highly stable and accurate force feedback in the physical simulation of product assembly and operation manipulation. This research proposes a physical simulation method of product assembly and operation manipulation.     

宽带自适应多速率声码器

介绍了3GPP组织最新推出的宽带自适应多速率声码器AMR－WB，编解码原理以及速率控制机制等。较窄带语音编解码器，在语音的自然度效果及抗噪声能力等方面有较大改善。     

严格线性散播网络编码

针对线性广播和线性散播网络编码在保证节点或节点集解码空间维数方面的不足,提出了一类新的线性网络编码——严格线性散播网络编码.给出了严格线性散播的定义,并设计了相应的构造算法,此种网络编码增强了对网络中任意非源节点集的输入链路上的全局编码核的限制,但其构造所需的有限域的阶并不大于普通的线性散播.此外,还提出了多种转换矩阵的概念,并证明了普通线性散播到严格线性散播的转换矩阵的存在性.结合特殊的数据打包策略,论证了严格线性散播在异构网络中的应用优势:一方面,它能够利用单一网络编码会话实现异构网络中的多速率信息传输;另一方面,它能够为异构网络拓扑结构的扩展提供便利.