空时分组码在TD—SGDMA系统中的应用

作为MIMO构架核心环节的空时编码技术，是一种新兴而颇具潜力的方案，能够有效提高无线频谱利用率，其中的空时分组码是一种有效的发射分集方案。本文提出了一种适用于多根发射天线的空时分组码与TD—SCDMA系统的结合方案，仿真结果证明它可提高TD—SCDMA系统性能。     

空时分组码在TD-SCDMA系统中的应用

作为MIMO构架核心环节的空时编码技术,是一种新兴而颇具潜力的方案,能够有效提高无线频谱利用率,其中的空时分组码是一种有效的发射分集方案。本文提出了一种适用于多根发射天线的空时分组码与TD-SCDMA系统的结合方案,仿真结果证明它可提高TD-SCDMA系统性能。     

空时分组码技术分析与仿真

空时编码作为无线通信中一种新的编码和信号处理技术,它使用多个发射和接收天线进行信息的发射与接收,可以大大改善无线通信系统的信息容量和信息率.本文着重分析了空时编码中的空时分组码,并借助MATLAB仿真平台对其误码性能进行仿真.结果表明,随着发射天线和接收天线数日的增加,其误码性能明显改善,具有较高的实用价值.     

对角分层酉空时编码策略

高速率、高性能、高容量的多输入多输出（MIMO：Multi-lnput Multi-Output）技术已被公认为是实现未来宽带移动通信的一种有效传输方案。酉空时码具有较高的编码增益和分集增益,能够在很大程度上提高MIMO系统的误码性能。但在高速率下,由于酉空时码采用了高阶调制方式,其误码性能则会急剧下降。针对传统酉空时码的缺点,本文提出了一种对角分层酉空时编码策略。该策略通过在不同的对角分层传送较低阶数的调制信号实现高速率传输,避免了高阶调制方式的采用,进而能够有效提高系统的误码性能。仿真结果表明,提出的对角分层酉空时编码策略能够获得比已有的其他多种编码方案更好的误码性能,适用于对误码性能和传输速率要求很高的B3G（Beyond 3rd Generation）系统。     

对角分层酉空时编码策略

高速率、高性能、高容量的多输入多输出（MIMO：Multi-lnput Multi-Output）技术已被公认为是实现未来宽带移动通信的一种有效传输方案。酉空时码具有较高的编码增益和分集增益,能够在很大程度上提高MIMO系统的误码性能。但在高速率下,由于酉空时码采用了高阶调制方式,其误码性能则会急剧下降。针对传统酉空时码的缺点,本文提出了一种对角分层酉空时编码策略。该策略通过在不同的对角分层传送较低阶数的调制信号实现高速率传输,避免了高阶调制方式的采用,进而能够有效提高系统的误码性能。仿真结果表明,提出的对角分层酉空时编码策略能够获得比已有的其他多种编码方案更好的误码性能,适用于对误码性能和传输速率要求很高的B3G（Beyond 3rd Generation）系统。     

闭环模式的线性空时分组码

介绍了正交空时分组码的模型，自干扰，性能；并由此提出了一种高速率准正交空时分组码的闭环模式，保证MIMO系统获得较高的速率，同时减少由于正交性减弱而引起的性能下降。其中反馈的方法就是根据发射端能够获得部分信道状态信息而提出的，这种自适应模式的性能在瑞利衰落信道下通过仿真得到了验证。     

MIMO—OFDM系统中空时分组编码技术性能仿真研究

将OFDM和MIMO两种技术相结合,能达到两种效果,即系统很高的传输速率和通过分集达到很强的可靠性。文中给出了空时分组码在OFDM系统中的系统模型,并通过MATLAB仿真,比较了MIMO—OFDM系统与OFDM系统,得出系统性能有了明显提高。     

一种高速级联卷积空时分组码的设计方法

空时分组码能够提供分集增益,但是不能提供编码增益,为了提高空时分组码的可靠性能,本文提出一种高速卷积空时分组码的设计方法.该方法将高速空时分组码和删余卷积码进行级联,既保证了传输速率又提供了编码增益.     

GEO卫星通信中空时协同性能分析

GEO卫星通信的用户下行链路为典型的衰落信道,经卫星转发的信号如果经历大尺度衰落,则用户端接收到的信号将产生大范围失真。该文针对GEO卫星通信的特点,为了提高GEO卫星系统的通信性能,考虑将空时协同技术引入到GEO卫星通信中。并仿真分析了在不同信道环境下,使用不同分集方案时GEO卫星通信系统性能,结果显示使用空时协同技术后,系统的可靠性有明显提高。     

分布式空时码在协同通信系统中的研究

空时编码技术是提高频谱利用率和抗信道表落的一种最新编码技术;在发射端和接收端,系统利用多个天线大大改善了无线通信系统的性能.协同通信构建一个虚拟的MIMO系统,利用分布式空时码可以极大地提高移动通信系统的可靠性或有效性.     

基于网络的显示器展示系统的研究与实现

本文根据显示器行业的需求与现状,结合互联网三维技术、虚拟现实以及网络数据库等技术,开发了一个基于网络的显示器展示系统。实践证明,通过本系统,企业可以了解用户的产品需求信息,满足用户的个性化定制需求:用户可以通过简单的键盘和鼠标交互操作,全面了解显示器的各项信息,在虚拟现实环境中动态地感受可视化的产品设计效果。     

An improved event-triggered control method for fuzzy systems under membership functions online learning

This paper is concerned with the problem of adaptive event-triggered (AET) based optimal fuzzy controller design for nonlinear networked control systems (NCSs) characterized by Takagi–Sugeno (T–S) fuzzy models. An improved AET communication scheme with a memory adaptive rule is proposed to enhance the utilization of the state response vertex data. Different from the existing ET based results, the improved AET scheme can save more communication resources and acquire better system performance. The sufficient criteria of performance analysis and controller design are presented for the closed-loop control system subject to mismatched membership functions (MFs) and AET scheme. And then, a new MFs online learning algorithm on the basis of the gradient descent approach is employed to optimize the MFs of fuzzy controller and obtain optimal fuzzy controller for further improving system performance. Finally, two simulation examples are presented to verify the advantage and effectiveness of the provided controller design technique.     

一种新的P2P流媒体直播系统方案

文章通过对P2P流媒体直播系统相关技术的研究和分析,概况并总结了现有技术的优缺点,在此基础上提出了一种新的P2P流媒体直播系统方案。该方案采用基于单树一多树结合的组播树构建方法,并给出了相应的节点管理策略。通过实验,该方案提高了流媒体直播系统的实时性、可用性和服务质量。     

Fuzzy logic controller aided expert relaying mechanism system

Protection and reliability enactment of electrical systems are important and emerging in power system research. Nowadays, it is very evident that the implementation of an intelligent algorithm is found in the field of substation equipment protection and relaying purposes. Majority of the researches are based on single load connected to a single feeder line and validated using simulation. A hardware based implementation and validation system will be an additional aspects. In this paper, we have discussed an expert system based intelligent relaying scheme by incorporating fuzzy algorithm in microcontroller. Purpose is to control the moving contacts of the breaker part for controlling multiple loads connected to a single feeder line. This paper reports the entire performance of intelligent relaying mechanism only considering stage - I with respect to non-fuzzy based relaying scheme and successfully achieved fastest coordination time after validating it under IEEE 13 Bus system. We have also validated the cascaded fuzzy based system and a non-fuzzy based system using ATMEL microcontroller.     

双暗态原子系统动力学行为的量子相干控制研究（英文）

量子相干控制前沿问题及应用研究是本世纪物理学前沿领域的重要研究内容。而基于暗态的量子相干控制技术已经导致了在相干布居捕获、绝热跟随、量子信息等多方面的应用。本论文主要进行双暗态原子系统动力学行为的若干量子相干控制研究，包括：双暗态四能级原子系统的绝热跟随特性研究；双暗态作用提高克尔非线性的新方案提出；自发辐射诱导相干实现非线性极化率的提高以及双通道高效四波混频过程的实现等。     

Output feedback robust H∞ control for spacecraft rendezvous system subject to input saturation: A gain scheduled approach

In this paper, the problem of output feedback robust H_∞ control for spacecraft rendezvous system with parameter uncertainties, disturbances and input saturation is investigated. Firstly, a full-order state observer is designed to reconstruct the full state information, whose gain matrix can be obtained by solving the linear matrix inequality (LMI). Subsequently, by combining the parametric Riccati equation approach and gain scheduled technique, an observer-based robust output feedback gain scheduled control scheme is proposed, which can make full use of the limited control capacity and improve the control performance by scheduling the control gain parameter increasingly. Rigorous stability analyses are shown that the designed discrete gain scheduled controller has faster convergence performance and better robustness than static gain controller. Finally, the performance and advantage of the proposed gain scheduled control scheme are demonstrated by numerical simulation.     

Real time observer and control scheme for a wind turbine system based on a high order sliding modes

The introduction of advanced control algorithms may improve considerably the efficiency of wind turbine systems. This work proposes a high order sliding mode (HOSM) control scheme based on the super twisting algorithm for regulating the wind turbine speed in order to obtain the maximum power from the wind. A robust aerodynamic torque observer, also based on the super twisting algorithm, is included in the control scheme in order to avoid the use of wind speed sensors. The presented robust control scheme ensures good performance under system uncertainties avoiding the chattering problem, which may appear in traditional sliding mode control schemes. The stability analysis of the proposed HOSM observer is provided by means of the Lyapunov stability theory. Experimental results show that the proposed control scheme, based on HOSM controller and observer, provides good performance and that this scheme is robust with respect to system uncertainties and external disturbances.     

Resilient event-triggered consensus control for nonlinear muti-agent systems with DoS attacks

The distributed event-triggered secure consensus control is discussed for multi-agent systems (MASs) subject to DoS attacks and controller gain variation. In order to reduce unnecessary network traffic in communication channel, a resilient distributed event-triggered scheme is adopted at each agent to decide whether the sampled signal should be transmitted or not. The event-triggered scheme in this paper can be applicable to MASs under denial-of-service (DoS) attacks. We assume the information of DoS attacks, such as the attack period and the consecutive attack duration, can be detected. Under the introduced communication scheme and the occurrence of DoS attacks, a new sufficient condition is achieved which can guarantee the security consensus performance of the established system model. Moreover, the explicit expressions of the triggering matrices and the controller gain are presented. Finally, simulation results are provided to verify the effectiveness of the obtained theoretical results.     

Event-triggered synchronization of delayed neural networks with actuator saturation using quantized measurements

This paper studies event-triggered synchronization control problem for delayed neural networks with quantization and actuator saturation. Firstly, in order to reduce the load of network meanwhile retain required performance of system, the event-triggered scheme is adopted to determine if the sampled signal will be transmitted to the quantizer. Secondly, a synchronization error model is constructed to describe the master-slave synchronization system with event-triggered scheme, quantization and input saturation in a unified framework. Thirdly, on the basis of Lyapunov–Krasovskii functional, sufficient conditions for stabilization are derived which can ensure synchronization of the master system and slave system; particularly, a co-designed parameters of controller and the corresponding event-triggered parameters are obtained under the above stability condition. Lastly, two numerical examples are employed to illustrate the effectiveness of the proposed approach.     

Adaptive quantized tracking control for a class of uncertain nonlinear systems with guaranteed transient performance

In this paper, an adaptive quantized control method with guaranteed transient performance is presented for a class of uncertain nonlinear systems. By introducing the Nussbaum function technique, the difficulty caused by quantization is handled and a novel adaptive control scheme is designed. In comparing with the existing adaptive control scheme, the key advantages of the proposed control scheme are that the controller needs no information about the parameters of the quantizer and the stability of the closed-loop system and the transient performance are independent of the coarseness of the quantizer. Based on Lyapunov stability theory and Barbalat’s Lemma, it is proven that all the signals in the resulting closed-loop system are bounded and the tracking error converges to zero asymptotically with the prescribed performance bound at all times. Simulation results are presented to verify the effectiveness of the proposed control method.