Parallel concatenated convolutional codes from linear systems theory viewpoint

The aim of this work is to characterize two models of concatenated convolutional codes based on the theory of linear systems. The problem we consider can be viewed as the study of composite linear system from the classical control theory or as the interconnection from the behavioral system viewpoint. In this paper we provide an input–state–output representation of both models and introduce some conditions for such representations to be both controllable and observable. We also introduce a lower bound on their free distances and the column distances.     

Dynamic allocation for input redundant control systems

In this paper we address control systems with redundant actuators and characterize the concepts of weak and strong input redundancy. Based on this characterization, we propose a dynamic augmentation to a control scheme which performs the plant input allocation with the goal of employing each actuator in a suitable way, based on its magnitude and rate limits. The proposed theory is first developed for redundant plants without saturation and then extended to the case of magnitude saturation first and of magnitude and rate saturation next. Several simulation examples illustrate the proposed technique and show its advantages for practical application.     

Finite-time consensus of Markov jumping multi-agent systems with time-varying actuator faults and input saturation

This paper gives attention to the issue of finite-time leader-following consensus of nonlinear discrete-time multi-agent systems with Markov jump parameters. A robust fault-tolerant control protocol that takes the effect of time-varying actuator faults and actuator saturation into account is considered for the addressed system. The main purpose of the paper is to design a fault-tolerant controller such that the leader-following consensus of the addressed system is achieved over a prescribed finite-time interval. By using the Lyapunov functional approach, Abel’s lemma and some properties of Kronecker product, a sufficient condition for the existence of fault-tolerant state feedback controller for the addressed system is presented and an explicit parameterization of such a controller is obtained. Eventually, a numerical example along with its simulation results is exploited to reflect the applicability of the proposed design method, wherein the robust performance of controller is exhibited despite the presence of actuator saturation and time-varying actuator faults.     

超宽带通信中模拟空时码的一种子空间检测方法

该文针对应用于超宽带(UWB)通信中的模拟空时码, 提出了一种基于子空间的盲检测方法。在接收端不需要估计信道,利用信号子空间和噪声子空间正交的性质,建立了一个二次型,最小化该二次型就可得到发送信号的估计。平坦衰落信道环境中的仿真表明,子空间方法能够实现和相关接收相同的分集增益;当多个连续的空时码联合解码时,其性能优于现有的非相关解码方法。     

焦平面输入电路研究

在混合式焦平面阵列中,探测器和读出电路的耦合通过输入级电路实现。为分析输入电路对探测器-放大器系统性能的影响,用分立元件设计制作了一个三级的前置放大器并进行了模拟实验,实验表明放大器输入级噪声是造成探测器信噪比下降的主要因素,应用中应该选用具有特定噪声性能的放大器与探测器匹配。研究了焦平面中常用的直接注入(DI)和电容反馈放大电路(CTIA)与探测器耦合时在噪声、输入阻抗、工作点匹配等方面应具备的条件。提出了临界输入阻抗的概念,实验表明,当电路的输入阻抗低于此临界值时(对于GaN p?蛳i?蛳n 光伏探测器来说约为106 Ω),焦平面才能获得较高的注入效率。     

具有输入知识的高维数据聚类算法研究

针对目前聚类算法没有充分地利用输入知识,不便于知识的学习和增长的情形,提出在高维数据集的情况下,恰当地利用输入知识可以更准确有效地发现聚类,提出聚类的相关维集的概念,分析输入知识的特点,对带有输入知识的高维聚类算法进行研究,指导聚类的学习过程。     

降低碘耗的途径

碘盐生产过程中碘酸钾的添加系统、碘酸钾添加控制办法与碘酸钾的添加稳定性,对于保证碘盐合格率、降低生产成本有重要影响。本文从这三个方面进行分析,以期对从事加碘工作的同行有所帮助。     

A probabilistic damage identification approach for structures with uncertainties under unknown input

To avoid the false positives of damages in the deterministic identification method induced by uncertainties in measurement noise, a probabilistic method is proposed to identify damages of the structures with uncertainties under unknown input. The proposed probabilistic method is developed from a deterministic simultaneous identification method of structural physical parameters and input based on dynamic response sensitivity. The deterministic simultaneous identification method is first derived. The effect of uncertainties caused by measurement noise on the identified parameters is then investigated. The statistical parameters of the identified structural parameters are calculated. The damage index is derived from the statistical parameters of the physical parameters of intact and damaged structure. The probability of identified damage, defined as the probability of identified structural stiffness smaller than that of intact structure, is further derived using the probability method. A twelve-story building and a nine-bay three-dimensional frame structure are, respectively, analyzed numerically and experimentally using the proposed method. The research results indicate that the probabilistic simultaneous identification method for damage and input can decrease the false positives of damages in contrast with the deterministic method under intensive measurement noise, and it can also achieve an accurate identification for structural unknown input.     

语音录入系统在针织成品检验中的应用

介绍纺织面料成品检验语音输入系统的方案设计,通过语音识别与合成技术构建语音录入系统,通过自适应学习提高识别效率。阐述通过成品检验环境噪音测试、验布工人声音采集建立语音系统,以及该系统在语音验布上的应用。经过应用测试显示,使用语音系统代替手写录入可使疵点检验率从57%提升到73%。在针织成品检验中采用语音录入系统能够快速录入疵点信息,提高检验效率,进一步简化验布工操作流程,降低漏验和堵布风险,提高面料整体的质量控制能力。