小型自动化会议传声及控制系统研究

本文论述了一种小型的“自动化会议传声及控制系统”的结构、特点和实验数据。该系统具有“代表即席发言”、“主席优先发言”和两种语言的“同声传译”等功能,适合机关、团体、学校和企业单位的中小型会议厅使用,特别适宜需要多人即席发言、研讨问题和现场问答等类型的工作会议、学术报告、问题研讨和新闻发布等场合。实验结果表明,本设计方案具有良好的电声指标,而且具有结构简单、性能可靠和成本低廉等特点。

浅析空调系统噪声控制的若干问题

空调系统噪声主要来源于声源及二次噪声。其产生原因很多,涉及的因素也很广,但大体上可归纳为以下几方面:设计方面、施工方面、设备材料方面及运行管理方面。本文从设计角度,对空调系统噪声的控制进行简单的分析,提出适当的措施加以控制。

回转壳体中波传播特性研究的频率-波数谱法

基于快速傅里叶变换和最大熵谱法提出了一种频率 -波数谱法 ,并对某水下航行器尾部壳体的受激响应进行了分析 .运用这一有效方法 ,得到了振动波在该壳体中传播的波数、波速、波型和波的传播方向等重要信息 .针对壳体尾部模型的受激响应控制进行了试验研究 ,讨论了加强筋对振动传播的影响 .进一步用波动理论解释了加强筋的减振机理 .结果表明 ,采用当前的加筋方案对壳体结构的振动噪声控制。

Control Strategies and Mechanisms for Active Control of Sound Transmission into a Vibro-acoustic Enclosure

An analytical study was presented on active control of sound transmission into a vibro-acoustic enclosure comprising two flexible plates. Two types of actuators were used, i.e. acoustic actuator and distributed lead zirconate titanate piezoelectric (PZT) actuator instead of point force actuator. Using the modal acoustic transfer impedance-mobility matrices, the excitation and interaction in the coupled sound transmission system can be described with clear physical significance. With the control system designed to globally reduce the sound field, different control system configurations were considered, including the structural actuator on the incident plate, actuator on the receiving plate, acoustic actuator on the cavity, and their combinations. The effectiveness and performance of the control strategy corresponding to each system configuration were compared and discussed. The role and control mechanism of each type of actuator were of particular interest. It was shown that the incident plate actuator is effective in controlling the cavity-dominated modes and the structural modes dominated by the incident plate and receiving plate. Two main control mechanisms are involved in this control configuration, i.e., modal suppressing and modal rearrangement. For control system configuration with only acoustic actuator in the enclosure, the mechanism involved in this arrangement is purely modal suppression. Desirable placements of structural actuators in terms of total potential energy reduction were also discussed.

A mobile self-reconfigurable robot based on modularity

A novel mobile self-reconfigurable robot is presented. This robot consists of several independent units. Each unit is composed of modular components including ultrasonic sensor, camera, communication, computation, and mobility parts, and is capable of simple self-reconfiguring to enhance its mobility by expanding itself. Several units can not only link into a train or other shapes autonomously via camera and sensors to be a united whole robot for obstacle clearing, but also disjoin to be separate units under control after missions. To achieve small overall size, compact mechanical structures are adopted in modular components design, and a miniature advanced RISC machines （ARM） based embedded controller is developed for minimal power consumption and efficient global control. The docking experiment between two units has also been implemented.

Design and Analysis of a Gain-scaling Controller Applied to a Chain of Integrator System with Measurement Noise on Feedback Sensor

A control problem of a chain of integrator system with measurement noise on feedback sensor is considered. We propose a gain-scaling controller for compensating measurement noise of feedback sensor. Because control systems operate via feedback sensor＇s signal, the measurement noise in sensor＇ signal results in performance degradation or even system failure. Therefore, control systems often demand on compensating measurement noise. Our controller is equipped with a compensator and gain-scaling factor in order to reduce the effect of measurement noise on feedback sensor.

Controlled Quantum Teleportation Through Noisy GHZ Channel

In this paper, we propose two physical schemes for teleporting an unknown atomic state through noisy channel in cavity QED. The quantum channel is a noisy one -- a mixed GHZ state, which is more realistic in quantum information processing. We solve analytically a master equation in the Lindblad form with （L2,z, L3,z, L4,z）-type of noise in cavity Q, ED. A comparison between the two protocols are discussed.

Probabilistic multiparty-controlled teleportation of an arbitrary m-qubit state with a pure entangled quantum channel against collective noise

We present two general schemes for multiparty-controlled teleportation of an arbitrary m-qubit state against two types of collective noise by using m pure entangled states as the quantum channel.The first is used to control teleporting for an arbitrary m-qubit state against a collective-dephasing noise with nonmaximally entangled quantum channel,and the second is in teleporting the m-qubit state against the collective-rotation noise.The receiver can reconstruct the original state with an auxiliary qubit and the corresponding unitary operations if he cooperates with all the controllers.The scheme is optimal as the probability that the receiver reconstructs the original state equals to the entanglement of the quantum channel.