非方广义系统带最坏干扰抑制的奇异LQ问题

研究了非方广义系统带最坏干扰抑制的奇异线性二次指标最优控制问题(即LQ问题).在给定的条件下,最坏干扰和最优控制—状态对均存在且惟一,最优控制可被综合为状态反馈.在最坏干扰和最优控制作用下,所得闭环系统的任意有限特征值均在开左半复平面,且闭环系统的状态有最少自由元.     

支持向量学习并行区域增长结合活动轮廓模型的图像分割算法

为克服经典区域增长算法门限设置困难和图像分割精度不高的问题,提出了基于支持向量机学习的区域增长与活动轮廓模型结合的高精度图像分割算法。首先交互式选择属于目标区域的子块和背景区域的子块形成支持向量机的训练样本;并利用这些已知的训练样本训练支持向量分类器。在目标与背景的并行竞争增长过程中,利用训练好的支持向量分类器(SVC)进行分类判决,得到目标对象的初始轮廓。为提高分割对象的精度,采用活动轮廓模型获得准确的边缘。仿真实验获得了较好的分割效果,表明该提出的算法是合理可行的。     

Artificial Neural Network That Can Say “Unknown”

A new artificial neural network that can reject strange patterns is presented. The new network is an improved version of the RCE network. Each cell in the last layer of the present network has two thresholds. The new threshold produces the smallest boundary that encloses all examples associated with the cell in the pattern vector space. The present network can reject strange patterns by using this boundary. The rejection of strange patterns in the present and RCE networks was investigated by practical experiments using digits sampled from X-ray films of the human chest.     

Fourier transform raman spectroscopy using a bench-top fourier transform infrared spectrometer

The use of a bench top FTIR spectrometer for near infrared Fourier transform Raman spectroscopy is demonstrated. The use of near infrared excitation results in fluorescence free Raman spectra allowing previously difficult samples to be measured.     

Active suppression of narrowband noises in 3D sound fields

This paper presents a simple multiple-input-multiple-output (MIMO) controller for active suppression of narrowband noise in 3D sound fields. The controller only depends on a complex matrix H(jω₀) instead of an n × n transfer matrix to model the secondary paths. Unlike other available ANCs that obtain the controller transfer functions by adaptation, the proposed one solves its controller transfer matrix directly from H(jω₀); and tolerates some degrees of errors in H(jω₀). If necessary, the proposed system may be made adaptive to trace the drifting secondary path. Online identification of a matrix H(jω₀) is easier than that of a transfer matrix with many coefficient matrices. The estimate would be more accurate for H(jω₀) if other conditions remain the same. The proposed scheme can be modified to suppress narrowband noises with multiple bands by a moderate increase in complexity.     

Bio‐inspired method to fabricate poly‐dopamine/reduced graphene oxide composite membranes for dyes and heavy metal ion removal

Due to the narrow layer spacing, graphene oxide (GO) composite membrane usually exhibits a relatively low water flux in the process of wastewater treatment. In this study, GO was reduced to reduced graphene oxide through a bio‐inspired method, which was functionalized modified by poly‐dopamine (PDA). Then a series of PDA/reduced graphene oxide sheet films were prepared by vacuum filtration on the surface of cellulose acetate membrane (under the pressure of −0.1 MPa). The result indicated that the novel membranes had an excellent stability owing to the cross‐link of PDA. In addition, the hydrophilicity of membrane was increased significantly after PDA modification, which presented a superior water flux than pure GO composite membrane. More importantly, as‐prepared membranes were successfully applied for the removal of dyes (including Congo red, methylene blue, and rhodamine B) and heavy mental ion (Cu(II)) from simulated wastewater. This work might provide a new method for preparation and application of GO composite membranes.     

空间激光通信移动平台的自抗扰视轴稳定控制

分析空间激光通信移动平台角运动和框架偏转之间的速度耦合关系,给出克服移动平台角运动的视轴稳定方法,针对视轴稳定系统中存在的非线性、多干扰问题,应用自抗扰控制法对三轴视轴稳定系统进行分散独立控制,采用模糊理论对自抗扰控制器的相关参量进行自整定.仿真和模拟实验表明:在1Hz条件下,相对于参量辨识控制法,模糊自抗扰控制法的抗扰动隔离度提高了7.4dB;在模拟扫频实验条件下,将1~2Hz与2~4Hz的扰动实验区间进行比较,模糊自抗扰控制法的抗扰动隔离度下降仅2.2dB.模糊自抗扰控制具有较好的快速响应性、较小的超调和频率适应性,能够满足系统稳态准确度的要求,并能克服平台角运动耦合、不确定性扰动问题.     

面向MEMS加速度传感器的仪表放大器的设计与实现

加速度传感器已经广泛应用于军事、工业、环境监测等领域，已经成为热点的研究对象，但是器件的小型化与可靠性成为限制该技术发展的重要瓶颈。因此，针对新型硅基MEMS 加速度传感器的信号处理电路小型化的问题，提出了一种与MEMS技术完全兼容基于CMOS工艺的片上集成运算放大器电路。通过提取分析相关加速度传感器的性能参数，设计低功耗、低噪声且符合精度等特殊要求的前置放大器。同时对集成仪表放大器的主要电路特性和功耗进行了仿真分析。从仿真结果看，设计的三运放仪表放大器的关键参数—共模抑制比可以到达101dB，整体性能良好。完成了对仿真结果的版图设计和验证，继而在华润上华0.5μm CMOS标准工艺线上进行了流片，完成了芯片的封装测试，该测试结果显示运放的增益能够达到42dB，功耗仅为5.25mW，符合预期的设计目标。     

Ultrasound Imaging of Treatment-Needed Cardiac Rejection with CD4-Targeted Nanobubbles

Acute cardiac allograft rejection (ACAR) is one of the main reasons for mortality after heart transplantation. The timely diagnosis of treatment-needed ACAR is of great importance in the clinic. Molecular imaging may make accurate diagnoses at the early stage to visualize the activity of specific pathological processes. The amount of CD4⁺-lymphocyte infiltration is a crucial index in ACAR grading. CD4-targeted nanobubbles (NB_CD4) are fabricated to assess the infiltrating CD4⁺ lymphocytes, while isotype control nanobubbles (NB_Iso) are also fabricated. Animal models with ACAR grades from 0R to 3R are established. Ultrasound molecular imaging (USMI) is performed to distinguish different rejection grades with NB_CD4. In the grade 2R and 3R groups, the USMI signals of NB_CD4 are significantly higher than those of NB_Iso. The signals of NB_CD4 in the 2R group are significantly lower than those in the 3R group and significantly higher than those in the 1R and 0R groups. Moreover, the signals of NB_CD4 are strongly correlated with the rejection grades and the number of infiltrating CD4⁺ lymphocytes. As asymptomatic rejection with 2R or higher grades should be seriously treated, USMI with NB_CD4 may be a new approach to timely diagnosis of treatment-needed ACAR.     

Order acceptance and scheduling: A taxonomy and review

Over the past 20 years, the topic of order acceptance has attracted considerable attention from those who study scheduling and those who practice it. In a firm that strives to align its functions so that profit is maximized, the coordination of capacity with demand may require that business sometimes be turned away. In particular, there is a trade-off between the revenue brought in by a particular order, and all of its associated costs of processing. The present study focuses on the body of research that approaches this trade-off by considering two decisions: which orders to accept for processing, and how to schedule them. This paper presents a taxonomy and a review of this literature, catalogs its contributions and suggests opportunities for future research in this area.