CCD类成像器件的噪声研究

CCD图像传感器的输出信号是空间采样的离散模拟信号,其中夹杂着各种噪声和干扰。对CCD信号进行处理的目的就是在不损失图像细节的前提下,尽可能地消除噪声和干扰,以提高信噪比,获取高质量的图像。为此,必须对CCD的噪声种类和特性有所了解,并针对各种噪声进行相应的去噪处理。所以对CCD成像器件噪声部分的研究,有利于提高CCD成像器件的分辨率,也能提高探测微弱光的能力。     

CHIP: Collaborative Host Identity Protocol with Efficient Key Establishment for Constrained Devices in Internet of Things

Wireless Personal Communications - The Internet of Things (IoT) is the next evolutionary paradigm of networking technologies that interconnects almost all the smart objects and intelligent sensors...     

利用GIS技术实现有线电视用户地址的可视化管理

1 前 言 用户地址在有线电视用户信息管理中占有极其重要的地位。以往由于地址错误使我们在对用户故障进行维修时,不能快速、准确地找到用户居住的位置,给有线电视的维修工作带来诸多不便,因为地址不详也给催缴收视费带来了很多麻烦,每年都有很大数目的收视费不能被及时收缴上来,给有线电视运营单位造成了很大的经济损失。为了更有效地对有线电视用户进行管理,解决有线电视收费难的问题,笔者在此提出一种利用地理信息系统(GIS)技术对用户地址进行地理编码,实现用户地址可视化管理的方案。该方案已在《大连有线电视     

IPv4地址不足解决方案综述

IPv4地址不足的问题日益严重,业界主要有两条解决路径:一是非兼容方式的升位,这就是采用全新的IP地址协议,如IPv6;另外一条路径是采用兼容方式的路径,如NAT(网络地址转换)技术、SuIP(超级协议)技术.文章对IPv6,NAT以及SuIP等三种技术的优势和不足进行了分析,然后对这三种技术进行了比较,最后展望了这三种解决方案的发展前景.     

Constrained Capacities for Faster-Than-Nyquist Signaling

This paper deals with capacity computations of faster-than-Nyquist (FTN) signaling. It shows that the capacity of FTN is higher than the orthogonal pulse linear modulation capacity for all pulse shapes except the sinc. FTN signals can in fact achieve the ultimate capacity for the signal power spectral density (PSD). The paper lower- and upper-bounds the FTN capacity under the constraint of finite input alphabet. It is often higher than the capacity for comparable orthogonal pulse systems; sometimes it is superior to all forms of orthogonal signaling with the same PSD.      

Constrained feeds for limited scan arrays

Lossless modular hybrid coupled networks are described for application to phased arrays requiring a few beamwidths of scan. The simplest example of these networks for symmetrical limited scan is easily synthesized from analytical expressions which involve one parameter-the allowed grating lobe level. Formulas and design curves are presented for engineering applications. A practical example is calculated and compared with the conventional discrete subarray approach. Worst case radiation patterns are shown to provide the desired performance. The results show that the present technique in its simplest form requires only about half the number of phase shifters, drivers, and beam steering active devices as a conventional discrete subarray system which provides the same grating lobe level.     

免疫计算在求解约束优化问题中的应用

介绍了约束条件的函数优化的主要问题及处理约束的解决方法，针对一般性非线性规划问题，采用免疫算法来进行处理。具体方法是：首先引入罚函数构造新的目标函数，而后运用免疫算法进行求解。通过测试表明，算法收到较好的效果。     

电子百科

码分多址（CDMA）;蜂窝式移动电话系统;手机TV-OUT;     

Constrained band selection for hyperspectral imagery

Constrained energy minimization (CEM) has shown effective in hyperspectral target detection. It linearly constrains a desired target signature while minimizing interfering effects caused by other unknown signatures. This paper explores this idea for band selection and develops a new approach to band selection, referred to as constrained band selection (CBS) for hyperspectral imagery. It interprets a band image as a desired target signature vector while considering other band images as unknown signature vectors. As a result, the proposed CBS using the concept of the CEM to linearly constrain a band image, while also minimizing band correlation or dependence provided by other band images, is referred to as CEM-CBS. Four different criteria referred to as Band Correlation Minimization (BCM), Band Correlation Constraint (BCC), Band Dependence Constraint (BDC), and Band Dependence Minimization (BDM) are derived for CEM-CBS.. Since dimensionality resulting from conversion of a band image to a vector may be huge, the CEM-CBS is further reinterpreted as linearly constrained minimum variance (LCMV)-based CBS by constraining a band image as a matrix where the same four criteria, BCM, BCC, BDC, and BDM, can be also used for LCMV-CBS. In order to determine the number of bands required to select p, a recently developed concept, called virtual dimensionality, is used to estimate the p. Once the p is determined, a set of p desired bands can be selected by the CEM/LCMV-CBS. Finally, experiments are conducted to substantiate the proposed CEM/LCMV-CBS four criteria, BCM, BCC, BDC, and BDM, in comparison with variance-based band selection, information divergence-based band selection, and uniform band selection.     

每月新品

MCU/DSP/CPU英特尔至强处理器5400系列/双核英特尔至强处理器5200系列英特尔宣布推出面向嵌入式市场的全新处理器(具有长达7年的生命周期支持)、芯片组及电信级服务器。新款处理器基于高k金属栅极晶体管技术,并采用先进的45nm制程工艺,具体产品包括四核英特尔至强处理器5400系列和双核英特尔至强处理器5200系列。     

微电子封装业和微电子封装设备

介绍了国际和国内半导体封装业的发展情况及几种新颖封装,指出中国即将成为国际半导体封装产业的重要基地之一,这为我国发展半导体封装设备提供了良好的市场前景,例举了有关半导体封装工艺、检测、试验及支撑所需的设备。     

Construction of Constrained Codes for State-Independent Decoding

Constrained sequence codes are widely used to meet constraints imposed by digital storage and communication systems. This paper develops an algorithm for the construction of constrained codes that admit state-independent decoding. By partitioning the code into a group of alphabets, one for each state, a codebook is developed using this algorithm that will allow the code to be decoded at the receiver without the need for state information. Finally, we use this algorithm to construct DCfree runlength-limited (RLL) codes, and we present two highly efficient state-independent decodable DC-free RLL codes.     

Constrained likelihood function for a uniform array

The symmetry of a uniform linear array can be exploited to construct a simplified analytical representation for the maximum likelihood function. This results in a significant decrease in the computational load and allows the algorithm to be used with large arrays     

Nonparametric Combinatorial Regression for Shape Constrained Modeling

We introduce a unified approach for calculating nonparametric shape constrained regression. Enforcement of the shape constraint often accounts for the impact of a physical phenomenon or a specific property. It also improves the model's predicability and facilitates subsequent optimizations. The regression models are built by transforming the problem into the combinatorial domain where the shape constraints are imposed by bounding the combinatorial search space. We start by addressing isotonicity shape constraint using a dynamic programming algorithm and demonstrate how the problem can be mapped to the graph combinatorics domain. Next we show how a number of other important shape constraints including unimodality, convexity, limited level set, and limited slope can be addressed using the same framework. The flexibility of proposed framework enables solving the shape constrained regression problem with an arbitrary user-defined error metric. This flexibility is exploited to add robustness against outliers to the model. The algorithms are described in detail and their computational complexity is established. The performance and effectiveness of the shape constrained regression is evaluated on traces of temperature and humidity measurements from a deployed sensor network where a high degree of accuracy and robustness is demonstrated.      

平面阵约束自适应单脉冲测角算法

单脉冲测角技术原理简单且易于工程实现,被广泛应用于各类雷达系统中,但在近主瓣干扰环境下,采用常规自适应波束形成技术会导致单脉冲鉴角曲线产生畸变,严重影响雷达测角性能。针对此问题,本文提出一种适于二维面阵的约束自适应单脉冲测角方法,将多约束自适应方向图保形技术与广义单脉冲测角技术相结合,实现干扰环境下的目标角误差估计。仿真实验表明,该方法能够在抑制近主瓣干扰的同时,基本保持理想单脉冲鉴角曲线,大幅提升雷达在未知干扰环境下的角误差估计性能,从而实现目标稳定跟踪。     

求解约束优化的一种新的进化算法

罚函数法是解决约束优化最常用的方法,但如何确定罚因子是其难以克服与回避的问题.该文提出的求解约束优化问题的新的进化算法克服了这一困难,其基本思想是对种群中的个体按可行和不可行分别采取两种评价方案,对可行解按其目标函数值的大小加以评价,对不可行解按其违反约束的程度进行评价.作为评价个体优劣的适应度函数将可行点映射到(-1,1),将不可行点映射到(1,2),这样有效地区分了可行点与不可行点.数据实验与比较结果表明了该算法的有效性.     

一种最小长度约束的EMD包络拟合方法

 经典经验模态分解(Empirical Mode Decomposition,EMD)采用三次样条插值方法进行包络拟和,存在较严重的"过冲"现象。在研究该问题已有方法基础上,提出了一种基于最小长度约束的包络拟合方法,以包络曲线长度最小为目标函数,采用Lagrange求极小值法优化极值点处的导数值,然后采用分段三次Hermite函数插值方法进行包络拟合,得到平滑包络线.实验表明该方法能有效地克服三次样条插值法的"过冲"现象和分段抛物线插值法的人为弯折现象,能拟合出更平滑的包络线,使得EMD分解更准确,有效改善模态混淆问题.     

OFDM系统的受限隐马尔可夫模型

本文采用隐马尔可夫模型(HMM)的一种特例--受限隐马尔可夫模型(CHMM)对正交频分复用(OFDM)系统进行建模,给出了CHMM参数估计算法的改进,可避免计算机编程实现时出现下溢导致的计算失败.通过仿真讨论了CHMM状态数的选取问题,并给出了HIPERLAN/2室内无线信道环境下OFDM系统的一组CHMM,该模型可用于比较不同编码方案的性能或者分析高层协议性能.     

Constrained optimisation technique for general array patternsynthesis

A new technique for controlling the sidelobe level for general array pattern synthesis is presented. The basic idea is to introduce a weighting function to the performance index based on the integral of the power response over the sidelobe regions. This function more heavily weights the array power response further away from the mainlobe, so that in the minimisation of the integral of the weighted power response over the sidelobe regions, very low sidelobes can be achieved. The resulting beam pattern is highly directional. Numerical results show that the proposed technique is very effective for general array geometry sidelobe control design