Nonlinear vector error tolerant interpolation of intermediate video images by weighted medians

The conversion of one video standard into another with different field and scan rates is a key feature for modern TV receivers and multimedia video equipment. Therefore, a new vector-based nonlinear conversion algorithm has been developed which applies nonlinear center weighted median (CWM) filters and yields a very good interpolation quality. One of the main properties of this algorithm is vector error tolerance. This property will be derived in this paper and its advantages will be shown. Assuming a 2-channel model of the human visual system with different spatio-temporal characteristics, there are contrary demands for the CWM filters. One can meet these demands by a vertical band separation and an application of the so-called temporally and spatially dominated CWMs. Hereby interpolation errors of the separated channels can be compensated by an adequate splitting of the spectrum. By this means, a very robust vector error tolerant upconversion method can be achieved which significantly improves the interpolation quality. By an appropriate choice of the CWM filter root structures main picture elements are interpolated correctly also if faulty vector fields occur. To demonstrate the correctness of the deduced interpolation scheme picture content is classified. These classes are distinguished by correct or incorrect vector assignment and correlated or noncorrelated picture content. The mode of operation of the new algorithm is portrayed for each class. Whereas for correlated picture content the mode of operation can be shown by object models the operation mode is shown for noncorrelated picture content by the output probability distribution function of the applied CWM filters. The new algorithm has been verified for a 100 Hz upconversion by objective evaluation methods and by comprehensive subjective test series. Within these tests for critical test sequences a gain of about 2 dB PSNR in the objective tests and about 0.4 evaluation grades in the subjective test series could be achieved.     

Image encryption using linear weighted fractional-order transform

As the linear weighted fractional-order Fourier transform (LWFRFT), an extension of the Fourier transform, has been widely studied, many linear weighted fractional-order transforms (LWFRTs) have been proposed consequently. Our research shows that the LWFRT has limitations when applied to image encryption. For example, its application to image encryption leads to the security risks of key invalidation. In this paper, we propose a new reformulation of the LWFRT which establishes the relation between many fractional-order transforms. With the help of the new reformulation, we point out the limitations of the LWFRT and analyze the reasons for key invalidation in image encryption. Finally, numerical simulation verifies our perspective.     

SIR-optimized weighted linear parallel interference canceller on fading channels

In this letter, we present a weighted linear parallel interference canceller (LPIC) where the multiple access interference (MAI) estimate in a stage is weighted by a factor before cancellation on Rayleigh fading and diversity channels. We obtain exact expressions for the average signal-to-interference ratio (SIR) at the output of the cancellation stages which we maximize to obtain the optimum weights for different stages. We also obtain closed-form expressions for the optimum weights for the different stages. We show that this SIR-optimized weighted LPIC scheme clearly outperforms both the matched filter (MF) detector as well as the conventional LPIC (where the weight is taken to be unity for all stages), in both near-far as well as non-near-far conditions on Rayleigh fading and diversity channels.     

基于加权IFS证据合成的多源信息融合方法

为权衡信息融合系统对各条证据的可信程度,提出基于直觉模糊交叉熵的证据折扣方法,用于直觉模糊证据合成规则。并根据确定性理论,对直觉模糊决策中的记分函数进行改进,得到基于确定性因子的记分函数形式,用于直觉模糊证据合成结果判定。最后通过与其他算法的对比实验,验证算法在多传感器目标识别应用中是有效的,且具有较高的计算效率。     

A linear weighted SIC multiuser detector with optimal weighting factor

In this paper, a linear weighted successive interference cancellation (SIC) detector is introduced to overcome the convergence issues of the conventional linear SIC detector. The latter converges to the decorrelator detector if it converges. The optimal weighting factor is derived using the steepest descent method. Simulation results show that if the optimal weighting factor is used, the convergence speed and thus the BER of the proposed structure can be significantly enhanced.     

基于相位差的伪线性加权最小二乘短基线定位

对辐射源进行无源定位是电子战领域的一个重要问题。针对短基线时差定位技术对时差测量精度要求很高的难题,提出了一种基于相位差的修正伪线性最小二乘算法。相较于非线性最小二乘法(NLS),修正伪线性最小二乘法的优势是可以得到目标位置表达式,不需要迭代运算,计算效率较高;不需要定位初值,避免了算法发散问题。理论分析和仿真均说明修正伪线性最小二乘法可用于短基线情况下的目标定位。     

Fuzzy combination of linear state-feedback and switching controllers

A fuzzy controller, which is a fuzzy combination of linear state-feedback and switching controllers, is proposed for nonlinear systems subject to parameter uncertainties. By proper design of the proposed fuzzy controller, the chattering effect near the origin can be eliminated. The global system stability is also guaranteed.     

Differential equation for a linear combination of variables in a linear multivariable system

An algebraic procedure is described for extracting the differential equation governing a linear combination of state variables in the vector-matrix differential equation dx/dt=Ax+Bu. Computations are based on Krylov's algorithm for reduction of a matrix to rational canonical form, and on the Gram determinant test for linear independence of a collection of vectors.     

嵌入式组合控制直线一级倒立摆系统

倒立摆系统广泛应用于对各种控制理论和控制策略的正确性和有效性的检验。针对固高公司直线一级倒立摆系统,提出一种嵌入式组合控制直线一级倒立摆系统。在线仿真实验表明,该系统达到了自动、安全的效果。分析系统响应曲线可知,嵌入式组合的控制算法正确、有效。     

Recognition of vector signals represented as a linear combination

Parallel recognition and estimation of all vector components of an input signal is shown to be possible if the standard vectors of the alphabet of classes constitute a basis and the input signal is a linear combination of noisy standard signals. The characteristics of the matrix filter intended to operate in the parallel recognition system have been obtained. The noise immunity of the system is investigated. An approach to the construction of characteristics ensuring error-free recognition is proposed.     

System identification using a linear combination of cumulant slices

A linear approach to identifying the parameters of a moving-average (MA) model from the statistics of the output is presented. First, it is shown that, under some constraints, the impulse response of the system can be expressed as a linear combination of cumulant slices. Then, this result is used to obtain a well-conditioned linear method for estimating the MA parameters of a nonGaussian process. The linear combination of slices used to compute the MA parameters can be constructed from different sets of cumulants of different orders, provided a general framework in which all the statistics can be combined. It is not necessary to use second-order statistics (autocorrelation slice), and therefore the proposed algorithm still provides consistent estimates in the presence of colored Gaussian noise. Another advantage of the method is that while most linear methods give totally erroneous estimates if the order is overestimated, the proposed approach does not require a previous estimation of the filter order. The simulation results confirm the good numerical conditioning of the algorithm and its improvement in performance in comparison to existing methods     

基于加权组合核RX算法异物检测及其参量选择

为了融合光谱形状差异信息和多项式核函数全局信息,充分挖掘地物特征,提高异常检测正确率,提出了一种加权组合核RX算法.该算法在高斯核函数的基础上,增加一个光谱角核函数.由于核函数参量和加权参量直接影响算法性能,分别采用了随机函数法、爬山法和粒子群算法对上述参量进行了选择.结果表明,在恒虚警率下使用粒子群算法进行参量设定得到的效果最好,且采用加权组合核函数RX算法得到的目标检测率为83.5%,相对于普通的核RX算法,正确率得到了提高.     

A generalized weighted linear predictor frequency estimation approach for a complex sinusoid

Based on linear prediction and weighted least squares, three simple iterative algorithms for frequency estimation of a complex sinusoid in additive white noise are devised. The proposed approach, which utilizes the first-order as well as higher order linear prediction terms simultaneously but does not require phase unwrapping, can be considered as a generalized version of the weighted linear predictor frequency estimator. In particular, convergence as well as mean and variance analysis of the most computationally efficient frequency estimator, namely, GWLP 2, are provided. Computer simulations are included to contrast the performance of the proposed algorithms with several conventional computationally attractive frequency estimators and Crame/spl acute/r-Rao lower bound for different frequencies, observation lengths, and signal-to-noise ratios.     

Causal AR modeling using a linear combination of cumulant slices

We address the problem of estimating the parameters of a pure AR causal model excited with non-Gaussian, ergodic, unobservable process. Output samples may be corrupted with colored Gaussian noise. Other types of noise are allowed provided that they have a set of mth order statistics whose value is zero, if the same set of statistics are different from zero for the signal. It is shown that each sample of the impulse response of the AR system that generates the process may be expressed as a linear combination of cumulant slices of any order, thus providing a new framework to combine cumulants of different orders. The resulting algorithm is shown to be well behaved and to provide consistent estimates while reducing the complexity significantly with respect to other approaches.     

Research on the measurement of CH4 concentration based on dual-band weighted combination model

A detection system based on supercontinuum laser absorption spectroscopy (SCLAS) technology was built up in this study. The absorption spectra of CH4 in different near-infrared bands were measured based on the SCLAS detection system. Under normal temperature and pressure, the absorption spectra of CH4 at different concentrations in the bands of 1 319—1 339 nm and 1 656—1 676 nm were measured. The linear models of CH4 concentrations in different bands were established. The fitting coefficient (R2) of the models were 0.995 7 and 0.996 1, respectively. In order to improve the concentration inversion ability of the model, the weight distribution of each model was determined by R2 and sum of squared error (SSE) to obtain a new combined model. The maximum relative error of the concentration inversion was reduced from 2.3% to 1.3%. The experimental results show the feasibility of applying the SCLAS technology to CH4 concentration measurement, and it also verifies that the dual-band combination model can improve the accuracy and stability of the CH4 concentration measurement.     

Generalized linear precoder and decoder design for MIMO channelsusing the weighted MMSE criterion

We address the problem of designing jointly optimum linear precoder and decoder for a MIMO channel possibly with delay-spread, using a weighted minimum mean-squared error (MMSE) criterion subject to a transmit power constraint. We show that the optimum linear precoder and decoder diagonalize the MIMO channel into eigen subchannels, for any set of error weights. Furthermore, we derive the optimum linear precoder and decoder as functions of the error weights and consider specialized designs based on specific choices of error weights. We show how to obtain: (1) the maximum information rate design; (2) QoS-based design (we show how to achieve any set of relative SNRs across the subchannels); and (3) the (unweighted) MMSE and equal-error design for fixed rate systems     

Scheduling algorithm for real-time imprecise computations tominimise maximum weighted errors using the linear programmingmethod

An optimal scheduling algorithm for imprecise systems is presented. The proposed algorithm aims at minimising the maximum weighted errors. A novel property of the algorithm is that the errors are evenly distributed among scheduled tasks. The complexity of the proposed algorithm is O(N³) in the worst case, where N is the number of tasks     

The universal opamp and applications in continuous-time resistorless and capacitorless linear weighted voltage addition

A versatile analog building block denoted the universal operational amplifier (opamp) is introduced. The circuit is a generalized version of the fully differential difference opamp with 2n weighted differential inputs. Applications in resistorless and capacitorless continuous-time linear weighted voltage addition are discussed. Experimental results of a test chip prototype are shown that validate the proposed approach. Simulations show potential for high frequency operation of the circuit with gain-bandwidth close to 140 MHz in 0.5-/spl mu/m CMOS technology.     

S.A.W. device reflectors weighted by combination of withdrawn and segmented lines

A technique for weighting surface acoustic wave (s.a.w.) device reflectors which combines withdrawal weighting and segmented lines is described. This scheme has the advantage of lower photolithographic mask costs through the partial use of withdrawal weighting, and the advantage of closely approximating the desired weighting function by partial use of segmented (dotted) lines. Effectiveness of this combined weighting technique is demonstrated by its use in sidelobe suppression in two-port s.a.w. resonators; however, combined-type weighted reflectors can be used to advantage in all types of filters utilising reflective arrays.