Improvement of the prediction performance of a soft sensor model based on support vector regression for production of ultra-low sulfur diesel

A novel data-driven, soft sensor based on support vector regression （SVR） integrated with a data compression technique was developed to predict the product quality for the hydrodesulfurization （HDS） process. A wide range of experimental data was taken from a HDS setup to train and test the SVR model. Hyper-parameter tuning is one of the main challenges to improve predictive accuracy of the SVR model. Therefore, a hybrid approach using a combination of genetic algorithm （GA） and sequential quadratic programming （SQP） methods （GA-SQP） was developed. Performance of different optimization algorithms including GA-SQP, GA, pattern search （PS）, and grid search （GS） indicated that the best average absolute relative error （AARE）, squared correlation coefficient （R2）, and computation time （CT） （AARE = 0.0745, R2 = 0.997 and CT = 56 s） was accomplished by the hybrid algorithm. Moreover, to reduce the CT and improve the accuracy of the SVR model, the vector quantization （VQ） technique was used. The results also showed that the VQ technique can decrease the training time and improve prediction performance of the SVR model. The proposed method can provide a robust, soft sensor in a wide range of sulfur contents with good accuracy.

SMALL PERTURBATION CRAMER METHODS AND MODERATE DEVIATIONS FOR MARKOV PROCESSES

This paper presents a small perturbation Cramer method for obtaining the large deviation principle of a family of measures (β,ε> 0) on a topological vector space. As an application, we obtain the moderate deviation estimations for uniformly ergodic Markov processes.

A FAST SEARCH METHOD BASED ON THE STATISTICAL PROPERTIES OF SIGNAL

The concepts of ordered code-book and the priority of code-vector are proposedin this paper.The statistical properties of a signal are investigated through its coded sequence.Experimental results are presented which provide some insight into the statistical properties ofvector quantized sequences.Based on the given concepts and experimental results,a fast searchmethod for the vector quantization of correlated information sources,such as Gauss-Markovsources,is proposed and has shown its efficiency in simulation results.

A New Vector Markov Process for M/G/1 Queue

In this paper, by considering the stochastic proces s of the busy period and the idle period, and introducing the unfinished work as a supplementary variable, a new vector Markov process was presented to study th e M/G/1 queue again. Through establishing and solving the density evolution equa tions, the busy-period distribution, and the stationary distributions of waitin g time and queue length were obtained. In addition, the stability condition of th is queue system was given by means of an imbedded renewal process.

Mathematical Apparatus for Selection of Optimal Parameters of Technical, Technological Systems and Materials Based on Vector Optimization

We presented Mathematical apparatus of the choice of optimum parameters of technical, technological systems and materials on the basis of vector optimization. We have considered the formulation and solution of three types of tasks presented below. First, the problem of selecting the optimal parameters of technical systems depending on the functional characteristics of the system. Secondly, the problem of selecting the optimal parameters of the process depending on the technological characteristics of the process. Third, the problem of choosing the optimal structure of the material depending on the functional characteristics of this material. The statement of all problems is made in the form of vector problems of mathematical (nonlinear) programming. The theory and the principle of optimality of the solution of vector tasks it is explained in work of https://rdcu.be/bhZ8i. The implementation of the methodology is shown on a numerical example of the choice of optimum parameters of the technical, technological systems and materials. On the basis of mathematical methods of solution of vector problems we developed the software in the MATLAB system. The numerical example includes: input data (requirement specification) for modeling;transformation of mathematical models with uncertainty to the model under certainty;acceptance of an optimal solution with equivalent criteria (the solution of numerical model);acceptance of an optimal solution with the given priority of criterion.

Fast direction of arrival algorithm based on vector-sensor arrays using wideband sources

An acoustic vector sensor(AVS)can capture more information than a conventional acoustic pressure sensor(APS).As a result,more output channels are required when multiple AVS are formed into arrays,making processing the data stream computationally intense.This paper proposes a new algorithm based on the propagator method for wideband coherent sources that eliminates eigen-decomposition in order to reduce the computational burden.Data from simulations and lake trials showed that the new algorithm is valid:it resolves coherent sources,breaks left/right ambiguity,and allows inter element spacing to exceed a half-wavelength.

基于视觉信息加工的草原公路行车安全性分析

为探究草原公路各典型行车环境驾驶人视觉信息加工模式的差异性,从视觉层面解析草原公路行车安全,基于眼动仪开展草原公路实车实验,提取驾驶人在自由行驶、跟驰、对向来车、后车切入、路侧风险、交叉口6种真实行车环境下的眼动数据。首先,从视觉分配和视觉搜索两个维度构建评价指标体系,采用动态聚类法将驾驶人的视觉兴趣区域划分为5类,将信息熵与马尔可夫链平稳分布理论结合,构建视点分布信息熵量化驾驶人视觉注意分配的复杂度,并引入扫视幅度、扫视速度分析驾驶人对视觉信息的搜索过程。最后,构建基于CRITIC法的加权秩和比评价模型,对不同行车环境下驾驶人的视觉信息加工强度进行了综合评价。结果显示:驾驶人的视点分布在不同行车环境中存在差异,但当前车道始终是驾驶人获取视觉信息的主视区;各视觉评价指标随行车环境的变化呈显著的统计学差异;驾驶人遇到路侧风险时的视觉信息加工强度最大,行车安全性相对更低。

基于Markov决策过程用交叉熵方法优化软件测试

研究了待测软件某些参数已知的条件下,以最小化平均测试费用为目标的软件测试优化问题.将软件测试过程处理成马尔可夫(Markov)决策过程,给出了软件测试的马尔可夫决策模型,运用交叉熵方法,通过一种学习策略获得软件测试的最优测试剖面,用于优化软件测试.模拟结果表明,学习策略给出的测试剖面要优于随机测试策略,检测和排除相同数目的软件缺陷,学习策略比随机测试能够显著地减少测试用例数,降低测试成本,提高缺陷检测效率.

基于连续隐Markov模型的发酵过程关键状态变量软测量

针对生物发酵过程中一些关键状态变量难以用仪表进行在线检测的问题,提出了一种基于连续隐Markov模型(CHMM)的软测量方法.首先,为增加模型预测的鲁棒性,采用多观测样本序列训练CHMM模型库,运用Baum-Welch参数重估修正公式实现CHMM参数优化;然后,将新样本观测向量输入训练好的CHMM模型库,并基于Viterbi算法计算新样本在模型库中各个CHMM内的输出概率;最后,通过加权平均运算得出软测量结果.将所提出的方法应用于红霉素发酵过程菌体质量浓度软测量,并进行了建模与仿真研究.结果表明:所建CHMM软测量模型能够很好地用于生物发酵过程菌体质量浓度值预测,且预测效果优于人工神经网络软测量模型.

基于Markov过程和伪极坐标快速傅里叶变换的重采样篡改检测

针对图像中的重采样篡改操作导致的离散余弦变换(DCT)系数之间相关性的变化,提出了一种新的图像重采样篡改检测方法。首先,提取Markov特征,利用高阶统计量分析重采样图像中离散余弦变换系数之间的关系;然后,将图像所在的笛卡儿坐标映射到伪极坐标(Pseudo-Polar)轴上提取图像的光滑度作为纹理特征,利用纹理特征检测图像的重采样操作;最后,将提取的两类特征输入到支持向量机(SVM)中训练和分类,从而检测出图像中的重采样篡改操作。实验结果表明:所提方法可以检测出图像中的重采样篡改操作,并具有较好的检测率,且对于一定范围内的加噪处理也具有鲁棒性。

移动机器人Markov定位算法的研究——方向传感器建模新方法

为了改善移动机器人Markov定位算法中方向传感器模型的性能,提出基于高斯函数的新概率模型.该模型考虑了方向角周期性问题,对相位进行了转换,利用高斯函数对方向传感器进行了概率建模.将此模型放入Markov算法,与其他传感器组成观测模型,并进行对称环境中的单次定位仿真和复杂环境中的连续定位仿真.仿真结果表明,这种概率模型计算量小,收敛速度快,在大量测量噪声存在下工作稳定.

基于阶次小波包与Markov链模型的转子早期故障诊断

针对转子启动过程中振动信号表现为非平稳、非高斯特征及传统诊断方法精度不高的现状,将阶次小波包和Markov链模型引入转子的早期故障诊断中,提出了一种新的自适应故障诊断模型。首先利用阶次跟踪算法对瞬态振动信号重采样,得到等角度分布诊断信号;其次采用小波包对该信号分解——重构,提取其在各频带的能量特征向量,通过Markov链模型对其进行预测;最后通过故障实例验证,结果表明:将阶次小波包变换和Markov链模型相结合进行故障诊断是可行而有效的。

一类Markov过程的最大绝对值过程概率密度求解的新方法

随机过程或随机系统响应的最大绝对值概率分布往往是科学与工程中关心的重要挑战性问题.本文从理论与数值上进行了Markov过程的时变最大绝对值过程及其概率分布研究.文中,通过引入扩展状态向量,构造了最大绝对值-状态量联合向量过程,由此将不具有Markov性的最大值过程转化为具有Markov性的向量随机过程.在此基础上,通过最大绝对值-状态量之间的关系,建立了联合向量过程的转移概率密度函数.进而,结合Chapman-Kolmogorov方程和路径积分方法,提出了最大绝对值概率密度函数求解的数值方法.由此,可以得到Markov过程最大绝对值过程的时变概率密度函数,可进一步用于结构动力可靠度分析等.通过数值算例,验证了本文所提方法的有效性.该方法有望推广到更一般随机系统的极值分布估计之中.

SAR图像小波域隐Markov模型中状态参数的Turbo迭代估计

利用小波域隐Markov模型能够有效地改善合成孔径雷达(SAR)图像信息提取的效果,而乘性斑点噪声影响下的隐状态的估计是其中的关键问题,目前该问题还没有得到有效地解决.借用信息论领域中的Turbo迭代译码原理,针对SAR图像信号,提出一种新的隐状态的Turbo迭代估计方法.该方法在两个不相关的子空间上分别采用不同的约束条件对隐状态进行轮流地估计,并将其后验概率作为一种外信息进行交换.实验结果证明该方法具有优良的估计结果,并且收敛速度较快.

SOFM和HMM在矢量量化码本优化中的应用

在语音压缩编码中，矢量量化占有很大比重和计算量。码本的好坏与方法的选择有很大关系。将基于神经网络的ＳＯＦＭ（自组织特征映射算法）和ＨＭＭ（隐含马尔可夫过程）应用于矢量量化，从而产生更为优良的码本。

Markov调制的随机时滞系统的条件稳定性

用比较方法讨论了Markov调制的随机时滞系统的条件弱随机稳定性,并给出了一个应用实例.

Robust H_∞ Control for Uncertain Markovian Jump Linear Time-Delay Systems

This paper studies the robust stochastic stabilization and robust H∞ control for linear time-delay systems with both Markovian jump parameters and unknown norm-bounded parameter uncertainties. This problem can be solved on the basis of stochastic Lyapunov approach and linear matrix inequality (LMI) technique. Sufficient conditions for the existence of stochastic stabilization and robust H∞ state feedback controller are presented in terms of a set of solutions of coupled LMIs. Finally, a numerical example is included to demonstrate the practicability of the proposed methods.

明渠弯道边界层的Markov特性研究

针对明渠弯道湍流边界层,利用一阶Markov过程并结合象限分析法,计算了转化模式的转化概率。结果指出各象限平均自转化概率为65.51%,76.98%,69.42%,76.97%,湍流猝发的喷射和清扫发生频率最高;自转化概率P22、P44沿河宽周期性向凸岸衰减,并在弯顶凹岸处达到最大值,其随着底部环流的增大有微弱减小,但总体分布于67%～90%。

Modeling and inferring 2.1D sketch with mixed Markov random field

This paper presents a method of computing a 2.1D sketch (i.e., layered image representation) from a single image with mixed Markov random field (MRF) under the Bayesian framework. Our model consists of three layers: the input image layer, the graphical representation layer of the computed 2D atomic regions and 3-degree junctions (such as T or arrow junctions), and the 2.1D sketch layer. There are two types of vertices in the graphical representation of the 2D entities: (i) regions, which act as the vertices found in traditional MRF, and (ii) address variables assigned to the terminators decomposed from the 3-degree junctions, which are a new type of vertices for the mixed MRF. We formulate the inference problem as computing the 2.1D sketch from the 2D graphical representation under the Bayesian framework, which consists of two components: (i) region layering/coloring based on the Swendsen-Wang cuts algorithm, which infers partial occluding order of regions, and (ii) address variable assignments based on Gibbs sampling, which completes the open bonds of the terminators of the 3-degree junctions. The proposed method is tested on the D-Order dataset, the Berkeley segmentation dataset and the Stanford 3D dataset. The experimental results show the efficiency and robustness of our approach. © 2017 Beijing Institute of Aerospace Information.

Analysis of DAR(1)/D/s Queue with Quasi-Negative Binomial-II as Marginal Distribution

In this paper we consider the arrival process of a multiserver queue governed by a discrete autoregressive process of order 1 [DAR(1)] with Quasi-Negative Binomial Distribution-II as the marginal distribution. This discrete time multiserver queueing system with autoregressive arrivals is more suitable for modeling the Asynchronous Transfer Mode(ATM) multiplexer queue with Variable Bit Rate (VBR) coded teleconference traffic. DAR(1) is described by a few parameters and it is easy to match the probability distribution and the decay rate of the autocorrelation function with those of measured real traffic. For this queueing system we obtained the stationary distribution of the system size and the waiting time distribution of an arbitrary packet with the help of matrix analytic methods and the theory of Markov regenerative processes. Also we consider negative binomial distribution, generalized Poisson distribution, Borel-Tanner distribution defined by Frank and Melvin(1960) and zero truncated generalized Poisson distribution as the special cases of Quasi-Negative Binomial Distribution-II. Finally, we developed computer programmes for the simulation and empirical study of the effect of autocorrelation function of input traffic on the stationary distribution of the system size as well as waiting time of an arbitrary packet. The model is applied to a real data of number of customers waiting for checkout in an airport and it is established that the model well suits this data.