Output-relevant Variational autoencoder for Just-in-time soft sensor modeling with missing data

Main challenges for developing data-based models lie in the existence of high-dimensional and possibly missing observations that exist in stored data from industry process. Variational autoencoder (VAE) as one of the deep learning methods has been applied for extracting useful information or features from high-dimensional dataset. Considering that existing VAE is unsupervised, an output-relevant VAE is proposed for extracting output-relevant features in this work. By using correlation between process variables, different weight is correspondingly assigned to each input variable. With symmetric Kullback–Leibler (SKL) divergence, the similarity is evaluated between the stored samples and a query sample. According to the values of the SKL divergence, data relevant for modeling are selected. Subsequently, Gaussian process regression (GPR) is utilized to establish a model between the input and the corresponding output at the query sample. In addition, owing to the common existence of missing data in output data set, the parameters and missing data in the GPR are estimated simultaneously. A practical debutanizer industrial process is utilized to illustrate the effectiveness of the proposed method.     

基于软交换的NAT/防火墙穿透技术研究

通过对目前几种解决NAT(network addres stranslation)／防火墙穿逢方案的分析，提出了一种较易实现的穿透技术，并给出具体实现方案。     

Symmetric BEM formulations for 2-D steady-state and transit potential problems

This paper presents a new concept for symmetric boundary element method (SBEM) applicable to 2-D steady-state and transit potential problems. Two kinds of SBEM formulations are derived. Symmetry is obtained simply through matrix manipulation, and no hypersingularity appears. Therefore, SBEM is much easier than the traditional symmetric Galerkin BEM. Compared with the traditional asymmetric BEM, the present SBEM can reduce the computational cost for time domain problems only. However, when applied to BEM/FEM coupling procedure, SBEM can reduce the computational cost for both steady-state and time domain problems. Three numerical examples are included to illustrate the effectiveness and accuracy of the present formulations.     

用NAT技术实现负载均衡的实践

通过对路由器NAT功能配置实践,提出了使用反向NAT技术实现互联网访问负载均衡技术的一种解决方案.     

Symmetry properties and bifurcation analysis of a class of periodically forced chemical reactors

In this work, we discuss how periodic forcing may induce symmetry properties into mathematical models of chemical reactors. We define a class of reactors subjected to discontinuous periodic forcing, and show that all the reactors belonging to this class have spatio-temporal symmetry. This symmetry and its influence on the possible bifurcation scenarios are discussed. The bifurcation analysis is carried out with suitable discrete systems that exploit a property of the Poincaré map. In fact, it is shown that the spatio-temporal symmetry induced by the forcing makes the Poincaré map of the continuous system an iterate of another map. On this basis, a technique to implement parameter continuation methods is proposed. With such a technique, it is also possible to characterize symmetric and nonsymmetric regimes and unstable limit sets otherwise undetected with “bruteforce” approaches. Examples for reverseflow reactors and networks of n-reactors with periodically switched feed and discharge positions are presented.     

Synthesis of ordered polymers by direct polycondensation

A series of ordered polymers can be prepared by direct polycondensation of nonsymmetric monomers using diphenyl(2,3-dihydro-2-oxo-3-benzothiazolyl)phosphonate (1) as a condensing agent. The methodology and requirements for the preparation of ordered polymer are first presented. Then, the following ordered polymer syntheses are described: (1) ordered polyamides (head-to-head or tail-to-tail) from a symmetric monomer and a nonsymmetric monomer. (2) the ordered polyamide (head-to-tail) from a symmetric monomer and a nonsymmetric monomer. (3) the ordered (-abcd-) polymer from a pair of two symmetric monomers and a nonsymmetric monomer. (4) the ordered (-abcdef-) polymer from nonsymmetric monomers, XabX, YcdY, and ZefZ.     

Face recognition with Symmetric Local Graph Structure (SLGS)

Face recognition demonstrates the significant progress in the research field of biometric and computer vision. The fact is due to the current systems perform well under relatively control environments but tend to suffer when the present of variation in pose, illumination, and facial expression. In this work, a novel approach for face recognition called Symmetric Local Graph Structure (SLGS) is presented based on the Local Graph Structure (LGS). Each pixel is represented with a graph structure of its neighbours’ pixels. The histograms of the SLGS were used for recognition by using the nearest neighbour classifiers that include Euclidean distance, correlation coefficient and chi-square distance measures. AT&T and Yale face databases were used to be experimented with the proposed method. Extensive experiments on the face database clearly showed the superiority of the proposed approach over Local Binary Pattern (LBP) and LGS. The proposed SLGS is robust to variation in term of facial expressions, facial details, and illumination. Due to good performance of SLGS, it is expected that SLGS has a potential for application implementation in computer vision.     

UPnP基本原理以及在NAT中的应用

在互联网应用越来越丰富的情况下,设备之间如何通过UPn P方案实现互联互通显得日益重要,本文介绍了UPn P所定义的基本协议（如SSDP、GENA、SOAP等）,重点分析了UPn P实现的基本工作流程,并通过抓包工具捕获数据包,对各种流程传递的协议报文进行详尽分析,最后结合NAT技术,重点叙述UPn P在NAT技术中的应用。通过本文能够加深认识设备之间互联互通的一种方案。