Abstract:
In this work we propose a centrality measure for networks, which we refer to as Laplacian centrality, that provides a general framework for the centrality of a vertex based on the idea that the importance (or centrality) of a vertex is related to the ability of the network to respond to the deactivation or removal of that vertex from the network. In particular, the Laplacian centrality of a vertex is defined as the relative drop of Laplacian energy caused by the deactivation of this vertex. The Laplacian energy of network Gwith nvertices is defined as , where is the eigenvalue of the Laplacian matrix of G. Other dynamics based measures such as that of Masuda and Kori and PageRank compute the importance of a node by analyzing the way paths pass through a node while our measure captures this information as well as the way these paths are “redistributed” when the node is deleted. The validity and robustness of this new measure are illustrated on two different terrorist social network data sets and 84 networks in James Moody’s Add Health in school friendship nomination data, and is compared with other standard centrality measures.

Abstract:
Given the problems in intelligent gearbox diagnosis methods, it is difficult to obtain the desired information and a large enough sample size to study; therefore, we propose the application of various methods for gearbox fault diagnosis, including wavelet lifting, a support vector machine (SVM) and rule-based reasoning (RBR). In a complex field environment, it is less likely for machines to have the same fault; moreover, the fault features can also vary. Therefore, a SVM could be used for the initial diagnosis. First, gearbox vibration signals were processed with wavelet packet decomposition, and the signal energy coefficients of each frequency band were extracted and used as input feature vectors in SVM for normal and faulty pattern recognition. Second, precision analysis using wavelet lifting could successfully filter out the noisy signals while maintaining the impulse characteristics of the fault; thus effectively extracting the fault frequency of the machine. Lastly, the knowledge base was built based on the field rules summarized by experts to identify the detailed fault type. Results have shown that SVM is a powerful tool to accomplish gearbox fault pattern recognition when the sample size is small, whereas the wavelet lifting scheme can effectively extract fault features, and rule-based reasoning can be used to identify the detailed fault type. Therefore, a method that combines SVM, wavelet lifting and rule-based reasoning ensures effective gearbox fault diagnosis.

Manufacturing accuracy, especially position
accuracy of fastener holes, directly affects service life and security of aircraft.
The traditional modification has poor robustness, while the modification based on
laser tracker costs too much. To improve the relative position accuracy of aircraft
assembly drilling, and ensure the hole-edge distance requirement, a method was presented
to modify the coordinates of drilling holes. Based on online inspecting two positions
of pre-assembly holes and their theoretical coordinates, the spatial coordinate
transformation matrix of modification could be calculated. Thus the straight drilling
holes could be modified. The method improves relative position accuracy of drilling
on simple structure effectively. And it reduces the requirement of absolute position
accuracy and the cost of position modification. And the process technician also
can use this method to decide the position accuracy of different pre-assembly holes
based on the accuracy requirement of assembly holes.

Abstract:
Let $A$ be a $d$-dimensional local ring containing a field. We will prove that the highest Lyubeznik number $\lambda_{d,d}(A)$ (defined in \cite{l1}) is equal to the number of connected components of the Hochster-Huneke graph (defined in \cite{hh}) associated to $B$, where $B=\hat{\hat{A}^{sh}}$ is the completion of the strict Henselization of the completion of $A$. This was proven by Lyubeznik in characteristic $p>0$. Our statement and proof are characteristic-free.

Abstract:
In this paper we study the commutativity of the Frobenius functor and the colon operation of two ideals for Noetherian rings of positive characteristic $p$. New characterizations of regular rings and local UFDs are given.

Abstract:
Let $X$ be an arbitrary projective scheme over a field $k$. Let $A$ be the local ring at the vertex of the affine cone for some embedding $\iota: X\hookrightarrow \mathbb{P}^n_k$. G. Lyubeznik asked (in \cite{l2}) whether the integers $\lambda_{i,j}(A)$ (defined in \cite{l1}), called the Lyubeznik numbers of $A$, depend only on $X$, but not on the embedding. In this paper, we make a big step toward a positive answer to this question by proving that in positive characteristic, for a fixed $X$, the Lyubezink numbers $\lambda_{i,j}(A)$ of the local ring $A$, can only achieve finitely many possible values under all choices of embeddings.

Abstract:
Let $R=k[x_1,\dots,x_n]/I$ be a standard graded $k$-algebra where $k$ is a field of prime characteristic and let $J$ be a homogeneous ideal in $R$. Denote $(x_1,\dots,x_n)$ by $\mathfrak{m}$. We prove that there is a constant $C$ (independent of $e$) such that the regularity of $H^s_{\mathfrak{m}}(R/J^{[p^e]})$ is bounded above by $Cp^e$ for all $e\geq 1$ and all integers $s$ such that $s+1$ is at least the dimension of the locus where $R/J$ doesn't have finite projective dimension.

Abstract:
Let $X$ be a projective scheme over a field $k$ and let $A$ be the local ring at the vertex of the affine cone of $X$ under some embedding $X\hookrightarrow\mathbb{P}^n_k$. We prove that, when $\ch(k)>0$, the Lyubeznik numbers $\lambda_{i,j}(A)$ are intrinsic numerical invariants of $X$, i.e., $\lambda_{i,j}(A)$ depend only on $X$, but not on the embedding.

By rigidizing the input joints, all
possible combinations of drive selecting for the 4-PPPS parallel mechanism are
analyzed based on the screw theory in this paper, and the five of them are
proved to be reasonable. Then choosing the one as mechanical actuators, the
workspace of the 4-PPPS parallel mechanism is deduced according to the rational
input scheme. Finally the rationality of input scheme for this mechanism is
identified on the basis of the continuity of the workspace.

Abstract:
In this paper, the fully discrete orthogonal collocation method for
Sobolev equations is
considered, and the equivalence for discrete Garlerkin method is proved.Optimal
order error estimate is obtained.