Dalian University of Technology

About: Dalian University of Technology is a education organization based out in Dalian, China. It is known for research contribution in the topics: Catalysis & Finite element method. The organization has 60890 authors who have published 71921 publications receiving 1188356 citations. The organization is also known as: Dàlián Lǐgōng Dàxué.

Linearized Alternating Direction Method with Adaptive Penalty for Low-Rank Representation

Abstract: Low-rank representation (LRR) is an effective method for subspace clustering and has found wide applications in computer vision and machine learning. The existing LRR solver is based on the alternating direction method (ADM). It suffers from $O(n^3)$ computation complexity due to the matrix-matrix multiplications and matrix inversions, even if partial SVD is used. Moreover, introducing auxiliary variables also slows down the convergence. Such a heavy computation load prevents LRR from large scale applications. In this paper, we generalize ADM by linearizing the quadratic penalty term and allowing the penalty to change adaptively. We also propose a novel rule to update the penalty such that the convergence is fast. With our linearized ADM with adaptive penalty (LADMAP) method, it is unnecessary to introduce auxiliary variables and invert matrices. The matrix-matrix multiplications are further alleviated by using the skinny SVD representation technique. As a result, we arrive at an algorithm for LRR with complexity $O(rn^2)$, where $r$ is the rank of the representation matrix. Numerical experiments verify that for LRR our LADMAP method is much faster than state-of-the-art algorithms. Although we only present the results on LRR, LADMAP actually can be applied to solving more general convex programs.

Nano-core effect in nano-engineered cementitious composites

Abstract: Nanoscale impact can bring big changes in micro-meso-macroscale behaviors of the composites. The addition of nano fillers makes cementitious materials stronger, more durable and multifunctional/smart. This paper aims at investigating the underlying mechanism for understanding and controlling the nano-engineered cementitious composites. The nano-core effect is proposed through integrating core-effect with nano effect, and is proved by experimental evidences for the cementitious composites with different nano fillers. The nano-core effect is closely relative to the intrinsic properties of nano fillers, composition and processing of the cementitious composites. The behaviors of the nano-engineered cementitious composites are governed by nano-core effect zone, i.e. nano-core-shell element. It is therefore concluded that the nano-core effect is fundamental for design, fabrication and application of the nano-engineered cementitious composites.

The Structure of Scientific Collaboration Networks in Scientometrics

Abstract: The structure of scientific collaboration networks in scientometrics is investigated at the level of individuals by using bibliographic data of all papers published in the international journal Scientometrics retrieved from the Science Citation Index (SCI) of the years 1978–2004. Combined analysis of social network analysis (SNA), co-occurrence analysis, cluster analysis and frequency analysis of words is explored to reveal: (1) The microstructure of the collaboration network on scientists’ aspects of scientometrics; (2) The major collaborative fields of the whole network and of different collaborative sub-networks; (3) The collaborative center of the collaboration network in scientometrics.