Time filter

Source Type

Xiamen, China

Xiamen University of Technology is a provincial public university located in Xiamen, Fujian province, China. Wikipedia.

Hong C.,Xiamen University of Technology | Zhu J.,Zhejiang University
Neurocomputing | Year: 2013

Content-based image retrieval (CBIR) always suffers from the so-called semantic gap. Query-By-Multiple-Examples (QBME) is introduced to bridge it and applied in a lot of CBIR systems. However, current QBME methods usually query with each example separately and combine the query results. In this way, the computational time will increase linearly with the growing number of query examples. In this paper, we propose a novel QBME method for fast image retrieval based on transductive learning framework. To improve the speed of QBME, we introduce two improvements. First, we explore the semantic correlations of image data in the training process. These correlations are learned using sparse representation. With the semantic correlations, semantic correlation hypergraph (SCHG) is constructed to model the images and their correlations. The construction of SCHG is free of any parameter. After constructing SCHG, we predict the ranking values of images by using the pre-learned semantic correlations. Second, we propose a multiple probing strategy to rank the images with multiple query examples. Different from traditional QBME methods which accept one input example at a time, all the input examples are processed at the same time in this strategy. The experimental results demonstrate the effectiveness of the proposed method on both retrieval performance and speed. © 2012 Elsevier B.V. Source

Xu J.,Xiamen University of Technology
International Journal of Heat and Technology | Year: 2015

Having the premise of the certain acoustic performance, a muffler should make the pressure loss as small as possible. A simulation model of a fork truck muffler with a complex structure is established. Based on the finite volume method, multi-dimensional numerical simulation regarding velocity field and pressure field of steady flows for a muffler is performed using CFD (computational fluid dynamic method). Flow characteristics and pressure distribution of the muffler are analyzed. It is found that the vortex inside the muffler creates a great pressure loss. With the increases of inlet gas flow rate, the pressure loss of the muffler increases gradually. The internal structure of the muffler is redesigned for obtaining the optimized structure on the basis of analysis. The influences of the inner tube length on the flow and pressure loss of muffler are researched. The study will provide a theoretical basis for designing a complex muffler. Source

Liu C.,Xiamen University of Technology
Ocean Engineering | Year: 2016

A novel wave energy converter (UREWEC), which is constructed by attaching a U-tube to a traditional oscillating water column WEC, is proposed. To improve the performance of the UREWEC at lower wave frequencies, the two sides of the U-tube are sloped. A mathematical model based on potential theory is used to examine the wave energy extraction efficiency of the UREWEC. The analytical results show that the wave energy extraction efficiency of the UREWEC can reach 100% at the optimal frequency if the viscosity and nonlinearity are ignored. The optimal frequency of the UREWEC can be instantaneously adjusted by controlling the amount of the fluid in the U-tube and the turbine rotational speed. The sloped sides of the U-tube are beneficial to obtain a lower UREWEC optimal frequency. A smaller cross-sectional area of the U-tube can extend the adjusted ranges of the optimal frequency while increasing the wall-friction losses. © 2016 Elsevier Ltd. Source

Zuo J.,Xiamen University of Technology
Applied Surface Science | Year: 2010

Ag nanostructures on TiO2 films were deposited by RF magnetron sputtering under variable deposition parameters, such as DC potential, RF-power and total pressure. The concentration, shape, and distribution of the deposited nanostructures and continuous Ag films on thin films of TiO2 can be tailored by careful variation of the deposition parameters. Controllable clusterlike, islandlike and film Ag structures on TiO2 film were obtained, respectively. DC potential was found as an appropriate parameter to tailor the change of Ag nanostructure and the overall Ag amount. The compositions, nanostructures and morphologies of nanocomposite films appreciably influence the optical response. © 2010 Elsevier B.V. Source

Tang D.,Xiamen University of Technology
Differential Geometry and its Application | Year: 2011

In this paper, we study a new non-Riemannian quantity H defined by the S-curvature. We find that the non-Riemannian quantity is closely related to S-curvature. We characterize Randers metrics of almost isotropic S-curvature if and only if they have almost vanishing H-curvature. Furthermore, the Randers metrics actually have zero S-curvature if and only if they have vanishing H-curvature. © 2010 Elsevier B.V. Source

Discover hidden collaborations