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Hao J.,5 South Zhongguancun Street | Yan Y.,Beijing Institute of Technology | Gong L.,Beijing Institute of Technology | Wang G.,Beijing Institute of Technology | Lin J.,Beijing Institute of Technology
Decision Support Systems | Year: 2014

The exponential growth of available information and the deployment of knowledge management systems delivers excessive information to the end users that they cannot manage at once. This problem has led to an increased emphasis on solutions to information overload. Searching and browsing are two methods to locate information. Many studies have focused on solving the information overload problem in the searching process, but the methods to alleviate information overload in browsing process have not been adequately studied. Hence, a method that addresses information overload in the browsing process is presented in this paper. The aim is to reduce the information overload during browsing domain knowledge for new knowledge users who have little understanding of the information. In this method, a knowledge map and social network analysis are utilized to navigate the knowledge users. Technologies first construct a knowledge map from text mining and the important knowledge that includes more information about the domain is then identified via social network analysis. Based on this process, the knowledge user can browse the domain knowledge starting from the important knowledge and navigate via the knowledge map. We applied the method to assist new knowledge users in browsing the Computer Numerical Control (CNC) domain knowledge base to validate the method. The results indicate that the method can identify the important knowledge at a highly acceptable level, the constructed knowledge map can efficiently navigate the knowledge users, and the information overload can be significantly decreased.© 2014 Elsevier B.V. All rights reserved.

Liu R.-Q.,5 South Zhongguancun Street | Jiang Y.,5 South Zhongguancun Street
Advanced Materials Research | Year: 2014

Rocket engine thrust is the main performance parameters. The flow field of missile fight in different Mach is simulated by using FLUENT, then calculating the thrust of different conditions. The calculating results are consistent with the theory of Mach almost no effect on the thrust. © (2014) Trans Tech Publications, Switzerland.

Yang J.,5 South Zhongguancun Street | Yang L.,5 South Zhongguancun Street
Lecture Notes in Electrical Engineering | Year: 2012

An improved linear network coding algorithm is proposed which breaks through the limitation of polynomial-time algorithm for multicasting application in wireless or cyclic networks. Examples show that the algorithm can increase channel utilization by exploiting the broadcasting character of wireless channels. Moreover, it could be implemented in a cyclic network directly. © 2012 Springer-Verlag GmbH.

Cheng Z.,5 South Zhongguancun Street | Wang F.,5 South Zhongguancun Street | Ma Z.,5 South Zhongguancun Street
Applied Mechanics and Materials | Year: 2012

Nanometer Al2O3-13%wtTiO2 wear-resistant coating was prepared by The plasma spraying process, and the coating was tested through a SRV friction and wear testing machine, the worn surface and wear debris were observed by scanning electron microscopy, and the wear mechanism was analyzed. The friction coefficient of Nanometer Al2O 3-13%wtTiO2 decreases with the increase of the load. The main wear mechanism is adhesive wear, accompanied by a small amount of abrasive wear. © (2012) Trans Tech Publications.

Ding H.,5 South Zhongguancun Street | Cheng Z.,5 South Zhongguancun Street | Rong H.,5 South Zhongguancun Street | Lu L.,5 South Zhongguancun Street
Applied Mechanics and Materials | Year: 2012

Nano-structured Al2O3-13%TiO2 coating was deposited by air plasma spraying. Wear properties of the coatings under different load trough SRV friction and wear testing machine were studied, the results showed that wear mass loss of Al2O3-13%TiO2 coating by plasma spraying slide with ZrO2 and Si3N4 increase with load increasing, but the difference is that wear loss of coaing slide with Si3N4 is lower than the coating slide with ZrO2 when load is less than 40N. Opposite phenomenon will occur when load is higher than 40N.The wear surface morphology was analyzed trough scanning electron microscopic, the results showed that coating slided with Si3N4 ball when matching at low loads, with a shallow furrow shape grinding. There were wide and deep furrows while at higher loads. Coating slide with ZrO2 ball has no obvious cracks, no layer spalling.Wear was occurred by micro cutting. © (2012) Trans Tech Publications, Switzerland.

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