Hong Kong Polytechnic University

About: Hong Kong Polytechnic University is a education organization based out in Hong Kong, China. It is known for research contribution in the topics: Tourism & Population. The organization has 29633 authors who have published 72136 publications receiving 1956312 citations. The organization is also known as: HKPU & PolyU.

Immobilization of polymeric g-C3N4 on structured ceramic foam for efficient visible light photocatalytic air purification with real indoor illumination.

Abstract: The immobilization of a photocatalyst on a proper support is pivotal for practical environmental applications. In this work, graphitic carbon nitride (g-C3N4) as a rising visible light photocatalyst was first immobilized on structured Al2O3 ceramic foam by a novel in situ approach. Immobilized g-C3N4 was applied for photocatalytic removal of 600 ppb level NO in air under real indoor illumination of an energy-saving lamp. The photocatalytic activity of immobilized g-C3N4 was gradually improved as the pyrolysis temperature was increased from 450 to 600 °C. The optimized conditions for g-C3N4 immobilization on Al2O3 supports can be achieved at 600 °C for 2 h. The NO removal ratio could reach up to 77.1%, exceeding that of other types of well-known immobilized photocatalysts. Immobilized g-C3N4 was stable in activity and can be used repeatedly without deactivation. The immobilization of g-C3N4 on Al2O3 ceramic foam was found to be firm enough to overwhelm the continuous air flowing, which can be ascribed to t...

Optimal Cloudlet Placement and User to Cloudlet Allocation in Wireless Metropolitan Area Networks

Abstract: Mobile applications are becoming increasingly computation-intensive, while the computing capability of portable mobile devices is limited. A powerful way to reduce the completion time of an application in a mobile device is to offload its tasks to nearby cloudlets, which consist of clusters of computers. Although there is a significant body of research in mobile cloudlet offloading technology, there has been very little attention paid to how cloudlets should be placed in a given network to optimize mobile application performance. In this paper we study cloudlet placement and mobile user allocation to the cloudlets in a wireless metropolitan area network (WMAN). We devise an algorithm for the problem, which enables the placement of the cloudlets at user dense regions of the WMAN, and assigns mobile users to the placed cloudlets while balancing their workload. We also conduct experiments through simulation. The simulation results indicate that the performance of the proposed algorithm is very promising.