Zhejiang Gongshang University

About: Zhejiang Gongshang University is a education organization based out in Hangzhou, China. It is known for research contribution in the topics: Computer science & Chemistry. The organization has 8258 authors who have published 7670 publications receiving 90296 citations. The organization is also known as: Zhèjiāng Gōngshāng Dàxué.

Deep learning-based tree classification using mobile LiDAR data

Abstract: Our work addresses the problem of extracting and classifying tree species from mobile LiDAR data. The work includes tree preprocessing and tree classification. In tree preprocessing, voxel-based upward-growing filtering is proposed to remove ground points from the mobile LiDAR data, followed by a tree segmentation that extracts individual trees via Euclidean distance clustering and voxel-based normalized cut segmentation. In tree classification, first, a waveform representation is developed to model geometric structures of trees. Then, deep learning techniques are used to generate high-level feature abstractions of the trees’ waveform representations. Quantitative analysis shows that our algorithm achieves an overall accuracy of 86.1% and a kappa coefficient of 0.8 in classifying urban tree species using mobile LiDAR data. Comparative experiments demonstrate that the uses of waveform representation and deep Boltzmann machines contribute to the improvement of classification accuracies of tree species.

Microstructure and performance of Z-scheme photocatalyst of silver phosphate modified by MWCNTs and Cr-doped SrTiO3 for malachite green degradation

Abstract: Visible-light-driven photocatalysis as a promising technology has recently attracted great attention in environmental remediation. In this work, novel Z-scheme heterojunction photocatalysts Ag3PO4@MWCNTs@Cr:SrTiO3 with excellent visible-light-driven photocatalytic performance and photostability were successfully synthesized and characterized. The photocatalytic activity for malachite green (MG) degradation was measured, and photodegradation mechanisms were investigated using GC–MS, ESR, and radical trapping experiments. On consideration of the practical applications, the effects of coexisting ions and pH were also evaluated. Results showed that significant changes of crystal size and micro-morphology for Ag3PO4 were observed before and after the addition of MWCNTs, which transformed from a polyhedron with a diameter of about 30 μm into a spherical-like crystal with a diameter of 0.28–0.69 μm. This phenomenon was reported for the first time. The optimal catalyst with a dosage of 100 mg/g (the mass ratio of pollutant to photocatalyst) could reach 100% MG removal in 6 and 10 min under natural solar radiation and visible light irradiation, respectively. Results from the radical trapping experiments and ESR analysis confirmed that there existed the Z-scheme transfer mechanisms, and O2− and h+ played an important role during the photocatalytic degradation. Several small molecular organic acids such as acetic acid, glyoxylic acid, fumaric acid and benzoic acid were detected by GC–MS in the photodegradation products of MG, which further indicates that photocatalytic degradation pathway involved N-demethylation, benzene removal and open-ring reactions. The performance of the photocatalyst would be inhibited under strong acid condition or at the coexistence of certain concentration of Cr6+ and Cl−. The novel addition of MWCNTs in the preparation and the changes of crystal structure and properties for the photocatalysts have the potential to promote the application of the photocatalysts for environmental remediation.

Intrusion Detection in Cyber-Physical Systems: Techniques and Challenges

Abstract: Cyber-physical systems (CPSs) integrate the computation with physical processes. Embedded computers and networks monitor and control the physical processes, usually with feedback loops where physical processes affect computations and vice versa. CPS was identified as one of the eight research priority areas in the August 2007 report of the President's Council of Advisors on Science and Technology, as CPS will be the core component of many critical infrastructures and industrial control systems in the near future. However, a variety of random failures and cyber attacks exist in CPS, which greatly restrict their growth. Fortunately, an intrusion detection mechanism could take effect for protecting CPS. When a misbehavior is found by the intrusion detector, the appropriate action can be taken immediately so that any harm to the system will be minimized. As CPSs are yet to be defined universally, the application of the instruction detection mechanism remain open presently. As a result, the effort will be made to discuss how to appropriately apply the intrusion detection mechanism to CPS in this paper. By examining the unique properties of CPS, it intends to define the specific requirements first. Then, the design outline of the intrusion detection mechanism in CPS is introduced in terms of the layers of system and specific detection techniques. Finally, some significant research problems are identified for enlightening the subsequent studies.