A multi-point collaborative DDoS defense mechanism for IIoT environment

Nowadays,a large number of intelligent devices involved in the Industrial Internet of Things(IIoT)environment are posing unprecedented cybersecurity challenges.Due to the limited budget for security protection,the IIoT devices are vulnerable and easily compromised to launch Distributed Denial-of-Service(DDoS)attacks,resulting in disastrous results.Unfortunately,considering the particularity of the IIoT environment,most of the defense solutions in traditional networks cannot be directly applied to IIoT with acceptable security performance.Therefore,in this work,we propose a multi-point collaborative defense mechanism against DDoS attacks for IIoT.Specifically,for the single point DDoS defense,we design an edge-centric mechanism termed EdgeDefense for the detection,identification,classification,and mitigation of DDoS attacks and the generation of defense information.For the practical multi-point scenario,we propose a collaborative defense model against DDoS attacks to securely share the defense information across the network through the blockchain.Besides,a fast defense information sharing mechanism is designed to reduce the delay of defense information sharing and provide a responsive cybersecurity guarantee.The simulation results indicate that the identification and classification performance of the two machine learning models designed for EdgeDefense are better than those of the state-of-the-art baseline models,and therefore EdgeDefense can defend against DDoS attacks effectively.The results also verify that the proposed fast sharing mechanism can reduce the propagation delay of the defense information blocks effectively,thereby improving the responsiveness of the multi-point collaborative DDoS defense.

Photocatalytic degradation of sulfadiazine in suspensions of TiO_(2)nanosheets with exposed(001)facets

Antibiotics such as sulfonamides are widely used in agriculture as growth promoters and medicine in treatment of infectious diseases.However,the release of these antibiotics has caused serious environmental problems.In this paper,photocatalytic oxidation technology was used to degrade sulfadiazine(SDZ),one of the typical sulfonamides antibiotics,in UV illuminated TiO_(2)suspensions.It was found that TiO_(2)nanosheets(TiO_(2)-NSs)with exposed(001)facets exhibit much higher photoreactivity towards SDZ degradation compared to TiO_(2)nanoparticles(TiO_(2)-NPs)with a rate constant increases from0.017 min^(-1)to 0.035 min^(-1),improving by a factor of 2.1.Under the attacking of reactive oxygen species(ROSs)such as superoxide radicals(*O_(2)^(-))and hydroxyl radicals(*OH),SDZ was steady degraded on the surface of TiO_(2)-NSs.Based on the identification of the produced intermediates by LC–MS/MS,possible degradation pathways of SDZ,which include desulfonation,oxidation and cleavage,were put forwards.After UV irradiation for 4 h,nearly 90%of the total organic carbon(TOC)can be removed in suspensions of TiO_(2)-NSs,indicating the mineralization of SDZ.TiO_(2)-NSs also exhibits excellent stability in photocatalytic degradation of SDZ in wide range of pH.Even after recycling used for 7 times,more than 91.3%of the SDZ can be efficiently removed,indicating that they are promising to be practically used in treatment of wastewater containing antibiotics.