SUMMARYThe past decade has witnessed a growing interest in vehicular networking. Initially motivated by traffic safety, vehicles equipped with computing, communication and sensing capabilities will be organized into ubiquitous and pervasive networks with a significant Internet presence while on the move. Large amount of data can be generated, collected, and processed on the vehicular networks. Big data on vehicular networks include useful and sensitive information which could be exploited by malicious intruders. But intrusion detection in vehicular networks is challenging because of its unique features of vehicular networks: short range wireless communication, large amount of nodes, and high mobility of nodes. Traditional methods are hard to detect intrusion in such sophisticated environment, especially when the attack pattern is unknown, therefore, it can result unacceptable false negative error rates. As a novel attempt, the main goal of this research is to apply data mining methodology to recognize known attacks and uncover unknown attacks in vehicular networks. We are the first to attempt to adapt data mining method for intrusion detection in vehicular networks. The main contributions include: 1) specially design a decentralized vehicle networks that provide scalable communication and data availability about network status; 2) applying two data mining models to show feasibility of automated intrusion detection system in vehicular networks; 3) find the detection patterns of unknown intrusions. key words: vehicular networks, mobile networks, intrusion detection, vehicular ad hoc network, security

Ultralow thermal conductivity materials have triggered much interest due to diverse applications in thermal insulation, thermal barrier coating, and especially thermoelectrics. Two dimensional (2D) indium tellurides with ultralow thermal conductivity provide a versatile platform for tailoring the heat transfer, exploring new candidates for thermoelectrics, and achieving miniature, lightweight, and highly integrated devices. Unfortunately, their nanostructure and structure‐related heat transfer properties at a 2D scale are much less studied due to difficulties in material fabrication. The ionic character between interlayers and strong covalent bonds in 3D directions impede the anisotropic growth of indium telluride flakes; meanwhile, the low environmental stability and chemical reactivity of tellurium also limit the fabrication of high‐quality tellurides, thus hindering the exploration of thermal transport properties. Here, a self‐modulation‐guided growth strategy to synthesize high‐quality 2D In4Te3 single crystals with ultralow thermal conductivity (0.47 W m−1 K−1) is developed. This strategy can also be extended to synthesize a series of highly crystallized metal tellurides, providing excellent candidates for further application in thermoelectrics.

Tip-assisted lithography is a technique full of potential for nanofabrication and data storage, allowing for nanofabrication within several nanometers using the heated nanotip. Thus, the knowledge of the instantaneous thermal response of the nanotip under the laser heating is important for temperature control. In this work, a prototype of an ultrafast thermal probing method for the apex of a silicon nanotip has been achieved. Instead of obtaining an average thermal response over the entire nanotip, the temperature and thermal stress in the confined apex region of the nanotip were successfully measured in picosecond duration. Furthermore, to understand the heat transfer process in the nanotip, comparative studies were conducted on a silicon micro-cantilever and a silicon wafer, respectively. Experiment-based simulation further revealed that the equivalent thermal conductivity of the nanotip is ∼35 W/(m•K), substantiating the reduction in the thermal conductivity of nanomaterials due to the size effect. Both nonuniform laser absorption and heat transfer deterioration in the nanotip contribute to the nonuniform temperature distribution, thermal stress, and thermal deformation. This work is expected to provide important insights into the thermal response of the nanotip and an effective way for fast thermal characterization of nanomaterials.

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