| 1. |
- Cao, Rihong, et al.
(författare)
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Failure mechanism of non-persistent jointed rock-like specimens under uniaxial loading : Laboratory testing
- 2020
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Ingår i: International Journal of Rock Mechanics And Mining Sciences. - : Elsevier. - 1365-1609 .- 1873-4545. ; 132
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Tidskriftsartikel (refereegranskat)abstract
- It is generally known that discontinuities have a remarkable influence on the mechanical behaviour of rock masses. To further understand the fracture mechanisms of jointed rock masses, substantial effort has been focused on the strength anisotropy and failure characteristics of rocks/rock-like specimens containing persistent joints with different geometric parameters. However, only a few laboratory tests have considered the failure mechanism of a rock mass with 3D joints, especially for non-persistent joints with different persistence levels. In the present work, experiments on cubic rock-like specimens containing non-persistent joints (in areal extent) subjected to uniaxial compression were conducted to further investigate the influence of the joint inclination (θ) and persistence (N) on the rock mechanical properties and failure characteristics. The strength of a 3D non-persistent jointed specimen is characterized by three stages as the joint inclination angle (θ) increases from 0° to 90°. The strength of jointed specimens decreases with increasing N for all θ values, with the highest strength obtained for N = 0.42 and the lowest strength recorded for N = 0.92. Based on CT scan results, four typical fracture modes were identified: splitting, splitting + sliding, sliding, and intact failure. Overall, as the joint inclination increases, the failure mode of the specimen transforms from splitting to sliding and then to the intact failure mode. However, with decreasing joint persistence, the failure modes of some specimens will change from sliding to mixed failure (splitting + sliding).
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| 2. |
- Li, Yuhong, et al.
(författare)
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Distance Assisted Information Dissemination with Broadcast Suppression for ICN-based VANET
- 2016
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Konferensbidrag (refereegranskat)abstract
- Information-centric networking (ICN) is being applied to the vehicular networks by more and more researchers on account of its lightweight and connectionless networking paradigm and in-network caching characteristics, making it suitable for the dynamic environments of vehicular networks. However, wireless transmission of interest packets to find content in the network may lead to broadcast storms that can affect the performance of information dissemination severely. This paper proposes a distance assisted data dissemination method with broadcast storm suppressing mechanism (DASB) for supporting rapid and efficient information dissemination in ICN-based vehicular ad hoc networks (VANETs). Geo-position data of vehicles are used to accelerate packet forwarding, and vehicular nodes in certain areas are restricted to forward packets in order to suppress the broadcast storm. Simulation results show that the proposed method can greatly reduce the total number of packets transmitted in the network, and the successful information delivery ratio and information delivery time can also be improved.
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| 3. |
- Li, Yuhong, et al.
(författare)
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Enhancing the internet of things with knowledge-driven software-defined networking technology : Future perspectives
- 2020
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Ingår i: Sensors. - : MDPI AG. - 1424-8220. ; 20:12, s. 1-20
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Tidskriftsartikel (refereegranskat)abstract
- The Internet of Things (IoT) connects smart devices to enable various intelligent services. The deployment of IoT encounters several challenges, such as difficulties in controlling and managing IoT applications and networks, problems in programming existing IoT devices, long service provisioning time, underused resources, as well as complexity, isolation and scalability, among others. One fundamental concern is that current IoT networks lack flexibility and intelligence. A network-wide flexible control and management are missing in IoT networks. In addition, huge numbers of devices and large amounts of data are involved in IoT, but none of them have been tuned for supporting network management and control. In this paper, we argue that Software-defined Networking (SDN) together with the data generated by IoT applications can enhance the control and management of IoT in terms of flexibility and intelligence. We present a review for the evolution of SDN and IoT and analyze the benefits and challenges brought by the integration of SDN and IoT with the help of IoT data. We discuss the perspectives of knowledge-driven SDN for IoT through a new IoT architecture and illustrate how to realize Industry IoT by using the architecture. We also highlight the challenges and future research works toward realizing IoT with the knowledge-driven SDN.
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| 4. |
- Li, Yuhong, et al.
(författare)
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Implicit Cooperative Caching based on Information Popularity for Vehicular Networks
- 2017
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Ingår i: CHANTS 2017. - New York : ACM Digital Library. - 9781450351447 ; , s. 51-56
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Konferensbidrag (refereegranskat)abstract
- Information dissemination is one of the most important tasks of vehicular networks. Therefore, information-centric networking (ICN) technology is being more and more widely used in vehicular networks due to the connectionless and lightweight characteristics of this networking paradigm. Caching plays an essential role in information-centric networks, but current caching techniques for ICN are not ideal for use in vehicular networks on account of the dynamicity and wireless transmission of vehicular networks. This paper presents a caching approach for ICN-based vehicular networks that takes into account both the dynamicity of vehicular networks and the popularity of the information to be distributed. By introducing the “interval” metric and estimating the popularity of information and current networking conditions of the vehicles on road, cooperative caching among nodes can be realized without exchanging cache management information among them. Simulation results show that the proposed approach can increase the storage space utilization and has low data response time for vehicular networks.
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| 5. |
- Zhang, Shuangshuang, et al.
(författare)
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Discovery of carbon-based strongest and hardest amorphous material
- 2022
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Ingår i: National Science Review. - : Oxford University Press. - 2095-5138 .- 2053-714X. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Carbon is one of the most fascinating elements due to its structurally diverse allotropic forms stemming from its bonding varieties (sp, sp2, and sp3). Exploring new forms of carbon has always been the eternal theme of scientific research. Herein, we report the amorphous (AM) carbon materials with high fraction of sp3 bonding recovered from compression of fullerene C60 under high pressure and high temperature previously unexplored. Analysis of photoluminescence and absorption spectra demonstrates that they are semiconducting with a bandgap range of 1.5–2.2 eV, comparable to that of widely used amorphous silicon. Comprehensive mechanical tests demonstrate that the synthesized AM-III carbon is the hardest and strongest amorphous material known so far, which can scratch diamond crystal and approach its strength. The produced AM carbon materials combine outstanding mechanical and electronic properties, and may potentially be used in photovoltaic applications that require ultrahigh strength and wear resistance.
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