| 1. |
- He, Lei, et al.
(författare)
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Non-symmetric responses of leaf onset date to natural warming and cooling in northern ecosystems
- 2023
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Ingår i: PNAS Nexus. - 2752-6542. ; 2:9
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Tidskriftsartikel (refereegranskat)abstract
- The northern hemisphere has experienced regional cooling, especially during the global warming hiatus (1998-2012) due to ocean energy redistribution. However, the lack of studies about the natural cooling effects hampers our understanding of vegetation responses to climate change. Using 15,125 ground phenological time series at 3,620 sites since the 1950s and 31-year satellite greenness observations (1982-2012) covering the warming hiatus period, we show a stronger response of leaf onset date (LOD) to natural cooling than to warming, i.e. the delay of LOD caused by 1°C cooling is larger than the advance of LOD with 1°C warming. This might be because cooling leads to larger chilling accumulation and heating requirements for leaf onset, but this non-symmetric LOD response is partially offset by warming-related drying. Moreover, spring greening magnitude, in terms of satellite-based greenness and productivity, is more sensitive to LOD changes in the warming area than in the cooling. These results highlight the importance of considering non-symmetric responses of spring greening to warming and cooling when predicting vegetation-climate feedbacks.
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| 2. |
- Lei, Wenxin, et al.
(författare)
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Edge-enabled Zero Trust Architecture for ICPS with Spatial and Temporal Granularity
- 2023
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Ingår i: Proceedings - 2023 IEEE 6th International Conference on Industrial Cyber-Physical Systems, ICPS 2023. - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- Motivated by the rapid advancement of industrial cyber-physical systems (ICPS) and rising voices in favor of zero trust (ZT) security, in this paper, we present an edge-enabled zero trust architecture (ZTA) for ICPS. ZT is thought to be relevant to ICPS with the spatial and temporal granularity in the suggested architecture. In addition to continuous authentication and a dynamic access-control mechanism at the temporal granularity, we recommend edge segmentation at the spatial granularity with microservices as the division units. Finally, we conduct a security assessment of the proposed architecture in the presence of threats faced by ICPS. Overall, our analysis shows that the proposed ZTA helps to promote the security of ICPS.
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| 3. |
- Lei, Wenxin, et al.
(författare)
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FDI Attack Detection at the Edge of Smart Grids Based on Classification of Predicted Residuals
- 2022
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Ingår i: IEEE Transactions on Industrial Informatics. - : Institute of Electrical and Electronics Engineers (IEEE). - 1551-3203 .- 1941-0050. ; 18:12, s. 9302-9311
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Tidskriftsartikel (refereegranskat)abstract
- The introduction of information and communication technologies makes network environments increasingly open, leaving smart-grid control systems incredibly vulnerable to malicious attacks. False data injection (FDI) attacks stealthily tamper with measurement data, resulting in erroneous decisions made by the control center that greatly influence the normal operation of the power system. By taking advantage of real-time data acquisition with edge computing, in this article, we propose a scheme based on classification of predicted residuals (CPRs) for the FDI attack detection. The CPR scheme first predicts the acquired measurement data at the edge of the sensing network via developing an accurate prediction model. Followed the novel real-time classification method under the edge devices supporting, it classifies the predicted residuals independent of the false data to enhance the detection accuracy. Through these two steps, the detection rate of FDI attacks is greatly improved. The proposed scheme is validated in a real microgrid testbed. Experimental results show that the CPR scheme performs well in detecting FDI attacks and remains sensitive in injection attack probability and magnitude. The detection scheme even has effectiveness at low injection attack probability and magnitude (5% and 0.018 per thousand, respectively). Furthermore, it also proves that the proposed scheme has applicability in high real-time requirements at the edge of smart grids.
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| 4. |
- Lu, Mengge, et al.
(författare)
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Heterogeneity in vegetation recovery rates post-flash droughts across different ecosystems
- 2024
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Ingår i: Environmental Research Letters. - 1748-9326. ; 19:7
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Tidskriftsartikel (refereegranskat)abstract
- Flash droughts, as sub-seasonal phenomena, are characterized by their rapid onset and significant impact on terrestrial ecosystems. However, understanding how vegetation responds to flash droughts and the mechanisms governing vegetation recovery remains elusive. Here, we analysed the response of vegetation productivity to flash droughts and identified the most relevant drivers controlling vegetation recovery using two soil moisture datasets (ERA5-land and Global Land Data Assimilation System) and two satellite-based vegetation productivity proxies (gross primary productivity, and solar-induced chlorophyll fluorescence). Our results show that South China and Northeast China stand out as hotspots for flash droughts, with higher frequency and speed. Notably, although the frequency of flash droughts in cropland is relatively low, and their speed is very high, with a median of 10.9% per pentad. Most ecosystems can recover to their normal state within 25 d. Vegetation with shallow roots, such as cropland and grassland, responds rapidly to flash droughts. Ecosystems generally exhibit extended response time with increasing plant rooting depth. The recovery rate of vegetation productivity from flash droughts is mainly controlled by vegetation physiology (decline rate of productivity upon exposure to flash drought) and modulated by flash drought characteristics, especially severity for forests and speed for cropland and grassland. This study provides valuable insights into the mechanisms underlying vegetation responses to flash droughts.
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| 5. |
- Xie, Feiyi, et al.
(författare)
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Weighted Voting in Physical Layer Authentication for Industrial Wireless Edge Networks
- 2022
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Ingår i: IEEE Transactions on Industrial Informatics. - : Institute of Electrical and Electronics Engineers (IEEE). - 1551-3203 .- 1941-0050. ; 18:4, s. 2796-2806
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Tidskriftsartikel (refereegranskat)abstract
- Edge computing (EC) is an essential component of large-scale intelligent manufacturing systems for Industry 4.0, which promises to provide a preprocessing platform for the massive data generated by the terminals and guarantee lower delay and more security compared to directly processing data in cloud computing. Nevertheless, access authentication is a crucial security issue of current EC systems, and, thus, this article presents a solution to enhance the access classification accuracy by exploiting the physical layer information. Our method employs a weighted voting scheme for channel state information based authentication using a single sample which includes sample segmentation, grouping, and weighted voting and finally achieves the fast and low complexity secure-access requirement of the EC system without increasing the individual devices' sample size and computational complexity. Experimental results utilizing public datasets and field-measured datasets demonstrate that the proposed weighted voting method has higher accuracy and robustness than existing methods.
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