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791 results on '"Ge, Jianhua"'

4. Improving Physical Layer Security for Reconfigurable Intelligent Surface aided NOMA 6G Networks

Author

Zhang, Zhe, Zhang, Chensi, Jiang, Chengjun, Jia, Fan, Ge, Jianhua, and Gong, Fengkui

Subjects
Computer Science - Information Theory, Electrical Engineering and Systems Science - Signal Processing
Abstract

The intrinsic integration of the nonorthogonal multiple access (NOMA) and reconfigurable intelligent surface (RIS) techniques is envisioned to be a promising approach to significantly improve both the spectrum efficiency and energy efficiency for future wireless communication networks. In this paper, the physical layer security (PLS) for a RIS-aided NOMA 6G networks is investigated, in which a RIS is deployed to assist the two "dead zone" NOMA users and both internal and external eavesdropping are considered. For the scenario with only internal eavesdropping, we consider the worst case that the near-end user is untrusted and may try to intercept the information of far-end user. A joint beamforming and power allocation sub-optimal scheme is proposed to improve the system PLS. Then we extend our work to a scenario with both internal and external eavesdropping. Two sub-scenarios are considered in this scenario: one is the sub-scenario without channel state information (CSI) of eavesdroppers, and another is the sub-scenario where the eavesdroppers' CSI are available. For the both sub-scenarios, a noise beamforming scheme is introduced to be against the external eavesdroppers. An optimal power allocation scheme is proposed to further improve the system physical security for the second sub-scenario. Simulation results show the superior performance of the proposed schemes. Moreover, it has also been shown that increasing the number of reflecting elements can bring more gain in secrecy performance than that of the transmit antennas.

Published
2021
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7. Cooperative Rate-Splitting for MISO Broadcast Channel with User Relaying, and Performance Benefits over Cooperative NOMA

Author

Zhang, Jian, Clerckx, Bruno, Ge, Jianhua, and Mao, Yijie

Subjects
Computer Science - Information Theory
Abstract

Due to its promising performance in a wide range of practical scenarios, Rate-Splitting (RS) has recently received significant attention in academia for the downlink of communication systems. In this letter, we propose and analyse a Cooperative Rate-Splitting (CRS) strategy based on the three-node relay channel where the transmitter is equipped with multiple antennas. By splitting user messages and linearly precoding common and private streams at the transmitter, and opportunistically asking the relaying user to forward its decoded common message, CRS can efficiently cope with a wide range of propagation conditions (disparity of user channel strengths and directions) and compensate for the performance degradation due to deep fading. The precoder design and the resource allocation are optimized by solving the Weighted Sum Rate (WSR) maximization problem. Numerical results demonstrate that our proposed CRS scheme can achieve an explicit rate region improvement compared to its non-cooperative counterpart and other cooperative strategies (such as cooperative NOMA).

Published
2019
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31. Inter-provincial embodied carbon emission space and industrial transfer paths in China.

Author

Zhang, Wenying, Yang, Mengqi, Ge, Jianhua, and Wang, Gangzhen

Subjects
EMISSIONS (Air pollution), CARBON emissions, SUSTAINABLE development, INDUSTRIAL clusters, ENERGY industries, CARBON offsetting
Abstract

To bolster the dual-circulation development model and green economy, this study delves into the spatiotemporal dynamics of implied carbon transfer in China's inter-provincial and inter-industrial trade, emphasizing its significance for the "dual carbon" objectives. Utilizing multi-regional input-output data from 2012, 2015, and 2017, we employed the multi-region input-output model to gauge embodied carbon transfers across 31 provinces and 28 industries. The Structural Decomposition Analysis (SDA) model further decomposed the growth of trade-related carbon emissions. Key findings include: (1) The electricity and thermal power sectors dominate carbon transfers, with secondary industries seeing rapid growth; (2) Northern provinces significantly outweigh southern ones in carbon transfers and the main direction of it is towards affluent southern coastal regions; (3) Scale effect plays a pivotal role in these transfers. Conclusively, it is crucial for regulatory authorities to rationally formulate region-specific emission policies for inter-regional coordination, and future studies can focus on industrial and spatial clustering effects. [ABSTRACT FROM AUTHOR]

Published
2024
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32. S-scheme heterojunction based on CuWO4/WO3 microspheres with an improved photocatalytic property under visible light irradiation.

Author

Sun, Yangang, Ge, Jianhua, Xu, Jiaqi, and Wang, Jinguo

Subjects
*VISIBLE spectra, *MICROSPHERES, *METHYLENE blue, *ENVIRONMENTAL research, *SOLAR cells, *HETEROJUNCTIONS, *ELECTROCHEMICAL analysis
Abstract

Dye wastewater green treatment has always been one of the research hotspots in the environmental protection and remediation field. The photocatalytic degradation and mineralization of organic dyes are considered to be an energy conservation and effective wastewater remediation technology. Novel CuWO4/WO3 S-scheme nano-heterojunction microspheres were prepared through a convenient hydrothermal route and impregnation–calcination method. The structure, composition, electrochemistry and optical properties of the nano-heterojunction microspheres were systematically evaluated via XRD, SEM, TEM, electrochemical analysis and spectrometry, and the photocatalytic activity of CuWO4/WO3 was investigated using methylene blue (MB) as the probe under visible light irradiation. The CuWO4/WO3 S-scheme nano-heterojunction exhibited a boosted photocatalytic activity compared with WO3 owing to a decrease in carrier transfer resistance and an increase in carrier separation efficiency. The MB degradation rate of the CuWO4/WO3-10 S-scheme nano-heterojunction microspheres is 1.83 and 3.10 times higher than that of pure WO3·2H2O and WO3 microspheres, respectively. Based on the active species capture experiments and the Mott–Schottky curve, an S-scheme mechanism of the photogenerated carrier transfer was elucidated. This study reveals a design and method for the synthesis of S-scheme nano-heterojunction catalysts for application in the wastewater purification field. [ABSTRACT FROM AUTHOR]

Published
2024
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33. Parent Firm Network Dynamics and Foreign Subsidiary Divestment.

Author

Ge, Jianhua, Lu, Jane, and Wu, Xiangting

Abstract

Why divest foreign operations and which subsidiary to close? This study seeks to advance our understanding of foreign divestment by offering a novel explanation from a dynamic network perspective. We posit that subsidiary exit can bring potential network changes to parent firms, the parent firms thus need to weigh the possible network losses in determining whether and which subsidiary to close. This argument gains robust support from our analysis of Japanese firms' foreign investment data between 1994 and 2019. We find that the greater the expected losses in a parent firm's network position (i.e., centrality, status, and brokerage opportunities) resulting from the exit of a foreign subsidiary, the less likely the subsidiary will be closed. Moreover, while the parent firms have strong motives to close the poor-performing subsidiaries, we find that they do adjudicate between performance and network such that those subsidiaries are poor in performance but important in the network may not be closed. We further reveal that such network impacts in a parent firm's foreign divestment decisions are contingent on its international orientation and geographic proximity with its neighboring firms. These findings shed new light on foreign divestment and contribute to the literature on network changes and corporate behaviors. [ABSTRACT FROM AUTHOR]

Published
2024
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45. Adversarial Attack and Defense on Deep Learning for Air Transportation Communication Jamming

Author

Liu, Mingqian, Zhang, Zhenju, Chen, Yunfei, Ge, Jianhua, and Zhao, Nan

Abstract

Air transportation communication jamming recognition model based on deep learning (DL) can quickly and accurately identify and classify communication jamming, to improve the safety and reliability of air traffic. However, due to the vulnerability of deep learning, the jamming recognition model can be easily attacked by the attacker’s carefully designed adversarial examples. Although some defense methods have been proposed, they have strong pertinence to attacks. Thus, new attack methods are needed to improve the defense performance of the model. In this work, we improve the existing attack methods and propose a double level attack method. By constructing the dynamic iterative step size and analyzing the class characteristics of the signals, this method can use the adversarial losses of feature layer and decision layer to generate adversarial examples with stronger attack performance. In order to improve the robustness of the recognition model, we use adversarial examples to train the model, and transfer the knowledge learned from the model to the jamming recognition models in other wireless communication environments by transfer learning. Simulation results show that the proposed attack and defense methods have good performance.

Published
2024
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