| 1. |
- Li, Lianyi, et al.
(författare)
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THz-Over-Fiber System With Orthogonal Chirp Division Multiplexing for Integrated Sensing and Communication
- 2024
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Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; 42:1, s. 176-183
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Tidskriftsartikel (refereegranskat)abstract
- To achieve integrated sensing and communication (ISAC) applications with high data rates and high resolution, the terahertz-over-fiber (ToF) system has been recognized as a promising solution. However, the frequency-selective fading would deteriorate the performance of the ToF-based ISAC systems. In this work, we propose the orthogonal chirp division multiplexing (OCDM) waveform-based ToF system for high-performance ISAC applications. The system encodes data with the phase of the sub-chirps and obtains radar images by processing echoes with the zero-padded matched filtering algorithm. We experimentally demonstrate a proof-of-concept OCDM-ToF system, which simultaneously achieves a 32 Gbit/s data rate and 1.875 cm range resolution after transmission over a 10 km optical fiber and a 3.14 m wireless link at the THz band, for the first time. The experimental results indicate that the OCDM-ToF system can enhance robustness against the frequency-selective fading issue, as a benefit improving communication performance with high data rates while preserving the high sensing resolution of OFDM in the THz ISAC applications.
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| 2. |
- Yu, Xianbin, et al.
(författare)
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Terahertz Photonics in Radar and ISAC Applications
- 2023
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Ingår i: 2023 Asia Communications and Photonics Conference/2023 International Photonics and Optoelectronics Meetings, ACP/POEM 2023. - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- This paper reviews our recent progress on photonic terahertz radar and integrated sensing and communication (ISAC) systems in the 300GHz band with distinguished sensing performance.
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| 3. |
- Zhang, Yinping, et al.
(författare)
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Ten cities cross-sectional questionnaire survey of children asthma and other allergies in China
- 2013
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Ingår i: Chinese Science Bulletin. - : Springer Science and Business Media LLC. - 1001-6538 .- 1861-9541. ; 58:34, s. 4182-4189
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Tidskriftsartikel (refereegranskat)abstract
- Asthma, rhinitis and eczema (allergic or non-allergic) have increased throughout the world during the last decades, especially among children. Changes in the indoor environment are suspected to be important causes. China has experienced a dramatic change in indoor environmental exposures during the past two decades. However, such changes and their associations with children's asthma and other health aspects have not been thoroughly studied. China, Children, Homes, Health (CCHH), Phase I, was a cross-sectional questionnaire survey of 48219 children 1-8 years old in 10 Chinese cities during 2010-2012. The questionnaire includes the International Study of Asthma and Allergies in Childhood (ISAAC) core health questions and additional questions regarding housing, life habits and outdoor environment. In health analyses, children aged 3-6 years old were included. The prevalences of doctor diagnosed asthma varied from 1.7% to 9.8% (mean 6.8%), a large increase from 0.91% in 1999 and 1.50% in 2000. The prevalence of wheeze, rhinitis and atopic eczema (last 12 months) varied from 13.9% to 23.7%, 24.0% to 50.8% and 4.8% to 15.8%, respectively. Taiyuan had the lowest prevalences of all illnesses and Shanghai the highest, except for wheezewhere the highest value was for Urumqi. We found (1) no obvious association between disease prevalences and ambient PM10 concentrations and (2) higher prevalences of disease in humid climates with hot summers and cold winters, but with no centrally heated buildings. Associations between the diseases and economic status as indexed by Gross Domestic Product (GDP) requires further study.
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| 4. |
- Lyu, Zhidong, et al.
(författare)
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Multi-Channel Photonic THz-ISAC System Based on Integrated LFM-QAM Waveform
- 2024
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Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; 42:11, s. 3981-3988
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Tidskriftsartikel (refereegranskat)abstract
- The integrated sensing and communication (ISAC) has been envisioned as a promising technology to simultaneously perform high-capacity communication and high-accuracy sensing with efficient resource utilization. Nevertheless, due to the severe mutual constraints between communication and sensing functions, the performance of previously reported ISAC demonstrations notably trails that of individual communication or sensing systems. In this work, an integrated LFM-QAM waveform is proposed and theoretically analyzed by combining linear frequency modulation (LFM) and quadrature amplitude modulation (QAM) formats. Employing the proposed waveform and optical wavelength division multiplexing (WDM) technique, we experimentally implement a multi-channel photonic terahertz (THz)-ISAC wireless system operating at 275 GHz band, simultaneously achieving a communication data rate up to 120 Gbps and a range resolution as high as 2.5 mm. To the best of our knowledge, this is the first time to demonstrate beyond 100 Gbps wireless data rate and mm-scale resolution based on an integrated waveform in the THz region, revealing the potential of THz-ISAC performance.
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| 5. |
- Lyu, Zhidong, et al.
(författare)
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Preamble-Free Synchronization Based on Dual-chirp Waveforms for Photonic THz-ISAC
- 2024
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Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; 42:8, s. 2657-2665
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Tidskriftsartikel (refereegranskat)abstract
- The integrated sensing and communication (ISAC) systems based on the linear frequency modulation (LFM) waveforms have attracted substantial attention. However, existing routines suffer from additional synchronization preamble overhead, which limits both communication and sensing performance. This work, using the dual-chirp with opposite slopes, exploits a preamble-free synchronization scheme for the LFM-based ISAC. We first theoretically analyze the quasi-orthogonal property of the proposed dual-chirp LFM waveform and derive its achievable communication rate and range ambiguity function. A photonics-assisted proof-of-concept ISAC experiment is conducted in the 300 GHz frequency band, achieving a 20 Gbps data rate with a distinguished peak sidelobe ratio (PSLR) of up to 29.2 dB and 1.5 cm range resolution. More importantly, less than 0.5% synchronous power overhead is needed in our scheme. In addition, the performance trade-off induced by the data rate and amplitude ratio is validated in the experiment, which is in line with our theoretical analysis. Therefore, the proposed scheme provides a promising solution for synchronizing LFM-based future ISAC systems.
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| 6. |
- Lyu, Zhidong, et al.
(författare)
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Radar-Centric Photonic Terahertz Integrated Sensing and Communication System Based on LFM-PSK Waveform
- 2023
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Ingår i: IEEE transactions on microwave theory and techniques. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9480 .- 1557-9670. ; 71:11, s. 5019-
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Tidskriftsartikel (refereegranskat)abstract
- The radar-centric terahertz integrated sensing and communication (THz-ISAC) is identified as a significant application in future wireless access networks. Up to date, previously reported demonstrations regarding radar sensing performance lack sufficient support in a complex environment with a strong target masking effect. This work tacks this problem by proposing a radar-centric waveform combining linear frequency modulation (LFM) waveform and phase shift keying (PSK). We first derive sensing metrics of the LFM-PSK waveform through theoretical analysis, including range resolution, peak sidelobe ratio (PSLR), and Cramér-Rao lower bound (CRLB). Then a proof-of-concept experiment on a photonics-assisted integrated sensing and communication (ISAC) system operating at 330 with 18 GHz bandwidth is conducted to verify the performance of the proposed LFM-PSK waveform. In the experiment, the proposed waveform can reach a PSLR of up to 20.9 dB and a range resolution of 1.3 cm, simultaneously accommodating a data transmission of 6 Gbit/s. In addition, the effect of embedding symbols on sensing metrics is also discussed, and by comparing the range solution and PSLR with various data rates, around $\sim$ 6 dB gain in the PSLR without any deterioration of range resolution is observed.
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| 7. |
- Mo, Lixin, et al.
(författare)
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Nano-Silver Ink of High Conductivity and Low Sintering Temperature for Paper Electronics
- 2019
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Ingår i: Nanoscale Research Letters. - : Springer New York LLC. - 1931-7573 .- 1556-276X. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Highly conductive ink with low sintering temperature is important for printed electronics on paper substrate. Silver nanoparticles (Ag NPs) of different average radii ranging from 48 to 176 nm were synthesized by adjusting the Ag+ concentration in the reaction process. The electric resistivity of the Ag NP-based ink film in relation to Ag NP size, sintering temperature, amount of PVP capping agent on Ag NP surface, and morphology evolution of the film during heating process was investigated. It was found that the resistivity of the films reduced very rapidly with increasing particle size due above all to reduced amount of protective agent capping on the Ag NPs. A semi-empirical relationship between the resistivity and the particle size was proposed. With the help of this mathematical expression, one gains both systematic and detailed insight to the resistivity evaluation with regard to the Ag particle size. The optimal electric resistivity of 4.6 μΩ cm was achieved at 140 °C for 10 min which was very close to the resistivity value of bulk Ag (1.58 μΩ cm). Mechanical flexibility of the printed electronics with the Ag NP-based ink on paper substrates was investigated. The prints on the art coated paper exhibited better flexibility compared to that on the photopaper. This might be attributed to the surface coating composition, surface morphology of the paper, and their corresponding ink absorption property. © 2019, The Author(s).
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| 8. |
- Jablonka, Lukas, et al.
(författare)
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Improving the morphological stability of nickel germanide by tantalum and tungsten additions
- 2018
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 112:10
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Tidskriftsartikel (refereegranskat)abstract
- To enhance the morphological stability of NiGe, a material of interest as a source drain-contact in Ge-based field effect transistors, Ta or W, is added as either an interlayer or a capping layer. The efficacy of this Ta or W addition is evaluated with pure NiGe as a reference. While interlayers increase the NiGe formation temperature, capping layers do not retard the NiGe formation. Regardless of the initial position of Ta or W, the morphological stability of NiGe against agglomeration can be improved by up to 100 degrees C. The improved thermal stability can be ascribed to an inhibited surface diffusion, owing to Ta or W being located on top of NiGe after annealing, as confirmed by means of transmission electron microscopy, Rutherford backscattering spectrometry, and atom probe tomography. The latter also shows a 0.3 at. % solubility of Ta in NiGe at 450 degrees C, while no such incorporation of W is detectable.
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| 9. |
- Li, Shenghui, 1994-, et al.
(författare)
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Blades : A Unified Benchmark Suite for Byzantine Attacks and Defenses in Federated Learning
- 2024
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Ingår i: 9TH ACM/IEEE CONFERENCE ON INTERNET OF THINGS DESIGN AND IMPLEMENTATION, IOTDI 2024. - : IEEE. - 9798350370256 - 9798350370263 ; , s. 158-169
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Konferensbidrag (refereegranskat)abstract
- Federated learning (FL) facilitates distributed training across different IoT and edge devices, safeguarding the privacy of their data. The inherent distributed structure of FL introduces vulnerabilities, especially from adversarial devices aiming to skew local updates to their advantage. Despite the plethora of research focusing on Byzantine-resilient FL, the academic community has yet to establish a comprehensive benchmark suite, pivotal for impartial assessment and comparison of different techniques. This paper presents Blades, a scalable, extensible, and easily configurable benchmark suite that supports researchers and developers in efficiently implementing and validating novel strategies against baseline algorithms in Byzantine-resilient FL. Blades contains built-in implementations of representative attack and defense strategies and offers a user-friendly interface that seamlessly integrates new ideas. Using Blades, we re-evaluate representative attacks and defenses on wide-ranging experimental configurations (approximately 1,500 trials in total). Through our extensive experiments, we gained new insights into FL robustness and highlighted previously overlooked limitations due to the absence of thorough evaluations and comparisons of baselines under various attack settings. We maintain the source code and documents at https://github.com/lishenghui/blades.
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| 10. |
- Li, Shenghui, 1994-, et al.
(författare)
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Demo Abstract : Blades: A Unified Benchmark Suite for Byzantine-Resilient in Federated Learning
- 2024
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Ingår i: 9TH ACM/IEEE CONFERENCE ON INTERNET OF THINGS DESIGN AND IMPLEMENTATION, IOTDI 2024. - : IEEE Computer Society. - 9798350370256 - 9798350370263 ; , s. 229-230
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Konferensbidrag (refereegranskat)abstract
- Federated learning (FL) facilitates distributed training across different IoT and edge devices, safeguarding the privacy of their data. The inherently distributed nature of FL introduces vulnerabilities, especially from adversarial devices aiming to skew local updates to their desire. Despite the plethora of research focusing on Byzantine-resilient FL, the academic conununity has yet to establish a comprehensive benchmark suite, pivotal for the assessment and comparison of different techniques. This demonstration presents Blades, a scalable, extensible, and easily configurable benchmark suite that supports researchers and developers in efficiently implementing and validating strategies against baseline algorithms in Byzantine-resilient FL.
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