| 1. |
- Xin, Zhiging, et al.
(författare)
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Scalable Fabrication of Conductive Lines by Patterned Wettability-Assisted Bar-Coating for Low Cost Paper-Based Circuits
- 2019
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Ingår i: Advanced Materials Interfaces. - : Wiley-VCH Verlag. - 2196-7350. ; 6:10
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Tidskriftsartikel (refereegranskat)abstract
- Patterning technology on the paper based on wettability difference for paper-based devices has attracted significant attention for its low cost, easy degradability, and high flexibility. Here, conductive lines are rapidly prepared by patterned wettability-assisted bar-coating for low cost paper-based circuits. It is found that 7 s plasma treatment time for acquiring wettability difference is optimal, which resulted in not only effective splitting of the liquid film but also highly consistent line width with mask. Moreover, low retention force of hydrophobic surface is imperative for self-confinement of the ink into hydrophilic areas, especially for ink with high solid content. The sheet resistance of patterns can reach 5 Ω ◻ −1 after 980 nm laser sintering when using 50 wt% solid content ink with 110 cP viscosity. The geometries of line patterns, i.e., line width and spacing, can be readily tuned by varying the designed size of mask patterns. As-prepared conductive patterns show good conductivity even after 500 bending cycles at 2 mm bending radius. It is believed that this study will provide deeper understanding of wettability difference-assisted patterning process and represents a general strategy for selective wetting, especially for high viscosity ink.
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| 2. |
- 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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| 3. |
- Mo, Lixin, et al.
(författare)
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On the temperature dependency and reversibility of sheet resistance of silver nanoparticles covered by 3-mercaptopropionic acid
- 2017
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Ingår i: Journal of materials science. Materials in electronics. - : Springer Science and Business Media LLC. - 0957-4522 .- 1573-482X. ; 28:5, s. 4035-4043
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Tidskriftsartikel (refereegranskat)abstract
- The temperature dependency and reversibility of the sheet resistance of silver nanoparticles covered by 3-mercaptopropionic acid (Ag-MPA) molecules, used in the printed temperature sensor, has been investigated. The microstructural evaluation, the FTIR spectra and thermal property analyses of the Ag-MPA films suggest co-existence of both weakly adsorbed as well as firmly adsorbed MPA molecules on the surface of Ag nanoparticles. The weakly adsorbed MPA molecules was to a great extent be desorbed and removed from the surfaces of silver nanoparticles when heated up to 180 °C for the first time. While the firmly adsorbed MPA molecules remain on the surfaces of silver nanoparticles even at higher temperature. Yet the firmly adsorbed MPA molecules are likely having gone through a transformation circle from/to the gauche and trans conformations in correspondence to a heating and cooling cycle, which results in temperature dependent and reversible sheet resistance. The MPA molecules in the gauche conformation are more densely packed on the surface of silver nanoparticles and can hinder the electron’s movability within the Ag-MPA film. While in the trans conformation with lower ‘surface space’ coverage by the MPA molecules, electrons move more freely within the film. Based on the temperature dependent nature, the fully printed temperature sensor using the Ag-MPA nanoparticles as the functional layer was made, of which the highest sensitivity is 5.12% °C−1 at 200 °C.
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| 4. |
- He, Yuan, et al.
(författare)
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Acoustic Localization System for Precise Drone Landing
- 2024
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Ingår i: IEEE Transactions on Mobile Computing. ; 23:5, s. 4126-4144
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Tidskriftsartikel (refereegranskat)abstract
- We present MicNest: an acoustic localization system enabling precise drone landing. In MicNest, multiple microphones are deployed on a landing platform in carefully devised configurations. The drone carries a speaker transmitting purposefully-designed acoustic pulses. The drone may be localized as long as the pulses are correctly detected. Doing so is challenging: i) because of limited transmission power, propagation attenuation, background noise, and propeller interference, the Signal-to-Noise Ratio (SNR) of received pulses is intrinsically low; ii) the pulses experience non-linear Doppler distortion due to the physical drone dynamics; iii) as location information is used during landing, the processing latency must be reduced to effectively feed the flight control loop. To tackle these issues, we design a novel pulse detector, Matched Filter Tree (MFT), whose idea is to convert pulse detection to a tree search problem. We further present three practical methods to accelerate tree search jointly. Our experiments show that MicNest can localize a drone 120 m away with 0.53% relative localization error at 20 Hz location update frequency. For navigating drone landing, MicNest can achieve a success rate of 94 %. The average landing error (distance between landing point and target point) is only 4.3 cm.
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| 5. |
- 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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| 6. |
- 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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| 7. |
- 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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| 8. |
- Li, Xin, et al.
(författare)
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Research on the permeability of ink in offset paper
- 2014
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Ingår i: Applied Mechanics and Materials. - 1660-9336 .- 1662-7482. ; 469, s. 313-317
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Tidskriftsartikel (refereegranskat)abstract
- First, the study chooses ten kinds of offset paper. By using a dynamic penetration analyzer (HVL-PDA) and water as test fluid, the dynamic absorption characteristics of the ten kinds of offset paper are measured. At the same time, proofs of offset printing patterns of these ten kinds of offset paper are made by using a printability tester. Then the depths of ink penetration in ten kinds of offset paper are measured by the Three-dimensional video microscopy system and the study analyzes the effect of paper dynamic absorption property on penetration depth of ink. The results of the analyses show that the penetration depth of ink is closely related to dynamic liquid absorption, thus the permeability of ink in offset paper can be predicted from the dynamic liquid absorption of offset paper.
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| 9. |
- Li, Yaoxing, et al.
(författare)
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A named data approach for DTN routing
- 2017
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Ingår i: 2017 Wireless Days, WD 2017. - Piscataway, NJ : Institute of Electrical and Electronics Engineers (IEEE). - 9781509058563 ; , s. 163-166
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Konferensbidrag (refereegranskat)abstract
- Many common DTN routing protocols are replication-based, which have relatively good performance in terms of message delivery ratio but high overhead, and leave the issue of garbage collection open. In this paper, we propose Named Data Distance Routing (NDDR), a named data based DTN routing approach which makes routing decisions for named data based on topological distance information. This helps to reduce the overhead of routing. We have implemented NDDR in the ONE simulation environment and the simulation results show that the proposed routing method has better performance in terms of message delivery ratio and network overhead compared with several typical replication-based DTN routing protocols.
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| 10. |
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