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Your search keyword '"Zhao, Haoyuan"' showing total 36 results
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36 results on '"Zhao, Haoyuan"'

1. LEO Satellite Network Access in the Wild: Potentials, Experiences, and Challenges

Author

Ma, Sami, Chou, Yi Ching, Zhang, Miao, Fang, Hao, Zhao, Haoyuan, Liu, Jiangchuan, and Atlas, William I.

Subjects
Computer Science - Networking and Internet Architecture, C.2.1
Abstract

In the past three years, working with the Pacific Salmon Foundation and various First Nations groups, we have established Starlink-empowered wild salmon monitoring sites in remote Northern British Columbia, Canada. We report our experiences with the network services in these challenging environments, including deep woods and deep valleys, that lack infrastructural support with some close to Starlink's service boundary at the far north. We assess the portability and mobility of the satellite dishes and the quality of existing network access in underdeveloped countries that Starlink expects to cover. Our experiences suggest that network access based on LEO satellite constellations holds promise but faces hurdles such as energy supply constraints and environmental factors like temperature, precipitation, and solar storms. The presence of wildlife and respecting local residents' culture and heritage pose further complications. We envision several technical solutions addressing the challenges and believe that further regulations will be necessary., Comment: 8 pages, 6 figures

Published
2024
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2. Network Characteristics of LEO Satellite Constellations: A Starlink-Based Measurement from End Users

Author

Ma, Sami, Chou, Yi Ching, Zhao, Haoyuan, Chen, Long, Ma, Xiaoqiang, and Liu, Jiangchuan

Subjects
Computer Science - Networking and Internet Architecture
Abstract

Low Earth orbit Satellite Networks (LSNs) have been advocated as a key infrastructure for truly global coverage in the forthcoming 6G. This paper presents our initial measurement results and observations on the end-to-end network characteristics of Starlink, arguably the largest LSN constellation to date. Our findings confirm that LSNs are a promising solution towards ubiquitous Internet coverage over the Earth; yet, we also find that the users of Starlink experience much more dynamics in throughput and latency than terrestrial network users, and even frequent outages. Its user experiences are heavily affected by environmental factors such as terrain, solar storms, rain, clouds, and temperature, so is the power consumption. We further analyze Starlink's current bent-pipe relay strategy and its limits, particularly for cross-ocean routes. We have also explored its mobility and portability potentials, and extended our experiments from urban cities to wild remote areas that are facing distinct practical and cultural challenges., Comment: 12 pages, 20 figures, to be published in IEEE INFOCOM 2023

Published
2022

20. Reliability Sensitivity Analysis of Stochastic Resonance Failure of Vehicle Drum Brake

Author

Pak Unsong, Zhao Haoyuan, and Yang Zhou

Subjects
Computer science, Modal analysis, Brake, Drum brake, Robust optimization, Workbench, Natural frequency, Sensitivity (control systems), Automotive engineering, Reliability (statistics)
Abstract

Brakes play an important role in the slowing down and stopping of vehicles, forming a critical part of the automotive safety system. The reliability of brakes can significantly impact the safety and reliability of the entire vehicle. In order to study the influence of random parameters (brake structure and material, etc.) on brake frequency reliability, Workbench software was used to conduct modal analysis and harmonic response analysis on a drum brake. A BP neural network was used to establish the first order natural frequency function model of a drum brake. The advanced First-Order Second-Moment method was adopted to obtain the frequency reliability and reliability sensitivity curves of the drum brake, the results were verified by the Monte-Carlo method. The results showed that the drum brake design is reliable and the influence of random parameters on the frequency reliability of the brake was determined, which lays a foundation for the robust optimization design of the drum brake.

Published
2020

26. Manipulation of Chain Entanglement and Crystal Networks of Biodegradable Poly(butylene adipate-co-butylene terephthalate) During Film Blowing through the Addition of a Chain Extender: An In Situ Synchrotron Radiation X-ray Scattering Study

Author

Zhao, Haoyuan, primary, Li, Lifu, additional, Zhang, Qianlei, additional, Xia, Zhijie, additional, Yang, Erjie, additional, Wang, Yusong, additional, Chen, Wei, additional, Meng, Lingpu, additional, Wang, Daoliang, additional, and Li, Liangbin, additional

Published
2019
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32. Heterologous expression of two <italic>Aspergillus niger</italic> feruloyl esterases in <italic>Trichoderma reesei</italic> for the production of ferulic acid from wheat bran.

Author

Long, Liangkun, Zhao, Haoyuan, Ding, Dafan, Xu, Meijuan, and Ding, Shaojun

Abstract

Feruloyl esterase (FAE)-encoding genes AnfaeA and AnfaeB were isolated from Aspergillus niger 0913. For overexpression of the two genes in Trichoderma reesei, constitutive and inductive expression plasmids were constructed based on parental plasmid pAg1-H3. The constructed plasmids contained AnfaeA or AnfaeB gene under the control of glyceraldehyde-3-phosphate dehydrogenase A gene (gpdA) promoter (from A. nidulans) or cellobiohydrolases I (cbh I) gene promoter (from T. reesei), and cbh I terminator from T. reesei. The target plasmids were transferred into T. reesei D-86271 (Rut-C30) by Agrobacterium tumefaciens-mediated transformation (ATMT), respectively. A high level of feruloyl esterase was produced by the recombinant fungal strains under solid-state fermentation, and the cbh I promoter was more efficient than the gpdA promoter in the expression of AnfaeA. The optimum temperatures and pH values were 50 °C and 5.0 for AnFAEA, and 35 °C and 6.0 for AnFAEB. The maximum production levels were 20.69 U/gsd for AnFAEA and 15.08 U/gsd for AnFAEB. The recombinant fungal enzyme systems could release 62.9% (for AnFAEA) and 52.2% (for AnFAEB) of total ferulic acids from de-starched wheat bran, which was higher than the 46.3% releasing efficiency of A. niger 0913. The supplement of xylanase from T. longibrachiatum in the enzymatic hydrolysis led to a small increment of the ferulic acids release. [ABSTRACT FROM AUTHOR]

Published
2018
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36. Chain dynamics and crystalline network structure of poly[ R -3-hydroxybutyrate- co -4-hydroxybutyrate] as revealed by solid-state NMR.

Author

Xia Z, Zhao H, Wang Y, Ma Y, Wang X, Meng L, Wang D, Sheng J, and Chen W

Abstract

The chain dynamics and crystalline network structure of poly[R-3-hydroxybutyrate-co-4-hydroxybutyrate] (P(3HB-co-4HB)) were systematically investigated by the combination of various solid-state NMR techniques. High-resolution 13C cross-polarization (CP) and direct-polarization (DP) MAS with selective recycle delay times were first used to check the presence or absence of the 4HB unit in the crystalline domain. The results show that the 4HB unit is excluded from the crystalline domain. Afterward, 1H MAS Nuclear Overhauser Effect Spectroscopy (NOESY) with different mixing times was used, which shows that no micro-phase separation exists in the amorphous domain. 1H magic-sandwich-echo (MSE)-FID at elevated temperature shows the absence of motions on a timescale of 100 μs and below in the crystalline domain, as evidenced by the invariant second moment M2 of the proton line shape. Finally, the crystalline based network density was characterized directly by magic and polarization echo (MAPE)-double quantum (DQ) NMR, which shows a significant decreasing tendency after 80 °C. Such a decreasing crystalline network density, together with the reduced relaxation time, results in the significant decrement of the maximum stretch ratio and modulus in the high-temperature region.

Published
2021
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