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Distortion minimization for multimedia transmission in NOMA HAP-UAV integrated aerial access networks

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Chinese Journal of Aeronautics 2022年第9期35卷 81-94页

作者： guobin zhang Zhu HAN Hang XIN Xin WEI Boya DI School of Electrical Engineering and Intelligentization Dongguan University of TechnologyDongguan 523808China Department of Electrical and Computer Engineering and Department of Computer Science University of HoustonTX77004USA School of Computer Science and Technology Dongguan University of TechnologyDongguan 523808China Department of Computing Imperial CollegeLondon SW72AzUK

Aerial access networks have been envisioned as a promising 6G solution to enhance the ground communication systems in both coverage and capacity. To better utilize the spectrum and fully explore different channel characteristics, this paper constructs an integrated network comprising the High Altitude Platform(HAP) and Unmanned Air Vehicles(UAVs) with the NonOrthogonal Multiple Access(NOMA) technology. In order to improve the transmission quality of images and videos, a power management scheme is proposed to minimize the distortion of the transmissions from the HAP and UAVs to the terminals. The power control is formulated as a non-convex problem constrained by the maximal transmit power and the minimal terminal rate requirements. The variable substitution and the first-order Tailor’s expansion is used to transform it into a sequence of convex problems, which are subsequently solved through the gradient projection method. Simulation demonstrates the signal distortion and error rate improvement achieved by the proposed algorithm.

关键词： Aerial Access Networks High Altitude Platform Non-Orthogonal Multiple Access Sixth-Generation Unmanned Air Vehicles

Matrix-assisted pulsed laser evaporation of polyimide thin films and the XPS study

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Science China Chemistry 2008年第10期51卷 983-989页

作者： WANG Wei LI ChengXiang zhang guobin SHENG LiuSi National Synchrotron Radiation Laboratory University of Science and Technology of ChinaHefei 230029China School of Chemistry and Chemical Engineering Shihezi UniversityShihezi 832003China

Compared with the traditional thin film techniques, the matrix-assisted pulsed laser evaporation (MAPLE) technique has many advantages in the deposition of polymer and organic thin films. It has a wide range of applications in many fields, such as non-linear optics, luminescent devices, electronics, various sensors. We have successfully deposited polyimide thin films by using the MAPLE technique. These films were characterized with XPS. The XPS spectra showed that the single-photon effect is ob-vious at low laser fluence and the chemical bonds will be broken, resulting in decomposition of the films. Contrarily, the single-photon effect will decrease and the multi-photon effect and the photothermal effect will increase at high laser fluence, resulting in the protection of the structure of the polyimide thin films and the obvious decrease in decomposition. High laser fluence is more suitable for the deposition of polymer and organic thin films than low laser fluence.

关键词： MAPLE polyimide thin films XPS single-photon effect multi-photon effect

Resource Allocation for Space-Air-Ground Integrated Networks:A Comprehensive Review

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Journal of Communications and Information Networks 2024年第1期9卷 1-23页

作者： Hui Liang Zhiqing Yang guobin zhang Hanxu Hou School of Electrical Engineering and Intelligentization Dongguan University of TechnologyDongguan 523808China Peng Cheng Laboratory Shenzhen 518055China School of Electronics and Information Engineering Shenzhen UniversityShenzhen 518061China School of Electrical Engineering and Intelligentization Dongguan University of TechonologyDongguan 523808China School of Information and Communication Engineering Guangzhou Maritime UniversityGuangzhou 510725China

The space-air-ground integrated networks (SAGIN) has emerged as a critical paradigm to address the growing demands for global connectivity and enhanced communication services. This paper gives a thorough review of the strategies and methodologies for resource allocation within SAGIN, focusing on the challenges and solutions within its complex structure. With the advent of technologies such as 6G, the dynamics of resource optimization have become increasingly complex, necessitating innovative approaches for efficient management. We examine the application of mathematical optimization, game theory, artificial intelligence (AI), and dynamic optimization techniques in SAGIN,offering insights into their effectiveness in ensuring optimal resource distribution, minimizing delays, and maximizing network throughput and stability. The survey highlights the significant advances in AI-based methods,particularly deep learning and reinforcement learning, in tackling the inherent challenges of SAGIN resource allocation. Through a critical review of existing literature, this paper categorizes various resource allocation strategies, identifies current research gaps, and discusses potential future directions. Our findings highlight the crucial role of integrated and intelligent resource allocation mechanisms in realizing the full potential of SAGIN for next-generation communication networks.

关键词： space-air-ground integrated networks resource allocation 6G optimization theory game theory artificial intelligence

GSPAC water movement in extremely dry area

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Journal of Arid Land 2011年第2期3卷 141-149页

作者： HongShou Ll WanFu WANG guobin zhang ZhengMo zhang XiaoWei WANG The Conservation Institute of Dunhuang Academy Dunhuang 736200 China Key Scientific Research Base of Conservation for Ancient Mural State Administration for Cultural Heritage Dunhuang 736200China

Under an extremely arid condition,a PVC greenhouse was built on the top of Mogao Grottoes in gobi *** results of 235-day constant extraction of condensed water on the greenhouse film and soil water content showed that 2.1 g/（m2·d） groundwater moved up and exported into the soil,and a phreatic water evaporation existed in the extreme dry area where the groundwater is buried deeper than 200 *** a prolonged export,the soil water content in the greenhouse was not lower but obviously higher than the original control *** to the monitored parameters including relative humidity and absolute humidity of soil,and temperature outside and inside the greenhouse,it was found that there is the available condition and mechanism for the upward movement of groundwater,and also it can be sure that the exported water was not from the soil and atmosphere outside the *** water,an important source for soil water,interacts with atmosphere moisture via soil *** salinity also has important effects on soil water movement and spatial-temporal *** extremely dry climate,terrestrial heat and change of upper soil temperature are the fundamental driving forces of water transportation and phreatic water evaporation in the Groundwater-Soil-Plant-Atmosphere Continuum（GSPAC） system.

关键词： greenhouse method GSPAC system extremely dry area water movement

First observations of low latitude whistlers using WHU ELF/VLF receiver system

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Science China(Technological Sciences) 2017年第1期60卷 166-174页

作者： CHEN YanPing NI BinBin GU XuDong ZHAO ZhengYu YANG guobin ZHOU Chen zhang YuanNong Department of Space Physics School of Electronic Information Wuhan University Wuhan 430072 China

The recently developed high-quality WHU ELF/VLF receiver system has been deployed in Suizhou, China （geomagnetic lati- tude 21.81°N, longitude 174.44°E, L=1.16） to detect low latitude extremely-low-frequency （ELF： 0.3-3 kHz） and very-low-frequency （VLF： 3-30 kHz） emissions originating from either natural or artificial sources since February 2016. Dur- ing the first-month operation of the receiver system, a total of 3039 clear whistlers have been recorded at this low latitude sta- tion with the majority （97.0%） occurring on 28 February and 1 March 2016. Observed whistlers manifest various types includ- ing single one-hop, echo train, multi-flash, and multi-path. They tend to intensify after local midnight, reach the peak around 04435 LT, and then weaken quickly. Both features of lower cutoff frequencies of most whistlers below -1.6 kHz and almost uniform dispersion for many successive multi-flash whistlers suggest that these whistlers propagate along the geomagnetic field lines in the duct mode. The computed dispersion varies between -15 s1/2 and 23 s1/2 for observed one-hop whistlers and is greater than 50 sm for three-hop echo train whistlers, indicating that the whistlers observed at the Suizhou station are low lati- tude whistlers.

关键词： WHU ELF/VLF receiver whistlers dispersion duct mode

Illumining phase transformation dynamics of vanadium oxide cathode by multimodal techniques under operando conditions

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Nano Research 2019年第4期12卷 905-910页

作者： guobin zhang Tengfei Xiong Xuelei Pan Yunlong Zhao Mengyu Yan Haining zhang Buke Wu Kangning Zhao Liqiang Mai State Key Laboratory of Advanced Technology for Materials Synthesis and Processing International School of Materials Science and Engineering Wuhan University of Technology Wuhan 430070 China Advanced Technology Institute University cfSurrey Guildford GU2 7XH UK National Physical Laboratory Teddington TW11 0LW UK Materials Science and Engineering Department University of Washington Seattle WA 98195-2120 USA

Subtle structural changes during electrochemical processes often relate to the degradation of electrode *** the minute-variations in complementary aspects such as crystal structure,chemical bonds,and electron/ion conductivity will give an in-depth understanding on the reaction mechanism of electrode materials,as well as revealing pathways for ***,vanadium pentoxide (V2O5),a typical cathode material suffering from severe capacity decay during cycling,is characterized by in-situ X-ray diffraction (XRD) and in-situ Raman spectroscopy combined with electrochemical *** phase transitions of V2O5 within the 0-1 LiN ratio are characterized in *** V--O and V-V distances became more extended and shrank compared to the original ones after charge/discharge process,*** with electrochemical tests,these variations are vital to the crystal structure cracking,which is linked with capacity *** work demonstrates that chemical bond changes between the transition metal and oxygen upon cycling serve as the origin of the capacity fading.

关键词： in-situ X-ray diffraction (XRD) in-situ Raman electrochemical process phase transformation

Multi-physics-resolved digital twin of proton exchange membrane fuel cells with a data-driven surrogate model

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Energy and AI 2020年第1期1卷 22-34页

作者： Bowen Wang guobin zhang Huizhi Wang Jin Xuan Kui Jiao State Key Laboratory of Engines Tianjin University135 Yaguan RoadTianjin 300350China Department of Chemical Engineering Loughborough UniversityLoughboroughUK Department of Mechanical Engineering Imperial College LondonLondonUK

The development of multi-physics-resolved digital twins of proton exchange membrane fuel cells(PEMFCs)is sig-nificant for the advancement of this ***,to solve this scientific issue,a surrogate modelling method that combines a state-of-the-art three-dimensional PEMFC physical model and data-driven model is *** surrogate modelling prediction results demonstrate that the test-set relative root mean square errors(rRMSEs)of the multi-physics fields range from 3.88%to 24.80%and can mirror the multi-physics field distribution charac-teristics *** summary,for multi-physics field prediction,the data-driven surrogate model has a comparable accuracy to the comprehensive 3D physical model;however,it considerably reduces the cost of computation and time and achieves the efficient multi-physics-resolved *** model-based designs based on the as-developed digital twin framework,*** PEMFC healthy operation envelope and the PEMFC state map,are *** study highlights the potential of combining data-driven approaches and comprehensive physical models to develop the digital twin of complex systems,such as PEMFCs.

关键词： Proton exchange membrane fuel cell Digital twin Data-driven surrogate model Three-dimensional physical model Model-based design

Water in the Mogao Grottoes,China:where it comes from and how it is driven

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Journal of Arid Land 2015年第1期7卷 37-45页

作者： HongShou LI WanFu WANG HongTao ZHAN Fei QIU QingLin GUO guobin zhang The Conservation Institute of Dunhuang Academy State Administration for Cultural Heritage Key Scientific Research Base of Conservation for Ancient Murals Dunhuang Academy State Administration for Cultural Heritage

The Dunhuang Mogao Grottoes in China was designated as a world heritage site by UNESCO in 1987 and is famous for its cultural relics. Water is the most active factor that harms the relics in the caves as it damages the grotto murals and painted sculptures. Thus, determining the water sources and driving forces of water movement is a key issue for protecting these cultural relics. These issues have troubled relics protectors for a long time. In this study, the authors chose a representative cave in the Mogao Grottoes and, by completely sealing the cave to make a closed system, measured the water vapor from the surrounding rock. This was accomplished by installing a condensation-dehumidification temperature-humidity control system for the collection of water vapor. The results show that there is continuous evaporation from the deep surrounding rock into the cave. The daily evaporation capacity is determined to be 1.02 g/（d·m2）. The water sources and driving forces of water movement were further analyzed according to the character of the water evaporation and by monitoring the temperature and humidity of the surrounding rock. It was found that the water vapor in the cave derives from phreatic water. Moreover, the yearly fluctuation of temperature in the surrounding rock and geothermal forces are the basic powers responsible for driving phreatic evaporation. Under the action of the yearly temperature fluctuations, decomposition and combination of bound water acts as a ＂pump＂ that drives phreatic water migration and evaporation. When the temperature rises, bound water decomposes and evaporates; and when it falls, the rock absorbs moisture. This causes the phreatic water to move from deep regions to shallow ones. Determining the source and dynamic foundation of the water provides a firm scientific basis for protecting the valuable cultural relics in the caves.

关键词： the Silk Road cultural heritage surrounding rock bound and phreatic water thermodynamics

Charge density wave phase suppression in 1T-TiSe_(2) through Sn intercalation

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Nano Research 2022年第3期15卷 2643-2649页

作者： Mukhtar Lawan Adam Hongen Zhu Zhanfeng Liu Shengtao Cui Pengjun zhang Yi Liu guobin zhang Xiaojun Wu Zhe Sun Li Song National Synchrotron Radiation Laboratory CAS Center for Excellence in NanoscienceUniversity of Science and Technology of ChinaHefei230029China Hefei National Laboratory for Physical Sciences at the Microscale CAS Key Laboratory of Materials for Energy ConversionSynergetic Innovation of Quantum Information&Quantum TechnologySchool of Chemistry and Materials Sciencesand CAS Center for Excellence in NanoscienceUniversity of Science and Technology of ChinaHefei 230026China CAS key Laboratory of Strongly-coupled Quantum Matter Physics University of Science and Technology of ChinaHefei 230026China CAS Center for Excellence in Superconducting Electronics(CENSE) Shanghai 200050China Physics Department Bayero UniversityKano 700231Nigeria

Taking advantage of the unique layered structure of TiSe2,the intrinsic electronic properties of two-dimensional materials can easily be tuned via heteroatomic ***,we show that the charge density wave(CDW)phase in 1T-TiSe_(2) single-crystals can be gradually suppressed through Sn atoms *** angle-resolved photoemission spectroscopy(ARPES)and temperature-dependent resistivity measurements,this work reveals that Sn atoms can induce charge doping and modulate the intrinsic electronic properties in the host 1T-TiSe_(2).Notably,our temperature-dependent ARPES results highlight the role exciton-phonon interaction and the Jahn-Teller mechanism through the formation of backfolded bands and exhibition of a downward Se shift of 4p valence band in the formation of CDW in this material.

关键词： charge density wave angle-resolved photoemission spectroscopy(ARPES) charge doping intercalation first-principles single-crystals