检索结果-南通市图书馆

SNR-adaptive deep joint source-channel coding scheme for image semantic transmission with convolutional block attention module

在线全文

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2024年第1期31卷 1-11页

作者： Yang Yujia liu yiming Zhang Wenjia Zhang Zhi State Key Laboratory of Networking and Switch Technology Beijing University of Posts and TelecommunicationsBeijing 100876China

With the development of deep learning(DL),joint source-channel coding(JSCC)solutions for end-to-end transmission have gained a lot of *** deep JSCC schemes support dynamically adjusting the rate according to different channel conditions during transmission,enhancing robustness in dynamic wireless ***,most of the existing adaptive JSCC schemes only consider different channel conditions,ignoring the different feature importance in the image processing and *** uniform compression of different features in the image may result in the compromise of critical image details,particularly in low signal-to-noise ratio(SNR)*** address the above issues,in this paper,a dual attention mechanism is introduced and an SNR-adaptive deep JSCC mechanism with a convolutional block attention module(CBAM)is proposed,in which matrix operations are applied to features in spatial and channel dimensions *** proposed solution concatenates the pooling feature with the SNR level and passes it sequentially through the channel attention network and spatial attention network to obtain the importance evaluation *** show that the proposed solution outperforms other baseline schemes in terms of peak SNR(PSNR)and structural similarity(SSIM),particularly in low SNR scenarios or when dealing with complex image content.

关键词： semantic communication joint source-channel coding image transmission

Crust and Upper Mantle Density Structures beneath the Eastern Tianshan Region and Its Tectonic Implications

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science 2024年第3期35卷 828-838页

作者： yiming liu Chao Chen Qing Liang Zhengwang Hu Hubei Subsurface Multi-Scale Imaging Key Laboratory School of Geophysics and GeomaticsChina University of GeosciencesWuhan 430074China

The deformation mechanisms of the Tianshan orogenic belt(TOB)are one of the most important unresolved issues in the collision of the Indian and Eurasian *** better understand the lithospheric deformation of the eastern Tianshan orogenic belt,we combined the S-wave tomography and gravity data to develop a three-dimensional(3D)density model of the crust and upper mantle beneath the eastern Tianshan *** show that the crust of the eastern Tianshan is mainly characterized by positive density anomalies,revealing widespread subduction-related magmatism during the *** however have also observed extensive low-density anomalies beneath the eastern Tianshan at depths deeper than~100 km,which is likely linked to a relatively hot *** most fundamental differences of the lithosphere within the eastern Tianshan occur in the uppermost *** uppermost mantle layers in the Bogda Shan and Harlik Shan are relatively *** is likely associated with an eclogite body in the uppermost *** most significant negative anomaly of the uppermost mantle is however found in the Jueluotage tectonic belt and the central Tianshan Block and is possibly associated with depleted mantle *** suggest that these differences related to compositional changes may control the strength of the lithospheric mantle and have affected the uplift of the northern and southern segments of the eastern Tianshan after the Permian.

关键词： constrained inversion gravity anomaly three-dimensional lithospheric density structure eastern Tianshan geodynamics geophysics.

Fast spreading of surface ozone in both temporal and spatial scale in Pearl River Delta

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第3期137卷 540-552页

作者： Tianhui Cao Haichao Wang Lei Li Xiao Lu yiming liu Shaojia Fan School of Atmospheric Sciences Sun Yat-sen University and Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519082China Guangdong Provincial Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary Key Laboratory of Tropical Atmosphere-Ocean SystemMinistry of EducationZhuhai 519082China

Surface ozone(O_(3))is a major air pollutant and draw increasing attention in the Pearl River Delta(PRD),***,we characterize the spatial-temporal variability of ozone based on a dataset obtained from 57 national monitoring sites during *** results show that:(1)the seasonal difference of ozone distribution in the inland and coastal areas was significant,which was largely affected by the wind pattern reversals related to the East Asian monsoon,and local ozone production and destruction;(2)the daily maximum 8hr average(MDA8 O_(3))showed an overall upward trend by 1.11 ppbv/*** the trends in the nine cities varied differently by ranging from-0.12 to 2.51 ppbv/*** hot spots of ozone were spreading to southwestern areas from the central areas since *** ozone is becoming a year-round air pollution problem with the pollution season extending to winter and spring in PRD region.(3)at the central and southwestern PRD cities,the percentage of exceedance days from the continuous type(defined as≥3 days)was ***,the ozone concentration of continuous type was much higher than that of scattered exceedance type(<3 days).In addition,although the occurrence of continuous type starts to decline since2017,the total number of exceedance days during the continuous type is *** results indicate that it is more difficult to eliminate the continuous exceedance than the scatter pollution days and highlight the great challenge in mitigation of O_(3)pollution in these cities.

关键词： Surface ozone pollution Ozone trend Spatial and temporal variability Pearl River Delta Pollution mitigation

Pre-Cryogenian integrative stratigraphy,biotas,and paleogeographical evolution of the Qinghai-Tibetan Plateau and its surrounding areas

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2024年第4期67卷 899-918页

作者： Peiyuan HU Qingguo ZHAI Guochun ZHAO Peter A.CAWOOD Yue TANG yiming liu Institute of Geology Chinese Academy of Geological SciencesBeijing 100037China Department of Earth Sciences University of Hong KongPokfulam RoadHong Kong 999077China State Key Laboratory of Continental Dynamics Department of GeologyNorthwest UniversityXi’an 710069China School of Earth Atmosphere&EnvironmentMonash UniversityMelbourneVIC 3800Australia

The composition and geological evolution of pre-Cryogenian material in the Tibetan Plateau and its surrounding areas have played an important role in studying the formation and evolution of early supercontinents on *** paper systematically summarizes the characteristics of pre-Cryogenian sedimentation,paleontology,magmatism,and metamorphism in the Tibetan Plateau and its surrounding *** on existing data,the records of pre-Cryogenian sedimentation and paleontology are mainly concentrated in the Meso-Neoproterozoic,with relatively few records from the Paleoproterozoic or *** oldest geological record is the Hadean detrital zircons in the metamorphosed sedimentary rocks of the Himalaya and Qamdo areas(ca.4.0 Ga).The Tibetan Plateau and surrounding areas preserve records related to the formation and evolution of the Kenor supercraton,and the Columbia,Rodinia,and Gondwana ***-Cryogenian basements can be divided into three types:Tarim-,Yangtze-,and *** Tarim-type basement has a paleogeographic affinity with the northern margins of the Australian and Indian continents and lacks detrital zircon age peaks and magmatic-metamorphic records related to the Rodinia assembly(ca.1.3-0.9 Ga).The Yangtze-type basement records volcanic activity related to global cooling in the latest pre-Cryogenian period and contains Meso-Neoproterozoic stromatolite and micropaleoflora fossils,as well as magmaticmetamorphic records related to Rodinia assembly(ca.1.1-1.0 Ga).The Lhasa-type basement is characterized by Neoproterozoic rift-related sediment records(ca.900 Ma)and high-pressure metamorphic events(ca.650 Ma),with a prominent peak of detrital zircon ages of ca.1.2-1.1 *** is likely to have a paleogeographic affinity with the African continent.

关键词： Tibetan Plateau Pre-Cryogenian Sedimentation Fossils Paleogeographic evolution

Impact damage testing based on high-speed continuous water jet aircraft coatings

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第10期37卷 249-264页

作者： Minggong SHA Ying SUN Yutong LI yiming liu Gregory FEDOTENKOV Lev RABINSKIY Arseniy BABAYTSEV Yulong LI School of Civil Aviation Northwestern Polytechnical UniversityXi’an 710072China Joint International Research Laboratory of Impact Dynamics and Engineering Application Xi’an 710072China Shaanxi Impact Dynamics and Engineering Application Laboratory Xi’an 710072China NPU Yangzi River Delta Research Institute Suzhou 215400China Moscow Aviation Institute(National Research University) Moscow 125993Russia

When an aircraft passes through a rainy area at high speed,the coating on the front edge of the fuselage will be continuously eroded by raindrops,causing the coating to wear,crack or even peel *** paper uses carbon fiber T300 material as the base material,and at the different impact speeds and impact numbers,water cutting equipment was used to simulate the erosion of the coating caused by the continuous impact of water *** damage morphology of samples at different damage stages was observed by digital microscope and Scanning Electron Microscope(SEM),and the damage evolution curve was established to analyze and reveal the damage behavior and damage mechanism of rain *** results show that the degree of damage experienced an increasing trend with the increase of impact numbers and speed,until circular peel damage was formed;no damage occurred during the incubation period,and the curvature of the damage evolution curve increased significantly after the expansion period and eventually showed a stable expansion *** mechanical properties of the coating material were the main influencing factors of its rain corrosion ***,the axially symmetric unsteady contact problem of droplets impacting the surface of a solid deformable body was *** the contact area was determined based on the iterative algorithm boundary positioning method.A mathematical model and closed mathematical formula describing the unsteady interaction between a droplet and a solid deformable obstacle were proposed.

关键词： Rain erosion damage Liquid-solid impact Multiple jets Composite materials Impact dynamics

Advancing toward the commercial viability threshold of smart windows utilizing thermochromic polymer blends

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Materials 2024年

作者： Lin Yao yiming liu Wei Li China-UK Low Carbon College Shanghai Jiao Tong University Institute for Materials and Processes School of Engineering The University of Edinburgh Edinburgh

Smart materials have demonstrated significant potential for enhancing thermal efficiency and regulating light infiltration within the context of architectural energy management[1].Recent advancements have focused on incorporating thermochromic materials into transparent elements like windows and skylights, facilitating autonomous control of radiative heat transfer in response to external environmental changes and eliminating the need for external energy sources[2].

关键词：

Characteristics of transfer zones under the influence of preexisting faults and regional stress transformation:Wenchang A subsag,Zhujiang River Mouth Basin,northern South China Sea

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Oceanology and Limnology 2024年第3期42卷 744-759页

作者： Wei LI Mingyue CAO Meifang MENG Caiwei FAN Hui LI Jia LI Wanqiu WU Ruiqing QIN Xingan LI yiming liu State Key Laboratory of Deep Oil and Gas China University of Petroleum(East China)Qingdao 266580China School of Geosciences China University of Petroleum(East China)Qingdao 266580China Zhanjiang Branch China National Offshore Oil Corporation CompanyZhanjiang 524057China

A transfer zone in rift basins preserves important information on regional tectonic evolution and plays significant roles in hydrocarbon *** on the systematic analysis of 3D seismic data and hydrocarbon accumulation conditions,the geometry,kinematics,and reservoir control of a large synthetic overlapping transfer zone in the south of the Wenchang A subsag in the Zhujiang(Pearl)River Mouth basin were *** indicate that the development and evolution of the transfer zone was controlled by the interaction between pre-existing faults and regional stress *** intense rifting of the main faults of the transfer zone controlled the development of source rocks and faultcontrolled slope break *** strike-slip overprint since the Oligocene is conducive to the formation of a large-scale fault-anticline trap,and the secondary faults in the transfer zone contribute to the hydrocarbon *** conjugate intersection area of the NE-and NW-trending faults offers more opportunity for hydrocarbon migration and accumulation.

关键词： transfer zone pre-existing fault regional stress transformation Cenozoic Wenchang A Subsag Zhujiang(Pearl)River Mouth Basin

Advances and challenges in semantic communications:A systematic review

在线全文

学校读者我要写书评

暂无评论

National Science Open 2024年第4期3卷 172-207页

作者： Ping Zhang yiming liu Yile Song Jiaxiang Zhang State Key Laboratory of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijing 100876China Department of Broadband Communication Peng Cheng LaboratoryShenzhen 518055China

Inspired by the recent success of machine learning(ML),the concept of semantic communication introduced by Weaver in 1949 has gained significant attention and has become a promising research *** conventional communication systems,semantic communication emphasizes the precise retrieval of conveyed meaning from the source to the receiver,rather than focusing on the accurate transmission of ***,semantic communication can achieve a significant gain in source data compression,alleviate communication bandwidth pressure,and support new intelligent services,which is envisioned as a crucial enabler of future sixth-generation(6G)*** this review,we critically summarize the advances made in semantic information and semantic communications,including theory,architecture,and potential ***,we deeply explore the major challenges in developing semantic communications and present the development prospects,aiming to prompt further scientific and industrial advances in semantic communications.

关键词： semantic communications semantic information 6G artificial intelligence deep learning

在线全文

学校读者我要写书评

暂无评论

个人数据主体收益权的理论迷思与制度选择

学习与实践 2024年第8期 21-31页

作者：袁康刘羿鸣武汉大学法学院湖北武汉430072 武汉大学国家网络安全学院湖北武汉430072

是否应以法定形式明确个人数据主体收益权,当前在理论界存在较大分歧。个人数据在数据价值链中的价值倍增,主要得益于数据处理者而非个人的投入,其体量上的规模性和分布上的碎片化决定了向个人分配收益存在经济性缺失,即设置个人数据主... 详细信息

是否应以法定形式明确个人数据主体收益权,当前在理论界存在较大分歧。个人数据在数据价值链中的价值倍增,主要得益于数据处理者而非个人的投入,其体量上的规模性和分布上的碎片化决定了向个人分配收益存在经济性缺失,即设置个人数据主体收益权缺乏正当性和合理性基础。立法应对个人数据主体收益权采取“原则否定,约定例外”的态度,在个人数据价值的初次分配中放弃个人的法定收益权,但允许其以约定方式取得经济利益。同时,在保障个人数据主体在先权益的前提下,探索数据服务税、数据基金等集体利益实现机制,以体现个人在数据价值分配中的应有地位。

关键词：个人数据主体收益权成本-收益分析在先权益