检索结果-南通市图书馆

Is Participating in MOOC Forums Important for Students？ A Data-driven Study from the Perspective of the Supernetwork

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

Journal of Data and Information Science 2018年第2期3卷 62-77页

作者： chaocheng he panhao ma lusha zhou jiang wu school of information management center for e-commerce research and developmentwuhan universityLuojia MountainWuhan 430072China

Purpose： Compared with traditional course materials used in the classroom, the massive open online course（MOOC） forum that delivers unlimited learning content to students has various advantages. Yet MOOC has also received criticism recently, notably the problem of extremely low participation rates in its discussion forums. This study aims to explore the correlation between forum activity and student course grade in MOOC, and identify more accurately the forum activity levels of participants and the quality of threads in MOOC.Design/Methodology/Approach： We crawled students’ tests, final exams, exercises, discussions performance data and total scores from a course in Chinese College MOOC from May 2014 to August 2014. And we use the data to analyze the correlation between Forum Participation and Course Performance based on nonparametric tests as well as multiple linear regressions with the software of R. The study provides definitions and algorithms of super degrees based on the supernetwork model to help find high-quality threads and active participants.Findings： A positive correlation between forum activity and course grade is found in this study. Students who participate in the forum have better performance than those who do not. Using the definitions and algorithms of super degrees in the supernetwork, forum activity levels of participants as well as the quality of threads they employ are identified. Research limitation： Only limited representative forum participants and threads are used to analyze the activity level and significance of the MOOC forum. Also, the study only investigates one Chinese course on information retrieval. More data and more data sources could be helpful in better understanding the MOOC forum phenomenon.Practical implications： As super degrees can reveal more latent information and recognize high-quality threads as well as active participants, these parameters can be used to assess needs to improve forum settings and alleviate the problem of low forum participation. The proposed super de

关键词： MOOC Participate Forum Supernetwork Super degrees

High spectral efficiency 4-mode 400-km transmission using hybrid probabilistically and geometrically shaped 128QAM

在线全文

学校读者我要写书评

暂无评论

Science China Technological Sciences 2024年第5期67卷 1628-1630页

作者： DING JunJie YU JianJun WANG Chen LONG JianYu ZHU Min ZHANG Jiao Pervasive Communication Research center Purple Mountain Laboratories Key Laboratory for Information Science of Electromagnetic Waves (MoE) Fudan University

Wavelength division multiplexing (WDM) and space division multiplexing (SDM) based on few-mode fiber (FMF)and multi-core fiber (MCF) have been vigorously developed to increase the transmission capacity of optical communication networks [1–5]. However, the mode crosstalk generated in the mode division multiplexing (MDM) system causes the correlation between different mode signals, which seriously damages the transmission performance. Therefore,an effective multiple-input-multiple-output (MIMO) time domain or frequency domain equalizer should be used to eliminate the crosstalk between different mode signals.

关键词： crosstalk fiber multiplexing

Federated Edge Learning for the Wireless Physical Layer:Opportunities and Challenges

在线全文

学校读者我要写书评

暂无评论

China Communications 2022年第8期19卷 15-30页

作者： Yiming Cui Jiajia Guo Xiangyi Li Le Liang Shi Jin National Mobile Communications Research Laboratory and Frontiers Science center for Mobile Information Communication and Security Southeast UniversityNanjing 210096China Purple mountain Laboratories Nanjing 211111China

Deep learning(DL)has been applied to the physical layer of wireless communication systems,which directly extracts environment knowledge from data and outperforms conventional methods either in accuracy or computation complexity.However,most related research works employ centralized training that inevitably involves collecting training data from edge devices.The data uploading process usually results in excessive communication overhead and privacy disclosure.Alternatively,a distributed learning approach named federated edge learning(FEEL)is introduced to physical layer designs.In FEEL,all devices collaborate to train a global model only by exchanging parameters with a nearby access point.Because all datasets are kept local,data privacy is better protected and data transmission overhead can be reduced.This paper reviews the studies on applying FEEL to the wireless physical layer including channel state information acquisition,transmitter,and receiver design,which represent a paradigm shift of the DL-based physical layer design.In the meantime they also reveal several limitations inherent in FEEL,particularly when applied to the wireless physical layer,thus motivating further research efforts in the field.

关键词： deep learning federated edge learning wireless communication physical layer

Mannogalactoglucan from mushrooms protects pancreatic islets via restoring UPR and promotes insulin secretion in TIDM mice

在线全文

学校读者我要写书评

暂无评论

Food Science and Human Wellness 2024年第3期13卷 1390-1401页

作者： Ting Liu Si Chen Yunhe Qu Lujuan Zheng Xiaoxuan Yang Shuhan Men Yuanning Wang Hanrui Ma Yifa Zhou Yuying Fan Engineering Research center of Glycoconjugates Ministry of EducationJilin Provincial Key Laboratory of Chemistry and Biology of Changbai Mountain Natural DrugsSchool of Life SciencesNortheast Normal UniversityChangchun 130024China

Type 1 diabetes mellitus(T1DM) lacks insulin secretion due to autoimmune deficiency of pancreaticβ-cells.Protecting pancreatic islets and enhancing insulin secretion has been therapeutic approaches.Mannogalactoglucan is the main type of polysaccharide from natural mushroom,which has potential medicinal prospects.Nevertheless,the antidiabetic property of mannogalactoglucan in T1DM has not been fully elucidated.In this study,we obtained the neutral fraction of alkali-soluble Armillaria mellea polysaccharide(AAMP-N) with the structure of mannogalactoglucan from the fruiting body of A.mellea and investigated the potential therapeutic value of AAMP-N in T1DM.We demonstrated that AAMP-N lowered blood glucose and improved diabetes symptoms in T1DM mice.AAMP-N activated unfolded protein response(UPR) signaling pathway to maintain ER protein folding homeostasis and promote insulin secretion in vivo.Besides that,AAMP-N promoted insulin synthesis via upregulating the expression of transcription factors,increased Ca^(2+) signals to stimulate intracellular insulin secretory vesicle transport via activating calcium/calmodulin-dependent kinase Ⅱ(CamkⅡ) and cAMP/PKA signals,and enhanced insulin secretory vesicle fusion with the plasma membrane via vesicle-associated membrane protein 2(VAMP2).Collectively,these studies demonstrated that the therapeutic potential of AAMP-N on pancreatic islets function,indicating that mannogalactoglucan could be natural nutraceutical used for the treatment of T1DM.

关键词： Mannogalactoglucan Mushroom Pancreatic islets Insulin secretion Insulin synthesis Unfolded protein response(UPR) Type 1 diabetes mellitus(T1DM)

Threshold criterion for debris flow initiation in seasonal gullies

在线全文

学校读者我要写书评

暂无评论

International Journal of Sediment Research 2017年第2期32卷 231-239页

作者： Yang Wang Peng Cui Zhaoyin Wang Shuangqing Liang Key Laboratory of mountain Hazards and Earth Surface Processes/Institute of mountain Hazards and Environment CAS University of Chinese Academy of Sciences CAS center for Excellence in Tibetan Plateau Earth Sciences Department of Hydraulic Engineering Tsinghua University

A series of flume experiments were done to investigate the effect of grain composition on the critical gradient and discharge of debris flows initiated in seasonal gullies.The results indicated that the critical gradient and discharge for debris flow initiation decrease initially,and then increase as the mass content of fine particles(< 2 mm) increases.As the mass content of fine particles increases,the angle of repose,permeability of widely graded gravel soils,and the incipient motion conditions of the coarse grains in non-uniform sediments decrease at first,and then increase.The mass content of fine particles of all inflection points is the same.The theoretical model based on the combination of hydrodynamic force and shear stress is more applicable to the prediction of the critical gradient for debris flow initiation.The critical discharge model considering the effect of non-homogeneity of the soil and the size of coarse and fine grains provides a more accurate prediction of debris flow initiation than other models based on the mean diameter.

关键词： Grain composition Seasonal gully Non-uniform sediment Debris flow initiation Critical gradient Critical discharge

Developing a sustainable strategy to conserve reservoir marginal landscapes

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

National Science Review 2018年第1期5卷 10-14页

作者： Qiang Tang Bojie Fu Adrian L.Collins Anbang Wen Xiubin He Yuhai Bao Key Laboratory of mountain Surface Processes and Ecological Regulation Institute of Mountain Hazards and Environment Chinese Academy of Sciences State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of Sciences

China has accelerated its pace in building dams to meet growing demands in energy consumption,as well as to alleviate air pollution resulting from fossil fuel emissions and to mitigate global climate change impacts.Large rivers in southwestern China(i.***.the Jinsha,Yalong,Dadu,Wu,Nu,Lancang and upper Yangtze rivers)have primarily been targeted as major basins for hydropower development,where cascade dams have been constructed or are proposed.Among them,the Three Gorges Dam is the world’s largest hydropower project

关键词： Developing a sustainable strategy to conserve reservoir marginal landscapes

The formation of a blue cluster in the local Universe

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2020年第12期20卷 337-346页

作者：温庆新罗煜康熙 Purple mountain Observatory Chinese Academy of SciencesNanjing 210033China School of Astronomy and Space Sciences University of Science and Technology of ChinaHefei 230026China Zhejiang University-Purple mountain Observatory Joint Research center for Astronomy Zhejiang UniversityHangzhou 310037China

It is well known from the Butcher-Oemler effect that galaxies in dense environment are mostly red with little star formation and the fraction of blue galaxies in galaxy groups/clusters also declines rapidly with redshifts.A recent work by Hashimoto et al.reported a local ‘blue cluster’ with a high fraction of blue galaxies(∼0.57),higher than the model predictions.They ascribed this blue cluster to the feeding of gas along a filamentary structure around the cluster.In this work we use group catalog from the Sloan Digital Sky Survey Data Release 7(SDSS DR7) and the state-of-art of semi-analytic model(SAM) to investigate the formation of blue clusters in the local Universe.In total,we find four blue clusters with halo mass ∼10^14 M⊙ at 0.02

关键词： galaxies:clusters:statistical galaxies:evolution galaxies:formation galaxies:blue fraction

A circular approach for sustainable agriculture and human health

在线全文

学校读者我要写书评

暂无评论

Circular Agricultural Systems 2021年第1期1卷 37-38页

作者： Jianchu Xu Center for Mountain Futures Kunming Institute of BotanyChinese Academy of SciencesKunming 650201China CIFOR-ICRAF China Program World Agroforestry CentreKunming 650201China State Key Laboratory of Animal Nutrition Institute of Animal SciencesChinese Academy of Agricultural SciencesBeijing 100081China

In the 21st century,global food systems cannot remain stuck in the past.Agriculture currently contributes about one fourth of global greenhouse gas emissions and about half of all nutrient wastes annually[1].As the number of humans on the planet continues to grow,the effects of climate change will worsen and ecosystems will continue to deteriorate.Innovation in today’s agricultural food production systems is therefore urgently needed to increase crop and animal outputs,enhance dietary diversity and improve human health while conserving environments and sustaining natural resources and cultures.

关键词： annually continue circular

Coseismic landslide sediment increased by the“9.5”Luding earthquake,Sichuan,China

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

Journal of mountain Science 2023年第3期20卷 624-636页

作者： XIONG Jiang CHEN Hua-yong ZENG Lu SU Feng-huan GONG Ling-feng TANG Chen-xiao Key Laboratory of mountain Hazards and Earth Surface Processes Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610299China Chengdu Geological Survey center China Geological SurveyChengdu 610081China

The"9.5"Luding earthquake(Ms 6.8),which occurred on September 5,2022,has triggered thousands of landslides,and caused coseismic landslide sediment in the mountain basin to increase significantly.After the Luding earthquake,landslide sediment may continue to divert to channels,and increase the activity of debris flows.Importantly,the formation of debris flows can pose a major threat to infrastructure,lives and property.To better understand the landslide sediment that increased by the"9.5"Luding earthquake and its impact on the activity of debris flows,we mapped the coseismic landslide database using satellite images.A total of9142 landslides with an area of 49.51 km^(2),covering4.81%of the whole basin,were triggered by the Luding earthquake.The coseismic landslides induced by this earthquake are dominated by shallow landslides and are densely distributed in the combined zone of the Xianshuihe fault and the Daduhe fault.Approximately 333.31×10^(6)m^(3)(error:111.43×10^(6)m^(3)/-70.73×10^(6)m^(3))of coseismic landslide sediments were induced by the earthquake in the epicenter,and the landslide materials were concentrated downstream of the basins.In addition.more than 13986.45×10^(4)m^(3)(error:4675.67×10^(4)m^(3)/-2967.92×10^(4)m^(3))of landslide sediment may supply for debris flow occurrence.Simultaneously,the small basins that are distributed near Moxi,Detuo and the junction of the Xianshuihe fault and Daduhe fault are more susceptible to debris flows when rainstorms hit these regions.Therefore,prevention and mitigation measures,early warning,and land use planning should be adopted in advance in these regions.However,from the perspectives of landslide scale and the degree of landslide-channel coupling,the activity or active intensity of debris flows in the Luding earthquake area may be lower than that in the epicenter area of the 2008 Wenchuan earthquake.

关键词： Luding earthquake Landslide sediment Debris flow activity Remote sensing image