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Efficient Computation Offloading in Mobile cloud Computing for Video Streaming Over 5G

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Computers, Materials & Continua 2019年第8期61卷 439-463页

作者： Bokyun Jo MdJalil Piran Daeho Lee Doug Young Suh DEE Kyung Hee UniversityYongin17104South Korea DCSE Sejong UniversitySeoul05006South Korea

In this paper,we investigate video quality enhancement using computation offloading to the mobile cloud computing(MCC)*** objective is to reduce the computational complexity required to covert a low-resolution video to high-resolution video while minimizing computation at the mobile client and additional communication *** do so,we propose an energy-efficient computation offloading framework for video streaming services in a MCC over the fifth generation(5G)cellular *** the proposed framework,the mobile client offloads the computational burden for the video enhancement to the cloud,which renders the side information needed to enhance video without requiring much computation by the *** cloud detects edges from the upsampled ultra-high-resolution video(UHD)and then compresses and transmits them as side information with the original low-resolution video(e.g.,full HD).Finally,the mobile client decodes the received content and integrates the SI and original content,which produces a high-quality *** our extensive simulation experiments,we observed that the amount of computation needed to construct a UHD video in the client is 50%-60% lower than that required to decode UHD video compressed by legacy video encoding ***,the bandwidth required to transmit a full HD video and its side information is around 70% lower than that required for a normal UHD *** subjective quality of the enhanced UHD is similar to that of the original UHD video even though the client pays lower communication costs with reduced computing power.

关键词： 5G video streaming cloud computation offloading energy efficiency upsampling MOS

Observations of the field-aligned residual flow inside magnetic cloud structure

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Science China(Technological Sciences) 2009年第9期52卷 2555-2566页

作者： LI HuiJun FENG XueShang ZUO PingBing XIE YanQiong SIGMA Weather Group State Key Laboratory for Space WeatherCenter for Space Science and Applied ResearchChinese Academy of SciencesBeijing 100190China Graduate University of the Chinese Academy of Sciences Beijing 100039China Institute of Meteorology PLA University of Science and TechnologyNanjing 211101China

In this paper,we report two MC events observed by WIND spacecraft with good examples of fieldaligned residual flow inside the MC structure. For both events,the co-moving frames are determined through the deHoffman-Teller (HT) analysis and the axial orientations are inferred by the newly developed minimal residue (MR) method. The nature coordinate system for both events are constructed with velocity of the HT frame and the inferred MC axis,the field and flow remaining in the HT frame are analyzed at this coordinate system. As a result,we find that the residual flows in the co-moving HT frame of the two MC events are almost anti-parallel to the helical magnetic field. We speculate that the field-aligned residual flows are large scale coherent hydrodynamic vortices co-moving with the MCs at the supersonic speed near 1 AU. Data analyses show that the event in slow ambient solar wind is expanding at 1 AU and another one in fast solar wind does not show apparent expansion. Proton behaviors for both events are quasi-isothermal. Accelerated HT analysis shows that both events have no suitable HT frame with constant accelerations,which suggests that both events may be moving at the constant speed near 1 AU under the assumptions of the HT analysis. For both events,the ratio of the dynamic pressure to the magnetic pressure is larger than that of the thermal pressure to magnetic pressure,which suggests that the dynamic effects due to the plasma flows remaining in the co-moving HT frame are more important than the thermal effects in the study of MC evolution and propagation.

关键词： interplanetary medium solar wind magnetic cloud (MC) Sun:coronal mass ejections (CMEs)

Audio Highlight Detection Method for cloud-Based Multimedia Service System

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China Communications 2011年第6期8卷 51-57页

作者：李祺徐国爱田斌张淼 lnformntion Security Center Beijing University of Posts and Telecommunications National Engineering Laboratory for Disaster Backup and Recovery Beijing University of Posts and Telecommunications

With the development of cloud-based data centers and multimedia technologies, cloud-based multimedia service systems have been paid more and more attention. Audio highlights detection plays an important role in the cloud-based multimedia service system. In this paper, we proposed a novel highlight detection method to extract the audio highlight effects for the cloud-based multimedia service system using the unsupervised approach. In the proposed method, we first extract the audio features for each audio document. Then the spectral clustering scheme was used to decompose the audio document into several audio effects. Then, we introduce the TF-IDF method to label the highlight effect. We design some experiments to evaluate the performance of the proposed method, and the experimental results show that our method can achieve satisfying results.

关键词： cloud multimedia service system audio highlight detection audio content analysis unsupervised approach

Numerical simulation on the evolution of cloud particles in 3-D convective cloud

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Science China Earth Sciences 2009年第8期52卷 1195-1206页

作者： XiaoLi Liu ShengJie Niu Key Laboratory of Meteorological Disaster of Ministry of Education School of Atmospheric Physics Nanjing University of Information Science & Technology Nanjing 210044 China

A 3-D convective cloud model with compressible non-hydrostatic dynamics and the spectral bin microphysics of a 2-D slab-symmetric model has been used to simulate an observed supercell storm occurring on 29 June, 2000 ... 详细信息

关键词： spectral bin microphysics 3-D convective cloud numerical simulation evolution of particle spectrum

Performance of CAMS-CSM in Simulating the Shortwave cloud Radiative Effect over Global Stratus cloud Regions: Baseline Evaluation and Sensitivity Test

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Journal of Meteorological Research 2019年第4期33卷 651-665页

作者： Yihui ZHOU Yi ZHANG Xinyao RONG Jian LI Rucong YU State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029 University of Chinese Academy of Sciences Beijing 100049 State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100081

The ability of climate models to correctly reproduce clouds and the radiative effects of clouds is vitally important in climate simulations and *** this study,simulations of the shortwave cloud radiative effect(SWCRE)using the Chinese Academy of Meteorological Sciences Climate System Model(CAMS-CSM)are *** relationships between SWCRE and dynamic–thermodynamic regimes are examined to understand whether the model can simulate realistic processes that are responsible for the generation and maintenance of stratus *** eastern China,CAMS-CSM well simulates the SWCRE climatological state and stratus cloud *** model captures the strong dependence of SWCRE on the dynamic *** the marine boundary layer regions,the simulated SWCRE magnitude is weaker than that in the observations due to the lack of low-level stratus clouds in the *** model fails to simulate the close relationship between SWCRE and local stability over these regions.A sensitivity numerical experiment using a specifically designed parameterization scheme for the stratocumulus cloud cover confirms this *** schemes that directly depict the relationship between the stratus cloud amount and stability are beneficial for improving the model performance.

关键词： Chinese Academy of Meteorological Sciences Climate System Model (CAMS-CSM) shortwave cloudradiative effect (SWCRE) stratus cloud model errors

The spectra and temperature of cloud lightning discharge channel

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Science China Earth Sciences 2009年第7期52卷 907-912页

作者： WANG Jie YUAN Ping GUO FengXia QIE XiuShu OUYANG YuHua ZHANG YiJun College of Physics and Electronic Engineering Northwest Normal UniversityLanzhou 730070China Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of SciencesLanzhou 730000China Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China Chinese Academy of Meteorological Sciences Beijing 100081China

Spectra of seven cloud lightning discharges are reported for the first time after captured with a Slit-less Spectrograph on Chinese Tibet Plateau. The structural characters are analyzed and compared with the spectra of cloud-to-ground lightning, and the results indicate that the spectra of cloud lightning show two different kinds of structure characteristics. One has the similar structure as those of cloud-to-ground lightning discharge, and the other is absolutely different. Meanwhile, more lines of OII with high excited energy are recorded in the spectra of cloud lightning discharge in comparison with that of cloud-to-ground lighting happening in the same region. Temperatures at different positions are calculated and temperature characteristics of these two sorts are analyzed, based to the wavelength, relative intensities and other transition parameters. We suggest that the physical process in the cloud discharge channels changes with much more rapid velocity and wider range compared to cloud-to-ground lightning. The differences between the two types of cloud discharge also reflect some discrepancies between the discharge characteristics.

关键词： spectra cloud lightning discharge temperature

Satellite-based Observational Study of the Tibetan Plateau Vortex:Features of Deep Convective cloud Tops

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Advances in Atmospheric Sciences 2019年第2期36卷 189-205,248页

作者： Yi-Xuan SHOU Feng LU Hui LIU Peng CUI Shaowen SHOU Jian LIU Key Laboratory of Radiometric Calibration and Validation for Environmental Satellites China Meteorological Administration(LRCVES/CMA) National Satellite Meteorological Center Key Laboratory of Meteorological Disasters Nanjing University of Information Sciences and Technology

In this study, an east-moving Tibetan Plateau vortex(TPV) is analyzed by using the ERA-5 reanalysis and multi-source satellite data, including FengYun-2 E, Aqua/MODIS and CALIPSO. The objective is to demonstrate:(i) the usefulness of multi-spectral satellite observations in understanding the evolution of a TPV and the associated rainfall, and(ii) the potential significance of cloud-top quantitative information in improving Southwest China weather forecasts. Results in this study show that the heavy rainfall is caused by the coupling of an east-moving TPV and some low-level weather systems [a Plateau shear line and a Southwest Vortex(SWV)], wherein the TPV is a key component. During the TPV's life cycle, the rainfall and vortex intensity maintain a significant positive correlation with the convective cloud-top fraction and height within a 2.5?radius away from its center. Moreover, its growth is found to be quite sensitive to the cloud phases and particle sizes. In the mature stage when the TPV is coupled with an SWV, an increase of small ice crystal particles and appearance of ring-and U/V-shaped cold cloud-top structures can be seen as the signature of a stronger convection and rainfall enhancement within the TPV. A tropopause folding caused by ageostrophic flows at the upper level may be a key factor in the formation of ring-shaped and U/V-shaped cloud-top structures. Based on these results, we believe that the supplementary quantitative information of an east-moving TPV cloud top collected by multi-spectral satellite observations could help to improve Southwest China short-range/nowcasting weather forecasts.

关键词： Tibetan Plateau vortex multi-spectral satellite observations short-range/nowcasting weather forecasts cold U/V-shaped cloud top tropopause folding

Study on the clouds Detected by a Millimeter-Wave cloud Radar over the Hinterland of the Taklimakan Desert in April–June 2018

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Journal of Meteorological Research 2021年第6期35卷 1074-1090页

作者： Hu MING Minzhong WANG Ming WEI Yinjun WANG Xiaochen HOU Mingliang GAO School of Electrical&Electronic Engineering Shandong University of TechnologyZibo 255000 Taklimakan Desert Meteorology Field Experiment Station of CMA Institute of Desert MeteorologyChina Meteorological Administration(CMA)Urumqi 830002 Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing 210044 State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100081

This study was the first to conduct high-resolution consecutive detection of clouds over the hinterland of the Taklimakan Desert(TD)from April to June 2018 based on a ground-based Ka-band millimeter-wave cloud radar(MMCR),with focus on the structure and evolution of the desert *** calculated reflectivity factor(Z),cloud boundary,and liquid water content(LWC)by use of the MMCR power spectrum data,which were verified against the observations from cloud profile radar(CPR)on board cloud *** results show that the TD clouds were mostly medium and high clouds,with thickness generally less than 2 km;moreover,the mean LWCs of these clouds were less than 0.01 gm^(-3),implying that cirrus and stratiform clouds were *** the observed low clouds,however,the average thickness was 3166 m and accompanying drizzles were concentrated within 2.5-4.5 km,indicating that precipitation was more likely to occur in the low *** mean LWC in the TD clouds was 0.0196 gm^(-3),less than that of clean *** to other periods,the average durations and LWCs in the TD clouds increased significantly around noon owing to obvious surface sensible *** average time for evolution of high clouds into low clouds was approximately 2 h,and the average maximum LWC increased from 0.008 to 0.139 gm;.The results obtained herein provide a key reference for further studies of the structure and evolution characteristics of the desert clouds.

关键词： millimeter-wave radar reflectivity factor(Z) liquid water content cloud the hinterland of the Taklimakan Desert

OpenRS-cloud:A remote sensing image processing platform based on cloud computing environment

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Science China(Technological Sciences) 2010年第S1期53卷 221-230页

作者： GUO Wei,GONG JianYa,JIANG WanShou,LIU Yi & SHE Bing State Key Laboratory for Information Engineering in Surveying,Mapping and Remote Sensing,Wuhan University,Wuhan 430074,China State Key Laboratory for Information Engineering in Surveying Mapping and Remote Sensing Wuhan University Wuhan China

This paper explores the use of cloud computing for remote sensing image *** main contribution of our work is to develop a remote sensing image processing platform based on cloud computing technology(OpenRS-cloud).This paper focuses on enabling methodical investigations into the development pattern,computational model,data management and service model exploring this novel distributed computing *** experimental INSAR processing flow is implemented to verify the efficiency and feasibility of OpenRS-cloud *** results show that cloud computing is well suited for computationally-intensive and data-intensive remote sensing services.

关键词： remote sensing cloud computing MapReduce parallel computing web service