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Microphysical Properties of Convective Clouds in Summer over the Tibetan Plateau from SNPP/VⅡRS Satellite Data
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作者 Zhiguo YUE Xing YU +5 位作者 Guihua LIU Jin DAI Yannian ZHU Xiaohong XU Ying HUI Chuang CHEN 《气象学报:英文版》 SCIE CSCD 2019年第3期433-445,共13页
The Tibetan Plateau (TP) plays an important role in formation and development of the East Asian atmospheric circulation, climate variability, and disastrous weathers in China. Among the many topics on TP meteorology, ... The Tibetan Plateau (TP) plays an important role in formation and development of the East Asian atmospheric circulation, climate variability, and disastrous weathers in China. Among the many topics on TP meteorology, it is critical to understand the microphysical characteristics of clouds over the TP;however, observations of the cloud microphysics in this area are insufficient mainly due to sparse stations and limited cloud physical data. The Visible Infrared Imaging Radiometer Suite (VⅡRS), onboard the Suomi National Polar-orbiting Partnership (SNPP) satellite, has an improved imaging spectroradiometer with 17 channels of 750-m moderate resolution and 5 channels of 375-m image resolution. The high-resolution instrument has an advantage for observing the small or initial convective clouds. Based on the methodologies that we proposed before for retrieving cloud microphysical properties from SNPP, an automated mapping software package named Automatic Mapping of Convective Clouds (AMCC) has been developed at the scale of satellite swath. The properties of convective clouds are retrieved by AMCC and their values are averaged over 0.33°×0.33° grids based on the SNPP/VⅡRS satellite data over the TP during the summers of 2013-17. The results show that:(1) the temperature of lifting condensation level (TLCL) at Naqu meteorological station and the cloud base temperature (Tb) retrieved from VⅡRS are linearly correlated, with a correlation coefficient of 0.87 and standard deviation (STD) of 3.0℃;(2) convective clouds over the TP have the following macro-and microphysical properties. First, the cloud base temperature (Tb) is about -5℃, the cloud base height above the ground (Hb) ranges between 1800 and 2200 m, and the cloud water content is low. Second, the cloud condensation nuclei concentration (NCCN) is between 200 and 400 mg-1 with 0.7% in maximum supersaturation (Smax);consequently, the condensation growth of water cloud droplet with less NCCN and higher Smax is fast. Third, because the precipitation initia 展开更多
关键词 Tibetan Plateau Visible Infrared Imaging RADIOMETER SUITE (VⅡRS) retrieval of CLOUD microphysical properties CONVECTIVE CLOUD CLOUD base temperature CLOUD condensation nuclei
LASG Global AGCM with a Two-moment Cloud Microphysics Scheme:Energy Balance and Cloud Radiative Forcing Characteristics 预览
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作者 Lei WANG Qing BAO +9 位作者 Wei-Chyung WANG Yimin LIU Guo-Xiong WU Linjiong ZHOU JiANDong LI Hua GONG Guokui NIAN Jinxiao LI Xiaocong WANG Bian HE 《大气科学进展:英文版》 SCIE CAS CSCD 2019年第7期697-710,共14页
Cloud dominates influence factors of atmospheric radiation, while aerosol–cloud interactions are of vital importance in its spatiotemporal distribution. In this study, a two-moment(mass and number) cloud microphysics... Cloud dominates influence factors of atmospheric radiation, while aerosol–cloud interactions are of vital importance in its spatiotemporal distribution. In this study, a two-moment(mass and number) cloud microphysics scheme, which significantly improved the treatment of the coupled processes of aerosols and clouds, was incorporated into version 1.1 of the IAP/LASG global Finite-volume Atmospheric Model(FAMIL1.1). For illustrative purposes, the characteristics of the energy balance and cloud radiative forcing(CRF) in an AMIP-type simulation with prescribed aerosols were compared with those in observational/reanalysis data. Even within the constraints of the prescribed aerosol mass, the model simulated global mean energy balance at the top of the atmosphere(TOA) and at the Earth’s surface, as well as their seasonal variation, are in good agreement with the observational data. The maximum deviation terms lie in the surface downwelling longwave radiation and surface latent heat flux, which are 3.5 W m-2(1%) and 3 W m-2(3.5%), individually. The spatial correlations of the annual TOA net radiation flux and the net CRF between simulation and observation were around 0.97 and 0.90, respectively. A major weakness is that FAMIL1.1 predicts more liquid water content and less ice water content over most oceans. Detailed comparisons are presented for a number of regions, with a focus on the Asian monsoon region(AMR). The results indicate that FAMIL1.1 well reproduces the summer–winter contrast for both the geographical distribution of the longwave CRF and shortwave CRF over the AMR. Finally, the model bias and possible solutions, as well as further works to develop FAMIL1.1 are discussed. 展开更多
关键词 two-moment CLOUD MICROPHYSICS SCHEME aerosol–cloud interactions energy balance CLOUD radiative forcing Asian monsoon region
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Cloud service selection using cloud service brokers: approaches and challenges
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作者 Meysam VAKILI Neda JAHANGIRI Mohsen SHARIFI 《中国计算机科学前沿:英文版》 SCIE EI CSCD 2019年第3期599-617,共19页
Cloud computing users are faced with a wide variety of services to choose from. Consequently, a number of cloud service brokers (CSBs) have emerged to help users in their service selection process. This paper reviews ... Cloud computing users are faced with a wide variety of services to choose from. Consequently, a number of cloud service brokers (CSBs) have emerged to help users in their service selection process. This paper reviews the recent approaches that have been introduced and used for cloud service brokerage and discusses their challenges accordingly. We propose a set of attributes for a CSB to be considered effective. DifFerent CSBs' approaches are classified as either single service or multiple service models. The CSBs are then assessed, analyzed, and compared with respect to the proposed set of attributes. Based on our studies, CSBs with multiple service models that support more of the proposed effective CSB attributes have wider application in cloud computing environments. 展开更多
关键词 CLOUD SERVICE BROKER (CSB) CLOUD SERVICE SELECTION CLOUD computing quality of SERVICE (QoS)
基于卫星遥感的祁连山及甘肃中部地区云宏观特征
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作者 宋琦明 张武 +4 位作者 苏亚乔 陈艳 杨昆 赵桂清 曹刚 《干旱区研究》 CSCD 北大核心 2019年第3期712-722,共11页
利用2007—2010年Cloud Sat和CALIPSO卫星遥感资料以及中国国家气象信息中心(CMDC)提供的地面降水资料(1996—2016年),对祁连山区、甘肃中部及石羊河流域的不同云类型宏观特征进行了分析。结果表明:各研究区域总云分数的季节变化较一致... 利用2007—2010年Cloud Sat和CALIPSO卫星遥感资料以及中国国家气象信息中心(CMDC)提供的地面降水资料(1996—2016年),对祁连山区、甘肃中部及石羊河流域的不同云类型宏观特征进行了分析。结果表明:各研究区域总云分数的季节变化较一致,较大值出现在春夏季,均超过70%。总云分数的高值区主要集中在祁连山南坡,与降水量高值区分布一致。积状云云分数最大值出现在夏季,积状云降水频率高于层状云。云层以单层云为主,云厚度均超过2.0 km,春季甘肃中部的单层云厚度最大达3.0 km;2层云夹层比3层云的夹层厚度要厚。产生降水的云中积状云和单层云的发生频率较高。各区域云频率随高度分布趋势大致相同,层状云出现的高度在距地表0.5 km到12.0 km,云频率峰值均在高度6.0 km左右出现;积状云云频率随高度分布较层状云明显偏低,峰值出现在1.5km左右高度。 展开更多
关键词 降水 CLOUD SAT CALIPSO 祁连山 甘肃
云:一个古典意象的文化剖析 预览
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作者 侯智芳 吴丽君 崔英杰 《河北北方学院学报:社会科学版》 2019年第2期16-19,共4页
受黄帝文化的影响,云意象具有盛世吉祥、士子命运和亲友眷恋等3方面的内涵。从黄帝文化的角度剖析云意象,探讨黄帝文化与云意象的联系,对研究黄帝文化和云意象都有积极的推动作用。
关键词 黄帝文化 古典意象 文化剖析
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Generic attribute revocation systems for attribute-based encryption in cloud storage
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作者 Genlang CHEN Zhiqian XU +3 位作者 Jia-jian ZHANG Guo-jun WANG Hai JIANG Miao-qing HUANG 《信息与电子工程前沿:英文版》 SCIE EI CSCD 2019年第6期773-786,共14页
Attribute-based encryption(ABE) has been a preferred encryption technology to solve the problems of data protection and access control, especially when the cloud storage is provided by third-party service providers.AB... Attribute-based encryption(ABE) has been a preferred encryption technology to solve the problems of data protection and access control, especially when the cloud storage is provided by third-party service providers.ABE can put data access under control at each data item level. However, ABE schemes have practical limitations on dynamic attribute revocation. We propose a generic attribute revocation system for ABE with user privacy protection. The attribute revocation ABE(AR-ABE) system can work with any type of ABE scheme to dynamically revoke any number of attributes. 展开更多
关键词 ATTRIBUTE-BASED ENCRYPTION GENERIC ATTRIBUTE REVOCATION User PRIVACY Cloud storage Access control
华为携多厂商发起双G Cloud VR倡议 掀产业规模商用大潮 预览
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作者 黄海峰 《通信世界》 2019年第11期13-14,共2页
移动互联网和智能手机之后,科技领域的新千亿蓝海市场是什么?很多人认为VR和AR是其中重要方向,且是离我们最近的机会点。目前全球VR/AR产业保持高速发展,已经成为ICT产业持续创新的关键驱动力之一。IDC预测,2019年全球AR/VR市场空间将超... 移动互联网和智能手机之后,科技领域的新千亿蓝海市场是什么?很多人认为VR和AR是其中重要方向,且是离我们最近的机会点。目前全球VR/AR产业保持高速发展,已经成为ICT产业持续创新的关键驱动力之一。IDC预测,2019年全球AR/VR市场空间将超过20 4亿美元,同时未来3年仍将保持69.6%的年复合增长率。 展开更多
关键词 G CLOUD VR 运营商 产业生态 接入速率 商业解决方案 福建公司
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A secure data sharing scheme with cheating detection based on Chaum-Pedersen protocol for cloud storage
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作者 Xin WANG Bo YANG +1 位作者 Zhe XIA Hong-xia HOU 《信息与电子工程前沿:英文版》 SCIE EI CSCD 2019年第6期787-800,共14页
With the development of cloud computing technology, data can be outsourced to the cloud and conveniently shared among users. However, in many circumstances, users may have concerns about the reliability and integrity ... With the development of cloud computing technology, data can be outsourced to the cloud and conveniently shared among users. However, in many circumstances, users may have concerns about the reliability and integrity of their data. It is crucial to provide data sharing services that satisfy these security requirements. We introduce a reliable and secure data sharing scheme, using the threshold secret sharing technique and the ChaumPedersen zero-knowledge proof. The proposed scheme is not only effective and flexible, but also able to achieve the semantic security property. Moreover, our scheme is capable of ensuring accountability of users’ decryption keys as well as cheater identification if some users behave dishonestly. The efficiency analysis shows that the proposed scheme has a better performance in terms of computational cost, compared with the related work. It is particularly suitable for application to protect users’ medical insurance data over the cloud. 展开更多
关键词 Data SHARING Chaum- Pedersen PROOF CHEATING det ection CLOUD storage
Driftor: mitigating cloud-based side-channel attacks by switching and migrating multi-executor virtual machines
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作者 Chao YANG Yun-fei GUO +3 位作者 Hong-chao HU Ya-wen WANG Qing TONG Ling-shu LI 《信息与电子工程前沿:英文版》 SCIE EI CSCD 2019年第5期731-748,共18页
Co-residency of different tenants’ virtual machines(VMs) in cloud provides a good chance for side-channel attacks, which results in information leakage. However, most of current defense suffers from the generality or... Co-residency of different tenants’ virtual machines(VMs) in cloud provides a good chance for side-channel attacks, which results in information leakage. However, most of current defense suffers from the generality or compatibility problem, thus failing in immediate real-world deployment. VM migration, an inherit mechanism of cloud systems, envisions a promising countermeasure, which limits co-residency by moving VMs between servers. Therefore, we first set up a unified practical adversary model, where the attacker focuses on effective side channels. Then we propose Driftor, a new cloud system that contains VMs of a multi-executor structure where only one executor is active to provide service through a proxy, thus reducing possible information leakage. Active state is periodically switched between executors to simulate defensive effect of VM migration. To enhance the defense, real VM migration is enabled at the same time. Instead of solving the migration satisfiability problem with intractable CIRCUIT-SAT, a greedy-like heuristic algorithm is proposed to search for a viable solution by gradually expanding an initial has-to-migrate set of VMs. Experimental results show that Driftor can not only defend against practical fast side-channel attack, but also bring about reasonable impacts on real-world cloud applications. 展开更多
关键词 Cloud computing Side-channel ATTACK Information leakage Multi-executor structure VIRTUAL MACHINE switch VIRTUAL MACHINE migration
On Cost Aware Cloudlet Placement for Mobile Edge Computing 预览
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作者 Qiang Fan Nirwan Ansari 《自动化学报:英文版》 CSCD 2019年第4期926-937,共12页
As accessing computing resources from the remote cloud inherently incurs high end-to-end(E2E)delay for mobile users,cloudlets,which are deployed at the edge of a network,can potentially mitigate this problem.Although ... As accessing computing resources from the remote cloud inherently incurs high end-to-end(E2E)delay for mobile users,cloudlets,which are deployed at the edge of a network,can potentially mitigate this problem.Although some research works focus on allocating workloads among cloudlets,the cloudlet placement aiming to minimize the deployment cost(i.e.,consisting of both the cloudlet cost and average E2E delay cost)has not been addressed effectively so far.The locations and number of cloudlets have a crucial impact on both the cloudlet cost in the network and average E2E delay of users.Therefore,in this paper,we propose the Cost Aware cloudlet PlAcement in moBiLe Edge computing(CAPABLE)strategy,where both the cloudlet cost and average E2E delay are considered in the cloudlet placement.To solve this problem,a Lagrangian heuristic algorithm is developed to achieve the suboptimal solution.After cloudlets are placed in the network,we also design a workload allocation scheme to minimize the E2E delay between users and their cloudlets by considering the user mobility.The performance of CAPABLE has been validated by extensive simulations. 展开更多
关键词 CLOUDLET PLACEMENT MOBILE cloud COMPUTING MOBILE EDGE COMPUTING
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长三角地区气溶胶对辐射和降水影响的分析
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作者 陆天蔚 张晶 +2 位作者 乔岩 薛文晧 周丽花 《北京师范大学学报:自然科学版》 CAS CSCD 北大核心 2019年第1期135-144,共10页
为深入研究长三角地区气溶胶对辐射和降水的影响,本文分析了2004—2014年该区气溶胶光学厚度(aerosol optical depth,AOD)、辐射和降水的时空变化特征,在季节尺度确定了对辐射和降水影响最大的气溶胶成分.研究发现:2004—2008年,AOD在... 为深入研究长三角地区气溶胶对辐射和降水的影响,本文分析了2004—2014年该区气溶胶光学厚度(aerosol optical depth,AOD)、辐射和降水的时空变化特征,在季节尺度确定了对辐射和降水影响最大的气溶胶成分.研究发现:2004—2008年,AOD在春、夏季明显上升(0.260·(10a)-1、0.066·(10a)-1),辐射在春季明显上升(20.4 W·m-2·(10a)-1))、夏季明显下降(-41.4W·m-2·(10a)-1)),降水在夏季明显上升(4.6mm·(10a)-1)、冬季明显下降(-1.7mm·(10a)-1);2009—2014年秋季AOD明显下降(-0.126·(10a)-1),辐射和降水无明显变化趋势.2004—2014年辐射在春、夏季受云量和气溶胶共同影响,2004—2008年秋、冬季辐射主要受AOD影响,2009—2014年秋、冬季辐射与云量相关性更高.各季节沙尘、海盐气溶胶的AOD小于总AOD的20%,但其对辐射和降水影响更大.春、夏季对辐射影响最大的气溶胶分别是细模态沙尘和细模态海盐;降水在春、夏、冬季均受沙尘气溶胶影响最大. 展开更多
关键词 AOD 辐射 降水
基于在线办公系统的高校图书采访模式探索
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作者 王玉萍 《图书馆建设》 CSSCI 北大核心 2019年第3期117-120,125共5页
对比国内外多种在线办公系统优劣发现,"一起写"在线办公系统综合性能较好。利用"一起写"在线办公系统进行云端共享选书可分为书目数据准备、读者云端选书、图书征订、图书入藏4个阶段。这一举措无需成本投入,图书... 对比国内外多种在线办公系统优劣发现,"一起写"在线办公系统综合性能较好。利用"一起写"在线办公系统进行云端共享选书可分为书目数据准备、读者云端选书、图书征订、图书入藏4个阶段。这一举措无需成本投入,图书采访员只需熟悉使用Excel,就可以轻松实现云端共享选书。"一起写"在线办公系统进行云端共享选书,可以提高图书采访过程的读者参与度、馆藏图书质量、图书借阅率和学科服务质量,减少读者对采访工作的负面印象。 展开更多
关键词 图书采访 在线办公系统 云端 共享选书
一种基于云雾辅助的移动健康监护系统设计 预览
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作者 胡建强 《厦门大学学报:自然科学版》 CAS CSCD 北大核心 2019年第4期608-613,共6页
针对新一代健康监护系统在综合运用传感器网络、云计算和大数据等技术时存在的移动性、网络延迟、慢性疾病预测的准确率局限性问题,设计了一种基于云雾辅助的移动健康监护系统.通过分析基于云雾辅助的移动健康监护系统的层次化结构,解... 针对新一代健康监护系统在综合运用传感器网络、云计算和大数据等技术时存在的移动性、网络延迟、慢性疾病预测的准确率局限性问题,设计了一种基于云雾辅助的移动健康监护系统.通过分析基于云雾辅助的移动健康监护系统的层次化结构,解决了该系统的3项关键技术,包括:采用基于IPv6的网络体系结构以增加移动性,采用基于时间阈值的云雾资源统一调度算法以降低响应延迟,采用基于级联特征降维和特征选择的慢性病变风险分级模型以提高预测的智能性和准确率.对比实验表明,该系统具有更低的响应延迟和更高的慢性病变风险分级准确率,从而有利于心血管病类慢性疾病的早期预警. 展开更多
关键词 IPV6 云雾资源 统一调度算法 健康监护 系统响应
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Impact of the Assimilation Frequency of Radar Data with the ARPS 3DVar and Cloud Analysis System on Forecasts of a Squall Line in Southern China 预览
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作者 Yujie PAN Mingjun WANG 《大气科学进展:英文版》 SCIE CAS CSCD 2019年第2期160-172,共13页
Assimilation configurations have significant impacts on analysis results and subsequent forecasts.A squall line system that occurred on 23 April 2007 over southern China was used to investigate the impacts of the data... Assimilation configurations have significant impacts on analysis results and subsequent forecasts.A squall line system that occurred on 23 April 2007 over southern China was used to investigate the impacts of the data assimilation frequency of radar data on analyses and forecasts.A three-dimensional variational system was used to assimilate radial velocity data,and a cloud analysis system was used for reflectivity assimilation with a 2-h assimilation window covering the initial stage of the squall line.Two operators of radar reflectivity for cloud analyses corresponding to single-and double-moment schemes were used.In this study,we examined the sensitivity of assimilation frequency using 10-,20-,30-,and 60-min assimilation intervals.The results showed that analysis fields were not consistent with model dynamics and microphysics in general;thus,model states,including dynamic and microphysical variables,required approximately 20 min to reach a new balance after data assimilation in all experiments.Moreover,a 20-min data assimilation interval generally produced better forecasts for both single-and double-moment schemes in terms of equitable threat and bias scores.We conclude that a higher data assimilation frequency can produce a more intense cold pool and rear inflow jets but does not necessarily lead to a better forecast. 展开更多
关键词 cloud analysis RADAR DATA ASSIMILATION DATA ASSIMILATION INTERVAL
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云环境下科学工作流的调度算法 预览
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作者 冯复剑 《计算机系统应用》 2019年第7期127-132,共6页
提出一种云环境下科学工作流的调度算法.针对已有的调度算法和松弛时间资源分配策略均未考虑"或"控制结构的不足,给出了关键活动优先级(Critical Activity Priority,CAP)的概念;定义了活动的服务效益比(Service Benefit Ratio... 提出一种云环境下科学工作流的调度算法.针对已有的调度算法和松弛时间资源分配策略均未考虑"或"控制结构的不足,给出了关键活动优先级(Critical Activity Priority,CAP)的概念;定义了活动的服务效益比(Service Benefit Ratio,SBR);提出了活动松弛时间分配策略;并从流程定义和实例运行两个层次,给出了活动截止期限的分配算法.该项研究成果为解决科学工作流调度过程中的时间-成本优化问题提供了更合适的解决方案. 展开更多
关键词 科学工作流 调度 服务效益比
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Satellite-based Observational Study of the Tibetan Plateau Vortex:Features of Deep Convective Cloud Tops 预览
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作者 Yi-Xuan SHOU Feng LU +3 位作者 Hui LIU Peng CUI Shaowen SHOU Jian LIU 《大气科学进展:英文版》 SCIE CAS CSCD 2019年第2期189-205,248共18页
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-2E,Aqua/MODIS and CALIPSO.The objective is to demonstrate:(i)the usef... 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-2E,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. 展开更多
关键词 Tibetan Plateau VORTEX MULTI-SPECTRAL SATELLITE observations short-range/nowcasting weather forecasts cold U/V-shaped cloud top TROPOPAUSE folding
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检索云分享平台 预览
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作者 高峰 傅晓亮 +1 位作者 孙瑞丰 王良猷 《电子测试》 2019年第10期67-69,共3页
针对现有电子化的检索资源数量多、种类丰富及分布离散等特点,为了能更好地利用这些资源,并应用于实际检索,建立了检索云分享平台,本文的主要目的在于介绍检索云分享平台的架构及设计,让读者对"云"在专利检索中的辅助应用有... 针对现有电子化的检索资源数量多、种类丰富及分布离散等特点,为了能更好地利用这些资源,并应用于实际检索,建立了检索云分享平台,本文的主要目的在于介绍检索云分享平台的架构及设计,让读者对"云"在专利检索中的辅助应用有一个更深刻的认识。 展开更多
关键词 检索 分享 平台
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Cloud Service Security Adaptive Target Detection Algorithm Based on Bio-Inspired Performance Evaluation Process Algebra
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作者 ZHAO Guosheng QU Xiaofeng +2 位作者 LIAO Yuting WANG Tiantian ZHANG Jingting 《武汉大学学报:自然科学英文版》 CAS CSCD 2019年第3期185-193,共9页
Combining the principle of antibody concentration with the idea of biological evolution, this paper proposes an adaptive target detection algorithm for cloud service security based on Bio-Inspired Performance Evaluati... Combining the principle of antibody concentration with the idea of biological evolution, this paper proposes an adaptive target detection algorithm for cloud service security based on Bio-Inspired Performance Evaluation Process Algebra(Bio-PEPA). The formal modelling of cloud services is formally modded by Bio-PEPA and the modules are transformed between cloud service internal structures and various components. Then, the security adaptive target detection algorithm of cloud service is divided into two processes, the short-term optimal action selection process which selects the current optimal detective action through the iterative operation of the expected function and the adaptive function, and the long-term detective strategy realized through the updates and eliminations of action planning table. The combination of the two processes reflects the self-adaptability of cloud service system to target detection. The simulating test detects three different kinds of security risks and then analyzes the relationship between the numbers of components with time in the service process. The performance of this method is compared with random detection method and three anomaly detection methods by the cloud service detection experiment. The detection time of this method is 50.1% of three kinds of detection methods and 86.3% of the random detection method. The service success rate is about 15% higher than that of random detection methods. The experimental results show that the algorithm has good time performance and high detection hit rate. 展开更多
关键词 cloud service SECURITY BIO-INSPIRED Performance Evaluation Process ALGEBRA (Bio-PEPA) ADAPTIVE detection biological immunity EVOLUTIONARY mechanism
A Cloud Computing Security Model Based on Noninterference
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作者 LU Congdong QIAN Gang CHEN Tao 《武汉大学学报:自然科学英文版》 CAS CSCD 2019年第3期194-200,共7页
In cloud computing, the risk of data leakage exists between users and virtual machines. Whether it is direct or indirect data leakage, it can be regarded as illegal information flow. Methods such as access control mod... In cloud computing, the risk of data leakage exists between users and virtual machines. Whether it is direct or indirect data leakage, it can be regarded as illegal information flow. Methods such as access control models can control the information flow rather than the covert information flow. Therefore, it needs to use the noninterference models to detect the existence of illegal information flow in cloud computing. Typical noninterference models are not suitable to verificate information flow in cloud computing. When concurrent access actions execute in the cloud architecture, security domains do not affect each other, because there is no information flow between security domains. Based on this, we propose noninterference for cloud architecture in which concurrent access and sequential access coexist. When the sequential actions execute, the information flow between security domains can flow in accordance with established rules. When concurrent access actions execute, there should not be the information flow between security domains. 展开更多
关键词 CLOUD COMPUTING SECURITY information flow SECURITY NONINTERFERENCE NONINTERFERENCE MODELS
Three Tier Fog Networks:Enabling IoT/5G for Latency Sensitive Applications 预览
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作者 Romana Shahzadi Ambreen Niaz +4 位作者 Mudassar Ali Muhammad Naeem Joel J.P.C.Rodrigues Farhan Qamar Syed Muhammad Anwar 《中国通信:英文版》 SCIE CSCD 2019年第3期1-11,共11页
Following the progression in Internet of Things(IoT)and 5G communication networks,the traditional cloud computing model have shifted to fog computing.Fog computing provides mobile computing,network control and storage... Following the progression in Internet of Things(IoT)and 5G communication networks,the traditional cloud computing model have shifted to fog computing.Fog computing provides mobile computing,network control and storage to the network edges to assist latency critical and computation-intensive applications.Moreover,security features are improved in fog paradigm by processing critical data on edge devices instead of data centres outside the control plane of users.However,fog network deployment imposes many challenges including resource allocation,privacy of users,non-availability of programming model and testing software and support for the heterogenous networks.This article highlights these challenges and their potential solutions in detail.This article also discusses threetier fog network architecture,its standardization and benefits in detail.The proposed resource allocation mechanism for three tier fog networks based on swap matching is described.Results show that by practicing the proposed resource allocation mechanism,maximum throughput with reduced latency is achieved. 展开更多
关键词 cloud COMPUTING FOG NETWORKS MATCHING GAMES internet of THINGS
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