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NRT FILES镍钛根管锉预备对弯曲根管应力分布的仿真分析
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作者 蒋谊芳 蔡绮敏 +3 位作者 初政一 秦敏 申煜荣 顾远平 《中国组织工程研究》 CAS 北大核心 2023年第7期1038-1042,共5页
背景:在根管治疗中,镍钛合金器械常因应力超过金属塑性变形的弹性极限或在根管弯曲处重复弯曲导致镍钛合金疲劳断裂。目的:探索新型镍钛锉NRT FILES在作为根管预备材料时对根管内壁存在的应力分布,明确应力集中区域。方法:利用Solidwork... 背景:在根管治疗中,镍钛合金器械常因应力超过金属塑性变形的弹性极限或在根管弯曲处重复弯曲导致镍钛合金疲劳断裂。目的:探索新型镍钛锉NRT FILES在作为根管预备材料时对根管内壁存在的应力分布,明确应力集中区域。方法:利用Solidworks软件对NRT FILES进行三维建模,模拟还原器械在真实口腔环境中存在的状态。建立6组根管简化模型:①弯曲角度30°、弯曲半径5 mm、根尖弯曲;②弯曲角度30°、弯曲半径5 mm、根中弯曲;③弯曲角度30°、弯曲半径2 mm、根尖弯曲;④弯曲角度30°、弯曲半径2 mm、根中弯曲;⑤弯曲角度45°、弯曲半径5 mm、根尖弯曲;⑥弯曲角度45°、弯曲半径2 mm、根尖弯曲。将根管简化模型与根管锉模型进行组配,对根管内壁受力点及应力分布情况进行分析。结果与结论:①-⑥组根管锉最大应力分别为1 185,1 354,1 371,1 678,1 335,2 557 MPa,最大应变分别为0.010 36,0.013 54,0.013 79,0.016 48,0.013 45,0.022 03;根管弯曲部位的不同会影响根管锉所承受的应力大小,因此在根管治疗中,根管锉沿着根管越往下,根管锉与根管接触的半径越大、刚性越差,根管锉所承受的应力越大越容易发生断裂;根管弯曲半径越小,根管锉承受的应力越大;根管弯曲角度越小,根管锉所承受的应力越大。在根尖弯曲部位,根管锉在根管弯曲半径小的弯曲根管需要承受更大的应力,根管锉更容易发生断裂;同理,在根中弯曲部位,根管锉在根管弯曲半径小的弯曲根管亦承受更大的应力,因此要格外注意根管的弯曲程度,以此来选择合适的根管锉进行根管治疗。 展开更多
关键词 弯曲根管 NRT files镍钛锉 根管预备 应力分布 有限元分析
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Automated File Labeling for Heterogeneous Files Organization Using Machine Learning
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作者 Sagheer Abbas Syed Ali Raza +4 位作者 MAKhan Muhammad Adnan Khan Atta-ur-Rahman Kiran Sultan Amir Mosavi 《Computers, Materials & Continua》 SCIE EI 2023年第2期3263-3278,共16页
File labeling techniques have a long history in analyzing the anthological trends in computational linguistics.The situation becomes worse in the case of files downloaded into systems from the Internet.Currently,most ... File labeling techniques have a long history in analyzing the anthological trends in computational linguistics.The situation becomes worse in the case of files downloaded into systems from the Internet.Currently,most users either have to change file names manually or leave a meaningless name of the files,which increases the time to search required files and results in redundancy and duplications of user files.Currently,no significant work is done on automated file labeling during the organization of heterogeneous user files.A few attempts have been made in topic modeling.However,one major drawback of current topic modeling approaches is better results.They rely on specific language types and domain similarity of the data.In this research,machine learning approaches have been employed to analyze and extract the information from heterogeneous corpus.A different file labeling technique has also been used to get the meaningful and`cohesive topic of the files.The results show that the proposed methodology can generate relevant and context-sensitive names for heterogeneous data files and provide additional insight into automated file labeling in operating systems. 展开更多
关键词 Automated file labeling file organization machine learning topic modeling
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Enhanced Best Fit Algorithm for Merging Small Files
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作者 Adnan Ali Nada Masood Mirza Mohamad Khairi Ishak 《Computer Systems Science & Engineering》 SCIE EI 2023年第7期913-928,共16页
In the Big Data era,numerous sources and environments generate massive amounts of data.This enormous amount of data necessitates specialized advanced tools and procedures that effectively evaluate the information and ... In the Big Data era,numerous sources and environments generate massive amounts of data.This enormous amount of data necessitates specialized advanced tools and procedures that effectively evaluate the information and anticipate decisions for future changes.Hadoop is used to process this kind of data.It is known to handle vast volumes of data more efficiently than tiny amounts,which results in inefficiency in the framework.This study proposes a novel solution to the problem by applying the Enhanced Best Fit Merging algorithm(EBFM)that merges files depending on predefined parameters(type and size).Implementing this algorithm will ensure that the maximum amount of the block size and the generated file size will be in the same range.Its primary goal is to dynamically merge files with the stated criteria based on the file type to guarantee the efficacy and efficiency of the established system.This procedure takes place before the files are available for the Hadoop framework.Additionally,the files generated by the system are named with specific keywords to ensure there is no data loss(file overwrite).The proposed approach guarantees the generation of the fewest possible large files,which reduces the input/output memory burden and corresponds to the Hadoop framework’s effectiveness.The findings show that the proposed technique enhances the framework’s performance by approximately 64%while comparing all other potential performance-impairing variables.The proposed approach is implementable in any environment that uses the Hadoop framework,not limited to smart cities,real-time data analysis,etc. 展开更多
关键词 Big data Hadoop MapReduce small file HDFS
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RCache: A Read-Intensive Workload-Aware Page Cache for NVM Filesystem
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作者 TU Yaofeng ZHU Bohong +2 位作者 YANG Hongzhang HAN Yinjun SHU Jiwu 《ZTE Communications》 2023年第1期89-94,共6页
Byte-addressable non-volatile memory(NVM),as a new participant in the storage hierarchy,gives extremely high performance in storage,which forces changes to be made on current filesystem designs.Page cache,once a signi... Byte-addressable non-volatile memory(NVM),as a new participant in the storage hierarchy,gives extremely high performance in storage,which forces changes to be made on current filesystem designs.Page cache,once a significant mechanism filling the performance gap between Dynamic Random Access Memory(DRAM)and block devices,is now a liability that heavily hinders the writing performance of NVM filesystems.Therefore state-of-the-art NVM filesystems leverage the direct access(DAX)technology to bypass the page cache entirely.However,the DRAM still provides higher bandwidth than NVM,which prevents skewed read workloads from benefiting from a higher bandwidth of the DRAM and leads to sub-optimal performance for the system.In this paper,we propose RCache,a readintensive workload-aware page cache for NVM filesystems.Different from traditional caching mechanisms where all reads go through DRAM,RCache uses a tiered page cache design,including assigning DRAM and NVM to hot and cold data separately,and reading data from both sides.To avoid copying data to DRAM in a critical path,RCache migrates data from NVM to DRAM in a background thread.Additionally,RCache manages data in DRAM in a lock-free manner for better latency and scalability.Evaluations on Intel Optane Data Center(DC)Persistent Memory Modules show that,compared with NOVA,RCache achieves 3 times higher bandwidth for read-intensive workloads and introduces little performance loss for write operations. 展开更多
关键词 storage system file system persistent memory
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NIC X-FILE和DENCO Pre-Shaper镍钛器械对模拟弯曲根管成形的影响 被引量:1
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作者 申煜荣 乃仁桐 +4 位作者 赵玲 刘飞刚 尹曹洋 顾远平 陈铁一 《中国组织工程研究》 CAS 北大核心 2024年第3期387-391,共5页
背景:根管预备是根管治疗的关键步骤,近年来随着新型镍钛器械的迅速发展,根管成形能力得到了显著提高,然而不同种类的镍钛系统成形能力亦不同,目前国内外关于R相热处理机用镍钛器械NIC X-FILE和DENCO Pre-Shaper对弯曲根管成形能力的影... 背景:根管预备是根管治疗的关键步骤,近年来随着新型镍钛器械的迅速发展,根管成形能力得到了显著提高,然而不同种类的镍钛系统成形能力亦不同,目前国内外关于R相热处理机用镍钛器械NIC X-FILE和DENCO Pre-Shaper对弯曲根管成形能力的影响鲜见报道。目的:比较NIC X-FILE和DENCO Pre-Shaper机用镍钛锉预备树脂模拟弯曲根管的成形效果。方法:选取树脂模拟弯曲根管50个,随机分为2组(n=25),分别使用NIC X-FILE、DENCO Pre-Shaper镍钛根管锉进行根管预备,记录根管预备时间、采集根管预备前后图像。使用图像处理和分析软件测量各观测点的根管内、外侧壁树脂去除量,运用统计学软件,对比研究两种机用镍钛锉的根管预备时间和中心定位能力。结果与结论:①DENCO Pre-Shaper组平均根管预备时间为(1.58±0.02)min,NIC X-FILE组平均根管预备时间为(2.22±0.03)min,两组间比较差异有显著性意义(P<0.05);②DENCO Pre-Shaper组在距离根尖孔4,5,7,8,9,10 mm处的内侧树脂去除量多于NIC X-FILE组(P<0.05),在距离根尖孔3,5,6,7,8 mm处的外侧树脂去除量少于NIC X-FILE组(P<0.05);③在距离根尖孔2,4,5,6,7,8,9 mm处,NIC X-FILE组的中心定位能力优于DENCO Pre-Shaper组(P<0.05),其中在距离根尖孔4 mm处的中心定位能力最佳;④结果表明,DENCO Pre-Shaper根管锉较NIC X-FILE镍钛根管锉具有较高的机械效率,但其中心定位能力不如NIC X-FILE镍钛根管锉。 展开更多
关键词 NIC X-file DENCO Pre-Shaper 根管预备 镍钛器械 根管预备时间 中心定位能力
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用FileSystemObject对象模型操作文件系统 被引量:2
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作者 刘独玉 罗彬 《重庆电力高等专科学校学报》 2000年第4期30-37,共8页
详细介绍了面向对象编程的操作文件系统的文件对象模型(FileSystemObject,以下简称FSO)的对象、属性和方法,并举例说明了该对象模型的应用。实例证明:用FSO对象模型操作文件系统比传统文件操作语句更简单、更方便、更灵活,功能更强大。
关键词 面向对象编程 操作文件系统 文件对象模型 filesystemObiect Folder对象
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镍钛锉Hyflex CM、Twisted Files和ProTaper Gold预备重度弯曲根管的成形效果
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作者 沈洁 《广西医学》 CAS 2022年第7期712-716,共5页
目的比较Hyflex CM(HCM)、Twisted Files(TF)和ProTaper Gold(PTG)预备重度弯曲根管的成形效果。方法将30颗具有重度弯曲根管的离体磨牙随机分为HCM组、TF组和PTG组,每组10颗,每组采用相应的镍钛锉预备根管。根管预备前后分别用显微CT... 目的比较Hyflex CM(HCM)、Twisted Files(TF)和ProTaper Gold(PTG)预备重度弯曲根管的成形效果。方法将30颗具有重度弯曲根管的离体磨牙随机分为HCM组、TF组和PTG组,每组10颗,每组采用相应的镍钛锉预备根管。根管预备前后分别用显微CT扫描各离体磨牙,获取轴向横截面图片,测量距离根尖孔1 mm、2 mm、3 mm、4 mm、5 mm处和根管最大弯曲处的近、远中根管壁厚度最小值,计算并比较各组的根管偏移量及轴中心率。结果3组离体磨牙距离根尖孔1~5 mm处的根管偏移量、轴中心率差异有统计学意义(均P<0.05)。3组离体磨牙根管最大弯曲处的根管偏移量、轴中心率差异有统计学意义(均P<0.05),其中PTG组的根管偏移量最小、轴中心率最大。结论HCM、TF和PTG均可安全有效地预备重度弯曲根管,其中PTG的中心定位能力更好,更适合重度弯曲根管的预备。 展开更多
关键词 Hyflex CM Twisted files ProTaper Gold 弯曲根管 根管偏移量 轴中心率
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仅用FILES命令并不能同时打开二十多个文件
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作者 孙效玉 王劲波 《计算机时代》 1997年第11期10-11,共2页
1问题的提出 在Novell网上用C语言编制实时微波调度软件时,由于设备、道路、装卸点种类繁多,需统计分析的内容繁多以及工作站之间的信息传递频繁,需处理的文件达30多个,由于系统的实时性,绝大多数文件必须同时打开。但在运行时发现:尽管... 1问题的提出 在Novell网上用C语言编制实时微波调度软件时,由于设备、道路、装卸点种类繁多,需统计分析的内容繁多以及工作站之间的信息传递频繁,需处理的文件达30多个,由于系统的实时性,绝大多数文件必须同时打开。但在运行时发现:尽管对CONFIG.SYS文件中的FILES语句赋值很大,但最多只能同时打开15个文件。开始以为是C语言或网络软件有问题,但不在网络上用其它语言试验亦存在同样问题。 展开更多
关键词 files命令 文件 C语言 程序设计
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新型镍钛器械TwistedFiles的应用 被引量:3
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作者 刘思茗 胡涛 《国际口腔医学杂志》 CAS 2013年第2期185-187,共3页
镍钛器械在根管预备中的使用越来越广泛。Twisted Files(TF)采用了新的制造工艺,具有良好的根管成形作用和更好的循环疲劳抵抗力。本文就TF的牙本质切割效率及维持根管原始形态的能力、循环疲劳抵抗、消毒对TF的影响等方面作一综述。
关键词 TWISTED files 镍钛器械 循环疲劳 器械分离
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Twisted files的研究进展 被引量:3
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作者 刘安东 王艳平 《医学综述》 2012年第13期2061-2064,共4页
Twisted Files(TF)是一种新型的镍钛机动的根管预备器械,它采用扭制的方法制成,且有特殊的外形特点,与其他的镍钛器械相比,其具有更好的抵抗弯曲疲劳机械分离和扭曲机械分离的能力和弹性,且使用简单。因此,在根管成形中TF具有安全和高... Twisted Files(TF)是一种新型的镍钛机动的根管预备器械,它采用扭制的方法制成,且有特殊的外形特点,与其他的镍钛器械相比,其具有更好的抵抗弯曲疲劳机械分离和扭曲机械分离的能力和弹性,且使用简单。因此,在根管成形中TF具有安全和高效两个方面的优势,尤其适应于弯曲根管的预备。在此对TF的组成及外形特点、物理机械性能、使用方法等予以综述。 展开更多
关键词 TWISTED files 根管预备 根管治疗
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e-files-box办公管理系统
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作者 李敏 《哈尔滨商业大学学报(自然科学版)》 CAS 2005年第3期308-310,314,共4页
介绍了办公管理系统在实际应用中的可行性领域.通过对数据库的管理,实现了e files box办公管理系统的开发,着重阐述了系统的主要功能,性能及实现.系统具有友好、简洁、美观的用户界面,良好的安全性,使用户的操作得以充分保障,而且满足... 介绍了办公管理系统在实际应用中的可行性领域.通过对数据库的管理,实现了e files box办公管理系统的开发,着重阐述了系统的主要功能,性能及实现.系统具有友好、简洁、美观的用户界面,良好的安全性,使用户的操作得以充分保障,而且满足数据的一致性和唯一性. 展开更多
关键词 e-file-box SQL SERVER 2000 POWERBUILDER 8.0 办公自动化
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Massive Files Prefetching Model Based on LSTM Neural Network with Cache Transaction Strategy 被引量:2
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作者 Dongjie Zhu Haiwen Du +6 位作者 Yundong Sun Xiaofang Li Rongning Qu Hao Hu Shuangshuang Dong Helen Min Zhou Ning Cao 《Computers, Materials & Continua》 SCIE EI 2020年第5期979-993,共15页
In distributed storage systems,file access efficiency has an important impact on the real-time nature of information forensics.As a popular approach to improve file accessing efficiency,prefetching model can fetches d... In distributed storage systems,file access efficiency has an important impact on the real-time nature of information forensics.As a popular approach to improve file accessing efficiency,prefetching model can fetches data before it is needed according to the file access pattern,which can reduce the I/O waiting time and increase the system concurrency.However,prefetching model needs to mine the degree of association between files to ensure the accuracy of prefetching.In the massive small file situation,the sheer volume of files poses a challenge to the efficiency and accuracy of relevance mining.In this paper,we propose a massive files prefetching model based on LSTM neural network with cache transaction strategy to improve file access efficiency.Firstly,we propose a file clustering algorithm based on temporal locality and spatial locality to reduce the computational complexity.Secondly,we propose a definition of cache transaction according to files occurrence in cache instead of time-offset distance based methods to extract file block feature accurately.Lastly,we innovatively propose a file access prediction algorithm based on LSTM neural network which predict the file that have high possibility to be accessed.Experiments show that compared with the traditional LRU and the plain grouping methods,the proposed model notably increase the cache hit rate and effectively reduces the I/O wait time. 展开更多
关键词 Massive files prefetching model cache transaction distributed storage systems LSTM neural network
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An Error-Correcting Code-Based Robust Watermarking Scheme for Stereolithographic Files 被引量:1
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作者 Zhuorong Li Huawei Tian +2 位作者 Yanhui Xiao Yunqi Tang Anhong Wang 《Computer Systems Science & Engineering》 SCIE EI 2021年第5期247-263,共17页
Stereolithographic(STL)files have been extensively used in rapid prototyping industries as well as many other fields as watermarking algorithms to secure intellectual property and protect three-dimensional models from... Stereolithographic(STL)files have been extensively used in rapid prototyping industries as well as many other fields as watermarking algorithms to secure intellectual property and protect three-dimensional models from theft.However,to the best of our knowledge,few studies have looked at how watermarking can resist attacks that involve vertex-reordering.Here,we present a lossless and robust watermarking scheme for STL files to protect against vertexreordering attacks.Specifically,we designed a novel error-correcting code(ECC)that can correct the error of any one-bit in a bitstream by inserting several check digits.In addition,ECC is designed to make use of redundant information according to the characteristics of STL files,which introduces further robustness for defense against attacks.No modifications are made to the geometric information of the three-dimensional model,which respects the requirements of a highprecision model.The experimental results show that the proposed watermarking scheme can survive numerous kinds of attack,including rotation,scaling and translation(RST),facet reordering,and vertex-reordering attacks. 展开更多
关键词 Three-dimensional watermarking stereolithographic file robust watermarking error-correcting code
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Always-optimally-coordinated candidate selection algorithm for peer-to-peer files sharing system in mobile self-organized networks 被引量:1
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作者 李曦 Ji Hong +1 位作者 Zheng Ruiming Li Ting 《High Technology Letters》 EI CAS 2009年第3期281-287,共7页
In order to improve the performance of peer-to-peer files sharing system under mobile distributed en- vironments, a novel always-optimally-coordinated (AOC) criterion and corresponding candidate selection algorithm ... In order to improve the performance of peer-to-peer files sharing system under mobile distributed en- vironments, a novel always-optimally-coordinated (AOC) criterion and corresponding candidate selection algorithm are proposed in this paper. Compared with the traditional min-hops criterion, the new approach introduces a fuzzy knowledge combination theory to investigate several important factors that influence files transfer success rate and efficiency. Whereas the min-hops based protocols only ask the nearest candidate peer for desired files, the selection algorithm based on AOC comprehensively considers users' preferences and network requirements with flexible balancing rules. Furthermore, its advantage also expresses in the independence of specified resource discovering protocols, allowing for scalability. The simulation results show that when using the AOC based peer selection algorithm, system performance is much better than the rain-hops scheme, with files successful transfer rate improved more than 50% and transfer time re- duced at least 20%. 展开更多
关键词 peer-to-peer files sharing system mobile self-organized network candidate selection fuzzy knowledge combination always-optimally-coordinated (AOC)
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基于FileSystem API的HDFS文件存取和副本选择优化研究
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作者 贾会玲 吴晟 +3 位作者 李英娜 李萌萌 杨玺 李川 《化工自动化及仪表》 CAS 2016年第6期623-627,共5页
在对HDFS进行分析和研究的基础上,在HDFS文件分布式系统中应用File System API进行文件存储和访问,并通过改进的蚁群算法对副本选择进行优化。HDFS API能够有效完成海量数据的存储和管理,提高海量数据存储的效率。通过改进的蚁群算法提... 在对HDFS进行分析和研究的基础上,在HDFS文件分布式系统中应用File System API进行文件存储和访问,并通过改进的蚁群算法对副本选择进行优化。HDFS API能够有效完成海量数据的存储和管理,提高海量数据存储的效率。通过改进的蚁群算法提升了文件读取时副本选择的效率,进一步提高了系统效率并使负载均衡。 展开更多
关键词 HDFS filesystem API 改进的蚁群算法 副本选择
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A Preliminary Study on the Management Strategy of University Personnel Files based on Artificial Intelligence Technology 被引量:2
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作者 Litao Cui 《Journal of Electronic Research and Application》 2021年第2期1-4,共4页
In order to improve the management strategy for personnel files in colleges and universities,simplify the complex process of file management,and improve file management security and content preservation of the files.T... In order to improve the management strategy for personnel files in colleges and universities,simplify the complex process of file management,and improve file management security and content preservation of the files.This paper elaborates on the application of Artificial Intelligence(AI)technology in university personnel file management through theoretical analysis based on the understanding of Al technology. 展开更多
关键词 AI technology Personnel files Management strategy
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A novel clustering and supervising users' profiles method
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作者 ZhuMingfu ZhangHongbin SongFangyun 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2005年第2期456-459,共4页
To better understand different users' accessing intentions, a novel clustering and supervising method based on accessing path is presented. This method divides users' interest space to express the distribution... To better understand different users' accessing intentions, a novel clustering and supervising method based on accessing path is presented. This method divides users' interest space to express the distribution of users' interests, and directly to instruct the constructing process of web pages indexing for advanced performance. 展开更多
关键词 cluster tree group/CT tree SESSION log data files
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New Synchronization Algorithm Based on Delta Synchronization for Compressed Files in the Mobile Cloud Environment
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作者 Rizik M. H. Al-Sayyed Feras F. Namous +2 位作者 AlMonther H. Alkhalafat Bashar Al-Shboul Samar Al-Saqqa 《International Journal of Communications, Network and System Sciences》 2017年第4期59-74,共16页
The fast growing market of mobile device adoption and cloud computing has led to exploitation of mobile devices utilizing cloud services. One major chal-lenge facing the usage of mobile devices in the cloud environmen... The fast growing market of mobile device adoption and cloud computing has led to exploitation of mobile devices utilizing cloud services. One major chal-lenge facing the usage of mobile devices in the cloud environment is mobile synchronization to the cloud, e.g., synchronizing contacts, text messages, imag-es, and videos. Owing to the expected high volume of traffic and high time complexity required for synchronization, an appropriate synchronization algo-rithm needs to be developed. Delta synchronization is one method of synchro-nizing compressed files that requires uploading the whole file, even when no changes were made or if it was only partially changed. In the present study, we proposed an algorithm, based on Delta synchronization, to solve the problem of synchronizing compressed files under various forms of modification (e.g., not modified, partially modified, or completely modified). To measure the effi-ciency of our proposed algorithm, we compared it to the Dropbox application algorithm. The results demonstrated that our algorithm outperformed the regular Dropbox synchronization mechanism by reducing the synchronization time, cost, and traffic load between clients and the cloud service provider. 展开更多
关键词 MOBILE CLOUD Computing DELTA SYNCHRONIZATION Compressed files DROPBOX
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Peer selecting model based on FCM for wireless distributed P2P files sharing systems
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作者 李曦 纪红 郑瑞明 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2010年第5期593-599,共7页
IIn order to improve the performance of wireless distributed peer-to-peer(P2P)files sharing systems,a general system architecture and a novel peer selecting model based on fuzzy cognitive maps(FCM)are proposed in this... IIn order to improve the performance of wireless distributed peer-to-peer(P2P)files sharing systems,a general system architecture and a novel peer selecting model based on fuzzy cognitive maps(FCM)are proposed in this paper.The new model provides an effective approach on choosing an optimal peer from several resource discovering results for the best file transfer.Compared with the traditional min-hops scheme that uses hops as the only selecting criterion,the proposed model uses FCM to investigate the complex relationships among various relative factors in wireless environments and gives an overall evaluation score on the candidate.It also has strong scalability for being independent of specified P2P resource discovering protocols.Furthermore,a complete implementation is explained in concrete modules.The simulation results show that the proposed model is effective and feasible compared with min-hops scheme,with the success transfer rate increased by at least 20% and transfer time improved as high as 34%. 展开更多
关键词 wireless P2P files sharing systems peer selecting model fuzzy cognitive maps
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Shaping ability of thermomechanically treated files in simulated S-shaped root canals
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作者 Nessrin A. Taha Ghada A. Maghaireh +2 位作者 Dyana El Sadek Rafat Bagheri Mohammad Al-Omari 《Open Journal of Stomatology》 2013年第7期386-391,共6页
Aim: the aim of this study was to investigate the shaping ability of thermomechanically treated files manufactured by twisting(Twisted files)and compare it to conventional rotary system (K3, Sybron Endo, Orange, CA) i... Aim: the aim of this study was to investigate the shaping ability of thermomechanically treated files manufactured by twisting(Twisted files)and compare it to conventional rotary system (K3, Sybron Endo, Orange, CA) in S-shaped canals, including formation of ledges, zipping, elbow, outer widening, danger zone, perforation and file deformation. Materials & Methods: Forty S-Shaped canals in resin blocks were randomly divided into 2 groups of 20 each. Pre-instrumentation images of the canals were taken via a digital camera and superimposed on images taken after preparation with TF and K3 systems to apical size of 25/06 and 30/06. Canal aberrations were measured from the superimposed image at five levels using AutoCAD system. Fisher exact test and Mann Whitney test were used for analysis of the data. Results: the incidence of zipping, elbow and apical transportation was significantly lower in the TF group (P = 0.04). Generally the incidence of aberration increased when the apical size increased to 30/0.06 regardless of the file system. Significant file deformation was evident in the TF after single use (P ? 0.001). Conclusion: Under the conditions of this study, TF manufactured by new technique performed better than K3 systems when used up to size 25/06 in simulated S-shaped canals. Clinical significance: The flexibility of thermomechanically treated files is beneficial in canals with multiple curvatures;however, attention should be paid to the instrument taper and final apical size of the preparation. 展开更多
关键词 Keywords: S-Shaped CANAL TWISTED files K3 CANAL ABERRATION
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