关键词： Mobile cloud computing   computational offloading   approximation algorithms   on-line learning  

摘要： With mobile devices increasingly able to connect to cloud servers from anywhere, resource-constrained devices can potentially perform offloading of computational tasks to either save local resource usage or improve performance. It is of interest to find optimal assignments of tasks to local and remote devices that can take into account the application- specific profile, availability of computational resources, and link connectivity, and find a balance between energy consumption costs of mobile devices and latency for delay-sensitive applications. We formulate an NP-hard problem to minimize the application latency while meeting prescribed resource utilization constraints. Different from most of existing works that either rely on the integer programming solver, or on heuristics that offer no theoretical performance guarantees, we propose Hermes, a novel fully polynomial time approximation scheme (FPTAS). We identify for a subset of problem instances, where the application task graphs can be described as serial trees, Hermes provides a solution with latency no more than (1 + epsilon) times of the minimum while incurring complexity that is polynomial in problem size and 1/epsilon. We further propose an online algorithm to learn the unknown dynamic environment and guarantee that the performance gap compared to the optimal strategy is bounded by a logarithmic function with time. Evaluation is done by using real data set collected from several benchmarks, and is shown that Hermes improves the latency by 16 percent compared to a previously published heuristic and increases CPU computing time by only 0: 4 percent of overall latency.

关键词： 音乐课堂   智慧教育   互联网时代   信息技术   信息化进程   移动计算   教育改革   生产力  

摘要： 随着生产力的不断发展,一些新的技术不断涌现,如云计算、大数据、物联网以及移动计算等。这些新的信息技术对社会各方面的影响日益强烈,一步步推动着社会的信息化进程。信息技术已经与人们生活的方方面面建立起了密切的联系,当然,信息技术也已经和教育建立了密切的联系。翻转课堂就是信息技术和教育相结合的产物,翻转课堂的出现极大地推动了当代教育改革的步伐。

关键词： chalcone   2 '-hydroxy-3,4,5-trimethoxy-chalcone   GIAO-NMR   scaling factor   NMR spectroscopy  

摘要： In this paper we investigated the ability of the GIAO-mPW1PW91/6-31G(d)//mPW1PW91/6-31G(d) level of theory to predict the C-13 nuclear magnetic resonance (NMR) chemical shifts of the 2'-hydroxy3,4,5-trimethoxy-chalcone molecule. Two different approaches were used. First: the absolute shieldings sigma for all carbon atoms in each geometrically optimized conformers of the 2'-hydroxy3,4,5-trimethoxy-chalcone molecule were calculated at the GIAO-mPW1PW91/6-31G(d)//mPW1PW91/6-31G(d) level of theory. This approach is further used to generate weighted average values for each atom considering the previously obtained conformational distribution. Second: only the s for the lowest energetic conformer will be taken to account. The robustness of the method was evaluated for two other chalcones: (E)-1-(4-hydroxy-3-methoxyphenyl)-3-(3,5-di-tert-butyl-4-hydroxyphenyl) prop-2-en-1-one and (E)-1-(4-aminophenyl)-3-(3,4-dimethoxyphenyl) prop-2-en1-one, corroborating the ability of the method in chemical shift prevision. Although, both approaches were able to reproduce the chemical shifts of the 2'-hydroxy-3,4,5-trimethoxy-chalcone, significant differences in the calculated values for C-4 and methoxy carbons were observed. The best results were obtained using the second approach (II).

关键词： 曼哈顿距离   移动计算   概率Skyline查询   不确定数据  

摘要： 在众多应用中,由于受到测量仪器精度、更新延迟、网络带宽等限制,不同形式的数据不确定性广泛存在。目前,不确定数据中的信息查询受到数据库研究领域学者的关注,并且为不确定数据寻找高效的分析方法也成为了一个热门课题。本文针对基于曼哈顿距离的不确定移动对象概率Skyline查询问题,提出一个基于曼哈顿距离的概率Skyline模型用于求解不确定移动对象在某时刻是Skyline的概率,并得到一个p-t-Skyline结果集,此集合包含所有在t时刻Skyline概率至少是p的移动对象。在实际应用中,计算大量不确定移动对象的Skyline概率过程繁琐,代价高昂。为提高概率Skyline查询过程的计算效率,本文提出包含"采样-限定-修剪-精炼"4个步骤的解决方案。同时,为进一步减少Skyline运算开销,本文使用一个多维索引结构VCI树以加快数据检索的效率。实验结果表明该解决方案在不同数据规模以及维度的数据集上均具有较高的效率。

关键词： 临床药学   移动医疗   移动计算技术   无线网络   药学监护  

摘要： 目的:建设移动药师工作系统平台,为临床药师工作提供信息化支撑。方法:采用Web Service+IOS应用程序相结合的方式,根据临床药师的业务流程与特点,研发出移动药师工作站系统,并在临床应用。结果:通过院内无线网络,临床药师可利用移动设备,完成药学查房、药学监护、药学会诊、患者教育及医嘱审核、干预等临床药学服务。结论:利用移动计算技术可以打破电子病历信息到患者床前的瓶颈,从而帮助临床药师优化并且实时的获取和记录医疗信息,提高临床药师的工作效率与质量。

关键词： Model operator approach   QED corrections   Alkali metals   Highly charged molecular ions  

摘要： The quantum electrodynamics (QED) corrections to the alkali metal ionization potentials and to the ground-state energy of the U92+ - U91+ one-electron quasi-molecule are evaluated with the use of the model operator approach. The QED contributions to the ionization energies in the alkali metals are obtained both by averaging the model operator with the valence electron wave functions and by incorporating the QED operator into the Dirac-Coulomb-Breit Hamiltonian. The two-center calculations of the vacuum-polarization and self-energy contributions to the Lamb shift in the one-electron quasi-molecule are performed for the different values of the internuclear distances (from the chemical distances up to the critical ones), the more simplified evaluation in the monopole approximation is also considered. The results of the calculations are compared with the theoretical predictions obtained previously in the framework of the ab initio approaches. (C) 2017 Elsevier B.V. All rights reserved.

关键词： 互联网时代   王新   智库   组织   社群   合作机制   移动计算   增长态势  

摘要： 王新涛是大数据专家,近日,记者就大数据方面的相关问题及其由此产生的合作机制等采访了他。记者：您能否介绍一下＂首席数据官＂这个概念？王新涛：在移动计算、物联网、云计算等一系列新兴技术的支持下,数据量呈现前所未有的增长态势。大数据的真正价值是通过数据分析,一是为决策提供深度支持,二是在具体业务场景中提高工作效率,

关键词： Internet of people   Cyber-physical convergence   Pervasive systems   People-centric computing and networking   Data-centric networking   Cognitive heuristics   Social networks   Privacy   Trust models  

摘要： Cyber-Physical convergence, the fast expansion of the Internet at its edge, and tighter interactions between human users and their personal mobile devices push toward an Internet where the human user becomes more central than ever, and where their personal devices become their proxies in the cyber world, in addition to acting as a fundamental tool to sense the physical world. The current Internet paradigm, which is infrastructurecentric, is not the right one to cope with such emerging scenario with a wider range of applications. This calls for a radically new Internet paradigm, that we name the Internet of People (IoP), where the humans and their personal devices are not seen merely as end users of applications, but become active elements of the Internet. Note that IoP is not a replacement of the current Internet infrastructure, but it exploits legacy Internet services as (reliable) primitives to achieve end-to-end connectivity on a global-scale. In this visionary paper, we first discuss the key features of the IoP paradigm along with the underlying research issues and challenges. Then we present emerging networking and computing paradigms that are anticipating IoP. (C) 2017 Published by Elsevier B.V.

关键词： 位置隐私   连续查询   道路网络   基于位置服务   移动计算  

摘要： 连续查询作为基于位置服务中常见的服务类型之一,为人们的生活和工作带来了巨大的便利.最近几年,针对位置服务中的隐私保护引起了学术界研究者的广泛关注.然而,现有在道路网络上的位置隐私保护工作大多针对快照查询提供隐私保护.如果直接将这些算法应用于连续查询,由于连续查询中位置频繁更新,将同时产生连续查询隐私泄露和精确位置的泄露.由于网络拓扑的存在,移动用户的运动在一段时间内具有时空相似的特点.利用连续查询用户的时空相似性,提出了一种在道路网络上基于时空相似性的连续查询隐私保护算法.通过采取分组策略构造匿名集和K-共享机制,提出了一种启发式宽度优先用户搜索算法HBFS来构造匿名用户集,并提出了一种连续时刻内匿名路段集生成算法CSGA生成匿名路段集合,可以同时防止连续查询攻击和位置依赖攻击.最后,采用4个评价标准对算法进行了一系列实验,验证了算法的有效性.

关键词： ARM   架构   移动计算   能耗比   GPU  

摘要： ARM在移动计算领域的地位无可比拟，但这并不意味着ARM可以停滞不前。技术的发展永无止境，ARM从几年前开始就保持了每年推出一个全新架构的节奏。去年，ARM推出了极端注重能耗比的Cortex-A73核心和全新的Ma-G71 GPU。