关键词： fecundability   fertile window   fertility   time to pregnancy   preconception   cohort studies  

摘要： STUDY QUESTION: To what extent does the use of mobile computing apps to track the menstrual cycle and the fertile window influence fecundability among women trying to conceive? SUMMARY ANSWER: After adjusting for potential confounders, use of any of several different apps was associated with increased fecundability ranging from 12% to 20% per cycle of attempt. WHAT IS KNOWN ALREADY: Many women are using mobile computing apps to track their menstrual cycle and the fertile window, including while trying to conceive. STUDY DESIGN, SIZE, DURATION: The Pregnancy Study Online (PRESTO) is a North American prospective intemet-based cohort of women who are aged 21-45 years, trying to conceive and not using contraception or fertility treatment at baseline. PARTICIPANTS/MATERIALS, SETTING, METHODS: We restricted the analysis to 8363 women trying to conceive for no more than 6 months at baseline;the women were recruited from June 2013 through May 2019. Women completed questionnaires at baseline and every 2 months for up to I year. The main outcome was fecundability, i.e. the per-cycle probability of conception, which we assessed using self-reported data on time to pregnancy (confirmed by positive home pregnancy test) in menstrual cycles. On the baseline and follow-up questionnaires, women reported whether they used mobile computing apps to track their menstrual cycles ('cycle apps') and, if so, which one(s). We estimated fecundability ratios (FRs) for the use of cycle apps, adjusted for female age, race/ethnicity, prior pregnancy, BMI, income, current smoking, education, partner education, caffeine intake, use of hormonal contraceptives as the last method of contraception, hours of sleep per night, cycle regularity, use of prenatal supplements, marital status, intercourse frequency and history of subfertility. We also examined the impact of concurrent use of fertility indicators: basal body temperature, cervical fluid, cervix position and/or urine LH. MAIN RESULTS AND THE ROLE

关键词： 目标追踪   边缘计算   资源分配   深度学习   移动计算  

摘要： 目标追踪算法虽已在诸多领域得到广泛应用,然而由于实时性和功耗问题,使得基于深度学习模型的算法难以在移动终端设备上部署应用.结合边缘计算技术,从应用部署优化的角度,对目标追踪算法在移动设备上的部署策略进行研究.通过对目标追踪应用特点、移动设备特性以及边缘云网络架构的分析,提出一种面向边缘计算的目标追踪应用部署策略.通过任务分割策略,将目标追踪应用的计算任务合理卸载至边缘云,并利用信息融合策略对计算结果进行分析融合;此外,利用运动检测,进一步降低终端节点的计算压力和功耗.通过对不同部署策略进行对比实验,结果表明:相比计算任务本地计算,该部署策略明显降低了任务响应时间;相比完全卸载至边缘云,该部署策略降低了相同计算任务的处理时间.

关键词： Task offloading   Energy efficient   ADMM   Privacy preserving   Edge computing   Internet of things  

摘要： The pervasive application of Internet of Things (IoT) has pushed the proliferation of edge computing. There exists potential in edge computing to satisfy the concerns of task delay, network bandwidth, battery endurance and data privacy. The superiority of edge computing is endorsed by the deployment of edge nodes to the device user's proximity. Within partial capabilities of the cloud server, edge nodes efficaciously alleviate the burden on core network. Considering a mission critical system, enduring battery life is even more accentuated over task latency to maintain the device on operation. So in this paper, we put forward an energy efficient task offloading problem subject to the overall task delay based on Alternating Direction Method of Multipliers (ADMM) in a three-tier MEC network, equipped with both edge nodes and the cloud. The offloading choice is the approximate convergence with demanded precision concluded by persistent ADMM iterations. We also address the privacy disclosure concerns in the data transmission among IoT devices and apply differential privacy to the intricate optimization problem. More specifically, we associate privacy-preserving method with the exhaustive task offloading processes and iteration procedures. At last, simulations and experiments demonstrate the performance and convergence of our proposed algorithm. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Divided differences   Matrix exponential   Scaling and squaring method   Quantum Monte Carlo algorithms   Off-diagonal series expansion  

摘要： We introduce a method for calculating the divided differences of the exponential function by means of addition and removal of items from the input list to the function. Our technique exploits a new identity related to divided differences recently derived by Zivcovich (2019). We show that upon adding an item to or removing an item from the input list of an already evaluated exponential, the re-evaluation of the divided differences can be done with only O(sn) floating point operations and O(sn) bytes of memory, where [z(0), ..., z(n)] are the inputs and s proportional to max(i,j) vertical bar z(i) - z(j)vertical bar. We demonstrate our algorithm's ability to deal with input lists that are orders-of-magnitude longer than the maximal capacities of the current state-of-the-art. We discuss in detail one practical application of our method: the efficient calculation of weights in the off-diagonal series expansion quantum Monte Carlo algorithm. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Tellurium   Solvents   Basis sets   Chemical calculations   Mathematical methods  

摘要： An accurate quantum chemical modeling of Te-125 NMR spectra is of great importance in the NMR structural assignment for real-life tellurium compounds, which represent a growing interest in organic and inorganic chemistry nowadays. This work reports a computationally modest combined approach based on the density functional theory only, which provides an excellent accuracy against the experiment and can be effectively applied for the routine large-scale calculations of tellurium chemical shifts. The role of solvent, vibrational, and relativistic corrections has been thoroughly investigated. Special attention was paid to the effect of taking into account the scalar relativistic effects during the geometry optimizations on the calculated tellurium chemical shifts.

关键词： Internet of Things   Resource management   Informatics   Mobile computing   Wireless sensor networks   Energy consumption   Minimization  

摘要： INTERNET of Thing (IoT) technology has attracted intensive interest in the automotive industry to meet the new demands in the market while continuing to achieve their conservative goals [item 1) in the Appendix]. As for Industrial Internet of Things (IIoT), randomly moving wireless nodes are often carried by humans and communicate with each other when they are in close proximity. The interaction between nodes shows strong regularity or sociality, i.e., a wireless node always communicates with several social-closed or distance-closed nodes. This special section collects the latest ideas and research on the social and cognitive mobile computing in IIoT. Particularly, 15 original articles are accepted and included in the collection on the following pages. The topics of these articles are mainly concerned with social and cognitive mobility modeling, routing protocol, resource allocation, and so forth. We believe that these articles will play a role in inspiring our readers. Summaries of accepted articles are provided.

关键词： Internet of things   k-nearest neighbor search   Location-based services   Mobile computing   Spatial air index  

摘要： In the Internet of thing (IoT), with the geographic location of geospatial sensor data and the global positioning systems, location-based services (LBSs) can provide powerful location-aware IoT applications for mobile clients according to their current locations. For LBSs, ak-nearest neighbor (kNN) search can provide a mobile client with geospatial sensor data ofk-nearest spatial points of interest (POIs) according to its current location. In this paper, we propose a spatial air index with neighbor information to organize IoT geospatial sensor data for processing kNN searches in the wireless broadcast systems. Since the answered POIs may be neighbors of each other, we add neighbor information to the index structure, which is interleaved with geospatial sensor data, to speed up the query processing. To avoid unnecessary examination of geospatial sensor data from the wireless channel, the proposed method provides the centroid of geospatial data and the corresponding longest distance between the centroid and geospatial data in the region. With this information, the query processing of a kNN search can quickly determine whether to skip examining this region, saving energy consumption of the mobile device. Performance evaluations have verified that the proposed method outperforms the distributed spatial index.

关键词： 移动计算   AI   GPU   ARM   CPU架构   应用场景   核心架构   性能优势  

摘要： 在MC此前的文章中,我们介绍了ARM新推出的Cortex-A78和Cortex-X1架构的相关内容。在CPU架构之外,ARM今年也更新了GPU和AI加速核心架构,也就是本文要介绍的ARM Mali-G78和Ethos-N78。这两个全新的高性能移动计算核心带来了更强大的性能和更宽泛的应用场景。那么,它们都有哪些值得注意的技术特点和性能优势呢?

关键词： Software systems   Software evolution   Software architecture   Mobile computing   Bigraph specification   Structural characteristics   Evolution analysis  

摘要： Software system evolution is an active and important research topic in software engineering. In guiding software system evolution, software architecture plays a critical role. In the traditional software architecture, only the link information of components is considered, while the place information of components is usually neglected. However, due to the emerging mobile computing, pervasive computing, and intelligent computing, the place information is as important as the link information in the software architecture. Especially in mobile computing environments, the place changes often lead to changes in software configuration and functionality. In this paper, we study the Bigraph specification of software architecture and use it to describe both link and place information in detail. Based on Bigraph specification, we investigate the structural characteristics in the software architecture, and design checking algorithms for the component's link exceptions and place exceptions. Furthermore, we address the well-evolved software architecture from a new perspective, which includes three basic evolution operation rules and their well-evolved conditions. We discuss the overall software architecture evolution through strong and weak bi-simulation in terms of software functionality. Finally, two case studies about software system in the evolution operation are presented, which illustrate the effectiveness of our approach. (C) 2020 Elsevier B.V. All rights reserved.

关键词： 无源射频技术   步态识别   用户行为感知   移动计算   无线感知   物联网   身份认证   生物特征识别  

摘要： 步态识别作为一种新兴的生物特征识别技术,具有距离远、难伪造的优点,在智能监控等领域中具有广泛的应用前景。现有的步态识别方法存在着算法计算复杂、用户参与度高、设备开销较大等问题。针对这些问题,文中提出了一种基于无源射频技术的用户步态识别方法。该方法使用了门禁系统中已经广泛部署的无源射频标签,通过标签相位数据计算用户行走动态速度,利用多标签信号互补特性进行信号补偿,提取用户步态频率响应特征。实验结果显示,该方法的用户识别准确率高达91.87%,特征提取及比对的时延仅有0.129 s。在训练数据极少、用户参与度低的情况下,实现了高效率、较准确的用户步态识别及认证。