Wearable skin-like optoelectronic systems with suppression of motion artifacts for cuff-less continuous blood pressure monitor

According to the statistics of the World Health Organization, an estimated 17.9 million people die from cardiovascular diseases each year, representing 31% of all global deaths. Continuous non-invasive arterial pressure (CNAP) is essential for the management of cardiovascular diseases. However, it is difficult to achieve long-term CNAP monitoring with the daily use of current devices due to irritation of the skin as well as the lack of motion artifacts suppression. Here, we report a high-performance skin-like optoelectronic system integrated with ultra-thin flexible circuits to monitor CNAP. We introduce a theoretical model via the virtual work principle for predicting the precise blood pressure and suppressing motion artifacts, and propose optical difference in the frequency domain for stable optical measurements in terms of skin-like devices. We compare the results with the blood pressure acquired by invasive (intra-arterial) blood pressure monitoring for >1500 min in total on 44 subjects in an intensive care unit. The maximum absolute errors of diastolic and systolic blood pressure were ±7/±10 mm Hg, respectively, in immobilized, and ±10/±14 mm Hg, respectively, in walking scenarios. These strategies provide advanced blood pressure monitoring techniques, which would directly address an unmet clinical need or daily use for a highly vulnerable population.     

Preparing the Next Generation of Educational Measurement Specialists: A Call for Programs With an Integrated Scope and Sequence

The field of educational measurement has evolved considerably since the first doctoral programs were established. In response, programs have typically tacked on courses that address newly developed theories, methods, tools, and techniques. As our review of current programs evidences, this approach produces artificial distinctions among topics and techniques that are in fact a tightly coupled whole. This position paper advocates a redesign of the scope and sequence for doctoral programs focused on the preparation of the next generations of educational measurement specialists; a redesign that reflects the full life‐cycle of instrument development and use.     

用测量不确定度GUM表示测量误差的方法

测量不确定度GUM的评定与表示是一个较新的概念,其应用具有广泛性和实用性。用测量不确定度来表示测量误差的方法,是科技交流和国际贸易的迫切要求。它使各国进行的测量及其所得结果可以进行相互比对,以取得相互间的承认或共识,从而受到了国际组织和各国计量部门的高度重视。     

The Path of Least Resistance: Using Available Tools to Support the E-Resources Lifecycle

On the surface, it might appear that libraries with different collections, staffing levels, and budgets would have to make use of different tools to address their e-resource management needs. However, in their review of electronic resources lifecycle work at North Carolina State University and Georgia Perimeter College, Tessa Minchew and Sofia Slutskaya discovered that this is not always the case. The presenters reviewed the electronic resources lifecycle and three distinct types of tools (content management systems/wikis, Microsoft Access, and Trello) that are being used in different ways to address different lifecycle-related tasks at each of their institutions.     

基于网络问答社区的话题识别与分析——以知乎“老年人”话题为例

[目的/意义]针对目前基于网络的话题识别与分析方法的局限性,提出针对网络问答社区的话题识别与分析方法,为此类网站的话题识别与分析提供参考。[方法/过程]以改进的中文分词技术为基础,构建网络问答社区的话题识别指标,通过线性加权方式计算权重,结合关键词提取方法确定话题关键词,对话题关注焦点进行提取,对分布情况进行测度。依据所提出的改进方法,以知乎网站为数据来源,从话题关键词、关键词分布以及热点子话题3个角度对"老年人"话题焦点进行识别与分析。[结果/结论]研究表明,该方法具有科学性和可行性,不仅拓展了社会问题的分析数据源,也为"积极开展应对人口老龄化行动"提供了决策依据。     

Helical angle measurement of worm by a coordinate measuring machine and its uncertainty evaluation

The purpose of the study concerns the measurement of worm’s helical angle by a coordinate measurement machine in the ambient industrial environment. The novel measurement method and sampling strategy were described firstly. This method used the coordinate measurement machine to measure both of the worm gear’s left and right surfaces. The worm surface was reconstructed based on the measured data of all the sampling points. Then a middle cylinder was established to truncate the fitted worm surfaces, and the truncated spiral lines were straightened to calculate the helical angle. The measurement uncertainty of worm’s helical angle was evaluated by taking the difference of calculated helical angles along the truncated spiral lines on both the left and right side surfaces of the worm. Twenty-four measurement experiments show that the maximum measurement error of the proposed method is 0.105, and the measurement error ratios are all less than 3.5?. The result means that the measurement method can realize the precision measurement of worm’s helical angle and can be employed in the generally industrial application.     

一种凸轮升程误差的非接触式测量新方法

分析现有几种凸轮升程误差测量方法的优、缺点后，提出一种基于图像处理的凸轮升程误差的非接触式测量新方法．理论分析和比较实验结果表明，该测量方法简便易行，测量精度较高，具有一定的应用价值．     

Assessment of three-dimensional joint kinematics of the upper limb during simulated swimming using wearable inertial-magnetic measurement units

The analysis of the joint kinematics during swimming plays a fundamental role both in sports conditioning and in clinical contexts. Contrary to the traditional video analysis, wearable inertial-magnetic measurements units (IMMUs) allow to analyse both the underwater and aerial phases of the swimming stroke over the whole length of the swimming pool. Furthermore, the rapid calibration and short data processing required by IMMUs provide coaches and athletes with an immediate feedback on swimming kinematics during training. This study aimed to develop a protocol to assess the three-dimensional kinematics of the upper limbs during swimming using IMMUs. Kinematics were evaluated during simulated dry-land swimming trials performed in the laboratory by eight swimmers. A stereo-photogrammetric system was used as the gold standard. The results showed high coefficient of multiple correlation (CMC) values, with median (first–third quartile) of 0.97 (0.93–0.95) and 0.99 (0.97–0.99) for simulated front-crawl and breaststroke, respectively. Furthermore, the joint angles were estimated with an accuracy increasing from distal to proximal joints, with wrist indices showing median CMC values always higher than 0.90. The present findings represent an important step towards the practical use of technology based on IMMUs for the kinematic analysis of swimming in applied contexts.     

Accelerometer data requirements for reliable estimation of habitual physical activity and sedentary time of children during the early years - a worked example following a stepped approach

This study presents a worked example of a stepped process to reliably estimate the habitual physical activity and sedentary time of a sample of young children. A total of 299 children (2.9 ± 0.6 years) were recruited. Outcome variables were daily minutes of total physical activity, sedentary time, moderate to vigorous physical activity and proportional values of each variable. In total, 282 (94%) provided 3 h of accelerometer data on ≥1 day and were included in a 6-step process: Step-1: determine minimum wear-time; Step-2: process 7-day-data; Step-3: determine the inclusion of a weekend day; Step-4: examine day-to-day variability; Step-5: calculate single day intraclass correlation (ICC) (2,1); Step-6: calculate number of days required to reach reliability. Following the process the results were, Step-1: 6 h was estimated as minimum wear-time of a standard day. Step-2: 98 (32%) children had ≥6 h wear on 7 days. Step-3: no differences were found between weekdays and weekend days (P ≥ 0.05). Step-4: no differences were found between day-to-day variability (P ≥ 0.05). Step-5: single day ICC’s (2,1) ranged from 0.48 (total physical activity and sedentary time) to 0.53 (proportion of moderate to vigorous physical activity). Step-6: to reach reliability (ICC = 0.7), 3 days were required for all outcomes. In conclusion following a 7 day wear protocol, ≥6 h on any 3 days was found to have acceptable reliability. The stepped-process offers researchers a method to derive sample-specific wear-time criterion.     

基于专利耦合的 中国、美国、日本锂离子电池技术前沿及差距分析

基于定量分析识别技术前沿并测度各国的技术差距具有重要的理论和现实意义。本研究初步探讨了基于专 利数据,利用文献计量学的引文耦合分析法,进行技术前沿的识别和技术差距粗略测度,并以锂离子电池为例进行实 证研究。研究结果表明,该方法所识别出来的中国、美国和日本在锂离子电池领域的技术前沿以及各国之间的技术差 距,与产业现状具有一定一致性,是一条可行的研究途径。