Comparative evaluation of heart rate-based monitors: Apple Watch vs Fitbit Charge HR

The purpose of this investigation was to examine the validity of energy expenditure (EE), steps, and heart rate measured with the Apple Watch 1 and Fitbit Charge HR. Thirty-nine healthy adults wore the two monitors while completing a semi-structured activity protocol consisting of 20 minutes of sedentary activity, 25 minutes of aerobic exercise, and 25 minutes of light intensity physical activity. Criterion measures were obtained from an Oxycon Mobile for EE, a pedometer for steps, and a Polar heart rate strap worn on the chest for heart rate. For estimating whole-trial EE, the mean absolute percent error (MAPE) from Fitbit Charge HR (32.9%) was more than twice that of Apple Watch 1 (15.2%). This trend was consistent for the individual conditions. Both monitors accurately assessed steps during aerobic activity (MAPE_Apple: 6.2%; MAPE_Fitbit: 9.4%) but overestimated steps in light physical activity. For heart rate, Fitbit Charge HR produced its smallest MAPE in sedentary behaviors (7.2%), followed by aerobic exercise (8.4%), and light activity (10.1%). The Apple Watch 1 had stronger validity than the Fitbit Charge HR for assessing overall EE and steps during aerobic exercise. The Fitbit Charge HR provided heart rate estimates that were statistically equivalent to Polar monitor.     

基于MDT单片机的Modbus远程控制器设计

针对节能监管系统数据采集网关对现场设备控制能力有限的问题,设计基于MDT单片机的Modbus远程控制器,实现了采集网关对现场设备的协作控制,以提高节能监管系统的监控效果。远程控制器以MDT单片机为核心,整合了Modbus通信协议,并通过RS485总线与数据采集网关的下行RS485主机接口互联,实现对现场控制量的监测和控制。通过实践验证,远程控制器能够可靠地实现状态量的采集和切换控制,工作稳定可靠。     

欠发达地区高校图书馆VPN实现及服务跟进

数字化改变了图书馆单一的文献资源服务,但也使得用户在资源利用方面出现了新的障碍。实现远程资源访问,是图书馆用户重要需求之一。当前SSL VPN技术为高校图书馆提供了校外资源访问的安全方式,但图书馆实现VPN后的服务跟进存在许多不足应该得到重视和解决。     

基于数据挖掘的中药成分分析——聚类分析在HPLC测定林下山参人参皂苷含量中的应用

对林下山参高效液相色谱指纹图谱进行研究,运用SPSS16.0软件包,先对样品进行相似度分析,然后用聚类分析方法对林下山参样品的主要7种人参皂苷进行分类研究,对样品进行合理的分类,揭示样品间的远近亲疏关系,这可大大缩减了以往全凭主观判断所造成的误差,使数据分析结果更具客观性,对林下山参品种与质量的鉴定有一定的理论意义和实用价值。     

一种基于 CDMA 自组网的通信网络 MAC 准同步协议

为了提高无线自组网通信网络吞吐量和数据包发送成功率,提出一种基于准同步 CDMA 的自组网MAC 协议,并对其收发电路进行设计。在采用零相关区序列的准同步 CDMA 系统中,到达接收端的各用户信号存在一定的相对时延,如果用户信号相对时延控制在零相关窗口范围之内,可以达到近似于同步的效果,同时零相关序列的相关性能大大提高了系统抗多址干扰和多径干扰能力。仿真结果表明,该协议的系统吞吐量是未采用零相关序列系统的 5 倍,在数据包发送数为 50 时仍有 30%的发送成功率。     

Assessment of the power performance of racing cyclists

A 30‐s ‘all‐out’ power protocol was studied in four groups of racing cyclists including internationals (n = 8), Category 1 (n = 10), Category 2 (n = 15) and Category 3 (n = 11). Following warm‐up each subject completed five trials interspersed by 3 min of low intensity exercise on an ergowheel racing cycle ergometry system at a power output of 15 W kg^–1 body weight, generated at 130 rev min^–1. Temporal indices of performance included delay time (DT) to achieve the power criterion, total time (TT) of the maintenance of the power criterion and the ratio of TT/DT. ‘Explosive’ leg strength was assessed from a vertical jump. The results indicated that international and Category 1 cyclists had lower DT (2.2 ± 0.1s and 2.1 +0.0s, respectively; P<0.05), higher TT (28.1 ±0.7s and 27.0+0.7s, respectively; P<0.05) and elevated TT/DT (12.8 and 12.9, respectively; P<0.01). ‘Explosive’ leg strength was also higher (P<0.05) in the internationals than in the other groups of cyclists. The protocol provides a sport‐related method for the assessment of short term endurance performance ability in racing cyclists which may be of value in identifying the anaerobic capability of individual cyclists.     

Physiological variables and performance markers of serving soldiers from two “elite” units of the British Army

Abstract

The aim of this study was to compare selected physiological variables and performance markers of soldiers from two “elite” units of the British Army. Ten soldiers from each of the two units were recruited for this study (n = 20). All participants completed three tests while carrying a 20 kg backpack load: (1) a maximal treadmill test using the Bruce protocol; (2) a 2 mile backpack run test specific to Unit A on a consistently flat tarmac road; and (3) a 29 km time-trial over hilly terrain typical of a mountainous area used by Unit B for performance assessment. Heart rate, maximal blood lactate concentration and performance (run time) were assessed during all three tests, with peak oxygen uptake also being measured during the maximal treadmill test. Measurements of anthropometry, isokinetic strength and mental toughness (MT48) were also recorded. There were no significant differences in terms of performance markers between the units (P > 0.05). Performance on the maximal treadmill test correlated with performance on the 2 mile backpack run test (r = ?0.57) and 29 km time-trial (r = ?0.66). Performance on the 2 mile backpack run test in turn correlated with 29 km time-trial performance (r = ?0.77), accounting for 59% of the variance. In conclusion, the maximal treadmill test and the 2 mile backpack run test are useful indicators of performance on the arduous hill march and could be employed in the screening and selection of potential recruits.     

VoIP中SIP呼叫在三网合一交换机中的实现

详细地描述了VoIP(Voice over Internet Protocol)的SIP呼叫在三网合一交换机中实现过程,讨论了SIP呼叫的处理流程,用开源的oSIP协议栈实现SIP呼叫。包括注册,电话号码处理,以及接通和挂断处理。从原理上描述了SIP呼叫在三网合一交换机中的具体实现。分析了SIP协议栈的运行机制,设计了将SIP协议栈移植到三网合一交换机,并以此为基础开发基于SIP呼叫的实现方案。     

基于最优多属性约束的IPV6动态路由协议优化

提出一种基于最优多属性约束的IPV6动态路由协议优化方法。根据IPV6动态路由协议中数据属性的约束条件,建立最优多属性约束模型,用来描述不同属性约束条件需要符合的要求。详细描述了IPV6动态路由协议的设计方式,从而实现大范围网络通信。实验结果表明,利用这种方法进行网络通信,能够避免传统算法的缺陷,提高了通信效率,取得了令人满意的结果。     

有关口语报告法效度的几个争议问题

尽管口语报告法在当前心理学、教育学以及认知科学的研究中被广泛使用,但关于其效度的争议依然存在。这些争议主要包括:第一,口语报告的准确性,即口语报告能否准确地反映我们的思维内容?第二,口语报告的完整性,即搜集到的口语报告能否为我们了解被试的认知过程提供足够的信息?第三,口语报告的反应性,即口语报告是否会影响思维的正常进程?文章对这些问题进行了较为深入的分析和思考,并指出了对口语报告法进行研究的几个新趋势。