Method of Time Series Similarity Measurement Based on Dynamic Time Warping

With the rapid development of mobile communication all over the world,the similarity of mobile phone communication data has received widely attention due to its advantage for the construction of smart cities.Mobile phone communication data can be regarded as a type of time series and dynamic time warping(DTW)and derivative dynamic time warping(DDTW)are usually used to analyze the similarity of these data.However,many traditional methods only calculate the distance between time series while neglecting the shape characteristics of time series.In this paper,a novel hybrid method based on the combination of dynamic time warping and derivative dynamic time warping is proposed.The new method considers not only the distance between time series,but also the shape characteristics of time series.We demonstrated that our method can outperform DTW and DDTW through extensive experiments with respect to cophenetic correlation.

纳米荧光粉YPO4:2%Sm^3+水热工艺条件的优化及荧光性能

以荧光强度为指标,采用L9(3^4)正交实验优化纳米荧光粉YPO4:2%Sm^3+的水热工艺条件(反应温度、反应时间、溶液的阴/阳离子比和pH值)。用X射线衍射仪(XRD)、扫描电镜及能谱(SEM and EDS)、荧光分光光度计(FL)、红外光谱仪(FT-IR)和紫外光谱仪(UV)等仪器对样品的组成、结构、形貌及其发光性能进行了表征和分析。结果表明,影响纳米荧光粉YPO4:2%Sm^3+水热工艺条件的主次因素为反应温度>pH值>反应时间>阴/阳离子比。最佳的水热工艺条件为反应温度为200℃、pH=3、反应时间为12 h、阴/阳离子比3:1。最佳纳米荧光粉的结构为单一的四方晶体结构,形貌为纳米球,荧光强度最大,荧光寿命为0.1719ms,禁带宽度为5.14 eV,色坐标为X=0.556 3, Y=0.433 9。

Soft,stretchable,wireless intelligent three-lead electrocardiograph monitors with feedback functions for warning of potential heart attack

Cardiovascular diseases(CVDs)are fatal chronic diseases,where electrocardiography(ECG)monitoring could be a prominent solution for early diagnosis.In spite of available commercialized,multilead ECG devices,bulky formats,discontinuous monitoring,and no safety alarm system significantly limit their practical applications.Herein,we present a soft,and stretchable,three-lead ECG device allowing continuous monitoring and wireless transmission of ECG signals.A newly developed organohydrogel patch with a strong adhesive ability(~9.9 kPa)and higher conductivity(~6.5 kΩ)is applied for high-quality ECG signals collection.With a long operation duration(6.5 h)and wireless transmission distance(20.9 m),it could fulfill most of the daily applications.Machine learning algorithms and the graphical user interface are used for real-time ECG monitoring and cardiac abnormalities diagnosis.The vibratory flexible actuator,which is triggered by cardiac abnormalities that need immediate medical treatment,is also integrated as a warning system for the user.As a newly reported stretchable multi-lead ECG device for long-term ECG signal monitoring,there is a high potential for improving users'life quality with the high-risk population of CVDs.

A novel and effective multi-constrained QoS routing scheme in WMNs

Multi-constrained quality of service(QoS)routing aims at finding an optimal path that satisfies a set of QoS parameters,as an NP complete problem,which is also a big challenge for wireless mesh networks(WMNs).Heuristic algorithms with polynomial and pseudo-polynomial-time complexities are often used to deal with this problem.However,existing solutions,most of which suffered either from excessive computational complexities or from low performance,were proposed only for wired networks and cannot be used directly in wireless mesh networks.In this paper,we propose a novel routing scheme based on mean field annealing(MFA-RS)to solve this problem.MFA-RS first uses a function of two QoS parameters,wireless link’s delay and transmission success rate as the cost function,and then seeks to find a feasible path by MFA.Because MFA-RS uses a set of deterministic equations to replace the stochastic process in simulated annealing(SA)and uses saddle point approximation in the calculation of the stationary probability distribution at equilibrium,the convergence time is much less than the routing scheme based on SA(SA-RS).Simulation results demonstrate that MFA-RS is an effective algorithm and is very fit for WMNs.