Indoor Environment and Human Sensing via Millimeter Wave Radio:A Review

With the rapid development of 5G technology,more and more attention has been attracted to mmWave sensing.As an emerging sensing medium,mmWave has the advantages of both high sensitivity and precision.Different from its networking applications,the core method of mmWave sensing is to analyze the reflected signal changes containing the relevant information of different surrounding environments.In this paper,we conduct a systemic review for mmWave sensing.We first summarize the prior works on environmental sensing with different signal analysis methods.Then,we classify and discuss the work of sensing humans,including their behavior and gestures.Finally,we discuss and put forward more possibilities of mmWave human perception.

Superflexible and Lead-Free Piezoelectric Nanogenerator as a Highly Sensitive Self-Powered Sensor for Human Motion Monitoring

For traditional piezoelectric sensors based on poled ceramics,a low curie tem-perature(T_(c))is a fatal flaw due to the depolarization phenomenon.However,in this study,we find the low T_(c) would be a benefit for flex-ible piezoelectric sensors because small alterations of force trig-ger large changes in polarization.BaTi_(0.88)Sn_(0.12)O_(3)(BTS)with high piezoelectric coefficient and low T_(c) close to human body temperature is taken as an example for materials of this kind.Continuous piezo-electric BTS films were deposited on the flexible glass fiber fabrics(GFF),self-powered sensors based on the ultra-thin,superflexible,and polarization-free BTS-GFF/PVDF composite piezoelectric films are used for human motion sensing.In the low force region(1-9 N),the sensors have the outstanding performance with voltage sensitivity of 1.23 V N^(−1) and current sensitivity of 41.0 nA N^(−1).The BTS-GFF/PVDF sensors can be used to detect the tiny forces of falling water drops,finger joint motion,tiny surface deformation,and fatigue driving with high sensitivity.This work provides a new paradigm for the preparation of superflexible,highly sensitive and wearable self-powered piezoelectric sensors,and this kind of sensors will have a broad application prospect in the fields of medical rehabilitation,human motion monitoring,and intelligent robot.

Privacy-preserving human activity sensing:A survey

With the prevalence of various sensors and smart devices in people’s daily lives,numerous types of information are being sensed.While using such information provides critical and convenient services,we are gradually exposing every piece of our behavior and activities.Researchers are aware of the privacy risks and have been working on preserving privacy while sensing human activities.This survey reviews existing studies on privacy-preserving human activity sensing.We first introduce the sensors and captured private information related to human activities.We then propose a taxonomy to structure the methods for preserving private information from two aspects:individual and collaborative activity sensing.For each of the two aspects,the methods are classified into three levels:signal,algorithm,and system.Finally,we discuss the open challenges and provide future directions.

Feasibility study on buoyancy-weight ratios of a submerged floating tunnel prototype subjected to hydrodynamic loads

The research progress of a novel traffic solution,a submerged floating tunnel（SFT）,is reviewed in terms of a study approach and loading scenario.Among existing publications,the buoyancy-weight ratio（BWR） is usually predefined.However,BWR is a critical structural parameter that tremendously affects the dynamic behaviour of not only the tunnel tube itself but also the cable system.In the context of a SFT prototype（SFTP） project in Qiandao Lake（Zhejiang Province,China）,the importance of BWR is illustrated by finite element analysis and subsequently,an optimized BWR is proposed within a reasonable range in the present study.In the numerical model,structural damping is identified to be of importance.Rayleigh damping and the corresponding Rayleigh coefficients are attained through a sensitivity study,which shows that the adopted damping ratios are fairly suitable for SFTP.Lastly,the human sense of security is considered by quantifying the comfort index,which helps further optimize BWR in the SFTP structural parameter design.

High-performance Si/VO_(2)-nanorod heterojunction photodetector based on photothermoelectric effect for detecting human radiation

As a typical candidate of optoelectronic materials,vanadium dioxide(VO_(2))has wide applications in photodetectors(PDs),but is still challenging in largely enhancing the photodetecting performance for low-power human radiation.Herein,high-performance Si/VO_(2)nanorods(NRs)heterojunction PDs based on the photothermoelectric(PTE)effect are presented.The uniform VO_(2)-NRs array films were deposited on Si by using magnetron sputtering technique,and a Si/VO_(2)heterojunctions were fabricated.The device exhibits a four-stage photoresponse and broadband photoresponse from ultraviolet to long-wavelength infrared.Benefited from the unique nanorods structure and the strong PTE effect,the fabricated device exhibits a large enhancement of the photodetecting performance,showing an ultrahigh photodetectivity of 1.6×10^(13)Jones and ultrafast response rates with a risingedge time of~65.0μs,three orders of magnitude higher than other VO_(2)-based devices.Furthermore,the device exhibits unique abilities to detect human radiation even when the human fingers are far away from the device surface up to 10.0 cm.Additionally,the fabricated Si/VO_(2)devices can also be applied as breath sensors to distinguish different breathing patterns.These results supply an effective route to design high-performance photodetectors toward detecting human thermal radiation and respiration.

Quantification of Blur and Its Applications

Human visual sense has two aspects in our feeling for blurred image, that is, one is the amount of blur depending on object size, the other is the amount of blur independent of the object size. In the former for example, when the image size becomes larger, the author feels smaller amount blur. The quantitative evaluation based on entropy for blurred images is proposed in this paper. The author calls this metric ＂variation entropy＂. This metric has two kinds of aspects that coincide with the human visual sense. The first is the absolute evaluation of blur, and the second is the relative evaluation of blur. The former can be quantified by variation entropy for a unit boundary length （or L-type variation entropy： HL ）, which is dependent on resolution, and the latter can be quantified by variation entropy for a unit area （or A-type variation entropy： H^A ）, which is independent of resolution. These two metrics have complementary properties. At last, two variation entropies are applied to the standard kanji character database, and then the strong relation between variation entropy and accuracy of recognition is discussed. The tendency of writing skills for grades is evaluated by applying the metric to a database collected from school children.

Theory, System and Policy Proposals on New Factor Supply for Higher-Stage Development in China

By introducing the knowledge sector, this paper has structurally redefined the production function and on such a basis, analyzed the role of new factor supply in China's economic transition and reached the following conclusions: 1) The supply of new production factors represented by knowledge sector has become the dominant force that decides whether China can overcome the barrier of structural deceleration, and achieve sustained growth and stride into a higher stage of development; 2) In the context of rising urban household income and upgrading demand, the knowledge sector has emerged, encompassing science and technology, culture, health and sports that contribute to enhanced "human capital in the broad sense", and the production and consumption process of the knowledge sector is also the process of human capital improvement and endogenous innovation; 3) Aside from its endogeneity, the knowledge sector creates spillover effects that will revitalize traditional industries and services, remove the barriers between consumption and production, and promote structural transition and economic upgrade for innovationdriven growth; 4) In the context of flagging growth driven by material capital, great importance should be attached to the contribution of consumption to human capital in the broad sense and promote the interactive upgrade of consumption and production structures, which are the key to overcoming the bottlenecks of development.

An Advanced Scheme of Compressed Sensing of Acceleration Data for Telemonintoring of Human Gait

The compressed sensing (CS) of acceleration data has been drawing increasing attention in gait telemonitoring application. In such application, there still exist some challenging issues including high energy consumption of body-worn device for acceleration data acquisition and the poor reconstruction performance due to nonsparsity of acceleration data. Thus, the novel scheme of compressive sensing of acceleration data is needed urgently for solutions that are found to these issues.

Sensorless Sensing with WiFi

Can WiFi signals be used for sensing purpose？ The growing PHY layer capabilities of WiFi has made it possible to reuse WiFi signals for both communication and sensing. Sensing via WiFi would enable remote sensing without wearable sensors, simultaneous perception and data transmission without extra communication infrastructure, and contactless sensing in privacy-preserving mode. Due to the popularity of WiFi devices and the ubiquitous deployment of WiFi networks, WiFi-based sensing networks, if fully connected, would potentially rank as one of the world＇s largest wireless sensor networks. Yet the concept of wireless and sensorless sensing is not the simple combination of WiFi and radar. It seeks breakthroughs from dedicated radar systems, and aims to balance between low cost and high accuracy, to meet the rising demand for pervasive environment perception in everyday life. Despite increasing research interest, wireless sensing is still in its infancy. Through introductions on basic principles and working prototypes, we review the feasibilities and limitations of wireless, sensorless, and contactless sensing via WiFi. We envision this article as a brief primer on wireless sensing for interested readers to explore this open and largely unexplored field and create next-generation wireless and mobile computing applications.

A Clinical Data Analysis Based Diagnostic Systems for Heart Disease Prediction Using Ensemble Method

The correct diagnosis of heart disease can save lives,while the incorrect diagnosis can be lethal.The UCI machine learning heart disease dataset compares the results and analyses of various machine learning approaches,including deep learning.We used a dataset with 13 primary characteristics to carry out the research.Support vector machine and logistic regression algorithms are used to process the datasets,and the latter displays the highest accuracy in predicting coronary disease.Python programming is used to process the datasets.Multiple research initiatives have used machine learning to speed up the healthcare sector.We also used conventional machine learning approaches in our investigation to uncover the links between the numerous features available in the dataset and then used them effectively in anticipation of heart infection risks.Using the accuracy and confusion matrix has resulted in some favorable outcomes.To get the best results,the dataset contains certain unnecessary features that are dealt with using isolation logistic regression and Support Vector Machine(SVM)classification.

新型杂化金属硫氰化物压电体用于能量收集和动作传感

杂化有机-无机压电材料因其电光性能优异、合成简单以及机械柔性等优点而受到广泛关注,在能源和传感领域显示出巨大的应用潜力.本文合成了一例新的零维杂化压电材料[Me-V]_(3)Mn(SCN)_(5),并与聚己二酸丁二酯对苯二甲酸丁二酯复合成膜制备了用于机械能收集的压电器件.实验结果表明,15 wt%组分的压电器件具有优异的能量收集性能,在仅0.03 MPa作用力下,可产生18.49 V的最大输出电压和7.88μW cm^(-2)的功率密度.同时,该器件在循环5500圈及60天内仍保持优异的压电性能.此外,该器件在包括手指敲击、手腕/肘部弯曲和踩踏等动作传感方面表现出良好的敏感性.这项工作证明了无铅无卤的杂化压电材料在柔性传感和能量收集方面具有巨大的应用潜力.