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关键词： SAW   temperature   sensor   package-less   SHM   simulation  

摘要： Surface acoustic wave sensors are a promising solution for structural health monitoring applications. They can withstand extreme operating conditions. However, they often fail in operation due to housing issues. In this work, we propose to use an innovative package-less structure in order to fully get rid of the latter. The package-less concept is based on a multilayer substrate whose thicknesses have been designed to ensure an acoustic mode propagating far from the sensor surface and a sensor that can be wirelessly interrogated at 2.45 GHz. The sensitivity to temperature of the guided acoustic mode velocity was determined using finite element simulation. From this calculation, the temperature sensitivity of the sensor was evaluated. In addition, coupling of modes parameters and time signature of the sensor were estimated. The obtained results, limitations and expected technical challenges are discussed as a closure.

关键词： RFID Generation-2   Unreliable channels   Performance modeling   Performance analyses  

摘要： EPCglobal Class-1 Generation-2 (RFID Generation-2) is a wireless communication system in Internet of Things. The models and analyses of RFID Generation-2 are important and have been reported. However, for usefulness and validity, existing models and analyses are mainly based on the assumptions that RFID runs in ideal wireless channels (no packet loss, no error code, and no capture effect). However, there are three co-existing these bad results (packet loss, error code, and capture effect) in the realistic channels, which means that the channels are unreliable. For obtaining comprehensive understanding of RFID Generation-2 performance to conduct relevant important researches, some models are developed for RFID Generation-2 under the unreliable channels. Meanwhile, four feasible methods for calculating the probabilities of those bad results (as models parameters) are given. After validating accuracy of the models through extensive simulation experiments and their fitness for an instance, these models are used to analyze impacts of the parameters on time efficiency, and obtain some key sensitivity factors promoting efficiency. Furthermore, analytical results demonstrate that the analyses considering those co-existing bad results are basis for the researches of some fields such as the general tag identification, the blocked tags identification, the missing tag identification, and the effective hardware design.

关键词： Radiofrequency identification   Protocols   Multiaccess communication   Internet of Things   Temperature sensors   Frequency synchronization   Code-division multiple access (CDMA)   cosets   group theory   massive network   orthogonal accessing control   query tree (QT)  

摘要： In radio-frequency identification (RFID)-based sensors networks, each sensor is integrated with a tag and sensors may co-exist in an area of interest. Before sending data packets, the sensors send their IDs for channel reservations. However, ID collisions happen frequently at the reservation stage which leads to significant time delays, especially for massive and dense networks. In this article, by employing group theory, we show that for B = 2(k), where k is a positive integer, the set {-1,+1}(B) and the Hadamard product. forms a group {{-1,+1}(B), o} that can be divided into (2(B)/B) disjoint subsets, each of which has B binary vectors that are mutually orthogonal. Based on this finding, we propose orthogonal coset identification (OCSID) and its generalization, query tree (QT)-OCSID, that can recover ID information from collisions, and thus considerably improve the efficiency at the reservation stage, particularly when the network is large and/or dense. In an ideal case, it can recover/decode B tags for each query. The fundamental difference between the proposed OCSID schemes and code-division multiple access-based schemes is that, OCSID achieves orthogonal design for ID information recovery by exploiting the inherent orthogonal structure of the binary vector set, instead of spreading the spectrum. Hence, it requires a narrower frequency band, lower circuit complexity, and lower synchronization precision, which are much more preferred by hardware limited devices.

关键词： RFID技术   军队   仓储管理   应用  

摘要： 当前军队在进行仓储管理中,所涉及到的人力物力程度较大,而且还需要科学合理的安排仓库以及对一些存储货物控制和管理。仓促管理的顺利进行是保证军队货物管理的关键所在。但是随着时代的发展,军队仓储管理中的技术水平较低,而且严重的影响了军队的仓储管理工作。而RFID技术可以应用在军队仓储管理的工作中,提升仓储管理中的技术水平,减少一些人力物力的成本消耗,缩短了工作的时间并且提高了工作的效率,进一步的促进了针对仓储管理的进度。

关键词： Radar   Radar cross-sections   Doppler radar   Radar detection   Backscatter   Sensors   Frequency modulation   Backscattering   FMCW radar   micro-Doppler   modulated transponder   pedestrian detection   millimeter band sensors   RFID  

摘要： This work asses a way to improve the detection of pedestrians, workers or cyclists, but also other static elements on the road. These elements due to its low radar cross-section can be masked by other larger objects close to them, when they are illuminated by an automotive radar. Rotating backscatter is proposed to enhance the detection with automotive FMCW radars due to the introduction of a differentiable micro-Doppler signature. A comprehensive theory of operation is explained in this paper. Simulated and experimental results are presented at 24 GHz for transponder detection in presence of strong clutter in range-velocity maps.

关键词： RFID   Telecare Medical Information Systems   Health-care   Authentication   Secret disclosure attack   Real-or-Random model   AVISPA   Scyther  

摘要： The development of technology has accelerated things and solved many problems. Among various technologies, the integration of the Internet of Things (IoT) into human social life brings the promise of an easier and better life. The integration of IoT into the medical field, as well as the environments and patients associated with it, has provided a new context called the Telecare Medical Information Systems. It should be noted that the smart medicine, in addition to its significant benefits, carries many security threats, so privacy and especially anonymity is the largest concern in implementing a telecare medical information system. Due to the importance of privacy preservation and security in smart health-care systems, Fan et al. have recently proposed a lightweight authentication protocol (IEEE Netw. 33 (2) (2019)) using quadratic residue and pseudo random number generators, to be used in this platform. They believed that their scheme has enough security, privacy preservation, and also good resistance to various attacks including tag traceability attacks, replay attacks and also de-synchronization (DoS) attacks. The aim of the present study is to examine the security of the mentioned protocol. In fact, a heuristic attack was presented, in which an adversary could retrieve tag's and reader's current and previous identifier that contradicts anonymity and forward untraceability properties of this protocol. Reader and tag impersonation attacks were also applied against the protocol. Besides, a lightweight authentication protocol was proposed for cloud-based health-care systems called LAPCHS. Security analysis of our new protocol, through heuristic security analysis and also formal evaluations using Real-or-Random Model and simulations done on the AVISPA and the Scyther tools, confirms its security against different attacks.

关键词： Spatiotemporal risk   RFID   Wearable proximity sensors   Spatiotemporal simulation   Healthcare-associated infections   Transmission   Hand hygiene compliance  

摘要： BackgroundHand transmission of harmful microorganisms may lead to infections and poses a major threat to patients and healthcare workers in healthcare settings. The most effective countermeasure against these transmissions is the adherence to spatiotemporal hand hygiene policies, but adherence rates are relatively low and vary over space and time. The spatiotemporal effects on hand transmission and spread of these microorganisms for varying hand hygiene compliance levels are unknown. This study aims to (1) identify a healthcare worker occupancy group of potential super-spreaders and (2) quantify spatiotemporal effects on the hand transmission and spread of harmful microorganisms for varying levels of hand hygiene compliance caused by this *** data were collected in a hospital ward of an academic hospital using radio frequency identification technology for 7 days. A potential super-spreader healthcare worker occupation group was identified using the frequency identification sensors' contact data. The effects of five probability distributions of hand hygiene compliance and three harmful microorganism transmission rates were simulated using a dynamic agent-based simulation model. The effects of initial simulation assumptions on the simulation results were quantified using five risk ***, doctors and patients are together responsible for 81.13% of all contacts. Nurses made up 70.68% of all contacts, which is more than five times that of doctors (10.44%). This identifies nurses as the potential super-spreader healthcare worker occupation group. For initial simulation conditions of extreme lack of hand hygiene compliance (5%) and high transmission rates (5% per contact moment), a colonised nurse can transfer microbes to three of the 17 healthcare worker or patients encountered during the 98.4min of visiting 23 rooms while colonised. The harmful microorganism transmission potential for nurses is higher during weeknights (5pm - 7am)

关键词： Smartphones  

摘要： Better access control system security comes at a higher price. It many cases the price is too high for small companies, leaving them vulnerable with cheap and insecure systems. In this work we introduce an alternative access control scheme, which improves access control security while lowering the cost. In the proposed model, passive RFID tags are mounted near a turnstile or a smart door. Tag reading and programming is done via NFC chip directly on the users smartphone. To enhance security, together with smartphone-based authorization we require the user to provide his photograph while entering a secure gate. The photograph is then displayed on a monitoring dashboard side-by-side with the registration picture, so that the two can be matched against each other. The developed client-server application offers administrative system used to configure gate access policies and monitor entrances with filters by access time, user and gate. Also, we propose a mobile application that allows gate registration and serves as a door unlock key. The suggested access control model reduces installation costs required, while maintaining good security. The system is fully wireless and uses cheap autonomous RFID-tags as its main component. We hope, that the proposed system architecture will find its application in small to medium-sized companies. Copyright © 2021, The Authors. All rights reserved.

关键词： 堆取料机   RFID技术   远程控制   现场总线技术  

摘要： 本文提出的基于RFID技术将穹顶仓堆取料机的操作改为远程控制方式是以RFID技术为核心,在Controlnet现场总线技术和视频监控系统的基础上实现的。以Ethernet协议构建的通讯系统,监控系统辅助操作人员对料场全景、吃料深度、堆料机构等设备进行监控,RFID系统对堆、取料机构进行位置检测并实现数据校正的关键环节,从而实现保证安全的前提下,使人员脱离粉尘和噪音较大的生产现场,从根本上切断职业健康粉风险源。本文同时介绍远程操作系统设计中RFID技术、现场总线技术、视频监控技术与PLC系统软件上的融合,将操作台硬点操作转换成RSView32界面操作的相关设计与实现。

关键词： RFID技术   仓储管理系统   系统集成   应用研究  

摘要： 近些年来,随着我国新一代信息技术的不断发展,传统生产模式已经难以适用于信息化发展背景当中。在这样的发展态势下,这行业生产领域需要主动结合新一代信息技术优势,实现对传统管理模式以及生产模式的创新改造。针对于此,主要以RFID技术为研究对象,重点针对RFID技术在仓储管理系统中的应用实践问题进行研究与分析,以期可以为我国仓储管理系统的信息化发展提供良好的保障。