3,460 research outputs found
High resolution dynamical mapping of social interactions with active RFID
In this paper we present an experimental framework to gather data on
face-to-face social interactions between individuals, with a high spatial and
temporal resolution. We use active Radio Frequency Identification (RFID)
devices that assess contacts with one another by exchanging low-power radio
packets. When individuals wear the beacons as a badge, a persistent radio
contact between the RFID devices can be used as a proxy for a social
interaction between individuals. We present the results of a pilot study
recently performed during a conference, and a subsequent preliminary data
analysis, that provides an assessment of our method and highlights its
versatility and applicability in many areas concerned with human dynamics
The survey on Near Field Communication
PubMed ID: 26057043Near Field Communication (NFC) is an emerging short-range wireless communication technology that offers great and varied promise in services such as payment, ticketing, gaming, crowd sourcing, voting, navigation, and many others. NFC technology enables the integration of services from a wide range of applications into one single smartphone. NFC technology has emerged recently, and consequently not much academic data are available yet, although the number of academic research studies carried out in the past two years has already surpassed the total number of the prior works combined. This paper presents the concept of NFC technology in a holistic approach from different perspectives, including hardware improvement and optimization, communication essentials and standards, applications, secure elements, privacy and security, usability analysis, and ecosystem and business issues. Further research opportunities in terms of the academic and business points of view are also explored and discussed at the end of each section. This comprehensive survey will be a valuable guide for researchers and academicians, as well as for business in the NFC technology and ecosystem.Publisher's Versio
Spatial Identification Methods and Systems for RFID Tags
DisertaÄŤnĂ práce je zaměřena na metody a systĂ©my pro měřenĂ vzdálenosti a lokalizaci RFID tagĹŻ pracujĂcĂch v pásmu UHF. Ăšvod je vÄ›nován popisu souÄŤasnĂ©ho stavu vÄ›deckĂ©ho poznánĂ v oblasti RFID prostorovĂ© identifikace a struÄŤnĂ©mu shrnutĂ problematiky modelovánĂ a návrhu prototypĹŻ tÄ›chto systĂ©mĹŻ. Po specifikaci cĂlĹŻ disertace pokraÄŤuje práce popisem teorie modelovánĂ degenerovanĂ©ho kanálu pro RFID komunikaci. DetailnÄ› jsou rozebrány metody měřenĂ vzdálenosti a odhadu smÄ›ru pĹ™Ăchodu signálu zaloĹľenĂ© na zpracovánĂ fázovĂ© informace. Pro účely lokalizace je navrĹľeno nÄ›kolik scĂ©nářů rozmĂstÄ›nĂ antĂ©n. Modely degenerovanĂ©ho kanálu jsou simulovány v systĂ©mu MATLAB. VĂ˝znamná část tĂ©to práce je vÄ›nována konceptu softwarovÄ› definovanĂ©ho rádia (SDR) a specifikĹŻm jeho adaptace na UHF RFID, která vyuĹľitĂ běžnĂ˝ch SDR systĂ©mĹŻ znaÄŤnÄ› omezujĂ. Diskutována je zejmĂ©na problematika prĹŻniku nosnĂ© vysĂlaÄŤe do pĹ™ijĂmacĂ cesty a poĹľadavky na signál lokálnĂho oscilátoru pouĹľĂvanĂ˝ pro směšovánĂ. Prezentovány jsou tĹ™i vyvinutĂ© prototypy: experimentálnĂ dotazovaÄŤ EXIN-1, měřicĂ systĂ©m zaloĹľenĂ˝ na platformÄ› Ettus USRP a antĂ©nnĂ pĹ™epĂnacĂ matice pro emulaci SIMO systĂ©mu. ZávÄ›reÄŤná část je zaměřena na testovánĂ a zhodnocenĂ popisovanĂ˝ch lokalizaÄŤnĂch technik, zaloĹľenĂ˝ch na měřenĂ komplexnĂ pĹ™enosovĂ© funkce RFID kanálu. Popisuje ĂşzkopásmovĂ©/širokopásmovĂ© měřenĂ vzdálenosti a metody odhadu smÄ›ru signálu. Oba navrĹľenĂ© scĂ©náře rozmĂstÄ›nĂ antĂ©n jsou v závÄ›ru ověřeny lokalizaÄŤnĂm měřenĂm v reálnĂ˝ch podmĂnkách.The doctoral thesis is focused on methods and systems for ranging and localization of RFID tags operating in the UHF band. It begins with a description of the state of the art in the field of RFID positioning with short extension to the area of modeling and prototyping of such systems. After a brief specification of dissertation objectives, the thesis overviews the theory of degenerate channel modeling for RFID communication. Details are given about phase-based ranging and direction of arrival finding methods. Several antenna placement scenarios are proposed for localization purposes. The degenerate channel models are simulated in MATLAB. A significant part of the thesis is devoted to software defined radio (SDR) concept and its adaptation for UHF RFID operation, as it has its specialties which make the usage of standard SDR test equipment very disputable. Transmit carrier leakage into receiver path and requirements on local oscillator signals for mixing are discussed. The development of three experimental prototypes is also presented there: experimental interrogator EXIN-1, measurement system based on Ettus USRP platform, and antenna switching matrix for an emulation of SIMO system. The final part is focused on testing and evaluation of described positioning techniques based on complex backscatter channel transfer function measurement. Both narrowband/wideband ranging and direction of arrival methods are validated. Finally, both proposed antenna placement scenarios are evaluated with real-world measurements.
Wireless Sensor Enabled Public Transportation System
Automatic Vehicle Identification (AVI) in real time is becoming an urgent necessity due to rapid increase in the number of vehicles on roads. The Radio Frequency Identification (RFID) Technology can be used for vehicle identification to gather information in real-time from roads by getting the vehicles location from RFID readers placed in the vehicle. This paper focuses on designing the Public Vehicle Location System (PVLS). The proposed structure consists of passive RFID tags placed at various locations on the chosen route, RFID reader on the Bus, wireless communication with a PC and commanding software (RFID reader and database structure), also PVLS applications and website. The designed system controls, manages and monitors the performance of RFID readers. It also filters and stores the information in an appropriate format so that it could be used without difficulty in the application system and website. The system implemented by using RFID is placed in the Bus which is programmed by Visual C# 2008 with Compact .Net Framework
Performance of the LHCb vertex locator
The Vertex Locator (VELO) is a silicon microstrip detector that surrounds the proton-proton interaction region in the LHCb experiment. The performance of the detector during the first years of its physics operation is reviewed. The system is operated in vacuum, uses a bi-phase CO2 cooling system, and the sensors are moved to 7 mm from the LHC beam for physics data taking. The performance and stability of these characteristic features of the detector are described, and details of the material budget are given. The calibration of the timing and the data processing algorithms that are implemented in FPGAs are described. The system performance is fully characterised. The sensors have a signal to noise ratio of approximately 20 and a best hit resolution of 4 ÎĽm is achieved at the optimal track angle. The typical detector occupancy for minimum bias events in standard operating conditions in 2011 is around 0.5%, and the detector has less than 1% of faulty strips. The proximity of the detector to the beam means that the inner regions of the n+-on-n sensors have undergone space-charge sign inversion due to radiation damage. The VELO performance parameters that drive the experiment's physics sensitivity are also given. The track finding efficiency of the VELO is typically above 98% and the modules have been aligned to a precision of 1 ÎĽm for translations in the plane transverse to the beam. A primary vertex resolution of 13 ÎĽm in the transverse plane and 71 ÎĽm along the beam axis is achieved for vertices with 25 tracks. An impact parameter resolution of less than 35 ÎĽm is achieved for particles with transverse momentum greater than 1 GeV/c
Near Field Communication: From theory to practice
This book provides the technical essentials, state-of-the-art knowledge, business ecosystem and standards of Near Field Communication (NFC)by NFC Lab - Istanbul research centre which conducts intense research on NFC technology. In this book, the authors present the contemporary research on all aspects of NFC, addressing related security aspects as well as information on various business models. In addition, the book provides comprehensive information a designer needs to design an NFC project, an analyzer needs to analyze requirements of a new NFC based system, and a programmer needs to implement an application. Furthermore, the authors introduce the technical and administrative issues related to NFC technology, standards, and global stakeholders. It also offers comprehensive information as well as use case studies for each NFC operating mode to give the usage idea behind each operating mode thoroughly. Examples of NFC application development are provided using Java technology, and security considerations are discussed in detail. Key Features: Offers a complete understanding of the NFC technology, including standards, technical essentials, operating modes, application development with Java, security and privacy, business ecosystem analysis Provides analysis, design as well as development guidance for professionals from administrative and technical perspectives Discusses methods, techniques and modelling support including UML are demonstrated with real cases Contains case studies such as payment, ticketing, social networking and remote shopping This book will be an invaluable guide for business and ecosystem analysts, project managers, mobile commerce consultants, system and application developers, mobile developers and practitioners. It will also be of interest to researchers, software engineers, computer scientists, information technology specialists including students and graduates.Publisher's Versio
Improving the Performance and Endurance of Persistent Memory with Loose-Ordering Consistency
Persistent memory provides high-performance data persistence at main memory.
Memory writes need to be performed in strict order to satisfy storage
consistency requirements and enable correct recovery from system crashes.
Unfortunately, adhering to such a strict order significantly degrades system
performance and persistent memory endurance. This paper introduces a new
mechanism, Loose-Ordering Consistency (LOC), that satisfies the ordering
requirements at significantly lower performance and endurance loss. LOC
consists of two key techniques. First, Eager Commit eliminates the need to
perform a persistent commit record write within a transaction. We do so by
ensuring that we can determine the status of all committed transactions during
recovery by storing necessary metadata information statically with blocks of
data written to memory. Second, Speculative Persistence relaxes the write
ordering between transactions by allowing writes to be speculatively written to
persistent memory. A speculative write is made visible to software only after
its associated transaction commits. To enable this, our mechanism supports the
tracking of committed transaction ID and multi-versioning in the CPU cache. Our
evaluations show that LOC reduces the average performance overhead of memory
persistence from 66.9% to 34.9% and the memory write traffic overhead from
17.1% to 3.4% on a variety of workloads.Comment: This paper has been accepted by IEEE Transactions on Parallel and
Distributed System
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