| 1. |
- Nilsson, Emil, et al.
(författare)
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A low power-long range active RFID-system consisting of active RFID backscatter transponders
- 2010
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Ingår i: 2010 IEEE International Conference on RFID-Technology and Applications (RFID-TA). - Piscataway, N.J. : IEEE Press. - 9781424466986 ; , s. 26-30, s. 26-30
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Konferensbidrag (refereegranskat)abstract
- In this paper we present a novel active radio frequency identification system consisting of transponders with low complexity, low power consumption, and long system reading range. The transponder’s low complexity and small circuit integration area indicate that the production cost is comparable to the one of a passive tag. The hardware keystone is the transponder’s radio wake-up transceiver, which is a single oscillator with very low power consumption. The communication protocol, based on frequency signalling binary tree, contributes to the low complexity of the tag architecture. More than 1500 tags can be read per second. The average transponder ID read-out delay is 319 ms when there are 1000 transponders within reach of the interrogator. The calculated expected life time for a transponder is estimated to be almost three years.
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| 2. |
- Nilsson, Emil, et al.
(författare)
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A Pharmaceutical Anti-counterfeiting Method Using Time Controlled Numeric Tokens
- 2011
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Ingår i: 2011 IEEE International Conference on RFID-Technologies and Applications. - Piscataway, NJ : IEEE Press. - 9781457700286 ; , s. 335-339
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Konferensbidrag (refereegranskat)abstract
- An anti-counterfeit and authentication method usingtime controlled numeric tokens enabling a secure logistic chain ispresented. Implementation of the method is illustrated with apharmaceutical anti-counterfeit system. The method uses activeRFID technology in combination with product seal. Authenticityis verified by comparing time controlled ID-codes, i.e. numerictokens, stored in RFID tags and by identical numeric tokensstored in a secure database. The pharmaceutical products areprotected from the supplier to the pharmacist, with thepossibility to extend the authentication out to the end customer.The ability of the method is analyzed by discussion of severalpossible scenarios. It is shown that an accuracy of 99.9% tellingthe customer she has an authentic product is achieved by the useof 11-bit ID-code strings.
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| 3. |
- Friel, Ross, Dr, 1982-, et al.
(författare)
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3D Printed Radar Lenses with Anti-Reflective Structures
- 2019
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Ingår i: Designs. - Basel : MDPI. - 2411-9660. ; 3:2
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Tidskriftsartikel (refereegranskat)abstract
- Background: The purpose of this study was to determine if 3D printed lenses with wavelength specific anti-reflective (AR) surface structures would improve beam intensity and thus radar efficiency for a Printed Circuit Board (PCB)-based 60 GHz radar. This would have potential for improved low-cost radar lenses for the consumer product market. Methods: A hyperbolic lens was designed in 3D Computer Aided Design (CAD) software and was then modified with a wavelength specified AR structure. Electromagnetic computer simulation was performed on both the ‘smooth’ and ‘AR structure’ lenses and compared to actual 60 GHz radar measurements of 3D printed polylactic acid (PLA) lenses. Results: The simulation results showed an increase of 10% in signal intensity of the AR structure lens over the smooth lens. Actual measurement showed an 8% increase in signal of the AR structure lens over the smooth lens. Conclusions: Low cost and readily available Fused Filament Fabrication (FFF) 3D printing has been shown to be capable of printing an AR structure coated hyperbolic lens for millimeter wavelength radar applications. These 3D Printed AR structure lenses are effective in improving radar measurements over non-AR structure lenses. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
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| 4. |
- Guarese, Renan, et al.
(författare)
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A proposal for augmented situated visualization towards EMC testing
- 2020
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Ingår i: CEUR Workshop Proceedings. - : CEUR-WS. ; , s. 12-15
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Konferensbidrag (refereegranskat)abstract
- Copyright © 2020 for this paper by its authors.In EMC testing, 3D electromagnetic field data often needs to be visually analysed by an expert in order to detect product defects or unwanted interference between multiple devices. In this sense, the present work proposes the use of data visualization techniques allied to an Augmented Reality user interface to provide information that helps professionals to analyse the same data, however spatially situated where it was first measured. Apart from visualizing it, users may also interact with the data to narrow down their search by switching the attributes being displayed, combining them together, applying filters or changing the formatting in which data is presented. The approaches being proposed in this work will ultimately be tested against each other in comparable 2D and 3D interactive visualizations of the same data in a series of usability assessments with users to validate the solutions. The goal is to ultimately expose whether AR can help users to make more accurate decisions, particularly in EMC related tasks.
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| 5. |
- Hagström, A. L., et al.
(författare)
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An iterative approach to determine the refractive index of 3D printed 60GHz PLA lenses
- 2018
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Ingår i: Proceedings of the 14th Loughborough Antennas and Propagation Conference (LAPC 2018). - Piscataway, N.J. : IEEE. - 9781785619694
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Konferensbidrag (refereegranskat)abstract
- This paper describes an iterative approach to determine quasi-optical properties of standard 3D printer filament material to, in an inexpensive and fast way, construct focusing lenses for millimetre wave systems. Results from three lenses with different focal lengths are shown and discussed. The real part of the permittivity at 60GHz for polylactic acid (PLA) is in this paper determined to be εr=2.74. © 2018 Institution of Engineering and Technology. All rights reserved.
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| 6. |
- Linse, Björn, et al.
(författare)
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A machine learning model for prediction of 30-day primary graft failure after heart transplantation
- 2023
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Ingår i: Heliyon. - London : Elsevier. - 2405-8440. ; 9:3, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- Background: Primary graft failure (PGF) remains the most common cause of short-term mortality after heart transplantation. The main objective was to develop and validate a risk model for prediction of short-term mortality due to PGF after heart transplantation using the ISHLT Heart Transplant Registry. Methods: We developed a non-linear artificial neural networks (ANN) model to evaluate the association between recipient-donor variables and post-transplant PGF. Patients in the ISHLT registry were randomly divided into derivation and an independent internal validation cohort. The primary endpoint was PGF defined as death within 30 days due to Graft failure or Cardiovascular causes or retransplant within 30 days for causes other than rejection. Results: Among 64,964 adult recipients transplanted between 1994 and 2013, mean age was 51 years and 22% were female. The incidence of PGF up to 30 days was 3.7%. The ANN model selected 33 of 77 risk variables as relevant for PGF prediction. The C-index in the test cohort was 0.70 (95% CI: 0.68-0.71). The risk variables which most influenced the PGF were underlying HF diagnosis, ischemia time and sex, while renal function had a lower influence. Conclusion: An ANN model to predict primary graft dysfunction was derived and independently validated. The good discrimination of the ANN model likely results from its flexibility to model potentially non-linear relationships and interactions. Whether this model with improved discrimination can assist in clinical decisions at the time of transplant should be tested. © 2023 The Authors
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| 7. |
- Nilsson, Björn, et al.
(författare)
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A snoozing frequency binary tree protocol
- 2010
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Ingår i: The Third International EURASIP Workshop on RFID Technology, La Manga del Mar Menor, Cartagena, Spain, 6-7 Sept, 2010.
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Konferensbidrag (refereegranskat)abstract
- In this paper we describe and evaluate anenhanced version of an active RFID wake-up and tag IDextraction radio communication protocol. The enhancedprotocol further reduces the transponders’ power consumption(prolonging their battery lifetime). The protocol uses afrequency binary tree method for extracting the identificationnumber of each transponder. This protocol is enhanced byextending it with a framed slotted medium access controlmethod which decreases the number of activations of eachtransponder during tag ID extractions. Using this medium accessmethod, the average number of transponder activations isdecreased with a factor of 2.5 compared to the original protocol.The resulting increase in ID read-out delay is 0.9%, on average.
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| 8. |
- Nilsson, Björn, 1965-, et al.
(författare)
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An active backscatter wake-up and tag identification extraction protocol for low cost and low power active RFID
- 2010
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Ingår i: Proceedings of 2010 IEEE International Conference on RFID-Technology and Applications, RFID-TA 2010. - Piscataway, NJ : IEEE Press. - 9781424466986 - 9781424467006 ; , s. 86-91
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Konferensbidrag (refereegranskat)abstract
- In this paper we present a Radio Frequency Identification (RFID) protocol used to wake up and extract the ID of every tag (or a subset thereof) within reach of a reader in an active backscatter RFID system. We also study the effect on tag energy cost and read-out delay incurred when using the protocol, which is based on a frequency binary tree. Simulations show that, when using the 2.45 GHz ISM band, more than 1500 tags can be read per second.With a population of 1000 tags, the average read-out delay is 319 ms, and the expected lifetime of the RFID tags is estimated to be more than 2.5 years, even in a scenario when they are read out very often.
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| 9. |
- Nilsson, Björn, et al.
(författare)
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An application dependent medium access protocol for active RFID using dynamic tuning of the back-off algorithm
- 2009
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Ingår i: Proceedings of the 2009 IEEE International Conference on RFID (RFID 2009). - Piscataway, N.J. : IEEE Press. - 9781424433377 ; , s. 72-79
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Konferensbidrag (refereegranskat)abstract
- Active Radio Frequency Identification (A-RFID) is a technology where the tags (transponders) carry an on-board energy source for powering the radio, processor circuits, and sensors. Besides offering longer working distance between RFID reader and tag than passive RFID, this also enables the tags to do sensor measurements, calculations and storage even when no RFID-reader is in the vicinity of the tags. In this paper we introduce a medium access data communication protocol which dynamically adjusts its back-off algorithm to best suit the actual active RFID application at hand. Based on a simulation study of the effect on tag energy cost, readout delay, and message throughput incurred by some typical back-off algorithms in a CSMA/CA (Carrier Sense Multiple Access / Collision Avoidance) A-RFID protocol, we conclude that, by dynamic tuning of the initial contention window size and back-off interval coefficient, tag energy consumption and read-out delay can be significantly lowered. We also present specific guidelines on how parameters should be selected under various application constraints (viz. maximum readout delay; and the number of tags passing).
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| 10. |
- Nilsson, Björn, et al.
(författare)
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An Energy and Application Scenario Aware Active RFID Protocol
- 2010
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Ingår i: EURASIP Journal on Wireless Communications and Networking. - New York : Hindawi Publishing Corporation. - 1687-1472 .- 1687-1499. ; 2010:Article ID 432938, s. 15-
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Tidskriftsartikel (refereegranskat)abstract
- The communication protocol used is a key issue in order to make the most of the advantages of active RFID technologies. In this paper we introduce a carrier sense medium access data communication protocol that dynamically adjusts its back-off algorithm to best suit the actual application at hand. Based on a simulation study of the effect on tag energy cost, read-out delay, and message throughput incurred by some typical back-off algorithms in a CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) active RFID protocol, we conclude that by dynamic tuning of the initial contention window size and back-off interval coefficient, tag energy consumption and read-out delay can be significantly lowered. We show that it is possible to decrease the energy consumption per tag payload delivery with more than 10 times, resulting in a 50% increase in tag battery lifetime. We also discuss the advantage of being able to predict the number of tags present at the RFID-reader as well as ways of doing it.
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