1,721,048 research outputs found
Design and optimisation of Schottky diodes in CMOS technology with application to passive RFID systems
No full text©2005 COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.In this paper, we present and analyze the most fundamental constraint of RFID systems, power rectification. This issue plays an important role in development of long-range RFID systems. Rectifiers are the key components in power rectifications and efficiency of an RFID system. Therefore this paper is concentrated in investigating this major issue. To tackle this problem a novel Schottky Barrier Diode (SBD) has been proposed. The proposed SBD provides good power conversion rate and switching properties.Behnam Jamali, Peter H. Cole, Damith C. Ranasinghe, and Zheng Zh
Evaluation of wearable sensor tag data segmentation approaches for real time activity classification in elderly
No full textPart of the Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering book series (LNICST, volume 131)The development of human activity monitoring has allowed the creation of multiple applications, among them is the recognition of high falls risk activities of older people for the mitigation of falls occurrences. In this study, we apply a graphical model based classification technique (conditional random field) to evaluate various sliding window based techniques for the real time prediction of activities in older subjects wearing a passive (batteryless) sensor enabled RFID tag. The system achieved maximum overall real time activity prediction accuracy of 95% using a time weighted windowing technique to aggregate contextual information to input sensor data.Roberto Luis Shinmoto Torres, Damith C. Ranasinghe, and Qinfeng Sh
Analysis of a UHF RFID CMOS rectifier structure and input impedance characteristics
No full text© 2006 Society of Photo-Optical Instrumentation EngineersPassive radio frequency identification (RFID) systems deployment efforts are revolutionizing supply chain logistics by providing unprecedented supply chain visibility. The widely used bandwidth of operation in modern systems is the UHF ISM (industrial, scientific, and medical) band. The performance of UHF RFID systems are largely reliant on low power CMOS circuits, efficient power rectification and the ability of RFID label antennas to match to the input impedance of the RFID label IC. This paper examines a new rectifying structure and considers it for its merits in RFID applications while analysing contribution of the rectifying structure to the input impedance of RFID chips as this is an important consideration in impedance matching to an external antenna.Behnam Jamali, Damith C. Ranasinghe, and Peter H. Col
Smart steel: new paradigms for the reuse of steel enabled by digital tracking and modelling
No full textAvailable online 16 September 2014Abstract not availableDavid Ness, John Swift, Damith C. Ranasinghe, Ke Xing, Veronica Soebart
A highly accurate and scalable approach for addressing location uncertainty in asset tracking applications
Full text linkTracking systems that use RFID are increasingly being used for monitoring the movement of goods in supply chains. While these systems are effective, they still have to overcome significant challenges, such as missing reads, to improve their performance further. In this paper, we describe an optimised tracking algorithm to predict the locations of objects in the presence of missed reads using particle filters. To achieve high location accuracy we develop a model that characterises the motion of objects in a supply chain. The model is also adaptable to the changing nature of a business such as flow of goods, path taken by goods through the supply chain, and sales volumes. A scalable tracking algorithm is achieved by an object compression technique, which also leads to a significant improvement in accuracy. The results of a detailed simulation study shows that our object compression technique yields high location accuracy (above 98% at 0.95 read rate) with significant reductions in execution time and memory usage.Rengamathi Sankarkumar, Damith C. Ranasinghe, Thuraiappah Sathya
RFID enabled traceability networks: a survey
No full textThe emergence of radio frequency identification (RFID) technology brings significant social and economic benefits. As a non line of sight technology, RFID provides an effective way to record movements of objects within a networked RFID system formed by a set of distributed and collaborating parties. A trail of such recorded movements is the foundation for enabling traceability applications.While traceability is a critical aspect of majority of RFID applications, realizing traceability for these applications brings many fundamental research and development issues. In this paper, we assess the requirements for developing traceability applications that use networked RFID technology at their core. We propose a set of criteria for analyzing and comparing the current existing techniques including system architectures and data models. We also outline some research opportunities in the design and development of traceability applications.YanboWu, Damith C. Ranasinghe, Quan Z. Sheng, Sherali Zeadally and Jian Y
A2U2: A stream cipher for printed electronics RFID tags
No full textThe design of hardware-oriented ciphers has an increasingly important role to play with emerging ubiquitous and pervasive computing devices, such as low cost passive Radio Frequency Identification (RFID) tags. The importance of such ciphers are further highlighted by novel manufacturing technologies, such as printed ink to develop extremely low cost RFID tags. Such developments bring new challenges, especially in terms of providing security, both to protect privacy as well as to enable applications dependent on security, such as e-tickets. In this paper we present a new stream cipher, A2U2, which uses principles of stream cipher design and approaches from block cipher design. Our lightweight cryptographic primitive has taken into consideration the extremely resource limited environment of printed ink tags, to develop a cipher that can be implemented with less than 300 gates, with the added benefit of high throughput provided by stream ciphers.Mathieu David, Damith C. Ranasinghe and Torben Larse
Exploiting metastability and thermal noise to build a re-configurable hardware random number generator
No full text©2005 COPYRIGHT SPIE--The International Society for Optical Engineering.While pseudo random number generators based on computational complexity are widely used for most of cryptographic applications and probabilistic simulations, the generation of true random numbers based on physical randomness is required to guarantee the advanced security of cryptographic systems. In this paper we present a method to exploit manufacturing variations, metastablity, and thermal noise in integrated circuits to generate random numbers. This metastability based physical random number generator provides a compact and low-power solution which can be fabricated using standard IC manufacturing processes. Test-chips were fabricated in TSMC 0.18um process and experimental results show that the generated random bits pass standard randomness tests successfully. The operation ofthe proposed scheme is robust against environmental changes since it can be re-calibrated to new environmental conditions such as temperature and power supply voltage.Daihyun Lim, Damith C. Ranasinghe, Srinivas Devadas, Behnam Jamali, Derek Abbott, and Peter H. Col
Turn-on circuits based on standard CMOS technology for active RFID labels
No full textThe evolution of RFID Systems has lead to the development of a class hierarchy in which the battery powered labels are a set of higher class labels referred to as active labels. The battery powering active transponders must last for an acceptable time, so the electronics of the label must have very low current consumption in order to prolong the life of the battery. However due to circuit complexity or the desired operating range the electronics may drain the battery more rapidly than desired but use of a turn-on circuit allows the battery to be connected only when communication is needed, thus lengthening the life of the battery. Two solutions available for the development of a turn on circuit use resonance in a label rectification circuit to provide a high sensitivity result. This paper presents the results of experiments conducted to evaluate resonance in a label rectification circuit and the designs of fully integrable turn-on circuits. We have also presented test results showing a successful practical implementation of one of the turn on circuit designs.David Hall, Damith C. Ranasinghe, Behnam Jamali, and Peter H. Col
Antipodal Vivaldi antenna for sum and difference radiation patterns with reduced grating lobes
No full textA new design of an E-plane double-element Vivaldi antenna with sum and difference radiation patterns is presented in this letter. The antenna operates in the frequency range of 2.3–15 GHz (ratio of 6.5:1) with the highest grating lobe level of −10 dB at 15 GHz and competitive gain performance from 6.8 dBi at 2.3 GHz up to 14.7 dBi at 15 GHz. The grating lobes are reduced effectively by decreasing the distance between the two input ports to one wavelength at the highest operating frequency. The active S-parameters of the antenna are improved using modifications of the geometry, including a new method consisting of an increased length of the internal flares, as well as combinations of known methods such as elliptical corrugations on the outer edges, and optimal shaping of inner edges of the antenna. The gain is also improved by the addition of a dielectric lens, which also provides extra space for lengthening the internal flares. The proposed double-element antenna satisfactorily provides the sum and difference radiation patterns when fed by a wide band rat-race coupler. To warrant a near-ideal beam symmetry, the antenna is designed so that the directive radiation pattern occurs when the antenna elements are fed by out-of-phase signals, i.e., when the difference (Δ) port of the coupler is excited.Seyed-Ali Malakooti, Mahdi Moosazadeh, Damith C. Ranasinghe, and Christophe Fumeau
- …
