Performance Improvement in Passive Backscatter Based RFID System with Low DCR Modulations

This paper presents application of the low Duty Cycle Ratio (DCR) modulations: isochronous Digital Pulse Position Modulation (DPPM) and anisochronous Digital Pulse Interval Modulation (DPIM) in backscatter based passive RFID communication system. The proposed modulations are compared to commonly used Amplitude Shift Keying (ASK) modulation. Low DCR modulations are customized for data transmission through inductively coupled link between reader and the tag operating at frequency of 13.56 MHz. The RFID system is mathematically formulated and the performances of the tag are evaluated for each modulation. Observed parameters are modulation depth of backscattered signal, voltage-current characteristics of tag rectifier circuit and ripple of rectifier output voltage. The application of proposed low DCR modulation techniques improves the performance of the RFID system by up to 250%

Fade Depth Prediction Using Human Presence for Real Life WSN Deployment

Current problem in real life WSN deployment is determining fade depth in indoor propagation scenario for link power budget analysis using (fade margin parameter). Due to the fact that human presence impacts the performance of wireless networks, this paper proposes a statistical approach for shadow fading prediction using various real life parameters. Considered parameters within this paper include statistically mapped human presence and the number of people through time compared to the received signal strength. This paper proposes an empirical model fade depth prediction model derived from a comprehensive set of measured data in indoor propagation scenario. It is shown that the measured fade depth has high correlations with the number of people in non-line-of-sight condition, giving a solid foundation for the fade depth prediction model. In line-of-sight conditions this correlations is significantly lower. By using the proposed model in real life deployment scenarios of WSNs, the data loss and power consumption can be reduced by the means of intelligently planning and designing Wireless Sensor Network

Marie Hamsun's many truths

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Low-energy electronic structure in Y1-xCaxBa2Cu3O7-y comparison of t ime-resolved optical spectroscopy, NMR, neutron and tunneling data

Time-resolved optical measurements give information on the quasiparticle relaxation dynamics in YBCO, from which the evolution of the gap with doping and temperature can be systematically deduced. In this paper these optical charge-channel `pseudogap' data are compared with the `pseudogap' obtained from the NMR Knight shift Ks, spin polarized neutron scattering (SPNS) and single particle tunneling measurements. A simple energy level diagram is proposed to explain the different `gap' magnitudes observed by different spectroscopies in Y1-xCaxBa2Cu3O7-y, whereby the spin gap Delta_s in NMR and SPNS corresponds to a triplet local pair state, while Delta_p in the charge excitation spectrum corresponds to the pair dissociation energy. At optimum doping and in the overdoped state, an additional T-dependent gap becomes evident, which closes at T_c, suggesting a cross-over to a more conventional BCS-like superconductivity scenario.Comment: 9 pages, 4 figures. Presented in HTS99, Miami, January 9

Structural and functional investigations of Lactobacillus reuteri glucansucrase:... with crystallographic studies on an α-amylase and a prolyl endoprotease from Aspergillus niger

The main topic of this thesis are relatively large extracellular enzymes (~160kDa) named glucansucrases (GS)(EC 2.4.5.1) secreted by lactic acid bacteria. Using sucrose as a substrate they synthesize high molecular mass glucose polymers, called α-glucans. Additionally, in presence of suitable acceptor molecules (e.g. maltose) α-glyco-conjugates are synthesized at the expense of a polymeric product. Due to a vast product specificity of GH70 glucansucrases their products have markedly different properties which make them interesting targets for various industrial applications. Based on amino acid sequence similarity these enzymes (currently 60, CAZy database) have been classified in the Glycoside Hydrolase (GH) family, but no structural information on any of those has been available until now. Lack of structural data severely hampered in-depth understanding of the product specificity determinants of these enzymes