Multi-Channel Scheduling for Fast Convergecast in Wireless Sensor Networks

We explore the following fundamental question - how fast can information be collected from a wireless sensor network? We consider a number of design parameters such as, power control, time and frequency scheduling, and routing. There are essentially two factors that hinder efficient data collection - interference and the half-duplex single-transceiver radios. We show that while power control helps in reducing the number of transmission slots to complete a convergecast under a single frequency channel, scheduling transmissions on different frequency channels is more efficient in mitigating the effects of interference (empirically, 6 channels suffice for most 100-node networks). With these observations, we define a receiver-based channel assignment problem, and prove it to be NP-complete on general graphs. We then introduce a greedy channel assignment algorithm that efficiently eliminates interference, and compare its performance with other existing schemes via simulations. Once the interference is completely eliminated, we show that with half-duplex single-transceiver radios the achievable schedule length is lower-bounded by max(2nk − 1,N), where nk is the maximum number of nodes on any subtree and N is the number of nodes in the network. We modify an existing distributed time slot assignment algorithm to achieve this bound when a suitable balanced routing scheme is employed. Through extensive simulations, we demonstrate that convergecast can be completed within up to 50% less time slots, in 100-node networks, using multiple channels as compared to that with single-channel communication. Finally, we also demonstrate further improvements that are possible when the sink is equipped with multiple transceivers or when there are multiple sinks to collect data

High-spin structure and Band Termination in 103^{103}Cd

Excited states of the neutron deficient $^{103}$Cd nucleus have been investigated via the $^{72}$Ge($^{35}$Cl, p3n) reaction at beam energy of 135 MeV by use of in-beam spectroscopic methods. Gamma rays depopulating the excited states were detected using the Gammasphere spectrometer with high-fold $\gamma$-ray coincidences. A quadrupole $\gamma$-ray coincidence analysis ($\gamma^{4}$) has been used to extend the known level scheme. The positive parity levels have been established up to $J = 35/2\hbar$ and $E_{x} = 7.071$ MeV. In addition to the observation of highly-fragmented level scheme belonging to the positive-parity sequences at E$_{x}\sim$ 5 MeV, the termination of a negative-parity sequence connected by $E2$ transitions has been established at $J = 47/2 \hbar$ and $E_{x} = 11.877$ MeV. The experimental results corresponding to both the positive- and negative-parity sequences have been theoretically interpreted in the framework of the core particle coupling model. Evidence is presented for a shape change from collective prolate to non-collective oblate above the $J^{\pi} = 39/2^{-}$ (8011 keV) level and for a smooth termination of the negative-parity band.Comment: 19 pages, 8 figures. Submitted to Phys. Rev.

High-spin structure and Band Termination in 103^{103}Cd

Excited states of the neutron deficient $^{103}$Cd nucleus have been investigated via the $^{72}$Ge($^{35}$Cl, p3n) reaction at beam energy of 135 MeV by use of in-beam spectroscopic methods. Gamma rays depopulating the excited states were detected using the Gammasphere spectrometer with high-fold $\gamma$-ray coincidences. A quadrupole $\gamma$-ray coincidence analysis ($\gamma^{4}$) has been used to extend the known level scheme. The positive parity levels have been established up to $J = 35/2\hbar$ and $E_{x} = 7.071$ MeV. In addition to the observation of highly-fragmented level scheme belonging to the positive-parity sequences at E$_{x}\sim$ 5 MeV, the termination of a negative-parity sequence connected by $E2$ transitions has been established at $J = 47/2 \hbar$ and $E_{x} = 11.877$ MeV. The experimental results corresponding to both the positive- and negative-parity sequences have been theoretically interpreted in the framework of the core particle coupling model. Evidence is presented for a shape change from collective prolate to non-collective oblate above the $J^{\pi} = 39/2^{-}$ (8011 keV) level and for a smooth termination of the negative-parity band.Comment: 19 pages, 8 figures. Submitted to Phys. Rev.

Person localization using sensor information fusion

Nowadays the incredible grow of mobile devices market led to the need for location-aware applications. However, sometimes person location is di cult to obtain, since most of these devices only have a GPS (Global Positioning System) chip to retrieve location. In order to sup- press this limitation and to provide location everywhere (even where a structured environment doesn't exist) a wearable inertial navigation sys- tem is proposed, which is a convenient way to track people in situations where other localization systems fail. The system combines pedestrian dead reckoning with GPS, using widely available, low-cost and low-power hardware components. The system innovation is the information fusion and the use of probabilistic methods to learn persons gait behavior to correct, in real-time, the drift errors given by the sensors.This work is part-funded by ERDF - European Regional Development Fund through the COMPETE Programme (operational programme for competitiveness) and by National Funds through the FCT Fundao para a Cincia e a Tecnologia (Portuguese Foundation for Science and Technology) within project FCOMP-01-0124-FEDER- 028980 (PTDC/EEI-SII/1386/2012). Ricardo also acknowledge FCT for the support of his work through the PhD grant (SFRH/DB/70248/2010)

Synthesis of β-amino alcohols by ring opening of epoxides with amines catalyzed by sulfated tin oxide under mild and solvent-free conditions

One significant and elegant method for creating β-amino alcohols, which are useful intermediates for the synthesis of many different natural and synthetic pharmaceutical compounds, is to open the rings of epoxides with amines. When sulfated tin oxide catalyst (2 mol%) is present, epoxides can open their rings and react with amines to produce corresponding β-amino alcohols in good to high yields under mild circumstances. Under clean circumstances and in a short amount of time, the reaction demonstrated high regioselectivity and functioned well with both aromatic and aliphatic amines at room temperature

Level Structure of 103Ag at high spins

High spin states in $^{103}$Ag were investigated with the Gammasphere array, using the $^{72}$Ge($^{35}$Cl,$2p2n$)$^{103}$Ag reaction at an incident beam energy of 135 MeV. A $\Delta J$=1 sequence with predominantly magnetic transitions and two nearly-degenerate $\Delta J=1$ doublet bands have been observed. The dipole band shows a decreasing trend in the $B(M1)$ strength as function of spin, a well established feature of magnetic bands. The nearly-degenerate band structures satisfy the three experimental signatures of chirality in the nuclei; however microscopic calculations are indicative of a magnetic phenomeno

Systems genetics identifies a role for Cacna2d1 regulation in elevated intraocular pressure and glaucoma susceptibility

Glaucoma is a multi-factorial blinding disease in which genetic factors play an important role. Elevated intraocular pressure is a highly heritable risk factor for primary open angle glaucoma and currently the only target for glaucoma therapy. Our study helps to better understand underlying genetic and molecular mechanisms that regulate intraocular pressure, and identifies a new candidate gene, Cacna2d1, that modulates intraocular pressure and a promising therapeutic, pregabalin, which binds to CACNA2D1 protein and lowers intraocular pressure significantly. Because our study utilizes a genetically diverse population of mice with kno