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In this study, a new modulation method defined as Ramanujan periodic subspace division multiplexing (RPSDM) is proposed using Ramanujan subspaces. Each subspace contains an integer-valued Ramanujan sum and its circular downshifts as a basis. The proposed RPSDM decomposes the linear time-invariant wireless channels into a Toeplitz stair block diagonal matrices, whereas orthogonal frequency division multiplexing (OFDM) decompose the same into diagonal. Advantages of such structured subspaces representation are studied and compared with an OFDM representation in terms of a peak-average power ratio and bit error rate. Zero-forcing and minimum mean square error detectors are applied to evaluate the performance of OFDM and RPSDM techniques. Finally, the simulation results show that the proposed design (with an additional receiver complexity) outperforms OFDM under both detectors.

MassiveMIMO(MaMI) is one of the fiery topics in 5G wireless communications. It is introduced based on the fact that the channel vectors becomes asymptotically orthogonal (as antenna elements tending to infinity). Convergence of frequency selective channel (quasi static block fading) characteristics in terms of favorable propagation and channel hardening (asymptotically orthogonal) conditions are studied using metrics like Eigenvalue Ratio (EVR), Mean Absolute Deviation (MAD) and Diagonal Dominance (DD). Finally, simulations results for convergence metrics EVR, MAD and DD are compared with its limiting behavior. The effect of time delay spread on the channel convergence is studied based on the condition number of channel matrix.

International audience; The natural flyers flap there wings for its flight. When the wings flap, flow field around the wings would be reoriented and flyers make use of it to sustain its flight. In the present study, particle image velocimetry measurements are used to capture the flow field around the rigid wings attached to a mechanical main flapping mechanism. The experiments are conducted for a kinematic asymmetry flapping of the wing with aspect ratio 1.0 and flapping frequency of 2.0 Hz in quiescent water medium. The dimensions of the wing are 40mm in chord, 40mm in span and thickness of 1.5mm. The Reynolds number is of the order of 10^4. The results revealed the formation of wingtip vortices, flow along the span, added mass and residual flow.

The aim of the present study was to develop sustained release formulation of Verapamil Hydrochloride to maintain constant therapeutic levels of the drug for over 12 hrs. Various grades of HPMC polymers, Guar gum, and Xanthum gum were employed as polymers. Verapamil Hydrochloride dose was fixed as 120 mg. Total weight of the tablet was considered as 400 mg. Polymers were used in the concentration of 60, 120 and 180 mg concentration. All the formulations were passed various physicochemical evaluation parameters and they were found to be within limits. Whereas from the dissolution studies it was evident that the formulation (F6) showed better and desired drug release pattern i.e.,96.10 % in 12 hours containing Guar gum polymer in the concentration of 180mg. It followed zero order release kinetics. For the optimized formulation alcohol effect has been studied by using various concentrations of alcohol in dissolution medium. As the concentration of alcohol increased the sustained action of polymer was decreased. Hence it was concluded that alcohol has significant effect on drug release pattern.

This paper proposes the precoder for Multi User-MassiveMIMO (MU-MaMI) frequency selective broadcast channels with few User Terminals(UTs) having single antenna each. The frequency selective effect of the MaMI channel will be manifested as ISI and IUI. In order to mitigate these interferences and to eliminate the group level decoding of UTs, a precoder is proposed utilizing the block time Channel Impulse Responses (CIRs). This proposed precoder is designed based on the following approaches, Matched Filter(MF), Zero Forcing (ZF), Minimum Mean Square Error (MMSE) and Regularized Channel Inversion (RCI). The performance of these precoders is evaluated using single symbol time (one time symbol) and block time symbols (N time symbols) of each UT. The optimal length N block time symbols and minimum number of Base Station (BS) antennas required for a given N block time and multipath L is evaluated with respect to the Signal-to-Interference Noise Ratio (SINR) asymptotic limits.

3G/4G wireless systems employed multiple antennas at both the transmitter and receiver offered significant gains over single-antenna systems. MassiveMIMO (MM) is one of the 5G technologies, which supports to increase the demand for high speed data, capacity, energy efficiency and spectral efficiency. It is known that space-time multiplexing and/or coding offer attractive means of combating fading and increases the capacity in a multi-antenna communication. In this paper, MM downlink scenario is considered. Performance analysis using conventional precoders like Matched Filter (MF), Zero Forcing (ZF), Regularized Beamforming (RBF) and Minimum Mean Square Error (MMSE) with Singular Value Decomposition (SVD) based balanced equalizer are studied in spatio-temporal environment. Signal to Interference Ratio (SINR) and Bit-Error Rate (BER) are used as performance measures. Monte-Carlo simulations are carried out to compute BER and SINR in MATLAB.

The objectives of this study were to examine the prevalence of assistive technology (AT) use, type of assistance used for each activity of daily living (ADL) limitation, and correlates of AT use among Native Indian aged 55 and older. Data were collected as part of a cross-sectional study of disability with 505 members of a federally recognized tribe using in-person interviewer administered surveys. Participants who reported difficulty with ADLs, including bathing, dressing, eating, transferring, walking, toileting, grooming, and getting outside, were asked about AT use. Other measures were demographics, living arrangements, receipt of personal care, Medicare and Medicaid beneficiary status, number of chronic conditions, lower body function, and personal mastery. Results indicated that 22.3% of participants aged 55 and older and 26.0% aged 65 and older reported AT use. Toileting had the largest percentage of participants who relied on AT only and getting outside had the largest percentage of participants relying on a combination of AT and personal care. Multiple variable logistic regression analysis identified receipt of personal care, having more chronic conditions, and poorer lower body function as significantly associated with higher odds of AT use. The results suggest that there is greater AT use in this sample than in same-aged adults in national samples. This greater use may be reflective of a combination of higher disability rates, cultural factors, and greater access to AT. Clinicians can use this information to identify the activities with which their patients are experiencing the most difficulty and which ones can be addressed with AT versus personal care.