Kittaneh, Omar A.; Shehata, Mohamed; Majid, M. A.(2018 15th Learning and Technology Conference (L&T), Institute of Electrical and Electronics Engineers (IEEE), 2018-05-31)[Conference Paper]
Beyond energy saving, LED connected lighting systems allows for real-time data streaming, generating intelligence and creation of intelligent buildings systems. Lifetime experiments is crucial for such a connected system, as early termination would lead to big errors in estimating the lifetime model parameters, and late termination would waste time and cost. In this paper sup-entropy is applied in quantifying the amount of information in censored solid state lighting (SSL) luminaire experimental data that has Weibull distribution with respect to complete data. We use a quantity called efficiency of the censored sample as an indicator of the quality and goodness of the censoring scheme. This allowed us to determine the suitable termination time of the experiment subject to a desired efficiency. An intensive simulation study is conducted to validate our procedure.
Wang, Tengfei; Cheng, Jiubing(SEG Technical Program Expanded Abstracts 2017, Society of Exploration Geophysicists, 2017-08-17)[Conference Paper]
Elastic reflection waveform inversion (ERWI) utilize the reflections to update the low and intermediate wavenumbers in the deeper part of model. However, ERWI suffers from the cycle-skipping problem due to the objective function of waveform residual. Since traveltime information relates to the background model more linearly, we use the traveltime residuals as objective function to update background velocity model using wave equation reflected traveltime inversion (WERTI). The reflection kernel analysis shows that mode decomposition can suppress the artifacts in gradient calculation. We design a two-step inversion strategy, in which PP reflections are firstly used to invert P wave velocity (Vp), followed by S wave velocity (Vs) inversion with PS reflections. P/S separation of multi-component seismograms and spatial wave mode decomposition can reduce the nonlinearity of inversion effectively by selecting suitable P or S wave subsets for hierarchical inversion. Numerical example of Sigsbee2A model validates the effectiveness of the algorithms and strategies for elastic WERTI (E-WERTI).
Halbawi, Wael; Duursma, Iwan; Dau, Hoang; Hassibi, Babak(2017 IEEE International Symposium on Information Theory (ISIT), Institute of Electrical and Electronics Engineers (IEEE), 2017-08-29)[Conference Paper]
We construct balanced and sparse generator matrices for Tamo and Barg's Locally Recoverable Codes (LRCs). More specifically, for a cyclic Tamo-Barg code of length n, dimension k and locality r, we show how to deterministically construct a generator matrix where the number of nonzeros in any two columns differs by at most one, and where the weight of every row is d + r - 1, where d is the minimum distance of the code. Since LRCs are designed mainly for distributed storage systems, the results presented in this work provide a computationally balanced and efficient encoding scheme for these codes. The balanced property ensures that the computational effort exerted by any storage node is essentially the same, whilst the sparse property ensures that this effort is minimal. The work presented in this paper extends a similar result previously established for Reed-Solomon (RS) codes, where it is now known that any cyclic RS code possesses a generator matrix that is balanced as described, but is sparsest, meaning that each row has d nonzeros.
Lapenna, Pasquale E.; Lamioni, Rachele; Ciottoli, Pietro Paolo; Creta, Francesco(2018 AIAA Aerospace Sciences Meeting, American Institute of Aeronautics and Astronautics (AIAA), 2018-01-07)[Conference Paper]
A numerical framework for the direct simulation, in the low-Mach number limit, of reacting and non-reacting transcritical flows is presented. The key feature are an efficient and detailed representation of the real fluid properties and an high-order spatial discretization. The latter is of fundamental importance to correctly resolve the largely non-linear behavior of the fluid in the proximity of the pseudo-boiling. The validity of the low-Mach number assumptions is assessed for a previously developed non-reacting DNS database of transcritical and supercritical mixing. Fully resolved DNS data employing high-fidelity thermodynamical models are also used to investigate the spectral characteristic as well as the differences between transcritical and supercritical jets.
Ghalib, Asim; Hussain, Rifaqat; Sharawi, Mohammad S.(2017 11th European Conference on Antennas and Propagation (EUCAP), Institute of Electrical and Electronics Engineers (IEEE), 2017-06-07)[Conference Paper]
In this paper, a frequency reconfigurable multiple-input-multiple-output (MIMO) slot antenna is presented. The proposed design is low profile and compact with wide tunability range, covering several well-known frequency bands from 1800 MHz to 2450 MHz. The frequency reconfigurability is achieved by loading the annular slot with varactor diodes. The antenna system is also analyzed for MIMO performance metrics. Moreover, the effect of circular slot antenna on the chassis modes is also investigated using the theory of characteristic modes (TCM). The physical principle behind frequency reconfigurability is also investigated using TCM analysis. An interesting finding is observed using varactor diodes for frequency reconfigurability, that is the reactive impedance loading does not alter the modal significance (MS) plots but only aid in the input impedance matching at different frequency bands.
Alanwar, Amr; Anwar, Fatima M.; Zhang, Yi-Fan; Pearson, Justin; Hespanha, Joao; Srivastava, Mani B.(2017 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control, and Communication (ISPCS), Institute of Electrical and Electronics Engineers (IEEE), 2017-10-05)[Conference Paper]
The Beaglebone Black single-board computer is well-suited for real-time embedded applications because its system-on-a-chip contains two
Gu, Mingming; Satija, Aman; Lucht, Robert P.(2018 AIAA Aerospace Sciences Meeting, American Institute of Aeronautics and Astronautics (AIAA), 2018-01-07)[Conference Paper]
The effects of moderate levels of chirp in the pump and Stokes pulses on chirped-probe-pulse femtosecond coherent anti-Stokes Raman scattering (CPP fs CARS) were investigated. The frequency chirp in the pump and Stokes pulses was introduced by placing SF11 glass disks with thicknesses of 10 mm or 20 mm in the optical path for these beams. The magnitude of the chirp in the probe beam was much greater and was induced by placing a 30-cm rod of SF10 glass in the beam path. The temperature measurements were performed in hydrogen/air non-premixed flames stabilized on a Hencken burner at equivalence ratios of 0.3, 0.5, 0.7, and 1.0. We performed measurements with no disks in pump and Stokes beam paths, and then with disks of 10 mm and 20 mm placed in both beam paths. The spectrum of the nonresonant background four-wave mixing signal narrowed considerably with increasing pump and Stokes chirp, while the resonant CARS signal was relatively unaffected. Consequently, the interference of the nonresonant background with the resonant CARS signal in the frequency-spread dephasing region of the spectrum was minimized. The increased rate of decay of the resonant CARS signal with increasing temperature was thus readily apparent. We have started to analyze the CPP fs CARS thermometry data and initial results indicate improved accuracy and precision are obtained due to moderate chirp in the pump and Stokes laser pulses.
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