-
[show abstract]
[hide abstract]
ABSTRACT: We report a case of multiple myeloma associated with light-chain amyloidosis in a 62-year old woman. The patient came to hospital with the main complaint of epigastric pain and gastroscopy showed gastric retention. The patient had been diagnosed with multiple myeloma associated with light-chain amyloidosis after biopsy of the gastric mucosa and bone marrow aspirate. A review of the literature was also performed.
The West Indian medical journal 12/2011; 60(6):681-4. · 0.25 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A highly versatile and programmable bio-potential recording amplifier is presented. The amplifier achieves low-power operation with minimal size by using a fully-differential self-biased operational amplifier and the Miller capacitance technique. The experimental results of recording various biological signals are provided.
Electronics Letters 12/2008; · 0.96 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: It is demonstrated that iteratively decoded variable length space time coded modulation (VL-STCM-ID) schemes are capable of simultaneously providing both coding gain as well as multiplexing and diversity gain. The VL-STCM-ID arrangement is a jointly designed iteratively decoded scheme combining source coding, channel coding, modulation as well as spatial diversity/multiplexing. In this contribution, we analyse the iterative decoding convergence of the VL-STCM-ID scheme using symbol-based three-dimensional EXIT charts. The performance of the VL-STCM-ID scheme is shown to be about 14.6 dB better than that of the fixed length STCM (FL-STCM) benchmarker at a source symbol error ratio of 10<sup>-4</sup>, when communicating over uncorrelated Rayleigh fading channels. The performance of the VL-STCM-ID scheme when communicating over correlated Rayleigh fading channels using imperfect channel state information is also studied.
Communications, 2007. ICC '07. IEEE International Conference on; 07/2007
-
[show abstract]
[hide abstract]
ABSTRACT: The development of high current-density cathodes employing scandia-doped tungsten powders is reviewed in this paper. A matrix with a submicrometer microstructure characterized by uniformly distributed nanometer particles of scandia is believed to play a dominant role in the improved emission capability of these cathodes. Space-charge-limited current densities of over 30 A/cm<sup>2</sup> at 850 degC<sub>b</sub> have been repeatedly obtained for many runs of cathodes fabricated from the different batches of scandia-doped tungsten powders. A lifetime of over 10000 h at 950-degC<sub>b</sub> 2-A/cm<sup>2</sup> dc loading in a test diode has been achieved. Periodic high current-density pulse testing was also carried out during the test. The performance for both the dc and pulsed current densities remained stable. When tested at Stanford Linear Accelerator Center in a cathode life test vehicle with a Pierce gun configuration, the cathode operated for 500 h at 1170 degC <sub>b</sub>, with a pulsed loading of 100 A/cm<sup>2</sup> and with less than 5% degradation in current density. The outstanding performance of these cathodes is attributed to a surface multilayer of Ba-Sc-O of about 100-nm thickness that uniformly covers the W grains with nanometer-size particles distributed on the growth steps. The layer is formed after proper activation by diffusion of free or ionic Sc together with Ba and O from the interior of the cathode to its surface. This highly mobile, free, or ionic Sc is liberated from constituents produced during impregnation and activation by reactions between the matrix materials and impregnants
IEEE Transactions on Electron Devices 06/2007; · 2.32 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In this contribution projection approximation subspace tracking using deflation (PASTD) is investigated in the context of MIMO transmit preprocessing systems by exploiting the specific property of time division duplexing (TDD) techniques that the uplink and downlink channels are similar, since they both use the same carrier frequency. Hence the channel estimated from the received signal can also be used for transmit preprocessing. More explicitly, based on the received signal, the PASTD algorithm is used for tracking both the left and the right singular vectors of the MIMO channel matrix, which are required by eigenmode transmissions, instead of periodically reestimating the MIMO channel matrix and performing the singular value decomposition (SVD), which would impose a high computational complexity. A specific deficiency of the family of subspace tracking algorithms is their phase ambiguity imposed by the non-unique nature of the SVD, which is resolved in this treatise by employing differential encoding. The efficiency of the proposed subspace tracking scheme is demonstrated by our performance results, indicating that the advocated technique preforms within 1 dB from the BER curve of the perfect channel estimation aided benchmarker.
Vehicular Technology Conference, 2007. VTC2007-Spring. IEEE 65th; 05/2007
-
S. Sankaran,
S. Arai,
R. Augur,
M. Beck,
G. Biery,
T. Bolom,
G. Bonilla,
O. Bravo,
K. Chanda,
M. Chae, [......],
T. Spooner,
T. Standaert,
J. Sucharitaves,
C. Tian,
H. Wendt,
J. Werking,
J. Widodo,
L. Wiggins,
R. Wisnieff,
T. Ivers
[show abstract]
[hide abstract]
ABSTRACT: A high performance 45nm BEOL technology with proven reliability is presented. This BEOL has a hierarchical architecture with up to 10 wiring levels with 5 in PECVD SiCOH (k=3.0), and 3 in a newly-developed advanced PECVD ultralow-k (ULK) porous SiCOH (k=2.4). Led by extensive circuit performance estimates, the detrimental impact of scaling on BEOL parasitics was overcome by strategic introduction of ULK at 2times wiring levels, and increased 1times wire aspect ratios in low-k, both done without compromising reliability. This design point maximizes system performance without adding significant risk, cost or complexity. The new ULK SiCOH film offers superior integration performance and mechanical properties at the expected k-value. The dual damascene scheme (non-poisoning, homogeneous ILD, no trench etch-stop or CMP polish-stop layers) was extended from prior generations for all wiring levels. Reliability of the 45 nm-scaled Cu wiring in both low-k and ULK levels are proven to meet the criteria of prior generations. Fundamental solutions are implemented which enable successful ULK chip-package interaction (CPI) reliability, including in the most aggressive organic flip-chip FCPBGA packages. This represents the first successful implementation of Cu/ULK BEOL to meet technology reliability qualification criteria
Electron Devices Meeting, 2006. IEDM '06. International; 01/2007
-
[show abstract]
[hide abstract]
ABSTRACT: This paper investigates a new approach for stator winding insulation diagnosis. Unlike conventional methods such as insulation resistance tests or partial discharge monitoring, this approach is based on the effective use of parametric modelling and identification. The guiding principle consists in modelling the high-frequency input-output behavior of the winding ground-wall insulation system. The originality and the difficulty of our work are to find the best tradeoff between simplicity for system identifiability and complexity for diagnosis abilities. More specifically, we try to distinguish between winding pollution (moisture, coal or metallic dust) and insulation material ageing because the maintenance procedures and their induced costs are very different. Experiments have been carried out in order to appreciate the feasibility of this approach. A high voltage MOSFET pulse generator with ultra fast rise time has been specially designed. It allows to apply an input excitation covering the wide frequency range required for the ground-wall insulation system identification. In order to isolate numerous phenomena which could be mixed together in the whole machine, the experiments first deal with one bar and one coil taken from a 5 kV induction machine. Diagnosis model parameters are identified by means of advanced identification algorithms with different moisture contents. The first results are promising
IEEE Industrial Electronics, IECON 2006 - 32nd Annual Conference on; 12/2006
-
[show abstract]
[hide abstract]
ABSTRACT: BoomSAR system is a SAR device embarked in the basket of a boom lift, which provides a cheap and flexible platform to evaluate the performance of radar system and signal processing algorithm, especially for foliage penetration imaging. The common BoomSAR system moves along a straight line to produce the synthetic aperture effect. This paper introduces a special operation mode of BoomSAR, where the rotation of boomlift arm is adopted to form a curving synthetic aperture trajectory. The experimental results show the feasibility and effectiveness of this special operation mode in application to foliage penetration imaging and the theoretical resolution performance is achieved
Radar, 2006. CIE '06. International Conference on; 11/2006
-
[show abstract]
[hide abstract]
ABSTRACT: Because of current strong globalization trend, manufacturers are more willing to go to regional or globalism by setting-up plants closer to customers in order to reduce operation costs. Accordingly, mid-term capacity planning paradigm has shifted from algorithm-based solutions for single production site to collaboration-oriented planning in multiple production sites. This paper presents an agent-based multi-site capacity planning framework for autonomous plants within an organization by exploiting the features of agents (autonomy, social ability, re-, and pro-activeness). The creation of a "community of practice", where explicit knowledge in knowledge base and tacit knowledge are shared among systems and people, will facilitate the knowledge flow across department walls and plants' boundaries, supporting the generation of "global optimal" capacity plans. This paper also demonstrates quantitative benefits in reduction of tardy jobs in multi-site capacity planning through a simulation.
Industrial Informatics, 2006 IEEE International Conference on; 09/2006
-
[show abstract]
[hide abstract]
ABSTRACT: STBC-encoded cooperative transmission is studied in a typical wireless sensor network communication protocol LEACH (low-energy adaptive clustering hierarchy). The effect of imperfect synchronization among cooperative sensors is studied and a new STBC encoding scheme is proposed when asynchronism becomes significant Cooperation overhead and energy efficiency are analyzed. The analysis and simulation results demonstrate that cooperative transmission is promising in wireless sensor networks in spite of the increased cost of synchronization and circuitry energy consumption.
Signals, Systems and Computers, 2004. Conference Record of the Thirty-Eighth Asilomar Conference on; 12/2004
-
[show abstract]
[hide abstract]
ABSTRACT: A new RF photocathode electron gun and beamline have been built for the study of electron beam driven wakefield acceleration. The one and a half cell L-band gun operates with an electric field on the cathode surface of 80 MV/m, and generates electron bunches with tens of nanocoulombs of charge and rms bunch lengths of a few picoseconds. The beam diagnostics include a Cherenkov radiator and streak-camera for bunch length measurements, YAG screens for beam profile, integrating charge transformers (ICTs) for bunch charge, an energy spectrometer, and a pepper-pot plate for measurement of the transverse emittance. Measurements of the beam properties at various bunch charges are presented.
Particle Accelerator Conference, 2003. PAC 2003. Proceedings of the; 06/2003
-
[show abstract]
[hide abstract]
ABSTRACT: In this paper a spectrum of optical device at telecommunication wavelengths such as fixed or tunable filters, beam combiners and pump stabilizers have been demonstrated based on volume Bragg grating technology. The technology has been benefited from advancement in the materials and recording techniques developed for fibre Bragg grating and holography. The integration of many filtering functions on the same chip and the compatibility with MEMS switching mirrors make VBGs very attractive for a wide range of tunable components.
Optical Fiber Communications Conference, 2003. OFC 2003; 04/2003
-
[show abstract]
[hide abstract]
ABSTRACT: We report on the performance of carbon-doped heterojunction
bipolar transistors (HBTs) bias stressed at elevated temperatures. We
have determined that in devices without a thin passivating layer of
AlGaAs covering the extrinsic base, a tunneling-recombination current
that increases in magnitude with the duration of the stress is
generated. This current is seen in both the collector and the base at
cryogenic temperatures. The variation of this current with temperature
is primarily due to carrier freeze-out in the AlGaAs emitter. We
hypothesize that this conduction mechanism is related to the generation
of midgap traps in the base layer as a result of electron-hole
recombination events
Electron Devices Meeting, 1994. IEDM '94. Technical Digest., International; 01/1995
-
[show abstract]
[hide abstract]
ABSTRACT: The error performance of differential detection of phase shift
keyed (PSK) signals in a 2-ray frequency selective Rayleigh fading
channel with additive white Gaussian noise is discussed. Unlike in a
one-ray or flat fading channel, there exists an irreducible error floor
even with static fading. In the worst case, this error floor is actually
proportional to the inverse power split ratio among the two arrival
rays. The results presented indicate that at a received signal-to-noise
ratio of 25 dB and a target bit error rate of not more than 10<sup>-2
</sup> (speech application), uncoded differential PSK (DPSK) will work
well even under equal power split, provided that the relative
propagation delay in two arrival rays does not exist one-fifth of a
symbol duration. For channels with larger relative delays. DPSK will
fail to provide the desired bit error rate, unless the signal power is
increased, or more importantly, the channels exhibit highly asymmetrical
power split. Simulation results for coded binary PSK with differential
detection are also included
Global Telecommunications Conference, 1992. Conference Record., GLOBECOM '92. Communication for Global Users., IEEE; 01/1993
-
[show abstract]
[hide abstract]
ABSTRACT: A high resolution parallel algorithm is proposed for estimating
the spectrum of a narrow-band signal from a short data record. The
algorithm is based on combining the nonparametric and parametric
approaches, where the nonparametric approach is used to decompose the
measurement data into an orthogonal set of components, and the
parametric approach is used to estimate the model of these components in
parallel. A fast Fourier transform (FFT) is used to decompose the
signal. A singular value decomposition (SVD)-based linear predictive
coding algorithm (LPCA) is used to obtain an autoregressive moving
average (ARMA) model of the signal components. The FFT of the signal
components is translated to the low-frequency region, and their inverse
FFTs are decimated before estimating the ARMA model so as to separate
the closely-spaced modes. The spectra of the estimates are translated
back to their original location. The proposed algorithm is evaluated
using simulation
Decision and Control, 1992., Proceedings of the 31st IEEE Conference on; 02/1992
-
[show abstract]
[hide abstract]
ABSTRACT: The authors describe sufficient conditions, extending earlier work
by J. Kurzweil and J. Jarnik (Results in Mathematics, vol.14, p.125-137,
(1988)), for a sequence of inputs to be such that, for every
m -tuple of smooth vector fields, the trajectories of the time
derivative of x ( t ) converge to those of an extended
system, where the new vector fields are Lie brackets of the original
m -tuples. Using these conditions, the inverse problem is
solved, wherein given a trajectory γ of the extended system, one
must find trajectories of the original system that converge to γ.
This is done by means of a universal construction that only involves
knowledge of the coefficients of the extended system. These results can
be applied to solve the problem of approximate tracking for a
controllable system without drift
Decision and Control, 1991., Proceedings of the 30th IEEE Conference on; 01/1992
-
[show abstract]
[hide abstract]
ABSTRACT: The method of multiple trellis-coded modulation is applied to
continuous phase modulation (CPM). Double trellis-coded quaternary CPM
schemes using convolutional codes with an effective rate of 2/4 are
considered. Tables of optimum codes and minimum Euclidean distances are
given for several frequency impulses and ratios of
trellis-branches-per-symbol-interval, which have to be processed by a
Viterbi-decoder. The results are clearly superior to single
trellis-coded schemes with 1/2-rate codes. These improvements are
accomplished by a proper selection of double-channel symbols. This
method also offers improved receiver implementation properties. For a
further reduction of complexity, a modified decision-feedback-sequence
estimation is proposed
Communications, 1988. ICC '88. Digital Technology - Spanning the Universe. Conference Record., IEEE International Conference on; 07/1988
-
[show abstract]
[hide abstract]
ABSTRACT: A fully optical version of the oblique evaporation technique through undercut photoresist stencils developed by Dolan is used to fabricate planar variable-thickness S-N-S microbridges. An experimental study of the static and dynamic behaviour of Pb-Cu-Pb devices is reported. I c R N -products are found in good agreement with the Likharev theory and its modifications. In the shortest microbridges we find I c R N - values of the order of the limiting value 2Δ pb (O)/e. The I-V curves show hysteresis only at the lowest temperatures of our experiments and exhibit sharp quantum steps when the samples are exposed to microwave radiation.
IEEE Transactions on Magnetics 06/1983; · 1.36 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A systematic and unified scheme is proposed to monitor the performance of control systems and to tune the controller automatically so as to minimize the integral squared-error measure. The features which are necessary for monitoring and controller tuning are identified to be a feature vector and an influence matrix, and a robust and reliable estimation scheme is proposed to extract these features from the raw measurement data. The feature vector is formed from the coefficients of the sensitivity function (closed-loop transfer function relating the reference input to the tracking error signal). The influence matrix is the Jacobian matrix of the feature vector with respect to the controller parameters. The feature vector and the influence matrix are estimated from a short-time record of the tracking error signal when the reference input is excited by a known input and controller parameters are perturbed one at a time. The proposed tuning scheme is evaluated on a simulated two-area interconnected power system.
Electric Power Systems Research.
