The Experts below are selected from a list of 376635 Experts worldwide ranked by ideXlab platform
Alan Pak Tao Lau - One of the best experts on this subject based on the ideXlab platform.
-
adaptive chromatic dispersion compensation for coherent communication systems using delay tap Sampling Technique
IEEE Photonics Technology Letters, 2011Co-Authors: Dawei Wang, Alan Pak Tao LauAbstract:A fast and low-complexity adaptive chromatic dispersion (CD) compensation algorithm based on delay-tap Sampling Technique for optical coherent systems is proposed. By generating a delay-tap plot from the signal powers after an adaptive CD equalizer, a parameter can be extracted from the delay-tap plot which can be used to estimate CD accurately. Simulation results for coherent polarization-division-multiplexed (PDM) quaternary phase-shift keying (QPSK) as well as 16-quadrature amplitude modulation (QAM) systems with various pulse shapes demonstrate that high CD estimation accuracies using relatively few data symbols can be achieved in presence of other transmission impairments.
-
osnr monitoring for rz dqpsk systems using half symbol delay tap Sampling Technique
IEEE Photonics Technology Letters, 2010Co-Authors: F N Khan, Alan Pak Tao Lau, P K A WaiAbstract:We propose and experimentally demonstrate an asynchronous half-symbol delay-tap Sampling Technique for in-band optical signal-to-noise ratio (OSNR) monitoring in 38-Gb/s return-to-zero differential quadrature phase-shift-keying systems. The proposed Technique enables simple analytical models for the statistics of a signal pulse which avoids system calibration prior to OSNR monitoring. A monitoring range of 11-23 dB has been demonstrated experimentally. Furthermore, the proposed Technique also extends the range of calibration-based OSNR monitoring Techniques to 5-34 dB.
Kenichi Kitayama - One of the best experts on this subject based on the ideXlab platform.
-
experimental investigation of delay tap Sampling Technique for online monitoring of rz dqpsk signals
IEEE Photonics Technology Letters, 2009Co-Authors: Bartlomiej Kozicki, Akihiro Maruta, Kenichi KitayamaAbstract:We experimentally demonstrate optical performance monitoring of 20-Gb/s return-to-zero differential quadrature phase-shift keying signals using an asynchronous delay-tap Sampling Technique. This method allows online monitoring of accumulated chromatic dispersion in the range from -600 to +600 ps/nm. We also show evaluation of optical signal-to-noise ratio at a level of 6.7 dB and monitor operation at input power of -16 dBm.
Lena Q - One of the best experts on this subject based on the ideXlab platform.
-
high resolution measurement and mapping of tungstate in waters soils and sediments using the low disturbance dgt Sampling Technique
Journal of Hazardous Materials, 2016Co-Authors: Dongxing Guan, Paul N Williams, Jun Luo, Lena QAbstract:Increasing tungsten (W) use for industrial and military applications has resulted in greater W discharge into natural waters, soils and sediments. Risk modeling of W transport and fate in the environment relies on measurement of the release/mobilization flux of W in the bulk media and the interfaces between matrix compartments. Diffusive gradients in thin-films (DGT) is a promising passive Sampling Technique to acquire such information. DGT devices equipped with the newly developed high-resolution binding gels (precipitated zirconia, PZ, or ferrihydrite, PF, gels) or classic/conventional ferrihydrite slurry gel were comprehensively assessed for measuring W in waters. (Ferrihydrite)DGT can measure W at various ionic strengths (0.001-0.5molL(-1) NaNO3) and pH (4-8), while (PZ)DGT can operate across slightly wider environmental conditions. The three DGT configurations gave comparable results for soil W measurement, showing that typically W resupply is relatively poorly sustained. 1D and 2D high-resolution W profiling across sediment-water and hotspot-bulk media interfaces from Lake Taihu were obtained using (PZ)DGT coupled with laser ablation ICP-MS measurement, and the apparent diffusion fluxes across the interfaces were calculated using a numerical model.
P K A Wai - One of the best experts on this subject based on the ideXlab platform.
-
osnr monitoring for rz dqpsk systems using half symbol delay tap Sampling Technique
IEEE Photonics Technology Letters, 2010Co-Authors: F N Khan, Alan Pak Tao Lau, P K A WaiAbstract:We propose and experimentally demonstrate an asynchronous half-symbol delay-tap Sampling Technique for in-band optical signal-to-noise ratio (OSNR) monitoring in 38-Gb/s return-to-zero differential quadrature phase-shift-keying systems. The proposed Technique enables simple analytical models for the statistics of a signal pulse which avoids system calibration prior to OSNR monitoring. A monitoring range of 11-23 dB has been demonstrated experimentally. Furthermore, the proposed Technique also extends the range of calibration-based OSNR monitoring Techniques to 5-34 dB.
Brian J. German - One of the best experts on this subject based on the ideXlab platform.
-
A model-independent adaptive sequential Sampling Technique based on response nonlinearity estimation
Structural and Multidisciplinary Optimization, 2019Co-Authors: Andrea Garbo, Brian J. GermanAbstract:Sequential adaptive Sampling strategies attempt to efficiently and accurately generate surrogate model (SM) training datasets by limiting the number of required function evaluations. Among these Techniques, those that are model independent have attracted attention during the last decade because they do not use a global SM to supervise the Sampling process, thereby relieving the user from the burden of selecting an appropriate SM formulation at the beginning of the Sampling process. In this study, we propose a new model-independent sequential adaptive Sampling Technique called nearest neighbors adaptive Sampling (NNAS). The NNAS formulation introduces a refinement metric based on local linear models that leads to a quasilinear dependency of the algorithm complexity with respect to the number of samples. Additionally, the exploration-refinement balance is achieved by a stochastic Pareto-ranking-based selection criterion that attempts to simultaneously maximize both the exploration and refinement. NNAS is tested on ten two-dimensional and one ten-dimensional analytic functions, a five-dimensional engineering test case based on the XRotor solver (Drela and Youngren 2014 ), and a two-response two-dimensional analytic problem. The results show that NNAS is more computationally efficient than comparable methods without causing a relevant increase in sample requirement.
