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We experimentally analyze the impact of front-FBG reflectivity in ultra-long Raman laser amplifiers performance, showing Q-factor penalties in excess of 1 dB for FBG reflectivities above 10% in a 30 GBaud DP-QPSK transmission system.
This paper describes the maturation and in-flight testing of a recently developed fault detection (FD) system for a model scale unmanned aerial vehicle (UAV). The FD system design methodology is based on H techniques and exploits an LFT description of the aircraft (A/C) longitudinal dynamics. The maturation of the FD system, presented in the paper, introduces a fault isolation logic to distinguish...
Distributed Raman amplification has different roles to play in combination with of a range of potential solutions to deal with the nonlinear Shannon limit. Here, we will cover issues such as asymmetry optimisation for optical-phase conjugation nonlinear compensation, the combination of optimised distributed amplification with digital nonlinear compensation techniques and the challenges of adopting...
We propose a modification of the nonlinear digital signal processing technique based on the nonlinear inverse synthesis for the systems with distributed Raman amplification. The proposed path-average approach offers 3 dB performance gain, regardless of the signal power profile.
We propose a novel random DFB fiber laser based Raman amplification using bidirectional second-order pumping. This extends the reach of 116 Gb/s DP-QPSK WDM transmission up to 7915 km, compared with other Raman amplification techniques.
This paper addresses the design of robust multiple model adaptive controllers (RMMAC) for linear parameter varying (LPV) systems using bilinear matrix inequalities (BMI). We show a novel method that allows increasing the performance of the RMMAC when the uncertain parameters of the system dynamics are time-varying (TV). We assume that these TV parameters cannot be measured on-line and that the only...
Nyquist-WDM PDM-QPSK transmission over standard SMF-28 fibre with novel distributed URFL amplification is reported for the first time. Transmission over 6157 km in a recirculating loop, and 320 km in an unrepeatered link without a ROPA were demonstrated.
We demonstrate that a combination of Raman laser based amplification and optical phase conjugation enables transmission beyond the nonlinear-Shannon limit. We show nonlinear compensation of 7×114Gbit/s DP-QPSK channels, increasing system reach by 30%.
This paper addresses the problem of Fault Detection and Isolation (FDI) for navigation systems equipped with sensors providing inertial measurements and vector observations. Two strategies are proposed. The first one takes advantage of existing hardware redundancy, providing sufficient conditions for the isolation of faults. The second approach exploits the analytical redundancy between the angular...
The current growth of mobile devices enabled with GPS receptors, cameras, accelerometers, and Internet access offers new opportunities for new mobile ubiquitous multimedia applications. Such applications help local communities to share resources using geo-location, interactive mapping, augmented reality, and several data representations. This paper presents CityEvents, a mobile solution that provides...
Unrepeatered transmission over SMF-28 fibre is investigated using ultra-long Raman fibre laser based amplification. Experiments and simulations demonstrate 8 × 42.7Gb/s transmission up to 320km (67dB) span length using DPSK and ASK modulation with direct detection.
Research on wind turbine Operations & Maintenance (O&M) procedures is critical to the expansion of Wind Energy Conversion systems (WEC). In order to reduce O&M costs and increase the lifespan of the turbine, we study the application of Set-Valued Observers (SVO) to the problem of Fault Detection and Isolation (FDI) of wind turbines, by taking advantage of the recent advances in SVO theory...
This paper addresses the problem of attitude and rate gyro bias estimation using Set-Valued Observers (SVOs). We propose a singularity-free solution that exploits rate gyro measurements and vector observations corrupted by bounded noise providing bounds on the attitude of the rigid body and on the bias of the rate gyros. The sensor readings are fused directly by the SVO, without intermediate attitude...
An optimal Set-Valued Observer (SVO) for attitude estimation that merges rate gyro readings with body frame vectorial observations is proposed. The observer provides singularity-free estimates and considers sensor readings corrupted by bounded (but unknown) measurement noise. The suggested solution is an alternative method to the ones available in the literature, with the guarantee that the state...
This paper introduces the novel concept of using Set-Valued Observers (SVOs) in Fault Detection and Isolation (FDI), for discrete-time linear time-varying systems. The proposed method relies on SVO-based model invalidation to discard models that are not compatible with the input/output data. We argue that there are mainly three significant advantages of using SVOs for FDI, when compared to the most...
This paper proposes a new approach for the selection of a biophysical model describing the haemodynamic response function (HRF) measured in BOLD-fMRI data, based on model falsification techniques. Specifically, the novel method of Multiple Model Set-Valued Observers (MMSVOs) is introduced. The observers consider that the initial state lives in a set, the linear time-varying dynamic system obtained...
The problem of model falsification or model invalidation appears in several areas where we are interested in distinguishing among an eligible set of dynamic systems. In the context of fMRI studies of brain activity, modeling the haemodynamic response function (HRF) is a critical step. The estimation of the dynamic system describing a biophysical model of the HRF may leave much uncertainty on the exact...
This paper proposes a strategy referred to as stability overlay (SO) for linear and nonlinear time-varying plants, that provides input/output stability guarantees for a wide set of adaptive control schemes. We use this methodology to endow multiple-model adaptive control (MMAC) architectures with robust stability properties when the plant to be controlled is uncertain and time-varying. We emphasize...
This paper proposes a multiple-model adaptive control methodology, using set-valued observers (MMAC-SVO) for the identification subsystem, that is able to provide robust stability and performance guarantees for the closed-loop, when the plant, which can be open-loop stable or unstable, has significant parametric uncertainty. We illustrate, with an example, how set-valued observers (SVOs) can be used...
Patient head movement not only inhibits the full potential of high spatial-resolution neurological PET imaging, but it also significantly degrades fully 4D reconstruction when using temporally-extensive basis functions. In this case a single movement in just one of the time frames propagates to impact the reconstruction of all other time frames. Here we propose a motion-compensation strategy through...
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