A robust orthogonal adaptive approach to SISO deconvolution

This paper formulates in a common framework some results from the fields of robust filtering, function approximation with orthogonal basis, and adaptive filtering, and applies them for the design of a general deconvolution processor for SISO systems. The processor is designed to be robust to small parametric uncertainties in the system model, with a partially adaptive orthogonal structure. A simple gradient type of adaptive algorithm is applied to update the coefficients that linearly combine the fixed robust basis functions used to represent the deconvolver. The advantages of the design are inherited from the mentioned fields: low sensitivity to parameter uncertainty in the system model, good numerical and structural behaviour, and the capability of tracking changes in the systems dynamics. The linear equalization of a simple ADSL channel model is presented as an example including comparisons between the optimal nominal, adaptive FIR, and the proposed design.Facultad de IngenieríaComisión de Investigaciones Científicas de la provincia de Buenos Aire

A robust orthogonal adaptive approach to SISO deconvolution

This paper formulates in a common framework some results from the fields of robust filtering, function approximation with orthogonal basis, and adaptive filtering, and applies them for the design of a general deconvolution processor for SISO systems. The processor is designed to be robust to small parametric uncertainties in the system model, with a partially adaptive orthogonal structure. A simple gradient type of adaptive algorithm is applied to update the coefficients that linearly combine the fixed robust basis functions used to represent the deconvolver. The advantages of the design are inherited from the mentioned fields: low sensitivity to parameter uncertainty in the system model, good numerical and structural behaviour, and the capability of tracking changes in the systems dynamics. The linear equalization of a simple ADSL channel model is presented as an example including comparisons between the optimal nominal, adaptive FIR, and the proposed design.Facultad de IngenieríaComisión de Investigaciones Científicas de la provincia de Buenos Aire

Analysis of the CFO Successive Interference Cancellation for the OFDMA Uplink

The uplink of orthogonal frequency division multiple access or single-carrier frequency division multiple access suffers multiple access interference when carrier frequency offset (CFO) is not properly estimated and compensated. In particular, multicarrier uplink CFO compensation is highly complex due to the multiuser context. Successive interference cancellation algorithms are effectively employed to compensate for the CFO, where the interference produced by each user is handled sequentially through a series of iterations. The main contribution of this work is the analysis of the CFO compensation performance of efficient successive cancellation algorithms. We study the mean square symbol error, and derive a useful upper-bound of the compensation technique performance at convergence. This result extends the general convergence results for the space-alternating generalized expectation-maximization algorithm in the CFO compensation scenario. Finally, we validate the analysis with numerical simulations.Facultad de IngenieríaInstituto de Investigaciones en Electrónica, Control y Procesamiento de Señale

Deep-water sediment transport patterns and basin floor topography in early rift basins: Plio-Pleistocene syn-rift of the Corinth Rift, Greece

Our current understanding on sedimentary deep-water environments is mainly built of information obtained from tectonic settings such as passive margins and foreland basins. More observations from extensional settings are particularly needed in order to better constrain the role of active tectonics in controlling sediment pathways, depositional style and stratigraphic stacking patterns. This study focuses on the evolution of a Plio-Pleistocene deep-water sedimentary system (Rethi-Dendro Formation) and its relation to structural activity in the Amphithea fault block in the Corinth Rift, Greece. The Corinth Rift is an active extensional basin in the early stages of rift evolution, providing perfect opportunities for the study of early deep-water syn-rift deposits that are usually eroded from the rift shoulders due to erosion in mature basins like the Red Sea, North Sea and the Atlantic rifted margin. The depocentre is located at the exit of a structurally controlled sediment fairway, approximately 15 km from its main sediment source and 12 km basinwards from the basin margin coastline. Fieldwork, augmented by digital outcrop techniques (LiDAR and photogrammetry) and clast-count compositional analysis allowed identification of 16 stratigraphic units that are grouped into six types of depositional elements: A—mudstone-dominated sheets, B—conglomerate-dominated lobes, C—conglomerate channel belts and sandstone sheets, D—sandstone channel belts, E—sandstone-dominated broad shallow lobes, F—sandstone-dominated sheets with broad shallow channels. The formation represents an axial system sourced by a hinterland-fed Mavro delta, with minor contributions from a transverse system of conglomerate-dominated lobes sourced from intrabasinal highs. The results of clast compositional analysis enable precise attribution for the different sediment sources to the deep-water system and their link to other stratigraphic units in the area. Structures in the Amphithea fault block played a major role in controlling the location and orientation of sedimentary systems by modifying basin-floor gradients due to a combination of hangingwall tilt, displacement of faults internal to the depocentre and folding on top of blind growing faults. Fault activity also promoted large-scale subaqueous landslides and eventual uplift of the whole fault block. © 2019 The Authors. Basin Research published by International Association of edimentologists and European Association of Geoscientists and Engineers and John Wiley & Sons Lt

Myths of neoconservatism: George W. Bush's "neo-conservative" foreign policy revisited

The objective of this article is to refute the popular and influential view that neoconservatism is the driving force behind US foreign policy under George W. Bush. In fact, neoconservatism — properly understood — has been a marginal influence on a foreign policy, which has been characterized primarily by a different kind of conservative ideology. In order to demonstrate this, the article firstly seeks clearly to define contemporary neoconservatism in the foreign policy context; it then goes on to examine the Bush foreign policy and its key elements. What all this reveals is that US policy has been more driven by nationalist impulses than neoconservative ones. Indeed, those like Stefan Halper and Jonathan Clarke who argue that neoconservatism has been the key component shaping the Bush outlook, not only exaggerate the influence of one particular ideology but underestimate the importance of other key factors determining American policy since 2001