Node pacing for small optical RAM-buffered packet-switching networks

One of the difficulties with optical packet switched (OPS) networks is buffering optical packets in the network. The only available solution that can currently be used for buffering in the optical domain is using long fiber lines called fiber delay lines (FDLs), which have severe limitations. Moreover, the research on optical RAM presently being done is not expected to achieve a large capacity soon. However, the burstiness of Internet traffic causes high packet drop rates and low utilization in very small buffered OPS networks. We therefore propose a new node-based pacing algorithm for decreasing burstiness. We show that by applying some simple pacing at the edge or core backbone nodes, the performance of very small optical RAM buffered core OPS networks with variable-length packets can be notably increased.     

Concatenation of space‐time block codes and turbo trellis coded modulation (ST‐TTCM) over Rician fading channels with imperfect phase

In this paper, the performance of space time‐turbo trellis coded modulation (ST‐TTCM) is evaluated over Rician and Rayleigh fading channels with imperfect phase. We modify Baum–Welch (BW) algorithm to estimate the fading and phase jitter parameters for multi‐antenna configurations. Thus, we assume that the channel parameters change slower than carrier frequency. We know that, at high data rate transmissions over wireless fading channels, space–time block codes (STBC) provide the maximal possible diversity advantage. Here, the combined effects of the amplitude and the phase of the received signal are considered, each one modelled by Rician and Tikhonov distributions, respectively. We investigate space time‐turbo trellis coded modulation (ST‐TTCM) for 8‐PSK for several Rician factor K and phase distortion factor η. Thus, our results reflect the degradations both due to the effects of the fading on the amplitude and phase noise of the received signal while the channel parameters are estimated by BW algorithm. Copyright © 2004 John Wiley & Sons, Ltd.     

Out of Context: NMDA Receptor Antagonism in the Avian 'Prefrontal Cortex' Impairs Context Processing in a Conditional Discrimination Task.

Processing of context information is implicated in prefrontal functions as response selection or attention. N-methyl-D-aspartate (NMDA) receptors in the mammalian prefrontal cortex (PFC) and in the nidopallium caudolaterale (NCL) of birds, the avian functional equivalent of the PFC, are involved in learning, which also requires processing of context. The authors investigated the role of NMDA receptors in the pigeon (Columba livia) NCL for context processing and response selection in a simultaneous-matching-to-sample task with 2 trial types, requiring either processing of context information, delivered by a conditional stimulus (context dependent), or only recall of a stimulus-response association (fixed response). The competitive NMDA antagonist DL-2-amino-5-phosphonovaleric acid impaired performance only in context-dependent trials. Therefore, NMDA receptors in the avian PFC participate in response selection requiring context processing rather than in response selection per se. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A review: Fibre metal laminates,background, bonding types and applied test methods

During the past decades, increasing demand in aircraft industry for high-performance, lightweight structures have stimulated a strong trend towards the development of refined models for fibre-metal laminates (FMLs). Fibre metal laminates are hybrid composite materials built up from interlacing layers of thin metals and fibre reinforced adhesives. The most commercially available fibre metal laminates (FMLs) are ARALL (Aramid Reinforced Aluminium Laminate), based on aramid fibres, GLARE (Glass Reinforced Aluminium Laminate), based on high strength glass fibres and CARALL (Carbon Reinforced Aluminium Laminate), based on carbon fibres. Taking advantage of the hybrid nature from their two key constituents: metals (mostly aluminium) and fibre-reinforced laminate, these composites offer several advantages such as better damage tolerance to fatigue crack growth and impact damage especially for aircraft applications. Metallic layers and fibre reinforced laminate can be bonded by classical techniques, i.e. mechanically and adhesively. Adhesively bonded fibre metal laminates have been shown to be far more fatigue resistant than equivalent mechanically bonded structures.     

An experimental and three-dimensional numerical study of natural convection heat transfer between two horizontal parallel plates

In this study, experimental and three-dimensional numerical studies were performed to investigate the effects of plate spacing and temperature difference on natural convection between isothermally heated upward-facing lower horizontal plate and externally insulated horizontal upper plate. Air is used as the heat transfer medium. Rayleigh number varied in the 1108–2.339 × 10⁵ range. Several numerical simulations for three-dimensional steady laminar and turbulent flows heat transfer were carried out using a commercial CFD code Fluent 6.2. Results have shown that there is a good agreement between the numerical and present experimental results as well as with available data in literature.     

Determination of ofloxacin in human aqueous humour by high-performance liquid chromatography with fluorescence detection

This unusual pathology has not been described in the medical literature of the last ten years. A 39-year-old patient, affected by unilateral cryptorchidism, on the right side, and congenital inguinal hernia, reached the operating theatre suffering from occlusive intestinal syndrome, due to a clogged hernial sac. This clog was caused by a retracting testicle which in turn stopped the ileal ansa from slipping back in to the peritoneum. Through this case we can underline the excursus of such pathology, which isn't very frequent in the adult but can, nevertheless create a fairly serious pathology, often leading to neoplan.     

Weighted averaging for denoising with overcomplete dictionaries.

We consider the scenario where additive, independent, and identically distributed (i.i.d) noise in an image is removed using an overcomplete set of linear transforms and thresholding. Rather than the standard approach, where one obtains the denoised signal by ad hoc averaging of the denoised estimates provided by denoising with each of the transforms, we formulate the optimal combination as a conditional linear estimation problem and solve it for optimal estimates. Our approach is independent of the utilized transforms and the thresholding scheme, and as we illustrate using oracle-based denoisers, it extends established work by exploiting a separate degree of freedom that is, in general, not reachable using previous techniques. Our derivation of the optimal estimates specifically relies on the assumption that the utilized transforms provide sparse decompositions. At the same time, our work is robust as it does not require any assumptions about image statistics beyond sparsity. Unlike existing work, which tries to devise ever more sophisticated transforms and thresholding algorithms to deal with the myriad types of image singularities, our work uses basic tools to obtain very high performance on singularities by taking better advantage of the sparsity that surrounds them. With well-established transforms, we obtain results that are competitive with state-of-the-art methods.