Cyclic redundancy check‐based detection algorithms for automatic identification system signals received by satellite

This paper addresses the problem of demodulating signals transmitted in the automatic identification system. The main characteristics of such signals consist of two points: (i) they are modulated using a trellis‐coded modulation, more precisely a Gaussian minimum shift keying modulation; and (ii) they are submitted to a bit stuffing procedure, which makes more difficult the detection of the transmitted information bits. This paper presents several demodulation algorithms developed in different contexts: mono‐user and multi‐user transmissions, and known/unknown phase shift. The proposed receiver uses the cyclic redundancy check (CRC) present in the automatic identification system signals for error correction and not for error detection only. By using this CRC, a particular Viterbi algorithm, on the basis of a so‐called extended trellis, is developed. This trellis is defined by extended states composed of a trellis code state and a CRC state. Moreover, specific conditional transitions are defined to take into account the possible presence of stuffing bits. The algorithms proposed in the multi‐user scenario present a small increase of computation complexity with respect to the mono‐user algorithms. Some performance results are presented for several scenarios in the context of the automatic identification system and compared with those of existing techniques developed in similar scenarios. Copyright © 2013 John Wiley & Sons, Ltd.     

Controlling the structure of a porous polymer by coupling supercritical CO2 and single screw extrusion process

A study on the extrusion of Eudragit E100 was carried out using supercritical carbon dioxide (scCO₂) as plasticizer and foaming agent. ScCO₂ modifies the rheological properties of the material in the barrel of the extruder and acts as a blowing agent during the relaxation when flowing through the die. For experiments, a single‐screw extruder was modified to be able to inject scCO₂ within the extruded material. The aim is to determine a correlation between operating conditions and foam structure. The effect of three parameters was studied: the temperature in the die and in the metering zone, the screw speed, and the volumetric flow rate of CO₂. An increase in temperature enhances the expansion rate and the average pore diameter and appears to be the most significant parameter. The effect of CO₂ concentration is significant at small concentrations only: the higher the CO₂ concentration, the lower the pore density and the higher both the pore diameter and the expansion rate. The effect of the screw speed is tricky because a variation of this speed involves a decrease of CO₂ weight ratio. This study shows that the structure of the extrudates does not evolve with a coupling of screw speed increase and a subsequent CO₂ weight ratio decrease. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Functional Nanogels as Platforms for Imparting Antibacterial,Antibiofilm, and Antiadhesion Activities to Stainless Steel

In this work, long‐term antibacterial, antiadhesion, and antibiofilm activities are afforded to industrial stainless steel surfaces following a green and bio‐inspired strategy. Starting from catechol bearing synthetic polymers, the film cross‐linking and the grafting of active (bio)molecules are possible under environmentally friendly conditions (in aqueous media and at room temperature). A bio‐inspired polyelectrolyte, a polycation‐bearing catechol, is used as the film‐anchoring polymer while a poly(methacrylamide)‐bearing quinone groups serves as the cross‐linking agent in combination with a polymer bearing primary amine groups. The amine/quinone reaction is exploited to prepare stable solutions of nanogels in water at room temperature that can be easily deposited to stainless steel. This coating provides quinone‐functionalized surfaces that are then used to covalently anchor active (bio)molecules (antibiofilm enzyme and antiadhesion polymer) through thiol/quinone reactions.     

A UMTS-FDD Cell Search Engine

This paper addresses the initial acquisition for the UMTS-FDD W-CDMA standard. It presents an innovative cell searcher design optimized for acquisition speed and low power consumption [1]. The proposed architecture relies on a memory-based digital matched filter with permuted processing order. We can reconfigure the same filtering hardware to process the three steps of the UMTS-FDD initial cell search, due to a thorough HW/SW codesign, in particular the implementation of an innovative algorithm for the second step of the initial acquisition. The searcher can also perform other functions such as initial delay profiling, neighboring cell search and idle-mode timing alignment, which are typically carried out, at least partially, by the Rake receiver. These additional capabilities allow for further system-level power savings because they avoid activating the Rake and reduce the RF front-end working time to a bare minimum.     

Severe congenital hypopituitarism with low prolactin levels and age-dependent anterior pituitary hypoplasia: a clue to a PIT-1 mutation

Neutrophil phagocytosis of fluorescently labelled Staphylococcus aureus and oxidative burst by the neutrophils were assessed by flow cytometry in 22 patients with recurrent furunculosis and in 17 controls. Phagocytosis and oxidative burst were not found to be significantly different between the patients and controls. Low serum iron concentrations were demonstrated in six patients (27%). In these patients with hypoferraemia, oxidative burst was significantly lower than in the patients without hypoferraemia and in the controls. These data suggest that hypoferraemia may be an important predisposing factor in a subgroup of patients with recurrent furunculosis in impairing oxidative killing by neutrophils.     

Volumetric Features for Video Event Detection

Real-world actions occur often in crowded, dynamic environments. This poses a difficult challenge for current approaches to video event detection because it is difficult to segment the actor from the background due to distracting motion from other objects in the scene. We propose a technique for event recognition in crowded videos that reliably identifies actions in the presence of partial occlusion and background clutter. Our approach is based on three key ideas: (1) we efficiently match the volumetric representation of an event against oversegmented spatio-temporal video volumes; (2) we augment our shape-based features using flow; (3) rather than treating an event template as an atomic entity, we separately match by parts (both in space and time), enabling robustness against occlusions and actor variability. Our experiments on human actions, such as picking up a dropped object or waving in a crowd show reliable detection with few false positives.     

Mechanical pressing and semolina preparation from fermented cassava paste during “attiéké” (yucca flour) processing

The production of “attiéké” is typically undertaken in households in Africa, and consequently suffers from inconsistent product quality. To produce “attiéké” having optimal physicochemical and sensory qualities, the effect of compression force on the extent of water removed for a range of fermented paste conditions and paste loadings was investigated using a pneumatic press. Then, the mash was processed into semolina using a granulator. The pressure required to reduce the moisture content to 52% - which, in an earlier study was found to be ideal for semolining, was found to be critically dependent on 10% inoculums, 12 h fermentation and the mass of paste. A relationship was established between the pressure applied and the volume of water expelled. This model provides for optimisation and standardization of the “attiéké” process by controlling the two steps of production in households and industries.     

Autonomous Driving with Concurrent Goals and Multiple Vehicles: Mission Planning and Architecture

We introduce a new distributed planning paradigm, which permits optimal execution and dynamic replanning of complex multi-goal missions. In particular, the approach permits dynamic allocation of goals to vehicles based on the current environment model while maintaining information-optimal route planning for each individual vehicle to individual goals. Complex missions can be specified by using a grammar in which ordering of goals, priorities, and multiple alternatives can be described. We show that the system is able to plan local paths in obstacle fields based on sensor data, to plan and update global paths to goals based on frequent obstacle map updates, and to modify mission execution, e.g., the assignment and ordering of the goals, based on the updated paths to the goals.The multi-vehicle planning system is based on the GRAMMPS planner; the on-board dynamic route planner is based on the D* planner. Experiments were conducted with stereo and high-speed ladar as the to sensors used for obstacle detection. This paper focuses on the multi-vehicle planner and the systems architecture. A companion paper (Brumitt et al., 2001) analyzes experiments with the multi-vehicle system and describes in details the other components of the system.     

Etude electrochimique de la N, N-dimethyl-mesidine en milieu organique. Oxydation electrochimique en presence de phosphonate de diethyle

The electrochimical oxidation of the N, N-dimethylmesidine in acetonitrile (0.1 M LiClO₄) provides a cation radical which fortly deprotonates on a N-methyl. The corresponding neutral radical either dimerises or is oxidized to the iminium cation. The dimer is later on oxidized and gives either trimer and tetramer or the corresponding iminium cation. The iminium cations are characterized by their products of hydrolysis of their adducts with the diethyl phosphonate. The mechanism of formation of characterized products are discussed using electrochemical, chemical yields and the voltamperometric curves evolution.