Reduced bit rate uniform quantisation for SPIHT encoding

Set partitioning in hierarchical trees (SPIHT) is a scalar quantiser for images that have undergone subband decomposition by wavelet transform. Reduced bit rates have been achieved by merging the first and second passes of the already efficient SPIHT algorithm. The modification requires neither entropy encoding nor significant increase to the algorithmic complexity.     

Adaptive packetisation for video streams for bluetooth v.2.0 data rates

Bluetooth v.2.0 interconnects employ multiple data rates and packet types. Proposed is monitoring of the arriving IP packet sizes of an encoded video stream along with the RF background, leading to a scheme with adaptive packetisation and changing data rates over time. Received video quality significantly improves over fixed or semi-adaptive schemes     

Solar photo-Fenton treatment of chip board production waste water

In a joint project the Universidade Federal de Uberlândia and the German Aerospace Center are developing solar water treatment technologies for industrial applications. Wastewater from chip-board production is difficult to detoxify by standard processes. Different advanced oxidation processes using solar light were tested on this effluent. In opposition to TiO₂ treatment, the application of the photo-Fenton process using a compound parabolic collector (CPC) type solar reactor shows excellent results, with a reduction in the COD higher than 70% with the application of about 800 kJ m⁻² of UVA radiation. HPLC analysis shows an efficient degradation of the organic matter present in the effluent (formaldehyde, melamine, urea, wood extractives, lignin and urea/formaldehyde and melamine/formaldehyde resins fragments) prior to their complete disappearance.     

Is Fine‐Grained Simulation Able to Propose New Polyelectrolyte Membranes?

An extensive understanding in the molecular motions that occur in Nafion^® should lead to important development of improved proton exchange membrane for use in fuel cells (PEMFC). As water molecules are added in the system, changes within the Nafion^® chain definitely take place. To visualize such a process, molecular dynamics is especially useful. Can information gained at this level of details be useful to propose new molecules, with ultimately better physical properties, such as higher proton conductivity? For this purpose, we first computed non‐bond parameters stemming from the study of the trifluorosufonic acid. They are inserted in the pcff force field. We then applied the procedure developed in our lab to extract the glass transition temperature of Nafion^® with different water uptakes. The plasticization effect is first confirmed, fostering a molecular analysis. The particular behavior of the sulfur‐sulfur distance is revealed, guiding the design of new monomers.     

Cryogenic temperature plasticity of a bulk amorphous alloy

Unlike crystalline alloys, bulk amorphous alloys exhibit a significantly enhanced plastic strain when tested at cryogenic temperatures. It was observed that both the retarded band propagation and the multiple shear banding are the characteristic features of the shear banding behaviors that are responsible for the enhanced plasticity at cryogenic temperatures. This study explores the retarded band propagation behavior at cryogenic temperatures in terms of the increased viscosity of a material inside a propagating band. The formation of multiple shear bands at cryogenic temperatures is also clarified by evaluating the role played by the cryogenic environment in facilitating the creation of disorder, where local deformation nucleates.     

Excess accident risk among residents of deprived areas

This study examines road risks among residents of deprived neighbourhoods covered by social policy compared with residents of other contiguous neighbourhoods that are socially more privileged. The data used are from accident reports filled in by the police. When these data are brought to the level of the population in the areas studied, the adjusted relative risk for those living in sensitive urban areas compared with those living in other areas is assessed at 1.366 (with a 95% confidence interval from 1.240 to 1.502). Distributions by age and gender are then studied. In the discussion, several hypotheses concerning behaviour, mobility and socio-spatial factors are discussed.     

A Cu-based amorphous alloy with a simultaneous improvement in its glass forming ability and plasticity

An amorphous alloy, Cu₄₃Zr₄₃Al₇Be₇, was synthesized. The alloy showed a large supercooled liquid region (115 °C), a significant glass forming ability (Φ12 mm) and considerable strain to fracture (8–9%), which collectively have not been observed in other Cu-based amorphous alloys. The alloy has a unique microstructure characterized by atomic-scale phase separation, which most likely resulted from the large difference in the mixing enthalpy between the binary pairs. This study discusses a possible mechanism underlying the simultaneous enhancement in the GFA and plasticity by considering the atomic packing state and atomic-scale compositional separation resulting from Al and Be.     

A signaling architecture for wireless ATM access networks

A multiservice wireless Asynchronous Transfer Mode (ATM) access system is considered from a signaling protocol viewpoint. In an attempt to generalize and extend results and experiences obtained from the specification, design, and implementation of fixed ATM‐based access networks, we extend the concept of the broadband V interface (referred to as VB) for application to wireless ATM access networks. The proposed architecture follows the signaling structure of Broadband ISDN (B‐ISDN) User–Network Interface (UNI), thus offering the possibility for integration of the wireless ATM access system into fixed B‐ISDN. It is shown that the use of the proposed access signaling architecture provides cost effective implementations without degrading the agreed Quality of Service (QoS), and simplifies call/connection and handover control. The evaluation of the proposed access signaling protocol structure yields results that fall within acceptable ATM signaling performance measures. A performance comparison of our approach with an alternative access signaling configuration is also carried out to quantify the relative gains. This revised version was published online in August 2006 with corrections to the Cover Date.