Algorithmic and software techniques for embedded vision on programmable processors

In the last few years, programmable architectures centered around high-end DSP processors have emerged as the platform of choice for high-volume embedded vision applications, such as automotive safety and video surveillance. Their programmability inherently addresses the problems presented by the sheer diversity of vision algorithms. This paper provides an overview of high-impact algorithmic and software techniques for embedded vision applications implemented on programmable architectures and discusses several system-level issues. We provide a general discussion and practical examples for the following categories of algorithmic techniques: fast algorithms, reduced dimensionality and mathematical shortcuts. Additionally, we discuss the importance of software techniques such as the use of fixed-point arithmetic, reduced data transfers and cache-friendly programming. In our experience, each of these techniques is a key enabler for real-time embedded vision systems.     

Experimental design for parameter estimation of two time-scale model of photosynthesis and photoinhibition in microalgae

A method for parameter estimation of two time-scale model of photosynthesis and photoinhibition is presented.     

A distributed framework for multi-risk assessment of natural hazards used to model the effects of forest fire on hydrology and sediment yield

Within the European Commission-funded MEDIGRID project, Grid computing technology is used to integrate various natural hazard models and data sets, maintained independently at different centres in Europe, into a single system, accessible to users over the internet. Each centre forms a process (application) or data storage node and has been fitted with the Globus toolkit, which provides the distributed computing environment functionality that is required for the system set up. In addition, several Grid data management components were developed to allow the system to operate on different computing platforms. Access to the data and application management services is enabled through a Grid Portal. A series of portlets enable users to access the system, providing a personalised interface to the Grid. Integration of the individual models required them to be modified as web services, so as to be run remotely over the internet. As the models have different data characteristics, a common data format was adopted for creating harmonised data sets and allowing the exchange of data between the models. As an example, the Fire Spread Engine model is used to derive a map of areas that have been burnt by fire. This forms an input to the SHETRAN hydrology, soil erosion and landslide model, which in turn could provide data for other models such as vegetation regeneration. The use of the system is demonstrated for a site in south-west Spain where a large forest fire occurred on 2 August 2003. The MEDIGRID system marks an advance in the integration of independently constructed models to provide improved hazard assessment technology.     

Moment-method analysis of volume dielectric scatterers. Four independent entire-domain solutions: Is entire-domain philosophy a luxury or necessity in the method of moments?

Four independent methods are presented for entire-domain (large-domain) moment-method analysis of lossy, inhomogeneous dielectric scatterers. They share two basic steps in solving volume integral equations: (1) the approximation of the scatterer geometry by large trilinear hexahedrons; and (2) the approximation of the unknown vector function in the hexahedrons by three-dimensional polynomials. The results are compared among themselves and with those obtained by subdomain (the only existing) methods, demonstrating great superiority of the entire-domain approach in solving three-dimensional scattering and interaction problems. © 1996 John Wiley & Sons, Inc.     

Agmatine Mitigates Inflammation-Related Oxidative Stress in BV-2 Cells by Inducing a Pre-Adaptive Response

Neuroinflammation and microglial activation, common components of most neurodegenerative diseases, can be imitated in vitro by challenging microglia cells with Lps. We here aimed to evaluate the effects of agmatine pretreatment on Lps-induced oxidative stress in a mouse microglial BV-2 cell line. Our findings show that agmatine suppresses nitrosative and oxidative burst in Lps-stimulated microglia by reducing iNOS and XO activity and decreasing O₂⁻ levels, arresting lipid peroxidation, increasing total glutathione content, and preserving GR and CAT activity. In accordance with these results, agmatine suppresses inflammatory NF-kB, and stimulates antioxidant Nrf2 pathway, resulting in decreased TNF, IL-1 beta, and IL-6 release, and reduced iNOS and COX-2 levels. Together with increased ARG1, CD206 and HO-1 levels, our results imply that, in inflammatory conditions, agmatine pushes microglia towards an anti-inflammatory phenotype. Interestingly, we also discovered that agmatine alone increases lipid peroxidation end product levels, induces Nrf2 activation, increases total glutathione content, and GPx activity. Thus, we hypothesize that some of the effects of agmatine, observed in activated microglia, may be mediated by induced oxidative stress and adaptive response, prior to Lps stimulation.     

Properties of copper matrix reinforced with various size and amount of Al2O3 particles

Copper matrix was reinforced with Al₂O₃ particles of different size and amount by internal oxidation and mechanical alloying accomplished using high-energy ball milling in air. The inert gas-atomised prealloyed copper powder containing 1 wt.% Al as well as a mixture of electrolytic copper powder and 3 wt.% commercial Al₂O₃ powder served as starting materials. Milling of Cu-1 wt.% Al prealloyed powder promoted formation of fine dispersed particles (1.9 wt.% Al₂O₃, approximately 100 nm in size) by internal oxidation. During milling of Cu-3 wt.% Al₂O₃ powder mixture the uniform distribution of commercial Al₂O₃ particles has been obtained. Following milling, powders were treated in hydrogen at 400 °C for 1 h in order to eliminate copper oxides formed at the surface during milling. Compaction was executed by hot-pressing. Compacts processed from 5 to 20 h-milled powders were additionally subjected to high-temperature exposure at 800 °C in order to examine their thermal stability and electrical conductivity. Compacts of Cu-1 wt.% Al prealloyed powders with finer Al₂O₃ particles and smaller grain size exhibited higher microhardness than compacts of Cu-3 wt.% Al₂O₃ powder mixture. This indicates that nano-sized Al₂O₃ particles act as a stronger reinforcing parameter of the copper matrix than micro-sized commercial Al₂O₃ particles. Improved thermal stability of Cu-1 wt.% Al compacts compared to Cu-3 wt.% Al₂O₃ compacts implies that nano-sized Al₂O₃ particles act more efficiently as barriers obstructing grain growth than micro-sized particles. Contrary, the lower electrical conductivity of Cu-1 wt.% Al compacts is the result of higher electron scatter caused by nano-sized Al₂O₃ particles.     

Ultrasound effect on structure and properties of Cu–0.5Cr under upsetting

ABSTRACT

We studied the effect of the regimes of ultrasonic action on the structural transformation during free upsetting with 50% reduction of the copper alloy Cu–0.5Cr. In the process of deformation, the samples were subjected to intermittent and continuous ultrasonic actions. It can be noted that the application of ultrasonic vibrations in the process of deformation leads in both cases to a reduction in yield strength. Under a continuous ultrasonic action with a power of 640?W, the most developed structure is formed, with a fraction of high-angle boundaries equal to 32.4%, with the lowest values of coherent scattering regions, density of dislocations and microdistortions, while the decline in yield strength of the material under deformation is 40?MPa.

This paper is part of a Thematic Issue on Copper and its Alloys.     

Treatment of Chlorophenols by UV-Based Processes: Correlation of Oxidation By-Products, Wastewater Parameters, and Toxicity

The aim of the study was to evaluate the toxicity and biodegradability of para-chlorophenol (p-CP) model wastewater when treated by UV and UV/H2O2 processes. We investigated the correlations between the toxicity and the concentration of p-CP and its oxidation by-products, as well as other parameters—summarizing characteristics which potentially indicate hazardous water components, e.g., AOX (adsorbable organic halides), TOC (total organic carbon), and COD and BOD5 (chemical and biochemical oxygen demand). Biodegradability is estimated by the BOD5/COD ratio. The toxic effects were investigated on luminescent bacteria Vibrio fischeri, determining the EC50 value. The correlation between each data pair was estimated using a statistical approach calculating the Spearman rank coefficients. The biodegradability of the p-CP model wastewater was improved by the UV/H2O2 process; the BOD5/COD ratio increased from 0.37 to 0.73 after a 1-h treatment (F = 1243??mJ?cm-2). According to the calculated Spearman rank coefficient, the highest correlation with toxicity data among all monitored parameters was obtained for hydroquinone and benzoquinone, as by-products of p-CP degradation, as well as for the BOD5/COD ratio.