Structural features of native cellulose gels and films from their susceptibility to enzymic attack

The reaction of enzymic hydrolysis has been used as a probe to evidence the different structural features of bacterial native cellulose gels and films synthesized from different carbon sources. The gels were found to be more hydrolyzable than were the films, both in terms of reaction extent and of initial reaction rate, by factors increasing with temperature. For instance, a cellulose gel synthesized from glucose showed at 50°C a hydrolysis yield twice as much as that of the corresponding film, thus revealing, in the former case, a higher level of substrate accessibility and enzyme penetrability. It has been suggested that the increase of gel accessibility with temperature can be associated with a corresponding lowering of the amount of structured water close to the polymer chains in the gel. The significant decrease of susceptibility to enzymic attack observed in going from the cellulose film obtained from glucose to that obtained from xylose has been related to the markedly lower value of specific surface area estimated in the latter case. Likely, in the film obtained from xylose, densely packed microfibrils occur that are scarcely accessible to enzyme. In some cases, the reaction progress has been followed by SEM analysis. Microcrystalline cellulose has been also considered for comparison.     

Stoichiometric H2ICEs with water injection

For the most part, gasoline engines operate close to stoichiometry because of the high power density and the easy after treatment through the very well established three-way catalytic converter technology. The lean burn gasoline engine suffers major disadvantages for the after treatment still requiring aggressive research and development to meet future emission standards more than for the lower power density compensated by the better fuel conversion efficiency running lean. Hydrogen engines are usually run ultra-lean to avoid abnormal combustion phenomena and possibly to avoid the emission of nitrogen oxides without the difficult non-stoichiometric after treatment. While the ultra-lean combustion of hydrogen may reduce the formation of NOx within the cylinder but makes the power density very low, the only lean combustion of hydrogen requires after treatment for NOx reduction. The suppression of abnormal combustion in hydrogen engines has been a challenge for the three regimes of abnormal combustion, knock (auto ignition of the end gas region), pre-ignition (uncontrolled ignition induced by a hot spot prior of the spark ignition) and backfire (premature ignition during the intake stroke, which could be seen as an early form of pre-ignition). Direct injection and jet ignition coupled to port water injection are used here to avoid the occurrence of all these abnormal combustion phenomena as well as to control the temperature of gases to turbine in a turbocharged stoichiometric hydrogen engine.     

Identification of fungal contamination and determination of mycotoxigenic molds by micellar electrokinetic capillary chromatography in smoked paprika

The purpose of this work was to analyze the fungal contamination in smoked and unsmoked paprika processed from different cultivars of pepper and to investigate the ability of these and other mycotoxigenic molds to grow and synthesize mycotoxins in smoked paprika. Eighteen mycotoxins were evaluated using micellar electrokinetic capillary chromatography. No relevant differences were found in fungal contamination between smoked and unsmoked paprika. The number of yeasts obtained was low, ranging from 0.4 to 3.29 log CFU g(-1); most of the yeast strains were identified as Cryptococcus spp. followed by Candida spp. All mold counts were <4 log CFU g(-1). Aspergillus, Cladosporium, Penicillium, and Fusarium were the predominant hyphomycete genera. Six mycotoxins were identified in the extracts of several strains isolated from paprika and incubated on malt extract agar. Penicillium expansum followed by Penicillium citrinum and Penicillium raistrickii were the dominant mycotoxigenic fungi isolated. Most of themycotoxin-producing fungi produced detectable amounts of mycotoxins when grown on paprika agar.     

Automatic facial expression recognition in real-time from dynamic sequences of 3D face scans

In this paper, we present a fully-automatic and real-time approach for person-independent recognition of facial expressions from dynamic sequences of 3D face scans. In the proposed solution, first a set of 3D facial landmarks are automatically detected, then the local characteristics of the face in the neighborhoods of the facial landmarks and their mutual distances are used to model the facial deformation. Training two hidden Markov models for each facial expression to be recognized, and combining them to form a multiclass classifier, an average recognition rate of 79.4 % has been obtained for the 3D dynamic sequences showing the six prototypical facial expressions of the Binghamton University 4D Facial Expression database. Comparisons with competitor approaches on the same database show that our solution is able to obtain effective results with the advantage of being capable to process facial sequences in real-time.     

Towards Industrial Application of Intelligent Training Systems

Computer-based training is an area where knowledge-based techniques enable us to achieve new system functionalities which cannot be attained with conventional techniques. Knowledge-based training systems can adapt the course, the lesson and the instructional strategy to the needs and attitude of the individual trainee, so as to obtain a completely individualised instruction. Due to these capabilities they are known as Intelligent Training Systems (ITSs). After their introduction in the mid-eighties with their first successful application in the military sector, ITSs are now mature enough for practical use in civil applications.
This paper presents the experience gained by the authors over the last decade through the realisation of two industrial prototypes in different sectors and the recent development of a full-scale application. Such experience led to a specification methodology and to a development framework which now provide a solid baseline for the industrial application of the ITS technology.     

Variable and constant bitrate in a DVC to H.264/AVC transcoder

Mobile-to-mobile video communications constitute one of the main research areas dealing with the dynamic adaptation of traffic generated by video sources. In a framework where one mobile device sends video information to another, both transmitter and receiver should employ video encoders and decoders with low complexity. In this paper, a Variable/Constant Bitrate DVC to H.264/AVC Transcoder is proposed which takes the advantage of both paradigms in terms of low-complexity algorithms on the end-user device side (DVC encoder and H.264/AVC decoder). The proposed transcoder is based on the hypothesis that common DVC GOPs can be converted to H.264/AVC GOPs without significant rate-distortion and bitrate losses, in a flexible way. An in-depth study of the different frame types available in DVC has been carried out in order to exploit the correlation between them and the most suitable GOP pattern in H.264/AVC. Moreover, a dynamic motion estimation technique is proposed in this paper for optimizing the search area for the motion vectors, with the purpose of being used in combination with the GOP mapping approach. Simulation results show that the proposed approaches reduce the DVC to H.264/AVC transcoder complexity by up to 60% on average, while maintaining the coding efficiency in CBR and VBR scenarios, achieving very high quality results over different types of metrics (both objective and subjective). Finally, we conduct a comparative study with all the most prominent DVC transcoding proposals available in the literature, showing that the proposed transcoder achieves the best results (in terms of PSNR and bitrate).     

Constitutive differences between steely and mealy barley samples associated with endosperm modification

BACKGROUND: Structurally different areas may occur in the endosperm of the barley grain, and they can be visually classified as either mealy or steely. Barleys with a high proportion of grains that are mostly steely often show uneven physical–chemical modification of the endosperm during malting. To study the relationship between steeliness and endosperm modification, two samples of barley cv. Scarlett with contrasting malting quality were analysed. RESULTS: The proportions of steely grains were 77% and 46% in the two samples, which were then defined as steely sample and mealy sample, respectively. The steely sample showed slower modification during malting (in terms of β‐glucan degradation, friability increase, and Calcofluor staining), lower hot water extract (HWE) and acrospire growth, and higher extract viscosity. Endosperm permeation to large molecules (tested with the fluorescein isothiocyanate–dextran conjugate, FITC‐D) closely followed cell wall modification in the steely sample, but this was not so in the mealy sample. CONCLUSIONS: Higher steeliness was associated with higher levels of C hordeins in the grain of barley cv. Scarlett. It is proposed that such hordeins can increase the permeability to large molecules (FITC‐D) but slow modification. Like steeliness and the level of C hordeins, permeability to FITC‐D appears to be more linked to environmental rather than genetic effects. Although a more general association of C hordeins with steeliness of malting barley still has to be ascertained, the negative role of C hordeins in malting quality has been confirmed. Copyright © 2010 Society of Chemical Industry     

Bias Error Analysis of the Generalised Hough Transform

The generalised Hough transform (GHT) extends the Hough transform (HT) to the extraction of arbitrary shapes. In practice, the performance of both techniques differs considerably. The literature suggests that, whilst the HT can provide accurate results with significant levels of noise and occlusion, the performance of the GHT is in fact much more sensitive to noise. In this paper we extend previous error analyses by considering the possible causes of bias errors of the GHT. Our analysis considers both formulation and implementation issues. First, we compare the formulation of the GHT against the general formulation of the standard HT. This shows that, in fact, the GHT definition increases the robustness of the standard HT formulation. Then, in order to explain this paradoxical situation we consider four possible sources of errors that are introduced due to the implementation of the GHT: (i) errors in the computation of gradient direction; (ii) errors due to false evidence attributed to the range of values defined by the point spread function; (iii) errors due to the contribution of false evidence by background points; and (iv) errors due to the non-analytic (i.e., tabular) representation used to store the properties of the model. After considering the effects of each source of error we conclude that: (i) in theory, the GHT is actually more robust than the standard HT; (ii) that clutter and occlusion have a reduced effect in the GHT with respect to the HT; and (iii) that a significant source of error can be due to the use of a non-analytic representation. A non-analytic representation defines a discrete point spread function that is mapped into a discrete accumulator array. The discrete point spread function is scaled and rotated in the gathering process, increasing the amount of inaccurate evidence. Experimental results demonstrate that the analysis of errors is congruent with practical implementation issues. Our results demonstrate that the GHT is more robust than the HT when the non-analytic representation is replaced by an analytic representation and when evidence is gathered using a suitable range of values in gradient direction. As such, we show that errors in the GHT are due to implementation issues and that the technique actually provides a more powerful model-based shape extraction approach than has previously been acknowledged.     

Retrieval of Commercials by Semantic Content: The Semiotic Perspective

Video information processing and retrieval is a key aspect of future multimedia technologies and applications. Commercial videos encode several planes of expression through a rich and dense use of colors, editing effects, viewpoints and rhythms, which are exploited together to attract potential purchasers. Databases of commercials can be accessed in order to analyze how a commercial has been developed, retrieve commercials similar to an example, catalog commercials according to the kind of message conveyed to the user. In this paper, we present a system allowing the retrieval of commercial streams based on their salient semantics. Semantics is regarded from the semiotics perspective: collections of signs and semantic features like colors, editing effects, motion, etc. are used as basic blocks with which the meaning of a commercial is constructed. In our system, it is possible to retrieve commercials according to both the meaning they convey and to their similarity to examples.     

What is this page known for? Computing Web page reputations

The textual content of the Web enriched with the hyperlink structure surrounding it can be a useful source of information for querying and searching. This paper presents a search process where the input is the URL of a page, and the output is a ranked set of topics on which the page has a reputation. For example, if the input is www.gamelan.com, then a possible output is ‘Java'. We propose several algorithmic formulations of the notion of reputation using simple random walk models of Web-browsing behavior. We give preliminary test results on the effectiveness of these algorithms.