A specific pole placement technique to minimise hardware requirements within a real time terrestrial and cable video echo canceller

The real time hardware architecture of a deterministic video echo canceller (deghoster) system is presented. The deghoster is capable of calculating all the multipath channel distortion characteristics from terrestrial and cable television in one single pass while performing real time video in-line ghost cancellation. The results from the actual system are also presented in this paper.

Genetic algorithms for optimal control of beer fermentation

This paper uses genetic algorithms to optimise the mathematical model of a beer fermentation process that operates in batch mode. The optimisation is based in adjusting the temperature profile of the mixture during a fixed period of time in order to reach the required ethanol levels but considering certain operational and quality restrictions.

Konjac glucomannan hydrolysate beneficially modulates bacterial composition and activity within the faecal microbiota

The prebiotic potential of a konjac glucomannan hydrolysate (GMH) was investigated in vitro using batch cultures inoculated with human faeces. Bacterial enumeration was carried out using the culture independent technique, fluorescent in situ hybridisation (FISH), and short chain fatty acid (SCFA) production was monitored by gas chromatography. The populations of Bifidobacterium genus, Lactobacillus–Enterococcus group and the Atopobium group all significantly increased after GMH and inulin fermentation. The Bacteroides–Prevotella group had a lower end population after GMH fermentation while inulin gave an increase, although these differences were not significant. No significant differences in SCFA concentrations were observed between inulin and GMH. As with inulin, GMH produced selective stimulation of beneficial gut microbiota and a favourable SCFA profile. In order to confirm a beneficial effect of GMH further in vivo studies involving healthy human volunteers should be considered.

Dynamic Niche Clustering: a fuzzy variable radius niching technique for multimodal optimisation in GAs

This paper describes the recent developments and improvements made to the variable radius niching technique called Dynamic Niche Clustering (DNC). DNC is fitness sharing based technique that employs a separate population of overlapping fuzzy niches with independent radii which operate in the decoded parameter space, and are maintained alongside the normal GA population. We describe a speedup process that can be applied to the initial generation which greatly reduces the complexity of the initial stages. A split operator is also introduced that is designed to counteract the excessive growth of niches, and it is shown that this improves the overall robustness of the technique. Finally, the effect of local elitism is documented and compared to the performance of the basic DNC technique on a selection of 2D test functions. The paper is concluded with a view to future work to be undertaken on the technique.

A variable radius niching technique for speciation in genetic algorithms

In this paper, a continuation of a variable radius niche technique called Dynamic Niche Clustering developed by (Gan & Warwick, 1999) is presented. The technique employs a separate dynamic population of overlapping niches that coexists alongside the normal population. An empirical analysis of the updated methodology on a large group of standard optimisation test-bed functions is also given. The technique is shown to perform almost as well as standard fitness sharing with regards to stability and the accuracy of peak identification, but it outperforms standard fitness sharing with regards to time complexity. It is also shown that the technique is capable of forming niches of varying size depending on the characteristics of the underlying peak that the niche is populating.

In vitro gas production and nitrogen degradability of tannin-containing tree fruits in response to incremental levels of polyethylene glycol

This study was designed to determine the response of in vitro fermentation parameters to incremental levels of polyethylene glycol (PEG) when tanniniferous tree fruits (Dichrostachys cinerea, Acacia erioloba, A. erubiscens, A. nilotica and Piliostigma thonningii) were fermented using the Reading Pressure Technique. The trivalent ytterbium precipitable phenolics content of fruit substrates ranged from 175 g/kg DM in A. erubiscens to 607 g/kg DM in A. nilotica, while the soluble condensed tannin content ranged from 0.09 AU550nm/40mg in A. erioloba to 0.52 AU550nm/40 mg in D. cinerea. The ADF was highest in P. thonningii fruits (402 g/kg DM) and lowest in A. nilotica fruits (165 g/kg DM). Increasing the level of PEG caused an exponential rise to a maximum (asymptotic) for cumulative gas production, rate of gas production and nitrogen degradability in all substrates except P. thonningii fruits. Dry matter degradability for fruits containing higher levels of soluble condensed tannins (D. cinerea and P. thonningii), showed little response to incremental levels of PEG after incubation for 24 h. The minimum levels of PEG required to maximize in vitro fermentation of tree fruits was found to be 200 mg PEG/g DM of sample for all tree species except A. erubiscens fruits, which required 100 mg PEG/g DM sample. The study provides evidence that PEG levels lower than 1 g/g DM sample can be used for in vitro tannin bioassays to reduce the cost of evaluating non-conventional tanniniferous feedstuffs used in developing countries in the tropics and subtopics. The use of in vitro nitrogen degradability in place of the favoured dry matter degradability improved the accuracy of PEG as a diagnostic tool for tannins in in vitro fermentation systems.

In vitro fermentation characteristics of whole grain wheat flakes and the effect of toasting on prebiotic potential

Population studies have shown a positive correlation between diets rich in whole grains and a reduced risk of developing metabolic diseases, like diabetes, cardiovascular disease, and certain cancers. However, little is known about the mechanisms of action, particularly the impact different fermentable components of whole grains have on the human intestinal microbiota. The modulation of microbial populations by whole grain wheat flakes and the effects of toasting on digestion and subsequent fermentation profile were evaluated. Raw, partially toasted, and toasted wheat flakes were digested using simulated gastric and small intestinal conditions and then fermented using 24-hour, pH-controlled, anaerobic batch cultures inoculated with human feces. Major bacterial groups and production of short-chain fatty acids were compared with those for the prebiotic oligofructose and weakly fermented cellulose. Within treatments, a significant increase (P<.05) in bifidobacteria numbers was observed upon fermentation of all test carbohydrates, with the exception of cellulose. Toasting appeared to have an effect on growth of lactobacilli as only fermentation of raw wheat flakes resulted in a significant increase in levels of this group.

Evaluating mid-infrared spectroscopy as a new technique for predicting sensory texture attributes of processed cheese

The objective of this study was to investigate the potential application of mid-infrared spectroscopy for determination of selected sensory attributes in a range of experimentally manufactured processed cheese samples. This study also evaluates mid-infrared spectroscopy against other recently proposed techniques for predicting sensory texture attributes. Processed cheeses (n = 32) of varying compositions were manufactured on a pilot scale. After 2 and 4 wk of storage at 4 degrees C, mid-infrared spectra ( 640 to 4,000 cm(-1)) were recorded and samples were scored on a scale of 0 to 100 for 9 attributes using descriptive sensory analysis. Models were developed by partial least squares regression using raw and pretreated spectra. The mouth-coating and mass-forming models were improved by using a reduced spectral range ( 930 to 1,767 cm(-1)). The remaining attributes were most successfully modeled using a combined range ( 930 to 1,767 cm(-1) and 2,839 to 4,000 cm(-1)). The root mean square errors of cross-validation for the models were 7.4(firmness; range 65.3), 4.6 ( rubbery; range 41.7), 7.1 ( creamy; range 60.9), 5.1(chewy; range 43.3), 5.2(mouth-coating; range 37.4), 5.3 (fragmentable; range 51.0), 7.4 ( melting; range 69.3), and 3.1 (mass-forming; range 23.6). These models had a good practical utility. Model accuracy ranged from approximate quantitative predictions to excellent predictions ( range error ratio = 9.6). In general, the models compared favorably with previously reported instrumental texture models and near-infrared models, although the creamy, chewy, and melting models were slightly weaker than the previously reported near-infrared models. We concluded that mid-infrared spectroscopy could be successfully used for the nondestructive and objective assessment of processed cheese sensory quality..

Surface activity of surfactin recovered and purified from fermentation broth using a two-step ultrafiltration (UF) process

B. subtilis under certain types of media and fermentation conditions can produce surfactin, a biosurfactant which belongs to the lipopeptide class. Surfactin has exceptional surfactant activity, and exhibits some interesting biological characteristics such as antibacterial activity, antitumoral activity against ascites carcinoma cells, and a hypocholesterolemic activity that inhibits cAMP phosphodiesterase, as well as having anti-HIV properties. A cost effective recovery and purification of surfactin from fermentation broth using a two-step ultrafiltration (UF) process has been developed in order to reduce the cost of surfactin production. In this study, competitive adsorption of surfactin and proteins at the air-water interface was studied using surface pressure measurements. Small volumes of bovine serum albumin (BSA) and β-casein solutions were added to the air-water interface on a Langmuir trough and allowed to stabilise before the addition of surfactin to the subphase. Contrasting interfacial behaviour of proteins was observed with β-casein showing faster initial adsorption compared to BSA. On introduction of surfactin both proteins were displaced but a longer time were taken to displace β-casein. Overall the results showed surfactin were highly surface-active by forming a β-sheet structure at the air-water interface after reaching its critical micelle concentration (CMC) and were effective in removing both protein films, which can be explained following the orogenic mechanism. Results showed that the two-step UF process was effective to achieve high purity and fully functional surfactin.

In vitro fermentation and prebiotic potential of novel low molecular weight polysaccharides derived from agar and alginate seaweeds

Fermentation properties and prebiotic potential of novel low molecular weight polysaccharides (LMWPs) derived from agar and alginate bearing seaweeds was investigated. Ten LMWPs were supplemented to pH, temperature controlled anaerobic batch cultures inoculated with human feces from three donors, in triplicate. Microbiota changes were monitored using Fluorescent in-situ hybridization and short chain fatty acids, the fermentation end products were analysed using gas chromatography. Of the ten LMWPs tested, Gelidium seaweed CC2253 of molecular weight 64.64 KDa showed a significant increase in bifidobacterial populations from log(10) 8.06 at 0 h to log(10) 8.55 at 24 h (p = 0.018). For total bacterial populations, alginate powder CC2238 produced a significant increase from log(10) 9.01 at 0 h to log(10) 9.58 at 24 h (p = 0.032). No changes were observed in the other bacterial groups tested viz. Bacteroides, Lactobacilli/Enterococci, Eubacterium rectale/Clostridium coccoides and Clostridium histolyticum. The polysaccharides also showed significant increases in total SCFA production, particularly acetic and propionic acids, indicating that they were readily fermented. In conclusion, some LMWPs derived from agar and alginate bearing seaweeds were fermented by gut bacteria and exhibited potential to be used a novel source of prebiotics.