Neurofuzzy mixture of experts network parallel learning and model construction algorithms

A connection between a fuzzy neural network model with the mixture of experts network (MEN) modelling approach is established. Based on this linkage, two new neuro-fuzzy MEN construction algorithms are proposed to overcome the curse of dimensionality that is inherent in the majority of associative memory networks and/or other rule based systems. The first construction algorithm employs a function selection manager module in an MEN system. The second construction algorithm is based on a new parallel learning algorithm in which each model rule is trained independently, for which the parameter convergence property of the new learning method is established. As with the first approach, an expert selection criterion is utilised in this algorithm. These two construction methods are equivalent in their effectiveness in overcoming the curse of dimensionality by reducing the dimensionality of the regression vector, but the latter has the additional computational advantage of parallel processing. The proposed algorithms are analysed for effectiveness followed by numerical examples to illustrate their efficacy for some difficult data based modelling problems.

Generalized neurofuzzy network modeling algorithms using Bezier-Bernstein polynomial functions and additive decomposition

This paper introduces a new neurofuzzy model construction algorithm for nonlinear dynamic systems based upon basis functions that are Bezier-Bernstein polynomial functions. This paper is generalized in that it copes with n-dimensional inputs by utilising an additive decomposition construction to overcome the curse of dimensionality associated with high n. This new construction algorithm also introduces univariate Bezier-Bernstein polynomial functions for the completeness of the generalized procedure. Like the B-spline expansion based neurofuzzy systems, Bezier-Bernstein polynomial function based neurofuzzy networks hold desirable properties such as nonnegativity of the basis functions, unity of support, and interpretability of basis function as fuzzy membership functions, moreover with the additional advantages of structural parsimony and Delaunay input space partition, essentially overcoming the curse of dimensionality associated with conventional fuzzy and RBF networks. This new modeling network is based on additive decomposition approach together with two separate basis function formation approaches for both univariate and bivariate Bezier-Bernstein polynomial functions used in model construction. The overall network weights are then learnt using conventional least squares methods. Numerical examples are included to demonstrate the effectiveness of this new data based modeling approach.

Parameter estimation based on stacked regression and evolutionary algorithms

A new parameter-estimation algorithm, which minimises the cross-validated prediction error for linear-in-the-parameter models, is proposed, based on stacked regression and an evolutionary algorithm. It is initially shown that cross-validation is very important for prediction in linear-in-the-parameter models using a criterion called the mean dispersion error (MDE). Stacked regression, which can be regarded as a sophisticated type of cross-validation, is then introduced based on an evolutionary algorithm, to produce a new parameter-estimation algorithm, which preserves the parsimony of a concise model structure that is determined using the forward orthogonal least-squares (OLS) algorithm. The PRESS prediction errors are used for cross-validation, and the sunspot and Canadian lynx time series are used to demonstrate the new algorithms.

Autonomous ship collision free trajectory navigation and control algorithms

A new autonomous ship collision free (ASCF) trajectory navigation and control system has been introduced with a new recursive navigation algorithm based on analytic geometry and convex set theory for ship collision free guidance. The underlying assumption is that the geometric information of ship environment is available in the form of a polygon shaped free space, which may be easily generated from a 2D image or plots relating to physical hazards or other constraints such as collision avoidance regulations. The navigation command is given as a heading command sequence based on generating a way point which falls within a small neighborhood of the current position, and the sequence of the way points along the trajectory are guaranteed to lie within a bounded obstacle free region using convex set theory. A neurofuzzy network predictor which in practice uses only observed input/output data generated by on board sensors or external sensors (or a sensor fusion algorithm), based on using rudder deflection angle for the control of ship heading angle, is utilised in the simulation of an ESSO 190000 dwt tanker model to demonstrate the effectiveness of the system.

Prebiotic evaluation of cocoa-derived flavanols in healthy humans by using a randomized, controlled, double-blind, crossover intervention study

BACKGROUND: The absorption of cocoa flavanols in the small intestine is limited, and the majority of the flavanols reach the large intestine where they may be metabolized by resident microbiota. OBJECTIVE: We assessed the prebiotic potential of cocoa flavanols in a randomized, double-blind, crossover, controlled intervention study. DESIGN: Twenty-two healthy human volunteers were randomly assigned to either a high-cocoa flavanol (HCF) group (494 mg cocoa flavanols/d) or a low-cocoa flavanol (LCF) group (23 mg cocoa flavanols/d) for 4 wk. This was followed by a 4-wk washout period before volunteers crossed to the alternant arm. Fecal samples were recovered before and after each intervention, and bacterial numbers were measured by fluorescence in situ hybridization. A number of other biochemical and physiologic markers were measured. RESULTS: Compared with the consumption of the LCF drink, the daily consumption of the HCF drink for 4 wk significantly increased the bifidobacterial (P < 0.01) and lactobacilli (P < 0.001) populations but significantly decreased clostridia counts (P < 0.001). These microbial changes were paralleled by significant reductions in plasma triacylglycerol (P < 0.05) and C-reactive protein (P < 0.05) concentrations. Furthermore, changes in C-reactive protein concentrations were linked to changes in lactobacilli counts (P < 0.05, R(2) = -0.33 for the model). These in vivo changes were closely paralleled by cocoa flavanol-induced bacterial changes in mixed-batch culture experiments. CONCLUSION: This study shows, for the first time to our knowledge, that consumption of cocoa flavanols can significantly affect the growth of select gut microflora in humans, which suggests the potential prebiotic benefits associated with the dietary inclusion of flavanol-rich foods. This trial was registered at clinicaltrials.gov as NCT01091922.

Performance comparison of the optimal and the zero-forcing beamforming algorithms under practical conditions

The optimal and the zero-forcing beamformers are two commonly used algorithms in the subspace-based blind beamforming technology. The optimal beamformer is regarded as the algorithm with the best output SINR. The zero-forcing algorithm emphasizes the co-channel interference cancellation. This paper compares the performance of these two algorithms under some practical conditions: the effect of the finite data length and the existence of the angle estimation error. The investigation reveals that the zero-forcing algorithm can be more robust in the practical environment than the optimal algorithm.

Cholesterol reduction using manufactured foods high in monounsaturated fatty acids: a randomized crossover study

In two separate studies, the cholesterol-lowering efficacy of a diet high in monounsaturated fatty acids (MUFA) was evaluated by means of a randomized crossover trial. In both studies subjects were randomized to receive either a high-MUFA diet or the control diet first, which they followed for a period of 8 weeks; following a washout period of 4–6 weeks they were transferred onto the opposing diet for a further period of 8 weeks. In one study subjects were healthy middle-aged men (n 30), and in the other they were young men (n 23) with a family history of CHD recruited from two centres (Guildford and Dublin). The two studies were conducted over the same time period using identical foods and study designs. Subjects consumed 38% energy as fat, with 18% energy as MUFA and 10% as saturated fatty acids (MUFA diet), or 13% energy as MUFA and 16% as saturated fatty acids (control diet). The polyunsaturated fatty acid content of each diet was 7%. The diets were achieved by providing subjects with manufactured foods such as spreads, ‘ready meals’, biscuits, puddings and breads, which, apart from their fatty acid compositions, were identical for both diets. Subjects were blind to which of the diets they were following on both arms of the study. Weight changes on the diets were less than 1 kg. In the groups combined (n 53) mean total and LDL-cholesterol levels were significantly lower at the end of the MUFA diet than the control diet by 0×29 (SD 0×61) mmol/l (P,0×001) and 0×38 (SD 0×64) mmol/l (P, 0×0001) respectively. In middle-aged men these differences were due to a mean reduction in LDL-cholesterol of ¹11 (SD 12) % on the MUFA diet with no change on the control diet (¹1×1 (SD 10) %). In young men the differences were due to an increase in LDL-cholesterol concentration on the control diet of þ6×2 (SD 13) % and a decrease on the MUFA diet of ¹7×8 (SD 20) %. Differences in the responses of middle-aged and young men to the two diets did not appear to be due to differences in their habitual baseline diets which were generally similar, but appeared to reflect the lower baseline cholesterol concentrations in the younger men. There was a moderately strong and statistically significant inverse correlation between the change in LDLcholesterol concentration on each diet and the baseline fasting LDL-cholesterol concentration (r¹0×49; P,0×0005). In conclusion, diets in which saturated fat is partially replaced by MUFA can achieve significant reductions in total and LDL-cholesterol concentrations, even when total fat and energy intakes are maintained. The dietary approach used to alter fatty acid intakes would be appropriate for achieving reductions in saturated fat intakes in whole populations.

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.

Evaluation of two "integrated" polarimetric Quantitative Precipitation Estimation (QPE) algorithms at C-band

Two so-called “integrated” polarimetric rate estimation techniques, ZPHI (Testud et al., 2000) and ZZDR (Illingworth and Thompson, 2005), are evaluated using 12 episodes of the year 2005 observed by the French C-band operational Trappes radar, located near Paris. The term “integrated” means that the concentration parameter of the drop size distribution is assumed to be constant over some area and the algorithms retrieve it using the polarimetric variables in that area. The evaluation is carried out in ideal conditions (no partial beam blocking, no ground-clutter contamination, no bright band contamination, a posteriori calibration of the radar variables ZH and ZDR) using hourly rain gauges located at distances less than 60 km from the radar. Also included in the comparison, for the sake of benchmarking, is a conventional Z = 282R1.66 estimator, with and without attenuation correction and with and without adjustment by rain gauges as currently done operationally at Météo France. Under those ideal conditions, the two polarimetric algorithms, which rely solely on radar data, appear to perform as well if not better, pending on the measurements conditions (attenuation, rain rates, …), than the conventional algorithms, even when the latter take into account rain gauges through the adjustment scheme. ZZDR with attenuation correction is the best estimator for hourly rain gauge accumulations lower than 5 mm h−1 and ZPHI is the best one above that threshold. A perturbation analysis has been conducted to assess the sensitivity of the various estimators with respect to biases on ZH and ZDR, taking into account the typical accuracy and stability that can be reasonably achieved with modern operational radars these days (1 dB on ZH and 0.2 dB on ZDR). A +1 dB positive bias on ZH (radar too hot) results in a +14% overestimation of the rain rate with the conventional estimator used in this study (Z = 282R^1.66), a -19% underestimation with ZPHI and a +23% overestimation with ZZDR. Additionally, a +0.2 dB positive bias on ZDR results in a typical rain rate under- estimation of 15% by ZZDR.

Randomized controlled trial of full and brief cognitive-behaviour therapy and wait-list for paediatric obsessive-compulsive disorder

Background: Reviews and practice guidelines for paediatric obsessive-compulsive disorder (OCD) recommend cognitive-behaviour therapy (CBT) as the psychological treatment of choice, but note that it has not been sufficiently evaluated for children and adolescents and that more randomized controlled trials are needed. The aim of this trial was to evaluate effectiveness and optimal delivery of CBT, emphasizing cognitive interventions. Methods: A total of 96 children and adolescents with OCD were randomly allocated to the three conditions each of approximately 12 weeks duration: full CBT (average therapist contact: 12 sessions) and brief CBT (average contact: 5 sessions, with use of therapist-guided workbooks), and wait-list/delayed treatment. The primary outcome measure was the child version of the semi-structured interviewer-based Yale-Brown Obsessive Compulsive Scale. Clinical Trial registration: http://www.controlled-trials.com/ISRCTN/; unique identifier: ISRCTN29092580. Results: There was statistically significant symptomatic improvement in both treatment groups compared with the wait-list group, with no significant differences in outcomes between the two treatment groups. Controlled treatment effect sizes in intention-to-treat analyses were 2.2 for full CBT and 1.6 for brief CBT. Improvements were maintained at follow-up an average of 14 weeks later. Conclusions: The findings demonstrate the benefits of CBT emphasizing cognitive interventions for children and adolescents with OCD and suggest that relatively lower therapist intensity delivery with use of therapist-guided workbooks is an efficient mode of delivery.