A comparative study of nature inspired optimization algorithms on multilevel thresholding image segmentation

In this paper, five successful nature inspired algorithms; the artificial tree algorithm (AT), the particle swarm optimization (PSO), the genetic algorithm (GA), the cultural algorithm (CA), and the cuckoo search algorithm (CS) have been compared on multilevel image thresholding. The segmentation process is based on the Levine and Nazif intra class uniformity criterion which is seen as an optimization problem. The comparison performances are in terms of the value of the objectif function, the peak signal to noise ratio (PSNR) and the computation time. Empirical results over different benchmark images for different threshold numbers reveal the robustness, the reliability and the rapidity of the cultural algorithm (CA).

     

Large Eddy simulation for lean premixed combustion

In comparison to previous numerical studies interested in the ORACLES benchmark (One Rig for Accurate Comparisons with Large Eddy Simulations), the present study demonstrates the advantages of LES‐WALE model in both inert and reacting flows using the Fluent‐CFD. So, the confirmation is based on the experimental research effort that was involved in the European Union‐funded research program MOLECULES (Modelling of Low Emissions Combustors Using Large Eddy Simulations), for three parameters: longitudinal velocity, longitudinal velocity fluctuation, and length of recirculation zone. In line with what was observed by the experimental reference study, the dynamic model (LES‐WALE) predicts, respectively, as well as the asymmetry and the symmetry, for both inert and reacting flows. In addition, the simulation succeeds to predict the zones of recirculation and shows the differences between the two cases, inert and reacting flows. Moreover, results have been compared with those of the k–ε model performed by Kurenkov and Obserlack [Kurenkov and Obserlack, Flow Turbulence Combustion 74, 387–407 (2005)] study. © 2012 Canadian Society for Chemical Engineering     

Sinus node dysfunction after complete correction of tetralogy of Fallot. Report of a case

Atrioventricular conduction defects after complete correction of tetralogy of Fallot are well known and their prevalence is decreasing with improved operative techniques. On the other hand, sinus node dysfunction has not been described after this type of surgery. The authors report the case of a 24 year old patient operated at the age of 2 for a favourable form of tetralogy of Fallot. In the long-term, this patient had a minimal anatomical sequel (mild pulmonary insufficiency) and first degree AVB with complete right bundle branch block with sinus bradycardia on the surface ECG. A recent aggravation of the patient's functional status led to rhythmological investigation which showed chronotropic atrial incompetence with nodal atrioventricular delay. The patient was implanted with a permanent DDD cardiac pacemaker programmed in the DDDR mode with a good outcome. Atrial chronotropic incompetence is one of the modes of expression of sinus node dysfunction. This has not been previously described in this context. This form of sinus node dysfunction should be systematically excluded after surgical cure of tetralogy of Fallot by exercise stress testing and 24 hour Holter ECG. Symptomatic patients are greatly improved by permanent cardiac pacing with hysteresis.     

The fate of furfurals and other volatile markers during the baking process of a model cookie

This work investigates the generation and the evolution of some neoformed compounds formed during the baking of a model biscuit. Thank to their physicochemical properties of volatility and hydrophobicity, furfurylic compounds were followed by a double approach: the analysis of the volatile fraction extracted from food matrix and from the vapours released during the thermal process. 5-Hydroxymethylfurfural (HMF) was the main furfurylic compound formed, it followed an exponential kinetic in both the matrix and the vapours of baking biscuits. However, at the very final stage of baking a drop in HMF was observed in the cookie matrix whereas increasing amounts of HMF were still found in the vapours of baking. Moreover, some degradation products of HMF such as furaldehyde (F) and 2-methylfurfural (MF) were also detected. These observations support the hypothesis of a concomitant volatilization and degradation of HMF during the baking of the model cookie, under our experimental conditions.     

Synthesis of controllers for symmetric systems

This article deals with supervisory control problem for coloured Petri (CP) nets. Considering a CP-net, we build a condensed version of the ordinary state-space, namely the symbolic reachability graph (SRG). This latter graph allows to cope with state-space explosion problem for symmetric systems. The control specification can be expressed in terms of either forbidden states or forbidden sequences of transitions. According to these specifications, we derive the controller by applying the theory of regions on the basis of the SRG. Thanks to expressiveness power of CP-nets, the obtained controller to be connected to the plant model is reduced to one single place.     

Impacts of natural antioxidants on the fatty acid profiles of vacuum-packaged tuna-like muscles

The impacts of natural preservatives such as olive leaf (Olea europaea L.) and sweet marjoram (Origanum majorana L.) extracts (OLE and SME) and cold storage on the fatty acid profiles of vacuum-packaged tuna-like muscles were evaluated. At the end of the storage time, the lowest content of the total saturated fatty acids (SFA) was observed in both ordinary and dark muscles of the treated samples (OLE and SME) whereas the highest content was found in their counterparts from the untreated samples (control). The total polyunsaturated fatty acid (PUFA) and total monounsaturated fatty acid (MUFA) contents decreased markedly in both ordinary and dark muscles of the control samples. In contrast, treated samples remained relatively stable throughout the storage time since the employment of plant extracts had protective effects against lipid oxidation and help maintain MUFA and PUFA levels in frigate tuna muscles. In addition, the PUFA/SFA ratio and polyene index which are considered important dietetic parameters showed that the used plant extracts (OLE and SME) did not result in a reduction in the PUFA/SFA ratio and prevented PUFA damage in both frigate tuna muscles during storage. Thus, the use of plant extracts such as OLE and SME can be recommended as natural preservatives for the fish processing industry.