Efficient optimal design of uncertain discrete time dynamical systems

In this paper we consider the problem of optimal design of an uncertain discrete time nonlinear dynamical system. The problem is formulated using an a-posterori design criterion, which can account for uncertainties generated by the dynamics of the system itself as well as parametric uncertainties. In general, for most uncertain complex dynamical systems, this type of method is difficult to solve analytically. A numerical scheme is developed for the optimal design that involves two steps. First, in order to obtain a numerical algorithm for the optimal solution, we apply randomized algorithms for average performance synthesis to approximate the optimal solution. Second, using the properties of the Perron–Frobenius operator we develop an efficient computation approach to calculate the stationary distribution for the uncertain dynamical systems and the average performance criteria.     

Productivity of wastewater treatment plants in the Valencia Region of Spain

This study analyses the evolution of productivity over the 2008–2012 period for a homogenous set of 199 wastewater treatment plants that are located in the Valencia Region of Spain and utilize the same treatment technology, using the smoothed bootstrap Malmquist productivity index based on Data Envelopment Analysis (DEA). The results reveal a negative trend in productivity that is mainly the result of resource management rather than an inappropriate level of innovation or use of new technologies. In addition, the effect of exogenous factors on productivity is analysed using the Kruskal-Wallis (KW) test, finding that productivity levels were affected by the quality of the influent water and the size of the plants, but not by the other factors considered.     

An analysis of Malaysia road traffic death distribution by road environment

Various initiatives, strategies and programmes have been taken by the Government of Malaysia to resolve issues pertaining to road traffic deaths. Nevertheless, the implementation of the programmes outlined in Malaysian Road Safety Plan 2006 needs to be enhanced in order to achieve the set targets. In this regard, it is imperative for all parties concerning road safety to determine the factors that significantly contribute to road traffic deaths. According to the Ministry of Works, Malaysia, the blackspot treatment programme (which is centred on the elimination of road hazards by engineering approaches) is successful in reducing the number of injuries due to road traffic accidents up to a certain extent. This study is focussed on analysing road traffic deaths caused by various road environment elements recorded by the police from 2000 to 2011 in order to determine their distribution, proportion and relationship with fatal accidents. The Chi-square test and Marascuilo procedure with 5% level of significance are used in this study. Based on locality, the number of road traffic deaths in rural area (66%) is significantly higher compared with that in urban areas (34%). Based on road category, the number of road traffic deaths is the highest for federal roads, whereas the highest rate of fatalities per kilometre is recorded for expressways. Based on road segment, the number of road traffic deaths is the highest for straight road segments, followed by bends. In addition, the number of road traffic deaths is the highest for Y/T junctions, followed by cross junctions. The lowest number of road traffic deaths is recorded for interchanges and roundabouts. The results show that only 11.25% of the total road traffic deaths are related to road defects. The highest proportion of deaths due to road defects (48.6%) is associated with lack of street lighting provision, whereas road shoulder edge drop-off and potholes contribute 15.4% and 11.2% of road traffic deaths, respectively.     

Fuzzy inference suitability to determine the utilitarian quality of B2C websites

The present paper proposes a new and intuitive model to evaluate the utilitarian e-service quality on textile and fashion B2C websites in Spain. The relevant variables to include into this model have been validated through an in-depth literature review and a reliability study based on an empirical investigation. Among the several methodologies used to develop the model, the paper proves that fuzzy inference systems (FIS) have numerous advantages. The following are particularly relevant: the ease to manage non-linear behaviours and the intuitive way of incorporating knowledge to evaluate B2C websites. This knowledge can stem both: from the expert know-how or from the evaluation of consumer satisfaction on these websites. The knowledge is made explicit through if-then rules which work with linguistic-type concepts −agreed upon by experts, closer to the human reasoning mode. Finally, the usefulness of the proposed model and the defined FIS suitability to evaluate the model are shown.     

GACRM: A dynamic multi-Attribute decision making approach to large-Scale Web service composition

The problem of QoS-aware Web service composition (QWSC), i.e., how to select from a pool of candidate services to construct a composite service with the best overall QoS performance, is an NP-hard problem. To address a large-scale QWSC problem, a novel method is proposed based on information theory, multi-attribute decision making (MADM) and genetic algorithm. To capture complex judgments, the QWSC problem is formulated into a MADM representation which aims to find acceptable solutions assessed by multiple QoS attributes with varying distributions. To solve the MADM problem for QWSC, each QoS attribute is weighted in both a priori, subjective perspective and a posteriori, information-based perspective based on the discriminative capability of QoS attributes for a dynamic pool of candidate services. Furthermore, to solve the large-scale QWSC problem that conventional MADM methods cannot navigate, we develop a GACRM algorithm by integrating genetic algorithm (GA) with Compromise Ratio Method (CRM). Experiments demonstrate that GACRM obtains nearly the same solution ranking by the CRM but scales much better in terms of computation time for large-scale QWSC problems.     

Study the Synthesis,Characterization and Immersion of Dense and Porous Bovine Hydroxyapatite Structures in Hank’s Balanced Salt Solution

The bone-bonding potential of biomaterials is evaluated in vitro through examining the surface apatite formation in Hank’s media to enhance biocompatibility, which is also applicable to facilitate in vivo osseointegration of implantable devices. Hence, bovine hydroxyapatite (BHA) bioceramic structures have been used in various biomedical applications such as orthopedic implants. In this article, the microstructure, in vitro bioactivity, and nanomechanical properties of the synthesized dense and porous BHA are investigated via scanning electron microscopy, x-ray diffraction, energy-dispersive x-ray spectroscopy, Fourier transform infrared spectroscopy, and nanoindentation analysis. From the obtained results, porous BHA mostly possesses adequate requirements for substitution as implants in the human body.     

Nanocomposite Cryogels Based on Poly (Vinyl Alcohol)/Unmodified Na<Superscript>+</Superscript>-Montmorillonite Suitable for Wound Dressing Application: Optimizing Nanoclay Content

A new type of nanocomposite cryogels containing polyvinyl alcohol and 0–10% of hydrophilic natural Na-montmorillonite (Na⁺-MMT), free from any modification, were prepared with a freeze–thaw process. The effects of nanoclay content and the sonication process on the morphology and thermomechanical properties, equilibrium water content (EWC), and the water vapor transmission rate (WVTR) of nanocomposite films were investigated at 37°C, and the amount of optimized nanocaly content was found. The kinetics of water sorption and desorption of the nanocomposites were also studied. The results showed that (Na⁺-MMT) may act as a co-crosslinker and improve the water vapor transmission rate and the swelling characteristics of the nanocomposite cryogels. They also showed the optimized critical concentration of nanoclay in achievement of the required sorption and desorption characteristics as well as WVTR and EWC were within the acceptable range for wound dressing and skin treatment.     

Predicting discharge coefficient of triangular labyrinth weir using Support Vector Regression,Support Vector Regression-firefly,Response Surface Methodology and Principal Component Analysis

Weirs are hydraulic structures which conduct the most powerful flow with large overflow. Discharge flow predication is based on capacity discharge designation by designer. In this paper, the discharge capacity in triangular labyrinth side-weirs is computed by using new techniques with high precision. The four employed techniques for computation of discharge capacity are: Support Vector Regression (SVR), Support Vector Regression–Firefly (SVR- Firefly), Response Surface Methodology (RSM) and Principal Component Analysis (PCA). A comparison between the computed discharge capacity and empirical results is considered in this paper. Determination coefficient (R²), Root Mean Square Error (RMSE), Mean Absolute Percentage Error (MAPE), SI and δ are five statistical indicators which help us to measure the precision of the designed models. The statistical indices indicated that the SVR-Firefly model has the highest ability among the models for simulation, with average MAPE=0.49%, R²=0.991 and RMSE=0.0035. Like the results achieved by the SVR-Firefly, comparatively good results were obtained by both PCA and SVR models. The SVR model suggested the average MAPE value near 1.073 in the training mode under the most unfavorable conditions. The MAPE value equal to 1.23 was also obtained in the test mode. This proves that the value of error rate is tolerable.     

Succinimide-N-sulfonic Acid as a Recyclable Brönsted Acid Catalyst for Synthesis of Pyrano[4,3-b]pyran Derivatives by Using Solar Energy Under Solvent-Free Conditions

Succinimide-N-sulfonic acid as an efficient Brönsted acid catalyzed the synthesis of pyrano[4,3-b]pyrans by using solar energy as a green source of energy under solvent-free conditions. This method has the advantages of high yield, short reaction time, and clean and simple methodology. The catalyst could be recycled without significant loss of activity.     

Natural red pigments from plants and their health benefits: A review

Carotenoids (specifically lycopene), anthocyanins, and betacyanins are natural red pigments found in fruits and vegetables. They possess antioxidant properties beneficial in the prevention of cancer and cardiovascular diseases. Recently, natural colouring agents have attracted increasing attention from the food industry as a substitute to the artificial colouring compounds, which have been discovered to cause negative impact to human’s health upon consumption. There is a growing interest in the natural red pigments in food science, due to their preventive effects on chronic diseases. Stability of the natural pigments should be concerned, as it might affect the saturation of the colour.