Response level crossing rate of a linear system excited by a partially specified Gaussian load process

The problem of determining the maximum mean response level crossing rate of a linear system driven by a partially specified Gaussian load process has been considered. The partial specification of the load is given only in terms of its total average energy. The critical input power spectral (PSD) function, which maximizes the mean response level crossing rate, is obtained. The critical input PSD turns out to be highly narrow-banded which fails to capture the erratic nature of the excitation. Consequently, the trade-off curve between the maximum mean response level crossing rate and the maximum disorder in the input process, quantified in terms of its entropy rate, has been generated. The method of Pareto optimization is used to tackle the conflicting objectives of the simultaneous maximization of the mean response level crossing rate and the input entropy rate. The non-linear multi-objective optimization has been carried out using a recently developed multi-criteria genetic algorithm scheme. Illustrative example of determining the critical input of an axially vibrating rod, excited by a partially specified stationary Gaussian load process, has been considered.     

Complexity and design of QoS routing algorithms in wireless mesh networks

Quality of service (QoS) provisioning in wireless mesh networks (WMNs) is an open issue to support emerging multimedia services. In this paper, we study the problem of QoS provisioning in terms of end-to-end bandwidth allocation in WMNs. It is challenging due to interferences in the networks. We consider widely used interference models and show that except a few special cases, the problem of finding a feasible path is NP-complete under the models. We propose a k-shortest path based algorithmic framework to solve this problem. We also consider the problem of optimizing network performance by on-line dynamic routing, and adapt commonly used conventional QoS routing metrics to be used in WMNs. We find the optimal solutions for these problems through formulating them as optimization models. A model is developed to check the existence of a feasible path and another to find the optimal path for a demand; moreover, an on-line optimal QoS routing algorithm is developed. Comparing the algorithms implemented by the proposed framework with the optimization models shows that our solution can find existing feasible paths with high probability, efficiently optimizes path lengths, and has a comparable performance to the optimal QoS routing algorithm. Furthermore, our results show that contrary to wireline networks, minimizing resource consumption should be preferred over load distribution even in lightly loaded WMNs.     

Image registration using log-polar mappings for recovery of large-scale similarity and projective transformations.

This paper describes a novel technique to recover large similarity transformations (rotation/scale/translation) and moderate perspective deformations among image pairs. We introduce a hybrid algorithm that features log-polar mappings and nonlinear least squares optimization. The use of log-polar techniques in the spatial domain is introduced as a preprocessing module to recover large scale changes (e.g., at least four-fold) and arbitrary rotations. Although log-polar techniques are used in the Fourier-Mellin transform to accommodate rotation and scale in the frequency domain, its use in registering images subjected to very large scale changes has not yet been exploited in the spatial domain. In this paper, we demonstrate the superior performance of the log-polar transform in featureless image registration in the spatial domain. We achieve subpixel accuracy through the use of nonlinear least squares optimization. The registration process yields the eight parameters of the perspective transformation that best aligns the two input images. Extensive testing was performed on uncalibrated real images and an array of 10,000 image pairs with known transformations derived from the Corel Stock Photo Library of royalty-free photographic images.     

Gastroprotective effects of herbal medicines (roots)

Herbal medicines are now commonly used all over the world and this has increased global demand. Quality, safety, and efficacy of these drugs have become a serious concern. This review presents the medicinal plants cited in folklore that are used to treat gastrointestinal ulcers. Electronic databases, that is, Web of Science, PubMed, Scopus, and Google Scholar were searched to identify the gastroprotective effects of each plant. Ethnopharmacological studies have reported various botanical products with antiulcer activities, but there has been limited scientific research, presenting clinical data to validate the efficacy and safety of medicinal herbs as gastroprotective agents. Most studies centered on pharmacological properties of medicinal herbs as used animals models. This information has prompted us to compile a list of the medicinal herbs cited in folklore with gastroprotective activity.     

A multi-criteria context-sensitive approach for social image collection summarization

Recent increase in the number of digital photos in the content sharing and social networking websites has created an endless demand for techniques to analyze, navigate, and summarize these images. In this paper, we focus on image collection summarization. Earlier methods in image collection summarization consider representativeness and diversity criteria while recent ones also consider other criteria such as image quality, aesthetic or appeal. In this paper, we propose a multi-criteria context-sensitive approach for social image collection summarization. In the proposed method, two different sets of features are combined while each one looks at different criteria for image collection summarization: social attractiveness features and semantic features. The first feature set considers different aspects that make an image appealing such as image quality, aesthetic, and emotion to create attractiveness score for input images while the second one covers semantic content of images and assigns semantic score to them. We use social network infrastructure to identify attractiveness features and domain ontology for extracting ontology features. The final summarization is provided by integrating the attractiveness and semantic features of input images. The experimental results on a collection of human generated summaries on a set of Flickr images demonstrate the effectiveness of the proposed image collection summarization approach.     

Removal of Cadmium from Aqueous Solution by Nano Composites of Bentonite /TiO2 and Bentonite/ZnO Using Photocatalysis Adsorption Process

Silicon - In this study, bentonite/TiO2 and bentonite/ZnO nanoparticles were used for studying the cadmium removal from the aqueous solution. The experiments were done in a batch condition under...     

Dynamic optimization of spur gears

This paper presents a global optimization method focused on gear vibration reduction by means of profile modifications. A nonlinear dynamic model is used to study the vibration behavior; such model is validated using data available in literature. The optimization method considers different regimes and torque levels; the objective function can be the static transmission error or the maximum amplitude of the gear vibration in terms of dynamic transmission error. The procedure finds the optimal profile modification that reduces the vibrations over a wide range of operating conditions. In order to reduce the computational cost, a Random-Simplex optimization algorithm is developed; the optimum reliability is estimated using a Monte Carlo simulation. The approach shows good performances for the computational efficiency as well as the reliability of results. Finally, an application to High Contact Ratio (HCR) gears is presented and an extremely good performance is obtained by combining optimization procedures and HCR properties.     

Fabrication and modification of polyvinylchloride based heterogeneous cation exchange membranes by simultaneously using Fe-Ni oxide nanoparticles and Ag nanolayer: Physico-chemical and antibacterial characteristics

Polyvinylchloride-blend-styrene butadiene rubber based nanocomposite cation exchange membranes were prepared by solution casting technique. Iron-oxide nanoparticles and Ag-nanolayer were simultaneously utilized as filler and surface modifier in membrane fabrication. The effects of Ag-nanolayer film thickness on membrane physicochemical and antibacterial characteristics of nanocomposite PVC-blend-SBR/Iron-oxide nanoparticles were studied. SEM images showed membrane roughness decreasing by Ag nanolayer thickness increasing. Membrane charge density and selectivity declined by Ag nanolayer coating up to 5 nm in membranes and then showed increasing trend by more nanolayer thickness. Ionic flux also showed increasing trend. Membranes showed good ability in E-Coli removal. 20 nm Ag-nanolayer coated membrane showed better performance compared to others.