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Nemati S.,Islamic Azad University at Arsanjan | Basiri M.E.,University of Isfahan
Expert Systems with Applications | Year: 2011

With the growing trend toward remote security verification procedures for telephone banking, biometric security measures and similar applications, automatic speaker verification (ASV) has received a lot of attention in recent years. The complexity of ASV system and its verification time depends on the number of feature vectors, their dimensionality, the complexity of the speaker models and the number of speakers. In this paper, we concentrate on optimizing dimensionality of feature space by selecting relevant features. At present there are several methods for feature selection in ASV systems. To improve performance of ASV system we present another method that is based on ant colony optimization (ACO) algorithm. After feature reduction phase, feature vectors are applied to a Gaussian mixture model universal background model (GMM-UBM) which is a text-independent speaker verification model. The performance of proposed algorithm is compared to the performance of genetic algorithm on the task of feature selection in TIMIT corpora. The results of experiments indicate that with the optimized feature set, the performance of the ASV system is improved. Moreover, the speed of verification is significantly increased since by use of ACO, number of features is reduced over 80% which consequently decrease the complexity of our ASV system. © 2010 Elsevier Ltd. All rights reserved. Source


Zare A.,Islamic Azad University at Arsanjan | Ghasemi M.,Moshiran consulting company
International Review on Modelling and Simulations | Year: 2010

Loads, generators, and power system's structures are effective factors that significantly affect the voltage stability. The selection of a sufficient model for loads has a significant effect on the accuracy of voltage stability analysis. The constant power load model is commonly used in voltage stability studies and specially in examining the effects of FACTS devices. However, the actual loads in power systems are not constant power. This paper focuses on the hidden effects of the interaction between loads and STATCOM on the voltage stability. Simulations results revealed the salient effect of loads on the STATCOM performance. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved. Source


Zarei M.,Hormozgan University | Mohamadzadeh M.,Islamic Azad University at Arsanjan
Tetrahedron | Year: 2011

A series of 3-thiolated β-lactams were synthesized by [2+2] ketene-imine cycloaddition reaction from S-substituted mercaptoacetic acids and Schiff bases. Then, some of the 3-methylthio β-lactams were converted to 3-(methylsulfinyl) β-lactams and 3-(methylsulfonyl) β-lactams using m-CPBA under different reaction conditions. All the compounds were characterized by spectral data and elemental analyses and were evaluated for their in vitro antibacterial and antifungal activities against pathogenic strains including Staphylococcus aureus (Methicillin resistant strain). The preliminary screening results indicated that some of these compounds demonstrated moderate to very good antibacterial and antifungal activities. © 2011 Elsevier Ltd. All rights reserved. Source


Moayedi H.,University Putra Malaysia | Asadi A.,Islamic Azad University | Moayedi F.,Islamic Azad University at Arsanjan | Huat B.B.K.,University Putra Malaysia
International Journal of Electrochemical Science | Year: 2011

The focus of this research is to study the influence of polyvinyl alcohol (PVA) adsorption on the zeta potential properties of two tropical soil namely peat, and kaolinite. Two different PVA species were used, partially hydrolyzed (PVA-T) as well as fully hydrolyzed (PVA-F). As results, adding the PVA species into the suspended colloids led to an increase of zeta potential in their surfaces, contrary to measuring done in water. The zeta potential of the Peat soil varied from 25.26 to -95.1 mV, according to the PVA type and concentration. Kaolinite, however, showed zeta potential varied from +32.4 to -161.78. Negative charge in both peat and kaolinite soils were highly pH dependent and their surface charge dropped to zero at pH 3.1 to 3.4. Using PVA cause a significant reduction in isoelectric point (IEP) of soil samples to about 1.9 for peat and 2.1 for kaolinite. PVA-F enhanced the negative zeta potential than PVA-T. However, increasing of zeta potential in negative sign with increasing degree of polymerization can be observed in both PVA-T and PVA-F samples. © 2011 by ESG. Source


Miri H.R.,Islamic Azad University at Arsanjan
Advances in Environmental Biology | Year: 2011

Allelopathy, the ability of plants to inhibit growth of other plants, is a potential source for weed control in crops that can use in sustainable crop production. In order to evaluate allelopathic potential of some important crop species on wild barley (Hordeum spontaneum L.), a major weed of wheat (Triticum aestivum L.) in Iran, an experiment was conducted using seedling extract of 20 crop species. Plants were grown to flowering stage in a greenhouse, separated into leaf, stem and roots, dried and ground, for preparing water extract. Plant extract were tested on germination and root growth of wild barley and wheat. Results showed that most crop species reduced wild barley germination and root growth. Species like sugar beet, safflower, sorghum and most legume species showed the highest inhibitory effect. Sunflower, chick pea and chickling pea reduced wild barley growth more than wheat, which showed that there is a potential for weed control in wheat using these species. There is also a cosiderble differences in inhibitory effects of different plant parts. For example in cereal the highest inhibitory related to stem extract while, in pulses all plant parts showed high inhibitory against wild barley. Plants evaluated in this study have the potential to be used for biologically based weed control methods in organic cropping systems. Source

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