排序方式： 共有82条查询结果，搜索用时 15 毫秒
51.
Tayefeh Mahmoudi Maryam Taghiyareh Fattaneh Forouzideh Nafiseh Lucas Caro 《Neural computing & applications》2012,21(1):1-8
Generalization performance of support vector machines (SVM) with Gaussian kernel is influenced by its model parameters, both the error penalty parameter and the Gaussian kernel parameter. After researching the characteristics and properties of the parameter simultaneous variation of support vector machines with Gaussian kernel by the parameter analysis table, a new area distribution model is proposed, which consists of optimal straight line, reference point of area boundary, optimal area, transition area, underfitting area, and overfitting area. In order to improve classification performance of support vector machines, a genetic algorithm based on change area search is proposed. Comparison experiments show that the test accuracy of the genetic algorithm based on change area search is better than that of the two-linear search method. 相似文献
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Today, large amounts of data are generated in various applications such as smart cities and social networks, and their processing requires a lot of time. One of the methods of processing data types and reducing computational time on data is the use of dimension reduction methods. Reducing dimensions is a problem with the optimization approach and meta-heuristic methods can be used to solve it. Namib beetles are an example of intelligent insects and creatures in nature that use an interesting strategy to survive and collect water in the desert. In this article, the behavior of Namib beetles has been used to collect water in the desert to model the Namib beetle optimization (NBO) algorithm. In the second phase of a binary version, this algorithm is used to select features and reduce dimensions. Experiments on CEC functions show that the proposed method has fewer errors than the DE, BBO, SHO, WOA, GOA, and HHO algorithms. In large dimensions such as 200, 500, and 1000 dimensions, the NBO algorithm of meta-heuristic algorithms such as HHO and WOA has a better rank in the optimal calculation of benchmark functions. Experiments show that the proposed algorithm has a greater ability to reduce dimensions and feature selection than similar meta-heuristic algorithms. In 87.5% of the experiments, the proposed method reduces the data space more than other compared methods. 相似文献
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Mitra Jabbari Barat Ali Fakheri Reza Aghnoum Reza Darvishzadeh Nafiseh Mahdi Nezhad Reza Ataei Zahra Koochakpour Mitra Razi 《Food Science & Nutrition》2021,9(3):1761-1779
In the present study, 148 commercial barley cultivars were assessed by 14 AFLP primer combinations and 32 SSRs primer pairs. Population structure, linkage disequilibrium, and genomic regions associated with physiological traits under drought stress were investigated. The phenotypic results showed a high level of diversity between studied cultivars. The studied barley cultivars were divided into two subgroups. Linkage disequilibrium analysis revealed that r2 values among all possible marker pairs have an average value of 0.0178. The mixed linear model procedure showed that totally, 207 loci had a significant association with investigated traits. 120 QTLs out of 207 were detected for traits under normal conditions, and 90 QTLs were detected for traits under drought stress conditions. Identified QTLs after validation and transferring to SCAR markers in the case of AFLPs can be used to develop MAS strategies for barley breeding programs. Some common markers were identified for a particular trait or some traits across normal and drought stress conditions. These markers show low interaction with environmental conditions (stable markers); therefore, selection by them for a trait under normal conditions will improve the trait value under stress conditions, too. 相似文献
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Shiva Golmohammadzadeh Nafiseh Farhadian Amir Biriaee Faranak Dehghani Bahman Khameneh 《Drug development and industrial pharmacy》2017,43(10):1619-1625
Raloxifene hydrochloride (RLX) is a selective estrogen receptor modulator which is orally used for treatment of osteoporosis and prevention of breast cancer. The drug has low aqueous solubility and bioavailability. The aim of the present study is to formulate and characterize oil-in-water microemulsion systems for oral delivery of RLX. To enhance the drug aqueous solubility, microemulsion based on sesame oil was prepared. Sesame oil and Tween 80 were selected as the drug solvent oil and surfactant, respectively. In the first and second formulations, Edible glycerin and Span 80 were applied as co-surfactant, respectively. Pseudo-ternary phase diagrams showed that the best surfactant/co-surfactant ratios in the first and second formulations were 4:1 and 9:1, respectively. The particle size of all free drug-loaded and drug loaded samples were in the range of 31.25?±?0.3?nm and 60.9?±?0.1?nm, respectively. Electrical conductivity coefficient and refractive index of all microemulsion samples confirmed the formation of oil-in-water type of microemulsion. In vitro drug release profile showed that after 24?hours, 46% and 63% of the drug released through the first formulation in 0.1% (w/v) Tween 80 in distilled water as a release medium and phosphate buffer solution (PBS) at pH?=?5.5, respectively. These values were changed to 57% and 98% for the second formulation. Results confirmed that the proposed microemulsion system containing RLX could improve and control the drug release profile in comparison to conventional dosage form. 相似文献
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Ahmad Akbari Nafiseh Ostadmoradi Sayed Majid Mojallali Rostami Maryam Homayoonfal 《化学工程与技术》2017,40(1):76-87
A novel thin‐film composite (TFC) nanofiltration membrane containing hydrophilic organic additives was fabricated via interfacial polymerization. Three organic acids, i.e., lactic, maleic, and citric acid, served as aqueous‐phase additives and their role in membrane structure and nanofiltration membrane flux enhancement was investigated. Fourier transform‐infrared (FT‐IR) analysis confirmed the presence of organic acids in the polyamide (PA) layer. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses were applied to investigate the membrane morphology. The more carboxylic functional groups present in the additive resulted in higher hydrophilicity and porosity and flux was enhanced significantly compared to the neat PA membrane, while salt rejection was influenced only to a minor extent. 相似文献
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Hadi Afrasiabi Garekani Nasim Sanadgol Nafiseh Dehghan Nayyeri 《Drug development and industrial pharmacy》2018,44(3):421-431
Plasticizers play a crucial role in various process of microencapsulation. In this study, the effect of incorporation of plasticizer in process of emulsion solvent evaporation was investigated on properties of ethyl cellulose (EC) microcapsules containing propranolol hydrochloride. The effect of plasticizer type and concentration were investigated on characteristics of microcapsules prepared from different viscosity grades of EC. Product yield, encapsulation efficiency, mean particle size, shape, surface characteristics, solid state of drug, and drug release profiles were evaluated. Product yield and encapsulation efficiency were not dependent on plasticizer type and concentration. However, encapsulation efficiency decreased with increase in EC viscosity grade in the most of the cases. The mean particle size was in the range of 724–797?μm and was not dependent on plasticizer type. Microcapsules formed in the presence of PEG had a very smooth surface with few pores. XRD and DSC studies revealed a reduction of drug crystallinity after microencapsulation especially in presence of PEG. The results showed that the presence of TEC and DEP with different concentrations had no marked effect on drug release from microcapsules containing different viscosity grades of EC. This was not the case when PEG was used, and despite its water solubility it reduced the drug release rate noticeably. The reduction in the drug release in the presence of PEG was concentration-dependent. The use of PEG as a plasticizer in process of emulsion solvent evaporation highly improved the EC microcapsule structure and retarded the drug release rate and therefore is recommended. 相似文献
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Hamed Aghamohammadi Nafiseh Hassanzadeh Reza Eslami-Farsani 《Ceramics International》2021,47(16):22269-22301
Graphene materials, with their distinctively fascinating physicochemical properties, have been receiving great attention as favorable anode materials for use in Li-ion batteries (LIBs). However, the high affinity of graphene nanosheets to restack and agglomerate during electrode assembly reduces the deliverable specific capacity due to the limited available surface area and active sites for Li-ion storage. Furthermore, the high aspect ratio of graphene nanosheets could result in long transport pathways for Li-ions and consequently limiting the rate performance. These drawbacks can be significantly improved via the functionalization of graphene by various heteroatoms and also the formation of porous graphene, adding unique beneficial properties to the inherent characteristics of graphene. Here, a comprehensive review of porous and/or heteroatom doped graphene anode materials for LIBs is presented, which summarizes in detail the main recent literature from their procedure, optimum synthesis parameters, relevant mechanisms, and the obtained morphology/structure to their electrochemical performance as the LIBs anode. Finally, the research gaps are proposed. This review will promote the basic understanding and further development of porous and/or doped graphene materials as anodes for LIBs. 相似文献
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Hosseini Nasab Nafiseh Sharif Farhad Mazinani Saeedeh 《Iranian Polymer Journal》2021,30(10):1053-1061
Iranian Polymer Journal - Uniform dispersion of nanoplatelets in a polymer matrix is always a great concern in the production of high quality nanocomposites. Graphene oxide (GO) was synthesized by... 相似文献