3,459 research outputs found
Associative memory scheme for genetic algorithms in dynamic environments
Copyright @ Springer-Verlag Berlin Heidelberg 2006.In recent years dynamic optimization problems have attracted a growing interest from the community of genetic algorithms with several approaches developed to address these problems, of which the memory scheme is a major one. In this paper an associative memory scheme is proposed for genetic algorithms to enhance their performance in dynamic environments. In this memory scheme, the environmental information is also stored and associated with current best individual of the population in the memory. When the environment changes the stored environmental information that is associated with the best re-evaluated memory solution is extracted to create new individuals into the population. Based on a series of systematically constructed dynamic test environments, experiments are carried out to validate the proposed associative memory scheme. The environmental results show the efficiency of the associative memory scheme for genetic algorithms in dynamic environments
A continuous analogue of the tensor-train decomposition
We develop new approximation algorithms and data structures for representing
and computing with multivariate functions using the functional tensor-train
(FT), a continuous extension of the tensor-train (TT) decomposition. The FT
represents functions using a tensor-train ansatz by replacing the
three-dimensional TT cores with univariate matrix-valued functions. The main
contribution of this paper is a framework to compute the FT that employs
adaptive approximations of univariate fibers, and that is not tied to any
tensorized discretization. The algorithm can be coupled with any univariate
linear or nonlinear approximation procedure. We demonstrate that this approach
can generate multivariate function approximations that are several orders of
magnitude more accurate, for the same cost, than those based on the
conventional approach of compressing the coefficient tensor of a tensor-product
basis. Our approach is in the spirit of other continuous computation packages
such as Chebfun, and yields an algorithm which requires the computation of
"continuous" matrix factorizations such as the LU and QR decompositions of
vector-valued functions. To support these developments, we describe continuous
versions of an approximate maximum-volume cross approximation algorithm and of
a rounding algorithm that re-approximates an FT by one of lower ranks. We
demonstrate that our technique improves accuracy and robustness, compared to TT
and quantics-TT approaches with fixed parameterizations, of high-dimensional
integration, differentiation, and approximation of functions with local
features such as discontinuities and other nonlinearities
VLSI Circuits for adaptive digital beamforming in ultrasound imaging
Cataloged from PDF version of article.For phased-array ultrasound imaging, alternative
beamforming techniques and their VLSI circuits are studied
to form a fully digital receive frontad hardware. In order
to increase the timiig accuracy in beamforming, a computationally
efficient interpolation scheme to increase the sampling
rate is examined. For adaptive beamforming, a phase aberration
correction method with very low computational complexity is
described. Image quality performance of the method is examined
by processing the non-aberrated and aberrated phased-array
experimental data sets of an ultrasound resolution phantom. A
digital beamforming scheme based on receive focusing at the
raster focal points is examined. The sector images of the resolution
phantom, reconstructed from the phased-array experimental
data by beamforming at the radial and raster focal points, are
presented for comparison of the image resolution performances
of the two beamforming schemes. VLSI circuits and their implementations
for the proposed techniques are presented
Antibacterial Predrugs-from 1899 till 2015
The predrug (prodrug) term involves chemically modified inert
compound which upon an administration releases the active parent
drug to elicit its pharmacological response within the body. For many
years, the predrug strategy has been extensively developed to solve
many unwanted drug properties. This approach has several advantages
over conventional drug administration and it has the potential to be
quite effective method for the treatment of diseases in the future. In
this mini-review we describe a number of antibacterial agents‘
predrugs, and the ways by which predrug strategy was exploited to
overcome many pharmaceutical and pharmacokinetic problems that the
parent active antibacterial drugs suffer from such as, low
bioavailability by increasing or decreasing lipophilicity, site selectivity for higher absorption
and less toxicity, short duration of action to increase patient compliance, rapid metabolism to
increase oral bioavailability and masking bitter sensation which is crucial for geriatric and
pediatric patient compliance
Meeting the Mental Health Needs of Syrian Refugees in Turkey
Movements such as the Arab Spring (as described by popular media) and recent regional conflicts have forced people to leave their homes and flee to other countries or regions. Syrian refugees are currently the second largest refugee group worldwide, with half of them resettled in Turkey. Turkish government and non-governmental civil organizations have mobilized efforts to address the immediate survival needs of these refugees such as food, shelter and other provisions. Despite efforts to manage the complexity of mental health and social service needs of forcibly displaced people, counseling services are still lacking. This expository article addresses the mental health needs of Syrian refugees and provides implications for counseling professionals working with displaced people from a crisis intervention approach built on principles and perspectives of humanistic mental health. In addition, programs of support, such as the Mental Health Facilitator program, are discussed
Short-Term International Experiences in Language Teacher Education: A Qualitative Meta-Synthesis
Short-term international experiential learning opportunities can foster language teachers\u27 multidimensional development. Even though such experiences are considered beneficial for language teachers’ development, educational reviews have scarcely concentrated on a comprehensive synthesis of the impact of such experiences on language teachers. This meta-synthesis of qualitative research analyzed the role of international experiential learning in the multidimensional development of pre- and in-service language teachers. Besides presenting a number of research patterns in the literature, this synthesis of 25 qualitative studies reported main outcomes of short-term international experiences for language teachers. These outcomes were synthesized under three main headings: (1) professional, (2) linguistic, and (3) intercultural. Based on this analysis, further research and practice directions regarding international language teacher education emerged. These emerging research agendas concentrated on the critical role of peer circles, host communities, program types and structures, preparation and post-program components, and guidance and supervision
An adaptive speckle suppression filter for medical ultrasound imaging
Cataloged from PDF version of article.An adaptive smoothing technique for speckle suppression in medical B-scan ultrasonic imaging is presented. The technique is based on filtering with appropriately shaped and sized local kernels. For each image pixel, a filtering kernel, which fits to the local homogeneous region containing the processed pixel, is obtained through a local statistics based region growing technique. Performance of the proposed filter has been tested on the phantom and tissue images. The results show that the filter effectively reduces the speckle while preserving the resolvable details. The simulation results are presented in a comparative way with two existing speckle suppression methods. © 1995 IEE
Microestructura de quesos blancos turcos bajos en grasa producidos industrialmente, influencia de la homogenización de la crema
The microstructure and fat globule distribution of reduced and low fat Turkish white cheese were evaluated. Reduced and low fat cheeses were manufactured from 1.5% and 0.75% fat milk respectively which were standardized unhomogenized and homogenized cream in a dairy plant. Homogenized and non-homogenized creams and cheese whey were analyzed for fat globule distribution and cheese samples were also analyzed for microstructure characteristics. According to the results, the homogenization of cream decreased the size of fat globules; and showed that a large number of fat particles were dispersed in the in matrix and improved the lubrication of cheese microstructure. According to the micrographs for the fat, which was not removed, they exhibited a more extended matrix with a few small fat globules compared to the defatted micrographs. Homogenization of cream produces small fat globules and unclustured fat globules were found in the resulting whey. These results are important for dairy processors for using cream homogenization as a processing tool at the industrial level.Se estudia la microestructura y distribución de los glóbulos de grasa de quesos blancos turcos bajos en grasa. Quesos con reducida y baja cantidad en grasa fueron fabricados conteniendo entre el 1,5% y 0,75% de grasa de leche, respectivamente, y con cremas homogeneizadas y no homogeneizadas, en una planta de lácteos. Las cremas homogeneizadas y no homogeneizadas y el suero de los quesos se analizaron para determinar la distribución de los glóbulos de grasa y también se analizaron las características de la microestructura de muestras de queso. De acuerdo con los resultados, la homogeneización de la crema reduce el tamaño de los glóbulos de grasa, mostrando un gran número de partículas de grasa dispersa en la matriz de caseína que mejoró la lubricación de la microestructura del queso. De acuerdo con las micrografías de la grasa que no se elimina, estas exhiben una matriz más amplia en la que hay pocos glóbulos de grasa en comparación con las micrografías de las muestras desgrasadas. La homogenización de la crema produce pequeños glóbulos de grasa y el suero resultante contiene glóbulos de grasa no incrustados. Estos resultados son importantes para los procesadores de productos lácteos, y muestran la utilidad de la homogeneización de crema como una herramienta del procesamiento a nivel industrial
The Biological Activity of Natural Alkaloids against Herbivores, Cancerous Cells and Pathogens
The growing incidence of microorganisms that resist antimicrobials is a constant concern for the scientific community, while the development of new antimicrobials from new chemical entities has become more and more expensive, time-consuming, and exacerbated by emerging drug-resistant strains. In this regard, many scientists are conducting research on plants aiming to discover possible antimicrobial compounds. The secondary metabolites contained in plants are a source of chemical entities having pharmacological activities and intended to be used for the treatment of different diseases. These chemical entities have the potential to be used as an effective antioxidant, antimutagenic, anticarcinogenic and antimicrobial agents. Among these pharmacologically active entities are the alkaloids which are classified into a number of classes, including pyrrolizidines, pyrrolidines, quinolizidines, indoles, tropanes, piperidines, purines, imidazoles, and isoquinolines. Alkaloids that have antioxidant properties are capable of preventing a variety of degenerative diseases through capturing free radicals, or through binding to catalysts involved indifferent oxidation processes occurring within the human body. Furthermore, these entities are capable of inhibiting the activity of bacteria, fungi, protozoan and etc. The unique properties of these secondary metabolites are the main reason for their utilization by the pharmaceutical companies for the treatment of different diseases. Generally, these alkaloids are extracted from plants, animals and fungi. Penicillin is the most famous natural drug discovery deriving from fungus. Similarly, marines have been used as a source for thousands of bioactive marine natural products. In this review, we cover the medical use of natural alkaloids isolated from a variety of plants and utilized by humans as antibacterial, antiviral, antifungal and anticancer agents. An example for such alkaloids is berberine, an isoquinoline alkaloid, found in roots and stem-bark of Berberis asculin P. Renault plant and used to kill a variety of microorganisms
The Biological Activity of Natural Alkaloids against Herbivores, Cancerous Cells and Pathogens
The growing incidence of microorganisms that resist antimicrobials is a constant concern
for the scientific community, while the development of new antimicrobials from new chemical
entities has become more and more expensive, time-consuming, and exacerbated by emerging
drug-resistant strains. In this regard, many scientists are conducting research on plants aiming to
discover possible antimicrobial compounds. The secondary metabolites contained in plants are a
source of chemical entities having pharmacological activities and intended to be used for the treatment
of di erent diseases. These chemical entities have the potential to be used as an e ective antioxidant,
antimutagenic, anticarcinogenic and antimicrobial agents. Among these pharmacologically active
entities are the alkaloids which are classified into a number of classes, including pyrrolizidines,
pyrrolidines, quinolizidines, indoles, tropanes, piperidines, purines, imidazoles, and isoquinolines.
Alkaloids that have antioxidant properties are capable of preventing a variety of degenerative diseases
through capturing free radicals, or through binding to catalysts involved indi erent oxidation
processes occurring within the human body. Furthermore, these entities are capable of inhibiting the
activity of bacteria, fungi, protozoan and etc. The unique properties of these secondary metabolites
are the main reason for their utilization by the pharmaceutical companies for the treatment of di erent
diseases. Generally, these alkaloids are extracted from plants, animals and fungi. Penicillin is the
most famous natural drug discovery deriving from fungus. Similarly, marines have been used as a
source for thousands of bioactive marine natural products. In this review, we cover the medical use of
natural alkaloids isolated from a variety of plants and utilized by humans as antibacterial, antiviral,
antifungal and anticancer agents. An example for such alkaloids is berberine, an isoquinoline
alkaloid, found in roots and stem-bark of Berberis asculin P. Renault plant and used to kill a variety
of microorganisms.Funding: This research received no external funding.
Acknowledgments: Authors are thankful to Basilicata University for supporting the present study
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