The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Lídia Raquel De Carvalho - One of the best experts on this subject based on the ideXlab platform.
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Determination of a point sufficiently close to the asymptote in nonlinear growth functions
Universidade de São Paulo (USP) Escola Superior de Agricultura Luiz de Queiroz (ESALQ), 2011Co-Authors: Mischan, Martha Maria, Sheila Zambello De Pinho, Lídia Raquel De CarvalhoAbstract:Em funções de crescimento que apresentam uma assíntota horizontal superior à curva, frequentemente surge a questão sobre quando se pode considerar o crescimento como praticamente constante, isto é, quando a curva está suficientemente próxima à sua assíntota, de modo que se possa declarar a diferença como sendo não-significativa. Vários métodos têm sido empregados, entre eles o que verifica através do teste t a significância da diferença entre a curva e sua assíntota. O uso de regressão segmentada, como em Portz et al. (2000), também tem esse objetivo, isto é, a determinação de um ponto de início de crescimento praticamente constante. Utilizou-se a função logística de crescimento, a qual possui assíntota horizontal e ponto de inflexão, e aplicou-se um novo método, que consiste na determinação matemática de um ponto da curva a partir do qual a aceleração do crescimento tende assintoticamente a zero. Este método, além de ter um significado biológico, conduz a um ponto bastante próximo aos obtidos pelos métodos anteriormente citados.Growth functions with upper horizontal asymptote do not have a maximum point, but we frequently question from which point growth can be considered practically constant, that is, from which point the curve is sufficiently close to its asymptote, so that the difference can be considered non-significant. Several methods have been employed for this purpose, such as one that verifies the significance of the difference between the curve and its asymptote using a t-test, and that of Portz et al. (2000), who used segmented regression. In the present work, we used logistic growth function, which has horizontal asymptote and one inflection point, and applied a new method consisting in the mathematical determination of a point in the curve from which the growth acceleration asymptotically tends to zero. This method showed the advantage to have biological meaning besides leading to a point quite close to those obtained using the beforementioned methods.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES
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Determination of a point sufficiently close to the asymptote in nonlinear growth functions Determinação de um ponto suficientemente próximo à assíntota em funções de crescimento não lineares
Universidade de São Paulo, 2011Co-Authors: Martha Maria Mischan, Sheila Zambello De Pinho, Lídia Raquel De CarvalhoAbstract:Growth functions with upper horizontal asymptote do not have a maximum point, but we frequently question from which point growth can be considered practically constant, that is, from which point the curve is sufficiently close to its asymptote, so that the difference can be considered non-significant. Several methods have been employed for this purpose, such as one that verifies the significance of the difference between the curve and its asymptote using a t-test, and that of Portz et al. (2000), who used segmented regression. In the present work, we used logistic growth function, which has horizontal asymptote and one inflection point, and applied a new method consisting in the mathematical determination of a point in the curve from which the growth acceleration asymptotically tends to zero. This method showed the advantage to have biological meaning besides leading to a point quite close to those obtained using the beforementioned methods.Em funções de crescimento que apresentam uma assíntota horizontal superior à curva, frequentemente surge a questão sobre quando se pode considerar o crescimento como praticamente constante, isto é, quando a curva está suficientemente próxima à sua assíntota, de modo que se possa declarar a diferença como sendo não-significativa. Vários métodos têm sido empregados, entre eles o que verifica através do teste t a significância da diferença entre a curva e sua assíntota. O uso de regressão segmentada, como em Portz et al. (2000), também tem esse objetivo, isto é, a determinação de um ponto de início de crescimento praticamente constante. Utilizou-se a função logística de crescimento, a qual possui assíntota horizontal e ponto de inflexão, e aplicou-se um novo método, que consiste na determinação matemática de um ponto da curva a partir do qual a aceleração do crescimento tende assintoticamente a zero. Este método, além de ter um significado biológico, conduz a um ponto bastante próximo aos obtidos pelos métodos anteriormente citados
Michael Scott - One of the best experts on this subject based on the ideXlab platform.
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endomorphisms for faster elliptic curve cryptography on a large class of curves
Journal of Cryptology, 2011Co-Authors: Steven D Galbraith, Xibin Lin, Michael ScottAbstract:Efficiently computable homomorphisms allow elliptic curve point multiplication to be accelerated using the Gallant–Lambert–Vanstone (GLV) method. Iijima, Matsuo, Chao and Tsujii gave such homomorphisms for a large class of elliptic curves by working over ${\mathbb{F}}_{p^{2}}$. We extend their results and demonstrate that they can be applied to the GLV method. In general we expect our method to require about 0.75 the time of previous best methods (except for subfield curves, for which Frobenius expansions can be used). We give detailed implementation results which show that the method runs in between 0.70 and 0.83 the time of the previous best methods for elliptic curve point multiplication on general curves.
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endomorphisms for faster elliptic curve cryptography on a large class of curves
International Cryptology Conference, 2009Co-Authors: Steven D Galbraith, Xibin Lin, Michael ScottAbstract:Efficiently computable homomorphisms allow elliptic curve point multiplication to be accelerated using the Gallant-Lambert- Vanstone (GLV) method. We extend results of Iijima, Matsuo, Chao and Tsujii which give such homomorphisms for a large class of elliptic curves by working over ${\mathbb F}_{p^2}$ and demonstrate that these results can be applied to the GLV method. In general we expect our method to require about 0.75 the time of previous best methods (except for subfield curves, for which Frobenius expansions can be used). We give detailed implementation results which show that the method runs in between 0.70 and 0.84 the time of the previous best methods for elliptic curve point multiplication on general curves.
Carvalho, Lídia Raquel De [unesp] - One of the best experts on this subject based on the ideXlab platform.
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Determinação de um ponto suficientemente próximo à assíntota em funções de crescimento não lineares
Universidade de São Paulo (USP) Escola Superior de Agricultura Luiz de Queiroz (ESALQ), 2011Co-Authors: Mischan, Martha Maria [unesp], Pinho, Sheila Zambello De [unesp], Carvalho, Lídia Raquel De [unesp]Abstract:Em funções de crescimento que apresentam uma assíntota horizontal superior à curva, frequentemente surge a questão sobre quando se pode considerar o crescimento como praticamente constante, isto é, quando a curva está suficientemente próxima à sua assíntota, de modo que se possa declarar a diferença como sendo não-significativa. Vários métodos têm sido empregados, entre eles o que verifica através do teste t a significância da diferença entre a curva e sua assíntota. O uso de regressão segmentada, como em Portz et al. (2000), também tem esse objetivo, isto é, a determinação de um ponto de início de crescimento praticamente constante. Utilizou-se a função logística de crescimento, a qual possui assíntota horizontal e ponto de inflexão, e aplicou-se um novo método, que consiste na determinação matemática de um ponto da curva a partir do qual a aceleração do crescimento tende assintoticamente a zero. Este método, além de ter um significado biológico, conduz a um ponto bastante próximo aos obtidos pelos métodos anteriormente citados.Growth functions with upper horizontal asymptote do not have a maximum point, but we frequently question from which point growth can be considered practically constant, that is, from which point the curve is sufficiently close to its asymptote, so that the difference can be considered non-significant. Several methods have been employed for this purpose, such as one that verifies the significance of the difference between the curve and its asymptote using a t-test, and that of Portz et al. (2000), who used segmented regression. In the present work, we used logistic growth function, which has horizontal asymptote and one inflection point, and applied a new method consisting in the mathematical determination of a point in the curve from which the growth acceleration asymptotically tends to zero. This method showed the advantage to have biological meaning besides leading to a point quite close to those obtained using the beforementioned methods
Steven D Galbraith - One of the best experts on this subject based on the ideXlab platform.
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endomorphisms for faster elliptic curve cryptography on a large class of curves
Journal of Cryptology, 2011Co-Authors: Steven D Galbraith, Xibin Lin, Michael ScottAbstract:Efficiently computable homomorphisms allow elliptic curve point multiplication to be accelerated using the Gallant–Lambert–Vanstone (GLV) method. Iijima, Matsuo, Chao and Tsujii gave such homomorphisms for a large class of elliptic curves by working over ${\mathbb{F}}_{p^{2}}$. We extend their results and demonstrate that they can be applied to the GLV method. In general we expect our method to require about 0.75 the time of previous best methods (except for subfield curves, for which Frobenius expansions can be used). We give detailed implementation results which show that the method runs in between 0.70 and 0.83 the time of the previous best methods for elliptic curve point multiplication on general curves.
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endomorphisms for faster elliptic curve cryptography on a large class of curves
International Cryptology Conference, 2009Co-Authors: Steven D Galbraith, Xibin Lin, Michael ScottAbstract:Efficiently computable homomorphisms allow elliptic curve point multiplication to be accelerated using the Gallant-Lambert- Vanstone (GLV) method. We extend results of Iijima, Matsuo, Chao and Tsujii which give such homomorphisms for a large class of elliptic curves by working over ${\mathbb F}_{p^2}$ and demonstrate that these results can be applied to the GLV method. In general we expect our method to require about 0.75 the time of previous best methods (except for subfield curves, for which Frobenius expansions can be used). We give detailed implementation results which show that the method runs in between 0.70 and 0.84 the time of the previous best methods for elliptic curve point multiplication on general curves.
Theodore Mailaender - One of the best experts on this subject based on the ideXlab platform.
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side friction demand versus side friction assumed for curve design on two lane rural highways
Transportation Research Record, 1991Co-Authors: Ruediger Lamm, Elias M Choueri, Theodore MailaenderAbstract:With the objective of exploring whether AASHTO's existing "Policy on Geometric Design of Highways and Streets" provides adequate dynamic safety of driving for new designs, redesigns, and rehabilitation strategies at curved sites, side friction factors on curved sections of two-lane rural highways were investigated. The study was based on geometric design, operating speed, and accident data for 197 curved roadway sections in New York State. To achieve this objective, a comparative analysis of side friction demand versus side friction assumed was carried out. With respect to the independent variable degree of curve, it was determined that (a) friction increases as degree of curve increases; (b) side friction assumed is higher than side friction demand on curves up to about 6.5 deg; (c) for curves greater than 6.5 deg, side friction demand is higher than side friction assumed; and (d) the gap between friction assumed and demand increases with increasing degree of curve. With respect to the independent variable operating speed, it was determined that (a) friction decreases as operating speed increases; (b) side friction assumed is lower than side friction demand up to operating speeds of 50 mph; (c) the gap between side friction assumed and demand increases with decreasing operating speeds; and (d) for operating speeds greater than 50 mph, side friction assumed is higher than side friction demand. With respect to the independent variable accident rate, it was determined that (a) side friction demand begins to exceed side friction assumed when the accident rate is about six or seven accidents per million vehicle-miles and (b) the gap between side friction assumed and demand increases with increasing accident rates. In general, analyses indicated that, especially in the lower design speed classes, which are combined with higher maximum allowable degree of curve classes, there exists the possibility that (a) friction demand exceeds friction assumed and (b) a high accident risk results, because at lower design speed levels the danger exists that design speeds and operating speeds are not well balanced. Thus, it is apparent that driving dynamic safety aspects have an important impact on geometric design, operating speed, and accident experience on curved roadway sections of two-lane rural highways.
