نتایج جستجو برای: derivatives

تعداد نتایج: 104900  

1998
César Silva José Santos-Victor

We address the problem of egomotion estimation of a monocular observer moving with arbitrary translation and rotation in an unknown environment, using log-polar images. The method we propose is uniquely based on the spatio-temporal image derivatives, or the normal ow. Thus, we avoid computing the complete optical ow eld, which is an ill-posed problem due to the aperture problem. We use a search...

2013
Robert Schröck Alexander Sladek Hubert Schmidbaur

Silanes, Silylbenzenes, Di(silyl)benzenes. Bromo(silyl)benzenes 1,2-Di(silyl)benzene (3). has been prepared in a three-step process starting with the reac­ tion of 1 ,2-dibromobenzene and /?-tolyl(chloro)silane with magnesium in tetrahydrofuran, which affords l,2-bis(p-tolylsilyl)benzene (1) as a stable high-yield intermediate. Compound 1 has been converted into 1 .2-bis(trifluoromethanesulfona...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 1990
jabbar khalafy j.m. bruce

several 10-substituted anthralins were readily prepared. their oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone gave the corresponding novel heteroatomic systems. all derivatives were fully characterized by ir, mass and 1hnmr spectroscopy.

Journal: :iranian journal of pharmaceutical research 0
fazel shamsa department of medicinal chemistry, faculty of pharmacy and pharmaceutical sciences research center, tehran university of medical sciences, tehran, iran. alireza foroumadi drug design and development research center, tehran university of medical sciences, tehran, iran. hashim shamsa department of medicinal chemistry, faculty of pharmacy and pharmaceutical sciences research center, tehran university of medical sciences, tehran, iran. nasrin samadi department of drug and food control, faculty of pharmacy, tehran university of medical sciences, tehran, iran. mohammad ali faramarzi department of pharmaceutical biotechnology, faculty of pharmacy, tehran university of medical sciences, tehran, iran. abbas shafiee department of medicinal chemistry, faculty of pharmacy and pharmaceutical sciences research center, tehran university of medical sciences, tehran, iran.

novel analogues of n-piperazinyl fluoroquinolones were prepared and evaluated against a panel of gram-positive and gram-negative bacteria, to study the effect of introducing bulky anthracene and phenanthrene moieties on the antibacterial effects of norfloxacin, ciprofloxacin and gatifloxacin. although most of the novel synthesized compounds had lower antibacterial effects, some derivatives show...

Journal: :CoRR 2017
Daniel Niels Holtmann-Rice Benjamin S. Kunsberg Steven W. Zucker

We develop a linear algebraic framework for the shape-from-shading problem, because tensors arise when scalar (e.g. image) and vector (e.g. surface normal) fields are differentiated multiple times. The work is in two parts. In this first part we investigate when image derivatives exhibit invariance to changing illumination by calculating the statistics of image derivatives under general distrib...

Journal: :The Journal of chemical physics 2014
Yasmine S Al-Hamdani Dario Alfè O Anatole von Lilienfeld Angelos Michaelides

Density functional theory (DFT) studies of weakly interacting complexes have recently focused on the importance of van der Waals dispersion forces, whereas the role of exchange has received far less attention. Here, by exploiting the subtle binding between water and a boron and nitrogen doped benzene derivative (1,2-azaborine) we show how exact exchange can alter the binding conformation within...

2008
Andrea Giachetti Nicola Asuni

In this paper we describe a novel general purpose image interpolation method based on the combination of two different procedures. First, an adaptive algorithm is applied interpolating locally pixel values along the direction where second order image derivative is lower. Then interpolated values are modified using an iterative refinement minimizing differences in second order image derivatives,...

1996
César Silva José Santos-Victor

In this paper, we address the problem of egomotion estimation for a monocular moving observer, under arbitrary translation and rotation. This is a key step for the navigation of any autonomous system. The method we propose is uniquely based on the spatio-temporal image derivatives, and has O(n2) complexity. We search the image for particular geometric properties of the normal flow, tightly conn...

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