Search results for "Lambert"
showing 7 items of 17 documents
L’alto e puro Maestro. Giuseppe Pitrè vs Lamberto Loria: tre lettere inedite
2017
This paper explores the relationship, contradictory and of intense scientific rivalry, between Giuseppe Pitrè and Lamberto Loria. I will analyze the studies conducted on the subject from Giuseppe Cocchiara up to Sandra Puccini, through the funds of the Historical Archives of the "Giuseppe Pitrè" Ethnographic Museum in Palermo and the National Museum of Popular Arts and Traditions in Rome
Analytical Modeling of the Maximum Power Point with Series Resistance
2021
This paper presents new analytical expressions for the maximum power point voltage, current, and power that have an explicit dependence on the series resistance. An explicit expression that relates the series resistance to well-known solar cell parameters was also derived. The range of the validity of the model, as well as the mathematical assumptions taken to derive it are explained and discussed. To test the accuracy of the derived model, a numerical single-diode model with solar cell parameters whose values can be found in the latest installment of the solar cell efficiency tables was used. The accuracy of the derived model was found to increase with increasing bandgap and to decrease wi…
Conversion of nadir, narrowband reflectance in red and near-infrared channels to hemispherical surface albedo
1997
Abstract Measured nadir-viewed narrow-band reflectanees in red and near infrared channels simulating AVHRR Channels 1 and 2 are compared with measured integrated solar spectrum hemispherical albedos. Reflectanees and albedos were measured from an aircraft over four widely different vegetation surfaces in southeastern Tasmania (Australia). A linear function is used to simultaneously correct for narrow band to broad band conversion errors and to convert nadir viewed reflectances to hemispherical albedos. While the application of the conversion equation presented is limited to the vegetation types of the study, the equation is independent of vegetation type. Results indicate that the reflectan…
La théorie des lignes parallèles de Johann Heinrich Lambert
2014
International audience; The memoir "Theory of parallel lines" (1766) by Johannes Heinrich Lambert is one of the founding texts of hyperbolic geometry, even though his author conceived it as an attempt to show that this geometry does not exist. In fact, Lambert developed that theory with the hope of finding a contradiction. In doing so, he obtained several fundamental results of hyperbolic geometry. This was sixty years before the first writings of Lobachevsky and Bolyai appeared in print. This book contains the first complete translation of Lambert's memoir as well as mathematical and historical commentaries.
Three-dimensional object detection under arbitrary lighting conditions
2006
A novel method of 3D object recognition independent of lighting conditions is presented. The recognition model is based on a vector space representation using an orthonormal basis generated by the Lambertian reflectance functions obtained with distant light sources. Changing the lighting conditions corresponds to multiplying the elementary images by a constant factor and because of that, all possible lighting views will be elements that belong to that vector space. The recognition method proposed is based on the calculation of the angle between the vector associated with a certain illuminated 3D object and that subspace. We define the angle in terms of linear correlations to get shift and i…
Ādas hromoforu kartēšana, izmantojot divu momentuzņēmumu metodi
2018
Darba mērķis ir izstrādāt metodi, ar kuru īsā laika posmā var iegūt informāciju par hromoforu koncentrāciju sadalījumu ādā. Darbā tiek apskatītas vairākas ādas patoloģijas. Katra veidojuma analīzei tiek uzņemti divi attēli. Pirmais attēls tiek iegūts, ādu apgaismojot ar trīs dažādu viļņu garumu lāzeriem: 450nm, 525nm un 850nm. Savukārt otrs attēls tiek iegūts, ādu apgaismojot ar diviem dažādu viļņa garuma lāzeriem: 405nm un 656nm. Tālāk attēli tiek sadalīti R, G un B kanālos. Papildus tiek iegūti pieci references attēli, apgaismojot baltu lapu ar katru no lāzeriem. Sadalot arī šos attēlus R, G un B kanālos, rezultātā tiek iegūti 21 monohromatisks attēls, no kuriem tiek aprēķināti spektrālās…
Computing Difficulties for Deriving Poverty Indices from Some Functional Forms of Lorenz Curves
2014
We examine three families of classical one-parameter functional forms for estimating a Lorenz curve: the power form (Pareto, elementary form), the exponential form (Gupta, elementary form) and fractional form (Rohde). For the first time, we systematically study these functions not for their ability to be estimated but on the point of view of the possibility of deriving poverty indices, which implies first determining the headcount ratio (i.e., the percentage of poor). We show that computing difficulties have been largely underestimated. Two forms, the most simple ones, pose no problem: the elementary power and exponential forms. However, the Pareto functional form poses problem with a restr…