Des nouvelles courbes de polarisation et de radiances en fonction de l’angle de diffusion sont étudiées à _ = 632,8 nm et 543,5 nm en utilisant des instruments PROGRA2 (Propriétés Optiques des GRains Astronomiques et Atmosphériques) pour différents types d'échantillons de suie et de noir de carbone en lévitation dans l’air et déposés sur une surface. Les échantillons de suie sont produits dans des conditions de combustion différentes, affectant ainsi leurs propriétés morphologiques. Un générateur de suie a été également utilisé pour étudier des suies ‘jeunes’ émises par la combustion du propane. Une comparaison des propriétés optiques entre les suies en lévitation et déposées sur une surface a été discutée. Enfin, ces courbes sont comparées à celles produites par différents types de sable. Les amplitudes de polarisation produites par la suie diffèrent en fonction du diamètre des particules primaires et de la distribution en taille. Ces courbes seules sont donc insuffisantes pour estimer la nature des agglomérats solides qui pourraient être détectés par des mesures à distance dans la stratosphère. D'autre part les courbes de radiance produites par ces échantillons montrent un comportement différent de celles produites par les échantillons de sable et par la poussière interplanétaire. Il est donc important lors de l'interprétation des mesures stratosphériques de combiner les courbes de radiances avec les courbes de polarisation pour déterminer la nature des agglomérats et de fournir des informations sur la nature de suie détectée telle que la taille des particules primaires ainsi que la distribution en taille. / New polarization and brightness curves as function of scattering angle are studied at _= 632.8 nm and 543.5 nm using PROGRA2 instruments (Propriétés Optiques des Grains Astronomiques et Atmosphériques) for different kinds of soot samples and carbon-black samples levitating in a cloud and deposited on a surface. The soot samples are generated under different combustion conditions, thus affecting their optical properties. A soot generator was also used to study fresh samples issued from propane combustion. A comparison between soot levitating on a cloud and deposited on surface was discussed. Finally these curves are compared to those produced by different kind of sand. The amplitudes of polarization produced by soot differ significantly depending on the primary particle diameter and on size distribution. These curves alone are then not sufficient to estimate the nature of the solid agglomerates that could be detected by remote measurements in the stratosphere. On the other hand the curves of brightness produced by these samples show a behavior different from those produced by the sand samples and that produced by interplanetary dust. It is therefore important in the interpretation of stratospheric measurements to combine the brightness with the polarization curves to identify the nature of the agglomerates and to provide information on the nature of soot detected as the primary particle diameter and size distribution.

No / Rendering packages are used by visual psychophysicists to produce complex stimuli for their experiments, tacitly assuming that the simulation results accurately reflect the light-surface interactions of a real scene. RADIANCE is a physically based, freely available, and commonly used rendering software. We validated the calculation accuracy of this package by comparing simulation results with measurements from real scenes. RADIANCE recovers color gradients well but the results are shifted in color space. Currently, there is no better simulation alternative for achieving physical accuracy than by combining a spectral rendering method with RADIANCE.

No / Visual psychophysicists, who study object, color, and light perception, have a demand for software that produces complex but, at the same time, physically accurate stimuli for their experiments. The number of computer graphic packages that simulate the physical interaction of light and surfaces is limited, and mostly they require the purchase of a license. RADIANCE (Ward, 1994), however, is freely available and popular in the visual perception community, making it a prime candidate. We have shown previously that RADIANCE¿s simulation accuracy is greatly improved when color is coded by spectra, rather than by the originally envisaged RGB triplets (Ruppertsberg & Bloj, 2006). Here, we present a method for spectral rendering with RADIANCE to generate hyperspectral images that can be converted to XYZ images (CIE 1931 system) and then to machine-dependent RGB images. Generating XYZ stimuli has the added advantage of making stimulus images independent of display devices and, thereby, facilitating the process of reproducing results across different labs. Materials associated with this article may be downloaded from www.psychonomic.org.

Simulated Landsat reflectance spectra of soil samples were compared to actual Landsat radiance values of soils in two fields (1 and 3) near Vance, Mississippi. The simulated reflectance spectra were calculated by combining Landsat spectral sensitivity with laboratory-based spectrophotometer reflectance values. The actual radiance data were obtained by extracting pixel values from Landsat images. Simple linear regression (SLR) yielded significant linear relationships for 1997 field-1 and 2001 field-3 data. Multiple linear regression (MLR) and weighted linear regression (WLR), which indirectly accounted for moisture content and spatial resolution, respectively, yielded improvement in R2 for most of the studied bands. The analyses generally satisfied the normality and constant variance assumptions, and removal of outliers improved the validity of the assumptions and R2. It was concluded that indirect measures of soil moisture content and spatial uncertainty can substantially improve the relationship between remotely sensed bare-soil spectra and laboratory spectra.

ABSTRACT Professor Peter Steele S.J. cuts a fascinating figure both in contemporary scholarship and poetic achievement. His work extends over a vast range of genre from poetry to criticism, public address and intellectual journalism. Some of his huge literary output is published, some of it awaits publication, and much of it is either uncollected or held in archival situations. Steele is a writer who matters today not only by virtue of his leading a distinguished academic career, and being a widely published poet, but also because for some two decades he has been a focal figure in the Society of Jesus in Australia and New Zealand and has had extensive experience as he would say 'plying his priesthood' in various British and American Jesuit institutions. This has resulted in a large volume of mostly unpublished writings ranging from prayers, liturgies and reflections to homilies for private and public occasions. The challenge of addressing Steele�'s literary achievement lies in the fact that his spiritual insights form the basis of his poetic, academic, and ethical imagination. This thesis has attempted to identify the core nature of these insights and to trace the way in which they ramify into the world of people, events, and art, especially literature. The basic issue concerns the principle of radiance, how it finds expression through Steele�s major motifs or figures of Jester, Pilgrim Expatriate, Celebrant and Word or Witness, and how this principal operates as the unifying basis of his thought. The thesis tries to investigate this unifying vision within the subtle diversity of the many ways Steele encounters the modern world. In identifying Steele�s structure of thought as a radiant entity focused on the theocentre of God and emanating to the Incarnate God, to the writers of the gospels and epistles, to St. Ignatius, to St. Edmund Campion and to all people especially artists, it has been necessary to shape each chapter in a roughly parallel manner and to organise it according to these stratafications. Each chapter places the individual motif within Steele�'s individual and Ignatian milieux, and examines the function of the particular figure or motif under investigation. Each chapter will then trace the figure (Fool, Pilgrim / Expatriate, Celebrant or Word Witness), as Steele sees it manifest in God, in Christ, in the scriptures, and as he understands it imparted to Campion, to Ignatius as he writes the Spiritual Exercises and to writers (and readers) of literature. Each chapter also has variations appropriate to its subject matter and medium so that for instance the chapter treating Steele�s Pilgrim figure will consider his treatment of it in both p oetics and homiletics and that treating the Word or Witness will predominantly relate to that figure to his critical appraisal of Peter Porter�s p oetry and the organisation of the latter will break from the established pattern of organisation in several major ways. This thesis offers a study of a rich Australian talent operating intellectually, academically, imaginatively and spiritually. If one were to seek to place Steele amongst similarly minded writers one would have to locate him in the community of writers recognised for their classical and contemporary sophistication, writers such as Peter Porter, Seamus Heaney, Joseph Brodsky, Derek Walcott and Anthony Hecht. In this sense Steele is international rather than Australian in his emphasis; but being a true international he also includes Australia in his thinking.

ABSTRACT Professor Peter Steele S.J. cuts a fascinating figure both in contemporary scholarship and poetic achievement. His work extends over a vast range of genre from poetry to criticism, public address and intellectual journalism. Some of his huge literary output is published, some of it awaits publication, and much of it is either uncollected or held in archival situations. Steele is a writer who matters today not only by virtue of his leading a distinguished academic career, and being a widely published poet, but also because for some two decades he has been a focal figure in the Society of Jesus in Australia and New Zealand and has had extensive experience as he would say 'plying his priesthood' in various British and American Jesuit institutions. This has resulted in a large volume of mostly unpublished writings ranging from prayers, liturgies and reflections to homilies for private and public occasions. The challenge of addressing Steele�'s literary achievement lies in the fact that his spiritual insights form the basis of his poetic, academic, and ethical imagination. This thesis has attempted to identify the core nature of these insights and to trace the way in which they ramify into the world of people, events, and art, especially literature. The basic issue concerns the principle of radiance, how it finds expression through Steele�s major motifs or figures of Jester, Pilgrim Expatriate, Celebrant and Word or Witness, and how this principal operates as the unifying basis of his thought. The thesis tries to investigate this unifying vision within the subtle diversity of the many ways Steele encounters the modern world. In identifying Steele�s structure of thought as a radiant entity focused on the theocentre of God and emanating to the Incarnate God, to the writers of the gospels and epistles, to St. Ignatius, to St. Edmund Campion and to all people especially artists, it has been necessary to shape each chapter in a roughly parallel manner and to organise it according to these stratafications. Each chapter places the individual motif within Steele�'s individual and Ignatian milieux, and examines the function of the particular figure or motif under investigation. Each chapter will then trace the figure (Fool, Pilgrim / Expatriate, Celebrant or Word Witness), as Steele sees it manifest in God, in Christ, in the scriptures, and as he understands it imparted to Campion, to Ignatius as he writes the Spiritual Exercises and to writers (and readers) of literature. Each chapter also has variations appropriate to its subject matter and medium so that for instance the chapter treating Steele�s Pilgrim figure will consider his treatment of it in both p oetics and homiletics and that treating the Word or Witness will predominantly relate to that figure to his critical appraisal of Peter Porter�s p oetry and the organisation of the latter will break from the established pattern of organisation in several major ways. This thesis offers a study of a rich Australian talent operating intellectually, academically, imaginatively and spiritually. If one were to seek to place Steele amongst similarly minded writers one would have to locate him in the community of writers recognised for their classical and contemporary sophistication, writers such as Peter Porter, Seamus Heaney, Joseph Brodsky, Derek Walcott and Anthony Hecht. In this sense Steele is international rather than Australian in his emphasis; but being a true international he also includes Australia in his thinking.

In this thesis is evaluated the xylem structure of Norway spruce needles depending on solar radiation and altitude. Same-age spruce stand has been selected on the area of Hruby Jesenik at different altitudes on the southern and northern exposure. Sun needle samples were taken on each stand. The analysis of xylem structure was done. The number of tracheids, tracheid diameter, tracheid area and xylem area were evaluated. It was found that more than 50% dependence of xylem parameters on altitude and solar radiation, where exposure significantly affects the xylem structure only at altitudes above 1 200 m. The prediction maps show that the highest values of predicted xylem parameter values are found between 800 m and 1200 m about sea level.

This diploma thesis deals with system for visible light communication (VLC). There are described basic optical elements like a electroluminescence diode and photodiode. In next chapter is described design of transmitter, optical channel and receiver. Attention is also devoted to modulation suitable for optical communication. The last chapter is devoted to program in Matlab language, which's name is Program for calculation of optical intensity distribution. That program was created in this diploma theses.

The growing demand for realistic renderings in both film and games has led to a number of proposed solutions to the Global Illumination problem. In order to imitate natural lighting, it is necessary to gather indirect illumination of the surrounding environment for lighting computations. This is a computationally expensive problem, requiring the sampling or rasterization of the hemisphere surrounding each ray intersection, to which there is no standardized solution. In this thesis we propose a new method of approximation using environment maps for caching radiance. The proposed method leverages a voxelized scene representation for storing direct illumination and a cache of environment maps for integrating indirect illumination. By using a voxelized scene to gather indirect lighting contributions and caching these contributions spatially, we are able to achieve fast and convincing renders of large complex scenes. The result of our implementation produces images comparable to those of existing Monte Carlo integration methods with render speeds a magnitude or more faster.

No description available.