Doctor of Philosophy in Computer Science

dissertationRay tracing is becoming more widely adopted in offline rendering systems due to its natural support for high quality lighting. Since quality is also a concern in most real time systems, we believe ray tracing would be a welcome change in the real time world, but is avoided due to insufficient performance. Since power consumption is one of the primary factors limiting the increase of processor performance, it must be addressed as a foremost concern in any future ray tracing system designs. This will require cooperating advances in both algorithms and architecture. In this dissertation I study ray tracing system designs from a data movement perspective, targeting the various memory resources that are the primary consumer of power on a modern processor. The result is high performance, low energy ray tracing architectures

Fast, effective BVH updates for dynamic ray-traced scenes using tree rotations

technical reportBounding volume hierarchies are a popular choice for ray tracing animated scenes due to the relative simplicity of refitting bounding volumes around moving geometry. However, the quality of such a refitted tree can degrade rapidly if objects in the scene deform or rearrange significantly as the animation progresses, resulting in dramatic increases in rendering times. Existing solutions involve occasional or heuristically triggered rebuilds of the BVH to reduce this effect. In this work, we describe how to efficiently extend refitting with local restructuring operations called tree rotations which can mitigate the effects that moving primitives have on BVH quality by rearranging nodes in the tree during each refit rather than triggering a full rebuild. The result is a fast, lightweight, incremental update algorithm that requires negligible memory, has minor update times and parallelizes easily, yet avoids significant degradation in tree quality or the need for rebuilding while maintaining fast rendering times. We show that our method approaches or exceeds the frame rates of other techniques and is consistently among the best options regardless of the animation scene

Analyza podniku v marginalnich podminkach.

The presenting work analyses the economic and financial situation of agricultural companies farming in less favoured areas - LFA. Due to the width of problems the work is directed towards the mountain and sub-mountain areas (according to the direction N.268/75). The edge of marginality was fixed to 600 meters above the sea level. It is in accordance to the regulations of the EU. The tested sample of companies was further divided into two parts - the edge was 450 meters above the sea level.The data from standard accounting statement and the data from calculations were used for this analysis.Available from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi

Use of the cluster analysis for assessment of economic situation of an enterprise

The aim of the paper was to discuss the disadvantages of enterprises in dry areas compared to enterprises farming in similar production area outside a rain shadow. The analysis was based on the sample of 45 enterprises; twelve of which farming in the area of a rain shadow. In the first step, enterprises were sorted by the cluster analysis into groups farming in the same area, at a similar altitude, with the same structure in a similar manner, and under comparable financial conditions – (such as debt ratio, liquidity and activity ratio). The results of this step showed a different method of farming within enterprises in disadvantaged areas. Such enterprises have created two distinct, separate clusters differing from the average in the use of fixed assets, technical equipment of labour, labour productivity and income structure. In the second step, the way how the return on assets of such enterprises is different from the average profitability of the enterprise was assessed. Testing differences in mean values of profitability was performed using the Student t–test. Due to the high variability of the Return on assets (ROA), the difference between standard and disadvantaged enterprises has not been proved

1 A Mobile Accelerator Architecture for Ray Tracing

Abstract—Mobile computing in the form of smart phones and tablets is becoming ubiquitous. As these devices are being used for increasingly sophisticated tasks, the graphics requirements are also increasing. With the growing desire for highly realistic graphics, the use of ray tracing for rendering will become essential. Ray tracing efficiently models complex illumination effects to improve visual realism in a very different way than current graphics accelerators, which use rasterization on SIMD hardware. Ray tracing also has some intriguing advantages in the mobile computing space where screen pixel counts are not likely to grow significantly, but scene size and complexity will continue to grow. We present a novel multi-core MIMD graphics accelerator architecture that is well suited to ray tracing on mobile platforms. Our architecture provides a large number of floating point resources and exploits thread-level parallelism to keep those units active during ray tracing. We show that a small-footprint version of this architecture is suitable for the mobile computing space, and has performance up to 13 times faster than an existing mobile graphics solution for ray tracing

TRaX: A Multi-Threaded Architecture for Real-Time Ray Tracing

Ray tracing is a technique used for generating highly realistic computer graphics images. In this paper, we explore the design of a simple but extremely parallel, multi-threaded, multi-core processor architecture that performs real-time ray tracing. Our architecture, called TRaX for Threaded Ray eXecution, consists of a set of thread states that include commonly used functional units for each thread and share large functional units through a programmable interconnect to maximize utilization. The memory system takes advantage of the application’s read-only access to the scene database and write-only access to the frame buffer output to provide efficient data delivery with a relatively simple structure. Preliminary results indicate that a multi-core version of the architecture running at a modest speed of 500 MHz already provides real-time ray traced images for scenes of a complexity found in video games. We also explore the architectural impact of a ray tracer that uses procedural (computed) textures rather than image-based (look-up) textures to trade computation for reduced memory bandwidth

Ekonomická efektivnost rostlinné bioprodukce

V metodice je porovnávána ekonomická efektivnost pěstování vybraných plodin (pšenice, žito, tritikale, oves, kukuřice, brambory) z ekologického a konvenčního systému hospodaření. Jsou vyhodnocovány rozdíly ve výnosech plodin v relaci k systému pěstování a faktorům, které tyto rozdíly ovlivňují. V relaci ke standardním technologickým postupům v obou systémech hospodaření jsou stanoveny náklady na plochu i na jednotku produkce a vypočten příspěvek na úhradu. Dále je analyzována struktura nákladů na produkci vybraných plodin, cenové diference mezi konvenční produkcí a bioprodukcí a podíl dotací na příjmech pěstitele