839 research outputs found
Rethinking texture mapping
No full textThe intrinsic problems of standard Texture Mapping, regarding UV-maps and seams, are well-known, but often considered unavoidable. In this course we will discuss various radically diferent ways to rethink texture mapping that have been proposed over decades, each ofering diferent advantages and trade-offs
Efficient Adaptive Deferred Shading with Hardware Scatter Tiles
No full textAdaptive shading is an effective mechanism for reducing the number of shaded pixels to a subset of the image resolution with minimal impact on final rendering quality. We present a new scheduling method based on on-chip tiles that, along with relatively minor modifications to the GPU architecture, provides efficient hardware support. As compared to software implementations on current hardware using compute shaders, our approach dramatically reduces memory bandwidth requirements, thereby significantly improving performance and energy use. We also introduce the concept of a fragment pre-shader for programmatically controlling when a fragment shader is invoked, and describe advanced techniques for utilizing our approach to further reduce the number of shaded pixels via temporal filtering, or to adjust rendering quality to maintain stable framerates.Proceedings of the ACM on Computer Graphics and Interactive TechniquesHigh-Performance Rendering3
Quadratic Approximation of Cubic Curves
No full textWe present a simple degree reduction technique for piecewise cubic polynomial splines, converting them into piecewise quadratic splines that maintain the parameterization and C1 continuity. Our method forms identical tangent directions at the interpolated data points of the piecewise cubic spline by replacing each cubic piece with a pair of quadratic pieces. The resulting representation can lead to substantial performance improvements for rendering geometrically complex spline models like hair and fiber-level cloth. Such models are typically represented using cubic splines that are C1-continuous, a property that is preserved with our degree reduction. Therefore, our method can also be considered a new quadratic curve construction approach for high-performance rendering. We prove that it is possible to construct a pair of quadratic curves with C1 continuity that passes through any desired point on the input cubic curve. Moreover, we prove that when the pair of quadratic pieces corresponding to a cubic piece have equal parametric lengths, they join exactly at the parametric center of the cubic piece, and the deviation in positions due to degree reduction is minimized.Proceedings of the ACM on Computer Graphics and Interactive TechniquesRendering Thin or Transparent Objects3
Compacted CPU/GPU Data Compression via Modified Virtual Address Translation
No full textWe propose a method to reduce the footprint of compressed data by using modified virtual address translation to permit random access to the data. This extends our prior work on using page translation to perform automatic decompression and deswizzling upon accesses to fixed rate lossy or lossless compressed data. Our compaction method allows a virtual address space the size of the uncompressed data to be used to efficiently access variable-size blocks of compressed data. Compression and decompression take place between the first and second level caches, which allows fast access to uncompressed data in the first level cache and provides data compaction at all other levels of the memory hierarchy. This improves performance and reduces power relative to compressed but uncompacted data. An important property of our method is that compression, decompression, and reallocation are automatically managed by the new hardware without operating system intervention and without storing compression data in the page tables. As a result, although some changes are required in the page manager, it does not need to know the specific compression algorithm and can use a single memory allocation unit size. We tested our method with two sample CPU algorithms. When performing depth buffer occlusion tests, our method reduces the memory footprint by 3.1x. When rendering into textures, our method reduces the footprint by 1.69x before rendering and 1.63x after. In both cases, the power and cycle time are better than for uncompacted compressed data, and significantly better than for accessing uncompressed data.Proceedings of the ACM on Computer Graphics and Interactive TechniquesHardware Architectures and Space Partitioning3
Hardware-Accelerated Dual-Split Trees
No full textBounding volume hierarchies (BVH) are the most widely used acceleration structures for ray tracing due to their high construction and traversal performance. However, the bounding planes shared between parent and children bounding boxes is an inherent storage redundancy that limits further improvement in performance due to the memory cost of reading these redundant planes. Dual-split trees can create identical space partitioning as BVHs, but in a compact form using less memory by eliminating the redundancies of the BVH structure representation. This reduction in memory storage and data movement translates to faster ray traversal and better energy efficiency. Yet, the performance benefits of dual-split trees are undermined by the processing required to extract the necessary information from their compact representation. This involves bit manipulations and branching instructions which are inefficient in software. We introduce hardware acceleration for dual-split trees and show that the performance advantages over BVHs are emphasized in a hardware ray tracing context that can take advantage of such acceleration.We provide details on how the operations needed for decoding dual-split tree nodes can be implemented in hardware and present experiments in a number of scenes with different sizes using path tracing. In our experiments, we have observed up to 31% reduction in render time and 38% energy saving using dual-split trees as compared to binary BVHs representing identical space partitioning.Proceedings of the ACM on Computer Graphics and Interactive TechniquesHardware Architectures and Space Partitioning3
Learning Complex Policy Distribution with CEM Guided Adversarial Hypernetwork
No full textCross-Entropy Method (CEM) is a gradient-free direct policy search method, which has greater stability and is insensitive to hyperparameter tuning. CEM bears similarity to population-based evolutionary methods, but, rather than using a population it uses a distribution over candidate solutions (policies in our case). Usually, a natural exponential family distribution such as multivariate Gaussian is used to parameterize the policy distribution. Using a multivariate Gaussian limits the quality of CEM policies as the search becomes confined to a less representative subspace. We address this drawback by using an adversarially-trained hypernetwork, enabling a richer and complex representation of the policy distribution. To achieve better training stability and faster convergence, we use a multivariate Gaussian CEM policy to guide our adversarial training process. Experiments demonstrate that our approach outperforms state-of-the-art CEM-based methods by 15.8% in terms of rewards while achieving faster convergence. Results also show that our approach is less sensitive to hyper-parameters than other deep-RL methods such as REINFORCE, DDPG and DQN.Interactive Intelligenc
"Kitâb-ı Cem Sultân" and Southwestern Europe
No full textAnonim bir eser olan “Kitâb-ı Cem Sultân” Cem Sultan’ın hayatı, Osmanlı ve Batı arasındaki siyasal ve diplomatik ilişkiler ve yazann seyahati esnasında gördüğü yerlerdeki bazı ilginç gelenekler ile ilgili bilgiler ihtiva eder. Dolayısı ile bu eser Avrupa ile Osmanlı arasındaki diplomatik, siyasi ve kültürel ilişkiler bakımından önemlidir. Eserin bahsi geçen yönlerine bağlı olarak bu çalışmada Kâfir imajı, bölge insanının kültürü, gelenekleri ve iki kültürün karşılıklı bakış açılan İncelenmektedir.“Kitâb-ı Cem Sultân” is an anonymous book, contains information about Cem Sultan’s life and politic\diplomatic relations betvveen Ottoman and the Westem Europe. A part from these it has data of culture and tradition of regions which was seen by author. Indirectly it is important from cultural and politics relation point of view. According to these ways of text, in this study, infidel image in the Turkish people and their interesting against Europe culture and Christian faith were examined
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Coilgun Structures
No full textResearch on coilguns at the Center for Electromechanics at the University of Texas at Austin (CEM-UT) has yielded considerable insight into the optimal design of coilgun structures. This research has indicated that the structural requirements are strong functions of launcher classification as well as acceleration mode. As a result, CEM-UT has built and tested the DC coaxial accelerator (DCA) coilgun, which is a multistage pulsed induction launcher that makes extensive use of composite material technology. The author presents analytical techniques (closed-form and numerical) used to make structural design calculations in the DCA launcher. The evolution of the multiturn wound DCA armature design is discussed. In addition, measured plastic deformation of this armature after a high-energy experiment is compared to that predicted by finite element analysisCenter for Electromechanic
The unlucky life story of Cem Sultan in Câm-ı Cem-âyîn and his new poems
No full textBu çalıĢmada, Bayatî‟nin Câm-ı Cem-âyîn adlı eserindeki Cem Sultan‟a
ait hasb-i hâl türü Ģiirler üzerinde durulmuĢtur. ÇalıĢmanın amacı eserden
yola çıkarak Ģairin hayatı, kiĢiliği, Ģiirleri ve dönemi hakkında bilinmeyenleri
ortaya koymaktır. ÇalıĢma, ġehzâde Cem (ö. 900/1495) ve Hasan Bayatî (ö.
900/1495‟te sağ) arasında Kâbe‟de Ģiirle baĢlayan dostluğu; Câm-ı Cem-âyîn
adlı eserin yazılıĢ sebebi, konusu, önemi ve neĢrini içermektedir. Bu
çalıĢmayla, Cem‟in Türkçe divanında yer almayan iki Ģiiri incelenmiĢ olup
hem bu Ģiirlerden hem de Ali Emîrî‟nin tespitlerinden yola çıkılarak Cem
Sultan‟a dair yeni bilgilere ulaĢılmıĢtır. Türk-Osmanlı neslinin öz tarihçesi
olan Câm-ı Cem-âyîn, Bayatî ve özellikle Cem Sultan‟ın hayat ve kiĢiliğine
dair önemli bilgiler içermesi bakımından oldukça önemli bir eserdir. ÇalıĢma
giriĢ, iki bölüm, sonuç ve kaynakçadan oluĢmaktadır. GiriĢ bölümünde, Câmı Cem-âyîn‟i eski harflerle neĢreden Ali Emîrî‟nin ön sözü ve eserin
dîbâcesindeki bilgiden hareketle eser ve müellifi hakkında bilgi verilmiĢ,
sonra adı geçen eserin Ģekil, içerik ve yayın bilgisi üzerinde durulmuĢtur.
Birinci bölümde, iki farklı eserden Cem‟in hayatına dair yeni bilgiler
aktarılmıĢ, Bayatî‟nin Farsça bir gazeli ve bu gazele Cem Sultan tarafından
yazılan Türkçe bir nazire gazel incelenmiĢtir. Ġkinci bölümde, Câm-ı Cemâyîn‟in hatime bölümünde yer alan ve çalıĢmamıza konu olan tarihî bir
“tahmisnâme” Ģekil, içerik, dil ve anlatım özellikleri yönünden incelenmiĢtir.
Hasb-i hâl türündeki bu önemli manzumenin tam metni, dil içi çevirisi ve
notlarla birlikte verildikten sonra sonuç ve kaynakça yazımıyla çalıĢma
tamamlanmıĢtır.This study focuses on Cem Sultan‟s poems written in the tone of friendly
chat included in the book Câm-ı Cem-âyîn by Bayatî. The study aims to
reveal what is unknown about the poet‟s life, personality, poems and his era.
This study is concerned with friendship between Prince Cem (date of death
900/1495) and Hasan Bayatî (date of death 900/1495 in life) which started in
Kaaba, the reason why the book “Câm-ı Cem-âyîn” was written, its
importance and publication. This current study analyses two poems of Cem
Sultan which are not included in his Turkish Collection of Poems, and makes
explorations about Cem Sultan by setting out from these two poems and from
the findings obtained by Ali Emîrî. Câm-ı Cem-âyîn, a short history of Ottoman Turks lineage, is a very important work in that it includes
information on Bayatî‟s and especially Cem Sultan‟s life and personality.
The study consists of introduction, two chapters, conclusion and a chapter
about bibliography. In the introduction part the preface written by Ali Emîrî,
information about the work based on the preface, and about the author is
presented and then information on the form, content and publication of the
book is offered. In Chapter One information about Cem Sultan‟s life is given
based on two different studies, and a lyric poem (gazal) written by Bayatî in
Persian language and a poem written by Cem Sultan in parallel to Bayatî‟s
gazal in Turkish language (nazire gazal) are also analysed in this chapter. In
Chapter Two a historical “tahmisnâme”, which is included in the epilogue of
Câm-ı Cem-âyîn and which is the subject matter of this study is analysed in
terms of form, content, and linguistic and stylistic properties. Having
paraphrased the full text of this important poem- which is in the tone of
friendly chat- with explanatory notes, the book reaches the conclusion and
ends with bibliography giving references
Method for sample preparation for cryoelectron microscopy (CEM) microreactor and loading platform
No full textA method for sample preparation for cryoelectron microscopy (CEM), wherein the sample is held in a microreactor, wherein the conditions in the microreactor are regulated relative to the environment, wherein the sample in the microreactor is frozen according to a quench freeze process, whereupon the sample, in frozen condition, is placed in the electron microscope. A microreactor for use with cryoelectron microscopy (CEM), comprising a first and second membrane, which membranes, at least in a condition of use, enclose a chamber, while the membranes are configured to last until at least the beginning of a quench freeze process.Applied Science
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