waashk/acm huggingface dataset:
an axiomatic treatment of three qualitative decision criteria  the need for computationally efficient decision-making techniques together with the desire to simplify the processes of knowledge acquisition and agent specification have led various researchers in artificial intelligence to examine qualitative decision tools. however, the adequacy of such tools is not clear. this paper investigates the foundations of  maximin, minmax regret, and competitive ratio, three central qualitative decision criteria, by characterizing those behaviors that could result from their use. this characterizaton provides two important insights: (1)under what conditions can we employ an agent model based on these basic qualitative decision criteria, and (2) how "rational" are these decision procedures. for the competitive ratio criterion in particular, this latter issue is of central importance to our understanding of current work on on-line algorithms. our main result is a constructive representation theorem that uses two choice axioms to characterize maximin, minmax regret, and competitive ratio.  ronen i. brafman moshe tennenholtz
the radiance lighting simulation and rendering system  this paper describes a physically-based rendering system tailored to the demands of lighting design and architecture. the simulation uses a light- backwards ray- tracing method with extensions to efficiently solve the rendering equation under most conditions. this includes specular, diffuse and directional-diffuse reflection and transmission in any combination to any level in any environment, including complicated, curved geometries. the simulation blends deterministic and stochastic ray-tracing techniques to achieve the best balance between speed and accuracy in its local and global illumination methods. some of the more interesting techniques are outlined, with references to more detailed descriptions elsewhere. finally, examples are given of successful applications of this free software by others.  gregory j. ward
lossless compression of computer generated animation frames  this article presents a new lossless compression algorithm for computer animation image sequences. the algorithm uses transformation information available in the animation script and floating point depth and object number information at each pixel to perform highly accurate motion prediction with vary low computation. the geometric data (i.e., the depth and object number) can either be computed during the original rendering process and stored with the image or computed on the fly during compression and decompression. in the former case the stored geometric data are very efficientlycomporessed using motion prediction and a new technique called direction coding, typically to 1 to 2 bits per pixel. the geometric data are also useful in z-buffer image compsiting and this new compression algorthm offers a very low storage overhead method for saving the information needed for this comoositing. the overall compression ratio of the new algorithm, including the geometic data overhead, in compared to conventional spatial linear prediction compression and block-matching motion. the algorithm improves on a previous motion prediction algorithm by incorporating block predictor switching and color ratio predition. the combination of thes techniques gives compression ratios 30% better than those reported previously.  hee cheol yun brian k. guenter russell m. mersereau
a core graphics environment for teletext simulations  the development of our graphics environment over the past year has been directed towards demonstrating the concept of broadcast teletext service, where pages of graphics and text are received in the home over existing television channels. we have developed a graphics editor, radix, which uses an underlying core graphics package to create teletext-compatible images. radix is also used to display these images at arbitrary resolutions by scaling the graphics primitives, selecting the corresponding sizes of fonts and bitmaps, and then precisely adjusting the output video signal. the combination of powerful display hardware and a robust set of software tools has allowed us to rapidly prototype potential teletext features, and to provide these accurate simulations of teletext pages at any resolution. while this general graphics environment does impose some inefficiencies in running graphics applications, they are far outweighed by the ability to quickly respond to changing requirements.  douglas f. dixon
natural language processing in a japanese text-to-speech system  a japanese text-to-speech system is developed that provides continuous generation of natural speech from newspaper articles and other japanese texts written in an unrestricted mixture of kanji (ideograms. --- 7000 chinese characters), kana (two types of phonograms, --- 200 characters), alphanumerics and marks (including , &, $, etc.).  in the newly developed system, the japanese texts are analyzed in terms of both grammar and meaning where texts have ambiguities, but in terms of grammar only where there is no ambiguity. the dictionary in this system contains ordinarily segmented words for various open texts and special compound words, most of which are proper nouns that have multiple readings when segmented. this reduces the percentage of erroneous readings from 2.2% for the conventional method to 0.2% and of erroneous accentuation from 20% to 5%.  the dictionary containing approximately 430,000 words uses a resident index consists of the first two characters of the words. this approach for accessing is adopted because many japanese words consists of two basic characters. this improved the systems efficiency in maintaining a higher level of accuracy.  these improvements will provide advanced information exchanges to subscriber networks.  yoshifumi ooyama masahiro miyazaki satoru ikehara
techniques for interactive raster graphics  the visual quality of raster images makes them attractive for applications such as business graphics and document illustration. such applications are most fully served using interactive systems to describe curves, areas and text which can be rendered at high resolution for the final copy. however, to present such imagery in an interactive environment for moderate cost is difficult. techniques are presented that provide solutions to the problems of scan conversion, screen update, and hit testing for a class of interactive systems called illustrators. the design rests on the use of software display file encoding techniques. these ideas have been used in the implementation of several illustration programs on a personal minicomputer.  patrick baudelaire maureen stone
model validation: with respect to the user  saul i. gass:  the utility of a simulation model to a specific user depends on the user's ability to interpret available model documentation into a "measure" of model confidence. we shall review an approach to the obtaining of such a measure and the distinct, but interrelated roles of the user and analyst.  robert g. sargent:  a summary of the use of hypothesis testing and confidence intervals for validating models of observable systems will be presented. the presentation will include topics such as model accuracies, cost of data collection, model user's risk, model builder's risk, and acceptable validity range.  j. william schmidt:  in my view validation is the process of determining whether or not the system model describes the behavior of the system modeled with fidelity adequate for effective use of the model for its intended purpose(s). at best, a model is only an approximate representation of the reality described by the model. hence an attempt to describe system behavior through a model carries with it the implicit assumption that at least minimal discrepancy between model and system behavior is tolerable with respect to the intended purpose of the model. the discrepancy between model and system behavior is usually referred to as model error (a more descriptive reference would be model errors since errors may exist in many dimensions). the process of validation may then be viewed as the attempt to determine the magnitude of model error and whether or not the error exhibited by the model falls within limits which will permit effective use of the model.  robert g. sargent saul i. gass j. william schmidt
bumps: a program for animating projections  bumps (brown university multiple projection system) is a program that illustrates the implementation of viewing transformations using animation. the program uses the viewing model defined in the core graphics system. bumps employs interactive computer graphics to demonstrate how planar geometric projections are generated, what the effects of different projections and projection parameters are on the projected object, and how the viewing functions of the core graphics system work. after presenting background material on projections, the features of bumps are described, followed by a pictorial user scenario of bumps in action. the paper concludes with a discussion of the merits of user controlled animation for teaching and possible improvements to the program.  robert f. gurwitz richard w. thorne andries van dam ingrid b. carlbom
three-dimensional object recognition  a general-purpose computer vision system must be capable of recognizing three- dimensional (3-d) objects. this paper proposes a precise definition of the 3-d object recognition problem, discusses basic concepts associated with this problem, and reviews the relevant literature. because range images (or depth maps) are often used as sensor input instead of intensity images, techniques for obtaining, processing, and characterizing range data are also surveyed.  paul j. besl ramesh c. jain
texture compression with adaptive block partitions (poster session)  we present image compression method based on block palletizing. image block is partitioned into four subsets, and each subset is palletized by 2 or 4 colors from the quasioptimal local palette, constructed for the whole block. index map for the whole block, being the union of index maps for subsets, is thus only 1 or 2 bits deep, while the local palette may consist of 8 or even 16 colors. the local palette has a specific geometrical configuration in rgb color space, determined by only 2 colors. these two colors are stored explicitly, and the rest are reconstructed at the decompression stage. compressed block consists, essentially, of the index map, palette description and partition description. this format allows fast access to randomly chosen pixels, and high reconstruction quality for compression ratios from 8 to 12, which is useful for texture storage in 3d graphics applications where real- time _decompression_ is crucial.  leonid levkovich- maslyuk pavel kalyuzhny alexander zhirkov
biif, vrml and cgm this edition of the standards pipeline consists of three articles that provide an in-depth look at applications of three important international standards. in the first article, bernadette kuzma of semcor, inc. describes the basic image interchange format (biif) formally known as iso/iec 12087-5:1998. while biif originated in the defense community, it is beginning to find wider applications in areas ranging from electronic libraries to medical imaging. in the second article, richard f. puk of intelligraphics describes the current status and future prospects for the virtual reality modeling language (vrml) formally known as iso/iec 14772-1. in the final article, lofton henderson of inso corporation and john gebhardt of intercap graphics systems, inc. describe the work of the cgm open consortium and in particular the webcgm profile. bernadette kuzma george s. carson richard f. puk john gebhardt
visfiles: presentation techniques for time-series data this is the first in a series of columns on the subject of data visualization. i'm excited to have this opportunity because it will give me an excuse to finally learn about some subjects that i've wanted to learn about but never gave myself the time. gordon cameron, _computer graphics_ editor, has given me some latitude on topics so future visualization columns will deal with color selection, data visualization systems and apis, data visualization research, information visualization, user interface issues, tips and hints, etc. if you have comments on this column or suggestions for future columns, please send me email _(todd@acm.org)._in this issue i will give an overview of some familiar, and some probably unfamiliar, time-series data presentation techniques. time- series data visualization is becoming an increasingly important topic as data archives grow exponentially and computing becomes ubiquitous. some researchers claim that time-series data can be imaged using techniques similar to those applied to spatial data (since time is most often linear), and some claim that temporal data is a much different beast. for example, temporal data can have multiple strands and events, features not present in spatial data. there are also many interesting unsolved problems and data handling issues associated with temporal data: boolean and other mathematical operations data storage and temporal databases data query and retrieval data generalization (handling data at vastly different resolutions) data models and representation data presentationi have lately been working on designing a user interface for a simple geographic information system capable of manipulating and compositing time-series geo-referenced data. this project started me thinking about the different ways of visually representing temporal data. without going into much detail on any one method, following are all the methods i could find within arms length in my office. most of these methods allow the scientist or visualizer to present the time-series in a single image, while the final method uses an animation technique. good techniques for visually presenting time-series data will: reveal spatial and temporal relationships uncover patterns show variability t. todd elvins
on visible surface generation by a priori tree structures  this paper describes a new algorithm for solving the hidden surface (or line) problem, to more rapidly generate realistic images of 3-d scenes composed of polygons, and presents the development of theoretical foundations in the area as well as additional related algorithms. as in many applications the environment to be displayed consists of polygons many of whose relative geometric relations are static, we attempt to capitalize on this by preprocessing the environment's database so as to decrease the run-time computations required to generate a scene. this preprocessing is based on generating a "binary space partitioning" tree whose in order traversal of visibility priority at run-time will produce a linear order, dependent upon the viewing position, on (parts of) the polygons, which can then be used to easily solve the hidden surface problem. in the application where the entire environment is static with only the viewing-position changing, as is common in simulation, the results presented will be sufficient to solve completely the hidden surface problem.  henry fuchs zvi m. kedem bruce f. naylor
illumination in diverse codimensions  this paper considers an idealized subclass of surface reflectivities; namely a simple superposition of ideal diffuse and ideal specular, restricted to point light sources. the paper derives a model of diffuse and specular illumination in arbitrarily large dimensions, based on a few characteristics of material and light in 3-space. it describes how to adjust for the anomaly of excess brightness in large codimensions. if a surface is grooved or furry, it can be illuminated with a hybrid model that incorporates both the id geometry (the grooves or fur) and the 2d geometry (the surface).  david c. banks
visualizing multivalued data from 2d incompressible flows using concepts from painting  we present a new visualization method for 2d flows which allows us to combine multiple data values in an image for simultaneous viewing. we utilize concepts from oil painting, art, and design as introduced in [1] to examine problems within fluid mechanics. we use a combination of discrete and continuous visual elements arranged in multiple layers to visually represent the data. the representations are inspired by the brush strokes artists apply in layers to create an oil painting. we display commonly visualized quantities such as velocity and vorticity together with three additional mathematically derived quantities: the rate of strain tensor (defined in section 4), and the turbulent charge and turbulent current (defined in section 5). we describe the motivation for simultaneously examining these quantities and use the motivation to guide our choice of visual representation for each particular quantity. we present visualizations of three flow examples and observations concerning some of the physical relationships made apparent by the simultaneous display technique that we employed.  r. m. kirby h. marmanis d. h. laidlaw
eliminating the boundary effect of a large-scale personal communication service network simulation  eliminating the boundary effects is an important issue for a large-scale personal communication service (pcs) network simulation. a pcs network is often modeled by a network of hexagonal cells. the boundary may significantly bias the ouput statistics if the number of hexagonal cells is small in a pcs network simulation. on the other hand, if the simulation is to be completed within a reasonable time on the available computing resources, the number of cells in the simulation cannot be too large. to avoid the inaccuracy caused by the boundary effect for a pcs network simulation with limited computing resources, we propose wrapping the hexagonal mesh into a homogeneous graph (i.e., all nodes in the graph are topologically identical). we show that by using the wrapped hexagonal mesh, the inaccuracy of the output measures can be limited even though the number of cells in the simulation is small. we can thus obtain the same statistical accuracy while using significantly less computation power than required for a simulation without cell wrapping.  yi-bing lin victor w. mak
simulation with insight  insight (ins) is a computer simulation language for describing systems in a quick, simple, and compact fashion. their description is executed by a computer and statistics summarizing the simulation are automatically provided. use of the language does not require any special programming or statistical expertise. complex models use the descriptive features of simple ones but incorporate more elaborate specifications. likewise sophisticated statistical and simulation procedures available in insight additions are additions rather than revisions of the model. simulations can be executed on mainframes when execution speed is needed or on a micro where interaction with the simulation and model development is facilitated. the net result is that the process of simulation modeling and the results from the simulations combine to provide "insight" into problem solving.  stephen d. roberts
animating wrinkles on clothes  this paper describes a method to simulate realistic wrinkles on clothes without fine mesh and large computational overheads. cloth has very little in- plane deformations, as most of the deformations come from buckling. this can be looked at as area conservation property of cloth. the area conservation formulation of the method modulates the user defined wrinkle pattern, based on deformation of individual triangle. the methodology facilitates use of small in-plane deformation stiffnesses and a coarse mesh for the numerical simulation, this makes cloth simulation fast and robust. moreover, the ability to design wrinkles (even on generalized deformable models) makes this method versatile for synthetic image generation. the method inspired from cloth wrinkling problem, being geometric in nature, can be extended to other wrinkling phenomena.  sunil hadap endre bangerter pascal volino nadia magnenat- thalmann
how to use expert advice  we analyze algorithms that predict a binary value by combining the predictions of several prediction strategies, called experts. our analysis is for worst- case situations, i.e., we make no assumptions about the way the sequence of bits to be predicted is generated. we measure the performance of the algorithm by the difference between the expected number of mistakes it makes on the bit sequence and the expected number of mistakes made by the best expert on this sequence, where the expectation is taken with respect to the randomization in the predictins. we show that the minimum achievable difference is on the order of the square root of the number of mistakes of the best expert, and we give efficient algorithms that achieve this. our upper and lower bounds have matching leading constants in most cases. we then show how this leads to certain kinds of pattern recognition/learning algorithms with performance bounds that improve on the best results currently know in this context. we also compare our analysis to the case in which log loss is used instead of the expected number of mistakes.  nicolò cesa-bianchi yoav freund david haussler david p. helmbold robert e. schapire manfred k. warmuth
geometric modelling and display primitives towards specialised hardware  work over the last ten years developing a simple geometric modelling scheme has led to the design of a high speed display processor capable of generating real time moving displays directly from a three dimensional model. the geometric model consists of a graph-matrix boundary representation linked to a boolean expression volume overlap representation. the architecture of the display processor is particularly suitable for implementation as a pipeline of vlsi components, and current work is exploring this possibility. a divide and conquer, quad tree algorithm applied to the boolean expression model allows the system to make use of scene coherence, and used with the hardware will make it possible to handle scenes of high complexity.  a. l. thomas
interactive multi-pass programmable shading  programmable shading is a common technique for production animation, but interactive programmable shading is not yet widely available. we support interactive programmable shading on virtually any 3d graphics hardware using a scene graph library on top of opengl. we treat the opengl architecture as a general simd computer, and translate the high-level shading description into opengl rendering passes. while our system uses opengl, the techniques described are applicable to any retained mode interface with appropriate extension mechanisms and hardware api with provisions for recirculating data through the graphics pipeline.  we present two demonstrations of the method. the first is a constrained shading language that runs on graphics hardware supporting opengl 1.2 with a subset of the arb imaging extensions. we remove the shading language constraints by minimally extending opengl. the key extensions are color range (supporting extended range and precision data types) and pixel texture (using framebuffer values as indices into texture maps). our second demonstration is a renderer supporting the renderman interface and renderman shading language on a software implementation of this extended opengl. for both languages, our compiler technology can take advantage of extensions and performance characteristics unique to any particular graphics hardware.  mark s. peercy marc olano john airey p. jeffrey ungar