waashk/acm huggingface dataset:
graphics in overlapping bitmap layers  one of the common uses of bitmap terminals is storing multiple programming contexts in multiple, possibly overlapping, areas of the screen called windows. windows traditionally store the visible state of a programming environment, such as an editor or debugger, while the user works with some other program. this model of interaction is attractive for one-process systems, but to make full use of a multiprogramming environment, windows must be asynchronously updated, even when partially or wholly obscured by other windows. for example, a long compilation may run in one window, displaying messages as appropriate, while the user edits a file in another window.  this paper describes a set of low-level graphics primitives to manipulate overlapping asynchronous windows, called layers, on a bitmap display terminal. unlike previous window software, these primitives extend the domain of the general bitmap operator bitblt to include bitmaps that are partially or wholly obscured.  rob pike
incremental and hierarchical hilbert order edge equation polygon rasterizatione  _a rasterization algorithm must efficiently generate pixel fragments from geometric descriptions of primitives. in order to accomplish per-pixel shading, shading parameters must also be interpolated across the primitive in a perspective-correct manner. if some of these parameters are to be interpreted in later stages of the pipeline directly or indirectly as texture coordinates, then translating spatial and parametric coherence into temporal coherence will improve texture cache performance. finally, if framebuffer access is also organized around cached blocks, then organizing rasterization so fragments are generated in block-sequential order will maximize framebuffer cache performance. hilbert-order rasterization accomplishes these goals, and also permits efficient incremental evaluation of edge and interpolation equations._  michael d. mccool chris wales kevin moule
combatting rendering latency  latency or lag in an interactive graphics system is the delay between user input and displayed output. we have found latency and the apparent bobbing and swimming of objects that it produces to be a serious problem for head-mounted display (hmd) and augmented reality applications. at unc, we have been investigating a number of ways to reduce latency; we present two of these. slats is an experimental rendering system for our pixel-planes 5 graphics machine guaranteeing a constant single ntsc field of latency. this guaranteed response is especially important for predictive tracking. just-in-time pixels is an attempt to compensate for rendering latency by rendering the pixels in a scanned display based on their position in the scan.  marc olano jon cohen mark mine gary bishop
dynamic real-time deformations using space & time adaptive sampling  this paper presents a robust, adaptive method for animating dynamic visco- elastic deformable objects that provides a guaranteed frame rate. our approach uses a novel automatic _space and time adaptive_ level of detail technique, in combination with a large-displacement (green) strain tensor formulation. the body is partitioned in a non-nested multiresolution hierarchy of tetrahedral meshes. the local resolution is determined by a _quality condition_ that indicates where and when the resolution is too coarse. as the object moves and deforms, the sampling is refined to concentrate the computational load into the regions that deform the most. our model consists of a continuous differential equation that is solved using a local explicit finite element method. we demonstrate that our adaptive green strain tensor formulation suppresses unwanted artifacts in the dynamic behavior, compared to adaptive mass-spring and other adaptive approaches. in particular, damped elastic vibration modes are shown to be nearly unchanged for several levels of refinement. results are presented in the context of a virtual reality system. the user interacts in real-time with the dynamic object through the control of a rigid tool, attached to a haptic device driven with forces derived from the method.  gilles debunne mathieu desbrun marie-paule cani alan h. barr
a prolog system for case-based classification (abstract)  it is becoming apparent from the research of kolodner, schank, and others that case- based reasoning is an important tool for artificial intelligence. we have implemented a case-based system in prolog that classifies objects described by attribute-value pairs. it uses prolog's facilities to manage a case database and to encode features. the basis for classification is a "nearest neighbor" measure on a universal scale of similarity. the user specifies a scaling factor for naturally numeric data, thus allowing comparisons across dimensions. for non-numeric data, the user can specify numeric values on the standard scale for each value of the feature. for features that take on unordered values, the user can specify a standard difference to use in the case of inequality between values. cases can have missing values for any feature, a circumstance that arises often in real applications. in a comparison between cases where one has a missing value for a feature, a standard difference for that feature is used. the user can control the importance of features in classification by manipulating scale factors and the numbers assigned to non-numeric values. if the system misclassifies an object, it saves its description with the correct classification. as the user interacts with the program, new features can be introduced. the program has been tested successfully with numeric audiology data and with non-numeric descriptors. this program should make case-based classification more accessible to potential users.  william w. mcmillan christopher j. gardiner
real-time hatching  drawing surfaces using hatching strokes simultaneously conveys material, tone, and form. we present a real-time system for non-photorealistic rendering of hatching strokes over arbitrary surfaces. during an automatic preprocess, we construct a sequence of mipmapped hatch images corresponding to different tones, collectively called a _tonal art map_. strokes within the hatch images are scaled to attain appropriate stroke size and density at all resolutions, and are organized to maintain coherence across scales and tones. at runtime, hardware multitexturing blends the hatch images over the rendered faces to locally vary tone while maintaining both spatial and temporal coherence. to render strokes over arbitrary surfaces, we build a lapped texture parametrization where the overlapping patches align to a curvature-based direction field. we demonstrate hatching strokes over complex surfaces in a variety of styles.  emil praun hugues hoppe matthew webb adam finkelstein
an enriched knowledge model for formal ontological analysis this paper presents and motivates an extended ontology knowledgemodel which explicitly represents semantic information aboutconcepts. this knowledge model is grounded on the meta-propertiesof formal ontological analysis and it results from enriching theusual conceptual model with semantic information which preciselycharacterises the concept's properties and expected ambiguities,including which properties are prototypical of a concept and whichare exceptional, the behaviour of properties over time and thedegree of applicability of properties to subconceptsthis enrichedconceptual model permits a precise characterisation of what isrepresented by class membership mechanisms and helps a knowledgeengineer to determine, in a straightforward manner, themeta-properties holding for a concept. meta-properties arerecognised to be the main tool for a formal ontological analysisthat allows building ontologies with a clean and untangledtaxonomic structure. moreover, this enriched semantics facilitatesthe development of reasoning mechanisms on the state of affairsthat instantiates the ontologies. such reasoning mechanisms can beused in order to solve ambiguities that can arise when ontologiesare integrated and one needs to reason with the integratedknowledge. valentina a. m. tamma trevor bench-capon
semiring-based constraint satisfaction and optimization  we introduce a general framework for constraint satisfaction and optimization where classical csps, fuzzy csps, weighted csps, partial constraint satisfaction, and others can be easily cast. the framework is based on a semiring structure, where the set of the semiring specifies the values to be associated with each tuple of values of the variable domain, and the two semiring operations (+ and x) model constraint projection and combination respectively. local consistency algorithms, as usually used for classical csps, can be exploited in this general framework as well, provided that certain conditions on the semiring operations are satisfied. we then show how this framework can be used to model both old and new constraint solving and optimization schemes, thus allowing one to both formally justify many informally taken choices in existing schemes, and to prove that local consistency techniques can be used also in newly defined schemes.  stefano bistarelli ugo montanari francesca rossi
texture mapping progressive meshes  given an arbitrary mesh, we present a method to construct a progressive mesh (pm) such that all meshes in the pm sequence share a common texture parametrization. our method considers two important goals simultaneously. it minimizes texture stretch (small texture distances mapped onto large surface distances) to balance sampling rates over all locations and directions on the surface. it also minimizes texture deviation ("slippage" error based on parametric correspondence) to obtain accurate textured mesh approximations. the method begins by partitioning the mesh into charts using planarity and compactness heuristics. it creates a stretch-minimizing parametrization within each chart, and resizes the charts based on the resulting stretch. next, it simplifies the mesh while respecting the chart boundaries. the parametrization is re- optimized to reduce both stretch and deviation over the whole pm sequence. finally, the charts are packed into a texture atlas. we demonstrate using such atlases to sample color and normal maps over several models.  pedro v. sander john snyder steven j. gortler hugues hoppe
viable inference systems  because uncertain and provisional reasoning is an inherent part of intelligent systems, a diverse (and competing) array of formalisms for handling uncertain inference has been developed in theory and practice. each of these formalisms tends to be argued and justified on its own ground, starting from assumptions which ensure its "correctness" or "optimality." it is argued here, however, that the key concept for an intelligent system is viability \\- it is as unproductive to seek "correctness" in open inference systems as it would be to prove the "optimality" of a biological organism. several inference formalisms are examined in the light of this criticism. the viability of systems based on these formalisms is seen to rest critically on their robustness to changes in their context. the assumptions which usually function to hold that context fixed must thus be critically examined.  joseph deken
high-level design using helix  studies of architectures and performance trade-offs prior to implementation of an electronic design are critical to the success of the design. typically, software simulators are developed specifically for a single project and are discarded at the end of the project. the use of a general purpose behavioral simulation system can increase the productivity of such projects by 1) reducing the effort required to begin simulation, and 2) offering more capability than is typically available from a more specialized simulator. this paper discusses the use of a behavioral simulation system, helix, in the analysis of alternative network designs and protocols.  david r. coelho
interactive lens visualization techniques  this paper describes new techniques for minimally immersive visualization of 3d scalar and vector fields, and visualization of document corpora. in our glyph-based visualization system, the user interacts with the 3d volume of glyphs using a pair of button-enhanced 3d position and orientation trackers. the user may also examine the volume using an interactive lens, which is a rectangle that slices through the 3d volume and displays scalar information on its surface. a lens allows the display of scalar data in the 3d volume using a contour diagram, and a texture-based volume rendering.  christopher d. shaw james a. hall david s. ebert d. aaron roberts
computer rendering of stochastic models  a recurrent problem in generating realistic pictures by computers is to represent natural irregular objects and phenomena without undue time or space overhead. we develop a new and powerful solution to this computer graphics problem by modeling objects as sample paths of stochastic processes. of particular interest are those stochastic processes which previously have been found to be useful models of the natural phenomena to be represented. one such model applicable to the representation of terrains, known as "fractional brownian motion," has been developed by mandelbrot.  the value of a new approach to object modeling in computer graphics depends largely on the efficiency of the techniques used to implement the model. we introduce a new algorithm that computes a realistic, visually satisfactory approximation to fractional brownian motion in faster time than with exact calculations. a major advantage of this technique is that it allows us to compute the surface to arbitrary levels of details without increasing the database. thus objects with complex appearances can be displayed from a very small database. the character of the surface can be controlled by merely modifying a few parameters. a similar change allows complex motion to be created inexpensively.  alain fournier don fussell loren carpenter
explanation-based learning: a survey of programs and perspectives  explanation-based learning (ebl) is a technique by which an intelligent system can learn by observing examples. ebl systems are characterized by the ability to create justified generalizations from single training instances. they are also distinguished by their reliance on background knowledge of the domain under study. although ebl is usually viewed as a method for performing generalization, it can be viewed in other ways as well. in particular, ebl can be seen as a method that performs four different learning tasks: generalization, chunking, operationalization, and analogy.  this paper provides a general introduction to the field of explanation-based learning. considerable emphasis is placed on showing how ebl combines the four learning tasks mentioned above. the paper begins with a presentation of an intuitive example of the ebl technique. subsequently ebl is placed in its historical context and the relation between ebl and other areas of machine learning is described. the major part of this paper is a survey of selected ebl programs, which have been chosen to show how ebl manifests each of the four learning tasks. attempts to formalize the ebl technique are also briefly discussed. the paper concludes with a discussion of the limitations of ebl and the major open questions in the field.  thomas ellman
cmpack: a complete software system for autonomous legged soccer robots  this paper describes a completely implemented, fully autonomous software system for soccer playing quadruped ro\\\\-bots. the system includes real-time color vision, probabilistic localization, quadruped locomotion/motion, and a hierarchical behavior system. each component was based on well tested algorithms and approaches from other domains. our design exposed strengths and weaknesses in each component, and led to improvements and extensions that made them more capable in general, as well as better suited for our testing domain. integrating the components revealed design assumptions that were violated. we describe the problems that arose and how we addressed them.  the integrated system was then used at the annual robo\\\\-cup robotic soccer competition where we placed third, losing only a single game. we reflect on how our system addressed its goals and what was learned through implementation and testing on real robots.  scott lenser james bruce manuela veloso
a model for self-adaptation in a robot colony  a model for self- adaptation in a colony of robots to changes occurring in the environment is presented. the model employs two levels of computations : one at a metalevel and the other at a lowerlevel. the metalevel computations produce a learning behaviour in the robot which is responsible for the adaptation and those at the low-level control the robot motions. inductive learning is employed as the learning strategy. an instance of the 'producer- consumer' problem is presented in this context.  t v d kumar n parameswaran
visual simulation of smoke  in this paper, we propose a new approach to numerical smoke simulation for computer graphics applications. the method proposed here exploits physics unique to smoke in order to design a numerical method that is both fast and efficient on the relatively coarse grids traditionally used in computer graphics applications (as compared to the much finer grids used in the computational fluid dynamics literature). we use the inviscid euler equations in our model, since they are usually more appropriate for gas modeling and less computationally intensive than the viscous navier- stokes equations used by others. in addition, we introduce a physically consistent vorticity confinement term to model the small scale rolling features characteristic of smoke that are absent on most coarse grid simulations. our model also correctly handles the inter-action of smoke with moving objects.  ronald fedkiw jos stam henrik wann jensen
time-dependent visual adaptation for fast realistic image display  human vision takes time to adapt to large changes in scene intensity, and these transient adjustments have a profound effect on visual appearance. this paper offers a new operator to include these appearance changes in animations or interactive real-time simulations, and to match a user's visual responses to those the user would experience in a real-world scene.  large, abrupt changes in scene intensities can cause dramatic compression of visual responses, followed by a gradual recovery of normal vision. asymmetric mechanisms govern these time-dependent adjustments, and offer adaptation to increased light that is much more rapid than adjustment to darkness. we derive a new tone reproduction operator that simulates these mechanisms. the operator accepts a stream of scene intensity frames and creates a stream of color display images.  all operator components are derived from published quantitative measurements from physiology, psychophysics, color science, and photography. ept intentionally simple to allow fast computation, the operator is meant for use with real-time walk-through renderings, high dynamic range video cameras, and other interactive applications. we demonstrate its performance on both synthetically generated and acquired "real-world" scenes with large dynamic variations of illumination and contrast.  sumanta n. pattanaik jack tumblin hector yee donald p. greenberg
digital halftones by dot diffusion  this paper describes a technique for approximating real-valued pixels by two- valued pixels. the new method, called dot diffusion, appears to avoid some deficiencies of other commonly used techniques. it requires approximately the same total number of arithmetic operations as the floyd-steinberg method of adaptive grayscale, and it is well suited to parallel computation; but it requires more buffers and more complex program logic than other methods when implemented sequentially. a "smooth" variant of the method may prove to be useful in high-resolution printing.  donald e. knuth
integrating tools and infrastructures for generic multi-agent systems  in this paper, we present madkit/sedit, an agent infrastructure combined with a generic design tool for multi-agent systems. this toolkit is based on a organizational metaphor to integrate highly heterogeneous agent systems.  we explain the principles of madkit, the underlying agent platform, and show how it can integrate various agent architectures and provides structuration for multiple simultaneous systems and semantics. the architecture, based on a minimal agent runtime, agentified platform services and modular application host, is presented. the sedit design tool, built itself as a mas is also discussed. we present its key points in terms of multi-model support, and integration with the infrastructure, from design to maintenance.  we illustrate our approach by discussing some consequences of this architecture, and describe our motivation for this design: integration and reuse, organizational patterns, and overall versatility. a summary is given of some key madkit-based applications to date.  olivier gutknecht jacques ferber fabien michel
texture synthesis on surfaces  many natural and man-made surface patterns are created by interactions between texture elements and surface geometry. we believe that the best way to create such patterns is to synthesize a texture directly on the surface of the model. given a texture sample in the form of an image, we create a similar texture over an irregular mesh hierarchy that has been placed on a given surface.  our method draws upon texture synthesis methods that use image pyramids, and we use a mesh hierarchy to serve in place of such pyramids. first, we create a hierarchy of points from low to high density over a given surface, and we connect these points to form a hierarchy of meshes. next, the user specifies a vector field over the surface that indicates the orientation of the texture. the mesh vertices on the surface are then sorted in such a way that visiting the points in order will follow the vector field and will sweep across the surface from one end to the other. each point is then visited in turn to determine its color. the color of a particular point is found by examining the color of neighboring points and finding the best match to a similar pixel neighborhood in the given texture sample. the color assignment is done in a coarse-to-fine manner using the mesh hierarchy. a texture created this way fits the surface naturally and seamlessly.  greg turk
a continuous process simulation using gpss  this paper describes the methodology and results of a simulation of an oil purification process used by a food processing company in toronto, ontario. the process involves reacting a mixture of edible oils with a caustic solution to precipitate out various free fatty acid and gum components in the oils in the form of soap solids.  the process is discrete in that batches of crude oil are processed individually but the processing of each batch is done on a continuous basis.  the simulation model developed for this process simulates one crude oil batch at a time. thus the model simulates an essentially continuous operation. the success of gpss, a discrete event simulation language, in simulating this continuous process forms the basis of this paper.  robert greer lavery