waashk/acm huggingface dataset:
impulse-based simulation of rigid bodies  we introduce a promising new approach to rigid body dynamic simulation called impulse- based simulation. the method is well suited to modeling physical systems with large numbers of collisions, or with contact modes that change frequently. all types of contact (colliding, rolling, sliding, and resting) are modeled through a series of collision impulses between the objects in contact, hence the method is simpler and faster than constraint- based simulation. we have implemented an impulse-based simulator that can currently achieve interactive simulation times, and real time simulation seems within reach. in addition, the simulator has produced physically accurate results in several qualitative and quantitative experiments. after giving an overview of impulse-based dynamic simulation, we discuss collision detection and collision response in this context, and present results from several experiments.  brian mirtich john canny
multiresolution curves  we describe a multiresolution curve representation, based on wavelets, that conveniently supports a variety of operations: smoothing a curve; editing the overall form of a curve while preserving its details; and approximating a curve within any given error tolerance for scan conversion. we present methods to support continuous levels of smoothing as well as direct manipulation of an arbitrary portion of the curve; the control points, as well as the discrete nature of the underlying hierarchical representation, can be hidden from the user. the multiresolution representation requires no extra storage beyond that of the original control points, and the algorithms using the representation are both simple and fast.  adam finkelstein david h. salesin
rotated dispersed dither: a new technique for digital halftoning  rotated dispersed-dot dither is proposed as a new dither technique for digital halftoning. it is based on the discrete one-to-one rotation of a bayer dispersed-dot dither array. discrete rotation has the effect of rotating and splitting a significant part of the frequency impulses present in bayer's halftone arrays into many low-amplitude distributed impulses. the halftone patterns produced by the rotated dither method therefore incorporate fewer disturbing artifacts than the horizontal and vertical components present in most of bayer's halftone patterns. in grayscale wedges produced by rotated dither, texture changes at consecutive gray levels are much smoother than in error diffusion or in bayer's dispersed-dot dither methods, thereby avoiding contouring effects.  due to its semi-clustering behavior at mid-tones, rotated dispersed-dot dither exhibits an improved tone reproduction behavior on printers having a significant dot gain, while maintaining the high detail rendition capabilities of dispersed-dot halftoning algorithms. besides their use in black and white printing, rotated dither halftoning techniques have also been successfully applied to in-phase color reproduction on ink-jet printers.  victor ostromoukhov roger d. hersch isaac amidror
knowledge representation and inference control of speril-ii  speril-ii is an expert system for damage assessment of existing structures. fuzzy sets for imprecise data and dempster and shafer's theory for combining fuzzy sets with certainty factors are used in an inexact inference. since the process of the damage assessment is quite complex, metarules are used to control the inference in order to improve the effectiveness and reliability of results. the metarules in speril-ii are represented in logic form with emphases on the explicit representation of the selection of the rule group and the suitable inference method.  h. ogawa k. s. fu j. t. p. yao
visualizing quaternion rotation  quaternions play a vital role in the representation of rotations in computer graphics, primarily for animation and user interfaces. unfortunately, quaternion rotation is often left as an advanced topic in computer graphics education due to difficulties in portraying the four-dimensional space of the quaternions. one tool for overcoming these obstacles is the quaternion demonstrator, a physical visual aid consisting primarily of a belt. every quaternion used to specify a rotation can be represented by fixing one end of the belt and rotating the other. multiplication of quaternions is demonstrated by the composition of rotations, and the resulting twists in the belt depict visually how quaternions interpolate rotation.  this article introduces to computer graphics the exponential notation that mathematicians have used to represent unit quaternions. exponential notation combines the angle and axis of the rotation into concise quaternion expression. this notation allows the article to present more clearly a mechanical quaternion demonstrator consisting of a ribbon and a tag, and develop a computer simulation suitable for interactive educational packages. local deformations and the belt trick are used to minimize the ribbon's twisting and simulate a natural-appearing interactive quaternion demonstrator.  john c. hart george k. francis louis h. kauffman
precision requirements for digital color reproduction  an environment was established to perform device-independent color reproduction of full-color pictorial images. in order to determine the required precision for this environment, an experiment was performed to psychophysically measure colorimetric tolerances for six images using paired comparison techniques. these images were manipulated using 10 linear and nonlinear functions in the cielab dimensions of lightness, chroma, and hue angle. perceptibility tolerances were determined using probit analysis. from these results, the necessary precision in number of bits per color channel was determined for both the cielab and the crt rgb device color spaces. for both the cielab color space and the crt rgb device space, approximately eight color bits per channel were required for imperceptible color differences for pictorial images, and 10 bits per channel were required for computational precision.  mike stokes mark d. fairchild roy s. berns
identification of implicit legal requirements with legal abstract knowledge  in order to acquire legal rules from legal texts, legal requirements and legal effects must be identified. however, some of legal requirements are expressed implicitly. such implicit legal requirements can be found by lawyers when they understand legal texts. in this paper, to mechanize legal knowledge acquisition process, a lawyer's understanding process of legal texts is analyzed. the lawyer's understanding process can be viewed as an abductive reasoning process, since the lawyer can introduce implicit legal requirements which have not appeared in legal texts. this paper models such a reasoning process when lawyers understand legal texts. based on the analysis of lawyer's understanding process, a knowledge acquisition support system is proposed.  seiichiro sakurai hajime yoshino
nova*gks, a distributed implementation of the graphical kernel system  nova*gks is an implementation of the draft international standard graphical kernel system (gks), built using a distributed architecture. the specifications for gks present an implementor with many design tradeoff decisions. the implementors of nova*gks have analyzed those tradeoffs and created a distributed design which allows users of the package to design applications which can perform efficiently on many different graphics hardware configurations.  clinton n. waggoner charles tucker christopher j. nelson
exploring the forms of model diagnosis in a simulation support environment  our purpose is to explain the categorization of diagnostic assistance, using an example, in order to address the central question for a simulation support environment:  in what forms can computer assistance be provided to improve the simulation model development task?  this question must be answered in the context of the economic and technical realities of today, for the near future, and the long term. we present several examples of computer assistance which indicate that a significant degree of assistance is possible.  richard e. nance c. michael overstreet
simplified representation of vector fields  vector field visualization remains a difficult task. although many local and global visualization methods for vector fields such as flow data exist, they usually require extensive user experience on setting the visualization parameters in order to produce images communicating the desired insight. we present a visualization method that produces simplified but suggestive images of the vector field automatically, based on a hierarchical clustering of the input data. the resulting clusters are then visualized with straight or curved arrow icons. the presented method has a few parameters with which users can produce various simplified vector field visualizations that communicate different insights on the vector data.  alexandru telea jarke j. van wijk
adding immersion to collaborative tools  while three dimensional collaborative environments have been used for industrial design or interactive games, workgroup collaboration has largely remained in the two-dimensional realm. in this paper, we examine the collaborative capabilities of the collaborative virtual workspace, and how it is used. we then describe our effort to augment this system with an immersive display. by developing an immersive interface to an existing collaboration tool rather than adding collaboration to an immersive world, we hope to discover the advantages and pitfalls that immersive collaboration environments might offer. the first step in this process is to design the immersive environment to provide natural interactions for the activities users normally perform while working within the collaborative environment.  edward swing
scribe support in gnu emacs  think of scribe1 as a compiler for a document description language; scribe is not an editor. scribe is a "high level" document processing system, or a "composition engine" which permits users to deal with documentation at a higher level of abstraction than is possible with "word-processors" or "page processors." one of the methods used to provide this higher level of abstraction is the separation2 of the "form" or "layout" of the document from the "content;" thus avoiding distraction of the document's author with superfluous details of document format. this frees the writer to concentrate on the content of a document, rather than its format.  with the increasing popularity of wysiwyg3 style editors, which are more properly described as "page processing" systems; fewer people are willing to insert the type of "mark-up" commands required to properly use a "document processing" system such as scribe. described herein are a set of support functions, written in a dialect of lisp, which provide assistance to the scribe user during the preparation and composition of documents. these support functions provide "short-cuts" for insertion of scribe mark-up, as well as certain features useful during composition and maintenance of large documents. collectively, these support functions are called "scribe mode" and are written to be used with the "gnu emacs" editor.4 gnu emacs is known to run under the unix5 and vax/vms6 operating systems, and various versions have been observed to operate on a wide variety of host computers, and other operating systems.  j. e. black
forward image mapping  we present a new forward image mapping algorithm, which speeds up perspective warping --- as in texture mapping. it processes the source image in a special scanline order instead of the normal raster scanline order. this special scanline has the property of preserving parallelism when projecting to the target image. the algorithm reduces the complexity of perspective-correct image warping by eliminating the division per pixel and replacing it with a division per scanline. the method also corrects the perspective distortion in gouraud shading with negligible overhead. furthermore, the special scanline order is suitable for antialiasing using a more accurate antialiasing conic filter, with minimum additional cost. the algorithm is highlighted by incremental calculations and optimized memory bandwidth by reading each source pixel only once, suggesting a potential hardware implementation.  baoquan chen frank dachille arie kaufman
the role of simulation in planning  theoretical work in automated planning research has shown that the popular methods used for doing automated planning either cannot be extended into real world domains, or are computationally intractable. this paper discusses the paradigm of simulation- based planning which attempts to overcome these difficulties. simulation-based planning uses some simulation techniques to gather information for guiding the planner. the resulting system can handle more complex domains with much improved performance over previous systems, while making only a small compromise in completeness. implemented systems are described.  daved p. miller
real-time visualization of scalably large collections of heterogeneous objects (case study)  this paper presents results for real-time visualization of out-of-core collections of 3d objects. this is a significant extension of previous methods and shows the generality of hierarchical paging procedures applied both to global terrain and any objects that reside on it. applied to buildings, the procedure shows the effectiveness of using a screen-based paging and display criterion within a hierarchical framework. the results demonstrate that the method is scalable since it is able to handle multiple collections of buildings (e.g., cities) placed around the earth with full interactivity and without extensive memory load. further the method shows efficient handling of culling and is applicable to larger, extended collections of buildings. finally, the method shows that levels of detail can be incorporated to provide improved detail management.  douglas davis william ribarsky t. y. jiang nickolas faust sean ho
evidential logic and dempster-shafer theory  most artificial intelligence applications require reasoning with uncertainty and incompleteness. such information is not captured in terms of simple true and false values nor in terms of probabilistic estimates when relevant statistical data are lacking. in this paper, we extend nilsson's probabilistic logic, a semantic generalization of logic, in which the truth value of a sentence is a probability value between Ø and 1 to evidential logic in the framework of dempster-shafer theory.  s s chen
a multi-agent planning system (abstract only)  this report describes a planning system that generates a sequence of operations (actions) assignments for each agent to achieve a goal statement in a multi-agent problem domain. the system is characterized by a pre-analysis of the goal statement and a representation of the breakable and unbreakable operations. the analysis would yield a sequence of parallel groups of subgoals and the execution sequence of subgoals within a group. (two groups of subgoals are parallel to each other, if they can be achieved separately by different agents). following this analysis result, a plan generator dynamically assigns a group of subgoals to each agent and formulates the detailed plans. in order to increase the utility of agents, the plan generator always tries to assign an idle agent to assist a busy agent if a group of subgoals is not available at that particular instance. this is done by identifying the breakable and the unbreakable subtasks of an agent and assigning one part of the breakable subtask or a sequence of unbreakable subtasks to an idle agent.  two major system components are being investigated: the goal statement analysis and the operation representations.  the purpose of the goal statement analysis is to use the domain specific knowledge to examine the relationships among the subgoals, to group the correlated subgoals, to find the parallelism among the groups, and to determine the execution sequences of subgoals within a group and the pursuing orders of the groups. the system described here avoids the fruitless search efforts by 1. grouping the correlated subgoals together and assigning each group to an agent so that the complexity of a problem is reduced, 2. ordering the subgoal sequence within a group so that the trial-and-error search can be eliminated.  the study of the operation representations has focused on the representations of the breakable and the unbreakable operation sequences. a sequence of operations is called breakable if each component in the sequence can be carried out by different agents. in contrast to the breakable sequence, an unbreakable sequence consists of operations that must be carried out by the same agent. the purpose of this distinction is to specify what portion of a task can be assisted by an idle agent and what portion has to be completed by the same agent if this agent has started it.  kai-hsiung chang
ray tracing with cones  a new approach to ray tracing is introduced. the definition of a "ray" is extended into a cone by including information on the spread angle and the virtual origin. the advantages of this approach, which tries to model light propagation with more fidelity, include a better method of anti-aliasing, a way of calculating fuzzy shadows and dull reflections, a method of calculating the correct level of detail in a procedural model and texture map, and finally, a procedure for faster intersection calculation.  john amanatides
entropy and self-organization in multi-agent systems  emergent self- organization in multi-agent systems appears to contradict the second law of thermodynamics. this paradox has been explained in terms of a coupling between the macro level that hosts self-organization (and an apparent reduction in entropy), and the micro level (where random processes greatly increase entropy). metaphorically, the micro level serves as an entropy "sink", permitting overall system entropy to increase while sequestering this increase from the interactions where selforganization is desired. we make this metaphor precise by constructing a simple example of pheromone-based coordination, defining a way to measure the shannon entropy at the macro (agent) and micro (pheromone) levels, and exhibiting an entropybased view of the coordination.  h. van dyke parunak sven brueckner
sketching in 3d of the numerous changes to the implements for creating 2d images and 3d models, one of the most radical has been the recent adoption of wimp interfaces. ironically, there is good reason to believe that wimp interaction for 3d modeling is actually inferior to the real-world interfaces (pencils, large sheets of paper, clay, paint palettes) that it supplants. in fact, wimp interaction's principal benefit is its straightforward integration with computer 3d model representations which have many advantages including ease of transformation, archival, replication and distribution.instead of interpreting user compliance as an affirmation of wimp interaction, we explore the dichotomy of how easy it is to depict a 3d object with just a pencil and paper, and how hard it is to model the same object using a multithousand dollar workstation. our challenge is to blend the essence of pencil sketching interfaces with the power of computer model representations.this paper presents an overview of ongoing research in "sketch-like" 3d modeling user interfaces. the objective of this research is to design interfaces that match human ergonomics, exploit prelearned skills, foster new skills and support the transition from novice to skilled expert. thus pencil sketching is an interaction ideal, supporting users ranging from children to adults, and from doodlers to artists. perhaps the best testament to the effectiveness of the pencil and paper interface is that very few people even consider it a user interface. robert zeleznik
efficient octree conversion by connectivity labeling  we present an algorithm for converting from the boundary representation of a solid to the corresponding octree model. the algorithm utilizes an efficient new connected components labeling technique. a novelty of the method is the demonstration that all processing can be performed directly on linear quad and octree encodings. we illustrate the use of the algorithm by an application to geometric mine modeling and verify its performance by analysis and practical experiments.  markku tamminen hanan samet
introduction to gpss  summary information about key aspects of the simulation programming language gpss is provided. the class of problems to which gpss applies especially well is described; commentary on the semantics and syntax of the language is offered; the learning-oriented literature for gpss is summarized; various gpss implementations are commented on; the time- sharing networks offering gpss are cited; and public courses on the language are listed. finally, the source of a tutorial introduction to the fundamental semantics and syntax of gpss is given. copies of this tutorial material, excluded from reproduction here because of page-count limits, will be distributed at the session and provide the basis for the session itself.  thomas j. schriber
merging and transformation of raster images for cartoon animation  the task of assembling drawings and backgrounds together for each frame of an animated sequence has always been a tedious undertaking using conventional animation camera stands and has contributed to the high cost of animation production. in addition, the physical limitations that these camera stands place on the manipulation of the individual artwork levels restricts the total image-making possibilities afforded by traditional cartoon animation. documents containing all frame assembly information must also be maintained.  this paper presents several computer methods for assisting in the production of cartoon animation, both to reduce expense and to improve the overall quality.  merging is the process of combining levels of artwork into a final composite frame using digital computer graphics. the term "level" refers to a single painted drawing (cel) or background. a method for the simulation of any hypothetical animation camera set-up is introduced. a technique is presented for reducing the total number of merges by retaining merged groups consisting of individual levels which do not change over successive frames. lastly, a sequence-editing system which controls precise definition of an animated sequence, is described. also discussed is the actual method for merging any two adjacent levels and several computational and storage optimizations to speed the process.  bruce a. wallace
the circle-brush algorithm  brushing commonly refers to the drawing of curves with various line widths in hit- mapped graphics systems. it is best done with circles of suitable diameter so that a constant line width, independent of the curve's slope, is obtained. allowing all possible integer diameters corresponding to all possible integer line widths results in every second width having an odd value. thus, the underlying circle algorithm must be able to handle both integer and half- integer radii. our circle-brush algorithm handles both situations and produces a "best approximation": all grid points produced simultaneously minimize (1) the residual, (2) the euclidean distance to the circle, and (3) the displacement along the grid line from the intersection with the circle. our circle-brush algorithm was developed in careful consideration of its implementation in vlsi.  k. c. posch w. d. fellner