waashk/acm huggingface dataset:
geo-spatial visualization for situational awareness (case study)  situational awareness applications require a highly detailed geospatial visualization covering a large geographic area. conventional polygon based terrain modeling would exceed the capacity of current computer rendering. terrain visualization techniques for a situational awareness application are described in this case study. visualizing large amounts of terrain data has been achieved using very large texture maps. sun shading is applied to the terrain texture map to enhance perception of relief features. perception of submarine positions has been enhanced using a translucent, textured water surface. each visualization technique is illustrated in the accompanying video tape.  eliot feibush nikhil gagvani daniel williams
fast and accurate hierarchical radiosity using global visibility  recent hierarchical global illumination algorithms permit the generation of images with a high degree of realism. nonetheless, appropriate refinement of light transfers, high quality meshing, and accurate visibility calculation can be challenging tasks. this is particularly true for scenes containing multiple light sources and scenes lit mainly by indirect light. we present solutions to these problems by extending a global visibility data structure, the visibility skeleton. this extension allows us to calculate exact point-to-polygon form- factors at vertices created by subdivision. the structures also provides visibility information for all light interactions, allowing intelligent refinement strategies. high-quality meshing is effected based on a perceptualy based ranking strategy which results in appropriate insertions of discontinuity curves into the meshes representing illumination. we introduce a hierarchy of triangulations that allows the generation of a hierarchical radiosity solution using accurate visibility and meshing. results of our implementation show that our new algorithm produces high quality view- independent lighting solutions for direct illumination, for scenes with multiple lights and also scenes lit mainly by indirect illumination.  fredo durand george drettakis claude puech
an interactive production planning simulation system (abstract only)  the manager of a large production facility is responsible for planning the needs of the factory based on estimates of production levels and production costs. a key towards successful planning is that of obtaining correct information about the factory and its operation. considered here is a modest database system which contains this information, and interactive means for updating this information, and a simulation program that uses only the database to operate (with appropriate user directives). this allows easy alteration of factory data and significantly reduces the complexity of the simulation. advantages of this approach are discussed.  alan w. carpenter corey d. schou
blitz: a rule-based system for massively parallel architectures  the rule-based system has emerged as an important tool to developers of artificial intelligence programs. because of the computational resources required to realize the match-select-execute cycle of rule-based systems, researchers have been trying to introduce parallelism into these systems for some time. we describe a new approach to parallel rule-based systems which exploits fine- grained hypercube hardware. the new algorithms for parallel rule matching and simultaneous execution of several rules at once are presented. experimental results using a connection machine* implementation of blitz are presented.  k. morgan
creating volume models from edge-vertex graphs  the design of complex geometric models has been and will continue to be one of the limiting factors in computer graphics. a careful enumeration of the properties of topologically correct models, so that they may be automatically enforced, can greatly speed this process. an example of the problems inherent in these methods is the "wire frame" problem, the automatic generation of a volume model from an edge-vertex graph. the solution to this problem has many useful applications in geometric modelling and scene recognition.  this paper shows that the "wire frame" problem is equivalent to finding the embedding of a graph on a closed orientable surface. such an embedding satisfies all the topological properties of physical volumes. unfortunately graphical embeddings are not necessarily unique. but when we restrict the embedding surface so that it is equivalent to a sphere, and require that the input graph be three-connected, the resulting object is unique. given these restrictions there exists a linear time algorithm to automatically convert the "wire frame" to the winged edge representation, a very powerful data structure. applications of this algorithm are discussed and several examples shown.  patrick m. hanrahan
fast texture synthesis using tree-structured vector quantization  texture synthesis is important for many applications in computer graphics, vision, and image processing. however, it remains difficult to design an algorithm that is both efficient and capable of generating high quality results. in this paper, we present an efficient algorithm for realistic texture synthesis. the algorithm is easy to use and requires only a sample texture as input. it generates textures with perceived quality equal to or better than those produced by previous techniques, but runs two orders of magnitude faster. this permits us to apply texture synthesis to problems where it has traditionally been considered impractical. in particular, we have applied it to constrained synthesis for image editing and temporal texture generation. our algorithm is derived from markov random field texture models and generates textures through a deterministic searching process. we accelerate this synthesis process using tree-structured vector quantization.  li-yi wei marc levoy
modelling database based expert systems at the conceptual level  in a conceptual modelling environment a model is given for analysing complex real world problems known as conceptual knowledge model (ckm), represented by a graphical representation and a formal representation. the graphical representation consist of 3 graphs: conceptual requirement graph, conceptual behavior graph, and conceptual structure graph. this graphs are developed by consulting the expert during the design process. the graphs are then transformed into first- order predicate logic to represent the non-logical axioms of a first order theory.  the model suggested here is a step towards closing the gap between data base theory and ai databases.  ramin yasdi
graphic input interaction techniques(panel session)  in the last decade most research and development in computer graphics has been in the output side. input devices and techniques for communicating with graphic systems are now also becoming active research topics. to communicate the state-of-the-art and to identify the key research issues, siggraph sponsored a workshop on graphics interaction input techniques in june, 1982. the topics to be discussed include tools for building user interfaces, recent successes using those tools, human factors, generic interaction types, interaction techniques for raster systems and style-independent interaction techniques. the workshop will be summarized with an address on the current state-of-the- art and identification of the major research issues. in addition, selected participants will be asked to address the primary research issues.  james j. thomas
automating gait generation  one of the most routine actions humans perform is walking. to date, however, an automated tool for generating human gait is not available. this paper addresses the gait generation problem through three modular components. we present elevwalker, a new low-level gait generator based on _sagittal elevation angles_, which allows curved locomotion - walking along a curved path - to be created easily; elevinterp, which uses a new _inverse motion interpolation_ algorithm to handle uneven terrain locomotion; and metagait, a high-level control module which allows an animator to control a figure's walking simply by specifying a path. the synthesis of these components is an easy-to-use, real-time, fully automated animation tool suitable for off-line animation, virtual environments and simulation.
an approach to 3d pose determination  the orientation, or pose, of an object is a fundamental property that helps to define the geometrical relationship between the object and its environment. in addition, knowledge of object orientation can also facilitate interpretive and decision-making tasks in a variety of practical domains, including industrial, meteorological, and medical applications. determining object pose, however, remains an open research question in the fields of graphics and visualization. this article describes a novel yet intuitively simple approach, which we call topological goniometry, to directly determine the pose of a three-dimensional object from 3d data. the topology of interest is that of two-sided surfaces in a three- manifold, and includes objects whose shaped are unaffected by elastic transformations. algorithmically, topological goniometry is composed of the following major steps. the first analyzes the global topology in order to generate a distribution of 3d coordinate triplets in the proximity of the desired pose axis. using this set of 3d points, that second step then invokes a "3d walk" algorithm that considers the local topology to produce a generalized curve representing an estimate of the object's axis of pose. the resultant pose axis is thus not constrained to lie along a straight line but can be generalized 3d curve. the methods are illustrated with a variety of synthetically created models that exhibit duct-like shapes, and are further tested by introducting noise as well as deformations to these models. the approach is also applied to a number of real discrete data obtained from meteorological and medical domains. the results suggest that the appproach is applicable to both real and synthetic datasets and is shown to be robust, computationally efficient, and applicable to a variety of problems. the approach can incorporate context- or application-dependent information about the object of interest by using a set of constraints that guide the process of orientation determination. this article describes the approach, its implementation, and the results obtained with numerous applications.  norberto ezquerra rakesh mullick
a similarity index for convex polygons (abstract only)  a new method for quantifying the shape similarity of two arbitrary convex polygons is presented. the intuitive notion of similarity is captured by computing the maximum area of intersection over every possible superposition of one polygon on the other. polygons are defined as regions bounded by conjunctive linear constraints of the form: a * x1 + a * x2 + a > = 0.0 (for i = 1,2,…, k). the problem is then reduced to one of non-differential optimization of three dimensions with an integral objective function. the maximum is taken over every possible rotation and translation of one polygon relative to the other. an extension of the method to arbitrary polygons is given where figures are partitioned into convex polygonal components. the results of classification experiments are presented as a comparison of this procedure with existing techniques.  guy bruno walter g. rudd
whole field modelling (case study): effective real-time and post-survey visualization of underwater pipelines  the detailed underwater bathymetric data provided by sonar research and development's high speed multi-frequency sonar transducer system provides new challenges in the development of interactive seabed visualization tools. this paper introduces a 'whole field modelling' system developed at sonar research and development ltd and the department of computer science, university of hull. this system provides the viewer with a new 3d underwater visualization environment that allows the user to pilot a virtual underwater vehicle around an accurate seabed model. in this paper we consider two example case studies that use the whole field modelling system for visualizing sonar data. both case studies, visualizing real-time pipeline dredging and pipe restoration visualization, are implemented using real survey data.  paul chapman derek wills peter stevens grahams brookes
optimal triangular haar bases for spherical data  multiresolution analysis based on fwt (fast wavelet transform) is now widely used in scientific visualization. spherical biorthogonal wavelets for spherical triangular grids where introduced in [5]. in order to improve on the orthogonality of the wavelets, the concept of nearly orthogonality, and two new piecewise-constant (haar) bases were introduced in [4]. in our paper, we extend the results of [4]. first we give two one-parameter families of triangular haar wavelet bases that are nearly orthogonal in the sense of [4]. then we introduce a measure of orthogonality. this measure vanishes for orthogonal bases. eventually, we show that we can find an optimal parameter of our wavelet families, for which the measure of orthogonality is minimized. several numerical and visual examples for a spherical topographic data set illustrates our results.  georges-pierre bonneau
the latent damage system: a jurisprudential analysis  this paper brings together the findings of two projects in the field of ai and law. the first of these was a jurisprudential inquiry into expert systems in law sometimes referred to as the oxford project. this work in fact originated in glasgow university in 1981, was developed in the course of doctoral legal research at oxford university from 1983 to 1986, and culminated in the publication of expert systems in law: a jurisprudential inquiry (oxford university press, 1987) by r e susskind. the second project was work on the latent damage system, the uk's first commercially available expert system in law. the development of that system has been fully documented in a case study by p n capper and r e susskind: latent damage law --- the expert system (butterworths , 1988), and a copy of the system itself is packaged with the book.  the purpose of this paper is to examine the latent damage project from the perspective of the oxford project --- the findings and methodology of a jurisprudential inquiry into expert systems in law are used to analyse the development and operation of one of the world's first operational systems.  the paper is structured in four parts. the first offers a brief overview of the oxford and latent damage projects. this is not undertaken in detail, as these projects have been documented extensively elsewhere. however, sufficient background information is given so that the paper can be read as a self- contained piece.  the central arguments and findings are presented in part two, which lays bare the jurisprudential foundations of the latent damage system. it does so in terms of the theories of jurisprudence that the oxford project established must underlie any expert system in law. part three examines the extent to which the development of the latent damage system was conditioned by the teachings of jurisprudence. finally, in part four, the users, function and scope of the latent damage system are pinpointed.  the purpose of this paper is not to demonstrate the power of the latent damage system by placing it within a jurisprudential framework. the power of the system is, in fact, best illustrated by running it and assessing its utility in practice. the overriding aim of the discussion here is to consider the relevance of the findings and recommendations of a highly academic project for those whose orientation is that of building real-life, commercial, practical systems.  r. e. susskind
frontier  in the full paper [1], we discuss the functionality and implementation challenges of the _frontier_ geometric constraint engine, designed to address the main reasons for the underutilization of geometric constraints in today's 3d design and assembly systems. here, we motivate the full paper by outlining the advantages of _frontier_.    * _frontie r_ fully enables both (a) the use of complex, cyclic, spatial constraint structures as well as (b) feature-based design. to deal with issue (a), _frontier_ relies on the efficient generation of a close-to-optimal _decomposition and recombination (dr) plan_ for completely general variational constraint systems (see figure 1). a serious bouleneck in constraint solving is the exponential time dependence on the size of the largest system that is simultaneously solved by the algebraic- numeric solver. in most naturally occurring cases, _frontier_'s dr-plan is guaranteed in minimize this size (to within a small constant factor). to deal with issue (b), _frontier_'s dr-plan admits the independent and local manipulation of features and sub-assemblies in one or more _underlying feature hierarchies that are input_ (figures 1 and 2). a dr-plan satisfying the above requirements is generated by the new _frontsier vertex algorithm (fa)_: the dr problem and its significance as well as fa and its performance with respect to several relevant and newly formalized abstract measures are described in [2, 3].    * _frontier_ employs a crucial representation of the dr-plan's subsystems or clusters, their hierarchy and their interaction this representation merges network flow information, as well as other geometric and combinatorial information in a natural manner. some of this information is obtained from an efficient flow- based algorithm for detecting small rigid sub-systems presented in [4]. the clarity of this representation is crucial in the concrete realization of fa's formal performance. more significantly, this representation allows _frontier_ to take advantage of its dr-plan in surprising and unsuspected ways listed below.  jianjun oung meera sitharam brandon moro adam arbree
the frame-definition language for customizing the raffaello structure-editor in host expert systems  the use of the language discussed here, is to customize an expert-system (es) construction tool, raffaello, in the application. we are concerned, here, with a version, being an es itself, of the frame-definition and navigation component of raffaello. allowed frame- topology may be deep, i. e. with an unbound depth of the tree. frame schemata of the application es are described by means of a production system (ps), "cupros", with particular conventions for conveying particular features: e. g. slotless repeatable subframes, or local cupros'es in instance's subtrees, n-to-n relation insertion, retrieval - key local definition, ancestry-driven disambiguation of polysemic slots, etc. examples are drawn from the application to onomaturge, an es for word- formation.  e nissan
polynomial texture maps  in this paper we present a new form of texture mapping that produces increased photorealism. coefficients of a biquadratic polynomial are stored per texel, and used to reconstruct the surface color under varying lighting conditions. like bump mapping, this allows the perception of surface deformations. however, our method is image based, and photographs of a surface under varying lighting conditions can be used to construct these maps. unlike bump maps, these polynomial texture maps (ptms) also capture variations due to surface self-shadowing and interreflections, which enhance realism. surface colors can be efficiently reconstructed from polynomial coefficients and light directions with minimal fixed-point hardware. we have also found ptms useful for producing a number of other effects such as anisotropic and fresnel shading models and variable depth of focus. lastly, we present several reflectance function transformations that act as contrast enhancement operators. we have found these particularly useful in the study of ancient archeological clay and stone writings.  tom malzbender dan gelb hans wolters
predicting the drape of woven cloth using interacting particles  we demonstrate a physically-based technique for predicting the drape of a wide variety of woven fabrics. the approach exploits a theoretical model that explicitly represents the microstructure of woven cloth with interacting particles, rather than utilizing a continuum approximation. by testing a cloth sample in a kawabata fabric testing device, we obtain data that is used to tune the model's energy functions, so that it reproduces the draping behavior of the original material. photographs, comparing the drape of actual cloth with visualizations of simulation results, show that we are able to reliably model the unique large-scale draping characteristics of distinctly different fabric types.  david e. breen donald h. house michael j. wozny
the space efficiency of a forest of quadtrees over a quadtree data structure (abstract only)  forest of quadtrees is a refinement of a quadtree data structure that is used to represent planar regions. forest of quadtrees provides space savings over regular quadtrees by concentrating vital information. this paper presents the construction of a quadtree for a planar region enclosed in a 2n × 2n image. this quadtree representation is then used to present the construction of a forest of quadtrees for the same region. examples of various regions represented as a quadtree and the space savings provided by a forest of quadtrees will then be given.  nancy gautier
a framework for the analysis of error in global illumination algorithms  in this paper we identify sources of error in global illumination algorithms and derive bounds for each distinct category. errors arise from three sources: inaccuracies in the boundary data, discretization, and computation. boundary data consists of surface geometry, reflectance functions, and emission functions, all of which may be perturbed by errors in measurement or simulation, or by simplifications made for computational efficiency. discretization error is introduced by replacing the continuous radiative transfer equation with a finite-dimensional linear system, usually by means of boundary elements and a corresponding projection method. finally, computational errors perturb the finite-dimensional linear system through imprecise form factors, inner products, visibility, etc., as well as by halting iterative solvers after a finite number of steps. using the error taxonomy introduced in the paper we examine existing global illumination algorithms and suggest new avenues of research.  james arvo kenneth torrance brian smits
efficient learning of continuous neural networks  we describe an efficient algorithm for learning from examples a class of feedforward neural networks with real inputs and outputs in a real-value generalization of the probably approximately correct (pac) model. these networks can approximate an arbitrary function with an arbitrary precision. the learning algorithm can accommodate a fairly general worst-case noise model. the main improvement over previous work is that the running time of the algorithm grows only polynomially as the size of the target network increases (there is still an exponential dependence on the dimension of the input space, however). the main computational tool is an iterative "loading" algorithm which adds new hidden units to the hypothesis network sequentially. this avoids the difficult problem of optimizing the weights of all units simultaneously.  pascal koiran
the design of the dipmeter advisor system  the dipmeter advisor system [11] attempts to emulate human expert performance in an important and specialized oil well-log interpretation task. the system is currently being used in a small number of schlumberger field log interpretation centers as an aid to human dipmeter interpreters.  in this paper, we describe the problem just enough to establish the vocabulary for discussing the program and the characteristics of the domain. we then present the internal structure of the program and attempt to put it in perspective with respect to first-generation expert systems. we discuss ways in which characteristics of the task domain impose constraints on the design or" signal interpretation programs, and attempt to extract knowledge useful to future expert system developers.  reid g. smith robert l. young