waashk/acm huggingface dataset:
feature sensitive surface extraction from volume data  the representation of geometric objects based on volumetric data structures has advantages in many geometry processing applications that require, e.g., fast surface interrogation or boolean operations such as intersection and union. however, surface based algorithms like shape optimization (fairing) or freeform modeling often need a topological manifold representation where neighborhood information _within_ the surface is explicitly available. consequently, it is necessary to find effective conversion algorithms to generate explicit surface descriptions for the geometry which is implicitly defined by a volumetric data set. since volume data is usually sampled on a regular grid with a given step width, we often observe severe alias artifacts at sharp features on the extracted surfaces. in this paper we present a new technique for surface extraction that performs feature sensitive sampling and thus reduces these alias effects while keeping the simple algorithmic structure of the standard marching cubes algorithm. we demonstrate the effectiveness of the new technique with a number of application examples ranging from csg modeling and simulation to surface reconstruction and remeshing of polygonal models.  leif p. kobbelt mario botsch ulrich schwanecke hans-peter seidel
validation of simulation models: the weak/missing link  the validation of the simulation model is generally acknowledged as an integral part of a simulation project. there is, however, no general agreement on how simulation models should be verified and there is often confusion as to the difference between validation and verification. in this paper we first set forth a framework for verification and validation as well as some of the more commonly suggested methods to be used. we then turn to the literature on the application of simulation to see how models are, in practice, verified and validated. to our surprise we found that in the vast majority of the reported applications of simulation there is no mention of verification or validation of the simulation model, and when it is included, typically a single sentence or two is all that is devoted to how the model's credibility was established. we classified reported applications by type of author, organization type and source and found no significant difference in the frequency of the inclusion of verification or validation as part of the reported application.  stewart v. hoover ronald f. perry
cooperative multi-agent intelligent field terminals  we have developed a method for improving cooperation in complex systems that uses multi- agent (ma) intelligent field terminals (ifts). the ma function evaluates the control conditions of the overall system and the conditions of the other ifts. to shorten the turn- around time for data transfer among ifts, the conflicts that occur when the data processed by different ifts is inconsistent or irregular must be resolved autonomously. we thus incorporate a predictive agent in each ift, and these agents cooperate to resolve the conflicts. experimental results showed that this method not only provides adequate controls but also reduces the load on the network and the turn- around time when the number of ifts is less than 30.  juichi kosakaya katsunori yamaoka
irs: a hierarchical knowledge based system for aerial image interpretation  a knowledge based architecture for the interpretation of aerial images is presented. the image recognition system (irs) utilises a multiresolution perceptual clustering methodology as a robust alternative to the more traditional edge or region based approaches. initially, data driven feature generation and primary perceptual clustering is performed independently for two or more reduced resolution versions of the image. a rule based frame system (rbfs) is then used to instantiate more complex geometrical structures from symbolic multiresolution feature representations. final interpretation is achieved by using knowledge of contextual relations between objects in the domain.  steve cosby ray thomas
a task-based architecture for application-aware adjuncts  users of complex applications need advice, assistance, and feedback while they work. we are experimenting with "adjunct" user agents that are aware of the history of interaction surrounding the accomplishment of a task. this paper describes an architectural framework for constructing these agents. using this framework, we have implemented a critiquing system that can give task-oriented critiques to trainees while they use operating system tools and software applications. our approach is generic, widely applicable, and works directly with off-the-shelf software packages.  robert farrell peter fairweather eric breimer
the simulation of natural phenomena (panel session)  this panel will discuss the issues and the problems associated with the simulation of natural phenomena. this is a difficult area of research since it generally involves complex data bases and in many instances time variant phenomena. the computational loads can become enormous as one considers the physics or the mathematical modeling of structures.  most items in nature, trees, clouds, fire and comets being some examples, have not been displayed realistically in computer graphics. this lack stems from a few different problems, all of which are significant. the first is the fact that realistic portrayals require large amounts of storage and consequently large compute time. nature is able to create diverse detail at the most minute levels within an object of grandoise scale. the second problem is that of diversity of design within a given framework. for example, if a scene requires two dozen poplar trees, how does the designer construct trees that look different but are undeniably poplars? humans typically become tired after the first few iterations of such a design process, with a resulting degradation in the subsequent models. clearly, this problem applies to all of the phenomena mentioned above. finally, there is a lack of models. first, second and third order representations are commonly used in computer graphics to model various kinds of surfaces and their boolean combinations. however, their applications to objects, which do not lend themselves well to being described as surfaces has not been addressed sufficiently.  previous attempts at realism have dealt with the appearances of the surfaces being modeled, in terms of their illumination or relief. more recently, fractal methods have introduced a new degree of realism into terrain modeling systems. however, it appears that natural phenomena will require more research into the fundamental way things occur in nature, and in terms of computer graphics, their representation will build on previous work, but will still require new modeling techniques.  charles a. csuri james blinn julian gomez nelson max william reeves
modelling reasoning about evidence in legal procedure  this article investigates the modelling of reasoning about evidence in legal procedure. to this end, a dialogue game model of the relevant parts of dutch civil procedure is developed with three players: two adversaries and a judge. the model aims to be both legally realistic and technically well-founded. legally, the main achievement is a more realistic account of the judge's role in legal procedures than that provided by current models. technically, the model aims to preserve the features of an earlier-developed framework for two- player argumentative dialogue systems.  henry prakken
explanation systems for computer simulations  explanation systems supply information that clarifies the structure and problem domain of a computer program for the user. we begin our paper by describing the early explanation systems, which were built for expert system programs, and by reviewing some of the subsequent developments in artificial intelligence that relate to this area. the results of our research are consistent with some of the recent developments in artificial intelligence; we have found that there are a variety of kinds of information that are useful to naive users of computer programs. we have been particularly interested in writing programs that can supply such information to naive users of numerical computer simulations. we describe an implemented explanation system, naturalist, which explains the structure and domain of a simulation for inventory control. our experience with the naturalist program suggests that explanation facilities may be valuable additions to numerical computer simulations.  david h. helman akash bahuguna
image-driven simplification  we introduce the notion of image-driven simplification, a framework that uses images to decide which portions of a model to simplify. this is a departure from approaches that make polygonal simplification decisions based on geometry. as with many methods, we use the edge collapse operator to make incremental changes to a model. unique to our approach, however, is the use at comparisons between images of the original model against those of a simplified model to determine the cost of an ease collapse. we use common graphics rendering hardware to accelerate the creation of the required images. as expected, this method produces models that are close to the original model according to image differences. perhaps more surprising, however, is that the method yields models that have high geometric fidelity as well. our approach also solves the quandary of how to weight the geometric distance versus appearance properties such as normals, color, and texture. all of these trade- offs are balanced by the image metric. benefits of this approach include high fidelity silhouettes, extreme simplification of hidden portions of a model, attention to shading interpolation effects, and simplification that is sensitive to the content of a texture. in order to better preserve the appearance of textured models, we introduce a novel technique for assigning texture coordinates to the new vertices of the mesh. this method is based on a geometric heuristic that can be integrated with any edge collapse algorithm to produce high quality textured surfaces.  peter lindstrom greg turk
types of monotonic language learning and their characterization  the present paper deals with strong-monotonic, monotonic and weak-monotonic language learning from positive data as well as from positive and negative examples. the three notions of monotonicity reflect different formalizations of the requirement that the learner has to produce always better and better generalizations when fed more and more data on the concept to be learnt. we characterize strong-monotonic, monotonic, weak-monotonic and finite language learning from positive data in terms of recursively generable finite sets, thereby solving a problem of angluin (1980). moreover, we study monotonic inference with iteratively working learning devices which are of special interest in applications. in particular, it is proved that strong-monotonic inference can be performed with iteratively learning devices without limiting the inference capabilities, while monotonic and weak-monotonic inference cannot.  steffen lange thomas zeugmann
a lens and aperture camera model for synthetic image generation  this paper extends the traditional pin-hole camera projection geometry, used in computer graphics, to a more realistic camera model which approximates the effects of a lens and an aperture function of an actual camera. this model allows the generation of synthetic images which have a depth of field, can be focused on an arbitrary plane, and also permits selective modeling of certain optical characteristics of a lens. the model can be expanded to include motion blur and special effect filters. these capabilities provide additional tools for highlighting important areas of a scene and for portraying certain physical characteristics of an object in an image.  michael potmesil indranil chakravarty
a shading approach to non-convex clipping  the conventional way of clipping a graphic object with a rectangular window or any convex polygon is to cut the object along a line tangent to each side of the polygon. parts of the object on the exterior side of the line are thrown away. after repeating the process for all of the sides, what remains is the clipped object.  however, this process fails if the clipping window is non-convex, i.e., has one or more corners that point inward, or if the window consists of more than one polygon. too much then gets clipped away. one way of dealing with this situation is to break up the window into simple convex polygons. the object is clipped with each polygon in turn, and the results are joined together to form the final result.  a different approach, presented here, is to use shading logic. the window is seen as an area to be shaded, and the object, as the shading pattern. that is, the window is shaded with the object. the method yields not only the clipped object, but also, as a by-product, the reverse clipping, i.e., that part of the object that lies outside the window. this is an advantage in graphics editing where both clippings are often needed in parallel.  thomas l. springall gustav tollet
the bisector surface of rational space curves  given a point and a rational curve in the plane, their bisector curve is rational [farouki and johnston 1994a]. however, in general, the bisector of two rational curves in the plane is not rational [farouki and johnstone 1994b]. given a point and a rational space curve, this art icle shows that the bisector surface is a rational ruled surface. moreover, given two rational space curves, we show that the bisector surface is rational (except for the degenerate case in which the two curves are coplanar).  gershon elber myung-so kim
employing voice back channels of facilitate audio document retrieval  human listeners use voice back channels to indicate their comprehension of a talker's remarks. this paper describes an attempt to build a user interface capable of employing these back channel responses for flow control purposes while presenting a variety of audio information to a listener. acoustic evidence based on duration and prosody (rhythm and melody) of listeners' utterances is employed as a means of discriminating responses by discourse function without using word recognition. such an interface has been applied to three tasks: speech synthesis of driving directions, speech synthesis of electronic mail, and retrieval of recorded voice messages.  chris schmandt
on the power of qualitative simualation for estimating diffusion transit times  models describing the process of qualitative reasoning have significantly enhanced our insight into the general nature of the challenges involved in modeling people's imaginations when they think about complex processes. the composite picture created by combining models suggested by individual researchers may appear blurred this is because, in some cases, the range of applicability of each approach is not sharply defined, and the theoretical claims supporting the work are not sufficiently stated. this state of the art clearly suggests that considerable amount of research is still required in order to reinforce the theoretical foundations for the modeling qualitative reasoning. in this paper i first describe some of the approaches used for qualitative simulation. second, i discuss present the example of diffusion process in complicated media and the challenges involved in automating the qualitative estimations of diffusion transit times.  s. l. hardt
procedure models for generating three-dimensional terrain  a method for generating arbitrary terrain models, including trees, bushes, mountains, and buildings, is described. procedure models are used to combine fundamental data elements in the creation of unified objects comprising the terrain model. as an example, a procedure model to generate arbitrary trees of various species is implementation. these are the generation of the low level data elements, specification of input parameter requirements, and a brief explanation of the algorithmic structure. terrain images rendered by this process are included, as are diagrams and illustrations explaining the procedure model organization. comparisons with previous work are made.  robert marshall rodger wilson wayne carlson
the computation of optical flow  two-dimensional image motion is the projection of the three-dimensional motion of objects, relative to a visual sensor, onto its image plane. sequences of time-orderedimages allow the estimation of projected two-dimensional image motion as either instantaneous image velocities or discrete image displacements. these are usually called the optical flow field or the image velocity field. provided that optical flow is a reliable approximation to two- dimensional image motion, it may then be used to recover the three-dimensional motion of the visual sensor (to within a scale factor) and the three- dimensional surface structure (shape or relative depth) through assumptions concerning the structure of the optical flow field, the three- dimensional environment, and the motion of the sensor. optical flow may also be used to perform motion detection, object segmentation, time-to-collision and focus of expansion calculations, motion compensated encoding, and stereo disparity measurement. we investigate the computation of optical flow in this survey: widely known methods for estimating optical flow are classified and examined by scrutinizing the hypothesis and assumptions they use. the survey concludes with a discussion of current research issues.  s. s. beauchemin j. l. barron
model-based recognition in robot vision  this paper presents a comparative study and survey of model-based object- recognition algorithms for robot vision. the goal of these algorithms is to recognize the identity, position, and orientation of randomly oriented industrial parts. in one form this is commonly referred to as the "bin- picking" problem, in which the parts to be recognized are presented in a jumbled bin. the paper is organized according to 2-d, 2½-d, and 3-d object representations, which are used as the basis for the recognition algorithms. three central issues common to each category, namely, feature extraction, modeling, and matching, are examined in detail. an evaluation and comparison of existing industrial part- recognition systems and algorithms is given, providing insights for progress toward future robot vision systems.  roland t. chin charles r. dyer
evolving virtual creatures  this paper describes a novel system for creating virtual creatures that move and behave in simulated three-dimensional physical worlds. the morphologies of creatures and the neural systems for controlling their muscle forces are both generated automatically using genetic algorithms. different fitness evaluation functions are used to direct simulated evolutions towards specific behaviors such as swimming, walking, jumping, and following.  a genetic language is presented that uses nodes and connections as its primitive elements to represent directed graphs, which are used to describe both the morphology and the neural circuitry of these creatures. this genetic language defines a hyperspace containing an indefinite number of possible creatures with behaviors, and when it is searched using optimization techniques, a variety of successful and interesting locomotion strategies emerge, some of which would be difficult to invent or built by design.  karl sims
illustrating smooth surfaces  we present a new set of algorithms for line-art rendering of smooth surfaces. we introduce an efficient, deterministic algorithm for finding silhouettes based on geometric duality, and an algorithm for segmenting the silhouette curves into smooth parts with constant visibility. these methods can be used to find all silhouettes in real time in software. we present an automatic method for generating hatch marks in order to convey surface shape. we demonstrate these algorithms with a drawing style inspired by a topological picturebook by g. francis.  aaron hertzmann denis zorin
a note on clustering modules for floorplanning  many vlsi floorplanners work by recursively decomposing rectangular modules into lower-level rectangular modules until the leaf-level modules are reached[5]. good layouts require good floorplans. the quality of a floorplan depends (among other things) on how the leaf-level modules are clustered into the various levels of the hierarchy. some of the factors that determine the suitability of a decomposition are the geometry of the modules, the connectivity among modules, and timing constraints. our experience with the mechanization of a vlsi design manager[1] has shown that the initial structural hierarchy that arises during synthesis from behavioral specifications is not always suitable for floorplanning. we describe hierarchical-clustering-based algorithms that lead to a small number of superior candidate hierarchies.  j. d. gabbe p. a. subrahmanyam
an expert system for foreign currency hedging (abstract only)  international corporations present their financial statements in terms of a single currency, often based on the currency of the home office or on the dollar, even though a large part of their foreign operations are completed using other currencies. unanticipated moves in the volatile foreign exchange markets can severely distort the year-end results, sometimes causing large losses in an otherwise profitable year. recent innovations in the markets for foreign currency futures and options allow corporations to implement complex hedging strategies to reduce foreign exchange risk. a good hedging strategy requires both a statistical analysis and expert judgment as to how to combine this analysis with specific corporate foreign currency demands and the desire for reduced risk. this paper is a progress report on our attempt to build an expert system to make decisions on hedging strategies that reduce foreign exchange risk. in original aspect of our approach is that we will analyze the reactions of experts to a simulated market to determine the rules in our knowledge base. the expert system's performance will be verified by analyzing its decisions in a simulated market.  spencer star
anisotropic diffusion for monte carlo noise reduction  monte carlo sampling can be used to estimate solutions to global light transport and other rendering problems. however, a large number of observations may be needed to reduce the variance to acceptable levels. rather than computing more observations within each pixel, if spatial coherence exists in image space it can be used to reduce visual error by averaging estimators in adjacent pixels. anisotropic diffusion is a space-variant noise reduction technique that can selectively preserve texture, edges, and other details using a map of image coherence. the coherence map can be estimated from depth and normal information as well as interpixel color distance. incremental estimation of the reduction in variance, in conjunction with statistical normalization of interpixel color distances, yields an energy- preserving algorithm that converges to a spatially nonconstant steady state.  michael d. mccool
speedup of a sparse system simulation  _optimistic and conservative simulation algorithms have been effective for speeding up the execution of many simulation programs. event stepped techniques have also been shown to be effective for certain types of problems. this paper presents a conjecture that sparse systems are effectively simulated by conservative and optimistic techniques, where sparseness is characterized by the ratio of output generating states to non-output generating states. the speedup results for a representative sparse simulation are shown to support this conjecture._  james nutaro hessam sarjoughian