waashk/acm huggingface dataset:
selection using a one-eyed cursor in a fish tank vr environment  this study investigates the use of a 2d cursor presented to one eye for target selection in fish tank vr and other stereo environments. it is argued that 2d selection of 3d objects should be less difficult than 3d selection. vision research concerning binocular rivalry and the tendency we have to project images onto surfaces suggests that this mode of viewing will not seem particularly unnatural. a fitt's law experiment was done to directly compare target acquisition with a one-eyed 2d cursor and target acquisition using a 3d cursor. in both cases we used the same input device (polhemus fastrak) so that the device lag and gain parameters were exactly matched. the results show a large improvement in target acquisition time using the 2d cursor. the practical implications of this is that the 2d selection method using a one- eyed cursor in preferable to the 3d selection method. theoretical implications relate to methods for extending fitts' law from the one-dimensional task for which it was designed to 2d and 3d tasks. we conclude that the existing approaches to this problem are not adequate.  colin ware kathy lowther
global illumination using local linear density estimation  this article presents the density estimation framework for generating view- independent global illumination solutions. it works by probabilistically simulating the light flow in an environment with light particles that trace random walks origination at luminaires and then using statistical density estimation techniques to reconstruct the lighting on each surface. by splitting the computation into separate transport and reconstruction stages, we gain many advantages including reduced memory usage, the ability to simulate nondiffuse transport, and natural parallelism. solutions to several theoretical and practical difficulties in implementing this framework are also described. light sources that vary spectrally and directionally are integrated into a spectral particle tracer using nonuniform rejection. a new local linear density estimation technique eliminates boundary bias and extends to arbitrary polygons. a mesh decimation algorithm with perceptual calibration is introduced to simplify the gouraud-shaded representation of the solution for interactive display.  bruce walter philip m. hubbard peter shirley donald p. greenberg
clamping: a method of antialiasing textured surfaces by bandwidth limiting in object space  an object space method is given for interpolating between sampled and locally averaged signals, resulting in an antialiasing filter which provides a continuous transition from a sampled signal to its selectively dampened local averages. this method is applied to the three standard euclidean dimensions and time, resulting in spatial and frame to frame coherence. the theory allows filtering of a variety of functions, including continuous and discrete representations of planar texture.  alan norton alyn p. rockwood philip t. skolmoski
designing computer simulation experiments  this tutorial focuses on that part of a simulation study concerning setting the various specific model parameters and the experimental conditions under which the model will be exercised. other issues in setting up and designing simulation experiments, such as variance reduction, ranking and selection, and optimization, are also mentioned. the focus is on careful choice of such parameters beforehand, with an eye toward the statistical analysis of the simulation's results. output analysis is not treated per se, being covered in another tutorial in this conference (by gordon clark), but the design and analysis activities must be done hand in hand.  w. david kelton
learning to reason  we introduce a new framework for the study of reasoning. the learning (in order) to reason approach developed here views learning as an integral part of the inference process, and suggests that learning and reasoning should be studied together.  the learning to reason framework combines the interfaces to the world used by known learning models with the reasoning task and a performance criterion suitable for it. in this framework, the intelligent agent is given access to its favorite learning interface, and is also given a grace period in with it can interact with this interface and construct a representation kb of the world w. the reasoning performance is measured only after this period, when the agent is presented with queries α from some query language, relevant to the world, and has to answer whether w implies α.  the approach is meant to overcome the main computational difficulties in the traditional treatment of reasoning which stem from its separation from the "world". since the agent interacts with the world when construction its knowledge representation it can choose a representation that is useful for the task at hand. moreover, we can now make explicit the dependence of the reasoning performance on the environment the agent interacts with.  we show how previous results from learning theory and reasoning fit into this framwork and illustrate the usefulness of the learning to reason approach by exhibiting new results that are not possible in the traditional setting. first, we give learning to reason algorithms for classes of propositional languages for which there are no efficient reasoning algorithms, when represented as a traditional (formula-based) knowledge base. second, we exhibit a learning to reason algorithm for a class of propositional languages that is not know to be learnable in the traditional sense.  roni khardon dan roth
simulating decorative mosaics  this paper presents a method for simulating decorative tile mosaics. such mosaics are challenging because the square tiles that comprise them must be packed tightly and yet must follow orientations chosen by the artist. based on an existing image and user- selected edge features, the method can both reproduce the image's colours and emphasize the selected edges by placing tiles that follow the edges. the method uses centroidal voronoi diagrams which normally arrange points in regular hexagonal grids. by measuring distances with an manhattan metric whose main axis is adjusted locally to follow the chosen direction field, the centroidal diagram can be adapted to place tiles in curving square grids instead. computing the centroidal voronoi diagram is made possible by leveraging the z-buffer algorithm available in many graphics cards.  alejo hausner
using focus for generating felicitous locative expressions  we are concerned with using discourse focus to generate felicitous natural language responses to "where is"-type queries by a user with respect to a map. in ordinary language this is typically achieved by using a locative expression whose syntax involves using a preposition (such as in or at) and its object (which serves as a reference point). the selection of an appropriate reference point is important when generating such locative expressions. we attempt to use discourse focus to model the user's mental body position in the selection of an appropriate reference point. this enables the user to use body-oriented inference strategies associated with small scale space to make better sense of the overall spatial organization of the geographic entities and the large scale space of which these geographic entities are a part.  s. m. haller s. s. ali
an experience with a prolog-based object-oriented language  this paper presents an experience with a programming language spool which is based on the combination of object-oriented programming and logic programming. this language inherits the capability of knowledge base organization from object- oriented programming and its expressive power from logic programming.  the experience of the application of spool to the program annotation system showed that this combination was quite useful to formalize domain knowledge into declarative data types and make them reusable in different contexts. it also showed the need for further study such as better linguistic support to exploit the full power of this combination.  koichi fukunaga shin-ichi hirose
imbedding gpss in a general purpose programming language  gpss has proven to be an excellent simulation language, but was not designed to perform the logical and computational tasks of a programming language. strategies for improvement can take one of two paths: building adequate analytic constructs into the existing gpss language, or building gpss-like constructs into an existing general purpose programming language. the second choice can be made easier by use of a language-building utility program to translate simulation constructs into the selected programming language. it is also simplified by the fact that some gpss statements (such as input-output and control) may be dropped, since any good programming language will provide native facilities for these functions. such a fusion between the constructs of a good simulation language, and those of a good programming language, provides a far more flexible system than either alone. this paper discusses pl/i gpss, an implementation of gpss in a pl/i environment which uses pl/i variables as transaction variables and permits use of general pl/i expressions for most gpss statement parameters.  jerrold rubin
a hierarchical symptom classification for model based causal reasoning  model based causal reasoning has been widely used for physical systems diagnosis. the system fault is localized with the causal relation of system structure and behavior. in such applications, if the system fault is not localized with the observed behavior, then a subsequent observation is made. this research studies a hierarchical symptom classification for guiding a subsequent observation in model based causal reasoning. the diagnostic symptoms are mapped to the system functional hierarchy and the symptoms are classified by partitioning the functional hierarchy. the dependency relation of symptoms guides subsequent observation. this strategy enhances the control of subsequent observation by hierarchically structuring and classifying the symptoms.  c. lee p. liu s. clark m. y. chiu
alex an expert system for truck loading  an expert system has been built that plans the loading of boxed products into semi-trailer trucks. the system seeks to optimize the volumetric utilization of a trailer while minimizing the likelihood of damage to the products while in transit. it is currently operating in both interactive and batch modes in the production data processing environment of a large manufacturer of household appliances. this paper describes and compares the methods of expert loaders and the expert system, as well as general information about the implementation.  ron lemaster
transportability to other languages: the natural language processing project in the ai program at mcc  we discuss a recently launched, long-term project in natural language processing, the primary concern of which is that natural language applications be transportable among human languages. in particular, we seek to develop system tools and linguistic processing techniques that are themselves language-independent to the maximum extent practical. in this paper we discuss our project goals and outline our intended approach, address some cross- linguistic requirements, and then present some new linguistic data that we feel support our approach.  jonathan slocum carol f. justus
a bayesian batch means methodology for analysis of simulation output  the purpose of this research is to investigate the use of bayesian methodology in the analysis of simulation output. specifically, the bayesian methodology is introduced in the context of the batch means procedure for building a confidence interval for the output mean. we assume that the output process is at steady state or equivalently that the output process is second order stationary. we also assume that the length is fixed at say n. so the output process can be given by x1, x2, ..., xn,a sequence of observations from a continuous state stationary stochastic process with mean m, variance o2x and autocorrelation function {pi}@@@@i l  this bayesian batch means methodology has been thoroughly tested. the five measures of effectiveness suggested in schriber and andrews (1981) are reported for a variety of simulated theoretical output processes. in addition, each run is compared with various batch means procedures.  richard w. andrews thomas j. schriber
the integration of retrieval, reasoning and drafting for refugee law: a third generation legal knowledge based system  we identify an argument to be the basic unit of reasoning of a system that supports the construction of arguments and drafting of determinations in refugee law. collaboration with the refugee review tribunal of australia has led to the development of a framework for argument construction that includes over 200 generic arguments. however, these arguments may not encompass all arguments used in any particular case. the construction of non-generic arguments involves the integration of information retrieval within reasoning. this retrieval is passage based from a wide variety of text sources. the framework also acts as the illocutionary structure in a document drafting process. in conceptualising this system we have found it useful to propose a classification of knowledge based systems in law.  john yearwood andrew stranieri
device-directed rendering  rendering systems can produce images that include the entire range of visible colors. imaging hardware, however, can reproduce only a subset of these colors: the device gamut. an image can only be correctly displayed if all of its colors lie inside of the gamut of the target device. current solutions to this problem are either to correct the scene colors by hand, or to apply gamut mapping techniques to the final image. we propose a methodology called device- directed rendering that performs scene color adjustments automatically. device-directed rendering applies classic minimization techniques to a symbolic representation of the image that describes the relationship of the scene lights and surfaces to the pixel colors. this representation can then be evaluated to produce an image that is guaranteed to be in gamut. although our primary application has been correcting out-of-gamut colors, this methodology can be generally applied to the problem of adjusting a scene description to accommodate constraints on the output image pixel values.  andrew s. glassner kenneth p. fishkin david h. marimont maureen c. stone
adjoint equations and random walks for illumination computation  in this paper we introduce the potential equation that along with the rendering equation forms an adjoint system of equations and provides a mathematical frame work for all known approaches to illumination computation based on geometric optics. the potential equation is more natural for illumination computations that simulate light propagation starting from the light sources, such as progressive radiosity and particle tracing. using the mathematical handles provided by this framework and the random-walk solution model, we present a number of importance sampling schemes for improving the computation of flux estimation. of particular significance is the use of approximately computed potential for directing a majority of the random walks through regions of importance in the environment, thus reducing the variance in the estimates of luminous flux in these regions. finally, results from a simple implementation are presented to demonstrate the high-efficiency improvements made possible by the use of these techniques.  s. n. pattanaik s. p. mudur
tablet-based valuators that provide one, two, or three degrees of freedom  the ability of the user of a graphics system to interactively control the motions of 3-d objects enhances his or her spatial perception and comprehension of those objects. this paper describes several logical devices based on the tablet, each particularly suited to control some type of interactive manipulation of 2-d and 3-d objects in real time. the "turntable" and the "stirrer" convert rotary motion of the tablet pen or puck into values for one-axis rotational control; the "rack", a two-axis device, is used for scaling control; for three-axis rotational control, the tablet-based three- axis trackball is particularly suited.  kenneth b. evans peter p. tanner marceli wein
expert systems seminar  in recent years there has been significant progress in developing computer programs that can perform technical tasks normally thought to require the knowledge, experience and judgment of human specialists. known as expert systems or knowledge-based systems, these programs have achieved high levels of performance at such diverse but specialized tasks as medical diagnosis, mass-spectrum analysis, chemical synthesis, mineral exploration, and computer system configuration.  this seminar will give an overview of the fundamental principles of knowledge representation and plausible inference used in these systems. particular emphasis will be placed on rule-based systems, which provide a particularly attractive, uniform approach to representing and using judgmental knowledge. the following outline summarizes the topics to be covered.  bruce g. buchanan richard o. duda
some patterns of technological change in high-performance computers  high-performance computer technology is undergoing a period of unusually rapid change, and this paper attempts to describe the patterns of these changes in a systematic way. pattern recognition is the basis of technology forecasting, and it is through technology forecasting that we obtain the anticipatory information that allows us to avoid problems and create opportunities. we will first identify the stages in which technological changes occur, and then define "change" as the first derivative of an information function that describes the state of a technology. we then explore the driving forces that cause three generic patterns of technological change: incremental, exponential, and logistic. some areas in high-performance computer technology that are following these patterns are then identified, and a forecast is developed. finally, some limits of high-performance computing are discussed.  j. worlton
a multiprocessor raster display for interactive graphics system design  the design of increasingly complex vlsi circuits and multilayer printed circuit boards have increased the demands on computer aided design methods including interactive graphics systems. earlier minicomputer based systems with direct view storage tube displays lack the processing power and display characteristics that allow high degrees of interactivity and visual discrimination required for high productivity in complex design situations. declining semiconductor ram costs and increasing capabilities of microprocessors have allowed raster display technology to keep pace with the demands of current interactive graphics systems.  the recently introduced lexidata graphics system 8000 combines state of the art color and black and white raster display technology with the latest microprocessor technology to provide a powerful element for the design of interactive graphics systems to meet today's greater needs. the gs8000 includes a very fast schottky display processor to convert vectors to raster and fill areas and a 16 bit microprocessor to service interactive devices and process a world coordinate data base for editing and display. the system hardware off loads a significant processing and memory burden from the host computer allowing the use of a less powerful host or more users on a single host. an extensive software library resident in the graphics system 8000 reduces the software development required of the user allowing him to concentrate on the applications software necessary for the creation, maintenance and non-graphic processing of his design data base on his host computer.  walter m. anderson
temporal difference learning and td-gammon  ever since the days of shannon's proposal for a chess-playing algorithm [12] and samuel's checkers- learning program [10] the domain of complex board games such as go, chess, checkers, othello, and backgammon has been widely regarded as an ideal testing ground for exploring a variety of concepts and approaches in artificial intelligence and machine learning. such board games offer the challenge of tremendous complexity and sophistication required to play at expert level. at the same time, the problem inputs and performance measures are clear-cut and well defined, and the game environment is readily automated in that it is easy to simulate the board, the rules of legal play, and the rules regarding when the game is over and determining the outcome.  gerald tesauro
hierarchically organised formalisations  formalisations to date have tended to ignore a salient feature of statutes: they exhibit a multi-layered logical structure. this, rather than the unsuitability of logic for representing statute law, is at the root of at least some of the knowledge representation problems researchers have uncovered. in addition, the failure of any formalisation to mirror this kind of structure means that it inevitably will be an impoverished translation of the original article.  t. routen
dynamic nurbs with geometric constraints for interactive sculpting  this article develops a dynamic generalization of the nonuniform rational b-spline (nurbs) model. nurbs have become a defacto standard in commercial modeling systems because of their power to represent free-form shapes as well as common analytic shapes. to date, however, they have been viewed as purely geometric primitives that require the user to manually adjust multiple control points and associated weights in order to design shapes. dynamic nurbs, or d-nurbs, are physics-based models that incorporate mass distributions, internal deformation energies, and other physical quantities into the popular nurbs geometric substrate. using d-nurbs, a modeler can interactively sculpt curves and surfaces and design complex shapes to required specifications not only in the traditional indirect fashion, by adjusting control points and weights, but also through direct physical manipulation, by applying simulated forces and local and global shape constraints. d-nurbs move and deform in a physically intuitive manner in response to the user's direct manipulations. their dynamic behavior results from the numerical integration of a set of nonlinear differential equations that automatically evolve the control points and weights in response to the applied forces and constraints. to derive these equations, we employ lagrangian mechanics and a finite- element-like discretization. our approach supports the trimming of d-nurbs surfaces using d-nurbs curves. we demonstrate d-nurbs models and constraints in applications including the rounding of solids, optimal surface fitting to unstructured data, surface design from cross sections, and free-form deformation. we also introduce a new technique for 2d shape metamorphosis using constrained d-nurbs surfaces.  demetri terzopoulos hong qin
consistent mesh parameterizations  a basic element of digital geometry processing algorithms is the establishment of a smooth parameterization for a given model. in this paper we propose an algorithm which establishes parameterizations for a set of models. the parameterizations are called consistent because they share the same base domain and respect features. they give immediate correspondences between models and allow remeshes with the same connectivity. such remeshes form the basis for a large class of algorithms, including principal component analysis, wavelet transforms, detail and texture transfer between models, and _n_-way shape blending. we demonstrate the versatility of our algorithm with a number of examples.  emil praun wim sweldens peter schröder