waashk/acm huggingface dataset:
the simulation of a pipelined event set processor  the availability of inexpensive, sophisticated processing elements affords the computer system designer the opportunity to create tailored computer systems for specialized applications. in this paper, the authors present a design for a discrete event simulation computer, in which event set manipulation is performed by a pipelined set of microprocessors. a simulation model for the system is presented and the selection of optimal parameters for the system are discussed. the results of the simulation and suggestions for further research are presented.  john craig comfort anita miller
model evolution: a rotary index table case history  in this paper, an indexed rotary table employed in the assembly of instrument clusters for automobiles is modeled. the purpose of the paper is to illustrate the procedures involved in model development. the evolution and rationale behind various slam ii® models of the indexed rotary table are described. the paper demonstrates that alternative modeling concepts and viewpoints are important, and that modeling procedures and analysis can lead to a greater understanding of the system under study.  a. alan b. pritsker
controllable morphing of compatible planar triangulations two planar triangulations with a correspondence between the pair of vertex sets are compatible (_isomorphic_) if they are topologically equivalent. this work describes methods for morphing compatible planar triangulations with identical convex boundaries in a manner that guarantees compatibility throughout the morph. these methods are based on a fundamental representation of a planar triangulation as a matrix that unambiguously describes the triangulation. morphing the triangulations corresponds to interpolations between these matrices.we show that this basic approach can be extended to obtain better control over the morph, resulting in valid morphs with various natural properties. two schemes, which generate the linear trajectory morph if it is valid, or a morph with trajectories close to linear otherwise, are presented. an efficient method for verification of validity of the linear trajectory morph between two triangulations is proposed. we also demonstrate how to obtain a morph with a natural evolution of triangle areas and how to find a smooth morph through a given intermediate triangulation.
pgvt: an algorithm for accurate gvt estimation  the time warp mechanism uses memory space to save event and state information for rollback processing. as the simulation advances in time, old state and event information can be discarded and the memory space reclaimed. this reclamation process is called fossil collection and is guided by a global time value called global virtual time (gvt). that is, gvt represents the greatest minimum time of the fully committed events (the time before which no rollback will occur). gvt is then used to establish a boundary for fossil collection. this paper presents a new algorithm for gvt estimation called pgvt. pgvt was designed to support accurate estimates of the actual gvt value and it operates in an environment where the communication subsystem does not support fifo message delivery and where message delivery failure may occur. we show that pgvt correctly estimates gvt values and present some performance comparisons with other gvt algorithms.  loy m. d'souza xianzhi fan philip a. wilsey
efficient reinforcement learning  in this paper we propose a new formal model for studying reinforcement learning, based on valiant's pac framework.  in our model the learner does not have direct access to every state of the environment. instead, every sequence of experiments starts in a fixed initial state and the learner is provided with a "reset" operation that interrupts the current sequence of experiments and starts a new one (from the initial state).  we do not require the agent to learn the optimal policy but only a good approximation of it with high probability. more precisely, we require the learner to produce a policy whose expected value from the initial state is ε-close to that of the optimal policy, with probability no less than 1 δ.  for this model, we describe an algorithm that produces such an (ε,δ)-optimal policy for any environment, in time polynomial in n,k,1/ε,1/δ,1/(1 β) and rmax, where n is the number of states of the environment, k is the maximum number of actions in a state, β is the discount factor and rmax is the maximum reward on any transition.  claude-nicolas fiechter
web-based simulation: revolution or evolution?  the nature of the emerging field of web-based simulation is examined in terms of its relationship to the fundamental aspects of simulation research and practice. the presentation, assuming a form of debate, is based on a panel session held at the first international conference on web-based modeling and simulation, which was sponsored by the society for computer simulation during 11-14 january 1998 in san diego, california. while no clear "winner" is evident in this debate, the issues raised here certainly merit ongoing attention and contemplation.  ernest h. page arnold buss paul a. fishwick kevin j. healy richard e. nance ray j. paul
path specification and path coherence  this paper presents an interactive method for specifying a path in space and time through a three- dimensional environment. a sequence is generated by showing the series of views along the path. the sequence is previewed on a vector scope, and after it is interactively refined, each frame is rendered on a raster device. the path is represented by a b-spline to provide smooth, continuous motion. the timing along the path is also defined by a b-spline so that changes in velocity are smooth. the use of "path coherence" is introduced. the utilization of the available data from the a priori temporal and spatial path definition holds great promise for frame to frame coherence. the path coherence can be used to reduce the number of polygons which need to be considered in a viewed environment. this reduction makes the previewing of complex environments appear less cluttered. furthermore, the computational expense of the culling and sorting operations in the visible line/surface determination is reduced. one sample usage of this is a tree-structured partitioned environment where the priority ordering of the environment must be changed only when the path crosses a partition boundary.  kim l. shelley donald p. greenberg
you can't beat the clock: studies in problem solving  this paper has a broad purpose and a narrow purpose. the broad purpose is to teach some general techniques of problem solving, and the narrow purpose is to teach a particular approach to modeling. these purposes are attained by presenting a sequence of three problems and solutions to these problems.  many of the techniques of problem solving presented are taken from, or suggested by, the works of polya (1957, 1973, 1981). readers interested in expanding their problem solving abilities should strongly consider reading these works. the particular modeling viewpoint advocated in this paper is that time-oriented approaches to modeling are frequently preferable to space- oriented approaches. hence, the title of this paper. unfortunately, for most people, space-oriented approaches to modeling are more natural than time- oriented approaches. by emphasizing the advantages of the time-oriented approach, we hope to broaden the perspective of the reader.  james o. henriksen
amalgamating regulation- and case-based advice systems through suggested answers  this paper proposes a method whereby regulation- and case- based systems may be amalgamated in logic-based advice systems through the use of suggested answers, originally used in a non- legal domain. these are based on relationships, declared at the meta-level, between generalized cases and the vague concepts of the regulations; satisfaction of the conditions derived from cases is not, however, seen as implying that the vague concepts hold, merely as being indicative of them. the resulting systems allow the user free interpretation of the vague concepts, but provide help with interpretation, if required, based on the cases; they also provide clear separation of regulations and cases.  d. e. wolstenholme
presidents' forum  computer graphics has been an integral part of the computer environment since the mid-1950's with origins in military, academic and industrial applications.  presidents of several leading computer graphics companies will discuss some of the issues they see facing this dynamic industry. one president believes that the 1980's will belong to the systems integrators because of the rapid rate of change in both technology and the competitive environment. vertical integration will not be a successful strategy for the 1980's.  another president is concerned that industry research analysts are misusing the term "cad/cam" and that, in fact, most of today's cad/cam systems are simply productive drafting systems. he is concerned about the confusion between realistic pictures and solid modelling and about the proper mix of functionality and interactivity.  still another president believes the crucial issues in computer graphics are those that concern users; those that have access to the tools and those of future development of hardware and software to meet their needs. he suggests that only about one to five percent of the potential users have adopted computer graphics. he is concerned about providing increased access to computer graphics facilities and about removing the widespread psychological barrier of "i can't use the computer to do what i want!".  other current issues will also be addressed.  carl machover donald feddersen ralph t. linsalata peter preuss richard n. spann
integrating discourse and domain knowledge for document drafting  document drafting is a key component of legal expertise. effective legal document drafting requires knowledge both of legal domain knowledge and of the structure of legal discourse. automating the task of legal document drafting therefore requires explicit representation of both these types of knowledge. this paper proposes an architecture that integrates these two disparate knowledge sources in a modular architecture under which representation and control are optimized for each task. this architecture is being implemented in docuplanner 2.0, a system for interactive document drafting.  l. karl branting charles b. callaway bradford w. mott james c. lester
image measurement and recognition (abstract only)  images, like snowflakes, come in virtually infinite variety. in this abstract, we will focus our attention on image edge detection and image grammars.  there are three steps in the syntactic method for image recognition [1]:  decompose the images into subimages or primitives  describe the structural relationship among the primitives by some operators  determine a grammar governing the ways of combination of the primitives and the operators  the process of reducing an image to line drawings of boundaries is known as edge detection. several methods have been used so far in this process.  local methods: this category of procedures uses the concept of discrete gradient transformation to detect local intensity (grey level value) variations. a point is classified as belonging to an edge if the discrete gradient exceeds some threshold value.  regional methods: one first considers what a theoretical edge should look like and then finds, for each region, how far from this configuration it is by using a best fit criterion such as the least square one.  global methods: a linear shift invariant filtering operation is performed on the image.  sequential methods: one first finds some elements belonging to an edge and then proceeds from these points onwards in a sequential way in order to find the remaining points belonging to the same edge. this kind of methods is also known as contour following.  heuristic methods: one searches a narrow band between the successive points in the plan and let the program connect them. for instance, dynamic programming may be used for extracting curves in a noisy environment.  dynamic methods: one uses a sequence of thresholds and considers the "stable regions" of darker pixels which have small variation whilst the image is thresholded at different values.  relaxation methods: one considers each pixel and its neighbors simultaneously and iteratively. define a probability for a pixel to belong to some edge class. the probability converges after iterations and determines whether a pixel belongs to the edge class.  images grammars may be classified into one-, two-, or higher dimensional according to the connectivity of primitives can be expressed. early studies borrowed much theoretical construct from the field of formal languages and were mostly concentrated on one-dimensional, that are, string grammars, in which the only relation between primitives is the linear concatenation.  edward t. lee r. t. wu c. c. huang
ontomap: portal for upper-level ontologies currently the evaluation of the feasibility of general-purposeontologies and upper-level models is expensive mostly because oftechnical problems such as different representation formalisms andterminologies used. additionally, there are no formal mappingsbetween the upper-level ontologies that could ease any kind ofstudies and comparisons. we present the ontomap project(http://www.ontomap.org), a project with the pragmatic goal tofacilitate the access, understanding, and reuse of such resources.a semantic framework on the conceptual level is implemented that issmall and easy enough to be learned on-the-fly. we tried to designthe framework so that it captures most of the semantics usuallyencoded in upper-level models. technically, ontomap is a web-siteproviding access to several upper-level ontologies and manualmapping between them. atanas kiryakov kiril iv. simov marin dimitrov
behavioral control for real-time simulated human agents  a system for controlling the behaviors of an interactive human-like agent, and executing them in real-time, is presented. it relies on an underlying model of continuous behavior as well as a discrete scheduling mechanism for changing behavior over time. a multiprocessing framework executes the behaviors and renders the motion of the agents in real- time. finally we discuss the current state of our implementation and some areas of future work.  john p. granieri welton becket barry d. reich jonathan crabtree norman i. badler
replicas - a new continuous system simulation language  a new continuous system simulation language - replicas, the rational, efficient programming language for the implementation of computerized analysis and simulation - is proposed for general engineering, scientific and econometric applications. the use of gear's integration method coupled with a non-linear quasi-newton solver relying on broyden's method results in a reliable and efficient simulation system invoked by a language which requires only that the user define a mathematical model in terms of first-order, ordinary differential equations. extensions to gear's method accommodate discontinuities, extreme stiffness and steady-state within a single evaluation procedure.  peter mclaughlin
sketching with projective 2d strokes  freehand sketching has long had appeal as an artistic medium for conceptual design because of its immediacy in capturing and communicating design intent and visual experience. we present a sketching paradigm that supports the early stages of design by preserving the fluidity of traditional freehand drawings. in addition, it attempts to fill the gap between 2d drawing programs, which have fixed views, and 3d modeling programs that allow arbitrary views. we implement our application as a two- dimensional drawing program that utilizes a projective representation of points --- i.e. points that lie on the surface of a unit sphere centered at the viewpoint. this representation facilitates the production of novel re- projections generated from an initial perspective sketch and gives the user the impression of being immersed in the drawing or space. we describe a method for aligning a sketch drawn outside the system using its vanishing points, allowing the integration of computer sketching and freehand sketching on paper in an iterative manner. the user interface provides a virtual camera, projective grids to guide in the construction of proportionate scenes, and the ability to underlay sketches with other drawings or photographic panoramas.  osama tolba julie dorsey leonard mcmillan
the f-buffer: a rasterization-order fifo buffer for multi-pass rendering  multi-pass rendering is a common method of virtualizing graphics hardware to overcome limited resources. most current multi-pass rendering techniques use the rgba framebuffer to store intermediate results between each pass. this method of storing intermediate results makes it difficult to correctly render partially-transparent surfaces, and reduces the performance of shaders that need to preserve more than one intermediate result between passes. we propose an alternative approach to storing intermediate results that solves these problems. this approach stores intermediate colors (or other values) that are generated by a rendering pass in a fifo buffer as the values exit the fragment pipeline. on a subsequent pass, the contents of the fifo buffer are fed into the top of the fragment pipeline. we refer to this fifo buffer as a fragment- stream buffer (or f-buffer), because this approach has the effect of associating intermediate results with particular rasterization fragments, rather than with an (x,y) location in the framebuffer. implementing an f-buffer requires some changes to current mainstream graphics architectures, but these changes can be minor. we describe the design space associated with implementing an f-buffer, and compare the f-buffer to recirculating pipeline designs. we implement f-buffers in the mesa software renderer, and demonstrate our programmable-shading system running on top of this renderer.  william r. mark kekoa proudfoot
method of displaying optical effects within water using accumulation buffer  a precise shading model is required to display realistic images. recently research on global illumination has been widespread. in global illumination, problems of diffuse reflection have been solved fairly well, but some optical problems after specular reflection and refraction still remain. some natural phenomena stand out in reflected/refracted light from the wave surface of water. refracted light from water surface converges and diverges, and creates shafts of light due to scattered light from particles. the color of the water is influenced by scattering/absorption effects of water molecules and suspensions. for these effects, the intensity and direction of incident light to particles plays an important role, and it is difficult to calculate them in conventional ray-tracing because light refracts when passing through waves. therefore, the pre-processing tracing from light sources is necessary.  the method proposed here can effectively calculate optical effects, shaft of light, caustics, and color of the water without such pre-processing by using a scanline z-buffer and accumulation buffer.  tomoyuki nishita eihachiro nakamae
hybrid sort-first and sort-last parallel rendering with a cluster of pcs  we investigate a new hybrid of sort-first and sort-last approach for parallel polygon rendering, using as a target platform a cluster of pcs. unlike previous methods that statically partition the 3d model and/or the 2d image, our approach performs dynamic, view-dependent and coordinated partitioning of both the 3d model and the 2d image. using a specific algorithm that follows this approach, we show that it performs better than previous approaches and scales better with both processor count and screen resolution. overall, our algorithm is able to achieve interactive frame rates with efficiencies of 55.0% to 70.5% during simulations of a system with 64 pcs. while it does have potential disadvantages in client-side processing and in dynamic data management---which also stem from its dynamic, view-dependent nature---these problems are likely to diminish with technology trends in the future.  rudrajit samanta thomas funkhouser kai li jaswinder pal singh
ontological engineering for b2b e-commerce in this paper we discuss the nature of our overall enterprise tocreate ontologies in the product and service knowledge space forbusiness-to-business (b2b) electronic commerce. we describe onecrucial problem: the mapping problem, i.e., mapping amongontologies, taxonomies, and classification systems, some of whichare more semantically sound and coherent than others. this problemwe consider to be in need of a sustained research program iftenable solutions are to be found, since the lack of a solutionwill preclude widespread adoption of ontologies by the commercialworld. finally, we summarize the general issues we faced andindicate prospective future research. leo obrst robert e. wray howard liu
scalable distributed visualization using off-the-shelf components  this paper describes a visualization architecture for scalable computer systems. the architecture is currently being prototyped for use in beowulf- class clustered systems. a set of opengl frame buffers are driven in parallel by a set of cpus. the visualization architecture merges the contents of these frame buffers by user-programmable associative and commulative combining operations. the system hardware is built from off-the-shelf components including opengl accelerators, field programmable gate arrays (fpgas), and gigabit network interfaces and switches. a second-generation prototype supports 60 hz operation at 1024 × 1024 pixel resolution with interactive latency up to 1000 nodes.  alan heirich laurent moll
filtering edges for gray-scale displays  while simple line-drawing techniques produce "jagged" lines on raster images, more complex anti-aliasing, or filtering, techniques use gray-scale to give the appearance of smooth lines and edges. unfortunately, these techniques are not frequently used because filtering is thought to require considerable computation. this paper presents a simple algorithm that can be used to draw filtered lines; the inner loop is a variant of the bresenham point-plotting algorithm. the algorithm uses table lookup to reduce the computation required for filtering. simple variations of the algorithm can be used to draw lines with different thicknesses and to smooth edges of polygons.  satish gupta robert f. sproull
enabling classification and shading for 3d texture mapping based volume rendering using opengl and extensions  we present a new technique which enables direct volume rendering based on 3d texture mapping hardware, enabling shading as well as classification of the interpolated data. our technique supports accurate lighting for a one directional light source, semi- transparent classification, and correct blending. to circumvent the limitations of one general classification, we introduce multiple classification spaces which are very valuable to understand the visualized data, and even mandatory to comprehensively grasp the 3d relationship of different materials present in the volumetric data. furthermore, we illustrate how multiple classification spaces can be realized using existing graphics hardware.  in contrast to previously reported algorithms, our technique is capable of performing all the above mentioned tasks within the graphics pipeline. therefore, it is very efficient: the three dimensional texture needs to be stored only once and no load is put onto the cpu. besides using standard opengl functionality, we exploit advanced per pixel operations and make use of available opengl extensions.  michael meißner ulrich hoffmann wolfgang straßer