waashk/acm huggingface dataset:
the preemption capability in gpss  one of the important capabilities offered by the general purpose simulation language (gpss) is the preemption capability. this capability is of use in modeling many real situations in which it is necessary to interrupt an ongoing activity before it comes to completion on a natural basis, e.g., failure of equipment in a manufacturing context; completion of an input or output activity in a multiprogrammed computing system; routing of roving vehicles, such as police cruisers, to a point of crisis; or simply providing immediate service to a high-priority demand which has occurred. preemption logic is potentially quite complicated, including as it does the need to specify how the interrupted ongoing activity is to be handled, both at the time of preemption and subsequent to that time. this tutorial will explore various aspects of the preemption topic as implemented in gpss.  thomas j. schriber
a new, fast method for 2d polygon clipping: analysis and software implementation  this paper presents a new 2d polygon clipping method, based on an extension to the sutherland-cohen 2d line clipping method. after discussing three basic polygon clipping algorithms, a different approach is proposed, explaining the principles of a new algorithm and presenting it step by step.  an example implementation of the algorithm is given along with some results. a comparison between the proposed method, the liang and barsky algorithm, and the sutherland-hodgman algorithm is also given, showing performances up to eight times the speed of the sutherland-hodgman algorithm, and up to three times the liang and barsky algorithm. the algorithm proposed here can use floating point or integer operations; this can be useful for fast or simple implementations.  patrick-gilles maillot
consistency maintenance in multiresolution simulation  simulations that run at multiple levels of resolution often encounter consistency problems because of insufficient correlation between the attributes at multiple levels of the same entity. inconsistency may occur despite the existence of valid models at each resolution level. cross- resolution modeling (crm) attempts to build effective multiresolution simulations. the traditional approach to crm \---aggregation-disaggregation--- causes chain disaggregation and puts an unacceptable burden on resources. we present four fundamental observations that would help guide future approaches to crm. these observations form the basis of an approach we propose that involves the design of multiple resolution entities (mres). mres are the foundation of a design that incorporates maintaining internal consistency. we also propose maintenance of core attributes as an approach to maintaining internal consistency within an mre..  paul f. reynolds anand natrajan sudhir srinivasan
simpas: a simulation language based on pascal  simpas is a portable, strongly-typed, event-oriented, discrete system simulation language based on pascal. it has most of the useful features of simscript ii.5. however, because of the type checking inherent in simpas, a simpas program is easier to debug and maintain than the corresponding simscript ii.5 program. this paper briefly describes simpas and discusses the advantages of using simpas instead of simscript ii.5 for the rapid construction of reliable simulation programs.  r. m. bryant
analysis of future event set algorithms for discrete event simulation  new analytical and empirical results for the performance of future event set algorithms in discrete event simulation are presented. these results provide a clear insight to the factors affecting algorithm performance, permit evaluation of the hold model, and determine the best algorithm(s) to use. the analytical results include a classification of distributions for efficient insertion scanning of a linear structure. in addition, it is shown that when more than one distribution is present, there is generally an increase in the probability that new insertions will have smaller times than those in the future event set. twelve algorithms, including most of those recently proposed, were empirically evaluated using primarily simulation models. of the twelve tested, four performed well, three performed fairly, and five performed poorly.  william m. mccormack robert g. sargent
illicit expressions in vector algebra  in vector geometry there are 2 distinct types of entities: points p, q, r … and vectors u, v, w … generally, the operattions of vector algebra ---addition, subtraction, scalar multiplication, dot product, and cross product---are intrinsically defined only for vectors, not for points. yet illicit expressions containing terms like p \\+ q, cp, p x q, etc. often appear in graphics textbooks, papers, and programs. in this paper we justify the use of such illicit expressions, and we we give criteria for recognizing when such an expression is truly legitimate. in particular we show that an algebraic expression e(p1, …, pn) is legitimate if and onl y if e(v1 \\+  w, …vn \\+ w) = e( ;v1, …, vn) + kw, k \\+ 0, 1. we also derive many useful examples of such an expression.  ronald n. goldman
the basis of a computer system for modern algebra  so-called general purpose systems for algebraic computation such as altran, macsyma, sac, scratchpad and reduce are almost exclusively concerned with what is usually known as "classical algebra", that is, rings of real or complex polynomials and rings of real or complex functions. these systems have been designed to compute with elements in a fixed algebraic structure (usually the ring of real functions). typical of the facilities provided are: the arithmetic operations of the ring, the calculation of polynomial gcd's, the location of the zeros of a polynomial; and some operations from calculus: differentiation, integration, the calculation of limits, and the analytic solution of certain classes of differential equations. for brevity, we shall refer to these systems as ca systems.  john j. cannon
perceptual color spaces for computer graphics  perceptually uniform color spaces can be a useful tool for solving computer graphics color selection problems. however, before they can be used effectively some basic principles of tristimulus colorimetry must be understood and the color reproduction device on which they are to be used must be properly adjusted. the munsell book of color and the optical society of america (osa) uniform color scale are two uniform color spaces which provide a useful way of organizing the colors of a digitally controlled color television monitor. the perceptual uniformity of these color spaces can be used to select color scales to encode the variations of parameters such as temperature or stress.  gary w. meyer donald p. greenberg
a social reinforcement learning agent  we report on our reinforcement learning work on cobot, a software agent that resides in the well-known online chat community lambdamoo. our initial work on cobot~\cite{cobotaaai} provided him with the ability to collect {\em social statistics\/} and report them to users in a reactive manner. here we describe our application of reinforcement learning to allow cobot to proactively take actions in this complex social environment, and adapt his behavior from multiple sources of human reward. after 5 months of training, cobot received 3171 reward and punishment events from 254 different lambda\\\\-moo users, and learned nontrivial preferences for a number of users. cobot modifies his behavior based on his current state in an attempt to maximize reward. here we describe lambdamoo and the state and action spaces of cobot, and report the statistical results of the learning experiment.  charles isbell christian r. shelton michael kearns satinder singh peter stone
an algorithm for multidimensional data clustering  a new divisive algorithm for multidimensional data clustering is suggested. based on the minimization of the sum-of-squared-errors, the proposed method produces much smaller quantization errors than the median-cut and mean-split algorithms. it is also observed that the solutions obtained from our algorithm are close to the local optimal ones derived by the k-means iterative procedure.  s. j. wan s. k. m. wong p. prusinkiewicz
on solving systems of algebraic equations via ideal bases and elimination theory  the determination of solutions of a system of algebraic equations is still a problem for which an efficient solution does not exist. in the last few years several authors have suggested new or refined methods, but none of them seems to be satisfactory. in this paper we are mainly concerned with exploring the use of buchberger's algorithm for finding groebner ideal bases [2] and combine/compare it with the more familiar methods of polynomial remainder sequences (pseudo-division) and of variable elimination (resultants) [4].  michael e. pohst david y. y. yun
modeling the effect of the atmosphere on light  the interaction of light with particles suspended in the air is the cause of some beautiful effects. among these effects are the colors of the sunset, the blue of the sky, and the appearance of a scene in fog. a lighting model that takes into account the effects of scattering by suspended particles is presented. a method of computing the colors of the sun and sky, for any sun position above the horizon, is derived from the lighting model. the model is also suitable for rendering fog under general lighting conditions. as an example of the use of the model for rendering fog, the special case of fog lit by the sun, without shadows, is considered.  r. victor klassen
texture mapping 3d models of real-world scenes  texture mapping has become a popular tool in the computer graphics industry in the last few years because it is an easy way to achieve a high degree of realism in computer- generated imagery with very little effort. over the last decade, texture- mapping techniques have advanced to the point where it is possible to generate real-time perspective simulations of real-world areas by texture mapping every object surface with texture from photographic images of these real-world areas. the techniques for generating such perspective transformations are variations on traditional texture mapping that in some circles have become known as the image perspective transformation or ipt technology. this article first presents a background survey of traditional texture mapping. it then continues with a description of the texture-mapping variations that achieve these perspective transformations of photographic images of real-world scenes. the style of the presentation is that of a resource survey rather thatn an in-depth analysis.  frederick m. weinhaus venkat devarajan
continuous system simulation languages (cssl's)  this tutorial introduces cssl's (continuous system simulation languages) by using examples from three of the popular commercial languages used in north america at the present time. the languages are cssl-iv (1), dsl/vs (2) and isim (3).  continuous system simulation languages are user- oriented software systems. cssl's are designed to assist engineers and scientists to mathematically model, analyze, and evaluate the dynamic behavior of physical phenomena. by providing a set of tools for computer-aided- analysis, they make it easy for the user to get his simulation on the computer quickly and to easily conduct experiments, collect data and present that data in useful form with minimal knowledge of the computer system itself.  ralph c. huntsinger
applying appearance standards to light reflection models  appearance standards for gloss, haze, and goniochromatic color are applied to computer graphic reflection models. correspondences are derived between both the gloss and haze standards and the specular exponent of the phong model, the surface roughness of the ward model, and the surface roughness of the cook- torrance model. metallic and pearlescent colors are rendered using three aspecular measurements defined in a proposed standard for goniochromatic color. the reflection models for gloss and goniochromatic color are combined to synthesize pictures of clear coated automotive paint. advantages of using appearance standards to select reflection model parameters include the small number of required measurements and the inexpensive commercially available instruments necessary to acquire the data. the use of a standard appearance scale also provides a more intuitive way of selecting the reflection model parameters and a reflection model independent method of specifying appearance.  harold b. westlund gary w. meyer
ray tracing parametric patches  this paper describes an algorithm that uses ray tracing techniques to display bivariate polynomial surface patches. a new intersection algorithm is developed which uses ideas from algebraic geometry to obtain a numerical procedure for finding the intersection of a ray and a patch without subdivision. the algorithm may use complex coordinates for the (u, v)-parameters of the patches. the choice of these coordinates makes the computations more uniform, so that there are fewer special cases to be considered. in particular, the appearance and disappearance of silhouette edges can be handled quite naturally. the uniformity of these techniques may be suitable for implementation on either a general purpose pipelined machine, or on special purpose hardware.  james t. kajiya
picturebalm: a lisp-based graphics language system with flexible syntax and hierarchical data structure  picturebalm is a portable, interactive, lisp-based language system for graphics applications programming. picturebalm's design and initial experimental implementation is described from the point of view of both the user and the language system implementor. the approach of extending a lisp- based language by adding graphical operations was chosen because many of the recognized requirements for graphics programming languages are standard features of lisp-like systems. future work is proposed.  gary b. goates martin l. griss gary j. herron
pertubation analysis - theoretical, experimental, and implementational aspects  perturbation analysis (pa) is a technique for the computation of the gradient of performance measure (pm) of a discrete event dynamic system with respect to its parameters ( ) using only one sample path or monte carlo experiment of the system. it is probably the most developed of the several techniques of single run gradient estimation [1,2,3,4]. there are now close to forty papers on the subject matter.  when first presented, one's immediate reaction to pa has often been incredulity stemming from the belief that "one cannot get something for nothing". later this disbelief may be developed into a more sophisticated and technical objection involving the legitimacy of interchanging differentiation and expectation operators or the probabilistic convergence of the pa estimate to its true value. in less technical terms, these translate to "how can you squeeze out information about a trajectory / sample-path operating under one value of the system parameter from that of another operating under a different value? don't the two trajectories behave entirely dissimilarly?" this is primarily a theoretical and conceptual question for which there are now fairly concrete as well as intuitively pleasing answers. references [4,5] can be consulted for details.  experimentally, pa is ahead of theory in the sense that there are experimental results which we cannot satisfactorily explain. these algorithms are often arrived at via intuitive and heuristic reasoning. we can safely say that the results they produce are not statistical accidents. yet no rigorous proofs are available. a typical example is the case of pa and aggregation in queueing networks. pa can often be successfully applied to the aggregated version of network for which pa is known to fail if applied to the original complex network. another experimental observation is the excellent variance reduction associated with pa calculation of a gradient estimate. these experimental findings, in fact, provide challenges and clues to future theoretical developments. this is in contrast with an axiomatic and purely mathematical development of the subject matter.  lastly, the implementation of pa in simulation and real time setting involve another type of effort. there does not exist a general purpose pa algorithm or routine which is totally data driven and transparent to the user. it is not a trivial exercise to develop such software. yet this author is convinced that this must be carried out if pa is to be really effective in everyday applications.  although the theoretical aspects of the matter have understandibly received the most attention. the other two aspects of experimentation and implementation may be more important in the long run both in terms of utility and long term health of this research topic.  y. c. ho
simscript ii.5 tutorial  this tutorial will highlight an area for which simscript is particularly well- suited, a complex network of dissimilar processes - each described at an appropriate level of detail. this model has been used, with appropriate variations, for applications as widespread as aircraft maintenance modelling, combat system architecture modelling, waterways network modelling, and crude- oil transportation studies. this later application will be used to illustrate the powerful data structuring and model-building techniques of simscript.  edward c. russell
a note on proximity spaces and connection based mereology representation theorems for systems of regions have been ofinterest for some time, and various contexts have been used forthis purpose: mormann [17] has demonstrated the fruitfulness of themethods of continuous lattices to obtain a topologicalrepresentation theorem for his formalisation of whiteheadianontological theory of space; similar results have been obtained byroeper [20]. in this note, we prove a topological representationtheorem for a connection based class of systems, using methods andtools from the theory of proximity spaces. the key novelty is a newproximity semantics for connection relations. dimiter vakarelov ivo duntsch brandon bennett
simulation and animation of an assembly system  a software package was developed for eventual use by manufacturing engineers responsible for the design of an automated assembly loop. the loop consists of a number of cells through which palletized parts flow. a simulation of this system was developed which includes the effects of blocking, machine down times and pallet transport time. in addition to the statistical information usually obtained with any simulation, an animation of the process was also developed which provides the manufacturing engineer with an interactive- graphic environment to examine the dynamic performance of the system.  bahram keramati christine m. kelly-sacks gregory l. tonkay
stability of event synchronisation in distributed discrete event simulation  this paper is concerned with the behaviour of message queues in distributed discrete event simulators. we view a logical process in a distributed simulation as comprising a message sequencer with associated message queues, followed by an event processor. we show that, with standard stochastic assumptions for message arrival and time-stamp processes, the message queues are unstable for conservative sequencing, and for conservative sequencing with maximum lookahead and hence for optimistic resequencing, and for any resequencing algorithm that does not employ interprocessor "flow control". these results point towards certain fundamental limits on the performance of distributed simulation of open queueing networks.  anurag kumar rajeev shorey
advances and trends in the design and construction of algebraic manipulation systems  we compare and contrast several techniques for the implementation of components of an algebraic manipulation system. on one hand is the mathematical-algebraic approach which characterizes (for example) ibm's scratchpad ii. on the other hand is the more ad hoc approach which characterizes many other popular systems (for example, macsyma, reduce, maple, and mathematica). while the algebraic approach has generally positive results, careful examination suggests that there are significant remaining problems, especially in the representation and manipulation of analytical, as opposed to algebraic mathematics. we describe some of these problems, and some general approaches for solutions.  r. j. fateman
isosurface extraction techniques for web-based volume visualization  the reconstruction of isosurfaces from scalar volume data has positioned itself as a fundamental visualization technique in many different applications. but the dramatically increasing size of volumetric data sets often prohibits the handling of these models on affordable low-end single processor architectures. distributed client-server systems integrating high- bandwidth transmission channels and web-based visualization tools are one alternative to attack this particular problem, but therefore new approaches to reduce the load of numerical processing and the number of generated primitives are required. in this paper we outline different scenarios for distributed isosurface reconstruction from large-scale volumetric data sets. we demonstrate how to directly generate stripped surface representations and we introduce adaptive and hierarchical concepts to minimize the number of vertices that have to be reconstructed, transmitted and rendered. furthermore, we propose a novel computation scheme, which allows the user to flexibly exploit locally available resources. the proposed algorithms have been merged together in order to build a platform-independent web-based application. extensive use of vrml and java opengl-bindings allows for the exploration of large-scale volume data quite efficiently.  klaus engel rudiger westermann thomas ertl
letter: a system for personalizing processed text  the need to maintain multiple versions of documents arises in many different situations. for example, software producers may desire to maintain multiple copies of manuals, one for beginners unfamiliar with computers, and another for experienced users. scientists may have to produce reports in two forms, one for management and another for technical personnel. elected officials answering constituents' mail on a particular issue like to be able to tailor their response to the perspective of the letter writer. in general, tailoring computer-generated text to different audiences is an important problem, but one which is scarcely addressed by most text-formatting programs.  letter attacks this problem by providing a high-level language for creating multiple versions. input to letter is in two parts, a profile and a manuscript. letter uses information from the profile to decide how to print each copy requested in the manuscript. the profile consists of information about the readers of the document. the manuscript consists of the text of the document, along with directive expressions. these include directives which cause information to be copied from the profile into the document, conditional expressions which depend on information in the profile, and looping directives which cause multiple copies of the document to be produced.  letter is written in pascal, and is designed to be portable. the initial version has been developed on a pdp-10, but we plan to install it on a small personal computer in the near future.  edward f. gehringer steven r. vegdahl
parallel independent replicated simulation on a network of workstations  parallel independent replicated simulation (pirs) is an effective approach to speed up the simulation processes. in a pirs, a single simulation run is executed by multiple computers in parallel. the statistical properties for a pirs may be affected by the scheduling policies. for an unbiased pirs scheduling policy, a reliable distributed computing environment is required. we consider an unbiased pirs scheduling policy on a distributed platform such as a network of workstations. we observe that including more computing resources may degrade the performance of pirs. simple rules are proposed to select processors for pirs.  yi-bing lin