waashk/acm huggingface dataset:
on a learnability question associated to neural networks with continuous activations (extended abstract)  this paper deals with learnability of concept classes defined by neural networks, showing the hardness of pac- learning (in the complexity, not merely information-theoretic sense) for networks with a particular class of activation. the obstruction lies not with the vc dimension, which is known to grow slowly; instead, the result follows the fact that the loading problem is np-complete. (the complexity scales badly with input dimension; the loading problem is polynomial-time if the input dimension is constant.) similar and well-known theorems had already been proved by megiddo and by blum and rivest, for binary-threshold networks. it turns out the general problem for continuous sigmoidal-type functions, as used in practical applications involving steepest descent, is not np-hard---there are "sigmoidals" for which the problem is in fact trivial---so it is an open question to determine what properties of the activation function cause difficulties. ours is the first result on the hardness of loading networks which do not consist of binary neurons; we employ a piecewise-linear activation function that has been used in the neural network literature. our theoretical results lend further justification to the use of incremental (architecture-changing) techniques for training networks.  bhaskar dasgupta hava t. siegelmann eduardo sontag
automated argument assistance for lawyers  solving the first of these two drawbacks has led to a new graphical representation of the arguments, in which argument attacks are shown, and to a change in the argumentation theory, viz. the introduction of a novel notion of an argument, viz. that of a dialectical argument. briefly, a dialectical argument is an argument in which attacks (and counterattacks) are incorporated. solving the second drawback has led to the introduction of step warrants and undercutter warrants into the argumentation theory. the resulting notion of a warranted dialectical argument is the analog for defeasible argumentation of the notion of a (hilbert-style) proof of classical logic.  the present version of the argumed-system is put in context by a brief comparison with selected other systems, viz. loui's room 5, gordon and karacapilidis' zeno, argumed's precursor argue! and the previous version of argumed.  bart verheij
legal reasoning - a jurisprudential description  this paper provides a description of a legal reasoning process. the presentation originates from a research project combining law and artificial intelligence (ai) and contains theoretical results from system-developing activities that have been carried out in cooperation with the swedish court administration and a major swedish employer's association. the research project, and several parallel projects at the swedish law and informatics research institute (iri), is being documented in the series iri-reports.  related work, especially focusing on computerized formalization of legal norms and legal decision processes from a jurisprudential perspective is carried out at the norwegian research center for computers and law, but contributions have also been made by many others1 and legal reasoning has been investigated from somewhat different perspectives2.  p. wahlgren
the di-3000 implementation of the 1979 gspc 'core' graphics standard  di-3000 is a machine-independent system of fortran-callable subroutines based on the 1979 'core' report of the graphics standards planning committee (gspc) of acm/siggraph.  di-3000 supports output level-3 (dynamic output), input level-2 (synchronous input), and dimension level-2 (3d) of the core. this includes the complete support of 2d and 3d primitives, full 3d viewing definitions, multiple concurrent display surfaces, hershey text fonts, all logical input functions, and image transformations. the raster extensions defined in the 1979 core report are also supported, including polygonal primitives, shaded or patterned polygons, and dynamic definition of color video lookup tables on raster devices.  di-3000 uses a network of several interconnected virtual graphics devices which communicate with each other via messages. these virtual devices may represent physical graphics devices, graphics metafiles, or device-independent display files for storing retained segments.  the di-3000 logical network may be implemented in various ways, depending on the architecture and operating system of the target computer system. the network concept is ideally suited to multi-tasking or distributed processing environments, where either the central memory of the host computer is limited or the target graphics devices have local intelligence. using a logical network, the virtual graphics devices can execute concurrently for increased efficiency.  all virtual devices have a distinct layer structure. this allows easy maintenance and extension of the system as the graphics standard evolves, without changes in the basic design. the layer structure also makes it easy to build new graphics device drivers.  nikolaus j. kiefhaber james r. warner
constraints in constructive solid geometry  the success of solid modelling in industrial design depends on facilities for specifying and editing parameterized models of solids through user-friendly interaction with a graphical front-end. systems based on a dual representation, which combines constructive solid geometry (csg) and boundary representation (brep), seem most suitable for modelling mechanical parts. typically they accept a csg- compatible input (boolean combinations of solid primitives) and offer facilities for parameterizing and editing part definitions. the user need not specify the topology of the boundary, but often has to solve three-dimensional trigonometric problems to compute the parameters of rigid motions that specify the positions of primitive solids.  a front-end that automatically converts graphical input into rigid motions may be easily combined with boundary-oriented input, but its integration in dual systems usually complicates the editing process and limits the possibilities of parameterizing solid definitions. this report proposes a solution based on three main ideas: (1) enhance the semantics of csg representations with rigid motions that operate on arbitrary collections of sub-solids regardless of their position in the csg tree, (2) store rigid motions in terms of unevaluated constraints on graphically selected boundary features, (3) evaluate constraints independently, one at a time, in user-specified order. the third idea offers an alternative to known approaches, which convert all constraints into a large system of simultaneous equations to be solved by iterative numerical methods.  the resulting front-end is inadequate for solving problems where multiple constraints must be met simultaneously, but provides a powerful tool for specifying and interactively editing parameterized models of mechanical parts and mechanisms. the order in which constraints are evaluated may also be used as a language for specifying the sequence of assembly and set-up operations.  an implementation under way is based on the interpreter of a new object oriented programming language, enhanced with geometric classes. constraint evaluation results in the activation of methods which compute rigid motions from surface information. the set of available methods may be extended by the users, and methods may be integrated in higher level functions whose algorithmic nature simplifies the treatment of degenerate cases. graphic interaction is provided through a geometrical engine which lets the user manipulate shaded images produced efficiently from the csg representation of solid models.  jaroslaw r. rossignac
the global simulation clock as the frequency domain experiment index  frequency domain simulation experiments involve inducing sinusoidal variations in the input process. system sensitivities of the output can be detected in the frequency domain. the selection of an appropriate index for these oscillations is critical in running such experiments. the index for the sinusoidal variations has typically been a discrete index such as customer or part number in queueing and production systems respectively. in this paper, the use of the global simulation clock as the index is discussed.  sheldon h. jacobson doug morrice lee w. schruben
simple constrained deformations for geometric modeling and interactive design  deformations are a powerful tool for shape modeling and design. we present a new model for producing controlled spatial deformations, which we term simple constrained deformations (scodef). the user defines a set of constraint points, giving a desired displacement and radius of influence for each. each constraint point determines a local b-spline basis function centered at the constraint point, falling to zero for points beyond the radius. the deformed image of any point in space is a blend of these basis functions, using a projection matrix computed to satisfy the constraints. the deformation operates on the whole space regardless of the representation of the objects embedded inside the space. the constraints directly influence the final shape of the deformed objects, and this shape can be fine-tuned by adjusting the radius of influence of each constraint point. the computations required by the technique can be done very efficiently, and real-time interactive deformation editing on current workstations is possible.  paul borrel ari rappoport
neural nets for image restoration  no imaging system in practice is perfect, in fact the recorded images are always distorted or of finite resolution. an image recording system can be modeled by a fredholm integral equation of the first kind. an inversion of the kernel representing the system, in the presence of noise, is an ill posed problem. the direct inversion often yields an unacceptable solution. in this paper, we suggest an artificial neural network (ann) architecture to solve ill posed problems in the presence of noise. we use two types of neuron like processing units: the units that use the weighted sum and the units that use the weighted product. the weights in the model are initialized using the eigen vectors of the kernel matrix that characterizes the recording system. we assume the solution to be a sample function of a wide sense stationary process with a known auto- correlation function. as an illustration, we consider two images that are degraded by motion blur.  a. d. kulkarni
an analysis of selected computer interchange color spaces  important standards for device-independent color allow many different color encodings. this freedom obliges users of these standards to choose the color space in which to represent their data. a device-independent interchange color space must exhibit an exact mapping to a colorimetric color representation, ability to encode all visible colors, compact representation for given accuracy, and low computational cost for transforms to and from device- dependent spaces. the performance of cie 1931 xyz, cieluv, cielab, yes, ccir 601-2 ycbcr, and smpte-c rgb is measured against these requirements. with extensions, all of these spaces can meet the first two requirements. quantizing error dominates the representational errors of the tested color spaces. spaces that offer low quantization error also have low gain for image noise. all linear spaces are less compact than nonlinear alternatives. the choice of nonlinearity is not critical; a wide range of gammas yields acceptable results. the choice of primaries for rgb representations is not critical, except that high-chroma primaries should be avoided. quantizing the components of the candidate spaces with varying precision yields only small improvements. compatibility with common image data compression techniques leads to the requirement for low luminance contamination, a property that compromises several otherwise acceptable spaces. the conversion of a device- independent representation to popular device spaces by means of trilinear interpolation requires substantially fewer lookup table entries with ccir 601-2 ycbcr and cielab.  james m. kasson wil plouffe
editorial  i'm very pleased to have the opportunity to take over as editor-in-chief after holly rushmeier's strong leadership of the past three years. acm has made a big effort to get tog back on schedule after the delays caused by changing to a new publication system. with this issue, we are almost on schedule again and the backlog of accepted papers is significantly reduced. i hope to further shorten the time the return reviews to authors and to get accepted paper to readers. as part of that effort, i have asked steve fortune for bell labs, john hart from washington state, joe marks from merl, and jorg peters from the university of florida to be new members of the editorial board to replace those who retired with the end of holly's term.  i expect that we'll see significant changes in the role of journals during my three-year term. right now, journals utilize peer reviews and a revision cycle to provide accreditation to research, but this process is tied to a particular distribution medium and requires financial support in the form of subscription fees. with the increasing use of web-baed publishing, i expect that the accreditation and distribution functions will begin to separate. accreditation will continue to play an important role in scientific reputations and academic careers, while the publication media will become far more diverse. this diversification is particularly important for graphics because many of its important results are not represented well on paper. tog has moved in this direction with a web page that is expertly maintained by eric haines and contains occasional supplemental material (http://www.acm.org./tog/). if tog is to represent the true breadth of graphics, however, we will have to make much more of an effort in this direction.  during the next three years, we will almost certainly see significant changes in graphics as well. clearly, the field is expanding beyond the creation of beautiful and useful images and image sequences.  new emphases include increasingly realistic physical modeling, interactive worlds, and nonvisual modalities. graphics is a fascinating field, in part because researchers are able to adopt and adapt new ideas from so many other fields: art, vision, physics, materials science, control, optimization and biomechanics. i look forward to the innovative and creative work that the community will submit to tog during the next three years.  jessica hodgins
invisibility coherence for faster scan-line hidden surface algorithms  invisibility coherence is a new technique developed to decrease the time necessary to render shaded images by existing scan-line hidden surface algorithms. invisibility coherence is a technique for removing portions of a scene that are not likely to be visible. if a large portion of the scene is invisible, as is often the case in three-dimensional computer graphics, the processing time eliminated may be substantial. invisibility coherence takes advantage of the observation that a minimal amount of processing needs to be done on objects (polygons, patches, or surfaces) that will be hidden by other objects closer to the viewer. this fact can be used to increase the efficiency of current scan-line algorithms, including both polygon-based and parametrically curved surface-based algorithms.  invisibility coherence was implemented and tested with the polygon hidden surface algorithm for constructive solid geometry developed by peter atherton [1]. the use of invisibility coherence substantially increases the efficiency of this scan-line algorithm. invisibility coherence should work as well or even better with other scan-line hidden surface algorithms, such as the lane- carpenter, whitted, and blinn algorithms for parametrically curved surfaces [2]., or the watkins, romney, and bouknight algorithms for polygons [3, 4, 5].  gary a. crocker
deep models, normative reasoning and legal expert systems  this paper discusses the role of deep models and deontic logic in legal expert systems. whilst much research work insists on the importance of both these features, legal expert systems are being built using shallow models and no more propositional logic, and are claimed to be successful in use. there is then a prima facie conflict between findings of research and commercial practice, which this paper explores, and attempts to explain.  t. j. m. bench- capon
application of machine learning to the maintenance of knowledge-based performance  integration of machine learning methods into knowledge- based systems requires greater control over the application of the learning methods. recent research in machine learning has shown that isolated and unconstrained application of learning methods can eventually degrade performance. this paper presents an approach called performance-driven knowledge transformation for controlling the application of learning methods. the primary guidance for the control is performance of the knowledge base. the approach is implemented in the peak system. two experiments with peak illustrate how the knowledge base is transformed using different learning methods to maintain performance goals. results demonstrate the ability of performance-driven knowledge transformation to control the application of learning methods and maintain knowledge base performance.  lawrence b. holder
highly parallel computing in simulation on dynamic bond portfolio management the bond portfolio management problem is formulated as a stochastic program based on interest rate scenarios. it has been proved in dupakova (1998) that small errors in constructing scenarios will not destroy the optimal solution. the aim of the contribution is to quantify, through carefully planned simulation studies, the magnitude of the above-mentioned errors and to give bounds, at a specified confidence level, for the optimal gap between the value related to the optimal first-stage solution of the unperturbed problem and the "true" optimal value. parallel computer numerical results are presented. vittorio moriggia marida bertocchi jitka dupaková
technical implications of proposed graphics standards (panel session)  this panel session is intended to present recent technical developments in the efforts to standardize computer graphics.  several alternative approaches to 3-d standards will be presented and contrasted. the virtual device metafile will be presented, as well as a proposed binding of the gks standard to fortran.  presentations will be made by the following individuals:  dr. peter bono is the chairman of the ansi x3h3 technical committee developing standards for computer graphics programming languages, and will present the current status of the effort to adopt 2-d gks as an international standard and as an american national standard.  tom wright will be available to respond to questions about the programmer's minimal interface to graphics (pmig) proposal, and its current status as a new output level of the draft proposed american national standard (dpans) gks.  mark skall will present a proposed binding of gks to the fortran language. mr. skall will also discuss progress in the field of formal specification of graphics standards and developments in the establishment of conformance/certification procedures for implementations of gks.  theodore reed will present the technical content of the virtual device metafile (vdm) draft proposed american national standard. discussed will be the relationship of the vdm to gks and to the yet to be proposed virtual device interface. specific functionality of the vdm will be discussed as will specific bindings of that functionality as a character set extension and as a binary format.  david shuey will present an overview of the programmer's hierarchical interface to graphics (phigs) proposal. the phigs proposal is intended to support hierarchical structuring of graphics data, in contrast to the core system and gks proposals. this type of structure addresses highly interactive graphics applications which need to modify the presentation and the relationships within graphics data.  richard ehlers will present the attribute model of the phigs proposal and explore the relationship of attribute model to structured graphics data bases. also, mr. ehlers will discuss the viewing and transformation implications of structured graphics data bases using examples.  gunter enderle is a member of the west german delegation to the international standards organization (iso) working group on computer graphics. herr enderle will be discussing iso proposals for the extension of the gks standard from 2-d to 3-d functionality. several such proposals have been made, including one by din (the official standards making body of the german federal republic) and a norwegian proposal called idigs.  elaine sonderegger was a member of the acm siggraph graphics standards planning committee, and is the acm siggraph representative to ansi x3h3. ms. sonderegger will contrast the 3-d functionality of the core system, idigs, din proposed 3-d extensions, and phigs.  david straayer peter bono richard ehlers gunter enderle theodore reed david shuey mark skall elain sonderegger tom wright
circumscription with homomorphisms: solving the equality and counterexample problems  one important facet of common-sense reasoning is the ability to draw default conclusions about the state of the world, so that one can, for example, assume that a given bird flies in the absence of information to the contrary. a deficiency in the circumscriptive approach to common-sense reasoning has been its difficulties in producing default that tweety  blutto using ordinary circumscription, or conclude by default that a particular bird flies, if some birds are known not to fly. in this paper, we introduce a new form of circumscription, based on homomorphisms between models, that remedies these two problems and still retains the major desirable properties of traditional forms of circumscription.  peter k. rathmann marianne winslett mark manasse
multiresolution painting and compositing  we describe a representation for multiresolution images\\---images that have different resolutions in different places---and methods for creating such images using painting and compositing operations. these methods are very easy to implement, and they are efficient in both memory and speed. only the detail present at a particular resolution is stored, and the most common painting operations, "over" and "erase", require time proportional only to the number of pixels displayed. we also show how fractional-level zooming can be implemented in order to allow a user to display and edit portions of a multiresolution image at any arbitrary size.  deborah f. berman jason t. bartell david h. salesin
under the hood of geovrml 1.0  geovrml 1.0 provides geoscientists with a rich suite of enabling capabilities that cannot be found elsewhere. that is, the ability to model dynamic 3-d geographic data that can be distributed over the web and interactively visualized using a standard browser configuration. geovrml includes nodes for vrml97 that perform this task; addressing issues such as coordinate systems, scalability, animation, accuracy, and preservation of the original geographic data. the implementation is released as open source and includes various tools for generating geovrml data. all these facilities provide geoscientists with an excellent medium to present complex 3-d geographic data in a dynamic, interactive, and web-accessible format. we illustrate these capabilities using real-world examples drawn from diverse application areas.  martin reddy lee iverson yvan g. leclerc