ppxscal/embedding_network huggingface dataset:
Investigating the Effectiveness of Direction Manipulation of 3D B-Spline Curves Using the Shape-Matching Paradigm
Authors: Stanley Jang, Kellogg S. Booth, David R. Forsey, Peter Graf
Venue:  (1992)

B-splines are one of many spline formulations for representing smooth curves. These formulations are found in a variety of applications, including interactive curve design. Previous research has shown that the B-spline is an effective formulation for this setting. However, a possible drawback for the novice user in using the B-spline is the fact that control vertices may lie far away from the curve, making its manipulation unintuitive. This problem is compounded in three dimensions. A direct manipulation technique, allowing a curve to be manipulated with points that lie on the curve itself, offers an alternative to control vertex manipulation. An experiment was conducted to compare the interactive design of 3D curves using control vertex manipulation of B-spline curves and a particular type of direct manipulation of B-spline curves. The results of the experiment revealed that direct manipulation was significantly faster than control vertex manipulation, without sacrificing accuracy in the shape of the final 3D curve. A general testbed designed for this investigation and related studies of 3D interaction techniques was used to conduct the experiment.
A Ray Tracing Accelerator Based on a Hierarchy of 1D Sorted Lists
Authors: Alain Fournier, Pierre Poulin
Venue:  (1992)

Since the introduction of ray tracing as a rendering technique, several approaches have been proposed to reduce the number of ray/object tests. This paper presents yet another such approach based on a hierarchy of 1D sorted lists. A bounding box aligned with the axes encloses an object. The coordinates of each bounding box are ordered in three sorted lists (one for each axis) and are treated as events. Traversing a scene with a ray consists of traversing each sorted list in order, intersecting an object only when for this object a first event has been encountered (entered) in every dimension before a second event has been encountered (exited) in any dimension. To reduce the number of events (entries and exits) traversed, a hierarchy of sorted lists is constructed from a hierarchy of bounding boxes. The results are favourable for scenes ranging from moderate to high complexity. Further applications of the technique to hardware assist for ray tracing and to collision detection are discussed.
Building a Lexicon from Machine-Readable Dictionaries for ImprovedInformation Retrieval
Authors: Jane T Nutter, Edward A. Fox, Martha W. Evens
Venue:  (1990)

Information retrieval systems have a tremendous potential for contributing to research in virtually all areas. To date, this potential has not been fully realized, largely because of problems with controlling retrieval. One way to viewing these problems is that retrieval systems use keywords as indices to retrieve texts, as opposed to understanding the words in requests. We describe a project for creating a lexicon from machine-readable dictionaries, which information retrieval systems can use to go beyond present indexing methods, bringing the actual performance of such systems closer to their potential.
A UNIFIED APPROACH TO EVALUATION ALGORITHMS FOR MULTIVARIATE POLYNOMIALS
Authors: Suresh Lodha, Ron Goldman
Venue:  (1995)

We present a unified framework for most of the known and a few new evaluation algorithms for multivariate polynomials expressed in a wide variety of bases including the Bezier, multinomial (or Taylor), Lagrange and Newton bases. This unification is achieved by considering evaluation algorithms for multivariate polynomials expressed in terms of L-bases, a class of bases that include the Bezier, multinomial, and a rich subclass of Lagrange and Newton bases. All of the known evaluation algorithms can be generated either by considering recursive evaluation algorithms for L-bases or by examining change of basis algorithms for L-bases. For polynomials of degree $n$ in $s$ variables, the class of recursive evaluation algorithms includes a parallel up recurrence algorithm with computational complexity $O(n^{s+1})$, a nested multiplication algorithm with computational complexity $O(n^s lgn)$ and a ladder recurrence algorithm with computational complexity $O(n^s)$. These algorithms also generate a new generalization of the Aitken-Neville algorithm for evaluation of multivariate polynomials expressed in terms of Lagrange L-bases. The second class of algorithms, based on certain change of basis algorithms between L-bases, include a dual nested multiplication algorithm with computational complexity $O(n^s)$, and a divided difference algorithm, a forward difference algorithm, and a Lagrange evaluation algorithm with computational complexities $O(n^s)$, $O(1)$ and $O(n)$ per point respectively for the evaluation of multivariate polynomials at several points.
Security in the Sanctuary System
Authors: Matthew Hohlfeld, Aditya Ojha, Bennet Yee
Venue:  (2002)

The Sanctuary mobile code system includes security mechanisms for protecting mobile agents from malicious servers as well as mechanisms for protecting mobile agent servers from malicious mobile code. To protect remotely executed mobile code, we integrate several key approaches: (1) security attributes certification to enable mobile code to avoid nodes in the agent-server network that are untrustworthy, as determined by user-centric security policies; (2) forward secure cryptography to improve detection of malicious tampering by servers; and (3) defining separate roles for agent author and agent owner, which justifies restricted delegation and external reference monitors with owner-provided agents to limit potential damage caused by buggy or compromised agent code. Simply put, we enable mobile code to avoid trouble when possible, and to detect trouble when it is unavoidable. We examine security-aware itinerary planning as a means to supplement these approaches, and describe our analysis of this problem. Our server uses well known approaches to defend itself from malicious code, and custom extensions that address the security needs of the mobile code itself. This paper describes our mechanisms and how they are integrated into the Sanctuary mobile code system.
On packet switched networks for on-chip communication
Authors: Shashi Kumar
Venue: Networks on chip (2003)

Designing a system on a chip with large number of cores poses many challenging problems. Designing a flexible on-chip communication network, which can provide the desired bandwidth and can be reused across many applications, is the key problem. In this chapter, we discuss how we can borrow and adapt the concept of packet switched communication from computer networks to design on-chip networks. In this new paradigm, the cores on the chip communicate among themselves by sending packets using a network of switches. We briefly describe the existing proposals, which have come up in the last couple of years. The network is built using a set of identical switches connected in regular topology. The important issues for design of the network are switch design, design of network access by cores and communication protocols. A particular protocol stack, called Nostrum, is described as a case study of protocols for on-chip communication. Ideas and tools can be borrowed from computer networks for evaluating on-chip networks.
Strategies for Introducing Formal Methods into the ADA Life Cycle
Authors: John A. N. Lee, Karl Nyberg
Venue:  (1988)

This is the final report of a short study of the applicability of formal definition techniques to program development activities with specific emphasis on using the programming language Ada. The portion of the study here encompasses three elements: - A review of the various formal defition techniques; - A study of the existing and planned tools in programming development environments; - An examination of life cycle methodologies with the objective of inserting formalized techniques.
R-Simp to PR-Simp: Parallelizing A Model Simplification Algorithm
Authors: Dmitry Brodsky
Venue:  (2000)

As modelling and visualization applications proliferate, there arises a need to simplify large polygonal models at interactive rates. Unfortunately existing polygon mesh simplification algorithms are not well suited for this task because they are either too slow (requiring pre-computation) or produce models that are too poor in quality. Given a multi-processor environment a common approach for obtaining the required performance is to parallelize the algorithm. Many non-trivial issues need to be taken into account when parallelizing a sequential algorithm. We present PR-Simp a parallel model simplification algorithm and the issues involved in parallelizing R-Simp.
An Improved Polynomial Time Algorithm for Computing the Refined Buneman Tree
Authors: V. Berry
Venue:  (1998)

We consider the problem of inferring a tree with positive weight edges on a set X from a dissimilarity measure on X. This problem arises in classification and more precisely in evolutionary biology, where we try to estimate the evolutionary tree, or "phylogeny", of a set of species. Several studies recently put the emphasis on inferring trees containing reliable edges [Berry and Gascuel 98, Rice et al 97]. A method first proposed by Buneman [71] was recently investigated [Berry and Gascuel 98] to obtain a tree containing almost only safe edges. However, this tree is in most cases a conservative estimator of the species'' phylogeny, due to strict constraints imposed on its edges. Moulton and Steel [98] proposed a variant of the Buneman construction to obtain a less conservative tree, whose edges still verify important combinatorial constraints. Bryant and Moulton recently proposed an O(n^6) polynomial time algorithm for this variant of the Buneman construction. We improve this result by providing an O(n^5) algorithm for this problem that relies on an interesting technique similar to a merge sort procedure on quartets. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
Multiresolution Image Segmentation Combining Region and Boundary Information
Authors: A. Bhalerao, R. G. Wilson
Venue:  (1990)

A new approach to image segmentation is presented that integrates region and boundary information within a great framework of Maximum a Posteriori (MAP) estimation and decision theory. The algorithm employs iterative, decision-directed estimation performed on a spatially localised basis but within a multiresolution representation. The use of a multiresolution technique ensures both robustness in noise and efficiency of computation, while the model-based estimation and decision process is both flexible and spatially local, thus avoiding assumptions about global homogeneity or size and number of regions. The method gives accurate segmentations at low signal-to-noise ratios and is shown to be more effective than previous methods in capturing complex region shapes.
Applications of the Probabilistic Neural Network
Authors: Anthony Zaknich, Yianni Attikiouzel
Venue:  (1992)

Specht introduced a one pass learning algorithm called the Probabilistic Neural Network (PNN) for classification, mapping and associative memory. This paper describes how the standard PNN and a modified version was used by CIIPS to develop a number of successful applications for industry and agriculture. Brief introductions to the PNN and modified PNN algorithms are given, as well as summaries of some other applications reported in the literature.
On the Temporal Analysis of Fairness
Authors: D. Gabbay, A. Pnueli, S. Shelah, J. Stavi
Venue:  (1997)

The use of the temporal logic formalism for program reasoning is reviewed. Several aspects of responsiveness and fairness are analyzed, leading to the need for an additional temporal operator: the `until'' operator -U. Some general questions involving the `until'' operator are then discussed. It is shown that with the addition of this operator the temporal language becomes expressively complete. Then two deductive systems DX and DUX are proved to be complete for the languages without and with the new operator respectively.
Globally Convergent Homotopy Algorithms for Nonlinear Systems ofEquations
Authors: Layne T. Watson
Venue:  (1990)

Probability-one homotopy methods are a class of algorithms for solving nonlinear systems of equations that are accurate, robust, and converge from an arbitrary starting point almost surely. These new globally convergent homotopy techniques have been successfully applied to solve Brouwer fixed point problems, polynomial systems of equations, constrained and unconstrained optimization problems, discretizations of nonlinear two-point boundary value problems based on shooting, finite differences, collocation, and finite elements, and finite difference, collocation, and Galerkin approximations to nonlinear partial differential equations. This paper introduces, in a tutorial fashion, the theory of globally convergent homotopy algorithms, describes some computer algorithms and mathematical software, and presents several nontrivial engineering applications.
Development of New Heuristics for the Euclidean Traveling SalesmanProblem
Authors: Thurman W. Tunnell, Lenwood S. Heath
Venue:  (1989)

Many heuristics have been developed to approximate optimal tours for the Euclidean Traveling Salesman Problem (ETSP). While much progress has been made, there are few quick heuristics which consistently produce tours within 4 percent of the optimal solution. This project examines a few of the well known heuristics and introduces two improvements, Maxdiff and Checks. Most algorithms, during tour constrution, add a city to the subtour because the city best satisfies some criterion. Maxdiff, applied to an algorithm, ranks a city according to its effect (based on the algorithm''s criterion) if it is not added to the subtour.
A COMPARISON OF TWO IMPLEMENTATIONS OF THE TOKEN RING PRIORITY FUNCTION
Authors: Ivan Fellner, Ivan Racko, Milos Racek, Karol Fabian, Darrell Long
Venue:  (1992)

System performance is strongly influenced by the quality of its implementations. We describe four ways of evaluating the performance of two implementations of the priority mechanism used in the Token Ring local area network. We use various methods for comparing the small priority machine''s differences and show how a simplified comparison can lead to bad results. With connection to the evaluation complexity, we also consider the simulation cost of the implementation process.
Data extraction for design and construction integration: an application in petrochemical industry
Authors: K. Lueprasert, L. Meepradit
Venue: Proceedings of the eighth international conference on The application of artificial intelligence to civil and structural engineering computing (2001)

This paper discussed and a data-extraction system that integrates design and construction phase of petrochemical plant by transferring electronic data in isometric drawing to the construction phase automatically. The integration eliminates the needs of manual quantity take-off, lessens human errors in this process and expedite the whole operation significantly. First, the knowledge representation of relevant data was developed. The data consists of design and specification data normally contained in a typical isometric drawing and other data that will be later used in the actual construction. Block drawing functions, which works as a drawing block template, was developed using a VBA tool. The functions were developed as add-on functions to the main CAD software. With the drawing functions, relevant pipeline information can be incorporated into each object in an isometric drawing. These data can then be extracted and queried into another database that can be used in various applications during the construction, e.g. procurement, purchasing, construction control and quality inspection. With the CAD data-extraction, project's productivity and efficiency can improve significantly.
PX systems = P systems + X machines
Authors: Francesco Bernardini, Marian Gheorghe, Mike Holcombe
Venue: Natural Computing: an international journal (2003)

The paper is a survey of the main features of P systems, X machines and of a new computational device called PX system. The sequential and the parallel PX systems are presented. Results reflecting the computational power of these models and their effectiveness in solving NP-complete problems are briefly mentioned.
Human-competitive applications of genetic programming
Authors: John R. Koza
Venue: Advances in evolutionary computing: theory and applications (2003)

Genetic programming is an automatic technique for producing a computer program that solves, or approximately solves, a problem. This chapter reviews several recent examples of human-competitive results produced by genetic programming. The examples all involve the automatic synthesis of a complex structure from a high-level statement of the requirements for the structure. The illustrative results include examples of automatic synthesis of both the topology and sizing (component values) for analog electrical circuits, automatic synthesis of placement and routing (as well as topology and sizing) for circuits, and automatic synthesis of both the topology and tuning (parameter values) of controllers.
Randomized Graph Drawing with Heavy-Duty Preprocessing
Authors: D. Harel, M. Sardas
Venue:  (1993)

We present a graph drawing system for general undirected graphs with straight-line edges. It carries out a rather complex set of preprocessing steps, designed to produce a topologically good, but not necesarily nice-looking layout, which is then subjected to Davidson and Harel''s simulated annealing beautification algorithm. The intermediate layout is planar for planar graphs and attempts to come close to planar for nonplanar graphs. The system''s results are significantly better, and much faster, than what the annealing appraoch is able to achieve on its own.
Minimax Resource Allocation with Continuous Variables: The DefinitiveSolution
Authors: Emile K. Haddad
Venue:  (1990)

The necessary and sufficient conditions of local global optimization are derived for constrained resource allocation with continuous variables and objective functions of the forms max (sub i) {f-sub i(x-sub i)} and mini{f-sub i(x-sub i)} where {f-sub i} can be nondifferentiable, nonmonotone, nonconvex, multimodal functions. All previous theoretical results, which are sufficient conditions for global optimization with monotone {f-sub i}, are special, restrictive cases of the new criteria. The powerful criteria also enable complete determination of all the global optimal solutions, thus allowing further lexicographic optimization. The criteria also enable determination of all the local maxima and minima, a previously unaddressed facet of the solution, thus providing illuminating information on the behavior of the objective function and its overall "topography", which could be useful in suboptimal multi-criteria trade-offs. The new results admit a straightforward graphical interpretation and implementation, which facilitates their utilization and extends their applicability to practical problems where {f-sub i} are specified only in graphical formats derived from empirical or simulation data. Except for the mild and practically insignificant restrictions of continuity and "local monomodality" retained on {f-sub i} by the analysis, the results of this paper constitute the complete and definitive solution of the problem.
Ritt Wu''s Decomposition Algorithm and Geometry Theorem Proving
Authors: Shang Chou, Xiao Gao
Venue:  (1990)

An improved Ritt-Wu''s decomposition (of an algebraic set into the union of irreducible varieties) algorithm is given. The algorithm has been used to prove geometric theorems that Wu''s original method addresses. Unlike Wu''s original approach, nondegenerate conditions are given explicitly at the beginning, not generated during the proof process. A program based on this improved version of the algorithm proved more than 500 theorems, including Morley''s trisector theorem.
Convergence of the iterative group-implicit algorithm for parallel transient finite element analysis
Authors: Y. Dere, E. D. Sotelino
Venue: Proceedings of the eighth international conference on The application of artificial intelligence to civil and structural engineering computing (2001)

The scope of the present research is on direct solution algorithms for the integration of the equations of motion arising in structural dynamics problems. In this work, the convergence characteristics of the Iterative Group-Implicit Algorithm (IGI) have been discussed. The convergence and applicability of the IGI algorithm are improved through modifications in the computation of the sub-domain distribution factor and in the mass-averaging rule. The resulting algorithm is called Modified Iterative Group-Implicit Algorithm (MIGI). In this work, the MIGI algorithm is explained in detail step-by-step. The two algorithms IGI and MIGI are compared in terms of their convergence and limitations. An example thirty-storey frame subjected to an earthquake excitation is solved numerically to demonstrate the accuracy and speed-up characteristics of the MIGI algorithm.
Computing Undirected Shortest Paths with Comparisons and Additions
Authors: Seth Pettie, Vijaya Ramachandran
Venue:  (2001)

We study undirected shortest paths problems in a natural model of computation, namely one which gives us two numerical operations: comparisons and additions. This is the model assumed by such standards as Dijkstra''s algorithm, the Bellman-Ford algorithm, and the Floyd-Warshall algorithm, and is the usual model for proving lower bounds on shortest path problems. We present an algorithm for undirected single source shortest paths (SSSP) with arbitrary real edge weights which performs O(SSSP(m, n) + m log a(m, n) +n log log r) comparisons and additions. Here SSSP is the comparison-addition complexity of the problem, r the ratio of the maximum-to-minimum edge length, and a Tarjan''s inverse-Ackermann function. By the usual convention, m and n are the number of edges and vertices respectively. Our algorithm is implementable on a pointer machine with time complexity O(ma (m, n) + n log log r). This represents an improvement over Dijkstra''s algorithm so long as r is less than 2 n o(1). For the undirected all pairs shortest paths (APSP) problem we present an algorithm that runs in time O(mna(m,n) while performing O(mn log a,(m,n)) comparisons and additions. This time bound improves on the best results known for this problem when the input graph is sparse, i.e., when m = o(n log n). Our algorithms make extensive use of the graph''s minimum spanning tree in order to compute SSSP quickly. and our approach is based on a refinement of Thorup''s component hierarchy data structure, which was developed under the more powerful RAM model.
Limits of Indirect Branch Prediction
Authors: Karel Driesen, Urs Holzle
Venue:  (1997)

Indirect branch prediction is likely to become more important in the future because indi rect branches tend to be more frequent in object-oriented programs. With indirect branch prediction misprediction rates of around 25% on current processors, such branches can incur a significant fraction of branch misses even though indirect branches are less frequent than the more predictable conditional branches. We investigate the predictability of indirect branches to determine whether the inferior accuracy of the current indirect branch prediction mechanism (branch target buffers) results from an intrinsic unpredictability of indirect branches or is caused by suboptimal branch prediction hardware. Using programs from the SPECint95 suite as well as a suite of C++ applications, we show that prediction accuracy can exceed 95% on average for these benchmarks, assuming an unlimited hardware budget. This result suggests that better indirect branch prediction hard ware can significantly outperform current branch target buffers.