ppxscal/embedding_network huggingface dataset:
Multi-Language Support in a Program Analysis and Visualization Tool
Authors: Stuart Moskovics
Venue:  (2000)

Restructuring and analyzing software is difficult. Tools that allow programmers to view and plan modifications to existing programs can ease the burden of maintenance and change. Modern software engineering projects often use many different programming languages, including the use of multiple languages in a single project. The StarTool is a program visualization and restructuring tool for software programs. This thesis discusses a method used to improve the Star Diagram''s retargetability features by providing support for understanding multi-language software programs. Our research shows a simple and extendible mechanism to use single-language retargetable program analysis tools for multiple-language analysis.
Characterizations of Random Set-Walks
Authors: Joseph H. T. Wong
Venue:  (2001)

In this thesis, we introduce a new class of set-valued random processes called random set-walk, which is an extension of the classical random walk that takes into account both the nonhomogeneity of the walk''s environment, and the additional factor of nondeterminism in the choices of such environments. We also lay down the basic framework for studying random set-walks. We define the notion of a characteristic tuple as a 4-tuple of first-exit probabilities which characterizes the behaviour of a random walk in a nonhomogeneous environment, and a characteristic tuple set as its analogue for a random set-walk. We prove several properties of random set-walks and characteristic tuples, from which we derive our main result: the long-run behaviour of a sequence of random set-walks, relative to the endpoints of the walks, converges as the length of the walks tend to infinity. 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
On Lower Bound for Short Noncontractible Cycles in Embedded Graphs
Authors: Teresa M Przytycka, J. H. Przytycki
Venue:  (1988)

Let $C_{g,n}$ be a constant such that for each triangulation of a surface of genus $g$ with a graph of $n$ vertices there exists a noncontractible cycle of length at most $C_{g,n}$. Hutchinson in [H87] conjectures that $C(g,n)$ = $O(\sqrt{n/g})$ for $g < 0$. In this paper, we present a construction of a triangulation which disproves this conjecture.
DSC: Scheduling parallel tasks on an unbounded number of processors
Authors: T. Yang, A. Gerasoulis
Venue:  (1994)

We present a low complexity heuristic named the Dominant Sequence Clustering algorithm (DSC) for scheduling parallel tasks on an unbounded number of completely connected processors. The performance of DSC is comparable or even better on average than other higher complexity algorithms. We assume no task duplication and nonzero communication overhead between processors. Finding the optimum solution for arbitrary directed acyclic task graphs (DAGs) is NP-complete. DSC finds optimal schedules for special classes of DAGs such as fork, join, coarse grain trees and some fine grain trees. It guarantees a performance within a factor of two of the optimum for general coarse grain DAGs. We compare DSC with three higher complexity general scheduling algorithms: the ETF by Hwang, Chow, Anger and Lee, Sarkar''s clustering algorithm, and the MD by Wu and Gajski. We also give a sample of important practical applications where DSC has been found useful. Note: To appear in IEEE Trans. on Parallel and Distributed Systems.
Security of Database Systems: Authorization Features and Mechanisms
Authors: Csaba J. Egyhazy
Venue:  (1986)

Database security has become an essential issue in assuring the integrity, protection, and reliability of the data stored in a database management system (DBMS). The authorization mechanism is the component of the database security system which has the primary responsibility of safeguarding the previously defined data and access rules needed for database access control. The data and rules for authorization control assist in the enforcement of access controls regarding the list of authorized users, the data objects which the authorized users are allowed to manipulate, and the operations that these users can perform on these objects. As part of its tasks the authorization mechanism can grant or deny access to any user or group of users as appropriate.
Efficient procedure for stress integration in concrete sections using a Gauss-Legendre quadrature
Authors: J. L. Bonet, P. F. Miguel, M. A. Fernandez, M. L. Romero
Venue: Proceedings of the eighth international conference on The application of artificial intelligence to civil and structural engineering computing (2001)

This paper deals with the implementation of a very accurate and efficient procedure for the resolution of nonlinear reinforced concrete frame structures. It has been developed a method based on a Gauss-Legendre cuadrature for sections with axial and unsymmetrical bending forces, and with any geometric form.The method has been tested in different section types, changing the depth and the inclination angle of the neutral axis. For the proposed algorithm, the definition of the most efficient integration region has been analysed and the results have been compared with the well-known fibber decomposition approach regarding to the accuracy and speed of the computation.
Image Segmentation using an UpWrite
Authors: Paul S Williams, Mike Alder
Venue:  (1996)

This technical reports examines the problem of segmenting images containing relatively large spatially disjoint homogeneous regions. The aim is to make few, if any, assumptions about the contents of the image to perform the initial segmentation which can then easily be adapted for a range of applications. The segmentation should produce a description of each disjoint object according to its characteristics. Ideally this information should sufficiently describe the object so that it can be recreated as well as recognised or classified.
An Algorithm for Straight-Line Drawing of Planar Graphs
Authors: D. Harel, M. Sardas
Venue:  (1995)

We present a new algorithm for drawing planar graphs on the plane. It can be viewed as a generalization of the algorithm of Chrobak and Payne, which in turn, is based on an algorithm by de Fraysseix, Pach and Pollack. Our algorithm improves the previous ones in that it does not require a preliminary triangulation step; triangulation proves problematic in drawing graphs ``nicely", as it has the tendency to ruin the structure of the input graph. The new algorithm retains the positive features of the previous algorithms: It embeds a biconnected graph of n vertices on a grid of size (2n-4)&#x00D7;(n-2) in linear time. We have implemented the algorithm as part of a software system for drawing graphs nicely.
Designing a Testing Strategy for Expert Systems
Authors: Lee A Hite, David P. Miller
Venue:  (1988)

Testing programs with tractable algorithms is one area in which software engineers have made numerous advances over the past few decades. Testing rule-based expert systems, however, is a new area in software engineering which requires new testing techniques. For the most part, traditional software engineering testing strategies assume modular program development. This is assumption impractical to make for expert system development, for the knowledge base of an expert system is quite simply a huge non-modular program. It consists almost entirely of non-ordered, multi-branching decision statements. In traditional programming, the module interfaces are limited and well defined. For rule-based expert systems, the interaction among rules is combinatoric and highly data-driven. Thus, the testing of a completed expert system via traditional path analysis is impractical. The design of a testing strategy for expert systems focuses on the generic phases of expert system development. Briefly, these phases include system definition, incremental system implementation, and system maintenance. Using this simplified breakdown of the expert system development process as a guide, certain testing techniques can be generalized enough to work for any expert system application.
HyperReal: a hypermedia model for mixed reality
Authors: Luis Romero, Nuno Correia
Venue: Proceedings of the fourteenth ACM conference on Hypertext and hypermedia (2003)

This paper describes a generic hypermedia model that is used as a framework for building context aware and mixed reality applications. It can handle different media elements, and it defines a presentation scheme that abstracts several relevant navigation concepts, including link awareness. The model specifies a base structure for the relation between spaces, either real or virtual, and supports contextual mechanisms. Additionally, it establishes a way to correlate real/virtual world objects with information present in the hypermedia graph. It also includes store/replay mechanisms that can be used to repurpose the content in new ways, including storytelling applications. The proposed model is being tested in a gaming and storytelling environment that integrates the real world, media elements and virtual 3D worlds. The paper presents the overall framework, the current implementation and evaluates its usage in the prototype application.
Finding Problems in Knowledge Bases Using Modal Logics
Authors: Ian P. Gent
Venue:  (1991)

In this paper I propose that it is suitable to consider some statements that an expert makes during knowledge elicitation as being statements in a modal logic. This approach gives us several advantages in finding inconsistencies between a knowledge base and an expert''s intuition in her field. I illustrate this approach by using the modal logic VC, a logic of counterfactual conditionals. In an appendix, I give brief details of theorem proving in VC
A HMM/EM Speaker-Independent Isolated Word Recognizer
Authors: Yaxin Zhang, Christopher J.S. deSilva, Yianni Attikiouzel
Venue:  (1992)

This paper presents a scheme of speaker-independent isolated word recognition in which Hidden Markov Modelling is used with Vector Quantization codebooks constructed using the Expectation-Maximization (EM) algorithm for Gaussian mixture models. In comparison with conventional vector quantization (the LBG algorithm), the EM algorithm results in a more reasonable clustering of the speech signal space. This is demonstrated by a higher recgonition accuracy of the system. Three types of feature parameters of the speech signal were used as input data to the system. The effects of using codebooks of different size were also investigated. Finally, the amalgamation of small codebooks for individual words into a large codebook for the system is discussed.
The Client-Server 2-Spanner Problem and Applications to Network Design
Authors: M. Elkin, D. Peleg
Venue:  (1999)

This paper studies the client-server version of the 2-spanner problem. This is a natural generalization of the sparse 2-spanner problem that turns out to be useful for certain network design problems. The paper presents a logarithmic ratio approximation algorithm for this problem. The algorithm and the analysis are extended to the directed client-server 2-spanner problem and to the client-server augmentation 2-spanner problem, establishing a logarithmic approximation ratio for these problems too. The paper also studies the bounded-diameter network design (BDND) problem, and establishes a logarithmic approximation ratio for the problem, using the tools developed for the client-server 2-spanner problem.
SCATTERING-PARAMETER-BASED MACROMODEL FOR TRANSIENT ANALYSIS OF INTERCONNECT NETWORKS WITH NONLINEAR TERMINATIONS (Ph.D. Thesis)
Authors: Haifang Liao
Venue:  (1995)

An efficient method for analyzing general distributed-lumped interconnect networks with linear or nonlinear loads for transient simulation is presented. The method is based on scattering parameter techniques. The reduced-order approximate models of linear networks with multiple inputs and outputs can be obtained in one pass of reduction. Only two operations are used to do circuit reduction. The circuit partition is efficiently combined with the circuit reduction process to speed up the reduction process, decrease the simulation time and achieve the high accuracy using lower order approximation. The partition is very suitable for large interconnect networks with large number of external ports. For transmission line networks, we can easily capture time-of-flight delay explicitly during the reduction, which greatly improves the accuracy of the macromodel. Mixed Exponential Functions (MEFs) are used to approximate the scattering parameters of the macromodel. MEF preserves the high accuracy of Padi approximation and yield a guaranteed stable solution. With recursive convolution formulas, the macromodel has been integrated into SPICE-like simulators. The interconnect networks with nonlinear terminations also can be analyzed by replacing the linear parts with lower order equivalent circuits. We developed a practical circuit reduction method to reduce large RC interconnect networks into lower order equivalent RC circuits. In conjunction with the macromodel with explicit convolution formulas, a CMOS driver model is also presented for the transient analysis and power dissipation analysis. The model takes into account the input slope effects, CMOS nonlinear effects and load interconnect effects. The macromodel and the driver model provide accuracy comparable to that of SPICE, with one or two orders of magnitude less computing time.
Operations of Homogenizing and Heterogenizing inFederated Database Systems
Authors: I. Schmitt
Venue:  (1996)

The federation of heterogeneous database systems is still a challenge for the database system research. A main topic in federated database systems is the process of overcoming the heterogeneity of component schemata and the process of deriving heterogeneous external schemata for global applications. Semantically rich data models increase the complexity of managing heterogeneity. In this paper heterogeneity of component schemata is overcome by homogenizing operations in a semantically poor data model. Heterogeneous external schemata can be derived from the federated schema by heterogenizing operations which are inverse to the homogenizing operations. Due to the homogenizing by decomposing of classes and heterogenizing by composing of classes, flexible schema transformations and integration is possible. 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
A Data Management Strategy for Transportable Natural Language Interfaces
Authors: J. Johnson
Venue:  (1989)

This thesis focuses on the problem of designing a highly portable domain independent natural language interface for standard relational database systems. It is argued that a careful strategy for providing the natural language interface (NLI) with morphological, syntactic, and semantic knowledge about the subject of discourse and the database is needed to make the NLI portable from one subject area and database to another. There has been a great deal of interest recently in utilizing the database system to provide that knowledge. Previous approaches attempted to solve this challenging problem by capturing knowledge from the relational database (RDB) schema, but were unsatisfactory for the following reasons: 1.) RDB schemas contain referential ambiguities which seriously limit their usefulness as a knowledge representation strategy for NL understanding. 2.) Knowledge captured from the RDB schema is sensitive to arbitrary decisions made by the designer of the schema. In our work we provide a new solution by applying a conceptual model for database schema design to the design of a portable natural language interface. It has been our observation that the process used for adapting the natural language interface to a new subject area and database overlaps considerably with the process of designing the database schema. Based on this important observation, we design an enhanced natural language interface with the following significant features: complete independence of the linguistic component from the database component, economies in attaching the natural language and DB components, and sharing of knowledge about the relationships in the subject of discourse for database schema design and NL understanding. 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
System for indexing multi-spectral satellite images for efficient content-based retrieval
Authors: Julio Barros, James French, Worthy Martin, Patrick Kelly
Venue:  (1995)

Current feature-based image databases can typically perform efficient and effective searches on scalar feature information. However, many important features, such as graphs, histograms, and probability density functions, have more complex structure. Mechanisms to manipulate complex feature data are not currently well understood and must be further developed. The work we discuss in this paper explores techniques for the exploitation of spectral distribution information in a feature-based image database. A six band image was segmented into regions and spectral information for each region was maintained. A similarity measure for the spectral information is proposed and experiments are conducted to test its effectiveness. The objective of our current work is to determine if these techniques are effective and efficient at managing this type of image feature data.
Virginia Disc 2: Preparing, Presenting and Retrieving MARC StandardLibrary Data on a CDROM
Authors: Paul B. Quizon, Edward A. Fox
Venue:  (1990)

Most of today''s commercial information storage systems are stilled based on Boolean queries and inverted files despite the recent advances in information retrieval research. This report discusses the creation on the CDROM publication, named Virginia Disc 2, with the intention of comparing two retrieval systems: Micro-VTLS and Personal Librarian. Micro-VTLS belongs to the class of conventional Boolean systems with inverted index files. Personal Librarian uses newer concepts learned from the Syracuse Information Retrieval Experiment (SIRE). The motivation for comparing the two retrieval approaches is to demonstrate the superiority of newer concepts like term weighting, ranking, and similar measurements employed by Personal Librarian. Virginia Disc 2 uses MARC, a widely accepted standard format for communicating library information. The automation of bibliographic information is a prevalent application in libraries and a CDROM implementation using new information retrieval concepts could generate interest in adopting these new approaches. This report discusses a comparison of Micro-VTLS and Personal Librarian in the areas of retrieval speed, recall and precision. This report also reviews the process of preparing the Virginia Disc 2 CDROM. It discusses the considerations, the preparation effort and the final product of sorting MARC library data on a CDROM.
RAY-BASED DATA LEVEL COMPARISONS OF DIRECT VOLUME RENDERING ALGORITHMS
Authors: Kwansik Kim, Alex Pang
Venue:  (1997)

This paper describes and demonstrates the effectiveness of several metrics for data level comparison of direct volume rendering (DVR) algorithms. The focus is not on speed ups from approximations or implementations with parallel or specialized hardware, but rather on means for comparing resulting images. However, unlike image level comparisons, where the starting point is 2D images, the main distinction of data level comparison is the use of intermediate 3D information to produce the individual pixel values during the rendering process. In addition to identifying the location and extent of differences in DVR images, these data level comparisons allow us to explain why these differences arise from different DVR algorithms. Because of the rich variety of DVR algorithms, finding a common framework for developing data level comparison metrics is one of the main challenges and contribution of this paper. In this paper, we report on how ray tracing can be used as a common framework for comparing a class of DVR algorithms. While this paper focuses on comparing different DVR algorithms, we believe that similar metrics and comparison techniques are also useful for volumetric data comparisons. For example, comparison of experimental versus simulated data sets, or forecasted versus observed data sets, etc.
Experimental Design: Input Device Protocols and Collaborative Learning
Authors: Joanna McGrenere, Kori Inkpen, Kellogg Booth, Maria Klawe
Venue:  (1996)

This document outlines an experimental design for a study that investigates peer collaboration in a computer supported learning environment. Sections of this document have been adapted from a CPSC 533b term report by McGrenere et al. (1995) which outlined a similar experimental desgin. In the proposed study we examine different ways of supporting peer colloration which, for the purposes of this study, refers to two students working on a single comptuer playing an electronic game. The standard computer is configured with only one mouse and therefore when two students share a computer they need to share the mouse as well. We want to investigate the impact of adding second mouse to the configuration such that each child would have their own mouse.
Invariants of Chromatic Graphs
Authors: Teresa M Przytycka, J. H. Przytycki
Venue:  (1988)

In the paper we construct abstract algebras which yield invariants of graphs (including graphs with colored edges --- chromatic graphs). We analyse properties of those algebras. We show that various polynomials of graphs are yielded by models of the algebras (including Tutte and matching polynomials). In particular we consider a generalization of Tutte''s polynomial to a polynomial of chromatic graphs. We analyse relation of graph polynomials with recently discovered link polynomials. \n It is known that computing of the Tutte polynomial is NP-hard. We show that a part of Tutte polynomial (and its generalization) can be computed faster than in exponential time.
Unit Tangent Vector Computation for Homotopy Curve Tracking on aHypercube
Authors: Amal Chakraborty, Donald C. S. Allison, Calvin J. Ribbens, Layne T. Watson
Venue:  (1989)

Probability-one homotopy methods are a class of methods for solving nonlinear systems of equations that are globally convergent from an arbitrary starting point. The essence of all such algorithms is the construction of an appropriate homotopy map and subsequent tracking of some smooth curve in the zero set of the homotopy map. Tracking a homotopy curve involves finding the unit tangent vectors at different points along the zero curve. Because of the way a homotopy map is constructed, the unit tangent vector at each point in the zero curve of a homotopy map (symbols) is in the kernel of the Jacobian matrix (symbols). Hence tracking the zero curve of a homotopy map involves finding the kernel of the Jacobian matrix (symbols). The Jacobian matrix (symbols) is a n x (n + 1) matrix with full rank. Since the accuracy of the unit tangent vector is very important, on orthogonal factorization instead of an LU factorization of the Jacobian matrix is computed. Two related factorizations, namely QR and LQ factorization, are considered here. This paper presents computational results showing the performance of several different parallel orthogonal factorization/triangular system solving algorithms on a hypercube. Since the purpose of this study is to find ways to parallelize homotopy algorithms, it is assumed that the matrices are small, dense, and have a special structure such as that of the Jacobian matrix of a homotopy map.