ppxscal/embedding_network huggingface dataset:
Run-time Techniques for Exploiting Irregular Task Parallelism on Distributed Memory Architectures
Authors: Cong Fu, Tao Yang
Venue:  (1995)

Automatic scheduling for directed acyclic graphs (DAG) and its applications for coarse-grained irregular problems such as large n-body simulation have been studied in the literature. However solving irregular problems with mixed granularities such as sparse matrix factorization is challenging since it requires efficient run-time support for executing the DAG schedule. In this paper, we investigate run-time compilation and supporting techniques for executing general asynchronous DAG schedules on distributed memory machines. Our solution tightly integrates the run-time scheme with a fast communication mechanism to eliminate unnecessary overhead in message buffering and copying, and takes advantage of task dependence properties to ensure the correctness of execution. We demonstrate the applications of this scheme in sparse Cholesky and LU factorizations for which actual speedups have been hard to obtain in the literature. Our experiments on Meiko CS-2 show that the automatically scheduled code achieves scalable performance for these problems and the run-time overhead is small compared to the total execution time.
Constant Time Parallel Indexing of Points in a Triangle
Authors: Simon Kahan, Pierre Kelsen
Venue:  (1994)

Consider a triangle whose three vertices are grid points. Let k denote the number of grid points in the triangle. We describe an indexing of the triangle: a bijective mapping from {0, ..., k-1} to the grid points in the triangle. Computing such a mapping is a fundamental subroutine in fine-grained parallel computation arising in graphics applications such as ray-tracing. We describe a very fast indexing algorithm: after a preprocessing phase requiring time proportional to the number of bits in the vertices of the triangle, a grid point in the triangle can be computed in constant time from its index. The method requires only constant space.
Hopfield Networks as Discrete Dynamical Systems
Authors: Christopher J.S. deSilva, Yianni Attikiouzel
Venue:  (1992)

The analysis of Hopfield networks has been carried out principally by the methods of statistical mechanics and information theory. In this paper, a more geometric approach based on dynamical systems theory is presented. Basic definitions from dynamical systems theory are presented and illustrated with a simple example. The eigenspaces of the weight matrix, the geometry of the energy manifold and the diffeomorphisms induced on the sphere are presented as tools for the study of network dynamics. Topics for further research are proposed.
A Facility for the Display and Manipulation of Dependency Graphs
Venue:  (1988)

A general facility is needed for the display and manipulation of the dependency graphs in these research domains. Such a tool must be extendable to provide all the functionality required in a specific area while preserving generality. This thesis describes the development of the Interactive Dependency Graph Analyzer (IDeA), a graphical tool that meets these requirements. 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 Retargetable Integrated Code Improver
Authors: Manuel E. Benitez, Jack W. Davidson
Venue:  (1993)

We present a retargetable, machine-level framework that tightly integrates the three primary functions performed by an optimizer: code generation, register allocation and code improvements. This framework is highly retargetable, able to fully exploit unique architectural features and, unlike most integrated frameworks, easily extended to include a comprehensive set of local and global optimizations. A unique approach to performing transformations improves register allocation, reduces interactions between the code improvement phases and enhances retargetability by eliminating the need to determine an effective phase ordering for each target architecture.
Speeding Up the Douglas-Peucker Line-Simplification Algorithm
Authors: John Hershberger, Jack Snoeyink
Venue:  (1992)

We analyze the line simplification algorithm reported by Douglas and Peucker and show that its worst case is quadratic in n, the number of input points. Then we give a algorithm, based on path hulls, that uses the geometric structure of the problem to attain a worst-case running time proportional to n log_2(n), which is the best case of the Douglas algorithm. We give complete C code and compare the two algorithms theoretically, by operation counts, and practically, by machine timings.
An Approach to the Organization of Knowledge for the Modelling of Converstion
Authors: Gordon I. McCalla
Venue:  (1978)

This report describes an approach to modelling conversation. It is suggested that to succeed at this endeavour, the problem must be tackled principally as a problem in pragmatics rather than as one in language analysis alone. Several progmatic aspects of conversation are delineated and it is shown that the attempt to account for them raises a number of general issues in the representation of knowledge. .br A scheme for resolving some of these issues is presented and given computational description as a set of (non-implemented) LISP-based control structures called $\mid$LISP. Central to this scheme are several different types of objects that encode knowledge and communicate this knowledge by passing messages. One particular kind of object, the pattern expression ($\mid$PEXPR), turns out to be the most versatile. $\mid$PEXPRs can encode an arbitrary amount of procedural or declarative information; are capable, as a by-product of their message passing behaviour, of providing both a context for future processing decisions and a record of past processing decisions; and make contributions to the resolution of several artificial intelligence problems. .br Some examples of typical conversations that might occur in the general context of attending a symphony concert are then explored, and a particular model of conversation to handle these examples is detailed in $\mid$LISP. The model is goal oriented in its behaviour, and, in fact, is described in terms of four main goal levels: higher level non-linguistic goals; scripts directing both sides of a conversation; speech acts guiding one conversant''s actions; and, finally, language level goals providing a basic parsing component for the model. In addition, a place is delineated for belief models of the conversants, necessary if utterances are to be properly understood or produced. The embedding of this kind of language model in a $\mid$LISP base yields a rich pragmatic environment for analyzing conversation.
Early Regulation of Unresponsive Flows
Authors: Anand Rangarajan
Venue:  (1999)

The increasing deployment of unresponsive traffic can cause serious problems on the Internet. By unresponsive traffic, we mean flows that do not reduce their sending rate in response to congestion. The problems include unfairness against competing traffic that employ congestion control and even congestion collapse. In this thesis work, we propose router mechanisms to regulate unresponsive best-effort traffic. The goal of the proposed mechanisms is to drop undeliverable packets - packets that are dropped somewhere in the network before they reach their destination - as close to the periphery of the network as possible. The key ideas of our approach are: (1) edge routers keep track of incoming flows and their arrival rates; (2) core routers use RED (Random Early Detection) for queue management and generate rate-limited source quenches on packet drops to advice sources to reduce their sending rates; and (3) edge routers snoop on source quenches passing through them and use them to control per-flow regulators. Regulators adjust their maximum sending rate using a multiplicative-decrease, additive-increase discipline. A decrease is triggered by the arrival of a source quench; an increase is triggered for every estimated round-trip time period. We examine the impact of these mechanisms for a variety of simulated network topologies and traffic patterns.
FTP-M: An FTP-like Multicast File Transfer Application
Authors: Manamohan Mysore, George Varghese
Venue:  (2001)

Research in Reliable Multicast has focused on providing scalable, semi-reliable delivery of data. Such solutions based on schemes like SRM have proved adequate for multicast delivery of multimedia data or whiteboard applications, but are inadequate for the strict delivery semantics of file transfer. This paper describes a simple application called FTP-M that provides an efficient one-to-many multicast data transfer by simply extending the FTP protocol and user interface. FTP-M relies on a {\em strictly-reliable} Reliable Multicast protocol layer beneath to send data reliably to multiple receivers. In this paper, we describe the design and implementation of FTP-M. We suggest that FTP-M has the potential to be adopted as a standard way to achieve multicast file transfer.
Influence of domain decomposition on solution of equation systems
Authors: J. Kruis, Z. Bittnar
Venue: Proceedings of the eighth international conference on The application of artificial intelligence to civil and structural engineering computing (2001)

The influence of domain decomposition on number of iterations leading to acceptable accuracy is studied in this paper. The usual procedure of the domain decomposition technique consists of the direct method in the first phase which is followed by iterative method for solution of the reduced problem. Influence of shapes of subdomains on the iteration methods is in the center of attention. Several useful rules are mentioned and concluded.
E-commerce concerns: do we need to change some systems?
Authors: Ned Chapin
Venue: Enterprise information systems IV (2003)

For e-commerce to become successful, web sites must become easy for even first-time users to navigate through, and what is presented on the site must be both current and accurate. The customer or supplier (user) must have confidence that interactions and transactions are secure, and are neither more or less than intended by the user. The organization must have confidence that it can still know its users and be immune from denial of service attacks. To make these situations come to fruition, we will need to enhance our enterprise systems and many of the supporting systems.
Programs that Model Themselves
Authors: Iain D. Craig
Venue:  (1997)

Work on reflection has frequently concentrated on programming languages and operating systems. This work either involves the use of tower reflection or meta-object protocols. The subject of this paper is a different form of reflection that is, we believe, more powerful and fundamental than the other kinds. Self modelling is a process that has not received attention in the literature; indeed, we believe that we are the first to study the topic in a systematic fashion. We will explain the concept of a self-modelling program and describe some example programs that construct and manipulate models of themselves. The programs that we consider are: a learning program, a conceptual modelling system and a production rule interpreter. We also consider the benefits that are to be gained from engaging in self modelling and we show how the programs that we have described benefit from the additional work required of them. We indicate how additional power can be derived by engaging in self modelling.
On Approximating Rectangle Tiling and Packing
Authors: S. Khanna, S. Muthukrishnan, M. Paterson
Venue:  (1998)

Our study of tiling and packing with rectangles in two-dimensional regions is strongly motivated by applications in database mining, histogram-based estimation of query sizes, data partitioning, and motion estimation in video compression by block matching, among others. An example of the problems that we tackle is the following: given an n by n array A of positive numbers, find a tiling using at most p rectangles (that is, no two rectangles must overlap, and each array element must fall within some rectangle) that minimizes the maximum weight of any rectangle; here the "weight" of a rectangle is the sum of the array elements that fall within it. If the array A were one-dimensional, this problem could be easily solved by dynamic programming. We prove that in the two-dimensional case it is NP-hard to approximate this problem to within a factor of 1.25. On the other hand, we provide a near-linear time algorithm that returns a solution at most 2.5 times the optimal. Other rectangle tiling and packing problems that we study have similar properties: while it is easy to solve them optimally in one dimension, the two-dimensional versions become NP-hard. We design efficient approximation algorithms for these problems.
How Far Can Nim in Disguise be Stretched?
Authors: U. Blass, A. S. Fraenkel, R. Guelman
Venue:  (1997)

We give a complete answer to the question which moves can be adjoined to the game of nim without changing its winning strategy. The results apply to other combinatorial games with unbounded Sprague-Grundy function values. We formulate two refinements of the notion of nim-sum 0 for proving the results.
Extending and Managing Software Reflexion Models
Authors: Gail C. Murphy, David Notkin, Kevin Sullivan
Venue:  (1997)

The artifacts comprising a software system often "drift" apart over time. Design documents and source code are a good example. The software reflexion model technique was developed to help engineers exploit---rather than remove---this drift to help them perform various software engineering tasks. More specifically, the technique helps an engineer compare artifacts by summarizing where one artifact (such as a design) is consistent with and inconsistent with another artifact (such as source). The use of the technique to support a variety of tasks-including the successful use of the technique to support an experimental reengineering of a system comprising a million lines-of-code-identified a number of shortcomings. In this paper, we present two categories of extensions to the technique. The first category concerns the typing of software reflexion models to allow different kinds of interactions to be distinguished. The second category concerns techniques to ease the investigation of reflexion models. These extensions are aimed at making the engineer more effective in performing various tasks by improving the management and understanding of the inconsistencies---the drift---between artifacts.
Solving Galerkin Approximations to Nonlinear Two-Point Boundary Value Problems by a Globally Convergent Homotopy Method
Authors: Layne T. Watson, L. R Scott
Venue:  (1986)

The Chow-Yorke algorithm, i.e., a homotopy method that has been proved globally convergent j problems, certain classes of zero finding and nonlinear programming problems, and two-point, boundary based on shooting, finite differences, and spline collocation. The method is numerically stable and has been applied to a wide range of practical engineering problems. Here the Chow-Yorke algorithm is proved globally c Galerkin approximations to nonlinear two-point boundary value problems. Several numerical implement are briefly described, and computational results are presented for a fairly difficult, magnet-hydrodynamic problem. Key words. homotopy method, Chow-Yorke algorithm, globally convergent,, two-point boundary value method, finite element method, nonlinear equations
Parallel Depth First Search, Part II: Analysis
Authors: Vipin Kumar, V. N Rao
Venue:  (1988)

This paper presents the analysis of a parallel formulation of depth-first search. At the heart of this parallel formulation is a dynamic work-distribution scheme that divides the work between different processors. The effectiveness of the parallel formulation is strongly influenced by the work-distribution scheme and the target architecture. We introduce the concept of isoefficiency function to characterize the effectiveness of different architectures and work-distribution schemes. Many researchers considered the ring architecture to be quite suitable for parallel depth-first search. Our analytical and experimental results show that hypercube and shared-memory schemes are significantly better. The analysis of previously known work-distribution schemes motivated the design of substantially improved schemes for ring and shared-memory architectures. In particular, we present a work-distribution algorithm which guarantees close to optimal performance on a shared-memory/C-network-with-message-combining architecture (e.g. RP3). Much of the analysis presented in this paper is applicable to other parallel algorithms in which work is dynamically shared between different processors (e.g., parallel divide-and-conquer algorithms). The concept of isoefficiency is useful in characterizing the scalability of a variety of parallel algorithms.
Transformations in High Level Synthesis: Axiomatic Specification and Efficient Mechanical Verification
Authors: P. S Rajan
Venue:  (1994)

In this work, we investigate the specification and mechanical verification of the correctness of transformations used during high level synthesis in hardware design. The high level synthesis system we address here is due, in part, to the SPRITE project at Philips Research Labs. The transformations in this system are used for refinement and optimization of descriptions specified in a signal flow graph language called SPRITE Input Language (SIL). SIL is an intermediate language used during the synthesis of hardware described using languages such as VHDL. Besides being an intermediate language, it also forms the backbone of TRADES synthesis system from University of Twente. SIL has been used in the design of hardware for audio and video applications. We use Prototype Verification System (PVS) from SRI International, to specify and verify the correctness of the transformations. The PVS specification language allows us to investigate the correctness problem using a convenient level of representation. While, the PVS verifier features automatic procedures and interactive verification rules to check properties of specifications. It has permitted us to examine not only the correctness, but also generalization and composition of transformations of SIL. 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
REINAS: REAL-TIME ENVIRONMENTAL INFORMATION NETWORK AND ANALYSIS SYSTEM: PHASE II REQUIREMENTS DEFINITION
Authors: P. E. Mantey, J. J. Garcia-Luna, H. G. Kolsky, D. D.E. Long, A. T. Pang, E. C. Rosen, C. Tang, B. R. Montague, M. D. Abram, W. W. Macy, B. R. Gritton, J. Padman, W. Nuss
Venue:  (1993)

REINAS is a research and development program with the goal of designing, developing and testing an operational prototype system for data acquisition, data management, and visualization. This system is to support the real-time utilization of advanced instrumentation in environmental science where continuous time measurements and improved spatial resolution allow monitoring and understanding environmental phenomena in much greater detail than has previously been possible. The system will also support the retrospective use of integrated environmental data sets. The project is a multi-year effort of the Baskin Center for Computer Engineering and Information Sciences of the University of California, Santa Cruz, in cooperation with environmental scientists from the Naval Postgraduate School (NPS), Monterey Bay Aquarium Research Institute (MBARI), and the Center for Ocean Analysis and Prediction (NOAA/COAP). This report documents the second phase of the REINAS project during which detailed requirements for the system were defined. During this phase the user requirements for the system were sharpened, evaluations of the key components of the system were carried out, and selections of the technologies to be used in the prototype system were made. A project plan for the system is described along with a refined version of the architecture and its subsystems for data collection, data management, processing, and visualization. The objective of this document is to provide project participants and reviewers with a detailed requirements definition of REINAS as it enters the design and prototype implementation phase. It spells out the technologies to be applied, and the plans for implementing the project goals.
Scalable Isosurface Visualization of Massive Datasets on COTS Clusters
Authors: Xiaoyu Zhang, Chandrajit L. Bajaj, William Blanke, Fussell Donald
Venue:  (2001)

Our scalable isosurface visualization solution on a COTS cluster is an end-to-end parallel and progressive platform, from the initial data access to the final display. In this paper we focus on the back end scalability by introducing a fully parallel and out-of-core isosurface extraction algorithm. It partitions the volume data according to its workload spectrum for load balancing and creates an I/0-optimal external interval tree to minimize the number of I/0 operations of loading large data from disk. It achieves scalability by using both parallel processing and parallel disks. Interactive browsing of extracted isosurfaces is made possible by using parallel isosurface extraction and rendering in conjunction with a new specialized piece of image compositing hardware called Metabuffer. We also describe an isosurface compression scheme that is efficient for isosurface transmission.
Algorithms for the Construction of Invariant Features
Authors: Hanns Schulz-Mirbach
Venue:  (1994)

This paper presents algorithms for the construction of features which are invariant with respect to a given transformation group. The methods are based on integral calculus and are applicable to parametric groups (Lic groups) and finite groups as well. To illustrate the conceprs we discuss in detail how to construct invariant features for the general linear group which is of importance in computer vision applications. We describe how to combine the algorithms with Hilbert space methods for the description of continuous signals
A Parallel Algorithm for Finding Maximal Independent Sets in Planar Graphs
Authors: Norm Dadoun, David G. Kirkpatrick
Venue:  (1987)

The problem of constructing parallel algorithms for finding Maximal Independent Sets in graphs has received considerable attention. In the case that the given graph is planar, the simple efficient parallel algorithm described here may be employed. The method relies on an efficient parallel algorithm for constructing large independent sets in bounded degree graphs. This is accomplished by a simple reduction to the same problem for lists. Using a linear number of EREW processors, the algorithm identifies a maximal independent set in an arbitrary planar graph in O$(\log n \log^{*} n)$ parallel time. A randomized version of the algorithm runs in O$(\log n)$ expected parallel time.
Stiff Stability Considerations for Implicit Runge-Kutta Methods
Authors: James M. Varah
Venue:  (1980)

In this paper, we discuss some recent stiff stability concepts introduced for implicit Runge-Kutta methods, and focus on those properties which are really important from a practical point of view. In particular, the concept of stiff decay is introduced and examined, and applied to the common IRK methods available. The Radau IIA formulas are shown to be particularly useful from this point of view.