ppxscal/embedding_network huggingface dataset:
Adaptive Parallel Algorithms for the Synthesis of Real-Time Computer Systems
Authors: Ahmad Z. Abualsamid
Venue: Proceedings of the 2nd IEEE International Conference on Engineering of Complex Computer Systems (1996)

Distributed computing systems are widely used in mission-critical real-time application like missile defense systems, aircraft control and sonar applications. Designing a low cost distributed computing system which satisfies all the stringent requirements of a given application is a difficult problem. This problem can be alleviated using Computer-Aided Synthesis (CAS) tools. Due to the large number of design alternatives, the CAS tools are compute intensive and can take a considerably long time even for medium sized real-time applications. In this paper, we describe a set of parallel synthesis algorithms which dynamically adapt to the number of available processors in a parallel computer system to substantially reduce the total turn-around time of the synthesis process. 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
Efficient Randomized Algorithms for Some Geometric Optimization
Authors: K P Agarwal, Micha Sharir
Venue:  (1995)

In this paper we first prove the following combinatorial bound, concerning the complexity of the vertical decomposition of the minimization diagram of trivariate functions: Let $F$ be a collection of $n$ totally or partially defined algebraic trivariate functions of constant maximum degree, with the additional property that, for a given pair of functions $f, f'' \in F$, the surface $f(x,y,z)=f''(x,y,z)$ is $xy$-monotone (actually, we need a somewhat weaker property---see below). We show that the vertical decomposition of the minimization diagram of $F$ consists of $O(n^{3+\varepsilon})$ cells (each of constant complexity), for any $\varepsilon < 0$. In the second part of the paper we present a general technique that yields faster randomized algorithms for solving a number of geometric optimization problems, including (i) computing the width of a point set in $3$-space, (ii) computing the minimum-width annulus enclosing a set of $n$ points in the plane, and (iii) computing the `biggest stick'' inside a simple polygon in the plane. the expected running time of all three algorithms is $O(n^{3/2+\varepsilon})$, for any $\varepsilon<0$. Our algorithm improves and simplifies previous solutions of all three problems.
Matching Multiple Patterns From Right to Left
Authors: Samuel W. Bent
Venue:  (1990)

We address the problem of matching multiple pattern strings against a text string. Just as the Aho-Corasick algorithm generalizes the Knuth-Morris-Pratt single-pattern algorithm to handle multiple patterns, we exhibit two generalizations of the Boyer-Moore algorithm to handle multiple patterns. In order to obtain worst-case time bounds better than quadratic, our algorithms remember some of the previous history of the matching.
Efficient Reachability Testing of Asynchronous Message-Passing Programs
Authors: Yu Lei, Kuo-Chung Tai
Venue: Proceedings of the Eighth International Conference on Engineering of Complex Computer Systems (2002)

An asynchronous message-passing program isnondeterministic. Given the same input, multipleexecutions of P may exercise different send/receiveevent sequences (or SR-sequences) and may evenproduce different results. Such nondeterminacymakes it difficult to determine the correctness of P.Let X be an input of P. Assume that any execution of P with X terminates. Reachability testing ofP with X is to execute, in a systematic manner, allpossible SR-sequences of P with X such that the correctnessof P with X can be determined. The basicidea of reachability testing is described as follows.We first execute P with X nondeterministically tocollect one or more SR-sequences. F or each collectedSR-sequence, we analyze its race conditions andgenerate race variants, which are prefixes of otherSR-sequences. We replay race variants to generatenew SR-sequences. F or each new SR-sequence, werepeat the same process until we eventually executeall possible SR-sequences of P with X. In this paper,we describe an efficient implementation of reachabilitytesting of asynchronous message-passing programs.Our technique deals with partially-orderedSR-sequences and reduces the complexity and redundancy caused by totally-ordered SR-sequences.
Graphical Animation of Parallel Fortran Programs
Authors: C. Pancake, S. Utter
Venue:  (1991)

A tool for visualizing the behavior of parallel Fortran programs is described. PF-View builds on the functionality already provided by IBM''s Parallel Fortran Trace Facility, extending its usefulness by postprocessing the textual trace information to derive a graphical framework on which program behavior is animated. Its design capitalizes on formal and informal studies of how programmers go about parallelizing scientific applications, providing an intuitive representation of program execution. Detailed information on lock/event synchronization and performance analysis, while quickly available through additional windows, is hidden from the casual user to maximize ease and simplicity. Most importantly, the program as the user knows it -- in the form of hierarchically-organized source code -- is constantly available and automatically correlated with the animation to underscore visually the relationship between source statements and run-time actions.
A taxonomy of glyph placement strategies for multidimensional data visualization
Authors: Matthew O. Ward
Venue: Information Visualization (2002)

Glyphs are graphical entities that convey one or more data values via attributes such as shape, size, color, and position. They have been widely used in the visualization of data and information, and are especially well suited for displaying complex, multivariate data sets. The placement or layout of glyphs on a display can communicate significant information regarding the data values themselves as well as relationships between data points, and a wide assortment of placement strategies have been developed to date. Methods range from simply using data dimensions as positional attributes to basing placement on implicit or explicit structure within the data set. This paper presents an overview of multivariate glyphs, a list of issues regarding the layout of glyphs, and a comprehensive taxonomy of placement strategies to assist the visualization designer in selecting the technique most suitable to his or her data and task. Examples, strengths, weaknesses, and design considerations are given for each category of technique. We conclude with some general guidelines for selecting a placement strategy, along with a brief description of some of our future research directions.
Impact Of Low-K On Crosstalk
Authors: F. Saliou, J. L. Mattei
Venue: Proceedings of the 3rd International Symposium on Quality Electronic Design (2002)

With the reduction of distances between wires in deep sub-micron technologies, coupling capacitances are becoming significant. These increasing of capacities cause noises capable of propagating a logical fault. A bad evaluation of the crosstalk could be at the origin of a malfunction of the circuit. Closed-form formulas are particularly efficient to determine design rules. From an analytical expression for crosstalk evaluation, we explore the performance gain through different intra-layer dielectrics, for a given typical geometry of an upper metal level of a deep sub-micron technology. This model can predict that using a low-k dielectric equal to two one can reduce the crosstalk voltage by about 25%, which can be employed on a possible reduction of the space between lines.
Reliable MAC Layer Multicast in IEEE 802.11 Wireless Networks
Authors: Min-Te Sun, Lifei Huang, Anish Arora, Ten-Hwang Lai
Venue: Proceedings of the 2002 International Conference on Parallel Processing (2002)

Multicast/broadcast is an important service primitive in networks. The IEEE 802.11 multicast/broadcast protocol is based on the basic access procedure of Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA). This protocol does not provide any media access control (MAC) layer recovery on multicast/broadcast frames. As a result, the reliability of the multicast/broadcast service is reduced due to the increased probability of lost frames resulting from interference or collisions. In this paper, we propose a reliable Batch Mode Multicast MAC protocol, BMMM, which substentially reduces the number of contention phases, thus considerably reduces the time required for a multicast/broadcast. We then propose a Location Aware Multicast MAC protocol, LAMM, that uses station location information to further improve upon BMMM. Extensive analysis and simulation results validate the reliability and efficiency of our multicast MAC protocols.
Database Management for Distributed, Multimedia, Collaborative-Writing
Authors: Almon W Wear
Venue:  (1994)

Traditional computer applications have been designed to be run by one user at a time who does work in a single medium, such as ASCII text, and very little regard has been given to the fact that people often work together. Single-user computer applications also create barriers to group collaboration and they are normally used only passively by the group to store, retrieve, and present data. If group members need to work on the same item, for example, a document, in most cases they must work in an interleaved fashion to prevent inconsistency. With the recent development of computer networks and the widespread deployment of networked workstations, automating the group writing process for geographically distributed users has become feasible. There is thus growing interest in a new generation of multi-user computer applications which assist groups of people working together, supporting collaboration even if the team members are geographically distributed. These new tools have been categorized under the name of Computer-Supported Cooperative Work (CSCW). Another new field that has emerged over the past few years is that of multimedia. Multimedia applications allow the user to manipulate information in such diverse media as traditional ASCII text, graphical text, graphics, still images, and audio and video communication. A software package which supports distributed, real-time , multimedia CSCW, known as the Distributed Collaborative Writing Aid (DCWA), is introduced. The DCWA has five major parts but the emphasis of this report is on the DCWA''s distributed database, which is crucial to making the entire system work together both logically and consistently. The database''s design and implementation is described from the initial prototype through the second version. The second version''s database is a specialized, distributed program based on the client-server model implemented in C++ running under 4.3BSD Unix. It provides many management capabilities unique for a multimedia CSCW environment, in addition to many conventional database functions.
A logical model of social commitment for agent communication
Authors: Mario Verdicchio, Marco Colombetti
Venue: Proceedings of the second international joint conference on Autonomous agents and multiagent systems (2003)

As part of the goal of developing a genuinely open multiagent system, many efforts are devoted to the definition of a standard Agent Communication Language (ACL). The aim of this paper is to propose a logical framework for the definition of ACL semantics based upon the concept of (social) commitment. Our framework relies on the assumption that agent communication should be analyzed in terms of communicative acts, by means of which agents create and manipulate commitments, provided certain contextual conditions hold. We propose formal definitions of such actions in the context of a temporal logic that extends CTL* with past-directed temporal operators. In the system we propose, called CTL±, time is assumed to be discrete, with no start or end point, and branching in the future. CTL± is then extended to represent actions and commitments; in particular, we formally define the conditions under which a commitment is fulfilled or violated. Finally, we show how our logic of commitment can be used to define the semantics of an ACL.
Algorithms for Polycyclic-by-finite Matrix Groups: Preliminary Report
Authors: Gretchen Ostheimer
Venue:  (1995)

Let R be the ring of integers or a number field. We present several algorithms for working with polycyclic-by-finite subgroups of GL(n,R). Let G be a subgroup of GL(n,R) given by a finite generating set of matrices. We describe an algorithm for deciding whether or not G is polycyclic-by-finite. For polycyclic-by-finite G, we describe an algorithm for deciding whether or not a given matrix is an element of G. We also describe an algorithm for deciding whether or not G is solvable-by-finite, providing an alternative to the algorithm proposed by Beals ([Be1]) for this problem. Baumslag, Cannonito, Robinson and Segal prove that the problem of determining whether or not a finitely generated subgroup of GL(n,Z) is polycyclic-by-finite is decidable and that the problem of testing membership in a polycyclic-by-finite subgroup of GL(n,Z) is also decidable ([BCRS]). In this report we extend these results by describing algorithms which appear to be suitable for computer implementation. Experimentation is needed to determine the range of input for which they are practical. Our method is to first reduce each problem to the corresponding problem for triangularizable matrix groups. The reduction is an easy consequence of the result of Dixon ([Di1]) that subgroups of the p-congruence subgroup of GL(n,Z_p) are connected in the Zariski topology, where Z_p is the ring of p-adic integers for a prime p. We then prove a structure theorem for triangularizable matrix groups that allows us to decide whether or not a matrix group is triangularizable and to reduce the problem of testing membership in a polycyclic, triangularizable matrix group to the corresponding problems for finitely generated abelian matrix groups and for finitely generated unitriangular matrix groups. In the case of an abelian matrix group we can find a presentation for the group, and our membership test can be made constructive. For these results we rely heavily on the work of Ge ([Ge]) concerning algorithms for multiplicative subgroups of a number field. We also rely on an algorithm of Beals ([Be2]) to decide whether or not a triangularizable matrix group is polycyclic.
On the Semigroup of Strongly Connected Automata
Authors: Boleslaw Mikolajczak
Venue:  (1977)

In 1964 Weeg [6] has posed a question asking which semi-groups admit strongly connected automata. The presumed answer was given in 1971 by Oehmke [5] through the following statement: A semigroup admits strongly connected automaton if it has a homomorphic image either a nontrivial finite group or semigroup of the transformations of some right zero semigroup. This theorem can be reformulated as follows: A semigroup is a characteristic semigroup of strongly connected automaton if it has a homomorphic image either a nontrivial finite group or a semigroup of transformations of some right zero semigroup. In this paper the "only if" part of this theorem has been overthrown. Some related problems concerning strongly connectedness of finite automata are also investigated. Key Words and Phrases: semigroup, characteristic semigroup of an automaton, strongly connected automaton.
A World-Wide Web server on a multicomputer system
Authors: Chun-Hsing Wu, Chun-Chao Yeh
Venue: Proceedings of the 1996 International Symposium on Parallel Architectures, Algorithms and Networks (1996)

As the number of people browsing the world-wide web increases explosively, the workload of popular web servers also increases rapidly. A multicomputer system that was designed for I/O intensive applications has been found to be quite suitable for serving as a web server. The system is composed of multiple clusters of multiprocessors interconnected by an interconnection network. The interconnection network is an ATM-like cell-based switching network which can be restructured so that the system can be scaled up to meet the increasing demands of web service. It is also found that the multicomputer system can support video streams effectively. Design of the system as well as porting of web servers on to it are discussed in this paper.
MisSPECulation: partial and misleading use of SPEC CPU2000 in computer architecture conferences
Authors: Daniel Citron
Venue: Proceedings of the 30th annual international symposium on Computer architecture (2003)

A majority of the papers published in leading computer architecture conferences use SPEC CPU2000, or its predecessor SPEC CPU95, which has become the de facto standard for measuring processor and/or memory-hierarchy performance. However, in most cases a subset of the suite's benchmarks are simulated. For example: 27 papers were published in ISCA 2002, 16 used SPEC CINT2000, 4 used the whole suite, and only 3 papers explained their omissions.This paper quantifies the extent of this phenomenon in the ISCA, Micro, and HPCA conferences: 173 papers were surveyed, 115 used benchmarks from SPEC CINT, but only 23 used the whole suite. If this current trend continues, by the year 2005 80% of the papers will use the full CINT2000 suite, a year after CPU2004 shall be announced.We claim that results based upon a subset of a benchmark suite are speculative and conflict with Amdahl's Law. The law implies that we must present the speedup of using the proposed technique on the whole suite. Projecting the law (by statistically supplying values for the missing benchmarks) to several published papers reduces promising results to average ones. Speedups are reduced from 1.42 to 1.16 in one case, from 1.43 to 1.13 in another, and from 1.76 to 1.15 in a third.Finally, we have found that the disregard for CFP2000 is unwarranted in papers that explore the data cache domain, the suite displays a higher data cache miss rate than CINT2000, which is used more frequently.
The Topological Structure of Asynchronous Computability
Authors: Maurice Herlihy, Nir Shavit
Venue:  (1996)

We give necessary and sufficient combinatorial conditions characterizing the tasks that can be solved by asynchronous processes, of which all but one can fail, that communicate by reading and writing a shared memory. We introduce a new formalism for tasks, based on notions from classical algebraic and combinatorial topology, in which a task''s possible input and output values are each associated with high-dimensional geometric structures called simplicial complexes. We characterize computability in terms of the topological properties of these complexes. This characterization has a surprising geometric interpretation: a task is solvable if and only if the complex representing the task''s allowable inputs can be mapped to the complex representing the task''s allowable outputs by a function satisfying certain simple regularity properties. Our formalism thus replaces the ``operational'''' notion of a wait-free decision task, expressed in terms of interleaved computations unfolding in time, by a static ``combinatorial'''' description expressed in terms of relations among topological spaces, allowing us to exploit powerful theorems from the classic literature on algebraic and combinatorial topology. This approach yields the first impossibility results for several long-standing open problems in distributed computing, such as the ``renaming'''' problem of Attiya et al., and the ``$k$-set agreement'''' problem of Chaudhuri.
An algorithm to compute the primitive central idempotents and the Wedderburn decomposition of a rational group algebra
Authors: Aurora Olivieri, Ángel del Río
Venue: Journal of Symbolic Computation (2003)

We present an algorithm to compute the primitive central idempotents and the Wedderburn decomposition of a rational group algebra. This algorithm has been implemented for System GAP, version 4.
DigitEyes: Vision-Based Human Hand Tracking
Authors: James M. Rehg, Takeo Kanade
Venue:  (1993)

Passive sensing of human hand and limb motion is important for a wide range of applications from human-computer interaction to athletic performance measurement. High degree of freedom articulated mechanisms like the human hand are difficult to track because of their large state space and complex image appearance. This article describes a model-based hand tracking system, called DigitEyes, that can recover the state of a 27 DOF hand model from gray scale images at speeds of up to 10 Hz. We employ kinematic and geometric hand models, along with a high temporal sampling rate, to decompose global image patterns into incremental, local motions of simple shapes. Hand pose and joint angles are estimated from line and point features extracted from images of unmarked, unadorned hands, taken from one or more viewpoints. We present some preliminary results on a 3D mouse interface based on the DigitEyes sensor.
Progressive Scheduling for Real-Time Artificial Intelligence Tasks
Authors: Abdel-Illah Mouaddib
Venue: Proceedings of the 2nd IEEE International Conference on Engineering of Complex Computer Systems (1996)

Controlling complex real-world systems which involve hard deadlines using Artificial Intelligence (AI) techniques attracts the interest of several researchers. The difficulty using AI techniques stems from their unpredictable aspect. Most research on "real-time AI" focuses either on restricted AI techniques that have predictable performance characteristics, or on reactive systems where the power of traditional AI is limited. In this paper, we present an intelligent control strategy based on a progressive scheduling algorithm where the duration of tasks is uncertain. This control strategy can meet deadlines while still using unpredictable AI techniques. This control strategy is based on flexible scheduling algorithm to guarantee or trade-off timeliness and the quality of the solution. The performance of this algorithm is compared to another progressive scheduling approach where the uncertainty of duration is ignored.
Constructive Solid Geometry for Triangulated Polyhedra
Authors: Philip M. Hubbard
Venue:  (1990)

Triangulated polyhedra are simpler to process than arbitrary polyhedra for many graphics operations. Algorithms that compute the boundary representation of a constructive solid geometry (CSG) model, however, may perform poorly if the model involves triangulated polyhedral primitives. A new CSG algorithm specifically tailored to triangulated primitives is presented. The key features of this algorithm are its global processing of intersections between polyhedra and its avoidance of ray-casting when classifying polyhedra against one another. The new algorithm is shown to perform substantially better than one published algorithm, and arguments are presented suggesting its benefits over several others in the context of an interactive modeling environment. Keywords: constructive solid geometry, Boolean set operations, solid modeling, polyhedra, triangulation.
Verification of temporal properties of processes in a setting with data
Authors: Jan F Groote, R. Mateescu
Venue:  (1998)

We define a value-based modal mu-calculus, built from first-order formulas, modalities, and fixed point operators parameterized by data variables, which allows to express temporal properties involving data. We interpret this logic over muCRL terms defined by linear process equations. The satisfaction of a temporal formula by a muCRL term is translated to the satisfaction of a first-order formula containing parameterized fixed point operators. We provide proof rules for these fixed point operators and show their applicability on various examples.