ppxscal/embedding_network huggingface dataset:
Reducing Round-Off Error in Chebyshev Pseudospectral Computations
Authors: Ernest E. Rothman
Venue:  (1991)

Spectral methods have become indispensable tools for scientists involved in solving partial differential equations, because they can achieve infinite-order accuracy for problems with smooth data. In order to realize this accuracy in real large-scale applications, one must be able to compute with pseudo-spectral operators without excessive damaging effects of round-off error. There are essentially three distinct approaches to computing derivatives with Chebyshev pseudospectral operators: One approach is to explicitly construct the matrix representation of the pseudospectral derivative operator and perform a matrix-vector multiplication. For small sizes of the matrix (i.e., order of the approximation) this straightforward approach can give good results and may even yield performance superior to that of the other approaches. Current codes, however, can require up to 500 Chebyshev modes. This number is likely to rise as the solutions of more complex problems are attempted. The other two approaches involve performing transformations between physical space and Chebyshev space. One "transform" approach is to apply an FFT and the other is to apply the Clenshaw recursion algorithm. In this paper, all three approaches are compared in terms of accuracy and are found to have different properties with respect to round-off error. In fact, the second-derivative approximation via matrix-vector multiplication may be accomplished in several ways. All these approaches are found to have different properties with respect to round-off error. However, in each case, the error is worst neat the boundaries. A "preconditioning" technique that attempts to damp the (worst) errors near the boundaries, first suggested by Breuer and Everson (1990) to be applied to the FFT approach, is extended for application to the other approaches and is found to substantially improve accuracy.
The Use of Coding Theory in Computational Complexity
Authors: J. Feigenbaum
Venue:  (1995)

The interplay of coding theory and computational complexity theory is a rich source of results and problems. We survey three of the major themes in this area: 1. the use of codes to improve algorithmic efficiency 2. the theory of program testing and correcting, which is a complexity theoretic analogue of error detection and correction 3. the use of codes to obtain characterizations of traditional complexity classes such as NP and PSPACE; these new characterizations are in turn used to show that certain combinatorial optimization problems are as hard to approximate closely as they are to solve exactly. This article is based on a talk given at the Short Course on Coding Theory at the American Mathematical Society meeting in San Francisco, CA in January, 1995. 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
Proposal of an Autonomous Group-Management Model and Its Application to Intelligent Transport System
Authors: Akitoshi Shimura, Toru Sakaibara, Masashi Hiraiwa, Takeiki Aizono
Venue: Proceedings of the The Sixth International Symposium on Autonomous Decentralized Systems (ISADS'03) (2003)

We propose an autonomous group-management model where each node autonomously judges whether to work with other nodes and dynamically forms a group to complete a requested job. This model was developed for mobile systems that consist of mobile terminals and base stations (BSs). The BSs are connected by a network, and each BS judges if it should form a group with other BSs based on their physical locations and the type of job without relying on direction from the other BSs. Therefore, each BS is "autonomous". The BSsdynamically form local groups without any centralized manager, share information, and complete a job, so this system is well suited to highly distributed systems where high performance is necessary.An intelligent transport system (ITS) is a typical application that matches this model. Various information is provided from BSs to moving cars in an ITS. Such a system will cover a wide area (all of Japan) and will include a huge number of BSs. High performance is required because many cars move at high-speed. Therefore, we have applied our proposed model to a smart gateway (SG) system ¿ one of the ITSs promoted by the Telecommunication Advancement Organization of Japan (TAO). We have developed a new type of BS according to this model and have installed a series of such BSs along roads for ourevaluation of the system.
Architecture, Design Methodology, and Component-Based Tools for a Real-Time Inspection System
Authors: John Albert Horst
Venue: Proceedings of the Third IEEE International Symposium on Object-Oriented Real-Time Distributed Computing (2000)

We describe a real-time, component-based system for an inspection application. We chose the inspection application and the accompanying task (or scenario) so that we might fully exercise and test our theories about real-time complex systems, system architectures, design methodologies, and software tools. We will describe the application, give a history and description of our system architecture and design methodology, describe the real-time software tools we used, and conclude with a discussion of real-time and object-oriented challenges solved.
Improving OLAP Performance by Multidimensional Hierarchical Clustering
Authors: Volker Markl, Frank Ramsak, Rudolf Bayer
Venue: Proceedings of the 1999 International Symposium on Database Engineering & Applications (1999)

Data-warehousing applications cope with enormous data sets in the range of Gigabytes and Terabytes. Queries usually either select a very small set of this data or perform aggregations on a fairly large data set. Materialized views storing pre-computed aggregates are used to efficiently process queries with aggregations. This approach increases resource requirements in disk space and slows down updates because of the view maintenance problem. Multidimensional hierarchical clustering (MHC) of OLAP data overcomes these problems while offering more flexibility for aggregation paths. Clustering is introduced as a way to speed up aggregation queries without additional storage cost for materialization. Performance and storage cost of our access method are investigated and compared to current query processing scenarios. In addition performance measurements on real world data for a typical star schema are presented.
I-Net+ Study Guide: Exam IKO-002, 2 edition
Authors: David Groth, Dorothy McGee
Venue:  (2002)

:Here's the book you need to prepare for CompTIA's i-Net+ Exam. This Sybex Study Guide provides: Full coverage of every exam objective Practical information on network hardware Hundreds of challenging review questions, in the book and on the CD Leading-edge exam preparation software, including a testing engine and electronic flashcards Authoritative coverage of all exam objectives, including: Internet Basics Web Site Development Performance Monitoring Networking Fundamentals Internet Security E-Business Concepts Featured on the CD The enclosed CD is packed with vital preparation tools and materials, beginning with the Sybex EdgeTest testing engine for the I-Net+ Exam. Loaded with hundreds of practice questions, it lets you test yourself chapter by chapter or according to objective areas. You'll also find electronic flashcards for your PC and Palm handhelds and two bonus exams that will help you prepare for the test. Also included is a fully searchable electronic copy of the book. About the Authors: David Groth, A+, Network+, Server+, MCT, CNA, and i-Net+, is President and Chief Geek of Practical Training Solutions, a global franchise system of training centers. He is the author of the best-selling A+ Complete Study Guide from Sybex, as well as the Network+ Study Guide. Dorothy L. McGee, i-Net+, is a computer professional with over 14 years experience in the industry.
Teach Yourself VISUALLY Restoration and Retouching with Photoshop Elements 2.0, 1 edition
Authors: Mike Wooldridge
Venue:  (2003)

:Are you a visual learner? Do you prefer instructions that show you how to do something -- and skip the long-winded explanations? If so, then this book is for you. Open it up and you'll find clear, step-by-step screen shots that show you how to tackle more than 100 Photoshop Elements 2 restoration and retouching tasks, from correcting color, repairing holes, and improving focus to printing or posting your restored images.
Independent component analysis approach to detect the cosmic microwave background radiation from satellite measurements
Authors: Emanuele Salerno
Venue:  (2000)

The source separation problem applied to the electromagnetic maps from the PLANCK satellite measurements is attacked here by means of an Independent Component Analysis (ICA) approach. This kind of techniques are totally blind with respect to the system to be identified, and only assume statistical independence of the signals to be separated. The computational scheme of our ICA implementation is described and compared with other existing separation strategies, and some results from simulated experiments are shown. TEL:: +39 050 3153137 EMAIL:: salerno@iei.pi.cnr.it
Time-stamped actions in $p$CRL algebras
Authors: Mark B. Zwaag
Venue:  (2000)

We present two extensions of \pcrl\ with time-stamped actions: \pcrlat\ for absolute time and \pcrlrt\ for relative time. We define timed bisimilarity for both versions and prove that the given axiomatisations are ground complete, provided that the data types have built-in equality and Skolem functions. We base the completeness proofs on the completeness results for untimed \pcrl.
Investigating the Maintenance Implications of the Replication of Code
Authors: Elizabeth Burd, Malcolm Munro
Venue: Proceedings of the International Conference on Software Maintenance (1997)

This paper describes an investigation into the use of code replication within legacy software systems. Two cases of replication are investigated. These are replication with an individual program and replication of an entire or part of a program across a program suite. For each of the cases an example is given from code used within the commercial sector. The instances of replication are then investigated and the implication of their occurrences within the code on the maintenance process are considered. The reasons why code replication is not a form of software reuse are discussed. Finally this paper investigates whether, with reengineering, areas of high usage of code replication are potential candidates for reuse.
A User Guide to HyTech
Authors: Thomas A. Henzinger, Pei Ho, Howard Wong-Toi
Venue:  (1995)

HyTech is a tool for the automated analysis of embedded systems. This document, designed for the first-time user of HyTech, guides the reader through the underlying system model, and through the input language for describing and analyzing systems. The guide gives several examples of usage, some hints for gaining maximal computational efficiency from the tool, and the complete grammar for the input language. The version of HyTech described in this guide was released in August 1995, and is available through anonymous ftp from ftp.cs.cornell.edu in the directory ~pub/tah/HyTech, and through the World-Wide Web via HyTech''s home page http://www.cs.cornell.edu/Info/People/tah/hytech.html
Dynamic Configuration Management in the Guide Object-Oriented Distributed System
Authors: Ibaa Oueichek, Xavier Rousset de Pina
Venue: Proceedings of the 3rd International Conference on Configurable Distributed Systems (1996)

The Configuration Management Service is the part of system management which provides support for dynamic reconfiguration that allows addition and removal of components without stopping the whole system. This paper presents an efficient algorithm for dynamic configuration management, which realizes a difficult compromise between four important criterion: correctness and system consistency, performance and global overhead of the system, support for a large class of applications which will survive system changes, and reducing the required mechanisms for algorithm implementation.
Protocols for Designing a Fast and Perfect Group-Oriented Secret Key Sharing in Distributed Systems
Venue: Proceedings of the 1996 International Symposium on Parallel Architectures, Algorithms and Networks (1996)

This paper presents a fast and perfect secret key sharing scheme based on a simple geometric method to solve group-oriented secret sharing problems in distributed systems. This scheme does not need the existence of the trusted authority and can reduce the needed time of sending messages to a group of receivers due to multiplication operations only. The scheme can be shown to be very secure, because it is not only a perfect secret sharing but also when the cryptanalyst tries to compute secret values, he must solve the simultaneous trigonometric equations with t-1 equations, where t is the threshold value in the secret key sharing scheme as presented in this paper and the number of unknown values are much more than the number of equations so that he will obtain no exact solution. Furthermore, it can dynamically insert or delete any participant in a group without affecting these original participants, and it is easy to change the shares without changing the original secret key.
A Solution for the Priority Queue Problem of Deadline-Ordered Service Disciplines
Authors: Norival R. Figueira
Venue: Proceedings of the 6th International Conference on Computer Communications and Networks (1997)

To provide service guarantees in packet-switching net-works, several deadline-ordered service disciplines have been proposed, including Delay-EDD, Jitter-EDD, Leave-in-Time, RFS, and Virtual-Clock. In a dead-line- ordered service discipline, packets are assigned transmission deadlines and are transmitted according to the deadline-ordered scheduling policy: transmit packets in increasing order of deadlines. Although these service disciplines provide desirable quality of service (QoS) guarantees, they have been regarded as unfeasible for high-speed networks due to the high overhead imposed by the sorting of packets in the server queue. This paper shows that these service disciplines become efficient if they replace the deadline-ordered scheduling policy with a new scheduling policy that is defined in this paper. This new scheduling policy uses hardware support to achieve an O(1) time complexity. We prove that a server that employs this new scheduling policy provides a delay bound to real-time packets that is slightly larger than what the server can provide with deadline-ordered scheduling.
On the Design of Optimization Criteria for Multiple Sequence Alignment
Authors: Dannie Durand, Martin Farach
Venue:  (1996)

Multiple sequence alignment (MSA) is important in functional, structural and evolutionary studies of sequence data. Much research has focussed on posing MSA as an optimization problem, and several optimization criteria have been explored. In this paper, we discuss biological and mathematical problems that arise in cost function design for the multiple sequence alignment problem. In particular, we focus on tree alignment, which is often viewed as the most ``biological'''' of the rigorous approaches to MSA. We point out several important pitfalls in current optimization approaches to MSA and identify characteristics for good cost function design. We address some extra design issues specific to approximation algorithms. We hope these ideas will lead to future research on a biologically realistic and mathematically rigorous approach to MSA.
Dynamics of Convection with Magnetic Fields
Authors: Steven R. Lantz
Venue:  (1991)

Supercomputer studies of convection with magnetic fields are motivated by observations of the Sun, where many of the magnetic phenomena visible at the surface are driven by fluid motions in the underlying solar convection zone. This paper describes the results from simulations of a particular model of magnetoconvection, based on the anelastic approximation of Gough [1] and Ogura and Charney [2], which has been extended by Ginet and Sudan [3] to include magnetic effects. The present work focuses on detailed dynamics at the level of a single convection cell, building on a code written by Ginet [4], who used it to study the zero-field limit. The magneto-anelastic equations are discretized [sic] on a 64 X 64 finite-difference grid and time-advanced using a predictor-corrector scheme; the method is stable for upward of 100,000 time steps, provided the diffusion parameters modeling subgrid effects are taken to be sufficiently large artificially so, when compared to solar values, though such diffusion can be thought of as crudely modeling the subgrid-scale turbulence. Simulations of the model conducted on the IBM 3090-600J supercomputer at the Cornell National Supercomputer Facility have revealed that convection can be significantly altered by magnetic fields, when magnetic flux is being fed in at the bottom boundary. The stabilizing influence of the fields leads to modification of the initially chaotic behavior, giving rise to a succession of new convection patterns as field strength is increased. Five distinct states of magnetoconvection have been found, representing various stages in a transition from tilted, unsteady convection with no magnetic fields, to steady counterrotating rolls, to total suppression of motion by magnetic tension. Video visualization, based on images produced on an IBM 5080 channel-attached workstation, has been crucial in identifying these regimes and in working out the mechanisms behind their dynamics; therefore, a sample video illustrating the new insights yielded by high-resoluatin color graphics is also being submitted with this paper demontrating that the IBM 3090 is most effective when it is teamed with an IBM graphics workstation.
Modeling Condensed-Phase Chemistry Through Molecular Dynamics Simulation
Authors: Srinivasan S. Iyengar, Christian J. Burnham, Matt K. Petersen, Gregory A. Voth
Venue: Computing in Science and Engineering (2003)

The challenges and problems involved in simulating condensed-phase dynamics, particularly for systems involving cleavage and formation of chemical bonds are substantial. The authors describe two methods for simulating protonated liquid water and condensed-phase reaction dynamics, in which the commonly used multi-atom empirical force fields are inadequate.
An Assessment of Gigabit Ethernet as Cluster Interconnect
Authors: Jens Mache
Venue: Proceedings of the 1st IEEE Computer Society International Workshop on Cluster Computing (1999)

With the advent of Gigabit Ethernet network technology, a new contender for the next-generation cluster interconnect is on the horizon. In this paper, we benchmark Gigabit Ethernet and compare it to other cluster interconnects, namely Fast Ethernet, Myrinet and Scalable Coherent Interface.For a meaningful comparison, benchmark experiments are carried out at two levels: TCP/IP networking and MPI parallel programming. Using high-end PCs (Pentium III 450 MHz) and standard system software (Linux and MPICH), our results show that with Gigabit Ethernet end-to-end throughputs of up to 44 MBytes per second can be achieved. A change from Fast Ethernet to Gigabit Ethernet resulted in performance gains of up to a factor of 5.05 for ftp, up to a factor of 3.10 for MPI point-to-point communication and up to a factor of 2.58 for some NAS parallel benchmarks, depending on communication granularity and message size. Further performance gains seem to require improved protocol processing and node hardware (memory bandwidth, file system, PCI bus).
Fix Your Own PC, 7 edition
Authors: Corey Sandler, Pinder Sandler
Venue:  (2002)

:With a good set of screwdrivers, an antistatic strap, and Fix Your Own PC, you'll be ready to tackle any job - big or small. Packed with detailed graphics and photos, this guide will quickly and easily help you diagnose and fix your own PC.
Performance Analysis of a CAN / CAN Bridge
Authors: H. Ekiz, A. Kutlu, M. D. Baba, E. T. Powner
Venue: Proceedings of the 1996 International Conference on Network Protocols (ICNP '96) (1996)

The Controller Area Network (CAN) is a serial bus with high speed, high reliability, and low cost for distributed real time control applications. The CAN is a desirable, cheap solution for networks in industrial environments, but there is limit on the maximum length of a single CAN bus. A solution is to divide the CAN network into segments and connect them using bridges. Bridges are high performance devices that are used to interconnect LANs at the Logical Link Control (LLC) or Medium Access Control (MAC) level in the protocol hierarchy. Unlike many serial communication protocols the CAN message contains no information relating to the destination and source addresses. Instead the message contains an identifier which indicates the type of information contained in the message. Because of this feature of the CAN message It is not possible to use traditional address based bridges to connect CAN segments. The aim of this study is not only to design and implement a bridge to connect CAN segments based on CAN protocol features but also to do performance analysis of the designed bridge. The designed bridge is a transparent bridge, and uses a learning process to built-up a forwarding database.
Red Hat RPM Guide
Authors: Chris Ricker, Chip Turner
Venue:  (2002)

:Reviewed and approved by the experts at Red Hat, this in-depth guide offers a complete education on Red Hat Package Manager, or RPM. Veteran software developer Eric Foster-Johnson supplies everything you need to know to create applications that rely on RPM, or to package and deploy software in RPM format. First, you will learn how the package management approach, along with specific RPM tools, enables more efficient user control. Then you'll move step by step through preparing software for release in an easy-to-manage RPM format, explore programming interfaces and supplemental software that can enhance RPM operation, and acquire the knowledge you need to extend RPM functionality. With its detailed coverage, comprehensive appendices, and handy at-a-glance references, this book is a resource you'll consult many times over.
Congestion Control Using Fuzzy Logic in Differentiated Services Networks
Authors: Runtong Zhang, Jian Ma
Venue: Proceedings of the Fourth International Conference on Computational Intelligence and Multimedia Applications (2001)

The basic objectives of future Internet are to increase the network capacity, to offer a practically differentiated services for traffic with different requirements such as real-time and non-real-time services.These objectives introduce very strict requirements for traffic control systems and lead to the establishment of Differentiated Services (DS) concept. However, the new features of DS networks, where several classes of precedence are allowed, lead the inefficiency of the congestion control approaches for the existed best-effort Internet.In this paper, a new congestion control approach using fuzzy logic in the DS domain is presented.Simulation shows that the approach is efficient and promising.