ppxscal/embedding_network huggingface dataset:
Block LU Preconditioners for Symmetric and Nonsymmetric Saddle Point Problems
Authors: Leigh Little, Yousef Saad, Laurent Smoch
Venue: SIAM Journal on Scientific Computing (2003)

In this paper, a general-purpose block LU preconditioner for saddle point problems is presented. The main difference between the approach presented here and that of other studies is that an explicit, accurate approximation of the Schur complement matrix is efficiently computed. This is used to compute a preconditioner to the Schur complement matrix, which in turn defines a preconditioner for the global system. A number of different variants are developed and results are reported for a few linear systems arising from CFD applications.
An Effective Collision Resolution Mechanism for Wireless LAN
Authors: Chonggang Wang, Bin Li, Bo Li, Kazem Sohraby
Venue: Proceedings of the 2003 International Conference on Computer Networks and Mobile Computing (2003)

Based on the current standardized IEEE 802.11 distributed coordination function (DCF) protocol, this paper proposes a new efficient collision resolution mechanism, called GDCF. Our main motivation is based on the observation that 802.11 DCF decreases the contention window to the initial value after each success transmission, which essentially assumes that each successful transmission is an indication that the system is under low traffic loading. GDCF takes a more conservative measure by halving the contention window size after c consecutive successful transmissions. This "gentle" decrease lowers the collision probability,especially when the competing node number is large. We compute the optimal value for c, and the numerical results from both analysis and simulation demonstrate that GDCF significantly improve the performance of 802.11 DCF including throughput, fairness, and energy efficiency. In addition, GDCF is flexible for supporting priority access by selecting different values of c for different traffic types; it is fully compatible with the original 802.11 DCF, and simple to implement, as it does not requires changes in control message structure andaccess procedures in DCF.
Design and design centers in engineering education
Authors: Clive L. Dym
Venue: Artificial Intelligence for Engineering Design, Analysis and Manufacturing (1998)

This paper is intended to be the opening salvo of the workshop, Computing Futures in Engineering Design (Dym, 1997). Thus, I want to take this privileged moment to ask you to think with me about the role of design in engineering. In particular, I want to reflect upon how design is articulated and how design is taught; about the role of design in engineering education and in the practice of engineering; and about the role that could be played locally and, perhaps, nationally by a center devoted to design education. Because I teach here at Harvey Mudd College (HMC), and because most of you are visitors, I will place my remarks in our context by telling you about what we do here and how that doing has shaped my thinking.
Multitaper techniques and filter diagonalisation - a comparison
Authors: T. Levitina, E. Brändas
Venue: Proceedings of the international conference on Computational methods in sciences and engineering (2003)

In the present contribution we compare the new Multitaper Filtering technique with the very popular Filter Diagonalisation Method. The substitution of a time-independent problem, like the standard Schrödinger equation, by a time dependent one from the Filter Diagonalisation Method allows the employment of and comparison with standard signal processing filtration machinery. The use of zero order prolate spheroidal tapers as filtering functions is here extended and exactly formulated using techniques originating from general investigations of prolate spheriodal wave functions. We investigate the modifications presented with respect to accuracy and general effectiveness. The approach may be useful in various branches of physics and engineering sciences including signal processing applications as well as possibly also in general time dependent processes.
When 2 + 2 = 5
Authors: Aaron Weiss
Venue: netWorker (2003)

It used to be easy to know when someone's ripping you off. If at four o'clock in the morning some guy with an Australian accent is on your TV shouting out the merits of a telescoping mop, there are many good reasons not to buy it. But when you're browsing the aisles at your local ElectronicStuffWarehouse it becomes a whole lot harder to tell. And I'm not even talking about all those "rebates."
Electro-Optic E-field Sensor Using an Optical Modulator
Authors: I. Zaldívar-Huerta, J. Rodríguez-Asomoza
Venue: Proceedings of the 14th International Conference on Electronics, Communications and Computers (2004)

An electric field sensor array using optical coherencemodulation of light is proposed here. The system consistsof lithium niobate (LiNbO3) optical coherence modulatoracting as electric field sensor. The main characteristics ofcoherence-modulated transmissions include the need ofusing broad-band optical sources and integrated opticslithium niobate electro-optic retarders. Coherence-modulatedsystems have been studied for the last fewyears as new potential high-speed optical links useful forpoint-to-point, local area networks, and bi-directionaltransmissions, at optical wavelengths around 1300 nm.This paper describes the experimental system andcharacterization of the electro-optic sensor for detectionof sinusoidal electric field.
Organizational level e-business resource allocations: an analytical approach to implementation
Authors: Adel Omar Alameri
Venue:  (2003)

Despite the newness of conducting business on the Internet, Electronic Business (E-Business) is growing at an unprecedented rate. Experts predict that E-business will continue to expand as more people get connected to the Internet and as a result, they become potential online consumers. Companies and entrepreneurs, on the other end, are rushing to have a share of the e-market by launching their web sites. However, many studies show that failures do occur in E-Business. A large number of E-Business companies, especially e-tailing ones, began failing. (startupfailure.com) Reasons behind these failures include lack of strategic implementation planning, incorrect or unclear picture of E-business and its models and environment, and inefficient management practices. All these reasons have led to the failure of recognizing the important role of e-customers. Therefore, customers' input is not considered or if it is considered, it is not integrated in the implementation process as early as it should be. This study provides a framework, that is based on sound system engineering principles and optimization techniques, for implementing E-Business. A systematic 3-step way is developed to solve the resource allocation problem. First, the status quo of the business is examined. Next, resource needs of the businesses are determined. Last, models are developed to optimize needed resources. Data are collected from e-customers, information technology professionals, and companies' managers (through surveys, interviews, and clickstream data). In order to determine the critical factors of a successful E-Business and weigh their importance, the data will be tested statistically. Then, Analytical Hierarchy Process, which a multi criteria decision technique, is utilized to rank variables according to their importance. Finally, Quality Function Deployment (QFD) is applied to optimize resources in order to maximize the success of the E-business.
A ground-truthing engine for proofsetting, publishing, re-purposing and quality assurance
Authors: Steven J. Simske, Margaret Sturgill
Venue: Proceedings of the 2003 ACM symposium on Document engineering (2003)

We present design strategies, implementation preferences and throughput results obtained in deploying a UI-based ground truthing engine as the last step in the quality assurance (QA) for the conversion of a large out-of-print book collection into digital form. A series of automated QA steps were first performed on the document. Five distinct zoning analysis options were deployed and the PDF output thence generated was used to regenerate TIFF files for comparison to the originals. Regenerated TIFFs failing automated QA or a separate visual QA were tagged for ground truthing. Less than 3% of the pages in a 1.2x106-page corpus required ground truthing, resulting in a throughput rate of "fully-proofed" pages of 2x105 pages/man-week. Among the design advantages crucial for this throughput rate was the use of the identical zoning engine for the original production workflow and for the ground truthing engine.
Non-linear anisotropic elasticity for real-time surgery simulation
Authors: Guillaume Picinbono, Hervé Delingette, Nicholas Ayache
Venue: Graphical Models (2003)

In this paper, we describe the latest developments of the minimally invasive hepatic surgery simulator prototype developed at INRIA. A key problem with such a simulator is the physical modeling of soft tissues. We propose a new deformable model based on non-linear elasticity, anisotropic behavior, and the finite element method. This model is valid for large displacements, which means in particular that it is invariant with respect to rotations. This property improves the realism of the deformations and solves the problems related to the shortcomings of linear elasticity, which is only valid for small displacements. We also address the problem of volume variations by adding to our model incompressibility constraints. Finally, we demonstrate the relevance of this approach for the real-time simulation of laparoscopic surgical gestures on the liver.
Estimating the Joint Spectral Radius of a Nonseparable Multiwavelet
Authors: Ana M. C. Ruedin
Venue: Proceedings of the XXIII International Conference of the Chilean Computer Science Society (2003)

The joint spectral radius ¿ of 2 matrices is related to theboundedness of all their products. Calculating ¿ is known tobe NP-hard. In this work we estimate the joint spectral radiusassociated to a bidimensional separable multiwavelet,in order to analyze its Hölder continuity. To the author'sknowledge this has not been done. The analysis aims at testingthe aplicability of the multiwavelet transform to thoseaspects of image processing where continuous basis functionsperform best, such as image synthesis, image magnificationand image compression. We adapt an algorithm dueto Heil and Colella, that works for unidimensional wavelets,to our more complex setting, to prove that ¿
Breeding Software Test Cases for Complex Systems
Authors: A. Watkins, D. Berndt, K. Aebischer, J. Fisher, L. Johnson
Venue: Proceedings of the Proceedings of the 37th Annual Hawaii International Conference on System Sciences (HICSS'04) - Track 9 - Volume 9 (2004)

The potential cost savings from handling software errors within a development cycle, rather than subsequent cycles, has been estimated at 38.3 billion dollars. Such figures emphasize that current testing methods are inadequate, and that helping reduce software bugs and errors is an important area of research with a substantial payoff. This paper reports on research using genetic algorithms for test case generation for systems level testing, building on past work at the unit testing level. The goals of the paper are to explore the use of genetic algorithms for testing complex distributed systems, as well as to develop a framework or vocabulary of important environmental attributes that characterize complex systems failures. In addition, preliminary visualization techniques that might help software developers to understand and uncover complex systems failures are explored.
Two-level hierarchy with sparsely and temporally coded patterns and its possible functional role in information processing
Authors: Masaki Nomura, Toshio Aoyagi, Masato Okada
Venue: Neural Networks (2003)

We study the stability of two types of mixed states in an oscillator neural network model. Patterns to be stored are represented by complex variables whose amplitudes are either 0 (silent state) or 1 (firing state) and whose phases represent the timing of firing. The mixed states are defined in terms of a certain type of average over some specified number s of memory patterns. We define two types of such mixed states, each of which corresponds to a different type of restriction placed on this set of s memory patterns. The stability of each type is investigated both theoretically and numerically. We find that only one type of a mixed state, which consists of temporally correlated patterns, is stable. Finally, we discuss a possible functional role of such mixed states in information processing.
Design and implementation of a portable and adaptable load balancing framework
Authors: Erik Putrycz
Venue: Proceedings of the 2003 conference of the Centre for Advanced Studies on Collaborative research (2003)

Scaling applications to large networks and an increasing number of users has been since years a technical challenge. Today, well known technologies exist to scale applications to local networks but scaling to large networks with high latency is still a challenge. Load balancing at the middleware level allows more flexibility (in terms of granularity and distribution) than existing solutions based at lower system levels. However, it requires an execution infrastructure and mechanisms to be integrated seamlessly.DLBS (Dynamic Load Balancing Service) brings new solutions regarding large scale load balancing for middleware-based applications. DLBS offers a multi-criteria and easily customizable load balancing service. It consists of a scalable monitoring infrastructure, a connection manager (integrated into the middleware) and customizable load balancing strategies.In order to stay efficient, implementation of a low level service requires a low overhead. DLBS aims to be a generic load balancing service. Easy and efficient portability with a CORBA Object Request Broker has been possible thanks to aspect-oriented programming.
Enhancing Reliability of Operational Interconnections in FPGAs
Authors: Alex Fit-Florea, Miroslav Halas, Fatih Kocan
Venue: Proceedings of the conference on Design, automation and test in Europe - Volume 1 (2004)

SRAM-based Field-Programmable Gate Arrays (FPGAs) have fixed numbers of wires, switches and look-up tables. An application does not fully utilize all available components in a FPGA, e.g. wires. In this paper, we propose methods to improve reliability of less reliable operational interconnections by efficiently utilizing unused wires to mask errors dynamically. With these methods, we are able to improve the reliability of more than two-thirds of all interconnections in the studied MCNC benchmarks. As a result, the overall unreliability of operational interconnections decreases more than 20%.
Authority Models for Collaborative Authoring
Venue: Proceedings of the Proceedings of the 37th Annual Hawaii International Conference on System Sciences (HICSS'04) - Track 1 - Volume 1 (2004)

We define an authority model, in the context of CSCW, as the characteristics of the system that determine who has control over objects in the system, and how this control manifests. In this paper we present two natural authority models (free-form and owner-centric) and, employing an empirical study, explore the question "which authority model is best for collaborative, commons-based content authoring?" We discover that the answer varies, depending on whether productivity or user satisfaction is to be the metric of goodness, and likely can not be phrased in absolutes.
A comprehensive three-dimensional model of the cochlea
Authors: Edward Givelberg, Julian Bunn
Venue: Journal of Computational Physics (2003)

The human cochlea is a remarkable device, able to discern extremely small amplitude sound pressure waves, and discriminate between very close frequencies. Simulation of the cochlea is computationally challenging due to its complex geometry, intricate construction and small physical size. We have developed, and are continuing to refine, a detailed three-dimensional computational model based on an accurate cochlear geometry obtained from physical measurements. In the model, the immersed boundary method is used to calculate the fluid-structure interactions produced in response to incoming sound waves. The model includes a detailed and realistic description of the various elastic structures present. In this paper, we describe the computational model and its performance on the latest generation of shared memory servers from Hewlett Packard. Using compiler generated threads and OpenMP directives, we have achieved a high degree of parallelism in the executable, which has made possible several large scale numerical simulation experiments that study the interesting features of the cochlear system. We show several results from these simulations, reproducing some of the basic known characteristics of cochlear mechanics.
Applying Database Support for Large Scale Data Driven Science in Distributed Environments
Authors: Sivaramakrishnan Narayanan, Umit Catalyurek, Tahsin Kurc, Xi Zhang, Joel Saltz
Venue: Proceedings of the 4th International Workshop on Grid Computing (2003)

There is a rapidly growing set of applications, referredto as data driven applications, in which analysis of largeamounts of data drives the next steps taken by the scientist,e.g., running new simulations, doing additional measurements,extending the analysis to larger data collections.Critical steps in data analysis are to extract the data of interestfrom large and potentially distributed datasets andto move it from storage clusters to compute clusters forprocessing. We have developed a middleware framework,called GridDB-Lite, that is designed to efficiently supportthese two steps. In this paper, we describe the applicationof GridDB-Lite in large scale oil reservoir simulation studiesand experimentally evaluate several optimizations thatcan be employed in the GridDB-Lite runtime system.
Protection in flexible operating system architectures
Authors: Christophe Rippert
Venue: ACM SIGOPS Operating Systems Review (2003)

This paper presents our work concerning flexibility and protection in operating system kernels. In most existing operating systems, security is enforced at the price of flexibility by imposing protection models on the system programmer when building his system. We prove that flexibility can be preserved by separating the management of the protection policy from the tools used to enforce it. We present the secure software framework we have implemented in the THINK architecture to manage protection policies and guarantee they are carried out as specified. We then detail the elementary protection tools provided to the programmer so he can protect his system against unauthorized accesses and denial of service attacks. These tools are implemented in a policy-neutral way so as to guarantee their flexibility. Finally we validate our results by evaluating the flexibility of the protection provided on selected examples of dynamic modification of the protection policy.
A scalable method for treating bottlenecks in a dynamically controlled DiffServ environment
Authors: Markus Albrecht, Matthias Frank, Rolf Göpffarth
Venue: Proceedings of the 28th Annual IEEE International Conference on Local Computer Networks (2003)

Differentiated Services provide a scalable Quality ofService Concept for the Internet. It allows differentiatingservice classes which may be treated individually. Thedata arising between two neighboring network providersis regulated by Service Level Agreements (SLA). The useof static SLAs lacks flexibility. With the introduction ofBandwidth Brokers a concept was provided enabling adynamic Differentiated Services environment. BandwidthBrokers automatically negotiate and set up SLAs.However, this may still fail if there are bottlenecks in thenetwork that may lead to congestion. This paper extendsan existing scalable Bandwidth Broker concept forhandling congestion in dynamic Differentiated Servicesnetworks. Our mechanism applies in contrast to anyprevious approach a dynamic overprovisioning and isable to handle different levels of congestion situations.With help of this dynamic overprovisioning we are able tomaximize the utilization. The merits of this new conceptare shown in simulation.
Heredity of the index of convergence of the line digraph
Authors: Weigen Yan, Fuji Zhang
Venue: Discrete Applied Mathematics (2003)

Let D be a digraph, and let Ln(D) and k(D) denote the nth iterated line digraph of D and the index of convergence of D, respectively. We prove that if D contains neither sources nor sinks, then: (1) k(Ln(D))=k(D)=0 if every connected component of D is a directed cycle. (2) k(Ln(D))=k(D)+n if there exists at least one connected component of D that is not a directed cycle. Finally, we prove that if D has no sources or no sinks then k(D) ≤ k(L(D)) ≤ k(D)+1.
Evaluating Scheduling and Replica Optimisation Strategies in OptorSim
Authors: David G. Cameron, Rubén Carvajal-Schiaffino, A. Paul Millar, Caitriana Nicholson, Kurt Stockinger, Floriano Zini
Venue: Proceedings of the 4th International Workshop on Grid Computing (2003)

Grid computing is fast emerging as the solution to theproblems posed by the massive computational and datahandling requirements of many current international scientificprojects. Simulation of the Grid environment is importantto evaluate the impact of potential data handlingstrategies before being deployed on the Grid. In this paper,we look at the effects of various job scheduling and datareplication strategies and compare them in a variety of Gridscenarios, evaluating several performance metrics. We usethe Grid simulator OptorSim, and base our simulations ona world-wide Grid testbed for data intensive high energyphysics experiments.Our results show that the choice of scheduling and datareplication strategies can have a large effect on both jobthroughput and the overall consumption of Grid resources.
Handling variant requirements in domain modeling
Authors: Stan Jarzabek, Wai Chun Ong, Hongyu Zhang
Venue: Journal of Systems and Software (2003)

Domain models describe common and variant requirements for a family of similar systems. Although most of the notations, such as UML, are meant for modeling a single system, they can be extended to model variants. We have done that and applied such extended notations in our projects. We soon found that our models with variants were becoming overly complicated, undermining the major role of domain analysis which is understanding. One variant was often reflected in many models and any given model was affected by many variants. The number of possible variant combinations was growing rapidly and mutual dependencies among variants even further complicated the domain model. We realized that our purely descriptive domain model was only useful for small examples but it did not scale up. In this paper, we describe a modeling method and a Flexible Variant Configuration tool (FVC for short) that alleviate the above mentioned problems. In our approach, we start by modeling so-called domain defaults, i.e., requirements that characterize a typical system in a domain. Then, we describe variants as deltas in respect to domain defaults. The FVC interprets variants to produce customized domain model views for a system that meets specific requirements. We implemented the above concepts using commercial tools Netron FusionTM and Rational RoseTM. In the paper, we illustrate our domain modeling method and tool with examples from the Facility Reservation System domain.