ppxscal/embedding_network huggingface dataset:
A Chip for an Implantable Neural Stimulator
Authors: Gunnar Gudnason, Erik Bruun, Morten Haugland
Venue: Analog Integrated Circuits and Signal Processing (2000)

This paper describes a chip for a multichannel neural stimulator for functional electrical stimulation (FES). The purpose of FES is to restore muscular control in disabled patients. The chip performs all the signal processing required in an implanted neural stimulator. The power and digital data transmission to the stimulator passes through a 5 MHz inductive link. From the signals transmitted to the stimulator, the chip is able to generate charge-balanced current pulses with a controllable length up to 256 &mu;s and an amplitude up to 2 mA, for stimulation of nerve fibers. The quiescent current consumption of the chip is approx. 650 &mu;A at supply voltages of 6&ndash;12 V, and its size is 3.9&times;3.5 mm^2. It has 4 output channels for use in a multipolar cuff electrode.
Distributed algorithms visualisation for educational purposes
Authors: Boris Koldehofe, Marina Papatriantafilou, Philippas Tsigas
Venue: Proceedings of the 4th annual SIGCSE/SIGCUE ITiCSE conference on Innovation and technology in computer science education (1999)

We present our work on building interactive continuous visualisations of distributed algorithms for educational purposes. The animations are comprised by a set of visualisation windows. The visualisation windows are designed so that they demonstrate i) the different behaviours of the algorithms while running in different systems, ii) the different behaviours that the algorithms exhibit under different timing and workload of the system iii) the time and space complexities of the algorithms and iv) the "key ideas" of the functionality of the algorithms. Visualisations have been written for a set of lO algorithms that are tought in a Distributed Algorithms advanced undergraduate course.
Mixed Upwinding Covolume Methods on Rectangular Grids for Convection-Diffusion Problems
Authors: So-Hsiang Chou, Do Y. Kwak, Panayot S. Vassilevski
Venue: SIAM Journal on Scientific Computing (1999)

We consider an upwinding covolume or control-volume method for a system of first order PDEs resulting from the mixed formulation of a convection-diffusion equation with a variable anisotropic diffusion tensor. The system can be used to model the steady state of the transport of a contaminant carried by a flow. We use the lowest order Raviart--Thomas space and show that the concentration and concentration flux both converge at one-half order provided that the exact flux is in $H^1(\Omega)^2$ and the exact concentration is in $H^1(\Omega)$. Some numerical experiments illustrating the error behavior of the scheme are provided.
Two-stage multiple-comparison procedures for steady-state simulations
Authors: Halim Damerdji, Marvin K. Nakayama
Venue: ACM Transactions on Modeling and Computer Simulation (TOMACS) (1999)

Procedures for multiple comparisons with the best are investigated in the context of steady-state simulation, whereby a number k of different systems (stochastic processes) are compared based upon their (asymptotic) means &mgr;i (i = 1,2,&hellip;, k). The variances of these (asymptotically stationary) processes are assumed to be unknown and possibly unequal. We consider the problem of constructing simultaneous confidence intervals for mi-max j&ne;imj i=1,2,&ldots;,k which is known as multiple comparisons with the best (MCB). Our intervals are constrained to contain 0, and so are called constrained MCB intervals. In particular, two-stage procedures for construction of absolute- and relative-width confidence intervals are presented. Their validity is addressed by showing that the confidence intervals cover the parameters with probability of at least some user-specified threshold value, as the confidence intervals' width parameter shrinks to 0. The general assumption about the processes is that they satisfy a functional central limit theorem. The simulation output analysis procedures are based on the method of standardized time series (the batch means method is a special case). The techniques developed here extend to other multiple-comparison procedures such as unconstrained MCB, multiple comparisons with a control, and all-pairwise comparisons. Although simulation is the context in this paper, the results naturally apply to (asymptotically) stationary time series.
Numerical Implementation of a Space-Transformation Approach for Solving the Three-Dimensional Flow Equation
Authors: Dionissios T. Hristopulos, George Christakos, Marc Serre
Venue: SIAM Journal on Scientific Computing (1998)

This work is concerned with the numerical implementation of the space-transformation approach in porous media modeling. Space transformation is a mathematical approach that simplifies the study of multidimensional problems by reducing them to unidimensional ones. In particular, the implementation aspects considered in this work include (i) the development and testing of numerical space-transformation algorithms for three-dimensional, space-dependent functions that can be used to model flow within porous media, and (ii) the use of these algorithms to solve partial differential equations governing groundwater flow. We also establish the competitiveness of the space-transformation-based numerical procedures in terms of accuracy and speed. Further improvements in computational speed can be accomplished by parallel implementation of the space-transformation calculations. The space-transformation method is shown to provide a computationally efficient approach for obtaining three-dimensional flow solutions that honor the boundary conditions. This approach can be also used in stochastic flow modeling to generate multiple realizations of the random hydraulic head field.
The Geometry of Algorithms with Orthogonality Constraints
Authors: Alan Edelman, Tomás A. Arias, Steven T. Smith
Venue: SIAM Journal on Matrix Analysis and Applications (1999)

In this paper we develop new Newton and conjugate gradient algorithms on the Grassmann and Stiefel manifolds. These manifolds represent the constraints that arise in such areas as the symmetric eigenvalue problem, nonlinear eigenvalue problems, electronic structures computations, and signal processing. In addition to the new algorithms, we show how the geometrical framework gives penetrating new insights allowing us to create, understand, and compare algorithms. The theory proposed here provides a taxonomy for numerical linear algebra algorithms that provide a top level mathematical view of previously unrelated algorithms. It is our hope that developers of new algorithms and perturbation theories will benefit from the theory, methods, and examples in this paper.
Regularity of the Minimum Time Function and Minimum Energy Problems: The Linear Case
Authors: Fausto Gozzi, Paola Loreti
Venue: SIAM Journal on Control and Optimization (1999)

We prove new results on the continuity properties and on reachable sets of the minimum time function associated with a linear dynamical system in a separable Hilbert space H. Part of the results are new also in the finite dimensional case. The regularity results are stated thanks to the result we obtain on the connection between the minimum time function and the minimum energy.
Allocation Techniques for Reducing BIST Area Overhead ofData Paths
Authors: Ishwar Parulkar, Sandeep K. Gupta, Melvin A. Breuer
Venue: Journal of Electronic Testing: Theory and Applications (1998)

Built-in self-test (BIST) techniques modify functional hardware so that a chip has the capability to test itself. A prime concern in using BIST is the area overhead due to the modification of normal registers to BIST registers. This paper proposes register and interconnect assignment techniques that address the BIST area overhead issue during high-level synthesis. A minimal intrusion BIST methodology is employed where a subset of the functional registers are modified to be BIST registers. Depending on the BIST functions performed (test pattern generation and/or test response compression) and the concurrency of the functions, four types of BIST registers with varying costs are used. Data path allocation techniques are presented that (1) maximize the sharing of BIST registers between modules, and (2) minimize the number of expensive BIST registers that are essential for minimal intrusion BIST of a data path. The designs synthesized by our techniques have the same number of functional modules and registers as those synthesized using traditional approaches but require significantly lower BIST area overhead.
A compiler method for the parallel execution of irregular reductions in scalable shared memory multiprocessors
Authors: E. Gutiérrez, O. Plata, E. L. Zapata
Venue: Proceedings of the 14th international conference on Supercomputing (2000)

This paper presents a new parallelization method for reductions of arrays with subscripted subscripts on scalable shared memory multiprocessors. The mapping of computations is based on grouping reduction loop iterations into sets that are further assigned to the cooperating threads of computation. Iterations belonging to the same set are chosen in such a way that update different entries in the reduction array. That is, the loop distribution implies a conflict-free write distribution of the reduction array. The iteration sets are set up by building a loop-index prefetching data structure that allows to reorder properly the loop iterations. The proposed method is general, scalable, and easy to implement on a compiler. In addition it deals in a uniform way with one and multiple subscript arrays. In case of multiple indirection arrays, writes on the reduction array affecting different sets are solved by defining conflict-free supersets. A performance evaluation is presented. From the experimental results and performance analysis, the proposed method appears as a clear alternative to the array expansion and privatized buffer techniques, used on state-of-the-art parallelizing compilers, like Polaris or SUIF. The scalability problem that those techniques exhibit is missing in our method, as the memory overhead presented does not depend on the number of processors.
Payoff adaptation of communication for distributed interactive applications
Authors: Robin Kravets, Ken Calvert, Karsten Schwan
Venue: Journal of High Speed Networks (1998)

Present distributed applications are not typically designed to adapt to changes in network conditions. In addition, network-based adaptation does not typically consider the requirements of specific applications and, therefore, may take actions contradictory to applications needs. This paper presents a cooperative solution in which a configurable communication layer is used to adapt communication in response to both application requirements and network resource availability. Adaptation decisions are based on (1) payoff functions which capture the application requirements in a functional form, and (2) service availability curves which represent network resource availability. Experimentation with multimedia applications and a variable reliability protocol demonstrates the benefit of using payoff-based adaptation.
Real-Time Dependable Channels: Customizing QoS Attributes for Distributed Systems
Authors: Matti A. Hiltunen, Richard D. Schlichting, Xiaonan Han, Melvin M. Cardozo, Rajsekhar Das
Venue: IEEE Transactions on Parallel and Distributed Systems (1999)

Communication services that provide enhanced Quality of Service (QoS) guarantees related to dependability and real time are important for many applications in distributed systems. This paper presents real-time dependable (RTD) channels, a communication-oriented abstraction that can be configured to meet the QoS requirements of a variety of distributed applications. This customization ability is based on using CactusRT, a system that supports the construction of middleware services out of software modules called micro-protocols. Each micro-protocol implements a different semantic property or property variant and interacts with other micro-protocols using an event-driven model supported by the CactusRT runtime system. In addition to RTD channels, CactusRT and its implementation are described. This prototype executes on a cluster of Pentium PCs running the OpenGroup/RI MK 7.3 Mach real-time operating system and CORDS, a system for building network protocols based on the x-kernel.
Readability formulas in the new millennium: what's the use?
Authors: Karen A. Schriver
Venue: ACM Journal of Computer Documentation (JCD) (2000)

While readability formulas were intended as a quick benchmark for indexing readabilty, they are inherently unreliable: they depend on criterion (calibration) passages too short to reflect cohesiveness, too varied to support between-formula comparisons, and too text-oriented to account for the effects of lists, enumerated sequences,and tables on text comprehension. But readability formulas did spark decades of research on what comprehension really involoves.
Solving Stochastic Linear Programs with Restricted RecourseUsing Interior Point Methods
Authors: Patrizia Beraldi, Roberto Musmanno, Chefi Triki
Venue: Computational Optimization and Applications (2000)

In this paper we present a specialized matrix factorization procedure for computing the dual step in a primal-dual path-following interior point algorithm for solving two-stage stochastic linear programs with restricted recourse. The algorithm, based on the Birge-Qi factorization technique, takes advantage of both the dual block-angular structure of the constraint matrix and of the special structure of the second-stage matrices involved in the model. Extensive computational experiments on a set of test problems have been conducted in order to evaluate the performance of the developed code. The results are very promising, showing that the code is competitive with state-of-the-art optimizers.
A Web site to promote CS education as a research area
Authors: Vicki L. Almstrum
Venue: ACM SIGCSE Bulletin (1998)

This paper introduces a Web site designed as a tool for anyone wanting to carry out research in the area of CS education. The paper describes the motivation behind the various parts of the site and invites participation from the SIGCSE community in using the site and helping it evolve. The Web site highlights many possibilities for solid educational research and thus publicizes the field as a legitimate academic endeavor.
Multigrid for the Mortar Finite Element Method
Authors: Jayadeep Gopalakrishnan
Venue: SIAM Journal on Numerical Analysis (2000)

A multigrid technique for uniformly preconditioning linear systems arising from a mortar finite element discretization of second order elliptic boundary value problems is described and analyzed. These problems are posed on domains partitioned into subdomains, each of which is independently triangulated in a multilevel fashion. The multilevel mortar finite element spaces based on such triangulations (which need not align across subdomain interfaces) are in general not nested. Suitable grid transfer operators and smoothers are developed which lead to a variable V-cycle preconditioner resulting in a uniformly preconditioned algebraic system. Computational results illustrating the theory are also presented.
An agent oriented business model for e-commerce based on the NYSE specialist system
Authors: Kenneth Griggs
Venue: Proceedings of the 2000 ACM SIGCPR conference on Computer personnel research (2000)

The rapid development of commerce on the World Wide Web has been accompanied by the creation of new business models and customer relationships involving the use of intelligent software agents. Agents are characterized by autonomy, perception, and intelligence and have been used primarily for search and data mining activities on the Web. A parallel trend in electronic commerce is the development of auction markets in contrast to traditional fixed posted price models. Web based auction markets are structured on the &ldquo;English Auction&rdquo; model where a reserve price is established and bids are increased until the market is cleared. This paper describes an intelligent agent based architecture for electronic commerce. The proposed architecture implements a continuous double auction modeled on the two hundred-year-old New York Stock Exchange specialist system. The complex functionality of the specialist system is replicated through dedicated agents and knowledge bases that interact with buyer and seller agents. The specialist system, thought to be superior to other auction systems, requires a relatively high level of intelligence. The proposed architecture fully models the duties of a human specialist at a NYSE stock exchange post. These duties are broadly described as customer agent, principal, market catalyst, and auctioneer. In addition to describing the architecture, the paper includes a discussion of current research in electronic commerce auction markets and likely future impacts of the technology.
A hybrid channel allocation method for wireless communication networks
Authors: Anna Hać, Zhengping Chen
Venue: International Journal of Network Management (2000)

In this paper a new hybrid channel allocation method is presented, which focuses on both nominal and dynamic channel allocation. Copyright &copy; 2000 John Wiley Sons, Ltd.
Visualizing Evaluation in Scheme
Authors: Sho-Huan Simon Tung
Venue: Lisp and Symbolic Computation (1998)

RainbowScheme is a visual stepping system that presents Scheme program&lsquo;s run-time state using icons, colored environment trees, and colored Scheme code. A Scheme program can be executed step-by-step in RainbowScheme using a set of visual transformation rules called visualcode. Being able to visualize intermediate steps of a running program makes each individual step and the entire execution process easier to comprehend. In addition to describing visualcode with examples, this article presents RainbowScheme&lsquo;s user interface, implementation techniques, and evaluation results of using it in introductory programming courses.
Numerical Experience with a Reduced Hessian Methodfor Large Scale Constrained Optimization
Authors: Lorenz T. Biegler, Jorge Nocedal, Claudia Schmid, David Ternet
Venue: Computational Optimization and Applications (2000)

The reduced Hessian SQP algorithm presented in Biegler et al. [SIAM J. Optimization, Vol. 5, no. 2, pp. 314&ndash;347, 1995.] is developed in this paper into a practical method for large-scale optimization. The novelty of the algorithm lies in the incorporation of a correction vector that approximates the cross term Z^TWY_p. This improves the stability and robustness of the algorithm without increasing its computational cost. The paper studies how to implement the algorithm efficiently, and presents a set of tests illustrating its numerical performance. An analytic example, showing the benefits of the correction term, is also presented.
How to Build Robust Shared Control Systems
Authors: Ross Anderson, Cunsheng Ding, Tor Helleseth Torleiv Klove
Venue: Designs, Codes and Cryptography (1998)

Previous researchers have designed shared control schemes with a view to minimising the likelihood that participants will conspire to perform an unauthorised act. But, human nature being what it is, systems inevitably fail; so shared control schemes should also be designed so that the police can identify conspirators after the fact. This requirement leads us to search for schemes with sparse access structures. We show how this can be done using ideas from coding theory. In particular, secret sharing schemes based on geometric codes whose dual [n,k,d] codes have d andn as their only nonzero weights are suitable. We determine their access structures and analyse their properties. We have found almost all of them, and established some relations among codes, designs and secret-sharing schemes.
Surfels: surface elements as rendering primitives
Authors: Hanspeter Pfister, Matthias Zwicker, Jeroen van Baar, Markus Gross
Venue: Proceedings of the 27th annual conference on Computer graphics and interactive techniques (2000)

Surface elements (surfels) are a powerful paradigm to efficiently render complex geometric objects at interactive frame rates. Unlike classical surface discretizations, i.e., triangles or quadrilateral meshes, surfels are point primitives without explicit connectivity. Surfel attributes comprise depth, texture color, normal, and others. As a pre-process, an octree-based surfel representation of a geometric object is computed. During sampling, surfel positions and normals are optionally perturbed, and different levels of texture colors are prefiltered and stored per surfel. During rendering, a hierarchical forward warping algorithm projects surfels to a z-buffer. A novel method called visibility splatting determines visible surfels and holes in the z-buffer. Visible surfels are shaded using texture filtering, Phong illumination, and environment mapping using per-surfel normals. Several methods of image reconstruction, including supersampling, offer flexible speed-quality tradeoffs. Due to the simplicity of the operations, the surfel rendering pipeline is amenable for hardware implementation. Surfel objects offer complex shape, low rendering cost and high image quality, which makes them specifically suited for low-cost, real-time graphics, such as games.
Storage requirement estimation for data intensive applications with partially fixed execution ordering
Authors: Per Gunnar Kjeldsberg, Francky Catthoor, Einar J. Aas
Venue: Proceedings of the eighth international workshop on Hardware/software codesign (2000)

In this paper, we propose a novel storage requirement estimation methodology for use in the early system design phases when the data transfer ordering is only partly fixed. At that stage, none of the existing estimation tools are adequate, as they either assume a fully specified execution order or ignore it completely. Using a representative application demonstrator, we show how our technique can effectively guide the designer to achieve a transformed specification with low storage requirement.
Concept based design of data warehouses: the DWQ demonstrators
Authors: M. Jarke, C. Quix, D. Calvanese, M. Lenzerini, E. Franconi, S. Ligoudistianos, P. Vassiliadis, Y. Vassiliou
Venue: ACM SIGMOD Record (2000)

The ESPRIT Project DWQ (Foundations of Data Warehouse Quality) aimed at improving the quality of DW design and operation through systematic enrichment of the semantic foundations of data warehousing. Logic-based knowledge representation and reasoning techniques were developed to control accuracy, consistency, and completeness via advanced conceptual modeling techniques for source integration, data reconciliation, and multi-dimensional aggregation. This is complemented by quantitative optimization techniques for view materialization, optimizing timeliness and responsiveness without losing the semantic advantages from the conceptual approach. At the operational level, query rewriting and materialization refreshment algorithms exploit the knowledge developed at design time. The demonstration shows the interplay of these tools under a shared metadata repository, based on an example extracted from an application at Telecom Italia.