ppxscal/embedding_network huggingface dataset:
Analysis of the Inexact Uzawa Algorithm for Saddle Point Problems
Authors: James H. Bramble, Joseph E. Pasciak, Apostol T. Vassilev
Venue: SIAM Journal on Numerical Analysis (1997)

In this paper, we consider the so-called "inexact Uzawa" algorithm for iteratively solving linear block saddle point problems. Such saddle point problems arise, for example, in finite element and finite difference discretizations of Stokes equations, the equations of elasticity, and mixed finite element discretization of second-order problems. We consider both the linear and nonlinear variants of the inexact Uzawa iteration. We show that the linear method always converges as long as the preconditioners defining the algorithm are properly scaled. Bounds for the rate of convergence are provided in terms of the rate of convergence for the preconditioned Uzawa algorithm and the reduction factor corresponding to the preconditioner for the upper left-hand block. In the case of nonlinear iteration, the inexact Uzawa algorithm is shown to converge provided that the nonlinear process approximating the inverse of the upper left-hand block is of sufficient accuracy. Bounds for the nonlinear iteration are given in terms of this accuracy parameter and the rate of convergence of the preconditioned linear Uzawa algorithm. Applications to the Stokes equations and mixed finite element discretization of second-order elliptic problems are discussed and, finally, the results of numerical experiments involving the algorithms are presented.
Automatic management of operating-system resources
Authors: Olin Shivers
Venue: Proceedings of the second ACM SIGPLAN international conference on Functional programming (1997)

One of the attractive features of functional programming languages is that they provide automatic management of the store, in the form of garbage collection. However, the benefits of automatic resource management can be applied to other resources as well. Scsh, a systems-programming dialect of Scheme, provides automatic resource management for operating-systems structures, notably processes, I/O channels, and signal events. This kind of automatic management extends the benefits of garbage collection---modularity, robustness, simplicity, and clarity---to new sets of objects in programming, and also gives us hints as to how operating systems should be structured from the perspective of functional programming languages.
Adaptive protocols for parallel discrete event simulation
Authors: Samir R. Das
Venue: Proceedings of the 28th conference on Winter simulation (1996)

This paper reviews issues concerning the design of adaptive protocols for parallel discrete event simulation (PDES). The need for adaptive protocols are motivated in the background of the synchronization problem that has driven much of the research in this field. Traditional conservative and optimistic protocols and their hybrid variants are also discussed. Adaptive synchronization protocols are reviewed with special reference to their characteristics regarding the aspects of the simulation state that influence the adaptive decisions and the control parameters used. Finally, adaptive load management and scheduling strategies and their relationship to the synchronization protocol are discussed.
Spatio-temporal grouping for the formation of vascular segments in coronarography image sequences
Authors: C. Toumoulin, F. Mao
Venue: Technology and Health Care (1997)

This work is aimed at the extraction of vascular structures using perceptual grouping methods. The approach is based on structural feature matching, between images in the time sequence. These features correspond to junctions (or bifurcation points) and are paired by means of a local criteria. A global refinement procedure is then applied by means of a relaxation scheme. The feature trajectories over the entire image sequence are examined to further build sets of vascular segments, which better describe vascular branches. The resulting performances are exemplified on a standard biplane coronarographic examination.
CLIP: an optimizing layout generator for two-dimensional CMOS cells
Authors: Avaneendra Gupta, John P. Hayes
Venue: Proceedings of the 34th annual Design Automation Conference (1997)

We present a novel technique CLIP for optimizing both theheight and width of CMOS cell layouts in the two-dimensional (2-D) style. CLIP is based on integer-linear programming (ILP) and proceeds in two stages: First, an ILP model is used to determine a 2-D layout of minimum width W cell . Then, another model generatesa 2-D layout that has width W cell and requires a minimumnumber of routing tracks. Run times are in seconds for circuitswith up to 16 transistors. For larger circuits, we extend CLIP to ahierarchical method HCLIP that places series-connected transistorscontiguously. This reduces run times by up to three orders ofmagnitude, and still yields optimal results in over 80% of cases.
How to achieve modularity in distributed object allocation
Authors: Franco Zambonelli
Venue: ACM SIGPLAN Notices (1997)

The paper focuses on language constructs for driving the allocation of parallel object-oriented applications onto a target architecture. The paper analyses the issues that arise in the definition of these constructs and presents the solutions adopted in several systems and programming environments, by discussing their capability of enforcing the principle of modularity. Open issues and future directions of research are outlined.
Modelling of computer systems: a tutorial
Authors: Edward D. Lazowska
Venue: Proceedings of the 17th conference on Winter simulation (1985)

Computer system performance modelling is a relatively restricted problem domain. Because of this, much is known about which performance measures are and are not important, which system characteristics do and do not influence these performance measures, what degree of confidence the available measurement data will and will not support, what approximations are and are not reasonable, etc. Because computer systems are large, and because modelling is used as a regular part of the &ldquo;capacity planning&rdquo; process at many installations, fast and acceptably accurate analytic techniques have been developed for many applications. But because these analytic techniques do not accommodate certain important system characteristics, and because they do not yield certain important performance measures, simulation and hybrid analytic/simulation techniques also are of considerable importance. Computer system performance modelling thus provides a nice case study of the tradeoffs between simulation and analysis. These are the sorts of issues that will be discussed in this tutorial. In addition, since WSC attendees are apt not to be familiar with the techniques of analytic modelling, a brief overview of this material will be presented. In brief outline form: Applications of computer system performance modelling. A small set of case studies will be used to exhibit the range of problems that are considered. An introduction to analytic models. A brief discussion of how analytic queueing network models differ from their simulation counterparts: their inputs, their outputs, and the evaluation techniques that transform the inputs into the outputs. The case for analytic models. The key strength of analytic models is not that they're accurate; rather, it's that they provide ballpark projections very quickly. In what situations is this especially advantageous? The case for simulation models. Situations will be discussed in which simulation is the appropriate tool for computer system performance modelling: situations in which system characteristics or required performance measures preclude an analytic approach. The interplay of analysis and simulation. A discussion of areas such as the analysis of models via decomposition, hybrid analytic/simulation models, etc. Much of this material is based on the 1984 Prentice-Hall text Quantitative System Performance: Computer System Analysis Using Queueing Network Models by Edward D. Lazowska, John Zahorjan, G. Scott Graham, and Kenneth C. Sevcik, and on the 1984 AUERBACH portfolio Capacity Planning Using Queueing Network Models by Edward D. Lazowska.
An interactive maze router with hints
Authors: Michael H. Arnold, Walter S. Scott
Venue: Proceedings of the 25th ACM/IEEE Design Automation Conference (1988)

This paper presents the Irouter, an interactive maze router for the Magic IC layout editor that takes hints. The Irouter is a flexible tool intended to be useful wherever tight or unusual constraints do not permit automatic routing. It has already been used in the layout of an 80,000 transistor CMOS chip developed by our group at LLNL, and is currently being used to route the control signals of a 100,000 transistor, high performance, FPU chip being developed by the Berkeley SPUR project. Several novel ideas for maze routing have been developed in the Irouter. Hint layers permit the user to map out the general path of a route and pull the route in desired directions, while leaving details, such as obeying the design rules, to the router. The gross structure of the layout is preprocessed to facilitate accurate estimates of cost to completion during routing and hence effective pruning of misdirected partial routes. A windowed search strategy slowly shifts the focus from the start point towards the goal. This permits the consideration of alternatives at all stages of routing without blowing up into an exhaustive search.
No Arbitrage Between Economies and Correlation Risk Management
Authors: Hélyette Geman, Rémi Souveton
Venue: Computational Economics (1997)

The first goal of this paper is to clarify the implications of the no arbitrage assumption in the context of several countries and extend to a general setting of continuous-time finance and stochastic interest rates results which were more or less present in classical finance models such as the international APT (see Solnik (1983)). In particular, the remarkable relationship between the risk premia in two different countries and the sole volatility of the exchange rate is easily derived. Secondly, we examine the pricing and hedging of cross-currencies options when interest rates are stochastic in all countries. The dependence of risk neutrality arguments on the reference num&eacute;raire as developed in Geman (1989) becomes particularly clear in the case of several currencies.
Optimal Parallel Routing in Star Networks
Authors: Chi-Chang Chen, Jianer Chen
Venue: IEEE Transactions on Computers (1997)

Star networks have recently been proposed as attractive alternatives to the popular hypercube for interconnecting processors on a parallel computer. In this paper, we present an efficient algorithm that constructs an optimal parallel routing in star networks. Our result improves previous results for the problem.
Computer managed, open question, open book assessment
Authors: John Rosbottom
Venue: Proceedings of the 2nd conference on Integrating technology into computer science education (1997)

This paper describes the development and use of practical examinations which include a significant element of software control of the administrative process. The educational methodology is novel in that the assessment is 'open question'. This means that students are given a set of practical exercises some weeks in advance of the date of the examination. The examination is also 'open book' so that students can consult various sources of information to help them complete the task. However the 'open book' element is restricted to prevent students accessing pre-prepared solutions. The computer system manages several elements of the assessment process.
A member lookup algorithm for C++
Authors: G. Ramalingam, Harini Srinivasan
Venue: Proceedings of the ACM SIGPLAN 1997 conference on Programming language design and implementation (1997)

The member lookup problem in C++ is the problem of resolving a specified member name in the context of a specified class. Member lookup in C++ is complicated by the presence of virtual inheritance and multiple inheritance. In this paper, we present an efficient algorithm for member lookup in C++. We also present a formalism for the multiple inheritance mechanism of C++, which we use as the basis for deriving our algorithm. The formalism may also be of use as a formal basis for deriving other C++ compiler algorithms.
The MASC/BGMP architecture for inter-domain multicast routing
Authors: Satish Kumar, Pavlin Radoslavov, David Thaler, Cengiz Alaettinoğlu, Deborah Estrin, Mark Handley
Venue: ACM SIGCOMM Computer Communication Review (1998)

Multicast routing enables efficient data distribution to multiple recipients. However, existing work has concentrated on extending single-domain techniques to wide-area networks, rather than providing mechanisms to realize inter-domain multicast on a global scale in the Internet.We describe an architecture for inter-domain multicast routing that consists of two complementary protocols. The Multicast Address-Set Claim (MASC) protocol forms the basis for a hierarchical address allocation architecture. It dynamically allocates to domains multicast address ranges from which groups initiated in the domain get their multicast addresses. The Border-Gateway Multicast Protocol (BGMP), run by the border routers of a domain, constructs inter-domain bidirectional shared trees, while allowing any existing multicast routing protocol to be used within individual domains. The resulting shared tree for a group is rooted at the domain whose address range covers the group's address; this domain is typically the group initiator's domain. We demonstrate the feasibility and performance of these complementary protocols through simulation.This architecture, together with existing protocols operating within each domain, is intended as a framework in which to solve the problems facing the current multicast addressing and routing infrastructure.
A digital fountain approach to reliable distribution of bulk data
Authors: John W. Byers, Michael Luby, Michael Mitzenmacher, Ashutosh Rege
Venue: Proceedings of the ACM SIGCOMM '98 conference on Applications, technologies, architectures, and protocols for computer communication (1998)

The proliferation of applications that must reliably distribute bulk data to a large number of autonomous clients motivates the design of new multicast and broadcast protocols. We describe an ideal, fully scalable protocol for these applications that we call a digital fountain. A digital fountain allows any number of heterogeneous clients to acquire bulk data with optimal efficiency at times of their choosing. Moreover, no feedback channels are needed to ensure reliable delivery, even in the face of high loss rates.We develop a protocol that closely approximates a digital fountain using a new class of erasure codes that for large block sizes are orders of magnitude faster than standard erasure codes. We provide performance measurements that demonstrate the feasibility of our approach and discuss the design, implementation and performance of an experimental system.
A signature based approach to regularity extraction
Authors: Srinivasa R. Arikati, Ravi Varadarajan
Venue: Proceedings of the 1997 IEEE/ACM international conference on Computer-aided design (1997)

Regularity extraction is an important step in the design flow of datapath-dominated circuits. This paper outlines a new method that automatically extracts regular structures from the netlist. The method is general enough to handle two types of designs: designs with structured cluster information for a portion of the datapath components that are identified at the HDL level; and designs with no such structured cluster information. The method analyzes the circuit connectivity and uses signature based approaches to recognize regularity.
On determining the distribution of software response times
Authors: Charles M. Shub
Venue: Proceedings of the 17th conference on Winter simulation (1985)

This paper reports on a simulation model for predicting software response time in symmetric distributed computing systems. This model extends previous work by considering a collection of similar processing elements connected together by some interconnection mechanism. The model also extends previous work by considering stimuli that require processing at multiple priority levels. The paper begins by describing the nature of the problem. In this section, the overall problem is decomposed so that attention may be focused on the software response, the topic of this report. Next a model is formulated. The coding of the model in GPSS/H is described. Finally, sample results are presented.
The effects of lexical specialization on the growth curve of the vocabulary
Authors: R. Harald Baayen
Venue: Computational Linguistics (1996)

The number of different words expected on the basis of the urn model to appear in, for example, the first half of a text, is known to overestimate the observed number of different words. This paper examines the source of this overestimation bias. It is shown that this bias does not arise due to sentence-bound syntactic constraints, but that it is a direct consequence of topic cohesion in discourse. The nonrandom, clustered appearance of lexically specialized words, often the key words of the text, explains the main trends in the overestimation bias both quantitatively and qualitatively. The effects of nonrandomness are so strong that they introduce an overestimation bias in distributions of units derived from words, such as syllables and digrams. Nonrandom words usage also affects the accuracy of the Good-Turing frequency estimates which, for the lowest frequencies, reveal a strong underestimation bias. A heuristic adjusted frequency estimate is proposed that, at least for novel-sized texts, is considerably more accurate.
Compiling APL for parallel execution on an FFP machine
Authors: Alexis Koster
Venue: ACM SIGAPL APL Quote Quad (1985)

This paper investigates the features of an APL compiler designed for a cellular computer (the FFP machine). This machine directly executes Formal Functional Programming (FFP) code. The APL compiler generates parallel FFP code. Techniques for parallel implementation of many APL array processing operators and functions are described. The implicit parallelism between different operations in a given APL program is also exploited. The FFP machine can accommodate the almost unbounded parallelism of FFP programs. Execution time analysis shows potential for highly efficient execution of APL programs on this machine.
Parallel Image Component Labeling With Watershed Transformation
Authors: Alina N. Moga, Moncef Gabbouj
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1997)

The parallel watershed transformation used in gray scale image segmentation is reconsidered in this paper on the basis of the component labeling problem. The main idea is to break the sequentiality of the watershed transformation and to correctly delimit the extent of all connected components locally, on each processor, simultaneously. The internal fragmentation of the catchment basins, due to domain decomposition, into smaller subcomponents is ulteriorly solved by employing a global connected components operator. Therefore, in a pyramidal structure of master-slave processors, internal contours of adjacent subcomponents within the same component are hierarchically removed. Global final connected areas are efficiently obtained in log2N steps on a logical grid of N processors. Timings and segmentation results of the algorithm built on top of the Message Passing Interface (MPI) and tested on the Cray T3D are brought forward to justify the superiority of the novel design solution compared against previous implementations.
Implementation of a database factory
Authors: Asokan R. Selvaraj, Debasish Ghosh
Venue: ACM SIGPLAN Notices (1997)

Object oriented software systems that utilize relational databases for data-store have to deal with the problem of interfacing to the relational data. This aspect of the software is more relevant to the solution domain rather than the problem domain i.e., the business requirements of an application do not dictate that there be a mechanism that allows the application to store and retrieve relational data. Hence, de-coupling the application from the database and its interface is relevant from the perspective of portability that of the application to other kinds of databases. For example, it is conceivable the application may be required to work with relational databases from different vendors. This article shows an adaptation of the Factory Method Pattern and the Abstract Factory Pattern [1] as a generic solution to the problem of de-coupling application code from the underlying database and its associated interface mechanisms.
A simulation-based controller builder for flexible manufacturing systems
Authors: Fernando G. Gonzalez
Venue: Proceedings of the 28th conference on Winter simulation (1996)

This paper discusses a new simulation and control prototype software package that can be employed as a controller for a simple FMS. In developing this software, we attempted to achieve a compromise between the program ming flexibility of a general-purpose language like C++ and the convenience of a simulation language like SIMAN (see Pegden et al. [ 1995]). In particular, we desire to provide standard programming features within the model such as recursive function calls while providing a single model which can be used to simulate and control a real-world system. To test the efficacy of the developed simulation tool, we developed a simulation model which can control a physical emulator of an FMS which has been constructed in our research laboratory.
Formal modeling and analysis of the HLA component integration standard
Authors: Robert J. Allen, David Garlan, James Ivers
Venue: Proceedings of the 6th ACM SIGSOFT international symposium on Foundations of software engineering (1998)

An increasingly important trend in the engineering of complex systems is the design of component integration standards. Such standards define rules of interaction and shared communication infrastructure that permit composition of systems out of independently-developed parts. A problem with these standards is that it is often difficult to understand exactly what they require and provide, and to analyze them in order to understand their deeper properties. In this paper we use our experience in modeling the High Level Architecture (HLA) for Distributed Simulation to show how one can capture the structured protocol inherent in an integration standard as a formal architectural model that can be analyzed to detect anomalies, race conditions, and deadlocks.
Teaching with object oriented libraries
Authors: Nick Parlante
Venue: ACM SIGCSE Bulletin (1997)

This paper describes a new course centered around the use of large object-oriented libraries and the distinct skills required to use them effectively. The paper describes the needs which led to the formation of the new course, an outline of the course's goals, topics and projects, and observations and conclusions from the course's first offerings.
A Convergent Algorithm for the Output Covariance Constraint Control Problem
Authors: G. Zhu, M. A. Rotea, R. Skelton
Venue: SIAM Journal on Control and Optimization (1997)

This paper considers the optimal control problem of minimizing control effort subject to multiple performance constraints on output covariance matrices $Y_i$ of the form $Y_i \leq \overline{Y}_i$, where $\overline{Y}_i$ is given. The contributions of this paper are a set of conditions that characterize global optimality, and an iterative algorithm for finding a solution to the optimality conditions. This iterative algorithm is completely described up to a user-specified parameter. We show that, under suitable assumptions on problem data, the iterative algorithm converges to a solution of the optimality conditions, provided that this parameter is properly chosen. Both discrete- and continuous-time problems are considered.