ppxscal/embedding_network huggingface dataset:
System aspects of sharing a virtual reality: CVE '98 workshop report
Authors: Michael Capps, Samuli Pekkola, Chris Greenhalgh
Venue: ACM SIGGROUP Bulletin (1998)

We have recently held the second annual "System Aspects of Sharing a Virtual Reality" workshop, in conjunction with CVE '98 (see report in this issue). The single-day format allowed for twelve presentations plus discussion, which are summarized below. The topics addressed were: designing systems to cope with network limitations; managing communication and information; the construction of systems and toolkits; issues of presentation and user interaction; and application development and evaluation.
A theory of core fudgets
Authors: Colin J. Taylor
Venue: Proceedings of the third ACM SIGPLAN international conference on Functional programming (1998)

The Fudgets system is a toolkit for developing graphical applications in the lazy functional programming language Haskell. In this paper we develop an operational semantics for a subset of this system, inspired by ideas from concurrency theory. A semantic theory based on bisimulation is defined and shown to be a congruence. We consider two applications of this theory: firstly, some equational rules useful for reasoning about Fudget programs are verified; secondly, we show how the operational semantics can be used to check the correctness of implementations of the Fudgets system.
Formal Requirements Analysis of an Avionics Control System
Authors: Bruno Dutertre, Victoria Stavridou
Venue: IEEE Transactions on Software Engineering (1997)

We report on a formal requirements analysis experiment involving an avionics control system. We describe a method for specifying and verifying real-time systems with PVS. The experiment involves the formalization of the functional and safety requirements of the avionics system as well as its multilevel verification. First level verification demonstrates the consistency of the specifications whilst the second level shows that certain system safety properties are satisfied by the specification. We critically analyze methodological issues of large scale verification and propose some practical ways of structuring verification activities for optimizing the benefits.
An Optimal Preconditioner for a Class of Saddle Point Problems with a Penalty Term
Authors: Axel Klawonn
Venue: SIAM Journal on Scientific Computing (1998)

Iterative methods are considered for a class of saddle point problems with a penalty term arising from finite element discretizations of certain elliptic problems. An optimal preconditioner which is independent of the discretization and the penalty parameter is constructed. This approach is then used to design an iterative method with a convergence rate bounded independently of the Lamé parameters occurring in the equations of linear elasticity.
Teaching simulation to undergraduate liberal arts students
Authors: Maurice F. Aburdene, Alan D. Wilcox
Venue: Proceedings of the 17th conference on Winter simulation (1985)

Few colleges and universities in the United States teach simulation courses to undergraduate liberal arts students. Simulation was born and grew up in engineering, but it may attain its greatest sophistication in a new realm, the liberal arts. This paper suggests that a course in simulation for undergraduate liberal arts students is important and presents a course outline for it. Our experience with teaching the course is presented.
Self-Organizing Maps for the Analysis of Complex Movement Patterns
Authors: H. U. Bauer, W. Schöllhorn
Venue: Neural Processing Letters (1997)

We apply the Self-Organizing-Map-algorithm (SOM) as a central processing step in a new scheme for the characterisation of movement patterns of athletes. Due to its non-linear dimension reduction capabilities, the SOM outperforms a direct processing of the data as well as preprocessing using principal component analysis. Our results open the way to an objective assessment of movement patterns, with possible applications in the sport sciences as well as in medicine.
Time efficient VLSI artwork analysis algorithms in GOALIE2
Authors: Kuang-Wei Chiang, Surendra Nahar, Chi-Yuan Lo
Venue: Proceedings of the 25th ACM/IEEE Design Automation Conference (1988)

New algorithms used in the GOALIE2 circuit extraction system, based on representing VLSI layout geometries as trapezoids, are presented in this paper. These include polygon-to-trapezoid decomposition, scanline management, and output sorting. In particular, the scanline algorithm virtually eliminates all redundant computation present in similar systems. These algorithms enable us to perform VLSI layout analysis in nearly linear time.
Combination of Multiple Classifiers Using Local Accuracy Estimates
Authors: Kevin Woods, W. Philip Kegelmeyer,  Jr., Kevin Bowyer
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1997)

This paper presents a method for combining classifiers that uses estimates of each individual classifier's local accuracy in small regions of feature space surrounding an unknown test sample. An empirical evaluation using five real data sets confirms the validity of our approach compared to some other Combination of Multiple Classifiers algorithms. We also suggest a methodology for determining the best mix of individual classifiers.
A practical framework for demand-driven interprocedural data flow analysis
Authors: Evelyn Duesterwald, Rajiv Gupta, Mary Lou Soffa
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1997)

The high cost and growing importance of interprocedural data flow analysis have led to an increased interest in demand-driven algorithms. In this article, we present a general framework for developing demand-driven interprocedural data flow analyzers and report our experience in evaluating the performance of this approach. A demand for data flow information is modeled as a set of queries. The framework includes a generic demand-driven algorithm that determines the response to query by iteratively applying a system of query propagation rules. The propagation rules yield precise responses for the class of distributive finite data flow problems. We also describe a two-phase framework variation to accurately handle nondistributive problems. A performance evaluation of our demand-driven approach is presented for two data flow problems, namely, reaching-definitions and copy constant propagation. Our experiments show that demand-driven analysis performs well in practice, reducing both time and space requirements when compared with exhaustive analysis.
Ideas for kick-starting the Ada market of the 1990s
Authors: S. Tucker Taft
Venue: Proceedings of the conference on TRI-ADA '90 (1990)

There are several impediments to Ada's acceptance in the mainstream. The Ada 9X project should do its best to eliminate as many of these as possible. Unfortunately, the biggest is probably the chicken-and-egg problem. More programmers use a language when more platforms and tool vendors support it; more tool vendors support a language when there is a bigger market. However, here are some things which could be done or are already being done to help &ldquo;kick start&rdquo; the Ada market: Produce a small and fast public-domain Ada front-end. Define a standard interface between compilers and Ada run-time systems, allowing third-party RTS development. Support the development and implementation of Ada bindings to X windows, SQL, networking/remote-procedure-calls, etc. Open up the language to first-class abstract data types, user defined real-time synchronization mechanisms, and call-in/call-out with C, COBOL, and FORTRAN. Provide a &ldquo;safe&rdquo; alternative to C/C++, with excellent compile-time and run-time checking without necessarily sacrificing flexibility or efficiency. We hope that in our role as the mapping/revision contractor, we can contribute to these goals, both by refinements to the definition of Ada, and by encouraging an ongoing process to address the non-technical impediments to Ada acceptance.
An approach for exploring code improving transformations
Authors: Deborah L. Whitfield, Mary Lou Soffa
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1997)

Although code transformations are routinely applied to improve the performance of programs for both scalar and parallel machines, the properties of code-improving transformations are not well understood. In this article we present a framework that enables the exploration, both analytically and experimentally, of properties of code-improving transformations. The major component of the framework is a specification language, Gospel, for expressing the conditions needed to safely apply a transformation and the actions required to change the code to implement the transformation. The framework includes a technique that facilitates an analytical investigation of code-improving transformations using the Gospel specifications. It also contains a tool, Genesis, that automatically produces a transformer that implements the transformations specified in Gospel. We demonstrate the usefulness of the framework by exploring the enabling and disabling properties of transformations. We first present analytical results on the enabling and disabling properties of a set of code transformations, including both traditional and parallelizing transformations, and then describe experimental results showing the types of transformations and the enabling and disabling interactions actually found in a set of programs.
Highly concurrent cache consistency for indices in client-server database systems
Authors: Markos Zaharioudakis, Michael J. Carey
Venue: Proceedings of the 1997 ACM SIGMOD international conference on Management of data (1997)

In this paper, we present four approaches to providing highly concurrent B+-tree indices in the context of a data-shipping, client-server OODBMS architecture. The first performs all index operations at the server, while the other approaches support varying degrees of client caching and usage of index pages. We have implemented the four approaches, as well as the 2PL approach, in the context of the SHORE OODB system at Wisconsin, and we present experimental results from a performance study based on running SHORE on an IBM SP2 multicomputer. Our results emphasize the need for non-2PL approaches and demonstrate the tradeoffs between 2PL, no-caching, and the three caching alternatives.
A distributed garbage collector with diffusion tree reorganisation and mobile objects
Authors: Luc Moreau
Venue: Proceedings of the third ACM SIGPLAN international conference on Functional programming (1998)

We present a new distributed garbage collection algorithm that is able to reorganise diffusion trees and to support mobile objects. It has a modular design comprising three components: a reliable transport mechanism, a reference-counting based distributed garbage collector for non-mobile objects, and an extra layer that provides mobility. The algorithm is formalised by an abstract machine and is proved to be correct. The safety property ensures that an object may not be reclaimed as long as it is referred to locally or remotely. The liveness property guarantees that unreachable objects will eventually be reclaimed. The mobility property certifies that messages are always forwarded towards more recent mobile object positions.
Automated Meta-Control for Adaptable Real-Time Software
Authors: Jair Jehuda, Amos Israeli
Venue: Real-Time Systems (1998)

The software meta-controller is an online agent responsible for dynamically adapting an application&lsquo;s software configuration, e.g. altering operational modes and migrating tasks, to best accommodate varying runtime circumstances. In distributed real-time applications such adaptations must be carried out in a manner which maintains the schedulability of all critical tasks while maximizing some notion of system value for all other tasks. For large-scale real-time applications, considering all possible adaptations at the task-level is computationally intractable. This paper presents an automated aggregate approach to software meta-control, appropriate for large-scale distributed real-time systems. The aggregate automated meta-control problem is still NP-hard, but it has very practical approximate solutions. Introduced, here, are two very-effective approximation algorithms, QDP and GG, with very reasonable polynomial time complexity. Both algorithms also provide us with upper bounds for optimum system values, useful for deriving absolute, albeit somewhat pessimistic, measures of actual performance. Extensive Monte Carlo analysis is used to illustrate that expected performance for both algorithms is generally suboptimal by no more than a few percent. Our flexible software meta-control model is also shown to be readily applied to a wide range of time-sensitive applications.
Intelligent animated agents for interactive language training
Authors: Ron Cole, Tim Carmell, Pam Connors, Mike Macon, Johan Wouters, Jacques de Villiers, Alice Tarachow, Dominic Massaro, Michael Cohen, Jonas Beskow, Jie Yang, Uwe Meier, Alex Waibel, Pat Stone, Alice Davis, Chris Soland, George Fortier
Venue: Issue 61 (June 1998) (1998)

This report describes a three-year project, now eight months old, to develop interactive learning tools for language training with profoundly deaf children. The tools combine four key technologies: speech recognition, developed at the Oregon Graduate Institute; speech synthesis, developed at the University of Edinburgh and modified at OGI; facial animation, developed at University of California, Santa Cruz; and face tracking and speech reading, developed at Carnegie Mellon University. These technologies are being combined to create an intelligent conversational agent; a three-dimensional face that produces and understands auditory and visual speech. The agent has been incorporated into CSLU Toolkit, a software environment for developing and researching spoken language systems. We describe our experiences in bringing interactive learning tools to classrooms at the Tucker-Maxon Oral School in Portland, Oregon, and the technological advances that are required for this project to succeed.
An object-oriented framework for block preconditioning
Authors: Edmond Chow, Michael A. Heroux
Venue: ACM Transactions on Mathematical Software (TOMS) (1998)

General software for preconditioning the iterative solution of linear systems is greatly lagging behind the literature. This is partly because specific problems and specific matrix and preconditioner data structures in order to be solved efficiently, i.e., multiple implementations of a preconditioner with specialized data structures are required. This article presents a framework to support preconditioning with various, possibly user-defined, data structures for matrices that are partitioned into blocks. The main idea is to define data structures for the blocks, and an upper layer of software which uses these blocks transparently of their data structure. This transparency can be accomplished by using an object-oriented language. Thus, various preconditioners, such as block relaxations and block-incomplete factorizations, only need to be defined once and will work with any block type. In addition, it is possible to transparently interchange various approximate or exact techniques for inverting pivot blocks, or solving systems whose coefficient matrices are diagonal blocks. This leads to a rich variety of preconditioners that can be selected. Operations with the blocks are performed with optimized libraries or fundamental data types. Comparisons with an optimized Fortran 77 code on both workstations and Cray supercomputers show that this framework can approach the efficiency of Fortran 77, as long as suitable block sized and block types are chosen.
Visualisation in the Simulation and Control of Economic Models
Authors: R. D. Herbert, R. D. Bell
Venue: Computational Economics (1997)

Simulation of economic models is frequently used in the investigation of economic policy. Yet one of the problems with simulation is that it can be difficult to appreciate the model properties due to the nature of the simulation process. Stochastic simulation, for example, can produce large quantities of output which can be difficult to comprehend. Further, when mathematically sophisticated techniques such as the use of optimal control and Kalman Filtering are applied to models, the simulation process can become even more complex. Visualisation techniques in model building, simulation, and analysis of simulation output can help reduce the complexity. This is especially the case with interactive simulation. In this paper we investigate the use of visualisation in simulation by examining the application of optimal control techniques to a stochastic forward looking analytic economic model. We also use interactive object oriented simulation software where objects, such as components of models or graphs of outputs, can be visually manipulated to form simulation systems. We find that the use of visualisation can make the investigation of policy analysis issues with such models more comprehensible.
Improving the PVM teaching environment
Authors: Chris McDonald, Kamran Kazemi
Venue: ACM SIGCSE Bulletin (1997)

The parallel programming community has long recognized the need for a simple programming environment offering interprocess communication between heterogeneous systems. As the Parallel Virtual Machine environment, PVM, has emerged to meet this goal, an increasing number of educational institutions are choosing PVM to support their teaching of parallel and distributed computing using networks of workstations. However, it is often the nature of PVM's design and implementation that can severely limit its success in a teaching environment. This paper first motivates and then describes improvements to the PVM environment which increase both robustness and efficiency in an educational setting.
New advances and applications of combining simulation and optimization
Authors: Fred Glover, James P. Kelly, Manuel Laguna
Venue: Proceedings of the 28th conference on Winter simulation (1996)

The design of efficient parallel discrete-event simulation (PDES) models often appears to be a mysterious art practiced primarily by academic researchers who have been rigorously ordained in this task. This tutorial attempts to unravel some of the mysteries. It describes the process of generating an efficient parallel implementation of a discrete-event simulation (DES) model. Common pitfalls in the parallel execution of the models are described together with suggestions on their avoidance.
Boundary-valued shape-preserving interpolating splines
Authors: P. Costantini
Venue: ACM Transactions on Mathematical Software (TOMS) (1997)

This article describes a general-purpose method for computing interpolating polynomial splines with arbitrary constraints on their shape and satisfying separable or nonseparable boundary conditions. Examples of applications of the related Fortran code are periodic shape-preserving spline intepolation and the construction of visually pleasing closed curves.
Ada run-time system contention measurement
Authors: J. F. Barhorst, R. W. Seelye
Venue: Proceedings of the conference on TRI-ADA '90 (1990)

The escalating operational requirements of DoD mission-critical real-time embedded (RTE) computer systems require the increasing use of multiprocessor architectures. In order to fully exploit the performance benefits of multiprocessor systems, efficient Ada run-time systems need to be developed. The sources and effects of contention within such systems must be understood and minimized in order to use Ada effectively and efficiently on multiprocessor run-time systems. This paper presents the results of our analysis and conversion of an existing Ada run-time system to a tightly coupled multiprocessor run-time system that supports the dynamic scheduling of Ada tasks. The effect on system performance from contention for critical regions of the multiprocessor system was measured.
An Area-Effective Cell-Based Channel Decoder LSI For a Digital Satellite TV Broadcasting
Authors: Takehiro Kamada, Toshihiko Fukuoka, Yuji Nakai, Yoshihiko Fukumoto, Yasuhiro Nakakura, Katsuhiko Ueda, Tomonori Shiomi, Kazuhiro Ota
Venue: Journal of VLSI Signal Processing Systems (1998)

A new channel decoder LSI, which will be used in digital satellite TV broadcasting Set-Top Boxes, has been designed. This LSI&lsquo;s functions include AD/DA conversion, QPSK demodulating, Viterbi decoding, frame synchronization, convolutional deinterleaving, Reed-Solomon (RS) decoding, and descrambling. We use a new method for Viterbi Decoding called the Tracking Survivor State Information (TSSI) method, which not only reduces power consumption, but also solves the problem of increasing memory size. To reduce the size of RS decoder circuit, we used a three-stage-pipeline structure as well as designed a new architecture to realize Euclid&lsquo;s algorithm. This device has been fabricated in a 0.35 &micro;m 3-metal CMOS standard cell-based process and is composed of 670 K transistors. In this paper, we describe the TSSI method of the Viterbi Decoder and the Reed-Solomon Decoder&lsquo;s new 3-stage pipeline architecture.
Profile-driven program synthesis for evaluation of system power dissipation
Authors: Cheng-Ta Hsieh, Massoud Pedram, Gaurav Mehta, Fred Rastgar
Venue: Proceedings of the 34th annual Design Automation Conference (1997)

This paper presents a new approach for estimatingpower dissipation in a high performance microprocessor chip.First, characteristic profile (including parameters such as thecache miss rate, branch prediction miss rate, pipeline stalls,instruction mix, memory references, etc.) is extracted fromapplication programs. Then, mixed integer linear programmingand heuristic rules are used to gradually transform a genericprogram template to into a fully functional program. Thesynthesized program exhibits the same performance and powerdissipation behavior (as characterized by the extracted profile),yet it has an instruction trace orders of magnitude smaller thanthe initial trace. The synthesized program is subsequentlysimulated on a register-transfer level description of the targetmicroprocessor to provide the power dissipation value. Resultsobtained for the Intel's Pentium processor executing standardbenchmark programs show a simulation time reduction by 3-5orders of magnitude.
PAL: A Pattern-Based First-Order Inductive System
Authors: Eduardo F. Morales
Venue: Machine Learning (1997)

It has been argued that much of human intelligence can be viewed as the process of matching stored patterns. In particular, it is believed that chess masters use a pattern&ndash;based knowledge to analyze a position, followed by a pattern&ndash;based controlled search to verify or correct the analysis. In this paper, a first&ndash;order system, called PAL, that can learn patterns in the form of Horn clauses from simple example descriptions and general purpose knowledge is described. The learning model is based on (i) a constrained least general generalization algorithm to structure the hypothesis space and guide the learning process, and (ii) a pattern&ndash;based representation knowledge to constrain the construction of hypothesis. It is shown how PAL can learn chess patterns which are beyond the learning capabilities of current inductive systems. The same pattern&ndash;based approach is used to learn qualitative models of simple dynamic systems and counterpoint rules for two&ndash;voice musical pieces. Limitations of PAL in particular, and first&ndash;order systems in general, are exposed in domains where a large number of background definitions may be required for induction. Conclusions and future research directions are given.
The Length of Primitive BCH Codes with Minimal Covering Radius
Authors: Stephen D. Cohen
Venue: Designs, Codes and Cryptography (1997)

It is proved that the covering radius of a primitive binary BCH code of length q-1 and designed distance 2t+1, where \[ q=2^m>[(2t-3)(2t-1)!]^2, \] is exactly 2t-1 (the minimum value possible). The bound for q is significantly lower than the one obtained by O. Moreno and C. J. Moreno [9].