ppxscal/embedding_network huggingface dataset:
Parallel simulation of the IBM SP2 interconnection network
Authors: Caroline Benveniste, Philip Heidelberger
Venue: Proceedings of the 27th conference on Winter simulation (1995)

Simulations of large multistage interconnection networks used in parallel processing systems are computationally expensive. The paper describes the parallel simulation of a realistic and highly detailed model of the IBM SP2 interconnection network. The challenges involved in efficiently parallelizing such a complex simulation are discussed.
A methodology for active, student-controlled learning: motivating our weakest students
Authors: Curtis A. Carver, Richard A. Howard, William D. Lane
Venue: Proceedings of the twenty-seventh SIGCSE technical symposium on Computer science education (1996)

This paper outlines a methodology to improve the performance of the weakest students through networked hypermedia and in-class exercises. These efforts are an outgrowth of experiments using networked hypermedia in the form of the World Wide Web (WWW) as the basis for networked courseware [1-4]. While initial approaches significantly enhanced the performance of the average and best students, there was no noticeable gain in the performance of the weakest students [4]. They continued to come into class without preparing and expected to somehow condense the learning process into five 55-minute sections every two weeks. In order to enhance the performance of these students, a series of procedures were developed that should increase their performance while minimizing any negative impact on the rest of class. The first procedure uses a networked, Common Gateway Interface (CGI), form-based Student Response System to enhanced communications and expectations between the student and professor. The Student Response System automates the grading of homework assignments, and as a result, facilitates nightly homework assignments without increasing the grading load on the professor. The second component of this methodology involves developing a series of graded, in-class, group exercises that can be easily graded in-class, represents a substantial portion of the final grade, and requires a public presentation of the group's results. Together, these tools and practices form a methodology for reaching the weakest students and enhancing their performance.
Lag, drag, void and use&mdash;heap profiling and space-efficient compilation revisited
Authors: Niklas Röjemo, Colin Runciman
Venue: ACM SIGPLAN Notices (1996)

The context for this paper is functional computation by graph reduction. Our overall aim is more efficient use of memory. The specific topic is the detection of dormant cells in the live graph --- those retained in heap memory though not actually playing a useful role in computation. We describe a profiler that can identify heap consumption by such 'useless' cells. Unlike heap profilers based on traversals of the live heap, this profiler works by examining cells postmortem. The new profiler has revealed a surprisingly large proportion of 'useless' cells, even in some programs that previously seemed space-efficient such as the boot-strapping Haskell compiler nhc.
The Vesta parallel file system
Authors: Peter F. Corbett, Dror G. Feitelson
Venue: ACM Transactions on Computer Systems (TOCS) (1996)

The Vesta parallel file system is designed to provide parallel file access to application programs running on multicomputers with parallel I/O subsystems. Vesta uses a new abstraction of files: a file is not a sequence of bytes, but rather it can be partitioned into multiple disjoint sequences that are accessed in parallel. The partitioning&mdash;which can also be changed dynamically&mdash;reduces the need for synchronization and coordination during the access. Some control over the layout of data is also provided, so the layout can be matched with the anticipated access patterns. The system is fully implemented and forms the basis for the AIX Parallel I/O File System on the IBM SP2. The implementation does not compromise scalability or parallelism. In fact, all data accesses are done directly to the I/O node that contains the requested data, without any indirection or access to shared metadata. Disk mapping and caching functions are confined to each I/O node, so there is no need to keep data coherent across nodes. Performance measurements shown good scalability with increased resources. Moreover, different access patterns are show to achieve similar performance.
Alternative strategies to interpretative information systems
Authors: Gail Louw
Venue: Proceedings of conference on Organizational computing systems (1995)

The relentless move to computerisation in the National Health Service in the United Kingdom (NHS) is challenged in this paper. The distinction between two types of information is defined: proceduralised and interpretative. An alternative to the latter is presented that relies on a change in organisational structure in the form of a self contained unit. This effectively reduces the need to process information. The unit, based on the principles of Patient Focused Care, provide multiskilled teams using a combination of multi-disciplinary documentation and protocols of care to ensure effective communication takes place without the use of interpretative information systems.
Learning the initial state of a second-order recurrent neural network during regular-language inference
Authors: Mikel L. Forcada, Rafael C. Carrasco
Venue: Neural Computation (1995)

Recent work has shown that second-order recurrent neural networks (2ORNNs) may be used to infer regular languages. This paper presents a modified version of the real-time recurrent learning (RTRL) algorithm used to train 2ORNNs, that learns the initial state in addition to the weights. The results of this modification, which adds extra flexibility at a negligible cost in time complexity, suggest that it may be used to improve the learning of regular languages when the size of the network is small.
Switching activity analysis using Boolean approximation method
Authors: Taku Uchino, Fumihiro Minami, Takashi Mitsuhashi, Nobuyuki Goto
Venue: Proceedings of the 1995 IEEE/ACM international conference on Computer-aided design (1995)

This paper presents a novel algorithm to estimate the signal probability and switching activity at all nodes in a combinational logic circuit under a zero-delay model without constructing global BDDs. By using Taylor expansion technique, the first-order signal correlation effects due to reconvergent fan-out nodes are taken into account. High accuracy is achieved by considering the dependency of the signal probability and switching activity on each primary input. High speed is also achieved by using the incremental approach for probability calculation. Our approach is able to handle large circuits, since it does not need to construct global BDDs for the probability calculation. The analysis of the time complexity and the experimental results show the running time of our approach to be about 100 times shorter than that of the most accurate approach previously proposed and that our approach has comparable accuracy. The error of the total power estimation is about 0.5% on average.
Performance of a parallel global atmospheric chemical tracer model
Authors: James Demmel, Sharon Smith
Venue: Proceedings of the 1995 ACM/IEEE conference on Supercomputing (CDROM) (1995)

As partof a NASA HPCC Grand Challenge project, we are designing and implementing a parallel atmospheric chemical tracer model that will be suitable for use in global simulations. To accomplish this goal, our starting point has been an atmospheric pollution model that was originally used to study pollution in the Los Angeles Basin. The model includes gas-phase and aqueous-phase chemistry, radiation, aerosol physics, advection, convection, deposition, visibility and emissions. The potential bottlenecks in the model for parallel implementation are the compute-intensiveODE solving phase with load balancing problems,and the communication-intensive-advection phase. We describe the implementation and performance results on a variety of platforms,with emphasis on a detailed performance model we developed to predict performance, identify bottlenecks, guide our implementation, assess scalability, and evaluate architectures. An atmospheric chemical tracer model such as the one we describe in this paper will be one component of a larger Earth Systems Model (ESM), being developed under the direction of C. R. Mechoso of UCLA, incorporating atmospheric dynamics, atmospheric physics, ocean dynamics, and a database and visualization system.
Enhancing database correctness: a statistical approach
Authors: Wen-Chi Hou, Zhongyang Zhang
Venue: Proceedings of the 1995 ACM SIGMOD international conference on Management of data (1995)

In this paper, we introduce a new type of integrity constraint, which we call a statistical constraint, and discuss its applicability to enhancing database correctness. Statistical constraints manifest embedded relationships among current attribute values in the database and are characterized by their probabilistic nature. They can be used to detect potential errors not easily detected by the conventional constraints. Methods for extracting statistical constraints from a relation and enforcement of such constraints are described. Preliminary performance evaluation of enforcing statistical constraints on a real life database is also presented.
Principles and applications of chaotic systems
Authors: William Ditto, Toshinori Munakata
Venue: Communications of the ACM (1995)

There lies a behavior between rigid regularity and randomness based on pure chance. It's called a chaotic system, or chaos for short [5]. Chaos is all around us. Our notions of physical motion or dynamic systems have encompassed the precise clock-like ticking of periodic systems and the vagaries of dice-throwing chance, but have often been overlooked as a way to account for the more commonly observed chaotic behavior between these two extremes. When we see irregularity we cling to randomness and disorder for explanations. Why should this be so? Why is it that when the ubiquitous irregularity of engineering, physical, biological, and other systems are studied, it is assumed to be random and the whole vast machinery of probability and statistics is applied? Rather recently, however, we have begun to realize that the tools of chaos theory can be applied toward the understanding, manipulation, and control of a variety of systems, with many of the practical applications coming after 1990. To understand why this is true, one must start with a working knowledge of how chaotic systems behave&mdash;profoundly, but sometimes subtly different, from the behavior of random systems.
Design principles and performance analysis of SSCOP: a new ATM adaptation layer protocol
Authors: Thomas R. Henderson
Venue: ACM SIGCOMM Computer Communication Review (1995)

The Service Specific Connection Oriented Protocol (SASCOP) has been approved recently as a new B-ISDN ATM Adaptation Layer (AAL) protocol standard, initially for use in the Signaling ATM Adaptation Layer (SAAL), but also for support of certain types of use data transfer. SSCOP is a new type of protocol, embodying several design principles for high speed link and transport layer protocols. In this paper, the basic operation of SSCOP is described and the SSCOP design is compared with other similar protocols. Next, the relationships between key protocol parameters (protocol window, control message transmission interval) and maximum achievable throughput effieiency are explored. In particular, approximate performance equations are derived for predicting the maximum throughput efficiency of SSCOP basedon the selected environment and parameter eettings. The equations can be used to determine how much buffer capacity and/or what protocol timer settings allow SSCOP to operate at high performance. The analytical results are confirmed through comparison with simulation results. In addition, simulation results illustrate the high throughput performance achievable when using SSCOP in a highly errored or loosy environment.
An introduction to the RESearch Queueing Package for modeling contention systems
Authors: E. A. MacNair, R. F. Gordon
Venue: ACM SIGSIM Simulation Digest (1994)

A queueing network is an important tool for modeling systems where performance is principally affected by contention for resources. Such systems include computer systems, communication networks and manufacturing lines. In order to effectively use queuing networks as performance models, appropriate software is necessary for definition of the networks to be solved, for solution of the networks and for examination of the performance measures obtained.The RESearch Queueing Package (RESQ) and the RESearch Queueing Modeling Environment (RESQME) form a system for constructing, solving and analyzing extended queueing network models. We refer to the class of RESQ networks as "extended" because of characteristics which allow effective representation of system detail. RESQ incorporates a high level language to concisely describe the structure of the model and to specify constraints on the solution. A main feature of the language is the capability to describe models in a hierarchical fashion, allowing an analyst to define submodels to be used analogously to use of macros in programming languages. RESQ also provides a variety of methods for estimating the accuracy of simulation results and for determining simulation run lengths. RESQME is a graphical interface for RESQ.
COMA: an opportunity for building fault-tolerant scalable shared memory multiprocessors
Authors: Christine Morin, Alain Gefflaut, Michel Banâtre, Anne-Marie Kermarrec
Venue: Proceedings of the 23rd annual international symposium on Computer architecture (1996)

Due to the increasing number of their components, Scalable Shared Memory Multiprocessors (SSMMs) have a very high probability of experiencing failures. Tolerating node failures therefore becomes very important for these architectures particularly if they must be used for long-running computations. In this paper, we show that the class of Cache Only Memory Architectures (COMA) are good candidates for building fault-tolerant SSMMs. A backward error recovery strategy can be implemented without significant hardware modification to previously proposed COMA by exploiting their standard replication mechanisms and extending the coherence protocol to transparently manage recovery data. Evaluation of the proposed fault-tolerant COMA is based on execution driven simulations using some of the Splash applications. We show that, for the simulated architecture, the performance degradation caused by fault-tolerance mechanisms varies from 5% in the best case to 35% in the worst case. The standard memory behavior is only slightly perturbed. Moreover, results also show that the proposed scheme preserves the architecture scalability and that the memory overhead remains low for parallel applications using mostly shared data.
Using metrics to evaluate student programs
Authors: Ronald J. Leach
Venue: ACM SIGCSE Bulletin (1995)

Student programs in electronic form can be tested by the instructor against his or her own test data. There are other advantages to electronic submission. We report on the use of software metrics analysis tools to determine "similarities" in student programs. Availability of these tools has virtually eliminated student copying of assignments.
All Nearest Smaller Values on the Hypercube
Authors: Dina Kravets, C. Greg Plaxton
Venue: IEEE Transactions on Parallel and Distributed Systems (1996)

Given a sequence of n elements, the All Nearest Smaller Values (ANSV) problem is to find, for each element in the sequence, the nearest element to the left (right) that is smaller, or to report that no such element exists. Time and work optimal algorithms for this problem are known on all the PRAM models [3], [5] but the running time of the best previous hypercube algorithm [6] is optimal only when the number of processors p satisfies 1 ¿p¿n/((lg3n)(lg lg n)2). In this paper, we prove that any normal hypercube algorithm requires ¿(n) processors to solve the ANSV problem in O(lg n) time, and we present the first normal hypercube ANSV algorithm that is optimal for all values of n and p. We use our ANSV algorithm to give the first O(lg n)-time n-processor normal hypercube algorithms for triangulating a monotone polygon and for constructing a Cartesian tree.
Table-driven implementation of the exponential function in IEEE floating-point arithmetic
Authors: Ping-Tak Peter Tang
Venue: ACM Transactions on Mathematical Software (TOMS) (1989)

Algorithms and implementation details for the exponential function in both single- and double-precision of IEEE 754 arithmetic are presented here. With a table of moderate size, the implementations need only working-precision arithmetic and are provably accurate to within 0.54 ulp as long as the final result does not underflow. When the final result suffers gradual underflow, the error is still no worse than 0.77 ulp.
Numerical Analysis for the Heat Flux in a Mixed Elliptic Problem to Obtain a Discrete Steady-State Two-Phase Stefan Problem
Authors: Domingo Alberto Tarzia
Venue: SIAM Journal on Numerical Analysis (1996)

We consider a material $\Omega \subset {\Bbb R}^n$ which occupies a convex polygonal bounded domain with regular boundary $\Gamma=\Gamma_1\cup \Gamma_2$ (with $\mathop{\Gamma}\limits^{\circ}\hspace*{-2pt}\mathop{}\nolimits_1 \cap\mathop{\Gamma}\limits^{\circ}\hspace*{-2pt}\mathop{}\nolimits_2=\emptyset$) with meas$(\Gamma_1)=|\Gamma_1|>0$ and $|\Gamma_2|>0$. We assume, without loss of generality, that the melting temperature is 0$^{\circ}$C. We apply a temperature $b=$ Const $ > 0$ on $\Gamma_1$ and a heat flux $q=$ Const $> 0$ on $\Gamma_2$. We consider a steady-state heat conduction problem in $\Omega$.We consider a regular triangulation of the domain $\Omega$ with Lagrange triangles of type 1. We study sufficient (and/or necessary) conditions on the heat flux $q$ on $\Gamma_2$ to obtain a change of phase (steady-state, two-phase, discretized Stefan problem) in the corresponding discretized domain, that is, a discrete temperature of nonconstant sign in $\Omega$.
Efficient reduced-order modeling for the transient simulation of three-dimensional interconnect
Authors: Mike Chou, Jacob White
Venue: Proceedings of the 1995 IEEE/ACM international conference on Computer-aided design (1995)

Abstract: Multipole-accelerated surface-volume methods have proved to be very efficient techniques for delay and cross-talk simulation of three-dimensional integrated circuit interconnect. However, to be efficiently combined with transistor circuitry in a SPICE-level simulation, reduced-order models which have accurate low-frequency behavior must be constructed. Asymptotic Waveform Evaluation (AWE) or Pade-via-Lanczos (PVL) algorithms can not be used directly to construct the reduced-order models from the surface-volume formulation, because the formulation generates dense matrices which are too expensive to factor. In this paper we describe a two-level approach to efficiently generating reduced-order models with accurate low frequency behavior. First, reduced-order models which match Taylor series terms at s=/spl infin/ are efficiently generated from the surface-volume formulation using an Arnoldi method, and then these fairly high-order models are used to efficiently construct lower-order models which snatch Taylor series terms at s=0. Examples are given to demonstrate the accuracy of the resultant low-order model.
Collaboration in the small vs. collaboration in the large
Authors: Philip M. Johnson
Venue: ACM SIGOIS Bulletin (1995)

For the past several years, the Collaborative Software Development Laboratory (CSDL) at the University of Hawaii has been pursuing research along two general fronts: the development of computer systems to support group activities (collaborative software), as well as research on the process of developing software in a group setting (collaborative development). Our research projects include: bull; Egret, a client-server system for implementing domain-specific, collaborative, hypertext systems [1, 6, 7, 9]; bull; CSRS, an Egret-based system for software review and quality improvement [2, 10, 11, 12, 8, 6, 7, 9]; bull; AEN, an Egret-based system for collaborative authoring and learning [3]; bull; CLARE, an Egret-based system collaborative learning and review [4, 13, 14, 15]. bull; ICS-WWW, a WWW-based system for exploring community building through electronic means [5].From these experiences, we have be gun to recognize two fundamentally different styles of collaboration and collaborative system, which we term collaboration-in-t he-large and collaboration-in-the-small. Collaboration in the large, embodied by such systems as WWW, scales to thousands or millions of individuals. Such domain-independent scale requires a kind of collaborative "open world assumption": users do not know the answers to such elementary questions as: Who are the other users? What is the set of artifacts in the system? What has changed sinceyesterday? What is interesting to me? Is the information repository structurally consistent? What is user X doing right now?In contrast, the systems b uilt by our lab exploit the possibiliti es of domain-specific, collaboration-in-the- small where a "closed world assumption" holds. In our systems, in contrast to WWW, all of the preceeding questions have answers, at least relative to the domain of discourse embodied in the system. The cost of collaboration in the small is its lack of scalability both technically and socially: it is unlikely that groups of more than 50 or 100 could work together effectively in our systems, or that our system could provide adequate responsiveness to larger groups.
Architectures for cooperative systems
Authors: Brian Hanley
Venue: ACM SIGOIS Bulletin (1995)

The primary perspective which the author brings to this topic comes from working with the design and implementation of high level CASE tools. The interest which I have in software architectures for cooperative systems stems from considering the problem of how to best design a set of templates for the implementation of cooperative systems. There are special considerations to this problem when considered from this additional level of abstraction. One should optimally create a set of templates that can be deployed across many different platforms, for example: PC-Windows, UNIX of various flavors, AS/400. If one is to be able to mix and match all or most of the components across these platforms at will, it is necessary to minimize approaches which are unique to a particular architecture.
The synergetic effect of compiler, architecture, and manual optimizations on the performance of CFD on multiprocessors
Authors: Masayuki Kuba, Constantine D. Polychronopoulos, Kyle Gallivan
Venue: Proceedings of the 1995 ACM/IEEE conference on Supercomputing (CDROM) (1995)

This paper discusses the comprehensive performance profiling, improvement and benchmarking of a Computational Fluid Dynamics code, one of the Grand Challenge applications, on three popular multiprocessors. In the process of analyzing performance we considered language, compiler, architecture, and algorithmic changes and quantified each of them and their incremental contribution to bottom-line performance. We demonstrate that parallelization alone cannot result in significant gains if the granularity of parallel threads and the effect of parallelization on data locality are not taken into account. Unlike benchmarking studies that often focus on the performance or effectiveness of parallelizing compilers on specific loop kernels, we used the entire CFD code to measure the global effectiveness of compilers and parallel architectures. We probed the performance bottlenecks in each case and derived solutions which eliminate or neutralize the performance inhibiting factors. The major conclusion of our work is that overall performance is extremely sensitive to the synergetic effects of compiler optimizations, algorithmic and code tuning, and architectural idiosyncrasies.