ppxscal/embedding_network huggingface dataset:
Advanced Array Optimizations for High Performance Functional Languages
Authors: David C. Cann, Paraskevas Evripidou
Venue: IEEE Transactions on Parallel and Distributed Systems (1995)

In this paper, we discuss and evaluate three optimizations for reducing memory management overhead and data copying costs in SISAL 1.2 programs that build arrays. The first, called framework preconstruction, eliminates superfluous allocate-deallocate sequences in cyclic computations. The second, called aggregate storage subsumption, reduces the management overhead for compound array components. The third, called predictive storage preallocation, eliminates superfluous data copying in filtered array constructions and simplifies their parallelization. We have added all three optimizations to the Optimizing SISAL Compiler with rewarding improvements in SISAL program performance on vector-parallel machines such as those built by Cray Computer Corporation, Convex, and Cray Research.Index Terms¿Functional languages, parallel computing, vector computing, imperative languages, copy elimination, storage optimizations, arrays.
Coping with RC(L) interconnect design headaches
Authors: Lawrence Pileggi
Venue: Proceedings of the 1995 IEEE/ACM international conference on Computer-aided design (1995)

Physical interconnect effects have a dominant impact on today's deep submicron IC designs. In this tutorial paper we will describe the technology trends which have brought about this interconnect dominance, then consider some of the modeling and analysis approximations available for both pre- and post-layout interconnect design. This coverage will not be an exhaustive summary, but one that is primarily focused on moment-based analysis techniques, from the Elmore delay, to the more recent advances in moment-matching approximations, and the corresponding nonlinear driver/load interfaces. Future modeling, analysis, and design challenges will be considered throughout this paper.
Simulation modeling within workflow technology
Authors: John A. Miller, Amit P. Sheth, Krys J. Kochut, Xuzhong Wang, Arun Murugan
Venue: Proceedings of the 27th conference on Winter simulation (1995)

This paper presents an approach for integrating simulation modeling and analysis capabilities within the workflow management system (WFMS) being developed in the Large Scale Distributed Information Systems (LSDIS) Lab at the University of Georgia. Simulation modeling can be used for studying the efficiency of workflow designs as well as studying the general performance and reliability of WFMSs. We also discuss the importance of using sophisticated monitoring and animation capabilities, and the use of workflow management technology to advance simulation technology itself. Finally, we demonstrate a sample simulation where tasks and task managers are simulated.
Efficient Nonblocking Switching Networks for Interprocessor Communications in Multiprocessor Systems
Authors: Fong-Chih Shao, A. Yavuz Oruç
Venue: IEEE Transactions on Parallel and Distributed Systems (1995)

The performance of a multiprocessor system depends heavily on its ability to provide conflict free paths among its processors. In this paper, we explore the possibility of using a nonblocking network with $O(N \log N)$ edges (crosspoints) to interconnect the processors of an $N$ processor system. We combine Bassalygo and Pinsker's implicit design of strictly nonblocking networks with an explicit construction of expanders to obtain a strictly nonblocking network with $-765.18 N + 352.8 N \log N$ edges and $2+\log (N/5)$ depth. We present an efficient parallel algorithm for routing connection requests on this network and implement it on three parallel processor topologies. The implementation on a parallel processor whose processing elements are interconnected as in the Bassalygo¿Pinsker network requires $O(N\log N)$ processing elements, $O(N\log N)$ interprocessor links and it takes $O(\log N)$ steps to route any single connection request where each step involves a small number ($\approx$72) of bit-level operations. A contracted or folded version of the same implementation reduces the processing element count to $O(N)$ without increasing the link count or the routing time. Finally, we establish that the same algorithm takes $O(\log^3 N)$ steps on a perfect shuffle processor with $O(N)$ processing elements. These results improve the crosspoint, depth and routing time complexities of the previously reported strictly nonblocking networks.Index Terms¿Bassalygo¿Pinsker network, Clos network, Cantor network, extensive graph, expander, parallel routing algorithm, strictly nonblocking network.
Towards an active network architecture
Authors: David L. Tennenhouse, David J. Wetherall
Venue: ACM SIGCOMM Computer Communication Review (1996)

Active networks allow their users to inject customized programs into the nodes of the network. An extreme case, in which we are most interested, replaces packets with "capsules" - program fragments that are executed at each network router/switch they traverse.Active architectures permit a massive increase in the sophistication of the computation that is performed within the network. They will enable new applications, especially those based on application-specific multicast, information fusion, and other services that leverage network-based computation and storage. Furthermore, they will accelerate the pace of innovation by decoupling network services from the underlying hardware and allowing new services to be loaded into the infrastructure on demand.In this paper, we describe our vision of an active network architecture, outline our approach to its design, and survey the technologies that can be brought to bear on its implementation. We propose that the research community mount a joint effort to develop and deploy a wide area ActiveNet.
Algorithm 651: Algorithm HFFT–high-order fast-direct solution of the Helmholtz equation
Authors: Ronald F. Boisvert
Venue: ACM Transactions on Mathematical Software (TOMS) (1987)

HFFT is a software package for solving the Helmholtz equation on bounded two- and three-dimensional rectangular domains with Dirichlet, Neumann, or periodic boundary conditions. The software is the result of combining new fourth-order accurate compact finite difference (HODIE) discretizations and a fast-direct solution technique (the Fourier method). In this paper we briefly describe the user interface to HFFT and present an example of its usage and several details of its implementation.
A hybrid execution model for fine-grained languages on distributed memory multicomputers
Authors: John Plevyak, Vijay Karamcheti, Xingbin Zhang, Andrew A. Chien
Venue: Proceedings of the 1995 ACM/IEEE conference on Supercomputing (CDROM) (1995)

While fine-grained concurrent languages can naturally capture concurrency in many irregular and dynamic problems, their flexibility has generally resulted in poor execution effciency. In such languages the computation consists of many small threads which are created dynamically and synchronized implicitly. In order to minimize the overhead of these operations, we propose a hybrid execution model which dynamically adapts to runtime data layout, providing both sequential efficiency and low overhead parallel execution. This model uses separately optimized sequential and parallel versions of code. Sequential efficiency is obtained by dynamically coalescing threads via stack-based execution and parallel efficiency through latency hiding and cheap synchronization using heap-allocated activation frames. Novel aspects of the stack mechanism include handling return values for futures and executing forwarded messages (the responsibility to reply is passed along, like call/cc in Scheme) on the stack. In addition, the hybrid execution model is expressed entirely in C, and therefore is easily portable to many systems. Experiments with function-call intensive programs show that this model achieves sequential efficiency comparable to C programs. Experiments with regular and irregular application kernels on the CM5 and T3D demonstrate that it can yield 1.5to 3 times better performance than code optimized for parallel execution alone.
Exponential bounds for the waiting time distribution in Markovian queues, with applications to TES/GI/1 systems
Authors: Youjian Fang, Michael Devetsikiotis, Ioannis Lambadaris, A. Roger Kaye
Venue: Proceedings of the 1995 ACM SIGMETRICS joint international conference on Measurement and modeling of computer systems (1995)

Several services to be supported by emerging high-speed networks are expected to result in highly bursty (autocorrelated) traffic streams. A typical example is variable bit-rate (VBR) compressed video. Therefore, traffic modeling and performance evaluation techniques geared towards autocorrelated streams are extremely important for the design of practical networks.The TES (Transform - Expand - Sample) technique has emerged as a general methodology for modeling autocorrelated random processes with arbitrary marginal distributions. Because of their generality and practical applicability, TES models can be readily used to accurately characterize bursty traffic streams in ATM networks.Although TES models can be easily implemented for simulation studies, the need still exists for analytical results on the performance of queueing systems driven by autocorrelated traffic. Of particular interest are the tails of the waiting time distribution in queues driven by TES-modeled bursty traffic. Such tail probabilities, when they become exceedingly small, may be difficult to obtain via conventional simulation.In order to extend existing results, based on Large Deviations theory, to TES processes, the main difficulty is posed by the continuous state-space of the TES time-series. In this paper, we develop a general result concerning exponential bounds for the waiting time under continuous state-space Markov arrivals. We apply this result to TES/GI/1 queues, show numerical examples, and compare our bound with simulation results. Accurate estimates of extremely low probabilities are obtained by employing fast simulation techniques based on importance sampling.
Models and languages for component description and reuse
Authors: Ben Whittle
Venue: ACM SIGSOFT Software Engineering Notes (1995)

This paper brings together the current research on reusable component models and component description languages for reuse. The paper contains a description and comparison of the 3C and REBOOT component models. The importance and further development of the 3C model is discussed. The component description language field is surveyed, and an introduction is given to the languages LIL, ACT TWO, Pi;, Meld, CDL, CIDER, LILEANNA, and RESOLVE. All of these languages are aimed at describing reusable components in the design stages of development. Criteria for examining component description languages are introduced and used as the basis of a comparison of the languages. The paper concludes with suggestions for the convergence of these developments, and suggestions for further work in this field.
Calculating normalization constants of closed queueing networks by numerically inverting their generating functions
Authors: Gagan L. Choudhury, Kin K. Leung, Ward Whitt
Venue: Journal of the ACM (JACM) (1995)

A new algorithm is developed for calculating normalization constants (partition functions) and moments of product-form steady-state distributions of closed queuing networks and related models. The essential idea is to numerically invert the generating function of the normalization constant and related generating functions appearing in expressions for the moments. It is known that the generating function of the normalization constant often has a remarkably simple form, but numerical inversion evidently has not been considered before. For p-dimensional transforms, as occur with queuing networks having p closed chains, the algorithm recursively performs p one-dimensional inversions. The required computation grows exponentially in the dimension, but the dimension can often be reduced by exploiting conditional decomposition based on special structure. For large populations, the inversion algorithm is made more efficient by computing large sums using Euler summation. The inversion algorithm also has a very low storage requirement. A key ingredient in the inversion algorithm is scaling. An effective static scaling is developed for multichain closed queuing networks with only single-server and (optionally) infinite-server queues. An important feature of the inversion algorithm is a self-contained accuracy check, which allows the results to be verified in the absence of alternative algorithms.
Creating simulation runtimes for profit
Authors: Cliff B. King
Venue: Proceedings of the 27th conference on Winter simulation (1995)

The creation of runtimes in the simulation industry is fast becoming a profitable venture for many business consultants. The majority of small companies lack the expertise and the resources to build their own simulation model. Under these circumstances, it is in the company's best interest to hire an outside consultant. The consultant develops a runtime custom made to meet the needs of the client. Now the client has a powerful tool that they can use as part of their ongoing decision making. The consultant who completes a simulation project, shows the results, gives a few suggestions, and then leaves; deprives the client of the real benefits of simulation; that is, dynamic decision making. On the other hand, the consultant who, in addition to providing the usual consulting services, develops a simulation runtime for the client to use as future decisions have to be made, greatly enhances the overall consulting service. As the effort required to generate simulation runtimes decreases, more consultants will start using them in their practice, and more people will begin using simulation in their business. With proper training, and a well built simulation runtime, everyone from plant managers to accountants can take advantage of simulation for what it is-a decision making tool.
On Linear Recognition of Tree-Width at Most Four
Authors: Daniel P. Sanders
Venue: SIAM Journal on Discrete Mathematics (1996)

A graph $G$ has tree-width at most $k$ if the vertices of $G$ can be decomposed into a tree-like structure of sets of vertices, each set having cardinality at most $k+1$. An alternate definition of tree-width is stated in terms of a $k$-elimination sequence, which is an order to eliminate the vertices of the graph such that each vertex, at the time it is eliminated from the graph, has degree at most $k$. Arnborg and Proskurowski showed that if a graph has tree-width at most a fixed $k$, then many NP-hard problems can be solved in linear time, provided this $k$-elimination sequence is part of the input. These algorithms are very efficient for small $k$, such as 2, 3, or 4, but may be impractical for large $k$ as they depend exponentially on $k$. A reduction process is developed, and reductions are shown that can be applied to a graph of tree-width at most four without increasing its tree-width. Further, each graph of tree-width at most four contains one of these reductions. The reductions are then used in a linear-time algorithm that generates a 4-elimination sequence, if one exists.
A query language for multidimensional arrays: design, implementation, and optimization techniques
Authors: Leonid Libkin, Rona Machlin, Limsoon Wong
Venue: Proceedings of the 1996 ACM SIGMOD international conference on Management of data (1996)

While much recent research has focussed on extending databases beyond the traditional relational model, relatively little has been done to develop database tools for querying data organized in (multidimensional) arrays. The scientific computing community has made little use of available database technology. Instead, multidimensional scientific data is typically stored in local files conforming to various data exchange formats and queried via specialized access libraries tied in to general purpose programming languages.To allow such data to be queried using known database techniques, we design and implement a query language for multidimensional arrays. Our main design decision is to treat arrays as functions from index sets to values rather than as collection types. This leads to clean syntax and semantics as well as simple but powerful optimization rules.We present a calculus for arrays that extends standard calculi for complex objects. We derive a higher-level comprehension style query language based on this calculus and describe its implementation, including a data driver for the NetCDF data exchange format. Next, we explore some optimization rules obtained from the equational laws of our core calculus. Finally, we study the expressiveness of our calculus and prove that it essentially corresponds to adding ranking to a query language for complex objects.
Improving round-trip time estimates in reliable transport protocols
Authors: Phil Karn, Craig Partridge
Venue: ACM SIGCOMM Computer Communication Review (1995)

As a reliable, end-to-end transport protocol, the ARPA Transmission Control Protocol (TCP) uses positive acknowledgements and retransmission to guarantee delivery. TCP implementations are expected to measure and adapt to changing network propagation delays so that its retransmission behavior balances user throughput and network efficiency. However, TCP suffers from a problem we call retransmission ambiguity: when an acknowledgment arrives for a segment that has been retransmitted, there is no indication which transmission is being acknowledged. Many existing TCP implementations do not handle this problem correctly.This paper reviews the various approaches to retransmission and presents a novel and effective approach to the retransmission ambiguity problem.
A Multiple-Sequence Generator Based on Inverted Nonlinear Autonomous Machines
Authors: Chung-Len Lee, Meng-Lieh Sheu
Venue: IEEE Transactions on Computers (1996)

A new multiple-sequence generator scheme to generate a set of deterministic ordered sequence of patterns followed by random patterns is presented in this paper. This scheme is based on an inverted nonlinear autonomous machine which utilizes a two-dimension-like LFSR with nonlinear inverters. A systematic procedure is also presented to obtain the autonomous machine which is more regular in the structure and utilizes less hardware. The generated deterministic sequence of patterns, which may have ordered and repeated patterns, and the random patterns are applicable to sequential circuit testing.
Predicting application behavior in large scale shared-memory multiprocessors
Authors: Karim Harzallah, Kenneth C. Sevcik
Venue: Proceedings of the 1995 ACM/IEEE conference on Supercomputing (CDROM) (1995)

In this paper we present an analytical-based framework for parallel program performance prediction. The main thrust of this work is to provide a means for treating realistic applications within a single unified framework. Our approach is based upon the specification of a set of non-linear equations which describe the application, processor configuration, network and memory operations. These equations are solved iteratively since the application execution rate depends on the communication latencies. The iterative solution technique is found to be efficient as it typically requires only few iterations to reach convergence. Our modeling methodology achieves a good balance between abstraction and accuracy. This is attained by accounting for both time and space dimensions of memory references, while maintaining a simple description of the workload. We demonstrate both the practicality and the accuracy of our approach by comparing predicted results with measurements taken on a commercial multiprocessor system. We found the model to be faithful in reflecting changes in processor speed, and changes in the number and placement of allocated processors.
Computing multivariable Taylor series to arbitrary order
Authors: Richard D. Neidinger
Venue: ACM SIGAPL APL Quote Quad (1995)

Automatic differentiation, manipulating numerical vectors of coefficients, is the efficient way to compute multivariable Taylor series. This does not require symbolic differentiation or numerical approximation but uses exact formulas applied to numerical arrays. Arrays of Taylor series coefficients of any elementary function can be built-up, as the array for each component (combination or function) is a combination of its argument arrays. The functions TIMES and EXP display the algorithmic ideas that enable all of the other standard functions. We study the interesting recursive formulas for these combinations, the resulting algorithms, and the implementation in APL. To handle all coefficients in n variables up to order m, the arrays are hyper-pyramid data structures, considered conceptually as n-dimensional but implemented as one-dimensional arrays. Unlike previous work, this implementation does not require huge arrays for binomial coefficients and indirect referencing. This APL*PLUS III implementation loops through one nested reference array and takes sub-arrays from another for a practical solution to this problem that can make tremendous demands on time and space.
APPlaUSE: A&barbelow;rea and p&barbelow;erformance optimization in a u&barbelow;nified placement and s&barbelow;ynthesis e&barbelow;nvironment
Authors: Elof Frank, Thomas Lengauer
Venue: Proceedings of the 1995 IEEE/ACM international conference on Computer-aided design (1995)

We present a new methodology for \hls, which incorporates placement in an early phase of the synthesis process. This placement, prior to interconnect and storage allocation, allows for early and accurate estimates on area and net length. These cost factors are critical for the quality of the chip. The system has been implemented and extensive tests verify the estimates to be accurate.
TeamBox: an exploration of collaborative interoperability
Authors: Munir Mandviwalla, Peter Grillo
Venue: Proceedings of conference on Organizational computing systems (1995)

Given that teams will tend to use a combination of generic groupware and individual applications, there is a need to address issues of interoperability. However, traditional system interoperability that focuses on making data and applications more accessible may not suffice. In collaborative work, the creating and acting on knowledge is inter-related. Collaborative interoperability should support the sharing and coordination of the knowledge represented by the relationships and context of the data. The requirements and dimensions of collaborative interoperability are outlined. The concept of a &ldquo;collaborative transaction&rdquo; is proposed as a knowledge representation and coordination scheme. The TeamBox design architecture is introduced. The feasibility of the architecture is illustrated by the description of a working prototype.
The stage one Turing test as an artificial intelligence class exercise
Authors: Nancy Lynn Tinkham, Darren F. Provine
Venue: ACM SIGART Bulletin (1995)

This paper describes an implementation of the man-woman Turing test as a class exercise in an artificial intelligence course. The exercise helps students to understand more clearly the difficulties and challenges involved in designing an artificially intelligent computer to pass the more famous person-computer Turing test.