ppxscal/embedding_network huggingface dataset:
Evaluating stereo and motion cues for visualizing information nets in three dimensions
Authors: Colin Ware, Glenn Franck
Venue: ACM Transactions on Graphics (TOG) (1996)

This article concerns the benefits of presenting abstract data in 3D. Two experiments show that motion cues combined with stereo viewing can substantially increase the size of the graph that can be preceived. The first experiment was designed to provide quantitiative measurements of how much more (or less) can be understood in 3D than in 2D. The 3D display used was configured so that the image on the monitor was coupled to the user's actual eye positons (and it was updated in real-time as the user moved) as well as bring in stereo. Thus the effect was like a local &ldquo;virtual reality&rdquo; display located in the vicinity of the computer monitor. The results from this study show that head-coupled stereo viewing can increase the size of an abstract graph that can be understood by a factor of three; using stereo alone provided an increase by a factor of 1.6 and head coupling along produced an increase by a factor of 2.2. The second experiment examined a variety of motion cues provided by head-coupled perspective (as in virtual reality displays), head-guided motion and automatic rotation, respectively, both with and without stereo in each case. The results show that structured 3D motion and stereo viewing both help in understanding, but that the kind of motion is not particularly important; all improve performance, and all are more significant than stereo cues. These results provide strong reasons for using advanced 3D graphics for interacting with a large variety of information structures.
Workflow technology: trade-offs for business process re-engineering
Authors: Keith D. Swenson, Kent Irwin
Venue: Proceedings of conference on Organizational computing systems (1995)

The relationship is examined between Business Process Reengineering (BPR), a significant new management trend across all industries, and Workflow Technology a new and rapidly expanding sector of the software market. Since Workflow is a market driven technology, in order to make a meaningful analysis, we start by presenting the current state of the art in workflow technology, as uncovered by our work within the Workflow Management Coalition. Some aspects of workflow are found to be well suited to support BPR, as long as the process being supported meets one of three criteria. Yet other aspects result in serious drawbacks that limit the benefit gained. Some conclusions are made about how workflow technology will have to evolve in order to more fully support the needs of BPR.
Modeling and simulation of self-similar variable bit rate compressed video: a unified approach
Authors: Changcheng Huang, Michael Devetsikiotis, Ioannis Lambadaris, A. Roger Kaye
Venue: Proceedings of the conference on Applications, technologies, architectures, and protocols for computer communication (1995)

Variable bit rate (VBR) compressed video is expected to become one of the major loading factors in high-speed packet networks such as ATM-based B-ISDN. However, recent measurements based on long empirical traces (complete movies) revealed that VBR video traffic possesses self-similar (or fractal) characteristics, meaning that the dependence in the traffic stream lasts much longer than traditional models can capture.In this paper, we present a unified approach which, in addition to accurately modeling the marginal distribution of empirical video records, also models directly both the short and the long-term empirical autocorrelation structures. We also present simulation results using synthetic data and compare with results based on empirical video traces.Furthermore, we extend the application of efficient estimation techniques based on importance sampling that we had used before only for simple fractal processes. We use importance sampling techniques to efficiently estimate low probabilities of packet losses that occur when a multiplexer is fed with synthetic traffic from our self-similar VBR video model.
The accelerated integer GCD algorithm
Authors: Kenneth Weber
Venue: ACM Transactions on Mathematical Software (TOMS) (1995)

Since the greatest common divisor (GCD) of two integers is a basic arithmetic operation used in many mathematical software systems, new algorithms for its computation are of widespread interest. The accelerated integer GCD algorithm discussed here is based on a reduction step proposed by Sorenson (k-ary reduction), coupled with the dmod operation similar to Norton's smod. Some practical limitations of Sorenson's reduction have been eliminated. Worst-case complexity is still O(n2) for n-bit input, but actual implementations given input about 4096 bits long perform over 5.5 times as fast as the binary GCD on one computer architecture having a multiply instruction. Independent research by Jebelean points to the same conclusions.
Fault-Tolerant Features in the HaL Memory Management Unit
Authors: Nirmal R. Saxena, Chih-Wei David Chang, Kevin Dawallu, Jaspal Kohli, Patrick Helland
Venue: IEEE Transactions on Computers (1995)

This paper describes fault-tolerant and error detection features in HaL's memory management unit (MMU). The proposed fault-tolerant features allow recovery from transient errors in the MMU. It is shown that these features were natural choices considering the architectural and implementation constraints in the MMU's design environment. Three concurrent error detection and correction methods employed in address translation and coherence tables in the MMU are described. Virtually-indexed and virtually-tagged cache architecture is exploited to provide an almost fault-secure hardware coherence mechanism in the MMU, with very small performance overhead (less than 0.01% in the instruction throughput). Low overhead linear polynomial codes have been chosen in these designs to minimize both the hardware and software instrumentation impact.Index Terms¿Coherence, concurrent error detection/ correction, linear polynomial codes, translation lookaside buffers, content addressable memory, memory management unit, fault-tolerant computing.
Safe and efficient sharing of persistent objects in Thor
Authors: B. Liskov, A. Adya, M. Castro, S. Ghemawat, R. Gruber, U. Maheshwari, A. C. Myers, M. Day, L. Shrira
Venue: Proceedings of the 1996 ACM SIGMOD international conference on Management of data (1996)

Thor is an object-oriented database system designed for use in a heterogeneous distributed environment. It provides highly-reliable and highly-available persistent storage for objects, and supports safe sharing of these objects by applications written in different programming languages.Safe heterogeneous sharing of long-lived objects requires encapsulation: the system must guarantee that applications interact with objects only by invoking methods. Although safety concerns are important, most object-oriented databases forgo safety to avoid paying the associated performance costs.This paper gives an overview of Thor's design and implementation. We focus on two areas that set Thor apart from other object-oriented databases. First, we discuss safe sharing and techniques for ensuring it; we also discuss ways of improving application performance without sacrificing safety. Second, we describe our approach to cache management at client machines, including a novel adaptive prefetching strategy.The paper presents performance results for Thor, on several OO7 benchmark traversals. The results show that adaptive prefetching is very effective, improving both the elapsed time of traversals and the amount of space used in the client cache. The results also show that the cost of safe sharing can be negligible; thus it is possible to have both safety and high performance.
A reliable multicast framework for light-weight sessions and application level framing
Authors: Sally Floyd, Van Jacobson, Steve McCanne, Ching-Gung Liu, Lixia Zhang
Venue: ACM SIGCOMM Computer Communication Review (1995)

This paper describes SRM (Scalable Reliable Multicast), a reliable multicast framework for application level framing and light-weight sessions. The algorithms of this framework are efficient, robust, and scale well to both very large networks and very large sessions. The framework has been prototyped in wb, a distributed whiteboard application, and has been extensively tested on a global scale with sessions ranging from a few to more than 1000 participants. The paper describes the principles that have guided our design, including the IP multicast group delivery model, an end-to-end, receiver-based model of reliability, and the application level framing protocol model. As with unicast communications, the performance of a reliable multicast delivery algorithm depends on the underlying topology and operational environment. We investigate that dependence via analysis and simulation, and demonstrate an adaptive algorithm that uses the results of previous loss recovery events to adapt the control parameters used for future loss recovery. With the adaptive algorithm, our reliable multicast delivery algorithm provides good performance over a wide range of underlying topologies.
Customer-developer links in software development
Authors: Mark Keil, Erran Carmel
Venue: Communications of the ACM (1995)

Many of the best ideas for new products and product improvements come from the customer or end user of the product [15]. In the software arena, tapping into this source of information requires the establishment of one or more customer-developer links. These links are defined as the techniques and/or channels that allow customers and developers to exchange information.
QUEST: queueing event simulation tool
Authors: Joseph Hugan
Venue: Proceedings of the 27th conference on Winter simulation (1995)

QUEST is a 3D general purpose simulator that uses physical and logical relationships to rapidly model everything from complex manufacturing systems to business process re-engineering (BPR) opportunities. QUEST's flexible, tightly integrated environment allows users to create a single interface where they can build, run, and analyze their systems using familiar terminology and customized output. This tutorial covers the main features of QUEST and its model building approach. An example model is built to demonstrate the discussed features. The integration of QUEST with other Deneb products is discussed.
New Necessary Conditions for the Generalized Problem of Bolza
Authors: P. D. Loewen, R. T. Rockafellar
Venue: SIAM Journal on Control and Optimization (1996)

Problems of optimal control are considered in the neoclassical Bolza format, which centers on states and velocities and relies on nonsmooth analysis. Subgradient versions of the Euler--Lagrange equation and the Hamiltonian equation are shown to be necessary for the optimality of a trajectory, moreover in a newly sharpened form that makes these conditions equivalent to each other. At the same time, the assumptions on the Lagrangian integrand are weakened substantially over what has been required previously in obtaining such conditions.
Support for implementing scheduling algorithms using MESSIAHS
Authors: Steve J. Chapin, Eugene H. Spafford
Venue: Scientific Programming (1994)

The MESSIAHS project is investigating mechanisms that support task placement in heterogeneous, distributed, autonomous systems. MESSIAHS provides a substrate on which scheduling algorithms can be implemented. These mechanisms were designed to support diverse task placement and load balancing algorithms. As part of this work, we have constructed an interface layer to the underlying mechanisms. This includes the MESSIAHS interface language (MIL) and a library of function calls for constructing distributed schedulers. This article gives an overview of MESSIAHS, describes two sample interface layers in detail, and gives example implementations of well-known algorithms from the literature built using these layers.
Activity-driven clock design for low power circuits
Authors: Gustavo E. Téllez, Amir Farrahi, Majid Sarrafzadeh
Venue: Proceedings of the 1995 IEEE/ACM international conference on Computer-aided design (1995)

In this paper we investigate activity-driven clock trees to reduce the dynamic power consumption of synchronous digital CMOS circuits. Sections of an activity-driven clock tree can be turned on/off by gating the clock signals during the active/idle times of the clocked elements. We propose a method of obtaining the switching activity patterns of the clocked circuits during the high level design process. We formulate three novel activity-driven problems. The objective of these problems is to minimize system's dynamic power consumption. We propose an approximation algorithm based on recursive matching to solve the clock tree construction problem. We solve the gate insertion problems with an exact algorithm employing the dynamic programming paradigm. Finally, we present experimental results that verify the effectiveness of our approach. Our work in this paper is a step in understanding how high level decisions (e.g. behavioral design) can affect a low level design (e.g. clock design).
Implementation of the data-flow synchronous language SIGNAL
Authors: Pascalin Amagbégnon, Loïc Besnard, Paul Le Guernic
Venue: Proceedings of the ACM SIGPLAN 1995 conference on Programming language design and implementation (1995)

This paper presents the techniques used for the compilation of the data-flow, synchronous language SIGNAL. The key feature of the compiler is that it performs formal calculus on systems of boolean equations. The originality of the implementation of the compiler lies in the use of a tree structure to solve the equations.
Mapping the discourse of HCI researchers with citation analysis
Authors: Thomas W. Dillon
Venue: ACM SIGCHI Bulletin (1995)

This paper observes the development of human-computer interaction as a research discipline from 1991 to 1993. From a citation analysis of three volumes of three journals, the field of human computer interaction is identified as emerging from a supporting base of four fields: computer science, information systems, psychology, and human factors/ ergonomics. Results of this analysis support the proposition that human-computer interaction is emerging as a distinct field of study.
Nonlinear Boundary Control of Semilinear Parabolic Systems
Authors: N. U. Ahmed, X. Xiang
Venue: SIAM Journal on Control and Optimization (1996)

Nonlinear boundary control problems for a class of semilinear parabolic systems are considered, from the point of view of semigroup theory. The method is based on some recent general results on parabolic evolution equations with nonlinear boundary conditions. Existence of optimal (boundary) controls is proved using the theory of measurable selections and the Cesari property for multifunctions. Three results are presented covering relaxed controls and controls with state constraints. This generalizes, in a substantial way, existing results on linear boundary control problems [M. C. Delfour and M. Sorine, Control of Distributed Parameter Systems, Pergamon Press, Oxford, 1983, pp. 87--90], [I. Lasiecka, Appl. Math. Optim., 6 (1980), pp. 287--383], [P. Acquistapace, et al., SIAM J. Control Optim., 29 (1991), pp. 89--118]. The result presented can be further extended to differential inclusions. Two examples are presented for illustration.
Tree Approximations to Markov Random Fields
Authors: Chi-hsin Wu, Peter C. Doerschuk
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1995)

Methods for approximately computing the marginal probability mass functions and means of a Markov random field (MRF) by approximating the lattice by a tree are described. Applied to the a posteriori MRF these methods solve Bayesian spatial pattern classification and image restoration problems. The methods are described, several theoretical results concerning fixed-point problems are proven, and four numerical examples are presented, including comparison with optimal estimators and the Iterated Conditional Mode estimator and including two agricultural optical remote sensing problems.
Polygon Posets and the Weak Order of Coxeter Groups
Authors: Kimmo Eriksson
Venue: Journal of Algebraic Combinatorics: An International Journal (1995)

We explore the connection between polygon posets, which is a class of ranked posets with an edge-labeling which satisfies certain &lsquo;polygon properties&rsquo;, and the weak order of Coxeter groups. We show that every polygon poset is isomorphic to a join ideal in the weak order, and for Coxeter groups where no pair of generators have infinite order the converse is also true.The class of polygon posets is seen to include the class of generalized quotients defined by Bj&ouml;rner and Wachs, while itself being included in the class of alternative generalized quotients also considered by these authors. By studying polygon posets we are then able to answer an open question about common properties of these two classes.
ObjectMath&mdash;an object-oriented language and environment for symbolic and numerical processing in scientific computing
Authors: Lars Viklund, Peter Fritzson
Venue: Scientific Programming (1995)

ObjectMath is a language for scientific computing that integrates object-oriented constructs with features for symbolic and numerical computation. Using ObjectMath, complex mathematical models may be implemented in a natural way. The ObjectMath programming environment provides tools for generating efficient numerical code from such models. Symbolic computation is used to rewrite and simplify equations before code is generated. One novelty of the ObjectMath approach is that it provides a comman language and an integrated environment for this kind of mixed symbolic/numerical computation. The motivation for this work is the current low-level state of the art in programming for scientific computing. Much numerical software is still being developed the traditional way in Fortran. This is especially true in application areas such as machine elements analysis, where complex nonlinear problems are the norm. We believe that tools like ObjectMath can increase productivity and quality, thus enabling users to solve problems that are too complex to handle with traditional tools.
Parallelism in Lisp
Authors: Guy L. Steele,  Jr.
Venue: ACM SIGPLAN Lisp Pointers (1995)

Maybe not as hot a topic in computer architecture as it used to be, but still of considerable interest, is parallelism. How do you make a faster computer? Just strap 20 or 200 or 2000 processors together? As we have learned, the architectural and hardware difficulties are immense (How do you connect them? A shared bus? A network? Is there a single system clock or many clocks?), and after these have been solved there remains the matter of programming.
Dynamic load balancing of a multi-cluster simulator on a network of workstations
Authors: Rolf Schlagenhaft, Martin Ruhwandl, Christian Sporrer, Herbert Bauer
Venue: ACM SIGSIM Simulation Digest (1995)

Performance of Time Warp simulation systems are often measured on exclusively available parallel computing resources. In distributed systems exclusive use is normally not feasible. Instead, due to the multi-tasking operating systems, many users share the workstations and their availability for parallel simulation purposes varies extensively. Time Warp has been found to be very sensitive to variations in available processing power. This paper presents two methods for a Time Warp VLSI simulation system to reduce the negative effect of a non-ideal environment on the execution of parallel simulations. A dynamic load balancing algorithm which adapts to the change of available processing power is presented. This mechanism, together with a multi-cluster partitioning technique significantly improve the performance of Time Warp based simulation systems on heterogeneous computing resource.
Simultaneous multithreading: maximizing on-chip parallelism
Authors: Dean M. Tullsen, Susan J. Eggers, Henry M. Levy
Venue: Proceedings of the 22nd annual international symposium on Computer architecture (1995)

This paper examines simultaneous multithreading, a technique permitting several independent threads to issue instructions to a superscalar's multiple functional units in a single cycle. We present several models of simultaneous multithreading and compare them with alternative organizations: a wide superscalar, a fine-grain multithreaded processor, and single-chip, multiple-issue multiprocessing architectures. Our results show that both (single-threaded) superscalar and fine-grain multithreaded architectures are limited their ability to utilize the resources of a wide-issue processor. Simultaneous multithreading has the potential to achieve 4 times the throughput of a superscalar, and double that of fine-grain multithreading. We evaluate several cache configurations made possible by this type of organization and evaluate tradeoffs between them. We also show that simultaneous multithreading is an attractive alternative to single-chip multiprocessors; simultaneous multithreaded processors with a variety of organizations outperform corresponding conventional multiprocessors with similar execution resources.While simultaneous multithreading has excellent potential to increase processor utilization, it can add substantial complexity to the design. We examine many of these complexities and evaluate alternative organizations in the design space.
Dynamic Broadcasting in Parallel Computing
Authors: Emmanouel A. Varvarigos, Dimitri P. Bertsekas
Venue: IEEE Transactions on Parallel and Distributed Systems (1995)

We consider the problem where broadcast requests are dynamically generated at random time instants at each node of a multiprocessor network. In particular, in our model packets arrive at each node of a network according to a Poisson process, and each packet has to be broadcast to all the other nodes. We propose an on-line, distributed routing scheme to execute the broadcasts in this dynamic environment. Our scheme consists of repeated execution of a partial multinode broadcast task, which is a static communication task where any $M \leq N$ arbitrary nodes of an $N$-processor network broadcast a packet to all the other nodes. The dynamic broadcasting scheme that we propose can be used in any topology, regular or not, for which partial multinode broadcast algorithms with certain properties can be found. We derive such an algorithm and we analyze the corresponding dynamic broadcasting scheme for the hypercube network. We show that its stability region tends to the maximum possible as the number of nodes of the hypercube tends to infinity. Furthermore, for any fixed load in the stability region, the average delay is of the order of the diameter of the hypercube. Our analysis does not use any approximating assumptions.Index Terms¿Dynamic broadcasting, queuing systems, average delay, stability region, hypercubes.
Supporting unstructured workflow activities in the Bramble ICN system
Authors: Richard Blumenthal, Gary J. Nutt
Venue: Proceedings of conference on Organizational computing systems (1995)

Workflow systems have been proposed as a means for automating business procedures. While growing in popularity, many fundamental problems, such as supporting unstructured office activities, still remain before this technology will be especially useful in the office. This paper examines difficulties associated with handling unstructured office activities and argues that it is both necessary and possible for workflow technology to better support office workers who perform these activities. The approach illustrated in this paper advocates reducing the rigidity of the workflow system's computational model, which, in turn, requires the system to better support the contextual information needs of the workers performing the unstructured activities.