ppxscal/embedding_network huggingface dataset:
Design and performance of special purpose hardware for time warp
Authors: R. M. Fujimoto, J.-J. Tsai, G. Gopalakrishnan
Venue: Proceedings of the 15th Annual International Symposium on Computer architecture (1988)

A special purpose simulation engine based on the Time Warp mechanism is proposed to attack large-scale discrete event simulation problems. A key component of this engine is the rollback chip, a hardware component that efficiently implements state saving and rollback functions in Time Warp. The algorithms implemented by the rollback chip are described, as well as mechanisms that allow efficient implementation. Results of simulation studies are presented that show that the rollback chip can virtually eliminate the state saving overhead that plagues current software implementations of Time Warp.
An Adaptive Reduction Procedure for the Piecewise Linear Approximation of Digitized Curves
Authors: C.-S. Fahn, J.-F. Wang, J.-Y. Lee
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1989)

A new algorithm is presented for the piecewise linear approximation of two-dimensional digitized curves against a square grid. The algorithm utilizes an adaptive reduction procedure in two approximation phases to select the critical points of a digitized curve such that the deviation, from the digitized curve to its final approximated curve, is bounded by a uniform error tolerance. The time complexity of this algorithm is O(m/sup 2/) rather than O(n/sup 2/) on the theoretical plane. In the experiments of fixing the initial and the final processing points, the performance of the algorithm has been compared to those of three prominent other algorithms regarding the required number of critical points and the total execution time of the program. Of the four algorithms compared, the present algorithm consistently has the shortest execution time of the program, and it tends most to require as few critical points as the optimum algorithm that was tested.
On allocating subcubes in a hypercube multiprocessor
Authors: S. Dutt, J. P. Hayes
Venue: Proceedings of the third conference on Hypercube concurrent computers and applications: Architecture, software, computer systems, and general issues - Volume 1 (1988)

In hypercube computers that support a multiuser environment, it is important for the operating system to be able to allocate subcubes of different dimensions. Previously proposed subcube allocation schemes, such as the buddy strategy, may fragment the hypercube excessively. We present a precise characterization of the subcube allocation problem and develop a general methodology to solve it. New subcube allocation and coalescing algorithms are described that have the goal of minimizing fragmentation. The concept of a maximal set of subcubes (MSS), which is useful in making allocations that result in a tightly packed hypercube, is introduced. The problems of allocating subcubes and of forming an MSS are formulated as decision problems, and shown to be NP-hard. Optimal algorithms for allocating subcubes and for forming an MSS are given. We suggest a heuristic procedure for efficiently coalescing a released cube with the existing free cubes. Finally, we present simulation results comparing several different allocation and coalescing strategies, which show that our methods provide a marked performance improvement over previous techniques.
Knowledge acquisition from repertory grids using a logic of confirmation
Authors: K. Ford, F. Petry
Venue: Issue 108 (April 1989) (1989)

This research involves a continuing effort aimed at the development and unification of the prerequisite underlying theoretical foundations for an adequate approach to knowledge elicitation from repertory grid data. The repertory grid is a sorting test in which a list of elements are judged based on a set of constructs, essentially mapping elements onto constructs. Thus knowledge elicitation is performed by the expert's assigning of ratings to elements on the given constructs. The repertory grid is based on the personal construct psychology of Kelly. This theory assumes that people typically use cognitive dimensions - termed constructs - to evaluate their experience where each construct represents a single bipolar distinction.
Resource management in large distributed systems
Authors: Andrzej Goscinski, Mirion Bearman
Venue: ACM SIGOPS Operating Systems Review (1990)

In this paper, we propose that a resource management system for large distributed systems should have two levels --- a lower one, responsible for export and allocation of resources in local distributed systems, and an upper one, which manages special resources/services that are not provided locally. For a local environment, load balancing (implementing export and allocation of computational resources) is realized in a distributed way; and management of peripheral resources is developed based on a name server, which can be centralized, or distributed and replicated. The upper level has a centralized resource management center, which is responsible for export and allocation of both peripheral and computational resources. It contains two parts: a name server, which stores attributed names of all shareable resources and a resource manager, which allocates resources to requesting users of a large distributed system. Communication between the resource management center and the local systems is facilitated through integrating modules. This system is now designed based on the RHODOS distributed operating system.
Teaching the abstract data type in CS2
Authors: Joseph E. Lang, Robert K. Maruyama
Venue: ACM SIGCSE Bulletin (1989)

Teaching the abstract data type in CS2 is made difficult by the fact that the topic is intertwined with issues of language support, dynamic data structures and implementation techniques for dynamic data structures. When we switched to Ada to teach CS2, details of the language support for data abstraction caused us to restructure the CS2 course. By pushing the topic of the abstract data type toward the beginning of the course, we have found that it is covered more successfully.
Human computer interaction group, University of York, U.K. (lab review)
Authors: Michael Harrison, Andrew Monk
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems: Empowering people (1990)

Staff in the Departments of Computer Science and Psychology at the University of York have been cooperating in interdisciplinary research since 1983. The mainstream of York's approach is to apply theory developed in these parent disciplines to HCI design. Our goal is to integrate formal and empirical methods. By formal methods we mean mathematical models that are capable of capturing properties of a user interface. By empirical methods we mean the observation and measurement of user behaviour. Integration of these two approaches is achieved by an iterative design process in which formal models are successively refined by testing their predictions against the results of user trials.
Experimentally Characterizing the Behavior of Multiprocessor Memory Systems: A Case Study
Authors: K. Gallivan, D. Gannon, W. Jalby, A. Malony, H. Wijshoff
Venue: IEEE Transactions on Software Engineering (1990)

It is demonstrated how the behavior of a cache-based multi-vector-processor memory system can be systematically characterized and its performance experimentally correlated with key features of the address stream. The approach is based on the definition of a family of parameterized kernels used to explore specific aspects of the memory system's performance. The empirical results from this kernel suite provide the data from which architectural or algorithmic characteristics can be studied. The results of applying the approach to an Alliant FX/8 are presented and evaluated.
Strategies for Supporting Application Portability
Authors: James D. Mooney
Venue: Computer (1990)

A range of system-design strategies that can be used to support portability and the ways in which these strategies have been employed by past and present systems are examined. The strategies are grouped into three categories: (1) strategies that maintain identical execution-time interfaces by porting system components that form the interface, (2) strategies that maintain identical or nearly identical interfaces for different system components by adhering to appropriate standards, and (3) strategies that assist in the adaptation of programs to a target environment. The principal emphasis is on operating-system issues. User interface portability, dynamic portability in a network, and international exchange of programs are briefly considered.
A syntax and semantics for set-oriented production rules in relational database systems
Authors: J. Widom, S. J. Finkelstein
Venue: ACM SIGMOD Record (1989)

We propose incorporating a production rules facility into a relational database system. Such a facility allows definition of database operations that are automatically executed whenever certain conditions are met. In keeping with the set-oriented approach of relational data manipulation languages, our production rules are also set-oriented&mdash;they are triggered by sets of changes to the database and may consequently perform sets of changes. The condition and action parts of our production rules may refer to the current state of the database as well as to the sets of changes triggering the rules. We define a syntax for production rule definition as an extension to SQL. A model of system behavior is used to give an exact semantics for production rule execution, taking into account externally-generated operations, self-triggering rules, and simultaneous triggering of multiple rules. Due to space constraints, some details and discussion are omitted, and only a few examples are included. See [19] for a more extensive description.
CASE environments for design automation
Authors: A. J. Wasserman
Venue: Proceedings of the 26th ACM/IEEE Design Automation Conference (1989)

This paper gives an introduction to important issues of software engineering and computer-aided software engineering (CASE), focusing on the necessary qualities for a CASE environment. These characteristics are then related to the needs of design automation, showing some of the analogies between CAD and CASE. Finally, the paper describes some properties of the Software through Pictures integrated CASE environment and shows how that environment provides those qualities.
A user interface toolkit based on graphical objects and constraints
Authors: Pedro Szekely, Brad Myers
Venue: ACM SIGPLAN Notices (1988)

One of the most difficult aspects of creating graphical, direct manipulation user interfaces is managing the relationships between the graphical objects on the screen and the application data structures that they represent. Coral (Constraint-based Object-oriented Relations And Language) is a new user interface toolkit under development that uses efficiently-implemented constraints to support these relationships. Using Coral, user interface designers can construct interaction techniques such as menus and scroll bars. More importantly, Coral makes it easy to construct direct-manipulation user interfaces specialized to particular applications. Unlike previous constraint-based toolkits, Coral supports defining constraints in the abstract, and then applying them to different object instances. In addition, it provides iteration constructs where lists of items (such as those used in menus) can be constrained as a group. Coral has two interfaces: a declarative interface that provides a convenient way to specify the desired constraints, and a procedural interface that will allow a graphical user interface management system (UIMS) to automatically create Coral calls.
Non-local path integral Monte Carlo on the hypercube
Authors: D. Callahan
Venue: Proceedings of the third conference on Hypercube concurrent computers and applications - Volume 2 (1989)

Some interesting physical properties of solid 3He are described and the physical observable calculated using Monte Carlo path integral techniques is defined. The relationship between the path integral and the observable is outlined. The parallel algorithm is explained and finally, timing results are presented for runs of the identical code on one parallel computer and two sequential computers: the NCUBE hypercube, the Cray XMP, the Elxsi 6400.
Probing a scene of non convex polyhedra
Authors: J. D. Boissonnat, M. Yvinec
Venue: Proceedings of the fifth annual symposium on Computational geometry (1989)

We show, in this paper, how one can probe a class of non convex polyhedra and scenes of disjoint such polyhedra. A polyhedron of that class has convex faces; any two faces are not coplanar and any two edges are not colinear. The basic step of our method is a strategy for probing a single simple polygon with no colinear edges. When each probe outcome consists of a contact point and the normal to the object at the point, we present a strategy that discovers the exact shape of a simple polygon with no colinear edges by means of at most 3n - 3 probes, which is shown to be optimal in the worst-case. This strategy can be extended to probe a family of disjoint polygons. It can also be applied in the supporting planes of the faces of a scene of polyhedra of the class above. If the scene consists of k polyhedra with altogether n faces, we show that 8n2 - 6n + k probes are sufficient to discover the exact shapes of the polyhedra.
Demeter: a case study of software growth through parameterized classes
Authors: K. J. Lieberherr, A. J. Riel
Venue: Proceedings of the 10th international conference on Software engineering (1988)

Demeter&trade; is a system designed for the development of large software projects using a new software design methodology which focuses on growing rather than building software. We describe the software development process as one of growth and evolution as opposed to building and rebuilding because most complex objects in the real world are grown and not built. Since software design is obviously a complex process this new paradigm may be helpful in unraveling some of the problems associated with current software design practices. Demeter begins by providing an ideal environment for the sprouting and nurturing of a seed (data dictionary) into a plant (large scale software project). In addition, through the combined use of object-oriented programming technology, and parameterized classes, Demeter provides a facility for the reuse of software which was developed in previous software projects.
New lower bounds for parallel computation
Authors: Ming Li, Yaacov Yesha
Venue: Journal of the ACM (JACM) (1989)

Lower bounds are proven on the parallel-time complexity of several basic functions on the most powerful concurrent-read concurrent-write PRAM with unlimited shared memory and unlimited power of individual processors (denoted by PRIORITY(&infin;)): It is proved that with a number of processors polynomial in n, &OHgr; (log n) time is needed for addition, multiplication or bitwise OR of n numbers, when each number has n' bits. Hence even the bit complexity (i.e., the time complexity as a function of the total number of bits in the input) is logarithmic in this case. This improves a beautiful result of Meyer auf der Heide and Wigderson [22]. They proved a log n lower bound using Ramsey-type techniques. Using Ramsey theory, it is possible to get an upper bound on the number of bits in the inputs used. However, for the case of polynomially many processors, this upper bound is more than a polynomial in n. An &OHgr; (log n) lower bound is given for PRIORITY(&infin;) with no(1) processors on a function with inputs from {0, 1}, namely for the function &fnof;(x1, &hellip; , xn,) = &Sgr; nl- 1 xlai where a is fixed and xi &egr; {0, 1}. Finally, by a new efficient simulation of PRIORITY(&infin;) by unbounded fan-in circuits, that with less than exponential number of processors, it is proven a PRIORITY(&infin;) cannot compute PARITY in constant time, and with nO(1) processors &OHgr;(@@@@log n) time is needed. The simulation technique is of independent interest since it can serve as a general tool to translate circuit lower bounds into PRAM lower bounds. Further, the lower bounds in (1) and (2) remain valid for probabilistic or nondeterministic concurrent-read concurrent-write PRAMS.
Analysis of a simple yet efficient convex hull algorithm
Authors: M. Golin, R. Sedgewick
Venue: Proceedings of the fourth annual symposium on Computational geometry (1988)

This paper is concerned with a simple, rather intuitive preprocessing step that is likely to improve the average-case performance of any convex hull algorithm. For n points randomly distributed in the unit square, we show that a simple linear pass through the points can eliminate all but &Ogr;(&radic;n) of the points by showing that a simple superset of the remaining points has size c&radic;n + &ogr;(&radic;n). We give a full implementation of the method, which should be useful in any practical application for finding convex hulls. Most of the paper is concerned with an analysis of the number of points eliminated by the procedure, including derivation of an exact expression for c. Extensions to higher dimensions are also considered.
Exploiting inheritance and structure semantics for effective clustering and buffering in an object-oriented DBMS
Authors: E. E. Chang, R. H. Katz
Venue: ACM SIGMOD Record (1989)

Object-oriented databases provide new kinds of data semantics in terms of inheritance and structural relationships. This paper examines how to use these additional semantics to obtain more effective object buffering and clustering. We use the information collected from real-world object-oriented applications, the Berkeley CAD Group's OCT design tools, as the basis for a simulation model with which to investigate alternative buffering and clustering strategies. Observing from our measurements that real CAD applications exhibit high data read to write ratios, we propose a run-time clustering algorithm whose initial evaluation indicates that system response time can be improved by a factor of 200% when the read/write ratio is high. We have also found it useful to limit the amount of I/O allowed to the clustering algorithm as it examines candidate pages for clustering at run-time. Basically, there is little performance distinction between limiting reclustering to a few I/Os or many, so a low limit on I/O appears to be acceptable. We also examine, under a variety of workload assumptions, context-sensitive buffer replacement policies with alternative prefetching policies.
Interpreting statutory predicates
Authors: E. L. Rissland, D. B. Skalak
Venue: Proceedings of the 2nd international conference on Artificial intelligence and law (1989)

In this paper we discuss a hybrid approach to the problem of statutory interpretation that involves combining our past approach to case-based reasoning (&ldquo;CBA&rdquo;), as exemplified in our previous HYPO and TAX-HYPO systems, with traditional rule-based reasoning (&ldquo;RBR&rdquo;), as exemplified by expert systems. We do not tackle the fullblown version of statutory interpretation, which would include reasoning with legislative intent or other normative aspects (the &ldquo;ought&rdquo;), but confine ourselves to reasoning with explicit cases and rules. We discuss strategies that can be used to guide interpretation, particularly the interleaving of CBR and RBR, and how they are used in an agenda-based architecture, called CABARET, which we are currently developing in a general way and experimenting with in the particular area of Section &sect;280A(c)(1) of the U.S. Internal Revenue Code, which deals with the so called &ldquo;home office deduction&rdquo;.
CSCW'88: report on the conference review of the proceedings
Authors: J. Grudin
Venue: ACM SIGCHI Bulletin (1989)

This article is a combined trip report and review of the published proceedings of the CSCW '88 Conference on Computer-Supported Cooperative Work. The conference proceedings are available from ACM Order Department, PO Box 64145, Baltimore, MD 21264, $22 for members and $30 for non-members; credit card orders are taken at (800) 342-6626.
On the Accuracy and Stablility of Clocks Synchronized by the Network Time Protocol in the Internet System
Authors: David L. Mills
Venue: ACM SIGCOMM Computer Communication Review (1989)

This paper describes a series of experiments involving over 100,000 hosts of the Internet system and located in the U.S., Europe and the Pacific. The experiments are designed to evaluate the availability, accuracy and reliability of international standard time distribution using the Internet and the Network Time Protocol (NTP), which has been designated an Internet Standard protocol. NTP is designed specifically for use in a large, diverse internet system operating at speeds from mundane to lightwave. In NTP a distributed subnet of time servers operating in a self-organizing, hierarchical, master-slave configuration exchange precision timestamps in order to synchronize host clocks to each other and national time standards via wire or radio.The experiments are designed to locate Internet hosts and gateways that provide time by one of three time distribution protocols and evaluate the accuracy of their indications. For those hosts that support NTP, the experiments determine the distribution of errors and other statistics over paths spanning major portions of the globe. Finally, the experiments evaluate the accuracy and reliability of precision timekeeping using NTP and typical Internet paths involving ARPANET, NSFNET and regional networks. The experiments demonstrate that timekeeping throughout most portions of the Internet can be maintained to an accuracy of a few tens of milliseconds and a stability of a few milliseconds per day, even in cases of failure or disruption of clocks, time servers or networks.
Extending Objects to Support Multiple Interfaces and Access Control
Authors: Brent Hailpern, Harold Ossher
Venue: IEEE Transactions on Software Engineering (1990)

A mechanism, called views, that allows programmers to specify multiple interfaces for objects and to control explicitly access to each interface is described. This mechanism provides a simple and flexible means of specifying enforceable access restrictions at many levels of granularity. It also results in system organization that supports browsing based on a number of different criteria. Views is defined, some examples of its uses are given, the impact of views on system organization is discussed, and five approaches to implementing views are outlined.
Rational continuity: parametric, geometric, and Frenet frame continuity of rational curves
Authors: M. E. Hohmeyer, B. A. Barsky
Venue: ACM Transactions on Graphics (TOG) (1989)

The parametric, geometric, or Frenet frame continuity of a rational curve has often been ensured by requiring the homogeneous polynomial curve associated with the rational curve to possess either parametric, geometric, or Frenet frame continuity, respectively. In this paper, we show that this approach is overly restrictive and derive the constraints on the associated homogeneous curve that are both necessary and sufficient to ensure that the rational curve is either parametrically, geometrically, or Frenet frame continuous.