ppxscal/embedding_network huggingface dataset:
PORTS: a parallel, optimistic, real-time simulator
Authors: Kaushik Ghosh, Richard M. Fujimoto, Karsten Schwan
Venue: Proceedings of the eighth workshop on Parallel and distributed simulation (1994)

This paper describes issues concerning the design of an optimistic parallel discrete event simulation system that executes in environments that impose real-time constraints on the simulator's execution. Two key problems must be addressed by such a system. First the timing characteristics of the parallel simulator must be sufficiently predictable to allow one to guarantee that real-time deadlines for completing simulation computations will be met. Second, the optimistic computation must be able to interact with its surrounding environment with as little latency as possible, necessitating rapid commitment of I/O operations. To address the first question, we show that optimistic simulators that never send incorrect messages (sometimes called &ldquo;aggressive-no-risk&rdquo; simulators) provide sufficient predictability to allow traditional schedulability analysis techniques commonly used in real-time systems to be applied. We show that incremental state saving techniques introduce sufficient unpredictability that they are not well-suited for real-time environments. We observe that the traditional &ldquo;lowest timestamp first&rdquo; scheduling policy used in many optimistic parallel simulation systems is an optimal (in the real-time sense) scheduling algorithm when event timestamps and real-time deadlines are the same. Finally, to address the question for rapid commitment of I/O operations, we utilize a continuous GVT computation scheme for shared-memory multiprocessors where a new value of GVT is computed after processing each event in the simulation. These ideas are incorporated in a parallel, optimistic, real-time simulation system called PORTS. Initial performance measurements of the shared-memory based PORTS system executing on a Kendall Square Research multiprocessor are presented. Initial performance results are encouraging, demonstrating that PORTS achieves performance approaching that of a conventional Time Warp system for the benchmark programs that were tested.
On the semantics of theory change: arbitration between old and new information
Authors: Peter Z. Revesz
Venue: Proceedings of the twelfth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems (1993)

Katsuno and Mendelzon divide theory change, the problem of adding new information to a logical theory, into two types: revision and update. We propose a third type of theory change: arbitration. The key idea is the following: the new information is considered neither better nor worse than the old information represented by the logical theory. The new information is simply one voice against a set of others already incorporated into the logical theory. From this follows that arbitration should be commutative. First we define arbitration by a set of postulates and then describe a model-theoretic characterization of arbitration for the case of propositional logical theories. We also study weighted arbitration where different models of a theory can have different weights.
The Boyer benchmark meets linear logic
Authors: Henry G. Baker
Venue: ACM SIGPLAN Lisp Pointers (1993)

Of the Gabriel Lisp Benchmarks, the Boyer Benchmark ("Boyer") is the most representative of real AI applications, because it performs Prolog-like rule-directed rewriting, and because it relies heavily on garbage collection (GC) for the recovery of storage. We investigated the notion that such programs are unsuitable for explicit storage management---e.g., by means of a "linear" programming style in which every bound name dynamically occurs exactly once. We programmed Boyer in a "linear" fragment of Lisp in both interpretive-rule and compiled-rule versions, using both true linear (unshared) and reference count methods.We found that since the intermediate result of rewrite is unshared, the linear interpreted version is slower than the non-linear interpreted version, while the linear compiled version is slightly faster than the non-linear compiled version. When sharing is allowed, requiring reference counts for the linear versions, the linear shared versions are not competitive with the non-linear versions, except when "anchored pointers" are used. The anchored pointer reference count version, which reclaims storage, is still 1.25X slower than the non-linear version, which reclaims no storage.
Experts and expertise: the social context of expertise
Authors: P. L. Powell, J. H. Klein, N. A. D. Connell
Venue: Proceedings of the 1993 conference on Computer personnel research (1993)

Decision support and expert system construction attempts to make organisational expertise more widely available. Yet the prevailing paradigm of expertise is essentially that it is a uni-dimensional organisational resource, much as any other. This paper takes a holistic approach, examining the ways in which human experts and their expertise are systematically integrated into organisations. The socio-political nature of expertise is considered and the implications for ES and DSS examined.
Timely access to future funding announcements
Authors: Marianne Winslett, Iris Sheauyin Chu
Venue: ACM SIGMOD Record (1993)

The last issue of this column appeared six months ago, so in the interim many requests for proposals have been issued, with many of their due dates already past. We are happy to announce the availability of up-to-the-minute funding information on line, so that the Record's publication schedule need not prevent readers' timely access to funding information. In addition, we briefly recap recent requests for proposals from NASA, NLM, the Human Brain Project, the US Army, the US Navy, ARPA, NSF, and Intel; more detailed information on any of these (except Intel) can be found in the on-line archives. We also report on news at NSF and NIST.
The Miro DBMS
Authors: Michael Stonebraker
Venue: Proceedings of the 1993 ACM SIGMOD international conference on Management of data (1993)

This short paper explains the key object-relational (OR) DBMS technology used by the Miro DBMS.
Teaching practical object-oriented software engineering
Authors: Mahesh H. Dodani
Venue: Addendum to the proceedings on Object-oriented programming systems, languages, and applications (Addendum) (1992)

This paper describes the effort undertaken at the University of Iowa to institute a software engineering curriculum at the graduate level. We describe our experiences over 2 years in developing a pilot 2-semester course in object-oriented software engineering. This pilot course had the goals of introducing practical and realistic object-oriented software engineering to students, and developed several innovative techniques to achieve this goal on a very limited budget.
Relational parametricity and local variables
Authors: P. W. O'Hearn, R. D. Tennent
Venue: Proceedings of the 20th ACM SIGPLAN-SIGACT symposium on Principles of programming languages (1993)

J. C. Reynolds suggested that Strachey's intuitive concept of &ldquo;parametric&rdquo; (i.e., uniform) polymorphism is closely linked to representation independence, and used logical relations to formalize this principle in languages with type variables and user-defined types. Here, we use relational parametricity to address long-standing problems with the semantics of local-variable declarations, by showing that interactions between local and non-local entities satisfy certain relational criteria. The new model is based on a cartesian closed category of &ldquo;relation-preserving&rdquo; functors and natural transformations which is induced by a suitable category of &ldquo;possible worlds&rdquo; with relations assigned to its objects and morphisms. The semantic interpretation supports straightforward validations of all the test equivalences that have been proposed in the literature, and encompasses standard methods of reasoning about data representations; however, it is not known whether it is fully abstract.
Graph types
Authors: Nils Klarlund, Michael I. Schwartzbach
Venue: Proceedings of the 20th ACM SIGPLAN-SIGACT symposium on Principles of programming languages (1993)

Recursive data structures are abstractions of simple records and pointers. They impose a shape invariant, which is verified at compile-time and exploited to automatically generate code for building, copying, comparing, and traversing values without loss of efficiency. However, such values are always tree shaped, which is a major obstacle to practical use. We propose a notion of graph types, which allow common shapes, such as doubly-linked lists or threaded trees, to be expressed concisely and efficiently. We define regular languages of routing expressions to specify relative addresses of extra pointers in a canonical spanning tree. An efficient algorithm for computing such addresses is developed. We employ a second-order monadic logic to decide well-formedness of graph type specifications. This logic can also be used for automated reasoning about pointer structures.
Understanding ANOVA the APL way
Authors: Norman Thomson
Venue: ACM SIGAPL APL Quote Quad (1993)

Statistics text books expound the collection of techniques known as analysis of variance by using mathematical formulae. The term analysis of variance is something of a misnomer, since any analysis follows a primary exercise of partitioning sums of squares, which is entirely a matter of computation and data reorganization of the sort which APL is particularly adept at. The crux of the analysis stage then consists of making choices between what is often a bewilderingly large range of subtly different sums of squares partitions. The primitive function enclose with axis maps naturally into the data manipulations involved in sums of squares partitions for arrays. To the casual reader the latter are obscured rather clarified by the use of mathematical formulae alone. This paper explores the relationships between APL functions and ANOVA, and goes on to illustrate how these can be used in the context of a designed experiment.
A practical technique for bounding the time between events in concurrent real-time systems
Authors: J. Corbett, G. Avrunin
Venue: Proceedings of the 1993 ACM SIGSOFT international symposium on Software testing and analysis (1993)

Showing that concurrent systems satisfy timing constraints on their behavior is difficult, but may be essential for critical applications. Most methods are based on some form of reachability analysis and require construction of a state space of size that is, in general, exponential in the number of components in the concurrent system. In an earlier paper with L. K. Dillon and J. E. Wileden, we described a technique for finding bounds on the time between events without enumerating the state space, but the technique applies chiefly to the case of logically concurrent systems executing on a uniprocessor, in which events do not overlap in time. In this paper, we extend that technique to obtain upper bounds on the time between events in maximally parallel concurrent systems. Our method does not require construction of the state space and the results of preliminary experiments show that, for at least some systems with large state spaces, it is quite tractable. We also briefly describe the application of our method to the case in which there are multiple processors, but several processes run on each processor.
A non-blocking transaction data flow graph based approach for replicated data
Authors: P. Krishna Reddy, S. Bhalla
Venue: ACM SIGOPS Operating Systems Review (1993)

Regplicated data management systems adopt the 1-copy serializability criteria for processing transactions. In order to achieve this goal, many approaches, rely on obtaining votes from other sites, for processing update requests. In this paper, a technique for generation of precedence graphs for each transaction execution is proposed. The transaction data flow graph approach is a fully distributed approach. The proposed technique, is free from deadlocks, and avoids resubmission of transactions.
An exploration of group member satisfaction
Authors: Murali Venkatesh, Jacques C. Verville
Venue: Proceedings of the 1993 conference on Computer personnel research (1993)

This paper reports results from an empirical, field-based exploration of the components of group member satisfaction. Items included in the instrument were identified via literature review. Additionally, a group brainstorming session with supervisory and middle management level employees of a large high technology firm was used to supplement items identified from the literature. The resulting instrument, with a focus on both within-meeting as well as pre- and post-meeting aspects of group work, was administered to a convenience sample of 166 respondents from the high technology firm. Results of factor and reliability analyses are reported. This project is part of a program of research examining group member satisfaction from the psychological perspective of closure.
Efficient context-sensitive plausible inference for information disclosure
Authors: P. D. Bruza, L. C. van der Gaag
Venue: Proceedings of the 16th annual international ACM SIGIR conference on Research and development in information retrieval (1993)

Plausible inference is an essential aspect of logic-based information disclosure. This paper proposes a context-sensitive plausible inference mechanism based on a so-called index expression belief network. Plausible inference is cloaked as probabilistic evidence propagation within this network. Preliminary experiments show general evidence propagation algorithms to be too inefficient for real-life information disclosure applications. The paper sketches two optimizations whereby efficient, special-purpose evidence propagation may be realized.
Is speech recognition usable?: an exploration of the usability of a speech-based voice mail interface
Authors: Marita Franzke, Adam N. Marx, Teresa L. Roberts, George E. Engelbeck
Venue: ACM SIGCHI Bulletin (1993)

US WEST Advanced Technologies conducted an experiment using the "Wizard-of-Oz" paradigm. We compared a simulated speech recognition interface ("wizard") for a basic voice mail application to functionally similar touch-tone and operator assisted versions. This poster abstract highlights the results of this experiment, focussing on performance times and errors, the perceived ease of use, and a description of the linguistic characteristics of users' utterances. The results are interpreted to be in favor of applying speech recognition technology to user interfaces.
Nonuniform learnability
Authors: Gyora M. Benedek, Alon Itai
Venue: Journal of Computer and System Sciences (1994)

The learning model of Valiant is extended to allow the number of examples required for learning to depend on the particular concept to be learned, instead of requiring a uniform bound for all concepts of a concept class. This extension, called nonuniform learning, enables learning many concept classes not learnable by the previous definitions. Nonuniformly learnable concept classes are characterized. Some examples (Boolean formulae, recursive, and r.e. sets) are shown to be nonuniformly learnable by a polynomial (in the size of the representation of the concept and in the error parameters) number of examples, but not necessarily in polynomial time. Restricting the learning protocol such that the learner has to commit himself after a finite number of examples does not affect the concept classes which can be learned. An extension of nonuniform learnability to nonuniform learnability with respect to specific distributions is presented.
Formal aspects of concurrency control in long-duration transaction systems using the NT/PV model
Authors: Henry F. Korth, Greg Speegle
Venue: ACM Transactions on Database Systems (TODS) (1994)

In the typical database system, an execution is correct if it is equivalent to some serial execution. This criterion, called serializability, is unacceptable for new database applications which require long-duration transactions. We present a new transaction model which allows correctness criteria more suitable for these applications. This model combines three enhancements to the standard model: nested transactions, explicit predicates, and multiple versions. These features yield the name of the new model, nested transactions with predicates and versions, or NT/PV.The modular nature of the NT/PV model allows a straightforward representation of simple systems. It also provides a formal framework for describing complex interactions. The most complex interactions the model allows can be captured by a protocol which exploits all of the semantics available to the NT/PV model. An example of these interactions is shown in a CASE application. The example shows how a system based on the NT/PV model is superior to both standard database techniques and unrestricted systems in both correctness and performance.
Simulation with DEVS-CLOS (abstract)
Authors: Suleyman Sevinc
Venue: ACM SIGPLAN OOPS Messenger (1993)

Simulation with DEVS-CLOS Suleyman Sevinc, University of Sydney , Australia This tutorial has two purposes: to show how the features of CLOS affect a design and to describe the design of a general-purpose simulation system. The tutorial is designed for those who want to understand the practical importance of the unique features of CLOS and also those who would like to learn how to use or build object-oriented simulation systems. The tutorial emphasizes the underlying model of object-oriented programming in CLOS and distinguishes it from other models. It also describes the requirements of a simulation system and the design of DEVS-CLOS, a publicly available simulation system. DEVS-CLOS is an extension to CLOS that supports modeling and simulation. It supports visualization, supports hierarchical design of simulations, allows first-order logic in models, and supports adaptive system simulation. The tutorial shows how a system like DEVS-CLOS can be used to solve typical simulation problems, and how CLOS concepts like multimethods, multiple inheritance, pre- and post-methods and dispatching algorithms were used in the design of DEVS-CLOS.
A Parallel Algorithm for Computing the Singular Value Decomposition of a Matrix
Authors: E. R. Jessup, D. C. Sorensen
Venue: SIAM Journal on Matrix Analysis and Applications (1994)

A parallel algorithm for computing the singular value decomposition of a matrix is presented. The algorithm uses a divide and conquer procedure based on a rank one modification of a bidiagonal matrix. Numerical difficulties associated with forming the product of a matrix with its transpose are avoided, and numerically stable formulae for obtaining the left singular vectors after computing updated right singular vectors are derived. A deflation technique is described that, together with a robust root finding method, assures computation of the singular values to full accuracy in the residual and also assures orthogonality of the singular vectors.
Explicit polymorphism and CPS conversion
Authors: Robert Harper, Mark Lillibridge
Venue: Proceedings of the 20th ACM SIGPLAN-SIGACT symposium on Principles of programming languages (1993)

We study the typing properties of CPS conversion for an extension of F&ohgr; with control operators. Two classes of evaluation strategies are considered, each with call-by-name and call-by-value variants. Under the &ldquo;standard&rdquo; strategies, constructor abstractions are values, and constructor applications can lead to non-trivial control effects. In contrast, the &ldquo;ML-like&rdquo; strategies evaluate beneath constructor abstractions, reflecting the usual interpretation of programs in languages based on implicit polymorphism. Three continuation passing style sub-languages are considered, one on which the standard strategies coincide, one on which the ML-like strategies coincide, and one on which all strategies coincide. Compositional, type-preserving CPS transformation algorithms are given for the standard strategies, resulting in terms on which all evaluation strategies coincide. This has as a corollary the soundness and termination of well-typed programs under the standard evaluation strategies. A similar result is obtained for the ML-like call-by-name strategy. In contrast, such results are obtained for the call-by-name strategy. In contrast, such results are obtained for the call-by value ML-like strategy only for a restricted sub-language in which constructor abstractions are limited to values.
Analog input device physical characteristics
Authors: James S. Lipscomb, Michael E. Pique
Venue: ACM SIGCHI Bulletin (1993)

When selecting a device, a designer should compare alternative devices point-by-point. When making a tentative decision, one needs to know what other possibilities have been locked out. A classification graph does this.New here is this classification graph. Also new are several terms: free, sticky, unbounded, bounded, homogeneous and volatile.We developed this classification of existing devices while building the GRIP-75 interactive molecular computer graphics system [2, 11] and refined the classification during discussions with other system builders where we used this classification to map out alternatives. This paper is founded on practice and experience, not on classification theory.
Exploiting task and data parallelism on a multicomputer
Authors: Jaspal Subhlok, James M. Stichnoth, David R. O'Hallaron, Thomas Gross
Venue: ACM SIGPLAN Notices (1993)

For many applications, achieving good performance on a private memory parallel computer requires exploiting data parallelism as well as task parallelism. Depending on the size of the input data set and the number of nodes (i.e., processors), different tradeoffs between task and data parallelism are appropriate for a parallel system. Most existing compilers focus on only one of data parallelism and task parallelism. Therefore, to achieve the desired results, the programmer must separately program the data and task parallelism. We have taken a unified approach to exploiting both kinds of parallelism in a single framework with an existing language. This approach eases the task of programming and exposes the tradeoffs between data and task parallelism to compiler. We have implemented a parallelizing Fortran compiler for the iWarp system based on this approach. We discuss the design of our compiler, and present performance results to validate our approach.
HALSIM&mdash;a very fast SPARC V9 behavioral model
Authors: David Barach, Jaspal Kohli, John Slice, Marc Spaulding, Rajeev Bharadhwaj, Don Hudson, Cliff Neighbors, Nirmal Saxena, Rolland Crunk
Venue: ACM SIGARCH Computer Architecture News (1994)

This paper describes several implementation techniques used in HAL's 250 KIPS SPARC V9 behavioral model. Beyond presenting the details of our processor model, we describe several areas of innovation: architectural state-vector capture for injection into a gate-level hardware model, using an EDC polynomial-based signature scheme to verify a hardware design; obtaining accurate kernel and user-mode instruction trace data.
Parallel multiplication: a case study in parallel programming
Authors: C. K. Yuen, M. D. Feng
Venue: ACM SIGPLAN Notices (1994)

Six versions of a parallel program for multiplication are presented, and compared in terms of their efficiencies. They illustrate the bottom up and top down methods of program structure design, and the use of tuplespace and speculative processing in parallel programming. The ideas are also applicable to general AND/OR parallel problems.