ppxscal/embedding_network huggingface dataset:
Accurate modeling of the hybrid hash join algorithm
Authors: Jignesh M. Patel, Michael J. Carey, Mary K. Vernon
Venue: Proceedings of the 1994 ACM SIGMETRICS conference on Measurement and modeling of computer systems (1994)

The join of two relations is an important operation in database systems. It occurs frequently in relational queries, and join performance is a significant factor in overall system performance. Cost models for join algorithms are used by query optimizers to choose efficient query execution strategies. This paper presents an efficient analytical model of an important join method, the hybrid hash join algorithm, that captures several key features of the algorithm's performance&mdash;including its intra-operator parallelism, interference between disk reads and writes, caching of disk pages, and placement of data on disk(s). Validation of the model against a detailed simulation of a database system shows that the response time estimates produced by the model are quite accurate.
Automatic isolation of compiler errors
Authors: David B. Whalley
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1994)

This paper describes a tool called vpoiso that was developed to isolate errors automatically in the vpo compiler system. The two general types of compiler errors isolated by this tool are optimization and nonoptimization errors. When isolating optimization errors, vpoiso relies on the vpo optimizer to identify sequences of changes, referred to as transformations, that result in semantically equivalent code and to provide the ability to stop performing improving (or unnecessary) transformations after a specified number have been performed. A compilation of a typical program by vpo often results in thousands of improving transformations being performed. The vpoiso tool can automatically isolate the first improving transformation that causes incorrect output of the execution of the compiled programs by using a binary search that varies the number of improving transformation performed. Not only is the illegal transformation automatically isolated, but vpoiso also identifies the location and instant the transformation is performed in vpo. Nonoptimization errors occur from problems in the front end, code generator, and necessary transformations in the optimizer. If another compiler is available that can produce correct (but perhaps more inefficient) code, then vpoiso can isolate nonoptimization errors to a single function. Automatic isolation of compiler errors facilitates retargeting a compiler to a new machine, maintenance of the compiler, and supporting experimentation with new optimizations.
Unifying and Optimizing Parallel Linear Algebra Algorithms
Authors: Michele Angelaccio, Michele Colajanni
Venue: IEEE Transactions on Parallel and Distributed Systems (1993)

Two issues in linear algebra algorithms for multicomputers are addressed. First, how tounify parallel implementations of the same algorithm in a decomposition-independent way. Second, how to optimize naive parallel programs maintaining the decompositionindependence. Several matrix decompositions are viewed as instances of a more generalallocation function called subcube matrix decomposition. By this meta-decomposition, aprogramming environment characterized by general primitives that allow one to designmeta-algorithms independently of a particular decomposition. The authors apply such aframework to the parallel solution of dense matrices. This demonstrates that most of theexisting algorithms can be derived by suitably setting the primitives used in themeta-algorithm. A further application of this programming style concerns the optimization of parallel algorithms. The idea to overlap communication and computation has been extended from 1-D decompositions to 2-D decompositions. Thus, a first attempt towards a decomposition-independent definition of such optimization strategies is provided.
An evaluation of query processing strategies using the TIPSTER collection
Authors: James P. Callan, W. Bruce Croft
Venue: Proceedings of the 16th annual international ACM SIGIR conference on Research and development in information retrieval (1993)

The TIPSTER collection is unusual because of both its size and detail. In particular, it describes a set of information needs, as opposed to traditional queries. These detailed representations of information need are an opportunity for research on different methods of formulating queries. This paper describes several methods of constructing queries for the INQUERY information retrieval system, and then evaluates those methods on the TIPSTER document collection. Both AdHoc and Routing query processing methods are evaluated.
Adapting a debugger for optimised programs
Authors: William S. Shu
Venue: ACM SIGPLAN Notices (1993)

An interactive source-level debugger for optimised programs is built where the features of either debugger or optimiser may be fully expressed without undue hindrance from each other, nor degradation when they are used separately. Tracker is the link between the tools that assures this. Its role is to correct for any distortions introduced by optimisation in the debugging process. It stems from a view that opfimisation and debugging perform the same actions on a program code, albeit for different purposes. This paper discusses implementation aspects in adapting a debugger and an optimiser in this model for debugging optimised programs.
Necessary Conditions for Optimal Control of Stochastic Systems with Random Jumps
Authors: Shanjian Tang, Xunjing Li
Venue: SIAM Journal on Control and Optimization (1994)

A maximum principle is proved for optimal controls of stochastic systems with random jumps. The control is allowed to enter into both diffusion and jump terms. The form of the maximum principle turns out to be quite different from the one corresponding to the pure diffusion system (the word "pure" here means the absence of the jump term). In calculating the first-order coefficient for the cost variation, only a property for Lebesgue integrals of scalar-valued functions in the real number space ${\Cal R}$ is used. This shows that there is no essential difference between deterministic and stochastic systems as far as the derivation of maximum principles is concerned.
HCI in the school of computer science at Carnegie Mellon University
Authors: Bonnie E. John, James H. Morris
Venue: Proceedings of the INTERACT '93 and CHI '93 conference on Human factors in computing systems (1993)

People use computers to accomplish tasks. Consequently, understanding human capabilities and tasks is as important to the design of computer systems as understanding computer technologies. The School of Computer Science (SCS) at Carnegie Mellon University (CMU) has become home to an interdisciplinary community that performs research on HCI issues, develops systems using HCI methods of design and evaluation, and trains students in the theory and skills necessary to become HCI professionals.
PSPACE is provable by two provers in one round
Authors: Jin-yi Cai, Anne Condon, Richard J. Lipton
Venue: Journal of Computer and System Sciences (1994)

We show that every language in PSPACE, or equivalently, every language accepted by an unbounded round interactive proof system, ha a 1-round, 2-prover interactive proof system with exponentially small error probability. To obtain this result, we prove the correctness of a simple but powerful method for parallelizing 2-prover interactive proof systems to reduce their error.
A generalized carrier-null method for conservative parallel simulation
Authors: Kenneth R. Wood, Stephen J. Turner
Venue: ACM SIGSIM Simulation Digest (1994)

The carrier-null message approach to conservative-distributed discrete-event simulation can significantly reduce the number of synchronization messages required to avoid deadlock. In this paper we show that the original approach does not apply to simulations with arbitrary communication graphs and we propose a modified carrier-null approach which does. We present and discuss some preliminary results obtained using our approach to simulate digital logic circuits.
The logical data model
Authors: Gabriel M. Kuper, Moshe Y. Vardi
Venue: ACM Transactions on Database Systems (TODS) (1993)

We propose an object-oriented data model that generalizes the relational, hierarchical, and network models. A database scheme in this model is a directed graph, whose leaves represent data and whose internal nodes represent connections among the data. Instances are constructed from objects, which have separate names and values. We define a logic for the model, and describe a nonprocedural query language that is based on the logic. We also describe an algebraic query language and show that it is equivalent to the logical language.
A cryptographic file system for UNIX
Authors: Matt Blaze
Venue: Proceedings of the 1st ACM conference on Computer and communications security (1993)

Although cryptographic techniques are playing an increasingly important role in modern computing system security, user-level tools for encrypting file data are cumbersome and suffer from a number of inherent vulnerabilities. The Cryptographic File System (CFS) pushes encryption services into the file system itself. CFS supports secure storage at the system level through a standard Unix file system interface to encrypted files. Users associate a cryptographic key with the directories they wish to protect. Files in these directories (as well as their pathname components) are transparently encrypted and decrypted with the specified key without further user intervention; cleartext is never stored on a disk or sent to a remote file server. CFS can use any available file system for its underlying storage without modification, including remote file servers such as NFS. System management functions, such as file backup, work in a normal manner and without knowledge of the key.This paper describes the design and implementation of CFS under Unix. Encryption techniques for file system-level encryption are described, and general issues of cryptographic system interfaces to support routine secure computing are discussed.
Toward an ethos of rationale: commentary on &ldquo;The Role of Balloon Help&rdquo; by David K. Farkas
Authors: John M. Carroll
Venue: ACM SIGDOC Asterisk Journal of Computer Documentation (1993)

Professor Farkas' article address itself to a single interface technique. As he makes clear, the Balloon Help technique fills a fairly narrow role, which is nonetheless an interesting and potentially important role. The plan of the article is to first briefly explain what the technique is, then analyze its rationale in terms of theories and facts about users and documentation. Next, the article focuses down on some characteristic situations of use, specializing the rationale and reflecting more specifically on potential problems and strengths of the technique in these usage contexts. Finally, it turns to contrasts and conflicts of the technique with related techniques, and possibilities for extending the technique.
Ethical norms for technical communication: Plato, Aristotle, and Clark's &ldquo;rhetorical perspective&rdquo;
Authors: Arthur E. Walzer
Venue: ACM SIGDOC Asterisk Journal of Computer Documentation (1994)

In his "Ethics in Technical Communication: A Rhetorical Perspective," Gregory Clark argues convincingly that academicians and practitioners proceed from diametrically opposed assumptions in discussing ethics in the context of technical communication. Furthermore, Clark offers his essay as an example of an approach that might, were it widely imitated, promote the disciplined, progressive discussion on this topic that to this point has failed to evolve. But while Clark's intentions are admirable and his basic approach sound, the conclusions he reaches -- that an ethics for technical communication must be founded on a principle of cooperation -- cannot be derived from the approach he models. Clark's argument that the rhetorical tradition sanctions an ethics based on the principle of cooperation rests on misreadings of both Plato and Aristotle; and the Challenger case, which he sees as illustrating the need for a cooperative approach to communication, in fact proves just the opposite. A more realistic ethics for technical communication would begin in the acknowledgement that rhetoric more often spurs contention than cooperation and then take up the task of investigating the conditions that promote creative, rather than destructive, debate.
Spin-Lock Synchronization on the Butterfly and KSR1
Authors: Xiaodong Zhang, Robert Castañeda, Elisa W. Chan
Venue: IEEE Parallel Distributed Technology: Systems Technology (1994)

The drawbacks of the simple spin-lock limit its effective use to small critical sections. Applications with large critical sections and a large number of processors require more efficient algorithms to minimize processor and network overheads. Variations on the spin-lock have been tested on the Sequent Symmetry, a bus-based shared-memory multiprocessor. Algorithms for scalable synchronization have also been tested on the BBN Butterfly I, a large-scale shared-memory multiprocessor with a multistage interconnection network(MIN). We have extended the investigation to the BBN GP1000 and TC2000, both MIN-based multiprocessors with network contention heavier than that on the Butterfly I. We have also implemented algorithms on Kendall Square Research's KSR1, a hierarchical-ring multiprocessor system, to study the effects of cache coherence. The execution behavior of spin-lock algorithms is significantly different between MIN-based and HR-based architectures. Our tests suggest that HR-based architectures handle network and memory contention more efficiently than MIN-based architectures. However, our results also suggest how spin-locks can be made cost-effective on both.
Text categorization for multiple users based on semantic features from a machine-readable dictionary
Authors: Elizabeth D. Liddy, Woojin Paik, Edmund S. Yu
Venue: ACM Transactions on Information Systems (TOIS) (1994)

The text categorization module described here provides a front-end filtering function for the larger DR-LINK text retrieval system [Liddy and Myaeing 1993]. The model evaluates a large incoming stream of documents to determine which documents are sufficiently similar to a profile at the broad subject level to warrant more refined representation and matching. To accomplish this task, each substantive word in a text is first categorized using a feature set based on the semantic Subject Field Codes (SFCs) assigned to individual word senses in a machine-readable dictionary. When tested on 50 user profiles and 550 megabytes of documents, results indicate that the feature set that is the basis of the text categorization module and the algorithm that establishes the boundary of categories of potentially relevant documents accomplish their tasks with a high level of performance. This means that the category of potentially relevant documents for most profiles would contain at least 80% of all documents later determined to be relevant to the profile. The number of documents in this set would be uniquely determined by the system's category-boundary predictor, and this set is likely to contain less than 5% of the incoming stream of documents.
Approaching classical algorithms in APL2
Authors: Hanspeter Bieri, Felix Grimm
Venue: ACM SIGAPL APL Quote Quad (1993)

Classical algorithms and data structures as made popular by D.E. Knuth's "The Art of Computer Programming" have been largely ignored so far by APL2-programmers. This scepsis was understandable to a certain degree in the era of APL, but has lost its justification with the rise of APL2 and similar APL-successors. First the essence of classical algorithms as well as the principal ways of data structuring and accessing are reexamined. Then it is shown how pseudocodes or implementations of classical algorithms can be transfered one-to-one into APL2 almost automatically and often with an acceptable resulting performance. But, in general, the better way consists in maintaining only the general design principle behind a classical algorithm and combining it with the elegant and efficient specific possibilities of APL2. Both approaches are explained and illustrated by means of a typical classical algorithm from picture processing.
Taxonomic syntax for first order inference
Authors: David McAllester, Robert Givan
Venue: Journal of the ACM (JACM) (1993)

A new polynomial time decidable fragment of first order logic is identified, and a general method for using polynomial time inference procedures in knowledge representation systems is presented. The results shown in this paper indicate that a nonstandard &ldquo;taxonomic&rdquo; syntax is essential in constructing natural and powerful polynomial time inference procedures. The central role of taxonomic syntax in the polynomial time inference procedures provides technical support for the often-expressed intuition that knowledge is better represented in terms of taxonomic relationships than classical first order formulas. To use the procedures in a knowledge representation system, a &ldquo;Socratic proof system&rdquo; is defined, which is complete for first order inference and which can be used as a semi-automated interface to a first order knowledge base.
A history of ALGOL 68
Authors: C. H. Lindsey
Venue: The second ACM SIGPLAN conference on History of programming languages (1993)

ALGOL 68 is a language with a lot of &ldquo;history&rdquo;. The reader will hear of discord, resignations, unreadable documents, a minority report, and all manner of politicking. But although ALGOL 68 was produced by a committee (and an unruly one at that), the language itself is no camel. Indeed, the rigorous application of the principle of &ldquo;orthogonality&rdquo; makes it one of the cleanest languages around, as I hope to show. Moreover, when the language came to be revised, the atmosphere was quite different enabling a much more robust and readable defining document to be produced in a spirit of true cooperation. There are some lessons here for future language design efforts, but I am not optimistic that they have been learned. &mdash;Author's Abstract
A study of 80x86/80x87 floating-point execution
Authors: Zoran Miljanic, David R. Kaeli
Venue: ACM SIGSMALL/PC Notes (1992)

The evolution of a processor architecture must include enhancements to both the fixed and floating-point units. To increase overall performance, architectural and implementation performance improvements to the floating-point unit must keep pace with the performance enhancements made to the fixed-point unit. In this paper we evaluate the performance enhancements provided by the evolution of the floating-point co-processor for the Intel 80x86 family. Using a suite of traces, we show how code compiled for predecessor co-processors will perform on current floating-point implementations.
Introduction to object-oriented design (abstract)
Authors: Lori Stipp, Grady Booch
Venue: ACM SIGPLAN OOPS Messenger (1993)

Introduction to Object-Oriented Design Lori Stipp Grady Booth, Rational This tutorial describes the Booth method for object-oriented design, including details of the notation and the design process. It describes the principles that are necessary for thinking and abstracting in terms of classes and objects. The tutorial includes a number of examples, including war stories from specific projects. It also covers extensions to the notation beyond that described in Object-Oriented Design with Applications. This tutorial is a condensed version of Booths popular tutorial given at past OOPSLAs. If you have attended that in the past then you should attend tutorial 18 instead of this one.
Chip-Firing Games on Directed Graphs
Authors: Anders Björner, László Lovász
Venue: Journal of Algebraic Combinatorics: An International Journal (1992)

We consider the following (solitary) game: each node of a directed graph contains a pile of chips. A move consists of selecting a node with at least as many chips as its outdegree, and sending one chip along each outgoing edge to its neighbors. We extend to directed graphs several results on the undirected version obtained earlier by the authors, P. Shor, and G. Tardos, and we discuss some new topics such as periodicity, reachability, and probabilistic aspects.Among the new results specifically concerning digraphs, we relate the length of the shortest period of an infinite game to the length of the longest terminating game, and also to the access time of random walks on the same graph. These questions involve a study of the Laplace operator for directed graphs. We show that for many graphs, in particular for undirected graphs, the problem whether a given position of the chips can be reached from the initial position is polynomial time solvable.Finally, we show how the basic properties of the &ldquo;probabilistic abacus&rdquo; can be derived from our results.
The concurrency workbench: a semantics-based tool for the verification of concurrent systems
Authors: Rance Cleaveland, Joachim Parrow, Bernhard Steffen
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1993)

The Concurrency Workbench is an automated tool for analyzing networks of finite-state processes expressed in Milner's Calculus of Communicating Systems. Its key feature is its breadth: a variety of different verification methods, including equivalence checking, preorder checking, and model checking, are supported for several different process semantics. One experience from our work is that a large number of interesting verification methods can be formulated as combinations of a small number of primitive algorithms. The Workbench has been applied to the verification of communications protocols and mutual exclusion algorithms and has proven a valuable aid in teaching and research.
The impact of codes of ethics on information systems personnel
Authors: Susan J. Harrington
Venue: Proceedings of the 1994 computer personnel research conference on Reinventing IS : managing information technology in changing organizations: managing information technology in changing organizations (1994)

This research looks at the impact of company codes of ethics, as well as codes of ethics written specifically for information systems (I.S.) employees. Moreover, since the intent of ethics codes is to clarify responsibility, the personality characteristics of denial of responsibility and its interaction with exposure to codes of ethics was examined. The impact of codes and the personality characteristic of denial of responsibility were measured based on I.S. judgments concerning illegal software copying, computer cracking (sometimes called hacking), spreading viruses, corporate sabotage using the computer, and computer fraud. Denial of responsibility was found to be related to a variety of computer abuses and did interact with company codes of ethics to influence attitudes toward viruses and computer fraud.
Moore-Penrose Inversion of Square Toeplitz Matrices
Authors: Georg Heinig, Frank Hellinger
Venue: SIAM Journal on Matrix Analysis and Applications (1994)

Fast algorithms for the computation of the Moore-Penrose inverse $A^+$ of a square Toeplitz matrix $A$ are constructed based on Bezoutian representations of $A^+$. Two approaches are presented. The first approach is a recursion of the nested submatrices, the second approach uses generalized inverses of $A$ that are Bezoutians and a global formula.
A kleene-like characterization of languages accepted by systolic tree automata
Authors: E. Fachini, A. Monti
Venue: Journal of Computer and System Sciences (1994)

We present a Kleen-like characterization of the class of languages accepted by systolic binary tree automata, L(SBTA). This characterization uses union, intersection, restricted concatenation, restricted concatenation closure, and finite substitution closure. The restrictions we impose on the operator of concatenation are purely in terms of the length of the words to be concatenated.