ppxscal/embedding_network huggingface dataset:
QPC2: A constructive calculus with parameterized specifications
Authors: Yukihide Takayama
Venue: Journal of Symbolic Computation (1993)

A second order constructive calculus is presented in this paper. The idea is not to give a yet another system but to restrict higher order calculi such as the Calculus of Constructions (CoC) [2, 3] and Martin-Lof's Intuitionistic Type Theory (ITT) with the hierarchy of universes [10]. One of the aims of the restriction is to provide a program synthesis system which directly generates functional programs with the program constructs such as if-then-else and pairing. Unlike CoC, F [5], and F"@w [4], we do not use Prawitz coding of logical connectives [15] because, if we use the coding, the constructs such as if-then-else and pairing are not primitives but the functionals defined in higher order lambda terms. Another aim of the restriction is to find a subset of existing higher order systems which is necessary and sufficient for parameterized specifications. The obtained system, which is called QPC"2, roughly corresponds to a subset of ITT with the universes U"1 and U"2, but has a few differences. First of all, unlike ITT QPC"2 allows universal quantification over predicates which enables a flexible description of parameterized specifications. Secondly. we take type-free approach along the line of PX [8] and SST [16] in which types and formulas are clearly separated and they are linked with realizability interpretation. Thus, each universe is separated into two parts: one for types and another for formulas. This distinction of types and formulas combined with the realizability technique enables the program extraction without redundancy. A program scheme is extracted from the proof of a given parameterized specification, and it is reduced to a program when first order formulas are substituted to parameters. Because of the suitable restriction of second order formulas, most part of the instantiation procedure can be easily performed automatically. Also, QPC"2 together with the various optimization techniques for first order constructive calculus such as the extended projection method [19] can synthesize natural programs.
Parametric databases: seamless integration of spatial, temporal, belief and ordinary data
Authors: Shashi K. Gadia
Venue: ACM SIGMOD Record (1993)

Our model, algebra and SQL-like query language for temporal databases extend naturally to parametric data, of which spatial, temporal, spatio-temporal, belief and ordinary data are special cases.
Temporal reasoning in Timegraph I&ndash;II
Authors: Alfonso Gerevini, Lenhart Schubert, Stephanie Schaeffer
Venue: ACM SIGART Bulletin (1993)

We describe two temporal reasoning systems called Timegraph I and II, which can efficiently manage large sets of relations in the Point Algebra as well as metric information. Our representation is based on timegraphs, graphs partitioned into a set of chains on which the search is supported by a metagraph data structure. Timegraph I was originally developed by Taugher, Schubert and Miller in the context of story comprehension. Timegraph II provides useful extensions which makes the system more expressive in the representation of qualitative information and suitable for a larger class of applications. Experimental results show that our approach is very efficient, especially when the given relations admit representation as a collection of chains connected by relatively few cross-chain links.
The beginning and development of FORMAC (FORmula MAnipulation Compiler)
Authors: Jean E. Sammet
Venue: The second ACM SIGPLAN conference on History of programming languages (1993)

The first widely available programming language for symbolic mathematical computation to have significant practical usage was FORMAC (FORmula MAnipulation Compiler). This paper discusses the earliest conceptual work in detail, and then provides information about later developments of the language. Other languages and systems of the early and mid-1960s are described briefly, with emphasis on their relation to FORMAC. There are also a few glimpses into the software management process at IBM. Finally there is an evaluation of FORMAC and its influence.
Reconfiguring Fault-Tolerant Two-Dimensional Array Architectures
Authors: Nathaniel J. Davis,  IV, F. Gail Gray, Joseph A. Wegner, Shannon E. Lawson, Vinay Murthy, Tennis S. White
Venue: IEEE Micro (1994)

Circuit complexities reduce overall reliability and mean-time-between-failure rates of today's very large processing arrays. Our integrated, three-level hierarchy of reconfiguration methods provides reasonable levels of fault tolerance for such systems. Operating in a completely distributed fashion, the hierarchy does not require that any components be fault free. It significantly improves array reliability by using a combination of transient fault rollback techniques and local and global reconfiguration algorithms.
Human interaction for symbolic computation: RIACA workshop, Amsterdam, March 10&ndash;11, 1994
Authors: André Heck
Venue: ACM SIGCHI Bulletin (1994)

The Research Institute for Applications of Computer Algebra (RIACA), in Amsterdam, The Netherlands, has as its goal the research of applications of computer algebra in the fields of mathematics and sciences, engineering, etc. It aims to be an institute with a strong international visibility.
Some geometric applications of Dilworth's theorem
Authors: János Pach, Jenő Tőrőcsik
Venue: Proceedings of the ninth annual symposium on Computational geometry (1993)

A geometric graph is a graph drawn in the plane such that its edges are closed line segments and no 3 vertices are collinear. We settle an old question of Avital, Hanani, Erdo huml:s, Kupitz and Perles by showing that every geometric graph with n vertices and m > k4n edges contains k+1 pairwise disjoint edges. We also prove that, given a set of points V and a set of axis-parallel rectangles in the plane, then either there are k+1 rectangles such that no point of V belongs to more than one of them, or we can find an at most 2&dot;105k8 element subset of V meeting all rectangles. This improves a result of Ding, Seymour and Winkler. Both proofs are based on Dilworth's theorem on partially ordered sets.
A metric time-point and duration-based temporal model
Authors: Federico A. Barber
Venue: ACM SIGART Bulletin (1993)

Constraint-based formalisms are a useful and common way to deal with temporal reasoning tasks. Assertions represent temporal constraints between temporal objects, time-points or intervals: Metric temporal constraints between time points permit us to express a minimum and maximum temporal distance between two time points and to define a valid temporal interval for each one. However, existing approaches have limited expressiveness for representing non-disjunctive qualitative constraints of point algebra and the empirical results do not seem very adequate for managing a great number of time points or when the time for management is limited.In this paper, an efficient and expressive time point and duration-based temporal representation model with metric constraints is presented. The main features of the model refer to the formal properties of the internal time model and the specific representation of temporal constraints, which integrates constraints on time-points and on durations and is more adequate for their computational management. Sound and complete management processes are specified on the basis of model properties. From this specification, two choices for management are proposed: (i) with neither propagation nor preprocessing techniques, complete management algorithms have an O(e*n) complexity, but a linear empirical cost is obtained; (ii) with complete propagation an O(n2) complexity is achieved.
On the sojourn time distribution in a finite capacity processor shared queue
Authors: Charles Knessl
Venue: Journal of the ACM (JACM) (1993)

We consider a processor shared M/M/1 queue that can accommodate at most a finite number K of customers. Using singular perturbation techniques, we construct asymptotic approximations to the distribution of a customer's sojourn time. We assume that K is large and treat several different cases of the model parameters and also treat different time scales. Extensive numerical comparisons are used to back up our asymptotic formulas. &mdash;Author's Abstract
Inertia&mdash;the reluctance of code motion?
Authors: William S. Shu
Venue: ACM SIGSOFT Software Engineering Notes (1993)

The effects of optimisation on debugging were characterised, first as metric-based distances along paths, and then within an algebraic framework [6, 7, 8]. In them, we observed algorithmic ambiguities which may seriously compromise the efficiency-though not the semantic definition-of a debugger for optimised programs. Informal observations appear to indicate enhanced performance if displaced codes were favoured for further displacements, and unmoved codes were preferentially left alone. This reluctance to change the "state of code motion" seems much like the physical quantity known as inertia. This paper highlights points to support the "inertial argument", and raises questions to be explored in relation to it.
Static analysis of upper and lower bounds on dependences and parallelism
Authors: William Pugh, David Wonnacott
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1994)

Existing compilers often fail to parallelize sequential code, even when a program can be manually transformed into parallel form by a sequence of well-understood transformations (as in the case for many of the Perfect Club Benchmark programs). These failures can occur for several reasons: the code transformations implemented in the compiler may not be sufficient to produce parallel code, the compiler may not find the proper sequence of transformations, or the compiler may not be able to prove that one of the necessary transformations is legal. When a compiler fails to extract sufficient parallelism from a program, the programmer may try to extract additional parallelism. Unfortunately, the programmer is typically left to search for parallelism without significant assistance. The compiler generally does not give feedback about which parts of the program might contain additional parallelism, or about the types of transformations that might be needed to realize this parallelism. Standard program transformations and dependence abstractions cannot be used to provide this feedback. In this paper, we propose a two-step approach to the search for parallelism in sequential programs. In the first step, we construct several sets of constraints that describe, for each statement, which iterations of that statement can be executed concurrently. By constructing constraints that correspond to different assumptions about which dependences might be eliminated through additional analysis, transformations, and user assertions, we can determine whether we can expose parallelism by eliminating dependences. In the second step of our search for parallelism, we examine these constraint sets to identify the kinds of transformations needed to exploit scalable parallelism. Our tests will identify conditional parallelism and parallelism that can be exposed by combinations of transformations that reorder the iteration space (such as loop interchange and loop peeling). This approach lets us distinguish inherently sequential code from code that contains unexploited parallelism. It also produces information about the kinds of transformations needed to parallelize the code, without worrying about the order of application of the transformations. Furthermore, when our dependence test is inexact we can identify which unresolved dependences inhibit parallelism by comparing the effects of assuming dependence or independence. We are currently exploring the use of this information in programmer-assisted parallelization.
Fourteen Ways to Say Nothing With Scientific Visualization
Authors: Al Globus, Eric Raible
Venue: Computer (1994)

In "Twelve Ways to Fool the Masses When Giving Performance Results on Parallel Computers," (see Supercomputer Rev., vol.4, no.8, p.54-5, 1991) David Bailey ends with the admonition, "Conclude your technical presentation and roll the videotape. Audiences love razzle-dazzle color graphics, and this material often helps deflect attention from the substantive technical issues." Unfortunately, Bailey gives no guidance in the means and methods for producing such a result. This article seeks to fill this void. There are numerous time-tested scientific visualization techniques for producing pretty pictures while avoiding unnecessary illumination of the data. Our collection has been culled from the scientific visualization literature and numerous presentations we have given and attended.
Modeling RPC performance
Authors: J. A. Rolia, M. Starkey, G. Boersma
Venue: Proceedings of the 1994 ACM SIGMETRICS conference on Measurement and modeling of computer systems (1994)

Distributed computing applications are collections of processes allocated across a network that cooperate to accomplish common goals. The applications require the support of a distributed computing runtime environment that provides services to help manage process concurrency and interprocess communication. This support helps to hide much of the inherent complexity of distributed environments via industry standard interfaces and permits developers to create more portable applications. The resource requirements of the runtime services can be significant and may impact application performance and system throughput. This paper describes work done to study the potential benefits of redesigning some aspects of the DCE RPC and its current implementation on a specific platform.
A hypertext query language for images
Authors: Li Yang
Venue: ACM SIGMOD Record (1994)

HYPERQUERY is a hypertext query language for object-oriented pictorial database systems. First, we discuss object calculus based on term rewriting. Then, example queries are used to illustrate language facilities. This query language has been designed with a flavor similar to QBE as the highly nonprocedural and conversational language for object-oriented pictorial database management system OISDBS.
Trigrams as index element in full text retrieval: observations and experimental results
Authors: Elizabeth S. Adams, Arnold C. Meltzer
Venue: Proceedings of the 1993 ACM conference on Computer science (1993)

A trigram is a three element sequence of characters. In this paper we demonstrate the effectiveness of a trigram based index for morphologically based retrievals from a full text document retrieval system. Retrieved documents are considered relevant if they contain exact matches for each of the query terms. Using this definition of relevance we consistently achieve a recall rate of 100%. In the experiments described here, we used sets of 100 anded three term queries, and the average precision per set varied from 47% to 87%. We propose a method for increasing the average precision to 100%. Using overlapping trigrams extracted from the Brown Corpus [KUCE67] and a character set of 45 elements, we found a horizontal asymptote near 11,000 for the number of entries in a trigram based index. Finally we show that a trigram based system provides a reasonable alternative to a word based one and is superior to it in retrievals of word fragments.
Finding an educational perspective for object-oriented development
Authors: Linda M. Northrop
Venue: ACM SIGPLAN OOPS Messenger (1993)

The object-oriented model has become exceedingly attractive as the best answer to the increasingly complex needs of the software development community. The initial boasts regarding quality, reuse, concurrency, and scalability are now being substantiated by documented software development experience. It is certainly appropriate, then, for educators who teach computer science (the current preparation for emerging software developers) to examine where object-oriented development best fits into the computer science curriculum. How much of the paradigm&mdash;language, analysis, design, management&mdash;ought to be addressed? At what level in an undergradute program are object-oriented techniques appropriate? What are the risks involved? How is the object-oriented approach effectively taught?
An Ada 9X subset for inheritance-based reuse and its translation to Ada 83 (Part 2)
Authors: Michael Hirasuna
Venue: ACM SIGAda Ada Letters (1994)

An object oriented reuse strategy based on the Ada 9X inheritance syntax is presented. This paper defines a minimal Ada 9X subset that implements inheritancebased reuse, and outlines its translation to Ada 83. Inheritance allows software modules to be reused without modification to the original source. It is preferred to the "copy and tailor" approach, which has limited software life-cycle benefit since tailored copies need to be tested and maintained.Reuse may be applied at the low level, for components, or at higher levels, for subsystems. Inheritance may be used at any level of reuse, but it is more important for the higher levels. Ada 83 does not support inheritance, but low-level reuse can still be implemented in the form of generic components [BOO87]. The cost advantage from low-level reuse is already assumed when planning today's software systems. Further cost savings must come from high-level reuse, which needs inheritance to be implemented properly. Inheritance will be fully supported in Ada 9X.The approach presented here may be used in a reuse plan for a system that will start development before Ada 9X becomes viable. The Ada 9X subset allows the system software to be structured for reuse, to be implemented in Ada 83, and to be ready for migration to Ada 9X.This is the second part of a two-part paper. The first part discussed the reuse strategy and defined an Ada 9X subset that will implement it. In this part, a translation from the Ada 9X subset to Ada 83 will be outlined.
Compiling Functional Parallelism on Distributed-Memory Systems
Authors: Santosh S. Pande, Dharma P. Agrawal, Jon Mauney
Venue: IEEE Parallel Distributed Technology: Systems Technology (1994)

We have developed an automatic compilation method that combines data- and code-based approaches to schedule a program's functional parallelism onto distributed memory systems. Our method works with Sisal, a parallel functional language, and replaces the back end of the Optimizing Sisal Compiler so that it produces code for distributed memory systems. Our extensions allow the compiler to generate code for Intel's distributed-memory Touchstone iPSC/860 machines (Gamma, Delta, and Paragon). The modified compiler can generate a partition that minimizes program completion time (for systems with many processors) or the required number of processors (for systems with few processors). To accomplish this, we have developed a heuristic algorithm that uses the new concept of threshold to treat the problem of scheduling as a trade-off between schedule length and the number of required processors. Most compilers for distributed memory systems force the programmer to partition the data or the program code. This modified version of a Sisal compiler handles both tasks automatically in a unified framework, and lets the programmer compile for a chosen number of processors.
How to Measure, Present, and Compare Parallel Performance
Authors: Lawrence A. Crowl
Venue: IEEE Parallel Distributed Technology: Systems Technology (1994)

Presentations of parallel performance can be easily and unintentionally distorted. Following some simple guidelines for measuring, presenting and comparing performance can greatly improve your presentation's accuracy and effectiveness.
Rethinking theoretical frameworks for HCI: report on an INTERCHI '93 workshop, Amsterdam, 24&ndash;25th April, 1993
Authors: Yvonne Rogers, Liam Bannon, Graham Button
Venue: ACM SIGCHI Bulletin (1994)

This one-and-a-half day workshop was intended to bring together researchers concerned about the state of theory in HCI, to discuss the adequacy of current theoretical frameworks and to examine more closely a number of alternative or extended frameworks that have been proposed for HCI. A further aim was to examine the recent 'turn to the social' and its implications for design practice in HCI. A wide variety of position papers (to put it mildly) were received, from which 15 were selected for presentation and discussion at the workshop. These ranged from critiques of the role of theory in HCI, expositions of various theoretical frameworks and the importance of considering methodology in relation to theory. Several authors also described how their alternative frameworks had enabled them to 'open their eyes' to alternative design solutions when analysing particular problems in a work context. The workshop was organized around three inter-related themes with the intention of engaging in both reflective and projected thinking. These were: i) What is the problem in HCI? (ii) What does my theoretical approach have to offer HCI, and (iii) How does my theory relate to practice? The participants were asked to address these questions in relation to their position papers. A general concern that became central to all themes was what theory was being used for in HCI. Several attempts at identifying and demystifying its role were suggested and it became clear that in fact it was being used in a multitude of ways. These included a background from which to: frame the problem, pose questions, to analyse, to describe and to explain. There was a general consensus, however, that the most 'scientific' use of a theory to propose and evaluate predictions about human performance was not appropriate for the current wave of alternative theory building. The lessons learnt from attempts to apply information-processing models to user performance were taken as sufficient evidence that the field of HCI is far too rich and complex to force into a set of hypotheses that can be quantitatively tested. Furthermore, the field is too diverse and changing to be formulated as a coherent theory of HCI. Alternatively, the role of theory in HCI should be to inform and guide system analysis and design.
Towards an analysis of range query performance in spatial data structures
Authors: Bernd-Uwe Pagel, Hans-Werner Six, Heinrich Toben, Peter Widmayer
Venue: Proceedings of the twelfth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems (1993)

In this paper, we motivate four different user defined window query classes and derive a probabilistic model for each of them. For each model, we characterize the efficiency of spatial data structures in terms of the expected number of data bucket accesses needed to perform a window query. Our analytical approach exhibits the performance phenomena independent of data structure and implementation details and whether the objects are points or non-point objects.
Optimally sparse spanners in 3-dimensional Euclidean space
Authors: Gautam Das, Paul Heffernan, Giri Narasimhan
Venue: Proceedings of the ninth annual symposium on Computational geometry (1993)

Let V be a set of n points in 3-dimensional Euclidean space. A subgraph of the complete Euclidean graph is a t-spanner if for any u and v in V, the length of the shortest path from u to v in the spanner is at most ttimes d(u, v). We show that for any t > 1, a greedy algorithm produces a t-spanner with O(n) edges, and total edge weight O(1).wt(MST), where MST is a minimum spanning tree of V.
An incremental algorithm for Betti numbers of simplicial complexes
Authors: Cecil Jose A. Delfinado, Herbert Edelsbrunner
Venue: Proceedings of the ninth annual symposium on Computational geometry (1993)

A general and direct method for computing the betti numbers of the homology groups of a finite simplicial complex is given. For subcomplexes of a triangulation of S3 this method has implementations that run in time O(n&dgr;(n)) and O(n), where n is the number of simplices in the triangulation. If applied to the family of &dgr;-shapes of a finite point set in R3 it takes time O(n&dgr;(n)) to compute the betti numbers of all &dgr;-shapes.