ppxscal/embedding_network huggingface dataset:
CATS: computer aided testing of software
Authors: Maurice Jordan
Venue: ACM SIGAPL APL Quote Quad (1991)

This paper describes the implementation of an automated test system for APL functions. It extends an implementation of assertive comments in APL to derive a notation for formal specification using pre and post conditions. These conditions are APL statements and so can be built into test functions. Data supplied to provide examples is captured and subjected to mutations to test behaviour under edge conditions. The techniques make extensive use of modern APL ideas such as defined operators, phrasal forms and function assignment.
Scheduling periodic and aperiodic tasks in hard real-time computing systems
Authors: Tein-Hsiang Lin, Wernhuar Tarng
Venue: ACM SIGMETRICS Performance Evaluation Review (1991)

Scheduling periodic and aperiodic tasks to meet their time constraints has been an important issue in the design of real-time computing systems. Usually, the task scheduling algorithms in such systems must satisfy the deadlines of periodic tasks and provide fast response times for aperiodic tasks. A simple and efficient approach to scheduling real-time tasks is the use of a periodic server in a static preemptive scheduling algorithm. Periodic tasks, including the server, are scheduled at priori to meet their deadlines according to the knowledge of their periods and computation times. The scheduling of aperiodic tasks is then managed by the periodic server during its service time. In this paper, a new scheduling algorithm is proposed. The new algorithm creates a periodic server which will have the highest priority but not necessarily the shortest period. The server is suspended to reduce the overhead if there are no aperiodic tasks waiting, and is activated immediately upon the arrival of the next aperiodic task. After activated, the server performs its duty periodically until all waiting aperiodic tasks are completed. For a set of tasks scheduled by this algorithm, the deadlines of periodic tasks are guaranteed by a deterministic feasibility check, and the mean response time of aperiodic tasks are estimated using a queueing model. Based on the analytical results, we can determine the period and service time of the server producing the minimum mean response time for aperiodic tasks. The analytical results are compared with simulation results to demonstrate the correctness of our model.
Knowledge-Directed Interpretation of Mechanical Engineering Drawings
Authors: S. H. Joseph, T. P. Pridmore
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1992)

A methodology for the interpretation of images of engineering drawings is presented. The approach is based on the combination of schemata describing prototypical drawing constructs with a library of low-level image analysis routines and a set of explicit control rules applied by an LR(1) parser. The resulting system (Anon) integrates bottom-up and top-down processing strategies within a single, flexible framework modeled on the human perceptual cycle. Anon's structure and operation are described and discussed, and examples of its interpretation of real mechanical drawings are shown.
Computers and health&mdash;issues and protective measures
Authors: Kimberly H. Updegrove, Daniel A. Updegrove
Venue: ACM SIGUCCS Newsletter (1991)

Within the past year, substantial media attention has been directed at the potential adverse health effects of long-term computer use. Unfortunately, long-term effects require long-term studies, and much research in this area is either incomplete or inconsistent. Nevertheless, because so many Penn staff, faculty, and students are spending an increasing amount of time---both on campus and at home---working with keyboards and video display terminals (VDTs), and because some health effects are thought to be cumulative, we believe it is important for all computer users, lab managers, and supervisors to be aware of these issues and the protective measures that can be taken "while the jury is out."
Executing DSP Applications in a Fine-Grained Dataflow Environment
Authors: Ivan P. Radivojevic, Jayantha Herath
Venue: IEEE Transactions on Software Engineering (1991)

An experimental approach is chosen to investigate the performance of a fine-grained dataflow architecture for numerically intensive digital signal processing (DSP) applications. The focus is on the behavior of pipelined data-parallel algorithms. However, the granularity of the high-level language programming blocks is not explicitly optimized to balance computation and communication; a natural and logical fine-grained decomposition of problems is used instead. The authors interpret their empirical data by means of parameters such as a number of instructions per generic unit of computation, a density of precedence relations, and a serial fraction. The performance and limitations of fine-grained general-purpose dataflow computing are discussed.
Opportunities in the US from NSF, DARPA, and NASA
Authors: Marianne Winslett
Venue: ACM SIGMOD Record (1992)

In this issue, we begin with general information about the High Performance Computing and Communications (HPCC) Program at NSF, followed by a more focused look at HPCC work in the database area, and a close-up of the new scientific databases initiative. A NASA program for intelligent systems, DARPA programs in 3-D visualization and multiple knowledge sources, news of recent events at DARPA, and two new small business solicitations round out the funding news for this issue.
Performance Measurement and Modeling to Evaluate Various Effects on a Shared memory Multiprocessor
Authors: Xiaodong Zhang
Venue: IEEE Transactions on Software Engineering (1991)

Shared-memory multiprocessor performance is strongly affected by factors such as sequential code, barriers, cache coherence, virtual memory paging, and the multiprocessor system itself with resource scheduling and multiprogramming. Several timing models and analysis for these effects are presented. A modified Ware model based on these timing models is given to evaluate comprehensive performance of a shared-memory multiprocessor. Performance measurement has been done on the Encore Multimax, a shared-memory multiprocessor. The evaluation models are the analyses based on a general shared-memory multiprocessor system and architecture and can be applied to other types of shared-memory multiprocessors. Analytical and experimental results give a clear understanding of the various effects and a correct measure of the performance, which are important for the effective use of a shared-memory multiprocessor.
A functional model for macro-databases
Authors: M. Rafanelli, F. L. Ricci
Venue: ACM SIGMOD Record (1991)

Recently there have been numerous proposals aimed at correcting the deficiency in existing database models to manipulate macro data (such as summary tables). The authors propose a new functional model, Mefisto, based on the definition of a new data structure, the &ldquo;statistical entity&rdquo;, and on a set of operations capable of manipulating this data structure by operating at metadata level.
Mazes in disguise
Authors: D. Goodman
Venue: ACM SIGSMALL/PC Notes (1990)

Mazes are fun. Their appeal stems from their simplicity, their relevance to everyday problem solving, and their beauty. This article will give a simple algorithm by which interesting random mazes can be generated.
The EACM code performance Anomaly detector
Authors: David A. Rosenfeld, Gregory G. Allen
Venue: Proceedings of the eighth annual Washington Ada symposium summer SIGAda meeting on Ada: software: foundation for competitveness (1991)

Performance Anomalies, segments of a program which demand many more computational resources than the source code implies, are inevitable results of high-level languages and software engineering techniques. The Code Performance Anomaly Detector (CPAD) is a software agent which runs as part of the EACM (Expert Avionics Code Modification) Environment, a system specifically designed to aid software maintenance. This paper outlines the architecture of EACM, and describes the design of the CPAD as an agent within the overall system.
An experiment to determine software reusability factors (abstract)
Authors: John A. Lewis
Venue: Proceedings of the 1990 ACM annual conference on Cooperation (1990)

Software reusability has been proclaimed as the common sense solution to many software development problems. The concept of reusability promotes productivity because it avoids &ldquo;reinventing the wheel.&rdquo; Using existing components which are similar to the current needs can be much faster than creating components from scratch. Reusability can also be viewed as promoting reliability since reused components have the benefit of both experimental and field testing. However, reusability has not fulfilled its potential for revolutionizing the software development industry. Identifying the factors which cause current reuse efforts to fail is essential to its later success. Likewise, identifying the factors that seem to promote successful reusability is equally important. Furthermore, practical ways to eliminate the detrimental factors must be developed. An experiment designed to ferret out the causes of software reuse success and failure must consider several important issues: (1) The experiment must consist of actual development and reuse. Questionnaires and subjective measurements about whether to reuse, etc. are necessary but not sufficient. (2) The experiment must be greatly controlled to avoid extraneous factors from skewing the results. Factors which might influence the outcome must be deliberately tested for, or controlled such that they do not bias the experimental data. (3) The components to be reused must be determined. Reusing requirements and designs has been suggested, but with little success. On the other hand, reusing test cases has been greatly successful. In between is code. Current experiments should still concentrate on the ability to reuse source code. You must walk before you run. (4) Finally, the factors being tested must be established and they must consider two main tangents. First, specific factors concerning the code characteristics, the organization of components, and the development environment must be considered. Other concerns deal with the human factors. Predisposition, ego, training and skill must be taken into account for an accurate study of reusability. A current reusability experiment concentrates on the use of an object-oriented organization scheme, reusable code characteristics, and several human factors. The experimental subjects actually design and implement code under varying conditions. Subjects are divided into groups that must reuse whenever possible, may reuse if desired, and cannot reuse at all. Comparing the results of the various groups will lead to a better understanding of the problems faced in software reusability.
Problems with Pthreads and Ada
Authors: Offer Pazy
Venue: ACM SIGAda Ada Letters (1990)

This position paper discusses issues related to the recent effort to add real-time extensions to the posix (1003.1 |3|) standard, and in particular to the proposal for light-weight tasking in the form of pthreads |2|. It is claimed that this effort is relevant to the Ada community, especially in the real-time domain. While offering great opportunities to improve the performance of multi-tasking, real-time Ada applications, it may become not useful if the semantics of the specifications are not thought about very carefully, and the match with Ada requirements is not satisfied. Due to certain problems with the proposal as it stands now, it is suggested that the workshop take a close look at the draft, evaluate it, and decide on a plan of action to guarantee the suitability of pthreads to real-time Ada applications before it is approved as a standard.
Back to direct style II: first-class continuations
Authors: Olivier Danvy, Julia L. Lawall
Venue: Proceedings of the 1992 ACM conference on LISP and functional programming (1992)

We continue to investigate the direct-style transformation by extending it to programs requiring call-with-current-continuation (a.k.a. call/cc). The direct style (DS) and the continuation-passing style (CPS) transformations form a Galois connection. This pair of functions has a place in the programmer's toolbox&mdash;yet we are not aware of the existence of any other DS transformer. Starting from our DS transformer towards pure, call-by-value functional terms (Scheme), we extend it with a counting analysis to detect non-canonical occurrences of a continuation. The declaration of such a continuation is translated into a call/cc and its application into the application of the corresponding first-class continuation We also present staged versions of the DS and of the CPS transformations, where administrative reductions are separated from the actual translation, and where the actual translations are carried out by local, structure-preserving rewriting rules. These staged transformations are used to prove the Galois continuation. Together, the CPS and the DS transformations enlarge the class of programs that can be manipulated on a semantic basis. We illustrate this point with partial evaluation, by specializing a Scheme program with respect to a static part of its input. The program uses coroutines. This illustration achieves a first: a static coroutine is executed statically and its computational content is inlined in the residual program.
Permutation group algorithms based on partitions, I: Theory and algorithms
Authors: Jeffrey S. Leon
Venue: Journal of Symbolic Computation (1991)

A technique for computing in permutation groups of high degree is developed. The technique uses the idea of successive refinement of ordered partitions, introduced by B. McKay in connection with the graph isomorphism problem, to supplement the techniques of base and strong generating set developed earlier by Sims. Applications to a number of specific problems in computational group theory are presented.
Analysis of directory based cache coherence schemes with multistage networks
Authors: Ashwini K. Nanda, Hong Jiang
Venue: Proceedings of the 1992 ACM annual conference on Communications (1992)

Designing efficient cache coherence schemes for shared memory multiprocessors has attracted much attention of the researchers in the area. Snoopy cache protocols have been designed for bus based multiprocessors. However, the snoopy protocols are not applicable to general interconnection networks. On the other hand, the directory based cache protocols adapt very well to any kind of interconnection network such as a Multistage Network. Since different protocols have different cost overheads, and may give different performance, the protocol to be used must be wisely selected. Although there has been some simulation studies on the behavior of different directory schemes proposed in the literature, there has been no systematic analytical model for these schemes. In this paper we develop a detailed analytical model of the various directory schemes on a Multistage Interconnection Network. The shared miss ratios are computed analytically, and the performance of the various schemes is compared. Results are presented to show that the directories do not form a system bottleneck contrary to popular belief.
Surfaces from contours
Authors: David Meyers, Shelley Skinner, Kenneth Sloan
Venue: ACM Transactions on Graphics (TOG) (1992)

This paper is concerned with the problem of reconstructing the surfaces of three-dimensional objects, given a collection of planar contours representing cross-sections through the objects. This problem has important aplications in biomedical research and instruction, solid modeling, and industrial inspection. The method we describe produces a triangulated mesh from the data points of the contours which is then used in conjunction with a piecewise parametric surface-fitting algorithm to produce a reconstructed surface. The problem can be broken into four subproblems: the correspondence problem (which contours should be connected by the surface?), the tiling problem (how should the contours be connected?), the branching problem (what do we do when there are branches in the surface?), and the surface-fitting problem (what is the precise geometry of the reconstructed surface?) We describe our system for surface reconstruction from sets of contours with respect to each of these subproblems. Special attention is given to the correspondence and branching problems. We present a method that can handle sets of contours in which adjacent contours share a very contorted boundary, and we describe a new approach to solving the correspondence problem using a Minimum Spanning Tree generated from the contours.
Remembering Allen Newell
Authors: Stuart Card, Thomas Moran, George Robertson
Venue: ACM SIGCHI Bulletin (1992)

Allen Newell, one of the founders of the fields of artificial intelligence, cognitive science, and human-computer interaction, died July 19 in Pittsburgh. He was 65.
The weighted region problem: finding shortest paths through a weighted planar subdivision
Authors: Joseph S. B. Mitchell, Christos H. Papadimitriou
Venue: Journal of the ACM (JACM) (1991)

The problem of determining shortest paths through a weighted planar polygonal subdivision with n vertices is considered. Distances are measured according to a weighted Euclidean metric: The length of a path is defined to be the weighted sum of (Euclidean) lengths of the subpaths within each region. An algorithm that constructs a (restricted) &ldquo;shortest path map&rdquo; with respect to a given source point is presented. The output is a partitioning of each edge of the subdivion into intervals of &egr;-optimality, allowing an &egr;-optimal path to be traced from the source to any query point along any edge. The algorithm runs in worst-case time O(ES) and requires O(E) space, where E is the number of &ldquo;events&rdquo; in our algorithm and S is the time it takes to run a numerical search procedure. In the worst case, E is bounded above by O(n4) (and we give an &OHgr;(n4) lower bound), but it is likeky that E will be much smaller in practice. We also show that S is bounded by O(n4L), where L is the precision of the problem instance (including the number of bits in the user-specified tolerance &egr;). Again, the value of S should be smaller in practice. The algorithm applies the &ldquo;continuous Dijkstra&rdquo; paradigm and exploits the fact that shortest paths obey Snell's Law of Refraction at region boundaries, a local optimaly property of shortest paths that is well known from the analogous optics model. The algorithm generalizes to the multi-source case to compute Voronoi diagrams.
Speech understanding and dialouge over the telephone: an overview of the ESPRIT SUNDIAL
Authors: Jeremy Peckham
Venue: Proceedings of the workshop on Speech and Natural Language (1991)

One of the most obvious and natural applications for speech technology is in providing a gateway to information services over the telephone network. Already a significant growth is occurring the provision of information from a centralised computing system using stored messages or synthetic speech derived from text files. Most of these systems however currently rely on the use of touch tone input for selection of the information. In the UK only 15% of homes and businesses have tone dialling, although the network is currently able to support around 50% tone dialling. The ability to recognise a small number of words or even the digits without the user requiring to train the system therefore has widespread application. As the scope of the information service expands so also does the need for more intelligent dialogues with much larger vocabularies for speech understanding.
Explicit solutions to the N-queens problem for all N
Authors: Bo Bernhardsson
Venue: ACM SIGART Bulletin (1991)

The n-queens problem is often used as a benchmark problem for AI research and in combinatorial optimization. An example is the recent article [1] in this magazine that presented a polynomial time algorithm for finding a solution. Several CPU-hours were spent finding solutions for some n up to 500,000.
Tachyon Common Lisp: an efficient and portable implementation of CLtL2
Authors: Atsushi Nagasaka, Yoshihiro Shintani, Tanji Ito, Hiroshi Gomi, Junichi Takahashi
Venue: Proceedings of the 1992 ACM conference on LISP and functional programming (1992)

Tachyon Common Lisp is an efficient and portable implementation of Common Lisp 2nd Edition. The design objective of Tachyon is to apply both advanced optimization technology developed for RISC processors and Lisp optimization techniques. The compiler generates very fast codes comparable to, and sometimes faster than the code generated by UNIX C compiler. Comparing with the most widely used commercial Common Lisp, Tachyon Common Lisp compiled code is 2 times faster and the interpreter is 6 times faster than the Lisp in Gabriel benchmark suit. Tachyon Common Lisp is the fastest among the Lisp systems known to the authors.
On constructing binary space partitioning trees
Authors: Ravinder Krishnaswamy, Ghasem S. Alijani, Shyh-Chang Su
Venue: Proceedings of the 1990 ACM annual conference on Cooperation (1990)

Binary Space Partitioning Trees have several applications in computer graphics. We prove that there exist n-polygon problem instances with an O(n2) lower bound on tree size. We also show that a greedy algorithm may result in constructing a tree with O(n2) nodes, while there exist a tree for the same n-polygon instance with only O(n) nodes. Finally, we formulate six different heuristics and test their performance.
Exact learning of read-k disjoint DNF and not-so-disjoint DNF
Authors: Howard Aizenstein, Leonard Pitt
Venue: Proceedings of the fifth annual workshop on Computational learning theory (1992)

A polynomial-time algorithm is presented for exactly learning the class of read-k disjoint DNF formulas&mdash;boolean formulas in disjunctive normal form where each variable appears at most k) and every assignment to the variables satisfies at most one term of F. The (standard) protocol used allows the learning algorithm to query whether a given assignment of boolean variables satisfies the DNF formula to be learned (membership queries), as well as to obtain counterexamples to the correctness of its current hypothesis which can be any arbitrary DNF formula (equivalence queries). The formula output by the learning algorithm is logically equivalent to the formula to be learned. We show that this result also applies for a generalization of read-k disjoint DNF which we call read-k sat-j DNF; these are DNF formulas in which every variable appears at most k times and every assignment satisfies at most j terms.
An Ada math library for real-time avionics
Authors: Donald A. Celarier, Donald W. Sando
Venue: ACM SIGAda Ada Letters (1991)

This paper describes an ideal Ada math library for use in embedded, real-time avionics, and a library implementation based on this model for a "standard" military avionics processor. The special requirements and implementation considerations for avionics applications are discussed, and the design and specification of an Ada math library closely matching these stringent requirements is put forward. Evaluation procedures are briefly discussed, including new techniques for accuracy testing without requiring higher precision.