ppxscal/embedding_network huggingface dataset:
Illustrating interference in interfering versions of programs
Authors: T. Reps, T. Bricker
Venue: ACM SIGSOFT Software Engineering Notes (1989)

The need to integrate several versions of a program into a common one arises frequently, but it is a tedious and time consuming task to merge programs by hand. The program-integration algorithm recently proposed by S. Horwitz, J. Prins, and T. Reps provides a way to create a semantics-based tool for program integration. The integration algorithm is based on the assumption that any change in the behavior, rather than the text, of a program variant is significant and must be preserved in the merged program. An integration system based on this algorithm will determine whether the programs incorporate interfering changes, and, if they do not, will automatically create an integrated program that includes all changes as well as all features that are preserved in all variants. In this paper we discuss how an integration tool can illustrate the causes of interference to the user when interference is detected. Our main technical result is an alternative characterization of the integration algorithm's interference criterion that is more suitable for illustrating the causes of interference. We then propose six methods for an integration system to display information to demonstrate the causes of interference to the user.
Systolic Evaluation of Polynomial Expressions
Authors: P. C. Mathias, L. M. Patnaik
Venue: IEEE Transactions on Computers (1990)

Two types of organizations are presented for frame buffers of m*m pixels: one is a single wavefront complex cell array requiring O(m/sup 2/n) space and the other is a simple cell multiple wavefront array with O(m/sup 2/) area and O(n/sup 2/) wavefronts. Both these organizations have two main advantages over an earlier method: the cells and the interconnection among them are regular and hence are suitable for efficient VLSI implementation, and the organization permits evaluation of higher-order polynomials.
Solving equations nonlinear in only one of N + 1 variables
Authors: Charles B. Dunham, C. Z. Zhu
Venue: ACM SIGNUM Newsletter (1988)

Equations linear in n out of n + 1 variables can be solved by reduction to a linear subproblem and variation of the nonlinear parameter.
Type of service wide area networking
Authors: J. Lekashman
Venue: Proceedings of the 1989 ACM/IEEE conference on Supercomputing (1989)

There are a variety of long distance types of circuits that can be used for data communication. This paper describes an experiment which optimizes the simultaneous use of terrestrial and satellite circuits in a TCP/IP network. Traditionally, there have been problems effectively using the full capacity of high bandwidth satellite circuits, due to long round trip times coupled with TCP window-size limitations. The experiment significantly reduced the problem, and the result was effective use of all the available bandwidth of a satellite circuit for a single data transfer. This experiment also demonstrates the use of multiple T1 communication lines, and type of service networking over these lines.
Global microcode compaction under timing constraints
Authors: B. Su, J. Wang, J. Xia
Venue: Proceedings of the 21st annual workshop on Microprogramming and microarchitecture (1988)

Existing global microcode compaction algorithms have all been based on the assumption that the parallelism exploitation is constrained only by data dependency and resource limitation. However, the timing constraint also has great impact upon microcode compaction, thus it is highly necessary to study global microcode compaction under timing constraints. This paper conducts an analysis on the global timing problem, modifies the MO motion rules and presents an algorithm based on Trace Scheduling for global microcode compaction under timing constraints.
A cognitively valid knowledge acquisition tool
Authors: J. S. Lancaster, C. R. Westphal, K. L. McGraw
Venue: Issue 108 (April 1989) (1989)

As more (and more) knowledge-based systems are designed for operational use, it becomes apparent that the knowledge engineering (KE) process of transferring domain expertise into the system consumes the single largest block of development time (Feigenbaum, 1977; Hayes-Roth, Waterman, amp; Lenat, 1983). To reduce the time required for this stage, numerous tools have been developed that automate or systematize the elicitation and transfer of knowledge from expert to knowledge base. Among these advances are developments in machine learning that enable an expert system to acquire its knowledge from "experience" (Michalski, 1980; Michie, 1982), expert system shells that allow domain experts to write their own rules (e.g., MacSMARTS), and knowledge engineering tools that assist a knowledge engineer in his/her work. The material reported here describes BDM's development of a computer-based set of tools, known collectively as BDM-KAT.
Practical algorithms for finding prime attributes and testing normal forms
Authors: H. Mannila, K.-J. Raiha
Venue: Proceedings of the eighth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems (1989)

Several decision problems for relational schemas with functional dependencies are computationally hard. Such problems include determining whether an attribute is prime and testing if a schema is in normal form. Algorithms for these problems are needed in database design tools. The problems can be solved by trivial exponential algorithms. Although the size of the instance is usually given by the number of attributes and hence is fairly small, such exponential algorithms are not usable for all design tasks. We give algorithms for these problems whose running time is polynomial in the number of maximal sets not determining an attribute or, equivalently, the number of generators of the family of closed attribute sets. There is theoretical and practical evidence that this quantity is small for the schemas occurring in practice and exponential only for pathological schemas. The algorithms are simple to implement and fast in practice. They are in use in the relational database design tool Design-By-Example.
An exercise in deriving a protocol conversion
Authors: K. L. Calvert, S. S. Lam
Venue: Proceedings of the ACM workshop on Frontiers in computer communications technology (1987)

This paper demonstrates formal techniques useful in solving and reasoning about protocol conversion problems. A simple example problem is solved and the resulting conversion system is shown to have certain desired properties, using the projection paradigm. The example problem is representative of some real-world problems in that the protocols involved are similar in function, and even in structure, but have fundamental differences that render them incompatible in the absence of an active translation entity (protocol converter). The use of mappings, as well as images and inverse images of properties, in comparing semantics of protocols is discussed and illustrated.
The selection of an Ada compiler for a real-time embedded avionics application
Authors: R. Davis
Venue: Proceedings of the conference on Tri-Ada '89: Ada technology in context: application, development, and deployment (1989)

This paper addresses the selection of an Ada cross-compiler, run-time system, and associated tools from a VAX/VMS1host to a Mil-Std-1750A target processor (DOD79). The selection process was performed as part of a proposal for an airborne embedded, multi-tasking avionics application which is scheduled to enter the requirements phase in the fall of 1989. A previous project, the GPSDR (Global Positioning Software Demonstration Receiver) Navigation Software for the TOPEX (Topographical Experiment) / Poseidon satellite, also involved the coding of Ada for a Mil-Std-1750A application from a VAX/VMS host. That project also included a thorough evaluation of the VAX/1750 cross-compilers for Ada and C (DAVIS88) that were available at that time (the fall of 1987). That compiler evaluation and completion of that project therefore contributed to this compiler evaluation. The GPSDR software was also real-time embedded software (which in that case executed on a satellite), so that project was comparable in many ways to the this software project. The compiler comparison results documented here are different from the compiler selection for the GPSDR, because this analysis was performed a year after the TOPEX GPSDR compiler analysis, and the cross-compilers studied have matured substantially in that year. The TOPEX GPSDR effort indicated that Ada can be used for an embedded application with real-time memory and throughput requirements. Assembly language code was necessary only for the ROM area. Although of concern, memory and throughput did not have as tremendous an impact on the design and implementation of the GPSDR as they have had on other Ada embedded projects. That was primarily because of the care with which the cross-compiler selection was made.
Properties and update semantics of consistent views
Authors: Georg Gottlob, Paolo Paolini, Roberto Zicari
Venue: ACM Transactions on Database Systems (TODS) (1988)

The problem of translating view updates to database updates is considered. Both databases and views are modeled as data abstractions. A data abstraction consists of a set of states and of a set of primitive update operators representing state transition functions. It is shown how complex update programs can be built from primitive update operators and how view update programs are translated into database update programs. Special attention is paid to a class of views that we call &ldquo;consistent.&rdquo; Loosely speaking, a consistent view is a view with the following property: If the effect of a view update program on a view state is determined, then the effect of the corresponding database update is unambiguously determined. Thus, in order to know how to translate a given view update into a database update, it is sufficient to be aware of a functional specification of such a program. We show that consistent views have a number of interesting properties with respect to the concurrency of (high-level) update transactions. Moreover we show that the class of consistent views includes as a subset the class of views that translate updates under maintenance of a constant complement. However, we show that there exist consistent views that do not translate under constant complement. The results of Bancilhon and Spyratos [6] are generalized in order to capture the update semantics of the entire class of consistent views. In particular we show that the class of consistent views is obtained if we relax the requirement of a constant complement by allowing the complement to decrease according to a suitable partial order.
Treating failure as value
Authors: L. Wong, B. C. Ooi
Venue: ACM SIGPLAN Notices (1990)

Two's complement notation is a popular binary numeral representation of integers. However, this representation is asymmetric and partial. The consequences are complications like overflowing and underflowing. We try to re-interpret the asymmetry of two's complement numbers to provide a better representation of integers. Our effort leads us to consider the treatment of failure as value rather than as state. The result of this approach goes beyond the solution of our original problem and gives rise to a rather elegant treatment of failure.
A real-time expert system for computer network monitor and control
Authors: Barton B. Dunning, John Switlik
Venue: ACM SIGMIS Database (1988)

SEMACS is a continuous, real-time expert monitor and control system that actively and passively monitors a computer network. It detects and diagnoses hardware and software problems with the network and provides advice and solutions to anoperator in his domain of influence. It was developed jointly by Sperry and one of its customers during an Expert Systems Apprenticeship with the Sperry Knowledge Systems Center. The prototype system, which includes all major components of the final, operational system, was developed over a period of six weeks, and an operational system was put on-line within 3 months of starting the project.
Array Access Bounds for Block Storage Memory Systems
Authors: A. Park, K. Balasubramanian, R. J. Lipton
Venue: IEEE Transactions on Computers (1989)

Paging performance can be a dominant factor in a program's running time. Many seemingly efficient data structures and algorithms lose orders of magnitude in performance because they generate an excessive number of page faults. This study shows that tradeoffs exist between average row access speed S/sub r/ (which is defined as the number of row elements retrieved divided by the number of blocks accessed) and average column access speed S/sub c/ (defined similarly). The authors prove that the S/sub r/S/sub c/ product is optimally bounded by the block size N and generalize to other access patterns. Practical array access strategies are developed, and extensions to these results are discussed.
Programmable execution of multi-layered networks for automatic speech recognition
Authors: Y. Bengio, R. Cardin, R. De Mori, E. Merlo
Venue: Communications of the ACM (1989)

A set of Multi-Layered Networks allows the integration of information extracted with variable resolution in the time and frequency domains and to keep the number of links between nodes of the networks small for significant generalization during learning with a reasonable training set size.
Beyond striping: the bridge multiprocessor file system
Authors: P. C. Dibble, M. L. Scott
Venue: ACM SIGARCH Computer Architecture News (1989)

High-performance parallel computers require high-performance file systems. Exotic I/O hardware will be of little use if file system software runs on a single processor of a many-processor machine. We believe that cost-effective I/O for large multiprocessors can best be obtained by spreading both data and file system computation over a large number of processors and disks. To assess the effectiveness of this approach, we have implemented a prototype system called Bridge, and have studied its performance on several data intensive applications, among them external sorting. A detailed analysis of our sorting algorithm indicates that Bridge can profitably be used on configurations in excess of one hundred processors with disks. Empirical results on a 32-processor implementation agree with the analysis, providing us with a high degree of confidence in this prediction. Based on our experience, we argue that file systems such as Bridge will satisfy the I/O needs of a wide range of parallel architectures and applications.
A Shape From Shading Analysis for a Single Perspective Image of a Polyhedron
Authors: M. A. Penna
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1989)

A shape-from-shading analysis for a single perspective image of a polyhedron is presented. Given a single perspective image of a polyhedron, the depth of any point of the polyhedron from the camera, the direction of the light source illuminating the polyhedron and the albedo of the polyhedron, a system of algebraic equations are derived, which, when combined with edge information, quantitatively describes the shape of the polyhedron. This analysis is best possible in the sense that if any component of what the author has assumed is omitted, no similar analysis can provide the same results.
Large-scale parallel programming: experience with BBN butterfly parallel processor
Authors: Thomas J. LeBlanc, Michael L. Scott, Christopher M. Brown
Venue: Proceedings of the ACM/SIGPLAN conference on Parallel programming: experience with applications, languages and systems (1988)

For three years, members of the Computer Science Department at the University of Rochester have used a collection of BBN Butterfly&trade; Parallel Processors to conduct research in parallel systems and applications. For most of that time, Rochester's 128-node machine has had the distinction of being the largest shared-memory multiprocessor in the world. In the course of our work with the Butterfly we have ported three compilers, developed five major and several minor library packages, built two different operating systems, and implemented dozens of applications. Our experience clearly demonstrates the practicality of large-scale shared-memory multiprocessors, with non-uniform memory access times. It also demonstrates that the problems inherent in programming such machines are far from adequately solved. Both locality and Amdahl's law become increasingly important with a very large number of nodes. The availability of multiple programming models is also a concern; truly general-purpose parallel computing will require the development of environments that allow programs written under different models to coexist and interact. Most important, there is a continuing need for high-quality programming tools; widespread acceptance of parallel machines will require the development of programming environments comparable to those available on sequential computers.
Electron beam testing in Japan
Authors: Hiromu Fujioka, Katsumi Ura
Venue: Microelectronic Engineering (1988)

This paper summarizes some recent topics of electron beam testing in Japan: voltage contrast techniques, EB tester systems, measurement of microstructures, and automatic control of the electron optical column.
A Note Extending the Analysis of Two-Head Disk Systems to More General Seek-Time Characteristics
Authors: A. R. Calderbank, E. G. Coffman,  Jr., L. Flatto
Venue: IEEE Transactions on Computers (1989)

The authors analyze a model of a movable-head disk system with two read/write heads maintained a fixed distance d apart on each arm. Successive request-addresses are assumed to be independent random variables, uniformly distributed over the set of cylinders. The purpose of the analysis is to find that value of d which minimizes the expected seek time per request, assuming that seek time varies linearly with the distance z traveled by the heads. The authors extend an earlier analysis of this model to more general seek-time characteristics which take into account nonlinear acceleration effects. Detailed results, combining both analysis and simulation experiments, are presented for seek times linear in z/sup alpha /, 0>or= alpha >or=1. An unexpected result of the study was that the value of d which minimizes expected seek time is very nearly independent of alpha.
Performance evaluation of programs for the error and complementary error functions
Authors: W. J. Cody
Venue: ACM Transactions on Mathematical Software (TOMS) (1990)

This paper presents methods for performance evaluation of computer programs for the functions erf(x), erfc(x), and ex2 erfc(x). Accuracy estimates are based on comparisons using power series expansions and an expansion in the repeated integrals of erfc(x). Some suggestions for checking robustness are also given. Details of a specific implementation of a test program are included.
Accurate and efficient testing of the exponential and logarithm functions
Authors: Ping-Tak Peter Tang
Venue: ACM Transactions on Mathematical Software (TOMS) (1990)

Table-driven techniques can be used to test highly accurate implementation of EXP LOG. The largest error observeed in EXP and LOG accurately to within 1/500 unit in the last place are reported in our tests. Methods to verify the tests' reliability are discussed. Results of applying the tests to our own as well as to a number of other implementations of EXP and LOG are presented.
A case for redundant arrays of inexpensive disks (RAID)
Authors: David A. Patterson, Garth Gibson, Randy H. Katz
Venue: Proceedings of the 1988 ACM SIGMOD international conference on Management of data (1988)

Increasing performance of CPUs and memories will be squandered if not matched by a similar performance increase in I/O. While the capacity of Single Large Expensive Disks (SLED) has grown rapidly, the performance improvement of SLED has been modest. Redundant Arrays of Inexpensive Disks (RAID), based on the magnetic disk technology developed for personal computers, offers an attractive alternative to SLED, promising improvements of an order of magnitude in performance, reliability, power consumption, and scalability. This paper introduces five levels of RAIDs, giving their relative cost/performance, and compares RAID to an IBM 3380 and a Fujitsu Super Eagle.
Conversational hypertext: information access through natural language dialogues with computers
Authors: T. Whalen, A. Patrick
Venue: ACM SIGCHI Bulletin (1989)

One need not create a natural language understanding system in order to create a hypertext data base that can be traversed with unconstrained natural language. The task is simplified because the computer creates a constrained context, imposes a non-negotiable topic, and elicits simple questions. Two small hypertext data bases describing the authors' organization and the terms and rules of baseball were implemented on an IBM PC. When ten untrained people were allowed to search through these data bases, 59 per cent of their queries were answered correctly by the first data base and 64 per cent by the second.
Parallel execution of sequential scheme with ParaTran
Authors: Pete Tinker, Morry Katz
Venue: Proceedings of the 1988 ACM conference on LISP and functional programming (1988)

This paper describes a system called ParaTran for executing sequential Scheme in parallel. It supports arbitrary side effects without requiring user annotations. The ParaTran runtime system detects and corrects data dependency violations using an automatic history and rollback mechanism. ParaTran is first described by analogy with Time Warp, a system for distributed simulation; this description is followed by a discussion of ParaTran's implementation and presentation of preliminary results.
Synthesis of Mutual Exclusion Solutions Based on Binary Semaphores
Authors: R. T. Jacob, I. P. Page
Venue: IEEE Transactions on Software Engineering (1989)

A graphical form of the mutual exclusion problem is considered in which each vertex represents a process and each edge represents a mutual exclusion constraint between the critical sections of the processes associated with its endpoints. An edge semaphore solution for mutual exclusion problems is defined, and those graphs which are edge solvable are characterized in terms of both a forbidden subgraph and a graph grammar. Finally, an efficient algorithm is given which generates the entry and exit sections for all processes in an edge-solvable problem.
An implementation of standard ML modules
Authors: David MacQueen
Venue: Proceedings of the 1988 ACM conference on LISP and functional programming (1988)

Standard ML includes a set of module constructs that support programming in the large. These constructs extend ML's basic polymorphic type system by introducing the dependent types of Martin L&ouml;f's Intuitionistic Type Theory. This paper discusses the problems involved in implementing Standard ML's modules and describes a practical, efficient solution to these problems. The representations and algorithms of this implementation were inspired by a detailed formal semantics of Standard ML developed by Milner, Tofte, and Harper. The implementation is part of a new Standard ML compiler that is written in Standard ML using the module system.
Finding the Optimal Variable Ordering for Binary Decision Diagrams
Authors: S. J. Friedman, K. J. Supowit
Venue: IEEE Transactions on Computers (1990)

The ordered binary decision diagram is a canonical representation for Boolean functions, presented by R.E. Bryant (1985) as a compact representation for a broad class of interesting functions derived from circuits. However, the size of the diagram is very sensitive to the choice of ordering on the variables; hence, for some applications, such as differential cascode voltage switch (DCVS) trees, it becomes extremely important to find the ordering leading to the most compact representation. An algorithm for this problem with time complexity O(n/sup 2/3/sup n/) is presented. This represents an improvement over the previous best algorithm.