ppxscal/embedding_network huggingface dataset:
Storing and searching a multikey table
Authors: Amos Fiat, Moni Naor, Alexandro Schäffer, Jeanette Schmidt, Alan Siegel
Venue: Proceedings of the twentieth annual ACM symposium on Theory of computing (1988)

We describe an implicit data structure for n multikey records that supports searching for a record, under any key, in the asymptotically optimal search time &Ogr;(log n). This improves on [Mun87] in which Munro describes an implicit data structure for the problem of storing n k-key records so that search on any key can be performed in &Ogr;(logk n(log log n)k-1) comparisons. The theoretical tools we develop also yield practical schemes that either halve the number of memory references over obvious solutions to the non-implicit version of the problem, or alternatively reduce the number of pointers involved significantly.
Symbolic computation of hyperbolicity regions for systems of two-phase flow conservation laws using Maple
Authors: A. D. Fitt
Venue: Journal of Symbolic Computation (1989)

Symbolic algebra packages have recently been making a large impact on both pure and appliedmathematical research. In this study, an application of the symbolic manipulation system MAPLE to the mathematical modelling of multiphase flows is discussed. The physical modelling problem is an extremely hard one, and there is little consensus on the correct form of the governing equations for such flows. Moreover, many such sets of equations are ill-posed in the sense that they admit complex eigenvalues (wave speeds). A procedure has been written in MAPLE command language to examine a set of partial differential equations to determine their character (elliptic, hyperbolic or parabolic). Previously, for many systems this computation could take so long that it was unrealistic to attempt. Now however such calculations may be made so quckly that it is possible to undertake parametric studies of the equations in order to improve basic modelling techniques.
How a SIMD machine can implement a complex cellular automata? a case study: von Neumann's 29-state cellular automaton
Authors: J. Signorini
Venue: Proceedings of the 1989 ACM/IEEE conference on Supercomputing (1989)

This study is a part of an effort to simulate the 29-state self-reproducing cellular automaton described by John von Neumann in a manuscript that dates back to 1952. We are interested in the programming of very large SIMD arrays which, as a consequence of scaling them up, incorporate some features of cellular automata. Designing tools for programming them requires an experimental ground: considering that von Neumann's 29-state is the only known very large and complex cellular automaton, its simulation is a necessary first step. Embedded in a two-dimensional cellular array, using 29 states per cell and 5-cell neighborhood, this automaton exhibits the capabilities of universal computation and universal construction. This paper concentrates on the transition rule that governs the complex behavior of the 29-state automaton. We give a detailed presentation of its transition rule, with illustrative examples to ease its comprehension. We then discuss its implementation on a SIMD machine, using only 13 bits per processing element to encode the rule, each processing element corresponding to a cell. Finally, we present experimental results based upon the simulation of general-purpose components of the automaton: pulser, decoder, periodic pulser on the SIMD machine.
Using current literature in two courses
Authors: Robert A. Hovis
Venue: ACM SIGCSE Bulletin (1988)

In any computer science program, it is important to spend a large amount of time teaching students about the fundamental topics at the core of computer science. Everyone also acknowledges that certain topics in mathematics are essential. This paper deals with two other problems and how they can be handled. The two problems are keeping abreast of current issues in computer science and developing writing skills. I have identified two courses in the core curriculum where it is especially useful to treat these problems.
Dynamic distributed query processing techniques
Authors: P. Bodorik, J. S. Riordon, C. Jacob
Venue: Proceedings of the 17th conference on ACM Annual Computer Science Conference (1989)

As optimization of strategies to process queries in a Distributed DataBase (DDB) uses various techniques to estimate the sizes of partial results and other parameters pertaining to the distributed environment, if these estimates are inaccurate the strategies may be far from optimal. Dynamic query execution, which may be used to alleviate this problem, is examined in this paper. Execution of a strategy is assumed to proceed through three phases: (i) monitoring phase in which processors monitor the progress of the strategy execution; (ii) decision making phase in which they may decide to correct the current strategy because it is not optimal due to inaccurate estimates used in its formulation; and (iii) corrective phase in which the current strategy is aborted and a new, corrective strategy is initiated. Methods applicable to each phase and their integration is examined in detail in terms of overhead, complexity and accuracy of information used in correcting a strategy.
Developing awareness of computer ethics
Authors: K. A. Forcht, J. K. Pierson, B. M. Bauman
Venue: Proceedings of the ACM SIGCPR conference on Management of information systems personnel (1988)

The most important factor in effective computer security is people&mdash;their attitudes, their actions, and their sense of right and wrong. This workshop will explore the ethical problems and issues raised in the computing environment. Topics to be discussed include misuse of computers, concepts of privacy, codes of conduct for computer professionals, disputed rights to products, defining ethical, moral, and legal parameters, and what security practitioners should do about ethics. Audience opinions will be welcome as they will aid in developing ethical standards for the information systems profession.
Updating an older interface
Authors: Marcy Telles
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems: Empowering people (1990)

Much of the research in the field of human/computer interface is aimed at the interface designer who begins from scratch. A different set of needs confronts the designer who must update an existing interface without throwing away the good elements of the old design and the knowledge base of experienced users. In this paper, the factors that contribute to the need for interface changes are presented, along with the special challenges that make change more difficult than new design. Approaches are suggested for dealing with the problems of updating an interface to make it effective for both old and new users.
A critical assessment of hypertext systems
Authors: G. Fischer, S. Weyer, W. P. Jones, A. C. Kay, W. Kintsch
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems (1988)

Over forty years ago, Vannevar Bush articulated his vision of a &ldquo;Memex&rdquo; machine: &ldquo;associative indexing, &hellip; whereby any item may be caused at will to select immediately and automatically another&rdquo; [Bush 45]. In the sixties, Engelbart [Engelbart, English 68] built collaborative systems to provide idea structuring and sharing. Nelson [Nelson 81] coined &ldquo;hypertext&rdquo; and proposed world-wide networks for publishing, linking, annotating and indexing multiple versions of documents. With increasing numbers of research projects, papers, panels and conferences, and commercially available systems (e.g. Notecards by Xerox, Guide by Owl and HyperCard by Apple) in recent years, hypertext may be an idea whose time has finally come &mdash; or at least a phenomenon not to be ignored. The goal of this panel is not to define hypertext or hypermedia (at its simplest: non-linearly arranged and accessed information), debate its uniqueness, explain implementation issues, or survey the many applications and contributions in the field (see [Conklin 87] for an excellent survey of Hypertext, and the Proceedings of Hypertext '87 Workshop at University of North Carolina, Chapel Hill). Rather, we intend to approach it from the perspective of the information user: reader, searcher, author. The panel will address the following issues: Are the processes of authoring and understanding helped or hindered by the non-linear structure of hypertext, for which kinds of tasks and users? What is the difference between a hypertext writer and a knowledge engineer? In searching for information, what is the difference between browsing and querying? What experiments need to be done? What tools, environment or interfaces can improve the process of information creation and access? Can the overhead of creating or interpreting structure be reduced? When will hypertext replace paper, or should it? How do functions of author and reader co-evolve? Could this revolutionize society like the printing press? Why didn't the panelists create a multi-versioned, highly crossreferenced online entry for the proceedings? Is hypertext a technology in search of a problem?
On Reliability Modeling of Closed Fault-Tolerant Computer Systems
Authors: M. Balakrishnan, C. S. Raghavendra
Venue: IEEE Transactions on Computers (1990)

It is observed that a large number of closed fault-tolerant systems modeled by a continuous-time Markov model referred to as the ARIES model have repeated eigenvalues. It is proven that the rate matrix representing the system is diagonalizable for every closed fault tolerant system modeled by ARIES. Consequently, the Lagrange-Sylvester interpolation formula is applicable to all closed fault-tolerant systems which ARIES models. Since the proof guarantees that the rate matrix is diagonalizable, general methods for solving arbitrary Markov chains can be tailored to solve the ARIES model for the closed systems directly.
Firmware approach to fast Lisp interpreter
Authors: H. G. Okuno, N. Osato, I. Takeuchi
Venue: ACM SIGMICRO Newsletter (1988)

Thc approach to speed up a Lisp interpreter by implementing it in firmware seems promising. A microcoded Lisp interpreter shows good performance for very simple benchmarks, while it often fails to provide good performance for larger benchmarks and applications unless speedup techniques are devised for it. This was the case for the TAO/ELIS system. This paper describes various techniques devised for the TAO/ELIS system in order to speed up the interpreter of the TAO language implemented on the ELIS Lisp machine. The technigues include data type dispatch, variable access, function call and so on. TAO is not only upward compatible with Common Lisp, but also incorporates logic programming. object-oriented programming and Fortran/C-like programming into Lisp programming. TAO also provides concurrent programming and supports multiple users (up to eight users). The TAO interpreter for those programming paradigms is coded fully in microcodes. In spite of rich functionalities, the speed of interpreted codes of TAO is comparable to that of compiled codes of commercial Lisp machines. Furthermore, the speeds of the interpreted codes of the same program written in various programming paradigms in TAO does not differ so much. This speed balance is very important for the user.Another outstanding feature of the TAO/ELIS system is its firmware development environments. Micro Assembler and Linker are written in TAO, which enables the user to rue the capability of TAO in microcodes. Since debugging tools are also written in a mini-Lisp, many new tools were developed in parallel to debugging of microcodes. This high level approach to firmware development environments is very important to provide high productivity of development.
Fault Tolerance in VLSI Circuits
Authors: Israel Koren, Adit D. Singh
Venue: Computer (1990)

The defects that can occur when manufacturing VLSI ICs and the faults that can result are described. Some commonly used restructuring techniques for avoiding defective components are discussed. Several defect-tolerant designs of memory ICs, logic ICs, and wafer-scale circuits are presented. Yield models for predicting the yield of chips with redundancy are introduced, and the optimal amount of redundancy is determined.
Interprocedual data flow testing
Authors: Mary Jean Harrold, Mary Lou Soffa
Venue: Proceedings of the ACM SIGSOFT '89 third symposium on Software testing, analysis, and verification (1989)

As current trends in programming encourage a high degree of modularity, the number of procedure calls and returns executed in a module continues to grow. This increase in procedures mandates the efficient testing of the interactions among procedures. In this paper, we extend the utility of data flow testing to include the testing of data dependencies that exist across procedure boundaries. An interprocedural data flow analysis algorithm is first presented that enables the efficient computation of information detailing the locations of definitions and uses needed by an interprocedural data flow tester. To utilize this information, a technique to guide the selection and execution of test cases, that takes into account the various associations of names with definitions and uses across procedures, is also presented. The resulting interprocedural data flow tester handles global variables, reference parameters and recursive procedure calls, and is compatible with the current intraprocedural data flow testing techniques. The testing tool has been implemented on a Sun 3/50 Workstation.
X-NET: a dual bus fiber-optic LAN using active switches
Authors: A. E. Kamal, B. W. Abeysundara
Venue: Symposium proceedings on Communications architectures protocols (1989)

X-Net is a new local area network based on the dual, unidirectional bus topology. Stations are connected to two fiber-optic busses using active switches. At light load, X-Net behaves as a random access scheme. With increasing load, transmissions are done in an orderly manner, arranged into cycles. The main advantage of X-Net is its superior channel utilization and delay performance, compared to other bus schemes. The packet delay is bounded at all loads. Performance is shown to be satisfactory over a wide range of a values, where a is the ratio of end-to-end medium propagation delay to the packet transmission time. Therefore, X-Net is a suitable candidate for operation at high speeds.
An architecture for network-layer routing in OSI
Authors: P. F. Tsuchiya
Venue: Proceedings of the ACM workshop on Frontiers in computer communications technology (1987)

Work on the standardization of routing protocols for OSI is in progress. The envisioned set of routing protocols is expected to work in nearly all of the environments which constitute OSI networks. Behind these routing protocols is an architecture which outlines problems and goals, establishes a framework upon which to base the development of protocols, and provides a conceptual baseline for continued work on unsolved problems. This architecture defines routing in the OSI network layer, functionally partitions the problem into its components, defines a routing hierarchy and an address hierarchy and discusses their relationship, and discusses arms-length routing relationships between differently administered networks. This paper presents that architecture, and discusses problems which remain to be solved as work progresses towards a global OSI network.
AIDE: an automated tool for teaching design in an introductory programming course
Authors: Dino Schweitzer, Scott C. Teel
Venue: Proceedings of the twentieth SIGCSE technical symposium on Computer science education (1989)

The Department of Computer Science at the United States Air Force Academy teaches an introductory Pascal programming and problem solving course to 1400 freshman a year. Although the students have a wide range of prior programming experiences, very few have any practice with program design. To encourage proper solution design and alleviate the burdensome and demotivating reams of design documentation, the Department of Computer Science has developed an automated tool, the Automated Interactive Design Editor (AIDE). This paper will provide some background on the problems associated with student design documentation, describe how AIDE attempts to address this problem, and discuss future directions for the tool.
First order compiler: A deterministic logic program synthesis algorithm
Authors: Taisuke Sato, Hisao Tamaki
Venue: Journal of Symbolic Computation (1989)

We present the first order compiler, a deterministic algorithm that can compile logic programs augmented with universally quantified implicational goals into definite clause programs. It is based on the deductive unfold/fold transformation applied to universal-continuation forms, realization of continuation concept in logic programming. The compiled program is assured to be partially correct wrt the source program.
A deductive database based on aristotelian logic
Authors: Eyal Mozes
Venue: Journal of Symbolic Computation (1989)

The paper proposes a new type of deductive database, whose structure is based on Aristotle's rules of the syllogism. This type of database demonstrates the advantages of Aristotelian logic over more modern formalisms for applications in which natural and informative interaction with human users is important. The structure and deductive procedures of the database are described and compared to other work in the area, and the unique capabilities of its user interaction are demonstrated by examples from a session with a prototype system.
A comparison of high-availability media recovery techniques
Authors: George Copeland
Venue: ACM SIGMOD Record (1989)

We compare two high-availability techniques for recovery from media failures in database systems. Both techniques achieve high availability by having two copies of all data and indexes, so that recovery is immediate. &ldquo;Mirrored declustering&rdquo; spreads two copies of each relation across two identical sets of disks. &ldquo;Interleaved declustering&rdquo; spreads two copies of each relation across one set of disks while keeping both copies of each tuple on separate disks. Both techniques pay the same costs of doubling storage requirements and requiring updates to be applied to both copies. Mirroring offers greater simplicity and universality. Recovery can be implemented at lower levels of the system software (e.g., the disk controller). For architectures that do not share disks globally, it allows global and local cluster indexes to be independent. Also, mirroring does not require data to be declustered (i.e., spread over multiple disks). Interleaved declustering offers significant improvements in recovery time, mean time to loss of both copies of some data, throughput during normal operation, and response time during recovery. For all architectures, interleaved declustering enables data to be spread over twice as many disks for improved load balancing. We show how tuning for interleaved declustering is simplified because it is dependent only on a few parameters that are usually well known for a specific workload and system configuration.
Adaptive Fault-Tolerant Routing in Hypercube Multicomputers
Authors: Ming-Syan Chen, Kang G. Shin
Venue: IEEE Transactions on Computers (1990)

A connected hypercube with faulty links and/or nodes is called an injured hypercube. A distributed adaptive fault-tolerant routing scheme is proposed for an injured hypercube in which each node is required to know only the condition of its own links. Despite its simplicity, this scheme is shown to be capable of routing messages successfully in an injured n-dimensional hypercube as long as the number of faulty components is less than n. Moreover, it is proved that this scheme routes messages via shortest paths with a rather high probability, and the expected length of a resulting path is very close so that of a shortest path. Since the assumption that the number of faulty components is less than n in an n-dimensional hypercube might limit the usefulness of the above scheme, a routing scheme based on depth-first search which works in the presence of an arbitrary number of faulty components is introduced. Due to the insufficient information on faulty components, however, the paths chosen by this scheme may not always be the shortest. To guarantee all messages to be routed via shortest paths, the authors propose to equip every node with more information than that on its own links. The effects of this additional information on routing efficiency are analyzed, and the additional information to be kept at each node for the shortest path routing is determined. Several examples and remarks are given to illustrate the results.
Mandatory security in object-oriented database systems
Authors: M. B. Thuraisingham
Venue: Conference proceedings on Object-oriented programming systems, languages and applications (1989)

A multilevel secure object-oriented data model (using the ORION data model) is proposed for which mandatory security issues in the context of a database system is discussed. In particular the following issues are dealt with: (1) the security policy for the system, (2) handling polyinstantiation, and (3) handling the inference problem. A set of security properties that has been established in this paper is more complete than those that have been proposed previously. Finally we describe how certain security constraints are handled by our model.
Half-Hot State Assignments for Finite State Machines
Authors: D. J. Rosenkrantz
Venue: IEEE Transactions on Computers (1990)

The state assignment problem for the programmable logic array (PLA) implementation of finite state machines is considered. It is pointed out that the number of PLA columns can be reduced by using state assignments leading to logic that is unate in the state variables. Half-hot state assignments are proposed, where each state has an encoding in which exactly half the state variables are equal to 1.
Sixth graders and shared data: designing a LAN environment to support collaborative work
Authors: Denis Newman
Venue: Proceedings of the 1988 ACM conference on Computer-supported cooperative work (1988)

A local area network system was developed to support collaborative science activities in sixth grade classrooms. Analyses of the students' understandings of the system showed they used the social organization of the classroom activities as a frame of reference. Their misconceptions are accounted for by the ways that the system did not properly reflect the activities in which the students were engaged.
An integrated environment for development and execution of real-time programs
Authors: B. Bruegge, T. Gross
Venue: Proceedings of the 2nd international conference on Supercomputing (1988)

The goal of the Warp Programming Environment (WPE) is to provide easy access to the Warp machine, a parallel supercomputer with a peak performance of 100 MFLOPS that is based on the systolic array architecture. The Warp Programming Environment offers a uniform environment for editing, compiling, debugging and executing Warp programs. It is based on an extensible shell written in Common Lisp and a runtime system written in C. It runs on a network of SUN-3 workstations under UNIX 4.2. This paper describes how the program development environment interacts with the Warp machine to support the development and execution of real-time programs on Warp.
A DBMS for large design automation databases
Authors: M. Haynie
Venue: Proceedings of the 1988 ACM SIGMOD international conference on Management of data (1988)

Large capacity Design Automation (CAD/CAM) database management systems require special capabilities over and above what commercial DBMSs or small workstation-based CAD/CAM systems provide. This paper describes one such system, Tacoma, used at Amdahl Corporation for the storage and retrieval of LSI and VLSI mainframe computer designs Tacoma is based on the relational model with additional object-oriented database features.