ppxscal/embedding_network huggingface dataset:
The concurrency control problem in multidatabases: characteristics and solutions
Authors: Sharad Mehrotra, Rajeev Rastogi, Yuri Breitbart, Henry F. Korth, Avi Silberschatz
Venue: Proceedings of the 1992 ACM SIGMOD international conference on Management of data (1992)

A Multidatabase System (MDBS) is a collection of local database management systems, each of which may follow a different concurrency control protocol. This heterogeneity makes the task of ensuring global serializability in an MDBS environment difficult. In this paper, we reduce the problem of ensuring global serializability to the problem of ensuring serializability in a centralized database system. We identify characteristics of the concurrency control problem in an MDBS environment, and additional requirements on concurrency control schemes for ensuring global serializability. We then develop a range of concurrency control schemes that ensure global serializability in an MDBS environment, and at the same time meet the requirements. Finally, we study the tradeoffs between the complexities of the various schemes and the degree of concurrency provided by each of them.
A triangulation algorithm from arbitrary shaped multiple planar contours
Authors: A. B. Ekoule, F. C. Peyrin, C. L. Odet
Venue: ACM Transactions on Graphics (TOG) (1991)

Conventional triangulation algorithms from planar contours suffer from some limitations. For instance, incorrect results can be obtained when the contours are not convex, or when the contours in two successive slices are very different. In the same way, the presence of multiple contours in a slice leads to ambiguities in defining the appropriate links. The purpose of this paper is to define a general triangulation procedure that provides a solution to these problems. We first describe a simple heuristic triangulation algorithm which is extended to nonconvex contours. It uses an original decomposition of an arbitrary contour into elementary convex subcontours. Then the problem of linking one contour in a slice to several contours in an adjacent slice is examined. To this end, a new and unique interpolated contour is generated between the two slices, and the link is created using the previously defined procedure. Next, a solution to the general case of linking multiple contours in each slice is proposed. Finally, the algorithm is applied to the reconstitution of the external surface of a complex shaped object: a human vertebra.
Image Understanding Architecture: Exploiting Potential Parallelism in Machine Vision
Authors: Charles C. Weems, Edward M. Riseman, Allen R. Hanson
Venue: Computer (1992)

A hardware architecture that addresses at least part of the potential parallelism in each of the three levels of vision abstraction, low (sensory), intermediate (symbolic), and high (knowledge-based), is described. The machine, called the image understanding architecture (IUA), consists of three different, tightly coupled parallel processors; the content addressable array parallel processor (CAAPP) at the low level, the intermediate communication associative processor (ICAP) at the intermediate level, and the symbolic processing array (SPA) at the high level. The CAAPP and ICAP levels are controlled by an array control unit (ACU) that takes its directions from the SPA level. The SPA is a multiple-instruction multiple-data (MIMD) parallel processor, while the intermediate and low levels operat in multiple modes. The CAAPP operates in single-instruction multiple-data (SIMD) associative or multiassociative mode, and the ICAP operates in single-program multiple-data (SPMD) or MIMD mode.
A software authentication system for the prevention of computer viruses
Authors: Lein Harn, Hung-Yu Lin, Shoubao Yang
Venue: Proceedings of the 1992 ACM annual conference on Communications (1992)

In the absence of systematic techniques to detect the existence of computer viruses, preventing suspicious software from entering the system at the initial point of entry appears to be the best method to protect computing resources against attacks of computer viruses. Currently, software is distributed primarily by diskettes instead of online transmission. Diskettes are more susceptible to modification and masquerading while on-line transmission usually follows proper user/message authentication. A software authentication system is proposed which does not require a mutually trusted center of both software vendors and users, or users' interaction with any key center. Vendors assume responsibility by signing released software and users verify the authenticity of received software before using it. Through such an authentication process, users eliminate the risk of running &ldquo;unlicensed&rdquo; or modified programs, thus eliminating the possibility of virus infections.
IS personnel: do they form an occupational community?
Authors: Katherine A. Duliba, Jack Baroudi
Venue: ACM SIGCPR Computer Personnel (1991)

The purpose of this paper is to determine the extent to which information system (IS) personnel form an occupational community. To this end, a model of an occupational community is developed. Occupational communities are hypothesized to form when people are highly involved in and identify with their work, when the work itself is inclusive, and when people are isolated (in terms of geography and/or time.) Data was obtained on the strength of the IS occupational community, and on the three antecedents of involvement, inclusivity, and isolation, through semi-structured interviews with IS personnel. The results show that IS personnel form a weak occupational community, if they can be said to form an occupational community at all.
Test Scheduling in High Performance VLSI System Implementations
Authors: John Y. Sayah, Charles R. Kime
Venue: IEEE Transactions on Computers (1992)

The authors provide tools for exploring the inherent parallelism introduced by design for testability (DFT) and built-in self-test (BIST) techniques in order to reduce test length. Since the potential for parallel test execution is most apparent at the organization level and DFT and BIST hardware is also often added at that level, the organization level is used as a foundation for the work. A broader modeling foundation that encompasses both dimensions, space and time, of test parallelism is introduced. A set of simple schedulability criteria for concurrent issuing of tests is developed. Effective suboptimum heuristic-based algorithms for scheduling tests on general-purpose high-performance VLSI system implementation are presented. The scheduling algorithms have been implemented and performance results are presented.
Another stemmer
Authors: Chris D. Paice
Venue: ACM SIGIR Forum (1990)

In natural language processing, conflation is the process of merging or lumping together nonidentical words which refer to the same principal concept. This can relate both to words which are entirely different in form (e.g., "group" and "collection"), and to words which share some common root (e.g., "group", "grouping", "subgroups"). In the former case the words can only be mapped by referring to a dictionary or thesaurus, but in the latter case use can be made of the orthographic similarities between the forms. One popular approach is to remove affixes from the input words, thus reducing them to a stem; if this could be done correctly, all the variant forms of a word would be converted to the same standard form. Since the process is aimed at mapping for retrieval purposes, the stem need not be a linguistically correct lemma or root (see also Frakes 1982).
Adaptive Smoothing: A General Tool for Early Vision
Authors: Philippe Saint-Marc, Jer-Sen Chen, Gérard Medioni
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1991)

A method to smooth a signal while preserving discontinuities is presented. This is achieved by repeatedly convolving the signal with a very small averaging mask weighted by a measure of the signal continuity at each point. Edge detection can be performed after a few iterations, and features extracted from the smoothed signal are correctly localized (hence, no tracking is needed). This last property allows the derivation of a scale-space representation of a signal using the adaptive smoothing parameter k as the scale dimension. The relation of this process to anisotropic diffusion is shown. A scheme to preserve higher-order discontinuities and results on range images is proposed. Different implementations of adaptive smoothing are presented, first on a serial machine, for which a multigrid algorithm is proposed to speed up the smoothing effect, then on a single instruction multiple data (SIMD) parallel machine such as the Connection Machine. Various applications of adaptive smoothing such as edge detection, range image feature extraction, corner detection, and stereo matching are discussed.
Every computer programme is actually a simulation model (abstract)
Authors: G. Arthur Mihram, Danielle Mihram
Venue: Proceedings of the 1990 ACM annual conference on Cooperation (1990)

We linguistically compare computer programming with mathematics, revealing that the algorithmic (second-person) nature of the first makes it distinctly different from the third-person character of mathematics. But, in reviewing the literature [e.g., HAWAII INT'L CONFER SYSTEM SCIENCES, 1985: 3060316; NOTICES, Amer Math Soc 24: A-313 and 25: A-463, 1978], we show that this algorithmic nature implies that every computer program is a mimic of a decider, or decision-making process, and therefore a simulation model (of something, of some process). The conclusion becomes of pertinence in view of the established isomorphism [cf. SIMULATION: STATISTICAL FOUNDATIONS AND METHODOLOGY, 1972 (1970)] between the six-stage model-building process of simulation methodology and the Scientific Method, as the latter has been conducted historically. Thus, the credibility of computer programs becomes the age-old question of the truth of any other scientific writing/report, since Science is that human activity devoted to the very explanation for (i.e., to seeking the truth about) a naturally occurring phenomenon. As importantly, this six-stage model-building process which we humans conduct extra-corporeally is one-to-one isomorphic to the six-stage chemical model-building process which has ensured biological survival [cf. AN EPISTLE TO DR. BENJAMIN FRANKLIN, 1975 (1974)]: first &ldquo;used&rdquo; by plants and animals in chemico-genetic models for survival and then &ldquo;employed&rdquo; (non-consciously, of course) by the &ldquo;higher&rdquo; animals via chemico-neural modelling to enhance day-to-day survival. We provide several examples to reveal the distinction between computer programming and mathematics, then move to the titular theme, using as examples the presently widespread bibliographical retrieval software: actually, simulation models of the reference librarian (or researcher) at work.
Training, ability, and the acceptance of information technology: an empirical study of IS personnel and end users
Authors: R. Ryan Nelson, Michael W. Kattan, Paul H. Cheney
Venue: ACM SIGCPR Computer Personnel (1991)

This article validates a conceptual model of the relationship among training, ability, and acceptance of information technology within organizations. Previously developed to explain the relationship for end users, the model is tested for information systems personnel as well. To examine these variables (training, ability, and acceptance) and their interrelationships, an instrument was developed, pretested, and completed by 232 employees at eight different organizations. Based on the results of this study, the model is validated for both IS personnel and end users of information technology, indicating that positive relationships exist between (1) the IT-related training of an individual and his/her ability to use IT, (2) an individual's ability to use IT and his/her use of IT, and (3) an individual's ability to use IT and his/her satisfaction with IT. The implications and possibilities for further research are discussed.
A novel single instruction computer architecture
Authors: P. A. Laplante
Venue: ACM SIGARCH Computer Architecture News (1990)

A single processing computer system using only half-adder circuits is described. In addition, it is shown that only a single hard-wired instruction is needed in the control unit to obtain a complete [1] instruction set for this general purpose computer. Such a system has several advantages. First it is intrinsically a RISC machine-in fact the "ultimate RISC" machine. Second, because only a single type of logic element is employed the entire computer system can be easily realized on a single, highly integrated chip. Finally, due to the homogeneous nature of the computer's logic elements, the computer has possible implementations as an optical or chemical machine. This in turn suggests possible paradigms for neural computing and artificial intelligence. This approach was inspired by a paper by van der Poel [5] in which a single instruction is used to furnish a complete set [1] of general purpose instructions.
Graphical user interfaces for the management of scientific experiments and data
Authors: Yannis E. Ioannidis, Miron Livny, Eben M. Haber
Venue: ACM SIGMOD Record (1992)

It is often stated that the three most important factors that determine the success or failure of a database system are performance, performance, performance! The experience of the last twenty years with relational systems has shown that at least one of these three references to performance implies that of end-users when interacting with the system to access data, i.e., user productivity. Although declarative query languages like SQL and QUEL represent major improvements over procedural programming languages like COBOL, the overall consensus is that they are too complex for many users. The need for more intuitive and easier to learn and use interfaces to database systems is always current.
An optimal algorithm for floorplan area optimization
Authors: Ting-chi Wang, D. F. Wong
Venue: Proceedings of the 27th ACM/IEEE Design Automation Conference (1991)

In this paper we present an optimal algorithm for the floorplan area optimization problem. Our algorithm is based on an extension of the technique in [5]. Experimental results indicate that our algorithm is efficient and capable of successfully handling large floorplans. We compare our algorithm with the branch-and-bound optimal algorithm in [6]. The running time of our algorithm is substantially less than that of [6]. For several examples where the algorithm in [6] ran for days and did not terminate, our algorithm produced optimal solutions in a few seconds.
Speaker independent phonetic transcription of fluent speech for large vocabulary speech recognition
Authors: S. E. Levinson, M. Y. Liberman, A. Ljolje, L. G. Miller
Venue: Proceedings of the workshop on Speech and Natural Language (1989)

Speaker independent phonetic transcription of fluent speech is performed using an ergodic continuously variable duration hidden Markov model (CVDHMM) to represent the acoustic, phonetic and phonotactic structure of speech. An important property of the model is that each of its fifty-one states is uniquely identified with a single phonetic unit. Thus, for any spoken utterance, a phonetic transcription is obtained from a dynamic programming (DP) procedure for finding the state sequence of maximum likelihood. A model has been constructed based on 4020 sentences from the TIMIT database. When tested on 180 different sentences from this database, phonetic accuracy was observed to be 56% with 9% insertions. A speaker dependent version of the model was also constructed. The transcription algorithm was then combined with lexical access and parsing routines to form a complete recognition system. When tested on sentences from the DARPA resource management task spoken over the local switched telephone network, phonetic accuracy of 64% with 8% insertions and word accuracy of 87% with 3% insertions was measured. This system is presently operating in an on-line mode over the local switched telephone network in less than ten times real time on an Alliant FX-80.
Object behaviors and scripts: (extended abstract)
Authors: Guozhu Dong, Jianwen Su
Venue: Proceedings of the third international workshop on Database programming languages : bulk types persistent data: bulk types persistent data (1992)

An object-oriented database (OODB) schema consists of class hierarchies, attributes, and methods. Two method languages are considered: one has operators to create, delete, modify, and migrate objects; the other is extended with temporal conditions. A script is a graph with edges labelled by methods. An object state includes the set of classes it belongs to and values of attributes. The object behavior is a sequence of object states the object goes through during its lifetime. Object behaviors under OODB schemas with sripts are studied. A tool, domain automaton, is introduced, extending a finite state automaton to an infinite alphabet. The equivalence of two domain automata is shown to be decidable. For the simple (extended) language, behaviors under each OODB schema with scripts correspond to the language of a (two-way) domain automaton. Testing whether two OODB schemas with scripts generate the same behaviors is decidable for the simple language; still open for the extended language.
Better bounds for threshold formulas
Authors: Jaikumar Radhakrishnan
Venue: Proceedings of the 32nd annual symposium on Foundations of computer science (1991)

The computation of threshold functions using formulas over the basis (AND, OR, NOT) is considered. It is shown that every monotone formula that computes the threshold function T/sub k//sup n/2
Context-Based Vision: Recognizing Objects Using Information from Both 2D and 3D Imagery
Authors: Thomas M. Strat, Martin A. Fischler
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1991)

Results from an ongoing project concerned with recognizing objects in complex scene domains, especially in the domain that includes the natural outdoor world, are described. Traditional machine recognition paradigms assume either that all objects of interest are definable by a relatively small number of explicit shape models or that all objects of interest have characteristic, locally measurable features. The failure of both assumptions has a dramatic impact on the form of an acceptable architecture for an object recognition system. In this work, the use of the contextual information is a central issue, and a system is explicitly designed to identify and use context as an integral part of recognition that eliminates the traditional dependence on stored geometric models and universal image partitioning algorithms. This paradigm combines the results of many simple procedures that analyze monochrome, color, stereo, or 3D range images. Interpreting the results along with relevant contextual knowledge makes it possible to achieve a reliable recognition result, even when using imperfect visual procedures. Initial experimentation with the system on ground-level outdoor imagery has demonstrated competence beyond what is attainable with other vision systems.
A simple stochastic model for computer terminal availability
Authors: Scott P. Stevens, Robert G. Brookshire
Venue: ACM SIGUCCS Newsletter (1992)

Queueing models have been widely applied in the analysis of computer performance, as well as in the study of systems in which service is rendered to human customers by multiple servers. Rarely, however, have queueing theory techniques been applied to the problem of providing computing services to the human beings who require them.We develop a simple queueing model for the availability of computer terminals in an academic computing laboratory, then compare the statistics predicted by the model to those actually observed in several laboratories. Among the statistics considered is the likelihood that a new arrival to the laboratory finds no free terminals, a quantity which is comparable to standard performance measures for communications equipment. The model also generates measures of resource availability which may be analyzed dynamically. Examples of the use of this model are provided.
Stochastic Modeling and Analysis of Propagation Delays in GaAs Adders
Authors: Branislava Pernuičic, Veljko Milutinovic
Venue: IEEE Transactions on Computers (1991)

The problem of how to assess the probability distribution function (PDF) of the propagation delay for different adder types in order to compare their sensitivities to stochastic changes of gate delays is addressed. An original methodology that solves the problem for combinational circuits of arbitrary topology (without loops) is introduced. Its capabilities are demonstrated through the modeling and analysis of propagation delays in GaAs adders. This methodology is directly applicable to a number of analogous problems in other fields.
The form of reusable Ada components for concurrent use
Authors: J. Carter
Venue: ACM SIGAda Ada Letters (1990)

Abstract data types are often chosen to implement reusable Ada components for sequential use. Those who have attempted to expand from sequential to concurrent considerations have frequently continued to use abstract data types for their implementation. This approach is shown to violate software engineering principles. The use of abstract state machines for concurrent components is shown to resolve these problems.
The use of relative duration in syntactic disambiguation
Authors: M. Ostendorf, P. J. Price, J. Bear, C. W. Wightman
Venue: Proceedings of the workshop on Speech and Natural Language (1990)

We describe the modification of a grammar to take advantage of prosodic information automatically extracted from speech. The work includes (1) the development of an integer "break index" representation of prosodic phrase boundary information, (2) the automatic detection of prosodic phrase breaks using a hidden Markov model on relative duration of phonetic segments, and (3) the integration of the prosodic phrase break information in SRI's Spoken Language System to rule out alternative parses in otherwise syntactically ambiguous sentences. Initial experiments using ambiguous sentences read by radio announcers achieved good results in both detection and parsing. Automatically detected phrase break indices had a correlation greater than 0.86 with hand-labeled data for speaker-dependent models; and, in a subset of sentences with preposition ambiguities, the number of parses was reduced by 25% with a simple grammar modification.
A portable and reusable RDBMS interface for Ada
Authors: Arnold M. Voketaitis,  Jr.
Venue: ACM SIGAda Ada Letters (1992)

Most software systems must support the maintenance of structured data using non-volatile storage media, and therefore require an interface to a relational database management system (RDBMS). This interface should ideally enable the movement of data into and out from a generic form of storage media by servicing requests which assume nothing relative to the underlying data management facility or data store. This paper will address the issues regarding the type of interface which best satisfies this need and will describe a proposed solution along with its applications.