ppxscal/embedding_network huggingface dataset:
Efficient local search for very large-scale satisfiability problems
Authors: Jun Gu
Venue: ACM SIGART Bulletin (1992)

The satisfiability problem (SAT) is a fundamental problem in mathematical logic, inference, automated reasoning, and computing theory. In this correspondence, we report the results of applying local search techniques to solve the satisfiability problem. While a traditional resolution-based algorithm is not able to handle even moderately sized inference problems, a local search algorithm, tested through years of real program execution, is capable of computing very large-scale inference problems with fast, robust convergence. On a workstation computer, for example, it is able to solve a satisfiability problem with 50,000 clauses and 5,000 variables in a few seconds.
A method of acquiring formal specifications from examples
Authors: Lu Jian
Venue: ACM SIGSOFT Software Engineering Notes (1992)

The acquisition of the formal specification is very important in software development automation. This paper presents a method which combines the concept formation and the antecedent derivation mechanism to accomplish the automatic acquisition of the formal specification from the example specification and the plausibility of the generated formal specification is guaranteed in some sense.
Projecting Software Defects from Analyzing Ada Designs
Authors: William W. Agresti, William M. Evanco
Venue: IEEE Transactions on Software Engineering (1992)

Models for projecting software defects from analyses of Ada designs are described. The research is motivated by the need for technology to analyze designs for their likely effect on software quality. The models predict defect density based on product and process characteristics. Product characteristics are extracted from a static analysis of Ada subsystems, focusing on context coupling, visibility, and the import-export of declarations. Process characteristics provide for effects of reuse level and extent of changes. Multivariate regression analyses were conducted with empirical data from industry/government-developed projects: 16 Ada subsystems totaling 149000 source lines of code. The resulting models explain 63-74% of the variation in defect density of the subsystems. Context coupling emerged as a consistently significant variable in the models.
Resolutions via homological perturbation
Authors: Larry A. Lambe
Venue: Journal of Symbolic Computation (1991)

Perturbation theory is a useful way to obtain relatively small differential complexes representing a given chain homotopy type. An important part of the theory is ''the basic perturbation lemma'' which allows the transfer of structure between differential graded modules M and N of the same homotopy type when the differential in one has been changed. Under certain circumstances, the theory can be applied to obtain resolutions over algebras which are ''perturbations'' of algebras over which resolutions are known. For example, if D is any finitely generated torsion-free nilpotent group then the integral group ring A=Z(D) may be considered as a perturbation of the ring of Laurent polynomials. The theory may then be applied to a well-known resolution over the Laurent polynomials to obtain a resolution over the group ring. More general classes of algebras are discussed in ''Homological Perturbation theory, Hochschild homology and formal groups'' by the author (to appear). There is a trade-off between the size of the resolutions which arise from the perturbation method and the complexity of the new differential. In order to keep the modules relatively small, there is a considerable increase in the algebraic complexity of the resulting differentials. In order to study such complexes systematically, examples are needed, To facilitate such study, the Scratchpad system was used to set up and perform the necessary calculations. Because of the way Scratchpad is organized, this could be done in a way that minimizes programming effort and provides the natural mathematical environment for such calculations. In this paper, we discuss some of the general theory behind homological perturbation theory, give an idea of what is needed to make calculations within that theory in Scratchpad, and calculate a resolution of the integers over the integral group ring of the 4 x 4 upper triangular matrices with ones along the diagonal.
Evaluating text categorization
Authors: David D. Lewis
Venue: Proceedings of the workshop on Speech and Natural Language (1991)

While certain standard procedures are widely used for evaluating text retrieval systems and algorithms, the same is not true for text categorization. Omission of important data from reports is common and methods of measuring effectiveness vary widely. This has made judging the relative merits of techniques for text categorization difficult and has disguised important research issues.In this paper I discuss a variety of ways of evaluating the effectiveness of text categorization systems, drawing both on reported categorization experiments and on methods used in evaluating query-driven retrieval. I also consider the extent to which the same evaluation methods may be used with systems for text extraction, a more complex task. In evaluating either kind of system, the purpose for which the output is to be used is crucial in choosing appropriate evaluation methods.
An Improved Vector-Reduction Method
Authors: Henk J. Sips, Haixiang Lin
Venue: IEEE Transactions on Computers (1991)

A pipelined vector-reduction method that is based on L.M. Ni and K. Hwang's (1985) symmetric and asymmetric reduction methods is discussed. It is shown that the proposed method is the fastest among known pipelined vector-reduction methods.
Advanced capabilities of the outer join
Authors: Michael M. David
Venue: ACM SIGMOD Record (1992)

This paper demonstrates that the modeling of complex data structures can be performed easily and naturally in SQL using the direct outer join operation as defined in the proposed ISO-ANSI SQL2 standard. This paper goes on to demonstrate four advanced capabilities that can be implemented by SQL vendors utilizing the data modeling ability of the outer join. These capabilities are: powerful optimization techniques that can dynamically shorten the access path length; intelligent join view updates that utilize the semantics in the data structure being modeled; direct disparate heterogeneous database access that is transparent and efficient; and automatic conversion of multi-table structures into nested relations allowing for more powerful SQL operations.
Pseudorandom Bit Generators in Stream-Cipher Cryptography
Authors: Kencheng Zeng, Chung-Huang Yang, Dah-Yea Wei, T. R. N. Rao
Venue: Computer (1991)

Progress in the design and analysis of pseudorandom bit generators over the last decade is surveyed. Background information is provided, and the linear feedback shift registers that serve as building blocks for constructing the generators are examined. Three methods for attacking keystream generators are reviewed, and three techniques for designing them are considered, focusing on how they fail or how their weakness is exposed under the attacks previously described. These techniques are nonlinear feedforward transformation, step control, and multiclocking.
Direct Recovery of Motion and Shape in the General Case by Fixation
Authors: M. Ali Taalebinezhaad
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1992)

A direct method called fixation is introduced for solving the general motion vision problem: arbitrary motion relative to an arbitrary environment. This method results in a linear constraint equation that explicitly expresses the rotational velocity in terms of the translational velocity. The combination of this constraint equation with the brightness-change constraint equation solves the general motion vision problem. Avoiding correspondence and optical flow has been the motivation behind this direct method, which uses the image brightness information such as temporal and spatial brightness gradients directly. In contrast with previous direct methods, the fixation method does not put any severe restrictions on the motion or the environment. Moreover, the fixation method neither requires tracked images as its input nor uses tracking for obtaining fixated images. Instead, it introduces a pixel shifting process to construct fixated images for any arbitrary fixation point. This is done entirely in software without any use of camera motion for tracking.
Using public domain multiprecision arithmetic packages for computer security software applications on a personal computer
Authors: Selwyn Russell
Venue: ACM SIGSMALL/PC Notes (1992)

Implementation of modern cryptography needs both normal and modular arithmetic using numbers with hundreds of digits. This is often a discouragement to the use of such methods, even though a number of public domain packages are available. This paper shows how available multiprecision packages can easily be used to incorporate arbitrarily high security into computer systems. Examples using the readily available Lenstra package for the RSA and El Gamal cryptosystems are given.
Manpower profiling for information technology: a case study
Authors: H. M. Hosny, M. S. Akabawy, T. G. Gough
Venue: ACM SIGCSE Bulletin (1992)

Information Technology (IT) is finding its way rather too quickly into the job markets in the developing countries. There is a growing demand for IT trained staff but no specific dimensions have been provided for the types of graduates needed in the local marketplace.A survey has been carried out of a wide cross section of IT employers in Egypt, as a typical example of a developing country with great potential for technological advancement. The objective of the survey was to identify the employers' present employment patterns as well as their needs for trained personnel in the IT field, at present and in the near future.
Experience with a stack decoder-based HMM CSR and back-OFF N-gram language models
Authors: Douglas B. Paul
Venue: Proceedings of the workshop on Speech and Natural Language (1991)

Stochastic language models are more useful than non-stochastic models because they contribute more information than a simple acceptance or rejection of a word sequence. Back-off N-gram language models [11] are an effective class of word based stochastic language model. The first part of this paper describes our experiences using the back-off language models in our time-synchronous decoder CSR. A bigram back-off language model was chosen for the language model to be used in the informal ATIS CSR baseline evaluation test[13, 21].The stack decoder[2, 8, 24] is a promising control structure for a speech understanding system because it can combine constraints from both the acoustic model and a long span language model (such as a natural language processor (NLP)) into a single integrated search[17]. A copy of the Lincoln time-synchronous HMM CSR has been converted to a stack decoder controlled search with stochastic language models. The second part of this paper describes our experiences with our prototype stack decoder CSR using no grammar, the word-pair grammar, and N-gram back-off language models.
Chain Reactions in Networks
Authors: Udi Manber
Venue: Computer (1990)

A set of situations that are susceptible to network disasters is identified. Several examples of actual breakdowns are presented. Although they occurred in different types of networks, they have grant similarities. Several examples of potential breakdowns that can result from very subtle design failures are also given. The discussion supports the belief that distributed programs in general can have very subtle design failures that are hard to detect. However, it is shown that although it is theoretically impossible to prevent the berserk loops of messages that can bring down an entire computer network, a carefully applied set of rules will minimize these disasters.
Parallel Processing of Large Node B-Trees
Authors: Miloš D. Ercegovac, Thomas Lang
Venue: IEEE Transactions on Computers (1990)

The performance improvement afforded by parallel processing of large-node B-trees is investigated. A node partitioning scheme to enhance concurrency for B-trees is presented. In the method, the tree height is reduced by increasing the node size. However, it is shown that increasing node size alone in conventional B-trees on parallel disks may not improve the response time, and may even degrade the performance. The proposed method achieves better performance while avoiding this anomaly.
Microcomputer training users?: do trained users differ from non-trained
Authors: Joey F. George, James W. Theis
Venue: ACM SIGMIS Database (1991)

The literature on computing in organizations assumes that users must be trained to get the most out of using their machines. The natural implication of this assumption is that trained users would differ markedly from non-trained users. Yet in exploratory survey research conducted in a large Southern California company, trained and non-trained microcomputer users did not differ along most work-related dimensions. Instead, where trained and non-trained users varied at all in their work habits and in their attitudes toward micros and training, the variation seemed more related to their desire for training, rather than to the training itself. The authors discuss the findings from this study and propose future research in the area of corporate-provided microcomputer training.
Software metrics: a re-evaluation and new applications
Authors: Austin Mellon
Venue: Proceedings of the 1992 ACM annual conference on Communications (1992)

Software metrics' research has produced as many failures as successes. Theoretical results supported by application experiences help us understand many of the pitfalls. We will discuss how some of these pitfalls can be avoided and how metrics' research can be made more robust so that we can improve the measurements.
A concise presentation of ITL
Authors: Nicola Guarino
Venue: ACM SIGART Bulletin (1991)

ITL (Intensional Terminological Language) is a Prolog-based language derived from our previous work on DRL. Like LOGIN, it improves the expressive adequacy of Prolog by the introduction of a separate theory, which represents the sortal structure of the domain. This theory is linked to the object theory by a simple form of order-sorted unification. Differently from LOGIN, however, ITL sorts are not complex structures similar to KLONE concepts. The reason is that ITL is not based on generic descriptions: roles (we call them attributes) are represented as independent concepts, which contribute to the structure of more complex concepts through separate statements expressing necessary conditions, sufficient conditions or structural constraints. The result is a fine-grained terminological language, whose syntax resembles in some way OMEGA. Yet, differently from OMEGA, this language does not have the full power of first order logic. It has however an intensional semantics, which we consider as an important characteristic of terminological knowledge. In this paper we briefly discuss the rationale behind ITL, and present its major characteristics.
Substring parsing for arbitrary context-free grammars
Authors: Jan Rekers, Wilco Koorn
Venue: ACM SIGPLAN Notices (1991)

A substring recognizer for a language L determines whether a string s is a substring of a sentence in L, i.e., substring-recognize(s) succeeds if and only if exist;v, w: vsw isin; L. The algorithm for substring recognition presented here accepts general context-free grammars and uses the same parse tables as the general context-free parsing algorithm from which it was derived. Substring recognition can be useful for noncorrecting syntax error recovery and for incremental parsing. By extending the substring recognizer with the ability to generate trees for the possible contextual completions of the substring, we obtain a substring parser, which can be used in a syntax-directed editor to complete fragments of sentences.
Pray Mr. Babbage-A character study in dramatic form
Authors: Maurice V. Wilkes
Venue: IEEE Annals of the History of Computing (1991)

Babbage is noted for his technical, belatedly recognized, triumphs of computational technology; his personality has been the subject of scrutiny by several authors. Towards his end of life he is said to have wished that he could exchange the remainder of his life for three days in the future. This play provides us with the opportunity to step back to his day and to see the man separate (as far as he would allow) from his machines. That we could grant his wish...
Parallelization of a radiation transport simulation code on the BBN TC2000 parallel computer
Authors: William Celmaster, Edward N. May
Venue: Proceedings of the 1990 ACM/IEEE conference on Supercomputing (1990)

We describe the parallelization of a radiation transport Monte Carlo simulation code that was used in the design of a particle detector.
On rigorous Transaction Scheduling
Authors: Yuri Breitbart, Dimitrios Georgakopoulos, Marek Rusinkiewicz, Abraham Silberschatz
Venue: IEEE Transactions on Software Engineering (1991)

The class of transaction scheduling mechanisms in which the transaction serialization order can be determined by controlling their commitment order, is defined. This class of transaction management mechanisms is important, because it simplifies transaction management in a multidatabase system environment. The notion of analogous execution and serialization orders of transactions is defined and the concept of strongly recoverable and rigorous execution schedules is introduced. It is then proven that rigorous schedulers always produce analogous execution and serialization orders. It is shown that the systems using the rigorous scheduling can be naturally incorporated in hierarchical transaction management mechanisms. It is proven that several previously proposed multidatabase transaction management mechanisms guarantee global serializability only if all participating databases systems produce rigorous schedules.
Translation&mdash;an introductory exercise
Authors: Jerzy A. Piotrowski
Venue: ACM SIGCSE Bulletin (1992)

The paper presents a case for using the functional language Miranda dagger; as a tool in building simple models used in undergraduate Computer Science and Computer Engineering classes. Lexical analysis, parsing and generation of code are described by functions. However, only parsing is presented here with some detail, while two other phases are outlined. Some laboratory experiments suggested for students are also included.
Report on the CHI'90 workshop on structure editors
Authors: Lisa Neal, Gerd Szwillus
Venue: ACM SIGCHI Bulletin (1990)

Although work on structure editors has been going on for almost twenty years, the designers and users of syntax-directed editors and graphical structure editors had never met to reflect on these tools' past, present, and future. The CHI'90 Workshop on Structure Editors was organized for the purpose of examining structure editors from a human-computer interaction perspective. We also hoped to increase the intersection between the programming environment and human-computer interaction communities.
The ProcessWall: a process state server approach to process programming
Authors: Dennis Heimbigner
Venue: ACM SIGSOFT Software Engineering Notes (1992)

The ProcessWall is a process state server providing storage for process states plus operations for defining and manipulating the structure of those states. It separates the state of a software process from any program for constructing that state. Instead, client programs implement the processes for operating on the process state. This approach has a number of potential benefits such as support for process formalism interoperability, support for multiple process languages, low-cost retro-fitting of process into existing environments, and support for long-term execution of processes. The process server interface provides descriptive mechanisms for representing process state as well as product state. A classification of client programs is provided to show how the state server can be used in a variety of ways.
Genetic heuristics in optimization problems (abstract)
Authors: Sami Khuri, My Hoang
Venue: Proceedings of the 1990 ACM annual conference on Cooperation (1990)

In this work we investigate different heuristics for solving NP-hard problems. These heuristics explore the solution space in a parallel fashion, attempting to converge to an optimal solution by mimicking the way natural selection and genetics favor the fittest candidates. These randomized, but not directionless, search procedures were developed and labeled genetic algorithms by John Holland. We apply the heuristics to various classical optimization problems, including the knapsack problem and the maximum cut problem. The latter consists of partitioning the set V of vertices of a graph G = (V, E) into two disjoint sets V1 and V2 such that the sum of the weights of the edges from E that have one endpoint in V1 and the other in V2, is maximized. Starting with a randomly chosen initial population, the genetic algorithm will move from one generation to a better one by using the operations of reproduction, crossover and mutation. We investigate and compare different crossover techniques. The survival of well fit individuals is based on the computation of a fitness function which is closely related to the objective function in the optimization problem. This study considers and compares various fitness functions. We thus make use of a fitness function that penalizes overfilled knapsacks for instance. We conclude this work by giving a few suggestions on the use of genetic algorithms in combinatorial optimization problems.
Logic optimization algorithm by linear programming approach
Authors: Naohiro Kageyama, Chihei Miura, Tsuguo Shimizu
Venue: Proceedings of the 27th ACM/IEEE Design Automation Conference (1991)

A new algorithm for reducing the delay time with the least increase of gate is presented. This algorithm uses a linear programming approach and makes it possible for delay and gate optimization to be achieved simultaneously from the global point of view. Therefore, this new algorithm prevents the generation of redundant logic arising from the delay time improvement, which is a weakness of the conventional method.
Four State Asynchronous Architectures
Authors: Anthony J. McAuley
Venue: IEEE Transactions on Computers (1992)

An approach is presented to high-performance asynchronous architectures offering significant advantages over conventional clocked systems, without some of the drawbacks normally associated with asynchronous techniques. As the level of integration increases, an asynchronous wavefront array designed using the techniques described will have three important advantages over the equivalent synchronous systolic array: faster throughput (rate at which data are clocked through a system), reduced design complexity, and greater reliability. The benefits and drawbacks of using the asynchronous technique are highlighted using three wavefront arrays: two one-dimensional multipliers, and a two-dimensional sorter. All three can be built using just one basic building block.