ppxscal/embedding_network huggingface dataset:
A Datalog interface for SQL (abstract)
Authors: Kemal Koymen
Venue: Proceedings of the 1990 ACM annual conference on Cooperation (1990)

The research reported here describes a prototype datalog interface for SQL. Datalog is a logic based declarative language, a version of Prolog, suitable for database systems. The Datalog considered here does not support function symbols in logical rules. The prototype interface is an attempt to provide additional computational power to SQL via a declarative language. In this regard, it could be considered as the basis for a Knowledge Base Management System. The design of the interface involves three major components: Datalog Compiler, IC (Intermediate Code) Interpreter, and a CLI (Command Line Interpreter). The datalog compiler translates a given datalog program into an equivalent intermediate representation referred to as IC. The IC generated is suitable for efficient bottom-up evaluation of logical rules. In addition to IC generation, the compiler also performs several tasks such as safety checking and rectification of rules. The IC interpreter achieves the evaluation of the intermediate code, for logical rules, i.e.. the datalog program, in two stages. The first stage generates SQL statements whose execution would carry out the task as defined by the logical rules. The second phase executes the generated SQL statements by invoking the facilities provided by Pro*C interface to SQL. The SQL statement generation and execution processes are not done sequentially but interleaved. The last component, CLI, provides the user with facilities to invoke the functions of the datalog interface. The interface provides several functions, in addition to the two main ones: compile and execute.
Complexity Results on Learning by Neural Nets
Authors: Jyh-Han Lin, Jeffrey Scott Vitter
Venue: Machine Learning (1991)

We consider the computational complexity of learning by neural nets. We are interested in how hard it is to design appropriate neural net architectures and to train neural nets for general and specialized learning tasks. Our main result shows that the training problem for 2-cascade neural nets (which have only two non-input nodes, one of which is hidden) is {\mathscr NP}-complete, which implies that finding an optimal net (in terms of the number of non-input units) that is consistent with a set of examples is also {\mathscr NP}-complete. This result also demonstrates a surprising gap between the computational complexities of one-node (perceptron) and two-node neural net training problems, since the perceptron training problem can be solved in polynomial time by linear programming techniques. We conjecture that training a k-cascade neural net, which is a classical threshold network training problem, is also {\mathscr NP}-complete, for each fixed k &ge; 2. We also show that the problem of finding an optimal perceptron (in terms of the number of non-zero weights) consistent with a set of training examples is {\mathscr NP}-hard.Our neural net learning model encapsulates the idea of modular neural nets, which is a popular approach to overcoming the scaling problem in training neural nets. We investigate how much easier the training problem becomes if the class of concepts to be learned is known a priori and the net architecture is allowed to be sufficiently non-optimal. Finally, we classify several neural net optimization problems within the polynomial-time hierarchy.
From sequential layers to distributed processes: deriving a distributed minimum weight spanning tree algorithm
Authors: Wil Janssen, Job Zwiers
Venue: Proceedings of the eleventh annual ACM symposium on Principles of distributed computing (1992)

Analysis and design of distributed algorithms and protocols are difficult issues. An important cause for those difficulties is the fact that the logical structure of the solution is often invisible in the actual implementation. We introduce a framework that allows for a formal treatment of the design process, from an abstract initial design to an implementation tailored to specific architectures. A combination of algebraic and axiomatic techniques is used to verify correctness of the derivation steps. This is shown by deriving an implementation of a distributed minimum weight spanning tree algorithm in the style of [GHS].
Analysis and design of latch-controlled synchronous digital circuits
Authors: Karem A. Sakallah, Trevor N. Mudge, Oyekunle A. Olukotun
Venue: Proceedings of the 27th ACM/IEEE Design Automation Conference (1991)

We present a succinct formulation of the timing constraints for latch-controlled synchronous digital circuits. We show that the constraints are mildly nonlinear, and prove the equivalence of the nonlinear optimal cycle time calculation problem to an associated and simpler linear programming (LP) problem. We present an LP-based algorithm which is guaranteed to obtain the optimal cycle time for arbitrary circuits controlled by a general class of multi-phase overlapped clocks. We illustrate the formulation and an initial implementation of the algorithm on some example circuits.
A distributed object-oriented database system supporting shared and private databases
Authors: Won Kim, Nat Ballou, Jorge F. Garza, Darrell Woelk
Venue: ACM Transactions on Information Systems (TOIS) (1991)

ORION-2 is a commercially available, federated, object-oriented database management system designed and implemented at MCC. One major architectural innovation in ORION-2 is the coexistence of a shared databese and a number of private databases. The shared database is accessible to all authorized users of the system, while each private database is accessible to only the user who owns it. A distributed database system with a shared database and private databases for individual users is a natural architecture for data-intensive application environments on a network of workstations, notably computer-aided design and engineering systems. This paper discusses the benefits and limitations of such a system and explores the impact of such an architecture on the semantics and implementation of some of the key functions of a database system, notably queries, database schema, and versions. Although the issues are discussed in the context of an object-oriented data model, the results (at least significant portions thereof) are applicable to database systems supporting other data models.
An implementation for small databases with high availability
Authors: Kwok-yan Lam
Venue: ACM SIGOPS Operating Systems Review (1991)

A technique for implementing the kind of small databases that frequently occur in the design of operating systems and distributed systems is presented. This technique is based on the checkpointing mechanism for maintaining data persistence. It can be regarded as a hybrid of the stable storage approach and the master-slave approach to fault tolerance, and is especially suitable for systems that support the processor pool paradigm of computation. This scheme has been used to implement a monitoring service for a distributed system. The resulting implementation has the desired property of being simultaneously simple, efficient, reliable, and available.
Modula-2 an alternative to C?
Authors: Jürgen Angele, Detlef Küpper
Venue: ACM SIGPLAN Notices (1992)

The programming languages C and Modula-2 are compared using criteria significant for efficiently constructing medium and large size commercial software systems. These criteria are motivated in section 2. Section 3 contrasts the features of the two languages which are relevant for the differences.
The Future of Fiber-Optic Computer Networks
Authors: Paul E. Green
Venue: Computer (1991)

The author discusses research activities in the area of third-generation (all-optical) fiber-optic networks and where they are heading. Applications, the era of single unrepeated links, the characteristics of fiber paths in networks, forms of addressing, overall network throughput capacity, technologies, protocol layers, and making the communication layers invisible are discussed.
An analytical approach to floorplan design and optimization
Authors: Suphachai Sutanthavibul, Eugene Shragowitz, J. Ben Rosen
Venue: Proceedings of the 27th ACM/IEEE Design Automation Conference (1991)

An analytical method for general floorplan design and optimization is proposed. This method is based on a mixed integer programming model and application of a standard mathematical software. The method allows arbitrary combinations of rigid and flexible modules. Various objective functions such as chip area, interconnection length, timing delays or any combinations of them are permitted. Routing space is estimated by the global router. Experimental data are provided.
New Multipliers Modulo 2/sup N/-1
Authors: Alexander Skavantzos, Poornachandra B. Rao
Venue: IEEE Transactions on Computers (1992)

Techniques for computing the product of two N-bit integers modulo 2/sup N/-1 from their k-bit byte decompositions are presented. A modulus 2/sup N/-1 is chosen, as multiplication performed in this modulus can be reconstructed from the cyclic convolution between the sequences of the k-bit bytes of the decomposed numbers. It is shown that cyclic convolutions can be computed using only additions and squaring operations but not two-operand multiplications. Since the squaring operation is a one-operand operation, significant savings in ROM bits can be obtained if look-up tables are used.
Recognizing Sources of Random Strings
Authors: R. S. Valiveti, B. J. Oommen
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1991)

The identification of a source given a sequence of random strings is discussed. Two modes of random string generation are analyzed. In the first mode, arbitrary strings are generated in which the individual symbols occur exactly once in each random string. The latter case corresponds to the situation in which the sources generate random permutations. In both cases, the best match to the distribution being used by each source can be obtained by maintaining an exponential number of statistics. This being infeasible, a simple parameterization of the distributions is proposed. For arbitrary strings, the simple unigram-based model (U-model) is proposed. For the case of permutations, a new model called the S-model is proposed, and it is used to analyze and/or approximate unknown distributions of permutations. The relevant estimation procedures, together with the applications to source recognition, are presented. The method presents a unique blend of syntactic and statistical pattern recognition.
Security services in the OSI reference model
Authors: Marie A. Wright
Venue: ACM SIGSAC Review (1992)

As open systems interconnection (OSI) technology establishes global standards for data communications, security is becoming an increasingly important issue for open systems and computer networks. This paper provides an overview of the OSI Reference Model, and discusses the placement of security services in this model.
Performance analysis of the CM-2, a massively parallel SIMD computer
Authors: Jukka Helin
Venue: Proceedings of the 6th international conference on Supercomputing (1992)

The performance evaluation process for a massively parallel distributed memory SIMD computer is described generally. The performance in basic computation, grid communication, and computation with grid communication is analyzed. A practical performance evaluation and analysis study is done for the Connection Machine 2 and conclusions about its performance are drawn.
The Utility of Knowledge in Inductive Learning
Authors: Michael Pazzani, Dennis Kibler
Venue: Machine Learning (1992)

In this paper, we demonstrate how different forms of background knowledge can be integrated with an inductive method for generating function-free Horn clause rules. Furthermore, we evaluate, both theoretically and empirically, the effect that these forms of knowledge have on the cost and accuracy of learning. Lastly, we demonstrate that a hybrid explanation-based and inductive learning method can advantageously use an approximate domain theory, even when this theory is incorrect and incomplete.
Searching for historical word-forms in a database of 17th-century English text using spelling-correction methods
Authors: Alexander M. Robertson, Peter Willett
Venue: Proceedings of the 15th annual international ACM SIGIR conference on Research and development in information retrieval (1992)

This paper discusses the application of algorithmic spelling-correction techniques to the identification of those words in a database of 17th century English text that are most similar to a query word in modern English. The experiments have used n-gram matching, non-phonetic coding and dynamic programming methods for spelling correction, and have demonstrated that high-recall searches can be carried out, although some of the searches are very demanding of computational resources. The methods are, in principle, applicable to historical texts in many languages and from many diffeent periods.
An agenda for human-computer interaction: science and engineering serving human needs
Authors: Gary Marchionini, John Sibert
Venue: ACM SIGCHI Bulletin (1991)

Human-computer interaction (HCI) research is concerned with the design of interfaces that allow easy and efficient use of computer systems. This report is the result of a workshop held to define the state of the art and to identify HCI research directions. The workshop was held on March 4 and 5, 1991 at George Washington University. The participants considered four areas of HCI research: theory and models; input/output devices; tools and architectures; and computer-supported cooperative work (CSCW). This report contains information about each of these areas.
Industrial strength compiler construction with equations
Authors: Lutz H. Hamel
Venue: ACM SIGPLAN Notices (1992)

Industrial strength compilers need not only be robust and efficient but also understandable, maintainable, and extensible. To make compilers more manageable there has been a strong trend towards the high-level specification of the different phases of the compilation process. However, the high-level specification of one phase - the semantic analysis - has not been very successful in terms of production quality standards. In this paper we propose the use of a language based on equations for the specification of the semantic analysis phase of compilers.
The impact of new accreditation and certification standards for secondary computer science teachers on university computer science departments
Authors: Harriet G. Taylor, C. Dianne Martin
Venue: ACM SIGCSE Bulletin (1992)

The establishment of accreditation and certification standards for secondary computer science teachers has been taking place over the past 5 years. The ACM has taken the lead in developing certification standards for adoption by states and the International Society for Technology in Education (ISTE) has taken the lead in developing national accreditation standards for teacher preparation programs through affiliation with NCATE, the accrediting body for professional education units in the USA. The impact of institutionalizing these new standards is discussed, and the role that university computer science departments should now take in the teacher preparation process is described.
The Twisted N-Cube with Application to Multiprocessing
Authors: Abdol-Hossein Esfahanian, Lionel M. Ni, Bruce E. Sagan
Venue: IEEE Transactions on Computers (1991)

It is shown that by exchanging any two independent edges in any shortest cycle of the n-cube (n
Performance Analysis of Virtual Cut-Through Switching in HARTS: A Hexagonal Mesh Multicomputer
Authors: James W. Dolter, P. Ramanathan, Kang G. Shin
Venue: IEEE Transactions on Computers (1991)

The authors present a formal analysis of virtual cut-through in a C-wrapped hexagonal mesh multicomputer, called the HARTS (hexagonal architecture for real-time systems). In virtual cut-through, packets arriving at an intermediate node are forwarded to the next node in the route without buffering if a circuit can be established to the next node. The hexagonal mesh is first characterized using a combinatorial analysis to determine the probability that a packet will establish a cut-through at an intermediate node. Given this parameter the probability distribution function for packet delivery times in HARTS is derived. The delivery times obtained from the analytic model are then compared against results collected from a simulator of the routing hardware designed for use in HARTS. The results from both the analytic model and the simulator further reinforce the choice of the virtual cut-through routing scheme for use in HARTS.
Nonblocking Broadcast Switching Networks
Authors: Yuanyuan Yang, Gerald M. Masson
Venue: IEEE Transactions on Computers (1991)

Results are presented for nonblocking multistage broadcast networks wherein a request from an idle input port to be connected to some set of idle output ports can be satisfied without any disturbance of other broadcast connections already existing in the network. Furthermore, a linear network control algorithm for realizing such a broadcast connection request is given. These results represent the best known explicit constructions with limited numbers of stages relative to both crosspoint and control algorithm complexity. Thus, these networks are highly useful for practical applications involving the movement of and collaboration with voice/video/text/graphics information that require broadcast capability. These networks are also useful for the interconnection of processor and memory units in parallel processing systems.
Degrees of inferability
Authors: Peter Cholak, Efim Kinber, Rod Downey, Martin Kummer, Lance Fortnow, Stuart Kurtz, William Gasarch, Theodore A. Slaman
Venue: Proceedings of the fifth annual workshop on Computational learning theory (1992)

Most theories of learning consider inferring a function f from either (1) observations about f or, (2) questions about f. We consider a scenario whereby the learner observes f and asks queries to some set A. EX[A] is the set of concept classes EX-learnable by an inductive inference machine with oracle A. A and F are EX-equivalent if EX[A] = EX[B]. The equivalence classes induced are the degrees of inferability. We prove several results about these degrees: (1) There are an uncountable number of degrees. (2) For A r.e., REC &egr; BC[A] iff 0slash;&huml; &le;T A&acute;, and there is evidence this holds for all sets A. (3) For A, B r.e., A &equiv;T Biff EX[A] = EX[B]. (4) There exists A, B low2 r.e., A|RB, EX[A] = EX[B]. (hence (3) is optimal).
Reflections on Shading
Authors: David Forsyth, Andrew Zisserman
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1991)

It is demonstrated that mutual illumination can produce significant effects in real scenes. An example is presented to illustrate the difficulties that mutual illumination presents to shape recovery schemes. These effects are qualitatively modeled by the radiosity equation. Using the radiosity equation, the authors predict the occurrence of spectral events in the radiance, namely, discontinuities in the radiance and its derivatives. Experimental evidence establishes the validity of this approach. Mutual illumination can generate discontinuities in the derivatives of radiance unrelated to local geometry. It is argued that it is not possible to obtain veridical dense depth or normal maps from a shading analysis. However, discontinuities in radiance are tractably related to scene geometry and, moreover, can be detected.
An application of computer algebra to a problem in stratified fluid flow
Authors: Robert J. Yamartino, Richard Pavelle
Venue: Journal of Symbolic Computation (1991)

The computationally tedious problem of considering trial Green's function solutions to the fourth-order partial differential equation for a stratified atmosphere flowing over a hill is approached using MACSYMA. Significance of the problem, solution methodologies and CPU time intercomparisons using various computer platforms and other algebra systems are discussed.
Assessing the quality of hypertext views
Authors: P. D. Bruza, Th. P. van der Weide
Venue: ACM SIGIR Forum (1990)

In this article the problem of assessing the quality of hypertext views is considered. This is done in terms of a formal model of hypertext in which the view is a central aspect. The objects in a view are described in terms of so called index expressions which are a powerful object characterization mechanism. These characterizations are manipulated by a calculus, which allows quantification of notions such as cohesion and relevance. These latter are useful criteria for judging the quality of a view.
Reviving systems programming
Authors: J. L. Wolfe
Venue: Proceedings of the twenty-third SIGCSE technical symposium on Computer science education (1992)

This paper describes how a systems programming course, which was losing popularity with students and which no longer fit into the curriculum, was revised so that it made a contribution to the overall program. The principal changes were to replace a large, well-worn project with a collection of small challenges and to alter radically the content, presentation, support, and grading of these challenges (in comparison to typical assignments). The resulting course amalgamates traditional systems programming and systems programming as it is done on the job.
On the determination of Green's relations in finite transformation semigroups
Authors: Gerard Lallement, Robert Mcfadden
Venue: Journal of Symbolic Computation (1990)

This paper contains an algorithm which, on input the set of generators of a transformation semigroup S on a finite set, gives all Green's relations on S, a set of generators for the maximal subgroups of S, and a complete determination of the partially ordered set of all the -classes of S. The algorithm is based on an earlier technique of J. F. Perrot for studying regular -classes and on new results on non-regular -classes allowing for a systematic search for all the -classes of S.
ALEX: an aid to teaching algorithms
Authors: Sean Pyott, Ian Sanders
Venue: ACM SIGCSE Bulletin (1991)

A problem with teaching Computer Science to first-year students in a South African context is that many students come from disadvantaged backgrounds and have not been exposed to computer technology. To address this issue, a new curriculum has been adopted for first-year students, the first topic of which covers the design and specification of algorithms. One of the problems encountered in this course is that if the students cannot execute their algorithms they do not know whether the algorithms are correct. One approach to this problem is to require that students be familiar with a programming language. This paper investigates an alternative way of executing algorithms, the ALEX system, and discusses how the system can be used to assist in the teaching of algorithms.ALEX allows students to specify algorithms in an English-like manner and translates these algorithms into an equivalent executable high-level language code, which is then executed. Based on the evaluation of individual students, the use of ALEX is beneficial. However, further experimentation has to occur before the effectiveness of using ALEX can be properly assessed.
Stationary likelihood ratios and smoothed perturbation analysis gradient estimates for the routing problem
Authors: P. Brémaud, W.-B. Gong
Venue: Proceedings of the 1992 ACM SIGMETRICS joint international conference on Measurement and modeling of computer systems (1992)

We present stationary and regenerative form estimates for the gradients of the cycle variables with respect to a thinning parameter in the arrival process of G/G/1 queueing systems. Our estimates belong to the category of the likelihood ratio method (LRM) and smoothed perturbation analysis (SPA) estimates. The results are useful in adaptive routing design.