ppxscal/embedding_network huggingface dataset:
NP trees and Carnap's modal logic
Authors: Georg Gottlob
Venue: Journal of the ACM (JACM) (1995)

In this paper we consider problems and complexity classes definable by interdependent queries to an oracle in NP. How the queries depend on each other is specified by a directed graph G. We first study the class of problems where G is a general dag and show that this class coincides with Dp2 .We then consider the class where G is a tree. Our main result states that this class is identical to PNP[O(log n)], the class of problems solvable in polynomial time with a logarithmic number of queries to an oracle in NP. This result has interesting applications in the fields of modal logic and artificial intelligence. In particular, we show that the following problems are all PNP[O(log n)] complete: validity-checking of formulas in Carnap's modal logic, checking whether a formula is almost surely valid over finite structures in modal logics K, T, and S4 (a problem recently considered by Halpern and Kapron [1992]), and checking whether a formula belongs to the stable set of beliefs generated by a propositional theory.We generalize the case of dags to the case where G is a general (possibly cyclic) directed graph of NP-oracle queries and show that this class corresponds to Pp2 . We show that such graphs are easily expressible in autoepistemic logic. Finally, we generalize our complexity results to higher classes of the polynomial-time hierarchy.
Architectural optimizations to advanced distributed simulation
Authors: Larry Mellon, Darrin West
Venue: Proceedings of the 27th conference on Winter simulation (1995)

Current DoD mechanisms to support distributed simulations have reached their limits in terms of size and fidelity. Several projects are underway to improve the state of the art in the DoD, defining a new class of distributed simulation: advanced distributed simulation (ADS). This paper presents an architectural view of the problem area, i.e. identifying the conceptual objects in an ADS system, and describing their responsibilities and interactions. Classes of data transmission optimizations are identified and discussed in terms of scalability, flexibility, and current research efforts.
Solving satisfiability and implication problems in database systems
Authors: Sha Guo, Wei Sun
Venue: ACM Transactions on Database Systems (TODS) (1996)

Satisfiability, implication, and equivalence problems involving conjunctive inequalities are important and widely encountered database problems that need to be efficiently and effectively processed. In this article we consider two popular types of arithmetic inequalities, (XopY) and (X op C), where X and Y are attributes, C is a constant of the domain or X, and op &isin;{<, &le;, =, &ne;, >, &ge;). These inequalities are most frequently used in a database system, inasmuch as the former type of inequality represents a 0-join, and the latter is a selection. We study the satisfiability and implication problems under the integer domain and the real domain, as well as under two different operator sets ({<, &le;, =, &ge;, >} and {<, &le;, =, &ne;, &ge;, >}). Our results show that solutions under different domains and/or different operator sets are quite different. Out of these eight cases, excluding two cases that had been shown to be NP-hard, we either report the first necessary and sufficient conditions for these problems as well as their efficient algorithms with complexity analysis (for four cases), or provide an improved algorithm (for two cases). These iff conditions and algorithms are essential to database designers, practitioners, and researchers. These algorithms have been implemented and an experimental study comparing the proposed algorithms and those previously known is conducted. Our experiments show that the proposed algorithms are more efficient than previously known algorithms even for small input. The C++ code can be obtained by an anonymous ftp from <archive.fiu.edu>.
Undergraduate AI and its non-imperative prerequisite
Authors: Deepak Kumar, Richard Wyatt
Venue: ACM SIGART Bulletin (1995)

This position paper presents, we believe, a strong case for including in an undergraduate Computer Science (CS) program a required course in non-imperative programming. Such a course is motivated by the need to provide a uniform and adequate background for a course in Artificial Intelligence (AI). We make no claim about graduate AI courses. We survey the recommendations of the ACM-IEEE Joint Curriculum Task Force for an undergraduate course in AI and argue that some of the "dilemmas" of teaching introductory AI courses can be resolved by changes in the core CS curriculum. The argument for such a course is the focus of the paper; we also offer some ancillary remarks on other matters relating to teaching AI at the introductory level.
Bounding the Subspaces from Rank Revealing Two-Sided Orthogonal Decompositions
Authors: Ricardo D. Fierro, James R. Bunch
Venue: SIAM Journal on Matrix Analysis and Applications (1995)

The singular value decomposition (SVD) is a widely used computational tool in various applications. However, in some applications the SVD is viewed as computationally demanding or difficult to update. The rank revealing QR (RRQR) decomposition and the recently proposed URV and ULV decompositions are promising alternatives for determining the numerical rank $k$ of an $m \times n$ matrix and approximating its fundamental numerical subspaces whenever $k \approx \min(m,n)$. In this paper we prove a posteriori bounds for assessing the quality of the subspaces obtained by two-sided orthogonal decompositions. In particular, we show that the quality of the subspaces obtained by the URV or ULV algorithm depends on the quality of the condition estimator and not on a gap condition. From our analysis we conclude that these decompositions may be more accurate alternatives to the SVD than the RRQR decomposition. Finally, we implement the algorithms in an adaptive manner, which is particularly useful for applications where the "noise" subspace must be computed, such as in signal processing or total least squares.
A Method of Constructing Selection Networks with O(log n) Depth
Authors: S. Jimbo, A. Maruoka
Venue: SIAM Journal on Computing (1996)

A classifier with $n$ inputs is a comparator network that classifies a set of $n$ values into two classes with the same number of values in such a way that each value in one class is at least as large as all of those in the other. Based on the utilization of expanders, Pippenger constructed classifiers with $n$ inputs, whose size is asymptotic to $2n\log_{2}n$. In the same spirit, we obtain a relatively simple method to construct classifiers of depth $O(\log n)$. In consequence, for arbitrary constant $C > 3/\log_2 3 = 1.8927\cdots$, we construct classifiers of depth $O(\log n)$ and of size at most $Cn\log_{2}n + O(n)$.
Creating products customers demand
Authors: Anthony F. Hutchings, Steve T. Knox
Venue: Communications of the ACM (1995)

This article presents a re-engineering case study of the product requirements definition process at Digital Equipment Corporation. Based on cross-functional teams working in direct partnership with customers, the re-engineered process was designed to ensure customer satisfaction and business readiness before a line of code is written, an electronic circuit designed, or a service defined.
The Homology of Partitions with an Even Number of Blocks
Authors: Sheila Sundaram
Venue: Journal of Algebraic Combinatorics: An International Journal (1995)

Let \Pi_{2n}^e denote the subposet obtained by selecting even ranks in the partition lattice \Pi_{2n}. We show that the homology of \Pi_{2n}^e has dimension {{(2n)!}\over {2^{2n-1}}} E_{2n-1}, where E_{2n-1} is the tangent number. It is thus an integral multiple of both the Genocchi number and an Andr&eacute; or simsun number. Using the general theory of rank-selected homology representations developed in &lsqb;22&rsqb;, we show that, for the special case of \Pi_{2n}^e, the character of the symmetric group S2n on the homology is supported on the set of involutions. Our proof techniques lead to the discovery of a family of integers bi(n), 2 &le; i &le; n, defined recursively. We conjecture that, for the full automorphism group S2n, the homology is a sum of permutation modules induced from Young subgroups of the form S^i_2 \times S^{2n-2i}_1, with nonnegative integer multiplicity bi(n). The nonnegativity of the integers bi(n) would imply the existence of new refinements, into sums of powers of 2, of the tangent number and the Andr&eacute; or simsun number an(2n).Similarly, the restriction of this homology module to S2n&minus;1 yields a family of integers di(n), 1 &le; i &le; n &minus; 1, such that the numbers 2&minus;idi(n) refine the Genocchi number G2n. We conjecture that 2&minus;idi(n) is a positive integer for all i.Finally, we present a recursive algorithm to generate a family of polynomials which encode the homology representations of the subposets obtained by selecting the top k ranks of \Pi_{2n}^e, 1 &le; k &le; n &minus; 1. We conjecture that these are all permutation modules for S2n.
Evaluation of the CyberGlove as a whole-hand input device
Authors: G. Drew Kessler, Larry F. Hodges, Neff Walker
Venue: ACM Transactions on Computer-Human Interaction (TOCHI) (1995)

We present a careful evaluation of the sensory characteristics of the CyberGlove model CG1801 whole-hand input device. In particular, we conducted an experimental study that investigated the level of sensitivity of the sensors, their performance in recognizing angles, and factors that affected accuracy of recognition of flexion measurements. Among our results, we show that hand size differences among the subjects of the study did not have a statistical effect on the accuracy of the device. We also analyzed the effect of different software calibration approaches on accuracy of the sensors.
Global analysis of constraint logic programs
Authors: M. Garcia de la Banda, M. Hermenegildo, M. Bruynooghe, V. Dumortier, G. Janssens, W. Simoens
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1996)

This article presents and illustrates a practical approach to the dataflow analysis of constraint logic programming languages using abstract interpretation. It is first argued that, from the framework point of view, it suffices to propose relatively simple extensions of traditional analysis methods which have already been proved useful and practical and for which efficient fixpoint algorithms exist. This is shown by proposing a simple extension of Bruynooghe's traditional framework which allows it to analyze constraint logic programs. Then, and using this generalized framework, two abstract domains and their required abstract functions are presented: the first abstract domain approximates definiteness information and the second one freeness. Finally, an approach for combining those domains is proposed. The two domains and their combination have been implemented and used in the analysis of CLP(R) and Prolog-III applications. Results form this implementation showing its performance and accuracy are also presented.
The first-course conundrum
Authors: Hal Abelson, Kim Bruce, Andy van Dam, Brian Harvey, Allen Tucker, Peter Wegner
Venue: Communications of the ACM (1995)

Recently, the College Entrance Examination Board (CEEB) has decided to redesign the Advanced Placement (AP) examination in computer science (CS) so that AP courses will be forced to switch from Pascal to C++ starting around 1998.
Compact Representations of Videos Through Dominant and Multiple Motion Estimation
Authors: Harpreet S. Sawhney, Serge Ayer
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1996)

An explosion of on-line image and video data in digital form is already well underway. With the exponential rise in interactive information exploration and dissemination through the World-Wide Web (WWW), the major inhibitors of rapid access to on-line video data are costs and management of capture and storage, lack of real-time delivery, and nonavailability of content-based intelligent search and indexing techniques. The solutions for capture, storage, and delivery may be on the horizon or a little beyond. However, even with rapid delivery, the lack of efficient authoring and querying tools for visual content-based indexing may still inhibit as widespread a use of video information as that of text and traditional tabular data is currently.In order to be able to nonlinearly browse and index into videos through visual content, it is necessary to develop authoring tools that can automatically separate moving objects and significant components of the scene, and represent these in a compact form. Given that video data comes in torrents¿almost a megabyte every 30th of a second¿it will be highly inefficient to search for objects and scenes in every frame of a video. In this paper, we present techniques to automatically derive compact representations of scenes and objects from the motion information.Image motion is a significant cue in videos for the separation of scenes into their significant components and for the separation of moving objects. Motion analysis is useful in capturing the visual content of videos for indexing and browsing in two different ways. First, separation of the static scene from moving objects can be accomplished by employing dominant 2D/3D motion estimation methods. Alternatively, if the goal is to be able to represent the fixed scene too as a composition of significant structures and objects, then simultaneous multiple motion methods might be more appropriate. In either case, view-based summarized representations of the scene can be created by video compositing/mosaicing based on the estimated motions. We present robust algorithms for both kinds of representations: 1) dominant motion estimation based techniques which exploit a fairly common occurrence in videos that a mostly fixed background (scene) is imaged with or without independently moving objects, and 2) simultaneous multiple motion estimation and representation of motion video using layered representations. Ample examples of the representations achieved by each method are included in the paper.
Recycling APL code into client/server applications
Authors: Richard J. Busman, Walter G. Fil, Andrei V. Kondrashev
Venue: ACM SIGAPL APL Quote Quad (1995)

This paper analyzes the current state of modern APL and deals with the authors' experiences in recycling and downsizing old APL applications and transforming them into more open information systems using client/server technology on different hardware and software platforms.
Object design for communication protocol software
Authors: Chung-Shyan Liu
Venue: ACM SIGPLAN OOPS Messenger (1995)

In this paper, an object design method for communication protocol software, which is specified based on a finite state machine, is presented. In our method, an object class is defined for each state of the finite state machine. The objects designed in our method have freer granularity than that in conventional approaches. Inheritance is used in our method as a program structuring mechanism to allow incremental design. A real example is given for demonstration.
Dynamic fault-tolerant clock synchronization
Authors: Danny Dolev, Joseph Y. Halpern, Barbara Simons, Ray Strong
Venue: Journal of the ACM (JACM) (1995)

This paper gives two simple efficient distributed algorithms: one for keeping clocks in a network synchronized and one for allowing new processors to join the network with their clocks synchronized. Assuming a fault-tolerant authentication protocol, the algorithms tolerate both link and processor failures of any type. The algorithm for maintaining synchronization works for arbitrary networks (rather than just completely connected networks) and tolerates any number of processor or communication link faults as long as the correct processors remain connected by fault-free paths. It thus represents an improvement over other clock synchronization algorithms such as those of Lamport and Melliar Smith and Welch and Lynch, although, unlike them, it does require an authentication protocol to handle Byzantine faults. Our algorithm for allowing new processors to join requires that more than half the processors be correct, a requirement that is provably necessary.
Programming Language Support for Writing Fault-Tolerant Distributed Software
Authors: Richard D. Schlichting, Vicraj T. Thomas
Venue: IEEE Transactions on Computers (1995)

Good programming language support can simplify the task of writing fault-tolerant distributed software. Here, an approach to providing such support is described in which a general high-level distributed programming language is augmented with mechanisms for fault tolerance. Unlike approaches based on sequential languages or specialized languages oriented towards a given fault-tolerance technique, this approach gives the programmer a high level of abstraction, while still maintaining flexibility and execution efficiency. The paper first describes a programming model that captures the important characteristics that should be supported by a programming language of this type. It then presents a realization of this approach in the form of FT-SR, a programming language that augments the SR distributed programming language with features for replication, recovery, and failure notification. In addition to outlining these extensions, an example program consisting of a data manager and its associated stable storage is given. Finally, an implementation of the language that uses the $\mbi{x}$-kernel and runs standalone on a network of Sun workstations is discussed. The overall structure and several of the algorithms used in the runtime are interesting in their own right.
The interface between simulation output analysis research and practice
Venue: Proceedings of the 27th conference on Winter simulation (1995)

Summary form only given. Academic researchers are urged by their sponsors to demonstrate the relevance of their work. Software suppliers are pressured by market competition to keep their products current with the state of the art. The goal of this panel is to find new ways to strengthen the connection between research and practice.
The solution of multidimensional real Helmholtz equations on Sparse Grids
Authors: Robert Balder, Christoph Zenger
Venue: SIAM Journal on Scientific Computing (1996)

Sparse grids provide a very efficient method for the multilinear approximation of functions, especially in higher-dimensional spaces. In the $d$-dimensional space, the nodal multilinear basis on a grid with mesh size $h = 2^{-n}$ consists of $O(2^{nd})$ basis functions and leads to an $L\_2$-error of order $O(4^{-n})$ and an $H\_1$-error of order $O(2^{-n})$. With sparse grids we get an $L\_2$-error of order $O(4^{-n}n^{d-1})$ and an $H\_1$-error of order $O(2^{-n})$ with only $O(2^n n^{d-1})$ basis functions, if the function $u$ fulfills the condition ${\partial^{2d} \over {\partial x_1^2}{\partial x_2^2} \ldots {\partial x_d^2}} uA data structure for the sparse grid representation of functions defined on cubes of arbitrary dimension and a finite element approach for the Helmholtz equation with sparse grid functions are introduced. Special emphasis is taken in the development of an efficient algorithm for the multiplication with the stiffness matrix. With an appropriate preconditioned conjugate gradient method (cg-method), the linear systems can be solved efficiently. Numerical experiments are presented for Helmholtz equations and eigenvalue problems for the Laplacian in two and three dimensions, and for a six-dimensional Poisson problem. The results support the assertion that the $L\_2$-error bounds for the sparse-grid approximation are also valid for sparse grid finite element solutions of elliptic differential equations. Problems with nonsmooth solutions are treated with adaptive sparse grids.
Relief characters by micro capsule paper
Authors: Nobuyuki Ohtake, Yasuhiko Ogawa, Yoshimichi Yonezawa
Venue: Issue 51 (January 1995) (1995)

Micro capsule paper has been developed by Yonezawa [6, 7] for tactile pattern. To learn printed Chinese characters (called "Kanji" in Japanese), several relief characters have been prepared to enable the blind to study these complicated printed characters by this micro capsule paper. All prepared characters (alphabet, braille patterns, Kanji) data for micro capsule paper are converted PostScript language[1] by a developed tool. Although this matter has been thought of a local topic in Kanji cultural area, hidden problems containing some common subjects exist in all forms of written language. There are several communication tools (braille, telephone, audio equipments, etc hellip;) for the blind, especially Optacon (optical to tactile converter) is one of a few equipment which reads visual information. To realize the original printed characters is an essential matter when the blind use the Optacon. In any case, people who do not have basic knowledge about printed characters can not understand anything. And it is important for the blind to understand written language, so original character learning is a matter of great essentials. However learning Kanji characters is a Japanese problem, the research and discussion in this paper also contain practical applications and common problems for other written language.
Automated Refinement of First-Order Horn-Clause Domain Theories
Authors: Bradley L. Richards, Raymond J. Mooney
Venue: Machine Learning (1995)

Knowledge acquisition is a difficult, error-prone, and time-consuming task. The task of automatically improving an existing knowledge base using learning methods is addressed by the class of systems performing theory refinement. This paper presents a system, forte (First-Order Revision of Theories from Examples), which refines first-order Horn-clause theories by integrating a variety of different revision techniques into a coherent whole. FORTE uses these techniques within a hill-climbing framework, guided by a global heuristic. It identifies possible errors in the theory and calls on a library of operators to develop possible revisions. The best revision is implemented, and the process repeats until no further revisions are possible. Operators are drawn from a variety of sources, including prepositional theory refinement, first-order induction, and inverse resolution. FORTE is demonstrated in several domains, including logic programming and qualitative modelling.