ppxscal/embedding_network huggingface dataset:
Square Meshes are Not Always Optimal
Authors: Amotz Bar-Noy, David Peleg
Venue: IEEE Transactions on Computers (1991)

Mesh-connected computers with multiple buses providing broadcast facilities along rows and columns are discussed. A tight bound of Theta (n/sup 1/8/) is established for the number of rounds required for semigroup computations on n values distributed on a two-dimensional rectangular mesh of size n with a bus on every row and column. The upper bound is obtained for a skewed rectangular mesh of dimensions n/sup 3/8/*n/sup 5/8/. This result is compared to the tight bound of Theta (n/sup 1/6/) for the same problem on the square (n/sup 1/2/*n/sup 1/2/) mesh. It is shown that in the presence of multiple buses, a skewed configuration may perform better than a square configuration for certain computational tasks. The result can be extended to the d-dimensional mesh, giving a lower bound of Omega (n/sup 1/d alpha /) and an upper bound of O(d2/sup d+1/ n/sup 1/d alpha /), where alpha =2/sup d/; these bounds are optimal within constant factors for any constant d. It is noted that for d
Thick selective epitaxial growth of silicon at 960°C using silane only
Authors: N. Afshar-Hanaii, J. M. Bonar, A. G. R. Evans, G. J. Parker, C. M. K. Starbuck, H. A. Kemhadjian
Venue: Microelectronic Engineering (1992)

Selective epitaxial layers of silicon have been successfully grown in a chlorine-free system. An optimum set of growth conditions has been found under which selective layers of up to 1 @mm can be achieved. Excellent thickness uniformity (less than 5% standard deviation) across the wafer and from run to run has been achieved in windows as small as 1 @mm, without any loading effect. In features with sidewalls aligned along the direction, faceting is less pronounced as compared to features aligned along the direction. The technology is promising for the fabrication of future ULSI devices, utilizing selective epitaxial growth of silicon.
Characterization of database access skew in a transaction processing environment
Authors: Asit Dan, Philip S. Yu, Jen-Yao Chung
Venue: Proceedings of the 1992 ACM SIGMETRICS joint international conference on Measurement and modeling of computer systems (1992)

The knowledge of access skew (non-uniform access) in each database relation is useful for both workload management (buffer pool allocation, transaction routing, etc.), as well as capacity planning for changing workload mix. However, it is a challenging problem to characterize the access skew of a real database workload in a simple manner that can easily be used to compute the buffer hit probability under the LRU replacement policy. A concise way to characterize the access skew is proposed by assuming that the large number of data pages may be logically grouped into a small number of partitions such that the frequency of accessing each page within a partition can be treated as equal. Based on this approach, a recursive binary partitioning algorithm is presented that can infer the access skew from the buffer hit probabilities for a subset of the buffer sizes. This avoids explicit estimation of individual access frequencies for the large number of database pages. The method is validated of its ability to predict buffer hit from the skew characterization using production database traces.
Towards a model of cognitive process in logical design: comparing object-oriented and traditional functional decomposition software methodologies
Authors: Jinwoo Kim, F. Javier Lerch
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems (1992)

This study aims at developing and empirically testing hypotheses about professional designers' cognitive activities when using object-oriented methodology (OOD) versus using traditional functional decomposition methodologies (TFD). Our preliminary results indicate that OOD may achieve substantial time savings over TFD in logical design. The verbal protocols from a pilot study show that OOD may achieve these time savings: 1) by simplifying rule induction processes used in functional decomposition; 2) by guiding designers on how to build more effective problem spaces; and 3) by allowing designers to run mental simulation more efficiently and more effectively.
A national debate on encryption exportability
Authors: Clark Weissman
Venue: Communications of the ACM (1991)

Traditionally, cryptography has been an exclusively military technology controlled by the National Security Agency (NSA). Therefore, U.S. International Traffic in Arms Regulations (ITARS) requires licenses for all export of modern cryptographic methods. Some methods, such as the Data Encryption Standard (DES), are easily obtained for export to the Coordinating Committee for Multilateral Export Controls (COCOM) countries, but not Soviet block countries, or most Third World nations.
A global, dynamic register allocation and binding for a data path synthesis system
Authors: Nam-Sung Woo
Venue: Proceedings of the 27th ACM/IEEE Design Automation Conference (1991)

We developed a new algorithm for efficient register allocation and binding used in data path synthesis. Our algorithm determines both the number of registers and the mapping from variables to registers simultaneously during data path allocation so that the cost, i.e., area, of the registers and connections to/from the registers can be minimized. The algorithm selects the &ldquo;best&rdquo; register for each input and/or output variable of operations. This register allocation/binding algorithm is used with a data path allocation algorithm that exploits trade-off among all kinds of hardware elements. We present experimental results of our algorithm.
Shape Representation by Multiscale Contour Approximation
Authors: Ann Bengtsson, Jan-Olof Eklundh
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1991)

An approach is presented for deriving qualitative descriptions of contours containing structures at different (unknown) scales. The descriptions are in terms of straight arcs, curved arcs with sign of curvature, corners, and points delimiting the arcs: inflexion points and transitions from straight to curved. Furthermore, the tangents at these points are derived. The approach is based on the construction of a hierarchic family of polygons, having the scale-space property of causality; structure can only disappear as scale goes from fine to coarse. Using the principle that structures that are stable over scale represent significant properties, the features of the descriptive representations are then derived.
Communication types
Authors: C. Jung, E. Sibert
Venue: ACM SIGPLAN Notices (1990)

Indirect naming of processes in the distributed message communication can be achieved either by introducing channels or ports (channel oriented scheme) or by using process variables (process oriented scheme). The communication type is introduced on top of the process oriented scheme in order to achieve the same degree of static checking on legitimate communication between processes as the channel oriented scheme. This can be done without introducing a passive shared object in the language semantics which is a major disadvantage of the channel oriented scheme, in a distributed message communication environment.
Probabilistic state machines: dialog management for inputs with uncertainty
Authors: Scott E. Hudson, Gary L. Newell
Venue: Proceedings of the 5th annual ACM symposium on User interface software and technology (1992)

Traditional models of input work on the assumption that inputs delivered to a system are fairly certain to have occurred as they are reported. However, a number of new input modalities, such as pen-based inputs, hand and body gesture inputs, and voice input, do not share this property. Inputs under these techniques are normally acquired by a process of recognition. As a result, each of these techniques makes mistakes and provides inputs which are approximate or uncertain. This paper considers some preliminry techniques for dialog management in the presence of this uncertainty. These techniques&mdash;including a new input model and a set of extended state machine abstractions&mdash;will explicitly model uncertainty and handle it as a normal and expected part of the input process.
Toward a diagnostic instrument for assessing the quality of expert systems
Authors: David W. Conrath, Ravi S. Sharma
Venue: ACM SIGMIS Database (1992)

In this article we discuss the problem of evaluating the quality of expert systems. The solution we propose is a diagnostic instrument that assesses the relative strengths and weaknesses of an operational expert system. Such a tool is designed to identify the characteristics and features that determine the system's quality (or lack of it) as a means of supporting the knowledge engineering process. Our approach is based on underlying concepts form socio-technical theory. It is also empirically subjected to a rigorous validation methodology.
Dining philosophers revisited, again
Authors: Kwok-bun Yue
Venue: ACM SIGCSE Bulletin (1991)

This paper describes a problem in the solution of the dining philosophers problem by Gingras [2] that makes it inefficient, instead of the claimed maximal efficiency. A correct implementation is presented. Even then, the solution has other undesirable characteristics and is still not maximally efficiency. Depending on the definition of efficiency, it may not be possible to attain maximal efficiency and be starvation-free at the same time. A better and simpler solution for general mutual exclusion problems, in which the dining philosophers problem is a special case, is presented. This solution can become symmetric if appropriate data structures are used.
Structural ambiguity and lexical relations
Authors: Donald Hindle, Mats Rooth
Venue: Proceedings of the workshop on Speech and Natural Language (1990)

From a certain (admittedly narrow) perspective, one of the annoying features of natural language is the ubiquitous syntactic ambiguity. For a computational model intended to assign syntactic descriptions to natural language text, this seem like a design defect. In general, when context and lexical content are taken into account, such syntactic ambiguity can be resolved: sentences used in context show, for the most part, little ambiguity. But the grammar provides many alternative analyses, and gives little guidance about resolving the ambiguity.
Inkwell: A 2-D animation system
Authors: Peter C. Litwinowicz
Venue: ACM SIGGRAPH Computer Graphics (1991)

Inkwell, an experimental 2 1/2-D keyframe animation system, is the subject of this paper. Inkwell provides an intuitive user interface for creating and animating polygons, ellipses and splines. These primitives may be outlined and filled with a variety of patterns to create animated diagrams, graphs and charts, and simple characters and cartoons. Inkwell also has a patch primitive that facilitates deformation and animation of textured regions. The system provides editing features that include shape and timing control as well as digital filtering of parameters. Finally, Inkwell has deformation primitives that enable an animator to warp geometry in an intuitive manner. Inkwell was used to produce Pigment Promenade, a computer animated short shown at SIGGRAPH 1990.
Implementation of information system design specifications: a performance perspective
Authors: Brian Nixon
Venue: Proceedings of the third international workshop on Database programming languages : bulk types persistent data: bulk types persistent data (1992)

Suppose you are given a conceptual design specification for an information system, written in an entity-based specification language which supports features including entity classes, declaratively-defined transactions, and generalisation hierarchies. You are also given some performance requirements, such as &ldquo;minimise the time to reimburse a researcher&rdquo; or &ldquo;minimise storage space for information on meetings.&rdquo; Your task is to generate an implementation (relational database and application programmes) which is consistent with the design specification and meets the performance requirements. We consider the development of a framework to accomplish this task by &ldquo;mapping&rdquo; information system design specifications into implementations. Two issues are addressed. Performance prediction: Given a design specification, a particular implementation of it, and expected usage statistics (e.g., class cardinalities), obtain estimates of performance measures. Selection among implementation alternatives: Given a specification, statistics, and some performance goals, select an efficient implementation (from sets of pre-defined alternatives) by a process of goal decomposition. To structure prediction and selection, we use a multi-layered approach, based on subsets of data model and language features.
Teaching instructional software design
Authors: Greg Kearsley, Rachelle Heller
Venue: ACM SIGCSE Bulletin (1992)

This article describes our approach to teaching graduate students in education and computer science about the design of instructional software. The course is taught by instructional television (ITV) and involves the use of a computer bulletin board system. Students complete software projects using a variety of commercial authoring tools. Student reactions to the nature of the course are described as well as lessons learned.
A Spanning Tree Carry Lookahead Adder
Authors: Thomas Lynch, Earl E. Swartzlander,  Jr.
Venue: IEEE Transactions on Computers (1992)

The design of the 56-b significant adder used in the Advanced Micro Devices Am29050 microprocessor is described. Originally implemented in a 1- mu m design role CMOS process, it evaluates 56-b sums in well under 4 ns. The adder employs a novel method for combining carries which does not require the back propagation associated with carry lookahead, and is not limited to radix-2 trees, as is the binary lookahead carry tree of R.P. Brent and H.T. Kung (1982). The adder also utilizes a hybrid carry lookahead-carry select structure which reduces the number of carriers that need to be derived in the carry lookahead tree. This approach produces a circuit well suited for CMOS implementation because of its balanced load distribution and regular layout.
Fun, rigour and pragmatism in functional programming
Authors: Angel Sánchez-Calle, J. Angel Velázquez-Iturbide
Venue: ACM SIGCSE Bulletin (1991)

A course on functional programming using Hope is presented. It describes the basic principles of functional programming, the syntax and semantics of Hope, and some techniques for the analysis and design of programs. A main feature of the course is the integration in a natural way of formal methods and reusability with programming.
Machine translation in Europe
Authors: S. Warwick-Armstrong
Venue: Proceedings of the workshop on Speech and Natural Language (1991)

Whereas in the United States work in machine translation (MT) has only recently been reinstated as a 'respectable' natural language processing (NLP) application, it has long been considered a worthwhile and interesting topic for research and development in both Europe and Japan. In terms of number of projects in one sub-field of computational linguistics, MT is currently perhaps the most important application. One obvious reason for this is simply the daily awareness that people communicate in languages other than English, a situation that naturally encourages an interest in translation. On a practical level, for example, every television cable system in Europe broadcasts stations from numerous countries, and on the political level, the European Community (EC) is committed to protecting the language of each of the Member States, which implies providing numerous translation services. From an economic viewpoint, every company knows that in order to market its products, the documentation must be in the language of the target country. And a last motivation for interest in MT, which was also the origin of MT activities in the US and an important concern for Japan, is the desire for better access to information---important documents often exist in some foreign language.
Specification and Design of Transactions in Information Systems: A Formal Approach
Authors: Gilbert Babin, François Lustman, Peretz Shoval
Venue: IEEE Transactions on Software Engineering (1991)

In conventional information systems development, consistency between requirements specifications and design is achieved by manual checking. The application of the transformational paradigm to the specification and design phases is proposed. Requirements are expressed in the ADISSA notation, using the ADISSA method, a transaction-oriented refinement of structured systems analysis. The control part of a transaction is transformed into a formal specification, the FSM (finite state machine) transaction, by applying a set of rules. The design stage is realized by an algorithm which compares the FSM transaction into simpler transactions and implements them with a hierarchical set of finite-state machines. Consistency between the formal specification and the result of the design is achieved by proving that the latter has the same behavior as the former.
A generalized envelope method for sparse factorization by rows
Authors: Joseph W. H. Liu
Venue: ACM Transactions on Mathematical Software (TOMS) (1991)

A generalized form of the envelope method is proposed for the solution of large sparse symmetric and positive definite matrices by rows. The method is demonstated to have practical advantages over the conventional column-oriented factorization using compressed column storage or the multifrontal method using full frontal submatrices.
Dynamic refresh method for dynamic RAMs
Authors: Shogo Matsui
Venue: ACM SIGARCH Computer Architecture News (1992)

DYNAMIC REFRESH METHOD, a new method of refreshing dynamic RAMs is proposed that may result in a significant reduction in the frequency of refresh. The method is based on a fact that a row of the memory cells array in dynamic RAM is normally refreshed whenever a normal access is made. The method is described as a periodic operation with 1/n intervals of the ordinary method. The number of rows refreshed in one cycle varies dynamically. A definition and an implementation of the method are introduced first, the improvement in frequency of refresh is analyzed, and an application example is given.
Computer Networks and Distributed Systems
Authors: Larry D. Wittie
Venue: Computer (1991)

Three major justifications for distributed computing-sharing physically distributed resources, combining computers for fast solutions, and providing reliability through replication-are discussed. Distributed computing milestones from 1969 to 1991 are examined, focusing on the ARPAnet national research network, Ethernet and token-ring local area networks, and workstation networks united by distributed systems software. Three themes that dominate current trends in distributed systems and computer networks are examined. They comprise tapping the immense data-carrying potential of optical fibers, efficiently using tightly coupled networks of thousands of computers, and making network access inexpensive so many people will buy services. Developments for the next decade are predicted by extrapolating from these trends.
Trichromatic approximation for computer graphics illumination models
Authors: Carlos F. Borges
Venue: Proceedings of the 18th annual conference on Computer graphics and interactive techniques (1991)

The complexity of computer graphics illumination models and the associated need to find ways of reducing evaluation time has led to the use of two methods for simplifying the spectral data needed for an exact solution. The first method, where spectral data is sampled at a number of discrete points, has been extensively investigated and bounds for the error are known. Unfortunately, the second method, where spectral data is replaced with tristimulus values (such as RGB values), is very little understood even though it is widely used. In this paper we examine the error incurred by the use of this method by investigating the problem of approximating the tristimulus coordinates of light reflected from a surface from those of the source and the surface. A variation on a well known and widely used approximation is presented. This variation used the XYZ primaries which have unique properties that yield straightforward analytic bounds for the approximation error. This analysis is important because it gives a sound mathematical footing to the widely used method of trichromatic approximation. The error bounds will give some insights into the factors that affect accuracy and will indicate why this method often works quite well in practice.
The arcade laboratory: an environment to help teach algorithms
Authors: J. M. Cagnat, V. Gueraud, J. P. Peyrin
Venue: ACM SIGCSE Bulletin (1990)

We propose different ways to use the computer to help teach algorithms. Our objective however is not to develop a complete and autonomous computer assisted course, such that the student would be given a set of floppy disks and would come back a few months later only for his exams! We want rather to provid e students and teachers with software tools tha t enhance and complement teaching practices as they exist in a traditional environment: formal lectures; exercises in small groups; individual computer assignments.This paper presents elements that guided us during the elaboration of this laboratory: basic ideas, dreams and pedagogical choices. We describe the laboratory as it is today and we try to analyze its potential for students, teachers and software authors. We conclude on possible further developments.
A vacation model for interconnected FDDI networks
Authors: M. Conti, E. Gregori, L. Lenzini
Venue: Proceedings of the 1992 ACM annual conference on Communications (1992)

Metropolitan Area Networks (MANs) have the potential to be interconnected in such a way that the resulting wider, composite network will be still capable of managing integrated services such as video, voice and data. In this paper we develop an analytical tool to explore some aspects of the above environment. In particular, we study two clusters of FDDI subnetworks located in two metropolitan areas communicating through a high bandwidth dedicated link. We define a stochastic model of the above interconnected environment and we derive a closed formula for the probability generating function (PGF) of the distribution of the number of cells in the gateway.
The Art Gallery theorem for polygons with holes
Authors: Frank Hoffmann, Michael Kaufmann, Klaus Kriegel
Venue: Proceedings of the 32nd annual symposium on Foundations of computer science (1991)

Art gallery problems which have been extensively studied over the last decade ask how to station a small (minimum) set of guards in a polygon such that every point of the polygon is watched by at least one guard. The graph-theoretic formulation and solution to the gallery problem for polygons in standard form is given. A complexity analysis is carried out, and open problems are discussed.
A note on Cohen's formal model for computer viruses
Authors: Kimmo Kauranen, Erkki Makinen
Venue: ACM SIGSAC Review (1990)

This note discusses the formal model for computer viruses presented by Fred Cohen. We propose some refinements for the model. Especially, we define a computer virus to be a description of a Turing machine capable of writing a description of another Turing machine to the tape of a universal Turing machine.