ppxscal/embedding_network huggingface dataset:
Generic virtual memory management for operating system kernels
Authors: E. Abrossimov, M. Rozier, M. Shapiro
Venue: Proceedings of the twelfth ACM symposium on Operating systems principles (1989)

We discuss the rationale and design of a Generic Memory management Interface, for a family of scalable operating systems. It consists of a general interface for managing virtual memory, independently of the underlying hardware architecture (e.g. paged versus segmented memory), and independently of the operating system kernel in which it is to be integrated. In particular, this interface provides abstractions for support of a single, consistent cache for both mapped objects and explicit I/O, and control of data caching in real memory. Data management policies are delegated to external managers. A portable implementation of the Generic Memory management Interface for paged architectures, the Paged Virtual Memory manager, is detailed. The PVM uses the novel history object technique for efficient deferred copying. The GMI is used by the Chorus Nucleus, in particular to support a distributed version of Unix. Performance measurements compare favorably with other systems.
A Hitherto Unnoticed Singularity of Scale-Space
Authors: J. J. Koenderink
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1989)

A hitherto unnoticed singularity of scale space occurs only at isolated points in scale space. Thus it does not generically occur for single images, but it can occur occasionally in members of time sequences (say). It occurs at those critical points of the image at which the Laplacean of the illuminance vanishes (a nongeneric condition). The structure of scale space in an infinitesimal neighborhood of such a singularity is explored. The effect of the singularity of mappings between copies of an image at different levels of resolution is evaluated and checked with a numerical calculation.
Optimal allocation of multiple class resources in computer systems
Authors: A. N. Tantawi, G. Towsley, J. Wolf
Venue: ACM SIGMETRICS Performance Evaluation Review (1988)

A class-constrained resource allocation problem is considered. In this problem, a set of M heterogeneous resources is to be allocated optimally among a set of L users belonging to K user classes. A set of class allocation constraints, which limit the number of users of a given class that could be allocated to a given resource, is imposed. An algorithm with worst case time complexity O(M (LM + M2 + LK)) is presented along with a proof of its correctness. This problem arises in many areas of resource management in computer systems, such as load balancing in distributed systems, transaction processing in distributed database systems, and session allocation in time-shared computer systems. We illustrate the behavior of this algorithm with an example where file servers are to be allocated to workstations of multiple classes.
Type systems for querying class hierarchies with non-strict inheritance
Authors: A. Borgida
Venue: Proceedings of the eighth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems (1989)

Type checking at query compilation time is important for both detecting programmer errors and reducing the running time of queries. We have argued elsewhere [2] that entity-based data management systems which support class hierarchies, such as semantic data models and object-oriented dbms, should not be confined to have &ldquo;strict inheritance&rdquo; &mdash; i.e., they should permit contradictions between class specifications, albeit in an explicit and controlled way. In this paper we present a type system for queries manipulating objects in such classes. We provide sound and complete axiomatizations of the predications &ldquo;&sgr; is a subtype of &tgr;&rdquo; and &ldquo;expression e has type &tgr;&rdquo;. The absence of strict inheritance has normally been felt to preclude effective type checking. We show that the problem is co-NP-hard when disjoint types are admitted in the schema, but present a low-order polynomial-time algorithm that determines the absence of type errors in a query when the database has only entities.
Small sets supporting fary embeddings of planar graphs
Authors: Hubert de Fraysseix, János Pach, Richard Pollack
Venue: Proceedings of the twentieth annual ACM symposium on Theory of computing (1988)

Answering a question of Rosenstiehl and Tarjan, we show that every plane graph with n vertices has a F&aacute;ry embedding (i.e., straight-line embedding) on the 2n - 4 by n - 2 grid and provide an &Ogr;(n) space, &Ogr;(n log n) time algorithm to effect this embedding. The grid size is asymptotically optimal and it had been previously unknown whether one can always find a polynomial sized grid to support such an embedding. On the other hand we show that any set F, which can support a F&aacute;ry embedding of every planar graph of size n, has cardinality at least n + (1 - &ogr;(1)) &radic;n which settles a problem of Mohar.
Efficient evaluation of right-, left-, and multi-linear rules
Authors: J. F. Naughton, R. Ramakrishnan, Y. Sagiv, J. D. Ullman
Venue: ACM SIGMOD Record (1989)

We present an algorithm for the efficient evaluation of a useful subset of recursive queries. Like the magic sets transformation, the algorithm consists of a rewriting phase followed by semi-naive bottom-up evaluation of the resulting rules. We prove that on a wide range of recursions, this algorithm achieves a factor of &Ogr;(n) speedup over magic sets. Intuitively, the transformations in this algorithm achieve their performance by reducing the arity of the recursive predicates in the transformed rules.
Pose Determination of a Three-Dimensional Object Using Triangle Pairs
Authors: S. Linnainmaa, D. Harwood, L. S. Davis
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1988)

A procedure is presented to estimate the unconstrained three-dimensional location and orientation of an object with a known shape when it is visible in a single image. Using a generalized Hough transform, all six parameters of the object position are estimated from the distribution of values determined by matching triples of points on the object to possibly corresponding triples in the image. Most likely candidates for location are found, and then the remaining rotational parameters are evaluated. Two solutions are generally admitted to the distribution by every match of triangles. The number of possible matches is reduced by checking a simple geometric relation among triples. Even with partial occlusion, experiments indicate that the procedure is very reliably accurate, although optimization can further improve estimates of the parameters.
Constructing Specifications by Combining Parallel Elaborations
Authors: Martin S. Feather
Venue: IEEE Transactions on Software Engineering (1989)

An incremental approach to construction is proposed, with the virtue of offering considerable opportunity for mechanized support. Following this approach one builds a specification through a series of elaborations that incrementally adjust a simple initial specification. Elaborations perform both refinements, adding further detail, and adaptations, retracting oversimplifications and tailoring approximations to the specifics of the task. It is anticipated that the vast majority of elaborations can be concisely described to a mechanism that will then perform them automatically. When elaborations are independent, they can be applied in parallel, leading to diverging specifications that must later be recombined. The approach is intended to facilitate comprehension and maintenance of specifications, as well as their initial construction.
CLP and constraint abstraction
Authors: T. J. Hickey
Venue: Proceedings of the 16th ACM SIGPLAN-SIGACT symposium on Principles of programming languages (1989)

CLP*(D) is a class of constraint logic programming languages which incorporates the notion of abstraction. Predicates in CLP*(D) are (potentially) infinite rational trees which represent abstractions of constraint expressions. This view of predicates as constraint abstractions was motivated by the language Scheme, where closures are viewed as abstractions of functional expressions. A semantics and an efficient implementation of the language are provided, along with several examples of the novel programming techniques provided by this class of languages.
On the VLSI Design of a Pipeline Reed-Solomon Decoder Using Systolic Arrays
Authors: H. M. Shao, I. S. Reed
Venue: IEEE Transactions on Computers (1988)

A novel VLSI design for a pipeline Reed-Solomon decoder is presented. The transform decoding technique used in a previous study is replaced by a time-domain algorithm through a detailed comparison of their VLSI implementations. An architecture that implements the time-domain algorithm permits efficient pipeline processing with reduced circuitry. Erasure correction capability is also incorporated with little additional complexity. By using multiplexing technique, an implementation of Euclid's algorithm maintains the throughput rate with less circuitry. Some improvements result in both enhanced capability and significant reduction in silicon area, making it possible to build the decoder on a single chip.
Teaching multiple programming paradigms: a proposal for a paradigm general pseudocode
Authors: M. B. Wells, B. L. Kurtz
Venue: ACM SIGCSE Bulletin (1989)

Initial overexposure to the imperative programming paradigm can make it very difficult to introduce students to other paradigms, such as the functional, object oriented and logical paradigms. It is important that students be exposed to several programming paradigms early. Two techniques commonly used to accomplish this are a &ldquo;survey of languages&rdquo; approach and use of a language, such as Scheme, that overlaps several paradigms. We propose the use of a paradigm-general pseudocode that can then be translated into the most appropriate target language. This paper describes in detail the features and form of this pseudocode using familiar algorithms. This approach has been used successfully in an upper division class and we believe it can be refined and introduced earlier in the curriculum.
The use of modelling in long-range computer communications network planning
Authors: R. K. Leighton
Venue: Proceedings of the 21st conference on Winter simulation (1989)

There has been an incredible expansion and proliferation of computer communications networks in the last 10 years, most of them proprietary. Furthermore, the use of these networks has changed from a business operations tool to a strategic weapon for corporations. In order to better coordinate and control the growth of these networks, as well as add functionality, communications architecture plans are being developed for the corporate networks of the nineties. Cost/benefits analyses of these architectures have to be played against the proposed strategic plans of the corporation. Also, it is desirable to test these architectures for a number of scenarios involving future variations of regulatory, technology and standards projections that vitally effect the networks. All of this analysis is aggravated considerably by a lack of operations data for the current networks along with incomplete data on future computer communications protocols, services and loads.The purpose of this paper is to present a methodology involving modelling on several levels that will not only quickly present very high-level, cost-benefit analyses for proposed architectures, but will continue to refine these analyses as all future data gathering and modelling work is prioritized and refined on an ongoing basis. The result will be an up-to-date repository for all communications planning tools and data.
The computer background of incoming freshman: looking for emerging trends
Authors: Jan L. Harrington
Venue: ACM SIGCSE Bulletin (1988)

As part of a longitudinal study begun in 1985, incoming Bentley College freshmen were asked to complete questionnaires about their pre-college computer experience. Although nearly all students came from high schools with computers and more than 80% of them had studied BASIC, just under half had used a word processor. Even fewer (less than 20%) had used either a spreadsheet or a database management system, though the actual percentage has risen over the three years for which data exist. The increase in the number of schools teaching Pascal noticed between 1984 and 1985 persisted in 1986. However, though nearly 46% of the schools from which 1986 graduates came taught Pascal, only half that percentage actually studied the language. Almost half the students used computers outside school during their high school years, but most of that use involved playing games.
Computing intersections and normalizersin soluble groups
Authors: S. P. Glasby, Michael C. Slattery
Venue: Journal of Symbolic Computation (1990)

Let H and K be arbitrary subgroups of a finite soluble group G. The purpose of this paper is todescribe algorithms for constructing H@?K and N"G(H). The first author has previously described algorithms for constructing H@?K when the indices |G:H| and |G:K| are coprime, and for constructing N"G(H) when |G:H| and |H| are coprime (i.e. when H is a Hall subgroup of G). The intersection and normalizer algorithms described in the present paper are constructed from generalizations of these algorithms and from an orbit-stabilizer algorithm.
Dynamic bandwidth management of primary rate ISDN to support ATM access
Authors: B. R. Harita, I. M. Leslie
Venue: ACM SIGCOMM Computer Communication Review (1989)

One of the principle advantages of Asynchronous Transfer Mode (ATM) access is that variable rate streams can be supported efficiently. In order to preserve this efficiency when using ATM on an underlying circuit switched network, such as primary rate ISDN, flexible control of the underlying circuit bandwidth must be provided. This paper discusses techniques used to provide dynamic management of variable rate circuits to support ATM access. Models are presented for some of these control schemes and their performance is studied through a combination of simulation and analysis. Techniques implemented for an experimental network providing ATM access on primary rate ISDN are presented.
The derivation problem of summary data
Authors: F. M. Malvestuto
Venue: Proceedings of the 1988 ACM SIGMOD international conference on Management of data (1988)

Given a statistical database consisting of two summary tables based on a common but not identical classification criterion (e.g., two geographical partitionings of a country) there are additional summary tables that are derivable in the sense that they are uniquely (i.e., with no uncertainty) determined by the tables given. Derivable tables encompass not only, of course, &ldquo;less detailed&rdquo; tables (that is, aggregated data) but also &ldquo;more detailed&rdquo; tables (that is, disaggregated data). Tables of the second type can be explicitly constructed by using a &ldquo;procedure of data refinement&rdquo; based on the graph representation of the correspondences between the categories of the two classification systems given in some cases, that is, when such a graph representation meets the acyclicity condition, the underlying database is &ldquo;equivalent&rdquo; to a single table (called representative table) and then a necessary and sufficient condition for a table to be derivable can be stated.
Parallel placement of parallel processes
Authors: C. C. Pettey, M. R. Leuze
Venue: Proceedings of the third conference on Hypercube concurrent computers and applications: Architecture, software, computer systems, and general issues - Volume 1 (1988)

The problem of placing the individual processes of a logically partitioned problem on the nodes of a multiprocessor in such a manner as to minimize the communication and memory utilization costs is known as the process placement problem. This problem is, in general, NP-complete. A number of algorithms for finding approximate solutions to the process placement problem have been investigated. Some of these algorithms rely on heuristics to initially place the processes. This approach is sometimes followed by iterative refinement, where pairs of processes are swapped in a search for better approximations. For other algorithms which rely almost solely on iterative refinement, initial placement is of much less importance. Recently simulated annealing, a more sophisticated adaptive search technique, has been applied to the process placement problem. All of these process placement algorithms are sequential. (Although simulated annealing has recently been implemented in parallel on a hypercube architecture, no work has been done in applying the parallel version to the process placement problem.) The purpose of this paper is to discuss work with a parallel algorithm for approximating solutions to the process placement problem. The algorithm has been implemented on an Intel iPSC hypercube with 16 nodes. The class of problems which were investigated involve mapping logical problem graphs to physical architectural interconnection graphs (e.g., mapping a binary tree to a hypercube or mapping a hypercube to a hypercube). The algorithm (PGA) is a parallel version of genetic algorithms, an adaptive search technique based on the principles of population genetics. Unlike the previously mentioned algorithms, PGA can be implemented on the multiprocessor system to which the actual logical problem will be mapped.
The AdaPIC Tool Set: Supporting Interface Control and Analysis Throughout the Software Development Process
Authors: Alexander L. Wolf, Lori A. Clarke, Jack C. Wileden
Venue: IEEE Transactions on Software Engineering (1989)

The AdaPIC tool set, an important component of an Ada software development environment, is discussed. The AdaPIC tool set is one particular instantiation, specifically adapted for use with Ada, of the more general collection of language features and analysis capabilities that constitute the PIC approach to describing and analyzing relationships among software system components. This tool set is being tailored to support an incremental approach to the interface control aspects of the software development process. Following a discussion of the PIC interface control and incremental development concepts, the AdaPIC tool set is described, concentrating on its analysis tools and support for incremental development and demonstrating how it contributes to the technology for developing large Ada software systems.
Object-oriented design: a responsibility-driven approach
Authors: R. Wirfs-Brock, B. Wilkerson
Venue: Conference proceedings on Object-oriented programming systems, languages and applications (1989)

Object-oriented programming languages support encapsulation, thereby improving the ability of software to be reused, refined, tested, maintained, and extended. The full benefit of this support can only be realized if encapsulation is maximized during the design process. We argue that design practices which take a data-driven approach fail to maximize encapsulation because they focus too quickly on the implementation of objects. We propose an alternative object-oriented design method which takes a responsibility-driven approach. We show how such an approach can increase the encapsulation by deferring implementation issues until a later stage.
Knowledge and common knowledge in a distributed environment
Authors: Joseph Y. Halpern, Yoram Moses
Venue: Journal of the ACM (JACM) (1990)

Reasoning about knowledge seems to play a fundamental role in distributed systems. Indeed, such reasoning is a central part of the informal intuitive arguments used in the design of distributed protocols. Communication in a distributed system can be viewed as the act of transforming the system's state of knowledge. This paper presents a general framework for formalizing and reasoning about knowledge in distributed systems. It is shown that states of knowledge of groups of processors are useful concepts for the design and analysis of distributed protocols. In particular, distributed knowledge corresponds to knowledge that is &ldquo;distributed&rdquo; among the members of the group, while common knowledge corresponds to a fact being &ldquo;publicly known.&rdquo; The relationship between common knowledge and a variety of desirable actions in a distributed system is illustrated. Furthermore, it is shown that, formally speaking, in practical systems common knowledge cannot be attained. A number of weaker variants of common knowledge that are attainable in many cases of interest are introduced and investigated.
A network environment for computer-supported cooperative work
Authors: J. Whitescarver, P. Mukherji, M. Turoff, R. J. DeBlock,  Jr., R. M. Czech, B. K. Paul
Venue: ACM SIGCOMM Computer Communication Review (1987)

A second generation computer supported cooperative work system called Electronic Information Exchange System (EIES2) is described in this paper. The EIES2 communications environment allows users to network across geographical constraints using asynchronous or synchronous communications. The architecture of the network environment is decentralized, and is implemented using modern standards, and an easy-to-use user interface. At the heart of EIES2 is a high-level, object oriented pseudo machine which incorporates a distributed, communications-oriented database. The set of tools provided by the EIES2 communications environment is well suited for implementing group communication systems that have an extensive set of user features built into it. These tools are well suited to support the group communication model described by the AMIGO task force (IFIP 6.5 and ISO TC97/SC18/WG64). The EIES2 application layer protocols, using CCITT/ISO X.410 Remote Operations, support a distributed object oriented database.
Graphics techniques in concurrent simulation
Authors: V. Warren
Venue: Proceedings of the third conference on Hypercube concurrent computers and applications: Architecture, software, computer systems, and general issues - Volume 1 (1988)

This paper discusses work occurring in the hypercube simulation laboratory and visualization schemes for concurrent simulation. The principle contribution of this work is that of a cost effective technical approach to simulation visualization. This approach is being replicated and applied to contemporary large scale simulation problems of interest around the country. Since the hypercube graphics interface is a working prototype there is a mix of practice and experience along with novel approaches to contemporary graphics problems. A discussion of techniques which accelerated graphics development is included. Among these are issues of interpreted vs. compiled tools for simulation visualization and supercomputer-display interface methodology. A survey of other significant efforts in combining hypercubes and graphics is provided. Finally the issue of interactive simulation exploration via real time displays is discussed with an eye toward the future.