ppxscal/embedding_network huggingface dataset:
Practical prefetching via data compression
Authors: Kenneth M. Curewitz, P. Krishnan, Jeffrey Scott Vitter
Venue: Proceedings of the 1993 ACM SIGMOD international conference on Management of data (1993)

An important issue that affects response time performance in current OODB and hypertext systems is the I/O involved in moving objects from slow memory to cache. A promising way to tackle this problem is to use prefetching, in which we predict the user's next page requests and get those pages into cache in the background. Current databases perform limited prefetching using techniques derived from older virtual memory systems. A novel idea of using data compression techniques for prefetching was recently advocated in [KrV, ViK], in which prefetchers based on the Lempel-Ziv data compressor (the UNIX compress command) were shown theoretically to be optimal in the limit. In this paper we analyze the practical aspects of using data compression techniques for prefetching. We adapt three well-known data compressors to get three simple, deterministic, and universal prefetchers. We simulate our prefetchers on sequences of page accesses derived from the OO1 and OO7 benchmarks and from CAD applications, and demonstrate significant reductions in fault-rate. We examine the important issues of cache replacement, size of the data structure used by the prefetcher, and problems arising from bursts of &ldquo;fast&rdquo; page requests (that leave virtually no time between adjacent requests for prefetching and book keeping). We conclude that prediction for prefetching based on data compression techniques holds great promise.
An Introduction to Polar Forms
Authors: Hans-Peter Seidel
Venue: IEEE Computer Graphics and Applications (1993)

Polar forms, which simplify the construction of polynomial and piecewise-polynomial curves and surfaces and lead to new surface representations and algorithms, are reviewed. The polar forms of polynomial curves, Bezier curves, and B-spline are discussed. Tensor product surfaces, the most popular surfaces in computer-aided geometric design, true surfaces, Bezier triangles, B-patches, and a triangular B-spline scheme that combines B-patches and simplex splines are also discussed.
Normalized performance indices for message passing parallel programs
Authors: Sekhar R. Sarukkai, Jerry Yan, Jacob K. Gotwals
Venue: Proceedings of the 8th international conference on Supercomputing (1994)

Existing tools for locating performance bottlenecks of message passing parallel programs either provide visualizations or profiles of program executions only; they do not highlight the cause of poor program performance. From the perspective of the application, the location and cause of performance problems in terms of procedures, processors and data structures are all important. Identifying the cause of poor performance necessitates the need to expose how well the underlying algorithm has been mapped onto the parallel machine. In this paper, we present a suite of normalized performance indices that provide a convenient mechanism for focusing on a location with poor performance. These indices are complemented by additional indices that highlight the cause of the performance failure in terms of processors, procedures and data structure interactions. With the help of examples from the NAS benchmark suite, we show that the automatically generated indices help detect potential causes of poor performance. These indices are generated from execution traces (augmented with data structure information) obtained from monitoring program executions on the Intel iPSC/860.
Viewing morphology as an inference process
Authors: Robert Krovetz
Venue: Proceedings of the 16th annual international ACM SIGIR conference on Research and development in information retrieval (1993)

Morphology is the area of linguistics concerned with the internal structure of words. Information Retrieval has generally not paid much attention to word structure, other than to account for some of the variability in word forms via the use of stemmers. This paper will describe our experiments to determine the importance of morphology, and the effect that it has on performance. We will also describe the role of morphological analysis in word sense disambiguation, and in identifying lexical semantic relationships in a machine-readable dictionary. We will first provide a brief overview of morphological phenomena, and then describe the experiments themselves.
Framework to define CASE tool requirements for distributed environment
Authors: Anil Sharma
Venue: ACM SIGSOFT Software Engineering Notes (1994)

In this paper we develop a framework for requirements definition for a CASE tool which cover all phases of software development life cycle. The resulting requirements are driven through set objectives. Since trend is toward distributed workstation based CASE tools, we would specifically focus on CASE tool requirements for heterogeneous network. These requirement are illustrative and require fine tuning for a specific organisation. But these can be used as a general framework to develop detailed requirement definition. These requirements become the part of general process of evaluating a CASE tool and can be used for example to develop 'Evaluation Check List'. Moreover requirements definitions is not aimed at conceiving a new CASE tool but addresses the issue of what to look for when selecting a CASE tool among many existing.
Computing the Perspective Projection Aspect Graph of Solids of Revolution
Authors: David Eggert, Kevin Bowyer
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1993)

An algorithm for computing the aspect graph for a class of curved-surface objects based on an exact parcellation of 3-D viewpoint space is presented. The object class considered is solids of revolution. A detailed analysis of the visual events for this object class is given, as well as an algorithm for constructing the aspect graph. Numerical search techniques, based on a geometric interpretation of the visual events, have been devised to determine those visual event surfaces that cannot be calculated directly. The worst-case complexity of the number of cells in the parcellation of 3-D viewpoint space, and, hence, the number of nodes in the aspect graph, is O(N/sup 4/), where N is the degree of a polynomial that defines the object shape. A summary of the results for 20 different object descriptions is presented, along with a detailed example for a flower vase.
On a parallel partitioning technique for use with conservative parallel simulation
Authors: Biswajit Nandy, Wayne M. Loucks
Venue: ACM SIGSIM Simulation Digest (1993)

The major goal of this work has been to develop an implementation of a parallel partitioning algorithm which is suitable for use in a conservatively synchronized Parallel Discrete Event Simulation (PDES) environment. Effective partitioning is essential for performance and capacity consideration, for any PDES problem. The performance of the partitioning algorithm is very important, to the overall simulation performance. There are two possible approaches to improve performance for the partitioning step: algorithm modifications; and parallelize the partitioning algorithm (Fiduccia and Mattheyses, 1982) is developed. The basic algorithm has been modified, first for parallel execution with a similar quality of final partition; and then further modified to increase the parallelism of the algorithm, at the expense of partition quality.
Understanding the limitations of causally and totally ordered communication
Authors: David R. Cheriton, Dale Skeen
Venue: ACM SIGOPS Operating Systems Review (1993)

Causally and totally ordered communication support (CATOCS) has been proposed as important to provide as part of the basic building blocks for constructing reliable distributed systems. In this paper, we identify four major limitations to CATOCS, investigate the applicability of CATOCS to several classes of distributed applications in light of these limitations, and the potential impact of these facilities on communication scalability and robustness. From this investigation, we find limited merit and several potential problems in using CATOCS. The fundamental difficulty with the CATOCS is that it attempts to solve problems at the communication level in violation of the well-known "end-to-end" argument.
Parallel processing and trusted database management systems
Authors: Bhavani Thuraisingham, William Ford
Venue: Proceedings of the 1993 ACM conference on Computer science (1993)

This paper applies parallel processing technology to database security technology and vice versa. We first describe the issues involved in incorporating multilevel security into parallel database management systems. In particular, we describe how multilevel security could be incorporated into the GAMMA architecture. Then we describe the use of parallel architectures to perform trusted database management system functions. In particular, we describe security constraint processing in trusted database management systems and show how parallel processing could enhance the performance of this function.
Time-extraction for temporal logic-logic programming and local process time
Authors: Takashi Hattori
Venue: Journal of Computer and System Sciences (1994)

Temporal logic is useful to describe a variety of computer systems such as operating systems and real-time process control systems, where explicit treatment of time plays an essential role. In the logic, the notion of time is represented by a sequence of states at each point in time, which is called a time stream. In distributed environments, it can allow simple descriptions of processes to deal with each process as if it had its own proper time stream where a proper time stream, called an extracted time stream, consists of the events which are essential to the process and are extracted from the original universal time stream. It is proved that, for given formulas which are interpreted in one of the extracted time streams, there exist certain formulas such that they are interpreted in the universal time stream and are equivalent to the given formulas. This time-extraction is applied to the temporal prolog in order to decompose a program into pieces, each of which works in its own time stream. In the same way as logical formulas, a program with time-extraction can be transformed to an equivalent program without time-extraction. It is also proved that the transformations preserve equivalence in the sense of model-theoretic semantics.
Analysis of non-strict functional implementations of the Dongarra-Sorensen eigensolver
Authors: S. Sur, W. Böhm
Venue: Proceedings of the 8th international conference on Supercomputing (1994)

We study the producer-consumer parallelism of Eigensolvers composed of a tridiagonalization function, a tridiagonal solver, and a matrix multiplication, written in the non-strict functional programming language Id. We verify the claim that non-strict functional languages allow the natural exploitation of this type of parallelism, in the framework of realistic numerical codes. We compare the standard top-down Dongarra-Sorensen solver with a new, bottom-up version. We show that this bottom-up implementation is much more space efficient than the top-down version. Also, we compare both versions of the Dongarra-Sorensen solver with the more traditional QL algorithm, and verify that the Dongarra-Sorensen solver is much more efficient, even when run in a serial mode. We show that in a non-strict functional execution model, the Dongarra-Sorensen algorithm can run completely in parallel with the Householder function. Moreover, this can be achieved without any change in the code components. We also indicate how the critical path of the complete Eigensolver can be improved.
Object-oriented geometry and graphics (abstract)
Authors: Jan Krc-Jediny, Augustin Mrazik
Venue: ACM SIGPLAN OOPS Messenger (1993)

Object-Oriented Geometry and Graphics Jan Krc-Jediny Augustin Mrazik, ArtInAppleS, Czechoslovakia Spatial information is an important part of geographic information systems, CAD and CAM systems, and user interfaces for visualization of any kind of information. The object-oriented approach to spatial object modelling results in much more understandable designs than non-object-oriented approaches. This tutorial describes the design of several key components of a system for dealing with spatial information which are: analytical geometry closed with respect to union, intersection and complement operations; hierarchically structured objects for maintaining topological information; object identity and problems arising from change of spatial objects in the database and user interface, transactions and copies of objects; dependencies of spatial objects and their copies in the MVC user-interface architecture. You should have experience in building user-interfaces and should have some background in analytical geometry. Examples are shown in Smalltalk, so a basic knowledge of Smalltalk would be helpful.
A visual execution model for Ada tasking
Authors: Laura K. Dillon
Venue: ACM Transactions on Software Engineering and Methodology (TOSEM) (1993)

A visual execution model for Ada tasking can help programmers attain a deeper understanding of the tasking semantics. It can illustrate subtleties in semantic definitions that are not apparent in natural language design. We describe a contour model of Ada tasking that depicts asynchronous tasks (threads of control), relationships between the environments in which tasks execute, and the manner in which tasks interact. The use of this high-level execution model makes it possible to see what happens during execution of a program. The paper provides an introduction to the contour model of Ada tasking and demonstrates its use.
On reductions of NP sets to sparse sets
Authors: Steven Homer, Luc Longpré
Venue: Journal of Computer and System Sciences (1994)

Ogiwara and Watanabe showed that if SAT is bounded truth-table reducible to a sparse set, then P = NP. In this paper we simplify their proof, strengthen the result and use it to obtain several new results. Among the new results are the following:*Applications of the main theorem to log-truth-table and log-Turing reductions of NP sets to sparse sets. One typical example is that if SAT is log-truth-table reducible to a sparse set then NP is contained in DTIME (2^O^(^l^o^g^^^2^n^)). *Generalizations of the main theorem which yields results similar to the main result at arbitrary levels of the polynomial hierarchy and which extend as well to strong nondeterministic reductions. *The construction of an oracle relative to which P
Analyzing stores and references in a parallel symbolic language
Authors: Suresh Jagannathan, Stephen Weeks
Venue: ACM SIGPLAN Lisp Pointers (1994)

We describe an analysis of a parallel language in which processes communicate via first-class mutable shared locations. The sequential core of the language defines a higher-order strict functional language with list data structures. The parallel extensions permit processes and shared locations to be dynamically created; synchronization among processes occurs exclusively via shared locations.The analysis is defined by an abstract interpretation on this language. The interpretation is efficient and useful, facilitating a number of important optimizations related to synchronization, processor/thread mapping, and storage management.
Three-dimensional alpha shapes
Authors: Herbert Edelsbrunner, Ernst P. Mücke
Venue: ACM Transactions on Graphics (TOG) (1994)

Frequently, data in scientific computing is in its abstract form a finite point set in space, and it is sometimes useful or required to compute what one might call the &ldquo;shape&rdquo; of the set. For that purpose, this article introduces the formal notion of the family of &agr;-shapes of a finite point set in R3. Each shape is a well-defined polytope, derived from the Delaunay triangulation of the point set, with a parameter &agr; &egr; R controlling the desired level of detail. An algorithm is presented that constructs the entire family of shapes for a given set of size n in time 0(n2), worst case. A robust implementation of the algorithm is discussed, and several applications in the area of scientific computing are mentioned.
The computation of eigenvalues and solutions of Mathieu's differential equation for noninteger order
Authors: Randall B. Shirts
Venue: ACM Transactions on Mathematical Software (TOMS) (1993)

Two algorithms for calculating the eigenvalues and solutions of Mathieu's differential equation for noninteger order are described. In the first algorithm, Leeb's method is generalized, expanding the Mathieu equation in Fourier series and diagonalizing the symmetric tridiagonal matrix that results. Numerical testing was used to parameterize the minimum matrix dimension that must be used to achieve accuracy in the eigenvalue of one part in 1012. This method returns a set of eigenvalues below a given order and their associated solutions simultaneously. A second algorithm is presented which uses approximations to the eigenvalues (Taylor series and asymptotic expansions) and then iteratively corrects the approximations using Newton's method until the corrections are less than a given tolerance. A backward recursion of the continued fraction expansion is used. The second algorithm is faster and is optimized to obtain accuracy of one part in 1014, but has only been implemented for orders less than 10.5.
Reflective programming in the relational algebra
Authors: Jan Van den Bussche, Dirk Van Gucht, Gottfried Vossen
Venue: Proceedings of the twelfth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems (1993)

In reflective programming languages it is possible for a program to generate code that is integrated into the program's own execution. We introduce a reflective version of the relational algebra. Reflection is achieved by storing and manipulating relational algebra programs as relations in the database. We then study the expressibility and complexity of the reflective algebra thus obtained. It turns out that there is a close correspondence between reflection and bounded looping. We also discuss the applicability of the reflective algebra.
A case study of domain analysis (abstract): health care
Authors: Martin Fowler, Thomas Cairns
Venue: Addendum to the proceedings on Object-oriented programming systems, languages, and applications (Addendum) (1992)

A Case Study of Domain Analysis: Health Care Martin Fowler Thomas Cairns, St Marys Hospital Medical School , England Three years ago the UK National Health Service decided to develop a generic model to describe all aspects of its management and operation. Several projects were launched to describe the health care process using the object-oriented modeling technique Ptech (now published by James Martin and Jim Odell). One of these projects, the Cosmos project, produced the Cosmos Clinical Process Model (or CCPM), which describes the medical record. The CCPM contains approximately 70 object types in a highly abstract structure describing clinical procedures, observations, evidence and assessment, accountabilities and contracts, care planning, and clinical knowledge. The model has gained widespread interest in both the UK and Europe and will be used as the focus for a number of EEC sponsored projects, and is taking a leading standardization role in Europe. The CCPM is an example of the result of domain analysis. Its use of abstractions, some of which are applicable outside health care, and its use of an operational/knowledge divide can guide those working on large-scale generic models in other areas. The tutorial describes the relationship between generic and specific models since these issues are key in the acceptance of a highly generic application area model by those with specific applications to develop. The question of adapting an object-oriented method for particular needs is also addressed.
Dehn-Sommerville relations, upper bound theorem, and levels in arrangements
Authors: Ketan Mulmuley
Venue: Proceedings of the ninth annual symposium on Computational geometry (1993)

In this note, we generalize the h-vector for simple, bounded convex polytopes [14] to the h-matrix for simple, bounded k-complexes. We observe that the h-matrix is invariant with respect to the defining linear function, and that the Dehn-Sommerville relations and McMullen's Upper Bound Theorem [13] for convex polytopes follow from the invariance ofthe 0-th row and column of this matrix. The invariance of the other entries in the h-matrix should, perhaps, be investigated more. One new consequence is that, given any non-degenerate linear function z, the number of local z-minima on the lth level of any d-dimensional arrangement is bounded by l+d-1d-1 , with exact equality if the l-th level is bounded and simple.
Differences between public and private management information systems
Authors: Ronald R. Gauch
Venue: Proceedings of the 1993 conference on Computer personnel research (1993)

A survey was taken among MIS managers responsible for systems development, to determine if differences between private and public organizations reported in the literature existed. The results suggest that 1] the negative image of the public sector as an employer, compared to private industry, is not as intense as the literature suggests, 2] sector differences become more prevalent for MIS managers as they move up the organizational hierarchy and 3] public MIS managers are facing a greater threat to the control of computerized information systems. The implications of these findings on the recruitment and retention of MIS personnel are discussed.
Dynamic Perfect Hashing: Upper and Lower Bounds
Authors: Martin Dietzfelbinger, Anna Karlin, Kurt Mehlhorn, Friedhelm Meyer auf der Heide, Hans Rohnert, Robert E. Tarjan
Venue: SIAM Journal on Computing (1994)

The dynamic dictionary problem is considered: provide an algorithm for storing a dynamic set, allowing the operations insert, delete, and lookup. A dynamic perfect hashing strategy is given: a randomized algorithm for the dynamic dictionary problem that takes $O(1)$ worst-case time for lookups and $O(1)$ amortized expected time for insertions and deletions; it uses space proportional to the size of the set stored. Furthermore, lower bounds for the time complexity of a class of deterministic algorithms for the dictionary problem are proved. This class encompasses realistic hashing-based schemes that use linear space. Such algorithms have amortized worst-case time complexity $\Omega(\log n)$ for a sequence of $n$ insertions and lookups; if the worst-case lookup time is restricted to $k$, then the lower bound becomes $\Omega(k\cdot n^{1/k})$.
Efficient flow-sensitive interprocedural computation of pointer-induced aliases and side effects
Authors: Jong-Deok Choi, Michael Burke, Paul Carini
Venue: Proceedings of the 20th ACM SIGPLAN-SIGACT symposium on Principles of programming languages (1993)

We present practical approximation methods for computing interprocedural aliases and side effects for a program written in a language that includes pointers, reference parameters and recursion. We present the following results: 1) An algorithm for flow-sensitive interprocedural alias analysis which is more precise and efficient than the best interprocedural method known. 2) An extension of traditional flow-insensitive alias analysis which accommodates pointers and provides a framework for a family of algorithms which trade off precision for efficiency. 3) An algorithm which correctly computes side effects in the presence of pointers. Pointers cannot be correctly handled by conventional methods for side effect analysis. 4) An alias naming technique which handles dynamically allocated objects and guarantees the correctness of data-flow analysis. 5) A compact representation based on transitive reduction which does not result in a loss of precision and improves precision in some case. 6) A method for intraprocedural alias analysis which is based on a sparse representation.