ppxscal/embedding_network huggingface dataset:
Combinatorial complexity of translating a box in polyhedral 3-space
Authors: Dan Halperin, Chee-Keng Yap
Venue: Proceedings of the ninth annual symposium on Computational geometry (1993)

We study the space of free translations of a box amidst polyhedral obstacles with n features. We show that the combinatorial complexity of this space is O(n2&agr;(n)) where &agr;(n) is the inverse Ackermann function. Our bound is within an &agr;(n) factor off the lower bound, and it constitutes an improvement of almost an order of magnitude over the best previously known (and naive) bound for this problem, O(n3).
The role of a natural language interface in diffusing computer assisted journalism: an empirical investigation
Authors: Linda Roberge
Venue: Proceedings of the 1993 conference on Computer personnel research (1993)

Based on innovation diffusion theory, an individual's decision to adopt an innovation is related to how the individual in question perceives the innovation. Of concern to this study is whether or not a natural language interface can modify how the characteristics of a technological innovation are perceived. This issue will be examined by exploring the impact of a natural language interface on individual perceptions of computer assisted journalism.
Structured interrupts
Authors: Ted Hills
Venue: ACM SIGOPS Operating Systems Review (1993)

In this paper I refine the concept of interrupt to define a more structured mechanism with straightforward semantics. Some commonly implemented interrupt mechanisms are reviewed; their semantics are deduced and analyzed. I show how a different understanding of interrupts resolves the deficiencies of existing interrupt mechanisms and provides the programmer with powerful tools for addressing real-time and multiprocessing problems. On this basis a recommendation is made for architectural and operating system support of the improved interrupt mechanism.
Generating local addresses and communication sets for data-parallel programs
Authors: Siddhartha Chatterjee, John R. Gilbert, Fred J. E. Long, Robert Schreiber, Shang-Hua Teng
Venue: ACM SIGPLAN Notices (1993)

Generating local addresses and communication sets is an important issue in distributed-memory implementations of data-parallel languages such as High Performance Fortran. We show that for an array A affinely aligned to a template that is distributed across p processors with a cyclic(k) distribution, and a computation involving the regular section A(l:h:s), the local memory access sequence for any processor is characterized by a finite state machine of at most k states. We present fast algorithms for computing the essential information about these state machines, and extend the framework to handle multidimensional arrays. We also show how to generate communication sets using the state machine approach. Performance results show that this solution requires very little runtime overhead and acceptable preprocessing time.
Finding level-ancestors in trees
Authors: Omer Berkman Uzi Vishkin
Venue: Journal of Computer and System Sciences (1994)

The level-ancestor problem is considered. Suppose a rooted tree T is given for preprocessing. Answer quickly queries of the following form. Given a vertex v and an integer i > 0, find the ith vertex on the path from v to the root. Given any m, 1 @? m @? log*n, we achieve the following results: (1) O(log^(^m^)n) time using an optimal number of processors for preprocessing and constant time using a single processor for processing a query if m is constant. (2) O(log* n) time using an optimal number of processors for preprocessing and O(log* n) time using a single processor for processing a query. These results assume that the Euler tour of the tree and the level (distance from the root) of each vertex are given. Without these assumptions, the only change in result (1) above is that preprocessing time increases to O(log n). An immediate corollary is a serial linear-time bound for preprocessing and a constant-time bound for processing a query.
Protocol service decomposition for high-performance networking
Authors: Chris Maeda, Brian N. Bershad
Venue: Proceedings of the fourteenth ACM symposium on Operating systems principles (1994)

In this paper we describe a new approach to implementing network protocols that enables them to have high performance and high flexibility, while retaining complete conformity to existing application programming interfaces. The key insight behind our work is that an application's interface to the network is distinct and separable from its interface to the operating system. We have separated these interfaces for two protocol implementations, TCP/IP and UDP/IP, running on the Mach 3.0 operating system and UNIX server. Specifically, library code in the application's address space implements the network protocols and transfers data to and from the network, while an operating system server manages the heavyweight abstractions that applications use when manipulating the network through operations other than send and receive. On DECstation 5000/200 systems connected by 10Mb/sec Ethernet, this approach to protocol decomposition achieves TCP/IP throughput of 1088 KB/second, which is comparable to that of a high-quality in-kernel TCP/IP implementation, and substantially better than a server-based one. Our approach achieves small-packet UDP/IP round trip latencies of 1.23 ms, again comparable to a kernel-based implementation and more than twice as fast as a server-based one.
Agentsheets: a tool for building domain-oriented visual programming environments
Authors: Alex Repenning
Venue: Proceedings of the INTERACT '93 and CHI '93 conference on Human factors in computing systems (1993)

Visual programming systems are supposed to simplify programming by capitalizing on innate human spatial reasoning skills. I argue that: (i) good visual programming environments should be oriented toward their application domains, and (ii) tools to build domain-oriented environments are needed because building such environments from scratch is very difficult. The demonstration illustrates how the visual programming system builder called Agentsheets addresses these issues and demonstrates several applications built using Agentsheets.
Conceptual modelling in the hypermedia development process
Authors: Jana Dospisil, Tony Polgar
Venue: Proceedings of the 1994 computer personnel research conference on Reinventing IS : managing information technology in changing organizations: managing information technology in changing organizations (1994)

This paper explores the potential of using multiple software requirements specification methods for elicitation of concepts in the development of university courseware based on the multimedia and hypermedia technology. At universities, the use of hypermedia and multimedia technology is perceived as one of the most efficient ways to enhance student access to information and improve learning interaction in the undergraduate computer science course. Such an approach will guarantee high level quality teaching whilst permitting significant reduction in lecturer-student contact hours. The process which plays the critical role in such a development environment is the concepts acquisition and requirements specification, collectively called requirements engineering.The hypermedia design and programming development process shows some peculiarities which make them different from the &ldquo;classic&rdquo; development activities. The main areas of interest include the user requirements engineering and removing ambiguity of natural language from software requirements specifications. There is a need to devise an integrated set of specification notations which would cater for the irregularities introduced by the differences in media while supporting commonly used development activities.In this case study, we assume a typical interactive multimedia development process in a teaching environment. The objective is to assess the role of prototyping and to establish the main characteristics of the formal requirements specification notation(s) as a means for achieving a more efficient utilisation of complex computing technologies. The horizontal design partitioning concept is used to establish clear demarcation lines between the development process phases. The vertical design partitioning is used to reduce complexity of the design by enforcing predictable structural patterns and presentation logic components. This approach allows deployment of the multiple specification notations in the design and implementation process.The paper is organized as follows: Firstly, we discuss the key characteristics of the hypermedia design process. In section two, the role of prototyping is critically evaluated. Section three provides our view of concepts acquisition and requirements management process. Remaining sections of this case study depict our proposed conceptual model for hypermedia based courseware development process.
Fast Triangular Factorization and Inversion of Hankel and Related Matriceswith Arbitrary Rank Profile
Authors: Debajyoti Pal, Thomas Kailath
Venue: SIAM Journal on Matrix Analysis and Applications (1994)

The authors present a fast procedure for computing a "modified" triangular factorization of Hankel, quasi-Hankel (matrices congruent in a certain sense to Hankel matrices) and sign-modified quasi-Hankel (products of quasi-Hankel and signature matrices) matrices. A fast procedure for computing inverse of Hankel and quasi-Hankel matrices is also presented. A modified triangular factorization is an $LDL*$ factorization, where $L$ is lower triangular with unit diagonal entries and $D$ is a block diagonal matrix with possibly varying block sizes. Only matrices with all leading minors nonzero, often called strongly regular, will always have a purely diagonal and nonsingular $D$ matrix. The matrices studied in this paper have diagonal blocks with a particular Hankel-(like) structure. The algorithms presented here are obtained by extending a generating function approach of Lev-Ari and Kailath for matrices with a generalized displacement structure. A particular application of the results is a fast method of computing the rank profile and inertia of the matrices involved.
Two-Arc Transitive Graphs and Twisted Wreath Products
Authors: Robert W. Baddeley
Venue: Journal of Algebraic Combinatorics: An International Journal (1993)

The paper addresses a part of the problem of classifying all 2-arc transitive graphs: namely, that of finding all groups acting 2-arc transitively on finite connected graphs such that there exists a minimal normal subgroup that is nonabelian and regular on vertices. A construction is given for such groups, together with the associated graphs, in terms of the following ingredients: a nonabelian simple group T, a permutation group P acting 2-transitively on a set &Omega;, and a map F : &Omega;&rarr;Tsuch that x &equals; x&minus;1 for all x &isin; F(&Omega;) and such that Tis generated by F(&Omega;). Conversely we show that all such groups and graphs arise in this way. Necessary and sufficient conditions are found for the construction to yield groups that are permutation equivalent in their action on the vertices of the associated graphs (which are consequently isomorphic). The different types of groups arising are discussed and various examples given.
Usability measurement: its practical value to the computer industry
Authors: M. Maguire, A. Dillon
Venue: Proceedings of the INTERACT '93 and CHI '93 conference on Human factors in computing systems (1993)

This panel will consider the role of usability measurement in the design process. It will address the time needed to perform usability evaluations and compare this process with that of expert assessment. This topic will be discussed in the industrial context of developing computer products within strict timescales. However it will also be seen against the traditional problem of needing to set usability goals and to measure their achievement if usability is to be given the same priority as the more technical software engineering objectives.
Sign language interfaces
Authors: Nancy Frishberg, Serena Corazza, Linda Day, Sherman Wilcox, Rolf Schulmeister
Venue: Proceedings of the INTERACT '93 and CHI '93 conference on Human factors in computing systems (1993)

This panel will start to build the bridge between behavioral scientists who know deaf communities worldwide, their languages and cultures, and experts in technical disciplines relating to computers and human interfaces.
Construction of Graded Covariant GL(m/n) Modules Using Tableaux
Authors: R. C. King, T. A. Welsh
Venue: Journal of Algebraic Combinatorics: An International Journal (1992)

Irreducible covariant tensor modules for the Lie supergroups GL(m/n) and the Lie superalgebras gl(m/n) and sl(m/n) are obtained through the use of Young tableaux techniques. The starting point is the graded permutation action, first introduced by Dondi and Jarvis, on V&otimes;l. The isomorphism between this group of actions and the symmetric group Sl enables the graded generalization of the Young symmetrizers, and hence of the column relations and Garnir relations, to be made. Consequently, corresponding to each partition of l an irreducible GL(m/n) module may be obtained as a submodule of V&otimes;l. A basis for the module labeled by the partition &lambda; is provided by GL(m/n)&ndash;standard tableaux of shape &lambda; defined by Berele and Regev. The reduction of an arbitrary tableau to standard form is accomplished through the use of graded column relations and graded Garnir relations. The standardization procedure is algorithmic and allows matrix representations of the Lie superalgebras gl(m/n) and sl(m/n) to be constructed explicitly over the field of rational numbers. All the various steps of the standardization algorithm are exemplified, as well as the explicit construction of matrices representing particular elements of gl(m/n) and sl(m/n).
A general framework for semantics-based bottom-up abstract interpretation of logic programs
Authors: Roberto Barbuti, Roberto Giacobazzi, Giorgio Levi
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1993)

The theory of abstract interpretation provides a formal framework to develop advanced dataflow analysis tools. The idea is to define a nonstandard semantics which is able to compute, in finite time, an approximated model of the program. In this paper, we define an abstract interpretation framework based on a fixpoint approach to the semantics. This leads to the definition, by means of a suitable set of operators, of an abstract fixpoint characterization of a model associated with the program. Thus, we obtain a specializable abstract framework for bottom-up abstract interpretations of definite logic programs. The specialization of the framework is shown on two examples, namely, gound-dependence analysis and depth-k analysis.
A first course in computer science for small four year CS programs
Authors: Robert Bryant, Paul De Palma
Venue: ACM SIGCSE Bulletin (1993)

The paper is a contribution to the ongoing debate over the content of CS1. Instead of opting for either the depth first or breadth-first approach, we have built a course using some of the strongest elements of each. This course does not replace CS1 in our department. Rather, we use it to give beginning computer science students a more balanced view of the discipline than CS1 does. We also use it to teach in one place much of the redundant material found in the standard computer science curriculum. We find this makes for more sophisticated students and lets us use our small faculty more efficiently.
Necessity is the mother of language features
Authors: Jacobo Carrasquel
Venue: ACM SIGCSE Bulletin (1993)

A common problem when teaching CS1 courses to non-CS majors is students' lack of motivation. This paper describes a new approach and methodology intended to solve this problem: The new approach involves a different sequencing of topics covered in most CS1 courses, and the division of the course into four units; thus exposing students to four different problems of moderate length and degree of difficulty. The new methodology consists of presenting students with problems for which the programming features learned up to that point are inadequate to solve the task. Thus, instead of presenting topics (language features) followed by a series of problems which require the student to apply specific tools, I introduce problems which create a need for new language features. This way students feel more motivated to explore new venues and participate more effectively in the decision-making process.
Using static single assignment form in a code optimizer
Authors: Carl McConnell, Ralph E. Johnson
Venue: ACM Letters on Programming Languages and Systems (LOPLAS) (1992)

Static single assignment form represents data dependences elegantly and provides a basis for powerful optimizations. Table-driven techniques for peephole optimization and code generation are straightforward and effective. it is natural to want to use both together in a code optimizer. However, doing so reveals that static single assignment form does not remove all antidependences, and that it conflicts with table-driven code generation for 2-address machines. This paper describes these problems and how to solve them.
A general, fine-grained, machine independent, object-oriented language
Authors: Birger Andersen
Venue: ACM SIGPLAN Notices (1994)

This paper introduces the general-purpose object-oriented programming language Ellie which supports machine independent fine-grained objects and parallelism. As something particular, classes, types, blocks, and methods are abstracted by first class objects/citizens called Ellie objects. Ellie demonstrates new approaches for abstraction and code reuse in parallel programming.The goals of Ellie have been to obtain an extremely flexible, machine independent, parallel language. Ellie tries to meet these goals by extensive usage of selected language concepts combined with compile-time analysis to adapt programs for efficient execution on the available hardware. Ellie runs on a parallel mesh transputer network.
Cluster analysis and workload classification
Authors: Kimmo E. E. Raatikainen
Venue: ACM SIGMETRICS Performance Evaluation Review (1993)

Clustering techniques are widely recommended tools for workload classification. The k-means algorithm is widely accepted as the "standard" technique of detecting workload classes automatically from measurement data. This paper examines validity of the obtained workload classes, when the current system and workload is analyzed by a queueing network model and mean value analysis. Our results, based on one week's accounting data of a VAX 8600, indicate that the results of queueing network analysis are not stable when the classes of workload are constructed through the k-means algorithm. Therefore, we cannot recommended that the most widely used clustering technique should be used in any workload characterization study without careful validation.
The Cost of Broadcasting on Star Graphs and k-ary Hypercubes
Authors: Sidney W. Graham, Steven R. Seidel
Venue: IEEE Transactions on Computers (1993)

It is shown that for two common broadcasting problems, a star graph performs better than a k-ary hypercube with a comparable number of nodes only in networks consisting of an impractically large numbers of nodes. This result is based on a comparison of the costs of known solutions to the one-to-all broadcast and the complete broadcast problems for each network. It is suggested that the cost of solutions to these common problems is a better indication of the expected performance of an interconnection network than is a comparison of scalar measures such as the diameter and degree.
Determining initial states for time-parallel simulations
Authors: Jain J. Wang, Marc Abrams
Venue: ACM SIGSIM Simulation Digest (1993)

Time-parallel simulations exploit parallelism by partitioning the time domain of a simulation model. Exploiting temporal parallelism requires predicting future states of a simulation model. A poor prediction of future states may cause extensive recomputation so that a time-parallel simulation requires more real time to execute than a corresponding sequential simulation. Recurrent states of a simulation model provide a way to predict future states. In this paper, we propose a time-parallel simulation method which uses a pre-simulation to identify recurrent states. For simulation models in which recurrent states do not exist or can not support sufficient time parallelism, an approximation technique is suggested to extend the class of simulation models to which time-parallel simulation can be applied. Several queueing network models are investigated with the proposed time-parallel simulation. Experimental result suggest that the proposed approach can exploit massive parallelism while yielding accurate results.
Software system documentation process maturity model
Authors: Marcello Visconti, Curtis Cook
Venue: Proceedings of the 1993 ACM conference on Computer science (1993)

Low quality or missing documentation is a major cause of errors in software development and maintenance. We address this problem by proposing a 4-level Documentation Process Maturity model based on the Software Engineering Institute (SEI) Software Development Maturity model. We believe our model will be a useful tool in assessing an organization's documentation level and identifying improvement areas to move the organization to the next level.
A taxonomy of computer program security flaws
Authors: Carl E. Landwehr, Alan R. Bull, John P. McDermott, William S. Choi
Venue: ACM Computing Surveys (CSUR) (1994)

An organized record of actual flaws can be useful to computer system designers, programmers, analysts, administrators, and users. This survey provides a taxonomy for computer program security flaws, with an Appendix that documents 50 actual security flaws. These flaws have all been described previously in the open literature, but in widely separated places. For those new to the field of computer security, they provide a good introduction to the characteristics of security flaws and how they can arise. Because these flaws were not randomly selected from a valid statistical sample of such flaws, we make no strong claims concerning the likely distribution of actual security flaws within the taxonomy. However, this method of organizing security flaw data can help those who have custody of more representative samples to organize them and to focus their efforts to remove and, eventually, to prevent the introduction of security flaws.
On sparse matrix reordering for parallel factorization
Authors: B. Kumar, P. Sadayappan, C.-H. Huang
Venue: Proceedings of the 8th international conference on Supercomputing (1994)

To minimize the amount of computation and storage for parallel sparse factorization, sparse matrices have to be reordered prior to factorization. We show that none of the popular ordering heuristics proposed before, namely, mulitple minimum degree and nested dissection, perform consistently well over a range of matrices arising in diverse application domains. Spectral partitioning has been previously proposed as a means of generating small vertex separators for nested dissection of sparse matrices, so that the resulting ordering is amenable to efficient distributed parallel factorization with good load balance and low inter-processor communication. We show that nested dissection using spectral partitioning performs well for matrices arising from finite-element discretizations, but results in excessive fill compared to the minimum degree ordering for unstructured matrices such as power matrices and those arising from circuit simulation. The relative effectiveness of these two ordering schemes for parallel factorization is shown to vary widely for matrices arising from different application domains. We present an ordering strategy that performs consistently well for all matrix types. Its ordering is comparable or better than either minimum degree or nested dissection for all matrices evaluated. Performance results on the Intel iPSC/860 are reported.