ppxscal/embedding_network huggingface dataset:
Access to, usage of, and outcomes from an electronic messaging system
Authors: Ronald E. Rice, Douglas E. Shook
Venue: ACM Transactions on Information Systems (TOIS) (1988)

This study examines relationships among perceived accessibility to an electronic messaging system (EMS), computer-monitored and reported usage of the system by approximately 100 employees of one division of an aerospace firm, user's job type, perceived appropriateness of the EMS, and reported outcomes such as changes in effectiveness and use of paper-based media. Greater accessibility resulted in more usage and reported increases in effectiveness. Physical distance to a terminal affects the associations of other aspects of accessibility with usage and has a greater influence on these associations earlier in one's adoption process. Differences in job type showed statistically significant associations with usage, independent of the influence of accessibility. Computer-monitored and reported usage measures were only moderately correlated and were differentially associated with the access measures and with the two outcomes. The article ends by discussing implications for implementation and evaluation of computer-based communication systems, theories of media characteristics and information value, and methodological issues in using computer-monitored usage data.
Elimination of redundant array subscript range checks
Authors: Priyadarshan Kolte, Michael Wolfe
Venue: ACM SIGPLAN Notices (1995)

This paper presents a compiler optimization algorithm to reduce the run time overhead of array subscript range checks in programs without compromising safety. The algorithm is based on partial redundancy elimination and it incorporates previously developed algorithms for range check optimization. We implemented the algorithm in our research compiler, Nascent, and conducted experiments on a suite of 10 benchmark programs to obtain four results: (1) the execution overhead of naive range checking is high enough to merit optimization, (2) there are substantial differences between various optimizations, (3) loop-based optimizations that hoist checks out of loops are effective in eliminating about 98% of the range checks, and (4) more sophisticated analysis and optimization algorithms produce very marginal benefits.
Constructing a Hermitian Matrix from Its Diagonal Entries and Eigenvalues
Authors: Moody T. Chu
Venue: SIAM Journal on Matrix Analysis and Applications (1995)

Given two vectors $a,\lambda \in R^{n}$, the Schur--Horn theorem states that $a$ majorizes $\lambda$ if and only if there exists a Hermitian matrix $H$ with eigenvalues $\lambda$ and diagonal entries $a$. While the theory is regarded as classical by now, the known proof is not constructive. To construct a Hermitian matrix from its diagonal entries and eigenvalues therefore becomes an interesting and challenging inverse eigenvalue problem. Two algorithms for determining the matrix numerically are proposed in this paper. The lift and projection method is an iterative method that involves an interesting application of the Wielandt--Hoffman theorem. The projected gradient method is a continuous method that, besides its easy implementation, offers a new proof of existence because of its global convergence property.
Minimizing completion time of a program by checkpointing and rejuvenation
Authors: Sachin Garg, Yennun Huang, Chandra Kintala, Kishor S. Trivedi
Venue: Proceedings of the 1996 ACM SIGMETRICS international conference on Measurement and modeling of computer systems (1996)

Checkpointing with rollback-recovery is a well known technique to reduce the completion time of a program in the presence of failures. While checkpointing is corrective in nature, rejuvenation refers to preventive maintenance of software aimed to reduce unexpected failures mostly resulting from the "aging" phenomenon. In this paper, we show how both these techniques may be used together to further reduce the expected completion time of a program. The idea of using checkpoints to reduce the amount of rollback upon a failure is taken a step further by combining it with rejuvenation. We derive the equations for expected completion time of a program with finite failure free running time for the following three cases when; (a) neither checkpointing nor rejuvenation is employed, (b) only checkpointing is employed, and finally (c) both checkpointing and rejuvenation are employed.We also present numerical results for Weibull failure time distribution for the above three cases and discuss optimal checkpointing and rejuvenation that minimizes the expected completion time. Using the numerical results, some interesting conclusions are drawn about benefits of these techniques in relation to the nature of failure distribution.
Corpus-based static branch prediction
Authors: Brad Calder, Dirk Grunwald, Donald Lindsay, James Martin, Michael Mozer, Benjamin Zorn
Venue: ACM SIGPLAN Notices (1995)

Correctly predicting the direction that branches will take is increasingly important in today's wide-issue computer architectures. The name program-based branch prediction is given to static branch prediction techniques that base their prediction on a program's structure. In this paper, we investigate a new approach to program-based branch prediction that uses a body of existing programs to predict the branch behavior in a new program. We call this approach to program-based branch prediction, evidence-based static prediction, or ESP. The main idea of ESP is that the behavior of a corpus of programs can be used to infer the behavior of new programs. In this paper, we use a neural network to map static features associated with each branch to the probability that the branch will be taken. ESP shows significant advantages over other prediction mechanisms. Specifically, it is a program-based technique, it is effective across a range of programming languages and programming styles, and it does not rely on the use of expert-defined heuristics. In this paper, we describe the application of ESP to the problem of branch prediction and compare our results to existing program-based branch predictors. We also investigate the applicability of ESP across computer architectures, programming languages, compilers, and run-time systems. Averaging over a body of 43 C and Fortran programs, ESP branch prediction results in a miss rate of 20%, as compared with the 25% miss rate obtained using the best existing program-based heuristics.
Adding generic functions to Scheme
Authors: Thant Tessman
Venue: ACM SIGPLAN Notices (1995)

A generic function is a set of methods, all of which have equivalent semantics but each of which apply to different domains. This document describes how to augment the Scheme programming language with the capability to define multi-method generic functions. Also described are optimization issues and areas of potentially fruitful future exploration.
Information systems research at RWTH Aachen
Authors: Matthias Jarke
Venue: ACM SIGMOD Record (1995)

With about 8.000 researchers and 40.000 students, RWTH Aachen is the largest technical university in Europe. The science and engineering departments and their industrial collaborators offer a lot of challenges for database research.The chair Informatik V (Information Systems) focuses on the theoretical analysis, prototypical development, and practical evaluation of meta information systems. Meta information systems, also called repositories, document and coordinate the distributed processes of producing, integrating, operating, and evolving database-intensive applications.Our research approaches these problems from a technological and from an application perspective.On the one hand, we pursue theory and system aspects of the integration of deductive and object-oriented technologies. One outcome of this work is a deductive object manager called ConceptBase which has been developed over the past eight years and is currently used by many research groups and industrial teams throughout the world.On the other hand, a wide range of application-driven projects aims at building a sound basis of empirical knowledge about the demands on meta information systems, and about the quality of proposed solutions. They address application domains as diverse as requirements engineering, telecommunications, cooperative engineering, organization-wide quality management, evolution of chemical production processes, and medical knowledge management. They share the vision of supporting wide-area distributed cooperation not just by low-level interoperation technology but by exploiting conceptual product and process modeling.Under the direction of M. Jarke, Informatik V comprises three research groups with a total of twenty senior researchers and doctoral students: distributed information systems (leader: Dr. Manfred Jeusfeld), process information systems (Dr. Klaus Pohl), and knowledge-based systems (Prof. Wolfgang Nejdl). Database-related activities also exist in the Software Engineering and Applied Mathematics groups.
New Perturbation Bounds for the Unitary Polar Factor
Authors: Ren-Cang Li
Venue: SIAM Journal on Matrix Analysis and Applications (1995)

Let $A$ be an $m\times n$ ($m\ge n$) complex matrix. It is known that there is a unique polar decomposition $A=QH$, where $Q^*Q=I$, the $n\times n$ identity matrix, and $H$ is positive definite, provided $A$ has full column rank. This note addresses the following question: How much may $Q$ change if $A$ is perturbed? For the square case $m=n$ our bound, which is valid for any unitarily invariant norm, is sharper and simpler than that of Mathias [SIAM J. Matrix Anal. Appl., 14 (1993), pp.~588--597]. For the nonsquare case, a bound is also established for unitarily invariant norm, which has not been done in the literature.
Recommended curriculum for CS2, 1984: a report of the ACM curriculum task force for CS2
Authors: Elliot B. Koffman, David Stemple, Caroline E. Wardle
Venue: Communications of the ACM (1985)

A Report of the ACM Curriculum Task Force for CS2
Cyber-surfing: the state-of-the-art in client server browsing and navigation
Authors: Hal Berghel
Venue: ACM SIGCUE Outlook (1995)

Modern network technology has spawned an entirely new cybernetic experience: cyberspace surfing. This surfing is as much a social experience as an information gathering resource. While providing the communication infrastructure for an everincreasing percentage of the global population, it is also becoming the focal point of an identifiable sub-culture of cybernauts who are attracted to the Intenet as moths to light. There is every indication that the forthcoming cyberspace revolution will have an even more dramatic impact on society than the microcomputer revolution.In this paper we analyze the cyber-surfing experience from the point of view of the supportive client-server technologies involved. On the basis of this analysis and some emerging trends we speculate on the future of cyberspace.
Disturbance Decoupling with Pole Placement forStructured Systems: A Graph-Theoretic Approach
Authors: Jacob vander Woude, Kazuo Murota
Venue: SIAM Journal on Matrix Analysis and Applications (1995)

Structured systems are linear systems of which each of the coefficients in the matrices is either fixed to zero or an independent free parameter. In this paper the well-known disturbance decoupling problem with pole placement for such systems is studied and necessary and sufficient conditions for the generic solvability of the problem are derived. Generic solvability here means solvability in almost all cases. The conditions will be stated in terms of weighted matchings in a bipartite graph that easily can be associated with a structured system. The advantage of this is that the conditions then can be verified by means of well-known and efficient combinatorial algorithms.
Spatial hash-joins
Authors: Ming-Ling Lo, Chinya V. Ravishankar
Venue: ACM SIGMOD Record (1996)

We examine how to apply the hash-join paradigm to spatial joins, and define a new framework for spatial hash-joins. Our spatial partition functions have two components: a set of bucket extents and an assignment function, which may map a data item into multiple buckets. Furthermore, the partition functions for the two input datasets may be different.We have designed and tested a spatial hash-join method based on this framework. The partition function for the inner dataset is initialized by sampling the dataset, and evolves as data are inserted. The partition function for the outer dataset is immutable, but may replicate a data item from the outer dataset into multiple buckets. The method mirrors relational hash-joins in other aspects. Our method needs no pre-computed indices. It is therefore applicable to a wide range of spatial joins.Our experiments show that our method outperforms current spatial join algorithms based on tree matching by a wide margin. Further, its performance is superior even when the tree-based methods have pre-computed indices. This makes the spatial hash-join method highly competitive both when the input datasets are dynamically generated and when the datasets have pre-computed indices.
Dealing with Integral State Constraints in BoundaryControl Problems of Quasilinear Elliptic Equations
Authors: Eduardo Casas, Luis A. Fernandez
Venue: SIAM Journal on Control and Optimization (1995)

This paper deals with state-constrained optimal control problems governed by a quasilinear elliptic equation. These constraints are given in an integral form and depend on the state and its gradient. Equality and inequality constraints are simultaneously considered. Existence of a solution is investigated and some optimality conditions are obtained with the aid of Ekeland's variational principle.
With Quasilinear Queries EXP is not Polynomial Time Turing Reducible to Sparse Sets
Authors: Bin Fu
Venue: SIAM Journal on Computing (1995)

We investigate the lower bounds of queries required by the polynomial time Turing reductions from exponential time classes to the sets of small density. For complexity classes E= DTIME$(2^{O(n)})$ and EXP=DTIME$(2^{n^{O(1)}})$, the following results are shown in this paper. (1) For any $aProc. 2nd IEEE Conference on Structure in Complexity Theory, 1987, pp. 138-146],[Proc. 7th IEEE Conference on Structure in Complexity Theory, 1992, pp. 222-238].
Phonological analysis in typed feature systems
Authors: Steven Bird, Ewan Klein
Venue: Computational Linguistics (1994)

Research on constraint-based grammar frameworks has focused on syntax and semantics largely to the exclusion of phonology. Likewise, current developments in phonology have generally ignored the technical and linguistic innovations available in these frameworks. In this paper we suggest some strategies for reuniting phonology and the rest of grammar in the context of a uniform constraint formalism. We explain why this is a desirable goal, and we present some conservative extensions to current practice in computational linguistics and in nonlinear phonology that we believe are necessary and sufficient for achieving this goal.We begin by exploring the application of typed feature logic to phonology and propose a system of prosodic types. Next, taking HPSG as an exemplar of the grammar frameworks we have in mind, we show how the phonology attribute can be enriched so that it can encode multi-tiered, hierarchical phonological representations. Finally, we exemplify the approach in some detail for the nonconcatenative morphology of Sierra Miwok and for schwa alternation in French. The approach taken in this paper lends itself particularly well to capturing phonological generalizations in terms of high-level prosodic constraints.
Genetic algorithms in optimizing simulated systems
Authors: George Tompkins, Farhad Azadivar
Venue: Proceedings of the 27th conference on Winter simulation (1995)

Advances have been made in optimizing quantitative variables within a simulation model, and many methodologies now exist for this purpose. However, many of the design decisions which confront a system's users involve policy alternatives. Often, variables used to represent these alternatives are not only discrete but qualitative. This work seeks to develop a simulation-optimization methodology which can operate on qualitative variables. The proposed approach is to link a genetic algorithm with an object-oriented simulation model generator. The system designs recommended by the genetic algorithm are converted to simulation models and executed. The results then guide the genetic algorithm in its selection of future designs. A simulation model generator for a class of manufacturing systems and a genetic algorithm which can interface with the generator have been developed. The methodology has shown positive results.
An integrated approach to software reuse practice
Authors: E. Mambella, R. Ferrari, F. D. Carli, A. L. Surdo
Venue: ACM SIGSOFT Software Engineering Notes (1995)

Since 1993, Sodalia's Software Engineers have been studying a reuse program whose goal is making software reuse a significant and systematic part of the software process. The Sodalia's Corporate Reuse Program is intended to develop a Software Reuse Process that incorporates reuse-specific activities along the Object-Oriented Software Development Process, and a reuse library to support the classification and management of reusable components.This paper focuses on the on-going experience of Sodalia in the gradual introduction of reuse practice in the organization, illustrates the evolutionary stages, and the reached results.
A New Approach to the Main Conjecture on Algebraic-Geometric MDS Codes
Authors: Judy L. Walker
Venue: Designs, Codes and Cryptography (1996)

The Main Conjecture on MDS Codes states that for every linear [n,k] MDS code over {\Bbb F}_q, if 1 < k < q, then n \le q+1, except when q is even and k=3 or k=q-1, in which cases n \le q+2. Recently, there has been an attempt to prove the conjecture in the case of algebraic-geometric codes. The method until now has been to reduce the conjecture to a statement about the arithmetic of the jacobian of the curve, and the conjecture has been successfully proven in this way for elliptic and hyperelliptic curves. We present a new approach to the problem, which depends on the geometry of the curve after an appropriate embedding. Using algebraic-geometric methods, we then prove the conjecture through this approach in the case of elliptic curves. In the process, we prove a new result about the maximum number of points in an arc which lies on an elliptic curve.
Why looking isn't always seeing: readership skills and graphical programming
Authors: Marian Petre
Venue: Communications of the ACM (1995)

Many believe that visual programming techniques are quite close to developers. This article reports on some fascinating research focusing on understanding how textual and visual representations for software differ in effectiveness. Among other things, it is determined that the differences lie not so much in the textual-visual distinction as in the degree to which specific representations support the conventions experts expect.
Issues in using a DIS facility in analysis
Authors: Jack M. Kloeber,  Jr., Jack A. Jackson,  Jr.
Venue: Proceedings of the 27th conference on Winter simulation (1995)

This paper analyzes the future prospects for the use of the Theater Battle Arena (TBA) specifically, and Distributed Interactive Simulation (DIS) facilities in general, in conducting analysis for senior Air Force leadership. The desire is to broaden the use of the TBA in the arena of combat analysis. We believe that such a study would benefit other participants in the Advanced Distributed Simulation (ADS) environment as they plan, develop, construct, and upgrade facilities that take advantage of the still emerging ADS technology.
Finding the ith largest of n for small i,n
Authors: William Gasarch, Wayne Kelly, William Pugh
Venue: ACM SIGACT News (1996)

A classic problem in computer science is selection: given a list of n numbers, find the ith largest, using the fewest number of comparisons. We are interested in the exact number of comparisons required for specific small values of i and n. We have written a program that can be used either to find the exact number of comparisons for very low values of i and n, or to find upper bounds on the number of comparisons for slightly larger values of i and n. In some cases we have improved on the results in the literature and have additional improvements contingent on a conjecture.
Interprocedural compilation of irregular applications for distributed memory machines
Authors: Gagan Agrawal, Joel Saltz
Venue: Proceedings of the 1995 ACM/IEEE conference on Supercomputing (CDROM) (1995)

Data parallel languages like High Performance Fortran (HPF) are emerging as the architecture independent mode of programming distributed memory parallel machines. In this paper, we present the interprocedural optimizations required for compiling applications having irregular data access patterns, when coded in such data parallel languages. We have developed an Interprocedural Partial Redundancy Elimination (IPRE) algorithm for optimized placement of runtime preprocessing routine and collective communication routines inserted for managing communication in such codes. We also present two new interprocedural optimizations, placement of scatter routines and use of coalescing and incremental routines. We then describe how program slicing can be used for further applying IPRE in more complex scenarios. We have done a preliminary implementation of the schemes presented here using the Fortran D compilation system as the necessary infrastructure. We present experimental results from two codes compiled using our system to demonstrate the efficacy of the presented schemes.
AIgorithms: an integrated algorithm analysis, writing and artificial intelligence course
Authors: James H. Martin, Karl Winklmann
Venue: ACM SIGART Bulletin (1995)

This article describes an undergraduate course that combines the teaching of algorithms, artificial intelligence and technical writing. The primary goal of this course is to achieve a better integration of AI concepts and techniques into our undergraduate CS program. This integration is achieved through an alignment of material from existing AI and Algorithms classes.
Fast message assembly using compact address relations
Authors: Peter A. Dinda, David R. O'Hallaron
Venue: Proceedings of the 1996 ACM SIGMETRICS international conference on Measurement and modeling of computer systems (1996)

Message assembly and disassembly represent a significant fraction of total communication time in many parallel systems. We introduce a run-time approach for fast message assembly and disassembly. The approach is based on generating addresses by decoding a precomputed and compactly stored address relation that describes the mapping of addresses on the source node to addresses on the destination node. The main result is that relations induced by redistributions of regular block-cyclic distributed arrays can be encoded in an extremely compact form that facilitates high throughput message assembly and disassembly. We measure the throughput of decoding-based message assembly and disassembly on several systems and find performance on par with copy throughput.
On group communication in large-scale distributed systems
Authors: Özalp Babaoğlu, André Schiper
Venue: ACM SIGOPS Operating Systems Review (1995)

An increasing number of applications with reliability requirements are being deployed in distributed systems that span large geographic distances or manage large numbers of objects. We consider the process group mechanism as an appropriate application structuring paradigm in such large-scale distributed systems. We give a formal characterization for the attribute "large scale" as applied to distributed systems and examine the technical problems that need to be solved in making group technology scalable. Our design advocates multiple roles for group membership over a minimal set of abstractions and primitives. The design is currently being implemented on top of "off-the-shelf" technologies for both communication and computation.