ppxscal/embedding_network huggingface dataset:
Exact lower time bounds for computing Boolean functions on CREW PRAMs
Authors: Martin Dietzfelbinger, Mirosaw Kutyowski, Rüdiger Reischuk
Venue: Journal of Computer and System Sciences (1994)

The time complexity of Boolean functions on abstract concurrent-read exclusive-write parallel random access machines (CREW PRAMs) is considered. We improve results of Cook, Dwork, and Reischuk (SIAM J. Comput.15 (1986), 87-97), and extend work of Kutylowski (SIAM J. Comput.20 (1991), 824-833), who proved a lower time bound for the OR function on such machines that equals the upper bound. We provide a general means for obtaining exact (i.e., correct up to an additive constant) lower bounds, which works for many Boolean functions, in particular all symmetric functions. The new approach is based on the fact that Boolean functions can be represented as polynomials with integer coefficients and that the degree of such a polynomial can be taken as a complexity measure. For some functions, e.g., AND and PARITY, the exact time bound also holds for nondeterministic machines. For probabilistic machines, we obtain exact lower time bounds for PARITY in the unbounded error model and, utilizing results by Szegedy (Ph.D. dissertation, University of Chicago, 1989), prove a general lower bound valid for all Boolean functions in the bounded error model. We further show that the (bounded error) probabilistic time complexity of Boolean functions on CREW PRAMs differs at most by a constant factor from the deterministic time complexity. We also obtain exact bounds for machines that allow a few processors to try to write to the same cell simultaneously. These bounds are stronger than those which follow automatically from the exclusive-write bounds. No tight bounds for this model were known before.
Two-level grammars are more expressive than Type 0 grammars: or are they?
Authors: Dick Grune
Venue: ACM SIGPLAN Notices (1993)

Under some simple conditions, two-level grammars can generate languages with unbounded numbers of terminal symbols; Type 0 grammars cannot.
A generalized vision of some parallel bidiagonal systems solvers
Authors: Josep-L. Larriba-Pey, Juan J. Navarro, Oriol Roig, Angel Jorba
Venue: Proceedings of the 8th international conference on Supercomputing (1994)

In this paper, a review of methods for the solution of general bidiagonal systems of equations is done. Gaussian Elimination, the r-Cyclic Reduction family of algorithms and the Divide and Conquer algorithm are analyzed. A unified view of the three types of methods is proposed. The work is focussed on two basic aspects of the methods: parallelism and grain. The influence of the architecture of the target computer on the parallelism and grain of the methods is evaluated. In particular, vector processors are analyzed as target architecture and one vector processor of the Convex C-3480 is taken as a case study. For the special case of Divide and Conquer, a model is made in order to tune parallelism and grain for its optimal execution. Two conclusions can be outlined from the analysis of the methods. First, the execution time of the r-Cyclic Reduction family of algorithms is lower as r grows reaching a lower significative bound in r=9. This means that the classic use of Cyclic Reduction on vector computers is outdated from now on. Second, the higher rank versions of the r-Cyclic Reduction family of algorithms and the optimized version of Divide and Conquer behave similarly on vector computers.
Interfacing realities to the human body (abstract)
Authors: Myron W. Krueger
Venue: Proceedings of the 1993 ACM conference on Computer science (1993)

Almost 25 years ago, the first glimmerings of a revolution in the ways people interact with computers began to appear. However, it was not until the mid-1980s that radically new human interfaces started to be taken seriously. The ultimate computer interface is the human body and the human senses. This idea is now termed virtual reality. The idea works in that it has already changed how people think. The technology is moving rapidly into research labs, but much more slowly into the realm of practical applications. When the ultimate expression of this concept is achieved, any fantasy that can be imagined could be experienced. Long before that time, preliminary implementations of the idea will radically change how we interact with computers. This new technology changes the focus of computer science from the computer to the human. Instead of receiving input from a sedentary user, the computer now perceives the behavior of a mobile participant. It allows conceptual information to be presented perceptually. Similarly, by immersing the participant in a graphic world, this technology suggests a new approach to a host of old problems. By creating a telecommunication environment in which remote participants can share information as if they are together, it will change how we relate to each other. The advent of virtual reality can be seen as a major cultural event. Indeed, it is a medium in which content and aesthetics will be as important as technology. Current virtual reality orthodoxy assumes a goggles-and-gloves approach and is willing to encumber users with as much electronics as necessary to accomplish its purely technical ends. It is not likely that this attitude will succeed in the marketplace. Alternative approaches that instrument the environment instead of the body, but provide some of the functionality of virtual reality are more compatible with the existing workplace. It is likely that such approximations of virtual reality will be the first techniques that are widely used.
A Parallel Hash Join Algorithm for Managing Data Skew
Authors: Joel L. Wolf, Philip S. Yu, John Turek, Daniel M. Dias
Venue: IEEE Transactions on Parallel and Distributed Systems (1993)

Presents a parallel hash join algorithm that is based on the concept of hierarchicalhashing, to address the problem of data skew. The proposed algorithm splits the usualhash phase into a hash phase and an explicit transfer phase, and adds an extrascheduling phase between these two. During the scheduling phase, a heuristicoptimization algorithm, using the output of the hash phase, attempts to balance the loadacross the multiple processors in the subsequent join phase. The algorithm naturallyidentifies the hash partitions with the largest skew values and splits them as necessary,assigning each of them to an optimal number of processors. Assuming for concreteness aZipf-like distribution of the values in the join column, a join phase which is CPU-bound,and a shared nothing environment, the algorithm is shown to achieve good join phaseload balancing, and to be robust relative to the degree of data skew and the totalnumber of processors. The overall speedup due to this algorithm is compared to someexisting parallel hash join methods. The proposed method does considerably better in high skew situations.
Introduction to object-oriented database management systems (abstract)
Authors: David Maier
Venue: ACM SIGPLAN OOPS Messenger (1993)

Introduction to Object-Oriented Database Management Systems David Maier, Oregon Graduate Institute This tutorial begins by explaining object-oriented database management systems (OODBMS) in terms of what is the value added beyond record-oriented database systems and object-oriented programming languages. It presents most of the current commercial OODBMS and several advanced prototypes with particular attention to distinguishing them in their data models, application interfaces and system architectures. It will also contrast the OODBMS approach with extended relational systems. A goal of the tutorial is to give participants an appreciation for the consequences of design choices made in the different systems. It concludes with a critique of current market offerings, and suggests there are significant regions of the design space to explore, and needs of advanced applications that are still largely unmet by any database product. This tutorial is designed both for those considering investing in OODBs and those who just want to understand the technology. It assumes knowledge of object-oriented programming concepts, and some familiarity with conventional database systems, particularly relational databases.
Women and computers: what we can learn from science
Authors: Janet T. Kerner, Kathy Vargas
Venue: ACM SIGCSE Bulletin (1994)

The phenomenon of pipeline leakage exhibited in the field of computer science is also observed in all the sciences and mathematics. We can take advantages of the similarities between computer science and all the sciences to share the knowledge that has been gained to reverse this phenomenon. Two important factors that have been identified are (i) the number of math and science courses taken in high school and (ii) the view that many young women have of careers in science and computer science as being antisocial in nature. Our program addresses these factors by exposing the young women to the challenges of scientific and technical topics and by making role models and mentors readily accessible to young women who demonstrate an interest in science. After the common factors have been extracted to make all science more attainable and more attractive to women, each of the individual sciences, mathematics, and computer science can address any problems that are unique to that field.
Atomic snapshots of shared memory
Authors: Yehuda Afek, Hagit Attiya, Danny Dolev, Eli Gafni, Michael Merritt, Nir Shavit
Venue: Journal of the ACM (JACM) (1993)

This paper introduces a general formulation of atomic snapshot memory, a shared memory partitioned into words written (updated) by individual processes, or instantaneously read (scanned) in its entirety. This paper presents three wait-free implementations of atomic snapshot memory. The first implementation in this paper uses unbounded (integer) fields in these registers, and is particularly easy to understand. The second implementation uses bounded registers. Its correctness proof follows the ideas of the unbounded implementation. Both constructions implement a single-writer snapshot memory, in which each word may be updated by only one process, from single-writer, n-reader registers. The third algorithm implements a multi-writer snapshot memory from atomic n-writer, n-reader registers, again echoing key ideas from the earlier constructions. All operations require &THgr;(n2) reads and writes to the component shared registers in the worst case. &mdash;Authors' Abstract
What if there were desktop access to the computer science literature?
Authors: Dennis J. Brueni, Baziley T. Cross, Edward A. Fox, Lenwood S. Heath, Deborah Hix, Lucy T. Nowell, William C. Wake
Venue: Proceedings of the 1993 ACM conference on Computer science (1993)

What if there were an electronic computer science library? Consider the possibilities of having your favorite publications available within finger's reach. Consider Project Envision, an ongoing effort to build a user-centered database from the computer science literature. This paper describes the project's first year progress, stressing the underlying motivation, user-centered development, and the overall design.
Effects of participative management on the performance of software development teams
Authors: Woo Young Chung, Patricia J. Guinan
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)

Researchers and practitioners advocate a participative management style for improving employee productivity and job satisfaction. Field studies have shown that participation has a modest, yet positive influence on productivity and job satisfaction. For software development teams, however, management approaches such as the notion of the chief programmer suggest that participation might not be productive. Systematic research has not been conducted to investigate the importance of a participative management style when managing software development teams. In this study we examine the relationship between software development team members' participative style and team performance.We collected survey data from 573 respondents of 91 software development teams. 112 businesses and IS managers provided the performance ratings for the study. Findings suggest that two contextual factors, team size and the professional experience of team members moderate the relationship between participation and performance. In small teams that consist of experienced members, participation is strongly associated with team performance. Also, in large teams that consist of relatively inexperienced members, participation is significantly related to team performance. Other findings and implications are discussed in the paper.
How to stabilize a fixed point
Authors: Keith Briggs
Venue: ACM SIGNUM Newsletter (1994)

While reading the thesis on 'Renormalization in area preserving maps' by Robert Mackay (Princeton 1982), I noticed an intriguing method proposed for computing an unstable fixed point of a nonlinear operator, in the case where we know approximately the eigenvalue of the linearized operator. Mackay attributed this method to his advisor Martin Kruskal. Although simple and practical, I had not seen this idea before, and since an error in the thesis makes it unnecessarily difficult to follow, I thought this presentation would be of interest. All credit is due to Mackay and Kruskal.
Object-oriented project management (abstract)
Authors: Kenneth Rubin, Adele Goldberg
Venue: ACM SIGPLAN OOPS Messenger (1993)

Object-Oriented Project Management Kenneth Rubin Adele Goldberg, ParcPlace Object-oriented projects have to be managed properly to obtain the most benefits from object-oriented technology. This tutorial explains the effect of object-oriented technology on costs, staffing and choice of methodology. It describes the pitfalls that attend object-oriented projects so that you can avoid them, and explains the key processes, including development style, use of prototyping, and reuse. It gives specific guidelines for organizing projects, managing a reuse library, estimating the size and cost of projects, and introducing object-oriented technology into an organization.
Backward Error Estimates for Toeplitz Systems
Authors: J. M. Varah
Venue: SIAM Journal on Matrix Analysis and Applications (1994)

Given a computed approximate solution $\bar{x}$ to $Ax = b$, it is interesting to find nearby systems with $\bar{x}$ as exact solution and that have the same structure as $A$. This paper shows that the distance to these nearby structured systems can be much larger than for the corresponding general perturbation for general and symmetric Toeplitz systems. In fact, even the correctly rounded solution $\hat{x}$ may require a structured perturbation with terms as large as $\|\hat{x}\|$ times the machine precision.
Hilbert Polynomial of a Certain Ladder-Determinantal Ideal
Authors: Devadatta M. Kulkarni
Venue: Journal of Algebraic Combinatorics: An International Journal (1993)

A ladder-shaped array is a subset of a rectangular array which looks like a Ferrers diagram corresponding to a partition of a positive integer. The ideals generated by the p-by-p minors of a ladder-type array of indeterminates in the corresponding polynomial ring have been shown to be hilbertian (i.e., their Hilbert functions coincide with Hilbert polynomials for all nonnegative integers) by Abhyankar and Kulkarni &lsqb;3, p 53&ndash;76&rsqb;. We exhibit here an explicit expression for the Hilbert polynomial of the ideal generated by the two-by-two minors of a ladder-type array of indeterminates in the corresponding polynomial ring. Counting the number of paths in the corresponding rectangular array having a fixed number of &ldquo;turning points&rdquo; above the path corresponding to the ladder is an essential ingredient of the combinatorial construction of the Hilbert polynomial. This gives a constructive proof of the hilbertianness of the ideal generated by the two-by-two minors of a ladder-type array of indeterminates.
Turning away from talking heads: the use of video-as-data in neurosurgery
Authors: Bonnie A. Nardi, Heinrich Schwarz, Allan Kuchinsky, Robert Leichner, Steve Whittaker, Robert Sclabassi
Venue: Proceedings of the INTERACT '93 and CHI '93 conference on Human factors in computing systems (1993)

Studies of video as a support for collaborative work have provided little hard evidence of its utility for either task performance or fostering telepresence, i.e. the conveyance of a face-to-face like social presence for remotely located participants. To date, most research on the value of video has concentrated on &ldquo;talking heads&rdquo; video in which the video images are of remote participants conferring or performing some task together. In contrast to talking heads video, we studied video-as-data in which video images of the workspace and work objects are the focus of interest, and convey critical information about the work. The use of video-as-data is intended to enhance task performance, rather than to provide telepresence. We studied the use of video during neurosurgery within the operating room and at remote locations away from the operating room. The workspace shown in the video is the surgical field (brain or spine) that the surgeon is operating on. We discuss our findings on the use of live and recorded video, and suggest extensions to video-as-data including its integration with computerized time-based information sources to educate and co-ordinate complex actions among distributed workgroups.
Composing specifications
Authors: Martín Abadi, Leslie Lamport
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1993)

A rigorous modular specification method requires a proof rule asserting that if each component behaves correctly in isolation, then it behaves correctly in concert with other components. Such a rule is subtle because a component need behave correctly only when its environment does, and each component is part of the others' environments. We examine the precise distinction between a system and its environment, and provide the requisite proof rule when modules are specified with safety and liveness properties.
Implementing the NHT-1 application I/O benchmark
Authors: Samuel A. Fineberg
Venue: ACM SIGARCH Computer Architecture News (1993)

The NHT-1 I/O (Input/Output) benchmarks are a benchmark suite developed at the Numerical Aerodynamic Simulation Facility (NAS) located at NASA Ames Research Center. These benchmarks are designed to test various aspects of the I/O performance of parallel supercomputers. One of these benchmarks, the Application I/O Benchmark, is designed to test the I/O performance of a system while executing a typical computational fluid dynamics application. In this paper the implementation of this benchmark on three parallel systems located at NAS and the results obtained from these implementations are reported. The machines used were an 8 processor Cray Y-MP, a 32768 processor CM-2, and a 128 processor iPSC/860. The results show that the Y-MP is the fastest machine and has relatively well balanced I/O performance. I/O adds 2--40% overhead, depending on the number of processors utilized. The CM-2 is the slowest machine, but it has I/O that is fast relative to its computational performance. This resulted in typical I/O overheads on the CM-2 of less than 4%. Finally, the iPSC/860, while not as computationally fast as the Y-MP, is considerably faster than the CM-2. However, the iPSCI860's I/O performance is quite poor and can add overhead of more than 70%.
Turing's test and conscious thought
Authors: Donald Michie
Venue: Artificial Intelligence (1993)

Over forty years ago A. M. Turing proposed a test for intelligence in machines. Based as it is solely on an examinee's verbal responses, the Test misses some important components of human thinking. To bring these manifestations within its scope, the Turing Test would require substantial extension. Advances in the application of AI methods in the design of improved human-computer interfaces are now focussing attention on machine models of thought and knowledge from the altered standpoint of practical utility. &mdash;Author's Abstract
A taxonomy of issues in name systems design and implementation
Authors: A. K. Yeo, A. L. Ananda, E. K. Koh
Venue: ACM SIGOPS Operating Systems Review (1993)

In the last decade, name systems have grown from a single centrally-controlled server providing only host name to physical address mapping, to a complex system consisting of multiple and distributed servers, providing not only name mapping, but also general directory lookup services. These advances are due in part to the increase in size, complexity and heterogeneity of distributed systems. This paper presents a taxonomy of design and implementation issues in building a name system.
The structure of job attitudes among entry-level I/S professionals: a path-analytic analysis
Authors: Ephraim R. McLean, Norman B. Bryan, John R. Tanner, Stanley J. Smits
Venue: Proceedings of the 1993 conference on Computer personnel research (1993)

This paper reports on analyses done on data collected as part of an ongoing, longitudinal study of a national sample of information systems (I/S) professionals who have recently entered the work force. Path analysis, a form of structural equation modeling (SEM) used in exploratory studies where there is no definitive theory to be tested, was used to study the relationships among the subjects' demographics and their job preference and personal characteristics, and the characteristics of the I/S programs within the colleges and universities from which the subjects were recently graduated. The findings indicate that while young males from large, well-established I/S programs exhibit a good fit between their preferences and their work experiences, this is less true for others (i.e., females, older graduates, graduates from newer or small programs). The implications of these findings for management are discussed.
Report of the fifth IFIP WG2.7 working conference: engineering for human-computer interaction
Authors: James A. Larson
Venue: ACM SIGCHI Bulletin (1993)

Forty user interface experts from Europe, North America, Australia, and Asia participated in this working conference with the aim of investigating the nature, concepts, and construction of user interfaces for software systems. For five days, we held formal presentations, small working groups, and informal discussions about UIMS architecture, user studies, user interface adaptability, multimodality, and design guidelines. Under the direction from the athletic Finns, we also sweated in saunas, jumped into lakes, jogged in the rain, and rowed what seemed to be halfway to Great Britain.