ppxscal/embedding_network huggingface dataset:
A quantitative analysis of cache policies for scalable network file systems
Authors: Michael D. Dahlin, Clifford J. Mather, Randolph Y. Wang, Thomas E. Anderson, David A. Patterson
Venue: Proceedings of the 1994 ACM SIGMETRICS conference on Measurement and modeling of computer systems (1994)

Current network file system protocols rely heavily on a central server to coordinate file activity among client workstations. This central server can become a bottleneck that limits scalability for environments with large numbers of clients. In central server systems such as NFS and AFS, all client writes, cache misses, and coherence messages are handled by the server. To keep up with this workload, expensive server machines are needed, configured with high-performance CPUs, memory systems, and I/O channels. Since the server stores all data, it must be physically capable of connecting to many disks. This reliance on a central server also makes current systems inappropriate for wide area network use where the network bandwidth to the server may be limited.In this paper, we investigate the quantitative performance effect of moving as many of the server responsibilities as possible to client workstations to reduce the need for high-performance server machines. We have devised a cache protocol in which all data reside on clients and all data transfers proceed directly from client to client. The server is used only to coordinate these data transfers. This protocol is being incorporated as part of our experimental file system, xFS. We present results from a trace-driven simulation study of the protocol using traces from a 237 client NFS installation. We find that the xFS protocol reduces server load by more than a factor of six compared to AFS without significantly affecting response time or file availability.
Polymorphism by name for references and continuations
Authors: Xavier Leroy
Venue: Proceedings of the 20th ACM SIGPLAN-SIGACT symposium on Principles of programming languages (1993)

This article investigates an ML-like language with byname semantics for polymorphism: polymorphic objects are not evaluated once for all at generalization time, but re-evaluated at each specialization. Unlike the standard ML semantics, the by-name semantics works well with polymorphic references and polymorphic continuations: the naive typing rules for references and for continuations are sound with respect to this semantics. Polymorphism by name leads to a better integration of these imperative features into the ML type discipline. Practical experience shows that it retains most of the efficiency and predictability of polymorphism by value.
Toward a methodology of optimizing programs for high-performance computers
Authors: Rudolf Eigenmann
Venue: Proceedings of the 7th international conference on Supercomputing (1993)

This report describes experiences in porting the Perfect Benchmarks programs to the Alliant FX/8 and Cedar machines. Although there is much to learn before we can really say we know how to optimize programs successfully for parallel computers in general and for hierarchical shared-memory architectures in particular, it is hoped that this report will be helpful to those who are beginning to port and transform programs for parallel machines. Perhaps it is even an interesting reference for experts. In addition, this paper summarizes our experience with the programming tools we used and discusses tools that could have helped to increase the productivity of the optimization process. This information is believed to be a useful basis for future tool development projects.
Visualizing Features and Tracking Their Evolution
Authors: Ravi Samtaney, Deborah Silver, Norman Zabusky, Jim Cao
Venue: Computer (1994)

We describe basic algorithms to extract coherent amorphous regions (features or objects) from 2 and 3D scalar and vector fields and then track them in a series of consecutive time steps. We use a combination of techniques from computer vision, image processing, computer graphics, and computational geometry and apply them to data sets from computational fluid dynamics. We demonstrate how these techniques can reduce visual clutter and provide the first step to quantifying observable phenomena. These results can be generalized to other disciplines with continuous time-dependent scalar (and vector) fields.
An Algorithm for the Single-Input Pole Assignment Problem
Authors: Rafael Bru, Jose Mas, Ana M. Urbano
Venue: SIAM Journal on Matrix Analysis and Applications (1994)

B. N. Datta and K. Datta have proposed an efficient parallel algorithm for the single-input pole assignment problem when the spectrum set to be assigned is pairwise distinct and disjoint from the spectrum of the dynamical matrix. This paper first presents a theoretical analysis of that algorithm and then presents the necessary modifications on it for an arbitrary spectrum. Based on the modified algorithm, the authors present two new algorithms for the problem and give some results on controllability that are of independent interests.
Usability inspection methods: report on a workshop held at CHI'92, Monterey, CA, May 3&ndash;4, 1992
Authors: Robert Mack, Jakob Nielsen
Venue: ACM SIGCHI Bulletin (1993)

Usability inspection methods, based on informed intuition s about interface design quality, hold promise of providing faster, more cost-effective ways to generate usability evaluations, compared to empirical user evaluation methods . Examples of inspection methods include heuristic evaluation (Nielsen amp; Molich, 1990), usability walkthroughs (Bias, 1991 ; Karat amp; Bennett, 1991a, 1991b), cognitive walk -throughs (Lewis, Polson, Wharton amp; Reiman, 1990), and applications of guidelines in walkthroughs (Jeffries, Miller, Wharton, amp; Uyeda, 1991). These methods have been used in development for some time in one form or another (perhap s by other names), often because there is simply no alternative like user testing. Usability inspection methods have been an object of research in the last two years or so . Progress has been made in refining methods, and understanding their role i n usability engineering.
Information systems: educational offerings vs. industry needs&mdash;how well do they match?
Authors: Judith A. Knapp
Venue: Proceedings of the 1993 conference on Computer personnel research (1993)

This study describes relationships between educational institution and industry practices in the Information Systems area. It is based on the results of two surveys conducted in the Chicago metropolitan area. Each of the surveys was designed to answer specific questions related to curriculum issues and industry needs. In addition to the curriculum of choice, other specific areas of comparison are degrees, software, and hardware. Industry hiring practices and educational institutions' trends are also discussed. Industry and educational institutions appear to have similar expectations and should be encouraged to combine forces to achieve a common goal. The Information Systems students, who eventually become employees in industry, will benefit from each group's coordinated efforts.
EQUAL rights&mdash;and wrongs&mdash;in Lisp
Authors: Kent M. Pitman
Venue: ACM SIGPLAN Lisp Pointers (1993)

Operations in Lisp, Scheme, and other dynamically-typed languages typically dispatch on representational type information rather than intentional type information. Several broad classes of bugs and confusions can be traced to improper attempts to recover intentional type information from representation types.
Performance evaluation for various configuration of superscalar processors
Authors: Atsushi Inoue, Kenji Takeda
Venue: ACM SIGARCH Computer Architecture News (1993)

We present evaluation results on configuration of superscalar processors. We have developed tools for evaluating superscalar processors, which consists of an optimizing compiler and a configurable simulator. These tools can accept architectural parameters which characterize the configuration of target superscalar processors. We can estimate the most optimal performance of each configuration, as the compiler extracts the parallelism in application programs maximally and the execution on the simulator reflects the actual behavior of the target processor. By comparing exectution results on various configuration of processors, we can observe the effect of each architectural parameter and get optimal configuration of superscalar processor. We have evaluated the performance varying the following specification of superscalar processors; (1) The number of instructions the processor can issue maximally on each cycle (2) The number of functional units and memory ports (3) Latency of instructions. The results show that four instruction issue per cycle attains enough performance and the integer unit should have two ALUs and two memory ports for most integer programs tested here. For floating point programs, if programs are highly optimized, reducing instruction latency is more effective than having more functional units, in order to enhance the performance of superscalar processors.
Cocyclic Development of Designs
Authors: K. J. Horadam, W. De Launey
Venue: Journal of Algebraic Combinatorics: An International Journal (1993)

We present the basic theory of cocyclic development of designs, in which group development over a finite group G is modified by the action of a cocycle defined on G &times; G. Negacyclic and &omega;-cyclic development are both special cases of cocyclic development.Techniques of design construction using the group ring, arising from difference set methods, also apply to cocyclic designs. Important classes of Hadamard matrices and generalized weighing matrices are cocyclic.We derive a characterization of cocyclic development which allows us to generate all matrices which are cocyclic over G. Any cocyclic matrix is equivalent to one obtained by entrywise action of an asymmetric matrix and a symmetric matrix on a G-developed matrix. The symmetric matrix is a Kronecker product of back &omega;-cyclic matrices, and the asymmetric matrix is determined by the second integral homology group of G.We believe this link between combinatorial design theory and low-dimensional group cohomology leads to (i) a new way to generate combinatorial designs&semi; (ii) a better understanding of the structure of some known designs&semi; and (iii) a better understanding of known construction techniques.
On the Solutions of a Class of Continuous Linear Programs
Authors: Edward J. Anderson, Andrew B. Philpott
Venue: SIAM Journal on Control and Optimization (1994)

This paper discusses the form of solutions for a class of continuous linear programs called separated continuous linear programs. It is shown that under certain assumptions on the problem data the optimal solutions can be taken to be piecewise analytic functions. This yields a strong duality result as a corollary.
Generative networkload models for a single server environment
Authors: S. V. Raghavan, D. Vasukiammaiyar, Gunter Haring
Venue: Proceedings of the 1994 ACM SIGMETRICS conference on Measurement and modeling of computer systems (1994)

Any performance evaluation study requires a concise description of the workload under which the performance of the system is to be evaluated. Also, the repeatability of the experiments for different workload profiles, requires that the workload models generate the workload profiles parametrically. Such a model, should preferably be time-invariant, consistent and generative. We view the networkload as a sequence that can be generated from the rules of a Context Free Grammar (CFG). Our approach combines the established practice of viewing the workload as &ldquo;consisting of a hierarchy&rdquo; and the CFG description, to produce a generative networkload model. The networkload model is applied to a SingleServer-MultipleClients network by deriving the networkload model parameters from an operational SingleServer network of personal computers. The time-invariance and generative nature are verified experimentally. The usefulness of such a description of the networkload to study the resource management problems of a network, like the optimal allocation of clients to servers, is explored by using the generative model as input descriptor to a queueing network model of SingleServer network.
A browser for bibliographic information retrieval, based on an application of lattice theory
Authors: Gert Schmeltz Pedersen
Venue: Proceedings of the 16th annual international ACM SIGIR conference on Research and development in information retrieval (1993)

An application of mathematical lattice theory, called relationship lattices, is utilized to attack problems of operational bibliographic information retrieval. The proposed solution offers an interface to the information searcher enabling operation in a world of concepts, authors, and document records and their relationships. This hides the complexities of query language and database structures, and it allows to use a personally preferred terminology and to browse, query and download document records in a convenient way. The main component of the proposed solution is a personal thesaurus built up as a relationship lattice.
The Voxar Project (Parallel Ray-Tracing)
Authors: Paul Pitot
Venue: IEEE Computer Graphics and Applications (1993)

An implementation of the ray-tracing algorithm that is based on the Voxar parallel processing model, which simulates 3D physical phenomena, is discussed. The implementation of a general parallel ray-tracing program, and the implementation of Voxar are reviewed. Results of a performance evaluation of Voxar show that the machine's best points are its efficiency on complex ray-tree images and its parallel animation functionality. Its weak points are the insufficiency of the deadlock prevention strategy, the high cost of the communication system, the sequential generation of the primary rays, and the rigidity of the regular subdivision.
The generalized Schur decomposition of an arbitrary pencil A&ndash;&lgr;B&mdash;robust software with error bounds and applications. Part I: theory and algorithms
Authors: James Demmel, Bo Kågström
Venue: ACM Transactions on Mathematical Software (TOMS) (1993)

Robust software with error bounds for computing the generalized Schur decomposition of an arbitrary matrix pencil A &ndash; &lgr;B (regular or singular) is presented. The decomposition is a generalization of the Schur canonical form of A &ndash; &lgr;I to matrix pencils and reveals the Kronecker structure of a singular pencil. Since computing the Kronecker structure of a singular pencil is a potentially ill-posed problem, it is important to be able to compute rigorous and reliable error bounds for the computed features. The error bounds rely on perturbation theory for reducing subspaces and generalized eigenvalues of singular matrix pencils. The first part of this two-part paper presents the theory and algorithms for the decomposition and its error bounds, while the second part describes the computed generalized Schur decomposition and the software, and presents applications and an example of its use.
Adding disjunction to datalog (extended abstract)
Authors: Thomas Eiter, Georg Gottlob, Heikki Mannila
Venue: Proceedings of the thirteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems (1994)

We study the expressive power and complexity of disjunctive datalog, i.e., datalog with disjunctive rule heads, under three different semantics: the minimal model semantics, the perfect models semantics, and the stable model semantics. We show that the brave variants of these semantics express the same set of queries. In fact, they precisely capture the complexity of class &Sgr;P/2. The combined complexity of disjunctive datalog is shown to be NEXPTIMENP-complete.
Tachyon: a constraint-based temporal reasoning model and its implementation
Authors: Jonathan Stillman, Richard Arthur, Andrew Deitsch
Venue: ACM SIGART Bulletin (1993)

We provide an overview of Tachyon, an implementation of a constraint-based model for representing and reasoning about qualitative and quantitative aspects of time. Tachyon's data model provides substantial expressiveness, fast computation over convex intervals, and will serve as a testbed for topology-driven techniques for handling calculations over non-convex intervals. Our implementation of this model features a graphical interface using X-Windows and InterViews. We are currently exploring the use of Tachyon in a number of areas, including scheduling, project planning, feasibility analysis, and spatio-temporal data management.
Using Hindley-Milner type inference to optimise list representation
Authors: Cordelia V. Hall
Venue: Proceedings of the 1994 ACM conference on LISP and functional programming (1994)

Lists are a pervasive data structure in functional programs. The generality and simplicity of their structure makes them expensive. Hindley-Milner type inference and partial evaluation are all that is needed to optimise this structure, yielding considerable improvements in space and time consumption for some interesting programs. This framework is applicable to many data types and their optimised representations, such as lists and parallel implementations of bags, or arrays and quadtrees.
Cyclides in Surface and Solid Modeling
Authors: Dabasish Dutta, Ralph R. Martin, Michael J. Pratt
Venue: IEEE Computer Graphics and Applications (1993)

It is shown that Dupin cyclides (C.P. Dupin, 1822), as surfaces in computer-aided geometric design (CAGD), have attractive properties such as low algebraic degree, rational parametric forms, and an easily comprehensible geometric representation using simple and intuitive geometric parameters. Their alternative representations permit the transition between forms when one or the other is more convenient for a specific purpose. Cyclides provide is useful extension of geometric coverage in solid modeling, primarily as blending surfaces for many commonly occurring situations. The geometry, properties, and uses of the Dupin cyclide in free-form surface modeling and blending are discussed.
Computer-generated art, music, and literature: philosophical conundrums
Authors: Joseph S. Fulda
Venue: ACM SIGART Bulletin (1993)

What exactly is the meaning of "meaning"? Until Frege's seminal paper in 1892, " Uuml;ber Sinn und Bedeutung"---"On Sense and Reference"1---philosophers groped for an answer without much success. Frege's theory answered this question by observing that "H.G. Wells" has two sorts of meanings: reference, the man referred to, i.e., H.G. Wells himself, and sense, the meaning that H.G. Wells has for us, e.g., "The author of The War of the Worlds" and "The first true science fiction author." To Frege, every proper name has both a reference, also termed denotation, and one or more senses, also termed connotations. Various philosophical difficulties and paradoxes arise from the dichotomy of sense and reference, because neither aspect of meaning captures the other. Thus, reference does not capture the sense (one can know H.G. Wells without knowing that he authored The War of the Worlds), nor does sense capture reference (one can know that someone must have authored The War of the Worlds without knowing who), nor does one sense capture another (one can know that Wells wrote The War of the Worlds without knowing that many consider him the first true science fiction author). One paradox is that the substitutivity of identity fails. Thus it may be the case that Wells and the author of The War of the Worlds are identical, yet one can believe that the author of The War of the Worlds is the first true science fiction author without believing that Wells is the first true science fiction author, even though all that has been done is the substitution of identicals. There are also difficulties---not necessarily paradoxical---inherent in Frege's theory. For example, what is the reference for a fictional character in a play or novel? The philosophical literature on meaning, sense, and reference is vast, and we have but opened the door.
An innovative software reengineering tools workshop&mdash;a test of market maturity and lessons learned
Authors: Pierre Bourque, Alain Abran
Venue: ACM SIGSOFT Software Engineering Notes (1994)

Practitioners still feel ill at ease regarding an evaluation process for reengineering tools. To address this issue, a Qu eacute;bec-based special interest group in software engineering reused a case study workshop format that had been previously implemented to compare CASE products. This case study format had to be substantially modified to allow both vendors and participants to properly position the reengineering tools. For example, the workshop committee had to prepare reengineering frameworks, including a taxonomy of tools as well as legacy system selection criteria for the case study. This article also reports on the challenges met during the project as well as lessons learned: within a context of an immature reengineering market, the time has not yet come for a full real-life case study at an acceptable economic cost.
The Sperner Capacity of Linear and Nonlinear Codes for the Cyclic Triangle
Authors: A. R. Calderbank, P. Frankl, R. L. Graham, W.-C. W. Li, L. A. Shepp
Venue: Journal of Algebraic Combinatorics: An International Journal (1993)

Shannon introduced the concept of zero-error capacity of a discrete memoryless channel. The channel determines an undirected graph on the symbol alphabet, where adjacency means that symbols cannot be confused at the receiver. The zero-error or Shannon capacity is an invariant of this graph. Gargano, K&ouml;rner, and Vaccaro have recently extended the concept of Shannon capacity to directed graphs. Their generalization of Shannon capacity is called Sperner capacity. We resolve a problem posed by these authors by giving the first example (the two orientations of the triangle) of a graph where the Sperner capacity depends on the orientations of the edges.Sperner capacity seems to be achieved by nonlinear codes, whereas Shannon capacity seems to be attainable by linear codes. In particular, linear codes do not achieve Sperner capacity for the cyclic triangle. We use Fourier analysis or linear programming to obtain the best upper bounds for linear codes. The bounds for unrestricted codes are obtained from rank arguments, eigenvalue interlacing inequalities and polynomial algebra.The statement of the cyclic q-gon problem is very simple: what is the maximum size Nq(n) of a subset Sn of &lcub;0, 1, &hellip;, q&minus;1&rcub;n with the property that for every pair of distinct vectors x &equals; (xi), y &equals; (yi) &isin; Sn, we have xj&minus;yj &equiv; 1(mod q) for some j? For q &equals; 3 (the cyclic triangle), we show N3(n)&sime;2n. If however Sn is a subgroup, then we give a simple proof that \vert S_n\vert \leq \sqrt{3}^n.
A bibliography on parallel parsing
Authors: Henk Alblas, Rieks op den Akker, Paul Oude Luttighuis, Klaas Sikkel
Venue: ACM SIGPLAN Notices (1994)

This bibliography on parallel parsing and recognition of context-free languages covers most of the important publications in this area of computer science and natural language processing. The list of publications is preluded by an introduction which presents an overview of the field.
A SQL project as a learning method in a database course
Authors: Behrooz Seyed-Abbassi
Venue: Proceedings of the 1993 conference on Computer personnel research (1993)

This paper presents a learning method which is being used at the University of North Florida in the database processing class for Information Systems (IS) students. The method incorporates a major project utilizing Structured Query Language (SQL). This project enhances the students understanding of the theoretical concepts of relational database by providing a simulation of a business environment-like experience. The hands-on practice with SQL and the development of a database which considers the application of referential integrity increases the students awareness of the complex computer technology requirements within a business organization. This awareness and knowledge prepares the IS students for successful employment as IS personnel within the business community.