ppxscal/embedding_network huggingface dataset:
A digital library and network for electronic teaching and learning materials for the Australian University system
Authors: Michael Greenhalgh
Venue: ACM SIGWEB Newsletter (1995)

ArtServe (http://rubens.anu.edu. all) went live on 4th January 1994, and currently gets about 2,800 accesses per day from all over the world. The material on offer consists of: (a) the Diocletian tutorial mentioned above; (b) 2,800 images of "Prints amp; Print History", together with their associated data files, available both with inline thumbnail images and via a fill-in-the-form database-query interface. The images date from the beginning of printmaking to about 1900, so as to avoid copyright problems; (c) 2,600 images of "Architecture of the Mediterranean Basin", currently available only via a fill-in-the-forms database-query interface; (d) a TextSearcher, commissioned by the author, which operates with plain ASCII text files and also with HTML files (see 6.2.2); (e) a 120,000-word book, written by the author, on "The Greek and Roman Cities of Western Turkey", "sliced up" into HTML format; (f) a further collection of images of Mediterranean art amp; architecture. Most images are accessible via a forms query interface, with the option of returning hotspotted records (i.e. for those with slow network connections) or records with inline GIFs as well.
Distributed simulation with locality
Authors: T. D. Blanchard, T. W. Lake
Venue: ACM SIGSIM Simulation Digest (1995)

We describe MOSS, a small language of mobile distributed objects and system-wide references, uncommitted to any distributed simulation protocol, but which can be executed as a distributed conservative simulation with automatic deduction of lookahead. We show how the MOSS programmer can control the dynamic distribution and locality of simulation objects by simple means which provide natural modelling functions. Preliminary results show how programmed locality can reduce communication costs in simulation.
SGTNE: semi-global time of the next event algorithm
Authors: Azzedine Boukerche, Carl Tropper
Venue: Proceedings of the ninth workshop on Parallel and distributed simulation (1995)

This paper describes an extension of the TNE algorithm, the objective of which is to increase its parallelism and to break the inter-processor deadlocks inherent with the use of TNE. The algorithm, which we call the SGTNE algorithm (Semi Global TNE), is executed over a cluster of processors as opposed to TNE, which is executed over a cluster of processes assigned to a single processor. SGTNE helps to break the inter-processor deadlocks by executing a shortest path algorithm over a snapshot of the LPs in a cluster of processors. This paper discusses the algorithm and its implementation and reports on the performance results of simulations of a partitioned FCFS queueing network model executed on the Intel Paragon A4 multiprocessor machine. We also examine the impact of partitioning on the efficient implementation of the SGTNE algorithm. The results obtained indicate that SGTNE yields good speedups and that a partitioning which makes use of a strongly connected component algorithm results in a reduction of 30% in the running time of a simulation when compared to simple partitioning strategies. The results also indicate that SGTNE outperforms TNE.
Bounds on the speedup and efficiency of partial synchronization in parallel processing systems
Authors: C. S. Chang, R. Nelson
Venue: Journal of the ACM (JACM) (1995)

In this paper, we derive bounds on the speedup and efficiency of applications that schedule tasks on a set of parallel processors. We assume that the application runs an algorithm that consists of N iterations and before starting its i+1st iteration, a processor must wait for data (i.e., synchronize) calculated in the ith iteration by a subset of the other processors of the system. Processing times and interconnections between iterations are modeled by random variables with possibly deterministic distributions. Scientific applications consisting of iterations of recursive equations are examples of such applications that can be modeled within this formulation. We consider the efficiency of applications and show that, although efficiency decreases with an increase in the number of processors, it has a nonzero limit when the number of processors increases to infinity. We obtain a lower bound for the efficiency by solving an equation that depends on the distribution of task service times and the expected number of tasks needed to be synchronized. We also show that the lower bound is approached if the topology of the processor graph is ldquo;spread-out,&rdquo; a notion we define in the paper.
Deriving structural hylomorphisms from recursive definitions
Authors: Zhenjiang Hu, Hideya Iwasaki, Masato Takeichi
Venue: Proceedings of the first ACM SIGPLAN international conference on Functional programming (1996)

In functional programming, small programs are often glued together to construct a complex program. Program fusion is an optimizing process whereby these small programs are fused into a single one and intermediate data structures are removed. Recent work has made it clear that this process is especially successful if the recursive definitions are expressed in terms of hylomorphisms. In this paper, we propose an algorithm which can automatically turn all practical recursive definitions into structural hylomorphisms making program fusion be easily applied.
Software testability: an experiment in measuring simulation reusability
Authors: J. Voas, J. Payne, R. Mills, J. McManus
Venue: ACM SIGSOFT Software Engineering Notes (1995)

Software reuse can be more readily enabled if the testing of the code in the previous environment is still applicable to the new environment. The reusability of previous verification efforts is an important parameter is assessing the &ldquo;immediate&rdquo; reusability of the code; in this paper, the verification technique that we are focusing on is software testing. This paper presents the use of a software testability measure, sensitivity analysis, as a quantitative assessment of the reusability of previous verification. The ability to reuse verification is a factor to consider in determining the reusability of code. We have applied this technique to a large NASA supersonic software simulation, High Speed Civil Transport (HSCT), and the reusability results of that application suggest a possible concern about the sufficiency of the original verification.
Alexandria Digital Library
Authors: Terence R. Smith, James Frew
Venue: Communications of the ACM (1995)

The goal of the Alexandria Digital Library Project is to develop a distributed system that provides a comprehensive range of library services for collections of spatially indexed and graphical information. While such collections include digitized maps and images as important special components, the Alexandria Digital Library will involve a very wide range of graphical materials and will include textual materials. Users of the Alexandria Digital Library will range from school children to academic researchers to members of the general public. They will be able to retrieve materials from the library on the basis of information content as well by reference to spatial location.
Adoption intention in GSS: relative importance of beliefs
Authors: Wynne W. Chin, Abhijit Gopal
Venue: ACM SIGMIS Database (1995)

Models used to study information technology (IT) adoption were adapted and applied to the group support systems (GSS) domain to determine their applicability and to assess the relative importance of beliefs about GSS in the context of adoption. The beliefs examined were relative advantage, ease of use, compatibility, and enjoyment. Four methods of measuring the relative importance of the belief constructs in predicting GSS adoption intention were evaluated. The methods involved Likert-scaled measures, conjoint measures, direct ratings of importance, and paired comparisons. Compositional analyses using three distinct models, regression, molar, and molecular, were conducted to examine the data collected under the first method. The results of the study demonstrated that the models and constructs used in other IT domains are indeed applicable in the GSS context. The relative importance of the beliefs did not converge across methods, although there was some agreement among the three compositional approaches as well as among the conjoint, direct rating, and paired comparison methods. The results point to the need for caution in utilizing and interpreting regression results and demonstrate the viability of alternative methods of studying adoption.
Arithmetic perceptrons
Authors: Sergio A. Cannas
Venue: Neural Computation (1995)

A feedforward layered neural network (perceptron) with one hidden layer, which adds two N-bit binary numbers is constructed. The set of synaptic strengths and thresholds is obtained exactly for different architectures of the network and for arbitrary N. These structures can be easily generalized to perform more complicated arithmetic operations (like subtraction).
Software distribution using Xnetlib
Authors: Jack Dongarra, Tom Rowan, Reed Wade
Venue: ACM Transactions on Mathematical Software (TOMS) (1995)

Xnetlib is a new tool for software distribution. Whereas its predecessor netlib uses email as the user interface to its large collection of public-domain mathematical software, Xnetlib uses an X Window interface and socket-based communication. Xnetlib makes it easy to search through a large distributed collection of software and to retrieve requested software in seconds.
Parallel matrix-vector product using approximate hierarchical methods
Authors: Ananth Grama, Vipin Kumar, Ahmed Sameh
Venue: Proceedings of the 1995 ACM/IEEE conference on Supercomputing (CDROM) (1995)

Matrix-vector products (mat-vecs) form the core of iterative methods used for solving dense linear systems. Often, these systems arise in the solution of integral equations used in electromagnetics, heat transfer, and wave propagation. In this paper, we present a parallel approximate method for computing mat-vecs used in the solution of integral equations. We use this method to compute dense mat-vecs of hundreds of thousands of elements. The combined speedups obtained from the use of approximate methods and parallel processing represent an improvement of several orders of magnitude over exact mat-vecs on uniprocessors. We demonstrate that our parallel formulation incurs minimal parallel processing overhead and scales up to a large number of processors. We study the impact of varying the accuracy of the approximate mat-vec on overall time and on parallel efficiency. Experimental results are presented for 256 processor Cray T3D and Thinking Machines CM5 parallel computers. We have achieved computation rates in excess of 5 GFLOPS on the T3D.
Web-based laboratories in the introductory curriculum enhance formal methods
Authors: Rhys Price Jones, Fritz Ruehr, Richard Salter
Venue: ACM SIGCSE Bulletin (1996)

In order to be effective, the content of the introductory curriculum must strike a proper balance between the highly motivating (i.e. "fun") aspects of programming and the development of sound scientific background and analytical thinking. As part of an NSF-funded Education Infrastructure project at Oberlin College, we have developed a curriculum that maintains a high level of scientific rigor, while making use of the new technology of HTML and the World Wide Web to instruct and motivate. We provide our students with an integrated experience which includes web-based guided-study laboratory materials, an interactive programming environment and a syllabus which emphasizes the interplay between abstract and formal concepts on the one hand, and concrete implementations and experimental investigations on the other. Scheme is used as the primary programming environment, to illustrate the salient features of the imperative and the object-oriented paradigms, along with the functional paradigm with which it is usually associated. We believe that our approach: 1) revitalizes the material for students who expect a more modern presentation; 2) provides a balanced view of competing perspectives on programming style and methodology; and 3) provides a well-balanced mixture of formal analysis and experimental measurement.In order to produce laboratory materials without the overhead entailed by creating them directly in HTML, we have developed a tool capable of abstracting the functionality and style of HTML documents; thus we can engage both faculty and student authors in the development of laboratories with a uniform style. The very tools used to develop the online materials are themselves an excellent illustration of the empowerment which results from a thorough understanding of the principles of abstraction.
An Optimal Instruction Scheduler for Superscalar Processor
Authors: Hong-Chich Chou, Chung-Ping Chung
Venue: IEEE Transactions on Parallel and Distributed Systems (1995)

Performance in superscalar processing strongly depends on the compiler's ability to generate codes that can be executed by hardware in an optimal or near optimal order. Generating optimal code is an NP-complete problem. However, there is a need for highly optimized code, such as in superscalar or real-time systems. In this paper, an instruction scheduling scheme for optimizing a program trace is proposed. Optimized code can be arrived at without much redundant work, if some important features in code are well explored and utilized in scheduling. To formalize the task, two abstract models, one for a superscalar processor and the other for a program trace, are given. These two models reflect most of the characteristics of the scheduling problem. The interrelations between instructions and partial schedules are thoroughly studied, and dominance and equivalence relations on them are defined. These relations are then used to reduce the solution space and eventually help to produce optimal schedules. The results of experiments that show the promise of the proposed scheme are also presented.Index Terms¿Pipeline processors, sequencing and scheduling, optimization, prune and search, and NP-completeness.
Elements of Style: Analyzing a Software Design Feature with a Counterexample Detector
Authors: Daniel Jackson, Craig A. Damon
Venue: IEEE Transactions on Software Engineering (1996)

We demonstrate how Nitpick, a specification checker, can be applied to the design of a style mechanism for a word processor. The design is cast, along with some expected properties, in a subset of Z. Nitpick checks a property by enumerating all possible cases within some finite bounds, displaying as a counterexample the first case for which the property fails to hold. Unlike animation or execution tools, Nitpick does not require state transitions to be expressed constructively, and unlike theorem provers, Nitpick operates completely automatically without user intervention. Using a variety of reduction mechanisms, it can cover an enormous number of cases in a reasonable time, so that subtle flaws can be rapidly detected.
Lattice frameworks for multisource and bidirectional data flow problems
Authors: Stephen P. Masticola, Thomas J. Marlowe, Barbara G. Ryder
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (1995)

Multisource data flow problems involve information which may enter nodes independently through different classes of edges. In some cases, dissimilar meet operations appear to be used for different types of nodes. These problems include bidirectional and flow-sensitive problems as well as many static analyses of concurrent programs with synchronization. K-tuple frameworks, a type of standard data flow framework, provide a natural encoding for multisource problems using a single meet operator. Previously, the solution of these problems has been described as the fixed point of a set of data flow equations. Using our k-tuple representation, we can access the general results of standard data flow frameworks concerning convergence time and solution precision for these problems. We demonstrate this for the bidirectional component of partial redundancy suppression and two problems on the program summary graph. An interesting subclass of k-tuple frameworks, the join-of-meets frameworks, is useful for reachability problems, especially those stemming from analyses of explicitly parallel programs. We give results on function space properties for join-of-meets frameworks that indicate precise solutions for most of them will be difficult to obtain.
Integrating collaborative problem solving throughout the curriculum
Authors: R. J. Daigle, Michael V. Doran, J. Harold Pardue
Venue: ACM SIGCSE Bulletin (1996)

Our graduates are ill-prepared for entry positions in industry. This is the message from a 1994 NSF task force comprised of members from academia and industry. Among the specific deficiencies cited were problem-solving skills and the ability to work in groups. In a recent publication, the authors described a group problem-solving model, Group Zig Zag, based on the Myers-Briggs Type Indicator. In this paper we show how the integration of a collaborative approach throughout the curriculum can be achieved by adopting the Group Zig Zag model.
A Simplicial Algorithm for Computing Robust Stationary Points of a Continuous Function on the Unit Simplex
Authors: Zaifu Yang
Venue: SIAM Journal on Control and Optimization (1996)

A simplicial algorithm is proposed to compute a robust stationary point of a continuous function $f$ from the $(n-1)$-dimensional unit simplex $S^{n-1}$ into $R^{n}$. The concept of robust stationary point is a refinement of the concept of stationary point of $f$ on $S^{n-1}$. Starting from an arbitrarily chosen interior point $v$ in $S^{n-1}$, the algorithm generates a piecewise linear path of points in $S^{n-1}$. This path is followed by alternating linear programming pivot steps and replacement steps in a specific simplicial subdivision of the relative interior of $S^{n-1}$. In this way an approximate robust stationary point of any a priori chosen accuracy is reached within a finite number of steps. The algorithm leaves the starting point along one out of $n!$ rays. When the path approaches the boundary of $S^{n-1}$, the mesh size of the triangulation along the path automatically goes to zero. This makes the algorithm different from all simplicial restart algorithms and homotopy algorithms known so far. Roughly speaking, the algorithm is a blend of a restart and a homotopy algorithm and maintains the basic properties of both. However, the algorithm does not need an extra dimension as homotopy algorithms do. Some examples are discussed.
Wide Area Technical Report Service: technical reports online
Authors: James C. French, Edward A. Fox, Kurt Maly, Alan L. Selman
Venue: Communications of the ACM (1995)

Wide Area Technical Report Service (WATERS) is a distributed database of computer science technical reports. Contributors are departments of computer science that make their reports, stored locally at their sites, available through World-Wide Web and a WAIS search engine. By using WATERS, anyone with access to the Internet can, using a client such as Mosaic browse, search, obtain abstract and bibliographic information, and retrieve technical reports online. The latter assumes that the user's WWW client is set up to launch viewers such as ghostview for Postscript files, xdvi for dvi files, and xtiff for TIFF page images.
Addressing student problems in learning computer graphics
Authors: Amnon Shabo, Mark Guzdial, John Stasko
Venue: ACM SIGGRAPH Computer Graphics (1996)

Our goal is to improve the performance of computer graphics students by including problem-solving activities and situating their knowledge of computer graphics in authentic problems. The framework for achieving this goal is based on the apprenticeship model of training and integrates four modules: bull; An interactive notes module which includes note pages, in-depth pages and a variety of activities such as interactive visualizations and algorithm animations, aimed at enforcing the acquisition of conceptual and factual knowledge. bull; A case library which consists of stories of projects in computer graphics and maps them to common problems encountered in these projects. bull; A problem-solving module which presents problems to the learner in a real-world context and provides him/her with support to solve the problems. bull; A collaborative tool to support the undertaking of complex projects by teams of students.
Routing and Transmitting Problems in de Bruijn Networks
Authors: Zhen Liu, Ting-Yi Sung
Venue: IEEE Transactions on Computers (1996)

De Bruijn graphs, both directed and undirected, have received considerable attention as architecture for interconnection networks. In this paper, we focus on undirected de Bruijn networks of radix d and dimension n, denoted by UB(d, n). We first discuss the shortest-path routing problem. We present properties of the shortest paths between any two vertices of UB(d, n) and propose two shortest-path routing algorithms, one of which has linear time complexity. Secondly, we study the transmitting problem. We establish a lower bound for the optimal transmitting time which implies in particular that the optimal transmitting problem is trivial for UB(d, n) when d¿ 5. We present a transmitting scheme on undirected binary de Bruijn networks UB(2, n) with transmitting time n¿ 1 for n¿ 5, and conjecture that the optimal transmitting time is n¿ 1 for UB(2, n), and n for UB(3, n) and UB(4, n).
Learning a decision boundary from stochastic examples: incremental algorithms with and without queries
Authors: Yoshiyuki Kabashima, Shigeru Shinomoto
Venue: Neural Computation (1995)

Even if it is not possible to reproduce a target input-output relation, a learning machine should be able to minimize the probability of making errors. A practical learning algorithm should also be simple enough to go without memorizing example data, if possible. Incremental algorithms such as error backpropagation satisfy this requirement. We propose incremental algorithms that provide fast convergence of the machine parameter &theta; to its optimal choice &theta;o with respect to the number of examples t. We will consider the binary choice model whose target relation has a blurred boundary and the machine whose parameter &theta; specifies a decision boundary to make the output prediction. The question we wish to address here is how fast &theta; can approach &theta;o, depending upon whether in the learning stage the machine can specify inputs as queries to the target relation, or the inputs are drawn from a certain distribution. If queries are permitted, the machine can achieve the fastest convergence, (&theta;-&theta;o)2 < O(t-1). If not, O(t-1) convergence is generally not attainable. For learning without queries, we showed in a previous paper that the error minimum algorithm exhibits a slow convergence (&theta;-&theta;o)2 < O(t-2/3). We propose here a practical algorithm that provides a rather fast convergence, O(t-4/5). It is possible to further accelerate the convergence by using more elaborate algorithms. The fastest convergence turned out to be O[(lnt)2t-1]. This scaling is considered optimal among possible algorithms, and is not due to the incremental nature of our algorithm.