ppxscal/embedding_network huggingface dataset:
A Knowledge-Based Approach to the Analysis of Loops
Authors: Salwa K. Abd-El-Hafiz, Victor R. Basili
Venue: IEEE Transactions on Software Engineering (1996)

This paper presents a knowledge-based analysis approach that generates first order predicate logic annotations of loops. A classification of loops according to their complexity levels is presented. Based on this taxonomy, variations on the basic analysis approach that best fit each of the different classes are described. In general, mechanical annotation of loops is performed by first decomposing them using data flow analysis. This decomposition encapsulates closely related statements in events, that can be analyzed individually. Specifications of the resulting loop events are then obtained by utilizing patterns, called plans, stored in a knowledge base. Finally, a consistent and rigorous functional abstraction of the whole loop is synthesized from the specifications of its individual events. To test the analysis techniques and to assess their effectiveness, a case study was performed on an existing program of reasonable size. Results concerning the analyzed loops and the plans designed for them are given.
The measurement of information systems effectiveness: evaluating a measuring instrument
Authors: Judy E. Scott
Venue: ACM SIGMIS Database (1995)

Information system effectiveness is an important phenomenon for both researchers and practitioners. Despite widespread interest, and the importance of the uses, there have been no efforts to validate Computerworld's Premier 100 rankings of information system effectiveness. This paper uses structural equation modeling in an attempt to validate the measuring instrument used to derive the Computerworld rankings.Alternative models for the measuring instrument are proposed. Using a reflective model, the findings raise doubts as to the reliability of the rankings, and both content validity and construct validity are also suspect. The reliability and validity are problematic because multiple indicators of the same construct must be homogeneous for it to make sense to combine them into a composite index. A solution to this problem is to represent information system effectiveness as a multidimensional construct, that is part of a causal model. Based on previous research in the area, suggestions are offered to improve the measuring instrument.
Providing better support for a class of decision support queries
Authors: Sudhir G. Rao, Antonio Badia, Dirk van Gucht
Venue: ACM SIGMOD Record (1996)

Relational database systems do not effectively support complex queries containing quantifiers (quantified queries) that are increasingly becoming important in decision support applications. Generalized quantifiers provide an effective way of expressing such queries naturally. In this paper, we consider the problem of processing quantified queries within the generalized quantifier framework. We demonstrate that current relational systems are ill-equipped, both at the language and at the query processing level, to deal with such queries. We also provide insights into the intrinsic difficulties associated with processing such queries. We then describe the implementation of a quantified query processor, Q2P, that is based on multidimensional and boolean matrix structures. We provide results of performance experiments run on Q2P that demonstrate superior performance on quantified queries. Our results indicate that it is feasible to augment relational systems with query subsystems like Q2P for significant performance benefits for quantified queries in decision support applications.
Accessing relational databases from the World Wide Web
Authors: Tam Nguyen, V. Srinivasan
Venue: ACM SIGMOD Record (1996)

With the growing popularity of the internet and the World Wide Web (Web), there is a fast growing demand for access to database management systems (DBMS) from the Web. We describe here techniques that we invented to bridge the gap between HTML, the standard markup language of the Web, and SQL, the standard query language used to access relational DBMS. We propose a flexible general purpose variable substitution mechanism that provides cross-language variable substitution between HTML input and SQL query strings as well as between SQL result rows and HTML output thus enabling the application developer to use the full capabilities of HTML for creation of query forms and reports, and SQL for queries and updates. The cross-language variable substitution mechanism has been used in the design and implementation of a system called DB2 WWW Connection that enables quick and easy construction of applications that access relational DBMS data from the Web. An end user of these DB2 WWW applications sees only the forms for his or her requests and resulting reports. A user fills out the forms, points and clicks to navigate the forms and to access the database as determined by the application.
Minimum Cost Paths in Periodic Graphs
Authors: Franz Hofting, Egon Wanke
Venue: SIAM Journal on Computing (1995)

We consider graphs with $d$-dimensional integral vector weights and rational cost values associated with the edges. We analyze the problem of finding a minimum cost path between two given vertices such that the vector sum of all edges in the path equals a given target vector $m$. The present paper shows that there are polynomial time algorithms for finding such a minimum cost $m$-path if the dimension of the vector weights is bounded by a constant and the vector weights are represented unary, where the general version is NP-complete under various restrictions,
Irredundant intervals
Authors: Donald E. Knuth
Venue: Journal of Experimental Algorithmics (JEA) (1996)

This expository note presents simplifications of a theorem due to Gyri and an algorithm due to Franzblau and Kleitman: Given a family F of m intervals on a linearly ordered set of n elements, we can construct in O(m+n)2 steps an irredundant subfamily having maximum cardinality, as well as a generating family having minimum cardinality. The algorithm is of special interest because it solves a problem analogous to finding a maximum independent set, but on a class of objects that is more general than a matroid. This note is also a complete, runnable computer program, which can be used for experiments in conjunction with the public-domain software of The Stanford GraphBase.
Compose: an object-oriented environment for parallel discrete-event simulations
Authors: Jay M. Martin, Rajive L. Bagrodia
Venue: Proceedings of the 27th conference on Winter simulation (1995)

Existing environments for parallel discrete-event simulation provide support for either conservative or optimistic algorithms, with very few supporting both. This paper describes a parallel simulation environment that supports the execution of a model using an existing adaptive simulation algorithm where sub-models may be synchronized using conservative or optimistic algorithms, and an object may dynamically change its mode of synchronization. The environment has been designed as a C++ class library and has been implemented on an IBM SP2 multicomputer.
Server-directed collective I/O in Panda
Authors: K. E. Seamons, Y. Chen, P. Jones, J. Jozwiak, M. Winslett
Venue: Proceedings of the 1995 ACM/IEEE conference on Supercomputing (CDROM) (1995)

We present the architecture and implementation results for Panda 2.0, a library for input and output of multidimensional arrays on parallel and sequential platforms. Panda achieves remarkable performance levels on the IBM SP2, showing excellent scalability as data size increases and as the number of nodes increases, and provides throughputs close to the full capacity of the AIX file system on the SP2 we used. We argue that this good performance can be traced to Panda's use of server-directed i/o (a logical-level version of disk-directed i/o [Kotz94b]) to perform array i/o using sequential disk reads and writes, a very high level interface for collective i/o requests, and built-in facilities for arbitrary rearrangements of arrays during i/o. Other advantages of Panda's approach are ease of use, easy application portability, and a reliance on commodity system software.
Partition based spatial-merge join
Authors: Jignesh M. Patel, David J. DeWitt
Venue: ACM SIGMOD Record (1996)

This paper describes PBSM (Partition Based Spatial-Merge), a new algorithm for performing spatial join operation. This algorithm is especially effective when neither of the inputs to the join have an index on the joining attribute. Such a situation could arise if both inputs to the join are intermediate results in a complex query, or in a parallel environment where the inputs must be dynamically redistributed. The PBSM algorithm partitions the inputs into manageable chunks, and joins them using a computational geometry based plane-sweeping technique. This paper also presents a performance study comparing the the traditional indexed nested loops join algorithm, a spatial join algorithm based on joining spatial indices, and the PBSM algorithm. These comparisons are based on complete implementations of these algorithms in Paradise, a database system for handling GIS applications. Using real data sets, the performance study examines the behavior of these spatial join algorithms in a variety of situations, including the cases when both, one, or none of the inputs to the join have an suitable index. The study also examines the effect of clustering the join inputs on the performance of these join algorithms. The performance comparisons demonstrates the feasibility, and applicability of the PBSM join algorithm.
Ordering Givens Rotations for Sparse $QR$ Factorization
Authors: M. I. Gillespie, D. D. Olesky
Venue: SIAM Journal on Matrix Analysis and Applications (1995)

The $QR$ factorization of a large, sparse matrix $A$ is frequently computed using Givens rotations. The precise order in which the rotations are applied can affect the amount of storage required. We present an ordering for the Givens rotations that, when $A$ has the Hall property, is optimal with regard to storage for $Q$ (a so-called "tight" ordering) and that preserves sparsity by restricting fill to those locations in $R$ that are necessarily nonzero. This ordering is of particular interest when $A$ does not have the strong Hall property and is not permuted into block upper trapezoidal form. We describe a bipartite graph model of sparse matrix structures and summarize the characterization of the structures of the factors $Q$ and $R$. We define the product of structures of matrices, determine the product of the structures of a sequence of Givens rotations, and specify a tight ordering for these transformations.
Daylight visual effects: an interactive multimedia courseware prototype for beginning design students
Authors: Tsai-Sun Lee, Mary Hardin
Venue: ACM SIGGRAPH Computer Graphics (1996)

Beginning design students often find that it is difficult to master the varied and complex issues of architectural daylighting within a short timescale. Daylight is very dynamic and difficult to capture, and students struggle to document and understand daylighting phenomena through the traditional approaches of physical modeling, graphic techniques and computations. However, computer graphics and multimedia technologies are becoming widely used in educational applications and can facilitate non-linear, interactive learning environments particularly suited to complex concepts.An interactive multimedia courseware prototype, Daylight Visual Effects (DVE), has been designed to provide a demonstration database and easy-to-use interface for beginning design students. Users gain or enhance knowledge about the visual effects of daylighting by reviewing relevant daylighting images, written information animations and 3D computer models in the DVE's database. A live demonstration of the DVE prototype will follow this brief discussion of its inception, development, effectiveness in the studio and potential for future modifications.
A gradient method on the initial partition of Fiduccia-Mattheyses algorithm
Authors: Lung-Tien Liu, Ming-Ter Kuo, Shih-Chen Huang, Chung-Kuan Cheng
Venue: Proceedings of the 1995 IEEE/ACM international conference on Computer-aided design (1995)

In this paper, a Fiduccia-Mattheyses (FM) algorithm incorporating a novel initial partition generating method is proposed. The proposed algorithm applies to both bipartitioning and multi-way partitioning problems with or without replication. The initial partition generating method is based on a gradient decent algorithm. On partitioning without replication, our algorithm achieves an average of 17% improvement over the analytical method, PARABOLI, on bipartitioning, 10% better than Primal-Dual method on 4-way partitioning and 51% better than net-based method. On partitioning allowing replication, our algorithm achieves an average of 23% improvement over the directed Fiduccia-Mattheyses algorithm on Replication Graph (FMRG) method on bipartitioning.
Training and scaling preference functions for disambiguation
Authors: Hiyan Alshawi, David Carter
Venue: Computational Linguistics (1994)

We present an automatic method for weighting the contributions of preference functions used in disambiguation. Initial scaling factors are derived as the solution to a least squares minimization problem, and improvements are then made by hill climbing. The method is applied to disambiguating sentences in the Air Travel Information System corpus, and the performance of the resulting scaling factors is compared with hand-tuned factors. We then focus on one class of preference function, those based on semantic lexical collocations. Experimental results are presented showing that such functions vary considerably in selecting correct analyses. In particular, we define a function that performs significantly better than ones based on mutual information and likelihood ratios of lexical associations.
Investigating DEs with CRACK and related programs
Authors: Thomas Wolf, Andreas Brand
Venue: ACM SIGSAM Bulletin (1995)

The aim of the package to be described is to try modularizing the investigation of differential equations for which there are no complete algorithms available yet. All, that is available for such problems are algorithms for special situations, e.g. when first integrals with a simple structure exist (e.g. polynomial in first derivatives) or when the problem has infinitesimal symmetries. In all such cases, finally a system of differential equations has to be solved which is overdetermined in the sense that more conditions have to be satisfied than there are unknown functions. To do a variety of such investigations efficiently, like a symmetry analysis, application of symmetries, determination of first integrals, differential factors, equivalent Lagrangians, the strategy is to have one package (CRACK) for simplifying DEs and solving simple DEs as effective as possible and to use this program as the main tool for all the above mentioned investigations. For each investigation there is then only a short program necessary to just formulate the necessary conditions in form of an overdetermined DE-system and to call CRACK to solve this, possibly in a number of successive calls. The examples below shall indicate the range of possible applications.
Synchronous Bandwidth Allocation in FDDI Networks
Authors: Qin Zheng, Kang G. Shin
Venue: IEEE Transactions on Parallel and Distributed Systems (1995)

It is well known that an FDDI token ring network provides a guaranteed throughput for synchronous messages and a bounded medium access delay for each node/station. However, this fact alone cannot effectively support many real-time applications that require the timely delivery of each critical message. The reason for this is that the FDDI guarantees a medium access delay bound to nodes, but not to messages themselves. The message-delivery delays may exceed the medium-access delay bound even if a node transmits synchronous messages at a rate not greater than the guaranteed throughput. We solve this problem by developing a synchronous bandwidth allocation (SBA) scheme which calculates the synchronous bandwidth necessary for each application to satisfy its message-delivery delay requirement. The result obtained in this paper is essential for effective use of the FDDI token ring networks in supporting such real-time communication as digital video/audio transmissions, and distributed control/monitoring.
Efficient construction of binary moment diagrams for verifying arithmetic circuits
Authors: Kiyoharu Hamaguchi, Akihito Morita, Shuzo Yajima
Venue: Proceedings of the 1995 IEEE/ACM international conference on Computer-aided design (1995)

BDD-based approaches cannot handle some arithmetic functions such as multiplication efficiently, while Binary Moment Diagrams proposed by Bryant and Chen provide compact representations for those functions. They reported a BMD-based polynomial-time algorithm for verifying multipliers. This approach requires high-level information such as specifications to subcomponents. This paper presents a new technique called backward construction which can construct BMDs directly from circuit descriptions without any high-level information. The experiments show that the computation time for verifying for n-bit multipliers is approximately n^4. We have successfully verified 64-bit multipliers of several type in 3-6 hours with 40 Mbyte of memory on SPARCstation10/51. This result outperforms previous BDD-based approaches for verifying multipliers.
Using inheritance to implement concurrency
Authors: Mordechai Ben-Ari
Venue: Proceedings of the twenty-seventh SIGCSE technical symposium on Computer science education (1996)

The Ada programming language is an excellent vehicle for teaching concurrent programming because support for concurrency has been designed into the language. The paper shows how primitives from other concurrent programming languages (occam, Linda, Joyce) can be simulated within Ada. This enables students to study other constructs without the overhead of learning a new language and programming environment. The simulations use inheritance which was introduced into the new Ada 95 standard. They can also be used as examples of inheritance when teaching object-oriented programming.
Vector multiprocessors with arbitrated memory access
Authors: Montse Peiron, Mateo Valero, Eduard Ayguadé, Tomás Lang
Venue: ACM SIGARCH Computer Architecture News (1995)

The high latency of memory accesses is one of the factors that most contribute to reduce the performance of current vector supercomputers. The conflicts that can occur in the memory modules plus the collisions in the interconnection network in the case of multiprocessors make that the execution time of applications increases significantly. In this work we propose a memory access method that for both cases of vector uniprocessors and multiprocessors allows to perform stream accesses with the smallest possible latency in the majority of the cases. The basic idea is to arbitrate the memory access by defining the order in which the memory modules are visited. The stream elements are requested out of order. In addition, the access method also reduces the cost of the interconnection network.
Three-dimensional computation visualization for computer graphics rendering algorithms
Authors: David A. Goldman, Richard R. Eckert, Maxine S. Cohen
Venue: Proceedings of the twenty-seventh SIGCSE technical symposium on Computer science education (1996)

Computation visualization or algorithm animation is becoming an increasingly popular and effective way of teaching, debugging, and analyzing algorithms. Over the past ten years, several algorithm animation systems have been produced. Proposed here is a new approach and framework for visualizing three-dimensional algorithms or computations. Implemented on a prototype algorithm animation system, this framework, termed the vector-guided view, produces insightful visualizations of three-dimensional computation by effectively solving the problems of 3D scene navigation. The creation of this framework was motivated by the desire to produce visualizations of an increasingly large and complex set of rendering algorithms now ubiquitous in the field of computer graphics. To show the potential of this framework, a dynamic visualization of a recursive ray-tracing program has been created. A brief summary of the algorithm animation system is presented.
The weakest failure detector for solving consensus
Authors: Tushar Deepak Chandra, Vassos Hadzilacos, Sam Toueg
Venue: Journal of the ACM (JACM) (1996)

We determine what information about failures is necessary and sufficient to solve Consensus in asynchronous distributed systems subject to crash failures. In Chandra and Toueg [1996], it is shown that W, a failure detector that provides surprisingly little information about which processes have crashed, is sufficient to solve Consensus in asynchronous systems with a majority of correct processes. In this paper, we prove that to solve Consensus, any failure detector has to provide at least as much information as W. Thus, W is indeed the weakest failure detector for solving Consensus in asynchronous systems with a majority of correct processes.
A general solution of the n-dimensional B-tree problem
Authors: Michael Freeston
Venue: Proceedings of the 1995 ACM SIGMOD international conference on Management of data (1995)

We present a generic solution to a problem which lies at the heart of the unpredictable worst-case performance characteristics of a wide class of multi-dimensional index designs: those which employ a recursive partitioning of the data space. We then show how this solution can produce modified designs with fully predictable and controllable worst-case characteristics. In particular, we show how the recursive partitioning of an n-dimensional dataspace can be represented in such a way that the characteristics of the one-dimensional B-tree are preserved in n dimensions, as far as is topologically possible i.e. a representation guaranteeing logarithmic access and update time, while also guaranteeing a one-third minimum occupancy of both data and index nodes.
Integer Programming for Array Subscript Analysis
Authors: Jaspal Subhlok, Ken Kennedy
Venue: IEEE Transactions on Parallel and Distributed Systems (1995)

We present a new method to determine whether a convex region contains any integer points. The method is designed for array subscript analysis in parallel programs. The general problem is whether a system of linear equalities and inequalities has an integer solution. A set of known techniques is used to transform the problem to that of finding whether a convex region contains any integer points. The main result of the paper is a set of new search procedures that identify an integer solution in a convex region, or prove that no integer solutions exist. They are based on the geometrical properties of convex regions that are not empty, but also do not contain any integer points. The results contribute to exact and efficient dependence and synchronization analysis of parallel programs.Index Terms¿Subscript analysis, dependence testing, integer programming, parallelizing compilers, parallel program analysis, synchronization analysis.
Windows of opportunity in electronic classrooms
Authors: Ben Shneiderman, Maryann Alavi, Kent Norman, Ellen Yu Borkowski
Venue: Communications of the ACM (1995)

Paradigm-shifting landmark buildings are cherished by their occupants and remembered because they reshape our expectations of schools, homes, or offices. Classic examples include Thomas Jefferson's communal design of the &ldquo;academical village&rdquo; at the University of Virginia where faculty and students lived close to classrooms, Frank Lloyd Wright's organic harmony with nature in Fallingwater (in western Pennsylvania) where the waterfall sounds and leafy surroundings offered a stress-reducing getaway for an urban executive, or Kevin Roche's open glass-walled Ford Foundation (in New York City) that promoted new team-oriented management strategies.