ppxscal/embedding_network huggingface dataset:
Design of an algorithm simulation and animation environment (ASA)
Authors: Mário André Mayerhofer, Carlos José Pereira de Lucena
Venue: ACM SIGCSE Bulletin (1992)

This paper proposes a computer based environment to aid in teaching algorithms. The environment is called ASA (Algorithm Simulator and Animator) and it is being developed for SENAC, a Brazilian company, associated to Brazilian National Commerce Confederation, responsible for technical education.The text discusses difficulties in teaching algorithms and suggests the computer as a tool capable of decreasing existing learning barriers. In this context we present the goal of the ASA project. We review other on going projects also oriented towards teaching about algorithms through computers which bear some influence on our work.In sequence, we present the ASA system's arquitecture. The system's three modules are described as: Algorithm Presentor, Animator (Data Animator and Code Animator) and Constructor.The experience gained in implementing the prototype is reported. Dificulties encountered and even implementation details are also reported. The experience provides insights for the project's future directions.We end by discussing the main research areas in operation, that are results from the experience gained.
Improving Disk Cache Hit-Ratios Through Cache Partitioning
Authors: Dominique Thiébaut, Harold S. Stone, Joel L. Wolf
Venue: IEEE Transactions on Computers (1992)

An adaptive algorithm for managing fully associative cache memories shared by several identifiable processes is presented. The on-line algorithm extends an earlier model due to H.S. Stone et al. (1989) and partitions the cache storage in disjoint blocks whose sizes are determined by the locality of the processes accessing the cache. Simulation results of traces for 32-MB disk caches show a relative improvement in the overall and read hit-ratios in the range of 1% to 2% over those generated by a conventional least recently used replacement algorithm. The analysis of a queuing network model shows that such an increase in hit-ratio in a system with a heavy throughput of I/O requests can provide a significant decrease in disk response time.
An efficient approach to removing geometric degeneracies
Authors: Ioannis Emiris, John Canny
Venue: Proceedings of the eighth annual symposium on Computational geometry (1992)

Our aim is to perturb the input so that an algorithm designed under the hypothesis of input non-degeneracy can execute on arbitrary instances. The deterministic scheme of [EmCa] was the first efficient method and was applied to two important predicates. Here it is extended in a consistent manner to another two common predicates, thus making it valid for most algorithms in computational geometry. It is shown that this scheme incurs no extra algebraic complexity over the original algorithm while it increases the bit complexity by a factor roughly proportional to the dimension of the geometric space. The second contribution of this paper is a variant scheme for a restricted class of algorithms that is asymptotically optimal with respect to the algebraic as well as the bit complexity. Both methods are simple to implement and require no symbolic computation. They also conform to certain criteria ensuring that the solution to the original input can be restored from the output on the perturbed input. This is immediate when the input to solution mapping obeys a continuity property and requires some case-specific work otherwise. Finally we discuss extensions and limitations to our approach.
An evaluation of phrasal and clustered representations on a text categorization task
Authors: David D. Lewis
Venue: Proceedings of the 15th annual international ACM SIGIR conference on Research and development in information retrieval (1992)

Syntactic phrase indexing and term clustering have been widely explored as text representation techniques for text retrieval. In this paper we study the properties of phrasal and clustered indexing languages on a text categorization task, enabling us to study their properties in isolation from query interpretation issues. We show that optimal effectiveness occurs when using only a small proportion of the indexing terms available, and that effectiveness peaks at a higher feature set size and lower effectiveness level for a syntactic phrase indexing than for word-based indexing. We also present results suggesting that traditional term clustering method are unlikely to provide significantly improved text representations. An improved probabilistic text categorization method is also presented.
Perspectives on social responsibility for the computing field
Authors: Karen A. Duncan
Venue: Proceedings of the 1992 ACM annual conference on Communications (1992)

The scale of contemporary social problems in arenas such as health care, education, or economics is so large the computing community must play a key role in finding solutions. This panel discusses the role of such institutions as ACM, CRA, CSTB, and NSF in initiating these and similar activities.
Information-Based Evaluation Criterion for Classifier's Performance
Authors: Igor Kononenko, Ivan Bratko
Venue: Machine Learning (1991)

In the past few years many systems for learning decision rules from examples were developed. As different systems allow different types of answers when classifying new instances, it is difficult to appropriately evaluate the systems' classification power in comparison with other classification systems or in comparison with human experts. Classification accuracy is usually used as a measure of classification performance. This measure is, however, known to have several defects. A fair evaluation criterion should exclude the influence of the class probabilities which may enable a completely uninformed classifier to trivially achieve high classification accuracy. In this paper a method for evaluating the information score of a classifier's answers is proposed. It excludes the influence of prior probabilities, deals with various types of imperfect or probabilistic answers and can be used also for comparing the performance in different domains.
A Comparison-Based Approach to Multicomputer System Diagnosis in Hybrid Fault Situations
Authors: Wojciech E. Kozlowski, Henryk Krawczyk
Venue: IEEE Transactions on Computers (1991)

A comparison-based system-level fault diagnosis model is considered. Provided the number of faulty units and the number of incorrect outcomes (in the sense that a fault-free unit evaluates a faulty one to be fault-free) do not exceed given bounds, the necessary and sufficient conditions for the comparison assignment to achieve correct and complete diagnosis are determined. An O(n mod E mod ) fault identification algorithm and optimal comparison assignments, in terms of minimum time of complete fault localization, are also proposed. The proposed diagnosis strategy can be performed concurrently with application tasks execution and the suitable comparison assignment can minimize the latency of fault identification. It makes the model more attractive for real-time applications.
Algorithm 692: Model implementation and test package for the Sparse Basic Linear Algebra Subprograms
Authors: David S. Dodson, Roger G. Grimes, John G. Lewis
Venue: ACM Transactions on Mathematical Software (TOMS) (1991)

This paper desribes a model implementation and test software for the Sparse Basic Linear Algebra Subprograms (Sparse BLAS). The Sparse BLAS perform vector operations common in sparse linear algebra, with the goal of providing efficient, but portable, implementations of algorithms for high performance computers. The model implementation provides a portable set of FORTRAN 77 Sparse BLAS for the use on machines where specially tuned implementations do not exist or are not required. The test software is designed to verify that tuned implementations meet the specifications of the Sparse BLAS and that implementations are correctly installed.
A subclass of Petri Nets as design abstraction for parallel architectures
Authors: Werner B. Joerg
Venue: ACM SIGARCH Computer Architecture News (1990)

In spite of their increasing popularity for modeling and performance analysis of parallel systems, Petri nets play only a marginal role in the area of synthesis of asynchronous hardware. It is suggested that a change in the perception of their role will lead to a cost effective design method for parallel asynchronous architectures. A hardware implementable subclass of Petri nets is presented that exploits conflicts as a nondeterministic scheduling feature and that offers token evaluation as an option for path selection. The net primitives, complemented with functional primitives, constitute the lowest abstractions for a data flow oriented design paradigm.
Query Optimization for Nontraditional Database Applications
Authors: Timos K. Sellis, Leonard Shapiro
Venue: IEEE Transactions on Software Engineering (1991)

Database query languages and their use for programming nontraditional applications, such as engineering and artificial intelligence applications, are discussed. In such environments, database programs are used to code applications that work over large data sets residing in databases. Optimizing such programs then becomes a necessity. An examination is made of various optimization techniques, and transformations are suggested for improving the performance of database programs. These transformations result in new equivalent database programs with better space and time performance. Several of these techniques apply to classical query languages, although extended query languages which include an iteration operator are specifically discussed.
Summary of the SIGOIS general membership survey October 1991
Authors: Nora Comstock, Cissy Yoes
Venue: ACM SIGOIS Bulletin (1992)

One of the initiatives of the SIGOIS leadership is to become more responsive to our members. In order for us to plan on how we could become more effective, we issued a general membership survey in October 1991.The information from these surveys has been summarized and is currently being used as we develop new directions, and strengthen old ones, for our organization. This is a report on the summary information from the survey and a look at how we are trying to apply what we have learned.
PAWS: A Performance Evaluation Tool for Parallel Computing Systems
Authors: Daniel Pease, Arif Ghafoor, Ishfaq Ahmad, David L. Andrews, Kamal Foudil-Bey, Thomas E. Karpinski, Mohammad A. Mikki, Mohamed Zerrouki
Venue: Computer (1991)

A description is given of PAWS (parallel assessment window system), a set of tools that provides an interactive user-friendly environment for analysis of existing, prototype, and conceptual machine architectures running a common application. PAWS consists of an application tool, an architectural characterization tool, a performance assessment tool, and an interactive graphical display tool. The application characterization tool provides a facility for evaluating the level and degree of an application's parallelism. The architecture characterization tool allows users to create, store, and retrieve descriptions of machines in a database. This approach permits users to evaluate conceptual machines before building any hardware. The performance assessment tool generates profile plots through the interactive graphical display tool. It shows both the ideal parallelism inherent in the machine-independent dataflow graph and the predicted parallelism of the partitioned dataflow graph on the target machine.
Reporting points in halfspaces
Authors: Jiří Matoušek
Venue: Proceedings of the 32nd annual symposium on Foundations of computer science (1991)

The author considers the halfspace range reporting problem: Given a finite set P of points in E/sup d/, preprocess it so that given a query halfspace gamma , the points of p intersection gamma can be reported efficiently. It is shown that, with almost linear storage, this problem can be solved substantially more efficiently than the more general simplex range searching problem. A data structure for halfspace range reporting in dimensions d>or=4 is given. It uses O(n log log n) space and O (n log n) deterministic preprocessing time. The query time is also given. Results for the halfspace emptiness problem, where one only wants to know whether P intersection gamma is empty, are also presented.
Hierarchical Contour-Based Segmentation of Dynamic Scenes
Authors: Lars Westberg
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1992)

A motion segmentation algorithm is introduced. The algorithm is based on the assumption of one coherent moving area (without holes) on a static background. It does coarse-to-fine pyramid-based boundary refinement that attempts to classify the blocks into three classes: inside, border, and outside.
On Workload Characterization of Relational Database Environments
Authors: Philip S. Yu, Ming-Syan Chen, Hans-Ulrich Heiss, Sukho Lee
Venue: IEEE Transactions on Software Engineering (1992)

A relational database workload analyzer (REDWAR) is developed to characterize the workload in a DB2 environment. This is applied to study a production DB2 system where a structured query language (SQL) trace for a two-hour interval and an image copy of the database catalog were obtained. The results of the workload study are summarized. The structure and complexity of SQL statements, the makeup and run-time behavior of transactions/queries, and the composition of relations and views are discussed. The results obtained provide the important information needed to build a benchmark workload to evaluate the alternative design tradeoffs of database systems.
Integrating perception with problem solving
Authors: Paul Benjamin, Alec Cameron, Leo Dorst, Madeleine Rosar, Hsiang-Lung Wu
Venue: ACM SIGART Bulletin (1991)

Problem solving is a process to convert the world from an initial state to a goal state. This paper describes an approach that interleaves perception with action in problem solving. We presume that an intelligent agent starts this process with uncertain knowledge about the initial state of the world, a specified goal state, a given set of permissible actions to alter the world state, and a given set of sensors to observe the partially understood world state. The task is to generate and execute a plan to reach a state in which the agent knows that it has reached the goal.Given a problem described by all feasible sequences of actions and perceptions applicable to coverting any given state to the goal state, we demonstrate how to construct plans that can guide both action and perception by achieving a sequence of subgoals and show it is equivalent to decomposing the representation of the problem into components corresponding to achieving subgoals. We first show that feasible sequences of actions can be decomposed into components, independent of perception, for instance through a principal series (in the case of a group, a subnormal series). This leads to subgoals with which certain observables can be associated. On the other hand, the perceptive problem can be decomposed by switching on sensors in series and performing actions that make the perceived state indistinguishable from the goal state. Finally, we show how perception can be intergrated with problem solving; we use perception to guide actions; hence, to reduce the overall cost of problem solving. The ideas are illustrated with problems taken from subgroups of Rubik's Cube; we are currently extending them to arbitrary semi-groups.
3-D Position Sensing Using a Passive Monocular Vision System
Authors: John Cardillo, Maher A. Sid-Ahmed
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1991)

Passive monocular 3-D position sensing is made possible by a new calibration scheme that relates depth to focus blur through a composite lens and aperture model. The calibration technique enables the recovery of absolute 3-D position coordinates from image coordinates and measured focus blur. A geometric model of the camera's position and orientation in space is used to transform the camera's imaging coordinates into world coordinates. The relationship between the world coordinate system and the screen coordinate system which includes the amount of focus blur, is developed by modeling the camera imaging arrangement. The modeling proceeds first through the perspective view from a pinhole camera located anywhere in space. The camera's lens and aperture system is investigated to find the relationship between depth and focus blur. The aspect ratio of the frame image is considered. Position accuracies comparable to those in stereo based vision systems are possible without the need for solving the difficult point of correspondence problem.
A flexible system call interface for interprocessor communication in a distributed memory multicomputer
Authors: Maria D. Maggio, David W. Krumme
Venue: ACM SIGOPS Operating Systems Review (1991)

The Multifaceted Communication System for the distributed memory NCUBE is an interprocessor communication system that supports many features useful for application programs: asynchronous, partially and fully synchronous calls in blocking and non-blocking modes, buffered and unbuffered transmissions, gather and scatter operations, broadcasting, a general pipe mechanism, and file operations. A major achievement of this design is the use of a single, consistent user interface. This paper describes the main features of that interface and the semantics of the operations it embodies.
Surface Parametrization and Curvature Measurement of Arbitrary 3-D Objects: Five Practical Methods
Authors: Ernest M. Stokely, Shang You Wu
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1992)

Curvature sampling of arbitrary, fully described 3-D objects (e.g. tomographic medical images) is difficult because of surface patch parameterization problems. Five practical solutions are presented and characterized-the Sander-Zucker approach, two novel methods based on direct surface mapping, a piecewise linear manifold technique, and a turtle geometry method. One of the new methods, called the cross patch (CP) method, is shown to be very fast, robust in the presence of noise, and is always based on a proper surface parameterization, provided the perturbations of the surface over the patch neighborhood are isotropically distributed.
Summary of database research activities at the University of Massachusetts, Amherst
Authors: K. Ramamritham, E. Moss, J. A. Stankovic, D. Stemple, B. Croft, D. Towsley
Venue: ACM SIGMOD Record (1992)

At the University of Massachusetts, we have been conducting research in the following database related areas: theoretical support for database system development, database programming languages, flexible concurrency control and transaction management, real-time databases, and information retrieval. The following is a summary of our research in each area.
Detection of similarities in student programs: YAP'ing may be preferable to plague'ing
Authors: M. J. Wise
Venue: Proceedings of the twenty-third SIGCSE technical symposium on Computer science education (1992)

It has argued that systems for detecting similarities in submitted programs must be based on the analysis of program structure. One such system is &ldquo;Plague&rdquo;. In this paper, some difficulties with the Plague system are outlined and a new system is described that achieves the same goals as Plague, but in a way that is both more portable and more easily customized to new target languages.
Folding RNA on the Cray-2
Authors: Michael Ess
Venue: Proceedings of the 1990 ACM/IEEE conference on Supercomputing (1990)

Predicting RNA folding is a very computationally intensive task, that depends heavily on the assumptions of the model of folding. The 'stem list method' provides a flexible framework to change the assumptions of the model, but the price for this flexibility is its large computational costs. A C implementation of the 'stem list method' is given for the Cray-2 that takes advantage of both vectorization and multi-tasking. This implementation of exhaustive, depth first searching may have uses in other applications.
Building an APL2 X-Windows interface for VM and AIX with a general APL2-to-C interface
Authors: John R. Jensen, Kirk A. Beaty
Venue: Proceedings of the international conference on APL '91 (1991)

This paper describes APL2/X, an interface between X-Windows and APL2, designed and built at the IBM Cambridge Scientific Center. It currently runs under VM/CMS and AIX. The APL2/X VM version of the interface uses the APL2 associated processor 11 to communicate with X. The APL2/X AIX version uses a new auxiliary processor, AP144, to achieve the same functionality.APL2/X enables all of the X-Windows Xlib calls and data-structures for use from the APL2 environment. In so doing, it enables APL2 to make use of a true windowing environment. Several APL2 sample programs using the interface have been coded to illustrate and validate the interface.The basic X-Windows Xlib is actually a large application written in C. APL2/X has therefore been built upon, as well as heavily influenced, a general APL2-to-C interface that runs on various platforms: APL2 under VM/CMS and MVS/TSO, APL2 for the RISC System/6000 trade; under AIX, and APL2/PC under PC/DOS.
Limits of control flow on parallelism
Authors: Monica S. Lam, Robert P. Wilson
Venue: ACM SIGARCH Computer Architecture News (1992)

This paper discusses three techniques useful in relaxing the constraints imposed by control flow on parallelism: control dependence analysis, executing multiple flows of control simultaneously, and speculative execution. We evaluate these techniques by using trace simulations to find the limits of parallelism for machines that employ different combinations of these techniques. We have three major results. First, local regions of code have limited parallelism, and control dependence analysis is useful in extracting global parallelism from different parts of a program. Second, a superscalar processor is fundamentally limited because it cannot execute independent regions of code concurrently. Higher performance can be obtained with machines, such as multiprocessors and dataflow machines, that can simultaneously follow multiple flows of control. Finally, without speculative execution to allow instructions to execute before their control dependences are resolved, only modest amounts of parallelism can be obtained for programs with complex control flow.
Teaching modeling and simulation to computing science students
Authors: Sandra J. Cynar
Venue: ACM SIGCSE Bulletin (1990)

This article discusses the contents of a course in modeling and simulation designed for Computer Engineering and Computer Science students. A discussion of the need for such a course precedes a description of the course content and assignments.
Problems, communications, and common sense
Authors: Lorenz Lercher, Hermann Kaindl
Venue: ACM SIGART Bulletin (1992)

Problem solving in the real world is a more general issue than what is currently understood under this notion in the majority of today's AI publications. Particularly, finding an appropriate formal representation of a given problem in the real world is very difficult even for humans. We think that this is reminiscent of the core difficulty of knowledge acquisition for knowledge acquisition for knowledge-based systems, i.e. modeling the real world. If a machine is to understand problem statements in natural language, much commonsense knowledge must be available. However, even if it were available, it would be very difficult to retrieve those chunks of knowledge necessary for the problem at hand. We propose a view of presenting a problem to a problem solver as an act of communication, which may provide hints for finding such knowledge.