ppxscal/embedding_network huggingface dataset:
The Necessary Conditions for Clos-Type Nonblocking Multicast Networks
Authors: Yuanyuan Yang, Gerald M. Masson
Venue: Proceedings of the 10th International Parallel Processing Symposium (1996)

Efficient interconnection networks are critical to the performance of large communication systems and parallel and distributed computing systems with hundreds or thousands of communication components. The well-known Clos network or v(m,n,r) network can be extended to provide full one-to-many or multicast capability. In this paper, we consider several typical routing control strategies for Clos-type nonblocking multicast networks, and derive the necessary conditions under which this type of network is nonblocking for arbitrary multicast assignments in the strict sense as well as under these control strategies. The necessary conditions derived are represented as the number of middle switches m \geq \Theta\left(n \frac{\log r}{\log \log r} \right ). These results match the sufficient nonblocking condition for the currently best available explicitly constructed, constant stage nonblocking multicast network and provide a basis for the optimal design of this type of multicast network.
Walking and Talking - Sharing Best Practice
Authors: Johan Lundin, Maria Magnusson
Venue: Proceedings IEEE International Workshop on Wireless and Mobile Technologies in Education (2002)

Moving towards more communication intensive organizations where work tends to become more mobile there is a growing need to support learning among knowledge workers. This paper reports on a study of a group of knowledge workers, working both closely together and sometimes geographically separated was carried out in order to find out how and when learning took place and when the need for learning was obvious and perhaps not satisfied. The interviews and observations indicated that the need for more flexible learning possibilities exceeds the ones provided. The results from the study are analyzed and discussed, after which we suggest pointers for design divided into the categories: Walking around, Around meetings, Formalizing intuition and Sharing feelings.
Dynamic Alignment and Distribution of Irregularly Coupled Data Arrays for Scalable Parallelization of Particle-in-Cell Problems
Authors: Wei-keng Liao, Chao-wei Ou, Sanjay Ranka
Venue: Proceedings of the 10th International Parallel Processing Symposium (1996)

Particle-in-cell (PIC) plasma simulation codes require two data arrays---particle array and field array---for storing the lists of particles and electromagnetic fields, respectively. In every iteration the two are updated based on the values of each other. The interaction between these two arrays is dynamic due to the movement of particles. Efficient parallelization of PIC requires the two data arrays to be load balanced and the amount of communication generated due to the interaction between them to be minimized. This requires dynamic distribution and alignment of the two arrays. In this paper we present fast and efficient methods for achieving this task at runtime. The implementation and performance of a relativistic electromagnetic PIC plasma simulation code on the CM-5 are described.
Checking Modification Tolerance
Authors: Mario Dal Cin
Venue: The 3rd IEEE International Symposium on High-Assurance Systems Engineering (1998)

We elaborate a relational framework which allows the modeling and analysis of unintended and fault-tolerant system behavior. The framework is based on the notions of concurrent finite state machines and on tolerance and error relations over the state set of these machines. The focus will be on permanent errors which modify the transition structure of these machines.
A Time-Optimal Solution for the Path Cover Problem on Cographs
Authors: Koji Nakano, Stephan Olariu, Albert Y. Zomaya
Venue: Proceedings of the 13th International Symposium on Parallel Processing and the 10th Symposium on Parallel and Distributed Processing (1999)

We show that the notoriously difficult problem of finding and reporting the smallest number of vertex-disjoint paths that cover the vertices of a graph can be solved time-and work-optimally for cographs. Our algorithm solves this problem in O(log n) time using n log n processors on the EREW-PRAM for an n-vertex cograph G represented by its cotree.
Deterministic Broadcasting Time in Radio Networks of Unknown Topology
Authors: Dariusz R. Kowalski, Andrzej Pelc
Venue: Proceedings of the 43rd Symposium on Foundations of Computer Science (2002)

In a seminal paper [3], Bar-Yehuda, Goldreich and Itai considered broadcasting in radio networks whose nodes know only their own label and labels of their neighbors. They claimed a linear lower bound on the time of deterministic broadcasting in such radio networks, by constructing a class of graphs of diameter 3, with the property that every broadcasting algorithm requires linear time on one of these graphs. Due to a subtle error in the argument, this result is incorrect. We construct an algorithm that broadcasts in logarithmic time on all graphs from [3]. Moreover, we show how to broadcast in sublinear time on all n -node graphs of diameter 0(log log n). On the other hand, we construct a class of graphs of diameter 4, such that every broadcasting algorithm requires time \Omega (\sqrt[4]{n}) on one of these graphs. In view of the randomized algorithm from [3], runnning in expected time O(Dlogn + log2n) on all n -node graphs of diameter D, our lower bound gives the first correct proof of an exponential gap between determinism and randomization in the time of radio broadcasting.
Robust shearsort on incomplete bypass meshes
Authors: Behrooz Parhami, Ching Yu Hung
Venue: Proceedings of the 9th International Symposium on Parallel Processing (1995)

An incomplete 2-D bypass mesh is a rectangular m/spl times/n grid of p processing elements (PEs) in which faulty PEs have been bypassed in their respective rows and columns. Thus, two PEs that are separated only by faulty PEs in the same row or column become neighbors. We show that given O(log m) PE faults in each column, a robust version of the sorting scheme known as shearsort has the same O(m+n log m) asymptotic time complexity on such an incomplete mesh as on a complete mesh. We also demonstrate how the ability to compute on incomplete meshes is relevant to fault tolerance by presenting reconfiguration schemes to convert meshes with faulty PEs into incomplete bypass meshes.
State Treemap: An Awareness Widget for Multi-Synchronous Groupware
Authors: Pascal Molli, Hala Skaf-Molli, Christophe Bouthier
Venue: Proceedings of the Seventh International Workshop on Groupware (2001)

Abstract: Awareness widgets facilitate coordination for both synchronous and asynchronous groupware systems. Unfortunately, they cannot be used for multi-synchronous groupware systems, where people work simultaneously but disconnected on the same project. With a group of architects, we have designed a new awareness widget for multi-synchronous groupware system called "State Treemap ". This widget shows the divergence states of shared objects using Shneiderman's treemap visualization. We have developed and integrated this widget in a platform for hosting virtual teams of architects. In this paper; we describe the motivations, the design and the realization of this original widget.
Perceptual Model of Handwriting Drawing Application to the Handwriting Segmentation Problem
Authors: Éric Anquetil, Guy Lorette
Venue: Proceedings of the 4th International Conference on Document Analysis and Recognition (1997)

A new handwriting modeling and segmentation approach is introduced for cursive letter and word analysis. For the letter analysis, the proposed method is based on the detection of a set of "perceptual anchorage points" to extract a priori pertinent strokes. This physical segmentation of the handwritten drawing enables us to conduct a logical modeling of letters with respect to the most stable strokes of each letter class. For the handwritten word analysis we present a constructive segmentation approach to overcome the word segmentation problem. The main idea is to locate "anchorage structures" in the word drawing based on the most robust strokes of the letters. This new approach of handwriting analysis has been implemented in a writer independent on-line handwriting recognition system. Experimental results are reported using a lexicon context of 1128, 7000 and 25000 words.
Document image similarity and equivalence detection
Authors: Jonathan J. Hull, John Cullen
Venue: Proceedings of the 4th International Conference on Document Analysis and Recognition (1997)

A hierarchical algorithm is presented for determining the similarity and equivalence of document images. Features extracted from the CCITT fax compressed representations of two images are compared to determine their visual similarity and whether they are equivalent. Pass codes in the compressed data are used as features. A fixed grid is imposed on the image and a feature vector is derived from the number of pass codes in each grid cell. The feature vectors are compared to locate a group of documents that are visually similar to the input image. The equivalence of two documents is determined by applying the Hausdorff distance to the two dimensional arrangement of pass codes in small patches of each image.
A Trace-Based Simulation of Pointer Swizzling Techniques
Authors: Mark L. McAuliffe, Marvin H. Solomon
Venue: Proceedings of the Eleventh International Conference on Data Engineering (1995)

Persistent object-oriented applications that traverse large object graphs can improve their performance by caching objects in main memory while they are being used. While caching offers large performance benefits, the techniques used to locate these cached objects in memory can still impede the application's performance. We present the results of a trace-based simulation study of pointer swizzling techniques (techniques for reducing the cost of access to cached objects). We used traces derived from actual persistent programs to find a class of swizzling techniques that performs well, yet permits changes to the contents of in-memory object caches over the lifetime of an application. Our study demonstrates the superiority of a class of techniques known as "indirect swizzling" for a variety of workloads and system configurations.
Parallel Load Balancing for Problems with Good Bisectors
Authors: Stefan Bischof, Ralf Ebner, Thomas Erlebach
Venue: Proceedings of the 13th International Symposium on Parallel Processing and the 10th Symposium on Parallel and Distributed Processing (1999)

Parallel load balancing is studied for problems with certain bisection properties. A class of problems has alpha-bisectors if every problem p of weight w(p) in the class can be subdivided into two subproblems whose weight (load) is at least an alpha-fraction of the original problem. A problem p is to be split into N subproblems such that the maximum weight among them is as close to w(p)/N as possible. It was previously known that good load balancing can be achieved for such classes of problems using Algorithm HF, a sequential algorithm that repeatedly bisects the subproblem with maximum weight. Several parallel variants of Algorithm HF are introduced and analyzed with respect to worst-case load imbalance, running-time, and communication overhead. For fixed alpha, all variants have running-time O(log N) and provide constant upper bounds on the worst-case load imbalance. Results of simulation experiments regarding the load balance achieved in the average case are presented.
A Dichotomy Theorem for Constraints on a Three-Element Set
Authors: Andrei A. Bulatov
Venue: Proceedings of the 43rd Symposium on Foundations of Computer Science (2002)

The Constraint Satisfaction Problem (CSP) provides a common framework for many combinatorial problems. The general CSP is known to be NP-complete; however, certainrestrictions on the possible form of constraints may affect the complexity, and lead to tractable problem classes. There is, therefore, a fundamental research direction, aiming to separate those subclasses of the CSP which are tractable, from those which remain NP-complete.In 1978 Schaefer gave an exhaustive solution of this problem for the CSP on a 2-element domain. In this paper we generalise this result to a classification of the complexity of CSPs on a 3-element domain. The main result states that every subclass of the CSP defined by a set of allowed constraints is either tractable or NP-complete, and the criterion separating them is that conjectured in [6, 8]. We also exhibit a polynomial time algorithmwhich, for a given set of allowed constraints, determines whether if this set gives rise to a tractable problem class. To obtain the main result and the algorithm we extensively use the algebraic technique for the CSP developed in [17] and [6, 8].
Designing Adaptable Real-Time Fault-Tolerant Parallel Systems
Authors: Célio Estevan Morón
Venue: Proceedings of the 10th International Parallel Processing Symposium (1996)

There are two fundamental aspects in the design of the real-time systems: to meet the real-time constraints and to be reliable. These two aspects are in conflict and usually are researched separately. To provide for fault-tolerance on one side, there is the need for a greater execution time; but on the other side real-time systems require tasks to be completed by their deadlines.There is a clear and urgent need for mechanisms that are able to integrate the real-time and the reliability requirements. So, it would be possible to address the real-time and fault-tolerance requirements together during the design of the system. This would make the development of reliable real-time systems simple and efficient. Our approach is based on the idea that if the system is adaptable then the reliability is easier to achieve. We have developed a mechanism, known as Real-Time Recoverable Action (RTR-Action), which integrates the real-time and the reliability requirements.
Optimal Wormhole Routing in the (n, d)-Torus
Authors: Stefan Bock, Friedhelm Meyer auf der Heide, Christian Scheideler
Venue: Proceedings of the 11th International Symposium on Parallel Processing (1997)

In this paper we consider wormhole routing in a d-dimensional torus of side length n. In particular, we present an optimal randomized algorithm for routing worms of length up to O(n/(d log n)^2), one per node, to random destinations. Previous algorithms only work optimally for two dimensions, or are a factor of log n away from the optimal running time. As a by-product, we develop an algorithm for the 2-dimensional torus that guarantees an optimal runtime for worms of length up to O(n/(log n)^2) with much higher probability than all previous algorithms.
M-Education: Bridging the Gap of Mobile and Desktop Computing
Authors: Umer Farooq, Wendy Schafer, Mary Beth Rosson, John M. Carroll
Venue: Proceedings IEEE International Workshop on Wireless and Mobile Technologies in Education (2002)

Mobile Education or M-Education is a new conceptual paradigm in the use of mobile and wireless technologies for education. M-Education encourages distributed peer collaboration over wireless devices and desktop computers to create opportunities for discovery and education in the field and community. It is a project-oriented approach that will use a wireless virtual community to facilitate the learning activities of teachers, students, and peers through collaboration in a distributed environment. M-Education is significantly different from existing mobile learning systems in that it leverages its collaborative activities from an existingdesktop-based online virtual community (MOOsburg), and thus offers a range of collaboration opportunities, such as synchronous and asynchronous interactions with peers, and viewing or changes to persistent data. In this paper, an innovative use of wireless and mobiletechnologies in education is explored as part of a scenario-based design process [7].
Spectral Gap and log-Sobolev Constant for Balanced Matroids
Authors: Mark Jerrum, Jung-Bae Son
Venue: Proceedings of the 43rd Symposium on Foundations of Computer Science (2002)

We compute tight lower bounds on the log-Sobolev constant of a class of inductively defined Markov chains, which contains the bases ¿ exchange walks for balanced matroidsstudied by Feder and Mihail. As a corollary, we obtain improved upper bounds for the mixing time of a variety of Markov chains. An example: the "natural" random walk on spanning trees of a graph G as proposed by Broder ¿ which has been studied by a number of authors ¿ mixes in time O(mn log n),wheren is the number of vertices of G and m the number of edges. This beats the best previous upper bound on this walk by a factor n2.
Implementing a STARI chip
Authors: Mark R. Greenstreet
Venue: Proceedings of the 1995 International Conference on Computer Design: VLSI in Computers and Processors (1995)

STARI is a high-speed signaling technique that uses both synchronous and self-timed circuits. To demonstrate STARI, a chip has been fabricated using the MOSIS 2/spl mu/ CMOS process. In a simple test fixture, it operates at data rates of 120 Mbits/sec over a pair of wires. Because STARl uses both synchronous and self-timed circuits, it provides an opportunity to compare these two design methods. The synchronous circuits of the STARI chip achieve rates of operation two to three times those of the self-timed circuits. However, the self-timed FIFO in the receiver provides robust compensation for clock skew that could not be achieved with synchronous circuitry alone. Thus, the STARI chip demonstrates advantages of combining these two design techniques.
Symbolic range propagation
Authors: William Blume, Rudolf Eigenmann
Venue: Proceedings of the 9th International Symposium on Parallel Processing (1995)

Many analyses and transformations in a parallelizing compiler can benefit from the ability to compare arbitrary symbolic expressions. In this paper, we describe how one can compare expressions by using symbolic ranges of variables. A range is a lower and upper bound on a variable. We describe how these ranges can be efficiently computed from the program test. Symbolic range propagation has been implemented in Polaris, a parallelizing compiler being developed at the University of Illinois, and is used for symbolic dependence testing, detection of zero-trip loops, determining array sections possibly referenced by an access, and loop iteration-count estimation.
Ocean Circulation on the Intel Paragon: Modeling and Implementation
Authors: Ka-Cheong Leung, Ishfaq Ahmad, Hsiao-Ming Hsu
Venue: Proceedings of the 10th International Parallel Processing Symposium (1996)

In this paper, we present the modeling and implementation of a grand- challenge problem in the field of scientific computation: the Primitive-Equation Numerical Ocean Circulation Model. We present the mathematical formulation of the model and propose a scheme for its parallel implementation. Optimizations are made through collective communications and various partitioning schemes. In our experiments using up to 100 processors on the Intel Paragon parallel computer, the proposed strategy yields an encouraging speedup and exhibits a sustained scalability with increasing both the problem and machine sizes. We consider barotropic continental shelf waves in a periodic channel as a test problem. The model has numerous applications in environmental studies and ocean sciences.
Parallel Program Archetypes
Authors: Berna L. Massingill, K. Mani Chandy
Venue: Proceedings of the 13th International Symposium on Parallel Processing and the 10th Symposium on Parallel and Distributed Processing (1999)

A parallel program archetype is an abstraction that captures the common features of a class of problems with similar computational structure and combines them with a parallelization strategy to produce a pattern of dataflow and communication. Such abstractions are useful in application development, both as a conceptual framework and as a basis for tools and techniques. This paper describes an approach to parallel application development based on archetypes and presents an example archetype with applications.
Compiler Analysis to Support Compiled Communication for HPF-Like Programs
Authors: Xin Yuan, Rajiv Gupta, Rami G. Melhem
Venue: Proceedings of the 13th International Symposium on Parallel Processing and the 10th Symposium on Parallel and Distributed Processing (1999)

By managing network resources at compile time, the compiled communication technique greatly improves the communication performance for communication patterns that are known at compile time. In order to support compiled communication, the compiler must estimate the run-time physical connection requirement (physical communication) of a program and partition the program into phases such that the underlying network can support the communications within each phase. Traditional communication analysis techniques represent the communication requirement in logical forms (logical communication) and are insufficient for compiled communication. In this paper, we describe the compiler algorithms that derive physical communications from logical communications and present a communication phase analysis algorithm that partitions a program into phases. These algorithms are implemented and evaluated in our E-SUIF compiler.
Separation Logic: A Logic for Shared Mutable Data Structures
Authors: John C. Reynolds
Venue: Proceedings of the 17th Annual IEEE Symposium on Logic in Computer Science (2002)

In joint work with Peter O'Hearn and others, based on early ideas of Burstall, we have developed an extension of Hoare logic that permits reasoning about low-level imperativeprograms that use shared mutable data structure.The simple imperative programming language is extended with commands (not expressions) for accessing and modifying shared structures, and for explicit allocation and deallocation of storage. Assertions are extended by introducing a "separating conjunction" that asserts that its sub-formulas hold for disjoint parts of the heap, and a closely related "separating implication". Coupled with the inductive definition of predicates on abstract data structures, this extension permits the concise and flexible description of structures with controlled sharing.In this paper, we will survey the current development of this program logic, including extensions that permit unrestricted address arithmetic, dynamically allocated arrays, and recursive procedures. We will also discuss promising future directions.
Research to Industry: Four Years of Observations in Classrooms Using a Network of Handheld Devices
Authors: Sarah M. Davis
Venue: Proceedings IEEE International Workshop on Wireless and Mobile Technologies in Education (2002)

This paper illustrates six areas of impact on education by a classroom network of handheld devices. The author draws from four years of observations of classes using two early network prototypes. Two areas of impact for students are anonymity of data submission to the group and the ability to see their data displayed in the group space. For teachers, the two areas are the ability to instantly assess how all students are doing at any time during a lesson and the ease with which the system shares data. Finally, two implications are highlighted. The networks' ability to facilitate exploratory data activities may make these types of activities more accessible to all teachers, and the ability of the network to let all students answer all questionsmay have an impact upon student engagement in the classroom.