ppxscal/embedding_network huggingface dataset:
Segmented Operations for Sparse Matrix Computation on Vector Multiprocessors
Authors: Guy E. Blelloch, Michael A. Heroux, Marco Zagha
Venue:  (1993)

In this paper we present a new technique for sparse matrix multiplication on vector multiprocessors based on the efficient implementation of a segmented sum operation. We describe how the segmented sum can be implemented on vector multiprocessors such that it both fully vectorizes within each processor and parallelizes across processors. Because of our method''s insensitivity to relative row size, it is better suited than the Ellpack/Itpack or the Jagged Diagonal algorithms for matrices which have a varying number of non-zero elements in each row. Furthermore, our approach requires less preprocessing (no more time than a single sparse matrix-vector multiplication), less auxiliary storage, and uses a more convenient data representation (an augmented form of the standard compressed sparse row format). We have implemented our algorithm (SEGMV) on the Cray Y-MP C90, and have compared its performance with other methods on a variety of sparse matrices from the Harwell-Boeing collection and industrial application codes. Our performance on the test matrices is up to 3 times faster than the Jagged Diagonal algorithm and up to 5 times faster than Ellpack/Itpack method. Our preprocessing time is an order of magnitude faster than for the Jagged Diagonal algorithm. Also, using an assembly language implementation of SEGMV on a 16 processor C90, the NAS Conjugate Gradient benchmark runs at 3.5 gigaflops.
Checkpointing and Rollback-Recovery for Distributed Systems
Authors: Richard Koo, Sam Toueg
Venue:  (1985)

We consider the problem of bringing a distributed system to a consistent state after transient failures. We address the two components of this problem by describing a distributed algorithm to create consistent checkpoints, as well as a rollback-recovery algorithm to recover the system to a consistent state. In contrast to previous algorithms, they tolerate failures that occur during their executions. Furthermore, when a process takes a checkpoint, a minimal number of additional processes are forced to take checkpoints. Similarly, when a process rolls back and restarts after a failure, a minimal number of additional processes are forced to roll back with it. Our algorithms require each process to store at most two checkpoints in stable storage. This storage requirement is shown to be minimal under general assumptions.
Adding Polymorphic Abstraction to ML (Detailed Abstract)
Authors: A. J. Kfoury, J. B. Wells
Venue:  (1994)

Abstract The ML programming language restricts type polymorphism to occur only in the ``let-in'''' construct and requires every occurrence of a formal parameter of a function (a lambda abstraction) to have the same type. Milner in 1978 refers to this restriction (which was adopted to help ML achieve automatic type inference) as a serious limitation. We show that this restriction can be relaxed enough to allow universal polymorphic abstraction without losing automatic type inference. This extension is equivalent to the rank-2 fragment of system F. We precisely characterize the additional program phrases (lambda terms) that can be typed with this extension and we describe typing anomalies both before and after the extension. We discuss how macros may be used to gain some of the power of rank-3 types without losing automatic type inference. We also discuss user-interface problems in how to inform the programmer of the possible types a program phrase may have.
On the Linear-Cost Subtree-Transfer Distance between Phylogenetic Trees
Authors: Bhaskar DasGupta, Xin He, Tao Jiang, Ming Li, John Tromp
Venue:  (1997)

Different phylogenetic trees for the same group of species are often produced either by procedures that use diverse optimality criteria [14] or from different genes [10] in the study of molecular evolution. Comparing these trees to find their similarities and dissimilarities (i.e. distance) is thus an important issue in computational molecular biology. Several distance metrics including the nearest neighbor interchange (nni) distance and the subtree-transfer distance have been proposed and extensively studied in the literature. This article considers a natural extension of the subtree-transfer distance, called the linear-cost subtree-transfer distance, and studies the complexity and efficient approximation algorithms for this distance as well as its relationship to the nni distance. The linear-cost subtree-transfer model seems more logical than the (unit-cost) subtree-transfer model in some applications. The following is a list of our results. 1. The linear-cost subtree-transfer distance is in fact identical to the nni distance on unweighted phylogenies. 2. There is an algorithm to compute an optimal linear-cost subtree-transfer sequence between unweighted phylogenies in O(n^2 log n + n 2^{O(d)}) time, where d denotes the linear-cost subtree-transfer distance. Such an algorithm is usual when d is small. 3. Computing the linear-cost subtree-transfer distance between two weighted phylogenetic trees is NP-hard, provided we allow multiple leaves of a tree to share the same label (i.e. the trees are not necessarily uniquely labeled). 4. There is an efficient approximation algorithm for computing the linear-cost subtree-transfer distance between weighted phylogenies with performance ratio 2.
A Scalable Cache Coherent Architecture for Large-Scale Mesh-Connected Multiprocessors
Authors: Yunseok Rhee, Joonwon Lee
Venue: Proceedings of the 1997 International Symposium on Parallel Architectures, Algorithms and Networks (1997)

Until now, various limited directory-based cache coherence protocols were proposed for medium- or large-scale multiprocessors while employing scalable directory memories. For widely shared data, however, most protocols suffer from extraneous cache invalidates or updates due to insufficient pointers. We focus on large-scale mesh-connected multiprocessors built on top of wormhole and dimension ordered routing networks. In such networks, worms are major bricks for communications, which transit all the intermediate nodes on its way to a destination. From such an observation, we propose a new directory-based protocol "DirQ" with limited pointers, which can represent either one node or a set of nodes when being widely shared. For sqrt{N} x sqrt{N} processors system, our protocol needs \Theta(N^{3/2}\log{N}) bits for directory memory which is much more scalable compared to the full-map protocol. In terms of latency and traffic volume for cache coherence, our analytic models show that "Dir Q" outperforms other limited protocols, and further comparable to the full-map one.
A Dynamic Probe Strategy for Quorum Systems
Authors: Mitchell L. Neilsen
Venue: Proceedings of the 17th International Conference on Distributed Computing Systems (ICDCS '97) (1997)

A quorum system is a collection of non-empty sets called quorums. Any two quorums in a quorum system must have at least one element in common. Quorum systems can be used for many different applications in a distributed system. A quorum system is available, if all elements in at least one quorum are operational. Elements can be probed to determine if they are operational. A probe strategy is used to determine the order in which the elements should be probed.This paper studies the average case probe complexity, which is the expected number of probes required to determine if a given quorum system is available. Then, two new probe strategies are presented and analyzed. The first strategy is a generalization of the alternating color strategy, and the second strategy is based on a measure of the relative importance of each element in the system.
Formally Verifying Hybrid Protocols with the Nuprl Logical Programming Environment
Authors: Mark Bickford, Christoph Kreitz, Robbert van Renesse
Venue:  (2001)

We describe a generic switching protocol for the construction of hybrid protocols and prove it correct with the Nuprl proof development system. We introduce the concept of meta-properties to characterize communication properties that can be preserved by switching and identify switching invariants that an implementation of the switching protocol must satisfy in order to work correctly. Our work shows how a theorem prover with a rich specification language can contribute to the design and implementation of verifiably correct adaptive protocols and that it can have a large impact when being engaged at the earliest stages of the design.
Statistical Physics Model for the Collective Price Fluctuations of Portfolios
Authors: Jun-ichi Maskawa
Venue: Proceedings of the Fourth International Conference on Computational Intelligence and Multimedia Applications (2001)

A statistical physics mode for the collective price changes of stock portfolios is proposed.That is an analogue to spin glass model for disordered magnetic system.In this model the time series of price change are coded into the sequences of up and down spins.Thehamiltonian of the system is expressed by long-range spin-spin interactions as inSherrinton-Kirtpatrick model of spin glass.The interaction efficients between two staks Are determined by empirical data using fluctuation-response theorem.Our theory is applied to price changes of stocks in Dow-Jones industrial portfolio.Monte Carlo simulations are performed based on the model.The resultant probability distributions of magnetization show good agreement with empirical data. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
Adsmith: An Efficient Object-Based Distributed Shared Memory System On Pvm
Authors: Chun-Ta King
Venue: Proceedings of the 1996 International Symposium on Parallel Architectures, Algorithms and Networks (1996)

In this paper, we describe an object-based distributed shared memory called Adsmith. In an object-based DSM, the shared memory consists of many shared objects, through which the shared memory is accessed. Adsmith is built on top of PVM at the library layer using C++. PVM is used as the communication subsystem because it is a de facto standard and encapsulates many system related details. Several mechanisms are used to improve the performance of Adsmith, such as release memory consistency, load/store-like memory accesses, nonblocking accesses, and atomic operations, etc. Performance results show that even though Adsmith is implemented on top of PVM, programs running on Adsmith can achieve a performance comparable with those running directly on PVM.
A Parallel Build-up Algorithm for Global Energy Minimizations of Molecular Clusters Using Effective Energy Simulated Annealing
Authors: Thomas F. Coleman, David Shalloway, Zhijun Wu
Venue:  (1993)

This work studies the build-up method for the global minimization problem for molecular conformation, especially protein folding. The problem is hard to solve for large molecules using general minimization approaches because of the enormous amount of required computation. We therefore propose a build-up process to systematically "construct" the optimal molecular structures. A prototype algorithm is designed using the anisotropic effective energy simulated annealing method at each build-up stage. The algorithm has been implemented on the Intel iPSC/860 parallel computer, and tested with the Lennard-Jones microcluster conformation problem. The experiments showed that the algorithm was effective for relatively large test problems, and also very suitable for massively parallel computation. In particular, for the 72-atom Lennard-Jones microcluster, the algorithm found a structure whose energy is lower than any others found in previous studies.
Protocol visualization using LOTOS multi-rendezvous mechanism
Authors: K. Yasumoto, T. Higashino, T. Matsuura, K. Taniguchi
Venue: Proceedings of the 1995 International Conference on Network Protocols (1995)

In this paper, we propose a method for visualizing LOTOS specifications using multi-rendezvous mechanism. For visualization, we have extended LOTOS by introducing some primitive animation events. Using the extended LOTOS, we describe a visualization scenario for events where we would like to visualize their execution. Then, we execute the original specification and its visualization scenario in parallel under LOTOS multi-rendezvous mechanism so that the corresponding animation is activated when each event is executed. The pair of the original specification and its visualization scenario is converted into the multi-threaded object code using our LOTOS compiler. In our visualization method we can specify the visualization scenario without modifying the original specification, and we can derive an object code which animates the original specification in real time. We have tried to visualize a LOTOS specification of "Dijkstra's dining philosophers", and evaluated the usefulness of our approach
Visual Contextual Awareness in Wearable Computing
Authors: Thad Starner, Bernt Schiele, Alex Pentland
Venue: Proceedings of the 2nd IEEE International Symposium on Wearable Computers (1998)

Small, body-mounted video cameras enable a different style of wearable computing interface. As processing power increases, a wearable computer can spend more time observing its user to provide serendipitous information, manage interruptions and tasks, and predict future needs without being directly commanded by the user. This paper introduces an assistant for playing the real-space game Patrol. This assistant tracks the wearer's location and current task through computer vision techniques and without off-body infrastructure. In addition, this paper continues augmented reality research, started in 1995, for binding virtual data to physical locations.
Transient Bitflip Injection in Microprocessor Embedded Applications
Authors: R. Velazco, S. Rezgui
Venue: Proceedings of the 6th IEEE International On-Line Testing Workshop (IOLTW) (2000)

In this paper is investigated a new methodology for transient bitflip injection, randomly in time and location, in microprocessor-based digital architectures. Experimental results performed on two different architectures illustrate the potentialities of this new strategy.
A quadratic approximation for protein sequence to structure mapping
Authors: SeYoung Oh, Jae Heon Yun, Sei-Young Chung
Venue: The Korean Journal of Computational Applied Mathematics (2003)

A method is proposed to predict the distances between given residue pairs (between Cα atoms) of a protein using a sequence to structure mapping by indefinite quadratic approximation The prediction technique requires a data fitting in three dimensional space with coordinates of the residues of known structured proteins and leads to a numerical representation of 20 amino acids by minimizing a large least norm iteratively. These approximations are used in distance prediction for given residue pairs. Some computational experience on a test set of small proteins from Brookhaven Protein Data Bank are given.
Functional Database Query Languages as Typed Lambda Calculi of Fixed Order
Authors: Gerd G. Hillebrand, Paris Kanellakis
Venue:  (1995)

We present a functional framework for database query languages that is analogous to the conventional logical framework of first-order and fixpoint formulas over finite structures. We use atomic constants of order~0, equality among these constants, variables, application, lambda abstraction, and {\tt let} abstraction; all typed using fixed order ($\leq 5$) functionalities. In this framework, proposed in [HKM93] for arbitrary order functionalities, queries and databases are both typed lambda terms, evaluation is by reduction, and the main programming technique is list iteration. We define two families of languages: TLI$^=_i$ or simply-typed list iteration of order~$i+3$ with equality, and MLI$^=_i$ or ML-typed list iteration of order~$i+3$ with equality; we use $i+3$ since our list representation of databases requires at least order~3. We show that: $\hbox{FO-queries} \subseteq \hbox{TLI}^=_0 \subseteq \hbox{MLI}^=_0 \subseteq \hbox{LOGSPACE-queries} \subseteq \hbox{TLI}^=_1 = \hbox{MLI}^=_1 = \hbox{PTIME-queries} \subseteq \hbox{TLI}_2$, where equality is no longer a primitive in TLI$_2$. We also show that ML type inference, restricted to fixed order, is polynomial in the size of the program typed. Since programming by using low order functionalities and type inference is common in functional languages, our results indicate that such programs suffice for expressing efficient computations and that their ML-types can be efficiently inferred.
Scaling End-to-End Multicast Transports with a Topologically-Sensitive Group Formation Protocol
Authors: Sylvia Ratnasamy, Steven McCanne
Venue: Proceedings of the Seventh Annual International Conference on Network Protocols (1999)

While the IP unicast service has proven successful, extending end-to-end adaptation to multicast has been a difficult problem. Unlike the unicast case, multicast protocols must support large and heterogeneous receiver sets. While proposed approaches to scaling multicast transports attempt to localize problems and/or organize receivers into a hierarchy through a divide-and-conquer approach, this approach succeeds only if the resulting hierarchy is congruent with the underlying routing tree topology. This implies the need for some level of topological information at the end systems which the IP multicast service deliberately hides.In this paper, we present a Group Formation Protocol (GFP) whereby receivers dynamically organize themselves into a multilevel hierarchy of multicast groups that corresponds to the underlying routing tree. GFP can serve as a core component across a wide range of multicast applications and protocols such as local recovery for reliable multicast, self organized transcoding, self organizing web caches, the optimal and dynamic placement of proxies, repeaters, designated receivers, recorders and so forth.
Designing Asynchronous Circuits in Gallium Arsenide
Authors: Jose A. Tierno
Venue:  (1993)

No abstract.
On the Parallelization of Electrodynamic Multilevel Fast Multipole Method on Distributed Memory Computers
Authors: Sanjay Velamparambil, Jiming Song, Weng Cho Chew
Venue: Proceedings of the 1999 International Workshop on Innovative Architecture (1999)

In recent years, the Multilevel Fast Multipole Method (MLFMA) [14, 17] has been developed into one of the most powerful techniques for accelerating the iterative solution of integral equations of electromagnetics. It has been shown that the MLFMA reduces the computational complexity of a matrix-vector multiply from O(N2) to O(N log N), where N is the number of unknowns. In an attempt to extend the range of problems that can be solved using this technique, we have recently developed an application independent, parallel MLFMA kernel, called ScaleME, for distributed memory computers using MPI.In this paper, we shall discuss the characteristic features which distinguishes it from its static counterpart, such as work required for each level, the size of multipole expansions and interpolation/filtering operations, and their influence in the parallel algorithm design. We shall follow it with a discussion of major issues in the parallelization, which are unique to the dynamic MLFMA, such as reducing the memory requirements for translation operators and the reduction of replicated geometric data structures.We shall also briefly discuss the load balancing strategies. Finally, we shall present some representative numerical results from some ScaleME accelerated electromagnetic scattering codes, including a simulation involving 4 million unknowns and that of the radar cross-section computation of a full scale air-craft on a Beowulf class cluster.
Talking about what we think we see: natural language processing for a real-time virtual environment
Authors: J. Gurney, E. Klipple, C. Voss
Venue: Proceedings of the 1996 IEEE International Joint Symposia on Intelligence and Systems (1996)

In this paper we discuss some aspects of our development of a natural language (NL) processing system to be used in a virtual reality (VR) environment. Our group is pursuing two lines of work: the Natural Language and Virtual Reality (NLVR) project and the natural language research program. The latter addresses basic research problems in NL processing and the former is an implementation project. The two are, in many ways, parallel and overlapping. The research generates hypotheses that we want to test and the NLVR testbed provides new problems for research.
Representation of Almost Constant Vectors
Authors: Jorgen Steensgaard-Madsen
Venue:  (1979)

An example in a recent report on the programming language Russell has illustrated difficulties related to user defined storage management. Here is demonstrated how the dynamic approach to encapsulation earlier proposed by the author provides means to solve the particular storage management problem. The method used is, however, easily generalized to other similar cases. In addition to the example a number of notational conveniences are introduced. One that allows abbreviated references to components of record-like structures is called controlled coercion. Another allows a function-like use of classes. Keywords: Classes, abstract data types, storage management, programming languages.
Technique of computing logic derivatives for MVL-functions
Authors: V. P. Shmerko, S. Yanushkevich, V. Levashenko, I. Bondar
Venue: Proceedings of the 26th International Symposium on Multiple-Valued Logic (1996)

A technique to compute logic derivatives of MVL-functions is considered based on four algorithms, two of them are new. At first these are symbolic and matrix algorithms to find logic derivatives with respect to variables, and, secondly, partial direct and inverse derivatives. The algorithms are compared by using an example of testing a MVL switching circuit. The matrix approach allows to extract the appropriatenesses of computing process and to come to some simple operators of logic processing truth vectors of MVL functions.
On-Demand Forecasting of Stock Prices Using a Real-Time Predictor
Authors: Yi-Fan Wang
Venue: IEEE Transactions on Knowledge and Data Engineering (2003)

This paper presents a fuzzy stochastic prediction method for real-time predicting of stock prices. A complete contrast to the crisp stochastic method, it requires a fuzzy linguistic summary approach to computing parameters. This approach, which is found to be better than the gray prediction method, can eliminate outliers and limit the data to a normal condition for prediction, with a comparatively very small deviation of 4.5 percent.