ppxscal/embedding_network huggingface dataset:
Comparing the Communication Performance and Scalability of a Linux and an NT Cluster of PCs, a Cray Origin 2000, an IBM SP and a Cray T3E-600
Authors: Glenn R. Luecke, Bruno Raffin, James J. Coyle
Venue: Proceedings of the 1st IEEE Computer Society International Workshop on Cluster Computing (1999)

This paper presents scalability and communication performance results for a cluster of PCs running Linux with the GM communication library, a cluster of PCs running Windows NT with the HPVM communication library, a Cray T3E-600, an IBM SP and a Cray Origin 2000. Both PC clusters were using a Myrinet network.Six communication tests using MPI routines were run for a variety of message sizes and numbers of processors. The tests were chosen to represent commonly-used communication patterns with low contention (a ping-pong between processors, a right shift, a binary tree broadcast and a synchronization barrier) to communication patterns with high contention (a naïve broadcast and an all-to-all).For most of the tests the T3E provides the best performance and scalability. For an 8 byte message the NT cluster performs about the same as the T3E for most of the tests. For all the tests but one, the T3E, the Origin and the SP outperform the two clusters for the largest message size (10 Kbytes or 1 Mbyte).
3D Articulated Models and Multi-View Tracking with Silhouettes
Authors: Quentin Delamarre, Olivier Faugeras
Venue: Proceedings of the International Conference on Computer Vision-Volume 2 - Volume 2 (1999)

We propose a method to estimate the motion of a person filmed by two or more fixed cameras. The novelty of our technique is its ability to cope with fast movements, self-occlusions and noisy images. Our algorithms are based on the latest works on calibration and image segmentation developed in our lab. We compare the projections of a 3D model of a person on the images to the detected silhouettes of the person, and create forces that will move the 3D model towards the final estimation of the real pose. We developed a fast algorithm that computes the motion of the articulated 3D model. We show that our results are good, even if the cameras are not synchronized.
Design of a Policy-Driven Middleware for Secure Distributed Collaboration
Authors: Anand R. Tripathi, Tanvir Ahmed, Richa Kumar, Shremattie Jaman
Venue: Proceedings of the 22 nd International Conference on Distributed Computing Systems (ICDCS'02) (2002)

We present here the execution model of a policy-driven middleware for building secure distributed collaboration systems from their high level specifications. Our specification model supports nested collaboration activities, and uses role-based security policies and event count based coordination specification. From the specifications of a collaboration environment, appropriate policy modules are derived for enforcing security and coordination requirements. A policy-driven distributed middleware provides services to the users to join roles in an activity, perform role specific operations, or create new activities. We describe here the design challenges for the middleware and present the run-time structures and protocols supported by it for creating activities, roles, and objects.
A Characterization of Communication Patterns in Isis Distributed Applications
Authors: A M Dietz, Carla Ellis
Venue:  (1995)

This study examines which high level language constructs application programmers choose to use in the design of distributed applications, and what communication patterns result from their use. This knowledge of the user workload is valuable to system designers in optimizing support for heavily used constructs and common communication patterns. We studied sophisticated production programs written using the Isis Distributed Toolkit. We traced messages at the application level rather than packets at the network level, thus capturing the characteristics of the communication patterns in a manner somewhat independent of network architectural features such as buffering and fragmentation. We ask these questions: \begin{itemize} \item Which high level programming constructs in Isis are used? RPCs? Multicasts? Process Groups? \item Do application level messages exhibit the same arrival locality characteristics as network packets? \item What characterizes the message traffic? \end{itemize} We found that the use of RPC-style constructs was light, multicast use was heavy (28% of messages), and process groups were used sparingly and had stable membership. Message arrival locality was similar to that reported in network traffic with an overall 45% of messages showing persistence (a message arriving from the same source process as the previous message). Messages ranged in size from 64 bytes to 12 kbytes with some very large bursts of small and medium size (less than 512 bytes) messages. Finally, we suggest performance techniques that can take advantage of the observed communication characteristics in future designs.
Advanced compilation techniques used in PORT system
Venue: Proceedings of the 1996 International Symposium on Parallel Architectures, Algorithms and Networks (1996)

Compilers perform interprocedural parallelization and optimization become an essential component of modern high performance computer systems. A compiler system that is called PORT is presented in this paper. Its important features, such as flow analysis, data dependence analysis and visualization tools are addressed.
An Efficient Parallel Algorithm for Shortest Paths in Planar Layered Digraphs
Authors: Sairam Subramanian, Robert Tamassia, Scott J Vitter
Venue:  (1993)

Computing shortest paths in a directed graph has received considerable attention in the sequential RAM model of computation. However, developing a polylog-time parallel algorithm that is close to the sequential optimal in terms of the total work done remains an elusive goal. We present a first step in this direction by giving efficient parallel algorithms for shortest paths in planar layered digraphs. We show that these graphs admit special kinds of separators called {\em one-way} separators which allow the paths in the graph to cross it only once. We use these separators to give divide and conquer solutions to the problem of finding the shortest paths between any two vertices. We first give a simple algorithm that works in the CREW model and computes the shortest path between any two vertices in an $n$-node planar layered digraph in time $O(\log^3 n)$ using $n/ \log n$ processors. A CRCW version of this algorithm runs in time $O(\log^2 n \log \log n)$ and uses $n/ \log \log n$ processors. We then use results of Aggarwal and Park [1] and Atallah [4] to improve the time bound to $O(\log^2 n)$ in the CREW model and $O(\log n \log \log n)$ in the CRCW model. The processor bounds still remain as $n/ \log n$ for the CREW model and $n/ \log \log n$ for the CRCW model.
Numerical analysis of fatigue damage evolution in composite pipe joints
Authors: Ł. Figiel, M. M. Kamiński
Venue: Proceedings of the sixth conference on Computational structures technology (2002)

The main goal of this paper is to present computational analysis of damage evolution in the adhesive joint connecting composite pipes subjected to tension with the constant amplitude. This approach uses the average shear stress criterion for defect propagation within adhesive layer and applies the continuum damage mechanics concept to continuum crack-like damage representation in terms of the finite element stiffness as a damage measure. Numerical studies are performed using the commercial Finite Element Method displacement-based program ANSYS using its special purpose finite element birth and death option. The prediction of composite pipe joint life is described in terms of defect growth rate as a function of load cycles number. Finally, a relation between the mean applied stress and the crack-like defect growth rate is obtained from computational simulation.
MetaJava: an efficient run-time meta architecture for Java/sup TM/
Authors: J. Kleinoder, M. Golm
Venue: Proceedings of the 5th International Workshop on Object Orientation in Operating Systems (IWOOOS '96) (1996)

Adaptability to special requirements of applications is a crucial concern of modern operating system architectures. Reflection and meta objects are means to achieve this adaptability. We report on ideas and experience we obtained while extending the run-time system of the object-oriented language Java with reflective capabilities. We explain our model of an object-oriented architecture that allows flexible and selective attachment of reflective properties to objects. We show how reflection can be obtained with minimal changes to the existing system and how the penalty in run-time performance can be minimized. Our architecture is not limited to special application domains like distributed or concurrent computing but can also be used to support different security policies, just-in-time compilation, location control of mobile objects, etc. As an example, a remote method invocation mechanism is described to demonstrate how the Java programming model can be enhanced using our meta architecture.
A comparison of the Sherali-Adams, Lov\\\\341sz-Schrijver and Lasserre relaxations for 0-1 programming
Authors: Monique Laurent
Venue:  (2001)

Sherali and Adams [SA90], Lov\''asz and Schrijver [LS91] and, recently, Lasserre [Las01b] have proposed lift and project methods for constructing hierarchies of successive linear or semidefinite relaxations of a $0-1$ polytope $P\subseteq \oR^n$ converging to $P$ in $n$ steps. Lasserre''s approach uses results about representations of positive polynomials as sums of squares and the dual theory of moments. We present the three methods in a common elementary framework and show that the Lasserre construction provides the tightest relaxations of $P$. As an application this gives a direct simple proof for the convergence of the Lasserre''s hierarchy. We describe applications to the stable set polytope and to the cut polytope.
A Performance Evaluation of List Scheduling Heuristics for Task Graphs without Communication Costs
Authors: Janez Brest, Viljem Zumer
Venue: Proceedings of the 2000 International Workshop on Parallel Processing (2000)

In this paper, we propose three new static scheduling algorithms for allocating task graphs without communication costs to fully connected multiprocessors. Proposed algorithms, called MCP/ABS, MCP/CLR, and MCP/CLRR, are based on the well known MCP algorithm, and all of them have the same complexity of O(v2 log v), where v is the number of nodes in the task graph. A global comparison of proposed algorithms with three recently reported scheduling algorithms is carried out. The proposed algorithms generate similar or even better solutions than the previous algorithms in terms of the completion times of resulting schedules using a Prototype Standard Task Graph Set.
Parallel Genetic Programming for Decision Tree Induction
Authors: Gianluigi Folino, Clara Pizzuti, Giandomenico Spezzano
Venue: Proceedings of the 13th IEEE International Conference on Tools with Artificial Intelligence (2001)

A parallel genetic programming approach to induce decision trees in large data sets is presented.A population of trees is evolved by employing the genetic operators and every individual is evaluated by using a fitness function based on the J-measure.The method is able to deal with large data sets since it uses a parallel implementation of genetic programming through the grid model and an out of core technique for those data sets that do not fit in main memory.Preliminary experiments on data sets from the UCI machine learning repository give good classification outcomes and assess the scalability of the method.
Computation of Spectral Information from Logic Netlists
Authors: Rolf Drechsler, Mitch Thornton
Venue: Proceedings of the 30th IEEE International Symposium on Multiple-Valued Logic (2000)

Spectral information can be used for many CAD system tasks including synthesis, verification and test vector generation. We analyze the problem of extracting spectral information from Boolean and multi-valued logic netlists. It is shown that spectral information may be calculated directly from output probabilities and a method for extracting output probabilities from general graphs is described. As a special case, we consider AND/OR graphs which are a data structure recently proposed as an alternative to decision diagrams. Experimental results are given to demonstrate the efficiency of our approach.
Linear algebra problems with APL2
Authors: Renzo L. Beltrame
Venue:  (1997)

We present a performance comparison of three IBM systems, main-frame, SP1, and SP2. Some data are added, which refer to enhanced nodes of SP2, and to two different nodes type and configuration. We choose for the comparison three linear algebra problems : the matrix product, the solution of a system of linear equations, and the calculation of eigenvalues and eigenvectors of a square matrix. The comparison was made by using the APL2 functions and operators that are implemented to solve linear algebra problems, because they are implemented as primitive or plugged functions. The data were collected from 1994, following the migrations of our our computer service. Since the comparison was made for offering to our users a first idea of the performance they could expect after the migration on the new architectures, the reported data concern a multiusers environment with a heavy load on each node. TEL:: +39 050 593 288 EMAIL:: Renzo.Beltrame@cnuce.cnr.it
Steiner Minimal Trees in Simple Polygons
Authors: Pawel Winter
Venue:  (1995)

An O(n log n) time and O(n) space algorithm for the Euclidean Steiner tree problem with four terminals in a simple polygon with n vertices is given. Its applicability to the problem of determining good quality solutions for any number of terminals is discussed.
Standard Handbook of Video and Television Engineering, 4 edition
Authors: Blair K. Benson
Venue:  (2003)

:Since its publication in February of 2000, the Standard Handbook of Video and Television Engineering has becomes its field's standard reference, the one book every engineer and technician in broadcasting needs to own. By carefully tracking the field's movement from monolithic broadcast stations into a complex web of smaller stations and video producers, this book has stayed relevant while its competition has fallen by the wayside.This new edition features over 50% new material, most crucially multiple chapters on video networking technologies, new digital television and data broadcast standards (for both the US and Europe), and updates on every aspect of video and broadcast equipment and protocols.
Locality Enhancement Of Imperfectly-nested Loop Nests
Authors: Nawaaz Ahmed
Venue:  (2000)

Most numerical applications using arrays require extensive program transformation in order to perform well on current machine architectures with deep memory hierarchies. These transformations ensure that an execution of the application exploits data-locality and uses the caches more effectively. The problem of exploiting data-locality is well understood only for a small class of applications -for programs in which all statements are present in the innermost loop of a loop-nest (called perfectly-nested loops). For such programs, statement instances can be mapped to an integer lattice (called the iteration space), and important transformations can be modelled as unimodular transformations of the iteration space. This framework has permitted the systematic application of transformations like loop-permutation, skewing and tiling in order to enhance locality in perfectly-nested loops. In dealing with programs that do not fall into this category, current compilers resort to ad-hoc techniques to find the right sequence of transformations. For some important benchmarks, no technique is known that will discover the right sequence of transformations. In my thesis, I propose a technique that extends the framework for perfectly-nested loops to general programs. The key idea is to embed the iteration space of every statement in the program into a special iteration space called the product space. The product space can be viewed as a perfectly-nested loop nest, so this embedding generalizes techniques like code sinking and loop fusion that are used in ad hoc ways in current compilers to produce perfectly-nested loops from imperfectly-nested ones. In contrast to these ad hoc techniques however, embeddings are chosen carefully to enhance locality. The product space is then transformed further using unimodular transformations, after which fully permutable loops are tiled, and code is generated. Code can also be generated to emulate block-recursive versions of the original program. I demonstrate the effectiveness of this approach for dense numerical linear algebra benchmarks, relaxation codes, and the tomcatv code from the SPECfp95 benchmark suite.
Evaluation of Loop Grouping Methods Based on Orthogonal Projection Spaces
Authors: Ioannis Drositis, Giorgos Goumas, Nectarios Koziris, Panayiotis Tsanakas, George Papakonstantinou
Venue: Proceedings of the Proceedings of the 2000 International Conference on Parallel Processing (2000)

This paper compares three similar loop-grouping methods. All methods are based on projecting the n-dimensional iteration space J n onto a k-dimensional one, called the projected space, using (n-k) linear independent vectors. The dimension k is selected differently in each method giving various results. The projected space is divided into discrete groups of related iterations, which are assigned to different processors. Two of the methods preserve optimal time completion, by scheduling loop iterations according to the hyperplane method. The theoretical analysis of the experimental results indicates the appropriate method, for specific iteration spaces and target architectures.
Topological design of loss-free switch-based LANs
Authors: B. Yener, Y. Ofek, M. Yung
Venue: Proceedings of the Fourteenth Annual Joint Conference of the IEEE Computer and Communication Societies (Vol. 1)-Volume - Volume 1 (1995)

The paper presents a new design methodology and tools to construct a switch-based LAN with (i) scalable throughput, (ii) no loss due to congestion, and (iii) two routing modes: FIFO or non-FIFO. More specifically, given a bounded degree (number of switch ports) at each node, the design is based on the construction of multiple virtual rings under the following constraints: (i) the virtual rings are pairwise edge-disjoint, and (ii) there is at least one virtual ring between any pair of nodes. The target topology is obtained from the edge union of the multiple virtual rings. The objectives of the above two constraints are (i) to ensure no loss due to congestion inside the network of bursty traffic sources, and (ii) to ensure convergence of packets/cells to their destinations. The virtual rings are constructed by a new methodology that employs combinatorial block designs together with a new algorithm for realizing any size networks. It is shown that the bound on the maximum route length, under the two constraints, is O(/spl radic/N) for an N-node network.
NAP: Practical Fault-Tolerance for Itinerant Computations
Authors: Dag Johansen, Keith Marzullo, Fred B. Schneider, Kjetil Jacobsen, Dmitrii Zagorodnov
Venue:  (1998)

NAP, a detection and recovery based scheme for implementing fault-tolerant itinerant computations, is presented. We give the semantics for the scheme and describe a protocol that implements NAP in Tacoma.
(Almost) No Cost Clock Synchronization
Authors: Ozalp Babaoglu, Rogerio Drummond
Venue:  (1986)

We show how synchronized clocks can be realized in a distributed system as a byproduct of a common communication paradigm where processors periodically perform broadcasts. Our approach decouples the precision concern-limiting how much correct clocks can differ from each other-and the accuracy concern-limiting how much any correct clock can differ from real time-of clock synchronization. Given a system that guarantees only precision, we develop a protocol whereby high accuracy can be achieved on demand. In this manner, the ``lazy'''' protocol we obtain incurs the cost of high accuracy only when needed while keeping the basic synchronization procedure extremely simple and cheap.
Parallel implementation of branch and bound algorithm for solving vehicle routing problem on NOWs
Authors: K. K. Lau, M. J. Kumar, N. R. Achuthan
Venue: Proceedings of the 1997 International Symposium on Parallel Architectures, Algorithms and Networks (1997)

This paper proposes a parallel branch and bound algorithm designed for solving the Vehicle Routing Problem (VRP) on NOWs (Networks of Workstations). Our objective is to minimize the execution time by considering parallel implementation to find an exact solution to the VRP in real time. Our experimental studies reveal that the proposed parallel branch and bound algorithm can achieve super-linear speedup for large problem sizes. Dynamic load balancing techniques for solving the VRP on NOWs are also discussed.
Hexagonal Raster for Computer Graphic
Venue: Proceedings of the International Conference on Information Visualisation (2000)

This article presents a new approach to representing a pixel in raster graphics. New technologies make this new approach possible. The author discusses issues concerning optic resolution of the human eye. Some technical solutions are proposed, which are currently being worked out and which can radically change the approach to raster picture. At creation, process of simulator and virtual reality quality of a picture is of great importance. Hitherto, prevailing solutions have many disadvantages.The solution suggested in this paper is based on the so-called H-pixel. Traditional pixel in raster graphics solutions is put into knots of grid plate. The suggested solution is based on a grid with regular hexagon as a main element. The paper includes analysis on how such a shape can help in fidelity of reproduction of set shapes. The algorithms for traditional pixel (Quadric pixel) have been prepared and checked.The presented approach to raster graphics can be used in systems where picture is created, similarly to typography, from a very good raster but in three (ROB) or four (CMYK) colors. Accepting H pixel will result in analysis ~f all algorithms of picture creation e.g. drawing a segment, circle etc. Such algorithms as raster picture compression or algorithms based on quadruple tree (covering invisible lines) will also need adaptation. Currently it is difficult to state to what extend this solution will be applied in the future but it is so likely and interesting that in the author's opinion it seems worth working on.
On-Line and Dynamic Shortest Paths Through Graph Decompositions
Authors: Hristo N. Djidjev, Grammati E. Pantziou, Christos D. Zaroliagis
Venue:  (1993)

We describe algorithms for finding shortest paths and distances in a planar digraph which exploit the particular topology of the input graph. An important feature of our algorithms is that they can work in a dynamic environment, where the cost of any edge can be changed or the edge can be deleted. For outerplanar digraphs, for instance, the data structures can be updated after any such change in only $O(\log n)$ time, where $n$ is the number of vertices of the digraph. We also describe the first parallel algorithms for solving the dynamic version of the shortest path problem. Our results can be extended to hold for digraphs of genus $o(n)$.