Digital Commons Network^™

Formal Methods For Portable, Scalable, Scheduling, Routing And Communication Protocol, Lenore M. R. Mullin, Scott A. Thibault, Daria R. Dooling, Erik A. Sandberg

Computer Science Technical Reports

The PRAM model has been shown to be an optimal design for emulating both loos and tightly coupled multiprocessors for unit time operations. Extensions to this design employ software pipelining on a network of homogeneous workstations. Partitioning array data structures and pipelining groups of partitions to processors can minimize latency and bottlenecking on distributted message passing multiprocessing architectures. Our previous paper developed a general message passing design that was conjectured to port to a CMS and scale to more processors connected via TCPIP protocol. This paper presents the results of of our ported and scaled designs. We have indeed developed …

Effective Data Parallel Computation Using The Psi Calculus, L. R. Mullin, M. A. Jenkins

Computer Science Technical Reports

No abstract provided.

Efficient Run-Time Assurance In Distributed Systems Through Selection Of Executable Assertions, Martina Schollmeyer, Bruce Mcmillin

Computer Science Technical Reports

Run-time assurance of a distributed system can be obtained by comparing, at run-time, the behavior of the program with the expected behavior described in the program's specification. Executable assertions, embedded into the program code, can determine when there are discrepancies, due to processor failures, between actual and expected behavior. Thus, there is no global monitoring scheme but processes will check each other.

A non-faulty process will always perform correct computation. It can detect errors in other processes after receiving information from them and checking it against expected values by using executable assertions. In order to efficiently check programs at run-time, …

Projective Plane Embeddings Of Polyhedral Pinched Maps, Adrian Riskin

Mathematics

We give various conditions on pinched-torus polyhedral maps which are necessary for their graphs to be embeddable in the projective plane. Our other main result is that even if the graph of a polyhedral map in the pinched torus is embeddable in a projective plane, the map induced by the embedding cannot be polyhedral, but must have all faces bounded by cycles. Finally, we give a class of examples of graphs which have polyhedral embeddings on the pinched torus and also on orientable surfaces of arbitrary high genus.

A Data Parallel Algorithm For Solving The Region Growing Problem On The Connection Machine, Nawal Copty, Sanjay Ranka, Geoffrey C. Fox, Ravi V. Shankar

College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects

Region growing is a general technique for image segmentation, where image characteristics are used to group adjacent pixels together to form regions. This paper presents a parallel algorithm for solving the region growing problem based on the split and merge approach, and uses it to test and compare various parallel architectures and programming models. The implementations were done on the Connection Machine, models CM-2 and CM-5, in the data parallel and message passing programming models. Randomization was introduced in breaking ties during merging to increase the degree of parallelism, and only one and two-dimensional arrays of data were used in …

The Complexity Of Local Stratification, Peter Cholak, Howard A. Blair

College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects

The class of locally stratified logic programs is shown to be Π 1 1-complete by the construction of a reducibility of the class of infinitely branching nondeterministic finite register machines.

Genetic Algorithms For Graph Partitioning And Incremental Graph Partitioning, Harpal Maini, Kishan Mehrotra, Chilukuri K. Mohan, Sanjay Ranka

College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects

Partitioning graphs into equally large groups of nodes, minimizing the number of edges between different groups, is an extremely important problem in parallel computing. This paper presents genetic algorithms for suboptimal graph partitioning, with new crossover operators (KNUX, DKNUX) that lead to orders of magnitude improvement over traditional genetic operators in solution quality and speed. Our method can improve on good solutions previously obtained by using other algorithms or graph theoretic heuristics in minimizing the total communication cost or the worst case cost of communication for a single processor. We also extend our algorithm to Incremental Graph Partitioning problems, in …

The Transportation Primitive, Ravi V. Shankar, Khaled A. Alsabti, Sanjay Ranka

College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects

This paper presents algorithms for implementing the transportation primitive on a distributed memory parallel architecture. The transportation primitive performs many-to-many personalized communication with bounded incoming and outgoing traffic. We present a two-stage deterministic algorithm that decomposes the communication with possibly high variance in message size into two communication stages with low message size variance. If the maximum outgoing or incoming traffic at any processor is t, transportation can be done in 2t¯ time (+ lower order terms) when t O(p 2 + pø=¯) (¯ is the inverse of the data transfer rate, ø is the startup overhead). If the maximum …

Parallel Incremental Graph Partitioning Using Linear Programming, Chao Wei Ou, Sanjay Ranka

College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects

Partitioning graphs into equally large groups of nodes while minimizing the number of edges between different groups is an extremely important problem in parallel computing. For instance, efficiently parallelizing several scientific and engineering applications requires the partitioning of data or tasks among processors such that the computational load on each node is roughly the same, while communication is minimized. Obtaining exact solutions is computationally intractable, since graph-partitioning is an NP-complete. For a large class of irregular and adaptive data parallel applications (such as adaptive meshes), the computational structure changes from one phase to another in an incremental fashion. In incremental …

Random Data Accesses On A Coarse-Grained Parallel Machine Ii. One-To-Many And Many-To-One Mappings, Ravi V. Shankar, Sanjay Ranka

College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects

This paper describes deterministic communication-efficient algorithms for performing random data accesses with hot spots on a coarse-grained parallel machine. The general random access read/write operations with hot spots can be completed in Clanip (+ lower order terms) time and is optimal and scalable provided n _> O(pa+p2r/l) (n is the number of elements distributed across p processors, r is the start-up overhead and 1/It is the data transfer rate). C is a small constant between 3 and 4 for the random access write operation, slightly higher for the random access read operation. Monotonic random access reads/writes can be completed with …

Optimal Processor Assignment For A Class Of Pipelined Computations, Alok N. Choudhary, Bhagirath Narahari, David Nicol, Rahul Simha

Electrical Engineering and Computer Science - All Scholarship

The availability of large scale multitasked parallel architectures introduces the following processor assignment problem: we are given a long sequence of data sets, each of which is to undergo processing by a collection of tasks whose inter-task data dependencies form a series-parallel partial order. Each individual task is potentially parallelizable, with a known experimentally determined execution signature. Recognizing that data sets can be pipelined through the task structure, the problem is to find a "good" assignment of processors to tasks. Two objectives interest us: minimal response time per data set given a throughput requirement, and maximal throughput given a response …

Design Issues For The Parallelization Of An Optimal Interpolation Algorithm, Gregor Von Laszewski, Mike Seablom, Miloje Makivic, Peter Lyster

Northeast Parallel Architecture Center

A regionalized optimal interpolation algorithm is currently used at the NASA Goddard Data Assimilation Office (DAO) for four dimensional data assimilation. Instead of using all observations regions are defined to approximate the solution. The sequential code for the regionalized optimal interpolation is very complex and in its current form unusable for MIMD machines. This paper describes the efforts at the DAO to parallelize the existing sequential algorithm. We outline three strategies transforming the sequential algorithm gradually to MIMD machines. A major requirement for the new parallel algorithm is the portability to as many MIMD machines as possible. Therefore, the parallel …

A Generalized Expression Optimization Hook For C++ On High-Performance Architectures, David J. Edelsohn

Northeast Parallel Architecture Center

C++ has gained broad acceptance as an object-oriented evolutionary extension to the C language, but it severely constrains methods for operating on class objects by forcing all data manipulation through an interface which assumes that all basic operations can be implemented as they are written: as unary or binary operators. C++ allows great flexibility in the creation of complex data structures which can perform the same functionality as built-in types of many other languages, but unfortunately it does not allow an equivalent level of flexibility so that operators acting on those data types can achieve the same level of efficiency …

On The Noninterpolation Of Polyhedral Maps, Adrian Riskin, D.W. Barnette

Mathematics

In this paper we show that if attention is restricted to polyhedral embeddings of graphs, no theorem analogous to the Duke interpolation theorem for 2-cell embeddings is true. We also give two interesting classes of graphs: (i) a class in which the members have polyhedral embeddings in the torus and also in orientable manifolds of arbitrarily high genus, (ii) and another in which the members have polyhedral embeddings in the projective plane and also in orientable and nonorientable manifolds of arbitrarily low Euler characteristic.

Fast Accurate Simulation Of Large Shared Memory Multiprocessors, Bob Boothe Phd

Faculty Publications

Fast computer simulation is an essential tool in the design of large parallel computers. We discuss the design and performance of our Fast Accurate Simulation Tool, FAST. We start by summarizing the tradeoffs made in the designs of this and other simulators. The key ideas used in this simulator involve execution driven simulation techniques that modify the object code of the application program being studied. This produces an augmented version of the code that is directly executed and performs much of the work of the simulation. We extend the previous work in execution driven simulation by introducing several new uses …

The Binational English & Spanish Telecommunications Network, Armando A. Arias Jr.

SSGS Faculty Publications and Presentations

BESTNET was established in the early 1980's, as an effort to link universities on both sides of the U.S.- Mexico border through microwave, satellite and cable television technologies. In the late 1980's BESTNET focused primarily on the development of asynchronous computer mediated learning and teaching in an internationally networked virtual environment. For the past six years (1990's) BESTNET has strengthened its binational ties and continued its "high tech" focus through the development of active or vibrant model technology which is assisting in the creation of an on-line binational university setting that is "borderless" (albeit, seamless to the user). Today, this …

Is Oberon As Simple As Possible?, Atanas Radenski

Mathematics, Physics, and Computer Science Faculty Books and Book Chapters

The design of the programming language Oberon was led by the quote by Albert Einstein: 'make it as simple as possible, but not simpler'. The objective of this paper is to analyze some design solutions and propose alternatives which could both simplify and strengthen the language without making it simpler than possible. The paper introduces one general concept, the module type, which can be used to represent records, modules, and eventually procedures. Type extension is redefined in terms of component nesting and incomplete designators. As a result, type extension supports multiple inheritance.

Performance Modeling Of Load Balancing Algorithms Using Neural Networks, Ishfaq Ahmad, Arif Ghafoor, Kishan Mehrotra, Chilukuri K. Mohan, Sanjay Ranka

College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects

This paper presents a new approach that uses neural networks to predict the performance of a number of dynamic decentralized load balancing strategies. A distributed multicomputer system using any distributed load balancing strategy is represented by a unified analytical queuing model. A large simulation data set is used to train a neural network using the back–propagation learning algorithm based on gradient descent. The performance model using the predicted data from the neural network produces the average response time of various load balancing algorithms under various system parameters. The validation and comparison with simulation data show that the neural network is …

Scheduling Of Unstructured Communication On The Intel Ipsc/860, Jhy-Chun Wang, Sanjay Ranka

College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects

In this paper we present several algorithms for decomposing all-to-many personalized communication into a set of disjoint partial permutations. These partial permutations avoid node contention as well as link contention. We discuss the theoretical complexity of these algorithms and study their effectiveness both from the view of static scheduling and from runtime scheduling. Experimental results for our algorithms are presented on the iPSC/860.

Tele-Assistance For Semi-Autonomous Robots, Erika Rogers, Robin R. Murphy

Computer Science and Software Engineering

This paper describes current work on a cooperative tele-assistance system for semi-autonomous robots. This system combines a robot architecture for limited autonomous perceptual and motor control with a knowledge-based operator assistant which provides strategic selection and enhancement of relevant data. The design of the system is presented, together with a number of exception-handling scenarios that were constructed as a result of experiments wit.h act.ual sensor data collected from two mobile robots.

Parameter Tuning For The Max Expert System, Christopher J. Merz, M. J. Pazzani

Computer Science Faculty Research & Creative Works

We investigate methods for tuning numeric parameters in Nynex MAX, a telephone trouble screening expert system. Steepest descent, hillclimbing, and simulated annealing parameter adjustment strategies are applied to the problems of maximizing classification accuracy and minimizing misclassification cost. For both of those optimization problems we evaluate each algorithm''s ability to tune initial parameters for several situations

A Fuzzy Logic-Based Foundation For Analyzing Imprecise Conflicting Requirements, J. Yen, Xiaoqing Frank Liu

Computer Science Faculty Research & Creative Works

Imprecise requirements are represented by the canonical form in test-score semantics. The concepts of feasibility, satisfiability, and specificity are formalized based on the fuzzy sets. The relationships between requirements are classified to be conflicting and cooperative. A feasible overall requirement can thus be formulated based on the tradeoff analysis of the conflicting requirements by using fuzzy multi-criteria optimization technique

Simple Genetic Algorithms With Linear Fitness, Michael D. Vose, Alden H. Wright

Computer Science Faculty Publications

A general form of stochastic search is described (random heuristic search), and some of its general properties are proved. This provides a framework in which the simple genetic algorithm (SGA) is a special case. The framework is used to illuminate relationships between seemingly different probabilistic perspectives of SGA behavior. Next, the SGA is formalized as an instance of random heuristic search. The formalization then used to show expected population fitness is a Lyapunov function in the infinite population model when mutation is zero and fitness is linear. In particular, the infinite population algorithm must converge, and average population …

The Multigraph Modeling Tool, Amy Apon, C A. Childers, W H. Hooper, K D. Gordon, L W. Dowdy

Publications

No abstract provided.

An Improved Characterization Of 1-Step Recoverable Embeddings: Rings In Hypercubes, Jun-Lin Liu, T.J. Sager, Bruce M. Mcmillin

Computer Science Faculty Research & Creative Works

An embedding is 1-step recoverable if any single fault occurs, the embedding can be reconfigured in one reconfiguration step to maintain the structure of the embedded graph. In this paper we present an efficient scheme to construct this type of 1-step recoverable ring embeddings in the hypercube. Our scheme will guarantee finding a 1-step recoverable embedding of a length-k (even) ring in a d-cube where 6 less than or equal to k less than or equal to (3/4)2/sup d/ and d greater than or equal to 3, provided such an embedding exists. Unlike previously proposed schemes, we solve the general …

Evolution In The Microprocessor Industry For Personal Computers: The Shift From Cisc Chips To Risc Chips, James Lamm

Honors Theses, 1963-2015

The thesis examines the semiconductor industry, specifically focusing on microprocessor manufacturers for the personal computer market. The current technology in the industry, CISC microprocessors, have reached a price/performance limit. The industry is turning to RISC microprocessors for improved speed at lower costs. Intel, the current industry leader, is being challenged by AMD and Cyrix, who manufacture clones of Intel¹s microprocessors. In addition, Motorola, another giant in the industry, has teamed up with Apple and IBM to challenge Intel¹s dominance of the industry. Motorola is attempting to set a new microprocessor standard based on a RISC microprocessor, the Power PC. Intel …

Genetic Algorithms For Soft Decision Decoding Of Linear Block Codes, Harpal Maini, Kishan Mehrotra, Chilukuri K. Mohan, Sanjay Ranka

College of Engineering and Computer Science - Former Departments, Centers, Institutes and Projects

Soft-decision decoding is an NP-hard problem of great interest to developers of communication systems. We show that this problem is equivalent to the problem of optimizing Walsh polynomials. We present genetic algorithms for soft-decision decoding of binary linear block codes and compare the performance with various other decoding algorithms including the currently developed A* algorithm. Simulation results show that our algorithms achieve bit-error-probabilities as low as 0:00183 for a [104; 52] code with a low signal-to-noise ratio of 2:5 dB, exploring only 22; 400 code words, whereas the search space contains 4:5 \Theta 10 15 codewords. We define a new …

Passion Runtime Library For Parallel I/O, Rajeev Thakur, Rajesh Bordawekar, Alok Choudhary, Ravi Ponnusamy

Electrical Engineering and Computer Science - All Scholarship

We are developing a compiler and runtime support system called PASSION: Parallel And Scalable Software for Input-Output. PASSION provides software support for I/O intensive out-of-core loosely synchronous problems. This paper gives an overview of the PASSION Runtime Library and describes two of the optimizations incorporated in it, namely Data Prefetching and Data Sieving. Performance improvements provided by these optimizations on the Intel Touchstone Delta are discussed, together with an out of -core Median Filtering application.

Logic Simulation Using An Asynchronous Parallel Discrete-Event Simulation Model On A Simd Machine, Sharad C. Seth, Lee Gowen, Matt Payne, Don Sylwester

School of Computing: Conference and Workshop Papers

The Chandy-Misra-Bryant (CMB) model has been applied to logic simulation of synchronous sequential circuits using a massively parallel SIMD computer, a CM-2 Connection Machine. Several methods of reducing message traffic in a logic simulation have been adapted to the SIMD architecture of the CM-2, with the result that each method of reducing message traffic actually decreases the speed of the simulation. This suggests that communication costs required to support logic simulation are small compared to the cost of deciding which messages need not be sent.

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 10, Number 1, January 1994, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

A fourteen page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.