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open access

A fast portable implementation of the Secure Hash Algorithm, III.

Description: In 1992, NIST announced a proposed standard for a collision-free hash function. The algorithm for producing the hash value is known as the Secure Hash Algorithm (SHA), and the standard using the algorithm in known as the Secure Hash Standard (SHS). Later, an announcement was made that a scientist at NSA had discovered a weakness in the original algorithm. A revision to this standard was then announced as FIPS 180-1, and includes a slight change to the algorithm that eliminates the weakness. Thi… more
Date: October 1, 1992
Creator: McCurley, Kevin S.
Partner: UNT Libraries Government Documents Department
open access

Compact Graph Representations and Parallel Connectivity Algorithms for Massive Dynamic Network Analysis

Description: Graph-theoretic abstractions are extensively used to analyze massive data sets. Temporal data streams from socioeconomic interactions, social networking web sites, communication traffic, and scientific computing can be intuitively modeled as graphs. We present the first study of novel high-performance combinatorial techniques for analyzing large-scale information networks, encapsulating dynamic interaction data in the order of billions of entities. We present new data structures to represent dy… more
Date: February 15, 2009
Creator: Madduri, Kamesh & Bader, David A.
Partner: UNT Libraries Government Documents Department
open access

Influence of machine organization on algorithms

Description: A comparative analysis of the CDC STAR-100 and the ILLIAC IV for a given code is given. A large two-dimensional Lagrangian hydrodynamic model for the STAR-100 computer was programmed. Some theoretical considerations concerning execution rates are Presented. Some examples are given of where these theoretical considerations were important considerations in the design of the algorithms. Finally, several observations and opinions, many of which may be controversial but which should be considered by… more
Date: May 1, 1973
Creator: Owens, J.L.
Partner: UNT Libraries Government Documents Department
open access

Efficient Parallel Algorithms and Data Structures Related to Trees

Description: The main contribution of this dissertation proposes a new paradigm, called the parentheses matching paradigm. It claims that this paradigm is well suited for designing efficient parallel algorithms for a broad class of nonnumeric problems. To demonstrate its applicability, we present three cost-optimal parallel algorithms for breadth-first traversal of general trees, sorting a special class of integers, and coloring an interval graph with the minimum number of colors.
Date: December 1991
Creator: Chen, Calvin Ching-Yuen
Partner: UNT Libraries
open access

Performance Study of Concurrent Search Trees and Hash Algorithms on Multiprocessors Systems

Description: This study examines the performance of concurrent algorithms for B-trees and linear hashing. B-trees are widely used as an access method for large, single key, database files, stored in lexicographic order on secondary storage devices. Linear hashing is a fast and reliable hash algorithm, suitable for accessing records stored unordered in buckets. This dissertation presents performance results on implementations of concurrent Bunk-tree and linear hashing algorithms, using lock-based, partitione… more
Date: May 1996
Creator: Demuynck, Marie-Anne
Partner: UNT Libraries
open access

High-performance combinatorial algorithms

Description: Combinatorial algorithms have long played an important role in many applications of scientific computing such as sparse matrix computations and parallel computing. The growing importance of combinatorial algorithms in emerging applications like computational biology and scientific data mining calls for development of a high performance library for combinatorial algorithms. Building such a library requires a new structure for combinatorial algorithms research that enables fast implementation of … more
Date: October 31, 2003
Creator: Pinar, Ali
Partner: UNT Libraries Government Documents Department
open access

Formulas for robust, one-pass parallel computation of covariances and arbitrary-order statistical moments.

Description: We present a formula for the pairwise update of arbitrary-order centered statistical moments. This formula is of particular interest to compute such moments in parallel for large-scale, distributed data sets. As a corollary, we indicate a specialization of this formula for incremental updates, of particular interest to streaming implementations. Finally, we provide pairwise and incremental update formulas for the covariance. Centered statistical moments are one of the most widely used tools in … more
Date: September 1, 2008
Creator: Pebay, Philippe Pierre
Partner: UNT Libraries Government Documents Department
open access

Autonomous Rule Creation for Intrusion Detection

Description: Many computational intelligence techniques for anomaly based network intrusion detection can be found in literature. Translating a newly discovered intrusion recognition criteria into a distributable rule can be a human intensive effort. This paper explores a multi-modal genetic algorithm solution for autonomous rule creation. This algorithm focuses on the process of creating rules once an intrusion has been identified, rather than the evolution of rules to provide a solution for intrusion dete… more
Date: April 1, 2011
Creator: Vollmer, Todd; Alves-Foss, Jim & Manic, Milos
Partner: UNT Libraries Government Documents Department
open access

A divide-and-conquer algorithm for identifying strongly connectedcomponents

Description: Strongly connected components of a directed graph can be found in an optimal linear time, by algorithms based on depth first search. Unfortunately, depth first search is difficult to parallelize. We describe two divide--and--conquer algorithms for this problem that have significantly greater potential for parallelization. We show the expected serial runtime of our simpler algorithm to be O(m log n), for a graph with n vertices and m edges. We then show that the second algorithm has O(mlog n) wo… more
Date: March 27, 2003
Creator: Coppersmith, Don; Fleischer, Lisa; Hendrickson, Bruce & Pinar, Ali
Partner: UNT Libraries Government Documents Department
open access

A Faster Parallel Algorithm and Efficient Multithreaded Implementations for Evaluating Betweenness Centrality on Massive Datasets

Description: We present a new lock-free parallel algorithm for computing betweenness centralityof massive small-world networks. With minor changes to the data structures, ouralgorithm also achieves better spatial cache locality compared to previous approaches. Betweenness centrality is a key algorithm kernel in HPCS SSCA#2, a benchmark extensively used to evaluate the performance of emerging high-performance computing architectures for graph-theoretic computations. We design optimized implementations of bet… more
Date: February 15, 2009
Creator: Madduri, Kamesh; Ediger, David; Jiang, Karl; Bader, David A. & Chavarria-Miranda, Daniel
Partner: UNT Libraries Government Documents Department
open access

Radiation transport algorithms on trans-petaflops supercomputers of different architectures.

Description: We seek to understand which supercomputer architecture will be best for supercomputers at the Petaflops scale and beyond. The process we use is to predict the cost and performance of several leading architectures at various years in the future. The basis for predicting the future is an expanded version of Moore's Law called the International Technology Roadmap for Semiconductors (ITRS). We abstract leading supercomputer architectures into chips connected by wires, where the chips and wires have… more
Date: August 1, 2003
Creator: Christopher, Thomas Woods
Partner: UNT Libraries Government Documents Department
open access

The SANDmath package.

Description: This is a basic documentation explaining how to use the SANDmath macros with a LATEX 2{var_epsilon} document pertaining to the SANDreport class.
Date: August 1, 2004
Creator: PÔebay, Philippe Pierre
Partner: UNT Libraries Government Documents Department
open access

CSCAPES Institute

Description: We report on the progress made by researchers of the CSCAPES Institute at Old Dominion University for the years 2007 and 2008 in the areas of research, software creation, education and training, and outreach activities.
Date: October 26, 2008
Creator: Pothen, Alex
Partner: UNT Libraries Government Documents Department
open access

Scalable fault tolerant algorithms for linear-scaling coupled-cluster electronic structure methods.

Description: By means of coupled-cluster theory, molecular properties can be computed with an accuracy often exceeding that of experiment. The high-degree polynomial scaling of the coupled-cluster method, however, remains a major obstacle in the accurate theoretical treatment of mainstream chemical problems, despite tremendous progress in computer architectures. Although it has long been recognized that this super-linear scaling is non-physical, the development of efficient reduced-scaling algorithms for ma… more
Date: October 1, 2004
Creator: Leininger, Matthew L.; Nielsen, Ida Marie B. & Janssen, Curtis L.
Partner: UNT Libraries Government Documents Department
open access

A generating set direct search augmented Lagrangian algorithm for optimization with a combination of general and linear constraints.

Description: We consider the solution of nonlinear programs in the case where derivatives of the objective function and nonlinear constraints are unavailable. To solve such problems, we propose an adaptation of a method due to Conn, Gould, Sartenaer, and Toint that proceeds by approximately minimizing a succession of linearly constrained augmented Lagrangians. Our modification is to use a derivative-free generating set direct search algorithm to solve the linearly constrained subproblems. The stopping crite… more
Date: August 1, 2006
Creator: Lewis, Robert Michael (College of William and Mary, Williamsburg, VA); Torczon, Virginia Joanne (College of William and Mary, Williamsburg, VA) & Kolda, Tamara Gibson
Partner: UNT Libraries Government Documents Department
open access

Study of Parallel Algorithms Related to Subsequence Problems on the Sequent Multiprocessor System

Description: The primary purpose of this work is to study, implement and analyze the performance of parallel algorithms related to subsequence problems. The problems include string to string correction problem, to determine the longest common subsequence problem and solving the sum-range-product, 1 —D pattern matching, longest non-decreasing (non-increasing) (LNS) and maximum positive subsequence (MPS) problems. The work also includes studying the techniques and issues involved in developing parallel applic… more
Date: August 1994
Creator: Pothuru, Surendra
Partner: UNT Libraries
open access

PRAM C:a new programming environment for fine-grain and coarse-grain parallelism.

Description: In the search for ''good'' parallel programming environments for Sandia's current and future parallel architectures, they revisit a long-standing open question. Can the PRAM parallel algorithms designed by theoretical computer scientists over the last two decades be implemented efficiently? This open question has co-existed with ongoing efforts in the HPC community to develop practical parallel programming models that can simultaneously provide ease of use, expressiveness, performance, and scal… more
Date: November 1, 2004
Creator: Brown, Jonathan Leighton & Wen, Zhaofang.
Partner: UNT Libraries Government Documents Department
open access

A first prototype of PyACTS

Description: The ACTS Collection is a set of software tools that help developers or programmers write high performance parallel codes for their scientific applications. PyACTS is a Python-based interface to some of the tools in the ACTS Collection. The main purpose of developing PyACTS is to provide a uniform easy-to-use external interface to existing ACTS tools,and support ACTS users to rapidly prototype their codes with the tools. In particular, for users who are new to ACTS, they will find PyACTS helpful… more
Date: August 31, 2003
Creator: Kang, Ning & Drummond, Leroy A.
Partner: UNT Libraries Government Documents Department
open access

Modeling Personalized Email Prioritization: Classification-based and Regression-based Approaches

Description: Email overload, even after spam filtering, presents a serious productivity challenge for busy professionals and executives. One solution is automated prioritization of incoming emails to ensure the most important are read and processed quickly, while others are processed later as/if time permits in declining priority levels. This paper presents a study of machine learning approaches to email prioritization into discrete levels, comparing ordinal regression versus classier cascades. Given the or… more
Date: October 24, 2011
Creator: Yoo, S.; Yang, Y. & Carbonell, J.
Partner: UNT Libraries Government Documents Department
open access

Community Petascale Project for Accelerator Science and Simulation

Description: The UCLA Plasma Simulation Group is a major partner of the "Community Petascale Project for Accelerator Science and Simulation. This is the final technical report. We include an overall summary, a list of publications and individual progress reports for each years. During the past five years we have made tremendous progress in enhancing the capabilities of OSIRIS and QuickPIC, in developing new algorithms and data structures for PIC codes to run on GPUS and many future core architectures, and i… more
Date: February 1, 2013
Creator: Mori, Warren B.
Partner: UNT Libraries Government Documents Department
open access

Intrinsic and Extrinsic Adaptation in a Simulated Combat Environment

Description: Genetic algorithm and artificial life techniques are applied to the development of challenging and interesting opponents in a combat-based computer game. Computer simulations are carried out against an idealized human player to gather data on the effectiveness of the computer generated opponents.
Date: May 1995
Creator: Dombrowsky, Steven P. (Steven Paul)
Partner: UNT Libraries
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