Verification of Faulty Message Passing Systems with Continuous State Space in PVS

NASA Technical Reports Server (NTRS)

Pilotto, Concetta; White, Jerome

2010-01-01

We present a library of Prototype Verification System (PVS) meta-theories that verifies a class of distributed systems in which agent commu nication is through message-passing. The theoretic work, outlined in, consists of iterative schemes for solving systems of linear equations , such as message-passing extensions of the Gauss and Gauss-Seidel me thods. We briefly review that work and discuss the challenges in formally verifying it.

The serial message-passing schedule for LDPC decoding algorithms

NASA Astrophysics Data System (ADS)

Liu, Mingshan; Liu, Shanshan; Zhou, Yuan; Jiang, Xue

2015-12-01

The conventional message-passing schedule for LDPC decoding algorithms is the so-called flooding schedule. It has the disadvantage that the updated messages cannot be used until next iteration, thus reducing the convergence speed . In this case, the Layered Decoding algorithm (LBP) based on serial message-passing schedule is proposed. In this paper the decoding principle of LBP algorithm is briefly introduced, and then proposed its two improved algorithms, the grouped serial decoding algorithm (Grouped LBP) and the semi-serial decoding algorithm .They can improve LBP algorithm's decoding speed while maintaining a good decoding performance.

Mean-field message-passing equations in the Hopfield model and its generalizations

NASA Astrophysics Data System (ADS)

Mézard, Marc

2017-02-01

Motivated by recent progress in using restricted Boltzmann machines as preprocessing algorithms for deep neural network, we revisit the mean-field equations [belief-propagation and Thouless-Anderson Palmer (TAP) equations] in the best understood of such machines, namely the Hopfield model of neural networks, and we explicit how they can be used as iterative message-passing algorithms, providing a fast method to compute the local polarizations of neurons. In the "retrieval phase", where neurons polarize in the direction of one memorized pattern, we point out a major difference between the belief propagation and TAP equations: The set of belief propagation equations depends on the pattern which is retrieved, while one can use a unique set of TAP equations. This makes the latter method much better suited for applications in the learning process of restricted Boltzmann machines. In the case where the patterns memorized in the Hopfield model are not independent, but are correlated through a combinatorial structure, we show that the TAP equations have to be modified. This modification can be seen either as an alteration of the reaction term in TAP equations or, more interestingly, as the consequence of message passing on a graphical model with several hidden layers, where the number of hidden layers depends on the depth of the correlations in the memorized patterns. This layered structure is actually necessary when one deals with more general restricted Boltzmann machines.

Parallelization of the TRIGRS model for rainfall-induced landslides using the message passing interface

USGS Publications Warehouse

Alvioli, M.; Baum, R.L.

2016-01-01

We describe a parallel implementation of TRIGRS, the Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability Model for the timing and distribution of rainfall-induced shallow landslides. We have parallelized the four time-demanding execution modes of TRIGRS, namely both the saturated and unsaturated model with finite and infinite soil depth options, within the Message Passing Interface framework. In addition to new features of the code, we outline details of the parallel implementation and show the performance gain with respect to the serial code. Results are obtained both on commercial hardware and on a high-performance multi-node machine, showing the different limits of applicability of the new code. We also discuss the implications for the application of the model on large-scale areas and as a tool for real-time landslide hazard monitoring.

Users manual for the Chameleon parallel programming tools

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gropp, W.; Smith, B.

1993-06-01

Message passing is a common method for writing programs for distributed-memory parallel computers. Unfortunately, the lack of a standard for message passing has hampered the construction of portable and efficient parallel programs. In an attempt to remedy this problem, a number of groups have developed their own message-passing systems, each with its own strengths and weaknesses. Chameleon is a second-generation system of this type. Rather than replacing these existing systems, Chameleon is meant to supplement them by providing a uniform way to access many of these systems. Chameleon`s goals are to (a) be very lightweight (low over-head), (b) be highlymore » portable, and (c) help standardize program startup and the use of emerging message-passing operations such as collective operations on subsets of processors. Chameleon also provides a way to port programs written using PICL or Intel NX message passing to other systems, including collections of workstations. Chameleon is tracking the Message-Passing Interface (MPI) draft standard and will provide both an MPI implementation and an MPI transport layer. Chameleon provides support for heterogeneous computing by using p4 and PVM. Chameleon`s support for homogeneous computing includes the portable libraries p4, PICL, and PVM and vendor-specific implementation for Intel NX, IBM EUI (SP-1), and Thinking Machines CMMD (CM-5). Support for Ncube and PVM 3.x is also under development.« less

Combining Distributed and Shared Memory Models: Approach and Evolution of the Global Arrays Toolkit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nieplocha, Jarek; Harrison, Robert J.; Kumar, Mukul

2002-07-29

Both shared memory and distributed memory models have advantages and shortcomings. Shared memory model is much easier to use but it ignores data locality/placement. Given the hierarchical nature of the memory subsystems in the modern computers this characteristic might have a negative impact on performance and scalability. Various techniques, such as code restructuring to increase data reuse and introducing blocking in data accesses, can address the problem and yield performance competitive with message passing[Singh], however at the cost of compromising the ease of use feature. Distributed memory models such as message passing or one-sided communication offer performance and scalability butmore » they compromise the ease-of-use. In this context, the message-passing model is sometimes referred to as?assembly programming for the scientific computing?. The Global Arrays toolkit[GA1, GA2] attempts to offer the best features of both models. It implements a shared-memory programming model in which data locality is managed explicitly by the programmer. This management is achieved by explicit calls to functions that transfer data between a global address space (a distributed array) and local storage. In this respect, the GA model has similarities to the distributed shared-memory models that provide an explicit acquire/release protocol. However, the GA model acknowledges that remote data is slower to access than local data and allows data locality to be explicitly specified and hence managed. The GA model exposes to the programmer the hierarchical memory of modern high-performance computer systems, and by recognizing the communication overhead for remote data transfer, it promotes data reuse and locality of reference. This paper describes the characteristics of the Global Arrays programming model, capabilities of the toolkit, and discusses its evolution.« less

Efficient Implementation of Multigrid Solvers on Message-Passing Parrallel Systems

NASA Technical Reports Server (NTRS)

Lou, John

1994-01-01

We discuss our implementation strategies for finite difference multigrid partial differential equation (PDE) solvers on message-passing systems. Our target parallel architecture is Intel parallel computers: the Delta and Paragon system.

Passing messages between biological networks to refine predicted interactions.

PubMed

Glass, Kimberly; Huttenhower, Curtis; Quackenbush, John; Yuan, Guo-Cheng

2013-01-01

Regulatory network reconstruction is a fundamental problem in computational biology. There are significant limitations to such reconstruction using individual datasets, and increasingly people attempt to construct networks using multiple, independent datasets obtained from complementary sources, but methods for this integration are lacking. We developed PANDA (Passing Attributes between Networks for Data Assimilation), a message-passing model using multiple sources of information to predict regulatory relationships, and used it to integrate protein-protein interaction, gene expression, and sequence motif data to reconstruct genome-wide, condition-specific regulatory networks in yeast as a model. The resulting networks were not only more accurate than those produced using individual data sets and other existing methods, but they also captured information regarding specific biological mechanisms and pathways that were missed using other methodologies. PANDA is scalable to higher eukaryotes, applicable to specific tissue or cell type data and conceptually generalizable to include a variety of regulatory, interaction, expression, and other genome-scale data. An implementation of the PANDA algorithm is available at www.sourceforge.net/projects/panda-net.

Statistical mechanics of unsupervised feature learning in a restricted Boltzmann machine with binary synapses

NASA Astrophysics Data System (ADS)

Huang, Haiping

2017-05-01

Revealing hidden features in unlabeled data is called unsupervised feature learning, which plays an important role in pretraining a deep neural network. Here we provide a statistical mechanics analysis of the unsupervised learning in a restricted Boltzmann machine with binary synapses. A message passing equation to infer the hidden feature is derived, and furthermore, variants of this equation are analyzed. A statistical analysis by replica theory describes the thermodynamic properties of the model. Our analysis confirms an entropy crisis preceding the non-convergence of the message passing equation, suggesting a discontinuous phase transition as a key characteristic of the restricted Boltzmann machine. Continuous phase transition is also confirmed depending on the embedded feature strength in the data. The mean-field result under the replica symmetric assumption agrees with that obtained by running message passing algorithms on single instances of finite sizes. Interestingly, in an approximate Hopfield model, the entropy crisis is absent, and a continuous phase transition is observed instead. We also develop an iterative equation to infer the hyper-parameter (temperature) hidden in the data, which in physics corresponds to iteratively imposing Nishimori condition. Our study provides insights towards understanding the thermodynamic properties of the restricted Boltzmann machine learning, and moreover important theoretical basis to build simplified deep networks.

Parallelization of a hydrological model using the message passing interface

USGS Publications Warehouse

Wu, Yiping; Li, Tiejian; Sun, Liqun; Chen, Ji

2013-01-01

With the increasing knowledge about the natural processes, hydrological models such as the Soil and Water Assessment Tool (SWAT) are becoming larger and more complex with increasing computation time. Additionally, other procedures such as model calibration, which may require thousands of model iterations, can increase running time and thus further reduce rapid modeling and analysis. Using the widely-applied SWAT as an example, this study demonstrates how to parallelize a serial hydrological model in a Windows® environment using a parallel programing technology—Message Passing Interface (MPI). With a case study, we derived the optimal values for the two parameters (the number of processes and the corresponding percentage of work to be distributed to the master process) of the parallel SWAT (P-SWAT) on an ordinary personal computer and a work station. Our study indicates that model execution time can be reduced by 42%–70% (or a speedup of 1.74–3.36) using multiple processes (two to five) with a proper task-distribution scheme (between the master and slave processes). Although the computation time cost becomes lower with an increasing number of processes (from two to five), this enhancement becomes less due to the accompanied increase in demand for message passing procedures between the master and all slave processes. Our case study demonstrates that the P-SWAT with a five-process run may reach the maximum speedup, and the performance can be quite stable (fairly independent of a project size). Overall, the P-SWAT can help reduce the computation time substantially for an individual model run, manual and automatic calibration procedures, and optimization of best management practices. In particular, the parallelization method we used and the scheme for deriving the optimal parameters in this study can be valuable and easily applied to other hydrological or environmental models.

Gauge-free cluster variational method by maximal messages and moment matching.

PubMed

Domínguez, Eduardo; Lage-Castellanos, Alejandro; Mulet, Roberto; Ricci-Tersenghi, Federico

2017-04-01

We present an implementation of the cluster variational method (CVM) as a message passing algorithm. The kind of message passing algorithm used for CVM, usually named generalized belief propagation (GBP), is a generalization of the belief propagation algorithm in the same way that CVM is a generalization of the Bethe approximation for estimating the partition function. However, the connection between fixed points of GBP and the extremal points of the CVM free energy is usually not a one-to-one correspondence because of the existence of a gauge transformation involving the GBP messages. Our contribution is twofold. First, we propose a way of defining messages (fields) in a generic CVM approximation, such that messages arrive on a given region from all its ancestors, and not only from its direct parents, as in the standard parent-to-child GBP. We call this approach maximal messages. Second, we focus on the case of binary variables, reinterpreting the messages as fields enforcing the consistency between the moments of the local (marginal) probability distributions. We provide a precise rule to enforce all consistencies, avoiding any redundancy, that would otherwise lead to a gauge transformation on the messages. This moment matching method is gauge free, i.e., it guarantees that the resulting GBP is not gauge invariant. We apply our maximal messages and moment matching GBP to obtain an analytical expression for the critical temperature of the Ising model in general dimensions at the level of plaquette CVM. The values obtained outperform Bethe estimates, and are comparable with loop corrected belief propagation equations. The method allows for a straightforward generalization to disordered systems.

Gauge-free cluster variational method by maximal messages and moment matching

NASA Astrophysics Data System (ADS)

Domínguez, Eduardo; Lage-Castellanos, Alejandro; Mulet, Roberto; Ricci-Tersenghi, Federico

2017-04-01

We present an implementation of the cluster variational method (CVM) as a message passing algorithm. The kind of message passing algorithm used for CVM, usually named generalized belief propagation (GBP), is a generalization of the belief propagation algorithm in the same way that CVM is a generalization of the Bethe approximation for estimating the partition function. However, the connection between fixed points of GBP and the extremal points of the CVM free energy is usually not a one-to-one correspondence because of the existence of a gauge transformation involving the GBP messages. Our contribution is twofold. First, we propose a way of defining messages (fields) in a generic CVM approximation, such that messages arrive on a given region from all its ancestors, and not only from its direct parents, as in the standard parent-to-child GBP. We call this approach maximal messages. Second, we focus on the case of binary variables, reinterpreting the messages as fields enforcing the consistency between the moments of the local (marginal) probability distributions. We provide a precise rule to enforce all consistencies, avoiding any redundancy, that would otherwise lead to a gauge transformation on the messages. This moment matching method is gauge free, i.e., it guarantees that the resulting GBP is not gauge invariant. We apply our maximal messages and moment matching GBP to obtain an analytical expression for the critical temperature of the Ising model in general dimensions at the level of plaquette CVM. The values obtained outperform Bethe estimates, and are comparable with loop corrected belief propagation equations. The method allows for a straightforward generalization to disordered systems.

Performance Evaluation of Remote Memory Access (RMA) Programming on Shared Memory Parallel Computers

NASA Technical Reports Server (NTRS)

Jin, Hao-Qiang; Jost, Gabriele; Biegel, Bryan A. (Technical Monitor)

2002-01-01

The purpose of this study is to evaluate the feasibility of remote memory access (RMA) programming on shared memory parallel computers. We discuss different RMA based implementations of selected CFD application benchmark kernels and compare them to corresponding message passing based codes. For the message-passing implementation we use MPI point-to-point and global communication routines. For the RMA based approach we consider two different libraries supporting this programming model. One is a shared memory parallelization library (SMPlib) developed at NASA Ames, the other is the MPI-2 extensions to the MPI Standard. We give timing comparisons for the different implementation strategies and discuss the performance.

Message passing with parallel queue traversal

DOEpatents

Underwood, Keith D [Albuquerque, NM; Brightwell, Ronald B [Albuquerque, NM; Hemmert, K Scott [Albuquerque, NM

2012-05-01

In message passing implementations, associative matching structures are used to permit list entries to be searched in parallel fashion, thereby avoiding the delay of linear list traversal. List management capabilities are provided to support list entry turnover semantics and priority ordering semantics.

Foundations for a healthy future.

PubMed

Riley, R; Green, J; Willis, S; Soden, E; Rushby, C; Postle, D; Wakeling, S

1998-01-01

Health promotion activities with children and young people are important as they take messages about health seriously and can be influential in spreading messages about healthy living to their friends and families. Child health professionals have an important role to play in passing on messages of positive health to children and young people. Peer education is a useful way of passing on messages about health to young people. This article shares examples of three health promotion projects with children in a community trust, looking at asthma, sex education and testicular examination.

Passing Messages between Biological Networks to Refine Predicted Interactions

PubMed Central

Glass, Kimberly; Huttenhower, Curtis; Quackenbush, John; Yuan, Guo-Cheng

2013-01-01

Regulatory network reconstruction is a fundamental problem in computational biology. There are significant limitations to such reconstruction using individual datasets, and increasingly people attempt to construct networks using multiple, independent datasets obtained from complementary sources, but methods for this integration are lacking. We developed PANDA (Passing Attributes between Networks for Data Assimilation), a message-passing model using multiple sources of information to predict regulatory relationships, and used it to integrate protein-protein interaction, gene expression, and sequence motif data to reconstruct genome-wide, condition-specific regulatory networks in yeast as a model. The resulting networks were not only more accurate than those produced using individual data sets and other existing methods, but they also captured information regarding specific biological mechanisms and pathways that were missed using other methodologies. PANDA is scalable to higher eukaryotes, applicable to specific tissue or cell type data and conceptually generalizable to include a variety of regulatory, interaction, expression, and other genome-scale data. An implementation of the PANDA algorithm is available at www.sourceforge.net/projects/panda-net. PMID:23741402

Dispatching packets on a global combining network of a parallel computer

DOEpatents

Almasi, Gheorghe [Ardsley, NY; Archer, Charles J [Rochester, MN

2011-07-19

Methods, apparatus, and products are disclosed for dispatching packets on a global combining network of a parallel computer comprising a plurality of nodes connected for data communications using the network capable of performing collective operations and point to point operations that include: receiving, by an origin system messaging module on an origin node from an origin application messaging module on the origin node, a storage identifier and an operation identifier, the storage identifier specifying storage containing an application message for transmission to a target node, and the operation identifier specifying a message passing operation; packetizing, by the origin system messaging module, the application message into network packets for transmission to the target node, each network packet specifying the operation identifier and an operation type for the message passing operation specified by the operation identifier; and transmitting, by the origin system messaging module, the network packets to the target node.

Space Reclamation for Uncoordinated Checkpointing in Message-Passing Systems. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Wang, Yi-Min

1993-01-01

Checkpointing and rollback recovery are techniques that can provide efficient recovery from transient process failures. In a message-passing system, the rollback of a message sender may cause the rollback of the corresponding receiver, and the system needs to roll back to a consistent set of checkpoints called recovery line. If the processes are allowed to take uncoordinated checkpoints, the above rollback propagation may result in the domino effect which prevents recovery line progression. Traditionally, only obsolete checkpoints before the global recovery line can be discarded, and the necessary and sufficient condition for identifying all garbage checkpoints has remained an open problem. A necessary and sufficient condition for achieving optimal garbage collection is derived and it is proved that the number of useful checkpoints is bounded by N(N+1)/2, where N is the number of processes. The approach is based on the maximum-sized antichain model of consistent global checkpoints and the technique of recovery line transformation and decomposition. It is also shown that, for systems requiring message logging to record in-transit messages, the same approach can be used to achieve optimal message log reclamation. As a final topic, a unifying framework is described by considering checkpoint coordination and exploiting piecewise determinism as mechanisms for bounding rollback propagation, and the applicability of the optimal garbage collection algorithm to domino-free recovery protocols is demonstrated.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Painter, J.; McCormick, P.; Krogh, M.

This paper presents the ACL (Advanced Computing Lab) Message Passing Library. It is a high throughput, low latency communications library, based on Thinking Machines Corp.`s CMMD, upon which message passing applications can be built. The library has been implemented on the Cray T3D, Thinking Machines CM-5, SGI workstations, and on top of PVM.

Petascale computation performance of lightweight multiscale cardiac models using hybrid programming models.

PubMed

Pope, Bernard J; Fitch, Blake G; Pitman, Michael C; Rice, John J; Reumann, Matthias

2011-01-01

Future multiscale and multiphysics models must use the power of high performance computing (HPC) systems to enable research into human disease, translational medical science, and treatment. Previously we showed that computationally efficient multiscale models will require the use of sophisticated hybrid programming models, mixing distributed message passing processes (e.g. the message passing interface (MPI)) with multithreading (e.g. OpenMP, POSIX pthreads). The objective of this work is to compare the performance of such hybrid programming models when applied to the simulation of a lightweight multiscale cardiac model. Our results show that the hybrid models do not perform favourably when compared to an implementation using only MPI which is in contrast to our results using complex physiological models. Thus, with regards to lightweight multiscale cardiac models, the user may not need to increase programming complexity by using a hybrid programming approach. However, considering that model complexity will increase as well as the HPC system size in both node count and number of cores per node, it is still foreseeable that we will achieve faster than real time multiscale cardiac simulations on these systems using hybrid programming models.

High Performance Programming Using Explicit Shared Memory Model on Cray T3D1

NASA Technical Reports Server (NTRS)

Simon, Horst D.; Saini, Subhash; Grassi, Charles

1994-01-01

The Cray T3D system is the first-phase system in Cray Research, Inc.'s (CRI) three-phase massively parallel processing (MPP) program. This system features a heterogeneous architecture that closely couples DEC's Alpha microprocessors and CRI's parallel-vector technology, i.e., the Cray Y-MP and Cray C90. An overview of the Cray T3D hardware and available programming models is presented. Under Cray Research adaptive Fortran (CRAFT) model four programming methods (data parallel, work sharing, message-passing using PVM, and explicit shared memory model) are available to the users. However, at this time data parallel and work sharing programming models are not available to the user community. The differences between standard PVM and CRI's PVM are highlighted with performance measurements such as latencies and communication bandwidths. We have found that the performance of neither standard PVM nor CRI s PVM exploits the hardware capabilities of the T3D. The reasons for the bad performance of PVM as a native message-passing library are presented. This is illustrated by the performance of NAS Parallel Benchmarks (NPB) programmed in explicit shared memory model on Cray T3D. In general, the performance of standard PVM is about 4 to 5 times less than obtained by using explicit shared memory model. This degradation in performance is also seen on CM-5 where the performance of applications using native message-passing library CMMD on CM-5 is also about 4 to 5 times less than using data parallel methods. The issues involved (such as barriers, synchronization, invalidating data cache, aligning data cache etc.) while programming in explicit shared memory model are discussed. Comparative performance of NPB using explicit shared memory programming model on the Cray T3D and other highly parallel systems such as the TMC CM-5, Intel Paragon, Cray C90, IBM-SP1, etc. is presented.

DMA engine for repeating communication patterns

DOEpatents

Chen, Dong; Gara, Alan G.; Giampapa, Mark E.; Heidelberger, Philip; Steinmacher-Burow, Burkhard; Vranas, Pavlos

2010-09-21

A parallel computer system is constructed as a network of interconnected compute nodes to operate a global message-passing application for performing communications across the network. Each of the compute nodes includes one or more individual processors with memories which run local instances of the global message-passing application operating at each compute node to carry out local processing operations independent of processing operations carried out at other compute nodes. Each compute node also includes a DMA engine constructed to interact with the application via Injection FIFO Metadata describing multiple Injection FIFOs where each Injection FIFO may containing an arbitrary number of message descriptors in order to process messages with a fixed processing overhead irrespective of the number of message descriptors included in the Injection FIFO.

A Message Passing Approach to Side Chain Positioning with Applications in Protein Docking Refinement *

PubMed Central

Moghadasi, Mohammad; Kozakov, Dima; Mamonov, Artem B.; Vakili, Pirooz; Vajda, Sandor; Paschalidis, Ioannis Ch.

2013-01-01

We introduce a message-passing algorithm to solve the Side Chain Positioning (SCP) problem. SCP is a crucial component of protein docking refinement, which is a key step of an important class of problems in computational structural biology called protein docking. We model SCP as a combinatorial optimization problem and formulate it as a Maximum Weighted Independent Set (MWIS) problem. We then employ a modified and convergent belief-propagation algorithm to solve a relaxation of MWIS and develop randomized estimation heuristics that use the relaxed solution to obtain an effective MWIS feasible solution. Using a benchmark set of protein complexes we demonstrate that our approach leads to more accurate docking predictions compared to a baseline algorithm that does not solve the SCP. PMID:23515575

Parallel and fault-tolerant algorithms for hypercube multiprocessors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aykanat, C.

1988-01-01

Several techniques for increasing the performance of parallel algorithms on distributed-memory message-passing multi-processor systems are investigated. These techniques are effectively implemented for the parallelization of the Scaled Conjugate Gradient (SCG) algorithm on a hypercube connected message-passing multi-processor. Significant performance improvement is achieved by using these techniques. The SCG algorithm is used for the solution phase of an FE modeling system. Almost linear speed-up is achieved, and it is shown that hypercube topology is scalable for an FE class of problem. The SCG algorithm is also shown to be suitable for vectorization, and near supercomputer performance is achieved on a vectormore » hypercube multiprocessor by exploiting both parallelization and vectorization. Fault-tolerance issues for the parallel SCG algorithm and for the hypercube topology are also addressed.« less

Performance of hybrid programming models for multiscale cardiac simulations: preparing for petascale computation.

PubMed

Pope, Bernard J; Fitch, Blake G; Pitman, Michael C; Rice, John J; Reumann, Matthias

2011-10-01

Future multiscale and multiphysics models that support research into human disease, translational medical science, and treatment can utilize the power of high-performance computing (HPC) systems. We anticipate that computationally efficient multiscale models will require the use of sophisticated hybrid programming models, mixing distributed message-passing processes [e.g., the message-passing interface (MPI)] with multithreading (e.g., OpenMP, Pthreads). The objective of this study is to compare the performance of such hybrid programming models when applied to the simulation of a realistic physiological multiscale model of the heart. Our results show that the hybrid models perform favorably when compared to an implementation using only the MPI and, furthermore, that OpenMP in combination with the MPI provides a satisfactory compromise between performance and code complexity. Having the ability to use threads within MPI processes enables the sophisticated use of all processor cores for both computation and communication phases. Considering that HPC systems in 2012 will have two orders of magnitude more cores than what was used in this study, we believe that faster than real-time multiscale cardiac simulations can be achieved on these systems.

Performance Measurement, Visualization and Modeling of Parallel and Distributed Programs

NASA Technical Reports Server (NTRS)

Yan, Jerry C.; Sarukkai, Sekhar R.; Mehra, Pankaj; Lum, Henry, Jr. (Technical Monitor)

1994-01-01

This paper presents a methodology for debugging the performance of message-passing programs on both tightly coupled and loosely coupled distributed-memory machines. The AIMS (Automated Instrumentation and Monitoring System) toolkit, a suite of software tools for measurement and analysis of performance, is introduced and its application illustrated using several benchmark programs drawn from the field of computational fluid dynamics. AIMS includes (i) Xinstrument, a powerful source-code instrumentor, which supports both Fortran77 and C as well as a number of different message-passing libraries including Intel's NX Thinking Machines' CMMD, and PVM; (ii) Monitor, a library of timestamping and trace -collection routines that run on supercomputers (such as Intel's iPSC/860, Delta, and Paragon and Thinking Machines' CM5) as well as on networks of workstations (including Convex Cluster and SparcStations connected by a LAN); (iii) Visualization Kernel, a trace-animation facility that supports source-code clickback, simultaneous visualization of computation and communication patterns, as well as analysis of data movements; (iv) Statistics Kernel, an advanced profiling facility, that associates a variety of performance data with various syntactic components of a parallel program; (v) Index Kernel, a diagnostic tool that helps pinpoint performance bottlenecks through the use of abstract indices; (vi) Modeling Kernel, a facility for automated modeling of message-passing programs that supports both simulation -based and analytical approaches to performance prediction and scalability analysis; (vii) Intrusion Compensator, a utility for recovering true performance from observed performance by removing the overheads of monitoring and their effects on the communication pattern of the program; and (viii) Compatibility Tools, that convert AIMS-generated traces into formats used by other performance-visualization tools, such as ParaGraph, Pablo, and certain AVS/Explorer modules.

EMPIRE and pyenda: Two ensemble-based data assimilation systems written in Fortran and Python

NASA Astrophysics Data System (ADS)

Geppert, Gernot; Browne, Phil; van Leeuwen, Peter Jan; Merker, Claire

2017-04-01

We present and compare the features of two ensemble-based data assimilation frameworks, EMPIRE and pyenda. Both frameworks allow to couple models to the assimilation codes using the Message Passing Interface (MPI), leading to extremely efficient and fast coupling between models and the data-assimilation codes. The Fortran-based system EMPIRE (Employing Message Passing Interface for Researching Ensembles) is optimized for parallel, high-performance computing. It currently includes a suite of data assimilation algorithms including variants of the ensemble Kalman and several the particle filters. EMPIRE is targeted at models of all kinds of complexity and has been coupled to several geoscience models, eg. the Lorenz-63 model, a barotropic vorticity model, the general circulation model HadCM3, the ocean model NEMO, and the land-surface model JULES. The Python-based system pyenda (Python Ensemble Data Assimilation) allows Fortran- and Python-based models to be used for data assimilation. Models can be coupled either using MPI or by using a Python interface. Using Python allows quick prototyping and pyenda is aimed at small to medium scale models. pyenda currently includes variants of the ensemble Kalman filter and has been coupled to the Lorenz-63 model, an advection-based precipitation nowcasting scheme, and the dynamic global vegetation model JSBACH.

A message passing kernel for the hypercluster parallel processing test bed

NASA Technical Reports Server (NTRS)

Blech, Richard A.; Quealy, Angela; Cole, Gary L.

1989-01-01

A Message-Passing Kernel (MPK) for the Hypercluster parallel-processing test bed is described. The Hypercluster is being developed at the NASA Lewis Research Center to support investigations of parallel algorithms and architectures for computational fluid and structural mechanics applications. The Hypercluster resembles the hypercube architecture except that each node consists of multiple processors communicating through shared memory. The MPK efficiently routes information through the Hypercluster, using a message-passing protocol when necessary and faster shared-memory communication whenever possible. The MPK also interfaces all of the processors with the Hypercluster operating system (HYCLOPS), which runs on a Front-End Processor (FEP). This approach distributes many of the I/O tasks to the Hypercluster processors and eliminates the need for a separate I/O support program on the FEP.

A Model for Speedup of Parallel Programs

DTIC Science & Technology

1997-01-01

Sanjeev. K Setia . The interaction between mem- ory allocation and adaptive partitioning in message- passing multicomputers. In IPPS 󈨣 Workshop on Job...Scheduling Strategies for Parallel Processing, pages 89{99, 1995. [15] Sanjeev K. Setia and Satish K. Tripathi. A compar- ative analysis of static

Information Management and Learning in Computer Conferences: Coping with Irrelevant and Unconnected Messages.

ERIC Educational Resources Information Center

Schwan, Stephan; Straub, Daniela; Hesse, Friedrich W.

2002-01-01

Describes a study of computer conferencing where learners interacted over the course of four log-in sessions to acquire the knowledge sufficient to pass a learning test. Studied the number of messages irrelevant to the topic, explicit threading of messages, reading times of relevant messages, and learning outcomes. (LRW)

The Edge-Disjoint Path Problem on Random Graphs by Message-Passing.

PubMed

Altarelli, Fabrizio; Braunstein, Alfredo; Dall'Asta, Luca; De Bacco, Caterina; Franz, Silvio

2015-01-01

We present a message-passing algorithm to solve a series of edge-disjoint path problems on graphs based on the zero-temperature cavity equations. Edge-disjoint paths problems are important in the general context of routing, that can be defined by incorporating under a unique framework both traffic optimization and total path length minimization. The computation of the cavity equations can be performed efficiently by exploiting a mapping of a generalized edge-disjoint path problem on a star graph onto a weighted maximum matching problem. We perform extensive numerical simulations on random graphs of various types to test the performance both in terms of path length minimization and maximization of the number of accommodated paths. In addition, we test the performance on benchmark instances on various graphs by comparison with state-of-the-art algorithms and results found in the literature. Our message-passing algorithm always outperforms the others in terms of the number of accommodated paths when considering non trivial instances (otherwise it gives the same trivial results). Remarkably, the largest improvement in performance with respect to the other methods employed is found in the case of benchmarks with meshes, where the validity hypothesis behind message-passing is expected to worsen. In these cases, even though the exact message-passing equations do not converge, by introducing a reinforcement parameter to force convergence towards a sub optimal solution, we were able to always outperform the other algorithms with a peak of 27% performance improvement in terms of accommodated paths. On random graphs, we numerically observe two separated regimes: one in which all paths can be accommodated and one in which this is not possible. We also investigate the behavior of both the number of paths to be accommodated and their minimum total length.

The Edge-Disjoint Path Problem on Random Graphs by Message-Passing

PubMed Central

2015-01-01

We present a message-passing algorithm to solve a series of edge-disjoint path problems on graphs based on the zero-temperature cavity equations. Edge-disjoint paths problems are important in the general context of routing, that can be defined by incorporating under a unique framework both traffic optimization and total path length minimization. The computation of the cavity equations can be performed efficiently by exploiting a mapping of a generalized edge-disjoint path problem on a star graph onto a weighted maximum matching problem. We perform extensive numerical simulations on random graphs of various types to test the performance both in terms of path length minimization and maximization of the number of accommodated paths. In addition, we test the performance on benchmark instances on various graphs by comparison with state-of-the-art algorithms and results found in the literature. Our message-passing algorithm always outperforms the others in terms of the number of accommodated paths when considering non trivial instances (otherwise it gives the same trivial results). Remarkably, the largest improvement in performance with respect to the other methods employed is found in the case of benchmarks with meshes, where the validity hypothesis behind message-passing is expected to worsen. In these cases, even though the exact message-passing equations do not converge, by introducing a reinforcement parameter to force convergence towards a sub optimal solution, we were able to always outperform the other algorithms with a peak of 27% performance improvement in terms of accommodated paths. On random graphs, we numerically observe two separated regimes: one in which all paths can be accommodated and one in which this is not possible. We also investigate the behavior of both the number of paths to be accommodated and their minimum total length. PMID:26710102

Message passing with a limited number of DMA byte counters

DOEpatents

Blocksome, Michael [Rochester, MN; Chen, Dong [Croton on Hudson, NY; Giampapa, Mark E [Irvington, NY; Heidelberger, Philip [Cortlandt Manor, NY; Kumar, Sameer [White Plains, NY; Parker, Jeffrey J [Rochester, MN

2011-10-04

A method for passing messages in a parallel computer system constructed as a plurality of compute nodes interconnected as a network where each compute node includes a DMA engine but includes only a limited number of byte counters for tracking a number of bytes that are sent or received by the DMA engine, where the byte counters may be used in shared counter or exclusive counter modes of operation. The method includes using rendezvous protocol, a source compute node deterministically sending a request to send (RTS) message with a single RTS descriptor using an exclusive injection counter to track both the RTS message and message data to be sent in association with the RTS message, to a destination compute node such that the RTS descriptor indicates to the destination compute node that the message data will be adaptively routed to the destination node. Using one DMA FIFO at the source compute node, the RTS descriptors are maintained for rendezvous messages destined for the destination compute node to ensure proper message data ordering thereat. Using a reception counter at a DMA engine, the destination compute node tracks reception of the RTS and associated message data and sends a clear to send (CTS) message to the source node in a rendezvous protocol form of a remote get to accept the RTS message and message data and processing the remote get (CTS) by the source compute node DMA engine to provide the message data to be sent.

Extensions to the Parallel Real-Time Artificial Intelligence System (PRAIS) for fault-tolerant heterogeneous cycle-stealing reasoning

NASA Technical Reports Server (NTRS)

Goldstein, David

1991-01-01

Extensions to an architecture for real-time, distributed (parallel) knowledge-based systems called the Parallel Real-time Artificial Intelligence System (PRAIS) are discussed. PRAIS strives for transparently parallelizing production (rule-based) systems, even under real-time constraints. PRAIS accomplished these goals (presented at the first annual C Language Integrated Production System (CLIPS) conference) by incorporating a dynamic task scheduler, operating system extensions for fact handling, and message-passing among multiple copies of CLIPS executing on a virtual blackboard. This distributed knowledge-based system tool uses the portability of CLIPS and common message-passing protocols to operate over a heterogeneous network of processors. Results using the original PRAIS architecture over a network of Sun 3's, Sun 4's and VAX's are presented. Mechanisms using the producer-consumer model to extend the architecture for fault-tolerance and distributed truth maintenance initiation are also discussed.

Public-channel cryptography based on mutual chaos pass filters.

PubMed

Klein, Einat; Gross, Noam; Kopelowitz, Evi; Rosenbluh, Michael; Khaykovich, Lev; Kinzel, Wolfgang; Kanter, Ido

2006-10-01

We study the mutual coupling of chaotic lasers and observe both experimentally and in numeric simulations that there exists a regime of parameters for which two mutually coupled chaotic lasers establish isochronal synchronization, while a third laser coupled unidirectionally to one of the pair does not synchronize. We then propose a cryptographic scheme, based on the advantage of mutual coupling over unidirectional coupling, where all the parameters of the system are public knowledge. We numerically demonstrate that in such a scheme the two communicating lasers can add a message signal (compressed binary message) to the transmitted coupling signal and recover the message in both directions with high fidelity by using a mutual chaos pass filter procedure. An attacker, however, fails to recover an errorless message even if he amplifies the coupling signal.

An implementation and performance measurement of the progressive retry technique

NASA Technical Reports Server (NTRS)

Suri, Gaurav; Huang, Yennun; Wang, Yi-Min; Fuchs, W. Kent; Kintala, Chandra

1995-01-01

This paper describes a recovery technique called progressive retry for bypassing software faults in message-passing applications. The technique is implemented as reusable modules to provide application-level software fault tolerance. The paper describes the implementation of the technique and presents results from the application of progressive retry to two telecommunications systems. the results presented show that the technique is helpful in reducing the total recovery time for message-passing applications.

Belief propagation decoding of quantum channels by passing quantum messages

NASA Astrophysics Data System (ADS)

Renes, Joseph M.

2017-07-01

The belief propagation (BP) algorithm is a powerful tool in a wide range of disciplines from statistical physics to machine learning to computational biology, and is ubiquitous in decoding classical error-correcting codes. The algorithm works by passing messages between nodes of the factor graph associated with the code and enables efficient decoding of the channel, in some cases even up to the Shannon capacity. Here we construct the first BP algorithm which passes quantum messages on the factor graph and is capable of decoding the classical-quantum channel with pure state outputs. This gives explicit decoding circuits whose number of gates is quadratic in the code length. We also show that this decoder can be modified to work with polar codes for the pure state channel and as part of a decoder for transmitting quantum information over the amplitude damping channel. These represent the first explicit capacity-achieving decoders for non-Pauli channels.

LCAMP: Location Constrained Approximate Message Passing for Compressed Sensing MRI

PubMed Central

Sung, Kyunghyun; Daniel, Bruce L; Hargreaves, Brian A

2016-01-01

Iterative thresholding methods have been extensively studied as faster alternatives to convex optimization methods for solving large-sized problems in compressed sensing. A novel iterative thresholding method called LCAMP (Location Constrained Approximate Message Passing) is presented for reducing computational complexity and improving reconstruction accuracy when a nonzero location (or sparse support) constraint can be obtained from view shared images. LCAMP modifies the existing approximate message passing algorithm by replacing the thresholding stage with a location constraint, which avoids adjusting regularization parameters or thresholding levels. This work is first compared with other conventional reconstruction methods using random 1D signals and then applied to dynamic contrast-enhanced breast MRI to demonstrate the excellent reconstruction accuracy (less than 2% absolute difference) and low computation time (5 - 10 seconds using Matlab) with highly undersampled 3D data (244 × 128 × 48; overall reduction factor = 10). PMID:23042658

Efficient Tracing for On-the-Fly Space-Time Displays in a Debugger for Message Passing Programs

NASA Technical Reports Server (NTRS)

Hood, Robert; Matthews, Gregory

2001-01-01

In this work we describe the implementation of a practical mechanism for collecting and displaying trace information in a debugger for message passing programs. We introduce a trace format that is highly compressible while still providing information adequate for debugging purposes. We make the mechanism convenient for users to access by incorporating the trace collection in a set of wrappers for the MPI (message passing interface) communication library. We implement several debugger operations that use the trace display: consistent stoplines, undo, and rollback. They all are implemented using controlled replay, which executes at full speed in target processes until the appropriate position in the computation is reached. They provide convenient mechanisms for getting to places in the execution where the full power of a state-based debugger can be brought to bear on isolating communication errors.

Reducing Interprocessor Dependence in Recoverable Distributed Shared Memory

NASA Technical Reports Server (NTRS)

Janssens, Bob; Fuchs, W. Kent

1994-01-01

Checkpointing techniques in parallel systems use dependency tracking and/or message logging to ensure that a system rolls back to a consistent state. Traditional dependency tracking in distributed shared memory (DSM) systems is expensive because of high communication frequency. In this paper we show that, if designed correctly, a DSM system only needs to consider dependencies due to the transfer of blocks of data, resulting in reduced dependency tracking overhead and reduced potential for rollback propagation. We develop an ownership timestamp scheme to tolerate the loss of block state information and develop a passive server model of execution where interactions between processors are considered atomic. With our scheme, dependencies are significantly reduced compared to the traditional message-passing model.

Scalable Replay with Partial-Order Dependencies for Message-Logging Fault Tolerance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lifflander, Jonathan; Meneses, Esteban; Menon, Harshita

2014-09-22

Deterministic replay of a parallel application is commonly used for discovering bugs or to recover from a hard fault with message-logging fault tolerance. For message passing programs, a major source of overhead during forward execution is recording the order in which messages are sent and received. During replay, this ordering must be used to deterministically reproduce the execution. Previous work in replay algorithms often makes minimal assumptions about the programming model and application in order to maintain generality. However, in many cases, only a partial order must be recorded due to determinism intrinsic in the code, ordering constraints imposed bymore » the execution model, and events that are commutative (their relative execution order during replay does not need to be reproduced exactly). In this paper, we present a novel algebraic framework for reasoning about the minimum dependencies required to represent the partial order for different concurrent orderings and interleavings. By exploiting this theory, we improve on an existing scalable message-logging fault tolerance scheme. The improved scheme scales to 131,072 cores on an IBM BlueGene/P with up to 2x lower overhead than one that records a total order.« less

Strategies for Energy Efficient Resource Management of Hybrid Programming Models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Dong; Supinski, Bronis de; Schulz, Martin

2013-01-01

Many scientific applications are programmed using hybrid programming models that use both message-passing and shared-memory, due to the increasing prevalence of large-scale systems with multicore, multisocket nodes. Previous work has shown that energy efficiency can be improved using software-controlled execution schemes that consider both the programming model and the power-aware execution capabilities of the system. However, such approaches have focused on identifying optimal resource utilization for one programming model, either shared-memory or message-passing, in isolation. The potential solution space, thus the challenge, increases substantially when optimizing hybrid models since the possible resource configurations increase exponentially. Nonetheless, with the accelerating adoptionmore » of hybrid programming models, we increasingly need improved energy efficiency in hybrid parallel applications on large-scale systems. In this work, we present new software-controlled execution schemes that consider the effects of dynamic concurrency throttling (DCT) and dynamic voltage and frequency scaling (DVFS) in the context of hybrid programming models. Specifically, we present predictive models and novel algorithms based on statistical analysis that anticipate application power and time requirements under different concurrency and frequency configurations. We apply our models and methods to the NPB MZ benchmarks and selected applications from the ASC Sequoia codes. Overall, we achieve substantial energy savings (8.74% on average and up to 13.8%) with some performance gain (up to 7.5%) or negligible performance loss.« less

Parallel community climate model: Description and user`s guide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Drake, J.B.; Flanery, R.E.; Semeraro, B.D.

This report gives an overview of a parallel version of the NCAR Community Climate Model, CCM2, implemented for MIMD massively parallel computers using a message-passing programming paradigm. The parallel implementation was developed on an Intel iPSC/860 with 128 processors and on the Intel Delta with 512 processors, and the initial target platform for the production version of the code is the Intel Paragon with 2048 processors. Because the implementation uses a standard, portable message-passing libraries, the code has been easily ported to other multiprocessors supporting a message-passing programming paradigm. The parallelization strategy used is to decompose the problem domain intomore » geographical patches and assign each processor the computation associated with a distinct subset of the patches. With this decomposition, the physics calculations involve only grid points and data local to a processor and are performed in parallel. Using parallel algorithms developed for the semi-Lagrangian transport, the fast Fourier transform and the Legendre transform, both physics and dynamics are computed in parallel with minimal data movement and modest change to the original CCM2 source code. Sequential or parallel history tapes are written and input files (in history tape format) are read sequentially by the parallel code to promote compatibility with production use of the model on other computer systems. A validation exercise has been performed with the parallel code and is detailed along with some performance numbers on the Intel Paragon and the IBM SP2. A discussion of reproducibility of results is included. A user`s guide for the PCCM2 version 2.1 on the various parallel machines completes the report. Procedures for compilation, setup and execution are given. A discussion of code internals is included for those who may wish to modify and use the program in their own research.« less

CSlib, a library to couple codes via Client/Server messaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plimpton, Steve

The CSlib is a small, portable library which enables two (or more) independent simulation codes to be coupled, by exchanging messages with each other. Both codes link to the library when they are built, and can them communicate with each other as they run. The messages contain data or instructions that the two codes send back-and-forth to each other. The messaging can take place via files, sockets, or MPI. The latter is a standard distributed-memory message-passing library.

Design and Implementation of an Operations Module for the ARGOS paperless Ship System

DTIC Science & Technology

1989-06-01

A. OPERATIONS STACK SCRIPTS SCRIPTS FOR STACK: operations * BACKGROUND #1: Operations * on openStack hide message box show menuBar pass openStack end... openStack ** CARD #1, BUTTON #1: Up ***** on mouseUp visual effect zoom out go to card id 10931 of stack argos end mouseUp ** CARD #1, BUTTON #2...STACK SCRIPTS SCRIPTS FOR STACK: Reports ** BACKGROUND #1: Operations * on openStack hie message box show menuBar pass openStack end openStack ** CARD #1

Experiences Using OpenMP Based on Compiler Directed Software DSM on a PC Cluster

NASA Technical Reports Server (NTRS)

Hess, Matthias; Jost, Gabriele; Mueller, Matthias; Ruehle, Roland; Biegel, Bryan (Technical Monitor)

2002-01-01

In this work we report on our experiences running OpenMP (message passing) programs on a commodity cluster of PCs (personal computers) running a software distributed shared memory (DSM) system. We describe our test environment and report on the performance of a subset of the NAS (NASA Advanced Supercomputing) Parallel Benchmarks that have been automatically parallelized for OpenMP. We compare the performance of the OpenMP implementations with that of their message passing counterparts and discuss performance differences.

Charon Message-Passing Toolkit for Scientific Computations

NASA Technical Reports Server (NTRS)

VanderWijngaart, Rob F.; Yan, Jerry (Technical Monitor)

2000-01-01

Charon is a library, callable from C and Fortran, that aids the conversion of structured-grid legacy codes-such as those used in the numerical computation of fluid flows-into parallel, high- performance codes. Key are functions that define distributed arrays, that map between distributed and non-distributed arrays, and that allow easy specification of common communications on structured grids. The library is based on the widely accepted MPI message passing standard. We present an overview of the functionality of Charon, and some representative results.

Parallel Ray Tracing Using the Message Passing Interface

DTIC Science & Technology

2007-09-01

software is available for lens design and for general optical systems modeling. It tends to be designed to run on a single processor and can be very...Cameron, Senior Member, IEEE Abstract—Ray-tracing software is available for lens design and for general optical systems modeling. It tends to be designed to...National Aeronautics and Space Administration (NASA), optical ray tracing, parallel computing, parallel pro- cessing, prime numbers, ray tracing

Couriers in the Inca Empire: Getting Your Message Across. [Lesson Plan].

ERIC Educational Resources Information Center

2002

This lesson shows how the Inca communicated across the vast stretches of their mountain realm, the largest empire of the pre-industrial world. The lesson explains how couriers carried messages along mountain-ridge roads, up and down stone steps, and over chasm-spanning footbridges. It states that couriers could pass a message from Quito (Ecuador)…

Critical field-exponents for secure message-passing in modular networks

NASA Astrophysics Data System (ADS)

Shekhtman, Louis M.; Danziger, Michael M.; Bonamassa, Ivan; Buldyrev, Sergey V.; Caldarelli, Guido; Zlatić, Vinko; Havlin, Shlomo

2018-05-01

We study secure message-passing in the presence of multiple adversaries in modular networks. We assume a dominant fraction of nodes in each module have the same vulnerability, i.e., the same entity spying on them. We find both analytically and via simulations that the links between the modules (interlinks) have effects analogous to a magnetic field in a spin-system in that for any amount of interlinks the system no longer undergoes a phase transition. We then define the exponents δ, which relates the order parameter (the size of the giant secure component) at the critical point to the field strength (average number of interlinks per node), and γ, which describes the susceptibility near criticality. These are found to be δ = 2 and γ = 1 (with the scaling of the order parameter near the critical point given by β = 1). When two or more vulnerabilities are equally present in a module we find δ = 1 and γ = 0 (with β ≥ 2). Apart from defining a previously unidentified universality class, these exponents show that increasing connections between modules is more beneficial for security than increasing connections within modules. We also measure the correlation critical exponent ν, and the upper critical dimension d c , finding that ν {d}c=3 as for ordinary percolation, suggesting that for secure message-passing d c = 6. These results provide an interesting analogy between secure message-passing in modular networks and the physics of magnetic spin-systems.

Message passing for integrating and assessing renewable generation in a redundant power grid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zdeborova, Lenka; Backhaus, Scott; Chertkov, Michael

2009-01-01

A simplified model of a redundant power grid is used to study integration of fluctuating renewable generation. The grid consists of large number of generator and consumer nodes. The net power consumption is determined by the difference between the gross consumption and the level of renewable generation. The gross consumption is drawn from a narrow distribution representing the predictability of aggregated loads, and we consider two different distributions representing wind and solar resources. Each generator is connected to D consumers, and redundancy is built in by connecting R {le} D of these consumers to other generators. The lines are switchablemore » so that at any instance each consumer is connected to a single generator. We explore the capacity of the renewable generation by determining the level of 'firm' generation capacity that can be displaced for different levels of redundancy R. We also develop message-passing control algorithm for finding switch sellings where no generator is overloaded.« less

Cellular automata with object-oriented features for parallel molecular network modeling.

PubMed

Zhu, Hao; Wu, Yinghui; Huang, Sui; Sun, Yan; Dhar, Pawan

2005-06-01

Cellular automata are an important modeling paradigm for studying the dynamics of large, parallel systems composed of multiple, interacting components. However, to model biological systems, cellular automata need to be extended beyond the large-scale parallelism and intensive communication in order to capture two fundamental properties characteristic of complex biological systems: hierarchy and heterogeneity. This paper proposes extensions to a cellular automata language, Cellang, to meet this purpose. The extended language, with object-oriented features, can be used to describe the structure and activity of parallel molecular networks within cells. Capabilities of this new programming language include object structure to define molecular programs within a cell, floating-point data type and mathematical functions to perform quantitative computation, message passing capability to describe molecular interactions, as well as new operators, statements, and built-in functions. We discuss relevant programming issues of these features, including the object-oriented description of molecular interactions with molecule encapsulation, message passing, and the description of heterogeneity and anisotropy at the cell and molecule levels. By enabling the integration of modeling at the molecular level with system behavior at cell, tissue, organ, or even organism levels, the program will help improve our understanding of how complex and dynamic biological activities are generated and controlled by parallel functioning of molecular networks. Index Terms-Cellular automata, modeling, molecular network, object-oriented.

Messaging to Increase Public Support for Naloxone Distribution Policies in the United States: Results from a Randomized Survey Experiment.

PubMed

Bachhuber, Marcus A; McGinty, Emma E; Kennedy-Hendricks, Alene; Niederdeppe, Jeff; Barry, Colleen L

2015-01-01

Barriers to public support for naloxone distribution include lack of knowledge, concerns about potential unintended consequences, and lack of sympathy for people at risk of overdose. A randomized survey experiment was conducted with a nationally-representative web-based survey research panel (GfK KnowledgePanel). Participants were randomly assigned to read different messages alone or in combination: 1) factual information about naloxone; 2) pre-emptive refutation of potential concerns about naloxone distribution; and 3) a sympathetic narrative about a mother whose daughter died of an opioid overdose. Participants were then asked if they support or oppose policies related to naloxone distribution. For each policy item, logistic regression models were used to test the effect of each message exposure compared with the no-exposure control group. The final sample consisted of 1,598 participants (completion rate: 72.6%). Factual information and the sympathetic narrative alone each led to higher support for training first responders to use naloxone, providing naloxone to friends and family members of people using opioids, and passing laws to protect people who administer naloxone. Participants receiving the combination of the sympathetic narrative and factual information, compared to factual information alone, were more likely to support all policies: providing naloxone to friends and family members (OR: 2.0 [95% CI: 1.4 to 2.9]), training first responders to use naloxone (OR: 2.0 [95% CI: 1.2 to 3.4]), passing laws to protect people if they administer naloxone (OR: 1.5 [95% CI: 1.04 to 2.2]), and passing laws to protect people if they call for medical help for an overdose (OR: 1.7 [95% CI: 1.2 to 2.5]). All messages increased public support, but combining factual information and the sympathetic narrative was most effective. Public support for naloxone distribution can be improved through education and sympathetic portrayals of the population who stands to benefit from these policies.

PRAIS: Distributed, real-time knowledge-based systems made easy

NASA Technical Reports Server (NTRS)

Goldstein, David G.

1990-01-01

This paper discusses an architecture for real-time, distributed (parallel) knowledge-based systems called the Parallel Real-time Artificial Intelligence System (PRAIS). PRAIS strives for transparently parallelizing production (rule-based) systems, even when under real-time constraints. PRAIS accomplishes these goals by incorporating a dynamic task scheduler, operating system extensions for fact handling, and message-passing among multiple copies of CLIPS executing on a virtual blackboard. This distributed knowledge-based system tool uses the portability of CLIPS and common message-passing protocols to operate over a heterogeneous network of processors.

Gene-network inference by message passing

NASA Astrophysics Data System (ADS)

Braunstein, A.; Pagnani, A.; Weigt, M.; Zecchina, R.

2008-01-01

The inference of gene-regulatory processes from gene-expression data belongs to the major challenges of computational systems biology. Here we address the problem from a statistical-physics perspective and develop a message-passing algorithm which is able to infer sparse, directed and combinatorial regulatory mechanisms. Using the replica technique, the algorithmic performance can be characterized analytically for artificially generated data. The algorithm is applied to genome-wide expression data of baker's yeast under various environmental conditions. We find clear cases of combinatorial control, and enrichment in common functional annotations of regulated genes and their regulators.

Optimal mapping of neural-network learning on message-passing multicomputers

NASA Technical Reports Server (NTRS)

Chu, Lon-Chan; Wah, Benjamin W.

1992-01-01

A minimization of learning-algorithm completion time is sought in the present optimal-mapping study of the learning process in multilayer feed-forward artificial neural networks (ANNs) for message-passing multicomputers. A novel approximation algorithm for mappings of this kind is derived from observations of the dominance of a parallel ANN algorithm over its communication time. Attention is given to both static and dynamic mapping schemes for systems with static and dynamic background workloads, as well as to experimental results obtained for simulated mappings on multicomputers with dynamic background workloads.

Trace-Driven Debugging of Message Passing Programs

NASA Technical Reports Server (NTRS)

Frumkin, Michael; Hood, Robert; Lopez, Louis; Bailey, David (Technical Monitor)

1998-01-01

In this paper we report on features added to a parallel debugger to simplify the debugging of parallel message passing programs. These features include replay, setting consistent breakpoints based on interprocess event causality, a parallel undo operation, and communication supervision. These features all use trace information collected during the execution of the program being debugged. We used a number of different instrumentation techniques to collect traces. We also implemented trace displays using two different trace visualization systems. The implementation was tested on an SGI Power Challenge cluster and a network of SGI workstations.

Multiple node remote messaging

DOEpatents

Blumrich, Matthias A.; Chen, Dong; Gara, Alan G.; Giampapa, Mark E.; Heidelberger, Philip; Ohmacht, Martin; Salapura, Valentina; Steinmacher-Burow, Burkhard; Vranas, Pavlos

2010-08-31

A method for passing remote messages in a parallel computer system formed as a network of interconnected compute nodes includes that a first compute node (A) sends a single remote message to a remote second compute node (B) in order to control the remote second compute node (B) to send at least one remote message. The method includes various steps including controlling a DMA engine at first compute node (A) to prepare the single remote message to include a first message descriptor and at least one remote message descriptor for controlling the remote second compute node (B) to send at least one remote message, including putting the first message descriptor into an injection FIFO at the first compute node (A) and sending the single remote message and the at least one remote message descriptor to the second compute node (B).

Time-Dependent Simulations of Incompressible Flow in a Turbopump Using Overset Grid Approach

NASA Technical Reports Server (NTRS)

Kiris, Cetin; Kwak, Dochan

2001-01-01

This viewgraph presentation provides information on mathematical modelling of the SSME (space shuttle main engine). The unsteady SSME-rig1 start-up procedure from the pump at rest has been initiated by using 34.3 million grid points. The computational model for the SSME-rig1 has been completed. Moving boundary capability is obtained by using DCF module in OVERFLOW-D. MPI (Message Passing Interface)/OpenMP hybrid parallel code has been benchmarked.

Three-pass protocol scheme for bitmap image security by using vernam cipher algorithm

NASA Astrophysics Data System (ADS)

Rachmawati, D.; Budiman, M. A.; Aulya, L.

2018-02-01

Confidentiality, integrity, and efficiency are the crucial aspects of data security. Among the other digital data, image data is too prone to abuse of operation like duplication, modification, etc. There are some data security techniques, one of them is cryptography. The security of Vernam Cipher cryptography algorithm is very dependent on the key exchange process. If the key is leaked, security of this algorithm will collapse. Therefore, a method that minimizes key leakage during the exchange of messages is required. The method which is used, is known as Three-Pass Protocol. This protocol enables message delivery process without the key exchange. Therefore, the sending messages process can reach the receiver safely without fear of key leakage. The system is built by using Java programming language. The materials which are used for system testing are image in size 200×200 pixel, 300×300 pixel, 500×500 pixel, 800×800 pixel and 1000×1000 pixel. The result of experiments showed that Vernam Cipher algorithm in Three-Pass Protocol scheme could restore the original image.

Ordering Traces Logically to Identify Lateness in Message Passing Programs

DOE PAGES

Isaacs, Katherine E.; Gamblin, Todd; Bhatele, Abhinav; ...

2015-03-30

Event traces are valuable for understanding the behavior of parallel programs. However, automatically analyzing a large parallel trace is difficult, especially without a specific objective. We aid this endeavor by extracting a trace's logical structure, an ordering of trace events derived from happened-before relationships, while taking into account developer intent. Using this structure, we can calculate an operation's delay relative to its peers on other processes. The logical structure also serves as a platform for comparing and clustering processes as well as highlighting communication patterns in a trace visualization. We present an algorithm for determining this idealized logical structure frommore » traces of message passing programs, and we develop metrics to quantify delays and differences among processes. We implement our techniques in Ravel, a parallel trace visualization tool that displays both logical and physical timelines. Rather than showing the duration of each operation, we display where delays begin and end, and how they propagate. As a result, we apply our approach to the traces of several message passing applications, demonstrating the accuracy of our extracted structure and its utility in analyzing these codes.« less

Dust Dynamics in Protoplanetary Disks: Parallel Computing with PVM

NASA Astrophysics Data System (ADS)

de La Fuente Marcos, Carlos; Barge, Pierre; de La Fuente Marcos, Raúl

2002-03-01

We describe a parallel version of our high-order-accuracy particle-mesh code for the simulation of collisionless protoplanetary disks. We use this code to carry out a massively parallel, two-dimensional, time-dependent, numerical simulation, which includes dust particles, to study the potential role of large-scale, gaseous vortices in protoplanetary disks. This noncollisional problem is easy to parallelize on message-passing multicomputer architectures. We performed the simulations on a cache-coherent nonuniform memory access Origin 2000 machine, using both the parallel virtual machine (PVM) and message-passing interface (MPI) message-passing libraries. Our performance analysis suggests that, for our problem, PVM is about 25% faster than MPI. Using PVM and MPI made it possible to reduce CPU time and increase code performance. This allows for simulations with a large number of particles (N ~ 105-106) in reasonable CPU times. The performances of our implementation of the pa! rallel code on an Origin 2000 supercomputer are presented and discussed. They exhibit very good speedup behavior and low load unbalancing. Our results confirm that giant gaseous vortices can play a dominant role in giant planet formation.

TravelAid : in-vehicle signing and variable speed limit evaluation

DOT National Transportation Integrated Search

2001-12-01

This report discusses the effectiveness of using variable message signs (VMSs) and in-vehicle traffic advisory systems (IVUs) on a mountainous pass (Snoqualmie Pass on Interstate 90 in Washington State) for changing driver behavior. As part of this p...

Clandestine Message Passing in Virtual Environments

DTIC Science & Technology

2008-09-01

accessed April 4, 2008). Weir, Laila. “Boring Game? Outsorce It.” (August 24, 2004). http://www.wired.com/ entertainment / music /news/2004/08/ 64638...Multiplayer Online MOVES - Modeling Virtual Environments and Simulation MTV – Music Television NPS - Naval Postgraduate School PAN – Personal Area...Network PSP - PlayStation Portable RPG – Role-playing Game SL - Second Life SVN - Subversion VE – Virtual Environments vMTV – Virtual Music

Statistical Inference in Graphical Models

DTIC Science & Technology

2008-06-17

fuse probability theory and graph theory in such a way as to permit efficient rep- resentation and computation with probability distributions. They...message passing. 59 viii 1. INTRODUCTION In approaching real-world problems, we often need to deal with uncertainty. Probability and statis- tics provide a...dynamic programming methods. However, for many sensors of interest, the signal-to-noise ratio does not allow such a treatment. Another source of

NAS Parallel Benchmark. Results 11-96: Performance Comparison of HPF and MPI Based NAS Parallel Benchmarks. 1.0

NASA Technical Reports Server (NTRS)

Saini, Subash; Bailey, David; Chancellor, Marisa K. (Technical Monitor)

1997-01-01

High Performance Fortran (HPF), the high-level language for parallel Fortran programming, is based on Fortran 90. HALF was defined by an informal standards committee known as the High Performance Fortran Forum (HPFF) in 1993, and modeled on TMC's CM Fortran language. Several HPF features have since been incorporated into the draft ANSI/ISO Fortran 95, the next formal revision of the Fortran standard. HPF allows users to write a single parallel program that can execute on a serial machine, a shared-memory parallel machine, or a distributed-memory parallel machine. HPF eliminates the complex, error-prone task of explicitly specifying how, where, and when to pass messages between processors on distributed-memory machines, or when to synchronize processors on shared-memory machines. HPF is designed in a way that allows the programmer to code an application at a high level, and then selectively optimize portions of the code by dropping into message-passing or calling tuned library routines as 'extrinsics'. Compilers supporting High Performance Fortran features first appeared in late 1994 and early 1995 from Applied Parallel Research (APR) Digital Equipment Corporation, and The Portland Group (PGI). IBM introduced an HPF compiler for the IBM RS/6000 SP/2 in April of 1996. Over the past two years, these implementations have shown steady improvement in terms of both features and performance. The performance of various hardware/ programming model (HPF and MPI (message passing interface)) combinations will be compared, based on latest NAS (NASA Advanced Supercomputing) Parallel Benchmark (NPB) results, thus providing a cross-machine and cross-model comparison. Specifically, HPF based NPB results will be compared with MPI based NPB results to provide perspective on performance currently obtainable using HPF versus MPI or versus hand-tuned implementations such as those supplied by the hardware vendors. In addition we would also present NPB (Version 1.0) performance results for the following systems: DEC Alpha Server 8400 5/440, Fujitsu VPP Series (VX, VPP300, and VPP700), HP/Convex Exemplar SPP2000, IBM RS/6000 SP P2SC node (120 MHz) NEC SX-4/32, SGI/CRAY T3E, SGI Origin2000.

Implementing TCP/IP and a socket interface as a server in a message-passing operating system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hipp, E.; Wiltzius, D.

1990-03-01

The UNICOS 4.3BSD network code and socket transport interface are the basis of an explicit network server for NLTSS, a message passing operating system on the Cray YMP. A BSD socket user library provides access to the network server using an RPC mechanism. The advantages of this server methodology are its modularity and extensibility to migrate to future protocol suites (e.g. OSI) and transport interfaces. In addition, the network server is implemented in an explicit multi-tasking environment to take advantage of the Cray YMP multi-processor platform. 19 refs., 5 figs.

A real-time MPEG software decoder using a portable message-passing library

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kwong, Man Kam; Tang, P.T. Peter; Lin, Biquan

1995-12-31

We present a real-time MPEG software decoder that uses message-passing libraries such as MPL, p4 and MPI. The parallel MPEG decoder currently runs on the IBM SP system but can be easil ported to other parallel machines. This paper discusses our parallel MPEG decoding algorithm as well as the parallel programming environment under which it uses. Several technical issues are discussed, including balancing of decoding speed, memory limitation, 1/0 capacities, and optimization of MPEG decoding components. This project shows that a real-time portable software MPEG decoder is feasible in a general-purpose parallel machine.

Complexity of parallel implementation of domain decomposition techniques for elliptic partial differential equations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gropp, W.D.; Keyes, D.E.

1988-03-01

The authors discuss the parallel implementation of preconditioned conjugate gradient (PCG)-based domain decomposition techniques for self-adjoint elliptic partial differential equations in two dimensions on several architectures. The complexity of these methods is described on a variety of message-passing parallel computers as a function of the size of the problem, number of processors and relative communication speeds of the processors. They show that communication startups are very important, and that even the small amount of global communication in these methods can significantly reduce the performance of many message-passing architectures.

n-body simulations using message passing parallel computers.

NASA Astrophysics Data System (ADS)

Grama, A. Y.; Kumar, V.; Sameh, A.

The authors present new parallel formulations of the Barnes-Hut method for n-body simulations on message passing computers. These parallel formulations partition the domain efficiently incurring minimal communication overhead. This is in contrast to existing schemes that are based on sorting a large number of keys or on the use of global data structures. The new formulations are augmented by alternate communication strategies which serve to minimize communication overhead. The impact of these communication strategies is experimentally studied. The authors report on experimental results obtained from an astrophysical simulation on an nCUBE2 parallel computer.

Cooperative Data Sharing: Simple Support for Clusters of SMP Nodes

NASA Technical Reports Server (NTRS)

DiNucci, David C.; Balley, David H. (Technical Monitor)

1997-01-01

Libraries like PVM and MPI send typed messages to allow for heterogeneous cluster computing. Lower-level libraries, such as GAM, provide more efficient access to communication by removing the need to copy messages between the interface and user space in some cases. still lower-level interfaces, such as UNET, get right down to the hardware level to provide maximum performance. However, these are all still interfaces for passing messages from one process to another, and have limited utility in a shared-memory environment, due primarily to the fact that message passing is just another term for copying. This drawback is made more pertinent by today's hybrid architectures (e.g. clusters of SMPs), where it is difficult to know beforehand whether two communicating processes will share memory. As a result, even portable language tools (like HPF compilers) must either map all interprocess communication, into message passing with the accompanying performance degradation in shared memory environments, or they must check each communication at run-time and implement the shared-memory case separately for efficiency. Cooperative Data Sharing (CDS) is a single user-level API which abstracts all communication between processes into the sharing and access coordination of memory regions, in a model which might be described as "distributed shared messages" or "large-grain distributed shared memory". As a result, the user programs to a simple latency-tolerant abstract communication specification which can be mapped efficiently to either a shared-memory or message-passing based run-time system, depending upon the available architecture. Unlike some distributed shared memory interfaces, the user still has complete control over the assignment of data to processors, the forwarding of data to its next likely destination, and the queuing of data until it is needed, so even the relatively high latency present in clusters can be accomodated. CDS does not require special use of an MMU, which can add overhead to some DSM systems, and does not require an SPMD programming model. unlike some message-passing interfaces, CDS allows the user to implement efficient demand-driven applications where processes must "fight" over data, and does not perform copying if processes share memory and do not attempt concurrent writes. CDS also supports heterogeneous computing, dynamic process creation, handlers, and a very simple thread-arbitration mechanism. Additional support for array subsections is currently being considered. The CDS1 API, which forms the kernel of CDS, is built primarily upon only 2 communication primitives, one process initiation primitive, and some data translation (and marshalling) routines, memory allocation routines, and priority control routines. The entire current collection of 28 routines provides enough functionality to implement most (or all) of MPI 1 and 2, which has a much larger interface consisting of hundreds of routines. still, the API is small enough to consider integrating into standard os interfaces for handling inter-process communication in a network-independent way. This approach would also help to solve many of the problems plaguing other higher-level standards such as MPI and PVM which must, in some cases, "play OS" to adequately address progress and process control issues. The CDS2 API, a higher level of interface roughly equivalent in functionality to MPI and to be built entirely upon CDS1, is still being designed. It is intended to add support for the equivalent of communicators, reduction and other collective operations, process topologies, additional support for process creation, and some automatic memory management. CDS2 will not exactly match MPI, because the copy-free semantics of communication from CDS1 will be supported. CDS2 application programs will be free to carefully also use CDS1. CDS1 has been implemented on networks of workstations running unmodified Unix-based operating systems, using UDP/IP and vendor-supplied high- performance locks. Although its inter-node performance is currently unimpressive due to rudimentary implementation technique, it even now outperforms highly-optimized MPI implementation on intra-node communication due to its support for non-copy communication. The similarity of the CDS1 architecture to that of other projects such as UNET and TRAP suggests that the inter-node performance can be increased significantly to surpass MPI or PVM, and it may be possible to migrate some of its functionality to communication controllers.

Parallelized direct execution simulation of message-passing parallel programs

NASA Technical Reports Server (NTRS)

Dickens, Phillip M.; Heidelberger, Philip; Nicol, David M.

1994-01-01

As massively parallel computers proliferate, there is growing interest in findings ways by which performance of massively parallel codes can be efficiently predicted. This problem arises in diverse contexts such as parallelizing computers, parallel performance monitoring, and parallel algorithm development. In this paper we describe one solution where one directly executes the application code, but uses a discrete-event simulator to model details of the presumed parallel machine such as operating system and communication network behavior. Because this approach is computationally expensive, we are interested in its own parallelization specifically the parallelization of the discrete-event simulator. We describe methods suitable for parallelized direct execution simulation of message-passing parallel programs, and report on the performance of such a system, Large Application Parallel Simulation Environment (LAPSE), we have built on the Intel Paragon. On all codes measured to date, LAPSE predicts performance well typically within 10 percent relative error. Depending on the nature of the application code, we have observed low slowdowns (relative to natively executing code) and high relative speedups using up to 64 processors.

Message Passing and Shared Address Space Parallelism on an SMP Cluster

NASA Technical Reports Server (NTRS)

Shan, Hongzhang; Singh, Jaswinder P.; Oliker, Leonid; Biswas, Rupak; Biegel, Bryan (Technical Monitor)

2002-01-01

Currently, message passing (MP) and shared address space (SAS) are the two leading parallel programming paradigms. MP has been standardized with MPI, and is the more common and mature approach; however, code development can be extremely difficult, especially for irregularly structured computations. SAS offers substantial ease of programming, but may suffer from performance limitations due to poor spatial locality and high protocol overhead. In this paper, we compare the performance of and the programming effort required for six applications under both programming models on a 32-processor PC-SMP cluster, a platform that is becoming increasingly attractive for high-end scientific computing. Our application suite consists of codes that typically do not exhibit scalable performance under shared-memory programming due to their high communication-to-computation ratios and/or complex communication patterns. Results indicate that SAS can achieve about half the parallel efficiency of MPI for most of our applications, while being competitive for the others. A hybrid MPI+SAS strategy shows only a small performance advantage over pure MPI in some cases. Finally, improved implementations of two MPI collective operations on PC-SMP clusters are presented.

Performance measurement and modeling of component applications in a high performance computing environment : a case study.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Armstrong, Robert C.; Ray, Jaideep; Malony, A.

2003-11-01

We present a case study of performance measurement and modeling of a CCA (Common Component Architecture) component-based application in a high performance computing environment. We explore issues peculiar to component-based HPC applications and propose a performance measurement infrastructure for HPC based loosely on recent work done for Grid environments. A prototypical implementation of the infrastructure is used to collect data for a three components in a scientific application and construct performance models for two of them. Both computational and message-passing performance are addressed.

[Old age in primary school readers: a journey through the end of the 19th century to the start of the 21st century in Argentina].

PubMed

Oddone, María Julieta

2013-04-01

This article presents the content (discourse) analysis of messages transmitted by primary school readers in the period between 1880 to 2012. This study allowed us to explore the image of old age and aging that society has and passes on to new generations as well as the role assigned to this generational group. The historical periods that provide the context for the data were defined according to the continuity of or the turning points in the social values transmitted in the reading materials. The role assigned to elderly people and the image of old age that the Argentine society passed on and continues to pass on to younger generations demonstrate that each period described has its own model of aging.

A Bayesian Model for Highly Accelerated Phase-Contrast MRI

PubMed Central

Rich, Adam; Potter, Lee C.; Jin, Ning; Ash, Joshua; Simonetti, Orlando P.; Ahmad, Rizwan

2015-01-01

Purpose Phase-contrast magnetic resonance imaging (PC-MRI) is a noninvasive tool to assess cardiovascular disease by quantifying blood flow; however, low data acquisition efficiency limits the spatial and temporal resolutions, real-time application, and extensions to 4D flow imaging in clinical settings. We propose a new data processing approach called Reconstructing Velocity Encoded MRI with Approximate message passing aLgorithms (ReVEAL) that accelerates the acquisition by exploiting data structure unique to PC-MRI. Theory and Methods ReVEAL models physical correlations across space, time, and velocity encodings. The proposed Bayesian approach exploits the relationships in both magnitude and phase among velocity encodings. A fast iterative recovery algorithm is introduced based on message passing. For validation, prospectively undersampled data are processed from a pulsatile flow phantom and five healthy volunteers. Results ReVEAL is in good agreement, quantified by peak velocity and stroke volume (SV), with reference data for acceleration rates R ≤ 10. For SV, Pearson r ≥ 0.996 for phantom imaging (n = 24) and r ≥ 0.956 for prospectively accelerated in vivo imaging (n = 10) for R ≤ 10. Conclusion ReVEAL enables accurate quantification of blood flow from highly undersampled data. The technique is extensible to 4D flow imaging, where higher acceleration may be possible due to additional redundancy. PMID:26444911

Relations Among Central Auditory Abilities, Socio-Economic Factors, Speech Delay, Phonic Abilities and Reading Achievement: A Longitudinal Study.

ERIC Educational Resources Information Center

Flowers, Arthur; Crandell, Edwin W.

Three auditory perceptual processes (resistance to distortion, selective listening in the form of auditory dedifferentiation, and binaural synthesis) were evaluated by five assessment techniques: (1) low pass filtered speech, (2) accelerated speech, (3) competing messages, (4) accelerated plus competing messages, and (5) binaural synthesis.…

ADHydro: A Parallel Implementation of a Large-scale High-Resolution Multi-Physics Distributed Water Resources Model Using the Charm++ Run Time System

NASA Astrophysics Data System (ADS)

Steinke, R. C.; Ogden, F. L.; Lai, W.; Moreno, H. A.; Pureza, L. G.

2014-12-01

Physics-based watershed models are useful tools for hydrologic studies, water resources management and economic analyses in the contexts of climate, land-use, and water-use changes. This poster presents a parallel implementation of a quasi 3-dimensional, physics-based, high-resolution, distributed water resources model suitable for simulating large watersheds in a massively parallel computing environment. Developing this model is one of the objectives of the NSF EPSCoR RII Track II CI-WATER project, which is joint between Wyoming and Utah EPSCoR jurisdictions. The model, which we call ADHydro, is aimed at simulating important processes in the Rocky Mountain west, including: rainfall and infiltration, snowfall and snowmelt in complex terrain, vegetation and evapotranspiration, soil heat flux and freezing, overland flow, channel flow, groundwater flow, water management and irrigation. Model forcing is provided by the Weather Research and Forecasting (WRF) model, and ADHydro is coupled with the NOAH-MP land-surface scheme for calculating fluxes between the land and atmosphere. The ADHydro implementation uses the Charm++ parallel run time system. Charm++ is based on location transparent message passing between migrateable C++ objects. Each object represents an entity in the model such as a mesh element. These objects can be migrated between processors or serialized to disk allowing the Charm++ system to automatically provide capabilities such as load balancing and checkpointing. Objects interact with each other by passing messages that the Charm++ system routes to the correct destination object regardless of its current location. This poster discusses the algorithms, communication patterns, and caching strategies used to implement ADHydro with Charm++. The ADHydro model code will be released to the hydrologic community in late 2014.

A Parallel Workload Model and its Implications for Processor Allocation

DTIC Science & Technology

1996-11-01

with SEV or AVG, both of which can tolerate c = 0.4 { 0.6 before their performance deteriorates signi cantly. On the other hand, Setia [10] has...Sanjeev. K Setia . The interaction between memory allocation and adaptive partitioning in message-passing multicomputers. In IPPS 󈨣 Workshop on Job...Scheduling Strategies for Parallel Processing, pages 89{99, 1995. [11] Sanjeev K. Setia and Satish K. Tripathi. An analysis of several processor

Asbestos: Securing Untrusted Software with Interposition

DTIC Science & Technology

2005-09-01

consistent intelligible interfaces to different types of resource. Message-based operating systems, such as Accent, Amoeba, Chorus, L4 , Spring...control on self-authenticating capabilities, precluding policies that restrict delegation. L4 uses a strict hierarchy of interpositions, useful for...the OS de- sign space amenable to secure application construction. Similar effects might be possible with message-passing microkernels , or unwieldy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Demeure, I.M.

The research presented here is concerned with representation techniques and tools to support the design, prototyping, simulation, and evaluation of message-based parallel, distributed computations. The author describes ParaDiGM-Parallel, Distributed computation Graph Model-a visual representation technique for parallel, message-based distributed computations. ParaDiGM provides several views of a computation depending on the aspect of concern. It is made of two complementary submodels, the DCPG-Distributed Computing Precedence Graph-model, and the PAM-Process Architecture Model-model. DCPGs are precedence graphs used to express the functionality of a computation in terms of tasks, message-passing, and data. PAM graphs are used to represent the partitioning of a computationmore » into schedulable units or processes, and the pattern of communication among those units. There is a natural mapping between the two models. He illustrates the utility of ParaDiGM as a representation technique by applying it to various computations (e.g., an adaptive global optimization algorithm, the client-server model). ParaDiGM representations are concise. They can be used in documenting the design and the implementation of parallel, distributed computations, in describing such computations to colleagues, and in comparing and contrasting various implementations of the same computation. He then describes VISA-VISual Assistant, a software tool to support the design, prototyping, and simulation of message-based parallel, distributed computations. VISA is based on the ParaDiGM model. In particular, it supports the editing of ParaDiGM graphs to describe the computations of interest, and the animation of these graphs to provide visual feedback during simulations. The graphs are supplemented with various attributes, simulation parameters, and interpretations which are procedures that can be executed by VISA.« less

Aspen: A microsimulation model of the economy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Basu, N.; Pryor, R.J.; Quint, T.

1996-10-01

This report presents, Aspen. Sandia National Laboratories is developing this new agent-based microeconomic simulation model of the U.S. economy. The model is notable because it allows a large number of individual economic agents to be modeled at a high level of detail and with a great degree of freedom. Some features of Aspen are (a) a sophisticated message-passing system that allows individual pairs of agents to communicate, (b) the use of genetic algorithms to simulate the learning of certain agents, and (c) a detailed financial sector that includes a banking system and a bond market. Results from runs of themore » model are also presented.« less

Comparing the OpenMP, MPI, and Hybrid Programming Paradigm on an SMP Cluster

NASA Technical Reports Server (NTRS)

Jost, Gabriele; Jin, Hao-Qiang; anMey, Dieter; Hatay, Ferhat F.

2003-01-01

Clusters of SMP (Symmetric Multi-Processors) nodes provide support for a wide range of parallel programming paradigms. The shared address space within each node is suitable for OpenMP parallelization. Message passing can be employed within and across the nodes of a cluster. Multiple levels of parallelism can be achieved by combining message passing and OpenMP parallelization. Which programming paradigm is the best will depend on the nature of the given problem, the hardware components of the cluster, the network, and the available software. In this study we compare the performance of different implementations of the same CFD benchmark application, using the same numerical algorithm but employing different programming paradigms.

ADAPTIVE TETRAHEDRAL GRID REFINEMENT AND COARSENING IN MESSAGE-PASSING ENVIRONMENTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hallberg, J.; Stagg, A.

2000-10-01

A grid refinement and coarsening scheme has been developed for tetrahedral and triangular grid-based calculations in message-passing environments. The element adaption scheme is based on an edge bisection of elements marked for refinement by an appropriate error indicator. Hash-table/linked-list data structures are used to store nodal and element formation. The grid along inter-processor boundaries is refined and coarsened consistently with the update of these data structures via MPI calls. The parallel adaption scheme has been applied to the solution of a transient, three-dimensional, nonlinear, groundwater flow problem. Timings indicate efficiency of the grid refinement process relative to the flow solvermore » calculations.« less

Learning classifier systems for single and multiple mobile robots in unstructured environments

NASA Astrophysics Data System (ADS)

Bay, John S.

1995-12-01

The learning classifier system (LCS) is a learning production system that generates behavioral rules via an underlying discovery mechanism. The LCS architecture operates similarly to a blackboard architecture; i.e., by posted-message communications. But in the LCS, the message board is wiped clean at every time interval, thereby requiring no persistent shared resource. In this paper, we adapt the LCS to the problem of mobile robot navigation in completely unstructured environments. We consider the model of the robot itself, including its sensor and actuator structures, to be part of this environment, in addition to the world-model that includes a goal and obstacles at unknown locations. This requires a robot to learn its own I/O characteristics in addition to solving its navigation problem, but results in a learning controller that is equally applicable, unaltered, in robots with a wide variety of kinematic structures and sensing capabilities. We show the effectiveness of this LCS-based controller through both simulation and experimental trials with a small robot. We then propose a new architecture, the Distributed Learning Classifier System (DLCS), which generalizes the message-passing behavior of the LCS from internal messages within a single agent to broadcast massages among multiple agents. This communications mode requires little bandwidth and is easily implemented with inexpensive, off-the-shelf hardware. The DLCS is shown to have potential application as a learning controller for multiple intelligent agents.

Discrete Event Simulation Modeling and Analysis of Key Leader Engagements

DTIC Science & Technology

2012-06-01

to offer. GreenPlayer agents require four parameters, pC, pKLK, pTK, and pRK , which give probabilities for being corrupt, having key leader...HandleMessageRequest component. The same parameter constraints apply to these four parameters. The parameter pRK is the same parameter from the CreatePlayers component...whether the local Green player has resource critical knowledge by using the parameter pRK . It schedules an EndResourceKnowledgeRequest event, passing

Weighted community detection and data clustering using message passing

NASA Astrophysics Data System (ADS)

Shi, Cheng; Liu, Yanchen; Zhang, Pan

2018-03-01

Grouping objects into clusters based on the similarities or weights between them is one of the most important problems in science and engineering. In this work, by extending message-passing algorithms and spectral algorithms proposed for an unweighted community detection problem, we develop a non-parametric method based on statistical physics, by mapping the problem to the Potts model at the critical temperature of spin-glass transition and applying belief propagation to solve the marginals corresponding to the Boltzmann distribution. Our algorithm is robust to over-fitting and gives a principled way to determine whether there are significant clusters in the data and how many clusters there are. We apply our method to different clustering tasks. In the community detection problem in weighted and directed networks, we show that our algorithm significantly outperforms existing algorithms. In the clustering problem, where the data were generated by mixture models in the sparse regime, we show that our method works all the way down to the theoretical limit of detectability and gives accuracy very close to that of the optimal Bayesian inference. In the semi-supervised clustering problem, our method only needs several labels to work perfectly in classic datasets. Finally, we further develop Thouless-Anderson-Palmer equations which heavily reduce the computation complexity in dense networks but give almost the same performance as belief propagation.

A Bayesian model for highly accelerated phase-contrast MRI.

PubMed

Rich, Adam; Potter, Lee C; Jin, Ning; Ash, Joshua; Simonetti, Orlando P; Ahmad, Rizwan

2016-08-01

Phase-contrast magnetic resonance imaging is a noninvasive tool to assess cardiovascular disease by quantifying blood flow; however, low data acquisition efficiency limits the spatial and temporal resolutions, real-time application, and extensions to four-dimensional flow imaging in clinical settings. We propose a new data processing approach called Reconstructing Velocity Encoded MRI with Approximate message passing aLgorithms (ReVEAL) that accelerates the acquisition by exploiting data structure unique to phase-contrast magnetic resonance imaging. The proposed approach models physical correlations across space, time, and velocity encodings. The proposed Bayesian approach exploits the relationships in both magnitude and phase among velocity encodings. A fast iterative recovery algorithm is introduced based on message passing. For validation, prospectively undersampled data are processed from a pulsatile flow phantom and five healthy volunteers. The proposed approach is in good agreement, quantified by peak velocity and stroke volume (SV), with reference data for acceleration rates R≤10. For SV, Pearson r≥0.99 for phantom imaging (n = 24) and r≥0.96 for prospectively accelerated in vivo imaging (n = 10) for R≤10. The proposed approach enables accurate quantification of blood flow from highly undersampled data. The technique is extensible to four-dimensional flow imaging, where higher acceleration may be possible due to additional redundancy. Magn Reson Med 76:689-701, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Performance analysis of distributed applications using automatic classification of communication inefficiencies

DOEpatents

Vetter, Jeffrey S.

2005-02-01

The method and system described herein presents a technique for performance analysis that helps users understand the communication behavior of their message passing applications. The method and system described herein may automatically classifies individual communication operations and reveal the cause of communication inefficiencies in the application. This classification allows the developer to quickly focus on the culprits of truly inefficient behavior, rather than manually foraging through massive amounts of performance data. Specifically, the method and system described herein trace the message operations of Message Passing Interface (MPI) applications and then classify each individual communication event using a supervised learning technique: decision tree classification. The decision tree may be trained using microbenchmarks that demonstrate both efficient and inefficient communication. Since the method and system described herein adapt to the target system's configuration through these microbenchmarks, they simultaneously automate the performance analysis process and improve classification accuracy. The method and system described herein may improve the accuracy of performance analysis and dramatically reduce the amount of data that users must encounter.

Impact of the infectious period on epidemics

NASA Astrophysics Data System (ADS)

Wilkinson, Robert R.; Sharkey, Kieran J.

2018-05-01

The duration of the infectious period is a crucial determinant of the ability of an infectious disease to spread. We consider an epidemic model that is network based and non-Markovian, containing classic Kermack-McKendrick, pairwise, message passing, and spatial models as special cases. For this model, we prove a monotonic relationship between the variability of the infectious period (with fixed mean) and the probability that the infection will reach any given subset of the population by any given time. For certain families of distributions, this result implies that epidemic severity is decreasing with respect to the variance of the infectious period. The striking importance of this relationship is demonstrated numerically. We then prove, with a fixed basic reproductive ratio (R0), a monotonic relationship between the variability of the posterior transmission probability (which is a function of the infectious period) and the probability that the infection will reach any given subset of the population by any given time. Thus again, even when R0 is fixed, variability of the infectious period tends to dampen the epidemic. Numerical results illustrate this but indicate the relationship is weaker. We then show how our results apply to message passing, pairwise, and Kermack-McKendrick epidemic models, even when they are not exactly consistent with the stochastic dynamics. For Poissonian contact processes, and arbitrarily distributed infectious periods, we demonstrate how systems of delay differential equations and ordinary differential equations can provide upper and lower bounds, respectively, for the probability that any given individual has been infected by any given time.

Implementation of a Message Passing Interface into a Cloud-Resolving Model for Massively Parallel Computing

NASA Technical Reports Server (NTRS)

Juang, Hann-Ming Henry; Tao, Wei-Kuo; Zeng, Xi-Ping; Shie, Chung-Lin; Simpson, Joanne; Lang, Steve

2004-01-01

The capability for massively parallel programming (MPP) using a message passing interface (MPI) has been implemented into a three-dimensional version of the Goddard Cumulus Ensemble (GCE) model. The design for the MPP with MPI uses the concept of maintaining similar code structure between the whole domain as well as the portions after decomposition. Hence the model follows the same integration for single and multiple tasks (CPUs). Also, it provides for minimal changes to the original code, so it is easily modified and/or managed by the model developers and users who have little knowledge of MPP. The entire model domain could be sliced into one- or two-dimensional decomposition with a halo regime, which is overlaid on partial domains. The halo regime requires that no data be fetched across tasks during the computational stage, but it must be updated before the next computational stage through data exchange via MPI. For reproducible purposes, transposing data among tasks is required for spectral transform (Fast Fourier Transform, FFT), which is used in the anelastic version of the model for solving the pressure equation. The performance of the MPI-implemented codes (i.e., the compressible and anelastic versions) was tested on three different computing platforms. The major results are: 1) both versions have speedups of about 99% up to 256 tasks but not for 512 tasks; 2) the anelastic version has better speedup and efficiency because it requires more computations than that of the compressible version; 3) equal or approximately-equal numbers of slices between the x- and y- directions provide the fastest integration due to fewer data exchanges; and 4) one-dimensional slices in the x-direction result in the slowest integration due to the need for more memory relocation for computation.

Earth Observation

NASA Image and Video Library

2013-08-20

Earth observation taken during day pass by an Expedition 36 crew member on board the International Space Station (ISS). Per Twitter message: Looking southwest over northern Africa. Libya, Algeria, Niger.

Application of a distributed network in computational fluid dynamic simulations

NASA Technical Reports Server (NTRS)

Deshpande, Manish; Feng, Jinzhang; Merkle, Charles L.; Deshpande, Ashish

1994-01-01

A general-purpose 3-D, incompressible Navier-Stokes algorithm is implemented on a network of concurrently operating workstations using parallel virtual machine (PVM) and compared with its performance on a CRAY Y-MP and on an Intel iPSC/860. The problem is relatively computationally intensive, and has a communication structure based primarily on nearest-neighbor communication, making it ideally suited to message passing. Such problems are frequently encountered in computational fluid dynamics (CDF), and their solution is increasingly in demand. The communication structure is explicitly coded in the implementation to fully exploit the regularity in message passing in order to produce a near-optimal solution. Results are presented for various grid sizes using up to eight processors.

Approximate message passing with restricted Boltzmann machine priors

NASA Astrophysics Data System (ADS)

Tramel, Eric W.; Drémeau, Angélique; Krzakala, Florent

2016-07-01

Approximate message passing (AMP) has been shown to be an excellent statistical approach to signal inference and compressed sensing problems. The AMP framework provides modularity in the choice of signal prior; here we propose a hierarchical form of the Gauss-Bernoulli prior which utilizes a restricted Boltzmann machine (RBM) trained on the signal support to push reconstruction performance beyond that of simple i.i.d. priors for signals whose support can be well represented by a trained binary RBM. We present and analyze two methods of RBM factorization and demonstrate how these affect signal reconstruction performance within our proposed algorithm. Finally, using the MNIST handwritten digit dataset, we show experimentally that using an RBM allows AMP to approach oracle-support performance.

New NAS Parallel Benchmarks Results

NASA Technical Reports Server (NTRS)

Yarrow, Maurice; Saphir, William; VanderWijngaart, Rob; Woo, Alex; Kutler, Paul (Technical Monitor)

1997-01-01

NPB2 (NAS (NASA Advanced Supercomputing) Parallel Benchmarks 2) is an implementation, based on Fortran and the MPI (message passing interface) message passing standard, of the original NAS Parallel Benchmark specifications. NPB2 programs are run with little or no tuning, in contrast to NPB vendor implementations, which are highly optimized for specific architectures. NPB2 results complement, rather than replace, NPB results. Because they have not been optimized by vendors, NPB2 implementations approximate the performance a typical user can expect for a portable parallel program on distributed memory parallel computers. Together these results provide an insightful comparison of the real-world performance of high-performance computers. New NPB2 features: New implementation (CG), new workstation class problem sizes, new serial sample versions, more performance statistics.

Analysis of multigrid methods on massively parallel computers: Architectural implications

NASA Technical Reports Server (NTRS)

Matheson, Lesley R.; Tarjan, Robert E.

1993-01-01

We study the potential performance of multigrid algorithms running on massively parallel computers with the intent of discovering whether presently envisioned machines will provide an efficient platform for such algorithms. We consider the domain parallel version of the standard V cycle algorithm on model problems, discretized using finite difference techniques in two and three dimensions on block structured grids of size 10(exp 6) and 10(exp 9), respectively. Our models of parallel computation were developed to reflect the computing characteristics of the current generation of massively parallel multicomputers. These models are based on an interconnection network of 256 to 16,384 message passing, 'workstation size' processors executing in an SPMD mode. The first model accomplishes interprocessor communications through a multistage permutation network. The communication cost is a logarithmic function which is similar to the costs in a variety of different topologies. The second model allows single stage communication costs only. Both models were designed with information provided by machine developers and utilize implementation derived parameters. With the medium grain parallelism of the current generation and the high fixed cost of an interprocessor communication, our analysis suggests an efficient implementation requires the machine to support the efficient transmission of long messages, (up to 1000 words) or the high initiation cost of a communication must be significantly reduced through an alternative optimization technique. Furthermore, with variable length message capability, our analysis suggests the low diameter multistage networks provide little or no advantage over a simple single stage communications network.

Development of mpi_EPIC model for global agroecosystem modeling

DOE PAGES

Kang, Shujiang; Wang, Dali; Jeff A. Nichols; ...

2014-12-31

Models that address policy-maker concerns about multi-scale effects of food and bioenergy production systems are computationally demanding. We integrated the message passing interface algorithm into the process-based EPIC model to accelerate computation of ecosystem effects. Simulation performance was further enhanced by applying the Vampir framework. When this enhanced mpi_EPIC model was tested, total execution time for a global 30-year simulation of a switchgrass cropping system was shortened to less than 0.5 hours on a supercomputer. The results illustrate that mpi_EPIC using parallel design can balance simulation workloads and facilitate large-scale, high-resolution analysis of agricultural production systems, management alternatives and environmentalmore » effects.« less

IMPETUS - Interactive MultiPhysics Environment for Unified Simulations.

PubMed

Ha, Vi Q; Lykotrafitis, George

2016-12-08

We introduce IMPETUS - Interactive MultiPhysics Environment for Unified Simulations, an object oriented, easy-to-use, high performance, C++ program for three-dimensional simulations of complex physical systems that can benefit a large variety of research areas, especially in cell mechanics. The program implements cross-communication between locally interacting particles and continuum models residing in the same physical space while a network facilitates long-range particle interactions. Message Passing Interface is used for inter-processor communication for all simulations. Copyright © 2016 Elsevier Ltd. All rights reserved.

Some Aspects of Parallel Implementation of the Finite Element Method on Message Passing Architectures

DTIC Science & Technology

1988-05-01

for Advanced Computer Studies and Department of Computer Science University of Maryland College Park, MD 20742 4, ABSTRACT We discuss some aspects of...Computer Studies and Technology & Dept. of Compute. Scienc II. CONTROLLING OFFICE NAME AND ADDRESS Viyriyf~ 12. REPORT DATE Department of the Navy uo...number)-1/ 2.) We study the performance of CG and PCG by examining its performance for u E (0,1), for solving the two model problems with an accuracy

Earth observation taken by the Expedition 46 crew

NASA Image and Video Library

2016-01-23

ISS046e021993 (01/23/2016) --- Earth observation of the coast of Oman taken during a night pass by the Expedition 46 crew aboard the International Space Station. NASA astronaut Tim Kopra tweeted this image out with this message: "Passing over the Gulf of #Oman at night -- city lights of #Muscat #Dubai #AbuDhabi and #Doha in the distance".

Optimisation of a parallel ocean general circulation model

NASA Astrophysics Data System (ADS)

Beare, M. I.; Stevens, D. P.

1997-10-01

This paper presents the development of a general-purpose parallel ocean circulation model, for use on a wide range of computer platforms, from traditional scalar machines to workstation clusters and massively parallel processors. Parallelism is provided, as a modular option, via high-level message-passing routines, thus hiding the technical intricacies from the user. An initial implementation highlights that the parallel efficiency of the model is adversely affected by a number of factors, for which optimisations are discussed and implemented. The resulting ocean code is portable and, in particular, allows science to be achieved on local workstations that could otherwise only be undertaken on state-of-the-art supercomputers.

Software architecture for time-constrained machine vision applications

NASA Astrophysics Data System (ADS)

Usamentiaga, Rubén; Molleda, Julio; García, Daniel F.; Bulnes, Francisco G.

2013-01-01

Real-time image and video processing applications require skilled architects, and recent trends in the hardware platform make the design and implementation of these applications increasingly complex. Many frameworks and libraries have been proposed or commercialized to simplify the design and tuning of real-time image processing applications. However, they tend to lack flexibility, because they are normally oriented toward particular types of applications, or they impose specific data processing models such as the pipeline. Other issues include large memory footprints, difficulty for reuse, and inefficient execution on multicore processors. We present a novel software architecture for time-constrained machine vision applications that addresses these issues. The architecture is divided into three layers. The platform abstraction layer provides a high-level application programming interface for the rest of the architecture. The messaging layer provides a message-passing interface based on a dynamic publish/subscribe pattern. A topic-based filtering in which messages are published to topics is used to route the messages from the publishers to the subscribers interested in a particular type of message. The application layer provides a repository for reusable application modules designed for machine vision applications. These modules, which include acquisition, visualization, communication, user interface, and data processing, take advantage of the power of well-known libraries such as OpenCV, Intel IPP, or CUDA. Finally, the proposed architecture is applied to a real machine vision application: a jam detector for steel pickling lines.

Role of Edges in Complex Network Epidemiology

NASA Astrophysics Data System (ADS)

Zhang, Hao; Jiang, Zhi-Hong; Wang, Hui; Xie, Fei; Chen, Chao

2012-09-01

In complex network epidemiology, diseases spread along contacting edges between individuals and different edges may play different roles in epidemic outbreaks. Quantifying the efficiency of edges is an important step towards arresting epidemics. In this paper, we study the efficiency of edges in general susceptible-infected-recovered models, and introduce the transmission capability to measure the efficiency of edges. Results show that deleting edges with the highest transmission capability will greatly decrease epidemics on scale-free networks. Basing on the message passing approach, we get exact mathematical solution on configuration model networks with edge deletion in the large size limit.

Teaching Controversial Topics to Skeptical High School Students

NASA Astrophysics Data System (ADS)

Ford, K. S.

2012-12-01

Tennessee passes the "Monkey Bill" (HB 0368, SB 0893), North Carolina's state government passes a law to criminalize reference in state documents to scientific models that predict sea level rise to reach at least one meter by the next century, and public concern still lags far behind the scientific community's concern on climate change. The American public and even science teachers across the country seem to have lost faith in the ability of the scientific community to unify a strong message about several important scientific lessons, including global warming in particular. This lack of a unified message has weakened the ability of science teachers to effectively teach the lesson of global warming. For science teachers in strongly conservative areas of the country, it is much easier to omit difficult topics and avoid angering parents and school board members. Teachers who do feel strongly about scientifically proven, yet publically controversial topics CAN teach these topics in conservative areas by confirming students' belief systems by being honest and open about motivations surrounding both sides of controversial topics, and by using vocabulary that avoids triggering negative perceptions about these controversial topics. For true learning and change of preconceived opinion to take place, it is important for students to come to the understanding in their own minds in an open and safe learning environment instead of having the message "preached" to them, which only serves to make them feel unintelligent and defensive if they disagree. This presentation will include lessons learned from a practicing science teacher who works in a community that overwhelmingly disputes the validity of human impacts on climate change.

Earth Observation

NASA Image and Video Library

2013-08-03

Earth observation taken during day pass by an Expedition 36 crew member on board the International Space Station (ISS). Per Twitter message: Perhaps a dandelion losing its seeds in the wind? Love clouds!

Paralysis

MedlinePlus

Paralysis is the loss of muscle function in part of your body. It happens when something goes ... way messages pass between your brain and muscles. Paralysis can be complete or partial. It can occur ...

Advanced Numerical Techniques of Performance Evaluation. Volume 2

DTIC Science & Technology

1990-06-01

multiprocessor environment. This factor is determined by the overhead of the primitives available in the system ( semaphore , monitor , or message... semaphore , monitor , or message passing primitives ) and U the programming ability of the user who implements the simulation. " t,: the sequential...Warp Operating System . i Pro" lftevcnth ACM Symposum on Operating Systems Princlplcs, pages 77 9:3, Auslin, TX, Nov wicr 1987. ACM. [121 D.R. Jefferson

Benchmarking hypercube hardware and software

NASA Technical Reports Server (NTRS)

Grunwald, Dirk C.; Reed, Daniel A.

1986-01-01

It was long a truism in computer systems design that balanced systems achieve the best performance. Message passing parallel processors are no different. To quantify the balance of a hypercube design, an experimental methodology was developed and the associated suite of benchmarks was applied to several existing hypercubes. The benchmark suite includes tests of both processor speed in the absence of internode communication and message transmission speed as a function of communication patterns.

Data transfer using complete bipartite graph

NASA Astrophysics Data System (ADS)

Chandrasekaran, V. M.; Praba, B.; Manimaran, A.; Kailash, G.

2017-11-01

Information exchange extent is an estimation of the amount of information sent between two focuses on a framework in a given time period. It is an extremely significant perception in present world. There are many ways of message passing in the present situations. Some of them are through encryption, decryption, by using complete bipartite graph. In this paper, we recommend a method for communication using messages through encryption of a complete bipartite graph.

Statistical mechanics of complex neural systems and high dimensional data

NASA Astrophysics Data System (ADS)

Advani, Madhu; Lahiri, Subhaneil; Ganguli, Surya

2013-03-01

Recent experimental advances in neuroscience have opened new vistas into the immense complexity of neuronal networks. This proliferation of data challenges us on two parallel fronts. First, how can we form adequate theoretical frameworks for understanding how dynamical network processes cooperate across widely disparate spatiotemporal scales to solve important computational problems? Second, how can we extract meaningful models of neuronal systems from high dimensional datasets? To aid in these challenges, we give a pedagogical review of a collection of ideas and theoretical methods arising at the intersection of statistical physics, computer science and neurobiology. We introduce the interrelated replica and cavity methods, which originated in statistical physics as powerful ways to quantitatively analyze large highly heterogeneous systems of many interacting degrees of freedom. We also introduce the closely related notion of message passing in graphical models, which originated in computer science as a distributed algorithm capable of solving large inference and optimization problems involving many coupled variables. We then show how both the statistical physics and computer science perspectives can be applied in a wide diversity of contexts to problems arising in theoretical neuroscience and data analysis. Along the way we discuss spin glasses, learning theory, illusions of structure in noise, random matrices, dimensionality reduction and compressed sensing, all within the unified formalism of the replica method. Moreover, we review recent conceptual connections between message passing in graphical models, and neural computation and learning. Overall, these ideas illustrate how statistical physics and computer science might provide a lens through which we can uncover emergent computational functions buried deep within the dynamical complexities of neuronal networks.

Trellis Tone Modulation Multiple-Access for Peer Discovery in D2D Networks

PubMed Central

Lim, Chiwoo; Kim, Sang-Hyo

2018-01-01

In this paper, a new non-orthogonal multiple-access scheme, trellis tone modulation multiple-access (TTMMA), is proposed for peer discovery of distributed device-to-device (D2D) communication. The range and capacity of discovery are important performance metrics in peer discovery. The proposed trellis tone modulation uses single-tone transmission and achieves a long discovery range due to its low Peak-to-Average Power Ratio (PAPR). The TTMMA also exploits non-orthogonal resource assignment to increase the discovery capacity. For the multi-user detection of superposed multiple-access signals, a message-passing algorithm with supplementary schemes are proposed. With TTMMA and its message-passing demodulation, approximately 1.5 times the number of devices are discovered compared to the conventional frequency division multiple-access (FDMA)-based discovery. PMID:29673167

Statistical physics of hard combinatorial optimization: Vertex cover problem

NASA Astrophysics Data System (ADS)

Zhao, Jin-Hua; Zhou, Hai-Jun

2014-07-01

Typical-case computation complexity is a research topic at the boundary of computer science, applied mathematics, and statistical physics. In the last twenty years, the replica-symmetry-breaking mean field theory of spin glasses and the associated message-passing algorithms have greatly deepened our understanding of typical-case computation complexity. In this paper, we use the vertex cover problem, a basic nondeterministic-polynomial (NP)-complete combinatorial optimization problem of wide application, as an example to introduce the statistical physical methods and algorithms. We do not go into the technical details but emphasize mainly the intuitive physical meanings of the message-passing equations. A nonfamiliar reader shall be able to understand to a large extent the physics behind the mean field approaches and to adjust the mean field methods in solving other optimization problems.

Trellis Tone Modulation Multiple-Access for Peer Discovery in D2D Networks.

PubMed

Lim, Chiwoo; Jang, Min; Kim, Sang-Hyo

2018-04-17

In this paper, a new non-orthogonal multiple-access scheme, trellis tone modulation multiple-access (TTMMA), is proposed for peer discovery of distributed device-to-device (D2D) communication. The range and capacity of discovery are important performance metrics in peer discovery. The proposed trellis tone modulation uses single-tone transmission and achieves a long discovery range due to its low Peak-to-Average Power Ratio (PAPR). The TTMMA also exploits non-orthogonal resource assignment to increase the discovery capacity. For the multi-user detection of superposed multiple-access signals, a message-passing algorithm with supplementary schemes are proposed. With TTMMA and its message-passing demodulation, approximately 1.5 times the number of devices are discovered compared to the conventional frequency division multiple-access (FDMA)-based discovery.

Multi-partitioning for ADI-schemes on message passing architectures

NASA Technical Reports Server (NTRS)

Vanderwijngaart, Rob F.

1994-01-01

A kind of discrete-operator splitting called Alternating Direction Implicit (ADI) has been found to be useful in simulating fluid flow problems. In particular, it is being used to study the effects of hot exhaust jets from high performance aircraft on landing surfaces. Decomposition techniques that minimize load imbalance and message-passing frequency are described. Three strategies that are investigated for implementing the NAS Scalar Penta-diagonal Parallel Benchmark (SP) are transposition, pipelined Gaussian elimination, and multipartitioning. The multipartitioning strategy, which was used on Ethernet, was found to be the most efficient, although it was considered only a moderate success because of Ethernet's limited communication properties. The efficiency derived largely from the coarse granularity of the strategy, which reduced latencies and allowed overlap of communication and computation.

Ultrascalable petaflop parallel supercomputer

DOEpatents

Blumrich, Matthias A [Ridgefield, CT; Chen, Dong [Croton On Hudson, NY; Chiu, George [Cross River, NY; Cipolla, Thomas M [Katonah, NY; Coteus, Paul W [Yorktown Heights, NY; Gara, Alan G [Mount Kisco, NY; Giampapa, Mark E [Irvington, NY; Hall, Shawn [Pleasantville, NY; Haring, Rudolf A [Cortlandt Manor, NY; Heidelberger, Philip [Cortlandt Manor, NY; Kopcsay, Gerard V [Yorktown Heights, NY; Ohmacht, Martin [Yorktown Heights, NY; Salapura, Valentina [Chappaqua, NY; Sugavanam, Krishnan [Mahopac, NY; Takken, Todd [Brewster, NY

2010-07-20

A massively parallel supercomputer of petaOPS-scale includes node architectures based upon System-On-a-Chip technology, where each processing node comprises a single Application Specific Integrated Circuit (ASIC) having up to four processing elements. The ASIC nodes are interconnected by multiple independent networks that optimally maximize the throughput of packet communications between nodes with minimal latency. The multiple networks may include three high-speed networks for parallel algorithm message passing including a Torus, collective network, and a Global Asynchronous network that provides global barrier and notification functions. These multiple independent networks may be collaboratively or independently utilized according to the needs or phases of an algorithm for optimizing algorithm processing performance. The use of a DMA engine is provided to facilitate message passing among the nodes without the expenditure of processing resources at the node.

Incremental Parallelization of Non-Data-Parallel Programs Using the Charon Message-Passing Library

NASA Technical Reports Server (NTRS)

VanderWijngaart, Rob F.

2000-01-01

Message passing is among the most popular techniques for parallelizing scientific programs on distributed-memory architectures. The reasons for its success are wide availability (MPI), efficiency, and full tuning control provided to the programmer. A major drawback, however, is that incremental parallelization, as offered by compiler directives, is not generally possible, because all data structures have to be changed throughout the program simultaneously. Charon remedies this situation through mappings between distributed and non-distributed data. It allows breaking up the parallelization into small steps, guaranteeing correctness at every stage. Several tools are available to help convert legacy codes into high-performance message-passing programs. They usually target data-parallel applications, whose loops carrying most of the work can be distributed among all processors without much dependency analysis. Others do a full dependency analysis and then convert the code virtually automatically. Even more toolkits are available that aid construction from scratch of message passing programs. None, however, allows piecemeal translation of codes with complex data dependencies (i.e. non-data-parallel programs) into message passing codes. The Charon library (available in both C and Fortran) provides incremental parallelization capabilities by linking legacy code arrays with distributed arrays. During the conversion process, non-distributed and distributed arrays exist side by side, and simple mapping functions allow the programmer to switch between the two in any location in the program. Charon also provides wrapper functions that leave the structure of the legacy code intact, but that allow execution on truly distributed data. Finally, the library provides a rich set of communication functions that support virtually all patterns of remote data demands in realistic structured grid scientific programs, including transposition, nearest-neighbor communication, pipelining, gather/scatter, and redistribution. At the end of the conversion process most intermediate Charon function calls will have been removed, the non-distributed arrays will have been deleted, and virtually the only remaining Charon functions calls are the high-level, highly optimized communications. Distribution of the data is under complete control of the programmer, although a wide range of useful distributions is easily available through predefined functions. A crucial aspect of the library is that it does not allocate space for distributed arrays, but accepts programmer-specified memory. This has two major consequences. First, codes parallelized using Charon do not suffer from encapsulation; user data is always directly accessible. This provides high efficiency, and also retains the possibility of using message passing directly for highly irregular communications. Second, non-distributed arrays can be interpreted as (trivial) distributions in the Charon sense, which allows them to be mapped to truly distributed arrays, and vice versa. This is the mechanism that enables incremental parallelization. In this paper we provide a brief introduction of the library and then focus on the actual steps in the parallelization process, using some representative examples from, among others, the NAS Parallel Benchmarks. We show how a complicated two-dimensional pipeline-the prototypical non-data-parallel algorithm- can be constructed with ease. To demonstrate the flexibility of the library, we give examples of the stepwise, efficient parallel implementation of nonlocal boundary conditions common in aircraft simulations, as well as the construction of the sequence of grids required for multigrid.

Message Passing on GPUs

NASA Astrophysics Data System (ADS)

Stuart, J. A.

2011-12-01

This paper explores the challenges in implementing a message passing interface usable on systems with data-parallel processors, and more specifically GPUs. As a case study, we design and implement the ``DCGN'' API on NVIDIA GPUs that is similar to MPI and allows full access to the underlying architecture. We introduce the notion of data-parallel thread-groups as a way to map resources to MPI ranks. We use a method that also allows the data-parallel processors to run autonomously from user-written CPU code. In order to facilitate communication, we use a sleep-based polling system to store and retrieve messages. Unlike previous systems, our method provides both performance and flexibility. By running a test suite of applications with different communication requirements, we find that a tolerable amount of overhead is incurred, somewhere between one and five percent depending on the application, and indicate the locations where this overhead accumulates. We conclude that with innovations in chipsets and drivers, this overhead will be mitigated and provide similar performance to typical CPU-based MPI implementations while providing fully-dynamic communication.

Constrained low-rank matrix estimation: phase transitions, approximate message passing and applications

NASA Astrophysics Data System (ADS)

Lesieur, Thibault; Krzakala, Florent; Zdeborová, Lenka

2017-07-01

This article is an extended version of previous work of Lesieur et al (2015 IEEE Int. Symp. on Information Theory Proc. pp 1635-9 and 2015 53rd Annual Allerton Conf. on Communication, Control and Computing (IEEE) pp 680-7) on low-rank matrix estimation in the presence of constraints on the factors into which the matrix is factorized. Low-rank matrix factorization is one of the basic methods used in data analysis for unsupervised learning of relevant features and other types of dimensionality reduction. We present a framework to study the constrained low-rank matrix estimation for a general prior on the factors, and a general output channel through which the matrix is observed. We draw a parallel with the study of vector-spin glass models—presenting a unifying way to study a number of problems considered previously in separate statistical physics works. We present a number of applications for the problem in data analysis. We derive in detail a general form of the low-rank approximate message passing (Low-RAMP) algorithm, that is known in statistical physics as the TAP equations. We thus unify the derivation of the TAP equations for models as different as the Sherrington-Kirkpatrick model, the restricted Boltzmann machine, the Hopfield model or vector (xy, Heisenberg and other) spin glasses. The state evolution of the Low-RAMP algorithm is also derived, and is equivalent to the replica symmetric solution for the large class of vector-spin glass models. In the section devoted to result we study in detail phase diagrams and phase transitions for the Bayes-optimal inference in low-rank matrix estimation. We present a typology of phase transitions and their relation to performance of algorithms such as the Low-RAMP or commonly used spectral methods.

A flexible software architecture for scalable real-time image and video processing applications

NASA Astrophysics Data System (ADS)

Usamentiaga, Rubén; Molleda, Julio; García, Daniel F.; Bulnes, Francisco G.

2012-06-01

Real-time image and video processing applications require skilled architects, and recent trends in the hardware platform make the design and implementation of these applications increasingly complex. Many frameworks and libraries have been proposed or commercialized to simplify the design and tuning of real-time image processing applications. However, they tend to lack flexibility because they are normally oriented towards particular types of applications, or they impose specific data processing models such as the pipeline. Other issues include large memory footprints, difficulty for reuse and inefficient execution on multicore processors. This paper presents a novel software architecture for real-time image and video processing applications which addresses these issues. The architecture is divided into three layers: the platform abstraction layer, the messaging layer, and the application layer. The platform abstraction layer provides a high level application programming interface for the rest of the architecture. The messaging layer provides a message passing interface based on a dynamic publish/subscribe pattern. A topic-based filtering in which messages are published to topics is used to route the messages from the publishers to the subscribers interested in a particular type of messages. The application layer provides a repository for reusable application modules designed for real-time image and video processing applications. These modules, which include acquisition, visualization, communication, user interface and data processing modules, take advantage of the power of other well-known libraries such as OpenCV, Intel IPP, or CUDA. Finally, we present different prototypes and applications to show the possibilities of the proposed architecture.

Sequentially Executed Model Evaluation Framework

DOE Office of Scientific and Technical Information (OSTI.GOV)

2015-10-20

Provides a message passing framework between generic input, model and output drivers, and specifies an API for developing such drivers. Also provides batch and real-time controllers which step the model and I/O through the time domain (or other discrete domain), and sample I/O drivers. This is a library framework, and does not, itself, solve any problems or execute any modeling. The SeMe framework aids in development of models which operate on sequential information, such as time-series, where evaluation is based on prior results combined with new data for this iteration. Has applications in quality monitoring, and was developed as partmore » of the CANARY-EDS software, where real-time water quality data is being analyzed for anomalies.« less

Applications of Probabilistic Combiners on Linear Feedback Shift Register Sequences

DTIC Science & Technology

2016-12-01

on the resulting output strings show a drastic increase in complexity, while simultaneously passing the stringent randomness tests required by the...a three-variable function. Our tests on the resulting output strings show a drastic increase in complex- ity, while simultaneously passing the...10001101 01000010 11101001 Decryption of a message that has been encrypted using bitwise XOR is quite simple. Since each bit is its own additive inverse

Earth Observation

NASA Image and Video Library

2013-07-26

Earth observation taken during day pass by an Expedition 36 crew member on board the International Space Station (ISS). Per Twitter message: Never tire of finding shapes in the clouds! These look very botanical to me. Simply perfect.

PREEMIE Reauthorization Act

THOMAS, 112th Congress

Sen. Alexander, Lamar [R-TN

2011-07-28

Senate - 12/19/2012 Message on House action received in Senate and at desk: House amendments to Senate bill. (All Actions) Tracker: This bill has the status Passed HouseHere are the steps for Status of Legislation:

Electronic Cigarettes on Twitter – Spreading the Appeal of Flavors

PubMed Central

Chu, Kar-Hai; Unger, Jennifer B.; Cruz, Tess Boley; Soto, Daniel W.

2016-01-01

Objectives Social media platforms are used by tobacco companies to promote products. This study examines message content on Twitter from e-cigarette brands and determines if messages about flavors are more likely than non-flavor messages to be passed along to other viewers. Methods We examined Twitter data from 2 e-cigarette brands and identified messages that contained terms related to e-cigarette flavors. Results Flavor-related posts were retweeted at a significantly higher rate by e-cigarette brands (p = .04) and other Twitter users (p < .01) than non-flavor posts. Conclusions E-cigarette brands and other Twitter users pay attention to flavor-related posts and retweet them often. These findings suggest flavors continue to be an attractive characteristic and their marketing should be monitored closely. PMID:27853734

Comparing the Performance of Two Dynamic Load Distribution Methods

NASA Technical Reports Server (NTRS)

Kale, L. V.

1987-01-01

Parallel processing of symbolic computations on a message-passing multi-processor presents one challenge: To effectively utilize the available processors, the load must be distributed uniformly to all the processors. However, the structure of these computations cannot be predicted in advance. go, static scheduling methods are not applicable. In this paper, we compare the performance of two dynamic, distributed load balancing methods with extensive simulation studies. The two schemes are: the Contracting Within a Neighborhood (CWN) scheme proposed by us, and the Gradient Model proposed by Lin and Keller. We conclude that although simpler, the CWN is significantly more effective at distributing the work than the Gradient model.

Heartbeat-based error diagnosis framework for distributed embedded systems

NASA Astrophysics Data System (ADS)

Mishra, Swagat; Khilar, Pabitra Mohan

2012-01-01

Distributed Embedded Systems have significant applications in automobile industry as steer-by-wire, fly-by-wire and brake-by-wire systems. In this paper, we provide a general framework for fault detection in a distributed embedded real time system. We use heartbeat monitoring, check pointing and model based redundancy to design a scalable framework that takes care of task scheduling, temperature control and diagnosis of faulty nodes in a distributed embedded system. This helps in diagnosis and shutting down of faulty actuators before the system becomes unsafe. The framework is designed and tested using a new simulation model consisting of virtual nodes working on a message passing system.

Heartbeat-based error diagnosis framework for distributed embedded systems

NASA Astrophysics Data System (ADS)

Mishra, Swagat; Khilar, Pabitra Mohan

2011-12-01

Distributed Embedded Systems have significant applications in automobile industry as steer-by-wire, fly-by-wire and brake-by-wire systems. In this paper, we provide a general framework for fault detection in a distributed embedded real time system. We use heartbeat monitoring, check pointing and model based redundancy to design a scalable framework that takes care of task scheduling, temperature control and diagnosis of faulty nodes in a distributed embedded system. This helps in diagnosis and shutting down of faulty actuators before the system becomes unsafe. The framework is designed and tested using a new simulation model consisting of virtual nodes working on a message passing system.

Identifying an influential spreader from a single seed in complex networks via a message-passing approach

NASA Astrophysics Data System (ADS)

Min, Byungjoon

2018-01-01

Identifying the most influential spreaders is one of outstanding problems in physics of complex systems. So far, many approaches have attempted to rank the influence of nodes but there is still the lack of accuracy to single out influential spreaders. Here, we directly tackle the problem of finding important spreaders by solving analytically the expected size of epidemic outbreaks when spreading originates from a single seed. We derive and validate a theory for calculating the size of epidemic outbreaks with a single seed using a message-passing approach. In addition, we find that the probability to occur epidemic outbreaks is highly dependent on the location of the seed but the size of epidemic outbreaks once it occurs is insensitive to the seed. We also show that our approach can be successfully adapted into weighted networks.

Generalized hypercube structures and hyperswitch communication network

NASA Technical Reports Server (NTRS)

Young, Steven D.

1992-01-01

This paper discusses an ongoing study that uses a recent development in communication control technology to implement hybrid hypercube structures. These architectures are similar to binary hypercubes, but they also provide added connectivity between the processors. This added connectivity increases communication reliability while decreasing the latency of interprocessor message passing. Because these factors directly determine the speed that can be obtained by multiprocessor systems, these architectures are attractive for applications such as remote exploration and experimentation, where high performance and ultrareliability are required. This paper describes and enumerates these architectures and discusses how they can be implemented with a modified version of the hyperswitch communication network (HCN). The HCN is analyzed because it has three attractive features that enable these architectures to be effective: speed, fault tolerance, and the ability to pass multiple messages simultaneously through the same hyperswitch controller.

Porting LAMMPS to GPUs.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, William Michael; Plimpton, Steven James; Wang, Peng

2010-03-01

LAMMPS is a classical molecular dynamics code, and an acronym for Large-scale Atomic/Molecular Massively Parallel Simulator. LAMMPS has potentials for soft materials (biomolecules, polymers) and solid-state materials (metals, semiconductors) and coarse-grained or mesoscopic systems. It can be used to model atoms or, more generically, as a parallel particle simulator at the atomic, meso, or continuum scale. LAMMPS runs on single processors or in parallel using message-passing techniques and a spatial-decomposition of the simulation domain. The code is designed to be easy to modify or extend with new functionality.

High-energy physics software parallelization using database techniques

NASA Astrophysics Data System (ADS)

Argante, E.; van der Stok, P. D. V.; Willers, I.

1997-02-01

A programming model for software parallelization, called CoCa, is introduced that copes with problems caused by typical features of high-energy physics software. By basing CoCa on the database transaction paradimg, the complexity induced by the parallelization is for a large part transparent to the programmer, resulting in a higher level of abstraction than the native message passing software. CoCa is implemented on a Meiko CS-2 and on a SUN SPARCcenter 2000 parallel computer. On the CS-2, the performance is comparable with the performance of native PVM and MPI.

Computer-aided programming for message-passing system; Problems and a solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, M.Y.; Gajski, D.D.

1989-12-01

As the number of processors and the complexity of problems to be solved increase, programming multiprocessing systems becomes more difficult and error-prone. Program development tools are necessary since programmers are not able to develop complex parallel programs efficiently. Parallel models of computation, parallelization problems, and tools for computer-aided programming (CAP) are discussed. As an example, a CAP tool that performs scheduling and inserts communication primitives automatically is described. It also generates the performance estimates and other program quality measures to help programmers in improving their algorithms and programs.

Flood predictions using the parallel version of distributed numerical physical rainfall-runoff model TOPKAPI

NASA Astrophysics Data System (ADS)

Boyko, Oleksiy; Zheleznyak, Mark

2015-04-01

The original numerical code TOPKAPI-IMMS of the distributed rainfall-runoff model TOPKAPI ( Todini et al, 1996-2014) is developed and implemented in Ukraine. The parallel version of the code has been developed recently to be used on multiprocessors systems - multicore/processors PC and clusters. Algorithm is based on binary-tree decomposition of the watershed for the balancing of the amount of computation for all processors/cores. Message passing interface (MPI) protocol is used as a parallel computing framework. The numerical efficiency of the parallelization algorithms is demonstrated for the case studies for the flood predictions of the mountain watersheds of the Ukrainian Carpathian regions. The modeling results is compared with the predictions based on the lumped parameters models.

Earth Observation

NASA Image and Video Library

2013-08-03

Earth observation taken during day pass by an Expedition 36 crew member on board the International Space Station (ISS). Per Twitter message: From southernmost point of orbit over the South Pacific- all clouds seemed to be leading to the South Pole.

Earth Observation

NASA Image and Video Library

2013-07-21

Earth observation taken during night pass by an Expedition 36 crew member on board the International Space Station (ISS). Per Twitter message this is labeled as : Tehran, Iran. Lights along the coast of the Caspian Sea visible through clouds. July 21.

Whistleblower Protection Enhancement Act of 2010

THOMAS, 111th Congress

Sen. Akaka, Daniel K. [D-HI

2009-02-03

Senate - 12/22/2010 Message on House action received in Senate and at desk: House amendments to Senate bill. (All Actions) Tracker: This bill has the status Passed HouseHere are the steps for Status of Legislation:

Earth Observation

NASA Image and Video Library

2014-05-31

Earth Observation taken during a day pass by the Expedition 40 crew aboard the International Space Station (ISS). Folder lists this as: CEO - Arena de Sao Paolo. View used for Twitter message: Cloudy skies over São Paulo Brazil

Performance Analysis of Distributed Object-Oriented Applications

NASA Technical Reports Server (NTRS)

Schoeffler, James D.

1998-01-01

The purpose of this research was to evaluate the efficiency of a distributed simulation architecture which creates individual modules which are made self-scheduling through the use of a message-based communication system used for requesting input data from another module which is the source of that data. To make the architecture as general as possible, the message-based communication architecture was implemented using standard remote object architectures (Common Object Request Broker Architecture (CORBA) and/or Distributed Component Object Model (DCOM)). A series of experiments were run in which different systems are distributed in a variety of ways across multiple computers and the performance evaluated. The experiments were duplicated in each case so that the overhead due to message communication and data transmission can be separated from the time required to actually perform the computational update of a module each iteration. The software used to distribute the modules across multiple computers was developed in the first year of the current grant and was modified considerably to add a message-based communication scheme supported by the DCOM distributed object architecture. The resulting performance was analyzed using a model created during the first year of this grant which predicts the overhead due to CORBA and DCOM remote procedure calls and includes the effects of data passed to and from the remote objects. A report covering the distributed simulation software and the results of the performance experiments has been submitted separately. The above report also discusses possible future work to apply the methodology to dynamically distribute the simulation modules so as to minimize overall computation time.

Interprocess Communication in Highly Distributed Systems - A Workshop Report - 20 to 22, November 1978.

DTIC Science & Technology

1979-12-01

Links between processes can be aLlocated strictLy to controL functions. In fact, the degree of separation of control and data is an important research is...delays or Loss of control messages. Cognoscienti agree that message-passing IPC schemes are equivalent in "power" to schemes which employ shared...THEORETICAL WORK Page 55 SECTION 6 THEORETICAL WORK 6.1 WORKING GRUP JIM REP.OR STRUCTURE of Discussion: Distributed system without central (or any) control

Terrorism Risk Insurance Program Reauthorization Act of 2014

THOMAS, 113th Congress

Sen. Schumer, Charles E. [D-NY

2014-04-10

Senate - 12/11/2014 Message on House action received in Senate and at desk: House amendment to Senate bill. (All Actions) Tracker: This bill has the status Passed HouseHere are the steps for Status of Legislation:

Electronic Message Preservation Act

THOMAS, 111th Congress

Rep. Hodes, Paul W. [D-NH-2

2009-03-09

Senate - 03/18/2010 Received in the Senate and Read twice and referred to the Committee on Homeland Security and Governmental Affairs. (All Actions) Tracker: This bill has the status Passed HouseHere are the steps for Status of Legislation:

Federal Financial Assistance Management Improvement Act of 2009

THOMAS, 111th Congress

Sen. Voinovich, George V. [R-OH

2009-01-22

Senate - 12/15/2009 Message on House action received in Senate and at desk: House amendment to Senate bill. (All Actions) Tracker: This bill has the status Passed HouseHere are the steps for Status of Legislation:

Parallelization of KENO-Va Monte Carlo code

NASA Astrophysics Data System (ADS)

Ramón, Javier; Peña, Jorge

1995-07-01

KENO-Va is a code integrated within the SCALE system developed by Oak Ridge that solves the transport equation through the Monte Carlo Method. It is being used at the Consejo de Seguridad Nuclear (CSN) to perform criticality calculations for fuel storage pools and shipping casks. Two parallel versions of the code: one for shared memory machines and other for distributed memory systems using the message-passing interface PVM have been generated. In both versions the neutrons of each generation are tracked in parallel. In order to preserve the reproducibility of the results in both versions, advanced seeds for random numbers were used. The CONVEX C3440 with four processors and shared memory at CSN was used to implement the shared memory version. A FDDI network of 6 HP9000/735 was employed to implement the message-passing version using proprietary PVM. The speedup obtained was 3.6 in both cases.

Statistical analysis of loopy belief propagation in random fields

NASA Astrophysics Data System (ADS)

Yasuda, Muneki; Kataoka, Shun; Tanaka, Kazuyuki

2015-10-01

Loopy belief propagation (LBP), which is equivalent to the Bethe approximation in statistical mechanics, is a message-passing-type inference method that is widely used to analyze systems based on Markov random fields (MRFs). In this paper, we propose a message-passing-type method to analytically evaluate the quenched average of LBP in random fields by using the replica cluster variation method. The proposed analytical method is applicable to general pairwise MRFs with random fields whose distributions differ from each other and can give the quenched averages of the Bethe free energies over random fields, which are consistent with numerical results. The order of its computational cost is equivalent to that of standard LBP. In the latter part of this paper, we describe the application of the proposed method to Bayesian image restoration, in which we observed that our theoretical results are in good agreement with the numerical results for natural images.

Message-passing-interface-based parallel FDTD investigation on the EM scattering from a 1-D rough sea surface using uniaxial perfectly matched layer absorbing boundary.

PubMed

Li, J; Guo, L-X; Zeng, H; Han, X-B

2009-06-01

A message-passing-interface (MPI)-based parallel finite-difference time-domain (FDTD) algorithm for the electromagnetic scattering from a 1-D randomly rough sea surface is presented. The uniaxial perfectly matched layer (UPML) medium is adopted for truncation of FDTD lattices, in which the finite-difference equations can be used for the total computation domain by properly choosing the uniaxial parameters. This makes the parallel FDTD algorithm easier to implement. The parallel performance with different processors is illustrated for one sea surface realization, and the computation time of the parallel FDTD algorithm is dramatically reduced compared to a single-process implementation. Finally, some numerical results are shown, including the backscattering characteristics of sea surface for different polarization and the bistatic scattering from a sea surface with large incident angle and large wind speed.

Simple, efficient allocation of modelling runs on heterogeneous clusters with MPI

USGS Publications Warehouse

Donato, David I.

2017-01-01

In scientific modelling and computation, the choice of an appropriate method for allocating tasks for parallel processing depends on the computational setting and on the nature of the computation. The allocation of independent but similar computational tasks, such as modelling runs or Monte Carlo trials, among the nodes of a heterogeneous computational cluster is a special case that has not been specifically evaluated previously. A simulation study shows that a method of on-demand (that is, worker-initiated) pulling from a bag of tasks in this case leads to reliably short makespans for computational jobs despite heterogeneity both within and between cluster nodes. A simple reference implementation in the C programming language with the Message Passing Interface (MPI) is provided.

SBML-PET-MPI: a parallel parameter estimation tool for Systems Biology Markup Language based models.

PubMed

Zi, Zhike

2011-04-01

Parameter estimation is crucial for the modeling and dynamic analysis of biological systems. However, implementing parameter estimation is time consuming and computationally demanding. Here, we introduced a parallel parameter estimation tool for Systems Biology Markup Language (SBML)-based models (SBML-PET-MPI). SBML-PET-MPI allows the user to perform parameter estimation and parameter uncertainty analysis by collectively fitting multiple experimental datasets. The tool is developed and parallelized using the message passing interface (MPI) protocol, which provides good scalability with the number of processors. SBML-PET-MPI is freely available for non-commercial use at http://www.bioss.uni-freiburg.de/cms/sbml-pet-mpi.html or http://sites.google.com/site/sbmlpetmpi/.

Autoplan: A self-processing network model for an extended blocks world planning environment

NASA Technical Reports Server (NTRS)

Dautrechy, C. Lynne; Reggia, James A.; Mcfadden, Frank

1990-01-01

Self-processing network models (neural/connectionist models, marker passing/message passing networks, etc.) are currently undergoing intense investigation for a variety of information processing applications. These models are potentially very powerful in that they support a large amount of explicit parallel processing, and they cleanly integrate high level and low level information processing. However they are currently limited by a lack of understanding of how to apply them effectively in many application areas. The formulation of self-processing network methods for dynamic, reactive planning is studied. The long-term goal is to formulate robust, computationally effective information processing methods for the distributed control of semiautonomous exploration systems, e.g., the Mars Rover. The current research effort is focusing on hierarchical plan generation, execution and revision through local operations in an extended blocks world environment. This scenario involves many challenging features that would be encountered in a real planning and control environment: multiple simultaneous goals, parallel as well as sequential action execution, action sequencing determined not only by goals and their interactions but also by limited resources (e.g., three tasks, two acting agents), need to interpret unanticipated events and react appropriately through replanning, etc.

Vascular system modeling in parallel environment - distributed and shared memory approaches

PubMed Central

Jurczuk, Krzysztof; Kretowski, Marek; Bezy-Wendling, Johanne

2011-01-01

The paper presents two approaches in parallel modeling of vascular system development in internal organs. In the first approach, new parts of tissue are distributed among processors and each processor is responsible for perfusing its assigned parts of tissue to all vascular trees. Communication between processors is accomplished by passing messages and therefore this algorithm is perfectly suited for distributed memory architectures. The second approach is designed for shared memory machines. It parallelizes the perfusion process during which individual processing units perform calculations concerning different vascular trees. The experimental results, performed on a computing cluster and multi-core machines, show that both algorithms provide a significant speedup. PMID:21550891

Porting Gravitational Wave Signal Extraction to Parallel Virtual Machine (PVM)

NASA Technical Reports Server (NTRS)

Thirumalainambi, Rajkumar; Thompson, David E.; Redmon, Jeffery

2009-01-01

Laser Interferometer Space Antenna (LISA) is a planned NASA-ESA mission to be launched around 2012. The Gravitational Wave detection is fundamentally the determination of frequency, source parameters, and waveform amplitude derived in a specific order from the interferometric time-series of the rotating LISA spacecrafts. The LISA Science Team has developed a Mock LISA Data Challenge intended to promote the testing of complicated nested search algorithms to detect the 100-1 millihertz frequency signals at amplitudes of 10E-21. However, it has become clear that, sequential search of the parameters is very time consuming and ultra-sensitive; hence, a new strategy has been developed. Parallelization of existing sequential search algorithms of Gravitational Wave signal identification consists of decomposing sequential search loops, beginning with outermost loops and working inward. In this process, the main challenge is to detect interdependencies among loops and partitioning the loops so as to preserve concurrency. Existing parallel programs are based upon either shared memory or distributed memory paradigms. In PVM, master and node programs are used to execute parallelization and process spawning. The PVM can handle process management and process addressing schemes using a virtual machine configuration. The task scheduling and the messaging and signaling can be implemented efficiently for the LISA Gravitational Wave search process using a master and 6 nodes. This approach is accomplished using a server that is available at NASA Ames Research Center, and has been dedicated to the LISA Data Challenge Competition. Historically, gravitational wave and source identification parameters have taken around 7 days in this dedicated single thread Linux based server. Using PVM approach, the parameter extraction problem can be reduced to within a day. The low frequency computation and a proxy signal-to-noise ratio are calculated in separate nodes that are controlled by the master using message and vector of data passing. The message passing among nodes follows a pattern of synchronous and asynchronous send-and-receive protocols. The communication model and the message buffers are allocated dynamically to address rapid search of gravitational wave source information in the Mock LISA data sets.

Evaluation of a high visibility enforcement project focused on passenger vehicles interacting with commercial vehicles.

PubMed

Thomas, F Dennis; Blomberg, Richard D; Peck, Raymond C; Cosgrove, Linda A; Salzberg, Philip M

2008-01-01

In 2004, Washington State applied NHTSA's High Visibility Enforcement model used in the Click It or Ticket seat belt campaign in an attempt to reduce unsafe driving behaviors around commercial motor vehicles (CMVs). The program was called Ticketing Aggressive Cars and Trucks (TACT). This paper details the methods used to evaluate the program's effectiveness and the results of the evaluation. Four high-crash interstate highway corridors, each approximately 25 miles in length, were selected. Two of these corridors received TACT media messages and increased enforcement over an 18-month period while two comparison corridors did not receive any increased media or enforcement. A total of 4,737 contacts were made with drivers during the two enforcement waves, and 72% of these contacts led to a citation. Drivers at the intervention sites who said they saw or heard any of the TACT messages increased from 17.7% in the pre period to a high of 67.3% in the post periods. Drivers at the intervention sites also reported increased exposure to the core message of leaving more space when passing trucks (14% pre to 40% post period). The percentage of drivers who said they leave more room when passing trucks than when passing cars rose from 16% in the pre period to 24% in the post period at the intervention sites, while comparison sites showed no change. Over 150 hours of video recorded by law enforcement officers in unmarked vehicles were utilized to examine violation rates and severity of violations before and after the intervention campaigns. Statistical analyses showed that violation rates were reduced significantly at the intervention sites (between 23% and 46%), while remaining constant at the comparison sites. Analyses of the video data also showed that the seriousness of the residual violations at the intervention sites decreased. Overall, the evaluation results provide a consistent picture of the effectiveness of the TACT pilot project. Success was demonstrated at every step - messages were received and understood, knowledge was changed in the intended direction, self reported driving behavior around large trucks improved, and observed driving behaviors confirmed the self reports. After this initial success in Washington State, the TACT model will continue to be implemented and evaluated by FMCSA in an attempt to validate the program. Based on the results of this study and the consistent positive results found for other sTEP projects, it is likely that TACT will show continued success in a variety of settings and will help reduce the number and severity of crashes involving CMVs. Future research should attempt to use many of the methods described here to further validate the methods for not only evaluations of TACT programs, but also for any other highway safety programs that require measurements of the program's effectiveness.

Satellite telemetry: performance of animal-tracking systems

USGS Publications Warehouse

Keating, Kim A.; Brewster, Wayne G.; Key, Carl H.

1991-01-01

t: We used 10 Telonics ST-3 platform transmitter terminals (PTT's) configured for wolves and ungulates to examine the performance of the Argos satellite telemetry system. Under near-optimal conditions, 68 percentile errors for location qualities (NQ) 1, 2, and 3 were 1,188, 903, and 361 m, respectively. Errors (rE) exceeded expected values for NQ = 2 and 3, varied greatly among PTT's, increased as the difference (HE) between the estimated and actual PTT elevations increased, and were correlated nonlinearly with maximum satellite pass height (P,). We present a model of the relationships among rE, HE, and PH. Errors were bimodally distributed along the east-west axis and tended to occur away from the satellite when HE was positive. A southeasterly bias increased with HE, probably due to the particular distribution of satellite passes and effects of HE on rE. Under near-optimal conditions, 21 sensor message was received for up to 64% of available (PH, 50) satellite passes, and a location (NQ 2 1) was calculated for up to 63% of such passes. Sampling frequencies of sensor and location data declined 13 and 70%, respectively, for PTT's in a valley bottom and 65 and 86%, respectively, for PTT's on animals that were in valley bottoms. Sampling frequencies were greater for ungulate than for wolf collars.

MPI_XSTAR: MPI-based parallelization of XSTAR program

NASA Astrophysics Data System (ADS)

Danehkar, A.

2017-12-01

MPI_XSTAR parallelizes execution of multiple XSTAR runs using Message Passing Interface (MPI). XSTAR (ascl:9910.008), part of the HEASARC's HEAsoft (ascl:1408.004) package, calculates the physical conditions and emission spectra of ionized gases. MPI_XSTAR invokes XSTINITABLE from HEASoft to generate a job list of XSTAR commands for given physical parameters. The job list is used to make directories in ascending order, where each individual XSTAR is spawned on each processor and outputs are saved. HEASoft's XSTAR2TABLE program is invoked upon the contents of each directory in order to produce table model FITS files for spectroscopy analysis tools.

Message passing with queues and channels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dozsa, Gabor J; Heidelberger, Philip; Kumar, Sameer

In an embodiment, a send thread receives an identifier that identifies a destination node and a pointer to data. The send thread creates a first send request in response to the receipt of the identifier and the data pointer. The send thread selects a selected channel from among a plurality of channels. The selected channel comprises a selected hand-off queue and an identification of a selected message unit. Each of the channels identifies a different message unit. The selected hand-off queue is randomly accessible. If the selected hand-off queue contains an available entry, the send thread adds the first sendmore » request to the selected hand-off queue. If the selected hand-off queue does not contain an available entry, the send thread removes a second send request from the selected hand-off queue and sends the second send request to the selected message unit.« less

Scalable Optical-Fiber Communication Networks

NASA Technical Reports Server (NTRS)

Chow, Edward T.; Peterson, John C.

1993-01-01

Scalable arbitrary fiber extension network (SAFEnet) is conceptual fiber-optic communication network passing digital signals among variety of computers and input/output devices at rates from 200 Mb/s to more than 100 Gb/s. Intended for use with very-high-speed computers and other data-processing and communication systems in which message-passing delays must be kept short. Inherent flexibility makes it possible to match performance of network to computers by optimizing configuration of interconnections. In addition, interconnections made redundant to provide tolerance to faults.

Domestic Minor Sex Trafficking Deterrence and Victims Support Act of 2010

THOMAS, 111th Congress

Sen. Wyden, Ron [D-OR

2009-12-22

Senate - 12/21/2010 Message on House action received in Senate and at desk: House amendment to Senate bill. (All Actions) Tracker: This bill has the status Passed HouseHere are the steps for Status of Legislation:

Chaos synchronization communication using extremely unsymmetrical bidirectional injections.

PubMed

Zhang, Wei Li; Pan, Wei; Luo, Bin; Zou, Xi Hua; Wang, Meng Yao; Zhou, Zhi

2008-02-01

Chaos synchronization and message transmission between two semiconductor lasers with extremely unsymmetrical bidirectional injections (EUBIs) are discussed. By using EUBIs, synchronization is realized through injection locking. Numerical results show that if the laser subjected to strong injection serves as the receiver, chaos pass filtering (CPF) of the system is similar to that of unidirectional coupled systems. Moreover, if the other laser serves as the receiver, a stronger CPF can be obtained. Finally, we demonstrate that messages can be extracted successfully from either of the two transmission directions of the system.

Automation Framework for Flight Dynamics Products Generation

NASA Technical Reports Server (NTRS)

Wiegand, Robert E.; Esposito, Timothy C.; Watson, John S.; Jun, Linda; Shoan, Wendy; Matusow, Carla

2010-01-01

XFDS provides an easily adaptable automation platform. To date it has been used to support flight dynamics operations. It coordinates the execution of other applications such as Satellite TookKit, FreeFlyer, MATLAB, and Perl code. It provides a mechanism for passing messages among a collection of XFDS processes, and allows sending and receiving of GMSEC messages. A unified and consistent graphical user interface (GUI) is used for the various tools. Its automation configuration is stored in text files, and can be edited either directly or using the GUI.

Toward a humanistic model in health communication.

PubMed

Werder, Olaf

2017-03-01

Since the key to effective health communication lies in its ability to communicate well, some of its core problems are those that relate to the sharing of meaning between communicators. In elaborating on these problems, this paper offers two key propositions: one, health communication has to pass through the filter of a particular world view that creates a discrepancy between expected and actual message reception and response. Two, the assumption of a rational human actor made implicitly by most health psychological models is a contestable issue, as many times message recipients do not follow a cognitive judgment process. The phenomenon of resisting health messages by reasonable people asks the question whether we ought to rethink our adherence to a particular vision of human health as many times the adverse reaction to behaviour modification occurs as the result of a particular dialogical or discursive situation. At the same time, most motivational decisions in people's daily routines are automatic and use a concept known as self-identity to give stability to their behaviour patterns. Finally, health communication as part of organised government practices adheres to predominant value perspectives within health promotion practice that affect the manner in which health issues become problematised. This paper proposes a humanistic model that aims to pay attention to the intricacies of human communication by addressing all of the above problems in turn. It interprets the sharing of meaning element in human communication and addresses the question of how the idea of health is created through discourse. As such, it offers a complementary and constructive paradigm and set of approaches to understand health, its meanings and communication.

Disaster Relief Appropriations Act, 2013

THOMAS, 112th Congress

Rep. Rogers, Harold [R-KY-5

2011-02-11

Senate - 12/30/2012 Message on Senate action sent to the House. (All Actions) Notes: This bill was for a time the Senate legislative vehicle for Hurricane Sandy supplemental appropriations. Tracker: This bill has the status Passed SenateHere are the steps for Status of Legislation:

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shipman, Galen M.

These are the slides for a presentation on programming models in HPC, at the Los Alamos National Laboratory's Parallel Computing Summer School. The following topics are covered: Flynn's Taxonomy of computer architectures; single instruction single data; single instruction multiple data; multiple instruction multiple data; address space organization; definition of Trinity (Intel Xeon-Phi is a MIMD architecture); single program multiple data; multiple program multiple data; ExMatEx workflow overview; definition of a programming model, programming languages, runtime systems; programming model and environments; MPI (Message Passing Interface); OpenMP; Kokkos (Performance Portable Thread-Parallel Programming Model); Kokkos abstractions, patterns, policies, and spaces; RAJA, a systematicmore » approach to node-level portability and tuning; overview of the Legion Programming Model; mapping tasks and data to hardware resources; interoperability: supporting task-level models; Legion S3D execution and performance details; workflow, integration of external resources into the programming model.« less

Interactive Supercomputing’s Star-P Platform

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edelman, Alan; Husbands, Parry; Leibman, Steve

2006-09-19

The thesis of this extended abstract is simple. High productivity comes from high level infrastructures. To measure this, we introduce a methodology that goes beyond the tradition of timing software in serial and tuned parallel modes. We perform a classroom productivity study involving 29 students who have written a homework exercise in a low level language (MPI message passing) and a high level language (Star-P with MATLAB client). Our conclusions indicate what perhaps should be of little surprise: (1) the high level language is always far easier on the students than the low level language. (2) The early versions ofmore » the high level language perform inadequately compared to the tuned low level language, but later versions substantially catch up. Asymptotically, the analogy must hold that message passing is to high level language parallel programming as assembler is to high level environments such as MATLAB, Mathematica, Maple, or even Python. We follow the Kepner method that correctly realizes that traditional speedup numbers without some discussion of the human cost of reaching these numbers can fail to reflect the true human productivity cost of high performance computing. Traditional data compares low level message passing with serial computation. With the benefit of a high level language system in place, in our case Star-P running with MATLAB client, and with the benefit of a large data pool: 29 students, each running the same code ten times on three evolutions of the same platform, we can methodically demonstrate the productivity gains. To date we are not aware of any high level system as extensive and interoperable as Star-P, nor are we aware of an experiment of this kind performed with this volume of data.« less

Applications Performance Under MPL and MPI on NAS IBM SP2

NASA Technical Reports Server (NTRS)

Saini, Subhash; Simon, Horst D.; Lasinski, T. A. (Technical Monitor)

1994-01-01

On July 5, 1994, an IBM Scalable POWER parallel System (IBM SP2) with 64 nodes, was installed at the Numerical Aerodynamic Simulation (NAS) Facility Each node of NAS IBM SP2 is a "wide node" consisting of a RISC 6000/590 workstation module with a clock of 66.5 MHz which can perform four floating point operations per clock with a peak performance of 266 Mflop/s. By the end of 1994, 64 nodes of IBM SP2 will be upgraded to 160 nodes with a peak performance of 42.5 Gflop/s. An overview of the IBM SP2 hardware is presented. The basic understanding of architectural details of RS 6000/590 will help application scientists the porting, optimizing, and tuning of codes from other machines such as the CRAY C90 and the Paragon to the NAS SP2. Optimization techniques such as quad-word loading, effective utilization of two floating point units, and data cache optimization of RS 6000/590 is illustrated, with examples giving performance gains at each optimization step. The conversion of codes using Intel's message passing library NX to codes using native Message Passing Library (MPL) and the Message Passing Interface (NMI) library available on the IBM SP2 is illustrated. In particular, we will present the performance of Fast Fourier Transform (FFT) kernel from NAS Parallel Benchmarks (NPB) under MPL and MPI. We have also optimized some of Fortran BLAS 2 and BLAS 3 routines, e.g., the optimized Fortran DAXPY runs at 175 Mflop/s and optimized Fortran DGEMM runs at 230 Mflop/s per node. The performance of the NPB (Class B) on the IBM SP2 is compared with the CRAY C90, Intel Paragon, TMC CM-5E, and the CRAY T3D.

Enabling Energy Saving Innovations Act

THOMAS, 112th Congress

Rep. Aderholt, Robert B. [R-AL-4

2012-04-26

Senate - 09/24/2012 Message on Senate action sent to the House. (All Actions) Notes: For further action, see H.R.6582, which became Public Law 112-210 on 12/18/2012. Tracker: This bill has the status Passed SenateHere are the steps for Status of Legislation:

Interstate Recognition of Notarizations Act of 2010

THOMAS, 111th Congress

Rep. Aderholt, Robert B. [R-AL-4

2009-10-14

House - 11/17/2010 On motion to refer the bill and the accompanying veto message to the Committee on the Judiciary. Agreed to without objection. (All Actions) Tracker: This bill has the status Failed to pass over vetoHere are the steps for Status of Legislation:

Communication Studies of DMP and SMP Machines

NASA Technical Reports Server (NTRS)

Sohn, Andrew; Biswas, Rupak; Chancellor, Marisa K. (Technical Monitor)

1997-01-01

Understanding the interplay between machines and problems is key to obtaining high performance on parallel machines. This paper investigates the interplay between programming paradigms and communication capabilities of parallel machines. In particular, we explicate the communication capabilities of the IBM SP-2 distributed-memory multiprocessor and the SGI PowerCHALLENGEarray symmetric multiprocessor. Two benchmark problems of bitonic sorting and Fast Fourier Transform are selected for experiments. Communication-efficient algorithms are developed to exploit the overlapping capabilities of the machines. Programs are written in Message-Passing Interface for portability and identical codes are used for both machines. Various data sizes and message sizes are used to test the machines' communication capabilities. Experimental results indicate that the communication performance of the multiprocessors are consistent with the size of messages. The SP-2 is sensitive to message size but yields a much higher communication overlapping because of the communication co-processor. The PowerCHALLENGEarray is not highly sensitive to message size and yields a low communication overlapping. Bitonic sorting yields lower performance compared to FFT due to a smaller computation-to-communication ratio.

Approximate message passing for nonconvex sparse regularization with stability and asymptotic analysis

NASA Astrophysics Data System (ADS)

Sakata, Ayaka; Xu, Yingying

2018-03-01

We analyse a linear regression problem with nonconvex regularization called smoothly clipped absolute deviation (SCAD) under an overcomplete Gaussian basis for Gaussian random data. We propose an approximate message passing (AMP) algorithm considering nonconvex regularization, namely SCAD-AMP, and analytically show that the stability condition corresponds to the de Almeida-Thouless condition in spin glass literature. Through asymptotic analysis, we show the correspondence between the density evolution of SCAD-AMP and the replica symmetric (RS) solution. Numerical experiments confirm that for a sufficiently large system size, SCAD-AMP achieves the optimal performance predicted by the replica method. Through replica analysis, a phase transition between replica symmetric and replica symmetry breaking (RSB) region is found in the parameter space of SCAD. The appearance of the RS region for a nonconvex penalty is a significant advantage that indicates the region of smooth landscape of the optimization problem. Furthermore, we analytically show that the statistical representation performance of the SCAD penalty is better than that of \

Mapping a battlefield simulation onto message-passing parallel architectures

NASA Technical Reports Server (NTRS)

Nicol, David M.

1987-01-01

Perhaps the most critical problem in distributed simulation is that of mapping: without an effective mapping of workload to processors the speedup potential of parallel processing cannot be realized. Mapping a simulation onto a message-passing architecture is especially difficult when the computational workload dynamically changes as a function of time and space; this is exactly the situation faced by battlefield simulations. This paper studies an approach where the simulated battlefield domain is first partitioned into many regions of equal size; typically there are more regions than processors. The regions are then assigned to processors; a processor is responsible for performing all simulation activity associated with the regions. The assignment algorithm is quite simple and attempts to balance load by exploiting locality of workload intensity. The performance of this technique is studied on a simple battlefield simulation implemented on the Flex/32 multiprocessor. Measurements show that the proposed method achieves reasonable processor efficiencies. Furthermore, the method shows promise for use in dynamic remapping of the simulation.

Applications and development of communication models for the touchstone GAMMA and DELTA prototypes

NASA Technical Reports Server (NTRS)

Seidel, Steven R.

1993-01-01

The goal of this project was to develop models of the interconnection networks of the Intel iPSC/860 and DELTA multicomputers to guide the design of efficient algorithms for interprocessor communication in problems that commonly occur in CFD codes and other applications. Interprocessor communication costs of codes for message-passing architectures such as the iPSC/860 and DELTA significantly affect the level of performance that can be obtained from those machines. This project addressed several specific problems in the achievement of efficient communication on the Intel iPSC/860 hypercube and DELTA mesh. In particular, an efficient global processor synchronization algorithm was developed for the iPSC/860 and numerous broadcast algorithms were designed for the DELTA.

PCTDSE: A parallel Cartesian-grid-based TDSE solver for modeling laser-atom interactions

NASA Astrophysics Data System (ADS)

Fu, Yongsheng; Zeng, Jiaolong; Yuan, Jianmin

2017-01-01

We present a parallel Cartesian-grid-based time-dependent Schrödinger equation (TDSE) solver for modeling laser-atom interactions. It can simulate the single-electron dynamics of atoms in arbitrary time-dependent vector potentials. We use a split-operator method combined with fast Fourier transforms (FFT), on a three-dimensional (3D) Cartesian grid. Parallelization is realized using a 2D decomposition strategy based on the Message Passing Interface (MPI) library, which results in a good parallel scaling on modern supercomputers. We give simple applications for the hydrogen atom using the benchmark problems coming from the references and obtain repeatable results. The extensions to other laser-atom systems are straightforward with minimal modifications of the source code.

National Combustion Code Parallel Performance Enhancements

NASA Technical Reports Server (NTRS)

Quealy, Angela; Benyo, Theresa (Technical Monitor)

2002-01-01

The National Combustion Code (NCC) is being developed by an industry-government team for the design and analysis of combustion systems. The unstructured grid, reacting flow code uses a distributed memory, message passing model for its parallel implementation. The focus of the present effort has been to improve the performance of the NCC code to meet combustor designer requirements for model accuracy and analysis turnaround time. Improving the performance of this code contributes significantly to the overall reduction in time and cost of the combustor design cycle. This report describes recent parallel processing modifications to NCC that have improved the parallel scalability of the code, enabling a two hour turnaround for a 1.3 million element fully reacting combustion simulation on an SGI Origin 2000.

Application of decentralized cooperative problem solving in dynamic flexible scheduling

NASA Astrophysics Data System (ADS)

Guan, Zai-Lin; Lei, Ming; Wu, Bo; Wu, Ya; Yang, Shuzi

1995-08-01

The object of this study is to discuss an intelligent solution to the problem of task-allocation in shop floor scheduling. For this purpose, the technique of distributed artificial intelligence (DAI) is applied. Intelligent agents (IAs) are used to realize decentralized cooperation, and negotiation is realized by using message passing based on the contract net model. Multiple agents, such as manager agents, workcell agents, and workstation agents, make game-like decisions based on multiple criteria evaluations. This procedure of decentralized cooperative problem solving makes local scheduling possible. And by integrating such multiple local schedules, dynamic flexible scheduling for the whole shop floor production can be realized.

An MPA-IO interface to HPSS

NASA Technical Reports Server (NTRS)

Jones, Terry; Mark, Richard; Martin, Jeanne; May, John; Pierce, Elsie; Stanberry, Linda

1996-01-01

This paper describes an implementation of the proposed MPI-IO (Message Passing Interface - Input/Output) standard for parallel I/O. Our system uses third-party transfer to move data over an external network between the processors where it is used and the I/O devices where it resides. Data travels directly from source to destination, without the need for shuffling it among processors or funneling it through a central node. Our distributed server model lets multiple compute nodes share the burden of coordinating data transfers. The system is built on the High Performance Storage System (HPSS), and a prototype version runs on a Meiko CS-2 parallel computer.

Kingman and Heritage Islands Act of 2009

THOMAS, 111th Congress

Rep. Norton, Eleanor Holmes [D-DC-At Large

2009-04-23

Senate - 09/28/2010 Message on Senate action sent to the House. (All Actions) Notes: For further action, see H.R.6278, which became Public Law 111-328 on 12/22/2010. Tracker: This bill has the status Passed SenateHere are the steps for Status of Legislation:

Distance Learning and Public School Finance.

ERIC Educational Resources Information Center

Monahan, Brian; Wimber, Charles

This discussion of the application of computers and telecommunications technology to distance learning begins by describing a workstation equipped to produce "lessonware" in such formats as audiocassettes, videocassettes, diskettes, and voice messages. Such workstations would be located in classrooms equipped with two-way reverse passes to a cable…

Reducing Flight Delays Act of 2013

THOMAS, 113th Congress

Sen. Collins, Susan M. [R-ME

2013-04-25

Senate - 04/30/2013 Message on Senate action sent to the House. (All Actions) Notes: For further action, see H.R.1765, which became Public Law 113-9 on 5/1/2013. Tracker: This bill has the status Passed SenateHere are the steps for Status of Legislation:

Temporary Bankruptcy Judgeships Extension Act of 2011

THOMAS, 112th Congress

Rep. Smith, Lamar [R-TX-21

2011-03-10

Senate - 04/23/2012 Message on Senate action sent to the House. (All Actions) Notes: For further action, see H.R.4967, which became Public Law 112-121 on 5/25/2012. Tracker: This bill has the status Passed SenateHere are the steps for Status of Legislation:

Six degrees of depolarization. Comment on "Network science of biological systems at different scales: A review" by Marko Gosak et al.

NASA Astrophysics Data System (ADS)

Wedgwood, Kyle C. A.; Satin, Leslie S.

2018-03-01

In 1967, the social psychologist Stanley Milgram asked how many intermediates would be required for a letter from participants in various U.S. states to be received by a contact in Boston, given that participants were given only basic information about the contact, and were instructed only to pass along the message to someone that might know the intended recipient [27]. The surprising answer was that, in spite of the social and geographical distances covered, on average, only 6 people were required for the message to reach its intended target.

A distributed infrastructure for publishing VO services: an implementation

NASA Astrophysics Data System (ADS)

Cepparo, Francesco; Scagnetto, Ivan; Molinaro, Marco; Smareglia, Riccardo

2016-07-01

This contribution describes both the design and the implementation details of a new solution for publishing VO services, enlightening its maintainable, distributed, modular and scalable architecture. Indeed, the new publisher is multithreaded and multiprocess. Multiple instances of the modules can run on different machines to ensure high performance and high availability, and this will be true both for the interface modules of the services and the back end data access ones. The system uses message passing to let its components communicate through an AMQP message broker that can itself be distributed to provide better scalability and availability.

Symbolically Modeling Concurrent MCAPI Executions

NASA Technical Reports Server (NTRS)

Fischer, Topher; Mercer, Eric; Rungta, Neha

2011-01-01

Improper use of Inter-Process Communication (IPC) within concurrent systems often creates data races which can lead to bugs that are challenging to discover. Techniques that use Satisfiability Modulo Theories (SMT) problems to symbolically model possible executions of concurrent software have recently been proposed for use in the formal verification of software. In this work we describe a new technique for modeling executions of concurrent software that use a message passing API called MCAPI. Our technique uses an execution trace to create an SMT problem that symbolically models all possible concurrent executions and follows the same sequence of conditional branch outcomes as the provided execution trace. We check if there exists a satisfying assignment to the SMT problem with respect to specific safety properties. If such an assignment exists, it provides the conditions that lead to the violation of the property. We show how our method models behaviors of MCAPI applications that are ignored in previously published techniques.

WinHPC System Programming | High-Performance Computing | NREL

Science.gov Websites

Programming WinHPC System Programming Learn how to build and run an MPI (message passing interface (mpi.h) and library (msmpi.lib) are. To build from the command line, run... Start > Intel Software Development Tools > Intel C++ Compiler Professional... > C++ Build Environment for applications running

Testing New Programming Paradigms with NAS Parallel Benchmarks

NASA Technical Reports Server (NTRS)

Jin, H.; Frumkin, M.; Schultz, M.; Yan, J.

2000-01-01

Over the past decade, high performance computing has evolved rapidly, not only in hardware architectures but also with increasing complexity of real applications. Technologies have been developing to aim at scaling up to thousands of processors on both distributed and shared memory systems. Development of parallel programs on these computers is always a challenging task. Today, writing parallel programs with message passing (e.g. MPI) is the most popular way of achieving scalability and high performance. However, writing message passing programs is difficult and error prone. Recent years new effort has been made in defining new parallel programming paradigms. The best examples are: HPF (based on data parallelism) and OpenMP (based on shared memory parallelism). Both provide simple and clear extensions to sequential programs, thus greatly simplify the tedious tasks encountered in writing message passing programs. HPF is independent of memory hierarchy, however, due to the immaturity of compiler technology its performance is still questionable. Although use of parallel compiler directives is not new, OpenMP offers a portable solution in the shared-memory domain. Another important development involves the tremendous progress in the internet and its associated technology. Although still in its infancy, Java promisses portability in a heterogeneous environment and offers possibility to "compile once and run anywhere." In light of testing these new technologies, we implemented new parallel versions of the NAS Parallel Benchmarks (NPBs) with HPF and OpenMP directives, and extended the work with Java and Java-threads. The purpose of this study is to examine the effectiveness of alternative programming paradigms. NPBs consist of five kernels and three simulated applications that mimic the computation and data movement of large scale computational fluid dynamics (CFD) applications. We started with the serial version included in NPB2.3. Optimization of memory and cache usage was applied to several benchmarks, noticeably BT and SP, resulting in better sequential performance. In order to overcome the lack of an HPF performance model and guide the development of the HPF codes, we employed an empirical performance model for several primitives found in the benchmarks. We encountered a few limitations of HPF, such as lack of supporting the "REDISTRIBUTION" directive and no easy way to handle irregular computation. The parallelization with OpenMP directives was done at the outer-most loop level to achieve the largest granularity. The performance of six HPF and OpenMP benchmarks is compared with their MPI counterparts for the Class-A problem size in the figure in next page. These results were obtained on an SGI Origin2000 (195MHz) with MIPSpro-f77 compiler 7.2.1 for OpenMP and MPI codes and PGI pghpf-2.4.3 compiler with MPI interface for HPF programs.

Information processing in the CNS: a supramolecular chemistry?

PubMed

Tozzi, Arturo

2015-10-01

How does central nervous system process information? Current theories are based on two tenets: (a) information is transmitted by action potentials, the language by which neurons communicate with each other-and (b) homogeneous neuronal assemblies of cortical circuits operate on these neuronal messages where the operations are characterized by the intrinsic connectivity among neuronal populations. In this view, the size and time course of any spike is stereotypic and the information is restricted to the temporal sequence of the spikes; namely, the "neural code". However, an increasing amount of novel data point towards an alternative hypothesis: (a) the role of neural code in information processing is overemphasized. Instead of simply passing messages, action potentials play a role in dynamic coordination at multiple spatial and temporal scales, establishing network interactions across several levels of a hierarchical modular architecture, modulating and regulating the propagation of neuronal messages. (b) Information is processed at all levels of neuronal infrastructure from macromolecules to population dynamics. For example, intra-neuronal (changes in protein conformation, concentration and synthesis) and extra-neuronal factors (extracellular proteolysis, substrate patterning, myelin plasticity, microbes, metabolic status) can have a profound effect on neuronal computations. This means molecular message passing may have cognitive connotations. This essay introduces the concept of "supramolecular chemistry", involving the storage of information at the molecular level and its retrieval, transfer and processing at the supramolecular level, through transitory non-covalent molecular processes that are self-organized, self-assembled and dynamic. Finally, we note that the cortex comprises extremely heterogeneous cells, with distinct regional variations, macromolecular assembly, receptor repertoire and intrinsic microcircuitry. This suggests that every neuron (or group of neurons) embodies different molecular information that hands an operational effect on neuronal computation.

Ice-sheet modelling accelerated by graphics cards

NASA Astrophysics Data System (ADS)

Brædstrup, Christian Fredborg; Damsgaard, Anders; Egholm, David Lundbek

2014-11-01

Studies of glaciers and ice sheets have increased the demand for high performance numerical ice flow models over the past decades. When exploring the highly non-linear dynamics of fast flowing glaciers and ice streams, or when coupling multiple flow processes for ice, water, and sediment, researchers are often forced to use super-computing clusters. As an alternative to conventional high-performance computing hardware, the Graphical Processing Unit (GPU) is capable of massively parallel computing while retaining a compact design and low cost. In this study, we present a strategy for accelerating a higher-order ice flow model using a GPU. By applying the newest GPU hardware, we achieve up to 180× speedup compared to a similar but serial CPU implementation. Our results suggest that GPU acceleration is a competitive option for ice-flow modelling when compared to CPU-optimised algorithms parallelised by the OpenMP or Message Passing Interface (MPI) protocols.

Mars Global Reference Atmospheric Model (Mars-GRAM 3.34): Programmer's Guide

NASA Technical Reports Server (NTRS)

Justus, C. G.; James, Bonnie F.; Johnson, Dale L.

1996-01-01

This is a programmer's guide for the Mars Global Reference Atmospheric Model (Mars-GRAM 3.34). Included are a brief history and review of the model since its origin in 1988 and a technical discussion of recent additions and modifications. Examples of how to run both the interactive and batch (subroutine) forms are presented. Instructions are provided on how to customize output of the model for various parameters of the Mars atmosphere. Detailed descriptions are given of the main driver programs, subroutines, and associated computational methods. Lists and descriptions include input, output, and local variables in the programs. These descriptions give a summary of program steps and 'map' of calling relationships among the subroutines. Definitions are provided for the variables passed between subroutines through common lists. Explanations are provided for all diagnostic and progress messages generated during execution of the program. A brief outline of future plans for Mars-GRAM is also presented.

Increasing the Operational Value of Event Messages

NASA Technical Reports Server (NTRS)

Li, Zhenping; Savkli, Cetin; Smith, Dan

2003-01-01

Assessing the health of a space mission has traditionally been performed using telemetry analysis tools. Parameter values are compared to known operational limits and are plotted over various time periods. This presentation begins with the notion that there is an incredible amount of untapped information contained within the mission s event message logs. Through creative advancements in message handling tools, the event message logs can be used to better assess spacecraft and ground system status and to highlight and report on conditions not readily apparent when messages are evaluated one-at-a-time during a real-time pass. Work in this area is being funded as part of a larger NASA effort at the Goddard Space Flight Center to create component-based, middleware-based, standards-based general purpose ground system architecture referred to as GMSEC - the GSFC Mission Services Evolution Center. The new capabilities and operational concepts for event display, event data analyses and data mining are being developed by Lockheed Martin and the new subsystem has been named GREAT - the GMSEC Reusable Event Analysis Toolkit. Planned for use on existing and future missions, GREAT has the potential to increase operational efficiency in areas of problem detection and analysis, general status reporting, and real-time situational awareness.

Decaf: Decoupled Dataflows for In Situ High-Performance Workflows

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dreher, M.; Peterka, T.

Decaf is a dataflow system for the parallel communication of coupled tasks in an HPC workflow. The dataflow can perform arbitrary data transformations ranging from simply forwarding data to complex data redistribution. Decaf does this by allowing the user to allocate resources and execute custom code in the dataflow. All communication through the dataflow is efficient parallel message passing over MPI. The runtime for calling tasks is entirely message-driven; Decaf executes a task when all messages for the task have been received. Such a messagedriven runtime allows cyclic task dependencies in the workflow graph, for example, to enact computational steeringmore » based on the result of downstream tasks. Decaf includes a simple Python API for describing the workflow graph. This allows Decaf to stand alone as a complete workflow system, but Decaf can also be used as the dataflow layer by one or more other workflow systems to form a heterogeneous task-based computing environment. In one experiment, we couple a molecular dynamics code with a visualization tool using the FlowVR and Damaris workflow systems and Decaf for the dataflow. In another experiment, we test the coupling of a cosmology code with Voronoi tessellation and density estimation codes using MPI for the simulation, the DIY programming model for the two analysis codes, and Decaf for the dataflow. Such workflows consisting of heterogeneous software infrastructures exist because components are developed separately with different programming models and runtimes, and this is the first time that such heterogeneous coupling of diverse components was demonstrated in situ on HPC systems.« less

A no-key-exchange secure image sharing scheme based on Shamir's three-pass cryptography protocol and the multiple-parameter fractional Fourier transform.

PubMed

Lang, Jun

2012-01-30

In this paper, we propose a novel secure image sharing scheme based on Shamir's three-pass protocol and the multiple-parameter fractional Fourier transform (MPFRFT), which can safely exchange information with no advance distribution of either secret keys or public keys between users. The image is encrypted directly by the MPFRFT spectrum without the use of phase keys, and information can be shared by transmitting the encrypted image (or message) three times between users. Numerical simulation results are given to verify the performance of the proposed algorithm.

E-mail, decisional styles, and rest breaks.

PubMed

Baker, James R; Phillips, James G

2007-10-01

E-mail is a common but problematic work application. A scale was created to measure tendencies to use e-mail to take breaks (e-breaking); and self-esteem and decisional style (vigilance, procrastination, buck-passing, hypervigilance) were used to predict the self-reported and actual e-mail behaviors of 133 participants (students and marketing employees). Individuals who were low in defensive avoidance (buck-passing) engaged in more e-mailing per week, both in time spent on e-mail and message volume. E-breakers were more likely to engage in behavioral procrastination and spent more time on personal e-mail.

PyPanda: a Python package for gene regulatory network reconstruction

PubMed Central

van IJzendoorn, David G.P.; Glass, Kimberly; Quackenbush, John; Kuijjer, Marieke L.

2016-01-01

Summary: PANDA (Passing Attributes between Networks for Data Assimilation) is a gene regulatory network inference method that uses message-passing to integrate multiple sources of ‘omics data. PANDA was originally coded in C ++. In this application note we describe PyPanda, the Python version of PANDA. PyPanda runs considerably faster than the C ++ version and includes additional features for network analysis. Availability and implementation: The open source PyPanda Python package is freely available at http://github.com/davidvi/pypanda. Contact: mkuijjer@jimmy.harvard.edu or d.g.p.van_ijzendoorn@lumc.nl PMID:27402905

PyPanda: a Python package for gene regulatory network reconstruction.

PubMed

van IJzendoorn, David G P; Glass, Kimberly; Quackenbush, John; Kuijjer, Marieke L

2016-11-01

PANDA (Passing Attributes between Networks for Data Assimilation) is a gene regulatory network inference method that uses message-passing to integrate multiple sources of 'omics data. PANDA was originally coded in C ++. In this application note we describe PyPanda, the Python version of PANDA. PyPanda runs considerably faster than the C ++ version and includes additional features for network analysis. The open source PyPanda Python package is freely available at http://github.com/davidvi/pypanda CONTACT: mkuijjer@jimmy.harvard.edu or d.g.p.van_ijzendoorn@lumc.nl. © The Author 2016. Published by Oxford University Press.

To amend the DNA Analysis Backlog Elimination Act of 2000 to provide for Debbie Smith grants for auditing sexual assault evidence backlogs, and for other purposes.

THOMAS, 112th Congress

Sen. Cornyn, John [R-TX

2012-05-24

Senate - 01/02/2013 Message on House action received in Senate and at desk: House amendments to Senate bill. (All Actions) Tracker: This bill has the status Passed HouseHere are the steps for Status of Legislation:

Support for Debugging Automatically Parallelized Programs

NASA Technical Reports Server (NTRS)

Hood, Robert; Jost, Gabriele

2001-01-01

This viewgraph presentation provides information on support sources available for the automatic parallelization of computer program. CAPTools, a support tool developed at the University of Greenwich, transforms, with user guidance, existing sequential Fortran code into parallel message passing code. Comparison routines are then run for debugging purposes, in essence, ensuring that the code transformation was accurate.

Earth observation taken by the Expedition 43 crew.

NASA Image and Video Library

2015-03-13

Earth observation taken during a day pass by the Expedition 43 crew aboard the International Space Station (ISS). Sent as part of Twitter message: #HappyStPatrickDay with best wishes from the #E43 crew! From space you can see the “Emerald Isle” is very green!

New Frontier Congressional Gold Medal Act

THOMAS, 111th Congress

Sen. Nelson, Bill [D-FL

2009-05-01

Senate - 09/23/2010 Message received in the Senate: Returned to the Senate pursuant to the provisions of H.Res. 1653. (All Actions) Notes: For further action, see H.R.2245, which became Public Law 111-44 on 8/7/2009. Tracker: This bill has the status Passed SenateHere are the steps for Status of Legislation:

Travel Promotion Act of 2009

THOMAS, 111th Congress

Sen. Dorgan, Byron L. [D-ND

2009-05-12

Senate - 09/23/2010 Message received in the Senate: Returned to the Senate pursuant to the provisions of H.Res. 1653. (All Actions) Notes: For further action, see H.R.1299, which became Public Law 111-145 on 3/4/2010. Tracker: This bill has the status Passed SenateHere are the steps for Status of Legislation:

Union Agitators

ERIC Educational Resources Information Center

Honawar, Vaishali

2006-01-01

A decade has passed since a few union leaders formed the network known as Teacher Union Reform Network (TURN) to search for innovative ways to enhance education. Selling their message has not always been easy. Created in 1995, TURN was the brain child of Adam Urbanski, the president of the Rochester (N.Y.) Teachers Association for the past 25…

Monitoring Data-Structure Evolution in Distributed Message-Passing Programs

NASA Technical Reports Server (NTRS)

Sarukkai, Sekhar R.; Beers, Andrew; Woodrow, Thomas S. (Technical Monitor)

1996-01-01

Monitoring the evolution of data structures in parallel and distributed programs, is critical for debugging its semantics and performance. However, the current state-of-art in tracking and presenting data-structure information on parallel and distributed environments is cumbersome and does not scale. In this paper we present a methodology that automatically tracks memory bindings (not the actual contents) of static and dynamic data-structures of message-passing C programs, using PVM. With the help of a number of examples we show that in addition to determining the impact of memory allocation overheads on program performance, graphical views can help in debugging the semantics of program execution. Scalable animations of virtual address bindings of source-level data-structures are used for debugging the semantics of parallel programs across all processors. In conjunction with light-weight core-files, this technique can be used to complement traditional debuggers on single processors. Detailed information (such as data-structure contents), on specific nodes, can be determined using traditional debuggers after the data structure evolution leading to the semantic error is observed graphically.

PVM Wrapper

NASA Technical Reports Server (NTRS)

Katz, Daniel

2004-01-01

PVM Wrapper is a software library that makes it possible for code that utilizes the Parallel Virtual Machine (PVM) software library to run using the message-passing interface (MPI) software library, without needing to rewrite the entire code. PVM and MPI are the two most common software libraries used for applications that involve passing of messages among parallel computers. Since about 1996, MPI has been the de facto standard. Codes written when PVM was popular often feature patterns of {"initsend," "pack," "send"} and {"receive," "unpack"} calls. In many cases, these calls are not contiguous and one set of calls may even exist over multiple subroutines. These characteristics make it difficult to obtain equivalent functionality via a single MPI "send" call. Because PVM Wrapper is written to run with MPI- 1.2, some PVM functions are not permitted and must be replaced - a task that requires some programming expertise. The "pvm_spawn" and "pvm_parent" function calls are not replaced, but a programmer can use "mpirun" and knowledge of the ranks of parent and child tasks with supplied macroinstructions to enable execution of codes that use "pvm_spawn" and "pvm_parent."

Low-pass filtering of noisy Schlumberger sounding curves. Part I: Theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patella, D.

1986-02-01

A contribution is given to the solution of the problem of filtering noise-degraded Schlumberger sounding curves. It is shown that the transformation to the pole-pole system is actually a smoothing operation that filters high-frequency noise. In the case of residual noise contamination in the transformed pole-pole curve, it is demonstrated that a subsequent application of a conventional rectangular low-pass filter, with cut-off frequency not less than the right-hand frequency limit of the main message pass-band, may satisfactorily solve the problem by leaving a pole-pole curve available for interpretation. An attempt is also made to understand the essential peculiarities of themore » pole-pole system as far as penetration depth, resolving power and selectivity power are concerned.« less

Software Mechanisms for Multiprocessor TLB Consistency

DTIC Science & Technology

1989-12-01

thanks. Raj V aswani implemented the DASH message-passing system. Ramesh Govindan implemented part of the DASH virtual memory system. G . Scott...1 Latency (ma) 5𔃺 ---·-r··-·r···r··-T·-·-r··-·r····r····-r··-·r··- . g ~~~R=r 18 -----1·--·-r··-T·----1·--··r·---1·----1·--··r·---T·----1 16...model development. Synchronizing TLBs is similar to updating replicated data in a distributed environment. Lee and Garcia-Molina both used an M/ G /1

Message passing with queues and channels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dozsa, Gabor J; Heidelberger, Philip; Kumar, Sameer

In an embodiment, a reception thread receives a source node identifier, a type, and a data pointer from an application and, in response, creates a receive request. If the source node identifier specifies a source node, the reception thread adds the receive request to a fast-post queue. If a message received from a network does not match a receive request on a posted queue, a polling thread adds a receive request that represents the message to an unexpected queue. If the fast-post queue contains the receive request, the polling thread removes the receive request from the fast-post queue. If themore » receive request that was removed from the fast-post queue does not match the receive request on the unexpected queue, the polling thread adds the receive request that was removed from the fast-post queue to the posted queue. The reception thread and the polling thread execute asynchronously from each other.« less

Secure Web-Site Access with Tickets and Message-Dependent Digests

USGS Publications Warehouse

Donato, David I.

2008-01-01

Although there are various methods for restricting access to documents stored on a World Wide Web (WWW) site (a Web site), none of the widely used methods is completely suitable for restricting access to Web applications hosted on an otherwise publicly accessible Web site. A new technique, however, provides a mix of features well suited for restricting Web-site or Web-application access to authorized users, including the following: secure user authentication, tamper-resistant sessions, simple access to user state variables by server-side applications, and clean session terminations. This technique, called message-dependent digests with tickets, or MDDT, maintains secure user sessions by passing single-use nonces (tickets) and message-dependent digests of user credentials back and forth between client and server. Appendix 2 provides a working implementation of MDDT with PHP server-side code and JavaScript client-side code.

Real time explosive hazard information sensing, processing, and communication for autonomous operation

DOEpatents

Versteeg, Roelof J; Few, Douglas A; Kinoshita, Robert A; Johnson, Doug; Linda, Ondrej

2015-02-24

Methods, computer readable media, and apparatuses provide robotic explosive hazard detection. A robot intelligence kernel (RIK) includes a dynamic autonomy structure with two or more autonomy levels between operator intervention and robot initiative A mine sensor and processing module (ESPM) operating separately from the RIK perceives environmental variables indicative of a mine using subsurface perceptors. The ESPM processes mine information to determine a likelihood of a presence of a mine. A robot can autonomously modify behavior responsive to an indication of a detected mine. The behavior is modified between detection of mines, detailed scanning and characterization of the mine, developing mine indication parameters, and resuming detection. Real time messages are passed between the RIK and the ESPM. A combination of ESPM bound messages and RIK bound messages cause the robot platform to switch between modes including a calibration mode, the mine detection mode, and the mine characterization mode.

Real time explosive hazard information sensing, processing, and communication for autonomous operation

DOEpatents

Versteeg, Roelof J.; Few, Douglas A.; Kinoshita, Robert A.; Johnson, Douglas; Linda, Ondrej

2015-12-15

Methods, computer readable media, and apparatuses provide robotic explosive hazard detection. A robot intelligence kernel (RIK) includes a dynamic autonomy structure with two or more autonomy levels between operator intervention and robot initiative A mine sensor and processing module (ESPM) operating separately from the RIK perceives environmental variables indicative of a mine using subsurface perceptors. The ESPM processes mine information to determine a likelihood of a presence of a mine. A robot can autonomously modify behavior responsive to an indication of a detected mine. The behavior is modified between detection of mines, detailed scanning and characterization of the mine, developing mine indication parameters, and resuming detection. Real time messages are passed between the RIK and the ESPM. A combination of ESPM bound messages and RIK bound messages cause the robot platform to switch between modes including a calibration mode, the mine detection mode, and the mine characterization mode.

Machine-checked proofs of the design and implementation of a fault-tolerant circuit

NASA Technical Reports Server (NTRS)

Bevier, William R.; Young, William D.

1990-01-01

A formally verified implementation of the 'oral messages' algorithm of Pease, Shostak, and Lamport is described. An abstract implementation of the algorithm is verified to achieve interactive consistency in the presence of faults. This abstract characterization is then mapped down to a hardware level implementation which inherits the fault-tolerant characteristics of the abstract version. All steps in the proof were checked with the Boyer-Moore theorem prover. A significant results is the demonstration of a fault-tolerant device that is formally specified and whose implementation is proved correct with respect to this specification. A significant simplifying assumption is that the redundant processors behave synchronously. A mechanically checked proof that the oral messages algorithm is 'optimal' in the sense that no algorithm which achieves agreement via similar message passing can tolerate a larger proportion of faulty processor is also described.

Modeling node bandwidth limits and their effects on vector combining algorithms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Littlefield, R.J.

Each node in a message-passing multicomputer typically has several communication links. However, the maximum aggregate communication speed of a node is often less than the sum of its individual link speeds. Such computers are called node bandwidth limited (NBL). The NBL constraint is important when choosing algorithms because it can change the relative performance of different algorithms that accomplish the same task. This paper introduces a model of communication performance for NBL computers and uses the model to analyze the overall performance of three algorithms for vector combining (global sum) on the Intel Touchstone DELTA computer. Each of the threemore » algorithms is found to be at least 33% faster than the other two for some combinations of machine size and vector length. The NBL constraint is shown to significantly affect the conditions under which each algorithm is fastest.« less

A knowledge base architecture for distributed knowledge agents

NASA Technical Reports Server (NTRS)

Riedesel, Joel; Walls, Bryan

1990-01-01

A tuple space based object oriented model for knowledge base representation and interpretation is presented. An architecture for managing distributed knowledge agents is then implemented within the model. The general model is based upon a database implementation of a tuple space. Objects are then defined as an additional layer upon the database. The tuple space may or may not be distributed depending upon the database implementation. A language for representing knowledge and inference strategy is defined whose implementation takes advantage of the tuple space. The general model may then be instantiated in many different forms, each of which may be a distinct knowledge agent. Knowledge agents may communicate using tuple space mechanisms as in the LINDA model as well as using more well known message passing mechanisms. An implementation of the model is presented describing strategies used to keep inference tractable without giving up expressivity. An example applied to a power management and distribution network for Space Station Freedom is given.

Design and implementation of a hybrid MPI-CUDA model for the Smith-Waterman algorithm.

PubMed

Khaled, Heba; Faheem, Hossam El Deen Mostafa; El Gohary, Rania

2015-01-01

This paper provides a novel hybrid model for solving the multiple pair-wise sequence alignment problem combining message passing interface and CUDA, the parallel computing platform and programming model invented by NVIDIA. The proposed model targets homogeneous cluster nodes equipped with similar Graphical Processing Unit (GPU) cards. The model consists of the Master Node Dispatcher (MND) and the Worker GPU Nodes (WGN). The MND distributes the workload among the cluster working nodes and then aggregates the results. The WGN performs the multiple pair-wise sequence alignments using the Smith-Waterman algorithm. We also propose a modified implementation to the Smith-Waterman algorithm based on computing the alignment matrices row-wise. The experimental results demonstrate a considerable reduction in the running time by increasing the number of the working GPU nodes. The proposed model achieved a performance of about 12 Giga cell updates per second when we tested against the SWISS-PROT protein knowledge base running on four nodes.

Approving the renewal of import restrictions contained in the Burmese Freedom and Democracy Act of 2003.

THOMAS, 112th Congress

Rep. Crowley, Joseph [D-NY-7

2011-05-26

Senate - 09/15/2011 Message on Senate action sent to the House. (All Actions) Notes: For further action, see H.R.2017, which became Public Law 112-33 on 9/30/2011. Tracker: This bill has the status Passed SenateHere are the steps for Status of Legislation:

Final report: Compiled MPI. Cost-Effective Exascale Application Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gropp, William Douglas

2015-12-21

This is the final report on Compiled MPI: Cost-Effective Exascale Application Development, and summarizes the results under this project. The project investigated runtime enviroments that improve the performance of MPI (Message-Passing Interface) programs; work at Illinois in the last period of this project looked at optimizing data access optimizations expressed with MPI datatypes.

Emergency Border Security Supplemental Appropriations Act, 2010

THOMAS, 111th Congress

Rep. Price, David E. [D-NC-4

2010-07-27

Senate - 09/23/2010 Message received in the Senate: Returned to the Senate pursuant to the provisions of H.Res. 1653. (All Actions) Notes: For further action, see H.R.6080, which became Public Law 111-230 on 8/13/2010. Tracker: This bill has the status Passed SenateHere are the steps for Status of Legislation:

A Down-to-Earth Educational Operating System for Up-in-the-Cloud Many-Core Architectures

ERIC Educational Resources Information Center

Ziwisky, Michael; Persohn, Kyle; Brylow, Dennis

2013-01-01

We present "Xipx," the first port of a major educational operating system to a processor in the emerging class of many-core architectures. Through extensions to the proven Embedded Xinu operating system, Xipx gives students hands-on experience with system programming in a distributed message-passing environment. We expose the software primitives…

LDPC Codes--Structural Analysis and Decoding Techniques

ERIC Educational Resources Information Center

Zhang, Xiaojie

2012-01-01

Low-density parity-check (LDPC) codes have been the focus of much research over the past decade thanks to their near Shannon limit performance and to their efficient message-passing (MP) decoding algorithms. However, the error floor phenomenon observed in MP decoding, which manifests itself as an abrupt change in the slope of the error-rate curve,…

Comprehensive Iran Sanctions, Accountability, and Divestment Act of 2009

THOMAS, 111th Congress

Sen. Dodd, Christopher J. [D-CT

2009-11-19

Senate - 09/23/2010 Message received in the Senate: Returned to the Senate pursuant to the provisions of H.Res. 1653. (All Actions) Notes: For further action, see H.R.2194, which became Public Law 111-195 on 7/1/2010. Tracker: This bill has the status Passed SenateHere are the steps for Status of Legislation:

Federal Aviation Administration Extension Act of 2010

THOMAS, 111th Congress

Sen. Rockefeller, John D., IV [D-WV

2010-03-25

Senate - 09/23/2010 Message received in the Senate: Returned to the Senate pursuant to the provisions of H.Res. 1653. (All Actions) Notes: For further action, see H.R.5147, which became Public Law 111-161 on 4/30/2010. Tracker: This bill has the status Passed SenateHere are the steps for Status of Legislation:

Minority Journalists Push Media to Maintain Diversity Commitment

ERIC Educational Resources Information Center

Anderson, Michelle D.

2008-01-01

In a media advisory released earlier this month, the National Association of Black Journalists (NABJ) had an urgent message for the newspaper industry: Diversity should not be treated like a passing fad and it should continue to be a top priority. The advocacy organization, where a majority of its 4,000 members are Black print journalists, warned…

From Our Practices to Yours: Key Messages for the Journey to Integrated Behavioral Health.

PubMed

Gold, Stephanie B; Green, Larry A; Peek, C J

The historic, cultural separation of primary care and behavioral health has caused the spread of integrated care to lag behind other practice transformation efforts. The Advancing Care Together study was a 3-year evaluation of how practices implemented integrated care in their local contexts; at its culmination, practice leaders ("innovators") identified lessons learned to pass on to others. Individual feedback from innovators, key messages created by workgroups of innovators and the study team, and a synthesis of key messages from a facilitated discussion were analyzed for themes via immersion/crystallization. Five key themes were captured: (1) frame integrated care as a necessary paradigm shift to patient-centered, whole-person health care; (2) initialize: define relationships and protocols up-front, understanding they will evolve; (3) build inclusive, empowered teams to provide the foundation for integration; (4) develop a change management strategy of continuous evaluation and course-correction; and (5) use targeted data collection pertinent to integrated care to drive improvement and impart accountability. Innovators integrating primary care and behavioral health discerned key messages from their practical experience that they felt were worth sharing with others. Their messages present insight into the challenges unique to integrating care beyond other practice transformation efforts. © Copyright 2017 by the American Board of Family Medicine.

Concurrent hypercube system with improved message passing

NASA Technical Reports Server (NTRS)

Peterson, John C. (Inventor); Tuazon, Jesus O. (Inventor); Lieberman, Don (Inventor); Pniel, Moshe (Inventor)

1989-01-01

A network of microprocessors, or nodes, are interconnected in an n-dimensional cube having bidirectional communication links along the edges of the n-dimensional cube. Each node's processor network includes an I/O subprocessor dedicated to controlling communication of message packets along a bidirectional communication link with each end thereof terminating at an I/O controlled transceiver. Transmit data lines are directly connected from a local FIFO through each node's communication link transceiver. Status and control signals from the neighboring nodes are delivered over supervisory lines to inform the local node that the neighbor node's FIFO is empty and the bidirectional link between the two nodes is idle for data communication. A clocking line between neighbors, clocks a message into an empty FIFO at a neighbor's node and vica versa. Either neighbor may acquire control over the bidirectional communication link at any time, and thus each node has circuitry for checking whether or not the communication link is busy or idle, and whether or not the receive FIFO is empty. Likewise, each node can empty its own FIFO and in turn deliver a status signal to a neighboring node indicating that the local FIFO is empty. The system includes features of automatic message rerouting, block message transfer and automatic parity checking and generation.

Performance issues for domain-oriented time-driven distributed simulations

NASA Technical Reports Server (NTRS)

Nicol, David M.

1987-01-01

It has long been recognized that simulations form an interesting and important class of computations that may benefit from distributed or parallel processing. Since the point of parallel processing is improved performance, the recent proliferation of multiprocessors requires that we consider the performance issues that naturally arise when attempting to implement a distributed simulation. Three such issues are: (1) the problem of mapping the simulation onto the architecture, (2) the possibilities for performing redundant computation in order to reduce communication, and (3) the avoidance of deadlock due to distributed contention for message-buffer space. These issues are discussed in the context of a battlefield simulation implemented on a medium-scale multiprocessor message-passing architecture.

Parallel integer sorting with medium and fine-scale parallelism

NASA Technical Reports Server (NTRS)

Dagum, Leonardo

1993-01-01

Two new parallel integer sorting algorithms, queue-sort and barrel-sort, are presented and analyzed in detail. These algorithms do not have optimal parallel complexity, yet they show very good performance in practice. Queue-sort designed for fine-scale parallel architectures which allow the queueing of multiple messages to the same destination. Barrel-sort is designed for medium-scale parallel architectures with a high message passing overhead. The performance results from the implementation of queue-sort on a Connection Machine CM-2 and barrel-sort on a 128 processor iPSC/860 are given. The two implementations are found to be comparable in performance but not as good as a fully vectorized bucket sort on the Cray YMP.

Implementing the PM Programming Language using MPI and OpenMP - a New Tool for Programming Geophysical Models on Parallel Systems

NASA Astrophysics Data System (ADS)

Bellerby, Tim

2015-04-01

PM (Parallel Models) is a new parallel programming language specifically designed for writing environmental and geophysical models. The language is intended to enable implementers to concentrate on the science behind the model rather than the details of running on parallel hardware. At the same time PM leaves the programmer in control - all parallelisation is explicit and the parallel structure of any given program may be deduced directly from the code. This paper describes a PM implementation based on the Message Passing Interface (MPI) and Open Multi-Processing (OpenMP) standards, looking at issues involved with translating the PM parallelisation model to MPI/OpenMP protocols and considering performance in terms of the competing factors of finer-grained parallelisation and increased communication overhead. In order to maximise portability, the implementation stays within the MPI 1.3 standard as much as possible, with MPI-2 MPI-IO file handling the only significant exception. Moreover, it does not assume a thread-safe implementation of MPI. PM adopts a two-tier abstract representation of parallel hardware. A PM processor is a conceptual unit capable of efficiently executing a set of language tasks, with a complete parallel system consisting of an abstract N-dimensional array of such processors. PM processors may map to single cores executing tasks using cooperative multi-tasking, to multiple cores or even to separate processing nodes, efficiently sharing tasks using algorithms such as work stealing. While tasks may move between hardware elements within a PM processor, they may not move between processors without specific programmer intervention. Tasks are assigned to processors using a nested parallelism approach, building on ideas from Reyes et al. (2009). The main program owns all available processors. When the program enters a parallel statement then either processors are divided out among the newly generated tasks (number of new tasks < number of processors) or tasks are divided out among the available processors (number of tasks > number of processors). Nested parallel statements may further subdivide the processor set owned by a given task. Tasks or processors are distributed evenly by default, but uneven distributions are possible under programmer control. It is also possible to explicitly enable child tasks to migrate within the processor set owned by their parent task, reducing load unbalancing at the potential cost of increased inter-processor message traffic. PM incorporates some programming structures from the earlier MIST language presented at a previous EGU General Assembly, while adopting a significantly different underlying parallelisation model and type system. PM code is available at www.pm-lang.org under an unrestrictive MIT license. Reference Ruymán Reyes, Antonio J. Dorta, Francisco Almeida, Francisco de Sande, 2009. Automatic Hybrid MPI+OpenMP Code Generation with llc, Recent Advances in Parallel Virtual Machine and Message Passing Interface, Lecture Notes in Computer Science Volume 5759, 185-195

Barista: A Framework for Concurrent Speech Processing by USC-SAIL

PubMed Central

Can, Doğan; Gibson, James; Vaz, Colin; Georgiou, Panayiotis G.; Narayanan, Shrikanth S.

2016-01-01

We present Barista, an open-source framework for concurrent speech processing based on the Kaldi speech recognition toolkit and the libcppa actor library. With Barista, we aim to provide an easy-to-use, extensible framework for constructing highly customizable concurrent (and/or distributed) networks for a variety of speech processing tasks. Each Barista network specifies a flow of data between simple actors, concurrent entities communicating by message passing, modeled after Kaldi tools. Leveraging the fast and reliable concurrency and distribution mechanisms provided by libcppa, Barista lets demanding speech processing tasks, such as real-time speech recognizers and complex training workflows, to be scheduled and executed on parallel (and/or distributed) hardware. Barista is released under the Apache License v2.0. PMID:27610047

Parallel Programming Strategies for Irregular Adaptive Applications

NASA Technical Reports Server (NTRS)

Biswas, Rupak; Biegel, Bryan (Technical Monitor)

2001-01-01

Achieving scalable performance for dynamic irregular applications is eminently challenging. Traditional message-passing approaches have been making steady progress towards this goal; however, they suffer from complex implementation requirements. The use of a global address space greatly simplifies the programming task, but can degrade the performance for such computations. In this work, we examine two typical irregular adaptive applications, Dynamic Remeshing and N-Body, under competing programming methodologies and across various parallel architectures. The Dynamic Remeshing application simulates flow over an airfoil, and refines localized regions of the underlying unstructured mesh. The N-Body experiment models two neighboring Plummer galaxies that are about to undergo a merger. Both problems demonstrate dramatic changes in processor workloads and interprocessor communication with time; thus, dynamic load balancing is a required component.

Barista: A Framework for Concurrent Speech Processing by USC-SAIL.

PubMed

Can, Doğan; Gibson, James; Vaz, Colin; Georgiou, Panayiotis G; Narayanan, Shrikanth S

2014-05-01

We present Barista, an open-source framework for concurrent speech processing based on the Kaldi speech recognition toolkit and the libcppa actor library. With Barista, we aim to provide an easy-to-use, extensible framework for constructing highly customizable concurrent (and/or distributed) networks for a variety of speech processing tasks. Each Barista network specifies a flow of data between simple actors, concurrent entities communicating by message passing, modeled after Kaldi tools. Leveraging the fast and reliable concurrency and distribution mechanisms provided by libcppa, Barista lets demanding speech processing tasks, such as real-time speech recognizers and complex training workflows, to be scheduled and executed on parallel (and/or distributed) hardware. Barista is released under the Apache License v2.0.

Commanding and Controlling Satellite Clusters (IEEE Intelligent Systems, November/December 2000)

DTIC Science & Technology

2000-01-01

real - time operating system , a message-passing OS well suited for distributed...ground Flight processors ObjectAgent RTOS SCL RTOS RDMS Space command language Real - time operating system Rational database management system TS-21 RDMS...engineer with Princeton Satellite Systems. She is working with others to develop ObjectAgent software to run on the OSE Real Time Operating System .

VAC: Versatile Advection Code

NASA Astrophysics Data System (ADS)

Tóth, Gábor; Keppens, Rony

2012-07-01

The Versatile Advection Code (VAC) is a freely available general hydrodynamic and magnetohydrodynamic simulation software that works in 1, 2 or 3 dimensions on Cartesian and logically Cartesian grids. VAC runs on any Unix/Linux system with a Fortran 90 (or 77) compiler and Perl interpreter. VAC can run on parallel machines using either the Message Passing Interface (MPI) library or a High Performance Fortran (HPF) compiler.

Sharing Content and Experiences in Smart Environments

NASA Astrophysics Data System (ADS)

Plomp, Johan; Heinilä, Juhani; Ikonen, Veikko; Kaasinen, Eija; Välkkynen, Pasi

Once upon a time… Stories used to be the only way to pass a message. The story teller would take his audience through the events by mere oration. Here and there he would hesitate, whisper, or gesticulate to emphasise his story or induce the right emotions in his audience. No doubt troubadourswere loved, they both brought news of the world as well as entertainment.

Simulated Raman Spectral Analysis of Organic Molecules

NASA Astrophysics Data System (ADS)

Lu, Lu

The advent of the laser technology in the 1960s solved the main difficulty of Raman spectroscopy, resulted in simplified Raman spectroscopy instruments and also boosted the sensitivity of the technique. Up till now, Raman spectroscopy is commonly used in chemistry and biology. As vibrational information is specific to the chemical bonds, Raman spectroscopy provides fingerprints to identify the type of molecules in the sample. In this thesis, we simulate the Raman Spectrum of organic and inorganic materials by General Atomic and Molecular Electronic Structure System (GAMESS) and Gaussian, two computational codes that perform several general chemistry calculations. We run these codes on our CPU-based high-performance cluster (HPC). Through the message passing interface (MPI), a standardized and portable message-passing system which can make the codes run in parallel, we are able to decrease the amount of time for computation and increase the sizes and capacities of systems simulated by the codes. From our simulations, we will set up a database that allows search algorithm to quickly identify N-H and O-H bonds in different materials. Our ultimate goal is to analyze and identify the spectra of organic matter compositions from meteorites and compared these spectra with terrestrial biologically-produced amino acids and residues.

PyPele Rewritten To Use MPI

NASA Technical Reports Server (NTRS)

Hockney, George; Lee, Seungwon

2008-01-01

A computer program known as PyPele, originally written as a Pythonlanguage extension module of a C++ language program, has been rewritten in pure Python language. The original version of PyPele dispatches and coordinates parallel-processing tasks on cluster computers and provides a conceptual framework for spacecraft-mission- design and -analysis software tools to run in an embarrassingly parallel mode. The original version of PyPele uses SSH (Secure Shell a set of standards and an associated network protocol for establishing a secure channel between a local and a remote computer) to coordinate parallel processing. Instead of SSH, the present Python version of PyPele uses Message Passing Interface (MPI) [an unofficial de-facto standard language-independent application programming interface for message- passing on a parallel computer] while keeping the same user interface. The use of MPI instead of SSH and the preservation of the original PyPele user interface make it possible for parallel application programs written previously for the original version of PyPele to run on MPI-based cluster computers. As a result, engineers using the previously written application programs can take advantage of embarrassing parallelism without need to rewrite those programs.

Detecting and Preventing Sybil Attacks in Wireless Sensor Networks Using Message Authentication and Passing Method.

PubMed

Dhamodharan, Udaya Suriya Raj Kumar; Vayanaperumal, Rajamani

2015-01-01

Wireless sensor networks are highly indispensable for securing network protection. Highly critical attacks of various kinds have been documented in wireless sensor network till now by many researchers. The Sybil attack is a massive destructive attack against the sensor network where numerous genuine identities with forged identities are used for getting an illegal entry into a network. Discerning the Sybil attack, sinkhole, and wormhole attack while multicasting is a tremendous job in wireless sensor network. Basically a Sybil attack means a node which pretends its identity to other nodes. Communication to an illegal node results in data loss and becomes dangerous in the network. The existing method Random Password Comparison has only a scheme which just verifies the node identities by analyzing the neighbors. A survey was done on a Sybil attack with the objective of resolving this problem. The survey has proposed a combined CAM-PVM (compare and match-position verification method) with MAP (message authentication and passing) for detecting, eliminating, and eventually preventing the entry of Sybil nodes in the network. We propose a scheme of assuring security for wireless sensor network, to deal with attacks of these kinds in unicasting and multicasting.

Detecting and Preventing Sybil Attacks in Wireless Sensor Networks Using Message Authentication and Passing Method

PubMed Central

Dhamodharan, Udaya Suriya Raj Kumar; Vayanaperumal, Rajamani

2015-01-01

Wireless sensor networks are highly indispensable for securing network protection. Highly critical attacks of various kinds have been documented in wireless sensor network till now by many researchers. The Sybil attack is a massive destructive attack against the sensor network where numerous genuine identities with forged identities are used for getting an illegal entry into a network. Discerning the Sybil attack, sinkhole, and wormhole attack while multicasting is a tremendous job in wireless sensor network. Basically a Sybil attack means a node which pretends its identity to other nodes. Communication to an illegal node results in data loss and becomes dangerous in the network. The existing method Random Password Comparison has only a scheme which just verifies the node identities by analyzing the neighbors. A survey was done on a Sybil attack with the objective of resolving this problem. The survey has proposed a combined CAM-PVM (compare and match-position verification method) with MAP (message authentication and passing) for detecting, eliminating, and eventually preventing the entry of Sybil nodes in the network. We propose a scheme of assuring security for wireless sensor network, to deal with attacks of these kinds in unicasting and multicasting. PMID:26236773

Streaming data analytics via message passing with application to graph algorithms

DOE PAGES

Plimpton, Steven J.; Shead, Tim

2014-05-06

The need to process streaming data, which arrives continuously at high-volume in real-time, arises in a variety of contexts including data produced by experiments, collections of environmental or network sensors, and running simulations. Streaming data can also be formulated as queries or transactions which operate on a large dynamic data store, e.g. a distributed database. We describe a lightweight, portable framework named PHISH which enables a set of independent processes to compute on a stream of data in a distributed-memory parallel manner. Datums are routed between processes in patterns defined by the application. PHISH can run on top of eithermore » message-passing via MPI or sockets via ZMQ. The former means streaming computations can be run on any parallel machine which supports MPI; the latter allows them to run on a heterogeneous, geographically dispersed network of machines. We illustrate how PHISH can support streaming MapReduce operations, and describe streaming versions of three algorithms for large, sparse graph analytics: triangle enumeration, subgraph isomorphism matching, and connected component finding. Lastly, we also provide benchmark timings for MPI versus socket performance of several kernel operations useful in streaming algorithms.« less

Automated Performance Prediction of Message-Passing Parallel Programs

NASA Technical Reports Server (NTRS)

Block, Robert J.; Sarukkai, Sekhar; Mehra, Pankaj; Woodrow, Thomas S. (Technical Monitor)

1995-01-01

The increasing use of massively parallel supercomputers to solve large-scale scientific problems has generated a need for tools that can predict scalability trends of applications written for these machines. Much work has been done to create simple models that represent important characteristics of parallel programs, such as latency, network contention, and communication volume. But many of these methods still require substantial manual effort to represent an application in the model's format. The NIK toolkit described in this paper is the result of an on-going effort to automate the formation of analytic expressions of program execution time, with a minimum of programmer assistance. In this paper we demonstrate the feasibility of our approach, by extending previous work to detect and model communication patterns automatically, with and without overlapped computations. The predictions derived from these models agree, within reasonable limits, with execution times of programs measured on the Intel iPSC/860 and Paragon. Further, we demonstrate the use of MK in selecting optimal computational grain size and studying various scalability metrics.

User's guide to the Reliability Estimation System Testbed (REST)

NASA Technical Reports Server (NTRS)

Nicol, David M.; Palumbo, Daniel L.; Rifkin, Adam

1992-01-01

The Reliability Estimation System Testbed is an X-window based reliability modeling tool that was created to explore the use of the Reliability Modeling Language (RML). RML was defined to support several reliability analysis techniques including modularization, graphical representation, Failure Mode Effects Simulation (FMES), and parallel processing. These techniques are most useful in modeling large systems. Using modularization, an analyst can create reliability models for individual system components. The modules can be tested separately and then combined to compute the total system reliability. Because a one-to-one relationship can be established between system components and the reliability modules, a graphical user interface may be used to describe the system model. RML was designed to permit message passing between modules. This feature enables reliability modeling based on a run time simulation of the system wide effects of a component's failure modes. The use of failure modes effects simulation enhances the analyst's ability to correctly express system behavior when using the modularization approach to reliability modeling. To alleviate the computation bottleneck often found in large reliability models, REST was designed to take advantage of parallel processing on hypercube processors.

Applications of Multi-Channel Safety Authentication Protocols in Wireless Networks.

PubMed

Chen, Young-Long; Liau, Ren-Hau; Chang, Liang-Yu

2016-01-01

People can use their web browser or mobile devices to access web services and applications which are built into these servers. Users have to input their identity and password to login the server. The identity and password may be appropriated by hackers when the network environment is not safe. The multiple secure authentication protocol can improve the security of the network environment. Mobile devices can be used to pass the authentication messages through Wi-Fi or 3G networks to serve as a second communication channel. The content of the message number is not considered in a multiple secure authentication protocol. The more excessive transmission of messages would be easier to collect and decode by hackers. In this paper, we propose two schemes which allow the server to validate the user and reduce the number of messages using the XOR operation. Our schemes can improve the security of the authentication protocol. The experimental results show that our proposed authentication protocols are more secure and effective. In regard to applications of second authentication communication channels for a smart access control system, identity identification and E-wallet, our proposed authentication protocols can ensure the safety of person and property, and achieve more effective security management mechanisms.

Bad News Has Wings: Dread Risk Mediates Social Amplification in Risk Communication.

PubMed

Jagiello, Robert D; Hills, Thomas T

2018-05-29

Social diffusion of information amplifies risk through processes of birth, death, and distortion of message content. Dread risk-involving uncontrollable, fatal, involuntary, and catastrophic outcomes (e.g., terrorist attacks and nuclear accidents)-may be particularly susceptible to amplification because of the psychological biases inherent in dread risk avoidance. To test this, initially balanced information about high or low dread topics was given to a set of individuals who then communicated this information through diffusion chains, each person passing a message to the next. A subset of these chains were also reexposed to the original information. We measured prior knowledge, perceived risk before and after transmission, and, at each link, number of positive and negative statements. Results showed that the more a message was transmitted the more negative statements it contained. This was highest for the high dread topic. Increased perceived risk and production of negative messages was closely related to the amount of negative information that was received, with domain knowledge mitigating this effect. Reexposue to the initial information was ineffectual in reducing bias, demonstrating the enhanced danger of socially transmitted information. © 2018 Society for Risk Analysis.

Information and the Origin of Qualia

PubMed Central

Orpwood, Roger

2017-01-01

This article argues that qualia are a likely outcome of the processing of information in local cortical networks. It uses an information-based approach and makes a distinction between information structures (the physical embodiment of information in the brain, primarily patterns of action potentials), and information messages (the meaning of those structures to the brain, and the basis of qualia). It develops formal relationships between these two kinds of information, showing how information structures can represent messages, and how information messages can be identified from structures. The article applies this perspective to basic processing in cortical networks or ensembles, showing how networks can transform between the two kinds of information. The article argues that an input pattern of firing is identified by a network as an information message, and that the output pattern of firing generated is a representation of that message. If a network is encouraged to develop an attractor state through attention or other re-entrant processes, then the message identified each time physical information is cycled through the network becomes “representation of the previous message”. Using an example of olfactory perception, it is shown how this piggy-backing of messages on top of previous messages could lead to olfactory qualia. The message identified on each pass of information could evolve from inner identity, to inner form, to inner likeness or image. The outcome is an olfactory quale. It is shown that the same outcome could result from information cycled through a hierarchy of networks in a resonant state. The argument for qualia generation is applied to other sensory modalities, showing how, through a process of brain-wide constraint satisfaction, a particular state of consciousness could develop at any given moment. Evidence for some of the key predictions of the theory is presented, using ECoG data and studies of gamma oscillations and attractors, together with an outline of what further evidence is needed to provide support for the theory. PMID:28484376

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sayan Ghosh, Jeff Hammond

OpenSHMEM is a community effort to unifyt and standardize the SHMEM programming model. MPI (Message Passing Interface) is a well-known community standard for parallel programming using distributed memory. The most recen t release of MPI, version 3.0, was designed in part to support programming models like SHMEM.OSHMPI is an implementation of the OpenSHMEM standard using MPI-3 for the Linux operating system. It is the first implementation of SHMEM over MPI one-sided communication and has the potential to be widely adopted due to the portability and widely availability of Linux and MPI-3. OSHMPI has been tested on a variety of systemsmore » and implementations of MPI-3, includingInfiniBand clusters using MVAPICH2 and SGI shared-memory supercomputers using MPICH. Current support is limited to Linux but may be extended to Apple OSX if there is sufficient interest. The code is opensource via https://github.com/jeffhammond/oshmpi« less

A 3D staggered-grid finite difference scheme for poroelastic wave equation

NASA Astrophysics Data System (ADS)

Zhang, Yijie; Gao, Jinghuai

2014-10-01

Three dimensional numerical modeling has been a viable tool for understanding wave propagation in real media. The poroelastic media can better describe the phenomena of hydrocarbon reservoirs than acoustic and elastic media. However, the numerical modeling in 3D poroelastic media demands significantly more computational capacity, including both computational time and memory. In this paper, we present a 3D poroelastic staggered-grid finite difference (SFD) scheme. During the procedure, parallel computing is implemented to reduce the computational time. Parallelization is based on domain decomposition, and communication between processors is performed using message passing interface (MPI). Parallel analysis shows that the parallelized SFD scheme significantly improves the simulation efficiency and 3D decomposition in domain is the most efficient. We also analyze the numerical dispersion and stability condition of the 3D poroelastic SFD method. Numerical results show that the 3D numerical simulation can provide a real description of wave propagation.

National Combustion Code: Parallel Implementation and Performance

NASA Technical Reports Server (NTRS)

Quealy, A.; Ryder, R.; Norris, A.; Liu, N.-S.

2000-01-01

The National Combustion Code (NCC) is being developed by an industry-government team for the design and analysis of combustion systems. CORSAIR-CCD is the current baseline reacting flow solver for NCC. This is a parallel, unstructured grid code which uses a distributed memory, message passing model for its parallel implementation. The focus of the present effort has been to improve the performance of the NCC flow solver to meet combustor designer requirements for model accuracy and analysis turnaround time. Improving the performance of this code contributes significantly to the overall reduction in time and cost of the combustor design cycle. This paper describes the parallel implementation of the NCC flow solver and summarizes its current parallel performance on an SGI Origin 2000. Earlier parallel performance results on an IBM SP-2 are also included. The performance improvements which have enabled a turnaround of less than 15 hours for a 1.3 million element fully reacting combustion simulation are described.

An Ode to Stuart Hall's "The Supply of Demand": The Case of Post-Secondary Education in Ontario Fifty Years Later

ERIC Educational Resources Information Center

FitzGerald Murphy, Maggie

2016-01-01

Despite the fact that over fifty years have passed since its publication, Stuart Hall's article "The Supply of Demand" (1960), is remarkably relevant today. The central message that society must not be blinded by "prosperity" such that it no longer envisions and demands a better world is especially pertinent in light of the…

The Guardian. Volume 9, Number 3, Winter 2007

DTIC Science & Technology

2007-01-01

message correctly. Muslims will ultimately determine whether the ideology of al Qaeda, its affiliates, franchisees , and fellow travelers represents...opined that the effort would not work or would not pass the cost– benefit comparison. Others wanted to develop comprehensive NATO doctrine to guide...full BAT capability, the access-control benefits of BAT/HIIDE are a significant improvement to overall ISAF force protection, even in stand-alone mode

PETSc Users Manual Revision 3.7

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balay, Satish; Abhyankar, S.; Adams, M.

This manual describes the use of PETSc for the numerical solution of partial differential equations and related problems on high-performance computers. The Portable, Extensible Toolkit for Scientific Computation (PETSc) is a suite of data structures and routines that provide the building blocks for the implementation of large-scale application codes on parallel (and serial) computers. PETSc uses the MPI standard for all message-passing communication.

PETSc Users Manual Revision 3.8

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balay, S.; Abhyankar, S.; Adams, M.

This manual describes the use of PETSc for the numerical solution of partial differential equations and related problems on high-performance computers. The Portable, Extensible Toolkit for Scientific Computation (PETSc) is a suite of data structures and routines that provide the building blocks for the implementation of large-scale application codes on parallel (and serial) computers. PETSc uses the MPI standard for all message-passing communication.

The Solar-Sail Launched Interstellar Probe: Pre-Perihelion Trajectories and Application of Holography

NASA Technical Reports Server (NTRS)

Matloff, Gregory L.

2002-01-01

Design of missions beyond our solar system presents many challenges. Here, we consider certain aspects of the solar-sail launched interstellar probe (ISP), a spacecraft slated for launch in the 2010 time period that is planned to reach the heliopause, at 200 Astronomical Units (AU) from the Sun after a flight of about 20-years duration. The baseline mission under consideration by NASA / JPL has a sail radius of 200 m, a science payload of 25 kg, a spacecraft areal mass thickness of about two grams per square meter and is accelerated out of the solar system at about 14 AU per year after performing a perihelion pass of about 0.25 AU. In current plans, the sail is to be dropped near Jupiter's orbit (5.2 AU from the Sun) on the outbound trajectory leg. One aspect of this study is application of a realistic model of sail thermo-optics to sail kinematics that includes diffuse / specular reflectance and sail roughness. The effects of solar-wind degradation of sail material, based on recent measurements at the NASA MSFC (Marshall Space Flight Center) Space Environment Facility were incorporated in the kinematical model. After setting initial and final conditions for the spacecraft, trajectory was optimized using the provision of variable sail aspect angle. The second phase of the study included consideration of rainbow holography as a medium for a message plaque that would be carried aboard the ISP in the spirit of the message plaques aboard Pioneer 10 /11 and Voyager 1 /2. A prototype holographic message plaque was designed and created by artist C. Bangs with the assistance of Ana Maria Nicholson and Dan Schweitzer of the Center for Holographic Arts in Long Island City, NY. The piece was framed by Simon Liu Inc. of Brooklyn, NY. Concurrent to the creation of the prototype message plaque, we explored the potential of this medium to transmit large amounts of visual information to any extraterrestrial civilization that might detect and intercept ISP. It was also necessary to investigate possible degradation of holograms by the space environment. We developed a new way of characterizing the optical quality of holograms.

Regional-scale calculation of the LS factor using parallel processing

NASA Astrophysics Data System (ADS)

Liu, Kai; Tang, Guoan; Jiang, Ling; Zhu, A.-Xing; Yang, Jianyi; Song, Xiaodong

2015-05-01

With the increase of data resolution and the increasing application of USLE over large areas, the existing serial implementation of algorithms for computing the LS factor is becoming a bottleneck. In this paper, a parallel processing model based on message passing interface (MPI) is presented for the calculation of the LS factor, so that massive datasets at a regional scale can be processed efficiently. The parallel model contains algorithms for calculating flow direction, flow accumulation, drainage network, slope, slope length and the LS factor. According to the existence of data dependence, the algorithms are divided into local algorithms and global algorithms. Parallel strategy are designed according to the algorithm characters including the decomposition method for maintaining the integrity of the results, optimized workflow for reducing the time taken for exporting the unnecessary intermediate data and a buffer-communication-computation strategy for improving the communication efficiency. Experiments on a multi-node system show that the proposed parallel model allows efficient calculation of the LS factor at a regional scale with a massive dataset.

High Performance Geostatistical Modeling of Biospheric Resources

NASA Astrophysics Data System (ADS)

Pedelty, J. A.; Morisette, J. T.; Smith, J. A.; Schnase, J. L.; Crosier, C. S.; Stohlgren, T. J.

2004-12-01

We are using parallel geostatistical codes to study spatial relationships among biospheric resources in several study areas. For example, spatial statistical models based on large- and small-scale variability have been used to predict species richness of both native and exotic plants (hot spots of diversity) and patterns of exotic plant invasion. However, broader use of geostastics in natural resource modeling, especially at regional and national scales, has been limited due to the large computing requirements of these applications. To address this problem, we implemented parallel versions of the kriging spatial interpolation algorithm. The first uses the Message Passing Interface (MPI) in a master/slave paradigm on an open source Linux Beowulf cluster, while the second is implemented with the new proprietary Xgrid distributed processing system on an Xserve G5 cluster from Apple Computer, Inc. These techniques are proving effective and provide the basis for a national decision support capability for invasive species management that is being jointly developed by NASA and the US Geological Survey.

Performance of a parallel code for the Euler equations on hypercube computers

NASA Technical Reports Server (NTRS)

Barszcz, Eric; Chan, Tony F.; Jesperson, Dennis C.; Tuminaro, Raymond S.

1990-01-01

The performance of hypercubes were evaluated on a computational fluid dynamics problem and the parallel environment issues were considered that must be addressed, such as algorithm changes, implementation choices, programming effort, and programming environment. The evaluation focuses on a widely used fluid dynamics code, FLO52, which solves the two dimensional steady Euler equations describing flow around the airfoil. The code development experience is described, including interacting with the operating system, utilizing the message-passing communication system, and code modifications necessary to increase parallel efficiency. Results from two hypercube parallel computers (a 16-node iPSC/2, and a 512-node NCUBE/ten) are discussed and compared. In addition, a mathematical model of the execution time was developed as a function of several machine and algorithm parameters. This model accurately predicts the actual run times obtained and is used to explore the performance of the code in interesting but yet physically realizable regions of the parameter space. Based on this model, predictions about future hypercubes are made.

Parallel implementation of a Lagrangian-based model on an adaptive mesh in C++: Application to sea-ice

NASA Astrophysics Data System (ADS)

Samaké, Abdoulaye; Rampal, Pierre; Bouillon, Sylvain; Ólason, Einar

2017-12-01

We present a parallel implementation framework for a new dynamic/thermodynamic sea-ice model, called neXtSIM, based on the Elasto-Brittle rheology and using an adaptive mesh. The spatial discretisation of the model is done using the finite-element method. The temporal discretisation is semi-implicit and the advection is achieved using either a pure Lagrangian scheme or an Arbitrary Lagrangian Eulerian scheme (ALE). The parallel implementation presented here focuses on the distributed-memory approach using the message-passing library MPI. The efficiency and the scalability of the parallel algorithms are illustrated by the numerical experiments performed using up to 500 processor cores of a cluster computing system. The performance obtained by the proposed parallel implementation of the neXtSIM code is shown being sufficient to perform simulations for state-of-the-art sea ice forecasting and geophysical process studies over geographical domain of several millions squared kilometers like the Arctic region.

Speed and accuracy improvements in FLAASH atmospheric correction of hyperspectral imagery

NASA Astrophysics Data System (ADS)

Perkins, Timothy; Adler-Golden, Steven; Matthew, Michael W.; Berk, Alexander; Bernstein, Lawrence S.; Lee, Jamine; Fox, Marsha

2012-11-01

Remotely sensed spectral imagery of the earth's surface can be used to fullest advantage when the influence of the atmosphere has been removed and the measurements are reduced to units of reflectance. Here, we provide a comprehensive summary of the latest version of the Fast Line-of-sight Atmospheric Analysis of Spectral Hypercubes atmospheric correction algorithm. We also report some new code improvements for speed and accuracy. These include the re-working of the original algorithm in C-language code parallelized with message passing interface and containing a new radiative transfer look-up table option, which replaces executions of the MODTRAN model. With computation times now as low as ~10 s per image per computer processor, automated, real-time, on-board atmospheric correction of hyper- and multi-spectral imagery is within reach.

A practical guide to replica-exchange Wang—Landau simulations

NASA Astrophysics Data System (ADS)

Vogel, Thomas; Li, Ying Wai; Landau, David P.

2018-04-01

This paper is based on a series of tutorial lectures about the replica-exchange Wang-Landau (REWL) method given at the IX Brazilian Meeting on Simulational Physics (BMSP 2017). It provides a practical guide for the implementation of the method. A complete example code for a model system is available online. In this paper, we discuss the main parallel features of this code after a brief introduction to the REWL algorithm. The tutorial section is mainly directed at users who have written a single-walker Wang–Landau program already but might have just taken their first steps in parallel programming using the Message Passing Interface (MPI). In the last section, we answer “frequently asked questions” from users about the implementation of REWL for different scientific problems.

Evaluation Metrics for the Paragon XP/S-15

NASA Technical Reports Server (NTRS)

Traversat, Bernard; McNab, David; Nitzberg, Bill; Fineberg, Sam; Blaylock, Bruce T. (Technical Monitor)

1993-01-01

On February 17th 1993, the Numerical Aerodynamic Simulation (NAS) facility located at the NASA Ames Research Center installed a 224 node Intel Paragon XP/S-15 system. After its installation, the Paragon was found to be in a very immature state and was unable to support a NAS users' workload, composed of a wide range of development and production activities. As a first step towards addressing this problem, we implemented a set of metrics to objectively monitor the system as operating system and hardware upgrades were installed. The metrics were designed to measure four aspects of the system that we consider essential to support our workload: availability, utilization, functionality, and performance. This report presents the metrics collected from February 1993 to August 1993. Since its installation, the Paragon availability has improved from a low of 15% uptime to a high of 80%, while its utilization has remained low. Functionality and performance have improved from merely running one of the NAS Parallel Benchmarks to running all of them faster (between 1 and 2 times) than on the iPSC/860. In spite of the progress accomplished, fundamental limitations of the Paragon operating system are restricting the Paragon from supporting the NAS workload. The maximum operating system message passing (NORMA IPC) bandwidth was measured at 11 Mbytes/s, well below the peak hardware bandwidth (175 Mbytes/s), limiting overall virtual memory and Unix services (i.e. Disk and HiPPI I/O) performance. The high NX application message passing latency (184 microns), three times than on the iPSC/860, was found to significantly degrade performance of applications relying on small message sizes. The amount of memory available for an application was found to be approximately 10 Mbytes per node, indicating that the OS is taking more space than anticipated (6 Mbytes per node).

Tailored motivational message generation: A model and practical framework for real-time physical activity coaching.

PubMed

Op den Akker, Harm; Cabrita, Miriam; Op den Akker, Rieks; Jones, Valerie M; Hermens, Hermie J

2015-06-01

This paper presents a comprehensive and practical framework for automatic generation of real-time tailored messages in behavior change applications. Basic aspects of motivational messages are time, intention, content and presentation. Tailoring of messages to the individual user may involve all aspects of communication. A linear modular system is presented for generating such messages. It is explained how properties of user and context are taken into account in each of the modules of the system and how they affect the linguistic presentation of the generated messages. The model of motivational messages presented is based on an analysis of existing literature as well as the analysis of a corpus of motivational messages used in previous studies. The model extends existing 'ontology-based' approaches to message generation for real-time coaching systems found in the literature. Practical examples are given on how simple tailoring rules can be implemented throughout the various stages of the framework. Such examples can guide further research by clarifying what it means to use e.g. user targeting to tailor a message. As primary example we look at the issue of promoting daily physical activity. Future work is pointed out in applying the present model and framework, defining efficient ways of evaluating individual tailoring components, and improving effectiveness through the creation of accurate and complete user- and context models. Copyright © 2015 Elsevier Inc. All rights reserved.

Saguaro: A Distributed Operating System Based on Pools of Servers.

DTIC Science & Technology

1988-03-25

asynchronous message passing, multicast, and semaphores are supported. We have found this flexibility to be very useful for distributed programming. The...variety of communication primitives provided by SR has facilitated the research of Stella Atkins, who was a visiting professor at Arizona during Spring...data bits in a raw communication channel to help keep the source and destination synchronized , Psync explicitly embeds timing information drawn from the

High-performance computing — an overview

NASA Astrophysics Data System (ADS)

Marksteiner, Peter

1996-08-01

An overview of high-performance computing (HPC) is given. Different types of computer architectures used in HPC are discussed: vector supercomputers, high-performance RISC processors, various parallel computers like symmetric multiprocessors, workstation clusters, massively parallel processors. Software tools and programming techniques used in HPC are reviewed: vectorizing compilers, optimization and vector tuning, optimization for RISC processors; parallel programming techniques like shared-memory parallelism, message passing and data parallelism; and numerical libraries.

Implementation of a Serial Delay Insertion Type Loop Communication for a Real Time Multitransputer System.

DTIC Science & Technology

1985-06-01

just pass the message WAIT NOW AFTER Rlock + timeo t -- if time is out write.screen( TIME IS OUT") MAIN PROGRAM* CHAN linki , link2, link3, link4...PAR D.I.Loop.Interface (link4, linkl,) D.I.Loop.Interface ( linki , link2, 2) D.I.Loop.Interface (link2, link3, 3) JD.I Loop.Interface (link3, link4, 4

Control Transfer in Operating System Kernels

DTIC Science & Technology

1994-05-13

microkernel system that runs less code in the kernel address space. To realize the performance benefit of allocating stacks in unmapped kseg0 memory, the...review how I modified the Mach 3.0 kernel to use continuations. Because of Mach’s message-passing microkernel structure, interprocess communication was...critical control transfer paths, deeply- nested call chains are undesirable in any case because of the function call overhead. 4.1.3 Microkernel Operating

A bill to clarify the health care provided by the Secretary of Veterans Affairs that constitutes minimum essential coverage.

THOMAS, 111th Congress

Sen. Akaka, Daniel K. [D-HI

2010-03-24

Senate - 09/23/2010 Message received in the Senate: Returned to the Senate pursuant to the provisions of H.Res. 1653. (All Actions) Notes: For further action, see H.R.5014, which became Public Law 111-173 on 5/27/2010. Tracker: This bill has the status Passed SenateHere are the steps for Status of Legislation:

Performance Analysis and Optimization of the Winnow Secret Key Reconciliation Protocol

DTIC Science & Technology

2011-06-01

use in a quantum key system can be defined in two ways :  The number of messages passed between Alice and Bob  The...classical and quantum environment. Post- quantum cryptography , which is generally used to describe classical quantum -resilient protocols, includes...composed of a one- way quantum channel and a two - way classical channel. Owing to the physics of the channel, the quantum channel is subject to

FPGA implementation of low complexity LDPC iterative decoder

NASA Astrophysics Data System (ADS)

Verma, Shivani; Sharma, Sanjay

2016-07-01

Low-density parity-check (LDPC) codes, proposed by Gallager, emerged as a class of codes which can yield very good performance on the additive white Gaussian noise channel as well as on the binary symmetric channel. LDPC codes have gained lots of importance due to their capacity achieving property and excellent performance in the noisy channel. Belief propagation (BP) algorithm and its approximations, most notably min-sum, are popular iterative decoding algorithms used for LDPC and turbo codes. The trade-off between the hardware complexity and the decoding throughput is a critical factor in the implementation of the practical decoder. This article presents introduction to LDPC codes and its various decoding algorithms followed by realisation of LDPC decoder by using simplified message passing algorithm and partially parallel decoder architecture. Simplified message passing algorithm has been proposed for trade-off between low decoding complexity and decoder performance. It greatly reduces the routing and check node complexity of the decoder. Partially parallel decoder architecture possesses high speed and reduced complexity. The improved design of the decoder possesses a maximum symbol throughput of 92.95 Mbps and a maximum of 18 decoding iterations. The article presents implementation of 9216 bits, rate-1/2, (3, 6) LDPC decoder on Xilinx XC3D3400A device from Spartan-3A DSP family.

"Some convincing arguments to pass back to nervous customers": the role of the tobacco retailer in the Australian tobacco industry's smoker reassurance campaign 1950-1978.

PubMed

Tofler, A; Chapman, S

2003-12-01

Epidemiological studies and reports on smoking and health published in the 1950s and 1960s threatened the tobacco industry worldwide, which acted to reassure smokers and counteract mounting evidence that smoking posed a serious risk to smokers' health. To document the use of tobacco retailers (1) as a conduit to pass messages of reassurance onto smokers, and (2) to recruit youth and women into smoking. Review of an extensive collection of Australian tobacco retail trade journals (1950-1978) for articles consistent with the industry's efforts to counter messages about smoking and health, and how to attract non-smokers, particularly youth and women. The main arguments advanced in the journals included the notion that air pollution and other substances cause cancer, that "statistics" did not constitute proof in the tobacco health scare, and that the industry was committed to research into the causes of cancer and into developing a "safer" cigarette. Numerous articles designed to be reiterated to customers were published, arguing against the link between tobacco and ill health. Tobacco retailers, salesmen and retail trade organisations played a significant role in dissembling the tobacco health nexus. Tobacco retail journals may be an important component in tobacco industry misinformation strategies.

A practical approach to portability and performance problems on massively parallel supercomputers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beazley, D.M.; Lomdahl, P.S.

1994-12-08

We present an overview of the tactics we have used to achieve a high-level of performance while improving portability for a large-scale molecular dynamics code SPaSM. SPaSM was originally implemented in ANSI C with message passing for the Connection Machine 5 (CM-5). In 1993, SPaSM was selected as one of the winners in the IEEE Gordon Bell Prize competition for sustaining 50 Gflops on the 1024 node CM-5 at Los Alamos National Laboratory. Achieving this performance on the CM-5 required rewriting critical sections of code in CDPEAC assembler language. In addition, the code made extensive use of CM-5 parallel I/Omore » and the CMMD message passing library. Given this highly specialized implementation, we describe how we have ported the code to the Cray T3D and high performance workstations. In addition we will describe how it has been possible to do this using a single version of source code that runs on all three platforms without sacrificing any performance. Sound too good to be true? We hope to demonstrate that one can realize both code performance and portability without relying on the latest and greatest prepackaged tool or parallelizing compiler.« less

Toward Abstracting the Communication Intent in Applications to Improve Portability and Productivity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mintz, Tiffany M; Hernandez, Oscar R; Kartsaklis, Christos

Programming with communication libraries such as the Message Passing Interface (MPI) obscures the high-level intent of the communication in an application and makes static communication analysis difficult to do. Compilers are unaware of communication libraries specifics, leading to the exclusion of communication patterns from any automated analysis and optimizations. To overcome this, communication patterns can be expressed at higher-levels of abstraction and incrementally added to existing MPI applications. In this paper, we propose the use of directives to clearly express the communication intent of an application in a way that is not specific to a given communication library. Our communicationmore » directives allow programmers to express communication among processes in a portable way, giving hints to the compiler on regions of computations that can be overlapped with communication and relaxing communication constraints on the ordering, completion and synchronization of the communication imposed by specific libraries such as MPI. The directives can then be translated by the compiler into message passing calls that efficiently implement the intended pattern and be targeted to multiple communication libraries. Thus far, we have used the directives to express point-to-point communication patterns in C, C++ and Fortran applications, and have translated them to MPI and SHMEM.« less

A new control system hardware architecture for the Hobby-Eberly Telescope prime focus instrument package

NASA Astrophysics Data System (ADS)

Ramiller, Chuck; Taylor, Trey; Rafferty, Tom H.; Cornell, Mark E.; Rafal, Marc; Savage, Richard

2010-07-01

The Hobby-Eberly Telescope (HET) will be undergoing a major upgrade as a precursor to the HET Dark Energy Experiment (HETDEX‡). As part of this upgrade, the Prime Focus Instrument Package (PFIP) will be replaced with a new design that supports the HETDEX requirements along with the existing suite of instruments and anticipated future additions. This paper describes the new PFIP control system hardware plus the physical constraints and other considerations driving its design. Because of its location at the top end of the telescope, the new PFIP is essentially a stand-alone remote automation island containing over a dozen subsystems. Within the PFIP, motion controllers and modular IO systems are interconnected using a local Controller Area Network (CAN) bus and the CANOpen messaging protocol. CCD cameras that are equipped only with USB 2.0 interfaces are connected to a local Ethernet network via small microcontroller boards running embedded Linux. Links to ground-level systems pass through a 100 m cable bundle and use Ethernet over fiber optic cable exclusively; communications are either direct or through Ethernet/CAN gateways that pass CANOpen messages transparently. All of the control system hardware components are commercially available, designed for rugged industrial applications, and rated for extended temperature operation down to -10 °C.

Compiling global name-space programs for distributed execution

NASA Technical Reports Server (NTRS)

Koelbel, Charles; Mehrotra, Piyush

1990-01-01

Distributed memory machines do not provide hardware support for a global address space. Thus programmers are forced to partition the data across the memories of the architecture and use explicit message passing to communicate data between processors. The compiler support required to allow programmers to express their algorithms using a global name-space is examined. A general method is presented for analysis of a high level source program and along with its translation to a set of independently executing tasks communicating via messages. If the compiler has enough information, this translation can be carried out at compile-time. Otherwise run-time code is generated to implement the required data movement. The analysis required in both situations is described and the performance of the generated code on the Intel iPSC/2 is presented.

The Raid distributed database system

NASA Technical Reports Server (NTRS)

Bhargava, Bharat; Riedl, John

1989-01-01

Raid, a robust and adaptable distributed database system for transaction processing (TP), is described. Raid is a message-passing system, with server processes on each site to manage concurrent processing, consistent replicated copies during site failures, and atomic distributed commitment. A high-level layered communications package provides a clean location-independent interface between servers. The latest design of the package delivers messages via shared memory in a configuration with several servers linked into a single process. Raid provides the infrastructure to investigate various methods for supporting reliable distributed TP. Measurements on TP and server CPU time are presented, along with data from experiments on communications software, consistent replicated copy control during site failures, and concurrent distributed checkpointing. A software tool for evaluating the implementation of TP algorithms in an operating-system kernel is proposed.

Plasma Physics Calculations on a Parallel Macintosh Cluster

NASA Astrophysics Data System (ADS)

Decyk, Viktor; Dauger, Dean; Kokelaar, Pieter

2000-03-01

We have constructed a parallel cluster consisting of 16 Apple Macintosh G3 computers running the MacOS, and achieved very good performance on numerically intensive, parallel plasma particle-in-cell simulations. A subset of the MPI message-passing library was implemented in Fortran77 and C. This library enabled us to port code, without modification, from other parallel processors to the Macintosh cluster. For large problems where message packets are large and relatively few in number, performance of 50-150 MFlops/node is possible, depending on the problem. This is fast enough that 3D calculations can be routinely done. Unlike Unix-based clusters, no special expertise in operating systems is required to build and run the cluster. Full details are available on our web site: http://exodus.physics.ucla.edu/appleseed/.

Plasma Physics Calculations on a Parallel Macintosh Cluster

NASA Astrophysics Data System (ADS)

Decyk, Viktor K.; Dauger, Dean E.; Kokelaar, Pieter R.

We have constructed a parallel cluster consisting of 16 Apple Macintosh G3 computers running the MacOS, and achieved very good performance on numerically intensive, parallel plasma particle-in-cell simulations. A subset of the MPI message-passing library was implemented in Fortran77 and C. This library enabled us to port code, without modification, from other parallel processors to the Macintosh cluster. For large problems where message packets are large and relatively few in number, performance of 50-150 Mflops/node is possible, depending on the problem. This is fast enough that 3D calculations can be routinely done. Unlike Unix-based clusters, no special expertise in operating systems is required to build and run the cluster. Full details are available on our web site: http://exodus.physics.ucla.edu/appleseed/.

A two-stage broadcast message propagation model in social networks

NASA Astrophysics Data System (ADS)

Wang, Dan; Cheng, Shun-Jun

2016-11-01

Message propagation in social networks is becoming a popular topic in complex networks. One of the message types in social networks is called broadcast message. It refers to a type of message which has a unique and unknown destination for the publisher, such as 'lost and found'. Its propagation always has two stages. Due to this feature, rumor propagation model and epidemic propagation model have difficulty in describing this message's propagation accurately. In this paper, an improved two-stage susceptible-infected-removed model is proposed. We come up with the concept of the first forwarding probability and the second forwarding probability. Another part of our work is figuring out the influence to the successful message transmission chance in each level resulting from multiple reasons, including the topology of the network, the receiving probability, the first stage forwarding probability, the second stage forwarding probability as well as the length of the shortest path between the publisher and the relevant destination. The proposed model has been simulated on real networks and the results proved the model's effectiveness.

Supporting Beacon and Event-Driven Messages in Vehicular Platoons through Token-Based Strategies

PubMed Central

Uhlemann, Elisabeth

2018-01-01

Timely and reliable inter-vehicle communications is a critical requirement to support traffic safety applications, such as vehicle platooning. Furthermore, low-delay communications allow the platoon to react quickly to unexpected events. In this scope, having a predictable and highly effective medium access control (MAC) method is of utmost importance. However, the currently available IEEE 802.11p technology is unable to adequately address these challenges. In this paper, we propose a MAC method especially adapted to platoons, able to transmit beacons within the required time constraints, but with a higher reliability level than IEEE 802.11p, while concurrently enabling efficient dissemination of event-driven messages. The protocol circulates the token within the platoon not in a round-robin fashion, but based on beacon data age, i.e., the time that has passed since the previous collection of status information, thereby automatically offering repeated beacon transmission opportunities for increased reliability. In addition, we propose three different methods for supporting event-driven messages co-existing with beacons. Analysis and simulation results in single and multi-hop scenarios showed that, by providing non-competitive channel access and frequent retransmission opportunities, our protocol can offer beacon delivery within one beacon generation interval while fulfilling the requirements on low-delay dissemination of event-driven messages for traffic safety applications. PMID:29570676

Supporting Beacon and Event-Driven Messages in Vehicular Platoons through Token-Based Strategies.

PubMed

Balador, Ali; Uhlemann, Elisabeth; Calafate, Carlos T; Cano, Juan-Carlos

2018-03-23

Timely and reliable inter-vehicle communications is a critical requirement to support traffic safety applications, such as vehicle platooning. Furthermore, low-delay communications allow the platoon to react quickly to unexpected events. In this scope, having a predictable and highly effective medium access control (MAC) method is of utmost importance. However, the currently available IEEE 802.11p technology is unable to adequately address these challenges. In this paper, we propose a MAC method especially adapted to platoons, able to transmit beacons within the required time constraints, but with a higher reliability level than IEEE 802.11p, while concurrently enabling efficient dissemination of event-driven messages. The protocol circulates the token within the platoon not in a round-robin fashion, but based on beacon data age, i.e., the time that has passed since the previous collection of status information, thereby automatically offering repeated beacon transmission opportunities for increased reliability. In addition, we propose three different methods for supporting event-driven messages co-existing with beacons. Analysis and simulation results in single and multi-hop scenarios showed that, by providing non-competitive channel access and frequent retransmission opportunities, our protocol can offer beacon delivery within one beacon generation interval while fulfilling the requirements on low-delay dissemination of event-driven messages for traffic safety applications.

Assessing clarity of message communication for mandated USEPA drinking water quality reports.

PubMed

Phetxumphou, Katherine; Roy, Siddhartha; Davy, Brenda M; Estabrooks, Paul A; You, Wen; Dietrich, Andrea M

2016-04-01

The United States Environmental Protection Agency mandates that community water systems (CWSs), or drinking water utilities, provide annual consumer confidence reports (CCRs) reporting on water quality, compliance with regulations, source water, and consumer education. While certain report formats are prescribed, there are no criteria ensuring that consumers understand messages in these reports. To assess clarity of message, trained raters evaluated a national sample of 30 CCRs using the Centers for Disease Control Clear Communication Index (Index) indices: (1) Main Message/Call to Action; (2) Language; (3) Information Design; (4) State of the Science; (5) Behavioral Recommendations; (6) Numbers; and (7) Risk. Communication materials are considered qualifying if they achieve a 90% Index score. Overall mean score across CCRs was 50 ± 14% and none scored 90% or higher. CCRs did not differ significantly by water system size. State of the Science (3 ± 15%) and Behavioral Recommendations (77 ± 36%) indices were the lowest and highest, respectively. Only 63% of CCRs explicitly stated if the water was safe to drink according to federal and state standards and regulations. None of the CCRs had passing Index scores, signaling that CWSs are not effectively communicating with their consumers; thus, the Index can serve as an evaluation tool for CCR effectiveness and a guide to improve water quality communications.

The Physical Therapy and Society Summit (PASS) Meeting: observations and opportunities.

PubMed

Kigin, Colleen M; Rodgers, Mary M; Wolf, Steven L

2010-11-01

The construct of delivering high-quality and cost-effective health care is in flux, and the profession must strategically plan how to meet the needs of society. In 2006, the House of Delegates of the American Physical Therapy Association passed a motion to convene a summit on "how physical therapists can meet current, evolving, and future societal health care needs." The Physical Therapy and Society Summit (PASS) meeting on February 27-28, 2009, in Leesburg, Virginia, sent a clear message that for physical therapists to be effective and thrive in the health care environment of the future, a paradigm shift is required. During the PASS meeting, participants reframed our traditional focus on the physical therapist and the patient/client (consumer) to one in which physical therapists are an integral part of a collaborative, multidisciplinary health care team with the health care consumer as its focus. The PASS Steering Committee recognized that some of the opportunities that surfaced during the PASS meeting may be disruptive or may not be within the profession's present strategic or tactical plans. Thus, adopting a framework that helps to establish the need for change that is provocative and potentially disruptive to our present care delivery, yet prioritizes opportunities, is a critical and essential step. Each of us in the physical therapy profession must take on post-PASS roles and responsibilities to accomplish the systemic change that is so intimately intertwined with our destiny. This article offers a perspective of the dynamic dialogue and suggestions that emerged from the PASS event, providing further opportunities for discussion and action within our profession.

Monitoring and Modeling Performance of Communications in Computational Grids

NASA Technical Reports Server (NTRS)

Frumkin, Michael A.; Le, Thuy T.

2003-01-01

Computational grids may include many machines located in a number of sites. For efficient use of the grid we need to have an ability to estimate the time it takes to communicate data between the machines. For dynamic distributed grids it is unrealistic to know exact parameters of the communication hardware and the current communication traffic and we should rely on a model of the network performance to estimate the message delivery time. Our approach to a construction of such a model is based on observation of the messages delivery time with various message sizes and time scales. We record these observations in a database and use them to build a model of the message delivery time. Our experiments show presence of multiple bands in the logarithm of the message delivery times. These multiple bands represent multiple paths messages travel between the grid machines and are incorporated in our multiband model.

Parallel distributed, reciprocal Monte Carlo radiation in coupled, large eddy combustion simulations

NASA Astrophysics Data System (ADS)

Hunsaker, Isaac L.

Radiation is the dominant mode of heat transfer in high temperature combustion environments. Radiative heat transfer affects the gas and particle phases, including all the associated combustion chemistry. The radiative properties are in turn affected by the turbulent flow field. This bi-directional coupling of radiation turbulence interactions poses a major challenge in creating parallel-capable, high-fidelity combustion simulations. In this work, a new model was developed in which reciprocal monte carlo radiation was coupled with a turbulent, large-eddy simulation combustion model. A technique wherein domain patches are stitched together was implemented to allow for scalable parallelism. The combustion model runs in parallel on a decomposed domain. The radiation model runs in parallel on a recomposed domain. The recomposed domain is stored on each processor after information sharing of the decomposed domain is handled via the message passing interface. Verification and validation testing of the new radiation model were favorable. Strong scaling analyses were performed on the Ember cluster and the Titan cluster for the CPU-radiation model and GPU-radiation model, respectively. The model demonstrated strong scaling to over 1,700 and 16,000 processing cores on Ember and Titan, respectively.

A hybrid parallel framework for the cellular Potts model simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Yi; He, Kejing; Dong, Shoubin

2009-01-01

The Cellular Potts Model (CPM) has been widely used for biological simulations. However, most current implementations are either sequential or approximated, which can't be used for large scale complex 3D simulation. In this paper we present a hybrid parallel framework for CPM simulations. The time-consuming POE solving, cell division, and cell reaction operation are distributed to clusters using the Message Passing Interface (MPI). The Monte Carlo lattice update is parallelized on shared-memory SMP system using OpenMP. Because the Monte Carlo lattice update is much faster than the POE solving and SMP systems are more and more common, this hybrid approachmore » achieves good performance and high accuracy at the same time. Based on the parallel Cellular Potts Model, we studied the avascular tumor growth using a multiscale model. The application and performance analysis show that the hybrid parallel framework is quite efficient. The hybrid parallel CPM can be used for the large scale simulation ({approx}10{sup 8} sites) of complex collective behavior of numerous cells ({approx}10{sup 6}).« less

Power flow prediction in vibrating systems via model reduction

NASA Astrophysics Data System (ADS)

Li, Xianhui

This dissertation focuses on power flow prediction in vibrating systems. Reduced order models (ROMs) are built based on rational Krylov model reduction which preserve power flow information in the original systems over a specified frequency band. Stiffness and mass matrices of the ROMs are obtained by projecting the original system matrices onto the subspaces spanned by forced responses. A matrix-free algorithm is designed to construct ROMs directly from the power quantities at selected interpolation frequencies. Strategies for parallel implementation of the algorithm via message passing interface are proposed. The quality of ROMs is iteratively refined according to the error estimate based on residual norms. Band capacity is proposed to provide a priori estimate of the sizes of good quality ROMs. Frequency averaging is recast as ensemble averaging and Cauchy distribution is used to simplify the computation. Besides model reduction for deterministic systems, details of constructing ROMs for parametric and nonparametric random systems are also presented. Case studies have been conducted on testbeds from Harwell-Boeing collections. Input and coupling power flow are computed for the original systems and the ROMs. Good agreement is observed in all cases.

Parallel deterministic neutronics with AMR in 3D

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clouse, C.; Ferguson, J.; Hendrickson, C.

1997-12-31

AMTRAN, a three dimensional Sn neutronics code with adaptive mesh refinement (AMR) has been parallelized over spatial domains and energy groups and runs on the Meiko CS-2 with MPI message passing. Block refined AMR is used with linear finite element representations for the fluxes, which allows for a straight forward interpretation of fluxes at block interfaces with zoning differences. The load balancing algorithm assumes 8 spatial domains, which minimizes idle time among processors.

GENASIS Basics: Object-oriented utilitarian functionality for large-scale physics simulations (Version 2)

NASA Astrophysics Data System (ADS)

Cardall, Christian Y.; Budiardja, Reuben D.

2017-05-01

GenASiS Basics provides Fortran 2003 classes furnishing extensible object-oriented utilitarian functionality for large-scale physics simulations on distributed memory supercomputers. This functionality includes physical units and constants; display to the screen or standard output device; message passing; I/O to disk; and runtime parameter management and usage statistics. This revision -Version 2 of Basics - makes mostly minor additions to functionality and includes some simplifying name changes.

A Survey of Rollback-Recovery Protocols in Message-Passing Systems

DTIC Science & Technology

1999-06-01

and M.A. Castillo. "Checkpointing through garbage collection." Technical report. Departamento de Ciencia de la Computation, Escuela de Ingenieria ...between consecutive checkpoints. It can be implemented by using the dirty-bit of the memory protection hardware or by emulating a dirty-bit in software [4...compare the program’s state with the previous checkpoint in software , and writing the difference in a new checkpoint [46]. The required storage and

An HLA-Based Approach to Quantify Achievable Performance for Tactical Edge Applications

DTIC Science & Technology

2011-05-01

in: Proceedings of the 2002 Fall Simulation Interoperability Workshop, 02F- SIW -068, Nov 2002. [16] P. Knight, et al. ―WBT RTI Independent...Benchmark Tests: Design, Implementation, and Updated Results‖, in: Proceedings of the 2002 Spring Simulation Interoperability Workshop, 02S- SIW -081, March...Interoperability Workshop, 98F- SIW -085, Nov 1998. [18] S. Ferenci and R. Fujimoto. ―RTI Performance on Shared Memory and Message Passing Architectures‖, in

Compiled MPI: Cost-Effective Exascale Applications Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bronevetsky, G; Quinlan, D; Lumsdaine, A

2012-04-10

The complexity of petascale and exascale machines makes it increasingly difficult to develop applications that can take advantage of them. Future systems are expected to feature billion-way parallelism, complex heterogeneous compute nodes and poor availability of memory (Peter Kogge, 2008). This new challenge for application development is motivating a significant amount of research and development on new programming models and runtime systems designed to simplify large-scale application development. Unfortunately, DoE has significant multi-decadal investment in a large family of mission-critical scientific applications. Scaling these applications to exascale machines will require a significant investment that will dwarf the costs of hardwaremore » procurement. A key reason for the difficulty in transitioning today's applications to exascale hardware is their reliance on explicit programming techniques, such as the Message Passing Interface (MPI) programming model to enable parallelism. MPI provides a portable and high performance message-passing system that enables scalable performance on a wide variety of platforms. However, it also forces developers to lock the details of parallelization together with application logic, making it very difficult to adapt the application to significant changes in the underlying system. Further, MPI's explicit interface makes it difficult to separate the application's synchronization and communication structure, reducing the amount of support that can be provided by compiler and run-time tools. This is in contrast to the recent research on more implicit parallel programming models such as Chapel, OpenMP and OpenCL, which promise to provide significantly more flexibility at the cost of reimplementing significant portions of the application. We are developing CoMPI, a novel compiler-driven approach to enable existing MPI applications to scale to exascale systems with minimal modifications that can be made incrementally over the application's lifetime. It includes: (1) New set of source code annotations, inserted either manually or automatically, that will clarify the application's use of MPI to the compiler infrastructure, enabling greater accuracy where needed; (2) A compiler transformation framework that leverages these annotations to transform the original MPI source code to improve its performance and scalability; (3) Novel MPI runtime implementation techniques that will provide a rich set of functionality extensions to be used by applications that have been transformed by our compiler; and (4) A novel compiler analysis that leverages simple user annotations to automatically extract the application's communication structure and synthesize most complex code annotations.« less

3-Dimensional Marine CSEM Modeling by Employing TDFEM with Parallel Solvers

NASA Astrophysics Data System (ADS)

Wu, X.; Yang, T.

2013-12-01

In this paper, parallel fulfillment is developed for forward modeling of the 3-Dimensional controlled source electromagnetic (CSEM) by using time-domain finite element method (TDFEM). Recently, a greater attention rises on research of hydrocarbon (HC) reservoir detection mechanism in the seabed. Since China has vast ocean resources, seeking hydrocarbon reservoirs become significant in the national economy. However, traditional methods of seismic exploration shown a crucial obstacle to detect hydrocarbon reservoirs in the seabed with a complex structure, due to relatively high acquisition costs and high-risking exploration. In addition, the development of EM simulations typically requires both a deep knowledge of the computational electromagnetics (CEM) and a proper use of sophisticated techniques and tools from computer science. However, the complexity of large-scale EM simulations often requires large memory because of a large amount of data, or solution time to address problems concerning matrix solvers, function transforms, optimization, etc. The objective of this paper is to present parallelized implementation of the time-domain finite element method for analysis of three-dimensional (3D) marine controlled source electromagnetic problems. Firstly, we established a three-dimensional basic background model according to the seismic data, then electromagnetic simulation of marine CSEM was carried out by using time-domain finite element method, which works on a MPI (Message Passing Interface) platform with exact orientation to allow fast detecting of hydrocarbons targets in ocean environment. To speed up the calculation process, SuperLU of an MPI (Message Passing Interface) version called SuperLU_DIST is employed in this approach. Regarding the representation of three-dimension seabed terrain with sense of reality, the region is discretized into an unstructured mesh rather than a uniform one in order to reduce the number of unknowns. Moreover, high-order Whitney vector basis functions are used for spatial discretization within the finite element approach to approximate the electric field. A horizontal electric dipole was used as a source, and an array of the receiver located at the seabed. To capture the presence of the hydrocarbon layer, the forward responses at water depths from 100m to 3000m are calculated. The normalized Magnitude Versus Offset (N-MVO) and Phase Versus Offset (PVO) curve can reflect resistive characteristics of hydrocarbon layers. For future work, Graphics Process Unit (GPU) acceleration algorithm would be carried out to multiply the calculation efficiency greatly.

Coding for Parallel Links to Maximize the Expected Value of Decodable Messages

NASA Technical Reports Server (NTRS)

Klimesh, Matthew A.; Chang, Christopher S.

2011-01-01

When multiple parallel communication links are available, it is useful to consider link-utilization strategies that provide tradeoffs between reliability and throughput. Interesting cases arise when there are three or more available links. Under the model considered, the links have known probabilities of being in working order, and each link has a known capacity. The sender has a number of messages to send to the receiver. Each message has a size and a value (i.e., a worth or priority). Messages may be divided into pieces arbitrarily, and the value of each piece is proportional to its size. The goal is to choose combinations of messages to send on the links so that the expected value of the messages decodable by the receiver is maximized. There are three parts to the innovation: (1) Applying coding to parallel links under the model; (2) Linear programming formulation for finding the optimal combinations of messages to send on the links; and (3) Algorithms for assisting in finding feasible combinations of messages, as support for the linear programming formulation. There are similarities between this innovation and methods developed in the field of network coding. However, network coding has generally been concerned with either maximizing throughput in a fixed network, or robust communication of a fixed volume of data. In contrast, under this model, the throughput is expected to vary depending on the state of the network. Examples of error-correcting codes that are useful under this model but which are not needed under previous models have been found. This model can represent either a one-shot communication attempt, or a stream of communications. Under the one-shot model, message sizes and link capacities are quantities of information (e.g., measured in bits), while under the communications stream model, message sizes and link capacities are information rates (e.g., measured in bits/second). This work has the potential to increase the value of data returned from spacecraft under certain conditions.

Development of a Grid-Independent Geos-Chem Chemical Transport Model (v9-02) as an Atmospheric Chemistry Module for Earth System Models

NASA Technical Reports Server (NTRS)

Long, M. S.; Yantosca, R.; Nielsen, J. E; Keller, C. A.; Da Silva, A.; Sulprizio, M. P.; Pawson, S.; Jacob, D. J.

2015-01-01

The GEOS-Chem global chemical transport model (CTM), used by a large atmospheric chemistry research community, has been re-engineered to also serve as an atmospheric chemistry module for Earth system models (ESMs). This was done using an Earth System Modeling Framework (ESMF) interface that operates independently of the GEOSChem scientific code, permitting the exact same GEOSChem code to be used as an ESM module or as a standalone CTM. In this manner, the continual stream of updates contributed by the CTM user community is automatically passed on to the ESM module, which remains state of science and referenced to the latest version of the standard GEOS-Chem CTM. A major step in this re-engineering was to make GEOS-Chem grid independent, i.e., capable of using any geophysical grid specified at run time. GEOS-Chem data sockets were also created for communication between modules and with external ESM code. The grid-independent, ESMF-compatible GEOS-Chem is now the standard version of the GEOS-Chem CTM. It has been implemented as an atmospheric chemistry module into the NASA GEOS- 5 ESM. The coupled GEOS-5-GEOS-Chem system was tested for scalability and performance with a tropospheric oxidant-aerosol simulation (120 coupled species, 66 transported tracers) using 48-240 cores and message-passing interface (MPI) distributed-memory parallelization. Numerical experiments demonstrate that the GEOS-Chem chemistry module scales efficiently for the number of cores tested, with no degradation as the number of cores increases. Although inclusion of atmospheric chemistry in ESMs is computationally expensive, the excellent scalability of the chemistry module means that the relative cost goes down with increasing number of cores in a massively parallel environment.

SKIRT: Hybrid parallelization of radiative transfer simulations

NASA Astrophysics Data System (ADS)

Verstocken, S.; Van De Putte, D.; Camps, P.; Baes, M.

2017-07-01

We describe the design, implementation and performance of the new hybrid parallelization scheme in our Monte Carlo radiative transfer code SKIRT, which has been used extensively for modelling the continuum radiation of dusty astrophysical systems including late-type galaxies and dusty tori. The hybrid scheme combines distributed memory parallelization, using the standard Message Passing Interface (MPI) to communicate between processes, and shared memory parallelization, providing multiple execution threads within each process to avoid duplication of data structures. The synchronization between multiple threads is accomplished through atomic operations without high-level locking (also called lock-free programming). This improves the scaling behaviour of the code and substantially simplifies the implementation of the hybrid scheme. The result is an extremely flexible solution that adjusts to the number of available nodes, processors and memory, and consequently performs well on a wide variety of computing architectures.

Performance Analysis of GYRO: A Tool Evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Worley, P.; Roth, P.; Candy, J.

2005-06-26

The performance of the Eulerian gyrokinetic-Maxwell solver code GYRO is analyzed on five high performance computing systems. First, a manual approach is taken, using custom scripts to analyze the output of embedded wall clock timers, floating point operation counts collected using hardware performance counters, and traces of user and communication events collected using the profiling interface to Message Passing Interface (MPI) libraries. Parts of the analysis are then repeated or extended using a number of sophisticated performance analysis tools: IPM, KOJAK, SvPablo, TAU, and the PMaC modeling tool suite. The paper briefly discusses what has been discovered via this manualmore » analysis process, what performance analyses are inconvenient or infeasible to attempt manually, and to what extent the tools show promise in accelerating or significantly extending the manual performance analyses.« less

Spot: A Programming Language for Verified Flight Software

NASA Technical Reports Server (NTRS)

Bocchino, Robert L., Jr.; Gamble, Edward; Gostelow, Kim P.; Some, Raphael R.

2014-01-01

The C programming language is widely used for programming space flight software and other safety-critical real time systems. C, however, is far from ideal for this purpose: as is well known, it is both low-level and unsafe. This paper describes Spot, a language derived from C for programming space flight systems. Spot aims to maintain compatibility with existing C code while improving the language and supporting verification with the SPIN model checker. The major features of Spot include actor-based concurrency, distributed state with message passing and transactional updates, and annotations for testing and verification. Spot also supports domain-specific annotations for managing spacecraft state, e.g., communicating telemetry information to the ground. We describe the motivation and design rationale for Spot, give an overview of the design, provide examples of Spot's capabilities, and discuss the current status of the implementation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gorentla Venkata, Manjunath; Graham, Richard L; Ladd, Joshua S

This paper describes the design and implementation of InfiniBand (IB) CORE-Direct based blocking and nonblocking broadcast operations within the Cheetah collective operation framework. It describes a novel approach that fully ofFLoads collective operations and employs only user-supplied buffers. For a 64 rank communicator, the latency of CORE-Direct based hierarchical algorithm is better than production-grade Message Passing Interface (MPI) implementations, 150% better than the default Open MPI algorithm and 115% better than the shared memory optimized MVAPICH implementation for a one kilobyte (KB) message, and for eight mega-bytes (MB) it is 48% and 64% better, respectively. Flat-topology broadcast achieves 99.9% overlapmore » in a polling based communication-computation test, and 95.1% overlap for a wait based test, compared with 92.4% and 17.0%, respectively, for a similar Central Processing Unit (CPU) based implementation.« less

MPI, HPF or OpenMP: A Study with the NAS Benchmarks

NASA Technical Reports Server (NTRS)

Jin, Hao-Qiang; Frumkin, Michael; Hribar, Michelle; Waheed, Abdul; Yan, Jerry; Saini, Subhash (Technical Monitor)

1999-01-01

Porting applications to new high performance parallel and distributed platforms is a challenging task. Writing parallel code by hand is time consuming and costly, but the task can be simplified by high level languages and would even better be automated by parallelizing tools and compilers. The definition of HPF (High Performance Fortran, based on data parallel model) and OpenMP (based on shared memory parallel model) standards has offered great opportunity in this respect. Both provide simple and clear interfaces to language like FORTRAN and simplify many tedious tasks encountered in writing message passing programs. In our study we implemented the parallel versions of the NAS Benchmarks with HPF and OpenMP directives. Comparison of their performance with the MPI implementation and pros and cons of different approaches will be discussed along with experience of using computer-aided tools to help parallelize these benchmarks. Based on the study,potentials of applying some of the techniques to realistic aerospace applications will be presented

MPI, HPF or OpenMP: A Study with the NAS Benchmarks

NASA Technical Reports Server (NTRS)

Jin, H.; Frumkin, M.; Hribar, M.; Waheed, A.; Yan, J.; Saini, Subhash (Technical Monitor)

1999-01-01

Porting applications to new high performance parallel and distributed platforms is a challenging task. Writing parallel code by hand is time consuming and costly, but this task can be simplified by high level languages and would even better be automated by parallelizing tools and compilers. The definition of HPF (High Performance Fortran, based on data parallel model) and OpenMP (based on shared memory parallel model) standards has offered great opportunity in this respect. Both provide simple and clear interfaces to language like FORTRAN and simplify many tedious tasks encountered in writing message passing programs. In our study, we implemented the parallel versions of the NAS Benchmarks with HPF and OpenMP directives. Comparison of their performance with the MPI implementation and pros and cons of different approaches will be discussed along with experience of using computer-aided tools to help parallelize these benchmarks. Based on the study, potentials of applying some of the techniques to realistic aerospace applications will be presented.

Efficient iteration in data-parallel programs with irregular and dynamically distributed data structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Littlefield, R.J.

1990-02-01

To implement an efficient data-parallel program on a non-shared memory MIMD multicomputer, data and computations must be properly partitioned to achieve good load balance and locality of reference. Programs with irregular data reference patterns often require irregular partitions. Although good partitions may be easy to determine, they can be difficult or impossible to implement in programming languages that provide only regular data distributions, such as blocked or cyclic arrays. We are developing Onyx, a programming system that provides a shared memory model of distributed data structures and extends the concept of data distribution to include irregular and dynamic distributions. Thismore » provides a powerful means to specify irregular partitions. Perhaps surprisingly, programs using it can also execute efficiently. In this paper, we describe and evaluate the Onyx implementation of a model problem that repeatedly executes an irregular but fixed data reference pattern. On an NCUBE hypercube, the speed of the Onyx implementation is comparable to that of carefully handwritten message-passing code.« less

High-performance parallel approaches for three-dimensional light detection and ranging point clouds gridding

NASA Astrophysics Data System (ADS)

Rizki, Permata Nur Miftahur; Lee, Heezin; Lee, Minsu; Oh, Sangyoon

2017-01-01

With the rapid advance of remote sensing technology, the amount of three-dimensional point-cloud data has increased extraordinarily, requiring faster processing in the construction of digital elevation models. There have been several attempts to accelerate the computation using parallel methods; however, little attention has been given to investigating different approaches for selecting the most suited parallel programming model for a given computing environment. We present our findings and insights identified by implementing three popular high-performance parallel approaches (message passing interface, MapReduce, and GPGPU) on time demanding but accurate kriging interpolation. The performances of the approaches are compared by varying the size of the grid and input data. In our empirical experiment, we demonstrate the significant acceleration by all three approaches compared to a C-implemented sequential-processing method. In addition, we also discuss the pros and cons of each method in terms of usability, complexity infrastructure, and platform limitation to give readers a better understanding of utilizing those parallel approaches for gridding purposes.

Accelerating three-dimensional FDTD calculations on GPU clusters for electromagnetic field simulation.

PubMed

Nagaoka, Tomoaki; Watanabe, Soichi

2012-01-01

Electromagnetic simulation with anatomically realistic computational human model using the finite-difference time domain (FDTD) method has recently been performed in a number of fields in biomedical engineering. To improve the method's calculation speed and realize large-scale computing with the computational human model, we adapt three-dimensional FDTD code to a multi-GPU cluster environment with Compute Unified Device Architecture and Message Passing Interface. Our multi-GPU cluster system consists of three nodes. The seven GPU boards (NVIDIA Tesla C2070) are mounted on each node. We examined the performance of the FDTD calculation on multi-GPU cluster environment. We confirmed that the FDTD calculation on the multi-GPU clusters is faster than that on a multi-GPU (a single workstation), and we also found that the GPU cluster system calculate faster than a vector supercomputer. In addition, our GPU cluster system allowed us to perform the large-scale FDTD calculation because were able to use GPU memory of over 100 GB.

Performance Characteristics of the Multi-Zone NAS Parallel Benchmarks

NASA Technical Reports Server (NTRS)

Jin, Haoqiang; VanderWijngaart, Rob F.

2003-01-01

We describe a new suite of computational benchmarks that models applications featuring multiple levels of parallelism. Such parallelism is often available in realistic flow computations on systems of grids, but had not previously been captured in bench-marks. The new suite, named NPB Multi-Zone, is extended from the NAS Parallel Benchmarks suite, and involves solving the application benchmarks LU, BT and SP on collections of loosely coupled discretization meshes. The solutions on the meshes are updated independently, but after each time step they exchange boundary value information. This strategy provides relatively easily exploitable coarse-grain parallelism between meshes. Three reference implementations are available: one serial, one hybrid using the Message Passing Interface (MPI) and OpenMP, and another hybrid using a shared memory multi-level programming model (SMP+OpenMP). We examine the effectiveness of hybrid parallelization paradigms in these implementations on three different parallel computers. We also use an empirical formula to investigate the performance characteristics of the multi-zone benchmarks.

A smart room for hospitalised elderly people: essay of modelling and first steps of an experiment.

PubMed

Rialle, V; Lauvernay, N; Franco, A; Piquard, J F; Couturier, P

1999-01-01

We present a study of modelling and the first steps of an experiment of a smart room for hospitalised elderly people. The system aims at detecting falls and sicknesses, and implements four main functions: perception of patient and environment through sensors, reasoning from perceived events and patient clinical findings, action by way of alarm triggering and message passing to medical staff, and adaptation to various patient profiles, sensor layouts, house fixtures and architecture. It includes a physical multisensory device located in the patient's room, and a multi-agent system for fall detection and alarm triggering. This system encompasses a perception agent, and a reasoning agent. The latter has two complementary capacities implemented by sub-agents: deduction of type of alarm from incoming events, and knowledge induction from recorded events. The system has been tested with a few patients in real clinical situation, and the first experiment provides encouraging results which are described in a precise manner.

Performance and Application of Parallel OVERFLOW Codes on Distributed and Shared Memory Platforms

NASA Technical Reports Server (NTRS)

Djomehri, M. Jahed; Rizk, Yehia M.

1999-01-01

The presentation discusses recent studies on the performance of the two parallel versions of the aerodynamics CFD code, OVERFLOW_MPI and _MLP. Developed at NASA Ames, the serial version, OVERFLOW, is a multidimensional Navier-Stokes flow solver based on overset (Chimera) grid technology. The code has recently been parallelized in two ways. One is based on the explicit message-passing interface (MPI) across processors and uses the _MPI communication package. This approach is primarily suited for distributed memory systems and workstation clusters. The second, termed the multi-level parallel (MLP) method, is simple and uses shared memory for all communications. The _MLP code is suitable on distributed-shared memory systems. For both methods, the message passing takes place across the processors or processes at the advancement of each time step. This procedure is, in effect, the Chimera boundary conditions update, which is done in an explicit "Jacobi" style. In contrast, the update in the serial code is done in more of the "Gauss-Sidel" fashion. The programming efforts for the _MPI code is more complicated than for the _MLP code; the former requires modification of the outer and some inner shells of the serial code, whereas the latter focuses only on the outer shell of the code. The _MPI version offers a great deal of flexibility in distributing grid zones across a specified number of processors in order to achieve load balancing. The approach is capable of partitioning zones across multiple processors or sending each zone and/or cluster of several zones into a single processor. The message passing across the processors consists of Chimera boundary and/or an overlap of "halo" boundary points for each partitioned zone. The MLP version is a new coarse-grain parallel concept at the zonal and intra-zonal levels. A grouping strategy is used to distribute zones into several groups forming sub-processes which will run in parallel. The total volume of grid points in each group are approximately balanced. A proper number of threads are initially allocated to each group, and in subsequent iterations during the run-time, the number of threads are adjusted to achieve load balancing across the processes. Each process exploits the multitasking directives already established in Overflow.

Language Implications for Advertising in International Markets: A Model for Message Content and Message Execution.

ERIC Educational Resources Information Center

Beard, John; Yaprak, Attila

A content analysis model for assessing advertising themes and messages generated primarily for United States markets to overcome barriers in the cultural environment of international markets was developed and tested. The model is based on three primary categories for generating, evaluating, and executing advertisements: rational, emotional, and…

Evaluation of Sexual Communication Message Strategies

PubMed Central

2011-01-01

Parent-child communication about sex is an important proximal reproductive health outcome. But while campaigns to promote it such as the Parents Speak Up National Campaign (PSUNC) have been effective, little is known about how messages influence parental cognitions and behavior. This study examines which message features explain responses to sexual communication messages. We content analyzed 4 PSUNC ads to identify specific, measurable message and advertising execution features. We then develop quantitative measures of those features, including message strategies, marketing strategies, and voice and other stylistic features, and merged the resulting data into a dataset drawn from a national media tracking survey of the campaign. Finally, we conducted multivariable logistic regression models to identify relationships between message content and ad reactions/receptivity, and between ad reactions/receptivity and parents' cognitions related to sexual communication included in the campaign's conceptual model. We found that overall parents were highly receptive to the PSUNC ads. We did not find significant associations between message content and ad reactions/receptivity. However, we found that reactions/receptivity to specific PSUNC ads were associated with increased norms, self-efficacy, short- and long-term expectations about parent-child sexual communication, as theorized in the conceptual model. This study extends previous research and methods to analyze message content and reactions/receptivity. The results confirm and extend previous PSUNC campaign evaluation and provide further evidence for the conceptual model. Future research should examine additional message content features and the effects of reactions/receptivity. PMID:21599875

I spy with my little eye: cognitive processing of framed physical activity messages.

PubMed

Bassett-Gunter, Rebecca L; Latimer-Cheung, Amy E; Martin Ginis, Kathleen A; Castelhano, Monica

2014-01-01

The primary purpose was to examine the relative cognitive processing of gain-framed versus loss-framed physical activity messages following exposure to health risk information. Guided by the Extended Parallel Process Model, the secondary purpose was to examine the relation between dwell time, message recall, and message-relevant thoughts, as well as perceived risk, personal relevance, and fear arousal. Baseline measures of perceived risk for inactivity-related disease and health problems were administered to 77 undergraduate students. Participants read population-specific health risk information while wearing a head-mounted eye tracker, which measured dwell time on message content. Perceived risk was then reassessed. Next, participants read PA messages while the eye tracker measured dwell time on message content. Immediately following message exposure, recall, thought-listing, fear arousal, and personal relevance were measured. Dwell time on gain-framed messages was significantly greater than loss-framed messages. However, message recall and thought-listing did not differ by message frame. Dwell time was not significantly related to recall or thought-listing. Consistent with the Extended Parallel Process Model, fear arousal was significantly related to recall, thought-listing, and personal relevance. In conclusion, gain-framed messages may evoke greater dwell time than loss-famed messages. However, dwell time alone may be insufficient for evoking further cognitive processing.

Formative Research regarding Kidney Disease Health Information in a Latino American Sample: Associations among Message Frame, Threat, Efficacy, Message Effectiveness, and Behavioral Intention

ERIC Educational Resources Information Center

Maguire, Katheryn C.; Gardner, Jay; Sopory, Pradeep; Jian, Guowei; Roach, Marcia; Amschlinger, Joe; Moreno, Marcia; Pettey, Gary; Piccone, Gianfranco

2010-01-01

Using prospect theory and the extended parallel process model, this study examined the effect of gain/loss message framing on perceptions of severity, susceptibility, response efficacy, and self efficacy (derived from the extended parallel process model), as well as perception of message effectiveness and behavioral intention in a community based…

The amplification of risk in experimental diffusion chains.

PubMed

Moussaïd, Mehdi; Brighton, Henry; Gaissmaier, Wolfgang

2015-05-05

Understanding how people form and revise their perception of risk is central to designing efficient risk communication methods, eliciting risk awareness, and avoiding unnecessary anxiety among the public. However, public responses to hazardous events such as climate change, contagious outbreaks, and terrorist threats are complex and difficult-to-anticipate phenomena. Although many psychological factors influencing risk perception have been identified in the past, it remains unclear how perceptions of risk change when propagated from one person to another and what impact the repeated social transmission of perceived risk has at the population scale. Here, we study the social dynamics of risk perception by analyzing how messages detailing the benefits and harms of a controversial antibacterial agent undergo change when passed from one person to the next in 10-subject experimental diffusion chains. Our analyses show that when messages are propagated through the diffusion chains, they tend to become shorter, gradually inaccurate, and increasingly dissimilar between chains. In contrast, the perception of risk is propagated with higher fidelity due to participants manipulating messages to fit their preconceptions, thereby influencing the judgments of subsequent participants. Computer simulations implementing this simple influence mechanism show that small judgment biases tend to become more extreme, even when the injected message contradicts preconceived risk judgments. Our results provide quantitative insights into the social amplification of risk perception, and can help policy makers better anticipate and manage the public response to emerging threats.

The amplification of risk in experimental diffusion chains

PubMed Central

Moussaïd, Mehdi; Brighton, Henry; Gaissmaier, Wolfgang

2015-01-01

Understanding how people form and revise their perception of risk is central to designing efficient risk communication methods, eliciting risk awareness, and avoiding unnecessary anxiety among the public. However, public responses to hazardous events such as climate change, contagious outbreaks, and terrorist threats are complex and difficult-to-anticipate phenomena. Although many psychological factors influencing risk perception have been identified in the past, it remains unclear how perceptions of risk change when propagated from one person to another and what impact the repeated social transmission of perceived risk has at the population scale. Here, we study the social dynamics of risk perception by analyzing how messages detailing the benefits and harms of a controversial antibacterial agent undergo change when passed from one person to the next in 10-subject experimental diffusion chains. Our analyses show that when messages are propagated through the diffusion chains, they tend to become shorter, gradually inaccurate, and increasingly dissimilar between chains. In contrast, the perception of risk is propagated with higher fidelity due to participants manipulating messages to fit their preconceptions, thereby influencing the judgments of subsequent participants. Computer simulations implementing this simple influence mechanism show that small judgment biases tend to become more extreme, even when the injected message contradicts preconceived risk judgments. Our results provide quantitative insights into the social amplification of risk perception, and can help policy makers better anticipate and manage the public response to emerging threats. PMID:25902519

Object-oriented knowledge representation for expert systems

NASA Technical Reports Server (NTRS)

Scott, Stephen L.

1991-01-01

Object oriented techniques have generated considerable interest in the Artificial Intelligence (AI) community in recent years. This paper discusses an approach for representing expert system knowledge using classes, objects, and message passing. The implementation is in version 4.3 of NASA's C Language Integrated Production System (CLIPS), an expert system tool that does not provide direct support for object oriented design. The method uses programmer imposed conventions and keywords to structure facts, and rules to provide object oriented capabilities.

Temporal Proof Methodologies for Real-Time Systems,

DTIC Science & Technology

1990-09-01

real time systems that communicate either through shared variables or by message passing and real time issues such as time-outs, process priorities (interrupts) and process scheduling. The authors exhibit two styles for the specification of real - time systems . While the first approach uses bounded versions of temporal operators the second approach allows explicit references to time through a special clock variable. Corresponding to two styles of specification the authors present and compare two fundamentally different proof

Advances in Parallel Computing and Databases for Digital Pathology in Cancer Research

DTIC Science & Technology

2016-11-13

these technologies and how we have used them in the past. We are interested in learning more about the needs of clinical pathologists as we continue to...such as image processing and correlation. Further, High Performance Computing (HPC) paradigms such as the Message Passing Interface (MPI) have been...Defense for Research and Engineering. such as pMatlab [4], or bcMPI [5] can significantly reduce the need for deep knowledge of parallel computing. In

Experiences using OpenMP based on Computer Directed Software DSM on a PC Cluster

NASA Technical Reports Server (NTRS)

Hess, Matthias; Jost, Gabriele; Mueller, Matthias; Ruehle, Roland

2003-01-01

In this work we report on our experiences running OpenMP programs on a commodity cluster of PCs running a software distributed shared memory (DSM) system. We describe our test environment and report on the performance of a subset of the NAS Parallel Benchmarks that have been automaticaly parallelized for OpenMP. We compare the performance of the OpenMP implementations with that of their message passing counterparts and discuss performance differences.

Parallel-Processing Test Bed For Simulation Software

NASA Technical Reports Server (NTRS)

Blech, Richard; Cole, Gary; Townsend, Scott

1996-01-01

Second-generation Hypercluster computing system is multiprocessor test bed for research on parallel algorithms for simulation in fluid dynamics, electromagnetics, chemistry, and other fields with large computational requirements but relatively low input/output requirements. Built from standard, off-shelf hardware readily upgraded as improved technology becomes available. System used for experiments with such parallel-processing concepts as message-passing algorithms, debugging software tools, and computational steering. First-generation Hypercluster system described in "Hypercluster Parallel Processor" (LEW-15283).

"Some convincing arguments to pass back to nervous customers": the role of the tobacco retailer in the Australian tobacco industry's smoker reassurance campaign 1950–1978

PubMed Central

Tofler, A; Chapman, S

2003-01-01

Background: Epidemiological studies and reports on smoking and health published in the 1950s and 1960s threatened the tobacco industry worldwide, which acted to reassure smokers and counteract mounting evidence that smoking posed a serious risk to smokers' health. Objective: To document the use of tobacco retailers (1) as a conduit to pass messages of reassurance onto smokers, and (2) to recruit youth and women into smoking. Methods: Review of an extensive collection of Australian tobacco retail trade journals (1950–1978) for articles consistent with the industry's efforts to counter messages about smoking and health, and how to attract non-smokers, particularly youth and women. Results: The main arguments advanced in the journals included the notion that air pollution and other substances cause cancer, that "statistics" did not constitute proof in the tobacco health scare, and that the industry was committed to research into the causes of cancer and into developing a "safer" cigarette. Conclusions: Numerous articles designed to be reiterated to customers were published, arguing against the link between tobacco and ill health. Tobacco retailers, salesmen and retail trade organisations played a significant role in dissembling the tobacco health nexus. Tobacco retail journals may be an important component in tobacco industry misinformation strategies. PMID:14645943

Effects of Message Design Logic on the Communication of Intention.

ERIC Educational Resources Information Center

O'Keefe, Barbara J.; Lambert, Bruce L.

In producing and comprehending messages, a communicator relies on a "message design logic" embodying an individual's knowledge about how to relate message forms and functions. According to this model, there are three different message design logics: (1) expressive, in which self-expression is the chief function, and affective and…

Large Colloids in Cholesteric Liquid Crystals

NASA Astrophysics Data System (ADS)

Stratford, K.; Gray, A.; Lintuvuori, J. S.

2015-12-01

We describe a coarse-grained Landau-de Gennes model of liquid crystals (LCs) including hydrodynamics based on the Beris-Edwards equations. The model is employed to study the impact of large colloids on the long range LC defect structure in the cholesteric LC blue phases. `Large' here means that the particle size is comparable to the cholesteric pitch, the length scale on which the LC order undergoes a helical twist. We investigate the case of a single particle, with either normal or degenerate planar anchoring, placed initially in an equilibrium blue phase LC. It is found that in some cases, well defined steady disclination structure emerges at the particle surface, while in other cases no clear steady state is reached in the simulations, and disclination reorganisation appears to proliferate through the bulk LC. These systems are of potential interest in the context of using LCs to template self-assembly of colloid structure, e.g., for opto-electronic devices. Computationally, we demonstrate a parallel approach using mixed message-passing and threaded model on graphical processing units allows effective and efficient progress for this problem.

Parallel Monte Carlo transport modeling in the context of a time-dependent, three-dimensional multi-physics code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Procassini, R.J.

1997-12-31

The fine-scale, multi-space resolution that is envisioned for accurate simulations of complex weapons systems in three spatial dimensions implies flop-rate and memory-storage requirements that will only be obtained in the near future through the use of parallel computational techniques. Since the Monte Carlo transport models in these simulations usually stress both of these computational resources, they are prime candidates for parallelization. The MONACO Monte Carlo transport package, which is currently under development at LLNL, will utilize two types of parallelism within the context of a multi-physics design code: decomposition of the spatial domain across processors (spatial parallelism) and distribution ofmore » particles in a given spatial subdomain across additional processors (particle parallelism). This implementation of the package will utilize explicit data communication between domains (message passing). Such a parallel implementation of a Monte Carlo transport model will result in non-deterministic communication patterns. The communication of particles between subdomains during a Monte Carlo time step may require a significant level of effort to achieve a high parallel efficiency.« less

Roofline model toolkit: A practical tool for architectural and program analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lo, Yu Jung; Williams, Samuel; Van Straalen, Brian

We present preliminary results of the Roofline Toolkit for multicore, many core, and accelerated architectures. This paper focuses on the processor architecture characterization engine, a collection of portable instrumented micro benchmarks implemented with Message Passing Interface (MPI), and OpenMP used to express thread-level parallelism. These benchmarks are specialized to quantify the behavior of different architectural features. Compared to previous work on performance characterization, these microbenchmarks focus on capturing the performance of each level of the memory hierarchy, along with thread-level parallelism, instruction-level parallelism and explicit SIMD parallelism, measured in the context of the compilers and run-time environments. We also measuremore » sustained PCIe throughput with four GPU memory managed mechanisms. By combining results from the architecture characterization with the Roofline model based solely on architectural specifications, this work offers insights for performance prediction of current and future architectures and their software systems. To that end, we instrument three applications and plot their resultant performance on the corresponding Roofline model when run on a Blue Gene/Q architecture.« less

The effects of fear appeal message repetition on perceived threat, perceived efficacy, and behavioral intention in the extended parallel process model.

PubMed

Shi, Jingyuan Jolie; Smith, Sandi W

2016-01-01

This study examined the effect of moderately repeated exposure (three times) to a fear appeal message on the Extended Parallel Processing Model (EPPM) variables of threat, efficacy, and behavioral intentions for the recommended behaviors in the message, as well as the proportions of systematic and message-related thoughts generated after each message exposure. The results showed that after repeated exposure to a fear appeal message about preventing melanoma, perceived threat in terms of susceptibility and perceived efficacy in terms of response efficacy significantly increased. The behavioral intentions of all recommended behaviors did not change after repeated exposure to the message. However, after the second exposure the proportions of both systematic and all message-related thoughts (relative to total thoughts) significantly decreased while the proportion of heuristic thoughts significantly increased, and this pattern held after the third exposure. The findings demonstrated that the predictions in the EPPM are likely to be operative after three exposures to a persuasive message.

SPOTting Model Parameters Using a Ready-Made Python Package

NASA Astrophysics Data System (ADS)

Houska, Tobias; Kraft, Philipp; Chamorro-Chavez, Alejandro; Breuer, Lutz

2017-04-01

The choice for specific parameter estimation methods is often more dependent on its availability than its performance. We developed SPOTPY (Statistical Parameter Optimization Tool), an open source python package containing a comprehensive set of methods typically used to calibrate, analyze and optimize parameters for a wide range of ecological models. SPOTPY currently contains eight widely used algorithms, 11 objective functions, and can sample from eight parameter distributions. SPOTPY has a model-independent structure and can be run in parallel from the workstation to large computation clusters using the Message Passing Interface (MPI). We tested SPOTPY in five different case studies to parameterize the Rosenbrock, Griewank and Ackley functions, a one-dimensional physically based soil moisture routine, where we searched for parameters of the van Genuchten-Mualem function and a calibration of a biogeochemistry model with different objective functions. The case studies reveal that the implemented SPOTPY methods can be used for any model with just a minimal amount of code for maximal power of parameter optimization. They further show the benefit of having one package at hand that includes number of well performing parameter search methods, since not every case study can be solved sufficiently with every algorithm or every objective function.

SPOTting Model Parameters Using a Ready-Made Python Package.

PubMed

Houska, Tobias; Kraft, Philipp; Chamorro-Chavez, Alejandro; Breuer, Lutz

2015-01-01

The choice for specific parameter estimation methods is often more dependent on its availability than its performance. We developed SPOTPY (Statistical Parameter Optimization Tool), an open source python package containing a comprehensive set of methods typically used to calibrate, analyze and optimize parameters for a wide range of ecological models. SPOTPY currently contains eight widely used algorithms, 11 objective functions, and can sample from eight parameter distributions. SPOTPY has a model-independent structure and can be run in parallel from the workstation to large computation clusters using the Message Passing Interface (MPI). We tested SPOTPY in five different case studies to parameterize the Rosenbrock, Griewank and Ackley functions, a one-dimensional physically based soil moisture routine, where we searched for parameters of the van Genuchten-Mualem function and a calibration of a biogeochemistry model with different objective functions. The case studies reveal that the implemented SPOTPY methods can be used for any model with just a minimal amount of code for maximal power of parameter optimization. They further show the benefit of having one package at hand that includes number of well performing parameter search methods, since not every case study can be solved sufficiently with every algorithm or every objective function.

SPOTting Model Parameters Using a Ready-Made Python Package

PubMed Central

Houska, Tobias; Kraft, Philipp; Chamorro-Chavez, Alejandro; Breuer, Lutz

2015-01-01

The choice for specific parameter estimation methods is often more dependent on its availability than its performance. We developed SPOTPY (Statistical Parameter Optimization Tool), an open source python package containing a comprehensive set of methods typically used to calibrate, analyze and optimize parameters for a wide range of ecological models. SPOTPY currently contains eight widely used algorithms, 11 objective functions, and can sample from eight parameter distributions. SPOTPY has a model-independent structure and can be run in parallel from the workstation to large computation clusters using the Message Passing Interface (MPI). We tested SPOTPY in five different case studies to parameterize the Rosenbrock, Griewank and Ackley functions, a one-dimensional physically based soil moisture routine, where we searched for parameters of the van Genuchten-Mualem function and a calibration of a biogeochemistry model with different objective functions. The case studies reveal that the implemented SPOTPY methods can be used for any model with just a minimal amount of code for maximal power of parameter optimization. They further show the benefit of having one package at hand that includes number of well performing parameter search methods, since not every case study can be solved sufficiently with every algorithm or every objective function. PMID:26680783

Numerical Modeling of 3D Seismic Wave Propagation around Yogyakarta, the Southern Part of Central Java, Indonesia, Using Spectral-Element Method on MPI-GPU Cluster

NASA Astrophysics Data System (ADS)

Sudarmaji; Rudianto, Indra; Eka Nurcahya, Budi

2018-04-01

A strong tectonic earthquake with a magnitude of 5.9 Richter scale has been occurred in Yogyakarta and Central Java on May 26, 2006. The earthquake has caused severe damage in Yogyakarta and the southern part of Central Java, Indonesia. The understanding of seismic response of earthquake among ground shaking and the level of building damage is important. We present numerical modeling of 3D seismic wave propagation around Yogyakarta and the southern part of Central Java using spectral-element method on MPI-GPU (Graphics Processing Unit) computer cluster to observe its seismic response due to the earthquake. The homogeneous 3D realistic model is generated with detailed topography surface. The influences of free surface topography and layer discontinuity of the 3D model among the seismic response are observed. The seismic wave field is discretized using spectral-element method. The spectral-element method is solved on a mesh of hexahedral elements that is adapted to the free surface topography and the internal discontinuity of the model. To increase the data processing capabilities, the simulation is performed on a GPU cluster with implementation of MPI (Message Passing Interface).

Factors influencing message dissemination through social media

NASA Astrophysics Data System (ADS)

Zheng, Zeyu; Yang, Huancheng; Fu, Yang; Fu, Dianzheng; Podobnik, Boris; Stanley, H. Eugene

2018-06-01

Online social networks strongly impact our daily lives. An internet user (a "Netizen") wants messages to be efficiently disseminated. The susceptible-infected-recovered (SIR) dissemination model is the traditional tool for exploring the spreading mechanism of information diffusion. We here test our SIR-based dissemination model on open and real-world data collected from Twitter. We locate and identify phase transitions in the message dissemination process. We find that message content is a stronger factor than the popularity of the sender. We also find that the probability that a message will be forwarded has a threshold that affects its ability to spread, and when the probability is above the threshold the message quickly achieves mass dissemination.

Scientific Message Translation and the Heuristic Systematic Model: Insights for Designing Educational Messages About Progesterone and Breast Cancer Risks

PubMed Central

Perrault, Evan; Smith, Sandi; Keating, David M.; Nazione, Samantha; Silk, Kami; Russell, Jessica

2017-01-01

Results of ongoing scientific research on environmental determinants of breast cancer are not typically presented to the public in ways they can easily understand and use to take preventive actions. In this study, results of scientific studies on progesterone exposure as a risk factor for breast cancer were translated into high and low literacy level messages. Using the heuristic systematic model, this study examined how ability, motivation, and message processing (heuristic and systematic) influenced perceptions of risk beliefs and negative attitudes about progesterone exposure among women who read the translated scientific messages. Among the 1254 participants, those given the higher literacy level message had greater perceptions of risk about progesterone. Heuristic message cues of source credibility and perceived message quality, as well as motivation, also predicted risk beliefs. Finally, risk beliefs were a strong predictor of negative attitudes about exposure to progesterone. The results can help improve health education message design in terms of practitioners having better knowledge of message features that are the most persuasive to the target audiences on this topic. PMID:25903053

A software bus for thread objects

NASA Technical Reports Server (NTRS)

Callahan, John R.; Li, Dehuai

1995-01-01

The authors have implemented a software bus for lightweight threads in an object-oriented programming environment that allows for rapid reconfiguration and reuse of thread objects in discrete-event simulation experiments. While previous research in object-oriented, parallel programming environments has focused on direct communication between threads, our lightweight software bus, called the MiniBus, provides a means to isolate threads from their contexts of execution by restricting communications between threads to message-passing via their local ports only. The software bus maintains a topology of connections between these ports. It routes, queues, and delivers messages according to this topology. This approach allows for rapid reconfiguration and reuse of thread objects in other systems without making changes to the specifications or source code. A layered approach that provides the needed transparency to developers is presented. Examples of using the MiniBus are given, and the value of bus architectures in building and conducting simulations of discrete-event systems is discussed.

An implementation and evaluation of the MPI 3.0 one-sided communication interface

DOE PAGES

Dinan, James S.; Balaji, Pavan; Buntinas, Darius T.; ...

2016-01-09

The Q1 Message Passing Interface (MPI) 3.0 standard includes a significant revision to MPI’s remote memory access (RMA) interface, which provides support for one-sided communication. MPI-3 RMA is expected to greatly enhance the usability and performance ofMPI RMA.We present the first complete implementation of MPI-3 RMA and document implementation techniques and performance optimization opportunities enabled by the new interface. Our implementation targets messaging-based networks and is publicly available in the latest release of the MPICH MPI implementation. Here using this implementation, we explore the performance impact of new MPI-3 functionality and semantics. Results indicate that the MPI-3 RMA interface providesmore » significant advantages over the MPI-2 interface by enabling increased communication concurrency through relaxed semantics in the interface and additional routines that provide new window types, synchronization modes, and atomic operations.« less

An implementation and evaluation of the MPI 3.0 one-sided communication interface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dinan, James S.; Balaji, Pavan; Buntinas, Darius T.

The Q1 Message Passing Interface (MPI) 3.0 standard includes a significant revision to MPI’s remote memory access (RMA) interface, which provides support for one-sided communication. MPI-3 RMA is expected to greatly enhance the usability and performance ofMPI RMA.We present the first complete implementation of MPI-3 RMA and document implementation techniques and performance optimization opportunities enabled by the new interface. Our implementation targets messaging-based networks and is publicly available in the latest release of the MPICH MPI implementation. Here using this implementation, we explore the performance impact of new MPI-3 functionality and semantics. Results indicate that the MPI-3 RMA interface providesmore » significant advantages over the MPI-2 interface by enabling increased communication concurrency through relaxed semantics in the interface and additional routines that provide new window types, synchronization modes, and atomic operations.« less

Non-invasive lightweight integration engine for building EHR from autonomous distributed systems.

PubMed

Angulo, Carlos; Crespo, Pere; Maldonado, José A; Moner, David; Pérez, Daniel; Abad, Irene; Mandingorra, Jesús; Robles, Montserrat

2007-12-01

In this paper we describe Pangea-LE, a message-oriented lightweight data integration engine that allows homogeneous and concurrent access to clinical information from disperse and heterogeneous data sources. The engine extracts the information and passes it to the requesting client applications in a flexible XML format. The XML response message can be formatted on demand by appropriate Extensible Stylesheet Language (XSL) transformations in order to meet the needs of client applications. We also present a real deployment in a hospital where Pangea-LE collects and generates an XML view of all the available patient clinical information. The information is presented to healthcare professionals in an Electronic Health Record (EHR) viewer Web application with patient search and EHR browsing capabilities. Implantation in a real setting has been a success due to the non-invasive nature of Pangea-LE which respects the existing information systems.

The equipment access software for a distributed UNIX-based accelerator control system

NASA Astrophysics Data System (ADS)

Trofimov, Nikolai; Zelepoukine, Serguei; Zharkov, Eugeny; Charrue, Pierre; Gareyte, Claire; Poirier, Hervé

1994-12-01

This paper presents a generic equipment access software package for a distributed control system using computers with UNIX or UNIX-like operating systems. The package consists of three main components, an application Equipment Access Library, Message Handler and Equipment Data Base. An application task, which may run in any computer in the network, sends requests to access equipment through Equipment Library calls. The basic request is in the form Equipment-Action-Data and is routed via a remote procedure call to the computer to which the given equipment is connected. In this computer the request is received by the Message Handler. According to the type of the equipment connection, the Message Handler either passes the request to the specific process software in the same computer or forwards it to a lower level network of equipment controllers using MIL1553B, GPIB, RS232 or BITBUS communication. The answer is then returned to the calling application. Descriptive information required for request routing and processing is stored in the real-time Equipment Data Base. The package has been written to be portable and is currently available on DEC Ultrix, LynxOS, HPUX, XENIX, OS-9 and Apollo domain.

An Application of Epidemiological Modeling to Information Diffusion

NASA Astrophysics Data System (ADS)

McCormack, Robert; Salter, William

Messages often spread within a population through unofficial - particularly web-based - media. Such ideas have been termed "memes." To impede the flow of terrorist messages and to promote counter messages within a population, intelligence analysts must understand how messages spread. We used statistical language processing technologies to operationalize "memes" as latent topics in electronic text and applied epidemiological techniques to describe and analyze patterns of message propagation. We developed our methods and applied them to English-language newspapers and blogs in the Arab world. We found that a relatively simple epidemiological model can reproduce some dynamics of observed empirical relationships.

PANDA: A distributed multiprocessor operating system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chubb, P.

1989-01-01

PANDA is a design for a distributed multiprocessor and an operating system. PANDA is designed to allow easy expansion of both hardware and software. As such, the PANDA kernel provides only message passing and memory and process management. The other features needed for the system (device drivers, secondary storage management, etc.) are provided as replaceable user tasks. The thesis presents PANDA's design and implementation, both hardware and software. PANDA uses multiple 68010 processors sharing memory on a VME bus, each such node potentially connected to others via a high speed network. The machine is completely homogeneous: there are no differencesmore » between processors that are detectable by programs running on the machine. A single two-processor node has been constructed. Each processor contains memory management circuits designed to allow processors to share page tables safely. PANDA presents a programmers' model similar to the hardware model: a job is divided into multiple tasks, each having its own address space. Within each task, multiple processes share code and data. Tasks can send messages to each other, and set up virtual circuits between themselves. Peripheral devices such as disc drives are represented within PANDA by tasks. PANDA divides secondary storage into volumes, each volume being accessed by a volume access task, or VAT. All knowledge about the way that data is stored on a disc is kept in its volume's VAT. The design is such that PANDA should provide a useful testbed for file systems and device drivers, as these can be installed without recompiling PANDA itself, and without rebooting the machine.« less

Accelerating atomistic calculations of quantum energy eigenstates on graphic cards

NASA Astrophysics Data System (ADS)

Rodrigues, Walter; Pecchia, A.; Lopez, M.; Auf der Maur, M.; Di Carlo, A.

2014-10-01

Electronic properties of nanoscale materials require the calculation of eigenvalues and eigenvectors of large matrices. This bottleneck can be overcome by parallel computing techniques or the introduction of faster algorithms. In this paper we report a custom implementation of the Lanczos algorithm with simple restart, optimized for graphical processing units (GPUs). The whole algorithm has been developed using CUDA and runs entirely on the GPU, with a specialized implementation that spares memory and reduces at most machine-to-device data transfers. Furthermore parallel distribution over several GPUs has been attained using the standard message passing interface (MPI). Benchmark calculations performed on a GaN/AlGaN wurtzite quantum dot with up to 600,000 atoms are presented. The empirical tight-binding (ETB) model with an sp3d5s∗+spin-orbit parametrization has been used to build the system Hamiltonian (H).

Distributed computing for membrane-based modeling of action potential propagation.

PubMed

Porras, D; Rogers, J M; Smith, W M; Pollard, A E

2000-08-01

Action potential propagation simulations with physiologic membrane currents and macroscopic tissue dimensions are computationally expensive. We, therefore, analyzed distributed computing schemes to reduce execution time in workstation clusters by parallelizing solutions with message passing. Four schemes were considered in two-dimensional monodomain simulations with the Beeler-Reuter membrane equations. Parallel speedups measured with each scheme were compared to theoretical speedups, recognizing the relationship between speedup and code portions that executed serially. A data decomposition scheme based on total ionic current provided the best performance. Analysis of communication latencies in that scheme led to a load-balancing algorithm in which measured speedups at 89 +/- 2% and 75 +/- 8% of theoretical speedups were achieved in homogeneous and heterogeneous clusters of workstations. Speedups in this scheme with the Luo-Rudy dynamic membrane equations exceeded 3.0 with eight distributed workstations. Cluster speedups were comparable to those measured during parallel execution on a shared memory machine.

Multicore Challenges and Benefits for High Performance Scientific Computing

DOE PAGES

Nielsen, Ida M. B.; Janssen, Curtis L.

2008-01-01

Until recently, performance gains in processors were achieved largely by improvements in clock speeds and instruction level parallelism. Thus, applications could obtain performance increases with relatively minor changes by upgrading to the latest generation of computing hardware. Currently, however, processor performance improvements are realized by using multicore technology and hardware support for multiple threads within each core, and taking full advantage of this technology to improve the performance of applications requires exposure of extreme levels of software parallelism. We will here discuss the architecture of parallel computers constructed from many multicore chips as well as techniques for managing the complexitymore » of programming such computers, including the hybrid message-passing/multi-threading programming model. We will illustrate these ideas with a hybrid distributed memory matrix multiply and a quantum chemistry algorithm for energy computation using Møller–Plesset perturbation theory.« less

Tolerant (parallel) Programming

NASA Technical Reports Server (NTRS)

DiNucci, David C.; Bailey, David H. (Technical Monitor)

1997-01-01

In order to be truly portable, a program must be tolerant of a wide range of development and execution environments, and a parallel program is just one which must be tolerant of a very wide range. This paper first defines the term "tolerant programming", then describes many layers of tools to accomplish it. The primary focus is on F-Nets, a formal model for expressing computation as a folded partial-ordering of operations, thereby providing an architecture-independent expression of tolerant parallel algorithms. For implementing F-Nets, Cooperative Data Sharing (CDS) is a subroutine package for implementing communication efficiently in a large number of environments (e.g. shared memory and message passing). Software Cabling (SC), a very-high-level graphical programming language for building large F-Nets, possesses many of the features normally expected from today's computer languages (e.g. data abstraction, array operations). Finally, L2(sup 3) is a CASE tool which facilitates the construction, compilation, execution, and debugging of SC programs.

Discrete sensitivity derivatives of the Navier-Stokes equations with a parallel Krylov solver

NASA Technical Reports Server (NTRS)

Ajmani, Kumud; Taylor, Arthur C., III

1994-01-01

This paper solves an 'incremental' form of the sensitivity equations derived by differentiating the discretized thin-layer Navier Stokes equations with respect to certain design variables of interest. The equations are solved with a parallel, preconditioned Generalized Minimal RESidual (GMRES) solver on a distributed-memory architecture. The 'serial' sensitivity analysis code is parallelized by using the Single Program Multiple Data (SPMD) programming model, domain decomposition techniques, and message-passing tools. Sensitivity derivatives are computed for low and high Reynolds number flows over a NACA 1406 airfoil on a 32-processor Intel Hypercube, and found to be identical to those computed on a single-processor Cray Y-MP. It is estimated that the parallel sensitivity analysis code has to be run on 40-50 processors of the Intel Hypercube in order to match the single-processor processing time of a Cray Y-MP.

Behavior of Flotsam in the California Current System Utilizing Surface Drift of RAFOS Floats

DTIC Science & Technology

2012-09-01

drifter is most widely used (Lumpkin and Pazos 2006). The evolution and construction of the SVP drifter is described by Lumpkin and Pazos (2006). SVP...weight them down so that they were almost submerged in order to reduce the effect of the wind force on drifting objects (Lumpkin and Pazos 2007...by Argos (2011) and Lumpkin and Pazos (2007). As the satellite passes over the drifter, it begins receiving messages. To calculate the drifter’s

Proof of Concept for the Rewrite Rule Machine: Interensemble Studies

DTIC Science & Technology

1994-02-23

34 -,,, S2 •fbo fibo 0 1 Figure 1: Concurrent Rewriting of Fibonacci Expressions exploit a problem’s parallelism at several levels. We call this...property multigrain concurrency; it makes the RRM very well suited for solving not only homogeneous problems, but also complex, locally homogeneous but...interprocessor message passing over a network-is not well suited to data parallelism. A key goal of the RRM is to combine the best of these two approaches in a

Alexander George Karczmar (1917-2017).

PubMed

Soreq, Hermona; Silman, Israel

2017-12-01

The neurochemistry community at large and the Advisory Board of The International Symposia on Cholinergic Mechanisms mourn the loss of Alexander George Karczmar, the elected Honorary President of these international symposia, who passed away peacefully in his Chicago home at the age of 100 on August 17, 2017. For many of us Alex was the essence of cholinergic signaling, and personified its versatile power to send messages between the brain and the peripheral tissues and organs, and to connect between body and soul. © 2017 International Society for Neurochemistry.

Strategic and Tactical Decision-Making Under Uncertainty

DTIC Science & Technology

2006-01-03

message passing algorithms. In recent work we applied this method to the problem of joint decoding of a low-density parity-check ( LDPC ) code and a partial...Joint Decoding of LDPC Codes and Partial-Response Channels." IEEE Transactions on Communications. Vol. 54, No. 7, 1149-1153, 2006. P. Pakzad and V...Michael I. Jordan PAGES U U U SAPR 20 19b. TELEPHONE NUMBER (Include area code ) 510/642-3806 Standard Form 298 (Rev. 8/98) Prescribed by ANSI Std. Z39.18

NAS Parallel Benchmarks. 2.4

NASA Technical Reports Server (NTRS)

VanderWijngaart, Rob; Biegel, Bryan A. (Technical Monitor)

2002-01-01

We describe a new problem size, called Class D, for the NAS Parallel Benchmarks (NPB), whose MPI source code implementation is being released as NPB 2.4. A brief rationale is given for how the new class is derived. We also describe the modifications made to the MPI (Message Passing Interface) implementation to allow the new class to be run on systems with 32-bit integers, and with moderate amounts of memory. Finally, we give the verification values for the new problem size.

Specification of Fenix MPI Fault Tolerance library version 1.0.1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gamble, Marc; Van Der Wijngaart, Rob; Teranishi, Keita

This document provides a specification of Fenix, a software library compatible with the Message Passing Interface (MPI) to support fault recovery without application shutdown. The library consists of two modules. The first, termed process recovery , restores an application to a consistent state after it has suffered a loss of one or more MPI processes (ranks). The second specifies functions the user can invoke to store application data in Fenix managed redundant storage, and to retrieve it from that storage after process recovery.

Relay Forward-Link File Management Services (MaROS Phase 2)

NASA Technical Reports Server (NTRS)

Allard, Daniel A.; Wallick, Michael N.; Hy, Franklin H.; Gladden, Roy E.

2013-01-01

This software provides the service-level functionality to manage the delivery of files from a lander mission repository to an orbiter mission repository for eventual spacelink relay by the orbiter asset on a specific communications pass. It provides further functions to deliver and track a set of mission-defined messages detailing lander authorization instructions and orbiter data delivery state. All of the information concerning these transactions is persisted in a database providing a high level of accountability of the forward-link relay process.

8755 Emulator Design

DTIC Science & Technology

1988-12-01

Break Control....................51 8755 I/O Control..................54 Z-100 Control Software................. 55 Pass User Memory...the emulator SRAM and the other is 55 for the target SRAM. If either signal is replaced by the NACK signal the host computer displays an error message...Block Diagram 69 AUU M/M 8 in Fiur[:. cemti Daga 70m F’M I-- ’I ANLAD AMam U52 COMM ow U2 i M.2 " -n ax- U 6_- Figure 2b. Schematic Diagram 71 )-M -A -I

MPI-IO: A Parallel File I/O Interface for MPI Version 0.3

NASA Technical Reports Server (NTRS)

Corbett, Peter; Feitelson, Dror; Hsu, Yarsun; Prost, Jean-Pierre; Snir, Marc; Fineberg, Sam; Nitzberg, Bill; Traversat, Bernard; Wong, Parkson

1995-01-01

Thanks to MPI [9], writing portable message passing parallel programs is almost a reality. One of the remaining problems is file I/0. Although parallel file systems support similar interfaces, the lack of a standard makes developing a truly portable program impossible. Further, the closest thing to a standard, the UNIX file interface, is ill-suited to parallel computing. Working together, IBM Research and NASA Ames have drafted MPI-I0, a proposal to address the portable parallel I/0 problem. In a nutshell, this proposal is based on the idea that I/0 can be modeled as message passing: writing to a file is like sending a message, and reading from a file is like receiving a message. MPI-IO intends to leverage the relatively wide acceptance of the MPI interface in order to create a similar I/0 interface. The above approach can be materialized in different ways. The current proposal represents the result of extensive discussions (and arguments), but is by no means finished. Many changes can be expected as additional participants join the effort to define an interface for portable I/0. This document is organized as follows. The remainder of this section includes a discussion of some issues that have shaped the style of the interface. Section 2 presents an overview of MPI-IO as it is currently defined. It specifies what the interface currently supports and states what would need to be added to the current proposal to make the interface more complete and robust. The next seven sections contain the interface definition itself. Section 3 presents definitions and conventions. Section 4 contains functions for file control, most notably open. Section 5 includes functions for independent I/O, both blocking and nonblocking. Section 6 includes functions for collective I/O, both blocking and nonblocking. Section 7 presents functions to support system-maintained file pointers, and shared file pointers. Section 8 presents constructors that can be used to define useful filetypes (the role of filetypes is explained in Section 2 below). Section 9 presents how the error handling mechanism of MPI is supported by the MPI-IO interface. All this is followed by a set of appendices, which contain information about issues that have not been totally resolved yet, and about design considerations. The reader can find there the motivation behind some of our design choices. More information on this would definitely be welcome and will be included in a further release of this document. The first appendix contains a description of MPI-I0's 'hints' structure which is used when opening a file. Appendix B is a discussion of various issues in the support for file pointers. Appendix C explains what we mean in talking about atomic access. Appendix D provides detailed examples of filetype constructors, and Appendix E contains a collection of arguments for and against various design decisions.

Flow of Emotional Messages in Artificial Social Networks

NASA Astrophysics Data System (ADS)

Chmiel, Anna; Hołyst, Janusz A.

Models of message flows in an artificial group of users communicating via the Internet are introduced and investigated using numerical simulations. We assumed that messages possess an emotional character with a positive valence and that the willingness to send the next affective message to a given person increases with the number of messages received from this person. As a result, the weights of links between group members evolve over time. Memory effects are introduced, taking into account that the preferential selection of message receivers depends on the communication intensity during the recent period only. We also model the phenomenon of secondary social sharing when the reception of an emotional e-mail triggers the distribution of several emotional e-mails to other people.

NCC Simulation Model: Simulating the operations of the network control center, phase 2

NASA Technical Reports Server (NTRS)

Benjamin, Norman M.; Paul, Arthur S.; Gill, Tepper L.

1992-01-01

The simulation of the network control center (NCC) is in the second phase of development. This phase seeks to further develop the work performed in phase one. Phase one concentrated on the computer systems and interconnecting network. The focus of phase two will be the implementation of the network message dialogues and the resources controlled by the NCC. These resources are requested, initiated, monitored and analyzed via network messages. In the NCC network messages are presented in the form of packets that are routed across the network. These packets are generated, encoded, decoded and processed by the network host processors that generate and service the message traffic on the network that connects these hosts. As a result, the message traffic is used to characterize the work done by the NCC and the connected network. Phase one of the model development represented the NCC as a network of bi-directional single server queues and message generating sources. The generators represented the external segment processors. The served based queues represented the host processors. The NCC model consists of the internal and external processors which generate message traffic on the network that links these hosts. To fully realize the objective of phase two it is necessary to identify and model the processes in each internal processor. These processes live in the operating system of the internal host computers and handle tasks such as high speed message exchanging, ISN and NFE interface, event monitoring, network monitoring, and message logging. Inter process communication is achieved through the operating system facilities. The overall performance of the host is determined by its ability to service messages generated by both internal and external processors.

Evaluation of the implementation of new traceability and food safety requirements in the pig industry in eastern Australia.

PubMed

Hernández-Jover, M; Schembri, N; Toribio, J-A; Holyoake, P K

2009-10-01

To evaluate the implementation and barriers to adoption, among pig producers, of a newly introduced traceability and food safety system in Australia. Implementation of the PigPass national vendor declaration (NVD) linked to an on-farm quality assurance (QA) program was evaluated in May and December 2007 at saleyards and abattoirs in New South Wales, Victoria and Queensland. Four focus group discussions with saleyard producers were held between April and July 2007. Implementation of the PigPass system in terms of accurate completion of the form and QA accreditation was higher at the export abattoir than at the regional saleyard at the first audit (P < 0.01). Implementation increased at the second audit at the abattoirs, but little change with time was observed at saleyards. Approximately half of the producers at saleyards used photocopied PigPass forms, made at least one error (>64%), and many vendors did not appear to be QA-accredited. During focus groups, producers expressed the view that PigPass implementation improved animal and product traceability. They identified the associated costs and a perceived lack of support by information providers as obstacles for adoption. Improvement in the implementation of PigPass among producers marketing pigs at export abattoirs was observed during the 8-month period of the study. There is a need for a more uniform message to producers from government agencies on the importance of the PigPass NVD and QA and extension and education targeted toward producers supplying pigs to saleyards and domestic abattoirs to ensure compliance with the traceability requirements.

Proposal: A Hybrid Dictionary Modelling Approach for Malay Tweet Normalization

NASA Astrophysics Data System (ADS)

Muhamad, Nor Azlizawati Binti; Idris, Norisma; Arshi Saloot, Mohammad

2017-02-01

Malay Twitter message presents a special deviation from the original language. Malay Tweet widely used currently by Twitter users, especially at Malaya archipelago. Thus, it is important to make a normalization system which can translated Malay Tweet language into the standard Malay language. Some researchers have conducted in natural language processing which mainly focuses on normalizing English Twitter messages, while few studies have been done for normalize Malay Tweets. This paper proposes an approach to normalize Malay Twitter messages based on hybrid dictionary modelling methods. This approach normalizes noisy Malay twitter messages such as colloquially language, novel words, and interjections into standard Malay language. This research will be used Language Model and N-grams model.

Message-adjusted network (MAN) hypothesis in gastro-entero-pancreatic (GEP) endocrine system.

PubMed

Aykan, N Faruk

2007-01-01

Several types of communication coordinate body functions to maintain homeostasis. Clarifying intercellular communication systems is as important as intracellular signal mechanisms. In this study, we propose an intercellular network model to establish novel targets in GEP-endocrine system, based on up-to-date information from medical publications. As materials, two physiologic events which are Pavlov's sham-feeding assay and bicarbonate secretion into the duodenum from pancreas were explored by new biologic data from the literature. Major key words used in Pub-Med were modes of regulations (autocrine, paracrine, endocrine, neurocrine, juxtacrine, lumencrine), GEP cells, hormones, peptides and neuro-transmitters. In these two examples of physiologic events, we can design a model of network to clarify transmission of a message. When we take a simple, unique message, we can observe a complete intercellular network. In our examples, these messages are "food is coming" and "hydrogen ions are increasing" in human language (humanese). We need to find molecular counterparts of these unique messages in cell language (cellese). In this network (message-adjusted network; MAN), message is an input which can affect the physiologic equilibrium, mission is an output to improve the disequilibrium and aim is always maintenance of homeostasis. If we orientate to a transmission of a unique message we can distinguish that different cells use different chemical messengers in different modes of regulations to transmit the same message. This study also supports Shannon's information theory and cell language theories such as von Neumann-Patte principles. After human genome project (HU-GO) and protein organisations (HU-PO), finding true messages and the establishment of their networks (in our model HU-MAN project) can be a novel and exciting field in cell biology. We established an intercellular network model to understand intercellular communication in the physiology of GEP endocrine system. This model could help to explain complex physiologic events as well as to generate new treatment concepts.

Exploring a Model of Symbolic Social Communication: The Case of ‘Magic’ Johnson

PubMed Central

FLORA, JUNE A.; SCHOOLER, CAROLINE; MAYS, VICKIE M.; COCHRAN, SUSAN D.

2009-01-01

We propose a model of symbolic social communication to explain the process whereby sociocultural identity mediates relationships among receivers, sources and messages to shape message effects. This exploratory study examines how two at-risk groups of African American men responded to various HIV prevention messages delivered by celebrity and professional sources. We interviewed 47 men from a homeless shelter and 50 male college students. Members of both groups were likely to select Johnson as the best person to deliver HIV prevention messages among a list of African American celebrity and professional sources. Results suggest the symbolic meanings embedded in celebrities and message topics are important and enduring influences on message effects. The images and ideas that a source represents are transferred to the advocated behavior, attitude or knowledge change and thus shape how messages are interpreted and received. Further understanding of how culture influences the effects of persuasive messages is critical for the improvement of health-communication campaigns. PMID:22011997

Evaluation of Smoking Prevention Television Messages Based on the Elaboration Likelihood Model

ERIC Educational Resources Information Center

Flynn, Brian S.; Worden, John K.; Bunn, Janice Yanushka; Connolly, Scott W.; Dorwaldt, Anne L.

2011-01-01

Progress in reducing youth smoking may depend on developing improved methods to communicate with higher risk youth. This study explored the potential of smoking prevention messages based on the Elaboration Likelihood Model (ELM) to address these needs. Structured evaluations of 12 smoking prevention messages based on three strategies derived from…

Refusals and Rejections: Designing Messages to Serve Multiple Goals.

ERIC Educational Resources Information Center

Saeki, Mimako; O'Keefe, Barbara J.

1994-01-01

Tests a rational model of the elaboration of themes found in rejection messages, using Japanese and American participants. Finds partial support for the initial rational model but notes two key revisions: identifies two new themes in rejection messages and suggests substantial differences in the way Americans and Japanese elaborate themes to serve…

Toward Petascale Biologically Plausible Neural Networks

NASA Astrophysics Data System (ADS)

Long, Lyle

This talk will describe an approach to achieving petascale neural networks. Artificial intelligence has been oversold for many decades. Computers in the beginning could only do about 16,000 operations per second. Computer processing power, however, has been doubling every two years thanks to Moore's law, and growing even faster due to massively parallel architectures. Finally, 60 years after the first AI conference we have computers on the order of the performance of the human brain (1016 operations per second). The main issues now are algorithms, software, and learning. We have excellent models of neurons, such as the Hodgkin-Huxley model, but we do not know how the human neurons are wired together. With careful attention to efficient parallel computing, event-driven programming, table lookups, and memory minimization massive scale simulations can be performed. The code that will be described was written in C + + and uses the Message Passing Interface (MPI). It uses the full Hodgkin-Huxley neuron model, not a simplified model. It also allows arbitrary network structures (deep, recurrent, convolutional, all-to-all, etc.). The code is scalable, and has, so far, been tested on up to 2,048 processor cores using 107 neurons and 109 synapses.

Solar wind interaction with Venus and Mars in a parallel hybrid code

NASA Astrophysics Data System (ADS)

Jarvinen, Riku; Sandroos, Arto

2013-04-01

We discuss the development and applications of a new parallel hybrid simulation, where ions are treated as particles and electrons as a charge-neutralizing fluid, for the interaction between the solar wind and Venus and Mars. The new simulation code under construction is based on the algorithm of the sequential global planetary hybrid model developed at the Finnish Meteorological Institute (FMI) and on the Corsair parallel simulation platform also developed at the FMI. The FMI's sequential hybrid model has been used for studies of plasma interactions of several unmagnetized and weakly magnetized celestial bodies for more than a decade. Especially, the model has been used to interpret in situ particle and magnetic field observations from plasma environments of Mars, Venus and Titan. Further, Corsair is an open source MPI (Message Passing Interface) particle and mesh simulation platform, mainly aimed for simulations of diffusive shock acceleration in solar corona and interplanetary space, but which is now also being extended for global planetary hybrid simulations. In this presentation we discuss challenges and strategies of parallelizing a legacy simulation code as well as possible applications and prospects of a scalable parallel hybrid model for the solar wind interactions of Venus and Mars.

Attitudinal Factors Affecting Viral Advertising Pass-On Behaviour of Online Consumers in Food Industry

NASA Astrophysics Data System (ADS)

Mohd Salleh, Nurhidayah; Ariff, Mohd Shoki Md; Zakuan, Norhayati; Sulaiman, Zuraidah; Zameri Mat Saman, Muhamad

2016-05-01

The increase number of active users of social media, especially Facebook, stimulates viral advertising behaviour among them, thus attracting e-marketers to focus on viral advertising in promoting their products. In global market, use of Facebook platform indicated that food services/restaurant of food industry is ranked number 11 with 18.8% users’ response rate within the platform. This development calls for e-marketers in Malaysia to use Facebook as their viral advertising channel. Attitudinal factors affecting the viral advertising pass-on behaviour (VAPB) especially among members of social media is of interest to many researchers. The typical attitudinal factors used were attitude toward social media (ATSM), attitude toward advertising in social media (AASM) and attitude toward advertising in general (AAIG). Attitude toward advertised brand (ATAB) is important in fast food industry because users of social media tend to share their experience about tastes and features of the food. However, ATAB is less emphasized in the conceptual model between attitudinal factors and VAPB. These four factors of consumer attitude served as independent variables in the conceptual model of this study and their effect on viral advertising pass-on behaviour among members of Domino's Pizza Malaysia Facebook page was examined. Online survey using a set of questionnaire which was sent to the members of this group via private message was employed. A total of 254 sets of usable questionnaires were collected from the respondents. All the attitudinal factors, except for AASM, were found to have positive and significant effect on VAPB. AAIG exerted the strongest effect on VAPB. Therefore, e-marketers should emphasize on developing a favourable attitude toward advertising in general among members of a social media to get them involve in viral advertising. In addition, instilling a favourable attitude towards advertised brand is also vital as it influences the members to viral the brand among them. Managerial and theoretical implications of the study are discussed based on the results.

Can anti-speeding messages based on protection motivation theory influence reported speeding intentions?

PubMed

Glendon, A Ian; Walker, Britta L

2013-08-01

The study investigated the effects of anti-speeding messages based on protection motivation theory (PMT) components: severity, vulnerability, rewards, self-efficacy, response efficacy, and response cost, on reported speeding intentions. Eighty-three participants aged 18-25 years holding a current Australian driver's license completed a questionnaire measuring their reported typical and recent speeding behaviors. Comparisons were made between 18 anti-speeding messages used on Australian roads and 18 new anti-speeding messages developed from the PMT model. Participants reported their reactions to the 36 messages on the perceived effectiveness of the message for themselves and for the general population of drivers, and also the likelihood of themselves and other drivers driving within the speed limit after viewing each message. Overall the PMT model-derived anti-speeding messages were better than jurisdiction-use anti-speeding messages in influencing participants' reported intention to drive within the speed limit. Severity and vulnerability were the most effective PMT components for developing anti-speeding messages. Male participants reported significantly lower intention to drive within the speed limit than did female participants. However, males reported significantly higher intention to drive within the speed limit for PMT-derived messages compared with jurisdiction-based messages. Third-person effects were that males reported anti-speeding messages to be more effective for the general driving population than for themselves. Females reported the opposite effect - that all messages would be more effective for themselves than for the general driving population. Findings provided support for using a sound conceptual basis as an effective foundation for anti-speeding message development as well as for evaluating proposed anti-speeding messages on the target driver population. Copyright © 2013 Elsevier Ltd. All rights reserved.

Diagnosing the Causes and Severity of One-sided Message Contention

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tallent, Nathan R.; Vishnu, Abhinav; van Dam, Hubertus

Two trends suggest network contention for one-sided messages is poised to become a performance problem that concerns application developers: an increased interest in one-sided programming models and a rising ratio of hardware threads to network injection bandwidth. Unfortunately, it is difficult to reason about network contention and one-sided messages because one-sided tasks can either decrease or increase contention. We present effective and portable techniques for diagnosing the causes and severity of one-sided message contention. To detect that a message is affected by contention, we maintain statistics representing instantaneous (non-local) network resource demand. Using lightweight measurement and modeling, we identify themore » portion of a message's latency that is due to contention and whether contention occurs at the initiator or target. We attribute these metrics to program statements in their full static and dynamic context. We characterize contention for an important computational chemistry benchmark on InfiniBand, Cray Aries, and IBM Blue Gene/Q interconnects. We pinpoint the sources of contention, estimate their severity, and show that when message delivery time deviates from an ideal model, there are other messages contending for the same network links. With a small change to the benchmark, we reduce contention up to 50% and improve total runtime as much as 20%.« less

Shaping Core Health Messages: Rural, Low-Income Mothers Speak Through Participatory Action Research.

PubMed

Mammen, Sheila; Sano, Yoshie; Braun, Bonnie; Maring, Elisabeth Fost

2018-04-23

Rural, low-income families are disproportionately impacted by health problems owing to structural barriers (e.g., transportation, health insurance coverage) and personal barriers (e.g., health literacy). This paper presents a Participatory Action Research (PAR) model of co-created Core Health Messages (CHMs) in the areas of dental health, food security, health insurance, and physical activity. The research project engaged a multi-disciplinary team of experts to design initial health messages; rural, low-income mothers to respond to, and co-create, health messages; and stakeholders who work with families to share their insights. Findings reveal the perceptions of mothers and community stakeholders regarding messages and channels of message dissemination. By using PAR, a learner engagement approach, the researchers intend to increase the likelihood that the CHMs are culturally appropriate and relevant to specific populations. The CHM-PAR model visually illustrates an interactive, iterative process of health message generation and testing. The paper concludes with implications for future research and outreach in a technological landscape where dissemination channels are dynamic. This paper provides a model for researchers and health educators to co-create messages in a desired format (e.g., length, voice, level of empathy, tone) preferred by their audiences and to examine dissemination methods that will best reach those audiences.

Mark 4A antenna control system data handling architecture study

NASA Technical Reports Server (NTRS)

Briggs, H. C.; Eldred, D. B.

1991-01-01

A high-level review was conducted to provide an analysis of the existing architecture used to handle data and implement control algorithms for NASA's Deep Space Network (DSN) antennas and to make system-level recommendations for improving this architecture so that the DSN antennas can support the ever-tightening requirements of the next decade and beyond. It was found that the existing system is seriously overloaded, with processor utilization approaching 100 percent. A number of factors contribute to this overloading, including dated hardware, inefficient software, and a message-passing strategy that depends on serial connections between machines. At the same time, the system has shortcomings and idiosyncrasies that require extensive human intervention. A custom operating system kernel and an obscure programming language exacerbate the problems and should be modernized. A new architecture is presented that addresses these and other issues. Key features of the new architecture include a simplified message passing hierarchy that utilizes a high-speed local area network, redesign of particular processing function algorithms, consolidation of functions, and implementation of the architecture in modern hardware and software using mainstream computer languages and operating systems. The system would also allow incremental hardware improvements as better and faster hardware for such systems becomes available, and costs could potentially be low enough that redundancy would be provided economically. Such a system could support DSN requirements for the foreseeable future, though thorough consideration must be given to hard computational requirements, porting existing software functionality to the new system, and issues of fault tolerance and recovery.

Task-parallel message passing interface implementation of Autodock4 for docking of very large databases of compounds using high-performance super-computers.

PubMed

Collignon, Barbara; Schulz, Roland; Smith, Jeremy C; Baudry, Jerome

2011-04-30

A message passing interface (MPI)-based implementation (Autodock4.lga.MPI) of the grid-based docking program Autodock4 has been developed to allow simultaneous and independent docking of multiple compounds on up to thousands of central processing units (CPUs) using the Lamarkian genetic algorithm. The MPI version reads a single binary file containing precalculated grids that represent the protein-ligand interactions, i.e., van der Waals, electrostatic, and desolvation potentials, and needs only two input parameter files for the entire docking run. In comparison, the serial version of Autodock4 reads ASCII grid files and requires one parameter file per compound. The modifications performed result in significantly reduced input/output activity compared with the serial version. Autodock4.lga.MPI scales up to 8192 CPUs with a maximal overhead of 16.3%, of which two thirds is due to input/output operations and one third originates from MPI operations. The optimal docking strategy, which minimizes docking CPU time without lowering the quality of the database enrichments, comprises the docking of ligands preordered from the most to the least flexible and the assignment of the number of energy evaluations as a function of the number of rotatable bounds. In 24 h, on 8192 high-performance computing CPUs, the present MPI version would allow docking to a rigid protein of about 300K small flexible compounds or 11 million rigid compounds.

A cryptographic hash function based on chaotic network automata

NASA Astrophysics Data System (ADS)

Machicao, Jeaneth; Bruno, Odemir M.

2017-12-01

Chaos theory has been used to develop several cryptographic methods relying on the pseudo-random properties extracted from simple nonlinear systems such as cellular automata (CA). Cryptographic hash functions (CHF) are commonly used to check data integrity. CHF “compress” arbitrary long messages (input) into much smaller representations called hash values or message digest (output), designed to prevent the ability to reverse the hash values into the original message. This paper proposes a chaos-based CHF inspired on an encryption method based on chaotic CA rule B1357-S2468. Here, we propose an hybrid model that combines CA and networks, called network automata (CNA), whose chaotic spatio-temporal outputs are used to compute a hash value. Following the Merkle and Damgård model of construction, a portion of the message is entered as the initial condition of the network automata, so that the rest parts of messages are iteratively entered to perturb the system. The chaotic network automata shuffles the message using flexible control parameters, so that the generated hash value is highly sensitive to the message. As demonstrated in our experiments, the proposed model has excellent pseudo-randomness and sensitivity properties with acceptable performance when compared to conventional hash functions.

How lay people respond to messages about genetics, health, and race.

PubMed

Condit, C; Bates, B

2005-08-01

There is a growing movement in medical genetics to develop, implement, and promote a model of race-based medicine. Although race-based medicine may become a widely disseminated standard of care, messages that advocate race-based selection for diagnosing, screening and prescribing drugs may exacerbate health disparities. These messages are present in clinical genetic counseling sessions, mass media, and everyday talk. Messages promoting linkages among genes, race, and health and messages emphasizing genetic causation may promote both general racism and genetically based racism. This mini-review examines research in three areas: studies that address the effects of these messages about genetics on levels of genetic determinism and genetic discrimination; studies that address the effects of these messages on attitudes about race; and, studies of the impacts of race-specific genetic messages on recipients. Following an integration of this research, this mini-review suggests that the current literature appears fragmented because of methodological and measurement issues and offers strategies for future research. Finally, the authors offer a path model to help organize future research examining the effects of messages about genetics on socioculturally based racism, genetically based racism, and unaccounted for racism. Research in this area is needed to understand and mitigate the negative attitudinal effects of messages that link genes, race, and health and/or emphasize genetic causation.

Evaluation of smoking prevention television messages based on the elaboration likelihood model

PubMed Central

Flynn, Brian S.; Worden, John K.; Bunn, Janice Yanushka; Connolly, Scott W.; Dorwaldt, Anne L.

2011-01-01

Progress in reducing youth smoking may depend on developing improved methods to communicate with higher risk youth. This study explored the potential of smoking prevention messages based on the Elaboration Likelihood Model (ELM) to address these needs. Structured evaluations of 12 smoking prevention messages based on three strategies derived from the ELM were conducted in classroom settings among a diverse sample of non-smoking middle school students in three states (n = 1771). Students categorized as likely to have higher involvement in a decision to initiate cigarette smoking reported relatively high ratings on a cognitive processing indicator for messages focused on factual arguments about negative consequences of smoking than for messages with fewer or no direct arguments. Message appeal ratings did not show greater preference for this message type among higher involved versus lower involved students. Ratings from students reporting lower academic achievement suggested difficulty processing factual information presented in these messages. The ELM may provide a useful strategy for reaching adolescents at risk for smoking initiation, but particular attention should be focused on lower academic achievers to ensure that messages are appropriate for them. This approach should be explored further before similar strategies could be recommended for large-scale implementation. PMID:21885672

Evaluation of smoking prevention television messages based on the elaboration likelihood model.

PubMed

Flynn, Brian S; Worden, John K; Bunn, Janice Yanushka; Connolly, Scott W; Dorwaldt, Anne L

2011-12-01

Progress in reducing youth smoking may depend on developing improved methods to communicate with higher risk youth. This study explored the potential of smoking prevention messages based on the Elaboration Likelihood Model (ELM) to address these needs. Structured evaluations of 12 smoking prevention messages based on three strategies derived from the ELM were conducted in classroom settings among a diverse sample of non-smoking middle school students in three states (n = 1771). Students categorized as likely to have higher involvement in a decision to initiate cigarette smoking reported relatively high ratings on a cognitive processing indicator for messages focused on factual arguments about negative consequences of smoking than for messages with fewer or no direct arguments. Message appeal ratings did not show greater preference for this message type among higher involved versus lower involved students. Ratings from students reporting lower academic achievement suggested difficulty processing factual information presented in these messages. The ELM may provide a useful strategy for reaching adolescents at risk for smoking initiation, but particular attention should be focused on lower academic achievers to ensure that messages are appropriate for them. This approach should be explored further before similar strategies could be recommended for large-scale implementation.

Social media for message testing: a multilevel approach to linking favorable viewer responses with message, producer, and viewer influence on YouTube.

PubMed

Paek, Hye-Jin; Hove, Thomas; Jeon, Jehoon

2013-01-01

To explore the feasibility of social media for message testing, this study connects favorable viewer responses to antismoking videos on YouTube with the videos' message characteristics (message sensation value [MSV] and appeals), producer types, and viewer influences (viewer rating and number of viewers). Through multilevel modeling, a content analysis of 7,561 viewer comments on antismoking videos is linked with a content analysis of 87 antismoking videos. Based on a cognitive response approach, viewer comments are classified and coded as message-oriented thought, video feature-relevant thought, and audience-generated thought. The three mixed logit models indicate that videos with a greater number of viewers consistently increased the odds of favorable viewer responses, while those presenting humor appeals decreased the odds of favorable message-oriented and audience-generated thoughts. Some significant interaction effects show that videos produced by laypeople may hinder favorable viewer responses, while a greater number of viewer comments can work jointly with videos presenting threat appeals to predict favorable viewer responses. Also, for a more accurate understanding of audience responses to the messages, nuance cues should be considered together with message features and viewer influences.

Toward Predicting Popularity of Social Marketing Messages

NASA Astrophysics Data System (ADS)

Yu, Bei; Chen, Miao; Kwok, Linchi

Popularity of social marketing messages indicates the effectiveness of the corresponding marketing strategies. This research aims to discover the characteristics of social marketing messages that contribute to different level of popularity. Using messages posted by a sample of restaurants on Facebook as a case study, we measured the message popularity by the number of "likes" voted by fans, and examined the relationship between the message popularity and two properties of the messages: (1) content, and (2) media type. Combining a number of text mining and statistics methods, we have discovered some interesting patterns correlated to "more popular" and "less popular" social marketing messages. This work lays foundation for building computational models to predict the popularity of social marketing messages in the future.

Rapid Growth in Surgeons’ Use of Secure Messaging in a Patient Portal

PubMed Central

Shenson, Jared A.; Cronin, Robert M.; Davis, Sharon E.; Chen, Qingxia; Jackson, Gretchen Purcell

2016-01-01

Background Use of secure messaging through patient portals has risen substantially in recent years due to provider incentives and consumer demand. Secure messaging may increase patient satisfaction and improve outcomes, but also adds to physician workload. Most prior studies of secure messaging focused on primary care and medical specialties. We examined surgeons’ use of secure messaging and the contribution of messaging to outpatient interactions in a broadly-deployed patient portal. Methods We determined the number of clinic visits and secure messages for surgical providers in the first three years (2008–10) after patient portal deployment at an academic medical center. We calculated the proportion of outpatient interaction conducted through messaging for each specialty. Logistic regression models compared the likelihood of message-based versus clinic outpatient interaction across surgical specialties. Results Over the study period, surgical providers delivered care in 648,200 clinic visits and received 83,912 messages, with more than 200% growth in monthly message volume. Surgical specialties receiving the most messages were orthopedics/podiatry (25.1%), otolaryngology (20.1%), urology (10.8%), and general surgery (9.6%); vascular surgery (0.8%) and pediatric general surgery (0.2%) received the fewest. The proportion of outpatient interactions conducted through secure messaging increased significantly from 5.4% in 2008 to 15.3% in 2010 (p<0.001) with all specialties experiencing growth. Heart/lung transplantation (74.9%), liver/kidney/pancreas transplantation (69.5%), and general surgery (48.7%) had the highest proportion of message-based outpatient interaction by the end of the study. Conclusions This study demonstrates rapid adoption of online secure messaging across surgical specialties with significant growth in its use for outpatient interaction. Some specialties, particularly those with long-term follow-up, interacted with patients more through secure messaging than in person. As surgeons devote more time to secure messaging, additional research will be needed to understand the care delivered through online interactions and to develop models for reimbursement. PMID:26123340

Effects of Motivational and Volitional Email Messages (MVEM) with Personal Messages on Undergraduate Students' Motivation, Study Habits and Achievement

ERIC Educational Resources Information Center

Kim, ChanMin; Keller, John M.

2008-01-01

This study investigated what kind of supportive information can be effective in improving the situation where there were severe motivational challenges. Motivational and volitional email messages (MVEM) were constructed based on an integrated model of four theories and methods, which are Keller's ARCS model, Kuhl's action control theory,…

A Biopsychological Model of Anti-drug PSA Processing: Developing Effective Persuasive Messages.

PubMed

Hohman, Zachary P; Keene, Justin Robert; Harris, Breanna N; Niedbala, Elizabeth M; Berke, Collin K

2017-11-01

For the current study, we developed and tested a biopsychological model to combine research on psychological tension, the Limited Capacity Model of Motivated Mediated Message Processing, and the endocrine system to predict and understand how people process anti-drug PSAs. We predicted that co-presentation of pleasant and unpleasant information, vs. solely pleasant or unpleasant, will trigger evaluative tension about the target behavior in persuasive messages and result in a biological response (increase in cortisol, alpha amylase, and heart rate). In experiment 1, we assessed the impact of co-presentation of pleasant and unpleasant information in persuasive messages on evaluative tension (conceptualized as attitude ambivalence), in experiment 2, we explored the impact of co-presentation on endocrine system responses (salivary cortisol and alpha amylase), and in experiment 3, we assessed the impact of co-presentation on heart rate. Across all experiments, we demonstrated that co-presentation of pleasant and unpleasant information, vs. solely pleasant or unpleasant, in persuasive communications leads to increases in attitude ambivalence, salivary cortisol, salivary alpha amylase, and heart rate. Taken together, the results support the initial paths of our biopsychological model of persuasive message processing and indicate that including both pleasant and unpleasant information in a message impacts the viewer. We predict that increases in evaluative tension and biological responses will aid in memory and cognitive processing of the message. However, future research is needed to test that hypothesis.

An Evaluation of Two Methods for Generating Synthetic HL7 Segments Reflecting Real-World Health Information Exchange Transactions

PubMed Central

Mwogi, Thomas S.; Biondich, Paul G.; Grannis, Shaun J.

2014-01-01

Motivated by the need for readily available data for testing an open-source health information exchange platform, we developed and evaluated two methods for generating synthetic messages. The methods used HL7 version 2 messages obtained from the Indiana Network for Patient Care. Data from both methods were analyzed to assess how effectively the output reflected original ‘real-world’ data. The Markov Chain method (MCM) used an algorithm based on transitional probability matrix while the Music Box model (MBM) randomly selected messages of particular trigger type from the original data to generate new messages. The MBM was faster, generated shorter messages and exhibited less variation in message length. The MCM required more computational power, generated longer messages with more message length variability. Both methods exhibited adequate coverage, producing a high proportion of messages consistent with original messages. Both methods yielded similar rates of valid messages. PMID:25954458

The message development tool: a case for effective operationalization of messaging in social marketing practice.

PubMed

Mattson, Marifran; Basu, Ambar

2010-07-01

That messages are essential, if not the most critical component of any communicative process, seems like an obvious claim. More so when the communication is about health--one of the most vital and elemental of human experiences (Babrow & Mattson, 2003). Any communication campaign that aims to change a target audience's health behaviors needs to centralize messages. Even though messaging strategies are an essential component of social marketing and are a widely used campaign model, health campaigns based on this framework have not always been able to effectively operationalize this key component, leading to cases where initiating and sustaining prescribed health behavior has been difficult (MacStravic, 2000). Based on an examination of the VERB campaign and an Australian breastfeeding promotion campaign, we propose a message development tool within the ambit of the social marketing framework that aims to extend the framework and ensure that the messaging component of the model is contextualized at the core of planning, implementation, and evaluation efforts.

ng: What next-generation languages can teach us about HENP frameworks in the manycore era

NASA Astrophysics Data System (ADS)

Binet, Sébastien

2011-12-01

Current High Energy and Nuclear Physics (HENP) frameworks were written before multicore systems became widely deployed. A 'single-thread' execution model naturally emerged from that environment, however, this no longer fits into the processing model on the dawn of the manycore era. Although previous work focused on minimizing the changes to be applied to the LHC frameworks (because of the data taking phase) while still trying to reap the benefits of the parallel-enhanced CPU architectures, this paper explores what new languages could bring to the design of the next-generation frameworks. Parallel programming is still in an intensive phase of R&D and no silver bullet exists despite the 30+ years of literature on the subject. Yet, several parallel programming styles have emerged: actors, message passing, communicating sequential processes, task-based programming, data flow programming, ... to name a few. We present the work of the prototyping of a next-generation framework in new and expressive languages (python and Go) to investigate how code clarity and robustness are affected and what are the downsides of using languages younger than FORTRAN/C/C++.

Network Inference via the Time-Varying Graphical Lasso

PubMed Central

Hallac, David; Park, Youngsuk; Boyd, Stephen; Leskovec, Jure

2018-01-01

Many important problems can be modeled as a system of interconnected entities, where each entity is recording time-dependent observations or measurements. In order to spot trends, detect anomalies, and interpret the temporal dynamics of such data, it is essential to understand the relationships between the different entities and how these relationships evolve over time. In this paper, we introduce the time-varying graphical lasso (TVGL), a method of inferring time-varying networks from raw time series data. We cast the problem in terms of estimating a sparse time-varying inverse covariance matrix, which reveals a dynamic network of interdependencies between the entities. Since dynamic network inference is a computationally expensive task, we derive a scalable message-passing algorithm based on the Alternating Direction Method of Multipliers (ADMM) to solve this problem in an efficient way. We also discuss several extensions, including a streaming algorithm to update the model and incorporate new observations in real time. Finally, we evaluate our TVGL algorithm on both real and synthetic datasets, obtaining interpretable results and outperforming state-of-the-art baselines in terms of both accuracy and scalability. PMID:29770256

Analysis of a parallelized nonlinear elliptic boundary value problem solver with application to reacting flows

NASA Technical Reports Server (NTRS)

Keyes, David E.; Smooke, Mitchell D.

1987-01-01

A parallelized finite difference code based on the Newton method for systems of nonlinear elliptic boundary value problems in two dimensions is analyzed in terms of computational complexity and parallel efficiency. An approximate cost function depending on 15 dimensionless parameters is derived for algorithms based on stripwise and boxwise decompositions of the domain and a one-to-one assignment of the strip or box subdomains to processors. The sensitivity of the cost functions to the parameters is explored in regions of parameter space corresponding to model small-order systems with inexpensive function evaluations and also a coupled system of nineteen equations with very expensive function evaluations. The algorithm was implemented on the Intel Hypercube, and some experimental results for the model problems with stripwise decompositions are presented and compared with the theory. In the context of computational combustion problems, multiprocessors of either message-passing or shared-memory type may be employed with stripwise decompositions to realize speedup of O(n), where n is mesh resolution in one direction, for reasonable n.

Optimizing NEURON Simulation Environment Using Remote Memory Access with Recursive Doubling on Distributed Memory Systems.

PubMed

Shehzad, Danish; Bozkuş, Zeki

2016-01-01

Increase in complexity of neuronal network models escalated the efforts to make NEURON simulation environment efficient. The computational neuroscientists divided the equations into subnets amongst multiple processors for achieving better hardware performance. On parallel machines for neuronal networks, interprocessor spikes exchange consumes large section of overall simulation time. In NEURON for communication between processors Message Passing Interface (MPI) is used. MPI_Allgather collective is exercised for spikes exchange after each interval across distributed memory systems. The increase in number of processors though results in achieving concurrency and better performance but it inversely affects MPI_Allgather which increases communication time between processors. This necessitates improving communication methodology to decrease the spikes exchange time over distributed memory systems. This work has improved MPI_Allgather method using Remote Memory Access (RMA) by moving two-sided communication to one-sided communication, and use of recursive doubling mechanism facilitates achieving efficient communication between the processors in precise steps. This approach enhanced communication concurrency and has improved overall runtime making NEURON more efficient for simulation of large neuronal network models.

Optimizing NEURON Simulation Environment Using Remote Memory Access with Recursive Doubling on Distributed Memory Systems

PubMed Central

Bozkuş, Zeki

2016-01-01

Increase in complexity of neuronal network models escalated the efforts to make NEURON simulation environment efficient. The computational neuroscientists divided the equations into subnets amongst multiple processors for achieving better hardware performance. On parallel machines for neuronal networks, interprocessor spikes exchange consumes large section of overall simulation time. In NEURON for communication between processors Message Passing Interface (MPI) is used. MPI_Allgather collective is exercised for spikes exchange after each interval across distributed memory systems. The increase in number of processors though results in achieving concurrency and better performance but it inversely affects MPI_Allgather which increases communication time between processors. This necessitates improving communication methodology to decrease the spikes exchange time over distributed memory systems. This work has improved MPI_Allgather method using Remote Memory Access (RMA) by moving two-sided communication to one-sided communication, and use of recursive doubling mechanism facilitates achieving efficient communication between the processors in precise steps. This approach enhanced communication concurrency and has improved overall runtime making NEURON more efficient for simulation of large neuronal network models. PMID:27413363

PRATHAM: Parallel Thermal Hydraulics Simulations using Advanced Mesoscopic Methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joshi, Abhijit S; Jain, Prashant K; Mudrich, Jaime A

2012-01-01

At the Oak Ridge National Laboratory, efforts are under way to develop a 3D, parallel LBM code called PRATHAM (PaRAllel Thermal Hydraulic simulations using Advanced Mesoscopic Methods) to demonstrate the accuracy and scalability of LBM for turbulent flow simulations in nuclear applications. The code has been developed using FORTRAN-90, and parallelized using the message passing interface MPI library. Silo library is used to compact and write the data files, and VisIt visualization software is used to post-process the simulation data in parallel. Both the single relaxation time (SRT) and multi relaxation time (MRT) LBM schemes have been implemented in PRATHAM.more » To capture turbulence without prohibitively increasing the grid resolution requirements, an LES approach [5] is adopted allowing large scale eddies to be numerically resolved while modeling the smaller (subgrid) eddies. In this work, a Smagorinsky model has been used, which modifies the fluid viscosity by an additional eddy viscosity depending on the magnitude of the rate-of-strain tensor. In LBM, this is achieved by locally varying the relaxation time of the fluid.« less

GEOS Atmospheric Model: Challenges at Exascale

NASA Technical Reports Server (NTRS)

Putman, William M.; Suarez, Max J.

2017-01-01

The Goddard Earth Observing System (GEOS) model at NASA's Global Modeling and Assimilation Office (GMAO) is used to simulate the multi-scale variability of the Earth's weather and climate, and is used primarily to assimilate conventional and satellite-based observations for weather forecasting and reanalysis. In addition, assimilations coupled to an ocean model are used for longer-term forecasting (e.g., El Nino) on seasonal to interannual times-scales. The GMAO's research activities, including system development, focus on numerous time and space scales, as detailed on the GMAO website, where they are tabbed under five major themes: Weather Analysis and Prediction; Seasonal-Decadal Analysis and Prediction; Reanalysis; Global Mesoscale Modeling, and Observing System Science. A brief description of the GEOS systems can also be found at the GMAO website. GEOS executes as a collection of earth system components connected through the Earth System Modeling Framework (ESMF). The ESMF layer is supplemented with the MAPL (Modeling, Analysis, and Prediction Layer) software toolkit developed at the GMAO, which facilitates the organization of the computational components into a hierarchical architecture. GEOS systems run in parallel using a horizontal decomposition of the Earth's sphere into processing elements (PEs). Communication between PEs is primarily through a message passing framework, using the message passing interface (MPI), and through explicit use of node-level shared memory access via the SHMEM (Symmetric Hierarchical Memory access) protocol. Production GEOS weather prediction systems currently run at 12.5-kilometer horizontal resolution with 72 vertical levels decomposed into PEs associated with 5,400 MPI processes. Research GEOS systems run at resolutions as fine as 1.5 kilometers globally using as many as 30,000 MPI processes. Looking forward, these systems can be expected to see a 2 times increase in horizontal resolution every two to three years, as well as less frequent increases in vertical resolution. Coupling these resolution changes with increases in complexity, the computational demands on the GEOS production and research systems should easily increase 100-fold over the next five years. Currently, our 12.5 kilometer weather prediction system narrowly meets the time-to-solution demands of a near-real-time production system. Work is now in progress to take advantage of a hybrid MPI-OpenMP parallelism strategy, in an attempt to achieve a modest two-fold speed-up to accommodate an immediate demand due to increased scientific complexity and an increase in vertical resolution. Pursuing demands that require a 10- to 100-fold increases or more, however, would require a detailed exploration of the computational profile of GEOS, as well as targeted solutions using more advanced high-performance computing technologies. Increased computing demands of 100-fold will be required within five years based on anticipated changes in the GEOS production systems, increases of 1000-fold can be anticipated over the next ten years.

A new deadlock resolution protocol and message matching algorithm for the extreme-scale simulator

DOE PAGES

Engelmann, Christian; Naughton, III, Thomas J.

2016-03-22

Investigating the performance of parallel applications at scale on future high-performance computing (HPC) architectures and the performance impact of different HPC architecture choices is an important component of HPC hardware/software co-design. The Extreme-scale Simulator (xSim) is a simulation toolkit for investigating the performance of parallel applications at scale. xSim scales to millions of simulated Message Passing Interface (MPI) processes. The overhead introduced by a simulation tool is an important performance and productivity aspect. This paper documents two improvements to xSim: (1)~a new deadlock resolution protocol to reduce the parallel discrete event simulation overhead and (2)~a new simulated MPI message matchingmore » algorithm to reduce the oversubscription management overhead. The results clearly show a significant performance improvement. The simulation overhead for running the NAS Parallel Benchmark suite was reduced from 102% to 0% for the embarrassingly parallel (EP) benchmark and from 1,020% to 238% for the conjugate gradient (CG) benchmark. xSim offers a highly accurate simulation mode for better tracking of injected MPI process failures. Furthermore, with highly accurate simulation, the overhead was reduced from 3,332% to 204% for EP and from 37,511% to 13,808% for CG.« less

CDC MessageWorks: Designing and Validating a Social Marketing Tool to Craft and Defend Effective Messages.

PubMed

Cole, Galen E; Keller, Punam A; Reynolds, Jennifer; Schaur, Michelle; Krause, Diane

2016-03-01

The Centers for Disease Control and Prevention's Division of Cancer Prevention and Control, in partnership with Oak Ridge Associated Universities, designed an online social marketing strategy tool, MessageWorks, to help health communicators effectively formulate messages aimed at changing health behaviors and evaluate message tactics and audience characteristics. MessageWorks is based on the advisor for risk communication model that identifies 10 variables that can be used to predict target audience intentions to comply with health recommendations. This article discusses the value of the MessageWorks tool to health communicators and to the field of social marketing by (1) describing the scientific evidence supporting use of MessageWorks to improve health communication practice and (2) summarizing how to use MessageWorks and interpret the results it produces.

Students' Silent Messages: Can Teacher Verbal and Nonverbal Immediacy Moderate Student Use of Text Messaging in Class?

ERIC Educational Resources Information Center

Wei, Fang-Yi Flora; Wang, Y. Ken

2010-01-01

This study investigated the relationship between teacher immediacy and college students' use of text messaging in class. Using a cross-sectional survey sample (N=228), structural equation model analyses showed that students' learning motivation does not mediate the potential effects of teacher immediacy and students' use of text messaging in…

Communication theory and the search for effective feedback.

PubMed

Simonds, S K

1995-01-01

If messages transmitted to the public, patients and health professionals could be assured of being received, understood and acted on as intended by the senders of messages, there would be little need to focus on communications and feedback. That the physician's office, the healthcare system and the community are littered with messages that 'never got through' attests to the problem of ineffective communications and the absence of effective feedback. Communication theorists, health psychologists and thoughtful health professionals, particularly those working in community hypertension programmes, have developed approaches that improve the probabilities of 'getting the message through'. Theory-based communications with built-in feedback and 'feed-forward' enhance the probabilities of success considerably. This presentation explores these problems using the SMCR model of communication. Differences between linear models and transactional models are discussed. On the assumption that the health message environments of the future will be increasingly complex with highly differentiated target audiences in a rapid paced computer and electronically driven world, 'getting the message through' will become an even greater challenge than in the recent past. Specific steps to change communication approaches in this setting are proposed.

Application Portable Parallel Library

NASA Technical Reports Server (NTRS)

Cole, Gary L.; Blech, Richard A.; Quealy, Angela; Townsend, Scott

1995-01-01

Application Portable Parallel Library (APPL) computer program is subroutine-based message-passing software library intended to provide consistent interface to variety of multiprocessor computers on market today. Minimizes effort needed to move application program from one computer to another. User develops application program once and then easily moves application program from parallel computer on which created to another parallel computer. ("Parallel computer" also include heterogeneous collection of networked computers). Written in C language with one FORTRAN 77 subroutine for UNIX-based computers and callable from application programs written in C language or FORTRAN 77.

Design and evaluation of Nemesis, a scalable, low-latency, message-passing communication subsystem.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buntinas, D.; Mercier, G.; Gropp, W.

2005-12-02

This paper presents a new low-level communication subsystem called Nemesis. Nemesis has been designed and implemented to be scalable and efficient both in the intranode communication context using shared-memory and in the internode communication case using high-performance networks and is natively multimethod-enabled. Nemesis has been integrated in MPICH2 as a CH3 channel and delivers better performance than other dedicated communication channels in MPICH2. Furthermore, the resulting MPICH2 architecture outperforms other MPI implementations in point-to-point benchmarks.

Leading article: Use of smartphones to pass on information about patients - what are the current issues?

PubMed

Rokadiya, S; McCaul, J A; Mitchell, D A; Brennan, P A

2016-07-01

Many doctors now use mobile devices such as smartphones to communicate with one another about their patients, and sometimes this is without the knowledge and approval of their employer. We know of little information about the use of texting and other web-based messaging services by doctors in hospitals, so we reviewed relevant published studies to assess the safety and usefulness of current methods of digital communication. Copyright © 2016 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Implementation of a 3D mixing layer code on parallel computers

NASA Technical Reports Server (NTRS)

Roe, K.; Thakur, R.; Dang, T.; Bogucz, E.

1995-01-01

This paper summarizes our progress and experience in the development of a Computational-Fluid-Dynamics code on parallel computers to simulate three-dimensional spatially-developing mixing layers. In this initial study, the three-dimensional time-dependent Euler equations are solved using a finite-volume explicit time-marching algorithm. The code was first programmed in Fortran 77 for sequential computers. The code was then converted for use on parallel computers using the conventional message-passing technique, while we have not been able to compile the code with the present version of HPF compilers.

Multiple-Ring Digital Communication Network

NASA Technical Reports Server (NTRS)

Kirkham, Harold

1992-01-01

Optical-fiber digital communication network to support data-acquisition and control functions of electric-power-distribution networks. Optical-fiber links of communication network follow power-distribution routes. Since fiber crosses open power switches, communication network includes multiple interconnected loops with occasional spurs. At each intersection node is needed. Nodes of communication network include power-distribution substations and power-controlling units. In addition to serving data acquisition and control functions, each node acts as repeater, passing on messages to next node(s). Multiple-ring communication network operates on new AbNET protocol and features fiber-optic communication.

Addressing the challenges of standalone multi-core simulations in molecular dynamics

NASA Astrophysics Data System (ADS)

Ocaya, R. O.; Terblans, J. J.

2017-07-01

Computational modelling in material science involves mathematical abstractions of force fields between particles with the aim to postulate, develop and understand materials by simulation. The aggregated pairwise interactions of the material's particles lead to a deduction of its macroscopic behaviours. For practically meaningful macroscopic scales, a large amount of data are generated, leading to vast execution times. Simulation times of hours, days or weeks for moderately sized problems are not uncommon. The reduction of simulation times, improved result accuracy and the associated software and hardware engineering challenges are the main motivations for many of the ongoing researches in the computational sciences. This contribution is concerned mainly with simulations that can be done on a "standalone" computer based on Message Passing Interfaces (MPI), parallel code running on hardware platforms with wide specifications, such as single/multi- processor, multi-core machines with minimal reconfiguration for upward scaling of computational power. The widely available, documented and standardized MPI library provides this functionality through the MPI_Comm_size (), MPI_Comm_rank () and MPI_Reduce () functions. A survey of the literature shows that relatively little is written with respect to the efficient extraction of the inherent computational power in a cluster. In this work, we discuss the main avenues available to tap into this extra power without compromising computational accuracy. We also present methods to overcome the high inertia encountered in single-node-based computational molecular dynamics. We begin by surveying the current state of the art and discuss what it takes to achieve parallelism, efficiency and enhanced computational accuracy through program threads and message passing interfaces. Several code illustrations are given. The pros and cons of writing raw code as opposed to using heuristic, third-party code are also discussed. The growing trend towards graphical processor units and virtual computing clouds for high-performance computing is also discussed. Finally, we present the comparative results of vacancy formation energy calculations using our own parallelized standalone code called Verlet-Stormer velocity (VSV) operating on 30,000 copper atoms. The code is based on the Sutton-Chen implementation of the Finnis-Sinclair pairwise embedded atom potential. A link to the code is also given.

Probabilistic Priority Message Checking Modeling Based on Controller Area Networks

NASA Astrophysics Data System (ADS)

Lin, Cheng-Min

Although the probabilistic model checking tool called PRISM has been applied in many communication systems, such as wireless local area network, Bluetooth, and ZigBee, the technique is not used in a controller area network (CAN). In this paper, we use PRISM to model the mechanism of priority messages for CAN because the mechanism has allowed CAN to become the leader in serial communication for automobile and industry control. Through modeling CAN, it is easy to analyze the characteristic of CAN for further improving the security and efficiency of automobiles. The Markov chain model helps us to model the behaviour of priority messages.

Accelerating Climate and Weather Simulations through Hybrid Computing

NASA Technical Reports Server (NTRS)

Zhou, Shujia; Cruz, Carlos; Duffy, Daniel; Tucker, Robert; Purcell, Mark

2011-01-01

Unconventional multi- and many-core processors (e.g. IBM (R) Cell B.E.(TM) and NVIDIA (R) GPU) have emerged as effective accelerators in trial climate and weather simulations. Yet these climate and weather models typically run on parallel computers with conventional processors (e.g. Intel, AMD, and IBM) using Message Passing Interface. To address challenges involved in efficiently and easily connecting accelerators to parallel computers, we investigated using IBM's Dynamic Application Virtualization (TM) (IBM DAV) software in a prototype hybrid computing system with representative climate and weather model components. The hybrid system comprises two Intel blades and two IBM QS22 Cell B.E. blades, connected with both InfiniBand(R) (IB) and 1-Gigabit Ethernet. The system significantly accelerates a solar radiation model component by offloading compute-intensive calculations to the Cell blades. Systematic tests show that IBM DAV can seamlessly offload compute-intensive calculations from Intel blades to Cell B.E. blades in a scalable, load-balanced manner. However, noticeable communication overhead was observed, mainly due to IP over the IB protocol. Full utilization of IB Sockets Direct Protocol and the lower latency production version of IBM DAV will reduce this overhead.

LEGION: Lightweight Expandable Group of Independently Operating Nodes

NASA Technical Reports Server (NTRS)

Burl, Michael C.

2012-01-01

LEGION is a lightweight C-language software library that enables distributed asynchronous data processing with a loosely coupled set of compute nodes. Loosely coupled means that a node can offer itself in service to a larger task at any time and can withdraw itself from service at any time, provided it is not actively engaged in an assignment. The main program, i.e., the one attempting to solve the larger task, does not need to know up front which nodes will be available, how many nodes will be available, or at what times the nodes will be available, which is normally the case in a "volunteer computing" framework. The LEGION software accomplishes its goals by providing message-based, inter-process communication similar to MPI (message passing interface), but without the tight coupling requirements. The software is lightweight and easy to install as it is written in standard C with no exotic library dependencies. LEGION has been demonstrated in a challenging planetary science application in which a machine learning system is used in closed-loop fashion to efficiently explore the input parameter space of a complex numerical simulation. The machine learning system decides which jobs to run through the simulator; then, through LEGION calls, the system farms those jobs out to a collection of compute nodes, retrieves the job results as they become available, and updates a predictive model of how the simulator maps inputs to outputs. The machine learning system decides which new set of jobs would be most informative to run given the results so far; this basic loop is repeated until sufficient insight into the physical system modeled by the simulator is obtained.

Racial/Ethnic Socialization and Identity Development in Black Families: The Role of Parent and Youth Reports

PubMed Central

Peck, Stephen C.; Brodish, Amanda B.; Malanchuk, Oksana; Banerjee, Meeta; Eccles, Jacquelynne S.

2014-01-01

Racial/ethnic (R/E) socialization is widely practiced in R/E minority families. However, only recently have models been developed to understand how parents’ R/E socialization messages influence adolescent development. The primary goal of the present study was to clarify and extend existing work on R/E socialization in African American (Black) families by distinguishing between parent and youth reports of parents’ R/E socialization messages and examining the extent to which adolescents and their parents agree about these socialization messages. In addition, we tested a theoretical model in which parent reported R/E socialization messages have an indirect effect on the development of youth R/E identity through youth reports of their parents’ R/E socialization messages. Using a combination of open- and close-ended data from a longitudinal study of self-identified Black adolescents and their parents, we found statistically significant parent-youth agreement about whether or not parents send both general R/E socialization messages and, for daughters, specific R/E socialization messages. R/E socialization messages focused on promoting cultural pride and history were associated positively with R/E identity development, whereas messages focused on preparing youth for discrimination tended to be unrelated to R/E identity development. The results largely supported the hypothesis that parent reports of parents’ R/E socialization messages are related indirectly to the development of adolescent R/E identity via youth reports of parents’ R/E socialization messages. PMID:24798504

A Theory-Based Video Messaging Mobile Phone Intervention for Smoking Cessation: Randomized Controlled Trial

PubMed Central

Dorey, Enid; Bramley, Dale; Bullen, Chris; Denny, Simon; Elley, C Raina; Maddison, Ralph; McRobbie, Hayden; Parag, Varsha; Rodgers, Anthony; Salmon, Penny

2011-01-01

Background Advances in technology allowed the development of a novel smoking cessation program delivered by video messages sent to mobile phones. This social cognitive theory-based intervention (called “STUB IT”) used observational learning via short video diary messages from role models going through the quitting process to teach behavioral change techniques. Objective The objective of our study was to assess the effectiveness of a multimedia mobile phone intervention for smoking cessation. Methods A randomized controlled trial was conducted with 6-month follow-up. Participants had to be 16 years of age or over, be current daily smokers, be ready to quit, and have a video message-capable phone. Recruitment targeted younger adults predominantly through radio and online advertising. Registration and data collection were completed online, prompted by text messages. The intervention group received an automated package of video and text messages over 6 months that was tailored to self-selected quit date, role model, and timing of messages. Extra messages were available on demand to beat cravings and address lapses. The control group also set a quit date and received a general health video message sent to their phone every 2 weeks. Results The target sample size was not achieved due to difficulty recruiting young adult quitters. Of the 226 randomized participants, 47% (107/226) were female and 24% (54/226) were Maori (indigenous population of New Zealand). Their mean age was 27 years (SD 8.7), and there was a high level of nicotine addiction. Continuous abstinence at 6 months was 26.4% (29/110) in the intervention group and 27.6% (32/116) in the control group (P = .8). Feedback from participants indicated that the support provided by the video role models was important and appreciated. Conclusions This study was not able to demonstrate a statistically significant effect of the complex video messaging mobile phone intervention compared with simple general health video messages via mobile phone. However, there was sufficient positive feedback about the ease of use of this novel intervention, and the support obtained by observing the role model video messages, to warrant further investigation. Trial registration Australian New Zealand Clinical Trials Registry Number: ACTRN12606000476538; http://www.anzctr.org.au/trial_view.aspx?ID=81688 (Archived by WebCite at http://www.webcitation.org/5umMU4sZi) PMID:21371991

A theory-based video messaging mobile phone intervention for smoking cessation: randomized controlled trial.

PubMed

Whittaker, Robyn; Dorey, Enid; Bramley, Dale; Bullen, Chris; Denny, Simon; Elley, C Raina; Maddison, Ralph; McRobbie, Hayden; Parag, Varsha; Rodgers, Anthony; Salmon, Penny

2011-01-21

Advances in technology allowed the development of a novel smoking cessation program delivered by video messages sent to mobile phones. This social cognitive theory-based intervention (called "STUB IT") used observational learning via short video diary messages from role models going through the quitting process to teach behavioral change techniques. The objective of our study was to assess the effectiveness of a multimedia mobile phone intervention for smoking cessation. A randomized controlled trial was conducted with 6-month follow-up. Participants had to be 16 years of age or over, be current daily smokers, be ready to quit, and have a video message-capable phone. Recruitment targeted younger adults predominantly through radio and online advertising. Registration and data collection were completed online, prompted by text messages. The intervention group received an automated package of video and text messages over 6 months that was tailored to self-selected quit date, role model, and timing of messages. Extra messages were available on demand to beat cravings and address lapses. The control group also set a quit date and received a general health video message sent to their phone every 2 weeks. The target sample size was not achieved due to difficulty recruiting young adult quitters. Of the 226 randomized participants, 47% (107/226) were female and 24% (54/226) were Maori (indigenous population of New Zealand). Their mean age was 27 years (SD 8.7), and there was a high level of nicotine addiction. Continuous abstinence at 6 months was 26.4% (29/110) in the intervention group and 27.6% (32/116) in the control group (P = .8). Feedback from participants indicated that the support provided by the video role models was important and appreciated. This study was not able to demonstrate a statistically significant effect of the complex video messaging mobile phone intervention compared with simple general health video messages via mobile phone. However, there was sufficient positive feedback about the ease of use of this novel intervention, and the support obtained by observing the role model video messages, to warrant further investigation. Australian New Zealand Clinical Trials Registry Number: ACTRN12606000476538; http://www.anzctr.org.au/trial_view.aspx?ID=81688 (Archived by WebCite at http://www.webcitation.org/5umMU4sZi).

Getting the Message? Native Reactive Electrophiles Pass Two Out of Three Thresholds to be Bona Fide Signaling Mediators.

PubMed

Poganik, Jesse R; Long, Marcus J C; Aye, Yimon

2018-05-01

Precision cell signaling activities of reactive electrophilic species (RES) are arguably among the most poorly-understood means to transmit biological messages. Latest research implicates native RES to be a chemically-distinct subset of endogenous redox signals that influence cell decision making through non-enzyme-assisted modifications of specific proteins. Yet, fundamental questions remain regarding the role of RES as bona fide second messengers. Here, we lay out three sets of criteria we feel need to be met for RES to be considered as true cellular signals that directly mediate information transfer by modifying "first-responding" sensor proteins. We critically assess the available evidence and define the extent to which each criterion has been fulfilled. Finally, we offer some ideas on the future trajectories of the electrophile signaling field taking inspiration from work that has been done to understand canonical signaling mediators. Also see the video abstract here: https://youtu.be/rG7o0clVP0c. © 2018 WILEY Periodicals, Inc.

CDC MessageWorks: Designing and Validating a Social Marketing Tool to Craft and Defend Effective Messages

PubMed Central

Cole, Galen E.; Keller, Punam A.; Reynolds, Jennifer; Schaur, Michelle; Krause, Diane

2016-01-01

The Centers for Disease Control and Prevention’s Division of Cancer Prevention and Control, in partnership with Oak Ridge Associated Universities, designed an online social marketing strategy tool, MessageWorks, to help health communicators effectively formulate messages aimed at changing health behaviors and evaluate message tactics and audience characteristics. MessageWorks is based on the advisor for risk communication model that identifies 10 variables that can be used to predict target audience intentions to comply with health recommendations. This article discusses the value of the MessageWorks tool to health communicators and to the field of social marketing by (1) describing the scientific evidence supporting use of MessageWorks to improve health communication practice and (2) summarizing how to use MessageWorks and interpret the results it produces. PMID:26877714

Messages about appearance, food, weight and exercise in "tween" television.

PubMed

Simpson, Courtney C; Kwitowski, Melissa; Boutte, Rachel; Gow, Rachel W; Mazzeo, Suzanne E

2016-12-01

Tweens (children ages ~8-14years) are a relatively recently defined age group, increasingly targeted by marketers. Individuals in this age group are particularly vulnerable to opinions and behaviors presented in media messages, given their level of cognitive and social development. However, little research has examined messages about appearance, food, weight, and exercise in television specifically targeting tweens, despite the popularity of this media type among this age group. This study used a content analytic approach to explore these messages in the five most popular television shows for tweens on the Disney Channel (as of 2015). Using a multiple-pass approach, relevant content in episodes from the most recently completed seasons of each show was coded. Appearance related incidents occurred in every episode; these most frequently mentioned attractiveness/beauty. Food related incidents were also present in every episode; typically, these situations were appearance and weight neutral. Exercise related incidents occurred in 53.3% of episodes; the majority expressed resistance to exercise. Weight related incidents occurred in 40.0% of the episodes; the majority praised the muscular ideal. Women were more likely to initiate appearance incidents, and men were more likely to initiate exercise incidents. These results suggest that programs specifically marketed to tweens reinforce appearance ideals, including stereotypes about female attractiveness and male athleticism, two constructs linked to eating pathology and body dissatisfaction. Given the developmental vulnerability of the target group, these findings are concerning, and highlight potential foci for prevention programming, including media literacy, for tweens. Copyright © 2016 Elsevier Ltd. All rights reserved.

In the Face of Cybersecurity: How the Common Information Model Can Be Used

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skare, Paul; Falk, Herbert; Rice, Mark

2016-01-01

Efforts are underway to combine smart grid information, devices, networking, and emergency response information to create messages that are not dependent on specific standards development organizations (SDOs). This supports a future-proof approach of allowing changes in the canonical data models (CDMs) going forward without having to perform forklift replacements of solutions that use the messages. This also allows end users (electric utilities) to upgrade individual components of a larger system while keeping the message payload definitions intact. The goal is to enable public and private information sharing securely in a standards-based approach that can be integrated into existing operations. Wemore » provide an example architecture that could benefit from this multi-SDO, secure message approach. This article also describes how to improve message security« less

Examining HPV threat-to-efficacy ratios in the Extended Parallel Process Model.

PubMed

Carcioppolo, Nick; Jensen, Jakob D; Wilson, Steven R; Collins, W Bart; Carrion, Melissa; Linnemeier, Georgiann

2013-01-01

The Extended Parallel Process Model (EPPM) posits that an effective fear appeal includes both threat and efficacy components; however, research has not addressed whether there is an optimal threat-to-efficacy ratio. It is possible that varying levels of threat and efficacy in a persuasive message could yield different effects on attitudes, beliefs, and behaviors. In a laboratory experiment, women (n = 442) were exposed to human papilloma virus (HPV) prevention messages containing one of six threat-to-efficacy ratios and one of two message frames (messages emphasizing the connection between HPV and cervical cancer or HPV and genital warts). Multiple mediation analysis revealed that a 1-to-1 ratio of threat to efficacy was most effective at increasing prevention intentions, primarily because it caused more fear and risk susceptibility than other message ratios. Response efficacy significantly mediated the relationship between message framing and intentions, such that participants exposed to a genital warts message reported significantly higher intentions, and this association can be explained in part through response efficacy. Implications for future theoretical research as well as campaigns and intervention research are discussed.

The persuasive power of oral health promotion messages: a theory of planned behavior approach to dental checkups among young adults.

PubMed

Anderson, Christina N; Noar, Seth M; Rogers, Brandi D

2013-01-01

Although routine dental checkups are important for both oral and overall health, several factors influence young adults' use or nonuse of dental services. The two studies included in this report tested the theory of reasoned action (TRA), the theory of planned behavior (TPB), and an expanded TPB model in predicting young adults' routine dental checkups. Additionally, the study tested the perceived message effectiveness of TPB-based messages. Results support the use of an expanded TPB model (particularly adding satisfaction with the dentist and environmental constraints to the traditional model) for an understanding of routine dental checkup intention and behavior, and, most notably, provide support for the use of subjective norm-based messages to prompt dental checkups. This study lays the groundwork for a health communication campaign encouraging routine dental checkups among young adults. The use of targeting and tailoring to design effective oral health media campaign messages is discussed.

Markov source model for printed music decoding

NASA Astrophysics Data System (ADS)

Kopec, Gary E.; Chou, Philip A.; Maltz, David A.

1995-03-01

This paper describes a Markov source model for a simple subset of printed music notation. The model is based on the Adobe Sonata music symbol set and a message language of our own design. Chord imaging is the most complex part of the model. Much of the complexity follows from a rule of music typography that requires the noteheads for adjacent pitches to be placed on opposite sides of the chord stem. This rule leads to a proliferation of cases for other typographic details such as dot placement. We describe the language of message strings accepted by the model and discuss some of the imaging issues associated with various aspects of the message language. We also point out some aspects of music notation that appear problematic for a finite-state representation. Development of the model was greatly facilitated by the duality between image synthesis and image decoding. Although our ultimate objective was a music image model for use in decoding, most of the development proceeded by using the evolving model for image synthesis, since it is computationally far less costly to image a message than to decode an image.

[Effects of attitude formation, persuasive message, and source expertise on attitude change: an examination based on the Elaboration Likelihood Model and the Attitude Formation Theory].

PubMed

Nakamura, M; Saito, K; Wakabayashi, M

1990-04-01

The purpose of this study was to investigate how attitude change is generated by the recipient's degree of attitude formation, evaluative-emotional elements contained in the persuasive messages, and source expertise as a peripheral cue in the persuasion context. Hypotheses based on the Attitude Formation Theory of Mizuhara (1982) and the Elaboration Likelihood Model of Petty and Cacioppo (1981, 1986) were examined. Eighty undergraduate students served as subjects in the experiment, the first stage of which involving manipulating the degree of attitude formation with respect to nuclear power development. Then, the experimenter presented persuasive messages with varying combinations of evaluative-emotional elements from a source with either high or low expertise on the subject. Results revealed a significant interaction effect on attitude change among attitude formation, persuasive message and the expertise of the message source. That is, high attitude formation subjects resisted evaluative-emotional persuasion from the high expertise source while low attitude formation subjects changed their attitude when exposed to the same persuasive message from a low expertise source. Results exceeded initial predictions based on the Attitude Formation Theory and the Elaboration Likelihood Model.

Porting marine ecosystem model spin-up using transport matrices to GPUs

NASA Astrophysics Data System (ADS)

Siewertsen, E.; Piwonski, J.; Slawig, T.

2013-01-01

We have ported an implementation of the spin-up for marine ecosystem models based on transport matrices to graphics processing units (GPUs). The original implementation was designed for distributed-memory architectures and uses the Portable, Extensible Toolkit for Scientific Computation (PETSc) library that is based on the Message Passing Interface (MPI) standard. The spin-up computes a steady seasonal cycle of ecosystem tracers with climatological ocean circulation data as forcing. Since the transport is linear with respect to the tracers, the resulting operator is represented by matrices. Each iteration of the spin-up involves two matrix-vector multiplications and the evaluation of the used biogeochemical model. The original code was written in C and Fortran. On the GPU, we use the Compute Unified Device Architecture (CUDA) standard, a customized version of PETSc and a commercial CUDA Fortran compiler. We describe the extensions to PETSc and the modifications of the original C and Fortran codes that had to be done. Here we make use of freely available libraries for the GPU. We analyze the computational effort of the main parts of the spin-up for two exemplar ecosystem models and compare the overall computational time to those necessary on different CPUs. The results show that a consumer GPU can compete with a significant number of cluster CPUs without further code optimization.

Evaluation of emotion-based messages designed to motivate Hispanic and Asian parents of early adolescents to engage in calcium-rich food and beverage parenting practices.

PubMed

Banna, Jinan Corinne; Reicks, Marla; Gunther, Carolyn; Richards, Rickelle; Bruhn, Christine; Cluskey, Mary; Wong, Siew Sun; Misner, Scottie; Hongu, Nobuko; Johnston, N Paul

2016-08-01

Setting healthful beverage expectations, making calcium-rich foods and beverages (CRF/B) available, and role modeling are parenting practices promoting calcium intake among early adolescents. This study aimed to evaluate emotion-based messages designed to motivate parents of early adolescents to perform these practices. Emotion-based messages were developed for each parenting practice and tested in 35 parents from 5 states. Findings were used to modify messages and develop a survey administered via Amazon MechanicalTurk to a convenience sample of Asian (n = 166) and Hispanic (n = 184) parents of children 10-13 years. Main outcome measures were message comprehension, motivation, relevance, acceptability, and novelty. Engagement in the parenting practices was also assessed. Message comprehension was acceptable for the majority of parents. Most also agreed that messages were motivational (setting healthful beverage expectations (69.0%), making CRF/B available (67.4%), and role modeling (80.0%)), relevant and acceptable. About 30-50% indicated they had not seen the information before. Many parents indicated they were already engaging in the practices (> 70%). No racial/ethnic differences were observed for responses to messages or engaging in parenting practices. Results indicate that emotion-based messages designed to motivate parents to engage in parenting practices that promote calcium intake among early adolescents were motivating, relevant, and acceptable.

Development of a distributed control system for TOTEM experiment using ASIO Boost C++ libraries

NASA Astrophysics Data System (ADS)

Cafagna, F.; Mercadante, A.; Minafra, N.; Quinto, M.; Radicioni, E.

2014-06-01

The main goals of the TOTEM Experiment at the LHC are the measurements of the elastic and total p-p cross sections and the studies of the diffractive dissociation processes. Those scientific objectives are achieved by using three tracking detectors symmetrically arranged around the interaction point called IP5. The control system is based on a C++ software that allows the user, by means of a graphical interface, direct access to hardware and handling of devices configuration. A first release of the software was designed as a monolithic block, with all functionalities being merged together. Such approach showed soon its limits, mainly poor reusability and maintainability of the source code, evident not only in phase of bug-fixing, but also when one wants to extend functionalities or apply some other modifications. This led to the decision of a radical redesign of the software, now based on the dialogue (message-passing) among separate building blocks. Thanks to the acquired extensibility, the software gained new features and now is a complete tool by which it is possible not only to configure different devices interfacing with a large subset of buses like I2C and VME, but also to do data acquisition both for calibration and physics runs. Furthermore, the software lets the user set up a series of operations to be executed sequentially to handle complex operations. To achieve maximum flexibility, the program units may be run either as a single process or as separate processes on different PCs which exchange messages over the network, thus allowing remote control of the system. Portability is ensured by the adoption of the ASIO (Asynchronous Input Output) library of Boost, a cross-platform suite of libraries which is candidate to become part of the C++ 11 standard. We present the state of the art of this project and outline the future perspectives. In particular, we describe the system architecture and the message-passing scheme. We also report on the results obtained in a first complete test of the software both as a single process and on two PCs.

Tracing how normative messages may influence physical activity intention

USDA-ARS?s Scientific Manuscript database

Normative messages have been shown to increase intention to do physical activity (PA). We traced how 'positive' and 'negative' normative messages influenced PA intention by comparing constructs of the model of goal-directed behaviour with descriptive norms (MGDB+DN) across control and treatment grou...

Evaluation of a new parallel numerical parameter optimization algorithm for a dynamical system

NASA Astrophysics Data System (ADS)

Duran, Ahmet; Tuncel, Mehmet

2016-10-01

It is important to have a scalable parallel numerical parameter optimization algorithm for a dynamical system used in financial applications where time limitation is crucial. We use Message Passing Interface parallel programming and present such a new parallel algorithm for parameter estimation. For example, we apply the algorithm to the asset flow differential equations that have been developed and analyzed since 1989 (see [3-6] and references contained therein). We achieved speed-up for some time series to run up to 512 cores (see [10]). Unlike [10], we consider more extensive financial market situations, for example, in presence of low volatility, high volatility and stock market price at a discount/premium to its net asset value with varying magnitude, in this work. Moreover, we evaluated the convergence of the model parameter vector, the nonlinear least squares error and maximum improvement factor to quantify the success of the optimization process depending on the number of initial parameter vectors.

A De-centralized Scheduling and Load Balancing Algorithm for Heterogeneous Grid Environments

NASA Technical Reports Server (NTRS)

Arora, Manish; Das, Sajal K.; Biswas, Rupak

2002-01-01

In the past two decades, numerous scheduling and load balancing techniques have been proposed for locally distributed multiprocessor systems. However, they all suffer from significant deficiencies when extended to a Grid environment: some use a centralized approach that renders the algorithm unscalable, while others assume the overhead involved in searching for appropriate resources to be negligible. Furthermore, classical scheduling algorithms do not consider a Grid node to be N-resource rich and merely work towards maximizing the utilization of one of the resources. In this paper, we propose a new scheduling and load balancing algorithm for a generalized Grid model of N-resource nodes that not only takes into account the node and network heterogeneity, but also considers the overhead involved in coordinating among the nodes. Our algorithm is decentralized, scalable, and overlaps the node coordination time with that of the actual processing of ready jobs, thus saving valuable clock cycles needed for making decisions. The proposed algorithm is studied by conducting simulations using the Message Passing Interface (MPI) paradigm.

A De-Centralized Scheduling and Load Balancing Algorithm for Heterogeneous Grid Environments

NASA Technical Reports Server (NTRS)

Arora, Manish; Das, Sajal K.; Biswas, Rupak; Biegel, Bryan (Technical Monitor)

2002-01-01

In the past two decades, numerous scheduling and load balancing techniques have been proposed for locally distributed multiprocessor systems. However, they all suffer from significant deficiencies when extended to a Grid environment: some use a centralized approach that renders the algorithm unscalable, while others assume the overhead involved in searching for appropriate resources to be negligible. Furthermore, classical scheduling algorithms do not consider a Grid node to be N-resource rich and merely work towards maximizing the utilization of one of the resources. In this paper we propose a new scheduling and load balancing algorithm for a generalized Grid model of N-resource nodes that not only takes into account the node and network heterogeneity, but also considers the overhead involved in coordinating among the nodes. Our algorithm is de-centralized, scalable, and overlaps the node coordination time of the actual processing of ready jobs, thus saving valuable clock cycles needed for making decisions. The proposed algorithm is studied by conducting simulations using the Message Passing Interface (MPI) paradigm.

Parallel Computing of Upwelling in a Rotating Stratified Flow

NASA Astrophysics Data System (ADS)

Cui, A.; Street, R. L.

1997-11-01

A code for the three-dimensional, unsteady, incompressible, and turbulent flow has been implemented on the IBM SP2, using message passing. The effects of rotation and variable density are included. A finite volume method is used to discretize the Navier-Stokes equations in general curvilinear coordinates on a non-staggered grid. All the spatial derivatives are approximated using second-order central differences with the exception of the convection terms, which are handled with special upwind-difference schemes. The semi-implicit, second-order accurate, time-advancement scheme employs the Adams-Bashforth method for the explicit terms and Crank-Nicolson for the implicit terms. A multigrid method, with the four-color ZEBRA as smoother, is used to solve the Poisson equation for pressure, while the momentum equations are solved with an approximate factorization technique. The code was successfully validated for a variety test cases. Simulations of a laboratory model of coastal upwelling in a rotating annulus are in progress and will be presented.

Phase diagram of matrix compressed sensing

NASA Astrophysics Data System (ADS)

Schülke, Christophe; Schniter, Philip; Zdeborová, Lenka

2016-12-01

In the problem of matrix compressed sensing, we aim to recover a low-rank matrix from a few noisy linear measurements. In this contribution, we analyze the asymptotic performance of a Bayes-optimal inference procedure for a model where the matrix to be recovered is a product of random matrices. The results that we obtain using the replica method describe the state evolution of the Parametric Bilinear Generalized Approximate Message Passing (P-BiG-AMP) algorithm, recently introduced in J. T. Parker and P. Schniter [IEEE J. Select. Top. Signal Process. 10, 795 (2016), 10.1109/JSTSP.2016.2539123]. We show the existence of two different types of phase transition and their implications for the solvability of the problem, and we compare the results of our theoretical analysis to the numerical performance reached by P-BiG-AMP. Remarkably, the asymptotic replica equations for matrix compressed sensing are the same as those for a related but formally different problem of matrix factorization.

The New BaBar Data Reconstruction Control System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ceseracciu, Antonio

2003-06-02

The BaBar experiment is characterized by extremely high luminosity, a complex detector, and a huge data volume, with increasing requirements each year. To fulfill these requirements a new control system has been designed and developed for the offline data reconstruction system. The new control system described in this paper provides the performance and flexibility needed to manage a large number of small computing farms, and takes full benefit of OO design. The infrastructure is well isolated from the processing layer, it is generic and flexible, based on a light framework providing message passing and cooperative multitasking. The system is activelymore » distributed, enforces the separation between different processing tiers by using different naming domains, and glues them together by dedicated brokers. It provides a powerful Finite State Machine framework to describe custom processing models in a simple regular language. This paper describes this new control system, currently in use at SLAC and Padova on {approx}450 CPUs organized in 12 farms.« less

The BaBar Data Reconstruction Control System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ceseracciu, A

2005-04-20

The BaBar experiment is characterized by extremely high luminosity and very large volume of data produced and stored, with increasing computing requirements each year. To fulfill these requirements a Control System has been designed and developed for the offline distributed data reconstruction system. The control system described in this paper provides the performance and flexibility needed to manage a large number of small computing farms, and takes full benefit of OO design. The infrastructure is well isolated from the processing layer, it is generic and flexible, based on a light framework providing message passing and cooperative multitasking. The system ismore » distributed in a hierarchical way: the top-level system is organized in farms, farms in services, and services in subservices or code modules. It provides a powerful Finite State Machine framework to describe custom processing models in a simple regular language. This paper describes the design and evolution of this control system, currently in use at SLAC and Padova on {approx}450 CPUs organized in 9 farms.« less

The BaBar Data Reconstruction Control System

NASA Astrophysics Data System (ADS)

Ceseracciu, A.; Piemontese, M.; Tehrani, F. S.; Pulliam, T. M.; Galeazzi, F.

2005-08-01

The BaBar experiment is characterized by extremely high luminosity and very large volume of data produced and stored, with increasing computing requirements each year. To fulfill these requirements a control system has been designed and developed for the offline distributed data reconstruction system. The control system described in this paper provides the performance and flexibility needed to manage a large number of small computing farms, and takes full benefit of object oriented (OO) design. The infrastructure is well isolated from the processing layer, it is generic and flexible, based on a light framework providing message passing and cooperative multitasking. The system is distributed in a hierarchical way: the top-level system is organized in farms, farms in services, and services in subservices or code modules. It provides a powerful finite state machine framework to describe custom processing models in a simple regular language. This paper describes the design and evolution of this control system, currently in use at SLAC and Padova on /spl sim/450 CPUs organized in nine farms.

Scalable detection of statistically significant communities and hierarchies, using message passing for modularity

PubMed Central

Zhang, Pan; Moore, Cristopher

2014-01-01

Modularity is a popular measure of community structure. However, maximizing the modularity can lead to many competing partitions, with almost the same modularity, that are poorly correlated with each other. It can also produce illusory ‘‘communities’’ in random graphs where none exist. We address this problem by using the modularity as a Hamiltonian at finite temperature and using an efficient belief propagation algorithm to obtain the consensus of many partitions with high modularity, rather than looking for a single partition that maximizes it. We show analytically and numerically that the proposed algorithm works all of the way down to the detectability transition in networks generated by the stochastic block model. It also performs well on real-world networks, revealing large communities in some networks where previous work has claimed no communities exist. Finally we show that by applying our algorithm recursively, subdividing communities until no statistically significant subcommunities can be found, we can detect hierarchical structure in real-world networks more efficiently than previous methods. PMID:25489096

Load Balancing Strategies for Multiphase Flows on Structured Grids

NASA Astrophysics Data System (ADS)

Olshefski, Kristopher; Owkes, Mark

2017-11-01

The computation time required to perform large simulations of complex systems is currently one of the leading bottlenecks of computational research. Parallelization allows multiple processing cores to perform calculations simultaneously and reduces computational times. However, load imbalances between processors waste computing resources as processors wait for others to complete imbalanced tasks. In multiphase flows, these imbalances arise due to the additional computational effort required at the gas-liquid interface. However, many current load balancing schemes are only designed for unstructured grid applications. The purpose of this research is to develop a load balancing strategy while maintaining the simplicity of a structured grid. Several approaches are investigated including brute force oversubscription, node oversubscription through Message Passing Interface (MPI) commands, and shared memory load balancing using OpenMP. Each of these strategies are tested with a simple one-dimensional model prior to implementation into the three-dimensional NGA code. Current results show load balancing will reduce computational time by at least 30%.

Preconditioned implicit solvers for the Navier-Stokes equations on distributed-memory machines

NASA Technical Reports Server (NTRS)

Ajmani, Kumud; Liou, Meng-Sing; Dyson, Rodger W.

1994-01-01

The GMRES method is parallelized, and combined with local preconditioning to construct an implicit parallel solver to obtain steady-state solutions for the Navier-Stokes equations of fluid flow on distributed-memory machines. The new implicit parallel solver is designed to preserve the convergence rate of the equivalent 'serial' solver. A static domain-decomposition is used to partition the computational domain amongst the available processing nodes of the parallel machine. The SPMD (Single-Program Multiple-Data) programming model is combined with message-passing tools to develop the parallel code on a 32-node Intel Hypercube and a 512-node Intel Delta machine. The implicit parallel solver is validated for internal and external flow problems, and is found to compare identically with flow solutions obtained on a Cray Y-MP/8. A peak computational speed of 2300 MFlops/sec has been achieved on 512 nodes of the Intel Delta machine,k for a problem size of 1024 K equations (256 K grid points).

A hybrid neurogenetic approach for stock forecasting.

PubMed

Kwon, Yung-Keun; Moon, Byung-Ro

2007-05-01

In this paper, we propose a hybrid neurogenetic system for stock trading. A recurrent neural network (NN) having one hidden layer is used for the prediction model. The input features are generated from a number of technical indicators being used by financial experts. The genetic algorithm (GA) optimizes the NN's weights under a 2-D encoding and crossover. We devised a context-based ensemble method of NNs which dynamically changes on the basis of the test day's context. To reduce the time in processing mass data, we parallelized the GA on a Linux cluster system using message passing interface. We tested the proposed method with 36 companies in NYSE and NASDAQ for 13 years from 1992 to 2004. The neurogenetic hybrid showed notable improvement on the average over the buy-and-hold strategy and the context-based ensemble further improved the results. We also observed that some companies were more predictable than others, which implies that the proposed neurogenetic hybrid can be used for financial portfolio construction.

Bistatic scattering from a three-dimensional object above a two-dimensional randomly rough surface modeled with the parallel FDTD approach.

PubMed

Guo, L-X; Li, J; Zeng, H

2009-11-01

We present an investigation of the electromagnetic scattering from a three-dimensional (3-D) object above a two-dimensional (2-D) randomly rough surface. A Message Passing Interface-based parallel finite-difference time-domain (FDTD) approach is used, and the uniaxial perfectly matched layer (UPML) medium is adopted for truncation of the FDTD lattices, in which the finite-difference equations can be used for the total computation domain by properly choosing the uniaxial parameters. This makes the parallel FDTD algorithm easier to implement. The parallel performance with different number of processors is illustrated for one rough surface realization and shows that the computation time of our parallel FDTD algorithm is dramatically reduced relative to a single-processor implementation. Finally, the composite scattering coefficients versus scattered and azimuthal angle are presented and analyzed for different conditions, including the surface roughness, the dielectric constants, the polarization, and the size of the 3-D object.

Parallel Navier-Stokes computations on shared and distributed memory architectures

NASA Technical Reports Server (NTRS)

Hayder, M. Ehtesham; Jayasimha, D. N.; Pillay, Sasi Kumar

1995-01-01

We study a high order finite difference scheme to solve the time accurate flow field of a jet using the compressible Navier-Stokes equations. As part of our ongoing efforts, we have implemented our numerical model on three parallel computing platforms to study the computational, communication, and scalability characteristics. The platforms chosen for this study are a cluster of workstations connected through fast networks (the LACE experimental testbed at NASA Lewis), a shared memory multiprocessor (the Cray YMP), and a distributed memory multiprocessor (the IBM SPI). Our focus in this study is on the LACE testbed. We present some results for the Cray YMP and the IBM SP1 mainly for comparison purposes. On the LACE testbed, we study: (1) the communication characteristics of Ethernet, FDDI, and the ALLNODE networks and (2) the overheads induced by the PVM message passing library used for parallelizing the application. We demonstrate that clustering of workstations is effective and has the potential to be computationally competitive with supercomputers at a fraction of the cost.

Understanding narrative effects: The role of discrete negative emotions on message processing and attitudes among low-income African American women

PubMed Central

Yoo, Jina H.; Kreuter, Matthew W.; Lai, Choi; Fu, Qiang

2014-01-01

This study tests the processes through which breast cancer narrative messages are effective by taking a functional approach. We explore how discrete negative emotions (i.e., sadness, fear, and anger) induced by breast cancer survivor stories affect African American women’s message processing, recall of message content, and attitudinal outcomes. Structural equation modeling was performed for narrative and informational versions of a breast cancer screening video shown to 409 low-income African American women ages 40 and older. The model was well fitted. Sadness enhanced the persuasive process, while fear inhibited it. Sadness also helped participants recall more message-relevant content, while fear inhibited recall. Anger was not related to the persuasive process. Implications of these findings for narrative research and application are discussed. PMID:24111724

Cognitive Processing of Fear-Arousing Message Content.

ERIC Educational Resources Information Center

Hale, Jerold L.; And Others

1995-01-01

Investigates two models (the Elaboration Likelihood Model and the Heuristic-Systematic Model) of the cognitive processing of fear-arousing messages in undergraduate students. Finds in three of the four conditions (low fear, high fear, high trait anxiety) that cognitive processing appears to be antagonistic. Finds some evidence of concurrent…

Towards a HPC-oriented parallel implementation of a learning algorithm for bioinformatics applications

PubMed Central

2014-01-01

Background The huge quantity of data produced in Biomedical research needs sophisticated algorithmic methodologies for its storage, analysis, and processing. High Performance Computing (HPC) appears as a magic bullet in this challenge. However, several hard to solve parallelization and load balancing problems arise in this context. Here we discuss the HPC-oriented implementation of a general purpose learning algorithm, originally conceived for DNA analysis and recently extended to treat uncertainty on data (U-BRAIN). The U-BRAIN algorithm is a learning algorithm that finds a Boolean formula in disjunctive normal form (DNF), of approximately minimum complexity, that is consistent with a set of data (instances) which may have missing bits. The conjunctive terms of the formula are computed in an iterative way by identifying, from the given data, a family of sets of conditions that must be satisfied by all the positive instances and violated by all the negative ones; such conditions allow the computation of a set of coefficients (relevances) for each attribute (literal), that form a probability distribution, allowing the selection of the term literals. The great versatility that characterizes it, makes U-BRAIN applicable in many of the fields in which there are data to be analyzed. However the memory and the execution time required by the running are of O(n3) and of O(n5) order, respectively, and so, the algorithm is unaffordable for huge data sets. Results We find mathematical and programming solutions able to lead us towards the implementation of the algorithm U-BRAIN on parallel computers. First we give a Dynamic Programming model of the U-BRAIN algorithm, then we minimize the representation of the relevances. When the data are of great size we are forced to use the mass memory, and depending on where the data are actually stored, the access times can be quite different. According to the evaluation of algorithmic efficiency based on the Disk Model, in order to reduce the costs of the communications between different memories (RAM, Cache, Mass, Virtual) and to achieve efficient I/O performance, we design a mass storage structure able to access its data with a high degree of temporal and spatial locality. Then we develop a parallel implementation of the algorithm. We model it as a SPMD system together to a Message-Passing Programming Paradigm. Here, we adopt the high-level message-passing systems MPI (Message Passing Interface) in the version for the Java programming language, MPJ. The parallel processing is organized into four stages: partitioning, communication, agglomeration and mapping. The decomposition of the U-BRAIN algorithm determines the necessity of a communication protocol design among the processors involved. Efficient synchronization design is also discussed. Conclusions In the context of a collaboration between public and private institutions, the parallel model of U-BRAIN has been implemented and tested on the INTEL XEON E7xxx and E5xxx family of the CRESCO structure of Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), developed in the framework of the European Grid Infrastructure (EGI), a series of efforts to provide access to high-throughput computing resources across Europe using grid computing techniques. The implementation is able to minimize both the memory space and the execution time. The test data used in this study are IPDATA (Irvine Primate splice- junction DATA set), a subset of HS3D (Homo Sapiens Splice Sites Dataset) and a subset of COSMIC (the Catalogue of Somatic Mutations in Cancer). The execution time and the speed-up on IPDATA reach the best values within about 90 processors. Then the parallelization advantage is balanced by the greater cost of non-local communications between the processors. A similar behaviour is evident on HS3D, but at a greater number of processors, so evidencing the direct relationship between data size and parallelization gain. This behaviour is confirmed on COSMIC. Overall, the results obtained show that the parallel version is up to 30 times faster than the serial one. PMID:25077818

Towards a HPC-oriented parallel implementation of a learning algorithm for bioinformatics applications.

PubMed

D'Angelo, Gianni; Rampone, Salvatore

2014-01-01

The huge quantity of data produced in Biomedical research needs sophisticated algorithmic methodologies for its storage, analysis, and processing. High Performance Computing (HPC) appears as a magic bullet in this challenge. However, several hard to solve parallelization and load balancing problems arise in this context. Here we discuss the HPC-oriented implementation of a general purpose learning algorithm, originally conceived for DNA analysis and recently extended to treat uncertainty on data (U-BRAIN). The U-BRAIN algorithm is a learning algorithm that finds a Boolean formula in disjunctive normal form (DNF), of approximately minimum complexity, that is consistent with a set of data (instances) which may have missing bits. The conjunctive terms of the formula are computed in an iterative way by identifying, from the given data, a family of sets of conditions that must be satisfied by all the positive instances and violated by all the negative ones; such conditions allow the computation of a set of coefficients (relevances) for each attribute (literal), that form a probability distribution, allowing the selection of the term literals. The great versatility that characterizes it, makes U-BRAIN applicable in many of the fields in which there are data to be analyzed. However the memory and the execution time required by the running are of O(n(3)) and of O(n(5)) order, respectively, and so, the algorithm is unaffordable for huge data sets. We find mathematical and programming solutions able to lead us towards the implementation of the algorithm U-BRAIN on parallel computers. First we give a Dynamic Programming model of the U-BRAIN algorithm, then we minimize the representation of the relevances. When the data are of great size we are forced to use the mass memory, and depending on where the data are actually stored, the access times can be quite different. According to the evaluation of algorithmic efficiency based on the Disk Model, in order to reduce the costs of the communications between different memories (RAM, Cache, Mass, Virtual) and to achieve efficient I/O performance, we design a mass storage structure able to access its data with a high degree of temporal and spatial locality. Then we develop a parallel implementation of the algorithm. We model it as a SPMD system together to a Message-Passing Programming Paradigm. Here, we adopt the high-level message-passing systems MPI (Message Passing Interface) in the version for the Java programming language, MPJ. The parallel processing is organized into four stages: partitioning, communication, agglomeration and mapping. The decomposition of the U-BRAIN algorithm determines the necessity of a communication protocol design among the processors involved. Efficient synchronization design is also discussed. In the context of a collaboration between public and private institutions, the parallel model of U-BRAIN has been implemented and tested on the INTEL XEON E7xxx and E5xxx family of the CRESCO structure of Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), developed in the framework of the European Grid Infrastructure (EGI), a series of efforts to provide access to high-throughput computing resources across Europe using grid computing techniques. The implementation is able to minimize both the memory space and the execution time. The test data used in this study are IPDATA (Irvine Primate splice- junction DATA set), a subset of HS3D (Homo Sapiens Splice Sites Dataset) and a subset of COSMIC (the Catalogue of Somatic Mutations in Cancer). The execution time and the speed-up on IPDATA reach the best values within about 90 processors. Then the parallelization advantage is balanced by the greater cost of non-local communications between the processors. A similar behaviour is evident on HS3D, but at a greater number of processors, so evidencing the direct relationship between data size and parallelization gain. This behaviour is confirmed on COSMIC. Overall, the results obtained show that the parallel version is up to 30 times faster than the serial one.

ms2: A molecular simulation tool for thermodynamic properties

NASA Astrophysics Data System (ADS)

Deublein, Stephan; Eckl, Bernhard; Stoll, Jürgen; Lishchuk, Sergey V.; Guevara-Carrion, Gabriela; Glass, Colin W.; Merker, Thorsten; Bernreuther, Martin; Hasse, Hans; Vrabec, Jadran

2011-11-01

This work presents the molecular simulation program ms2 that is designed for the calculation of thermodynamic properties of bulk fluids in equilibrium consisting of small electro-neutral molecules. ms2 features the two main molecular simulation techniques, molecular dynamics (MD) and Monte-Carlo. It supports the calculation of vapor-liquid equilibria of pure fluids and multi-component mixtures described by rigid molecular models on the basis of the grand equilibrium method. Furthermore, it is capable of sampling various classical ensembles and yields numerous thermodynamic properties. To evaluate the chemical potential, Widom's test molecule method and gradual insertion are implemented. Transport properties are determined by equilibrium MD simulations following the Green-Kubo formalism. ms2 is designed to meet the requirements of academia and industry, particularly achieving short response times and straightforward handling. It is written in Fortran90 and optimized for a fast execution on a broad range of computer architectures, spanning from single processor PCs over PC-clusters and vector computers to high-end parallel machines. The standard Message Passing Interface (MPI) is used for parallelization and ms2 is therefore easily portable to different computing platforms. Feature tools facilitate the interaction with the code and the interpretation of input and output files. The accuracy and reliability of ms2 has been shown for a large variety of fluids in preceding work. Program summaryProgram title:ms2 Catalogue identifier: AEJF_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEJF_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Special Licence supplied by the authors No. of lines in distributed program, including test data, etc.: 82 794 No. of bytes in distributed program, including test data, etc.: 793 705 Distribution format: tar.gz Programming language: Fortran90 Computer: The simulation tool ms2 is usable on a wide variety of platforms, from single processor machines over PC-clusters and vector computers to vector-parallel architectures. (Tested with Fortran compilers: gfortran, Intel, PathScale, Portland Group and Sun Studio.) Operating system: Unix/Linux, Windows Has the code been vectorized or parallelized?: Yes. Message Passing Interface (MPI) protocol Scalability. Excellent scalability up to 16 processors for molecular dynamics and >512 processors for Monte-Carlo simulations. RAM:ms2 runs on single processors with 512 MB RAM. The memory demand rises with increasing number of processors used per node and increasing number of molecules. Classification: 7.7, 7.9, 12 External routines: Message Passing Interface (MPI) Nature of problem: Calculation of application oriented thermodynamic properties for rigid electro-neutral molecules: vapor-liquid equilibria, thermal and caloric data as well as transport properties of pure fluids and multi-component mixtures. Solution method: Molecular dynamics, Monte-Carlo, various classical ensembles, grand equilibrium method, Green-Kubo formalism. Restrictions: No. The system size is user-defined. Typical problems addressed by ms2 can be solved by simulating systems containing typically 2000 molecules or less. Unusual features: Feature tools are available for creating input files, analyzing simulation results and visualizing molecular trajectories. Additional comments: Sample makefiles for multiple operation platforms are provided. Documentation is provided with the installation package and is available at http://www.ms-2.de. Running time: The running time of ms2 depends on the problem set, the system size and the number of processes used in the simulation. Running four processes on a "Nehalem" processor, simulations calculating VLE data take between two and twelve hours, calculating transport properties between six and 24 hours.

Text messaging to support a perinatal collaborative care model for depression: A multi-methods inquiry.

PubMed

Bhat, Amritha; Mao, Johnny; Unützer, Jürgen; Reed, Susan; Unger, Jennifer

Mental health care integrated into obstetric settings improves access to perinatal depression treatments. Digital interactions such as text messaging between patient and provider can further improve access. We describe the use of text messaging within a perinatal Collaborative Care (CC) program, and explore the association of text messaging content with perinatal depression outcomes. We analyzed data from an open treatment trial of perinatal CC in a rural obstetric clinic. Twenty five women with Patient Health Questionnaire-9 score of ≥10 enrolled in CC, and used text messaging to communicate with their Care Manager(CM). We used surveys and focus groups to assessacceptability of text messaging with surveys and focus groups. We calculated the number of text messages exchanged, and analyzed content to understand usage patterns. We explored association between text messaging content and depression outcomes. CMs initiated 85.4% messages, and patients responded to 86.9% messages. CMs used text messaging for appointment reminders, and patients used it to obtain obstetric and parenting information. CMs had concerns about the likelihood of boundary violations. Patients appreciated the asynchronous nature of text messaging. Text messaging is feasible and acceptable within a perinatal CC program. We need further research into the effectiveness of text messaging content, and response protocols. Copyright © 2018 Elsevier Inc. All rights reserved.

Sequence2Vec: a novel embedding approach for modeling transcription factor binding affinity landscape.

PubMed

Dai, Hanjun; Umarov, Ramzan; Kuwahara, Hiroyuki; Li, Yu; Song, Le; Gao, Xin

2017-11-15

An accurate characterization of transcription factor (TF)-DNA affinity landscape is crucial to a quantitative understanding of the molecular mechanisms underpinning endogenous gene regulation. While recent advances in biotechnology have brought the opportunity for building binding affinity prediction methods, the accurate characterization of TF-DNA binding affinity landscape still remains a challenging problem. Here we propose a novel sequence embedding approach for modeling the transcription factor binding affinity landscape. Our method represents DNA binding sequences as a hidden Markov model which captures both position specific information and long-range dependency in the sequence. A cornerstone of our method is a novel message passing-like embedding algorithm, called Sequence2Vec, which maps these hidden Markov models into a common nonlinear feature space and uses these embedded features to build a predictive model. Our method is a novel combination of the strength of probabilistic graphical models, feature space embedding and deep learning. We conducted comprehensive experiments on over 90 large-scale TF-DNA datasets which were measured by different high-throughput experimental technologies. Sequence2Vec outperforms alternative machine learning methods as well as the state-of-the-art binding affinity prediction methods. Our program is freely available at https://github.com/ramzan1990/sequence2vec. xin.gao@kaust.edu.sa or lsong@cc.gatech.edu. Supplementary data are available at Bioinformatics online. © The Author(s) 2017. Published by Oxford University Press.

A distributed Clips implementation: dClips

NASA Technical Reports Server (NTRS)

Li, Y. Philip

1993-01-01

A distributed version of the Clips language, dClips, was implemented on top of two existing generic distributed messaging systems to show that: (1) it is easy to create a coarse-grained parallel programming environment out of an existing language if a high level messaging system is used; and (2) the computing model of a parallel programming environment can be changed easily if we change the underlying messaging system. dClips processes were first connected with a simple master-slave model. A client-server model with intercommunicating agents was later implemented. The concept of service broker is being investigated.

Modeling a maintenance simulation of the geosynchronous platform

NASA Technical Reports Server (NTRS)

Kleiner, A. F., Jr.

1980-01-01

A modeling technique used to conduct a simulation study comparing various maintenance routines for a space platform is dicussed. A system model is described and illustrated, the basic concepts of a simulation pass are detailed, and sections on failures and maintenance are included. The operation of the system across time is best modeled by a discrete event approach with two basic events - failure and maintenance of the system. Each overall simulation run consists of introducing a particular model of the physical system, together with a maintenance policy, demand function, and mission lifetime. The system is then run through many passes, each pass corresponding to one mission and the model is re-initialized before each pass. Statistics are compiled at the end of each pass and after the last pass a report is printed. Items of interest typically include the time to first maintenance, total number of maintenance trips for each pass, average capability of the system, etc.

Expectancy Theory in Media and Message Selection.

ERIC Educational Resources Information Center

Van Leuven, Jim

1981-01-01

Argues for reversing emphasis on uses and gratifications research in favor of an expectancy model which holds that selection of a particular medium depends on (1) the expectation that the choice will be followed by a message of interest and (2) the importance of that message in satisfying user's values. (PD)

Messages about Sexuality: An Ecological Perspective

ERIC Educational Resources Information Center

Boone, Tanya L.

2015-01-01

The goal of this two-part study was to identify the perceived influence of sexuality messages from parents, peers, school and the media--four microsystems within the Ecological Model--on emerging adult US college women's sexual attitudes. Findings suggest that parents were the most likely source of the message to "remain abstinent until…

Extending the explanatory utility of the EPPM beyond fear-based persuasion.

PubMed

Lewis, Ioni; Watson, Barry; White, Katherine M

2013-01-01

In the 20 years since its inception, the Extended Parallel Process Model (EPPM) has attracted much empirical support. Currently, and unsurprisingly, given that is a model of fear-based persuasion, the EPPM's explanatory utility has been based only upon fear-based messages. However, an argument is put forth herein that draws upon existing evidence that the EPPM may be an efficacious framework for explaining the persuasive process and outcomes of emotion-based messages more broadly when such messages are addressing serious health topics. For the current study, four different types of emotional appeals were purposefully devised and included a fear-, an annoyance/agitation-, a pride-, and a humor-based message. All messages addressed the serious health issue of road safety, and in particular the risky behavior of speeding. Participants (n = 551) were exposed to only one of the four messages and subsequently provided responses within a survey. A series of 2 (threat: low, high) × 2 (efficacy: low, high) analysis of variance was conducted for each of the appeals based on the EPPM's message outcomes of acceptance and rejection. Support was found for the EPPM with a number of main effects of threat and efficacy emerging, reflecting that, irrespective of emotional appeal type, high levels of threat and efficacy enhanced message outcomes via maximizing acceptance and minimizing rejection. Theoretically, the findings provide support for the explanatory utility of the EPPM for emotion-based health messages more broadly. In an applied sense, the findings highlight the value of adopting the EPPM as a framework when devising and evaluating emotion-based health messages for serious health topics.

Hypertext: Improved Capability for Shipboard Naval Messages

DTIC Science & Technology

1989-09-01

message handling system; a complete working model of the system has not been developed . 3 D. ORGANIZATION OF STUDY 1. The "Paperless" Ship Initiative...work in tandem to improve afloat message handling procedures. The objective of the PCMT project is to develop a system that could be installed on...working group has identified a list of requirements to guide the DoD’s progress towards improving its message communication system. These

Distributed memory compiler design for sparse problems

NASA Technical Reports Server (NTRS)

Wu, Janet; Saltz, Joel; Berryman, Harry; Hiranandani, Seema

1991-01-01

A compiler and runtime support mechanism is described and demonstrated. The methods presented are capable of solving a wide range of sparse and unstructured problems in scientific computing. The compiler takes as input a FORTRAN 77 program enhanced with specifications for distributing data, and the compiler outputs a message passing program that runs on a distributed memory computer. The runtime support for this compiler is a library of primitives designed to efficiently support irregular patterns of distributed array accesses and irregular distributed array partitions. A variety of Intel iPSC/860 performance results obtained through the use of this compiler are presented.

A Scalable Architecture of a Structured LDPC Decoder

NASA Technical Reports Server (NTRS)

Lee, Jason Kwok-San; Lee, Benjamin; Thorpe, Jeremy; Andrews, Kenneth; Dolinar, Sam; Hamkins, Jon

2004-01-01

We present a scalable decoding architecture for a certain class of structured LDPC codes. The codes are designed using a small (n,r) protograph that is replicated Z times to produce a decoding graph for a (Z x n, Z x r) code. Using this architecture, we have implemented a decoder for a (4096,2048) LDPC code on a Xilinx Virtex-II 2000 FPGA, and achieved decoding speeds of 31 Mbps with 10 fixed iterations. The implemented message-passing algorithm uses an optimized 3-bit non-uniform quantizer that operates with 0.2dB implementation loss relative to a floating point decoder.

''Towards a High-Performance and Robust Implementation of MPI-IO on Top of GPFS''

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prost, J.P.; Tremann, R.; Blackwore, R.

2000-01-11

MPI-IO/GPFS is a prototype implementation of the I/O chapter of the Message Passing Interface (MPI) 2 standard. It uses the IBM General Parallel File System (GPFS), with prototyped extensions, as the underlying file system. this paper describes the features of this prototype which support its high performance and robustness. The use of hints at the file system level and at the MPI-IO level allows tailoring the use of the file system to the application needs. Error handling in collective operations provides robust error reporting and deadlock prevention in case of returning errors.

Scalability and Portability of Two Parallel Implementations of ADI

NASA Technical Reports Server (NTRS)

Phung, Thanh; VanderWijngaart, Rob F.

1994-01-01

Two domain decompositions for the implementation of the NAS Scalar Penta-diagonal Parallel Benchmark on MIMD systems are investigated, namely transposition and multi-partitioning. Hardware platforms considered are the Intel iPSC/860 and Paragon XP/S-15, and clusters of SGI workstations on ethernet, communicating through PVM. It is found that the multi-partitioning strategy offers the kind of coarse granularity that allows scaling up to hundreds of processors on a massively parallel machine. Moreover, efficiency is retained when the code is ported verbatim (save message passing syntax) to a PVM environment on a modest size cluster of workstations.

Chronology of the birth and death of a health bill.

PubMed

Jacks, J C; Jacks, L

1995-01-01

A two-year attempt by the Clinton administration to develop and pass a health care reform bill was from the beginning destined for failure. The health care reform plan was developed in secret, leaving the plan open for special interest suspect. It was overly complex and difficult to understand. Congress and the general public initially supported the effort, but wavered under pressure and negative messages generated by special interest groups. After a year of intense debate, health care reform was declared dead, with very little hope of resurrection in the 1994 election year, which saw Republicans make significant gains in Congress.

Distributed-Memory Computing With the Langley Aerothermodynamic Upwind Relaxation Algorithm (LAURA)

NASA Technical Reports Server (NTRS)

Riley, Christopher J.; Cheatwood, F. McNeil

1997-01-01

The Langley Aerothermodynamic Upwind Relaxation Algorithm (LAURA), a Navier-Stokes solver, has been modified for use in a parallel, distributed-memory environment using the Message-Passing Interface (MPI) standard. A standard domain decomposition strategy is used in which the computational domain is divided into subdomains with each subdomain assigned to a processor. Performance is examined on dedicated parallel machines and a network of desktop workstations. The effect of domain decomposition and frequency of boundary updates on performance and convergence is also examined for several realistic configurations and conditions typical of large-scale computational fluid dynamic analysis.

Overview of Sparse Graph for Multiple Access in Future Mobile Networks

NASA Astrophysics Data System (ADS)

Lei, Jing; Li, Baoguo; Li, Erbao; Gong, Zhenghui

2017-10-01

Multiple access via sparse graph, such as low density signature (LDS) and sparse code multiple access (SCMA), is a promising technique for future wireless communications. This survey presents an overview of the developments in this burgeoning field, including transmitter structures, extrinsic information transform (EXIT) chart analysis and comparisons with existing multiple access techniques. Such technique enables multiple access under overloaded conditions to achieve a satisfactory performance. Message passing algorithm is utilized for multi-user detection in the receiver, and structures of the sparse graph are illustrated in detail. Outlooks and challenges of this technique are also presented.

Developing and Testing Rational Models of Message Design.

ERIC Educational Resources Information Center

O'Keefe, Barbara J.

1992-01-01

Responds to an article in the same issue regarding research methods for conversational cognition. Argues for a noncognitive view of rational models in communication research. Sets out an analysis of the kinds of claims made by rational models of message design. Discusses the implications of this analysis for studies of the cognitive processes…

Tracing How Normative Messages May Influence Physical Activity Intention.

PubMed

van Bavel, René; Esposito, Gabriele; Baranowski, Tom; Duch-Brown, Néstor

2017-04-01

Normative messages have been shown to increase intention to do physical activity. We traced how "positive" and "negative" normative messages influenced physical activity intention by comparing constructs of the model of goal-directed behavior with descriptive norms (MGDB + DNs) across control and treatment groups in an experiment. For this purpose, 16-24-year-old respondents (n = 1,200) in Bulgaria, Croatia, and Romania were asked about their age, sex, and levels of physical activity before being exposed to positive and negative normative messages and completing a questionnaire with MGDB + DNs scales. Different MGDB + DNs constructs were influenced by the normative messages: compared with the control, the negative message group showed stronger attitudes (p = .003) and the positive message group showed higher positive anticipated emotions (p = .005). The positive message's effect is consistent with the literature on conformity to social norms. The negative message's effect lends itself to interpretations based on social identity and deviance regulation theories.

The Prodiguer Messaging Platform

NASA Astrophysics Data System (ADS)

Greenslade, Mark; Denvil, Sebastien; Raciazek, Jerome; Carenton, Nicolas; Levavasseur, Guillame

2014-05-01

CONVERGENCE is a French multi-partner national project designed to gather HPC and informatics expertise to innovate in the context of running French climate models with differing grids and at differing resolutions. Efficient and reliable execution of these models and the management and dissemination of model output (data and meta-data) are just some of the complexities that CONVERGENCE aims to resolve. The Institut Pierre Simon Laplace (IPSL) is responsible for running climate simulations upon a set of heterogenous HPC environments within France. With heterogeneity comes added complexity in terms of simulation instrumentation and control. Obtaining a global perspective upon the state of all simulations running upon all HPC environments has hitherto been problematic. In this presentation we detail how, within the context of CONVERGENCE, the implementation of the Prodiguer messaging platform resolves complexity and permits the development of real-time applications such as: 1. a simulation monitoring dashboard; 2. a simulation metrics visualizer; 3. an automated simulation runtime notifier; 4. an automated output data & meta-data publishing pipeline; The Prodiguer messaging platform leverages a widely used open source message broker software called RabbitMQ. RabbitMQ itself implements the Advanced Message Queue Protocol (AMPQ). Hence it will be demonstrated that the Prodiguer messaging platform is built upon both open source and open standards.

Experimenting with C2 Applications and Federated Infrastructures for Integrated Full-Spectrum Operational Environments in Support of Collaborative Planning and Interoperable Execution

DTIC Science & Technology

2004-06-01

Situation Understanding) Common Operational Pictures Planning & Decision Support Capabilities Message & Order Processing Common Operational...Pictures Planning & Decision Support Capabilities Message & Order Processing Common Languages & Data Models Modeling & Simulation Domain

Message sensation and cognition values: factors of competition or integration?

PubMed

Xu, Jie

2015-01-01

Using the Activation Model of Information Exposure and Elaboration Likelihood Model as theoretical frameworks, this study explored the effects of message sensation value (MSV) and message cognition value (MCV) of antismoking public service announcements (PSAs) on ad processing and evaluation among young adults, and the difference between high sensation seekers and low sensation seekers in their perceptions and responses toward ads with different levels of sensation and cognition value. A 2 (MSV: high vs. low) × 2 (MCV: high vs. low) × 2 (need for sensation: high vs. low) mixed experimental design was conducted. Two physiological measures including skin conductance and heart rate were examined. Findings of this study show that MSV was not a distraction but a facilitator of message persuasiveness. These findings contribute to the activation model. In addition, need for sensation moderated the interaction effect of MSV and MCV on ad processing. Low sensation seekers were more likely to experience the interaction between MSV and MCV than high sensation seekers. Several observations related to the findings and implications for antismoking message designs are elaborated. Limitations and directions for future research are also outlined.

Fear, threat, and perceptions of efficacy from frightening skin cancer messages.

PubMed

Stephenson, M T; Witte, K

1998-01-01

Fear appeal messages were designed and tested to ascertain their effectiveness in promoting skin protective behaviors. Theoretically guided by the Extended Parallel Process Model, the fear appeal messages in this study conveyed the seriousness of exposed and unprotected skin for college students in the Southwestern United States, and recommended a series of behaviors that would protect individuals from serious sunburns. The results demonstrated that fear appeals are effective in promoting skin protective behaviors. Specifically, highly threatening fear appeal messages were most effective when combined with a strong efficacy message emphasizing the effectiveness of the recommended behaviors.

Is Provider Secure Messaging Associated With Patient Messaging Behavior? Evidence From the US Army.

PubMed

Wolcott, Vickee; Agarwal, Ritu; Nelson, D Alan

2017-04-06

Secure messaging with health care providers offers the promise of improved patient-provider relationships, potentially facilitating outcome improvements. But, will patients use messaging technology in the manner envisioned by policy-makers if their providers do not actively use it? We hypothesized that the level and type of secure messaging usage by providers might be associated with messaging initiation by their patients. The study employed a dataset of health care and secure messaging records of more than 81,000 US Army soldiers and nearly 3000 clinicians with access to a patient portal system. We used a negative binomial regression model on over 25 million observations to determine the adjusted association between provider-initiated and provider-response messaging and subsequent messaging by their patients in this population over a 4-year period. Prior provider-initiated and response messaging levels were associated with new patient messaging when controlling for the patient's health care utilization and diagnoses, with the strongest association for high provider-response messaging level. Patients whose providers were highly responsive to the messages of other patients initiated 334% more secure messages (P<.001) than patients with providers who did not personally respond to other patients' messages. Our results indicate that provider messaging usage levels and types thereof predict their patients' subsequent communication behavior. The findings suggest the need for more study into the factors associated with provider messaging to fully understand the mechanisms of this relationship. ©Vickee Wolcott, Ritu Agarwal, D. Alan Nelson. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 06.04.2017.

Adolescent HIV Prevention: An Application of the Elaboration Likelihood Model.

ERIC Educational Resources Information Center

Metzler, April E.; Weiskotten, David; Morgen, Keith J.

Ninth grade students (n=298) participated in a study to examine the influence source credibility, message, quality, and personal relevance on HIV prevention message efficacy. A pilot study with adolescent focus groups created the high and low quality messages, as well as the high (HIV+) and low (worried parent) credibility sources. Participants…

ExxonMobil's Social Responsibility Messaging--2002-2013 CEO Letters

ERIC Educational Resources Information Center

Grantham, Susan; Vieira, Edward T., Jr.

2018-01-01

The purpose of this study was to evaluate ExxonMobil's social responsibility/social responsiveness (SR) communication to determine the company's social responsibility messaging in terms of the Social Responsibility themes of the Triple bottom Line Model (profit, people, planet) and to evaluate if the messaging changed in response to external…

Supervising simulations with the Prodiguer Messaging Platform

NASA Astrophysics Data System (ADS)

Greenslade, Mark; Carenton, Nicolas; Denvil, Sebastien

2015-04-01

At any one moment in time, researchers affiliated with the Institut Pierre Simon Laplace (IPSL) climate modeling group, are running hundreds of global climate simulations. These simulations execute upon a heterogeneous set of High Performance Computing (HPC) environments spread throughout France. The IPSL's simulation execution runtime is called libIGCM (library for IPSL Global Climate Modeling group). libIGCM has recently been enhanced so as to support realtime operational use cases. Such use cases include simulation monitoring, data publication, environment metrics collection, automated simulation control … etc. At the core of this enhancement is the Prodiguer messaging platform. libIGCM now emits information, in the form of messages, for remote processing at IPSL servers in Paris. The remote message processing takes several forms, for example: 1. Persisting message content to database(s); 2. Notifying an operator of changes in a simulation's execution status; 3. Launching rollback jobs upon simulation failure; 4. Dynamically updating controlled vocabularies; 5. Notifying downstream applications such as the Prodiguer web portal; We will describe how the messaging platform has been implemented from a technical perspective and demonstrate the Prodiguer web portal receiving realtime notifications.

The Relationship of Repeated Technical Assistance Support Visits to the Delivery of Positive Health, Dignity, and Prevention (PHDP) Messages by Healthcare Providers in Mozambique: A Longitudinal Multilevel Analysis.

PubMed

Gutin, Sarah A; Amico, K Rivet; Hunguana, Elsa; Munguambe, António Orlando; Rose, Carol Dawson

Positive health, dignity, and prevention (PHDP) is Mozambique's strategy to engage clinicians in the delivery of prevention messages to their HIV-positive clients. This national implementation strategy uses provider trainings on offering key messages and focuses on intervening on 9 evidence-based risk reduction areas. We investigated the impact of longitudinal technical assistance (TA) as an addition to this basic training. We followed 153 healthcare providers in 5 Mozambican provinces over 6 months to evaluate the impact of on-site, observation-based TA on PHDP implementation. Longitudinal multilevel models were estimated to model change in PHDP message delivery over time among individual providers. With each additional TA visit, providers delivered about 1 additional PHDP message ( P < .001); clinicians and nonclinicians started at about the same baseline level, but clinicians improved more quickly ( P = .004). Message delivery varied by practice sector; maternal and child health sectors outperformed other sectors. Longitudinal TA helped reach the programmatic goals of the PHDP program in Mozambique.

An Evaluation of One-Sided and Two-Sided Communication Paradigms on Relaxed-Ordering Interconnect

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ibrahim, Khaled Z.; Hargrove, Paul H.; Iancu, Costin

The Cray Gemini interconnect hardware provides multiple transfer mechanisms and out-of-order message delivery to improve communication throughput. In this paper we quantify the performance of one-sided and two-sided communication paradigms with respect to: 1) the optimal available hardware transfer mechanism, 2) message ordering constraints, 3) per node and per core message concurrency. In addition to using Cray native communication APIs, we use UPC and MPI micro-benchmarks to capture one- and two-sided semantics respectively. Our results indicate that relaxing the message delivery order can improve performance up to 4.6x when compared with strict ordering. When hardware allows it, high-level one-sided programmingmore » models can already take advantage of message reordering. Enforcing the ordering semantics of two-sided communication comes with a performance penalty. Furthermore, we argue that exposing out-of-order delivery at the application level is required for the next-generation programming models. Any ordering constraints in the language specifications reduce communication performance for small messages and increase the number of active cores required for peak throughput.« less

A serial mediation model of message framing on intentions to receive the human papillomavirus (HPV) vaccine: revisiting the role of threat and efficacy perceptions.

PubMed

Krieger, Janice L; Sarge, Melanie A

2013-01-01

Previous research has yielded mixed findings regarding the potential for message framing to influence HPV vaccine-related intentions. Drawing on the Extended Parallel Process Model (EPPM), the current study focuses on the role of threat and efficacy as serial mediators linking message framing and HPV vaccine-related intentions. College-age females and their parents participated in a between-subjects, posttest only experiment to investigate whether behavioral intentions to talk to a doctor about the HPV vaccine differ as a function of framing messages in terms of disease prevention. For young women, framing messages as preventing genital warts (as compared to cancer prevention) significantly increased perceptions of self-efficacy, which enhanced response efficacy perceptions that, in turn, increased intentions to talk to a doctor about the HPV vaccine. There were no effects of message framing among parents. However, response efficacy was a significant mediator of self-efficacy and behavioral intentions for both the college-age females and their parents. The results of this study suggest new approaches for considering the relationship among EPPM constructs.

Real Time Assessment of Young Adults' Attitudes toward Tobacco Messages.

PubMed

Hébert, Emily T; Vandewater, Elizabeth A; Businelle, Michael S; Harrell, Melissa B; Kelder, Steven H; Perry, Cheryl L

2018-01-01

We used ecological momentary assessment (EMA) to examine young adults' attitudes towards pro-tobacco messages encountered in real time and their association with intentions to use tobacco. Young adults (N = 92, ages 18-29) recorded sightings of marketing or social media related to tobacco in real time via mobile app for 28 days. Participants reported message characteristics, their attitudes towards the message, and intentions to use the depicted product for each submission. We used generalized linear mixed models to examine factors related to attitude towards message and intentions to use tobacco. Messages depicting e-cigarettes (p < .001) or hookah (p < .05) were associated with significantly more favorable attitudes compared with traditional cigarettes. Positive attitude towards the message was significantly associated with intention to use the depicted product (p < .001). Messages depicting e-cigarettes and hookah were significantly associated with higher intention to use. Message source was not significantly related to attitudes towards the message or product use intentions. Marketing featuring e-cigarettes and hookah is an important target for future regulation. Given that pro-tobacco and e-cigarette messages are prevalent online, future research should consider the Internet and social media as important venues for counter-marketing and intervention efforts.

Model of epidemic control based on quarantine and message delivery

NASA Astrophysics Data System (ADS)

Wang, Xingyuan; Zhao, Tianfang; Qin, Xiaomeng

2016-09-01

The model provides two novel strategies for the preventive control of epidemic diseases. One approach is related to the different isolating rates in latent period and invasion period. Experiments show that the increasing of isolating rates in invasion period, as long as over 0.5, contributes little to the preventing of epidemic; the improvement of isolation rate in latent period is key to control the disease spreading. Another is a specific mechanism of message delivering and forwarding. Information quality and information accumulating process are also considered there. Macroscopically, diseases are easy to control as long as the immune messages reach a certain quality. Individually, the accumulating messages bring people with certain immunity to the disease. Also, the model is performed on the classic complex networks like scale-free network and small-world network, and location-based social networks. Results show that the proposed measures demonstrate superior performance and significantly reduce the negative impact of epidemic disease.

Implementation of a Parallel Kalman Filter for Stratospheric Chemical Tracer Assimilation

NASA Technical Reports Server (NTRS)

Chang, Lang-Ping; Lyster, Peter M.; Menard, R.; Cohn, S. E.

1998-01-01

A Kalman filter for the assimilation of long-lived atmospheric chemical constituents has been developed for two-dimensional transport models on isentropic surfaces over the globe. An important attribute of the Kalman filter is that it calculates error covariances of the constituent fields using the tracer dynamics. Consequently, the current Kalman-filter assimilation is a five-dimensional problem (coordinates of two points and time), and it can only be handled on computers with large memory and high floating point speed. In this paper, an implementation of the Kalman filter for distributed-memory, message-passing parallel computers is discussed. Two approaches were studied: an operator decomposition and a covariance decomposition. The latter was found to be more scalable than the former, and it possesses the property that the dynamical model does not need to be parallelized, which is of considerable practical advantage. This code is currently used to assimilate constituent data retrieved by limb sounders on the Upper Atmosphere Research Satellite. Tests of the code examined the variance transport and observability properties. Aspects of the parallel implementation, some timing results, and a brief discussion of the physical results will be presented.

Non-exercise Estimation of V02max Using a Dichotomy of Meeting or Not Meeting DHHS Physical Activity Recommendations

NASA Technical Reports Server (NTRS)

Wier, Larry T.; Jackson, Allen W.; Jackson, Andrew S.

2009-01-01

The physical activity guidelines (PAG) established by the US Dept. of Health and Human Services in 2008 is consistent with a rating of >/= 6 on the 11-point NASA Physical Activity Status Scale (PASS). Wier, et. al. developed non-exercise models for estimating VO2(sub max) from a combination of PASS, age, gender and either waist girth (WG) (R = 0.810, SEE= 4.799 ml/kg/min), %Fat (R = 0. 817, SEE = 4.716 ml/kg/min) or BMI (R = 0.802, SEE = 4.900 ml . kg-1. min -1 ). PURPOSE: to develop non-exercise models to estimate VO2max from age, gender, body composition (WG, %Fat, BMI) and PASS dichotomized at meets or does not meet the PAG (PAG-PASS), and to compare the accuracy of the PAG-PASS models with the models using the 11-point PASS. METHODS: 2417 men and 384 women were measured for VO2max by indirect calorimetry (RER >1.1); age (yr), gender by M = 1, W = 0; WG at the umbilicus; %fat by skin-folds, BMI by weight (kg) divided by height squared (m 2 ) , and PAGPASS by PASS < 6 = 0 and =/> 6 = 1. RESULTS: Three models were developed by multiple regression to estimate VO2(sub max) from age, gender, PAG-PASS and either WG (R = 0.790, SEE=5.019 ml/kg/min), %FAT (R= 0.080, SEE = 4.915 ml/kg/min) or BMI (R = 0.777, SEE = 5.162ml/kg/min). Cross-validation by the PRESS technique confirmed these statistics. Simple correlations between measured VO2(sub max) and estimates from the PAG-PASS models with WG, %Fat and BMI were 0.790, 0.800 and 0.777, minimally different from the correlations obtained with the PASS models (0.810, 0.810, and 0.802). PAG-PASS and PASS model constant errors were also similar: < 1 ml/kg/min for subsamples of age, gender, PASS and for VO2(sub max) between 30 and 50 ml/kg/min (70% of the sample) but > 1 ml/kg/min for VO2(sub max) <30 and >50 ml/kg/min. CONCLUSIONS: Non-exercise models using the combined effects of age, gender, body composition and the dichotomized PAG-PASS provide estimates of VO2(sub max) that are accurate for most adults, and the accuracy of these models are similar to previously published models using the 11-point PASS.

Optimizing spread dynamics on graphs by message passing

NASA Astrophysics Data System (ADS)

Altarelli, F.; Braunstein, A.; Dall'Asta, L.; Zecchina, R.

2013-09-01

Cascade processes are responsible for many important phenomena in natural and social sciences. Simple models of irreversible dynamics on graphs, in which nodes activate depending on the state of their neighbors, have been successfully applied to describe cascades in a large variety of contexts. Over the past decades, much effort has been devoted to understanding the typical behavior of the cascades arising from initial conditions extracted at random from some given ensemble. However, the problem of optimizing the trajectory of the system, i.e. of identifying appropriate initial conditions to maximize (or minimize) the final number of active nodes, is still considered to be practically intractable, with the only exception being models that satisfy a sort of diminishing returns property called submodularity. Submodular models can be approximately solved by means of greedy strategies, but by definition they lack cooperative characteristics which are fundamental in many real systems. Here we introduce an efficient algorithm based on statistical physics for the optimization of trajectories in cascade processes on graphs. We show that for a wide class of irreversible dynamics, even in the absence of submodularity, the spread optimization problem can be solved efficiently on large networks. Analytic and algorithmic results on random graphs are complemented by the solution of the spread maximization problem on a real-world network (the Epinions consumer reviews network).

Xyce parallel electronic simulator users guide, version 6.1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keiter, Eric R; Mei, Ting; Russo, Thomas V.

This manual describes the use of the Xyce Parallel Electronic Simulator. Xyce has been designed as a SPICE-compatible, high-performance analog circuit simulator, and has been written to support the simulation needs of the Sandia National Laboratories electrical designers. This development has focused on improving capability over the current state-of-the-art in the following areas; Capability to solve extremely large circuit problems by supporting large-scale parallel computing platforms (up to thousands of processors). This includes support for most popular parallel and serial computers; A differential-algebraic-equation (DAE) formulation, which better isolates the device model package from solver algorithms. This allows one to developmore » new types of analysis without requiring the implementation of analysis-specific device models; Device models that are specifically tailored to meet Sandia's needs, including some radiationaware devices (for Sandia users only); and Object-oriented code design and implementation using modern coding practices. Xyce is a parallel code in the most general sense of the phrase-a message passing parallel implementation-which allows it to run efficiently a wide range of computing platforms. These include serial, shared-memory and distributed-memory parallel platforms. Attention has been paid to the specific nature of circuit-simulation problems to ensure that optimal parallel efficiency is achieved as the number of processors grows.« less

Xyce parallel electronic simulator users' guide, Version 6.0.1.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keiter, Eric R; Mei, Ting; Russo, Thomas V.

This manual describes the use of the Xyce Parallel Electronic Simulator. Xyce has been designed as a SPICE-compatible, high-performance analog circuit simulator, and has been written to support the simulation needs of the Sandia National Laboratories electrical designers. This development has focused on improving capability over the current state-of-the-art in the following areas: Capability to solve extremely large circuit problems by supporting large-scale parallel computing platforms (up to thousands of processors). This includes support for most popular parallel and serial computers. A differential-algebraic-equation (DAE) formulation, which better isolates the device model package from solver algorithms. This allows one to developmore » new types of analysis without requiring the implementation of analysis-specific device models. Device models that are specifically tailored to meet Sandias needs, including some radiationaware devices (for Sandia users only). Object-oriented code design and implementation using modern coding practices. Xyce is a parallel code in the most general sense of the phrase a message passing parallel implementation which allows it to run efficiently a wide range of computing platforms. These include serial, shared-memory and distributed-memory parallel platforms. Attention has been paid to the specific nature of circuit-simulation problems to ensure that optimal parallel efficiency is achieved as the number of processors grows.« less

Xyce parallel electronic simulator users guide, version 6.0.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keiter, Eric R; Mei, Ting; Russo, Thomas V.

This manual describes the use of the Xyce Parallel Electronic Simulator. Xyce has been designed as a SPICE-compatible, high-performance analog circuit simulator, and has been written to support the simulation needs of the Sandia National Laboratories electrical designers. This development has focused on improving capability over the current state-of-the-art in the following areas: Capability to solve extremely large circuit problems by supporting large-scale parallel computing platforms (up to thousands of processors). This includes support for most popular parallel and serial computers. A differential-algebraic-equation (DAE) formulation, which better isolates the device model package from solver algorithms. This allows one to developmore » new types of analysis without requiring the implementation of analysis-specific device models. Device models that are specifically tailored to meet Sandias needs, including some radiationaware devices (for Sandia users only). Object-oriented code design and implementation using modern coding practices. Xyce is a parallel code in the most general sense of the phrase a message passing parallel implementation which allows it to run efficiently a wide range of computing platforms. These include serial, shared-memory and distributed-memory parallel platforms. Attention has been paid to the specific nature of circuit-simulation problems to ensure that optimal parallel efficiency is achieved as the number of processors grows.« less

Graphical models for optimal power flow

DOE PAGES

Dvijotham, Krishnamurthy; Chertkov, Michael; Van Hentenryck, Pascal; ...

2016-09-13

Optimal power flow (OPF) is the central optimization problem in electric power grids. Although solved routinely in the course of power grid operations, it is known to be strongly NP-hard in general, and weakly NP-hard over tree networks. In this paper, we formulate the optimal power flow problem over tree networks as an inference problem over a tree-structured graphical model where the nodal variables are low-dimensional vectors. We adapt the standard dynamic programming algorithm for inference over a tree-structured graphical model to the OPF problem. Combining this with an interval discretization of the nodal variables, we develop an approximation algorithmmore » for the OPF problem. Further, we use techniques from constraint programming (CP) to perform interval computations and adaptive bound propagation to obtain practically efficient algorithms. Compared to previous algorithms that solve OPF with optimality guarantees using convex relaxations, our approach is able to work for arbitrary tree-structured distribution networks and handle mixed-integer optimization problems. Further, it can be implemented in a distributed message-passing fashion that is scalable and is suitable for “smart grid” applications like control of distributed energy resources. In conclusion, numerical evaluations on several benchmark networks show that practical OPF problems can be solved effectively using this approach.« less

Mobile phone text message reminders: Measuring preferences of people with antipsychotic medication.

PubMed

Kauppi, Kaisa; Kannisto, Kati A; Hätönen, Heli; Anttila, Minna; Löyttyniemi, Eliisa; Adams, Clive E; Välimäki, Maritta

2015-10-01

Mobile technology use, including Short Messaging Service (SMS) text messaging, has increased in health care services. Preferences regarding the type or timing of text messages sent by healthcare providers to people with antipsychotic medication have not yet been fully investigated. This study examines the relationship between patients' demographic characteristics and the tailored messages they select. The study ("Mobile.Net", 27704027) includes a structured analysis of a random sub-sample of participants who received messages for 12months. The data were collected in 24 sites and 45 psychiatric hospitals in Finland and analyzed with descriptive statistics and Poisson regression models. The study sample involved 562 people on antipsychotic medication, and a total of 2112 text messages (2 to 25 monthly) were analysed. Regarding message content, there was no significant variation in the proportions relating to 'medication', 'treatment appointments' or 'free time'. Monday was the most popular day to receive messages and morning was preferred to later in the day. Age was most closely associated with 'number of messages' and 'time of messages'. Older women and younger men preferred higher numbers of messages (p=0.0031). Participants preferred positive, encouraging and slightly humorous messages. The findings suggest that messages may be acceptable for difficult to access groups in follow-up. This type of intervention may be useful for various types of patients especially for younger males. To further support the evidence about factors related to message utilization and use, it is important to evaluate the effectiveness of text messages in psychiatric care. Copyright © 2015. Published by Elsevier B.V.

On the delay analysis of a TDMA channel with finite buffer capacity

NASA Technical Reports Server (NTRS)

Yan, T.-Y.

1982-01-01

The throughput performance of a TDMA channel with finite buffer capacity for transmitting data messages is considered. Each station has limited message buffer capacity and has Poisson message arrivals. Message arrivals will be blocked if the buffers are congested. Using the embedded Markov chain model, the solution procedure for the limiting system-size probabilities is presented in a recursive fashion. Numerical examples are given to demonstrate the tradeoffs between the blocking probabilities and the buffer sizing strategy.

3D unstructured-mesh radiation transport codes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morel, J.

1997-12-31

Three unstructured-mesh radiation transport codes are currently being developed at Los Alamos National Laboratory. The first code is ATTILA, which uses an unstructured tetrahedral mesh in conjunction with standard Sn (discrete-ordinates) angular discretization, standard multigroup energy discretization, and linear-discontinuous spatial differencing. ATTILA solves the standard first-order form of the transport equation using source iteration in conjunction with diffusion-synthetic acceleration of the within-group source iterations. DANTE is designed to run primarily on workstations. The second code is DANTE, which uses a hybrid finite-element mesh consisting of arbitrary combinations of hexahedra, wedges, pyramids, and tetrahedra. DANTE solves several second-order self-adjoint forms of the transport equation including the even-parity equation, the odd-parity equation, and a new equation called the self-adjoint angular flux equation. DANTE also offers three angular discretization options:more » $$S{_}n$$ (discrete-ordinates), $$P{_}n$$ (spherical harmonics), and $$SP{_}n$$ (simplified spherical harmonics). DANTE is designed to run primarily on massively parallel message-passing machines, such as the ASCI-Blue machines at LANL and LLNL. The third code is PERICLES, which uses the same hybrid finite-element mesh as DANTE, but solves the standard first-order form of the transport equation rather than a second-order self-adjoint form. DANTE uses a standard $$S{_}n$$ discretization in angle in conjunction with trilinear-discontinuous spatial differencing, and diffusion-synthetic acceleration of the within-group source iterations. PERICLES was initially designed to run on workstations, but a version for massively parallel message-passing machines will be built. The three codes will be described in detail and computational results will be presented.« less

Parallel definition of tear film maps on distributed-memory clusters for the support of dry eye diagnosis.

PubMed

González-Domínguez, Jorge; Remeseiro, Beatriz; Martín, María J

2017-02-01

The analysis of the interference patterns on the tear film lipid layer is a useful clinical test to diagnose dry eye syndrome. This task can be automated with a high degree of accuracy by means of the use of tear film maps. However, the time required by the existing applications to generate them prevents a wider acceptance of this method by medical experts. Multithreading has been previously successfully employed by the authors to accelerate the tear film map definition on multicore single-node machines. In this work, we propose a hybrid message-passing and multithreading parallel approach that further accelerates the generation of tear film maps by exploiting the computational capabilities of distributed-memory systems such as multicore clusters and supercomputers. The algorithm for drawing tear film maps is parallelized using Message Passing Interface (MPI) for inter-node communications and the multithreading support available in the C++11 standard for intra-node parallelization. The original algorithm is modified to reduce the communications and increase the scalability. The hybrid method has been tested on 32 nodes of an Intel cluster (with two 12-core Haswell 2680v3 processors per node) using 50 representative images. Results show that maximum runtime is reduced from almost two minutes using the previous only-multithreaded approach to less than ten seconds using the hybrid method. The hybrid MPI/multithreaded implementation can be used by medical experts to obtain tear film maps in only a few seconds, which will significantly accelerate and facilitate the diagnosis of the dry eye syndrome. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

A Multi-Level Parallelization Concept for High-Fidelity Multi-Block Solvers

NASA Technical Reports Server (NTRS)

Hatay, Ferhat F.; Jespersen, Dennis C.; Guruswamy, Guru P.; Rizk, Yehia M.; Byun, Chansup; Gee, Ken; VanDalsem, William R. (Technical Monitor)

1997-01-01

The integration of high-fidelity Computational Fluid Dynamics (CFD) analysis tools with the industrial design process benefits greatly from the robust implementations that are transportable across a wide range of computer architectures. In the present work, a hybrid domain-decomposition and parallelization concept was developed and implemented into the widely-used NASA multi-block Computational Fluid Dynamics (CFD) packages implemented in ENSAERO and OVERFLOW. The new parallel solver concept, PENS (Parallel Euler Navier-Stokes Solver), employs both fine and coarse granularity in data partitioning as well as data coalescing to obtain the desired load-balance characteristics on the available computer platforms. This multi-level parallelism implementation itself introduces no changes to the numerical results, hence the original fidelity of the packages are identically preserved. The present implementation uses the Message Passing Interface (MPI) library for interprocessor message passing and memory accessing. By choosing an appropriate combination of the available partitioning and coalescing capabilities only during the execution stage, the PENS solver becomes adaptable to different computer architectures from shared-memory to distributed-memory platforms with varying degrees of parallelism. The PENS implementation on the IBM SP2 distributed memory environment at the NASA Ames Research Center obtains 85 percent scalable parallel performance using fine-grain partitioning of single-block CFD domains using up to 128 wide computational nodes. Multi-block CFD simulations of complete aircraft simulations achieve 75 percent perfect load-balanced executions using data coalescing and the two levels of parallelism. SGI PowerChallenge, SGI Origin 2000, and a cluster of workstations are the other platforms where the robustness of the implementation is tested. The performance behavior on the other computer platforms with a variety of realistic problems will be included as this on-going study progresses.

Message passing interface and multithreading hybrid for parallel molecular docking of large databases on petascale high performance computing machines.

PubMed

Zhang, Xiaohua; Wong, Sergio E; Lightstone, Felice C

2013-04-30

A mixed parallel scheme that combines message passing interface (MPI) and multithreading was implemented in the AutoDock Vina molecular docking program. The resulting program, named VinaLC, was tested on the petascale high performance computing (HPC) machines at Lawrence Livermore National Laboratory. To exploit the typical cluster-type supercomputers, thousands of docking calculations were dispatched by the master process to run simultaneously on thousands of slave processes, where each docking calculation takes one slave process on one node, and within the node each docking calculation runs via multithreading on multiple CPU cores and shared memory. Input and output of the program and the data handling within the program were carefully designed to deal with large databases and ultimately achieve HPC on a large number of CPU cores. Parallel performance analysis of the VinaLC program shows that the code scales up to more than 15K CPUs with a very low overhead cost of 3.94%. One million flexible compound docking calculations took only 1.4 h to finish on about 15K CPUs. The docking accuracy of VinaLC has been validated against the DUD data set by the re-docking of X-ray ligands and an enrichment study, 64.4% of the top scoring poses have RMSD values under 2.0 Å. The program has been demonstrated to have good enrichment performance on 70% of the targets in the DUD data set. An analysis of the enrichment factors calculated at various percentages of the screening database indicates VinaLC has very good early recovery of actives. Copyright © 2013 Wiley Periodicals, Inc.

The Prodiguer Messaging Platform

NASA Astrophysics Data System (ADS)

Denvil, S.; Greenslade, M. A.; Carenton, N.; Levavasseur, G.; Raciazek, J.

2015-12-01

CONVERGENCE is a French multi-partner national project designed to gather HPC and informatics expertise to innovate in the context of running French global climate models with differing grids and at differing resolutions. Efficient and reliable execution of these models and the management and dissemination of model output are some of the complexities that CONVERGENCE aims to resolve.At any one moment in time, researchers affiliated with the Institut Pierre Simon Laplace (IPSL) climate modeling group, are running hundreds of global climate simulations. These simulations execute upon a heterogeneous set of French High Performance Computing (HPC) environments. The IPSL's simulation execution runtime libIGCM (library for IPSL Global Climate Modeling group) has recently been enhanced so as to support hitherto impossible realtime use cases such as simulation monitoring, data publication, metrics collection, simulation control, visualizations … etc. At the core of this enhancement is Prodiguer: an AMQP (Advanced Message Queue Protocol) based event driven asynchronous distributed messaging platform. libIGCM now dispatches copious amounts of information, in the form of messages, to the platform for remote processing by Prodiguer software agents at IPSL servers in Paris. Such processing takes several forms: Persisting message content to database(s); Launching rollback jobs upon simulation failure; Notifying downstream applications; Automation of visualization pipelines; We will describe and/or demonstrate the platform's: Technical implementation; Inherent ease of scalability; Inherent adaptiveness in respect to supervising simulations; Web portal receiving simulation notifications in realtime.

The Stages of Change Model: An Effective Audience Analysis Tool Used To Design and Implement Health Promoting Messages.

ERIC Educational Resources Information Center

Smith, Ronda L.

Researchers have been slow to acknowledge the salient role communication can play in motivating people to adopt more healthy lifestyles. Because persuasive messages increase awareness and can increase health promoting behaviors, it is important to determine the most effective health promoting messages in various health contexts. Thus, the primary…

Django Remote Submission

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doucet, Mathieu; Hobson, Tanner C.; Ferraz Leal, Ricardo Miguel

The Django Remote Submission (DRS) is a Django (Django, n.d.) application to manage long running job submission, including starting the job, saving logs, and storing results. It is an independent project available as a standalone pypi package (PyPi, n.d.). It can be easily integrated in any Django project. The source code is freely available as a GitHub repository (django-remote-submission, n.d.). To run the jobs in background, DRS takes advantage of Celery (Celery, n.d.), a powerful asynchronous job queue used for running tasks in the background, and the Redis Server (Redis, n.d.), an in-memory data structure store. Celery uses brokers tomore » pass messages between a Django Project and the Celery workers. Redis is the message broker of DRS. In addition DRS provides real time monitoring of the progress of Jobs and associated logs. Through the Django Channels project (Channels, n.d.), and the usage of Web Sockets, it is possible to asynchronously display the Job Status and the live Job output (standard output and standard error) on a web page.« less

HYDRA : High-speed simulation architecture for precision spacecraft formation simulation

NASA Technical Reports Server (NTRS)

Martin, Bryan J.; Sohl, Garett.

2003-01-01

e Hierarchical Distributed Reconfigurable Architecture- is a scalable simulation architecture that provides flexibility and ease-of-use which take advantage of modern computation and communication hardware. It also provides the ability to implement distributed - or workstation - based simulations and high-fidelity real-time simulation from a common core. Originally designed to serve as a research platform for examining fundamental challenges in formation flying simulation for future space missions, it is also finding use in other missions and applications, all of which can take advantage of the underlying Object-Oriented structure to easily produce distributed simulations. Hydra automates the process of connecting disparate simulation components (Hydra Clients) through a client server architecture that uses high-level descriptions of data associated with each client to find and forge desirable connections (Hydra Services) at run time. Services communicate through the use of Connectors, which abstract messaging to provide single-interface access to any desired communication protocol, such as from shared-memory message passing to TCP/IP to ACE and COBRA. Hydra shares many features with the HLA, although providing more flexibility in connectivity services and behavior overriding.

Research for the design of visual fatigue based on the computer visual communication

NASA Astrophysics Data System (ADS)

Deng, Hu-Bin; Ding, Bao-min

2013-03-01

With the era of rapid development of computer networks. The role of network communication in the social, economic, political, become more and more important and suggested their special role. The computer network communicat ion through the modern media and byway of the visual communication effect the public of the emotional, spiritual, career and other aspects of the life. While its rapid growth also brought some problems, It is that their message across to the public, its design did not pass a relat ively perfect manifestation to express the informat ion. So this not only leads to convey the error message, but also to cause the physical and psychological fatigue for the audiences. It is said that the visual fatigue. In order to reduce the fatigue when people obtain the useful information in using computer. Let the audience in a short time to obtain the most useful informat ion, this article gave a detailed account of its causes, and propose effective solutions and, through the specific examples to explain it, also in the future computer design visual communicat ion applications development prospect.

Django Remote Submission

DOE PAGES

Doucet, Mathieu; Hobson, Tanner C.; Ferraz Leal, Ricardo Miguel

2017-08-01

The Django Remote Submission (DRS) is a Django (Django, n.d.) application to manage long running job submission, including starting the job, saving logs, and storing results. It is an independent project available as a standalone pypi package (PyPi, n.d.). It can be easily integrated in any Django project. The source code is freely available as a GitHub repository (django-remote-submission, n.d.). To run the jobs in background, DRS takes advantage of Celery (Celery, n.d.), a powerful asynchronous job queue used for running tasks in the background, and the Redis Server (Redis, n.d.), an in-memory data structure store. Celery uses brokers tomore » pass messages between a Django Project and the Celery workers. Redis is the message broker of DRS. In addition DRS provides real time monitoring of the progress of Jobs and associated logs. Through the Django Channels project (Channels, n.d.), and the usage of Web Sockets, it is possible to asynchronously display the Job Status and the live Job output (standard output and standard error) on a web page.« less

Voice-Based Technology for Parent Involvement: Results and Effects.

ERIC Educational Resources Information Center

Bauch, Jerold P.

A study was conducted to implement and evaluate the Transparent School Model for improving parent involvement in nine Indiana schools. The Model uses computer-based voice messaging to exchange information between teachers and parents. Teachers record a brief message for parents that describes what was taught, special learning events, homework…

The effects of message framing within the stages of change on smoking cessation intentions and behaviors.

PubMed

Cornacchione, Jennifer; Smith, Sandi W

2012-01-01

This study examines two commonly used and accepted theoretical models in health communication-the stages of change and message framing-to determine whether gain- or loss-framed messages are more effective at getting people to intend to quit smoking depending on their current stage of change (precontemplation, contemplation, or preparation). One hundred forty-eight current smokers were exposed to one of four gain- or loss-framed messages that emphasized the benefits of cessation or the costs of smoking. Message believability, message processing, and stage movement were measured to see if any differences existed as a function of the individual's base stage of change and message frame exposure. Overall, results indicated that all participants, regardless of stage and frame, engaged in more central than peripheral message processing. However, those in the precontemplation/loss frame and preparation/gain frame conditions engaged in significantly less cognitive processing than those in all other conditions. Additionally, gain-framed messages were most influential at getting individuals to progress from the contemplation to the preparation stage. Implications and future directions for research are also discussed.

Social Interface Model: Theorizing Ecological Post-Delivery Processes for Intervention Effects.

PubMed

Pettigrew, Jonathan; Segrott, Jeremy; Ray, Colter D; Littlecott, Hannah

2018-01-03

Successful prevention programs depend on a complex interplay among aspects of the intervention, the participant, the specific intervention setting, and the broader set of contexts with which a participant interacts. There is a need to theorize what happens as participants bring intervention ideas and behaviors into other life-contexts, and theory has not yet specified how social interactions about interventions may influence outcomes. To address this gap, we use an ecological perspective to develop the social interface model. This paper presents the key components of the model and its potential to aid the design and implementation of prevention interventions. The model is predicated on the idea that intervention message effectiveness depends not only on message aspects but also on the participants' adoption and adaptation of the message vis-à-vis their social ecology. The model depicts processes by which intervention messages are received and enacted by participants through social processes occurring within and between relevant microsystems. Mesosystem interfaces (negligible interface, transference, co-dependence, and interdependence) can facilitate or detract from intervention effects. The social interface model advances prevention science by theorizing that practitioners can create better quality interventions by planning for what occurs after interventions are delivered.

Social media messaging in pregnancy: comparing content of Text4baby to content of free smart phone applications of pregnancy.

PubMed

Lewkowitz, Adam K; O'Donnell, Betsy E; Nakagawa, Sanae; Vargas, Juan E; Zlatnik, Marya G

2016-03-01

Text4baby is the only free text-message program for pregnancy available. Our objective was to determine whether content differed between Text4baby and popular pregnancy smart phone applications (apps). Researchers enrolled in Text4baby in 2012 and downloaded the four most-popular free pregnancy smart phone apps in July 2013; content was re-extracted in February 2014. Messages were assigned thematic codes. Two researchers coded messages independently before reviewing all the codes jointly to ensure consistency. Logistic regression modeling determined statistical differences between Text4baby and smart phone apps. About 1399 messages were delivered. Of these, 333 messages had content related to more than one theme and were coded as such, resulting in 1820 codes analyzed. Compared to smart phone apps, Text4baby was significantly more likely to have content regarding Postpartum Planning, Seeking Care, Recruitment and Prevention and significantly less likely to mention Normal Pregnancy Symptoms. No messaging program included content regarding postpartum contraception. To improve content without increasing text message number, Text4baby could replace messages on recruitment with messages regarding normal pregnancy symptoms, fetal development and postpartum contraception.

The Allure of Privacy or the Desire for Self-Expression? Identifying Users' Gratifications for Ephemeral, Photograph-Based Communication.

PubMed

Waddell, T Franklin

2016-07-01

Temporary messaging programs continue to rise in popularity, due in large part to the perceived privacy that they afford. However, recent controversies have revealed that messages shared on ephemeral messaging services are persistent and potentially retrieval, thus undermining the privacy they are assumed to provide. Given this paradox, why are temporary messaging services so popular? Does the allure of privacy still motivate the use of temporary messaging programs? Or, if privacy is no longer afforded by ephemeral messaging, what other psychological gratifications do these applications fulfill that might account for their continued use? Informed by the Modality-Agency-Interactivity-Navigability (MAIN) model and the uses and gratifications tradition, the current study conducted qualitative interviews to identify the gratifications that individuals derive from the popular ephemeral messaging application, Snapchat. Study results show that the visual affordances of ephemeral messaging have legitimized photographic communication, providing self-expression and relational gratifications that are unfulfilled by text-based applications. By comparison, users report low levels of trust in the privacy affordances of ephemeral messaging, and instead projecting negative effects of temporary messaging on other users rather than self. Theoretical and practical implications of these results are discussed.

Effect of Message Format and Content on Attitude Accessibility Regarding Sexually Transmitted Infections.

PubMed

Jain, Parul; Hoffman, Eric; Beam, Michael; Xu, Shan Susan

2017-11-01

Sexually transmitted infections (STIs) are widespread in the United States among people ages 15-24 years and cost almost $16 billion yearly. It is therefore important to understand message design strategies that could help reduce these numbers. Guided by exemplification theory and the extended parallel process model (EPPM), this study examines the influence of message format and the presence versus absence of a graphic image on recipients' accessibility of STI attitudes regarding safe sex. Results of the experiment indicate a significant effect from testimonial messages on increased attitude accessibility regarding STIs compared to statistical messages. Results also indicate a conditional indirect effect of testimonial messages on STI attitude accessibility, though threat is greater when a graphic image is included. Implications and directions for future research are discussed.

Applying a Cognitive-Affective Model of Conceptual Change to Professional Development

NASA Astrophysics Data System (ADS)

Ebert, Ellen K.; Crippen, Kent J.

2010-04-01

This study evaluated Gregoire’s (2003) Cognitive-Affective Conceptual Change model (CAMCC) for predicting and assessing conceptual change in science teachers engaged in a long-term professional development project set in a large school district in the southwestern United States. A multiple case study method with data from three teacher participants was used to understand the process of integrating and applying a reform message of inquiry based science teaching. Data sources included: responses to example teaching scenarios, reflective essays, lesson plans, classroom observations, and action research projects. Findings show that the CAMCC functioned well in predicting how these teachers made decisions that impacted how they processed the reform message. When the reform message was communicated in such a way as to initiate stress appraisal, conceptual change occurred, producing changes in classroom practice. If the reform message did not initiate stress appraisal, teachers rejected the professional development message and developed heuristic responses. In order to further research and improve practice, propositions for assessments related to the CAMCC are provided.

Testing a social cognitive theory-based model of indoor tanning: implications for skin cancer prevention messages.

PubMed

Noar, Seth M; Myrick, Jessica Gall; Zeitany, Alexandra; Kelley, Dannielle; Morales-Pico, Brenda; Thomas, Nancy E

2015-01-01

The lack of a theory-based understanding of indoor tanning is a major impediment to the development of effective messages to prevent or reduce this behavior. This study applied the Comprehensive Indoor Tanning Expectations (CITE) scale in an analysis of indoor tanning behavior among sorority women (total N = 775). Confirmatory factor analyses indicated that CITE positive and negative expectations were robust, multidimensional factors and that a hierarchical structure fit the data well. Social cognitive theory-based structural equation models demonstrated that appearance-oriented variables were significantly associated with outcome expectations. Outcome expectations were, in turn, significantly associated with temptations to tan, intention to tan indoors, and indoor tanning behavior. The implications of these findings for the development of messages to prevent and reduce indoor tanning behavior are discussed in two domains: (a) messages that attempt to change broader societal perceptions about tan skin, and (b) messages that focus more narrowly on indoor tanning-challenging positive expectations, enhancing negative expectations, and encouraging substitution of sunless tanning products.