A simple GPU-accelerated two-dimensional MUSCL-Hancock solver for ideal magnetohydrodynamics

NASA Astrophysics Data System (ADS)

Bard, Christopher M.; Dorelli, John C.

2014-02-01

We describe our experience using NVIDIA's CUDA (Compute Unified Device Architecture) C programming environment to implement a two-dimensional second-order MUSCL-Hancock ideal magnetohydrodynamics (MHD) solver on a GTX 480 Graphics Processing Unit (GPU). Taking a simple approach in which the MHD variables are stored exclusively in the global memory of the GTX 480 and accessed in a cache-friendly manner (without further optimizing memory access by, for example, staging data in the GPU's faster shared memory), we achieved a maximum speed-up of ≈126 for a 10242 grid relative to the sequential C code running on a single Intel Nehalem (2.8 GHz) core. This speedup is consistent with simple estimates based on the known floating point performance, memory throughput and parallel processing capacity of the GTX 480.

Performing an allreduce operation using shared memory

DOEpatents

Archer, Charles J [Rochester, MN; Dozsa, Gabor [Ardsley, NY; Ratterman, Joseph D [Rochester, MN; Smith, Brian E [Rochester, MN

2012-04-17

Methods, apparatus, and products are disclosed for performing an allreduce operation using shared memory that include: receiving, by at least one of a plurality of processing cores on a compute node, an instruction to perform an allreduce operation; establishing, by the core that received the instruction, a job status object for specifying a plurality of shared memory allreduce work units, the plurality of shared memory allreduce work units together performing the allreduce operation on the compute node; determining, by an available core on the compute node, a next shared memory allreduce work unit in the job status object; and performing, by that available core on the compute node, that next shared memory allreduce work unit.

Performing an allreduce operation using shared memory

DOEpatents

Archer, Charles J; Dozsa, Gabor; Ratterman, Joseph D; Smith, Brian E

2014-06-10

Methods, apparatus, and products are disclosed for performing an allreduce operation using shared memory that include: receiving, by at least one of a plurality of processing cores on a compute node, an instruction to perform an allreduce operation; establishing, by the core that received the instruction, a job status object for specifying a plurality of shared memory allreduce work units, the plurality of shared memory allreduce work units together performing the allreduce operation on the compute node; determining, by an available core on the compute node, a next shared memory allreduce work unit in the job status object; and performing, by that available core on the compute node, that next shared memory allreduce work unit.

Efficient Numeric and Geometric Computations using Heterogeneous Shared Memory Architectures

DTIC Science & Technology

2017-10-04

Report: Efficient Numeric and Geometric Computations using Heterogeneous Shared Memory Architectures The views, opinions and/or findings contained in this...Chapel Hill Title: Efficient Numeric and Geometric Computations using Heterogeneous Shared Memory Architectures Report Term: 0-Other Email: dm...algorithms for scientific and geometric computing by exploiting the power and performance efficiency of heterogeneous shared memory architectures . These

The effect of the order in which episodic autobiographical memories versus autobiographical knowledge are shared on feelings of closeness.

PubMed

Brandon, Nicole R; Beike, Denise R; Cole, Holly E

2017-07-01

Autobiographical memories (AMs) can be used to create and maintain closeness with others [Alea, N., & Bluck, S. (2003). Why are you telling me that? A conceptual model of the social function of autobiographical memory. Memory, 11(2), 165-178]. However, the differential effects of memory specificity are not well established. Two studies with 148 participants tested whether the order in which autobiographical knowledge (AK) and specific episodic AM (EAM) are shared affects feelings of closeness. Participants read two memories hypothetically shared by each of four strangers. The strangers first shared either AK or an EAM, and then shared either AK or an EAM. Participants were randomly assigned to read either positive or negative AMs from the strangers. Findings suggest that people feel closer to those who share positive AMs in the same way they construct memories: starting with general and moving to specific.

A Simple GPU-Accelerated Two-Dimensional MUSCL-Hancock Solver for Ideal Magnetohydrodynamics

NASA Technical Reports Server (NTRS)

Bard, Christopher; Dorelli, John C.

2013-01-01

We describe our experience using NVIDIA's CUDA (Compute Unified Device Architecture) C programming environment to implement a two-dimensional second-order MUSCL-Hancock ideal magnetohydrodynamics (MHD) solver on a GTX 480 Graphics Processing Unit (GPU). Taking a simple approach in which the MHD variables are stored exclusively in the global memory of the GTX 480 and accessed in a cache-friendly manner (without further optimizing memory access by, for example, staging data in the GPU's faster shared memory), we achieved a maximum speed-up of approx. = 126 for a sq 1024 grid relative to the sequential C code running on a single Intel Nehalem (2.8 GHz) core. This speedup is consistent with simple estimates based on the known floating point performance, memory throughput and parallel processing capacity of the GTX 480.

Multiprocessor architecture: Synthesis and evaluation

NASA Technical Reports Server (NTRS)

Standley, Hilda M.

1990-01-01

Multiprocessor computed architecture evaluation for structural computations is the focus of the research effort described. Results obtained are expected to lead to more efficient use of existing architectures and to suggest designs for new, application specific, architectures. The brief descriptions given outline a number of related efforts directed toward this purpose. The difficulty is analyzing an existing architecture or in designing a new computer architecture lies in the fact that the performance of a particular architecture, within the context of a given application, is determined by a number of factors. These include, but are not limited to, the efficiency of the computation algorithm, the programming language and support environment, the quality of the program written in the programming language, the multiplicity of the processing elements, the characteristics of the individual processing elements, the interconnection network connecting processors and non-local memories, and the shared memory organization covering the spectrum from no shared memory (all local memory) to one global access memory. These performance determiners may be loosely classified as being software or hardware related. This distinction is not clear or even appropriate in many cases. The effect of the choice of algorithm is ignored by assuming that the algorithm is specified as given. Effort directed toward the removal of the effect of the programming language and program resulted in the design of a high-level parallel programming language. Two characteristics of the fundamental structure of the architecture (memory organization and interconnection network) are examined.

Distributed shared memory for roaming large volumes.

PubMed

Castanié, Laurent; Mion, Christophe; Cavin, Xavier; Lévy, Bruno

2006-01-01

We present a cluster-based volume rendering system for roaming very large volumes. This system allows to move a gigabyte-sized probe inside a total volume of several tens or hundreds of gigabytes in real-time. While the size of the probe is limited by the total amount of texture memory on the cluster, the size of the total data set has no theoretical limit. The cluster is used as a distributed graphics processing unit that both aggregates graphics power and graphics memory. A hardware-accelerated volume renderer runs in parallel on the cluster nodes and the final image compositing is implemented using a pipelined sort-last rendering algorithm. Meanwhile, volume bricking and volume paging allow efficient data caching. On each rendering node, a distributed hierarchical cache system implements a global software-based distributed shared memory on the cluster. In case of a cache miss, this system first checks page residency on the other cluster nodes instead of directly accessing local disks. Using two Gigabit Ethernet network interfaces per node, we accelerate data fetching by a factor of 4 compared to directly accessing local disks. The system also implements asynchronous disk access and texture loading, which makes it possible to overlap data loading, volume slicing and rendering for optimal volume roaming.

Shared Semantics and the Use of Organizational Memories for E-Mail Communications.

ERIC Educational Resources Information Center

Schwartz, David G.

1998-01-01

Examines the use of shared semantics information to link concepts in an organizational memory to e-mail communications. Presents a framework for determining shared semantics based on organizational and personal user profiles. Illustrates how shared semantics are used by the HyperMail system to help link organizational memories (OM) content to…

Work stealing for GPU-accelerated parallel programs in a global address space framework: WORK STEALING ON GPU-ACCELERATED SYSTEMS

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

Arafat, Humayun; Dinan, James; Krishnamoorthy, Sriram

Task parallelism is an attractive approach to automatically load balance the computation in a parallel system and adapt to dynamism exhibited by parallel systems. Exploiting task parallelism through work stealing has been extensively studied in shared and distributed-memory contexts. In this paper, we study the design of a system that uses work stealing for dynamic load balancing of task-parallel programs executed on hybrid distributed-memory CPU-graphics processing unit (GPU) systems in a global-address space framework. We take into account the unique nature of the accelerator model employed by GPUs, the significant performance difference between GPU and CPU execution as a functionmore » of problem size, and the distinct CPU and GPU memory domains. We consider various alternatives in designing a distributed work stealing algorithm for CPU-GPU systems, while taking into account the impact of task distribution and data movement overheads. These strategies are evaluated using microbenchmarks that capture various execution configurations as well as the state-of-the-art CCSD(T) application module from the computational chemistry domain.« less

Work stealing for GPU-accelerated parallel programs in a global address space framework

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

Arafat, Humayun; Dinan, James; Krishnamoorthy, Sriram

Task parallelism is an attractive approach to automatically load balance the computation in a parallel system and adapt to dynamism exhibited by parallel systems. Exploiting task parallelism through work stealing has been extensively studied in shared and distributed-memory contexts. In this paper, we study the design of a system that uses work stealing for dynamic load balancing of task-parallel programs executed on hybrid distributed-memory CPU-graphics processing unit (GPU) systems in a global-address space framework. We take into account the unique nature of the accelerator model employed by GPUs, the significant performance difference between GPU and CPU execution as a functionmore » of problem size, and the distinct CPU and GPU memory domains. We consider various alternatives in designing a distributed work stealing algorithm for CPU-GPU systems, while taking into account the impact of task distribution and data movement overheads. These strategies are evaluated using microbenchmarks that capture various execution configurations as well as the state-of-the-art CCSD(T) application module from the computational chemistry domain« less

Exploring Manycore Multinode Systems for Irregular Applications with FPGA Prototyping

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

Ceriani, Marco; Palermo, Gianluca; Secchi, Simone

We present a prototype of a multi-core architecture implemented on FPGA, designed to enable efficient execution of irregular applications on distributed shared memory machines, while maintaining high performance on regular workloads. The architecture is composed of off-the-shelf soft-core cores, local interconnection and memory interface, integrated with custom components that optimize it for irregular applications. It relies on three key elements: a global address space, multithreading, and fine-grained synchronization. Global addresses are scrambled to reduce the formation of network hot-spots, while the latency of the transactions is covered by integrating an hardware scheduler within the custom load/store buffers to take advantagemore » from the availability of multiple executions threads, increasing the efficiency in a transparent way to the application. We evaluated a dual node system irregular kernels showing scalability in the number of cores and threads.« less

Sovereignty transformed: a sociology of human rights.

PubMed

Levy, Daniel; Sznaider, Natan

2006-12-01

This paper examines how global interdependencies and the consolidation of a human rights discourse are transforming national sovereignty. Social researchers frequently address the supremacy of state sovereignty and the absoluteness of human rights as mutually exclusive categories. However, rather than presupposing that a universal rights discourse is necessarily leading to the demise of sovereignty, we suggest that an increasingly de-nationalized conception of legitimacy is contributing to a reconfiguration of sovereignty itself. Through the analytic prism of historical memories - which refers to shared understandings specific pasts carry for present concerns of a political community - we provide an explanatory factor for the salience of human rights norms as a globally available repertoire of legitimate claim making. While states retain most of their sovereign functions, their legitimacy is no longer exclusively conditioned by a contract with the nation, but also by their adherence to a set of nation-transcending human rights ideals. Legitimacy is mediated by how willing states are to engage with 'judicial memories' of human rights abuses and their articulation in cosmopolitan legal frames. Empirically, we focus on war crime trials and how legal inscriptions of memories of human rights abuses are recasting the jurisdiction of International Law. The readiness of states to engage with rights abuses is becoming politically and culturally consequential, as adherence to global human rights norms confers legitimacy.

Technical support for digital systems technology development. Task order 1: ISP contention analysis and control

NASA Technical Reports Server (NTRS)

Stehle, Roy H.; Ogier, Richard G.

1993-01-01

Alternatives for realizing a packet-based network switch for use on a frequency division multiple access/time division multiplexed (FDMA/TDM) geostationary communication satellite were investigated. Each of the eight downlink beams supports eight directed dwells. The design needed to accommodate multicast packets with very low probability of loss due to contention. Three switch architectures were designed and analyzed. An output-queued, shared bus system yielded a functionally simple system, utilizing a first-in, first-out (FIFO) memory per downlink dwell, but at the expense of a large total memory requirement. A shared memory architecture offered the most efficiency in memory requirements, requiring about half the memory of the shared bus design. The processing requirement for the shared-memory system adds system complexity that may offset the benefits of the smaller memory. An alternative design using a shared memory buffer per downlink beam decreases circuit complexity through a distributed design, and requires at most 1000 packets of memory more than the completely shared memory design. Modifications to the basic packet switch designs were proposed to accommodate circuit-switched traffic, which must be served on a periodic basis with minimal delay. Methods for dynamically controlling the downlink dwell lengths were developed and analyzed. These methods adapt quickly to changing traffic demands, and do not add significant complexity or cost to the satellite and ground station designs. Methods for reducing the memory requirement by not requiring the satellite to store full packets were also proposed and analyzed. In addition, optimal packet and dwell lengths were computed as functions of memory size for the three switch architectures.

Parallel Computation of the Regional Ocean Modeling System (ROMS)

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

Wang, P; Song, Y T; Chao, Y

2005-04-05

The Regional Ocean Modeling System (ROMS) is a regional ocean general circulation modeling system solving the free surface, hydrostatic, primitive equations over varying topography. It is free software distributed world-wide for studying both complex coastal ocean problems and the basin-to-global scale ocean circulation. The original ROMS code could only be run on shared-memory systems. With the increasing need to simulate larger model domains with finer resolutions and on a variety of computer platforms, there is a need in the ocean-modeling community to have a ROMS code that can be run on any parallel computer ranging from 10 to hundreds ofmore » processors. Recently, we have explored parallelization for ROMS using the MPI programming model. In this paper, an efficient parallelization strategy for such a large-scale scientific software package, based on an existing shared-memory computing model, is presented. In addition, scientific applications and data-performance issues on a couple of SGI systems, including Columbia, the world's third-fastest supercomputer, are discussed.« less

Optimized Laplacian image sharpening algorithm based on graphic processing unit

NASA Astrophysics Data System (ADS)

Ma, Tinghuai; Li, Lu; Ji, Sai; Wang, Xin; Tian, Yuan; Al-Dhelaan, Abdullah; Al-Rodhaan, Mznah

2014-12-01

In classical Laplacian image sharpening, all pixels are processed one by one, which leads to large amount of computation. Traditional Laplacian sharpening processed on CPU is considerably time-consuming especially for those large pictures. In this paper, we propose a parallel implementation of Laplacian sharpening based on Compute Unified Device Architecture (CUDA), which is a computing platform of Graphic Processing Units (GPU), and analyze the impact of picture size on performance and the relationship between the processing time of between data transfer time and parallel computing time. Further, according to different features of different memory, an improved scheme of our method is developed, which exploits shared memory in GPU instead of global memory and further increases the efficiency. Experimental results prove that two novel algorithms outperform traditional consequentially method based on OpenCV in the aspect of computing speed.

Transcribing and digitizing eighteenth- and nineteenth-century letters for a historical digital repository.

PubMed

Dunster, Emily S; Kipnis, Daniel G; Angelo, F Michael

2014-01-01

In fall 2011, the Scott Memorial Library purchased 53 letters belonging to an 1841 graduate of Jefferson Medical College, John Plimpton Green. The library staff transcribed and digitized the letters, creating an online collection in the university's institutional repository, Jefferson Digital Commons. This article will detail the process of transcribing and digitizing the collection along with sharing statistics and the benefits of this project to global researchers.

Accelerate quasi Monte Carlo method for solving systems of linear algebraic equations through shared memory

NASA Astrophysics Data System (ADS)

Lai, Siyan; Xu, Ying; Shao, Bo; Guo, Menghan; Lin, Xiaola

2017-04-01

In this paper we study on Monte Carlo method for solving systems of linear algebraic equations (SLAE) based on shared memory. Former research demostrated that GPU can effectively speed up the computations of this issue. Our purpose is to optimize Monte Carlo method simulation on GPUmemoryachritecture specifically. Random numbers are organized to storein shared memory, which aims to accelerate the parallel algorithm. Bank conflicts can be avoided by our Collaborative Thread Arrays(CTA)scheme. The results of experiments show that the shared memory based strategy can speed up the computaions over than 3X at most.

Time Constraints and Resource Sharing in Adults' Working Memory Spans

ERIC Educational Resources Information Center

Barrouillet, Pierre; Bernardin, Sophie; Camos, Valerie

2004-01-01

This article presents a new model that accounts for working memory spans in adults, the time-based resource-sharing model. The model assumes that both components (i.e., processing and maintenance) of the main working memory tasks require attention and that memory traces decay as soon as attention is switched away. Because memory retrievals are…

Externalising the autobiographical self: sharing personal memories online facilitated memory retention.

PubMed

Wang, Qi; Lee, Dasom; Hou, Yubo

2017-07-01

Internet technology provides a new means of recalling and sharing personal memories in the digital age. What is the mnemonic consequence of posting personal memories online? Theories of transactive memory and autobiographical memory would make contrasting predictions. In the present study, college students completed a daily diary for a week, listing at the end of each day all the events that happened to them on that day. They also reported whether they posted any of the events online. Participants received a surprise memory test after the completion of the diary recording and then another test a week later. At both tests, events posted online were significantly more likely than those not posted online to be recalled. It appears that sharing memories online may provide unique opportunities for rehearsal and meaning-making that facilitate memory retention.

Shared versus distributed memory multiprocessors

NASA Technical Reports Server (NTRS)

Jordan, Harry F.

1991-01-01

The question of whether multiprocessors should have shared or distributed memory has attracted a great deal of attention. Some researchers argue strongly for building distributed memory machines, while others argue just as strongly for programming shared memory multiprocessors. A great deal of research is underway on both types of parallel systems. Special emphasis is placed on systems with a very large number of processors for computation intensive tasks and considers research and implementation trends. It appears that the two types of systems will likely converge to a common form for large scale multiprocessors.

Visual and Spatial Working Memory Are Not that Dissociated after All: A Time-Based Resource-Sharing Account

ERIC Educational Resources Information Center

Vergauwe, Evie; Barrouillet, Pierre; Camos, Valerie

2009-01-01

Examinations of interference between visual and spatial materials in working memory have suggested domain- and process-based fractionations of visuo-spatial working memory. The present study examined the role of central time-based resource sharing in visuo-spatial working memory and assessed its role in obtained interference patterns. Visual and…

Rapid recovery from transient faults in the fault-tolerant processor with fault-tolerant shared memory

NASA Technical Reports Server (NTRS)

Harper, Richard E.; Butler, Bryan P.

1990-01-01

The Draper fault-tolerant processor with fault-tolerant shared memory (FTP/FTSM), which is designed to allow application tasks to continue execution during the memory alignment process, is described. Processor performance is not affected by memory alignment. In addition, the FTP/FTSM incorporates a hardware scrubber device to perform the memory alignment quickly during unused memory access cycles. The FTP/FTSM architecture is described, followed by an estimate of the time required for channel reintegration.

Relations of maternal style and child self-concept to autobiographical memories in chinese, chinese immigrant, and European american 3-year-olds.

PubMed

Wang, Qi

2006-01-01

The relations of maternal reminiscing style and child self-concept to children's shared and independent autobiographical memories were examined in a sample of 189 three-year-olds and their mothers from Chinese families in China, first-generation Chinese immigrant families in the United States, and European American families. Mothers shared memories with their children and completed questionnaires; children recounted autobiographical events and described themselves with a researcher. Independent of culture, gender, child age, and language skills, maternal elaborations and evaluations were associated with children's shared memory reports, and maternal evaluations and child agentic self-focus were associated with children's independent memory reports. Maternal style and child self-concept further mediated cultural influences on children's memory. The findings provide insight into the social-cultural construction of autobiographical memory.

SAHAYOG: A Testbed for Load Sharing under Failure,

DTIC Science & Technology

1987-07-01

messages, shared memory and semaphores . To communicate using messages, processes create message queues using system-provided prim- itives. The message...The size of the memory that is to be shared is decided by the process when it makes a request for memory allocation. The semaphore option of IPC can be...used to prevent two or more concurrent processes from executing their critical sections at the same time. Semaphores must be used when the processes

Implementation and evaluation of shared-memory communication and synchronization operations in MPICH2 using the Nemesis communication subsystem.

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

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

2007-09-01

This paper presents the implementation of MPICH2 over the Nemesis communication subsystem and the evaluation of its shared-memory performance. We describe design issues as well as some of the optimization techniques we employed. We conducted a performance evaluation over shared memory using microbenchmarks. The evaluation shows that MPICH2 Nemesis has very low communication overhead, making it suitable for smaller-grained applications.

Comparison of two paradigms for distributed shared memory

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

Levelt, W.G.; Kaashoek, M.F.; Bal, H.E.

1990-08-01

The paper compares two paradigms for Distributed Shared Memory on loosely coupled computing systems: the shared data-object model as used in Orca, a programming language specially designed for loosely coupled computing systems and the Shared Virtual Memory model. For both paradigms the authors have implemented two systems, one using only point-to-point messages, the other using broadcasting as well. They briefly describe these two paradigms and their implementations. Then they compare their performance on four applications: the traveling salesman problem, alpha-beta search, matrix multiplication and the all pairs shortest paths problem. The measurements show that both paradigms can be used efficientlymore » for programming large-grain parallel applications. Significant speedups were obtained on all applications. The unstructured Shared Virtual Memory paradigm achieves the best absolute performance, although this is largely due to the preliminary nature of the Orca compiler used. The structured shared data-object model achieves the highest speedups and is much easier to program and to debug.« less

Accessing global data from accelerator devices

DOEpatents

Bertolli, Carlo; O'Brien, John K.; Sallenave, Olivier H.; Sura, Zehra N.

2016-12-06

An aspect includes a table of contents (TOC) that was generated by a compiler being received at an accelerator device. The TOC includes an address of global data in a host memory space. The global data is copied from the address in the host memory space to an address in the device memory space. The address in the host memory space is obtained from the received TOC. The received TOC is updated to indicate that global data is stored at the address in the device memory space. A kernel that accesses the global data from the address in the device memory space is executed. The address in the device memory space is obtained based on contents of the updated TOC. When the executing is completed, the global data from the address in the device memory space is copied to the address in the host memory space.

Accessing global data from accelerator devices

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

Bertolli, Carlo; O'Brien, John K.; Sallenave, Olivier H.

2016-12-06

An aspect includes a table of contents (TOC) that was generated by a compiler being received at an accelerator device. The TOC includes an address of global data in a host memory space. The global data is copied from the address in the host memory space to an address in the device memory space. The address in the host memory space is obtained from the received TOC. The received TOC is updated to indicate that global data is stored at the address in the device memory space. A kernel that accesses the global data from the address in the devicemore » memory space is executed. The address in the device memory space is obtained based on contents of the updated TOC. When the executing is completed, the global data from the address in the device memory space is copied to the address in the host memory space.« less

Working memory resources are shared across sensory modalities.

PubMed

Salmela, V R; Moisala, M; Alho, K

2014-10-01

A common assumption in the working memory literature is that the visual and auditory modalities have separate and independent memory stores. Recent evidence on visual working memory has suggested that resources are shared between representations, and that the precision of representations sets the limit for memory performance. We tested whether memory resources are also shared across sensory modalities. Memory precision for two visual (spatial frequency and orientation) and two auditory (pitch and tone duration) features was measured separately for each feature and for all possible feature combinations. Thus, only the memory load was varied, from one to four features, while keeping the stimuli similar. In Experiment 1, two gratings and two tones-both containing two varying features-were presented simultaneously. In Experiment 2, two gratings and two tones-each containing only one varying feature-were presented sequentially. The memory precision (delayed discrimination threshold) for a single feature was close to the perceptual threshold. However, as the number of features to be remembered was increased, the discrimination thresholds increased more than twofold. Importantly, the decrease in memory precision did not depend on the modality of the other feature(s), or on whether the features were in the same or in separate objects. Hence, simultaneously storing one visual and one auditory feature had an effect on memory precision equal to those of simultaneously storing two visual or two auditory features. The results show that working memory is limited by the precision of the stored representations, and that working memory can be described as a resource pool that is shared across modalities.

Representational explanations of “process” dissociations in recognition: The DRYAD theory of aging and memory judgments

PubMed Central

Benjamin, Aaron S.

2011-01-01

It is widely assumed that older adults suffer a deficit in the psychological processes that underlie remembering of contextual or source information. This conclusion is based in large part on empirical interactions, including disordinal ones, that reveal differential effects of manipulations of memory strength on recognition in young and old subjects. This paper lays out an alternative theory that takes as a starting point the overwhelming evidence from the psychometric literature that the effects of age on memory share a single mediating influence. Thus, the theory assumes no differences between younger and older subjects other than a global difference in memory fidelity—that is, the older subjects are presumed to have less valid representations of events and objects than are young subjects. The theory is articulated through three major assumptions and implemented in a computational model, DRYAD, in order to simulate fundamental results in the literature on aging and recognition, including the very interactions taken to imply selective impairment in older people. The theoretical perspective presented here allows for a critical examination of the widely held belief that aging entails the selective disruption of particular memory processes. PMID:20822289

Performance Modeling and Measurement of Parallelized Code for Distributed Shared Memory Multiprocessors

NASA Technical Reports Server (NTRS)

Waheed, Abdul; Yan, Jerry

1998-01-01

This paper presents a model to evaluate the performance and overhead of parallelizing sequential code using compiler directives for multiprocessing on distributed shared memory (DSM) systems. With increasing popularity of shared address space architectures, it is essential to understand their performance impact on programs that benefit from shared memory multiprocessing. We present a simple model to characterize the performance of programs that are parallelized using compiler directives for shared memory multiprocessing. We parallelized the sequential implementation of NAS benchmarks using native Fortran77 compiler directives for an Origin2000, which is a DSM system based on a cache-coherent Non Uniform Memory Access (ccNUMA) architecture. We report measurement based performance of these parallelized benchmarks from four perspectives: efficacy of parallelization process; scalability; parallelization overhead; and comparison with hand-parallelized and -optimized version of the same benchmarks. Our results indicate that sequential programs can conveniently be parallelized for DSM systems using compiler directives but realizing performance gains as predicted by the performance model depends primarily on minimizing architecture-specific data locality overhead.

Distributed simulation using a real-time shared memory network

NASA Technical Reports Server (NTRS)

Simon, Donald L.; Mattern, Duane L.; Wong, Edmond; Musgrave, Jeffrey L.

1993-01-01

The Advanced Control Technology Branch of the NASA Lewis Research Center performs research in the area of advanced digital controls for aeronautic and space propulsion systems. This work requires the real-time implementation of both control software and complex dynamical models of the propulsion system. We are implementing these systems in a distributed, multi-vendor computer environment. Therefore, a need exists for real-time communication and synchronization between the distributed multi-vendor computers. A shared memory network is a potential solution which offers several advantages over other real-time communication approaches. A candidate shared memory network was tested for basic performance. The shared memory network was then used to implement a distributed simulation of a ramjet engine. The accuracy and execution time of the distributed simulation was measured and compared to the performance of the non-partitioned simulation. The ease of partitioning the simulation, the minimal time required to develop for communication between the processors and the resulting execution time all indicate that the shared memory network is a real-time communication technique worthy of serious consideration.

Multiprocessor shared-memory information exchange

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

Santoline, L.L.; Bowers, M.D.; Crew, A.W.

1989-02-01

In distributed microprocessor-based instrumentation and control systems, the inter-and intra-subsystem communication requirements ultimately form the basis for the overall system architecture. This paper describes a software protocol which addresses the intra-subsystem communications problem. Specifically the protocol allows for multiple processors to exchange information via a shared-memory interface. The authors primary goal is to provide a reliable means for information to be exchanged between central application processor boards (masters) and dedicated function processor boards (slaves) in a single computer chassis. The resultant Multiprocessor Shared-Memory Information Exchange (MSMIE) protocol, a standard master-slave shared-memory interface suitable for use in nuclear safety systems, ismore » designed to pass unidirectional buffers of information between the processors while providing a minimum, deterministic cycle time for this data exchange.« less

Memory access in shared virtual memory

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

Berrendorf, R.

1992-01-01

Shared virtual memory (SVM) is a virtual memory layer with a single address space on top of a distributed real memory on parallel computers. We examine the behavior and performance of SVM running a parallel program with medium-grained, loop-level parallelism on top of it. A simulator for the underlying parallel architecture can be used to examine the behavior of SVM more deeply. The influence of several parameters, such as the number of processors, page size, cold or warm start, and restricted page replication, is studied.

Memory access in shared virtual memory

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

Berrendorf, R.

1992-09-01

Shared virtual memory (SVM) is a virtual memory layer with a single address space on top of a distributed real memory on parallel computers. We examine the behavior and performance of SVM running a parallel program with medium-grained, loop-level parallelism on top of it. A simulator for the underlying parallel architecture can be used to examine the behavior of SVM more deeply. The influence of several parameters, such as the number of processors, page size, cold or warm start, and restricted page replication, is studied.

Parallel processing approach to transform-based image coding

NASA Astrophysics Data System (ADS)

Normile, James O.; Wright, Dan; Chu, Ken; Yeh, Chia L.

1991-06-01

This paper describes a flexible parallel processing architecture designed for use in real time video processing. The system consists of floating point DSP processors connected to each other via fast serial links, each processor has access to a globally shared memory. A multiple bus architecture in combination with a dual ported memory allows communication with a host control processor. The system has been applied to prototyping of video compression and decompression algorithms. The decomposition of transform based algorithms for decompression into a form suitable for parallel processing is described. A technique for automatic load balancing among the processors is developed and discussed, results ar presented with image statistics and data rates. Finally techniques for accelerating the system throughput are analyzed and results from the application of one such modification described.

Spaceborne Processor Array

NASA Technical Reports Server (NTRS)

Chow, Edward T.; Schatzel, Donald V.; Whitaker, William D.; Sterling, Thomas

2008-01-01

A Spaceborne Processor Array in Multifunctional Structure (SPAMS) can lower the total mass of the electronic and structural overhead of spacecraft, resulting in reduced launch costs, while increasing the science return through dynamic onboard computing. SPAMS integrates the multifunctional structure (MFS) and the Gilgamesh Memory, Intelligence, and Network Device (MIND) multi-core in-memory computer architecture into a single-system super-architecture. This transforms every inch of a spacecraft into a sharable, interconnected, smart computing element to increase computing performance while simultaneously reducing mass. The MIND in-memory architecture provides a foundation for high-performance, low-power, and fault-tolerant computing. The MIND chip has an internal structure that includes memory, processing, and communication functionality. The Gilgamesh is a scalable system comprising multiple MIND chips interconnected to operate as a single, tightly coupled, parallel computer. The array of MIND components shares a global, virtual name space for program variables and tasks that are allocated at run time to the distributed physical memory and processing resources. Individual processor- memory nodes can be activated or powered down at run time to provide active power management and to configure around faults. A SPAMS system is comprised of a distributed Gilgamesh array built into MFS, interfaces into instrument and communication subsystems, a mass storage interface, and a radiation-hardened flight computer.

Apathy, but not depression, is associated with executive dysfunction in cerebral small vessel disease

PubMed Central

Hollocks, Matthew J.; Morris, Robin G.; Markus, Hugh S.

2017-01-01

Objective To determine the prevalence of apathy and depression in cerebral small vessel disease (SVD), and the relationships between both apathy and depression with cognition. To examine whether apathy is specifically related to impairment in executive functioning and processing speed. Methods 196 patients with a clinical lacunar stroke and an anatomically corresponding lacunar infarct on MRI were compared to 300 stroke-free controls. Apathy and depression were measured using the Geriatric Depression Scale, and cognitive functioning was assessed using an SVD cognitive screening tool, the Brief Memory and Executive Test, which measures executive functioning/processing speed and memory/orientation. Path analysis and binary logistic regression were used to assess the relation between apathy, depression and cognitive impairment. Results 31 participants with SVD (15.8%) met criteria for apathy only, 23 (11.8%) for both apathy and depression, and 2 (1.0%) for depression only. In the SVD group the presence of apathy was related to global cognition, and specifically to impaired executive functioning/processing speed, but not memory/orientation. The presence of depression was not related to global cognition, impaired executive functioning/processing speed or memory/orientation. Conclusions Apathy is a common feature of SVD and is associated with impaired executive functioning/processing speed suggesting the two may share biological mechanisms. Screening for apathy should be considered in SVD, and further work is required to develop and evaluate effective apathy treatment or management in SVD. PMID:28493898

Working Memory Span Development: A Time-Based Resource-Sharing Model Account

ERIC Educational Resources Information Center

Barrouillet, Pierre; Gavens, Nathalie; Vergauwe, Evie; Gaillard, Vinciane; Camos, Valerie

2009-01-01

The time-based resource-sharing model (P. Barrouillet, S. Bernardin, & V. Camos, 2004) assumes that during complex working memory span tasks, attention is frequently and surreptitiously switched from processing to reactivate decaying memory traces before their complete loss. Three experiments involving children from 5 to 14 years of age…

Direct access inter-process shared memory

DOEpatents

Brightwell, Ronald B; Pedretti, Kevin; Hudson, Trammell B

2013-10-22

A technique for directly sharing physical memory between processes executing on processor cores is described. The technique includes loading a plurality of processes into the physical memory for execution on a corresponding plurality of processor cores sharing the physical memory. An address space is mapped to each of the processes by populating a first entry in a top level virtual address table for each of the processes. The address space of each of the processes is cross-mapped into each of the processes by populating one or more subsequent entries of the top level virtual address table with the first entry in the top level virtual address table from other processes.

Memory Network For Distributed Data Processors

NASA Technical Reports Server (NTRS)

Bolen, David; Jensen, Dean; Millard, ED; Robinson, Dave; Scanlon, George

1992-01-01

Universal Memory Network (UMN) is modular, digital data-communication system enabling computers with differing bus architectures to share 32-bit-wide data between locations up to 3 km apart with less than one millisecond of latency. Makes it possible to design sophisticated real-time and near-real-time data-processing systems without data-transfer "bottlenecks". This enterprise network permits transmission of volume of data equivalent to an encyclopedia each second. Facilities benefiting from Universal Memory Network include telemetry stations, simulation facilities, power-plants, and large laboratories or any facility sharing very large volumes of data. Main hub of UMN is reflection center including smaller hubs called Shared Memory Interfaces.

Grouping and binding in visual short-term memory.

PubMed

Quinlan, Philip T; Cohen, Dale J

2012-09-01

Findings of 2 experiments are reported that challenge the current understanding of visual short-term memory (VSTM). In both experiments, a single study display, containing 6 colored shapes, was presented briefly and then probed with a single colored shape. At stake is how VSTM retains a record of different objects that share common features: In the 1st experiment, 2 study items sometimes shared a common feature (either a shape or a color). The data revealed a color sharing effect, in which memory was much better for items that shared a common color than for items that did not. The 2nd experiment showed that the size of the color sharing effect depended on whether a single pair of items shared a common color or whether 2 pairs of items were so defined-memory for all items improved when 2 color groups were presented. In explaining performance, an account is advanced in which items compete for a fixed number of slots, but then memory recall for any given stored item is prone to error. A critical assumption is that items that share a common color are stored together in a slot as a chunk. The evidence provides further support for the idea that principles of perceptual organization may determine the manner in which items are stored in VSTM. PsycINFO Database Record (c) 2012 APA, all rights reserved.

The force on the flex: Global parallelism and portability

NASA Technical Reports Server (NTRS)

Jordan, H. F.

1986-01-01

A parallel programming methodology, called the force, supports the construction of programs to be executed in parallel by an unspecified, but potentially large, number of processes. The methodology was originally developed on a pipelined, shared memory multiprocessor, the Denelcor HEP, and embodies the primitive operations of the force in a set of macros which expand into multiprocessor Fortran code. A small set of primitives is sufficient to write large parallel programs, and the system has been used to produce 10,000 line programs in computational fluid dynamics. The level of complexity of the force primitives is intermediate. It is high enough to mask detailed architectural differences between multiprocessors but low enough to give the user control over performance. The system is being ported to a medium scale multiprocessor, the Flex/32, which is a 20 processor system with a mixture of shared and local memory. Memory organization and the type of processor synchronization supported by the hardware on the two machines lead to some differences in efficient implementations of the force primitives, but the user interface remains the same. An initial implementation was done by retargeting the macros to Flexible Computer Corporation's ConCurrent C language. Subsequently, the macros were caused to directly produce the system calls which form the basis for ConCurrent C. The implementation of the Fortran based system is in step with Flexible Computer Corporations's implementation of a Fortran system in the parallel environment.

Changes in Brain Network Efficiency and Working Memory Performance in Aging

PubMed Central

Stanley, Matthew L.; Simpson, Sean L.; Dagenbach, Dale; Lyday, Robert G.; Burdette, Jonathan H.; Laurienti, Paul J.

2015-01-01

Working memory is a complex psychological construct referring to the temporary storage and active processing of information. We used functional connectivity brain network metrics quantifying local and global efficiency of information transfer for predicting individual variability in working memory performance on an n-back task in both young (n = 14) and older (n = 15) adults. Individual differences in both local and global efficiency during the working memory task were significant predictors of working memory performance in addition to age (and an interaction between age and global efficiency). Decreases in local efficiency during the working memory task were associated with better working memory performance in both age cohorts. In contrast, increases in global efficiency were associated with much better working performance for young participants; however, increases in global efficiency were associated with a slight decrease in working memory performance for older participants. Individual differences in local and global efficiency during resting-state sessions were not significant predictors of working memory performance. Significant group whole-brain functional network decreases in local efficiency also were observed during the working memory task compared to rest, whereas no significant differences were observed in network global efficiency. These results are discussed in relation to recently developed models of age-related differences in working memory. PMID:25875001

Changes in brain network efficiency and working memory performance in aging.

PubMed

Stanley, Matthew L; Simpson, Sean L; Dagenbach, Dale; Lyday, Robert G; Burdette, Jonathan H; Laurienti, Paul J

2015-01-01

Working memory is a complex psychological construct referring to the temporary storage and active processing of information. We used functional connectivity brain network metrics quantifying local and global efficiency of information transfer for predicting individual variability in working memory performance on an n-back task in both young (n = 14) and older (n = 15) adults. Individual differences in both local and global efficiency during the working memory task were significant predictors of working memory performance in addition to age (and an interaction between age and global efficiency). Decreases in local efficiency during the working memory task were associated with better working memory performance in both age cohorts. In contrast, increases in global efficiency were associated with much better working performance for young participants; however, increases in global efficiency were associated with a slight decrease in working memory performance for older participants. Individual differences in local and global efficiency during resting-state sessions were not significant predictors of working memory performance. Significant group whole-brain functional network decreases in local efficiency also were observed during the working memory task compared to rest, whereas no significant differences were observed in network global efficiency. These results are discussed in relation to recently developed models of age-related differences in working memory.

Shared memories reveal shared structure in neural activity across individuals

PubMed Central

Chen, J.; Leong, Y.C.; Honey, C.J.; Yong, C.H.; Norman, K.A.; Hasson, U.

2016-01-01

Our lives revolve around sharing experiences and memories with others. When different people recount the same events, how similar are their underlying neural representations? Participants viewed a fifty-minute movie, then verbally described the events during functional MRI, producing unguided detailed descriptions lasting up to forty minutes. As each person spoke, event-specific spatial patterns were reinstated in default-network, medial-temporal, and high-level visual areas. Individual event patterns were both highly discriminable from one another and similar between people, suggesting consistent spatial organization. In many high-order areas, patterns were more similar between people recalling the same event than between recall and perception, indicating systematic reshaping of percept into memory. These results reveal the existence of a common spatial organization for memories in high-level cortical areas, where encoded information is largely abstracted beyond sensory constraints; and that neural patterns during perception are altered systematically across people into shared memory representations for real-life events. PMID:27918531

Parallel computing for probabilistic fatigue analysis

NASA Technical Reports Server (NTRS)

Sues, Robert H.; Lua, Yuan J.; Smith, Mark D.

1993-01-01

This paper presents the results of Phase I research to investigate the most effective parallel processing software strategies and hardware configurations for probabilistic structural analysis. We investigate the efficiency of both shared and distributed-memory architectures via a probabilistic fatigue life analysis problem. We also present a parallel programming approach, the virtual shared-memory paradigm, that is applicable across both types of hardware. Using this approach, problems can be solved on a variety of parallel configurations, including networks of single or multiprocessor workstations. We conclude that it is possible to effectively parallelize probabilistic fatigue analysis codes; however, special strategies will be needed to achieve large-scale parallelism to keep large number of processors busy and to treat problems with the large memory requirements encountered in practice. We also conclude that distributed-memory architecture is preferable to shared-memory for achieving large scale parallelism; however, in the future, the currently emerging hybrid-memory architectures will likely be optimal.

Mnemonic transmission, social contagion, and emergence of collective memory: Influence of emotional valence, group structure, and information distribution.

PubMed

Choi, Hae-Yoon; Kensinger, Elizabeth A; Rajaram, Suparna

2017-09-01

Social transmission of memory and its consequence on collective memory have generated enduring interdisciplinary interest because of their widespread significance in interpersonal, sociocultural, and political arenas. We tested the influence of 3 key factors-emotional salience of information, group structure, and information distribution-on mnemonic transmission, social contagion, and collective memory. Participants individually studied emotionally salient (negative or positive) and nonemotional (neutral) picture-word pairs that were completely shared, partially shared, or unshared within participant triads, and then completed 3 consecutive recalls in 1 of 3 conditions: individual-individual-individual (control), collaborative-collaborative (identical group; insular structure)-individual, and collaborative-collaborative (reconfigured group; diverse structure)-individual. Collaboration enhanced negative memories especially in insular group structure and especially for shared information, and promoted collective forgetting of positive memories. Diverse group structure reduced this negativity effect. Unequally distributed information led to social contagion that creates false memories; diverse structure propagated a greater variety of false memories whereas insular structure promoted confidence in false recognition and false collective memory. A simultaneous assessment of network structure, information distribution, and emotional valence breaks new ground to specify how network structure shapes the spread of negative memories and false memories, and the emergence of collective memory. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Effects of cacheing on multitasking efficiency and programming strategy on an ELXSI 6400

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

Montry, G.R.; Benner, R.E.

1985-12-01

The impact of a cache/shared memory architecture, and, in particular, the cache coherency problem, upon concurrent algorithm and program development is discussed. In this context, a simple set of programming strategies are proposed which streamline code development and improve code performance when multitasking in a cache/shared memory or distributed memory environment.

Implementation of a parallel unstructured Euler solver on shared and distributed memory architectures

NASA Technical Reports Server (NTRS)

Mavriplis, D. J.; Das, Raja; Saltz, Joel; Vermeland, R. E.

1992-01-01

An efficient three dimensional unstructured Euler solver is parallelized on a Cray Y-MP C90 shared memory computer and on an Intel Touchstone Delta distributed memory computer. This paper relates the experiences gained and describes the software tools and hardware used in this study. Performance comparisons between two differing architectures are made.

Multitasking OS manages a team of processors

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

Ripps, D.L.

1983-07-21

MTOS-68k is a real-time multitasking operating system designed for the popular MC68000 microprocessors. It aproaches task coordination and synchronization in a fashion that matches uniquely the structural simplicity and regularity of the 68000 instruction set. Since in many 68000 applications the speed and power of one CPU are not enough, MTOS-68k has been designed to support multiple processors, as well as multiple tasks. Typically, the devices are tightly coupled single-board computers, that is they share a backplane and parts of global memory.

Sleep Benefits Memory for Semantic Category Structure While Preserving Exemplar-Specific Information.

PubMed

Schapiro, Anna C; McDevitt, Elizabeth A; Chen, Lang; Norman, Kenneth A; Mednick, Sara C; Rogers, Timothy T

2017-11-01

Semantic memory encompasses knowledge about both the properties that typify concepts (e.g. robins, like all birds, have wings) as well as the properties that individuate conceptually related items (e.g. robins, in particular, have red breasts). We investigate the impact of sleep on new semantic learning using a property inference task in which both kinds of information are initially acquired equally well. Participants learned about three categories of novel objects possessing some properties that were shared among category exemplars and others that were unique to an exemplar, with exposure frequency varying across categories. In Experiment 1, memory for shared properties improved and memory for unique properties was preserved across a night of sleep, while memory for both feature types declined over a day awake. In Experiment 2, memory for shared properties improved across a nap, but only for the lower-frequency category, suggesting a prioritization of weakly learned information early in a sleep period. The increase was significantly correlated with amount of REM, but was also observed in participants who did not enter REM, suggesting involvement of both REM and NREM sleep. The results provide the first evidence that sleep improves memory for the shared structure of object categories, while simultaneously preserving object-unique information.

Automatic Generation of Directive-Based Parallel Programs for Shared Memory Parallel Systems

NASA Technical Reports Server (NTRS)

Jin, Hao-Qiang; Yan, Jerry; Frumkin, Michael

2000-01-01

The shared-memory programming model is a very effective way to achieve parallelism on shared memory parallel computers. As great progress was made in hardware and software technologies, performance of parallel programs with compiler directives has demonstrated large improvement. The introduction of OpenMP directives, the industrial standard for shared-memory programming, has minimized the issue of portability. Due to its ease of programming and its good performance, the technique has become very popular. In this study, we have extended CAPTools, a computer-aided parallelization toolkit, to automatically generate directive-based, OpenMP, parallel programs. We outline techniques used in the implementation of the tool and present test results on the NAS parallel benchmarks and ARC3D, a CFD application. This work demonstrates the great potential of using computer-aided tools to quickly port parallel programs and also achieve good performance.

Structurally Integrated Versus Structurally Segregated Memory Representations: Implications for the Design of Instructional Materials.

ERIC Educational Resources Information Center

Hayes-Roth, Barbara

Two kinds of memory organization are distinguished: segregrated versus integrated. In segregated memory organizations, related learned propositions have separate memory representations. In integrated memory organizations, memory representations of related propositions share common subrepresentations. Segregated memory organizations facilitate…

Getting connected: Both associative and semantic links structure semantic memory for newly learned persons.

PubMed

Wiese, Holger; Schweinberger, Stefan R

2015-01-01

The present study examined whether semantic memory for newly learned people is structured by visual co-occurrence, shared semantics, or both. Participants were trained with pairs of simultaneously presented (i.e., co-occurring) preexperimentally unfamiliar faces, which either did or did not share additionally provided semantic information (occupation, place of living, etc.). Semantic information could also be shared between faces that did not co-occur. A subsequent priming experiment revealed faster responses for both co-occurrence/no shared semantics and no co-occurrence/shared semantics conditions, than for an unrelated condition. Strikingly, priming was strongest in the co-occurrence/shared semantics condition, suggesting additive effects of these factors. Additional analysis of event-related brain potentials yielded priming in the N400 component only for combined effects of visual co-occurrence and shared semantics, with more positive amplitudes in this than in the unrelated condition. Overall, these findings suggest that both semantic relatedness and visual co-occurrence are important when novel information is integrated into person-related semantic memory.

Memory T and memory B cells share a transcriptional program of self-renewal with long-term hematopoietic stem cells

PubMed Central

Luckey, Chance John; Bhattacharya, Deepta; Goldrath, Ananda W.; Weissman, Irving L.; Benoist, Christophe; Mathis, Diane

2006-01-01

The only cells of the hematopoietic system that undergo self-renewal for the lifetime of the organism are long-term hematopoietic stem cells and memory T and B cells. To determine whether there is a shared transcriptional program among these self-renewing populations, we first compared the gene-expression profiles of naïve, effector and memory CD8+ T cells with those of long-term hematopoietic stem cells, short-term hematopoietic stem cells, and lineage-committed progenitors. Transcripts augmented in memory CD8+ T cells relative to naïve and effector T cells were selectively enriched in long-term hematopoietic stem cells and were progressively lost in their short-term and lineage-committed counterparts. Furthermore, transcripts selectively decreased in memory CD8+ T cells were selectively down-regulated in long-term hematopoietic stem cells and progressively increased with differentiation. To confirm that this pattern was a general property of immunologic memory, we turned to independently generated gene expression profiles of memory, naïve, germinal center, and plasma B cells. Once again, memory-enriched and -depleted transcripts were also appropriately augmented and diminished in long-term hematopoietic stem cells, and their expression correlated with progressive loss of self-renewal function. Thus, there appears to be a common signature of both up- and down-regulated transcripts shared between memory T cells, memory B cells, and long-term hematopoietic stem cells. This signature was not consistently enriched in neural or embryonic stem cell populations and, therefore, appears to be restricted to the hematopoeitic system. These observations provide evidence that the shared phenotype of self-renewal in the hematopoietic system is linked at the molecular level. PMID:16492737

System and method for programmable bank selection for banked memory subsystems

DOEpatents

Blumrich, Matthias A.; Chen, Dong; Gara, Alan G.; Giampapa, Mark E.; Hoenicke, Dirk; Ohmacht, Martin; Salapura, Valentina; Sugavanam, Krishnan

2010-09-07

A programmable memory system and method for enabling one or more processor devices access to shared memory in a computing environment, the shared memory including one or more memory storage structures having addressable locations for storing data. The system comprises: one or more first logic devices associated with a respective one or more processor devices, each first logic device for receiving physical memory address signals and programmable for generating a respective memory storage structure select signal upon receipt of pre-determined address bit values at selected physical memory address bit locations; and, a second logic device responsive to each of the respective select signal for generating an address signal used for selecting a memory storage structure for processor access. The system thus enables each processor device of a computing environment memory storage access distributed across the one or more memory storage structures.

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.

Automatic Parallelization of Numerical Python Applications using the Global Arrays Toolkit

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

Daily, Jeffrey A.; Lewis, Robert R.

2011-11-30

Global Arrays is a software system from Pacific Northwest National Laboratory that enables an efficient, portable, and parallel shared-memory programming interface to manipulate distributed dense arrays. The NumPy module is the de facto standard for numerical calculation in the Python programming language, a language whose use is growing rapidly in the scientific and engineering communities. NumPy provides a powerful N-dimensional array class as well as other scientific computing capabilities. However, like the majority of the core Python modules, NumPy is inherently serial. Using a combination of Global Arrays and NumPy, we have reimplemented NumPy as a distributed drop-in replacement calledmore » Global Arrays in NumPy (GAiN). Serial NumPy applications can become parallel, scalable GAiN applications with only minor source code changes. Scalability studies of several different GAiN applications will be presented showing the utility of developing serial NumPy codes which can later run on more capable clusters or supercomputers.« less

Shared Memory Parallelization of an Implicit ADI-type CFD Code

NASA Technical Reports Server (NTRS)

Hauser, Th.; Huang, P. G.

1999-01-01

A parallelization study designed for ADI-type algorithms is presented using the OpenMP specification for shared-memory multiprocessor programming. Details of optimizations specifically addressed to cache-based computer architectures are described and performance measurements for the single and multiprocessor implementation are summarized. The paper demonstrates that optimization of memory access on a cache-based computer architecture controls the performance of the computational algorithm. A hybrid MPI/OpenMP approach is proposed for clusters of shared memory machines to further enhance the parallel performance. The method is applied to develop a new LES/DNS code, named LESTool. A preliminary DNS calculation of a fully developed channel flow at a Reynolds number of 180, Re(sub tau) = 180, has shown good agreement with existing data.

Address tracing for parallel machines

NASA Technical Reports Server (NTRS)

Stunkel, Craig B.; Janssens, Bob; Fuchs, W. Kent

1991-01-01

Recently implemented parallel system address-tracing methods based on several metrics are surveyed. The issues specific to collection of traces for both shared and distributed memory parallel computers are highlighted. Five general categories of address-trace collection methods are examined: hardware-captured, interrupt-based, simulation-based, altered microcode-based, and instrumented program-based traces. The problems unique to shared memory and distributed memory multiprocessors are examined separately.

Shared processing in multiple object tracking and visual working memory in the absence of response order and task order confounds

PubMed Central

Howe, Piers D. L.

2017-01-01

To understand how the visual system represents multiple moving objects and how those representations contribute to tracking, it is essential that we understand how the processes of attention and working memory interact. In the work described here we present an investigation of that interaction via a series of tracking and working memory dual-task experiments. Previously, it has been argued that tracking is resistant to disruption by a concurrent working memory task and that any apparent disruption is in fact due to observers making a response to the working memory task, rather than due to competition for shared resources. Contrary to this, in our experiments we find that when task order and response order confounds are avoided, all participants show a similar decrease in both tracking and working memory performance. However, if task and response order confounds are not adequately controlled for we find substantial individual differences, which could explain the previous conflicting reports on this topic. Our results provide clear evidence that tracking and working memory tasks share processing resources. PMID:28410383

Shared processing in multiple object tracking and visual working memory in the absence of response order and task order confounds.

PubMed

Lapierre, Mark D; Cropper, Simon J; Howe, Piers D L

2017-01-01

To understand how the visual system represents multiple moving objects and how those representations contribute to tracking, it is essential that we understand how the processes of attention and working memory interact. In the work described here we present an investigation of that interaction via a series of tracking and working memory dual-task experiments. Previously, it has been argued that tracking is resistant to disruption by a concurrent working memory task and that any apparent disruption is in fact due to observers making a response to the working memory task, rather than due to competition for shared resources. Contrary to this, in our experiments we find that when task order and response order confounds are avoided, all participants show a similar decrease in both tracking and working memory performance. However, if task and response order confounds are not adequately controlled for we find substantial individual differences, which could explain the previous conflicting reports on this topic. Our results provide clear evidence that tracking and working memory tasks share processing resources.

Visual and spatial working memory are not that dissociated after all: a time-based resource-sharing account.

PubMed

Vergauwe, Evie; Barrouillet, Pierre; Camos, Valérie

2009-07-01

Examinations of interference between visual and spatial materials in working memory have suggested domain- and process-based fractionations of visuo-spatial working memory. The present study examined the role of central time-based resource sharing in visuo-spatial working memory and assessed its role in obtained interference patterns. Visual and spatial storage were combined with both visual and spatial on-line processing components in computer-paced working memory span tasks (Experiment 1) and in a selective interference paradigm (Experiment 2). The cognitive load of the processing components was manipulated to investigate its impact on concurrent maintenance for both within-domain and between-domain combinations of processing and storage components. In contrast to both domain- and process-based fractionations of visuo-spatial working memory, the results revealed that recall performance was determined by the cognitive load induced by the processing of items, rather than by the domain to which those items pertained. These findings are interpreted as evidence for a time-based resource-sharing mechanism in visuo-spatial working memory.

A High Performance VLSI Computer Architecture For Computer Graphics

NASA Astrophysics Data System (ADS)

Chin, Chi-Yuan; Lin, Wen-Tai

1988-10-01

A VLSI computer architecture, consisting of multiple processors, is presented in this paper to satisfy the modern computer graphics demands, e.g. high resolution, realistic animation, real-time display etc.. All processors share a global memory which are partitioned into multiple banks. Through a crossbar network, data from one memory bank can be broadcasted to many processors. Processors are physically interconnected through a hyper-crossbar network (a crossbar-like network). By programming the network, the topology of communication links among processors can be reconfigurated to satisfy specific dataflows of different applications. Each processor consists of a controller, arithmetic operators, local memory, a local crossbar network, and I/O ports to communicate with other processors, memory banks, and a system controller. Operations in each processor are characterized into two modes, i.e. object domain and space domain, to fully utilize the data-independency characteristics of graphics processing. Special graphics features such as 3D-to-2D conversion, shadow generation, texturing, and reflection, can be easily handled. With the current high density interconnection (MI) technology, it is feasible to implement a 64-processor system to achieve 2.5 billion operations per second, a performance needed in most advanced graphics applications.

Why are you telling me that? A conceptual model of the social function of autobiographical memory.

PubMed

Alea, Nicole; Bluck, Susan

2003-03-01

In an effort to stimulate and guide empirical work within a functional framework, this paper provides a conceptual model of the social functions of autobiographical memory (AM) across the lifespan. The model delineates the processes and variables involved when AMs are shared to serve social functions. Components of the model include: lifespan contextual influences, the qualitative characteristics of memory (emotionality and level of detail recalled), the speaker's characteristics (age, gender, and personality), the familiarity and similarity of the listener to the speaker, the level of responsiveness during the memory-sharing process, and the nature of the social relationship in which the memory sharing occurs (valence and length of the relationship). These components are shown to influence the type of social function served and/or, the extent to which social functions are served. Directions for future empirical work to substantiate the model and hypotheses derived from the model are provided.

Destination memory impairment in older people.

PubMed

Gopie, Nigel; Craik, Fergus I M; Hasher, Lynn

2010-12-01

Older adults are assumed to have poor destination memory-knowing to whom they tell particular information-and anecdotes about them repeating stories to the same people are cited as informal evidence for this claim. Experiment 1 assessed young and older adults' destination memory by having participants tell facts (e.g., "A dime has 118 ridges around its edge") to pictures of famous people (e.g., Oprah Winfrey). Surprise recognition memory tests, which also assessed confidence, revealed that older adults, compared to young adults, were disproportionately impaired on destination memory relative to spared memory for the individual components (i.e., facts, faces) of the episode. Older adults also were more confident that they had not told a fact to a particular person when they actually had (i.e., a miss); this presumably causes them to repeat information more often than young adults. When the direction of information transfer was reversed in Experiment 2, such that the famous people shared information with the participants (i.e., a source memory experiment), age-related memory differences disappeared. In contrast to the destination memory experiment, older adults in the source memory experiment were more confident than young adults that someone had shared a fact with them when a different person actually had shared the fact (i.e., a false alarm). Overall, accuracy and confidence jointly influence age-related changes to destination memory, a fundamental component of successful communication. (c) 2010 APA, all rights reserved).

Interference due to shared features between action plans is influenced by working memory span.

PubMed

Fournier, Lisa R; Behmer, Lawrence P; Stubblefield, Alexandra M

2014-12-01

In this study, we examined the interactions between the action plans that we hold in memory and the actions that we carry out, asking whether the interference due to shared features between action plans is due to selection demands imposed on working memory. Individuals with low and high working memory spans learned arbitrary motor actions in response to two different visual events (A and B), presented in a serial order. They planned a response to the first event (A) and while maintaining this action plan in memory they then executed a speeded response to the second event (B). Afterward, they executed the action plan for the first event (A) maintained in memory. Speeded responses to the second event (B) were delayed when it shared an action feature (feature overlap) with the first event (A), relative to when it did not (no feature overlap). The size of the feature-overlap delay was greater for low-span than for high-span participants. This indicates that interference due to overlapping action plans is greater when fewer working memory resources are available, suggesting that this interference is due to selection demands imposed on working memory. Thus, working memory plays an important role in managing current and upcoming action plans, at least for newly learned tasks. Also, managing multiple action plans is compromised in individuals who have low versus high working memory spans.

Destination Memory Impairment in Older People

PubMed Central

Gopie, Nigel; Craik, Fergus I. M.; Hasher, Lynn

2012-01-01

Older adults are assumed to have poor destination memory— knowing to whom they tell particular information—and anecdotes about them repeating stories to the same people are cited as informal evidence for this claim. Experiment 1 assessed young and older adults’ destination memory by having participants tell facts (e.g., “A dime has 118 ridges around its edge”) to pictures of famous people (e.g., Oprah Winfrey). Surprise recognition memory tests, which also assessed confidence, revealed that older adults, compared to young adults, were disproportionately impaired on destination memory relative to spared memory for the individual components (i.e., facts, faces) of the episode. Older adults also were more confident that they had not told a fact to a particular person when they actually had (i.e., a miss); this presumably causes them to repeat information more often than young adults. When the direction of information transfer was reversed in Experiment 2, such that the famous people shared information with the participants (i.e., a source memory experiment), age-related memory differences disappeared. In contrast to the destination memory experiment, older adults in the source memory experiment were more confident than young adults that someone had shared a fact with them when a different person actually had shared the fact (i.e., a false alarm). Overall, accuracy and confidence jointly influence age-related changes to destination memory, a fundamental component of successful communication. PMID:20718537

Evaluating the relation between memory and intelligence in children with learning disabilities.

PubMed

Hoerig, Dianne C; David, Andrew S; D'Amato, Rik Carl

2002-12-01

Although both intelligence tests and memory tests are commonly used in neuropsychological examinations, the relationship between memory and intelligence has not been fully explored, particularly for children having learning disabilities. Memory, or the ability to retain information, was evaluated using the Test of Memory and Learning, a recently released test that gives a comprehensive measure of global memory functioning. This, and the Wechsler Intelligence Scale for Children-Third Edition, used to assess intelligence, were given to 80 students with learning disabilities. The correlation between a global measure of memory and a global measure f intelligence was significant (r = .59), indicating that memory should be viewed as an important component when evaluating children with learning disabilities.

First Applications of the New Parallel Krylov Solver for MODFLOW on a National and Global Scale

NASA Astrophysics Data System (ADS)

Verkaik, J.; Hughes, J. D.; Sutanudjaja, E.; van Walsum, P.

2016-12-01

Integrated high-resolution hydrologic models are increasingly being used for evaluating water management measures at field scale. Their drawbacks are large memory requirements and long run times. Examples of such models are The Netherlands Hydrological Instrument (NHI) model and the PCRaster Global Water Balance (PCR-GLOBWB) model. Typical simulation periods are 30-100 years with daily timesteps. The NHI model predicts water demands in periods of drought, supporting operational and long-term water-supply decisions. The NHI is a state-of-the-art coupling of several models: a 7-layer MODFLOW groundwater model ( 6.5M 250m cells), a MetaSWAP model for the unsaturated zone (Richards emulator of 0.5M cells), and a surface water model (MOZART-DM). The PCR-GLOBWB model provides a grid-based representation of global terrestrial hydrology and this work uses the version that includes a 2-layer MODFLOW groundwater model ( 4.5M 10km cells). The Parallel Krylov Solver (PKS) speeds up computation by both distributed memory parallelization (Message Passing Interface) and shared memory parallelization (Open Multi-Processing). PKS includes conjugate gradient, bi-conjugate gradient stabilized, and generalized minimal residual linear accelerators that use an overlapping additive Schwarz domain decomposition preconditioner. PKS can be used for both structured and unstructured grids and has been fully integrated in MODFLOW-USG using METIS partitioning and in iMODFLOW using RCB partitioning. iMODFLOW is an accelerated version of MODFLOW-2005 that is implicitly and online coupled to MetaSWAP. Results for benchmarks carried out on the Cartesius Dutch supercomputer (https://userinfo.surfsara.nl/systems/cartesius) for the PCRGLOB-WB model and on a 2x16 core Windows machine for the NHI model show speedups up to 10-20 and 5-10, respectively.

Mobile Application Removes Societal Barriers to P4 Medicine.

PubMed

Michel, J-P

2017-01-01

The overlap between one innovative paradigm (P4 medicine: predictive, personalized, participatory and preventive) and another (a new definition of "Healthy ageing") is fertile ground for new technologies; a new mobile application (app) that could broaden our scientific knowledge of the ageing process and help us to better analyse the impact of possible interventions in slowing the ageing decline. A novel mobile application is here presented as a game including questions and tests will allow in 10 minutes the assessment of the following domains: robustness, flexibility (lower muscle strength), balance, mental and memory complaints, semantic memory and visual retention. This game is completed by specific measurements, which could allow establishing precise information on functional and cognitive abilities. A global evaluation precedes advice and different types of exercises. The repetition of the tests and measures will allow a long follow up of the individual performances which could be shared (on specific request) with family members and general practitioners.

Low latency memory access and synchronization

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

Blumrich, Matthias A.; Chen, Dong; Coteus, Paul W.

A low latency memory system access is provided in association with a weakly-ordered multiprocessor system. Each processor in the multiprocessor shares resources, and each shared resource has an associated lock within a locking device that provides support for synchronization between the multiple processors in the multiprocessor and the orderly sharing of the resources. A processor only has permission to access a resource when it owns the lock associated with that resource, and an attempt by a processor to own a lock requires only a single load operation, rather than a traditional atomic load followed by store, such that the processormore » only performs a read operation and the hardware locking device performs a subsequent write operation rather than the processor. A simple prefetching for non-contiguous data structures is also disclosed. A memory line is redefined so that in addition to the normal physical memory data, every line includes a pointer that is large enough to point to any other line in the memory, wherein the pointers to determine which memory line to prefetch rather than some other predictive algorithm. This enables hardware to effectively prefetch memory access patterns that are non-contiguous, but repetitive.« less

Low latency memory access and synchronization

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

Blumrich, Matthias A.; Chen, Dong; Coteus, Paul W.

A low latency memory system access is provided in association with a weakly-ordered multiprocessor system. Bach processor in the multiprocessor shares resources, and each shared resource has an associated lock within a locking device that provides support for synchronization between the multiple processors in the multiprocessor and the orderly sharing of the resources. A processor only has permission to access a resource when it owns the lock associated with that resource, and an attempt by a processor to own a lock requires only a single load operation, rather than a traditional atomic load followed by store, such that the processormore » only performs a read operation and the hardware locking device performs a subsequent write operation rather than the processor. A simple prefetching for non-contiguous data structures is also disclosed. A memory line is redefined so that in addition to the normal physical memory data, every line includes a pointer that is large enough to point to any other line in the memory, wherein the pointers to determine which memory line to prefetch rather than some other predictive algorithm. This enables hardware to effectively prefetch memory access patterns that are non-contiguous, but repetitive.« less

Location-Unbound Color-Shape Binding Representations in Visual Working Memory.

PubMed

Saiki, Jun

2016-02-01

The mechanism by which nonspatial features, such as color and shape, are bound in visual working memory, and the role of those features' location in their binding, remains unknown. In the current study, I modified a redundancy-gain paradigm to investigate these issues. A set of features was presented in a two-object memory display, followed by a single object probe. Participants judged whether the probe contained any features of the memory display, regardless of its location. Response time distributions revealed feature coactivation only when both features of a single object in the memory display appeared together in the probe, regardless of the response time benefit from the probe and memory objects sharing the same location. This finding suggests that a shared location is necessary in the formation of bound representations but unnecessary in their maintenance. Electroencephalography data showed that amplitude modulations reflecting location-unbound feature coactivation were different from those reflecting the location-sharing benefit, consistent with the behavioral finding that feature-location binding is unnecessary in the maintenance of color-shape binding. © The Author(s) 2015.

Shared reality in intergroup communication: Increasing the epistemic authority of an out-group audience.

PubMed

Echterhoff, Gerald; Kopietz, René; Higgins, E Tory

2017-06-01

Communicators typically tune messages to their audience's attitude. Such audience tuning biases communicators' memory for the topic toward the audience's attitude to the extent that they create a shared reality with the audience. To investigate shared reality in intergroup communication, we first established that a reduced memory bias after tuning messages to an out-group (vs. in-group) audience is a subtle index of communicators' denial of shared reality to that out-group audience (Experiments 1a and 1b). We then examined whether the audience-tuning memory bias might emerge when the out-group audience's epistemic authority is enhanced, either by increasing epistemic expertise concerning the communication topic or by creating epistemic consensus among members of a multiperson out-group audience. In Experiment 2, when Germans communicated to a Turkish audience with an attitude about a Turkish (vs. German) target, the audience-tuning memory bias appeared. In Experiment 3, when the audience of German communicators consisted of 3 Turks who all held the same attitude toward the target, the memory bias again appeared. The association between message valence and memory valence was consistently higher when the audience's epistemic authority was high (vs. low). An integrative analysis across all studies also suggested that the memory bias increases with increasing strength of epistemic inputs (epistemic expertise, epistemic consensus, and audience-tuned message production). The findings suggest novel ways of overcoming intergroup biases in intergroup relations. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Neural Global Pattern Similarity Underlies True and False Memories.

PubMed

Ye, Zhifang; Zhu, Bi; Zhuang, Liping; Lu, Zhonglin; Chen, Chuansheng; Xue, Gui

2016-06-22

The neural processes giving rise to human memory strength signals remain poorly understood. Inspired by formal computational models that posit a central role of global matching in memory strength, we tested a novel hypothesis that the strengths of both true and false memories arise from the global similarity of an item's neural activation pattern during retrieval to that of all the studied items during encoding (i.e., the encoding-retrieval neural global pattern similarity [ER-nGPS]). We revealed multiple ER-nGPS signals that carried distinct information and contributed differentially to true and false memories: Whereas the ER-nGPS in the parietal regions reflected semantic similarity and was scaled with the recognition strengths of both true and false memories, ER-nGPS in the visual cortex contributed solely to true memory. Moreover, ER-nGPS differences between the parietal and visual cortices were correlated with frontal monitoring processes. By combining computational and neuroimaging approaches, our results advance a mechanistic understanding of memory strength in recognition. What neural processes give rise to memory strength signals, and lead to our conscious feelings of familiarity? Using fMRI, we found that the memory strength of a given item depends not only on how it was encoded during learning, but also on the similarity of its neural representation with other studied items. The global neural matching signal, mainly in the parietal lobule, could account for the memory strengths of both studied and unstudied items. Interestingly, a different global matching signal, originated from the visual cortex, could distinguish true from false memories. The findings reveal multiple neural mechanisms underlying the memory strengths of events registered in the brain. Copyright © 2016 the authors 0270-6474/16/366792-11$15.00/0.

The Developmental Influence of Primary Memory Capacity on Working Memory and Academic Achievement

PubMed Central

2015-01-01

In this study, we investigate the development of primary memory capacity among children. Children between the ages of 5 and 8 completed 3 novel tasks (split span, interleaved lists, and a modified free-recall task) that measured primary memory by estimating the number of items in the focus of attention that could be spontaneously recalled in serial order. These tasks were calibrated against traditional measures of simple and complex span. Clear age-related changes in these primary memory estimates were observed. There were marked individual differences in primary memory capacity, but each novel measure was predictive of simple span performance. Among older children, each measure shared variance with reading and mathematics performance, whereas for younger children, the interleaved lists task was the strongest single predictor of academic ability. We argue that these novel tasks have considerable potential for the measurement of primary memory capacity and provide new, complementary ways of measuring the transient memory processes that predict academic performance. The interleaved lists task also shared features with interference control tasks, and our findings suggest that young children have a particular difficulty in resisting distraction and that variance in the ability to resist distraction is also shared with measures of educational attainment. PMID:26075630

The developmental influence of primary memory capacity on working memory and academic achievement.

PubMed

Hall, Debbora; Jarrold, Christopher; Towse, John N; Zarandi, Amy L

2015-08-01

In this study, we investigate the development of primary memory capacity among children. Children between the ages of 5 and 8 completed 3 novel tasks (split span, interleaved lists, and a modified free-recall task) that measured primary memory by estimating the number of items in the focus of attention that could be spontaneously recalled in serial order. These tasks were calibrated against traditional measures of simple and complex span. Clear age-related changes in these primary memory estimates were observed. There were marked individual differences in primary memory capacity, but each novel measure was predictive of simple span performance. Among older children, each measure shared variance with reading and mathematics performance, whereas for younger children, the interleaved lists task was the strongest single predictor of academic ability. We argue that these novel tasks have considerable potential for the measurement of primary memory capacity and provide new, complementary ways of measuring the transient memory processes that predict academic performance. The interleaved lists task also shared features with interference control tasks, and our findings suggest that young children have a particular difficulty in resisting distraction and that variance in the ability to resist distraction is also shared with measures of educational attainment. (c) 2015 APA, all rights reserved).

Conditional load and store in a shared memory

DOEpatents

Blumrich, Matthias A; Ohmacht, Martin

2015-02-03

A method, system and computer program product for implementing load-reserve and store-conditional instructions in a multi-processor computing system. The computing system includes a multitude of processor units and a shared memory cache, and each of the processor units has access to the memory cache. In one embodiment, the method comprises providing the memory cache with a series of reservation registers, and storing in these registers addresses reserved in the memory cache for the processor units as a result of issuing load-reserve requests. In this embodiment, when one of the processor units makes a request to store data in the memory cache using a store-conditional request, the reservation registers are checked to determine if an address in the memory cache is reserved for that processor unit. If an address in the memory cache is reserved for that processor, the data are stored at this address.

Performance Analysis of Multilevel Parallel Applications on Shared Memory Architectures

NASA Technical Reports Server (NTRS)

Biegel, Bryan A. (Technical Monitor); Jost, G.; Jin, H.; Labarta J.; Gimenez, J.; Caubet, J.

2003-01-01

Parallel programming paradigms include process level parallelism, thread level parallelization, and multilevel parallelism. This viewgraph presentation describes a detailed performance analysis of these paradigms for Shared Memory Architecture (SMA). This analysis uses the Paraver Performance Analysis System. The presentation includes diagrams of a flow of useful computations.

Measuring Transactiving Memory Systems Using Network Analysis

ERIC Educational Resources Information Center

King, Kylie Goodell

2017-01-01

Transactive memory systems (TMSs) describe the structures and processes that teams use to share information, work together, and accomplish shared goals. First introduced over three decades ago, TMSs have been measured in a variety of ways. This dissertation proposes the use of network analysis in measuring TMS. This is accomplished by describing…

Operator Influence of Unexploded Ordnance Sensor Technologies

DTIC Science & Technology

2007-03-01

chart display ActiveX control Mscomct2.dll – date/time display ActiveX control Pnpscr.dll – Systran SCRAMNet replicated shared memory device...response value database rgm_p2.dll – Phase 2 shared memory API and implementation Commercial components StripM.ocx – strip chart display ActiveX

Runtime support for parallelizing data mining algorithms

NASA Astrophysics Data System (ADS)

Jin, Ruoming; Agrawal, Gagan

2002-03-01

With recent technological advances, shared memory parallel machines have become more scalable, and offer large main memories and high bus bandwidths. They are emerging as good platforms for data warehousing and data mining. In this paper, we focus on shared memory parallelization of data mining algorithms. We have developed a series of techniques for parallelization of data mining algorithms, including full replication, full locking, fixed locking, optimized full locking, and cache-sensitive locking. Unlike previous work on shared memory parallelization of specific data mining algorithms, all of our techniques apply to a large number of common data mining algorithms. In addition, we propose a reduction-object based interface for specifying a data mining algorithm. We show how our runtime system can apply any of the technique we have developed starting from a common specification of the algorithm.

Concurrent working memory load can facilitate selective attention: evidence for specialized load.

PubMed

Park, Soojin; Kim, Min-Shik; Chun, Marvin M

2007-10-01

Load theory predicts that concurrent working memory load impairs selective attention and increases distractor interference (N. Lavie, A. Hirst, J. W. de Fockert, & E. Viding). Here, the authors present new evidence that the type of concurrent working memory load determines whether load impairs selective attention or not. Working memory load was paired with a same/different matching task that required focusing on targets while ignoring distractors. When working memory items shared the same limited-capacity processing mechanisms with targets in the matching task, distractor interference increased. However, when working memory items shared processing with distractors in the matching task, distractor interference decreased, facilitating target selection. A specialized load account is proposed to describe the dissociable effects of working memory load on selective processing depending on whether the load overlaps with targets or with distractors. (c) 2007 APA

Transactive memory systems scale for couples: development and validation

PubMed Central

Hewitt, Lauren Y.; Roberts, Lynne D.

2015-01-01

People in romantic relationships can develop shared memory systems by pooling their cognitive resources, allowing each person access to more information but with less cognitive effort. Research examining such memory systems in romantic couples largely focuses on remembering word lists or performing lab-based tasks, but these types of activities do not capture the processes underlying couples’ transactive memory systems, and may not be representative of the ways in which romantic couples use their shared memory systems in everyday life. We adapted an existing measure of transactive memory systems for use with romantic couples (TMSS-C), and conducted an initial validation study. In total, 397 participants who each identified as being a member of a romantic relationship of at least 3 months duration completed the study. The data provided a good fit to the anticipated three-factor structure of the components of couples’ transactive memory systems (specialization, credibility and coordination), and there was reasonable evidence of both convergent and divergent validity, as well as strong evidence of test–retest reliability across a 2-week period. The TMSS-C provides a valuable tool that can quickly and easily capture the underlying components of romantic couples’ transactive memory systems. It has potential to help us better understand this intriguing feature of romantic relationships, and how shared memory systems might be associated with other important features of romantic relationships. PMID:25999873

DMA shared byte counters in a parallel computer

DOEpatents

Chen, Dong; Gara, Alan G.; Heidelberger, Philip; Vranas, Pavlos

2010-04-06

A parallel computer system is constructed as a network of interconnected compute nodes. Each of the compute nodes includes at least one processor, a memory and a DMA engine. The DMA engine includes a processor interface for interfacing with the at least one processor, DMA logic, a memory interface for interfacing with the memory, a DMA network interface for interfacing with the network, injection and reception byte counters, injection and reception FIFO metadata, and status registers and control registers. The injection FIFOs maintain memory locations of the injection FIFO metadata memory locations including its current head and tail, and the reception FIFOs maintain the reception FIFO metadata memory locations including its current head and tail. The injection byte counters and reception byte counters may be shared between messages.

Division of attention as a function of the number of steps, visual shifts, and memory load

NASA Technical Reports Server (NTRS)

Chechile, R. A.; Butler, K.; Gutowski, W.; Palmer, E. A.

1986-01-01

The effects on divided attention of visual shifts and long-term memory retrieval during a monitoring task are considered. A concurrent vigilance task was standardized under all experimental conditions. The results show that subjects can perform nearly perfectly on all of the time-shared tasks if long-term memory retrieval is not required for monitoring. With the requirement of memory retrieval, however, there was a large decrease in accuracy for all of the time-shared activities. It was concluded that the attentional demand of longterm memory retrieval is appreciable (even for a well-learned motor sequence), and thus memory retrieval results in a sizable reduction in the capability of subjects to divide their attention. A selected bibliography on the divided attention literature is provided.

Global Neural Pattern Similarity as a Common Basis for Categorization and Recognition Memory

PubMed Central

Xue, Gui; Love, Bradley C.; Preston, Alison R.; Poldrack, Russell A.

2014-01-01

Familiarity, or memory strength, is a central construct in models of cognition. In previous categorization and long-term memory research, correlations have been found between psychological measures of memory strength and activation in the medial temporal lobes (MTLs), which suggests a common neural locus for memory strength. However, activation alone is insufficient for determining whether the same mechanisms underlie neural function across domains. Guided by mathematical models of categorization and long-term memory, we develop a theory and a method to test whether memory strength arises from the global similarity among neural representations. In human subjects, we find significant correlations between global similarity among activation patterns in the MTLs and both subsequent memory confidence in a recognition memory task and model-based measures of memory strength in a category learning task. Our work bridges formal cognitive theories and neuroscientific models by illustrating that the same global similarity computations underlie processing in multiple cognitive domains. Moreover, by establishing a link between neural similarity and psychological memory strength, our findings suggest that there may be an isomorphism between psychological and neural representational spaces that can be exploited to test cognitive theories at both the neural and behavioral levels. PMID:24872552

The development of GPU-based parallel PRNG for Monte Carlo applications in CUDA Fortran

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

Kargaran, Hamed, E-mail: h-kargaran@sbu.ac.ir; Minuchehr, Abdolhamid; Zolfaghari, Ahmad

The implementation of Monte Carlo simulation on the CUDA Fortran requires a fast random number generation with good statistical properties on GPU. In this study, a GPU-based parallel pseudo random number generator (GPPRNG) have been proposed to use in high performance computing systems. According to the type of GPU memory usage, GPU scheme is divided into two work modes including GLOBAL-MODE and SHARED-MODE. To generate parallel random numbers based on the independent sequence method, the combination of middle-square method and chaotic map along with the Xorshift PRNG have been employed. Implementation of our developed PPRNG on a single GPU showedmore » a speedup of 150x and 470x (with respect to the speed of PRNG on a single CPU core) for GLOBAL-MODE and SHARED-MODE, respectively. To evaluate the accuracy of our developed GPPRNG, its performance was compared to that of some other commercially available PPRNGs such as MATLAB, FORTRAN and Miller-Park algorithm through employing the specific standard tests. The results of this comparison showed that the developed GPPRNG in this study can be used as a fast and accurate tool for computational science applications.« less

Welcoming nora: a family event.

PubMed

Walsh, Allison J; Walsh, Paul R; Walsh, Jane M; Walsh, Gavin T

2011-01-01

In this column, Allison and Paul Walsh share the story of the birth of Nora, their third baby and their second child to be born at home. Allison and Paul share their individual memories of labor and birth. But their story is only part of the story of Nora's birth. Nora's birth was a family event, with Allison and Paul's other children very much part of the experience. Jane and Gavin share their own memories of their baby sister's birth.

Colouring in the Blanks: Memory Drawings of the 1990 Kuwait Invasion

ERIC Educational Resources Information Center

Pepin-Wakefield, Yvonne

2009-01-01

This study used drawing tasks to examine the similarities and differences between females and males who shared a collective traumatic event in early childhood. Could these childhood memories be recorded, measured, and compared for gender differences in drawings by young adults who had shared a similar experience as children? Exploration of this…

Functions of Memory Sharing and Mother-Child Reminiscing Behaviors: Individual and Cultural Variations

ERIC Educational Resources Information Center

Kulkofsky, Sarah; Wang, Qi; Koh, Jessie Bee Kim

2009-01-01

This study examined maternal beliefs about the functions of memory sharing and the relations between these beliefs and mother-child reminiscing behaviors in a cross-cultural context. Sixty-three European American and 47 Chinese mothers completed an open-ended questionnaire concerning their beliefs about the functions of parent-child memory…

Stillbirth and stigma: the spoiling and repair of multiple social identities.

PubMed

Brierley-Jones, Lyn; Crawley, Rosalind; Lomax, Samantha; Ayers, Susan

This study investigated mothers' experiences surrounding stillbirth in the United Kingdom, their memory making and sharing opportunities, and the effect these opportunities had on them. Qualitative data were generated from free text responses to open-ended questions. Thematic content analysis revealed that "stigma" was experienced by most women and Goffman's (1963) work on stigma was subsequently used as an analytical framework. Results suggest that stillbirth can spoil the identities of "patient," "mother," and "full citizen." Stigma was reported as arising from interactions with professionals, family, friends, work colleagues, and even casual acquaintances. Stillbirth produces common learning experiences often requiring "identity work" (Murphy, 2012). Memory making and sharing may be important in this work and further research is needed. Stigma can reduce the memory sharing opportunities for women after stillbirth and this may explain some of the differential mental health effects of memory making after stillbirth that is documented in the literature.

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.

A simple modern correctness condition for a space-based high-performance multiprocessor

NASA Technical Reports Server (NTRS)

Probst, David K.; Li, Hon F.

1992-01-01

A number of U.S. national programs, including space-based detection of ballistic missile launches, envisage putting significant computing power into space. Given sufficient progress in low-power VLSI, multichip-module packaging and liquid-cooling technologies, we will see design of high-performance multiprocessors for individual satellites. In very high speed implementations, performance depends critically on tolerating large latencies in interprocessor communication; without latency tolerance, performance is limited by the vastly differing time scales in processor and data-memory modules, including interconnect times. The modern approach to tolerating remote-communication cost in scalable, shared-memory multiprocessors is to use a multithreaded architecture, and alter the semantics of shared memory slightly, at the price of forcing the programmer either to reason about program correctness in a relaxed consistency model or to agree to program in a constrained style. The literature on multiprocessor correctness conditions has become increasingly complex, and sometimes confusing, which may hinder its practical application. We propose a simple modern correctness condition for a high-performance, shared-memory multiprocessor; the correctness condition is based on a simple interface between the multiprocessor architecture and a high-performance, shared-memory multiprocessor; the correctness condition is based on a simple interface between the multiprocessor architecture and the parallel programming system.

Brain Information Sharing During Visual Short-Term Memory Binding Yields a Memory Biomarker for Familial Alzheimer's Disease.

PubMed

Parra, Mario A; Mikulan, Ezequiel; Trujillo, Natalia; Sala, Sergio Della; Lopera, Francisco; Manes, Facundo; Starr, John; Ibanez, Agustin

2017-01-01

Alzheimer's disease (AD) as a disconnection syndrome which disrupts both brain information sharing and memory binding functions. The extent to which these two phenotypic expressions share pathophysiological mechanisms remains unknown. To unveil the electrophysiological correlates of integrative memory impairments in AD towards new memory biomarkers for its prodromal stages. Patients with 100% risk of familial AD (FAD) and healthy controls underwent assessment with the Visual Short-Term Memory binding test (VSTMBT) while we recorded their EEG. We applied a novel brain connectivity method (Weighted Symbolic Mutual Information) to EEG data. Patients showed significant deficits during the VSTMBT. A reduction of brain connectivity was observed during resting as well as during correct VSTM binding, particularly over frontal and posterior regions. An increase of connectivity was found during VSTM binding performance over central regions. While decreased connectivity was found in cases in more advanced stages of FAD, increased brain connectivity appeared in cases in earlier stages. Such altered patterns of task-related connectivity were found in 89% of the assessed patients. VSTM binding in the prodromal stages of FAD are associated to altered patterns of brain connectivity thus confirming the link between integrative memory deficits and impaired brain information sharing in prodromal FAD. While significant loss of brain connectivity seems to be a feature of the advanced stages of FAD increased brain connectivity characterizes its earlier stages. These findings are discussed in the light of recent proposals about the earliest pathophysiological mechanisms of AD and their clinical expression. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Parallelization and automatic data distribution for nuclear reactor simulations

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

Liebrock, L.M.

1997-07-01

Detailed attempts at realistic nuclear reactor simulations currently take many times real time to execute on high performance workstations. Even the fastest sequential machine can not run these simulations fast enough to ensure that the best corrective measure is used during a nuclear accident to prevent a minor malfunction from becoming a major catastrophe. Since sequential computers have nearly reached the speed of light barrier, these simulations will have to be run in parallel to make significant improvements in speed. In physical reactor plants, parallelism abounds. Fluids flow, controls change, and reactions occur in parallel with only adjacent components directlymore » affecting each other. These do not occur in the sequentialized manner, with global instantaneous effects, that is often used in simulators. Development of parallel algorithms that more closely approximate the real-world operation of a reactor may, in addition to speeding up the simulations, actually improve the accuracy and reliability of the predictions generated. Three types of parallel architecture (shared memory machines, distributed memory multicomputers, and distributed networks) are briefly reviewed as targets for parallelization of nuclear reactor simulation. Various parallelization models (loop-based model, shared memory model, functional model, data parallel model, and a combined functional and data parallel model) are discussed along with their advantages and disadvantages for nuclear reactor simulation. A variety of tools are introduced for each of the models. Emphasis is placed on the data parallel model as the primary focus for two-phase flow simulation. Tools to support data parallel programming for multiple component applications and special parallelization considerations are also discussed.« less

Decomposing the relationship between cognitive functioning and self-referent memory beliefs in older adulthood: What’s memory got to do with it?

PubMed Central

Payne, Brennan R.; Gross, Alden L.; Hill, Patrick L.; Parisi, Jeanine M.; Rebok, George W.; Stine-Morrow, Elizabeth A. L.

2018-01-01

With advancing age, episodic memory performance shows marked declines along with concurrent reports of lower subjective memory beliefs. Given that normative age-related declines in episodic memory co-occur with declines in other cognitive domains, we examined the relationship between memory beliefs and multiple domains of cognitive functioning. Confirmatory bi-factor structural equation models were used to parse the shared and independent variance among factors representing episodic memory, psychomotor speed, and executive reasoning in one large cohort study (Senior Odyssey, N = 462), and replicated using another large cohort of healthy older adults (ACTIVE, N = 2,802). Accounting for a general fluid cognitive functioning factor (comprised of the shared variance among measures of episodic memory, speed, and reasoning) attenuated the relationship between objective memory performance and subjective memory beliefs in both samples. Moreover, the general cognitive functioning factor was the strongest predictor of memory beliefs in both samples. These findings are consistent with the notion that dispositional memory beliefs may reflect perceptions of cognition more broadly. This may be one reason why memory beliefs have broad predictive validity for interventions that target fluid cognitive ability. PMID:27685541

Decomposing the relationship between cognitive functioning and self-referent memory beliefs in older adulthood: what's memory got to do with it?

PubMed

Payne, Brennan R; Gross, Alden L; Hill, Patrick L; Parisi, Jeanine M; Rebok, George W; Stine-Morrow, Elizabeth A L

2017-07-01

With advancing age, episodic memory performance shows marked declines along with concurrent reports of lower subjective memory beliefs. Given that normative age-related declines in episodic memory co-occur with declines in other cognitive domains, we examined the relationship between memory beliefs and multiple domains of cognitive functioning. Confirmatory bi-factor structural equation models were used to parse the shared and independent variance among factors representing episodic memory, psychomotor speed, and executive reasoning in one large cohort study (Senior Odyssey, N = 462), and replicated using another large cohort of healthy older adults (ACTIVE, N = 2802). Accounting for a general fluid cognitive functioning factor (comprised of the shared variance among measures of episodic memory, speed, and reasoning) attenuated the relationship between objective memory performance and subjective memory beliefs in both samples. Moreover, the general cognitive functioning factor was the strongest predictor of memory beliefs in both samples. These findings are consistent with the notion that dispositional memory beliefs may reflect perceptions of cognition more broadly. This may be one reason why memory beliefs have broad predictive validity for interventions that target fluid cognitive ability.

Method for prefetching non-contiguous data structures

DOEpatents

Blumrich, Matthias A [Ridgefield, CT; Chen, Dong [Croton On Hudson, NY; Coteus, Paul W [Yorktown Heights, NY; Gara, Alan G [Mount Kisco, NY; Giampapa, Mark E [Irvington, NY; Heidelberger, Philip [Cortlandt Manor, NY; Hoenicke, Dirk [Ossining, NY; Ohmacht, Martin [Brewster, NY; Steinmacher-Burow, Burkhard D [Mount Kisco, NY; Takken, Todd E [Mount Kisco, NY; Vranas, Pavlos M [Bedford Hills, NY

2009-05-05

A low latency memory system access is provided in association with a weakly-ordered multiprocessor system. Each processor in the multiprocessor shares resources, and each shared resource has an associated lock within a locking device that provides support for synchronization between the multiple processors in the multiprocessor and the orderly sharing of the resources. A processor only has permission to access a resource when it owns the lock associated with that resource, and an attempt by a processor to own a lock requires only a single load operation, rather than a traditional atomic load followed by store, such that the processor only performs a read operation and the hardware locking device performs a subsequent write operation rather than the processor. A simple perfecting for non-contiguous data structures is also disclosed. A memory line is redefined so that in addition to the normal physical memory data, every line includes a pointer that is large enough to point to any other line in the memory, wherein the pointers to determine which memory line to prefect rather than some other predictive algorithm. This enables hardware to effectively prefect memory access patterns that are non-contiguous, but repetitive.

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.

A shared resource between declarative memory and motor memory.

PubMed

Keisler, Aysha; Shadmehr, Reza

2010-11-03

The neural systems that support motor adaptation in humans are thought to be distinct from those that support the declarative system. Yet, during motor adaptation changes in motor commands are supported by a fast adaptive process that has important properties (rapid learning, fast decay) that are usually associated with the declarative system. The fast process can be contrasted to a slow adaptive process that also supports motor memory, but learns gradually and shows resistance to forgetting. Here we show that after people stop performing a motor task, the fast motor memory can be disrupted by a task that engages declarative memory, but the slow motor memory is immune from this interference. Furthermore, we find that the fast/declarative component plays a major role in the consolidation of the slow motor memory. Because of the competitive nature of declarative and nondeclarative memory during consolidation, impairment of the fast/declarative component leads to improvements in the slow/nondeclarative component. Therefore, the fast process that supports formation of motor memory is not only neurally distinct from the slow process, but it shares critical resources with the declarative memory system.

A shared resource between declarative memory and motor memory

PubMed Central

Keisler, Aysha; Shadmehr, Reza

2010-01-01

The neural systems that support motor adaptation in humans are thought to be distinct from those that support the declarative system. Yet, during motor adaptation changes in motor commands are supported by a fast adaptive process that has important properties (rapid learning, fast decay) that are usually associated with the declarative system. The fast process can be contrasted to a slow adaptive process that also supports motor memory, but learns gradually and shows resistance to forgetting. Here we show that after people stop performing a motor task, the fast motor memory can be disrupted by a task that engages declarative memory, but the slow motor memory is immune from this interference. Furthermore, we find that the fast/declarative component plays a major role in the consolidation of the slow motor memory. Because of the competitive nature of declarative and non-declarative memory during consolidation, impairment of the fast/declarative component leads to improvements in the slow/non-declarative component. Therefore, the fast process that supports formation of motor memory is not only neurally distinct from the slow process, but it shares critical resources with the declarative memory system. PMID:21048140

Discrete-Slots Models of Visual Working-Memory Response Times

PubMed Central

Donkin, Christopher; Nosofsky, Robert M.; Gold, Jason M.; Shiffrin, Richard M.

2014-01-01

Much recent research has aimed to establish whether visual working memory (WM) is better characterized by a limited number of discrete all-or-none slots or by a continuous sharing of memory resources. To date, however, researchers have not considered the response-time (RT) predictions of discrete-slots versus shared-resources models. To complement the past research in this field, we formalize a family of mixed-state, discrete-slots models for explaining choice and RTs in tasks of visual WM change detection. In the tasks under investigation, a small set of visual items is presented, followed by a test item in 1 of the studied positions for which a change judgment must be made. According to the models, if the studied item in that position is retained in 1 of the discrete slots, then a memory-based evidence-accumulation process determines the choice and the RT; if the studied item in that position is missing, then a guessing-based accumulation process operates. Observed RT distributions are therefore theorized to arise as probabilistic mixtures of the memory-based and guessing distributions. We formalize an analogous set of continuous shared-resources models. The model classes are tested on individual subjects with both qualitative contrasts and quantitative fits to RT-distribution data. The discrete-slots models provide much better qualitative and quantitative accounts of the RT and choice data than do the shared-resources models, although there is some evidence for “slots plus resources” when memory set size is very small. PMID:24015956

Transient Global Amnesia

MedlinePlus

... global amnesia is a sudden, temporary episode of memory loss that can't be attributed to a ... know well. But that doesn't make your memory loss less disturbing. Fortunately, transient global amnesia is ...

Global neural pattern similarity as a common basis for categorization and recognition memory.

PubMed

Davis, Tyler; Xue, Gui; Love, Bradley C; Preston, Alison R; Poldrack, Russell A

2014-05-28

Familiarity, or memory strength, is a central construct in models of cognition. In previous categorization and long-term memory research, correlations have been found between psychological measures of memory strength and activation in the medial temporal lobes (MTLs), which suggests a common neural locus for memory strength. However, activation alone is insufficient for determining whether the same mechanisms underlie neural function across domains. Guided by mathematical models of categorization and long-term memory, we develop a theory and a method to test whether memory strength arises from the global similarity among neural representations. In human subjects, we find significant correlations between global similarity among activation patterns in the MTLs and both subsequent memory confidence in a recognition memory task and model-based measures of memory strength in a category learning task. Our work bridges formal cognitive theories and neuroscientific models by illustrating that the same global similarity computations underlie processing in multiple cognitive domains. Moreover, by establishing a link between neural similarity and psychological memory strength, our findings suggest that there may be an isomorphism between psychological and neural representational spaces that can be exploited to test cognitive theories at both the neural and behavioral levels. Copyright © 2014 the authors 0270-6474/14/347472-13$15.00/0.

Shared Representations in Language Processing and Verbal Short-Term Memory: The Case of Grammatical Gender

ERIC Educational Resources Information Center

Schweppe, Judith; Rummer, Ralf

2007-01-01

The general idea of language-based accounts of short-term memory is that retention of linguistic materials is based on representations within the language processing system. In the present sentence recall study, we address the question whether the assumption of shared representations holds for morphosyntactic information (here: grammatical gender…

The Precategorical Nature of Visual Short-Term Memory

ERIC Educational Resources Information Center

Quinlan, Philip T.; Cohen, Dale J.

2016-01-01

We conducted a series of recognition experiments that assessed whether visual short-term memory (VSTM) is sensitive to shared category membership of to-be-remembered (tbr) images of common objects. In Experiment 1 some of the tbr items shared the same basic level category (e.g., hand axe): Such items were no better retained than others. In the…

Fault tolerant onboard packet switch architecture for communication satellites: Shared memory per beam approach

NASA Technical Reports Server (NTRS)

Shalkhauser, Mary JO; Quintana, Jorge A.; Soni, Nitin J.

1994-01-01

The NASA Lewis Research Center is developing a multichannel communication signal processing satellite (MCSPS) system which will provide low data rate, direct to user, commercial communications services. The focus of current space segment developments is a flexible, high-throughput, fault tolerant onboard information switching processor. This information switching processor (ISP) is a destination-directed packet switch which performs both space and time switching to route user information among numerous user ground terminals. Through both industry study contracts and in-house investigations, several packet switching architectures were examined. A contention-free approach, the shared memory per beam architecture, was selected for implementation. The shared memory per beam architecture, fault tolerance insertion, implementation, and demonstration plans are described.

The performance of disk arrays in shared-memory database machines

NASA Technical Reports Server (NTRS)

Katz, Randy H.; Hong, Wei

1993-01-01

In this paper, we examine how disk arrays and shared memory multiprocessors lead to an effective method for constructing database machines for general-purpose complex query processing. We show that disk arrays can lead to cost-effective storage systems if they are configured from suitably small formfactor disk drives. We introduce the storage system metric data temperature as a way to evaluate how well a disk configuration can sustain its workload, and we show that disk arrays can sustain the same data temperature as a more expensive mirrored-disk configuration. We use the metric to evaluate the performance of disk arrays in XPRS, an operational shared-memory multiprocessor database system being developed at the University of California, Berkeley.

77 FR 18266 - Meeting of the Department of Justice Global Justice Information Sharing Initiative Federal...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-27

... Department of Justice Global Justice Information Sharing Initiative Federal Advisory Committee AGENCY: Office... meeting of the Department of Justice (DOJ) Global Justice Information Sharing Initiative (Global) Federal Advisory Committee (GAC) to discuss the Global Initiative, as described at www.it.ojp.gov/global . DATES...

A lifelong journey of moving beyond wartime trauma for survivors from Hiroshima and Pearl Harbor.

PubMed

Liehr, Patricia; Nishimura, Chie; Ito, Mio; Wands, Lisa Marie; Takahashi, Ryutaro

2011-01-01

This study examines 51 stories of health, shared by people who survived the wartime trauma of Hiroshima and Pearl Harbor, seeking to identify turning points that moved participants along over their lifetime. The central turning point for Hiroshima survivors was "becoming Hibabusha (A-bomb survivor)" and for Pearl Harbor survivors was "honoring the memory and setting it aside." Wartime trauma was permanently integrated into survivors' histories, surfacing steadily over decades for Hiroshima survivors and intermittently over decades for Pearl Harbor survivors. Regardless of experience or nationality, participants moved through wartime trauma by connecting with others, pursuing personal and global peace.

Optical memories in digital computing

NASA Technical Reports Server (NTRS)

Alford, C. O.; Gaylord, T. K.

1979-01-01

High capacity optical memories with relatively-high data-transfer rate and multiport simultaneous access capability may serve as basis for new computer architectures. Several computer structures that might profitably use memories are: a) simultaneous record-access system, b) simultaneously-shared memory computer system, and c) parallel digital processing structure.

Reader set encoding for directory of shared cache memory in multiprocessor system

DOEpatents

Ahn, Dnaiel; Ceze, Luis H.; Gara, Alan; Ohmacht, Martin; Xiaotong, Zhuang

2014-06-10

In a parallel processing system with speculative execution, conflict checking occurs in a directory lookup of a cache memory that is shared by all processors. In each case, the same physical memory address will map to the same set of that cache, no matter which processor originated that access. The directory includes a dynamic reader set encoding, indicating what speculative threads have read a particular line. This reader set encoding is used in conflict checking. A bitset encoding is used to specify particular threads that have read the line.

Insights on consciousness from taste memory research.

PubMed

Gallo, Milagros

2016-01-01

Taste research in rodents supports the relevance of memory in order to determine the content of consciousness by modifying both taste perception and later action. Associated with this issue is the fact that taste and visual modalities share anatomical circuits traditionally related to conscious memory. This challenges the view of taste memory as a type of non-declarative unconscious memory.

Investigating Ground Swarm Robotics Using Agent Based Simulation

DTIC Science & Technology

2006-12-01

Incorporation of virtual pheromones as a shared memory map is modeled as an additional capability that is found to enhance the robustness and reliability of the...virtual pheromones as a shared memory map is modeled as an additional capability that is found to enhance the robustness and reliability of the swarm... PHEROMONES .......................................... 42 1. Repel Friends under Inorganic SA.................................................. 45 2. Max

Centrally managed unified shared virtual address space

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

Wilkes, John

Systems, apparatuses, and methods for managing a unified shared virtual address space. A host may execute system software and manage a plurality of nodes coupled to the host. The host may send work tasks to the nodes, and for each node, the host may externally manage the node's view of the system's virtual address space. Each node may have a central processing unit (CPU) style memory management unit (MMU) with an internal translation lookaside buffer (TLB). In one embodiment, the host may be coupled to a given node via an input/output memory management unit (IOMMU) interface, where the IOMMU frontendmore » interface shares the TLB with the given node's MMU. In another embodiment, the host may control the given node's view of virtual address space via memory-mapped control registers.« less

Attention and Visuospatial Working Memory Share the Same Processing Resources

PubMed Central

Feng, Jing; Pratt, Jay; Spence, Ian

2012-01-01

Attention and visuospatial working memory (VWM) share very similar characteristics; both have the same upper bound of about four items in capacity and they recruit overlapping brain regions. We examined whether both attention and VWM share the same processing resources using a novel dual-task costs approach based on a load-varying dual-task technique. With sufficiently large loads on attention and VWM, considerable interference between the two processes was observed. A further load increase on either process produced reciprocal increases in interference on both processes, indicating that attention and VWM share common resources. More critically, comparison among four experiments on the reciprocal interference effects, as measured by the dual-task costs, demonstrates no significant contribution from additional processing other than the shared processes. These results support the notion that attention and VWM share the same processing resources. PMID:22529826

System and method for memory allocation in a multiclass memory system

DOEpatents

Loh, Gabriel; Meswani, Mitesh; Ignatowski, Michael; Nutter, Mark

2016-06-28

A system for memory allocation in a multiclass memory system includes a processor coupleable to a plurality of memories sharing a unified memory address space, and a library store to store a library of software functions. The processor identifies a type of a data structure in response to a memory allocation function call to the library for allocating memory to the data structure. Using the library, the processor allocates portions of the data structure among multiple memories of the multiclass memory system based on the type of the data structure.

Flexible language constructs for large parallel programs

NASA Technical Reports Server (NTRS)

Rosing, Matthew; Schnabel, Robert

1993-01-01

The goal of the research described is to develop flexible language constructs for writing large data parallel numerical programs for distributed memory (MIMD) multiprocessors. Previously, several models have been developed to support synchronization and communication. Models for global synchronization include SIMD (Single Instruction Multiple Data), SPMD (Single Program Multiple Data), and sequential programs annotated with data distribution statements. The two primary models for communication include implicit communication based on shared memory and explicit communication based on messages. None of these models by themselves seem sufficient to permit the natural and efficient expression of the variety of algorithms that occur in large scientific computations. An overview of a new language that combines many of these programming models in a clean manner is given. This is done in a modular fashion such that different models can be combined to support large programs. Within a module, the selection of a model depends on the algorithm and its efficiency requirements. An overview of the language and discussion of some of the critical implementation details is given.

Ultrahigh-order Maxwell solver with extreme scalability for electromagnetic PIC simulations of plasmas

NASA Astrophysics Data System (ADS)

Vincenti, Henri; Vay, Jean-Luc

2018-07-01

The advent of massively parallel supercomputers, with their distributed-memory technology using many processing units, has favored the development of highly-scalable local low-order solvers at the expense of harder-to-scale global very high-order spectral methods. Indeed, FFT-based methods, which were very popular on shared memory computers, have been largely replaced by finite-difference (FD) methods for the solution of many problems, including plasmas simulations with electromagnetic Particle-In-Cell methods. For some problems, such as the modeling of so-called "plasma mirrors" for the generation of high-energy particles and ultra-short radiations, we have shown that the inaccuracies of standard FD-based PIC methods prevent the modeling on present supercomputers at sufficient accuracy. We demonstrate here that a new method, based on the use of local FFTs, enables ultrahigh-order accuracy with unprecedented scalability, and thus for the first time the accurate modeling of plasma mirrors in 3D.

A Formal Model of Capacity Limits in Working Memory

ERIC Educational Resources Information Center

Oberauer, Klaus; Kliegl, Reinhold

2006-01-01

A mathematical model of working-memory capacity limits is proposed on the key assumption of mutual interference between items in working memory. Interference is assumed to arise from overwriting of features shared by these items. The model was fit to time-accuracy data of memory-updating tasks from four experiments using nonlinear mixed effect…

Ordering of guarded and unguarded stores for no-sync I/O

DOEpatents

Gara, Alan; Ohmacht, Martin

2013-06-25

A parallel computing system processes at least one store instruction. A first processor core issues a store instruction. A first queue, associated with the first processor core, stores the store instruction. A second queue, associated with a first local cache memory device of the first processor core, stores the store instruction. The first processor core updates first data in the first local cache memory device according to the store instruction. The third queue, associated with at least one shared cache memory device, stores the store instruction. The first processor core invalidates second data, associated with the store instruction, in the at least one shared cache memory. The first processor core invalidates third data, associated with the store instruction, in other local cache memory devices of other processor cores. The first processor core flushing only the first queue.

Explicit time integration of finite element models on a vectorized, concurrent computer with shared memory

NASA Technical Reports Server (NTRS)

Gilbertsen, Noreen D.; Belytschko, Ted

1990-01-01

The implementation of a nonlinear explicit program on a vectorized, concurrent computer with shared memory is described and studied. The conflict between vectorization and concurrency is described and some guidelines are given for optimal block sizes. Several example problems are summarized to illustrate the types of speed-ups which can be achieved by reprogramming as compared to compiler optimization.

LU Factorization with Partial Pivoting for a Multi-CPU, Multi-GPU Shared Memory System

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

Kurzak, Jakub; Luszczek, Pitior; Faverge, Mathieu

2012-03-01

LU factorization with partial pivoting is a canonical numerical procedure and the main component of the High Performance LINPACK benchmark. This article presents an implementation of the algorithm for a hybrid, shared memory, system with standard CPU cores and GPU accelerators. Performance in excess of one TeraFLOPS is achieved using four AMD Magny Cours CPUs and four NVIDIA Fermi GPUs.

Neural Mechanisms of Interference Control Underlie the Relationship between Fluid Intelligence and Working Memory Span

ERIC Educational Resources Information Center

Burgess, Gregory C.; Gray, Jeremy R.; Conway, Andrew R. A.; Braver, Todd S.

2011-01-01

Fluid intelligence (gF) and working memory (WM) span predict success in demanding cognitive situations. Recent studies show that much of the variance in gF and WM span is shared, suggesting common neural mechanisms. This study provides a direct investigation of the degree to which shared variance in gF and WM span can be explained by neural…

What Multilevel Parallel Programs do when you are not Watching: A Performance Analysis Case Study Comparing MPI/OpenMP, MLP, and Nested OpenMP

NASA Technical Reports Server (NTRS)

Jost, Gabriele; Labarta, Jesus; Gimenez, Judit

2004-01-01

With the current trend in parallel computer architectures towards clusters of shared memory symmetric multi-processors, parallel programming techniques have evolved that support parallelism beyond a single level. When comparing the performance of applications based on different programming paradigms, it is important to differentiate between the influence of the programming model itself and other factors, such as implementation specific behavior of the operating system (OS) or architectural issues. Rewriting-a large scientific application in order to employ a new programming paradigms is usually a time consuming and error prone task. Before embarking on such an endeavor it is important to determine that there is really a gain that would not be possible with the current implementation. A detailed performance analysis is crucial to clarify these issues. The multilevel programming paradigms considered in this study are hybrid MPI/OpenMP, MLP, and nested OpenMP. The hybrid MPI/OpenMP approach is based on using MPI [7] for the coarse grained parallelization and OpenMP [9] for fine grained loop level parallelism. The MPI programming paradigm assumes a private address space for each process. Data is transferred by explicitly exchanging messages via calls to the MPI library. This model was originally designed for distributed memory architectures but is also suitable for shared memory systems. The second paradigm under consideration is MLP which was developed by Taft. The approach is similar to MPi/OpenMP, using a mix of coarse grain process level parallelization and loop level OpenMP parallelization. As it is the case with MPI, a private address space is assumed for each process. The MLP approach was developed for ccNUMA architectures and explicitly takes advantage of the availability of shared memory. A shared memory arena which is accessible by all processes is required. Communication is done by reading from and writing to the shared memory.

Audience-tuning effects on memory: the role of shared reality.

PubMed

Echterhoff, Gerald; Higgins, E Tory; Groll, Stephan

2005-09-01

After tuning to an audience, communicators' own memories for the topic often reflect the biased view expressed in their messages. Three studies examined explanations for this bias. Memories for a target person were biased when feedback signaled the audience's successful identification of the target but not after failed identification (Experiment 1). Whereas communicators tuning to an in-group audience exhibited the bias, communicators tuning to an out-group audience did not (Experiment 2). These differences did not depend on communicators' mood but were mediated by communicators' trust in their audience's judgment about other people (Experiments 2 and 3). Message and memory were more closely associated for high than for low trusters. Apparently, audience-tuning effects depend on the communicators' experience of a shared reality.

Rapid solution of large-scale systems of equations

NASA Technical Reports Server (NTRS)

Storaasli, Olaf O.

1994-01-01

The analysis and design of complex aerospace structures requires the rapid solution of large systems of linear and nonlinear equations, eigenvalue extraction for buckling, vibration and flutter modes, structural optimization and design sensitivity calculation. Computers with multiple processors and vector capabilities can offer substantial computational advantages over traditional scalar computer for these analyses. These computers fall into two categories: shared memory computers and distributed memory computers. This presentation covers general-purpose, highly efficient algorithms for generation/assembly or element matrices, solution of systems of linear and nonlinear equations, eigenvalue and design sensitivity analysis and optimization. All algorithms are coded in FORTRAN for shared memory computers and many are adapted to distributed memory computers. The capability and numerical performance of these algorithms will be addressed.

Examining age-related shared variance between face cognition, vision, and self-reported physical health: a test of the common cause hypothesis for social cognition

PubMed Central

Olderbak, Sally; Hildebrandt, Andrea; Wilhelm, Oliver

2015-01-01

The shared decline in cognitive abilities, sensory functions (e.g., vision and hearing), and physical health with increasing age is well documented with some research attributing this shared age-related decline to a single common cause (e.g., aging brain). We evaluate the extent to which the common cause hypothesis predicts associations between vision and physical health with social cognition abilities specifically face perception and face memory. Based on a sample of 443 adults (17–88 years old), we test a series of structural equation models, including Multiple Indicator Multiple Cause (MIMIC) models, and estimate the extent to which vision and self-reported physical health are related to face perception and face memory through a common factor, before and after controlling for their fluid cognitive component and the linear effects of age. Results suggest significant shared variance amongst these constructs, with a common factor explaining some, but not all, of the shared age-related variance. Also, we found that the relations of face perception, but not face memory, with vision and physical health could be completely explained by fluid cognition. Overall, results suggest that a single common cause explains most, but not all age-related shared variance with domain specific aging mechanisms evident. PMID:26321998

Solutions and debugging for data consistency in multiprocessors with noncoherent caches

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

Bernstein, D.; Mendelson, B.; Breternitz, M. Jr.

1995-02-01

We analyze two important problems that arise in shared-memory multiprocessor systems. The stale data problem involves ensuring that data items in local memory of individual processors are current, independent of writes done by other processors. False sharing occurs when two processors have copies of the same shared data block but update different portions of the block. The false sharing problem involves guaranteeing that subsequent writes are properly combined. In modern architectures these problems are usually solved in hardware, by exploiting mechanisms for hardware controlled cache consistency. This leads to more expensive and nonscalable designs. Therefore, we are concentrating on softwaremore » methods for ensuring cache consistency that would allow for affordable and scalable multiprocessing systems. Unfortunately, providing software control is nontrivial, both for the compiler writer and for the application programmer. For this reason we are developing a debugging environment that will facilitate the development of compiler-based techniques and will help the programmer to tune his or her application using explicit cache management mechanisms. We extend the notion of a race condition for IBM Shared Memory System POWER/4, taking into consideration its noncoherent caches, and propose techniques for detection of false sharing problems. Identification of the stale data problem is discussed as well, and solutions are suggested.« less

Automatic Generation of OpenMP Directives and Its Application to Computational Fluid Dynamics Codes

NASA Technical Reports Server (NTRS)

Yan, Jerry; Jin, Haoqiang; Frumkin, Michael; Yan, Jerry (Technical Monitor)

2000-01-01

The shared-memory programming model is a very effective way to achieve parallelism on shared memory parallel computers. As great progress was made in hardware and software technologies, performance of parallel programs with compiler directives has demonstrated large improvement. The introduction of OpenMP directives, the industrial standard for shared-memory programming, has minimized the issue of portability. In this study, we have extended CAPTools, a computer-aided parallelization toolkit, to automatically generate OpenMP-based parallel programs with nominal user assistance. We outline techniques used in the implementation of the tool and discuss the application of this tool on the NAS Parallel Benchmarks and several computational fluid dynamics codes. This work demonstrates the great potential of using the tool to quickly port parallel programs and also achieve good performance that exceeds some of the commercial tools.

Static Memory Deduplication for Performance Optimization in Cloud Computing.

PubMed

Jia, Gangyong; Han, Guangjie; Wang, Hao; Yang, Xuan

2017-04-27

In a cloud computing environment, the number of virtual machines (VMs) on a single physical server and the number of applications running on each VM are continuously growing. This has led to an enormous increase in the demand of memory capacity and subsequent increase in the energy consumption in the cloud. Lack of enough memory has become a major bottleneck for scalability and performance of virtualization interfaces in cloud computing. To address this problem, memory deduplication techniques which reduce memory demand through page sharing are being adopted. However, such techniques suffer from overheads in terms of number of online comparisons required for the memory deduplication. In this paper, we propose a static memory deduplication (SMD) technique which can reduce memory capacity requirement and provide performance optimization in cloud computing. The main innovation of SMD is that the process of page detection is performed offline, thus potentially reducing the performance cost, especially in terms of response time. In SMD, page comparisons are restricted to the code segment, which has the highest shared content. Our experimental results show that SMD efficiently reduces memory capacity requirement and improves performance. We demonstrate that, compared to other approaches, the cost in terms of the response time is negligible.

Static Memory Deduplication for Performance Optimization in Cloud Computing

PubMed Central

Jia, Gangyong; Han, Guangjie; Wang, Hao; Yang, Xuan

2017-01-01

In a cloud computing environment, the number of virtual machines (VMs) on a single physical server and the number of applications running on each VM are continuously growing. This has led to an enormous increase in the demand of memory capacity and subsequent increase in the energy consumption in the cloud. Lack of enough memory has become a major bottleneck for scalability and performance of virtualization interfaces in cloud computing. To address this problem, memory deduplication techniques which reduce memory demand through page sharing are being adopted. However, such techniques suffer from overheads in terms of number of online comparisons required for the memory deduplication. In this paper, we propose a static memory deduplication (SMD) technique which can reduce memory capacity requirement and provide performance optimization in cloud computing. The main innovation of SMD is that the process of page detection is performed offline, thus potentially reducing the performance cost, especially in terms of response time. In SMD, page comparisons are restricted to the code segment, which has the highest shared content. Our experimental results show that SMD efficiently reduces memory capacity requirement and improves performance. We demonstrate that, compared to other approaches, the cost in terms of the response time is negligible. PMID:28448434

78 FR 17232 - Meeting of the Global Justice Information Sharing Initiative Federal Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-20

... DEPARTMENT OF JUSTICE Office of Justice Programs [OJP (BJA) Docket No. 1616] Meeting of the Global Justice Information Sharing Initiative Federal Advisory Committee AGENCY: Office of Justice Programs (OJP... Information Sharing Initiative (Global) Federal Advisory Committee (GAC) to discuss the Global Initiative, as...

General object recognition is specific: Evidence from novel and familiar objects.

PubMed

Richler, Jennifer J; Wilmer, Jeremy B; Gauthier, Isabel

2017-09-01

In tests of object recognition, individual differences typically correlate modestly but nontrivially across familiar categories (e.g. cars, faces, shoes, birds, mushrooms). In theory, these correlations could reflect either global, non-specific mechanisms, such as general intelligence (IQ), or more specific mechanisms. Here, we introduce two separate methods for effectively capturing category-general performance variation, one that uses novel objects and one that uses familiar objects. In each case, we show that category-general performance variance is unrelated to IQ, thereby implicating more specific mechanisms. The first approach examines three newly developed novel object memory tests (NOMTs). We predicted that NOMTs would exhibit more shared, category-general variance than familiar object memory tests (FOMTs) because novel objects, unlike familiar objects, lack category-specific environmental influences (e.g. exposure to car magazines or botany classes). This prediction held, and remarkably, virtually none of the substantial shared variance among NOMTs was explained by IQ. Also, while NOMTs correlated nontrivially with two FOMTs (faces, cars), these correlations were smaller than among NOMTs and no larger than between the face and car tests themselves, suggesting that the category-general variance captured by NOMTs is specific not only relative to IQ, but also, to some degree, relative to both face and car recognition. The second approach averaged performance across multiple FOMTs, which we predicted would increase category-general variance by averaging out category-specific factors. This prediction held, and as with NOMTs, virtually none of the shared variance among FOMTs was explained by IQ. Overall, these results support the existence of object recognition mechanisms that, though category-general, are specific relative to IQ and substantially separable from face and car recognition. They also add sensitive, well-normed NOMTs to the tools available to study object recognition. Copyright © 2017 Elsevier B.V. All rights reserved.

Scheduling for Locality in Shared-Memory Multiprocessors

DTIC Science & Technology

1993-05-01

Submitted in Partial Fulfillment of the Requirements for the Degree ’)iIC Q(JALfryT INSPECTED 5 DOCTOR OF PHILOSOPHY I Accesion For Supervised by NTIS CRAM... architecture on parallel program performance, explain the implications of this trend on popular parallel programming models, and propose system software to 0...decomoosition and scheduling algorithms. I. SUIUECT TERMS IS. NUMBER OF PAGES shared-memory multiprocessors; architecture trends; loop 110 scheduling

Advanced Development of Certified OS Kernels

DTIC Science & Technology

2015-06-01

It provides an infrastructure to map a physical page into multiple processes’ page maps in different address spaces. Their ownership mechanism ensures...of their shared memory infrastructure . Trap module The trap module specifies the behaviors of exception handlers and mCertiKOS system calls. In...layers), 1 pm for the shared memory infrastructure (3 layers), 3.5 pm for the thread management (10 layers), 1 pm for the process management (4 layers

6 DOF Nonlinear AUV Simulation Toolbox

DTIC Science & Technology

1997-01-01

is to supply a flexible 3D -simulation platform for motion visualization, in-lab debugging and testing of mission-specific strategies as well as those...Explorer are modular designed [Smith] in order to cut time and cost for vehicle recontlguration. A flexible 3D -simulation platform is desired to... 3D models. Current implemented modules include a nonlinear dynamic model for the OEX, shared memory and semaphore manager tools, shared memory monitor

Targeted Memory Reactivation during Sleep Adaptively Promotes the Strengthening or Weakening of Overlapping Memories.

PubMed

Oyarzún, Javiera P; Morís, Joaquín; Luque, David; de Diego-Balaguer, Ruth; Fuentemilla, Lluís

2017-08-09

System memory consolidation is conceptualized as an active process whereby newly encoded memory representations are strengthened through selective memory reactivation during sleep. However, our learning experience is highly overlapping in content (i.e., shares common elements), and memories of these events are organized in an intricate network of overlapping associated events. It remains to be explored whether and how selective memory reactivation during sleep has an impact on these overlapping memories acquired during awake time. Here, we test in a group of adult women and men the prediction that selective memory reactivation during sleep entails the reactivation of associated events and that this may lead the brain to adaptively regulate whether these associated memories are strengthened or pruned from memory networks on the basis of their relative associative strength with the shared element. Our findings demonstrate the existence of efficient regulatory neural mechanisms governing how complex memory networks are shaped during sleep as a function of their associative memory strength. SIGNIFICANCE STATEMENT Numerous studies have demonstrated that system memory consolidation is an active, selective, and sleep-dependent process in which only subsets of new memories become stabilized through their reactivation. However, the learning experience is highly overlapping in content and thus events are encoded in an intricate network of related memories. It remains to be explored whether and how memory reactivation has an impact on overlapping memories acquired during awake time. Here, we show that sleep memory reactivation promotes strengthening and weakening of overlapping memories based on their associative memory strength. These results suggest the existence of an efficient regulatory neural mechanism that avoids the formation of cluttered memory representation of multiple events and promotes stabilization of complex memory networks. Copyright © 2017 the authors 0270-6474/17/377748-11$15.00/0.

Parallel algorithms for boundary value problems

NASA Technical Reports Server (NTRS)

Lin, Avi

1990-01-01

A general approach to solve boundary value problems numerically in a parallel environment is discussed. The basic algorithm consists of two steps: the local step where all the P available processors work in parallel, and the global step where one processor solves a tridiagonal linear system of the order P. The main advantages of this approach are two fold. First, this suggested approach is very flexible, especially in the local step and thus the algorithm can be used with any number of processors and with any of the SIMD or MIMD machines. Secondly, the communication complexity is very small and thus can be used as easily with shared memory machines. Several examples for using this strategy are discussed.

Specifying and protecting germ cell fate

PubMed Central

Strome, Susan; Updike, Dustin

2015-01-01

Germ cells are the special cells in the body that undergo meiosis to generate gametes and subsequently entire new organisms after fertilization, a process that continues generation after generation. Recent studies have expanded our understanding of the factors and mechanisms that specify germ cell fate, including the partitioning of maternally supplied ‘germ plasm’, inheritance of epigenetic memory and expression of transcription factors crucial for primordial germ cell (PGC) development. Even after PGCs are specified, germline fate is labile and thus requires protective mechanisms, such as global transcriptional repression, chromatin state alteration and translation of only germline-appropriate transcripts. Findings from diverse species continue to provide insights into the shared and divergent needs of these special reproductive cells. PMID:26122616

Verbal learning in schizopsychotic outpatients and healthy volunteers as a function of cognitive performance levels.

PubMed

Karilampi, Ulla; Helldin, Lars; Hjärthag, Fredrik; Norlander, Torsten; Archer, Trevor

2007-02-01

The aim was to analyze and compare neurocognitive test profiles related to different levels of verbal learning performance among schizopsychotic patients and healthy volunteers. A single-center patient cohort of 196 participants was compared with an equal-sized volunteer group to form three cognitive subgroups based on the shared verbal learning performance. 43.9% of the patients had normal learning ability. Despite this, all patients underperformed the volunteers on all subtests with the exception of working memory, and, for those with high learning ability, even verbal facility. All patients also presented equally poor visuomotor processing speed/efficacy. A global neurocognitive retardation of speed-related processing in schizophrenia is suggested.

Autobiographical memory functions of nostalgia in comparison to rumination and counterfactual thinking: similarity and uniqueness.

PubMed

Cheung, Wing-Yee; Wildschut, Tim; Sedikides, Constantine

2018-02-01

We compared and contrasted nostalgia with rumination and counterfactual thinking in terms of their autobiographical memory functions. Specifically, we assessed individual differences in nostalgia, rumination, and counterfactual thinking, which we then linked to self-reported functions or uses of autobiographical memory (Self-Regard, Boredom Reduction, Death Preparation, Intimacy Maintenance, Conversation, Teach/Inform, and Bitterness Revival). We tested which memory functions are shared and which are uniquely linked to nostalgia. The commonality among nostalgia, rumination, and counterfactual thinking resides in their shared positive associations with all memory functions: individuals who evinced a stronger propensity towards past-oriented thought (as manifested in nostalgia, rumination, and counterfactual thinking) reported greater overall recruitment of memories in the service of present functioning. The uniqueness of nostalgia resides in its comparatively strong positive associations with Intimacy Maintenance, Teach/Inform, and Self-Regard and weak association with Bitterness Revival. In all, nostalgia possesses a more positive functional signature than do rumination and counterfactual thinking.

Mnemonic convergence in social networks: The emergent properties of cognition at a collective level.

PubMed

Coman, Alin; Momennejad, Ida; Drach, Rae D; Geana, Andra

2016-07-19

The development of shared memories, beliefs, and norms is a fundamental characteristic of human communities. These emergent outcomes are thought to occur owing to a dynamic system of information sharing and memory updating, which fundamentally depends on communication. Here we report results on the formation of collective memories in laboratory-created communities. We manipulated conversational network structure in a series of real-time, computer-mediated interactions in fourteen 10-member communities. The results show that mnemonic convergence, measured as the degree of overlap among community members' memories, is influenced by both individual-level information-processing phenomena and by the conversational social network structure created during conversational recall. By studying laboratory-created social networks, we show how large-scale social phenomena (i.e., collective memory) can emerge out of microlevel local dynamics (i.e., mnemonic reinforcement and suppression effects). The social-interactionist approach proposed herein points to optimal strategies for spreading information in social networks and provides a framework for measuring and forging collective memories in communities of individuals.

Using memories to understand others: the role of episodic memory in theory of mind impairment in Alzheimer disease.

PubMed

Moreau, Noémie; Viallet, François; Champagne-Lavau, Maud

2013-09-01

Theory of mind (TOM) refers to the ability to infer one's own and other's mental states. Growing evidence highlighted the presence of impairment on the most complex TOM tasks in Alzheimer disease (AD). However, how TOM deficit is related to other cognitive dysfunctions and more specifically to episodic memory impairment - the prominent feature of this disease - is still under debate. Recent neuroanatomical findings have shown that remembering past events and inferring others' states of mind share the same cerebral network suggesting the two abilities share a common process .This paper proposes to review emergent evidence of TOM impairment in AD patients and to discuss the evidence of a relationship between TOM and episodic memory. We will discuss about AD patients' deficit in TOM being possibly related to their difficulties in recollecting memories of past social interactions. Copyright © 2013 Elsevier B.V. All rights reserved.

Mental time travel and the shaping of the human mind

PubMed Central

Suddendorf, Thomas; Addis, Donna Rose; Corballis, Michael C.

2009-01-01

Episodic memory, enabling conscious recollection of past episodes, can be distinguished from semantic memory, which stores enduring facts about the world. Episodic memory shares a core neural network with the simulation of future episodes, enabling mental time travel into both the past and the future. The notion that there might be something distinctly human about mental time travel has provoked ingenious attempts to demonstrate episodic memory or future simulation in non-human animals, but we argue that they have not yet established a capacity comparable to the human faculty. The evolution of the capacity to simulate possible future events, based on episodic memory, enhanced fitness by enabling action in preparation of different possible scenarios that increased present or future survival and reproduction chances. Human language may have evolved in the first instance for the sharing of past and planned future events, and, indeed, fictional ones, further enhancing fitness in social settings. PMID:19528013

A communication-avoiding, hybrid-parallel, rank-revealing orthogonalization method.

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

Hoemmen, Mark

2010-11-01

Orthogonalization consumes much of the run time of many iterative methods for solving sparse linear systems and eigenvalue problems. Commonly used algorithms, such as variants of Gram-Schmidt or Householder QR, have performance dominated by communication. Here, 'communication' includes both data movement between the CPU and memory, and messages between processors in parallel. Our Tall Skinny QR (TSQR) family of algorithms requires asymptotically fewer messages between processors and data movement between CPU and memory than typical orthogonalization methods, yet achieves the same accuracy as Householder QR factorization. Furthermore, in block orthogonalizations, TSQR is faster and more accurate than existing approaches formore » orthogonalizing the vectors within each block ('normalization'). TSQR's rank-revealing capability also makes it useful for detecting deflation in block iterative methods, for which existing approaches sacrifice performance, accuracy, or both. We have implemented a version of TSQR that exploits both distributed-memory and shared-memory parallelism, and supports real and complex arithmetic. Our implementation is optimized for the case of orthogonalizing a small number (5-20) of very long vectors. The shared-memory parallel component uses Intel's Threading Building Blocks, though its modular design supports other shared-memory programming models as well, including computation on the GPU. Our implementation achieves speedups of 2 times or more over competing orthogonalizations. It is available now in the development branch of the Trilinos software package, and will be included in the 10.8 release.« less

Shared prefetching to reduce execution skew in multi-threaded systems

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

Eichenberger, Alexandre E; Gunnels, John A

Mechanisms are provided for optimizing code to perform prefetching of data into a shared memory of a computing device that is shared by a plurality of threads that execute on the computing device. A memory stream of a portion of code that is shared by the plurality of threads is identified. A set of prefetch instructions is distributed across the plurality of threads. Prefetch instructions are inserted into the instruction sequences of the plurality of threads such that each instruction sequence has a separate sub-portion of the set of prefetch instructions, thereby generating optimized code. Executable code is generated basedmore » on the optimized code and stored in a storage device. The executable code, when executed, performs the prefetches associated with the distributed set of prefetch instructions in a shared manner across the plurality of threads.« less

Working memory, perceptual priming, and the perception of hierarchical forms: opposite effects of priming and working memory without memory refreshing.

PubMed

Kim, Jeong-Im; Humphreys, Glyn W

2010-08-01

Previous research has shown that stimuli held in working memory (WM) can influence spatial attention. Using Navon stimuli, we explored whether and how items in WM affect the perception of visual targets at local and global levels in compound letters. Participants looked for a target letter presented at a local or global level while holding a regular block letter as a memory item. An effect of holding the target's identity in WM was found. When memory items and targets were the same, performance was better than in a neutral condition when the memory item did not appear in the hierarchical letter (a benefit from valid cuing). When the memory item matched the distractor in the hierarchical stimulus, performance was worse than in the neutral baseline (a cost on invalid trials). These effects were greatest when the WM cue matched the global level of the hierarchical stimulus, suggesting that WM biases attention to the global level of form. Interestingly, in a no-memory priming condition, target perception was faster in the invalid condition than in the neutral baseline, reversing the effect in the WM condition. A further control experiment ruled out the effects of WM being due to participants' refreshing their memory from the hierarchical stimulus display. The data show that information in WM biases the selection of hierarchical forms, whereas priming does not. Priming alters the perceptual processing of repeated stimuli without biasing attention.

A shared neural ensemble links distinct contextual memories encoded close in time

NASA Astrophysics Data System (ADS)

Cai, Denise J.; Aharoni, Daniel; Shuman, Tristan; Shobe, Justin; Biane, Jeremy; Song, Weilin; Wei, Brandon; Veshkini, Michael; La-Vu, Mimi; Lou, Jerry; Flores, Sergio E.; Kim, Isaac; Sano, Yoshitake; Zhou, Miou; Baumgaertel, Karsten; Lavi, Ayal; Kamata, Masakazu; Tuszynski, Mark; Mayford, Mark; Golshani, Peyman; Silva, Alcino J.

2016-06-01

Recent studies suggest that a shared neural ensemble may link distinct memories encoded close in time. According to the memory allocation hypothesis, learning triggers a temporary increase in neuronal excitability that biases the representation of a subsequent memory to the neuronal ensemble encoding the first memory, such that recall of one memory increases the likelihood of recalling the other memory. Here we show in mice that the overlap between the hippocampal CA1 ensembles activated by two distinct contexts acquired within a day is higher than when they are separated by a week. Several findings indicate that this overlap of neuronal ensembles links two contextual memories. First, fear paired with one context is transferred to a neutral context when the two contexts are acquired within a day but not across a week. Second, the first memory strengthens the second memory within a day but not across a week. Older mice, known to have lower CA1 excitability, do not show the overlap between ensembles, the transfer of fear between contexts, or the strengthening of the second memory. Finally, in aged mice, increasing cellular excitability and activating a common ensemble of CA1 neurons during two distinct context exposures rescued the deficit in linking memories. Taken together, these findings demonstrate that contextual memories encoded close in time are linked by directing storage into overlapping ensembles. Alteration of these processes by ageing could affect the temporal structure of memories, thus impairing efficient recall of related information.

Factor structure of overall autobiographical memory usage: the directive, self and social functions revisited.

PubMed

Rasmussen, Anne S; Habermas, Tilmann

2011-08-01

According to theory, autobiographical memory serves three broad functions of overall usage: directive, self, and social. However, there is evidence to suggest that the tripartite model may be better conceptualised in terms of a four-factor model with two social functions. In the present study we examined the two models in Danish and German samples, using the Thinking About Life Experiences Questionnaire (TALE; Bluck, Alea, Habermas, & Rubin, 2005), which measures the overall usage of the three functions generalised across concrete memories. Confirmatory factor analysis supported the four-factor model and rejected the theoretical three-factor model in both samples. The results are discussed in relation to cultural differences in overall autobiographical memory usage as well as sharing versus non-sharing aspects of social remembering.

Automated quantitative muscle biopsy analysis system

NASA Technical Reports Server (NTRS)

Castleman, Kenneth R. (Inventor)

1980-01-01

An automated system to aid the diagnosis of neuromuscular diseases by producing fiber size histograms utilizing histochemically stained muscle biopsy tissue. Televised images of the microscopic fibers are processed electronically by a multi-microprocessor computer, which isolates, measures, and classifies the fibers and displays the fiber size distribution. The architecture of the multi-microprocessor computer, which is iterated to any required degree of complexity, features a series of individual microprocessors P.sub.n each receiving data from a shared memory M.sub.n-1 and outputing processed data to a separate shared memory M.sub.n+1 under control of a program stored in dedicated memory M.sub.n.

Parallel performance investigations of an unstructured mesh Navier-Stokes solver

NASA Technical Reports Server (NTRS)

Mavriplis, Dimitri J.

2000-01-01

A Reynolds-averaged Navier-Stokes solver based on unstructured mesh techniques for analysis of high-lift configurations is described. The method makes use of an agglomeration multigrid solver for convergence acceleration. Implicit line-smoothing is employed to relieve the stiffness associated with highly stretched meshes. A GMRES technique is also implemented to speed convergence at the expense of additional memory usage. The solver is cache efficient and fully vectorizable, and is parallelized using a two-level hybrid MPI-OpenMP implementation suitable for shared and/or distributed memory architectures, as well as clusters of shared memory machines. Convergence and scalability results are illustrated for various high-lift cases.

Experimental evaluation of multiprocessor cache-based error recovery

NASA Technical Reports Server (NTRS)

Janssens, Bob; Fuchs, W. K.

1991-01-01

Several variations of cache-based checkpointing for rollback error recovery in shared-memory multiprocessors have been recently developed. By modifying the cache replacement policy, these techniques use the inherent redundancy in the memory hierarchy to periodically checkpoint the computation state. Three schemes, different in the manner in which they avoid rollback propagation, are evaluated. By simulation with address traces from parallel applications running on an Encore Multimax shared-memory multiprocessor, the performance effect of integrating the recovery schemes in the cache coherence protocol are evaluated. The results indicate that the cache-based schemes can provide checkpointing capability with low performance overhead but uncontrollable high variability in the checkpoint interval.

The FORCE - A highly portable parallel programming language

NASA Technical Reports Server (NTRS)

Jordan, Harry F.; Benten, Muhammad S.; Alaghband, Gita; Jakob, Ruediger

1989-01-01

This paper explains why the FORCE parallel programming language is easily portable among six different shared-memory multiprocessors, and how a two-level macro preprocessor makes it possible to hide low-level machine dependencies and to build machine-independent high-level constructs on top of them. These FORCE constructs make it possible to write portable parallel programs largely independent of the number of processes and the specific shared-memory multiprocessor executing them.

The FORCE: A highly portable parallel programming language

NASA Technical Reports Server (NTRS)

Jordan, Harry F.; Benten, Muhammad S.; Alaghband, Gita; Jakob, Ruediger

1989-01-01

Here, it is explained why the FORCE parallel programming language is easily portable among six different shared-memory microprocessors, and how a two-level macro preprocessor makes it possible to hide low level machine dependencies and to build machine-independent high level constructs on top of them. These FORCE constructs make it possible to write portable parallel programs largely independent of the number of processes and the specific shared memory multiprocessor executing them.

Hybrid MPI+OpenMP Programming of an Overset CFD Solver and Performance Investigations

NASA Technical Reports Server (NTRS)

Djomehri, M. Jahed; Jin, Haoqiang H.; Biegel, Bryan (Technical Monitor)

2002-01-01

This report describes a two level parallelization of a Computational Fluid Dynamic (CFD) solver with multi-zone overset structured grids. The approach is based on a hybrid MPI+OpenMP programming model suitable for shared memory and clusters of shared memory machines. The performance investigations of the hybrid application on an SGI Origin2000 (O2K) machine is reported using medium and large scale test problems.

Performing a local reduction operation on a parallel computer

DOEpatents

Blocksome, Michael A; Faraj, Daniel A

2013-06-04

A parallel computer including compute nodes, each including two reduction processing cores, a network write processing core, and a network read processing core, each processing core assigned an input buffer. Copying, in interleaved chunks by the reduction processing cores, contents of the reduction processing cores' input buffers to an interleaved buffer in shared memory; copying, by one of the reduction processing cores, contents of the network write processing core's input buffer to shared memory; copying, by another of the reduction processing cores, contents of the network read processing core's input buffer to shared memory; and locally reducing in parallel by the reduction processing cores: the contents of the reduction processing core's input buffer; every other interleaved chunk of the interleaved buffer; the copied contents of the network write processing core's input buffer; and the copied contents of the network read processing core's input buffer.

Performing a local reduction operation on a parallel computer

DOEpatents

Blocksome, Michael A.; Faraj, Daniel A.

2012-12-11

A parallel computer including compute nodes, each including two reduction processing cores, a network write processing core, and a network read processing core, each processing core assigned an input buffer. Copying, in interleaved chunks by the reduction processing cores, contents of the reduction processing cores' input buffers to an interleaved buffer in shared memory; copying, by one of the reduction processing cores, contents of the network write processing core's input buffer to shared memory; copying, by another of the reduction processing cores, contents of the network read processing core's input buffer to shared memory; and locally reducing in parallel by the reduction processing cores: the contents of the reduction processing core's input buffer; every other interleaved chunk of the interleaved buffer; the copied contents of the network write processing core's input buffer; and the copied contents of the network read processing core's input buffer.

Permanent global amnesia: case report.

PubMed

Bertolucci, Paulo H F; Siviero, Marilena O; Bueno, Orlando F A; Okamoto, Ivan H; Camargo, Candida H P; Santos, Ruth F

2004-04-01

To present a case of permanent global amnesia related to hippocampal damage. Permanent global amnesia is a very rare condition of unknown etiology; lesions restricted to the hippocampus are uncommon, which hinders investigations of this pattern of memory loss. This case is unusually well documented, as the patient underwent extensive neuropsychological evaluations. A cheerful right-handed, 83-year-old retired electrician was first evaluated in 1990 for progressive difficulty in learning new information and in recalling events over the preceding 3-4 years. Tests over the next 5 years showed that the impairment was confined to episodic declarative memory. New verbal information could be stored only in episodic memory in a restricted manner, limited by short-term memory capacity. A relatively mild retrograde amnesia was detected. Semantic and implicit memory was spared, as were other functions evaluated. The patient's language and executive function were strikingly efficient. Magnetic resonance imaging of the brain showed bilateral atrophy of the hippocampi and amygdalae, ruling out conditions such as tumour growth. A diagnosis of permanent global amnesia was made. In the ensuing years, the retrograde amnesia worsened, but no new deficits were identified. This case, the first with a detailed cognitive examination, is evidence of a relatively pure hippocampal pattern for memory loss in permanent global amnesia.

Memory loss

MedlinePlus

... this page: //medlineplus.gov/ency/article/003257.htm Memory loss To use the sharing features on this ... Bethesda, MD 20894 U.S. Department of Health and Human Services National Institutes of Health Page last updated: ...

We Remember, We Forget: Collaborative Remembering in Older Couples

ERIC Educational Resources Information Center

Harris, Celia B.; Keil, Paul G.; Sutton, John; Barnier, Amanda J.; McIlwain, Doris J. F.

2011-01-01

Transactive memory theory describes the processes by which benefits for memory can occur when remembering is shared in dyads or groups. In contrast, cognitive psychology experiments demonstrate that social influences on memory disrupt and inhibit individual recall. However, most research in cognitive psychology has focused on groups of strangers…

76 FR 12821 - 150th Anniversary of the Inauguration of Abraham Lincoln

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-09

... together by shared memories and common hopes. As we observe the 150th anniversary of his Inauguration, we... his memory enabled America to move beyond a young collection of States to become a free and unified... memory and uphold the principles he so nobly advanced. [[Page 12822

Expert Systems on Multiprocessor Architectures. Volume 2. Technical Reports

DTIC Science & Technology

1991-06-01

Report RC 12936 (#58037). IBM T. J. Wartson Reiearch Center. July 1987. � Alan Jay Smith. Cache memories. Coniputing Sitrry., 1.1(3): I.3-5:30...basic-shared is an instrument for ashared memory design. The components panels are processor- qload-scrolling-bar-panel, memory-qload-scrolling-bar-panel

Blanket Gate Would Address Blocks Of Memory

NASA Technical Reports Server (NTRS)

Lambe, John; Moopenn, Alexander; Thakoor, Anilkumar P.

1988-01-01

Circuit-chip area used more efficiently. Proposed gate structure selectively allows and restricts access to blocks of memory in electronic neural-type network. By breaking memory into independent blocks, gate greatly simplifies problem of reading from and writing to memory. Since blocks not used simultaneously, share operational amplifiers that prompt and read information stored in memory cells. Fewer operational amplifiers needed, and chip area occupied reduced correspondingly. Cost per bit drops as result.

The potential of multi-port optical memories in digital computing

NASA Technical Reports Server (NTRS)

Alford, C. O.; Gaylord, T. K.

1975-01-01

A high-capacity memory with a relatively high data transfer rate and multi-port simultaneous access capability may serve as the basis for new computer architectures. The implementation of a multi-port optical memory is discussed. Several computer structures are presented that might profitably use such a memory. These structures include (1) a simultaneous record access system, (2) a simultaneously shared memory computer system, and (3) a parallel digital processing structure.

Methodology for fast detection of false sharing in threaded scientific codes

DOEpatents

Chung, I-Hsin; Cong, Guojing; Murata, Hiroki; Negishi, Yasushi; Wen, Hui-Fang

2014-11-25

A profiling tool identifies a code region with a false sharing potential. A static analysis tool classifies variables and arrays in the identified code region. A mapping detection library correlates memory access instructions in the identified code region with variables and arrays in the identified code region while a processor is running the identified code region. The mapping detection library identifies one or more instructions at risk, in the identified code region, which are subject to an analysis by a false sharing detection library. A false sharing detection library performs a run-time analysis of the one or more instructions at risk while the processor is re-running the identified code region. The false sharing detection library determines, based on the performed run-time analysis, whether two different portions of the cache memory line are accessed by the generated binary code.

Semantic Memory in the Clinical Progression of Alzheimer Disease.

PubMed

Tchakoute, Christophe T; Sainani, Kristin L; Henderson, Victor W

2017-09-01

Semantic memory measures may be useful in tracking and predicting progression of Alzheimer disease. We investigated relationships among semantic memory tasks and their 1-year predictive value in women with Alzheimer disease. We conducted secondary analyses of a randomized clinical trial of raloxifene in 42 women with late-onset mild-to-moderate Alzheimer disease. We assessed semantic memory with tests of oral confrontation naming, category fluency, semantic recognition and semantic naming, and semantic density in written narrative discourse. We measured global cognition (Alzheimer Disease Assessment Scale, cognitive subscale), dementia severity (Clinical Dementia Rating sum of boxes), and daily function (Activities of Daily Living Inventory) at baseline and 1 year. At baseline and 1 year, most semantic memory scores correlated highly or moderately with each other and with global cognition, dementia severity, and daily function. Semantic memory task performance at 1 year had worsened one-third to one-half standard deviation. Factor analysis of baseline test scores distinguished processes in semantic and lexical retrieval (semantic recognition, semantic naming, confrontation naming) from processes in lexical search (semantic density, category fluency). The semantic-lexical retrieval factor predicted global cognition at 1 year. Considered separately, baseline confrontation naming and category fluency predicted dementia severity, while semantic recognition and a composite of semantic recognition and semantic naming predicted global cognition. No individual semantic memory test predicted daily function. Semantic-lexical retrieval and lexical search may represent distinct aspects of semantic memory. Semantic memory processes are sensitive to cognitive decline and dementia severity in Alzheimer disease.

Scalable Triadic Analysis of Large-Scale Graphs: Multi-Core vs. Multi-Processor vs. Multi-Threaded Shared Memory Architectures

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

Chin, George; Marquez, Andres; Choudhury, Sutanay

2012-09-01

Triadic analysis encompasses a useful set of graph mining methods that is centered on the concept of a triad, which is a subgraph of three nodes and the configuration of directed edges across the nodes. Such methods are often applied in the social sciences as well as many other diverse fields. Triadic methods commonly operate on a triad census that counts the number of triads of every possible edge configuration in a graph. Like other graph algorithms, triadic census algorithms do not scale well when graphs reach tens of millions to billions of nodes. To enable the triadic analysis ofmore » large-scale graphs, we developed and optimized a triad census algorithm to efficiently execute on shared memory architectures. We will retrace the development and evolution of a parallel triad census algorithm. Over the course of several versions, we continually adapted the code’s data structures and program logic to expose more opportunities to exploit parallelism on shared memory that would translate into improved computational performance. We will recall the critical steps and modifications that occurred during code development and optimization. Furthermore, we will compare the performances of triad census algorithm versions on three specific systems: Cray XMT, HP Superdome, and AMD multi-core NUMA machine. These three systems have shared memory architectures but with markedly different hardware capabilities to manage parallelism.« less

What Do the Various Principles of Justice Mean Within the Concept of Benefit Sharing?

PubMed

Dauda, Bege; Denier, Yvonne; Dierickx, Kris

2016-06-01

The concept of benefit sharing pertains to the act of giving something in return to the participants, communities, and the country that have participated in global health research or bioprospecting activities. One of the key concerns of benefit sharing is the ethical justifications or reasons to support the practice of the concept in global health research and bioprospecting. This article evaluates one of such ethical justifications and its meaning to benefit sharing, namely justice. We conducted a systematic review to map the various principles of justice that are linked to benefit sharing and analysed their meaning to the concept of benefit sharing. Five principles of justice (commutative, distributive, global, procedural, and compensatory) have been shown to be relevant in the nuances of benefit sharing in both global health research and bioprospecting. The review findings indicate that each of these principles of justice provides a different perspective for a different benefit sharing rationale. For example, commutative justice provides a benefit sharing rationale that is focused on fair exchange of benefits between research sponsors and communities. Distributive justice produces a benefit sharing rationale that is focused on improving the health needs of the vulnerable research communities. We have suggested that a good benefit sharing framework particularly in global health research would be more beneficial if it combines all the principles of justice in its formulation. Nonetheless, there is a need for empirical studies to examine the various principles of justice and their nuances in benefit sharing among stakeholders in global health research.

An Adaptive Insertion and Promotion Policy for Partitioned Shared Caches

NASA Astrophysics Data System (ADS)

Mahrom, Norfadila; Liebelt, Michael; Raof, Rafikha Aliana A.; Daud, Shuhaizar; Hafizah Ghazali, Nur

2018-03-01

Cache replacement policies in chip multiprocessors (CMP) have been investigated extensively and proven able to enhance shared cache management. However, competition among multiple processors executing different threads that require simultaneous access to a shared memory may cause cache contention and memory coherence problems on the chip. These issues also exist due to some drawbacks of the commonly used Least Recently Used (LRU) policy employed in multiprocessor systems, which are because of the cache lines residing in the cache longer than required. In image processing analysis of for example extra pulmonary tuberculosis (TB), an accurate diagnosis for tissue specimen is required. Therefore, a fast and reliable shared memory management system to execute algorithms for processing vast amount of specimen image is needed. In this paper, the effects of the cache replacement policy in a partitioned shared cache are investigated. The goal is to quantify whether better performance can be achieved by using less complex replacement strategies. This paper proposes a Middle Insertion 2 Positions Promotion (MI2PP) policy to eliminate cache misses that could adversely affect the access patterns and the throughput of the processors in the system. The policy employs a static predefined insertion point, near distance promotion, and the concept of ownership in the eviction policy to effectively improve cache thrashing and to avoid resource stealing among the processors.

Not explicit but implicit memory is influenced by individual perception style

PubMed Central

Tsushima, Yoshiaki

2018-01-01

Not only explicit but also implicit memory has considerable influence on our daily life. However, it is still unclear whether explicit and implicit memories are sensitive to individual differences. Here, we investigated how individual perception style (global or local) correlates with implicit and explicit memory. As a result, we found that not explicit but implicit memory was affected by the perception style: local perception style people more greatly used implicit memory than global perception style people. These results help us to make the new effective application adapting to individual perception style and understand some clinical symptoms such as autistic spectrum disorder. Furthermore, this finding might give us new insight of memory involving consciousness and unconsciousness as well as relationship between implicit/explicit memory and individual perception style. PMID:29370212

Not explicit but implicit memory is influenced by individual perception style.

PubMed

Hine, Kyoko; Tsushima, Yoshiaki

2018-01-01

Not only explicit but also implicit memory has considerable influence on our daily life. However, it is still unclear whether explicit and implicit memories are sensitive to individual differences. Here, we investigated how individual perception style (global or local) correlates with implicit and explicit memory. As a result, we found that not explicit but implicit memory was affected by the perception style: local perception style people more greatly used implicit memory than global perception style people. These results help us to make the new effective application adapting to individual perception style and understand some clinical symptoms such as autistic spectrum disorder. Furthermore, this finding might give us new insight of memory involving consciousness and unconsciousness as well as relationship between implicit/explicit memory and individual perception style.

Hierarchical Traces for Reduced NSM Memory Requirements

NASA Astrophysics Data System (ADS)

Dahl, Torbjørn S.

This paper presents work on using hierarchical long term memory to reduce the memory requirements of nearest sequence memory (NSM) learning, a previously published, instance-based reinforcement learning algorithm. A hierarchical memory representation reduces the memory requirements by allowing traces to share common sub-sequences. We present moderated mechanisms for estimating discounted future rewards and for dealing with hidden state using hierarchical memory. We also present an experimental analysis of how the sub-sequence length affects the memory compression achieved and show that the reduced memory requirements do not effect the speed of learning. Finally, we analyse and discuss the persistence of the sub-sequences independent of specific trace instances.

The Contribution of Working Memory to Fluid Reasoning: Capacity, Control, or Both?

ERIC Educational Resources Information Center

Chuderski, Adam; Necka, Edward

2012-01-01

Fluid reasoning shares a large part of its variance with working memory capacity (WMC). The literature on working memory (WM) suggests that the capacity of the focus of attention responsible for simultaneous maintenance and integration of information within WM, as well as the effectiveness of executive control exerted over WM, determines…

Feature-Based Memory-Driven Attentional Capture: Visual Working Memory Content Affects Visual Attention

ERIC Educational Resources Information Center

Olivers, Christian N. L.; Meijer, Frank; Theeuwes, Jan

2006-01-01

In 7 experiments, the authors explored whether visual attention (the ability to select relevant visual information) and visual working memory (the ability to retain relevant visual information) share the same content representations. The presence of singleton distractors interfered more strongly with a visual search task when it was accompanied by…

Time-Related Decay or Interference-Based Forgetting in Working Memory?

ERIC Educational Resources Information Center

Portrat, Sophie; Barrouillet, Pierre; Camos, Valerie

2008-01-01

The time-based resource-sharing model of working memory assumes that memory traces suffer from a time-related decay when attention is occupied by concurrent activities. Using complex continuous span tasks in which temporal parameters are carefully controlled, P. Barrouillet, S. Bernardin, S. Portrat, E. Vergauwe, & V. Camos (2007) recently…

Developmental Change in Working Memory Strategies: From Passive Maintenance to Active Refreshing

ERIC Educational Resources Information Center

Camos, Valerie; Barrouillet, Pierre

2011-01-01

Change in strategies is often mentioned as a source of memory development. However, though performance in working memory tasks steadily improves during childhood, theories differ in linking this development to strategy changes. Whereas some theories, such as the time-based resource-sharing model, invoke the age-related increase in use and…

Cache write generate for parallel image processing on shared memory architectures.

PubMed

Wittenbrink, C M; Somani, A K; Chen, C H

1996-01-01

We investigate cache write generate, our cache mode invention. We demonstrate that for parallel image processing applications, the new mode improves main memory bandwidth, CPU efficiency, cache hits, and cache latency. We use register level simulations validated by the UW-Proteus system. Many memory, cache, and processor configurations are evaluated.

Mnemonic convergence in social networks: The emergent properties of cognition at a collective level

PubMed Central

Coman, Alin; Momennejad, Ida; Drach, Rae D.; Geana, Andra

2016-01-01

The development of shared memories, beliefs, and norms is a fundamental characteristic of human communities. These emergent outcomes are thought to occur owing to a dynamic system of information sharing and memory updating, which fundamentally depends on communication. Here we report results on the formation of collective memories in laboratory-created communities. We manipulated conversational network structure in a series of real-time, computer-mediated interactions in fourteen 10-member communities. The results show that mnemonic convergence, measured as the degree of overlap among community members’ memories, is influenced by both individual-level information-processing phenomena and by the conversational social network structure created during conversational recall. By studying laboratory-created social networks, we show how large-scale social phenomena (i.e., collective memory) can emerge out of microlevel local dynamics (i.e., mnemonic reinforcement and suppression effects). The social-interactionist approach proposed herein points to optimal strategies for spreading information in social networks and provides a framework for measuring and forging collective memories in communities of individuals. PMID:27357678

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

Global health governance as shared health governance.

PubMed

Ruger, Jennifer Prah

2012-07-01

With the exception of key 'proven successes' in global health, the current regime of global health governance can be understood as transnational and national actors pursuing their own interests under a rational actor model of international cooperation, which fails to provide sufficient justification for an obligation to assist in meeting the health needs of others. An ethical commitment to providing all with the ability to be healthy is required. This article develops select components of an alternative model of shared health governance (SHG), which aims to provide a 'road map,' 'focal points' and 'the glue' among various global health actors to better effectuate cooperation on universal ethical principles for an alternative global health equilibrium. Key features of SHG include public moral norms as shared authoritative standards; ethical commitments, shared goals and role allocation; shared sovereignty and constitutional commitments; legitimacy and accountability; country-level attention to international health relations. A framework of social agreement based on 'overlapping consensus' is contrasted against one based on self-interested political bargaining. A global health constitution delineating duties and obligations of global health actors and a global institute of health and medicine for holding actors responsible are proposed. Indicators for empirical assessment of select SHG principles are described. Global health actors, including states, must work together to correct and avert global health injustices through a framework of SHG based on shared ethical commitments.

Importance of balanced architectures in the design of high-performance imaging systems

NASA Astrophysics Data System (ADS)

Sgro, Joseph A.; Stanton, Paul C.

1999-03-01

Imaging systems employed in demanding military and industrial applications, such as automatic target recognition and computer vision, typically require real-time high-performance computing resources. While high- performances computing systems have traditionally relied on proprietary architectures and custom components, recent advances in high performance general-purpose microprocessor technology have produced an abundance of low cost components suitable for use in high-performance computing systems. A common pitfall in the design of high performance imaging system, particularly systems employing scalable multiprocessor architectures, is the failure to balance computational and memory bandwidth. The performance of standard cluster designs, for example, in which several processors share a common memory bus, is typically constrained by memory bandwidth. The symptom characteristic of this problem is failure to the performance of the system to scale as more processors are added. The problem becomes exacerbated if I/O and memory functions share the same bus. The recent introduction of microprocessors with large internal caches and high performance external memory interfaces makes it practical to design high performance imaging system with balanced computational and memory bandwidth. Real word examples of such designs will be presented, along with a discussion of adapting algorithm design to best utilize available memory bandwidth.

An International Framework for Data Sharing: Moving Forward with the Global Alliance for Genomics and Health.

PubMed

Rahimzadeh, Vasiliki; Dyke, Stephanie O M; Knoppers, Bartha M

2016-06-01

The Global Alliance for Genomics and Health is marshaling expertise in biomedical research and data sharing policy to propel bench-to-bedside translation of genomics in parallel with many of the BioSHaRE-EU initiatives described at length in this Issue. Worldwide representation of institutions, funders, researchers, and patient advocacy groups at the Global Alliance is testament to a shared ideal that sees maximizing the public good as a chief priority of genomic innovation in health. The Global Alliance has made a critical stride in this regard with the development of its Framework for Responsible Sharing of Genomic and Health-related Data.(1) This article first discusses the human rights pillars that underlie the Framework and mission of the Global Alliance. Second, it outlines the Global Alliance's use of data governance policies through a number of demonstration projects. Finally, the authors describe how the Global Alliance envisions international data sharing moving forward in the postgenomic era.

Associative-memory representations emerge as shared spatial patterns of theta activity spanning the primate temporal cortex

PubMed Central

Nakahara, Kiyoshi; Adachi, Ken; Kawasaki, Keisuke; Matsuo, Takeshi; Sawahata, Hirohito; Majima, Kei; Takeda, Masaki; Sugiyama, Sayaka; Nakata, Ryota; Iijima, Atsuhiko; Tanigawa, Hisashi; Suzuki, Takafumi; Kamitani, Yukiyasu; Hasegawa, Isao

2016-01-01

Highly localized neuronal spikes in primate temporal cortex can encode associative memory; however, whether memory formation involves area-wide reorganization of ensemble activity, which often accompanies rhythmicity, or just local microcircuit-level plasticity, remains elusive. Using high-density electrocorticography, we capture local-field potentials spanning the monkey temporal lobes, and show that the visual pair-association (PA) memory is encoded in spatial patterns of theta activity in areas TE, 36, and, partially, in the parahippocampal cortex, but not in the entorhinal cortex. The theta patterns elicited by learned paired associates are distinct between pairs, but similar within pairs. This pattern similarity, emerging through novel PA learning, allows a machine-learning decoder trained on theta patterns elicited by a particular visual item to correctly predict the identity of those elicited by its paired associate. Our results suggest that the formation and sharing of widespread cortical theta patterns via learning-induced reorganization are involved in the mechanisms of associative memory representation. PMID:27282247

The costs of changing an intended action: movement planning, but not execution, interferes with verbal working memory.

PubMed

Spiegel, M A; Koester, D; Weigelt, M; Schack, T

2012-02-16

How much cognitive effort does it take to change a movement plan? In previous studies, it has been shown that humans plan and represent actions in advance, but it remains unclear whether or not action planning and verbal working memory share cognitive resources. Using a novel experimental paradigm, we combined in two experiments a grasp-to-place task with a verbal working memory task. Participants planned a placing movement toward one of two target positions and subsequently encoded and maintained visually presented letters. Both experiments revealed that re-planning the intended action reduced letter recall performance; execution time, however, was not influenced by action modifications. The results of Experiment 2 suggest that the action's interference with verbal working memory arose during the planning rather than the execution phase of the movement. Together, our results strongly suggest that movement planning and verbal working memory share common cognitive resources. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Multiple core computer processor with globally-accessible local memories

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

Shalf, John; Donofrio, David; Oliker, Leonid

A multi-core computer processor including a plurality of processor cores interconnected in a Network-on-Chip (NoC) architecture, a plurality of caches, each of the plurality of caches being associated with one and only one of the plurality of processor cores, and a plurality of memories, each of the plurality of memories being associated with a different set of at least one of the plurality of processor cores and each of the plurality of memories being configured to be visible in a global memory address space such that the plurality of memories are visible to two or more of the plurality ofmore » processor cores.« less

Multi-variants synthesis of Petri nets for FPGA devices

NASA Astrophysics Data System (ADS)

Bukowiec, Arkadiusz; Doligalski, Michał

2015-09-01

There is presented new method of synthesis of application specific logic controllers for FPGA devices. The specification of control algorithm is made with use of control interpreted Petri net (PT type). It allows specifying parallel processes in easy way. The Petri net is decomposed into state-machine type subnets. In this case, each subnet represents one parallel process. For this purpose there are applied algorithms of coloring of Petri nets. There are presented two approaches of such decomposition: with doublers of macroplaces or with one global wait place. Next, subnets are implemented into two-level logic circuit of the controller. The levels of logic circuit are obtained as a result of its architectural decomposition. The first level combinational circuit is responsible for generation of next places and second level decoder is responsible for generation output symbols. There are worked out two variants of such circuits: with one shared operational memory or with many flexible distributed memories as a decoder. Variants of Petri net decomposition and structures of logic circuits can be combined together without any restrictions. It leads to existence of four variants of multi-variants synthesis.

Flexible Language Constructs for Large Parallel Programs

DOE PAGES

Rosing, Matt; Schnabel, Robert

1994-01-01

The goal of the research described in this article is to develop flexible language constructs for writing large data parallel numerical programs for distributed memory (multiple instruction multiple data [MIMD]) multiprocessors. Previously, several models have been developed to support synchronization and communication. Models for global synchronization include single instruction multiple data (SIMD), single program multiple data (SPMD), and sequential programs annotated with data distribution statements. The two primary models for communication include implicit communication based on shared memory and explicit communication based on messages. None of these models by themselves seem sufficient to permit the natural and efficient expression ofmore » the variety of algorithms that occur in large scientific computations. In this article, we give an overview of a new language that combines many of these programming models in a clean manner. This is done in a modular fashion such that different models can be combined to support large programs. Within a module, the selection of a model depends on the algorithm and its efficiency requirements. In this article, we give an overview of the language and discuss some of the critical implementation details.« less

Synapsin Determines Memory Strength after Punishment- and Relief-Learning

PubMed Central

Niewalda, Thomas; Michels, Birgit; Jungnickel, Roswitha; Diegelmann, Sören; Kleber, Jörg; Kähne, Thilo

2015-01-01

Adverse life events can induce two kinds of memory with opposite valence, dependent on timing: “negative” memories for stimuli preceding them and “positive” memories for stimuli experienced at the moment of “relief.” Such punishment memory and relief memory are found in insects, rats, and man. For example, fruit flies (Drosophila melanogaster) avoid an odor after odor-shock training (“forward conditioning” of the odor), whereas after shock-odor training (“backward conditioning” of the odor) they approach it. Do these timing-dependent associative processes share molecular determinants? We focus on the role of Synapsin, a conserved presynaptic phosphoprotein regulating the balance between the reserve pool and the readily releasable pool of synaptic vesicles. We find that a lack of Synapsin leaves task-relevant sensory and motor faculties unaffected. In contrast, both punishment memory and relief memory scores are reduced. These defects reflect a true lessening of associative memory strength, as distortions in nonassociative processing (e.g., susceptibility to handling, adaptation, habituation, sensitization), discrimination ability, and changes in the time course of coincidence detection can be ruled out as alternative explanations. Reductions in punishment- and relief-memory strength are also observed upon an RNAi-mediated knock-down of Synapsin, and are rescued both by acutely restoring Synapsin and by locally restoring it in the mushroom bodies of mutant flies. Thus, both punishment memory and relief memory require the Synapsin protein and in this sense share genetic and molecular determinants. We note that corresponding molecular commonalities between punishment memory and relief memory in humans would constrain pharmacological attempts to selectively interfere with excessive associative punishment memories, e.g., after traumatic experiences. PMID:25972175

Synapsin determines memory strength after punishment- and relief-learning.

PubMed

Niewalda, Thomas; Michels, Birgit; Jungnickel, Roswitha; Diegelmann, Sören; Kleber, Jörg; Kähne, Thilo; Gerber, Bertram

2015-05-13

Adverse life events can induce two kinds of memory with opposite valence, dependent on timing: "negative" memories for stimuli preceding them and "positive" memories for stimuli experienced at the moment of "relief." Such punishment memory and relief memory are found in insects, rats, and man. For example, fruit flies (Drosophila melanogaster) avoid an odor after odor-shock training ("forward conditioning" of the odor), whereas after shock-odor training ("backward conditioning" of the odor) they approach it. Do these timing-dependent associative processes share molecular determinants? We focus on the role of Synapsin, a conserved presynaptic phosphoprotein regulating the balance between the reserve pool and the readily releasable pool of synaptic vesicles. We find that a lack of Synapsin leaves task-relevant sensory and motor faculties unaffected. In contrast, both punishment memory and relief memory scores are reduced. These defects reflect a true lessening of associative memory strength, as distortions in nonassociative processing (e.g., susceptibility to handling, adaptation, habituation, sensitization), discrimination ability, and changes in the time course of coincidence detection can be ruled out as alternative explanations. Reductions in punishment- and relief-memory strength are also observed upon an RNAi-mediated knock-down of Synapsin, and are rescued both by acutely restoring Synapsin and by locally restoring it in the mushroom bodies of mutant flies. Thus, both punishment memory and relief memory require the Synapsin protein and in this sense share genetic and molecular determinants. We note that corresponding molecular commonalities between punishment memory and relief memory in humans would constrain pharmacological attempts to selectively interfere with excessive associative punishment memories, e.g., after traumatic experiences. Copyright © 2015 Niewalda et al.

Stability analysis for stochastic BAM nonlinear neural network with delays

NASA Astrophysics Data System (ADS)

Lv, Z. W.; Shu, H. S.; Wei, G. L.

2008-02-01

In this paper, stochastic bidirectional associative memory neural networks with constant or time-varying delays is considered. Based on a Lyapunov-Krasovskii functional and the stochastic stability analysis theory, we derive several sufficient conditions in order to guarantee the global asymptotically stable in the mean square. Our investigation shows that the stochastic bidirectional associative memory neural networks are globally asymptotically stable in the mean square if there are solutions to some linear matrix inequalities(LMIs). Hence, the global asymptotic stability of the stochastic bidirectional associative memory neural networks can be easily checked by the Matlab LMI toolbox. A numerical example is given to demonstrate the usefulness of the proposed global asymptotic stability criteria.

Audience tuning effects in the context of situated and embodied processes.

PubMed

Semin, Gün R

2018-03-05

This review provides an overview of the research on communication and the 'Saying is Believing' paradigm in the context of different perspectives on communication. The process of 'audience tuning' is shaped by a variety of situated factors in contexts that affect the communicators' confidence in their message. The overwhelming common denominator is that the combination of features that create ambiguity yields the optimal condition for the formation of shared realities. I conclude with an argument that the implied invariance of memory processes in shared reality work needs to be more attentive to the regulatory function of memories driving the expression of shared realities. Copyright © 2018 Elsevier Ltd. All rights reserved.

A 300MHz Embedded Flash Memory with Pipeline Architecture and Offset-Free Sense Amplifiers for Dual-Core Automotive Microcontrollers

NASA Astrophysics Data System (ADS)

Kajiyama, Shinya; Fujito, Masamichi; Kasai, Hideo; Mizuno, Makoto; Yamaguchi, Takanori; Shinagawa, Yutaka

A novel 300MHz embedded flash memory for dual-core microcontrollers with a shared ROM architecture is proposed. One of its features is a three-stage pipeline read operation, which enables reduced access pitch and therefore reduces performance penalty due to conflict of shared ROM accesses. Another feature is a highly sensitive sense amplifier that achieves efficient pipeline operation with two-cycle latency one-cycle pitch as a result of a shortened sense time of 0.63ns. The combination of the pipeline architecture and proposed sense amplifiers significantly reduces access-conflict penalties with shared ROM and enhances performance of 32-bit RISC dual-core microcontrollers by 30%.

Emotional state and local versus global spatial memory.

PubMed

Brunyé, Tad T; Mahoney, Caroline R; Augustyn, Jason S; Taylor, Holly A

2009-02-01

The present work investigated the effects of participant emotional state on global versus local memory for map-based information. Participants were placed into one of four emotion induction groups, crossing high and low arousal with positive and negative valence, or a control group. They then studied a university campus map and completed two memory tests, free recall and spatial statement verification. Converging evidence from these two tasks demonstrated that arousal amplifies symbolic distance effects and leads to a globally-focused spatial mental representation, partially at the expense of local knowledge. These results were found for both positively- and negatively-valenced affective states. The present study is the first investigation of emotional effects on spatial memory, and has implications for theories of emotion and spatial cognition.

A general model for memory interference in a multiprocessor system with memory hierarchy

NASA Technical Reports Server (NTRS)

Taha, Badie A.; Standley, Hilda M.

1989-01-01

The problem of memory interference in a multiprocessor system with a hierarchy of shared buses and memories is addressed. The behavior of the processors is represented by a sequence of memory requests with each followed by a determined amount of processing time. A statistical queuing network model for determining the extent of memory interference in multiprocessor systems with clusters of memory hierarchies is presented. The performance of the system is measured by the expected number of busy memory clusters. The results of the analytic model are compared with simulation results, and the correlation between them is found to be very high.

Domain-general involvement of the posterior frontolateral cortex in time-based resource-sharing in working memory: An fMRI study.

PubMed

Vergauwe, Evie; Hartstra, Egbert; Barrouillet, Pierre; Brass, Marcel

2015-07-15

Working memory is often defined in cognitive psychology as a system devoted to the simultaneous processing and maintenance of information. In line with the time-based resource-sharing model of working memory (TBRS; Barrouillet and Camos, 2015; Barrouillet et al., 2004), there is accumulating evidence that, when memory items have to be maintained while performing a concurrent activity, memory performance depends on the cognitive load of this activity, independently of the domain involved. The present study used fMRI to identify regions in the brain that are sensitive to variations in cognitive load in a domain-general way. More precisely, we aimed at identifying brain areas that activate during maintenance of memory items as a direct function of the cognitive load induced by both verbal and spatial concurrent tasks. Results show that the right IFJ and bilateral SPL/IPS are the only areas showing an increased involvement as cognitive load increases and do so in a domain general manner. When correlating the fMRI signal with the approximated cognitive load as defined by the TBRS model, it was shown that the main focus of the cognitive load-related activation is located in the right IFJ. The present findings indicate that the IFJ makes domain-general contributions to time-based resource-sharing in working memory and allowed us to generate the novel hypothesis by which the IFJ might be the neural basis for the process of rapid switching. We argue that the IFJ might be a crucial part of a central attentional bottleneck in the brain because of its inability to upload more than one task rule at once. Copyright © 2015 Elsevier Inc. All rights reserved.

Information and processes underlying semantic and episodic memory across tasks, items, and individuals.

PubMed

Cox, Gregory E; Hemmer, Pernille; Aue, William R; Criss, Amy H

2018-04-01

The development of memory theory has been constrained by a focus on isolated tasks rather than the processes and information that are common to situations in which memory is engaged. We present results from a study in which 453 participants took part in five different memory tasks: single-item recognition, associative recognition, cued recall, free recall, and lexical decision. Using hierarchical Bayesian techniques, we jointly analyzed the correlations between tasks within individuals-reflecting the degree to which tasks rely on shared cognitive processes-and within items-reflecting the degree to which tasks rely on the same information conveyed by the item. Among other things, we find that (a) the processes involved in lexical access and episodic memory are largely separate and rely on different kinds of information, (b) access to lexical memory is driven primarily by perceptual aspects of a word, (c) all episodic memory tasks rely to an extent on a set of shared processes which make use of semantic features to encode both single words and associations between words, and (d) recall involves additional processes likely related to contextual cuing and response production. These results provide a large-scale picture of memory across different tasks which can serve to drive the development of comprehensive theories of memory. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

The impact of social activities, social networks, social support and social relationships on the cognitive functioning of healthy older adults: a systematic review.

PubMed

Kelly, Michelle E; Duff, Hollie; Kelly, Sara; McHugh Power, Joanna E; Brennan, Sabina; Lawlor, Brian A; Loughrey, David G

2017-12-19

Social relationships, which are contingent on access to social networks, promote engagement in social activities and provide access to social support. These social factors have been shown to positively impact health outcomes. In the current systematic review, we offer a comprehensive overview of the impact of social activities, social networks and social support on the cognitive functioning of healthy older adults (50+) and examine the differential effects of aspects of social relationships on various cognitive domains. We followed PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines, and collated data from randomised controlled trials (RCTs), genetic and observational studies. Independent variables of interest included subjective measures of social activities, social networks, and social support, and composite measures of social relationships (CMSR). The primary outcome of interest was cognitive function divided into domains of episodic memory, semantic memory, overall memory ability, working memory, verbal fluency, reasoning, attention, processing speed, visuospatial abilities, overall executive functioning and global cognition. Thirty-nine studies were included in the review; three RCTs, 34 observational studies, and two genetic studies. Evidence suggests a relationship between (1) social activity and global cognition and overall executive functioning, working memory, visuospatial abilities and processing speed but not episodic memory, verbal fluency, reasoning or attention; (2) social networks and global cognition but not episodic memory, attention or processing speed; (3) social support and global cognition and episodic memory but not attention or processing speed; and (4) CMSR and episodic memory and verbal fluency but not global cognition. The results support prior conclusions that there is an association between social relationships and cognitive function but the exact nature of this association remains unclear. Implications of the findings are discussed and suggestions for future research provided. PROSPERO 2012: CRD42012003248 .

What Drives Memory-Driven Attentional Capture? The Effects of Memory Type, Display Type, and Search Type

ERIC Educational Resources Information Center

Olivers, Christian N. L.

2009-01-01

An important question is whether visual attention (the ability to select relevant visual information) and visual working memory (the ability to retain relevant visual information) share the same content representations. Some past research has indicated that they do: Singleton distractors interfered more strongly with a visual search task when they…

Discrete Resource Allocation in Visual Working Memory

ERIC Educational Resources Information Center

Barton, Brian; Ester, Edward F.; Awh, Edward

2009-01-01

Are resources in visual working memory allocated in a continuous or a discrete fashion? On one hand, flexible resource models suggest that capacity is determined by a central resource pool that can be flexibly divided such that items of greater complexity receive a larger share of resources. On the other hand, if capacity in working memory is…

Natural Conversations as a Source of False Memories in Children: Implications for the Testimony of Young Witnesses

PubMed Central

Principe, Gabrielle F.; Schindewolf, Erica

2012-01-01

Research on factors that can affect the accuracy of children’s autobiographical remembering has important implications for understanding the abilities of young witnesses to provide legal testimony. In this article, we review our own recent research on one factor that has much potential to induce errors in children’s event recall, namely natural memory sharing conversations with peers and parents. Our studies provide compelling evidence that not only can the content of conversations about the past intrude into later memory but that such exchanges can prompt the generation of entirely false narratives that are more detailed than true accounts of experienced events. Further, our work show that deeper and more creative participation in memory sharing dialogues can boost the damaging effects of conversationally conveyed misinformation. Implications of this collection of findings for children’s testimony are discussed. PMID:23129880

On nonlinear finite element analysis in single-, multi- and parallel-processors

NASA Technical Reports Server (NTRS)

Utku, S.; Melosh, R.; Islam, M.; Salama, M.

1982-01-01

Numerical solution of nonlinear equilibrium problems of structures by means of Newton-Raphson type iterations is reviewed. Each step of the iteration is shown to correspond to the solution of a linear problem, therefore the feasibility of the finite element method for nonlinear analysis is established. Organization and flow of data for various types of digital computers, such as single-processor/single-level memory, single-processor/two-level-memory, vector-processor/two-level-memory, and parallel-processors, with and without sub-structuring (i.e. partitioning) are given. The effect of the relative costs of computation, memory and data transfer on substructuring is shown. The idea of assigning comparable size substructures to parallel processors is exploited. Under Cholesky type factorization schemes, the efficiency of parallel processing is shown to decrease due to the occasional shared data, just as that due to the shared facilities.

Fencing direct memory access data transfers in a parallel active messaging interface of a parallel computer

DOEpatents

Blocksome, Michael A.; Mamidala, Amith R.

2013-09-03

Fencing direct memory access (`DMA`) data transfers in a parallel active messaging interface (`PAMI`) of a parallel computer, the PAMI including data communications endpoints, each endpoint including specifications of a client, a context, and a task, the endpoints coupled for data communications through the PAMI and through DMA controllers operatively coupled to segments of shared random access memory through which the DMA controllers deliver data communications deterministically, including initiating execution through the PAMI of an ordered sequence of active DMA instructions for DMA data transfers between two endpoints, effecting deterministic DMA data transfers through a DMA controller and a segment of shared memory; and executing through the PAMI, with no FENCE accounting for DMA data transfers, an active FENCE instruction, the FENCE instruction completing execution only after completion of all DMA instructions initiated prior to execution of the FENCE instruction for DMA data transfers between the two endpoints.

Fencing direct memory access data transfers in a parallel active messaging interface of a parallel computer

DOEpatents

Blocksome, Michael A; Mamidala, Amith R

2014-02-11

Fencing direct memory access (`DMA`) data transfers in a parallel active messaging interface (`PAMI`) of a parallel computer, the PAMI including data communications endpoints, each endpoint including specifications of a client, a context, and a task, the endpoints coupled for data communications through the PAMI and through DMA controllers operatively coupled to segments of shared random access memory through which the DMA controllers deliver data communications deterministically, including initiating execution through the PAMI of an ordered sequence of active DMA instructions for DMA data transfers between two endpoints, effecting deterministic DMA data transfers through a DMA controller and a segment of shared memory; and executing through the PAMI, with no FENCE accounting for DMA data transfers, an active FENCE instruction, the FENCE instruction completing execution only after completion of all DMA instructions initiated prior to execution of the FENCE instruction for DMA data transfers between the two endpoints.

Implementation of Parallel Dynamic Simulation on Shared-Memory vs. Distributed-Memory Environments

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

Jin, Shuangshuang; Chen, Yousu; Wu, Di

2015-12-09

Power system dynamic simulation computes the system response to a sequence of large disturbance, such as sudden changes in generation or load, or a network short circuit followed by protective branch switching operation. It consists of a large set of differential and algebraic equations, which is computational intensive and challenging to solve using single-processor based dynamic simulation solution. High-performance computing (HPC) based parallel computing is a very promising technology to speed up the computation and facilitate the simulation process. This paper presents two different parallel implementations of power grid dynamic simulation using Open Multi-processing (OpenMP) on shared-memory platform, and Messagemore » Passing Interface (MPI) on distributed-memory clusters, respectively. The difference of the parallel simulation algorithms and architectures of the two HPC technologies are illustrated, and their performances for running parallel dynamic simulation are compared and demonstrated.« less

Parallelization of NAS Benchmarks for Shared Memory Multiprocessors

NASA Technical Reports Server (NTRS)

Waheed, Abdul; Yan, Jerry C.; Saini, Subhash (Technical Monitor)

1998-01-01

This paper presents our experiences of parallelizing the sequential implementation of NAS benchmarks using compiler directives on SGI Origin2000 distributed shared memory (DSM) system. Porting existing applications to new high performance parallel and distributed computing platforms is a challenging task. Ideally, a user develops a sequential version of the application, leaving the task of porting to new generations of high performance computing systems to parallelization tools and compilers. Due to the simplicity of programming shared-memory multiprocessors, compiler developers have provided various facilities to allow the users to exploit parallelism. Native compilers on SGI Origin2000 support multiprocessing directives to allow users to exploit loop-level parallelism in their programs. Additionally, supporting tools can accomplish this process automatically and present the results of parallelization to the users. We experimented with these compiler directives and supporting tools by parallelizing sequential implementation of NAS benchmarks. Results reported in this paper indicate that with minimal effort, the performance gain is comparable with the hand-parallelized, carefully optimized, message-passing implementations of the same benchmarks.

Shared Leadership for a Green, Global, and Google World

ERIC Educational Resources Information Center

Duin, Ann Hill; Baer, Linda L.

2010-01-01

Higher education institutions must be resilient as they face vastly increased expectations for sustainable environments, global focus, and technological support. Speed of response to these expectations ultimately depends on shared vision, shared agreement, and shared accountability. In this article, the authors challenge all those engaged with…

Going global: the functions of autobiographical memory in cultural context.

PubMed

Alea, Nicole; Wang, Qi

2015-01-01

This special issue of Memory brings together research from around the globe, from Japanese, Chinese and East Indian cultures, to American and European societies, to the Caribbean, to Turkey and to Australia and New Zealand, which examines how and why people, from childhood to old age, remember the personal past in daily life. This journey highlights the important role of the cultural context in shaping the functional usages of autobiographical memory. We illuminate six major contributions of cross-cultural research to a broader and deeper understanding of the functions of autobiographical memory, and call attention to the filed that memory research must "go global."

Biomorphic Multi-Agent Architecture for Persistent Computing

NASA Technical Reports Server (NTRS)

Lodding, Kenneth N.; Brewster, Paul

2009-01-01

A multi-agent software/hardware architecture, inspired by the multicellular nature of living organisms, has been proposed as the basis of design of a robust, reliable, persistent computing system. Just as a multicellular organism can adapt to changing environmental conditions and can survive despite the failure of individual cells, a multi-agent computing system, as envisioned, could adapt to changing hardware, software, and environmental conditions. In particular, the computing system could continue to function (perhaps at a reduced but still reasonable level of performance) if one or more component( s) of the system were to fail. One of the defining characteristics of a multicellular organism is unity of purpose. In biology, the purpose is survival of the organism. The purpose of the proposed multi-agent architecture is to provide a persistent computing environment in harsh conditions in which repair is difficult or impossible. A multi-agent, organism-like computing system would be a single entity built from agents or cells. Each agent or cell would be a discrete hardware processing unit that would include a data processor with local memory, an internal clock, and a suite of communication equipment capable of both local line-of-sight communications and global broadcast communications. Some cells, denoted specialist cells, could contain such additional hardware as sensors and emitters. Each cell would be independent in the sense that there would be no global clock, no global (shared) memory, no pre-assigned cell identifiers, no pre-defined network topology, and no centralized brain or control structure. Like each cell in a living organism, each agent or cell of the computing system would contain a full description of the system encoded as genes, but in this case, the genes would be components of a software genome.

Protection of Mission-Critical Applications from Untrusted Execution Environment: Resource Efficient Replication and Migration of Virtual Machines

DTIC Science & Technology

2015-09-28

the performance of log-and- replay can degrade significantly for VMs configured with multiple virtual CPUs, since the shared memory communication...whether based on checkpoint replication or log-and- replay , existing HA ap- proaches use in- memory backups. The backup VM sits in the memory of a...efficiently. 15. SUBJECT TERMS High-availability virtual machines, live migration, memory and traffic overheads, application suspension, Java

Global positioning system recorder and method

DOEpatents

Hayes, D.W.; Hofstetter, K.J.; Eakle, R.F. Jr.; Reeves, G.E.

1998-12-22

A global positioning system recorder (GPSR) is disclosed in which operational parameters and recorded positional data are stored on a transferable memory element. Through this transferrable memory element, the user of the GPSR need have no knowledge of GPSR devices other than that the memory element needs to be inserted into the memory element slot and the GPSR must be activated. The use of the data element also allows for minimal downtime of the GPSR and the ability to reprogram the GPSR and download data therefrom, without having to physically attach it to another computer. 4 figs.

Global positioning system recorder and method government rights

DOEpatents

Hayes, David W.; Hofstetter, Kenneth J.; Eakle, Jr., Robert F.; Reeves, George E.

1998-01-01

A global positioning system recorder (GPSR) is disclosed in which operational parameters and recorded positional data are stored on a transferable memory element. Through this transferrable memory element, the user of the GPSR need have no knowledge of GPSR devices other than that the memory element needs to be inserted into the memory element slot and the GPSR must be activated. The use of the data element also allows for minimal downtime of the GPSR and the ability to reprogram the GPSR and download data therefrom, without having to physically attach it to another computer.

Parallel processing for scientific computations

NASA Technical Reports Server (NTRS)

Alkhatib, Hasan S.

1995-01-01

The scope of this project dealt with the investigation of the requirements to support distributed computing of scientific computations over a cluster of cooperative workstations. Various experiments on computations for the solution of simultaneous linear equations were performed in the early phase of the project to gain experience in the general nature and requirements of scientific applications. A specification of a distributed integrated computing environment, DICE, based on a distributed shared memory communication paradigm has been developed and evaluated. The distributed shared memory model facilitates porting existing parallel algorithms that have been designed for shared memory multiprocessor systems to the new environment. The potential of this new environment is to provide supercomputing capability through the utilization of the aggregate power of workstations cooperating in a cluster interconnected via a local area network. Workstations, generally, do not have the computing power to tackle complex scientific applications, making them primarily useful for visualization, data reduction, and filtering as far as complex scientific applications are concerned. There is a tremendous amount of computing power that is left unused in a network of workstations. Very often a workstation is simply sitting idle on a desk. A set of tools can be developed to take advantage of this potential computing power to create a platform suitable for large scientific computations. The integration of several workstations into a logical cluster of distributed, cooperative, computing stations presents an alternative to shared memory multiprocessor systems. In this project we designed and evaluated such a system.

Global and Local Processing of Incidental Information and Memory Retrieval at 6 Months.

ERIC Educational Resources Information Center

Bhatt, Ramesh S.; And Others

1994-01-01

Five experiments examined the role of global and local cues in memory retrieval in infancy. Results showed that infants encode and remember for substantial periods of time not only the shape of figures displayed in their periphery but also the global organization of these figures. They also adapt this information when responding to new events.…

ERP Correlates of Encoding Success and Encoding Selectivity in Attention Switching

PubMed Central

Yeung, Nick

2016-01-01

Long-term memory encoding depends critically on effective processing of incoming information. The degree to which participants engage in effective encoding can be indexed in electroencephalographic (EEG) data by studying event-related potential (ERP) subsequent memory effects. The current study investigated ERP correlates of memory success operationalised with two different measures—memory selectivity and global memory—to assess whether previously observed ERP subsequent memory effects reflect focused encoding of task-relevant information (memory selectivity), general encoding success (global memory), or both. Building on previous work, the present study combined an attention switching paradigm—in which participants were presented with compound object-word stimuli and switched between attending to the object or the word across trials—with a later recognition memory test for those stimuli, while recording their EEG. Our results provided clear evidence that subsequent memory effects resulted from selective attentional focusing and effective top-down control (memory selectivity) in contrast to more general encoding success effects (global memory). Further analyses addressed the question of whether successful encoding depended on similar control mechanisms to those involved in attention switching. Interestingly, differences in the ERP correlates of attention switching and successful encoding, particularly during the poststimulus period, indicated that variability in encoding success occurred independently of prestimulus demands for top-down cognitive control. These results suggest that while effects of selective attention and selective encoding co-occur behaviourally their ERP correlates are at least partly dissociable. PMID:27907075

Implementing Shared Memory Parallelism in MCBEND

NASA Astrophysics Data System (ADS)

Bird, Adam; Long, David; Dobson, Geoff

2017-09-01

MCBEND is a general purpose radiation transport Monte Carlo code from AMEC Foster Wheelers's ANSWERS® Software Service. MCBEND is well established in the UK shielding community for radiation shielding and dosimetry assessments. The existing MCBEND parallel capability effectively involves running the same calculation on many processors. This works very well except when the memory requirements of a model restrict the number of instances of a calculation that will fit on a machine. To more effectively utilise parallel hardware OpenMP has been used to implement shared memory parallelism in MCBEND. This paper describes the reasoning behind the choice of OpenMP, notes some of the challenges of multi-threading an established code such as MCBEND and assesses the performance of the parallel method implemented in MCBEND.

Sharing Histories-a transformative learning/teaching method to empower community health workers to support health behavior change of mothers.

PubMed

Altobelli, Laura C

2017-08-23

One of the keys to improving health globally is promoting mothers' adoption of healthy home practices for improved nutrition and illness prevention in the first 1000 days of life from conception. Customarily, mothers are taught health messages which, even if simplified, are hard to remember. The challenge is how to promote learning and behavior change of mothers more effectively in low-resource settings where access to health information is poor, educational levels are low, and traditional beliefs are strong. In addressing that challenge, a new learning/teaching method called "Sharing Histories" is in development to improve the performance of female community health workers (CHWs) in promoting mothers' behaviors for maternal, neonatal and child health (MNCH). This method builds self-confidence and empowerment of CHWs in learning sessions that are built on guided sharing of their own memories of childbearing and child care. CHWs can later share histories with the mother, building her trust and empowerment to change. For professional primary health care staff who are not educators, Sharing Histories is simple to learn and use so that the method can be easily incorporated into government health systems and ongoing CHW programs. I present here the Sharing Histories method, describe how it differs from other social and behavior change methods, and discuss selected literature from psychology, communications, and neuroscience that helps to explain how and why this method works as a transformative tool to engage, teach, transform, and empower CHWs to be more effective change agents with other mothers in their communities, thereby contributing to the attainment of the Sustainable Development Goals.

GPU color space conversion

NASA Astrophysics Data System (ADS)

Chase, Patrick; Vondran, Gary

2011-01-01

Tetrahedral interpolation is commonly used to implement continuous color space conversions from sparse 3D and 4D lookup tables. We investigate the implementation and optimization of tetrahedral interpolation algorithms for GPUs, and compare to the best known CPU implementations as well as to a well known GPU-based trilinear implementation. We show that a 500 NVIDIA GTX-580 GPU is 3x faster than a 1000 Intel Core i7 980X CPU for 3D interpolation, and 9x faster for 4D interpolation. Performance-relevant GPU attributes are explored including thread scheduling, local memory characteristics, global memory hierarchy, and cache behaviors. We consider existing tetrahedral interpolation algorithms and tune based on the structure and branching capabilities of current GPUs. Global memory performance is improved by reordering and expanding the lookup table to ensure optimal access behaviors. Per multiprocessor local memory is exploited to implement optimally coalesced global memory accesses, and local memory addressing is optimized to minimize bank conflicts. We explore the impacts of lookup table density upon computation and memory access costs. Also presented are CPU-based 3D and 4D interpolators, using SSE vector operations that are faster than any previously published solution.

Effects of Aging on True and False Memory Formation: An fMRI Study

ERIC Educational Resources Information Center

Dennis, Nancy A.; Kim, Hongkeun; Cabeza, Roberto

2007-01-01

Compared to young, older adults are more likely to forget events that occurred in the past as well as remember events that never happened. Previous studies examining false memories and aging have shown that these memories are more likely to occur when new items share perceptual or semantic similarities with those presented during encoding. It is…

Ad Hoc Categories and False Memories: Memory Illusions for Categories Created On-The-Spot

ERIC Educational Resources Information Center

Soro, Jerônimo C.; Ferreira, Mário B.; Semin, Gün R.; Mata, André; Carneiro, Paula

2017-01-01

Three experiments were designed to test whether experimentally created ad hoc associative networks evoke false memories. We used the DRM (Deese, Roediger, McDermott) paradigm with lists of ad hoc categories composed of exemplars aggregated toward specific goals (e.g., going for a picnic) that do not share any consistent set of features. Experiment…

Transactive memory in organizational groups: the effects of content, consensus, specialization, and accuracy on group performance.

PubMed

Austin, John R

2003-10-01

Previous research on transactive memory has found a positive relationship between transactive memory system development and group performance in single project laboratory and ad hoc groups. Closely related research on shared mental models and expertise recognition supports these findings. In this study, the author examined the relationship between transactive memory systems and performance in mature, continuing groups. A group's transactive memory system, measured as a combination of knowledge stock, knowledge specialization, transactive memory consensus, and transactive memory accuracy, is positively related to group goal performance, external group evaluations, and internal group evaluations. The positive relationship with group performance was found to hold for both task and external relationship transactive memory systems.

Virtual memory support for distributed computing environments using a shared data object model

NASA Astrophysics Data System (ADS)

Huang, F.; Bacon, J.; Mapp, G.

1995-12-01

Conventional storage management systems provide one interface for accessing memory segments and another for accessing secondary storage objects. This hinders application programming and affects overall system performance due to mandatory data copying and user/kernel boundary crossings, which in the microkernel case may involve context switches. Memory-mapping techniques may be used to provide programmers with a unified view of the storage system. This paper extends such techniques to support a shared data object model for distributed computing environments in which good support for coherence and synchronization is essential. The approach is based on a microkernel, typed memory objects, and integrated coherence control. A microkernel architecture is used to support multiple coherence protocols and the addition of new protocols. Memory objects are typed and applications can choose the most suitable protocols for different types of object to avoid protocol mismatch. Low-level coherence control is integrated with high-level concurrency control so that the number of messages required to maintain memory coherence is reduced and system-wide synchronization is realized without severely impacting the system performance. These features together contribute a novel approach to the support for flexible coherence under application control.

Social Transmission of False Memory in Small Groups and Large Networks.

PubMed

Maswood, Raeya; Rajaram, Suparna

2018-05-21

Sharing information and memories is a key feature of social interactions, making social contexts important for developing and transmitting accurate memories and also false memories. False memory transmission can have wide-ranging effects, including shaping personal memories of individuals as well as collective memories of a network of people. This paper reviews a collection of key findings and explanations in cognitive research on the transmission of false memories in small groups. It also reviews the emerging experimental work on larger networks and collective false memories. Given the reconstructive nature of memory, the abundance of misinformation in everyday life, and the variety of social structures in which people interact, an understanding of transmission of false memories has both scientific and societal implications. © 2018 Cognitive Science Society, Inc.

MULTI: a shared memory approach to cooperative molecular modeling.

PubMed

Darden, T; Johnson, P; Smith, H

1991-03-01

A general purpose molecular modeling system, MULTI, based on the UNIX shared memory and semaphore facilities for interprocess communication is described. In addition to the normal querying or monitoring of geometric data, MULTI also provides processes for manipulating conformations, and for displaying peptide or nucleic acid ribbons, Connolly surfaces, close nonbonded contacts, crystal-symmetry related images, least-squares superpositions, and so forth. This paper outlines the basic techniques used in MULTI to ensure cooperation among these specialized processes, and then describes how they can work together to provide a flexible modeling environment.

SMT-Aware Instantaneous Footprint Optimization

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

Roy, Probir; Liu, Xu; Song, Shuaiwen

Modern architectures employ simultaneous multithreading (SMT) to increase thread-level parallelism. SMT threads share many functional units and the whole memory hierarchy of a physical core. Without a careful code design, SMT threads can easily contend with each other for these shared resources, causing severe performance degradation. Minimizing SMT thread contention for HPC applications running on dedicated platforms is very challenging, because they usually spawn threads within Single Program Multiple Data (SPMD) models. To address this important issue, we introduce a simple scheme for SMT-aware code optimization, which aims to reduce the memory contention across SMT threads.

A Massively Parallel Code for Polarization Calculations

NASA Astrophysics Data System (ADS)

Akiyama, Shizuka; Höflich, Peter

2001-03-01

We present an implementation of our Monte-Carlo radiation transport method for rapidly expanding, NLTE atmospheres for massively parallel computers which utilizes both the distributed and shared memory models. This allows us to take full advantage of the fast communication and low latency inherent to nodes with multiple CPUs, and to stretch the limits of scalability with the number of nodes compared to a version which is based on the shared memory model. Test calculations on a local 20-node Beowulf cluster with dual CPUs showed an improved scalability by about 40%.

Performance Analysis of Multilevel Parallel Applications on Shared Memory Architectures

NASA Technical Reports Server (NTRS)

Jost, Gabriele; Jin, Haoqiang; Labarta, Jesus; Gimenez, Judit; Caubet, Jordi; Biegel, Bryan A. (Technical Monitor)

2002-01-01

In this paper we describe how to apply powerful performance analysis techniques to understand the behavior of multilevel parallel applications. We use the Paraver/OMPItrace performance analysis system for our study. This system consists of two major components: The OMPItrace dynamic instrumentation mechanism, which allows the tracing of processes and threads and the Paraver graphical user interface for inspection and analyses of the generated traces. We describe how to use the system to conduct a detailed comparative study of a benchmark code implemented in five different programming paradigms applicable for shared memory

Cache-based error recovery for shared memory multiprocessor systems

NASA Technical Reports Server (NTRS)

Wu, Kun-Lung; Fuchs, W. Kent; Patel, Janak H.

1989-01-01

A multiprocessor cache-based checkpointing and recovery scheme for of recovering from transient processor errors in a shared-memory multiprocessor with private caches is presented. New implementation techniques that use checkpoint identifiers and recovery stacks to reduce performance degradation in processor utilization during normal execution are examined. This cache-based checkpointing technique prevents rollback propagation, provides for rapid recovery, and can be integrated into standard cache coherence protocols. An analytical model is used to estimate the relative performance of the scheme during normal execution. Extensions that take error latency into account are presented.

Designing for Global Data Sharing, Designing for Educational Transformation

ERIC Educational Resources Information Center

Adams, Robin S.; Radcliffe, David; Fosmire, Michael

2016-01-01

This paper provides an example of a global data sharing project with an educational transformation agenda. This agenda shaped both the design of the shared dataset and the experience of sharing the common dataset to support multiple perspective inquiry and enable integrative and critically reflexive research-to-practice dialogue. The shared…

Memory behaviors of entropy production rates in heat conduction

NASA Astrophysics Data System (ADS)

Li, Shu-Nan; Cao, Bing-Yang

2018-02-01

Based on the relaxation time approximation and first-order expansion, memory behaviors in heat conduction are found between the macroscopic and Boltzmann-Gibbs-Shannon (BGS) entropy production rates with exponentially decaying memory kernels. In the frameworks of classical irreversible thermodynamics (CIT) and BGS statistical mechanics, the memory dependency on the integrated history is unidirectional, while for the extended irreversible thermodynamics (EIT) and BGS entropy production rates, the memory dependences are bidirectional and coexist with the linear terms. When macroscopic and microscopic relaxation times satisfy a specific relationship, the entropic memory dependences will be eliminated. There also exist initial effects in entropic memory behaviors, which decay exponentially. The second-order term are also discussed, which can be understood as the global non-equilibrium degree. The effects of the second-order term are consisted of three parts: memory dependency, initial value and linear term. The corresponding memory kernels are still exponential and the initial effects of the global non-equilibrium degree also decay exponentially.

Mechanisms of Age-Related Decline in Memory Search Across the Adult Life Span

PubMed Central

Hills, Thomas T.; Mata, Rui; Wilke, Andreas; Samanez-Larkin, Gregory R.

2013-01-01

Three alternative mechanisms for age-related decline in memory search have been proposed, which result from either reduced processing speed (global slowing hypothesis), overpersistence on categories (cluster-switching hypothesis), or the inability to maintain focus on local cues related to a decline in working memory (cue-maintenance hypothesis). We investigated these 3 hypotheses by formally modeling the semantic recall patterns of 185 adults between 27 to 99 years of age in the animal fluency task (Thurstone, 1938). The results indicate that people switch between global frequency-based retrieval cues and local item-based retrieval cues to navigate their semantic memory. Contrary to the global slowing hypothesis that predicts no qualitative differences in dynamic search processes and the cluster-switching hypothesis that predicts reduced switching between retrieval cues, the results indicate that as people age, they tend to switch more often between local and global cues per item recalled, supporting the cue-maintenance hypothesis. Additional support for the cue-maintenance hypothesis is provided by a negative correlation between switching and digit span scores and between switching and total items recalled, which suggests that cognitive control may be involved in cue maintenance and the effective search of memory. Overall, the results are consistent with age-related decline in memory search being a consequence of reduced cognitive control, consistent with models suggesting that working memory is related to goal perseveration and the ability to inhibit distracting information. PMID:23586941

Avoiding and tolerating latency in large-scale next-generation shared-memory multiprocessors

NASA Technical Reports Server (NTRS)

Probst, David K.

1993-01-01

A scalable solution to the memory-latency problem is necessary to prevent the large latencies of synchronization and memory operations inherent in large-scale shared-memory multiprocessors from reducing high performance. We distinguish latency avoidance and latency tolerance. Latency is avoided when data is brought to nearby locales for future reference. Latency is tolerated when references are overlapped with other computation. Latency-avoiding locales include: processor registers, data caches used temporally, and nearby memory modules. Tolerating communication latency requires parallelism, allowing the overlap of communication and computation. Latency-tolerating techniques include: vector pipelining, data caches used spatially, prefetching in various forms, and multithreading in various forms. Relaxing the consistency model permits increased use of avoidance and tolerance techniques. Each model is a mapping from the program text to sets of partial orders on program operations; it is a convention about which temporal precedences among program operations are necessary. Information about temporal locality and parallelism constrains the use of avoidance and tolerance techniques. Suitable architectural primitives and compiler technology are required to exploit the increased freedom to reorder and overlap operations in relaxed models.

Recovery of an injured cingulum concurrent with improvement of short-term memory in a patient with mild traumatic brain injury.

PubMed

Jang, Sung Ho; Kim, Seong Ho; Seo, Jeong Pyo

2018-01-01

We reported on a patient with mild traumatic brain injury (TBI) who showed recovery of an injured cingulum concurrent with improvement of short-term memory, which was demonstrated on follow-up diffusion tensor tractography (DTT). A 55-year-old male patient suffered head trauma resulting from falling from approximately 2 m while working at a construction site. The patient showed mild memory impairment (especially short-term memory impairment) at 3 months after onset: Memory Assessment Scale (global memory: 95 (37%ile), short-term memory: 75 (5%ile), verbal memory: 80 (9%ile) and visual memory: 112 (79%ile)). By contrast, at 2 years after onset, his mild memory impairment had improved to a normal state: Memory Assessment Scale (global memory: 104 (61%ile), short-term memory: 95 (37%ile), verbal memory: 101 (53%ile) and visual memory: 106 (66%ile)). On 3-month DTT, discontinuation of the right anterior cingulum was observed over the genu of the corpus callosum, while on 2-year DTT, the discontinued right anterior cingulum was elongated to the right basal forebrain. In conclusion, recovery of an injured cingulum concurrent with improvement of short-term memory was demonstrated in a patient with mild TBI.

Semantic memory and frontal executive function during transient global amnesia.

PubMed

Hodges, J R

1994-05-01

To assess semantic memory and frontal executive function, two patients underwent neuropsychological testing during transient global amnesia (TGA) and after an interval of 6-8 weeks. In spite of a profound deficit in anterograde verbal and non-verbal memory, semantic memory was normal, as judged by category fluency measures, picture naming, and picture-word and picture-picture matching, and reading ability was normal. Similarly, there were no deficits on a number of tests known to be sensitive to frontal executive dysfunction. A hexamethylpropyleneamine-oxime (HMPAO) single photon emission CT (SPECT) scan, obtained on one patient 24 hours post-TGA, showed focal left temporal lobe hypoperfusion which had resolved three months later. The observed dissociation between episodic and semantic memory is discussed in the light of contemporary cognitive theories of memory organisation.

Power/Performance Trade-offs of Small Batched LU Based Solvers on GPUs

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

Villa, Oreste; Fatica, Massimiliano; Gawande, Nitin A.

In this paper we propose and analyze a set of batched linear solvers for small matrices on Graphic Processing Units (GPUs), evaluating the various alternatives depending on the size of the systems to solve. We discuss three different solutions that operate with different level of parallelization and GPU features. The first, exploiting the CUBLAS library, manages matrices of size up to 32x32 and employs Warp level (one matrix, one Warp) parallelism and shared memory. The second works at Thread-block level parallelism (one matrix, one Thread-block), still exploiting shared memory but managing matrices up to 76x76. The third is Thread levelmore » parallel (one matrix, one thread) and can reach sizes up to 128x128, but it does not exploit shared memory and only relies on the high memory bandwidth of the GPU. The first and second solution only support partial pivoting, the third one easily supports partial and full pivoting, making it attractive to problems that require greater numerical stability. We analyze the trade-offs in terms of performance and power consumption as function of the size of the linear systems that are simultaneously solved. We execute the three implementations on a Tesla M2090 (Fermi) and on a Tesla K20 (Kepler).« less

A neuropsychological comparison of obsessive-compulsive disorder and trichotillomania.

PubMed

Chamberlain, Samuel R; Fineberg, Naomi A; Blackwell, Andrew D; Clark, Luke; Robbins, Trevor W; Sahakian, Barbara J

2007-03-02

Obsessive-compulsive disorder (OCD) and trichotillomania (compulsive hair-pulling) share overlapping co-morbidity, familial transmission, and phenomenology. However, the extent to which these disorders share a common cognitive phenotype has yet to be elucidated using patients without confounding co-morbidities. To compare neurocognitive functioning in co-morbidity-free patients with OCD and trichotillomania, focusing on domains of learning and memory, executive function, affective processing, reflection-impulsivity and decision-making. Twenty patients with OCD, 20 patients with trichotillomania, and 20 matched controls undertook neuropsychological assessment after meeting stringent inclusion criteria. Groups were matched for age, education, verbal IQ, and gender. The OCD and trichotillomania groups were impaired on spatial working memory. Only OCD patients showed additional impairments on executive planning and visual pattern recognition memory, and missed more responses to sad target words than other groups on an affective go/no-go task. Furthermore, OCD patients failed to modulate their behaviour between conditions on the reflection-impulsivity test, suggestive of cognitive inflexibility. Both clinical groups showed intact decision-making and probabilistic reversal learning. OCD and trichotillomania shared overlapping spatial working memory problems, but neuropsychological dysfunction in OCD spanned additional domains that were intact in trichotillomania. Findings are discussed in relation to likely fronto-striatal neural substrates and future research directions.

Long-term memory following transient global amnesia: an investigation of episodic and semantic memory.

PubMed

Guillery-Girard, B; Quinette, P; Desgranges, B; Piolino, P; Viader, F; de la Sayette, V; Eustache, F

2006-11-01

Several studies noted persistence of memory impairment following an episode of transient global amnesia (TGA) with standard tests. To specify long-term memory impairments in a group of patients selected with stringent criteria. Both retrograde and anterograde memory were investigated in 32 patients 13-67 months after a TGA episode with original tasks encompassing retrograde semantic memory (academic, public and personal knowledge), retrograde episodic memory (autobiographical events) and anterograde episodic memory. Patients had preserved academic and public knowledge. Pathological scores were obtained in personal verbal fluency for the two most recent periods, and patients produced less autobiographical events than controls. However, when they were provided time to detail, memories were as episodic as in controls regardless of their remoteness. Anterograde episodic tasks revealed a mild but significant impairment of the capacity of re-living the condition of encoding, i.e. the moment at which words were presented. Patients who have suffered from an episode of TGA manifest deficits of memory focused on the retrieval of both recent semantic information and episodic memories and especially the capacity of re-living. These deficits may not result from a deterioration of memory per se but rather from difficulties in accessing memories.

Benefit Sharing in a Global Context: Working Towards Solutions for Implementation.

PubMed

Hurst, Daniel J

2017-08-01

Due to the state of globalized clinical research, questions have been raised as to what, if any, benefits those who contribute to research should receive. One model for compensating research participants is "benefit sharing," and the basic premise is that, as a matter of justice, those who contribute to scientific research should share in its benefits. While incorporated into several international documents for over two decades, benefit sharing has only been sparsely implemented. This analysis begins by addressing the concept of benefit sharing, its historical development, and how it has been applied in the context of virus sharing for influenza research. The second portion of this analysis presents recommendations for ensuring benefit sharing. These recommendations are threefold: 1) an emphasis on social pressure, 2) the revision of international documents as means to ensure benefit sharing, and 3) greater collaboration between sponsor IRB and host country IRB. Because clinical research is a globalized industry, a global model will be proposed in the second that focuses on collaboration between the sponsor and host country. This collaboration is vital in order to ensure that proper forms of benefit sharing are accomplished as a matter of justice. © 2016 John Wiley & Sons Ltd.

Transient global amnesia: implicit/explicit memory dissociation and PET assessment of brain perfusion and oxygen metabolism in the acute stage.

PubMed

Eustache, F; Desgranges, B; Petit-Taboué, M C; de la Sayette, V; Piot, V; Sablé, C; Marchal, G; Baron, J C

1997-09-01

To assess explicit memory and two components of implicit memory--that is, perceptual-verbal skill learning and lexical-semantic priming effects--as well as resting cerebral blood flow (CBF) and oxygen metabolism (CMRO2) during the acute phase of transient global amnesia. In a 59 year old woman, whose amnestic episode fulfilled all current criteria for transient global amnesia, a neuropsychological protocol was administered, including word learning, story recall, categorical fluency, mirror reading, and word stem completion tasks. PET was performed using the (15)O steady state inhalation method, while the patient still exhibited severe anterograde amnesia and was interleaved with the cognitive tests. There was a clear cut dissociation between impaired long term episodic memory and preserved implicit memory for its two components. Categorical fluency was significantly altered, suggesting word retrieval strategy--rather than semantic memory--impairment. The PET study disclosed a reduced CMRO2 with relatively or fully preserved CBF in the left prefrontotemporal cortex and lentiform nucleus, and the reverse pattern over the left occipital cortex. The PET alterations with patchy CBF-CMRO2 uncoupling would be compatible with a migraine-like phenomenon and indicate that the isolated assessment of perfusion in transient global amnesia may be misleading. The pattern of metabolic depression, with sparing of the hippocampal area, is one among the distinct patterns of brain dysfunction that underlie the (apparently) uniform clinical presentation of transient global amnesia. The finding of a left prefrontal hypometabolism in the face of impaired episodic memory and altered verbal fluency would fit present day concepts from PET activation studies about the role of this area in episodic and semantic memory encoding/retrieval. Likewise, the changes affecting the lenticular nucleus but sparing the caudate would be consistent with the normal performance in perceptual-verbal skill learning. Finally, unaltered lexical-semantic priming effects, despite left temporal cortex hypometabolism, suggest that these processes are subserved by a more distributed neocortical network.

Parallel Clustering Algorithm for Large-Scale Biological Data Sets

PubMed Central

Wang, Minchao; Zhang, Wu; Ding, Wang; Dai, Dongbo; Zhang, Huiran; Xie, Hao; Chen, Luonan; Guo, Yike; Xie, Jiang

2014-01-01

Backgrounds Recent explosion of biological data brings a great challenge for the traditional clustering algorithms. With increasing scale of data sets, much larger memory and longer runtime are required for the cluster identification problems. The affinity propagation algorithm outperforms many other classical clustering algorithms and is widely applied into the biological researches. However, the time and space complexity become a great bottleneck when handling the large-scale data sets. Moreover, the similarity matrix, whose constructing procedure takes long runtime, is required before running the affinity propagation algorithm, since the algorithm clusters data sets based on the similarities between data pairs. Methods Two types of parallel architectures are proposed in this paper to accelerate the similarity matrix constructing procedure and the affinity propagation algorithm. The memory-shared architecture is used to construct the similarity matrix, and the distributed system is taken for the affinity propagation algorithm, because of its large memory size and great computing capacity. An appropriate way of data partition and reduction is designed in our method, in order to minimize the global communication cost among processes. Result A speedup of 100 is gained with 128 cores. The runtime is reduced from serval hours to a few seconds, which indicates that parallel algorithm is capable of handling large-scale data sets effectively. The parallel affinity propagation also achieves a good performance when clustering large-scale gene data (microarray) and detecting families in large protein superfamilies. PMID:24705246

77 FR 36599 - Self-Regulatory Organizations; NYSE Arca, Inc.; Notice of Filing and Immediate Effectiveness of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-19

... Change Relating to the Accuvest Global Long Short ETF (Formerly the Mars Hill Global Relative Value ETF...) applicable to, the Accuvest Global Long Short ETF (``Fund'') (formerly known as the Mars Hill Global Relative... the Exchange of shares (``Shares'') of the Mars Hill Global Relative Value ETF, a series of Advisor...

Remembering everyday experience through the prism of self-esteem.

PubMed

Christensen, Tamlin Conner; Wood, Joanne V; Barrett, Lisa Feldman

2003-01-01

Two studies examined whether global self-esteem was associated with bias in memory for autobiographical experience. For 7 days, participants described specific events and made ratings of their experience (i.e., state self-esteem, positive and negative emotion, and perceived valence of the event) in response to each event. Later, participants were presented with their event descriptions and were asked to recall their experience ratings from memory. As hypothesized, higher global self-esteem predicted positive shifts in memory for experience, whereas lower global self-esteem predicted negative shifts in memory for experience. Patterns of bias were strongest for remembered state self-esteem, moderate for positive emotion, and minimal for event valence. Self-esteem did not predict bias for negative emotion. Mood at the time of recall (measured in Study 2) generally did not account for the patterns. These findings strengthen the view that self-esteem is a rich source of knowledge about the self that can influence memory for some kinds of autobiographical experience. Copyright 2003 Society for Personality and Social Psychology, Inc.

Memory underpinnings of future intentions: Would you like to see the sequel?

PubMed

Stragà, Marta; Del Missier, Fabio; Marcatto, Francesco; Ferrante, Donatella

2017-01-01

In two studies, we investigated the memory underpinnings of future intentions related to past hedonic experiences. Preceding research did not make clear whether the specific memory processes supporting the expression of intentions about the future involve global judgments of the past experience (general affective evaluations formed on-line) or judgments derived from the episodic recollection of the past. Adapting a correlational paradigm previously employed to study future intentions, and applying it to the experience of watching a movie, we comparatively tested the influence of global retrospective evaluations vs. episodic-derived evaluations on future intentions. In Study 1, in which the intentions involved a future experience that was very similar to an overall past one (e.g., seeing the movie sequel), the findings showed that participants relied only on global judgments to form future intentions. In Study 2, in which the global judgment on the past was less diagnostic because the future intentions referred to specific parts of the past experience (e.g., watching a movie centered on a minor character in the previously seen movie), the results indicated that relevant episodic memories provided an essential contribution to the prediction of future intentions. These findings are in agreement with the predictions of the accessibility-diagnosticity framework and they show that global judgments and episodic memories of a past experience contribute differentially to diverse kinds of future intentions.

Memory underpinnings of future intentions: Would you like to see the sequel?

PubMed Central

Marcatto, Francesco; Ferrante, Donatella

2017-01-01

In two studies, we investigated the memory underpinnings of future intentions related to past hedonic experiences. Preceding research did not make clear whether the specific memory processes supporting the expression of intentions about the future involve global judgments of the past experience (general affective evaluations formed on-line) or judgments derived from the episodic recollection of the past. Adapting a correlational paradigm previously employed to study future intentions, and applying it to the experience of watching a movie, we comparatively tested the influence of global retrospective evaluations vs. episodic-derived evaluations on future intentions. In Study 1, in which the intentions involved a future experience that was very similar to an overall past one (e.g., seeing the movie sequel), the findings showed that participants relied only on global judgments to form future intentions. In Study 2, in which the global judgment on the past was less diagnostic because the future intentions referred to specific parts of the past experience (e.g., watching a movie centered on a minor character in the previously seen movie), the results indicated that relevant episodic memories provided an essential contribution to the prediction of future intentions. These findings are in agreement with the predictions of the accessibility-diagnosticity framework and they show that global judgments and episodic memories of a past experience contribute differentially to diverse kinds of future intentions. PMID:28448567

A parallel approximate string matching under Levenshtein distance on graphics processing units using warp-shuffle operations

PubMed Central

Ho, ThienLuan; Oh, Seung-Rohk

2017-01-01

Approximate string matching with k-differences has a number of practical applications, ranging from pattern recognition to computational biology. This paper proposes an efficient memory-access algorithm for parallel approximate string matching with k-differences on Graphics Processing Units (GPUs). In the proposed algorithm, all threads in the same GPUs warp share data using warp-shuffle operation instead of accessing the shared memory. Moreover, we implement the proposed algorithm by exploiting the memory structure of GPUs to optimize its performance. Experiment results for real DNA packages revealed that the performance of the proposed algorithm and its implementation archived up to 122.64 and 1.53 times compared to that of sequential algorithm on CPU and previous parallel approximate string matching algorithm on GPUs, respectively. PMID:29016700

Alzheimer's disease can spare local metacognition despite global anosognosia: revisiting the confidence-accuracy relationship in episodic memory.

PubMed

Gallo, David A; Cramer, Stefanie J; Wong, Jessica T; Bennett, David A

2012-07-01

Alzheimer's disease (AD) can impair metacognition in addition to more basic cognitive functions like memory. However, while global metacognitive inaccuracies are well documented (i.e., low deficit awareness, or anosognosia), the evidence is mixed regarding the effects of AD on local or task-based metacognitive judgments. Here we investigated local metacognition with respect to the confidence-accuracy relationship in episodic memory (i.e., metamemory). AD and control participants studied pictures of common objects and their verbal labels, and then took forced-choice picture recollection tests using the verbal labels as retrieval cues. We found that item-based confidence judgments discriminated between accurate and inaccurate recollection responses in both groups, implicating relatively spared metamemory in AD. By contrast, there was evidence for global metacognitive deficiencies, as AD participants underestimated the severity of their everyday problems compared to an informant's assessment. Within the AD group, individual differences in global metacognition were related to recollection accuracy, and global metacognition for everyday memory problems was related to task-based metacognitive accuracy. These findings suggest that AD can spare the confidence-accuracy relationship in recollection tasks, and that global and local metacognition measures tap overlapping neuropsychological processes. Copyright © 2012 Elsevier Ltd. All rights reserved.

Relative time sharing: new findings and an extension of the resource allocation model of temporal processing.

PubMed

Buhusi, Catalin V; Meck, Warren H

2009-07-12

Individuals time as if using a stopwatch that can be stopped or reset on command. Here, we review behavioural and neurobiological data supporting the time-sharing hypothesis that perceived time depends on the attentional and memory resources allocated to the timing process. Neuroimaging studies in humans suggest that timekeeping tasks engage brain circuits typically involved in attention and working memory. Behavioural, pharmacological, lesion and electrophysiological studies in lower animals support this time-sharing hypothesis. When subjects attend to a second task, or when intruder events are presented, estimated durations are shorter, presumably due to resources being taken away from timing. Here, we extend the time-sharing hypothesis by proposing that resource reallocation is proportional to the perceived contrast, both in temporal and non-temporal features, between intruders and the timed events. New findings support this extension by showing that the effect of an intruder event is dependent on the relative duration of the intruder to the intertrial interval. The conclusion is that the brain circuits engaged by timekeeping comprise not only those primarily involved in time accumulation, but also those involved in the maintenance of attentional and memory resources for timing, and in the monitoring and reallocation of those resources among tasks.

Implementing High-Performance Geometric Multigrid Solver with Naturally Grained Messages

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

Shan, Hongzhang; Williams, Samuel; Zheng, Yili

2015-10-26

Structured-grid linear solvers often require manually packing and unpacking of communication data to achieve high performance.Orchestrating this process efficiently is challenging, labor-intensive, and potentially error-prone.In this paper, we explore an alternative approach that communicates the data with naturally grained messagesizes without manual packing and unpacking. This approach is the distributed analogue of shared-memory programming, taking advantage of the global addressspace in PGAS languages to provide substantial programming ease. However, its performance may suffer from the large number of small messages. We investigate theruntime support required in the UPC ++ library for this naturally grained version to close the performance gapmore » between the two approaches and attain comparable performance at scale using the High-Performance Geometric Multgrid (HPGMG-FV) benchmark as a driver.« less

Is functional integration of resting state brain networks an unspecific biomarker for working memory performance?

PubMed

Alavash, Mohsen; Doebler, Philipp; Holling, Heinz; Thiel, Christiane M; Gießing, Carsten

2015-03-01

Is there one optimal topology of functional brain networks at rest from which our cognitive performance would profit? Previous studies suggest that functional integration of resting state brain networks is an important biomarker for cognitive performance. However, it is still unknown whether higher network integration is an unspecific predictor for good cognitive performance or, alternatively, whether specific network organization during rest predicts only specific cognitive abilities. Here, we investigated the relationship between network integration at rest and cognitive performance using two tasks that measured different aspects of working memory; one task assessed visual-spatial and the other numerical working memory. Network clustering, modularity and efficiency were computed to capture network integration on different levels of network organization, and to statistically compare their correlations with the performance in each working memory test. The results revealed that each working memory aspect profits from a different resting state topology, and the tests showed significantly different correlations with each of the measures of network integration. While higher global network integration and modularity predicted significantly better performance in visual-spatial working memory, both measures showed no significant correlation with numerical working memory performance. In contrast, numerical working memory was superior in subjects with highly clustered brain networks, predominantly in the intraparietal sulcus, a core brain region of the working memory network. Our findings suggest that a specific balance between local and global functional integration of resting state brain networks facilitates special aspects of cognitive performance. In the context of working memory, while visual-spatial performance is facilitated by globally integrated functional resting state brain networks, numerical working memory profits from increased capacities for local processing, especially in brain regions involved in working memory performance. Copyright © 2014 Elsevier Inc. All rights reserved.

Swarming UAS II

DTIC Science & Technology

2010-05-05

employed biomimicry to model a swarm of UAS as a colony of ants, where each UAS dynamically updates a global memory map, allowing pheromone-like...matter of design, DSE-R-0808 employed biomimicry to model a swarm of UAS as a colony of ants, where each UAS dynamically updates a global memory map

An experimental distributed microprocessor implementation with a shared memory communications and control medium

NASA Technical Reports Server (NTRS)

Mejzak, R. S.

1980-01-01

The distributed processing concept is defined in terms of control primitives, variables, and structures and their use in performing a decomposed discrete Fourier transform (DET) application function. The design assumes interprocessor communications to be anonymous. In this scheme, all processors can access an entire common database by employing control primitives. Access to selected areas within the common database is random, enforced by a hardware lock, and determined by task and subtask pointers. This enables the number of processors to be varied in the configuration without any modifications to the control structure. Decompositional elements of the DFT application function in terms of tasks and subtasks are also described. The experimental hardware configuration consists of IMSAI 8080 chassis which are independent, 8 bit microcomputer units. These chassis are linked together to form a multiple processing system by means of a shared memory facility. This facility consists of hardware which provides a bus structure to enable up to six microcomputers to be interconnected. It provides polling and arbitration logic so that only one processor has access to shared memory at any one time.

Running ATLAS workloads within massively parallel distributed applications using Athena Multi-Process framework (AthenaMP)

NASA Astrophysics Data System (ADS)

Calafiura, Paolo; Leggett, Charles; Seuster, Rolf; Tsulaia, Vakhtang; Van Gemmeren, Peter

2015-12-01

AthenaMP is a multi-process version of the ATLAS reconstruction, simulation and data analysis framework Athena. By leveraging Linux fork and copy-on-write mechanisms, it allows for sharing of memory pages between event processors running on the same compute node with little to no change in the application code. Originally targeted to optimize the memory footprint of reconstruction jobs, AthenaMP has demonstrated that it can reduce the memory usage of certain configurations of ATLAS production jobs by a factor of 2. AthenaMP has also evolved to become the parallel event-processing core of the recently developed ATLAS infrastructure for fine-grained event processing (Event Service) which allows the running of AthenaMP inside massively parallel distributed applications on hundreds of compute nodes simultaneously. We present the architecture of AthenaMP, various strategies implemented by AthenaMP for scheduling workload to worker processes (for example: Shared Event Queue and Shared Distributor of Event Tokens) and the usage of AthenaMP in the diversity of ATLAS event processing workloads on various computing resources: Grid, opportunistic resources and HPC.

Neonatal Brain Abnormalities and Memory and Learning Outcomes at 7 Years in Children Born Very Preterm

PubMed Central

Omizzolo, Cristina; Scratch, Shannon E; Stargatt, Robyn; Kidokoro, Hiroyuki; Thompson, Deanne K; Lee, Katherine J; Cheong, Jeanie; Neil, Jeffrey; Inder, Terrie E; Doyle, Lex W; Anderson, Peter J

2014-01-01

Using prospective longitudinal data from 198 very preterm and 70 full term children, this study characterised the memory and learning abilities of very preterm children at 7 years of age in both verbal and visual domains. The relationship between the extent of brain abnormalities on neonatal magnetic resonance imaging (MRI) and memory and learning outcomes at 7 years of age in very preterm children was also investigated. Neonatal MRI scans were qualitatively assessed for global, white-matter, cortical grey-matter, deep grey-matter, and cerebellar abnormalities. Very preterm children performed less well on measures of immediate memory, working memory, long-term memory, and learning compared with term born controls. Neonatal brain abnormalities, and in particular deep grey matter abnormality, were associated with poorer memory and learning performance at 7 years in very preterm children, especially global, white-matter, grey-matter and cerebellar abnormalities. Findings support the importance of cerebral neonatal pathology for predicting later memory and learning function. PMID:23805915

Optimized Infrastructure for the Earth System Prediction Capability

DTIC Science & Technology

2013-09-30

for referencing memory between its native coupling datatype (MCT Attribute Vectors) and ESMF Arrays. This will reduce the copies required and will...introduced ability within CESM to share memory between ESMF and MCT datatypes makes using both tools together much easier. Using both is appealing

Infectious Cognition: Risk Perception Affects Socially Shared Retrieval-Induced Forgetting of Medical Information.

PubMed

Coman, Alin; Berry, Jessica N

2015-12-01

When speakers selectively retrieve previously learned information, listeners often concurrently, and covertly, retrieve their memories of that information. This concurrent retrieval typically enhances memory for mentioned information (the rehearsal effect) and impairs memory for unmentioned but related information (socially shared retrieval-induced forgetting, SSRIF), relative to memory for unmentioned and unrelated information. Building on research showing that anxiety leads to increased attention to threat-relevant information, we explored whether concurrent retrieval is facilitated in high-anxiety real-world contexts. Participants first learned category-exemplar facts about meningococcal disease. Following a manipulation of perceived risk of infection (low vs. high risk), they listened to a mock radio show in which some of the facts were selectively practiced. Final recall tests showed that the rehearsal effect was equivalent between the two risk conditions, but SSRIF was significantly larger in the high-risk than in the low-risk condition. Thus, the tendency to exaggerate consequences of news events was found to have deleterious consequences. © The Author(s) 2015.

Fencing direct memory access data transfers in a parallel active messaging interface of a parallel computer

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

Blocksome, Michael A.; Mamidala, Amith R.

2013-09-03

Fencing direct memory access (`DMA`) data transfers in a parallel active messaging interface (`PAMI`) of a parallel computer, the PAMI including data communications endpoints, each endpoint including specifications of a client, a context, and a task, the endpoints coupled for data communications through the PAMI and through DMA controllers operatively coupled to segments of shared random access memory through which the DMA controllers deliver data communications deterministically, including initiating execution through the PAMI of an ordered sequence of active DMA instructions for DMA data transfers between two endpoints, effecting deterministic DMA data transfers through a DMA controller and a segmentmore » of shared memory; and executing through the PAMI, with no FENCE accounting for DMA data transfers, an active FENCE instruction, the FENCE instruction completing execution only after completion of all DMA instructions initiated prior to execution of the FENCE instruction for DMA data transfers between the two endpoints.« less

Rapid allergen-induced interleukin-17 and interferon-γ secretion by skin-resident memory CD8+ T cells.

PubMed

Schmidt, Jonas D; Ahlström, Malin G; Johansen, Jeanne D; Dyring-Andersen, Beatrice; Agerbeck, Christina; Nielsen, Morten M; Poulsen, Steen S; Woetmann, Anders; Ødum, Niels; Thomsen, Allan R; Geisler, Carsten; Bonefeld, Charlotte M

2017-04-01

Skin-resident memory T (T RM ) cells are associated with immunological memory in the skin. Whether immunological memory responses to allergens in the skin are solely localized to previously allergen-exposed sites or are present globally in the skin is not clear. Furthermore, the mechanisms whereby T RM cells induce rapid recall responses need further investigation. To study whether contact allergens induce local and/or global memory, and to determine the mechanisms involved in memory responses in the skin. To address these questions, we analysed responses to contact allergens in mice and humans sensitized to 2,4-dinitrofluorobenzene and nickel, respectively. Challenge responses in both mice and humans were dramatically increased at sites previously exposed to allergens as compared with previously unexposed sites. Importantly, the magnitude of the challenge response correlated with the epidermal accumulation of interleukin (IL)-17A-producing and interferon (IFN)-γ-producing T RM cells. Moreover, IL-17A and IFN-γ enhanced allergen-induced IL-1β production in keratinocytes. We show that sensitization with contact allergens induces a strong, long-lasting local memory and a weaker, temporary global immunological memory response to the allergen that is mediated by IL-17A-producing and IFN-γ-producing CD8 + T RM cells. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Neuropsychological and SPECT scan findings during and after transient global amnesia: evidence for the differential impairment of remote episodic memory.

PubMed

Evans, J; Wilson, B; Wraight, E P; Hodges, J R

1993-11-01

A patient had neuropsychological testing during, and at two days and seven weeks after a transient global amnesia (TGA) attack. During the attack she exhibited a characteristically profound anterograde amnesia but a limited remote memory loss; the most striking impairment was a deficit in personal episodic memory revealed by her performance on the Autobiographical Memory Interview. Personal and general semantic information was less impaired although there were indications of a temporal gradient in the impairment. When tested after the attack, she demonstrated normal anterograde and retrograde memory. A SPECT scan performed during TGA showed a focal reduction in cerebral perfusion in the postero-medial temporal lobes bilaterally which had resolved after seven weeks.

The Work's Not Over- Roll Up Your Sleeves and Make a Difference!

NASA Astrophysics Data System (ADS)

Sarquis, Mickey

1997-01-01

As my 17-year tenure as the first editor of the Secondary School Chemistry Section draws to a close, John Moore has invited me to share some reflections on my experiences. It's hard for me to believe that this many years have passed; in some ways, it seems like only yesterday that I took on this position. Looking back over my term as Section editor recalls wonderful memories, but it also stimulates me to seek out and take on new challenges as I move into a new phase of involvement in chemical education. In response to John's kind invitation, I'd like to share some of these memories and ideas with you who share my vision of quality chemical education, particularly at the secondary level.

Arousal-biased competition in perception and memory

PubMed Central

Mather, Mara; Sutherland, Matthew R.

2010-01-01

Our everyday surroundings besiege us with information. The battle is for a share of our limited attention and memory, with the brain selecting the winners and discarding the losers. Previous research shows that both bottom-up and top-down factors bias competition in favor of high priority stimuli. We propose that arousal during an event increases this bias both in perception and in long-term memory of the event. Arousal-biased competition theory provides specific predictions about when arousal will enhance and when it will impair memory for events, accounting for some puzzling contradictions in the emotional memory literature. PMID:21660127

Neutral and emotional episodic memory: global impairment after lorazepam or scopolamine.

PubMed

Kamboj, Sunjeev K; Curran, H Valerie

2006-11-01

Benzodiazepines and anticholinergic drugs have repeatedly been shown to impair episodic memory for emotionally neutral material in humans. However, their effect on memory for emotionally laden stimuli has been relatively neglected. We sought to investigate the effects of the benzodiazepine, lorazepam, and the anticholinergic, scopolamine, on incidental episodic memory for neutral and emotional components of a narrative memory task in humans. A double-blind, placebo-controlled independent group design was used with 48 healthy volunteers to examine the effects of these drugs on emotional and neutral episodic memory. As expected, the emotional memory advantage was retained for recall and recognition memory under placebo conditions. However, lorazepam and scopolamine produced anterograde recognition memory impairments on both the neutral and emotional components of the narrative, although floor effects were obtained for recall memory. Furthermore, compared with placebo, recognition memory for both central (gist) and peripheral (detail) aspects of neutral and emotional elements of the narrative was poorer after either drug. Benzodiazepine-induced GABAergic enhancement or scopolamine-induced cholinergic hypofunction results in a loss of the enhancing effect of emotional arousal on memory. Furthermore, lorazepam- and scopolamine-induced memory impairment for both gist (which is amygdala dependent) and detail raises the possibility that their effects on emotional memory do not depend only on the amygdala. We discuss the results with reference to potential clinical/forensic implications of processing emotional memories under conditions of globally impaired episodic memory.

Glucocorticoids in the prefrontal cortex enhance memory consolidation and impair working memory by a common neural mechanism

PubMed Central

Barsegyan, Areg; Mackenzie, Scott M.; Kurose, Brian D.; McGaugh, James L.; Roozendaal, Benno

2010-01-01

It is well established that acute administration of adrenocortical hormones enhances the consolidation of memories of emotional experiences and, concurrently, impairs working memory. These different glucocorticoid effects on these two memory functions have generally been considered to be independently regulated processes. Here we report that a glucocorticoid receptor agonist administered into the medial prefrontal cortex (mPFC) of male Sprague-Dawley rats both enhances memory consolidation and impairs working memory. Both memory effects are mediated by activation of a membrane-bound steroid receptor and depend on noradrenergic activity within the mPFC to increase levels of cAMP-dependent protein kinase. These findings provide direct evidence that glucocorticoid effects on both memory consolidation and working memory share a common neural influence within the mPFC. PMID:20810923

Benefits and Costs of Context Reinstatement in Episodic Memory: An ERP Study.

PubMed

Bramão, Inês; Johansson, Mikael

2017-01-01

This study investigated context-dependent episodic memory retrieval. An influential idea in the memory literature is that performance benefits when the retrieval context overlaps with the original encoding context. However, such memory facilitation may not be driven by the encoding-retrieval overlap per se but by the presence of diagnostic features in the reinstated context that discriminate the target episode from competing episodes. To test this prediction, the encoding-retrieval overlap and the diagnostic value of the context were manipulated in a novel associative recognition memory task. Participants were asked to memorize word pairs presented together with diagnostic (unique) and nondiagnostic (shared) background scenes. At test, participants recognized the word pairs in the presence and absence of the previously encoded contexts. Behavioral data show facilitated memory performance in the presence of the original context but, importantly, only when the context was diagnostic of the target episode. The electrophysiological data reveal an early anterior ERP encoding-retrieval overlap effect that tracks the cost associated with having nondiagnostic contexts present at retrieval, that is, shared by multiple previous episodes, and a later posterior encoding-retrieval overlap effect that reflects facilitated access to the target episode during retrieval in diagnostic contexts. Taken together, our results underscore the importance of the diagnostic value of the context and suggest that context-dependent episodic memory effects are multiple determined.

Sharing Data in the Global Ocean Observing System (Invited)

NASA Astrophysics Data System (ADS)

Lindstrom, E. J.; McCurdy, A.; Young, J.; Fischer, A. S.

2010-12-01

We examine the evolution of data sharing in the field of physical oceanography to highlight the challenges now before us. Synoptic global observation of the ocean from space and in situ platforms has significantly matured over the last two decades. In the early 1990’s the community data sharing challenges facing the World Ocean Circulation Experiment (WOCE) largely focused on the behavior of individual scientists. Satellite data sharing depended on the policy of individual agencies. Global data sets were delivered with considerable delay and with enormous personal sacrifice. In the 2000’s the requirements for global data sets and sustained observations from the likes of the U.N. Framework Convention on Climate Change have led to data sharing and cooperation at a grander level. It is more effective and certainly more efficient. The Joint WMO/IOC Technical Commission on Oceanography and Marine Meteorology (JCOMM) provided the means to organize many aspects of data collection and data dissemination globally, for the common good. In response the Committee on Earth Observing Satellites organized Virtual Constellations to enable the assembly and sharing of like kinds of satellite data (e.g., sea surface topography, ocean vector winds, and ocean color). Individuals in physical oceanography have largely adapted to the new rigors of sharing data for the common good, and as a result of this revolution new science has been enabled. Primary obstacles to sharing have shifted from the individual level to the national level. As we enter into the 2010’s the demands for ocean data continue to evolve with an expanded requirement for more real-time reporting and broader disciplinary coverage, to answer key scientific and societal questions. We are also seeing the development of more numerous national contributions to the global observing system. The drivers for the establishment of global ocean observing systems are expanding beyond climate to include biological and biogeochemical issues (e.g. biodiversity and ecosystem services, fisheries collapse, and ocean acidification). This expanded suite of demands and drivers challenge us further to share data for the common good across specialties. This requires that more ocean scientific communities and national ocean observing programs move towards maturity in terms of global data collection capability, sharing capacity, and data management standards. In oceanography the time has arrived for a cultural shift toward more shared collective observing capabilities. Necessarily we must also rapidly move toward harmony in national data sharing policies for the ocean environment. Building capacity to share ocean observations has been an objective for decades and has resulted in an expanded understanding of technologies and management policies that foster data sharing and provenance tracking.

Hypercluster - Parallel processing for computational mechanics

NASA Technical Reports Server (NTRS)

Blech, Richard A.

1988-01-01

An account is given of the development status, performance capabilities and implications for further development of NASA-Lewis' testbed 'hypercluster' parallel computer network, in which multiple processors communicate through a shared memory. Processors have local as well as shared memory; the hypercluster is expanded in the same manner as the hypercube, with processor clusters replacing the normal single processor node. The NASA-Lewis machine has three nodes with a vector personality and one node with a scalar personality. Each of the vector nodes uses four board-level vector processors, while the scalar node uses four general-purpose microcomputer boards.

Contributions of Medial Temporal Lobe and Striatal Memory Systems to Learning and Retrieving Overlapping Spatial Memories

PubMed Central

Brown, Thackery I.; Stern, Chantal E.

2014-01-01

Many life experiences share information with other memories. In order to make decisions based on overlapping memories, we need to distinguish between experiences to determine the appropriate behavior for the current situation. Previous work suggests that the medial temporal lobe (MTL) and medial caudate interact to support the retrieval of overlapping navigational memories in different contexts. The present study used functional magnetic resonance imaging (fMRI) in humans to test the prediction that the MTL and medial caudate play complementary roles in learning novel mazes that cross paths with, and must be distinguished from, previously learned routes. During fMRI scanning, participants navigated virtual routes that were well learned from prior training while also learning new mazes. Critically, some routes learned during scanning shared hallways with those learned during pre-scan training. Overlap between mazes required participants to use contextual cues to select between alternative behaviors. Results demonstrated parahippocampal cortex activity specific for novel spatial cues that distinguish between overlapping routes. The hippocampus and medial caudate were active for learning overlapping spatial memories, and increased their activity for previously learned routes when they became context dependent. Our findings provide novel evidence that the MTL and medial caudate play complementary roles in the learning, updating, and execution of context-dependent navigational behaviors. PMID:23448868

Symbiosis of executive and selective attention in working memory

PubMed Central

Vandierendonck, André

2014-01-01

The notion of working memory (WM) was introduced to account for the usage of short-term memory resources by other cognitive tasks such as reasoning, mental arithmetic, language comprehension, and many others. This collaboration between memory and other cognitive tasks can only be achieved by a dedicated WM system that controls task coordination. To that end, WM models include executive control. Nevertheless, other attention control systems may be involved in coordination of memory and cognitive tasks calling on memory resources. The present paper briefly reviews the evidence concerning the role of selective attention in WM activities. A model is proposed in which selective attention control is directly linked to the executive control part of the WM system. The model assumes that apart from storage of declarative information, the system also includes an executive WM module that represents the current task set. Control processes are automatically triggered when particular conditions in these modules are met. As each task set represents the parameter settings and the actions needed to achieve the task goal, it will depend on the specific settings and actions whether selective attention control will have to be shared among the active tasks. Only when such sharing is required, task performance will be affected by the capacity limits of the control system involved. PMID:25152723

Symbiosis of executive and selective attention in working memory.

PubMed

Vandierendonck, André

2014-01-01

The notion of working memory (WM) was introduced to account for the usage of short-term memory resources by other cognitive tasks such as reasoning, mental arithmetic, language comprehension, and many others. This collaboration between memory and other cognitive tasks can only be achieved by a dedicated WM system that controls task coordination. To that end, WM models include executive control. Nevertheless, other attention control systems may be involved in coordination of memory and cognitive tasks calling on memory resources. The present paper briefly reviews the evidence concerning the role of selective attention in WM activities. A model is proposed in which selective attention control is directly linked to the executive control part of the WM system. The model assumes that apart from storage of declarative information, the system also includes an executive WM module that represents the current task set. Control processes are automatically triggered when particular conditions in these modules are met. As each task set represents the parameter settings and the actions needed to achieve the task goal, it will depend on the specific settings and actions whether selective attention control will have to be shared among the active tasks. Only when such sharing is required, task performance will be affected by the capacity limits of the control system involved.

Identification of a Functional Connectome for Long-Term Fear Memory in Mice

PubMed Central

Wheeler, Anne L.; Teixeira, Cátia M.; Wang, Afra H.; Xiong, Xuejian; Kovacevic, Natasa; Lerch, Jason P.; McIntosh, Anthony R.; Parkinson, John; Frankland, Paul W.

2013-01-01

Long-term memories are thought to depend upon the coordinated activation of a broad network of cortical and subcortical brain regions. However, the distributed nature of this representation has made it challenging to define the neural elements of the memory trace, and lesion and electrophysiological approaches provide only a narrow window into what is appreciated a much more global network. Here we used a global mapping approach to identify networks of brain regions activated following recall of long-term fear memories in mice. Analysis of Fos expression across 84 brain regions allowed us to identify regions that were co-active following memory recall. These analyses revealed that the functional organization of long-term fear memories depends on memory age and is altered in mutant mice that exhibit premature forgetting. Most importantly, these analyses indicate that long-term memory recall engages a network that has a distinct thalamic-hippocampal-cortical signature. This network is concurrently integrated and segregated and therefore has small-world properties, and contains hub-like regions in the prefrontal cortex and thalamus that may play privileged roles in memory expression. PMID:23300432

Transient global amnesia—a hippocampal phenomenon?

PubMed Central

Ponsford, J L; Donnan, G A

1980-01-01

A case of transient global amnesia of clear vascular aetiology is described. Results of neuropsychological testing carried out during the attack clarify the nature of the memory disorder and suggest that the critical region of ischaemia is the medial temporal area around the hippocampus. Follow-up testing suggests that no lasting memory impairment resulted. PMID:7373328

The prevalence and quality of silent, socially silent, and disclosed autobiographical memories across adulthood.

PubMed

Alea, Nicole

2010-02-01

Two separate studies examined the prevalence and quality of silent (infrequently recalled), socially silent (i.e., recalled but not shared), and disclosed autobiographical memories. In Study 1 young and older men and women remembered positive events. Positive memories were more likely to be disclosed than to be kept socially silent or completely silent. However, socially silent and disclosed memories did not differ in memory quality: the memories were equally vivid, significant, and emotional. Silent memories were less qualitatively rich. This pattern of results was generally replicated in Study 2 with a lifespan sample for both positive and negative memories, and with additional qualitative variables. The exception was that negative memories were kept silent more often. Age differences were minimal. Women disclosed their autobiographical memories more, but men told a greater variety of people. Results are discussed in terms of the functions that memory telling and silences might serve for individuals.

Researching the Habitus of Global Policy Actors in Education

ERIC Educational Resources Information Center

Lingard, Bob; Sellar, Sam; Baroutsis, Aspa

2015-01-01

This paper reprises the argument for the emergence of a global education policy field and then focuses on the shared habitus of global and national policy actors and technicians. It is argued that this shared habitus is constituted as a reflection of and a contribution to the creation of the global education policy field. Bourdieu's approach to…

Developmental changes in real life decision making: performance on a gambling task previously shown to depend on the ventromedial prefrontal cortex.

PubMed

Crone, Eveline A; van der Molen, Maurits W

2004-01-01

Patients with bilateral lesions of the ventromedial prefrontal cortex, when performing gambling tasks modeling real-life decision-making, opt for choices that yield high immediate gains in spite of higher future losses. Under the hypothesis that the prefrontal cortex is the last brain region to mature, it was examined whether young children would show a similar preference for immediate prospects. In Experiment 1, 4 age groups (6-9, 10-12, 13-15 and 18-25 years olds) performed 2 versions of a computerized variant of the original Iowa gambling task under 3 different feedback conditions (no feedback, global feedback, and option-specific feedback) and completed the Raven Standard Progressive Matrices as an index of inductive reasoning ability. In Experiment 2, 3 age groups (7-8, 11-12, and 15-16 year olds) performed both task versions in addition to a working memory task ("Digit Span Backwards"). Results showed a developmental increase in the sensitivity to future consequences, positive or negative, that could not be explained by developmental changes in working memory capacity or inductive reasoning. It was concluded that young children share with ventromedial prefrontal patients the failure to anticipate on future outcomes.

Cognition in school-aged children with "active" epilepsy: A population-based study.

PubMed

Reilly, Colin; Atkinson, Patricia; Das, Krishna B; Chin, Richard F M; Aylett, Sarah E; Burch, Victoria; Gillberg, Christopher; Scott, Rod C; Neville, Brian G R

2015-01-01

There is a lack of population-based data on specific cognitive profiles in childhood epilepsy. This study sought to determine the frequency of impairments in global cognition and aspects of working memory and processing speed in a population-based sample of children with "active" epilepsy (on antiepileptic Drugs (AEDs), and/or had a seizure in the last year). Factors significantly associated with global and specific difficulties in cognition were also identified. A total of 85 (74% of eligible population) school-aged children (5-15 years) with "active" epilepsy underwent comprehensive psychological assessment including assessment of global cognition, working memory, and processing speed. Scores on cognitive subtests were compared via paired-samples t tests. The factors associated with cognitive difficulties were analyzed via linear regression. A total of 24% of children were functioning below IQ 50, and 40% had IQ scores below 70. Scores on the Processing Speed Index were significantly lower than scores on the Verbal or Performance indexes on Wechsler instruments. The Coding subtest was a significant weakness compared with the other Wechsler subtests. A total of 58% of children displayed "memory underachievement" (memory score 1 SD below assessed IQ) on at least one of the four administered working memory subtests. Factors significantly associated with globally impaired cognition included being on polytherapy (β = -13.0; 95% CI [-19.3, -6.6], p = .000) and having attention-deficit/hyperactivity disorder (ADHD; β = -11.1, 95% CI [-3.0, -19.3], p = .008). Being on polytherapy was also associated with lower scores on the working memory and processing speed composite scores. Having developmental coordination disorder (DCD) was associated with a lower score on the processing speed composite. There is a high rate of global and specific cognitive difficulties in childhood epilepsy. Difficulties are most pronounced in aspects of working memory and processing speed. Predictors of cognitive impairment in childhood epilepsy include epilepsy-related and behavioral factors, which may differ depending on the domain of cognition assessed.

Personal semantics: at the crossroads of semantic and episodic memory.

PubMed

Renoult, Louis; Davidson, Patrick S R; Palombo, Daniela J; Moscovitch, Morris; Levine, Brian

2012-11-01

Declarative memory is usually described as consisting of two systems: semantic and episodic memory. Between these two poles, however, may lie a third entity: personal semantics (PS). PS concerns knowledge of one's past. Although typically assumed to be an aspect of semantic memory, it is essentially absent from existing models of knowledge. Furthermore, like episodic memory (EM), PS is idiosyncratically personal (i.e., not culturally-shared). We show that, depending on how it is operationalized, the neural correlates of PS can look more similar to semantic memory, more similar to EM, or dissimilar to both. We consider three different perspectives to better integrate PS into existing models of declarative memory and suggest experimental strategies for disentangling PS from semantic and episodic memory. Copyright © 2012 Elsevier Ltd. All rights reserved.

Etiological Distinction of Working Memory Components in Relation to Mathematics

PubMed Central

Lukowski, Sarah L.; Soden, Brooke; Hart, Sara A.; Thompson, Lee A.; Kovas, Yulia; Petrill, Stephen A.

2014-01-01

Working memory has been consistently associated with mathematics achievement, although the etiology of these relations remains poorly understood. The present study examined the genetic and environmental underpinnings of math story problem solving, timed calculation, and untimed calculation alongside working memory components in 12-year-old monozygotic (n = 105) and same-sex dizygotic (n = 143) twin pairs. Results indicated significant phenotypic correlation between each working memory component and all mathematics outcomes (r = 0.18 – 0.33). Additive genetic influences shared between the visuo-spatial sketchpad and mathematics achievement was significant, accounting for roughly 89% of the observed correlation. In addition, genetic covariance was found between the phonological loop and math story problem solving. In contrast, despite there being a significant observed relationship between phonological loop and timed and untimed calculation, there was no significant genetic or environmental covariance between the phonological loop and timed or untimed calculation skills. Further analyses indicated that genetic overlap between the visuo-spatial sketchpad and math story problem solving and math fluency was distinct from general genetic factors, whereas g, phonological loop, and mathematics shared generalist genes. Thus, although each working memory component was related to mathematics, the etiology of their relationships may be distinct. PMID:25477699

Frequency Monitoring: A Methodology for Assessing the Organization of Information

DTIC Science & Technology

1988-08-01

Memory & Cognition, 6, 410-415. Tulving, E. Episodic and semantic memory (1972). In E. Tulving & W. Donaldson (Ed.), Organization and memory . New...are stored in episodic memory (Tulving, 1972). These global-level memory units enable people to make important decisions about such significant... semantically similar. However, as indicated earlier, an advantage of frequency-estimation tests of memory is that they do not require the presentation of

Test Sequence Priming in Recognition Memory

ERIC Educational Resources Information Center

Johns, Elizabeth E.; Mewhort, D. J. K.

2009-01-01

The authors examined priming within the test sequence in 3 recognition memory experiments. A probe primed its successor whenever both probes shared a feature with the same studied item ("interjacent priming"), indicating that the study item like the probe is central to the decision. Interjacent priming occurred even when the 2 probes did…

Two Maintenance Mechanisms of Verbal Information in Working Memory

ERIC Educational Resources Information Center

Camos, V.; Lagner, P.; Barrouillet, P.

2009-01-01

The present study evaluated the interplay between two mechanisms of maintenance of verbal information in working memory, namely articulatory rehearsal as described in Baddeley's model, and attentional refreshing as postulated in Barrouillet and Camos's Time-Based Resource-Sharing (TBRS) model. In four experiments using complex span paradigm, we…

Down Memory Lane: Recollections of Lamaze International's First 50 Years

PubMed Central

Zwelling, Elaine

2010-01-01

The 42-year involvement of one member of Lamaze International is chronicled through a decade-by-decade review of personal memories. The history of Lamaze International is shared through the recollections of her roles as a childbirth educator, faculty member, and member of the board of directors. PMID:21629385

Paul Ricoeur, Memory, and the Historical Gaze: Implications for Education Histories

ERIC Educational Resources Information Center

Colby, Sherri Rae

2012-01-01

In this article, the author shares the potential applications of Paul Ricoeur's philosophies of history, memory, and narrative to the interpretation of educational histories, and those histories' life spans: moving cyclically from early conception, to evidentiary construction, to published dissemination; and ultimately to death or immortality. Her…

The DASH Project: An Overview

DTIC Science & Technology

1988-02-29

by memory copyin g will degrade system performance on shared-memory multiprocessors. Virtual memor y (VM) remapping, as opposed to memory copying...Bershad, G.D. Giuseppe Facchetti, Kevin Fall, G . Scott Graham, Ellen Nelson , P. Venkat Rangan, Bruno Sartirana, Shin-Yuan Tzou, Raj Vaswani, and Robert...Remote Execution in NEST", IEEE Trans. on Software Eng. 13, 8 (August 1987), 905-912. 3. G . T. Almes, A. P. Black, E. Lazowska and J. Noe, "The Eden

Alzheimer's Disease Can Spare Local Metacognition Despite Global Anosognosia: Revisiting the Confidence-Accuracy Relationship in Episodic Memory

ERIC Educational Resources Information Center

Gallo, David A.; Cramer, Stefanie J.; Wong, Jessica T.; Bennett, David A.

2012-01-01

Alzheimer's disease (AD) can impair metacognition in addition to more basic cognitive functions like memory. However, while global metacognitive inaccuracies are well documented (i.e., low deficit awareness, or anosognosia), the evidence is mixed regarding the effects of AD on local or task-based metacognitive judgments. Here we investigated local…

[Efficacy of frequency-neurofeedback and Cogmed JM-working memory training in children with ADHD].

PubMed

van Dongen-Boomsma, M; Vollebregt, M A; Slaats-Willemse, D; Buitelaar, J K

2015-01-01

The need for and the interest in non-pharmacological treatments for children with ADHD are increasing. The treatments include electro-encephalogram (EEG) frequency-neurofeedback and Cogmed working memory training. To investigate the efficacy of frequency-neurofeedback and Cogmed working memory training in children with ADHD. Forty-one children with ADHD (aged 8-15 years) were assigned to frequency-neurofeedback or to placebo-neurofeedback in a randomized double-blind trial. We took measurements to find out whether frequency-neurofeedback had reduced the severity of the ADHD-symptoms, and/or had improved neurocognitive ability and global clinical functioning. Fifty-one children with ADHD (aged 5-7 years) were assigned to the active Cogmed JM-working memory training or to the placebo working memory training in a randomised double-blind trial. We took measurements to find out whether Cogmed JM-working memory training had reduced the ADHD symptoms, and/or had improved neurocognitive ability, daily performance and global clinical functioning. The ADHD symptoms and global clinical functioning of the children in both neurofeedback groups improved. However, frequency-neurofeedback did nor produce any significantly better treatment results than did the placebo neurofeedback. At the neurocognitive level, frequency-neurofeedback did not yield any measurements that were significantly superior to those achieved with placebo feedback. Various outcome measurements improved in both groups with memory training. However, the active working memory training was not found to have produced significantly better results than the placebo training with regards to the ADHD symptoms, neurocognitive ability and daily and global functioning. Children from the active working memory training group showed improvements in trained working memory tasks but not on untrained tasks. Neither study produced any conclusive evidence for the efficacy of the investigated treatments in children with ADHD. However, both types of treatments can be further improved. Furthermore, the controlled designs may have restricted the embedding of the treatments. Because of possible improvements in the treatments in the future and because of the design restrictions affecting the treatments in their present form, it is still too early to draw any definitive conclusions about the validity and advantages of the two treatment methods.

Shared wilderness, shared responsibility, shared vision: Protecting migratory wildlife

Treesearch

Will Meeks; Jimmy Fox; Nancy Roeper

2011-01-01

Wilderness plays a vital role in global and landscape-level conservation of wildlife. Millions of migratory birds and mammals rely on wilderness lands and waters during critical parts of their life. As large, ecologically intact landscapes, wilderness areas also play a vital role in addressing global climate change by increasing carbon sequestration, reducing...

Fronto-parietal and cingulo-opercular network integrity and cognition in health and schizophrenia

PubMed Central

Sheffield, Julia M; Repovs, Grega; Harms, Michael P.; Carter, Cameron S.; Gold, James M.; MacDonald, Angus W.; Ragland, J. Daniel; Silverstein, Steven M.; Godwin, Douglass; Barch, Deanna M

2015-01-01

Growing evidence suggests that coordinated activity within specific functional brain networks supports cognitive ability, and that abnormalities in brain connectivity may underlie cognitive deficits observed in neuropsychiatric diseases, such as schizophrenia. Two functional networks, the fronto-parietal network (FPN) and cingulo-opercular network (CON), are hypothesized to support top-down control of executive functioning, and have therefore emerged as potential drivers of cognitive impairment in disease-states. Graph theoretic analyses of functional connectivity data can characterize network topology, allowing the relationships between cognitive ability and network integrity to be examined. In the current study we applied graph analysis to pseudo-resting state data in 54 healthy subjects and 46 schizophrenia patients, and measured overall cognitive ability as the shared variance in performance from tasks of episodic memory, verbal memory, processing speed, goal maintenance, and visual integration. We found that, across all participants, cognitive ability was significantly positively associated with the local and global efficiency of the whole brain, FPN, and CON, but not with the efficiency of a comparison network, the auditory network. Additionally, the participation coefficient of the right anterior insula, a major hub within the CON, significantly predicted cognition, and this relationship was independent of CON global efficiency. Surprisingly, we did not observe strong evidence for group differences in any of our network metrics. These data suggest that functionally efficient task control networks support better cognitive ability in both health and schizophrenia, and that the right anterior insula may be a particularly important hub for successful cognitive performance across both health and disease. PMID:25979608

Memory-focused interventions for people with cognitive disorders: A systematic review and meta-analysis of randomized controlled studies.

PubMed

Yang, Hui-Ling; Chan, Pi-Tuan; Chang, Pi-Chen; Chiu, Huei-Ling; Sheen Hsiao, Shu-Tai; Chu, Hsin; Chou, Kuei-Ru

2018-02-01

A better understanding of people with cognitive disorders improves performance on memory tasks through memory-focused interventions are needed. The purpose of this study was to assess the effect of memoryfocused interventions on cognitive disorders through a meta-analysis. Systematic review and meta-analysis. The online electronic databases PubMed, the Cochrane Library, Ovid-Medline, CINHAL, PsycINFO, Ageline, and Embase (up to May 2017) were used in this study. No language restriction was applied to the search. Objective memory (learning and memory function, immediate recall, delayed recall, and recognition) was the primary indicator and subjective memory performance, global cognitive function, and depression were the secondary indicators. The Hedges' g of change, subgroup analyses, and meta-regression were analyzed on the basis of the characteristics of people with cognitive disorders. A total of 27 studies (2177 participants, mean age=75.80) reporting RCTs were included in the meta-analysis. The results indicated a medium-to-large effect of memory-focused interventions on learning and memory function (Hedges' g=0.62) and subjective memory performance (Hedges' g=0.67), a small-to-medium effect on delayed recall and depression, and a small effect on immediate recall and global cognitive function (all p<0.05) compared with the control. Subgroup analysis and meta-regression indicated that the effects on learning and memory function were more profound in the format of memory training, individual training, shorter treatment duration, and more than eight treatment sessions, and the effect size indicated the MMSE score was the most crucial indicator (β=-0.06, p=0.04). This is first comprehensive meta-analysis of special memory domains in people with cognitive disorders. The results revealed that memory-focused interventions effectively improved memory-related performance in people with cognitive disorders. An appropriately designed intervention can effectively improve memory function, reduce disability progression, and improve mood state in people with cognitive disorders. Additional randomized controlled trials including measures of recognition, global cognitive function, and depression should be conducted and analyzed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Neural pattern similarity underlies the mnemonic advantages for living words.

PubMed

Xiao, Xiaoqian; Dong, Qi; Chen, Chuansheng; Xue, Gui

2016-06-01

It has been consistently shown that words representing living things are better remembered than words representing nonliving things, yet the underlying cognitive and neural mechanisms have not been clearly elucidated. The present study used both univariate and multivariate pattern analyses to examine the hypotheses that living words are better remembered because (1) they draw more attention and/or (2) they share more overlapping semantic features. Subjects were asked to study a list of living and nonliving words during a semantic judgment task. An unexpected recognition test was administered 30 min later. We found that subjects recognized significantly more living words than nonliving words. Results supported the overlapping semantic feature hypothesis by showing that (a) semantic ratings showed greater semantic similarity for living words than for nonliving words, (b) there was also significantly greater neural global pattern similarity (nGPS) for living words than for nonliving words in the posterior portion of left parahippocampus (LpPHG), (c) the nGPS in the LpPHG reflected the rated semantic similarity, and also mediated the memory differences between two semantic categories, and (d) greater univariate activation was found for living words than for nonliving words in the left hippocampus (LHIP), which mediated the better memory performance for living words and might reflect greater semantic context binding. In contrast, although living words were processed faster and elicited a stronger activity in the dorsal attention network, these differences did not mediate the animacy effect in memory. Taken together, our results provide strong support to the overlapping semantic features hypothesis, and emphasize the important role of semantic organization in episodic memory encoding. Copyright © 2016 Elsevier Ltd. All rights reserved.

A community effort to protect genomic data sharing, collaboration and outsourcing.

PubMed

Wang, Shuang; Jiang, Xiaoqian; Tang, Haixu; Wang, Xiaofeng; Bu, Diyue; Carey, Knox; Dyke, Stephanie Om; Fox, Dov; Jiang, Chao; Lauter, Kristin; Malin, Bradley; Sofia, Heidi; Telenti, Amalio; Wang, Lei; Wang, Wenhao; Ohno-Machado, Lucila

2017-01-01

The human genome can reveal sensitive information and is potentially re-identifiable, which raises privacy and security concerns about sharing such data on wide scales. In 2016, we organized the third Critical Assessment of Data Privacy and Protection competition as a community effort to bring together biomedical informaticists, computer privacy and security researchers, and scholars in ethical, legal, and social implications (ELSI) to assess the latest advances on privacy-preserving techniques for protecting human genomic data. Teams were asked to develop novel protection methods for emerging genome privacy challenges in three scenarios: Track (1) data sharing through the Beacon service of the Global Alliance for Genomics and Health. Track (2) collaborative discovery of similar genomes between two institutions; and Track (3) data outsourcing to public cloud services. The latter two tracks represent continuing themes from our 2015 competition, while the former was new and a response to a recently established vulnerability. The winning strategy for Track 1 mitigated the privacy risk by hiding approximately 11% of the variation in the database while permitting around 160,000 queries, a significant improvement over the baseline. The winning strategies in Tracks 2 and 3 showed significant progress over the previous competition by achieving multiple orders of magnitude performance improvement in terms of computational runtime and memory requirements. The outcomes suggest that applying highly optimized privacy-preserving and secure computation techniques to safeguard genomic data sharing and analysis is useful. However, the results also indicate that further efforts are needed to refine these techniques into practical solutions.

Initial Performance Results on IBM POWER6

NASA Technical Reports Server (NTRS)

Saini, Subbash; Talcott, Dale; Jespersen, Dennis; Djomehri, Jahed; Jin, Haoqiang; Mehrotra, Piysuh

2008-01-01

The POWER5+ processor has a faster memory bus than that of the previous generation POWER5 processor (533 MHz vs. 400 MHz), but the measured per-core memory bandwidth of the latter is better than that of the former (5.7 GB/s vs. 4.3 GB/s). The reason for this is that in the POWER5+, the two cores on the chip share the L2 cache, L3 cache and memory bus. The memory controller is also on the chip and is shared by the two cores. This serializes the path to memory. For consistently good performance on a wide range of applications, the performance of the processor, the memory subsystem, and the interconnects (both latency and bandwidth) should be balanced. Recognizing this, IBM has designed the Power6 processor so as to avoid the bottlenecks due to the L2 cache, memory controller and buffer chips of the POWER5+. Unlike the POWER5+, each core in the POWER6 has its own L2 cache (4 MB - double that of the Power5+), memory controller and buffer chips. Each core in the POWER6 runs at 4.7 GHz instead of 1.9 GHz in POWER5+. In this paper, we evaluate the performance of a dual-core Power6 based IBM p6-570 system, and we compare its performance with that of a dual-core Power5+ based IBM p575+ system. In this evaluation, we have used the High- Performance Computing Challenge (HPCC) benchmarks, NAS Parallel Benchmarks (NPB), and four real-world applications--three from computational fluid dynamics and one from climate modeling.

Towards Social Radiology as an Information Infrastructure: Reconciling the Local With the Global

PubMed Central

2014-01-01

The current widespread use of medical images and imaging procedures in clinical practice and patient diagnosis has brought about an increase in the demand for sharing medical imaging studies among health professionals in an easy and effective manner. This article reveals the existence of a polarization between the local and global demands for radiology practice. While there are no major barriers for sharing such studies, when access is made from a (local) picture archive and communication system (PACS) within the domain of a healthcare organization, there are a number of impediments for sharing studies among health professionals on a global scale. Social radiology as an information infrastructure involves the notion of a shared infrastructure as a public good, affording a social space where people, organizations and technical components may spontaneously form associations in order to share clinical information linked to patient care and radiology practice. This article shows however, that such polarization establishes a tension between local and global demands, which hinders the emergence of social radiology as an information infrastructure. Based on an analysis of the social space for radiology practice, the present article has observed that this tension persists due to the inertia of a locally installed base in radiology departments, for which common teleradiology models are not truly capable of reorganizing as a global social space for radiology practice. Reconciling the local with the global signifies integrating PACS and teleradiology into an evolving, secure, heterogeneous, shared, open information infrastructure where the conceptual boundaries between (local) PACS and (global) teleradiology are transparent, signaling the emergence of social radiology as an information infrastructure. PMID:25600710

Enhancing Application Performance Using Mini-Apps: Comparison of Hybrid Parallel Programming Paradigms

NASA Technical Reports Server (NTRS)

Lawson, Gary; Poteat, Michael; Sosonkina, Masha; Baurle, Robert; Hammond, Dana

2016-01-01

In this work, several mini-apps have been created to enhance a real-world application performance, namely the VULCAN code for complex flow analysis developed at the NASA Langley Research Center. These mini-apps explore hybrid parallel programming paradigms with Message Passing Interface (MPI) for distributed memory access and either Shared MPI (SMPI) or OpenMP for shared memory accesses. Performance testing shows that MPI+SMPI yields the best execution performance, while requiring the largest number of code changes. A maximum speedup of 23X was measured for MPI+SMPI, but only 10X was measured for MPI+OpenMP.

Implementation and performance of parallel Prolog interpreter

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

Wei, S.; Kale, L.V.; Balkrishna, R.

1988-01-01

In this paper, the authors discuss the implementation of a parallel Prolog interpreter on different parallel machines. The implementation is based on the REDUCE--OR process model which exploits both AND and OR parallelism in logic programs. It is machine independent as it runs on top of the chare-kernel--a machine-independent parallel programming system. The authors also give the performance of the interpreter running a diverse set of benchmark pargrams on parallel machines including shared memory systems: an Alliant FX/8, Sequent and a MultiMax, and a non-shared memory systems: Intel iPSC/32 hypercube, in addition to its performance on a multiprocessor simulation system.

Parallel discrete event simulation using shared memory

NASA Technical Reports Server (NTRS)

Reed, Daniel A.; Malony, Allen D.; Mccredie, Bradley D.

1988-01-01

With traditional event-list techniques, evaluating a detailed discrete-event simulation-model can often require hours or even days of computation time. By eliminating the event list and maintaining only sufficient synchronization to ensure causality, parallel simulation can potentially provide speedups that are linear in the numbers of processors. A set of shared-memory experiments, using the Chandy-Misra distributed-simulation algorithm, to simulate networks of queues is presented. Parameters of the study include queueing network topology and routing probabilities, number of processors, and assignment of network nodes to processors. These experiments show that Chandy-Misra distributed simulation is a questionable alternative to sequential-simulation of most queueing network models.

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

Jones, J.P.; Bangs, A.L.; Butler, P.L.

Hetero Helix is a programming environment which simulates shared memory on a heterogeneous network of distributed-memory computers. The machines in the network may vary with respect to their native operating systems and internal representation of numbers. Hetero Helix presents a simple programming model to developers, and also considers the needs of designers, system integrators, and maintainers. The key software technology underlying Hetero Helix is the use of a compiler'' which analyzes the data structures in shared memory and automatically generates code which translates data representations from the format native to each machine into a common format, and vice versa. Themore » design of Hetero Helix was motivated in particular by the requirements of robotics applications. Hetero Helix has been used successfully in an integration effort involving 27 CPUs in a heterogeneous network and a body of software totaling roughly 100,00 lines of code. 25 refs., 6 figs.« less

Feature-based memory-driven attentional capture: visual working memory content affects visual attention.

PubMed

Olivers, Christian N L; Meijer, Frank; Theeuwes, Jan

2006-10-01

In 7 experiments, the authors explored whether visual attention (the ability to select relevant visual information) and visual working memory (the ability to retain relevant visual information) share the same content representations. The presence of singleton distractors interfered more strongly with a visual search task when it was accompanied by an additional memory task. Singleton distractors interfered even more when they were identical or related to the object held in memory, but only when it was difficult to verbalize the memory content. Furthermore, this content-specific interaction occurred for features that were relevant to the memory task but not for irrelevant features of the same object or for once-remembered objects that could be forgotten. Finally, memory-related distractors attracted more eye movements but did not result in longer fixations. The results demonstrate memory-driven attentional capture on the basis of content-specific representations. Copyright 2006 APA.

Self-defining memories, scripts, and the life story: narrative identity in personality and psychotherapy.

PubMed

Singer, Jefferson A; Blagov, Pavel; Berry, Meredith; Oost, Kathryn M

2013-12-01

An integrative model of narrative identity builds on a dual memory system that draws on episodic memory and a long-term self to generate autobiographical memories. Autobiographical memories related to critical goals in a lifetime period lead to life-story memories, which in turn become self-defining memories when linked to an individual's enduring concerns. Self-defining memories that share repetitive emotion-outcome sequences yield narrative scripts, abstracted templates that filter cognitive-affective processing. The life story is the individual's overarching narrative that provides unity and purpose over the life course. Healthy narrative identity combines memory specificity with adaptive meaning-making to achieve insight and well-being, as demonstrated through a literature review of personality and clinical research, as well as new findings from our own research program. A clinical case study drawing on this narrative identity model is also presented with implications for treatment and research. © 2012 Wiley Periodicals, Inc.

Working Memory in Children: A Time-Constrained Functioning Similar to Adults

ERIC Educational Resources Information Center

Portrat, Sophie; Camos, Valerie; Barrouillet, Pierre

2009-01-01

Within the time-based resource-sharing (TBRS) model, we tested a new conception of the relationships between processing and storage in which the core mechanisms of working memory (WM) are time constrained. However, our previous studies were restricted to adults. The current study aimed at demonstrating that these mechanisms are present and…

Close Associations and Memory in Brainwriting Groups

ERIC Educational Resources Information Center

Coskun, Hamit

2011-01-01

The present experiment examined whether or not the type of associations (close (e.g. apple-pear) and distant (e.g. apple-fish) word associations) and memory instruction (paying attention to the ideas of others) had effects on the idea generation performances in the brainwriting paradigm in which all participants shared their ideas by using paper…

Common data buffer

NASA Technical Reports Server (NTRS)

Byrne, F.

1981-01-01

Time-shared interface speeds data processing in distributed computer network. Two-level high-speed scanning approach routes information to buffer, portion of which is reserved for series of "first-in, first-out" memory stacks. Buffer address structure and memory are protected from noise or failed components by error correcting code. System is applicable to any computer or processing language.

Accumulating Evidence about What Prospective Memory Costs Actually Reveal

ERIC Educational Resources Information Center

Strickland, Luke; Heathcote, Andrew; Remington, Roger W.; Loft, Shayne

2017-01-01

Event-based prospective memory (PM) tasks require participants to substitute an atypical PM response for an ongoing task response when presented with PM targets. Responses to ongoing tasks are often slower with the addition of PM demands ("PM costs"). Prominent PM theories attribute costs to capacity-sharing between the ongoing and PM…

How communication goals determine when audience tuning biases memory.

PubMed

Echterhoff, Gerald; Higgins, E Tory; Kopietz, René; Groll, Stephan

2008-02-01

After tuning their message to suit their audience's attitude, communicators' own memories for the original information (e.g., a target person's behaviors) often reflect the biased view expressed in their message--producing an audience-congruent memory bias. Exploring the motivational circumstances of message production, the authors investigated whether this bias depends on the goals driving audience tuning. In 4 experiments, the memory bias was found to a greater extent when audience tuning served the creation of a shared reality than when it served alternative, nonshared reality goals (being polite toward a stigmatized-group audience; obtaining incentives; being entertaining; complying with a blatant demand). In addition, the authors found that these effects were mediated by the epistemic trust in the audience-congruent view but not by the rehearsal or accurate retrieval of the original input information, the ability to discriminate between the original and the message information, or a contrast away from extremely tuned messages. The central role of epistemic trust, a measure of the communicators' experience of shared reality, was supported in meta-analyses across the experiments. PsycINFO Database Record (c) 2008 APA, all rights reserved.

Next-generation acceleration and code optimization for light transport in turbid media using GPUs

PubMed Central

Alerstam, Erik; Lo, William Chun Yip; Han, Tianyi David; Rose, Jonathan; Andersson-Engels, Stefan; Lilge, Lothar

2010-01-01

A highly optimized Monte Carlo (MC) code package for simulating light transport is developed on the latest graphics processing unit (GPU) built for general-purpose computing from NVIDIA - the Fermi GPU. In biomedical optics, the MC method is the gold standard approach for simulating light transport in biological tissue, both due to its accuracy and its flexibility in modelling realistic, heterogeneous tissue geometry in 3-D. However, the widespread use of MC simulations in inverse problems, such as treatment planning for PDT, is limited by their long computation time. Despite its parallel nature, optimizing MC code on the GPU has been shown to be a challenge, particularly when the sharing of simulation result matrices among many parallel threads demands the frequent use of atomic instructions to access the slow GPU global memory. This paper proposes an optimization scheme that utilizes the fast shared memory to resolve the performance bottleneck caused by atomic access, and discusses numerous other optimization techniques needed to harness the full potential of the GPU. Using these techniques, a widely accepted MC code package in biophotonics, called MCML, was successfully accelerated on a Fermi GPU by approximately 600x compared to a state-of-the-art Intel Core i7 CPU. A skin model consisting of 7 layers was used as the standard simulation geometry. To demonstrate the possibility of GPU cluster computing, the same GPU code was executed on four GPUs, showing a linear improvement in performance with an increasing number of GPUs. The GPU-based MCML code package, named GPU-MCML, is compatible with a wide range of graphics cards and is released as an open-source software in two versions: an optimized version tuned for high performance and a simplified version for beginners (http://code.google.com/p/gpumcml). PMID:21258498

Fish Intake, Genetic Predisposition to Alzheimer Disease, and Decline in Global Cognition and Memory in 5 Cohorts of Older Persons.

PubMed

Samieri, Cécilia; Morris, Martha-Clare; Bennett, David A; Berr, Claudine; Amouyel, Philippe; Dartigues, Jean-François; Tzourio, Christophe; Chasman, Daniel I; Grodstein, Francine

2018-05-01

Fish are a primary source of long-chain omega-3 fatty acids, which may help delay cognitive aging. We pooled participants from the French Three-City study and 4 US cohorts (Nurses' Health Study, Women's Health Study, Chicago Health and Aging Project, and Rush Memory and Aging Project) for whom diet and cognitive data were available (n = 23,688 white persons, aged ≥65 years, 88% female, baseline year range of 1992-1999, and median follow-up range of 3.9-9.1 years) to investigate the relationship of fish intake to cognitive decline and examine interactions with genes related to Alzheimer disease. We estimated cohort-specific associations between fish and change in composite scores of global cognition and episodic memory using linear mixed models, and we pooled results using inverse-variance weighted meta-analysis. In multivariate analyses, higher fish intake was associated with slower decline in both global cognition and memory (P for trend ≤ 0.031). Consuming ≥4 servings/week versus <1 serving/week of fish was associated with a lower rate of memory decline: 0.018 (95% confidence interval: 0.004, 0.032) standard units, an effect estimate equivalent to that found for 4 years of age. For global cognition, no comparisons of higher versus low fish intake reached statistical significance. In this meta-analysis, higher fish intake was associated with a lower rate of memory decline. We found no evidence of effect modification by genes associated with Alzheimer disease.

Can We Remember Future Actions yet Forget the Last Two Minutes? Study in Transient Global Amnesia

ERIC Educational Resources Information Center

Hainselin, Mathieu; Quinette, Peggy; Desgranges, Beatrice; Martinaud, Olivier; Hannequin, Didier; de La Sayette, Vincent; Viader, Fausto; Eustache, Francis

2011-01-01

Transient global amnesia (TGA) is a clinical syndrome characterized by the abrupt onset of a massive episodic memory deficit that spares other cognitive functions. If the anterograde dimension is known to be impaired in TGA, researchers have yet to investigate prospective memory (PM)--which involves remembering to perform an intended action at…

Lessons Learned and Global Partnerships: Stories of Sexual and Reproductive Health from Namibia

ERIC Educational Resources Information Center

Maurer, Lis; Kelly, Maureen

2005-01-01

Through a Global Partnership Project, Planned Parenthood of the Southern Finger Lakes in Ithaca, New York and the Namibian Planned Parenthood Association (NAPPA) in Windhoek, Namibia have joined together to share best practices, technical assistance, support, and resources. The Global Partners share the common goal of increasing awareness,…

National Culture in Practice: Its Impact on Knowledge Sharing in Global Virtual Collaboration

ERIC Educational Resources Information Center

Wei, Kangning

2009-01-01

Issues concerning global virtual collaboration have received considerable attention in both the academic and practical world; however, little research has been conducted on knowledge-sharing activities in global virtual collaboration, which is a key process to achieve collaboration effectiveness. Due to national culture having been seen as one of…

Shared filtering processes link attentional and visual short-term memory capacity limits.

PubMed

Bettencourt, Katherine C; Michalka, Samantha W; Somers, David C

2011-09-30

Both visual attention and visual short-term memory (VSTM) have been shown to have capacity limits of 4 ± 1 objects, driving the hypothesis that they share a visual processing buffer. However, these capacity limitations also show strong individual differences, making the degree to which these capacities are related unclear. Moreover, other research has suggested a distinction between attention and VSTM buffers. To explore the degree to which capacity limitations reflect the use of a shared visual processing buffer, we compared individual subject's capacities on attentional and VSTM tasks completed in the same testing session. We used a multiple object tracking (MOT) and a VSTM change detection task, with varying levels of distractors, to measure capacity. Significant correlations in capacity were not observed between the MOT and VSTM tasks when distractor filtering demands differed between the tasks. Instead, significant correlations were seen when the tasks shared spatial filtering demands. Moreover, these filtering demands impacted capacity similarly in both attention and VSTM tasks. These observations fail to support the view that visual attention and VSTM capacity limits result from a shared buffer but instead highlight the role of the resource demands of underlying processes in limiting capacity.

A class Hierarchical, object-oriented approach to virtual memory management

NASA Technical Reports Server (NTRS)

Russo, Vincent F.; Campbell, Roy H.; Johnston, Gary M.

1989-01-01

The Choices family of operating systems exploits class hierarchies and object-oriented programming to facilitate the construction of customized operating systems for shared memory and networked multiprocessors. The software is being used in the Tapestry laboratory to study the performance of algorithms, mechanisms, and policies for parallel systems. Described here are the architectural design and class hierarchy of the Choices virtual memory management system. The software and hardware mechanisms and policies of a virtual memory system implement a memory hierarchy that exploits the trade-off between response times and storage capacities. In Choices, the notion of a memory hierarchy is captured by abstract classes. Concrete subclasses of those abstractions implement a virtual address space, segmentation, paging, physical memory management, secondary storage, and remote (that is, networked) storage. Captured in the notion of a memory hierarchy are classes that represent memory objects. These classes provide a storage mechanism that contains encapsulated data and have methods to read or write the memory object. Each of these classes provides specializations to represent the memory hierarchy.

Huperzine A attenuates cognitive deficits and hippocampal neuronal damage after transient global ischemia in gerbils.

PubMed

Zhou, J; Zhang, H Y; Tang, X C

2001-11-09

The protective effects of huperzine A on transient global ischemia in gerbils were investigated. Five min of global ischemia in gerbils results in working memory impairments shown by increased escape latency in a water maze and reduced time spent in the target quadrant. These signs of dysfunction are accompanied by delayed degeneration of pyramidal hippocampal CA1 neurons and by decrease in acetylcholinesterase activity in the hippocampus. Subchronic oral administration of huperzine A (0.1 mg/kg, twice per day for 14 days) after ischemia significantly reduced the memory impairment, reduced neuronal degeneration in the CA1 region, and partially restored hippocampal choline acetyltransferase activity. The ability of huperzine A to attenuate memory deficits and neuronal damage after ischemia might be beneficial in cerebrovascular type dementia.

Genetic and environmental contributions to the associations between intraindividual variability in reaction time and cognitive function.

PubMed

Finkel, Deborah; Pedersen, Nancy L

2014-01-01

Intraindividual variability (IIV) in reaction time has been related to cognitive decline, but questions remain about the nature of this relationship. Mean and range in movement and decision time for simple reaction time were available from 241 individuals aged 51-86 years at the fifth testing wave of the Swedish Adoption/Twin Study of Aging. Cognitive performance on four factors was also available: verbal, spatial, memory, and speed. Analyses indicated that range in reaction time could be used as an indicator of IIV. Heritability estimates were 35% for mean reaction and 20% for range in reaction. Multivariate analysis indicated that the genetic variance on the memory, speed, and spatial factors is shared with genetic variance for mean or range in reaction time. IIV shares significant genetic variance with fluid ability in late adulthood, over and above and genetic variance shared with mean reaction time.

A Study of Shared-Memory Mutual Exclusion Protocols Using CADP

NASA Astrophysics Data System (ADS)

Mateescu, Radu; Serwe, Wendelin

Mutual exclusion protocols are an essential building block of concurrent systems: indeed, such a protocol is required whenever a shared resource has to be protected against concurrent non-atomic accesses. Hence, many variants of mutual exclusion protocols exist in the shared-memory setting, such as Peterson's or Dekker's well-known protocols. Although the functional correctness of these protocols has been studied extensively, relatively little attention has been paid to their non-functional aspects, such as their performance in the long run. In this paper, we report on experiments with the performance evaluation of mutual exclusion protocols using Interactive Markov Chains. Steady-state analysis provides an additional criterion for comparing protocols, which complements the verification of their functional properties. We also carefully re-examined the functional properties, whose accurate formulation as temporal logic formulas in the action-based setting turns out to be quite involved.

Handling debugger breakpoints in a shared instruction system

DOEpatents

Gooding, Thomas Michael; Shok, Richard Michael

2014-01-21

A debugger debugs processes that execute shared instructions so that a breakpoint set for one process will not cause a breakpoint to occur in the other processes. A breakpoint is set by recording the original instruction at the desired location and writing a trap instruction to the shared instructions at that location. When a process encounters the breakpoint, the process passes control to the debugger for breakpoint processing if the breakpoint was set at that location for that process. If the trap was not set at that location for that process, the cacheline containing the trap is copied to a small scratchpad memory, and the virtual memory mappings are changed to translate the virtual address of the cacheline to the scratchpad. The original instruction is then written to replace the trap instruction in the scratchpad, so that process can execute the instructions in the scatchpad thereby avoiding the trap instruction.

An Army dentist in the combat zone during WWII.

PubMed

Orden, C Q

2001-11-01

It is 60 years since the bombing of Pearl Harbor and the outbreak of World War II for the United States. Some of the men and women who served in the armed forces at the time are willing to share some of their reminiscences with those of us who could not serve for one reason or another or who may not even have been born at the time. One of the dentists who is willing to share some of his memories is Dr. Charles Q. Orden of New York. Unless these people share their memories much history will be lost forever in the next years, and we will all be poorer for it. We sincerely thank Dr. Orden for his offer of information and for allowing us to reproduce Fig. 1 in which he is seen as the dentist using a field dental chair, a foot-powered drill, and with a black dental corpsman as his assistant.

Semantic acquisition without memories: evidence from transient global amnesia.

PubMed

Guillery, B; Desgranges, B; Katis, S; de la Sayette, V; Viader, F; Eustache, F

2001-12-04

Transient global amnesia (TGA), characterised by a profound anterograde amnesia, is a model of interest to study the acquisition of novel meanings independent of episodic functioning. Three patients were tested during a TGA attack, two in the early recovery phase and the third during the acute phase of TGA, with a semantic priming task involving a restructuring process of conceptual knowledge. During TGA, all patients demonstrated priming effects. Results obtained the day after the episode with the same task showed that these effects persisted at least one day. Episodic memory seems not to be critical for the formation of novel connections among unrelated semantic representations, in accordance with Tulving's model of memory, i.e. episodic memory is not necessary for the acquisition of semantic information.

Memory Systems Do Not Divide on Consciousness: Reinterpreting Memory in Terms of Activation and Binding

PubMed Central

Reder, Lynne M.; Park, Heekyeong; Kieffaber, Paul D.

2009-01-01

There is a popular hypothesis that performance on implicit and explicit memory tasks reflects 2 distinct memory systems. Explicit memory is said to store those experiences that can be consciously recollected, and implicit memory is said to store experiences and affect subsequent behavior but to be unavailable to conscious awareness. Although this division based on awareness is a useful taxonomy for memory tasks, the authors review the evidence that the unconscious character of implicit memory does not necessitate that it be treated as a separate system of human memory. They also argue that some implicit and explicit memory tasks share the same memory representations and that the important distinction is whether the task (implicit or explicit) requires the formation of a new association. The authors review and critique dissociations from the behavioral, amnesia, and neuroimaging literatures that have been advanced in support of separate explicit and implicit memory systems by highlighting contradictory evidence and by illustrating how the data can be accounted for using a simple computational memory model that assumes the same memory representation for those disparate tasks. PMID:19210052

Visual working memory modulates low-level saccade target selection: Evidence from rapidly generated saccades in the global effect paradigm

PubMed Central

Hollingworth, Andrew; Matsukura, Michi; Luck, Steven J.

2013-01-01

In three experiments, we examined the influence of visual working memory (VWM) on the metrics of saccade landing position in a global effect paradigm. Participants executed a saccade to the more eccentric object in an object pair appearing on the horizontal midline, to the left or right of central fixation. While completing the saccade task, participants maintained a color in VWM for an unrelated memory task. Either the color of the saccade target matched the memory color (target match), the color of the distractor matched the memory color (distractor match), or the colors of neither object matched the memory color (no match). In the no-match condition, saccades tended to land at the midpoint between the two objects: the global, or averaging, effect. However, when one of the two objects matched VWM, the distribution of landing position shifted toward the matching object, both for target match and for distractor match. VWM modulation of landing position was observed even for the fastest quartile of saccades, with a mean latency as low as 112 ms. Effects of VWM on such rapidly generated saccades, with latencies in the express-saccade range, indicate that VWM interacts with the initial sweep of visual sensory processing, modulating perceptual input to oculomotor systems and thereby biasing oculomotor selection. As a result, differences in memory match produce effects on landing position similar to the effects generated by differences in physical salience. PMID:24190909

A New Local Bipolar Autoassociative Memory Based on External Inputs of Discrete Recurrent Neural Networks With Time Delay.

PubMed

Zhou, Caigen; Zeng, Xiaoqin; Luo, Chaomin; Zhang, Huaguang

In this paper, local bipolar auto-associative memories are presented based on discrete recurrent neural networks with a class of gain type activation function. The weight parameters of neural networks are acquired by a set of inequalities without the learning procedure. The global exponential stability criteria are established to ensure the accuracy of the restored patterns by considering time delays and external inputs. The proposed methodology is capable of effectively overcoming spurious memory patterns and achieving memory capacity. The effectiveness, robustness, and fault-tolerant capability are validated by simulated experiments.In this paper, local bipolar auto-associative memories are presented based on discrete recurrent neural networks with a class of gain type activation function. The weight parameters of neural networks are acquired by a set of inequalities without the learning procedure. The global exponential stability criteria are established to ensure the accuracy of the restored patterns by considering time delays and external inputs. The proposed methodology is capable of effectively overcoming spurious memory patterns and achieving memory capacity. The effectiveness, robustness, and fault-tolerant capability are validated by simulated experiments.

Distinct and shared cognitive functions mediate event- and time-based prospective memory impairment in normal ageing

PubMed Central

Gonneaud, Julie; Kalpouzos, Grégoria; Bon, Laetitia; Viader, Fausto; Eustache, Francis; Desgranges, Béatrice

2011-01-01

Prospective memory (PM) is the ability to remember to perform an action at a specific point in the future. Regarded as multidimensional, PM involves several cognitive functions that are known to be impaired in normal aging. In the present study, we set out to investigate the cognitive correlates of PM impairment in normal aging. Manipulating cognitive load, we assessed event- and time-based PM, as well as several cognitive functions, including executive functions, working memory and retrospective episodic memory, in healthy subjects covering the entire adulthood. We found that normal aging was characterized by PM decline in all conditions and that event-based PM was more sensitive to the effects of aging than time-based PM. Whatever the conditions, PM was linked to inhibition and processing speed. However, while event-based PM was mainly mediated by binding and retrospective memory processes, time-based PM was mainly related to inhibition. The only distinction between high- and low-load PM cognitive correlates lays in an additional, but marginal, correlation between updating and the high-load PM condition. The association of distinct cognitive functions, as well as shared mechanisms with event- and time-based PM confirms that each type of PM relies on a different set of processes. PMID:21678154

Neuropsychological characteristics of child and adolescent offspring of patients with schizophrenia or bipolar disorder.

PubMed

de la Serna, Elena; Sugranyes, Gisela; Sanchez-Gistau, Vanessa; Rodriguez-Toscano, Elisa; Baeza, Immaculada; Vila, Montserrat; Romero, Soledad; Sanchez-Gutierrez, Teresa; Penzol, Mª José; Moreno, Dolores; Castro-Fornieles, Josefina

2017-05-01

Schizophrenia (SZ) and bipolar disorder (BD) are considered neurobiological disorders which share some clinical, cognitive and neuroimaging characteristics. Studying child and adolescent offspring of patients diagnosed with bipolar disorder (BDoff) or schizophrenia (SZoff) is regarded as a reliable method for investigating early alterations and vulnerability factors for these disorders. This study compares the neuropsychological characteristics of SZoff, BDoff and a community control offspring group (CC) with the aim of examining shared and differential cognitive characteristics among groups. 41 SZoff, 90 BDoff and 107 CC were recruited. They were all assessed with a complete neuropsychological battery which included intelligence quotient, working memory (WM), processing speed, verbal memory and learning, visual memory, executive functions and sustained attention. SZoff and BDoff showed worse performance in some cognitive areas compared with CC. Some of these difficulties (visual memory) were common to both offspring groups, whereas others, such as verbal learning and WM in SZoff or PSI in BDoff, were group-specific. The cognitive difficulties in visual memory shown by both the SZoff and BDoff groups might point to a common endophenotype in the two disorders. Difficulties in other cognitive functions would be specific depending on the family diagnosis. Copyright © 2016 Elsevier B.V. All rights reserved.

Working memory costs of task switching.

PubMed

Liefooghe, Baptist; Barrouillet, Pierre; Vandierendonck, André; Camos, Valérie

2008-05-01

Although many accounts of task switching emphasize the importance of working memory as a substantial source of the switch cost, there is a lack of evidence demonstrating that task switching actually places additional demands on working memory. The present study addressed this issue by implementing task switching in continuous complex span tasks with strictly controlled time parameters. A series of 4 experiments demonstrate that recall performance decreased as a function of the number of task switches and that the concurrent load of item maintenance had no influence on task switching. These results indicate that task switching induces a cost on working memory functioning. Implications for theories of task switching, working memory, and resource sharing are addressed.

Generation-based memory synchronization in a multiprocessor system with weakly consistent memory accesses

DOEpatents

Ohmacht, Martin

2017-08-15

In a multiprocessor system, a central memory synchronization module coordinates memory synchronization requests responsive to memory access requests in flight, a generation counter, and a reclaim pointer. The central module communicates via point-to-point communication. The module includes a global OR reduce tree for each memory access requesting device, for detecting memory access requests in flight. An interface unit is implemented associated with each processor requesting synchronization. The interface unit includes multiple generation completion detectors. The generation count and reclaim pointer do not pass one another.

Generation-based memory synchronization in a multiprocessor system with weakly consistent memory accesses

DOEpatents

Ohmacht, Martin

2014-09-09

In a multiprocessor system, a central memory synchronization module coordinates memory synchronization requests responsive to memory access requests in flight, a generation counter, and a reclaim pointer. The central module communicates via point-to-point communication. The module includes a global OR reduce tree for each memory access requesting device, for detecting memory access requests in flight. An interface unit is implemented associated with each processor requesting synchronization. The interface unit includes multiple generation completion detectors. The generation count and reclaim pointer do not pass one another.

Viewing benefit sharing in global health research through the lens of Aristotelian justice.

PubMed

Dauda, Bege; Dierickx, Kris

2017-06-01

The ethics of benefit sharing has been a topical issue in global health research in resource-limited countries. It pertains to the distribution of goods, benefits and advantages to the research participants, communities and countries that are involved in research. One of the nuances in benefit sharing is the ethical justification on which the concept should be based. Extensive literature outlining the different principles underlying benefit sharing is available. The purpose of this paper is to examine the proposed principles using Aristotelian principles of justice. The paper assesses the central idea of Aristotelian justice and applies and evaluates this idea to benefit sharing in research, especially when commercial research sponsors conduct research in resource-limited countries. Two categories of Aristotelian justice-universal and particular-were examined and their contribution to the benefit-sharing discourse assessed. On the one hand, benefit sharing in accordance with universal justice requires that for-profit research sponsors obey the legal regulations and international standards set for benefit sharing. On the other hand, benefit sharing in accordance with particular justice transcends obeying legal requirements and standards to a realm of acting in an ethically accepted manner. Accordingly, the paper further examines three perspectives of particular justice and develops ethical justification for benefit sharing in global health research. As Aristotelian justice is still relevant to the contemporary discourse on justice, this paper broadens the ethical justifications of benefit sharing in global health research. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

78 FR 67427 - Self-Regulatory Organizations; NYSE Arca, Inc.; Notice of Filing and Immediate Effectiveness of...

Federal Register 2010, 2011, 2012, 2013, 2014

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... Change Proposing to Amend the Rule Governing the Listing and Trading of Shares of the WisdomTree Global... change to the means of achieving the investment objective applicable to the WisdomTree Global Real Return... Rule 8.600 \\4\\ (``Managed Fund Shares'').\\5\\ The Shares are offered by the WisdomTree Trust (``Trust...

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... Relating to the Listing and Trading of Shares of the WisdomTree Global Corporate Bond Fund of the WisdomTree Trust October 19, 2012. I. Introduction On August 15, 2012, The NASDAQ Stock Market LLC (``Nasdaq... proposed rule change to list and trade the shares (``Shares'') of the WisdomTree Global Corporate Bond Fund...

Method of up-front load balancing for local memory parallel processors

NASA Technical Reports Server (NTRS)

Baffes, Paul Thomas (Inventor)

1990-01-01

In a parallel processing computer system with multiple processing units and shared memory, a method is disclosed for uniformly balancing the aggregate computational load in, and utilizing minimal memory by, a network having identical computations to be executed at each connection therein. Read-only and read-write memory are subdivided into a plurality of process sets, which function like artificial processing units. Said plurality of process sets is iteratively merged and reduced to the number of processing units without exceeding the balance load. Said merger is based upon the value of a partition threshold, which is a measure of the memory utilization. The turnaround time and memory savings of the instant method are functions of the number of processing units available and the number of partitions into which the memory is subdivided. Typical results of the preferred embodiment yielded memory savings of from sixty to seventy five percent.

Hippocampal and ventral medial prefrontal activation during retrieval-mediated learning supports novel inference.

PubMed

Zeithamova, Dagmar; Dominick, April L; Preston, Alison R

2012-07-12

Memory enables flexible use of past experience to inform new behaviors. Although leading theories hypothesize that this fundamental flexibility results from the formation of integrated memory networks relating multiple experiences, the neural mechanisms that support memory integration are not well understood. Here, we demonstrate that retrieval-mediated learning, whereby prior event details are reinstated during encoding of related experiences, supports participants' ability to infer relationships between distinct events that share content. Furthermore, we show that activation changes in a functionally coupled hippocampal and ventral medial prefrontal cortical circuit track the formation of integrated memories and successful inferential memory performance. These findings characterize the respective roles of these regions in retrieval-mediated learning processes that support relational memory network formation and inferential memory in the human brain. More broadly, these data reveal fundamental mechanisms through which memory representations are constructed into prospectively useful formats. Copyright © 2012 Elsevier Inc. All rights reserved.

Hippocampal and ventral medial prefrontal activation during retrieval-mediated learning supports novel inference

PubMed Central

Zeithamova, Dagmar; Dominick, April L.; Preston, Alison R.

2012-01-01

SUMMARY Memory enables flexible use of past experience to inform new behaviors. Though leading theories hypothesize that this fundamental flexibility results from the formation of integrated memory networks relating multiple experiences, the neural mechanisms that support memory integration are not well understood. Here, we demonstrate that retrieval-mediated learning, whereby prior event details are reinstated during encoding of related experiences, supports participants’ ability to infer relationships between distinct events that share content. Furthermore, we show that activation changes in a functionally coupled hippocampal and ventral medial prefrontal cortical circuit track the formation of integrated memories and successful inferential memory performance. These findings characterize the respective roles of these regions in retrieval-mediated learning processes that support relational memory network formation and inferential memory in the human brain. More broadly, these data reveal fundamental mechanisms through which memory representations are constructed into prospectively useful formats. PMID:22794270

Jim Thomas: A Collection of Memories

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

Wong, Pak C.

Jim Thomas, a guest editor and a long-time associate editor of Information Visualization (IVS), died in Richland, WA, on August 6, 2010 due to complications from a brain tumor. His friends and colleagues from around the world have since expressed their sadness and paid tribute to a visionary scientist in multiple public forums. For those who didn't get the chance to know Jim, I share a collection of my own memories of Jim Thomas and memories from some of his colleagues.

77 FR 9281 - Self-Regulatory Organizations; NYSE Arca, Inc.; Notice of Filing of Proposed Rule Change Relating...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-16

... and Trading of the PIMCO Global Advantage Inflation-Linked Bond Strategy Fund Under NYSE Arca Equities...''): PIMCO Global Advantage Inflation-Linked Bond Strategy Fund. The text of the proposed rule change is... Shares \\3\\ (``Shares'') under NYSE Arca Equities Rule 8.600: PIMCO Global Advantage Inflation-Linked Bond...

Constructing Patriotism: Teaching History and Memories in Global Worlds. Advances in Cultural Psychology: Constructing Human Development

ERIC Educational Resources Information Center

Carretero, Mario

2011-01-01

Memory construction and national identity are key issues in our societies, as well as it is patriotism. How can we nowadays believe and give sense to traditional narrations that explain the origins of nations and communities? How do these narrations function in a process of globalization? How should we remember the recent past? In the construction…

The effect of bupropion XL and escitalopram on memory and functional outcomes in adults with major depressive disorder: results from a randomized controlled trial.

PubMed

Soczynska, Joanna K; Ravindran, Lakshmi N; Styra, Rima; McIntyre, Roger S; Cyriac, Anna; Manierka, Marena S; Kennedy, Sidney H

2014-12-15

Decrements in cognitive function are a common feature of Major Depressive Disorder (MDD), and whether distinct classes of antidepressants differentially affect memory in these individuals has not been sufficiently evaluated. In this study we sought to determine the effect of escitalopram and bupropion XL on memory and psychosocial function. Forty-one individuals (18-50 years) with MDD were enrolled in an 8-week, double-blind, double-dummy, randomized controlled comparative trial of bupropion XL and escitalopram. Thirty-six participants completed pre and post memory assessments. Verbal, non-verbal and working memory were evaluated with a comprehensive neuropsychological battery. Psychosocial function was assessed with the Sheehan Disability Scale and Endicott Work Productivity Scale. Escitalopram and bupropion XL significantly improved immediate as well as delayed verbal and nonverbal memory, global function (all p≤0.001), and work productivity (p=0.045), with no significant between-group differences. Improvement in immediate verbal memory exerted a direct influence on improvement in global function (p=0.006). Treatment with either escitalopram or bupropion XL was associated with improvement in memory and psychosocial function in adults with MDD. Copyright © 2014. Published by Elsevier Ireland Ltd.

Effects of motor congruence on visual working memory.

PubMed

Quak, Michel; Pecher, Diane; Zeelenberg, Rene

2014-10-01

Grounded-cognition theories suggest that memory shares processing resources with perception and action. The motor system could be used to help memorize visual objects. In two experiments, we tested the hypothesis that people use motor affordances to maintain object representations in working memory. Participants performed a working memory task on photographs of manipulable and nonmanipulable objects. The manipulable objects were objects that required either a precision grip (i.e., small items) or a power grip (i.e., large items) to use. A concurrent motor task that could be congruent or incongruent with the manipulable objects caused no difference in working memory performance relative to nonmanipulable objects. Moreover, the precision- or power-grip motor task did not affect memory performance on small and large items differently. These findings suggest that the motor system plays no part in visual working memory.

Many Roads Lead to Recognition: Electrophysiological Correlates of Familiarity Derived from Short-Term Masked Repetition Priming

ERIC Educational Resources Information Center

Lucas, Heather D.; Taylor, Jason R.; Henson, Richard N.; Paller, Ken A.

2012-01-01

The neural mechanisms that underlie familiarity memory have been extensively investigated, but a consensus understanding remains elusive. Behavioral evidence suggests that familiarity sometimes shares sources with instances of implicit memory known as priming, in that the same increases in processing fluency that give rise to priming can engender…

Forward Association, Backward Association, and the False-Memory Illusion

ERIC Educational Resources Information Center

Brainerd, C. J.; Wright, Ron

2005-01-01

In the Deese-Roediger-McDermott false-memory illusion, forward associative strength (FAS) is unrelated to the strength of the illusion; this is puzzling, because high-FAS lists ought to share more semantic features with critical unpresented words than should low-FAS lists. The authors show that this null result is probably a truncated range…

The Impact of Storage on Processing: How Is Information Maintained in Working Memory?

ERIC Educational Resources Information Center

Vergauwe, Evie; Camos, Valérie; Barrouillet, Pierre

2014-01-01

Working memory is typically defined as a system devoted to the simultaneous maintenance and processing of information. However, the interplay between these 2 functions is still a matter of debate in the literature, with views ranging from complete independence to complete dependence. The time-based resource-sharing model assumes that a central…

Selecting Learning Tasks: Effects of Adaptation and Shared Control on Learning Efficiency and Task Involvement

ERIC Educational Resources Information Center

Corbalan, Gemma; Kester, Liesbeth; van Merrienboer, Jeroen J. G.

2008-01-01

Complex skill acquisition by performing authentic learning tasks is constrained by limited working memory capacity [Baddeley, A. D. (1992). Working memory. "Science, 255", 556-559]. To prevent cognitive overload, task difficulty and support of each newly selected learning task can be adapted to the learner's competence level and perceived task…

Android Protection Mechanism: A Signed Code Security Mechanism for Smartphone Applications

DTIC Science & Technology

2011-03-01

status registers, exceptions, endian support, unaligned access support, synchronization primitives , the Jazelle Extension, and saturated integer...supports comprehensive non-blocking shared-memory synchronization primitives that scale for multiple-processor system designs. This is an improvement... synchronization . Memory semaphores can be loaded and altered without interruption because the load and store operations are atomic. Processor

Senior Citizens' Personal Stories...Literacy through Narrative...Sharing the Richness of the Past.

ERIC Educational Resources Information Center

Lineberry, Colleen

Using simple writing strategies, senior citizens at an elder camp workshop collected memories in journals. In some cases, readings were used to trigger memories. The exercise enabled students to make connections between their own life experiences and the life experiences of others. Workshops encouraging participants to tell their own stories for…

Processes and Content of Narrative Identity Development in Adolescence: Gender and Well-Being

ERIC Educational Resources Information Center

McLean, Kate C.; Breen, Andrea V.

2009-01-01

The present study examined narrative identity in adolescence (14-18 years) in terms of narrative content and processes of identity development. Age- and gender-related differences in narrative patterns in turning point memories and gender differences in the content and functions for sharing those memories were examined, as was the relationship…

The Performance of a Lifetime

ERIC Educational Resources Information Center

Burdette, Kimberly

2007-01-01

In this article, the author recalls and shares the first half of her college journey. Her memories do not play back to her in bursts of sounds or colors; friends or lovers; feelings, touches, tastes, or ideas. They play, rather, as silent images of herself that flicker disjointedly across her mind, the lens of her memory having recorded her…

Schools of the Past: A Treasury of Photographs. Fastback 80.

ERIC Educational Resources Information Center

Davis, O. L., Jr.

The experience of schooling in America is recalled through a memory-sharing essay and an album of photographs. The intent of the article is to prompt readers to remember their personal schooling experiences and relate them to the larger framework of national memories. The essay, focusing on schools at the turn of the 20th century, discusses…

Shared Etiology of Phonological Memory and Vocabulary Deficits in School-Age Children

ERIC Educational Resources Information Center

Peterson, Robin L.; Pennington, Bruce F.; Samuelsson, Stefan; Byrne, Brian; Olson, Richard K.

2013-01-01

Purpose: The goal of this study was to investigate the etiologic basis for the association between deficits in phonological memory (PM) and vocabulary in school-age children. Method: Children with deficits in PM or vocabulary were identified within the International Longitudinal Twin Study (ILTS; Samuelsson et al., 2005). The ILTS includes 1,045…

The CA3 Network as a Memory Store for Spatial Representations

ERIC Educational Resources Information Center

Papp, Gergely; Witter, Menno P.; Treves, Alessandro

2007-01-01

Comparative neuroanatomy suggests that the CA3 region of the mammalian hippocampus is directly homologous with the medio-dorsal pallium in birds and reptiles, with which it largely shares the basic organization of primitive cortex. Autoassociative memory models, which are generically applicable to cortical networks, then help assess how well CA3…

Memories Are Made of This

ERIC Educational Resources Information Center

Chang, Christine

2010-01-01

In this article, the author shares her memories of Sally Smith, the founder of The Lab School of Washington, where she works as the director of the Occupational Therapy. When the author first met Smith, Smith asked her what brought her to The Lab School at that point in her career. She told Smith that her background was rather eclectic, since she…

They're Why We're Here

ERIC Educational Resources Information Center

Razook, Nim

2009-01-01

The author began teaching at the University of Oklahoma in the late 1970s. In this article, the author shares two memories of those times on campus. The first was looking out his office window and seeing Iranian students marching on campus, shouting, "The Shah is a Fascist Pig." The second memory provoked this paper. It made the author…

Rearview Memories

ERIC Educational Resources Information Center

Gross, Gwen E.

2008-01-01

In this article, the author shares her experience when she was still a student until she became a superintendent. In her 17th year in the superintendency, the author finds the joys of her work all around her, grateful to be bestowed with the gift of leadership. She shares with colleagues a few especially meaningful moments from her professional…

Shared and Unique Genetic and Environmental Influences on Aging-Related Changes in Multiple Cognitive Abilities

PubMed Central

Tucker-Drob, Elliot M.; Reynolds, Chandra A.; Finkel, Deborah; Pedersen, Nancy L.

2013-01-01

Aging-related declines occur in many different domains of cognitive function during later adulthood. However, whether a global dimension underlies individual differences in changes in different domains of cognition, and whether global genetic influences on cognitive changes exist, is less clear. We addressed these issues by applying multivariate growth curve models to longitudinal data from 857 individuals from the Swedish Adoption/Twin Study of Aging, who had been measured on 11 cognitive variables representative of verbal, spatial, memory, and processing speed abilities up to 5 times over up to 16 years between ages 50 and 96 years. Between ages 50 and 65 years scores on different tests changed relatively independently of one another, and there was little evidence for strong underlying dimensions of change. In contrast, over the period between 65 and 96 years of age, there were strong interrelations among rates of change both within and across domains. During this age period, variability in rates of change were, on average, 52% domain-general, 8% domain-specific, and 39% test specific. Quantitative genetic decomposition indicated that 29% of individual differences in a global domain-general dimension of cognitive changes from 65 to 96 years were attributable to genetic influences, but some domain-specific genetic influences were also evident, even after accounting for domain-general contributions. These findings are consistent with a balanced global and domain-specific account of the genetics of cognitive aging. PMID:23586942

Shared and unique genetic and environmental influences on aging-related changes in multiple cognitive abilities.

PubMed

Tucker-Drob, Elliot M; Reynolds, Chandra A; Finkel, Deborah; Pedersen, Nancy L

2014-01-01

Aging-related declines occur in many different domains of cognitive function during middle and late adulthood. However, whether a global dimension underlies individual differences in changes in different domains of cognition and whether global genetic influences on cognitive changes exist is less clear. We addressed these issues by applying multivariate growth curve models to longitudinal data from 857 individuals from the Swedish Adoption/Twin Study of Aging, who had been measured on 11 cognitive variables representative of verbal, spatial, memory, and processing speed abilities up to 5 times over up to 16 years between ages 50 and 96 years. Between ages 50 and 65 years scores on different tests changed relatively independently of one another, and there was little evidence for strong underlying dimensions of change. In contrast, over the period between 65 and 96 years of age, there were strong interrelations among rates of change both within and across domains. During this age period, variability in rates of change were, on average, 52% domain-general, 8% domain-specific, and 39% test-specific. Quantitative genetic decomposition indicated that 29% of individual differences in a global domain-general dimension of cognitive changes during this age period were attributable to genetic influences, but some domain-specific genetic influences were also evident, even after accounting for domain-general contributions. These findings are consistent with a balanced global and domain-specific account of the genetics of cognitive aging. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Ageing-related stereotypes in memory: When the beliefs come true.

PubMed

Bouazzaoui, Badiâa; Follenfant, Alice; Ric, François; Fay, Séverine; Croizet, Jean-Claude; Atzeni, Thierry; Taconnat, Laurence

2016-01-01

Age-related stereotype concerns culturally shared beliefs about the inevitable decline of memory with age. In this study, stereotype priming and stereotype threat manipulations were used to explore the impact of age-related stereotype on metamemory beliefs and episodic memory performance. Ninety-two older participants who reported the same perceived memory functioning were divided into two groups: a threatened group and a non-threatened group (control). First, the threatened group was primed with an ageing stereotype questionnaire. Then, both groups were administered memory complaints and memory self-efficacy questionnaires to measure metamemory beliefs. Finally, both groups were administered the Logical Memory task to measure episodic memory, for the threatened group the instructions were manipulated to enhance the stereotype threat. Results indicated that the threatened individuals reported more memory complaints and less memory efficacy, and had lower scores than the control group on the logical memory task. A multiple mediation analysis revealed that the stereotype threat effect on the episodic memory performance was mediated by both memory complaints and memory self-efficacy. This study revealed that stereotype threat impacts belief in one's own memory functioning, which in turn impairs episodic memory performance.

Efficient ICCG on a shared memory multiprocessor

NASA Technical Reports Server (NTRS)

Hammond, Steven W.; Schreiber, Robert

1989-01-01

Different approaches are discussed for exploiting parallelism in the ICCG (Incomplete Cholesky Conjugate Gradient) method for solving large sparse symmetric positive definite systems of equations on a shared memory parallel computer. Techniques for efficiently solving triangular systems and computing sparse matrix-vector products are explored. Three methods for scheduling the tasks in solving triangular systems are implemented on the Sequent Balance 21000. Sample problems that are representative of a large class of problems solved using iterative methods are used. We show that a static analysis to determine data dependences in the triangular solve can greatly improve its parallel efficiency. We also show that ignoring symmetry and storing the whole matrix can reduce solution time substantially.

MPF: A portable message passing facility for shared memory multiprocessors

NASA Technical Reports Server (NTRS)

Malony, Allen D.; Reed, Daniel A.; Mcguire, Patrick J.

1987-01-01

The design, implementation, and performance evaluation of a message passing facility (MPF) for shared memory multiprocessors are presented. The MPF is based on a message passing model conceptually similar to conversations. Participants (parallel processors) can enter or leave a conversation at any time. The message passing primitives for this model are implemented as a portable library of C function calls. The MPF is currently operational on a Sequent Balance 21000, and several parallel applications were developed and tested. Several simple benchmark programs are presented to establish interprocess communication performance for common patterns of interprocess communication. Finally, performance figures are presented for two parallel applications, linear systems solution, and iterative solution of partial differential equations.

Which neuropsychological functions predict various processing speed components in children with and without attention-deficit/hyperactivity disorder?

PubMed

Vadnais, Sarah A; Kibby, Michelle Y; Jagger-Rickels, Audreyana C

2018-01-01

We identified statistical predictors of four processing speed (PS) components in a sample of 151 children with and without attention-deficit/hyperactivity disorder (ADHD). Performance on perceptual speed was predicted by visual attention/short-term memory, whereas incidental learning/psychomotor speed was predicted by verbal working memory. Rapid naming was predictive of each PS component assessed, and inhibition predicted all but one task, suggesting a shared need to identify/retrieve stimuli rapidly and inhibit incorrect responding across PS components. Hence, we found both shared and unique predictors of perceptual, cognitive, and output speed, suggesting more specific terminology should be used in future research on PS in ADHD.

Parallel k-means++ for Multiple Shared-Memory Architectures

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

Mackey, Patrick S.; Lewis, Robert R.

2016-09-22

In recent years k-means++ has become a popular initialization technique for improved k-means clustering. To date, most of the work done to improve its performance has involved parallelizing algorithms that are only approximations of k-means++. In this paper we present a parallelization of the exact k-means++ algorithm, with a proof of its correctness. We develop implementations for three distinct shared-memory architectures: multicore CPU, high performance GPU, and the massively multithreaded Cray XMT platform. We demonstrate the scalability of the algorithm on each platform. In addition we present a visual approach for showing which platform performed k-means++ the fastest for varyingmore » data sizes.« less

A multiarchitecture parallel-processing development environment

NASA Technical Reports Server (NTRS)

Townsend, Scott; Blech, Richard; Cole, Gary

1993-01-01

A description is given of the hardware and software of a multiprocessor test bed - the second generation Hypercluster system. The Hypercluster architecture consists of a standard hypercube distributed-memory topology, with multiprocessor shared-memory nodes. By using standard, off-the-shelf hardware, the system can be upgraded to use rapidly improving computer technology. The Hypercluster's multiarchitecture nature makes it suitable for researching parallel algorithms in computational field simulation applications (e.g., computational fluid dynamics). The dedicated test-bed environment of the Hypercluster and its custom-built software allows experiments with various parallel-processing concepts such as message passing algorithms, debugging tools, and computational 'steering'. Such research would be difficult, if not impossible, to achieve on shared, commercial systems.

Shared virtual memory and generalized speedup

NASA Technical Reports Server (NTRS)

Sun, Xian-He; Zhu, Jianping

1994-01-01

Generalized speedup is defined as parallel speed over sequential speed. The generalized speedup and its relation with other existing performance metrics, such as traditional speedup, efficiency, scalability, etc., are carefully studied. In terms of the introduced asymptotic speed, it was shown that the difference between the generalized speedup and the traditional speedup lies in the definition of the efficiency of uniprocessor processing, which is a very important issue in shared virtual memory machines. A scientific application was implemented on a KSR-1 parallel computer. Experimental and theoretical results show that the generalized speedup is distinct from the traditional speedup and provides a more reasonable measurement. In the study of different speedups, various causes of superlinear speedup are also presented.

Error recovery in shared memory multiprocessors using private caches

NASA Technical Reports Server (NTRS)

Wu, Kun-Lung; Fuchs, W. Kent; Patel, Janak H.

1990-01-01

The problem of recovering from processor transient faults in shared memory multiprocesses systems is examined. A user-transparent checkpointing and recovery scheme using private caches is presented. Processes can recover from errors due to faulty processors by restarting from the checkpointed computation state. Implementation techniques using checkpoint identifiers and recovery stacks are examined as a means of reducing performance degradation in processor utilization during normal execution. This cache-based checkpointing technique prevents rollback propagation, provides rapid recovery, and can be integrated into standard cache coherence protocols. An analytical model is used to estimate the relative performance of the scheme during normal execution. Extensions to take error latency into account are presented.

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.

Towards memory-aware services and browsing through lifelogging sensing.

PubMed

Arcega, Lorena; Font, Jaime; Cetina, Carlos

2013-11-05

Every day we receive lots of information through our senses that is lost forever, because it lacked the strength or the repetition needed to generate a lasting memory. Combining the emerging Internet of Things and lifelogging sensors, we believe it is possible to build up a Digital Memory (Dig-Mem) in order to complement the fallible memory of people. This work shows how to realize the Dig-Mem in terms of interactions, affinities, activities, goals and protocols. We also complement this Dig-Mem with memory-aware services and a Dig-Mem browser. Furthermore, we propose a RFID Tag-Sharing technique to speed up the adoption of Dig-Mem. Experimentation reveals an improvement of the user understanding of Dig-Mem as time passes, compared to natural memories where the level of detail decreases over time.

TDP-43 pathology and memory impairment in elders without pathologic diagnoses of AD or FTLD

PubMed Central

Yu, Lei; Wilson, Robert S.; Chen, Er-Yun; Bennett, David A.; Schneider, Julie A.

2017-01-01

Objective: To investigate the association of TAR DNA-binding protein 43 (TDP-43) pathology with memory, other cognitive domains, and dementia in community-dwelling elders without pathologic diagnoses of Alzheimer disease (AD) or frontotemporal lobar degeneration (FTLD). Methods: Of 1,058 autopsied participants, 343 (32.4%) did not have pathologic diagnoses of AD or FTLD. Diagnosis of dementia was based on clinical evaluation and cognitive performance tests, which were used to create summary measures of global cognition and of 5 cognitive domains. TDP-43 pathology evaluated in 6 brain regions by immunohistochemistry was converted into a summary measure of TDP-43 severity. Results: Of 343 participants, 135 (39.4%) had TDP-43 pathology with a mean TDP-43 severity score of 0.394 (SD 0.490). TDP-43 inclusions were confined to the amygdala (stage 1) in 43.7% of participants, 40% showed additional involvement of the hippocampus or entorhinal cortex (stages 2), while fewer (16.3%) showed additional TDP-43 pathology in the temporal and frontal cortices (stage 3). Severity of TDP-43 pathology was independently related to lower function in global cognition and episodic and semantic memory while increased odds of dementia was only a trend. When participants with hippocampal sclerosis (HS) were excluded from the models, TDP-43 pathology remained associated with lower episodic memory but relationships with global cognition, semantic memory, and dementia were attenuated. Conclusions: TDP-43 pathology in elders, without pathologic diagnoses of AD or FTLD, is common and independently associated with lower function in episodic memory, while its associations with global cognitive impairment and dementia are difficult to separate from HS. PMID:28087828

The storage capacity of Potts models for semantic memory retrieval

NASA Astrophysics Data System (ADS)

Kropff, Emilio; Treves, Alessandro

2005-08-01

We introduce and analyse a minimal network model of semantic memory in the human brain. The model is a global associative memory structured as a collection of N local modules, each coding a feature, which can take S possible values, with a global sparseness a (the average fraction of features describing a concept). We show that, under optimal conditions, the number cM of modules connected on average to a module can range widely between very sparse connectivity (high dilution, c_{M}/N\\to 0 ) and full connectivity (c_{M}\\to N ), maintaining a global network storage capacity (the maximum number pc of stored and retrievable concepts) that scales like pc~cMS2/a, with logarithmic corrections consistent with the constraint that each synapse may store up to a fraction of a bit.

Optimal Foraging in Semantic Memory

ERIC Educational Resources Information Center

Hills, Thomas T.; Jones, Michael N.; Todd, Peter M.

2012-01-01

Do humans search in memory using dynamic local-to-global search strategies similar to those that animals use to forage between patches in space? If so, do their dynamic memory search policies correspond to optimal foraging strategies seen for spatial foraging? Results from a number of fields suggest these possibilities, including the shared…

Social Support, Social Strain, and Cognitive Function Among Community-Dwelling U.S. Chinese Older Adults.

PubMed

Ge, Shaoqing; Wu, Bei; Bailey, Donald E; Dong, XinQi

2017-07-01

Limited research is available on the relationship between social support, social strain, and cognitive function among community-dwelling U.S. Chinese older adults. This study aims to examine the associations between social support/strain and cognitive outcomes. Data were drawn from the Population-Based Study of Chinese Elderly (N = 3,159). Cognitive function was measured by a battery of tests including the East Boston Memory Test, the Digit Span Backwards assessment, and the Symbol Digit Modalities Test. Social support and strain were measured by the scales drawn from the Health and Retirement study. Multiple regression analyses were conducted. Social support was significantly associated with global cognitive function (β = .11, SE = .02, p < .001), episodic memory (β = .11, SE = .03, p < .001), working memory (β = .18, SE = .08, p < .05), and executive function (β = 1.44, SE = .37, p < .001). Social strain was significantly associated with global cognitive function (β = .23, SE = .05, p < .001), episodic memory (β = .27, SE = .07, p < .001), working memory (β = .34, SE = .17, p < .05), and executive function (β = 2.75, SE = .85, p < .01). In terms of sources of social support/strain, higher support from friends was significantly associated with higher global cognitive function (β = .04, SE = .02, p < .05), higher episodic memory (β = .05, SE = .02, p < .05), and higher executive function (β = .71, SE = .29, p < .05). Higher strain from spouse was significantly associated with higher global cognitive function (β = .10, SE = .03, p < .01), higher episodic memory (β = .11, SE = .04, p < .01), and higher executive function (β = 1.28, SE = .49, p < .01). Higher strain from friends was significantly associated with higher executive function (β = 3.59, SE = 1.17, p < .01). Social support and strain were associated with cognitive outcomes. Future longitudinal studies should be conducted. © The Author 2017. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Multi-processor including data flow accelerator module

DOEpatents

Davidson, George S.; Pierce, Paul E.

1990-01-01

An accelerator module for a data flow computer includes an intelligent memory. The module is added to a multiprocessor arrangement and uses a shared tagged memory architecture in the data flow computer. The intelligent memory module assigns locations for holding data values in correspondence with arcs leading to a node in a data dependency graph. Each primitive computation is associated with a corresponding memory cell, including a number of slots for operands needed to execute a primitive computation, a primitive identifying pointer, and linking slots for distributing the result of the cell computation to other cells requiring that result as an operand. Circuitry is provided for utilizing tag bits to determine automatically when all operands required by a processor are available and for scheduling the primitive for execution in a queue. Each memory cell of the module may be associated with any of the primitives, and the particular primitive to be executed by the processor associated with the cell is identified by providing an index, such as the cell number for the primitive, to the primitive lookup table of starting addresses. The module thus serves to perform functions previously performed by a number of sections of data flow architectures and coexists with conventional shared memory therein. A multiprocessing system including the module operates in a hybrid mode, wherein the same processing modules are used to perform some processing in a sequential mode, under immediate control of an operating system, while performing other processing in a data flow mode.

Creating a duet: The Couples Life Story Approach in the United States and Japan

PubMed Central

Ingersoll-Dayton, Berit; Spencer, Beth; Campbell, Ruth; Kurokowa, Yukiko; Ito, Mio

2015-01-01

There is a global need for interventions that help couples who are dealing with dementia. This paper describes the way in which interventionists from the United States and Japan participated in the development of an intervention for dyads in which one person is experiencing memory loss. The 5-week intervention, the Couples Life Story Approach, helps dyads to reminisce about their life together as a couple, to work on their patterns of communication, and to develop a Life Story Book. Based on an analysis of cases conducted in the United States (n = 20 couples) and Japan (n = 9 couples), this paper highlights the cross-fertilization process that has occurred as interventionists from the two countries have shared their experiences with one another. Using case illustrations, the discussion focuses on the clinical themes that have emerged for couples in the United States and Japan. PMID:24627456

Early Experiences Writing Performance Portable OpenMP 4 Codes

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

Joubert, Wayne; Hernandez, Oscar R

In this paper, we evaluate the recently available directives in OpenMP 4 to parallelize a computational kernel using both the traditional shared memory approach and the newer accelerator targeting capabilities. In addition, we explore various transformations that attempt to increase application performance portability, and examine the expressiveness and performance implications of using these approaches. For example, we want to understand if the target map directives in OpenMP 4 improve data locality when mapped to a shared memory system, as opposed to the traditional first touch policy approach in traditional OpenMP. To that end, we use recent Cray and Intel compilersmore » to measure the performance variations of a simple application kernel when executed on the OLCF s Titan supercomputer with NVIDIA GPUs and the Beacon system with Intel Xeon Phi accelerators attached. To better understand these trade-offs, we compare our results from traditional OpenMP shared memory implementations to the newer accelerator programming model when it is used to target both the CPU and an attached heterogeneous device. We believe the results and lessons learned as presented in this paper will be useful to the larger user community by providing guidelines that can assist programmers in the development of performance portable code.« less

The Automatic Parallelisation of Scientific Application Codes Using a Computer Aided Parallelisation Toolkit

NASA Technical Reports Server (NTRS)

Ierotheou, C.; Johnson, S.; Leggett, P.; Cross, M.; Evans, E.; Jin, Hao-Qiang; Frumkin, M.; Yan, J.; Biegel, Bryan (Technical Monitor)

2001-01-01

The shared-memory programming model is a very effective way to achieve parallelism on shared memory parallel computers. Historically, the lack of a programming standard for using directives and the rather limited performance due to scalability have affected the take-up of this programming model approach. Significant progress has been made in hardware and software technologies, as a result the performance of parallel programs with compiler directives has also made improvements. The introduction of an industrial standard for shared-memory programming with directives, OpenMP, has also addressed the issue of portability. In this study, we have extended the computer aided parallelization toolkit (developed at the University of Greenwich), to automatically generate OpenMP based parallel programs with nominal user assistance. We outline the way in which loop types are categorized and how efficient OpenMP directives can be defined and placed using the in-depth interprocedural analysis that is carried out by the toolkit. We also discuss the application of the toolkit on the NAS Parallel Benchmarks and a number of real-world application codes. This work not only demonstrates the great potential of using the toolkit to quickly parallelize serial programs but also the good performance achievable on up to 300 processors for hybrid message passing and directive-based parallelizations.

Periodic oscillation of higher-order bidirectional associative memory neural networks with periodic coefficients and delays

NASA Astrophysics Data System (ADS)

Ren, Fengli; Cao, Jinde

2007-03-01

In this paper, several sufficient conditions are obtained ensuring existence, global attractivity and global asymptotic stability of the periodic solution for the higher-order bidirectional associative memory neural networks with periodic coefficients and delays by using the continuation theorem of Mawhin's coincidence degree theory, the Lyapunov functional and the non-singular M-matrix. Two examples are exploited to illustrate the effectiveness of the proposed criteria. These results are more effective than the ones in the literature for some neural networks, and can be applied to the design of globally attractive or globally asymptotically stable networks and thus have important significance in both theory and applications.

Satellite Image Mosaic Engine

NASA Technical Reports Server (NTRS)

Plesea, Lucian

2006-01-01

A computer program automatically builds large, full-resolution mosaics of multispectral images of Earth landmasses from images acquired by Landsat 7, complete with matching of colors and blending between adjacent scenes. While the code has been used extensively for Landsat, it could also be used for other data sources. A single mosaic of as many as 8,000 scenes, represented by more than 5 terabytes of data and the largest set produced in this work, demonstrated what the code could do to provide global coverage. The program first statistically analyzes input images to determine areas of coverage and data-value distributions. It then transforms the input images from their original universal transverse Mercator coordinates to other geographical coordinates, with scaling. It applies a first-order polynomial brightness correction to each band in each scene. It uses a data-mask image for selecting data and blending of input scenes. Under control by a user, the program can be made to operate on small parts of the output image space, with check-point and restart capabilities. The program runs on SGI IRIX computers. It is capable of parallel processing using shared-memory code, large memories, and tens of central processing units. It can retrieve input data and store output data at locations remote from the processors on which it is executed.

Specific memory impairment following neonatal encephalopathy in term-born children.

PubMed

van Handel, Mariëlle; de Sonneville, Leo; de Vries, Linda S; Jongmans, Marian J; Swaab, Hanna

2012-01-01

This study examines short-term memory, verbal working memory, episodic long-term memory, and intelligence in 32 children with mild neonatal encephalopathy (NE), 39 children with moderate NE, 10 children with NE who developed cerebral palsy (CP), and 53 comparison children, at the age of 9 to 10 years. in addition to a global effect on intelligence, NE had a specific effect on verbal working memory, verbal and visuo-spatial long-term memory, and learning, which was associated with degree of NE. Although these memory problems occurred in children without CP, they were more pronounced when children had also developed CP.

Modulation of learning and memory by the genetic disruption of circadian oscillator populations.

PubMed

Snider, Kaitlin H; Obrietan, Karl

2018-06-23

While a rich literature has documented that the efficiency of learning and memory varies across circadian time, a close survey of that literature reveals extensive heterogeneity in the time of day (TOD) when peak cognitive performance occurs. Moreover, most previous experiments in rodents have not focused on the question of discriminating which memory processes (e.g., working memory, memory acquisition, or retrieval) are modulated by the TOD. Here, we use assays of contextual fear conditioning and spontaneous alternation in WT (C57Bl/6 J) mice to survey circadian modulation of hippocampal-dependent memory at multiple timescales - including working memory (seconds to a few minutes), intermediate-term memory (a delay of thirty minutes), and acquisition and retrieval of long-term memory (a delay of two days). Further, in order to test the relative contributions of circadian timing mechanisms to the modulation of memory, a parallel set of studies were performed in mice lacking clock timing mechanisms. These transgenic mice lacked the essential circadian gene Bmal1, either globally (Bmal1 null) or locally (floxed Bmal1 mice which lack Bmal1 in excitatory forebrain neurons, e.g. cortical and hippocampal neurons). Here, we show that in WT mice, retrieval (but not working memory, intermediate-term memory, or acquisition of long-term memory) is modulated by TOD. However, transgenic mouse models lacking Bmal1 - both globally, and only in forebrain excitatory neurons - show deficits regardless of the memory process tested (and lack circadian modulation of retrieval). These results provide new clarity regarding the impact of TOD on hippocampal-dependent memory and support the key role of hippocampal and cortical circadian oscillations in circadian gating of cognition. Copyright © 2018. Published by Elsevier Inc.

Association of KIBRA and memory.

PubMed

Bates, Timothy C; Price, Jackie F; Harris, Sarah E; Marioni, Riccardo E; Fowkes, F Gerry R; Stewart, Marlene C; Murray, Gordon D; Whalley, Lawrence J; Starr, John M; Deary, Ian J

2009-07-24

We report on the association of KIBRA with memory in two samples of older individuals assessed on either memory for semantically unrelated word stimuli (Rey Auditory Verbal Learning Test, n=2091), or a measure of semantically related material (the WAIS Logical Memory Test of prose-passage recall, n=542). SNP rs17070145 was associated with delayed recall of semantically unrelated items, but not with immediate recall for these stimuli, nor with either immediate or delayed recall for semantically related material. The pattern of results suggests a role for the T-->C substitution in intron 9 of KIBRA in a component of episodic memory involved in long-term storage but independent of processes shared with immediate recall such as rehearsal involved in acquisition and rehearsal or processes.

We Have Met Our Past and Our Future: Thanks for the Walk down Memory Lane

ERIC Educational Resources Information Center

Wiseman, Robert C.

2006-01-01

In this article, the author takes the readers for a walk down memory lane on the use of teaching aids. He shares his experience of the good old days of Audio Visual--opaque projector, motion pictures/films, recorders, and overhead projector. Computers have arrived, and now people can make graphics, pictures, motion pictures, and many different…

Dealing with Prospective Memory Demands While Performing an Ongoing Task: Shared Processing, Increased On-Task Focus, or Both?

ERIC Educational Resources Information Center

Rummel, Jan; Smeekens, Bridget A.; Kane, Michael J.

2017-01-01

Prospective memory (PM) is the cognitive ability to remember to fulfill intended action plans at the appropriate future moment. Current theories assume that PM fulfillment draws on attentional processes. Accordingly, pending PM intentions interfere with other ongoing tasks to the extent to which both tasks rely on the same processes. How do people…

An Action Sequence Withheld in Memory Can Delay Execution of Visually Guided Actions: The Generalization of Response Compatibility Interference

ERIC Educational Resources Information Center

Wiediger, Matthew D.; Fournier, Lisa R.

2008-01-01

Withholding an action plan in memory for later execution can delay execution of another action, if the actions share a similar (compatible) action feature (i.e., response hand). This phenomenon, termed compatibility interference (CI), was found for identity-based actions that do not require visual guidance. The authors examined whether CI can…

Relations of Maternal Style and Child Self-Concept to Autobiographical Memories in Chinese, Chinese Immigrant, and European American 3-Year-Olds

ERIC Educational Resources Information Center

Wang, Qi

2006-01-01

The relations of maternal reminiscing style and child self-concept to children's shared and independent autobiographical memories were examined in a sample of 189 three-year-olds and their mothers from Chinese families in China, first-generation Chinese immigrant families in the United States, and European American families. Mothers shared…

Genetic and environmental influences on individual differences in emotion regulation and its relation to working memory in toddlerhood.

PubMed

Wang, Manjie; Saudino, Kimberly J

2013-12-01

This is the first study to explore genetic and environmental contributions to individual differences in emotion regulation in toddlers, and the first to examine the genetic and environmental etiology underlying the association between emotion regulation and working memory. In a sample of 304 same-sex twin pairs (140 MZ, 164 DZ) at age 3, emotion regulation was assessed using the Behavior Rating Scale of the Bayley Scales of Infant Development (BRS; Bayley, 1993), and working memory was measured by the visually cued recall (VCR) task (Zelazo, Jacques, Burack, & Frye, 2002) and several memory tasks from the Mental Scale of the BSID. Based on model-fitting analyses, both emotion regulation and working memory were significantly influenced by genetic and nonshared environmental factors. Shared environmental effects were significant for working memory, but not for emotion regulation. Only genetic factors significantly contributed to the covariation between emotion regulation and working memory.

Genetic and Environmental Influences on Individual Differences in Emotion Regulation and Its Relation to Working Memory in Toddlerhood

PubMed Central

Wang, Manjie; Saudino, Kimberly J.

2014-01-01

This is the first study to explore genetic and environmental contributions to individual differences in emotion regulation in toddlers, and the first to examine the genetic and environmental etiology underlying the association between emotion regulation and working memory. In a sample of 304 same-sex twin pairs (140 MZ, 164 DZ) at age 3, emotion regulation was assessed using the Behavior Rating Scale of the Bayley Scales of Infant Development (BRS; Bayley, 1993), and working memory was measured by the visually cued recall (VCR) task (Zelazo et al., 2002) and several memory tasks from the Mental Scale of BSID. Based on model-fitting analyses, both emotion regulation and working memory were significantly influenced by genetic and nonshared environmental factors. Shared environmental effects were significant for working memory, but not for emotion regulation. Only genetic factors significantly contributed to the covariation between emotion regulation and working memory. PMID:24098922

Autobiographical Memory Sharing in Everyday Life: Characteristics of a Good Story

ERIC Educational Resources Information Center

Baron, Jacqueline M.; Bluck, Susan

2009-01-01

Storytelling is a ubiquitous human activity that occurs across the lifespan as part of everyday life. Studies from three disparate literatures suggest that older adults (as compared to younger adults) are (a) less likely to recall story details, (b) more likely to go off-target when sharing stories, and, in contrast, (c) more likely to receive…

Electrophysiological Activity Generated during the Implicit Association Test: A Study Using Event-Related Potentials

ERIC Educational Resources Information Center

O'Toole, Catriona; Barnes-Holmes, Dermot

2009-01-01

The Implicit Association Test (IAT) examines the differential association of 2 target concepts with 2 attribute concepts. Responding is predicted to be faster on consistent trials, when concepts that are associated in memory share a response key, than on inconsistent trials, when less associated items share a key. In the current study,…

Shared Versus Distributed Memory Multiprocessors

DTIC Science & Technology

1991-01-01

multiprocessors should hawe shared or dis.trimuted meieo-% ha~ trr ~ g ’’~ de~i c4~accio;, S Cm teaicners argue S trongly tor Outiding (li15 tri huted...Applications, MIT Press (1985). 161 D. Gajski et el., "Cedar," Proc. Compcon, pp. 306-309 (Spring 19S9). 171 S. Ahuja, N. Carriero and D. Gelernter, "Linda

The evolution of episodic memory

PubMed Central

Allen, Timothy A.; Fortin, Norbert J.

2013-01-01

One prominent view holds that episodic memory emerged recently in humans and lacks a “(neo)Darwinian evolution” [Tulving E (2002) Annu Rev Psychol 53:1–25]. Here, we review evidence supporting the alternative perspective that episodic memory has a long evolutionary history. We show that fundamental features of episodic memory capacity are present in mammals and birds and that the major brain regions responsible for episodic memory in humans have anatomical and functional homologs in other species. We propose that episodic memory capacity depends on a fundamental neural circuit that is similar across mammalian and avian species, suggesting that protoepisodic memory systems exist across amniotes and, possibly, all vertebrates. The implication is that episodic memory in diverse species may primarily be due to a shared underlying neural ancestry, rather than the result of evolutionary convergence. We also discuss potential advantages that episodic memory may offer, as well as species-specific divergences that have developed on top of the fundamental episodic memory architecture. We conclude by identifying possible time points for the emergence of episodic memory in evolution, to help guide further research in this area. PMID:23754432

Neuroprotective effect of antioxidants on ischaemia and reperfusion-induced cerebral injury.

PubMed

Gupta, Ram; Singh, Manjeet; Sharma, Ajay

2003-08-01

The present study is designed to investigate the effect of dietary flavanoid rutin, micronutrient selenium and garlic oil on ischaemia and reperfusion-induced cerebral injury. Global cerebral ischaemia was induced by occluding right and left common carotid arteries for 10min followed by reperfusion for 24h. Cerebral infarct size was estimated using triphenyltetrazolium chloride staining. Elevated plus maze was employed to estimate short-term memory. Degree of motor incoordination was evaluated using inclined beam-walking test and lateral push test. Mitochondrial thiobarbituric acid reactive substances (TBARS) assay was employed as an index of oxidative stress. Global cerebral ischaemia followed by reperfusion produced a significant impairment in short-term memory and motor coordination and produced a notable increase in mitochondrial TBARS. Administration of rutin and garlic oil before global cerebral ischaemia markedly reduced cerebral infarct size and attenuated impairment in short-term memory and motor coordination. Administration of sodium selenite either before or after global cerebral ischaemia markedly reduced cerebral infarct size and attenuated impairment in short-term memory and motor coordination. The protective effect of rutin, sodium selenite and garlic oil was accompanied by a marked decrease in mitochondrial TBARS. On the basis of these results, it may be suggested that rutin and garlic oil administrated before cerebral ischaemia may scavenge reactive oxygen species and consequently attenuate global cerebral ischaemia and reperfusion-induced cerebral injury. Sodium selenite administrated before and after cerebral ischaemia may be neuroprotective due to its antioxidant effect.

Explaining prompts children to privilege inductively rich properties.

PubMed

Walker, Caren M; Lombrozo, Tania; Legare, Cristine H; Gopnik, Alison

2014-11-01

Four experiments with preschool-aged children test the hypothesis that engaging in explanation promotes inductive reasoning on the basis of shared causal properties as opposed to salient (but superficial) perceptual properties. In Experiments 1a and 1b, 3- to 5-year-old children prompted to explain during a causal learning task were more likely to override a tendency to generalize according to perceptual similarity and instead extend an internal feature to an object that shared a causal property. Experiment 2 replicated this effect of explanation in a case of label extension (i.e., categorization). Experiment 3 demonstrated that explanation improves memory for clusters of causally relevant (non-perceptual) features, but impairs memory for superficial (perceptual) features, providing evidence that effects of explanation are selective in scope and apply to memory as well as inference. In sum, our data support the proposal that engaging in explanation influences children's reasoning by privileging inductively rich, causal properties. Copyright © 2014 Elsevier B.V. All rights reserved.

Power and Performance Trade-offs for Space Time Adaptive Processing

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

Gawande, Nitin A.; Manzano Franco, Joseph B.; Tumeo, Antonino

Computational efficiency – performance relative to power or energy – is one of the most important concerns when designing RADAR processing systems. This paper analyzes power and performance trade-offs for a typical Space Time Adaptive Processing (STAP) application. We study STAP implementations for CUDA and OpenMP on two computationally efficient architectures, Intel Haswell Core I7-4770TE and NVIDIA Kayla with a GK208 GPU. We analyze the power and performance of STAP’s computationally intensive kernels across the two hardware testbeds. We also show the impact and trade-offs of GPU optimization techniques. We show that data parallelism can be exploited for efficient implementationmore » on the Haswell CPU architecture. The GPU architecture is able to process large size data sets without increase in power requirement. The use of shared memory has a significant impact on the power requirement for the GPU. A balance between the use of shared memory and main memory access leads to an improved performance in a typical STAP application.« less

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.

A Tensor Product Formulation of Strassen's Matrix Multiplication Algorithm with Memory Reduction

DOE PAGES

Kumar, B.; Huang, C. -H.; Sadayappan, P.; ...

1995-01-01

In this article, we present a program generation strategy of Strassen's matrix multiplication algorithm using a programming methodology based on tensor product formulas. In this methodology, block recursive programs such as the fast Fourier Transforms and Strassen's matrix multiplication algorithm are expressed as algebraic formulas involving tensor products and other matrix operations. Such formulas can be systematically translated to high-performance parallel/vector codes for various architectures. In this article, we present a nonrecursive implementation of Strassen's algorithm for shared memory vector processors such as the Cray Y-MP. A previous implementation of Strassen's algorithm synthesized from tensor product formulas required working storagemore » of size O(7 n ) for multiplying 2 n × 2 n matrices. We present a modified formulation in which the working storage requirement is reduced to O(4 n ). The modified formulation exhibits sufficient parallelism for efficient implementation on a shared memory multiprocessor. Performance results on a Cray Y-MP8/64 are presented.« less

The global position of the U S forest products industry

Treesearch

Jeffrey P. Prestemon; David N. Wear; Michaela O. Foster

2015-01-01

The United States’ share of global industrial roundwood production has declined since the 1990s. We reviewed data from 1961-2013 to evaluate the extent of this decline for industrial roundwood and derived secondary forest products compared to other major producing countries. We find that the U.S. global share of industrial roundwood peaked at 28 percent in 1999 but...

Dynamic Search and Working Memory in Social Recall

ERIC Educational Resources Information Center

Hills, Thomas T.; Pachur, Thorsten

2012-01-01

What are the mechanisms underlying search in social memory (e.g., remembering the people one knows)? Do the search mechanisms involve dynamic local-to-global transitions similar to semantic search, and are these transitions governed by the general control of attention, associated with working memory span? To find out, we asked participants to…

Mechanisms of Age-Related Decline in Memory Search across the Adult Life Span

ERIC Educational Resources Information Center

Hills, Thomas T.; Mata, Rui; Wilke, Andreas; Samanez-Larkin, Gregory R.

2013-01-01

Three alternative mechanisms for age-related decline in memory search have been proposed, which result from either reduced processing speed (global slowing hypothesis), overpersistence on categories (cluster-switching hypothesis), or the inability to maintain focus on local cues related to a decline in working memory (cue-maintenance hypothesis).…

Interference from mere thinking: mental rehearsal temporarily disrupts recall of motor memory.

PubMed

Yin, Cong; Wei, Kunlin

2014-08-01

Interference between successively learned tasks is widely investigated to study motor memory. However, how simultaneously learned motor memories interact with each other has been rarely studied despite its prevalence in daily life. Assuming that motor memory shares common neural mechanisms with declarative memory system, we made unintuitive predictions that mental rehearsal, as opposed to further practice, of one motor memory will temporarily impair the recall of another simultaneously learned memory. Subjects simultaneously learned two sensorimotor tasks, i.e., visuomotor rotation and gain. They retrieved one memory by either practice or mental rehearsal and then had their memory evaluated. We found that mental rehearsal, instead of execution, impaired the recall of unretrieved memory. This impairment was content-independent, i.e., retrieving either gain or rotation impaired the other memory. Hence, conscious recollection of one motor memory interferes with the recall of another memory. This is analogous to retrieval-induced forgetting in declarative memory, suggesting a common neural process across memory systems. Our findings indicate that motor imagery is sufficient to induce interference between motor memories. Mental rehearsal, currently widely regarded as beneficial for motor performance, negatively affects memory recall when it is exercised for a subset of memorized items. Copyright © 2014 the American Physiological Society.

Long-memory and the sea level-temperature relationship: a fractional cointegration approach.

PubMed

Ventosa-Santaulària, Daniel; Heres, David R; Martínez-Hernández, L Catalina

2014-01-01

Through thermal expansion of oceans and melting of land-based ice, global warming is very likely contributing to the sea level rise observed during the 20th century. The amount by which further increases in global average temperature could affect sea level is only known with large uncertainties due to the limited capacity of physics-based models to predict sea levels from global surface temperatures. Semi-empirical approaches have been implemented to estimate the statistical relationship between these two variables providing an alternative measure on which to base potentially disrupting impacts on coastal communities and ecosystems. However, only a few of these semi-empirical applications had addressed the spurious inference that is likely to be drawn when one nonstationary process is regressed on another. Furthermore, it has been shown that spurious effects are not eliminated by stationary processes when these possess strong long memory. Our results indicate that both global temperature and sea level indeed present the characteristics of long memory processes. Nevertheless, we find that these variables are fractionally cointegrated when sea-ice extent is incorporated as an instrumental variable for temperature which in our estimations has a statistically significant positive impact on global sea level.

Cognitive outcome after stereotactic amygdalohippocampectomy.

PubMed

Vojtěch, Zdeněk; Krámská, Lenka; Malíková, Hana; Seltenreichová, Kateřina; Procházka, Tomáš; Kalina, Miroslav; Liščák, Roman

2012-06-01

We sought to determine the neuropsychological outcome after stereotactic radiofrequency amygdalohippocampectomy performed for intractable mesial temporal lobe epilepsy. The article describes the cases of 31 patients who were evaluated using the Wechsler Adult Intelligence Scale-Revised and the Wechsler Memory Scale-Revised prior to, and one year after, surgery. Patients showed increases in their mean Full Scale, Verbal and Performance IQ scores of 4, 3 and 4 IQ points respectively (p<.05). 5 (17.2%), 4 (13.8%) and 4 (13.3%) patients improved in their Full-scale, Verbal and Performance IQ respectively. No significant changes were found in memory performance - with a mean increase of 1, 3 and 0 MQ points in Global, Verbal and Visual memory respectively (p<.05). Global memory improved in 3 (10.3%) patients, verbal memory in 1 (3.4%) and 1 patient (3.3%) showed deterioration in visual memory. Our results provide evidence for unchanged memory in patients with MTLE after the procedure. No verbal memory deterioration was detected in any of our patients, while improvements were found in intellectual performance. The results suggest that stereotactic radiofrequency amygdalahippocampectomy could be superior to open surgery in terms of its neurocognitive outcomes. A larger randomised trial of these approaches is justified. Copyright © 2012 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

Distributed-Memory Fast Maximal Independent Set

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

Kanewala Appuhamilage, Thejaka Amila J.; Zalewski, Marcin J.; Lumsdaine, Andrew

The Maximal Independent Set (MIS) graph problem arises in many applications such as computer vision, information theory, molecular biology, and process scheduling. The growing scale of MIS problems suggests the use of distributed-memory hardware as a cost-effective approach to providing necessary compute and memory resources. Luby proposed four randomized algorithms to solve the MIS problem. All those algorithms are designed focusing on shared-memory machines and are analyzed using the PRAM model. These algorithms do not have direct efficient distributed-memory implementations. In this paper, we extend two of Luby’s seminal MIS algorithms, “Luby(A)” and “Luby(B),” to distributed-memory execution, and we evaluatemore » their performance. We compare our results with the “Filtered MIS” implementation in the Combinatorial BLAS library for two types of synthetic graph inputs.« less

Towards Memory-Aware Services and Browsing through Lifelogging Sensing

PubMed Central

Arcega, Lorena; Font, Jaime; Cetina, Carlos

2013-01-01

Every day we receive lots of information through our senses that is lost forever, because it lacked the strength or the repetition needed to generate a lasting memory. Combining the emerging Internet of Things and lifelogging sensors, we believe it is possible to build up a Digital Memory (Dig-Mem) in order to complement the fallible memory of people. This work shows how to realize the Dig-Mem in terms of interactions, affinities, activities, goals and protocols. We also complement this Dig-Mem with memory-aware services and a Dig-Mem browser. Furthermore, we propose a RFID Tag-Sharing technique to speed up the adoption of Dig-Mem. Experimentation reveals an improvement of the user understanding of Dig-Mem as time passes, compared to natural memories where the level of detail decreases over time. PMID:24196436

Donepezil attenuates hippocampal neuronal damage and cognitive deficits after global cerebral ischemia in gerbils.

PubMed

Min, Dongyu; Mao, Xiaoyuan; Wu, Kuncan; Cao, Yonggang; Guo, Feng; Zhu, Shu; Xie, Ni; Wang, Lei; Chen, Tianbao; Shaw, Chris; Cai, Jiqun

2012-02-21

Decreased cerebral blood flow causes cognitive impairments and neuronal injury in vascular dementia. In the present study, we reported that donepezil, a cholinesterase inhibitor, improved transient global cerebral ischemia-induced spatial memory impairment in gerbils. Treatment with 5mg/kg of donepezil for 21 consecutive days following a 10-min period of ischemia significantly inhibited delayed neuronal death in the hippocampal CA1 region. In Morris water maze test, memory impairment was significantly improved by donepezil treatment. Western blot analysis showed that donepezil treatment prevented reductions in p-CaMKII and p-CREB protein levels in the hippocampus. These results suggest that donepezil attenuates the memory deficit induced by transient global cerebral ischemia and this neuroprotection may be associated with the phosphorylation of CaMKII and CERB in the hippocampus. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Simulation Analysis of Data Sharing in Shared Memory Multiprocessors

DTIC Science & Technology

1989-02-24

LIMITATION OF ABSTRACT Same as Report (SAR) 18. NUMBER OF PAGES 178 19a. NAME OF RESPONSIBLE PERSON a. REPORT unclassified b . ABSTRACT unclassified...work. Andrea Casotto (CELL), Steve McGrogan (SPICE), Srinivas Devadas (TOPOP1) and Hi-Keung Tony Ma (VERIFY) donated the parallel programs and a con...Effect of Block Size on B us Utilization 120 5-14 Ratio of Sharing Bus Cyc les to Total Bus Cycles 120 5-15 Oassification of Bus Cyc les for

Contextual cueing: implicit learning and memory of visual context guides spatial attention.

PubMed

Chun, M M; Jiang, Y

1998-06-01

Global context plays an important, but poorly understood, role in visual tasks. This study demonstrates that a robust memory for visual context exists to guide spatial attention. Global context was operationalized as the spatial layout of objects in visual search displays. Half of the configurations were repeated across blocks throughout the entire session, and targets appeared within consistent locations in these arrays. Targets appearing in learned configurations were detected more quickly. This newly discovered form of search facilitation is termed contextual cueing. Contextual cueing is driven by incidentally learned associations between spatial configurations (context) and target locations. This benefit was obtained despite chance performance for recognizing the configurations, suggesting that the memory for context was implicit. The results show how implicit learning and memory of visual context can guide spatial attention towards task-relevant aspects of a scene.

Adjusting process count on demand for petascale global optimization

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

Sosonkina, Masha; Watson, Layne T.; Radcliffe, Nicholas R.

2012-11-23

There are many challenges that need to be met before efficient and reliable computation at the petascale is possible. Many scientific and engineering codes running at the petascale are likely to be memory intensive, which makes thrashing a serious problem for many petascale applications. One way to overcome this challenge is to use a dynamic number of processes, so that the total amount of memory available for the computation can be increased on demand. This paper describes modifications made to the massively parallel global optimization code pVTdirect in order to allow for a dynamic number of processes. In particular, themore » modified version of the code monitors memory use and spawns new processes if the amount of available memory is determined to be insufficient. The primary design challenges are discussed, and performance results are presented and analyzed.« less

Parallel discrete event simulation: A shared memory approach

NASA Technical Reports Server (NTRS)

Reed, Daniel A.; Malony, Allen D.; Mccredie, Bradley D.

1987-01-01

With traditional event list techniques, evaluating a detailed discrete event simulation model can often require hours or even days of computation time. Parallel simulation mimics the interacting servers and queues of a real system by assigning each simulated entity to a processor. By eliminating the event list and maintaining only sufficient synchronization to insure causality, parallel simulation can potentially provide speedups that are linear in the number of processors. A set of shared memory experiments is presented using the Chandy-Misra distributed simulation algorithm to simulate networks of queues. Parameters include queueing network topology and routing probabilities, number of processors, and assignment of network nodes to processors. These experiments show that Chandy-Misra distributed simulation is a questionable alternative to sequential simulation of most queueing network models.

Exploration versus exploitation in space, mind, and society

PubMed Central

Hills, Thomas T.; Todd, Peter M.; Lazer, David; Redish, A. David; Couzin, Iain D.

2015-01-01

Search is a ubiquitous property of life. Although diverse domains have worked on search problems largely in isolation, recent trends across disciplines indicate that the formal properties of these problems share similar structures and, often, similar solutions. Moreover, internal search (e.g., memory search) shows similar characteristics to external search (e.g., spatial foraging), including shared neural mechanisms consistent with a common evolutionary origin across species. Search problems and their solutions also scale from individuals to societies, underlying and constraining problem solving, memory, information search, and scientific and cultural innovation. In summary, search represents a core feature of cognition, with a vast influence on its evolution and processes across contexts and requiring input from multiple domains to understand its implications and scope. PMID:25487706

Dynamic programming on a shared-memory multiprocessor

NASA Technical Reports Server (NTRS)

Edmonds, Phil; Chu, Eleanor; George, Alan

1993-01-01

Three new algorithms for solving dynamic programming problems on a shared-memory parallel computer are described. All three algorithms attempt to balance work load, while keeping synchronization cost low. In particular, for a multiprocessor having p processors, an analysis of the best algorithm shows that the arithmetic cost is O(n-cubed/6p) and that the synchronization cost is O(absolute value of log sub C n) if p much less than n, where C = (2p-1)/(2p + 1) and n is the size of the problem. The low synchronization cost is important for machines where synchronization is expensive. Analysis and experiments show that the best algorithm is effective in balancing the work load and producing high efficiency.

Regular Latin Dancing and Health Education may Improve Cognition of Late Middle-Aged and Older Latinos

PubMed Central

Marquez, David X.; Wilson, Robert; Aguiñaga, Susan; Vásquez, Priscilla; Fogg, Louis; Yang, Zhi; Wilbur, JoEllen; Hughes, Susan; Spanbauer, Charles

2017-01-01

Disparities exist between Latinos and non-Latino whites in cognitive function. Dance is culturally appropriate and challenges individuals physically and cognitively, yet the impact of regular dancing on cognitive function in older Latinos has not been examined. A two-group pilot trial was employed among inactive, older Latinos. Participants (N = 57) participated in the BAILAMOS© dance program or a health education program. Cognitive test scores were converted to z-scores and measures of global cognition and specific domains (executive function, episodic memory, working memory) were derived. Results revealed a group × time interaction for episodic memory (p<0.05), such that the dance group showed greater improvement in episodic memory than the health education group. A main effect for time for global cognition (p<0.05) was also demonstrated, with participants in both groups improving. Structured Latin dance programs can positively influence episodic memory; and participation in structured programs may improve overall cognition among older Latinos. PMID:28095105

Regular Latin Dancing and Health Education May Improve Cognition of Late Middle-Aged and Older Latinos.

PubMed

Marquez, David X; Wilson, Robert; Aguiñaga, Susan; Vásquez, Priscilla; Fogg, Louis; Yang, Zhi; Wilbur, JoEllen; Hughes, Susan; Spanbauer, Charles

2017-07-01

Disparities exist between Latinos and non-Latino Whites in cognitive function. Dance is culturally appropriate and challenges individuals physically and cognitively, yet the impact of regular dancing on cognitive function in older Latinos has not been examined. A two-group pilot trial was employed among inactive, older Latinos. Participants (N = 57) participated in the BAILAMOS © dance program or a health education program. Cognitive test scores were converted to z-scores and measures of global cognition and specific domains (executive function, episodic memory, working memory) were derived. Results revealed a group × time interaction for episodic memory (p < .05), such that the dance group showed greater improvement in episodic memory than the health education group. A main effect for time for global cognition (p < .05) was also demonstrated, with participants in both groups improving. Structured Latin dance programs can positively influence episodic memory, and participation in structured programs may improve overall cognition among older Latinos.

Global Mental Health: sharing and synthesizing knowledge for sustainable development.

PubMed

O'Donnell, K; O'Donnell, M Lewis

2016-01-01

Global mental health (GMH) is a growing domain with an increasing capacity to positively impact the world community's efforts for sustainable development and wellbeing. Sharing and synthesizing GMH and multi-sectoral knowledge, the focus of this paper, is an important way to support these global efforts. This paper consolidates some of the most recent and relevant 'context resources' [global multi-sector (GMS) materials, emphasizing world reports on major issues] and 'core resources' (GMH materials, including newsletters, texts, conferences, training, etc.). In addition to offering a guided index of materials, it presents an orientation framework (global integration) to help make important information as accessible and useful as possible. Mental health colleagues are encouraged to stay current in GMH and global issues, to engage in the emerging agendas for sustainable development and wellbeing, and to intentionally connect and contribute across sectors. Colleagues in all sectors are encouraged to do likewise, and to take advantage of the wealth of shared and synthesized knowledge in the GMH domain, such as the materials featured in this paper.

Get the gist? The effects of processing depth on false recognition in short-term and long-term memory.

PubMed

Flegal, Kristin E; Reuter-Lorenz, Patricia A

2014-07-01

Gist-based processing has been proposed to account for robust false memories in the converging-associates task. The deep-encoding processes known to enhance verbatim memory also strengthen gist memory and increase distortions of long-term memory (LTM). Recent research has demonstrated that compelling false memory illusions are relatively delay-invariant, also occurring under canonical short-term memory (STM) conditions. To investigate the contributions of gist to false memory at short and long delays, processing depth was manipulated as participants encoded lists of four semantically related words and were probed immediately, following a filled 3- to 4-s retention interval, or approximately 20 min later, in a surprise recognition test. In two experiments, the encoding manipulation dissociated STM and LTM on the frequency, but not the phenomenology, of false memory. Deep encoding at STM increases false recognition rates at LTM, but confidence ratings and remember/know judgments are similar across delays and do not differ as a function of processing depth. These results suggest that some shared and some unique processes underlie false memory illusions at short and long delays.

Multi-GPU and multi-CPU accelerated FDTD scheme for vibroacoustic applications

NASA Astrophysics Data System (ADS)

Francés, J.; Otero, B.; Bleda, S.; Gallego, S.; Neipp, C.; Márquez, A.; Beléndez, A.

2015-06-01

The Finite-Difference Time-Domain (FDTD) method is applied to the analysis of vibroacoustic problems and to study the propagation of longitudinal and transversal waves in a stratified media. The potential of the scheme and the relevance of each acceleration strategy for massively computations in FDTD are demonstrated in this work. In this paper, we propose two new specific implementations of the bi-dimensional scheme of the FDTD method using multi-CPU and multi-GPU, respectively. In the first implementation, an open source message passing interface (OMPI) has been included in order to massively exploit the resources of a biprocessor station with two Intel Xeon processors. Moreover, regarding CPU code version, the streaming SIMD extensions (SSE) and also the advanced vectorial extensions (AVX) have been included with shared memory approaches that take advantage of the multi-core platforms. On the other hand, the second implementation called the multi-GPU code version is based on Peer-to-Peer communications available in CUDA on two GPUs (NVIDIA GTX 670). Subsequently, this paper presents an accurate analysis of the influence of the different code versions including shared memory approaches, vector instructions and multi-processors (both CPU and GPU) and compares them in order to delimit the degree of improvement of using distributed solutions based on multi-CPU and multi-GPU. The performance of both approaches was analysed and it has been demonstrated that the addition of shared memory schemes to CPU computing improves substantially the performance of vector instructions enlarging the simulation sizes that use efficiently the cache memory of CPUs. In this case GPU computing is slightly twice times faster than the fine tuned CPU version in both cases one and two nodes. However, for massively computations explicit vector instructions do not worth it since the memory bandwidth is the limiting factor and the performance tends to be the same than the sequential version with auto-vectorisation and also shared memory approach. In this scenario GPU computing is the best option since it provides a homogeneous behaviour. More specifically, the speedup of GPU computing achieves an upper limit of 12 for both one and two GPUs, whereas the performance reaches peak values of 80 GFlops and 146 GFlops for the performance for one GPU and two GPUs respectively. Finally, the method is applied to an earth crust profile in order to demonstrate the potential of our approach and the necessity of applying acceleration strategies in these type of applications.

A theory of working memory without consciousness or sustained activity

PubMed Central

Trübutschek, Darinka; Marti, Sébastien; Ojeda, Andrés; King, Jean-Rémi; Mi, Yuanyuan; Tsodyks, Misha; Dehaene, Stanislas

2017-01-01

Working memory and conscious perception are thought to share similar brain mechanisms, yet recent reports of non-conscious working memory challenge this view. Combining visual masking with magnetoencephalography, we investigate the reality of non-conscious working memory and dissect its neural mechanisms. In a spatial delayed-response task, participants reported the location of a subjectively unseen target above chance-level after several seconds. Conscious perception and conscious working memory were characterized by similar signatures: a sustained desynchronization in the alpha/beta band over frontal cortex, and a decodable representation of target location in posterior sensors. During non-conscious working memory, such activity vanished. Our findings contradict models that identify working memory with sustained neural firing, but are compatible with recent proposals of ‘activity-silent’ working memory. We present a theoretical framework and simulations showing how slowly decaying synaptic changes allow cell assemblies to go dormant during the delay, yet be retrieved above chance-level after several seconds. DOI: http://dx.doi.org/10.7554/eLife.23871.001 PMID:28718763

US forest products in the global economy

Treesearch

Dave N Wear; Jeff Prestemon; Michaela O. Foster

2015-01-01

The United States’ shares of global industrial roundwood production and derivative products have declined precipitously since the 1990s. We evaluate the extent of these declines compared with those of major producing countries from 1961 to 2013. We find that the US global share of industrial roundwood peaked at 28% in 1999 but by 2013 was at 17%, with the decline...

Multiple-User, Multitasking, Virtual-Memory Computer System

NASA Technical Reports Server (NTRS)

Generazio, Edward R.; Roth, Don J.; Stang, David B.

1993-01-01

Computer system designed and programmed to serve multiple users in research laboratory. Provides for computer control and monitoring of laboratory instruments, acquisition and anlaysis of data from those instruments, and interaction with users via remote terminals. System provides fast access to shared central processing units and associated large (from megabytes to gigabytes) memories. Underlying concept of system also applicable to monitoring and control of industrial processes.

A warm and friendly memorial session for Helmut Oeschler

NASA Astrophysics Data System (ADS)

Cleymans, Jean; Hippolyte, Boris; Kalweit, Alexander; Müntz, Christian; Stroth, Joachim

2018-02-01

A full session was organized in memory of Helmut Oeschler during the 2017 edition of the Strangeness in Quark Matter Conference. It was heart-warming to discuss with the audience his main achievements and share anecdotes about this exceptionally praised and appreciated colleague, who was also a great friend for many at the conference. A brief summary of the session is provided with these proceedings.

Visuospatial working memory in children with autism: the effect of a semantic global organization.

PubMed

Mammarella, Irene C; Giofrè, David; Caviola, Sara; Cornoldi, Cesare; Hamilton, Colin

2014-06-01

It has been reported that individuals with Autism Spectrum Disorders (ASD) perceive visual scenes as a sparse set of details rather than as a congruent and meaningful unit, failing in the extraction of the global configuration of the scene. In the present study, children with ASD were compared with typically developing (TD) children, in a visuospatial working memory task, the Visual Patterns Test (VPT). The VPT array was manipulated to vary the semantic affordance of the pattern, high semantic (global) vs. low semantic; temporal parameters were also manipulated within the change detection protocol. Overall, there was no main effect associated with Group, however there was a significant effect associated with Semantics, which was further qualified by an interaction between the Group and Semantic factors; there was only a significant effect of semantics in the TD group. The findings are discussed in light of the weak central coherence theory where the ASD group are unable to make use of long term memory semantics in order to construct global representations of the array. Copyright © 2014 Elsevier Ltd. All rights reserved.

Building Intercultural Understandings through Global Literature

ERIC Educational Resources Information Center

Martens, Prisca; Martens, Ray; Doyle, Michelle Hassay; Loomis, Jenna; Fuhrman, Laura; Furnari, Christie; Soper, Elizabeth; Stout, Robbie

2015-01-01

In this article the authors share how they use global literature picturebooks with pre-kindergarten, kindergarten, and first grade children in the context of A Curriculum That is International to develop the children's intercultural understandings. The picturebooks, shared through read alouds, individual and partner reading, and browsing, is…

Global Practices of Interprofessional Education (IPE) and Relevant International Activities.

PubMed

Arakawa, Naoko

2017-01-01

Activities related to interprofessional education (IPE) vary between countries according to local and national health needs and systems. The International Pharmaceutical Federation (FIP) Education Initiative endeavors to provide a global vision in IPE by the sharing of experiences and gathering of evidence collaboratively to facilitate country-level initiatives. The purpose of this paper is to contribute to the further development of IPE activities in pharmacy in Japan through sharing global perspectives and activities related to IPE. FIP Education Initiative published the Interprofessional Education in a Pharmacy Context: Global Report in September 2015, which marked a milestone in the growing recognition of IPE in pharmacy globally. The paper shared global and regional perspectives and experiences in IPE in pharmacy, both from the report and FIP activities. This paper can be seen as a snapshot of IPE-related international activities, which enables gaps and challenges in implementing IPE activities in Japan to be identified. This paper provides an opportunity to explore global trends and initiatives regarding IPE, and to consider how to form and implement IPE specifically based on Japanese health needs and systems.

Delayed degeneration of the left fornical crus with verbal memory impairment in a patient with mild traumatic brain injury

PubMed Central

Jang, Sung Ho; Seo, Jeong Pyo

2017-01-01

Abstract Rationale: We report on a patient who showed delayed degeneration of the left fornical crus with verbal memory impairment following mild traumatic brain injury (TBI), which was demonstrated by diffusion tensor tractography (DTT). Patient concerns: fter flexion and hyperextension of her head to the opposite side, the patient experienced a dazed feeling for a while at the time of head trauma. The patient's Glasgow Coma Scale score was 15, and mini-mental state examination score was 30. Diagnoses: A 50-year-old right-handed female with 12 years of education suffered from head trauma resulting from a car accident. Interventions: A The patient showed normal memory function at one year after onset: the Memory Assessment Scale (global memory: 124 (95 percentile (%ile)), verbal memory: 111 (77%ile), and visual memory: 132 (98%ile) (A percentile is a measure used in statistics indicating the value below which a given percentage of observations in a group of observations fall). However, the patient began to experience decline of memory function such as forgetfulness at approximately 1.5 years after onset. On the 2-year evaluation, she showed decrement of memory function (global memory: 108 (70%ile), verbal memory: 86 (18%ile), and visual memory: 129 (97%ile). Outcomes: On 1-year DTT, the integrity of the fornix was well preserved between the fornical column and fornical crus. However, on 2-year DTT, a discontinuation was observed in the left fornical crus. Lessons: Delayed degeneration of the left fornical crus was demonstrated in a patient who showed delayed onset of verbal memory impairment following mild TBI. PMID:29390470

Knowledge of memory functions in European and Asian American adults and children: the relation to autobiographical memory.

PubMed

Wang, Qi; Koh, Jessie Bee Kim; Song, Qingfang; Hou, Yubo

2015-01-01

This study investigated explicit knowledge of autobiographical memory functions using a newly developed questionnaire. European and Asian American adults (N = 57) and school-aged children (N = 68) indicated their agreement with 13 statements about why people think about and share memories pertaining to four broad functions-self, social, directive and emotion regulation. Children were interviewed for personal memories concurrently with the memory function knowledge assessment and again 3 months later. It was found that adults agreed to the self, social and directive purposes of memory to a greater extent than did children, whereas European American children agreed to the emotion regulation purposes of memory to a greater extent than did European American adults. Furthermore, European American children endorsed more self and emotion regulation functions than did Asian American children, whereas Asian American adults endorsed more directive functions than did European American adults. Children's endorsement of memory functions, particularly social functions, was associated with more detailed and personally meaningful memories. These findings are informative for the understanding of developmental and cultural influences on memory function knowledge and of the relation of such knowledge to autobiographical memory development.

Remembering Nancy. 25 Members of the Montessori Community Share Their Reflections on the Death of the AMS Founder.

ERIC Educational Resources Information Center

Turner, Joy; And Others

1995-01-01

Twenty-five members of the Montessori community share their memories of Dr. Nancy McCormick Rambusch, charismatic founder of the American Montessori movement, early childhood professional, and innovative educator, who died of pancreatic cancer on October 27, 1994. Rambusch's work of 40 years now flowers as an institutionalized educational program…

Shared Values as Anchors of a Learning Community: A Case Study in Information Systems Design

ERIC Educational Resources Information Center

Giordano, Daniela

2004-01-01

This paper examines the role in both individual and organizational learning of the system of values sustained by a community undertaking a design task. The discussion is based on the results of a longitudinal study of a community of novice information system designers supported by a Web-based shared design memory which allows reuse of design…

Literacy outcomes of children with early childhood speech sound disorders: impact of endophenotypes.

PubMed

Lewis, Barbara A; Avrich, Allison A; Freebairn, Lisa A; Hansen, Amy J; Sucheston, Lara E; Kuo, Iris; Taylor, H Gerry; Iyengar, Sudha K; Stein, Catherine M

2011-12-01

To demonstrate that early childhood speech sound disorders (SSD) and later school-age reading, written expression, and spelling skills are influenced by shared endophenotypes that may be in part genetic. Children with SSD and their siblings were assessed at early childhood (ages 4-6 years) and followed at school age (7-12 years). The relationship of shared endophenotypes with early childhood SSD and school-age outcomes and the shared genetic influences on these outcomes were examined. Structural equation modeling demonstrated that oral motor skills, phonological awareness, phonological memory, vocabulary, and speeded naming have varying influences on reading decoding, spelling, spoken language, and written expression at school age. Genetic linkage studies demonstrated linkage for reading, spelling, and written expression measures to regions on chromosomes 1, 3, 6, and 15 that were previously linked to oral motor skills, articulation, phonological memory, and vocabulary at early childhood testing. Endophenotypes predict school-age literacy outcomes over and above that predicted by clinical diagnoses of SSD or language impairment. Findings suggest that these shared endophenotypes and common genetic influences affect early childhood SSD and later school-age reading, spelling, spoken language, and written expression skills.

Literacy Outcomes of Children With Early Childhood Speech Sound Disorders: Impact of Endophenotypes

PubMed Central

Lewis, Barbara A.; Avrich, Allison A.; Freebairn, Lisa A.; Hansen, Amy J.; Sucheston, Lara E.; Kuo, Iris; Taylor, H. Gerry; Iyengar, Sudha K.; Stein, Catherine M.

2012-01-01

Purpose To demonstrate that early childhood speech sound disorders (SSD) and later school-age reading, written expression, and spelling skills are influenced by shared endophenotypes that may be in part genetic. Method Children with SSD and their siblings were assessed at early childhood (ages 4–6 years) and followed at school age (7–12 years). The relationship of shared endophenotypes with early childhood SSD and school-age outcomes and the shared genetic influences on these outcomes were examined. Results Structural equation modeling demonstrated that oral motor skills, phonological awareness, phonological memory, vocabulary, and speeded naming have varying influences on reading decoding, spelling, spoken language, and written expression at school age. Genetic linkage studies demonstrated linkage for reading, spelling, and written expression measures to regions on chromosomes 1, 3, 6, and 15 that were previously linked to oral motor skills, articulation, phonological memory, and vocabulary at early childhood testing. Conclusions Endophenotypes predict school-age literacy outcomes over and above that predicted by clinical diagnoses of SSD or language impairment. Findings suggest that these shared endophenotypes and common genetic influences affect early childhood SSD and later school-age reading, spelling, spoken language, and written expression skills. PMID:21930616

A Biometric Latent Curve Analysis of Memory Decline in Older Men of the NAS-NRC Twin Registry

PubMed Central

McArdle, John J.; Plassman, Brenda L.

2010-01-01

Previous research has shown cognitive abilities to have different biometric patterns of age-changes. Here we examined the variation in episodic memory (Words Recalled) for over 6,000 twin pairs who were initially aged 59-75, and were subsequently re-assessed up to three more times over 12 years. In cross-sectional analyses, variation in Education was explained by strong additive genetic influences (~43%) together with shared family influences (~35%) that were independent of age. The longitudinal phenotypic analysis of the Word Recall task showed systematic linear declines over age, but with positive influences of Education and Retesting. The longitudinal biometric estimation yielded: (a) A separation of non-shared environmental influences and transient measurement error (~50%): (b) Strong additive genetic components of this latent curve (~70% at age 60) with increases over age that reach about 90% by age 90. (c) The minor influences of shared family environment (~17% at age 60) were effectively eliminated by age 75. (d) Non-shared environmental effects play an important role over most of the life-span (peak of 42% at age 70) but their relative role diminishes after age 75. PMID:19404731

Development of Low Parasitic Light Sensitivity and Low Dark Current 2.8 μm Global Shutter Pixel †

PubMed Central

Yokoyama, Toshifumi; Tsutsui, Masafumi; Suzuki, Masakatsu; Nishi, Yoshiaki; Mizuno, Ikuo; Lahav, Assaf

2018-01-01

We developed a low parasitic light sensitivity (PLS) and low dark current 2.8 μm global shutter pixel. We propose a new inner lens design concept to realize both low PLS and high quantum efficiency (QE). 1/PLS is 7700 and QE is 62% at a wavelength of 530 nm. We also propose a new storage-gate based memory node for low dark current. P-type implants and negative gate biasing are introduced to suppress dark current at the surface of the memory node. This memory node structure shows the world smallest dark current of 9.5 e−/s at 60 °C. PMID:29370146

Development of Low Parasitic Light Sensitivity and Low Dark Current 2.8 μm Global Shutter Pixel.

PubMed

Yokoyama, Toshifumi; Tsutsui, Masafumi; Suzuki, Masakatsu; Nishi, Yoshiaki; Mizuno, Ikuo; Lahav, Assaf

2018-01-25

Abstract : We developed a low parasitic light sensitivity (PLS) and low dark current 2.8 μm global shutter pixel. We propose a new inner lens design concept to realize both low PLS and high quantum efficiency (QE). 1/PLS is 7700 and QE is 62% at a wavelength of 530 nm. We also propose a new storage-gate based memory node for low dark current. P-type implants and negative gate biasing are introduced to suppress dark current at the surface of the memory node. This memory node structure shows the world smallest dark current of 9.5 e - /s at 60 °C.

Optimal global value of information trials: better aligning manufacturer and decision maker interests and enabling feasible risk sharing.

PubMed

Eckermann, Simon; Willan, Andrew R

2013-05-01

Risk sharing arrangements relate to adjusting payments for new health technologies given evidence of their performance over time. Such arrangements rely on prospective information regarding the incremental net benefit of the new technology, and its use in practice. However, once the new technology has been adopted in a particular jurisdiction, randomized clinical trials within that jurisdiction are likely to be infeasible and unethical in the cases where they would be most helpful, i.e. with current evidence of positive while uncertain incremental health and net monetary benefit. Informed patients in these cases would likely be reluctant to participate in a trial, preferring instead to receive the new technology with certainty. Consequently, informing risk sharing arrangements within a jurisdiction is problematic given the infeasibility of collecting prospective trial data. To overcome such problems, we demonstrate that global trials facilitate trialling post adoption, leading to more complete and robust risk sharing arrangements that mitigate the impact of costs of reversal on expected value of information in jurisdictions who adopt while a global trial is undertaken. More generally, optimally designed global trials offer distinct advantages over locally optimal solutions for decision makers and manufacturers alike: avoiding opportunity costs of delay in jurisdictions that adopt; overcoming barriers to evidence collection; and improving levels of expected implementation. Further, the greater strength and translatability of evidence across jurisdictions inherent in optimal global trial design reduces barriers to translation across jurisdictions characteristic of local trials. Consequently, efficiently designed global trials better align the interests of decision makers and manufacturers, increasing the feasibility of risk sharing and the expected strength of evidence over local trials, up until the point that current evidence is globally sufficient.

Efficient accesses of data structures using processing near memory

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

Jayasena, Nuwan S.; Zhang, Dong Ping; Diez, Paula Aguilera

Systems, apparatuses, and methods for implementing efficient queues and other data structures. A queue may be shared among multiple processors and/or threads without using explicit software atomic instructions to coordinate access to the queue. System software may allocate an atomic queue and corresponding queue metadata in system memory and return, to the requesting thread, a handle referencing the queue metadata. Any number of threads may utilize the handle for accessing the atomic queue. The logic for ensuring the atomicity of accesses to the atomic queue may reside in a management unit in the memory controller coupled to the memory wheremore » the atomic queue is allocated.« less

C-MOS array design techniques: SUMC multiprocessor system study

NASA Technical Reports Server (NTRS)

Clapp, W. A.; Helbig, W. A.; Merriam, A. S.

1972-01-01

The current capabilities of LSI techniques for speed and reliability, plus the possibilities of assembling large configurations of LSI logic and storage elements, have demanded the study of multiprocessors and multiprocessing techniques, problems, and potentialities. Evaluated are three previous systems studies for a space ultrareliable modular computer multiprocessing system, and a new multiprocessing system is proposed that is flexibly configured with up to four central processors, four 1/0 processors, and 16 main memory units, plus auxiliary memory and peripheral devices. This multiprocessor system features a multilevel interrupt, qualified S/360 compatibility for ground-based generation of programs, virtual memory management of a storage hierarchy through 1/0 processors, and multiport access to multiple and shared memory units.

Global asymptotic stability of hybrid bidirectional associative memory neural networks with time delays

NASA Astrophysics Data System (ADS)

Arik, Sabri

2006-02-01

This Letter presents a sufficient condition for the existence, uniqueness and global asymptotic stability of the equilibrium point for bidirectional associative memory (BAM) neural networks with distributed time delays. The results impose constraint conditions on the network parameters of neural system independently of the delay parameter, and they are applicable to all bounded continuous non-monotonic neuron activation functions. The results are also compared with the previous results derived in the literature.

Global Existence of Classical Solutions to the Equations of Motion for Materials with Fading Memory.

DTIC Science & Technology

1984-02-01

influence function , history value problems, classical solutions, global existence, decay. Work Unit Number 1 - Applied Analysis Sponsored by the United...introduce an " influence function " h, intended to JIN. characterize the rate at which memory fades, and construct an LP-type space of admissible...histories using the influence function as a weight. Here we use the term influence function to mean a positive, nonincreasing, real-valued function h e L (0

Global solutions to the equation of thermoelasticity with fading memory

NASA Astrophysics Data System (ADS)

Okada, Mari; Kawashima, Shuichi

2017-07-01

We consider the initial-history value problem for the one-dimensional equation of thermoelasticity with fading memory. It is proved that if the data are smooth and small, then a unique smooth solution exists globally in time and converges to the constant equilibrium state as time goes to infinity. Our proof is based on a technical energy method which makes use of the strict convexity of the entropy function and the properties of strongly positive definite kernels.

Impaired emotional autobiographical memory associated with right amygdalar-hippocampal atrophy in Alzheimer's disease patients.

PubMed

Philippi, Nathalie; Botzung, Anne; Noblet, Vincent; Rousseau, François; Després, Olivier; Cretin, Benjamin; Kremer, Stéphane; Blanc, Frédéric; Manning, Liliann

2015-01-01

We studied the influence of emotions on autobiographical memory (AbM) in patients with Alzheimer's disease (AD), characteristically triggering atrophy in the hippocampus and the amygdala, two crucial structures sustaining memory and emotional processing. Our first aim was to analyze the influence of emotion on AbM in AD patients, on both the proportion and the specificity of emotional memories. Additionally, we sought to determine the relationship of emotional AbM to amygdalar-hippocampal volumes. Eighteen prodromal to mild AD patients and 18 age-matched healthy controls were included. We obtained 30 autobiographical memories per participant using the modified Crovitz test (MCT). Analyses were performed on global scores, rates and specificity scores of the emotional vs. neutral categories of memories. Amygdalar-hippocampal volumes were extracted from 3D T1-weighted MRI scans and tested for correlations with behavioral data. Overall, AD patients displayed a deficit in emotional AbMs as they elicited less emotional memories than the controls, however, the specificity of those memories was preserved. The deficit likely implied retrieval or storage as it was extended in time and without reminiscence bump effect. Global scores and rates of emotional memories, but not the specificity scores, were correlated to right amygdalar and hippocampal volumes, indicating that atrophy in these structures has a central role in the deficit observed. Conversely, emotional memories were more specific than neutral memories in both groups, reflecting an enhancement effect of emotion that could be supported by other brain regions that are spared during the early stages of the disease.

Shared reality in interpersonal relationships.

PubMed

Andersen, Susan M; Przybylinski, Elizabeth

2017-11-24

Close relationships afford us opportunities to create and maintain meaning systems as shared perceptions of ourselves and the world. Establishing a sense of mutual understanding allows for creating and maintaining lasting social bonds, and as such, is important in human relations. In a related vein, it has long been known that knowledge of significant others in one's life is stored in memory and evoked with new persons-in the social-cognitive process of 'transference'-imbuing new encounters with significance and leading to predictable cognitive, evaluative, motivational, and behavioral consequences, as well as shifts in the self and self-regulation, depending on the particular significant other evoked. In these pages, we briefly review the literature on meaning as interpersonally defined and then selectively review research on transference in interpersonal perception. Based on this, we then highlight a recent series of studies focused on shared meaning systems in transference. The highlighted studies show that values and beliefs that develop in close relationships (as shared reality) are linked in memory to significant-other knowledge, and thus, are indirectly activated (made accessible) when cues in a new person implicitly activate that significant-other knowledge (in transference), with these shared beliefs then actively pursued with the new person and even protected against threat. This also confers a sense of mutual understanding, and all told, serves both relational and epistemic functions. In concluding, we consider as well the relevance of co-construction of shared reality n such processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Early differential sensitivity of evoked-potentials to local and global shape during the perception of three-dimensional objects.

PubMed

Leek, E Charles; Roberts, Mark; Oliver, Zoe J; Cristino, Filipe; Pegna, Alan J

2016-08-01

Here we investigated the time course underlying differential processing of local and global shape information during the perception of complex three-dimensional (3D) objects. Observers made shape matching judgments about pairs of sequentially presented multi-part novel objects. Event-related potentials (ERPs) were used to measure perceptual sensitivity to 3D shape differences in terms of local part structure and global shape configuration - based on predictions derived from hierarchical structural description models of object recognition. There were three types of different object trials in which stimulus pairs (1) shared local parts but differed in global shape configuration; (2) contained different local parts but shared global configuration or (3) shared neither local parts nor global configuration. Analyses of the ERP data showed differential amplitude modulation as a function of shape similarity as early as the N1 component between 146-215ms post-stimulus onset. These negative amplitude deflections were more similar between objects sharing global shape configuration than local part structure. Differentiation among all stimulus types was reflected in N2 amplitude modulations between 276-330ms. sLORETA inverse solutions showed stronger involvement of left occipitotemporal areas during the N1 for object discrimination weighted towards local part structure. The results suggest that the perception of 3D object shape involves parallel processing of information at local and global scales. This processing is characterised by relatively slow derivation of 'fine-grained' local shape structure, and fast derivation of 'coarse-grained' global shape configuration. We propose that the rapid early derivation of global shape attributes underlies the observed patterns of N1 amplitude modulations. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Memory bias for negative emotional words in recognition memory is driven by effects of category membership

PubMed Central

White, Corey N.; Kapucu, Aycan; Bruno, Davide; Rotello, Caren M.; Ratcliff, Roger

2014-01-01

Recognition memory studies often find that emotional items are more likely than neutral items to be labeled as studied. Previous work suggests this bias is driven by increased memory strength/familiarity for emotional items. We explored strength and bias interpretations of this effect with the conjecture that emotional stimuli might seem more familiar because they share features with studied items from the same category. Categorical effects were manipulated in a recognition task by presenting lists with a small, medium, or large proportion of emotional words. The liberal memory bias for emotional words was only observed when a medium or large proportion of categorized words were presented in the lists. Similar, though weaker, effects were observed with categorized words that were not emotional (animal names). These results suggest that liberal memory bias for emotional items may be largely driven by effects of category membership. PMID:24303902

Memory: Enduring Traces of Perceptual and Reflective Attention

PubMed Central

Chun, Marvin M.; Johnson, Marcia K.

2011-01-01

Attention and memory are typically studied as separate topics, but they are highly intertwined. Here we discuss the relation between memory and two fundamental types of attention: perceptual and reflective. Memory is the persisting consequence of cognitive activities initiated by and/or focused on external information from the environment (perceptual attention) and initiated by and/or focused on internal mental representations (reflective attention). We consider three key questions for advancing a cognitive neuroscience of attention and memory: To what extent do perception and reflection share representational areas? To what extent are the control processes that select, maintain, and manipulate perceptual and reflective information subserved by common areas and networks? During perception and reflection, to what extent are common areas responsible for binding features together to create complex, episodic memories and for reviving them later? Considering similarities and differences in perceptual and reflective attention helps integrate a broad range of findings and raises important unresolved issues. PMID:22099456

Memory bias for negative emotional words in recognition memory is driven by effects of category membership.

PubMed

White, Corey N; Kapucu, Aycan; Bruno, Davide; Rotello, Caren M; Ratcliff, Roger

2014-01-01

Recognition memory studies often find that emotional items are more likely than neutral items to be labelled as studied. Previous work suggests this bias is driven by increased memory strength/familiarity for emotional items. We explored strength and bias interpretations of this effect with the conjecture that emotional stimuli might seem more familiar because they share features with studied items from the same category. Categorical effects were manipulated in a recognition task by presenting lists with a small, medium or large proportion of emotional words. The liberal memory bias for emotional words was only observed when a medium or large proportion of categorised words were presented in the lists. Similar, though weaker, effects were observed with categorised words that were not emotional (animal names). These results suggest that liberal memory bias for emotional items may be largely driven by effects of category membership.

Working Memory and Parent-Rated Components of Attention in Middle Childhood: A Behavioral Genetic Study

PubMed Central

Deater-Deckard, Kirby; Cutting, Laurie; Thompson, Lee A.; Petrill, Stephen A.

2012-01-01

The purpose of the current study was to investigate potential genetic and environmental correlations between working memory and three behavioral aspects of the attention network (i.e., executive, alerting, and orienting) using a twin design. Data were from 90 monozygotic (39% male) and 112 same-sex dizygotic (41% male) twins. Individual differences in working memory performance (digit span) and parent-rated measures of executive, alerting, and orienting attention included modest to moderate genetic variance, modest shared environmental variance, and modest to moderate nonshared environmental variance. As hypothesized, working memory performance was correlated with executive and alerting attention, but not orienting attention. The correlation between working memory, executive attention, and alerting attention was completely accounted for by overlapping genetic covariance, suggesting a common genetic mechanism or mechanisms underlying the links between working memory and certain parent-rated indicators of attentive behavior. PMID:21948215

Developmental reversals in false memory: Effects of emotional valence and arousal.

PubMed

Brainerd, C J; Holliday, R E; Reyna, V F; Yang, Y; Toglia, M P

2010-10-01

Do the emotional valence and arousal of events distort children's memories? Do valence and arousal modulate counterintuitive age increases in false memory? We investigated those questions in children, adolescents, and adults using the Cornell/Cortland Emotion Lists, a word list pool that induces false memories and in which valence and arousal can be manipulated factorially. False memories increased with age for unpresented semantic associates of word lists, and net accuracy (the ratio of true memory to total memory) decreased with age. These surprising developmental trends were more pronounced for negatively valenced materials than for positively valenced materials, they were more pronounced for high-arousal materials than for low-arousal materials, and developmental increases in the effects of arousal were small in comparison with developmental increases in the effects of valence. These findings have ramifications for legal applications of false memory research; materials that share the emotional hallmark of crimes (events that are negatively valenced and arousing) produced the largest age increases in false memory and the largest age declines in net accuracy. Copyright 2010 Elsevier Inc. All rights reserved.

Spatial working memory interferes with explicit, but not probabilistic cuing of spatial attention.

PubMed

Won, Bo-Yeong; Jiang, Yuhong V

2015-05-01

Recent empirical and theoretical work has depicted a close relationship between visual attention and visual working memory. For example, rehearsal in spatial working memory depends on spatial attention, whereas adding a secondary spatial working memory task impairs attentional deployment in visual search. These findings have led to the proposal that working memory is attention directed toward internal representations. Here, we show that the close relationship between these 2 constructs is limited to some but not all forms of spatial attention. In 5 experiments, participants held color arrays, dot locations, or a sequence of dots in working memory. During the memory retention interval, they performed a T-among-L visual search task. Crucially, the probable target location was cued either implicitly through location probability learning or explicitly with a central arrow or verbal instruction. Our results showed that whereas imposing a visual working memory load diminished the effectiveness of explicit cuing, it did not interfere with probability cuing. We conclude that spatial working memory shares similar mechanisms with explicit, goal-driven attention but is dissociated from implicitly learned attention. (c) 2015 APA, all rights reserved).

Spatial working memory interferes with explicit, but not probabilistic cuing of spatial attention

PubMed Central

Won, Bo-Yeong; Jiang, Yuhong V.

2014-01-01

Recent empirical and theoretical work has depicted a close relationship between visual attention and visual working memory. For example, rehearsal in spatial working memory depends on spatial attention, whereas adding a secondary spatial working memory task impairs attentional deployment in visual search. These findings have led to the proposal that working memory is attention directed toward internal representations. Here we show that the close relationship between these two constructs is limited to some but not all forms of spatial attention. In five experiments, participants held color arrays, dot locations, or a sequence of dots in working memory. During the memory retention interval they performed a T-among-L visual search task. Crucially, the probable target location was cued either implicitly through location probability learning, or explicitly with a central arrow or verbal instruction. Our results showed that whereas imposing a visual working memory load diminished the effectiveness of explicit cuing, it did not interfere with probability cuing. We conclude that spatial working memory shares similar mechanisms with explicit, goal-driven attention but is dissociated from implicitly learned attention. PMID:25401460

Studies on B-cell memory. III. T-dependent aspect of B memory generation in mice immunized with T-independent type-2(TI-2) antigen.

PubMed

Hosokawa, T; Tanaka, Y; Aoike, A; Kawai, K; Muramatsu, S

1984-09-01

The time course of B-cell memory development to a dinitrophenyl (DNP) T-independent type-2 (TI-2) antigen was investigated by adoptive cell transfer. Strong IgM and IgG memory developed in BALB/c mice after immunization with DNP-dextran, to be recalled by challenge with either T-dependent (TD) antigen or TI-2 antigen. However, only weak IgM memory and very feeble IgG memory were detected in athymic nude mice receiving the same immunization as euthymic mice. Once memory was established under probable T cell influence, its recall by TI-2 antigen challenge seemed independent of T cell help and did not require sharing of carriers between priming and challenge antigens. The following may be concluded. (i) Long-term IgM and IgG memory is induced by TI-2 antigen priming in the presence of functional T cells. (ii) The class switch from IgM to IgG in the memory B cell pool is driven effectively by TI-2 antigen and is probably T cell-dependent.

Angular default mode network connectivity across working memory load.

PubMed

Vatansever, D; Manktelow, A E; Sahakian, B J; Menon, D K; Stamatakis, E A

2017-01-01

Initially identified during no-task, baseline conditions, it has now been suggested that the default mode network (DMN) engages during a variety of working memory paradigms through its flexible interactions with other large-scale brain networks. Nevertheless, its contribution to whole-brain connectivity dynamics across increasing working memory load has not been explicitly assessed. The aim of our study was to determine which DMN hubs relate to working memory task performance during an fMRI-based n-back paradigm with parametric increases in difficulty. Using a voxel-wise metric, termed the intrinsic connectivity contrast (ICC), we found that the bilateral angular gyri (core DMN hubs) displayed the greatest change in global connectivity across three levels of n-back task load. Subsequent seed-based functional connectivity analysis revealed that the angular DMN regions robustly interact with other large-scale brain networks, suggesting a potential involvement in the global integration of information. Further support for this hypothesis comes from the significant correlations we found between angular gyri connectivity and reaction times to correct responses. The implication from our study is that the DMN is actively involved during the n-back task and thus plays an important role related to working memory, with its core angular regions contributing to the changes in global brain connectivity in response to increasing environmental demands. Hum Brain Mapp 38:41-52, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Visual working memory for global, object, and part-based information.

PubMed

Patterson, Michael D; Bly, Benjamin Martin; Porcelli, Anthony J; Rypma, Bart

2007-06-01

We investigated visual working memory for novel objects and parts of novel objects. After a delay period, participants showed strikingly more accurate performance recognizing a single whole object than the parts of that object. This bias to remember whole objects, rather than parts, persisted even when the division between parts was clearly defined and the parts were disconnected from each other so that, in order to remember the single whole object, the participants needed to mentally combine the parts. In addition, the bias was confirmed when the parts were divided by color. These experiments indicated that holistic perceptual-grouping biases are automatically used to organize storage in visual working memory. In addition, our results suggested that the bias was impervious to top-down consciously directed control, because when task demands were manipulated through instruction and catch trials, the participants still recognized whole objects more quickly and more accurately than their parts. This bias persisted even when the whole objects were novel and the parts were familiar. We propose that visual working memory representations depend primarily on the global configural properties of whole objects, rather than part-based representations, even when the parts themselves can be clearly perceived as individual objects. This global configural bias beneficially reduces memory load on a capacity-limited system operating in a complex visual environment, because fewer distinct items must be remembered.

Computational performance of a smoothed particle hydrodynamics simulation for shared-memory parallel computing

NASA Astrophysics Data System (ADS)

Nishiura, Daisuke; Furuichi, Mikito; Sakaguchi, Hide

2015-09-01

The computational performance of a smoothed particle hydrodynamics (SPH) simulation is investigated for three types of current shared-memory parallel computer devices: many integrated core (MIC) processors, graphics processing units (GPUs), and multi-core CPUs. We are especially interested in efficient shared-memory allocation methods for each chipset, because the efficient data access patterns differ between compute unified device architecture (CUDA) programming for GPUs and OpenMP programming for MIC processors and multi-core CPUs. We first introduce several parallel implementation techniques for the SPH code, and then examine these on our target computer architectures to determine the most effective algorithms for each processor unit. In addition, we evaluate the effective computing performance and power efficiency of the SPH simulation on each architecture, as these are critical metrics for overall performance in a multi-device environment. In our benchmark test, the GPU is found to produce the best arithmetic performance as a standalone device unit, and gives the most efficient power consumption. The multi-core CPU obtains the most effective computing performance. The computational speed of the MIC processor on Xeon Phi approached that of two Xeon CPUs. This indicates that using MICs is an attractive choice for existing SPH codes on multi-core CPUs parallelized by OpenMP, as it gains computational acceleration without the need for significant changes to the source code.

Real-time implementations of image segmentation algorithms on shared memory multicore architecture: a survey (Conference Presentation)

NASA Astrophysics Data System (ADS)

Akil, Mohamed

2017-05-01

The real-time processing is getting more and more important in many image processing applications. Image segmentation is one of the most fundamental tasks image analysis. As a consequence, many different approaches for image segmentation have been proposed. The watershed transform is a well-known image segmentation tool. The watershed transform is a very data intensive task. To achieve acceleration and obtain real-time processing of watershed algorithms, parallel architectures and programming models for multicore computing have been developed. This paper focuses on the survey of the approaches for parallel implementation of sequential watershed algorithms on multicore general purpose CPUs: homogeneous multicore processor with shared memory. To achieve an efficient parallel implementation, it's necessary to explore different strategies (parallelization/distribution/distributed scheduling) combined with different acceleration and optimization techniques to enhance parallelism. In this paper, we give a comparison of various parallelization of sequential watershed algorithms on shared memory multicore architecture. We analyze the performance measurements of each parallel implementation and the impact of the different sources of overhead on the performance of the parallel implementations. In this comparison study, we also discuss the advantages and disadvantages of the parallel programming models. Thus, we compare the OpenMP (an application programming interface for multi-Processing) with Ptheads (POSIX Threads) to illustrate the impact of each parallel programming model on the performance of the parallel implementations.

Architectures for reasoning in parallel

NASA Technical Reports Server (NTRS)

Hall, Lawrence O.

1989-01-01

The research conducted has dealt with rule-based expert systems. The algorithms that may lead to effective parallelization of them were investigated. Both the forward and backward chained control paradigms were investigated in the course of this work. The best computer architecture for the developed and investigated algorithms has been researched. Two experimental vehicles were developed to facilitate this research. They are Backpac, a parallel backward chained rule-based reasoning system and Datapac, a parallel forward chained rule-based reasoning system. Both systems have been written in Multilisp, a version of Lisp which contains the parallel construct, future. Applying the future function to a function causes the function to become a task parallel to the spawning task. Additionally, Backpac and Datapac have been run on several disparate parallel processors. The machines are an Encore Multimax with 10 processors, the Concert Multiprocessor with 64 processors, and a 32 processor BBN GP1000. Both the Concert and the GP1000 are switch-based machines. The Multimax has all its processors hung off a common bus. All are shared memory machines, but have different schemes for sharing the memory and different locales for the shared memory. The main results of the investigations come from experiments on the 10 processor Encore and the Concert with partitions of 32 or less processors. Additionally, experiments have been run with a stripped down version of EMYCIN.

Global similarity predicts dissociation of classification and recognition: evidence questioning the implicit-explicit learning distinction in amnesia.

PubMed

Jamieson, Randall K; Holmes, Signy; Mewhort, D J K

2010-11-01

Dissociation of classification and recognition in amnesia is widely taken to imply 2 functional systems: an implicit procedural-learning system that is spared in amnesia and an explicit episodic-learning system that is compromised. We argue that both tasks reflect the global similarity of probes to memory. In classification, subjects sort unstudied grammatical exemplars from lures, whereas in recognition, they sort studied grammatical exemplars from lures. Hence, global similarity is necessarily greater in recognition than in classification. Moreover, a grammatical exemplar's similarity to studied exemplars is a nonlinear function of the integrity of the data in memory. Assuming that data integrity is better for control subjects than for subjects with amnesia, the nonlinear relation combined with the advantage for recognition over classification predicts the dissociation of recognition and classification. To illustrate the dissociation of recognition and classification in healthy undergraduates, we manipulated study time to vary the integrity of the data in memory and brought the dissociation under experimental control. We argue that the dissociation reflects a general cost in memory rather than a selective impairment of separate procedural and episodic systems. (c) 2010 APA, all rights reserved

Similar verbal memory impairments in schizophrenia and healthy aging. Implications for understanding of neural mechanisms.

PubMed

Silver, Henry; Bilker, Warren B

2015-03-30

Memory is impaired in schizophrenia patients but it is not clear whether this is specific to the illness and whether different types of memory (verbal and nonverbal) or memories in different cognitive domains (executive, object recognition) are similarly affected. To study relationships between memory impairments and schizophrenia we compared memory functions in 77 schizophrenia patients, 58 elderly healthy individuals and 41 young healthy individuals. Tests included verbal associative and logical memory and memory in executive and object recognition domains. We compared relationships of memory functions to each other and to other cognitive functions including psychomotor speed and verbal and spatial working memory. Compared to the young healthy group, schizophrenia patients and elderly healthy individuals showed similar severe impairment in logical memory and in the ability to learn new associations (NAL), and similar but less severe impairment in spatial working memory and executive and object memory. Verbal working memory was significantly more impaired in schizophrenia patients than in the healthy elderly. Verbal episodic memory impairment in schizophrenia may share common mechanisms with similar impairment in healthy aging. Impairment in verbal working memory in contrast may reflect mechanisms specific to schizophrenia. Study of verbal explicit memory impairment tapped by the NAL index may advance understanding of abnormal hippocampus dependent mechanisms common to schizophrenia and aging. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Making the case that episodic recollection is attributable to operations occurring at retrieval rather than to content stored in a dedicated subsystem of long-term memory.

PubMed

Klein, Stanley B

2013-01-01

Episodic memory often is conceptualized as a uniquely human system of long-term memory that makes available knowledge accompanied by the temporal and spatial context in which that knowledge was acquired. Retrieval from episodic memory entails a form of first-person subjectivity called autonoetic consciousness that provides a sense that a recollection was something that took place in the experiencer's personal past. In this paper I expand on this definition of episodic memory. Specifically, I suggest that (1) the core features assumed unique to episodic memory are shared by semantic memory, (2) episodic memory cannot be fully understood unless one appreciates that episodic recollection requires the coordinated function of a number of distinct, yet interacting, "enabling" systems. Although these systems-ownership, self, subjective temporality, and agency-are not traditionally viewed as memorial in nature, each is necessary for episodic recollection and jointly they may be sufficient, and (3) the type of subjective awareness provided by episodic recollection (autonoetic) is relational rather than intrinsic-i.e., it can be lost in certain patient populations, thus rendering episodic memory content indistinguishable from the content of semantic long-term memory.

Multi-layered epigenetic mechanisms contribute to transcriptional memory in T lymphocytes.

PubMed

Dunn, Jennifer; McCuaig, Robert; Tu, Wen Juan; Hardy, Kristine; Rao, Sudha

2015-05-06

Immunological memory is the ability of the immune system to respond more rapidly and effectively to previously encountered pathogens, a key feature of adaptive immunity. The capacity of memory T cells to "remember" previous cellular responses to specific antigens ultimately resides in their unique patterns of gene expression. Following re-exposure to an antigen, previously activated genes are transcribed more rapidly and robustly in memory T cells compared to their naïve counterparts. The ability for cells to remember past transcriptional responses is termed "adaptive transcriptional memory". Recent global epigenome studies suggest that epigenetic mechanisms are central to establishing and maintaining transcriptional memory, with elegant studies in model organisms providing tantalizing insights into the epigenetic programs that contribute to adaptive immunity. These epigenetic mechanisms are diverse, and include not only classical acetylation and methylation events, but also exciting and less well-known mechanisms involving histone structure, upstream signalling pathways, and nuclear localisation of genomic regions. Current global health challenges in areas such as tuberculosis and influenza demand not only more effective and safer vaccines, but also vaccines for a wider range of health priorities, including HIV, cancer, and emerging pathogens such as Ebola. Understanding the multi-layered epigenetic mechanisms that underpin the rapid recall responses of memory T cells following reactivation is a critical component of this development pathway.

Self-awareness of memory function in Parkinson's disease in relation to mood and symptom severity.

PubMed

Sitek, Emilia J; Sołtan, Witold; Wieczorek, Dariusz; Robowski, Piotr; Sławek, Jarosław

2011-03-01

In clinical practice, discrepancies are observed between self and proxy reports of various aspects of Parkinson's disease (PD). This study aimed at assessing self-awareness of memory function in PD both by comparing patients' and caregivers' questionnaire ratings of the patients' memory and by correlating subjective ratings with verbal learning results. Forty-five patient-proxy pairs participated in the study. Self-Rating Scale of Memory Functions was used as a questionnaire subjective measure. Auditory Verbal Learning Test (AVLT) was applied to assess verbal memory, Stroop test to assess cognitive control and Mini-Mental State Examination (MMSE) for global cognitive assessment. Patient self-reports did not diverge appreciably from proxy reports when global scores were considered, but patient-proxy consistency was low for individual items with the exception of those referring to verbal recall. Both patient and proxy ratings were moderately correlated with the objective measures. Patient-proxy discrepancies were associated with lower verbal learning, poor cognitive control and more severe PD symptomatology. Moreover, depression was associated with patients' overestimation of symptoms. Self-awareness of memory function is relatively well preserved in PD, but is negatively affected by depressive symptoms. Patient-proxy discrepancies increase also with disease severity, degree of memory problems and cognitive control deficits. Caregivers seem to be unaware of the specificity of memory problems in PD and report only some of them, mainly those related to verbal recall.

A biometric latent curve analysis of memory decline in older men of the NAS-NRC twin registry.

PubMed

McArdle, John J; Plassman, Brenda L

2009-09-01

Previous research has shown cognitive abilities to have different biometric patterns of age-changes. We examined the variation in episodic memory (word recall task) for over 6,000 twin pairs who were initially aged 59-75, and were subsequently re-assessed up to three more times over 12 years. In cross-sectional analyses, variation in the number of words recalled independent of age was explained largely by non-shared influences (65-72%), with clear additive genetic influences (12-32%), and marginal shared family influences (1-18%). The longitudinal phenotypic analysis of the word recall task showed systematic linear declines over age, but several nonlinear models with more dramatic changes at later ages, improved the overall fit. A two-part spline model for the longitudinal twin data with an optimal turning point at age 74 led to: (a) a separation of non-shared environmental influences and transient measurement error (~50%); (b) strong additive genetic components of this latent curve (~44% at age 60) with increases (over 50%) up to age 74, but with no additional genetic variation after age 74; (c) the smaller influences of shared family environment (~15% at age 74) were constant over all ages; (d) non-shared effects play an important role over most of the life-span but diminish after age 74.

The analogy between dreams and the ancient art of memory is tempting but superficial.

PubMed

Axmacher, Nikolai; Fell, Juergen

2013-12-01

Although the analogy between dreams and ancient mnemotechniques is tempting because they share several phenomenological characteristics, this analogy is superficial at a closer look. Unlike mneomotechnically encoded material, rapid eye movement (REM) dreams are inherently difficult to remember, do not usually allow conscious subsequent retrieval of all interconnected elements, and have been found to support subsequent episodic memory in only rare cases.

Parallel Programming Paradigms

DTIC Science & Technology

1987-07-01

Unclassified IS.. DECLASSIFICATIONIOOWNGRADIN G 16. DISTRIBUTION STATEMENT (of this Report) Distribution of this report is unlimited. 17...8416878 and by the Office of Naval Research Contracts No. N00014-86-K-0264 and No. N00014-85- K-0328. 8 ?~~ O . G 1 49 II Parallel Programming Paradigms...processors -. "to fetch from the same memory cell (list head) and thus seems to favor a shared memory - g implementation [37). In this dissertation, we

Time perspective and positivity effects in Alzheimer's disease.

PubMed

Bohn, Linzy; Kwong See, Sheree T; Fung, Helene H

2016-09-01

This study tested whether time perspective, a central tenant of socioemotional selectivity theory (Carstensen, 2006), moderates positivity effects in emotional memory. To provide measures of time perspective, young (YA; M = 22.48 years), young-old (YO; M = 67.56 years), old-old adults (OO; M = 80.24 years), and participants with moderate severity Alzheimer's disease (PAD; M = 84.28 years) completed a line task and reported subjective age. As expected, YA, YO, and OO reported successively more constrained future time perspectives. PAD showed distortion in time perspective, envisioning a future comparable with the YO, although closer matched in chronological age to OO adults. To evince positivity effects, participants were oriented to pairs of emotional images and were then tested for memory (recall and recognition) of the images. Recall and recognition memory for the images indicated an age-related advantage for positive over negative material (positivity effects). Time perspective, however, did not moderate these age effects. In memory performance, PAD were more comparable with OO adults with whom they shared a similar chronological age, rather than YO adults, who had a corresponding time perspective. These results suggest that age correlates that are shared by PAD and OO, such as reduced processing resources, rather than time perspective, may drive the age associated positivity effects. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Global robust stability of bidirectional associative memory neural networks with multiple time delays.

PubMed

Senan, Sibel; Arik, Sabri

2007-10-01

This correspondence presents a sufficient condition for the existence, uniqueness, and global robust asymptotic stability of the equilibrium point for bidirectional associative memory neural networks with discrete time delays. The results impose constraint conditions on the network parameters of the neural system independently of the delay parameter, and they are applicable to all bounded continuous nonmonotonic neuron activation functions. Some numerical examples are given to compare our results with the previous robust stability results derived in the literature.

Periodic bidirectional associative memory neural networks with distributed delays

NASA Astrophysics Data System (ADS)

Chen, Anping; Huang, Lihong; Liu, Zhigang; Cao, Jinde

2006-05-01

Some sufficient conditions are obtained for the existence and global exponential stability of a periodic solution to the general bidirectional associative memory (BAM) neural networks with distributed delays by using the continuation theorem of Mawhin's coincidence degree theory and the Lyapunov functional method and the Young's inequality technique. These results are helpful for designing a globally exponentially stable and periodic oscillatory BAM neural network, and the conditions can be easily verified and be applied in practice. An example is also given to illustrate our results.

Cerebral Glucose Metabolism is Associated with Verbal but not Visual Memory Performance in Community-Dwelling Older Adults.

PubMed

Gardener, Samantha L; Sohrabi, Hamid R; Shen, Kai-Kai; Rainey-Smith, Stephanie R; Weinborn, Michael; Bates, Kristyn A; Shah, Tejal; Foster, Jonathan K; Lenzo, Nat; Salvado, Olivier; Laske, Christoph; Laws, Simon M; Taddei, Kevin; Verdile, Giuseppe; Martins, Ralph N

2016-03-31

Increasing evidence suggests that Alzheimer's disease (AD) sufferers show region-specific reductions in cerebral glucose metabolism, as measured by [18F]-fluoro-2-deoxyglucose positron emission tomography (18F-FDG PET). We investigated preclinical disease stage by cross-sectionally examining the association between global cognition, verbal and visual memory, and 18F-FDG PET standardized uptake value ratio (SUVR) in 43 healthy control individuals, subsequently focusing on differences between subjective memory complainers and non-memory complainers. The 18F-FDG PET regions of interest investigated include the hippocampus, amygdala, posterior cingulate, superior parietal, entorhinal cortices, frontal cortex, temporal cortex, and inferior parietal region. In the cohort as a whole, verbal logical memory immediate recall was positively associated with 18F-FDG PET SUVR in both the left hippocampus and right amygdala. There were no associations observed between global cognition, delayed recall in logical memory, or visual reproduction and 18F-FDG PET SUVR. Following stratification of the cohort into subjective memory complainers and non-complainers, verbal logical memory immediate recall was positively associated with 18F-FDG PET SUVR in the right amygdala in those with subjective memory complaints. There were no significant associations observed in non-memory complainers between 18F-FDG PET SUVR in regions of interest and cognitive performance. We observed subjective memory complaint-specific associations between 18F-FDG PET SUVR and immediate verbal memory performance in our cohort, however found no associations between delayed recall of verbal memory performance or visual memory performance. It is here argued that the neural mechanisms underlying verbal and visual memory performance may in fact differ in their pathways, and the characteristic reduction of 18F-FDG PET SUVR observed in this and previous studies likely reflects the pathophysiological changes in specific brain regions that occur in preclinical AD.

5-HT2a receptor in mPFC influences context-guided reconsolidation of object memory in perirhinal cortex.

PubMed

Morici, Juan Facundo; Miranda, Magdalena; Gallo, Francisco Tomás; Zanoni, Belén; Bekinschtein, Pedro; Weisstaub, Noelia V

2018-05-02

Context-dependent memories may guide adaptive behavior relaying in previous experience while updating stored information through reconsolidation. Retrieval can be triggered by partial and shared cues. When the cue is presented, the most relevant memory should be updated. In a contextual version of the object recognition task, we examined the effect of medial PFC (mPFC) serotonin 2a receptor (5-HT2aR) blockade during retrieval in reconsolidation of competing objects memories. We found that mPFC 5-HT2aR controls retrieval and reconsolidation of object memories in the perirhinal cortex (PRH), but not in the dorsal hippocampus in rats. Also, reconsolidation of objects memories in PRH required a functional interaction between the ventral hippocampus and the mPFC. Our results indicate that in the presence of conflicting information at retrieval, mPFC 5-HT2aR may facilitate top-down context-guided control over PRH to control the behavioral response and object memory reconsolidation. © 2018, Morici et al.

5-HT2a receptor in mPFC influences context-guided reconsolidation of object memory in perirhinal cortex

PubMed Central

Morici, Juan Facundo; Miranda, Magdalena; Gallo, Francisco Tomás; Zanoni, Belén; Bekinschtein, Pedro

2018-01-01

Context-dependent memories may guide adaptive behavior relaying in previous experience while updating stored information through reconsolidation. Retrieval can be triggered by partial and shared cues. When the cue is presented, the most relevant memory should be updated. In a contextual version of the object recognition task, we examined the effect of medial PFC (mPFC) serotonin 2a receptor (5-HT2aR) blockade during retrieval in reconsolidation of competing objects memories. We found that mPFC 5-HT2aR controls retrieval and reconsolidation of object memories in the perirhinal cortex (PRH), but not in the dorsal hippocampus in rats. Also, reconsolidation of objects memories in PRH required a functional interaction between the ventral hippocampus and the mPFC. Our results indicate that in the presence of conflicting information at retrieval, mPFC 5-HT2aR may facilitate top-down context-guided control over PRH to control the behavioral response and object memory reconsolidation. PMID:29717980

Applications considerations in the system design of highly concurrent multiprocessors

NASA Technical Reports Server (NTRS)

Lundstrom, Stephen F.

1987-01-01

A flow model processor approach to parallel processing is described, using very-high-performance individual processors, high-speed circuit switched interconnection networks, and a high-speed synchronization capability to minimize the effect of the inherently serial portions of applications on performance. Design studies related to the determination of the number of processors, the memory organization, and the structure of the networks used to interconnect the processor and memory resources are discussed. Simulations indicate that applications centered on the large shared data memory should be able to sustain over 500 million floating point operations per second.

Neural Differentiation of Incorrectly Predicted Memories.

PubMed

Kim, Ghootae; Norman, Kenneth A; Turk-Browne, Nicholas B

2017-02-22

When an item is predicted in a particular context but the prediction is violated, memory for that item is weakened (Kim et al., 2014). Here, we explore what happens when such previously mispredicted items are later reencountered. According to prior neural network simulations, this sequence of events-misprediction and subsequent restudy-should lead to differentiation of the item's neural representation from the previous context (on which the misprediction was based). Specifically, misprediction weakens connections in the representation to features shared with the previous context and restudy allows new features to be incorporated into the representation that are not shared with the previous context. This cycle of misprediction and restudy should have the net effect of moving the item's neural representation away from the neural representation of the previous context. We tested this hypothesis using human fMRI by tracking changes in item-specific BOLD activity patterns in the hippocampus, a key structure for representing memories and generating predictions. In left CA2/3/DG, we found greater neural differentiation for items that were repeatedly mispredicted and restudied compared with items from a control condition that was identical except without misprediction. We also measured prediction strength in a trial-by-trial fashion and found that greater misprediction for an item led to more differentiation, further supporting our hypothesis. Therefore, the consequences of prediction error go beyond memory weakening. If the mispredicted item is restudied, the brain adaptively differentiates its memory representation to improve the accuracy of subsequent predictions and to shield it from further weakening. SIGNIFICANCE STATEMENT Competition between overlapping memories leads to weakening of nontarget memories over time, making it easier to access target memories. However, a nontarget memory in one context might become a target memory in another context. How do such memories get restrengthened without increasing competition again? Computational models suggest that the brain handles this by reducing neural connections to the previous context and adding connections to new features that were not part of the previous context. The result is neural differentiation away from the previous context. Here, we provide support for this theory, using fMRI to track neural representations of individual memories in the hippocampus and how they change based on learning. Copyright © 2017 the authors 0270-6474/17/372022-10$15.00/0.

Ensuring correct rollback recovery in distributed shared memory systems

NASA Technical Reports Server (NTRS)

Janssens, Bob; Fuchs, W. Kent

1995-01-01

Distributed shared memory (DSM) implemented on a cluster of workstations is an increasingly attractive platform for executing parallel scientific applications. Checkpointing and rollback techniques can be used in such a system to allow the computation to progress in spite of the temporary failure of one or more processing nodes. This paper presents the design of an independent checkpointing method for DSM that takes advantage of DSM's specific properties to reduce error-free and rollback overhead. The scheme reduces the dependencies that need to be considered for correct rollback to those resulting from transfers of pages. Furthermore, in-transit messages can be recovered without the use of logging. We extend the scheme to a DSM implementation using lazy release consistency, where the frequency of dependencies is further reduced.

Merlin - Massively parallel heterogeneous computing

NASA Technical Reports Server (NTRS)

Wittie, Larry; Maples, Creve

1989-01-01

Hardware and software for Merlin, a new kind of massively parallel computing system, are described. Eight computers are linked as a 300-MIPS prototype to develop system software for a larger Merlin network with 16 to 64 nodes, totaling 600 to 3000 MIPS. These working prototypes help refine a mapped reflective memory technique that offers a new, very general way of linking many types of computer to form supercomputers. Processors share data selectively and rapidly on a word-by-word basis. Fast firmware virtual circuits are reconfigured to match topological needs of individual application programs. Merlin's low-latency memory-sharing interfaces solve many problems in the design of high-performance computing systems. The Merlin prototypes are intended to run parallel programs for scientific applications and to determine hardware and software needs for a future Teraflops Merlin network.

The Family in Us: Family History, Family Identity and Self-Reproductive Adaptive Behavior.

PubMed

Ferring, Dieter

2017-06-01

This contribution is an essay about the notion of family identity reflecting shared significant experiences within a family system originating a set of signs used in social communication within and between families. Significant experiences are considered as experiences of events that have an immediate impact on the adaptation of the family in a given socio-ecological and cultural context at a given historical time. It is assumed that family history is stored in a shared "family memory" holding both implicit and explicit knowledge and exerting an influence on the behavior of each family member. This is described as transgenerational family memory being constituted of a system of meaningful signs. The crucial dimension underlying the logic of this essay are the ideas of adaptation as well as self-reproduction of systems.

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 Parallel Saturation Algorithm on Shared Memory Architectures

NASA Technical Reports Server (NTRS)

Ezekiel, Jonathan; Siminiceanu

2007-01-01

Symbolic state-space generators are notoriously hard to parallelize. However, the Saturation algorithm implemented in the SMART verification tool differs from other sequential symbolic state-space generators in that it exploits the locality of ring events in asynchronous system models. This paper explores whether event locality can be utilized to efficiently parallelize Saturation on shared-memory architectures. Conceptually, we propose to parallelize the ring of events within a decision diagram node, which is technically realized via a thread pool. We discuss the challenges involved in our parallel design and conduct experimental studies on its prototypical implementation. On a dual-processor dual core PC, our studies show speed-ups for several example models, e.g., of up to 50% for a Kanban model, when compared to running our algorithm only on a single core.

Enhancing and Transforming Global Learning Communities with Augmented Reality

ERIC Educational Resources Information Center

Frydenberg, Mark; Andone, Diana

2018-01-01

Augmented and virtual reality applications bring new insights to real world objects and scenarios. This paper shares research results of the TalkTech project, an ongoing study investigating the impact of learning about new technologies as members of global communities. This study shares results of a collaborative learning project about augmented…

The temporal evolution of electromagnetic markers sensitive to the capacity limits of visual short-term memory.

PubMed

Mitchell, Daniel J; Cusack, Rhodri

2011-01-01

An electroencephalographic (EEG) marker of the limited contents of human visual short-term memory (VSTM) has previously been described. Termed contralateral delay activity, this consists of a sustained, posterior, negative potential that correlates with memory load and is greatest contralateral to the remembered hemifield. The current investigation replicates this finding and uses magnetoencephalography (MEG) to characterize its magnetic counterparts and their neural generators as they evolve throughout the memory delay. A parametric manipulation of memory load, within and beyond capacity limits, allows separation of signals that asymptote with behavioral VSTM performance from additional responses that contribute to a linear increase with set-size. Both EEG and MEG yielded bilateral signals that track the number of objects held in memory, and contralateral signals that are independent of memory load. In MEG, unlike EEG, the contralateral interaction between hemisphere and item load is much weaker, suggesting that bilateral and contralateral markers of memory load reflect distinct sources to which EEG and MEG are differentially sensitive. Nonetheless, source estimation allowed both the bilateral and the weaker contralateral capacity-limited responses to be localized, along with a load-independent contralateral signal. Sources of global and hemisphere-specific signals all localized to the posterior intraparietal sulcus during the early delay. However the bilateral load response peaked earlier and its generators shifted later in the delay. Therefore the hemifield-specific response may be more closely tied to memory maintenance while the global load response may be involved in initial processing of a limited number of attended objects, such as their individuation or consolidation into memory.

Resource-sharing between internal maintenance and external selection modulates attentional capture by working memory content.

PubMed

Kiyonaga, Anastasia; Egner, Tobias

2014-01-01

It is unclear why and under what circumstances working memory (WM) and attention interact. Here, we apply the logic of the time-based resource-sharing (TBRS) model of WM (e.g., Barrouillet et al., 2004) to explore the mixed findings of a separate, but related, literature that studies the guidance of visual attention by WM contents. Specifically, we hypothesize that the linkage between WM representations and visual attention is governed by a time-shared cognitive resource that alternately refreshes internal (WM) and selects external (visual attention) information. If this were the case, WM content should guide visual attention (involuntarily), but only when there is time for it to be refreshed in an internal focus of attention. To provide an initial test for this hypothesis, we examined whether the amount of unoccupied time during a WM delay could impact the magnitude of attentional capture by WM contents. Participants were presented with a series of visual search trials while they maintained a WM cue for a delayed-recognition test. WM cues could coincide with the search target, a distracter, or neither. We varied both the number of searches to be performed, and the amount of available time to perform them. Slowing of visual search by a WM matching distracter-and facilitation by a matching target-were curtailed when the delay was filled with fast-paced (refreshing-preventing) search trials, as was subsequent memory probe accuracy. WM content may, therefore, only capture visual attention when it can be refreshed, suggesting that internal (WM) and external attention demands reciprocally impact one another because they share a limited resource. The TBRS rationale can thus be applied in a novel context to explain why WM contents capture attention, and under what conditions that effect should be observed.

Resource-sharing between internal maintenance and external selection modulates attentional capture by working memory content

PubMed Central

Kiyonaga, Anastasia; Egner, Tobias

2014-01-01

It is unclear why and under what circumstances working memory (WM) and attention interact. Here, we apply the logic of the time-based resource-sharing (TBRS) model of WM (e.g., Barrouillet et al., 2004) to explore the mixed findings of a separate, but related, literature that studies the guidance of visual attention by WM contents. Specifically, we hypothesize that the linkage between WM representations and visual attention is governed by a time-shared cognitive resource that alternately refreshes internal (WM) and selects external (visual attention) information. If this were the case, WM content should guide visual attention (involuntarily), but only when there is time for it to be refreshed in an internal focus of attention. To provide an initial test for this hypothesis, we examined whether the amount of unoccupied time during a WM delay could impact the magnitude of attentional capture by WM contents. Participants were presented with a series of visual search trials while they maintained a WM cue for a delayed-recognition test. WM cues could coincide with the search target, a distracter, or neither. We varied both the number of searches to be performed, and the amount of available time to perform them. Slowing of visual search by a WM matching distracter—and facilitation by a matching target—were curtailed when the delay was filled with fast-paced (refreshing-preventing) search trials, as was subsequent memory probe accuracy. WM content may, therefore, only capture visual attention when it can be refreshed, suggesting that internal (WM) and external attention demands reciprocally impact one another because they share a limited resource. The TBRS rationale can thus be applied in a novel context to explain why WM contents capture attention, and under what conditions that effect should be observed. PMID:25221499

Robert Hooke's model of memory.

PubMed

Hintzman, Douglas L

2003-03-01

In 1682 the scientist and inventor Robert Hooke read a lecture to the Royal Society of London, in which he described a mechanistic model of human memory. Yet few psychologists today seem to have heard of Hooke's memory model. The lecture addressed questions of encoding, memory capacity, repetition, retrieval, and forgetting--some of these in a surprisingly modern way. Hooke's model shares several characteristics with the theory of Richard Semon, which came more than 200 years later, but it is more complete. Among the model's interesting properties are that (1) it allows for attention and other top-down influences on encoding; (2) it uses resonance to implement parallel, cue-dependent retrieval; (3) it explains memory for recency; (4) it offers a single-system account of repetition priming; and (5) the power law of forgetting can be derived from the model's assumptions in a straightforward way.

Constructing Memory, Imagination, and Empathy: A Cognitive Neuroscience Perspective

PubMed Central

Gaesser, Brendan

2012-01-01

Studies on memory, imagination, and empathy have largely progressed in isolation. Consequently, humans’ empathic tendencies to care about and help other people are considered independent of our ability to remember and imagine events. Despite this theoretical autonomy, work from across psychology, and neuroscience suggests that these cognitive abilities may be linked. In the present paper, I tentatively propose that humans’ ability to vividly imagine specific events (as supported by constructive memory) may facilitate prosocial intentions and behavior. Evidence of a relationship between memory, imagination, and empathy comes from research that shows imagination influences the perceived and actual likelihood an event occurs, improves intergroup relations, and shares a neural basis with memory and empathy. Although many questions remain, this paper outlines a new direction for research that investigates the role of imagination in promoting empathy and prosocial behavior. PMID:23440064

Cultural differences in rated typicality and perceived causes of memory changes in adulthood.

PubMed

Bottiroli, Sara; Cavallini, Elena; Fastame, Maria Chiara; Hertzog, Christopher

2013-01-01

This study examined cultural differences in stereotypes and attributions regarding aging and memory. Two subcultures belonging to the same country, Italy, were compared on general beliefs about memory. Sardinians live longer than other areas of Italy, which is a publically shared fact that informs stereotypes about that subculture. An innovative instrument evaluating simultaneously aging stereotypes and attributions about memory and memory change in adulthood was administered to 52 Sardinian participants and 52 Milanese individuals divided into three age groups: young (20-30), young-old (60-70), and old-old (71-85) adults. Both Milanese and Sardinians reported that memory decline across the life span is more typical than a pattern of stability or improvement. However, Sardinians viewed stability and improvement in memory as more typical than did the Milanese. Interestingly, cultural differences emerged in attributions about memory improvement. Although all Sardinian age groups rated nutrition and heredity as relevant causes in determining the memory decline, Sardinians' rated typicality of life-span memory improvement correlated strongly with causal attributions to a wide number of factors, including nutrition and heredity. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

The Role of Metarepresentation in the Production and Resolution of Referring Expressions.

PubMed

Horton, William S; Brennan, Susan E

2016-01-01

In this paper we consider the potential role of metarepresentation-the representation of another representation, or as commonly considered within cognitive science, the mental representation of another individual's knowledge and beliefs-in mediating definite reference and common ground in conversation. Using dialogues from a referential communication study in which speakers conversed in succession with two different addressees, we highlight ways in which interlocutors work together to successfully refer to objects, and achieve shared conceptualizations. We briefly review accounts of how such shared conceptualizations could be represented in memory, from simple associations between label and referent, to "triple co-presence" representations that track interlocutors in an episode of referring, to more elaborate metarepresentations that invoke theory of mind, mutual knowledge, or a model of a conversational partner. We consider how some forms of metarepresentation, once created and activated, could account for definite reference in conversation by appealing to ordinary processes in memory. We conclude that any representations that capture information about others' perspectives are likely to be relatively simple and subject to the same kinds of constraints on attention and memory that influence other kinds of cognitive representations.

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

Lyakh, Dmitry I.

An efficient parallel tensor transpose algorithm is suggested for shared-memory computing units, namely, multicore CPU, Intel Xeon Phi, and NVidia GPU. The algorithm operates on dense tensors (multidimensional arrays) and is based on the optimization of cache utilization on x86 CPU and the use of shared memory on NVidia GPU. From the applied side, the ultimate goal is to minimize the overhead encountered in the transformation of tensor contractions into matrix multiplications in computer implementations of advanced methods of quantum many-body theory (e.g., in electronic structure theory and nuclear physics). A particular accent is made on higher-dimensional tensors that typicallymore » appear in the so-called multireference correlated methods of electronic structure theory. Depending on tensor dimensionality, the presented optimized algorithms can achieve an order of magnitude speedup on x86 CPUs and 2-3 times speedup on NVidia Tesla K20X GPU with respect to the na ve scattering algorithm (no memory access optimization). Furthermore, the tensor transpose routines developed in this work have been incorporated into a general-purpose tensor algebra library (TAL-SH).« less